TY - CONF TI - Procedure for real-world measurement and data analysis of a flex fuel vehicle operated on E85 AU - Delavarrafiee, M. AU - Frey, H.C. C2 - 2016/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2016/// VL - 4 SP - 2689-2714 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014816584&partnerID=MN8TOARS ER - TY - CONF TI - Gasoline vehicle fuel efficiency and emissions for gas-direct injection versus port-fuel injection AU - Singh, S. AU - Frey, H.C. C2 - 2016/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2016/// VL - 4 SP - 2823-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014864810&partnerID=MN8TOARS ER - TY - CONF TI - Assessing the impact of real-world driving cycles, fuel economy and tailpipe exhaust emissions on eco-rating of passenger cars AU - Rastogi, N. AU - Frey, H.C. C2 - 2016/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2016/// VL - 4 SP - 2758-2783 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014833745&partnerID=MN8TOARS ER - TY - JOUR TI - Comparing actual de facto wastewater reuse and its public acceptability: A three city case study AU - Rice, Jacelyn AU - Wutich, Amber AU - White, Dave D. AU - Westerhoff, Paul T2 - Sustainable Cities and Society AB - Increases in water treatment technology have made water recycling a viable engineering solution to water supply limitations. In spite of this, such water recycling schemes have often been halted by lack of public acceptance. Previous studies have captured the public’s attitudes regarding planned reuse schemes, but here we focus on unplanned reuse (i.e. de facto reuse), present in many cities across the U.S. We performed a survey in three metropolitan areas, Atlanta, GA (N = 421), Philadelphia, PA (N = 490), and Phoenix, AZ (N = 418), to assess basic perceptions of treated wastewater occurrence and its acceptance in the public water supply. These perceptions were then coupled by estimates of the actual extent of occurrence in the corresponding cities. The key results are that (1) de facto reuse occurs at rates across the three cities higher than what is perceived; (2) roughly 25% of respondents perceive de facto reuse to occur in their home tap water; and (3) respondents who perceived de facto reuse to occur at their tap were ten times more likely to have a high level of acceptance for de facto reuse in their home tap. DA - 2016/// PY - 2016/// DO - 10.1016/j.scs.2016.06.007 VL - 27 SP - 467-474 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84977124949&partnerID=MN8TOARS ER - TY - CONF TI - Proposed Anchoring Systems for Gulf Stream (Gs) Renewable Energy Devices Accounting for Potential of GS Meandering AU - Ahsanuzzaman, Md AU - Gabr, M.A. T2 - 3rd Marine Energy Technical Symposium, National Hydropower Association C2 - 2016/4// C3 - 3rd Marine Energy Technical Symposium, National Hydropower Association CY - Washington, DC DA - 2016/4// PY - 2016/4// ER - TY - JOUR TI - Highway Retaining Walls are Assets: A Risk-Based Approach for Managing Them AU - Gabr, Mo AU - Butler, Cedrick AU - Rasdorf, William AU - Findley, Daniel J. AU - Bert, Steven A. T2 - GEOSTRATA Magazine AB - Throughout history, retaining walls (RWs) have served a vital role in supporting civil infrastructure. The ruins of dry stone walls that purportedly supported the hills and slopes of ancient Rome can be seen today in the underground corridors of the Colosseum, and within the ruins of the Forum and Circus Maximus. Within our National Highway System, retaining walls are an integral part of bridge abutments, grade separations, and highway embankments, and in many situations are used to support and protect transportation assets such as roads, rivers, and railways. Compared to pavements and bridges, retaining walls require less maintenance. However, and perhaps due to such success, records of wall construction, design, and performance are minimal. DA - 2016/3// PY - 2016/3// DO - 10.1061/geosek.0000320 VL - 20 IS - 2 SP - 66-72 J2 - Geostrata LA - en OP - SN - 1529-2975 2766-9122 UR - http://dx.doi.org/10.1061/geosek.0000320 DB - Crossref ER - TY - JOUR TI - Correlation of dynamic cone penetrometer index to proof roller test to assess subgrade soils stabilization criterion AU - Mousavi, S. Hamed AU - Gabr, Mohammed A. AU - Borden, Roy H. T2 - International Journal of Geotechnical Engineering AB - The proof roller test has been traditionally carried out as a technique for subgrade quality assessment in road construction and the induced pumping and permanent deformation are used as the basis for subgrade’s pass/fail criteria. The objective of the study presented herein is to assess the feasibility of using the dynamic cone penetrometer index, DCPI, to discern the need for undercut and the quality of subgrade. A series of 3D FEM analysis was performed to develop a subgrade stabilization recommendation chart, based on the predicted properties from DCPI and deformation response under cyclic proof roll loading. The ‘not passing’ criterion (will be referred to herein as ‘failure’ criterion) was determined as a 25 mm permanent deformation under proof roll test. It was determined that the failure deformation occurs at DCPI value of 38 mm/blow for single layer subgrade soil with the Mr/E50 of 6, ratio of resilient modulus to the secant modulus at 50% shear failure. These results are consistent with NCDOT 38... DA - 2016/12/27/ PY - 2016/12/27/ DO - 10.1080/19386362.2016.1272751 VL - 12 IS - 3 SP - 284-292 J2 - International Journal of Geotechnical Engineering LA - en OP - SN - 1938-6362 1939-7879 UR - http://dx.doi.org/10.1080/19386362.2016.1272751 DB - Crossref ER - TY - CONF TI - Response of Water Systems under Extreme Events: A Comprehensive Approach to Modeling Water System Resilience AU - Chmielewski, Hana AU - Guidotti, Roberto AU - McAllister, Therese AU - Gardoni, Paolo T2 - World Environmental and Water Resources Congress 2016 AB - Water systems (e.g., potable water, wastewater, and storm water systems) are regarded as “lifeline” infrastructure. Their disruption can cause cascading effects, influencing the economy of an entire region. Past hazard events show that water availability is crucial for minimizing the societal impact of such events and for recovery processes. To date, stochastic simulations of hazards events, and their direct and indirect physical damage to water system components, are typically not coupled with hydraulic simulations of functionality loss and restoration, including water quality, pressure, and flow throughout the network. This work presents a comprehensive approach to the modeling of water system resilience subject to a seismic event; however, the procedure is general and can be applied to other network systems and hazards. The model performs: (1) a baseline deterministic hydraulic analysis on an undamaged water system, focusing on meaningful functionality metrics, (i.e., water pressure, quantity, and quality); (2) a probabilistic analysis of the damaged system considering the damage state and the performance level of each component; (3) a probabilistic analysis of the water system functionality, considering the physical damage analysis and the recovery time of each component. C2 - 2016/5/16/ C3 - World Environmental and Water Resources Congress 2016 DA - 2016/5/16/ DO - 10.1061/9780784479865.050 PB - American Society of Civil Engineers UR - http://dx.doi.org/10.1061/9780784479865.050 ER - TY - JOUR TI - Modeling the resilience of critical infrastructure: the role of network dependencies AU - Guidotti, Roberto AU - Chmielewski, Hana AU - Unnikrishnan, Vipin AU - Gardoni, Paolo AU - McAllister, Therese AU - van de Lindt, John T2 - Sustainable and Resilient Infrastructure AB - Water and wastewater network, electric power network, transportation network, communication network, and information technology network are among the critical infrastructure in our communities; their disruption during and after hazard events greatly affects communities’ well-being, economic security, social welfare, and public health. In addition, a disruption in one network may cause disruption to other networks and lead to their reduced functionality. This paper presents a unified theoretical methodology for the modeling of dependent/interdependent infrastructure networks and incorporates it in a six-step probabilistic procedure to assess their resilience. Both the methodology and the procedure are general, can be applied to any infrastructure network and hazard, and can model different types of dependencies between networks. As an illustration, the paper models the direct effects of seismic events on the functionality of a potable water distribution network and the cascading effects of the damage of the electric power network (EPN) on the potable water distribution network (WN). The results quantify the loss of functionality and delay in the recovery process due to dependency of the WN on the EPN. The results show the importance of capturing the dependency between networks in modeling the resilience of critical infrastructure. DA - 2016/11/28/ PY - 2016/11/28/ DO - 10.1080/23789689.2016.1254999 VL - 1 IS - 3-4 SP - 153-168 J2 - Sustainable and Resilient Infrastructure LA - en OP - SN - 2378-9689 2378-9697 UR - http://dx.doi.org/10.1080/23789689.2016.1254999 DB - Crossref ER - TY - CONF TI - Predicting the Shear Strength of Thick Slabs AU - Collins, M.P. AU - Bentz, E.C. AU - Quach, P.T. AU - Proestos, G.T. T2 - fib International Workshop on Beam Shear C2 - 2016/9/5/ C3 - fib International Workshop on Beam Shear CY - Zurich, Switzerland DA - 2016/9/5/ PY - 2016/9/5/ SP - 269–282 ER - TY - JOUR TI - Supplementary material to "Quantifying the volatility of organic aerosol in the southeastern U.S." AU - Saha, Provat K. AU - Khlystov, Andrey AU - Yahya, Khairunnisa AU - Zhang, Yang AU - Xu, Lu AU - Ng, Nga L. AU - Grieshop, Andrew P. DA - 2016/8/9/ PY - 2016/8/9/ DO - 10.5194/acp-2016-575-supplement VL - 8 UR - https://doi.org/10.5194/acp-2016-575-supplement ER - TY - JOUR TI - Quantifying the volatility of organic aerosol in the southeastern U.S. AU - Saha, Provat K. AU - Khlystov, Andrey AU - Yahya, Khairunnisa AU - Zhang, Yang AU - Xu, Lu AU - Ng, Nga L. AU - Grieshop, Andrew P. AB - Abstract. The volatility of organic aerosols (OA) has emerged as a property of primary importance in understanding their atmospheric lifecycle, and thus abundance and transport. However, quantitative estimates of the thermodynamic (volatility) and kinetic parameters dictating ambient OA gas-particle partitioning, such as saturation concentrations (C*), enthalpy of evaporation (ΔHvap) and evaporation coefficient (γe), are highly uncertain. Here, we present measurements of ambient OA volatility at two sites in the southeastern U.S., one at biogenic-volatile-organic-compound (BVOC)-dominated rural setting in Alabama as part of the Southern Oxidant and Aerosol Study (SOAS) in June–July, 2013, and another at a more anthropogenically-influenced urban location in North Carolina during October–November, 2013. These measurements applied a dual-thermodenuder (TD) system, in which temperature and residence times are varied in parallel, to constrain equilibrium and kinetic aerosol volatility properties. Gas-particle partitioning parameters were determined via evaporation kinetic model fits to the dual-TD observations. OA volatility parameters values derived from both datasets were similar despite the fact that measurements were collected in distinct settings and seasons. The OA volatility distributions also did not vary dramatically over the campaign period nor strongly correlate with OA components identified via positive matrix factorization of aerosol mass spectrometer data. A large portion (40–70 %) of measured ambient OA at both sites was composed of very low volatility organics (C*≤ 0.1 μg m−3). An effective ΔHvap of bulk OA of ~ 80–100 kJ mol−1 and a γe value of ~ 0.5 best describe the evaporation observed in the TDs. This range of ΔHvap values is substantially higher than that typically assumed for simulating OA in atmospheric models (30–40 kJ mol−1). TD data indicate that γe is on the order of 0.1 to 0.5, indicating that repartitioning timescales for atmospheric OA are on the order of several minutes to an hour under atmospheric conditions. The OA volatility distributions resulting from fits were compared to those simulated in the Weather, Research and Forecasting model with Chemistry (WRF/Chem) with a current treatment of SOA formation. The substantial fraction of low-volatility material observed in our measurements is largely missing from simulations, and OA mass concentrations are underestimated. The large discrepancies between simulations and observations indicate a need to treat low volatility OA in atmospheric models. Volatility parameters extracted from ambient measurements enable evaluation of emerging treatments for OA (e.g., secondary OA using the volatility basis set or formed via aqueous chemistry) in atmospheric models. DA - 2016/8/9/ PY - 2016/8/9/ DO - 10.5194/acp-2016-575 VL - 8 UR - https://doi.org/10.5194/acp-2016-575 ER - TY - JOUR TI - Surface modification of activated carbon for enhanced adsorption of perfluoroalkyl acids from aqueous solutions AU - Zhi, Y. AU - Liu, J. T2 - Chemosphere AB - The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA. DA - 2016/// PY - 2016/// DO - 10.1016/j.chemosphere.2015.09.097 VL - 144 SP - 1224-1232 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84953791076&partnerID=MN8TOARS KW - PFOS KW - PFOA KW - Activated carbon KW - Activated carbon fibers KW - Basicity KW - Surface modification ER - TY - CONF TI - Photochemical Micro-sensors for Evaluating Light Distribution within Photosyntheitic Biioreactors for Biofuels Production AU - Karam, A. AU - de los Reyes, F.L., III AU - Levis, J. AU - Ranjithan, R. AU - Ducoste, J. T2 - 6th International Conference on Algal Biomass and Bioproducts C2 - 2016/6/26/ CY - San Diego, CA DA - 2016/6/26/ PY - 2016/6/26/ ER - TY - SOUND TI - Computational prediction of regulatory relationships: New players 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 - 2016/7// PY - 2016/7// ER - TY - SOUND TI - Clustering and Differential Alignment Algorithm: Identification of Early Stage Regulators in the A. thaliana Iron Deficiency Response AU - Williams, Cranos AU - Koryachko, Alexandr AU - Matthiadis, Anna AU - Muhammad, Durreshahwar AU - Foret, Jessica AU - Brady, Siobhan M. AU - Ducoste, Joel AU - Tuck, James AU - Long, Terri A. DA - 2016/3// PY - 2016/3// ER - TY - CONF TI - Determining the fate of Long Chain Free Fatty Acids and Fats, Oils and Grease in Sewer Collection Systems using a double waveband FTIR technique AU - Malyala, D. AU - Hao, Z. AU - Ducoste, J. T2 - North Carolina Section of the American Water Works Association (NCAWWA)-Water Environment Association (WEA) C2 - 2016/11/13/ CY - Raleigh, NC DA - 2016/11/13/ PY - 2016/11/13/ ER - TY - SOUND TI - Understanding and Predicting Temperatures in Municipal Solid Waste Landfills AU - Hao, Z. AU - Sun, M. AU - Ducoste, J. AU - Barlaz, M. AU - Benson, C. AU - Castaldi, M. AU - Luettich, S. DA - 2016/1/31/ PY - 2016/1/31/ ER - TY - CONF TI - Determination of Long Chain Free Fatty Acid (LCFFA) in Wastewater Using a Novel Double Wavenumber FTIR Technique for the Protection of Sanitary Sewer Collection Systems AU - Hao, Z. AU - Malyala, D. AU - Ducoste, J. T2 - North Carolina Section of the American Water Works Association (NCAWWA)-Water Environment Association (WEA) C2 - 2016/11/13/ CY - Raleigh, NC DA - 2016/11/13/ PY - 2016/11/13/ ER - TY - SOUND TI - Directing microbial community assembly in anaerobic reactors: implications for increasing methane yields and improving start-up AU - de los Reyes, F. L., III AU - Wang, L. AU - Shen, P. AU - Yeh, J. AU - Aziz, T. AU - Ducoste, J.J. DA - 2016/3/17/ PY - 2016/3/17/ ER - TY - CONF TI - Inducing Aerobic Granular Sludge Formation Through Unevenly Distributed Hydrodynamic Shear Rates AU - Weaver, J.E. AU - Ducoste, J.J. AU - de los Reyes, F.L. T2 - North Carolina Section of the American Water Works Association (NCAWWA)-Water Environment Association (WEA) C2 - 2016/11/13/ CY - Raleigh, NC DA - 2016/11/13/ PY - 2016/11/13/ ER - TY - SOUND TI - Drinking Water Treatment: What Happens from Source to Tap AU - Ducoste, J.J. DA - 2016/// PY - 2016/// ER - TY - SOUND TI - Game Changer: A New Technique for Measuring the Performance of Grease Interceptors AU - Ducoste, J.J. DA - 2016/// PY - 2016/// ER - TY - SOUND TI - Grease Removal Devices: Challenges in the Removal of FOG Emulsions and the Impact of Food Service Establishment Operations AU - Ducoste, J.J. DA - 2016/// PY - 2016/// ER - TY - JOUR TI - Application of viscoelastic continuum damage approach to predict fatigue performance of Binzhou perpetual pavements AU - Cao, Wei AU - Norouzi, Amirhossein AU - Kim, Y. Richard T2 - Journal of Traffic and Transportation Engineering (English Edition) AB - For this study, the Binzhou perpetual pavement test sections constructed in Shandong Province, China, were simulated for long-term fatigue performance using the layered viscoelastic pavement analysis for critical distresses (LVECD) finite element software package. In this framework, asphalt concrete was treated in the context of linear viscoelastic continuum damage theory. A recently developed unified fatigue failure criterion that defined the boundaries of the applicable region of the theory was also incorporated. The mechanistic modeling of the fatigue mechanisms was able to accommodate the complex temperature variations and loading conditions of the field pavements in a rigorous manner. All of the material models were conveniently characterized by dynamic modulus tests and direct tension cyclic fatigue tests in the laboratory using cylindrical specimens. By comparing the obtained damage characteristic curves and failure criteria, it is found that mixtures with small aggregate particle sizes, a dense gradation, and modified asphalt binder tended to exhibit the best fatigue resistance at the material level. The 15-year finite element structural simulation results for all the test sections indicate that fatigue performance has a strong dependence on the thickness of the asphalt pavements. Based on the predicted location and severity of the fatigue damage, it is recommended that Sections 1 and 3 of the Binzhou test sections be employed for perpetual pavement design. DA - 2016/4// PY - 2016/4// DO - 10.1016/J.JTTE.2016.03.002 VL - 3 IS - 2 SP - 104-115 J2 - Journal of Traffic and Transportation Engineering (English Edition) LA - en OP - SN - 2095-7564 UR - http://dx.doi.org/10.1016/J.JTTE.2016.03.002 DB - Crossref KW - Perpetual pavement KW - Fatigue cracking KW - Continuum damage theory KW - Failure criterion KW - LVECD ER - TY - JOUR TI - Behavior of Free and Connected Double-Tee Flanges Reinforced with carbon-fiber-reinforced polymer AU - Botros, A. AU - Lucier, G. AU - Rizkalla, S. AU - Gleich, H. T2 - PCI Journal DA - 2016/9// PY - 2016/9// ER - TY - JOUR TI - Use of carbon-fiber-reinforced polymer grid for precast concrete piles AU - Seliem, H. AU - Ding, L. AU - Potter, W. AU - Rizkalla, S. T2 - PCI Journal DA - 2016/9// PY - 2016/9// ER - TY - JOUR TI - Improving the Durability and Coastal Bridges with CFRP Prestressed Cored Slabs AU - Shapack, G. AU - Van Brunt, Z. AU - Seracino, R. AU - Lucier, G. AU - Rizkalla, S. AU - Pour-Ghaz, M. T2 - ACI Special publications DA - 2016/4// PY - 2016/4// ER - TY - JOUR TI - Spatial and temporal variability in dune field: Pea Island, North Carolina AU - Sciaudone, E.J. AU - Velasquez-Montoya, L. AU - Smyre, E.A. AU - Overton, M.F. T2 - Shore & Beach, Coastal Observations DA - 2016/// PY - 2016/// VL - 84 IS - 2 SP - 49-58 ER - TY - RPRT TI - Survey of Existing VOC Treatment Installations AU - Chowdhury, Z. AU - Porter, K.L. AU - Collins, J. AU - Francis, C. AU - Sriboonlue, S. AU - Cornwell, D. AU - Brown, R. AU - Knappe, D.R.U. A3 - Water Research Foundation DA - 2016/// PY - 2016/// M1 - 4453 M3 - Executive Summary PB - Water Research Foundation SN - 4453 ER - TY - CONF TI - How Much Methane is Emitted from Landfills? A Comparison of Field Measurements to Gas Production Models AU - De la Cruz, F.B. AU - Green, R.B. AU - Hater, G.R. AU - Chanton, J.P. AU - Thoma, E.D. AU - Harvey, T.A. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - CONF TI - Proactive Development/Evaluation of Solid Waste Management Strategies in Response to Future Electricity, Fuel & Transportation AU - Levis, J.W. AU - DeCarolis, J.F. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - CONF TI - Methane Enhancement by Anaerobic Composting of Food Waste and FOG AU - Yazdani, R. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - CONF TI - Systematic Evaluation of Industrial, Commercial, and Institutional Food Waste Management Strategies in the U.S AU - Levis, J.W. AU - Hodge, K.L. AU - DeCarolis, J.F. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - CONF TI - Understanding and Predicting Temperatures in Municipal Solid Waste Landfills AU - Hao, Z. AU - Sun, M. AU - Ducoste, J. AU - Luettich, S. AU - Castaldi, M. AU - Benson, C.H. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - SOUND TI - The Application of Life-Cycle Assessment to Solid Waste Management: Applications, Challenges and Modeling Techniques AU - Levis, J.W. AU - Barlaz, M.A. DA - 2016/// PY - 2016/// ER - TY - SOUND TI - Workshop on The Responsible Disposal of Flame Retarded Foams and Plastics AU - Barlaz, M DA - 2016/// PY - 2016/// ER - TY - RPRT TI - Integrated Solid Waste Management and Its Environmental Sustainability in a Carbon Constrained Environment AU - Levis, J.W. AU - DeCArolis, J.D. AU - Ranjithan, S.R. AU - Barlaz, M.A. A3 - Environmental Research and Education Foundation DA - 2016/5// PY - 2016/5// PB - Environmental Research and Education Foundation UR - https://erefdn.org/integrated-solid-waste-management-and-its-environmental-sustainability-in-a-carbon-constrained-environment/ ER - TY - CONF TI - Modernizing Methane Generation Models and Characterizing the Uncertainty from Select U.S. Landfills AU - Sun, W. AU - Wang, X. AU - DeCarolis, J.F. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2016/// CY - Indian Wells, CA DA - 2016/// PY - 2016/1/31/ ER - TY - SOUND TI - Climate Variability and its Impacts over the Southeast AU - Arumugam, S. DA - 2016/2/8/ PY - 2016/2/8/ ER - TY - SOUND TI - Water and ecological sustainability under near-term climate change AU - Arumugam, S. DA - 2016/3/10/ PY - 2016/3/10/ ER - TY - CONF TI - Predictive Classical and Hierarchical Bayesian Modeling for Yearly Irrigation Water Withdrawal over the Coterminous USA AU - Das, P. AU - Arumugam, S. T2 - World Environmental and Water Resources Congress (EWRI) C2 - 2016/5/22/ CY - West Palm Beach, FL DA - 2016/5/22/ PY - 2016/5/22/ ER - TY - CONF TI - Developing Categorical Streamflow Forecasts from Climate Forecasts Using Probabilistic Downscaling Methods AU - Mazrooei, A. AU - Arumugam, S. T2 - World Environmental and Water Resources Congress (EWRI) C2 - 2016/5/22/ CY - West Palm Beach, FL DA - 2016/5/22/ PY - 2016/5/22/ ER - TY - CONF TI - Multivariate Bias Correction Procedures for Improving Water Quality Predictions using Mechanistic Models AU - Libera, D. AU - Arumugam, S. T2 - World Environmental and Water Resources Congress (EWRI) C2 - 2016/5/22/ CY - West Palm Beach, FL DA - 2016/5/22/ PY - 2016/5/22/ ER - TY - CONF TI - Synthesis of US Public Water Supply: Spatio-temporal Patterns and Socio-Economic Controls 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 - 2016/12/12/ CY - San Francisco, CA DA - 2016/12/12/ PY - 2016/12/12/ ER - TY - CONF TI - Understanding the Effects of Groundwater Pumping on Streamflow: Human-Feedback Analysis on Downstream Impacts and Relevance to Reservoir Management AU - Seo, S.B. AU - Mahinthakumar, G. AU - Arumugam, S. AU - Kumar, M. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2016/5/22/ CY - West Palm Beach, Florida DA - 2016/5/22/ PY - 2016/5/22/ PB - EWRI, West Palm Beach ER - TY - CONF TI - Importance of Preserving Cross-correlation in developing Statistically Downscaled Climate Forcings AU - Bhowmik, R.D. AU - Arumugam, S. T2 - World Environmental & Water Resources Congress (EWRI) C2 - 2016/5/22/ CY - West Palm Beach, FL DA - 2016/5/22/ PY - 2016/5/22/ PB - EWRI, West Palm Beach ER - TY - CONF TI - Utilizing Climate Forecasts for Improving Water and Power Systems Coordination AU - Arumugam, S. AU - Quieroz, A. AU - Patskoski, J. AU - Mahinthakumar, G. AU - DeCarolis, J. T2 - American Geophysical Union Fall meeting C2 - 2016/12/12/ CY - San Francisco, CA DA - 2016/12/12/ PY - 2016/12/12/ ER - TY - CONF TI - Relationship between On-Site Planning Efforts and Work Plan Reliability AU - Abbasian-Hosseini, S. Alireza AU - Howell, Gregory AU - Liu, Min T2 - Construction Research Congress 2016 AB - Adequate planning is essential to successfully deliver a project. Construction site managers’ “planning” efforts include various levels: (1) identifying the sequence and timing of activities; (2) scheduling and organizing the wherewithal to perform the job; (3) planning with other project teams to coordinate for shared resources and/or interaction; and (4) designing the production system. Although there are several studies on construction project planning and its outcomes, the research pertaining to the effect of the on-site planning during construction on the performance is very limited. This research, via a questionnaire-based survey, identifies the relationship between the site manager’s effort on the 2nd and 3rd levels of planning and the work plan reliability (WPR), measured by the plan percent complete (PPC). The survey was distributed to site managers of general contractors and subcontractors in North Carolina, US. Eighty three useable survey responses were collected and classified based on management level, type of work, and project characteristics. Correlation analysis results show that there is a significant correlation between the efforts at the 3rd level of planning and the PPC average for the subcontractors. Results also show that the PPC variation decreases when more efforts are devoted on the 3rd level of planning. C2 - 2016/5/24/ CY - San Juan, Puerto Rico DA - 2016/5/24/ PY - 2016/5/31/ DO - 10.1061/9780784479827.212 PB - American Society of Civil Engineers SN - 9780784479827 UR - http://dx.doi.org/10.1061/9780784479827.212 ER - TY - JOUR TI - Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer AU - Xu, Zhida AU - Jiang, Jing AU - Wang, Xinhao AU - Han, Kevin AU - Ameen, Abid AU - Khan, Ibrahim AU - Chang, Te-Wei AU - Liu, Gang Logan T2 - Nanoscale AB - We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 10(8) and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU(-1). The SERS EF of FlexBrite in the wet state was found to be 4.81 × 10(8), 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays. DA - 2016/// PY - 2016/// DO - 10.1039/C5NR08357E VL - 8 IS - 11 SP - 6162-6172 J2 - Nanoscale LA - en OP - SN - 2040-3364 2040-3372 UR - http://dx.doi.org/10.1039/C5NR08357E DB - Crossref ER - TY - JOUR TI - Bus service quality prediction and attribute ranking: a neural network approach AU - Islam, Md Rokibul AU - Hadiuzzaman, Md AU - Banik, Rajib AU - Hasnat, Md Mehedi AU - Musabbir, Sarder Rafee AU - Hossain, Sanjana T2 - Public transport DA - 2016/// PY - 2016/// VL - 8 IS - 2 SP - 295-313 ER - TY - RPRT TI - Evaluation of Henry’s Law Constants and Freundlich Adsorption Constants for VOCs AU - Knappe, D.R.U. AU - Ingham, R.S. AU - Moreno-Barbosa, J. AU - Sun, M. AU - Summers, R.S. AU - Dougherty, T. A3 - Water Research Foundation DA - 2016/// PY - 2016/// M1 - 4462 M3 - Executive Summary PB - Water Research Foundation SN - 4462 ER - TY - JOUR TI - Evaluation of asphalt mixture laboratory long-term ageing methods for performance testing and prediction AU - Elwardany, Michael D. AU - Yousefi Rad, Farhad AU - Castorena, Cassie AU - Kim, Y. Richard T2 - Road Materials and Pavement Design AB - Ageing has long been recognised as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Ageing causes the material to stiffen and embrittle, which leads to a high potential for cracking. Although a significant amount of effort has been placed on understanding the ageing process of asphalt binder, less effort has been put forth to develop laboratory ageing procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term ageing for performance testing and prediction is required in order to integrate the effects of long-term ageing in pavement prediction models and other mechanistic design and analysis methods. In this study, oven ageing and pressure ageing vessel ageing are applied to both loose mix and compacted specimens in order to evaluate and select an ageing method to simulate long-term ageing for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the ageing methods. The results demonstrate that loose mix ageing in an oven is the most promising ageing method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost. DA - 2016/12/22/ PY - 2016/12/22/ DO - 10.1080/14680629.2016.1266740 VL - 18 IS - sup1 SP - 28-61 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2016.1266740 DB - Crossref KW - long-term ageing KW - ageing index properties KW - loose mix ageing ER - TY - JOUR TI - Modeling vehicle car-following behavior in congested traffic conditions based on different vehicle combinations AU - Kong, Dewen AU - List, George F. AU - Guo, Xiucheng AU - Wu, Dingxin T2 - Transportation Letters AB - This paper develops an improved cellular automaton model in congested traffic conditions that differentiates vehicle combinations to consider both vehicle physical performance and driving behavior difference in car-following behavior. Car-following is divided into four groups by the lead and lag vehicle type. The vehicle behavior, including steady space gap, acceleration, and behavior choice, was studied to find out the diversity of car-following behavior in different vehicle combinations. The results show that vehicles in different vehicle combinations have different car-following behaviors. In the proposed model, each vehicle combination has its particular update rules and parameters. The model was evaluated by comparison with the existing car-following models at the microscopic and macroscopic level and the stability was also analyzed. The results show that the improved cellular automata model has a satisfactory performance. DA - 2016/12/15/ PY - 2016/12/15/ DO - 10.1080/19427867.2016.1262979 VL - 10 IS - 5 SP - 280-293 J2 - Transportation Letters LA - en OP - SN - 1942-7867 1942-7875 UR - http://dx.doi.org/10.1080/19427867.2016.1262979 DB - Crossref KW - Car-following behavior KW - vehicle combination KW - vehicle interaction KW - cellular automata KW - freeway traffic flow KW - congested traffic condition ER - TY - CONF TI - Proposed Data-Driven Performance Measures for Comparing and Ranking Traffic Bottlenecks AU - Hale, D. AU - Hajbabaie, A. AU - Ma, J. AU - Hu, J. AU - Park, H. AU - Bared, J. AB - To justify investments towards improved traffic operations, engineers and policy-makers need scientific and accurate methods of congestion measurement. However, status-quo methods are limited and/or outdated. Peak-hour analyses are becoming outdated as a sole source of traffic assessment, because they fail to account for changing conditions throughout the year. There has been a movement towards “reliability” modeling, which attempts to capture these annual effects. But due to significant input data and calibration requirements, the reliability models suffer from practicality issues. Next, there have been recent improvements in data-driven ITS technologies, which identify congestion in real time. However, there is room for improvement in the robustness of performance measures derived from these technologies. Finally, some engineers have compared and ranked congested locations (i.e., bottlenecks) on the basis of experience and judgment. Despite their cost-effectiveness, judgment-based qualitative assessments will lack credibility unless backed by quantitative results. In a recent Federal Highway Administration study, congestion measurement was a primary area of emphasis. This paper discusses project-specific software development, which produced new and innovative performance measures for congestion measurement. It will present concepts and evidence to imply superiority of the proposed new measures. This paper is intended to serve as a preview of a future full journal paper; which will rank ten or more real-world bottlenecks according to new and old performance measures, to demonstrate impacts of the new measures. It is hoped that the new performance measures will be adopted by states and/or commercial products, for a new level of robustness in congestion measurement. C2 - 2016/// C3 - Transportation Research Procedia DA - 2016/// DO - 10.1016/j.trpro.2016.06.041 VL - 15 SP - 483-494 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84999816139&partnerID=MN8TOARS KW - performance measures KW - traffic bottlenecks KW - INRIX KW - reliability ER - TY - JOUR TI - Exploring shoreface dynamics and a mechanistic explanation for a morphodynamic depth of closure AU - Ortiz, Alejandra C. AU - Ashton, Andrew D. T2 - Journal of Geophysical Research: Earth Surface AB - Abstract Using energetics‐based formulations for wave‐driven sediment transport, we develop a robust methodology for estimating the morphodynamic evolution of a cross‐shore sandy coastal profile. In our approach, wave‐driven cross‐shore sediment flux depends on three components: two onshore‐directed terms (wave asymmetry and wave streaming) and an offshore‐directed slope term. In contrast with previous work, which applies shallow water wave assumptions across the transitional zone of the lower shoreface, we use linear Airy wave theory. The cross‐shore sediment transport formulation defines a dynamic equilibrium profile and, by perturbing about this steady state profile, we present an advection‐diffusion formula for profile evolution. Morphodynamic Péclet analysis suggests that the shoreface is diffusionally dominated. Using this depth‐dependent characteristic diffusivity timescale, we distinguish a morphodynamic depth of closure for a given time envelope. Even though wave‐driven sediment transport can (and will) occur at depths deeper than this morphodynamic closure depth, the rate of morphologic bed changes in response to shoreline change becomes asymptotically slow. Linear wave theory suggests a shallower shoreface depth of closure and much sharper break in processes than shallow water wave assumptions. Analyzing hindcasted wave data using a weighted frequency‐magnitude approach, we determine representative wave conditions for selected sites along the U.S. coastline. Computed equilibrium profiles and depths of closure demonstrate reasonable similarities, except where inheritance is strong. The methodology espoused in this paper can be used to better understand the morphodynamics at the lower shoreface transition with relative ease across a variety of sites and with varied sediment transport equations. DA - 2016/2// PY - 2016/2// DO - 10.1002/2015JF003699 VL - 121 IS - 2 SP - 442-464 J2 - J. Geophys. Res. Earth Surf. LA - en OP - SN - 2169-9003 UR - http://dx.doi.org/10.1002/2015JF003699 DB - Crossref KW - sediment transport KW - morphodynamic evolution KW - wave base ER - TY - JOUR TI - Correction to Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis AU - Siegert, Michael AU - Yates, Matthew D. AU - Call, Douglas F. AU - Zhu, Xiuping AU - Spormann, Alfred AU - Logan, Bruce E. T2 - ACS Sustainable Chemistry & Engineering AB - ADVERTISEMENT RETURN TO ISSUEPREVCorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to Comparison of Nonprecious Metal Cathode Materials for Methane Production by ElectromethanogenesisMichael Siegert, Matthew D. Yates, Douglas F. Call, Xiuping Zhu, Alfred Spormann, and Bruce E. Logan*Cite this: ACS Sustainable Chem. Eng. 2016, 4, 9, 5088Publication Date (Web):August 18, 2016Publication History Received27 July 2016Published online18 August 2016Published inissue 6 September 2016https://doi.org/10.1021/acssuschemeng.6b01763Copyright © 2016 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views570Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (201 KB) Get e-AlertsSUBJECTS:Anode materials,Carbon,Electrodes,Materials,Metals Get e-Alerts DA - 2016/8/18/ PY - 2016/8/18/ DO - 10.1021/ACSSUSCHEMENG.6B01763 VL - 4 IS - 9 SP - 5088-5088 J2 - ACS Sustainable Chem. Eng. LA - en OP - SN - 2168-0485 2168-0485 UR - http://dx.doi.org/10.1021/ACSSUSCHEMENG.6B01763 DB - Crossref ER - TY - CONF TI - Permeability Reduction Due to Microbial Induced Calcite Precipitation in Sand AU - Zamani, Atefeh AU - Montoya, Brina M. T2 - Geo-Chicago 2016 AB - Fine sands have shown that they are susceptible to liquefaction. There are many soil improvement methods that are effective in improving the shear strength and stiffness of fine sand but they often have limitations due to the soil characteristics, such as permeability. Microbial induced calcite precipitation (MICP) has been shown to be a natural and effective liquefaction mitigation method for clean fine sands. Although this method is effective, there may be limitations in implementing MICP in situ. In this study, the permeability reduction from MICP is investigated to understand its implications for field implementation of MICP treatments. Fine sand specimens have been treated to different cementation levels, estimated using nondestructive shear wave velocity measurements. Permeability of treated samples is measured using a constant head permeameter. Utilizing the permeability results of the treated specimens, numerical simulations of the MICP treatments are evaluated by creating a constant head difference between an injection and extraction well and observing the water velocity changes within the domain. C2 - 2016/8/8/ C3 - Geo-Chicago 2016 DA - 2016/8/8/ DO - 10.1061/9780784480120.011 PB - American Society of Civil Engineers SN - 9780784480120 UR - http://dx.doi.org/10.1061/9780784480120.011 DB - Crossref ER - TY - CONF TI - Particulate Simulations of Triaxial Tests on Bio-Cemented Sand Using a New Cementation Model AU - Khoubani, A. AU - Evans, T. M. AU - Montoya, B. M. T2 - Geo-Chicago 2016 AB - Bio-cementation is a promising method for the natural improvement of potentially liquefiable soil deposits (e.g., loose saturated sands). In the improvement process a bacterium that can be found naturally in soil deposits is fed urea. The bacterium consumes and breaks down the urea to form ammonium and carbonate. In the presence of calcium, calcium carbonate will precipitate at particle contacts and act as a cementitious agent to solidify the deposit. Moreover, experimental tests show that bio-cemented sand exhibits more ductile behavior than chemically cemented sand. This is a desirable response from an engineering point of view, since brittle failure is often catastrophic and occurs without warning. The scope of this study is to investigate the response of bio-cemented sand using the discrete element method (DEM). This numerical method is capable of simulating behavior of granular materials based upon the basic particle-scale physics of the system of interest. A new cementation model is proposed that replicates the presence of cement between soil particles. This bond is able to capture the progressive contact dissolution between two soil particles and associated nonlinear response. Triaxial samples were built and the aforementioned bond was applied to the contact points within the assembly. Samples with and without cementation are sheared and their stress-strain responses compared in terms of soil strength and stiffness. The effects of several bonding parameters are investigated and the relative contributions of multiple physical mechanisms to system response are considered. C2 - 2016/8/8/ C3 - Geo-Chicago 2016 DA - 2016/8/8/ DO - 10.1061/9780784480120.010 PB - American Society of Civil Engineers SN - 9780784480120 UR - http://dx.doi.org/10.1061/9780784480120.010 DB - Crossref ER - TY - CONF TI - Erosion Reduction of Coastal Sands Using Microbial Induced Calcite Precipitation AU - Shanahan, Casey AU - Montoya, Brina M. T2 - Geo-Chicago 2016 AB - Effects of sea level rising and increasing storm severity create a more damage prone environment for coastal regions. Large storm surges can be devastating to coastal infrastructure, damaging roads, utilities, structures, and endangering the lives of local residents. Coastal sand dunes act as a primary defense to wave action, making their resiliency of the utmost importance. Microbial induced calcite precipitation (MICP) offers a potentially sustainable alternative to seawall and revetment type solutions which destroy entire ecosystems in order to protect cities or other areas of interest. Bio-cementation has been shown to improve the strength and stiffness of unsaturated sand. The study presented herein displays the behavior of MICP treated coastal sand when subjected to wave action. Two wave tank tests were conducted to assess the change in measured erosion for untreated sand and moderately cemented sand. To quantitatively measure the reduction in erosion, 3-D morphology was observed using a laser scanner before and after subjecting the sand to wave action. Acoustic wave gauges were used to monitor the input wave functions and the breaking waves on the soil surface. Further understanding of the erosion reduction potential of MICP treated sand increases the feasibility of in-situ application to coastal sand dunes. C2 - 2016/8/8/ C3 - Geo-Chicago 2016 DA - 2016/8/8/ DO - 10.1061/9780784480120.006 PB - American Society of Civil Engineers SN - 9780784480120 UR - http://dx.doi.org/10.1061/9780784480120.006 DB - Crossref ER - TY - JOUR TI - Determination of Sources of Organic Matter in Solid Waste by Analysis of Phenolic Copper Oxide Oxidation Products of Lignin AU - De la Cruz, Florentino B. AU - Osborne, Jason AU - Barlaz, Morton A. T2 - Journal of Environmental Engineering AB - The decomposition behavior of lignocellulosic materials is related to the taxonomic classes of the parent plant tissues. Thus, methods to characterize the composition of mixtures of lignocellulosic materials such as municipal solid waste (MSW) according to different taxonomic classes of plants are useful. The copper oxide (CuO) oxidation products of lignin provide molecular markers that allow for characterization of the initial plants. The objective of this study was to determine if the chemical composition of the monomers present after CuO oxidation can be used to infer information on the content of woody angiosperms (hardwood—HW), non-woody angiosperms (leaves and grasses—LG), woody gymnosperms (softwood—SW), and non-woody gymnosperms (needles—GN). Results showed that the composition of HW and SW in synthetic mixtures can be estimated from CuO oxidation products of lignin within an error of ±60% of the expected values. The high uncertainty in the estimate of composition in synthetic mixtures can be attributed to the fact that the components selected for the synthetic mixtures had different CuO oxidation products compared to the average which was used in developing the mixing model. Application of the mixing model to estimate the composition of samples from a Kentucky (KY) landfill showed that the majority of the samples are from HW and SW with little to no non-woody tissues (LG, GN). However, the mixing model is not sufficiently precise to infer more detailed information on MSW composition. DA - 2016/2// PY - 2016/2// DO - 10.1061/(ASCE)EE.1943-7870.0001038 VL - 142 IS - 2 SP - 04015076 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001038 DB - Crossref KW - CuO KW - Lignin KW - Angiosperms KW - Gymnosperms KW - Municipal solid waste (MSW) KW - Solid waste ER - TY - JOUR TI - A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes AU - Sun, Mei AU - Sun, Wenjie AU - Barlaz, Morton A. T2 - Science of The Total Environment AB - Large volumes of sulfur-containing wastes enter municipal solid waste landfills each year. Under the anaerobic conditions that prevail in landfills, oxidized forms of sulfur, primarily sulfate, are converted to sulfide. Hydrogen sulfide (H2S) is corrosive to landfill gas collection and treatment systems, and its presence in landfill gas often necessitates the installation of expensive removal systems. For landfill operators to understand the cost of managing sulfur-containing wastes, an estimate of the H2S production potential is needed. The objective of this study was to develop and demonstrate a biochemical sulfide potential (BSP) test to measure the amount of H2S produced by different types of sulfur-containing wastes in a relatively fast (30days) and inexpensive (125mL serum bottles) batch assay. This study confirmed the toxic effect of H2S on both sulfate reduction and methane production in batch systems, and demonstrated that removing accumulated H2S by base adsorption was effective for mitigating inhibition. H2S production potentials of coal combustion fly ash, flue gas desulfurization residual, municipal solid waste combustion ash, and construction and demolition waste were determined in BSP assays. After 30days of incubation, most of the sulfate in the wastes was converted to gaseous or aqueous phase sulfide, with BSPs ranging from 0.8 to 58.8mLH2S/g waste, depending on the chemical composition of the samples. Selected samples contained solid phase sulfide which contributed to the measured H2S yield. A 60day incubation in selected samples resulted in 39-86% additional sulfide production. H2S production measured in BSP assays was compared with that measured in simulated landfill reactors and that calculated from chemical analyses. H2S production in BSP assays and in reactors was lower than the stoichiometric values calculated from chemical composition for all wastes tested, demonstrating the importance of assays to estimate the microbial sulfide production potential of sulfur-containing wastes. DA - 2016/5// PY - 2016/5// DO - 10.1016/J.SCITOTENV.2016.01.161 VL - 551-552 SP - 23-31 J2 - Science of The Total Environment LA - en OP - SN - 0048-9697 UR - http://dx.doi.org/10.1016/J.SCITOTENV.2016.01.161 DB - Crossref KW - Hydrogen sulfide KW - Landfill KW - Construction and demolition waste KW - Flue gas desulfurization ash KW - Municipal solid waste KW - Coal combustion fly ash ER - TY - JOUR TI - Chemical composition and methane potential of commercial food wastes AU - Lopez, Victoria M. AU - De la Cruz, Florentino B. AU - Barlaz, Morton A. T2 - Waste Management AB - There is increasing interest in anaerobic digestion in the U.S. However, there is little information on the characterization of commercial food waste sources as well as the effect of waste particle size on methane yield. The objective of this research was to characterize four commercial food waste sources: (1) university dining hall waste, (2) waste resulting from prepared foods and leftover produce at a grocery store, (3) food waste from a hotel and convention center, and (4) food preparation waste from a restaurant. Each sample was tested in triplicate 8 L batch anaerobic digesters after shredding and after shredding plus grinding. Average methane yields for the university dining, grocery store, hotel, and restaurant wastes were 363, 427, 492, and 403 mL/dry g, respectively. Starch exhibited the most complete consumption and particle size did not significantly affect methane yields for any of the tested substrates. Lipids represented 59–70% of the methane potential of the fresh substrates. DA - 2016/10// PY - 2016/10// DO - 10.1016/j.wasman.2016.07.024 VL - 56 SP - 477-490 J2 - Waste Management LA - en OP - SN - 0956-053X UR - http://dx.doi.org/10.1016/j.wasman.2016.07.024 DB - Crossref KW - Food waste KW - Anaerobic digestion KW - Biochemical methane potential ER - TY - JOUR TI - A continuum damage model for asphalt cement and asphalt mastic fatigue AU - Underwood, B. Shane T2 - International Journal of Fatigue AB - An analytical model is developed for the mechanical degradation of asphalt cement and mastic under repeated loading. The model is derived by applying the strain decomposition principle to consider linear viscoelastic, nonlinear viscoelastic, and damage mechanisms. The experimental processes to isolate the behaviors and the analytical functions used to model each are described. It is found that the Schapery type damage approach is capable of modeling the fatigue process of these materials once appropriate consideration is taken for their nonlinear viscoelastic responses. Fatigue in asphalt mastics is also found to occur due to physical damage occurring in the asphalt cement. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.ijfatigue.2015.08.020 VL - 82 SP - 387-401 J2 - International Journal of Fatigue LA - en OP - SN - 0142-1123 UR - http://dx.doi.org/10.1016/j.ijfatigue.2015.08.020 DB - Crossref KW - Continuum damage KW - Nonlinear viscoelastic KW - Asphalt cement KW - Asphalt mastic KW - Fatigue ER - TY - JOUR TI - Influence of High-Strength Bars on Shear Response of Containment Walls AU - Proestos, Giorgio AU - Bae, G.-M. AU - Cho, J.-Y. AU - Bentz, E.C. AU - Collins, M.P. T2 - ACI Structural Journal AB - First Name is required invalid characters Last Name is required invalid characters Email Address is required Invalid Email Address Invalid Email Address DA - 2016/9// PY - 2016/9// DO - 10.14359/51688750 VL - 113 IS - 5 SP - 917-927 OP - SN - 0889-3241 UR - http://dx.doi.org/10.14359/51688750 DB - Crossref KW - axial stress KW - compression KW - high-strength steel KW - nuclear containment KW - shear KW - shell elements KW - tension KW - wall ER - TY - CONF TI - The design and analysis of reinforced concrete shell elements subjected to in-plane and out-of-plane shear stresses AU - Proestos, G.T. AU - Bentz, E.C. AU - Collins, M.P. C2 - 2016/// C3 - Proceedings of the 11th fib International PhD Symposium in Civil Engineering, FIB 2016 DA - 2016/// SP - 695-702 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84991738344&partnerID=MN8TOARS ER - TY - CONF TI - Understanding engineering students' professional pathways: a longitudinal mixed-methods study AU - Brunhaver, Samantha AU - Matusovich, Holly M AU - Streveler, Ruth A AU - Sheppard, Sheri AU - Carrico, Cheryl AU - Harris, Angela T2 - American Society for Engineering Education C2 - 2016/// C3 - 123rd ASEE Annual Conference and Exposition DA - 2016/// ER - TY - JOUR TI - Occurrence of host-associated fecal markers on child hands, household soil, and drinking water in rural Bangladeshi households AU - Boehm, Alexandria B AU - Wang, Dan AU - Ercumen, Ayse AU - Shea, Meghan AU - Harris, Angela R AU - Shanks, Orin C AU - Kelty, Catherine AU - Ahmed, Alvee AU - Mahmud, Zahid Hayat AU - Arnold, Benjamin F AU - others T2 - Environmental Science & Technology Letters DA - 2016/// PY - 2016/// VL - 3 IS - 11 SP - 393-398 ER - TY - JOUR TI - Ruminants contribute fecal contamination to the urban household environment in Dhaka, Bangladesh AU - Harris, Angela R AU - Pickering, Amy J AU - Harris, Michael AU - Doza, Solaiman AU - Islam, M Sirajul AU - Unicomb, Leanne AU - Luby, Stephen AU - Davis, Jennifer AU - Boehm, Alexandria B T2 - Environmental science & technology DA - 2016/// PY - 2016/// VL - 50 IS - 9 SP - 4642-4649 ER - TY - CONF TI - Helping engineering students get jobs: Views from career services professionals AU - Carrico, Cheryl AU - Harris, Angela AU - Matusovich, Holly M AU - Brunhaver, Samantha AU - Streveler, Ruth A AU - Sheppard, Sheri T2 - American Society for Engineering Education C2 - 2016/// C3 - 123rd ASEE Annual Conference and Exposition DA - 2016/// ER - TY - JOUR TI - Biochar sorbents for sulfamethoxazole removal from surface water, stormwater, and wastewater effluent AU - Thompson, K.A. AU - Shimabuku, K.K. AU - Kearns, J.P. AU - Knappe, D.R.U. AU - Summers, R.S. T2 - Water Research AB - This study examined sorption of the human and veterinary antibiotic sulfamethoxazole (SMX) at environmentally relevant concentrations from laboratory clean water, surface water, stormwater, and wastewater effluent to wood and wastewater-sludge derived biochars produced under a wide range of conditions. SMX sorption by commercial powdered activated carbon (PAC) was also quantified as a benchmark. Wood-based biochar produced around 850 °C performed similarly to PAC. Biochar sorption capacity increased with surface area up to ∼400 m2/g. However, a further increase in surface area did not correspond to an increase in sorption capacity. Sorbent H:C ratios correlated with SMX uptake by PAC and wood-based biochars, but not for the sludge-based biochars. This is possibly due to an indirect influence of the high ash content in sludge-based biochars, as the isolated ash fraction exhibited negligible SMX sorption capacity. The presence of dissolved organic matter (DOM) in the natural and anthropogenic waters fouled most of the sorbents (i.e., decreased SMX uptake). The sludge-based biochars experienced less DOM fouling relative to wood-based biochar, particularly in the wastewater effluent. Biochar and PAC sorption kinetics were similar when examined over a contact time of four-hours, suggesting their performance ranking would be consistent at contact times typically utilized in water treatment systems. In the presence of DOM, SMX relative removal (C/C0) was independent of SMX initial concentration when the initial concentration was below 10 μg/L, thus permitting the relative removal results to be applied for different SMX initial concentrations typical of environmental and anthropogenically impacted waters. DA - 2016/6// PY - 2016/6// DO - 10.1016/j.watres.2016.03.049 VL - 50 SP - 11253–11262 UR - http://dx.doi.org/10.1016/j.watres.2016.03.049 KW - Powdered activated carbon KW - Trace organic contaminants KW - Sorption kinetics KW - Dissolved organic matter KW - Fouling KW - Fluorescence ER - TY - JOUR TI - Investigation of Aging in Hydrated Lime and Portland Cement Modified Asphalt Concrete at Multiple Length Scales AU - Gundla, Akshay AU - Medina, Jose AU - Gudipudi, Padmini AU - Stevens, Ryan AU - Salim, Ramadan AU - Zeiada, Waleed AU - Shane Underwood, B. T2 - Journal of Materials in Civil Engineering AB - The properties of asphalt concrete are the result of many interdependent physical and chemical mechanisms occurring across multiple length scales. Admixtures such as hydrated lime (HL) and portland cement (PC) are known to affect the behaviors of asphalt concrete at the macroscale, but their contribution at other scales and influences on overall performance of the material are not well understood. This paper presents the findings of a study that evaluates the potential for HL and PC for mitigating the effects of asphalt concrete aging with respect to modulus and fatigue resistance. The properties of interest were evaluated at multiple scales, which involved binder, mastic, and mixture testing. Rheological analyses of aged and non-aged control, HL modified, and PC modified mastics indicate that HL possesses greater potential to mitigate aging than PC. In mixture testing, the modulus results showed trends similar to that of mastics, in which the HL-modified samples were the stiffest and showed greater potential to mitigate aging. As expected, the relative increase in stiffness and relative potential to mitigate aging, averaged across temperatures, was found to be higher in mastics than the mixtures. The results from the uniaxial fatigue test show that HL mixtures possess higher fatigue resistance when aged, thus less negative effects from the oxidation process. Magnification of aging mitigation potential at the mastic scale, and its direct correlation to fatigue behavior, explains why multiple scale evaluations can be useful in evaluating the true benefits of the admixtures. DA - 2016/5// PY - 2016/5// DO - 10.1061/(ASCE)MT.1943-5533.0001501 VL - 28 IS - 5 SP - 04015205 J2 - J. Mater. Civ. Eng. LA - en OP - SN - 0899-1561 1943-5533 UR - http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0001501 DB - Crossref KW - Oxidation KW - Aging KW - Asphalt mastic KW - Fatigue KW - Continuum damage ER - TY - JOUR TI - Effect of Binder Modification on the Performance of an Ultra-Thin Overlay Pavement Preservation Strategy AU - Mogawer, Walaa S. AU - Austerman, Alexander J. AU - Underwood, Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The objective of this study was to determine whether asphalt rubber (AR) binders will provide similar or better performance compared with a polymer modified asphalt (PMA) binder when used in a high-performance, ultra-thin lift overlay pavement preservation strategy. Current specifications for these types of overlays normally require the use of a PMA binder, because it has the ability to make these overlays more elastic under traffic loading and is less sensitive to temperature fluctuations. However, several state agencies are looking into the feasibility of incorporating sustainable and environmentally friendly technologies, such as AR binders and warm mix asphalt (WMA) technologies, into their asphalt mixtures, including those used for high-performance, ultra-thin lift overlays. This study examined the effect of binder modification type (AR or PMA) and the influence of the use of WMA in high-performance, ultra-thin lift overlays. In general, the mixtures that were tested provided comparable rutting, moisture damage, and low-temperature cracking performance in the high-performance, ultra-thin lift overlay. However, the use of the AR binders indicated reduced performance compared with the PMA binder in mixture fatigue cracking via the beam fatigue test, and mixture reflective cracking in the overlay tester. The results from the beam fatigue test were not always supported by the fatigue life predictions from the simplified viscoelastic continuum damage model. The only detriment to mixture performance for mixtures incorporating WMA was a reduction in fatigue cracking performance when used with AR binders. DA - 2016/1// PY - 2016/1// DO - 10.3141/2550-01 VL - 2550 IS - 1 SP - 1-7 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2550-01 DB - Crossref ER - TY - JOUR TI - Development of a Test Protocol to Measure Uniaxial Fatigue Damage and Healing AU - Zeiada, Waleed Abdelaziz AU - Kaloush, Kamil E. AU - Underwood, B. Shane AU - Mamlouk, Michael T2 - Transportation Research Record: Journal of the Transportation Research Board AB - Various laboratory testing methods have been developed to characterize the fatigue response of asphalt concrete mixtures. These test methods attempt to simulate in-service conditions or formulate constitutive models. Experiments such as the four-point beam fatigue test have attempted to simulate in-service conditions. The prediction accuracy of such experiments depends on their effectiveness in simulating actual field conditions such as loading, support, stress state, and environment. Constitutive modeling experiments have aimed at measuring fundamental stress–strain relationships so that rigorous constitutive models can be formulated. The results from these experiments are used as input for field performance prediction algorithms. The uniaxial fatigue test is a promising method in this category because of the constant stress state across the specimen section. A few documents have focused on standard test methods for the uniaxial fatigue test; however, there are no AASHTO or ASTM protocols available that include the healing of asphalt concrete mixtures. The main objective of this study was to report on the development of a uniaxial fatigue test protocol that measures fatigue damage and healing of asphalt concrete mixtures. The documented work includes surrogate studies to identify appropriate sample fabrication procedures, gluing materials and procedures, alignment, machine compliance, type of strain wave shape, and strain-control mode of loading. It was found that the use of a gluing jig and 180-mm compaction height was essential to achieve successful mid-specimen failures. In addition, the sinusoidal strain wave shape and on-specimen strain-controlled mode of loading are appropriate test conditions for fatigue damage and healing characterization of asphalt concrete mixtures. DA - 2016/1// PY - 2016/1// DO - 10.3141/2576-02 VL - 2576 IS - 1 SP - 10-18 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2576-02 DB - Crossref ER - TY - JOUR TI - Identifying Indicators for Fatigue Cracking in Hot-Mix Asphalt Pavements Using Viscoelastic Continuum Damage Principles AU - Mensching, David J. AU - Rahbar-Rastegar, Reyhaneh AU - Underwood, B. Shane AU - Daniel, Jo Sias T2 - Transportation Research Record: Journal of the Transportation Research Board AB - A critical distress in asphalt concrete pavements is fatigue cracking, which results in decreased ride quality and fuel economy, and provides an avenue for water intrusion, which causes a pavement system to deteriorate rapidly. Given the poor state of the infrastructure network, changes are needed in the current mixture design process to promote innovation and alternative approaches to production. This study addressed this need by pursuing the following objectives: ( a) relate mixture stiffness, fatigue, and pavement system characteristics for performance-based mixture design; ( b) identify a simplified viscoelastic continuum damage (S-VECD) output parameter that most clearly distinguishes between poor and satisfactory performance when combined with dynamic modulus information; and ( c) evaluate the impact of recycled materials on performance indicators for fatigue cracking. The results show that a pavement structure selection process related to the S-VECD failure criterion produces better performance predictions than does a stiffness-based approach. Promising correlations with performance exist for the pseudostiffness at failure and storage modulus for an Interstate pavement structure, phase angle for a state highway surface and base course, and model term alpha for the same state highway base course. DA - 2016/1// PY - 2016/1// DO - 10.3141/2576-04 VL - 2576 IS - 1 SP - 28-39 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2576-04 DB - Crossref ER - TY - JOUR TI - Correlating field performance to laboratory dynamic modulus from indirect tension and torsion bar AU - Yang, Shu AU - Braham, Andrew AU - Underwood, Shane AU - Hanz, Andrew AU - Reinke, Gerald T2 - Road Materials and Pavement Design AB - Dynamic modulus has several useful functions in flexible pavements, including stress/strain characterisation, rutting and cracking characterisation, an input into several analytical and numerical models, and a primary input into Pavement ME Design. While the traditional dynamic modulus test is run in the uniaxial configuration, this is not possible for field cores. Therefore, the indirect tension dynamic modulus (IDT |E*|) and torsion bar shear modulus (torsion bar |G*|) have been developed. However, there has been limited research looking at analysing the data from field cores for these two geometries, comparing modulus data from the two geometries, examining in-service ageing of dynamic modulus, and quantifying pavement conditions using dynamic modulus. This research examines 10 field sections in Arkansas, comprising of 4 “good” performing sections, 2 “medium” performing sections, and 4 “poor” performing sections in an attempt to address these four questions. First, this research found that using AASHTO T342 and AASHTO R62 can lead to irrational coefficients but provide rational results. Second, while the IDT |E*| and torsion bar |G*| values were similar at high modulus values, the IDT |E*| values began to increase as the modulus decreased compared to the torsion bar |G*| values, increasing to over a decade of difference. Third, a noticeable difference was observed between the modulus values of the bottom surface layer and top surface layer, with the bottom surface layer showing higher modulus values in all cases. While the upper surface layer showed higher oxidation, other weathering effects such as moisture and traffic appear to have overwhelmed the oxidation effect and pavement deterioration has reduced the integrity of the mix. Finally, both the IDT |E*| and torsion bar |G*| were not able to quantify a noticeable difference between poor and medium performing sections, and medium and good performing sections, but were able to quantify a difference between the poor and good behaving sections. Overall, the IDT |E*| and torsion bar |G*| tests were able to produce consistent master curves, correlate to each other, identify differences between surface course lifts, and quantify differences in field performance. DA - 2016/12/28/ PY - 2016/12/28/ DO - 10.1080/14680629.2016.1267438 VL - 18 IS - sup1 SP - 104-127 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2016.1267438 DB - Crossref KW - dynamic modulus KW - field performance KW - IDT vertical bar E*vertical bar KW - torsion bar vertical bar G*vertical bar KW - ageing ER - TY - JOUR TI - Development of Modulus and Fatigue Test Protocol for Fine Aggregate Matrix for Axial Direction of Loading AU - Gudipudi, P. P. AU - Underwood, B. S. T2 - Journal of Testing and Evaluation AB - Abstract The testing of fine aggregate matrix (FAM) is rapidly gaining attention in the pavement research community because of its notable similarities with asphalt concrete (AC) and the increased testing efficiency that it affords. In most of the existing studies, FAM tests are used for characterization of relative material performance in the presence of phenomenon like moisture damage and healing. However, to better understand the fundamental properties of FAM and to establish the mechanistic connection between its properties and those of AC, proper fabrication and testing protocols need to be established. The focus of this research is to develop such standard testing protocols for both dynamic modulus and uniaxial fatigue testing. In the current effort, two FAM materials are prepared with the same gradation but two different asphalt cements (PG 64-22 and PG 76-16). Pilot studies to support the development of sample fabrication protocols are explained. Both FAM materials are tested for modulus and uniaxial fatigue, and during testing both on-specimen and machine actuator displacement are recorded. Material parameters were separately calculated using these two deformation measurements and compared to uncover the errors resulting from machine-based measurements of FAM. The percentage error in measuring dynamic modulus of FAM specimens using actuator strain ranged from 5 % to 79 %. After correcting actuator strain with a constant machine compliance factor, the percentage error changed to 10 %–32 %, which is still high. In addition, variation in time dependency and fatigue damage characterization was observed using the corrected actuator data to on-specimen data. To overcome all of the above issues and measure reliable test data for FAM, it is concluded that protocols must include measurement of on-specimen deformation. DA - 2016/3/21/ PY - 2016/3/21/ DO - 10.1520/JTE20150295 VL - 45 IS - 2 SP - 20150295 J2 - J. Test. Eval. LA - en OP - SN - 0090-3973 UR - http://dx.doi.org/10.1520/JTE20150295 DB - Crossref KW - asphalt concrete KW - fine aggregatematrix KW - axial testing KW - dynamicmodulus KW - uniaxial fatigue KW - machine compliance factor ER - TY - JOUR TI - Visual monitoring of civil infrastructure systems via camera-equipped Unmanned Aerial Vehicles (UAVs): a review of related works AU - Ham, Youngjib AU - Han, Kevin K. AU - Lin, Jacob J AU - Golparvar-Fard, Mani T2 - Visualization in Engineering AB - Abstract Over the past few years, the application of camera-equipped Unmanned Aerial Vehicles (UAVs) for visually monitoring construction and operation of buildings, bridges, and other types of civil infrastructure systems has exponentially grown. These platforms can frequently survey construction sites, monitor work-in-progress, create documents for safety, and inspect existing structures, particularly for hard-to-reach areas. The purpose of this paper is to provide a concise review of the most recent methods that streamline collection, analysis, visualization, and communication of the visual data captured from these platforms, with and without using Building Information Models (BIM) as a priori information. Specifically, the most relevant works from Civil Engineering, Computer Vision, and Robotics communities are presented and compared in terms of their potential to lead to automatic construction monitoring and civil infrastructure condition assessment. DA - 2016/1/6/ PY - 2016/1/6/ DO - 10.1186/s40327-015-0029-z VL - 4 IS - 1 J2 - Vis. in Eng. LA - en OP - SN - 2213-7459 UR - http://dx.doi.org/10.1186/s40327-015-0029-z DB - Crossref ER - TY - JOUR TI - Lifecycle Process Model for Municipal Solid Waste Collection AU - Jaunich, Megan K. AU - Levis, James W. AU - Barlaz, Morton A. AU - DeCarolis, Joseph F. T2 - Journal of Environmental Engineering AB - A process model was developed using a lifecycle approach to estimate the cost and energy use associated with municipal solid waste collection, which is the most fuel-intensive and often the most costly aspect of solid waste management. The model divides collection service areas into single-family residential, multi-family residential, and commercial sectors with sector-specific, user-defined characteristics, including population, waste generation, and waste composition. Waste is collected by a set of processes (e.g., residual waste, recyclables collection) defined by costs, collection activity parameters, and energy use. The model overpredicted fuel use by ~25% compared with data obtained from actual single-family residential collection routes and their average fuel efficiencies, but was within 10% when modal fuel efficiencies (e.g., driving, idling) were considered. Adding recyclables or yard waste collection to a mixed waste collection program increased fuel consumption by approximately 75% per metric ton (Mg) and doubled cost, whereas adding both services more than doubled fuel use and tripled cost. Increasing recyclables and residual collection frequency from biweekly to weekly resulted in a predicted 53% increase in fuel consumption and 39% increase in cost. Sensitivity analysis illustrated the relative impact of changing individual parameters (e.g., route to disposal facility distance, average time at each stop) and highlighted the need for a mechanistic model that is responsive to variations in input values. DA - 2016/8// PY - 2016/8// DO - 10.1061/(asce)ee.1943-7870.0001065 VL - 142 IS - 8 SP - 04016037 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(asce)ee.1943-7870.0001065 DB - Crossref ER - TY - JOUR TI - Comparative Assessment of Models and Methods To Calculate Grid Electricity Emissions AU - Ryan, Nicole A. AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. T2 - Environmental Science & Technology AB - Due to the complexity of power systems, tracking emissions attributable to a specific electrical load is a daunting challenge but essential for many environmental impact studies. Currently, no consensus exists on appropriate methods for quantifying emissions from particular electricity loads. This paper reviews a wide range of the existing methods, detailing their functionality, tractability, and appropriate use. We identified and reviewed 32 methods and models and classified them into two distinct categories: empirical data and relationship models and power system optimization models. To illustrate the impact of method selection, we calculate the CO2 combustion emissions factors associated with electric-vehicle charging using 10 methods at nine charging station locations around the United States. Across the methods, we found an up to 68% difference from the mean CO2 emissions factor for a given charging site among both marginal and average emissions factors and up to a 63% difference from the average across average emissions factors. Our results underscore the importance of method selection and the need for a consensus on approaches appropriate for particular loads and research questions being addressed in order to achieve results that are more consistent across studies and allow for soundly supported policy decisions. The paper addresses this issue by offering a set of recommendations for determining an appropriate model type on the basis of the load characteristics and study objectives. DA - 2016/8/8/ PY - 2016/8/8/ DO - 10.1021/acs.est.5b05216 VL - 50 IS - 17 SP - 8937-8953 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.5b05216 DB - Crossref ER - TY - JOUR TI - Emissions impacts of using energy storage for power system reserves AU - Lin, Yashen AU - Johnson, Jeremiah X. AU - Mathieu, Johanna L. T2 - Applied Energy AB - Energy storage devices, such as batteries and flywheels, are promising options for providing operating reserves due to their fast response and low emissions during operation. However, because of the complex nature of power systems, adding energy storage-based reserves to the power system may not necessarily benefit the environment. In this paper, we analyze these impacts in a test system and identify important drivers that affect the environmental outcomes. Dispatch results are obtained by solving an optimal power flow (OPF) problem and are used to determine emissions. We find that the impacts of adding energy storage are highly case-dependent. In systems with high renewable penetration levels and significant renewable curtailment, adding energy storage reduces emissions; in other systems, the impacts on emissions could be positive, neutral, or negative. The analyses presented in this paper show that policies to procure energy storage as a means to reduce emissions may actually lead to increased system-wide emissions if current dispatch algorithms are used. We also explore the impacts of modifying the dispatch algorithm to ensure system emissions with energy storage are no worse than system emissions without energy storage. DA - 2016/4// PY - 2016/4// DO - 10.1016/j.apenergy.2016.01.061 VL - 168 SP - 444-456 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/j.apenergy.2016.01.061 DB - Crossref KW - Energy storage KW - Operating reserves KW - Emissions KW - Optimal power flow ER - TY - JOUR TI - Impact of inverter loading ratio on solar photovoltaic system performance AU - Good, Jeremy AU - Johnson, Jeremiah X. T2 - Applied Energy AB - Due to decreasing solar module prices, some solar developers are increasing their projects’ inverter loading ratio (ILR), defined as the ratio of DC module capacity to AC inverter capacity. In this study, we examine the operational impacts of this trend. Using minute-level solar data, we examine the relationship between inverter induced clipping losses and AC generation. We find minimal clipping losses at an ILR of 1.25; at an ILR of 2.0, we observe that 16% of potential annual generation is lost. Minute-level data prove to be essential in determining the generation lost to clipping, as hourly data mask key clipping and ramping events. Higher ILRs lead to a greater frequency of time spent at maximum generation, but also a greater frequency and magnitude of large solar ramping events. Module degradation can attenuate the impacts of inverter clipping over time. We observe that the effective degradation rate (net of any changes to inverter clipping losses) can be as little as half the actual degradation rate for projects with high ILRs. The diurnal and seasonal trends in clipping correspond with solar insolation patterns, with the highest clipping occurring around noon. For fixed tilt installations with tilt angles at latitude, we observe the highest clipping near the autumnal and vernal equinoxes. Increasing the tilt angle leads to more winter clipping, while lower tilt angles shifts the clipping to summer months. Shifting from fixed tilt to north–south single axis tracking increases the generation lost to clipping significantly. At an ILR of 1.25, annual clipping approximately doubles to 1% compared to fixed tilt at latitude, while clipping under an ILR of 2.0 increases to 22%, compared to 16% for the fixed configuration. As expected, more clipping occurs during the hours preceding and following noon when using single axis tracking. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.apenergy.2016.05.134 VL - 177 SP - 475-486 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/j.apenergy.2016.05.134 DB - Crossref KW - Inverter loading ratio KW - DC/AC ratio KW - Solar KW - Clipping KW - Ramp rate KW - Module degradation ER - TY - JOUR TI - Emissions reduction benefits of siting an offshore wind farm: A temporal and spatial analysis of Lake Michigan AU - Chiang, Amy C. AU - Moore, Michael R. AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. T2 - Ecological Economics AB - Siting decisions of offshore wind farms influence the magnitude of emissions reduction benefits. This paper calculates electricity generation and emissions reduction of CO2, NOx, and SO2, and values these reductions to determine the impact of the siting location for a 300 MW offshore wind farm in Lake Michigan. The most important patterns for emissions reduction were the monthly trends, where January, March, and December consistently had the highest electricity generation and emissions reduction benefits. Summer months such as July and August had the lowest emissions reduction benefits. The intra-day trends showed higher emissions reduction benefits during off-peak hours, due to a higher likelihood of coal units being the marginal generator. These diurnal differences were smaller in magnitude than the seasonal differences. Two benefit valuation scenarios were analyzed for a 20-year time period, one using marginal damages of pollution and another using market prices for pollution allowances. The first scenario resulted in emissions reduction benefits ranging from $1827/kW to $2690/kW ($2508/kW averaged) throughout the Lake Michigan region for the 20-year period (applying a 3% discount rate). This equates to approximately $33/MWh in all lake locations since the emissions reduction benefits are primarily a function of electricity generation. The market price scenario resulted in a much lower range of $820/kW to $1060/kW ($987/kW average or 39% of the pollution damage costs). In scenario 1, the major component of emissions reduction benefits was CO2 reduction (86% of benefits), and 83% of these CO2 benefits were from offsetting coal plant emissions. A sensitivity analysis on size and region of emission reduction location showed that the NOx and SO2 benefits vary significantly (unlike CO2 benefits), but this variation had minimal effects on the total emissions reduction benefits. In comparison with economic investment costs, the scenario 1 emissions reduction benefits equal 49% of the total investment cost (in 2014 $million) on average. Spatial maps and heat maps are generated to illustrate the spatial and temporal variations in the emissions reduction benefits. DA - 2016/10// PY - 2016/10// DO - 10.1016/j.ecolecon.2016.07.010 VL - 130 SP - 263-276 J2 - Ecological Economics LA - en OP - SN - 0921-8009 UR - http://dx.doi.org/10.1016/j.ecolecon.2016.07.010 DB - Crossref ER - TY - JOUR TI - Scenario Analysis of Energy and Water Trade-Offs in the Expansion of a Dual Water System AU - Barker, Zachary A. AU - Stillwell, Ashlynn S. AU - Berglund, Emily Z. T2 - Journal of Water Resources Planning and Management AB - Using treated wastewater effluent (reclaimed water) for beneficial purposes can be a sustainable practice that reduces demand on potable networks. However, implementing reclaimed water networks can have unintended effects, specifically unintended increases in energy consumption. This case study employs multiperiod scenario analysis to examine energy consumption associated with the potable and reclaimed water systems for the Town of Cary, North Carolina. Using hydraulic planning models of both systems provided by the design engineers, the conveyance and additional treatment energy is tabulated. This method considers uncertainty in reclaimed water demand by varying the expected demand for each build out of the reclaimed water network. Differential electricity consumption is calculated as the difference between the electricity consumed to deliver reclaimed water through a secondary network compared to the electricity consumed to deliver the same volume through the potable water network. Demand uncertainty, in conjunction with spatial growth, is found to have large impacts on differential electricity consumption. Because of the high quality of wastewater effluent, no additional energy is required for treatment, causing the reclaimed water network to consume less energy than the business-as-usual scenario, where the demands are supplied via the potable network. The differential electricity consumption decreases with network expansion because the reclaimed water system becomes less energy efficient per unit volume with increasing flow rate, while the potable water system energy efficiency remains fairly constant. Understanding the trade-offs between water and energy when planning reclaimed water networks is important for sustainable resource management within the built environment. DA - 2016/12// PY - 2016/12// DO - 10.1061/(asce)wr.1943-5452.0000714 VL - 142 IS - 12 SP - 05016012 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(asce)wr.1943-5452.0000714 DB - Crossref KW - Reclaimed water KW - Energy KW - Landscape irrigation KW - Sustainability ER - TY - JOUR TI - Impact of asphalt concrete fatigue endurance limit definition on pavement performance prediction AU - Zeiada, W. A. AU - Underwood, B. S. AU - Kaloush, K. E. T2 - International Journal of Pavement Engineering AB - Many well-constructed Hot Mix Asphalt pavements have been in service for 40 or more years without any evidence of fatigue cracking. This field experience suggests that there exists a strain level, known as the fatigue endurance limit (FEL), below which an asphalt concrete pavement will not exhibit fatigue cracks. Several studies have been conducted to define and verify this limit. Each of these methods is associated with certain assumptions regarding the nature of the FEL and heretofore a comprehensive comparison of each has not been made using a consistent set of mixtures. Likewise, the impact of any observed differences in FEL on the predicted pavement performance has not been made. This paper investigates and compares six different methods for identifying the FEL: NCHRP 9–44A approach, simplified viscoelastic continuum damage model, smeared-healing with continuum damage model, plateau value approach, pseudo-strain analysis method, and reduced cycles method. Each method is found to yield different values ranges from approximately 30–170 microstrains at 21.1 °C. The predicted FEL from each of the six methods are then used with the mechanistic empirical design algorithm to evaluate their effects on predicted pavement performance. Simulation outputs show different pavement performance and perpetual pavement structural design thicknesses from each of the methods. The study outcomes are expected to benefit future field verification research of FEL as it provides comprehensive analyses using six different methods. This future verification research may indicate the method that best represents actual perpetual pavement design and performance. DA - 2016/1/8/ PY - 2016/1/8/ DO - 10.1080/10298436.2015.1127372 VL - 18 IS - 11 SP - 945-956 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2015.1127372 DB - Crossref KW - Asphalt concrete KW - endurance limit KW - healing KW - damage KW - fatigue ER - TY - JOUR TI - Mechanistic-empirical methodology for the selection of cost-effective rehabilitation strategy for flexible pavements AU - Nobakht, Mona AU - Sakhaeifar, Maryam S. AU - Newcomb, David AU - Underwood, Shane T2 - International Journal of Pavement Engineering AB - A well-planned rehabilitation approach helps agencies to optimise the allocation of annual investment in pavement rehabilitation programs. Currently, many agencies are struggling with the selection of an optimal time-based and cost-effective rehabilitation solution to address the long-term needs of pavements. This study offers the use of a mechanistic-empirical methodology to develop a series of time-based rehabilitation strategies for high traffic volume flexible pavements located in Oklahoma. Six different pavement family groups are identified in the state, and comprehensive evaluation of existing pavements are conducted through analysis of falling weight deflectometer data and performance measures available in Oklahoma Pavement Management System database. The inadequacy of performance measures to fully characterise the condition of existing pavements are indicated, and damage factor determined from FWD data are suggested as trigger factor to select rehabilitation candidates. Three levels of rehabilitation activities including light, medium and heavy are considered as potential alternatives for rehabilitation candidates. A mechanistic-empirical methodology is employed to obtain an estimate of the performance of rehabilitation and extension in service lives of pavements. Also, an assessment output matrix is developed, which can be served as a supplemental tool to help the decision-makers in the highway agency with the rehabilitation related decision-making process. Cost-effectiveness of rehabilitation alternatives is determined through life cycle cost analysis, and three time-based renewal solutions are developed for pavement family groups that are in need of rehabilitation. DA - 2016/7/4/ PY - 2016/7/4/ DO - 10.1080/10298436.2016.1199878 VL - 19 IS - 8 SP - 675-684 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2016.1199878 DB - Crossref KW - Rehabilitation strategy KW - mechanistic-empirical analysis KW - pavement performance KW - falling weight deflectometer testing KW - life cycle cost analysis ER - TY - JOUR TI - Ruminants Contribute Fecal Contamination to the Urban Household Environment in Dhaka, Bangladesh AU - Harris, Angela R. AU - Pickering, Amy J. AU - Harris, Michael AU - Doza, Solaiman AU - Islam, M. Sirajul AU - Unicomb, Leanne AU - Luby, Stephen AU - Davis, Jennifer AU - Boehm, Alexandria B. T2 - Environmental Science & Technology AB - In Dhaka, Bangladesh, the sensitivity and specificity of three human, three ruminant, and one avian source-associated QPCR microbial source tracking assays were evaluated using fecal samples collected on site. Ruminant-associated assays performed well, whereas the avian and human assays exhibited unacceptable cross-reactions with feces from other hosts. Subsequently, child hand rinses (n = 44) and floor sponge samples (n = 44) from low-income-households in Dhaka were assayed for fecal indicator bacteria (enterococci, Bacteroidales, and Escherichia coli) and a ruminant-associated bacterial target (BacR). Mean enterococci concentrations were of 100 most probable number (MPN)/2 hands and 1000 MPN/225 cm(2) floor. Mean concentrations of Bacteroidales were 10(6) copies/2 hands and 10(5) copies/225 cm(2) floor. E. coli were detected in a quarter of hand rinse and floor samples. BacR was detected in 18% of hand rinse and 27% of floor samples. Results suggest that effective household fecal management should account not only for human sources of contamination but also for animal sources. The poor performance of the human-associated assays in the study area calls into the question the feasibility of developing a human-associated marker in urban slum environments, where domestic animals are exposed to human feces that have been disposed in pits and open drains. DA - 2016/4/19/ PY - 2016/4/19/ DO - 10.1021/acs.est.5b06282 VL - 50 IS - 9 SP - 4642-4649 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.5b06282 DB - Crossref ER - TY - JOUR TI - Occurrence of Host-Associated Fecal Markers on Child Hands, Household Soil, and Drinking Water in Rural Bangladeshi Households AU - Boehm, Alexandria B. AU - Wang, Dan AU - Ercumen, Ayse AU - Shea, Meghan AU - Harris, Angela R. AU - Shanks, Orin C. AU - Kelty, Catherine AU - Ahmed, Alvee AU - Mahmud, Zahid Hayat AU - Arnold, Benjamin F. AU - Chase, Claire AU - Kullmann, Craig AU - Colford, John M., Jr. AU - Luby, Stephen P. AU - Pickering, Amy J. T2 - Environmental Science & Technology Letters AB - We evaluated whether provision and promotion of improved sanitation hardware (toilets and child feces management tools) reduced rotavirus and human fecal contamination of drinking water, child hands, and soil among rural Bangladeshi compounds enrolled in a cluster-randomized trial. We also measured host-associated genetic markers of ruminant and avian feces. We found evidence of widespread ruminant and avian fecal contamination in the compound environment; non-human fecal marker occurrence scaled with animal ownership. Strategies for controlling non-human fecal waste should be considered when designing interventions to reduce exposure to fecal contamination in low-income settings. Detection of a human-associated fecal marker and rotavirus was rare and unchanged by provision and promotion of improved sanitation to intervention compounds. The sanitation intervention reduced ruminant fecal contamination in drinking water and general (non-host specific) fecal contamination in soil but overall had limited effects on reducing fecal contamination in the household environment. DA - 2016/10/19/ PY - 2016/10/19/ DO - 10.1021/acs.estlett.6b00382 VL - 3 IS - 11 SP - 393-398 J2 - Environ. Sci. Technol. Lett. LA - en OP - SN - 2328-8930 2328-8930 UR - http://dx.doi.org/10.1021/acs.estlett.6b00382 DB - Crossref ER - TY - CONF TI - Fluid shear variation potentially plays a role in aerobic granular sludge formation AU - Weaver, J.E. AU - Ducoste, J.J. AU - Reyes, F.L. C2 - 2016/// C3 - WEFTEC 2016 - 89th Water Environment Federation Annual Technical Exhibition and Conference DA - 2016/// VL - 3 SP - 5737-5744 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85070715342&partnerID=MN8TOARS ER - TY - CHAP TI - A Proteomic-Based Quantitative Analysis of the Relationship Between Monolignol Biosynthetic Protein Abundance and Lignin Content Using TransgenicPopulus trichocarpa AU - Wang, Jack P. AU - Tunlaya-Anukit, Sermsawat AU - Shi, Rui AU - Yeh, Ting-Feng AU - Chuang, Ling AU - Isik, Fikret AU - Yang, Chenmin AU - Liu, Jie AU - Li, Quanzi AU - Loziuk, Philip L. AU - Naik, Punith P. AU - Muddiman, David C. AU - Ducoste, Joel J. AU - Williams, Cranos M. AU - Sederoff, Ronald R. AU - Chiang, Vincent L. T2 - Recent Advances in Polyphenol Research AB - As part of a long-term project to develop a predictive model of lignin biosynthesis in the stem differentiating xylem of Populus trichocarpa, we explored the quantitative relationships of gene-specific monolignol pathway proteins and the amount of the lignin polymer. We determined the absolute abundance of monolignol pathway proteins in wild-type (Nisqually-1) and 80 transgenic trees, downregulated for the expression of genes in the monolignol pathway. Total lignin content for wild-type and transgenics ranged from 9.4 to 24.2%. Comparison of protein variation with lignin content showed that the proteins are produced in several-fold excess, suggesting that the monolignol pathway is highly homeostatic. Strong downregulation of xylem-specific PtrPAL2, 4, and 5 showed the most direct relationship with lignin content. These results are consistent with the Predictive Kinetic Metabolic Flux (PKMF) model of Wang et al., based on differential equations of mass action kinetics. Functional redundancy of multiple genes also moderates gene-specific effects. In addition, targeted production of specific proteins may affect the concentration of nontarget monolignol proteins, suggesting a yet-to-be-described level of coordinated control. PY - 2016/12/27/ DO - 10.1002/9781118883303.ch4 VL - 5 SP - 89-107 OP - PB - John Wiley & Sons, Ltd SN - 9781118883303 9781118883266 UR - http://dx.doi.org/10.1002/9781118883303.ch4 DB - Crossref ER - TY - JOUR TI - Instructional Design for Online Learning Environments and the Problem of Collaboration in the Cloud AU - Mehlenbacher, Brad AU - Kelly, Ashley Rose AU - Kampe, Christopher AU - Kittle Autry, Meagan T2 - Journal of Technical Writing and Communication AB - To investigate how college students understand and use cloud technology for collaborative writing, the authors studied two asynchronous online courses, on science communication and on technical communication. Students worked on a group assignment (3–4 per group) using Google Docs and individually reflected on their experience writing collaboratively. This article explores leadership and how it interacts with team knowledge making and the collaborative writing process. Guidelines are outlined for instructors interested in adopting collaborative, cloud-based assignments, and the tension between providing clear instructional guidance for student teams and allowing teams to embrace the ambiguity and messiness of virtual collaboration are discussed. DA - 2016/11/16/ PY - 2016/11/16/ DO - 10.1177/0047281616679112 VL - 48 IS - 2 SP - 199-221 J2 - Journal of Technical Writing and Communication LA - en OP - SN - 0047-2816 1541-3780 UR - http://dx.doi.org/10.1177/0047281616679112 DB - Crossref ER - TY - JOUR TI - Year in Review AU - Gabr, Mohammed T2 - J. Geotech. Geoenviron. Eng. DA - 2016/5// PY - 2016/5// DO - 10.1061/(asce)gt.1943-5606.0001510 VL - 142 IS - 5 SP - 01616001 ER - TY - JOUR TI - SUBGRADE RESILIENT MODULUS PREDICTION FROM LIGHT WEIGHT DEFLECTOMETER AU - Mousavi, S. Hamed AU - Gabr, Mohammed AU - Borden, Roy T2 - Canadian Geotechnical Journal AB - Resilient modulus has been used for decades as an important parameter in pavement structure design. Resilient modulus, like other elasticity moduli, increases with increasing confining stress and decreases with increasing deviatoric stress. Several constitutive models have been proposed in the literature to calculate resilient modulus as a function of stress state. The most recent model, recommended by the Mechanistic–empirical pavement design guide (MEPDG) and used in this paper, calculates resilient modulus as a function of bulk stress, octahedral shear stress, and three fitting coefficients: k 1 , k 2 , and k 3 . Work in this paper presents a novel approach for predicting resilient modulus of subgrade soils at various stress levels based on light-weight deflectometer (LWD) data. The proposed model predicts the MEPDG resilient modulus model coefficients (k 1 , k 2 , and k 3 ) directly from the ratio of applied stress to surface deflection measured during LWD testing. The proposed model eliminates uncertainties associated with needed input parameters for surface modulus (E LWD ) calculation, such as the selection of an appropriate value of Poisson’s ratio for the soil layer and shape factor. The proposed model was validated with independent data from other studies reported in the literature. DA - 2016/10// PY - 2016/10// DO - 10.1139/cgj-2016-0062 VL - 10 IS - 3 SP - 304–312 KW - resilient modulus KW - light-weight deflectometer KW - subgrade KW - Mechanistic-empirical pavement design guide ( MEPDG). ER - TY - JOUR TI - Health AU - Del Giudice, D. T2 - Science DA - 2016/// PY - 2016/// DO - 10.1126/science.354.6308.46 VL - 354 IS - 6308 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84990924181&partnerID=MN8TOARS ER - TY - JOUR TI - Describing the catchment-averaged precipitation as a stochastic process improves parameter and input estimation AU - Giudice, Dario Del AU - Albert, Carlo AU - Rieckermann, Jörg AU - Reichert, Peter T2 - Water Resour. Res. AB - Abstract Rainfall input uncertainty is one of the major concerns in hydrological modeling. Unfortunately, during inference, input errors are usually neglected, which can lead to biased parameters and implausible predictions. Rainfall multipliers can reduce this problem but still fail when the observed input (precipitation) has a different temporal pattern from the true one or if the true nonzero input is not detected. In this study, we propose an improved input error model which is able to overcome these challenges and to assess and reduce input uncertainty. We formulate the average precipitation over the watershed as a stochastic input process (SIP) and, together with a model of the hydrosystem, include it in the likelihood function. During statistical inference, we use “noisy” input (rainfall) and output (runoff) data to learn about the “true” rainfall, model parameters, and runoff. We test the methodology with the rainfall‐discharge dynamics of a small urban catchment. To assess its advantages, we compare SIP with simpler methods of describing uncertainty within statistical inference: (i) standard least squares (LS), (ii) bias description (BD), and (iii) rainfall multipliers (RM). We also compare two scenarios: accurate versus inaccurate forcing data. Results show that when inferring the input with SIP and using inaccurate forcing data, the whole‐catchment precipitation can still be realistically estimated and thus physical parameters can be “protected” from the corrupting impact of input errors. While correcting the output rather than the input, BD inferred similarly unbiased parameters. This is not the case with LS and RM. During validation, SIP also delivers realistic uncertainty intervals for both rainfall and runoff. Thus, the technique presented is a significant step toward better quantifying input uncertainty in hydrological inference. As a next step, SIP will have to be combined with a technique addressing model structure uncertainty. DA - 2016/3// PY - 2016/3// DO - 10.1002/2015wr017871 VL - 3 SP - n/a-n/a ER - TY - JOUR TI - Highway Vehicle Emissions Avoided by Diesel Passenger Rail Service Based on Real-World Data AU - Graver, Brandon M. AU - Frey, H. Christopher T2 - Urban Rail Transit AB - Avoided emissions attributable to the reduction in personal automobile trips for passenger rail riders are quantified based on real-world measurements. The North Carolina Department of Transportation (NCDOT) sponsors the Piedmont passenger rail service between Raleigh and Charlotte, NC. Per passenger-kilometer locomotive emissions were quantified based on portable emissions measurement system measured exhaust concentrations and duty cycles, or the fraction of trip time spent in each throttle notch setting of the prime mover engine, from 68 one-way trips of six Tier 0+ and Tier 1+ locomotives, and actual ridership data. Motor Vehicle Emissions Simulator (MOVES) software was used to estimate light-duty gasoline vehicle (LDGV) emission factors. Moving a passenger from an LDGV to a Piedmont train would lead to a net reduction in carbon dioxide (CO2) and carbon monoxide (CO) emissions by 44–94 %, respectively, between Raleigh and Charlotte, based on the assumption that the driver is the only LDGV passenger. However, locomotive nitrogen oxides (NO x ), hydrocarbons (HC), and particulate matter (PM) emission factors were 4–11 times higher than for the LDGV, respectively. Delays for either the train or highway vehicles did not substantially alter the key findings. If a Tier 4 locomotive was used, NO x , PM, and HC emission rates would be 90–99 % lower than current NCDOT locomotives. The use of real-world data representative of actual train operations provides an accurate basis for comparing rail and personal vehicle energy use and emissions and for identifying key factors affecting variability in the comparison. DA - 2016/12// PY - 2016/12// DO - 10.1007/s40864-016-0044-y VL - 2 IS - 3-4 SP - 153-171 UR - https://doi.org/10.1007/s40864-016-0044-y KW - Intercity rail KW - Energy intensity KW - Emissions KW - Carbon dioxide KW - Nitrogen oxides KW - Particulate matter ER - TY - MGZN TI - Highway Retaining Walls are Assets – A Risk-Based Approach for Managing Them AU - Gabr, M. AU - Butler, C. AU - Rasdorf, W. AU - Findley, D. AU - Bert, S. T2 - Geostrata DA - 2016/// PY - 2016/// M1 - March/April ER - TY - CONF TI - A Framework for Defining Asset Features to Monitor and Assess Earth Retaining Structures AU - Rasdorf, W. AU - Butler, C.J. AU - Findley, D.J. AU - Gabr, M.A. AU - Bert, S.A. T2 - Transportation Research Board 94th Annual Meeting C2 - 2016/1// C3 - Proceedings of the Transportation Research Board 94th Annual Meeting DA - 2016/1// SP - 16-0002 PB - Transportation Research Board of the National Academies ER - TY - CHAP TI - Traffic Engineering Studies AU - Findley, Daniel J. T2 - Traffic Engineering Handbook AB - Traffic engineering studies are used to obtain relevant empirical data, and that data must be collected in an unbiased, objective manner to result in appropriate decisions for improvements. The volume of vehicles, bicycles, or pedestrians is a key input to many traffic engineering analyses. Speed is an important measure for traffic operations, because highway users relate speed to economics, safety, time, comfort, and convenience. Analysts use the results of intersection and driveway studies to determine what kind of traffic control devices are warranted and to determine intersection capacity, traffic signal timing, site development impacts, safe speeds, driveway locations, and other important parameters. The development of a variety of technologies and techniques will assist transportation professionals and public officials with further refinement and future implementation. These technologies and techniques include new, more efficient, and more accurate data collection methods, as well as applications for real-time data analysis and integration. PY - 2016/2/19/ DO - 10.1002/9781119174738.ch4 SP - 109-148 OP - PB - John Wiley & Sons, Inc SN - 9781119174738 9781118762301 UR - http://dx.doi.org/10.1002/9781119174738.ch4 DB - Crossref ER - TY - CHAP TI - Atmospheric Plume Modeling with a Three-Dimensional Refinement Adaptive Grid Method AU - Odman, M. Talat AU - Hu, Yongtao AU - Garcia-Menendez, Fernando T2 - Springer Proceedings in Complexity AB - We present a three-dimensional fully-adaptive grid algorithm for chemical transport models. The method is designed to refine vertical and horizontal resolution by dynamically concentrating grid nodes within a region of interest. Exceptionally high grid resolution can be achieved in Eulerian air quality models using the method. Here the algorithm’s main operations are described. In addition, advection tests are used to demonstrate the algorithm’s ability to better capture concentration gradients in atmospheric plumes. PY - 2016/// DO - 10.1007/978-3-319-24478-5_67 SP - 409-413 OP - PB - Springer International Publishing SN - 9783319244761 9783319244785 UR - http://dx.doi.org/10.1007/978-3-319-24478-5_67 DB - Crossref ER - TY - JOUR TI - Evaluation of radar vehicle detection at four quadrant gate rail crossings AU - Horne, Dylan AU - Findley, Daniel J. AU - Coble, Daniel G. AU - Rickabaugh, Thomas J. AU - Martin, James B. T2 - Journal of Rail Transport Planning & Management AB - As train frequencies and traffic volumes increase, the need for safer at grade highway/rail crossings is paramount. Closing or grade separating crossings ultimately cannot work for all situations; therefore four quadrant gates may be used to provide a higher level of safety than conventional crossing treatments. At crossings between two adjacent signalized intersections, signal preemption may prevent vehicles from queuing within the crossing island, but some risk of vehicles becoming trapped by the timed exit gate descents still remains. Sensors can be installed to detect vehicles and would extend exit gate closure until the crossing island is clear or conversely allow for either simultaneous or near simultaneous entry and exit gate descents, if no vehicles are present. Radar detection was installed at three sites on North Carolina Railroad Company's H-Line in January 2014. Each crossing activation was broken down into 8 stages based on operating conditions of the gate system. The average duration of the time period when all gates are fully deployed increased considerably during the after period (when radar modified the exit gate behavior) by 10–17 s, providing a longer duration of a sealed crossing before the train arrived. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.jrtpm.2016.04.001 VL - 6 IS - 2 SP - 149-162 KW - Rail KW - Crossing KW - Highway KW - Radar KW - Detection KW - Intersection ER - TY - CONF TI - Geospatial variation of real-world emissions from a passenger car AU - Khan, T. AU - Frey, H.C. C2 - 2016/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2016/// VL - 4 SP - 2799-2822 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014820615&partnerID=MN8TOARS ER - TY - JOUR TI - Satellite‐based empirical models linking river plume dynamics with hypoxic area and volume AU - Le, Chengfeng AU - Lehrter, John C. AU - Hu, Chuanmin AU - Obenour, Daniel R. T2 - Geophysical Research Letters AB - Abstract Satellite‐based empirical models explaining hypoxic area and volume variation were developed for the seasonally hypoxic (O 2 < 2 mg L −1 ) northern Gulf of Mexico adjacent to the Mississippi River. Annual variations in midsummer hypoxic area and volume were related to Moderate Resolution Imaging Spectroradiometer‐derived monthly estimates of river plume area (km 2 ) and average, inner shelf chlorophyll a concentration (Chl a , mg m −3 ). River plume area in June was negatively related with midsummer hypoxic area (km 2 ) and volume (km 3 ), while July inner shelf Chl a was positively related to hypoxic area and volume. Multiple regression models using river plume area and Chl a as independent variables accounted for most of the variability in hypoxic area ( R 2 = 0.92) or volume ( R 2 = 0.89). These models explain more variation in hypoxic area than models using Mississippi River nutrient loads as independent variables. The results here also support a hypothesis that confinement of the river plume to the inner shelf is an important mechanism controlling hypoxia area and volume in this region. DA - 2016/3/16/ PY - 2016/3/16/ DO - 10.1002/2015GL067521 VL - 43 IS - 6 SP - 2693-2699 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 1944-8007 UR - http://dx.doi.org/10.1002/2015GL067521 DB - Crossref ER - TY - CONF TI - Enhanced Appearance-Based Material Classification for the Monitoring of Operation-Level Construction Progress through the Removal of Occlusions AU - Han, Kevin K. AU - Muthukumar, Banu AU - Golparvar-Fard, Mani AB - Tracking and visualizing the status of work-in-progress on construction sites can minimize the gap between short-term and long-term planning and lower coordination costs. Over the past few years, there have been studies on leveraging appearance information in point clouds and 4D building information models (BIM) to automatically detect progress deviations. These methods rely on libraries of construction material images to train the underlying material recognition models. Areas of the images corresponding to BIM elements are extracted and tested with the trained material recognition model. While successful results have been achieved, these extracted images contain occlusions that cause some BIM elements to be misclassified. To improve the accuracy, this paper presents a method that removes occlusions prior to performing material recognition. By creating 3D depth maps and simple linear iterative clustering (SLIC) superpixels, occlusions presented in the images are removed. The presented method is validated with four case studies. The experimental result shows the improved accuracies compared against that of the previous method without occlusion removal. C2 - 2016/5// C3 - Construction Research Congress 2016 DA - 2016/5// DO - 10.1061/9780784479827.089 PB - American Society of Civil Engineers ER - TY - RPRT TI - EconWorks tools for assessing the wider economic benefits of transportation implementation assistance AU - Hurtado, D.C. AU - Yang, R. AU - Bardaka, Eleni AU - Gkritza, K. AU - Fricker, J. AB - The Indiana Department of Transportation (INDOT) is undertaking efforts to assess the potential economic development benefits associated with highway corridor improvements at the middle-stage planning level. The primary objective of this research is to demonstrate and document the use of the EconWorks W.E.B. (wider economic benefits) tools for assessing the wider economic benefits (reliability, accessibility, and intermodal connectivity) of transportation projects in the State of Indiana. A parallel analysis of selected projects using TREDIS was also conducted in order to compare the relative merit or synergies between the tools. DA - 2016/// PY - 2016/// DO - 10.5703/1288284316553 ER - TY - JOUR TI - Flood forecasting a global perspective foreword AU - Vogel, R. M. AU - Arumugam, Sankarasubramanian T2 - Flood Forecasting: A Global Perspective DA - 2016/// PY - 2016/// DO - 10.1016/b978-0-12-801884-2.10000-3 SP - XVII- ER - TY - JOUR TI - horizontal and vertical alignment AU - Findley, D. J. T2 - Highway Engineering: Planning, Design, and Operations 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 - 2016/// PY - 2016/// DO - 10.1016/b978-0-12-801248-2.00003-4 SP - 89-166 ER - TY - JOUR TI - Highway geometric design AU - Findley, D. J. T2 - Highway Engineering: Planning, Design, and Operations 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 - 2016/// PY - 2016/// DO - 10.1016/b978-0-12-801248-2.00004-6 SP - 167-253 ER - TY - JOUR TI - Highway engineering planning, design, and operations introduction AU - Findley, D. J. T2 - Highway Engineering: Planning, Design, and Operations DA - 2016/// PY - 2016/// SP - 1-16 ER - TY - JOUR TI - Updating State and Local Highway Cost Allocation and Revenue Attribution: A Case Study for Indiana AU - Agbelie, Bismark R. D. K. AU - Volovski, Matthew AU - Zhang, Zhibo AU - Bardaka, Eleni AU - Labi, Samuel AU - Sinha, Kumares C. T2 - TRANSPORTATION RESEARCH RECORD AB - This study investigated the responsibility for the cost of upkeep of the highway infrastructure and the contribution of revenue from highway users on that upkeep. The costs consisted of actual expenditures on the construction, preservation, maintenance, and operation of the infrastructure at both the state and the local levels. The revenues from the federal, state, and local levels were assessed and considered. The types of assets included were pavement, bridge, safety, and mobility assets. The highway users were represented by the 13 FHWA vehicle classes, and the study was based on data on the expenditures made and the revenues collected from 2009 to 2012. The study framework duly recognized the dichotomy between attributable and common costs: for allocation of the attributable costs to the vehicle classes, equivalent single-axle loads, AASHTO load equivalency factors, and passenger car equivalents were used, and for allocation of common costs, the number of vehicle miles traveled adjusted for vehicle width was used. Of the 13 vehicle classes, Vehicle Classes 1 to 4 (passenger vehicles) were found to be overpaying their cost responsibilities, whereas Vehicle Classes 5 to 13 (trucks) were found to be underpaying. In particular, Vehicle Class 2 (automobiles) was found to overpay its cost responsibility by 10%, whereas Vehicle Class 9 (five-axle trucks) was found to underpay by 19%. The product of this study facilitates assessment of the appropriateness of the types and rates of current taxes and fees and provides a data-based and objective platform for devising future funding mechanisms and establishing appropriate user rates to meet Indiana’s future financing needs. DA - 2016/// PY - 2016/// DO - 10.3141/2597-01 VL - 2597 IS - 2597 SP - 1-10 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976286711&partnerID=MN8TOARS ER - TY - JOUR TI - Statistical Assessment of the Cost Effectiveness of Highway Pavement Warranty Contracts AU - Bardaka, Eleni AU - Zhang, Zhibo AU - Labi, Samuel AU - Sinha, Kumares C. AU - Mannering, Fred T2 - JOURNAL OF INFRASTRUCTURE SYSTEMS AB - The evaluation of warranty contracts is of great interest to highway agencies that seek innovative ways to manage their assets in the most cost-effective way. This paper demonstrates a statistical approach for evaluating the long-term performance and cost effectiveness of pavement warranties via comparison with similar traditional contracts. This is in contrast to past studies that used descriptive statistics and one-to-one comparisons to evaluate the performance of these two contracting approaches. In this study, random-parameter regression models that account for unobserved heterogeneity were developed to evaluate the performance of warranty and traditional contracts for similar projects on the basis of resulting pavement service life. The projects studied involved structural hot-mix asphalt overlay of crack-and-seat rigid pavements. The warranty projects in the study data sample were found to be 10% more effective in terms of average service life compared with traditional contract projects. Additionally, routine maintenance expenditures after the warranty period were up to 194% higher for traditional contract projects. These results suggest that warranty contracts have higher initial and rest-of-life quality. However, in terms of cost effectiveness (herein defined as the ratio of condition or longevity to lifecycle cost), the results suggest that the traditional contracts in the sample were 6–15% more cost-effective, on average, compared with their warranty counterparts, which could be attributed to warranty contracts’ higher costs. DA - 2016/9// PY - 2016/9// DO - 10.1061/(asce)is.1943-555x.0000299 VL - 22 IS - 3 SP - SN - 1943-555X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84982256765&partnerID=MN8TOARS KW - Warranty KW - Cost effectiveness KW - Service life ER - TY - CONF TI - Effect of as-compacted moisture content and density on pavement performance in different climatic regimes AU - Palanievelu, P. AU - Zapata, C.E. AU - Underwood, B.S. AB - While asphalt-concrete layer properties are more sensitive towards temperature variations, the subgrade stiffness have proven to be quite sensitive to moisture content fluctuations. When embankments are needed during the pavement construction, the soil must be compacted at a particular moisture-density condition to reach homogeneous properties. Due to construction variability, the as-compacted conditions might vary from the required specifications. This is of particular interest when dealing with compacted fine grained subgrade materials due to the influence of soil permeability in the seasonal moisture content fluctuation. The main objective of this study is the evaluation of the structural capacity and pavement performance due to the variability associated with the as-compacted moisture and density conditions, for different climatic regions. Three types of materials ranging from silt to clay were used in the analysis. Weather information from three locations was collected to represent different climate regimes. The pavement performance was analyzed using the Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure by using the response of the pavement to three major distresses: fatigue cracking, rutting and thermal cracking. Two different levels of input accuracy were compared: Level 2, which uses simple index material and compaction properties and Level 3, which uses just the simple index material properties to estimate the resilient modulus. Results indicated that the soil compacted to optimum moisture content predicted less amount of distress when compared to the wet or dry optimum conditions for the low plasticity soils; whereas the predicted distresses increase with the increase in the as-compacted moisture content for the high plasticity soils. When compared with ratio of optimum condition, IRI had a maximum increase of 5% in Chicago and Atlanta region exhibited a fatigue cracking increase of 40% while Phoenix area showed a lot of rutting increase of 30%. The difference in the distress results obtained for Level 2 and Level 3 analyses were not significant for the soil compacted at optimum condition, but the dry and wet of optimum conditions resulted in significant larger differences that depended on the location or climate where the pavement is constructed. C2 - 2016/// C3 - Proceedings of the Joint Geotechnical and Structural Engineering Congress DA - 2016/// DO - 10.1061/9780784479742.109 ER - TY - CONF TI - Assessing the socioeconomic effects of transit rail development: An exploration of displacement and gentrification AU - Bardaka, E. AU - Pyrialakou, D. AU - Gkritza, K. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - CONF TI - Using repeated stress sweep to investigate non-linearity in asphalt binders and mastics by fourier transform analysis AU - Gundla, A. AU - Underwood, B.S. C2 - 2016/// C3 - Proceedings International Society on Asphalt Pavements Symposium DA - 2016/// ER - TY - CONF TI - Use of particulate composite models and crumb rubber swelling to estimate stiffness of rubberized asphalt binders AU - Medina, J. AU - Underwood, B.S. C2 - 2016/// C3 - International Society on Asphalt Pavements Symposium DA - 2016/// ER - TY - CONF TI - The implications of uniform distribution of trucks on flexible pavement performance and design AU - Noorvand, H. AU - Underwood, B.S. AU - Sai, G. C2 - 2016/// C3 - Arizona ITE-IMSA Annual Spring Conference DA - 2016/// ER - TY - CONF TI - Reliability analysis of fatigue life prediction from the viscoelastic continuum damage model AU - Gudipudi, P. AU - Underwood, B.S. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - CONF TI - Potential for impacts of autonomous vehicles on pavement infrastructure AU - Noorvand, H. AU - Underwood, B.S. C2 - 2016/// C3 - 2016 Roads and Streets Conference DA - 2016/// ER - TY - JOUR TI - Investigation of aging in hydrated lime and portland cement modified asphalt concrete at multiple length scales AU - Gundla, A. AU - Gudipudi, P. AU - Medina, J. AU - Salim, R. AU - Zeiada, W. AU - Underwood, B.S. T2 - Journal of Materials in Civil Engineering DA - 2016/// PY - 2016/// VL - 28 IS - 5 ER - TY - CONF TI - Impact of forecasted freight trends on highway pavement infrastructure AU - Nagarajan, S. AU - Khalil, J. AU - Underwood, B.S. C2 - 2016/// C3 - Arizona ITE-IMSA Annual Spring Conference DA - 2016/// ER - TY - CONF TI - Fatigue performance prediction of asphalt composites subjected to cyclic loading with intermittent rest periods AU - Karki, P. AU - Bhasin, A. AU - Underwood, B.S. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - CONF TI - Evaluation of the sensitivity of asphalt concrete modulus to binder oxidation with a multiple length scale study AU - Gundla, A. AU - Gudipudi, P. AU - Underwood, B.S. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - CONF TI - Effect of binder modification on the performance of an ultrathin overlay pavement preservation strategy AU - Mogawer, W. AU - Austerman, A.A. AU - Underwood, B.S. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - JOUR TI - Effect of binder modification on the performance of an ultrathin overlay pavement preservation strategy AU - Mogawer, W. AU - Austerman, A.A. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2016/// PY - 2016/// SP - 1-7 ER - TY - CONF TI - Durable fiber reinforced asphalt concrete friction courses for airfield runways AU - Stempihar, J. AU - Underwood, B.S. AU - Nazar, S. AU - Kaloush, K. C2 - 2016/// C3 - Proceedings International Society on Asphalt Pavements Symposium DA - 2016/// ER - TY - CONF TI - Development of test protocol to measure axial fatigue damage and healing AU - Zeiada, W. AU - Kaloush, K. AU - Underwood, B.S. AU - Mamlouk, M. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - JOUR TI - Development of test protocol to measure axial fatigue damage and healing AU - Zeiada, W. AU - Kaloush, K. AU - Underwood, B.S. AU - M., Mamlouk T2 - Transportation Research Record DA - 2016/// PY - 2016/// SP - 10-18 ER - TY - CONF TI - Developing an indicator for fatigue cracking in hot mix asphalt pavements using viscoelastic continuum damage principles AU - Mensching, D. AU - Daniel, J.S. AU - Underwood, B.S. C2 - 2016/// C3 - 8th International RILEM Conference on Mechanisms of Cracking and Debonding in Pavements DA - 2016/// ER - TY - CONF TI - A nonlinear viscoelastic damage model for asphalt binder and mastics AU - Underwood, B.S. C2 - 2016/// C3 - 1st Transportation Research Congress DA - 2016/// ER - TY - CONF TI - 3D measurement of pavement macrotexture using digital stereoscopic vision AU - Medeiros, M. AU - Underwood, B.S. AU - Castorena, C. AU - Rupnow, T. AU - Rawls, M. C2 - 2016/// C3 - 95th Annual Meeting of the Transportation Research Board DA - 2016/// ER - TY - JOUR TI - Reliability Analysis of Fatigue Life Prediction from the Viscoelastic Continuum Damage Model AU - Gudipudi, Padmini P. AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The fatigue resistance of asphalt concrete materials plays an important role in the service life of a pavement. Several empirical and mechanistic models and efforts are under way toward improving these models for accurate prediction of fatigue life. The reliability of predictions with these models has not received substantial attention. This study used the simplified viscoelastic continuum damage model to analyze the reliability of fatigue predictions. Modulus and fatigue tests were conducted on a standard dense graded asphalt mixture to characterize the model and create deterministic fatigue life predictions. Monte Carlo simulations were then used to calculate the reliability of the fatigue predictions, given the variation in input parameters. The analysis was conducted for combinations of three experimental failure criteria and two model failure criteria at two strain levels for a total of 12 study cases. Differences in reliability between the combinations of failure conditions are identified and discussed. There are three major findings of this study. First, depending on the selection of failure criteria, the prediction errors could range from ±22% to ±52% at a 50% level of reliability, depending on the exact combination of failure criterion and strain level. Second, with an experimental failure criterion of 50%, modulus reduction shows better reliability regardless of the model failure criterion chosen to predict fatigue life. Third, the model failure criterion based on constant pseudostiffness at failure was found to be more reliable than was the pseudostrain energy release rate criterion when characterization was performed with three tests. DA - 2016/1// PY - 2016/1// DO - 10.3141/2576-10 VL - 2576 IS - 1 SP - 91-99 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2576-10 DB - Crossref ER - TY - JOUR TI - Identifying indicators for fatigue cracking in hot mix asphalt pavements using viscoelastic continuum damage principles AU - Mensching, D. AU - Daniel, J. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2016/// PY - 2016/// VL - 2576 SP - 28-39 ER - TY - JOUR TI - Fatigue Performance Prediction of Asphalt Composites Subjected to Cyclic Loading with Intermittent Rest Periods AU - Karki, Pravat AU - Bhasin, Amit AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - This study investigated the use of a unified method to predict the fatigue cracking and self-healing characteristics of asphalt composites subjected to cyclic loading and intermittent rest periods. Displacement-controlled uniaxial tests were performed on cylindrical specimens of two asphalt composites with intermittent rest periods. Fatigue damage and healing behavior were modeled with their stress–strain history with viscoelastic continuum damage mechanics. An integrated method to predict the number of cycles required to degrade the materials by a certain amount with and without rest periods was devised and verified with actual cyclic test results in the tension–compression mode of loading. DA - 2016/1// PY - 2016/1// DO - 10.3141/2576-08 VL - 2576 IS - 1 SP - 72-82 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2576-08 DB - Crossref ER - TY - CONF TI - Understanding the role of cost, impact, and equity in point and non-point source nutrient reductions for basin scale stream water quality improvement AU - Al-Amine, S. AB - Following the several cases of impairments and rapid degradations in water quality in late nineteen century in the US, The environmental agencies, including U.S. Environmental Protection Agency (USEPA) and the U.S. Department of Agriculture (USDA) were directed to set criteria for nutrients in rivers, lakes, and estuaries. As part of the Clean Water Action Plan, the USEPA set different criteria for point and non-point source nutrient loading reductions to improve stream water quality. While the nutrient reduction plans mandated different nutrient reduction goals for point and non-point sources, they were also associated with cost and equity issues for discharges who share a common stream but have different impacts based on the watershed characteristics. This study took Neuse Nutrient Sensitive Waters Management Strategy adopted by North Carolina Environmental Management Commission as an analytical example, to analyze the historical nutrient reduction practices by designated point and agricultural non-point sources to understand the role of impacts and equities in nutrient reduction performances in basin scale. Cost functions were developed for points and non-point sources based on literatures and minimum cost solutions were developed to meet nutrient reduction goals under different equity assumptions. The study provides useful information for understanding the complex response of individual polluters in managing a shared stream resource. The results can be useful for developing regulations for efficient water quality trading markets and understanding potentials and barriers of point and non-point source dischargers trading under regulations in long term planning horizon. C2 - 2016/// C3 - World Environmental and Water Resources Congress 2016: Professional Development, Innovative Technology, International Perspectives, and History and Heritage DA - 2016/// DO - 10.1061/9780784479841.022 SP - 193-202 ER - TY - CONF TI - Coupling agent-based and groundwater modeling to explore demand management strategies for shared resources AU - Al-Amin, S. AU - Berglund, E. Z. AU - Mahinthakumar, K. AB - Municipal water demands in growing population centers in the arid southwest U.S. are typically met through increased groundwater withdrawals. Hydro-climatic uncertainties attributed to climate change and land use conversions may also alter demands and impact the replenishment of groundwater supply. Groundwater aquifers are not necessarily confined within municipal and management boundaries, and multiple diverse agencies may manage a shared resource in a decentralized approach, based on individual concerns and resources. The interactions among water managers, consumers, and the environment influence the performance of local management strategies and regional groundwater resources. This research couples an agent-based modeling (ABM) framework and a groundwater model to analyze the effects of different management approaches on shared groundwater resources. The ABM captures the dynamic interactions between household-level consumers and policy makers to simulate water demands under climate change and population growth uncertainties. The groundwater model is used to analyze the relative effects of management approaches on reducing demands and replenishing groundwater resources. 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. 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 - 2016/// C3 - World Environmental and Water Resources Congress 2016: Watershed Management, Irrigation and Drainage, and Water Resources Planning and Management DA - 2016/// DO - 10.1061/9780784479858.016 SP - 141-150 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 - 2016/9/24/ PY - 2016/9/24/ DO - 10.1007/s00477-015-1158-6 VL - 30 IS - 8 SP - 2255–2269 SN - 1436-3240 1436-3259 UR - http://dx.doi.org/10.1007/s00477-015-1158-6 ER - TY - JOUR TI - Probabilistically assessing the role of nutrient loading in harmful algal bloom formation in western Lake Erie AU - Bertani, Isabella AU - Obenour, Daniel R. AU - Steger, Cara E. AU - Stow, Craig A. AU - Gronewold, Andrew D. AU - Scavia, Donald T2 - JOURNAL OF GREAT LAKES RESEARCH AB - Harmful algal blooms (HABs) have increased in frequency and magnitude in western Lake Erie and spring phosphorus (P) load was shown to be a key driver of bloom intensity. A recently developed Bayesian hierarchical model that predicts peak bloom size as a function of Maumee River phosphorus load suggested an apparent increased susceptibility of the lake to HABs. We applied that model to develop load–response curves to inform revision of Lake Erie phosphorus load targets under the 2012 Great Lakes Water Quality Agreement. In this application, the model was modified to estimate the fraction of the particulate P (PP) load that becomes bioavailable, and it was recalibrated with additional bloom observations. Although the uncertainty surrounding the estimate of the bioavailable PP fraction is large, inclusion in the model improves prediction of bloom variability compared to dissolved reactive P (DRP) alone. The ability to characterize model and measurement uncertainty through hierarchical modeling allowed us to show that inconsistencies in bloom measurement represent a considerable portion of the overall uncertainty associated with load–response curves. The updated calibration also lends support to the system's apparent enhanced susceptibility to blooms. The temporal trend estimated by the model results in an upward shift of the load–response curve over time such that a larger load reduction is required to achieve a target bloom size today compared to earlier years. More research is needed to further test the hypothesis of a shift in the lake's response to stressors over time and, if confirmed, to explore underlying mechanisms. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.jglr.2016.04.002 VL - 42 IS - 6 SP - 1184-1192 SN - 0380-1330 KW - Cyanobacteria blooms KW - Phosphorus load KW - Bayesian hierarchical model ER - TY - JOUR TI - Legacy and Emerging Perfluoroalkyl Substances Are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina AU - Sun, Mei AU - Arevalo, Elisa AU - Strynar, Mark AU - Lindstrom, Andrew AU - Richardson, Michael AU - Kearns, Ben AU - Pickett, Adam AU - Smith, Chris AU - Knappe, Detlef R. U. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS AB - Long-chain per- and polyfluoroalkyl substances (PFASs) are being replaced by short-chain PFASs and fluorinated alternatives. For ten legacy PFASs and seven recently discovered perfluoroalkyl ether carboxylic acids (PFECAs), we report (1) their occurrence in the Cape Fear River (CFR) watershed, (2) their fate in water treatment processes, and (3) their adsorbability on powdered activated carbon (PAC). In the headwater region of the CFR basin, PFECAs were not detected in raw water of a drinking water treatment plant (DWTP), but concentrations of legacy PFASs were high. The U.S. Environmental Protection Agency’s lifetime health advisory level (70 ng/L) for perfluorooctanesulfonic acid and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid (PFPrOPrA), a replacement for PFOA, was 631 ng/L (n = 37). Six other PFECAs were detected, with three exhibiting chromatographic peak areas up to 15 times that of PFPrOPrA. At this DWTP, PFECA removal by coagulation, ozonation, biofiltration, and disinfection was negligible. The adsorbability of PFASs on PAC increased with increasing chain length. Replacing one CF2 group with an ether oxygen decreased the affinity of PFASs for PAC, while replacing additional CF2 groups did not lead to further affinity changes. DA - 2016/12// PY - 2016/12// DO - 10.1021/acs.estlett.6b00398 VL - 3 IS - 12 SP - 415-419 SN - 2328-8930 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85006081776&partnerID=MN8TOARS ER - TY - JOUR TI - Automatic Optical Crack Tracking for Double Cantilever Beam Specimens AU - Krull, B. AU - Patrick, J. AU - Hart, K. AU - White, S. AU - Sottos, N. T2 - EXPERIMENTAL TECHNIQUES DA - 2016/6// PY - 2016/6// DO - 10.1007/s40799-016-0094-9 VL - 40 IS - 3 SP - 937-945 SN - 1747-1567 KW - Fiber-Reinforced Composites KW - Mode I Fracture KW - Double Cantilever Beam KW - Machine Vision ER - TY - JOUR TI - A phase-field formulation for fracture in ductile materials: Finite defonnation balance law derivation, plastic degradation, and stress triaxiality effects AU - Borden, Michael J. AU - Hughes, Thomas J. R. AU - Landis, Chad M. AU - Anvari, Amin AU - Lee, Isaac J. T2 - COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING AB - Phase-field models have been a topic of much research in recent years. Results have shown that these models are able to produce complex crack patterns in both two and three dimensions. A number of extensions from brittle to ductile materials have been proposed and results are promising. To date, however, these extensions have not accurately represented strains after crack initiation or included important aspects of ductile fracture such as stress triaxiality. This work introduces a number of contributions to further develop phase-field models for fracture in ductile materials. These contributions include: a cubic degradation function that provides a stress–strain response prior to crack initiation that more closely approximates linear elastic behavior, a derivation of the governing equations in terms of a general energy potential from balance laws that describe the kinematics of both the body and phase-field, introduction of a yield surface degradation function that provides a mechanism for plastic softening and corrects the non-physical elastic deformations after crack initiation, a proposed mechanism for including a measure of stress triaxiality as a driving force for crack initiation and propagation, and a correction to an error in the configuration update of an elastoplastic return-mapping algorithm for J2 flow theory. We also present a heuristic time stepping scheme that facilitates computations that require a relatively long load time prior to crack initiation. A number of numerical results will be presented that demonstrate the effects of these contributions. DA - 2016/12/1/ PY - 2016/12/1/ DO - 10.1016/j.cma.2016.09.005 VL - 312 SP - 130-166 SN - 1879-2138 KW - Phase-field KW - Fracture KW - Plasticity KW - Triaxiality ER - TY - JOUR TI - Wind power generation: An impact analysis of incentive strategies for cleaner energy provision in Brazil AU - Aquila, Giancarlo AU - Souza Rocha, Luiz Celio AU - Rotela Junior, Paulo AU - Pamplona, Edson de Oliveira AU - Queiroz, Anderson Rodrigo AU - Paiva, Anderson Paulo T2 - JOURNAL OF CLEANER PRODUCTION AB - Brazil has adopted various strategies to encourage alternative renewable energy sources in pursuit of cleaner and sustainable energy production. To this end, strategies should support the reduction of the financial risk for potential investors in the renewable energy market. Therefore, this study aims to analyze the impact of incentive strategies on the financial risk of wind power generation projects in Brazil in different marketing environments. From a quantitative approach, using Monte Carlo Simulation in three scenarios, we evaluate the impact of funding from the National Development Bank and participation in the Clean Development Mechanism in the financial returns of the investor in a regulated contracting environment and free contracting environment, measured by the Net Present Value. We conduct a statistical analysis to find out if there were statistically significant differences in investor risk in each scenario. The main results of the study are as follows: the wind speed, the selling price of energy, and disbursement for the investment have the most significant impact on the financial return; the project viability probability is greater than 85% in all scenarios, regardless of the marketing environment; the regulated market is less risky for the producer than the free market, since there is a statistically significant difference in Net Present Value variances for all scenarios; in the regulated contracting environment, funding is critical to reducing risk; and carbon credit trading is not a suitable policy for providing financial security to renewable energy producers. Thus, we conclude that in Brazil the contracting of projects from auctions in the regulated contracting environment, with the support of the National Development Bank, has been important for neutralizing the producer's financial risks. DA - 2016/11/20/ PY - 2016/11/20/ DO - 10.1016/j.jclepro.2016.07.207 VL - 137 SP - 1100-1108 SN - 1879-1786 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84990942807&partnerID=MN8TOARS KW - Wind power KW - Stochastic analysis KW - Financial risk KW - Incentive strategies KW - Net present value ER - TY - CONF TI - The Use of Microbial Induced Calcite Precipitation to Reduce Trace Element Leaching from Fly Ash AU - Montoya, Brina M. AU - Safavizadeh, Shahin AU - Meredith, Ashley T2 - Geo-Chicago 2016 AB - North Carolina has recently been facing issues associated with the storage of coal ash, specifically preventing trace elements found in coal ash from leaching into the local groundwater. The research program presented herein focuses on reducing the leachability of trace elements found in coal ash using bio-mediated methods. Microbial induced calcite precipitation (MICP) is used to immobilize trace elements within the fly ash. The MICP process is initiated within ponded fly ash material set up in soil columns, and effluent is collected from the treated fly ash material. The concentrations of the trace elements are measured using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations within the MICP-treated fly ash effluent are compared to baseline fly ash effluent. The MICP treatment process is also applied to dry fly ash material that may be used within construction projects. The MICP treatment process was applied to fly ash material in a similar manner as moisture conditioning during compaction. The MICP treatment process was allowed to take place, then effluent samples were collected from percolating water. The MICP-treated leachate was compared to that of a baseline compacted fly ash sample and compared to the results from the ponded fly ash. C2 - 2016/8/8/ C3 - Geo-Chicago 2016 DA - 2016/8/8/ DO - 10.1061/9780784480144.098 SP - 989-997 M1 - 271 PB - American Society of Civil Engineers SN - 9780784480144 UR - http://dx.doi.org/10.1061/9780784480144.098 DB - Crossref ER - TY - JOUR TI - Strategies for Volumetric Recovery of Large Scale Damage in Polymers AU - Krull, Brett P. AU - Gergely, Ryan C. R. AU - Cruz, Windy A. Santa AU - Fedonina, Yelizaveta I. AU - Patrick, Jason F. AU - White, Scott R. AU - Sottos, Nancy R. T2 - ADVANCED FUNCTIONAL MATERIALS AB - The maximum volume that can be restored after catastrophic damage in a newly developed regenerative polymer system is explored for various mixing, surface wetting, specimen configuration, and microvascular delivery conditions. A two‐stage healing agent is implemented to overcome limitations imposed by surface tension and gravity on liquid retention within a damage volume. The healing agent is formulated as a two‐part system in which the two reagent solutions are delivered to a through‐thickness, cylindrical defect geometry by parallel microvascular channels in thin epoxy sheets. Mixing occurs as the solutions enter the damage region, inducing gelation to initiate an accretive deposition process that enables large damage volume regeneration. The progression of the damage recovery process is tracked using optical and fluorescent imaging, and the mixing efficiency is analyzed. Complete recovery of gaps spanning 11.2 mm in diameter (98 mm 2 ) is achieved under optimal conditions. DA - 2016/7/5/ PY - 2016/7/5/ DO - 10.1002/adfm.201600486 VL - 26 IS - 25 SP - 4561-4569 SN - 1616-3028 KW - regenerative polymers KW - microvascular KW - polymers KW - self-healing ER - TY - CONF TI - Relationship between On-Site Planning Efforts and Work Plan Reliability AU - Hosseini, S. A. A. AU - Howell, G. AU - Liu, M. C2 - 2016/// C3 - Construction Research Congress 2016: Old and New Construction Technologies Converge in Historic San Juan DA - 2016/// SP - 2129-2138 ER - TY - JOUR TI - Quantifying in situ growth rate of a filamentous bacterial species in activated sludge using rrna:rdna ratio AU - Nguyen, V. L. AU - He, X. AU - Reyes, F. L. T2 - FEMS Microbiology Letters AB - If the in situ growth rate of filamentous bacteria in activated sludge can be quantified, researchers can more accurately assess the effect of operating conditions on the growth of filaments and improve the mathematical modeling of filamentous bulking. We developed a method to quantify the in situ specific growth rate of Sphaerotilus natans (a model filament) in activated sludge using the species-specific 16S rRNA:rDNA ratio. Primers targeting the 16S rRNA of S. natans were designed, and real-time PCR and RT-PCR were used to quantify DNA and RNA levels of S. natans, respectively. A positive linear relationship was found between the rRNA:rDNA ratio (from 440 to 4500) and the specific growth rate of S. natans (from 0.036 to 0.172 h−1) using chemostat experiments. The in situ growth rates of S. natans in activated sludge samples from three water reclamation facilities were quantified, illustrating how the approach can be applied in a complex environment such as activated sludge. DA - 2016/// PY - 2016/// DO - 10.1093/femsle/fnw255 VL - 363 IS - 22 SP - fnw255 SN - 1574-6968 UR - http://dx.doi.org/10.1093/femsle/fnw255 KW - growth rate KW - filament KW - Sphaerotilus natans KW - rRNA:rDNA ratio KW - activated sludge KW - filamentous bulking ER - TY - CONF TI - Non-point source evaluation of groundwater contamination from agriculture under geologic and hydrologic uncertainty AU - Ayub, R. AU - Obenour, D. R. AU - Messier, K. P. AU - Serre, M. L. AU - Mahinthakumar, K. AB - The long-term effect of non-point source pollution on groundwater from agricultural practices is a major concern globally. Non-point source pollutants such as nitrate that occur through fertilizers and animal waste eventually make their way into the aquifer by infiltrating soil. The goal of this study is to characterize the probability distributions of non-point source locations and time release history of nitrate contamination into groundwater resources. A Bayesian framework using a Markov Chain Monte Carlo approach (MCMC) is developed to estimate posterior distributions of non-point sources by incorporating groundwater nitrate concentration data as well as geologic and hydrologic uncertainties. Hypothetical scenarios are used to test the approach and then apply it to a basin in North Carolina.The likelihood function computation involves a mechanistic model that simulates nitrate transport in groundwater from non-point agricultural sources and predicts nitrate concentrations at observation wells. Effectiveness of the proposed approach is tested through a convergence analysis of the MCMC algorithm. The Bayesian inference analysis methodology developed in this research will help decision makers and water managers identify potential source containment areas and to decide if further sampling is required. C2 - 2016/// C3 - World Environmental and Water Resources Congress 2016: Environmental, Sustainability, Groundwater, Hydraulic Fracturing, and Water Distribution Systems analysis DA - 2016/// DO - 10.1061/9780784479865.035 SP - 329-336 ER - TY - JOUR TI - New generation of precast concrete double tees reinforced by carbon-fiber-reinforced polymer grid response AU - Lunn, D. AU - Lucier, G. AU - Rizkalla, S. AU - Cleland, N. AU - Gleich, H. T2 - PCI Journal DA - 2016/// PY - 2016/// SP - 87-89 ER - TY - JOUR TI - Micromechanical Modeling of the Ratcheting Behavior of 304 Stainless Steel AU - Ben Naceur, I. AU - Sai, K. AU - Hassan, T. AU - Cailletaud, G. T2 - JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME AB - Numerical simulations of 304 austenitic stainless steel (SS304) cyclic and ratcheting responses are performed using polycrystalline plasticity models. On the basis of the polycrystalline model of Cailletaud and Pilvin (1994, “Utilisation de modèles polycristallins pour le calcul par éléments finis,” Rev. Eur. Élém. Finis, 3, pp. 515–541), a modification of the β rule that operates the transition between the macroscopic level and the grain level is proposed. The improvement of the transition rule is obtained by introducing a “memory variable” at the grain level, so that a better description of the local stress–strain behavior is provided. This new feature is calibrated by means of previous simulations using finite element (FE) aggregate models. The results of the updated polycrystalline plasticity model are in good agreement with the macroscopic responses. DA - 2016/4// PY - 2016/4// DO - 10.1115/1.4032154 VL - 138 IS - 2 SP - SN - 1528-8889 ER - TY - CONF TI - Metrics that matter: Evaluation of metrics and indicators for project progress measurement, performance assessment, and performance forecasting during construction AU - Orgut, R. E. AU - Batouli, M. AU - Zhu, J. AU - Mostafavi, A. AU - Jaselskis, E. J. AB - The subjective and inconsistent use and interpretation of metrics related to progress measurement, performance assessment, and performance forecasting is a major obstacle to understanding the actual conditions of a construction project. In order to foster metric standardization for project controls, this study focuses on the construction phase to identify core metrics in progress measurement, performance assessment, and forecasting. First, an extensive list of metrics was extracted from a comprehensive literature review of both academic and industry sources and reviewed by a panel of experts to ensure that no important metrics were excluded. Second, an online survey was created and distributed to industry practitioners to capture project-specific information regarding metric usage and interpretation. Finally, metrics were evaluated in terms of their usage and importance; these results were compared to statistical analyses of key metrics closely linked to better cost and schedule performance in construction projects. Comparison revealed the gaps between perceived and quantitative relevance of metrics to overall project performance. Results show that out of 17 highly rated qualitative core metrics, only one, schedule variance, was among 11 quantitatively effective metrics. C2 - 2016/// C3 - Construction Research Congress 2016: Old and New Construction Technologies Converge in Historic San Juan DA - 2016/// DO - 10.1061/9780784479827.020 SP - 189-198 ER - TY - CONF TI - Impact of training methods on hazard recognition and risk perception in construction AU - Zuluaga, C. M. AU - Namian, M. AU - Albert, A. AB - Disproportionate injury rates continue to be a major issue in the construction industry. Complex working conditions, and the challenges associated with detecting and managing hazards in dynamic environments are partly responsible for these high incident rates. To improve safety performance, employers provide hazard recognition and management training to workers. However, past research reveal that traditional training programs are inadequately designed, and do not facilitate efficient knowledge transfer. This study assessed the perception of training delivery methods, its impact on worker’s hazard recognition performance, and its subsequent influence on worker’s risk perception. Construction personnel from 49 projects in the United States were asked to identify training methods adopted by their organizations. In addition, the hazard recognition ability and risk perception of workers were assessed using a random sample of construction photographs captured from real projects. Strong statistical significance was found between the training’s level of engagement, hazard recognition performance and risk perception. The results of the study can be used by managers to select efficient training methods that will help improve hazard recognition, risk perception and overall safety performance. C2 - 2016/// C3 - Construction Research Congress 2016: Old and New Construction Technologies Converge in Historic San Juan DA - 2016/// DO - 10.1061/9780784479827.285 SP - 2861-2871 ER - TY - CONF TI - Exploring strategies for LID implementation in marginalized communities and urbanizing watersheds AU - Garcia-Cuerva, L. AU - Berglund, E. Z. AU - Rivers, L. AB - Increasing urbanization augments impervious surface area which results in increased run off volumes and peak flows. Low impact development (LID) approaches present a decentralized alternative for sustainable urban stormwater and provide water conservation opportunities. They also provide a wide array of ecosystem services and foster community building by enhancing neighborhood aesthetics, increasing property value, and providing shared green spaces. While projects involving sustainability concepts and environmental design are favored in privileged communities, marginalized communities have historically been located in areas that suffer from environmental degradation. Underprivileged communities typically do not receive as many social and environmental services as advantaged communities. This research develops a participatory decision-making approach to address environmental justice for marginalized communities and explore LID strategies at the watershed scale for improving hydrological performance and mitigating flooding. Focus groups are designed and conducted to solicit input from community members, stakeholders, and community advocates about sustainable stormwater management alternatives. Input will be used to develop LID strategies that meet community goals, such as maximizing the provision of ecosystem services, providing water conservation opportunities, and fostering community building. A hydrologic/hydraulic stormwater modeling system will be developed using HEC-HMS and SWMM to simulate the stormwater impacts of rain water harvesting systems, green roofs, and bioretention cells. This approach will be implemented for a marginalized community within the Walnut Creek Watershed in Raleigh, North Carolina. On-going research will seek further feedback from the community about LID strategies that are developed using the hydrologic/hydraulic modeling system to assess preferences about LID decisions and tradeoffs among design goals. C2 - 2016/// C3 - Water, Wastewater, and Stormwater and Urban Watershed Symposium DA - 2016/// DO - 10.1061/9780784479889.005 SP - 41-50 ER - TY - CONF TI - Critical factors that impact construction workers' hazard recognition performance AU - Namian, M. AU - Zuluaga, C. M. AU - Albert, A. AB - Most safety initiatives in the construction industry are implemented to manage recognized hazards. Therefore, proper hazard recognition is often the first step to develop effective field-based hazard management strategies. Despite its significance, recent research has demonstrated that construction workers are often unable to recognize hazards sufficiently in dynamic and rapidly changing environments. These unrecognized and unmanaged hazards can potentially result in catastrophic accidents and injuries. Although few studies have developed strategies to improve hazard recognition in general, a thorough understanding of factors impacting worker’s hazard recognition performance is lacking. In this study, through interviews with construction managers and safety professionals, and a thorough review of literature; 36 critical factors impacting worker’s hazard recognition were identified. Examining the identified factors revealed that a multilevel construct existed among factors, and consequently the underlying factors were clustered as personal, organizational, social, situational and industry-related, and miscellaneous factors. After compiling the factors, the participating experts reviewed the factors and validated the findings. The findings of this study can be used by practicing construction professionals to improve hazard recognition during pre-task safety meetings, and to develop a conductive climate that facilitates hazard recognition and management. C2 - 2016/// C3 - Construction Research Congress 2016: Old and New Construction Technologies Converge in Historic San Juan DA - 2016/// DO - 10.1061/9780784479827.275 SP - 2762-2772 ER - TY - CONF TI - An infrastructure maintenance funding framework for a transportation agency AU - Almalki, A. AU - Rasdorf, W. AU - Pilson, C. AU - Arnold, J. AU - Whitley, M. AB - Asset management (AM) is currently a key focus area for many transportation agencies. AM helps transportation departments improve their maintenance process, have better budget allocation strategies, and extend the useful life of their infrastructure at a lower cost. All state DOTs are looking for innovative ways to manage their infrastructure assets to obtain the best return for each dollar spent. The NCDOT collects roadway condition data (through sampling) from a random set of 0.1 mile segments of the road network to evaluate the condition of different asset features against certain thresholds to estimate the need for maintenance and to determine how to allocate maintenance funding. NCDOT’s maintenance management system (MMS) is used to determine expenditures to maintain assets, assess asset condition rating improvement due to each expenditure, forecast future condition ratings, and determine optimal funding and spending plans for each maintenance activity. The objective of this paper is to present a comprehensive framework for assessing road asset condition and allocating funding for asset condition maintenance. The framework seeks to maximize condition rating while minimizing cost based on NCDOT budget constraints. C2 - 2016/// C3 - Construction Research Congress 2016: Old and New Construction Technologies Converge in Historic San Juan DA - 2016/// DO - 10.1061/9780784479827.144 SP - 1435-1444 ER - TY - JOUR TI - A Reconciliation of Experimental and Analytical Results for Piping Systems AU - Ryu, Yonghee AU - Gupta, Abhinav AU - Jung, WooYoung AU - Ju, BuSeog T2 - INTERNATIONAL JOURNAL OF STEEL STRUCTURES DA - 2016/12// PY - 2016/12// DO - 10.1007/s13296-016-0019-6 VL - 16 IS - 4 SP - 1043-1055 SN - 2093-6311 KW - Validation KW - Piping system KW - Threaded and groove fit T-joints KW - Experimental tests KW - Nonlinear finite element model ER - TY - JOUR TI - Polymers with autonomous life-cycle control AU - Patrick, Jason F. AU - Robb, Maxwell J. AU - Sottos, Nancy R. AU - Moore, Jeffrey S. AU - White, Scott R. T2 - NATURE DA - 2016/12/15/ PY - 2016/12/15/ DO - 10.1038/nature21002 VL - 540 IS - 7633 SP - 363-370 SN - 1476-4687 ER - TY - JOUR TI - Least-cost path analysis and multi-criteria assessment for routing electricity transmission lines AU - Lima, Rodolfo Mendes AU - Osis, Reinis AU - Queiroz, Anderson Rodrigo AU - Moreira Santos, Afonso Henriques T2 - IET GENERATION TRANSMISSION & DISTRIBUTION AB - The classical approach for transmission line (TL) routing based on paper maps, aerial photographs and field visits can generate inconsistent results, besides being a time consuming and intensive labour activity. The application of methodologies based on geographic information system (GIS) combined with multi-criteria assessment (MCA) methods can generate time and cost savings on the planning step. However, this methodology still must be better assessed for its applicability and improvements can be made. Therefore, this study aims at verifying the applicability of a GIS methodology for TL routing using analytic hierarchy process (AHP) for weighting criteria. In addition, the effectiveness of AHP method is evaluated comparing the previously attained results with a route modelled using monetary values to weight the criteria. To achieve the objectives, the methodology is applied for an area in the northern region of Brazil (state of Pará) where a 230 kV TL is already implemented: the TL Vila do Conde-Castanhal. As a result, routes with lower length and lower total cost than the implemented TL were obtained, which suggest the potential benefits of applying the proposed methodology compared with traditional route planning, which does not use quantitative MCA and more advanced GIS tools. DA - 2016/12/8/ PY - 2016/12/8/ DO - 10.1049/iet-gtd.2016.1119 VL - 10 IS - 16 SP - 4222-4230 SN - 1751-8695 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85001033144&partnerID=MN8TOARS KW - power overhead lines KW - geographic information systems KW - cartography KW - analytic hierarchy process KW - power engineering computing KW - least-cost path analysis KW - multicriteria assessment methods KW - electricity transmission line routing KW - paper maps KW - aerial photographs KW - field visits KW - geographic information system systems KW - GIS systems KW - MCA methods KW - time saving generation KW - cost saving generation KW - TL routing KW - analytic hierarchy process KW - AHP KW - monetary values KW - northern region KW - Brazil KW - Para state KW - TL Vila do Conde-Castanhal KW - weighting criteria KW - voltage 230 kV ER - TY - JOUR TI - Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil AU - Won, Jongho AU - Borden, Robert C. T2 - JOURNAL OF CONTAMINANT HYDROLOGY AB - Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate >200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20g/m3/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.jconhyd.2016.08.008 VL - 194 SP - 1-9 SN - 1873-6009 KW - High explosives KW - TNT KW - RDX KW - HMX KW - Biodegradation ER - TY - JOUR TI - Eco-system optimal time-dependent flow assignment in a congested network AU - Lu, Chung-Cheng AU - Liu, Jiangtao AU - Qu, Yunchao AU - Peeta, Srinivas AU - Rouphail, Nagui M. AU - Zhou, Xuesong T2 - TRANSPORTATION RESEARCH PART B-METHODOLOGICAL AB - This research addresses the eco-system optimal dynamic traffic assignment (ESODTA) problem which aims to find system optimal eco-routing or green routing flows that minimize total vehicular emission in a congested network. We propose a generic agent-based ESODTA model and a simplified queueing model (SQM) that is able to clearly distinguish vehicles’ speed in free-flow and congested conditions for multi-scale emission analysis, and facilitates analyzing the relationship between link emission and delay. Based on the SQM, an expanded space-time network is constructed to formulate the ESODTA with constant bottleneck discharge capacities. The resulting integer linear model of the ESODTA is solved by a Lagrangian relaxation-based algorithm. For the simulation-based ESODTA, we present the column-generation-based heuristic, which requires link and path marginal emissions in the embedded time-dependent least-cost path algorithm and the gradient-projection-based descent direction method. We derive a formula of marginal emission which encompasses the marginal travel time as a special case, and develop an algorithm for evaluating path marginal emissions in a congested network. Numerical experiments are conducted to demonstrate that the proposed algorithm is able to effectively obtain coordinated route flows that minimize the system-wide vehicular emission for large-scale networks. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.trb.2016.09.015 VL - 94 SP - 217-239 SN - 1879-2367 KW - Green transportation KW - Vehicular emission modeling KW - Eco-routing KW - Marginal emission KW - Multi-scale dynamic network loading ER - TY - JOUR TI - Dose-Response Models are Conditional on Determination of Causality AU - Frey, H. Christopher T2 - RISK ANALYSIS AB - Risk AnalysisVolume 36, Issue 9 p. 1751-1754 Invited Commentaries Dose–Response Models are Conditional on Determination of Causality H. Christopher Frey, Corresponding Author H. Christopher Frey frey@ncsu.edu Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC, USA; frey@ncsu.edu.Search for more papers by this author H. Christopher Frey, Corresponding Author H. Christopher Frey frey@ncsu.edu Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC, USA; frey@ncsu.edu.Search for more papers by this author First published: 15 September 2016 https://doi.org/10.1111/risa.12672Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume36, Issue9Special Issue: Air Pollution Health RisksSeptember 2016Pages 1751-1754 This article also appears in:Air Pollution Health Risks RelatedInformation DA - 2016/9// PY - 2016/9// DO - 10.1111/risa.12672 VL - 36 IS - 9 SP - 1751-1754 SN - 1539-6924 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84992199746&partnerID=MN8TOARS ER - TY - JOUR TI - Woven Fabrics Containing Hybrid Yarns for Shielding Electromagnetic Radiation AU - Marciniak, Katarzyna AU - Grabowska, Katarzyna AU - Stempien, Zbigniew AU - Ciesielska-Wrobel, Izabela AU - Rutkowska, Aleksandra AU - Taranek, Dorota T2 - FIBRES & TEXTILES IN EASTERN EUROPE DA - 2016/// PY - 2016/// DO - 10.5604/12303666.1221744 VL - 24 IS - 6 SP - 109-115 SN - 1230-3666 KW - steel yarn KW - copper wire KW - hybrid yarn KW - woven fabric KW - electromagnetic interference KW - shielding efficiency ER - TY - CONF TI - Measured wave dispersion in tubes excited with acoustic radiation force matches theoretical guided wave dispersion AU - Urban, M. W. AU - Astaneh, A. V. AU - Aquino, W. AU - Greenleaf, J. F. AU - Guddati, M. N. AB - Acoustic radiation force (ARF) has been used to generate shear waves in many different tissues for the purpose of quantifying material properties of those tissues. This method has also been applied to arteries, but care must be taken in this application because waves produced in the arterial wall are guided waves. To obtain accurate measurements of mechanical properties of arteries, guided wave inversion can be used, where experimental wave dispersion is iteratively matched with theoretical dispersion curves. In this paper we study wave propagation in three sets of rubber tubes with different mechanical properties, and compare their measured and theoretical dispersion curves. Three sets of tubes were made with outer diameters of 8 mm and wall thicknesses of 1 mm to mimic an adult carotid artery. A different rubber mixture was used for each set of tubes, VytaFlex 10, VytaFlex20, and ReoFlex 30. Reference samples were also poured for testing with hyper-frequency viscoelastic spectroscopy (HFVS) instrument for measurement of the material complex modulus. Wave propagation measurements were made with a Verasonics system and linear array with water inside and surrounding the tubes. Acoustic radiation force was used to generate the waves with a 200 μs push at 4.1 MHz and plane wave imaging at a frame rate of 14.9 kHz was used for measuring the propagating waves. A two-dimensional Fourier transform method was used to extract the dispersion curves from the measured particle velocity. Theoretical dispersion curves for flexural modes with circumferential wavenumber n = 1, 2, 3 were calculated from the material properties measured with HFVS for comparison with the ultrasound-based results. The measured dispersion curve matches well with theoretical results. However, the match is not with a single theoretical dispersion curve, but with different theoretical curves at different frequencies. This new approach of matching with multiple theoretical curves can be used for better understanding of wave propagation in arterial walls and improved characterization of their mechanical properties. C2 - 2016/// C3 - 2016 ieee international ultrasonics symposium (ius) DA - 2016/// DO - 10.1109/ultsym.2016.7728821 ER - TY - JOUR TI - Three-Dimensional Electrical Impedance Tomography to Monitor Unsaturated Moisture Ingress in Cement-Based Materials AU - Smyl, Danny AU - Hallaji, Milad AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - TRANSPORT IN POROUS MEDIA AB - The development of tools to monitor unsaturated moisture flow in cement-based material is of great importance, as most degradation processes in cement-based materials take place in the presence of moisture. In this paper, the feasibility of electrical impedance tomography (EIT) to monitor three-dimensional (3D) moisture flow in mortar containing fine aggregates is investigated. In the experiments, EIT measurements are taken during moisture ingress in mortar, using electrodes attached on the outer surface of specimens. For EIT, the so-called difference imaging scheme is adopted to reconstruct the change of the 3D electrical conductivity distribution within a specimen caused by the ingress of water into mortar. To study the ability of EIT to detect differences in the rate of ingress, the experiment is performed using plain water and with water containing a viscosity-modifying agent yielding a slower flow rate. To corroborate EIT, X-ray computed tomography (CT) and simulations of unsaturated moisture flow are carried out. While X-ray CT shows contrast with respect to background only in highly saturated regions, EIT shows the conductivity change also in the regions of low degree of saturation. The results of EIT compare well with simulations of unsaturated moisture flow. Moreover, the EIT reconstructions show a clear difference between the cases of water without and with the viscosity-modifying agent and demonstrate the ability of EIT to distinguish between different flow rates. DA - 2016/10// PY - 2016/10// DO - 10.1007/s11242-016-0756-1 VL - 115 IS - 1 SP - 101-124 SN - 1573-1634 KW - Concrete KW - Electrical impedance tomography KW - Unsaturated moisture transport KW - Electrical methods KW - X-ray computed tomography ER - TY - JOUR TI - Temperature effects of linear amplitude sweep testing and analysis AU - Safaei, F. AU - Castorena, C. T2 - Transportation Research Record DA - 2016/// PY - 2016/// IS - 2574 SP - 92-100 ER - TY - JOUR TI - Simulation guidance for calibration of freeway lane closure capacity AU - Yeom, C. AU - Rouphail, N. M. AU - Rasdorf, W. AU - Schroeder, B. J. T2 - Transportation Research Record DA - 2016/// PY - 2016/// IS - 2553 SP - 82-89 ER - TY - JOUR TI - Modeling freeway work zones with mesoscopic dynamic traffic simulator validation, gaps, and guidance AU - Tanvir, S. AU - Karmakar, N. AU - Rouphail, N. M. AU - Schroeder, B. J. T2 - Transportation Research Record DA - 2016/// PY - 2016/// IS - 2567 SP - 122-130 ER - TY - JOUR TI - Exploring the association of rear-end crash propensity and micro-scale driver behavior AU - Kim, SangKey AU - Song, Tai-Jin AU - Rouphail, Nagui M. AU - Aghdashi, Seyedbehzad AU - Amaro, Ana AU - Goncalves, Goncalo T2 - SAFETY SCIENCE AB - The relationship between driver behavior at the tactical level and crash experience is a long sought association that has been elusive to explore. The availability of in-vehicle sensing devices capable of capturing and documenting micro-scale dynamic driver behavior offers the opportunity to begin such an exploration. This study integrates rear-end crash data experienced on a 63-mile section of I-40 in North Carolina over a four-year period with three months of micro-scale driving behavioral data gathered by an in-vehicle sensing system (i2D) that records and dispatches second by second vehicle dynamics data to a central database. The information collected by the i2D devices came from a fleet of about 20 vehicles driven by volunteers in their naturalistic driving environment. Additionally all crash and driver data were geo-located onto a link-based GIS environment. The objective of this study is to explore the association of crash propensity and micro-scale driving behavior. The initial findings of this research are promising. First, over 85% of all rear-end crashes occurred on 30 segments extending from 2000 feet upstream of an on-ramp to the on-ramp itself. Secondly, on those segments with high crash rates we have detected a high propensity of drivers to decelerate at high rates (4 m/s2 or more). We have also tested and confirmed that the sharp deceleration phenomenon is not confined to a few drivers, but appears to be common for the high-crash segments, using trip-based analyses. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.ssci.2016.05.016 VL - 89 SP - 45-54 SN - 1879-1042 KW - Rear end crashes KW - In-vehicle sensing KW - Driver behavior KW - Safety ER - TY - JOUR TI - Evaluation of compressive strength of concrete members laterally confined by various FRP composites and exposed to high temperatures AU - Jung, W. AU - Kwon, M. AU - Ju, B. T2 - KSCE Journal of Civil Engineering DA - 2016/// PY - 2016/// VL - 20 IS - 6 SP - 2410-2419 ER - TY - JOUR TI - Effect of Silo Storage Time on the Characteristics of Virgin and Reclaimed Asphalt Pavement Mixtures AU - Jacques, Christopher AU - Daniel, Jo Sias AU - Bennert, Thomas AU - Reinke, Gerald AU - Norouzi, Amirhossein AU - Ericson, Christopher AU - Mogawer, Walaa AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Many hot-mix asphalt plants store material in heated silos before it is ready to be transported to construction sites. The time that material is stored in the silo is not controlled and varies widely, depending on several factors. As the material is exposed to elevated temperatures, short-term aging of the binder may occur. Another important consideration is the interaction between reclaimed asphalt pavement (RAP) and virgin binders, as blending or diffusion could occur between the binders. In this study, a virgin and 25% RAP mixture were sampled at incremental silo storage times up to 10 h. Characterization testing included performance grading, rheological indexes, Glover–Rowe parameter evaluation, rolling thin film oven aging on the binders, complex modulus, a simplified viscoelastic continuum damage model (S-VECD) for fatigue, and thermal stress restrained specimen testing of the mixtures. Simulations that used layered viscoelastic critical distresses pavement analysis to predict fatigue behavior from the S-VECD model were used to show the potential effects of silo storage time on pavement life. Results from all tests indicated that mixtures aged with an increase in silo storage time. RAP materials experienced a greater effect; this effect may be a function of the air void content or indication of blending–diffusion in the silo. Rolling thin film oven aging showed that current laboratory conditioning methods do not necessarily simulate asphalt plant production. Production parameters, such as silo storage time, have a significant impact on mixture performance. DA - 2016/// PY - 2016/// DO - 10.3141/2573-10 IS - 2573 SP - 76-85 SN - 2169-4052 ER - TY - JOUR TI - Effect of Biodiesel Fuels on Real-World Emissions of Passenger Locomotives AU - Graver, Brandon M. AU - Frey, H. Christopher AU - Hu, Jiangchuan T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Few data are available regarding the effect of biodiesel on exhaust emission rates of two-stroke engines used in many passenger locomotives. Using a portable emissions measurement system (PEMS), duty cycle average nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and carbon dioxide (CO2) emission rates were measured for three locomotives operating on ultra-low sulfur diesel (ULSD) and soy-based B10, B20, and B40 biodiesel blends. Measurements were conducted in the rail yard (RY) and over-the-rail (OTR) during passenger service. Compared to ULSD, B20 biodiesel had statistically significant average emission rate reductions in the RY of 58% for CO, 45% for PM, and 6% CO2 and OTR of 59% for HC, 50% for CO, 26% for PM, and 5% for CO2. The average differences in NOx emission rates for both the RY and OTR, and HC in the RY, were not statistically significant. The OTR findings typically agreed qualitatively with the RY findings; however, OTR provides a better basis for estimating the real-world impact of fuel switching. The results indicate substantial potential to reduce in-use locomotive emissions for existing older locomotives, with the exception of NOx. DA - 2016/11/1/ PY - 2016/11/1/ DO - 10.1021/acs.est.6b03567 VL - 50 IS - 21 SP - 12030-12039 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84994320268&partnerID=MN8TOARS ER - TY - JOUR TI - Dynamic Bandwidth Analysis for Coordinated Arterial Streets AU - Kim, Sangkey AU - Hajbabaie, Ali AU - Williams, Billy M. AU - Rouphail, Nagui M. T2 - JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS AB - A commonly used strategy for improving mobility along signalized arterials is to coordinate neighboring intersections to minimize vehicle stops by maximizing the duration of green bands, otherwise known as arterial bandwidth. Signal coordination has been researched, developed, and refined for five decades. In lieu of traditional methods that are based on the analysis of programmed green times (which assume all phases operate at their maximum settings), a dynamic bandwidth analysis method is presented that reproduces actual dynamic bandwidth durations using closed loop signal data. The analysis is intended to help assess the performance of semi-actuated coordinated signal systems on arterial streets. In addition, the study highlights the arterial progression benefits that result from changing coordinated intersection offsets based on optimizing the dynamic, rather than the programmed, bandwidths. Detailed analysis at three arterial sites revealed that coordinated green phase time distributions are complex and multimodal and cannot be represented by a single-valued statistic. Dynamic bandwidth analysis confirmed that programmed green bandwidth consistently underestimates the size of the actual dynamic bandwidth, and exhaustive search results highlighted the potential for further improvements in coordination. Future research will include field and simulation comparative studies and the development of efficient methods for dynamic bandwidth optimization. DA - 2016/// PY - 2016/// DO - 10.1080/15472450.2015.1074575 VL - 20 IS - 3 SP - 294-310 SN - 1547-2442 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84941243905&partnerID=MN8TOARS ER - TY - JOUR TI - Do mechanical and environmental loading have a synergistic effect on the degradation of pultruded glass fiber reinforced polymers? AU - Pour-Ghaz, Mohammad AU - Miller, Bryant L. H. AU - Alla, Omar Khalaf AU - Rizkalla, Sami T2 - COMPOSITES PART B-ENGINEERING AB - This paper investigates the effect of simultaneous mechanical and environmental loading on the degradation rate of pultruded Glass Fiber Reinforced Polymer (GFRP) composites. The experimental program included testing a large number of GFRP coupons, with vinylester or polyester matrices, conditioned for 1000 or 2000 h under a wide range of sustained stresses and exposed to freshwater or saltwater at an elevated temperature of 60 °C. Mechanical tests, including tensile strength and elastic modulus measurements were performed on the GFRP composites. In addition, glass transition measurements, moisture uptake measurements, scanning electron microscopy, and acoustic emission testing were performed to better understand the synergistic effect of mechanical loading and environmental conditions. DA - 2016/12/1/ PY - 2016/12/1/ DO - 10.1016/j.compositesb.2016.09.007 VL - 106 SP - 344-355 SN - 1879-1069 KW - Acoustic emission KW - Durability KW - Fiber reinforced polymer KW - GFRP KW - Glass transition ER - TY - JOUR TI - Development of a statistical analysis model to benchmark the energy use intensity of subway stations AU - Ahn, Jonghoon AU - Cho, Soolyeon AU - Chung, Dae Hun T2 - APPLIED ENERGY AB - This paper presents an Energy Use Intensity (EUI) indicator model for energy benchmarking subway stations. Among the mass transportation systems, a subway, in terms of its rapidity, punctuality, and efficiency, has been preferred in metropolitan area and recently spotlighted as it mitigates environmental impacts to global warming. Of its several advantages, a subway’s carbon footprint is negligible, which directly contributes to energy savings. Therefore, demands of subway systems have increased. However, subway stations have rarely been included in most energy performance studies and surveys. Due to a lack of information and design complexity, most designers are not able to do optimal design practices. A statistical model was developed in this study using the benchmark process for 157 actual subway stations in Seoul, South Korea. It includes measured data, utility bills, simulation results, and regression modeling. This adjusted EUI benchmark model was developed using characteristics of subway stations and a statistical validation process. The effectiveness of the model is tested and verified by comparing between measured EUI and adjusted normalized EUI (EUInorm) of actual subway stations. This paper includes the test results of EUI indicator model to benchmark energy performance and assesses existing subway station. DA - 2016/10/1/ PY - 2016/10/1/ DO - 10.1016/j.apenergy.2016.06.065 VL - 179 SP - 488-496 SN - 1872-9118 KW - Subway stations KW - Underground KW - Energy performance benchmark KW - Measured and simulated data KW - Statistical validation KW - Regression model ER - TY - JOUR TI - Climate change impacts in the energy supply of the Brazilian hydro-dominant power system AU - Queiroz, Anderson Rodrigo AU - Marangon Lima, Luana M. AU - Marangon Lima, Jose W. AU - Silva, Benedito C. AU - Scianni, Luciana A. T2 - RENEWABLE ENERGY AB - Over the past few years, there has been a growing global consensus related to the importance of renewable energy to minimize the emission of greenhouse gases. The solution is an increase in the number of renewable power plants but unfortunately, this leads to a high dependence on climate variables which are already affected by climate change. Brazil is one of the largest producers of electricity by renewables through its hydro-dominant power generation system. However, hydro-generation depends on water inflows that are directly affected by climate change that consequently affect the electricity production. Therefore, these changes need to be considered in the operation and planning of a hydro-dominant power system. In this paper, we present the effects of different climate scenarios in the water inflows produced by the regional Eta climate model. Normally, studies use an optimization model to make decisions in case of a hydro-thermal scheduling problem and use the assured energy to evaluate the hydro-production. In this analysis, water inflows used in the optimization process consider different trends according to its associated climate scenario. Our paper shows that climate change may drastically impact the system assured energy and consequently, the system's capability to supply load. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.renene.2016.07.022 VL - 99 SP - 379-389 SN - 1879-0682 UR - https://doi.org/10.1016/j.renene.2016.07.022 KW - Renewable generation KW - Multi-stage stochastic optimization KW - Climate change effects KW - Hydro-thermal scheduling KW - Water inflows ER - TY - JOUR TI - Characterization of municipal solid waste collection operations AU - Jaunich, Megan K. AU - Levis, James W. AU - DeCarolis, Joseph F. AU - Gaston, Eliana V. AU - Barlaz, Morton A. AU - Bartelt-Hunt, Shannon L. AU - Jones, Elizabeth G. AU - Hauser, Lauren AU - Jaikumar, Rohit T2 - Resources, Conservation and Recycling AB - Solid waste collection contributes to the cost, emissions, and fossil fuel required to manage municipal solid waste. Mechanistic models to estimate these parameters are necessary to perform integrated assessments of solid waste management alternatives using a life-cycle approach; however, models are only as good as their parameterization. This study presents operational waste collection data that can be used in life-cycle models for areas with similar collection systems, and provides illustrative results from a collection process model using operational data. Fuel use and times associated with various aspects of waste collection were obtained for vehicles collecting mixed residential (residual) waste, recyclables, and yard waste from single-family residences in selected municipalities. The total average fuel economy for similarly-sized diesel collection vehicles was 0.6-1.4 km/L (1.4–3.3 mpg (miles per gallon)) for residual waste and 0.8–1 km/L (1.9–2.4 mpg) for recyclables. For residual waste and recyclables collection stops, the average time to collect at each residence using automated collection was 11–12 s and 13–17 s, respectively. The average time between stops was 11–12 s and 10–13 for residuals and recyclables, respectively. A single yard waste route was observed, and all collection times were longer than those measured for either recycling or residual waste. Unload or tip times were obtained or measured at a landfill, transfer station, and material recovery facility (MRF). Average time to unload was 7–9 min at a MRF, 14–22 min at a landfill, and 11 min at a transfer station. Commercial and multi-family collection vehicles tend to have longer stops and spend more time between stops than single-family collection, and a larger portion of fuel is used while driving relative to single-family collection. Roll-off vehicles, which collect more waste per stop, spend longer at each stop and drive longer distances between stops than front-loader vehicles. Diesel roll-offs averaged 2.4 km/L (5.7 mpg) and front-loaders averaged 1.4 km/L (3.3 mpg). DA - 2016/11// PY - 2016/11// DO - 10.1016/j.resconrec.2016.07.012 VL - 114 SP - 92-102 J2 - Resources, Conservation and Recycling LA - en OP - SN - 0921-3449 UR - http://dx.doi.org/10.1016/j.resconrec.2016.07.012 DB - Crossref KW - Collection KW - Municipal solid waste KW - Collection fuel efficiency KW - Collection distance KW - Collection time ER - TY - JOUR TI - Blending Measurements in Mixtures with Reclaimed Asphalt Use of Scanning Electron Microscopy with X-Ray Analysis AU - Castorena, Cassie AU - Pape, Sonja AU - Mooney, Charles T2 - TRANSPORTATION RESEARCH RECORD AB - A major impediment to the widespread use of asphalt concrete with a high content of reclaimed asphalt pavement (RAP) is uncertainty in the degree of blending between the RAP and the fresh binder. Furthering knowledge concerning the blending between RAP and fresh binder has been difficult because of the lack of an experimental method to quantify the degree of blending in asphalt concrete. This study introduces energy dispersive X-ray spectroscopy (EDS) scanning electron microscopy (SEM) as a means to analyze the degree of blending between RAP and fresh materials in asphalt concrete. EDS allows for mapping the distribution and relative proportion of elements in a sample, hence, allowing for the detection of the distribution of elements in an asphalt concrete specimen. Fresh and RAP binders will have a similar elemental composition. Therefore, titanium dioxide in a fine powder form (0.15-µm particles) is blended with the fresh binder as a tracer before the production of asphalt concrete to enable delineation of the RAP and fresh binders using EDS SEM. The efficacy of EDS SEM for quantifying the degree of blending between RAP and fresh binders in asphalt concrete is demonstrated with two high RAP content mixtures. DA - 2016/// PY - 2016/// DO - 10.3141/2574-06 IS - 2574 SP - 57-63 SN - 2169-4052 ER - TY - JOUR TI - Verification of Time-Temperature Superposition Principle for Shear Bond Failure of Interlayers in Asphalt Pavements AU - Cho, Seong-Hwan AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Asphalt pavement structures are composed of different asphalt concrete layers with surface layers that are bonded together with a tack coat. Thus, interlayer bonding between pavement layers is a key factor that affects the performance of any pavement structure. However, relatively little attention has been given to the characterization and modeling of interlayer bonding or to associated test methods that can be used in the laboratory to evaluate the bond strength between asphalt concrete layers. This paper presents a test method for evaluating interface bonding between asphalt concrete layers in shear mode. Moreover, the time–temperature superposition (t-TS) principle with growing damage in shear failure mode is examined to characterize the shear bond strength of asphalt concrete pavements for a wide range of temperatures. The subsequent validation of the t-TS principle allows the shear bond strength between asphalt layers at various temperatures and loading rates to be determined with only three or four shear tests. Comparison of the shear stress values calculated from a mechanistic pavement analysis program for a critical condition with the shear strength values at the condition determined from the prediction model developed in this study can provide the foundation for a mechanistic design to prevent shear bond failure between asphalt layers. DA - 2016/// PY - 2016/// DO - 10.3141/2590-03 IS - 2590 SP - 18-27 SN - 2169-4052 ER - TY - CONF TI - The use of four-point bending notched beam fatigue tests to rank crack-mitigating interlayers AU - Wargo, A. D. AU - Safavizadeh, S. AU - Kim, R. Y. C2 - 2016/// C3 - 8th rilem international symposium on testing and characterization of sustainable and innovative bituminous materials DA - 2016/// VL - 11 SP - 359-370 ER - TY - JOUR TI - Strain Limit States for Circular RC Bridge Columns AU - Goodnight, Jason C. AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - EARTHQUAKE SPECTRA AB - Described in this paper are strain limit states for reinforced concrete bridge columns. A total of 30 large scale reinforced concrete bridge columns were subjected to either reversed cyclic loading or real seismic load histories as part of this research program. Through the use of a non-contact three-dimensional (3-D) position measurement system, accurate strain measurements that are not possible with conventional instrumentation were made, which allowed for development of strain limits for serviceability, spiral yielding, and reinforcing bar buckling limit states. The proposed bar buckling strain limit was compared to an existing drift-based approach and one formulated using finite element analysis for columns in the data set and the literature. DA - 2016/8// PY - 2016/8// DO - 10.1193/030315eqs036m VL - 32 IS - 3 SP - 1627-1652 SN - 1944-8201 ER - TY - CONF TI - Seismic qualification of equipment: A pra-consistent framework AU - Chatterjee, P. AU - Gupta, A. AB - The seismic probabilistic risk assessment (SPRA) for a nuclear power plant involves the estimation of fragility curves for plant equipment. The seismic qualification of an equipment based on testing requires the equipment to continue to function when subjected to a specific test response spectrum (TRS). Broad banded ground motions have been found to cause more damage to equipment than the filtered narrow banded excitations. As a result, the definition of acceleration capacity used in the fragility models use clipped response spectra for both test response spectrum (TRS) and required response spectrum (RRS). The main purpose of the clipping factors is to convert a narrow banded response spectrum to a broad banded spectrum. The broadband correction factor and the modal interaction correction factors together contribute to the definition of clipping factor. The current study involves reconciliation with previous research by generating the mean response factor for different waveforms and subsequently the root-mean-square (RMS) severity ratio as a function of bandwidth. This ratio can be estimated for real earthquakes from their peak-to-rms values and the peak spectral values. In addition it can be shown that in case of real narrow banded earthquakes, this ratio is even lower and therefore the clipping would be greater. The modal interaction correction factor which considers the effect of interaction between different modes in case of broad banded time histories has also been investigated. The primary objective of this work is to study the existing Conservative Deterministic Failure Margin (CDFM) and Probabilistic approaches for estimating these factors as per the guidelines of EPRI [2] and apply the same to real life ground motions. It has been observed that the recommended practices are based on studying the behavior of random ground motions generated artificially for different bandwidths and center frequencies. The present study aims towards a more realistic fragility estimation of equipment by studying the spectral response of equipment based on actual ground motions. The purpose is to evaluate clipping factors that are consistent with Seismic Probabilistic Risk Assessment. C2 - 2016/// C3 - Proceedings of the 24th International Conference on Nuclear Engineering, 2016, vol 1 DA - 2016/// DO - 10.1115/icone24-60674 ER - TY - JOUR TI - Seismic Enhancement of Welded Unreinforced Flange-Bolted Web Steel Moment Connections AU - Morrison, Machel Leigh AU - Schweizer, Douglas Quinn AU - Hassan, Tasnim T2 - JOURNAL OF STRUCTURAL ENGINEERING AB - Widespread damage to welded unreinforced flange-bolted web (WUF-B) steel moment connections during the 1994 Northridge earthquake led to intensive research study of this connection. Despite the improvements to weld metal and connection details, the post-Northridge WUF-B connection was unable to attain sufficient ductility for use in special moment frames (SMFs). This study presents detailed finite element (FE) analysis of post-Northridge WUF-B connections to better understand the mechanisms which limited connection ductility in laboratory tests. Observations made from the FE analysis led to the development and numerical study of a modified WUF-B connection that combines a new bolted web design with a recently validated technique to promote plastic hinging of the beam away from the connection joint. The proposed connection provides the benefit of reduced field welding and UT inspection without sacrificing connection ductility and seismic performance. Finally, the proposed connection is experimentally validated through full-scale seismic testing. The pilot test specimen exceeded the AISC 341 qualifying 4% interstory drift angle without significant strength loss. No weld or near-weld cracks were observed. Instead, failure of the connection resulted from large local buckling deformation in the plastic hinge away from the welded joint. DA - 2016/11// PY - 2016/11// DO - 10.1061/(asce)st.1943-541x.0001575 VL - 142 IS - 11 SP - SN - 1943-541X KW - Steel moment connection KW - Seismic performance enhancement KW - Beam plastic hinge KW - Heat-treated beam section KW - Reduced beam section KW - Modified WUF-B KW - Metal and composite structures ER - TY - JOUR TI - Role of Safety Training: Impact on Hazard Recognition and Safety Risk Perception AU - Namian, Mostafa AU - Albert, Alex AU - Zuluaga, Carlos M. AU - Behm, Michael T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Hazard recognition and the accurate perception of safety risk are fundamental to the success of any safety program. When hazards remain unrecognized, or the associated safety risk is underestimated, the likelihood of catastrophic and unexpected injuries dramatically increase. Unfortunately, recent research has found that a large number of hazards in construction remain unrecognized. Likewise, past studies have demonstrated that safety risk is widely underestimated within construction. To improve hazard recognition and the accurate perception of safety risk, employers adopt a wide variety of training programs. However, the prevalent use of ineffective and unengaging training methods have significantly impeded training efforts in construction. The purpose of this research was to assess the impact of safety training on two objective training outcomes: hazard recognition performance and safety risk perception. The research objectives were accomplished by gathering empirical data from 51 active projects in the United States. Specifically, data pertaining to the training method (i.e., high-engagement versus low-engagement training) adopted at the project level were gathered, following which the hazard recognition ability of representative workers and their safety risk perception levels were measured. The results of the study revealed that (1) compared to low-engagement training, high-engagement training is associated with higher levels of hazard recognition and safety risk perception; and (2) the effect of training on safety risk perception is mediated by hazard recognition performance. Therefore, workers representing projects that offered high-engagement training were able to identify a larger proportion of hazards, and consequently perceived that safety risk was relatively higher. The findings of this study will be useful to practicing professionals seeking to improve training delivery, hazard recognition performance, and the perception of safety risk within construction. This study represents the first formal attempt to empirically evaluate the holistic relationship between training, hazard recognition, and safety risk perception in the construction context. DA - 2016/12// PY - 2016/12// DO - 10.1061/(asce)co.1943-7862.0001198 VL - 142 IS - 12 SP - SN - 1943-7862 KW - Construction safety KW - Safety training KW - Safety management KW - Hazard identification KW - Hazard recognition KW - Risk assessment KW - Risk perception KW - Training delivery KW - Training method KW - Labor and personnel issues ER - TY - JOUR TI - Resilient welded steel moment connections by enhanced beam buckling resistance AU - Morrison, Machel L. AU - Hassan, Tasnim T2 - JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH AB - This study develops two (2) simple but effective techniques for enhancing buckling resistance of welded steel moment connections (WSMCs). The ANSI/AISC 358-10 prequalified connections satisfy the 4% interstory drift requirement, however experimental studies have shown that their strength degradation may initiate as early as 3% drift. This strength degradation has been observed to be initiated by buckling of the beam web which is followed by buckling of the beam flange and twisting of the beam. Consequently, buildings with the prequalified connections may sustain significant buckling damages under severe earthquakes and it is questionable as to whether these connections are capable of resisting gravity loads or lateral loads from strong aftershocks following a severe earthquake. To improve upon these shortcomings, two (2) performance enhancing techniques are proposed and investigated through finite element analysis (FEA). The more promising of the two involves reinforcing the beam web in the expected plastic hinge with a web reinforcement plate. Finite element analysis demonstrated that this reinforcement enhances the beam buckling resistance of WSMCs and thereby significantly reduces the beam buckling damages even at 5% interstory drift. The potential of this technique is analytically and experimentally demonstrated for the recently developed heat-treated beam section (HBS) WSMC. Test results confirm that the web reinforcement plate was effective in reducing local buckling damage and associated strength degradation, thereby improving the performance of HBS WSMCs. Areas for application and future development of the proposed techniques are identified. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.jcsr.2016.07.012 VL - 127 SP - 77-91 SN - 1873-5983 KW - Steel moment connection KW - Seismic performance enhancement KW - Beam plastic hinge KW - Heat-treated beam section KW - Web reinforcement ER - TY - JOUR TI - Reshaping energy policy for sustainable development: Curbing Iran's carbon emission monster via renewable energies AU - Eshraghi, Hadi AU - Maleki, Abbas T2 - ENERGY SOURCES PART B-ECONOMICS PLANNING AND POLICY AB - This paper formulates flow of energy from primary resources and import routes to different socio-economic sectors by making use of Long-Range Energy Alternatives Planning (LEAP) model. It presents a baseline of how Iran’s future production and consumption patterns evolve. It also seeks plausible scenario for renewable energies utilization and evaluates its mitigation potential and economic aspects. Model results indicate that exploitation of a “not-too-strict” package of renewable sources featuring 10 GW of wind and 19 GW of hydro by the end of 2035 will lead to CO2 emissions to be reduced up to an amount of 190.7 million tons in the study period. By accounting for the opportunity costs different fossil fuels can have, and with a 22% discount rate, abatement of 1 ton of CO2 costs about 7.5 $ (in 2005 constant prices) that declines to zero with a discount rate equal to 7.7%. The paper is concluded by discussing policy options for overcoming barriers hindering the development of renewable resources in the context of country-specific characteristics. DA - 2016/// PY - 2016/// DO - 10.1080/15567249.2013.810313 VL - 11 IS - 9 SP - 830-840 SN - 1556-7257 KW - Climate change mitigation KW - energy policy KW - emission factor KW - LEAP model KW - renewable energy ER - TY - JOUR TI - Modified Plastic-Hinge Method for Circular RC Bridge Columns AU - Goodnight, Jason C. AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - Journal of Structural Engineering AB - This paper discusses a research program aimed at defining accurate limit-state displacements that relate to specific levels of damage in reinforced concrete bridge columns subjected to seismic hazards. In design, concrete compressive and steel tensile strain limits are related to column deformations through the use of an equivalent curvature distribution. An experimental study was carried out to assess the performance of 30 circular well-confined bridge columns. Material strains, cross-section curvatures, and fixed-end rotations attributed to strain penetration of reinforcement into the adjoining member were quantified by using a three-dimesional (3D) position monitoring system. An equivalent curvature distribution was created that reflects the measured spread of plasticity and components of deformation. When compared with the current approach, the proposed modified plastic-hinge method improved the accuracy of both tensile and compressive strain-displacement predictions, while maintaining similar levels of accuracy for elastic displacements. These recommendations, combined with material strain limits defined in the larger research program, serve as input into a displacement-based design procedure to achieve a defined level of performance under a specific seismic hazard. DA - 2016/11// PY - 2016/11// DO - 10.1061/(asce)st.1943-541x.0001570 VL - 142 IS - 11 SP - 04016103 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001570 DB - Crossref KW - Concrete and masonry structures ER - TY - JOUR TI - Innovative Method for Remotely Fine-Tuning Offsets Along a Diverging Diamond Interchange Corridor AU - Kim, SangKey AU - Warchol, Shannon AU - Schroeder, Bastian J. AU - Cunningham, Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - Diverging diamond interchanges (DDIs) are relatively new in the United States, and signal coordination between the crossovers and adjacent intersections is challenging. This paper provides a method for remotely fine-tuning offsets for a DDI and its adjacent intersections. The proposed method uses the dynamic bandwidth analysis tool (DBAT). The tool uses actuated phase times from the signal controller to optimize the dynamic bandwidth on the basis of that entry data set. Four performance measures evaluated the proposed method: delay, stop severity index, maximum queue, and vehicle trajectory plots. The test results confirmed that DBAT provided a better offset solution than other bandwidth optimization tools that generally optimized programmed bandwidth only and did not account for early return to green caused by skipped or gapped-out movements. Under the DBAT offsets, delay for the through movements on the corridor decreased by 52.8% for northbound vehicles and 46.83% for southbound vehicles. The average delay reduction over all measured paths for uncongested and congested scenarios was 13.88% and 3.50%, respectively. The proposed method and workflow can significantly reduce the offset retiming work process. Normally, this manual process takes more than a day, but the proposed method can be completed in less than an hour without visiting the study site. Furthermore, the proposed method can coordinate any set of movements, as well as multiple travel paths. The authors believe that the proposed method and workflow will significantly help both retiming and new timing of arterial signal coordination along DDI corridors and other signal systems. DA - 2016/// PY - 2016/// DO - 10.3141/2557-04 IS - 2557 SP - 33-43 SN - 2169-4052 ER - TY - JOUR TI - Impact of exit ramp geometric treatments at diverging diamond interchanges on queue spillback AU - Warchol, S. AU - Schroeder, B. J. AU - Cunningham, C. T2 - Transportation Research Record DA - 2016/// PY - 2016/// IS - 2556 SP - 75-85 ER - TY - JOUR TI - Hardwiring microbes via direct interspecies electron transfer: mechanisms and applications AU - Cheng, Qiwen AU - Call, Douglas F. T2 - ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS AB - Direct interspecies electron transfer (DIET) has important implications for the design and operation of biological treatment processes. DA - 2016/8/1/ PY - 2016/8/1/ DO - 10.1039/c6em00219f VL - 18 IS - 8 SP - 968-980 SN - 2050-7895 ER - TY - JOUR TI - Framework for Defining Asset Features to Monitor and Assess Earth-Retaining Structures AU - Rasdorf, William AU - Butler, Cedrick J. AU - Findley, Daniel J. AU - Gabr, Mohammed A. AU - Bert, Steven A. T2 - TRANSPORTATION RESEARCH RECORD AB - Permanent earth-retaining structures (ERSs), including retaining walls, have been systematically managed, inventoried, and assessed by several government organizations, including the City of Cincinnati, Ohio; the Oregon and Pennsylvania Departments of Transportation; and the Central Federal Lands Highway Division of FHWA (for the National Park Service). For a comprehensive ERS asset management program, a careful evaluation of the structural health, criticality, and risk of ERSs is essential for proper management (preservation, rehabilitation, or replacement) of these aging assets. However, many transportation agencies struggle with the evaluation and incorporation of risk in their ERS management programs. This study addressed the development of a framework that would evaluate risk and would define its relationship to ERS condition (likelihood of failure) and ERS criticality (consequence of failure). A methodology for relating risk to routine inspection cycles for ERSs and remedial actions for those in distress is proposed. DA - 2016/// PY - 2016/// DO - 10.3141/2579-02 VL - 2579 IS - 2579 SP - 8-16 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014465205&partnerID=MN8TOARS ER - TY - CONF TI - Fragility of a flood defense structure subjected to multi-hazard scenario AU - Bodda, S. S. AU - Sandhu, H. K. AU - Gupta, A. AB - The March 2011 Fukushima Daiichi nuclear power plant disaster has highlighted the significance of maintaining the integrity of flood protection systems in the vicinity of a nuclear power plant. In the US, Oyster Creek nuclear plant was shut down when high storm surge during hurricane Sandy threatened its water intake and circulation systems. A gravity dam located upstream of a power plant can undergo seismic failure or flooding failure leading to flooding at the nuclear plant. In this paper, we present the results from a study on evaluating the fragilities for failure of a concrete gravity dam under both the flooding and the seismic events. Finite element analysis is used for modeling the seismic behavior as well as the seepage through foundation. A time-dependent analysis is considered to account for appropriate nonlinearities. Failure of dam foundation is characterized by rupture, and the failure of dam body is characterized by excessive deformation for the flooding and seismic loads respectively. The study presented in this paper has focused on a concrete gravity dam because of the need of validation of models which exist in prior studies only for concrete gravity dams. However, the concepts are directly applicable to any concrete flood defense structure. C2 - 2016/// C3 - Proceedings of the 24th International Conference on Nuclear Engineering, 2016, vol 4 DA - 2016/// DO - 10.1115/icone24-60508 ER - TY - JOUR TI - Field experiment for exploring the effects of in-vehicle warning information on driver's responsive behaviour AU - Song, T. J. AU - Park, S. AU - Oh, C. T2 - Journal of Engineering-JOE DA - 2016/// PY - 2016/// ER - TY - JOUR TI - Exponential convergence through linear finite element discretization of stratified subdomains AU - Guddati, Murthy N. AU - Druskin, Vladimir AU - Astaneh, Ali Vaziri T2 - JOURNAL OF COMPUTATIONAL PHYSICS AB - Motivated by problems where the response is needed at select localized regions in a large computational domain, we devise a novel finite element discretization that results in exponential convergence at pre-selected points. The key features of the discretization are (a) use of midpoint integration to evaluate the contribution matrices, and (b) an unconventional mapping of the mesh into complex space. Named complex-length finite element method (CFEM), the technique is linked to Padé approximants that provide exponential convergence of the Dirichlet-to-Neumann maps and thus the solution at specified points in the domain. Exponential convergence facilitates drastic reduction in the number of elements. This, combined with sparse computation associated with linear finite elements, results in significant reduction in the computational cost. The paper presents the basic ideas of the method as well as illustration of its effectiveness for a variety of problems involving Laplace, Helmholtz and elastodynamics equations. DA - 2016/10/1/ PY - 2016/10/1/ DO - 10.1016/j.jcp.2016.06.045 VL - 322 SP - 429-447 SN - 1090-2716 KW - Optimal grids KW - Pade approximants KW - Dirichlet-to-Neumann maps KW - Rational approximation KW - Spectral element methods ER - TY - JOUR TI - Environmental Comparison of Biochar and Activated Carbon for Tertiary Wastewater Treatment AU - Thompson, Kyle A. AU - Shimabuku, Kyle K. AU - Kearns, Joshua P. AU - Knappe, Detlef R. U. AU - Summers, R. Scott AU - Cook, Sherri M. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Micropollutants in wastewater present environmental and human health challenges. Powdered activated carbon (PAC) can effectively remove organic micropollutants, but PAC production is energy intensive and expensive. Biochar adsorbents can cost less and sequester carbon; however, net benefits depend on biochar production conditions and treatment capabilities. Here, life cycle assessment was used to compare 10 environmental impacts from the production and use of wood biochar, biosolids biochar, and coal-derived PAC to remove sulfamethoxazole from wastewater. Moderate capacity wood biochar had environmental benefits in four categories (smog, global warming, respiratory effects, noncarcinogenics) linked to energy recovery and carbon sequestration, and environmental impacts worse than PAC in two categories (eutrophication, carcinogenics). Low capacity wood biochar had even larger benefits for global warming, respiratory effects, and noncarcinogenics, but exhibited worse impacts than PAC in five categories due to larger biochar dose requirements to reach the treatment objective. Biosolids biochar had the worst relative environmental performance due to energy use for biosolids drying and the need for supplemental adsorbent. Overall, moderate capacity wood biochar is an environmentally superior alternative to coal-based PAC for micropollutant removal from wastewater, and its use can offset a wastewater facility's carbon footprint. DA - 2016/10/18/ PY - 2016/10/18/ DO - 10.1021/acs.est.6b03239 VL - 50 IS - 20 SP - 11253-11262 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84991829573&partnerID=MN8TOARS ER - TY - JOUR TI - Effect of Rejuvenator on Performance Properties of WMA Mixtures with High RAP Content AU - Sabouri, Mohammadreza AU - Choi, Yeong-Tae AU - Wang, Yizhuang AU - Hwang, Sungdo AU - Baek, Cheolmin AU - Kim, Richard Y. T2 - 8TH RILEM INTERNATIONAL SYMPOSIUM ON TESTING AND CHARACTERIZATION OF SUSTAINABLE AND INNOVATIVE BITUMINOUS MATERIALS AB - The production of warm mix asphalt (WMA) mixtures with high percentages of reclaimed asphalt pavement (RAP) is gaining attention as a way to save costs and efficiently utilize existing resources. However, WMA must perform at least as well as hot mix asphalt (HMA) before it can be used as a replacement for HMA. In this study, the performance of a WMA mixture with a high percentage of RAP (40 % RAP) and a WMA additive (1.5 % of binder weight) that works as a rejuvenator was evaluated and compared with the performance of a HMA mixture with the same amount of RAP in order to evaluate the effects of the WMA rejuvenator. These mixtures were evaluated in terms of fatigue cracking using the simplified viscoelastic continuum damage (S-VECD) model and in terms of rutting using the triaxial stress sweep (TSS) test. In addition, layered viscoelastic pavement analysis for critical distresses (LVECD) was used to predict the fatigue resistance of these mixtures for future use. The WMA rejuvenator was found to improve the mixing and compaction ability of the WMA mixture. Also, compared to the HMA mixture, the WMA mixture showed better fatigue resistance, but the rejuvenator found to have an adverse effect on the rutting resistance of the mixture. DA - 2016/// PY - 2016/// DO - 10.1007/978-94-017-7342-3_38 VL - 11 SP - 473-484 SN - 2211-0852 KW - Reclaimed asphalt pavement (RAP) KW - Warm mix asphalt (WMA) KW - Fatigue cracking KW - Rutting KW - Rejuvenator ER - TY - JOUR TI - Comparison of Fatigue Cracking Performance of Asphalt Pavements Predicted by Pavement ME and LVECD Programs AU - Wang, Yizhuang AU - Norouzi, Amirhossein AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Mechanistic–empirical pavement design has received significant attention from the pavement community as the method for designing asphalt pavements in the future. Currently available software for mechanistic–empirical pavement design includes the AASHTOWare Pavement ME Design (Pavement ME) program. The Pavement ME program allows users to predict pavement distresses by applying layered elastic theory for the mechanical responses and using empirical models for the distress predictions. The layered viscoelastic pavement design for critical distresses (LVECD) program, which employs three-dimensional viscoelastic finite element analysis with moving loads, can also be used to predict the fatigue and rutting performance of pavements. The LVECD program employs the simplified viscoelastic continuum damage (S-VECD) model as the material model for the fatigue performance predictions of asphalt mixtures under complex loading and environmental conditions. This paper examines and compares the performance of 33 pavement sections from five research projects located in the United States, Canada, and South Korea by using both the Pavement ME and LVECD computer programs. To verify the results obtained from these two programs, the simulations were compared with the field performance data. In terms of ranking, the LVECD simulations provided better agreement with the field performance data than did the Pavement ME simulations. One of the main reasons for the better predictions obtained by the LVECD program is that its fatigue performance predictions depend on the mixture properties of all the layers, whereas the Pavement ME program considers the fatigue properties of only the bottom layer mixture. DA - 2016/// PY - 2016/// DO - 10.3141/2590-06 IS - 2590 SP - 44-55 SN - 2169-4052 ER - TY - CONF TI - Bayesian network technique in probabilistic risk assessment for multiple hazards AU - Kwag, S. AU - Gupta, A. C2 - 2016/// C3 - Proceedings of the 24th International Conference on Nuclear Engineering, 2016, vol 4 DA - 2016/// ER - TY - CONF TI - A novel hybrid heating method for elevated temperature mechanical testing of miniature specimens AU - Li, L. AU - Ngaile, G. AU - Hassan, T. AB - The lack of robust testing systems to generate uniform elevated temperatures on specimens in material tests is hindering the advancement of small specimen testing technology (SSTT). The purpose of this study is to develop a novel hybrid heating method combining coil heating and electric-resistance specimen heating to uniformly heat micro specimens in material tests. In a hybrid heating process, two heating coils are used to heat the local temperatures on the specimen ends, and electric current is conducted through the specimen to generate Joule heat and compensate the heat transfer effects of natural convection and radiation around the specimen center area. In this way, a highly uniform temperature distribution can be generated on the specimen between the heating coils. In this study, Thermal-Electrical and Transient Thermal FEA simulations are applied to analyze the temperature distributions and preheating times on the micro specimens under coil heating, electric-resistance specimen heating, and hybrid heating respectively. According to the simulation results, it can be concluded that hybrid heating method can provide the ability to generate highly uniform elevated temperature conditions on different micro tubular specimens with short preheating times. C2 - 2016/// C3 - Proceedings of the ASME 11th International Manufacturing Science and Engineering Conference, 2016, vol 1 DA - 2016/// DO - 10.1115/msec2016-8852 ER - TY - JOUR TI - Wearable thermoelectric generators for human body heat harvesting AU - Hyland, Melissa AU - Hunter, Haywood AU - Liu, Jie AU - Veety, Elena AU - Vashaee, Daryoosh T2 - APPLIED ENERGY AB - A thermoelectric generator (TEG) can be used to harvest electrical energy from human body heat for the purpose of powering wearable electronics. At the NSF Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), TEGs are one of the enabling technologies being explored to advance the center’s mission of creating wearable, self-powered, health and environmental monitoring systems. As part of this effort, an exploration of the relevant parameters for maximizing the wearable TEG power output from the body heat and maintaining the body comfort is particularly important. For this purpose, the heat from the body must be directed into TEG with minimal loss, the generator must be designed for maintaining a high temperature differential across the thermoelectric material, and the generator must have a small form factor to maintain the body comfort. In order to address these requirements, an optimum TEG design was developed and experiments were conducted both on a temperature-controlled hot plate and on different body locations including the wrist, upper arm, and chest. The TEG was further fabricated into a T-shirt and the power was recorded for different human activities. Comparison of the experiments on various body locations and on the T-shirt yielded the highest to lowest power generated on the upper arm, wrist, chest and T-shirt, respectively. The prospect of powering a wearable electrocardiogram sensor by a TEG on the upper arm is discussed. DA - 2016/11/15/ PY - 2016/11/15/ DO - 10.1016/j.apenergy.2016.08.150 VL - 182 SP - 518-524 SN - 1872-9118 KW - Thermoelectric generators KW - Body heat harvesting KW - Wearable electronics ER - TY - JOUR TI - The nonlinear behavior of threaded piping connections: Application using a modified Ramberg-Osgood model AU - Ryu, Yonghee AU - Matzen, Vernon C. T2 - OCEAN ENGINEERING AB - Damage to nonstructural components such as piping systems and mechanical and electrical equipment can result in major economic loss, injuries, and loss of life in critical facilities like offshore structures, nuclear power plants, and hospitals. Failures in piping systems especially due to water leakage can lead to shut-down of a facility, and connections in the pipelines are particularly important since failures often occur at these locations. This paper presents a technique for modeling threaded connections as rotational springs, either linear or nonlinear. Laboratory tests were conducted on 1 and 2-in. diameter specimens of black iron Schedule 40 pipe in a cantilever configuration where the support is a threaded piping flange. The specimens were loaded monotonically into the inelastic region. The piping system was modeled as a straight pipe using Euler-Bernoulli beam theory with a support modeled as the proposed rotational spring. The correlation between test results and analytical predictions was quite good. A modified Ramberg-Osgood equation (1943) was used to model the nonlinear moment-rotational behavior of the support spring, and the criterion specified by ASME Boiler & Pressure Vessel Code (ASME, 2007) was used to determine the rotational limit for the threaded piping connection. DA - 2016/11/15/ PY - 2016/11/15/ DO - 10.1016/j.oceaneng.2016.09.030 VL - 127 SP - 1-6 SN - 0029-8018 KW - Nonlinear KW - Ramberg-Osgood KW - Piping KW - Connection KW - Threaded KW - Limit ER - TY - JOUR TI - Quantitative electrical imaging of three-dimensional moisture flow in cement-based materials AU - Smyl, Danny AU - Hallaji, Milad AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER AB - The presence of moisture significantly affects the mechanical, hydraulic, chemical, electrical, and thermal properties of cement-based and other porous materials, and therefore, methods for detecting and quantifying the moisture ingress in these materials are needed. Recent research studies have shown that the ingress of moisture in porous materials can be qualitatively imaged with Electrical Impedance Tomography (EIT) – an imaging modality which uses electrical measurements from object’s surface to reconstruct the electrical conductivity distribution inside the object. The aim of this study is to investigate whether EIT could image the three-dimensional volumetric moisture content within cement-based materials quantitatively. For this aim, we apply the so-called absolute imaging scheme to the EIT image reconstruction, and use an experimentally developed model for converting the electrical conductivity distribution to volumetric moisture content. The results of the experimental studies support the feasibility of EIT for quantitative imaging of three-dimensional moisture flows in cement-based materials. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.ijheatmasstransfer.2016.08.039 VL - 103 SP - 1348-1358 SN - 1879-2189 KW - Electrical Impedance Tomography (EIT) KW - Imaging KW - Non-destructive testing KW - Unsaturated moisture flow KW - X-ray imaging KW - Cement-based materials ER - TY - JOUR TI - Modeling water absorption in concrete and mortar with distributed damage AU - Smyl, D. AU - Ghasemzadeh, F. AU - Pour-Ghaz, M. T2 - Construction & Building Materials AB - The deterioration rate of concrete structures is directly influenced by the rate of moisture ingress. Modeling moisture ingress in concrete is therefore essential for quantitative estimation of the service life of concrete structures. While models for saturated moisture transport are commonly used, concrete, during its service life, is rarely saturated and some degree of damage is often present. In this work, we investigate whether classical isothermal unsaturated moisture transport can be used to simulate moisture ingress in damaged mortar and concrete and we compare the results of numerical simulations with experimental measurements of water sorption. The effect of hysteresis of moisture retention is also considered in the numerical simulations. The results indicate that the unsaturated moisture transport models well simulate early stages of moisture ingress at all damage levels, where capillary suction is the prominent mechanism. At later stages of moisture transport, where air diffusion and dissolution have a more significant contribution, simulations that consider moisture hysteresis compare most favorably with experimental results. DA - 2016/// PY - 2016/// DO - 10.1016/j.conbuildmat.2016.08.044 VL - 125 SP - 438-449 ER - TY - JOUR TI - Linking asphalt binder fatigue to asphalt mixture fatigue performance using viscoelastic continuum damage modeling AU - Safaei, Farinaz AU - Castorena, Cassie AU - Kim, Y. Richard T2 - MECHANICS OF TIME-DEPENDENT MATERIALS DA - 2016/8// PY - 2016/8// DO - 10.1007/s11043-016-9304-1 VL - 20 IS - 3 SP - 299-323 SN - 1573-2738 KW - Asphalt binder KW - Fatigue KW - Continuum damage modeling ER - TY - JOUR TI - Evaluation of Light-Duty Gasoline Vehicle Rated Fuel Economy Based on In-Use Measurements AU - Khan, Tanzila AU - Frey, H. Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - A study demonstrated a systematic method to assess the degree of concordance between estimated real-world and the U.S. Environmental Protection Agency (EPA) rated fuel economy for light-duty gasoline vehicles based on real-world emissions measurements. Cold engine start effects are accounted for in the real-world fuel economy and in comparison with EPA ratings. Portable emissions measurement systems were used to measure emissions of carbon dioxide, carbon monoxide, hydrocarbons, and nitrogen oxides of 122 vehicles on a specified test route consisting of various roads. Fuel economy of measured vehicles was estimated considering two cases: EPA standard driving cycles and real-world driving cycles. Average cold start emissions measurements from 32 vehicles were used in sensitivity analysis of fuel economy with respect to cold start. Real-world fuel economy estimates and comparison with rated fuel economy are not highly sensitive to cold start effects. On average, both the city and highway ratings are conservative compared with real-world fuel economy. However, there are proportions of vehicles that have lower real-world fuel economy than rated. The method demonstrated should be applied to additional vehicles and real-world driving cycles. Insights from these comparisons could motivate development of a more accurate rating scheme and identification of advice to consumers to improve their fuel economy. DA - 2016/// PY - 2016/// DO - 10.3141/2570-03 VL - 2570 IS - 2570 SP - 21-29 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976319253&partnerID=MN8TOARS ER - TY - JOUR TI - Electrical capacitance tomography to monitor unsaturated moisture ingress in cement-based materials AU - Voss, Antti AU - Pour-Ghaz, Mohammad AU - Vauhkonen, Marko AU - Seppanen, Aku T2 - CEMENT AND CONCRETE RESEARCH AB - This paper reports the investigation of the feasibility of electrical capacitance tomography (ECT) for monitoring unsaturated moisture flow in cement-based materials. ECT is an imaging modality in which the electrical permittivity distribution within an object is reconstructed based on measured capacitances between electrodes attached on the object's surface. In a series of experiments, mortar specimens with different water-cement mass ratios (w/c) (0.25, 0.45 & 0.60) were monitored with ECT during the moisture ingress. The results demonstrate that ECT is able to image the moisture ingress within the specimens, and further, to distinguish between different moisture flow rates in mortars with different porosities resulting from differing w/c ratios. These findings suggest that ECT could provide a tool for monitoring, visualizing and quantifying the rate of moisture ingress in cement-based materials non-destructively. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.cemconres.2016.07.011 VL - 89 SP - 158-167 SN - 1873-3948 KW - Non-destructive testing KW - Electrical capacitance tomography (ECT) KW - Permittivity KW - Imaging KW - Moisture flow ER - TY - JOUR TI - Comparison of Vehicle-Specific Fuel Use and Emissions Models Based on Externally and Internally Observable Activity Data AU - Hu, Jiangchuan AU - Frey, H. Christopher AU - Washburn, Scott S. T2 - TRANSPORTATION RESEARCH RECORD AB - On-road vehicles consume a substantial amount of fuel and emit air pollutants, including carbon monoxide, hydrocarbon, and nitrogen oxides. Increasing concern about air quality has meant increasing interest in accurate estimates of microscale vehicle energy use and emissions (EU&E). Vehicle EU&E rates are related to vehicle-specific power (VSP). For a given vehicle, VSP is a function of vehicle speed, acceleration, and grade, each of which can be categorized as an externally observable variable (EOV). However, internally observable variables (IOVs), such as manifold absolute pressure (MAP) and engine revolutions per minute (RPM), are more predictive of EU&E. Field measurements were conducted for 10 on-road vehicles using a portable emissions measurement system, an on-board diagnostic scan tool, and GPS receivers to measure exhaust concentrations and engine activity and to estimate road grade. VSP and the product of MAP and RPM ( P M×R ) are useful as indicators of engine load. IOV-based models were developed to predict EU&E rates. The IOV-based models typically performed better than EOV-based models. The models demonstrated could be integrated into next-generation traffic simulation programs, as well as into vehicle engine control units, to provide feedback on real-time emissions. DA - 2016/// PY - 2016/// DO - 10.3141/2570-04 VL - 2570 IS - 2570 SP - 30-38 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85014459431&partnerID=MN8TOARS ER - TY - JOUR TI - Comparison of Field Measurements to Methane Emissions Models at a New Landfill AU - Cruz, Florentino B. AU - Green, Roger B. AU - Hater, Gary R. AU - Chanton, Jeffrey P. AU - Thoma, Eben D. AU - Harvey, Tierney A. AU - Barlaz, Morton A. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Estimates of methane emissions from landfills rely primarily on models due to both technical and economic limitations. While models are easy to implement, there is uncertainty due to the use of parameters that are difficult to validate. The objective of this research was to compare modeled emissions using several greenhouse gas (GHG) emissions reporting protocols including: (1) Intergovernmental Panel on Climate Change (IPCC); (2) U.S. Environmental Protection Agency Greenhouse Gas Reporting Program (EPA GHGRP); (3) California Air Resources Board (CARB); and (4) Solid Waste Industry for Climate Solutions (SWICS), with measured emissions data collected over three calendar years from a young landfill with no gas collection system. By working with whole landfill measurements of fugitive methane emissions and methane oxidation, the collection efficiency could be set to zero, thus eliminating one source of parameter uncertainty. The models consistently overestimated annual methane emissions by a factor ranging from 4-31. Varying input parameters over reasonable ranges reduced this range to 1.3-8. Waste age at the studied landfill was less than four years and the results suggest the need for measurements at additional landfills to evaluate the accuracy of the tested models to young landfills. DA - 2016/9/6/ PY - 2016/9/6/ DO - 10.1021/acs.est.6b00415 VL - 50 IS - 17 SP - 9432-9441 SN - 1520-5851 ER - TY - JOUR TI - Collaborating in decision making of sustainable building design: An experimental study comparing CBA and WRC methods AU - Arroyo, Paz AU - Fuenzalida, Camila AU - Albert, Alex AU - Hallowell, Matthew R. T2 - ENERGY AND BUILDINGS AB - This study compares Choosing By Advantages (CBA) and Weighting Rating and Calculating (WRC) as Multiple Criteria Decision Making (MCDM) methods in how they support collaboration in groups, particularly pertaining to design decisions involving sustainability factors in architecture, engineering and construction industry. This study is based on an experiment done with 15 practitioners, where they formed 5 groups of 3 people each. The experiment used multiple baseline testing (MBT) and all groups made 12 decisions. The initial decisions were made using the WRC method and later, in a staggered manner between the fifth and ninth decision, the groups were taught to apply the CBA method. The CBA method is considered to be the intervention in the experimental design. Four dependent variables were analyzed: (1) time to reach consensus, (2) satisfaction with the final decision, (3) personal frustration during the decision, and (4) perceived frustration from others during the decision. The results showed with statistical significance that CBA was faster than WRC for reaching consensus and presents less personal and perceived frustration during the decision. The results do not show statistical support in favor of any method regarding satisfaction with the final decision. DA - 2016/9/15/ PY - 2016/9/15/ DO - 10.1016/j.enbuild.2016.05.079 VL - 128 SP - 132-142 SN - 1872-6178 KW - Decision-making KW - Choosing by advantages KW - CBA KW - Sustainability KW - Design management KW - Multiple baseline testing ER - TY - JOUR TI - Cellular Automata Modeling Framework for Urban Water Reuse Planning and Management AU - Kandiah, Venu K. AU - Berglund, Emily Z. AU - Binder, Andrew R. T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - Water reuse provides a sustainable approach to balance water supply and demand in urban areas, and reclaimed water can be used for nonpotable applications to reduce demands on freshwater sources. Construction of a secondary network is required to distribute reclaimed water. Implementing water reuse projects on a wider scale is challenged by the need for communitywide public acceptance and adoption, which may be a dynamic and adaptive process. The adoption of new water infrastructure can drive hydraulic conditions in both the reclaimed network and an existing drinking water network. This research develops a dynamic modeling framework using a cellular automata (CA) approach to simulate consumer adoption of reclaimed water. The framework couples the CA model of consumer adoption with water distribution system models of the drinking and reclaimed water systems. Emergent distribution system hydraulic conditions are simulated, and the capacity utilization and system performance are evaluated as consumers adopt water reuse. The Town of Cary, North Carolina, is used as case study to develop and demonstrate the modeling framework. The CA parameters and rules are developed and validated using data about the addition of new accounts for the period 2001–2012. Projected water reuse adoption is simulated in Cary for the period 2012–2030, and impacts on the existing drinking water infrastructure and planned reclaimed water infrastructure are evaluated. DA - 2016/12// PY - 2016/12// DO - 10.1061/(asce)wr.1943-5452.0000696 VL - 142 IS - 12 SP - SN - 1943-5452 KW - Complex adaptive system KW - Diffusion of innovation KW - Dual water system KW - Sociotechnical transition KW - Urban water management KW - Water reuse ER - TY - JOUR TI - CFD for wastewater treatment: an overview AU - Samstag, R. W. AU - Ducoste, J. J. AU - Griborio, A. AU - Nopens, I. AU - Batstone, D. J. AU - Wicks, J. D. AU - Saunders, S. AU - Wicklein, E. A. AU - Kenny, G. AU - Laurent, J. AU - al., T2 - WATER SCIENCE AND TECHNOLOGY AB - Computational fluid dynamics (CFD) is a rapidly emerging field in wastewater treatment (WWT), with application to almost all unit processes. This paper provides an overview of CFD applied to a wide range of unit processes in water and WWT from hydraulic elements like flow splitting to physical, chemical and biological processes like suspended growth nutrient removal and anaerobic digestion. The paper's focus is on articulating the state of practice and research and development needs. The level of CFD's capability varies between different process units, with a high frequency of application in the areas of final sedimentation, activated sludge basin modelling and disinfection, and greater needs in primary sedimentation and anaerobic digestion. While approaches are comprehensive, generally capable of incorporating non-Newtonian fluids, multiphase systems and biokinetics, they are not broad, and further work should be done to address the diversity of process designs. Many units have not been addressed to date. Further needs are identified throughout, but common requirements include improved particle aggregation and breakup (flocculation), and improved coupling of biology and hydraulics. DA - 2016/8// PY - 2016/8// DO - 10.2166/wst.2016.249 VL - 74 IS - 3 SP - 549-563 SN - 1996-9732 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84982261315&partnerID=MN8TOARS KW - biokinetics KW - computational fluid dynamics KW - digestion KW - flow splitting KW - modelling KW - sedimentation ER - TY - JOUR TI - Behavioral Effects of Completing a Critical Link in the American Tobacco Trail AU - Cook, Thomas J. AU - Sarah W. O'Brien, AU - Jackson, Kristy N. AU - Findley, Daniel J. AU - Searcy, Sarah E. T2 - TRANSPORTATION RESEARCH RECORD AB - This study responded to a unique opportunity to determine behavioral changes that resulted from the construction of a critical link of the American Tobacco Trail (ATT) in Durham, North Carolina. Observational data were collected both before and after construction of a bicycle-and-pedestrian bridge that linked two separate segments of the regional greenway. Before construction of the bridge and trail connections, the two segments of the ATT were separated by Interstate 40. Heavy traffic on local streets as well as a lack of bicycle and pedestrian facilities in the area provided additional barriers to active travel between the two ATT segments. The Institute of Transportation Research and Education conducted intercept surveys and manual counts on the two trail segments before and after construction of the bridge. The before-and-after data were compared to determine the changes that occurred in the use of the ATT and the accompanying social, public health, transportation, and economic effects. DA - 2016/// PY - 2016/// DO - 10.3141/2598-03 VL - 2598 IS - 2598 SP - 19-26 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84976295627&partnerID=MN8TOARS ER - TY - JOUR TI - Analysis of Workflow Variability's Impacts on Trade and Project Performance AU - Javanmardi, Ashtad AU - Abbasian-Hosseini, S. Alireza AU - Liu, Min AU - Hsiang, Simon M. T2 - ICSDEC 2016 - INTEGRATING DATA SCIENCE, CONSTRUCTION AND SUSTAINABILITY AB - Variability, defined as the deviation of production capacity from an expected average, has a negative impact on the productivity of downstream trades and the entire system. It increases project duration, lost capacities and inventory of the downstream trades. This paper, using Parade Game Simulation, aims to identify the key trade(s) of a single-line production system that contribute(s) the most in reducing/increasing the project duration, total lost capacity and total inventory buffer. The simulation model includes seven trades with two different variability levels. A cooperative game theory was utilized to investigate how the productivity of downstream trades and the entire system is affected by the location of variability. This research revealed the key trades and strategic assignments of trades to maximize the trade and system performance. The findings are beneficial to construction managers as it helps them to manage the workflow efficiently by focusing on the key trades. DA - 2016/// PY - 2016/// DO - 10.1016/j.proeng.2016.04.075 VL - 145 SP - 281-287 SN - 1877-7058 KW - Reliability KW - Variability KW - Discrete Event Simulation (DES) KW - Game theory ER - TY - JOUR TI - A viscoelastic-based model for predicting the strength of asphalt. concrete in direct tension AU - Keshavarzi, Behrooz AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The modeling of asphalt concrete behavior under monotonic loading plays an important role in investigating the low temperature behavior of pavement material. Further, any proposed method should be able to consider the rate and temperature dependency of asphalt concrete. This paper presents a new method for simulating the behavior of asphalt concrete in uniaxial tension. Direct tension monotonic testing that incorporates a constant crosshead displacement rate and various temperatures was used in the experimental investigation to simulate thermal cracking of asphalt concrete. Viscoelastic continuum damage theory was applied to simulate the asphalt behavior in direct tension. This theory is able to model distributed damage within the material under both constant and dropping temperatures. A damage characteristic curve, which has been proven to represent the intrinsic property of the material, was used to simulate the damage evolution during testing. The proposed method features a single ordinary differential equation that is solved to provide the damage evolution. The results show that the predicted stress matches the measured data well for tests conducted at North Carolina State University and by other agencies. Implementing the proposed method in a finite element code provides a strong mechanistic model to predict asphalt fracture under thermal loading. DA - 2016/9/30/ PY - 2016/9/30/ DO - 10.1016/j.conbuildmat.2016.06.089 VL - 122 SP - 721-727 SN - 1879-0526 KW - Asphalt concrete KW - Thermal cracking KW - Viscoelastic continuum damage KW - Temperature-induced stress KW - Thermal loading ER - TY - JOUR TI - Unified viscoplasticity modeling for isothermal low-cycle fatigue and fatigue-creep stress-strain responses of Haynes 230 AU - Ahmed, Raasheduddin AU - Barrett, Paul R. AU - Hassan, Tasnim T2 - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES AB - A robust cyclic viscoplasticity model is developed for simulating a broad set of isothermal, low-cycle fatigue and fatigue-creep responses of Haynes 230 (HA 230) under uniaxial loading. High temperature components experiencing thermo-mechanical fatigue failures can be designed considering their failure responses such that their fatigue life is predictable. Hence, design of high temperature components in aerospace, automobile, nuclear power, and chemical industries should be based on viscoplastic nonlinear analysis using a robust constitutive model. A unified viscoplasticity model based on the nonlinear kinematic hardening rule of Chaboche with several added features for strain-range dependence, rate-dependence, static recovery, and mean stress evolution is developed and evaluated against a broad set of HA 230 responses. Robustness of the constitutive model is demonstrated against predicting fatigue and dwell period stress relaxation responses under uniaxial strain-controlled loading for a broad temperature range of 25–982 °C and strain rate range of 1.1×10−2 to 2.6×10−5/s. Parameter determination of such an advanced model is discussed showing the importance of a well thought out experimental database and thereby providing physical meaning to model parameters. DA - 2016/6/15/ PY - 2016/6/15/ DO - 10.1016/j.ijsolstr.2016.03.012 VL - 88-89 SP - 131-145 SN - 1879-2146 KW - Haynes 230 KW - Cyclic viscoplasticity KW - Constitutive modeling KW - Fatigue KW - Fatigue-creep ER - TY - JOUR TI - Systematic Evaluation of Industrial, Commercial, and Institutional Food Waste Management Strategies in the United States AU - Hodge, Keith L. AU - Levis, James W. AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. T2 - Environmental Science & Technology AB - New regulations and targets limiting the disposal of food waste have been recently enacted in numerous jurisdictions. This analysis evaluated selected environmental implications of food waste management policies using life-cycle assessment. Scenarios were developed to evaluate management alternatives applicable to the waste discarded at facilities where food waste is a large component of the waste (e.g., restaurants, grocery stores, and food processors). Options considered include anaerobic digestion (AD), aerobic composting, waste-to-energy combustion (WTE), and landfilling, and multiple performance levels were considered for each option. The global warming impact ranged from approximately −350 to −45 kg CO2e Mg–1 of waste for scenarios using AD, −190 to 62 kg CO2e Mg–1 for those using composting, −350 to −28 kg CO2e Mg–1 when all waste was managed by WTE, and −260 to 260 kg CO2e Mg–1 when all waste was landfilled. Landfill diversion was found to reduce emissions, and diverting food waste from WTE generally increased emissions. The analysis further found that when a 20 year GWP was used instead of a 100 year GWP, every scenario including WTE was preferable to every scenario including landfill. Jurisdictions seeking to enact food waste disposal regulations should consider regional factors and material properties before duplicating existing statutes. DA - 2016/7/28/ PY - 2016/7/28/ DO - 10.1021/acs.est.6b00893 VL - 50 IS - 16 SP - 8444-8452 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.6b00893 DB - Crossref ER - TY - JOUR TI - Sequential Measurement of Intermodal Variability in Public Transportation PM2.5 and CO Exposure Concentrations AU - Che, W. W. AU - Frey, H. Christopher AU - Lau, Alexis K. H. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - A sequential measurement method is demonstrated for quantifying the variability in exposure concentration during public transportation. This method was applied in Hong Kong by measuring PM2.5 and CO concentrations along a route connecting 13 transportation-related microenvironments within 3-4 h. The study design takes into account ventilation, proximity to local sources, area-wide air quality, and meteorological conditions. Portable instruments were compacted into a backpack to facilitate measurement under crowded transportation conditions and to quantify personal exposure by sampling at nose level. The route included stops next to three roadside monitors to enable comparison of fixed site and exposure concentrations. PM2.5 exposure concentrations were correlated with the roadside monitors, despite differences in averaging time, detection method, and sampling location. Although highly correlated in temporal trend, PM2.5 concentrations varied significantly among microenvironments, with mean concentration ratios versus roadside monitor ranging from 0.5 for MTR train to 1.3 for bus terminal. Measured inter-run variability provides insight regarding the sample size needed to discriminate between microenvironments with increased statistical significance. The study results illustrate the utility of sequential measurement of microenvironments and policy-relevant insights for exposure mitigation and management. DA - 2016/8/16/ PY - 2016/8/16/ DO - 10.1021/acs.est.6b01594 VL - 50 IS - 16 SP - 8760-8769 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84983049668&partnerID=MN8TOARS ER - TY - JOUR TI - Release of Per- and Polyfluoroalkyl Substances (PFASs) from Carpet and Clothing in Model Anaerobic Landfill Reactors AU - Lang, Johnsie R. AU - Allred, B. McKay AU - Peaslee, Graham F. AU - Field, Jennifer A. AU - Barlaz, Morton A. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Discarded carpet and clothing are potential sources of per- and polyfluoroalkyl substances (PFASs) in landfill leachate, but little is known about their release when disposed in landfills. The concentrations of 70 PFASs in the aqueous phase of anaerobic model landfill reactors filled with carpet or clothing were monitored under biologically active and abiotic conditions. For carpet, total PFAS release was greater in live than abiotic reactors, with an average of 8.5 nmol/L and 0.62 nmol/L after 552 days, respectively. Release in live carpet reactors was primarily due to 5:3 fluorotelomer carboxylic acid (FTCA - 3.9 nmol/L) and perfluorohexanoic carboxylic acid (PFHxA - 2.9 nmol/L). For clothing, release was more dependent on sample heterogeneity than the presence of biological activity, with 0.63, 21.7, 2.6, and 6.3 nmol/L for two live and two abiotic reactors after 519 days, respectively. Release in the clothing reactors was largely due to perfluorooctatonic carboxylic acid (PFOA), with low relative concentrations of measured biotransformation precursors (FTCAs). For carpet and clothing reactors, the majority of PFAS release was not measured until after day 100. Results demonstrate that carpet and clothing are likely sources of PFASs in landfill leachate. DA - 2016/5/17/ PY - 2016/5/17/ DO - 10.1021/acs.est.5b06237 VL - 50 IS - 10 SP - 5024-5032 SN - 1520-5851 ER - TY - JOUR TI - Isothermal low-cycle fatigue and fatigue-creep of Haynes 230 AU - Barrett, Paul R. AU - Ahmed, Raasheduddin AU - Menon, Mamballykalathil AU - Hassan, Tasnim T2 - INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES AB - Service temperature of airplane gas turbine engine combustors fluctuates between ambient to as high as 982 °C, during which structural constraints induce cyclic stresses and strains resulting in thermo-mechanical fatigue damage accumulation in the combustor liner. In order to substantially improve the current design methodologies or low-cycle fatigue (LCF) life predictions of such high-temperature components, it is essential to develop an experimentally validated advanced constitutive model. This requires a broad set of fatigue data of the combustor liner material, Haynes 230 (HA 230) – a nickel-based superalloy, to characterize its fatigue failure responses. Hence, a systematic set of isothermal experiments are conducted prescribing uniaxial strain-controlled loading cycles, with and without a compression peak strain-dwell, with and without a mean strain, at seven different temperatures in the range of 24–982 °C and at three strain rates. The experimental responses are critically examined to explore various fatigue failure responses of HA230, which is a complex material showing unique fatigue-creep, strain rate sensitivity, strain range dependence, temperature dependence and dynamic strain aging (DSA) properties. DSA is found to occur in the temperature domain 427–760 °C. Isothermal experimental responses at different strain rates show that HA 230 can be considered rate-independent at and below 760 °C. However, stress relaxation is observed at lower temperatures up to 649 °C during the peak strain-dwell period. Finally, fatigue lives of HA 230 from the isothermal experiments are found to decrease with increase in temperature. These experimental responses are presented and challenges in constitutive model development are discussed. DA - 2016/6/15/ PY - 2016/6/15/ DO - 10.1016/j.ijsolstr.2016.03.011 VL - 88-89 SP - 146-164 SN - 1879-2146 KW - Haynes 230 KW - High temperature LCF KW - Fatigue-creep KW - Fatigue life KW - Dynamic strain aging ER - TY - JOUR TI - Improving Hazard-Recognition Performance and Safety Training Outcomes: Integrating Strategies for Training Transfer AU - Namian, Mostafa AU - Albert, Alex AU - Zuluaga, Carlos M. AU - Jaselskis, Edward J. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Most construction safety activities focus on managing identified hazards. Hazards that remain unrecognized, and as a result unmanaged, can potentially result in catastrophic and unexpected injuries. Therefore, proper hazard recognition is foundational to the success of any safety program. However, recent research has revealed that a large proportion of construction hazards remain unrecognized in construction projects. To improve hazard recognition performance, employers provide their workers with safety and hazard recognition training. Despite these efforts, desirable levels of hazard recognition have not been achieved, and the anticipated return on investment (ROI) from training has not been attained. Such failures in training efforts are partly because knowledge acquired through training programs is often not transferred or applied in the workplace. Subsequently, training efforts do not alter work practices or behavior once workers return to the field. Other reasons for training failure include improper training delivery and the adoption of low-engagement training methods. To advance theory and practice in hazard recognition, training transfer, and training delivery, the objectives of this study were to (1) identify training transfer elements that maximize the transfer of safety training, (2) evaluate the relative effectiveness of the identified training transfer elements in transferring safety knowledge gained through training programs, and (3) assess the interaction effect between training method (i.e., high-engagement versus low-engagement training) and training transfer levels on hazard recognition performance. The objectives of the study were accomplished by gathering input from construction industry experts through interviews, questionnaire surveys, and the analysis of empirical data gathered from 51 case projects in the United States. The results of the study revealed that training efforts may be undermined if training transfer elements are not synergistically adopted. Specifically, the findings suggest that safety training is necessary, but is not sufficient to maximize training outcomes such as hazard recognition. To maximize safety training outcomes, employers must adopt training transfer elements along with high-engagement training methods. This study represents the first formal attempt to evaluate the role of training transfer elements in the construction context. DA - 2016/10// PY - 2016/10// DO - 10.1061/(asce)co.1943-7862.0001160 VL - 142 IS - 10 SP - SN - 1943-7862 KW - Construction safety KW - Safety training KW - Hazard identification KW - Hazard recognition KW - Training transfer KW - Training delivery KW - Safety management KW - Labor and personnel issues ER - TY - JOUR TI - Identifying transportation disadvantage: Mixed-methods analysis combining GIS mapping with qualitative data AU - Shay, Elizabeth AU - Combs, Tabitha S. AU - Findley, Daniel AU - Kolosna, Carl AU - Madeley, Michelle AU - Salvesen, David T2 - TRANSPORT POLICY AB - Rural residents, including elderly, low-income or people with language or physical mobility challenges, may experience transportation disadvantage when land use patterns, built environment and transportation services fail to meet their mobility needs. A technique for identifying transportation-disadvantaged populations, intended for use by local practitioners and designed with their skills and professional routines in mind, was piloted in five rural counties in North Carolina. Maps showing areas of elevated theoretical risk of transportation disadvantage were constructed by overlaying layers of readily available, Census-based geospatial data, to generate composite maps where increasing intensity of shading denotes populations with multiple risk factors. The maps were used in key informant interviews with local transportation-relevant professionals to access their expert knowledge, and in focus groups with non-expert residents to probe their travel routines and need to access essential goods, services and activities. These multiple data sources supported an iterative process of initial mapping, stakeholder outreach, revised mapping, and continued discussion. Our findings both corroborated some a priori expectations, and yielded unexpected insights into which residents may experience transportation disadvantage and how they respond. The work demonstrates how local knowledge can be used to identify unique or non-spatial components of transportation disadvantage, and underscores the importance of locally specific knowledge to support planning efforts to identify and ultimately to address transportation disadvantage. DA - 2016/5// PY - 2016/5// DO - 10.1016/j.tranpol.2016.03.002 VL - 48 SP - 129-138 SN - 1879-310X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85013235462&partnerID=MN8TOARS KW - Transportation disadvantage KW - Qualitative research methods KW - Key informant interviews KW - Focus groups KW - Rural transportation ER - TY - JOUR TI - Identifying fatigue failure in asphalt binder time sweep tests AU - Wang, Chao AU - Zhang, Han AU - Castorena, Cassie AU - Zhang, Jinxi AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Identification of fatigue failure of asphalt binder in time sweep test results remains a question crucial to asphalt binder fatigue performance evaluation and prediction. This paper presents a comparison of different analysis approaches for defining the occurrence of fatigue failure during time sweep fatigue tests conducted in both control-displacement and control-stress loading modes. The candidate failure definitions evaluated include the traditional 50% reduction in stiffness parameter (S0.5), dissipated energy indicators including the dissipated energy ratio (DER) and the ratio of dissipated energy change (RDEC), as well as two phenomenological parameters corresponding to the peak in S × N and peak in phase angle. Both phenomenological parameters and dissipated energy based indicators were found to be effective in defining fatigue failure. Statistical analysis results further indicate that maximum S × N, maximum phase angle and RDEC approach provide equivalent fatigue life results, however, peak in S × N is strongly recommended for detecting fatigue failure of asphalt binder in time sweep tests because it is easy to calculate and well defined. DA - 2016/9/15/ PY - 2016/9/15/ DO - 10.1016/j.conbuildmat.2016.06.020 VL - 121 SP - 535-546 SN - 1879-0526 KW - Asphalt binder fatigue KW - Fatigue damage KW - Failure definition KW - Dissipated energy ER - TY - JOUR TI - Health and Climate-Relevant Pollutant Concentrations from a Carbon-Finance Approved Cookstove Intervention in Rural India AU - Aung, Ther W. AU - Jain, Grishma AU - Sethuraman, Karthik AU - Baumgartner, Jill AU - Reynolds, Conor AU - Grieshop, Andrew P. AU - Marshall, Julian D. AU - Brauer, Michael T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Efforts to introduce more efficient stoves increasingly leverage carbon-finance to scale up dissemination of interventions. We conducted a randomized intervention study to evaluate a Clean Development Mechanism approved stove replacement impact on fuelwood usage, and climate and health-relevant air pollutants. We randomly assigned 187 households to either receive the intervention or to continue using traditional stoves. Measurements of fine particulate matter (PM2.5) and absorbance were conducted in cooking areas, village center and at upwind background site. There were minor and overlapping seasonal differences (post- minus preintervention change) between control and intervention groups for median (95% CI) fuel use (-0.60 (-1.02, -0.22) vs -0.52 (-1.07, 0.00) kg day(-1)), and 24 h absorbance (35 (18, 60) vs 36 (22, 50) × 10(-6) m(-1)); for 24 h PM2.5, there was a higher (139 (61,229) vs 73(-6, 156) μg m(-3))) increase in control compared to intervention homes between the two seasons. Forty percent of the intervention homes continued using traditional stoves. For intervention homes, absorbance-to-mass ratios suggest a higher proportion of black carbon in PM2.5 emitted from intervention compared with traditional stoves. Absent of field-based evaluation, stove interventions may be pursued that fail to realize expected carbon reductions or anticipated health and climate cobenefits. DA - 2016/7/5/ PY - 2016/7/5/ DO - 10.1021/acs.est.5b06208 VL - 50 IS - 13 SP - 7228-7238 SN - 1520-5851 ER - TY - JOUR TI - "Oops" Simulation: Cost-Benefits Trade-Off Analysis of Reliable Planning for Construction Activities AU - Hajifathalian, Kiarash AU - Howell, Gregory AU - Wambeke, Brad W. AU - Hsiang, Simon M. AU - Liu, Min T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - “The Oops Game” explores the question, how much should be invested in planning? The simulation offers the opportunity to reduce the risk of an “Oops” by collecting more information or to go ahead and make the choice with the information at hand. There are two extreme strategies. Nothing is invested in planning in the so-called Guts-ball approach, but this increases the likelihood that an “Oops” will occur and thus increases the cost to complete the project. The second strategy is to invest in planning before attempting to build. This will increase the cost of planning upfront, but may reduce the risk and cost of an “Oops” in building. In reality, the cost and value of planning depends on the complexity level of the project, the amount of uncertainty that we need to deal with it, and the cost of an “Oops.” We used computer simulation to show how the value of planning is sensitive to those factors. The results showed that the project with the reliable planning strategy had a 35% higher productivity and a cost-benefit ratio of 13∶1. The contribution to the body of knowledge of “The Oops Game” lies in providing a simple and effective means to show the value of planning to construction practitioners and students. The findings from this research fill in the gap of knowledge in quantifying the value of plan under different circumstance for construction projects. DA - 2016/8// PY - 2016/8// DO - 10.1061/(asce)co.1943-7862.0001135 VL - 142 IS - 8 SP - SN - 1943-7862 KW - Planning KW - Cost of project KW - Productivity KW - Performance reliability KW - Computer aided simulation KW - Labor and personnel issues ER - TY - JOUR TI - Trends in Population and Demographics of US Environmental Engineering Students and Faculty from 2005 to 2013 AU - Blaney, Lee AU - Kandiah, Ramanitharan AU - Ducoste, Joel J. AU - Perlinger, Judith A. AU - Bartelt-Hunt, Shannon L. T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - Although modern environmental engineering was established in the mid 1900s, the field has arguably evolved into its own professional discipline only in the past 3–4 decades. During this time, the number of environmental engineering students, faculty, and practitioners has grown dramatically, and many environmental engineering BS degree programs were established. To better assess this growth, we have conducted an analysis of the demographics of environmental engineering students and faculty using the American Society for Engineering Education (ASEE) Engineering Data Management System. One limitation of the ASEE database is that only students and faculty primarily associated with environmental engineering degrees and programs, respectively, are counted; therefore, students and faculty related to environmental engineering tracks within civil and chemical engineering programs are excluded from this analysis. From 2005 to 2013, the number of BS, MS, and PhD degrees awarded rose by 90%, 27%, and 39%, respectively; furthermore, these growth rates exceeded those of civil and chemical engineering at all levels. As a consequence, the BS student-to-faculty ratio rose from 8 in 2005 to 35 in 2013. Hispanic American, African American, and Native American students are underrepresented in environmental engineering programs at all levels. Representation and retention of African American students is particularly concerning, since this group exhibited negative retention trends from the 2006 to 2010 BS cohorts. Gender demographics were reasonably representative with 46% of all environmental engineering degrees awarded to women in 2013. Some gains were found in representation of ethnic and racial minorities and women in environmental engineering faculty at the associate professor level. Minimal gains were observed at the assistant professor rank. However, 88% of full professors are Caucasian, and 85% are men. These findings suggest that increased efforts are needed to recruit and retain students from underrepresented groups to environmental engineering and encourage them to pursue careers in academia. DA - 2016/8// PY - 2016/8// DO - 10.1089/ees.2016.0063 VL - 33 IS - 8 SP - 578-590 SN - 1557-9018 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84979691960&partnerID=MN8TOARS KW - assessment KW - innovations in environmental education KW - diversity KW - demographics KW - outreach ER - TY - JOUR TI - Structural characteristics and development of the cake layer in a dynamic membrane bioreactor AU - Xiong, Jianglei AU - Fu, Dafang AU - Singh, Rajendra Prasad AU - Ducoste, Joel J. T2 - SEPARATION AND PURIFICATION TECHNOLOGY AB - The cake layers play a key role in the rejection of particles in dynamic membrane bioreactors and produces most of the resistance. This research aims to directly observe and measure the transient structure of the cake layers at different times and depths. The results showed the membrane flux remained relatively stable for the first 30 h, but decreased from 110 L/m2 h to 88 L/m2 h in the next 20 h. The membrane resistance was highly correlated with the cake layer thickness. The porosity and average pore diameter obtained from the scanning electron microcopy (SEM) pictures displayed no temporal variations, as only the new generated surface of the cake layer can be observed by SEM. However, the specific pore volume and surface area based on the Brunauer–Emmett–Teller (BET) nitrogen adsorption results displayed an initial decline, from 0.30 cc/g to 0.22 cc/g, due to the disappearance of the small diameter pores (1–10 nm) with time. The large diameter pores (30–250 nm) accounted for the majority of the cumulative pore volumes in all samples, as well as in the top layer, middle layer, and bottom layer. The specific pore volume and specific surface area exhibited a decline from the top layer to bottom layer, from 0.38 cc/g to 0.21 cc/g, due to the blockage of large diameter pores. In addition, BET nitrogen adsorption data provided comprehensive structural characteristics of the cake layers. DA - 2016/7/14/ PY - 2016/7/14/ DO - 10.1016/j.seppur.2016.04.040 VL - 167 SP - 88-96 SN - 1873-3794 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84966928788&partnerID=MN8TOARS KW - Self-forming dynamic membrane KW - Cake layer KW - Dynamic membrane structure KW - Membrane fouling ER - TY - JOUR TI - Strengthening of steel plates subjected to uniaxial compression using small-diameter CFRP strands AU - Kazem, Hamid AU - Guaderrama, Lucas AU - Selim, Hatem AU - Rizkalla, Sami AU - Kobayashi, Akira T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper presents the results of a study that was carried out to investigate the use of small-diameter CFRP strands for strengthening steel plates subjected to uniaxial compression. This study is part of a comprehensive research program to evaluate the use of the small-diameter CFRP strands for shear strengthening of steel girders. The research in this paper was undertaken to examine the bond characteristics of the proposed material which is expected to eliminate the debonding failure observed for CFRP laminates strengthening system and to resist the compressive stresses induced in high shear zones. The small-diameter CFRP strands are stitched together with a gap between the strands to allow each strand to be completely covered by the adhesive material. The effectiveness of the strengthening system was investigated by varying various parameters believed to affect the overall behavior including the slenderness ratio of the steel plates as well as mechanical properties and reinforcement ratios of the CFRP strands. Strengthened plates exhibited higher buckling capacity in comparison to similar plates without CFRP strands. In addition, the small-diameter CFRP strands did not show any signs of debonding at large lateral deformation associated with elastic buckling. DA - 2016/5/15/ PY - 2016/5/15/ DO - 10.1016/j.conbuildmat.2016.02.028 VL - 111 SP - 223-236 SN - 1879-0526 KW - Carbon fiber KW - Buckling KW - Debonding KW - Steel ER - TY - JOUR TI - Shifts in microbial communities in bioaugmented grease interceptors removing fat, oil, and grease (FOG) AU - He, Xia AU - So, Mark Jason AU - de los Reyes, Francis L. T2 - Applied Microbiology and Biotechnology DA - 2016/2/27/ PY - 2016/2/27/ DO - 10.1007/s00253-016-7398-7 VL - 100 IS - 16 SP - 7025-7035 J2 - Appl Microbiol Biotechnol LA - en OP - SN - 0175-7598 1432-0614 UR - http://dx.doi.org/10.1007/s00253-016-7398-7 DB - Crossref KW - Grease interceptors KW - Microbial community KW - Bioaugmentation KW - Fat, oil, and grease(FOG) KW - T-RFLP KW - Clone library ER - TY - JOUR TI - Modelling to generate alternatives with an energy system optimization model AU - DeCarolis, J. F. AU - Babaee, S. AU - Li, B. AU - Kanungo, S. T2 - ENVIRONMENTAL MODELLING & SOFTWARE AB - Energy system optimization models (ESOMs) should be used in an interactive way to uncover knife-edge solutions, explore alternative system configurations, and suggest different ways to achieve policy objectives under conditions of deep uncertainty. In this paper, we do so by employing an existing optimization technique called modeling to generate alternatives (MGA), which involves a change in the model structure in order to systematically explore the near-optimal decision space. The MGA capability is incorporated into Tools for Energy Model Optimization and Analysis (Temoa), an open source framework that also includes a technology rich, bottom up ESOM. In this analysis, Temoa is used to explore alternative energy futures in a simplified single region energy system that represents the U.S. electric sector and a portion of the light duty transport sector. Given the dataset limitations, we place greater emphasis on the methodological approach rather than specific results. DA - 2016/5// PY - 2016/5// DO - 10.1016/j.envsoft.2015.11.019 VL - 79 SP - 300-310 SN - 1873-6726 KW - Mathematical modeling KW - Energy systems KW - Optimization KW - Uncertainty ER - TY - JOUR TI - Improved Mode I fracture resistance of CFRP composites by reinforcing epoxy matrix with recycled short milled carbon fibre AU - Cholake, Sagar T. AU - Moran, Grainne AU - Joe, Bill AU - Bai, Yu AU - Raman, R. K. Singh AU - Zhao, X. L. AU - Rizkalla, Sami AU - Bandyopadhyay, Sri T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper proves that incorporation of recycled short milled carbon fibre (SMCF) in epoxy resin can lead to the generation of significantly tougher carbon fibre reinforced polymer (CFRP) systems in a cost effective manner for infrastructural applications. Structural epoxy resin is modified by adding 5 and 10 wt.% of SMCF particles and the ‘fracture toughness’ of the modified matrix (GICM) is observed to be increased by 300% and 700% respectively. Subsequently, the SMCF modified epoxy resins were used to fabricate unidirectional carbon fibre reinforced laminates and tested under Mode I crack opening. The SMCF reinforcement showed 50% and 64% improvement in the laminates fracture toughness (GICC) after adding 5% and 10% SMCF by wt., respectively. Scanning electron microscope images of the fracture surface highlight improved debonding and pull-out mechanisms contributing to the additional fracture toughness, and at the same time there was no evidence of fibre clustering. DA - 2016/5/15/ PY - 2016/5/15/ DO - 10.1016/j.conbuildmat.2016.02.039 VL - 111 SP - 399-407 SN - 1879-0526 KW - Particulate reinforcement KW - Fracture toughness KW - Epoxy KW - Milled carbon fibre ER - TY - JOUR TI - Identifying watershed, landscape, and engineering design factors that influence the biotic condition of restored streams AU - Doll, B. AU - Jennings, G. AU - Spooner, J. AU - Penrose, D. AU - Usset, J. AU - Blackwell, J. AU - Fernandez, M. T2 - Water AB - Restored stream reaches at 79 sites across North Carolina were sampled for aquatic macroinvertebrates using a rapid bioassessment protocol. Morphological design parameters and geographic factors, including watershed and landscape parameters (e.g., valley slope, substrate), were also compiled for these streams. Principal component regression analyses revealed correlations between design and landscape variables with macroinvertebrate metrics. The correlations were strengthened by adding watershed variables. Ridge regression was used to find the best-fit model for predicting dominant taxa from the “pollution sensitive” orders of Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies), or EPT taxa, resulting in coefficient weights that were most interpretable relative to site selection and design parameters. Results indicate that larger (wider) streams located in the mountains and foothills where there are steeper valleys, larger substrate, and undeveloped watersheds are expected to have higher numbers of dominant EPT taxa. In addition, EPT taxa numbers are positively correlated with accessible floodplain width and negatively correlated with width-to-depth ratio and sinuosity. This study indicates that both site selection and design should be carefully considered in order to maximize the resulting biotic condition and associated potential ecological uplift of the stream. DA - 2016/// PY - 2016/// DO - 10.3390/w8040151 VL - 8 IS - 4 UR - http://www.mdpi.com/2073-4441/8/4/151 KW - rivers/streams KW - restoration KW - macroinvertebrates KW - watersheds ER - TY - JOUR TI - Exploring Divergent Volatility Properties from Yield and Thermodenuder Measurements of Secondary Organic Aerosol from alpha-Pinene Ozonolysis AU - Saha, Provat K. AU - Grieshop, Andrew P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - There are large uncertainties in the parameters dictating the gas-particle partitioning of secondary organic aerosols (SOA), although this process has major influences on their atmospheric lifecycle. Here, we extract parameters that describe the partitioning of SOA from α-pinene ozonolysis using measurements from a dual-thermodenuder (TD) system that constrains both the equilibrium and the kinetic properties that dictate SOA phase partitioning. Parallel TDs that vary in temperature and residence time were used with an evaporation-kinetics model to extract parameter values. An evaporation coefficient of an order of 0.1 best describes the observed evaporation, suggesting equilibration time scales of atmospheric SOA on the order of minutes to hours. A total of 20–40% of SOA mass consists of low-volatility material (saturation concentration of <0.3 μg m–3) in the TD-derived SOA volatility distribution. While distinct from existing parametrizations from aerosol growth experiments, derived values are consistent with recent observations of slow room-temperature evaporation of SOA and contributions from extremely low volatility organic compounds formed during α-pinene ozonolysis. The volatility parameters thus determined suggest that SOA yields and enthalpies of evaporation are substantially higher, and products less volatile, than is currently assumed in atmospheric models. These results will help improve the representation of SOA in air-quality and climate models. DA - 2016/6/7/ PY - 2016/6/7/ DO - 10.1021/acs.est.6b00303 VL - 50 IS - 11 SP - 5740-5749 SN - 1520-5851 ER - TY - JOUR TI - Development and Comparative Analysis of Construction Industry Labor Productivity Metrics AU - Vereen, Stephanie C. AU - Rasdorf, William AU - Hummer, Joseph E. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Construction industry labor productivity is an important metric that provides feedback about industry level trends and improvements. However, labor productivity for the construction industry has historically been elusive to define and determine both qualitatively and quantitatively. Existing research studies have provided different methods to calculate productivity at a variety of levels (activity, project, industry), but none proved universally satisfying. This paper presents a new metric for quantifying productivity that was developed using RSMeans Building Construction Cost Data, which is a source that is reliable, repeatable, and developed from consistent and accurate data sources. The metric was developed using labor and cost information from a sample of typical construction activities. The study results showed a slightly sporadic, but consistent productivity decline in both output per labor hour and per dollar cost from 1990 through 2008. Other metrics were selected from existing research studies and sources for a comparative analysis against the new metric, which revealed varying trends across metrics on the basis of varying input data and sources. The paper presents the new metric, which has value in that it allows construction professionals to analyze industry level productivity by means of a generally used and consistently published reference manual. DA - 2016/7// PY - 2016/7// DO - 10.1061/(asce)co.1943-7862.0001112 VL - 142 IS - 7 SP - SN - 1943-7862 KW - Productivity KW - Construction industry KW - Labor KW - Labor and personnel issues ER - TY - JOUR TI - Characterizing the biotransformation of sulfur-containing wastes in simulated landfill reactors AU - Sun, Wenjie AU - Sun, Mei AU - Barlaz, Morton A. T2 - WASTE MANAGEMENT AB - Landfills that accept municipal solid waste (MSW) in the U.S. may also accept a number of sulfur-containing wastes including residues from coal or MSW combustion, and construction and demolition (C&D) waste. Under anaerobic conditions that dominate landfills, microbially mediated processes can convert sulfate to hydrogen sulfide (H2S). The presence of H2S in landfill gas is problematic for several reasons including its low odor threshold, human toxicity, and corrosive nature. The objective of this study was to develop and demonstrate a laboratory-scale reactor method to measure the H2S production potential of a range of sulfur-containing wastes. The H2S production potential was measured in 8-L reactors that were filled with a mixture of the target waste, newsprint as a source of organic carbon required for microbial sulfate reduction, and leachate from decomposed residential MSW as an inoculum. Reactors were operated with and without N2 sparging through the reactors, which was designed to reduce H2S accumulation and toxicity. Both H2S and CH4 yields were consistently higher in reactors that were sparged with N2 although the magnitude of the effect varied. The laboratory-measured first order decay rate constants for H2S and CH4 production were used to estimate constants that were applicable in landfills. The estimated constants ranged from 0.11 yr−1 for C&D fines to 0.38 yr−1 for a mixed fly ash and bottom ash from MSW combustion. DA - 2016/7// PY - 2016/7// DO - 10.1016/j.wasman.2016.01.028 VL - 53 SP - 82-91 SN - 0956-053X KW - Sulfur-containing waste KW - Coal combustion residue KW - Ash KW - Hydrogen sulfide KW - Landfill ER - TY - JOUR TI - Can rapid assessments predict the biotic condition of restored streams? AU - Doll, B. AU - Jennings, G. AU - Spooner, J. AU - Penrose, D. AU - Usset, J. AU - Blackwell, J. AU - Fernandez, M. T2 - Water AB - Five rapid visual stream assessment methods were applied to 65 restored streams in North Carolina, and the results were correlated with measured macroinvertebrate community metrics to evaluate predictive ability. The USEPA Rapid Bioassessment Protocol (RBP), USDA Stream Visual Assessment Protocol (SVAP), Peterson’s Riparian Channel and Environmental Inventory (RCE), NCSU Eco-Geomorphological Assessment (EGA), and NCSU Stream Performance Assessment (SPA) were applied by teams with expertise in hydrology, fluvial geomorphology, and aquatic ecology. Predictions of most macroinvertebrate metrics were improved by re-weighting assessment variables using principal component analysis (PCA) and including watershed factors (e.g., size, slope, land use). The correlations of EGA, RCE, SPA and SVAP assessment results to macroinvertebrate metrics were most improved by variable re-weighting using PCA, while the correlations of RBP were most improved by adding watershed parameters. Akaike’s Information Criterion (AIC) indicates that PCA re-weighting including watershed parameters improves the predictor model for the total number of dominant EPT taxa more than using the sum total raw points for all five assessment methods. To demonstrate the application of the study results, a single-value index was generated for the RBP method using principal component regression (PCR) based on the EPT (Ephemeroptera, Plecoptera and Trichoptera) taxa metric. DA - 2016/// PY - 2016/// DO - 10.3390/w8040143 VL - 8 IS - 4 UR - http://www.mdpi.com/2073-4441/8/4/143 KW - rivers/streams KW - restoration KW - rapid habitat assessment KW - macroinvertebrates KW - watersheds ER - TY - JOUR TI - Agent-based modeling and evolutionary computation for disseminating public advisories about hazardous material emergencies AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman T2 - COMPUTERS ENVIRONMENT AND URBAN SYSTEMS AB - In the event of a large-scale disaster, an important aspect of humanitarian logistics is the distribution of information or warnings to the affected population. This research develops the problem formulation and solution approach for a specific routing for relief problem, in which warnings should be disseminated to an affected community, using public announcement systems mounted on emergency vehicles. The problem statement is formulated to maximize the number of individuals of a community who are protected. An evolutionary algorithm framework is developed by coupling an agent-based model with a variable-length genetic algorithm to route emergency vehicles. The dynamics of interactions among consumers, emergency vehicles, and the spatiotemporal trajectory of the hazard are simulated using an agent-based modeling approach, and a variable-length genetic algorithm approach selects routes to warn a maximum number of consumers before they are affected by the emergency. The example that is explored in this research is contamination of a water distribution network. A fleet of emergency vehicles is equipped with public address systems and is deployed to warn consumers to stop using contaminated water. The framework is demonstrated for an illustrative virtual city, Mesopolis. The results of the evolutionary algorithm framework are compared with two conventional routing optimization approaches, including a covering tour problem approach and a manual routing approach, for four contamination scenarios. The evolutionary algorithm can be applied to route emergency service vehicles to broadcast information for other emergencies, such as flash flooding, hazardous materials incidents, and severe weather. DA - 2016/5// PY - 2016/5// DO - 10.1016/j.compenvurbsys.2016.01.001 VL - 57 SP - 12-25 SN - 1873-7587 KW - Variable-length genetic algorithm KW - Agent-based model KW - Water distribution network KW - Water contamination events KW - Vehicle routing for relief problem KW - Covering tour problem KW - Complex adaptive system KW - Route alert ER - TY - JOUR TI - A two-level domain decomposition method with accurate interface conditions for the Helmholtz problem AU - Astaneh, Ali Vaziri AU - Guddati, Murthy N. T2 - INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING AB - Summary A new and efficient two‐level, non‐overlapping domain decomposition (DD) method is developed for the Helmholtz equation in the two Lagrange multiplier framework. The transmission conditions are designed by utilizing perfectly matched discrete layers (PMDLs), which are a more accurate representation of the exterior Dirichlet‐to‐Neumann map than the polynomial approximations used in the optimized Schwarz method. Another important ingredient affecting the convergence of a DD method, namely, the coarse space augmentation, is also revisited. Specifically, the widely successful approach based on plane waves is modified to that based on interface waves, defined directly on the subdomain boundaries, hence ensuring linear independence and facilitating the estimation of the optimal size for the coarse problem. The effectiveness of both PMDL‐based transmission conditions and interface‐wave‐based coarse space augmentation is illustrated with an array of numerical experiments that include comprehensive scalability studies with respect to frequency, mesh size and the number of subdomains. Copyright © 2015 John Wiley & Sons, Ltd. DA - 2016/7/6/ PY - 2016/7/6/ DO - 10.1002/nme.5164 VL - 107 IS - 1 SP - 74-90 SN - 1097-0207 KW - domain decomposition KW - non-overlapping KW - coarse spaces KW - absorbing interface condition KW - preconditioning KW - Helmholtz equation ER - TY - JOUR TI - A general characterization of the Hardy Cross method as sequential and multiprocess algorithms AU - Baugh, John AU - Liu, Shu T2 - STRUCTURES AB - The Hardy Cross method of moment distribution admits, for any problem, an entire family of distribution sequences. Intuitively, the method involves clamping the joints of beams and frames against rotation and balancing moments iteratively, whether consecutively, simultaneously, or in some combination of the two. We present common versions of the moment distribution algorithm and generalizations of them as both sequential and multiprocess algorithms, with the latter exhibiting the full range of asynchronous behavior allowed by the method. We prove, in the limit, that processes so defined converge to the same unique solution regardless of the distribution sequence or interleaving of steps. In defining the algorithms, we avoid overspecifying the order of computation initially using a sequential, nondeterministic process, and then more generally using concurrent processes. DA - 2016/5// PY - 2016/5// DO - 10.1016/j.istruc.2016.03.004 VL - 6 SP - 170-181 SN - 2352-0124 KW - Hardy Cross method KW - Moment distribution KW - Convergence KW - Algorithms KW - Concurrency ER - TY - JOUR TI - The extended shift model as a mechanistic-empirical approach to simulating confined permanent deformation of asphalt concrete in compression AU - Cao, Wei AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The extended shift model is presented as a convenient and effective mechanistic-empirical approach to simulating the densification induced permanent deformation of asphalt concrete under repeated loading. The model is composed of an incremental function that provides a reference deformation curve, and a shift factor function expressed in terms of three variables: reduced pulse time, confining pressure, and vertical stress. The model can be characterized by four triaxial stress sweep tests, and it fits in the state-of-practice frameworks to predict pavement rutting with improved reliability. DA - 2016/7/15/ PY - 2016/7/15/ DO - 10.1016/j.conbuildmat.2016.04.079 VL - 115 SP - 520-526 SN - 1879-0526 KW - Asphalt concrete KW - Permanent deformation KW - Mechanistic-empirical KW - Confining pressure KW - Repeated creep and recovery KW - Triaxial stress sweep test KW - Random loading ER - TY - JOUR TI - Tack Lifter for In Situ Measurement of Effective Emulsion Application Rates AU - Rawls, Mary AU - Im, Jeong Hyuk AU - Castorena, Cassie T2 - TRANSPORTATION RESEARCH RECORD AB - Emulsion application rates are critically important to the performance of pavement surface treatments and tack coats. In this study, the tack lifter was introduced as a means to measure in situ effective emulsion application rates at specific locations along the length of paving. The tack lifter is a simple, weighted device that is placed on top of a superabsorbent foam sheet applied to a paving surface. The absorbent sheet soaks up emulsion from the roadway surface to get a spot check of the amount of emulsion on the surface. The device measures the effective emulsion application rate on the paving surface, neglecting emulsions absorbed into the paving surface. Laboratory studies of emulsion application onto chip seal and hot-mix asphalt concrete surfaces demonstrate the ability of the tack lifter to capture the sensitivity of emulsion absorption to pavement surface texture. In addition, preliminary tack lifter field trial results are presented to demonstrate its use as a quality control field test. DA - 2016/// PY - 2016/// DO - 10.3141/2550-11 IS - 2550 SP - 80-88 SN - 2169-4052 ER - TY - JOUR TI - Parallel Evolutionary Algorithm for Designing Water Distribution Networks to Minimize Background Leakage AU - Shafiee, M. Ehsan AU - Berglund, Andrew AU - Berglund, Emily Zechman AU - Brill, E. Downey, Jr. AU - Mahinthakumar, G. T2 - Journal of Water Resources Planning and Management AB - Leaks in water distribution systems waste energy and water resources, increase damage to infrastructure, and may allow contamination of potable water. This research develops an evolutionary algorithm-based approach to minimize the cost of water loss, new infrastructure, and operations that reduce background leakage. A new design approach is introduced that minimizes capital and operational costs, including energy and water loss costs. Design decisions identify a combination of infrastructure improvements, including pipe replacement and valve installment, and operation rules for tanks and pumps. Solution approaches are developed to solve both a single-objective and multiobjective problem formulation. A genetic algorithm and a nondominated sorting genetic algorithm are implemented within a high-performance computing platform to select tank sizes, pump placement and operations, placement of pressure-reducing valves, and pipe diameters for replacing pipes. The evolutionary algorithm approaches identify solutions that minimize water loss due to leakage, operational costs, and capital costs, while maintaining pressure at nodes and operational feasibility for tanks and pumps. Solutions are compared to identify a recommended design. The framework is demonstrated to redesign a water distribution system for an illustrative case study, C-Town. DA - 2016/5// PY - 2016/5// DO - 10.1061/(asce)wr.1943-5452.0000601 VL - 142 IS - 5 SP - J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(ASCE)WR.1943-5452.0000601 DB - Crossref KW - Genetic algorithm KW - NSGA-II KW - Parallel programming KW - Water distribution system leak management KW - Battle of background leakage assessment for water networks ER - TY - JOUR TI - Improved inversion algorithms for near-surface characterization AU - Astaneh, Ali Vaziri AU - Guddati, Murthy N. T2 - GEOPHYSICAL JOURNAL INTERNATIONAL AB - Near-surface geophysical imaging is often performed by generating surface waves, and estimating the subsurface properties through inversion, that is, iteratively matching experimentally observed dispersion curves with predicted curves from a layered half-space model of the subsurface. Key to the effectiveness of inversion is the efficiency and accuracy of computing the dispersion curves and their derivatives. This paper presents improved methodologies for both dispersion curve and derivative computation. First, it is shown that the dispersion curves can be computed more efficiently by combining an unconventional complex-length finite element method (CFEM) to model the finite depth layers, with perfectly matched discrete layers (PMDL) to model the unbounded half-space. Second, based on analytical derivatives for theoretical dispersion curves, an approximate derivative is derived for the so-called effective dispersion curve for realistic geophysical surface response data. The new derivative computation has a smoothing effect on the computation of derivatives, in comparison with traditional finite difference (FD) approach, and results in faster convergence. In addition, while the computational cost of FD differentiation is proportional to the number of model parameters, the new differentiation formula has a computational cost that is almost independent of the number of model parameters. At the end, as confirmed by synthetic and real-life imaging examples, the combination of CFEM + PMDL for dispersion calculation and the new differentiation formula results in more accurate estimates of the subsurface characteristics than the traditional methods, at a small fraction of computational effort. DA - 2016/8// PY - 2016/8// DO - 10.1093/gji/ggw192 VL - 206 IS - 2 SP - 1410-1423 SN - 1365-246X KW - Inverse theory KW - Surface waves and free oscillations KW - Guided waves KW - Site effects KW - Wave propagation ER - TY - JOUR TI - Good modelling practice in applying computational fluid dynamics for WWTP modelling AU - Wicklein, E. AU - Batstone, D. J. AU - Ducoste, J. AU - Laurent, J. AU - Griborio, A. AU - Wicks, J. AU - Saunders, S. AU - Samstag, R. AU - Potier, O. AU - Nopens, I. AU - al., T2 - WATER SCIENCE AND TECHNOLOGY AB - Computational fluid dynamics (CFD) modelling in the wastewater treatment (WWT) field is continuing to grow and be used to solve increasingly complex problems. However, the future of CFD models and their value to the wastewater field are a function of their proper application and knowledge of their limits. As has been established for other types of wastewater modelling (i.e. biokinetic models), it is timely to define a good modelling practice (GMP) for wastewater CFD applications. An International Water Association (IWA) working group has been formed to investigate a variety of issues and challenges related to CFD modelling in water and WWT. This paper summarizes the recommendations for GMP of the IWA working group on CFD. The paper provides an overview of GMP and, though it is written for the wastewater application, is based on general CFD procedures. A forthcoming companion paper to provide specific details on modelling of individual wastewater components forms the next step of the working group. DA - 2016/3// PY - 2016/3// DO - 10.2166/wst.2015.565 VL - 73 IS - 5 SP - 969-982 SN - 1996-9732 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84959896875&partnerID=MN8TOARS KW - CFD KW - GMP KW - protocol KW - wastewater treatment ER - TY - JOUR TI - Determination of Biosolids Phosphorus Solubility and Its Relationship to Wastewater Treatment AU - Jameson, Molly AU - White, Jeffrey G. AU - Osmond, Deanna L. AU - Aziz, Tarek T2 - WATER ENVIRONMENT RESEARCH AB - ABSTRACT: In North Carolina (NC), biosolids land application rates governed by crop nitrogen (N) requirements typically surpass crop phosphorus (P) needs, increasing surface water pollution potential. The NC Department of Environmental Quality (NCDEQ) is considering P‐based biosolids application guidelines for some nutrient‐impaired watersheds using the P Loss Assessment Tool (PLAT), but important biosolids information is lacking: total P (TP), water‐extractable P (WEP), and percent water‐extractable P (PWEP). In each of three seasons, we sampled 28 biosolids from 26 participating water resource recovery facilities (WRRFs) and analyzed for TP, WEP, and percent dry matter (DM), from which PWEP and nonsoluble P were calculated. Based on descriptive statistics and an online survey of treatment processes, biosolids were divided into Class A‐alkaline, Class A‐heat, Class B‐slurry, and Class B‐cake. The average TP in Class A alkaline stabilized biosolids was more than five times less than the average of the other biosolids, 5.0 vs. 26.6 g/kg, respectively. Averaged over biosolids, WEP and PWEP were 1.4 g/kg and 5.0%, respectively. Stabilization processes appeared to reduce WEP substantially, so biosolids potential soluble‐P loss is low. Our data will allow PLAT to be used for biosolids P‐loss risk assessments. DA - 2016/7/1/ PY - 2016/7/1/ DO - 10.2175/106143016x14609975746406 VL - 88 IS - 7 SP - 602-610 SN - 1554-7531 KW - biosolids KW - phosphorus content KW - water extractable phosphorus KW - land application KW - stabilization processes KW - wastewater ER - TY - JOUR TI - Decomposition and carbon storage of hardwood and softwood branches in laboratory-scale landfills AU - Wang, Xiaoming AU - Barlaz, Morton A. T2 - Science of The Total Environment AB - Tree branches are an important component of yard waste disposed in U.S. municipal solid waste (MSW) landfills. The objective of this study was to characterize the anaerobic biodegradability of hardwood (HW) and softwood (SW) branches under simulated but optimized landfill conditions by measuring methane (CH4) yields, decay rates, the decomposition of cellulose, hemicellulose and organic carbon, as well as carbon storage factors (CSFs). Carbon conversions to CH4 and CO2 ranged from zero to 9.5% for SWs and 17.1 to 28.5% for HWs. When lipophilic or hydrophilic compounds present in some of the HW and SW samples were extracted, some samples showed increased biochemical methane potentials (BMPs). The average CH4 yield, carbon conversion, and CSF measured here, 59.4 mL CH4 g− 1 dry material, 13.9%, and 0.39 g carbon stored g− 1 dry material, respectively, represent reasonable values for use in greenhouse gas inventories in the absence of detailed wood type/species data for landfilled yard waste. DA - 2016/7// PY - 2016/7// DO - 10.1016/J.SCITOTENV.2016.03.091 VL - 557-558 SP - 355-362 J2 - Science of The Total Environment LA - en OP - SN - 0048-9697 UR - http://dx.doi.org/10.1016/J.SCITOTENV.2016.03.091 DB - Crossref KW - Landfills KW - Municipal solid waste KW - Hardwood and softwood branches KW - Anaerobic decomposition KW - Carbon storage ER - TY - JOUR TI - A comparison of methods to evaluate mass transport in damaged mortar AU - Ghasemzadeh, Farnam AU - Rashetnia, Reza AU - Smyl, Danny AU - Pour-Ghaz, Mohammad T2 - CEMENT & CONCRETE COMPOSITES AB - The service life of reinforced concrete (RC) structures is directly influenced by the transport properties of concrete. These transport properties are adversely affected by the presence of cracks. Therefore, for accurate service life estimation of RC structures the effect of cracks on mass transport needs to be understood and quantified. To quantify the effect of cracks, different measurement methods have been developed. In this paper, we compare different mass transport measurement methods for quantifying the effect of damage, and investigate which method is more sensitive and provides the most information on the effect of damage. In this work, damage was induced by freeze-thaw in mortar specimens. Mass transport properties were measured using electrical resistivity, rapid chloride permeability, sorptivity, drying, air permeability, water permeability, and desorption isotherm. The results indicate that the measured effect of damage depends on the mechanisms of transport used in the measurement technique, and therefore, different measurement techniques do not necessarily provide the same measure of the effect of damage. The water and air permeability are comparatively more sensitive to the presence of damage. DA - 2016/7// PY - 2016/7// DO - 10.1016/j.cemconcomp.2016.03.007 VL - 70 SP - 119-129 SN - 1873-393X KW - Cracking KW - Distributed damage KW - Durability KW - Freeze-thaw KW - Transport properties ER - TY - JOUR TI - Using neutron radiography to assess water absorption in air entrained mortar AU - Li, Wenting AU - Pour-Ghaz, Mohammad AU - Trtik, Pavel AU - Wyrzykowski, Mateusz AU - Muench, Beat AU - Lura, Pietro AU - Vontobel, Peter AU - Lehmann, Eberhard AU - Weiss, W. Jason T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Concrete highway and airport pavements are designed to be long lasting; however, some concrete pavements have shown premature deterioration at the cracks and joints. It has been hypothesized that one cause of this deterioration is associated with fluid ingress, especially in cases where those fluids contain deicing salts. This paper examines fluid ingress in mortar using a cross-sectional geometry that is similar to a typical concrete pavement joint. Time-dependent and spatial aspects of fluid ingress are examined using neutron radiography (NR), which was performed using the thermal neutron radiography station at the neutron spallation source at the Paul Scherrer Institut (PSI). Specifically, this paper examines the role of the initial relative humidity (or degree of saturation) and air content on the fluid ingress. The work indicates that the initial fluid ingress reaches a specific degree of saturation relatively rapidly, where the large capillary and gel pores appear to be filled in (commonly referred to as the nick point in sorption tests) and the entrapped and entrained air pores fill in more slowly over time. DA - 2016/5/1/ PY - 2016/5/1/ DO - 10.1016/j.conbuildmat.2016.02.001 VL - 110 SP - 98-105 SN - 1879-0526 KW - Concrete air content KW - Degree of saturation KW - Deicing salt KW - Neutron imaging KW - Neutron radiography KW - Pavement joint KW - Saw-cut KW - Unsaturated moisture ingress KW - Water absorption ER - TY - JOUR TI - Traffic restriction policies in an urban avenue: A methodological overview for a trade-off analysis of traffic and emission impacts using microsimulation AU - Fernandes, Paulo AU - Bandeira, Jorge M. AU - Fontes, Tania AU - Pereira, Sergio Ramos AU - Schroeder, Bastian J. AU - Rouphail, Nagui M. AU - Coelho, Margarida C. T2 - INTERNATIONAL JOURNAL OF SUSTAINABLE TRANSPORTATION AB - Urban traffic emissions have been increasing in recent years. To reverse that trend, restrictive traffic measures can be implemented to complement national policies. We have proposed a methodology to assess the impact of three restrictive traffic measures in an urban arterial by using a microsimulation model of traffic and emissions integrated platform. The analysis is extended to some alternative roads and to the overall network area. Traffic restriction measures provided average reductions of 45%, 47%, 35%, and 47% for CO2, CO, NOX, and HC, respectively, due to traffic being diverted to other roads. Nevertheless, increases of 91%, 99%, 55%, and 121% in CO2, CO, NOX, and HC, respectively, can be expected on alternative roads. DA - 2016/// PY - 2016/// DO - 10.1080/15568318.2014.885622 VL - 10 IS - 3 SP - 201-215 SN - 1556-8334 KW - Emissions KW - integrated platform KW - microscopic simulation KW - traffic restriction measures ER - TY - JOUR TI - The Consequences of Material Nonlinearity on the Axisymmetric Flexural Vibration Measurements for Estimating the Dynamic Elastic Modulus of Damaged Cement Based Materials AU - Rashetnia, Reza AU - Ghasemzadeh, Farnam AU - Pour-Ghaz, Mohammad T2 - JOURNAL OF ADVANCED CONCRETE TECHNOLOGY AB - Elastic modulus measurements are often required to evaluate the structural performance or to estimate the damage in cement-based materials. The axisymmetric flexural vibration (AFV) of a thick circular disk is a test method that can be used to estimate the dynamic elastic modulus of cement-based materials. Cement-based materials are inherently nonlinear materials and their nonlinearity increases with damage. The main objectives of this paper are to investigate the consequences of material nonlinearity on the AFV measurements, and to understand the implications of the change of material nonlinearity with damage on these measurements. In this work, experimental measurements are performed on mortar specimens damaged by freeze-thaw. Acoustic emission is used as a benchmark method to monitor and quantify the damage. DA - 2016/6// PY - 2016/6// DO - 10.3151/jact.14.287 VL - 14 IS - 6 SP - 287-298 SN - 1347-3913 ER - TY - JOUR TI - Substrate and electrode potential affect electrotrophic activity of inverted bioanodes AU - Hartline, Rosanna M. AU - Call, Douglas F. T2 - BIOELECTROCHEMISTRY AB - Electricity-consuming microbial communities can serve as biocathodic catalysts in microbial electrochemical technologies. Initiating their functionality, however, remains a challenge. One promising approach is the polarity inversion of bioanodes. The objective of this study was to examine the impact of bioanode substrate and electrode potentials on inverted electrotrophic activity. Bioanodes derived from domestic wastewater were operated at − 0.15 V or + 0.15 V (vs. standard hydrogen electrode) with either acetate or formate as the sole carbon source. After this enrichment phase, cathodic linear sweep voltammetry and polarization revealed that formate-enriched cultures consumed almost 20 times the current (− 3.0 ± 0.78 mA; − 100 ± 26 A/m3) than those established with acetate (− 0.16 ± 0.09 mA; − 5.2 ± 2.9 A/m3). The enrichment electrode potential had an appreciable impact for formate, but not acetate, adapted cultures, with the + 0.15 V enrichment generating twice the cathodic current of the − 0.15 V enrichment. The total charge consumed during cathodic polarization was comparable to the charge released during subsequent anodic polarization for the formate-adapted cultures, suggesting that these communities accumulated charge or generated reduced products that could be rapidly oxidized. These findings imply that it may be possible to optimize electrotrophic activity through specific bioanodic enrichment procedures. DA - 2016/8// PY - 2016/8// DO - 10.1016/j.bioelechem.2016.02.010 VL - 110 SP - 13-18 SN - 1878-562X KW - Biocathode KW - Microbial electrochemical systems KW - Electrode inversion KW - Electrotroph ER - TY - JOUR TI - Stochastic hydro-thermal scheduling optimization: An overview AU - Queiroz, Anderson Rodrigo T2 - RENEWABLE & SUSTAINABLE ENERGY REVIEWS AB - This paper presents an overview about the hydro-thermal scheduling problem. In an electrical power system power generators have to be scheduled over a time horizon in order to supply system demand. The scheduling problem consists in dispatching the available generators to meet the system electric load while minimizing the operational costs related to fuel and possible load curtailments. In a system with a large share of hydro generation, different from a thermal dominant power system, the uncertainty of water inflows play an important role in the decision-making process. In this setting the scheduling of generators has to be determined considering different future possibilities for water availability. Also, in the existence of a cascade system, the availability of water to produce electricity in hydro plants is influenced by decisions taken in upstream reservoirs. These issues complicate the hydro-thermal scheduling problem that often in the literature is modeled as a multi-stage stochastic program. In this paper we aim to give an overview about the main ideas behind this problem. We present model formulations, a solution technique, and point out to new developments related to this research. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.rser.2016.04.065 VL - 62 SP - 382-395 SN - 1879-0690 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84973354146&partnerID=MN8TOARS KW - Hydro-thermal scheduling KW - Multi-stage stochastic optimization KW - Renewable generation KW - Electrical power systems KW - Sampling-based decomposition algorithms ER - TY - JOUR TI - Retaining Wall Field Condition Inspection, Rating Analysis, and Condition Assessment AU - Butler, Cedrick J. AU - Gabr, Mohammed A. AU - Rasdorf, William AU - Findley, Daniel J. AU - Chang, Jeffrey C. AU - Hammit, Britton E. T2 - Journal of Performance of Constructed Facilities AB - In the past, highway retaining walls were assets that were often excluded from inventory programs and were regarded as noncritical or lost assets. With the recognition that wall failures may be detrimental to the roadway and the surroundings and may pose potential hazards to the safety of the public, several highway agencies have begun to incorporate retaining walls into their inventory and inspection programs. Work in this paper addresses the development of a system for the inventory and condition assessment of retaining walls serving various functions within the highway infrastructure. Critical elements of data collection are identified and a retaining wall information collection and assessment system (WICAS) is proposed. WICAS is designed such that data can be readily collected in the field. A condition assessment model is also proposed and is used to define a retaining wall rating metric. The rating system is designed so that those elements of a wall that are deemed to be in critical distress conditions are readily identified and not overlooked through the presentation of an overall average rating for the entire wall. DA - 2016/6// PY - 2016/6// DO - 10.1061/(asce)cf.1943-5509.0000785 VL - 30 IS - 3 SP - J2 - J. Perform. Constr. Facil. LA - en OP - SN - 0887-3828 1943-5509 UR - http://dx.doi.org/10.1061/(ASCE)CF.1943-5509.0000785 DB - Crossref KW - Retaining walls KW - Infrastructure asset management KW - Wall inventory KW - Asset inventory KW - Data collection KW - Rating system KW - Condition assessment ER - TY - JOUR TI - Public perceptions of water shortages, conservation behaviors, and support for water reuse in the US AU - Garcia-Cuerva, Laura AU - Berglund, Emily Z. AU - Binder, Andrew R. T2 - RESOURCES CONSERVATION AND RECYCLING 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 production of reclaimed water is 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. 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. Results demonstrate that a small percentage of the population is concerned about water shortages, the majority of the population practices some level of water conservation, and a substantial percentage of the population supports the use of reclaimed water. Climate, demographic variables, and financial incentives were tested for influence on attitudes and behaviors regarding water, including awareness, conservation, and support for water reuse. Sex, age, last monthly water bill, and location (as EPA region) showed no significant effect on the acceptance of water reuse, while ethnicity, education level, metro/non metro, and income showed significant effects. Drought conditions do not have a statistically significant effect on the number of reclaimed water supporters, but increase the number of respondents who are water concerned, the number of respondents who are the most active water conservers, and the number of respondents who limit their use of water for lawn and garden watering. Financial incentives influence the willingness of respondents to participate in water reuse programs, and a decrease in the monthly water bills increased the likelihood that respondents would participate in a reclaimed water program. Support for the use of reclaimed water for various applications ranked positively, on average, except for the application of water reuse for food crop irrigation and use of reclaimed water at respondents’ own residences. Results and conclusions of the survey can provide insight for implementing successful reclaimed water programs. DA - 2016/10// PY - 2016/10// DO - 10.1016/j.resconrec.2016.06.006 VL - 113 SP - 106-115 SN - 1879-0658 KW - Public opinion KW - Water conservation KW - Water reuse KW - Water shortage KW - Yuck factor KW - Survey ER - TY - JOUR TI - Planning for uncertainty: Use of structural equation modelling to determine the causal structure of time buffer allocation AU - Russell, M. M. AU - Liu, M. AU - Hsiang, S. M. T2 - Construction Management and Economics DA - 2016/// PY - 2016/// VL - 33 IS - 10 SP - 783-798 ER - TY - JOUR TI - Numerical evaluation of pavement design parameters for the fatigue cracking and rutting performance of asphalt pavements AU - Norouzi, Amirhossein AU - Kim, Dahae AU - Kim, Y. Richard T2 - MATERIALS AND STRUCTURES DA - 2016/9// PY - 2016/9// DO - 10.1617/s11527-015-0744-x VL - 49 IS - 9 SP - 3619-3634 SN - 1871-6873 KW - Asphalt KW - Pavement KW - Pavement design KW - Fatigue cracking KW - Rutting KW - LVECD program KW - Field condition ER - TY - JOUR TI - Nanoindentation and Atomic Force Microscopy Investigations of Asphalt Binder and Mastic AU - Veytskin, Yuriy AU - Bobko, Christopher AU - Castorena, Cassie T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - Nanoindentation techniques were implemented to calculate and interpret linear viscoelastic properties of asphalt binder and mastic through low-load spheroconical (blunt) nanoindentation. Experiments on three rolling thin-film oven (RTFO)–aged binders (two neat and one polymer modified) and 24 RTFO-aged mastics were implemented for reproducible creep indentations at ultra low loads. Creep compliance model parameters were extracted and used to determine dynamic modulus values for each material. Dynamic modulus values from nanoindentation were validated by using macroscopic dynamic shear rheometer (DSR) testing for two binders and two mastics (RTFO-aged). Atomic force microscopy (AFM) images of binder and mastic microstructure were obtained to shed insight on how microstructural phenomena relate to mechanical properties. The new results were combined with previously determined work of cohesion values for three binders and 30 mastics (RTFO-aged) made with the same materials to link microstructural phenomena with viscoelastic and cohesive properties of asphalt binder and mastic. The AFM results show microstructural changes occurring with the addition of mineral fillers that may relate to observed trends in nanoindentation viscoelasticity and cohesion data. Testing of binder and mastic properties through nanoindentation is an important step toward in situ testing of mastic in asphalt concrete, which is impossible using conventional macroscopic experimental methods. DA - 2016/6// PY - 2016/6// DO - 10.1061/(asce)mt.1943-5533.0001532 VL - 28 IS - 6 SP - SN - 1943-5533 KW - Nanoindentation KW - Atomic force microscopy (AFM) KW - Cohesion KW - Viscoelasticity KW - Asphalt KW - Binders KW - Mastics KW - Multiscale ER - TY - JOUR TI - Modeling a Discrete Wet-Dry Algorithm for Hurricane Storm Surge in Alloy AU - Baugh, John AU - Altuntas, Alper T2 - ABSTRACT STATE MACHINES, ALLOY, B, TLA, VDM, AND Z (ABZ 2016) AB - We describe an Alloy model that helps check the correctness of a discrete wet-dry algorithm used in a system for hurricane storm surge prediction. Derived from simplified physics and encoded with empirical rules, the algorithm operates on a finite element mesh to allow the propagation of overland flows. Our study is motivated by complex interactions between the algorithm and a recent performance enhancement to the system that involves mesh partitioning. We briefly outline our approach and describe safety properties of the extension, as well as directions for future work. DA - 2016/// PY - 2016/// DO - 10.1007/978-3-319-33600-8_18 VL - 9675 SP - 256-261 SN - 1611-3349 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84978698635&partnerID=MN8TOARS N1 - Lecture Notes in Computer Science 9675 RN - Lecture Notes in Computer Science 9675 ER - TY - JOUR TI - Integrated indicator to evaluate vehicle performance across: Safety, fuel efficiency and green domains AU - Torrao, G. AU - Fontes, T. AU - Coelho, M. AU - Rouphail, N. T2 - ACCIDENT ANALYSIS AND PREVENTION AB - In general, car manufacturers face trade-offs between safety, efficiency and environmental performance when choosing between mass, length, engine power, and fuel efficiency. Moreover, the information available to the consumers makes difficult to assess all these components at once, especially when aiming to compare vehicles across different categories and/or to compare vehicles in the same category but across different model years. The main objective of this research was to develop an integrated tool able to assess vehicle's performance simultaneously for safety and environmental domains, leading to the research output of a Safety, Fuel Efficiency and Green Emissions (SEG) indicator able to evaluate and rank vehicle's performance across those three domains. For this purpose, crash data was gathered in Porto (Portugal) for the period 2006-2010 (N=1374). The crash database was analyzed and crash severity prediction models were developed using advanced logistic regression models. Following, the methodology for the SEG indicator was established combining the vehicle's safety and the environmental evaluation into an integrated analysis. The obtained results for the SEG indicator do not show any trade-off between vehicle's safety, fuel consumption and emissions. The best performance was achieved for newer gasoline passenger vehicles (<5year) with a smaller engine size (<1400cm(3)). According to the SEG indicator, a vehicle with these characteristics can be recommended for a safety-conscious profile user, as well as for a user more interested in fuel economy and/or in green performance. On the other hand, for larger engine size vehicles (>2000cm(3)) the combined score for safety user profile was in average more satisfactory than for vehicles in the smaller engine size group (<1400cm(3)), which suggests that in general, larger vehicles may offer extra protection. The achieved results demonstrate that the developed SEG integrated methodology can be a helpful tool for consumers to evaluate their vehicle selection through different domains (safety, fuel efficiency and green emissions). Furthermore, SEG indicator allows the comparison of vehicles across different categories and vehicle model years. Hence, this research is intended to support the decision-making process for transportation policy, safety and sustainable mobility, providing insights not only to policy makers, but also for general public guidance. DA - 2016/7// PY - 2016/7// DO - 10.1016/j.aap.2016.03.008 VL - 92 SP - 153-167 SN - 1879-2057 KW - Integrated analysis KW - User profile KW - Crash severity KW - Vehicle performance ER - TY - JOUR TI - Influence of Confinement and Cementation Level on the Behavior of Microbial-Induced Calcite Precipitated Sands under Monotonic Drained Loading AU - Feng, K. AU - Montoya, B. M. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING 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 monotonic mechanical response of MICP cemented sand is systematically investigated using four cementation levels (untreated, lightly treated, moderately treated, and heavily treated) and three levels of effective confining pressure (100, 200, and 400 kPa). The results indicate that the stiffness, peak shear strength, and dilation increases with an increase in calcite content at a given effective confining pressure and the dilation is suppressed with an increase in effective confining pressure. This behavior is consistent with soil-like behavior; therefore, all the MICP soils presented herein are evaluated using critical-state soil mechanics and not an analogous fracture-mechanics framework. The experimental results also indicate that the improvement in peak and residual friction angles and initial elastic modulus, Ei, are dependent on the levels of cementation and effective confining pressure. The uniformity of MICP cementation in the laboratory specimens is also discussed. DA - 2016/1// PY - 2016/1// DO - 10.1061/(asce)gt.1943-5606.0001379 VL - 142 IS - 1 SP - SN - 1943-5606 KW - Cemented sand KW - Shear strength KW - Microbial-induced calcite precipitation KW - Sporosarcina pasteurii KW - Urea hydrolysis ER - TY - JOUR TI - Impact of Damping Scaling Factors on Direct Displacement-Based Design AU - Kong, Cuiyan AU - Kowalsky, Mervyn J. T2 - Earthquake Spectra AB - Damping scaling factors (DSFs) play an important role in direct displacement-based design (DDBD) as they provide a means to establish displacement response spectra for damping values beyond 5%. Response spectra for multiple damping values are needed for DDBD as the approach relies on equivalent linearization, expressed in the form of effective stiffness and equivalent viscous damping, to establish design forces for prescribed performance limit states. In the past, DSFs based on the Eurocode have been employed for DDBD; however, recent research has resulted in more robust DSF models. This paper examines the accuracy of the current DSF equation used in DDBD across the parameters that are important for structural design. A nonlinear regression analysis is performed based on the data obtained by the Rezaeian et al. (2014) model, and a base shear adjustment factor (SAF) is proposed for application to the DDBD base shear equation. DA - 2016/5// PY - 2016/5// DO - 10.1193/021815eqs031m VL - 32 IS - 2 SP - 843-859 J2 - Earthquake Spectra LA - en OP - SN - 8755-2930 UR - http://dx.doi.org/10.1193/021815EQS031M DB - Crossref ER - TY - JOUR TI - Identification of dominant source of errors in developing streamflow and groundwater projections under near-term climate change AU - Seo, S. B. AU - Sinha, T. AU - Mahinthakumar, G. AU - Sankarasubramanian, A. AU - Kumar, M. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract Uncertainties in projecting the changes in hydroclimatic variables (i.e., temperature and precipitation) under climate change partly arises from the inability of global circulation models (GCMs) in explaining the observed changes in hydrologic variables. Apart from the unexplained changes by GCMs, the process of customizing GCM projections to watershed scale through a model chain—spatial downscaling, temporal disaggregation, and hydrologic model—also introduces errors, thereby limiting the ability to explain the observed changes in hydrologic variability. Toward this, we first propose metrics for quantifying the errors arising from different steps in the model chain in explaining the observed changes in hydrologic variables (streamflow and groundwater). The proposed metrics are then evaluated using a detailed retrospective analyses in projecting the changes in streamflow and groundwater attributes in four target basins that span across a diverse hydroclimatic regimes over the U.S. Sunbelt. Our analyses focused on quantifying the dominant sources of errors in projecting the changes in eight hydrologic variables—mean and variability of seasonal streamflow, mean and variability of 3 day peak seasonal streamflow, mean and variability of 7 day low seasonal streamflow, and mean and standard deviation of groundwater depth—over four target basins using an Penn state Integrated Hydrologic Model (PIHM) between the period 1956–1980 and 1981–2005. Retrospective analyses show that small/humid (large/arid) basins show increased (reduced) uncertainty in projecting the changes in hydrologic attributes. Further, changes in error due to GCMs primarily account for the unexplained changes in mean and variability of seasonal streamflow. On the other hand, the changes in error due to temporal disaggregation and hydrologic model account for the inability to explain the observed changes in mean and variability of seasonal extremes. Thus, the proposed metrics provide insights on how the error in explaining the observed changes being propagated through the model under different hydroclimatic regimes. DA - 2016/7/16/ PY - 2016/7/16/ DO - 10.1002/2016jd025138 VL - 121 IS - 13 SP - 7652-7672 SN - 2169-8996 KW - error decomposition KW - climate change projection KW - dominant source of error KW - GCM ER - TY - JOUR TI - Quantifying fat, oil, and grease deposit formation kinetics AU - Iasmin, Mahbuba AU - Dean, Lisa O. AU - Ducoste, Joel J. T2 - WATER RESEARCH AB - Fat, oil, and grease (FOG) deposits formed in sanitary sewers are calcium-based saponified solids that are responsible for a significant number of nationwide sanitary sewer overflows (SSOs) across United States. In the current study, the kinetics of lab-based saponified solids were determined to understand the kinetics of FOG deposit formation in sewers for two types of fat (Canola and Beef Tallow) and two types of calcium sources (calcium chloride and calcium sulfate) under three pH (7 ± 0.5, 10 ± 0.5, and ≈14) and two temperature conditions (22 ± 0.5 and 45 ± 0.5 °C). The results of this study displayed quick reactions of a fraction of fats with calcium ions to form calcium based saponified solids. Results further showed that increased palmitic fatty acid content in source fats, the magnitude of the pH, and temperature significantly affect the FOG deposit formation and saponification rates. The experimental data of the kinetics were compared with two empirical models: a) Cotte saponification model and b) Foubert crystallization model and a mass-action based mechanistic model that included alkali driven hydrolysis of triglycerides. Results showed that the mass action based mechanistic model was able to predict changes in the rate of formation of saponified solids under the different experimental conditions compared to both empirical models. The mass-action based saponification model also revealed that the hydrolysis of Beef Tallow was slower compared to liquid Canola fat resulting in smaller quantities of saponified solids. This mechanistic saponification model, with its ability to track the saponified solids chemical precursors, may provide an initial framework to predict the spatial formation of FOG deposits in municipal sewers using system wide sewer collection modeling software. DA - 2016/1/1/ PY - 2016/1/1/ DO - 10.1016/j.watres.2015.11.009 VL - 88 SP - 786-795 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84947483809&partnerID=MN8TOARS KW - Fat, oil, and grease deposits KW - Saponification KW - Sanitary sewer overflows (SSOs) KW - Kinetics KW - Calcium based saponified solids ER - TY - JOUR TI - Performance Evaluation of Chip Seals for Higher Volume Roads Using Polymer-Modified Emulsions: Laboratory and Field Study in North Carolina AU - Im, Jeong Hyuk AU - Kim, Y. Richard T2 - JOURNAL OF TESTING AND EVALUATION AB - This paper presented a study to evaluate the performance of chip seals for higher traffic volume roads. The evaporation test, bitumen bond strength (BBS) test, and Vialit test were used to investigate curing and adhesive behavior. For the laboratory performance, the third-scale model mobile load simulator (MMLS3) was employed to test for aggregate retention, bleeding, and rutting performance. In field, a total of ten test sections were constructed on three different traffic volume roads using different materials and seal types. Some of the field samples were extracted and moved to the laboratory for performance testing. Also, the field sections were monitored to compare the field performance with the laboratory performance. The main findings presented in this paper were as follows: (1) the laboratory test results indicated that the use of polymer modified emulsions (PMEs) improved the chip seal performance in all areas, i.e., curing and adhesive behavior, aggregate retention, bleeding, and rutting; and (2) the field observations indicated that PME-A (styrene butadiene styrene (SBS) polymer-modified emulsion) performs the best of all the emulsions, regardless of seal type and traffic volume. DA - 2016/1// PY - 2016/1// DO - 10.1520/jte20140544 VL - 44 IS - 1 SP - 484-497 SN - 1945-7553 KW - chip seal KW - curing and adhesive behavior KW - performance properties KW - polymer-modified emulsion 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 - 2016/// PY - 2016/// IS - 2484 SP - 129-139 ER - TY - JOUR TI - Fenton Oxidation of Metsulfuron-Methyl with Application to Permeable Reactive Barriers AU - Abdul, Javeed M. AU - Vigneswaran, S. AU - Kandasamy, Jaya AU - Mahinthakumar, G. T2 - ENVIRONMENTAL MODELING & ASSESSMENT DA - 2016/1// PY - 2016/1// DO - 10.1007/s10666-015-9475-1 VL - 21 IS - 1 SP - 149-158 SN - 1573-2967 KW - Metsulfuron-methyl KW - Fenton oxidation KW - Column experiments KW - Numerical modeling KW - Permeable reactive barrier ER - TY - JOUR TI - Equivalent Viscous Damping Model for Short-Period Reinforced Concrete Bridges AU - Khan, Easa AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - Journal of Bridge Engineering AB - This paper investigates the effect of spectral shape (intensity and width of the constant acceleration region) and postyield stiffness ratio on equivalent viscous damping for short-period RC bridge columns (effective period<1s). The modified Takeda degrading stiffness hysteretic model, with parameters appropriate to bridge columns (often termed thin Takeda in the literature), is used for analysis. Insight regarding the importance of these parameters is provided, and a new equivalent viscous damping model is proposed that includes the effect of spectral shape and postyield stiffness ratio, as well as effective period and ductility. The proposed damping model is compared with two existing models. The results indicate that significant improvement is achieved in predicting the peak displacement using the proposed damping model when compared with existing models. DA - 2016/2// PY - 2016/2// DO - 10.1061/(asce)be.1943-5592.0000803 VL - 21 IS - 2 SP - 04015047 J2 - J. Bridge Eng. LA - en OP - SN - 1084-0702 1943-5592 UR - http://dx.doi.org/10.1061/(ASCE)BE.1943-5592.0000803 DB - Crossref KW - Equivalent viscous damping KW - Direct displacement-based seismic design KW - Short-period single-degree-of-freedom (SDOF) systems ER - TY - JOUR TI - Effects of Idle Time Restrictions on Excess Pollution from Construction Equipment AU - Abbasian-Hosseini, S. Alireza AU - Leming, Michael L. AU - Liu, Min T2 - Journal of Management in Engineering AB - Construction vehicles and equipment contribute to air pollution. To reduce pollution, numerous state and local jurisdictions limit the amount of time diesel engine vehicles or equipment can run at idle without shutting down. These restrictions vary widely indicating a need for improved understanding of the relationships between pollutant emissions and regulations establishing a maximum idle time in a construction setting. Previous studies have found that a reduction in operational efficiency will increase the amount of excess pollution, that is, the amount of pollution created in excess of that emitted by a construction operation under ideal conditions. Shutting down an engine can create a delay in re-entering the work stream and, therefore, reduce operational efficiency. In another study, the authors found that excess pollution would be minimal with a reasonably well-balanced, minimum or near minimum cost, construction equipment fleet composed of a single wheel loader (WL) working with different numbers of off-road dump trucks (OTs) on an independent soil-moving operation. This paper describes the results of an investigation using computer-based simulation techniques to determine the excess pollutant emissions for the same equipment conducting the same earthmoving operation, including the effects of a number of typical restrictions on maximum allowable idle times. Equipment emissions were based on previously published field data. DA - 2016/3// PY - 2016/3// DO - 10.1061/(asce)me.1943-5479.0000408 VL - 32 IS - 2 SP - 04015046 J2 - J. Manage. Eng. LA - en OP - SN - 0742-597X 1943-5479 UR - http://dx.doi.org/10.1061/(ASCE)ME.1943-5479.0000408 DB - Crossref KW - Construction equipment KW - Emissions KW - Air pollution KW - Greenhouse gas KW - Simulation KW - Diesel engine idling ER - TY - JOUR TI - A viscoplastic model for the confined permanent deformation of asphalt concrete in compression AU - Cao, Wei AU - Kim, Y. Richard T2 - MECHANICS OF MATERIALS AB - This paper presents a viscoplastic model for the permanent deformation behavior of asphalt concrete in compression. Triaxial repeated load permanent deformation (TRLPD) tests with haversine-shaped load pulses and rest periods were used in the experimental investigations as they are able to simulate real traffic loading patterns. For the first time, the viscoelastic–viscoplastic coupling phenomenon in asphalt concrete is illustrated using experimental data, which motivates the direct collecting and modeling of permanent deformation history in the present work instead of modeling the viscoelastic and viscoplastic responses in a separate and uncoupled fashion as in the traditional scheme. By applying a long rest period (100 s) to allow the viscoelastic deformation to recover sufficiently, the permanent strain data can be collected directly for viscoplastic model development. The proposed viscoplastic model features a convolution integral enclosed in Macaulay brackets. A single viscoplastic relaxation spectrum is assumed as the material's intrinsic property, and the nonlinear stress effects are captured through the variable E∞, which is the infinite modulus expressed as a logarithmic function of the triaxiality ratio. Material hardening (or softening) is described via the increase (or decrease) of the internal stress during loading (or unloading and rest period). The model was characterized using TRLPD test data at three levels of deviatoric stress and confining pressure. Finally, the calibrated model was verified by applying it to random loading tests conducted at other confining levels. The proposed model provides an efficient and convenient approach that is able to determine the material's macroscopic deformation as well as to capture the material's internal hardening/softening mechanisms. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.mechmat.2015.10.001 VL - 92 SP - 235-247 SN - 1872-7743 KW - Asphalt concrete KW - Permanent deformation KW - Viscoelastic-viscoplastic coupling KW - Viscoplasticity KW - Triaxial repeated load KW - Confining pressure ER - TY - JOUR TI - What impacts the performance of large-scale government projects? AU - Patanakul, Peerasit AU - Kwak, Young Hoon AU - Zwikael, Ofer AU - Liu, Min T2 - INTERNATIONAL JOURNAL OF PROJECT MANAGEMENT AB - Government projects and programs contribute to national growth at a great magnitude. However, records show that they are not well managed, even when project teams follow established project management principles. As a result, this study aimed at identifying key characteristics of government projects and programs, and recommending how they can be used to improve performance. This paper analyzed 39 public projects undertaken in the U.S., UK, and Australia and reviewed officially by the national audit offices and government agencies, including the Los Angeles Metro, London Heathrow's Terminal 5, and the fatal Australia's Homeowner Insulation Program. Based on this analysis the paper suggests six key characteristics, 17 practical recommendations, and six research propositions. These findings can support government project managers to utilize project management approaches according to project characteristics. This paper can support policy makers and government officials in improving the approaches for the management of government projects and programs DA - 2016/4// PY - 2016/4// DO - 10.1016/j.ijproman.2015.12.001 VL - 34 IS - 3 SP - 452-466 SN - 1873-4634 KW - Government projects KW - Characteristics KW - Performance ER - TY - JOUR TI - Fourier-finite element analysis of pavements under moving vehicular loading AU - Eslaminia, Mehran AU - Guddati, Murthy N. T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - With the goal of predicting progressive pavement distress (damage and rutting) under millions of cycles of moving vehicular loading, an efficient analysis framework is developed by combining the ideas of Fourier transform, finite element discretisation and time-scale separation. Using the simple observation of time-scale separation between evolution of pavement damage/rutting, temperature variation and traffic load variation, the analysis under millions of cycles is reduced to a few hundred analyses of stress and strain evolution under a single cycle of moving load. A new method called Fourier-finite element (FFE) method is proposed for each independent stress analysis. Essentially, Fourier analysis is used to eliminate the time dimension as well as the spatial dimension in the direction of traffic, reducing the problem to a set of two-dimensional problems, which are in turn solved using the finite element method (FEM). The FFE method is more efficient than direct three-dimensional (3D) FEM by orders of magnitude, but captures the 3D effects in an accurate manner. The FFE stress analysis technique is combined with time-scale separation-based ideas to develop a pavement performance modelling framework. A 20-year pavement simulation is presented to illustrate the efficiency of the proposed framework. DA - 2016/8/8/ PY - 2016/8/8/ DO - 10.1080/10298436.2015.1007237 VL - 17 IS - 7 SP - 602-614 SN - 1477-268X KW - Fourier transform KW - fatigue KW - pavement performance KW - continuum damage model KW - rutting KW - moving loads KW - finite element method ER - TY - JOUR TI - Efficient computation of dispersion curves for multilayered waveguides and half-spaces AU - Astaneh, Ali Vaziri AU - Guddati, Murthy N. T2 - COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING AB - Motivated by the need to compute dispersion curves for layered media in the contexts of geophysical inversion and nondestructive testing, a novel discretization approach, termed complex-length finite element method (CFEM), is developed and shown to be more efficient than the existing finite element approaches. The new approach is exponentially convergent based on two key features: unconventional stretching of the mesh into complex space and midpoint integration for evaluating the contribution matrices. For modeling the layered half-spaces of infinite depth, we couple CFEM with the method of perfectly matched discrete layers (PMDL) to minimize the errors due to mesh truncation. A number of numerical examples are used to investigate the efficiency of the proposed methods. It is shown that the suggested combination of CFEM and PMDL drastically reduces the number of elements, while requiring minor modifications to the existing finite element codes. It is concluded that the methods’ exponential convergence and sparse computation associated with linear finite elements, result in significant reduction in the overall computational cost. DA - 2016/3/1/ PY - 2016/3/1/ DO - 10.1016/j.cma.2015.11.019 VL - 300 SP - 27-46 SN - 1879-2138 KW - Guided waves KW - Surface waves KW - Layered media KW - Dispersion curve KW - Thin layer method KW - Perfectly matched layers ER - TY - JOUR TI - Development of a Transportation System Simulation Manual Framework From Theory to Practice AU - List, George AU - Mashayekhi, Mehdi AU - Bertini, Robert L. AU - Nevers, Brandon T2 - TRANSPORTATION RESEARCH RECORD AB - After several decades of advances, simulation has become an important tool in the modeling of transportation systems and is widely applied in practice. Guides have been created by organizations in several countries, and dozens of papers have been published in scientific journals on the theory and application of transport simulation; these works are aimed at guiding practitioners in the use of simulation tools. However, transport simulation still lacks a unified and comprehensive guide for use in practice. The lack of such a document leads to conflicts between modelers, agencies, and decision makers and allows inappropriate use of the models. The outcome is often inaccurate results, inefficient use of resources, and conflict. This paper reviews and analyzes the existing transportation simulation guides. It identifies gaps and limitations and proposes an outline for a comprehensive simulation manual that is based on stakeholder input. Review of the existing guidance documents reveals that almost all these documents focus on traffic operations, and they provide either broad guidelines for building simulation models or advice on using a specific software product. Other issues, particularly those related to topics such as safety assessments, environmental impacts, public transportation, pedestrians, bicycles, simulation algorithms, agent-based simulation, and multimodal simulation, are addressed in only a cursory fashion. This paper proposes a possible structure for a transportation system simulation manual that would cover the limitations and gaps in the existing literature. The proposed document would consist of five volumes: concepts, model building, verification and validation, results analysis, and case studies and supplementary materials. DA - 2016/// PY - 2016/// DO - 10.3141/2561-06 IS - 2561 SP - 45-52 SN - 2169-4052 ER - TY - JOUR TI - Determination of sources of organic matter in solid waste by analysis of phenolic copper oxide oxidation products of lignin AU - Cruz, F. B. AU - Osborne, J. AU - Barlaz, M. A. T2 - Journal of Environmental Engineering (New York, N.Y.) DA - 2016/// PY - 2016/// VL - 142 IS - 2 ER - TY - JOUR TI - Determination of 1,4-Dioxane in the Cape Fear River Watershed by Heated Purge-and-Trap Preconcentration and Gas Chromatography-Mass Spectrometry AU - Sun, Mei AU - Lopez-Velandia, Catalina AU - Knappe, Detlef R. U. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Recent U.S. Environmental Protection Agency data show that 1,4-dioxane is frequently detected in U.S. drinking water derived from both groundwater and surface water. 1,4-Dioxane is a likely human carcinogen, and an excess 10–6 cancer risk is associated with a drinking water concentration of 0.35 μg/L. To support 1,4-dioxane occurrence investigations, source identification and exposure assessment, a rapid and sensitive analytical method capable of quantifying 1,4-dioxane over a wide concentration range in a broad spectrum of aqueous matrices was developed. The fully automated method is based on heated purge-and-trap preconcentration and gas chromatography/mass spectrometry with selected-ion storage and has a reporting limit of 0.15 μg/L. Quantification of 1,4-dioxane was accomplished by isotope dilution using mass-labeled 1,4-dioxane-d8 as internal standard. Matrix spikes yielded recoveries of 86–115% in drinking water, groundwater, surface water, and wastewater treatment plant (WWTP) effluent. Also, 1,3-dioxane can be distinguished from 1,4-dioxane. The method was applied to investigate 1,4-dioxane occurrence and sources in the Cape Fear River watershed of North Carolina. 1,4-Dioxane concentrations ranged from <0.15 μg/L in nonimpacted surface water to 436 μg/L downstream of a WWTP discharge. In WWTP effluent, 1,4-dioxane concentrations varied widely, with a range of 1.3–2.7 μg/L in one community and 105–1,405 μg/L in another. Discharges from three municipal WWTPs were primarily responsible for elevated 1,4-dioxane concentrations in the Cape Fear River watershed. DA - 2016/3/1/ PY - 2016/3/1/ DO - 10.1021/acs.est.5b05875 VL - 50 IS - 5 SP - 2246-2254 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84959513702&partnerID=MN8TOARS ER - TY - JOUR TI - An enhanced linear regression-based building energy model (LRBEM plus ) for early design AU - Al Gharably, Maged AU - DeCarolis, Joseph F. AU - Ranjithan, S. Ranji T2 - JOURNAL OF BUILDING PERFORMANCE SIMULATION AB - The design community lacks simple, data-driven energy assessment tools to explore energy-efficient alternatives during the early stages of building design. A promising option is to utilize a whole building energy simulation engine (e.g. EnergyPlus) within a Monte Carlo simulation framework to develop a linear regression-based building energy model (LRBEM) that can predict idealized heating and cooling loads based on parameters relevant to early design. Previous work was limited to medium-sized US commercial office buildings with rectangular geometries. A key limitation is addressed in this paper by considering complex geometries. A reformulated model, LRBEM+, is developed and tested with a suite of building geometries that represent limiting cases. The resultant relative error between LRBEM+ and EnergyPlus is generally less than 10%. Furthermore, LRBEM+ correctly predicts the direction and magnitude of changes in heating and cooling loads in response to changes in the most influential early design parameters. DA - 2016/3// PY - 2016/3// DO - 10.1080/19401493.2015.1004108 VL - 9 IS - 2 SP - 115-133 SN - 1940-1507 KW - EnergyPlus KW - Monte Carlo simulation KW - multivariate regression KW - building geometry ER - TY - JOUR TI - Uplift Capacity of Plate Anchors in Saturated Clays: Analyses with Different Constitutive Models AU - Aghazadeh Ardebili, Zahra AU - Gabr, M. A. AU - Rahman, M. S. T2 - International Journal of Geomechanics AB - Evaluation of the uplift capacity of plate anchors in saturated clay is an important aspect in the design of offshore foundation systems of various structures. In most of the literature reviewed, simple constitutive models such as Tresca or Mohr–Coulomb (MC) have been used in evaluating the plates’ pullout capacity. There exists a need to study the pullout capacity of anchors using other advanced soil models and explore differences in computed behavior. In addition to the MC model, two other constitutive models are used herein to represent the soil behavior. These are Modified Cam-Clay and Soft Soil models. A series of finite-element analyses are performed using the three constitutive models. Undrained effective stress analyses are conducted to study the response of both strip and circular plate anchors in saturated soils. The capacities of plate anchors are assessed through the application of the displacement control approach. The effective stress parameters are correlated with the undrained shear strength, and Nc (dimensionless breakout factor) values from the three constitutive models are presented and compared with the lower bound solution, as well as with the data obtained from similar studies and experimental data available in the literature. Differences resulting from the characteristics of the three constitutive models are examined and discussed. DA - 2016/4// PY - 2016/4// DO - 10.1061/(asce)gm.1943-5622.0000518 VL - 16 IS - 2 SP - J2 - Int. J. Geomech. LA - en OP - SN - 1532-3641 1943-5622 UR - http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0000518 DB - Crossref KW - Constitutive models KW - Anchors KW - Capacity KW - FEM KW - Clays ER - TY - JOUR TI - SMT: An interface for localized storm surge modeling AU - Dyer, Tristan AU - Baugh, John T2 - ADVANCES IN ENGINEERING SOFTWARE AB - The devastation wrought by Hurricanes Katrina (2005), Ike (2008), and Sandy (2012) in recent years continues to underscore the need for better prediction and preparation in the face of storm surge and rising sea levels. Simulations of coastal flooding using physically based hydrodynamic codes like ADCIRC, while very accurate, are also computationally expensive, making them impractical for iterative design scenarios that seek to evaluate a range of countermeasures and possible failure points. We present a graphical user interface that supports local analysis of engineering design alternatives based on an exact reanalysis technique called subdomain modeling, an approach that substantially reduces the computational effort required. This interface, called the Subdomain Modeling Tool (SMT), streamlines the pre- and post-processing requirements of subdomain modeling by allowing modelers to extract regions of interest interactively and by organizing project data on the file system. Software design and implementation issues that make the approach practical, such as a novel range search algorithm, are presented. Descriptions of the overall methodology, software architecture, and performance results are given, along with a case study demonstrating its use. DA - 2016/2// PY - 2016/2// DO - 10.1016/j.advengsoft.2015.10.003 VL - 92 SP - 27-39 SN - 1873-5339 KW - Hurricane storm surge KW - Subdomain modeling KW - Finite element analysis KW - ADCIRC KW - Range search KW - Visualization ER - TY - JOUR TI - Real-world activity, fuel use, and emissions of diesel side-loader refuse trucks AU - Sandhu, Gurdas S. AU - Frey, H. Christopher AU - Bartelt-Hunt, Shannon AU - Jones, Elizabeth T2 - ATMOSPHERIC ENVIRONMENT AB - Diesel refuse trucks have the worst fuel economy of onroad highway vehicles. The real-world effectiveness of recently introduced emission controls during low speed and low engine load driving has not been verified for these vehicles. A portable emission measurement system (PEMS) was used to measure rates of fuel use and emissions on six side-loader refuse trucks. The objectives were to: (1) characterize activity, fuel use, and emissions; (2) evaluate variability between cycles and trucks; and (3) compare results with the MOVES emission factor model. Quality assured data cover 210,000 s and 550 miles of operation during which the trucks collected 4200 cans and 50 tons of waste material. The average fuel economy was 2.6 mpg. Trash collection contributed 70%–80% of total fuel use and emissions. The daily activity Operating Mode (OpMode) distribution and cycle average fuel use and emissions is different from previously used cycles such as Central Business District (CBD), New York Garbage Truck (NYGT), and William H. Martin (WHM). NOx emission rates for trucks with selective catalytic reduction were over 90% lower than those for trucks without. Similarly, trucks with diesel particulate filters had over 90% lower particulate matter (PM) emissions than trucks without. Compared to unloaded trucks, loaded truck averaged 18% lower fuel economy while NOx and PM emissions were higher by 65% and 16%, respectively. MOVES predicted values are highly correlated to empirical data; however, MOVES estimates are 37% lower for NOx and 300% higher for PM emission rates. The data presented here can be used to develop more representative cycles and improve emission factors for side-loader refuse trucks, which in turn can improve the accuracy of refuse truck emission inventories. DA - 2016/3// PY - 2016/3// DO - 10.1016/j.atmosenv.2016.01.014 VL - 129 SP - 98-104 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84957899410&partnerID=MN8TOARS KW - Diesel KW - Truck KW - Duty cycle KW - Exhaust emissions KW - Measurement KW - Nitrogen oxides KW - Particulate matter KW - Emission rates KW - Engine KW - MOVES KW - Weight ER - TY - JOUR TI - Improved Asset Management and Inventory Development through Sample Analysis and Vendor-Client Communication AU - Cunningham, Christopher M. AU - Findley, Daniel J. AU - Hovey, Kyle AU - Foley, Paul Burke AU - Smith, Jessica AU - Fowler, Tyler AU - Chang, Jeff AU - Arnold, Jonathan AU - Hummer, Joseph E. T2 - JOURNAL OF INFRASTRUCTURE SYSTEMS AB - This study compared output from mobile inventory data collection vehicles to manually collected data techniques with a focus on two-way communications primarily through the submission of a sample data set to be analyzed prior to the submission of a full data set. The interim submittal and feedback to the vendors based on that resulted in a marked improvement in data quality for 5 of the 28 assets studied. After feedback, it is apparent that highway data collection vendors can accurately locate the vast majority of assets, with the primary exception being those that are occluded by vehicles or surrounding landscaping, such as those assets in the median. Along with the locations of assets, vendors showed promise at collecting many of the feature descriptions such as asset type and condition. Many of the elements (location, type, etc.) for a particular asset type that created collection difficulty were only problematic for a particular vendor, which suggests that further improvements may be achieved through additional communication and more explicit definitions and examples by the contracting agency. Using measurement tolerances, the research team determined that measurements of height, grade, and azimuth were generally accurately obtained; however, measurements parallel to the direction of travel, such as offset and width, posed problems with accurate measurements. Last, the accuracy of data location was acceptable for finding assets in the field; however, many specific point features such as drop inlets or attenuators were not geo-located, but instead located from the vehicles position in the roadway. This appears to be standard practice for some vendors; therefore, if a specific location outside the roadway is desired, it should be clearly indicated in the instructions. Although mobile data collection is sufficient for most efforts, there is still room for improvement if more detailed location is necessary. DA - 2016/3// PY - 2016/3// DO - 10.1061/(asce)is.1943-555x.0000260 VL - 22 IS - 1 SP - SN - 1943-555X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84958576470&partnerID=MN8TOARS KW - Asset KW - Data collection KW - Mobile vehicle KW - Communication KW - Roadway ER - TY - JOUR TI - Enhanced Decision-Making Framework Using Reliability Concepts for Freeway Facilities AU - Hajbabaie, Ali AU - Aghdashi, Seyedbehzad AU - Rouphail, Nagui M. T2 - Journal of Transportation Engineering AB - This paper presents a decision-making framework based on a travel time reliability methodology developed under the U.S. Strategic Highway Research Program. Existing methods consider a set of predefined prevailing conditions for the analysis of freeway facilities as the base case. However, a reliability analysis accounts for multiple recurring and nonrecurring congestion sources to estimate the travel time distribution over a long time horizon. This approach considers variations in traffic demand levels, inclement weather conditions, and incidents that occur stochastically on a freeway facility. Several performance measures are defined based on the travel time distribution, which comprehensively cover the full range of operational conditions on the system. Based on the proposed decision-making framework, mobility strategies can be identified, evaluated, and improved. DA - 2016/4// PY - 2016/4// DO - 10.1061/(ASCE)TE.1943-5436.0000797 VL - 142 IS - 4 SP - 04016008 J2 - J. Transp. Eng. LA - en OP - SN - 0733-947X 1943-5436 UR - http://dx.doi.org/10.1061/(ASCE)TE.1943-5436.0000797 DB - Crossref KW - Travel time reliability KW - Decision-making framework KW - Highway capacity manual ER - TY - JOUR TI - Development of a ductile steel bridge substructure system AU - Fulmer, S.J. AU - Nau, J.M. AU - Kowalsky, M.J. AU - Marx, E.E. T2 - Journal of Constructional Steel Research AB - Described in this paper is the evaluation of a series of design concepts which attempt to improve the inelastic cyclic response of steel bridge substructures. The bridge system under consideration consists of hollow circular steel piles welded to steel cap beams. Described first is the motivation for the use of this type of structure, followed by a discussion of the research methods which include large scale reversed cyclic testing supplemented by finite element analysis. Next, the performance of the current as-built system, the fillet welded connection, is evaluated. This connection is shown to perform poorly with little inelastic deformation capacity prior to failure. A variety of alternative connections are then proposed and evaluated. These alternative connections include modified weld detailing and plastic hinge relocation approaches. Alternative weld detailing focuses on the complete joint penetration weld with reinforcing fillet welds. The plastic hinge relocation alternatives include a gusseted connection, a reduced column section, and the recently proposed grouted shear stud (GSS) connection. Alternative weld details produce only slight improvement in performance. Of the plastic hinge relocation concepts, the grouted shear stud (GSS) connection offers the most promising approach to improve inelastic cyclic response. DA - 2016/3// PY - 2016/3// DO - 10.1016/j.jcsr.2015.11.012 VL - 118 SP - 194-206 J2 - Journal of Constructional Steel Research LA - en OP - SN - 0143-974X UR - http://dx.doi.org/10.1016/j.jcsr.2015.11.012 DB - Crossref KW - Seismic KW - Bridge KW - Ductility KW - Hinge relocation KW - Welded connections ER - TY - JOUR TI - An experimental study on bond-type anchorages for carbon fiber-reinforced polymer cables AU - Mei, Kuihua AU - Seracino, Rudolf AU - Lv, Zhitao T2 - CONSTRUCTION AND BUILDING MATERIALS AB - It is well-known that the axial performance of carbon fiber-reinforced polymer (CFRP) cables is excellent, while the lateral compression and shear strengths are low. Thus, traditional steel cable anchorages cannot be used for CFRP cables due to the local crushing failure mode that would develop. Hence, a new bond-type anchorage filled with resin was proposed and five CFRP cables were fabricated with the new anchorage, which were tested statically to failure in tension. The tensile capacity, bond strength and pullout behavior of the new anchorage for CFRP cables were observed experimentally and are presented in this paper. The load–slip behavior of the new anchorage, sustained loading effect, load–deformation curves and the stress variation between tendons in the cables are also presented and discussed. Tensile fracture of the tendons was observed for all the five cables tested with efficiency coefficients all greater than 1.00. The tensile strength and overall performance achieved by the anchorage and CFRP cable system satisfied the design requirements for use in an experimental cable-stayed bridge constructed in China. DA - 2016/3/1/ PY - 2016/3/1/ DO - 10.1016/j.conbuildmat.2015.12.059 VL - 106 SP - 584-591 SN - 1879-0526 KW - CFRP cable KW - Anchorage KW - Tensile test KW - Slip KW - Pullout capacity KW - Bond strength ER - TY - JOUR TI - A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes AU - Sun, M. AU - Sun, W. J. AU - Barlaz, M. A. T2 - Science of the Total Environment DA - 2016/// PY - 2016/// VL - 551 SP - 23-31 ER - TY - JOUR TI - Vibration effects of nonclassically damped building-piping systems subjected to extreme loads AU - Ryu, Y. AU - Jung, W. AU - Ju, B. T2 - Shock and Vibration DA - 2016/// PY - 2016/// ER - TY - JOUR TI - Nanoindentation investigation of asphalt binder and mastic viscoelasticity AU - Veytskin, Yuriy AU - Bobko, Christopher AU - Castorena, Cassie T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - An exploratory nanoindentation technique for creep testing of two neat asphalt binders and one mastic at room temperature is developed, tested and verified. This work presents a new approach to obtain viscoelastic properties from low-load spherical (blunt) nanoindentation. Interconverted shear relaxation modulus mastercurves are determined from nanoindentation data. The magnitudes and trends of these mastercurves are found to be in reasonable agreement with Dynamic Shear Rheometer (DSR) results in a stiffness range associated with the range of time and temperature used in nanoindentation testing. Nanoindentation creep data is transformed to develop a mastercurve of dynamic modulus. The portion of this mastercurve corresponding to the frequency and temperature range included in nanoindentation testing demonstrates reasonable agreement with DSR results. These initial results suggest the potential to expand nanoindentation testing to forensic investigations involving testing of preserved asphalt binder and mastic components within field-extracted asphalt concrete composites. DA - 2016/4/20/ PY - 2016/4/20/ DO - 10.1080/10298436.2014.993393 VL - 17 IS - 4 SP - 363-376 SN - 1477-268X KW - nanotechnology KW - nanoindentation KW - micromechanics KW - viscoelasticity KW - loading rates KW - creep KW - asphalt KW - binders KW - mastics KW - multiscale ER - TY - JOUR TI - An algorithm for virtual fabrication of air voids in asphalt concrete AU - Dehghan Banadaki, Arash AU - Guddati, Murthy N. AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - Motivated by the virtual testing of asphalt concrete, the North Carolina State University research team has developed an algorithm to computationally generate air voids. After examining the X-ray tomographic images of real asphalt concrete microstructure, we concluded that the air void's shape and size are affected primarily by the surrounding local aggregate structure. Building on this observation, we developed an algorithm to generate random but representative air void configurations inside a given microstructure. By applying the algorithm to scanned aggregate structures, we show that the generated air voids not only look visually similar to actual air voids, but also are effective in capturing modulus reduction. The algorithm is included in a virtual aggregate structure generation framework, resulting in a streamlined virtual fabrication procedure for asphalt concrete that can qualitatively capture the effects of accelerated degradation due to the presence of air voids. DA - 2016/3/15/ PY - 2016/3/15/ DO - 10.1080/10298436.2014.979822 VL - 17 IS - 3 SP - 225-232 SN - 1477-268X KW - asphalt concrete KW - air void KW - X-ray tomography KW - fatigue performance KW - virtual fabrication ER - TY - JOUR TI - A double-sweeping preconditioner for the Helmholtz equation AU - Eslaminia, Mehran AU - Guddati, Murthy N. T2 - JOURNAL OF COMPUTATIONAL PHYSICS AB - A new preconditioner is developed to increase the efficiency of iterative solution of the Helmholtz equation. The key idea of the proposed preconditioner is to split the domain of interest into smaller subdomains and sequentially approximate the forward and backward components of the solution. The sequential solution is facilitated by approximate interface conditions that ignore the effect of multiple reflections. The efficiency of the proposed method is tested using various 2-D heterogeneous media. We observe that the proposed preconditioner results in good convergence, with number of iterations growing very slowly with increasing frequency. We also note that the mesh size and number of subdomains do not affect the convergence rate. Finally, we find that the overall computational time is much smaller than that of the sweeping preconditioner. DA - 2016/6/1/ PY - 2016/6/1/ DO - 10.1016/j.jcp.2016.03.022 VL - 314 SP - 800-823 SN - 1090-2716 KW - Preconditioner KW - Helmholtz equation KW - Iterative solver KW - Amplitude-preserving propagator ER - TY - JOUR TI - A Modular Colored Stochastic Petri Net for Modeling and Analysis of Signalized Intersections AU - List, George F. AU - Mashayekhi, Mehdi T2 - IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS AB - The dynamic behavior of traffic lights regulating a network of intersections can be viewed as a complex discrete-event system that can be modeled and controlled by Petri nets. In this paper, a bilayer signalized control method is presented. In the lower layer, a colored stochastic Petri net controls the signal indication displays and stage transitions. In the upper layer, a supervisory logic layer decides which stage should be serviced next. The proposed model increases modularity, reduces complexity, and, more importantly, is capable of being used to implement various signal control strategies. The method is used to implement four different control strategies: pretimed control, fully actuated control, semiactuated control, and random stage selection (as a benchmark) in the context of a signalized traffic network containing six intersections. Extensibility and future potential research to further enhance the proposed method are discussed and proposed at the end. DA - 2016/3// PY - 2016/3// DO - 10.1109/tits.2015.2483324 VL - 17 IS - 3 SP - 701-713 SN - 1558-0016 KW - Petri nets (PNs) KW - modular KW - discrete-event systems KW - traffic signals ER -