TY - CONF TI - Comparison of real-world and MOVES estimated emissions for heavy-duty diesel refuse trucks AU - Sandhu, G.S. AU - Frey, H.C. AU - Bartelt-Hunt, S. AU - Jones, E. C2 - 2015/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2015/// VL - 3 SP - 1702-1711 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84983775253&partnerID=MN8TOARS ER - TY - JOUR TI - Clean Air Scientific Advisory Committee advice on the ozone standards AU - Frey, H.C. T2 - EM: Air and Waste Management Association's Magazine for Environmental Managers DA - 2015/// PY - 2015/// VL - 65 IS - May SP - 9-10 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946154078&partnerID=MN8TOARS ER - TY - JOUR TI - A scientific perspective on the challenges and opportunities for: Multipollutant approaches to air quality management AU - Frey, H.C. T2 - EM: Air and Waste Management Association's Magazine for Environmental Managers DA - 2015/// PY - 2015/// IS - January SP - 24-29 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84920474504&partnerID=MN8TOARS ER - TY - JOUR TI - Life cycle-optimization framework for photosynthetic biorefineries T2 - Abstracts of Papers of the American Chemical Society DA - 2015/// PY - 2015/// UR - https://publons.com/wos-op/publon/7119295/ ER - TY - JOUR TI - Coupling fluid dynamics with kinetic modeling to quantify the effects of photosynthetic bioreactor design and operation on yield performance T2 - Abstracts of Papers of the American Chemical Society DA - 2015/// PY - 2015/// UR - https://publons.com/wos-op/publon/7119297/ ER - TY - JOUR TI - Spatial and temporal variation in de facto wastewater reuse in drinking water systems across the U.S.A. AU - Rice, J. AU - Westerhoff, P. T2 - Environmental Science and Technology AB - De facto potable reuse occurs when treated wastewater is discharged into surface waters upstream of potable drinking water treatment plant (DWTP) intakes. Wastewater treatment plant (WWTP) discharges may pose water quality risks at the downstream DWTP, but additional flow aids in providing a reliable water supply source. In this work de facto reuse is analyzed for 2056 surface water intakes serving 1210 DWTPs across the U.S.A. that serve greater than 10 000 people, covering approximately 82% of the nation’s population. An ArcGIS model is developed to assess spatial relationships between DWTPs and WWTPs, with a python script designed to perform a network analysis by hydrologic region. A high frequency of de facto reuse occurrence was observed; 50% of the DWTP intakes are potentially impacted by upstream WWTP discharges. However, the magnitude of de facto reuse was seen to be relatively low, where 50% of the impacted intakes contained less than 1% treated municipal wastewater under average streamflow conditions. De facto reuse increased greatly under low streamflow conditions (modeled by Q95), with 32 of the 80 sites yielding at least 50% treated wastewater, this portion of the analysis is limited to sites where stream gauge data was readily available. DA - 2015/// PY - 2015/// DO - 10.1021/es5048057 VL - 49 IS - 2 SP - 982-989 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84921721434&partnerID=MN8TOARS ER - TY - JOUR TI - Extent and impacts of unplanned wastewater Reuse in US rivers AU - Rice, Jacelyn AU - Via, Steve H. AU - Westerhoff, Paul T2 - Journal - American Water Works Association AB - A recently developed watershed‐scale hydraulic model (De‐facto Reuse Incidence in our Nation's Consumptive Supply [DRINCS]) was applied to estimate municipal wastewater treatment plant (WWTP) contribution to downstream water treatment plant (WTP) influent flow. Using DRINCS and geocoded data for 14,651 WWTPs and 1,320 WTPs, the occurrence of treated municipal wastewater in drinking water supplies is geographically widespread, and its magnitude depends largely on the flow condition and size of the source river. Under average streamflow conditions in this study, the median contribution of wastewater flow to drinking water supplies was approximately 1% and increased to as much as 100% under low‐flow conditions (modeled by Q95). Wastewater contributions to nutrient and emerging contaminant loading were estimated and geospatially compared with the findings of the US Environmental Protection Agency's Unregulated Contaminant Monitoring Rule and Long Term 2 Enhanced Surface Water Treatment Rule. In turn, this analysis offers important insights into the treatment challenges facing treatment facilities across the United States. DA - 2015/// PY - 2015/// DO - 10.5942/jawwa.2015.107.0178 VL - 107 IS - 11 SP - E571-E581 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946754048&partnerID=MN8TOARS ER - TY - CONF TI - Configuration and Anchoring of Offshore Compressed Air Energy Storage (OCAES) System AU - Gabr, M.A. AU - Xiao, J. T2 - 14th International Conference on Structural & Geotechnical Engineering (ICSGE14) C2 - 2015/12// C3 - 14th International Conference on Structural & Geotechnical Engineering (ICSGE14) CY - Cairo DA - 2015/12// PY - 2015/12// ER - TY - CONF TI - Generic Speed Flow Models for Basic Freeway Segments on General Purpose and Managed Lanes AU - Aghdashi, S. AU - Rouphail, N.M. AU - Hajbabaie, A. AU - Schroeder, B.J. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - Innovative Work Zone Capacity Models from Nationwide Field and Archival Sources AU - Yoem, C. AU - Hajbabaie, A. AU - Schroeder, B.J. AU - Vaughan, C. AU - Xuan, X. AU - Rouphail, N.M. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - Freeway Reliability Scenario Generation: A Hybrid Approach AU - Aghdashi, S. AU - Hajbabaie, A. AU - Rouphail, N.M. AU - Schroeder, B.J. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - Estimating Saturation Headways at Work Zones on Urban Arterials AU - Hajbabaie, A. AU - Kim, S. AU - Schroeder, B.J. AU - Aghdashi, S. AU - Rouphail, N.M. AU - Song, T. AU - Tabrizi, K. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - Freeway Work Zone Speed Prediction from Multi-State Sensor Data AU - Hajbabaie, A. AU - Yoem, C. AU - Rouphail, N.M. AU - Rasdorf, W.J. AU - Schroeder, B.J. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - A Planning-Level Methodology for Freeway Facilities AU - Hajbabaie, A. AU - Rouphail, N.M. AU - Schroeder, B.J. AU - Dowling, R. T2 - 94th Annual Meeting of the Transportation Research Board C2 - 2015/// C3 - The 94th Annual Meeting of the Transportation Research Board CY - Washington, DC DA - 2015/// PY - 2015/1/11/ ER - TY - CONF TI - Characterization of atmospheric pressure rf discharges with aqueous plasma facing surfaces AU - Lindsay, A. AU - Byrns, B. AU - Knappe, D. AU - Shannon, S. AB - Summary form only given. Plasma modification of liquids has opened a broad range of new applications ranging from wound treatment to water purification to agricultural fertigation and herbicide. Two of the primary challenges facing systems designed to modify liquid chemistry through plasma treatment have been throughput and efficient introduction of liquid species in the active plasma region. In this presentation, we present novel pathways for both source scale up and liquid incorporation that can make plasma treatment of liquids more economically viable. C2 - 2015/// C3 - ICOPS/BEAMS 2014 - 41st IEEE International Conference on Plasma Science and the 20th International Conference on High-Power Particle Beams DA - 2015/// DO - 10.1109/PLASMA.2014.7012279 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84923050875&partnerID=MN8TOARS ER - TY - BOOK TI - Dynamic traffic flow model for travel time estimation AU - Yi, T. AU - Williams, B.M. AB - Travel time, as a fundamental measurement for intelligent transportation systems, is becoming increasingly important. Because of the wide deployment of fixed-point detectors on freeways, if travel time can be accurately estimated from point detector data, the indirect estimation method is cost-effective and widely applicable. This paper presents a modified dynamic traffic flow model for accurately estimating the travel time of freeway links under transition and congestion conditions with fixed-point detector data. The modified estimation model is based on a thorough analysis of the dynamic traffic flow model. The applications and the limitations of the model are analyzed for theory, equation derivation, and modifications. Through a simulation study and real traffic data, the (modified) dynamic models are compared according to performance measurements. A comparison of the estimated results and measurement errors shows the accuracy of the modified dynamic model for estimating the travel times of freeway links under transition and congestion traffic conditions. DA - 2015/// PY - 2015/// DO - 10.3141/2526-08 VL - 2526 SE - 70-78 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975795994&partnerID=MN8TOARS ER - TY - JOUR TI - The Challenge of Predicting the Shear Strength of Very Thick Slabs: Results Support Recommendation to Use at Least Minimum Shear Reinforcement AU - Collins, M.P. AU - Bentz, E.C. AU - Quach, P.T. AU - Proestos, G.T. T2 - Concrete International DA - 2015/11// PY - 2015/11// VL - 37 IS - 11 SP - 29–37 ER - TY - CONF TI - Predicting the Shear Strength of Concrete Structures AU - Collins, M.P. AU - Bentz, E.C. AU - Quach, P.T. AU - Fisher, A.W. AU - Proestos, G.T. T2 - New Zealand Concrete Industry Conference 2015 C2 - 2015/10/8/ C3 - Proceedings, The New Zealand Concrete Industry Conference 2015 CY - Rotorua, New Zealand DA - 2015/10/8/ PY - 2015/10/8/ ER - TY - JOUR TI - Adsorption of perfluoroalkyl acids by carbonaceous adsorbents: Effect of carbon surface chemistry AU - Zhi, Y. AU - Liu, J. T2 - Environmental Pollution AB - Adsorption by carbonaceous sorbents is among the most feasible processes to remove perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) from drinking and ground waters. However, carbon surface chemistry, which has long been recognized essential for dictating performance of such sorbents, has never been considered for PFOS and PFOA adsorption. Thus, the role of surface chemistry was systematically investigated using sorbents with a wide range in precursor material, pore structure, and surface chemistry. Sorbent surface chemistry overwhelmed physical properties in controlling the extent of uptake. The adsorption affinity was positively correlated carbon surface basicity, suggesting that high acid neutralizing or anion exchange capacity was critical for substantial uptake of PFOS and PFOA. Carbon polarity or hydrophobicity had insignificant impact on the extent of adsorption. Synthetic polymer-based Ambersorb and activated carbon fibers were more effective than activated carbon made of natural materials in removing PFOS and PFOA from aqueous solutions. DA - 2015/// PY - 2015/// DO - 10.1016/j.envpol.2015.03.019 VL - 202 SP - 168-176 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84925878084&partnerID=MN8TOARS KW - PFOS KW - PFOA KW - Activated carbon fibers KW - Carbonaceous sorbents KW - Surface chemistry KW - Basicity ER - TY - CONF TI - Coupling fluid dynamics with kinetic modeling to quantify the effects of photosynthetic bioreactor design and operation on yield performance AU - Manavi, R. AU - de los Reyes, F.L., III AU - Levis, J. AU - Ranjithan, R. AU - Ducoste, J. T2 - 249th American Chemical Society (ACS) National Meeting C2 - 2015/// CY - Denver, CO DA - 2015/// PY - 2015/3/22/ ER - TY - CONF TI - Directing Microbial Community Assembly by Deterministic Niche Differentiaion in Anaerobic Digesters AU - Wang, L. AU - Hossen, E.H. AU - Aziz, T.N. AU - Ducoste, J. AU - de los Reyes, F.L., III T2 - 88th Annual Water Environment Federation Technical Exhibition and Conference C2 - 2015/// C3 - WEFTEC 2015 : the water quality event : conference program and exhibitor guide : 88th Annual Water Environment Federation Technical Exhibition and Conference, McCormick Place, Chicago, Illinois, USA, September 26-30, 2015 CY - Chicago, IL DA - 2015/// PY - 2015/9/26/ PB - Water Environment Federation ER - TY - CONF TI - Pore Channel Tortuosity in 3D Nonwoven Structures AU - Vallabh, R. AU - Seyam, A. AU - Banks-Lee, P. AU - Ducoste, J. T2 - 6th World Conference on 3D Fabrics and their Applications C2 - 2015/5/26/ CY - Raleigh, NC DA - 2015/5/26/ PY - 2015/5/26/ ER - TY - SOUND TI - How Restaurant Kitchen Practices Influence FOG Deposit Formation in Sewer Collection Systems AU - Ducoste, J.J. DA - 2015/// PY - 2015/// ER - TY - SOUND TI - Internal and External Grease Interceptors: Challenges in the Removal of FOG Emulsions and the Impact of Food Service Establishment Kitchen Operations AU - Ducoste, J.J. DA - 2015/// PY - 2015/// M3 - Keynote ER - TY - SOUND TI - Algorithm application to identify novel regulators in the Arabidopsis thaliana iron deficiency response AU - Matthiadis, Anna AU - Koryachko, Alexandr AU - Muhammad, Durreshahwar AU - Foret, Jessica AU - Brady, Siobhan M. AU - Ducoste, Joel AU - Tuck, James AU - Williams, Cranos AU - Long, Terri A. DA - 2015/7// PY - 2015/7// ER - TY - RPRT TI - Removal of perfluoroalkyl substances by PAC adsorption and anion exchange AU - Dudley, L.A. AU - Arevalo, E.C. AU - Knappe, D.R.U. A3 - Water Research Foundation DA - 2015/// PY - 2015/// M1 - 4344 M3 - Executive summary PB - Water Research Foundation SN - 4344 ER - TY - RPRT TI - Removal of volatile organic contaminants (VOCs) from drinking water via granular activated carbon treatment AU - Summers, R.S. AU - Kempisty, D. AU - Daugherty, T. AU - Knappe, D. A3 - Water Research Foundation DA - 2015/// PY - 2015/// M1 - 4440 M3 - Final report PB - Water Research Foundation SN - 4440 ER - TY - JOUR TI - Environmental Benefits of Renewable Portfolio Standards in an Age of Coal Plant Retirements AU - Johnson, Jeremiah X. AU - Novacheck, Joshua T2 - The Electricity Journal AB - An examination of the environmental benefits of an expanded RPS in Michigan find that, with higher coal retirements, significantly more natural gas is displaced by the expanded RPS, thereby reducing the emissions mitigation potential. This illustrates how the environmental benefits of renewable energy are dependent on the system into which it is integrated. DA - 2015/10// PY - 2015/10// DO - 10.1016/j.tej.2015.09.007 VL - 28 IS - 8 SP - 59-68 J2 - The Electricity Journal LA - en OP - SN - 1040-6190 UR - http://dx.doi.org/10.1016/j.tej.2015.09.007 DB - Crossref ER - TY - CONF TI - Developing Energy and Greenhouse Gas Emission Factors for Anaerobic Digestion in U.S. EPA's Waste Reduction Model AU - Renz, B. AU - Evans, C. AU - Barlaz, M.A. AU - Levis, J.W. AU - Kollar, T. AU - Boland, C. T2 - LCA XV C2 - 2015/// CY - Vancouver, BC DA - 2015/// PY - 2015/10// ER - TY - CONF TI - Methods to measure the hydrogen sulfide production potential of sulfate-containing wastes disposed in landfills AU - Sun, W.J. AU - Sun, M. AU - Barlaz, M.A. T2 - 15th International Waste Management and Landfill Symposium C2 - 2015/// CY - S. Margherita di Pula (CA), Italy DA - 2015/// PY - 2015/10/5/ ER - TY - CONF TI - A systematic evaluation of the costs and environmental impacts associated with future municipal solid waste management AU - Levis, J. AU - Barlaz, M. AU - DeCarolis, J. AU - Ranjithan, R. T2 - 5th International Waste Management and Landfill Symposium C2 - 2015/// CY - S. Margherita di Pula (CA), Italy DA - 2015/// PY - 2015/10/5/ ER - TY - SOUND TI - Synthesis on National Water Use: Spatial Patterns and Socio-economic Controls, State of America’s Water: Present and Future AU - Arumugam, S. DA - 2015/5// PY - 2015/5// ER - TY - SOUND TI - Leonardo da Vinci: Contribution of the renaissance artist towards water management AU - Arumugam, S. DA - 2015/10// PY - 2015/10// ER - TY - SOUND TI - Synthesis on National Water Use: Spatial Patterns and Controls AU - Arumugam, S. DA - 2015/10/6/ PY - 2015/10/6/ ER - TY - CONF TI - Climate-Water-Energy Nexus: Opportunities and Challenges AU - Arumugam, S. T2 - Private Sector Partnership Forum: Climate Services and Decision Support Tools for the Energy Sector C2 - 2015/3/23/ CY - World Meteorological Organization, Geneva DA - 2015/3/23/ PY - 2015/3/23/ ER - TY - CONF TI - The role of hydroclimate and water use on freshwater sustainability over the Coterminous US AU - Arumugam, S. AU - Ruhi, A. AU - Sabo, J. AU - Sinha, T. AU - Seo, S.B. AU - Bhowmik, R.D. T2 - American Geophysical Union Fall meeting C2 - 2015/12/14/ CY - San Francisco, CA DA - 2015/12/14/ PY - 2015/12/14/ ER - TY - RPRT TI - Experimental Reservoir Storage Forecasts Utilizing Climate-Information Based Streamflow Forecasts AU - Sankarasubramanian, A. AU - Boyles, R. AU - Mazoorei, A. AU - Singh, H. A3 - NC Water Resources Research Institute DA - 2015/3// PY - 2015/3// M3 - Technical Report PB - NC Water Resources Research Institute ER - TY - JOUR TI - Evaluation of friction mechanisms and wear rates on rubber tire materials by low-cost laboratory tests AU - Vieira, T. AU - Ferreira, R.P. AU - Kuchiishi, A.K. AU - Bernucci, L.L.B. AU - Sinatora, A. T2 - Wear AB - The tire–pavement contact is part of a complex tribo-system with several variables. Once the pavement surface and the rubber tire are directly and indirectly related to transportation safety, fuel consumption, wear rate, noise generation, and others, it is possible to state that a better understanding of tribo-logical variables may provide a deeper knowledge of friction and wear phenomena. In this study, low-cost tests were carried out for the purpose of evaluating these phenomena. In addition, statistical analysis of friction and wear rates was accomplished, allowing their correlation with parameters such as surface energy and wear pattern spacing. Therefore, it was possible to validate the existence and relevance of the adhesion mechanism at friction, which is frequently neglected in the literature. It was also possible to verify the indirect methods of evaluating wear and friction performance of rubber tire materials. DA - 2015/4// PY - 2015/4// DO - 10.1016/j.wear.2015.04.001 VL - 328-329 SP - 556-562 UR - http://dx.doi.org/10.1016/j.wear.2015.04.001 KW - Polymers KW - Sliding friction KW - Contact mechanics KW - Surface analysis KW - Wear testing KW - Indentation ER - TY - JOUR TI - Using 16S metagenomics to determine microbial population shifts associated with a 336% boost in methane yield during anaerobic co-digestion of grease waste AU - Wang, Ling AU - Hossen, Elvin H AU - Aziz, Tarek N AU - Ducoste, Joel AU - Reyes, Francis L T2 - Proceedings of the Water Environment Federation DA - 2015/// PY - 2015/// VL - 2015 IS - 11 SP - 6112-6118 ER - TY - JOUR TI - Appropriate Ground Motions for Dynamic Analysis of Foundations. IFCEE/Geo-Congress 2015 Geo-Institute National Poster Competition AU - Cabas, A. AU - Rodriguez-Marek, A. DA - 2015/3/17/ PY - 2015/3/17/ ER - TY - CONF TI - VS-κ0 Correction Factors for Input Ground Motions used in Seismic Site Response Analysis AU - Cabas, A. T2 - Earthquake Engineering Research Institute (EERI) 67th Annual Meeting C2 - 2015/3/31/ C3 - Proceedings of the Earthquake Engineering Research Institute (EERI) 67th Annual Meeting 2015 CY - Boston, MA DA - 2015/3/31/ PY - 2015/3/31/ ER - TY - JOUR TI - Appearance-based material classification for monitoring of operation-level construction progress using 4D BIM and site photologs AU - Han, Kevin K. AU - Golparvar-Fard, Mani T2 - Automation in Construction AB - This paper presents a new appearance-based material classification method for monitoring construction progress deviations at the operational-level. The method leverages 4D Building Information Models (BIM) and 3D point cloud models generated from site photologs using Structure-from-Motion techniques. To initialize, a user manually assigns correspondences between the point cloud model and BIM, which automatically brings in the photos and the 4D BIM into alignment from all camera viewpoints. Through reasoning about occlusion, each BIM element is back-projected on all images that see that element. From these back-projections, several 2D patches are sampled per element and are classified into different material types. To perform material classification, the expected material type information is derived from BIM. Then the image patches are convolved with texture and color filters and their concatenated vector-quantized responses are compared with multiple discriminative material classification models that are relevant to the expected progress of that element. For each element, a quantized histogram of the observed material types is formed and the material type with the highest appearance frequency infers the appearance and thus the state of progress. To validate, four new datasets of incomplete and noisy point cloud models are introduced which are assembled from real-world construction site images and BIMs. An extended version of the Construction Material Library (CML) is also introduced for training/testing the material classifiers. The material classification shows an average accuracy of 92.4% for CML image patches of 100 × 100 pixels. The experiments on those four datasets show an accuracy of 95.9%, demonstrating the potential of appearance-based recognition method for inferring the actual state of construction progress for BIM elements. DA - 2015/5// PY - 2015/5// DO - 10.1016/J.AUTCON.2015.02.007 VL - 53 SP - 44-57 J2 - Automation in Construction LA - en OP - SN - 0926-5805 UR - http://dx.doi.org/10.1016/J.AUTCON.2015.02.007 DB - Crossref KW - Construction progress monitoring KW - Material classification KW - 3D point cloud models KW - Structure from Motion KW - Building Information Models ER - TY - CONF TI - A municipal solid waste collection model for estimating costs and emissions AU - Jaunich, M.K. AU - Levis, J.W. AU - DeCarolis, J.F. AU - Barlaz, M.A. C2 - 2015/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2015/// VL - 1 SP - 69-73 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84983078646&partnerID=MN8TOARS ER - TY - CONF TI - VS-κ Consistent Input Ground Motions for Site Response Analyses, Case Studies in Concepción and San Pedro, Chile AU - Cabas, A. AU - Rodriguez-Marek, A. AU - Montalva, G. C2 - 2015/11/15/ C3 - Proceedings of the XV Pan-American Conference on Soil Mechanics and Geotechnical Engineering, Buenos Aires DA - 2015/11/15/ ER - TY - JOUR TI - Prokaryotic Community Analysis of a Hyperalkaline Spring in the Philippines Using 16S rRNA Gene Clone Library Construction AU - Baculi, R.Q. AU - Lantican, N.B. AU - de los Reyes lll, F.L. AU - Raymundo, A.K. T2 - Philippine Journal of Science DA - 2015/6// PY - 2015/6// VL - 144 IS - 1 SP - 7–18 ER - TY - CHAP TI - Articulating resistance to nuclear power: Local tactics and strategic connections in a nuclear construction financing controversy AU - Kinsella, W.J. AU - Kelly, A.R. AU - Kittle Autry, M. T2 - Communication for the Commons Revisiting Participation and Environment A2 - Meisner, M.S. A2 - Sriskandarajah, N. A2 - Depoe, S.P. PY - 2015/// SP - 332–345 PB - International Environmental Communication Association ER - TY - JOUR TI - Perspectives on multiscale, multiphase, and multiphysics issues in bituminous materials and pavements AU - Kim, Yong-Rak AU - Underwood, B. Shane T2 - International Journal of Pavement Engineering AB - This special issue sets out to discuss various perspectives on multiscale, multiphase, and multiphysical issues in bituminous media (i.e. bituminous materials, mixtures, and pavements) by bringing together individual state-of-the-art approaches. It is meant to integrate theoretical, computational, and experimental methods along the above stated theme via significant efforts from relevant experts in our field. It is our eventual goal of this special issue to advance the current knowledge of bituminous materials/pavements with more fundamental aspects so as to improve our current practices in the materials selection, mixture design, structural design, and performance forecasting. DA - 2015/7/21/ PY - 2015/7/21/ DO - 10.1080/10298436.2015.1066008 VL - 18 IS - 9 SP - 753-753 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2015.1066008 DB - Crossref KW - Multiscale KW - multiphase KW - multiphysics KW - bituminous Materials KW - bituminous pavements ER - TY - JOUR TI - Physico-Chemical Characterization of Novel Epoxy Matrix System Reinforced with Recycled Short Milled Carbon Fibre AU - Cholake, Sagar T. AU - Moran, Grainne AU - Bai, Yu AU - Raman, R. K. Singh AU - Zhao, X. L. AU - Rizkalla, Sami AU - Bandyopadhyay, Sri T2 - Journal of Minerals and Materials Characterization and Engineering AB - As received recycled short milled carbon fiber (SMCF) reinforced diglycidal ether of bisphenol-A (DGEBA) epoxy matrix materials have been developed by ultra-sonication mixing of SMCF in epoxy then curing at room temperature for nine days. The SMCF with mean diameter 7.5 μm, and length 100 - 300 μm, was used at different loadings i.e. 1, 2, 3, 5 and 10 wt%. Elemental analysis, surface chemistry and crystallography of SMCF were examined using X-ray fluorescence, X-ray photoelectron spectroscopy and X-ray diffraction. Fourier Transform IR spectroscopy confirmed that both in unmodified and SMCF-modified epoxies, 99% curing was achieved. Surface microhardness study showed a slight increase with 5% and 10% SMCF addition. Raman study confirms no structural change in SMCF after incorporation in epoxy. Also, a numerical modelling is implemented to correlate the density of the modified epoxy and SMCF volume fraction/distribution uniformity. DA - 2015/// PY - 2015/// DO - 10.4236/jmmce.2015.35040 VL - 03 IS - 05 SP - 373-389 J2 - JMMCE OP - SN - 2327-4077 2327-4085 UR - http://dx.doi.org/10.4236/jmmce.2015.35040 DB - Crossref ER - TY - JOUR TI - Vanadium redox flow batteries to reach greenhouse gas emissions targets in an off-grid configuration AU - Arbabzadeh, Maryam AU - Johnson, Jeremiah X. AU - De Kleine, Robert AU - Keoleian, Gregory A. T2 - Applied Energy AB - Energy storage may serve as a solution to the integration challenges of high penetrations of wind, helping to reduce curtailment, provide system balancing services, and reduce emissions. This study determines the minimum cost configuration of vanadium redox flow batteries (VRFB), wind turbines, and natural gas reciprocating engines in an off-grid model. A life cycle assessment (LCA) model is developed to determine the system configuration needed to achieve a variety of CO2-eq emissions targets. The relationship between total system costs and life cycle emissions are used to optimize the generation mixes to achieve emissions targets at the least cost and determine when VRFBs are preferable over wind curtailment. Different greenhouse gas (GHG) emissions targets are defined for the off-grid system and the minimum cost resource configuration is determined to meet those targets. This approach determines when the use of VRFBs is more cost effective than wind curtailment in reaching GHG emissions targets. The research demonstrates that while incorporating energy storage consistently reduces life cycle carbon emissions, it is not cost effective to reduce curtailment except under very low emission targets (190 g of CO2-eq/kW h and less for the examined system). This suggests that “overbuilding” wind is a more viable option to reduce life cycle emissions for all but the most ambitious carbon mitigation targets. The findings show that adding VRFB as energy storage could be economically preferable only when wind curtailment exceeds 66% for the examined system. The results were most sensitive to VRFB costs, natural gas upstream emissions (e.g. methane leakage), and wind capital cost. DA - 2015/5// PY - 2015/5// DO - 10.1016/j.apenergy.2015.02.005 VL - 146 SP - 397-408 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/j.apenergy.2015.02.005 DB - Crossref KW - Energy storage KW - Vanadium redox flow battery KW - Life cycle assessment KW - Greenhouse gas emissions targets KW - Wind curtailment ER - TY - JOUR TI - Emissions Reductions from Expanding State-Level Renewable Portfolio Standards AU - Johnson, Jeremiah X. AU - Novacheck, Joshua T2 - Environmental Science & Technology AB - In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state’s imports and exports. We test this method on potential expansions to Michigan’s RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power. DA - 2015/4/17/ PY - 2015/4/17/ DO - 10.1021/es506123e VL - 49 IS - 9 SP - 5318-5325 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/es506123e DB - Crossref ER - TY - JOUR TI - The environmental and cost implications of solar energy preferences in Renewable Portfolio Standards AU - Novacheck, Joshua AU - Johnson, Jeremiah X. T2 - Energy Policy AB - Many state-level Renewable Portfolio Standards (RPS) include preferences for solar generation, with goals of increasing the generation diversity, reducing solar costs, and encouraging local solar industries. Depending on their policy design, these preferences can impact the RPS program costs and emissions reduction. This study evaluates the impact of these policies on costs and emissions, coupling an economic dispatch model with optimized renewable site selection. Three policy designs of an increased RPS in Michigan are investigated: (1) 20% Solar Carve-Out, (2) 5% Distributed Generation Solar Carve-Out, and (3) 3× Solar Multiplier. The 20% Solar Carve-Out scenario was found to increase RPS costs 28%, while the 5% Distributed Generation Solar Carve-Out increased costs by 34%. Both of these solar preferences had minimal impact on total emissions. The 3× Solar Multiplier decreases total RPS program costs by 39%, but adds less than half of the total renewable generation of the other cases, significantly increasing emissions of CO2, NOx, and SO2 relative to an RPS without the solar credit multiplier. Sensitivity analysis of the installed cost of solar and the natural gas price finds small changes in the results of the Carve-Out cases, with a larger impact on the 3× Solar Multiplier. DA - 2015/11// PY - 2015/11// DO - 10.1016/j.enpol.2015.06.039 VL - 86 SP - 250-261 J2 - Energy Policy LA - en OP - SN - 0301-4215 UR - http://dx.doi.org/10.1016/j.enpol.2015.06.039 DB - Crossref KW - Renewable Portfolio Standard KW - Economic dispatch KW - Solar energy policy KW - Renewable energy integration ER - TY - BOOK TI - Generic speed-flow models for basic freeway segments on general-purpose and managed lanes in undersaturated flow conditions AU - Aghdashi, S. AU - Rouphail, N.M. AU - Hajbabaie, A. AU - Schroeder, B.J. AB - This paper presents a generic set of undersaturated speed–flow models for basic freeway segments on general purpose and managed lanes (MLs) consistent with the Highway Capacity Manual 2010 (HCM 2010). The proposed models predict segment space mean speed under a wide set of freeway operational conditions that can affect its free-flow speed (FFS) and capacity. Furthermore, the proposed models allow quantifying the impacts of nonrecurring events, such as severe weather conditions, incidents, and work zones on the speed–flow relationship. In addition, the model allows calibration of real-world facilities through adjustments to FFS and capacity. The incorporation of analyses of reliability and active traffic and demand management in the HCM context requires a set of speed–flow models capable of accounting for the effect of nonrecurring sources of congestion. Currently, the HCM 2010 provides a set of speed–flow models to predict space mean speed and consequently other freeway performance measures. This family of equations provides a limited adjustment to FFS. With guidance from NCHRP Project 3-96, separate speed–flow models are proposed for MLs through use of a different form from that in the HCM. The proposed generic equations describing the speed–flow relationship provide consistency between speed–flow relationships of managed and general purpose lanes and can incorporate any capacity or FFS adjustments to predict segment speed under different circumstances. The proposed generic equations are wholly consistent with the speed–flow models in the HCM 2010 and predict the same speed under any flow rate. DA - 2015/// PY - 2015/// DO - 10.3141/2483-12 VL - 2483 SE - 102-110 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975744162&partnerID=MN8TOARS ER - TY - JOUR TI - Confined Flocculation of Ionic Pollutants by Poly(l-dopa)-Based Polyelectrolyte Complexes in Hydrogel Beads for Three-Dimensional, Quantitative, Efficient Water Decontamination T2 - Langmuir AB - The development of simple and recyclable adsorbents with high adsorption capacity is a technical imperative for water treatment. In this work, we have successfully developed new adsorbents for the removal of ionic pollutants from water via encapsulation of polyelectrolyte complexes (PECs) made from positively charged poly(allylamine hydrochloride) (PAH) and negatively charged poly(l-3,4-dihydroxyphenylalanine) (PDopa), obtained via the self-polymerization of l-3,4-dihydroxyphenylalanine (l-Dopa). Given the outstanding mass transport through the hydrogel host matrixes, the PDopa-PAH PEC guests loaded inside can effectively and efficiently remove various ionic pollutants, including heavy metal ions and ionic organic dyes, from water. The adsorption efficiency of the PDopa-PAH PECs can be quantitatively correlated to and tailored by the PDopa-to-PAH molar ratio. Because PDopa embodies one catechol group, one carboxyl group, and one amino group in each repeating unit, the resulting PDopa-PAH PECs exhibit the largest capacity of adsorption of heavy metal ions compared to available adsorbents. Because both PDopa and PAH are pH-sensitive, the PDopa-PAH PEC-loaded agarose hydrogel beads can be easily and completely recovered after the adsorption of ionic pollutants by adjusting the pH of the surrounding media. The present strategy is similar to the conventional process of using PECs to flocculate ionic pollutants from water, while in our system flocculation is confined to the agarose hydrogel beads, thus allowing easy separation of the resulting adsorbents from water. DA - 2015/6/16/ PY - 2015/6/16/ DO - 10.1021/acs.langmuir.5b01084 UR - http://dx.doi.org/10.1021/acs.langmuir.5b01084 ER - TY - CONF TI - Drained Shear Strength of MICP Sand at Varying Cementation Levels AU - Feng, K. AU - Montoya, B. M. T2 - IFCEE 2015 AB - Microbial induced calcite precipitation (MICP) is a novel ground improvement method to increase strength and stiffness of sand using natural biogeochemical processes. Cementation level and confining pressure are two important factors that control the behavior of MICP sand. The static mechanical responses of MICP cemented sand are systematically investigated using four cementation levels (untreated, lightly treated, moderately treated, and heavily treated) and three levels of confining pressure (100 kPa, 200 kPa, and 400 kPa). The experimental results indicate that the improvement in shear strength parameters is dependent on the level of cementation under peak and residual states. Uniformity of MICP cementation in laboratory scale is also discussed. When comparing the response of MICP sand with naturally cemented sand and artificially treated sand with portland cement, the MICP cemented sand is observed to better capture the small strain stiffness of the naturally cemented soil. C2 - 2015/3/17/ C3 - IFCEE 2015 DA - 2015/3/17/ DO - 10.1061/9780784479087.208 PB - American Society of Civil Engineers SN - 9780784479087 UR - http://dx.doi.org/10.1061/9780784479087.208 DB - Crossref ER - TY - JOUR TI - Capturing the Return on Investment of All-In Building Information Modeling: Structured Approach AU - Stowe, Ken AU - Zhang, Sijie AU - Teizer, Jochen AU - Jaselskis, Edward J. T2 - Practice Periodical on Structural Design and Construction AB - Many construction firms now use building information modeling (BIM), and champions at those firms know that BIM delivers significant benefits. Whether the benefits are significant enough to merit deeper BIM adoption is unclear at this point in the architecture/engineering/construction (A/E/C) industry. To investigate this problem, the lead author conducted more than 51 workshops worldwide with practitioners who presently use BIM and elicited cost and benefit data from them using actual project case study data. The workshops provided a structured approach to capturing the true benefits of BIM in the A/E/C community. Through the workshop case study approach, 19 of the most impactful benefits that accompany an integrated, all-in approach to BIM were identified. This paper describes these benefits in detail, as well as the current limitations, and sheds light on attributes of BIM in the near future. The findings have the potential to help the A/E/C industry make informed decisions to maximize returns on BIM investment and establish realistic success targets and measures. DA - 2015/2// PY - 2015/2// DO - 10.1061/(ASCE)SC.1943-5576.0000221 VL - 20 IS - 1 SP - 04014027 J2 - Pract. Period. Struct. Des. Constr. LA - en OP - SN - 1084-0680 1943-5576 UR - http://dx.doi.org/10.1061/(ASCE)SC.1943-5576.0000221 DB - Crossref ER - TY - JOUR TI - Characterizing corridor-level travel time distributions based on stochastic flows and segment capacities AU - Lei, Hao AU - Zhou, Xuesong AU - List, George F. AU - Taylor, Jeffrey T2 - Cogent Engineering AB - Trip travel time reliability is an important measure of transportation system performance and a key factor affecting travelers’ choices. This paper explores a method for estimating travel time distributions for corridors that contain multiple bottlenecks. A set of analytical equations are used to calculate the number of queued vehicles ahead of a probe vehicle and further capture many important factors affecting travel times: the prevailing congestion level, queue discharge rates at the bottlenecks, and flow rates associated with merges and diverges. Based on multiple random scenarios and a vector of arrival times, the lane-by-lane delay at each bottleneck along the corridor is recursively estimated to produce a route-level travel time distribution. The model incorporates stochastic variations of bottleneck capacity and demand and explains the travel time correlations between sequential links. Its data needs are the entering and exiting flow rates and a sense of the lane-by-lane distribution of traffic at each bottleneck. A detailed vehicle trajectory data-set from the Next Generation SIMulation (NGSIM) project has been used to verify that the estimated distributions are valid, and the sources of estimation error are examined. DA - 2015/1/9/ PY - 2015/1/9/ DO - 10.1080/23311916.2014.990672 VL - 2 IS - 1 J2 - Cogent Engineering LA - en OP - SN - 2331-1916 UR - http://dx.doi.org/10.1080/23311916.2014.990672 DB - Crossref KW - travel time reliability KW - stochastic capacity KW - stochastic demand KW - queue model ER - TY - JOUR TI - Use of basalt fibers for concrete structures AU - High, Cory AU - Seliem, Hatem M. AU - El-Safty, Adel AU - Rizkalla, Sami H. T2 - Construction and Building Materials AB - This study investigated the use of basalt fiber bars as flexural reinforcement for concrete members and the use of chopped basalt fibers as an additive to enhance the mechanical properties of concrete. The material characteristics and development length of two commercially-available basalt fiber bars were evaluated. Test results indicate that flexural design of concrete members reinforced with basalt fiber bars should ensure compression failure and satisfying the serviceability requirements. ACI 440.1R-06 accurately predicts the flexural capacity of members reinforced with basalt bars, but it significantly underestimates the deflection at service load level. Use of chopped basalt fibers had little effect on the concrete compressive strength; however, significantly enhanced its flexural modulus. DA - 2015/10// PY - 2015/10// DO - 10.1016/J.CONBUILDMAT.2015.07.138 VL - 96 SP - 37-46 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/J.CONBUILDMAT.2015.07.138 DB - Crossref KW - Fibers KW - Basalt KW - Fiber-reinforced concrete KW - Bond KW - Flexure KW - Average residual strength ER - TY - CONF TI - Agent-Based Modeling to Simulate Demand Management Strategies for Shared Groundwater Resources AU - Al-Amin, Shams AU - Berglund, Emily Z. AU - Larson, Kelli L. T2 - World Environmental and Water Resources Congress 2015 AB - Growing population centers in the arid southwest increase the demand for water, which is typically met through increased groundwater withdrawals. Hydro-climatic extremes due to climate change may also increase demands and decrease the replenishment of groundwater supply. Groundwater aquifers typically cross watershed, municipal, and management boundaries, and as a result, multiple diverse agencies manage a shared resource. Municipalities and management districts define individual demand management strategies that adapt water consumption to falling groundwater levels. The interactions among governing agencies, consumers, and the environment influence the performance of local management strategies and the availability of regional groundwater resources. This research develops an agent-based modeling (ABM) framework to analyze the dynamic interactions among changing water demands and limited groundwater resources under the stresses of population growth and climate change scenarios. Households are initialized as agents with properties and attributes to define indoor water use, outdoor water use, and water use reduction. Policy-maker agents are encoded to represent governing agencies that mandate or encourage water use restrictions. Demand management strategies are simulated as the response of a policy-maker agent to groundwater levels, safe yield, and climate variables. The framework is applied for municipalities located in the Verde River Basin, Arizona that withdraw groundwater from the Verde Formation-Basin Fill-Carbonate aquifer system. The effects of management strategies on water savings and basin-wide groundwater levels are explored, based on water use demands and reductions in different sectors of municipal water use. Insights gained through this simulation study can be used to guide groundwater policy-making under changing hydro-climatic scenarios for a long-term planning horizon. C2 - 2015/5/14/ C3 - World Environmental and Water Resources Congress 2015 DA - 2015/5/14/ DO - 10.1061/9780784479162.203 PB - American Society of Civil Engineers SN - 9780784479162 UR - http://dx.doi.org/10.1061/9780784479162.203 DB - Crossref ER - TY - CONF TI - Results of a National Survey about the Public Acceptability of Reclaimed Water AU - Garcia-Cuerva, Laura AU - Schmidt, Michelle AU - Berglund, Emily Z. AU - Binder, Andrew R. T2 - World Environmental and Water Resources Congress 2015 AB - Reclaimed water programs treat wastewater to remove hazardous compounds, pathogens, and organic matter and provide reclaimed water for non-potable applications. Reusing water may significantly reduce demands on freshwater resources and provide sustainable water management strategies. Though guidelines for reclaimed water are highly regulated, public acceptability has historically hindered the implementation of successful reclaimed water systems. The public generally opposes the use of reclaimed water due to the “yuck factor”, which is the instinctive disgust associated with the idea of recycling sewage and the fear that exposure to reclaimed water is unsafe. Public acceptability has been shown to vary significantly for diverse reclaimed water applications, and support for reclaimed water applications may vary based on the level of contact that consumers have with the recycled water. Opposition towards using reclaimed water in personal residences may be a major barrier in distributing reclaimed water to residential consumers, and the adoption of reclaimed water technologies by consumers can affect network performance and potable water savings. This paper reports the results of an extensive survey that was conducted to evaluate the potential acceptability of reclaimed water use. A total of 2800 respondents across the U.S. participated in the survey, and survey results demonstrate the types of reclaimed water applications that are most acceptable. In addition, climate, economic, and demographic factors affect the perceived acceptability of reclaimed water. Results and conclusions of the survey can provide insight for implementing successful reclaimed water programs. C2 - 2015/5/14/ C3 - World Environmental and Water Resources Congress 2015 DA - 2015/5/14/ DO - 10.1061/9780784479162.121 PB - American Society of Civil Engineers SN - 9780784479162 UR - http://dx.doi.org/10.1061/9780784479162.121 DB - Crossref ER - TY - JOUR TI - Biopolymers: Multidimensional Vascularized Polymers using Degradable Sacrificial Templates (Adv. Funct. Mater. 7/2015) AU - Gergely, Ryan C. R. AU - Pety, Stephen J. AU - Krull, Brett P. AU - Patrick, Jason F. AU - Doan, Thu Q. AU - Coppola, Anthony M. AU - Thakre, Piyush R. AU - Sottos, Nancy R. AU - Moore, Jeffrey S. AU - White, Scott R. T2 - Advanced Functional Materials AB - S. R. White and co-workers develop sacrificial templates of 0D to 3D used to create vascular and porous architectures in polymers on page 1043. Embedded sacrificial templates are removed using a thermal treatment process, VaSC, leaving behind an inverse replica. This reconstruction of microCT imaging shows 3D channel architecture created using a 3D printed sacrificial template and the pressure distribution of fluid flow. DA - 2015/2// PY - 2015/2// DO - 10.1002/ADFM.201570048 VL - 25 IS - 7 SP - 1042-1042 J2 - Adv. Funct. Mater. LA - en OP - SN - 1616-301X UR - http://dx.doi.org/10.1002/ADFM.201570048 DB - Crossref ER - TY - JOUR TI - Leachate Quality Monitoring from Conventional, Retrofit, and Bio-Reactor Landfill Cells AU - Abichou, Tarek AU - Barlaz, Morton A. AU - Goldsmith, Doug AU - Green, Roger AU - Hater, Gary T2 - Journal of Hazardous, Toxic, and Radioactive Waste AB - The recirculation of leachate is a common strategy to accelerate the decomposition of municipal solid waste in landfills. In this study, leachates from a conventional landfill cell without supplemental liquid addition (Control cell), a new landfill area that had a piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for the recirculation of liquids (Retrofit cell) were monitored at the outer loop landfill bioreactor (OLLB) in Louisville, Kentucky. In general, leachates from the Retrofit cells were statistically different from leachates from the As-Built and Control cells. This is likely because the waste in Retrofit cells was about 6 years old when liquids were first introduced and the waste had already reached a more mature state prior to supplemental liquids addition. Based on time series data, the Retrofit cells, which received nitrified leachate, did not show signs of accelerated waste decomposition based on the leachate chemistry. In contrast, there were significant differences in parameters affected by waste biodegradation [temperature, pH, biological oxygen demand (BOD), chemical oxygen demand (COD), volatile organic acid (VOA), total organic carbon (TOC)] between the As-Built and Control cells, suggesting that the introduction of liquids accelerated waste decomposition in the As-Built cells. Trends were generally similar in the As-Built cells compared to the Control cells, even though concentrations of some parameters were higher in the As-Built cells. The elevated temperature in the As-Built cells suggests more active decomposition. DA - 2015/10// PY - 2015/10// DO - 10.1061/(asce)hz.2153-5515.0000288 VL - 19 IS - 4 SP - 04015009 J2 - J. Hazard. Toxic Radioact. Waste LA - en OP - SN - 2153-5493 2153-5515 UR - http://dx.doi.org/10.1061/(asce)hz.2153-5515.0000288 DB - Crossref ER - TY - JOUR TI - Evaluation of Multiple Stress Creep and Recovery (MSCR) Data for Arizona AU - Stevens, R. AU - Stempihar, J. AU - Underwood, B.S. AU - Pal, D. T2 - International Journal of Pavement Research and Technology DA - 2015/// PY - 2015/// DO - 10.6135/ijprt.org.tw/2015.8(4).337 VL - 8 IS - 5 SP - 337–345 ER - TY - JOUR TI - Testing and Modeling of Fine Aggregate Matrix and Its Relationship to Asphalt Concrete Mix AU - Gudipudi, Padmini AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The study of the fundamental properties of asphalt concrete (AC) can be used to improve and maximize the performance potential of these materials. In this paper, the fundamental approach is examined by coupling its essential hypothesis to an investigation of AC across multiple length scales. Asphalt and aggregate materials from the state of Arizona were used to prepare fine aggregate matrix (FAM) and AC samples. Laboratory tests on these materials were conducted to investigate the modulus and damage characteristics for two binder types. A comparison of mechanical response across length scales is not new, and the unique element of this study is testing both materials in the axial direction (tension–compression) for both modulus and fatigue. A strong relationship between these two materials was observed; this relationship suggests that tests on FAM samples can provide much needed insight in understanding the behavior of AC for various conditions. The study also investigated upscaling of the FAM properties to those of the AC mixture through a homogenized continua approach. Multiple upscale models were evaluated in this upscaling process, but the chosen method produced the best overall match to experimental data. The findings from this modeling effort were also used to upscale the behaviors of FAM to identify the fatigue characteristics of AC mixtures and evaluate the long-term performance of the material. DA - 2015/1// PY - 2015/1// DO - 10.3141/2507-13 VL - 2507 IS - 1 SP - 120-127 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2507-13 DB - Crossref ER - TY - CONF TI - Seismic assessment of the full scale four storey E-Defense rocking shear wall Shake Table Test AU - Proestos, G.T. AU - Aghabeigi, H. AU - Calvi, P.M. C2 - 2015/// C3 - COMPDYN 2015 - 5th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering DA - 2015/// SP - 3117-3126 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84942287992&partnerID=MN8TOARS ER - TY - JOUR TI - Role of multimodel combination and data assimilation in improving streamflow prediction over multiple time scales AU - Li, Weihua AU - Sankarasubramanian, A. AU - Ranjithan, R. S. AU - Sinha, Tushar T2 - Stochastic Environmental Research and Risk Assessment DA - 2015/9/24/ PY - 2015/9/24/ DO - 10.1007/s00477-015-1158-6 VL - 30 IS - 8 SP - 2255-2269 J2 - Stoch Environ Res Risk Assess LA - en OP - SN - 1436-3240 1436-3259 UR - http://dx.doi.org/10.1007/s00477-015-1158-6 DB - Crossref ER - TY - JOUR TI - Instructional Design for Stem-Based Collaborative, Colocated Classroom Composition AU - Mehlenbacher, Brad AU - Autry, Meagan Kittle AU - Kelly, Ashley Rose T2 - IEEE Transactions on Professional Communication AB - Research problem: Our study focuses on how students collaborate online to produce specific written genres, using particular collaborative technologies to work together productively, and how instructor feedback and student perspectives on collaborative work influence those activities in online classrooms. Research questions: When composing using collaborative web-based writing applications, do students focus primarily on the interface or the text space? What kinds of expectations about collaborative writing do students bring to the interface and text space? To what extent can we characterize students' acknowledgement of a third space, what we have identified as “communicative interaction?” Literature review: Workplace collaboration is important because organizations increasingly demand effective collaborators, team members, and team leaders, and technologies for sharing, cobuilding, and feedback are readily available to support these activities. Student preparation for workplace collaboration is important because students struggle when they are asked to write together, particularly when the collaborative process involves new technologies, and yet knowledge of collaborative writing strategies and experience with collaborative technologies, such as Google Docs, are the very competencies that organizations expect of them. Methodology: Thirteen groups of 3 to 4 technical writing students and science communication students enrolled in online professional writing courses at a major research university wrote feature specifications and reports on the globalization of the sciences, respectively, using Google Docs within Google Drive. Sixteen of 37 students responded to a set of questions asking them to reflect on their experiences working collaboratively, learning new genres, using the collaborative environment, and revising with instructor feedback. Results and conclusions: We found that students struggled most with adapting their already established collaborative strategies grounded in face-to-face learning situations to an online learning environment, where they felt their means of communication and expression were limited. The results suggest that effective collaborative experiences, properly executed, represent a repertoire of competencies that go well beyond only technical considerations, such as being able to effectively assign roles, set milestones, and navigate the numerous tasks and processes of writing as a team. The small number of students and the single instructor with her own particular feedback style limit the study. Future research includes looking at how different feedback styles influence student collaborative writing. DA - 2015/12// PY - 2015/12// DO - 10.1109/tpc.2016.2517538 VL - 58 IS - 4 SP - 396-409 J2 - IEEE Trans. Profess. Commun. OP - SN - 0361-1434 1558-1500 UR - http://dx.doi.org/10.1109/tpc.2016.2517538 DB - Crossref KW - Collaboration KW - computer-mediated communication KW - instructional design KW - online learning environments KW - Science, Technology, Engineering and Mathematics (STEM) KW - writing feedback ER - TY - THES TI - Understanding Sources and Determinants of Fecal Contamination of Water, Hands, Food, and Household Floors in Low-income Countries AU - Harris, Angela R DA - 2015/// PY - 2015/// PB - Stanford University ER - TY - JOUR TI - Genotypic and phenotypic characterization of Escherichia coli isolates from feces, hands, and soils in rural Bangladesh via the Colilert Quanti-Tray system AU - Julian, Timothy R AU - Islam, M Aminul AU - Pickering, Amy J AU - Roy, Subarna AU - Fuhrmeister, Erica R AU - Ercumen, Ayse AU - Harris, Angela AU - Bishai, Jason AU - Schwab, Kellogg J T2 - Appl. Environ. Microbiol. DA - 2015/// PY - 2015/// VL - 81 IS - 5 SP - 1735-1743 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 - 2015/9/29/ PY - 2015/9/29/ DO - 10.1080/10298436.2015.1066003 VL - 18 IS - 9 SP - 798-810 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2015.1066003 DB - Crossref KW - Asphalt mastic KW - reclaimed asphalt pavement KW - micromechanics KW - blending KW - composite ER - TY - JOUR TI - Twelve Principles for Green Energy Storage in Grid Applications AU - Arbabzadeh, Maryam AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. AU - Rasmussen, Paul G. AU - Thompson, Levi T. T2 - Environmental Science & Technology AB - The introduction of energy storage technologies to the grid could enable greater integration of renewables, improve system resilience and reliability, and offer cost effective alternatives to transmission and distribution upgrades. The integration of energy storage systems into the electrical grid can lead to different environmental outcomes based on the grid application, the existing generation mix, and the demand. Given this complexity, a framework is needed to systematically inform design and technology selection about the environmental impacts that emerge when considering energy storage options to improve sustainability performance of the grid. To achieve this, 12 fundamental principles specific to the design and grid application of energy storage systems are developed to inform policy makers, designers, and operators. The principles are grouped into three categories: (1) system integration for grid applications, (2) the maintenance and operation of energy storage, and (3) the design of energy storage systems. We illustrate the application of each principle through examples published in the academic literature, illustrative calculations, and a case study with an off-grid application of vanadium redox flow batteries (VRFBs). In addition, trade-offs that can emerge between principles are highlighted. DA - 2015/12/23/ PY - 2015/12/23/ DO - 10.1021/acs.est.5b03867 VL - 50 IS - 2 SP - 1046-1055 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.5b03867 DB - Crossref ER - TY - CONF TI - Using 16s metagenomics to determine microbial population shifts associated with a 336% boost in methane yield during anaerobic co-digestion of grease waste AU - Wang, L. AU - Hossen, E.H. AU - Aziz, T.N. AU - Ducoste, J. AU - Reyes, F.L. C2 - 2015/// C3 - 88th Annual Water Environment Federation Technical Exhibition and Conference, WEFTEC 2015 DA - 2015/// VL - 8 SP - 6112-6118 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84992022948&partnerID=MN8TOARS ER - TY - JOUR TI - Computational approaches to identify regulators of plant stress response using high-throughput gene expression data AU - Koryachko, Alexandr AU - Matthiadis, Anna AU - Ducoste, Joel J. AU - Tuck, James AU - Long, Terri A. AU - Williams, Cranos T2 - Current Plant Biology AB - Insight into biological stress regulatory pathways can be derived from high-throughput transcriptomic data using computational algorithms. These algorithms can be integrated into a computational approach to provide specific testable predictions that answer biological questions of interest. This review conceptually organizes a wide variety of developed algorithms into a classification system based on desired type of output predictions. This classification is then used as a structure to describe completed approaches in the literature, with a focus on project goals, overall path of implemented algorithms, and biological insight gained. These algorithms and approaches are introduced mainly in the context of research on the model plant species Arabidopsis thaliana under stress conditions, though the nature of computational techniques makes these approaches easily applicable to a wide range of species, data types, and conditions. DA - 2015/9// PY - 2015/9// DO - 10.1016/j.cpb.2015.04.001 VL - 3-4 SP - 20-29 J2 - Current Plant Biology LA - en OP - SN - 2214-6628 UR - http://dx.doi.org/10.1016/j.cpb.2015.04.001 DB - Crossref KW - Stress response KW - Transcription factors KW - Gene regulatory networks KW - Algorithms KW - Arabidopsis thaliana ER - TY - CONF TI - SS Marine Renewable Energy – Ocean Current Turbine Mooring Considerations AU - VanZwieten, J.H. AU - Baxley, W.E. AU - Alsenas, G.M. AU - Meyer, I. AU - Muglia, M. AU - Lowcher, C. AU - Bane, J. AU - Gabr, M. AU - He, R. AU - Hudon, T. AU - Stevens, R. AU - Duerr, A.E.S. AB - Abstract To assist in the development of mooring and foundation solutions for ocean current based electricity production, an overview of the resource and seafloor characteristics in three potential power production regions are presented. These regions are offshore Florida USA, North Carolina USA, and South Africa. Maximum measured flow speed off both the USA and South Africa were around 3.0 m/s and maximum temporally averaged energy densities were between 2.0 - 3.0 kW/m2. Water depths at considered locations range from 60-400 m, and bottom type varies greatly. Most evaluated locations contain occasional flow reversals and occasions when current speed approached 0.0 m/s (only locations near the core of the Gulfstream off SE Florida did not measure either event). While low current events are undesirable from energy production and mooring design perspectives, they might provide unique opportunities to install or maintain equipment. C2 - 2015/// C3 - Offshore Technology Conference DA - 2015/// DO - 10.4043/25965-ms PB - Society of Petroleum Engineers (SPE) ER - TY - JOUR TI - Plastic Flow of Sand and Pullout Capacity of Suction Caissons AU - Gabr, M. A. AU - Xiao, J. AU - Rahman, M. S. T2 - Journal of Geotechnical and Geoenvironmental Engineering AB - Previous articleNext article Free accessTechnical Breakthrough AbstractsMay 4, 2015Plastic Flow of Sand and Pullout Capacity of Suction CaissonsAuthors: M. A. Gabr, Ph.D., F.ASCE [email protected], J. Xiao [email protected], and M. S. Rahman, Ph.D. [email protected]Author AffiliationsPublication: Journal of Geotechnical and Geoenvironmental EngineeringVolume 141, Issue 8https://doi.org/10.1061/(ASCE)GT.1943-5606.0001331 PDF DA - 2015/8// PY - 2015/8// DO - 10.1061/(asce)gt.1943-5606.0001331 VL - 141 IS - 8 SP - 02815002 J2 - J. Geotech. Geoenviron. Eng. LA - en OP - SN - 1090-0241 1943-5606 UR - http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0001331 DB - Crossref ER - TY - JOUR TI - Experimental Evaluation of Recycled Aggregate Porous Concrete Piles for Soft Ground Improvement AU - You, Seung-Kyong AU - Lee, Jintae AU - Gabr, Mohammed A. T2 - Marine Georesources & Geotechnology AB - The use of sand compaction pile or gravel compaction pile is nowadays a common approach for soft ground improvement. In this article, a recycled aggregate porous concrete pile has been developed by replacing natural aggregates with recycled aggregates to overcome issues related to bulging failure or reduced section geometries. Such issues may arise during installation and during the early stages of operation. In addition, the proposed approach utilizes recycled aggregates instead of natural materials. To investigate the applicability of the recycled aggregate porous concrete pile method as a ground improvement technique, a series of laboratory model consolidation tests was performed on soft clay soil reinforced with sand compaction pile, gravel compaction pile, and recycled aggregate porous concrete pile, respectively. The results indicated that the settlement reduction effect of recycled aggregate porous concrete pile was significantly higher than the sand compaction pile and gravel compaction pile methods. The stress sharing ratio from the experimental program showed good agreement with those calculated by elasticity theory. Comparative analyses of the recycled aggregate porous concrete pile versus sand compaction pile and gravel compaction pile approaches, under the same replacement area ratio and surcharge pressure, showed significantly improved consolidation time, settlement reduction, and stress sharing effect. DA - 2015/8/14/ PY - 2015/8/14/ DO - 10.1080/1064119x.2015.1076913 VL - 34 IS - 8 SP - 712-720 J2 - Marine Georesources & Geotechnology LA - en OP - SN - 1064-119X 1521-0618 UR - http://dx.doi.org/10.1080/1064119X.2015.1076913 DB - Crossref KW - compaction pile KW - recycled aggregate porous concrete pile KW - soft ground improvement ER - TY - JOUR TI - A program for simultaneous network signal timing optimization and traffic assignment AU - Hajbabaie, Ali AU - Benekohal, Rahim F T2 - IEEE Transactions on Intelligent Transportation Systems AB - This study formulates a program for simultaneous traffic signal optimization and system optimal traffic assignment for urban transportation networks with added degree of realism. The formulation presents a new objective function, i.e., weighted trip maximization, and explicit constraints that are specifically designed to address oversaturated conditions. This formulation improves system-wise performance while locally prevents queue spillovers, de-facto reds, and gridlocks. A meta-heuristic algorithm is developed that incorporates microscopic traffic flow models and system optimal traffic assignment in genetic algorithms. This solution technique efficiently optimizes signal timing parameters, at the same time solves system optimal traffic assignment, and accounts for oversaturated conditions and different driver's behaviors. This study also proposes a framework to calculate an upper bound on the value of the objective function by solving the problem while several constraints (i.e., network loading and traffic assignment) are relaxed. An empirical case study for a portion of downtown Springfield, Illinois has been conducted under four demand patterns. Findings indicate that our solution approach can solve the problem effectively. Several managerial insights have also been drawn. DA - 2015/// PY - 2015/// DO - 10.1109/TITS.2015.2413360 VL - 16 IS - 5 SP - 2573-2586 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84959530041&partnerID=MN8TOARS KW - Network signal timing optimization KW - traffic assignment KW - genetic algorithms KW - weighted trip maximization KW - objective function upper-bound KW - system optimal ER - TY - JOUR TI - Unblocking occluded genres in graduate writing: Thesis and Dissertation Support Services at NC State University AU - Kittle Autry, M. AU - Carter, M. T2 - Composition Forum DA - 2015/4/1/ PY - 2015/4/1/ VL - 31 UR - http://compositionforum.com/issue/31/north-carolina-state.php N1 - Available online at RN - Available online at ER - TY - JOUR TI - The value of streamflow data in improving TSS predictions - Bayesian multi-objective calibration AU - Sikorska, A.E. AU - Giudice, D. Del AU - Banasik, K. AU - Rieckermann, J. T2 - Journal of Hydrology AB - The concentration of total suspended solids (TSS) in surface waters is a commonly used indicator of water quality impairments. Its accurate prediction remains, however, problematic because: (i) TSS build-up, erosion, and wash-off are not easily identifiable; (ii) calibrating a TSS model requires observations of sediment loads, which are rare, and streamflow observations to calculate concentrations; and (iii) predicted TSS usually deviate systematically from observations, an effect which is commonly neglected. Ignoring systematic errors during calibration can lead to overconfident (i.e. unreliable) uncertainty estimates during predictions. In this paper, we therefore investigate whether a statistical description of systematic model errors makes it possible to generate reliable predictions for TSS. In addition, we explore how the reliability of TSS predictions increases when streamflow data are additionally used in model calibration. A key aspect of our study is that we use a Bayesian multi-output calibration and a novel autoregressive error model, which describes the model predictive error as a sum of independent random noise and autocorrelated bias. Our results show that using a statistical description of model bias provides more reliable uncertainty estimates of TSS than before and including streamflow data into calibration makes TSS predictions more precise. For a case study of a small ungauged catchment, this improvement was as much as 15%. Our approach can be easily implemented for other water quality variables which are dependent on streamflow. DA - 2015/9// PY - 2015/9// DO - 10.1016/j.jhydrol.2015.09.051 VL - 9 SP - 241-254 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84943800958&partnerID=MN8TOARS KW - TSS KW - Uncertainty analysis KW - Bayesian inference KW - Multivariate calibration KW - Model bias KW - Autocorrelated errors ER - TY - JOUR TI - Model bias and complexity – Understanding the effects of structural deficits and input errors on runoff predictions AU - Giudice, D. Del AU - Reichert, P. AU - Bareš, V. AU - Albert, C. AU - Rieckermann, J. T2 - Environmental Modelling & Software AB - Oversimplified models and erroneous inputs play a significant role in impairing environmental predictions. To assess the contribution of these errors to model uncertainties is still challenging. Our objective is to understand the effect of model complexity on systematic modeling errors. Our method consists of formulating alternative models with increasing detail and flexibility and describing their systematic deviations by an autoregressive bias process. We test the approach in an urban catchment with five drainage models. Our results show that a single bias description produces reliable predictions for all models. The bias decreases with increasing model complexity and then stabilizes. The bias decline can be associated with reduced structural deficits, while the remaining bias is probably dominated by input errors. Combining a bias description with a multimodel comparison is an effective way to assess the influence of structural and rainfall errors on flow forecasts. DA - 2015/2// PY - 2015/2// DO - 10.1016/j.envsoft.2014.11.006 VL - 64 IS - 1 SP - 205-214 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84937157028&partnerID=MN8TOARS KW - Model structural deficits KW - Rainfall errors KW - Stochastic uncertainty analysis KW - Bayesian bias description KW - Hydrodynamic simulations KW - Model comparison ER - TY - JOUR TI - Comparison of two stochastic techniques for reliable urban runoff prediction by modeling systematic errors AU - Giudice, Dario Del AU - Löwe, Roland AU - Madsen, Henrik AU - Mikkelsen, Peter Steen AU - Rieckermann, Jörg T2 - Water Resour. Res. AB - Abstract In urban rainfall‐runoff, commonly applied statistical techniques for uncertainty quantification mostly ignore systematic output errors originating from simplified models and erroneous inputs. Consequently, the resulting predictive uncertainty is often unreliable. Our objective is to present two approaches which use stochastic processes to describe systematic deviations and to discuss their advantages and drawbacks for urban drainage modeling. The two methodologies are an external bias description (EBD) and an internal noise description (IND, also known as stochastic gray‐box modeling). They emerge from different fields and have not yet been compared in environmental modeling. To compare the two approaches, we develop a unifying terminology, evaluate them theoretically, and apply them to conceptual rainfall‐runoff modeling in the same drainage system. Our results show that both approaches can provide probabilistic predictions of wastewater discharge in a similarly reliable way, both for periods ranging from a few hours up to more than 1 week ahead of time. The EBD produces more accurate predictions on long horizons but relies on computationally heavy MCMC routines for parameter inferences. These properties make it more suitable for off‐line applications. The IND can help in diagnosing the causes of output errors and is computationally inexpensive. It produces best results on short forecast horizons that are typical for online applications. DA - 2015/7// PY - 2015/7// DO - 10.1002/2014wr016678 VL - 5 SP - n/a-n/a KW - Bayesian uncertainty analysis KW - hydrological simulator KW - stochastic differential equations KW - statistical error model KW - urban drainage KW - model discrepancy ER - TY - RPRT TI - Accelerating Roundabouts in the United States: Volume VII of VII – Human Factor Assessment of Traffic Control Device Effectiveness AU - Findley, D. AU - Searcy, S. AU - Salamati, K. AU - Schroeder, B. AU - Williams, B. AU - Bhagavathula, R. AU - Rodegerts, L. A3 - Office of Safety. Federal Highway Administration DA - 2015/9// PY - 2015/9// M1 - FHWA-SA-15-075 PB - Office of Safety. Federal Highway Administration SN - FHWA-SA-15-075 ER - TY - RPRT TI - Accelerating Roundabouts in the United States: Volume VI of VII – Investigation of Crosswalk Design and Driver Behaviors AU - Findley, D. AU - Searcy, S. AU - Salamati, K. AU - Schroeder, B. AU - Williams, B. AU - Bhagavathula, R. AU - Rodegerts, L. A3 - Office of Safety. Federal Highway Administration DA - 2015/9// PY - 2015/9// M1 - FHWA-SA-15-074 PB - Office of Safety. Federal Highway Administration SN - FHWA-SA-15-074 ER - TY - RPRT TI - Accelerating Roundabouts in the United States: Volume IV of VII – A Review of Fatal and Severe Injury Crashes at Roundabouts AU - Schroeder, B. AU - Salamati, K. AU - Rouphail, N. AU - Findley, D. AU - Hunter, E. AU - Phillips, B. AU - Barlow, J. AU - Rodegerts, L. A3 - Office of Safety. Federal Highway Administration DA - 2015/9// PY - 2015/9// M1 - FHWA-SA-15-072 PB - Office of Safety. Federal Highway Administration SN - FHWA-SA-15-072 ER - TY - RPRT TI - Accelerating Roundabouts in the United States: Volume I of VII - Evaluation of Rectangular Rapid-Flashing Beacons (RRFB) at Multilane Roundabouts AU - Schroeder, B. AU - Salamati, K. AU - Rouphail, N. AU - Findley, D. AU - Hunter, E. AU - Phillips, B. AU - Barlow, J. AU - Rodegerts, L. A3 - Office of Safety. Federal Highway Administration DA - 2015/9// PY - 2015/9// M1 - FHWA-SA-15-069 PB - Office of Safety. Federal Highway Administration SN - FHWA-SA-15-069 ER - TY - BOOK TI - Introduction AU - Findley, D.J. AB - This part provides a summary of the topics covered in this book. DA - 2015/// PY - 2015/// DO - 10.1016/B978-0-12-801248-2.00001-0 SE - 1-16 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84961183305&partnerID=MN8TOARS ER - TY - BOOK TI - Horizontal and Vertical Alignment AU - Findley, Daniel AB - This part describes the decisions related to choosing an optimal highway alignment given substantial environmental and design considerations, including: corridor selection, traverses, sight distance, horizontal alignment, and vertical alignment. Corridor selection is comprised of the broad task of choosing a highway location through decisions relating to minimizing costs and impacts to the human and natural environment. The engineering computations of such corridors are derived from consideration of the highway segments as a traverse. The horizontal and vertical components each affect the highway location and require an iterative process to balance the various quantitative measures and tradeoffs of a particular alternative, as well as include feedback gathered from stakeholders in the public involvement process. At any point along a highway, the driver should be able to perceive an obstruction or change in alignment and react by changing his or her speed, direction, or path. The distance required to perform this maneuver, known as the sight distance, is an integral part of highway alignment. DA - 2015/// PY - 2015/// DO - 10.1016/B978-0-12-801248-2.00003-4 SE - 89-166 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84961187300&partnerID=MN8TOARS ER - TY - BOOK TI - Highway Geometric Design AU - Findley, Daniel AB - This part details the process of choosing appropriate geometric features for a highway. Design controls govern key aspects of highway design and are essential for safety and efficiency. The geometric features considered in this part include the basic components that guide horizontal and vertical alignment, including curvature and grades, and elements that form the cross section of the highway, including lanes, shoulders, and medians. Intersections and interchanges are an important part of highway design due to their significant impact on safety performance and operational efficiency. DA - 2015/// PY - 2015/// DO - 10.1016/B978-0-12-801248-2.00004-6 SE - 167-253 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84961140350&partnerID=MN8TOARS ER - TY - BOOK TI - Highway Engineering: Planning, Design, and Operations AU - Findley, D.J. AU - Schroeder, B.J. AU - Cunningham, C.M. AU - Brown, T.H. DA - 2015/// PY - 2015/// DO - 10.1016/C2013-0-19212-4 SE - 1-714 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84961153123&partnerID=MN8TOARS ER - TY - JOUR TI - Business Perceptions of Access Management Techniques AU - Cunningham, C.M. AU - Katz, D. AU - Smith, S. AU - Carter, D. AU - Miller, M. AU - Findley, D.J. AU - Schroeder, B. AU - Foyle, R.S. T2 - Public Works Management and Policy AB - Transportation agencies have made significant strides to reduce collisions and increase capacity along strategic highway corridors. Efforts have led to the implementation of many different access management techniques along corridors, such as installing medians versus two-way left-turn lanes and closing median openings. Businesses along these corridors have indicated their concern that these new designs will have a negative economic impact on their business because of the lack of direct access to their properties. The objective of this study was to quantify the business perceptions of median treatments on businesses adjacent to multilane highways. Owners of businesses along treatment corridors viewed median installations with a more positive outlook following implementation of the median than they did prior to the installation. The performance of treatment sites in terms of reported impacts on business revenues indicates that there is no direct evidence of negative economic impacts due to median installations. DA - 2015/// PY - 2015/// DO - 10.1177/1087724X13488757 VL - 20 IS - 1 SP - 60-79 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84918512158&partnerID=MN8TOARS ER - TY - CONF TI - Illustrative comparison between rated and real-world fuel economy and emissions AU - Khan, T. AU - Frey, H.C. C2 - 2015/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2015/// VL - 3 SP - 1623-1641 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84983738698&partnerID=MN8TOARS ER - TY - CONF TI - How to train your digester - Using step and pulse feeding of grease waste to increase community resistance and methane yield by up to 336% AU - Wang, L. AU - Hossen, E.H. AU - Aziz, T.N. AU - Ducoste, J.J. AU - De Los Reyes, F.L. C2 - 2015/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2015/// VL - 3 SP - 1581-1589 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84983745996&partnerID=MN8TOARS ER - TY - JOUR TI - Assessing biophysical controls on Gulf of Mexico hypoxia through probabilistic modeling AU - Obenour, Daniel R AU - Michalak, Anna M AU - Scavia, Donald T2 - Ecological Applications DA - 2015/// PY - 2015/// VL - 25 IS - 2 SP - 492-505 ER - TY - CONF TI - BIM-Assisted Structure-from-Motion for Analyzing and Visualizing Construction Progress Deviations through Daily Site Images and BIM AU - Han, Kevin K. AU - Golparvar-Fard, Mani AB - In an effort to document work-in-progress, many construction companies take hundreds of images on their project sites on a daily basis. These images together with 4D BIM can serve as a great resource for analyzing progress deviations. To facilitate image-vs.-BIM comparison, several methods have been introduced that tie in all images together in 3D using standard Structure-from-Motion (SfM) procedures. The resulting point clouds are then superimposed with the 4D BIM, resulting in back-projection of BIM on all images that were successfully registered through the SfM procedure. However, often site images exhibit wide baselines and thus are not successfully registered with BIM. To address current limitations, this paper presents a method together with experimental results that leverages BIM as a priori to initiate the SfM procedure. It is shown that by interactively guiding BIM into one or a few images that have significant overlap with the rest, the proposed BIM-assisted SfM procedure results in more complete point clouds and also generate more accurate BIM overlays on site images. C2 - 2015/6// C3 - Computing in Civil Engineering 2015 DA - 2015/6// DO - 10.1061/9780784479247.074 PB - American Society of Civil Engineers ER - TY - JOUR TI - Appearance-based material classification for monitoring of operation-level construction progress using 4D BIM and site photologs AU - Han, Kevin K. AU - Golparvar-Fard, Mani T2 - Automation in Construction AB - This paper presents a new appearance-based material classification method for monitoring construction progress deviations at the operational-level. The method leverages 4D Building Information Models (BIM) and 3D point cloud models generated from site photologs using Structure-from-Motion techniques. To initialize, a user manually assigns correspondences between the point cloud model and BIM, which automatically brings in the photos and the 4D BIM into alignment from all camera viewpoints. Through reasoning about occlusion, each BIM element is back-projected on all images that see that element. From these back-projections, several 2D patches are sampled per element and are classified into different material types. To perform material classification, the expected material type information is derived from BIM. Then the image patches are convolved with texture and color filters and their concatenated vector-quantized responses are compared with multiple discriminative material classification models that are relevant to the expected progress of that element. For each element, a quantized histogram of the observed material types is formed and the material type with the highest appearance frequency infers the appearance and thus the state of progress. To validate, four new datasets of incomplete and noisy point cloud models are introduced which are assembled from real-world construction site images and BIMs. An extended version of the Construction Material Library (CML) is also introduced for training/testing the material classifiers. The material classification shows an average accuracy of 92.4% for CML image patches of 100 × 100 pixels. The experiments on those four datasets show an accuracy of 95.9%, demonstrating the potential of appearance-based recognition method for inferring the actual state of construction progress for BIM elements. DA - 2015/// PY - 2015/// DO - http://dx.doi.org/10.1016/j.autcon.2015.02.007 VL - 53 IS - SP - 44 - 57 UR - http://www.sciencedirect.com/science/article/pii/S0926580515000266 N1 - RN - ER - TY - JOUR TI - Formalized knowledge of construction sequencing for visual monitoring of work-in-progress via incomplete point clouds and low-LoD 4D BIMs AU - Han, K. AU - Cline, D. AU - Golparvar-Fard, M. T2 - Advanced Engineering Informatics AB - Over the last few years, new methods that detect construction progress deviations by comparing laser scanning or image-based point clouds with 4D BIM are developed. To create complete as-built models, these methods require the visual sensors to have proper line-of-sight and field-of-view to building elements. For reporting progress deviations, they also require Building Information Modeling (BIM) and schedule Work-Breakdown-Structure (WBS) with high Level of Development (LoD). While certain logics behind sequences of construction activities can augment 4D BIM with lower LoDs to support making inferences about states of progress under limited visibility, their application in visual monitoring systems has not been explored. To address these limitations, this paper formalizes an ontology that models construction sequencing rationale such as physical relationships among components. It also presents a classification mechanism that integrates this ontology with BIM to infer states of progress for partially and fully occluded components. The ontology and classification mechanism are validated using a Charrette test and by presenting their application together with BIM and as-built data on real-world projects. The results demonstrate the effectiveness and generality of the proposed ontology. It also illustrates how the classification mechanism augments 4D BIM at lower LoDs and WBS to enable visual progress assessment for partially and fully occluded BIM elements and provide detailed operational-level progress information. DA - 2015/10// PY - 2015/10// DO - 10.1016/j.aei.2015.10.006 VL - 29 IS - 4 SP - 889–901 SN - 1474-0346 KW - Sequencing knowledge KW - Visual construction monitoring KW - Building information modeling ER - TY - CONF TI - A Framework for Model-Driven Acquisition and Analytics of Visual Data Using UAVs for Automated Construction Progress Monitoring AU - Lin, Jacob J. AU - Han, Kevin K. AU - Golparvar-Fard, Mani AB - Automated assessment of work-in-progress using large collections of site images and 4D BIM has potential to significantly improve the efficiency of construction project controls. Nevertheless, today’s manual procedures for taking site photos do not support the desired frequency or completeness for automated progress monitoring. While the usage of Unmanned Aerial Vehicles for acquisition of site images has gained popularity, their application for addressing issues associated with image-based progress monitoring and particularly leveraging 4D BIM for steering the data collection process has not been investigated before. By presenting examples from two case studies conducted on real-world construction projects, this paper suggests a framework for model-driven acquisition and analytics of progress images. In particular, the potential of spatial (geometry, appearance, and interconnectivity) and temporal information in 4D BIM for autonomous data acquisition and analytics that guarantees completeness and accuracy for both as-built modeling and monitoring work-in-progress at the schedule task-level is discussed. C2 - 2015/6// C3 - Computing in Civil Engineering 2015 DA - 2015/6// DO - 10.1061/9780784479247.020 PB - American Society of Civil Engineers ER - TY - CONF TI - Properties of activated crumb rubber modified binders AU - Medina, J. AU - Kaloush, K. AU - Underwood, B.S. C2 - 2015/// C3 - Proceedings of the 6th Asphalt Rubber Conference DA - 2015/// ER - TY - CONF TI - Properties of Arizona TR+ binders in multiple stress creep and recovery test AU - Stempihar, J. AU - Stevens, S. AU - Underwood, B.S. AU - Dharminder, P. C2 - 2015/// C3 - Proceedings of the 6th Asphalt Rubber Conference DA - 2015/// ER - TY - CONF TI - Laboratory cracking evaluation of a warm mix rubber modified pavement AU - Stempihar, J. AU - Zeiada, W. AU - Underwood, B.S. AU - Kaloush, K. C2 - 2015/// C3 - Proceedings of the 6th Asphalt Rubber Conference DA - 2015/// ER - TY - RPRT TI - Indiana state highway cost allocation and revenue attribution study and estimation of travel by out-of-state vehicles on Indiana highways AU - Volovski, M. AU - Bardaka, Eleni AU - Zhang, Z. AU - Agbelie, B. AU - Labi, S. AU - Sinha, K.C. AB - This study was commissioned by INDOT to investigate the cost responsibility and the revenue contribution of highway users with regard to the upkeep of Indiana’s state and local highway infrastructure (pavements, bridges, safety assets, and mobility assets). The costs consisted of expenditures on construction, preservation, maintenance, and operations of the highway infrastructure. For revenues, user and non-user sources were considered. The highway users were represented by the 13 FHWA vehicle classes, and the study was based on 2009-2012 data on expenditures and revenues. The study framework duly recognized the dichotomy between attributable and common costs. For allocating the attributable costs to the vehicle classes, ESALs, AASHTO loading equivalents, and PCEs were used; for allocating common costs, VMT was used. For each vehicle class, the share of revenue contribution was compared to the share of cost responsibility to determine respective equity ratios and thus to ascertain the extent to which vehicles in each class may be underpaying or overpaying their cost responsibilities at the current time. The study also determined the distribution of fuel purchases and travel by out-of-state vehicles on Indiana’s highways; this analysis was required to further refine the results of the cost allocation and also to quantify the magnitude of any imbalance between the out-of-state travel and share of consumption on Indiana’s infrastructure and the revenue from such out-of-state vehicles. The outcome of this research is a systematic documentation of the sources and extents of highway revenues and the areas of expenditures at the local and state levels in Indiana. Pavement and bridge expenditures were found to have a dominant share of the overall expenditures on Indiana’s highway system. Classes 2 (automobiles) and 9 (5-axle combination trucks) were found to have a dominant share of the cost responsibilities. It was determined that the user revenue sources contributed approximately 64% of the total state funding for highway expenditures and 36% were from non-user revenue sources. On the basis of the expenditures and revenues associated with the various user groups (vehicle classes) over the analysis period, this study found that inequities exist, albeit in varying degrees, among the highway user groups. Of the 13 vehicle classes, classes 1–4 were found to be overpaying their cost responsibilities while classes 5–13 are underpaying. For example, vehicle class 2 is overpaying its cost responsibility by 8% while vehicle class 9 is underpaying by 16%. It was also found that out-of-state on Indiana’s interstates, NHS non-interstates, non-NHS and local roads were 21%, 10%, 9%, and 7% respectively, of the total travel as a percentage of VMT on those families of highway systems. DA - 2015/// PY - 2015/// DO - 10.5703/1288284315709 ER - TY - CHAP TI - Chapter 9: Multiscale Modeling Approach for Asphalt Concrete and its Implications on Oxidative Aging AU - Underwood, B.S. T2 - Advances in Asphalt Materials A2 - Huang, Shin-Che A2 - Benedetto, Herve? Di PY - 2015/// PB - Cambridge: Woodhead Publishing SN - 9780081002711 ER - TY - CONF TI - Techniques for selecting cost-effective pavement rehabilitation strategies AU - Nobakht, M. AU - Sakhaeifar, M.S. AU - Newcomb, D. AU - Underwood, B.S. AU - Freeman, T. C2 - 2015/// C3 - ASCE T&DI 2015 Annual Meeting DA - 2015/// ER - TY - CONF TI - Multiaxial viscoelastic continuum damage model under compressive and tensile deviatoric loading AU - Underwood, B.S. C2 - 2015/// C3 - 94th Annual Meeting of the Transportation Research Board DA - 2015/// ER - TY - CONF TI - Impact of freight movement trends on highway pavement infrastructure AU - Nagarajan, S. AU - Underwood, B.S. C2 - 2015/// C3 - 2015 Roads and Streets Conference DA - 2015/// ER - TY - CONF TI - Fiber reinforced asphalt concrete: Performance tests and pavement design consideration AU - Kaloush, K.E. AU - Underwood, B.S. AU - Zeiada, W.A. AU - Stempihar, J. C2 - 2015/// C3 - International Conference on Bituminous Mixtures and Pavements DA - 2015/// ER - TY - CONF TI - Fiber reinforced asphalt concrete: Overview, mechanisms, and applications AU - Underwood, B.S. C2 - 2015/// C3 - 4th IRF Middle East Regional Congress DA - 2015/// ER - TY - JOUR TI - Continuum damage based constitutive model for asphalt binder and asphalt mastic AU - Underwood, B.S. T2 - International Journal of Fatigue DA - 2015/// PY - 2015/// VL - 82 IS - 3 SP - 287-401 ER - TY - JOUR TI - Ageing and rejuvenators: evaluating their impact on high RAP mixtures fatigue cracking characteristics using advanced mechanistic models and testing methods AU - Mogawer, Walaa S. AU - Austerman, Alexander AU - Roque, Reynaldo AU - Underwood, Shane AU - Mohammad, Louay AU - Zou, Jian T2 - Road Materials and Pavement Design AB - Fatigue cracking of asphalt mixtures is highly dependent on ageing. Using larger amounts of reclaimed asphalt pavement (RAP) presents a concern that the resultant mixtures may be prone to fatigue cracking because of the aged binder in the RAP. Several studies have indicated that asphalt rejuvenators can allow more aged binder to be incorporated into asphalt mixtures. The four-point flexural beam fatigue test, HMA (hot-mix asphalt) fracture mechanics model, simplified viscoelastic continuum damage model, and the semi-circular bending test were used to evaluate the effect of ageing on the fatigue characteristics of high RAP mixtures modified with rejuvenators. The results from these tests were compared to see if they provided similar performance trends. The results indicated that the long-term ageing used in this study did not have a significant effect on the fatigue characteristics of the high RAP mixture with and without rejuvenators. Comparison of the fatigue tests did not show universal agreement. DA - 2015/8/20/ PY - 2015/8/20/ DO - 10.1080/14680629.2015.1076996 VL - 16 IS - sup2 SP - 1-28 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2015.1076996 DB - Crossref KW - ageing KW - reclaimed asphalt pavement KW - asphalt rejuvenator KW - fatigue cracking performance ER - TY - JOUR TI - Testing and modeling of fine aggregate matrix to asphalt mixture damage relationship AU - Gudipudi, P. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2015/// PY - 2015/// VL - 2507 SP - 120-127 ER - TY - JOUR TI - Multidimensional Vascularized Polymers using Degradable Sacrificial Templates AU - Gergely, Ryan C. R. AU - Pety, Stephen J. AU - Krull, Brett P. AU - Patrick, Jason F. AU - Doan, Thu Q. AU - Coppola, Anthony M. AU - Thakre, Piyush R. AU - Sottos, Nancy R. AU - Moore, Jeffrey S. AU - White, Scott R. T2 - ADVANCED FUNCTIONAL MATERIALS AB - Complex multidimensional vascular polymers are created, enabled by sacrificial template materials of 0D to 3D. Sacrificial material consisting of the commodity biopolymer poly(lactic acid) is treated with a tin catalyst to accelerate thermal depolymerization, and formed into sacrificial templates across multiple dimensions and spanning several orders of magnitude in scale: spheres (0D), fibers (1D), sheets (2D), and 3D printed. Templates are embedded in a thermosetting polymer and removed using a thermal treatment process, vaporization of sacrificial components (VaSC), leaving behind an inverse replica. The effectiveness of VaSC is verified both ex situ and in situ, and the resulting structures are validated via flow rate testing. The VaSC platform is expanded to create vascular and porous architectures across a wide range of size and geometry, allowing engineering applications to take advantage of vascular designs optimized by biology. DA - 2015/2/18/ PY - 2015/2/18/ DO - 10.1002/adfm.201403670 VL - 25 IS - 7 SP - 1043-1052 SN - 1616-3028 ER - TY - JOUR TI - Unified failure criterion for asphalt binder under cyclic fatigue loading AU - Wang, Chao AU - Castorena, Cassie AU - Zhang, Jinxi AU - Kim, Y. Richard T2 - ROAD MATERIALS AND PAVEMENT DESIGN AB - Defining failure and developing a unified failure criterion for the fatigue testing of asphalt materials remain a challenge. This study seeks to develop a failure criterion for the fatigue testing of asphalt binders under cyclic loading in the dynamic shear rheometer. Newly developed pseudo-strain energy (PSE)-based failure analysis is introduced for both the time sweep fatigue test and the accelerated linear amplitude sweep (LAS) test (AASHTO TP101). The presented methodology builds upon recent advances in the simplified viscoelastic continuum damage (S-VECD) modelling of asphalt mixtures. Trends in stored PSE have been proven to be effective in defining failure for the LAS tests of asphalt binders. This new proposed failure definition is material-dependent and, thus, is effective in capturing the benefits of asphalt modification for binder fatigue resistance. In addition, it is found that a unique relationship that is independent of loading history exists between the PSE release rate and fatigue life. The fatigue life predictions using this relationship and the S-VECD model are in reasonable agreement with the laboratory-measured fatigue life data and also generally relate well with the field fatigue performance measured in the FHWA-ALF (Federal Highway Administration – Accelerated Loading Facility) pooled fund study. DA - 2015/// PY - 2015/// DO - 10.1080/14680629.2015.1077010 VL - 16 SP - 125-148 SN - 2164-7402 KW - failure criterion KW - asphalt fatigue KW - pseudo-strain energy KW - damage KW - S-VECD KW - fatigue life ER - TY - CONF TI - Simulating mechanical response in bio-cemented sands AU - Evans, T. M. AU - Khoubani, A. AU - Montoya, B. M. C2 - 2015/// C3 - Computer Methods and Recent Advances in Geomechanics DA - 2015/// SP - 1569-1574 ER - TY - JOUR TI - Modified auger for pit latrine desludging in developing countries AU - Sisco, Tracey AU - Rogers, Tate AU - Reyes, Francis T2 - HUMANITARIAN TECHNOLOGY: SCIENCE, SYSTEMS AND GLOBAL IMPACT 2015, HUMTECH2015 AB - A modified auger was developed in response to the need for a hygienic and low-cost pit emptying technology. An auger is housed inside a 4” pipe and powered by a hydraulic motor. As the auger turns, sludge is conveyed up and out of the pit into containers for disposal. Development and lab testing of prototypes was followed by field-testing on pit latrines in South Africa. Flow rates up to 40 LPM were achieved in field-testing, which are high enough to empty a typical pit in 1 to 2 hours. Field testing also revealed new challenges and progress has continued in order to solve these problems, including improved manoeuvrability and management of trash often found in latrines. The addition of a dolly frame improved the movement of the auger inside and outside of the pits. Trash removal technologies that could be coupled with the auger are currently in development. Further field-testing of the auger and trash management techniques will be carried out. DA - 2015/// PY - 2015/// DO - 10.1016/j.proeng.2015.06.101 VL - 107 SP - 427-429 SN - 1877-7058 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946054501&partnerID=MN8TOARS KW - pit latrine emptying KW - fecal sludge management ER - TY - CONF TI - Deformation of microbial induced calcite bonded sands: A micro-scale investigation AU - Montoya, B. AU - Feng, K. C2 - 2015/// C3 - Deformation characteristics of geomaterials DA - 2015/// VL - 6 SP - 978-985 ER - TY - JOUR TI - A comprehensive evaluation of the fatigue behaviour of plant-produced RAP mixtures AU - Sabouri, Mohammadreza AU - Bennert, Thomas AU - Daniel, Jo Sias AU - Kim, Y. Richard T2 - ROAD MATERIALS AND PAVEMENT DESIGN AB - In this study, the fatigue performance of 12 plant-produced mixtures from New Hampshire and Vermont that contain reclaimed asphalt pavement (RAP) contents of 0–40% by total weight of mixture was evaluated. The mixture tests included dynamic modulus, uniaxial fatigue, beam fatigue, and overlay tests. Also, the simplified viscoelastic continuum damage (S-VECD) model failure criterion, called the GR method, was applied and input to the linear viscoelastic pavement analysis for critical distresses (LVECD) programme to predict the fatigue behaviour of the tested mixtures on thin and thick asphalt pavement structures. In order to explain the observed fatigue behaviour, the performance grades (PGs) of the binders that were extracted and recovered from the mixtures were determined. In general, the addition of RAP resulted in an increase in the stiffness of the materials. The magnitude of the impact of higher RAP percentages varied with each set of mixtures. The S-VECD model and beam fatigue test data showed a loss of fatigue resistance for high-percentage RAP mixtures in most of the cases. The overlay tester results showed clear drops in performance at higher RAP contents. The impact of lowering the PG of the virgin binder to compensate for higher levels of RAP also was studied. Lowering the PG led to improvement in the fatigue properties and was found to be a convenient practice. The changes in the measured properties also appeared to be a function of mix design variables that included the stiffness of the RAP, asphalt content, and production parameters such as silo storage times. In some cases, the effects of these factors outweighed the impact of the RAP level or PG of the virgin binder in the mixtures. DA - 2015/// PY - 2015/// DO - 10.1080/14680629.2015.1076997 VL - 16 SP - 29-54 SN - 2164-7402 KW - reclaimed asphalt pavement KW - fatigue KW - asphalt KW - failure criterion KW - damage ER - TY - CONF TI - Long and short radius elbow experiments and evaluation of advanced constitutive models to simulate the responses AU - Islam, N. AU - Fenton, M. AU - Hassan, T. AB - Low-cycle fatigue (LCF) and strain ratcheting responses of long and short radius elbows are studied experimentally and analytically. Elbow piping components are widely used in piping systems, however, the prediction of their low-cycle fatigue and ratcheting responses remain a challenge. Hence, a systematic set of short and long radius elbow LCF responses are developed by prescribing displacement-controlled loading cycles with or without internal pressure. A setup comprised of four LVDTs was utilized to measure diameter change during cyclic loading. In order to evaluate the accuracy of the strain gage data, strains are also acquired using the digital image correlation (DIC) technique. Recorded fatigue responses are analyzed in understanding the differences in LCF lives between the long and short radius elbows. The Chaboche nonlinear kinematic hardening constitutive model in ANSYS and a modified version of this model are evaluated for their simulation capability against the recorded elbow responses. The experimental and finite element simulation responses are presented in this article. C2 - 2015/// C3 - Asme Pressure Vessels and Piping Conference - 2015, vol 8 DA - 2015/// DO - 10.1115/pvp2015-45688 ER - TY - CONF TI - A unified viscoplastic model for creep and fatigue-creep response simulation of Haynes 230 AU - Barrett, P. R. AU - Hassan, T. AB - A Chaboche-based unified viscoplastic constitutive model, including features of strain range dependence, strain rate-dependence, static recovery, and mean stress evolution is developed and evaluated for simulating fatigue-creep and creep responses of Haynes 230. In other words, this constitutive model attempt to simulate not only strain-controlled fatigue and fatigue-creep responses of Haynes 230, but also stress-controlled creep responses. After investigating various flow rules and kinematic hardening rules, a unified viscoplastic constitutive model is developed for simulating both the fatigue-creep and creep responses. The parameter determination for this constitutive model, however, requires a robust optimization algorithm. The proposed unified constitutive model can adequately simulate fatigue-creep responses, and creep responses up to the secondary creep regimes. However, with the introduction of damage modeling features the constitutive model can simulate the tertiary creep regime responses, but with some limitations in simulating fatigue-creep responses. Nonetheless, the unified viscoplastic constitutive model with or without damage modeling features has shown to be able to capture the stress-controlled creep responses while still maintaining high fidelity in capturing the strain-controlled fatigue and fatigue-creep responses. C2 - 2015/// C3 - ASME Pressure Vessels and Piping Conference - 2015, vol 3 DA - 2015/// DO - 10.1115/pvp2015-45671 ER - TY - JOUR TI - Agent Based Framework For Modeling Operations at Isolated Signalized Intersections AU - Isukapati, Isaac K. AU - List, George F. T2 - 2015 IEEE 18TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS AB - An agent-based model of intersection control is presented. Drivers make payments to movement managers so that they can pass through the intersection. Movement managers collect fees from arriving drivers, receive voluntary contributions from those same drivers, and participate in a bidding process overseen by the municipality which determines which movement mangers get to discharge vehicles. Winning movement managers get to discharge vehicles from their queues for the duration of time associated with the win. A realization of the model is presented to illustrate these ideas. It involves two approaches, arriving drivers, two movement managers, and a municipality. The movement managers control the conflicting one-way traffic streams. They determine what bids to submit given the status of the system at each point in time, recalibrate those strategies based on past experience with their use, forecast the performance of those strategies, take actions based on those analyses, and then repeat the process in each time step as the simulation unfolds. DA - 2015/// PY - 2015/// DO - 10.1109/itsc.2015.477 SP - 2900-2906 SN - 2153-0009 ER - TY - JOUR TI - Decomposition of sources of errors in seasonal streamflow forecasting over the U.S. Sunbelt AU - Mazrooei, Amirhossein AU - Sinha, Tushar AU - Sankarasubramanian, A. AU - Kumar, Sujay AU - Peters‐Lidard, Christa D. T2 - Journal of Geophysical Research: Atmospheres AB - Abstract Seasonal streamflow forecasts, contingent on climate information, can be utilized to ensure water supply for multiple uses including municipal demands, hydroelectric power generation, and for planning agricultural operations. However, uncertainties in the streamflow forecasts pose significant challenges in their utilization in real‐time operations. In this study, we systematically decompose various sources of errors in developing seasonal streamflow forecasts from two Land Surface Models (LSMs) (Noah3.2 and CLM2), which are forced with downscaled and disaggregated climate forecasts. In particular, the study quantifies the relative contributions of the sources of errors from LSMs, climate forecasts, and downscaling/disaggregation techniques in developing seasonal streamflow forecast. For this purpose, three month ahead seasonal precipitation forecasts from the ECHAM4.5 general circulation model (GCM) were statistically downscaled from 2.8° to 1/8° spatial resolution using principal component regression (PCR) and then temporally disaggregated from monthly to daily time step using kernel‐nearest neighbor (K‐NN) approach. For other climatic forcings, excluding precipitation, we considered the North American Land Data Assimilation System version 2 (NLDAS‐2) hourly climatology over the years 1979 to 2010. Then the selected LSMs were forced with precipitation forecasts and NLDAS‐2 hourly climatology to develop retrospective seasonal streamflow forecasts over a period of 20 years (1991–2010). Finally, the performance of LSMs in forecasting streamflow under different schemes was analyzed to quantify the relative contribution of various sources of errors in developing seasonal streamflow forecast. Our results indicate that the most dominant source of errors during winter and fall seasons is the errors due to ECHAM4.5 precipitation forecasts, while temporal disaggregation scheme contributes to maximum errors during summer season. DA - 2015/12// PY - 2015/12// DO - 10.1002/2015jd023687 VL - 120 IS - 23 SP - J2 - J. Geophys. Res. Atmos. LA - en OP - SN - 2169-897X 2169-8996 UR - http://dx.doi.org/10.1002/2015jd023687 DB - Crossref ER - TY - JOUR TI - Application of waste rubber to reduce the settlement of road embankment AU - Tafreshi, S. N. M. AU - Norouzi, A. H. T2 - Geomechanics and Engineering AB - In this paper, a series of repeated load tests were carried out on a 150 mm diameter plate simulative of vehicle passes, to demonstrate the benefits of soil-rubber shred mixture in decreasing the soil surface settlement of road embankment. The results show that the efficiency of rubber reinforcement is significantly a function of the rubber content, thickness of rubber-soil mixture and soil cap thickness over the mixture. Minimum surface settlement is provided by 2.5% of rubber in rubber-soil mixture, the thickness of mixture layer and soil cap of 0.5 times the loading surface diameter, giving values of 0.32-0.68 times those obtained in the unreinforced system for low and high values of amplitude of repeated load. In this installation, in contrast with unreinforced bed that shows unstable response, the rate of enhancement in settlement decreases significantly as the number of loading cycles increase and system behaves resiliently without undergoing plastic deformation. The findings encourage the use of rubber shreds obtained from non-reusable tires as a viable material in road works. DA - 2015/// PY - 2015/// DO - 10.12989/gae.2015.9.2.219 VL - 9 IS - 2 SP - 219-241 ER - TY - JOUR TI - Use of Mechanistic Models to Investigate Fatigue Performance of Asphalt Mixtures Effects of Asphalt Mix Design Targets and Compaction AU - Lee, Jong-Sub AU - Gibson, Nelson AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Effects of design air void contents, design voids in mineral aggregate (VMA), and in-place air voids on the fatigue performance of asphalt mixtures were investigated with mechanistic analyses based on the viscoelastic continuum damage (VECD) analyses and the mechanistic–empirical pavement analysis using the AASHTOWare Pavement ME Design program. The VECD analyses included the simplified viscoelastic continuum damage model at the material level and two structural models: ( a) layered viscoelastic analysis and ( b) layered viscoelastic pavement analysis for critical distresses. The mix design of a 2013 accelerated loading facility test lane was selected to develop the volumetric mix designs with the design air voids of 3%, 4%, and 5%, design VMAs of 13%, 14%, and 15%, and in-place air void contents of 5%, 7%, and 9% with the Bailey method. Dynamic modulus and direct tension cyclic fatigue tests were performed in accordance with the AASHTO TP 107 procedure. The test results showed that the linear viscoelastic property was affected by the design VMA, design air void content, and in-place air void content in order of sensitivity. Also, the damage states at failure determined from the damage characteristic curves and the mechanistic fatigue predictions had consistent trends as observed for the design VMA, in-place air void, and design air void content in rank of sensitivity. Finally, the design VMA, in-place air void, and design air void parameters were found to be sensitive in the mechanistic analyses, whereas the parameter that was most sensitive in the pavement mechanistic–empirical analysis was the in-place air void content. DA - 2015/// PY - 2015/// DO - 10.3141/2507-12 IS - 2507 SP - 108-119 SN - 2169-4052 ER - TY - JOUR TI - Seismic fragility of RC shear walls in nuclear power plant part 2: Influence of uncertainty in material parameters on fragility of concrete shear walls AU - Syed, Sammiuddin AU - Gupta, Abhinav T2 - NUCLEAR ENGINEERING AND DESIGN AB - Part 2 of this two-part manuscript builds upon the conclusions from Part 1 by evaluating whether or not it is important to considering uncertainties in material constitutive model parameters in the fragility assessment of concrete shear walls. A particular application of a box-shaped shear wall is considered because this particular specimen was tested in the past under the JNES/NUPEC program in Japan and has been used extensively by various researchers around the world to conduct studies on reconciliation of experimental and analytical results. A simulation-based fragility evaluation framework is presented in this paper. The uniqueness of this framework lies in incorporation of the uncertainties and randomness associated with the parameters of damage plasticity model as well as earthquake input motions, which are essential for estimating the demands. Unlike most of the previous studies that focus mostly on shear capacity, two different performance limit states based on maximum shear strains and maximum shear force are considered in the fragility assessment. For each performance limit state, variation in the probability of failure due to uncertainties in the material constitutive model is determined for illustrating the significance of considering such uncertainties. DA - 2015/12/15/ PY - 2015/12/15/ DO - 10.1016/j.nucengdes.2015.09.038 VL - 295 SP - 587-596 SN - 1872-759X ER - TY - JOUR TI - Seismic fragility of RC shear walls in nuclear power plant Part 1: Characterization of uncertainty in concrete constitutive model AU - Syed, Sammiuddin AU - Gupta, Abhinav T2 - NUCLEAR ENGINEERING AND DESIGN AB - This two part manuscript proposes a framework for seismic fragility assessment of reinforced concrete structures in nuclear energy facilities. The novelty of the proposed approach lies in the characterization of uncertainties in the parameters of the material constitutive model. Concrete constitutive models that comprehensively address different damage states such as tensile cracking, compression failure, stiffness degradation, and recovery of degraded stiffness due to closing of previously formed cracks under dynamic loading are generally defined in terms of a large number of variables to characterize the plasticity and damage at material level. Over the past several years, many different studies have been presented on evaluation of fragility for reinforced concrete structures using nonlinear time history simulations. However, almost all of these studies do not consider uncertainties in the parameters of a comprehensive constitutive model. Part-I of this two-part manuscript presents a study that is used to identify uncertainties associated with the critical parameters in nonlinear concrete damage plasticity model proposed by Lubliner et al. (1989. Int. J. Solids Struct., 25(3), 299) and later modified by Lee and Fenves (1998a. J. Eng. Mech., ASCE, 124(8), 892) and Lee and Fenves (1998b. Earthquake Eng. Struct. Dyn., 27(9), 937) for the purpose of seismic fragility assessment. The limitations in implementation of the damage plasticity model within a finite element framework and hence its direct use in a simulation based fragility assessment is addressed. A methodology to overcome these limitations by combining the damage plasticity based constitutive model with some existing closed-form expressions is presented in this study. A simulation-based fragility evaluation framework that incorporates the damage plasticity model and the closed-form expressions for evaluating damage variables and application of this framework to an experimentally tested shear wall is presented in the Part-II companion paper. DA - 2015/12/15/ PY - 2015/12/15/ DO - 10.1016/j.nucengdes.2015.09.037 VL - 295 SP - 576-586 SN - 1872-759X ER - TY - CONF TI - Pulse phase thermography inspection of bond defects in environmentally conditioned FRP-to-concrete specimens AU - Mabry, N. AU - Seracino, R. AU - Peters, K. AB - Externally bonded fiber-reinforced polymer (FRP) composite systems have emerged over the last few decades as an effective means for strengthening concrete structures. Typically these systems are installed by a process known as wet lay-up which involves the saturation of dry fibers with epoxy and applying them to the surface of a concrete member. This in-situ manual process is widely susceptible to a number of defects along the bondline due to entrapped air, moisture and other foreign inclusions. While current guidelines suggest acceptable defect sizes without the need for repair, significant research is still needed that examines the non-destructive evaluation (NDE) of such defects and the durability of FRP strengthened structures in extreme environments. Due to the speed and ease of application, acoustic sounding (hammer tapping) is among the most common inspection methods, but it is considered insufficient due to the limited information it provides and its accuracy depends on user interpretation. To this end, many have turned to Infrared Thermography (IRT) as an alternative whose use has been demonstrated by several researchers. However, its effectiveness is also affected by the operating environment. Occurrences such as surface reflection, humidity and non-uniform heating can lead to false readings that produce an inaccurate assessment of bond quality. Pulse Phase Thermography (PPT), a derivative technique, has been shown to overcome such issues by performing a Fourier Transform on the thermal data captured during the cooling period. PPT not only enables the removal of thermal noise by observing the phase values in the frequency domain, it also enjoys the benefit of rapid deployment by using shorter heating periods. This paper presents the results from a study involving the environmental conditioning of small scale, single-lap FRP-to-concrete pull-test specimens. Fifteen specimens were manufactured with and without pre-existing bond defects and were subjected to water submersion and freeze-thaw protocols. PPT inspection images were taken before and after the conditioning to observe the growth of defected areas as a result of conditioning. Also the tested performance of these specimens was examined to assess the criticality of discovered flaws. Finally, conclusions are made on the durability of the FRP-to-concrete interface when defects are initially present. doi: 10.12783/SHM2015/55 C2 - 2015/// C3 - Structural health monitoring 2015: system reliability for verification and implementation, vols. 1 and 2 DA - 2015/// DO - 10.12783/shm2015/55 SP - 424-431 ER - TY - JOUR TI - Investigating reflective cracking mechanisms in grid-reinforced asphalt specimens use of four-point bending notched beam fatigue tests and digital image correlation AU - Safavizadeh, S. A. AU - Wargo, A. AU - Guddati, M. AU - Kim, Y. R. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2507 SP - 29-38 ER - TY - CONF TI - Estimating the mechanical properties of layered media using ultrasonics: Numerical study with high resolution wave propagation AU - Rashetnia, R. AU - Pour-Ghaz, M. AB - Estimating the mechanical properties of layered media using ultrasonics is challenging due to the ill-posed, nonconvex, and nonlinear nature of the problem. To address this challenge, we use Kurganov Tadmor (KT) central scheme for the forward model of wave propagation since it provides a robust model for layered media with sharp boundaries. KT also minimizes numerical challenges such as dispersion error propagation. In this study, we consider a one-dimensional stress wave propagation problem. To solve the inverse problem of estimating the mechanical properties, we utilize non-heuristic random search algorithm with surrogate model. The random search algorithm performs a global search within the feasible search area, and the surrogate model applies an artificial Neural Network and a genetic algorithm to produce optimal estimations. This method also decreases the computational cost. The results show that this method can be successfully used to estimate the mechanical properties of the layered one-dimensional media. doi: 10.12783/SHM2015/318 C2 - 2015/// C3 - Structural health monitoring 2015: system reliability for verification and implementation, vols. 1 and 2 DA - 2015/// DO - 10.12783/shm2015/318 SP - 2559-2566 ER - TY - CONF TI - Electrical impedance tomography-based sensing skin for structural health monitoring AU - Hallaji, M. AU - Seppaznen, A. AU - Pour-Ghaz, M. AB - In this paper, we develop a multi-layer multi-functional electrical impedance tomography-based sensing skin. This sensing skin is made of two layers. The electrical conductivity of one layer changes due to cracking and the presence of chloride ions, while the electrical conductivity of the other layer changes only due to cracking. We monitor the local change in conductivity of each layer with Electrical Impedance Tomography (EIT). This sensing skin enables detection and differentiation of both cracking and the presence of chloride ions. We apply this sensing skin to concrete substrate. The results indicate that the developed technology can be potentially used for health monitoring of critical infrastructure systems where cracking and leakage of certain ions might be of concern. doi: 10.12783/SHM2015/381 C2 - 2015/// C3 - Structural health monitoring 2015: system reliability for verification and implementation, vols. 1 and 2 DA - 2015/// DO - 10.12783/shm2015/381 SP - 3081-3088 ER - TY - JOUR TI - Dynamic traffic flow model for travel time estimation AU - Yi, T. AU - Williams, B. M. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2526 SP - 70-78 ER - TY - JOUR TI - U.S. Air Quality and Health Benefits from Avoided Climate Change under Greenhouse Gas Mitigation AU - Garcia-Menendez, Fernando AU - Saari, Rebecca K. AU - Monier, Erwan AU - Selin, Noelle E. T2 - Environmental Science & Technology AB - We evaluate the impact of climate change on U.S. air quality and health in 2050 and 2100 using a global modeling framework and integrated economic, climate, and air pollution projections. Three internally consistent socioeconomic scenarios are used to value health benefits of greenhouse gas mitigation policies specifically derived from slowing climate change. Our projections suggest that climate change, exclusive of changes in air pollutant emissions, can significantly impact ozone (O3) and fine particulate matter (PM2.5) pollution across the U.S. and increase associated health effects. Climate policy can substantially reduce these impacts, and climate-related air pollution health benefits alone can offset a significant fraction of mitigation costs. We find that in contrast to cobenefits from reductions to coemitted pollutants, the climate-induced air quality benefits of policy increase with time and are largest between 2050 and 2100. Our projections also suggest that increasing climate policy stringency beyond a certain degree may lead to diminishing returns relative to its cost. However, our results indicate that the air quality impacts of climate change are substantial and should be considered by cost-benefit climate policy analyses. DA - 2015/6/22/ PY - 2015/6/22/ DO - 10.1021/acs.est.5b01324 VL - 49 IS - 13 SP - 7580-7588 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.5b01324 DB - Crossref ER - TY - JOUR TI - Statistical Analysis of Secondary Water Quality Impacts from Enhanced Reductive Bioremediation AU - Tillotson, J. M. AU - Borden, R. C. T2 - GROUND WATER MONITORING AND REMEDIATION AB - Abstract Enhanced reductive bioremediation ( ERB ) is effective for treating a broad range of groundwater contaminants, but does result in secondary water quality impacts ( SWQIs ). Monitoring data from 47 ERB projects were analyzed to gain a better understanding of the formation and extent of SWQIs . The database analysis revealed that SWQIs occur at virtually every site, including reduced levels of background aqueous electron acceptors ( O 2 , NO 3 − , and SO 4 2 − ), increases in dissolved‐phase metals (Fe and Mn), and the production of CH 4 . However, the SWQI “plume” that is produced is usually confined within the original contaminant plume. As a result, SWQIs from ERB are unlikely to adversely impact potable water supplies. SWQIs do attenuate with distance downgradient, with concentrations often returning to near background levels. The results of the database analysis were combined with previous research to develop a general conceptual model ( CM ) of SWQI production, mobilization, and attenuation. This CM can assist in identifying conditions where SWQIs may pose a concern. These can include sites with low iron/high sulfate ( H 2 S mobilization), high groundwater velocity ( SWQIs at distances far downgradient), and sites with low CH 4 anaerobic oxidation rates ( CH 4 migration). DA - 2015/// PY - 2015/// DO - 10.1111/gwmr.12132 VL - 35 IS - 4 SP - 67-77 SN - 1745-6592 ER - TY - JOUR TI - Rumble Strip Gaps for High-Speed Bicycles AU - O'Brien, Sarah Worth AU - Jackson, Kristy N. AU - Vosburgh, Erik AU - Findley, Daniel T2 - TRANSPORTATION RESEARCH RECORD AB - Shoulder rumble strips (SRSs) are a proven safety countermeasure that reduces motor vehicle lane departures; however, they may be seen as an impediment to bicycle travel because they decrease comfort for bicyclists and can affect riders' control while bicycling. Existing literature provides recommendations for the placement of regular gaps in SRSs, but the supporting research is limited to low and moderate bicycle speeds. Roads with SRSs along long, steep grades present a unique set of risks for cyclists because of the possibility of higher bicycle speeds. This study evaluated how variations in SRS gap lengths and shoulder widths affected bicyclists' ability to maneuver through these gaps when riding at higher than average speeds. The findings suggest that as gap length increases, bicyclists may increase downhill speed while reporting fewer instances of discomfort when attempting to cross larger gaps. The likelihood of a bicyclist hitting a simulated rumble strip while crossing a gap decreases modestly as the gap size increases. Shoulder widths in excess of 4 ft do not appear to significantly influence bicyclists' capability of maneuvering across different gap lengths and had only a minor effect on bicyclists' speeds. DA - 2015/// PY - 2015/// DO - 10.3141/2520-05 VL - 2520 IS - 2520 SP - 32-40 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976509792&partnerID=MN8TOARS ER - TY - JOUR TI - Probit-based pedestrian gap acceptance model for midblock crossing locations AU - Mamidipalli, S. V. AU - Sisiopiku, V. P. AU - Schroeder, B. J. AU - Elefteriadou, L. AU - Salamati, K. AU - Rouphail, N. M. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2519 SP - 128-136 ER - TY - JOUR TI - Fatigue and rutting evaluation of laboratory-produced asphalt mixtures containing reclaimed asphalt pavement AU - Sabouri, M. AU - Bennert, T. AU - Daniel, J. S. AU - Kim, Y. R. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2506 SP - 32-44 ER - TY - JOUR TI - Exploring Tradeoffs in Demand- Side and Supply- Side Management of Urban Water Resources Using Agent- Based Modeling and Evolutionary Computation AU - Kanta, Lufthansa AU - Berglund, Emily Zechman T2 - SYSTEMS AB - Urban water supply systems may be managed through supply-side and demand-side strategies, which focus on water source expansion and demand reductions, respectively. Supply-side strategies bear infrastructure and energy costs, while demand-side strategies bear costs of implementation and inconvenience to consumers. To evaluate the performance of demand-side strategies, the participation and water use adaptations of consumers should be simulated. In this study, a Complex Adaptive Systems (CAS) framework is developed to simulate consumer agents that change their consumption to affect the withdrawal from the water supply system, which, in turn influences operational policies and long-term resource planning. Agent-based models are encoded to represent consumers and a policy maker agent and are coupled with water resources system simulation models. The CAS framework is coupled with an evolutionary computation-based multi-objective methodology to explore tradeoffs in cost, inconvenience to consumers, and environmental impacts for both supply-side and demand-side strategies. Decisions are identified to specify storage levels in a reservoir that trigger: (1) increases in the volume of water pumped through inter-basin transfers from an external reservoir; and (2) drought stages, which restrict the volume of water that is allowed for residential outdoor uses. The proposed methodology is demonstrated for Arlington, Texas, water supply system to identify non-dominated strategies for an historic drought decade. Results demonstrate that pumping costs associated with maximizing environmental reliability exceed pumping costs associated with minimizing restrictions on consumer water use. DA - 2015/12// PY - 2015/12// DO - 10.3390/systems3040287 VL - 3 IS - 4 SP - 287-308 SN - 2079-8954 KW - agent-based modeling KW - complex adaptive systems analysis KW - multi-objective optimization KW - urban water resources management KW - sustainability ER - TY - CONF TI - Successful academic partnership in the development of an international construction practices course AU - Jaselskis, E. J. AU - Valdes-Vasquez, R. AU - Kalidindi, S. N. AU - Krute, L. D. AU - Guo, H. L. AU - Comiskey, D. AU - Nelson, D. M. C2 - 2015/// C3 - 2015 ASEE Annual Conference and Exposition DA - 2015/// ER - TY - JOUR TI - Long-term monitoring of wrong-way maneuvers at diverging diamond interchanges AU - Vaughan, C. AU - Jagadish, C. AU - Bharadwaj, S. AU - Cunningham, C. M. AU - Schroeder, B. J. AU - Hummer, J. E. AU - Findley, D. AU - Rouphail, N. M. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2484 SP - 129-139 ER - TY - JOUR TI - Effects of Guide and Logo Signs on Freeway Driving Behavior AU - Pankok, Carl, Jr. AU - Kaber, David AU - Rasdorf, William AU - Hummer, Joseph T2 - TRANSPORTATION RESEARCH RECORD AB - In the United States, white-on-blue highway logo signs are typically used to notify drivers of food, gas, and lodging at an upcoming interchange, whereas green guide signs are used to notify drivers of the distance to upcoming cities and roadways. This study assessed driver performance and attention allocation during simulated interstate freeway driving when drivers were exposed to six-panel logo signs, nine-panel logo signs, and green guide signs. The results revealed that glance durations and fixation frequencies to green guide signs were significantly lower than they were for six-panel and nine-panel logo signs; however, no differences were found between six-panel and nine-panel logo signs. There were statistical differences between the independent variables for speed deviation and lane deviation, but the magnitudes of difference were not considered practically significant for driving safety. Overall, minor differences in sign processing time between logo signs and green guide signs did not translate into degradations in vehicle control. DA - 2015/// PY - 2015/// DO - 10.3141/2518-10 IS - 2518 SP - 73-78 SN - 2169-4052 ER - TY - JOUR TI - Thermal Cracking of Mass Concrete Bridge Footings in Coastal Environments AU - Bobko, Christopher P. AU - Edwards, Andrew J. AU - Seracino, Rudolf AU - Zia, Paul T2 - Journal of Performance of Constructed Facilities AB - The North Carolina Department of Transportation (NCDOT) identified several mass concrete footings in coastal bridges with cracking that needed to be assessed in the context of current North Carolina mass concrete specifications. Cracked concrete in coastal environments is of particular concern due to the higher potential for corrosion damage. Site visits were made to assess the extent of the cracking observed in mass concrete footings of three different bridges. A finite-element model was developed and used to analyze the footings and assess them for their early age thermal cracking potential. Finite-element model results showed that reasonably sized mass concrete footings that followed typical NCDOT control plans did not have a high likelihood of significant cracking from thermal stresses. However, a much larger mass concrete footing had a distinctly higher risk of significant cracking even when typical NCDOT control plans are followed. Further, cracking was even more likely when formwork was removed early. The model results correlated well with observations from the field. A comparison with temperature rise results from the Schmidt method, as implemented in the design of the mass concrete structural elements, shows the Schmidt method’s limitations in predicting temperature differences for very large mass concrete footings. DA - 2015/12// PY - 2015/12// DO - 10.1061/(ASCE)CF.1943-5509.0000664 VL - 29 IS - 6 SP - 04014171 J2 - J. Perform. Constr. Facil. LA - en OP - SN - 0887-3828 1943-5509 UR - http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000664 DB - Crossref KW - Bridge KW - Footing KW - Mass concrete KW - Schmidt method KW - Thermal stress ER - TY - JOUR TI - Pedestrian and bicyclist accommodations and crossings on superstreets AU - Holzem, A. M. AU - Hummer, J. E. AU - Cunningham, C. M. AU - O'Brien, S. W. AU - Schroeder, B. J. AU - Salamati, K. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2486 SP - 37-44 ER - TY - JOUR TI - Modeling vehicle-pedestrian interactions outside of crosswalks AU - Zheng, Yinan AU - Chase, Thomas AU - Elefteriadou, Lily AU - Schroeder, Bastian AU - Sisiopiku, Virginia P. T2 - SIMULATION MODELLING PRACTICE AND THEORY AB - Pedestrian and driver behaviors as well as their interactions, are essential in planning, designing and operating highway facilities. Pedestrian crossing outside of a marked or unmarked crosswalk (i.e. jaywalking), is one of those pedestrian behaviors that may highly affect safety and operations. Unlike permissible crossings at crosswalks, jaywalking events are not often anticipated by drivers, which may result in less driver reaction time and different vehicle operation dynamics. It is important to understand pedestrian crossing behavior outside of crosswalks, as well as driver yielding behavior towards them. To date, limited quantitative and behavioral research has been conducted to investigate this interaction or simulate it microscopically. This paper aims to explore both pedestrian jaywalking behavior (gap acceptance and speeds) and the corresponding driver reactions (yielding behavior) for modeling the vehicle–pedestrian interactions (VPI) outside the crosswalks in a micro-simulation environment. The study also quantifies the differences between vehicle–jaywalker and vehicle-permissible crossing. An observational study and an instrumented vehicle study were conducted on the campus of the University of Florida to collect data from pedestrian and driver perspectives, respectively. Crossing speed, yield acceptance and delay of jaywalking crossings and permissible crossings were observed in the study and these attributed can be used for replicating pedestrian operations in simulators. Moreover, behaviors of driver approaching jaywalkers versus pedestrians crossing at designated crosswalks were compared on the basis of yield rates, and vehicle speed profiles. Vehicle yield dynamics were analyzed to model the driver reactions towards jaywalkers. Lastly, it was found that the locations of jaywalking events are highly concentrated and influenced by the crossing environment, such as pedestrian and vehicular volume, bus stops presence and crossing distance. This paper establishes several quantitative relationships describing interactions between pedestrians crossing outside of crosswalks and approaching drivers, which provide the basis and assumptions for modeling such interactions in a micro-simulation environment for traffic operational analyses. DA - 2015/12// PY - 2015/12// DO - 10.1016/j.simpat.2015.08.005 VL - 59 SP - 89-101 SN - 1878-1462 KW - Pedestrian-vehicle interaction KW - Jaywalking KW - Pedestrian crossing behavior KW - Simulation ER - TY - JOUR TI - Durability and long term behavior of FRP/foam shear transfer mechanism for concrete sandwich panels AU - Kazem, Hamid AU - Bunn, William G. AU - Seliem, Hatem M. AU - Rizkalla, Sami H. AU - Gleich, Harry T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper presents an experimental program to evaluate the effect of sustained loading and outdoor exposure on the shear strength of precast concrete sandwich panels connected with FRP grid/rigid foam insulation as shear transfer mechanism. CFRP and GFRP grids were considered in this study along with EPS and XPS foam. The experimental program is comprised of three different studies with a total of 26 test panels using different combinations of FRP grid and foam insulation. DA - 2015/11/15/ PY - 2015/11/15/ DO - 10.1016/j.conbuildmat.2015.08.105 VL - 98 SP - 722-734 SN - 1879-0526 KW - Wall panels KW - CFRP grid KW - GFRP grid KW - Shear strength KW - Sustained loading KW - Outdoor exposure ER - TY - JOUR TI - Depth Detection of Bond Defects in Multilayered Externally Bonded CFRP-to-Concrete Using Pulse Phase Thermography AU - Mabry, Nehemiah J. AU - Peters, Kara J. AU - Seracino, Rudolf T2 - JOURNAL OF COMPOSITES FOR CONSTRUCTION AB - Although the practice of repairing or strengthening concrete infrastructure with externally bonded carbon-fiber-reinforced polymer (CFRP) has become common, the development of robust guidelines and techniques for its quality assurance, inspection, and monitoring is lagging significantly. Whereas common inspection methods (e.g., visual inspection or acoustic sounding) are sufficient to broadly identify deboned regions, it is difficult to reliably and accurately define the boundaries of bond defects, as is often required by acceptance criteria. Infrared thermography is a more sophisticated alternative, but the results of its application are influenced by ambient environmental conditions and operator interpretation of the data. Further, for applications in which multiple layers of CFRP are required, none of these techniques are capable of fully characterizing existing bond defects, including the depth through the thickness. To this end, pulse phase thermography (PPT) has the potential to more reliably and accurately detect the location and size of bond defects. By observing images in the frequency domain, one is able to identify a specific “blind frequency” at which a certain defect is no longer visible, and thereby also predict the defect’s depth through the thickness. This paper presents a procedure using PPT to develop a calibrated equation based on blind frequency, specific to the strengthening system, which allows for one to predict the interface at which a bond defect is present for externally bonded CFRP-to-concrete systems. With the development of more robust techniques enhancing quality assurance and reliability, and the facilitation of regular monitoring and inspection, infrastructure owners will gain more confidence in this repair or strengthening technology, ultimately leading to its widespread acceptance and adoption. DA - 2015/12// PY - 2015/12// DO - 10.1061/(asce)cc.1943-5614.0000551 VL - 19 IS - 6 SP - SN - 1943-5614 KW - Fiber-reinforced polymer KW - Bonding KW - Nondestructive tests KW - Quality control KW - Temperature effects KW - Concrete structures KW - Thermography ER - TY - JOUR TI - Comparison of Least-Cost and Least-Pollution Equipment Fleet Configurations Using Computer Simulation AU - Abbasian-Hosseini, S. Alireza AU - Liu, Min AU - Leming, Michael T2 - Journal of Management in Engineering AB - Construction vehicles and equipment, like all other fuel-powered vehicles, contribute to air pollutant emissions, such as nitrogen oxides (NOX) and particulate matter (PM). The U.S. Environmental Protection Agency has established standards for pollutant emissions for different tiers of equipment to attain a “least-pollution” equipment spread or fleet. Although using higher-tier vehicles and equipment can reduce pollutant emissions under otherwise identical conditions, policies and contractor operations can also significantly affect the total pollutant emitted for a given amount of work, such as cubic yards of earth moved or tons of surface course placed. Previous studies demonstrated the direct relationship between pollutant emissions and operational productivity and the quantitative effects of that relationship using real-world emissions data. This paper describes the results of a study conducted using computer-based simulation techniques to compare costs and pollutant emissions for a typical earth-moving project using a wheel loader and dump trucks to move a quantity of soil. Emissions were based on previously published field data. Simulation results are compared to classical, closed-form solutions from queuing theory. This study found that excess pollution—that is, the amount of pollution created without generating productive work—was lowest for the least-cost fleet and that the marginal increase in emissions was relatively small for changes in fleet configuration near the least-cost and least-pollution alternate. DA - 2015/11// PY - 2015/11// DO - 10.1061/(asce)me.1943-5479.0000360 VL - 31 IS - 6 SP - 04015003 J2 - J. Manage. Eng. LA - en OP - SN - 0742-597X 1943-5479 UR - http://dx.doi.org/10.1061/(ASCE)ME.1943-5479.0000360 DB - Crossref KW - Construction equipment KW - Emissions KW - Air pollution KW - Greenhouse gas KW - Simulation KW - Cost management ER - TY - JOUR TI - Variability in Light-Duty Gasoline Vehicle Emission Factors from Trip-Based Real-World Measurements AU - Liu, Bin AU - Frey, H. Christopher T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Using data obtained with portable emissions measurements systems (PEMS) on multiple routes for 100 gasoline vehicles, including passenger cars (PCs), passenger trucks (PTs), and hybrid electric vehicles (HEVs), variability in tailpipe emission rates was evaluated. Tier 2 emission standards are shown to be effective in lowering NOx, CO, and HC emission rates. Although PTs are larger, heavier vehicles that consume more fuel and produce more CO2 emissions, they do not necessarily produce more emissions of regulated pollutants compared to PCs. HEVs have very low emission rates compared to tier 2 vehicles under real-world driving. Emission factors vary with cycle average speed and road type, reflecting the combined impact of traffic control and traffic congestion. Compared to the slowest average speed and most congested cycles, optimal emission rates could be 50% lower for CO2, as much as 70% lower for NOx, 40% lower for CO, and 50% lower for HC. There is very high correlation among vehicles when comparing driving cycles. This has implications for how many cycles are needed to conduct comparisons between vehicles, such as when comparing fuels or technologies. Concordance between empirical and predicted emission rates using the U.S. Environmental Protection Agency's MOVES model was also assessed. DA - 2015/10/20/ PY - 2015/10/20/ DO - 10.1021/acs.est.5b00553 VL - 49 IS - 20 SP - 12525-12534 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84945292175&partnerID=MN8TOARS ER - TY - JOUR TI - Using Agent-Based Modeling for Water Resources Planning and Management AU - Berglund, Emily Zechman T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - Agent-based systems have been developed for many scientific applications and simulation studies to model a group of actors and their interactions based on behavioral rules. Agent-based models and multiagent systems simulate the emergence of system-level properties based on the actions of adaptive agents that interact with other agents, react to environmental signals, and optimize decisions to achieve individual goals. In water resources planning and management, agent-based modeling has been applied to explore, simulate, and predict the performance of infrastructure design and policy decisions as they are influenced by human decision making, behaviors, and adaptations. The goal of this paper is to provide a comprehensive introduction to agent-based modeling for water resources researchers, students, and practitioners, and to explore water resources systems as complex adaptive systems that can be studied using agent-based modeling. Agent-based modeling is defined, and the characteristics of complex adaptive systems that necessitate its use are described. A literature review is presented to demonstrate research in the field that uses agent-based modeling to gain insight for water resources management. Two illustrative case studies of agent-based water resources systems models are developed and described. The case studies demonstrate the use of reactive and active (e.g., optimizing) agents for simulating water resources planning problems. The limitations in applying agent-based modeling and the insights that are expected from further investigations are summarized. DA - 2015/11// PY - 2015/11// DO - 10.1061/(asce)wr.1943-5452.0000544 VL - 141 IS - 11 SP - SN - 1943-5452 KW - Multi-agent systems KW - Complex adaptive systems KW - Coupled human and natural systems KW - Water management KW - Decision-making KW - Review ER - TY - JOUR TI - Social Network based sensitivity analysis for patient flow using computer simulation AU - Nikakhtar, Amin AU - Abbasian-Hosseini, S. Alireza AU - Gazula, Harshvardhan AU - Hsiang, Simon M. T2 - COMPUTERS & INDUSTRIAL ENGINEERING AB - Prediction of patient flow, an essential element of any healthcare system, is challenging due to uncertainties in patient volume. One such source of uncertainty is a propagated outbreak of epidemic diseases as they spread through networks of human populations. Till date, no study exists that studied the effect of social network structure on patient flow. In this study, we aim to examine the relationship between patient flow in a social network and the corresponding network characteristics. For this purpose, we developed a simulation model in which an epidemic spreads through a social network and then the generated patients are directed to a healthcare system. To quantify the patient flow, we considered the conditional expected value of the length of stay (LoS) as our performance measure. The network characteristics considered were average distance, closeness centralization, betweenness centralization, and eigenvector centralization. Results from this study indicate that the patient flow has a direct relationship with closeness centralization and an inverse relationship with average distance. Betweenness and eigenvector centralization did not provide any meaningful information in patient flow prediction. Overall, patient flow is more sensitive to average distance. This work helps healthcare planners and decision makers in better prediction of the patient flow during a propagated outbreak of an epidemic. DA - 2015/10// PY - 2015/10// DO - 10.1016/j.cie.2015.07.013 VL - 88 SP - 264-272 SN - 1879-0550 KW - Healthcare system KW - Patient flow KW - Computer simulation KW - Epidemic disease KW - Social network analysis KW - Sensitivity analysis ER - TY - JOUR TI - Performance evaluation of fog seals on chip seals and verification of fog seal field tests AU - Im, Jeong Hyuk AU - Kim, Y. Richard T2 - CANADIAN JOURNAL OF CIVIL ENGINEERING AB - With an increasing emphasis on pavement preservation treatments due to economic concerns over the high costs of paving materials, one of the most cost-effective pavement preservation treatments, chip seals, now constitutes a significant proportion of the pavement preservation treatments used in the North Carolina highway network. To mitigate a major problem with chip seals, i.e., the loose aggregate particles, fog seals, which are composed of an emulsified product placed on top of the chip seal, can be used to help control the loose aggregate. For this study, fog seals were applied on top of newly fabricated chip. The surface texture of the fog-sealed chip seals was analyzed using the British pendulum test and a three-dimensional laser. Also, fog seal field test methods that were developed to suggest appropriate traffic opening times after fog seal construction were verified. The main findings presented in this paper are that: (i) the use of polymer-modified emulsions improves fog seal performance in terms of better aggregate retention and bleeding resistance; (ii) the skid resistance problems are not evident once the fog seal is applied on the recommended chip seal type; (iii) the relationship between skid number and mean profile depth can be determined based on three trends that are dependent on traffic loadings, and (iv) although the fog seal field tests were unable to be completed due to safety concerns, it can nonetheless be recommended that approximately 60 min after fog seal construction is an appropriate traffic opening time. DA - 2015/11// PY - 2015/11// DO - 10.1139/cjce-2014-0340 VL - 42 IS - 11 SP - 872-880 SN - 1208-6029 KW - pavement preservation treatments KW - fog seal KW - polymer-modified emulsions (PMEs) KW - surface texture KW - field test methods ER - TY - JOUR TI - New generation of precast concrete double tees reinforced with carbon-fiber reinforced polymer grid AU - Lunn, Dillon AU - Lucier, Gregory AU - Rizkalla, Sami AU - Cleland, Ned AU - Gleich, Harry T2 - PCI Journal DA - 2015/7// PY - 2015/7// DO - 10.15554/pcij.07012015.37.48 VL - 60 IS - 4 SP - 37-48 J2 - pcij OP - SN - 0887-9672 UR - http://dx.doi.org/10.15554/pcij.07012015.37.48 DB - Crossref ER - TY - JOUR TI - Nanoindentation investigation of asphalt binder and mastic cohesion AU - Veytskin, Yuriy AU - Bobko, Christopher AU - Castorena, Cassie AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - A nanoindentation technique for determining the cohesive properties of neat, modified, and aged asphalt binders and mastics with varying filler volumetric concentrations is developed, tested, and verified. Cohesive properties of binder and mastic are critically important to the fracture resistance of asphalt concrete. A new approach to calculate and interpret important cohesive properties from nanoindentation data through low-load sphero-conical (blunt) nanoindentation is presented. Work of effective cohesion values are determined as the average response over multiple possible microstructures for three asphalt binders and 30 different mastics of varying filler volumetric concentrations. Results point to evidence of a critical filler volume fraction beyond which further addition of filler does not affect work of effective cohesion. This plateau in work of effective cohesion values is speculated to be related to the combined effects of volume-filling, particle interactions, and physicochemical interactions. The critical filler volumetric concentrations corresponding to the plateau in work of effective cohesion range between 0.20 and 0.30, which is within the range from literature of 0.15–0.30. Testing of binder and mastic through nanoindentation is an important step toward in situ testing of mastic within asphalt concrete, which is inaccessible using conventional macroscopic experimental methods. DA - 2015/12/15/ PY - 2015/12/15/ DO - 10.1016/j.conbuildmat.2015.09.053 VL - 100 SP - 163-171 SN - 1879-0526 KW - Nanoindentation KW - Cohesion KW - Asphalt KW - Binders KW - Mastics ER - TY - JOUR TI - Meeting multiple water quality objectives through treatment using locally generated char: improving organoleptic properties and removing synthetic organic contaminants and disinfection by-products AU - Kearns, Joshua P. AU - Shimabuku, Kyle K. AU - Mahoney, Ryan B. AU - Knappe, Detlef R. U. AU - Summers, R. Scott T2 - JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT AB - A variety of natural and anthropogenic contaminants can compromise the safety and esthetics of surface water collected for drinking and disinfected using chlorine by households in developing communities. While household chlorination is effective against most microbial pathogens, many users find the taste and odor of chlorine unacceptable and revert to drinking untreated water. Moreover, reactions between chlorine and the dissolved organic matter form harmful disinfection by-products (DBPs) such as trihalomethanes (THMs). Char adsorbers have been used to treat drinking water for thousands of years and are still widely used today. Results obtained here demonstrate that locally produced biomass chars (biochars) exhibit removal capacities comparable to those of activated carbon for removal of THMs, synthetic organic chemicals (SOCs) such as warfarin (WFN) (anticoagulant pharmaceutical, rodenticide), and naturally occurring trace organics such as the taste-and-odor compound 2-methylisoborneol (cyanobacterial metabolite). Results show chars can be used effectively to remove objectionable tastes and odors related to chlorine and cyanobacteria, DBPs, and SOCs. The use of char may lead to microbial risk reduction through greater acceptance of chlorine-based disinfection due to improved water esthetics, as well as chemical risk reduction associated with DBP and SOC exposure. DA - 2015/// PY - 2015/// DO - 10.2166/washdev.2015.172 VL - 5 IS - 3 SP - 359-372 SN - 2043-9083 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84940023189&partnerID=MN8TOARS KW - adsorption KW - biochar KW - charcoal KW - chemical water contaminants KW - point-of-use water treatment ER - TY - JOUR TI - Mapping the spatial distribution of the biomass and filter-feeding effect of invasive dreissenid mussels on the winter-spring phytoplankton bloom in Lake Michigan AU - Rowe, Mark D. AU - Obenour, Daniel R. AU - Nalepa, Thomas F. AU - Vanderploeg, Henry A. AU - Yousef, Foad AU - Kerfoot, W. Charles T2 - FRESHWATER BIOLOGY AB - Summary The effects of the invasive bivalves Dreissena polymorpha (zebra mussel) and Dreissena rostriformis bugensis (quagga mussel) on aquatic ecosystems, including Lake Michigan, are a topic of current interest to scientists and resource managers. We hypothesised that the winter–spring phytoplankton bloom in Lake Michigan is reduced at locations where the fraction of the water column cleared per day by Dreissena filter feeding approached the net growth rate of phytoplankton, when the water column was not stratified. To test this hypothesis, we compared the spatial distribution of Dreissena filter‐feeding intensity (determined from geostatistical modelling) to the spatial distribution of chlorophyll (determined from satellite remote sensing). To map the spatial distribution of Dreissena biomass and filter‐feeding intensity, we developed a geostatistical model based on point observations of mussel biomass measured in Lake Michigan in 1994/1995, 2000, 2005 and 2010. The model provided fine‐scale estimates of the spatial distribution of biomass for the survey years and provided estimates, with their uncertainty, of total biomass lakewide and within subregions. The approach outlined could be applied more generally to map the distribution of benthic biota in lakes from point observations. Total biomass of Dreissena in Lake Michigan, estimated from the geostatistical model, increased significantly over each five‐year period. The total biomass in units of 10 6 kg ash‐free dry mass ( AFDM ) (with 90% confidence interval) was 6 (4–8) in 1994/1995, 18 (14–23) in 2000, 408 (338–485) in 2005 and 610 (547–680) in 2010. From 1994/1995 to 2005, increases were observed in all regions of the lake (northern, central and southern) and in all depth zones (<30, 30–50, 50–90 and >90). However, from 2005 to 2010, for depths of <50 m, biomass declined in the northern region, remained constant in the central region and increased in the southern region; biomass continued to increase in all three lake regions for depths >50 m. The filter‐feeding intensity of Dreissena exceeded the benchmark spring phytoplankton growth rate of 0.06 day −1 in 2005 for depths <50 m (lakewide). In 2010, the filter‐feeding impact exceeded 0.06 day −1 within depths <90 m (lakewide), which greatly increased the spatial area affected relative to 2005. A regression analysis indicated a significant relationship between the reduction in satellite‐derived chlorophyll concentration (pre‐ D. r. bugensis period to post‐ D. r. bugensis period) and spatially co‐located filter‐feeding intensity (fraction of water column cleared per day) during periods when the water column was not stratified (December to April). DA - 2015/11// PY - 2015/11// DO - 10.1111/fwb.12653 VL - 60 IS - 11 SP - 2270-2285 SN - 1365-2427 KW - benthos KW - GIS KW - invasive species KW - invertebrates KW - lakes KW - modelling KW - physical environment KW - population KW - statistics ER - TY - JOUR TI - Feasibility of Using Traditional Kiln Charcoals in Low-Cost Water Treatment: Role of Pyrolysis Conditions on 2,4-D Herbicide Adsorption AU - Kearns, Joshua P. AU - Knappe, Detlef R. U. AU - Summers, R. Scott T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - Prior research has established that pyrolysis temperature during charcoal production is the primary variable influencing adsorption capacity. The first objective of this work was to monitor thermal conditions during charcoal production within three common traditional kiln models. Then, a programmable laboratory furnace pyrolyzer was used to generate chars from eucalyptus, pine, and longan woods and bamboo under a similar range of thermal conditions as identified in the field study. Using chars produced from the furnace, the second objective of this study was to investigate the influence of biomass feedstock and grain size, peak pyrolysis temperature, and duration of thermal treatment on 2,4-D herbicide sorption capacity. A third objective was to determine if chars produced in the laboratory furnace using thermal profiles similar to those observed in the horizontal drum kiln would exhibit similar adsorbent characteristics to kiln charcoals. Field observations revealed significant variability in temperature profiles during pyrolysis in traditional charcoal kilns, and laboratory experiments indicated corresponding variability in equilibrium 2,4-D uptake from surface water ranging from virtually no adsorption to around 10% of the adsorption capacity of commercial activated carbon. Increasing pyrolysis temperature or duration increased 2,4-D adsorption capacity, whereas feedstock did not affect adsorption capacity for the materials studied. Similar herbicide adsorption capacity was observed for furnace chars and kiln charcoals generated using similar thermal profiles. The difficulty of achieving precise temperature control with traditional charcoal production systems contributes to wide thermal variability within and between batches, which translates to wide variability in adsorption of organic compounds. DA - 2015/11/1/ PY - 2015/11/1/ DO - 10.1089/ees.2015.0243 VL - 32 IS - 11 SP - 912-921 SN - 1557-9018 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946830926&partnerID=MN8TOARS KW - 2,4-D KW - adsorption KW - biochar KW - charcoal KW - decentralized water treatment KW - engineering for developing communities KW - low cost adsorbents ER - TY - JOUR TI - Effect of MDOF structures' optimal dampers on seismic fragility of piping AU - Jung, W. Y. AU - Ju, B. S. T2 - Earthquakes and Structures DA - 2015/// PY - 2015/// VL - 9 IS - 3 SP - 563-576 ER - TY - JOUR TI - Effect of Damage on Moisture Transport in Concrete AU - Ghasemzadeh, Farnam AU - Pour-Ghaz, Mohammad T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - This paper presents the results of an experimental and analytical study on the effect of distributed cracks (damage) on moisture transport in concrete. Specifically, the writers investigate the following: (1) how damage affects the saturated and unsaturated transport and electrical resistivity, (2) whether one-dimensional (1D) analysis based on the sharp front (SF) theory can explain the relation between the saturated and unsaturated transport in damaged concrete, and (3) which transport mechanism is more sensitive to damage. Conceptual models are developed based on damage mechanics and fluid transport to explain the experimental data. Material constants are also provided for numerical modeling of unsaturated transport in damaged concrete. The results show that damage differently affects each of the transport mechanisms, and saturated hydraulic conductivity is more sensitive to damage as compared to sorptivity and electrical resistivity. The simplified 1D analysis, based on the sharp front theory, does not adequately describe the effect of damage on unsaturated transport. The developed conceptual models can be used to qualitatively describe the effect of damage on transport properties of concrete. DA - 2015/9// PY - 2015/9// DO - 10.1061/(asce)mt.1943-5533.0001211 VL - 27 IS - 9 SP - SN - 1943-5533 KW - Concrete KW - Cracking KW - Damage KW - Damage detection KW - Damage mechanics KW - Durability KW - Freeze-thaw KW - Moisture transport ER - TY - JOUR TI - Complex Adaptive Modeling Framework for Evaluating Adaptive Demand Management for Urban Water Resources Sustainability AU - Giacomoni, M. H. AU - Berglund, E. Z. T2 - Journal of Water Resources Planning and Management AB - New water resources management methodologies are needed to address increasing demands and future uncertainty for urban water resources. Adaptive water demand management strategies provide an approach to improve the efficiency of water system operations and meet water demands by adapting flexibility to increasing stresses, such as droughts. This study simulates adaptive water demand management through the development of a complex adaptive system modeling framework, which couples cellular automata modeling, agent-based modeling, and hydrologic modeling to simulate land-use change, consumer behaviors, management decisions, the rainfall-runoff process, and reservoir storage. The model is applied to simulate the effect of demand management strategies on reductions in municipal water demands and on the sustained storage in a surface water supply reservoir. Historic and projected climate change hydroclimatic time series are used to assess the effectiveness of domestic water restrictions, including outdoor watering restrictions, a rainwater harvesting rebate program, and a high-density land-use change policy. Strategies are adaptively implemented based on the amount of water storage available. The framework is applied to evaluate strategies for the Arlington, Texas, metropolitan area that historically suffers from severe droughts. The framework provides an approach to evaluate a combination of multiple strategies for effectively managing the increasing stresses caused by urbanization, population growth, and climate change. Results demonstrate that adaptive demand management strategies that respond to water shortages result in long-term per capita demand reductions. For climate projections that forecast severe water shortages, development density strategies are more effective than rainwater harvesting strategies, and a combination of strategies can reduce the need for interbasin transfers and maintain reservoir volumes. DA - 2015/11// PY - 2015/11// DO - 10.1061/(asce)wr.1943-5452.0000543 VL - 141 IS - 11 SP - 04015024 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(ASCE)WR.1943-5452.0000543 DB - Crossref KW - Adaptive management KW - Demand management KW - Drought management KW - Water resources sustainability KW - Complex adaptive systems ER - TY - JOUR TI - Clustering and Differential Alignment Algorithm: Identification of Early Stage Regulators in the Arabidopsis thaliana Iron Deficiency Response AU - Koryachko, Alexandr AU - Matthiadis, Anna AU - Muhammad, Durreshahwar AU - Foret, Jessica AU - Brady, Siobhan M. AU - Ducoste, Joel J. AU - Tuck, James AU - Long, Terri A. AU - Williams, Cranos T2 - PLOS ONE AB - Time course transcriptome datasets are commonly used to predict key gene regulators associated with stress responses and to explore gene functionality. Techniques developed to extract causal relationships between genes from high throughput time course expression data are limited by low signal levels coupled with noise and sparseness in time points. We deal with these limitations by proposing the Cluster and Differential Alignment Algorithm (CDAA). This algorithm was designed to process transcriptome data by first grouping genes based on stages of activity and then using similarities in gene expression to predict influential connections between individual genes. Regulatory relationships are assigned based on pairwise alignment scores generated using the expression patterns of two genes and some inferred delay between the regulator and the observed activity of the target. We applied the CDAA to an iron deficiency time course microarray dataset to identify regulators that influence 7 target transcription factors known to participate in the Arabidopsis thaliana iron deficiency response. The algorithm predicted that 7 regulators previously unlinked to iron homeostasis influence the expression of these known transcription factors. We validated over half of predicted influential relationships using qRT-PCR expression analysis in mutant backgrounds. One predicted regulator-target relationship was shown to be a direct binding interaction according to yeast one-hybrid (Y1H) analysis. These results serve as a proof of concept emphasizing the utility of the CDAA for identifying unknown or missing nodes in regulatory cascades, providing the fundamental knowledge needed for constructing predictive gene regulatory networks. We propose that this tool can be used successfully for similar time course datasets to extract additional information and infer reliable regulatory connections for individual genes. DA - 2015/8/28/ PY - 2015/8/28/ DO - 10.1371/journal.pone.0136591 VL - 10 IS - 8 SP - SN - 1932-6203 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84943338816&partnerID=MN8TOARS ER - TY - JOUR TI - Multicriteria assessment of crosswalk location in urban roundabout corridors AU - Fernandes, P. AU - Fontes, T. AU - Pereira, S. R. AU - Rouphail, N. M. AU - Coelho, M. C. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2517 SP - 37-47 ER - TY - JOUR TI - Measurement and Evaluation of Real-World Speed and Acceleration Activity Envelopes for Light-Duty Vehicles AU - Liu, Bin AU - Frey, H. Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - Accurate estimation of vehicle activity is critically important for the accurate estimation of emissions. To provide a benchmark for estimation of vehicle speed trajectories such as those from traffic simulation models, this paper demonstrates a method for quantifying light-duty vehicle activity envelopes based on real-world activity data for 100 light-duty vehicles, including conventional passenger cars, passenger trucks, and hybrid electric vehicles. The vehicle activity envelope was quanti-fied in the 95% frequency range of acceleration for each of 15 speed bins with intervals of 5 mph and a speed bin for greater than 75 mph. Potential factors affecting the activity envelope were evaluated; these factors included vehicle type, transmission type, road grade, engine displacement, engine horsepower, curb weight, and ratio of horsepower to curb weight. The activity envelope was wider for speeds ranging from 5 to 20 mph and narrowed as speed increased. The latter was consistent with a constraint on maximum achievable engine power demand. The envelope was weakly sensitive to factors such as type of vehicle, type of transmission, road grade, and engine horsepower. The effect of road grade on cycle average emissions rates was evaluated for selected real-word cycles. The measured activity envelope was compared with those of dynamometer driving cycles, such as the federal test procedure, highway fuel economy test, SC03, and US06 cycles. The effect of intervehicle variability on the activity envelope was minor; this factor implied that the envelope could be quantified based on a smaller vehicle sample than used for this study. DA - 2015/// PY - 2015/// DO - 10.3141/2503-14 VL - 2503 IS - 2503 SP - 128-136 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85137320390&partnerID=MN8TOARS ER - TY - JOUR TI - Improved reservoir sizing utilizing observed and reconstructed streamflows within a Bayesian combination framework AU - Patskoski, Jason AU - Sankarasubramanian, A. T2 - Water Resources Research AB - Abstract Reservoir sizing is a critical task as the storage in a reservoir must be sufficient to supply water during extended droughts. Typically, sequent peak algorithm (SQP) is used with observed streamflow to obtain reservoir storage estimates. To overcome the limited sample length of observed streamflow, synthetic streamflow traces estimated from observed streamflow characteristics are provided with SQP to estimate the distribution of storage. However, the parameters in the stochastic streamflow generation model are derived from the observed record and are still unrepresentative of the long‐term drought records. Paleo‐streamflow time series, usually reconstructed using tree‐ring chronologies, span for a longer period than the observed streamflow and provide additional insight into the preinstrumental drought record. This study investigates the capability of reconstructed streamflow records in reducing the uncertainty in reservoir storage estimation. For this purpose, we propose a Bayesian framework that combines observed and reconstructed streamflow for estimating the parameters of the stochastic streamflow generation model. By utilizing reconstructed streamflow records from two potential stations over the Southeastern U.S., the distribution of storage estimated using the combined streamflows is compared with the distribution of storage estimated using observed streamflow alone based on split‐sample validation. Results show that combining observed and reconstructed streamflow yield stochastic streamflow generation parameters more representative of the longer streamflow record resulting in improved reservoir storage estimates. We also generalize the findings through a synthetic experiment by generating reconstructed streamflow records of different sample length and skill. The analysis shows that uncertainty in storage estimates reduces by incorporating reconstruction records with higher skill and longer sample lengths. Potential applications of the proposed methodology are also discussed. DA - 2015/7// PY - 2015/7// DO - 10.1002/2014wr016189 VL - 51 IS - 7 SP - 5677–5697 SN - 0043-1397 1944-7973 UR - http://dx.doi.org/10.1002/2014WR016189 KW - tree rings KW - reservoir sizing KW - sequent peak algorithm KW - storage-reliability-yield curves KW - ENSO ER - TY - JOUR TI - Implications of physico-chemical interactions in asphalt mastics on asphalt microstructure AU - Davis, Chelsea AU - Castorena, Cassie T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Asphalt binder and filler blend to form asphalt mastic, which constitutes the effective adhesive film in asphalt concrete. Pavement performance can be improved through better engineering of the mastic, which requires a fundamental understanding of the interaction between asphalt and filler. Physico–chemical interactions result in adsorption of polar fractions of the asphalt onto filler surfaces, leading to the formation of an interphase layer on the surface of particles and modifying the asphalt binder matrix. This study seeks to investigate the effects of physico–chemical interaction on binder matrix microstructure using Atomic Force Microscopy (AFM) and qualitatively relate microstructural findings to macroscopic rheology. DA - 2015/9/30/ PY - 2015/9/30/ DO - 10.1016/j.conbuildmat.2015.06.026 VL - 94 SP - 83-89 SN - 1879-0526 KW - Asphalt KW - Mastic KW - Physico-chemical interaction KW - Microstructure KW - Atomic Force Microscopy ER - TY - JOUR TI - Experimental and Numerical Investigation of the FRP Shear Mechanism for Concrete Sandwich Panels AU - Hodicky, K. AU - Sopal, G. AU - Rizkalla, S. AU - Hulin, T. AU - Stang, H. T2 - JOURNAL OF COMPOSITES FOR CONSTRUCTION AB - This paper investigates the composite action of 46 segments representing precast concrete sandwich panels (PCSPs) using a fiber-reinforced polymer [FRP; specifically, a carbon fiber–reinforced polymer (CFRP)] grid/rigid foam as a shear mechanism. The experimental aspect of the research reported in this paper examined the effect of various parameters believed to affect the shear flow strength for this CFRP grid/foam system. The parameters that were considered are the spacing between vertical lines of CFRP grids and the thickness of the rigid foam. Results of the experimental aspect of the research reported in this paper indicated that increasing the spacing between vertical lines of CFRP grid increase the overall shear flow strengths due to the increase of the bonded contact area of the rigid foam to the concrete surface. However, the overall shear stresses were decreased due to the increase of this interface surface area. Test results also indicated that increasing the rigid foam thickness decreases the overall shear flow strength when compared with the same quantity of CFRP grid spacing. A nonlinear three-dimensional (3D) FEM analysis was performed to model the behavior of the tested segments and to study the behavior of PCSPs. Results of FEM analysis were in good agreement with the experimental results. A design equation was developed to determine the shear flow strengths for the given CFRP grid/foam systems. The parametric study of the research reported in this paper was performed to predict shear flow strength of different FRP materials, rigid foam thickness, and spacing between vertical lines of the grid. DA - 2015/10// PY - 2015/10// DO - 10.1061/(asce)cc.1943-5614.0000554 VL - 19 IS - 5 SP - SN - 1943-5614 KW - Concrete sandwich panel KW - Nonlinear analysis KW - Finite-element analysis KW - Carbonfiber-reinforced polymer KW - Shear test KW - Bond-slip behavior ER - TY - JOUR TI - Decomposition and carbon storage of selected paper products in laboratory-scale landfills AU - Wang, Xiaoming AU - Cruz, Florentino B. AU - Ximenes, Fabiano AU - Barlaz, Morton A. T2 - SCIENCE OF THE TOTAL ENVIRONMENT AB - The objective of this study was to measure the anaerobic biodegradation of different types of paper products in laboratory-scale landfill reactors. The study included (a) measurement of the loss of cellulose, hemicellulose, organic carbon, and (b) measurement of the methane yields for each paper product. The test materials included two samples each of newsprint (NP), copy paper (CP), and magazine paper (MG), and one sample of diaper (DP). The methane yields, carbon storage factors and the extent of cellulose and hemicellulose decomposition all consistently show that papers made from mechanical pulps (e.g., NPs) are less degradable than those made from chemical pulps where essentially all lignin was chemically removed (e.g., CPs). The diaper, which is not only made from chemical pulp but also contains some gel and plastic, exhibited limited biodegradability. The extent of biogenic carbon conversion varied from 21 to 96% among papers, which contrasts with the uniform assumption of 50% by the Intergovernmental Panel on Climate Change (IPCC) for all degradable materials discarded in landfills. Biochemical methane potential tests also showed that the solids to liquid ratio used in the test can influence the results. DA - 2015/11/1/ PY - 2015/11/1/ DO - 10.1016/j.scitotenv.2015.05.132 VL - 532 SP - 70-79 SN - 1879-1026 KW - Landfills KW - Municipal solid waste KW - Paper products KW - Anaerobic decomposition KW - Biochemical methane potential KW - Carbon storage ER - TY - JOUR TI - Assessment of corridors with different types of intersections environmental and traffic performance analysis AU - Fernandes, P. AU - Fontes, T. AU - Neves, M. AU - Pereira, S. R. AU - Bandeira, J. M. AU - Rouphail, N. M. AU - Coelho, M. C. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2503 SP - 39-50 ER - TY - JOUR TI - Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, during Simulated Vomiting AU - Tung-Thompson, Grace AU - Libera, Dominic A. AU - Koch, Kenneth L. AU - de los Reyes, Francis L. AU - Jaykus, Lee-Ann T2 - PLOS ONE AB - Human noroviruses (NoV) are the leading cause of acute gastroenteritis worldwide. Epidemiological studies of outbreaks have suggested that vomiting facilitates transmission of human NoV, but there have been no laboratory-based studies characterizing the degree of NoV release during a vomiting event. The purpose of this work was to demonstrate that virus aerosolization occurs in a simulated vomiting event, and to estimate the amount of virus that is released in those aerosols. A simulated vomiting device was constructed at one-quarter scale of the human body following similitude principles. Simulated vomitus matrices at low (6.24 mPa*s) and high (177.5 mPa*s) viscosities were inoculated with low (108 PFU/mL) and high (1010 PFU/mL) concentrations of bacteriophage MS2 and placed in the artificial “stomach” of the device, which was then subjected to scaled physiologically relevant pressures associated with vomiting. Bio aerosols were captured using an SKC Biosampler. In low viscosity artificial vomitus, there were notable differences between recovered aerosolized MS2 as a function of pressure (i.e., greater aerosolization with increased pressure), although this was not always statistically significant. This relationship disappeared when using high viscosity simulated vomitus. The amount of MS2 aerosolized as a percent of total virus “vomited” ranged from 7.2 x 10-5 to 2.67 x 10-2 (which corresponded to a range of 36 to 13,350 PFU total). To our knowledge, this is the first study to document and measure aerosolization of a NoV surrogate in a similitude-based physical model. This has implications for better understanding the transmission dynamics of human NoV and for risk modeling purposes, both of which can help in designing effective infection control measures. DA - 2015/8/19/ PY - 2015/8/19/ DO - 10.1371/journal.pone.0134277 VL - 10 IS - 8 SP - e0134277 J2 - PLoS ONE LA - en OP - SN - 1932-6203 UR - http://dx.doi.org/10.1371/journal.pone.0134277 DB - Crossref ER - TY - JOUR TI - Simplified method for comparing emissions in roundabouts and at signalized intersections AU - Salamati, K. AU - Rouphail, N.M. AU - Frey, H.C. AU - Liu, B. AU - Schroeder, B.J. T2 - Transportation Research Record AB - An empirically based macroscopic method is presented. It estimates and compares the pollutant emissions generated from signalized intersections and roundabouts. This method was built on a large sample size of real-world second-by-second vehicle trajectories, traffic volumes, and other traffic characteristics collected at signalized intersections and roundabouts in six U.S. states. The basis for predicting and estimating pollutant emissions was the concept of vehicle-specific power. The method enables inclusion of emissions standards and vehicle classes, such as Tier 1 (T1) and Tier 2 (T2) passenger cars (PCs) and passenger trucks (PTs). More than 1,980 vehicle trajectories were analyzed. Traffic variables including intersection capacity, demand-to-capacity ratio ( d/ c), cycle length, green-to-cycle length ratio, signal progression (i.e., arrival type), and number of lanes were included in the model for analysis and comparison between signals and roundabouts. Application of the method to a case study showed that on average under low d/ c (<0.7), roundabouts generated lower emission rates than signalized intersections. As demand approached capacity under high traffic volumes, signalized intersections with favorable progression (i.e., most demand arrived during green phase) generally produced lower emission rates than roundabouts. Signalized intersections with poor progression (i.e., most demand arrived during red phase) generated more emissions than roundabouts. Results also showed that during oversaturation periods (when d/ c > 1), the amount of produced emissions increased steadily in roundabouts but increased a large amount at signals. DA - 2015/// PY - 2015/// DO - 10.3141/2517-06 VL - 2517 IS - 2517 SP - 48-60 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975815213&partnerID=MN8TOARS ER - TY - JOUR TI - Planning-Level Methodology for Freeway Facilities AU - Hajbabaie, Ali AU - Rouphail, Nagui M AU - Schroeder, Bastian J AU - Dowling, Richard T2 - Transportation Research Record AB - This paper presents a planning-level methodology for the analysis of freeway facilities. The proposed approach is based on and compatible with the operational method of the Highway Capacity Manual 2010 (HCM 2010). The approach is specifically constructed with the intent to minimize input data requirements. The method covers both under- and oversaturated flow conditions and produces estimates of travel time, speed, density, and level of service. The underlying methodology relies on developing a relationship between a basic freeway segment's delay rate per unit distance and its demand-to-capacity ratio. For weaving segments, the study develops capacity adjustment factors on the basis of volume ratio and segment length. With these factors, demand-to-capacity ratios on weave segments were adjusted and the segment was treated similarly to a basic freeway segment. For merge and diverge segments, a novel methodology is proposed to estimate their capacity on the basis of demand level, free-flow speed, and space mean speed. Subsequently, capacity adjustment factors are calculated on those segments and their demand-to-capacity ratios are adjusted accordingly. The proposed approach is applied to two examples in the HCM 2010 and produced very promising results. For undersaturated flow conditions, facility travel time is at most 3.4% and density was at most 1.1% at variance from the results found by applying the HCM 2010 operational methodology. The corresponding differences for oversaturated conditions are 6.7% and 13.0%, respectively. DA - 2015/// PY - 2015/// DO - 10.3141/2483-06 VL - 2483 IS - 1 SP - 47-56 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975682966&partnerID=MN8TOARS ER - TY - JOUR TI - On the Treatment of Trucks in Roundabout Analyses AU - List, George F. AU - Yang, Bo AU - Schroeder, Bastian J. T2 - TRANSPORTATION RESEARCH RECORD AB - Trucks are not always addressed explicitly in planning studies and operational analyses, even though they are a very important part of the nation's economic engine. Most planning studies account for trucks as a percentage of the total traffic flow. The Highway Capacity Manual (HCM) converts trucks into autos through the use of a passenger car equivalency (PCE) factor. If the PCE is 2, then a truck is assumed to be equivalent to two autos. However, trucks are beginning to receive more attention, including that in the context of capacity assessments. A recent research effort focused on developing a level-of-service assessment for trucks and for enhancing the way that the impact of trucks is taken into account on freeways, arterials, and roundabouts. This paper focuses on the roundabout aspects of that research. The three roundabout-related objectives in the project were (a) to refine the PCE values used to convert trucks into auto equivalents for the flow on roundabout approaches, (b) to recalibrate the capacity equation so that it more appropriately accounts for trucks, and (c) to develop ways to estimate truck speeds so that travel times through the roundabout could be computed. The results of these analyses are presented as well as the methodology and data employed. DA - 2015/// PY - 2015/// DO - 10.3141/2483-16 IS - 2483 SP - 140-147 SN - 2169-4052 ER - TY - JOUR TI - On the Treatment of Trucks for Analysis of Freeway Capacity AU - List, George F. AU - Yang, Bo AU - Rouphail, Nagui M. T2 - TRANSPORTATION RESEARCH RECORD AB - The influence of trucks on highway performance has always been of interest. However, planning studies today tend to assume that a certain percentage of the traffic stream is trucks (e.g., 5%) and to make adjustments accordingly. The Highway Capacity Manual (HCM) converts trucks into passenger car equivalents by using a passenger car equivalent factor. For the HCM, however, this situation is changing. This paper describes changes to the basic freeway section methodology that are being developed to better address truck-related issues. Specifically, new models predict the space mean speeds of autos and trucks in mixed traffic streams for a variety of road grades. Also presented is a capacity adjustment factor that allows conversion of capacity values for auto-only conditions to be transformed into equivalent capacity values for mixed traffic conditions. The methodologies are presented, their development is described, and examples are given to illustrate how the procedure works. DA - 2015/// PY - 2015/// DO - 10.3141/2483-14 IS - 2483 SP - 120-129 SN - 2169-4052 ER - TY - JOUR TI - New small-diameter CFRP material for flexural strengthening of steel bridge girders AU - Tabrizi, Salar AU - Kazem, Hamid AU - Rizkalla, Sami AU - Kobayashi, Akira T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper presents the research findings of an experimental program undertaken to examine the effectiveness of using small-diameter CFRP strands to increase the flexural capacity of steel beams and bridge girders. The experimental program included scaled steel-concrete composite beams, strengthened with these small-diameter strands. The CFRP strands were stitched together with a gap between the strands to allow the adhesive to penetrate and cover the entire perimeter of each strand. Results showed that the proposed system eliminated failure due to de-bonding of the strengthening materials and significantly increased the flexural capacity and stiffness of steel beams. DA - 2015/10/1/ PY - 2015/10/1/ DO - 10.1016/j.conbuildmat.2015.07.109 VL - 95 SP - 748-756 SN - 1879-0526 KW - Small-diameter CFRP strands KW - Steel KW - Flexure KW - Strengthening ER - TY - JOUR TI - Methodology to compute travel time of a roundabout corridor AU - Bugg, Z. AU - Schroeder, B. J. AU - Jenior, P. AU - Brewer, M. AU - Rodegerdts, L. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2483 SP - 20-29 ER - TY - JOUR TI - Innovative work zone capacity models from nationwide field and archival sources AU - Yeom, Chunho AU - Hajbabaie, Ali AU - Schroeder, Bastian J AU - Vaughan, Christopher AU - Xuan, Xingyu AU - Rouphail, Nagui M T2 - Transportation Research Record AB - Freeway work zone capacity has been the focus of significant research, but most studies were limited to specific geographic regions or work zone configurations or both. To date, no work zone predictive capacity model exists for U.S. freeways that is based on a geographically representative data set or sensitive to key geometric and operational attributes of the work zone. This paper proposes a new capacity model for freeway work zones, developed from nationwide field data fused with data obtained from an in-depth review of archived literature of prior work zone capacity studies in the United States. The proposed model estimates work zone capacity as a function of the lane closure severity index, barrier type, area type, lateral clearances, and daytime or nighttime work conditions. The model was successfully validated with 25% of the combined data that were not used for the model development. In addition, findings from literature archives suggested a 13.4% difference between prebreakdown, uninterrupted capacity and the ensuing queue discharge rate. The developed capacity model is intended to be incorporated into the next release of the Highway Capacity Manual and provides important insights on the relative effects of work zone configuration and other variables on the expected capacity of freeway work zones. DA - 2015/// PY - 2015/// DO - 10.3141/2485-07 VL - 2485 IS - 1 SP - 51-60 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975853844&partnerID=MN8TOARS ER - TY - JOUR TI - Hydrodynamic Instability Mechanism for Rip Currents AU - Yu, Jie AU - Chen, Siyu T2 - STUDIES IN APPLIED MATHEMATICS AB - On reexamining the hydrodynamic instability, Yu [1] showed that when the fully dynamical interactions are duly accounted for, and proper mathematical analysis is carried out, the positive feedback between the wave and evolving current can initiate and sustain rip current circulations with scales comparable to field observations on alongshore uniform beaches. In this study, we extend that analysis to consider nonplanar beaches, and to include a new branch of unstable modes that correspond to alongshore propagating horizontal circulations with the magnitudes of the flow growing in time. The latter has not previously been studied. These propagating unstable modes have typical time periods of tens of minutes and alongshore propagation speeds of a few centimeters per second. The physical implications of their spatial and slow time oscillations are discussed, as of relevance to occurrence and recurrence of transient rips, alongshore migration of rip currents and very low frequency pulsations in surf zone eddy circulations. DA - 2015/8// PY - 2015/8// DO - 10.1111/sapm.12074 VL - 135 IS - 2 SP - 196-223 SN - 1467-9590 ER - TY - JOUR TI - Heuristic optimization of a continuous flow point-of-use UV-LED disinfection reactor using computational fluid dynamics AU - Jenny, Richard M. AU - Jasper, Micah N. AU - Simmons, Otto D., III AU - Shatalov, Max AU - Ducoste, Joel J. T2 - WATER RESEARCH AB - Alternative disinfection sources such as ultraviolet light (UV) are being pursued to inactivate pathogenic microorganisms such as Cryptosporidium and Giardia, while simultaneously reducing the risk of exposure to carcinogenic disinfection by-products (DBPs) in drinking water. UV-LEDs offer a UV disinfecting source that do not contain mercury, have the potential for long lifetimes, are robust, and have a high degree of design flexibility. However, the increased flexibility in design options will add a substantial level of complexity when developing a UV-LED reactor, particularly with regards to reactor shape, size, spatial orientation of light, and germicidal emission wavelength. Anticipating that LEDs are the future of UV disinfection, new methods are needed for designing such reactors. In this research study, the evaluation of a new design paradigm using a point-of-use UV-LED disinfection reactor has been performed. ModeFrontier, a numerical optimization platform, was coupled with COMSOL Multi-physics, a computational fluid dynamics (CFD) software package, to generate an optimized UV-LED continuous flow reactor. Three optimality conditions were considered: 1) single objective analysis minimizing input supply power while achieving at least (2.0) log10 inactivation of Escherichia coli ATCC 11229; and 2) two multi-objective analyses (one of which maximized the log10 inactivation of E. coli ATCC 11229 and minimized the supply power). All tests were completed at a flow rate of 109 mL/min and 92% UVT (measured at 254 nm). The numerical solution for the first objective was validated experimentally using biodosimetry. The optimal design predictions displayed good agreement with the experimental data and contained several non-intuitive features, particularly with the UV-LED spatial arrangement, where the lights were unevenly populated throughout the reactor. The optimal designs may not have been developed from experienced designers due to the increased degrees of freedom offered by using UV-LEDs. The results of this study revealed that the coupled optimization routine with CFD was effective at significantly decreasing the engineer's design decision space and finding a potentially near-optimal UV-LED reactor solution. DA - 2015/10/15/ PY - 2015/10/15/ DO - 10.1016/j.watres.2015.06.031 VL - 83 SP - 310-318 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84938590485&partnerID=MN8TOARS KW - Drinking water disinfection KW - UV Light Emitting Diodes KW - Numerical model KW - Numerical optimization KW - Biodosimetry ER - TY - JOUR TI - Generic Speed--Flow Models for Basic Freeway Segments on General-Purpose and Managed Lanes in Undersaturated Flow Conditions AU - Aghdashi, Seyedbehzad AU - Rouphail, Nagui M AU - Hajbabaie, Ali AU - Schroeder, Bastian J T2 - Transportation Research Record DA - 2015/// PY - 2015/// VL - 2483 IS - 1 SP - 102-110 ER - TY - JOUR TI - Generating Scenarios of Freeway Reliability Analysis: Hybrid Approach AU - Aghdashi, S. AU - Hajbabaie, A. AU - Rouphail, N.M. AU - Schroeder, B.J. AU - Trask, J.L. T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The freeway reliability methodology proposed for the Highway Capacity Manual, which is based on SHRP2 L08 methodology, produces an approach to scenario generation that can result in several thousand scenarios to be evaluated to estimate travel time reliability. This large number of scenarios can result in cumbersome user input, a demanding computational burden, and more important, extensive challenges posed when trying to error-check and interpret individual scenarios or to calibrate the model on the basis of real-world observations. This paper presents a novel scenario-generating methodology that accounts for multiple operating conditions. The objective of the proposed approach is to increase the quality of each scenario to make it more representative of the expected congestion patterns on the freeway. This paper shows that the new approach estimates reliability performance measures more accurately than current methods, while reducing the number of scenarios significantly. Thus, the new approach results in a more direct interpretation of results, while simultaneously relaxing many assumptions in the present approach to scenario generation and decreasing biases and errors. The proposed approach uses three core mathematical schemes: (a) a deterministic mathematical model for demand generation and scheduled work zones, (b) a Monte Carlo simulation for incident and weather events, and (c) an optimization algorithm to maximize similarities between the generated set of scenarios and the population of all scenarios. A comparison of results between the proposed method and the SHRP 2 Project L08 approach confirms that the proposed approach yields a higher level of accuracy in matching observed freeway reliability performance measures. DA - 2015/// PY - 2015/// DO - 10.3141/2483-17 VL - 2483 IS - 1 SP - 148-159 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84975722795&partnerID=MN8TOARS ER - TY - JOUR TI - Comparison of Over-the-Rail and Rail Yard Measurements of Diesel Locomotives AU - Graver, Brandon M. AU - Frey, H. Christopher T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Locomotive prime mover engine emission rates are typically measured at steady-state for discrete throttle notches using an engine dynamometer weighted by a standard duty cycle. However, this method may not represent real-world locomotive emissions. A method for in-use measurement of passenger locomotives, using a portable emissions measurement system (PEMS), was developed to estimate duty cycle average emission rates. We conducted 48 measurements of one-way trips between Raleigh and Charlotte, NC, on 7 locomotives and 18 sets of measurements in the rail yard (RY). Real-world duty cycles differed from those used for regulatory analyses, leading to statistically significant lower cycle average NOx and HC emission rates. Compared to RY measurements, notch average NOx emission rates measured over-the-rail (OTR) at the highest two notch settings were, on average, 19% lower for four locomotives. At the highest notch, OTR CO2 emission rates were, on average, 12% lower than RY rates for five locomotives. For a more accurate representation of real-world emission rates, OTR measurements are preferred. However, using steady-state notch average RY emission rates and standard duty cycles may be tolerable for some applications. OTR versus RY cycle average emission rates typically differed by less than 10%. DA - 2015/11/3/ PY - 2015/11/3/ DO - 10.1021/acs.est.5b02497 VL - 49 IS - 21 SP - 13031-13039 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84946601235&partnerID=MN8TOARS ER - TY - JOUR TI - A techno-economic assessment of offshore wind coupled to offshore compressed air energy storage AU - Li, B. H. AU - DeCarolis, J. F. T2 - Applied Energy AB - A critical challenge associated with renewable energy is managing its variable and intermittent output. Offshore compressed air energy storage (OCAES) is a carbon-free storage technology that can used to support renewable energy generation in marine environments. This paper provides the first economic characterization of OCAES performance when coupled to an offshore wind farm by employing a mixed integer programming model. The model seeks the minimum levelized cost of electricity by optimizing the grid-tied cable capacity and OCAES component sizes across a range of specified cable capacity factors. OCAES can be used to increase the capacity factor of the grid-tied transmission cable, but the resultant levelized cost of electricity strongly depends on the OCAES cost assumptions. Compared to using a land-based gas turbine as backup, OCAES is significantly more expensive, even when the price of carbon exceeds 1000 $/tC. DA - 2015/// PY - 2015/// DO - 10.1016/j.apenergy.2015.05.111 VL - 155 SP - 315-322 ER - TY - JOUR TI - A German approach to freeway facility evaluation AU - Hartmann, M. AU - Vortisch, P. AU - Schroeder, B. J. T2 - Transportation Research Record DA - 2015/// PY - 2015/// IS - 2483 SP - 66-73 ER - TY - JOUR TI - Untitled AU - Gabr, Mo T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING DA - 2015/8// PY - 2015/8// DO - 10.1061/(asce)gt.1943-5606.0001369 VL - 141 IS - 8 SP - SN - 1943-5606 ER - TY - JOUR TI - The decay of wood in landfills in contrasting climates in Australia AU - Ximenes, Fabiano AU - Bjordal, Charlotte AU - Cowie, Annette AU - Barlaz, Morton T2 - WASTE MANAGEMENT AB - Wood products in landfill are commonly assumed to decay within several decades, returning the carbon contained therein to the atmosphere, with about half the carbon released as methane. However, the rate and extent of decay is not well known, as very few studies have examined the decay of wood products in landfills. This study reports on the findings from landfill excavations conducted in the Australian cities of Sydney and Cairns located in temperate and tropical environments, respectively. The objective of this study was to determine whether burial of the wood in warmer, more tropical conditions in Cairns would result in greater levels of decay than occurs in the temperate environment of Sydney. Wood samples recovered after 16–44 years in landfill were examined through physical, chemical and microscopic analyses, and compared with control samples to determine the carbon loss. There was typically little or no decay in the wood samples analysed from the landfill in Sydney. Although there was significant decay in rainforest wood species excavated from Cairns, decay levels for wood types that were common to both Cairns and Sydney landfills were similar. The current Intergovernmental Panel on Climate Change (IPCC, 2006) default decay factor for organic materials in landfills is 50%. In contrast, the carbon loss determined for Pinus radiata recovered from Sydney and Cairns landfills was 7.9% and 4.4%, respectively, and 0% for Agathis sp. This suggests that climate did not influence decay, and that the more extensive levels of decay observed for some wood samples from Cairns indicates that those wood types were more susceptible to biodegradation. Microscopic analyses revealed that most decay patterns observed in samples analysed from Sydney were consistent with aerobic fungal decay. Only a minor portion of the microbial decay was due to erosion bacteria active in anaerobic/near anaerobic environments. The findings of this study strongly suggest that models that adopt current accepted default factors for the decay of wood in landfills greatly overestimate methane emissions. DA - 2015/7// PY - 2015/7// DO - 10.1016/j.wasman.2015.03.032 VL - 41 SP - 101-110 SN - 0956-053X KW - Wood KW - Decay KW - Landfill KW - Climate KW - Carbon KW - Methane ER - TY - JOUR TI - Stress-Strain Behavior of Sands Cemented by Microbially Induced Calcite Precipitation AU - Montoya, B. M. AU - DeJong, J. T. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING AB - Microbial induced calcite precipitation (MICP) is a novel biomediated ground improvement method that can be used to increase the shear strength and stiffness of soil. The evolution of the shear strength and stiffness of sand subjected to undrained and drained shearing is evaluated using triaxial tests. MICP treated sands with cementation levels ranging from young, uncemented sand to a highly cemented sandstonelike condition are subjected to undrained shear. A transition from strain hardening to strain softening behavior and a corresponding transition of global to localized failure as cementation is increased is observed. Moderately cemented specimens are subjected to various stress paths, which result in a change to the shear strength and volumetric behavior. Shear wave velocity is used to nondestructively monitor the change in small-strain stiffness during shearing, which provides an indication of cementation degradation as a function of strain level. Because shear wave velocity is influenced by both the level of cementation and the change in effective mean stress during shearing, the normalized shear modulus is used to evaluate the degradation of cementation during shearing. DA - 2015/6// PY - 2015/6// DO - 10.1061/(asce)gt.1943-5606.0001302 VL - 141 IS - 6 SP - SN - 1943-5606 KW - Cemented sand KW - Shear strength KW - Shear wave velocity KW - Microbial induced calcite precipitation KW - Sporosarcina pasteurii KW - Urea hydrolysis ER - TY - CONF TI - Social network analysis for construction specialty trade interference and work plan reliability AU - Abbasian-Hosseini, S. A. AU - Liu, M. AU - Hsiang, S. C2 - 2015/// C3 - International Group for Lean Construction DA - 2015/// SP - 143-152 ER - TY - JOUR TI - Reconstructed streamflow using SST and tree-ring chronologies over the southeastern United States AU - Patskoski, Jason AU - Sankarasubramanian, A. AU - Wang, Hui T2 - JOURNAL OF HYDROLOGY AB - A hybrid approach that considers both tree-ring chronologies and sea surface temperature (SST) data for reconstructing annual streamflow is proposed. The most common approach to reconstruct annual streamflow is to develop statistical regression relationships between principal components of tree rings and observed annual flow values and then extend the relationship to estimate annual streamflow values over the period for which tree-ring chronology is available. The primary limitation of this approach is in estimating high flow values since tree-ring growth reaches its potential limit during wet years. The proposed hybrid approach overcomes this limitation by using SST conditions from the tropical Pacific and tree-ring chronologies from the watershed for reconstructing annual streamflows. For this purpose, we considered eight virgin watersheds having long tree-ring chronologies over the southeastern United States. Given the role of El Nino Southern Oscillation (ENSO) in influencing the hydroclimatology of the southeastern United States, we estimated the periodic component of streamflow using Nino3.4 – an index representing ENSO – and the non-periodic component of streamflow using the non-periodic component of tree rings that represent interannual variability of moisture supply within the region. We employed Singular Spectrum Analysis (SSA) for extracting periodic and non-periodic components from tree-ring chronologies, Nino3.4 and streamflow data. The proposed tree ring and SST hybrid approach was compared with the traditional principal component regression (PCR) approach based on cross-validation. Results show that inclusion of SST provided better reconstructed flow values during high flow years but also resulted in overestimation of flow during low flow years. Combination of annual streamflow estimates from the two models – PCR and the hybrid approach – resulted in improved estimates of reconstructed annual streamflow for the selected eight watersheds. Potential applications for such improved reconstructed streamflow estimates is also discussed. DA - 2015/8// PY - 2015/8// DO - 10.1016/j.jhydrol.2015.05.041 VL - 527 SP - 761-775 SN - 1879-2707 KW - Dendro-hydrology KW - Streamflow reconstruction KW - Singular spectrum analysis KW - Principal component analysis KW - Paleo-climate ER - TY - JOUR TI - Real-Time Guidance for Hydrant Flushing Using Sensor-Hydrant Decision Trees AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - A utility may detect contaminant in a water distribution network through water quality sensor information, which indicates that a biological pathogen or chemical contaminant is present in the network. A utility manager should identify actions that can be taken to protect public health, and flushing a contaminant by opening a set of hydrants can be an effective response action. Hydrants should be selected and timed to flush the contaminant; however, accurately ascertaining the characteristics of the contaminant source may be impossible, which creates difficulties in developing a hydrant flushing strategy. This research develops a decision-making approach that is designed to select hydrant flushing strategies in response to sensor activations and does not require information about the characteristics of the contaminant source. A sensor-hydrant decision tree is introduced to provide a library of rules for opening and closing hydrants based on the order of activated sensors. Sensor-hydrant decision trees are developed for a wide range of contaminant events using a simulation-optimization methodology. Potential contamination events are generated using Monte Carlo simulation and are simulated using a water distribution system model. Events are classified based on the order of the activation of water quality sensors in the network, and a noisy genetic algorithm is used to identify hydrant strategies for each class of events. Three sensor-hydrant decision trees are developed to represent risky, risk-averse, and adaptive management strategies. A risk-averse strategy specifies immediate actions to achieve average performance over many events. A risky strategy specifies specialized actions based on the prediction of the plume movement or a decision to wait to receive more information. An adaptive strategy specifies the actions for opening hydrants as each sensor is activated. An adaptive approach does not require predictions of the plume movement, but may result in lower performance due to delays in taking actions. The methodology is demonstrated to develop sensor-hydrant decision trees for a virtual midsized municipality, Mesopolis. DA - 2015/6// PY - 2015/6// DO - 10.1061/(asce)wr.1943-5452.0000475 VL - 141 IS - 6 SP - SN - 1943-5452 KW - Hydrant flushing KW - Decision tree KW - Noisy genetic algorithm KW - Water distribution contamination event mitigation KW - Threat management KW - Adaptive management KW - Evolutionary computation adaptive strategies ER - TY - JOUR TI - Physical and Biological Release of Poly- and Perfluoroalkyl Substances (PFASs) from Municipal Solid Waste in Anaerobic Model Landfill Reactors AU - Allred, B. McKay AU - Lang, Johnsie R. AU - Barlaz, Morton A. AU - Field, Jennifer A. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - A wide variety of consumer products that are treated with poly- and perfluoroalkyl substances (PFASs) and related formulations are disposed of in landfills. Landfill leachate has significant concentrations of PFASs and acts as secondary point sources to surface water. This study models how PFASs enter leachate using four laboratory-scale anaerobic bioreactors filled with municipal solid waste (MSW) and operated over 273 days. Duplicate reactors were monitored under live and abiotic conditions to evaluate influences attributable to biological activity. The biologically active reactors simulated the methanogenic conditions that develop in all landfills, producing ∼140 mL CH4/dry g refuse. The average total PFAS leaching measured in live reactors (16.7 nmol/kg dry refuse) was greater than the average for abiotic reactors (2.83 nmol/kg dry refuse), indicating biological processes were primarily responsible for leaching. The low-level leaching in the abiotic reactors was primarily due to PFCAs ≤C8 (2.48 nmol/kg dry refuse). Concentrations of known biodegradation intermediates, including methylperfluorobutane sulfonamide acetic acid and the n:2 and n:3 fluorotelomer carboxylates, increased steadily after the onset of methanogenesis, with the 5:3 fluorotelomer carboxylate becoming the single most concentrated PFAS observed in live reactors (9.53 nmol/kg dry refuse). DA - 2015/7/7/ PY - 2015/7/7/ DO - 10.1021/acs.est.5b01040 VL - 49 IS - 13 SP - 7648-7656 SN - 1520-5851 ER - TY - JOUR TI - Modified Layered-Sectional Analysis for Forensic Investigation AU - McCoy, Brad C. AU - Seracino, Rudolf AU - Leming, Michael L. T2 - JOURNAL OF PERFORMANCE OF CONSTRUCTED FACILITIES AB - This paper describes a modification to the layered-sectional analysis approach, which provides the engineer with a tool to assess structural behavior of concrete beams with localized damage, a problem not well suited to classical, closed-form solutions. The modified layered-sectional analysis (MLSA) framework is applied to a forensic investigation case study in which two prestressed double-tee beams are exposed to a short duration, intense fire in a parking structure. The results of the MLSA are within 1% of the case study load test, which indicates that the MLSA could be a useful, computationally efficient tool for the investigating engineer to predict the postfire serviceability and strength of damaged beams, and potentially eliminate the need for expensive load testing. A short parametric study is included for the research engineer interested in the MLSA for predicting the postdamage behavior of non-standard materials such as enhanced sustainability concrete (ESC). DA - 2015/8// PY - 2015/8// DO - 10.1061/(asce)cf.1943-5509.0000583 VL - 29 IS - 4 SP - SN - 1943-5509 KW - Layered-sectional analysis KW - Sustainability KW - Damage assessment KW - Dynamic elastic (Young's) modulus KW - Resonant frequency ER - TY - JOUR TI - Low-Cycle Fatigue and Ratcheting Responses of Elbow Piping Components AU - Hassan, T. AU - Rahman, M. AU - Bari, S. T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - The objective of this study was to investigate low-cycle fatigue and ratcheting responses of elbows through experimental and analytical studies. Low-cycle fatigue and ratcheting damage accumulation in piping components may occur under repeated reversals of loading induced by earthquake and/or thermomechanical operation. Ratcheting and fatigue damage accumulation can cause failure of piping systems through fatigue cracks or plastic buckling. However, the ratcheting damage induced failures are yet to be understood clearly; consequently, ASME Code design provisions against ratcheting failure continue to be a controversial issue over the last two decades. A systematic set of piping component experimental responses involving ratcheting and a computational tool to simulate these responses will be essential to rationally address the issue. Development of a constitutive model for simulating component ratcheting responses remains to be a challenging problem. In order to develop an experimentally validated constitutive model, a set of elbow experiments was conducted. The loading prescribed in the experiments involved displacement-controlled or force-controlled in-plane cyclic bending with or without internal pressure. Force, displacement, internal pressure, elbow diameter change, and strains at four locations of the elbow specimens were recorded. This article presents and discusses the results from the experimental study. A sister article evaluates seven different constitutive models against simulating these elbow ratcheting and fatigue responses. DA - 2015/6// PY - 2015/6// DO - 10.1115/1.4029068 VL - 137 IS - 3 SP - SN - 1528-8978 ER - TY - JOUR TI - Impacts of Near-Term Climate Change and Population Growth on Within-Year Reservoir Systems AU - Singh, Harminder AU - Sinha, Tushar AU - Sankarasubramanian, A. T2 - Journal of Water Resources Planning and Management AB - Climate change and increased urban demand can significantly stress water supply systems, emphasizing the importance of reallocating reservoir storage for the designed uses. Most studies on climate change assessment have analyzed arid region reservoirs due to high interannual variability in streamflows. This study focuses on a within-year reservoir system, Lake Jordan in North Carolina, from a temperate region that has been experiencing rapid growth since the 1990s. Given the interest in utilizing climate change projections for planning purposes, the current operational policies are evaluated, and revised rules for operating the within-year system over 30 year period (2012–2041) are suggested. Downscaled general circulation model (GCM) projections are used to implement the soil and water assessment tool (SWAT) model for the Upper Cape Fear River basin to estimate changes in mean monthly streamflows during 2012–2041 at Lake Jordan. Projected monthly streamflows from four GCMs indicate wet winter conditions and increased interannual variability. The authors forced the reservoir model with multiple streamflow realizations that preserve the projected changes in monthly streamflow using a stochastic scheme. The within-year reservoir system performance was evaluated under stationary climate, climate change under existing and projected water demands, and by investigating interventions to ensure the design reliability under increased demands. These results indicate that the changes in the reliability due to increased urban demands are small because initial reservoir storage ensure the demand for multiple seasons. However, increases in the urban demand and streamflow variability tend to decrease the reservoir resiliency, forcing the within-year reservoir to behave like an over-year system. This could result in increased period of proactive measures such as restrictions and necessitates periodical reevaluation of drought management plans for better managing existing systems. DA - 2015/6// PY - 2015/6// DO - 10.1061/(ASCE)WR.1943-5452.0000474 VL - 141 IS - 6 SP - 04014078 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(ASCE)WR.1943-5452.0000474 DB - Crossref KW - Climate change KW - Hydroclimate KW - Reservoir analyses KW - Water supply KW - Flood control ER - TY - JOUR TI - Effect of Seismic Load History on Deformation Limit States for Longitudinal Bar Buckling in RC Circular Columns AU - Feng, Yuhao AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - Journal of Structural Engineering AB - This paper investigates the impact of seismic load history on longitudinal bar buckling in reinforced concrete (RC) bridge columns. Previous research has shown that reinforcing bars are prone to buckling upon reversal from tensile strain. To quantify this effect, a hybrid analysis method using both fiber and solid elements is developed and implemented to assess the impact of seismic load history on reinforcing bar buckling. Forty earthquake ground motions are utilized to conduct nonlinear time history analysis of bridge columns using a fiber-based model. The longitudinal bar strain history from the fiber-based model is then utilized as the input to the finite element model. A parametric study is conducted for the purpose of developing design equations that provide strain limits prior to the onset of bar buckling. Simple design approaches are proposed based on the design equations. DA - 2015/8// PY - 2015/8// DO - 10.1061/(asce)st.1943-541x.0001153 VL - 141 IS - 8 SP - 04014187 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001153 DB - Crossref KW - Reinforced concrete KW - Load history effect KW - Reinforcing bar buckling KW - Strain KW - Seismic effects ER - TY - JOUR TI - Constitutive Models in Simulating Low-Cycle Fatigue and Ratcheting Responses of Elbow AU - Hassan, T. AU - Rahman, M. T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - As stated in the sister article that the objective of this study was to explore the low-cycle fatigue and ratcheting failure responses of elbow components through experimental and analytical studies. Low-cycle fatigue and ratcheting damage accumulation in piping components may occur under load reversals induced by earthquakes or thermomechanical operations. Ratcheting damage accumulation can cause failure of components through cracking or plastic buckling. Hence, design by analysis of piping components against ratcheting failure will require simulation of this response with reasonable accuracy. In developing a constitutive model that can simulate ratcheting responses of piping components, a systematic set of elbow experiments involving deformation and strain ratcheting were conducted and reported in the sister article. This article will critically evaluate seven different constitutive models against their elbow response simulation capabilities. The widely used bilinear, multilinear, and Chaboche models in ansys are first evaluated. This is followed by evaluation of the modified Chaboche, Ohno–Wang, modified Ohno–Wang, and Abdel Karim–Ohno models. Results from this simulation study are presented to demonstrate that all the seven models can simulate the elbow force response reasonably. The bilinear and multilinear models can simulate the initial elbow diameter change or strain accumulation, but always simulate shakedown during the subsequent cycles when for some of the cases the experimental trends are ratcheting. Advanced constitutive models like Chaboche, modified Chaboche, Ohno–Wang, modified Ohno–Wang, and Abdel Karim–Ohno can simulate many of the elbow ratcheting responses well, but for some of the strain responses, these models simulate negative ratcheting, which is opposite to the experimental trend. Finally, implications of negative ratcheting simulation are discussed and suggestions are made for improving constitutive models ratcheting response simulation. DA - 2015/6// PY - 2015/6// DO - 10.1115/1.4029069 VL - 137 IS - 3 SP - SN - 1528-8978 ER - TY - CONF TI - A multi-agent auction-based approach for modeling of signalized intersections AU - Mashayekhi, M. AU - List, G. C2 - 2015/// C3 - Workshop on Synergies Between Multiagent Systems, Machine Learning and Complex Systems DA - 2015/// ER - TY - JOUR TI - Rutting performance evaluation of asphalt mix with different types of geosynthetics using MMLS3 AU - Lee, Jusang AU - Kim, Y. Richard AU - Lee, Jaejun T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - This paper presents an evaluation of the rutting performance of geosynthetics in asphalt pavements. The rutting performance of both a fibreglass geogrid and a sheet reinforcement material were evaluated using the third-scale model mobile loading simulator (MMLS3). The surface profile of each type of reinforced slab (and a control slab) was monitored and compared. To investigate movement of the mixtures caused by MMLS3 loading as well as the interfaces of the reinforcements in the asphalt slabs, trench cuts were made once the MMLS3 rutting tests were complete. The results demonstrated that reinforcement can reduce downward ruts and that different types of reinforcement exhibited different shear flow behaviour. The geogrid-reinforced slabs showed the shallowest ruts and the most shear flow resistance due to the tension resistance of the geogrid. They exhibited confinement and increased friction due to the aggregate particles that were locked in the geogrid openings. The sheet-reinforced slabs exhibited the highest shear flow humps due to the lack of interlocking and bonding strength at the rutting test temperature. In addition, the geogrid openings, which were supposed to provide interlocking and anchoring, in fact generated a relatively high volume of voids at the interface between lifts. Further research is needed to evaluate the effects of high air voids at the lift interface on pavement performance. DA - 2015/11/26/ PY - 2015/11/26/ DO - 10.1080/10298436.2014.972916 VL - 16 IS - 10 SP - 894-905 SN - 1477-268X KW - fibreglass sheet KW - geosynthetic KW - rutting KW - third-scale model mobile loading simulator KW - accelerated pavement testing KW - fibreglass geogrid ER - TY - JOUR TI - Primary causes of cracking of asphalt pavement in North Carolina: field study AU - Park, Hong Joon AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - Presently, North Carolina is experiencing higher than anticipated rates of fatigue cracking. Field materials and pavement conditions are investigated to find the primary causes of cracking in North Carolina. This study finds that pavements with high asphalt content tend to be in good condition based on the top-down cracking (TDC) observed in the top layer, and pavements with low air void contents tend also to be in good condition. In addition, fine-graded mixes tend to yield a better pavement condition than coarse-graded mixes. The structure-related comprehensive analysis suggests that debonding is one of the major causes of a poor pavement condition. Road widening is another cause of cracking that can develop into fatigue cracking. Regions in which bottom-up cracking is observed tend to have larger bending strains at the bottom of the asphalt layer than regions where TDC is observed. DA - 2015/9/14/ PY - 2015/9/14/ DO - 10.1080/10298436.2014.943220 VL - 16 IS - 8 SP - 684-698 SN - 1477-268X KW - asphalt KW - bottom-up cracking KW - pavement KW - fatigue cracking KW - top-down cracking KW - road widening KW - debonding ER - TY - JOUR TI - Nonlinear viscoelastic analysis of asphalt cement and asphalt mastics AU - Underwood, B. Shane AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - The nonlinear viscoelastic (NLVE) behaviour of asphalt cement and asphalt mastic are studied using temperature and frequency sweep tests and repeated stress sweep cyclic load tests. These experiments show that the response functions of these materials are strain-level dependent. The experiments also show that NLVE occurs simultaneously with other mechanisms, which complicates isolation and subsequent characterisation. For the asphalt mastics studied, the NLVE is found to relate to only the influences of the asphalt cement. Based on these experiments and analyses, a thermodynamics-based constitutive equation is proposed. The proposed model is chosen based on the hypothesis that the observed NLVE is strain related, which is different from other similar models and agrees with existing frameworks for evaluating damage. The resulting model is found to capably predict the stress–strain behaviour of asphalt cement and asphalt mastics at different volumetric concentrations of filler under cyclic and constant rate loading. DA - 2015/7/3/ PY - 2015/7/3/ DO - 10.1080/10298436.2014.943133 VL - 16 IS - 6 SP - 510-529 SN - 1477-268X KW - rheometrical testing KW - modelling KW - asphalt cement KW - nonlinear viscoelastic KW - asphalt mastic ER - TY - JOUR TI - Laboratory Evaluation of Warm-Mix Asphalt Mixtures for Moisture and Rutting Susceptibility AU - Malladi, Haritha AU - Ayyala, Dinesh AU - Tayebali, Akhtarhusein A. AU - Khosla, N. Paul T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - Since its introduction, warm mix asphalt (WMA) has garnered a lot of attention and interest from the pavement industry as a promising technology to replace the conventional hot mix asphalt (HMA). Despite its many benefits, including reducing emissions and fuel usage, definitive answers on the feasibility of replacing HMA pavements with WMA are yet to be answered. A major concern for WMA is susceptibility to moisture-induced damage. In this research study, mixtures prepared using three WMA technologies- viz. Sasobit, Advera WMA and the Foamer were evaluated for their moisture susceptibility and permanent deformation in comparison with an HMA mixture. Tensile strength ratio (TSR) and asphalt pavement analyzer (APA) tests were conducted on these mixtures. Results show that moisture-based WMA technologies (Advera and Foamer) are more susceptible to moisture damage. However, rut depths evaluated using APA, even for moisture-conditioned specimens, indicated WMA performance on par with that of HMA. Even though the TSR values do not meet specifications, APA test results indicate good potential for the widespread use of WMA. DA - 2015/5// PY - 2015/5// DO - 10.1061/(asce)mt.1943-5533.0001121 VL - 27 IS - 5 SP - SN - 1943-5533 KW - Warm mix asphalt KW - Tensile strength ratio (TSR) KW - Asphalt pavement analyzer (APA) KW - Moisture susceptibility KW - Rutting ER - TY - JOUR TI - Investigating landfill leachate as a source of trace organic pollutants AU - Clarke, Bradley O. AU - Anumol, Tarun AU - Barlaz, Morton AU - Snyder, Shane A. T2 - CHEMOSPHERE AB - Landfill leachate samples (n=11) were collected from five USA municipal solid waste (MSW) landfills and analyzed for ten trace organic pollutants that are commonly detected in surface and municipal wastewater effluents (viz., carbamazepine, DEET, fluoxetine, gemfibrozil, PFOA, PFOS, primidone, sucralose, sulfamethoxazole and trimethoprim). Carbamazepine, DEET, PFOA and primidone were detected in all leachate samples analyzed and gemfibrozil was detected in samples from four of the five-landfill sites. The contaminants found in the highest concentrations were DEET (6900-143000 ng L(-1)) and sucralose (<10-621000 ng L(-1)). Several compounds were not detected (fluoxetine) or detected infrequently (sulfamethoxazole, trimethoprim and PFOS). Using the average mass of DEET in leachate amongst the five landfills and scaling the mass release from the five test landfills to the USA population of landfills, an order of magnitude estimate is that over 10000 kg DEET yr(-1) may be released in leachate. Some pharmaceuticals have similar annual mean discharges to one another, with the estimated annual discharge of carbamazepine, gemfibrozil, primidone equating to 53, 151 and 128 kg year(-1). To the authors knowledge, this is the first time that primidone has been included in a landfill leachate study. While the estimates developed in this study are order of magnitude, the values do suggest the need for further research to better quantify the amount of chemicals sent to wastewater treatment facilities with landfill leachate, potential impacts on treatment processes and the significance of landfill leachate as a source of surface water contamination. DA - 2015/5// PY - 2015/5// DO - 10.1016/j.chemosphere.2015.02.030 VL - 127 SP - 269-275 SN - 1879-1298 KW - Landfill leachate KW - Contaminants of emerging concern KW - DEET KW - Sucralose KW - Primidone ER - TY - JOUR TI - Influence of Nonviscous Damping on Seismic Inelastic Displacements AU - Chai, Y. H. AU - Kowalsky, Mervyn J. T2 - INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS AB - Viscous damping, which assumes a resisting force proportional to the instantaneous velocity, results in energy dissipation that increases linearly with frequency. Such energy dissipation, however, is not strongly supported by experiments. The energy dissipative characteristics of damping can be improved by nonviscous hereditary model, where the damping force is treated as dependent on the response history. A weighting function with built-in exponential decay can be used to represent the fading memory of damping where the recent history is given a greater influence over its distant past. This paper investigates the seismic response of structures using exponentially decaying nonviscous damping and compares the response with that of classical viscous damping. Preliminary results show an increase in inelastic displacements in the exponential damping model for both normal and near-fault ground motions. As part of the study, system characteristics of the exponential damping model are investigated. DA - 2015/6// PY - 2015/6// DO - 10.1142/s0219455414500746 VL - 15 IS - 5 SP - SN - 1793-6764 KW - Exponential damping KW - seismic loading KW - inelastic displacement ER - TY - JOUR TI - Independent Data Validation of an in Vitro Method for the Prediction of the Relative Bioavailability of Arsenic in Contaminated Soils AU - Bradham, Karen D. AU - Nelson, Clay AU - Juhasz, Albert L. AU - Smith, Euan AU - Scheckel, Kirk AU - Obenour, Daniel R. AU - Miller, Bradley W. AU - Thomas, David J. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - In vitro bioaccessibility (IVBA) assays estimate arsenic (As) relative bioavailability (RBA) in contaminated soils to improve accuracy in human exposure assessments. Previous studies correlating soil As IVBA with RBA have been limited by the use of few soil types and sources of As, and the predictive value of As IVBA has not been validated using an independent set of As-contaminated soils. In this study, a robust linear model was developed to predict As RBA in mice using IVBA, and the predictive capability of the model was independently validated using a unique set of As-contaminated soils. Forty As-contaminated soils varying in soil type and contaminant source were included in this study, with 31 soils used for initial model development and nine soils used for independent model validation. The initial model reliably predicted As RBA values in the independent data set, with a mean As RBA prediction error of 5.4%. Following validation, 40 soils were used for final model development, resulting in a linear model with the equation RBA = 0.65 × IVBA + 7.8 and an R(2) of 0.81. The in vivo-in vitro correlation and independent data validation presented provide critical verification necessary for regulatory acceptance in human health risk assessment. DA - 2015/5/19/ PY - 2015/5/19/ DO - 10.1021/acs.est.5b00905 VL - 49 IS - 10 SP - 6312-6318 SN - 1520-5851 ER - TY - JOUR TI - Impact of D/t on seismic behavior of reinforced concrete filled steel tubes AU - Brown, N.K. AU - Kowalsky, M.J. AU - Nau, J.M. T2 - Journal of Constructional Steel Research AB - Reinforced concrete filled steel tubes (RCFSTs) are commonly used for bridge substructures in high seismic regions where the steel tube is used as a permanent casing which eases construction. Concrete confinement is provided by the steel tube, increasing the compressive strength and strain capacity. Tests were performed on twelve large scale RCFSTs, seven of the tests focused on varying D/t ratio and the remaining five focused on varying internal reinforcement. The tubes were subjected to reversed cyclic four-point bending with a constant moment region centered in the pile. The large scale specimens consisted of outer diameters of 20 to 24 in. (508 to 610 mm) and diameter-to-thickness ratios between 33 and 192. Strain limit states for the onset of tube wall local buckling and fracture are developed, as is an expression for equivalent viscous damping for direct displacement-based design. The impact of the tubes on confinement and analysis methods is also discussed. DA - 2015/4// PY - 2015/4// DO - 10.1016/j.jcsr.2015.01.013 VL - 107 SP - 111-123 J2 - Journal of Constructional Steel Research LA - en OP - SN - 0143-974X UR - http://dx.doi.org/10.1016/j.jcsr.2015.01.013 DB - Crossref KW - Reinforced Concrete Filled Steel Tube (RCFST) KW - Seismic KW - Bridge KW - Ductility KW - Buckling KW - Damping ER - TY - JOUR TI - Grouted shear stud connection for steel bridge substructures AU - Fulmer, S.J. AU - Kowalsky, M.J. AU - Nau, J.M. T2 - Journal of Constructional Steel Research AB - This paper discusses the seismic performance of composite connections designed to capacity protect critical welded regions of steel bridge pier connections. Past research has shown that directly welding hollow circular steel pipes to a steel cap beam, regardless of weld configuration, does not mitigate the undesirable failure mode of brittle cracking in the welded region. Hence, capacity protection of the welds becomes an attractive option. A new detail proposed in this paper consists of a composite connection intended to relocate the plastic hinge away from the weld interface. Through full scale quasi-static testing, nonlinear FEA, and scaled shake table testing the connection was shown to perform well. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.jcsr.2015.02.009 VL - 109 SP - 72-86 J2 - Journal of Constructional Steel Research LA - en OP - SN - 0143-974X UR - http://dx.doi.org/10.1016/j.jcsr.2015.02.009 DB - Crossref KW - Grouted connection KW - Steel columns KW - Seismic KW - Bridge KW - Ductility KW - Buckling ER - TY - JOUR TI - Finite-Element Method to Predict Reinforcing Bar Buckling in RC Structures AU - Feng, Yuhao AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - Journal of Structural Engineering AB - Buckling of longitudinal bars is a common form of damage in reinforced concrete (RC) structures subjected to earthquakes. Previous research has illustrated the impact of cyclic loading on bar buckling which often occurs upon the reversal from a tensile loading cycle. This paper presents a finite-element method to predict reinforcement buckling under seismic loading that also captures the details of the buckling mechanism. This method combines a fiber-based model to simulate the reinforced concrete member itself and an independent finite-element model of the local plastic hinge region. The strain demands in the plastic hinge region are determined from the fiber-based model of the overall structure subjected to the ground motion. The strain history is then imposed on the finite element bar buckling model to predict the localized behavior. Comparisons between the model performance and experimental observations are shown to assess the accuracy of the proposed method. DA - 2015/5// PY - 2015/5// DO - 10.1061/(asce)st.1943-541x.0001048 VL - 141 IS - 5 SP - 04014147 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001048 DB - Crossref KW - Concrete structures KW - Reinforced concrete KW - Load history KW - Buckling KW - Strain KW - Finite element method KW - Bars KW - Reinforced concrete KW - Load history effect KW - Reinforcing bar buckling KW - Strain KW - Analysis and computation ER - TY - JOUR TI - Degraded secant modulus for permanent deformation of soils AU - Ahn, Jaehun AU - Gabr, Mohammed AU - Oh, Jeongho AU - Shin, Hosung T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - Two constitutive models, one with five parameters and the other with three parameters, were proposed for use in the prediction of permanent deformation of geotechnical materials under repetitive loading. The proposed model can be used with numerical tools such as the finite element method with equivalent linear analysis. The degraded secant modulus model with five parameters may employ the parameters of the material models widely accepted in pavement engineering practice to analyse to more general soil problems. The model parameters of the three-parameter model can be estimated based on the results of cyclic triaxial tests or by conducting inverse analysis based on the results of large-scale plate load tests, which are addressed and exemplified in detail in this article. DA - 2015/7/3/ PY - 2015/7/3/ DO - 10.1080/10298436.2014.943208 VL - 16 IS - 6 SP - 549-558 SN - 1477-268X KW - subgrade KW - plate load test KW - unbound material KW - permanent deformation KW - numerical analysis ER - TY - JOUR TI - Assessment of remedial measures to reduce exceedance probability of performance limit states in embankment dams AU - Khalilzad, Mahdi AU - Gabr, Mohammed A. AU - Hynes, Mary Ellen T2 - Computers and Geotechnics AB - Results of a series of numerical analyses, simulating three remedial measures applied to an embankment dam, are used to investigate the extent of lessening the severity of the distress level under flood loading. Conceptually, the three remedial measures are increasing the mean effective stress, adding a low permeability curtain to limit seepage, and improving drainage to lower pore water pressure magnitudes at key locations. The results are presented in the context of exceeding predefined limit states in terms of toe deformation and hydraulic gradient. Constructing a downstream berm has a significant impact on the exceedance probabilities of the deformation limit states at the toe, but a small impact on the toe gradient values. Adding a low permeability curtain below the dam crest considerably reduces both deformation and gradient magnitudes in relation to the predefined limit states. This occurs due to an increased seepage path leading to a higher drop of pressure head and lower phreatic surface level; these two effects result in lower shear strains and less deformations at the toe. Improvement was observed by adding the toe drainage system with a hydraulic conductivity that is 4–20 times higher than the hydraulic conductivity of the embankment material. In this case, the exceedance probabilities of deformation limit states decrease and the impact is higher for a higher hydraulic conductivity of the drainage system compared to the embankment soil. Given the analyses configurations and parameters, constructing a berm at the toe leads to the lowest exceedance probabilities, in terms of deformation limit state, and thus seems to be the most effective approach among the three analyzed remedial measures. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.compgeo.2015.02.010 VL - 67 SP - 213-222 ER - TY - JOUR TI - An innovative seismic performance enhancement technique for steel building moment resisting connections AU - Morrison, Machel AU - Schweizer, Doug AU - Hassan, Tasnim T2 - JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH AB - This study develops and experimentally validates an innovative technique for enhancing the seismic performance of steel beam to column moment connections. The technique involves reducing the strength of specified regions of the beam flanges by exposing them to high temperatures followed by slow cooling. Analogous to the reduced beam section (RBS) connection, yielding and plastic hinge formation is promoted in the heat-treated beam section (HBS). Moreover, because the elastic and inelastic modulus of the steel is unmodified by the heat-treatment and the beam cross section is not altered, an HBS connection does not sacrifice elastic stiffness or buckling resistance as does the RBS. Design of the HBS connection was performed through detailed finite element analysis and material testing. Two large scale connections modified with the HBS technique were tested in this study. The test program showed that the proposed heat-treatment technique was successful in the promotion of yielding and plastic hinge development in the heat-treated regions with specimens attaining interstory drifts as high as 6% without weld or near weld fracture. Strength degradation due to beam buckling within the HBS was the observed failure mechanism in both specimens. Detail analyses of strain and beam deformation data are presented to explain the HBS connection plastic hinge formation and gradual strength degradation. Broader applications of the technique to other structural components are identified. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.jcsr.2015.02.010 VL - 109 SP - 34-46 SN - 1873-5983 KW - Steel moment connection KW - Seismic performance enhancement KW - Beam plastic hinge KW - Heat-treated beam section KW - Reduced beam section ER - TY - JOUR TI - Seismic fragility of threaded Tee-joint connections in piping systems AU - Ju, Bu Seog AU - Gupta, Abhinav T2 - INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING AB - This paper proposes a methodology to evaluate seismic fragility of threaded Tee-joint connections found in typical hospital piping systems. Existing experimental data on threaded Tee-joints of various sizes subjected to monotonic and cyclic loading indicates that the “First Leak” damage state is observed predominantly due to excessive flexural deformations at the Tee-joint section. The results of the monotonic and cyclic loading tests help us evaluate the characteristics for a given pipe size and material. A non-linear finite element model for the Tee-joint system is formulated and validated with the experimental results. It is shown that the Tee-joint section can be satisfactorily modeled using non-linear rotational springs. The system-level fragility of the complete piping system corresponding to the “First Leak” damage state is determined from multiple time-history analyses using a Monte-Carlo simulation accounting for uncertainties in demand. DA - 2015/// PY - 2015/// DO - 10.1016/j.ijpvp.2015.06.001 VL - 132 SP - 106-118 SN - 1879-3541 KW - Piping fragility KW - Piping limit-states KW - First-leakage piping fragility KW - Performance-based piping fragility ER - TY - JOUR TI - Investigation and evaluation of a novel technique on CFRT column connection AU - Yu, Yujie AU - Chen, Zhihua AU - Wang, Xiaodun T2 - JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH AB - This study investigated the effect of an innovative technique, heat treatment, on Q345B steel, which is generally used in China, and the application potential of this technique for H-beam moment connections to concrete filled rectangular steel tube (CFRT) column. A heat-treating process with ultra-high temperature heating and subsequent controlled slow cooling could have a weakening effect on steel strength. The effect of this heat-treating process on steel was investigated through a series of material tests on Q345B steel (Chinese standard). The Chaboche hysteresis material model was selected and calibrated to better describe the strength behavior under cyclic loading, and was then used for subsequent seismic simulations. This technique can be utilized to improve the seismic performance of connections by locally heat-treating the beam section (HBS), and then inducing the plastic hinge away from the critical region. The effect of HBS was investigated on two common CFRT column connections in China, namely, through-diaphragm and internal-diaphragm CFRT column connections. Results showed that the novel heat-treating process also had a significant weakening effect on Chinese Q345B steel. The hysteresis behavior of steel was different from the monotonic performance. The Chaboche model can effectively describe the hysteresis properties. The application of HBS succeeded in inducing plastic strain developed in the heat-treated region, and can reduce strain concentrations without significant connection moment strength loss. DA - 2015/10// PY - 2015/10// DO - 10.1016/j.jcsr.2015.06.014 VL - 113 SP - 195-208 SN - 1873-5983 KW - Heat treated beam section (HBS) KW - CFRT column connection KW - Chaboche model KW - Through-diaphragm KW - Internal-diaphragm ER - TY - JOUR TI - Improved schmidt method for predicting temperature development in mass concrete AU - Bobko, C. R. AU - Zadeh, V. Z. AU - Seracino, R. T2 - ACI Materials Journal DA - 2015/// PY - 2015/// VL - 112 IS - 4 SP - 579-586 ER - TY - JOUR TI - Evaluation of Copper Oxide Oxidation for Quantification of Lignin in Municipal Solid Waste AU - De la Cruz, Florentino Banaag AU - Dittmar, Thorsten AU - Niggemann, Jutta AU - Osburn, Christopher L. AU - Barlaz, Morton A. T2 - Environmental Engineering Science AB - The ability to quantify lignin is an important tool for characterizing the extent of decomposition of municipal solid waste (MSW). Traditionally, acid insoluble Klason lignin (KL) has been used to measure lignin. However, synthetic organic materials such as plastics and rubber present in MSW interfere with the traditional KL method, resulting in artificially high measurements. Another method for lignin analysis is CuO oxidation, in which lignin is oxidatively hydrolyzed into phenolic monomers that are quantified by high-performance liquid chromatography or gas chromatography–mass spectrography. The objective of this study was to evaluate the applicability of CuO oxidation to measure the lignin content of MSW. The study demonstrated that analysis of lignin monomers can be simplified by skipping the ethyl acetate extraction step and that ball milling is not necessary to optimize CuO oxidation. Neither the MSW components (e.g., plastics and metals) nor extractives affected CuO oxidation. The ratio of cellulose (Cel) plus hemicellulose (H) to KL [(Cel+H)/KL] has traditionally been used as an indicator of the extent of MSW decomposition. The use of Cel plus H to the sum of CuO oxidation products of lignin (Λ8) [(Cel+H)/Λ8] exhibited a similar trend to the traditional metric. CuO analysis provided information on the presence of hardwood, softwood, and nonwoody material in buried MSW, but is not recommended as a substitute for KL analysis. DA - 2015/6// PY - 2015/6// DO - 10.1089/ees.2014.0402 VL - 32 IS - 6 SP - 486-496 J2 - Environmental Engineering Science LA - en OP - SN - 1092-8758 1557-9018 UR - http://dx.doi.org/10.1089/ees.2014.0402 DB - Crossref KW - municipal solid waste KW - CuO oxidation KW - lignin ER - TY - JOUR TI - A new way for incorporating GCM information into water shortage projections AU - Seo, S. B. AU - Kim, Y. O. AU - Kim, C. R. T2 - Water DA - 2015/// PY - 2015/// VL - 7 IS - 5 SP - 2435-2450 ER - TY - JOUR TI - Probabilistic risk assessment: Piping fragility due to earthquake fault mechanisms AU - Ju, B. S. AU - Jung, W. AU - Noh, M. H. T2 - Mathematical Problems in Engineering DA - 2015/// PY - 2015/// ER - TY - JOUR TI - New predictive models for the dynamic modulus of hot mix asphalt AU - Sakhaeifar, Maryam S. AU - Kim, Y. Richard AU - Kabir, Pooyan T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper presents a fundamental modeling framework for prediction of dynamic modulus of hot mix asphalt mixtures based on viscoelastic principles. The outcomes are two closed-form models that can be used to predict the mixture dynamic modulus for a wide range of temperatures (−10°, 4.4°, 37.8°, and 54.4 °C) recommended in the American Association of State Highway and Transportation Officials (AASHTO) TP62-03 test protocol. To develop and verify the models a large database that covers the complete range of potential input conditions was assembled. In general, the proposed models predict the dynamic modulus with a very good level of accuracy. DA - 2015/2/1/ PY - 2015/2/1/ DO - 10.1016/j.conbuildmat.2014.11.011 VL - 76 SP - 221-231 SN - 1879-0526 KW - Hot mix asphalt concrete KW - Dynamic modulus KW - Binder shear modulus KW - Time-temperature superposition KW - Mastercurve KW - Predictive model KW - Mechanistic-Empirical Pavement Design KW - Guide (MEPDG) ER - TY - JOUR TI - Multiple Baseline Testing: Experimental Method for Drawing Causal Inferences in Construction Engineering and Management Research AU - Albert, Alex AU - Hallowell, Matthew R. AU - Lingard, Helen AU - Kleiner, Brian M. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Identifying and evaluating solutions for critical industry challenges is a major theme of construction engineering and management (CEM) research. Researchers and practitioners in the construction sector often seek to invent, test, implement, and disseminate practical interventions that improve safety, productivity, quality, and other project success factors. Robust scientific research design is imperative for drawing valid causal inferences when testing the impact of new interventions. Unfortunately, the transient and dynamic nature of construction obfuscates the isolation of variables, thus making true experiments impractical or unethical. With roots in pharmaceutical research, multiple baseline testing (MBT), commonly known as multiple baseline design, is a promising and viable experimental technique that provides reinforced evidence for drawing causal inferences and analyzing change. The requisite process of replication through concurrent longitudinal studies, phased implementation, and inter- and intra-experimental unit comparisons allow researchers to isolate the impact of an intervention within constantly changing environments. This paper describes a protocol for the rigorous and valid implementation of MBT on construction projects based on the authors’ collective experience with the method. This paper describes how the proper use of MBT minimizes threats to internal validity and ensures the ethical treatment of research participants in subject-based research. The paper concludes by reviewing the common challenges associated with the adoption of MBT in construction research. It is expected that the discussions will equip researchers with the tools to conduct rigorous, robust, and reliable intervention studies with improved evidence for causality. DA - 2015/7// PY - 2015/7// DO - 10.1061/(asce)co.1943-7862.0000983 VL - 141 IS - 7 SP - SN - 1943-7862 KW - Multiple baseline testing KW - Multiple baseline design KW - Experimental research KW - Intervention studies KW - Research methods KW - Measuring change KW - Evaluating strategies KW - Quantitative methods ER - TY - JOUR TI - Mathematical Approach in Rheological Characterizing of Asphalt Emulsion Residues AU - Cho, Seong Hwan AU - Im, Jeong Hyuk T2 - MATHEMATICAL PROBLEMS IN ENGINEERING AB - Three different emulsion residues, such as SS1HP, HFE90, and SS-1VH (trackless), and a base asphalt binder (PG 64-22) are compared to characterize rheological properties by using DSR test. In order to capture the emulsion properties, different frequencies (from 1 to 100 rad/sec at a 10% constant shear rate) and temperatures (from −45°C to 75°C with 15°C increments) were applied. Then, a master curve for shear modulus was plotted for each emulsion. The transition of the HFE90 emulsion from viscous to elastic behavior occurs at lower temperatures, compared to the other materials. This emulsion is known for performing in a wider temperature range as shown in the results. The trackless emulsion presents an elastic behavior at intermediate temperatures. This product is known as having very fast setting and high resistance to shear stresses. The trackless emulsion presents the highest viscous and elastic modulus, followed by the PG 64-22 binder, SS1HP, and HFE90 emulsion. Shear strength test results show a behavior between trackless emulsion and SS1HP similar to the frequency sweep test results performed by DSR. DA - 2015/// PY - 2015/// DO - 10.1155/2015/797808 VL - 2015 SP - SN - 1563-5147 ER - TY - JOUR TI - Integrating a simplified emission estimation model and mesoscopic dynamic traffic simulator to efficiently evaluate emission impacts of traffic management strategies AU - Zhou, Xuesong AU - Tanvir, Shams AU - Lei, Hao AU - Taylor, Jeffrey AU - Liu, Bin AU - Rouphail, Nagui M. AU - Frey, H. Christopher T2 - TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT AB - This paper presents a computationally efficient and theoretically rigorous dynamic traffic assignment (DTA) model and its solution algorithm for a number of emerging emissions and fuel consumption related applications that require both effective microscopic and macroscopic traffic stream representations. The proposed model embeds a consistent cross-resolution traffic state representation based on Newell’s simplified kinematic wave and linear car following models. Tightly coupled with a computationally efficient emission estimation package MOVES Lite, a mesoscopic simulation-based dynamic network loading framework DTALite is adapted to evaluate traffic dynamics and vehicle emission/fuel consumption impact of different traffic management strategies. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.trd.2015.04.013 VL - 37 SP - 123-136 SN - 1361-9209 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84941658996&partnerID=MN8TOARS KW - Emission estimation KW - Dynamic traffic assignment KW - Integrated traffic emission model KW - Cross-resolution model ER - TY - JOUR TI - Identification of emission hotspots in roundabouts corridors AU - Fernandes, P. AU - Salamati, K. AU - Rouphail, N. M. AU - Coelho, M. C. T2 - TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT AB - Abstract This study describes a methodology to quantify and characterize the vehicular emissions of functionally interdependent roundabouts at a corridor level. Corridor segments include those upstream of each roundabout, the circulating area, downstream of the roundabout as well as midblock sub-segments between adjacent roundabouts. The main purpose of the study is to identify the locations along the corridors where emissions tend to be consistently high. These locations are termed “Emission Hotspots”. The methodology is applied to four existing roundabout corridors in San Diego (California) and Avon (Colorado) in the United States, and in Mealhada and Chaves (Portugal). An extensive sample of second-by-second speed traces is available for these four corridors with roundabouts. The analysis shows that when roundabouts are fairly spaced and have similar geometric design features, no significant differences are observed between emissions of roundabouts located in the corridor. In such cases, the downstream sub-segments are the emission hotspots both in absolute terms (overall contribution on total emissions is higher than 34%) and per unit distance (22% higher than the average corridor value). When roundabouts are unequally spaced the highest emissions hotspots (more than 9% above the average corridor value) are found at the circulating area sub-segments. The results also demonstrate that the entry deflection angle has a slight impact on the spatial distribution of emissions especially in the case of closely spaced roundabouts. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.trd.2015.04.026 VL - 37 SP - 48-64 SN - 1361-9209 KW - Roundabout corridor KW - Emissions KW - Vehicle Specific Power KW - Microscale analysis ER - TY - JOUR TI - EVALUATING THE ECO-GEOMORPHOLOGICAL CONDITION OF RESTORED STREAMS USING VISUAL ASSESSMENT AND MACROINVERTEBRATE METRICS AU - Doll, Barbara A. AU - Jennings, Gregory D. AU - Spooner, Jean AU - Penrose, David L. AU - Usset, Joseph L. T2 - JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION AB - Abstract The Stream Performance Assessment ( SPA ), a new rapid assessment method, was applied to 93 restored, 21 impaired, 29 reference, and 13 reference streams with some incision throughout North Carolina. Principal component analysis ( PCA ) indicated restored streams align more closely with reference streams rather than impaired streams. Further, PCA ‐based factor analysis revealed restored streams were similar to reference streams in terms of morphologic condition, but exhibited a greater range of scores relative to aquatic habitat and bedform. Macroinvertebrate sampling and GIS watershed analyses were conducted on 84 restored streams. SPA and watershed data were compared to Ephemeroptera, Plecoptera, and Trichoptera ( EPT ) taxa to determine which factors indicate stream health. SPA and watershed factors were used in least squares, ridge, and principal component regression ( PCR ) to develop a prediction model for EPT taxa. All three methods produced reasonable predictions for EPT taxa. Cross‐validation indicated ridge regression resulted in the lowest prediction error. The ridge model was then used to predict EPT taxa numbers for 21 impaired and 25 reference streams in addition to the 84 restored streams. Statistical comparisons of the predicted scores indicated urban streams (>10% impervious watershed cover) have lower expected numbers of EPT taxa. Rural restored streams have macroinvertebrate metric scores similar to those predicted for rural reference streams. DA - 2015/2// PY - 2015/2// DO - 10.1111/jawr.12233 VL - 51 IS - 1 SP - 68-83 SN - 1752-1688 UR - http://dx.doi.org/10.1111/jawr.12233 KW - rivers KW - streams KW - restoration KW - macroinvertebrates KW - watershed KW - stream assessment ER - TY - JOUR TI - Determining Aerosol Volatility Parameters Using a "Dual Thermodenuder" System: Application to Laboratory-Generated Organic Aerosols AU - Saha, Provat K. AU - Khlystov, Andrey AU - Grieshop, Andrew P. T2 - AEROSOL SCIENCE AND TECHNOLOGY AB - Thermodenuders (TD) are a tool widely used for measuring aerosol volatility in the laboratory and field. Extracting the parameters that dictate organic aerosol volatility from TD data is challenging because gas-particle partitioning rarely reaches equilibrium inside a TD operating under atmospheric conditions, thus a wide variety of parameter sets can explain observed evaporation. Component volatilities (as represented by saturation vapor pressure, Csat), cannot be directly extracted due to uncertainties in potential limitations to mass transfer (represented by mass accommodation coefficient, α) and components’ enthalpies of evaporation (ΔHvap). To address these limitations, we have developed a “dual TD” experimental approach in which one line uses a temperature-stepping TD (TS-TD) with a relatively long residence time (RT) and the other operates isothermally at variable residence time (VRT-TD). Data from this approach are used in tandem with an optimizing evaporation kinetics model to extract the values of parameters dictating volatility (Csat, and associated values of ΔHvap and α). The system was evaluated using laboratory generated dicarboxylic acid aerosols (adipic acid and succinic acid). Excellent agreement with previously published evaporation data collected with other TD systems was observed. Parameter values reported in the literature for the tested acids vary widely, but our results are generally consistent with those from studies that allow for nonunity values of α. For example, our results suggest that α for these aerosols are of order 0.1, in agreement with results determined by Saleh et al. (2009, 2012). Modeling results suggest that the addition of VRT-TD data provides tighter constraint on feasible ΔHvap and α values. The dual TD approach presented here does not rely on equilibration in the TD and thus can be directly applied to extract volatility parameters for more complex laboratory and ambient organic aerosol systems.Copyright 2015 American Association for Aerosol Research DA - 2015/8/3/ PY - 2015/8/3/ DO - 10.1080/02786826.2015.1056769 VL - 49 IS - 8 SP - 620-632 SN - 1521-7388 ER - TY - JOUR TI - A methodological framework for linking bioreactor function to microbial communities and environmental conditions AU - de los Reyes, Francis L, III AU - Weaver, Joseph E AU - Wang, Ling T2 - Current Opinion in Biotechnology AB - In the continuing quest to relate microbial communities in bioreactors to function and environmental and operational conditions, engineers and biotechnologists have adopted the latest molecular and 'omic methods. Despite the large amounts of data generated, gaining mechanistic insights and using the data for predictive and practical purposes is still a huge challenge. We present a methodological framework that can guide experimental design, and discuss specific issues that can affect how researchers generate and use data to elucidate the relationships. We also identify, in general terms, bioreactor research opportunities that appear promising. DA - 2015/6// PY - 2015/6// DO - 10.1016/j.copbio.2015.02.002 VL - 33 SP - 112-118 J2 - Current Opinion in Biotechnology LA - en OP - SN - 0958-1669 UR - http://dx.doi.org/10.1016/j.copbio.2015.02.002 DB - Crossref ER - TY - JOUR TI - Real time traffic flow outlier detection using short-term traffic conditional variance prediction AU - Guo, Jianhua AU - Huang, Wei AU - Williams, Billy M. T2 - TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES AB - Outliers in traffic flow series represent uncommon events occurring in the roadway systems and outlier detection and investigation will help to unravel the mechanism of such events. However, studies on outlier detection and investigations are fairly limited in transportation field where a vast volume of traffic condition data has been collected from traffic monitoring devices installed in many roadway systems. Based on an online algorithm that has the ability of jointly predict the level and the conditional variance of the traffic flow series, a real time outlier detection method is proposed and implemented. Using real world data collected from four regions in both the United States and the United Kingdom, it was found that outliers can be detected using the proposed detection strategy. In addition, through a comparative experimental study, it was shown that the information contained in the outliers should be assimilated into the forecasting system to enhance its ability of adapting to the changing patterns of the traffic flow series. Moreover, the investigation into the effects of outliers on the forecasting system structure showed a significant connection between the outliers and the forecasting system parameters changes. General conclusions are provided concerning the analyses with future work recommended to investigate the underlying outlier generating mechanism and outlier treatment strategy in transportation applications. DA - 2015/1// PY - 2015/1// DO - 10.1016/j.trc.2014.07.005 VL - 50 SP - 160-172 SN - 0968-090X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85027920814&partnerID=MN8TOARS KW - Outlier detection KW - Intervention analysis KW - Traffic flow series KW - Short term traffic forecasting KW - SARIMA plus GARCH KW - Kalman filter ER - TY - JOUR TI - Isogeometric collocation for phase-field fracture models AU - Schillinger, Dominik AU - Borden, Michael J. AU - Stolarski, Henryk K. T2 - COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING AB - Phase-field models based on the variational formulation for brittle fracture have recently been shown capable of accurately and robustly predicting complex crack behavior. Their numerical implementation requires costly operations at the quadrature point level, which may include finding eigenvalues and forming tensor projection operators. We explore the application of isogeometric collocation methods for the discretization of second-order and fourth-order phase-field fracture models. We show that a switch from isogeometric Galerkin to isogeometric collocation methods has the potential to significantly speed up phase-field fracture computations due to a reduction of point evaluations. We advocate a hybrid collocation–Galerkin formulation that provides a consistent way of weakly enforcing Neumann boundary conditions and multi-patch interface constraints, is able to handle the multiple boundary integral terms that arise from the weighted residual formulation, and offers the flexibility to adaptively improve the crack resolution in the fracture zone. We present numerical examples in one and two dimensions that illustrate the advantages of our approach. DA - 2015/2/1/ PY - 2015/2/1/ DO - 10.1016/j.cma.2014.09.032 VL - 284 SP - 583-610 SN - 1879-2138 KW - Phase-field modeling KW - Fracture KW - Isogeometric collocation ER - TY - JOUR TI - Full- and pilot-scale GAC adsorption of organic micropollutants AU - Kennedy, Anthony M. AU - Reinert, Allison M. AU - Knappe, Detlef R. U. AU - Ferrer, Imma AU - Summers, R. Scott T2 - WATER RESEARCH AB - Granular activated carbon (GAC) adsorption of 30 environmentally relevant micropollutants (MP) from four surface waters was investigated at the pilot-scale with empty bed contact times (EBCTs) of 7 and 15 min. An increase in background dissolved organic matter resulted in more and earlier MP breakthrough. Compared to an EBCT of 7 min, MP breakthrough at an EBCT of 15 min demonstrated 52% later breakthrough on average for five MPs on a throughput basis. A regression model was developed with data from three waters to predict MP throughput in bed volumes to 10% breakthrough (BV10%) based on the influent dissolved organic carbon concentration and the MP pH-dependent octanol-water partition coefficient, polarizability, and molecular volume. The regression model over predicted full-scale BV10% values when applied to a wastewater-water impacted water source and to GAC with a larger particle diameter, for which a particle size adjustment was able to account for most of the difference. DA - 2015/1/1/ PY - 2015/1/1/ DO - 10.1016/j.watres.2014.10.010 VL - 68 SP - 238-248 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84908518266&partnerID=MN8TOARS KW - Granular activated carbon KW - Trace organic contaminants KW - Drinking water treatment KW - Pesticides KW - Pharmaceuticals KW - Personal care products ER - TY - JOUR TI - An exact reanalysis technique for storm surge and tides in a geographic region of interest AU - Baugh, John AU - Altuntas, Alper AU - Dyer, Tristan AU - Simon, Jason T2 - COASTAL ENGINEERING AB - Understanding the effects of storm surge in hurricane-prone regions is necessary for protecting public and lifeline services and improving resilience. While coastal ocean hydrodynamic models like ADCIRC may be used to assess the extent of inundation, the computational cost may be prohibitive since many local changes corresponding to design and failure scenarios would ideally be considered. We present an exact reanalysis technique and corresponding implementation that enable the assessment of local subdomain changes with less computational effort than would be required by a complete resimulation of the full domain. So long as the subdomain is large enough to fully contain the altered hydrodynamics, changes may be made and simulations performed within it without the need to calculate new boundary values. Accurate results are obtained even when subdomain boundary conditions are forced only intermittently, and convergence is demonstrated by progressively increasing the frequency at which they are applied. Descriptions of the overall methodology, performance results, and accuracy, as well as case studies, are presented. DA - 2015/3// PY - 2015/3// DO - 10.1016/j.coastaleng.2014.12.003 VL - 97 SP - 60-77 SN - 1872-7379 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85027939365&partnerID=MN8TOARS KW - Hurricane KW - Storm surge KW - Subdomain modeling KW - ADCIRC ER - TY - JOUR TI - A framework for incorporating ecological releases in single reservoir operation AU - Wang, Hui AU - Brill, Earl D. AU - Ranjithan, Ranji S. AU - Sankarasubramanian, A. T2 - Advances in Water Resources AB - Most reservoir operation practices consider downstream environmental flow as a constraint to meet a minimum release. The resulting flow regime may not necessarily provide downstream aquatic conditions to support healthy ecosystems. These effects can be quantified in terms of changes in values of parameters that represent the flow regimes. Numerous studies have focused on determining the ecological response to hydrological alteration caused by reservoir operation. To mitigate hydrological alteration and restore the natural flow regime as much as possible, a reservoir operation framework is proposed to explicitly incorporate ecological flow requirements. A general optimization-based decision model is presented to consider simultaneously the multiple anthropogenic uses of the reservoir and desirable ecological releases represented by parameters that capture the flow regime. Multiple uses of the reservoir, including water supply, hydropower generation, etc., are modeled as a mixed integer programming problem. Hydropower generation, which is represented by a nonlinear function that usually depends on head and water flow, is linearized using a two-dimensional function. Investigations using a reservoir in Virginia, located in the southeastern United States, demonstrate that compared to standard releases based on current operation practice, releases simulated using this framework perform better in mimicking pre-development flows. The tradeoff between anthropogenic use and ecological releases is investigated. The framework is first demonstrated for instances with perfect stream flow information. To examine the flexibility of this framework in reservoir release management, monthly flow forecasts and disaggregated daily flow conditions are incorporated. Retrospective monthly flow forecasts are obtained through regression models that use gridded precipitation forecasts and gridded soil moisture estimates as predictors. A nonparametric method is chosen to disaggregate monthly flow forecasts to daily flow conditions. Compared with daily flow climatology, forecasted monthly and daily flow better preserves flow variability and result in lower changes of flow parameters under the proposed framework. DA - 2015/4// PY - 2015/4// DO - 10.1016/j.advwatres.2015.01.006 VL - 78 SP - 9-21 J2 - Advances in Water Resources LA - en OP - SN - 0309-1708 UR - http://dx.doi.org/10.1016/j.advwatres.2015.01.006 DB - Crossref KW - Ecological flow requirements KW - Natural flow regime KW - Sustainable reservoir operation KW - Mixed integer linear programming ER - TY - JOUR TI - Population balance models: a useful complementary modelling framework for future WWTP modelling AU - Nopens, Ingmar AU - Torfs, Elena AU - Ducoste, Joel AU - Vanrolleghem, Peter A. AU - Gernaey, Krist V. T2 - WATER SCIENCE AND TECHNOLOGY AB - Population balance models (PBMs) represent a powerful modelling framework for the description of the dynamics of properties that are characterised by distributions. This distribution of properties under transient conditions has been demonstrated in many chemical engineering applications. Modelling efforts of several current and future unit processes in wastewater treatment plants could potentially benefit from this framework, especially when distributed dynamics have a significant impact on the overall unit process performance. In these cases, current models that rely on average properties cannot sufficiently capture the true behaviour and even lead to completely wrong conclusions. Examples of distributed properties are bubble size, floc size, crystal size or granule size. In these cases, PBMs can be used to develop new knowledge that can be embedded in our current models to improve their predictive capability. Hence, PBMs should be regarded as a complementary modelling framework to biokinetic models. This paper provides an overview of current applications, future potential and limitations of PBMs in the field of wastewater treatment modelling, thereby looking over the fence to other scientific disciplines. DA - 2015/// PY - 2015/// DO - 10.2166/wst.2014.500 VL - 71 IS - 2 SP - 159-167 SN - 1996-9732 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84923489194&partnerID=MN8TOARS KW - bubble size KW - distributed properties KW - floc size KW - PBM KW - product specifications KW - quality by design ER - TY - JOUR TI - In-use activity, fuel use, and emissions of heavy-duty diesel roll-off refuse trucks AU - Sandhu, Gurdas S. AU - Frey, H. Christopher AU - Bartelt-Hunt, Shannon AU - Jones, Elizabeth T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - The objectives of this study were to quantify real-world activity, fuel use, and emissions for heavy duty diesel roll-off refuse trucks; evaluate the contribution of duty cycles and emissions controls to variability in cycle average fuel use and emission rates; quantify the effect of vehicle weight on fuel use and emission rates; and compare empirical cycle average emission rates with the U.S. Environmental Protection Agency's MOVES emission factor model predictions. Measurements were made at 1 Hz on six trucks of model years 2005 to 2012, using onboard systems. The trucks traveled 870 miles, had an average speed of 16 mph, and collected 165 tons of trash. The average fuel economy was 4.4 mpg, which is approximately twice previously reported values for residential trash collection trucks. On average, 50% of time is spent idling and about 58% of emissions occur in urban areas. Newer trucks with selective catalytic reduction and diesel particulate filter had NOx and PM cycle average emission rates that were 80% lower and 95% lower, respectively, compared to older trucks without. On average, the combined can and trash weight was about 55% of chassis weight. The marginal effect of vehicle weight on fuel use and emissions is highest at low loads and decreases as load increases. Among 36 cycle average rates (6 trucks×6 cycles), MOVES-predicted values and estimates based on real-world data have similar relative trends. MOVES-predicted CO2 emissions are similar to those of the real world, while NOx and PM emissions are, on average, 43% lower and 300% higher, respectively. The real-world data presented here can be used to estimate benefits of replacing old trucks with new trucks. Further, the data can be used to improve emission inventories and model predictions.In-use measurements of the real-world activity, fuel use, and emissions of heavy-duty diesel roll-off refuse trucks can be used to improve the accuracy of predictive models, such as MOVES, and emissions inventories. Further, the activity data from this study can be used to generate more representative duty cycles for more accurate chassis dynamometer testing. Comparisons of old and new model year diesel trucks are useful in analyzing the effect of fleet turnover. The analysis of effect of haul weight on fuel use can be used by fleet managers to optimize operations to reduce fuel cost. DA - 2015/3// PY - 2015/3// DO - 10.1080/10962247.2014.990587 VL - 65 IS - 3 SP - 306-323 SN - 2162-2906 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84942103066&partnerID=MN8TOARS ER - TY - JOUR TI - Effect of column flange flexibility on WF-beam to rectangular CFT column connections AU - Yu, Yujie AU - Chen, Zhihua AU - Wang, Xiaodun T2 - JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH AB - Researches in the United States discovered different tension and shear flow patterns between wide flange (WF) column connections and box column connections. On the other hand, researches in Japan started many research on flexibility of column flange and proposed connection flexural moment strength based on the out-of-plane deformation for hollow section box column connections. However, both force flow pattern research and out-of-plane influence study in WF beam to rectangular concrete filled tube (CFT) column connections are insufficient. While due to the different composition and geometry configuration, direct extension of previous results is not feasible. This paper discusses the out-of-plane deformation at column flange, force flow pattern and shear and moment transfer efficiency of WF-beam to rectangular CFT column connection. Results show that both Poisson effect and flexibility of column flange will lead to a change on force flow pattern in beam–column junction region and inefficient moment transferring ability through beam web, resulting in a high level of hydrostatic stress demand at beam flanges. Weld access hole, thickness of column flange and diaphragm and web connection details all have certain effect on column flange bending stiffness and the transfer efficiency of beam web. A flexural strength evaluating method for the rectangular CFT column connection based on the out-of-plane deformation is also presented. DA - 2015/3// PY - 2015/3// DO - 10.1016/j.jcsr.2014.12.008 VL - 106 SP - 184-197 SN - 1873-5983 KW - WF beam to rectangular CFT column connection KW - Out-of-plane deformation KW - Shear flow KW - Web transfer efficiency KW - Flexural strength analysis ER - TY - JOUR TI - Deformation-Based Limit State Analysis of Embankment Dams Including Geometry and Water Level Effects AU - Khalilzad, Mahdi AU - Gabr, M. A. AU - Hynes, Mary Ellen T2 - International Journal of Geomechanics AB - The research presented in this paper is focused on the effect of various parameters on the deformation response of embankment dams and the corresponding performance limit states. The parameters considered include the geometry of the embankment and hydraulic loading in terms of intensity, duration, and cycles of loading and unloading as a result of the rise and fall of the water level in the reservoir. The analysis of a model embankment dam is conducted using the finite-element approach and the results are incorporated into simplified deformation-based probabilistic analyses. The effect of the change in geometry on shear strains and horizontal deformations and the corresponding probabilities of exceeding three predefined limit states are presented. The analyses are also used to demonstrate the importance of taking into account the storm loading history when assessing the stability of the flood protection earth structures under future flood events. In a larger embankment model, the shear zone propagates deeper for failure to occur. The time to exceed Limit States I, II, and III increases as the size of an embankment model becomes longer. For example, failure occurs after 4.6 days in a model with a size factor of 0.1 compared with 12 days for a model with a size factor of 0.2. This is mainly because the advancement of the saturation front to a critical level occurs in less time in the smaller embankment. DA - 2015/10// PY - 2015/10// DO - 10.1061/(asce)gm.1943-5622.0000435 VL - 15 IS - 5 SP - J2 - Int. J. Geomech. LA - en OP - SN - 1532-3641 1943-5622 UR - http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0000435 DB - Crossref KW - Limit state analysis KW - Slope stability KW - Embankment dams KW - Probability of failure ER - TY - JOUR TI - Characterization of mechanical behavior of asphalt mixtures under partial triaxial compression test AU - Zhang, Jiantong AU - Yang, Jun AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The principle and procedures of partial triaxial compression test (PTCT) was introduced. The appropriate diameter and height of specimen and platen were determined for PTCT requirement. Three types of mixtures were tested by PTCT at a temperature of 60 °C. Stress–strain results indicate that the response of asphalt mixtures to various test conditions by PTCT is in accordance with that of typical triaxial compression tests. Also, both PTCT and traditional triaxial compression test represent the similar deformation characteristics of asphalt mixtures. The PTCT inherits many advantages possessed by the triaxial test, and is easier to be carried out considering the simplicity of experimental equipment, specimen preparation, and test operation. DA - 2015/3/15/ PY - 2015/3/15/ DO - 10.1016/j.conbuildmat.2014.12.085 VL - 79 SP - 136-144 SN - 1879-0526 KW - Asphalt mixture KW - Partial triaxial compression test KW - Finite element modeling KW - High-temperature performance KW - Stress-strain relationship ER - TY - JOUR TI - Understanding the low-frequency variability in hydroclimatic attributes over the southeastern US AU - Wang, Hui AU - Sankarasubramanian, A. AU - Ranjithan, R. S. T2 - JOURNAL OF HYDROLOGY AB - Most studies on evaluating the potential in developing seasonal to interannual hydroclimatic forecasts have focused on associating low-frequency climatic conditions with basin-level precipitation/streamflow. The motivation of this study is to provide an understanding on how land surface characteristics modulate the low-frequency (interannual to decadal) variability in precipitation to develop low-frequency signal in streamflow. For this purpose, we consider basins with minimum anthropogenic impacts over southeastern United States and apply Singular Spectrum Analysis (SSA), a data-driven spectrum analysis tool, on annual precipitation and streamflow time series for detecting the dominant frequencies and for estimating the associated variability with them. Hypothesis test against an AR(1) process is carried out via Monte Carlo SSA for detecting significant (at 90% confidence level) low-frequency oscillations. Thus, the study investigates how the observed low-frequency oscillations in precipitation/streamflow vary over the southeastern United States and also their associations with climatic conditions. For most study basins, precipitation exhibits higher low-frequency oscillations than that of streamflow primarily due to reduction in variability by basin storage. Investigating this further, we found that the percentage variance accounted by low-frequency oscillations in streamflow being higher for larger basins which primarily indicates the increased role of climate and basin storage. To develop a fundamental understanding on how basin storage controls the low-frequency oscillations in streamflow, a simple annual hydrological model is employed to explore how the given low-frequency signal in precipitation being modified under different baseflow index conditions and groundwater residence time. Implications of these analyses relating to streamflow predictions and model calibration are also discussed. DA - 2015/2// PY - 2015/2// DO - 10.1016/j.jhydrol.2014.09.081 VL - 521 SP - 170-181 SN - 1879-2707 KW - Interannual variability KW - Decadal oscillations KW - Singular Spectrum Analysis KW - Basin storage effect KW - Water management ER - TY - JOUR TI - Method for investigating intradriver heterogeneity using vehicle trajectory data: A Dynamic Time Warping approach AU - Taylor, Jeffrey AU - Zhou, Xuesong AU - Rouphail, Nagui M. AU - Porter, Richard J. T2 - TRANSPORTATION RESEARCH PART B-METHODOLOGICAL AB - After first extending Newell’s car-following model to incorporate time-dependent parameters, this paper describes the Dynamic Time Warping (DTW) algorithm and its application for calibrating this microscopic simulation model by synthesizing driver trajectory data. Using the unique capabilities of the DTW algorithm, this paper attempts to examine driver heterogeneity in car-following behavior, as well as the driver’s heterogeneous situation-dependent behavior within a trip, based on the calibrated time-varying response times and critical jam spacing. The standard DTW algorithm is enhanced to address a number of estimation challenges in this specific application, and a numerical experiment is presented with vehicle trajectory data extracted from the Next Generation Simulation (NGSIM) project for demonstration purposes. The DTW algorithm is shown to be a reasonable method for processing large vehicle trajectory datasets, but requires significant data reduction to produce reasonable results when working with high resolution vehicle trajectory data. Additionally, singularities present an interesting match solution set to potentially help identify changing driver behavior; however, they must be avoided to reduce analysis complexity. DA - 2015/3// PY - 2015/3// DO - 10.1016/j.trb.2014.12.009 VL - 73 SP - 59-80 SN - 0191-2615 KW - Dynamic Time Warping KW - Car-following model KW - Driver behavior heterogeneity KW - Vehicle trajectory data ER - TY - JOUR TI - Electrical resistance tomography to monitor unsaturated moisture flow in cementitious materials AU - Hallaji, Milad AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - CEMENT AND CONCRETE RESEARCH AB - Traditionally the electrically-based assessment of the moisture flow in cement-based materials relies on two- or four-point measurements. In this paper, imaging of moisture distribution with electrical resistance tomography (ERT) is considered. Especially, the aim is to study whether ERT could give information on unsaturated moisture flows in cases where the flow is non-uniform. In the experiment, the specimens are monitored with ERT during the water ingress. The ERT reconstructions are compared with neutron radiographs, which provide high resolution information on the 2D distribution of the moisture. The results indicate that ERT is able to detect the moisture movement and to show approximately the shape and position of the water front even if the flow is nonuniform. DA - 2015/3// PY - 2015/3// DO - 10.1016/j.cemconres.2014.11.007 VL - 69 SP - 10-18 SN - 1873-3948 KW - Concrete KW - Electrical Resistance Tomography (ERT) KW - Image Analysis KW - Transport Properties ER - TY - JOUR TI - Driver behavior in use of guide and logo signs under distraction and complex roadway conditions AU - Kaber, David AU - Pankok, Carl, Jr. AU - Corbett, Brendan AU - Ma, Wenqi AU - Hummer, Joseph AU - Rasdorf, William T2 - APPLIED ERGONOMICS AB - White-on-blue logo signs on the sides of highways are typically used to notify drivers of food, gas, and lodging at an upcoming interchange. The current research assessed driver performance and attention allocation in a simulated freeway driving task when exposed to six-panel logo signs, nine-panel logo signs, mileage guide signs, and roadway work zones both with and without an in-car navigation device. The objective was to identify the impact of signage types on driver behavior under realistic driving conditions. Results revealed glance durations and fixation frequencies to guide signs to be significantly lower than with six-panel and nine-panel logo signs, but no differences were found between six-panel and nine-panel logo signs. There were also statistical differences among the independent variables for speed deviation and lane deviation, but magnitudes were not large enough to be considered practically significant in terms of driving safety. Overall, there were minor differences in sign processing time between logo signs and mileage guide signs, but such differences did not translate to degradations in vehicle control. DA - 2015/3// PY - 2015/3// DO - 10.1016/j.apergo.2014.09.005 VL - 47 SP - 99-106 SN - 1872-9126 KW - Roadway logo signs KW - Driver performance KW - Driver distraction ER - TY - JOUR TI - Computational fluid dynamics modeling alternatives for UV-initiated advanced oxidation processes AU - Ducoste, Joel J. AU - Alpert, Scott M. T2 - WATER QUALITY RESEARCH JOURNAL OF CANADA AB - Design and optimization of ultraviolet-initiated (UV-initiated) advanced oxidation processes (AOPs) using hydrogen peroxide (H2O2) must consider both system configuration and chemical kinetics. Alternative approaches to modeling AOP systems have been proposed in the literature; yet, due to the complex nature of the reactions involved, the literature lacks clarity in the appropriate selection of a modeling approach to help define the UV/AOP system performance. Computational fluid dynamics (CFD) was compared to the numerical solution of a system of ordinary differential equations describing the reaction mechanism for hydroxyl radical production and methylene blue destruction and to a UV dose distribution analysis produced by a Lagrangian particle track in CFD with a given dose–response curve. Similar analyses were also performed to simulate the destruction of tris(2-chloroethyl) phosphate (TCEP) and tributyl phosphate (TBP), in two different photoreactors. To validate the simulations, the results of the models were compared to pilot reactor trials for methylene blue bleaching and literature data for TCEP and TBP. Modeling results suggest that the agreement of both CFD Eulerian and Lagrangian approaches to simulating the UV/H2O2 AOP is a function of reactor design, the water matrix, and operating conditions. DA - 2015/// PY - 2015/// DO - 10.2166/wqrjc.2014.035 VL - 50 IS - 1 SP - 4-20 SN - 1201-3080 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84961377595&partnerID=MN8TOARS KW - computational fluid dynamics KW - fluid dynamics KW - numerical models KW - oxidation KW - water treatment ER - TY - JOUR TI - Comparison of Sources of Variability in School Age Children Exposure to Ambient PM2.5 AU - Che, W. W. AU - Frey, H. Christopher AU - Lau, Alexis K. H. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - School age children are particularly susceptible to exposure to ambient fine particle (PM2.5). To provide insight into factors affecting variability in ambient PM2.5 exposure, distributions of daily PM2.5 exposures for school age children are estimated for four seasons in three climatic zones of the United States using a stochastic microenvironmental exposure model, based on ambient concentration, air exchange rate, penetration factor, deposition rate, census data, meteorological data, and time pattern data. Estimated daily individual exposure varies largely among seasons, regions, and individuals. The mean ratio of ambient exposure to ambient concentration (Ea/Ca) ranges from 0.46 to 0.61 among selected regions and seasons, resulting from differences in air exchange rate. The individual Ea/Ca varies by a factor of 2 to 3 over a 95% frequency range among simulated children, resulting from variability in children’s time patterns. These patterns are similar among age groups, but vary with the day of the week and outdoor temperature. Variability in exposure is larger between individuals than between groups. The high end ratio of the Ea/Ca, at the 95th percentile of inter-individual variability, is 30% to 50% higher than the mean Ea/Ca ratio. Results can be used to intepret and adjust exposure errors in epidemiology and to assist in development of exposure mitigation strategies. DA - 2015/2/3/ PY - 2015/2/3/ DO - 10.1021/es506275c VL - 49 IS - 3 SP - 1511-1520 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84964267743&partnerID=MN8TOARS ER - TY - JOUR TI - Characterization of Uncertainty in Estimation of Methane Collection from Select US Landfills AU - Wang, Xiaoming AU - Nagpure, Ajay S. AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Methane is a potent greenhouse gas generated from the anaerobic decomposition of waste in landfills. If captured, methane can be beneficially used to generate electricity. To inventory emissions and assist the landfill industry with energy recovery projects, the U.S. EPA developed the Landfill Gas Emissions Model (LandGEM) that includes two key parameters: the first-order decay rate (k) and methane production potential (L0). By using data from 11 U.S. landfills, Monte Carlo simulations were performed to quantify the effect of uncertainty in gas collection efficiency and municipal solid waste fraction on optimal k values and collectable methane. A dual-phase model and associated parameters were also developed to evaluate its performance relative to a single-phase model (SPM) similar to LandGEM. The SPM is shown to give lower error in estimating methane collection, with site-specific best-fit k values. Most of the optimal k values are notably greater than the U.S. EPA's default of 0.04 yr(-1), which implies that the gas generation decreases more rapidly than predicted at the current default. We translated the uncertainty in collectable methane into uncertainty in engine requirements and potential economic losses to demonstrate the practical significance to landfill operators. The results indicate that landfill operators could overpay for engine capacity by $30,000-780,000 based on overestimates of collectable methane. DA - 2015/2/3/ PY - 2015/2/3/ DO - 10.1021/es505268x VL - 49 IS - 3 SP - 1545-1551 SN - 1520-5851 ER - TY - JOUR TI - Case Studies of the Allocation and Reduction of Time Buffer through Use of the Last Planner System AU - Russell, Marion M. AU - Liu, Min AU - Howell, Gregory AU - Hsiang, Simon M. T2 - Journal of Construction Engineering and Management AB - Buffers are used in construction to absorb variation caused by the inherent complexity and uncertainty present in construction projects. The case studies presented here focus on time buffer added to construction task durations. For this research, time buffer is defined as extra time added during planning to individual task durations to compensate for uncertainty and protect against workflow variation. Two case studies were conducted with one involving a mechanical contractor and the other involving a large general contractor. This research contributes to the body of knowledge by: (1) investigating the time buffer impact on project performance; (2) empirically demonstrating the effect of last planner system (LPS) on reducing time buffer and increasing percent planned complete (PPC); and (3) examining the buffer trends of different trades and activity types. The findings demonstrate LPS as an example of an effective planning strategy for construction managers in improving project performance and help them understand what drives the need for buffer in their construction schedules, allowing efforts focused on strategically addressing the most critical areas of concern and uncertainty. DA - 2015/2// PY - 2015/2// DO - 10.1061/(asce)co.1943-7862.0000900 VL - 141 IS - 2 SP - 04014068 J2 - J. Constr. Eng. Manage. LA - en OP - SN - 0733-9364 1943-7862 UR - http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000900 DB - Crossref KW - Construction KW - Planning KW - Uncertainty KW - Buffer KW - Labor and personnel issues ER - TY - JOUR TI - Analysis of material recovery facilities for use in life-cycle assessment AU - Pressley, Phillip N. AU - Levis, James W. AU - Damgaard, Anders AU - Barlaz, Morton A. AU - DeCarolis, Joseph F. T2 - Waste Management AB - Insights derived from life-cycle assessment of solid waste management strategies depend critically on assumptions, data, and modeling at the unit process level. Based on new primary data, a process model was developed to estimate the cost and energy use associated with material recovery facilities (MRFs), which are responsible for sorting recyclables into saleable streams and as such represent a key piece of recycling infrastructure. The model includes four modules, each with a different process flow, for separation of single-stream, dual-stream, pre-sorted recyclables, and mixed-waste. Each MRF type has a distinct combination of equipment and default input waste composition. Model results for total amortized costs from each MRF type ranged from $19.8 to $24.9 per Mg (1Mg=1 metric ton) of waste input. Electricity use ranged from 4.7 to 7.8kWh per Mg of waste input. In a single-stream MRF, equipment required for glass separation consumes 28% of total facility electricity consumption, while all other pieces of material recovery equipment consume less than 10% of total electricity. The dual-stream and mixed-waste MRFs have similar electricity consumption to a single-stream MRF. Glass separation contributes a much larger fraction of electricity consumption in a pre-sorted MRF, due to lower overall facility electricity consumption. Parametric analysis revealed that reducing separation efficiency for each piece of equipment by 25% altered total facility electricity consumption by less than 4% in each case. When model results were compared with actual data for an existing single-stream MRF, the model estimated the facility's electricity consumption within 2%. The results from this study can be integrated into LCAs of solid waste management with system boundaries that extend from the curb through final disposal. DA - 2015/1// PY - 2015/1// DO - 10.1016/j.wasman.2014.09.012 VL - 35 SP - 307-317 J2 - Waste Management LA - en OP - SN - 0956-053X UR - http://dx.doi.org/10.1016/j.wasman.2014.09.012 DB - Crossref KW - Recycling KW - Material recovery facility KW - Life-cycle assessment KW - Municipal solid waste ER - TY - JOUR TI - Using Telepresence for Real-Time Monitoring of Construction Operations AU - Jaselskis, Edward AU - Sankar, Arvind AU - Yousif, Ahmad AU - Clark, Brett AU - Chinta, Viswa T2 - Journal of Management in Engineering AB - This paper discusses a novel approach related to monitoring construction projects in the field, allowing for site-based personnel to be reduced and expert opinions to be obtained without a physical site presence. The idea involves bonded streaming capability for live video and audio from mobile cameras anywhere on a construction site to team members located off site. True bonded wireless air card technology provides sufficient bandwidth to transmit high-quality video and audio transmissions. Remotely located team members can visually instruct and guide the operator of the portable video camera equipment around the site to accomplish their duties in a telepresent or virtual fashion (e.g., performing remote site safety inspections, progress updates, or quality inspections), thereby saving the time and cost of physical site visits. Numerous case studies using this approach were conducted on a variety of project types, including residential, commercial, and transportation. Results from user feedback indicate that this approach has promise as an effective management tool. This paper describes the equipment and its application for remote monitoring and management of construction operations, case study projects, participant feedback, implementation costs, and benefits and limitations. DA - 2015/1// PY - 2015/1// DO - 10.1061/(ASCE)ME.1943-5479.0000336 VL - 31 IS - 1 J2 - J. Manage. Eng. LA - en OP - SN - 0742-597X 1943-5479 UR - http://dx.doi.org/10.1061/(ASCE)ME.1943-5479.0000336 DB - Crossref KW - Telepresence KW - Bonded technology KW - Remote site inspections and management ER - TY - JOUR TI - Measurement of chemical leaching potential of sulfate from landfill disposed sulfate containing wastes AU - Sun, Wenjie AU - Barlaz, Morton A. T2 - WASTE MANAGEMENT AB - A number of sulfate-containing wastes are disposed in municipal solid wastes (MSW) landfills including residues from coal, wood, and MSW combustion, and construction and demolition (C&D) waste. Under anaerobic conditions that dominate landfills, the sulfate can be reduced to hydrogen sulfide which is problematic for several reasons including its low odor threshold, toxicity, and corrosive nature. The overall objective of this study was to evaluate existing protocols for the quantification of total leachable sulfate from solid samples and to compare their effectiveness and efficiency with a new protocol described in this study. Methods compared include two existing acid extraction protocols commonly used in the U.S., a pH neutral protocol that requires multiple changes of the leaching solution, and a new acid extraction method. The new acid extraction method was shown to be simple and effective to measure the leaching potential of sulfate from a range of landfill disposed sulfate-containing wastes. However, the acid extraction methods do not distinguish between sulfate and other forms of sulfur and are thus most useful when sulfate is the only form of sulfur present. DA - 2015/2// PY - 2015/2// DO - 10.1016/j.wasman.2014.11.014 VL - 36 SP - 191-196 SN - 0956-053X KW - Hydrogen sulfide KW - Sulfate-containing wastes KW - Municipal solid waste KW - Landfill ER -