TY - CONF TI - Procedure for measuring and comparing fuel use and gaseous emissions for gas-direct injection versus port fuel injection vehicles AU - Singh, S. AU - Frey, H.C. C2 - 2017/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2017/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039147517&partnerID=MN8TOARS ER - TY - CONF TI - Procedure for evaluation of retrofitted scr-based emission control system for a passenger railroad locomotive AU - Rastogi, N. AU - Frey, H.C. C2 - 2017/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2017/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039160003&partnerID=MN8TOARS ER - TY - CONF TI - Identifying and transcending ideological barriers in the climate change public policy debate AU - Frey, H.C. C2 - 2017/// C3 - Air and Waste Management Association, A and WMA - Finding Common Ground on Climate Change Mitigation and Adaptation DA - 2017/// VL - 2017-October SP - 8-17 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85052332630&partnerID=MN8TOARS ER - TY - JOUR TI - High levels of endocrine pollutants in US streams during low flow due to insufficient wastewater dilution AU - Rice, Jacelyn AU - Westerhoff, Paul T2 - Nature Geoscience DA - 2017/// PY - 2017/// DO - 10.1038/NGEO2984 VL - 10 IS - 8 SP - 587-591 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85026671615&partnerID=MN8TOARS ER - TY - CONF TI - Mechanical Behavior of Sands Treated by Microbially Induced Calcite Precipitation at Low Confining Stress AU - Do, Jinung AU - Montoya, Brina M. AU - Gabr, M.A, T2 - 19th International Conference on Soil Mechanics and Geotechnical Engineering C2 - 2017/9// C3 - 19th International Conference on Soil Mechanics and Geotechnical Engineering CY - Seoul, South Korea DA - 2017/9// PY - 2017/9// ER - TY - CONF TI - Use of remote-sensing deformation monitoring for the assessment of levee section performance limit state AU - Bennett, V. AU - Nguyen, C. AU - Abdoun, T. AU - Helal, A. AU - Gabr, M. AU - Jones, C. AU - Bekaert, D. AU - Dudas, J. T2 - 19th International conference on soil mechanics and geotechnical engineering C2 - 2017/// C3 - Proceeding of the 19th International conference on soil mechanics and geotechnical engineering CY - Seoul, Korea DA - 2017/// PY - 2017/// ER - TY - CONF TI - Effect of Microbial Induced Calcite Precipitation on Compressibility and Hydraulic Conductivity of Coal Fly Ash AU - Safavizadeh, Shahin AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - Dam Safety 2017 C2 - 2017/// C3 - Dam Safety 2017 CY - San Antonio, Texas DA - 2017/// PY - 2017/// ER - TY - CONF TI - Effect of the Keying Angle on the Pullout Capacity of Suction Embedded Plate Anchor (SEPLA) in Clay AU - Ardebili, Zahra Aghazadeh AU - Gabr, M.A. AU - Rahman, M.S. T2 - ISOPE-I-17-089, The International Society of Offshore and Polar Engineers C2 - 2017/6// C3 - ISOPE-I-17-089, The International Society of Offshore and Polar Engineers CY - San Francisco, California DA - 2017/6// PY - 2017/6// ER - TY - CONF TI - Assessment of Subgrade Soils Stabilization Criteria AU - Mousavi, H. AU - Gabr, M.A. AU - Borden, R.H. T2 - International Conference on Highway Pavements & Airfield Technology C2 - 2017/// C3 - International Conference on Highway Pavements & Airfield Technology CY - Philadelphia, PA DA - 2017/// PY - 2017/8// ER - TY - CONF TI - Effect of Bio-Cementation on Performance of Coal Ash Ponds AU - Safavizadeh, S.S. AU - Montoya, B.M. AU - Gabr, M. T2 - Dam Safety 2017, Association of State Dam Safety Officials (ASDSO) C2 - 2017/// C3 - Proceedings from Dam Safety 2017, Association of State Dam Safety Officials (ASDSO) CY - San Antonio, Texas DA - 2017/// PY - 2017/// ER - TY - ER - TY - JOUR TI - Study on adsorption process and mechanism of p-nitroaniline on bamboo charcoal AU - Wu, G. AU - Wu, G. AU - Zhang, Q. AU - Knappe, D.R.U. T2 - Chinese Journal of Environmental Engineering DA - 2017/// PY - 2017/// DO - 10.12030/j.cjee.201509119 VL - 11 IS - 1 SP - 251-259 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014384902&partnerID=MN8TOARS ER - TY - CONF TI - Multi-stage stochastic optimization for a PV-storage hybrid unit in a household AU - Hafiz, F. AU - De Queiroz, A.R. AU - Husain, I. AB - In the face of increasing global energy supply challenges, renewable energy sources provide a cleaner and environmentally friendly energy alternative. To address the intermittency in PV power generation, battery storage can be used to store energy during lower demand periods. This requires the charging and discharging routine of the storage system to be controlled to achieve optimal economic benefits. In this paper, coordinated control between PV component and an accompanying storage unit is presented considering the stochastic nature of PV generation. The stochastic dual dynamic programming (SDDP) algorithm is employed to optimize the charge/discharge profiles with the goal to minimize the overall cost of satisfying the daily household load demand. The PV-storage hybrid unit can jointly contribute in reducing the consumer costs as shown through simulation analysis. C2 - 2017/// C3 - 2017 IEEE Industry Applications Society Annual Meeting, IAS 2017 DA - 2017/// DO - 10.1109/IAS.2017.8101704 VL - 2017-January SP - 1-7 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85044105670&partnerID=MN8TOARS ER - TY - JOUR TI - Characterizing Fatigue Failure Behavior of Modified Asphalt Binders from Linear Amplitude Sweep Test AU - Xue, Lei AU - Xie, Wei AU - Wang, Yang AU - Wang, Chao T2 - DEStech Transactions on Materials Science and Engineering AB - The fatigue characteristics of asphalt binder contributes to the fatigue resistance of asphalt concrete and pavements. The linear amplitude sweep (LAS) test (AASHTO TP 101) has been developed as the accelerated testing procedure for fatigue specification of asphalt binders in the United States. Recently a newly energy-based fatigue failure definition and unified failure criterion have been proposed for improving the LAS procedure and data interpreting. However, these new improvements need more verification and calibration on more materials with different modifiers for distinguishing the fatigue performance. In this paper, the improved LAS testing procedure was applied on totally two neat asphalt binders and six modified asphalt binders, which covered the high modulus asphalt binders (HMABs), SBS modified binder, high viscosity (HV) binder and crumb rubber (CR) modified binder. Based on the simplified-viscoelastic continuum damage (S-VECD) modeling approach, three material properties of linear viscoelastic property, damage characteristic curve and failure criterion were characterized for fatigue life prediction of all tested binders. Test results indicates that the CR binder demonstrated the highest failure strain followed by the SBS and compound SBS+HV binders, HMABs and neat binders. Further results of predictive fatigue life also verified the best fatigue life of CR binder followed by SBS+HV binders, SBS binder and HMABs. The HV additives to SBS binder was found to linearly increase the binder fatigue lives and the HMAB-RA showed better fatigue performance than HMAB-PR. Generally, the fatigue life ranking determined from the multiple-loading rates of LAS tests is consistent to the failure strain results and thus, the failure strain identified from the standard LAS-5 test could be used as a fatigue performance parameter. DA - 2017/5/23/ PY - 2017/5/23/ DO - 10.12783/dtmse/ictim2017/9900 VL - 5 IS - ictim J2 - dtmse OP - SN - 2572-889X UR - http://dx.doi.org/10.12783/dtmse/ictim2017/9900 DB - Crossref ER - TY - BOOK TI - Exploring Vehicle–Pedestrian Crash Severity Factors on the Basis of In-Car Black Box Recording Data AU - Song, T.-J. AU - So, J. AU - Lee, J. AU - Williams, B.M. AB - This study investigated the main factors affecting the severity of injury to pedestrians in taxi–pedestrian crashes on urban arterial roads. Video data recorded by an in-car black box were used. Because the video data provided direct crash observation, they were more reliable than the crash data, and video images and speed profiles retrieved from the black box were advantageous for safety studies. For analysis of the black box data, this study defined new explanatory variables that affected injury severity; these variables could not have been identified by the conventional method, which was based on crash reports. A multiple-indicator and multiple-cause model was used to investigate the relationship between the explanatory variables and injury severity. A total of 484 taxi–pedestrian crash scenes over 2 years was used for the multivariate analysis in the city of Incheon, South Korea. The crash characteristics most strongly associated with increased crash severity were failure by the pedestrian to watch for approaching vehicles, jaywalking by the pedestrian, the pedestrian being elderly, excessive vehicle speed, failure by the driver to immediately stop, limited driver vision, and nighttime. This study emphasized the potential of individualized black box video recording data for crash severity analysis and investigation of the causal factors of crashes. DA - 2017/// PY - 2017/// DO - 10.3141/2659-16 VL - 2659 SE - 148-154 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85057965576&partnerID=MN8TOARS ER - TY - CONF TI - Performance in takeover and characteristics of non-driving related tasks during highly automated driving in younger and older drivers AU - Clark, H. AU - McLaughlin, A.C. AU - Williams, B. AU - Feng, J. AB - This paper aims to examine the effect of age and various characteristics of non-driving related activities during highly automated driving on subsequent performance in notified takeovers among younger and older drivers. The paper presents new analyses of data collected in our earlier study (Clark & Feng, 2016). Non-driving-related activities that participants voluntarily chose to engage in during automated driving were categorized according to their cognitive dimensions in information processing. Using hierarchical multiple regressions, we analyzed the effect of driver age, total duration and number of engagement in non-driving-related activities, the duration and cognitive dimensions of the last activity prior to takeover on average speed during takeover and the response time to a takeover notification. We found that older drivers speed was negatively predicted by age while their response time to a notification was not predicted by any factor. In contrast, younger drivers showed a trend of positive relationship between age and average speed and the characteristics of the last task engagement explained a significant portion of the variance of response time to a notification. C2 - 2017/// C3 - Proceedings of the Human Factors and Ergonomics Society DA - 2017/// DO - 10.1177/1541931213601504 VL - 2017-October SP - 37-41 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85042494534&partnerID=MN8TOARS ER - TY - CONF TI - Detailing for Torsion Revisited AU - Collins, M.P. AU - Bentz, E.C. AU - Kuan, A. AU - Proestos, G.T. T2 - Denis Mitchell Symposium C2 - 2017/5/5/ C3 - Denis Mitchell Symposium CY - Montreal, Quebec, Canada DA - 2017/5/5/ PY - 2017/5/5/ ER - TY - JOUR TI - Supplementary material to "Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway" AU - Saha, Provat Kumar AU - Khlystov, Andrey AU - Grieshop, Andrew Patrick DA - 2017/8/11/ PY - 2017/8/11/ DO - 10.5194/acp-2017-690-supplement VL - 8 UR - https://doi.org/10.5194/acp-2017-690-supplement ER - TY - JOUR TI - Review of Sato et al. AU - Grieshop, Andrew DA - 2017/11/11/ PY - 2017/11/11/ DO - 10.5194/acp-2017-860-RC2 VL - 11 UR - https://doi.org/10.5194/acp-2017-860-RC2 ER - TY - JOUR TI - Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway AU - Saha, Provat Kumar AU - Khlystov, Andrey AU - Grieshop, Andrew Patrick AB - Abstract. We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semi-volatile species (SVOCs) in ultrafine particles decreases with downwind distance, consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20–30 % of particle mass as semi-volatile (SVOCs; effective saturation concentration, C* ≥ 1µm−3) at 10 m from road edge, approximately 10 % of particle mass is attributed to SVOCs at 220 m, showing that the particle-phase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle-phase increased during winter. Downwind spatial gradients of the less-volatile particle fraction (that remaining after heating at 180 °C) was strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a Single Particle Soot Photometer (SP2) at the roadside trailer showed that a large fraction (70–80 %) of BC particles were externally-mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the non-volatile fraction in roadside aerosols are mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a few hundred meters from the highway. A preliminary analysis indicates that a super-position of volatility distributions measured in laboratory vehicle tests and of ``background'' aerosol can be used to represent the observed partitioning of near-road particles. The results from this study highlight that exposures and impacts of BC and semi-volatile organics containing particles in a near-road microenvironment may differ across seasons and under changing ambient conditions. DA - 2017/8/11/ PY - 2017/8/11/ DO - 10.5194/acp-2017-690 VL - 8 UR - https://doi.org/10.5194/acp-2017-690 ER - TY - SOUND TI - Development of Photochemical Microsensors for Evaluating Light Distribution within Microalgal Photosynthetic Bioreactors AU - Karam, A.L. AU - Ducoste, J.J. AU - de los Reyes, F.L., III DA - 2017/6/22/ PY - 2017/6/22/ ER - TY - SOUND TI - Integrative Dynamic Modeling Using Diverse Biological Datasets AU - Williams, Cranos AU - Koryachko, Alexandr AU - Matthiadis, Anna AU - Muhammad, Durreshahwar AU - Brady, Siobhan M. AU - Ducoste, Joel AU - Tuck, James AU - Long, Terri A. DA - 2017/6/12/ PY - 2017/6/12/ ER - TY - CONF TI - Physiological responses of microalgae, Dunaliella viridis, during nitrogen–limited growth AU - Lai, Y. C. AU - Karam, A. AU - Ranjithan, R. AU - Levis, J. AU - de los Reyes, F.L., III AU - Ducoste, J. T2 - 7th International Conference on Biofuels, Biomass, and Bioproducts C2 - 2017/6/18/ CY - Miami, FL DA - 2017/6/18/ PY - 2017/6/18/ ER - TY - CONF TI - Quantifying Light Distributions within Microalgal Photosynthetic Bioreactors Using Novel Microsensors AU - Karam, A. AU - Lai, Y.C. AU - Liu, J. AU - Ranjithan, R. AU - Levis, J. AU - de los Reyes, F.L., III AU - Ducoste, J. T2 - 7th International Conference on Biofuels, Biomass, and Bioproducts C2 - 2017/6/18/ CY - Miami, FL DA - 2017/6/18/ PY - 2017/6/18/ ER - TY - SOUND TI - Holy Dish Pan Hands Batman, there are Soaps in the Sewers: Fats, Oil, and Grease Issues in Sewer Systems AU - Ducoste, J.J. DA - 2017/// PY - 2017/// M3 - Seminar ER - TY - SOUND TI - Drinking Water Treatment: What Happens from Source to Tap AU - Ducoste, J.J. DA - 2017/// PY - 2017/// M3 - Seminar ER - TY - SOUND TI - Raising the Value of Water: A strategy for Greater Public Health Protection AU - Ducoste, J.J. DA - 2017/// PY - 2017/// M3 - Seminar ER - TY - MGZN TI - Unintended Consequences of a Local Fats, Oils, and Grease Limits Revisions: One Utilizity’s Experience with FOG AU - Sadler, M. AU - Wischer, B. AU - Gordon, J. AU - Wilkerson, C. AU - Tabor, C. AU - Fredericks, D. AU - Ducoste, J. T2 - Horizons New Letter DA - 2017/8/28/ PY - 2017/8/28/ ER - TY - CONF TI - Quantification of transit train activity data for energy consumption estimation AU - Yuan, W. AU - Frey, H.C. AU - Sun, Y. C2 - 2017/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2017/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039168169&partnerID=MN8TOARS ER - TY - JOUR TI - Benchmarking of energy saving potential and CO2 reduction in iranian compressor stations AU - Sardarmehni, M. AU - Tahouni, N. AU - Panjeshahi, M.H. T2 - Chemical Engineering Transactions DA - 2017/// PY - 2017/// DO - 10.3303/CET1761229 VL - 61 SP - 1387-1392 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85030776137&partnerID=MN8TOARS ER - TY - JOUR TI - Benchmarking of olefin plant cold-end for shaft work consumption, using process integration concepts AU - Sardarmehni, M. AU - Tahouni, N. AU - Panjeshahi, M.H. T2 - Energy AB - The olefin plant is all about separating cracked gas into ethylene, propylene and other heavier by-products using low-temperature gas separation processes. This process is energy-intensive and hence retrofitting for energy saving would be desirable. However, a full retrofit study requires a lot of time and costly engineering work. So, a novel method is introduced in this paper for benchmarking of shaft work consumption in olefin cold-end, which is based on process integration concepts. In developing this method, the amount of shaft work required in refrigeration cycles was first targeted via application of Pinch Analysis to six different olefin plants followed by the calculation of feasible and achievable energy saving potential. When doing so, the effect of predominant factors such as plant capacity, feedstock (naphtha or natural gas), products specification and type of technology being used was investigated as well. Finally, a mathematical model was developed for rapid estimation of energy saving potential using the above key factors. This model was verified through case studies and was proved to be accurate enough for shortcut calculations. DA - 2017/// PY - 2017/// DO - 10.1016/j.energy.2017.03.066 VL - 127 SP - 623-633 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85017099205&partnerID=MN8TOARS KW - Olefin cold-end KW - Pinch technology KW - Energy consumption model KW - Energy benchmarking KW - CO2 reduction ER - TY - CONF TI - An Experimental and Numerical Study of Hydronic Asphalt Pavements AU - Saleh, N.F. AU - Zalghout, A. AU - Din, S.Sari Ad AU - El-Khatib, A. AU - Saleh, K. T2 - 16th Faculty of Engineering and Architecture Student and Alumni Conference C2 - 2017/// CY - Beirut, Lebanon DA - 2017/// PY - 2017/4// ER - TY - JOUR TI - Evaluation of asphalt mixture laboratory long-term ageing methods for performance testing and prediction AU - Elwardany, Michael D. AU - Yousefi Rad, Farhad AU - Castorena, Cassie AU - Kim, Y. Richard T2 - Road Materials and Pavement Design AB - Ageing has long been recognised as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Ageing causes the material to stiffen and embrittle, which leads to a high potential for cracking. Although a significant amount of effort has been placed on understanding the ageing process of asphalt binder, less effort has been put forth to develop laboratory ageing procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term ageing for performance testing and prediction is required in order to integrate the effects of long-term ageing in pavement prediction models and other mechanistic design and analysis methods. In this study, oven ageing and pressure ageing vessel ageing are applied to both loose mix and compacted specimens in order to evaluate and select an ageing method to simulate long-term ageing for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the ageing methods. The results demonstrate that loose mix ageing in an oven is the most promising ageing method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost. DA - 2017/// PY - 2017/// DO - 10.1080/14680629.2016.1266740 VL - 18 IS - sup1 SP - 28–61 SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2016.1266740 KW - long-term ageing KW - ageing index properties KW - loose mix ageing ER - TY - JOUR TI - A Review of the Environmental Releases from Uncontrolled Solid Waste Disposal Sites AU - Levis, J.W. AU - Weisbrod, A. AU - Van Hoof, G. AU - Barlaz, M.A. T2 - Critical Reviews in Environmental Science and Technology DA - 2017/// PY - 2017/// VL - 47 IS - 12 SP - 1003 – 1041 ER - TY - SOUND TI - The Use of Landfills for the Long-Term Storage of Biogenic Organic Carbon AU - Barlaz, M.A. DA - 2017/// PY - 2017/// ER - TY - SOUND TI - A Model to Describe Heat Accumulation at Municipal Solid Waste Landfills AU - Barlaz, M.A. DA - 2017/// PY - 2017/// M3 - oral speech ER - TY - JOUR TI - National Inventory of Per- and Polyfluoroalkyl Substances (PFASs) in U.S. Municipal Landfill Leachate AU - Lang, J.R. AU - Allred, B.M. AU - Field, J.A. AU - Levis, J.W. AU - Barlaz, M.A. T2 - Environmental Science & Technology DA - 2017/// PY - 2017/// VL - 51 IS - 4 SP - 2197 – 2205 ER - TY - CONF TI - A Model to Describe Heat Generation and Accumulation in Municipal Solid Waste Landfills AU - Barlaz, M.A. T2 - US EPA Workshop on Understanding Heat Generation at Municipal Solid Waste Landfills C2 - 2017/// CY - Cincinnati, OH DA - 2017/// PY - 2017/4/19/ ER - TY - CONF TI - Why Do Waste Transfer Station Concrete Floors Deteriorate Prematurely? AU - Park, S. AU - Pour-Ghaz, M. AU - Castellano, L. AU - Barlaz, M. T2 - Open Topic Paper Session, American Concrete Institute, Fall 2017 Convention C2 - 2017/// CY - Anaheim, CA DA - 2017/// PY - 2017/10/15/ ER - TY - CONF TI - Life Cycle Modeling to Support Waste Management Planning AU - Barlaz, M.A. AU - Levis, J.W. AU - Roberson, J. T2 - NC Solid Waste Association of North America Annual Meeting C2 - 2017/// CY - Raleigh, NC DA - 2017/// PY - 2017/10/31/ ER - TY - CONF TI - What are the Best Values for Carbon Dissimilation Factors for Landfilled Harvested Wood Products? AU - Wang, X. AU - Huang, K. AU - Wei, X. AU - Barlaz, M.A. T2 - 16th International Waste Management and Landfill Symposium C2 - 2017/// CY - S. Margherita di Pula (CA), Italy DA - 2017/// PY - 2017/10/2/ ER - TY - CONF TI - Microbial Population Development during the Anaerobic Decomposition of Food Waste AU - Lee, E. AU - Reyes, F. AU - Barlaz, M.A. T2 - Association. of Environmental Science. and Engineering Professors Biannual Research and Education Conference C2 - 2017/// CY - Ann Arbor, MI DA - 2017/// PY - 2017/6/20/ ER - TY - SOUND TI - Utilizing Climate Information for Improving Water, Energy, & Ecological Management AU - Arumugam, S. DA - 2017/4/20/ PY - 2017/4/20/ ER - TY - SOUND TI - Uncertainty Reduction in Climate Forecasts using Multimodel Combination and their Relevance to Water and Energy Management AU - Arumugam, S. DA - 2017/3/16/ PY - 2017/3/16/ ER - TY - SOUND TI - Decomposition of Sources of Errors in Seasonal Streamflow Forecasting over the US Sunbelt AU - Arumugam, S. DA - 2017/7/13/ PY - 2017/7/13/ ER - TY - CONF TI - Data Assimilation using observed streamflow and remotely-sensed soil moisture for improving sub-seasonal-to-seasonal forecasting AU - Mazrooei, A. AU - Arumugam, S. AU - Lakshmi, V. AU - Wood, A. T2 - American Geophysical Union Fall meeting C2 - 2017/12/11/ CY - New Orleans, LA DA - 2017/12/11/ PY - 2017/12/11/ ER - TY - CONF TI - Equivalent Reservoir Modeling for Multipurpose and Multi-reservoir Systems over the Southern United States AU - Mukhopadhyaya, S. AU - Quieroz, A. AU - Arumugam, S. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2017/5/21/ CY - Sacramento, CA DA - 2017/5/21/ PY - 2017/5/21/ ER - TY - CONF TI - Sub-seasonal-to-seasonal Reservoir Inflow Forecast using Bayesian Hierarchical Hidden Markov Model AU - Mukhopadhyaya, S. AU - Arumugam, S. T2 - American Geophysical Union Fall meeting C2 - 2017/12/11/ CY - New Orleans, LA DA - 2017/12/11/ PY - 2017/12/11/ ER - TY - CONF TI - Impact of Correlation Between Precipitation and Temperature on Hydrologic Simulations AU - Seo, S.B. AU - Bhowmik, R. Das AU - Mahinthakumar, G. AU - Arumugam, S. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2017/5/21/ CY - Sacramento, CA DA - 2017/5/21/ PY - 2017/5/21/ ER - TY - CONF TI - Multivariate Bias Correction Procedures for Improving Water Quality Predictions from the SWAT Model AU - Libera, D. AU - Arumugam, S. T2 - American Geophysical Union Fall meeting C2 - 2017/12/11/ CY - New Orleans, LA DA - 2017/12/11/ PY - 2017/12/11/ ER - TY - CONF TI - A Hybrid Approach Towards Streamflow Reconstruction Using Tree-ring Chronologies and Ssts over the United States AU - Patskoski, J.S. AU - Mukhopadhyaya, S. AU - Arumugam, S. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2017/5/21/ CY - Sacramento, CA DA - 2017/5/21/ PY - 2017/5/21/ ER - TY - CONF TI - Integrated Drought Monitoring and Forecasts for Decision Making in Water and Agricultural Sectors over the Southeastern US under Changing Climate AU - Arumugam, S. AU - Mazrooei, A. AU - Cumbie-Ward, R. T2 - American Geophysical Union Fall meeting C2 - 2017/12/11/ CY - New Orleans, LA DA - 2017/12/11/ PY - 2017/12/11/ ER - TY - CONF TI - Utilizing Enkf Data Assimilation in Improving ‘abcd’ Lumped Water Balance Model Performance AU - Mazrooei, A. AU - Arumugan, S. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2017/5/21/ CY - Sacramento, CA DA - 2017/5/21/ PY - 2017/5/21/ ER - TY - RPRT TI - Climate Informed Uncertainty Analyzes for Integrated Water Resources Sustainability AU - Sankarasubramanian, A. A3 - National Science Foundation DA - 2017/// PY - 2017/// M3 - Technical Report PB - National Science Foundation ER - TY - JOUR TI - Reliability based inspection planning using fracture mechanics based fatigue evaluations for ship structural details AU - Doshi, Karan AU - Roy, Tuhin AU - Parihar, Yogendra Singh T2 - Marine Structures AB - Survey and inspection of ship structures is essential in order to monitor the integrity of the hull. With increasing ship size, the number of details susceptible to fatigue damage may be significant. Also as the ship nears the end of its design life, more effective inspections are required to ascertain the structural health of the ship. Reliability based inspection techniques are a possible way for ensuring the effectiveness of the surveys. In the present work, the applications of fracture mechanics based fatigue crack evaluations have been demonstrated to prepare reliability based inspection plans for a Very Large Crude Carrier (VLCC). Probabilistic considerations have been applied taking into account the uncertainty in various parameters related to the loads, materials as well as the parameters of fatigue crack growth. Scheme for updating of reliability of a given ship structural detail has been presented which employs Bayesian approach. Effect of utilization of various inspection techniques has been demonstrated. Various cases such as no-detection of crack, detection of crack with & without repair have been considered. Finally, the results have been also compared with the reliabilities in the current practice of fixed periodical inspections. The paper demonstrates that reliability based inspections are a feasible technique for integrity management of ship structural details while maintaining a practicable work schedule. DA - 2017/7// PY - 2017/7// DO - 10.1016/j.marstruc.2017.03.003 VL - 54 SP - 1-22 J2 - Marine Structures LA - en OP - SN - 0951-8339 UR - http://dx.doi.org/10.1016/j.marstruc.2017.03.003 DB - Crossref KW - Fracture mechanics KW - Fatigue KW - Ship structure details KW - Inspection planning KW - S-N curve KW - Bayesian updating KW - Reliability index KW - Probability of detection ER - TY - CONF TI - Effect of Road Roughness and Vehicle Speed on Dynamic Load Prediction and Pavement Performance Reduction AU - Goenaga Silvera, Boris AU - Fuentes, Luis G. AU - Mora, Otto T2 - Transportation Research Board 96th Annual Meeting C2 - 2017/// C3 - Proceedings of the Transportation Research Board 96th Annual Meeting CY - Washington, DC DA - 2017/// PY - 2017/1/8/ ER - TY - JOUR TI - Evaluation of the methodologies used to generate random pavement profiles based on the power spectral density: An approach based on the international roughness index | Análisis de las metodologías utilizadas para generar perfiles aleatorios de pavimento con base en la densidad espectral de potencia (DEP): Un enfoque ajuste basado en el índice de rugosidad internacional AU - Goenaga, B. AU - Fuentes, L. AU - Mora, O. T2 - Ingenieria e Investigacion AB - The pavement roughness is the main variable that produces the vertical excitation in vehicles. Pavement profiles are the main determinant of (i) discomfort perception on users and (ii) dynamic loads generated at the tire-pavement interface, hence its evaluation constitutes an essential step on a Pavement Management System. The present document evaluates two specific techniques used to simulate pavement profiles; these are the shaping filter and the sinusoidal approach, both based on the Power Spectral Density. Pavement roughness was evaluated using the International Roughness Index (IRI), which represents the most used index to characterize longitudinal road profiles. Appropriate parameters were defined in the simulation process to obtain pavement profiles with specific ranges of IRI values using both simulation techniques. The results suggest that using a sinusoidal approach one can generate random profiles with IRI values that are representative of different road types, therefore, one could generate a profile for a paved or an unpaved road, representing all the proposed categories defined by ISO 8608 standard. On the other hand, to obtain similar results using the shaping filter approximation a modification in the simulation parameters is necessary. The new proposed values allow one to generate pavement profiles with high levels of roughness, covering a wider range of surface types. Finally, the results of the current investigation could be used to further improve our understanding on the effect of pavement roughness on tire pavement interaction. The evaluated methodologies could be used to generate random profiles with specific levels of roughness to assess its effect on dynamic loads generated at the tire-pavement interface and user’s perception of road condition. DA - 2017/// PY - 2017/// DO - 10.15446/ing.investig.v37n1.57277 VL - 37 IS - 1 SP - 49-57 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85018704400&partnerID=MN8TOARS KW - Random process KW - power spectral pensity KW - sinusoidal approximation KW - shaping filter KW - pavement profile KW - roughness ER - TY - JOUR TI - Structural equation modeling of user satisfaction of bus transit service quality based on stated preferences and latent variables AU - Hadiuzzman, Md AU - Das, Tanmay AU - Hasnat, Md Mehedi AU - Hossain, Sanjana AU - Rafee Musabbir, Sarder T2 - Transportation Planning and Technology DA - 2017/// PY - 2017/// VL - 40 IS - 3 SP - 257-277 ER - TY - CONF TI - Ground Motions from the August 24, 2016 Rieti Earthquake in Italy AU - Chowdhury, I.C. AU - Cabas, A. T2 - Geotechnical Frontiers 2017 Conference C2 - 2017/// CY - Orlando, Florida DA - 2017/// PY - 2017/3/12/ ER - TY - CONF TI - Life Cycle Environmental Impacts of using Lithium Ion Batteries for Power System Reserves and Strategies for Mitigation AU - Ryan, N.A. AU - Lin, Y. AU - Mitchell-Ward, N. AU - Mathieu, J.L. AU - Johnson, J.X. T2 - 2017 AEESP Research and Education Conference C2 - 2017/// C3 - Proceedings of 2017 AEESP Research and Education Conference CY - Ann Arbor, MI DA - 2017/// PY - 2017/6/20/ ER - TY - CONF TI - Estimation of Site-Specific Kappa (κ0)-Consistent Damping Values at Selected Stations from the KiK-net Database AU - Cabas, A. AU - Rodriguez-Marek, A. T2 - 2017 SSA Annual Meeting C2 - 2017/// CY - Denver, Colorado DA - 2017/// PY - 2017/4/18/ ER - TY - RPRT TI - An empirical study of the parameterization of site response using the KiKnet array AU - Rodriguez-Marek, A. AU - Dawood, H.M. AU - Upadhyaya, S. AU - Cabas, A. DA - 2017/4// PY - 2017/4// M1 - G14AP00017 M3 - USGS Report SN - G14AP00017 ER - TY - CONF TI - What Can We Learn from Kappa (k) to Achieve a Better Characterization of Damping in Geotechnical Site Response Models? AU - Cabas, A. AU - Rodriguez-Marek, A. T2 - ASCE Geotechnical Frontiers 2017 Conference AB - Site response analyses (SRA) provide a means to assess the seismic wave propagation phenomenon in shallow deposits and capture its influence on ground motions. One of the key model assumptions in SRA involves the characterization of the attenuation at the site. Typical damping models are developed by testing small-scale soil samples in the laboratory. These procedures can only characterize material damping and fail to capture other sources of attenuation as they occur in the field (e.g., scattering). The spectral decay parameter, kappa, is used in this study to define alternative damping models. These combined models of geotechnical and seismological attenuation descriptors provide larger estimates of damping than laboratory-based models. The most important practical application of this study is the definition of the portion of attenuation that is ignored when solely relying in dynamic laboratory testing. Insights on similarities between kappa and damping values used in geotechnical models are also provided. C2 - 2017/// C3 - Geotechnical Frontiers: Seismic Performance and Liquefaction CY - Orlando, Florida DA - 2017/// PY - 2017/3/12/ DO - 10.1061/9780784480489.001 PB - ASCE Geotechnical Special Publication ER - TY - JOUR TI - Significance of non-classical damping in seismic qualification of equipment and piping AU - Gupta, Abhinav AU - Bose, Mrinal K. T2 - Nuclear Engineering and Design AB - This paper presents a discussion on the significance of non-classical damping in coupled primary-secondary systems such as building-equipment or building-piping. Closed-form expressions are used to illustrate that the effect of non-classical damping is significant in systems with tuned or nearly tuned uncoupled modes when the mass-interaction is sufficiently small. Further, simple primary-secondary systems are used to illustrate that composite modal damping is another form of classical damping for which the transformed damping matrix, obtained after pre- and post-multiplication of the damping matrix with the modal matrix, contains only diagonal terms. Both the composite and the classical damping give almost identical results that can be much different from the corresponding results for non-classical damping. Finally, it is shown that consideration of classical damping (ignoring the off-diagonal terms) can give excessively conservative results in nearly tuned primary-secondary systems. For perfectly tuned primary-secondary systems, however, classical damping can give responses that are much lower than what they should be. DA - 2017/6// PY - 2017/6// DO - 10.1016/J.NUCENGDES.2017.03.020 VL - 317 SP - 90-99 J2 - Nuclear Engineering and Design LA - en OP - SN - 0029-5493 UR - http://dx.doi.org/10.1016/J.NUCENGDES.2017.03.020 DB - Crossref KW - Non-classical damping KW - Classical damping KW - Composite modal damping KW - Floor spectra KW - Seismic qualification ER - TY - CONF TI - Shearing and Hydraulic Behavior of MICP Treated Silty Sand AU - Zamani, Atefeh AU - Montoya, Brina M. T2 - Geotechnical Frontiers 2017 AB - Microbial induced calcite precipitation (MICP) is a biochemical reaction that takes place within the soil producing calcite cementation bonding soil grains together. In this study, MICP method was applied to both Nevada sand and Nevada sand containing 15% silt to assess their improvement in monotonic shear strength, cyclic resistance and also changes in permeability. The change in shear strength properties are evaluated by performing undrained monotonic and cyclic direct simple shear tests on both treated and untreated samples. Reduction in permeability as a result of calcite precipitation is also another objective of this research which is investigated by performing constant head tests on untreated and MICP treated samples. The results show improvement in shear response and reduction in excess pore water pressure in both treated samples. The cyclic resistance also increases by applying MICP. The permeability of soil reduces by applying MICP but the amount of reduction is low in comparison to the change in permeability when fines are added to the Nevada sand. C2 - 2017/3/30/ C3 - Geotechnical Frontiers 2017 DA - 2017/3/30/ DO - 10.1061/9780784480489.029 PB - American Society of Civil Engineers SN - 9780784480489 UR - http://dx.doi.org/10.1061/9780784480489.029 DB - Crossref ER - TY - JOUR TI - Formalizing best practice for energy system optimization modelling AU - DeCarolis, Joseph AU - Daly, Hannah AU - Dodds, Paul AU - Keppo, Ilkka AU - Li, Francis AU - McDowall, Will AU - Pye, Steve AU - Strachan, Neil AU - Trutnevyte, Evelina AU - Usher, Will AU - Winning, Matthew AU - Yeh, Sonia AU - Zeyringer, Marianne T2 - Applied Energy AB - Energy system optimization models (ESOMs) are widely used to generate insight that informs energy and environmental policy. Using ESOMs to produce policy-relevant insight requires significant modeler judgement, yet little formal guidance exists on how to conduct analysis with ESOMs. To address this shortcoming, we draw on our collective modelling experience and conduct an extensive literature review to formalize best practice for energy system optimization modelling. We begin by articulating a set of overarching principles that can be used to guide ESOM-based analysis. To help operationalize the guiding principles, we outline and explain critical steps in the modelling process, including how to formulate research questions, set spatio-temporal boundaries, consider appropriate model features, conduct and refine the analysis, quantify uncertainty, and communicate insights. We highlight the need to develop and refine formal guidance on ESOM application, which comes at a critical time as ESOMs are being used to inform national climate targets. DA - 2017/5// PY - 2017/5// DO - 10.1016/J.APENERGY.2017.03.001 VL - 194 SP - 184-198 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/J.APENERGY.2017.03.001 DB - Crossref KW - Energy system models KW - Uncertainty KW - Modelling guidance ER - TY - JOUR TI - Repeated healing of delamination damage in vascular composites by pressurized delivery of reactive agents AU - Hart, Kevin R. AU - Lankford, Seth M. AU - Freund, Isaac A. AU - Patrick, Jason F. AU - Krull, Brett. P. AU - Wetzel, Eric D. AU - Sottos, Nancy R. AU - White, Scott R. T2 - Composites Science and Technology AB - Recurrent self-healing of fracture damage in fiber-reinforced composites was accomplished by incorporating internal vascular networks for repeated delivery of reactive liquid components to an internal delamination. Double cantilever beam specimens containing embedded microvascular channels were repeatedly fractured and healed by pumping individually sequestered epoxy and amine based healing agents to the fracture plane. The effect of various pumping parameters and component delivery ratios on in situ mixing of the healing agents and the resulting healing efficiency is reported. Confocal Raman spectroscopy was used to quantify the extent of mixing of healing agents within the fracture plane. Using an optimized healing agent delivery scheme, ten cycles of fracture and healing were achieved with, on average, 55% and as high as 95%, recovery of the virgin critical strain energy release rate. DA - 2017/10// PY - 2017/10// DO - 10.1016/J.COMPSCITECH.2017.07.027 VL - 151 SP - 1-9 J2 - Composites Science and Technology LA - en OP - SN - 0266-3538 UR - http://dx.doi.org/10.1016/J.COMPSCITECH.2017.07.027 DB - Crossref KW - Self-healing KW - Vascular KW - Fiber-reinforced composites KW - Raman spectroscopy ER - TY - JOUR TI - Driver performance and attention allocation in use of logo signs on freeway exit ramps AU - Zahabi, Maryam AU - Machado, Patricia AU - Lau, Mei Ying AU - Deng, Yulin AU - Pankok, Carl, Jr. AU - Hummer, Joseph AU - Rasdorf, William AU - Kaber, David B. T2 - Applied Ergonomics AB - The objective of this research was to quantify the effects of driver age, ramp signage configuration, including number of panels, logo format and sign familiarity, on driver performance and attention allocation when exiting freeways. Sixty drivers participated in a simulator study and analysis of variance models were used to assess response effects of the controlled manipulations. Results revealed elderly drivers to demonstrate worse performance and conservative control strategies as compared to middle-aged and young drivers. Elderly drivers also exhibited lower off-road fixation frequency and shorter off-road glance durations compared to middle-aged and young drivers. In general, drivers adopted a more conservative strategy when exposed to nine-panel signs as compared to six-panel signs and were more accurate in target detection when searching six-panels vs. nine and with familiar vs. unfamiliar logos. These findings provide an applicable guide for agency design of freeway ramp signage accounting for driver demographics. DA - 2017/11// PY - 2017/11// DO - 10.1016/J.APERGO.2017.06.001 VL - 65 SP - 70-80 J2 - Applied Ergonomics LA - en OP - SN - 0003-6870 UR - http://dx.doi.org/10.1016/J.APERGO.2017.06.001 DB - Crossref KW - Roadway logo signs KW - Driving simulation KW - Exit ramp KW - Driver distraction KW - Highway safety ER - TY - JOUR TI - The role of driver age in performance and attention allocation effects of roadway sign count, format and familiarity AU - Zahabi, Maryam AU - Machado, Patricia AU - Pankok, Carl, Jr. AU - Lau, Mei Ying AU - Liao, Yi-Fan AU - Hummer, Joseph AU - Rasdorf, William AU - Kaber, David B. T2 - Applied Ergonomics AB - White-on-blue logo signs are used to inform drivers of food, gas, lodging, and attraction businesses at highway interchanges. In this study, 60 drivers were asked to look for food and attraction targets on logo signs while driving in a realistic freeway simulation. The objective of the study was to quantify effects of the number of sign panels (six vs. nine), logo familiarity (familiar vs. unfamiliar), logo format (text vs. pictorial), and driver age (young, middle, and elderly) on performance, attention allocation and target identification accuracy. Results revealed elderly drivers to exhibit worse performance in comparison to middle-age and young groups even though they adopted a more conservative driving strategy. There was no significant effect of the number of panels, logo familiarity, and logo format on driver performance or attention allocation. In target identification, drivers were more accurate with familiar or text-based panels appearing in six-panel signs. DA - 2017/9// PY - 2017/9// DO - 10.1016/J.APERGO.2017.04.001 VL - 63 SP - 17-30 J2 - Applied Ergonomics LA - en OP - SN - 0003-6870 UR - http://dx.doi.org/10.1016/J.APERGO.2017.04.001 DB - Crossref KW - Logo signs KW - Driving simulation KW - Driver performance KW - Driver distraction KW - Highway safety ER - TY - CONF TI - Deformation Monitoring for the Assessment of Sacramento Delta Levee Performance AU - Bennett, Victoria AU - Jones, Cathleen AU - Bekaert, David AU - Bond, Jason AU - Helal, Amr AU - Dudas, Joel AU - Gabr, Mohammed AU - Abdoun, Tarek T2 - Geo-Risk 2017 AB - The Sacramento Delta levee network plays a vital role in supporting the United States’ largest agricultural production and the municipal water supply for millions of people. Beyond the potential for earthquake-induced failure, performance monitoring of the levee system on the network level and the assessment of potential distress levels are needed for the maintenance and rehabilitation of this system. In this case, critical deformation needs to be assessed especially in view of the levees age, sea level rise, and ongoing subsidence due to the decomposition of the peat foundation layer. The work presented herein describes the remote sensing of a levee section deformation with time. The levee section is located on Sherman Island, CA, and monitoring was conducted in situ by GPS, in addition to remote sensing by airborne synthetic aperture radar and satellite systems. Coupled deformation/seepage numerical analysis of the levee section is performed using PLAXIS. The numerical model included characterization of the unsaturated-saturated zones and the peat foundation layer. Key parameters of the peat layer were synthesized from published data to provide baseline assessment for the current condition of the levee system in view of the measured rate of deformation. C2 - 2017/6// C3 - Geo-Risk 2017 DA - 2017/6// DO - 10.1061/9780784480717.003 PB - American Society of Civil Engineers SN - 9780784480717 UR - http://dx.doi.org/10.1061/9780784480717.003 DB - Crossref ER - TY - JOUR TI - Approach for Estimating Effective Friction Angle from Cone Penetration Test in Unsaturated Residual Soils AU - Tang, Chien-Ting AU - Borden, Roy H. AU - Gabr, Mohammed A. T2 - Journal of Geotechnical and Geoenvironmental Engineering AB - This paper proposes approaches to estimate effective friction angle from cone tip resistance with incorporation of matric suction. Cone penetration tests (CPTs) are performed in unsaturated residual soil layers, where matric suction is measured with depth. Unsaturated triaxial testing is performed on retrieved samples adjacent to the CPT soundings. In addition, the proposed model incorporates a more robust stress state through the use of coefficient of earth pressure at rest (K0) and overconsolidation ratio (OCR). Results indicate that reducing the CPT tip resistance data without incorporating the matric suction effect leads to 6–9° overestimations of the friction angle (the matric suction was approximately 80–90 kPa in type MH soil). The incorporation of a more representative stress state using the mean effective stress in the CPT data reduction leads to a 2–3° reduction of the estimated friction angle compared with traditional approaches for OCR values equal to or greater than 2. DA - 2017/11// PY - 2017/11// DO - 10.1061/(ASCE)GT.1943-5606.0001799 VL - 143 IS - 11 SP - 04017087 J2 - J. Geotech. Geoenviron. Eng. LA - en OP - SN - 1090-0241 1943-5606 UR - http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001799 DB - Crossref ER - TY - JOUR TI - Policy and market barriers to energy storage providing multiple services AU - Forrester, Sydney P. AU - Zaman, Ansha AU - Mathieu, Johanna L. AU - Johnson, Jeremiah X. T2 - The Electricity Journal AB - Policy and market conditions remain the primary barriers to stacking energy storage services, reducing its cost-competitiveness with traditional technologies. This article explores two cases that show how treating energy storage as a traditional asset class providing either market-remunerated or regulated services limits its profitability, and how changing market rules creates regulatory risk that could be mitigated through stacking services. DA - 2017/11// PY - 2017/11// DO - 10.1016/J.TEJ.2017.10.001 VL - 30 IS - 9 SP - 50-56 J2 - The Electricity Journal LA - en OP - SN - 1040-6190 UR - http://dx.doi.org/10.1016/J.TEJ.2017.10.001 DB - Crossref ER - TY - JOUR TI - Effect of cold temperatures on the behavior and ultimate capacity of GFRP-reinforced concrete beams AU - Berry, Michael AU - Johnson, Jeremiah AU - McDevitt, Kate T2 - Cold Regions Science and Technology AB - Abstract This study evaluated the effects of subfreezing temperatures on the behavior and ultimate capacity of GFRP-reinforced concrete beams. Duplicate beam specimens at four temperatures (20 °C, 0 °C, − 20°C, and − 40 °C) were tested in four-point bending until failure, while monitoring applied load and resulting deflection. The ultimate capacity of the beams was observed to increase with decreasing temperature, a result attributed to the effects of temperature on the compressive and tensile capacities of the concrete. Further, the increased tensile capacity of the concrete with decreasing temperature caused a noted difference in the post-cracking response of the beams: an increase in magnitude of drops in the force-deflection response associated with cracking. The method proposed by ACI 440 (2006) for calculating the ultimate capacity of GFRP reinforced beams accurately predicted the capacity of the beams in this investigation, with an average measured to predicted ratio 1.00 using the measured concrete properties and 1.03 using the design concrete properties. DA - 2017/4// PY - 2017/4// DO - 10.1016/J.COLDREGIONS.2017.01.003 VL - 136 SP - 9-16 J2 - Cold Regions Science and Technology LA - en OP - SN - 0165-232X UR - http://dx.doi.org/10.1016/J.COLDREGIONS.2017.01.003 DB - Crossref KW - Cold effects KW - Glass fiber reinforced polymer bars KW - GFRP KW - Concrete ER - TY - CONF TI - Innovation Self-Efficacy: A Very Brief Measure for Engineering Students. AU - Schar, Mark AU - Gilmartin, S AU - Harris, A AU - Rieken, B AU - Sheppard, S C2 - 2017/// C3 - Proceedings for the American Society for Engineering Education Annual Conference, June 25-28. Columbus, OH. DA - 2017/// ER - TY - CONF TI - Professional Engineering Pathways Study: Using a community of practice model to propagate findings and engage the community AU - Streveler, Ruth A AU - Matusovich, Holly M AU - Carrico, Cheryl PE AU - Brunhaver, Samantha AU - Sheppard, Sheri AU - Chen, Helen L AU - Harris, Angela AU - Abhyankar, Rohini AU - Sama, Mitikaa C2 - 2017/// C3 - ASEE Annual Conference and Exposition, Conference Proceedings DA - 2017/// VL - 2017 ER - TY - CONF TI - Understanding Engineering Student Motivating Factors for Job Application and Selection. AU - Harris, Angela AU - Gilmartin, Shannon AU - Reinders, Katherine AU - Sheppard, Sheri C2 - 2017/// C3 - Proceedings of the American Society for Engineering Education Annual Conference, June 25-28. Columbus, OH. DA - 2017/// ER - TY - JOUR TI - Designing a longitudinal study of engineering students’ innovation and engineering interests and plans: The Engineering Majors Survey Project. EMS 1.0 and 2.0 Technical Report AU - Gilmartin, Shannon K AU - Chen, Helen L AU - Schar, Mark F AU - Jin, Qu AU - Toye, George AU - Harris, A AU - Cao, Emily AU - Costache, Emanuel AU - Reithmann, Maximillian AU - Sheppard, Sheri D T2 - Stanford University Designing Education Lab, Stanford, CA, Technical Report DA - 2017/// PY - 2017/// ER - TY - CONF TI - Board# 138: Professional Engineering Pathways Study: Using a Community of Practice Model to Propagate Findings and Engage the Community AU - Streveler, Ruth A AU - Matusovich, Holly M AU - Cheryl Carrico, PE AU - Brunhaver, Samantha Ruth AU - Sheppard, Sheri AU - Chen, Helen L AU - Harris, Angela AU - Abhyankar, Rohini AU - Sama, Mitikaa C2 - 2017/// C3 - 2017 ASEE Annual Conference & Exposition DA - 2017/// ER - TY - JOUR TI - Autonomous Vehicles AU - Noorvand, Hossein AU - Karnati, Guru AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - With ongoing technological improvements and research in the field of autonomous vehicles, it is becoming evident that the technology has the potential to substantially affect the transportation sector. Although the potential benefits with respect to productivity increases, cost decreases, and safety are evident, the potential for these vehicles to negatively or positively affect the transportation infrastructure is unclear. In this study, the influence of truck loadings positioning on the long-term performance of transportation infrastructure was estimated by carrying out performance simulations of pavement structures. Scenarios considering both full and partial use by autonomous trucks were considered. In all cases, performance was estimated with respect to rutting, fatigue cracking, and overall pavement smoothness, and the results were compiled in terms of reduced pavement thickness. It was found that if controlled appropriately, autonomous trucks could be highly beneficial for the pavement infrastructure design, and they would be most effective when they represented more than 50% of the total truck traffic. It was also found that in the absence of appropriate control, specifically by repeatedly positioning trucks in the same location, the amount of damage could be highly detrimental, and noticeable influences may occur at autonomous truck volumes as low as 10%. DA - 2017/1// PY - 2017/1// DO - 10.3141/2640-03 VL - 2640 IS - 1 SP - 21-28 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2640-03 DB - Crossref ER - TY - JOUR TI - Impact of Alternative Project Delivery Systems on the International Roughness Index: Case Studies of Transportation Projects in the Western United States AU - Abkarian, Hoseb AU - El Asmar, Mounir AU - Underwood, Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The impact of alternative project delivery methods (APDM) was compared with that of the traditional method of design–bid–build (DBB) on the long-term performance of transportation projects. The metric used to quantify long-term performance differences between projects is the international roughness index (IRI), which is an indicator of ride quality. Data were collected on four alternative delivery projects on the National Highway System in Arizona and Colorado, along with data on their comparable DBB projects. Two of the projects provided northbound and southbound data and their respective comparisons, so six pairs of projects were investigated. In the study of the IRI time series, five of the six APDM projects were found to perform better than their traditional counterparts. This exploratory study contributes to the body of knowledge by starting to quantify the impact of APDM on the actual long-term performance of transportation projects. DA - 2017/1// PY - 2017/1// DO - 10.3141/2630-10 VL - 2630 IS - 1 SP - 76-84 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2630-10 DB - Crossref ER - TY - JOUR TI - Micromechanical shear modulus modeling of activated crumb rubber modified asphalt cements AU - Medina, Jose R. AU - Underwood, B. Shane T2 - Construction and Building Materials AB - Abstract The rheological properties of three asphalt cements containing reacted and activated rubber (RAR) are evaluated to quantify the relative effects of swelling, splitting, and absorption. Rheological testing and electron microscopy are used to measure the dynamic shear modulus, |G∗|, and rubber particle changes respectively. It is found that |G∗| increased for all RAR and that particles swell 15.8–49.3% with those in softer asphalt showing the greatest swelling. Micromechanical models are used to predict |G∗| of the materials. The Hashin and Christensen models are found to accurately predict the measured moduli after accounting for the swelling, splitting, and absorption. DA - 2017/9// PY - 2017/9// DO - 10.1016/j.conbuildmat.2017.05.208 VL - 150 SP - 56-65 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/j.conbuildmat.2017.05.208 DB - Crossref KW - Crumb rubber KW - Rheology KW - Modified binder KW - Activated rubber KW - Activated mineral binder stabilizer (AMBS) KW - Crumb rubber splitting KW - Composite models KW - Micromechanical models ER - TY - JOUR TI - Increased costs to US pavement infrastructure from future temperature rise AU - Underwood, B. Shane AU - Guido, Zack AU - Gudipudi, Padmini AU - Feinberg, Yarden T2 - Nature Climate Change AB - The selection of materials for road construction in the United States is based on assumptions of a stationary climate. With increasing temperatures, upholding these practices could add up to US$26.3 billion in US-wide maintenance costs by 2040 under RCP8.5. Roadway design aims to maximize functionality, safety, and longevity1,2. The materials used for construction, however, are often selected on the assumption of a stationary climate1,3. Anthropogenic climate change may therefore result in rapid infrastructure failure and, consequently, increased maintenance costs, particularly for paved roads where temperature is a key determinant for material selection. Here, we examine the economic costs of projected temperature changes on asphalt roads across the contiguous United States using an ensemble of 19 global climate models forced with RCP 4.5 and 8.5 scenarios. Over the past 20 years, stationary assumptions have resulted in incorrect material selection for 35% of 799 observed locations. With warming temperatures, maintaining the standard practice for material selection is estimated to add approximately US$13.6, US$19.0 and US$21.8 billion to pavement costs by 2010, 2040 and 2070 under RCP4.5, respectively, increasing to US$14.5, US$26.3 and US$35.8 for RCP8.5. These costs will disproportionately affect local municipalities that have fewer resources to mitigate impacts. Failing to update engineering standards of practice in light of climate change therefore significantly threatens pavement infrastructure in the United States. DA - 2017/9/18/ PY - 2017/9/18/ DO - 10.1038/nclimate3390 VL - 7 IS - 10 SP - 704-707 J2 - Nature Clim Change LA - en OP - SN - 1758-678X 1758-6798 UR - http://dx.doi.org/10.1038/nclimate3390 DB - Crossref ER - TY - JOUR TI - Fail-safe and safe-to-fail adaptation: decision-making for urban flooding under climate change AU - Kim, Yeowon AU - Eisenberg, Daniel A. AU - Bondank, Emily N. AU - Chester, Mikhail V. AU - Mascaro, Giuseppe AU - Underwood, B. Shane T2 - Climatic Change AB - As climate change affects precipitation patterns, urban infrastructure may become more vulnerable to flooding. Flooding mitigation strategies must be developed such that the failure of infrastructure does not compromise people, activities, or other infrastructure. “Safe-to-fail” is an emerging paradigm that broadly describes adaptation scenarios that allow infrastructure to fail but control or minimize the consequences of the failure. Traditionally, infrastructure is designed as “fail-safe” where they provide robust protection when the risks are accurately predicted within a designed safety factor. However, the risks and uncertainties faced by urban infrastructure are becoming so great due to climate change that the “fail-safe” paradigm should be questioned. We propose a framework to assess potential flooding solutions based on multiple infrastructure resilience characteristics using a multi-criteria decision analysis (MCDA) analytic hierarchy process algorithm to prioritize “safe-to-fail” and “fail-safe” strategies depending on stakeholder preferences. Using urban flooding in Phoenix, Arizona, as a case study, we first estimate flooding intensity and evaluate roadway vulnerability using the Storm Water Management Model for a series of downpours that occurred on September 8, 2014. Results show the roadway types and locations that are vulnerable. Next, we identify a suite of adaptation strategies and characteristics of these strategies and attempt to more explicitly categorize flooding solutions as “safe-to-fail” and “fail-safe” with these characteristics. Lastly, we use MCDA to show how adaptation strategy rankings change when stakeholders have different preferences for particular adaptation characteristics. DA - 2017/10/26/ PY - 2017/10/26/ DO - 10.1007/s10584-017-2090-1 VL - 145 IS - 3-4 SP - 397-412 J2 - Climatic Change LA - en OP - SN - 0165-0009 1573-1480 UR - http://dx.doi.org/10.1007/s10584-017-2090-1 DB - Crossref ER - TY - JOUR TI - Reducing uncertainty in stochastic streamflow generation and reservoir sizing by combining observed, reconstructed and projected streamflow AU - Patskoski, Jason AU - Sankarasubramanian, A. T2 - Stochastic Environmental Research and Risk Assessment DA - 2017/9/21/ PY - 2017/9/21/ DO - 10.1007/s00477-017-1456-2 VL - 32 IS - 4 SP - 1065-1083 J2 - Stoch Environ Res Risk Assess LA - en OP - SN - 1436-3240 1436-3259 UR - http://dx.doi.org/10.1007/s00477-017-1456-2 DB - Crossref KW - Bayesian KW - Streamflow KW - Reservoir Sizing KW - Climate change projections KW - Paleoclimatology ER - TY - JOUR TI - Utilizing Probabilistic Downscaling Methods to Develop Streamflow Forecasts from Climate Forecasts AU - Mazrooei, Amirhossein AU - Sankarasubramanian, A. T2 - Journal of Hydrometeorology AB - Abstract Statistical information from ensembles of climate forecasts can be utilized in improving the streamflow predictions by using different downscaling methods. This study investigates the use of multinomial logistic regression (MLR) in downscaling large-scale ensemble climate forecasts into basin-scale probabilistic streamflow forecasts of categorical events over major river basins across the U.S. Sun Belt. The performance of MLR is then compared with the categorical forecasts estimated from the traditional approach, principal component regression (PCR). Results from both cross validation and split sampling reveal that in general, the probabilistic categorical forecasts from the MLR model have more accuracy and exhibit higher rank probability skill score (RPSS) compared to the PCR probabilistic forecasts. MLR forecasts are also more skillful than PCR forecasts during the winter season as well as for basins that exhibit high interannual variability in streamflows. The role of ensemble size of precipitation forecasts in developing MLR-based streamflow forecasts was also investigated. Because of its simplicity, MLR offers an alternate, reliable approach to developing categorical streamflow forecasts. DA - 2017/11// PY - 2017/11// DO - 10.1175/JHM-D-17-0021.1 VL - 18 IS - 11 SP - 2959-2972 J2 - J. Hydrometeor. LA - en OP - SN - 1525-755X 1525-7541 UR - http://dx.doi.org/10.1175/JHM-D-17-0021.1 DB - Crossref ER - TY - JOUR TI - Reducing Model Structural Uncertainty in Climate Model Projections—A Rank-Based Model Combination Approach AU - Bhowmik, R. Das AU - Sharma, A. AU - Sankarasubramanian, A. T2 - Journal of Climate AB - Future changes in monthly precipitation are typically evaluated by estimating the shift in the long-term mean/variability or based on the change in the marginal distribution. General circulation model (GCM) precipitation projections deviate across various models and emission scenarios and hence provide no consensus on the expected future change. The current study proposes a rank/percentile-based multimodel combination approach to account for the fact that alternate model projections do not share a common time indexing. The approach is evaluated using 10 GCM historical runs for the current period and is validated by comparing with two approaches: equal weighting and a non-percentile-based optimal weighting. The percentile-based optimal combination exhibits lower values of RMSE in estimating precipitation terciles. Future (2000–49) multimodel projections show that January and July precipitation exhibit an increase in simulated monthly extremes (25th and 75th percentiles) over many climate regions of the conterminous United States. DA - 2017/12// PY - 2017/12// DO - 10.1175/JCLI-D-17-0225.1 VL - 30 IS - 24 SP - 10139-10154 J2 - J. Climate LA - en OP - SN - 0894-8755 1520-0442 UR - http://dx.doi.org/10.1175/JCLI-D-17-0225.1 DB - Crossref ER - TY - JOUR TI - Patterns and drivers of fish extirpations in rivers of the American Southwest and Southeast AU - Kominoski, John S. AU - Ruhí, Albert AU - Hagler, Megan M. AU - Petersen, Kelly AU - Sabo, John L. AU - Sinha, Tushar AU - Sankarasubramanian, Arumugam AU - Olden, Julian D. T2 - Global Change Biology AB - Effective conservation of freshwater biodiversity requires spatially explicit investigations of how dams and hydroclimatic alterations among climate regions may interact to drive species to extinction. We investigated how dams and hydroclimatic alterations interact with species ecological and life history traits to influence past extirpation probabilities of native freshwater fishes in the Upper and Lower Colorado River (CR), Alabama-Coosa-Tallapoosa (ACT), and Apalachicola-Chattahoochee-Flint (ACF) basins. Using long-term discharge data for continuously gaged streams and rivers, we quantified streamflow anomalies (i.e., departure "expected" streamflow) at the sub-basin scale over the past half-century. Next, we related extirpation probabilities of native fishes in both regions to streamflow anomalies, river basin characteristics, species traits, and non-native species richness using binomial logistic regression. Sub-basin extirpations in the Southwest (n = 95 Upper CR, n = 130 Lower CR) were highest in lowland mainstem rivers impacted by large dams and in desert springs. Dampened flow seasonality, increased longevity (i.e., delayed reproduction), and decreased fish egg sizes (i.e., lower parental care) were related to elevated fish extirpation probability in the Southwest. Sub-basin extirpations in the Southeast (ACT n = 46, ACF n = 22) were most prevalent in upland rivers, with flow dependency, greater age and length at maturity, isolation by dams, and greater distance upstream. Our results confirm that dams are an overriding driver of native fish species losses, irrespective of basin-wide differences in native or non-native species richness. Dams and hydrologic alterations interact with species traits to influence community disassembly, and very high extirpation risks in the Southeast are due to interactions between high dam density and species restricted ranges. Given global surges in dam building and retrofitting, increased extirpation risks should be expected unless management strategies that balance flow regulation with ecological outcomes are widely implemented. DA - 2017/11/15/ PY - 2017/11/15/ DO - 10.1111/gcb.13940 VL - 24 IS - 3 SP - 1175-1185 J2 - Glob Change Biol LA - en OP - SN - 1354-1013 1365-2486 UR - http://dx.doi.org/10.1111/gcb.13940 DB - Crossref KW - biodiversity loss KW - dams KW - flow regime KW - global change KW - imperiled species ER - TY - JOUR TI - Performance and damage evolution of plain and fibre-reinforced segmental concrete pipelines subjected to transverse permanent ground displacement AU - Pour-Ghaz, Mohammad AU - Wilson, Jacob AU - Spragg, Robert AU - Nadukuru, Srinivasa (Sid) S. AU - Kim, Junhee AU - O’Connor, Sean M. AU - Byrne, Edward M. AU - Sigurdardottir, Dorotea H. AU - Yao, Yao AU - Michalowski, Radoslaw L. AU - Lynch, Jerome P. AU - Green, Russell A. AU - Bradshaw, Aaron S. AU - Glisic, Branko AU - Weiss, Jason T2 - Structure and Infrastructure Engineering AB - This paper presents the results of three full-scale experiments performed on segmental concrete pipelines subjected to permanent ground displacement. The first pipeline was made of reinforced concrete pipes and the second pipeline was made of steel fibre-reinforced concrete pipes. The third pipeline was made of a combination of fibre-reinforced and reinforced concrete pipes. An array of sensing techniques was used to assess the damage evolution in pipelines and their overall performance. Three stages of damage were observed. In the first stage, damage was concentrated in the joints near the fault line. In the second stage, the damage occurred in all joints along the pipeline. While in the first two stages damage was mainly concentrated at the bell and spigot joints of the pipe segments, the third stage of damage was characterised by severe damage and rupture of the body of pipe segments located in the immediate vicinity of the fault line. The modes of failure for the plain and fibre-reinforced concrete pipelines were similar in the first and second stages of damage. However, in the pipeline constructed using both plain and fibre-reinforced concrete pipe segments, the damage was concentrated in the standard reinforced concrete pipe segments. DA - 2017/7/12/ PY - 2017/7/12/ DO - 10.1080/15732479.2017.1349809 VL - 14 IS - 2 SP - 232-246 J2 - Structure and Infrastructure Engineering LA - en OP - SN - 1573-2479 1744-8980 UR - http://dx.doi.org/10.1080/15732479.2017.1349809 DB - Crossref KW - Concrete reinforced KW - damage assessment KW - earthquake engineering KW - pipes & pipelines KW - sensors KW - soil-structure interaction KW - permanent ground displacement ER - TY - JOUR TI - Social network analysis for construction crews AU - Abbsaian-Hosseini, S. Alireza AU - Liu, Min AU - Hsiang, Simon M. T2 - International Journal of Construction Management AB - Construction crews usually have to share the limited working space with each other during construction to perform their tasks, which increases the chance of interference/conflict and productivity lost. Social network analysis (SNA) has been known as a methodology to determine the conditions of social structures by investigating the interdependencies among a set of actors. The impact of jobsite social network on the performance of the crews has not been well documented in previous research. This research proposes an analytical approach by combining SNA and work plan variation analysis to (1) quantify the influence construction crews receive from jobsite social network, and (2) explore the impact of jobsite social network on the crews’ performance particularly on their work plan variation through a case study. The results indicated that there is a positive monotonic association between each of the centrality indices (representing network influence on each crew) and each of the work plan variability indices (representing crew's performance). The more influences a crew receives form the network, the more work plan variation it will have. A better understanding of the existing jobsite interdependencies will help project managers to control it through better planning and leadership, consequently increasing jobsite productivity. DA - 2017/11/3/ PY - 2017/11/3/ DO - 10.1080/15623599.2017.1389642 VL - 19 IS - 2 SP - 113-127 J2 - International Journal of Construction Management LA - en OP - SN - 1562-3599 2331-2327 UR - http://dx.doi.org/10.1080/15623599.2017.1389642 DB - Crossref KW - Social network analysis KW - construction crews KW - centrality KW - variations KW - interdependency KW - work plan KW - construction management KW - productivity ER - TY - JOUR TI - Improving rural electricity system planning: An agent-based model for stakeholder engagement and decision making AU - Alfaro, Jose F. AU - Miller, Shelie AU - Johnson, Jeremiah X. AU - Riolo, Rick R. T2 - Energy Policy AB - Energy planners in regions with low rates of electrification face complex and high-risk challenges in selecting appropriate generating technologies and grid centralization. To better inform such processes, we present an Agent-Based Model (ABM) that facilitates engagement with stakeholders. This approach evaluates long-term plans using the cost of delivered electricity, resource mix, jobs and economic stimulus created within communities, and decentralized generation mix of the system, with results provided in a spatially-resolved format. This approach complements existing electricity planning methods (e.g., Integrated Resource Planning) by offering novel evaluation criteria based on typical stakeholder preferences. We demonstrate the utility of this approach with a case study based on a “blank-slate” scenario, which begins without generation or transmission infrastructure, for the long-term rural renewable energy plans of Liberia, West Africa. We consider five electrification strategies: prioritizing larger populations, deploying large resources, creating jobs, providing economic stimulus, and step-wise cost minimization. Through the case study we demonstrate how this approach can be used to engage stakeholders, supplement more established energy planning tools, and illustrate the effects of stakeholder decisions and preferences on the performance of the system. DA - 2017/2// PY - 2017/2// DO - 10.1016/j.enpol.2016.10.020 VL - 101 SP - 317-331 J2 - Energy Policy LA - en OP - SN - 0301-4215 UR - http://dx.doi.org/10.1016/j.enpol.2016.10.020 DB - Crossref KW - Developing countries KW - Agent-based modeling KW - Policy planning KW - Rural electrification ER - TY - JOUR TI - Diversifying wind power in real power systems AU - Novacheck, Joshua AU - Johnson, Jeremiah X. T2 - Renewable Energy AB - One method to reduce wind variability is to diversify the wind power resource by interconnecting wind resources across a larger geography. This study uses a modified version of mean-variance portfolio optimization (MVP) to assess the potential for diverse wind to reduce the variability of wind. A one year unit commitment and economic dispatch model of the U.S. Midwest is used to understand the value of the reduced variability. The model assesses four different wind portfolios, ranging in diversity, of two wind power penetrations (10% of total system load and 20%). Employing MVP, the variance in the ramp rates decrease by 50% with a 4% increase in capacity in the 20% wind penetration and a 2% increase in the 10% penetration. With a 20% wind penetration, decreasing the ramp rate variance can reduce curtailment from 5% to 0.1%. In the absence of significant curtailment, decreasing the ramp rate variance reduces the proportion of conventional generation required for ramping. However, the impact on total production cost and emissions from conventional generation is complicated by complexities of the power system, including transmission constraints and the time of day of ramping. DA - 2017/6// PY - 2017/6// DO - 10.1016/j.renene.2016.12.100 VL - 106 SP - 177-185 J2 - Renewable Energy LA - en OP - SN - 0960-1481 UR - http://dx.doi.org/10.1016/j.renene.2016.12.100 DB - Crossref KW - Wind diversity KW - Unit commitment and economic dispatch KW - Wind power variability KW - Optimization ER - TY - JOUR TI - Parameters driving environmental performance of energy storage systems across grid applications AU - Arbabzadeh, Maryam AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. T2 - Journal of Energy Storage AB - Large-scale energy storage may effectively meet the needs of several grid applications. However, understanding the environmental impact of energy storage for these grid applications is challenging due to diversity in loads, grid mixes, and energy storage systems. Comprehensive sustainability assessments are necessary to yield the best environmental outcomes for grid-scale energy storage systems. To achieve this, we first developed fundamental principles for green energy storage, addressing key issues such as material sustainability, round-trip efficiency, service life, and degradation. In the current study, we couple the principles with a sustainability assessment model to investigate the impact of design and operational parameters on environmental outcomes of utilizing energy storage for grid applications. This model takes into account the service that the energy storage would provide (e.g., bulk energy time-shifting) as well as the energy storage parameters and grid application parameters that influence environmental outcomes. Parameters examined include energy storage round-trip efficiency, degradation, service life, upstream production burden, and heat rates of charging and displaced generation technologies. Environmental sustainability performance is evaluated using a universal set of equations that incorporates all the mentioned parameters. The relationships between these parameters are investigated to determine their influence on environmental performance of energy storage for three grid applications: energy time-shifting, frequency regulation, and power reliability. This model guides the design and operation of new and existing technologies, targeting audiences from energy storage designers to energy storage operators and power utilities. DA - 2017/8// PY - 2017/8// DO - 10.1016/j.est.2017.03.011 VL - 12 SP - 11-28 J2 - Journal of Energy Storage LA - en OP - SN - 2352-152X UR - http://dx.doi.org/10.1016/j.est.2017.03.011 DB - Crossref KW - Energy storage KW - Environmental outcomes KW - Life cycle emissions KW - Sustainability KW - Design and operational parameters ER - TY - JOUR TI - Location or insolation: the importance of siting in emissions mitigation from solar photovoltaics AU - Johnson, Jeremiah X. T2 - Wiley Interdisciplinary Reviews: Energy and Environment AB - Achieving environmental benefits is often a primary motivation for integrating renewable energy into the grid. The magnitude of generation from a solar power project is influenced by the solar resource quality, but locations with high insolation do not necessarily yield the greatest emission reduction benefits. This study simulates the power system response to 10 identical solar projects in different regions across the United States, selected to represent a wide range of solar resource quality and power grid configurations. The power grid mix is often a key determinant in offsetting CO 2 , SO 2 , and NO x emissions, illustrating how lower‐quality solar resources can be more effective than sunnier sites at emissions mitigation when one considers characteristics of the power grid. The analysis shows a strong relationship between emissions mitigation and the share of offset generation that is coal‐fired. The strongest correlation is shown for CO 2 ; the presence or absence of emissions control equipment and the sulfur content of the coal complicates the relationship of SO 2 and NO x . The emissions intensity of offset generation is insensitive to whether the solar project is fixed tilt or single‐axis tracking. When seeking to mitigate power sector emissions, the impacts of solar design considerations on the temporal profile of generation are less important than the overall amount of generation and the location of interconnection. Public policies that target only the magnitude of generation from renewables (e.g., many Renewable Portfolio Standards) or the installed cost (e.g., the Investment Tax Credit) will likely lead to suboptimal emissions mitigation. WIREs Energy Environ 2017, 6:e249. doi: 10.1002/wene.249 This article is categorized under: Photovoltaics > Climate and Environment Energy and Development > Systems and Infrastructure DA - 2017/4/24/ PY - 2017/4/24/ DO - 10.1002/wene.249 VL - 6 IS - 5 SP - e249 J2 - WIREs Energy Environ LA - en OP - SN - 2041-8396 UR - http://dx.doi.org/10.1002/wene.249 DB - Crossref ER - TY - JOUR TI - Explaining inefficiencies in commercial buildings providing power system ancillary services AU - Lin, Yashen AU - Mathieu, Johanna L. AU - Johnson, Jeremiah X. AU - Hiskens, Ian A. AU - Backhaus, Scott T2 - Energy and Buildings AB - Ancillary services are required to balance supply and demand in electric power systems. Demand response may provide attractive options for these services, through means such as varying the power consumption of commercial building HVAC systems. However, experimental results from a 30,000 m2 office building suggest that when a building provides ancillary services it consumes more energy than when it is operated normally. This translates to additional costs and environmental impacts. This paper investigates potential causes for building inefficiency associated with ancillary services provision. We develop a physics-based simulation model that captures heat exchange processes and fan and air duct dynamics. During an ancillary service event, we vary the fan power consumption, and then compute the difference between the baseline and actual energy consumption to determine the efficiency of the actions. We explore the impact of building parameters, control design, and baseline model accuracy on the efficiency. In simulation, we find that shorter duration power changes and less aggressive controllers result in less change in energy consumption. We also find that baseline error has outsized effects on the efficiency calculations. These results offer new understanding of the mechanisms underlying inefficiency and point to opportunities to reduce associated costs and environmental burdens. DA - 2017/10// PY - 2017/10// DO - 10.1016/j.enbuild.2017.07.042 VL - 152 SP - 216-226 J2 - Energy and Buildings LA - en OP - SN - 0378-7788 UR - http://dx.doi.org/10.1016/j.enbuild.2017.07.042 DB - Crossref KW - Ancillary services KW - Commercial buildings KW - Energy efficiency KW - HVAC ER - TY - JOUR TI - Agent-based modelling approach to evaluate the effect of collaboration among scientists in scientific workflows AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman T2 - Journal of Simulation AB - Automation in science is increasingly marked by the use of workflow systems (eg, Matlab) to facilitate the scientific discovery. The sharing of workflows through publication mechanisms supports the reproducibility and extensibility of computational experiments. However, the subsequent scientific discovery from a workflow relates to the level of collaboration among scientists. An agent-based model (ABM) is developed by coupling a scientific workflow with a model of scientist agents. The scientist agents are able to collaborate using a simplified small-world network. After a query is submitted to scientist agents, each scientist agent is able to extract data from data-sets, which are widely available online, using automated workflows to prepare a scientific report for a query. After data are collected from a workflow, data can be shared among scientists using one of the four collaboration scenarios, which simulate alternative level of data availability. Each scientist uses the data, which is collected from the database or through a shared environment, to deduce a scientific discovery. The ABM is demonstrated and evaluated for application within ecological science. Scientist agents collaborate and use the workflow tool, Kepler, to develop a linear regression model that captures the relationship between zooplankton populations and codfish population in the Norwegian Sea. DA - 2017/10/26/ PY - 2017/10/26/ DO - 10.1080/17477778.2017.1387333 VL - 13 IS - 1 SP - 1-13 J2 - Journal of Simulation LA - en OP - SN - 1747-7778 1747-7786 UR - http://dx.doi.org/10.1080/17477778.2017.1387333 DB - Crossref KW - Scientific workflow KW - collaboration KW - agent-based modelling ER - TY - JOUR TI - The Impact of Demographic Factors, Beliefs, and Social Influences on Residential Water Consumption and Implications for Non-Price Policies in Urban India AU - Ramsey, Elizabeth AU - Berglund, Emily AU - Goyal, Rohit T2 - Water AB - In rapidly growing urban areas in India and the developing world, water demands typically exceed supply. While local governments may implement management programs to reduce demand for freshwater, water savings are dependent on the conservation behaviors of individuals. A household survey is presented here to examine residential water end uses and conservation behaviors in Jaipur, India. The survey explores end uses, engagement in conservation behaviors, and the influence of demographic factors, water sources, beliefs about water, and social pressures on these behaviors are tested. The survey was conducted at 248 households, including 29 households in the slums. Our study finds that while the majority of participants recognize the importance of water conservation, they do not necessarily conserve water themselves. Households report engaging most frequently in water-conservation behaviors that require little effort or financial investment. Multivariate analysis of variance (MANOVA) results and subsequent pairwise comparisons indicate higher incomes, longer water-supply durations, and the belief that droughts are preventable are positively correlated with overall amenability to adoption of water-conservation behaviors and technology. Binomial logistic regression analysis indicates that being in the age group 26–35, having higher income, and giving a neutral response about the responsibility of the government to provide relief during a drought were all predictors of the installation of dual-flush (DF) toilets. Education levels and water awareness were found to have no correlation with conservation behaviors or amenability to conservation technology adoption. Results are applied to examine their possible implications from a demand-management perspective and provide suggestions for further research and policy decisions. DA - 2017/11/2/ PY - 2017/11/2/ DO - 10.3390/w9110844 VL - 9 IS - 11 SP - 844 J2 - Water LA - en OP - SN - 2073-4441 UR - http://dx.doi.org/10.3390/w9110844 DB - Crossref KW - residential water consumption KW - water conservation KW - water scarcity KW - water demand management KW - non-price policies KW - socio-hydrology KW - household survey KW - social norms KW - South Asia KW - India ER - TY - JOUR TI - Electricity generation using continuously recirculated flow electrodes in reverse electrodialysis AU - Liu, Fei AU - Coronell, Orlando AU - Call, Douglas F. T2 - Journal of Power Sources AB - Capacitive flow electrode systems that generate electricity from salinity gradients are limited by low power densities, inefficient electrical current collection, and complex system operation. We show here the proof-of-concept that a single reverse electrodialysis cell using continuously recirculated activated carbon flow electrodes can generate uninterrupted electricity from an artificial sea/river water gradient. Power densities reached 61 ± 5.7 mW m−2 (normalized to total membrane surface area) and current densities 2.4 ± 0.13 A m−2 when a 10% by weight carbon loading was used with graphite plate current collectors. Using high-surface area graphite brush current collectors, maximum power densities increased more than 320% to 260 ± 8.7 mW m−2 and maximum current densities more than 400% to 14 ± 0.59 A m−2. The performance improvements were attributed to a more than 80% decrease in electrode resistances when brushes were used instead of plates. A control static capacitive electrode system obtained slightly higher average power densities (290 ± 8.7 mW m−2), but could not produce it continuously, highlighting the operational advantage of the recirculated flow electrode design. DA - 2017/7// PY - 2017/7// DO - 10.1016/j.jpowsour.2017.04.061 VL - 355 SP - 206-210 J2 - Journal of Power Sources LA - en OP - SN - 0378-7753 UR - http://dx.doi.org/10.1016/j.jpowsour.2017.04.061 DB - Crossref KW - Flow electrode KW - Revere electrodialysis KW - Salinity gradient energy KW - Graphite brush current collector ER - TY - JOUR TI - Investigation and modelling of asphalt pavement performance in cold regions AU - Zeiada, Waleed AU - Hamad, Khaled AU - Omar, Maher AU - Underwood, B. Shane AU - Khalil, Mohamad Ali AU - Karzad, Abdul Saboor T2 - International Journal of Pavement Engineering AB - The performance of asphalt pavement is highly affected by climate factors, such as temperature and precipitation. Different temperature and moisture conditions change the paving material properties, which consequently influence pavement performance. Considerable research has been conducted to study the effect of climate factors on pavement performance; however, there are no focused studies that have investigated the performance of asphalt pavements in cold regions. In this research, the effect of different design factors on asphalt pavement performance in cold regions is investigated utilising data extracted from the Long-Term Pavement Performance database. Only control sections with no historical maintenance or rehabilitation records were considered. The International Roughness Index (IRI) was adopted as the pavement performance measure. The IRI value is expected to increase gradually over time due to pavement deterioration. Initial screening of the data showed that most of the pavement sections experienced remarkable IRI increase followed by an unexpected decrease. An in-depth investigation revealed that frost heave was the main reason of this unexpected IRI trend as it was correlated in most of the cases to sudden monthly freezing index increases, especially for sections with no subsurface drainage and less layers thicknesses. An Artificial Neural Network with a Forward Sequential Feature Selection algorithm and regression analysis were employed to model pavement performance in cold regions and determine the most significant design factors prevailing in cold climate conditions. Moreover, a sensitivity analysis was performed to investigate the interrelation between the considered features and the IRI. As a result, several climate-related factors were found to have a significant impact on the performance of asphalt pavements in cold regions such as average temperature, freezing index, freeze/thaw, wind velocity and relative humidity. DA - 2017/9/11/ PY - 2017/9/11/ DO - 10.1080/10298436.2017.1373391 VL - 20 IS - 8 SP - 986-997 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2017.1373391 DB - Crossref KW - Pavement performance KW - frost heave KW - cold regions KW - LTPP KW - artificial neural network KW - sequential feature selection ER - TY - JOUR TI - Application of a Life Cycle Model for European Union Policy-Driven Waste Management Decision Making in Emerging Economies AU - Stanisavljevic, Nemanja AU - Levis, James W. AU - Barlaz, Morton A. T2 - Journal of Industrial Ecology AB - Summary Solid waste life cycle modeling has predominantly focused on developed countries, but there are significant opportunities to assist developing and transition economies to minimize the environmental impact of solid waste management (SWM). Serbia is representative of a transition country and most (92%) of its waste is landfilled. As a Candidate European Union (EU) country, Serbia is expected to implement SWM strategies that meet EU directives. The Solid Waste Life‐Cycle Optimization Framework (SWOLF) was used to evaluate scenarios that meet EU goals by 2030. Scenarios included combinations of landfills, anaerobic digestion, composting, material recovery facilities (MRFs), waste‐to‐energy (WTE) combustion, and the use of refuse‐derived fuel in cement kilns. Each scenario was evaluated with and without separate collection of recyclables. Modeled impacts included cost, climate change, cumulative fossil energy demand, acidification, eutrophication, photochemical oxidation, total eco‐toxicity, and total human toxicity. Trade‐offs among the scenarios were evaluated because no scenario performed best in every category. In general, SWM strategies that incorporated processes that recover energy and recyclable materials performed well across categories, whereas scenarios that did not include energy recovery performed poorly. Emissions offsets attributable to energy recovery and reduced energy requirements associated with remanufacturing of recovered recyclables had the strongest influence on the results. The scenarios rankings were robust under parametric sensitivity analysis, except when the marginal electricity fuel source changed from coal to natural gas. Model results showed that the use of existing infrastructure, energy recovery, and efficient recovery of recyclables from mixed waste can reduce environmental emissions at relatively low cost. DA - 2017/3/22/ PY - 2017/3/22/ DO - 10.1111/jiec.12564 VL - 22 IS - 2 SP - 341-355 J2 - Journal of Industrial Ecology LA - en OP - SN - 1088-1980 UR - http://dx.doi.org/10.1111/jiec.12564 DB - Crossref ER - TY - JOUR TI - Emission factors of health- and climate-relevant pollutants measured in home during a carbon-finance-approved cookstove intervention in rural India AU - Grieshop, Andrew P. AU - Jain, Grishma AU - Sethuraman, Karthik AU - Marshall, Julian D. T2 - GeoHealth AB - Abstract We present results of an emission characterization effort, completed as part of a larger intervention trial, of a carbon‐finance‐approved program replacing traditional cookstoves with “rocket”‐style natural draft stoves. The 100 emission tests were conducted across 31 households in control and intervention groups, with repeated tests in most households during preintervention and postintervention periods. While mean fine particulate matter (PM 2.5 ) emission factor for intervention stoves was significantly lower than for traditional stoves in baseline measurements, they were only marginally lower than traditional stoves during follow‐up. Intervention stove PM 2.5 emissions had a larger contribution from light‐absorbing (elemental) carbon than traditional stoves. Repeated measurements in control households provide evidence for strong seasonality, likely due to differences in fuel moisture/types, in traditional stove emissions, with important implications for study design. Seasonality observed in control household emission factors (baseline > follow‐up) was in the opposite direction as that observed in indoor PM 2.5 concentrations (baseline < follow‐up), highlighting that seasonally varying conditions (e.g., ventilation rates) may modify the link between emissions and exposures. Emission factor differences in paired (pre/post) tests from the same households were similar to differences in the medians of entire groups, suggesting variability is dominated by test‐to‐test variation. Emission reductions from intervention stoves were significantly smaller than laboratory performance would suggest or that are required to strongly reduce exposures. Field emissions assessment like that presented here should be prioritized early in technology assessment and development to provide rigorous estimates of the benefits reasonably expected from interventions with the potential for substantial benefits to human health and the environment. DA - 2017/7// PY - 2017/7// DO - 10.1002/2017gh000066 VL - 1 IS - 5 SP - 222-236 J2 - GeoHealth LA - en OP - SN - 2471-1403 UR - http://dx.doi.org/10.1002/2017gh000066 DB - Crossref KW - environmental health KW - indoor air quality KW - intervention trial KW - CDM KW - household energy KW - household air pollution ER - TY - JOUR TI - Vs-κ0 Correction Factors for Input Ground Motions used in Seismic Site Response Analyses AU - Cabas, Ashly AU - Rodriguez-Marek, Adrian T2 - Earthquake Spectra AB - Input motions used in seismic site response analyses are commonly selected based on similarities between the shear wave velocity (V s ) at the recording station, and the reference depth at the site of interest (among other aspects such as the intensity of the expected ground motion). This traditional approach disregards the influence of the attenuation in the shallow crust on site response. Given that this attenuation (damping) can be characterized by the distance-independent high-frequency attenuation parameter 0 , a V s - 0 correction framework for input motions is proposed to render them compatible with the assumed properties of the reference depth at the site. The proposed correction factors were applied to a subset of recordings from the KiK-net database, and compared to traditional deconvolution. Results indicate that V s - 0 corrected motions outperform deconvolved motions in the characterization of the spectral energy in the high-frequency range. However, motions recorded at sites with soft deposits are not good candidates for the V s - 0 correction approach. V s - 0 corrections also affect amplification functions which are important in the assessment of site-specific seismic hazards. DA - 2017/5/24/ PY - 2017/5/24/ DO - 10.1193/122315EQS188M J2 - Earthquake Spectra LA - en OP - SN - 8755-2930 UR - http://dx.doi.org/10.1193/122315EQS188M DB - Crossref ER - TY - CONF TI - Unintended consequences of a local limits revision: One utility's experience with fats, oils, and grease AU - Sadler, M. AU - Wischer, B. AU - Gordon, J. AU - Wilkerson, C. AU - Tabor, C. AU - Fredericks, D. AU - Ducoste, J. C2 - 2017/// C3 - Water Environment Federation Technical Exhibition and Conference 2017, WEFTEC 2017 DA - 2017/// VL - 8 SP - 5522-5534 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85052083486&partnerID=MN8TOARS ER - TY - JOUR TI - Supplementary material to "Maximizing Ozone Signals Among Chemical, Meteorological, and Climatological Variability" AU - Brown-Steiner, Benjamin AU - Selin, Noelle E. AU - Prinn, Ronald G. AU - Monier, Erwan AU - Tilmes, Simone AU - Emmons, Louisa AU - Garcia-Menendez, Fernando DA - 2017/11/28/ PY - 2017/11/28/ DO - 10.5194/acp-2017-954-supplement VL - 11 UR - https://doi.org/10.5194/acp-2017-954-supplement ER - TY - JOUR TI - On the relationships between commuting mode choice and public health AU - Tajalli, Mehrdad AU - Hajbabaie, Ali T2 - Journal of Transport & Health AB - This paper studies the associations that may exist between commuting mode choice and public health. For this purpose, we used Community Health Survey data collected in New York City in 2010. Obesity, blood pressure, and diabetes are used as indicators of respondents’ physical health, and Non-Specific Psychological Distress as an indicator of respondents’ mental health. After rigorous statistical analyses, a binary probit model was fitted for each physical and mental health indicator to quantify the associations between different commuting modes and physical/mental health. Results show that walking, as expected, is associated with a lower probability of obesity, hypertension, diabetes, and mental disorders (all statistically significant) when compared to using private transportation. Using subway is related to a lower probability of obesity and diabetes while using the city bus was linked with a higher probability of obesity (all statistically significant) compared to using personal vehicles. Finally, in comparison with using personal vehicles, working at home is associated with a higher probability of having mental disorders (statistically significant). DA - 2017/// PY - 2017/// DO - 10.1016/j.jth.2016.12.007 VL - 4 SP - 267-277 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85008457031&partnerID=MN8TOARS KW - Commuting mode choice KW - Public health KW - Mental health KW - Homeworking KW - Choice model KW - Binary probit ER - TY - JOUR TI - Estimation of saturation headway in work zones on urban streets AU - Hajbabaie, Ali AU - Kim, SangKey AU - Schroeder, Bastian J AU - Aghdashi, Seyedbehzad AU - Rouphail, Nagui M AU - Tabrizi, Kambiz T2 - Transportation research record AB - Work zones and lane closures on urban arterials can cause significant disruptions to the traveling public, and methods are increasingly needed to estimate the reductions to saturation flow rates that result from work zones at signalized intersections. A set of statistical models that estimate saturation headways as a function of the presence and configuration of the work zone on signalized arterial streets is presented. More than 10,000 individual vehicular headway observations were collected from video observations in and after work zones at six study sites in North Carolina. Conventional multiple-regression and path-based-regression models (structural equation model) were used to develop the saturation headway models. Three models are provided at different aggregation levels of the collected data with identical work zone configurations. The models developed at cycle-length, 15-min, and full aggregation produced adjusted R-squared values of .3259, .7209, and .895, respectively. The proposed model incorporates the effects of lane configuration, pavement condition, turning percentage from shared lanes, work intensity, and number of closed exclusive turning lanes. Based on path analysis, the structural equation model satisfies all the rule-of-thumb criteria for goodness-of-fit indices. The model uses Highway Capacity Manual default values for turning-vehicle headway effect as its intercept coefficient value. DA - 2017/// PY - 2017/// DO - 10.3141/2615-04 VL - 2615 IS - 1 SP - 26-34 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85015163407&partnerID=MN8TOARS ER - TY - JOUR TI - Distributed coordinated signal timing optimization in connected transportation networks AU - Al Islam, SMA Bin AU - Hajbabaie, Ali T2 - Transportation Research Part C: Emerging Technologies AB - Abstract This paper presents a Distributed-Coordinated methodology for signal timing optimization in connected urban street networks. The underlying assumption is that all vehicles and intersections are connected and intersections can share information with each other. The novelty of the work arises from reformulating the signal timing optimization problem from a central architecture, where all signal timing parameters are optimized in one mathematical program, to a decentralized approach, where a mathematical program controls the timing of only a single intersection. As a result of this distribution, the complexity of the problem is significantly reduced thus, the proposed approach is real-time and scalable. Furthermore, distributed mathematical programs continuously coordinate with each other to avoid finding locally optimal solutions and to move towards global optimality. We proposed a real-time and scalable solution technique to solve the problem and applied it to several case study networks under various demand patterns. The algorithm controlled queue length and maximized intersection throughput (between 1% and 5% increase compared to the actuated coordinated signals optimized in VISTRO) and reduced travel time (between 17% and 48% decrease compared to actuated coordinated signals) in all cases. DA - 2017/// PY - 2017/// DO - 10.1016/j.trc.2017.04.017 VL - 80 SP - 272-285 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85019418628&partnerID=MN8TOARS KW - Distributed-coordinated approach KW - Connected vehicles KW - Real-time and scalable KW - Signal timing optimization KW - Oversaturated flow conditions ER - TY - JOUR TI - A cell-based distributed-coordinated approach for network-level signal timing optimization AU - Mehrabipour, Mehrzad AU - Hajbabaie, Ali T2 - Computer-Aided Civil and Infrastructure Engineering AB - Abstract This article develops an efficient methodology to optimize the timing of signalized intersections in urban street networks. Our approach distributes a network‐level mixed‐integer linear program (MILP) to intersection level. This distribution significantly reduces the complexity of the MILP and makes it real‐time and scalable. We create coordination between MILPs to reduce the probability of finding locally optimal solutions. The formulation accounts for oversaturated conditions by using an appropriate objective function and explicit constraints on queue length. We develop a rolling‐horizon solution algorithm and apply it to several case‐study networks under various demand patterns. The objective function of the optimization program is to maximize intersection throughput. The comparison of the obtained solutions to an optimal solution found by a central optimization approach (whenever possible) shows a maximum of 1% gap on a number of performance measures over different conditions. DA - 2017/// PY - 2017/// DO - 10.1111/mice.12272 VL - 32 IS - 7 SP - 599-616 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85021053257&partnerID=MN8TOARS ER - TY - JOUR TI - Communication: A few words can make a big impact AU - Del Giudice, D. AU - Davies, A.B. T2 - Nature DA - 2017/// PY - 2017/// DO - 10.1038/541030e VL - 541 IS - 7635 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85016156962&partnerID=MN8TOARS ER - TY - JOUR TI - Another grand challenge: Diversity in environmental engineering AU - Blaney, L. AU - Perlinger, J. A. AU - Bartelt-Hunt, S. L. AU - Kandiah, R. AU - Ducoste, J. T2 - Environmental Engineering Science AB - As efforts to address grand challenges in engineering move forward, one important challenge has been conspicuously absent—improving diversity in science, technology, engineering, and math fields. Previous research has shown that diverse teams perform better in a range of output measures and are better equipped to objectively and creatively evaluate problems. Here, we make the case for including diversity as a critical component of our ability to enable transformative solutions to the grand challenges in environmental engineering. DA - 2017/// PY - 2017/// DO - 10.1089/ees.2017.0337 KW - environmental engineering KW - engineering education KW - demographics KW - gender KW - ethnicity KW - race ER - TY - RPRT TI - Additional analysis of the National Child Restraint Use Special Study AU - Raymond, P. AU - Searcy, S. AU - Findley, D. AU - Miller, S. AU - Redden, C. A3 - National Highway Traffic Safety Administration DA - 2017/10// PY - 2017/10// M1 - DOT HS 812 462 PB - National Highway Traffic Safety Administration SN - DOT HS 812 462 ER - TY - CONF TI - Ferry Terminal Wait Time Study AU - Findley, D.J. AU - Anderson, T. AU - Bert, S. AU - Nye, T. AU - Letchworth, W. T2 - The Transportation Research Board 96th Annual Meeting C2 - 2017/// C3 - Proceedings of the Transportation Research Board 96th Annual Meeting DA - 2017/// SP - 16-00024 PB - Transportation Research Board of the National Academies ER - TY - JOUR TI - Maximizing Ozone Signals Among Chemical, Meteorological, and Climatological Variability AU - Brown-Steiner, Benjamin AU - Selin, Noelle E. AU - Prinn, Ronald G. AU - Monier, Erwan AU - Tilmes, Simone AU - Emmons, Louisa AU - Garcia-Menendez, Fernando T2 - Atmospheric Chemistry and Physics Discussions AB - Abstract. The detection of meteorological, chemical, or other signals in modeled or observed air quality data – such as an estimate of a temporal trend in surface ozone data, or an estimate of the mean ozone of a particular region during a particular season – is a critical component of modern atmospheric chemistry. However, the magnitude of a surface air quality signal is generally small compared to the magnitude of the underlying chemical and meteorological variabilities that exist both in space and in time. This can present difficulties for both policy-makers and researchers as they attempt to identify the influence or signal of climate trends (e.g. any pauses in warming trends), the impact of enacted emission reductions policies (e.g. United States NOx State Implementation Plans), or an estimate of the mean state of highly variable data (e.g. summertime ozone over the Northeastern United States). Here we examine the scale-dependence of the variability of simulated and observed surface ozone data within the United States and the likelihood that a particular choice of temporal or spatial averaging scales produce a misleading estimate of a particular ozone signal. Our main objective is to develop strategies that reduce the likelihood of overconfidence in simulated ozone estimates. We find that while increasing the extent of both temporal and spatial averaging can enhance signal detection capabilities by reducing the noise from variability, a strategic combination of particular temporal and spatial averaging scales can maximize signal detection capabilities over much of the Continental US. We recommend temporal averaging of at least 10–15 years combined with regional spatial averaging over several hundred kilometer spatial scales. These results are consistent between simulated and observed data, and within a single model with different sets of parameters. The strategies selected in this study are not limited to surface ozone data, and could potentially maximize signal detection capabilities within a broad array of climate and chemical observations or model output. DA - 2017/11/28/ PY - 2017/11/28/ DO - 10.5194/acp-2017-954 VL - 11 SP - 1-38 UR - https://doi.org/10.5194/acp-2017-954 ER - TY - CONF TI - Key factors affecting inter-county variability in moves county-level energy inventory AU - Khan, T. AU - Frey, H.C. C2 - 2017/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2017/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039169682&partnerID=MN8TOARS ER - TY - CONF TI - Development of simplified models of CNG, diesel, and hybrid transit bus energy use AU - Wei, T. AU - Khan, T. AU - Frey, H.C. C2 - 2017/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2017/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039153359&partnerID=MN8TOARS ER - TY - JOUR TI - Crowdsourcing BIM-guided collection of construction material library from site photologs AU - Han, Kevin AU - Golparvar-Fard, Mani T2 - Visualization in Engineering AB - Abstract Background With advances in technologies that enabled massive visual data collection and BIM, the AEC industry now has an unprecedented amount of visual data (e.g., images and videos) and BIMs. One of the past efforts to leverage these data includes the Construction Material Library (CML) that was created for inferring construction progress by automatically detecting construction materials. CML has a limited number of construction material classes because it is merely impossible for an individual or a group of researchers to collect all possible variations of construction materials. Methods This paper proposes a web-based platform that streamlines the data collection process for creating annotated material patches guided by BIM overlays. Result Construction site images with BIM overlays are automatically generated after image-based 3D reconstruction. These images are deployed on a web-based platform for annotations. Conclusion The proposed crowdsourcing method using this platform has potential to scale up data collection for expanding the existing CML. A case study was conducted to validate the feasibility of the proposed method and to improve the web interface before deployment to a public cloud environment. DA - 2017/12// PY - 2017/12// DO - 10.1186/s40327-017-0052-3 VL - 5 IS - 1 UR - https://doi.org/10.1186/s40327-017-0052-3 ER - TY - CONF TI - Verifying Concurrency in an Adaptive Ocean Circulation Model AU - Altuntas, Alper AU - Baugh, John AB - We present a model checking approach for verifying the correctness of concurrency in numerical models. The forms of concurrency we address are from (1) coupled modeling where distinct components, e.g., ocean, wave, and atmospheric, exchange interface conditions during runtime, and (2) multi-instance modeling where local variations of the same numerical model are executed concurrently to minimize common (and therefore redundant) computations. We present general guidelines for representing these forms of concurrency in an abstract verification model and then apply them to an adaptive ocean circulation model that determines the geographic extent and severity of coastal floods. The ocean model employs multi-instance concurrency: a collection of engineering design and failure scenarios are concurrently simulated using patches, regions of a grid that grow and shrink based on the hydrodynamic changes induced by each scenario. We show how concurrency inherent in the simulation model can be represented in a verification model to ensure correctness and to automatically generate safe synchronization arrangements. C2 - 2017/// C3 - Proceedings of the First International Workshop on Software Correctness for HPC Applications - Correctness'17 DA - 2017/// DO - 10.1145/3145344.3145346 PB - ACM Press ER - TY - JOUR TI - Editorial AU - Daniel, Jo Sias AU - Kim, Y. Richard AU - Roque, Reynaldo T2 - ROAD MATERIALS AND PAVEMENT DESIGN DA - 2017/// PY - 2017/// DO - 10.1080/14680629.2017.1389095 VL - 18 SP - 1-1 SN - 2164-7402 ER - TY - CONF TI - Creep-fatigue damage evaluation of modified grade 91 headers using damage coupled unified viscoplastic model AU - Islam, N. AU - Dewees, D. J. AU - Cooch, M. AU - Hassan, T. AB - A case study for life prediction of Grade 91 heat recovery steam generator (HRSG) superheater outlet header of typical combined cycle power plants (CCPP) is presented in this paper. The effect of high cycling and fast startup along with elevated design temperature and pressure on the creep life is studied. A consistent material model based on MPC Omega is used to evaluate the creep damage of HRSG header components. In addition, a robust unified constitutive model (UCM) based on continuum damage mechanics (CDM) (see [1]) is used for creep-fatigue damage evaluation of the header components. The performance of the UCM is compared against creep and damage focused models in predicting the life of HRSG header components subjected to steady operation condition with low cycle fatigue scenario. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference, 2017, Vol 3B DA - 2017/// DO - 10.1115/pvp2017-65851 ER - TY - CONF TI - Unified viscoplastic model coupled with damage for evaluation of creep-fatigue of grade 91 steel AU - Islam, N. AU - Dewees, D. J. AU - Hassan, T. AB - A continuum damage mechanics (CDM) coupled unified viscoplasticity model has been developed to predict the creep-fatigue life of modified Grade 91 steel. A tertiary creep model termed MPC-Omega codified in Part 10 of API (and also implemented in the ASME BP&V Code for Grade 22V and more recently Grade 91 Steel) is also employed for creep damage evaluation. As MPC-Omega has a direct relationship with Larson-Miller parameter (LMP) coefficients, creep damage coefficients in the unified constitutive model (UCM) are tied with MPC-Omega coefficients in order to utilize WRC and API 579-1 Grade 91 creep rupture database. The model is validated against long-term creep, LCF, creep-fatigue and TMF experimental responses at T = 20–600°C. C2 - 2017/// C3 - Proceedings of the ASME pressure vessels and piping conference, 2017, vol 6a DA - 2017/// DO - 10.1115/pvp2017-65849 ER - TY - CONF TI - Perspective-Based Image-to-BIM Alignment for Automated Visual Data Collection and Construction Performance Monitoring AU - Boroujeni, K. A. AU - Han, K. AB - In efforts to automate construction performance monitoring, past studies have worked on vision-based registration of image to BIM and 3D point clouds to BIM. The continuous development of simultaneous localization and mapping (SLAM) enabled real-time estimation of locations and orientations of a camera while incrementally reconstructing a 3D scene. However, it localizes a camera to an arbitrary local coordinate system and produces a low-resolution and noisy point cloud that is not suitable for quality assessment of a structure. For the architecture/engineering/construction industry, the better and realistic approach is to localize with respect to building information models (BIMs) in real-time and post-process 3D dense reconstruction. This approach will allow project management teams to better communicate quality and progress using visuals associated with locations shown with BIMs. Moreover, it will automate images-to-BIM and image-based point clouds-to-BIM registration, enhancing past studies that attempt to automate image-based progress detection and quality assessment. On the other hand, the current state-of-the-art method for registering an image-based point cloud to a BIM requires selection of the correspondences. To address these challenges and achieve automation, this paper presents a new localization method that aligns an image to a BIM by detecting and matching perspectives of the image and the BIM. The results demonstrate the potential for enabling automated visual data collection (as-built aligned with as-planned) for performance monitoring. C2 - 2017/6/22/ C3 - Computing in Civil Engineering 2017 DA - 2017/6/22/ DO - 10.1061/9780784480830.022 SP - 171-178 UR - http://dx.doi.org/10.1061/9780784480830.022 ER - TY - CONF TI - Influence of initial and welding residual stresses on low cycle fatigue and ratcheting response simulations of elbows AU - Islam, N. AU - Hassan, T. AB - Earlier studies [1] showed that the ANSYS software package customized with an advanced rate-independent constitutive model was unable to simulate some of the low-cycle fatigue responses of elbow components. Hence, simulations are performed to investigate the influence of manufacturing and welding residual stresses on elbow low-cycle fatigue responses. The sequentially coupled thermo-mechanical finite element analysis is performed to determine the initial residual stress states in elbows due to the elbow manufacturing processes and welding of elbows to straight pipes. Real-time girth-welding processes are taken into account to simulate the welding induced residual stress field. Incorporating these initial residual stresses in the computations, low-cycle fatigue and strain ratcheting responses are simulated by ANSYS. The simulation responses demonstrate that the influence of manufacturing and welding residual stresses in elbows on its low-cycle fatigue responses is negligible. Hence, the question remains what is missing in the simulation models that some of the elbow low-cycle fatigue responses cannot be simulated. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference, 2017, vol 8 DA - 2017/// DO - 10.1115/pvp2017-65847 ER - TY - JOUR TI - Freeway work zone free-flow speed model development AU - Yeom, C. AU - Hajbabaie, A. AU - Rouphail, N.M. AU - Rasdorf, W. AU - Schroeder, B.J. T2 - ITE Journal (Institute of Transportation Engineers) DA - 2017/// PY - 2017/// VL - 87 IS - 11 SP - 38-44 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85044119212&partnerID=MN8TOARS ER - TY - CONF TI - Development of Immersive Personalized Training Environment for Construction Workers AU - Jeelani, I. AU - Han, K. AU - Albert, A. AB - The ability of workers to recognize and manage construction hazards is essential for effective safety management. However, studies have unanimously demonstrated that a large proportion of construction hazards remain unrecognized in dynamic work environments. Such poor hazard recognition levels have been partly attributed to the pervasive use of unengaging and ineffective training practices within construction. To improve training effectiveness, recent efforts have focused on assessing the learning needs of particular workers, and customizing training experiences accordingly to maximize training outcomes. This paper builds upon the previous research by developing an immersive safety training environment that provide a more effective personalized training experience for workers. After development, the degree of realism and immersive experience offered by the training environment was measured and found to be 73% of the real environment. The findings of this study will be useful to practicing professionals seeking to improve training efforts are safety training outcomes. C2 - 2017/6/22/ C3 - Computing in Civil Engineering 2017 DA - 2017/6/22/ DO - 10.1061/9780784480830.050 SP - 407-415 UR - http://dx.doi.org/10.1061/9780784480830.050 ER - TY - CONF TI - Cost-benefit assessment challenges for a smart distribution system: A case study AU - Sun, L. S. AU - Thomas, J. AU - Singh, S. AU - Li, D. X. AU - Baran, M. AU - Lubkeman, D. AU - DeCarolis, J. AU - Queiroz, A. R. AU - White, L. AU - Watts, S. AB - The FREEDM system is a technology for a smarter and resilient distribution system that facilitates a higher level of distributed energy resource (DER) integration by offering effective voltage regulation, reactive power compensation and real time monitoring and control. This paper provides a framework for conducting a cost-benefit analysis for such a smart distribution system. The method first identifies the benefits, and then quantifies and monetizes them. OpenDSS time-series based power flow simulation is used to quantify the benefits accurately. The costs associated with the new components of the system are estimated based on prototype units. A cost-benefit analysis is adopted to identify the scenarios where employing such a system by a utility becomes economically attractive. C2 - 2017/// C3 - 2017 ieee power & energy society general meeting DA - 2017/// DO - 10.1109/pesgm.2017.8274167 ER - TY - JOUR TI - Advances in travel time reliability monitoring and assessment AU - List, George F. AU - Williams, Billy T2 - JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS AB - Travel time reliability has become a subject of increasingly intense interest for researchers and practitioners. Carriers and shippers have focused on reliability in terms of operational control ev... DA - 2017/// PY - 2017/// DO - 10.1080/15472450.2017.1403536 VL - 21 IS - 6 SP - 435-438 SN - 1547-2442 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85041098125&partnerID=MN8TOARS ER - TY - JOUR TI - Characterizing Strength and Failure of Calcium Silicate Hydrate Aggregates in Cement Paste under Micropillar Compression AU - Shahrin, Rahnuma AU - Bobko, Christopher P. T2 - JOURNAL OF NANOMECHANICS AND MICROMECHANICS AB - A new methodology is proposed for investigating compressive failure behavior of cement paste at the micrometer scale. Micropillar geometries are fabricated by focused ion-beam milling on potential calcium-silicate-hydrate (C-S-H) locations identified through energy dispersive spectroscopy (EDS) spot analysis. Uniaxial compression testing of these pillars is performed using nanoindentation equipment. The compressive strength of C-S-H aggregates (225–606 MPa) measured from microcompression tests is found to be consistent with values from multiscale damage and molecular dynamic models. From posttest images, two primary deformation mechanisms at failure were identified; axial splitting and plastic collapse of the entire sample were observed. DA - 2017/12// PY - 2017/12// DO - 10.1061/(asce)nm.2153-5477.0000137 VL - 7 IS - 4 SP - SN - 2153-5477 ER - TY - JOUR TI - Modeling the Role of Social Networks on Hazard Recognition and Communication AU - Albert, Alex AU - Hallowell, Matthew R. T2 - PRACTICE PERIODICAL ON STRUCTURAL DESIGN AND CONSTRUCTION AB - Proper hazard recognition and communication are fundamental to injury prevention in construction. When construction hazards remain unrecognized, the likelihood of injuries in the workplace increases. Therefore, construction employers encourage their workers to actively participate in prejob safety meetings to facilitate the recognition, communication, and management of potential safety hazards. However, field-level hazard communication challenges, including ineffective communication channels, differences in language proficiency, and poor safety climate, are significant impediments to effective safety management. In this study, social network analysis was adopted to evaluate the relationship between safety communication patterns among workers and hazard-recognition performance. Specifically, (1) crew-level safety interaction data were compiled for 18 active crews representing six diverse projects in the United States, (2) the hazard-recognition performance of the participating crews was measured though field observatory studies, and (3) the relationship between social interactions and hazard-recognition performance was assessed using social network methods. The research findings suggest that well-connected crews with higher numbers of safety communication ties (i.e., network density) collectively recognize a larger proportion of hazards compared to those crews with fewer ties. Moreover, supervisor centrality in safety communication patterns differentiate crews with higher hazard-recognition levels from their lower-performance counterparts. The findings highlight the importance of network patterns in the communication of construction hazards. DA - 2017/11// PY - 2017/11// DO - 10.1061/(asce)sc.1943-5576.0000337 VL - 22 IS - 4 SP - SN - 1943-5576 ER - TY - JOUR TI - Heat Generation and Accumulation in Municipal Solid Waste Landfills AU - Hao, Zisu AU - Sun, Mei AU - Ducoste, Joel J. AU - Benson, Craig H. AU - Luettich, Scott AU - Castaldi, Marco J. AU - Barlaz, Morton A. T2 - Environmental Science & Technology AB - There have been reports of North American landfills that are experiencing temperatures in excess of 80-100 °C. However, the processes causing elevated temperatures are not well understood. The objectives of this study were to develop a model to describe the generation, consumption and release of heat from landfills, to predict landfill temperatures, and to understand the relative importance of factors that contribute to heat generation and accumulation. Modeled heat sources include energy from aerobic and anaerobic biodegradation, anaerobic metal corrosion, ash hydration and carbonation, and acid-base neutralization. Heat removal processes include landfill gas convection, infiltration, leachate collection, and evaporation. The landfill was treated as a perfectly mixed batch reactor. Model predictions indicate that both anaerobic metal corrosion and ash hydration/carbonation contribute to landfill temperatures above those estimated from biological reactions alone. Exothermic pyrolysis of refuse, which is hypothesized to be initiated due to a local accumulation of heat, was modeled empirically to illustrate its potential impact on heat generation. DA - 2017/10/11/ PY - 2017/10/11/ DO - 10.1021/acs.est.7b01844 VL - 51 IS - 21 SP - 12434-12442 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.7b01844 DB - Crossref ER - TY - JOUR TI - Designing local solutions for emptying pit latrines in low-income urban settlements (Malawi) AU - Chipeta, W.C. AU - Holm, R.H. AU - Kamanula, J.F. AU - Mtonga, W.E. AU - de los Reyes, F.L., III T2 - Physics and Chemistry of the Earth, Parts A/B/C AB - A lack of effective options in local technology poses challenges when onsite household sanitation facilities are eventually filled to capacity in unplanned settlement areas within Mzuzu City, located in northern Malawi. Vacuum trucks currently dominate the market but focus on emptying septic tanks in the more easily accessible planned settlement areas, rather than servicing the pit latrines common in unplanned settlement areas. As a result, households in the unplanned settlement areas within Mzuzu rely primarily on manual pit emptying (i.e., shoveling by hand) or digging a new pit latrine. These practices have associated health risks and are limited by space constraints. This research focused on filling the technological gap through the design, development, and testing of a pedal powered modified Gulper pump using locally available materials and fabrication. A modified pedal powered Gulper technology was developed and demonstrated to be capable of lifting fecal sludge from a depth of 1.5 m with a mean flow rate of 0.00058 m3/s. If the trash content was low, a typical pit latrine with a volume of 1-4 m3 could be emptied within 1-2 h. Based on the findings in our research Phase IV, the pedal powered Gulper modification is promising as a potential emptying technology for lined pit latrines in unplanned settlement areas. The success rate of the technology is about 17% (5 out 30 sampled lined pit latrines were successful) and reflects the difficulty in finding a single technology that can work well in all types of pit latrines with varying contents. We note that cost should not be the only design criteria and acknowledge the challenge of handling trash in pit latrines. DA - 2017/8// PY - 2017/8// DO - 10.1016/j.pce.2017.02.012 VL - 100 SP - 336-342 J2 - Physics and Chemistry of the Earth, Parts A/B/C LA - en OP - SN - 1474-7065 UR - http://dx.doi.org/10.1016/j.pce.2017.02.012 DB - Crossref KW - Fecal sludge management KW - Gulper KW - Low-income countries KW - Pit emptying KW - Technology KW - Unplanned settlement areas ER - TY - JOUR TI - Perspectives of the Journal of Construction Engineering and Management Spanning Three Decades AU - Rowings, James E. AU - Jahren, Charles T. AU - Jaselskis, Edward J. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. DA - 2017/9// PY - 2017/9// DO - 10.1061/(asce)co.1943-7862.0001380 VL - 143 IS - 9 SP - SN - 1943-7862 ER - TY - JOUR TI - Performance enhancement of eight bolt extended end-plate moment connections under simulated seismic loading AU - Morrison, Machel AU - Quayyum, Shahriar AU - Hassan, Tasnim T2 - ENGINEERING STRUCTURES AB - Extended end-plate (EEP) moment resisting connections provide the advantage of eliminating field welding and by virtue of this, facilitate fast field erection of building frames. The eight bolt stiffened (8ES) EEP connection is one of the prequalified moment connections in the AISC 358 standard for special moment frames (SMFs) in seismic regions. In this connection, a stiffener plate is welded between the end plate and the beam flanges to strengthen the extended portion of the end plate. This stiffener reduces prying action and more uniformly distributes flange forces among the bolt group. In experimental studies, the 8ES connection has shown ductile response to simulated seismic loading with test specimens typically failing due to beam buckling and gradual strength degradation. However, cracks initiating at the toe of the stiffener leading to brittle fracture of the beam flange has also been observed due to the high stress concentration in this region. The study reported herein proposes an eight-bolt EEP connection in which the end plate stiffener is removed and the bolt arrangement is modified to promote uniform distribution of flange forces among the bolt group. The proposed connection was developed through detailed finite element analysis in which various bolt arrangements for stiffened and unstiffened eight-bolt EEP connections were considered. The proposed connection displayed reduced beam flange stress and strain concentrations, delayed or reduced rate of strength degradation from local buckling and more uniform distribution of bolt forces when compared to the alternatives. Furthermore, when compared to the currently prequalified 8ES connection, despite requiring thicker end plates, the proposed connection is anticipated to result in cost savings from the removal of the end plate stiffener. Future analytical and experimental needs for further development of the proposed connection are discussed. DA - 2017/11/15/ PY - 2017/11/15/ DO - 10.1016/j.engstruct.2017.08.040 VL - 151 SP - 444-458 SN - 1873-7323 KW - Extended end-plate connection KW - Modified bolt arrangement KW - End plate stiffener KW - Stress concentration ER - TY - JOUR TI - Impact of climate change on pavement structural performance in the United States AU - Gudipudi, Padmini P. AU - Underwood, B. Shane AU - Zalghout, Ali T2 - Transportation Research Part D: Transport and Environment AB - This study uses climate projections from multiple models and for different climate regions to investigate how climate change may impact the transportation infrastructure in the United States. Climate data from both an ensemble of 19 different climate models at both RCP8.5 and RCP4.5 as well as three individual prediction models at the same Representative Concentration Pathways (RCP) levels is used. These models are integrated into the AASHTOWare Pavement ME software to predict the pavement performance. Comparisons are made between the predicted performance with respect to typical pavement distresses using both historical climate data as well as climate projection data. Though there is substantial variation for different prediction models in terms of the magnitude of the impact, the consistency in results suggest that projected climate changes are highly likely to result in greater distresses and/or earlier failure of the pavement. This finding is consistent across all the climate zones studied, but varies in magnitude of 2–9% for fatigue cracking and 9–40% for AC rutting at the end of 20 years depending on the climate region of the pavement section and prediction model used. This study also compares the impacts incorporating temperature only projections with temperature and precipitation projections. In this respect, the sections considered in this study do not show any substantial difference in the pavement performance when the precipitation data from the climate predictions are also considered in the climate inputs into AASHTOWare Pavement ME software. DA - 2017/12// PY - 2017/12// DO - 10.1016/j.trd.2017.09.022 VL - 57 SP - 172-184 J2 - Transportation Research Part D: Transport and Environment LA - en OP - SN - 1361-9209 UR - http://dx.doi.org/10.1016/j.trd.2017.09.022 DB - Crossref KW - Climate change KW - AASHTOWare pavement ME software KW - Pavement performance KW - CMIP5 KW - Impact assessment ER - TY - JOUR TI - Estimation of Site‐Specific Kappa (κ0)‐Consistent Damping Values at KiK‐Net Sites to Assess the Discrepancy between Laboratory‐Based Damping Models and Observed Attenuation (of Seismic Waves) in the Field AU - Cabas, Ashly AU - Rodriguez‐Marek, Adrian AU - Bonilla, Luis Fabian T2 - Bulletin of the Seismological Society of America AB - Research Article| September 25, 2017 Estimation of Site‐Specific Kappa (⁠κ0⁠)‐Consistent Damping Values at KiK‐Net Sites to Assess the Discrepancy between Laboratory‐Based Damping Models and Observed Attenuation (of Seismic Waves) in the Field Ashly Cabas; Ashly Cabas aNorth Carolina State University, 2501 Stinson Drive, Mann Hall, Room 425A, Raleigh, North Carolina 27607, amcabasm@ncsu.edu Search for other works by this author on: GSW Google Scholar Adrian Rodriguez‐Marek; Adrian Rodriguez‐Marek bVirginia Tech, 750 Drillfield Drive, Patton Hall, Room 214, Blacksburg, Virginia 24061 Search for other works by this author on: GSW Google Scholar Luis Fabian Bonilla Luis Fabian Bonilla cUniversité Paris Est—IFSTTAR, Laboratoire Séismes et Vibrations, 14‐20 Boulevard Newton, Cité Descartes, Champs sur Marne, F‐77447 Marne la Vallée, Cedex 2, France Search for other works by this author on: GSW Google Scholar Author and Article Information Ashly Cabas aNorth Carolina State University, 2501 Stinson Drive, Mann Hall, Room 425A, Raleigh, North Carolina 27607, amcabasm@ncsu.edu Adrian Rodriguez‐Marek bVirginia Tech, 750 Drillfield Drive, Patton Hall, Room 214, Blacksburg, Virginia 24061 Luis Fabian Bonilla cUniversité Paris Est—IFSTTAR, Laboratoire Séismes et Vibrations, 14‐20 Boulevard Newton, Cité Descartes, Champs sur Marne, F‐77447 Marne la Vallée, Cedex 2, France Publisher: Seismological Society of America First Online: 27 Sep 2017 Online Issn: 1943-3573 Print Issn: 0037-1106 Bulletin of the Seismological Society of America (2017) 107 (5): 2258–2271. https://doi.org/10.1785/0120160370 Article history First Online: 27 Sep 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Ashly Cabas, Adrian Rodriguez‐Marek, Luis Fabian Bonilla; Estimation of Site‐Specific Kappa (⁠κ0⁠)‐Consistent Damping Values at KiK‐Net Sites to Assess the Discrepancy between Laboratory‐Based Damping Models and Observed Attenuation (of Seismic Waves) in the Field. Bulletin of the Seismological Society of America 2017;; 107 (5): 2258–2271. doi: https://doi.org/10.1785/0120160370 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract In this article, we compare field estimates of near‐surface attenuation, as captured by site‐specific κ‐values (i.e., κ0⁠) with laboratory‐based estimates of minimum shear‐strain damping (⁠ξmin⁠). We propose models for ξmin based on κ0 measured at selected stations of the KiK‐net database, which are found to be generally larger than low‐strain damping values obtained from laboratory testing. The latter can only quantify intrinsic material damping, whereas other attenuation mechanisms such as scattering of the wavefield contribute to field‐based estimates. In addition, we evaluate the difference in damping at the surface and at borehole stations to determine the contribution of shallow layers to attenuation as captured by κ0‐values at the surface. Thus, values of κ0 are computed at the surface and at the downhole instrument depth. The difference between both values, Δκ⁠, correlates well with the averaged shear‐wave velocity over the top 30 m of the profile, VS30⁠, and with the depth to bedrock. Estimates of κ0 for hard‐rock and stiff sites in Japan are also examined and compared with other regional κ0‐values proposed for high VS30 materials in New Zealand, Greece, and Switzerland. Two values of κ0⁠, which are lower than the corresponding estimates for the aforementioned regions, are deemed potential descriptors of hard‐rock conditions in Japan. The ability of the proposed κ0‐consistent damping models to predict ground motions using the vertical array data from the KiK‐net sites has yet to be tested. You do not have access to this content, please speak to your institutional administrator if you feel you should have access. DA - 2017/9/25/ PY - 2017/9/25/ DO - 10.1785/0120160370 VL - 107 IS - 5 SP - 2258-2271 LA - en OP - SN - 0037-1106 1943-3573 UR - http://dx.doi.org/10.1785/0120160370 DB - Crossref ER - TY - JOUR TI - Dispersion analysis of composite acousto-elastic waveguides AU - Astaneh, Ali Vaziri AU - Guddati, Murthy N. T2 - COMPOSITES PART B-ENGINEERING AB - Abstract Propagation characteristics of guided waves are widely utilized for nondestructive characterization of laminated composites which are often immersed in fluid. These propagation characteristics are quantified through dispersion and attenuation curves, and need to be computed for a large number of estimated structure and material property combinations, over a wide range of frequencies. To solve this central problem, an efficient approach is proposed for dispersion analysis of three types of immersed waveguides: laminated plates; laminated rods and pipes; composite waveguides with generic cross-section. The approach is based on Semi-Analytical Finite Element (SAFE) method enhanced with two novel discretization methods: Complex-length Finite Element Method (CFEM) for the solid domain and Perfectly Matched Discrete Layers (PMDL) for the surrounding fluid. The resulting approach is computationally more efficient than the existing methods in that it keeps the underlying eigenvalue problem linear and substantially smaller. The paper presents the basic ideas of the proposed approach, specific algorithms for determining the discretization parameters, and open-source implementation of the resulting waveguide models. Several numerical examples are presented to illustrate the method's efficiency. Finally, the theoretical predictions from the method are validated using experimental observations for several structural members. DA - 2017/12/1/ PY - 2017/12/1/ DO - 10.1016/j.compositesb.2017.07.040 VL - 130 SP - 200-216 SN - 1879-1069 KW - Layered structures KW - Laminates KW - Computational modeling KW - Non-destructive testing ER - TY - JOUR TI - Development of Stress Sweep Rutting (SSR) test for permanent deformation characterization of asphalt mixture AU - Kim, Dahae AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The goal of this work is to develop a simple rutting test method, referred to as the Stress Sweep Rutting (SSR) test, which can be used to calibrate a permanent deformation model, known as the shift model, of asphalt mixtures. The effect of each shift model parameter, i.e., temperature, deviatoric stress, load time, and rest period, on permanent deformation has been explored and evaluated in an effort to minimize the test requirements of the rutting characterization. The accuracy of the SSR test method was evaluated using the Layered ViscoElastic pavement analysis for Critical Distresses (LVECD) program by predicting the permanent deformation and compared to the Triaxial Stress Sweep (TSS) method, which was originally developed to calibrate the shift model. The rut depths predicted from the SSR and TSS method using the LVECD program are in close agreement, thereby verifying the SSR test method. DA - 2017/11/15/ PY - 2017/11/15/ DO - 10.1016/j.conbuildmat.2017.07.172 VL - 154 SP - 373-383 SN - 1879-0526 KW - Asphalt materials KW - Rutting KW - Permanent deformation KW - TSS KW - SSR KW - Flow number ER - TY - JOUR TI - An Empirical Agent-Based Model to Simulate the Adoption of Water Reuse Using the Social Amplification of Risk Framework AU - Kandiah, Venu AU - Binder, Andrew R. AU - Berglund, Emily Z. T2 - Risk Analysis AB - Abstract Water reuse can serve as a sustainable alternative water source for urban areas. However, the successful implementation of large‐scale water reuse projects depends on community acceptance. Because of the negative perceptions that are traditionally associated with reclaimed water, water reuse is often not considered in the development of urban water management plans. This study develops a simulation model for understanding community opinion dynamics surrounding the issue of water reuse, and how individual perceptions evolve within that context, which can help in the planning and decision‐making process. Based on the social amplification of risk framework, our agent‐based model simulates consumer perceptions, discussion patterns, and their adoption or rejection of water reuse. The model is based on the “risk publics” model, an empirical approach that uses the concept of belief clusters to explain the adoption of new technology. Each household is represented as an agent, and parameters that define their behavior and attributes are defined from survey data. Community‐level parameters—including social groups, relationships, and communication variables, also from survey data—are encoded to simulate the social processes that influence community opinion. The model demonstrates its capabilities to simulate opinion dynamics and consumer adoption of water reuse. In addition, based on empirical data, the model is applied to investigate water reuse behavior in different regions of the United States. Importantly, our results reveal that public opinion dynamics emerge differently based on membership in opinion clusters, frequency of discussion, and the structure of social networks. DA - 2017/1/11/ PY - 2017/1/11/ DO - 10.1111/risa.12760 VL - 37 IS - 10 SP - 2005-2022 J2 - Risk Analysis LA - en OP - SN - 0272-4332 UR - http://dx.doi.org/10.1111/risa.12760 DB - Crossref KW - Acceptance-resistance KW - agent-based model KW - opinion dynamics KW - risk perceptions KW - social amplification of risk KW - water reuse ER - TY - JOUR TI - A mechanistic approach to evaluate the potential of the debonding distress in asphalt pavements AU - Cho, Seong-Hwan AU - Karshenas, Afshin AU - Tayebali, Akhtarhusein A. AU - Guddati, Murthy N. AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - The debonding distress in asphalt pavement structures is a critical problem that affects the performance of asphalt concrete pavements. It occurs at the layer interface due to the poor bond quality between adjacent asphalt concrete layers and/or when stresses at the layer interface exceed the strengths of the material at the interface. The debonding of the adjacent layers, especially the top surface layer of an asphalt pavement, is a contributing factor to the premature cracking of pavements. Hence, the debonding distress can lead to a reduction in the life of the pavement. This paper presents an analytical and experimental framework to evaluate the potential for debonding at the layer interface of asphalt concrete pavements. Computational analysis was performed to determine the critical stress and strain states in layered asphalt pavements under moving vehicle loads using the Layered ViscoElastic pavement analysis for Critical Distresses (LVECD) computer program developed at North Carolina State University. This computational analysis enables a greater understanding of the critical stress that is involved in debonding and the ways that such stress is affected by pavement design parameters and environmental conditions. In addition, a prediction model was developed that can determine the shear bond strength at the interface of asphalt concrete layers with different tack coat materials at various temperatures, loading rates and normal confining stresses. The systematic and mechanistic framework developed in this study employs the maximum shear ratio concept as a shear failure criterion and provides a tool to evaluate the effects of various loading, environmental and pavement factors on the debonding potential of asphalt pavements. The overall advantages of the mechanistic framework and approach using the LVECD analysis tool will help lead to better understanding of the debonding mechanism, proper selection of the tack coats, and economic benefit in highway pavement maintenance and rehabilitation costs. DA - 2017/// PY - 2017/// DO - 10.1080/10298436.2016.1149837 VL - 18 IS - 12 SP - 1098-1110 SN - 1477-268X KW - Debonding KW - LVECD KW - critical stress KW - shear bond strength KW - maximum shear ratio (MSR) ER - TY - JOUR TI - A framework to characterize the healing potential of asphalt binder using the linear amplitude sweep test AU - Xie, Wei AU - Castorena, Cassie AU - Wang, Chao AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The healing characteristics of asphalt binders affect the fatigue performance of asphalt mixtures and field pavements. The objective of this paper is to quantify the healing potential of asphalt binders using the linear amplitude sweep (LAS) test under various damage level and rest period durations. A healing protocol based on the LAS test is successfully established to measure the healing behaviour of asphalt binder by applying the rest periods before and after cohesive failure. Based on the simplified-viscoelastic continuum damage (S-VECD) model, the percent healing (%HS) is quantified from the healing recovery of the accumulated damage growths. The neat asphalt binder exhibits better %HS results than the SBS modified binder in the pre-failure conditions. However, the SBS modified binder exhibits a higher healing potential in the post-failure case. The rest-damage superposition principle (RDSP) is further investigated in the pre-failure cases to remove and unify the effects of damage level and rest period by constructing a %HS mastercurve at a given reference damage level. The developed healing mastercurve and related damage shift factor can be used to represent the intrinsic healing potential of a given asphalt binder. A series of healing indices are proposed and discussed based on the healing mastercurve to numerically compare the healing performance of asphalt binders. DA - 2017/11/15/ PY - 2017/11/15/ DO - 10.1016/j.conbuildmat.2017.08.021 VL - 154 SP - 771-779 SN - 1879-0526 KW - Asphalt binder KW - Fatigue damage KW - Rest period KW - Healing mastercurve KW - Healing index ER - TY - JOUR TI - A critical review of fat, oil, and grease (FOG) in sewer collection systems: Challenges and control AU - He, Xia AU - de los Reyes, Francis L., III AU - Ducoste, Joel J. T2 - Critical Reviews in Environmental Science and Technology AB - Fat, oil, and grease (FOG) released into the sewer collection system have resulted in the production of insoluble solids, leading to FOG blockages in sanitary sewer pipes and consequently sanitary sewer overflows (SSOs). FOG-related SSOs continue to be a global challenge for municipalities responsible for maintaining the conveyance of wastewater in sanitary sewer systems. To provide a comprehensive understanding of FOG control in sewers, this paper critically reviews the scientific literature on the FOG deposit formation process, sources of components involved in FOG deposit formation, and solutions to the problems caused by FOG in sewer systems. The implications of these findings were also evaluated to provide support for pretreatment managers responsible for sewer collection system maintenance. Finally, the ongoing challenges in further understanding the FOG deposit formation process, the distribution of the sources of FOG/free fatty acids, the installation and maintenance of grease interceptors (GIs), and the recovery of energy from GI waste and FOG deposits, were also discussed to determine future research directions. DA - 2017/7/3/ PY - 2017/7/3/ DO - 10.1080/10643389.2017.1382282 VL - 47 IS - 13 SP - 1191-1217 J2 - Critical Reviews in Environmental Science and Technology LA - en OP - SN - 1064-3389 1547-6537 UR - http://dx.doi.org/10.1080/10643389.2017.1382282 DB - Crossref KW - Fat; oil; grease (FOG) KW - sewer blockage KW - sanitary sewer overflows (SSOs) ER - TY - JOUR TI - Thermo-mechanical low-cycle fatigue-creep of Haynes 230 AU - Ahmed, Raasheduddin AU - Barrett, Paul Ryan AU - Menon, Mamballykalathil AU - Hassan, Tasnim T2 - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES AB - • Developed a broad set of thermo-mechanical fatigue-creep (TMFC) responses of a superalloy. • Demonstration of the influence of TMFC loading on mean stress evolution. • Demonstration of the influence of TMFC loading on the elastic modulus rate change. • Discussion on the challenges in constitutive model development for TMFC responses. • Comparison of isothermal and thermo-mechanical fatigue-creep lives. Combustor liners of airplane gas turbine engines experience premature thermo-mechanical fatigue-creep (TMFC) failure under operational loading conditions. The loading history of combustor liners encompass temperature fluctuation between ambient to as high as 1000 °C, and concurrent strain or stress fluctuation with load peak dwell-periods of 30 min to as long as 16 h of flying time. Repetition of such an anisothermal loading history leads to crack initiation in components via TMFC damage accumulation processes. In an effort to investigate such TMFC failures, a set of anisothermal experiments, both in-phase and out-of-phase, with peak dwell periods, were carried out for Haynes 230, a nickel-based superalloy used in constructing combustor liners. Analysis of the responses from out-of-phase experiments with compression dwells show mean-stress evolution in the tensile direction, while that from in-phase experiments with tensile dwells show mean-stress evolution in the compression direction. The total stress relaxation during peak strain dwell in the TMFC loading in general decreases with cycle, whereas that in the isothermal low-cycle fatigue-creep (LCFC) increases with cycle. The cyclic hardening-softening response is found to depend on the maximum temperature in the TMFC loading cycle. While calculating the inelastic strain in the experiments, it was found that the time derivative of the elastic modulus needed to be considered to prevent anomalous shifting of the hysteresis loops with cycles. The fatigue lives in the TMFC experiments are adversely affected by higher maximum temperatures and longer dwell-periods. These experimental responses are presented and analyzed, and challenges in developing a unified constitutive model for simulation of these responses are identified. DA - 2017/11// PY - 2017/11// DO - 10.1016/j.ijsolstr.2017.07.033 VL - 126 SP - 90-104 SN - 1879-2146 KW - Haynes 230 KW - Anisothermal fatigue KW - Mean-stress evolution KW - Stress relaxation KW - Thermomechanical fatigue-creep ER - TY - JOUR TI - Relationship Between Total and Bioaccessible Lead on Children's Blood Lead Levels in Urban Residential Philadelphia Soils AU - Bradham, Karen D. AU - Nelson, Clay M. AU - Kelly, Jack AU - Pomales, Ana AU - Scruton, Karen AU - Dignam, Tim AU - Misenheimer, John C. AU - Li, Kevin AU - Obenour, Daniel R. AU - Thomas, David J. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Relationships between total soil or bioaccessible lead (Pb), measured using an in vitro bioaccessibility assay, and children’s blood lead levels (BLL) were investigated in an urban neighborhood in Philadelphia, PA, with a history of soil Pb contamination. Soil samples from 38 homes were analyzed to determine whether accounting for the bioaccessible Pb fraction improves statistical relationships with children’s BLLs. Total soil Pb concentration ranged from 58 to 2821 mg/kg; the bioaccessible Pb concentration ranged from 47 to 2567 mg/kg. Children’s BLLs ranged from 0.3 to 9.8 μg/dL. Hierarchical models were used to compare relationships between total or bioaccessible Pb in soil and children’s BLLs. Total soil Pb concentration as the predictor accounted for 23% of the variability in child BLL; bioaccessible soil Pb concentration as the predictor accounted for 26% of BLL variability. A bootstrapping analysis confirmed a significant increase in R2 for the model using bioaccessible soil Pb concentration as the predictor with 99.0% of bootstraps showing a positive increase. Estimated increases of 1.3 μg/dL and 1.5 μg/dL in BLL per 1000 mg/kg Pb in soil were observed for this study area using total and bioaccessible Pb concentrations, respectively. Children’s age did not contribute significantly to the prediction of BLLs. DA - 2017/9/5/ PY - 2017/9/5/ DO - 10.1021/acs.est.7b02058 VL - 51 IS - 17 SP - 10005-10011 SN - 1520-5851 ER - TY - JOUR TI - Natural and enhanced attenuation of explosives on a hand grenade range AU - Borden, R. C. AU - Won, J. AU - Yuncu, B. T2 - Journal of Environmental Quality DA - 2017/// PY - 2017/// VL - 46 IS - 5 SP - 961-967 ER - TY - JOUR TI - Material nonlinearity in asphalt binder fatigue testing and analysis AU - Safaei, Farinaz AU - Castorena, Cassie T2 - MATERIALS & DESIGN AB - Fatigue cracking is a primary distress in asphalt pavements caused by the accumulation of damage under repeated traffic loading. Asphalt binder is the weakest constituent of asphalt mixture. Therefore, the inherent fatigue resistance of the asphalt binder contained within the pavement is anticipated to influence pavement performance. The simplified viscoelastic continuum damage (S-VECD) model has been applied to predict fatigue life of asphalt binders under varying loading and thermal conditions using time sweep and linear amplitude sweep (LAS) test results. The majority of past efforts using S-VECD analysis protocol have neglected the effects of material nonlinearity and attributed all material integrity loss to damage for the sake of simplicity. Herein, experimental and analytical methods are evaluated for delineating damage and nonlinearity in fatigue testing of asphalt binder. None of the experimental methods evaluated enabled accurate separation of damage and nonlinearity at the high strain amplitudes included in LAS tests. Therefore, an analytical method using S-VECD modeling was proposed to back calculate nonlinear dynamic shear moduli from LAS test results. Results can be used to generate a nonlinear S-VECD model which allows for improved fatigue life predictions. DA - 2017/11/5/ PY - 2017/11/5/ DO - 10.1016/j.matdes.2017.08.010 VL - 133 SP - 376-389 SN - 1873-4197 UR - https://doi.org/10.1016/j.matdes.2017.08.010 KW - Asphalt binder KW - Fatigue KW - Nonlinearity ER - TY - JOUR TI - Laboratory column evaluation of high explosives attenuation in grenade range soils AU - Won, J. AU - Borden, R. C. T2 - Journal of Environmental Quality DA - 2017/// PY - 2017/// VL - 46 IS - 5 SP - 968-974 ER - TY - JOUR TI - Driver Accuracy in Identifying Food and Attraction Targets on Business Logo Signs Impacts of Driver Age, Number of Panels, Logo Familiarity, and Logo Format AU - Rasdorf, William AU - Machado, Patricia AU - Hummer, Joseph E. AU - Kaber, Dave AU - Zahabi, Maryam AU - Lau, Mei AU - Pankok, Carl T2 - TRANSPORTATION RESEARCH RECORD AB - The standard business logo sign found along North Carolina highways contains six logos, in accordance with the Manual on Uniform Traffic Control Devices. As the population grows, the demand for business is increasing. Shifting from six-panel business logo signs to nine-panel signs would afford more businesses the opportunity to advertise in areas of high demand. The effects that such a change may have on the driving population are analyzed. Factors such as a driver’s age and familiarity with logos and logo format are taken into consideration. A change in the format of business logo signs is proposed not only to move from six to nine panels but also to improve the effectiveness of existing business logo signs. DA - 2017/// PY - 2017/// DO - 10.3141/2624-02 IS - 2624 SP - 9-17 SN - 2169-4052 ER - TY - JOUR TI - Detection and localization of changes in two-dimensional temperature distributions by electrical resistance tomography AU - Rashetnia, Reza AU - Hallaji, Milad AU - Smyl, Danny AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - SMART MATERIALS AND STRUCTURES AB - This paper studies the feasibility of applying electrical resistance tomography (ERT) to detect changes in two-dimensional (2D) temperature distributions with potential applications in sensor development. The proposed sensor consists of a thin layer of porous metal film manufactured by spraying colloidal copper paint to a solid surface. A change of the temperature distribution on the surface changes the 2D distributed electrical conductivity of the metal film. The change of the electrical conductivity is localized and quantified with ERT, and further, to convert the estimated conductivity change of the sensor to temperature change, an experimentally developed model is used. The proposed temperature sensor is evaluated experimentally by applying it to a polymeric substrate, and exposing it to known temperature changes using heat sources of different shapes. The results demonstrate that the proposed sensor is capable of detecting and localizing temperature changes, and provides at least qualitative information on the magnitude of the temperature change. DA - 2017/11// PY - 2017/11// DO - 10.1088/1361-665x/aa8f75 VL - 26 IS - 11 SP - SN - 1361-665X KW - absolute imaging KW - electrical impedance tomography (EIT) KW - inverse problems KW - sensing skin KW - two-dimensional temperature sensor ER - TY - JOUR TI - Constitutive modeling for thermo-mechanical low-cycle fatigue-creep stress-strain responses of Haynes 230 AU - Ahmed, Raasheduddin AU - Hassan, Tasnim T2 - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES AB - • Unified constitutive modeling for thermomechanical fatigue-creep (TMFC) responses. • Illustration of the need of advancing constitutive modeling for TMFC responses. • Experimental validation of the modified model against a broad set of TMFC responses. • Discussion and performance illustration of the modified modeling features. • Demonstration of significant progress in unified constitutive modeling. Haynes 230 (HA 230), a Nickel-based superalloy, is the primary material of combustor liners in airplane gas turbine engines. This component operates in the temperature range between ambient to as high as 1000 °C. Such thermal cycles together with the resulting strain cycles in a combustor liner may induce thermo-mechanical fatigue-creep (TMFC) damage and initiate cracks earlier than the estimated life. Use of a robust unified constitutive model (UCM) for nonlinear analysis based design may improve fatigue life estimation of high temperature components. Available UCMs in the literature or commercial software packages are unable to simulate the TMFC responses reasonably. Hence, this study developed a UCM incorporating the modeling features of rate and temperature dependence, static-recovery, various kinematic hardening evolutions, and strain-range dependence, and validated the model against a broad set of TMFC experimental responses of HA 230. This modified UCM is capable of simulating the mean-stress evolution under both the out-of-phase and in-phase TMFC loading cycles. The modified UCM can adequately simulate most of the characteristic cyclic phenomena of HA 230 including the influence of maximum temperature on the out-of-phase and in-phase TMFC hysteretic responses, stress amplitude, and stress relaxation during strain-dwell. The time-derivative of the elastic modulus is an essential modeling feature for accurately simulating the inelastic strains under TMFC loading. These simulations demonstrate the progresses made in UCM. DA - 2017/11// PY - 2017/11// DO - 10.1016/j.ijsolstr.2017.07.031 VL - 126 SP - 122-139 SN - 1879-2146 KW - Cyclic viscoplasticity KW - Unified constitutive model KW - Thermo-mechanical fatigue-creep KW - Mean-stress evolution KW - Stress relaxation KW - Haynes 230 ER - TY - JOUR TI - Comparing the performance of fiberglass grid with composite interlayer systems in asphalt concrete AU - Wargo, A. AU - Safavizadeh, S. A. AU - Kim, Y. R. T2 - Transportation Research Record DA - 2017/// PY - 2017/// IS - 2631 SP - 123-132 ER - TY - JOUR TI - Can the dual-permeability model be used to simulate unsaturated moisture flow in damaged mortar and concrete? AU - Smyl, Danny AU - Ghasemzadeh, Farnam AU - Pour-Ghaz, Mohammad T2 - International Journal of Advances in Engineering Sciences and Applied Mathematics DA - 2017/3/20/ PY - 2017/3/20/ DO - 10.1007/s12572-017-0180-y VL - 9 IS - 2 SP - 54-66 J2 - Int J Adv Eng Sci Appl Math LA - en OP - SN - 0975-0770 0975-5616 UR - http://dx.doi.org/10.1007/s12572-017-0180-y DB - Crossref KW - Durability KW - Finite element analysis KW - Freezing and thawing KW - Microcracking KW - Transport properties ER - TY - JOUR TI - Asymmetry of the free-standing polyelectrolyte multilayers AU - Yu, Li AU - Yuan, Weichang AU - Liu, Xiaokong AU - Xu, Xintong AU - Ruan, Shuangchen T2 - APPLIED SURFACE SCIENCE AB - Free-standing polyelectrolyte multilayers (PEMs) triggered an intense research effort to develop functional capsules and membranes, nevertheless, the comprehensive understanding of the surface distinctions between the two sides of the free-standing PEMs has been rarely studied. In this paper, we demonstrate the asymmetric surface morphologies, compositions, surface charge and wetting properties of the free-standing PEMs made of alternating deposition of poly(diallyldimethylammonium chloride) (PDDA) and poly(styrenesulfonate) (PSS) on uncharged trimethoxy (octyl) silane modified silicon wafer (TMOS-Si) substrates. The growth behaviors (e.g., linear or exponential growth) of the (PDDA/PSS)n PEMs deposited on TMOS-Si substrates are similar to those deposited on negatively charged substrates except a slower evolution in morphology and thickness, evidenced by atomic force microscopy (AFM) and ellipsometry. The surface charge of the two sides can be tuned as +/+, −/-, and +/− by selecting the first and the terminate layer of the polyelectrolyte during the deposition process, indicated by X-ray photoelectron spectroscopy (XPS) and the surface zeta potential measured by spinning disk method. Further, water contact angle measurements exhibit a strong difference between the back side (the bottom side that was initially contacted with the substrate) (74 ± 4°) and front side (33 ± 2° and 48 ± 3° for PDDA and PSS as the outmost layer, respectively) of the PEMs. The larger water contact angle of the back side is probably resulted from the orientation of the alkyl chains of the polyelectrolytes as the hydrophobic–hydrophobic interactions played significant roles in deposition of a polyelectrolyte onto an uncharged substrate. This paper may gain new insights on understanding surface properties of the PEMs. DA - 2017/11/15/ PY - 2017/11/15/ DO - 10.1016/j.apsusc.2017.05.085 VL - 422 SP - 46-55 SN - 1873-5584 KW - Layer-by-layer assembly KW - Polyelectrolyte multilayers KW - Hydrophobic substrate KW - Free-standing films KW - Asymmetry ER - TY - JOUR TI - V-S-kappa(0) Correction Factors for Input Ground Motions Used in Seismic Site Response Analyses AU - Cabas, Ashly AU - Rodriguez-Marek, Adrian T2 - EARTHQUAKE SPECTRA AB - Input motions used in seismic site response analyses are commonly selected based on similarities between the shear wave velocity ( V S ) at the recording station, and the reference depth at the site of interest (among other aspects such as the intensity of the expected ground motion). This traditional approach disregards the influence of the attenuation in the shallow crust on site response. Given that this attenuation (damping) can be characterized by the distance-independent high-frequency attenuation parameter κ 0 , a V S -κ 0 correction framework for input motions is proposed to render them compatible with the assumed properties of the reference depth at the site. The proposed correction factors were applied to a subset of recordings from the KiK-net database, and compared to traditional deconvolution. Results indicate that V S -κ 0 corrected motions outperform deconvolved motions in the characterization of the spectral energy in the high-frequency range. However, motions recorded at sites with soft deposits are not good candidates for the V S -κ 0 correction approach. V S -κ 0 corrections also affect amplification functions which are important in the assessment of site-specific seismic hazards. DA - 2017/8// PY - 2017/8// DO - 10.1193/22315eqs188m VL - 33 IS - 3 SP - 917-941 SN - 1944-8201 ER - TY - JOUR TI - Use of Microsimulation to Evaluate Signal-Phasing Schemes at Diverging Diamond Interchanges AU - Warchol, Shannon AU - Chase, Thomas AU - Cunningham, Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - Even though diverging diamond interchanges (DDIs) have been the subject of research for more than a decade, the effort to standardize interchange signal timing has developed only recently. A three-factor fully crossed experiment was conducted to investigate the influence of crossover spacing and increased volumes on the performance of DDI phasing schemes. PTV Vistro software and the dynamic bandwidth assessment tool were used to optimize the split, cycle length, and offset of each of the 72 treatments. PTV Vissim software was used to collect microsimulation data. Mean interchange delay and mean stops per vehicle were selected as measures of effectiveness. Pairwise comparisons were used to determine whether an existing preferred phasing scheme could minimize delays or stops under three cases: ( a) given spacing and increased volume, ( b) given volume independent of spacing, and ( c) given spacing independent of increased volume. The data revealed that a two- or three-critical-movement phasing scheme usually resulted in the lowest mean interchange delay and the fewest stops. Overall, the results provide an initial signal timing scheme for practitioners given a crossover spacing, an increased volume, or both. Future work will include exploring low volumes, balanced interchange volumes, and their effects on the four-critical-movement phasing scheme, as well as the effect of closely spaced adjacent intersections. DA - 2017/// PY - 2017/// DO - 10.3141/2620-02 IS - 2620 SP - 10-19 SN - 2169-4052 ER - TY - JOUR TI - Turboroundabouts along corridors analysis of operational and environmental impacts AU - Fernandes, P. AU - Rouphail, N. M. AU - Coelho, M. C. T2 - Transportation Research Record DA - 2017/// PY - 2017/// IS - 2627 SP - 46-56 ER - TY - JOUR TI - Real-World Freeway and Ramp Activity and Emissions for Light-Duty Gasoline Vehicles AU - Frey, H. Christopher AU - Delavarrafiee, Maryam AU - Singh, Sanjam T2 - TRANSPORTATION RESEARCH RECORD AB - There are few data on differences in real-world emissions by in-use vehicles when they operate on freeway ramps compared with operations on the freeway itself. The objective of this paper is to quantify the variability in link-based emissions rates for on-ramps and off-ramps in comparison to rates on freeways. Real-world measurements were made with the use of a portable emissions measurement system (PEMS) for selected vehicles, ramps, and freeway segments. The methodology included development of a study design for field data collection of vehicle activity and emissions, execution of the study design, quality assurance of the raw data, and analysis of the quality-assured data. Four light-duty gasoline vehicles were driven on two routes, each composed of on-ramp, freeway, and off-ramp links. Data were collected for morning peak, evening peak, and off-peak time periods. A PEMS test was used to measure exhaust emissions of oxides of nitrogen (NO x ), hydrocarbon (HC), and carbon monoxide (CO). The emissions rates for on-ramps were shown to be substantially higher than rates on freeways for NO x , HC, and CO. Some of this variability in emissions rates can be explained by link average vehicle specific power, which can vary by time of day and from one location to another. The variability in emissions rates by route and time of day indicates that there can be complex interactions between traffic flow, road geometry, and emissions rates. Recommendations are offered for additional study and regarding how these results can be used by researchers and practitioners. DA - 2017/// PY - 2017/// DO - 10.3141/2627-03 VL - 2627 IS - 2627 SP - 17-25 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85033794699&partnerID=MN8TOARS ER - TY - JOUR TI - On-Road Visual Sign Salience, Driver Attention Allocation, and Target Detection Accuracy AU - Zahabi, Maryam AU - Pankok, Carl, Jr. AU - Kaber, David B. AU - Machado, Patricia AU - Lau, Mei Ying AU - Hummer, Joseph E. AU - Rasdorf, William T2 - TRANSPORTATION RESEARCH RECORD AB - Previous studies have empirically assessed the effect of on-road signage on driver distraction and attention allocation through eye-tracking measures and driving simulations. However, state and federal agencies might be able to make use of simpler approaches to determining the potential visual load of on-road signs. This study compared different on-road signage (food, gas and attraction, and distance guide signs) with respect to visual salience, assessed the effect of the number of panels and logo format on signage salience, and analyzed associations between salience values for different sign types with target detection accuracy and off-road glance duration. Visual salience of signs was measured with the salience using the natural statistics (SUNs) method. For correlation analyses between sign salience, attention allocation, and detection accuracy, a sample of 120 drivers participated in two driving simulation studies. Results revealed food business signs, containing all pictorial logos, to be more salient than gas and attraction and distance guide signs. In addition, results revealed that increasing the number of sign panels from six to nine significantly increased visual salience. It was also found that attraction signs including all pictorial logos were more salient than signs with text-based logos. Results did not reveal statistically significant relationships between visual salience and attention allocation. In addition, there was no significant correlation between target detection accuracy and visual salience for various sign types. Future work with a higher sign-sampling rate is needed to assess whether the SUNs method is a useful measure for determining if roadway sign salience is a driving factor in distraction. DA - 2017/// PY - 2017/// DO - 10.3141/2663-06 IS - 2663 SP - 40-47 SN - 2169-4052 ER - TY - JOUR TI - Lane utilization model development for diverging diamond interchanges AU - Yeom, C. AU - Schroeder, B. J. AU - Cunningham, C. AU - Salamati, K. AU - Rouphail, N. M. T2 - Transportation Research Record DA - 2017/// PY - 2017/// IS - 2618 SP - 27-37 ER - TY - JOUR TI - Evaluation of Small Specimen Geometries for Asphalt Mixture Performance Testing and Pavement Performance Prediction AU - Lee, Kangjin AU - Pape, Sonja AU - Castorena, Cassie AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - The use of small specimen geometries in asphalt mixture performance testing to enable the testing of as-built pavement layers has been gaining attention in recent years. Small specimens could also improve the testing efficiency of laboratory-fabricated specimens by allowing the extraction of multiple test specimens per gyratory-compacted sample. Rigorous assessment of the small specimen geometries is required before the use of such geometries is standardized. In this study, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue. Three specimen geometries (100-mm- and 38-mm-diameter cylindrical specimens and 25- × 50-mm prismatic specimens) were compared by using five mixtures with a nominal maximum aggregate size (NMAS) ranging from 9.5 to 25.0 mm. The results show that the dynamic modulus and phase angle master curves agreed at low and intermediate temperatures, regardless of the NMAS values of the mixture. At the high temperature, the small specimen dynamic modulus values were slightly higher and the phase angle values were slightly lower than those of the large specimens. The specimen-to-specimen variability for the large and small specimens was comparable. The fatigue test results for the mixtures evaluated were comparable, except for the 25-mm mixture, which proved problematic in the testing of both small and large specimens. Pavement performance was predicted by the layered viscoelastic analysis for critical distresses program by using the test results for the small and large specimens. These results suggest that specimen geometry had a minimal effect on pavement fatigue damage predictions, which indicates promise for the use of small specimen geometries in practice. DA - 2017/// PY - 2017/// DO - 10.3141/2631-09 IS - 2631 SP - 74-82 SN - 2169-4052 ER - TY - JOUR TI - Evaluating the US Mid-Century Strategy for Deep Decarbonization amidst early century uncertainty AU - Galik, Christopher S. AU - DeCarolis, Joseph F. AU - Fell, Harrison T2 - CLIMATE POLICY AB - The recent change in US presidential administrations has introduced significant uncertainty about both domestic and international policy support for continued reductions in GHG emissions. This brief analysis estimates the potential climate ramifications of changing US leadership, contrasting the Mid-Century Strategy for Deep Decarbonization (MCS) released under the Obama Administration, with campaign statements, early executive actions, and prevailing market conditions to estimate potential emission pathways under the Trump Administration. The analysis highlights areas where GHG reductions are less robust to changing policy conditions, and offers brief recommendations for addressing emissions in the interim. It specifically finds that continued reductions in the electricity sector are less vulnerable to changes in federal policy than those in the built environment and land use sectors. Given the long-lived nature of investments in these latter two sectors, however, opportunities for near-term climate action by willing cities, states, private landowners, and non-profit organizations warrant renewed attention in this time of climate uncertainty.Key policy insightsThe recent US presidential election has already impacted mitigation goals and practices, injecting considerable uncertainty into domestic and international efforts to address climate change.A strategic assessment issued in the final days of the Obama Administration for how to reach long-term climate mitigation objectives provides a baseline from which to gauge potential changes under the Trump Administration.Though market trends may continue to foster emission declines in the energy sector, emission reductions in the land use sector and the built environment are subject to considerable uncertainty.Regardless of actions to scale back climate mitigation efforts, US emissions are likely to be flat in the coming years. Assuming that emissions remain constant under President Trump and that reductions resume afterwards to meet the Obama Administration mid-century targets in 2050, this near-term pause in reductions yields a difference in total emissions equivalent to 0.3–0.6 years of additional global greenhouse gas emissions, depending on the number of terms served by a Trump Administration. DA - 2017/// PY - 2017/// DO - 10.1080/14693062.2017.1340257 VL - 17 IS - 8 SP - 1046-1056 SN - 1752-7457 KW - climate change mitigation KW - climate change policies KW - energy markets KW - land use KW - land use change and forestry (LULUCF) KW - transportation sector ER - TY - JOUR TI - Closure to "Modified Plastic-Hinge Method for Circular RC Bridge Columns" by Jason C. Goodnight, Mervyn J. Kowalsky, and James M. Nau AU - Goodnight, Jason C. AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - JOURNAL OF STRUCTURAL ENGINEERING DA - 2017/9// PY - 2017/9// DO - 10.1061/(asce)st.1943-541x.0001867 VL - 143 IS - 9 SP - SN - 1943-541X ER - TY - JOUR TI - Characterization of Permanent Deformation of Asphalt Mixtures with Minimum Strain Rate, LVECD Program, and Triaxial Stress Sweep Test AU - Kim, Dahae AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - The rutting resistance of asphalt concrete is typically assessed by using flow number tests in the lab in accordance with AASHTO TP 79. However, the flow number represents the rutting resistance of the material with regard to ranking for only a specific test condition. A significant amount of testing effort is needed to evaluate rutting resistance by using the flow number test under various loading conditions and temperatures. Therefore, researchers have developed alternative test methods to reduce the testing effort. For example, the incremental repeated-load permanent deformation test and the triaxial stress sweep (TSS) test are two promising protocols that can predict the permanent deformation of asphalt mixtures efficiently and accurately. This study compares the minimum strain rates (MSRs) obtained from incremental repeated-load permanent deformation and TSS tests to examine the ability of the TSS test to analyze the MSRs of asphalt mixtures. In addition, the viscoplastic shift model calibrated from the TSS test that is implemented in the layered viscoelastic pavement analysis for critical distresses (LVECD) program was used to predict the rut depths of 16 pavement sections from four sources. The MSRs and rut depths predicted from the LVECD program were compared with actual measured rut depths. The results of this study indicated that the MSR results could only be used to rank the rutting susceptibility of single-layer asphalt pavements. For a multilayered pavement system, structural level analysis is necessary to predict the accurate rutting performance and rut depths of the test sections. DA - 2017/// PY - 2017/// DO - 10.3141/2631-11 IS - 2631 SP - 96-104 SN - 2169-4052 ER - TY - JOUR TI - Application of high-resolution vehicle data for free-flow speed estimation AU - Rouphail, N. M. AU - Kim, S. AU - Aghdashi, S. T2 - Transportation Research Record DA - 2017/// PY - 2017/// IS - 2615 SP - 105-112 ER - TY - JOUR TI - Addressing Raveling Resistance in Chip Seal Specifications AU - Adams, Javon AU - Castorena, Cassie AU - Im, Jeong Hyuk AU - Ilias, Mohammad AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Chip seals are applied to existing roadways to slow deterioration and improve pavement surface conditions without increasing the pavement’s structural capacity. The raveling of chip seals can cause damage to vehicles and thus is a safety concern. Raveling resistance is related to both material application rates and material properties. The current chip seal specifications fail to adequately address the material-related aspects of raveling resistance. This study seeks to develop recommendations to address raveling resistance in future chip seal specifications. Strain sweep binder tests, binder bond strength (BBS) tests, and Vialit chip seal mixture tests were conducted to assess early raveling, late raveling, and wet raveling at two intermediate temperatures. The results demonstrate that the bond that develops between the residual binder and the aggregate is highly dependent on the interaction between the emulsion and the aggregate during curing. The importance of emulsion–aggregate compatibility in raveling resistance indicates that raveling resistance cannot be addressed in binder specifications alone. Rather, it is recommended that intermediate temperature raveling resistance should be addressed during chip seal mixture design. Vialit and BBS tests, in which emulsion is cured on rock, can both be used to effectively quantify the aggregate loss potential of a chip seal. These two tests are able to capture the benefits of polymer modification and produce results that correlate. However, the Vialit tests are easier to implement than the BBS tests and require no expensive equipment. Therefore, Vialit tests are recommended to address early, late, and wet raveling resistance in future chip seal specifications. DA - 2017/// PY - 2017/// DO - 10.3141/2612-05 IS - 2612 SP - 39-46 SN - 2169-4052 ER - TY - JOUR TI - A review of the airborne and waterborne emissions from uncontrolled solid waste disposal sites AU - Levis, James W. AU - Weisbrod, Annie AU - Van Hoof, Gert AU - Barlaz, Morton A. T2 - Critical Reviews in Environmental Science and Technology AB - The objective of this review is to critically analyze literature, data, and models on the environmental releases from the uncontrolled disposal and burning of solid waste. Major concerns include releases of greenhouse gases, particulate matter, and leachate. Many factors influence these releases including waste composition, site depth, and climate. While the impact of these factors is understood qualitatively, there is little data and considerable uncertainty in model predictions. One limitation is that in general, predicted emissions are not responsive to changes in waste composition. Estimating impacts to human health and the environment from the predicted emissions results in additional uncertainty. DA - 2017/6/18/ PY - 2017/6/18/ DO - 10.1080/10643389.2017.1342513 VL - 47 IS - 12 SP - 1003-1041 J2 - Critical Reviews in Environmental Science and Technology LA - en OP - SN - 1064-3389 1547-6537 UR - http://dx.doi.org/10.1080/10643389.2017.1342513 DB - Crossref KW - Environmental impacts KW - open burning KW - open dumps KW - solid waste KW - uncontrolled landfills ER - TY - JOUR TI - Tools for the Wider Economic Impact Assessment of Corridor Improvements: Lessons Learned from the FHWA Implementation Assistance Program in Indiana AU - Chacon-Hurtado, Davis AU - Bardaka, Eleni AU - Yang, Ruiman AU - Gkritza, Konstantina AU - Fricker, Jon D. T2 - JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS AB - In an effort to assist transportation professionals with the evaluation of wider economic benefits (WEB) of highway improvements, this paper provides important insights into the open-source AASHTO EconWorks wider economic benefits analysis tools using three case studies located in Indiana. The paper makes a significant contribution to the state of practice by providing an in-depth discussion of the lessons learned during the Federal Highway Administration (FHWA) implementation assistance program in Indiana. The paper briefly presents the theoretical background related to the development of the tools and explains data needs and sources. The discussion of the case studies primarily focuses on the sensitivity of the tools’ results to critical input parameters (such as volume to capacity ratio and productivity elasticity), which has not been addressed in previous studies. Lastly, the paper elaborates on the applicability and limitations of the tools, and also discusses their potential integration into an agency’s decision-making process. The inferences from this case study can be useful for state departments of transportation (DOTs), metropolitan planning organizations (MPOs), and other organizations interested in quantifying the potential productivity gains associated with planned or future highway projects. DA - 2017/5// PY - 2017/5// DO - 10.1061/jtepbs.0000051 VL - 143 IS - 5 SP - SN - 2473-2893 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85044935751&partnerID=MN8TOARS KW - Accessibility KW - Connectivity KW - Travel time reliability KW - Productivity KW - Middle-stage planning KW - Evaluation ER - TY - JOUR TI - The economics of electricity generation from Gulf Stream currents AU - Li, Binghui AU - Queiroz, Anderson Rodrigo AU - DeCarolis, Joseph F. AU - Bane, John AU - He, Ruoying AU - Keeler, Andrew G. AU - Neary, Vincent S. T2 - ENERGY AB - Hydrokinetic turbines harnessing energy from ocean currents represent a potential low carbon electricity source. This study provides a detailed techno-economic assessment of ocean turbines operating in the Gulf Stream off the North Carolina coast. Using hindcast data from a high-resolution ocean circulation model in conjunction with the US Department of Energy's reference model 4 (RM4) for ocean turbines, we examine resource quality and apply portfolio optimization to identify the best candidate sites for ocean turbine deployment. We find that the lowest average levelized cost of electricity (LCOE) from a single site can reach 400 $/MWh. By optimally selecting geographically dispersed sites and taking advantage of economies of scale, the variations in total energy output can be reduced by an order of magnitude while keeping the LCOE below 300 $/MWh. Power take-off and transmission infrastructure are the largest cost drivers, and variation in resource quality can have a significant influence on the project LCOE. While this study focuses on a limited spatial domain, it provides a framework to assess the techno-economic feasibility of ocean current energy in other western boundary currents. DA - 2017/9/1/ PY - 2017/9/1/ DO - 10.1016/j.energy.2017.06.048 VL - 134 SP - 649-658 SN - 1873-6785 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85020893529&partnerID=MN8TOARS KW - Ocean current energy KW - Gulf Stream KW - Portfolio optimization KW - Energy economics KW - Renewable generation ER - TY - JOUR TI - Synthesis of public water supply use in the United States: Spatio‐temporal patterns and socio‐economic controls AU - Sankarasubramanian, A. AU - Sabo, J. L. AU - Larson, K. L. AU - Seo, S. B. AU - Sinha, T. AU - Bhowmik, R. AU - Vidal, A. Ruhi AU - Kunkel, K. AU - Mahinthakumar, G. AU - Berglund, E. Z. AU - Kominoski, J. T2 - Earth's Future AB - Abstract Recent U.S. Geological Survey water‐use report suggests that increasing water‐use efficiency could mitigate the supply‐and‐demand imbalance arising from changing climate and growing population. However, this rich data have neither analyzed to understand the underlying patterns, nor have been investigated to identify the factors contributing to this increased efficiency. A national‐scale synthesis of public supply withdrawals (“withdrawals”) reveals a strong North–south gradient in public supply water use with the increasing population in the South contributing to increased withdrawal. Contrastingly, a reverse South–north gradient exists in per capita withdrawals (“efficiency”), with northern states consistently improving the efficiency, while the southern states' efficiency declined. Our analyses of spatial patterns of per capita withdrawals further demonstrate that urban counties exhibit improved efficiency over rural counties. Improved efficiency is also demonstrated over high‐income and well‐educated counties. Given the potential implications of the findings in developing long‐term water conservation measures (i.e., increasing block rates), we argue the need for frequent updates, perhaps monthly to annual, of water‐use data for identifying effective strategies that control the water‐use efficiency in various geographic settings under a changing climate. DA - 2017/7// PY - 2017/7// DO - 10.1002/2016ef000511 VL - 5 IS - 7 SP - 771-788 J2 - Earth's Future LA - en OP - SN - 2328-4277 2328-4277 UR - http://dx.doi.org/10.1002/2016EF000511 DB - Crossref ER - TY - JOUR TI - Primary and Photochemically Aged Aerosol Emissions from Biomass Cookstoves: Chemical and Physical Characterization AU - Reece, Stephen M. AU - Sinha, Aditya AU - Grieshop, Andrew P. T2 - Environmental Science & Technology AB - Secondary organic aerosol (SOA) formation during photo-oxidation of primary emissions from cookstoves used in developing countries may make important contributions to their climate and air quality impacts. We present results from laboratory experiments with a field portable oxidation flow reactor (F-OFR) to study the evolution of emissions over hours to weeks of equivalent atmospheric aging. Lab tests, using dry red oak, measured fresh and aged emissions from a 3 stone fire (TSF), a “rocket” natural draft stove (NDS), and a forced draft gasifier stove (FDGS), in order of increasing modified combustion efficiency (MCE) and decreasing particulate matter emission factors (EF). SOA production was observed for all stoves/tests; organic aerosol (OA) enhancement factor ranged from 1.2 to 3.1, decreasing with increased MCE. In primary emissions, OA mass spectral fragments associated with oxygenated species (primary biomass burning markers) increased (decreased) with MCE; fresh OA from FDGS combustion was especially oxygenated. OA oxygenation increased with further oxidation for all stove emissions, even where minimal enhancement was observed. More efficient stoves emit particles with greater net direct specific warming than TSFs, with the difference increasing with aging. Our results show that the properties and evolution of cookstove emissions are a strong function of combustion efficiency and atmospheric aging. DA - 2017/7/25/ PY - 2017/7/25/ DO - 10.1021/acs.est.7b01881 VL - 51 IS - 16 SP - 9379-9390 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.7b01881 DB - Crossref ER - TY - JOUR TI - Impact of natural organic matter and inorganic solutes on energy recovery from five real salinity gradients using reverse electrodialysis AU - Kingsbury, R. S. AU - Liu, F. AU - Zhu, S. AU - Boggs, C. AU - Armstrong, M. D. AU - Call, D. F. AU - Coronell, O. T2 - JOURNAL OF MEMBRANE SCIENCE AB - “Blue energy” technologies such as reverse electrodialysis (RED) have received significant research attention over the last several years as a means of generating clean electricity from natural salinity gradients (e.g., seawater and river water). To date, however, knowledge of RED is largely based on synthetic sodium chloride solutions that simulate natural waters. Accordingly, in this work we measured the RED performance of five real water pairs, including seawater, river water, desalination brine, saline wastewater from a pickling plant, and treated wastewater. We compared the performance of each real water pair with that of synthetic control waters to investigate the individual impacts of inorganic constituents (e.g., multivalent ions) and natural organic matter (NOM). Our results indicate that the presence of NOM has a larger impact on power density than ionic composition. Specifically, NOM reduced power densities by up to 43%, while inorganic constituents reduced power densities by up to 8% compared to control waters. Furthermore, UV-absorbing NOM present in the dilute compartment of the RED stack was strongly associated with reduced membrane permselectivity and energy efficiency. Taken together, our findings highlight the important role of organic matter in determining the RED performance of real waters. DA - 2017/11/1/ PY - 2017/11/1/ DO - 10.1016/j.memsci.2017.07.038 VL - 541 SP - 621-632 SN - 1873-3123 KW - Reverse electrodialysis KW - Salinity gradient energy KW - Ion exchange membranes KW - Natural organic matter KW - Blue energy ER - TY - CONF TI - Experimental investigation of the horizontal resistance of group suction piles with different pile spacing AU - Lee, J. AU - Do, J. N. AB - In this study, a new type of suction pile foundation for floating structures, namely group suction piles, was proposed to improve the shortcomings of conventional single suction piles. Small-scale model tests were performed to estimate the horizontal behavior of single suction piles and group suction piles with different pile spacing (2, 3 and 4 times the pile diameter) under various loading conditions in terms of loading locations and inclinations. The horizontal behavior of group suction piles with different pile spacing was analyzed for various loading locations and load inclinations based on the model tests. For the given group pile configurations (a group pile having 9 component piles with a pile formation of 3 × 3), the horizontal resistance increased with increasing pile spacing. The maximum ultimate horizontal resistances were found at the loading locations of 50% of the embedded depth. Unlikely in the single suction pile case, the significantly maintained residual resistances were found for group suction piles. The residual resistances of group suction piles were at least higher than 40% of the corresponding ultimate horizontal resistances. C2 - 2017/// C3 - Geotechnical frontiers 2017: foundations DA - 2017/// DO - 10.1061/9780784480465.016 SP - 154-163 M1 - 279 ER - TY - JOUR TI - Capacitive Neutralization Dialysis for Direct Energy Generation AU - Liu, Yue AU - Zhang, Yi AU - Ou-Yang, Wei AU - Sales, Bruno Bastos AU - Sun, Zhuo AU - Liu, Fei AU - Zhao, Ran T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Capacitive neutralization dialysis energy (CNDE) is proposed as a novel energy-harvesting technique that is able to utilize waste acid and alkaline solutions to produce electrical energy. CNDE is a modification based on neutralization dialysis. It was found that a higher NaCl concentration led to a higher open-circuit potential when the concentrations of acid and alkaline solutions were fixed. Upon closing of the circuit, the membrane potential was used as a driving force to move counter ions into the electrical double layers at the electrode–liquid interface, thereby creating an ionic current. Correspondingly, in the external circuit, electrons flow through an external resistor from one electrode to the other, thereby generating electrical energy directly. The influence of external resistances was studied to achieve greater energy extraction, with the maximum output of 110 mW/m2 obtained by employing an external resistance of 5 Ω together with the AC-coated electrode. DA - 2017/8/15/ PY - 2017/8/15/ DO - 10.1021/acs.est.7b01426 VL - 51 IS - 16 SP - 9363-9370 SN - 1520-5851 ER - TY - JOUR TI - A phase-field formulation for fracture in ductile materials: Finite deformation balance law derivation, plastic degradation, and stress triaxiality effects (vol 312, pg 130, 2016) AU - Borden, Michael J. AU - Hughes, Thomas J. R. AU - Landis, Chad M. AU - Anvari, Amin AU - Lee, Isaac J. T2 - COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING DA - 2017/9/1/ PY - 2017/9/1/ DO - 10.1016/j.cma.2017.06.023 VL - 324 SP - 712-713 SN - 1879-2138 ER - TY - JOUR TI - A new method to account for seasonal peak traffic volumes in project prioritization AU - Yeom, C. AU - Searcy, S.E. AU - Findley, D.J. AU - Schroeder, B.J. T2 - ITE Journal (Institute of Transportation Engineers) DA - 2017/// PY - 2017/// VL - 87 IS - 8 SP - 37-43 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85044237554&partnerID=MN8TOARS ER - TY - JOUR TI - Use of Fine Aggregate Matrix Experimental Data in Improving Reliability of Fatigue Life Prediction of Asphalt Concrete: Sensitivity of This Approach to Variation in Input Parameters AU - Gudipudi, Padmini P. AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - Asphalt concrete (AC) material performance has been assessed by numerous mechanistic models over the years. Often these models are purported to enable more accurate prediction of the pavement service life than existing empirical models. Most of these models use fundamental material properties, which are obtained by performing experiments on the materials, as input variables. However, by introducing more variables, these models create the potential for greater uncertainty because the variables have inherent variability. Variations observed in these input parameters affect the reliability of any resulting performance predictions. In an effort to improve the reliability of fatigue life predictions, experimental data from the fine aggregate matrix (FAM) phase was used in this study for predicting fatigue life. From the comparative assessment, it was observed that the reliability of fatigue life predictions was improved by more than 50% when data from the FAM phase rather than AC data were used. An upscaling procedure was used in predicting the AC material fundamental properties and then in performing a reliability analysis with the predicted data. More reliable fatigue prediction results were also observed when the AC predicted data were used; however, this improvement was not as good as that in the FAM phase. A parametric sensitivity analysis was performed to determine whether variation in any one parameter resulted in a greater impact on the resultant reliability than did variation of other parameters. From the analysis, it was observed that the variation of the modulus parameter affected the reliability predictions more than did the variation of the other input parameters considered in this study, regardless of the model failure criteria used. DA - 2017/1// PY - 2017/1// DO - 10.3141/2631-07 VL - 2631 IS - 1 SP - 65-73 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2631-07 DB - Crossref ER - TY - JOUR TI - Micromechanical shear modulus modeling of activated crumb rubber modified asphalt cements AU - Medina, J. AU - Underwood, B.S. AU - Kaloush, K.E. T2 - Construction and Building Materials DA - 2017/// PY - 2017/// SP - 56-65 ER - TY - CONF TI - Maintaining reliability of transportation systems and interdependent infrastructure under climate change AU - Markolf, S. AU - Hoehne, C. AU - Fraser, A. AU - Underwood, B.S. AU - Chester, M. C2 - 2017/// C3 - International Society of Industrial Ecology and International Symposium on Sustainable Systems and Technology Conference DA - 2017/// ER - TY - CONF TI - Life-cycle modeling of municipal solid waste landfills AU - Levis, J. W. AU - Barlaz, Morton AB - Landfills that receive municipal solid waste represent a critical component of solid waste infrastructure in the U.S. and are a leading source of greenhouse gas emissions. Thus, it is critical to understand the factors that control the environmental performance of landfills. Life-cycle modeling of landfills is complex, as landfills constantly change over time. The objective of this research was to develop a life-cycle model of an average ton of municipal solid waste disposed in a “national average” landfill. The framework considers critical factors relating to the temporal changes in landfill gas generation, collection, beneficial use, and oxidation. The model calculates temporally averaged landfill gas collection efficiencies for individual waste components in consideration of the aforementioned factors. The results indicate that for mixed waste, 12 to 41% of the generated methane becomes fugitive emissions. The results also show the significant potential benefits of earlier landfill gas collection. C2 - 2017/// C3 - Geotechnical frontiers 2017: waste containment, barriers, remediation, and sustainable geoengineering DA - 2017/// DO - 10.1061/9780784480434.038 SP - 355–368 M1 - 276 ER - TY - JOUR TI - Large-area nanolattice film with enhanced modulus, hardness, and energy dissipation AU - Bagal, A. AU - Zhang, X. A. AU - Shahrin, R. AU - Dandley, E. C. AU - Zhao, J. J. AU - Poblete, F. R. AU - Oldham, C. J. AU - Zhu, Y. AU - Parsons, G. N. AU - Bobko, C. AU - Chang, C. H. T2 - Scientific Reports DA - 2017/// PY - 2017/// VL - 7 ER - TY - JOUR TI - Investigation of proper long-term laboratory aging temperature for performance testing of asphalt concrete AU - Rad, Farhad Yousefi AU - Elwardany, Michael D. AU - Castorena, Cassie AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The performance implications of laboratory asphalt loose mixture aging at 135 °C were evaluated by comparing the performance of mixtures subjected to long-term aging at 95 °C and 135 °C to yield the same rheology. Although the rheology of the mixtures aged at 135 °C and 95 °C matched, their chemistry differed. Performance test results suggest that the chemical changes induced by aging at 135 °C can negatively impact performance. The relationship between binder chemistry and rheology was unaffected by aging temperatures at or below 95 °C. The rate of oxidation increased with an increase in temperature, and thus, the optimal loose mixture aging temperature is 95 °C. DA - 2017/8/30/ PY - 2017/8/30/ DO - 10.1016/j.conbuildmat.2017.04.197 VL - 147 SP - 616-629 SN - 1879-0526 KW - Asphalt pavement KW - Performance KW - Long-term aging KW - Aging temperature ER - TY - CONF TI - Improvement in reliability of fatigue life prediction of asphalt concrete using fine aggregate matrix (FAM) experimental data and its sensitivity to input parameters AU - Gudipudi, P. AU - Underwood, B.S. C2 - 2017/// C3 - 96th Annual Meeting of the Transportation Research Board DA - 2017/// ER - TY - CONF TI - Implications of autonomous truck use on flexible pavement performance and design AU - Noorvand, H. AU - Sai, G. AU - Underwood, B.S. C2 - 2017/// C3 - 96th Annual Meeting of the Transportation Research Board DA - 2017/// ER - TY - CONF TI - Impact of climate change on the pavement performance and its sensitivity to various climate prediction models AU - Gudipudi, P. AU - Underwood, B.S. AU - Zalghout, A. C2 - 2017/// C3 - 96th Annual Meeting of the Transportation Research Board DA - 2017/// ER - TY - CONF TI - Impact of alternative project deliver systems on the International Roughness Index (IRI) ? Case studies of transportation projects in the Western U.S. AU - Abkarian, H. AU - Asmar, M. AU - Underwood, B.S. C2 - 2017/// C3 - 96th Annual Meeting of the Transportation Research Board DA - 2017/// ER - TY - JOUR TI - Evaluation of the sensitivity of asphalt concrete modulus to binder oxidation with a multiple length scale study AU - Gundla, Akshay AU - Gudipudi, Padmini AU - Underwood, B. Shane T2 - Construction and Building Materials AB - Abstract It is well known that the properties of asphalt concrete mixture are affected by the oxidation of asphalt cement. However, the precise relationship between these two length scales remains largely uncharacterized. In the present study, a multiple length scale evaluation approach is applied to study and quantify the sensitivity of the mechanical properties of asphalt concrete mixture to asphalt cement oxidation. The study involves temperature and frequency sweep experiments on unaged and aged asphalt cement (to establish baseline properties), asphalt mastic (to consider physico-chemical aspects), and Fine Aggregate Matrix (FAM – to consider air voids and aggregate interaction effects). The multiscale approach separates effects of aggregate-binder physico-chemical interactions from those caused by air voids and physical aggregate interactions. Also, all asphalt cements were pre-aged to specific aging levels before preparing respective aged mastics or FAM samples. The methodology adopted for assessment of sensitivity was based on the theory of crossover modulus and second order rate kinetics of asphalt binder oxidation. The results from the analysis indicate that the mechanical properties of mastics are more sensitive to binder oxidation than FAM. Also, mechanical properties of mastics and FAM materials prepared with softer binders are more sensitive to oxidation than those with higher modulus asphalt cements. Finally, it is found that if a laboratory aging procedure is found to match the rheological properties of in-service level of asphalt oxidation at a given level of accuracy, then the expected accuracy in matching the resulting modulus of an asphalt mixture tested after being subjected to that laboratory process will be 1.5–3.6 times higher. DA - 2017/10// PY - 2017/10// DO - 10.1016/j.conbuildmat.2017.07.067 VL - 152 SP - 954-963 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/j.conbuildmat.2017.07.067 DB - Crossref KW - Asphalt binder KW - Mastics KW - FAM KW - Physico-chemical KW - Multiscale KW - Oxidation KW - Sensitivity ER - TY - JOUR TI - Evaluation of in situ RAP binder interaction in asphalt mastics using micromechanical models AU - Gundla, Akshay AU - Underwood, Shane T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - In this article the mastic level structure of asphalt concrete containing reclaimed asphalt pavement (RAP) materials is investigated using the principles of micromechanics. Locally sourced RAP material was screened and sieved to separate the coated fines (smaller than 0.075 mm) from the remaining sizes. These binder coated fines were mixed with virgin filler at proportions commensurate with 0, 10, 30, 50 and 100% RAP dosage levels. Asphalt mastics were prepared with these blended fillers and a PG 64-22 binder at a filler content of 27% by volume. Temperature–frequency sweeps were conducted on the resulting composites as well as the constituents, virgin binder, solvent extracted RAP binder. The results from the experiments showed an expected increase in stiffness with increase in dosage levels. These results were also used to model the hypothesised structure of the composite. The study presented discusses the applicability of Herve and Zaoui model to predict the blended mastic composite and to quantify the amount of blending between RAP binder and newly added asphalt binder. It is found that as the RAP dosage level increases the amount of blending that occurs, as a proportion of the total RAP binder decreases. DA - 2017/// PY - 2017/// DO - 10.1080/10298436.2015.1066003 VL - 18 IS - 9 SP - 798-810 SN - 1477-268X KW - Asphalt mastic KW - reclaimed asphalt pavement KW - micromechanics KW - blending KW - composite ER - TY - JOUR TI - Ensemble modeling informs hypoxia management in the northern Gulf of Mexico AU - Scavia, Donald AU - Bertani, Isabella AU - Obenour, Daniel R. AU - Turner, R. Eugene AU - Forrest, David R. AU - Katin, Alexey T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - A large region of low-dissolved-oxygen bottom waters (hypoxia) forms nearly every summer in the northern Gulf of Mexico because of nutrient inputs from the Mississippi River Basin and water column stratification. Policymakers developed goals to reduce the area of hypoxic extent because of its ecological, economic, and commercial fisheries impacts. However, the goals remain elusive after 30 y of research and monitoring and 15 y of goal-setting and assessment because there has been little change in river nitrogen concentrations. An intergovernmental Task Force recently extended to 2035 the deadline for achieving the goal of a 5,000-km2 5-y average hypoxic zone and set an interim load target of a 20% reduction of the spring nitrogen loading from the Mississippi River by 2025 as part of their adaptive management process. The Task Force has asked modelers to reassess the loading reduction required to achieve the 2035 goal and to determine the effect of the 20% interim load reduction. Here, we address both questions using a probabilistic ensemble of four substantially different hypoxia models. Our results indicate that, under typical weather conditions, a 59% reduction in Mississippi River nitrogen load is required to reduce hypoxic area to 5,000 km2 The interim goal of a 20% load reduction is expected to produce an 18% reduction in hypoxic area over the long term. However, due to substantial interannual variability, a 25% load reduction is required before there is 95% certainty of observing any hypoxic area reduction between consecutive 5-y assessment periods. DA - 2017/8/15/ PY - 2017/8/15/ DO - 10.1073/pnas.1705293114 VL - 114 IS - 33 SP - 8823-8828 SN - 0027-8424 KW - ensemble modeling KW - hypoxia KW - Gulf of Mexico KW - nitrogen-loading targets ER - TY - JOUR TI - Development of modulus and fatigue test protocol for fine aggregate matrix for axial direction of loading AU - Gudipudi, P. AU - Underwood, B.S. T2 - Journal of Testing and Evaluation DA - 2017/// PY - 2017/// VL - 45 IS - 2 SP - 497-508 ER - TY - JOUR TI - Correlating field performance to laboratory dynamic modulus from indirect tension and torsion bar AU - Yang, Shu AU - Braham, Andrew AU - Underwood, Shane AU - Hanz, Andrew AU - Reinke, Gerald T2 - ROAD MATERIALS AND PAVEMENT DESIGN AB - Dynamic modulus has several useful functions in flexible pavements, including stress/strain characterisation, rutting and cracking characterisation, an input into several analytical and numerical models, and a primary input into Pavement ME Design. While the traditional dynamic modulus test is run in the uniaxial configuration, this is not possible for field cores. Therefore, the indirect tension dynamic modulus (IDT |E*|) and torsion bar shear modulus (torsion bar |G*|) have been developed. However, there has been limited research looking at analysing the data from field cores for these two geometries, comparing modulus data from the two geometries, examining in-service ageing of dynamic modulus, and quantifying pavement conditions using dynamic modulus. This research examines 10 field sections in Arkansas, comprising of 4 “good” performing sections, 2 “medium” performing sections, and 4 “poor” performing sections in an attempt to address these four questions. First, this research found that using AASHTO T342 and AASHTO R62 can lead to irrational coefficients but provide rational results. Second, while the IDT |E*| and torsion bar |G*| values were similar at high modulus values, the IDT |E*| values began to increase as the modulus decreased compared to the torsion bar |G*| values, increasing to over a decade of difference. Third, a noticeable difference was observed between the modulus values of the bottom surface layer and top surface layer, with the bottom surface layer showing higher modulus values in all cases. While the upper surface layer showed higher oxidation, other weathering effects such as moisture and traffic appear to have overwhelmed the oxidation effect and pavement deterioration has reduced the integrity of the mix. Finally, both the IDT |E*| and torsion bar |G*| were not able to quantify a noticeable difference between poor and medium performing sections, and medium and good performing sections, but were able to quantify a difference between the poor and good behaving sections. Overall, the IDT |E*| and torsion bar |G*| tests were able to produce consistent master curves, correlate to each other, identify differences between surface course lifts, and quantify differences in field performance. DA - 2017/// PY - 2017/// DO - 10.1080/14680629.2016.1267438 VL - 18 SP - 104-127 SN - 2164-7402 KW - dynamic modulus KW - field performance KW - IDT vertical bar E*vertical bar KW - torsion bar vertical bar G*vertical bar KW - ageing ER - TY - JOUR TI - Construction and Setup of a Bench-scale Algal Photosynthetic Bioreactor with Temperature, Light, and pH Monitoring for Kinetic Growth Tests AU - Karam, Amanda L. AU - McMillan, Catherine C. AU - Lai, Yi-Chun AU - de los Reyes, Francis L., III AU - Sederoff, Heike W. AU - Grunden, Amy M. AU - Ranjithan, Ranji S. AU - Levis, James W. AU - Ducoste, Joel J. T2 - Journal of Visualized Experiments AB - The optimal design and operation of photosynthetic bioreactors (PBRs) for microalgal cultivation is essential for improving the environmental and economic performance of microalgae-based biofuel production. Models that estimate microalgal growth under different conditions can help to optimize PBR design and operation. To be effective, the growth parameters used in these models must be accurately determined. Algal growth experiments are often constrained by the dynamic nature of the culture environment, and control systems are needed to accurately determine the kinetic parameters. The first step in setting up a controlled batch experiment is live data acquisition and monitoring. This protocol outlines a process for the assembly and operation of a bench-scale photosynthetic bioreactor that can be used to conduct microalgal growth experiments. This protocol describes how to size and assemble a flat-plate, bench-scale PBR from acrylic. It also details how to configure a PBR with continuous pH, light, and temperature monitoring using a data acquisition and control unit, analog sensors, and open-source data acquisition software. DA - 2017/6/14/ PY - 2017/6/14/ DO - 10.3791/55545 VL - 6 IS - 124 J2 - JoVE LA - en OP - SN - 1940-087X UR - http://dx.doi.org/10.3791/55545 DB - Crossref KW - Bioengineering KW - Issue 124 KW - Photosynthetic bioreactors KW - microalgae KW - growth kinetics KW - biofuel KW - temperature KW - light KW - pH KW - automated monitoring ER - TY - JOUR TI - Autonomous vehicles: Assessment of the implications of truck positioning on flexible pavement performance and design AU - Noorvand, H. AU - Sai, G. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2017/// PY - 2017/// SP - 21-28 ER - TY - JOUR TI - Assessing the impact of closely-spaced intersections on traffic operations and pollutant emissions on a corridor level AU - Fernandes, P. AU - Coelho, M. C. AU - Rouphail, N. M. T2 - TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT AB - Traffic lights or roundabouts along corridors are usually installed to address location-specific operational needs. An understanding of the impacts on traffic regarding to highly-congested closely-spaced intersections has not been fully addressed. Accordingly, consideration should be given to how these specific segments affect corridor performance as a whole. One mixed roundabout/traffic light/stop-controlled junctions corridor was evaluated with the microscopic traffic model (VISSIM) and emissions methodology (Vehicle Specific Power – VSP). The analysis was focused on two major intersections of the corridor, a roundabout and a traffic light spaced lower than 170 m apart under different traffic demand levels. The traffic data and corridor geometry were coded into VISSIM and compared with an alternative scenario where the traffic light was replaced by a single-lane roundabout. This research also tested a method to improve corridor performance and emissions by examining the integrated effect of the spacing between these intersections on traffic delay and vehicular emissions (carbon dioxide, monoxide carbon, nitrogen oxides, and hydrocarbons). The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used to find the optimal spacing for these intersections. The analysis showed that the roundabout could achieve lower queue length (∼64%) and emissions (16–27%, depending on the pollutant) than the traffic light. The results also suggested that 200 m of spacing using the best traffic control would provide a moderate advantage in traffic operations and emissions as compared with the existing spacing. DA - 2017/7// PY - 2017/7// DO - 10.1016/j.trd.2017.05.016 VL - 54 SP - 304-320 SN - 1879-2340 KW - Intersections KW - Multi-objective optimization KW - Micro-scale modeling KW - Spacing ER - TY - CONF TI - Alternate interpretation of stress sensitivity in AASHTO T350 AU - Stempihar, J. AU - Gundla, A. AU - Underwood, B.S. C2 - 2017/// C3 - 96th Annual Meeting of the Transportation Research Board DA - 2017/// ER - TY - CONF TI - A Model to Describe Heat Generation and Accumulation at Municipal Solid Waste Landfills AU - Hao, Zisu AU - Sun, Mei AU - Ducoste, Joel AU - Barlaz, Morton T2 - Geotechnical Frontiers 2017 AB - There have been reports of landfills in North America that are experiencing elevated temperatures that are resulting in challenging issues for landfill management. The objective of this study is to develop a box model to describe the generation, consumption and release of heat in landfills and subsequently to predict temperature profiles. Initially, a box model was developed that treats the landfill as a completely mixed system in which all relevant reactions are described. This model will make it possible to identify processes and reactions that are most significant. The model is based on thermodynamic principles and accounts for all significant heat sources and sinks in landfills. Heat sources include energy from biotic and abiotic reactions and condensation. Heat removal processes include convection of methane and carbon dioxide, infiltration, leachate collection and evaporation. The model was used to evaluate the heat generation performance of aerobic and anaerobic biodegradation of waste with and without the presence of ash (from coal or municipal solid waste). The model analysis showed that the hydration of ash can increase landfill temperature above that predicted for the disposal of municipal solid waste alone. C2 - 2017/3/30/ C3 - Geotechnical Frontiers 2017 CY - Orlando, FL DA - 2017/3/30/ PY - 2017/3/12/ DO - 10.1061/9780784480434.030 SP - 281–288 M1 - 276 PB - American Society of Civil Engineers SN - 9780784480434 UR - http://dx.doi.org/10.1061/9780784480434.030 ER - TY - JOUR TI - Wind power feasibility analysis under uncertainty in the Brazilian electricity market AU - Aquila, Giancarlo AU - Rotela Junior, Paulo AU - Pamplona, Edson de Oliveira AU - Queiroz, Anderson Rodrigo T2 - ENERGY ECONOMICS AB - Investors must be able to plan and analyze their investments in order to optimize decisions and turn them into profits associated with a particular project. Since electricity producers in the Brazilian electric power system are exposed to a short-term market, the goal of this paper is to propose a framework for investment analysis capable of encompassing different uncertainties and possibilities for wind power generators in a regulated market, characterized by auctions. In order to reach the proposed objective we employ a simulation technique which allows modeling cash flows considering uncertainties in variables related to project financial premises, electricity generation and producer exposure to the short-term market. For such goal, this study presents a new approach for investment analysis that allows the identification of the main uncertainty parameters and risks associated to this class of projects in the Brazilian electricity market. We also employ the Value at Risk technique to perform a risk management analysis in such context. DA - 2017/6// PY - 2017/6// DO - 10.1016/j.eneco.2017.04.027 VL - 65 SP - 127-136 SN - 1873-6181 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85019185087&partnerID=MN8TOARS KW - Wind power KW - Stochastic power generation KW - Electricity markets KW - NPV KW - Renewable energy ER - TY - JOUR TI - Using an AHP-ISM Based Method to Study the Vulnerability Factors of Urban Rail Transit System AU - Song, Liangliang AU - Li, Qiming AU - List, George F. AU - Deng, Yongliang AU - Lu, Ping T2 - SUSTAINABILITY AB - As a sustainable means of public transportation, urban rail transit system undergoes rapid expansion in China. How to provide a safe and reliable service has been the subject of growing attention in this context. However, such work is challenging because rail transit systems are quite vulnerable and influenced by a set of interacting factors. Studying these vulnerability factors will contribute significantly to the operation of rail transit system. From this perspective, this paper made an exploration of the vulnerability factors based on an integrated method consisting of AHP (Analytical Hierarchy Process) and ISM (Interpretative Structural Modeling). Based on literature review, 21 vulnerability factors were identified. Subsequently, expert elicitation was employed to ascertain the importance of each factor and the interrelations among them. The results suggest that management and individual factors have the highest importance weights and the interrelations among vulnerability factors could be expressed as a five-layer structure, in which management factors were inclined to be at the lower level. The research provides valuable information for decision makers to take proactive strategies and reinforcement policies to guarantee safety operation of urban rail transit system and ensure urban public safety, which could promote the sustainable development of cities. DA - 2017/6// PY - 2017/6// DO - 10.3390/su9061065 VL - 9 IS - 6 SP - SN - 2071-1050 KW - urban rail transit KW - vulnerability factor KW - expert elicitation KW - analytical hierarchy process KW - interpretative structural modeling ER - TY - JOUR TI - Time and cost characterisation of emissions from non-road diesel equipment for infrastructure projects AU - Arocho, Ingrid AU - Rasdorf, William AU - Hummer, Joseph AU - Lewis, Phil T2 - INTERNATIONAL JOURNAL OF SUSTAINABLE ENGINEERING AB - The construction process contributes to pollutant emissions, particularly through the operation of diesel- and gasoline-powered equipment. In the past decade, a series of investigations were undertaken to quantify these emissions for a variety of non-road construction equipment performing different activities and undergoing different duty cycles, and a model to estimate quantities of six types of pollutant was developed. This paper uses that model to estimate emissions for four street and utility construction projects which no one has done previously. We combined information from company records with standard construction industry manuals to estimate total emissions for the projects and to examine the pollution patterns and magnitudes. The street construction projects all had similar emission profiles with a large peak at the beginning and a steady output of emissions throughout the duration of the project. For example, in two of the projects studied, half of all CO2 emissions were produced before the projects were 40% completed. Results showed that demolition and earthwork are the activities with the largest contribution. The equipment types with the largest contribution are backhoes, front-end loaders, bulldozers and trenchers. Trenchers, for example, produced 30% of all emissions on the projects on which they were used. DA - 2017/// PY - 2017/// DO - 10.1080/19397038.2016.1218569 VL - 10 IS - 2 SP - 123-134 SN - 1939-7046 KW - Construction equipment KW - air pollutants KW - emissions KW - transportation construction projects KW - construction emissions KW - emissions forecasting KW - construction activities ER - TY - JOUR TI - Optimum location of geogrid reinforcement in unpaved road AU - Mousavi, S. Hamed AU - Gabr, Mohammed A. AU - Borden, Roy H. T2 - Canadian Geotechnical Journal AB - This study evaluated the optimum location of a reinforcement layer to maximize the efficiency of the reinforcement inclusion in an unpaved road section. The analyses are used to investigate the optimum location of the reinforcement layer within the aggregate base course (ABC) layer, and provide a possible reason for the improvement in performance. A series of three-dimensional finite element method analyses was performed, and the strain and stress response of a reinforced unpaved road section with two different ABC thicknesses was evaluated. The analyses were conducted under cyclic loading with three different radii of the circular loaded area. The embedded depth of reinforcement was varied within the ABC layer. Results indicate that regardless of ABC layer thickness, the surface deformation is minimized when the reinforcement is embedded at a depth equal to half of the radius of the loaded area (D = 0.5r). A higher tension force is mobilized in the reinforcement element when it is placed at D = 0.5r. It is also shown that the required thickness of ABC is reduced when the reinforcement layer is implemented at the depth at which the maximum vertical strain occurs. Depending on the thickness of the ABC layer, the finite element analysis results indicate that the reinforcement layer could be ineffectual if it is placed at the interface between the ABC and the subgrade layer as is traditionally the case. DA - 2017/7// PY - 2017/7// DO - 10.1139/cgj-2016-0562 VL - 54 IS - 7 SP - 1047-1054 J2 - Can. Geotech. J. LA - en OP - SN - 0008-3674 1208-6010 UR - http://dx.doi.org/10.1139/cgj-2016-0562 DB - Crossref KW - reinforcement KW - geosynthetics KW - unpaved KW - location KW - finite element ER - TY - CONF TI - Optimization framework to identify demand reduction strategies for shared groundwater resources AU - Al-Amin, S. AU - Berglund, E. Z. AB - Groundwater management strategies should be designed to ensure efficient and sustainable management of groundwater. Optimization models and algorithms can be applied to identify groundwater withdrawals that will satisfy both hydrologic goals and water demands. In groundwater basins where urbanization increases demand and places stress on the supply-demand balance, safe yield based demand restrictions are used to reduce demands. Due to restrictions for water consumers, safe yield-based demand management strategies may result in unintended consequences, such as welfare loss, which is represented as a measure of consumer willingness to pay to avoid water service interruptions. This paper couples an agent-based modeling (ABM) framework and a groundwater model to quantify the improvement in water resources and corresponding welfare losses through mandatory restriction programs and to optimize the permitted yield for applying restrictions. The framework is applied to identify permitted yield as a trigger that should be used to implement restrictions under climate and population uncertainties for a long term planning period for cities in a shared groundwater basin in the Verde River Basin, Arizona. Results indicate trade-offs between groundwater table improvements and welfare losses for changing safe yields. The framework provides a comparison of hydrologic and economic consequences of mandatory restrictions for and reactive management with varying supply-demand balances. The research will guide water restriction policies and improve understanding of the hydrologic and economic consequences of water restriction policies at a basin scale. C2 - 2017/// C3 - World Environmental and Water Resources Congress 2017: Watershed Management, Irrigation and Drainage, and Water Resources Planning and Management DA - 2017/// DO - 10.1061/9780784480601.056 SP - 669-676 ER - TY - JOUR TI - Multivariate Downscaling Approach Preserving Cross Correlations across Climate Variables for Projecting Hydrologic Fluxes AU - Bhowmik, Rajarshi Das AU - Sankarasubramanian, A. AU - Sinha, Tushar AU - Patskoski, Jason AU - Mahinthakumar, G. AU - Kunkel, Kenneth E. T2 - Journal of Hydrometeorology AB - Abstract Most of the currently employed procedures for bias correction and statistical downscaling primarily consider a univariate approach by developing a statistical relationship between large-scale precipitation/temperature with the local-scale precipitation/temperature, ignoring the interdependency between the two variables. In this study, a multivariate approach, asynchronous canonical correlation analysis (ACCA), is proposed and applied to global climate model (GCM) historic simulations and hindcasts from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to downscale monthly precipitation and temperature over the conterminous United States. ACCA is first applied to the CNRM-CM5 GCM historical simulations for the period 1950–99 and compared with the bias-corrected dataset based on quantile mapping from the Bureau of Reclamation. ACCA is also applied to CNRM-CM5 hindcasts and compared with univariate asynchronous regression (ASR), which applies regular regression to sorted GCM and observed variables. ACCA performs better than ASR and quantile mapping in preserving the cross correlation at grid points where the observed cross correlations are significant while reducing fractional biases in mean and standard deviation. Results also show that preservation of cross correlation increases the bias in standard deviation slightly, but estimates observed precipitation and temperature with increased likelihood, particularly for months exhibiting significant cross correlation. ACCA also better estimates the joint likelihood of observed precipitation and temperature under hindcasts since hindcasts estimate the observed variability in precipitation better. Implications of preserving cross correlations across climate variables for projecting runoff and other land surface fluxes are also discussed. DA - 2017/8// PY - 2017/8// DO - 10.1175/jhm-d-16-0160.1 VL - 18 IS - 8 SP - 2187-2205 J2 - J. Hydrometeor. LA - en OP - SN - 1525-755X 1525-7541 UR - http://dx.doi.org/10.1175/JHM-D-16-0160.1 DB - Crossref ER - TY - JOUR TI - Impact of alternative project deliver systems on the International Roughness Index (IRI) ? case studies of transportation projects in the Western U.S. AU - Abkarian, H. AU - Asmar, M. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2017/// PY - 2017/// VL - 2630 SP - 76-84 ER - TY - JOUR TI - Arterial waveguide model for shear wave elastography: implementation and in vitro validation AU - Astaneh, Ali Vaziri AU - Urban, Matthew W. AU - Aquino, Wilkins AU - Greenleaf, James F. AU - Guddati, Murthy N. T2 - PHYSICS IN MEDICINE AND BIOLOGY AB - Arterial stiffness is found to be an early indicator of many cardiovascular diseases. Among various techniques, shear wave elastography has emerged as a promising tool for estimating local arterial stiffness through the observed dispersion of guided waves. In this paper, we develop efficient models for the computational simulation of guided wave dispersion in arterial walls. The models are capable of considering fluid-loaded tubes, immersed in fluid or embedded in a solid, which are encountered in in vitro/ex vivo, and in vivo experiments. The proposed methods are based on judiciously combining Fourier transformation and finite element discretization, leading to a significant reduction in computational cost while fully capturing complex 3D wave propagation. The developed methods are implemented in open-source code, and verified by comparing them with significantly more expensive, fully 3D finite element models. We also validate the models using the shear wave elastography of tissue-mimicking phantoms. The computational efficiency of the developed methods indicates the possibility of being able to estimate arterial stiffness in real time, which would be beneficial in clinical settings. DA - 2017/7/7/ PY - 2017/7/7/ DO - 10.1088/1361-6560/aa6ee3 VL - 62 IS - 13 SP - 5473-5494 SN - 1361-6560 KW - arterial stiffness KW - guided waves KW - finite element KW - viscoelasticity KW - fluid-structure interaction ER - TY - JOUR TI - Adaptive subdomain modeling: A multi-analysis technique for ocean circulation models AU - Altuntas, Alper AU - Baugh, John T2 - OCEAN MODELLING AB - Many coastal and ocean processes of interest operate over large temporal and geographical scales and require a substantial amount of computational resources, particularly when engineering design and failure scenarios are also considered. This study presents an adaptive multi-analysis technique that improves the efficiency of these computations when multiple alternatives are being simulated. The technique, called adaptive subdomain modeling, concurrently analyzes any number of child domains, with each instance corresponding to a unique design or failure scenario, in addition to a full-scale parent domain providing the boundary conditions for its children. To contain the altered hydrodynamics originating from the modifications, the spatial extent of each child domain is adaptively adjusted during runtime depending on the response of the model. The technique is incorporated in ADCIRC++, a re-implementation of the popular ADCIRC ocean circulation model with an updated software architecture designed to facilitate this adaptive behavior and to utilize concurrent executions of multiple domains. The results of our case studies confirm that the method substantially reduces computational effort while maintaining accuracy. DA - 2017/7// PY - 2017/7// DO - 10.1016/j.ocemod.2017.05.009 VL - 115 SP - 86-104 SN - 1463-5011 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85020014888&partnerID=MN8TOARS KW - Storm surge KW - Adaptive algorithm KW - Subdomain modeling KW - Moving boundaries KW - ADCIRC ER - TY - JOUR TI - Trash removal methods for improved mechanical emptying of pit latrines using a screw auger AU - Sisco, Tracey AU - Rogers, Tate AU - Beckwith, Walt AU - Chipeta, Willy AU - Holm, Rochelle AU - Buckley, Christopher A. AU - de los Reyes, Francis L., III T2 - Journal of Water Sanitation and Hygiene for Development AB - Trash in pit latrines is one of the largest challenges facing pit emptying technologies, including the powered auger (the Excrevator), developed for improved emptying in lower- and lower-middle income countries. This study focused on two trash removal methods in conjunction with pit emptying by the Excrevator: (1) simultaneous removal of trash with sludge and (2) manual trash removal prior to sludge removal. Simultaneous removal was tested by adding to the inlet of the Excrevator system two cutting heads designed to reduce the size of trash particles before entering the pipe and auger. Laboratory testing indicated that the auger will not provide the rotational speeds necessary for proper maceration of fibrous materials such as clothing, indicating that a separate maceration unit with higher rotational methods may be more appropriate. Four manual trash removal mechanisms were designed to improve on existing manual trash ‘fishing’ tools such as iron rods with fixed hooks. Two of these tools (the ‘claw’ and the ‘hook’) showed promising laboratory results and were subsequently field tested in Mzuzu, Malawi. Both tools proved more efficient than the current tools used in the field and have potential for use in Malawi. DA - 2017/2/14/ PY - 2017/2/14/ DO - 10.2166/washdev.2017.106 VL - 7 IS - 1 SP - 85-91 J2 - J Water Sanit Hyg Dev LA - en OP - SN - 2043-9083 2408-9362 UR - http://dx.doi.org/10.2166/washdev.2017.106 DB - Crossref KW - auger KW - developing countries KW - Excrevator KW - pit emptying KW - trash removal ER - TY - CONF TI - Thermomechanical fatigue response and constitutive modeling for Haynes 230 AU - Morrison, M. AU - Ahmed, R. AU - Hassan, T. AB - Design by analysis is usually performed by commercially available finite element analysis (FEA) software. Constitutive models available in the FEA software are developed and validated using limited experimental data. Hence, a broad set of thermomechanical fatigue experiments with strain dwell at compressive peaks are performed to understand local fatigue failure responses of high temperature components. This study developed a unified viscoplastic model based on nonlinear kinematic hardening of Chaboche type with added features of strain range dependence, rate dependence, temperature dependence, static recovery, and mean stress evolution. The robustness of the constitutive model is demonstrated by comparing its simulations against the experimental responses. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and piping conference, 2016, vol 5 DA - 2017/// DO - 10.1115/pvp2016-63283 ER - TY - JOUR TI - Successive linear approximation methods for leak detection in water distribution systems AU - Berglund, A. AU - Areti, V. S. AU - Brill, D. AU - Mahinthakumar, G. T2 - Journal of Water Resources Planning and Management AB - In many modern water networks, an emerging trend is to measure pressure at various points in the network for operational reasons. Because leaks typically induce a signature on pressure, these routine measurements can be used to develop nonintrusive leak detection approaches. This research employs successive linear approximation methods, based on linear programming and mixed integer linear programming, in a simulation-optimization framework to explore an alternative leak detection methodology for urban water distribution networks based on pressure measurements. The methods attempt to minimize the absolute differences between observed and simulated pressure values at the sensors to determine a linear combination of leaks that most closely approximates the observed pressure pattern. Steady-state and time-varying models of differing complexity (from small published networks to a 27,000-node network for a U.S. utility) were used to test the method. Results are presented to illustrate the method’s effectiveness under different conditions. The methods are shown to work well when pervasive pressure data and hydraulic models representing true operational conditions are available. The methods developed in this work are not intended to replace traditional leak detection methods; rather, they are meant to work in concert with available methods to more accurately and efficiently isolate leak locations and reduce water loss. DA - 2017/// PY - 2017/// DO - 10.1061/(asce)wr.1943-5452.0000784 VL - 143 IS - 8 ER - TY - JOUR TI - Social network conformity and construction work plan reliability AU - Abbasian-Hosseini, S. Alireza AU - Liu, Min AU - Hsiang, Simon M. T2 - AUTOMATION IN CONSTRUCTION AB - In a large construction project delivery is usually handled by numerous subcontractors. Work plan reliability (WPR) of subcontractors is an essential element for improving project performance. Previous research mainly focused on the consequence of the WPR variability of a subcontractor on the following subcontractors in the project task-sequence. Construction industry lacks a good understanding of the social aspect of the subcontractors' WPR. Plausibly and arguably, construction subcontractors and their interactions/relationships in a project constitute a network, conceptualized as a “social network”. “Social conformity” is one of the various social influence types that results in a change of performance/behavior in order to fit in a group. This research aims to understand how conformity plays a role in the subcontractors' performance particularly in their WPR. The objective of this paper is to develop an analytical approach to 1) demonstrate the impact of conformity on the WPR of subcontractors, and 2) identify the role of social network in conformity occurrence in a construction project. Two construction projects, each including a general contractor overseeing several subcontractors, were studied. Findings show that deviation from norms decreases as project proceeds. It also shows that the tendency of subcontractors to follow the norms of their neighborhood (local) is higher than their willing to follow the project norm (global). The research contributes to the body of knowledge as it proposes a social network based approach for the first time to explore how the subcontractors' WPR in a construction project can be under the influence of the conformity phenomenon. Understanding the subcontractors' manner can be useful for project managers when they need to establish a long-term working relationship with a particular subcontractor, or when they need to know much effort is necessary to spend on improvement initiatives of planning reliability. DA - 2017/6// PY - 2017/6// DO - 10.1016/j.autcon.2017.01.004 VL - 78 SP - 1-12 SN - 1872-7891 KW - Social network analysis KW - Job site interactions KW - Social influence KW - Conformity KW - Construction subcontractors KW - Work plan reliability ER - TY - JOUR TI - Probabilistic risk assessment framework for structural systems under multiple hazards using Bayesian statistics AU - Kwag, Shinyoung AU - Gupta, Abhinav T2 - NUCLEAR ENGINEERING AND DESIGN AB - Conventional probabilistic risk assessment (PRA) methodologies (USNRC, 1983; IAEA, 1992; EPRI, 1994; Ellingwood, 2001) conduct risk assessment for different external hazards by considering each hazard separately and independent of each other. The risk metric for a specific hazard is evaluated by a convolution of the fragility and the hazard curves. The fragility curve for basic event is obtained by using empirical, experimental, and/or numerical simulation data for a particular hazard. Treating each hazard as an independently can be inappropriate in some cases as certain hazards are statistically correlated or dependent. Examples of such correlated events include but are not limited to flooding induced fire, seismically induced internal or external flooding, or even seismically induced fire. In the current practice, system level risk and consequence sequences are typically calculated using logic trees to express the causative relationship between events. In this paper, we present the results from a study on multi-hazard risk assessment that is conducted using a Bayesian network (BN) with Bayesian inference. The framework can consider statistical dependencies among risks from multiple hazards, allows updating by considering the newly available data/information at any level, and provide a novel way to explore alternative failure scenarios that may exist due to vulnerabilities. DA - 2017/4/15/ PY - 2017/4/15/ DO - 10.1016/j.nucengdes.2017.02.009 VL - 315 SP - 20-34 SN - 1872-759X KW - Multi-hazard risk assessment KW - Bayesian networks KW - Bayesian inference KW - Vulnerability beyond design basis ER - TY - JOUR TI - Prediction of Full-Scale GAC Adsorption of Organic Micropollutants AU - Kennedy, Anthony M. AU - Reinert, Allison M. AU - Knappe, Detlef R. U. AU - Summers, R. Scott T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - The principal goal of this research was to develop a new scale-up procedure with which the adsorption of organic micropollutants (MPs) by granular activated carbon (GAC) can be predicted from bench-scale tests. To develop scale-up approaches, the adsorption of 29 environmentally relevant MPs was studied in both pilot-scale GAC adsorbers and rapid small-scale column tests that were based on the proportional diffusivity design (PD-RSSCT). Four surface waters with different dissolved organic carbon (DOC) concentrations were spiked with MPs at ng/L levels and tested in PD-RSSCTs simulating full-scale empty bed contact times of 7 and 15 min. Corresponding pilot-scale tests showed MP breakthrough occurred earlier than in PD-RSSCTs, and MP-specific differences between the PD-RSSCT and pilot column breakthrough curves were described by fouling parameters. On average, the PD-RSSCT overpredicted pilot-scale MP breakthrough by a factor of 3.0 ± 1.2 (n = 101). Two approaches were developed for predicting bed volumes that can be treated to 10% MP breakthrough in full-scale adsorbers (BV10%,full-scale). In the first approach, a predictive relationship for the fouling parameter was developed and based on the MP to DOC concentration ratio in the adsorber influent, BVs to 10% MP breakthrough in the PD-RSSCT (BV10%,PD-RSSCT), and pH-dependent octanol–water partition coefficient (log D). In the second approach, BV10%,full-scale was directly predicted from BV10%,PD-RSSCT. These relationships were verified by adequately predicting full-scale GAC breakthrough curves for several MPs in a fifth water from a drinking water treatment plant on the Ohio River. DA - 2017/7// PY - 2017/7// DO - 10.1089/ees.2016.0525 VL - 34 IS - 7 SP - 496-507 SN - 1557-9018 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85024364062&partnerID=MN8TOARS KW - adsorption KW - dissolved organic matter KW - granular activated carbon KW - organic micropollutants KW - rapid small-scale column test ER - TY - JOUR TI - Laboratory Evaluation of Workability and Moisture Susceptibility of Warm-Mix Asphalt Mixtures Containing Recycled Asphalt Pavements AU - Kusam, Abhilash AU - Malladi, Haritha AU - Tayebali, Akhtarhusein A. AU - Khosla, N. Paul T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - Warm mix asphalt (WMA) and recycled asphalt pavements (RAP) are two popularly used sustainable technologies in pavement industry. Because RAP materials contain aged binder, its use is limited to a certain percentage in hot mix asphalt (HMA) as it may affect the workability and, fatigue and thermal cracking performance. Higher percentages of RAP can be incorporated into HMA with softer asphalt binder or in combination with softening agent. However, the combination of WMA and RAP may allow for greater percentages of RAP without modifying the original HMA job mix formula. The objective of this study was to explore the use of higher percentage of RAP, using two different WMA technologies—Evotherm additive and foamed asphalt—to study the workability and moisture sensitivity of WMA-RAP asphalt mixtures. The study found that the use of WMA technologies can eliminate the need for a softer grade binder in high RAP mixtures. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)mt.1943-5533.0001825 VL - 29 IS - 5 SP - SN - 1943-5533 KW - Warm mix asphalt KW - Reclaimed asphalt pavement (RAP) KW - Tensile strength ratio (TSR) KW - Moisture susceptibility KW - Workability ER - TY - JOUR TI - Investigating the mechanical and fatigue properties of sustainable cement emulsified asphalt mortar AU - Moghadas Nejad, Fereidoon AU - Habibi, Mehran AU - Hosseini, Payam AU - Jahanbakhsh, Hamid T2 - JOURNAL OF CLEANER PRODUCTION AB - With regard to the construction of high speed railways, the role of cement emulsified asphalt mortar (CEAM) is of crucial importance as a leveling and damping material. In this respect, there are many research studies on exploring the mechanical, durability, fatigue, and rheological characteristics of CEAM. Nonetheless, developing greener types of CEAMs would be of great interest for developing transportation infrastructures with low carbon footprint. Accordingly, the current study aims to evaluate the effects of partial replacement of cement with low pozzolanic activity ground granulated blast furnace slag (GGBFS) and silica fume (SF) on mechanical and fatigue performances of CEAM. In addition, a central composite design (CCD) with response surface methodology (RSM) was applied to the results to develop statistical models. The results obtained reveal that utilizing low pozzolanic activity GGBFS showed no significant effect on uniaxial compressive strength (UCS) and decreased the indirect tensile strength (IDT) slightly. Moreover, both UCS and IDT heightened through the inclusion of SF. As a result, the addition of SF would compensate for reduction in some mechanical properties caused by GGBFS with low pozzolanicity. Furthermore, based on the results, semi-circular bending (SCB) test properly differentiated the effects of cement replacement with GGBFS and SF on fatigue resistance of CEAM. DA - 2017/7/10/ PY - 2017/7/10/ DO - 10.1016/j.jclepro.2017.04.105 VL - 156 SP - 717-728 SN - 1879-1786 KW - Cement emulsified asphalt mortar (CEAM) KW - Waste materials KW - Mechanical properties KW - Fatigue performance KW - Response surface methodology ER - TY - CONF TI - Improving simulations for low cycle fatigue and ratcheting responses of elbows AU - Islam, N. AU - Hassan, T. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and piping conference, 2016, vol 5 DA - 2017/// ER - TY - CONF TI - Evaluation of durability and waterproofing characteristic of cast-in-place piles using surfactant grout at the field tests AU - Lee, J. AU - Do, J. AU - Kim, H. AU - Park, B. AB - In case of underground construction affected by groundwater, CIP (cast-in-place pile) method is generally used to solve the geohydraulic problem. However, as this method has poor connectivity between piles, an auxiliary cut-off method is required in many cases. In this study, a newly-developed cut-off wall (H-CIP) without auxiliary method, by using surfactant grout (Hi-FA), which improves anti-washout performance and infiltration ability, is introduced and the field applicability of H-CIP method is evaluated. CIP and H-CIP piles were installed under the same ground conditions and field and laboratory tests were conducted to verify the performance, respectively. As a result, a newly-contrived H-CIP method shows higher field performance in terms of cut-off and strength than conventional CIP method. C2 - 2017/// C3 - Grouting 2017: grouting, drilling, and verification DA - 2017/// DO - 10.1061/9780784480793.012 SP - 124-132 M1 - 288 ER - TY - JOUR TI - Evaluation of Externality Costs in Life-Cycle Optimization of Municipal Solid Waste Management Systems AU - Martinez-Sanchez, Veronica AU - Levis, James W. AU - Damgaard, Anders AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. AU - Astrup, Thomas F. T2 - Environmental Science & Technology AB - The development of sustainable solid waste management (SWM) systems requires consideration of both economic and environmental impacts. Societal life-cycle costing (S-LCC) provides a quantitative framework to estimate both economic and environmental impacts, by including “budget costs” and “externality costs”. Budget costs include market goods and services (economic impact), whereas externality costs include effects outside the economic system (e.g., environmental impact). This study demonstrates the applicability of S-LCC to SWM life-cycle optimization through a case study based on an average suburban U.S. county of 500 000 people generating 320 000 Mg of waste annually. Estimated externality costs are based on emissions of CO2, CH4, N2O, PM2.5, PM10, NOx, SO2, VOC, CO, NH3, Hg, Pb, Cd, Cr (VI), Ni, As, and dioxins. The results indicate that incorporating S-LCC into optimized SWM strategy development encourages the use of a mixed waste material recovery facility with residues going to incineration, and separated organics to anaerobic digestion. Results are sensitive to waste composition, energy mix and recycling rates. Most of the externality costs stem from SO2, NOx, PM2.5, CH4, fossil CO2, and NH3 emissions. S-LCC proved to be a valuable tool for policy analysis, but additional data on key externality costs such as organic compounds emissions to water would improve future analyses. DA - 2017/3/6/ PY - 2017/3/6/ DO - 10.1021/acs.est.6b06125 VL - 51 IS - 6 SP - 3119-3127 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.6b06125 DB - Crossref ER - TY - JOUR TI - Effect of Reclaimed Asphalt Pavement Content and Binder Grade on Fatigue-Resisting Performance of Asphalt Mixtures in Georgia AU - Norouzi, Amirhossein AU - Kim, Y. Richard AU - Kim, S. Sonny AU - Yang, Jidong T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - This paper examines the effects of reclaimed asphalt pavement (RAP) content and binder grade on the fatigue resistance of Georgia asphalt concrete mixtures. The asphalt concrete mixtures were prepared based on two job mix formulas used in northern and southern Georgia and were composed of 12.5-mm nominal maximum aggregate size aggregate and three asphalt binders (PG 64-22, PG 67-22, and PG 76-22). Dynamic modulus and controlled crosshead cyclic tension fatigue tests were performed using the laboratory-prepared specimens. A simplified viscoelastic continuum damage (S-VECD) model was characterized for each mixture using the dynamic modulus and fatigue test results. The layered viscoelastic pavement analysis for critical distresses (LVECD) program was used to investigate the effects of RAP content and binder grade on the fatigue performance of pavements. The S-VECD model and LVECD program analyses showed that the addition of RAP up to 30% using corrected optimum asphalt content (COAC) method significantly improved the mixtures’ fatigue resistance, especially for the mixtures with PG 64-22 and PG 67-22 binders. DA - 2017/9// PY - 2017/9// DO - 10.1061/(asce)mt.1943-5533.0001960 VL - 29 IS - 9 SP - SN - 1943-5533 KW - Cyclic tension fatigue test KW - Simplified viscoelastic continuum damage (S-VECD) model KW - Layered viscoelastic pavement analysis for critical distresses (LVECD) program KW - Corrected optimum asphalt content (COAC) ER - TY - JOUR TI - Characterization of pit latrines to support the design and selection of emptying tools in peri-urban Mzuzu, Malawi AU - Chiposa, Rashid AU - Holm, Rochelle H. AU - Munthali, Chimuleke AU - Chidya, Russel C. G. AU - de los Reyes, Francis L., III T2 - Journal of Water Sanitation and Hygiene for Development AB - The urban areas of many low-income countries must balance a rising demand for pit latrines for household sanitation provision against limitations in space, resulting in a need for pit latrine emptying services. This study was undertaken in the peri-urban neighborhood of Area 1B in the city of Mzuzu, Malawi, to examine the characteristics of household pit latrines for designing and selecting pit latrine emptying tools. We used 150 structured household surveys and field observations. From this, a subset was selected and 30 manual cone penetrometer tests were conducted at full latrines. Chemical oxygen demand analysis was also performed for 14 pit latrines. The results indicated that in addition to serving as a disposal for fecal matter, 90% of households also used pit latrines for domestic waste. Only 10% of the studied pit latrines were lined. The filling rate in the study area is calculated to be about three years, and no respondents reported previous emptying. It is suggested pit latrine emptying technology development focuses on a maximum tool diameter of 10 cm to fit through the keyhole (squat hole) and height of 146 cm to fit inside the superstructure, as well as supporting unlined pits and the ability to pump trash. DA - 2017/1/24/ PY - 2017/1/24/ DO - 10.2166/washdev.2017.096 VL - 7 IS - 1 SP - 151-155 J2 - J Water Sanit Hyg Dev LA - en OP - SN - 2043-9083 2408-9362 UR - http://dx.doi.org/10.2166/washdev.2017.096 DB - Crossref KW - fecal sludge management KW - low-income countries KW - Malawi KW - pit emptying KW - pit latrine ER - TY - JOUR TI - Characterization of PM2.5 exposure concentration in transport microenvironments using portable monitors AU - Li, Zhiyuan AU - Che, Wenwei AU - Frey, H. Christopher AU - Lau, Alexis K. H. AU - Lin, Changqing T2 - ENVIRONMENTAL POLLUTION AB - Recently, portable monitors have been increasingly used to quantify air pollutant concentrations at high spatiotemporal resolution. A sampling campaign was conducted to measure the fine particulate matter (PM2.5) and carbon monoxide (CO) exposure concentrations in transport microenvironments (TMEs) in Hong Kong in January and June 2015 using TSI DustTrak and Q-Trak portable monitors. The objectives were to: (1) calibrate DustTrak and Q-Trak; (2) evaluate variability between seasons and microenvironments; (3) estimate indoor/outdoor relationships; and (4) determine minimum sample size. Calibration equations, obtained through side-by-side measurement against stationary reference methods in winter and summer, were applied to correct the measured PM2.5 data set. In general, PM2.5 concentrations in all TMEs were significantly higher in winter than in summer. The mean PM2.5 concentration in winter was lower for underground sections of the Mass Transit Railway (MTR) metro system (31 μg/m3) than for other TMEs, whereas in summer TMEs had mean PM2.5 concentrations in the range of 10–15 μg/m3, with above-ground MTR train as an exception, at 23 μg/m3. PM2.5 concentrations measured in TMEs were strongly correlated with nearby air quality monitoring stations (AQMSs) measurements in winter, but in summer there was little correlation. The minimum sample size estimates varied more among TMEs in summer versus winter because of the differences in PM2.5 concentration distributions related to changes in ambient PM2.5 concentrations and ventilation practices. This study provides a feasible protocol on the calibration and application of portable monitors in TME air quality measurement and develops a method for estimating minimum sample size. DA - 2017/9// PY - 2017/9// DO - 10.1016/j.envpol.2017.05.039 VL - 228 SP - 433-442 SN - 1873-6424 UR - https://doi.org/10.1016/j.envpol.2017.05.039 KW - Portable monitors KW - PM2.5 KW - Transport microenvironments KW - Minimum sample size KW - Hong Kong ER - TY - JOUR TI - An overview of incentive policies for the expansion of renewable energy generation in electricity power systems and the Brazilian experience AU - Aquila, Giancarlo AU - Pamplona, Edson de Oliveira AU - Queiroz, Anderson Rodrigo AU - Rotela Junior, Paulo AU - Fonseca, Marcelo Nunes T2 - RENEWABLE & SUSTAINABLE ENERGY REVIEWS AB - Energy production from renewable sources is already a reality in many countries, and with that, different strategies for incentivizing investments in renewable energy generation have been proposed and used over the years. In this study, long-term policies that have been applied in several countries, such as feed-in tariffs, shares with commercialization of certificates, auctions, and net metering, are overviewed and discussed. The main advantages and disadvantages of these incentive strategies are emphasized, focusing on applications. Some of these strategies that have already been applied in Brazil are analyzed in greater depth, emphasizing the potentialities and fragilities of these mechanisms observed within the country. Even though it is a country that stands out in relation to other Latin American countries regarding electricity generation from non-hydro renewable sources, Brazil still faces barriers that prevent a utilization compatible with its potential. Moreover, the trend for renewable sources, such as wind and solar power, is to represent an energy capacity reserve to cover hydrological risks and also to contribute to a distributed generation spread through electricity distribution networks. DA - 2017/4// PY - 2017/4// DO - 10.1016/j.rser.2016.12.013 VL - 70 SP - 1090-1098 SN - 1364-0321 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85007613506&partnerID=MN8TOARS KW - Renewable energy generation KW - Incentive policies KW - Electricity power systems KW - Long-term planning ER - TY - JOUR TI - 2016: A Year in Review AU - Gabr, Mohammed T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)gt.1943-5606.0001730 VL - 143 IS - 5 SP - SN - 1943-5606 UR - https://doi.org/10.1061/(ASCE)GT.1943-5606.0001730 ER - TY - JOUR TI - Subgrade resilient modulus prediction using light-weight deflectometer data AU - Mousavi, S. Hamed AU - Gabr, Mohammed A. AU - Borden, Roy H. T2 - Canadian Geotechnical Journal AB - Resilient modulus has been used for decades as an important parameter in pavement structure design. Resilient modulus, like other elasticity moduli, increases with increasing confining stress and decreases with increasing deviatoric stress. Several constitutive models have been proposed in the literature to calculate resilient modulus as a function of stress state. The most recent model, recommended by the Mechanistic–empirical pavement design guide (MEPDG) and used in this paper, calculates resilient modulus as a function of bulk stress, octahedral shear stress, and three fitting coefficients: k 1 , k 2 , and k 3 . Work in this paper presents a novel approach for predicting resilient modulus of subgrade soils at various stress levels based on light-weight deflectometer (LWD) data. The proposed model predicts the MEPDG resilient modulus model coefficients (k 1 , k 2 , and k 3 ) directly from the ratio of applied stress to surface deflection measured during LWD testing. The proposed model eliminates uncertainties associated with needed input parameters for surface modulus (E LWD ) calculation, such as the selection of an appropriate value of Poisson’s ratio for the soil layer and shape factor. The proposed model was validated with independent data from other studies reported in the literature. DA - 2017/3// PY - 2017/3// DO - 10.1139/cgj-2016-0062 VL - 54 IS - 3 SP - 304-312 J2 - Can. Geotech. J. LA - en OP - SN - 0008-3674 1208-6010 UR - http://dx.doi.org/10.1139/cgj-2016-0062 DB - Crossref KW - resilient modulus KW - light-weight deflectometer KW - subgrade KW - Mechanistic-empirical pavement design guide ( MEPDG). ER - TY - JOUR TI - Stress-strain response of A706 grade 80 reinforcing steel AU - Overby, David AU - Kowalsky, Mervyn AU - Seracino, Rudolf T2 - Construction and Building Materials AB - Before ASTM A706 grade 80 rebar may be specified in the seismic design of structures, its mechanical properties must be well understood and calibrated on a statistical basis. Based on the results of 788 tensile tests of A706 grade 80 rebar encompassing bar sizes No. 4–No. 18 (approx. metric No. 13–No. 57), five major stress-strain parameters are statistically evaluated and used to develop recommendations for an expected monotonic stress-strain curve. An existing material model is shown to accurately capture the shape of the monotonic stress-strain curve. Additional tests are used to evaluate the strain-aging performance of the steel. DA - 2017/8// PY - 2017/8// DO - 10.1016/j.conbuildmat.2017.03.200 VL - 145 SP - 292-302 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/j.conbuildmat.2017.03.200 DB - Crossref KW - Seismic KW - Reinforced concrete KW - Reinforcing steel KW - Grade 80 ER - TY - JOUR TI - Steam Application to Destroy Foam-Forming Bacteria in Activated Sludge Systems AU - Cubbage, Laurissa E. AU - Pitt, Paul A. AU - Stone, Alan L. AU - He, Xia AU - L. de los Reyes III, Francis T2 - Journal of Environmental Engineering AB - The use of steam to destroy filamentous foam-forming bacteria was explored as an alternative foam control measure in activated sludge systems. The effects of combinations of steam pressure and exposure time on decreasing filaments, foam potential, and foam stability were evaluated. Statistically significant decreases in mycolata (of nocardioform morphology) abundance were observed at pressures of 275.6, 344.5, 413.4, and 482.3 kPa (40, 50, 60, and 70 psi, respectively) after exposure to steam for 60 min. Lower mycolata abundance levels were obtained at all 482.3-kPa treatments, with the lowest abundance at exposure times of 60 min. Although Microthrix parvicella is less sensitive to the steam treatment than mycolata, slight decreases in Microthrix parvicella abundance were observed at all pressures after 60 min of exposure. Although no drastic changes in foam potential were observed, foam stability was greatly affected by the treatments, leading to nonstable foam formation. The application of steam treatment shows promise in reducing foaming in activated sludge and subsequent downstream solids handling facilities, and is an advantage of thermal hydrolysis processes, which are rapidly gaining acceptance in the industry. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)ee.1943-7870.0001183 VL - 143 IS - 5 SP - 06017001 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001183 DB - Crossref ER - TY - JOUR TI - Ruggedness Study of Dynamic Modulus Testing of Asphalt Concrete in Indirect Tension Mode AU - Norouzi, Amirhossein AU - Kim, Y. Richard T2 - JOURNAL OF TESTING AND EVALUATION AB - The modulus is one of the primary asphalt mixture properties used for the mechanistic performance prediction of asphalt pavements. Dynamic modulus testing is a common method of measuring mixture modulus as a function of loading frequencies and temperatures. This paper presented the results of a ruggedness study of dynamic modulus testing in indirect tension mode to evaluate the factors that were most likely to affect the final results. Specimen thickness, air void content, gauge length, test temperature, and horizontal strain level, which are the critical factors that affect the dynamic modulus of asphalt concrete, were selected for the ruggedness analysis. Two different asphalt mixtures with the participation of two laboratories were used in the study. Based on the selected values for the different variables, air void content was found to be the significant factor that affected dynamic modulus testing and dynamic modulus values. The other factors did not appear to have a major impact on the test results; however, reasonable tolerances were obtained for the other parameters investigated in this paper. DA - 2017/3// PY - 2017/3// DO - 10.1520/jte20150118 VL - 45 IS - 2 SP - 601-612 SN - 1945-7553 KW - asphalt materials KW - field cores KW - dynamic modulus testing KW - indirect tension KW - ruggedness analysis ER - TY - JOUR TI - Retrospective Analysis of Wisconsin's Landfill Organic Stability Rule AU - Bareither, Christopher A. AU - Barlaz, Morton A. AU - Doran, Michael AU - Benson, Craig H. T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - AbstractThe Wisconsin Department of Natural Resources introduced an organic stability rule (OSR) in 2007 to encourage effective management of organic waste in landfills and ultimately reduce the du... DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)ee.1943-7870.0001192 VL - 143 IS - 5 SP - SN - 1943-7870 KW - Case study KW - Landfill KW - Methane KW - Municipal solid waste KW - Organic stability ER - TY - JOUR TI - Individual temperature based models for nondestructive evaluation of complex moduli in asphalt concrete AU - Sakhaeifar, Maryam S. AU - Kim, Y. Richard AU - Montano, Blanca E. Garcia T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The rheological properties of bituminous materials play important roles in the selection of paving materials, and analysis and design of asphalt pavements. The series of models developed in this study are composed of five formulations for the creation of the dynamic modulus mastercurve at a wide range of testing temperatures. The predictability of these models is assessed by comparing the predicted dynamic modulus mastercurves of different mixtures with measured ones from a nondestructive impact resonance (IR) test. This assessment shows that the predictions match the dynamic modulus values measured from different techniques with a good level of accuracy. DA - 2017/4/15/ PY - 2017/4/15/ DO - 10.1016/j.conbuildmat.2016.12.145 VL - 137 SP - 117-127 SN - 1879-0526 KW - Hot mix asphalt concrete KW - Dynamic modulus KW - Predictive model KW - Time-temperature superposition KW - Nondestructive evaluation KW - Mechanistic-Empirical Pavement Design KW - Guide ER - TY - JOUR TI - Fuel Use and Pollutant Emissions Taxonomy for Heavy Duty Diesel Construction Equipment AU - Lewis, Phil AU - Rasdorf, William T2 - JOURNAL OF MANAGEMENT IN ENGINEERING AB - The purpose of this paper is to present a taxonomy of fuel use and pollutant emissions rates for heavy duty diesel (HDD) equipment to assist equipment managers in estimating the energy and environmental effects of their fleets. Diesel fuel is the primary energy source for HDD equipment. Without it, the equipment is inoperable and nonproductive. Estimating fuel requirements can be extremely difficult because of high variability in published fuel consumption rates. Moreover, equipment publications provide no insight into pollutant emissions rates. The taxonomy was based on real-world fuel consumption and emissions data collected from in-use equipment. An engine modal analysis was conducted on the data to categorize it by engine load. Weighted average fuel use and pollutant emissions rates were calculated based on the results of the engine modal analysis. The taxonomy presents weighted average fuel use and emissions rates according to equipment type; Environmental Protection Agency (EPA) engine-tier technology type; and pollutants, including nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), and particulate matter (PM). The taxonomy provides an accurate and easy-to-use guide to assist equipment managers in estimating fuel consumption and consequential pollutant emissions. DA - 2017/3// PY - 2017/3// DO - 10.1061/(asce)me.1943-5479.0000484 VL - 33 IS - 2 SP - SN - 1943-5479 ER - TY - JOUR TI - Evaluating the liquefaction potential of gravel soils with static experiments and steady state approaches AU - Do, Jinung AU - Heo, Seoung-Beom AU - Yoon, Yeo-Won AU - Chang, Ilhan T2 - KSCE JOURNAL OF CIVIL ENGINEERING DA - 2017/3// PY - 2017/3// DO - 10.1007/s12205-016-1365-9 VL - 21 IS - 3 SP - 642-651 SN - 1976-3808 KW - liquefaction KW - gravel soils KW - static triaxial test KW - steady state KW - state parameter ER - TY - JOUR TI - Determining Specimen Geometry of Cylindrical Specimens for Direct Tension Fatigue Testing of Asphalt Concrete AU - Lee, Jong-Sub AU - Norouzi, Amirhossein AU - Kim, Y. Richard T2 - JOURNAL OF TESTING AND EVALUATION AB - Abstract This paper presented a specimen geometry study of cylindrical specimens used in the direct tension cyclic (DTC) fatigue testing of asphalt concrete using an asphalt mixture performance tester. The current specimen geometry for DTC fatigue testing is 100 mm in diameter and 150 mm in height with a linear variable differential transducer (LVDT) gauge length of 70 mm in the middle of the specimen. In order to use the displacement data for mechanistic fatigue performance modeling, specimen failure must occur within the length of the LVDT gauge. However, recent experiments using stiff mixtures have shown that failure often occurs outside the LVDT gauge length. This specimen geometry study was conducted to determine the specimen geometry that enhances the propensity of the failure inside the gauge length without sacrificing the advantage of the DTC testing that provides uniform stresses and strains in the middle of the specimen. Laboratory experiments were performed on cylindrical specimens of different geometries (i.e., different diameters and lengths). Test specimen diameters of 75 mm and 100 mm and specimen heights of 130 mm and 150 mm were used in this study. The specimen geometry effects on damage characteristic curves and failure criteria were identified through ANOVA tests and layered viscoelastic pavement analysis for critical distresses (LVECD) program. Based on analysis results and experimental verification tests, the specimen geometry recommended for the DTC testing is 100 mm in diameter and 130 mm in height with a 70-mm gauge length. The recommended specimen geometry is applicable when the gyratory-compacted specimen geometry is 150 mm in diameter and more than 178 mm in height. DA - 2017/3// PY - 2017/3// DO - 10.1520/jte20140357 VL - 45 IS - 2 SP - 613-623 SN - 1945-7553 KW - asphalt mixture KW - specimen geometry KW - damage characteristic KW - failure criteria KW - direct tension cyclic fatigue testing ER - TY - JOUR TI - Determination of Dynamic Modulus Values of Asphalt Mixtures Using Impact Resonance Testing of Thin Disk Specimens AU - Kim, D. AU - Kim, Y. R. T2 - JOURNAL OF TESTING AND EVALUATION AB - The impact resonance (IR) test is a nondestructive test method that is used to characterize the linear viscoelastic behavior of asphalt concrete. This method is preferred over other methods because the setup of the IR test is simpler, more efficient, and less expensive than standard axial compression dynamic modulus (|E*|) tests. Researchers originally developed the IR test method for cylindrical specimens of asphalt mixtures and concluded that this method can serve as an alternative to |E*| tests. However, the geometry (100 mm in diameter by 150 mm in height) of the cylindrical specimens used in these tests prohibits the use of IR tests for field cores. Therefore, researchers began to consider thin disk-shaped specimens for IR testing because thinner geometry of such specimens better represents slices of field cores. In this study, a test procedure was developed to evaluate the use of thin disk-shaped specimens for IR tests in order to determine the |E*| values of asphalt mixtures. The IR test protocol was optimized using 2 IR test methods (referred to as Case 1 and Case 2 in this work) under various test conditions to ensure the highest possible quality of the data. Optimal test methods were proposed based on the repeatability and variability of the resonant frequency and phase angle data and the ability of the different test conditions to provide data that best match the |E*| values obtained from standard axial compression |E*| tests. The results demonstrate that the |E*| values of thin disk-shaped specimens determined from the optimized IR tests are similar to the |E*| values of long cylindrical specimens determined from conventional |E*| AASHTO T 342-11 tests and IR tests. DA - 2017/3// PY - 2017/3// DO - 10.1520/jte20150076 VL - 45 IS - 2 SP - 509-520 SN - 1945-7553 KW - dynamic modulus (vertical bar E*vertical bar) KW - impact resonance (IR) KW - resonant frequency KW - phase angle KW - thin disk-shaped specimens KW - field cores ER - TY - JOUR TI - Complex Adaptive Systems Framework to Simulate the Performance of Hydrant Flushing Rules and Broadcasts during a Water Distribution System Contamination Event AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman T2 - Journal of Water Resources Planning and Management AB - In the event that a contaminant is introduced to a water distribution system, utility managers must respond quickly to protect public health. Mitigation strategies specify response actions, such as warning consumers to reduce water activities using the news media and flushing contaminated water at hydrants. The performance of alternative response actions may be influenced by sociotechnical dynamics, as consumer reactions to contaminant exposure and information about the event can change water demands, hydraulics, propagation of a contaminant plume, and public health consequences. This research develops a modeling framework to test and evaluate mitigation decisions that a utility manager may take to protect public health over a wide range of contamination events. An agent-based modeling framework is developed to integrate social behaviors with technical artifacts in a sociotechnical model to evaluate the public health consequences of a water event. Social actors, including consumers and utility managers, are represented as agents and are coupled with a water distribution network model and a news media model to evaluate the performance of response strategies. Strategies for flushing hydrants are encoded as decision trees that specify the location and timing of hydrant flushing, based on the activation of water-quality sensors. The agent-based model is described using the Overview, Design, and Details protocol and is demonstrated for a virtual midsized municipality, Mesopolis. Results compare the effectiveness of flushing hydrants using cautious and adaptive response strategies and the use of the news media to disseminate warning messages. The framework can be applied for cities to evaluate alternative management strategies. DA - 2017/4// PY - 2017/4// DO - 10.1061/(asce)wr.1943-5452.0000744 VL - 143 IS - 4 SP - 04017001 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(ASCE)WR.1943-5452.0000744 DB - Crossref KW - Sociotechnical modeling KW - Agent-based modeling KW - Water quality KW - Contamination event KW - Mitigation strategies KW - News media ER - TY - JOUR TI - Characteristics of Exposure to Particles due to Incense Burning inside Temples in Kanpur, India AU - Goel, Anubha AU - Wathore, Roshan AU - Chakraborty, Tirthankar AU - Agrawal, Manish T2 - AEROSOL AND AIR QUALITY RESEARCH AB - Incense burning in temples is a common and popular ritual in India and other Asian countries. This study aims at assessing the quantity and size segregated distribution of particulate matter in temples of Kanpur city, India. Active air sampling was performed in three temples using the Micro Orifice Uniform Deposit Impactor (MOUDI). PM10 mass concentrations as high as 2184 µg m–3 were recorded inside the temples. Mass concentration values for all samples exceeded the Central Pollution Control Board (CPCB) National Ambient Air Quality Standard (NAAQS) of 100 µg m–3. Particle counts were high, and more than 99% of the numbers of particles generated were PM2.5. Particle coagulation is an active mechanism leading to formation of polydispersed particles. Most abundant particles occur in the accumulation mode (dp < 1 µm). Ventilation conditions and amount of incense burned are major factors affecting particle size distribution. Exposure through inhalation, to critically high concentrations of fine particulate matter generated via incense smoke especially for worshippers who frequent the temple and temple workers, raises health concerns. The results clearly indicate that incense smoke is a major source of particulate matter in the temple microenvironment and their chemical characteristics need further examination. DA - 2017/2// PY - 2017/2// DO - 10.4209/aaqr.2016.04.0146 VL - 17 IS - 2 SP - 608-615 SN - 2071-1409 KW - Indoor air quality KW - Incense burning KW - MMAD KW - Most abundant PM size ER - TY - JOUR TI - Approach to Assessing Tradeoffs between Construction Equipment Fleet Emissions and Cost AU - Hummer, Joseph E. AU - Arocho, Ingrid AU - Rasdorf, William T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - The environmental effects of construction equipment emissions have been studied in previous research. Total emissions for construction activities and projects were previously calculated for various transportation projects as well as for other project types. This paper focuses on how contractors can use different equipment combinations and make project schedule adjustments to reduce total emissions from construction projects. It presents a newly developed optimization model that companies can use to select a fleet for a particular project to achieve the reductions. The model can be used to minimize total equipment cost and total emissions, or to minimize total equipment cost while limiting (capping) emissions for one or more of six pollutants. When the model was applied to example construction projects, the predicted reductions in emissions were significant, ranging from 25 to 85% depending on the pollutant. When the model was used to minimize cost, a reduction of 63% of the total equipment cost was achieved from the minimum-emissions solution. The lower-cost solution also resulted in a 43% reduction in project duration from the minimum-emission solution. The major contribution of this paper is the development of a decision model that can be used to select construction equipment fleets to reduce emissions production or equipment cost. The model can be customized to take into consideration the equipment fleet available for each activity and can be developed in concert with preliminary activity scheduling to look at daily emissions. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)co.1943-7862.0001255 VL - 143 IS - 5 SP - SN - 1943-7862 ER - TY - JOUR TI - A functionally layered sensing skin for the detection of corrosive elements and cracking AU - Seppanen, Aku AU - Hallaji, Milad AU - Pour-Ghaz, Mohammad T2 - STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL AB - In this paper, we propose an electrical impedance tomography (EIT)-based multifunctional surface sensing system, or sensing skin, for structural health monitoring. More specifically, the EIT-based sensing skin is developed for detecting and localizing the ingress of chlorides and cracking: two phenomena which are of concern in many structures, including reinforced concrete structures. The multifunctional sensing skin is made of two layers: one layer is sensitive to both chlorides and cracking, and the other layer is sensitive to cracking only. In the experiments, the sensing skin is tested on a polymeric and concrete substrate. The results demonstrate the feasibility of using the multifunctional multi-layer sensing skin for detecting and localizing corrosive elements and cracking, and for distinguishing between them. DA - 2017/3// PY - 2017/3// DO - 10.1177/1475921716670574 VL - 16 IS - 2 SP - 215-224 SN - 1741-3168 KW - Damage detection KW - electrical impedance tomography (EIT) KW - multi-layer sensing skin KW - reinforced concrete KW - cracking KW - corrosion ER - TY - CONF TI - Unified viscoplasticity modeling features needed for simulation of grade 91 creep and fatigue responses AU - Islam, N. AU - Dewees, D. AU - Hassan, T. AB - Chaboche unified viscoplasticity model and uncoupled plasticity and creep models (nonunified) are evaluated for their capability in simulating low-cycle fatigue, creep and creep-fatigue responses of Grade 91 steel. The primary objective of this study is to develop a constitutive model incorporating various advanced modeling features for design-by-analysis of elevated temperature power plant components. For validation of the model a broad set of experimental responses of Grade 91 in the temperature range 20–600°C are collected from literature. Performance of the models is demonstrated against simulating these experimental responses. It is demonstrated that the unified Chaboche model simulation capability can be improved through implementing strain range dependence, cyclic hardening through kinematic hardening rule and static recovery modeling features. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference, 2016, Vol 6a DA - 2017/// DO - 10.1115/pvp2016-63578 ER - TY - JOUR TI - Structural fragility of T-joint connections in large-scale piping systems using equivalent elastic time-history simulations AU - Tadinada, Sashi Kanth AU - Gupta, Abhinav T2 - STRUCTURAL SAFETY AB - The main focus of the paper is to evaluate seismic fragility of nonlinear connections in large piping systems. Piping systems in general exhibit damage due to excessive inelastic deformation at discrete locations such as T-joints, elbows, valves, etc., and low ductility corresponding to failure. Since the supporting structure remains primarily elastic, this study evaluates the effectiveness of using linearization techniques to describe the localized nonlinearities with equivalent elastic properties. A concept called “Equivalent Elastic Limit State” is introduced. A large number of representative nonstructural systems which are essentially linear but characterized by localized fragile nonlinearities are studied to propose a model for computing seismic fragility curves using only elastic time-history simulations. It is shown that the seismic fragility evaluated using elastic analyses is close to the actual fragility. Fragility estimated using this approach can be used as a very reliable prior estimate within Bayesian fragility models so that the posterior estimate of fragility curve can be obtained using a very few number of nonlinear time-history analyses. The efficacy of the model is illustrated for seismic fragility analysis of a full-scale piping system in a hospital with fragile 2″ T-joint connections. DA - 2017/// PY - 2017/// DO - 10.1016/j.strusafe.2016.12.003 VL - 65 SP - 49-59 SN - 1879-3355 KW - Structural fragility KW - Piping systems KW - Equivalent linearization KW - Bayesian updating KW - Earthquake time history analysis ER - TY - JOUR TI - Relating Public Opinions of Roadway Assets to Field Data with Survey and Focus Groups AU - Davis, Joy AU - Cunningham, Chris AU - Findley, Daniel AU - Searcy, Sarah AU - Martin, James AU - Watkins, Lonnie T2 - TRANSPORTATION RESEARCH RECORD AB - In recent years, transportation policy in the United States has increasingly focused on measuring and tracking performance outcomes. However, identifying how quantifiable outcomes—such as international roughness index ratings—influence less tangible outcomes—such as user satisfaction with a roadway—can be challenging. This paper outlines a method that enables researchers to compare stakeholder perceptions of assets with actual field-measured data for roadways. More than 350 residents in six locations in the state of North Carolina were surveyed about how those residents perceived and prioritized the roadway assets managed by the North Carolina Department of Transportation. Using a method termed “roadway reviews,” researchers asked participants about state-maintained roads as the participants were driven on those roads in real time; these surveys were supplemented with focus groups. In addition to identifying how well asset conditions on roadway segments aligned with the basic expectations of roadway users, researchers determined how these ratings compared with field measurements for the segments and captured how participants ranked the importance of specific roadway assets for overall condition, safety, and appearance. The findings will be used to improve asset management practice and will be integrated into the North Carolina Department of Transportation’s annual Highway Performance Monitoring System reports. DA - 2017/// PY - 2017/// DO - 10.3141/2613-03 VL - 2613 IS - 2613 SP - 16-28 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85015798523&partnerID=MN8TOARS ER - TY - JOUR TI - Multi-scenario optimization approach for assessing the impacts of advanced traffic information under realistic stochastic capacity distributions AU - Li, Mingxin AU - Rouphail, Nagui M. AU - Mahmoudi, Monirehalsadat AU - Liu, Jiangtao AU - Zhou, Xuesong T2 - TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES AB - In this study, to incorporate realistic discrete stochastic capacity distribution over a large number of sampling days or scenarios (say 30–100 days), we propose a multi-scenario based optimization model with different types of traveler knowledge in an advanced traveler information provision environment. The proposed method categorizes commuters into two classes: (1) those with access to perfect traffic information every day, and (2) those with knowledge of the expected traffic conditions (and related reliability measure) across a large number of different sampling days. Using a gap function framework or describing the mixed user equilibrium under different information availability over a long-term steady state, a nonlinear programming model is formulated to describe the route choice behavior of the perfect information (PI) and expected travel time (ETT) user classes under stochastic day-dependent travel time. Driven by a computationally efficient algorithm suitable for large-scale networks, the model was implemented in a standard optimization solver and an open-source simulation package and further applied to medium-scale networks to examine the effectiveness of dynamic traveler information under realistic stochastic capacity conditions. DA - 2017/4// PY - 2017/4// DO - 10.1016/j.trc.2017.01.019 VL - 77 SP - 113-133 SN - 0968-090X KW - Stochastic road capacity KW - Traffic assignment KW - Travel time variability KW - Value of dynamic traveler information KW - Risk-sensitive route choice behavior ER - TY - JOUR TI - Micromechanical characterization of shales through nanoindentation and energy dispersive x-ray spectrometry AU - Veytskin, Yuriy B. AU - Tammina, Vamsi K. AU - Bobko, Christopher P. AU - Hartley, Patrick G. AU - Clennell, Michael B. AU - Dewhurst, David N. AU - Dagastine, Raymond R. T2 - GEOMECHANICS FOR ENERGY AND THE ENVIRONMENT AB - Shales are heterogeneous sedimentary rocks which typically comprise a variable mineralogy (including compacted clay particles sub-micrometer in size), silt grains, and nanometer sized pores collectively arranged with transversely isotropic symmetry. A detailed understanding of the micro- and sub-microscale geomechanics of these minerals is required to improve models of shale strength and stiffness properties. In this paper, we propose a linked experimental–computational approach and validate a combination of grid nanoindentation and Scanning Electron Microscopy (SEM) with Energy and Wavelength Dispersive X-ray Spectrometry (EDS/WDS) at the same spatial locations to identify both the nano-mechanical morphology and local mineralogy of these nanocomposites. The experimental parameters of each method are chosen to assess a similar volume of material. By considering three different shales of varying mineralogy and mechanical diversity, we show through the EMMIX statistical iterative technique that the constituent phases, including highly compacted plate- or sheet-like clay particles, carbonates, silicates, and sulfides, have distinct nano-mechanical morphologies and associated indentation moduli and hardness. Nanoindentation-based strength homogenization analysis determines an average clay packing density, friction coefficient, and solid cohesion for each tested shale sample. Comparison of bulk to microscale geomechanical properties, through bulk porosimetry measurements, reveals a close correspondence between bulk and microscale clay packing densities. The determination of mechanical microstructure and material properties is useful for predictive microporomechanical models of the stiffness and strength properties of shale. The experimental and computational approaches presented here also apply to other chemically and mechanically complex materials exhibiting nanogranular, composite behavior. DA - 2017/3// PY - 2017/3// DO - 10.1016/j.gete.2016.10.004 VL - 9 SP - 21-35 SN - 2352-3808 KW - Micromechanical characterization KW - Shale KW - Nanoindentation KW - Energy and wavelength dispersive x-ray spectrometry KW - Scanning electron microscopy KW - Strength homogenization KW - Cathodoluminescence ER - TY - JOUR TI - Land loss by pond expansion on the Mississippi River Delta Plain AU - Ortiz, Alejandra C. AU - Roy, Samapriya AU - Edmonds, Douglas A. T2 - GEOPHYSICAL RESEARCH LETTERS AB - Abstract The world's river deltas may collapse under the combined effects of rising sea levels, subsidence, and reduced sediment supply. Saving these deltaic environments requires quantifying processes driving collapse. In the Mississippi River Delta, rapid land loss offers an important opportunity to test existing theories for marsh collapse. We use Landsat images to examine how pond expansion by edge retreat contributes to land loss over 34 years in the Atchafalaya‐Vermillion, Terrebonne, and Barataria basins of the Mississippi Delta. Tracking the area changes in ponds on the marsh surface, we find a striking consistency between pond expansion direction and the dominant wind direction and show that wind‐generated waves are capable of causing edge erosion. Expansion rate increases rapidly for ponds wider than 300 m in Terrebonne and Barataria basins. From this, we suggest that ponds in Atchafalaya‐Vermillion basin are stable, whereas ponds in Terrebonne and Barataria are unstable. DA - 2017/4/28/ PY - 2017/4/28/ DO - 10.1002/2017gl073079 VL - 44 IS - 8 SP - 3635-3642 SN - 1944-8007 ER - TY - JOUR TI - Improvement of very soft ground by a high-efficiency vacuum preloading method: A case study AU - Zheng, Gang AU - Liu, Jingjin AU - Lei, Huayang AU - Rahman, M. S. AU - Tan, Zaikun T2 - MARINE GEORESOURCES & GEOTECHNOLOGY AB - This paper describes a full-scale test on a very soft clay ground around 70,000 m2, which is conducted in Huizhou of Guangdong Province, China, to present a new method of vacuum preloading method. A novel moisture separator was developed, which can automatically regulate the vacuum pressure variation by changing the volume of the gas inside it. A large quantity of water drained by the proposed moisture separators can be directly used as a surcharge loading, which would shorten the ground improvement time and save costs as well. Three levels of silt-prevention prefabricated vertical drains were used in the treating process to accelerate the consolidation. In addition, the vacuum preloading method also included an effective radial drainage device which would strengthen the dredged soft clay fill in a deep layer. In the in situ test, tens of piezometers and settlement plates were installed to measure the variations of excess pore water pressures and settlement of two stages of observation points at different positions in the ground. The results show that the largest average consolidation settlement was 314.1 cm and made a saving of more than 66% in power consumption compared with traditional method. It demonstrates that this adopted method is an efficient, cost-effective, and environmentally friendly method for improving sites with low bearing capacity and high compressibility soils. DA - 2017/// PY - 2017/// DO - 10.1080/1064119x.2016.1215363 VL - 35 IS - 5 SP - 631-642 SN - 1521-0618 KW - Case studies KW - cost-effectiveness KW - hydraulic fills KW - prefabricated vertical drains KW - preloading KW - soil improvement ER - TY - JOUR TI - Cobalt-Doped Iron Sulfide as an Electrocatalyst for Hydrogen Evolution AU - Huang, Sheng-Yang AU - Sodano, Daniel AU - Leonard, Thomas AU - Luiso, Salvatore AU - Fedkiw, Peter S. T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - Iron disulfide (FeS2) promises an earth-abundant, low-cost alternative to platinum group metals for the hydrogen evolution reaction (HER), but its performance is currently limited by reactivity of active sites and poor electrical conductivity. Here we employ Ketjenblack (KB) as a support to create an Fe-based electrocatalyst with high-electrical conductivity and maximal active sites. Moreover, a systematic study on the role of cobalt (Co) dopant was carried out. Electrochemical results show enhancements in HER activity of Co-doped FeS2 [FexCo1−xS2, atomic content of Fe (x) = 0.98 – 0.32] in comparison to un-doped FeS2 in acidic electrolyte (pH = 0). The overpotential necessary to drive a current density of 10 mA/cm2 is −0.150 V and only decreases by 1 mV after 500 cycles of a durability test (cycling the potential between 0.0 and −0.15 V), indicating a long-term durability in acidic environment. This work suggests that FexCo1−xS2 offers a viable approach to improve the activity and durability of transition metal-sulfide electrocatalysts. DA - 2017/// PY - 2017/// DO - 10.1149/2.0761704jes VL - 164 IS - 4 SP - F276-F282 SN - 1945-7111 ER - TY - JOUR TI - An Earth's Future Special Collection: Impacts of the coastal dynamics of sea level rise on low-gradient coastal landscapes AU - Kidwell, David M. AU - Dietrich, J. Casey AU - Hagen, Scott C. AU - Medeiros, Stephen C. T2 - Earth's Future AB - Abstract Rising sea level represents a significant threat to coastal communities and ecosystems, including altered habitats and increased vulnerability to coastal storms and recurrent inundation. This threat is exemplified in the northern Gulf of Mexico, where low topography, marshes, and a prevalence of tropical storms have resulted in extensive coastal impacts. The ability to facilitate adaptation and mitigation measures relies, in part, on the development of robust predictive capabilities that incorporate complex biological processes with physical dynamics. Initiated in 2010, the 6‐year Ecological Effects of Sea Level Rise—Northern Gulf of Mexico project applied a transdisciplinary science approach to develop a suite of integrated modeling platforms informed by empirical data that are capable of evaluating a range of climate change scenarios. This special issue highlights resultant integrated models focused on tidal hydrodynamics, shoreline morphology, oyster ecology, coastal wetland vulnerability, and storm surges that demonstrate the need for dynamic models to incorporate feedbacks among physical and biological processes in assessments of sea level rise effects on coastal systems. Effects are projected to be significant, spatially variable and nonlinear relative to sea level rise rates. Scenarios of higher sea level rise rates are projected to exceed thresholds of wetland sustainability, and many regions will experience enhanced storm surges. Influenced by an extensive collaborative stakeholder engagement process, these assessments on the coastal dynamics of sea level rise provide a strong foundation for resilience measures in the northern Gulf of Mexico and a transferable approach for application to other coastal regions throughout the world. DA - 2017/1// PY - 2017/1// DO - 10.1002/2016ef000493 VL - 5 IS - 1 SP - 2-9 J2 - Earth's Future LA - en OP - SN - 2328-4277 UR - http://dx.doi.org/10.1002/2016EF000493 DB - Crossref KW - sea level rise KW - wetlands KW - tidal hydrodynamics KW - storm surge KW - Gulf of Mexico KW - sedimentation ER - TY - JOUR TI - Verification of the applicability of the time-temperature superposition principle to interface shear stiffness and strength of GlasGrid-reinforced asphalt mixtures AU - Cho, Seong Hwan AU - Safavizadeh, Seyed Amirshayan AU - Kim, Y. Richard T2 - ROAD MATERIALS AND PAVEMENT DESIGN AB - This paper aims to verify the applicability of the time–temperature superposition (t–TS) principle to the interface shear performance of GlasGrid-reinforced asphalt specimens under monotonic and random cyclic shear loading. A double shear tester and a direct shear device, the Modified Advance Shear Tester that has the capability to apply confining loads, were used to fulfil this objective. Double-layered asphalt specimens were fabricated and reinforced using two types of fibreglass grids with 12.5-mm and 25-mm grid openings, respectively. PG 64-22 asphalt binder was used as the tack coat when the smaller opening grid was used, and SS-1 emulsion was applied as the tack coat when the larger opening grid was used. Approaches that employ the mixture dynamic modulus, tack coat residue complex modulus, and interface shear modulus shift factors for shifting the shear test results and constructing shear master curves were evaluated. The results show that the t–TS principle is applicable to the shear strength and shear stiffness of GlasGrid-reinforced asphalt concrete specimens if the right shift factor function is used. DA - 2017/7// PY - 2017/7// DO - 10.1080/14680629.2016.1189350 VL - 18 IS - 4 SP - 766-784 SN - 2164-7402 KW - time-temperature superposition (t-TS) principle KW - interface shear performance KW - fibreglass grid KW - shift factors KW - tack coat ER - TY - JOUR TI - Robust sacrificial polymer templates for 3D interconnected microvasculature in fiber-reinforced composites AU - Patrick, J.F. AU - Krull, B.P. AU - Garg, M. AU - Mangun, C.L. AU - Moore, J.S. AU - Sottos, N.R. AU - White, S.R. T2 - Composites Part A: Applied Science and Manufacturing AB - A promising pathway for multifunctionality in fiber-composites is to mimic biological vasculature that enables living organisms with concerted homeostatic functions. In this paper, newfound material and processing advancements in vaporization of sacrificial components (VaSC), a technique for creating inverse replica architectures via thermal depolymerization of a sacrificial template, are established for enhanced vascular composites manufacturing. Sacrificial poly(lactic acid) with improved distribution of catalytic micro-particles is extruded into fibers for automated weaving and filament feedstock for 3-D printing. Fiber drawing after extrusion improves mechanical robustness for high-fidelity, composite preform weaving. Joining one-dimensional (1D) interwoven fibers with printed sacrificial (2D) templates affords three-dimensional (3D) interconnected networks in a fiber-composite laminate that inherits damage-tolerant features found in natural vasculatures. In addition to providing a conduit for enhanced functionality, the sacrificial templating techniques are compatible with current composites manufacturing processes, materials, and equipment. DA - 2017/9// PY - 2017/9// DO - 10.1016/j.compositesa.2017.05.022 VL - 100 SP - 361-370 J2 - Composites Part A: Applied Science and Manufacturing LA - en OP - SN - 1359-835X UR - http://dx.doi.org/10.1016/j.compositesa.2017.05.022 DB - Crossref KW - Multifunctional composites KW - Microstructures KW - 3-D printing KW - Weaving ER - TY - JOUR TI - Reinforced Concrete Behavior, Research, Development, and Design through Partial-Interaction Mechanics AU - Oehlers, Deric J. AU - Visintin, Phillip AU - Chen, Jian-Fei AU - Seracino, Rudolf AU - Wu, Yufei AU - Lucas, Wade T2 - Journal of Structural Engineering AB - Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. DA - 2017/7// PY - 2017/7// DO - 10.1061/(ASCE)ST.1943-541X.0001764 VL - 143 IS - 7 SP - 02517002 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001764 DB - Crossref ER - TY - JOUR TI - Quantifying travel time variability at a single bottleneck based on stochastic capacity and demand distributions AU - Li, Mingxin AU - Zhou, Xuesong AU - Rouphail, Nagui M. T2 - JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS AB - Travel time reliability, an essential factor in traveler route and departure time decisions, serves as an important quality of service measure for dynamic transportation systems. This article investigates a fundamental problem of quantifying travel time variability from its root sources: stochastic capacity and demand variations that follow commonly used log-normal distributions. A volume-to-capacity ratio-based travel time function and a point queue model are used to demonstrate how day-to-day travel time variability can be explained from the underlying demand and capacity variations. One important finding is that closed-form solutions can be derived to formulate travel time variations as a function of random demand/capacity distributions, but there are certain cases in which a closed-form expression does not exist and numerical approximation methods are required. This article also uses probabilistic capacity reduction information to estimate time-dependent travel time variability distributions under conditions of non-recurring traffic congestion. The proposed models provide theoretically rigorous and practically useful tools for understanding the causes of travel time unreliability and evaluating the system-wide benefit of reducing demand and capacity variability. DA - 2017/// PY - 2017/// DO - 10.1080/15472450.2016.1163639 VL - 21 IS - 2 SP - 79-93 SN - 1547-2442 KW - bottleneck KW - stochastic capacity KW - stochastic demand KW - travel time variability ER - TY - JOUR TI - Quantifying Level of Microbial-Induced Cementation for Cyclically Loaded Sand AU - Feng, Kai AU - Montoya, Brina M. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING AB - Microbial-induced calcite precipitation (MICP) is a novel soil-improvement technique that improves the behavior of sands subjected to dynamic loading. The level of cementation of MICP-treated sands is commonly quantified using mass of calcite precipitation; however, mass of calcite is not a unique measure for material behavior as other factors, such as the distribution of calcite precipitation at the particle contacts, would also affect the mechanical behavior of MICP-treated sands. Therefore, mass of calcite alone may not be appropriate to characterize material behavior. This study illustrates the importance of using shear-wave velocity in addition to mass of calcite to quantify the level of MICP cementation to the corresponding material behavior, since shear-wave velocity is not only affected by the mass of calcite, but also influenced by the distribution of calcite precipitation at the particle contacts. Two specimens are cemented with the MICP process to the same mass of calcite value but to different shear-wave velocities and then cyclically loaded. The observed mechanical behavior of the specimens indicates the specimen with higher shear-wave velocity possesses larger liquefaction resistance compared to the specimen with lower shear velocity, which provides evidence that the material behavior of MICP-treated sands is not only affected by the precipitated mass of calcite, but also influenced by the distribution pattern of calcite precipitation. DA - 2017/6// PY - 2017/6// DO - 10.1061/(asce)gt.1943-5606.0001682 VL - 143 IS - 6 SP - SN - 1943-5606 KW - Microbial-induced calcite precipitation KW - Cemented sands KW - Shear-wave velocity KW - Cyclic shear strength ER - TY - JOUR TI - Piping Fragility Evaluation: Interaction With High-Rise Building Performance AU - Ju, Bu Seog AU - Gupta, Abhinav AU - Ryu, Yong Hee T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - Many recent studies have emphasized the need for improving seismic performance of nonstructural systems in critical facilities in order to reduce the damage as well as to maintain continued operation of the facility after an earthquake. This paper is focused on evaluating system-level seismic fragility of the piping in a representative high-rise building. Piping fragilities are evaluated by incorporating the nonlinear finite-element model of a threaded Tee-joint that is validated using experimental results. The emphasis in this study is on evaluating the effects of building performance on the piping fragility. The differences in piping fragility due to the nonlinearities in building are evaluated by comparing the fragility curves for linear frame and nonlinear fiber models. It is observed that as nonlinearity in the building increases with increasing value of peak ground acceleration, the floor accelerations exhibit a reduction due to degradation/softening. Consequently, the probabilities of failure increase at a slower rate relative to that in a linear frame. It is also observed that a piping located at higher floor does not necessarily exhibits high fragilities, i.e., the fundamental building mode is not always the governing mode. Higher order building modes with frequencies closest to critical piping modes of interest contribute more significantly to the piping fragility. Within a particular building mode of interest, a good indicator of the amplification at different floor levels can be obtained by the product of mode shape ordinate and modal participation factor. Piping fragilities are likely to be higher at floor levels at which this product has a higher value. DA - 2017/6// PY - 2017/6// DO - 10.1115/1.4034406 VL - 139 IS - 3 SP - SN - 1528-8978 KW - piping fragility KW - threaded Tee-joint performance KW - building-piping interaction KW - first-leakage limit state ER - TY - JOUR TI - Performance-Based Reliability of ASME Piping Design Equations AU - Gupta, Abhinav AU - Saigal, Rakesh K. AU - Ryu, Yonghee T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - In this paper, we present an exploratory study on the evaluation of reliability levels associated with the piping design equations specified by ASME Boiler and Pressure Vessel (BPV) Code, Section III. Probabilistic analyses are conducted to evaluate reliability levels in straight pipe segments with respect to performance functions that characterize the different failure criteria using advanced first-order reliability method (AFORM). One important failure criterion considered in this study relates to the plastic instability which forms the basis of piping design equations for emergency and faulted load level conditions as defined in the ASME code. The code-specified definition of plastic instability is based on the evaluation of a collapse moment which is defined using the moment–curvature curve for a particular component. In this study, we use elastic-perfectly plastic, bilinear kinematic hardening, and multilinear kinematic hardening stress–strain curves to develop closed-form expressions for the moment–curvature relationship in a straight unpressurized pipe. Both the pressurized and the unpressurized loading conditions are considered. The closed-form reliability is evaluated using Monte Carlo simulation because of the complex nature of the closed-form expression. The reliability values are calculated with respect to the maximum allowable moment specified by the code design equations that use deterministic safety factors. DA - 2017/6// PY - 2017/6// DO - 10.1115/1.4034584 VL - 139 IS - 3 SP - SN - 1528-8978 KW - LRFD design for piping KW - piping reliability KW - reliability-based code calibration KW - performance-based design of piping ER - TY - JOUR TI - Out-of-Plane Buckling of Ductile Reinforced Structural Walls due to In-Plane Loads AU - Kelly Herrick, C. AU - Kowalsky, Mervyn J. T2 - Journal of Structural Engineering AB - AbstractReinforced structural walls are often implemented as a lateral force resisting system in multistory buildings, designed to deform elastically under wind loads and form plastic hinges at their base under seismic excitation. Past research suggests plastic tensile demands and subsequent load reversals can cause a plastic, localized lateral instability in walls. Although lateral stability is addressed by some building codes, plastic buckling is rarely directly addressed. In 2010 and 2011, New Zealand experienced earthquakes that damaged many structural wall buildings, and plastic buckling was observed. This paper re-examines two existing local buckling models using a range of data sources. A review of prior experimental work assesses the models’ accuracy at predicting plastic buckling capacities. A parametric study on a range of walls examines the variables most influential to affect plastic buckling capacities. Additionally, three nonlinear time history analyses of buildings subjected to the 2010 and... DA - 2017/3// PY - 2017/3// DO - 10.1061/(asce)st.1943-541x.0001660 VL - 143 IS - 3 SP - 04016182 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001660 DB - Crossref KW - Special design issues KW - Structural walls KW - Wall buckling KW - Local instability ER - TY - JOUR TI - Modeling fats, oil and grease deposit formation and accumulation in sewer collection systems AU - Yousefelahiyeh, Roya AU - Dominic, Christopher Cyril Sandeep AU - Ducoste, Joel T2 - JOURNAL OF HYDROINFORMATICS AB - Fats, oil and grease (FOG) deposits in sewer systems are responsible for approximately 25% of all annual line blockages in the United States and lead to the release of 3–10 million gallons of untreated wastewater to the surrounding environment. Considerable effort has been made to maintain the conveyance of wastewater by cleaning pipes that have a significant FOG deposit accumulation. Changes in the urban landscape from the addition or deletion of food service establishments (FSEs), however, may pose challenges in determining the location of these high accumulation zones. This research focuses on the development of a sewer collection system model that predicts high FOG deposit accumulation zones. Two collection systems were simulated to test the prediction capabilities of the tool and to assess how changes in the urban landscape affect the location of these accumulation zones. The numerical tool incorporates a mechanistic-based FOG deposit formation kinetic model. Results showed that the model predicts about 65% of the reported high FOG deposit accumulating zones. Simulations also showed significant changes in the location of these high FOG deposit accumulating zones from changes in the number and locations of FSEs and from FSE discharge and background wastewater flow variations. DA - 2017/5// PY - 2017/5// DO - 10.2166/hydro.2017.016 VL - 19 IS - 3 SP - 443-455 SN - 1465-1734 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85018765260&partnerID=MN8TOARS KW - FOG deposits KW - food service establishment KW - numerical modeling KW - sanitary sewer overflows KW - sewer collection system KW - wastewater conveyance ER - TY - JOUR TI - Mechanistic performance evaluation of pavement sections containing RAP and WMA additives in Manitoba AU - Kim, Dahae AU - Norouzi, Amirhossein AU - Kass, Said AU - Liske, Tara AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Over recent decades, the utilization of reclaimed asphalt pavement (RAP) and warm mix asphalt (WMA) in mixtures has increased dramatically due to the environmental and economic advantages of these materials. This paper presents the fatigue and rutting characterization of mixtures that contain RAP and/or WMA obtained from Manitoba in Canada. In addition to mechanical testing, numerical simulations of the fatigue cracking and rutting performance of the pavement sections were performed, and the results were compared to field observations. The results obtained from the Layered Viscoelastic pavement analysis for Critical Distresses (LVECD) program and from the field measurements show good agreement, thereby indicating that the LVECD program is able to predict reasonable pavement performance for the RAP and WMA mixtures. The field performance and the predicted performance were used to evaluate the effects of RAP and/or WMA additives on the fatigue cracking and rutting performance of the mixtures. DA - 2017/2/15/ PY - 2017/2/15/ DO - 10.1016/j.conbuildmat.2016.12.035 VL - 133 SP - 39-50 SN - 1879-0526 KW - Asphalt pavement KW - RAP KW - WMA KW - Fatigue cracking KW - Rutting KW - TSS test KW - S-VECD test KW - LVECD program ER - TY - JOUR TI - Mechanistic evaluation of fatigue cracking in asphalt pavements AU - Norouzi, Amirhossein AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - Over the last several decades, significant research has been conducted to predict the fatigue cracking performance of asphalt pavements. Recently, the simplified viscoelastic continuum damage (S-VECD) model was developed as an efficient method of characterising the fatigue performance of asphalt mixtures under a wide range of loading conditions. Two important material properties that can be determined from the S-VECD model are the damage characteristic curve that defines how damage evolves in a specimen and the energy-based failure criterion that defines when the specimen fails. These two material functions are unique for a given mixture regardless of temperature, mode of loading, stress/strain amplitude and loading history. This study presents the application of the Layered Viscoelastic Crirtical Distresses (LVECD) programme to predict the fatigue performance of 18 pavement sections from different locations in the United States and Canada. The capability of the LVECD programme to capture crack initiation, crack propagation and damage in the pavement sections is investigated by comparing the simulation results with field observations. This study found reasonable agreement in trends between the damage growth throughout the pavement cross sections as predicted by the LVECD programme and the surface crack growth as evidenced by field observations. DA - 2017/// PY - 2017/// DO - 10.1080/10298436.2015.1095909 VL - 18 IS - 6 SP - 530-546 SN - 1477-268X KW - Asphalt pavement KW - S-VECD model KW - fatigue failure criterion KW - field observations KW - LVECD programme ER - TY - JOUR TI - Initial Residual Stresses in Hot-Rolled Wide-Flange Shapes: A Computational Technique and Influence on Structural Performances AU - Quayyum, Shahriar AU - Hassan, Tasnim T2 - JOURNAL OF STRUCTURAL ENGINEERING AB - Wide-flange members are hot-rolled to their final shapes and subsequently air-cooled, during which residual stresses are developed due to nonuniform cooling. Both global and local flange-buckling strengths and the seismic performance of W-shaped columns are influenced by initial residual stresses (IRSs). Hence, it is essential to accurately predict the magnitude and distribution of IRSs to investigate their influence on structural performance. However, most of the literature either ignores IRSs or assumes their simplified distribution. This study developed a simple computational scheme to simulate IRSs and their distribution in hot-rolled W shapes. The IRS simulation technique is validated against the measured data in the literature for different W-shape sizes. Good conformity is observed between the simulated and measured data. IRSs due to uneven cooling can be as high as one-half of the yield stress and can significantly affect the load-carrying capacity and deformation of W-shaped members. The numerical scheme developed provides a simple experimentally validated technique for simulating IRSs in hot-rolled W shapes for use in structural analysis and design of moment-resisting connections and frames. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)st.1943-541x.0001739 VL - 143 IS - 5 SP - SN - 1943-541X KW - Initial residual stresses KW - Hot-rolled W shape KW - Buckling KW - Seismic performance KW - Residual stress simulation KW - Analysis and computation ER - TY - CONF TI - Influence of notch geometry on the notch vicinity stress and strain responses AU - Robert, A. AU - Morrison, M. L. AU - Hassan, T. AB - The most common method used to determine the crack initiation life of a component containing a stress raiser in the low cycle fatigue regime is to calculate the maximum strain and then to use a strain-life curve. General practice is to base fatigue life estimates on the stabilized strain amplitude and to neglect the effects of transient behavior due to cyclic hardening or softening and ratcheting. For certain structures in which the accumulation of plastic strains may be significant, a separate check may be performed to ensure that these strains remain below a specified level. An objective of this research is to understand the notch tip local strain ratcheting and shakedown through finite element analyses and physical experiments. Towards planning a set of notched flat coupon experiments, this study performed analyses of various notched coupons under force-controlled cyclic loading. A question that will be addressed, what is the notch tip failure mechanism under a force-controlled load cycle with a non-zero mean force? Smooth specimens under such a force-controlled load cycle normally results in strain ratcheting. It is investigated whether notch tip strain responds in a similar manner under a force controlled loading cycle. The analysis results show that the strain ratcheting rate at the notch tip depends on the sharpness of the notch. In case of semi-circular and blunt elliptical notches shakedown of strain ratcheting within 25 cycles is observed, whereas for the sharp elliptical notch strain ratcheting doesn’t shakedown after 300 cycles. A novel observation made from the analysis results is that the mean stress at the notch tip gradually decreases with inelastic cycle while the stress amplitude remains unchanged. These result and future experimental plan on notch specimens are presented in this article. C2 - 2017/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference, 2016, Vol 1A DA - 2017/// DO - 10.1115/pvp2016-63287 ER - TY - JOUR TI - From endogenous to exogenous pattern formation: Invasive plant species changes the spatial distribution of a native ant AU - Li, Kevin AU - He, Yifan AU - Campbell, Susanna K. AU - Colborn, A. Shawn AU - Jackson, Eliot L. AU - Martin, Austin AU - Monagan, Ivan V., Jr. AU - Ong, Theresa Wei Ying AU - Perfecto, Ivette T2 - GLOBAL CHANGE BIOLOGY AB - Abstract Invasive species are a significant threat to global biodiversity, but our understanding of how invasive species impact native communities across space and time remains limited. Based on observations in an old field in Southeast Michigan spanning 35 years, our study documents significant impacts of habitat change, likely driven by the invasion of the shrub, Elaeagnus umbellata , on the nest distribution patterns and population demographics of a native ant species, Formica obscuripes . Landcover change in aerial photographs indicates that E. umbellata expanded aggressively, transforming a large proportion of the original open field into dense shrubland. By comparing the ant's landcover preferences before and after the invasion, we demonstrate that this species experienced a significant unfavorable change in its foraging areas. We also find that shrub landcover significantly moderates aggression between nests, suggesting nests are more related where there is more E. umbellata . This may represent a shift in reproductive strategy from queen flights, reported in the past, to asexual nest budding. Our results suggest that E. umbellata may affect the spatial distribution of F. obscuripes by shifting the drivers of nest pattern formation from an endogenous process (queen flights), which led to a uniform pattern, to a process that is both endogenous (nest budding) and exogenous (loss of preferred habitat), resulting in a significantly different clustered pattern. The number and sizes of F. obscuripes nests in our study site are projected to decrease in the next 40 years, although further study of this population's colony structures is needed to understand the extent of this decrease. Elaeagnus umbellata is a common invasive shrub, and similar impacts on native species might occur in its invasive range, or in areas with similar shrub invasions. DA - 2017/6// PY - 2017/6// DO - 10.1111/gcb.13671 VL - 23 IS - 6 SP - 2250-2261 SN - 1365-2486 KW - autumn olive KW - Elaeagnus umbellata KW - Formica obscuripes KW - invasive species KW - landcover change KW - pattern formation KW - spatial distribution KW - thatching ant ER - TY - JOUR TI - Discrete element method simulations of bio-cemented sands AU - Feng, Kai AU - Montoya, B. M. AU - Evans, T. M. T2 - COMPUTERS AND GEOTECHNICS AB - Microbially induced calcite precipitation (MICP) has emerged as a novel soil improvement method. In this paper, 3-D discrete element method (DEM) simulations are used to explore the behavior of MICP-cemented sands. Comparisons of the macro-scale response of numerical and physical specimens are made. Microstructure analyses indicate a shear band formed in the numerical specimens, consistent with physical experiments. The bond breakage pattern in numerical specimens is explored and compared to observed measurements from physical specimens. The relationship between dilatancy and stress-strain behavior is evaluated. The results indicate DEM is an effective technique to capture the mechanical behavior of MICP-cemented sand. DA - 2017/5// PY - 2017/5// DO - 10.1016/j.compgeo.2016.12.028 VL - 85 SP - 139-150 SN - 1873-7633 KW - Discrete element method KW - Microbial induced calcite precipitation KW - Cemented sand KW - Triaxial tests KW - Shear strength ER - TY - JOUR TI - DIC Technique to Investigate Crack Propagation in Grid-Reinforced Asphalt Specimens AU - Safavizadeh, Seyed Amirshayan AU - Kim, Youngsoo Richard T2 - Journal of Materials in Civil Engineering AB - Crack growth data are among the key parameters needed to characterize the materials used in asphalt concrete fatigue and fracture tests. The purpose of this study is to investigate the use of the digital image correlation (DIC) technique in monitoring the progression of damage and quantifying the length of cracks in asphalt concrete fatigue and fracture tests. To this end, cyclic interlayer shear tests and four-point bending notched beam fatigue tests were performed on double-layer fiberglass grid-reinforced asphalt concrete specimens. The tests were performed at 20°C and at frequencies of 5 and 10 Hz for the cyclic shear and bending beam fatigue tests, respectively. The full-field displacement and strain contours derived from DIC analysis of the specimens’ surface images proved to be powerful tools for monitoring the damage progression in the asphalt specimens under fatigue loading and for developing crack tip detection methods. Crack length measurement methods were developed based on DIC analysis displacement and strain results and were used successfully to determine interfacial crack lengths in the shear tests and vertical and interfacial crack lengths in the four-point bending notched beam fatigue tests. DA - 2017/6// PY - 2017/6// DO - 10.1061/(ASCE)MT.1943-5533.0001839 VL - 29 IS - 6 SP - 04017011 J2 - J. Mater. Civ. Eng. LA - en OP - SN - 0899-1561 1943-5533 UR - http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0001839 DB - Crossref ER - TY - JOUR TI - Construction Project Complexity: Research Trends and Implications AU - Luo, Lan AU - He, Qinghua AU - Jaselskis, Edward J. AU - Xie, Jianxun T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - The rapid growth of complex projects in the construction industry worldwide has triggered a growing number of studies over the past two decades, suggesting that understanding project complexity is a key component of successful construction project management. This study aims to investigate the status and trends in project complexity research through a four-stage literature review that can benefit both researchers and practitioners. Seventy-four relevant articles were identified from studies published during the years 1996–2015, and results indicate that research in construction project complexity primarily focuses on four areas: influencing factors contributing to project complexity, the impact of project complexity, complexity measurement methods, and considerations for managing project complexity. Future research should concentrate on specific factors that drive complexity for different types of construction projects and the development of management guidelines for addressing complexity throughout the project lifecycle. This paper provides both a timely summary of literature in the area of project complexity and insights into opportunities for future study of and guidance for successfully managing complexity in construction projects. DA - 2017/7// PY - 2017/7// DO - 10.1061/(asce)co.1943-7862.0001306 VL - 143 IS - 7 SP - SN - 1943-7862 KW - Construction projects KW - Project complexity KW - Research trends KW - Literature review KW - Project management KW - Organizational issues ER - TY - JOUR TI - A Novel Hybrid Heating Method for Mechanical Testing of Miniature Specimens at Elevated Temperature AU - Li, Lin AU - Ngaile, Gracious AU - Hassan, Tasnim T2 - JOURNAL OF MICRO AND NANO-MANUFACTURING AB - A novel hybrid heating method which combines the conventional electric-resistance specimen heating with microcoil heating of specimen ends to achieve uniform heating over the gauge length is presented. Resistive heating of a miniature specimen develops a parabolic temperature profile with lowest temperature at the grip ends because of the heat loss to the gripper. Coil heating at the specimen ends compensates for this heat loss resulting in uniform temperature distribution over the central segment of the specimen. Thermo-electric finite element simulations were carried out to analyze the transient and steady temperature distribution in miniature specimens followed by experimental validation. DA - 2017/6// PY - 2017/6// DO - 10.1115/1.4035954 VL - 5 IS - 2 SP - SN - 2166-0476 ER - TY - JOUR TI - Tracking cyanobacteria blooms: Do different monitoring approaches tell the same story? AU - Bertani, Isabella AU - Steger, Cara E. AU - Obenour, Daniel R. AU - Fahnenstiel, Gary L. AU - Bridgeman, Thomas B. AU - Johengen, Thomas H. AU - Sayers, Michael J. AU - Shuchman, Robert A. AU - Scavia, Donald T2 - SCIENCE OF THE TOTAL ENVIRONMENT AB - Cyanobacteria blooms are a major environmental issue worldwide. Our understanding of the biophysical processes driving cyanobacterial proliferation and the ability to develop predictive models that inform resource managers and policy makers rely upon the accurate characterization of bloom dynamics. Models quantifying relationships between bloom severity and environmental drivers are often calibrated to an individual set of bloom observations, and few studies have assessed whether differences among observing platforms could lead to contrasting results in terms of relevant bloom predictors and their estimated influence on bloom severity. The aim of this study was to assess the degree of coherence of different monitoring methods in (1) capturing short- and long-term cyanobacteria bloom dynamics and (2) identifying environmental drivers associated with bloom variability. Using western Lake Erie as a case study, we applied boosted regression tree (BRT) models to long-term time series of cyanobacteria bloom estimates from multiple in-situ and remote sensing approaches to quantify the relative influence of physico-chemical and meteorological drivers on bloom variability. Results of BRT models showed remarkable consistency with known ecological requirements of cyanobacteria (e.g., nutrient loading, water temperature, and tributary discharge). However, discrepancies in inter-annual and intra-seasonal bloom dynamics across monitoring approaches led to some inconsistencies in the relative importance, shape, and sign of the modeled relationships between select environmental drivers and bloom severity. This was especially true for variables characterized by high short-term variability, such as wind forcing. These discrepancies might have implications for our understanding of the role of different environmental drivers in regulating bloom dynamics, and subsequently for the development of models capable of informing management and decision making. Our results highlight the need to develop methods to integrate multiple data sources to better characterize bloom spatio-temporal variability and improve our ability to understand and predict cyanobacteria blooms. DA - 2017/1/1/ PY - 2017/1/1/ DO - 10.1016/j.scitotenv.2016.10.023 VL - 575 SP - 294-308 SN - 1879-1026 KW - Cyanobacterial harmful algal blooms KW - Water quality KW - Long-term time series KW - Boosted regression trees KW - Biophysical drivers ER - TY - JOUR TI - The role of natural variability in projections of climate change impacts on U.S. ozone pollution AU - Garcia-Menendez, Fernando AU - Monier, Erwan AU - Selin, Noelle E. T2 - Geophysical Research Letters AB - Abstract Climate change can impact air quality by altering the atmospheric conditions that determine pollutant concentrations. Over large regions of the U.S., projected changes in climate are expected to favor formation of ground‐level ozone and aggravate associated health effects. However, modeling studies exploring air quality‐climate interactions have often overlooked the role of natural variability, a major source of uncertainty in projections. Here we use the largest ensemble simulation of climate‐induced changes in air quality generated to date to assess its influence on estimates of climate change impacts on U.S. ozone. We find that natural variability can significantly alter the robustness of projections of the future climate's effect on ozone pollution. In this study, a 15 year simulation length minimum is required to identify a distinct anthropogenic‐forced signal. Therefore, we suggest that studies assessing air quality impacts use multidecadal simulations or initial condition ensembles. With natural variability, impacts attributable to climate may be difficult to discern before midcentury or under stabilization scenarios. DA - 2017/3/28/ PY - 2017/3/28/ DO - 10.1002/2016gl071565 VL - 44 IS - 6 SP - 2911-2921 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1002/2016GL071565 DB - Crossref KW - ozone KW - air pollution KW - climate change impacts KW - natural variability KW - model projections ER - TY - JOUR TI - The response of polymer optical fiber (POF) to cyclic loading for the application of a POF sensor for automotive seat occupancy sensing AU - Haroglu, Derya AU - Powell, Nancy AU - Seyam, Abdel-Fattah M. T2 - JOURNAL OF THE TEXTILE INSTITUTE AB - The goal of this research aimed to develop an accurate and reproducible textile-based optical fiber sensor for automotive seat occupancy. In our previous publication, the response of perfluorinated (PF) graded index (GI) polymer optical fibers (POFs) (62.5/750 and 62.5/490 μm) to bending and tensile loading was investigated. In this study, the response of the PF GI POFs to cyclic loading was investigated. The repeated loading and unloading the POF sensor would experience due to car vibrations and multiple uses by seat occupants, might cause fatigue failure to the POF sensor. The results showed that the Cytop-1 did not show any permanent deformation up to 500 cycles at strain rates 4 and 60 mm/min at a gage length of 76.2 mm in its elastic sensitive strain region. The Cytop-2 showed permanent deformation at 3.5% strain after 500 cycles at a gage length of 76.2 mm. Thus, the Cytop-1 was found out to be more appropriate to be used as an optical fiber sensor for automotive seat occupancy sensing relative to the Cytop-2. In this study, a theoretical approach of the behavior of PF GI POF to cyclic loading was also provided. DA - 2017/// PY - 2017/// DO - 10.1080/00405000.2015.1133755 VL - 108 IS - 1 SP - 42-48 SN - 1754-2340 KW - Perfluorinated graded index polymer optical fiber KW - OTDR KW - cyclic loading KW - automotive KW - seat occupancy sensing ER - TY - JOUR TI - The response of polymer optical fiber (POF) to bending and axial tension for the application of a POF sensor for automotive seat occupancy sensing AU - Haroglu, Derya AU - Powell, Nancy AU - Seyam, Abdel-Fattah M. T2 - JOURNAL OF THE TEXTILE INSTITUTE AB - The automotive industry is a promising area for innovations in the field of polymer optical fiber (POF) sensors as the industry currently uses the POF mostly for data transmissions. Since an optical fiber sensor has a high bandwidth, is small in size, is lightweight, and is immune to electromagnetic interference, it offers higher performance than that of its electrical-based counterparts such as the strain gage, elastomeric bladder, and resistive sensor systems. This enhanced performance makes an optical fiber sensor a suitable material for sensing seat occupancy for improved safety features in automobiles. The overall goal of this research is to develop a textile-based optical fiber sensor for automotive seat occupancy with high accuracy and reproducibility. In this study, the bending and tensile loading responses of POF were investigated, where two perfluorinated (PF) graded index (GI) POFs with two different core/cladding diameters, 62.5/750 and 62.5/490 μm, were used. The bending loss and the light attenuation against the applied axial stress were measured by a photon counting optical time-domain reflectometer. The critical bending diameters were analyzed: Cytop-1 (62.5/750 μm) ≥ 38.10 mm, Cytop-2 (62.5/490 μm) ≥ 44.45 mm. Furthermore, the elastic sensitive strain regions (x), where the stress-induced loss was recoverable, of the POFs at a 76.2 mm gage length at a strain rate of 4 mm/min were determined: Cytop-1: 3% ≤ x ≤ 3.5%, Cytop-2: 3.1% ≤ x ≤ 3.3%. The Cytop-1 was found to be less sensitive to bending and to have greater elastic sensitive strain range relative to the Cytop-2. In this study, a theoretical approach of the PF GI POF behavior to bending and axial tension was provided. The results demonstrated the feasibility of POFs as optical fiber sensors for automotive seat occupancy sensing. DA - 2017/// PY - 2017/// DO - 10.1080/00405000.2016.1160755 VL - 108 IS - 1 SP - 132-139 SN - 1754-2340 KW - Perfluorinated graded index polymer optical fiber KW - OTDR KW - polymer optical fiber sensor KW - automotive KW - seat occupancy sensing ER - TY - JOUR TI - The importance of open data and software: Is energy research lagging behind? AU - Pfenninger, Stefan AU - DeCarolis, Joseph AU - Hirth, Lion AU - Quoilin, Sylvain AU - Staffell, Iain T2 - ENERGY POLICY AB - Energy policy often builds on insights gained from quantitative energy models and their underlying data. As climate change mitigation and economic concerns drive a sustained transformation of the energy sector, transparent and well-founded analyses are more important than ever. We assert that models and their associated data must be openly available to facilitate higher quality science, greater productivity through less duplicated effort, and a more effective science-policy boundary. There are also valid reasons why data and code are not open: ethical and security concerns, unwanted exposure, additional workload, and institutional or personal inertia. Overall, energy policy research ostensibly lags behind other fields in promoting more open and reproducible science. We take stock of the status quo and propose actionable steps forward for the energy research community to ensure that it can better engage with decision-makers and continues to deliver robust policy advice in a transparent and reproducible way. DA - 2017/2// PY - 2017/2// DO - 10.1016/j.enpol.2016.11.046 VL - 101 SP - 211-215 SN - 1873-6777 KW - Modelling KW - Data KW - Open source KW - Open data KW - Transparency KW - Reproducibility ER - TY - JOUR TI - The Relationship between Land Use and Vulnerability to Nitrogen and Phosphorus Pollution in an Urban Watershed AU - Tasdighi, Ali AU - Arabi, Mazdak AU - Osmond, Deanna L. T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - Characterization of the vulnerability of water bodies to pollution from natural and anthropogenic sources requires understanding the relationship between land use and water quality. This study aims (i) to explore the influence of upstream land use on annual stream water concentrations and loads of total nitrogen (TN) and phosphorus (TP) and (ii) to characterize the vulnerability of water bodies to TN and TP pollution as a function of land use under varying climatic conditions. Multiple linear regression models were used across 23 stream locations within the Jordan Lake watershed in North Carolina between 1992 and 2012 to explore land use-water quality relationships. The percentage of urban land use and wastewater treatment plant capacity were the most important factors with strong ( 0.7) and significant ( < 0.01) positive correlations with annual TN and TP concentrations and loads. Percent agricultural land was negatively correlated with TN in 18 out of 21 yr of the study period. Using analysis of covariance, significant ( 0.01) differences were determined between models developed for urban land use with TN and TP loads based on annual precipitation. Using concentrations instead of loads resulted in a nonsignificant difference between models for average and wet years. Finally, a procedure was developed to characterize the vulnerability to TN and TP pollution, computed as the probability of exceeding the nutrient standard limits. Results indicated that the vulnerability to TN and TP was controlled primarily by urban land use, with higher values in dry years than normal and wet years. DA - 2017/// PY - 2017/// DO - 10.2134/jeq2016.06.0239 VL - 46 IS - 1 SP - 113-122 SN - 1537-2537 ER - TY - JOUR TI - Reassessment of the succession of lactic acid bacteria in commercial cucumber fermentations and physiological and genomic features associated with their dominance AU - Perez-Diaz, I. M. AU - Hayes, J. AU - Medina, E. AU - Anekella, K. AU - Daughtry, K. AU - Dieck, S. AU - Levi, M. AU - Price, R. AU - Butz, N. AU - Lu, Z. AU - Azcarate-Peril, M. A. T2 - FOOD MICROBIOLOGY AB - A compositional re-assessment of the microbiota present in commercial cucumber fermentation using culture independent and dependent methods was conducted, with emphasis on lactic acid bacteria (LAB). Two commercial cucumber fermentation tanks were monitored by measuring pH, dissolved oxygen and temperature, and used as sources of samples for microbial plating, genomic DNA extraction and measurement of organic acids and carbohydrates by HPLC. Six additional commercial tanks were included to identify the dominant microorganisms using molecular methods. A comparative analysis of the publically available genome sequences corresponding to the LAB found in cucumber fermentations was completed to gain an understanding of genomic features possibly enabling dominance. Analyses of the microbiota suggest Lactobacillales prevail in cucumber fermentations, including in order of prevalence Lactobacillus pentosus, Lb. plantarum, Lb. brevis, Weissella spp., Pediococcus ethanolidurans, Leuconostoc spp. and Lactococcus spp. It was observed that Lb. pentosus and Lb. plantarum have comparatively larger genomes, higher gene counts, uniquely distribute the ribosomal clusters across the genome as opposed to close to the origin of replication, and possess more predicted amino acids prototrophies and selected biosynthesis related genes. It is theorized that Lb. pentosus and Lb. plantarum dominance in cucumber fermentations is the result of their genetic make-up. DA - 2017/5// PY - 2017/5// DO - 10.1016/j.fm.2016.11.025 VL - 63 SP - 217-227 SN - 1095-9998 KW - Cucumber fermentation KW - Microbiota KW - Genome comparative analysis KW - Lactobacillus pentosus KW - Lactobacillus plantarum KW - Dominance ER - TY - JOUR TI - National Estimate of Per- and Polyfluoroalkyl Substance (PFAS) Release to U.S. Municipal Landfill Leachate AU - Lang, Johnsie R. AU - Allred, B. McKay AU - Field, Jennifer A. AU - Levis, James W. AU - Barlaz, Morton A. T2 - Environmental Science & Technology AB - Landfills are the final stage in the life cycle of many products containing per- and polyfluoroalkyl substances (PFASs) and their presence has been reported in landfill leachate. The concentrations of 70 PFASs in 95 samples of leachate were measured in a survey of U.S. landfills of varying climates and waste ages. National release of PFASs was estimated by coupling measured concentrations for the 19 PFASs where more than 50% of samples had quantifiable concentrations, with climate-specific estimates of annual leachate volumes. For 2013, the total volume of leachate generated in the U.S. was estimated to be 61.1 million m3, with 79% of this volume coming from landfills in wet climates (>75 cm/yr precipitation) that contain 47% of U.S. solid waste. The mass of measured PFASs from U.S. landfill leachate to wastewater treatment plants was estimated to be between 563 and 638 kg for 2013. In the majority of landfill leachate samples, 5:3 fluorotelomer carboxylic acid (FTCA) was dominant and variations in concentrations with waste age affected total estimated mass. There were six PFASs that demonstrated significantly higher concentrations in leachate from younger waste compared to older waste and six PFAS demonstrated significant variation with climate. DA - 2017/2/9/ PY - 2017/2/9/ DO - 10.1021/acs.est.6b05005 VL - 51 IS - 4 SP - 2197-2205 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.6b05005 DB - Crossref ER - TY - JOUR TI - In-Use Emissions and Estimated Impacts of Traditional, Natural- and Forced-Draft Cookstoves in Rural Malawi AU - Wathore, Roshan AU - Mortimer, Kevin AU - Grieshop, Andrew P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Emissions from traditional cooking practices in low- and middle-income countries have detrimental health and climate effects; cleaner-burning cookstoves may provide “co-benefits”. Here we assess this potential via in-home measurements of fuel-use and emissions and real-time optical properties of pollutants from traditional and alternative cookstoves in rural Malawi. Alternative cookstove models were distributed by existing initiatives and include a low-cost ceramic model, two forced-draft cookstoves (FDCS; Philips HD4012LS and ACE-1), and three institutional cookstoves. Among household cookstoves, emission factors (EF; g (kg wood)−1) were lowest for the Philips, with statistically significant reductions relative to baseline of 45% and 47% for fine particulate matter (PM2.5) and carbon monoxide (CO), respectively. The Philips was the only cookstove tested that showed significant reductions in elemental carbon (EC) emission rate. Estimated health and climate cobenefits of alternative cookstoves were smaller than predicted from laboratory tests due to the effects of real-world conditions including fuel variability and nonideal operation. For example, estimated daily PM intake and field-measurement-based global warming commitment (GWC) for the Philips FDCS were a factor of 8.6 and 2.8 times higher, respectively, than those based on lab measurements. In-field measurements provide an assessment of alternative cookstoves under real-world conditions and as such likely provide more realistic estimates of their potential health and climate benefits than laboratory tests. DA - 2017/2/7/ PY - 2017/2/7/ DO - 10.1021/acs.est.6b05557 VL - 51 IS - 3 SP - 1929-1938 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.6b05557 ER - TY - JOUR TI - Fatigue and fracture characterization of fiberglass grid-reinforced beam specimens using four-point bending notched beam fatigue test and digital image correlation technique AU - Safavizadeh, Seyed Amirshayan AU - Kim, Youngsoo Richard T2 - MATERIALS AND STRUCTURES DA - 2017/4// PY - 2017/4// DO - 10.1617/s11527-016-0980-8 VL - 50 IS - 2 SP - SN - 1871-6873 KW - Asphalt concrete KW - Grid reinforcement KW - Fatigue and fracture KW - Digital image correlation (DIC) KW - Notched beam fatigue test KW - Reflective cracking ER - TY - JOUR TI - Application of Time-Temperature Superposition Principle on Fatigue Failure Analysis of Asphalt Binder AU - Wang, Chao AU - Castrorena, Cassie AU - Zhang, Jinxi AU - Kim, Y. Richard T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - The linear amplitude sweep (LAS) test has been proposed for fatigue specifications of asphalt binders. Recently, a newly developed fatigue failure definition and energy-based failure criterion have been proposed for improving the LAS procedure and data interpreting; however, these improvements only affect LAS data conducted at a constant temperature. This paper, therefore, discusses the loading temperature effects on LAS-based binder fatigue, damage evolution, and final fatigue failure occurrence. Experimental results indicate that both damage characteristic curves (DCCs) and the failure criterion derived from the simplified-viscoelastic continuum damage (S-VECD) model are strongly affected by the testing temperature. However, the temperature shift factors determined from the dynamic shear modulus testing within the linear viscoelastic domain have been proven to be effective in eliminating the temperature influence for both fatigue DCCs and the failure criterion. The validation on binder phase demonstrates that the time-temperature superposition principle (TTSP) shift factor is only a function of temperature and is independent of strain level. TTSP application on both undamaged and damaged material behaviors is able to greatly improve the testing efficiency of the LAS-based binder fatigue characterization. DA - 2017/1// PY - 2017/1// DO - 10.1061/(asce)mt.1943-5533.0001730 VL - 29 IS - 1 SP - SN - 1943-5533 KW - Time-temperature superposition principle KW - Asphalt binder KW - Fatigue damage KW - Failure criterion ER - TY - JOUR TI - Agent-based modeling to simulate the dynamics of urban water supply: Climate, population growth, and water shortages AU - Ali, A. M. AU - Shafiee, M. E. AU - Berglund, E. Z. T2 - Sustainable Cities and Society AB - The sustainability of water resources depends on the dynamic interactions among the environmental, technological, and social characteristics of the water system and local population. These interactions can cause supply-demand imbalances at diverse temporal scales, and the response of consumers to water use regulations impacts future water availability. This research develops a dynamic modeling approach to simulate supply-demand dynamics using an agent-based modeling framework that couple models of consumers and utility managers with water system models. Households are represented as agents, and their water use behaviors are represented as rules. A water utility manager agent enacts water use restrictions, based on fluctuations in the reservoir water storage. Water balance in a reservoir is simulated, and multiple climate scenarios are used to test the sensitivity of water availability to changes in streamflow, precipitation, and temperature. The framework is applied to the water supply system in Raleigh, North Carolina to assess sustainability of drought management plans. Model accuracy is assessed using statistical metrics, and sustainability is calculated for a projected period as the satisfaction or deficit of meeting municipal demands. Multiple climate change scenarios are created by perturbing average monthly values of historical inflow, precipitation, and evapotranspiration data. Results demonstrate the use of the agent-based modeling approach to project the effectiveness of management policies and recommend drought policies for improving the sustainability of urban water resources. DA - 2017/// PY - 2017/// DO - 10.1016/j.scs.2016.10.001 VL - 28 SP - 420-434 ER - TY - JOUR TI - Why Do Construction Hazards Remain Unrecognized at the Work Interface? AU - Jeelani, Idris AU - Albert, Alex AU - Gambatese, John A. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Proper hazard recognition is an essential prerequisite to effective safety management. However, recent research has demonstrated that a large proportion of safety hazards remain unrecognized and unmanaged in complex and dynamic construction environments. Despite the importance of hazard recognition, there is a dearth of research examining why construction hazards remain unrecognized. Although few studies have examined upstream factors such as management support and experience that can indirectly influence hazard recognition levels, studies have not focused on downstream workplace factors that directly impact performance. The objective of this exploratory research was to address this knowledge gap by identifying potential impediments to hazard recognition while workers examine the work environment. In the first phase of the study, eight construction workers were engaged in a hazard recognition activity using construction case images captured from real projects within the United States. Brainstorming sessions were then conducted with the workers to identify why certain hazards remained unrecognized. In the following second phase, additional factors that impact hazard recognition and relevant industry examples were gathered by engaging an expert panel of industry professionals and academic researchers. The research process yielded 13 factors that can potentially impede thorough hazard recognition. A follow-up validation study with construction workers revealed that the most common reasons that lead to unrecognized hazards included: (1) selective attention or inattention to certain hazard types, (2) unknown potential hazard set, and (3) the perception that certain hazards impose low levels of safety risk. The findings of this research will be useful in developing effective hazard recognition methods and safety training programs that are cognizant of field-level challenges. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)co.1943-7862.0001274 VL - 143 IS - 5 SP - SN - 1943-7862 KW - Construction safety KW - Hazard recognition KW - Hazard identification KW - Safety management KW - Safety interventions KW - Safety training KW - Labor and personnel issues ER - TY - JOUR TI - Empirical measurement and improvement of hazard recognition skill AU - Albert, Alex AU - Hallowell, Matthew R. AU - Skaggs, Michael AU - Kleiner, Brian T2 - SAFETY SCIENCE AB - One explanation for high injury rates and the recent plateau in construction safety performance is that workers remain unable to recognize and manage hazards in dynamic and transient construction environments. This notion is supported by recent experimental studies, which revealed that workers are typically unable to identify and manage over 55% of hazards in their immediate work environment. These alarming discoveries prompted a series of multiple baseline experiments that tested three interventions thought to improve hazard recognition. In these studies, data were gathered from over 3000 h of field observations with 103 workers and hazard recognition performance was measured before and after each intervention was introduced. All three interventions caused improvement in overall hazard recognition performance; however, each intervention’s impact on the recognition of specific types of hazards was not evaluated. This paper addresses this knowledge gap by presenting and in-depth analysis of these data that: (1) elucidates micro-level hazard recognition across different hazard types and categories and (2) evaluates the hazard-specific impact of three recently developed interventions. The results reveal that gravity, motion, mechanical, and electrical hazards are associated with the highest baseline hazard recognition levels; whereas temperature, chemical, radiation, and biological hazards were the least recognized hazards in both the baseline and post-intervention phases. This suggests the need for targeted hazard recognition programs that focus on energy sources that are commonly missed. DA - 2017/3// PY - 2017/3// DO - 10.1016/j.ssci.2016.11.007 VL - 93 SP - 1-8 SN - 1879-1042 KW - Hazard recognition KW - Situational awareness KW - Risk KW - Construction safety KW - Worker perception ER - TY - JOUR TI - Development and Testing of a Personalized Hazard-Recognition Training Intervention AU - Jeelani, Idris AU - Albert, Alex AU - Azevedo, Roger AU - Jaselskis, Edward J. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Unrecognized or unmanaged hazards can expose workers to unanticipated safety risk and can potentially result in catastrophic safety incidents. Unfortunately, recent research has demonstrated that a large proportion of safety hazards remain unrecognized in construction workplaces. To improve hazard-recognition levels, employers adopt a variety of safety and hazard-recognition training programs. However, desirable levels of hazard recognition have not been achieved, and the expected benefits from training have not been attained. Such failure in training efforts have generally been attributed to the adoption of poor and ineffective training practices. While efforts are being undertaken to address these issues, construction research has not focused on developing or evaluating personalized training solutions that are customized to the learning needs of individual workers. To advance theory and practice, the objective of this study was to develop the first personalized training strategy targeted at improving hazard-recognition levels. The objective was accomplished by a collaborative effort involving two industry experts and three academic researchers, along with guidance from training literature. The training strategy incorporates important elements known to improve stimuli or threat detection in domains including medicine, the military, and aviation. The elements include (1) visual cues to aid systematic hazard search, (2) personalized hazard-recognition performance feedback, (3) personalized eye-tracking visual attention feedback, and (4) metacognitive prompts that trigger the adoption of remedial measures. After development, the effectiveness of the training strategy in improving hazard recognition was empirically evaluated using the nonconcurrent multiple-baseline testing approach. The findings of the study showed that the participating workers on average were able to identify only 42% of hazards prior to the introduction of the intervention; but were able to recognize 77% of hazards in the intervention phase. The findings of this study will be of interest to practicing professionals seeking to improve hazard-recognition levels within construction. DA - 2017/5// PY - 2017/5// DO - 10.1061/(asce)co.1943-7862.0001256 VL - 143 IS - 5 SP - SN - 1943-7862 KW - Construction safety KW - Safety training KW - Safety management KW - Hazard identification KW - Hazard recognition KW - Training methods KW - Personalized training KW - Safety intervention KW - Labor and personnel issues ER - TY - JOUR TI - Advanced approaches to calculate recovery length and force redistribution in semi-parallel wire cables with broken wires AU - Yu, Yujie AU - Chen, Zhihua AU - Liu, Hongbo T2 - ENGINEERING STRUCTURES AB - Two simplified models, including a theoretical approach and a finite element method (FEM) model, are proposed to calculate recovery length and study the force redistribution mechanism in a semi-parallel wire cable with broken wires. In the advanced theoretical model, the symmetrical construction and extrusion stress transfer characteristic of the semi-parallel wire cable are considered. The clench effect of the polyethylene sheath and the prestressed helical wire are considered in the derivation. The simplified FEM model can exhibit mechanical performance at both wire and cable levels. It uses helically placed beam elements to simulate twisted wires, divergently arranged rigid beam elements at the wire cross section to simulate extrusion effect, and nonlinear spring elements to consider the contact and friction between the helical wires. Results show that the recovery length is influenced by the compaction effect of wrapped sheath, as well as the twist angle and position of the broken wire. Under the symmetrical break condition, the recovery lengths calculated using the two methods are in a good agreement with each other, and force redistribution mainly results from the friction effect. Under the asymmetrical break condition, however, force redistribution is dominated by the induced unbalanced moment. DA - 2017/1/15/ PY - 2017/1/15/ DO - 10.1016/j.engstruct.2016.10.017 VL - 131 SP - 44-56 SN - 1873-7323 KW - Semi-parallel wire cable KW - Recovery length KW - Wire force redistribution KW - Theoretical method KW - Nonlinear spring KW - Finite element method ER - TY - JOUR TI - A new approach to understand metro operation safety by exploring metro operation hazard network (MOHN) AU - Li, Qiming AU - Song, Liangliang AU - List, George F. AU - Deng, Yongliang AU - Zhou, Zhipeng AU - Liu, Ping T2 - SAFETY SCIENCE AB - Numerous metro accidents expose the vulnerability of metro system. As cities are rapidly building and expanding metro systems, it is essential to thoroughly explore the nature of metro operation safety. Metro accidents can be regarded as an emergent property that arises from the unusual interactions of system components. These interactions could give rise to the phenomenon that several interrelated hazards simultaneously emerge in one single accident. Understanding these interrelations among hazards is indispensable to study metro operation safety. From this standpoint, 28 hazards and 48 interrelations among hazards were identified from 134 accidents and expert interviews, which were the foundation of establishing metro operation hazard network (MOHN). Whereby complex network theory, seven parameters were applied to further reveal the structural properties of MOHN. The results indicate that the MOHN is a scale-free network for the cumulative degree distribution obeys power-law distribution. The scale-free property of MOHN is indicative of its robustness to random attacks and its vulnerability to deliberate attacks. Nichetargeting controlling hazards of high degrees and betweenness centrality can significantly decrease the metro operation risks. Moreover, MOHN also possesses the small-world property for having a relatively high clustering coefficient and small shortest path length. This indicates that risks would be transmitted very quickly in MOHN. Secondary and derivative hazards should receive enough attention for the rapid propagation of MOHN. Revealing the inherent properties of MOHN assist in making beforehand strategies prior to metro accident and contributes to elevate system safety of metro operation. DA - 2017/3// PY - 2017/3// DO - 10.1016/j.ssci.2016.10.010 VL - 93 SP - 50-61 SN - 1879-1042 KW - Safety analysis KW - Accident analysis KW - Metro operation hazard network (MOHN) KW - Complex network theory KW - Structural characteristics ER - TY - JOUR TI - Potential of big visual data and building information modeling for construction performance analytics: An exploratory study AU - Han, Kevin K. AU - Golparvar-Fard, Mani T2 - AUTOMATION IN CONSTRUCTION AB - The ever increasing volume of visual data due to recent advances in smart devices and camera-equipped platforms provides an unprecedented opportunity to visually capture actual status of construction sites at a fraction of cost compared to other alternatives methods. Most efforts on documenting as-built status, however, stay at collecting visual data and updating BIM. Hundreds of images and videos are captured but most of them soon become useless without properly being localized with plan document and time. To take full advantage of visual data for construction performance analytics, three aspects (reliability, relevance, and speed) of capturing, analyzing, and reporting visual data are critical. This paper 1) investigates current strategies for leveraging emerging big visual data and BIM in construction performance monitoring from these three aspects, 2) characterizes gaps in knowledge via case studies and structures a road map for research in visual sensing and analytics. DA - 2017/1// PY - 2017/1// DO - 10.1016/j.autcon.2016.11.004 VL - 73 SP - 184-198 SN - 1872-7891 UR - https://doi.org/10.1016/j.autcon.2016.11.004 KW - Big visual data KW - Images KW - Videos KW - Point cloud KW - Construction progress monitoring KW - Quality control ER - TY - JOUR TI - Can Electrical Resistance Tomography be used for imaging unsaturated moisture flow in cement-based materials with discrete cracks? AU - Smyl, Danny AU - Rashetnia, Reza AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - CEMENT AND CONCRETE RESEARCH AB - Previously, it has been shown that Electrical Resistance Tomography (ERT) can be used for monitoring moisture flow in undamaged cement-based materials. In this work, we investigate whether ERT could be used for imaging three-dimensional (3D) unsaturated moisture flow in cement-based materials that contain discrete cracks. Novel computational methods based on the so-called absolute imaging framework are developed and used in ERT image reconstructions, aiming at a better tolerance of the reconstructed images with respect to the complexity of the conductivity distribution in cracked material. ERT is first tested using specimens with physically simulated cracks of known geometries, and corroborated with numerical simulations of unsaturated moisture flow. Next, specimens with loading-induced cracks are imaged; here, ERT reconstructions are evaluated qualitatively based on visual observations and known properties of unsaturated moisture flow. Results indicate that ERT is a viable method of visualizing 3D unsaturated moisture flow in cement-based materials with discrete cracks. DA - 2017/1// PY - 2017/1// DO - 10.1016/j.cemconres.2016.10.009 VL - 91 SP - 61-72 SN - 1873-3948 KW - Crack detection KW - Finite element analysis KW - Image analysis KW - Mortar KW - Transport properties ER - TY - JOUR TI - Attenuated Total Reflectance Fourier transform infrared spectroscopy for determination of Long Chain Free Fatty Acid concentration in oily wastewater using the double wavenumber extrapolation technique AU - Hao, Zisu AU - Malyala, Divya AU - Dean, Lisa AU - Ducoste, Joel T2 - TALANTA AB - Long Chain Free Fatty Acids (LCFFAs) from the hydrolysis of fat, oil and grease (FOG) are major components in the formation of insoluble saponified solids known as FOG deposits that accumulate in sewer pipes and lead to sanitary sewer overflows (SSOs). A Double Wavenumber Extrapolative Technique (DWET) was developed to simultaneously measure LCFFAs and FOG concentrations in oily wastewater suspensions. This method is based on the analysis of the Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectrum, in which the absorbance of carboxyl bond (1710cm-1) and triglyceride bond (1745cm-1) were selected as the characteristic wavenumbers for total LCFFAs and FOG, respectively. A series of experiments using pure organic samples (Oleic acid/Palmitic acid in Canola oil) were performed that showed a linear relationship between the absorption at these two wavenumbers and the total LCFFA. In addition, the DWET method was validated using GC analyses, which displayed a high degree of agreement between the two methods for simulated oily wastewater suspensions (1-35% Oleic acid in Canola oil/Peanut oil). The average determination error of the DWET approach was ~5% when the LCFFA fraction was above 10wt%, indicating that the DWET could be applied as an experimental method for the determination of both LCFFAs and FOG concentrations in oily wastewater suspensions. Potential applications of this DWET approach includes: (1) monitoring the LCFFAs and FOG concentrations in grease interceptor (GI) effluents for regulatory compliance; (2) evaluating alternative LCFFAs/FOG removal technologies; and (3) quantifying potential FOG deposit high accumulation zones in the sewer collection system. DA - 2017/4/1/ PY - 2017/4/1/ DO - 10.1016/j.talanta.2017.01.006 VL - 165 SP - 526-532 SN - 1873-3573 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85009062833&partnerID=MN8TOARS KW - Long chain free fatty acids KW - Attenuated Total Reflectance KW - Fourier transform infrared spectroscopy KW - Double wavenumber extrapolation technique KW - Sanitary sewer overflows ER - TY - JOUR TI - The effect of a roundabout corridor's design on selecting the optimal crosswalk location: A multi-objective impact analysis AU - Fernandes, P. AU - Salamati, K. AU - Rouphail, N. M. AU - Coelho, M. C. T2 - INTERNATIONAL JOURNAL OF SUSTAINABLE TRANSPORTATION AB - Crosswalks located at mid-block segment between roundabouts can provide a good balance among delay, carbon dioxide (CO2) emissions, and relative difference between vehicles and pedestrians speed. However, when considering local pollutant criteria, the optimal crosswalk location may be different to that obtained for CO2. This paper described a multi-objective analysis of pedestrian crosswalk locations, with the objectives of minimizing delay, emissions, and relative difference between vehicles and pedestrians speed. Accounting for the difference between global (e.g., CO2) and local pollutants (monoxide carbon, nitrogen oxides, and hydrocarbons) was one the main considerations of this work. Vehicle activity along with traffic and pedestrian flows data at six roundabout corridors in Portugal, one in Spain, and one in the United States were collected and extracted. A simulation environment using VISSIM, Vehicle Specific Power, and Surrogate Safety Assessment Model models was used to evaluate traffic operations along the sites. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was implemented to further search optimal crosswalk locations. The results yielded improvements to both delay and emissions by using site-optimized crosswalks. The findings also revealed that the spacing between intersections widely influenced the optimal crosswalk location along a mid-block section. If the spacing is low (<100 m), the crosswalk location will be approximately in 20%–30% of the spacing length. For spacing values between 140 and 200 m, crosswalks would be located at the midway position. When a specific pollutant criterion was considered, no significant differences were observed among optimal crosswalk data sets. DA - 2017/// PY - 2017/// DO - 10.1080/15568318.2016.1237689 VL - 11 IS - 3 SP - 206-220 SN - 1556-8334 KW - CO2 KW - crosswalks KW - local pollutants KW - multi-objective optimization KW - roundabout corridors KW - spacing ER - TY - JOUR TI - Quantifying the volatility of organic aerosol in the southeastern US AU - Saha, Provat K. AU - Khlystov, Andrey AU - Yahya, Khairunnisa AU - Zhang, Yang AU - Xu, Lu AU - Ng, Nga L. AU - Grieshop, Andrew P. T2 - Atmospheric Chemistry and Physics AB - Abstract. The volatility of organic aerosols (OA) has emerged as a property of primary importance in understanding their atmospheric life cycle, and thus abundance and transport. However, quantitative estimates of the thermodynamic (volatility, water solubility) and kinetic parameters dictating ambient-OA gas-particle partitioning, such as saturation concentrations (C∗), enthalpy of evaporation (ΔHvap), and evaporation coefficient (γe), are highly uncertain. Here, we present measurements of ambient-OA volatility at two sites in the southeastern US, one at a rural setting in Alabama dominated by biogenic volatile organic compounds (BVOCs) as part of the Southern Oxidant and Aerosol Study (SOAS) in June–July 2013, and another at a more anthropogenically influenced urban location in North Carolina during October–November 2013. These measurements applied a dual-thermodenuder (TD) system, in which temperature and residence times are varied in parallel to constrain equilibrium and kinetic aerosol volatility properties. Gas-particle partitioning parameters were determined via evaporation kinetic model fits to the dual-TD observations. OA volatility parameter values derived from both datasets were similar despite the fact that measurements were collected in distinct settings and seasons. The OA volatility distributions also did not vary dramatically over the campaign period or strongly correlate with OA components identified via positive matrix factorization of aerosol mass spectrometer data. A large portion (40–70 %) of measured ambient OA at both sites was composed of very-low-volatility organics (C∗ ≤ 0.1 µg m−3). An effective ΔHvap of bulk OA of ∼ 80–100 kJ mol−1 and a γe value of ∼ 0.5 best describe the evaporation observed in the TDs. This range of ΔHvap values is substantially higher than that typically assumed for simulating OA in atmospheric models (30–40 kJ mol−1). TD data indicate that γe is on the order of 0.1 to 0.5, indicating that repartitioning timescales for atmospheric OA are on the order of several minutes to an hour under atmospheric conditions. The OA volatility distributions resulting from fits were compared to those simulated in the Weather, Research and Forecasting model with Chemistry (WRF/Chem) with a current treatment of secondary organic aerosol (SOA) formation. The substantial fraction of low-volatility material observed in our measurements is largely missing from simulations, and OA mass concentrations are underestimated. The large discrepancies between simulations and observations indicate a need to treat low-volatility OA in atmospheric models. Volatility parameters extracted from ambient measurements enable evaluation of emerging treatments for OA (e.g., secondary OA using the volatility basis set or formed via aqueous chemistry) in atmospheric models. DA - 2017/1/11/ PY - 2017/1/11/ DO - 10.5194/acp-17-501-2017 VL - 17 IS - 1 SP - 501-520 UR - https://doi.org/10.5194/acp-17-501-2017 ER - TY - JOUR TI - New generation of precast concrete double tees reinforced with carbon-fiber-reinforced polymer grid response AU - Lunn, D. AU - Lucier, G. AU - Rizkalla, S. AU - Cleland, N. AU - Gleich, H. T2 - PCI Journal DA - 2017/// PY - 2017/// SP - 90-91 ER - TY - JOUR TI - Battle of Water Networks DMAs: Multistage Design Approach AU - Salomons, Elad AU - Skulovich, Olya AU - Ostfeld, Avi T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - Looped water distribution system (WDS) repartitioning to district metering areas (DMAs) gained popularity as an effective technique to manage the system and detect and reduce system leakages. However, to apply this method to real WDS, various system properties should be taken into account to ensure efficient water supply. The battle of water networks district meter areas (BWNDMA) is a challenging problem that requires the redesign of the E-Town city network in Colombia. The water utility is looking to repartition the network into manageable DMAs while supplying future demands, keeping minimum and maximum pressures, improving water quality, operating the network at uniform low pressures, balancing water sources, and meeting their seasonal production capabilities. The problem is stated as a multiobjective optimization problem with DMA partitioning being one of eight equal-weighted objectives. They may be reached by (1) closing, opening, or replacing existing pipes, (2) adding parallel pipes, (3) managing storage tanks, pressure valves, and flow-control valves, and (4) utilizing pumps in the dry season. With no known analytical methodology to optimize such a large mixed-integer nonlinear problem, a major difficulty is to find a feasible solution; therefore, a multistage classic engineering approach was taken. First, source allocation and general design were carried out for the operational zones. Then, tank volumes were adjusted to meet their constraints. At this stage, DMAs were introduced to meet pressure regulations. Finally, detailed design and fine-tuning of the operations were carried out. This paper describes the taken procedures and obtained results for the redesign of the E-Town network. DA - 2017/10// PY - 2017/10// DO - 10.1061/(asce)wr.1943-5452.0000830 VL - 143 IS - 10 SP - SN - 1943-5452 KW - Water distribution KW - Design KW - Optimization KW - Clustering KW - District metering areas (DMAs) ER -