TY - JOUR TI - Impact of material electrical conductivity on the microbial community structure in anaerobic digesters T2 - Abstracts of Papers of the American Chemical Society DA - 2018/// PY - 2018/// UR - https://publons.com/wos-op/publon/55232988/ ER - TY - JOUR TI - Motivators for treated wastewater acceptance across developed and developing contexts AU - Rice, Jacelyn AU - Stotts, Rhian AU - Wutich, Amber AU - White, Dave AU - Maupin, Jonathan AU - Brewis, Alexandra T2 - Journal of Water, Sanitation and Hygiene for Development AB - Abstract As water scarcity increases, we must turn to underutilized sources such as treated wastewater. While work has been done on barriers to public acceptance, less work has been undertaken to explore motivations that may incentivize adoption of this potential water source. Using data collected from respondents in four global sites (in Guatemala, Fiji, New Zealand, and Spain), we (1) analyzed how four motivators (cost, current and future water shortages, and ecological conservation) influenced respondents' willingness to use treated wastewater and (2) examined if respondents' willingness varied across contexts based on the level of wastewater treatment available. Despite a focus in previous research on the role of reducing cost and providing economic incentives for wastewater reuse adoption, cost was broadly the least motivating factor while ecological conservation and future water shortages were the two strongest motivators across all sites. Additionally, respondents in sites with low levels of wastewater technology were more likely to express a willingness to use treated wastewater given any motivator. DA - 2018/// PY - 2018/// DO - 10.2166/washdev.2018.285 VL - 9 IS - 1 SP - 1-6 ER - TY - JOUR TI - Modeled De Facto Reuse and Contaminants of Emerging Concern in Drinking Water Source Waters AU - Nguyen, Thuy AU - Westerhoff, Paul AU - Furlong, Edward T. AU - Kolpin, Dana W. AU - Batt, Angela L. AU - Mash, Heath E. AU - Schenck, Kathleen M. AU - Boone, J. Scott AU - Rice, Jacelyn AU - Glassmeyer, Susan T. T2 - Journal - American Water Works Association AB - De facto reuse is the percentage of drinking water treatment plant (DWTP) intake potentially composed of effluent discharged from upstream wastewater treatment plants (WWTPs). Results from grab samples and a De Facto Reuse in our Nation's Consumable Supply (DRINCS) geospatial watershed model were used to quantify contaminants of emerging concern (CECs) concentrations at DWTP intakes to qualitatively compare exposure risks obtained by the two approaches. Between nine and 71 CECs were detected in grab samples. The number of upstream WWTP discharges ranged from 0 to >1,000; comparative de facto reuse results from DRINCS ranged from <0.1 to 13% during average flow and >80% during lower streamflows. Correlation between chemicals detected and DRINCS modeling results were observed, particularly DWTPs withdrawing from midsize water bodies. This comparison advances the utility of DRINCS to identify locations of DWTPs for future CEC sampling and treatment technology testing. DA - 2018/// PY - 2018/// DO - 10.1002/awwa.1052 VL - 110 IS - 4 SP - E2-E18 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85045137820&partnerID=MN8TOARS ER - TY - CONF TI - Soil behavior and mineral composition of bio-cemented sands in the presence of calcium and magnesium ions AU - Montoya, B.M. AU - Safavizadeh, S.S. AU - Gabr, M.A. T2 - B2G C2 - 2018/// C3 - Proceedings: B2G CY - Atlanta, GA DA - 2018/// PY - 2018/9// ER - TY - CONF TI - Deformation-based versus Limit Equilibrium Analyses to Assess the Effect of Repeated Rise and Fall of Water Level on the Stability of Princeville Levee AU - Jadid, R. AU - Montoya, B.M. AU - Bennett, V. AU - Gabr, M. T2 - Dam Safety 2018, Association of State Dam Safety Officials (ASDSO) C2 - 2018/// C3 - Proceedings from Dam Safety 2018, Association of State Dam Safety Officials (ASDSO) CY - Seattle, WA DA - 2018/// PY - 2018/9// ER - TY - JOUR TI - Debonding of Microbially Induced Carbonate Precipitation-Stabilized Sand under Axial Compression and Impinging Jet AU - Do, J. AU - Montoya, B. AU - Gabr, M. T2 - 2018 World Congress on Advances in Civil, Environmental, and Material Research DA - 2018/// PY - 2018/// ER - TY - CONF TI - Performance Limit States of Reinforced Concrete-Filled Steel Tube Drilled Shafts AU - Aguirre-Realpe, Diego A. AU - Kowalsky, M.J. AU - Nau, J.M. AU - Gabr, M.A. T2 - Eleventh U.S. National Conference on Earthquake Engineering Integrating Science, Engineering & Policy C2 - 2018/// C3 - Eleventh U.S. National Conference on Earthquake Engineering Integrating Science, Engineering & Policy CY - Los Angeles, California DA - 2018/// PY - 2018/// ER - TY - JOUR TI - A Simplified Direct Shear Testing Procedure to Evaluate Unsaturated Shear Strength AU - Tang, Chien-Ting AU - Borden, Roy H. AU - Gabr, Mohammed A. T2 - Geotechnical Testing Journal AB - The work in this paper presents a simplified and expedient procedure to evaluate unsaturated shear strength using conventional direct shear testing with tensiometer-measured suctions. Two types of residual soils are utilized in this testing program. These are classified as elastic silt (MH) and silt (ML) and were obtained from a test site in Greensboro, North Carolina. Unsaturated triaxial tests were performed to provide reference values for comparison with the measured values from the proposed direct shear testing approach. Both single stage and multistage triaxial tests were performed, and an insignificant difference in the peak stress from both approaches was found. The total cohesion intercept was used to represent the strength contribution of the matric suction in order to normalize the effect of the confining pressure. The applicability of the simplified expedient procedure in assessing shear strength of residual soils used herein was demonstrated based on the total cohesion intercepts obtained from both testing approaches. The results from the proposed approach were very similar to those obtained from the unsaturated triaxial compression tests. DA - 2018/1/5/ PY - 2018/1/5/ DO - 10.1520/GTJ20150161 VL - 41 IS - 2 SP - 20150161 J2 - Geotech. Test. J. LA - en OP - SN - 0149-6115 UR - http://dx.doi.org/10.1520/GTJ20150161 DB - Crossref ER - TY - JOUR TI - Solar generation, storage, and electric vehicles in power grids: Challenges and solutions with coordinated control at the residential level AU - Hafiz, F. AU - De Queiroz, A.R. AU - Husain, I. T2 - IEEE Electrification Magazine AB - Solar energy is an abundant renewable energy source that is available all around the world every day. Each hour, the solar rays that reach our Earth (if properly converted to electricity and other forms of energy) represent more than the total energy consumption of the entire human race over the course of one year. Wind energy is another important renewable resource available in large amounts every day. These two renewable energy sources are attracting significant investment as countries seek technology cost reductions to aid sustainability. DA - 2018/// PY - 2018/// DO - 10.1109/MELE.2018.2871319 VL - 6 IS - 4 SP - 83-90 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85057761435&partnerID=MN8TOARS ER - TY - CONF TI - Weight limits in the DEA benchmarking model for Brazilian electricity distribution companies AU - Medeiros, G.O.S. AU - Lima, J.W.M. AU - Lima, L.M.M. AU - De Queiroz, A.R. AB - The periodic tariff review process is applied to tariff control and regulation of electrical energy distribution system. In Brazil, the method used to obtain the efficient operational cost (OPEX) is a benchmarking technique based in linear programming called Data Envelopment Analysis (DEA). This paper presents an analysis of the DEA applied to the Brazilian distribution companies focusing on the weight restrictions incorporated by the regulatory agency. An alternative technique, the Ratio-based Efficiency Analysis (REA) is also applied to the analysis to provide additional information regarding the performance of DEA coupled with weight restrictions for the Brazilian case. C2 - 2018/// C3 - SBSE 2018 - 7th Brazilian Electrical Systems Symposium DA - 2018/// DO - 10.1109/SBSE.2018.8395921 SP - 1-6 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85050233786&partnerID=MN8TOARS ER - TY - JOUR TI - Proposed method for contracting of wind-photovoltaic projects connected to the Brazilian electric system using multiobjective programming AU - Aquila, Giancarlo AU - Rocha, Luiz Célio Souza AU - Oliveira Pamplona, Edson AU - Queiroz, Anderson Rodrigo AU - Junior, Paulo Rotela AU - Balestrassi, Pedro Paulo AU - Fonseca, Marcelo Nunes T2 - Renewable and Sustainable Energy Reviews AB - Owing to the wind and photovoltaic (PV) potential in Brazil, the country has recently seen increased exploration into the construction of wind-PV hybrid plants. However, as specific criteria for contracting this type of project have not yet been developed, this paper presents a model to assist the government in contracting projects that maximize the socioeconomic well-being of the Brazilian electricity sector. For this, multiobjective programming is used to simultaneously handle two objective functions—maximally reducing emission density and minimizing the levelized cost of electricity (LCOE)—with the aid of the mixture arrangement technique. In this respect, the optimization method called normal boundary intersection (NBI) is applied to solve the multiobjective problem and construct the Pareto frontier. Additionally, a metric based on the ratio between entropy and the global percentage error (GPE) is used to identify the optimal Pareto solution. The model was applied to determine optimal configurations for wind-PV powerplants in twelve Brazilian cities, and the results obtained reveal the capacity of the model to indicate the optimum configuration according to the wind and PV potential of each city. DA - 2018/12// PY - 2018/12// DO - 10.1016/j.rser.2018.08.054 VL - 97 SP - 377-389 UR - https://doi.org/10.1016/j.rser.2018.08.054 ER - TY - CONF TI - Cost-benefit assessment challenges for a smart distribution system: A case study AU - Sun, Lisha AU - Thomas, J. AU - Singh, S. AU - Li, D. AU - Baran, Mesut AU - Lubkeman, David AU - Decarolis, J. AU - Queiroz, Anderson Rodrigo De AU - White, L. AU - Watts, S. AB - The FREEDM system is a technology for a smarter and resilient distribution system that facilitates a higher level of distributed energy resource (DER) integration by offering effective voltage regulation, reactive power compensation and real time monitoring and control. This paper provides a framework for conducting a cost-benefit analysis for such a smart distribution system. The method first identifies the benefits, and then quantifies and monetizes them. OpenDSS time-series based power flow simulation is used to quantify the benefits accurately. The costs associated with the new components of the system are estimated based on prototype units. A cost-benefit analysis is adopted to identify the scenarios where employing such a system by a utility becomes economically attractive. C2 - 2018/// C3 - IEEE Power and Energy Society General Meeting DA - 2018/// DO - 10.1109/PESGM.2017.8274167 VL - 2018-January SP - 1-5 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85046337981&partnerID=MN8TOARS ER - TY - CONF TI - Coordinated control of PEV and PV-based storage system under generation and load uncertainties AU - Hafiz, F. AU - De Queiroz, A.R. AU - Husain, I. AB - Energy storage is an attractive choice for deployment in residential and commercial applications aiming to ensure proper utilization of solar photovoltaic (PV) power generation. Energy storage can be controlled and coordinated with PV generation to satisfy electricity demand and minimize electricity purchases from the grid. However, PV generation and load profile depend on the real-time weather condition and the usage by the owners. Thus, PV generation and demand uncertainties need to be considered when designing a control scheme for the PV-based storage system. Another resource at the residential level is theplug-in electric vehicle (PEV) which has a bi-directional capability and can reduce the electric power draw from the grid during peak hours. Therefore, the charging and discharging routines of the PEV can be controlled to achieve optimal economic benefits. In this paper, a method of coordinated optimal control between PV-based storage and PEV storage is proposed considering the stochastic nature of solar PV generation and load demand. The stochastic dual dynamic programming (SDDP) algorithm is employed to optimize the charge/discharge profiles of PV-based energy storage and PEV storage to minimize the overall cost of the daily household electricity purchase from the grid. Simulation analysis is performed in order to show the advantage of coordinated control compared to the other control strategies. C2 - 2018/// C3 - 2018 IEEE Industry Applications Society Annual Meeting, IAS 2018 DA - 2018/// DO - 10.1109/IAS.2018.8544636 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85057766366&partnerID=MN8TOARS ER - TY - JOUR TI - Laboratory investigation on chemical and rheological properties of bio-asphalt binders incorporating waste cooking oil AU - Wang, Chao AU - Xue, Lei AU - Xie, Wei AU - You, Zhanping AU - Yang, Xu T2 - Construction and Building Materials AB - Recent efforts are being conducted to develop alternative asphalt binders from various bio-mass resources for future flexible pavements construction due to their renewability and the increasing costs of conventional petroleum-based asphalt. The objective of this paper is to investigate the potential of using the waste cooking oil (WCO) based bio-oil as a modifier for petroleum based neat asphalt binder and Styrene-Butadiene-Styrene (SBS) modified binder by means of chemical and rheological approaches. A series of tests were conducted for such purpose, including the infrared spectroscopy test, frequency sweep rheological test, multiple stress creep recovery test, and linear amplitude sweep test. The infrared spectroscopy results indicate identical chemical functional groups between the bio-oil and the petroleum asphalt binder though acid, ether, ester and alcohol compounds were also observed within the bio-oil. The bio-oil modified binders display increased carbonyl index with increasing the bio-oil percent weight whereas the sulfoxide index almost exhibits the same level as that of the control asphalt. Frequency sweep tests show that the bio-oil addition obviously decreased the binder stiffness according to the dynamic shear modulus master curve. Due to this softening effect from the bio-oil modifier, the weakened rutting resistance of bio-binders are demonstrated for both neat and SBS binders at the high temperature range. The fatigue life of bio-binders at intermediate temperature under cyclic fatigue loading are found to be significantly improved by increasing bio-oil content but the binder yield energy simultaneously decreased. It can be preliminarily concluded that the WCO based bio-oil tested in this study could be used as a potential bio-modifier to produce a sustainable asphalt binder. DA - 2018/4// PY - 2018/4// DO - 10.1016/j.conbuildmat.2018.02.038 VL - 167 SP - 348-358 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/j.conbuildmat.2018.02.038 DB - Crossref ER - TY - CONF TI - Analysis of multiple solutions in the calculus of firm energy AU - Faria, V.A.D. AU - De Queiroz, A.R. AU - Lima, L.M.M. AU - Lima, J.W.M. AB - This paper uses a linear optimization model to investigate the calculus of firm energy rights of hydro power plants in Brazil. The firm energy values influence directly in the remuneration of the Brazilian hydro plants, besides that, linear optimization models are widely used in the literature for studies of firm energy. In this work, the authors show that the linear optimization models used in the calculus of firm energy rights can present multiple optimal solutions, more specifically, that it is possible to solve the problem to optimality and find different individual firm energy values, this behavior is not desirable in the firm energy models since this parameter impacts directly in the remuneration of the hydro plants. Using data from the Brazilian Electrical System the authors could determine the intensity of these multiple optimal solutions in an example, the results show that the phenomenon is relevant, influencing significantly in the firm energy values. C2 - 2018/// C3 - SBSE 2018 - 7th Brazilian Electrical Systems Symposium DA - 2018/// DO - 10.1109/SBSE.2018.8395694 SP - 1-6 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85050202742&partnerID=MN8TOARS ER - TY - CONF TI - Seismic Assessment of Unreinforced Masonry Houses in the Groningen Area AU - Moratti, M. AU - Gaia, F. AU - Martini, S. AU - Tomasi, A. AU - Casotto, C. AU - Tsioli, C. AU - Grecchi, G. AU - Ozcebe, S. AU - Calvi, G.M. AU - Den Hertog, D. AU - Calvi, P.M. AU - Proestos, G.T. T2 - 16th European Conference on Earthquake Engineering C2 - 2018/6/18/ C3 - 16th European Conference on Earthquake Engineering CY - Thessaloniki, Greece DA - 2018/6/18/ PY - 2018/6/18/ ER - TY - CONF TI - The Seismic Assessment of Unreinforced Masonry Church Inventories in the Groningen Area AU - Moratti, M. AU - Gaia, F. AU - Martini, S. AU - Tsioli, C. AU - Grecchi, G. AU - Calvi, G.M. AU - Den Hertog, D. AU - Calvi, P.M. AU - Proestos, G.T. T2 - 16th European Conference on Earthquake Engineering C2 - 2018/6/18/ C3 - 16th European Conference on Earthquake Engineering CY - Thessaloniki, Greece DA - 2018/6/18/ PY - 2018/6/18/ ER - TY - JOUR TI - ­Maximum Shear Capacity of Reinforced Concrete Members AU - Proestos, Giorgio T. AU - Bentz, Evan C. AU - Collins, Michael 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 - 2018/9// PY - 2018/9// DO - 10.14359/51702252 VL - 115 IS - 5 SP - 1463-1473 OP - SN - 0889-3241 UR - http://dx.doi.org/10.14359/51702252 DB - Crossref KW - deep beams KW - high strength KW - maximum shear strength KW - shear KW - slender beams KW - transfer girder ER - TY - CONF TI - Towards the development of direct crack-based assessment of structures AU - Calvi, P.M. AU - Proestos, G.T. AU - Ruggiero, D.M. C2 - 2018/// C3 - American Concrete Institute, ACI Special Publication DA - 2018/// VL - 2018-March SP - 141-160 M1 - SP 328 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85064955408&partnerID=MN8TOARS ER - TY - CONF TI - Advanced nonlinear finite element modelling of reinforced concrete bridge piers AU - Bruun, E.P.G. AU - Kuan, A. AU - Proestos, G.T. AU - Bentz, E.C. AU - Collins, M.P. C2 - 2018/// C3 - Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges - Proceedings of the 9th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2018 DA - 2018/// SP - 1231-1238 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85067006371&partnerID=MN8TOARS ER - TY - JOUR TI - Sorption of Perfluoroalkyl Acids to Fresh and Aged Nanoscale Zerovalent Iron Particles AU - Zhang, Y. AU - Zhi, Y. AU - Liu, J. AU - Ghoshal, S. T2 - Environmental Science and Technology AB - The sorption of perfluoroalkyl acids (PFAAs), particularly perfluorooctanesulfonic acid (PFOS), to freshly synthesized nanoscale zerovalent iron (nZVI) and aged (oxidized) and sulfidated nZVI, was investigated under anaerobic conditions. The sorption of PFAAs to nZVI was 2–4 orders of magnitude higher than what has been reported for sediments, soils, and iron oxides. The hydrophobicity of the perfluorocarbon chain dominated the sorption, although FTIR spectra indicated specific interactions between sulfonate and carboxylate head groups and nZVI. The contributions from electrostatic interactions depended on the surface charge and pH. Humic acids influenced sorption only at concentrations above 50 mg/L. nZVI aged in deoxygenated water up to 95 days showed similar sorption isotherms for PFOS to fresh nZVI, because Fe(OH)2 was the predominant phase on the nZVI surface independent of aging time. Sulfidation of nZVI reduced sorption of PFOS by 1 log unit owing to the FeS deposited, but the sorption affinity was restored after aging because of formation of Fe(OH)2. Oxidation of nZVI by water and dissolved oxygen also resulted in similar sorption of PFOS as fresh nZVI at environmentally relevant concentrations. The results suggest that injection of nZVI could reduce PFAA concentrations in groundwater despite changes to its surface chemistry with aging. DA - 2018/// PY - 2018/// DO - 10.1021/acs.est.8b00487 VL - 52 IS - 11 SP - 6300-6308 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85046541268&partnerID=MN8TOARS ER - TY - JOUR TI - Sorption and desorption of anionic, cationic and zwitterionic polyfluoroalkyl substances by soil organic matter and pyrogenic carbonaceous materials AU - Zhi, Y. AU - Liu, J. T2 - Chemical Engineering Journal AB - The fraction of pyrogenic carbonaceous materials (PCMs) left in aqueous film-forming foams (AFFFs) source zones may strongly affect the persistence of perfluoroalkyl and polyfluoroalkyl substances (PFASs). To examine the hypothesis and gain an additional perspective on the potential contributions of different organic phases present in soil, we measured sorption and desorption of five AFFF relevant PFASs, one cationic (perfluoroctaneamido ammonium iodide, PFOAAmS), two anionic (perfluorooctane sulfonate, PFOS; perfluorooctanoic carboxylate, PFOA), and two zwitterionic (perfluorooctane amido betaine, PFOAB; 6:2 fluorotelomer sulfonamido betaine, 6:2 FTAB), by three types of PCMs (biochar, soot, and oil-free soot) and soil organic matter (SOM, presented by Pahokee peat) by single-solute batch sorption experiments. It was found that sorption to PCMs is substantially stronger and nonlinear than SOM, especially for the cationic PFOAAmS. Strong sorption to PCMs discovered in this study suggests that such phenomenon can lead to high retardation of PFASs in the AFFF source zone and decreased mobility of PFASs in groundwater, especially for the precursor compounds to the legacy perfluoroalkyl acids. Fouling of PCMs by unburnt oil would hinder the surface activity of PCMs and consequently lower the sorption of PFAS, thereby facilitating PFAS mobility. Moreover, sorption hysteresis was observed in all the systems with sorption of 6:2 FTAB by biochar being the most significant. This study for the first time provided the evidence that PCMs are potentially a significant sink of PFASs in AFFF-impacted sites. DA - 2018/// PY - 2018/// DO - 10.1016/j.cej.2018.04.042 VL - 346 SP - 682-691 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85045706158&partnerID=MN8TOARS KW - PFOS KW - PFOA KW - Pyrogenic carbonaceous materials KW - Soil organic matter KW - Biochar KW - Soot ER - TY - CONF TI - Unintended Consequences of a Local Fats, Oils, and Grease Limits AU - Sadler, M. AU - Wischer, B. AU - Gordon, J. AU - Wilkerson, C. AU - Tabor, C. AU - Fredericks, D. AU - Ducoste, J. T2 - Virginia Water Environment Association (WEA) Industrial Waste & Pretreatment Conference C2 - 2018/3/5/ CY - Charlottesville, VA DA - 2018/3/5/ PY - 2018/3/5/ ER - TY - SOUND TI - A Spatial Variation Model Describing Generation, Accumulation, and Propagation of Heat in Municipal Solid AU - Hao, Z. AU - Ducoste, J. AU - Barlaz, M. DA - 2018/2/11/ PY - 2018/2/11/ ER - TY - CONF TI - Alternative Binder Materials and its Application in Concrete Sewer Structures for Possible Reduction in Fat, Oil and Grease (FOG) Related Sanitary Sewer Overflows (SSOs) AU - Kusum, S. AU - Pour-Ghaz, M. AU - Ducoste, J. T2 - North Carolina Section of the American Water Works Association (NC AWWA) Water Environment Association (WEA) Spring Symposium Conference C2 - 2018/// CY - Ashville, NC DA - 2018/// PY - 2018/3/25/ ER - TY - CONF TI - Evaluating alternative binder materials for Sewer Collection System Concrete Structures to reduce FOG related SSOs AU - Kusum, S. AU - Pour-Ghaz, M. AU - Ducoste, J. T2 - Water Environment Foundation (WEF) Collection System Specialty Conference C2 - 2018/4/8/ CY - Virginia Beach, VA DA - 2018/4/8/ PY - 2018/4/8/ ER - TY - CONF TI - Dynamic modeling of Dunaliella viridis growth and storage molecule production under different light and nitrogen conditions AU - Wang, Diyuan AU - Lai, Yichun AU - Karam, Amanda AU - de los Reyes, Francis AU - Ducoste, Joel T2 - North Carolina Microbiome Consortium Symposium C2 - 2018/// CY - Raleigh, NC DA - 2018/// PY - 2018/5/15/ ER - TY - SOUND TI - Building your Academic Brand AU - Ducoste, J.J. DA - 2018/3/23/ PY - 2018/3/23/ ER - TY - SOUND TI - Development of Photochemical Microsensors for Evaluating Light Distributions within Algal Photosynthetic Bioreactors AU - Ducoste, J.J. DA - 2018/4/13/ PY - 2018/4/13/ ER - TY - SOUND TI - Slip Sliding away: Minimizing FOG Deposit Adhesion to Sewer Surfaces AU - Ducoste, J.J. DA - 2018/8/20/ PY - 2018/8/20/ ER - TY - SOUND TI - Assessing Surface Characteristics to reduce the adhesion of Fats, Oils, and Grease Deposits AU - Ducoste, J.J. DA - 2018/10/16/ PY - 2018/10/16/ M3 - Keynote ER - TY - SOUND TI - Tips/information to successfully navigate graduate school Application/Decision and Fellowship Opportunities AU - Ducoste, J.J. DA - 2018/10/30/ PY - 2018/10/30/ PB - University of North ER - TY - SOUND TI - The Art of a graduate school Application: What’s in the mind of Faculty AU - Ducoste, J.J. DA - 2018/11/13/ PY - 2018/11/13/ ER - TY - SOUND TI - A life’s Journey in Being a Transformative Agent of Change AU - Ducoste, J.J. DA - 2018/11/19/ PY - 2018/11/19/ ER - TY - ER - TY - CONF TI - An algorithm to simulate segment speed trajectories of a metrorail segment for energy consumption estimation AU - Yuan, W. AU - Christopher Frey, H. C2 - 2018/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2018/// VL - 2018-June UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85056337873&partnerID=MN8TOARS ER - TY - CONF TI - Evaluation of Fiber-Reinforced Asphalt Concrete Mixtures Using a Viscoelastoplastic Continuum Damage Model AU - Saleh, N.F. AU - Kassem, H.A. AU - Zalghout, A. AU - Chehab, G. T2 - Transportation Research Board (TRB) 97th Annual Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/1/7/ ER - TY - CONF TI - Assessment of Fiber-Reinforced Asphalt Concrete Mixtures Using Advanced Material Characterization AU - Kassem, H.A. AU - Saleh, N.F. AU - Zalghout, A. AU - Chehab, G. T2 - Transportation Research Board (TRB) 97th Annual Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/1/7/ ER - TY - CONF TI - Constructability Study of Asphalt Pavements Incorporating Shallow Geothermal Energy AU - Zalghout, A. AU - Saleh, N.F. AU - Din, S.Sari Ad AU - Chehab, G. T2 - Second European and Mediterranean Structural Engineering and Construction Conference C2 - 2018/// CY - Beirut, Lebanon DA - 2018/// PY - 2018/7// ER - TY - JOUR TI - CONSTRUCTABILITY STUDY OF ASPHALT PAVEMENTS INCORPORATING SHALLOW GEOTHERMAL ENERGY AU - Zalghout, Ali AU - Saleh, Nooralhuda AU - Sari Ad Din, Samir AU - Chehab, Ghassan T2 - Proceedings of International Structural Engineering and Construction AB - The incorporation of geothermal energy in heating and electricity production has rapidly increased during the last three decades. This paper focuses on the use of shallow geothermal energy in asphalt pavement, herein called Ground Coupled Hydronic Asphalt Pavement (GCHAP) system. GCHAP consists of a series of pipes embedded within the asphalt layer coupled with another network of pipes embedded in the soil. A circulating fluid acts to exchange the heat energy between the soil and the asphalt layer. The system can be used for cooling the pavement, which results in decreasing permanent deformation in the summer. This paper presents a study on the constructability and performance of such systems on a large-scale section. Numerical analyses and a pilot study were conducted to select the system design components. A 9.6 x 4 meter GCHAP section was constructed on a municipal road in addition to another control section. The secondary network of pipes was placed three meters below the ground. Sensors were embedded within the GCHAP system to record and compare the temperature of the pavement to that of the control section. The results showed that GCHAP section can decrease the pavement temperature leading to an increase in resistance to permanent deformation. Moreover, the constructability study showed the importance of performing a pilot study before constructing the system to ensure the resilience of the pipes. DA - 2018/7// PY - 2018/7// DO - 10.14455/isec.res.2018.14 VL - 5 IS - 1 LA - en OP - SN - 2644-108X UR - http://dx.doi.org/10.14455/isec.res.2018.14 DB - Crossref ER - TY - CHAP TI - Thermal analysis of hydronic asphalt pavement systems AU - Din, S.A. Sari Ad AU - Saleh, N.F. AU - Zalghout, A.A. AU - Chehab, G.R. T2 - Advances in Materials and Pavement Performance Prediction AB - The emergence of Hydronic Asphalt Pavements (HAPs) presents an alternative pavement system that is both more durable and more sustainable. HAP consists of a series of pipes embedded within the asphalt pavement and through which a fluid circulates. The purpose of such a system can be any of the following: snow-melting and deicing, cooling the pavement, and/or energy-extraction. In this paper, a transient 3D heat transfer model is developed in a MATLAB environment to simulate the thermal behavior of HAPs as geometrical and thermo-physical properties of the system are varied. It was found that the surface temperature of the pavement is sensitive mostly to the thermal conductivity of the pavement, followed by pipe spacing, depth, diameter, and lastly flow rate. It was also established that investing in asphalt of higher conductivity can be more economical than using pipes of high conductivity such as copper. PY - 2018/7/16/ DO - 10.1201/9780429457791-130 SP - 539-542 OP - PB - CRC Press SN - 9780429457791 UR - http://dx.doi.org/10.1201/9780429457791-130 DB - Crossref ER - TY - CONF TI - Thermal analysis of hydronic asphalt pavement systems AU - Sari Ad Din, S.A. AU - Saleh, N.F. AU - Zalghout, A.A. AU - Chehab, G.R. C2 - 2018/// C3 - Advances in Materials and Pavement Performance Prediction - Proceedings of the International AM3P Conference, 2018 DA - 2018/// SP - 539-542 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85061285879&partnerID=MN8TOARS ER - TY - CONF TI - Assessment of fiber reinforced hma and wma mixes using viscoelastic continuum damage model AU - Kassem, H.A. AU - Chehab, G.R. AU - Saleh, N.F. AU - Zalghout, A. AB - In the road industry, the current challenge is to produce at lower manufacture temperatures asphalt mixtures incorporating Reclaimed Asphalts (RA). However, the incorporation of cold RA could lead to a non-remobilization of the RA aged binder by the virgin one. A double coating appears, what leads to a binders non-mixture and poorer mechanical properties of asphalt mixtures. The objectives are to develop methods to understand remobilization mechanisms and precisely how the virgin binder comes into contact and diffuses into the RA binder. The temperature influence was investigated. Results show that contact angle measurements and micro X-ray fluorescence have been successfully adapted to the 'bitumen/bitumen' interface and interphase study. The RA temperature governs the remobilization initiation phase and influences the blending zone dimension. Therefore, RA should be heated before their incorporation in order to avoid a non-remobilization and guarantee favorable conditions to obtain homogeneous recycled asphalt mixtures with high mechanical performances. C2 - 2018/// C3 - Bearing Capacity of Roads, Railways and Airfields - Proceedings of the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017 DA - 2018/// DO - 10.1201/9781315100333-174 SP - 1197-1204 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85053277190&partnerID=MN8TOARS ER - TY - JOUR TI - Advanced characterization of asphalt concrete mixtures reinforced with synthetic fibers AU - Kassem, H.A. AU - Saleh, N.F. AU - Zalghout, A.A. AU - Chehab, G.R. T2 - Journal of Materials in Civil Engineering AB - This study evaluates the behavior of fiber-reinforced asphalt mixtures using advanced material characterization and performance prediction models. The polymeric nature of the proprietary blend of polyolefin and aramid fibers used warrants examining the contribution of the fibers not only to the physical network of the mixture but also to the extent of modification of the asphalt binder upon mixing. The effect of adding these synthetic fibers on the performance of asphalt concrete mixtures is assessed in the state of compression to investigate the resistance to rutting by (1) using a viscoelastoplastic continuum damage (VEPCD) model to provide an accurate and realistic assessment, and (2) by conducting a mechanistic-empirical (ME) analysis using Pavement ME software because it is the state of practice in pavement design and analysis. Upon addition of fibers, the developed VEPCD models indicate an overall improvement in the performance in terms of predicted strain in response to a given stress profile. Fibers are found to impose a faster recovery of viscoelastic strains during rest periods and lower strains during loading when added to a warm mix asphalt (WMA) mix containing unmodified binder. Fibers are also found to reduce the viscoplastic strains of both hot mix asphalt (HMA) and WMA mixtures at 5°C and of HMA mixture at 35°C. The performance improvement due to fibers is enhanced when using fibers of shorter length, using fibers in mixtures with wax-based additives, or in mixtures with coarser gradations. DA - 2018/// PY - 2018/// DO - 10.1061/(ASCE)MT.1943-5533.0002521 VL - 30 IS - 11 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85053266241&partnerID=MN8TOARS ER - TY - JOUR TI - Triaxial stress sweep test protocol considerations for permanent deformation characterisation of asphalt mixtures AU - Bastos, Juceline Batista dos S. AU - Torquato e Silva, Samuel de A. AU - Soares, Jorge B. AU - Nascimento, Luís Alberto H. AU - Kim, Y. Richard T2 - Road Materials and Pavement Design AB - Rutting is one of the most usual distresses in Brazilian asphaltic pavements and prediction of such distress is a major challenge. State of the art methodologies need consistency between laboratory test and field conditions. This paper investigates a potential modification of the triaxial stress sweep (TSS) test, according to deviator and confining stresses typically found in Brazilian roadways which have thinner surface courses than those for which the original protocol was developed. Different structures were simulated with typical material properties and layer thicknesses found in Brazil. A more realistic confining stress was adopted, and a deviator stress was calculated for each load level of the test protocol. A modified TSS test and the uniaxial repeated load test were performed in three asphalt mixes. One of them did not reach the minimum number of cycles, preventing rutting prediction, and suggesting a fragility of this particular mix with respect to the investigated distress. Such a result was co... DA - 2018/// PY - 2018/// DO - 10.1080/14680629.2016.1261729 VL - 19 IS - 2 SP - 431–444 SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2016.1261729 KW - asphalt mixtures KW - permanent deformation KW - triaxial stress sweep ER - TY - SOUND TI - Laboratory testing for Heat Generation Potential and Applications to Field Conditions AU - Barlaz, M.A. AU - Jafari, N. DA - 2018/11/7/ PY - 2018/11/7/ ER - TY - SOUND TI - Biological and Chemical Reactions Contributing to Heat Generation in Landfills: Current Research and Model Simulations AU - Barlaz, M.A. AU - Benson, C.H. DA - 2018/// PY - 2018/// PB - Research and Edcn. Fndn ER - TY - CONF TI - So you want to publish a peer-reviewed journal article on LCA: What are the expectations and what are reviewers looking for? AU - Barlaz, M.A. AU - Arena, U. AU - Damgaard, A. T2 - 2nd Conference on Life Cycle Assessment of Waste C2 - 2018/// CY - Technical University of Denmark DA - 2018/// PY - 2018/6/18/ ER - TY - RPRT TI - Development of Methods to Measure the Hydrogen Sulfide Production Potential of Sulfur-Containing Wastes AU - Sun, M. AU - Sun, W. AU - Barlaz, M.A. A3 - Environmental Research and Education Foundation DA - 2018/// PY - 2018/// PB - Environmental Research and Education Foundation ER - TY - CONF TI - Design of Waste Transfer Station Concrete Overlays Against Premature Deterioration AU - Park, S. AU - Castellano, L. AU - Pour-Ghaz, M. AU - Barlaz, M.A. T2 - SC Solid Waste Association of North America Annual Meeting C2 - 2018/// CY - Charleston, SC DA - 2018/// PY - 2018/11/5/ ER - TY - CONF TI - How Do We Address Data Quality in LCA of Waste Technologies AU - Damgaard, A. AU - Henriksen, T. AU - Levis, J.W. AU - Barlaz, M.A. T2 - 2nd Conference on Life Cycle Assessment of Waste C2 - 2018/// CY - Technical University of Denmark DA - 2018/// PY - 2018/6/18/ ER - TY - CONF TI - Multistage Life-Cycle Optimization for Developing and Evaluating Current and Future Solid Waste Systems AU - Levis, J.W. AU - Barlaz, M.A. T2 - 2nd Conference on Life Cycle Assessment of Waste C2 - 2018/// CY - Technical University of Denmark DA - 2018/// PY - 2018/6/18/ ER - TY - CONF TI - Life-Cycle Model Development and Transparency: Challenges and Choices AU - Barlaz, M.A. AU - Levis, J.W. T2 - 2nd Conference on Life Cycle Assessment of Waste C2 - 2018/// CY - Technical University of Denmark DA - 2018/// PY - 2018/6/18/ ER - TY - CONF TI - The Effect of Organic Acids on the Abrasion Resistance of Cementitious Materials AU - Park, S. AU - Pour-Ghaz, M. AU - Castellano, L. AU - Barlaz, M. T2 - 9th Advances in Cement-Based Materials C2 - 2018/// CY - State College, PA DA - 2018/// PY - 2018/6/11/ ER - TY - CONF TI - Life Cycle Modeling for Future Solid Waste Management Planning AU - Levis, J.W. AU - Jaunich, M.K. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2018/// CY - Indian Wells, CA DA - 2018/// PY - 2018/2/11/ ER - TY - CONF TI - Heat Generation and Accumulation in Municipal Solid Waste Landfills AU - Hao, Z. AU - Ducoste, J. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2018/// CY - Indian Wells, CA DA - 2018/// PY - 2018/2/11/ ER - TY - CONF TI - Microbial Population Development during the Anaerobic decomposition of Food Waste AU - Lee., E. AU - de los Reyes, F.L. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2018/// CY - Indian Wells, CA DA - 2018/// PY - 2018/2/11/ ER - TY - JOUR TI - Fatigue Properties of Nano-Reinforced Bituminous Mixtures: A Viscoelastic Continuum Damage Approach AU - Miglietta, F. AU - Underwood, B.S. AU - Tsantilis, L. AU - Baglieri, O. AU - Kaloush, K.E. AU - Santagata, E. T2 - International Journal of Pavement Research and Technology AB - Abstract The experimental investigation described in this paper focused on the effects of nanoclays on the fatigue behaviour of bituminous mixtures. Damage characteristics of a bituminous mixture produced by making use of a nano-reinforced binder were compared to those of a reference mixture obtained by employing the same neat bitumen used as a base in the preparation of the nanoclay–bitumen blend. Dynamic modulus tests and direct tension cyclic fatigue tests were carried out to determine the linear viscoelastic properties and the damage evolution characteristics of materials. Corresponding results were modelled by means of a viscoelastic continuum damage approach and by making use of a more empirical evaluation based on the classical Wohler representation. It was found that the use of nanoclays produced a reinforcement of bituminous mixtures, the benefits of which were observed both in the progression of damage and in the occurrence of ultimate failure conditions. DA - 2018/5// PY - 2018/5// DO - 10.1016/j.ijprt.2018.04.004 VL - 11 IS - 7 SP - 766–773 SN - 1996-6814 ER - TY - SOUND TI - Synthesis on National Water Use: Spatial Patterns and Socio-economic Controls, State of America’s Water: Present and Future AU - Arumugam, S. DA - 2018/1/10/ PY - 2018/1/10/ ER - TY - SOUND TI - Synthesis on National Water Use: Spatial Patterns and Socio-economic Controls, State of America’s Water: Present and Future AU - Arumugam, S. DA - 2018/4/6/ PY - 2018/4/6/ ER - TY - SOUND TI - Synthesis of public water supply use in the United States and China: Spatio-temporal patterns and socio-economic controls DA - 2018/5/22/ PY - 2018/5/22/ ER - TY - CONF TI - Climate-Water-Energy Nexus: Uncertainty Reduction in Climate Forecasts using Multimodel Combination and their relevance to Water and Energy Management T2 - Indian Institute of Science C2 - 2018/6/19/ DA - 2018/6/19/ PY - 2018/6/19/ ER - TY - CONF TI - Climate-Water-Energy Nexus: Opportunities and Challenge AU - Arumugam, S. T2 - CoPE workshop C2 - 2018/10// CY - Atlanta, Georgia DA - 2018/10// PY - 2018/10// ER - TY - CONF TI - Climate-Water-Energy Nexus: Uncertainty Reduction in Climate Forecasts Using Multimodel Combination and their Relevance to Water and Energy Management AU - Arumugam, S. T2 - World Council for Energy and Climate C2 - 2018/// CY - Shanghai DA - 2018/// PY - 2018/// ER - TY - CONF TI - Effects of dam purpose and degree of regulation on flow regime alteration over the continental United States AU - Chalise, D.R. AU - Arumugam, S. AU - Ruhi, A. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - Water: Fourth U.S. National Climate Assessment (NCA4) Volume 2, Chapter 3 AU - Johnson, T. AU - Lall, U. AU - AghaKouchak, A. AU - Arumugam, S. AU - Brown, C. AU - McCabe, G.J., Jr. AU - Pulwarty, R.S. AU - Colohan, P. AU - Lewis, K. AU - Lustig, A. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - Application of Sub-seasonal to Seasonal (S2S) precipitation forecast in multipurpose multi-reservoir system for water and energy management AU - Mukhopadhyay, S. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - Understanding the cumulative effects of dams on regional streamflow dynamics AU - Ruhi, A. AU - Worland, S. AU - Mukhopadhyay, S. AU - Devineni, N. AU - Chalise, D. AU - Salinas, J.L. AU - Mazrooei, A. AU - Abeshu, G. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - The Role of Spatial Variability of Climate Variables on the Long-Term Water Balance Using a Semi-distributed (SWAT) Mechanistic Model AU - Libera, D. AU - Wang, D. AU - Yao, l. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - A Conceptual Approach using the Limits Concept for Extending Budyko's Framework for Natural Watersheds and Human-Altered Landscapes AU - Arumugam, S. AU - Wang, D. AU - Devineni, N. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - Global assessment of evapotranspiration impacted by anthropogenic land cover changes AU - Mazrooei, A. AU - Reitz, M. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - CONF TI - Evaluating the Controls of the Long-Term Water Balance through a Conceptual Hydrological Model Representing Saturation Excess and Infiltration Excess Runoff Generations AU - Yao, L. AU - Wang, D. AU - Libera, D. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2018/// CY - Washington, DC DA - 2018/// PY - 2018/12/10/ ER - TY - RPRT TI - WSC - Category 3: Collaborative Research: Water Sustainability under Near-term Climate Change: A Cross-Regional Analysis Incorporating Socio-Ecological Feedbacks and Adaptations AU - Sankarasubramanian, A. AU - Mahinthakumar, G. AU - Berglund, E. DA - 2018/// PY - 2018/// M3 - National Science Foundation ER - TY - RPRT TI - Water AU - Lall, Upmanu AU - Johnson, Thomas AU - Colohan, Peter AU - Aghakouchak, Amir AU - Arumugam, Sankar AU - Brown, Casey AU - Mccabe, Gregory J. AU - Pulwarty, Roger S. A3 - U.S. Global Change Research Program AB - This report is an authoritative assessment of the science of climate change, with a focus on the United States. It represents the second of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990. DA - 2018/// PY - 2018/// DO - 10.7930/NCA4.2018.CH3 PB - U.S. Global Change Research Program UR - http://dx.doi.org/10.7930/NCA4.2018.CH3 ER - TY - JOUR TI - Identifying tourists and analyzing spatial patterns of their destinations from location-based social media data AU - Hasnat, Md Mehedi AU - Hasan, Samiul T2 - Transportation Research Part C: Emerging Technologies DA - 2018/// PY - 2018/// VL - 96 SP - 38-54 ER - TY - CONF TI - Development of updated MOVES Lite: A simplified version of MOVES AU - Khan, T. AU - Christopher Frey, H. AU - Wei, T. C2 - 2018/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2018/// VL - 2018-June UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85056328664&partnerID=MN8TOARS ER - TY - CONF TI - Development and validation of transit bus energy use rate models AU - Wei, T. AU - Christopher Frey, H. AU - Khan, T. C2 - 2018/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2018/// VL - 2018-June UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85056318902&partnerID=MN8TOARS ER - TY - RPRT TI - Evaluation of cVOC Removal Efficiencies by Various Technologies AU - Cotton, C. AU - Collins, J. AU - Knappe, D.R.U. AU - Linden, K. AU - Brown, J. AU - Upadhyaya, G. AU - Ponturo, P. A3 - Water Research Foundation DA - 2018/// PY - 2018/// M1 - 4492 M3 - Executive Summary PB - Water Research Foundation SN - 4492 ER - TY - JOUR TI - Decision Support Algorithm for Evaluating Carbon Dioxide Emissions from Electricity Generation in the United States AU - Ryan, N.A. AU - Johnson, J.X. AU - Keoleian, G.A. AU - Lewis, G. T2 - Journal of Industrial Ecology AB - Summary This article presents an algorithm to aid practitioners in determining the most appropriate method to estimate carbon dioxide emissions from an electricity load. Applications include sustainability assessments of products, processes, energy efficiency improvements, changes in generation infrastructure, and changes in electricity demand. Currently, there is no consensus on appropriate methods for calculating greenhouse gas emissions resulting from specific electricity loads. Previous research revealed significant differences in emissions when different methods were used, a situation that could result in divergent sustainability or policy recommendations. In this article, we illustrate the distribution of emissions estimates based on method characteristics such as region size, temporal resolution, average or marginal approaches, and time scales. Informed by these findings, a decision support algorithm is presented that uses a load's key features and an analyst's research question to provide recommendations on appropriate method types. We defined four different cases to demonstrate the utility of the algorithm and to illustrate the variability of methods used in previous studies. Prior research often employed simplifying assumptions, which, in some cases, can result in electricity being allocated to the incorrect generating resources and improper calculation of emissions. This algorithm could reduce inappropriate allocation, variability in assumptions, and increase appropriateness of electricity emissions estimates. DA - 2018/10// PY - 2018/10// DO - 10.1111/jiec.12708 VL - 22 IS - 6 SP - 1318-1330 KW - electricity generation KW - electric utility KW - emissions factor KW - greenhouse gas (GHG) emissions KW - industrial ecology marginal emissions ER - TY - CONF TI - Toward improving damping characterization for site response analysis AU - Cabas, A. AU - Rodriguez-Marek, A. C2 - 2018/// C3 - Proceedings from the ASCE 5th Geotechnical Earthquake Engineering and Soil Dynamics Conference DA - 2018/// PB - ASCE Geotechnical Special Publication ER - TY - CONF TI - Assessment of the Influence of the Elastic Halfspace on Site Response Estimations AU - Chowdhury, I.N. AU - Cabas, A. T2 - 11th National Conference on Earthquake Engineering C2 - 2018/// CY - Los Angeles, CA DA - 2018/// PY - 2018/6/25/ ER - TY - CONF TI - Investigation of the Dependence of Kappa Values on the Onset of Soil Nonlinearity as Captured by Shear Strain Index (PGV/Vs30) AU - Ji, C. AU - Cabas, A. T2 - Seismology of the Americas (joint conference of the Latin American and Caribbean Seismological Commission (LACSC) and the Seismological Society of America (SSA) C2 - 2018/5/14/ C3 - Seismology of the Americas (joint conference of the Latin American and Caribbean Seismological Commission (LACSC) and the Seismological Society of America (SSA CY - Florida DA - 2018/5/14/ PY - 2018/5/14/ ER - TY - CONF TI - Effects of General Contractor’s Loading Strategies on Project and Trades’ Performance AU - Javanmardi, Ashtad AU - Hsiang, Simon M. AU - Liu, Min T2 - Construction Research Congress 2018 AB - General contractor’s (GC) loading strategies, defined as the amount of work GC assigns to trades in a given time, directly impact project and trades’ performance. Previous researchers have discussed that it is beneficial not to load 100% of trades production capacity and account for variability in the flow of work passing from one trade to another. However, there has been limited research identifying to what extent underloading is beneficial for both trades and the project. By modifying the Parade Game model and considering different levels of workflow variability, this paper quantifies the effects of GC’s loading strategies on project cycle time and trades’ utilization. This study simulates a single-line production system in which GC controls the rate of work assigned to the production system. Results show that: (1) although underloading will result in shorter cycle times, 40% underloading could lower trades’ average utilization up to 34%; and (2) in a variable production system with a coefficient of variation (CV) of 0.71, variability should be reduced 1.625 times more to achieve a short cycle time of 6 weeks but 14% more trades’ average utilization, considering 70% trades’ average utilization as a benchmark. The findings of this paper will be useful to project managers by enabling them to develop production strategies that lead to better project cycle time and trades’ utilization. C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481271.044 PB - American Society of Civil Engineers SN - 9780784481271 UR - http://dx.doi.org/10.1061/9780784481271.044 DB - Crossref ER - TY - CONF TI - Improved Stakeholder Communication and Visualizations: Real-Time Interaction and Cost Estimation within Immersive Virtual Environments AU - Balali, Vahid AU - Noghabaei, Mojtaba AU - Heydarian, Arsalan AU - Han, Kevin T2 - Construction Research Congress 2018 AB - One of the main desired qualities of an efficient project management in the construction industry is the ability to visualize a construction project in 2D drawings and execute them accurately and efficiently on-site. However, there are several types of delays that significantly influence project durations, often resulting from misunderstanding and miscommunications among parties (owners, contractors, and other stakeholders). One of the more common delays is change orders that are usually attributed as one of the major reasons behind delays in construction. Making changes after a building enters the construction phase can be very expensive, conflicting, and time-consuming. Such delays may arise due to the lack of communication and coordination among the owner and the contractors regarding the change orders. In most instances, it is highly conflicting to form a mutual agreement when there is a predicted price difference to accept a change order. To minimize the impact of change orders on the design and total cost, an approach that allows communication and interaction with 3D models through advanced visualization tools (i.e., virtual and augmented reality environments) can be effective. To further identify the influence of immersive virtual environments (IVEs) on project management, a systematic approach is proposed through which stakeholders can: (1) visualize and interact with 3D models in one-to-one scaled realistic virtual environments (fully immersive); and (2) visualize the dollar amount changes as the results of change orders. The results of the presented case study show that clients can exercise the ability to make changes virtually well before actual construction begins. C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481264.051 PB - American Society of Civil Engineers SN - 9780784481264 UR - http://dx.doi.org/10.1061/9780784481264.051 DB - Crossref ER - TY - CONF TI - The Distracted Worker: Effect on Hazard Recognition and Safety Performance AU - Namian, Mostafa AU - Albert, Alex AU - Feng, Jing T2 - Construction Research Congress 2018 AB - Hazard recognition is an essential element for successful accident and injury prevention. However, studies have revealed that construction workers fail to identify a large proportion of hazards in their workplaces. Therefore, understanding factors that adversely affect hazard recognition performance is a fundamental step towards improving safety performance. Given the unique, complex, and dynamic nature of construction operations, past research has provided anecdotal evidence suggesting that distraction may be correlated to undesirable safety outcomes such as injuries. For example, Hinze’s distraction theory suggests that workers are more likely to be involved in an accident while they are distracted. However, these theoretical propositions have not been empirically tested. To address this knowledge gap, the objective of this research was to test the hypothesis that distracted workers will identify fewer hazards than undistracted workers. To test the hypothesis, an experiment was conducted with 70 construction workers where the participants were randomly assigned to a distracted or an undistracted group. Sixteen pre-selected case images, representing real construction operations, were used to evaluate the hazard recognition performance of the workers. For the distracted group, distraction was induced using visual stimuli presented as unrelated video clips during the hazard recognition activity. The data analysis results showed that the distracted workers recognized a smaller proportion of hazards than the undistracted workers (p-value = 0.003). The research findings indicate that reducing workplace distractions can be a useful intervention to improve the safety performance of construction workers such as hazard recognition levels. C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481288.036 PB - American Society of Civil Engineers SN - 9780784481288 UR - http://dx.doi.org/10.1061/9780784481288.036 DB - Crossref ER - TY - CONF TI - Scaling Personalized Safety Training Using Automated Feedback Generation AU - Jeelani, Idris AU - Han, Kevin AU - Albert, Alex T2 - Construction Research Congress 2018 AB - Hazard identification is one of the primary steps in effective safety management. However, research has shown that a large proportion of construction hazards remain unrecognized in workplaces, which expose workers to unanticipated risks. While researchers and practitioners have developed several training programs to improve hazard recognition levels, much of this effort has proceeded with limited understanding of factors that impede hazard recognition at the worker level. Recent studies have suggested a strong correlation between viewing patterns of workers and their hazard recognition performance. Hence, it is important to study and analyze the viewing patterns of workers to gain a better understanding of their hazard recognition performance. From the training point of view, scan paths and attention maps can be used, very effectively, to provide personalized and focused feedback to workers to communicate search process deficiency, trigger self-reflection processes, and improve subsequent hazard search performance. However, providing the personalized visual attention feedback requires the recording of scan paths of individual workers and examining the data manually, which is very time-consuming and susceptible to human errors. Consequently, the manual process can result in inaccurate assessments and inefficient feedback. In an attempt to automate and scale up the generation of personalized feedback, this paper proposes a computer vision-based method that tracks workers in a construction site and automatically locates their fixation points (collected by a wearable eye tracker). Using the localized positions of workers and the fixation data from the wearable eye tracker, each worker’s viewing behavior (i.e., attention distribution, fixation points, etc.) is monitored analyzed to generate personalized feedback for training purposes. The presented case study validates the proposed method and the results show the potential of automating and scaling up personalized feedback generation. C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481288.020 PB - American Society of Civil Engineers SN - 9780784481288 UR - http://dx.doi.org/10.1061/9780784481288.020 DB - Crossref ER - TY - CONF TI - Using Virtual Prototyping to Select Compatible Fall Protection Supplementary Devices for Bridge Maintenance Work AU - Zuluaga, Carlos M. AU - Albert, Alex T2 - Construction Research Congress 2018 AB - Existing bridge guardrails generally serve as an effective barrier to protect workers from falls to lower levels during maintenance work on bridge-decks. However, a large number of bridge guardrails do not fulfill the regulatory height requirement of 42 ± 3 in. for sufficient fall protection. One underutilized but effective solution is to install fall protection supplementary devices (FPSDs) on existing bridge guardrails to increase the overall barrier height while work is being performed. Yet, workers experience significant challenges when attempting to use these devices. First, not all FPSDs available in the market are compatible with every bridge guardrail. Second, workers currently use an inefficient trial-and-error based procedure to test the compatibility between guardrails and FPSD systems in the field. Third, when compatible FPSD systems are not readily available, workers often use less effective fall protection controls that expose workers to higher levels of safety risk. The objective of this study was to find suitable FPSDs compatible with bridge guardrails in North Carolina. To overcome the issues associated with the manual procedure, we used virtual prototyping methods to (1) capture the design characteristics of bridge guardrails and FPSDs, and (2) complete compatibility testing by attempting to attach each FPSD onto each guardrail in a virtual environment. To offer corroborative evidence of the proposed methodology, a case study is presented evaluating the compatibility of commercially available FPSDs with prevailing guardrails in the state of North Carolina. The implementation of this virtual compatibility testing method will allow practitioners to efficiently and cost-effectively select compatible FPSDs to improve safety, efficiency, and productivity. It is anticipated that the advantages of this method over manual techniques will encourage more safety practitioners to adopt FPSD systems to protect their workforce. C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481288.010 PB - American Society of Civil Engineers SN - 9780784481288 UR - http://dx.doi.org/10.1061/9780784481288.010 DB - Crossref ER - TY - CONF TI - Liquefaction Triggering, Consequences, and Mitigation AU - Zamani, A. AU - Feng, K. AU - Montoya, B. M. T2 - Geotechnical Earthquake Engineering and Soil Dynamics V AB - Microbial induced calcium carbonate precipitation (MICP) has been shown to be an effective method to improve soil strength and stiffness, and one of the most promising applications of MICP is for liquefaction mitigation. In this paper, three silica soils with varying grain sizes were treated by MICP to a moderate level of cementation and their resistance to liquefaction is improved significantly compared to uncemented loose soil. The degree of MICP improvement appears to be influenced by the grain size and shape of the loose untreated soil. The level of excess pore water and cyclic resistance of the untreated and MICP treated soils is presented. The different response to cyclic loading after MICP treatment is compared with respect to different grain size and shape. The results show that reduction in grain size and increase in angularity result in a higher resistance to liquefaction after MICP treatment. C2 - 2018/6/7/ C3 - Geotechnical Earthquake Engineering and Soil Dynamics V DA - 2018/6/7/ DO - 10.1061/9780784481455.029 PB - American Society of Civil Engineers SN - 9780784481455 UR - http://dx.doi.org/10.1061/9780784481455.029 DB - Crossref ER - TY - JOUR TI - A review of approaches to uncertainty assessment in energy system optimization models AU - Yue, Xiufeng AU - Pye, Steve AU - DeCarolis, Joseph AU - Li, Francis G.N. AU - Rogan, Fionn AU - Gallachóir, Brian Ó. T2 - Energy Strategy Reviews AB - Energy system optimization models (ESOMs) have been used extensively in providing insights to decision makers on issues related to climate and energy policy. However, there is a concern that the uncertainties inherent in the model structures and input parameters are at best underplayed and at worst ignored. Compared to other types of energy models, ESOMs tend to use scenarios to handle uncertainties or treat them as a marginal issue. Without adequately addressing uncertainties, the model insights may be limited, lack robustness, and may mislead decision makers. This paper provides an in-depth review of systematic techniques that address uncertainties for ESOMs. We have identified four prevailing uncertainty approaches that have been applied to ESOM type models: Monte Carlo analysis, stochastic programming, robust optimization, and modelling to generate alternatives. For each method, we review the principles, techniques, and how they are utilized to improve the robustness of the model results to provide extra policy insights. In the end, we provide a critical appraisal on the use of these methods. DA - 2018/8// PY - 2018/8// DO - 10.1016/J.ESR.2018.06.003 VL - 21 SP - 204-217 J2 - Energy Strategy Reviews LA - en OP - SN - 2211-467X UR - http://dx.doi.org/10.1016/J.ESR.2018.06.003 DB - Crossref KW - Energy system modelling KW - Uncertainty KW - Monte Carlo analysis KW - Stochastic programming KW - Robust optimization KW - Modelling to generate alternatives ER - TY - JOUR TI - Effects of Basalt Fibres on Mechanical Properties of Concrete AU - El-Gelani, A. M. AU - High, C.M. AU - Rizkalla, S. H. AU - Abdalla, E. A. T2 - MATEC Web of Conferences AB - This paper presents the results of an experimental program carried out to investigate the effects of Basalt Fibre Reinforced Polymers (BFRP) on some fundamental mechanical properties of concrete. Basalt fibres are formed by heating crushed basalt rocks and funnelling the molten basalt through a spinneret to form basalt filaments. This type of fibres have not been widely used till recently. Two commercially available chopped basalt fibres products with different aspect ratios were investigated, which are dry basalt (GeoTech Fibre) and basalt pre-soaked in an epoxy resin (GeoTech Matrix) .The experimental work included compression tests on 96 cylinders made of multiple batches of concrete with varying amounts of basalt fibre additives of the two mentioned types, along with control batches containing no fibres. Furthermore, flexural tests on 24 prisms were carries out to measure the modulus of rupture, in addition to 30 prisms for average residual strength test. Results of the research indicated that use of basalt fibres has insignificant effects on compressive strength of plain concrete, where the increase in strength did not exceed about 5%. On the other hand, results suggest that the use of basalt fibres may increase the compressive strength of concrete containing fly as up top 40%. The rupture strength was increased also by 8% to 28% depending on mix and fibre types and contents. Finally, there was no clear correlation between the average residual strength and ratios of basalt fibres mixed with the different concrete batches. DA - 2018/// PY - 2018/// DO - 10.1051/MATECCONF/201814901028 VL - 149 SP - 01028 J2 - MATEC Web Conf. OP - SN - 2261-236X UR - http://dx.doi.org/10.1051/MATECCONF/201814901028 DB - Crossref ER - TY - JOUR TI - Effects of Basalt Fibres on Mechanical Properties of Concrete AU - El-Gelani, A. M. AU - High, C.M. AU - Rizkalla, S. H. AU - Abdalla, E. A. T2 - MATEC Web of Conferences AB - This paper presents the results of an experimental program carried out to investigate the effects of Basalt Fibre Reinforced Polymers (BFRP) on some fundamental mechanical properties of concrete. Basalt fibres are formed by heating crushed basalt rocks and funnelling the molten basalt through a spinneret to form basalt filaments. This type of fibres have not been widely used till recently. Two commercially available chopped basalt fibres products with different aspect ratios were investigated, which are dry basalt (GeoTech Fibre) and basalt pre-soaked in an epoxy resin (GeoTech Matrix) .The experimental work included compression tests on 96 cylinders made of multiple batches of concrete with varying amounts of basalt fibre additives of the two mentioned types, along with control batches containing no fibres. Furthermore, flexural tests on 24 prisms were carries out to measure the modulus of rupture, in addition to 30 prisms for average residual strength test. Results of the research indicated that use of basalt fibres has insignificant effects on compressive strength of plain concrete, where the increase in strength did not exceed about 5%. On the other hand, results suggest that the use of basalt fibres may increase the compressive strength of concrete containing fly as up top 40%. The rupture strength was increased also by 8% to 28% depending on mix and fibre types and contents. Finally, there was no clear correlation between the average residual strength and ratios of basalt fibres mixed with the different concrete batches. DA - 2018/// PY - 2018/// DO - 10.1051/MATECCONF/201714901028 VL - 149 SP - 01028 J2 - MATEC Web Conf. OP - SN - 2261-236X UR - http://dx.doi.org/10.1051/matecconf/201814901028 DB - Crossref ER - TY - CONF TI - Seismic AU - Keil, Brent D. AU - Gobler, Fritz AU - Mielke, Richard D. AU - Lucier, Gregory AU - Sarvanis, Gregory C. AU - Karamanos, Spyros A. T2 - Pipelines 2018 AB - Welded lap joints are commonly used in large-diameter steel pipelines for water transmission. Their structural performance constitutes a key issue for safeguarding pipeline structural integrity with no loss of pressure containment, required even after a severe seismic event. Full-scale experiments are presented herein, and are part of an extensive project sponsored and coordinated by Northwest Pipe Co. on the structural performance of welded lap joints under severe ground-induced (seismic) actions. In the companion paper “Numerical Simulation of Steel Lap Welded Pipe Joint Behavior in Seismic Conditions” numerical simulation of the experiments are presented. The paper describes a series of large-scale experiments on welded lap joints in 25.75 in outside diameter steel pipes, with wall thickness of 0.135 in (3 specimens) or 0.250 in (3 specimens). The specimens were internally pressurized to 40% of yield pressure, and then subjected to four-point bending. Measurements of the bending load, characteristic displacements, and local strains at the joint area are reported. In all tests, the welded lap joints tested were capable of sustaining remarkable bending deformation, without any loss of pressure containment. This behavior supports the argument that welded lap joints, if appropriately constructed, can be used in seismic areas where severe and permanent ground-induced actions in the pipeline may occur. C2 - 2018/7/11/ C3 - Pipelines 2018 DA - 2018/7/11/ DO - 10.1061/9780784481646.045 PB - American Society of Civil Engineers SN - 9780784481646 UR - http://dx.doi.org/10.1061/9780784481646.045 DB - Crossref ER - TY - JOUR TI - Improved Synchronous and Alternate Vacuum Preloading Method for Newly Dredged Fills: Laboratory Model Study AU - Liu, Jingjin AU - Lei, Huayang AU - Zheng, Gang AU - Feng, Shuangxi AU - Rahman, M. S. T2 - International Journal of Geomechanics AB - Cost effectiveness is a major factor in most vacuum preloading projects, considering the significantly reduced time allotted to achieve a relatively high degree of consolidation. However, the shallow base and deep layer of newly dredged fills are always treated separately because the traditional vacuum preloading method can barely make sufficient improvement in the one-time treatment in these weak and complex grounds. Therefore, an improved vacuum preloading method was developed to consolidate newly dredged fills in the Lin Gang Industrial Zone of Tianjin City, China. This improved method consists of three main systems: loading devices, a vacuum preloading system, and a moisture separator technique. By using two loading devices, two lengths of the prefabricated vertical drains (PVDs), and a novel moisture separator, the shallow base and deep layer of the newly dredged fills can be simultaneously processed. The results of water discharge and pore water pressure were measured using three parallel laboratory model tests. The moisture content test and the mercury intrusion porosimetry (MIP) test were conducted along with the vane shear strength test. The testing data shows that the improved vacuum preloading method can substantially improve the bearing capacity of an ultrasoft ground. The multiple vacuum preloading method and the improved synchronous and alternate vacuum preloading method increased the water discharge amount by 8.4% and 27.9%, respectively, over the traditional method. The final dissipation of pore water pressure by the traditional method was one-fifth of that of the improved method because the motion directions of soil particles were changed in the improved method. In addition, the pore size distribution (PSD) of soil changed from a bimodal distribution to a unimodal distribution, as shown by the MIP test results. With similar values in total intrusion volume, porosity, and median pore diameter, the data show that by using this newly improved synchronous and alternate vacuum preloading method, the treatment of ultrasoft dredged fills can be more even, which successfully avoids the common problem of uneven settlement of the ground. DA - 2018/8// PY - 2018/8// DO - 10.1061/(ASCE)GM.1943-5622.0001220 VL - 18 IS - 8 SP - 04018086 J2 - Int. J. Geomech. LA - en OP - SN - 1532-3641 1943-5622 UR - http://dx.doi.org/10.1061/(ASCE)GM.1943-5622.0001220 DB - Crossref KW - Model tests KW - Soil improvement KW - Hydraulic fills KW - Vacuum preloading method KW - Prefabricated vertical drains KW - Cost effectiveness ER - TY - JOUR TI - Comparing the economic, energy, and environmental impacts of biodiesel versus petroleum diesel fuel use in construction equipment AU - Lewis, Phil AU - Karimi, Boshra AU - Shan, Yongwei AU - Rasdorf, William T2 - International Journal of Construction Education and Research AB - Advocates for biodiesel claim that it is a clean, renewable, and cost effective fuel that provides economic and environmental benefits while easing the energy impacts of petroleum diesel; however, these claims are often anecdotal in nature and may not be based on empirical data. This paper presents the results of a case study that analyzes the economic, energy, and environmental impacts of biodiesel versus petroleum diesel fuel use in construction equipment. Using real world data, statistical comparisons were performed on a fleet of backhoes, motor graders, and wheel loaders. Hypothesis testing was used to determine whether or not there was a statistically significant difference between B20 and petroleum diesel in fuel prices, fuel use rates, and emissions rates. Scatterplots were developed to show how the two fuels are related to each other. Results indicated that there was no statistically significant difference between the national average prices of B20 and petroleum diesel; however, there were statistically significant differences between B20 and petroleum diesel for fuel use rates and emissions rates. It was concluded that B20 has slightly higher economic and energy impacts than petroleum diesel, but B20 did show potential for lower emissions rates for some pollutants. DA - 2018/6/14/ PY - 2018/6/14/ DO - 10.1080/15578771.2018.1483982 VL - 15 IS - 4 SP - 276-290 J2 - International Journal of Construction Education and Research LA - en OP - SN - 1557-8771 1550-3984 UR - http://dx.doi.org/10.1080/15578771.2018.1483982 DB - Crossref ER - TY - CONF TI - Real-Time Image-to-BIM Registration Using Perspective Alignment for Automated Construction Monitoring AU - Asadi, Khashayar AU - Han, Kevin T2 - Construction Research Congress 2018 C2 - 2018/3/29/ C3 - Construction Research Congress 2018 DA - 2018/3/29/ DO - 10.1061/9780784481264.038 PB - American Society of Civil Engineers SN - 9780784481264 UR - http://dx.doi.org/10.1061/9780784481264.038 DB - Crossref ER - TY - CONF TI - Assessment of Scour Potential under Wave Action Using ISEEP AU - Gabr, M. A. AU - Kebede, Y. A. AU - Kayser, M. F. AU - Dubbs, L. L. T2 - IFCEE 2018 AB - Field testing with ISEEP was conducted at Jennette’s Pier, located in Nags Head, NC. The Pier is subjected to high energy waves on a daily basis, and one of its piles was fitted with a Nortek acoustic beams device that monitors distance from the sensor to the seabed with time. An approach is introduced for assessing the wave-induced bed shear stress and stream power as a function of the wave parameters. The data from ISEEP are used along with the estimated stream power to assess the scour rate at one of the pier’s pile. The computed results are presented for wave heights of 1–5 m and wave periods that ranged from 8 to 17 s. ISEEP data indicted two subsurface sand layers with the lower layer having smaller detachment rate coefficient. This is confirmed by the fact that the lower layer has a coarser grain size distribution with shell fragments. Using an average wave period of 17 s and an average wave height of 3.5 m, results using the ISEEP data with the proposed approach illustrated the possibility of obtaining scour levels similar in magnitude to the monitored data. A direct comparison between measured and computed results with time was however not possible since the time resolution of the collected wave parameters was too coarse, and backfilling of the scour hole with loose sand occurred with time. C2 - 2018/6/6/ C3 - Innovations in Geotechnical Engineering DA - 2018/6/6/ DO - 10.1061/9780784481639.006 PB - American Society of Civil Engineers SN - 9780784481639 UR - http://dx.doi.org/10.1061/9780784481639.006 DB - Crossref ER - TY - JOUR TI - Factors affecting variability in PM 2.5 exposure concentrations in a metro system AU - Li, Zhiyuan AU - Che, Wenwei AU - Frey, H. Christopher AU - Lau, Alexis K.H. T2 - Environmental Research AB - The objectives of this study were to: (1) evaluate PM2.5 inflow to metro train cabins when doors open at stations; (2) assess the spatial and temporal variability in PM2.5 exposure concentration; and (3) quantify the relationship between in-cabin concentration versus outdoor and non-ambient PM2.5. We measured in-cabin PM2.5 concentrations using portable monitors at the door-side and center of a train cabin simultaneously on a Hong Kong metro line. In addition, platform and in-cabin pollutant concentrations near a train door were simultaneously measured. Short-term spikes in PM2.5 concentrations typically occur near train doors when doors open, related to inflow of ambient air aboveground and tunnel air underground. In-cabin PM2.5 exposure concentrations are typically lower away from the doors when the doors open. PM2.5 concentrations inside train cabins and on station platform operating above-ground are more influenced, compared to underground, by outdoor PM2.5. Moreover, non-ambient sources contribute approximately 50% of train in-cabin and station platform PM2.5 concentrations during underground operation. The results help more accurately quantify commuting PM2.5 exposure on a metro system, and can be used to improve population-based exposure simulation models. DA - 2018/1// PY - 2018/1// DO - 10.1016/J.ENVRES.2017.09.006 VL - 160 SP - 20-26 J2 - Environmental Research LA - en OP - SN - 0013-9351 UR - http://dx.doi.org/10.1016/J.ENVRES.2017.09.006 DB - Crossref KW - PM2.5 KW - Underground metro KW - Above-ground metro KW - Train in-cabin KW - Station platform KW - Hong KW - Kong ER - TY - JOUR TI - A review of factors impacting exposure to PM2.5, ultrafine particles and black carbon in Asian transport microenvironments AU - Kumar, Prashant AU - Patton, Allison P. AU - Durant, John L. AU - Frey, H. Christopher T2 - Atmospheric Environment AB - The World Health Organization estimates 3.7 million deaths in 2012 in low- and middle-income Asian countries due to outdoor air pollution. However, these estimates do not account for the higher exposures of specific particulate matter (PM) components – including fine particles (PM2.5), ultrafine particles (UFP) and black carbon (BC) – typical of transport microenvironments (TMEs). With the rapidly growing number of on-road vehicles in Asia, human exposure to PM is an increasing concern. The aim of this review article is to comprehensively assess studies of PM2.5, UFP, and BC in Asian TMEs in order to better understand the extent of exposure, the underlying factors leading to exposure, and how Asian exposures compare to those found in Europe and the United States of America (USA). The health impacts of exposure to PM2.5, UFP, and BC are described and the key factors that influence personal exposure in TMEs (i.e., walk, cycle, car, and bus) are identified. Instrumentation and measurement methods, exposure modeling techniques, and regulation are reviewed for PM2.5, UFP, and BC. Relatively few studies have been carried out in urban Asian TMEs where PM2.5, UFP, and BC had generally higher concentrations compared to Europe and USA. Based on available data, PM2.5 concentrations while walking were 1.6 and 1.2 times higher in Asian cities (average 42 μg m−3) compared to cities in Europe (26 μg m−3) and the USA (35 μg m−3), respectively. Likewise, average PM2.5 concentrations in car (74 μg m−3) and bus (76 μg m−3) modes in Asian cities were approximately two to three times higher than in Europe and American cities. UFP exposures in Asian cities were twice as high for pedestrians and up to ∼9-times as high in cars than in cities in Europe or the USA. Asian pedestrians were exposed to ∼7-times higher BC concentrations compared with pedestrians in the USA. Stochastic population-based models have yet to be applied widely in Asia but can be used to quantify inter-individual and inter-regional variability in exposures and to assess the contribution of TMEs to total exposures for multiple pollutants. The review also highlights specific gaps in the Asian TME data set that need to be filled since UFP and BC studies were rare as were studies of pedestrian and cyclist exposure. DA - 2018/8// PY - 2018/8// DO - 10.1016/J.ATMOSENV.2018.05.046 VL - 187 SP - 301-316 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/J.ATMOSENV.2018.05.046 DB - Crossref KW - Air pollution KW - Exposure KW - Asian cities KW - Transport microenvironments KW - Airborne ultrafine particles KW - Black carbon KW - PM2.5 ER - TY - CONF TI - Exploring Alignment Between Engineering Students’ Job Plans and Post-Graduation Outcomes AU - Rüde, Lenard AU - Harris, Angela AU - Gilmartin, Shannon AU - Sheppard, Sheri T2 - IEEE C2 - 2018/// C3 - 2018 IEEE Frontiers in Education Conference (FIE) DA - 2018/// SP - 1-9 ER - TY - PAT TI - US Patent No. 10,13,901: Systems for Emptying Pit Latrines and Septic Tanks AU - de los Reyes, F.L. III T2 - US Patent C2 - 2018/// DA - 2018/// PY - 2018/// ER - TY - CHAP TI - Seasonal Ensemble Forecast Post-processing AU - Wood, Andrew W. AU - Sankarasubramanian, A. AU - Mendoza, Pablo T2 - Handbook of Hydrometeorological Ensemble Forecasting PY - 2018/// DO - 10.1007/978-3-642-40457-3_37-1 SP - 1-27 OP - PB - Springer Berlin Heidelberg SN - 9783642404573 9783642404573 UR - http://dx.doi.org/10.1007/978-3-642-40457-3_37-1 DB - Crossref ER - TY - JOUR TI - Modeling the Irrigation Withdrawals Over the Coterminous US Using a Hierarchical Modeling Approach AU - Das, Priyam AU - Patskoski, Jason AU - Sankarasubramanian, A. T2 - Water Resources Research AB - Abstract Studies focusing on national/global water scarcity require water availability and water use to quantify the imbalance. In this regard, annual irrigation withdrawal data reported by the USGS every 5 years provide a valuable information on the water use patterns over the United States. This study develops an empirical model to estimate annual irrigation water withdrawal using irrigated area, climate information, and population as predictors. Given the hierarchy in the data sources, we propose a predictive linear hierarchical regression model to develop annual irrigation water withdrawal models using varying intercepts (VI) and varying intercepts and slopes (VIS) approaches. Estimates from hierarchical models are compared with pooled and unpooled classical regression models. Overall, both hierarchical models outperform the classical models with the adjusted R 2 between USGS‐reported and modeled withdrawal estimates being above 0.6 in most states using county and climate division level data. However, due to the spatial difference between the supply (rural areas) and demand (urban areas) for agriculture products, climate division level estimates exhibit a higher adjusted R 2 than county level estimates. The VIS model is able to capture local effects better, particularly for states whose irrigation withdrawal patterns significantly differ from the national pattern. The performance of the models is also validated by leaving out the entire nation's water‐use data out (i.e., leave‐one‐out cross‐validation) to ensure the reported skill is not due to overfitting. Split‐sample validation in predicting 2010 irrigation withdrawal also shows the potential of the developed hierarchical model in estimating the annual irrigation withdrawals for the years with no data within the once in 5 year USGS database. DA - 2018/6// PY - 2018/6// DO - 10.1029/2017wr021723 VL - 54 IS - 6 SP - 3769-3787 J2 - Water Resour. Res. LA - en OP - SN - 0043-1397 UR - http://dx.doi.org/10.1029/2017wr021723 DB - Crossref KW - irrigation withdrawal KW - hierarchical modeling KW - climate ER - TY - JOUR TI - Assessing the restoration time of surface water and groundwater systems under groundwater pumping AU - Seo, S. B. AU - Mahinthakumar, G. AU - Sankarasubramanian, A. AU - Kumar, M. T2 - Stochastic Environmental Research and Risk Assessment DA - 2018/6/12/ PY - 2018/6/12/ DO - 10.1007/S00477-018-1570-9 VL - 32 IS - 9 SP - 2741-2759 J2 - Stoch Environ Res Risk Assess LA - en OP - SN - 1436-3240 1436-3259 UR - http://dx.doi.org/10.1007/S00477-018-1570-9 DB - Crossref KW - Groundwater pumping KW - Streamflow depletion KW - Restoration time KW - Watershed resiliency ER - TY - JOUR TI - Role of Pacific SSTs in improving reconstructed streamflow over the coterminous US AU - Mukhopadhyay, Sudarshana AU - Patskoski, Jason M. AU - Sankarasubramanian, A. T2 - Scientific Reports AB - Reconstructed annual streamflows using tree-ring chronologies provide useful information on moisture availability during the pre-historic period, but they have limitations in estimating high flows due to the upper bound on soil water holding capacity and trees' metabolic growth limits. We propose a hybrid approach that uses tree-ring chronologies and climatic indices for improving high flows in 301 basins whose annual streamflows are modulated by ENSO and/or PDO. The hybrid decomposition approach relies on separating the moisture supply into the basin as outside-the-region moisture and within-the-region moisture with the former being estimated by SST indices and the latter being estimated by tree-ring chronologies. Analyses over the 301 stations from coterminous US show that the proposed approach improves the high flows and improves the overall error in the reconstructed streamflows. Potential utility of the improved reconstructed annual streamflows with improved high flows is also discussed. DA - 2018/3/21/ PY - 2018/3/21/ DO - 10.1038/s41598-018-23294-6 VL - 8 IS - 1 J2 - Sci Rep LA - en OP - SN - 2045-2322 UR - http://dx.doi.org/10.1038/s41598-018-23294-6 DB - Crossref ER - TY - JOUR TI - Evaluation of Waste Eggshells for Adsorption of Copper from Synthetic and Swine Wastewater AU - Hess, Brianna J. AU - Kolar, Praveen AU - Classen, John J. AU - Knappe, Detlef AU - Cheng, Jay J. T2 - Transactions of the ASABE AB - Abstract. Biomass-derived adsorbents are an attractive alternative to conventional water treatment methods. This study evaluated eggshells produced by the liquid egg and food processing industry for the adsorption of copper from aqueous systems. Research objectives were to (1) determine copper adsorption mechanisms and (2) evaluate copper adsorption by eggshells for the treatment of wastewater. Batch experiments were performed by contacting eggshells with copper solutions to obtain equilibrium, kinetic, and thermodynamic data to determine removal mechanisms and maximum adsorption capacity. Results suggested that the adsorption of copper followed a second-order kinetic model with a theoretical maximum adsorption capacity of 4.3 mg g -1 (20°C). In addition, eggshell adsorption was found to be a favorable process, with an activation energy of approximately 27 to 29 kJ mol -1 , and followed similar mechanisms as its calcite analog. Data indicated that slightly acidic (pH = 6) to near-neutral pH conditions enhanced adsorption of copper. Additional experiments were performed using swine lagoon wastewater to evaluate the efficacy of eggshells to treat copper from lagoon wastewater. The data suggested that unmodified eggshells were effective for application in swine lagoon systems only under acidic conditions (pH = 4). Further research is needed to modify eggshells that can adsorb copper in lagoon wastewater at neutral and alkaline pH. Keywords: Adsorption, Copper, Eggshell, Swine lagoon, Water. DA - 2018/// PY - 2018/// DO - 10.13031/trans.12599 VL - 61 IS - 3 SP - 967-976 LA - en OP - SN - 2151-0040 UR - http://dx.doi.org/10.13031/trans.12599 DB - Crossref KW - Adsorption KW - Copper KW - Eggshell KW - Swine lagoon KW - Water ER - TY - JOUR TI - Recently Detected Drinking Water Contaminants: GenX and Other Per- and Polyfluoroalkyl Ether Acids AU - Hopkins, Zachary R. AU - Sun, Mei AU - DeWitt, Jamie C. AU - Knappe, Detlef R.U. T2 - Journal - American Water Works Association AB - For several decades, a common processing aid in the production of fluoropolymers was the ammonium salt of perfluorooctanoic acid (PFOA). Because PFOA is persistent, bioaccumulative, and toxic, its production and use are being phased out in the United States. In 2009, the US Environmental Protection Agency stipulated conditions for the manufacture and commercial use of GenX, a PFOA replacement. While GenX is produced for commercial purposes, the acid form of GenX is also generated as a byproduct during the production of fluoromonomers. The discovery of high concentrations of GenX and related perfluoroalkyl ether acids (PFEAs) in the Cape Fear River and in finished drinking water of more than 200,000 North Carolina residents required quick action by researchers, regulators, public health officials, commercial laboratories, drinking water providers, and consulting engineers. Information about sources and toxicity of GenX as well as an analytical method for the detection of GenX and eight related PFEAs is presented. GenX/PFEA occurrence in water and GenX/PFEA removal by different drinking water treatment processes are also discussed. DA - 2018/6/14/ PY - 2018/6/14/ DO - 10.1002/awwa.1073 VL - 110 IS - 7 SP - 13-28 J2 - Journal - American Water Works Association LA - en OP - SN - 0003-150X UR - http://dx.doi.org/10.1002/awwa.1073 DB - Crossref KW - emerging per- and polyfluoroalkyl substances KW - hexafluoropropylene oxide dimer acid (HFPO-DA) KW - Nafion by-products KW - industrial wastewater KW - unregulated contaminants ER - TY - JOUR TI - Application and testing of risk screening tools for nanomaterial risk analysis AU - Grieger, Khara AU - Bossa, Nathan AU - Levis, James W. AU - von Borries, Kerstin Johanna Felicitas AU - Strader, Phillip AU - Cuchiara, Maude AU - Hendren, Christine Ogilvie AU - Hansen, Steffen Foss AU - Jones, Jacob L. T2 - Environmental Science: Nano AB - This study applies and tests new risk screening tools for engineered nanomaterials and highlights key findings. DA - 2018/// PY - 2018/// DO - 10.1039/C8EN00518D VL - 5 IS - 8 SP - 1844-1858 J2 - Environ. Sci.: Nano LA - en OP - SN - 2051-8153 2051-8161 UR - http://dx.doi.org/10.1039/C8EN00518D DB - Crossref ER - TY - JOUR TI - Proposing and Validating a New Way of Construction Hazard Recognition Training in Academia: Mixed-Method Approach AU - Tixier, Antoine J.-P. AU - Albert, Alex AU - Hallowell, Matthew R. T2 - Practice Periodical on Structural Design and Construction AB - The presented research proposes and experimentally validates a novel energy-based training module aimed at rapidly improving hazard-recognition skills in civil, environmental, and architectural engineering (CEAE) students. The module is based on the established theory that every construction hazard is fundamentally related to the unwanted release of one or more energy sources. Eighty-four members of a CEAE undergraduate class were participants during a three-week experiment. Adopting a rigorous A-B experimental design and validated protocol to measure hazard recognition, the study found the module increased students’ hazard-recognition skills by 67.8% on average (p < 0.001), with a lasting effect over time, while a standard lecture based on Occupational Safety and Health Administration (OSHA) training was found to be not significantly effective. Qualitative feedback gathered in the form of textual learning logs corroborated the quantitative findings. The study findings suggest that OSHA training may be complemented with components of the proposed method to improve hazard-recognition levels. DA - 2018/2// PY - 2018/2// DO - 10.1061/(asce)sc.1943-5576.0000347 VL - 23 IS - 1 SP - 04017027 J2 - Pract. Period. Struct. Des. Constr. LA - en OP - SN - 1084-0680 1943-5576 UR - http://dx.doi.org/10.1061/(asce)sc.1943-5576.0000347 DB - Crossref ER - TY - JOUR TI - Placing an ensemble of pressure sensors for leak detection in water distribution networks under measurement uncertainty AU - Raei, Ehsan AU - Shafiee, M. Ehsan AU - Nikoo, Mohammad Reza AU - Berglund, Emily T2 - Journal of Hydroinformatics AB - Abstract Large volumes of water are wasted through leakage in water distribution networks, and early detection of leakages is important to minimize lost water. Pressure sensors can be placed in a network to detect changes in pressure that indicate the presence of a new leak. This study presents a new approach for placing a set of pressure sensors by creating a list of candidate locations based on sensitivity to leaks that are simulated at all potential nodes in a network. The selection of a set of sensors is explored for two objectives, which are the minimization of the number of sensors and the time of detection. The non-dominated sorting genetic algorithm (NSGA-II) is used to explore trade-offs between these objectives. The effect of measurement uncertainty on the selection of sensor locations is explored by identifying alternative non-dominated fronts for different values for sensor error. The evolutionary algorithm-based approach is applied and demonstrated for the C-Town water network. DA - 2018/12/24/ PY - 2018/12/24/ DO - 10.2166/hydro.2018.032 VL - 21 IS - 2 SP - 223-239 LA - en OP - SN - 1464-7141 1465-1734 UR - http://dx.doi.org/10.2166/hydro.2018.032 DB - Crossref KW - genetic algorithm KW - leak detection KW - NSGA-II KW - pressure sensors KW - uncertainty ER - TY - JOUR TI - Exploring indicators for fatigue cracking in hot mix asphalt pavements using simplified-viscoelastic continuum damage theory AU - Mensching, David J. AU - Daniel, Jo Sias AU - Underwood, B. Shane T2 - Road Materials and Pavement Design AB - Fatigue cracking in asphalt pavements results in decreased ride quality, decreased fuel economy, and provides an avenue for intrusion of water. Since the current asphalt mixture design relies primarily on proportioning of component materials, performance is not considered directly. An advancement in technology is to design through direct material property assessment and correlations to field performance, a performance-based mixture design. The objectives of this paper are to: (1) relate mixture stiffness, fatigue, and pavement system characteristics together for use in the performance-based mixture design; (2) identify a Simplified-Viscoelastic Continuum Damage (S-VECD) model output parameter which produces the most separation between poorly and satisfactorily performing structures when combined with dynamic modulus and phase angle information; and (3) evaluate the impact of reclaimed asphalt pavement on the performance of the indicator. A pavement response model was coupled with the S-VECD analysis to determine the fatigue life using a representative pavement structure. Results show a relationship exists between the fatigue life of the pavement system, the dynamic modulus and phase angle, as well as an energy-based index. This approach holds promise because of its reliance on material attributes that can be derived on one testing machine. The model parameters from dynamic modulus and direct tension cyclic fatigue testing can also be incorporated into performance prediction software, further enhancing the appeal of a performance specification using the approach described in this study. DA - 2018/1/8/ PY - 2018/1/8/ DO - 10.1080/14680629.2018.1418713 VL - 19 IS - 3 SP - 536-545 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2018.1418713 DB - Crossref KW - hot mix asphalt KW - fatigue KW - viscoelastic continuum damage KW - reclaimed asphalt pavement ER - TY - JOUR TI - Effect of Synthetic Fiber State on Mechanical Performance of Fiber Reinforced Asphalt Concrete AU - Noorvand, Hossein AU - Salim, Ramadan AU - Medina, Jose AU - Stempihar, Jeffrey AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - It has been recognized that there exists a potential benefit from using synthetic fibers to reinforce asphalt mixtures. In these mixtures, the state of the fibers may play an essential role in their reinforcement function. This study aims to quantify the state of synthetic fiber distribution for two different aramid fiber–based asphalt mixtures and then show the impacts of fiber dispersion on modulus, rutting, and fatigue performance of each asphalt mixture in comparison with one another and with respect to an equivalent non-reinforced asphalt mixture. Both a quantitative and qualitative assessment of aramid fibers distribution as well as state of fiber are investigated using a fiber extraction procedure and microscopy imaging, respectively. The results suggested that a higher level of micro-fibrillation as well as high distribution of aramid fibers improved the rutting resistance of asphalt mixtures, while the distribution level of aramid fibers and fibers state did not affect the modulus and fatigue. These results are specific to the mixture studied but provide the first objective and detailed study describing fiber state, fiber dispersion, and performance. DA - 2018/7/13/ PY - 2018/7/13/ DO - 10.1177/0361198118787975 VL - 2672 IS - 28 SP - 42-51 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198118787975 DB - Crossref ER - TY - JOUR TI - Interpreting Stress Sensitivity in the Multiple Stress Creep and Recovery Test AU - Stempihar, Jeffrey AU - Gundla, Akshay AU - Underwood, B. Shane T2 - Journal of Materials in Civil Engineering AB - The original intent of the Jnrdiff limit applied to multiple stress creep and recovery test results was to ensure that an asphalt binder does not fail if, under real-world application, it experienced higher stresses or temperatures than what was considered in the laboratory. In recent years, challenges meeting the Jnrdiff specification for asphalt binders with low Jnr3.2 (mainly less than 0.5 kPa−1) have been documented, with reported Jnrdiff values greater than 400% in some cases. This paper presents an argument that Jnrdiff is an inaccurate representation of stress sensitivity, unfairly penalizes asphalt binders with low Jnr3.2, and lacks correlation with expected changes in field rutting performance. A new parameter that more appropriately describes stress sensitivity, Jnrslope, is presented. Jnrslope shows a better performance-based relationship to expected changes in rutting and more accurately ranks the study asphalt binders than Jnrdiff. Jnrslope also demonstrates the ability to capture changes in Jnr3.2 with respect to increases in test temperature. Finally, a conceptual, performance-based Jnrslope specification limit is presented. Overall, Jnrslope provides an alternate parameter to accurately interpret and describe stress and temperature sensitivity and demonstrates potential as a performance-based parameter. DA - 2018/2// PY - 2018/2// DO - 10.1061/(ASCE)MT.1943-5533.0002153 VL - 30 IS - 2 SP - 04017283 J2 - J. Mater. Civ. Eng. LA - en OP - SN - 0899-1561 1943-5533 UR - http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0002153 DB - Crossref ER - TY - JOUR TI - Estimation of Asphalt Concrete Modulus Using the Ultrasonic Pulse Velocity Test AU - Medina, Jose Roberto AU - Underwood, B. Shane AU - Mamlouk, Michael T2 - Journal of Transportation Engineering, Part B: Pavements AB - The mechanical dynamic modulus test was used to determine the dynamic moduli of hot-mix asphalt (HMA) with and without different types of fibers, and master curves were developed. The ultrasonic pulse velocity (UPV) test was then conducted on the same specimens to estimate the dynamic moduli across multiple temperatures, and master curves were developed. The Poisson’s ratios required for UPV modulus prediction were estimated for different reduced frequencies, and a sensitivity analysis on their effect on the modulus values was performed. The master curves developed using the UPV moduli were superimposed on the mechanical test master curves and matched closely. Witczak’s predictive equation and the Hirsch model were also used to predict the dynamic modulus master curves. The UPV moduli closely matched the mechanical dynamic moduli better than those predicted from the Witczak or Hirsch models at intermediate and high reduced frequencies. An attempt was made to combine the UPV modulus prediction with the Witczak and Hirsch models to improve moduli estimation at low reduced frequencies. Typical mechanical test methods are time consuming and require an expensive load frame and instrumentation setup. The UPV test requires less time, and the equipment needed is relatively inexpensive. Using the UPV test in combination with either the Witczak or Hirsch model is recommended as a lower-cost alternative to develop the master curves of the HMA dynamic moduli. DA - 2018/6// PY - 2018/6// DO - 10.1061/JPEODX.0000036 VL - 144 IS - 2 SP - 04018008 J2 - J. Transp. Eng., Part B: Pavements LA - en OP - SN - 2573-5438 2573-5438 UR - http://dx.doi.org/10.1061/JPEODX.0000036 DB - Crossref KW - Ultrasonic pulse velocity KW - Dynamic modulus KW - Poisson's ratio KW - Hirsch model KW - Witczak model ER - TY - JOUR TI - Effect of Loading Waveform Pattern and Rest Period on Fatigue Life of Asphalt Concrete Using Viscoelastic Continuum Damage Model AU - Zeiada, Waleed Abdelaziz AU - Gudipudi, Padmini P. AU - Underwood, B. Shane AU - Souliman, Mena I. T2 - Transportation Research Record: Journal of the Transportation Research Board AB - Fatigue cracking is one of the most critical types of distress in asphalt pavements and is due to actions of repetitive traffic loading over time. The fatigue life of asphalt concrete is often estimated from laboratory experiments where the performance depends directly on the test method, loading conditions, temperature, rest period, and aging in addition to the composition and properties of the mixture itself. The uniaxial fatigue test has become a popular method for developing constitutive models that describe the fatigue behavior of asphalt concrete mixture owing to the uniform states of stress across the specimen section. This study investigates the effect of the loading waveform (sinusoidal versus haversine) and rest period (continuous versus intermittent) on the laboratory fatigue life of asphalt concrete mixtures. The fatigue analysis was performed using the simplified viscoelastic continuum damage (S-VECD) approach where the damage characteristic (C-S) curves were established for all the cases, and then used to estimate the fatigue laws through simulated predictions. The proposed uniaxial fatigue test and analysis method were able to determine the fatigue life relationships of asphalt concrete mixture at different waveform and rest period conditions with a reduced testing time compared to other traditional testing and analysis methods. Overall, both rest period and waveform pattern were found to affect the laboratory fatigue life of asphalt concrete mixture. Model predictions show that pulse-rest loading yields an equivalent fatigue life to continuous loading at strain values that are approximately four times greater. DA - 2018/5/22/ PY - 2018/5/22/ DO - 10.1177/0361198118773892 VL - 2672 IS - 28 SP - 451-461 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198118773892 DB - Crossref ER - TY - JOUR TI - Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part I AU - Lucas, Donald AU - Petty, Sara M. AU - Keen, Olya AU - Luedeka, Bob AU - Schlummer, Martin AU - Weber, Roland AU - Barlaz, Morton AU - Yazdani, Ramin AU - Riise, Brian AU - Rhodes, James AU - Nightingale, Dave AU - Diamond, Miriam L. AU - Vijgen, John AU - Lindeman, Avery AU - Blum, Arlene AU - Koshland, Catherine P. T2 - Environmental Engineering Science AB - Flame retardants (FRs) are added to foams and plastics to comply with flammability standards and test requirements in products for household and industrial uses. When these regulations were implemented, potential health and environmental impacts of FR use were not fully recognized or understood. Extensive research in the past decades reveal that exposure to halogenated FRs, such as those used widely in furniture foam, is associated with and/or causally related to numerous health effects in animals and humans. While many of the toxic FRs have been eliminated and replaced by other FRs, existing products containing toxic or potentially toxic chemical FRs will remain in use for decades, and new products containing these and similar chemicals will permeate the environment. When such products reach the end of their useful life, proper disposal methods are needed to avoid health and ecological risks. To minimize continued human and environmental exposures to hazardous FR chemicals from discarded products, waste management technologies and processes must be improved. This review discusses a wide range of issues associated with all aspects of the use and responsible disposal of wastes containing FRs, and identifies basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes. DA - 2018/6// PY - 2018/6// DO - 10.1089/ees.2017.0147 VL - 35 IS - 6 SP - 573-587 J2 - Environmental Engineering Science LA - en OP - SN - 1557-9018 UR - http://dx.doi.org/10.1089/ees.2017.0147 DB - Crossref KW - disposal KW - flame retardants KW - foams KW - plastics ER - TY - JOUR TI - Real-time indoor measurement of health and climate-relevant air pollution concentrations during a carbon-finance-approved cookstove intervention in rural India AU - Kelp, Makoto M. AU - Grieshop, Andrew P. AU - Reynolds, Conor C.O. AU - Baumgartner, Jill AU - Jain, Grishma AU - Sethuraman, Karthik AU - Marshall, Julian D. T2 - Development Engineering AB - Biomass combustion in residential cookstoves is a major source of air pollution and a large contributor to the global burden of disease. Carbon financing offers a potential funding source for health-relevant energy technologies in low-income countries. We conducted a randomized intervention study to evaluate air pollution impacts of a carbon-finance-approved cookstove in rural South India. Prior research on this topic often has used time-integrated measures of indoor air quality. Here, we employed real-time monitors (∼24 h measurement at ∼ minute temporal resolution), thereby allowing investigation of minutely and hourly temporal patterns. We measured indoor concentrations of fine particulate matter (PM2.5), black carbon (BC) and carbon monoxide (CO) in intervention households (used newer, rocket-type stoves) and control households (“nonintervention”; continued using traditional open fire stoves). Some intervention households elected not to use only the new, intervention stoves (i.e., elected not to follow the study-design protocol); we therefore conducted analysis for “per protocol” versus “intent to treat.” We compared 24 h averages of air pollutants versus cooking hours only averages. Implementation of the per protocol intervention cookstove decreased median concentrations of CO (by 1.5 ppm (2.8 − 1.3; control − per protocol), p = 0.28) and PM2.5 (by 148 μg/m3 (365 − 217), p = 0.46) but increased BC concentration (by 39 μg/m3 (26 − −12), p < 0.05) and the ratio of BC/PM2.5 (by 0.25 (−0.28 − −0.03), p < 0.05) during cooking-relevant hours-of-day relative to controls. Calculated median effective air exchange rates based on decay in CO concentrations were stable between seasons (season 1: 2.5 h−1, season 2: 2.8 h−1). Finally, we discuss an analytical framework for evaluating real-time indoor datasets with limited sample sizes. For the present study, use of real-time (versus time-averaged) equipment substantially reduced the number of households we were able to monitor. DA - 2018/// PY - 2018/// DO - 10.1016/j.deveng.2018.05.001 VL - 3 SP - 125-132 J2 - Development Engineering LA - en OP - SN - 2352-7285 UR - http://dx.doi.org/10.1016/j.deveng.2018.05.001 DB - Crossref ER - TY - JOUR TI - Fecal Contamination on Produce from Wholesale and Retail Food Markets in Dhaka, Bangladesh AU - Harris, Angela R. AU - Islam, Mohammad Aminul AU - Unicomb, Leanne AU - Boehm, Alexandria B. AU - Luby, Stephen AU - Davis, Jennifer AU - Pickering, Amy J. T2 - The American Journal of Tropical Medicine and Hygiene AB - Fresh produce items can become contaminated with enteric pathogens along the supply chain at the preharvest (e.g., irrigation water, soil, fertilizer) or postharvest (e.g., vendor handling or consumer handling) stages. This study assesses the concentrations of fecal indicator bacteria Escherichia coli, enterococci (ENT), and Bacteriodales on surfaces of carrots, eggplants, red amaranth leaves, and tomatoes obtained from both a wholesale market (recently harvested) and neighborhood retail markets in Dhaka, Bangladesh. We detected E. coli in 100% of carrot and red amaranth rinses, 92% of eggplant rinses, and 46% of tomato rinses. Using a molecular microbial source tracking assay, we found that 32% of produce samples were positive for ruminant fecal contamination. Fecal indicator bacteria were more likely to be detected on produce collected in retail markets compared with that in the wholesale market; retail market produce were 1.25 times more likely to have E. coli detected (P = 0.03) and 1.24 times more likely to have ENT detected (P = 0.03) as compared with wholesale market produce. Bacteriodales was detected in higher concentrations in retail market produce samples compared with wholesale market produce samples (0.40 log10 gene copies per 100 cm2 higher, P = 0.03). Our results suggest that ruminant and general fecal contamination of produce in markets in Dhaka is common, and suggest that unsanitary conditions in markets are an important source of produce fecal contamination postharvest. DA - 2018/1/10/ PY - 2018/1/10/ DO - 10.4269/ajtmh.17-0255 VL - 98 IS - 1 SP - 287-294 LA - en OP - SN - 0002-9637 1476-1645 UR - http://dx.doi.org/10.4269/ajtmh.17-0255 DB - Crossref ER - TY - CONF TI - Preliminary tests of sensors to detect sewer network blockages AU - Curran, T.P. AU - Broderick, C. AU - Ducoste, J. AB - Abstract. Sewer blockages are a major problem in cities worldwide; these blockages are usually caused by a combination of fat, oil and grease waste and sanitary items that enter the network. This paper reports on preliminary tests of sensors to detect sewer network blockages in order to develop an advance warning system. Data from an ultrasonic level sensor were somewhat inconsistent while temperature records seem to be make more sense. The data capture level varied from 70-88% compared to what was originally planned, so data gaps are a concern. Further analysis is required along with testing of other sensors to determine which combinations work best. C2 - 2018/// C3 - ASABE 2018 Annual International Meeting DA - 2018/// DO - 10.13031/aim.201801691 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85054187336&partnerID=MN8TOARS ER - TY - CHAP TI - Vignette AU - Dietrich, Joel C. T2 - Disaster Epidemiology PY - 2018/// DO - 10.1016/B978-0-12-809318-4.00020-4 SP - 153-156 OP - PB - Elsevier SN - 9780128093184 UR - http://dx.doi.org/10.1016/B978-0-12-809318-4.00020-4 DB - Crossref ER - TY - JOUR TI - Distributed optimization and coordination algorithms for dynamic speed optimization of connected and autonomous vehicles in urban street networks AU - Tajalli, Mehrdad AU - Hajbabaie, Ali T2 - Transportation research part C: emerging technologies AB - Dynamic speed harmonization has shown great potential to smoothen the flow of traffic and reduce travel time in urban street networks. The existing methods, while providing great insights, are neither scalable nor real-time. This paper develops Distributed Optimization and Coordination Algorithms (DOCA) for dynamic speed optimization of connected and autonomous vehicles in urban street networks to address this gap. DOCA decomposes the nonlinear network-level speed optimization problem into several sub-network-level nonlinear problems thus, it significantly reduces the problem complexity and ensures scalability and real-time runtime constraints. DOCA creates effective coordination in decision making between each two sub-network-level nonlinear problems to push solutions towards optimality and guarantee attaining near-optimal solutions. DOCA is incorporated into a model predictive control approach to allow for additional consensus between sub-network-level problems and reduce the computational complexity further. We applied the proposed solution technique to a real-world network in downtown Springfield, Illinois and observed that it was scalable and real-time while finding solutions that were at most 2.7% different from the optimal solution of the problem. We found significant improvements in network operations and considerable reductions in speed variance as a result of dynamic speed harmonization. DA - 2018/// PY - 2018/// DO - 10.1016/j.trc.2018.07.012 VL - 95 SP - 497-515 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85051259651&partnerID=MN8TOARS ER - TY - JOUR TI - Dynamic speed harmonization in connected urban street networks AU - Tajalli, Mehrdad AU - Hajbabaie, Ali T2 - Computer-Aided Civil and Infrastructure Engineering AB - Abstract Connected vehicle technology, the Internet of Things, and other advanced communication technologies create possibilities to facilitate the movement of vehicles through transportation networks and reduce their travel time. Harmonizing the speed of vehicles in different network links not only yields a more efficient network capacity utilization, but also regulates the movement of vehicles to achieve a “smoother” flow of traffic. This study develops a mathematical nonlinear formulation for dynamic speed harmonization in urban street networks aiming at improving traffic operations. We have converted the nonlinear problem into a linear program utilizing the fundamental flow–density relationship and developed a model predictive control approach to account for stochastic changes in traffic demand and further improve the efficiency of the developed solution algorithm. Results showed that the algorithm efficiently found dynamic optimal advisory speeds on various network links, and speed harmonization significantly reduced the travel time (up to 5.4%), speed variance (19.8%–29.4%), and the number of stops (8.3%–18.5%), while increasing the average speed (up to 5.9%) and the number of completed trips (up to 4%) in our case study network under all tested demand patterns. DA - 2018/// PY - 2018/// DO - 10.1111/mice.12360 VL - 33 IS - 6 SP - 510-523 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85043677737&partnerID=MN8TOARS ER - TY - JOUR TI - Dynamic traffic metering in urban street networks: Formulation and solution algorithm AU - Mohebifard, Rasool AU - Hajbabaie, Ali T2 - Transportation research part C: emerging technologies AB - Traffic metering offers great potential to reduce congestion and enhance network performance in oversaturated urban street networks. This paper presents an optimization program for dynamic traffic metering in urban street networks based on the Cell Transmission Model (CTM). We have formulated the problem as a Mixed-Integer Linear Program (MILP) capable of metering traffic at network gates with given signal timing parameters at signalized intersections. Due to the complexities of the MILP model, we have developed a novel and efficient solution approach that solves the problem by converting the MILP to a linear program and several CTM simulation runs. The solution algorithm is applied to two case studies under different conditions. The proposed solution technique finds solutions that have a maximum gap of 1% of the true optimal solution and guarantee the maximum throughput by keeping some vehicles at network gates and only allowing enough vehicles to enter the network to prevent gridlocks. This is confirmed by comparing the case studies with and without traffic metering. The results in an adapted real-world case study network show that traffic metering can increase network throughput by 4.9–38.9% and enhance network performance. DA - 2018/// PY - 2018/// DO - 10.1016/j.trc.2018.04.027 VL - 93 SP - 161-178 UR - https://doi.org/10.1016/j.trc.2018.04.027 KW - Traffic metering KW - Perimeter control KW - Mixed integer linear programming KW - Optimization KW - Cell transmission model KW - Benders decomposition KW - Urban street networks ER - TY - JOUR TI - Development of a signal-head-free intersection control logic in a fully connected and autonomous vehicle environment AU - Mirheli, Amir AU - Hajibabai, Leila AU - Hajbabaie, Ali T2 - Transportation Research Part C: Emerging Technologies AB - Establishment of effective cooperation between vehicles and transportation infrastructure improves travel reliability in urban transportation networks. Lack of collaboration, however, exacerbates congestion due mainly to frequent stops at signalized intersections. It is beneficial to develop a control logic that collects basic safety message from approaching connected and autonomous vehicles and guarantees efficient intersection operations with safe and incident free vehicle maneuvers. In this paper, a signal-head-free intersection control logic is formulated into a dynamic programming model that aims to maximize the intersection throughput. A stochastic look-ahead technique is proposed based on Monte Carlo tree search algorithm to determine the near-optimal actions (i.e., acceleration rates) over time to prevent movement conflicts. Our numerical results confirm that the proposed technique can solve the problem efficiently and addresses the consequences of existing traffic signals. The proposed approach, while completely avoids incidents at intersections, significantly reduces travel time (ranging between 59.4% and 83.7% when compared to fixed-time and fully-actuated control strategies) at intersections under various demand patterns. DA - 2018/// PY - 2018/// DO - 10.1016/j.trc.2018.04.026 VL - 92 SP - 412-425 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85047272483&partnerID=MN8TOARS KW - Control logic KW - Autonomous intersection control KW - Monte Carlo tree search KW - Look-ahead model KW - Connected and autonomous vehicles KW - Dynamic programming ER - TY - JOUR TI - Long-term phosphorus loading and springtime temperatures explain interannual variability of hypoxia in a large temperate lake AU - Giudice, Dario Del AU - Zhou, Yuntao AU - Sinha, Eva AU - Michalak, Anna M T2 - Environmental Science & Technology AB - Anthropogenic eutrophication has led to the increased occurrence of hypoxia in inland and coastal waters around the globe. While low dissolved oxygen conditions are known to be driven primarily by nutrient loading and water column stratification, the relative importance of these factors and their associated time scales are not well understood. Here, we explore these questions for Lake Erie, a large temperate lake that experiences widespread annual summertime hypoxia. We leverage a three-decade data set of summertime hypoxic extent (1985-2015) and examine the role of seasonal and long-term nutrient loading, as well as hydrometeorological conditions. We find that a linear combination of decadal total phosphorus loading from tributaries and springtime air temperatures explains a high proportion of the interannual variability in average summertime hypoxic extent (R2 = 0.71). This result suggests that the lake responds primarily to long-term variations in phosphorus inputs, rather than springtime or annual loading as previously assumed, which is consistent with internal phosphorus loading from lake sediments likely being an important contributing mechanism. This result also demonstrates that springtime temperatures have a substantial impact on summertime hypoxia, likely by impacting the timing of onset of thermal stratification. These findings imply that management strategies based on reducing tributary phosphorus loading would take several years to reap full benefits, and that projected future increases in temperatures are likely to exacerbate hypoxia in Lake Erie and other temperate lakes. DA - 2018/1/4/ PY - 2018/1/4/ DO - 10.1021/acs.est.7b04730 VL - 1 ER - TY - JOUR TI - Accelerating Bayesian inference in hydrological modeling with a mechanistic emulator AU - Machac, David AU - Reichert, Peter AU - Rieckermann, Jörg AU - Giudice, Dario Del AU - Albert, Carlo T2 - Environmental Modelling & Software AB - As in many fields of dynamic modeling, the long runtime of hydrological models hinders Bayesian inference of model parameters from data. By replacing a model with an approximation of its output as a function of input and/or parameters, emulation allows us to complete this task by trading-off accuracy for speed. We combine (i) the use of a mechanistic emulator, (ii) low-discrepancy sampling of the parameter space, and (iii) iterative refinement of the design data set, to perform Bayesian inference with a very small design data set constructed with 128 model runs in a parameter space of up to eight dimensions. In our didactic example we use a model implemented with the hydrological simulator SWMM that allows us to compare our inference results against those derived with the full model. This comparison demonstrates that iterative improvements lead to reasonable results with a very small design data set. DA - 2018/7// PY - 2018/7// DO - 10.1016/j.envsoft.2018.07.016 VL - 7 ER - TY - JOUR TI - Dynamics of coarse and fine particle exposure in transport microenvironments AU - Kumar, Prashant AU - Rivas, Ioar AU - Singh, Anant Pratap AU - Ganesh, Vikas Julius AU - Ananya, Monirupa AU - Frey, H. Christopher T2 - NPJ CLIMATE AND ATMOSPHERIC SCIENCE AB - Abstract A significant fraction of daily personal exposure to air pollutants occurs during commuting in transport microenvironments (TMEs). We carried out systematic mobile monitoring on a pre-defined route to assess personal exposure levels of particulate matter (PM) in four TMEs (bus, car, cycle and walk). Measurements were made during morning peak (MP), afternoon off-peak (OP) and evening peak (EP) hours in a typical UK town, Guildford. The objectives were to quantify the real-time exposure to fine and coarse particles, identify the factors influencing their spatiotemporal variation and estimate the respiratory deposition doses (RDD). The mean PM 10 concentrations were 90 ± 63, 23 ± 9, 14 ± 17 and 63 ± 76 μg m −3 for bus, car, cycle and walk modes, respectively. The average ratios of PM 2.5 /PM 10 were 0.32, 0.90, 0.67 and 0.36 for bus, car, cycle and car journeys, respectively. The mean concentrations of coarse particles (PM 2.5-10 ) followed the trend: bus > walk > cycle > car. In contrast, mean concentrations of submicron (PM 1 ) and fine particles (PM 2.5 ) were usually high in the car while lowest for cyclists. RDD depend on the physical activity, particle size distribution and thus deposited fraction are not always proportional to the ambient concentration. RDD for coarse particles were largest for the walk mode (56 ± 14 μg h −1 ), followed by buses (31 ± 2 μg h −1 ), cycle (12 ± 3 μg h −1 ) and cars (1.2 ± 0.3 μg h −1 ). The corresponding RDD of fine particles were comparable for both walk (5.5 ± 0.3 μg h −1 ) and cycle (5.1 ± 1.2 μg h −1 ), followed by bus (4.1 ± 0.7 μg h −1 ) and car (2.0 ± 0.2 μg h −1 ). Car mode experienced both the least concentrations and RDD for coarse particles. It also had the lowest RDD for fine particles despite high concentrations. Physical activity of car commuters is modest compared with walking and cycling, which makes the rank ordering of RDD different than those of exposure concentrations. Hence the management of commuting exposures should consider potential dose and not just exposure concentration for curtailing adverse health effects related to commuting. RDD for pedestrian and cycle modes were not the lowest among the measured modes but opportunities such as an increased distance between the heavily trafficked roadways and pedestrians/cyclists should be considered in urban planning to reduce potential doses. DA - 2018/// PY - 2018/// DO - 10.1038/s41612-018-0023-y VL - 1 IS - 1 SP - SN - 2397-3722 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85048165474&partnerID=MN8TOARS ER - TY - JOUR TI - Modeling and Evaluating Traffic Flow at Sag Curves When Imposing Variable Speed Limits on Connected Vehicles AU - Nezafat, Reza Vatani AU - Beheshtitabar, Ehsan AU - Cetin, Mecit AU - Williams, Elizabeth AU - List, George F. T2 - TRANSPORTATION RESEARCH RECORD AB - Sag curves, road segments where the gradient changes from downwards to upwards, generally reduce the roadway capacity and cause congestion. This results from a change in longitudinal driving behavior when entering a sag curve as drivers tend to reduce speeds or increase headways as vehicles reach the uphill section. In this research, a control strategy is investigated through manipulating the speed of connected vehicles (CVs) in the upstream of the sag curve to avoid the formation of bottlenecks caused by the change in driver behavior. Traffic flow along a sag curve is simulated using the intelligent driver model (IDM), a time-continuous car-following model. A feedback control algorithm is developed for adjusting the approach speeds of CVs so that the throughput of the sag curve is maximized. Depending on the traffic density at the sag curve, adjustments are made for the speeds of the CVs. A simulation-based optimization method using a meta-heuristic algorithm is employed to determine the critical control parameters. Various market penetration rates for CVs are also considered in the simulations. Even at relatively low market penetration rates (e.g., 5–10%), significant improvements in travel times and throughput are observed. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118784169 VL - 2672 IS - 20 SP - 193-202 SN - 2169-4052 ER - TY - JOUR TI - Effects of the International Roughness Index and Rut Depth on Crash Rates AU - Mamlouk, Michael AU - Vinayakamurthy, Mounica AU - Underwood, B. Shane AU - Kaloush, Kamil E. T2 - Transportation Research Record: Journal of the Transportation Research Board AB - Pavement distresses directly affect ride quality, and indirectly contribute to driver distraction, vehicle operation, and accidents. In this study, analysis was performed on highways in the states of Arizona, North Carolina, and Maryland to investigate the relationship between accident rate and pavement ride quality (roughness) and rut depth. Two main types of data were collected: crash data from the accident records and International Roughness Index (IRI) and rut depth data from the pavement management system database in each state. Crash rates were calculated using the U.S. Department of Transportation method, which is the number of accidents per 100 million vehicle-miles of travel. Sigmoidal function regression analysis was performed to study the relationship between crash rate and both IRI and rut depth. In all cases, the crash rate did not show substantial increases until an IRI value of 210 inches/mile or a critical rut depth of 0.4 inches. When the IRI or rut depth increased above these values the crash rate increased. This is a key conclusion that provides empirically derived thresholds for IRI and rut depth to reducing the accident rate. DA - 2018/6/21/ PY - 2018/6/21/ DO - 10.1177/0361198118781137 VL - 2672 IS - 40 SP - 418-429 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198118781137 DB - Crossref ER - TY - JOUR TI - Characteristics and Temporal Stability of Recurring Bottlenecks AU - Ahmed, Ishtiak AU - Rouphail, Nagui M. AU - Tanvir, Shams T2 - TRANSPORTATION RESEARCH RECORD AB - This study applies and updates a method which identifies and quantifies the extent of traffic congestion from recurring freeway bottlenecks. Additionally, the spatiotemporal stability of bottlenecks over an extended period was tested. Over time congestion at bottlenecks may increase, may decrease, or may migrate to other nearby locations. Analysis of stability is important since prioritizing and applying treatments at bottlenecks is a multiyear process. In addition, a robust method for selecting sensitivity based parameters to identify and quantify bottleneck effects is presented. Subsequently, a systematic framework is developed for tracking and archiving the spatiotemporal changes in the recurring bottlenecks. The proposed method is demonstrated on a case study on Interstate 40 in North Carolina using three years of probe data. A congestion speed ratio detection threshold of 0.7 and a probability of activation threshold of 33% for the study area were determined from a sensitivity test to ascertain their recurrence. The method identified 13 bottlenecks with their impacts ranging from 35 to 3,278 mi-hours of congestion per year. Eight bottlenecks either newly emerged or had their queues merged or shifted between successive years. Even spatially stable bottlenecks had significant variation in their activation frequency and queue length. Exploration of the changes in bottleneck severity and locations revealed the influence of a long-term work zone in the area and the effect of the rapid growth in traffic demand. Local agencies can use this method to shortlist recurring bottlenecks and track changes to plan mitigation strategies. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118798991 VL - 2672 IS - 42 SP - 235-246 SN - 2169-4052 ER - TY - JOUR TI - Fatigue Performance Prediction of Asphalt Pavements with FlexPAVE (TM), the S-VECD Model, and D-R Failure Criterion AU - Wang, Yizhuang David AU - Keshavarzi, Behrooz AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Reliable predictions of asphalt materials and pavement performance are important elements in mixture design, mechanistic-empirical pavement design, and performance-related specifications. This paper presents FlexPAVE™, a pavement performance prediction program. FlexPAVE™ is a three-dimensional finite element program that is capable of moving load analysis under realistic climatic conditions. It utilizes the simplified viscoelastic continuum damage (S-VECD) model to predict asphalt pavement fatigue life. This S-VECD model currently incorporates the so-called G R failure criterion to define the failure of asphalt mixtures. In this study, a new failure criterion for the S-VECD model, designated as the D R criterion, has been developed to remedy some of the shortcomings of the G R failure criterion. This D R criterion has been implemented successfully in FlexPAVE TM . In this paper, FlexPAVE TM is used to simulate the fatigue performance of field test sections. These test sections include various pavement structures, such as perpetual pavements and accelerated load facility test pavements in the United States, South Korea, and China, as well as various materials, such as warm-mix asphalt, reclaimed asphalt pavement, and mixtures with modified binders. The D R -based FlexPAVE TM predictions have yielded good agreement with the field measurements and show more reasonable trends compared to predictions obtained using the G R failure criterion. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118756873 VL - 2672 IS - 40 SP - 217-227 SN - 2169-4052 ER - TY - JOUR TI - Validation and Calibration of Freeway Reliability Methodology in the Highway Capacity Manual: Method and Case Studies AU - Karmakar, Nabaruna AU - Aghdashi, Seyedbehzad AU - Rouphail, Nagui M. AU - Williams, Billy M. T2 - TRANSPORTATION RESEARCH RECORD AB - Traffic congestion costs drivers an average of $1,200 a year in wasted fuel and time, with most travelers becoming less tolerant of unexpected delays. Substantial efforts have been made to account for the impact of non-recurring sources of congestion on travel time reliability. The 6 th edition of the Highway Capacity Manual (HCM) provides a structured guidance on a step-by-step analysis to estimate reliability performance measures on freeway facilities. However, practical implementation of these methods poses its own challenges. Performing these analyses requires assimilation of data scattered in different platforms, and this assimilation is complicated further by the fact that data and data platforms differ from state to state. This paper focuses on practical calibration and validation methods of the core and reliability analyses described in the HCM. The main objective is to provide HCM users with guidance on collecting data for freeway reliability analysis as well as validating the reliability performance measures predictions of the HCM methodology. A real-world case study on three routes on Interstate 40 in the Raleigh-Durham area in North Carolina is used to describe the steps required for conducting this analysis. The travel time index (TTI) distribution, reported by the HCM models, was found to match those from probe-based travel time data closely up to the 80 th percentile values. However, because of a mismatch between the actual and HCM estimated incident allocation patterns both spatially and temporally, and the fact that traffic demands in the HCM methods are by default insensitive to the occurrence of major incidents, the HCM approach tended to generate larger travel time values in the upper regions of the travel time distribution. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118798723 VL - 2672 IS - 15 SP - 93-104 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060939515&partnerID=MN8TOARS ER - TY - JOUR TI - Application of a Discontinuous Form of Macroscopic Gazis-Herman-Rothery Model to Steady-State Freeway Traffic Stream Observations AU - Ahmed, Ishtiak AU - Williams, Billy M. AU - Samandar, M. Shoaib T2 - TRANSPORTATION RESEARCH RECORD AB - In this study, a two-regime, steady-state, traffic stream model is developed by applying the macroscopic Gazis–Herman–Rothery model to fixed sensor data on freeways. The uncongested and congested regimes are modeled discontinuously with an overlap range defined in terms of density. The overlap is important as various phenomena related to the change in traffic state can be modeled by introducing this overlap. Two empirical tools for removing non-stationary, mixed-state, and erroneous observations are applied at different stages of the model development process. Three constraints justified by the Highway Capacity Manual (HCM) were applied to fit the model so that the fitted parameters have reasonable and physically interpretable values. The proposed model is applied to one year of data (2013) obtained from fixed sensors located at five freeway basic segments near Raleigh, North Carolina. The resulting fundamental diagrams show that the fitted models reasonably represent the steady-state observations. Two forms of the freeway flow model described in the HCM were applied to the same observations to provide a continuous model comparison. Two statistical performance measures, mean squared error of flow rate and Bayesian Information Criterion, verify that the proposed model is preferable to the HCM models both in terms of fit alone and when considering the tradeoff between fit and model complexity. It is expected that the proposed discontinuous steady-state model will be useful to researchers and practitioners to study various site-specific freeway traffic stream characteristics. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118799166 VL - 2672 IS - 20 SP - 51-62 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060947455&partnerID=MN8TOARS ER - TY - JOUR TI - Evaluation of Chemical and Rheological Aging Indices to Track Oxidative Aging of Asphalt Mixtures AU - Rad, Farhad Yousefi AU - Elwardany, Michael D. AU - Castorena, Cassie AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Oxidative age hardening in asphalt binder leads to embrittlement. Embrittled asphalt is prone to fatigue and thermal cracking. Therefore, the ability to predict asphalt binder oxidative age hardening within a pavement throughout its service life could inform improved pavement material selection, design, and maintenance practices. Studying the evolution of oxidative aging requires the use of key properties to track oxidation levels, termed aging index properties (AIPs) here. The objective of this study is to identify suitable rheological and chemical AIPs to track oxidation levels in asphalt materials. A wide range of laboratory and field aged materials were evaluated in this study. A range of chemical AIPs determined by Fourier transform infrared spectroscopy (FTIR) absorbance peaks and areas were evaluated based on their correlation with laboratory aging duration. Rheological AIPs were evaluated based on the strength of their relationship to the chemical changes induced by oxidation. The rheological AIPs evaluated included the dynamic shear modulus, zero shear viscosity, Glover-Rowe parameter, and crossover modulus. The chemical AIP evaluation that most strongly correlated with laboratory aging duration is the carbonyl plus the sulfoxide absorbance peaks. The results indicate that both the dynamic shear modulus and Glover-Rowe parameter constitute rheological AIPs that relate directly to the chemical changes induced by oxidation. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118784138 VL - 2672 IS - 28 SP - 349-358 SN - 2169-4052 ER - TY - JOUR TI - Performance-Graded Specifications for Asphalt Emulsions Used in Chip Seal Preservation Treatments AU - Adams, Javon AU - Ilias, Mohammad AU - Castorena, Cassie AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - This paper details the development of a framework for emulsion performance-grade (EPG) specifications for chip seal treatments. Chip seals are preservation surface treatments that are designed to improve the condition of the pavement surface while mitigating deterioration of the overall pavement structure. Asphalt emulsions used in chip seals often are selected based on factors that are not necessarily related to performance. Aggregate loss and bleeding have been identified as the most critical chip seal distresses that are related to binder performance. Storage stability, sprayability, and drain-out have been determined to be the most critical constructability concerns. For this study, binder and mixture test methods were identified to reflect the failure mechanisms for each critical distress type. The emulsion residue test methods that were identified to capture chip seal performance are the multiple stress creep and recovery test for bleeding and the dynamic shear rheometer frequency sweep test for low-temperature aggregate loss. The fresh emulsion test methods that were identified to capture chip seal constructability are the three-step shear test and storage stability test. The proposed EPG specifications for the fresh emulsion properties that are related to constructability were developed using statistical analysis of the binder test results. The proposed EPG specifications for the residual binder properties were developed by defining the temperature-independent relationships between the emulsion residue properties and mixture performance that correspond to each critical distress. Preliminary specification limits were then established based on the values of the binder properties that correspond to the critical mixture performance thresholds. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118770169 VL - 2672 IS - 12 SP - 20-31 SN - 2169-4052 ER - TY - JOUR TI - Low-Temperature Emulsion Performance-Graded Specification for Chip Seals AU - Castorena, Cassie AU - Ilias, Mohammad AU - Adams, Javon AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Chip seals are applied to existing roadways to slow deterioration and improve pavement surface conditions without increasing the pavement’s structural capacity. Chip seals typically are comprised of asphalt emulsion and aggregate. Although it is well known that the properties of asphalt emulsion are critical to chip seal performance, the current specifications for these binders are empirical in nature and are not based on the properties that relate directly to chip seal performance. This study proposes emulsion performance-graded specifications that are designed to mitigate aggregate loss at low temperatures. To develop the proposed specifications, the research team executed an experimental plan to identify the residual binder properties that relate to chip seal aggregate loss at low temperatures. This research considered both fracture mechanics and rheology-based binder properties. Dynamic shear moduli, evaluated at critical phase angle values, demonstrated the strongest correlation to chip seal aggregate loss at low temperatures. Critical phase angle values were varied as a function of the low-temperature climatic emulsion performance grade of interest. This study also established preliminary specification limits for the dynamic shear modulus values based on critical chip seal performance thresholds. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118790133 VL - 2672 IS - 28 SP - 266-276 SN - 2169-4052 ER - TY - JOUR TI - Low-Temperature Vacuum Drying Procedure for Rapid Asphalt Emulsion Residue Recovery AU - Malladi, Haritha AU - Asnake, Meron AU - LaCroix, Andrew AU - Castorena, Cassie T2 - TRANSPORTATION RESEARCH RECORD AB - Asphalt emulsions are used extensively in tack coats and preservation surface treatments. The current specifications for asphalt emulsion residue recovery in AASHTO PP 72 are based on low-temperature evaporative drying. The shortest residue recovery procedure included in AASHTO PP 72 requires 6 h of conditioning in an oven to dry an emulsion. The ability to recover emulsion residues efficiently is of great interest given the ongoing efforts to develop emulsion performance-graded specifications based on residual binder properties. In this study, a rapid, vacuum drying technology was evaluated for asphalt emulsion residue recovery. The procedure enables the recovery of sufficient residual binder for dynamic shear rheometer (DSR) testing within 20–40 min. Five emulsions of different classifications were evaluated using both the vacuum drying procedure and the AASHTO PP 72 procedures. The vacuum drying procedure leads to similar water loss to the AASHTO PP 72 procedures. Based on the temperature-frequency sweep and multiple stress creep and recovery (MSCR) test results, the vacuum-dried residues are softer and more viscous than residues recovered using the AASHTO PP 72 procedures. Fourier transform infrared spectroscopy (FTIR) was performed to identify if oxidation levels could explain the observed in rheological trends. However, the results suggest no clear trend in the oxidation levels of residues recovered using AASHTO PP 72 compared with the rapid vacuum procedure. Future work is necessary to infer which method best reflects residual binders placed in the field. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118791913 VL - 2672 IS - 28 SP - 256-265 SN - 2169-4052 ER - TY - JOUR TI - Weigh Station Impact on Truck Travel Time Reliability: Results and Findings from a Field Study and a Simulation Experiment AU - Samandar, M. Shoaib AU - Williams, Billy M. AU - Ahmed, Ishtiak T2 - TRANSPORTATION RESEARCH RECORD AB - Weigh stations are necessary for safeguarding highway infrastructure by enforcing truck weight limits. However, mandating all trucks to stop at all weigh stations decreases travel time reliability. This decrease in travel time reliability adversely impacts the productivity of the trucking industry and to a lesser degree impacts personal travel reliability as well. This study, conducted at the Lumberton weigh station on Interstate 95 in North Carolina, quantifies the impact of weigh stations on truck travel time reliability. Truck travel times were observed over periods of weigh station operation and weigh station closure. Comparison of these two states sheds light on the variability in travel time caused by weigh station operation. Results show that when the weigh station is operational, truck travel time reliability degrades significantly. VISSIM microsimulation software was used to quantify the expected impact of weigh in motion (WIM) on truck travel time reliability assuming different scenarios of WIM truck bypass. The model results indicate that WIM technology does increase travel time reliability and provides benefits to both trucking companies and enforcement agencies. It was also found that increases in the proportion of WIM bypass result in increases in route travel time reliability. However, this simulation model improvement was not uniform, with the highest marginal improvement occurring in the 30%–40% WIM bypass range. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118791667 VL - 2672 IS - 9 SP - 120-129 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85052711188&partnerID=MN8TOARS ER - TY - JOUR TI - Highway Asset Deterioration Rates AU - Rasdorf, William AU - Almalki, Ali T2 - TRANSPORTATION RESEARCH RECORD AB - This paper is about highway asset deterioration rates. Typically, these are difficult to determine. However, using a data collection method adopted in North Carolina (and the resulting data obtained over a 5-year timespan), an approach was developed to determine accurate deterioration rates for several highway assets. This was not previously done, and thus, deterioration was not included as a factor in estimating future maintenance needs for these assets despite the ready availability of the necessary data. This paper focuses on unpaved shoulders and outlines how their deterioration rates were obtained and how such rates can also be obtained for other assets. The resulting deterioration rates are presented and compared over various road systems and geographical regions. With this new knowledge, deterioration rates can now be included in life cycle asset analysis, resulting in more accurate condition predictions and maintenance budgeting. The paper focuses on highway assets and does not address bridge or pavement maintenance. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118781136 VL - 2672 IS - 12 SP - 179-186 SN - 2169-4052 ER - TY - JOUR TI - Reliability Assessment Tool: Development and Prototype Testing AU - List, George F. AU - Rouphail, Nagui AU - Smith, Russell AU - Williams, Billy T2 - TRANSPORTATION RESEARCH RECORD AB - This paper presents a monitoring system that was developed to assess travel time reliability for observed operating conditions by utilizing traffic stream and non-transportation related data. A prototype was created for an interstate highway route in the Research Triangle region of North Carolina. It describes how the input datasets were obtained, the required data fusion procedures, how the data were analyzed to create the monitoring system outputs, and relevant insights obtained from the reliability monitoring system prototype. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118798296 VL - 2672 IS - 14 SP - 29-38 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060926457&partnerID=MN8TOARS ER - TY - JOUR TI - Effect of Light Duty Vehicle Performance on a Driving Style Metric AU - Tanvir, Shams AU - Frey, H. Christopher AU - Rouphail, Nagui M. T2 - TRANSPORTATION RESEARCH RECORD AB - Eco-driving involves alterations to driving style to improve energy efficiency. The observed driving style reflects the combined effects of roadway, traffic, driver, and vehicle performance. Although the effect of roadway and traffic characteristics can be inferred from microscale driving activity data, the effect of vehicle performance on driving style is not properly understood. This paper addresses two questions: (1) how different is an individual driver’s driving style when operating vehicles with differences in performance?; and (2) how dissimilar are the driving styles of different drivers when operating vehicles that have similar performance? To answer these questions, we have gathered microscale vehicle activity measurements from 17 controlled real-world driving schedules and two years of naturalistic driving data from five drivers. We also developed a metric for driving style termed “envelope deviation,” which is a distribution of gaps between microscale activity (1 Hz) and fleet average envelope. We found that there is significant inter-driver heterogeneity in driving styles when controlling for vehicle performance. However, no significant inter-vehicle heterogeneity was present in driving styles while controlling for the driver. Findings from this study imply that the choice of vehicle does not significantly alter the natural driving style of a driver. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118796070 VL - 2672 IS - 25 SP - 67-78 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060916631&partnerID=MN8TOARS ER - TY - JOUR TI - Optimization of the Laboratory Fabrication of Small Specimens for Asphalt Mixture Performance Testing AB - The use of 38-mm-diameter small specimens for uniaxial dynamic modulus and cyclic fatigue asphalt mixture performance testing offers a significant opportunity to improve the efficiency of laboratory-fabricated specimen testing because multiple test specimens can be extracted per Superpave gyratory-compacted (SGC) sample. This study seeks to optimize the procedure used for the extraction of small specimens from SGC samples for dynamic modulus and cyclic fatigue tests. To this end, small cylindrical specimens were cored horizontally and vertically from SGC samples and subjected to performance testing. The dynamic modulus and fatigue test results indicate that the effects of anisotropy are minimal. However, all of the horizontally extracted small specimens exhibited fatigue failure at the specimen ends, outside the range of the gauges; the failure was likely due to the peripheral air void gradients in the SGC samples. Therefore, the authors concluded that small specimens should be vertically cored from SGC samples for the laboratory fabrication of small specimens. Specifically, four small specimens were cored vertically from the inner 100 mm of SGC samples where the air void content is relatively uniform. Four mixtures with different nominal maximum aggregate sizes (NMASs) were used to prepare small specimens using the proposed extraction procedure. These specimens were subjected to dynamic modulus and cyclic fatigue testing. The results demonstrate an increase in specimen-to-specimen variability with an increase in NMAS, which also is expected in large specimen testing. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118790845 UR - http://dx.doi.org/10.1177/0361198118790845 ER - TY - JOUR TI - Improving the Reliability of Damage Characteristic Curves in the Simplified Viscoelastic Continuum Damage Model AB - One of the major advantages of the cyclic fatigue test (AASHTO TP 107) is that the results can be used to calibrate the Simplified Viscoelastic Continuum Damage (S-VECD) model, which is used for mechanistic pavement performance predictions. The crux of the S-VECD model is the damage characteristic curve, which has been shown to be independent of mode of loading, loading history, and temperature. Consequently, a model can be fitted to the damage characteristic curve and used to predict the damage response for any given loading history of interest using limited test results. AASHTO TP 107 currently lacks a specific procedure for fitting a model to the damage characteristic curve and evaluating the repeatability of test replicates. In this study, a robust and practical method is proposed for fitting a power law model to the damage characteristic curve. The proposed fitting method was verified using cyclic fatigue test results of 19 mixtures sourced from the United States, Canada, and South Korea. In addition, a means to evaluate the specimen-to-specimen variability of damage characteristic curves using a shape factor is proposed. Thresholds for acceptable variability in the shape factor were derived using confidence interval analysis and verified through FlexPAVE™ pavement performance predictions. The findings of this study can be used to improve the reliability of the damage characteristic curves derived from cyclic fatigue tests for pavement performance predictions. DA - 2018/12// PY - 2018/12// DO - 10.1177/0361198118797808 UR - http://dx.doi.org/10.1177/0361198118797808 ER - TY - RPRT TI - A National Model for Predicting Life Cycle Costs and Benefits of Intersection Control Alternatives AU - Findley, D.J. AU - Aghdashi, B. AU - Davis, J. AU - Cunningham, C. A3 - University of Maryland. National Transportation Center DA - 2018/3/30/ PY - 2018/3/30/ M1 - NTC2016-MU-R-03 PB - University of Maryland. National Transportation Center SN - NTC2016-MU-R-03 UR - http://ntc.umd.edu/node/169 ER - TY - JOUR TI - Integrating Larval Dispersal, Permitting, and Logistical Factors Within a Validated Habitat Suitability Index for Oyster Restoration AU - Puckett, Brandon J. AU - Theuerkauf, Seth J. AU - Eggleston, David B. AU - Guajardo, Rodney AU - Hardy, Craig AU - Gao, Jie AU - Luettich, Richard A. T2 - FRONTIERS IN MARINE SCIENCE AB - Habitat suitability index (HSI) models are increasingly used to guide ecological restoration. Successful restoration is a byproduct of several factors, including physical and biological processes, as well as permitting and logistical considerations. Rarely are factors from all of these categories included in HSI models, despite their combined relevance to common restoration goals such as population persistence. We developed a Geographic Information System (GIS)-based HSI for restoring persistent high-relief subtidal oyster (Crassostrea virginica) reefs protected from harvest (i.e., sanctuaries) in Pamlico Sound, North Carolina, USA. Expert stakeholder input identified 17 factors to include in the HSI. Factors primarily represented physical (e.g., salinity) and biological (e.g., larval dispersal) processes relevant to oyster restoration, but also included several relevant permitting (e.g., presence of seagrasses) and logistical (e.g., distance to restoration material stockpile sites) considerations. We validated the model with multiple years of oyster density data from existing sanctuaries, and compared HSI output with distributions of oyster reefs from the late 1800’s. Of the 17 factors included in the model, stakeholders identified four factors—salinity, larval export from existing oyster sanctuaries, larval import to existing sanctuaries, and dissolved oxygen—most critical to oyster sanctuary site selection. The HSI model provided a quantitative scale over which a vast water body (~6,000 km2) was narrowed down by 95% to a much smaller suite of optimal (top 1% HSI) and suitable (top 5% HSI) locations for oyster restoration. Optimal and suitable restoration locations were clustered in northeast and southwest Pamlico Sound. Oyster density in existing sanctuaries, normalized for time since reef restoration, was a positive exponential function of HSI, providing validation for the model. Only a small portion (10-20%) of historical reef locations overlapped with current, model-predicted optimal and suitable restoration habitat. We contend that stronger linkages between larval connectivity, landscape ecology, stakeholder engagement and spatial planning within HSI models can provide a more holistic, unified approach to restoration. DA - 2018/4/4/ PY - 2018/4/4/ DO - 10.3389/fmars.2018.00076 VL - 5 SP - SN - 2296-7745 KW - eastern oyster KW - Crassostrea virginica KW - population persistence KW - decision support tool KW - HSI KW - Pamlico Sound KW - larval connectivity ER - TY - JOUR TI - Evaluation of wait times and queue lengths at ferry terminals AU - Findley, Daniel J. AU - Anderson, Tracy J. AU - Bert, Steven A. AU - Nye, Timothy AU - Letchworth, Will T2 - RESEARCH IN TRANSPORTATION ECONOMICS AB - Transportation systems often require travelers to wait for service. Observational data from a wait-time study at ferry terminals demonstrate that the amount of time a vehicle waits to board a ferry is highly dependent on that vehicle's position in line. Queue psychology suggests that unexplained waits, uncertainty, and anxiety make wait times for individuals seem longer. Thus, the vehicle position and wait time relationship can be used to equip ferry service providers with the knowledge to inform and pacify passengers waiting to board a ferry. DA - 2018/11// PY - 2018/11// DO - 10.1016/j.retrec.2018.06.009 VL - 71 SP - 27-33 SN - 1875-7979 UR - https://doi.org/10.1016/j.retrec.2018.06.009 KW - Ferry KW - Tourism KW - Travel KW - Waiting times KW - Queuing time KW - Time perception KW - Wait perception KW - Queue length KW - Queuing KW - Travel time KW - Ferry terminal KW - Wait anxiety KW - Queue anxiety KW - Information KW - Customer information KW - Travel information ER - TY - JOUR TI - Beach Management Practices and Occupation Dynamics: An Agent-Based Modeling Study for the Coastal Town of Nags Head, NC, USA AU - Karanci, Ayse AU - Velasquez-Montoya, Liliana AU - Paniagua-Arroyave, Juan F. AU - Adams, Peter N. AU - Overton, Margery F. T2 - BEACH MANAGEMENT TOOLS - CONCEPTS, METHODOLOGIES AND CASE STUDIES AB - The analysis of interactions between human and natural systems is crucial for sound beach management practices. Those interactions can be simulated via agent-based modeling. Nevertheless, more work is needed to identify and understand model capabilities prior to societal implementations. This study presents the application of an agent-based model in the coastal town of Nags Head, NC USA. The case study focuses on the influence of storm arrival patterns and soft-engineering design alternatives on town occupation dynamics. The agent-based model consists of three interactive sub-models: (1) Natural Processes and Coastal Landforms, (2) Beach Management, and (3) Household Decisions. Modeling results indicate that sea level rise will exacerbate storm damages and could lead to a declining town population. In addition, analysis of occupancy with soft-engineering design alternatives suggests that population in Nags Head maximizes when economic benefits and protection from both, dunes and beaches, are balanced. Our results serve to exemplify the usage and capabilities of an agent-based model for beach management practices in coastal towns subjected to storms and sea level rise. Application of the model provides valuable insights of the system that can ultimately be used by decision-makers and town managers. DA - 2018/// PY - 2018/// DO - 10.1007/978-3-319-58304-4_19 VL - 24 SP - 373-395 SN - 2211-0585 KW - Human-nature interaction KW - Coastal population KW - Coupled human-physical systems KW - Community attractiveness KW - Soft-engineering KW - Storm-arrival patterns ER - TY - JOUR TI - Carbon dynamics of paper, engineered wood products and bamboo in landfills: evidence from reactor studies AU - Ximenes, Fabiano A. AU - Kathuria, Amrit AU - Barlaz, Morton A. AU - Cowie, Annette L. T2 - CARBON BALANCE AND MANAGEMENT AB - There has been growing interest in the development of waste-specific decay factors for estimation of greenhouse gas emissions from landfills in national greenhouse gas inventories. Although engineered wood products (EWPs) and paper represent a substantial component of the solid waste stream, there is limited information available on their carbon dynamics in landfills. The objective of this study was to determine the extent of carbon loss for EWPs and paper products commonly used in Australia. Experiments were conducted under laboratory conditions designed to simulate optimal anaerobic biodegradation in a landfill.Methane generation rates over incubations of 307-677 days ranged from zero for medium-density fibreboard (MDF) to 326 mL CH4 g-1 for copy paper. Carbon losses for particleboard and MDF ranged from 0.7 to 1.6%, consistent with previous estimates. Carbon loss for the exterior wall panel product (2.8%) was consistent with the expected value for blackbutt, the main wood type used in its manufacture. Carbon loss for bamboo (11.4%) was significantly higher than for EWPs. Carbon losses for the three types of copy paper tested ranged from 72.4 to 82.5%, and were significantly higher than for cardboard (27.3-43.8%). Cardboard that had been buried in landfill for 20 years had a carbon loss of 27.3%-indicating that environmental conditions in the landfill did not support complete decomposition of the available carbon. Thus carbon losses for paper products as measured in bioreactors clearly overestimate those in actual landfills. Carbon losses, as estimated by gas generation, were on average lower than those derived by mass balance. The low carbon loss for particleboard and MDF is consistent with carbon loss for Australian wood types described in previous studies. A factor for carbon loss for combined EWPs and wood in landfills in Australia of 1.3% and for paper of 48% is proposed.The new suggested combined decay factor for wood and EWPs represents a significant reduction from the current factor used in the Australian greenhouse gas inventory; whereas the suggested decay factor for paper is similar to the current decay factor. Our results improve current understanding of the carbon dynamics of harvested wood products, and allow more refined estimates of methane emissions from landfills. DA - 2018/12/27/ PY - 2018/12/27/ DO - 10.1186/s13021-018-0115-3 VL - 13 SP - SN - 1750-0680 KW - Carbon KW - Engineered wood products KW - Paper KW - Decay KW - Methane KW - Landfill KW - Greenhouse gas inventory ER - TY - JOUR TI - Fatigue and Healing Performance Assessment of Asphalt Binder from Rheological and Chemical Characteristics AU - Wang, C. AU - Xie, W. AU - Underwood, B.S. T2 - Materials and Structures DA - 2018/12// PY - 2018/12// DO - 10.1617/s11527-018-1300-2 VL - 51 IS - 6 SP - 171–182 SN - 1871-6873 KW - Asphalt binder KW - Fatigue damage KW - Healing KW - Rheology KW - Chemical composition ER - TY - JOUR TI - Seismic Fragility of Steel Piping System Based on Pipe Size, Coupling Type, and Wall Thickness AU - Ju, Bu Seog AU - Gupta, Abhinav AU - Ryu, Yonghee T2 - INTERNATIONAL JOURNAL OF STEEL STRUCTURES DA - 2018/11// PY - 2018/11// DO - 10.1007/s13296-018-0100-4 VL - 18 IS - 4 SP - 1200-1209 SN - 2093-6311 KW - T-joint KW - Threaded coupling KW - Grooved coupling KW - Pipeline ER - TY - JOUR TI - Lead-lag series and staged parallel operational strategies improve the performance and cost-effectiveness of bonechar for control of fluoride in groundwater AU - Kearns, J. AU - Krupp, A. AU - Diek, E. AU - Mitchell, S. AU - Dossi, S. AU - Hartman, S. T2 - JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT AB - Abstract Affordable, locally managed, decentralized treatment technologies are needed to protect health in resource-poor regions where communities consume groundwater containing elevated levels of fluoride (F). Bonechar is a promising low-cost sorbent for F that can be produced using local materials and simple pyrolysis technology. However, the sorption capacity of bonechar is low relative to the quantities of F that must be removed to meet health criteria (typically several mg/L), especially at pH typical of groundwaters containing high levels of geogenic F. This necessitates large bonechar contactors and/or frequent sorbent replacement, which could be prohibitively costly in materials and labor. One strategy for improving the feasibility of bonechar water treatment is to utilize lead-lag series or staged parallel configurations of two or more contactors. This study used column testing to quantify potential benefits to bonechar use rate, replacement frequency, and long-run average F concentration in treated water of lead-lag series and staged parallel operational modes compared with single contactor mode. Lead-lag series operation exhibited the largest reduction in bonechar use rate (46% reduction over single contactor mode compared with 29% reduction for staged parallel) and lowest long-run average F levels when treating central Mexican groundwater at pH 8.2 containing 8.5 mg/L F. DA - 2018/12// PY - 2018/12// DO - 10.2166/washdev.2018.111 VL - 8 IS - 4 SP - 777-784 SN - 2043-9083 KW - bonechar KW - fluoride KW - groundwater KW - household water treatment KW - Mexico KW - sorption ER - TY - JOUR TI - Controlling aerobic biological floc size using Couette-Taylor Bioreactors AU - Weaver, Joseph E. AU - Hong, Hyunsuk AU - Ducoste, Joel J. AU - de los Reyes, Francis L., III T2 - Water Research AB - Biological floc size is an important reactor microenvironment parameter that is often not experimentally controlled due to a lack of suitable methods. Here, we introduce the Couette-Taylor bioreactor (CTB) as an improved tool for controlling biological floc size, specifically as compared with bubble-column sequencing batch reactors (SBRs). A CTB consists of two concentric walls, either of which may be rotated to induce fluid motion. The induced flow produces hydrodynamic shear which is more uniform than that produced through aeration in SBRs. Because hydrodynamic shear is a major parameter controlling floc size, we hypothesized the ability to better control shear rates within a CTB would enable better-controlled floc sizes. To test this hypothesis, we measured the particle size distributions of activated sludge flocs from CTBs with either inner (iCTB) or outer (oCTB) rotating walls as well as SBRs with varying height to diameter ratios (0.5, 1.1, and 9.4). The rotation speed of the CTBs and aeration rate of the SBRs were varied to produce predicted mean shear rates from 25 to 250 s-1. Further, the shear rate distributions for each experiment were estimated using computational fluid dynamics (CFD). In all SBR experiments, the floc distributions did not significantly vary with shear rate or geometry, likely because shear rates (estimated by CFD) differed much less than originally predicted by theory. In the CTB experiments, the mean particle size decreased proportionally with increased hydrodynamic shear, and iCTBs produced particle size distributions with smaller coefficients of variation than oCTBs (0.3 vs. 0.5-0.7, respectively). DA - 2018/12// PY - 2018/12// DO - 10.1016/j.watres.2018.09.060 VL - 147 SP - 177-183 J2 - Water Research LA - en OP - SN - 0043-1354 UR - http://dx.doi.org/10.1016/j.watres.2018.09.060 DB - Crossref KW - Aerobic sludge KW - Floc size KW - Shear rate KW - Couette-taylor bioreactor ER - TY - JOUR TI - Relating soil geochemical properties to arsenic bioaccessibility through hierarchical modeling AU - Nelson, Clay M. AU - Li, Kevin AU - Obenour, Daniel R. AU - Miller, Jonathan AU - Misenheimer, John C. AU - Scheckel, Kirk AU - Betts, Aaron AU - Juhasz, Albert AU - Thomas, David J. AU - Bradham, Karen D. T2 - Journal of Toxicology and Environmental Health, Part A AB - Interest in improved understanding of relationships among soil properties and arsenic (As) bioaccessibility has motivated the use of regression models for As bioaccessibility prediction. However, limits in the numbers and types of soils included in previous studies restrict the usefulness of these models beyond the range of soil conditions evaluated, as evidenced by reduced predictive performance when applied to new data. In response, hierarchical models that consider variability in relationships among soil properties and As bioaccessibility across geographic locations and contaminant sources were developed to predict As bioaccessibility in 139 soils on both a mass fraction (mg/kg) and % basis. The hierarchical approach improved the estimation of As bioaccessibility in studied soils. In addition, the number of soil elements identified as statistically significant explanatory variables increased when compared to previous investigations. Specifically, total soil Fe, P, Ca, Co, and V were significant explanatory variables in both models, while total As, Cd, Cu, Ni, and Zn were also significant in the mass fraction model and Mg was significant in the % model. This developed hierarchical approach provides a novel tool to (1) explore relationships between soil properties and As bioaccessibility across a broad range of soil types and As contaminant sources encountered in the environment and (2) identify areas of future mechanistic research to better understand the complexity of interactions between soil properties and As bioaccessibility. DA - 2018/1/16/ PY - 2018/1/16/ DO - 10.1080/15287394.2018.1423798 VL - 81 IS - 6 SP - 160-172 J2 - Journal of Toxicology and Environmental Health, Part A LA - en OP - SN - 1528-7394 1087-2620 UR - http://dx.doi.org/10.1080/15287394.2018.1423798 DB - Crossref KW - soil KW - arsenic KW - bioaccessibility KW - hierarchical modeling KW - properties ER - TY - JOUR TI - Hierarchical modeling assessment of the influence of watershed stressors on fish and invertebrate species in Gulf of Mexico estuaries AU - Miller, Jonathan AU - Esselman, Peter C. AU - Alameddine, Ibrahim AU - Blackhart, Kristan AU - Obenour, Daniel R. T2 - Ecological Indicators AB - The northern Gulf of Mexico (GoM) spans five U.S. states and encompasses estuaries that vary greatly in size, shape, upstream river input, eutrophication status, and biotic communities. Given the variability among these estuaries, assessing their biological condition relative to anthropogenic stressors is challenging, but important to regional fisheries management and habitat conservation initiatives. Here, a hierarchical generalized linear modeling approach was developed to predict species presence in bottom trawl samples, using data from 33 estuaries over a nineteen-year study period. This is the first GoM estuary assessment to leverage Gulf-wide trawl data to develop species-level indicators and a quantitative index of estuary disturbance. After controlling for sources of variability at the sampling event, estuary, state, and sampling program levels, our approach screened for statistically significant relationships between watershed-level anthropogenic stressors and fish and invertebrate species presence. Modeling results indicate species level indicators with sensitivities to landscape stressor gradients. The most influential stressors include total anthropogenic land use, crop land use, and the number of toxic release sites in upstream watersheds, as well as agriculture in the shoreline buffer, each of which was significantly related to between 21% and 39% of the 57 species studied. Averaging the effects of these influential stressors across species, we develop a quantitative estuary stress index that can be compared against benchmark conditions. In general, disturbance levels were greatest in estuaries west of the Mississippi delta and in highly developed estuaries in southwest Florida. Estuaries from the Florida panhandle to the eastern Mississippi delta had less anthropogenic stress. DA - 2018/7// PY - 2018/7// DO - 10.1016/J.ECOLIND.2018.02.040 VL - 90 SP - 142-153 J2 - Ecological Indicators LA - en OP - SN - 1470-160X UR - http://dx.doi.org/10.1016/J.ECOLIND.2018.02.040 DB - Crossref KW - Biological assessment KW - Species indicators KW - Anthropogenic stressors KW - Hierarchical modeling KW - Watershed development KW - Gulf of Mexico ER - TY - JOUR TI - Leveraging Spatial and Temporal Variability to Probabilistically Characterize Nutrient Sources and Export Rates in a Developing Watershed AU - Strickling, H. L. AU - Obenour, D. R. T2 - Water Resources Research AB - Abstract Hybrid watershed models based on nonlinear regression are useful tools for estimating the magnitude of loading rates (i.e., export coefficients) for various pollutant sources within large‐scale river basins. Few such models, however, have incorporated temporal variability in either source distributions or climate, despite evidence that precipitation is the primary driver in interannual variability in loading rates. The model developed here includes changes in precipitation, land use, point source discharge, and livestock operations to capture temporal variability in nitrogen loads. Precipitation is incorporated directly in the formulation of export rates using coefficients that vary by source type. Instream and reservoir retention of nitrogen is included to account for nitrogen sinks within the watershed. A Bayesian hierarchical approach is employed to integrate uncertainty in loading estimates, include prior knowledge of parameters, address intrawatershed correlation, and estimate export coefficients probabilistically. We apply this method to three North Carolina river basins that have experienced substantial growth in urban development and livestock operations in the past few decades, and where eutrophication‐related water quality problems are common. Accounting for temporal variability constrains uncertainties in nonpoint source export coefficients by nearly 50%, relative to a spatial‐only model. Results indicate that livestock operations are a significant contributor of nitrogen throughout much of the study area. Precipitation is shown to have a larger influence on export rates for agricultural than for developed lands, creating a system dominated by agricultural total nitrogen during high precipitation years and by developed (urban) regions during low precipitation years. DA - 2018/7// PY - 2018/7// DO - 10.1029/2017WR022220 UR - https://doi.org/10.1029/2017WR022220 KW - hybrid watershed modeling KW - nutrients KW - nitrogen loading KW - Bayesian modeling KW - export coefficients KW - land use change ER - TY - JOUR TI - Geometry- and Appearance-Based Reasoning of Construction Progress Monitoring AU - Han, Kevin AU - Degol, Joseph AU - Golparvar-Fard, Mani T2 - Journal of Construction Engineering and Management AB - Although adherence to project schedules and budgets is most highly valued by project owners, more than 53% of typical construction projects are behind schedule and more than 66% suffer from cost overruns, partly because of an inability to accurately capture construction progress. To address these challenges, this paper presents new geometry- and appearance-based reasoning methods for detecting construction progress, which has the potential to provide more frequent progress measures using visual data that are already being collected by general contractors. The initial step of geometry-based filtering detects the state of construction of building information modeling (BIM) elements (e.g., in-progress, completed). The next step of appearance-based reasoning captures operation-level activities by recognizing different material types. Two methods have been investigated for the latter step: a texture-based reasoning for image-based 3D point clouds and color-based reasoning for laser-scanned point clouds. This paper presents two case studies for each reasoning approach to validate the proposed methods. The results demonstrate the effectiveness and practical significances of the proposed methods. DA - 2018/2// PY - 2018/2// DO - 10.1061/(ASCE)CO.1943-7862.0001428 VL - 144 IS - 2 SP - 04017110 J2 - J. Constr. Eng. Manage. LA - en OP - SN - 0733-9364 1943-7862 UR - http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0001428 DB - Crossref KW - Progress monitoring KW - Building information modeling (BIM) KW - Images KW - Point cloud KW - Laser scan KW - Three-dimensional (3D) reconstruction KW - Material classification KW - Information technologies ER - TY - CONF TI - Building an Integrated Mobile Robotic System for Real-Time Applications in Construction AU - Asadi, Khashayar AU - Ramshankar, Hariharan AU - Pullagurla, Harish AU - Bhandare, Aishwarya AU - Shanbhag, Suraj AU - Mehta, Pooja AU - Kundu, Spondon AU - Han, Kevin AU - Lobaton, Edgar AU - Wu, Tianfu AB - Building an Integrated Mobile Robotic System for Real-Time Applications in Construction Khashayar Asadi, Hariharan Ramshankar, Harish Pullagurla, Aishwarya Bhandare, Suraj Shanbhag, Pooja Mehta, Spondon Kundu, Kevin Han, Edgar Lobaton and Tianfu Wu Pages 453-461 (2018 Proceedings of the 35th ISARC, Berlin, Germany, ISBN 978-3-00-060855-1, ISSN 2413-5844) Abstract: One of the major challenges of a real-time autonomous robotic system for construction monitoring is to simultaneously localize, map, and navigate over the lifetime of the robot, with little or no human intervention. Past research on Simultaneous Localization and Mapping (SLAM) and context-awareness are two active research areas in the computer vision and robotics communities. The studies that integrate both in real-time into a single modular framework for construction monitoring still need further investigation. A monocular vision system and real-time scene understanding are computationally heavy and the major state-of-the-art algorithms are tested on high-end desktops and/or servers with a high CPU- and/or GPU- computing capabilities, which affect their mobility and deployment for real-world applications. To address these challenges and achieve automation, this paper proposes an integrated robotic computer vision system, which generates a real-world spatial map of the obstacles and traversable space present in the environment in near real-time. This is done by integrating contextual Aware- ness and visual SLAM into a ground robotics agent. This paper presents the hardware utilization and performance of the aforementioned system for three different outdoor environments, which represent the applicability of this pipeline to diverse outdoor scenes in near real-time. The entire system is also self-contained and does not require user input, which demonstrates the potential of this computer vision system for autonomous navigation. Keywords: SLAM, Context awareness, Real-time integrated system, Robotic computer vision system, Construction monitoring DOI: https://doi.org/10.22260/ISARC2018/0063 Download fulltext Download BibTex Download Endnote (RIS) TeX Import to Mendeley C2 - 2018/7/22/ C3 - Proceedings of the 35th International Symposium on Automation and Robotics in Construction (ISARC) DA - 2018/7/22/ DO - 10.22260/ISARC2018/0063 PB - International Association for Automation and Robotics in Construction (IAARC) UR - https://doi.org/10.22260/ISARC2018/0063 ER - TY - JOUR TI - Vision-based integrated mobile robotic system for real-time applications in construction AU - Asadi, Khashayar AU - Ramshankar, Hariharan AU - Pullagurla, Harish AU - Bhandare, Aishwarya AU - Shanbhag, Suraj AU - Mehta, Pooja AU - Kundu, Spondon AU - Han, Kevin AU - Lobaton, Edgar AU - Wu, Tianfu T2 - Automation in Construction AB - To increase the degree of automation and frequency of data collection for monitoring construction sites, there has been a rapid increase in the number of studies, in the past few years, that developed and/or examined mobile robotic applications in construction. These vision-based platforms capable of autonomous navigation and scene understanding are becoming essential in many construction applications, namely construction sites surveying, work-in-progress monitoring, and existing structure inspection. Simultaneous Localization and Mapping (SLAM) and object recognition for proper context-aware motion planning are some of the core vision techniques that are driving innovation for these robotic systems. To characterize the limitations of current techniques on real-time performance and identify challenges in integration and implementation for construction applications, this paper proposes a mobile robotic platform that incorporates a stack of embedded platforms with integrated Graphical Processing Units (GPUs). This paper presents three case studies to evaluate the performance of the proposed system. The results demonstrate the robustness and feasibility of developing and deploying an autonomous system in the near future. DA - 2018/12// PY - 2018/12// DO - 10.1016/j.autcon.2018.10.009 VL - 96 SP - 470-482 J2 - Automation in Construction LA - en OP - SN - 0926-5805 UR - http://dx.doi.org/10.1016/j.autcon.2018.10.009 DB - Crossref KW - Real-time integrated robotics KW - Machine vision KW - SLAM KW - Context awareness ER - TY - CONF TI - Automating Analysis of Construction Workers' Viewing Patterns for Personalized Safety Training and Management AU - Jeelani, Idris AU - Han, Kevin AU - Albert, Alex AB - Automating Analysis of Construction Workers' Viewing Patterns for Personalized Safety Training and Management Idris Jeelani, Kevin Han and Alex Albert Pages 939-947 (2018 Proceedings of the 35th ISARC, Berlin, Germany, ISBN 978-3-00-060855-1, ISSN 2413-5844) Abstract: Unrecognized hazards increase the likelihood of workplace fatalities and injuries substantially. However, recent research has demonstrated that a large proportion of hazards remain unrecognized in dynamic construction environments. Recent studies have suggested a strong correlation between viewing patterns of workers and their hazard recognition performance. Hence, it is important to study and analyze the viewing patterns of workers to gain a better understanding of their hazard recognition performance. The objective of this exploratory research is to explore hazard recognition as a visual search process to identifying various visual search factors that affect the process of hazard recognition. Further, the study also proposes a framework to develop a vision based tool capable of recording and analyzing viewing patterns of construction workers and generate feedback for personalized training and proactive safety management. Keywords: Hazard Recognition, Construction Safety, Computer vision, Eye tracking DOI: https://doi.org/10.22260/ISARC2018/0131 Download fulltext Download BibTex Download Endnote (RIS) TeX Import to Mendeley C2 - 2018/7/22/ C3 - Proceedings of the 35th International Symposium on Automation and Robotics in Construction (ISARC) DA - 2018/7/22/ DO - 10.22260/ISARC2018/0131 PB - International Association for Automation and Robotics in Construction (IAARC) UR - https://doi.org/10.22260/ISARC2018/0131 ER - TY - JOUR TI - Hybrid theorem proving as a lightweight method for verifying numerical software AU - Altuntas, Alper AU - Baugh, John T2 - PROCEEDINGS OF CORRECTNESS 2018: 2ND IEEE/ACM INTERNATIONAL WORKSHOP ON SOFTWARE CORRECTNESS FOR HPC APPLICATIONS AB - Large-scale numerical software requires substantial computer resources that complicate testing and debugging. A single run of a climate model may require many millions of core-hours and terabytes of disk space, making trial-and-error experiments burdensome and time consuming. In this study, we apply hybrid theorem proving from the field of cyber-physical systems to problems in scientific computation, and show how to verify the correctness of discrete updates that appear in the simulation of continuous physical systems. By viewing numerical software as a hybrid system that combines discrete and continuous behavior, test coverage and confidence in findings can be increased. We describe abstraction approaches for modeling numerical software and demonstrate the applicability of the approach in a case study that reproduces undesirable behavior encountered in a parameterization scheme, called the K-profile parameterization, widely used in ocean components of large-scale climate models. We then identify and model a fix in the configuration of the scheme, and verify that the undesired behavior is eliminated for all possible execution sequences. We conclude that hybrid theorem proving is an effective and efficient approach that can be used to verify and reason about properties of large-scale numerical software. DA - 2018/// PY - 2018/// DO - 10.1109/Correctness.2018.00005 SP - 1-8 KW - hybrid systems KW - formal methods KW - scientific computation KW - KeYmaera X ER - TY - JOUR TI - An Enhanced Generalized Plasticity Model for Coarse Granular Material considering Particle Breakage AU - Cen, W. J. AU - Luo, J. R. AU - Zhang, W. D. AU - Rahman, M. S. T2 - ADVANCES IN CIVIL ENGINEERING AB - In this study, an enhanced constitutive model is developed for coarse granular soil within the framework of generalized plasticity (Pastor, Zienkiewicz, and Chan, 1990). In this model, particle breakage is also considered by introducing the state parameter and the compression index into the plastic modulus, loading vectors, and plastic flow direction vectors of a generalized plasticity model. The calibration of constitutive parameters of the enhanced model is addressed in detail. The numerical simulation of triaxial tests for two types of coarse granular soils under different confining pressures is carried out to illustrate the particle breakage performance of the enhanced model. The good agreement between numerical results and experimental data indicates that the enhanced model can accurately characterize the influence of particle breakage on essential behavior of coarse granular soils. DA - 2018/// PY - 2018/// DO - 10.1155/2018/7242936 VL - 2018 SP - SN - 1687-8094 ER - TY - CONF TI - State-based formal methods in scientific computation AU - Baugh, John AU - Dyer, Tristan A2 - Butler, Michael A2 - Raschke, Alexander A2 - Hoang, Thai Son A2 - Reichl, Klaus AB - Control systems, protocols, and hardware design are among the most common applications of state-based formal methods, and yet the types of modeling and analysis they enable are also well-suited to problems in scientific computation, where quality, reproducibility, and productivity are growing concerns. We survey the challenges faced by developers of scientific software, characterize the nature of the programs they write, and offer some perspective on the role that state-based methods can play in scientific domains. C2 - 2018/// C3 - Abstract State Machines, Alloy, B, TLA, VDM, and Z CY - Cham DA - 2018/// DO - 10.1007/978-3-319-91271-4_29 SP - 392-396 PB - Springer N1 - Lecture Notes in Computer Science 10817 RN - Lecture Notes in Computer Science 10817 ER - TY - JOUR TI - Numerical study on factors influencing typhoon-induced storm surge distribution in Zhanjiang Harbor AU - Liu, Xing AU - Jiang, Wensheng AU - Yang, Bo AU - Baugh, John T2 - Estuarine, Coastal and Shelf Science AB - A 2-D unstructured finite element model is used to study how local and remote atmospheric forcing, sea level rise, and shoreline variation affect typhoon-induced storm surge in a small shallow bay, Zhanjiang Harbor (ZH). In this research, the spatial distribution of storm surge is divided into three patterns in ZH, denoted E-W, N-S, and S-N, using a quantitative method. In the Bay, local atmospheric effects (LAE) and remote atmospheric effects (RAE) both play important roles in the maximum residual water level. The contribution of RAE to the inflow is higher than that of the LAE, but the former is less important in the spatial distribution in ZH. In addition, the typhoon track influences the time of occurrence of the maximum surge by forcing the outer waters to ZH, then the spatial distribution of the surge residual in the bay is controlled by local winds, and different regions are threatened during different kinds of storm surge processes. Two sea level rise scenarios are set up in the paper as well, and the results show that the trends of the changes in LAE and RAE in the inner-bay are the opposite in the case of sea level rise; however, the total changes of the distribution are not the same in different categories. In general, the E-W category storm surge is weakened, while the N-S and S-N category storm surges have inverse changes in the north and south of ZH. There is a downward trend of the maximum surge gradient within the Bay, but relative to sea level rise itself this effect is not obvious. The establishment of the sea embankment increased the storm surge within the bay though it is not significant. DA - 2018/12// PY - 2018/12// DO - 10.1016/j.ecss.2018.09.019 VL - 215 SP - 39-51 UR - https://doi.org/10.1016/j.ecss.2018.09.019 ER - TY - JOUR TI - Space-Time Geostatistical Assessment of Hypoxia in the Northern Gulf of Mexico AU - Matli, V. Rohith Reddy AU - Fang, Shiqi AU - Guinness, Joseph AU - Rabalais, Nancy. N. AU - Craig, J. Kevin AU - Obenour, Daniel R. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Nearly every summer, a large hypoxic zone forms in the northern Gulf of Mexico. Research on the causes and consequences of hypoxia requires reliable estimates of hypoxic extent, which can vary at submonthly time scales due to hydro-meteorological variability. Here, we use an innovative space-time geostatistical model and data collected by multiple research organizations to estimate bottom-water dissolved oxygen (BWDO) concentrations and hypoxic area across summers from 1985 to 2016. We find that 27% of variability in BWDO is explained by deterministic trends with location, depth, and date, while correlated stochasticity accounts for 62% of observational variance within a range of 185 km and 28 days. Space-time modeling reduces uncertainty in estimated hypoxic area by 30% when compared to a spatial-only model, and results provide new insights into the temporal variability of hypoxia. For years with shelf-wide cruises in multiple months, hypoxia is most severe in July in 59% of years, 29% in August, and 12% in June. Also, midsummer cruise estimates of hypoxic area are only modestly correlated with summer-wide (June-August) average estimates (r2 = 0.5), suggesting midsummer cruises are not necessarily reflective of seasonal hypoxic severity. Furthermore, summer-wide estimates are more strongly correlated with nutrient loading than midsummer estimates. DA - 2018/11/6/ PY - 2018/11/6/ DO - 10.1021/acs.est.8b03474 VL - 52 IS - 21 SP - 12484-12493 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.8b03474 ER - TY - JOUR TI - Sonication-enabled rapid production of stable liquid metal nanoparticles grafted with poly(1-octadecene-alt-maleic anhydride) in aqueous solutions AU - Lin, Yiliang AU - Genzer, Jan AU - Li, Weihua AU - Qiao, Ruirui AU - Dickey, Michael D. AU - Tang, Shi-Yang T2 - NANOSCALE AB - We demonstrate sonication-enabled production of liquid metal nanoparticles grafted with poly(1-octadecene-alt-maleic anhydride) in water that remain stable in biological buffers. DA - 2018/11/14/ PY - 2018/11/14/ DO - 10.1039/c8nr05600e VL - 10 IS - 42 SP - 19871-19878 SN - 2040-3372 ER - TY - JOUR TI - Assessing the effects of water restrictions on socio-hydrologic resilience for shared groundwater systems AU - Al-Amin, Shams AU - Berglund, Emily Z. AU - Mahinthakumar, G. AU - Larson, Kelli L. T2 - Journal of Hydrology AB - Groundwater resources are shared across management boundaries. Multiple management units that differ in scale, constraints and objectives may manage a shared resource in a decentralized approach. The interactions among water managers, water users, and the water resource components influence the performance of management strategies and the resilience of community-level water supply and groundwater availability. This research develops an agent-based modeling (ABM) framework to capture the dynamic interactions among household-level consumers and policy makers to simulate water demands. The ABM is coupled with a groundwater model to evaluate effects on the groundwater table. The framework is applied to explore trade-offs between improvements in water supply sustainability for local resources and water table changes at the basin-level. A group of municipalities are simulated as agents who share access to a groundwater aquifer in Verde River Basin, Arizona. The framework provides a holistic approach to incorporate water user, municipal, and basin level objectives in evaluating water reduction strategies for long-term water resilience. DA - 2018/11// PY - 2018/11// DO - 10.1016/j.jhydrol.2018.08.045 VL - 566 SP - 872-885 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/j.jhydrol.2018.08.045 DB - Crossref KW - Agent-based model KW - Complex adaptive system KW - Groundwater management KW - Demand management KW - Water shortage KW - Sustainability index ER - TY - JOUR TI - Development of Photochemical Microsensors for Evaluating Photosynthetic Light Dose Distributions in Microalgal Photobioreactors AU - Karam, Amanda L. AU - de los Reyes, Francis L., III AU - Ducoste, Joel J. T2 - Environmental Science & Technology AB - We describe the development and testing of a Lagrangian method for quantifying light dose distributions within photobioreactors (PBRs) using novel photochemical microsensors. These microsensors were developed using 3-μm microspheres coated with a fluorescent dye that responds to wavelengths of visible light that are critical for photosynthesis. The dose–response kinetics of the microsensors was established by varying known doses of collimated light and quantifying the fluorescence responses of individual particles using flow cytometry. A deconvolution scheme was used to determine the light dose distribution from the fluorescence distribution of the microsensors. As proof-of-concept, the microsensors were used to quantify the photosynthetic light dose distributions within a gently mixed, 3 L flat-plate, batch PBR with and without algae and no gas bubbling and without algae but with gas bubbling. The microsensor approach not only provided information about the photosynthetic light distributions within the PBRs but also predicted the average light attenuation due to algal cells within 1% of estimates made with an in situ light sensor. The results showed that bubbles, under the conditions tested, increased the overall light irradiance by 18%; a result not captured by static measurements. The Lagrangian microsensors provide a novel approach for quantifying light within a photobioreactor. DA - 2018/9/27/ PY - 2018/9/27/ DO - 10.1021/acs.est.8b02056 VL - 52 IS - 21 SP - 12538-12545 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.8b02056 DB - Crossref ER - TY - JOUR TI - Fragility Assessments of Multi-Story Piping Systems within a Seismically Isolated Low-Rise Building AU - Ryu, Yonghee AU - Kwag, Shinyoung AU - Ju, Bu-Seog T2 - SUSTAINABILITY AB - A successful, advanced safety design method for building and piping structures is related to its functionality and sustainability in beyond-design-basis events such as extremely strong ground motions. This study develops analytical models of seismically isolated building-piping systems in which multi-story piping systems are installed in non-isolated and base-isolated, low-rise buildings. To achieve the sustainable design of a multi-story piping system subjected to strong ground motions, Triple Friction Pendulum (TFP) elements, specifically TFP bearings, were incorporated into the latter building structure. Then, a seismic fragility analysis was performed in consideration of the uncertainty of the seismic ground motions, and the piping fragilities for the seismically non-isolated and the base-isolated building models were quantified. Here, the failure probability of the piping system in the non-isolated building was greater than that in the seismically isolated building. The seismic isolation design of the building improved the sustainability and functionality of the piping system by significantly reducing the seismic energy of extreme ground motions which was input to the building structure itself. DA - 2018/10// PY - 2018/10// DO - 10.3390/su10103775 VL - 10 IS - 10 SP - SN - 2071-1050 KW - Triple Friction Pendulum KW - building-piping KW - seismic fragility KW - T-joint KW - base isolation ER - TY - JOUR TI - Wavefront steering of elastic shear vertical waves in solids via a composite-plate-based metasurface AU - Zhang, Jun AU - Su, Xiaoshi AU - Pennec, Yan AU - Jing, Yun AU - Liu, Xiaofeng AU - Hu, Ning T2 - JOURNAL OF APPLIED PHYSICS AB - We report a novel approach to control the wavefronts of shear vertical (SV) waves in solids using metasurfaces constituted by a stacked array of composite plates, which are composed of two connecting parts made of different materials. The metasurfaces are connected at two ends to the half-space solids where the elastic SV waves propagate. The incident SV waves in the left half-space solid induce flexural waves in the composite plates and subsequently are converted back to SV waves in the right half-space solid. The time delay of flexural waves in each composite plate of the metasurfaces is tuned through the varying length of the two connecting components. To quantitatively evaluate the time delay in each composite plate, a theoretical model for analyzing the phase of the transmitted SV waves is developed based on the Mindlin plate theory. To control the SV waves at will, each composite plate in the metasurface is delicately designed according to the proposed theoretical model. For illustrative purposes, two metasurfaces are designed and numerically validated. DA - 2018/10/28/ PY - 2018/10/28/ DO - 10.1063/1.5049515 VL - 124 IS - 16 SP - SN - 1089-7550 ER - TY - JOUR TI - Geotechnical design parameter evaluation using the alluvial plain characteristics in southeastern Iraq AU - Do, Jinung AU - Heo, Ong AU - Yoon, Yeo-Won AU - Chang, Ilhan T2 - ARABIAN JOURNAL OF GEOSCIENCES DA - 2018/10// PY - 2018/10// DO - 10.1007/s12517-018-4019-z VL - 11 IS - 20 SP - SN - 1866-7538 KW - Alluvial plain KW - Arid regions KW - Geotechnical design parameters KW - In situ test KW - Laboratory test KW - Southeastern Iraq ER - TY - JOUR TI - EMERGENCY RESPONSE DURING DISASTROUS SITUATION IN DENSELY POPULATED URBAN AREAS: A GIS BASED APPROACH AU - Hasnat, Md Mehedi AU - Islam, Md Rakibul AU - Hadiuzzaman, Md T2 - GEOGRAPHIA TECHNICA DA - 2018/10// PY - 2018/10// DO - 10.21163/GT_2018.132.06 VL - 13 IS - 2 SP - 74-88 SN - 2065-4421 KW - Disaster response KW - Spatial analysis KW - Emergency management KW - Network analysis KW - ArcGIS ER - TY - JOUR TI - CFRP shear strengthening system for steel bridge girders AU - Kazem, Hamid AU - Zhang, Ye AU - Rizkalla, Sami AU - Seracino, Rudolf AU - Kobayashi, Akira T2 - ENGINEERING STRUCTURES AB - This paper presents an investigation undertaken to study the effectiveness of using small-diameter CFRP strands for shear strengthening of steel bridge girders. The study includes a comprehensive experimental program to study effects of the CFRP reinforcement ratio and orientation of the strands. An analytical model, calibrated by the experimental tests, was used to provide design recommendation. Results of the study showed that the proposed strengthening system is effective in increasing the shear capacity of steel bridge girders and there was no sign of CFRP debonding or rupture failure commonly observed by CFRP laminates up to approximately 80% of the steel yield stress. DA - 2018/11/15/ PY - 2018/11/15/ DO - 10.1016/j.engstruct.2018.08.038 VL - 175 SP - 415-424 SN - 1873-7323 KW - Small-diameter CFRP KW - Steel Girder KW - Shear KW - Strengthening ER - TY - JOUR TI - Amending anaerobic bioreactors with pyrogenic carbonaceous materials: the influence of material properties on methane generation AU - Cheng, Qiwen AU - de los Reyes, Francis L. AU - Call, Douglas F. T2 - Environmental Science: Water Research & Technology AB - The impact of pyrogenic carbonaceous material amendments on methane production in short-term anaerobic batch reactors depended on multiple material properties, including, but not limited to, electrical conductivity. DA - 2018/// PY - 2018/// DO - 10.1039/c8ew00447a VL - 4 IS - 11 SP - 1794-1806 J2 - Environ. Sci.: Water Res. Technol. LA - en OP - SN - 2053-1400 2053-1419 UR - http://dx.doi.org/10.1039/c8ew00447a DB - Crossref ER - TY - JOUR TI - Size distribution of vehicle emitted primary particles measured in a traffic tunnel AU - Li, Xiang AU - Dallmann, Timothy R. AU - May, Andrew A. AU - Stanier, Charles O. AU - Grieshop, Andrew P. AU - Lipsky, Eric M. AU - Robinson, Allen L. AU - Presto, Albert A. T2 - ATMOSPHERIC ENVIRONMENT AB - Total and size-resolved concentrations and emission factors are used to compare fleet-averaged vehicle emissions in Pittsburgh, PA in 2002 and 2014. Winter-time traffic tunnel measurements acquired using dual scanning mobility particle sizers (SMPS) over the size range 3–500 nm form the key input for the analysis. Size-resolved mass emission factors were calculated assuming a nanoparticle aggregate model. The ultrafine particle (<30 nm) emissions of diesel vehicles significantly dropped from 2002 to 2014. In the 2014 study, a thermodenuder (TD) was deployed together with the SMPS to measure emissions of non-volatile particles. After evaporation at 250 °C inside the TD, the median diameter of the number-size distribution shifted from 16 nm to ∼7 nm. The total particle number decreased significantly (69%) after evaporating inside the TD, indicating that vehicle emitted particles may be largely externally mixed and that a large fraction of these particles may be purely composed of volatile components. Based on the SMPS-TD measurements, we report a size-resolved volatile-to-non-volatile-component-ratio for vehicle emitted particles. It shows that smaller particles (10–60 nm) emitted by vehicles are dominantly (over 75%) composed of volatile components. We also apportioned the size-resolved particles and non-volatile particle mass and number emission factors for both gasoline and diesel vehicles. Diesel vehicles emitted significantly more ultrafine particles and non-volatile particles than gasoline vehicles. DA - 2018/10// PY - 2018/10// DO - 10.1016/j.atmosenv.2018.07.052 VL - 191 SP - 9-18 SN - 1873-2844 KW - Emissions KW - Diesel KW - Size distribution KW - Aerosol ER - TY - JOUR TI - Boundary Elements of Special Reinforced Concrete Walls Tested under Different Loading Paths AU - Haro, Ana G. AU - Kowalsky, Mervyn AU - Chai, Y. H. AU - Lucier, Gregory T2 - EARTHQUAKE SPECTRA AB - Large inelastic tensile strains and wide horizontal cracks primarily caused by in-plane loading, may lead to local out-of-plane deformations of the end regions of reinforced concrete (RC) walls within a buckled zone that comprises the plastic hinge length. Critical parameters that influence the onset of this failure mode have been studied through past experimental tests on RC prisms subjected to axial loading, which simulates the response of end regions of RC walls under in-plane demands. Missing from those studies is the effect of bidirectional loading protocols and the effect of the longitudinal reinforcement ratio on the hysteretic response. Therefore, 12 RC prisms with 3 longitudinal steel ratios representative of prototype boundary elements of typical special RC walls and piers walls were tested. The experimental results showed that the longitudinal steel content and the in-plane loading demands mainly govern the onset of out-of-plane buckling instability of planar RC walls. DA - 2018/// PY - 2018/// DO - 10.1193/081617EQS160M VL - 34 IS - 3 SP - 1267–1288 ER - TY - JOUR TI - Finite deformation analysis of slip-induced crystalline rotations during tensile and compressive tests on bcc iron crystals AU - Havner, Kerry S. AU - Franciosi, Patrick T2 - PHILOSOPHICAL MAGAZINE AB - This work compares slip-induced lattice rotations calculated from double-slip, finite-deformation analytical solutions to electron-back-scattering-diffraction (EBSD) rotation measurements from SEM in situ, room temperature straining of bcc iron crystals. The finite-deformation modelling assumes slip proportionality between the two dominant active systems. Four experimental cases from a recently published work (2015) are examined, two in axial tension and two in axial compression. They correspond to mixed double-slip on {110} and {112} planes, with slip on the latter in both ‘easy’ and ‘hard’ orientations. In the experiments, EBSD rotation measurements were made on three faces of the iron samples and the dominant active systems were identified from slip traces. Here the relative contributions of the two systems for the best match with available rotation data are determined for each case, and the results discussed in relation to initial shear stress and (probable) critical shear-strength ratios. The analyses provide insight into achievable accuracy in crystal-slip quantification, based on slip-trace observations and rotation measurements of a sample’s load and lateral axes, and some assessment of the relative hardening of active slip systems. DA - 2018/11/2/ PY - 2018/11/2/ DO - 10.1080/14786435.2018.1506177 VL - 98 IS - 31 SP - 2797-2825 SN - 1478-6443 KW - Bcc iron crystals KW - slip kinematics KW - proportional double-slip KW - finite deformation experiments ER - TY - JOUR TI - Closure to "Comparison of Three Retaining Wall Condition Assessment Rating Systems" by Mohammed A. Gabr, William Rasdorf, Daniel J. Findley, Cedrick J. Butler, and Steven A. Bert AU - Gabr, Mohammed A. AU - Rasdorf, William AU - Findley, Daniel J. AU - Butler, Cedrick J. AU - Bert, Steven A. T2 - JOURNAL OF INFRASTRUCTURE SYSTEMS DA - 2018/12// PY - 2018/12// DO - 10.1061/(ASCE)IS.1943-555X.0000447 VL - 24 IS - 4 SP - SN - 1943-555X ER - TY - JOUR TI - Simulation of Work Zones with Lane Closures in Proximity of Freeway Interchanges AU - Yeom, Chunho AU - Rasdorf, William AU - Rouphail, Nagui AU - Schroeder, Bastian T2 - IEEE INTELLIGENT TRANSPORTATION SYSTEMS MAGAZINE AB - The paper provides methodologies for microscopic simulation modelling of freeway work zones with lane closures in the proximity of interchanges. In addition, the research presents simulation results using calibrated modelling parameters to determine the capacity available for mainline flow under various operating conditions. The results will help researchers or practitioners with designing and studying freeway work zone sites under various lane configurations using better estimates of delays and queue sizes in the proximity of interchanges. Additionally, a 2 to 1 on-ramp merge condition was explored to predict the merge ratios under both demand and service flow conditions. The paper illustrates how ramp demand affects the share of segment capacity available to mainline traffic to reveal strategies for controlling this demand (via ramp metering for example) in order to maintain a prescribed freeway capacity through the work zone. The overall study result indicates the degree to which the presence of a work zone with lane closures decreases the proportion of mainline flow and shows the degree to which differences in work zone lane configurations affect merge and weave scenarios. DA - 2018/// PY - 2018/// DO - 10.1109/MITS.2018.2842027 VL - 10 IS - 3 SP - 184-195 SN - 1941-1197 ER - TY - JOUR TI - Real-Time Prediction of Seasonal Heteroscedasticity in Vehicular Traffic Flow Series AU - Huang, Wei AU - Jia, Wenwen AU - Guo, Jianhua AU - Williams, Billy AU - Shi, Guogang AU - Wei, Yun AU - Cao, Jinde T2 - IEEE Transactions on Intelligent Transportation Systems AB - Over the past decade, traffic heteroscedasticity has been investigated with the primary purpose of generating prediction intervals around point forecasts constructed usually by short-term traffic condition level forecasting models. However, despite considerable advancements, complete traffic patterns, in particular the seasonal effect, have not been adequately handled. Recently, an offline seasonal adjustment factor plus GARCH model was proposed in Shi et al. 2014 to model the seasonal heteroscedasticity in traffic flow series. However, this offline model cannot meet the real-time processing requirement proposed by real-world transportation management and control applications. Therefore, an online seasonal adjustment factors plus adaptive Kalman filter (OSAF+AKF) approach is proposed in this paper to predict in real time the seasonal heteroscedasticity in traffic flow series. In this approach, OSAF and AKF are combined within a cascading framework, and four types of online seasonal adjustment factors are developed considering the seasonal patterns in traffic flow series. Empirical results using real-world station-by-station traffic flow series showed that the proposed approach can generate workable prediction intervals in real time, indicating the acceptability of the proposed approach. In addition, compared with the offline model, the proposed online approach showed improved adaptability when traffic is highly volatile. These findings are important for developing real-time intelligent transportation system applications. DA - 2018/// PY - 2018/// DO - 10.1109/TITS.2017.2774289 VL - 19 IS - 10 SP - 3170–3180 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85038392558&partnerID=MN8TOARS ER - TY - JOUR TI - Real-Time Energy Audit of Built Environments: Simultaneous Localization and Thermal Mapping AU - Ramachandra, Bharathkumar AU - Nawathe, Pranav AU - Monroe, Jacob AU - Han, Kevin AU - Ham, Youngjib AU - Vatsavai, Ranga Raju T2 - JOURNAL OF INFRASTRUCTURE SYSTEMS AB - Leveraging thermography for managing built environments has become prevalent as a robust tool for detecting, analyzing, and reporting their performance in a nondestructive manner. Despite many documented benefits of thermographic inspection for better characterizing the conditions of built environments, current thermographic inspections still have several inefficiencies. Inspectors typically collect and store large numbers of thermal images or long-sequence thermal videos to support decision making on the maintenance and rehabilitation of built environments. However, more importantly, these large-scale visual data are typically unordered and not localized (a term used to define a process of finding locations or relative positions of a camera). This paper proposes and compares two approaches for simultaneous localization and thermal mapping. These methods estimate a camera’s pose and map the environment in three dimensions in real-time. Case studies using an off-the-shelf hardware configuration using solely thermal cameras and an author-customized configuration using both thermal and red, green, and blue (RGB) cameras are conducted and the results are compared with a well-established offline three-dimensional mapping tool. The results show that combining information from RGB and thermal cameras provides significant benefits to real-time localization compared with using solely thermal cameras and that the proposed real-time methods have localization performance comparable to the offline tool. DA - 2018/9// PY - 2018/9// DO - 10.1061/(ASCE)IS.1943-555X.0000431 VL - 24 IS - 3 SP - SN - 1943-555X ER - TY - JOUR TI - Experimental investigations on the boiling heat transfer of horizontal flow in the near-critical region AU - Lei, Xianliang AU - Zhang, Weiqiang AU - Zhang, Jun AU - Dinh, Nam AU - Li, Huixiong T2 - INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER AB - The critical point is the end point of a phase equilibrium curve; liquid and its vapor can coexist under designated points. Close to the critical point, thermophysical properties present clear variations, especially in the region of 0.85Pcr∼Pcr. Latent heat and liquid density in this region decrease more quickly than in lower-pressure areas, resulting in unique boiling heat transfer behavior. This region is also called the near-critical region. However, only a few scholars have discussed the heat transfer phenomenon; thus, it is difficult to ascertain the near-critical region’s properties and characteristics from extant literature. In the present study, we conduct experimental investigations to explore the specificities of the heat transfer characteristics of carbon dioxide in horizontal flow within the near-critical region in a circular channel with a diameter of 4 mm. The operating pressure ranges from 6.26 MPa to 7.3 MPa with a mass flow rate between 200 and 400 kg/m2 s, heat flux between 5 and 140 kW/m2, and test section inlet temperature of −5 °C. Then, we examine the inner-wall temperature and heat transfer coefficient profiles at different pressures within the near-critical region. The results show that at high heat flux, departure from nucleate boiling (DNB) phenomenon presents with a sudden decrease in the heat transfer coefficient in the subcooled region. The higher the heat flux, the more seriously deteriorating the heat transfer is. Interestingly, the temperature reaches its peak in the post-DNB region rather than at the critical vapor quality point. With an increase in pressure, DNB occurs early with lower vapor quality, and the temperature peak decreases at the given heat flux and mass flux. On the contrary, DNB is delayed with an increase in mass flux. A series of boiling heat transfer correlations in a subcooled region, two-phase flow region, and superheated region are proposed in addition to a new predictive correlation for critical heat flux in the near-critical region at a given mass flux. DA - 2018/10// PY - 2018/10// DO - 10.1016/j.ijheatmasstransfer.2018.04.043 VL - 125 SP - 618-628 SN - 1879-2189 KW - Carbon dioxide KW - Critical region KW - DNB KW - Heat transfer correlation KW - Heat transfer coefficient KW - Critical heat flux ER - TY - JOUR TI - State-of-the-art review and future research directions for FRP-to-masonry bond research: Test methods and techniques for extraction of bond-slip behaviour AU - Vaculik, J. AU - Visintin, P. AU - Burton, N. G. AU - Griffith, M. C. AU - Seracino, R. T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The effectiveness of FRP retrofits is heavily reliant on the shear bond that can be developed between the FRP and masonry substrate, which has been the focus of experimental research for almost two decades. This paper collates and critically reviews previous experimental work on the shear bond between FRP composites and masonry substrates, identifying 1583 individual pull-tests across 56 published studies. Whilst the pool of existing data is significant in terms of number of tests, it encompasses a rather narrow range of substrate material, FRP material and retrofit configuration. Most notably, the majority of tests have been undertaken on clay brick substrates, carbon FRPs and externally-bonded retrofits. By contrast, testing of natural stone substrates and near-surface-mounted retrofits has been limited. Significantly, the review identifies considerable inconsistency in the test arrangements, instrumentation methods, and data processing techniques for extracting local bond-slip properties, which has undoubtedly hindered the development of a unified bond model and codifiable design rules. Methods of extracting bond-slip behaviour from test data are critically reviewed, and importantly it is shown through numerical examples that without adequate instrumentation it is not possible to reliably extract this behaviour from standard pull-tests. Finally, suggestions for adequate instrumentation and a framework for undertaking bond-slip behaviour extraction through inverse analysis are presented. Significantly, the experimental database compiled as part of this work-thought to be the largest of its kind to date—is made openly available as an accompanying Data in Brief article with the intent that it will facilitate development of bond-strength models for FRP bonded to masonry. DA - 2018/9/20/ PY - 2018/9/20/ DO - 10.1016/j.conbuildmat.2018.06.103 VL - 183 SP - 325-345 SN - 1879-0526 KW - Unreinforced masonry (URM) KW - Clay brick KW - Natural stone KW - Retrofit KW - Fibre-reinforced polymer (FRP) KW - Bond-slip KW - Load-slip KW - Bond-strength ER - TY - JOUR TI - A non-parametric bootstrapping framework embedded in a toolkit for assessing water quality model performance AU - Libera, Dominic A. AU - Sankarasubramanian, A. AU - Sharma, Ashish AU - Reich, Brian J. T2 - Environmental Modelling & Software AB - Assessing the ability to predict nutrient concentration in streams is important for determining compliance with the Numeric Nutrient Water Quality Criteria for Nitrogen in the U.S.A. Evaluation of the USGS's Load Estimator (LOADEST) and the Weighted Regression on Time, Discharge, and Season (WRTDS) models in predicting total nitrogen loads over 18 stations from the Water Quality Network show good performance (Nash-Sutcliffe Efficiency (NSE) > 0.8) in capturing the observed variability even for stations with limited data. However, both models captured only 40% of observed variance in total nitrogen (TN) concentration (NSE < 0.4). Thus, the same dataset performed differently in predicting two attributes – TN load and concentration – questioning the predictive skill of the models. This study proposes a non-parametric re-sampling approach for assessing the performance of water quality models particularly in predicting TN concentration. Null distributions for three common performance metrics belonging to populations of metrics with no skill in capturing the observed variability are constructed through a bootstrap resampling technique. Sample metrics from the LOADEST and WRTDS model in predicting TN concentration are used to calculate p-values for determining if the sample metrics belongs to the null distributions. . DA - 2018/9// PY - 2018/9// DO - 10.1016/j.envsoft.2018.05.013 VL - 107 SP - 25-33 J2 - Environmental Modelling & Software LA - en OP - SN - 1364-8152 UR - http://dx.doi.org/10.1016/j.envsoft.2018.05.013 DB - Crossref KW - Water quality modeling KW - Performance assessment KW - Non-parametric re-sampling ER - TY - JOUR TI - What is the role of water in the geopolymerization of metakaolin? AU - Park, Sungwoo AU - Pour-Ghaz, Mohammad T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Despite the significant advances in understanding the structure of geopolymers in the last decades, the role of water in the geopolymerization of aluminosilicates and within the structure of geopolymers remains elusive. The present paper investigates the role of water in the geopolymerization of metakaolin, a low calcium aluminosilicate. We differentiate between different states of water in these materials and discuss the nature and the origin of non-evaporable (chemically bound) water, and evaporable water. We propose a conceptual model for the microstructure of metakaolin based geopolymers that accounts for different states of water within their structure and discuss the implications of their composition on pore size distribution. DA - 2018/9/10/ PY - 2018/9/10/ DO - 10.1016/j.conbuildmat.2018.06.073 VL - 182 SP - 360-370 SN - 1879-0526 KW - Evaporable water KW - Geopolymer KW - Metakaolin KW - Non-evaporable water KW - Pore size distribution KW - NASH KW - NAS ER - TY - JOUR TI - Automating and scaling personalized safety training using eye-tracking data AU - Jeelani, Idris AU - Han, Kevin AU - Albert, Alex T2 - Automation in Construction AB - Research has shown that a large proportion of hazards remain unrecognized, which expose construction workers to unanticipated safety risks. Recent studies have also found that a strong correlation exists between viewing patterns of workers, captured using eye-tracking devices, and their hazard recognition performance. Therefore, it is important to analyze the viewing patterns of workers to gain a better understanding of their hazard recognition performance. From the training standpoint, scan paths and attention maps, generated using eye-tracking technology, can be used effectively to provide personalized and focused feedback to workers. Such feedback is used to communicate the search process deficiency to workers in order to trigger self-reflection and subsequently improve their hazard recognition performance. This paper proposes a computer vision-based method that tracks workers on a construction site and automatically locates their fixation points, collected using a wearable eye-tracker, on a 3D point cloud. This data is then used to analyze their viewing behavior and compute their attention distribution. The presented case studies validate the proposed method. DA - 2018/9// PY - 2018/9// DO - 10.1016/j.autcon.2018.05.006 VL - 93 SP - 63-77 J2 - Automation in Construction LA - en OP - SN - 0926-5805 UR - http://dx.doi.org/10.1016/j.autcon.2018.05.006 DB - Crossref KW - Hazard recognition KW - Construction safety KW - 3D-reconstruction KW - Eye-tracking KW - Computer vision KW - Personalized training ER - TY - JOUR TI - Trends in on-road transportation, energy, and emissions AU - Altshuler, Samuel L. AU - Ayala, Alberto AU - Collet, Susan AU - Chow, Judith C. AU - Frey, H. Christopher AU - Shaikh, Rashid AU - Stevenson, Eric D. AU - Walsh, Michael P. AU - Watson, John G. T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION DA - 2018/// PY - 2018/// DO - 10.1080/10962247.2018.1512734 VL - 68 IS - 10 SP - 1015-1024 SN - 2162-2906 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85054087647&partnerID=MN8TOARS ER - TY - JOUR TI - Metrics That Matter: Core Predictive and Diagnostic Metrics for Improved Project Controls and Analytics AU - Orgut, Resulali Emre AU - Zhu, Jin AU - Batouli, Mostafa AU - Mostafavi, Ali AU - Jaselskis, Edward J. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Project progress and performance assessment is critically important to the successful delivery of capital facility projects. However, there is no standardized approach for the selection and use of project control metrics, making it difficult to analyze project progress and performance for transforming data into meaningful insights. This research identified core predictive and diagnostic metrics that may provide actionable insights into a project’s actual progress, performance, and forecast at completion. The methodology used for identifying these metrics included a literature review, surveys, expert evaluation utilizing the Delphi method, and statistical validation. The researchers analyzed 44 surveys and collected multiple rounds of responses from 16 subject matter experts to validate the findings. Results indicated there are 20 core metrics, seven validation metrics, seven innovative metrics, and 14 other significant metrics, which can be used for multiple project types, sizes, and contracting strategies. Statistical analyses of the survey data were used to further validate the core metrics and demonstrated that use of more core metrics corresponded with project cost performance and using more diagnostic metrics in projects led to better schedule performance. DA - 2018/11// PY - 2018/11// DO - 10.1061/(ASCE)CO.1943-7862.0001538 VL - 144 IS - 11 SP - SN - 1943-7862 KW - Project control metrics KW - Cost and schedule KW - Performance assessment KW - Forecasting ER - TY - JOUR TI - Use-Phase Drives Lithium-Ion Battery Life Cycle Environmental Impacts When Used for Frequency Regulation AU - Ryan, Nicole A. AU - Lin, Yashen AU - Mitchell-Ward, Noah AU - Mathieu, Johanna L. AU - Johnson, Jeremiah X. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Battery storage systems are attractive alternatives to conventional generators for frequency regulation due to their fast response time, high cycle efficiency, flexible scale, and decreasing cost. However, their implementation does not consistently reduce environmental impacts. To assess these impacts, we employed a life cycle assessment (LCA) framework. Our framework couples cradle-to-gate and end-of-life LCA data on lithium-ion batteries with a unit commitment and dispatch model. The model is run on a 9-bus power system with energy storage used for frequency regulation. The addition of energy storage changes generator commitment and dispatch, causing changes in the quantities of each fuel type consumed. This results in increased environmental impacts in most scenarios. The impacts caused by the changes in the power system operation (i.e., use-phase impacts) outweigh upstream and end-of-life impacts in the majority of scenarios analyzed with the magnitude most influenced by electricity mix and fuel price. Of parameters specific to the battery, round trip efficiency has the greatest effect. DA - 2018/9/4/ PY - 2018/9/4/ DO - 10.1021/acs.est.8b02171 VL - 52 IS - 17 SP - 10163-10174 SN - 1520-5851 ER - TY - JOUR TI - Cooperative game theory and last addition method in the allocation of firm energy rights AU - Faria, Victor. A. D. AU - Queiroz, Anderson Rodrigo AU - Lima, Luana M. M. AU - Lima, Jose W. M. T2 - APPLIED ENERGY AB - The firm energy rights of a hydro plant is a parameter used in some electricity markets to define the maximum amount of energy that a power plant can trade through contracts. In a centralized dispatch scheme, the coordinated operation of the hydro plants generates a synergetic gain in the system firm energy, in this setting, a question that often arises is how to fairly allocate this energy among each hydro plant. This work proposes a formulation to compute the firm energy rights of hydro plants using cooperative game theory and the last addition allocation method. The main goal is to integrate the interests of hydro agents with the needs of the regulatory agencies, searching in the core of the game for solutions that give the right incentives to the optimal system development. In order to make simulations of real instances possible, it is proposed a reformulation of the traditional mixed integer linear programming model that computes the core constraints, which induces a significant speed-up of the algorithm solution time. It is shown an application of the proposed methodology to a real instance representing the Brazilian electric power system. DA - 2018/9/15/ PY - 2018/9/15/ DO - 10.1016/j.apenergy.2018.06.065 VL - 226 SP - 905-915 SN - 1872-9118 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85048638261&partnerID=MN8TOARS KW - Cooperative game theory KW - Mixed integer linear programming KW - Firm energy rights KW - Electric power systems KW - Hydro power KW - Benders decomposition ER - TY - JOUR TI - Detection and reconstruction of complex structural cracking patterns with electrical imaging AU - Smyl, Danny AU - Pour-Ghaz, Mohammad AU - Seppanen, Aku T2 - NDT & E INTERNATIONAL AB - The ability to detect cracks in structural elements is an integral component in the assessment of structural heath and integrity. Recently, Electrical Resistance Tomography (ERT) -based sensing skins have been shown to reliably image progressive surface damage on structural members. However, so far the approach has only been tested in cases of relatively simple crack patterns. Because the spatial resolution of ERT is generally low, it is an open question whether the ERT-based sensing skins are able to image complex structural cracking patterns. In this paper, we test the accuracy of ERT for reconstructing cracking patterns experimentally and computationally. In the computational study, we use a set of numerical simulations that model progressive cracking in a rectangular beam geometry. We also investigate the effect of image reconstruction methods on the crack pattern estimates: In addition to the contemporary image reconstruction method used in the recent sensing skin studies, we test the feasibility of a novel approach where model-based structural prior information on the cracking probability is accounted for in the image reconstruction. The results of this study indicate that ERT-based sensing skins are able to detect and reconstruct complex structural cracking patterns, especially when structural prior information is utilized in the image reconstruction. DA - 2018/10// PY - 2018/10// DO - 10.1016/j.ndteint.2018.06.004 VL - 99 SP - 123-133 SN - 1879-1174 KW - Damage detection KW - Finite element analysis KW - Image analysis KW - Inverse problem ER - TY - JOUR TI - Managing active cultural differences in US construction workplaces: Perspectives from non-Hispanic workers AU - Al-Bayati, Ahmed Jalil AU - Abudayyeh, Osama AU - Albert, Alex T2 - JOURNAL OF SAFETY RESEARCH AB - Current census reports indicate a growing shift toward workforce diversity in the U.S. construction industry, which is largely the result of increasing participation from the Hispanic community. The data also suggest that the Hispanic workforce suffers a higher rate of fatal injuries compared to their non-Hispanic counterparts. Therefore, there is a dire need to develop and utilize new management tools and strategies to accommodate the differences in language and culture of this incoming labor force.The absence of these tools and strategies poses several challenges including cost overrun, schedule delay, and more importantly, higher workplace injury rates. This study aims to provide a better understanding of the contribution of cultural diversity as a factor that may influence the overall site safety.As a result, this study provides further evidence that indicate that the current findings regarding the influence of active cultural differences are reliable, valid, and needs attention. Furthermore, the study provides sub-analysis results of cultural values among Hispanic workers, which suggest that workers from Mexico are less likely to speak up on safety issues when compared to other Hispanic workers. Therefore, this study has both practical and theoretical implications for managing workforce diversity and related safety performance in the U.S. construction industry. The results of the study can be used by employers and managers to adopt responsive strategies and tools to reduce the likelihood of fatal and nonfatal injuries among Hispanic workers. DA - 2018/9// PY - 2018/9// DO - 10.1016/j.jsr.2018.05.004 VL - 66 SP - 1-8 SN - 1879-1247 KW - Hispanic Workforce KW - The Construction Industry KW - Active Cultural Differences KW - Hofstede Theory KW - Safety Management ER - TY - JOUR TI - Dynamic analysis of a planar multi-stage centrifugal pump rotor system based on a novel coupled model AU - Zhou, Wenjie AU - Qiu, Ning AU - Wang, Leqin AU - Gao, Bo AU - Liu, Dong T2 - JOURNAL OF SOUND AND VIBRATION AB - The coupled rotor-dynamics issue is always one of the most important and difficult research for multi-stage pump system due to the complexity of multiple fluid-induced forces and multi-degree of freedom rotor model. In this paper, the Reynolds equation of journal bearing is solved by the finite difference method and corresponding fluid-induced force is obtained by small parameter method. In addition, the dynamic coefficients of annular seal are calculated according to bulk-flow model and perturbation method. Furthermore, a novel rotor system model fully considering the coupled effects of bearing and seal is proposed by matrix manipulation method. Then the coupled rotor-dynamics for multi-stage pump system is investigated subsequently based on the novel model. Finally, the Lomakin effect of annular seal is studied in detail. The calculated results indicate that the fluid-induced force of seal exerting on the rotor system should not be ignored in the calculation of coupled dynamic characteristics. Smaller length and clearance of annular seal are good for the stability of coupled rotor system. Compared with asymmetric structure, the symmetric sealing structure has a larger stability margin on condition of ‘rigid rotor’ status. Moreover, the Lomakin effect on stability presents linear superposition property. The proposed method can provide valuable reference for the design and modeling of multi-dimensional matrix system. DA - 2018/11/10/ PY - 2018/11/10/ DO - 10.1016/j.jsv.2018.07.041 VL - 434 SP - 237-260 SN - 1095-8568 KW - Coupled rotor system KW - Multi-degree of freedom (M-DoF) KW - Matrix manipulation method (MMM) KW - Dynamic characteristics KW - Lomakin effect ER - TY - JOUR TI - Quantifying prestressing force loss due to corrosion from dynamic structural response AU - Rashetnia, Reza AU - Ghasemzadeh, Farnam AU - Hallaji, Milad AU - Pour-Ghaz, Mohammad T2 - JOURNAL OF SOUND AND VIBRATION AB - In prestressed concrete structures, corrosion of prestressing strands is a major durability concern. In advanced stages, corrosion may result in the rupture of strands. At early stages, corrosion of strands results in microcracking, deterioration of bond between strands and concrete, and therefore, in the loss of prestressing force. These effects, in turn, result in the change of dynamic response of prestressed elements. In this paper, we investigate whether the prestressing force of prestressed beams can be estimated indirectly using dynamic vibration test. For this purpose, six prestressed concrete beams were manufactured. Two beams were kept as control, two beams were corroded along the entire length of the strand, and two beams were corroded along one-third of the strand length. The induced accelerated corrosion was monitored by corrosion current measurements and passive acoustic emission. Two system identification approaches were developed where both utilize the free vibration response of an Euler-Bernoulli beam to estimate prestressing force of strands. Due to the ill-possedness of the identification problems and the presence of random and systematic errors in the experiment, Tikhonov regularization method was used. Finally, results were compared with analytical solution of vibration of a simply supported beam with external compressive force. It was concluded that using dynamic vibration of prestressed concrete beams and using indirect estimation approaches, it is possible to quantify the loss of prestressing force due to corrosion. DA - 2018/10/27/ PY - 2018/10/27/ DO - 10.1016/j.jsv.2018.07.012 VL - 433 SP - 129-137 SN - 1095-8568 KW - Acoustics KW - Corrosion KW - Dynamic vibration KW - Inverse problem KW - Prestressed concrete beam KW - Regularization ER - TY - JOUR TI - Seismic Performance of a Fire-Exposed Moment-Resisting Frame AU - Quayyum, Shahriar AU - Hassan, Tasnim T2 - JOURNAL OF STRUCTURAL ENGINEERING AB - Major earthquakes in urban areas often lead to building fires. Such earthquakes frequently damage buildings’ water sprinkler systems and diminish or strain firefighting capabilities. In such scenarios, buildings get exposed to fire for a long period of time, resulting in damage of spray-on-fire resistive materials. Consequently, steel frame temperature may reach as high as the maximum fire temperature, which subsequently cools slowly to ambient temperature. If the building frame does not deform severely after such a fire event, it is usually rehabilitated for continued occupation. The performance of such a fire-exposed steel building during a future earthquake is not known. This study investigates the seismic performance of a fire-exposed steel frame by performing finite-element analyses incorporating fire-exposed steel material properties. The simulation responses demonstrate vulnerability of fire-exposed steel buildings. A novel but startling observation made is that under seismic loading, a fire-damaged steel frame may form a soft-story mechanism at the story of fire exposure because of plastic hinge formation in the column instead of in the beams. DA - 2018/11// PY - 2018/11// DO - 10.1061/(ASCE)ST.1943-541X.0002201 VL - 144 IS - 11 SP - SN - 1943-541X KW - Fire-exposed building KW - Fire-induced heterogeneity KW - Fire-induced strength reduction KW - Seismic response KW - Soft-story mechanism ER - TY - JOUR TI - US Energy-Related Greenhouse Gas Emissions in the Absence of Federal Climate Policy AU - Eshraghi, Hadi AU - Queiroz, Anderson Rodrigo AU - DeCarolis, Joseph F. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - The planned US withdrawal from the Paris Agreement as well as uncertainty about federal climate policy has raised questions about the country’s future emissions trajectory. Our model-based analysis accounts for uncertainty in fuel prices and energy technology capital costs and suggests that market forces are likely to keep US energy-related greenhouse gas emissions relatively flat or produce modest reductions: in the absence of new federal policy, 2040 greenhouse gas emissions range from +10% to −23% of the baseline estimate. Natural gas versus coal utilization in the electric sector represents a key trade-off, particularly under conservative assumptions about future technology innovation. The lowest emissions scenarios are produced when the cost of natural gas and electric vehicles declines, while coal and oil prices increase relative to the baseline. DA - 2018/9/4/ PY - 2018/9/4/ DO - 10.1021/acs.est.8b01586 VL - 52 IS - 17 SP - 9595-9604 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85052916806&partnerID=MN8TOARS ER - TY - JOUR TI - Data-driven approach for identifying spatiotemporally recurrent bottlenecks AU - Song, Tai-Jin AU - Williams, Billy M. AU - Rouphail, Nagui M. T2 - IET INTELLIGENT TRANSPORT SYSTEMS AB - Identification of recurrent bottlenecks is an effective way to hone an appropriate investment in current facilities to relieve congestion. Furthermore, it would enable the ranking or prioritisation of bottlenecks since bottleneck removal and its associated impact alleviation are hampered by limited sources. It is imperative that transportation jurisdiction understand and identify the basis for ranking bottlenecks by exploring: how often they are active; how long it takes the congestion to disappear; and how many miles of road are affected. Previous bottleneck identification schemes have focused on identifying congestion with little attention to distinguishing the recurrent level at the same ‘bottleneck’ location. In contrast to traditional schemes, a data-driven approach for identifying recurrent bottlenecks is introduced, using probe vehicle speed reports. The historical spatiotemporal characteristics of bottlenecks are investigated through a comprehensive analysis of 2253 miles of all state-wide interstates in North Carolina. Using the characteristics determined the recurrent bottleneck locations with a historical time span of bottleneck activation are revealed and tested. The findings of the proposed identification schemes generate critical information in order to quantify and diagnose a bottleneck and its associated impact area. DA - 2018/10// PY - 2018/10// DO - 10.1049/iet-its.2017.0284 VL - 12 IS - 8 SP - 756-764 SN - 1751-9578 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85053217294&partnerID=MN8TOARS ER - TY - JOUR TI - Multivariate bias corrections of mechanistic water quality model predictions AU - Libera, Dominic A. AU - Sankarasubramanian, A. T2 - Journal of Hydrology AB - Water quality networks usually do not include observations on a continuous timescale over a long period. Statistical models that use streamflow and mechanistic models that use meteorological information and land-use are commonly employed to develop continuous streamflow and nutrient records. Given the availability of long meteorological records, mechanistic models have the potential to develop continuous water quality records, but such predictions suffer from systematic biases on both streamflow and water quality constituents. This study proposes a multivariate bias correction technique based on canonical correlation analysis (CCA) – a dimension reduction technique based on multivariate multiple regression – that reduces the bias in both streamflow and loadings simultaneously by preserving the cross-correlation. We compare the performance of CCA with linear regression (LR) in removing the systematic bias from the SWAT model forced with precipitation and temperature for three selected watersheds from the Southeastern US. First, we compare the performance of CCA with LR in removing the bias in SWAT model outputs in predicting the observed streamflow and total nitrogen (TN) loadings from the Water Quality Network (WQN) dataset. We also evaluate the potential of CCA in removing the bias in SWAT model predictions at daily and monthly time scales by considering the LOADEST model predicted loadings as the predictand for CCA and LR. Evaluation of CCA with the observed dataset and at daily and streamflow time scales shows that the proposed multivariate technique not only reduces the bias in the cross-correlation between streamflow and loadings, but also improves the joint probability of estimating observed streamflow and loadings. Potential implications of the proposed bias-correction technique, CCA, in water quality forecasting and management are also discussed. DA - 2018/9// PY - 2018/9// DO - 10.1016/j.jhydrol.2018.07.043 VL - 564 SP - 529-541 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/j.jhydrol.2018.07.043 DB - Crossref KW - Multivariate KW - Bias correction KW - Mechanistic models KW - Water quality modeling ER - TY - JOUR TI - Allocating countermeasures to defend water distribution systems against terrorist attack AU - Monroe, Jacob AU - Ramsey, Elizabeth AU - Berglund, Emily T2 - Reliability Engineering & System Safety AB - Water distribution networks are critical infrastructure systems that are vulnerable to terrorist attack. Water utility management has the goal of protecting public health by allocating countermeasures, including security equipment and personnel, as a first line of defense. A malevolent actor may select an attack location, however, using a set of unknown priorities that include performance and susceptibility criteria. This research develops a multi-agent framework to simulate the attack and defense of a distribution system to analyze security resource allocation strategies for protecting against chemical contamination events. A single period attacker-defender game is simulated, in which an attacker seeks to contaminate a system node with high attack utility, and a group of defenders seeks to minimize the public health impact from intentional attack. Terrorist agent decisions are simulated using a multi-attribute utility function, and multiple cases are constructed to simulate alternative rankings of criteria. The water utility manager agent assigns security personnel and deterrent security equipment to nodes using one of three security resource allocation strategies. The agent-based modeling framework is applied to simulate attack and defense for a virtual municipality, D-town. Strategies are evaluated based on the number of consumers exposed to a critical dose when a contaminant is released. DA - 2018/11// PY - 2018/11// DO - 10.1016/j.ress.2018.02.014 VL - 179 SP - 37-51 J2 - Reliability Engineering & System Safety LA - en OP - SN - 0951-8320 UR - http://dx.doi.org/10.1016/j.ress.2018.02.014 DB - Crossref KW - Water supply security KW - Countermeasures KW - Contamination event KW - Police officers KW - Security equipment KW - Physical infrastructure network ER - TY - JOUR TI - Treating Coal Ash with Microbial-Induced Calcium Carbonate Precipitation AU - Safavizadeh, S. AU - Montoya, B. M. AU - Gabr, M. A. T2 - Journal of Geotechnical and Geoenvironmental Engineering DA - 2018/11// PY - 2018/11// DO - 10.1061/(ASCE)GT.1943-5606.0001956 VL - 144 IS - 11 SP - 02818003 J2 - J. Geotech. Geoenviron. Eng. LA - en OP - SN - 1090-0241 1943-5606 UR - http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001956 DB - Crossref ER - TY - JOUR TI - Preventing falls: Choosing compatible Fall Protection Supplementary Devices (FPSD) for bridge maintenance work using virtual prototyping AU - Zuluaga, Carlos M. AU - Albert, Alex T2 - SAFETY SCIENCE AB - Apart from struck-by safety incidents, fall-related injuries are a major concern in bridge maintenance work. To protect against falls from bridge decks, maintenance workers largely rely on existing bridge guardrails. However, a large number of bridge guardrails do not comply with the regulatory height requirement of 42 ± 3 in. for sufficient fall protection – although appropriate for vehicular traffic. To address this fall protection issue, a few departments of transportation (DOTs) have adopted Fall Protection Supplementary Devices (FPSDs). These devices are temporarily installed on existing bridge guardrails to sufficiently increase the barrier height while work is performed on bridge decks. However, not all FPSDs are compatible with every bridge guardrail. Therefore, to provide sufficient protection, DOT decision makers are tasked with identifying FPSDs that are compatible for each guardrail application. This generally has involved physically installing FPSDs and assessing compatibility on a trial-and-error basis. The use of such inefficient techniques have resulted in significant errors, wasted resources, productivity losses, and an increased likelihood of struck-by safety incidents. To address this issue, the objective of this study is to propose an efficient, cost-effective, and safe approach to assessing compatibility using virtual prototyping methods. In addition, to illustrate the use of the proposed method, a case example of the compatibility testing between two bridge guardrails in North Carolina and three separate FPSDs is presented. It is expected that the proposed method will provide a useful mechanism for DOTs to select suitable FPSDs to protect their workforce. DA - 2018/10// PY - 2018/10// DO - 10.1016/j.ssci.2017.08.006 VL - 108 SP - 238-247 SN - 1879-1042 KW - Bridges KW - Guardrails KW - Fall protection KW - Safety management KW - Construction safety KW - 3D modeling ER - TY - JOUR TI - On the practical usefulness of least squares for assessing uncertainty in hydrologic and water quality predictions AU - Del Giudice, D. AU - Muenich, R. L. AU - Kalcic, M. M. AU - Bosch, N. S. AU - Scavia, D. AU - Michalak, A. M. T2 - ENVIRONMENTAL MODELLING & SOFTWARE AB - Sophisticated methods for uncertainty quantification have been proposed for overcoming the pitfalls of simple statistical inference in hydrology. The implementation of such methods is conceptually and computationally challenging, however, especially for large-scale models. Here, we explore whether there are circumstances in which simple approaches, such as least squares, produce comparably accurate and reliable predictions. We do so using three case studies, with two involving a small sewer catchment with limited calibration data, and one an agricultural river basin with rich calibration data. We also review additional published case studies. We find that least squares performs similarly to more sophisticated approaches such as a Bayesian autoregressive error model in terms of both accuracy and reliability if calibration periods are long or if the input data and the model have minimal bias. Overall, we find that, when mindfully applied, simple statistical methods such as least squares can still be useful for uncertainty quantification. DA - 2018/7// PY - 2018/7// DO - 10.1016/j.envsoft.2018.03.009 VL - 105 SP - 286-295 SN - 1873-6726 KW - Uncertainty assessment KW - Mechanistic modeling KW - Surface hydrology KW - Water quality KW - Least squares KW - Statistical inference ER - TY - JOUR TI - Imaging of two-dimensional unsaturated moisture flows in uncracked and cracked cement-based materials using electrical capacitance tomography AU - Voss, A. AU - Hanninen, N. AU - Pour-Ghaz, M. AU - Vauhkonen, M. AU - Seppanen, A. T2 - Materials and Structures DA - 2018/// PY - 2018/// DO - 10.1617/s11527-018-1195-y VL - 51 IS - 3 ER - TY - JOUR TI - Case study comparison of functional vs. organic stability approaches for assessing threat potential at closed landfills in the USA AU - Sean T. O'Donnell, AU - Caldwell, Michael D. AU - Barlaz, Morton A. AU - Morris, Jeremy W. F. T2 - WASTE MANAGEMENT AB - Municipal solid waste (MSW) landfills in the USA are regulated under Subtitle D of the Resource Conservation and Recovery Act (RCRA), which includes the requirement to protect human health and the environment (HHE) during the post-closure care (PCC) period. Several approaches have been published for assessment of potential threats to HHE. These approaches can be broadly divided into organic stabilization, which establishes an inert waste mass as the ultimate objective, and functional stability, which considers long-term emissions in the context of minimizing threats to HHE in the absence of active controls. The objective of this research was to conduct a case study evaluation of a closed MSW landfill using long-term data on landfill gas (LFG) production, leachate quality, site geology, and solids decomposition. Evaluations based on both functional and organic stability criteria were compared. The results showed that longer periods of LFG and leachate management would be required using organic stability criteria relative to an approach based on functional stability. These findings highlight the somewhat arbitrary and overly stringent nature of assigning universal stability criteria without due consideration of the landfill’s hydrogeologic setting and potential environmental receptors. This supports previous studies that advocated for transition to a passive or inactive control stage based on a performance-based functional stability framework as a defensible mechanism for optimizing and ending regulatory PCC. DA - 2018/5// PY - 2018/5// DO - 10.1016/j.wasman.2018.02.001 VL - 75 SP - 415-426 SN - 1879-2456 KW - Post-closure care KW - Leachate KW - Landfill gas KW - Settlement KW - EPCC methodology ER - TY - JOUR TI - An integrated approach to place Green Infrastructure strategies in marginalized communities and evaluate stormwater mitigation AU - Garcia-Cuerva, Laura AU - Berglund, Emily Zechman AU - Rivers, Louie, III T2 - Journal of Hydrology AB - Increasing urbanization augments impervious surface area, which results in increased run off volumes and peak flows. Green Infrastructure (GI) approaches are a decentralized alternative for sustainable urban stormwater and provide an 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 explores GI-based management strategies that are evaluated at the watershed scale to improve hydrological performance by mitigating storm water run off volumes and peak flows. GI deployment strategies are developed to address environmental justice issues by prioritizing placement in communities that are underprivileged and locations with high outreach potential. A hydrologic/hydraulic stormwater model is developed using the Storm Water Management Model (SWMM 5.1) to simulate the impacts of alternative management strategies. Management scenarios include the implementation of rain water harvesting in private households, the decentralized implementation of bioretention cells in private households, the centralized implementation of bioretention cells in municipally owned vacant land, and combinations of those strategies. Realities of implementing GI on private and public lands are taken into account to simulate various levels of coverage and routing for bioretention cell scenarios. The effects of these strategies are measured by the volumetric reduction of run off and reduction in peak flow; social benefits are not evaluated. This approach is applied in an underprivileged community within the Walnut Creek Watershed in Raleigh, North Carolina. DA - 2018/4// PY - 2018/4// DO - 10.1016/j.jhydrol.2018.02.066 VL - 559 SP - 648-660 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/j.jhydrol.2018.02.066 DB - Crossref KW - Urban stormwater KW - Low impact development KW - Hydrologic/Hydraulic modeling KW - Environmental justice KW - Bioretention cells KW - Rainwater harvesting ER - TY - JOUR TI - Simulation of Constrained Variables in Engineering Risk Analyses AU - Tadinada, Sashi Kanth AU - Gupta, Abhinav T2 - AMERICAN STATISTICIAN AB - The problem of sampling random variables with overlapping pdfs subject to inequality constraints is addressed. Often, the values of physical variables in an engineering model are interrelated. This mutual dependence imposes inequality constraints on the random variables representing these parameters. Ignoring the interdependencies and sampling the variables independently can lead to inconsistency/bias. We propose an algorithm to generate samples of constrained random variables that are characterized by typical continuous probability distributions and are subject to different kinds of inequality constraints. The sampling procedure is illustrated for various representative cases and one realistic application to simulation of structural natural frequencies. DA - 2018/// PY - 2018/// DO - 10.1080/00031305.2016.1255660 VL - 72 IS - 2 SP - 130-139 SN - 1537-2731 KW - Constraints between random variables KW - Modeling uncertainties KW - Monte Carlo simulation KW - Random sampling ER - TY - JOUR TI - Seasonally Varying Secondary Organic Aerosol Formation From In-Situ Oxidation of Near-Highway Air AU - Saha, Provat K. AU - Reece, Stephen M. AU - Grieshop, Andrew P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - The extent to which motor vehicles contribute to ambient secondary organic aerosol (SOA) remains uncertain. Here, we present in situ measurements of SOA formation at a near-highway site with substantial tree-cover 10 m from Interstate 40 near Durham, North Carolina. In July 2015 (summer) and February 2016 (winter), we exposed ambient air to a range of oxidant (O3 and OH) concentrations in an oxidation flow reactor (OFR), resulting in hours to weeks of equivalent atmospheric aging. We observed substantial seasonal variation in SOA formation upon OFR aging; diurnally varying OA enhancements of ∼3–8 μg m–3 were observed in summer and significantly lower enhancements (∼0.5–1 μg m–3) in winter. Measurements in both seasons showed consistent changes in bulk OA properties (chemical composition; volatility) with OFR aging. Mild increases in traffic-related SOA precursors during summer partly explains the seasonal variation. However, biogenic emissions, with sharp temperature dependence, appear to dominate summer OFR-SOA. Our analysis indicates that SOA observed in the OFR is similar (within a factor of 2) to that predicted to form from traffic and biogenic precursors using literature yields, especially in winter. This study highlights the utility of the OFR for studying the prevalence of SOA precursors in complex real-world settings. DA - 2018/7/3/ PY - 2018/7/3/ DO - 10.1021/acs.est.8b01134 VL - 52 IS - 13 SP - 7192-7202 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.8b01134 ER - TY - JOUR TI - Resilient modulus prediction of soft low-plasticity Piedmont residual soil using dynamic cone penetrometer AU - Hamed Mousavi, S. AU - Gabr, Mohammed A. AU - Borden, Roy H. T2 - Journal of Rock Mechanics and Geotechnical Engineering AB - Dynamic cone penetrometer (DCP) has been used for decades to estimate the shear strength and stiffness properties of the subgrade soils. There are several empirical correlations in the literature to predict the resilient modulus values at only a specific stress state from DCP data, corresponding to the predefined thicknesses of pavement layers (a 50 mm asphalt wearing course, a 100 mm asphalt binder course and a 200 mm aggregate base course). In this study, field-measured DCP data were utilized to estimate the resilient modulus of low-plasticity subgrade Piedmont residual soil. Piedmont residual soils are in-place weathered soils from igneous and metamorphic rocks, as opposed to transported or compacted soils. Hence the existing empirical correlations might not be applicable for these soils. An experimental program was conducted incorporating field DCP and laboratory resilient modulus tests on “undisturbed” soil specimens. The DCP tests were carried out at various locations in four test sections to evaluate subgrade stiffness variation laterally and with depth. Laboratory resilient modulus test results were analyzed in the context of the mechanistic-empirical pavement design guide (MEPDG) recommended universal constitutive model. A new approach for predicting the resilient modulus from DCP by estimating MEPDG constitutive model coefficients (k1, k2 and k3) was developed through statistical analyses. The new model is capable of not only taking into account the in situ soil condition on the basis of field measurements, but also representing the resilient modulus at any stress state which addresses a limitation with existing empirical DCP models and its applicability for a specific case. Validation of the model is demonstrated by using data that were not used for model development, as well as data reported in the literature. DA - 2018/4// PY - 2018/4// DO - 10.1016/j.jrmge.2017.10.007 VL - 10 IS - 2 SP - 323-332 J2 - Journal of Rock Mechanics and Geotechnical Engineering LA - en OP - SN - 1674-7755 UR - http://dx.doi.org/10.1016/j.jrmge.2017.10.007 DB - Crossref KW - Dynamic cone penetrometer (DCP) KW - Resilient modulus KW - Mechanistic-empirical pavement design guide (MEPDG) KW - Residual soils KW - Subgrade soils ER - TY - JOUR TI - Protecting Bridge Maintenance Workers from Falls: Evaluation and Selection of Compatible Fall Protection Supplementary Devices AU - Zuluaga, Carlos M. AU - Albert, Alex AU - Arroyo, Paz T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Falls from bridge decks are a common issue among highway and bridge maintenance workers. These workers generally rely on existing bridge guardrails for their protection against falls when working on bridge decks. Unfortunately, a large number of bridge guardrails do not provide the required barrier height of 107±8 cm (42±3 in.) for sufficient protection. To overcome this issue, a few departments of transportation (DOTs) have recently begun installing Fall Protection Supplementary Devices (FPSDs) on bridge guardrails—to temporarily increase the overall barrier height during work. However, many manufactured and marketed FPSDs are not compatible—or do not firmly attach onto every bridge guardrail. Therefore, workers are often tasked with assessing the compatibility of FPSDs with particular bridge guardrails before initiating work. Traditionally, this has been performed using an inefficient trial-and-error based approach—where potential FPSDs are procured, transported, and iteratively tested with a number of bridge guardrails. Apart from this inefficient testing procedure, current literature does not offer any guidance on the selection of efficient FPSDs based on the advantages they offer. Therefore, compatible FPSD systems that are not optimal for work efficiency, productivity, and safety are commonly adopted in practice. To resolve these challenges, the current research focused on identifying compatible FPSDs—that offer the most advantages—for 12 bridge guardrails that appear across 11,000 bridges in North Carolina. The study objectives were accomplished by (1) building virtual prototypes of existing bridge guardrails and FPSD systems and assessing compatibility in a virtual setting; (2) identifying desirable FPSD characteristics that can lead to improvements in work-efficiency, productivity, and safety (i.e., advantages); and (3) evaluating potential FPSD systems for each guardrail using the structured Choosing by Advantages (CBA) method—to identify FPSD systems that offer the most important set of advantages. The study addresses a nationwide safety issue experienced by all transportation agencies in the United States and beyond. It is expected that the findings will encourage more DOTs to adopt efficient fall protection measures and systems to protect their workforce. DA - 2018/8// PY - 2018/8// DO - 10.1061/(asce)co.1943-7862.0001529 VL - 144 IS - 8 SP - SN - 1943-7862 KW - Construction safety KW - Fall protection KW - Virtual prototyping KW - Highway worker safety KW - Injury prevention KW - Choosing by advantages ER - TY - JOUR TI - Microbial ecological succession during municipal solid waste decomposition AU - Staley, Bryan F. AU - de los Reyes, Francis L. AU - Wang, Ling AU - Barlaz, Morton A. T2 - Applied Microbiology and Biotechnology DA - 2018/4/28/ PY - 2018/4/28/ DO - 10.1007/s00253-018-9014-5 VL - 102 IS - 13 SP - 5731-5740 J2 - Appl Microbiol Biotechnol LA - en OP - SN - 0175-7598 1432-0614 UR - http://dx.doi.org/10.1007/s00253-018-9014-5 DB - Crossref KW - Anerobic KW - Landfill KW - Microbial community KW - 16S rRNA gene KW - Refuse decomposition KW - MSW ER - TY - JOUR TI - Fatigue Performance Analysis of Pavements with RAP Using Viscoelastic Continuum Damage Theory AU - Wang, Yizhuang David AU - Keshavarzi, Behrooz AU - Kim, Youngsoo Richard T2 - KSCE JOURNAL OF CIVIL ENGINEERING DA - 2018/6// PY - 2018/6// DO - 10.1007/s12205-018-2648-0 VL - 22 IS - 6 SP - 2118-2125 SN - 1976-3808 KW - Reclaimed Asphalt Pavement (RAP) KW - fatigue cracking KW - Simplified Viscoelastic Continuum Damage (S-VECD) model KW - D-R failure criterion KW - S-app KW - FlexPAVE (TM) ER - TY - ER - TY - CONF TI - Effect of seawater on the mechanical properties of cement grout used for formation of micropiles in marine applications AU - Ahsanuzzaman, M. AU - Gabr, Mohammed AU - Borden, R. H. C2 - 2018/// C3 - Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades DA - 2018/// DO - 10.1061/9780784481592.039 SP - 394–403 M1 - 296 ER - TY - CONF TI - Effect of Microbial Induced Calcium Carbonate Precipitation on Compressibility and Hydraulic Conductivity of Fly Ash AU - Safavizadeh, Shahin AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - IFCEE 2018 AB - The morphology and chemical composition of fly ash render the material unique in comparison to natural sediments. Fly ash deposited in ash ponds can possess a loose, saturated, and contractive structure with a tendency to collapse under induced shear stresses. Compressibility and hydraulic conductivity are the two main parameters affecting the stability of this material in ash ponds. Microbial induced calcium carbonate precipitation (MICP) is a novel approach, which has been widely studied to improve engineering properties of soils. In this study, the MICP treatment process is applied to a Class-F fly ash material to assess its effect on the two mentioned parameters. Modified odometer testing was developed with the ability to inject the treatment solution, measure the induced pressure during injection, and monitor the shear wave velocity of the test specimens. The specimens were successfully treated using MICP, reaching predetermined target shear wave velocities. The results of compressibility on treated and untreated specimens indicate that MICP decreases the compressibility of the studied material while the hydraulic conductivity decreased by only one order of magnitude or less. The shear wave velocity of the treated and untreated specimens converged to the same value while the vertical applied stress increased, indicating the calcium carbonate bond breakage between particles. C2 - 2018/6/6/ C3 - IFCEE 2018 DA - 2018/6/6/ DO - 10.1061/9780784481592.008 SP - 69–79 M1 - 296 PB - American Society of Civil Engineers UR - http://dx.doi.org/10.1061/9780784481592.008 ER - TY - JOUR TI - Causal identification of transit-induced gentrification and spatial spillover effects: The case of the Denver light rail AU - Bardaka, Eleni AU - Delgado, Michael S. AU - Florax, Raymond J. G. M. T2 - JOURNAL OF TRANSPORT GEOGRAPHY AB - We test the hypothesis of transit-induced gentrification for the Regional Transportation District light rail system in Denver, CO. We use a quasi-experimental spatial econometric approach, the spatial difference-in-differences model, to measure the causal relationship between urban rail investments and gentrification, which allows us to capture the average direct and indirect (spatial spillover) effects of urban rail on several socioeconomic measures of gentrification. We further account for unobserved heterogeneity and spatial dependence via the use of a panel data estimator with spatial error components. Our analysis shows that the installation of a light rail station significantly increases household income and housing values in neighborhoods up to one mile from the station. DA - 2018/7// PY - 2018/7// DO - 10.1016/j.jtrangeo.2018.06.025 VL - 71 SP - 15-31 SN - 1873-1236 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85049741706&partnerID=MN8TOARS KW - Spatial difference-in-differences KW - Causal identification KW - Urban rail KW - Gentrification KW - Spatial spillover effects KW - Unobserved heterogeneity ER - TY - JOUR TI - Application of a life cycle model for european union policy-driven waste management decision making in emerging economies AU - Stanisavljevic, N. AU - Levis, J. W. AU - Barlaz, M. A. T2 - Journal of Industrial Ecology AB - Summary Solid waste life cycle modeling has predominantly focused on developed countries, but there are significant opportunities to assist developing and transition economies to minimize the environmental impact of solid waste management (SWM). Serbia is representative of a transition country and most (92%) of its waste is landfilled. As a Candidate European Union (EU) country, Serbia is expected to implement SWM strategies that meet EU directives. The Solid Waste Life‐Cycle Optimization Framework (SWOLF) was used to evaluate scenarios that meet EU goals by 2030. Scenarios included combinations of landfills, anaerobic digestion, composting, material recovery facilities (MRFs), waste‐to‐energy (WTE) combustion, and the use of refuse‐derived fuel in cement kilns. Each scenario was evaluated with and without separate collection of recyclables. Modeled impacts included cost, climate change, cumulative fossil energy demand, acidification, eutrophication, photochemical oxidation, total eco‐toxicity, and total human toxicity. Trade‐offs among the scenarios were evaluated because no scenario performed best in every category. In general, SWM strategies that incorporated processes that recover energy and recyclable materials performed well across categories, whereas scenarios that did not include energy recovery performed poorly. Emissions offsets attributable to energy recovery and reduced energy requirements associated with remanufacturing of recovered recyclables had the strongest influence on the results. The scenarios rankings were robust under parametric sensitivity analysis, except when the marginal electricity fuel source changed from coal to natural gas. Model results showed that the use of existing infrastructure, energy recovery, and efficient recovery of recyclables from mixed waste can reduce environmental emissions at relatively low cost. DA - 2018/// PY - 2018/// DO - 10.1111/jiec.12564 VL - 22 IS - 2 SP - 341-355 ER - TY - CONF TI - A new framework for identifying cementation level of MICP-treated sands AU - Nafisi, A. AU - Montoya, B.M. AB - Microbial induced calcium carbonate precipitation (MICP) is a ground improvement technique that can be employed to increase soil stiffness and shear strength. Based on the treatment’s objectives, soil properties are improved to reach different levels of cementation. Shear wave velocity and mass of calcium carbonate can be used to categorize treated soils into various levels of cementation. However, the obtained results show that these two parameters are not sufficient in categorizing cementation and may be misleading. Therefore, a new framework which considers particle size, the dependency of shear modulus on confinement, shear wave velocity, and calcium carbonate content is proposed. In this paper, three types of poorly graded sands with different particle sizes were used. Shear modulus was measured at varying levels of cementation and confinement pressures to find out the amount of dependency of small strain shear modulus on confining pressure. According to the results, the finest soil needs more calcium carbonate to reach heavily cemented level, but the final shear wave velocity is lower compared to the coarser sands. Based on the obtained results, n (the slope of log Gmaxagainst log of mean effective stress) values for lightly, moderately, and heavily MICP-sands are about 0.4, 0.3, and less than 0.1, respectively. C2 - 2018/// C3 - Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades DA - 2018/// DO - 10.1061/9780784481592.005 SP - 37–47 M1 - 296 UR - http://www.lib.ncsu.edu/resolver/1840.20/36315 N1 - annote: Nafisi, A., & Montoya, B. M. (2018). A new framework for identifying cementation level of MICP-treated sands. In Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades (pp. 37–47). RN - annote: Nafisi, A., & Montoya, B. M. (2018). A new framework for identifying cementation level of MICP-treated sands. In Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades (pp. 37–47). ER - TY - JOUR TI - Toward effective adoption of secure software development practices AU - Al-Amin, Shams AU - Ajmeri, Nirav AU - Du, Hongying AU - Berglund, Emily Z. AU - Singh, Munindar P. T2 - SIMULATION MODELLING PRACTICE AND THEORY AB - Security tools, including static and dynamic analysis tools, can guide software developers to identify and fix potential vulnerabilities in their code. However, the use of security tools is not common among developers. The goal of this research is to develop a framework for modeling the adoption of security practices in software development and to explore sanctioning mechanisms that may promote greater adoption of these practices among developers. We propose a multiagent simulation framework that incorporates developers and manager roles, where developers maximize task completion and compliance with security policies, and the manager enforces sanctions based on functionality and security of the project. The adoption of security practices emerges through the interaction of manager and developer agents in time-critical projects. Using the framework, we evaluate the adoption of security practices for developers with different preferences and strategies under individual and group sanctions. We use a real case study for demonstrating the model and initialize the occurrence of bugs using a 13 year database of bug reports for the Eclipse Java Development Tools. Results indicate that adoption of security practices are significantly dictated by the preferences of the developers. We also observed that repetitive sanctions may cause lower retention of developers and an overall decrease in security practices. The model provides comparison of security adoption in developers with different preferences and provides guidance for managers to identify appropriate sanctioning mechanism for increasing the adoption of security tools in software development. DA - 2018/6// PY - 2018/6// DO - 10.1016/j.simpat.2018.03.006 VL - 85 SP - 33-46 SN - 1878-1462 KW - Multiagent system KW - Security practices KW - Adoption KW - Decision theory KW - Sanction ER - TY - JOUR TI - Time-Dependent Tension-Stiffening Mechanics of Fiber-Reinforced and Ultra-High-Performance Fiber-Reinforced Concrete AU - Sturm, A. B. AU - Visintin, P. AU - Oehlers, D. J. AU - Seracino, R. T2 - Journal of Structural Engineering AB - The tension-stiffening behavior of fiber-reinforced concrete is of fundamental importance for the characterization of crack widths and spacings as well as determination of the tensile response of fiber-reinforced concrete members with internal reinforcement. In this paper, a model is presented for the tension-stiffening behavior of strain-softening and strain-hardening fiber-reinforced and ultra-high-performance fiber-reinforced concrete with an allowance for the long-term creep and shrinkage effects of the concrete. Closed-form analytical solutions are derived to describe the crack spacings and load slip behavior assuming either a simplified linear ascending bond stress–slip relationship or a more realistic bond stress–slip relationship from the literature. Further, it is shown for design how the stiffness of the reinforcement can be characterized using an effective modular ratio, which can easily be incorporated into member analysis techniques to characterize the serviceability behavior of flexural members. Finally, the results are validated against a broad range of fiber-reinforced concretes of normal, high, and ultra-high strength, thus demonstrating validity for a wide range of different fiber-reinforced concretes (FRCs). DA - 2018/8// PY - 2018/8// DO - 10.1061/(ASCE)ST.1943-541X.0002107 VL - 144 IS - 8 SP - 04018122 J2 - J. Struct. Eng. LA - en OP - SN - 0733-9445 1943-541X UR - http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0002107 DB - Crossref KW - RC beams KW - Tension stiffening KW - Crack widths KW - Crack spacing KW - Concrete shrinkage KW - Concrete creep KW - Bond slip KW - Partial interaction ER - TY - JOUR TI - Real-world fuel use and gaseous emission rates for flex fuel vehicles operated on E85 versus gasoline AU - Delavarrafiee, Maryam AU - Frey, H. Christopher T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Flex fuel vehicles (FFVs) typically operate on gasoline or E85, an 85%/15% volume blend of ethanol and gasoline. Differences in FFV fuel use and tailpipe emission rates are quantified for E85 versus gasoline based on real-world measurements of five FFVs with a portable emissions measurement system (PEMS), supplemented chassis dynamometer data, and estimates from the Motor Vehicle Emission Simulator (MOVES) model. Because of inter-vehicle variability, an individual FFV may have higher nitrogen oxide (NOx) or carbon monoxide (CO) emission rates on E85 versus gasoline, even though average rates are lower. Based on PEMS data, the comparison of tailpipe emission rates for E85 versus gasoline is sensitive to vehicle-specific power (VSP). For example, although CO emission rates are lower for all VSP modes, they are proportionally lowest at higher VSP. Driving cycles with high power demand are more advantageous with respect to CO emissions, but less advantageous for NOx. Chassis dynamometer data are available for 121 FFVs at 50,000 useful life miles. Based on the dynamometer data, the average difference in tailpipe emissions for E85 versus gasoline is -23% for NOx, -30% for CO, and no significant difference for hydrocarbons (HC). To account for both the fuel cycle and tailpipe emissions from the vehicle, a life cycle inventory was conducted. Although tailpipe NOx emissions are lower for E85 versus gasoline for FFVs and thus benefit areas where the vehicles operate, the life cycle NOx emissions are higher because the NOx emissions generated during fuel production are higher. The fuel production emissions take place typically in rural areas. Although there are not significant differences in the total HC emissions, there are differences in HC speciation. The net effect of lower tailpipe NOx emissions and differences in HC speciation on ozone formation should be further evaluated.Reported comparisons of flex fuel vehicle (FFV) tailpipe emission rates for E85 versus gasoline have been inconsistent. To date, this is the most comprehensive evaluation of available and new data. The large range of inter-vehicle variability illustrates why prior studies based on small sample sizes led to apparently contradictory findings. E85 leads to significant reductions in tailpipe nitrogen oxide (NOx) and carbon monoxide (CO) emission rates compared with gasoline, indicating a potential benefit for ozone air quality management in NOx-limited areas. The comparison of FFV tailpipe emissions between E85 and gasoline is sensitive to power demand and driving cycles. DA - 2018/// PY - 2018/// DO - 10.1080/10962247.2017.1405097 VL - 68 IS - 3 SP - 235-254 SN - 2162-2906 UR - https://doi.org/10.1080/10962247.2017.1405097 ER - TY - JOUR TI - Maximizing ozone signals among chemical, meteorological, and climatological variability AU - Brown-Steiner, Benjamin AU - Selin, Noelle E. AU - Prinn, Ronald G. AU - Monier, Erwan AU - Tilmes, Simone AU - Emmons, Louisa AU - Garcia-Menendez, Fernando T2 - Atmospheric Chemistry and Physics AB - Abstract. The detection of meteorological, chemical, or other signals in modeled or observed air quality data – such as an estimate of a temporal trend in surface ozone data, or an estimate of the mean ozone of a particular region during a particular season – is a critical component of modern atmospheric chemistry. However, the magnitude of a surface air quality signal is generally small compared to the magnitude of the underlying chemical, meteorological, and climatological variabilities (and their interactions) that exist both in space and in time, and which include variability in emissions and surface processes. This can present difficulties for both policymakers and researchers as they attempt to identify the influence or signal of climate trends (e.g., any pauses in warming trends), the impact of enacted emission reductions policies (e.g., United States NOx State Implementation Plans), or an estimate of the mean state of highly variable data (e.g., summertime ozone over the northeastern United States). Here we examine the scale dependence of the variability of simulated and observed surface ozone data within the United States and the likelihood that a particular choice of temporal or spatial averaging scales produce a misleading estimate of a particular ozone signal. Our main objective is to develop strategies that reduce the likelihood of overconfidence in simulated ozone estimates. We find that while increasing the extent of both temporal and spatial averaging can enhance signal detection capabilities by reducing the noise from variability, a strategic combination of particular temporal and spatial averaging scales can maximize signal detection capabilities over much of the continental US. For signals that are large compared to the meteorological variability (e.g., strong emissions reductions), shorter averaging periods and smaller spatial averaging regions may be sufficient, but for many signals that are smaller than or comparable in magnitude to the underlying meteorological variability, we recommend temporal averaging of 10–15 years combined with some level of spatial averaging (up to several hundred kilometers). If this level of averaging is not practical (e.g., the signal being examined is at a local scale), we recommend some exploration of the spatial and temporal variability to provide context and confidence in the robustness of the result. These results are consistent between simulated and observed data, as well as within a single model with different sets of parameters. The strategies selected in this study are not limited to surface ozone data and could potentially maximize signal detection capabilities within a broad array of climate and chemical observations or model output. DA - 2018/6/15/ PY - 2018/6/15/ DO - 10.5194/acp-18-8373-2018 VL - 18 IS - 11 SP - 8373-8388 J2 - Atmos. Chem. Phys. LA - en OP - SN - 1680-7324 UR - http://dx.doi.org/10.5194/acp-18-8373-2018 DB - Crossref ER - TY - JOUR TI - Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity AU - Kingsbury, Ryan S. AU - Flotron, Sophie AU - Zhu, Shan AU - Call, Douglas F. AU - Coronell, Orlando T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Ion exchange membranes (IEMs) are versatile materials relevant to a variety of water and waste treatment, energy production, and industrial separation processes. The defining characteristic of IEMs is their ability to selectively allow positive or negative ions to permeate, which is referred to as permselectivity. Measured values of permselectivity that equal unity (corresponding to a perfectly selective membrane) or exceed unity (theoretically impossible) have been reported for cation exchange membranes (CEMs). Such nonphysical results call into question our ability to correctly measure this crucial membrane property. Because weighing errors, temperature, and measurement uncertainty have been shown to not explain these anomalous permselectivity results, we hypothesized that a possible explanation are junction potentials that occur at the tips of reference electrodes. In this work, we tested this hypothesis by comparing permselectivity values obtained from bare Ag/AgCl wire electrodes (which have no junction) to values obtained from single-junction reference electrodes containing two different electrolytes. We show that permselectivity values obtained using reference electrodes with junctions were greater than unity for CEMs. In contrast, electrodes without junctions always produced permselectivities lower than unity. Electrodes with junctions also resulted in artificially low permselectivity values for AEMs compared to electrodes without junctions. Thus, we conclude that junctions in reference electrodes introduce two biases into results in the IEM literature: (i) permselectivity values larger than unity for CEMs and (ii) lower permselectivity values for AEMs compared to those for CEMs. These biases can be avoided by using electrodes without a junction. DA - 2018/4/17/ PY - 2018/4/17/ DO - 10.1021/acs.est.7b05317 VL - 52 IS - 8 SP - 4929-4936 SN - 1520-5851 ER - TY - JOUR TI - Improving wood properties for wood utilization through multi-omics integration in lignin biosynthesis AU - Wang, Jack P. AU - Matthews, Megan L. AU - Williams, Cranos M. AU - Shi, Rui AU - Yang, Chenmin AU - Tunlaya-Anukit, Sermsawat AU - Chen, Hsi-Chuan AU - Li, Quanzi AU - Liu, Jie AU - Lin, Chien-Yuan AU - Naik, Punith AU - Sun, Ying-Hsuan AU - Loziuk, Philip L. AU - Yeh, Ting-Feng AU - Kim, Hoon AU - Gjersing, Erica AU - Shollenberger, Todd AU - Shuford, Christopher M. AU - Song, Jina AU - Miller, Zachary AU - Huang, Yung-Yun AU - Edmunds, Charles W. AU - Liu, Baoguang AU - Sun, Yi AU - Lin, Ying-Chung Jimmy AU - Li, Wei AU - Chen, Hao AU - Peszlen, Ilona AU - Ducoste, Joel J. AU - Ralph, John AU - Chang, Hou-Min AU - Muddiman, David C. AU - Davis, Mark F. AU - Smith, Chris AU - Isik, Fikret AU - Sederoff, Ronald AU - Chiang, Vincent L. T2 - Nature Communications AB - A multi-omics quantitative integrative analysis of lignin biosynthesis can advance the strategic engineering of wood for timber, pulp, and biofuels. Lignin is polymerized from three monomers (monolignols) produced by a grid-like pathway. The pathway in wood formation of Populus trichocarpa has at least 21 genes, encoding enzymes that mediate 37 reactions on 24 metabolites, leading to lignin and affecting wood properties. We perturb these 21 pathway genes and integrate transcriptomic, proteomic, fluxomic and phenomic data from 221 lines selected from ~2000 transgenics (6-month-old). The integrative analysis estimates how changing expression of pathway gene or gene combination affects protein abundance, metabolic-flux, metabolite concentrations, and 25 wood traits, including lignin, tree-growth, density, strength, and saccharification. The analysis then predicts improvements in any of these 25 traits individually or in combinations, through engineering expression of specific monolignol genes. The analysis may lead to greater understanding of other pathways for improved growth and adaptation. DA - 2018/4/20/ PY - 2018/4/20/ DO - 10.1038/s41467-018-03863-z VL - 9 IS - 1 SP - J2 - Nat Commun LA - en OP - SN - 2041-1723 UR - http://dx.doi.org/10.1038/s41467-018-03863-z DB - Crossref ER - TY - JOUR TI - Effect of residential proximity on university student trip frequency by mode AU - Searcy, Sarah E. AU - Findley, Daniel J. AU - Huegy, Joseph B. AU - Ingram, Mei AU - Mei, Bing AU - Bhadury, Joyendu AU - Wang, Chao T2 - TRAVEL BEHAVIOUR AND SOCIETY AB - • A fractional polynomial regression was used to model university student trips. • Non-motorized trips comprise the majority of trips at short distances from campus. • Automobile and transit trips comprise the majority of trips at longer distances. • Services can be put close to students’ residences to maximize non-motorized trips. DA - 2018/7// PY - 2018/7// DO - 10.1016/j.tbs.2017.12.007 VL - 12 SP - 115-121 SN - 2214-3688 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039937263&partnerID=MN8TOARS ER - TY - JOUR TI - Editorial AU - Montoya, Brina M. T2 - ENVIRONMENTAL GEOTECHNICS DA - 2018/4// PY - 2018/4// DO - 10.1680/jenge.2018.5.2.67 VL - 5 IS - 2 SP - 67-68 SN - 2051-803X ER - TY - JOUR TI - Characterizing and Predicting Yelp Users' Behavior AU - Jayaprakasan, Parvathy AU - Uma, R. N. AU - Sankarasubramanian, A. T2 - HIGHLIGHTING THE IMPORTANCE OF BIG DATA MANAGEMENT AND ANALYSIS FOR VARIOUS APPLICATIONS AB - A business’ revenue is significantly dependent on Yelp user ratings (Luca, Reviews, reputation, and revenue: the case of Yelp.com. Harvard Business School Working Paper, No. 12-016, 2016; Anderson and Magruder J Econ J. 122(563):957–989, 2012). Knowing the characteristics of Yelp users will influence their business practices that would eventually help improve their Yelp ratings and consequently their revenue. We categorize Yelp users based on the average number of stars given by each user for their reviews. We determine the common characteristics and differences of users between these user groups; and determine whether these characteristics change by business category. We conclude that users whose average rating falls between 3.7 and 4.0 are the most influential and socially connected and that the type of business does not affect the characteristics of the users. Additionally, we design a two-stage predictive model to predict the average star rating of users given their features or attributes and compare its performance to standard models such as random forest and generalized additive model. DA - 2018/// PY - 2018/// DO - 10.1007/978-3-319-60255-4_2 VL - 27 SP - 17-35 SN - 2197-6511 ER - TY - JOUR TI - Variability in Coastal Flooding predictions due to forecast errors during Hurricane Arthur AU - Cyriac, R. AU - Dietrich, J.C. AU - Fleming, J.G. AU - Blanton, B.O. AU - Kaiser, C. AU - Dawson, C.N. AU - Luettich, R.A. T2 - Coastal Engineering AB - Storm surge prediction models rely on an accurate representation of the wind conditions. In this paper, we examine the sensitivity of surge predictions to forecast uncertainties in the track and strength of a storm (storm strength is quantified by the power dissipation of the associated wind field). This analysis is performed using Hurricane Arthur (2014), a Category 2 hurricane, which made landfall along the North Carolina (NC) coast in early July 2014. Hindcast simulations of a coupled hydrodynamic-wave model are performed on a large unstructured mesh to analyze the surge impact of Arthur along the NC coastline. The effects of Arthur are best represented by a post-storm data assimilated wind product with parametric vortex winds providing a close approximation. Surge predictions driven by forecast advisories issued by the National Hurricane Center (NHC) during Arthur are analyzed. The storm track predictions from the NHC improve over time. However, successive advisories predict an unrealistic increase in the storm's strength. Due to these forecast errors, the global root mean square errors of the predicted wind speeds and water levels increase as the storm approaches landfall. The relative impacts of the track and strength errors on the surge predictions are assessed by replacing forecast storm parameters with the best known post-storm information about Arthur. In a “constant track” analysis, Arthur's post storm determined track is used in place of the track predictions of the different advisories but each advisory retains its size and intensity predictions. In a “constant storm strength” analysis, forecast wind and pressure parameters are replaced by corresponding parameters extracted from the post storm analysis while each advisory retains its forecast storm track. We observe a strong correlation between the forecast errors and the wind speed predictions. However, the correlation between these errors and the forecast water levels is weak signifying a non-linear response of the shallow coastal waters to meteorological forcing. DA - 2018/7// PY - 2018/7// DO - 10.1016/j.coastaleng.2018.02.008 VL - 137 SP - 59-78 J2 - Coastal Engineering LA - en OP - SN - 0378-3839 UR - http://dx.doi.org/10.1016/j.coastaleng.2018.02.008 DB - Crossref KW - Hurricane Arthur (2014) KW - ADCIRC KW - North Carolina KW - Coastal flooding KW - Forecast uncertainty KW - HWind KW - GAHM ER - TY - JOUR TI - Utilizing Digital Image Correlation (DIC) in Asphalt Pavement Testing AU - Safavizadeh, S. A. AU - Wargo, A. AU - Kim, Y. Richard T2 - JOURNAL OF TESTING AND EVALUATION AB - The digital image correlation (DIC) technique as a displacement and strain measurement method is one of the newest measurement technologies employed in asphalt pavement testing. Although DIC was introduced for material testing in the early 1980s; this technology is not yet being used to its highest potential as a reliable and flexible method for measuring displacements and strains and, more importantly, for investigating cracking phenomena and fracture characteristics in asphalt pavement testing. This research aimed to study the requirements for ensuring a reliable and accurate DIC system and to demonstrate areas where the technique could be used to provide an edge over traditional measurement methods. Using proprietary two-dimensional DIC software, the parameters that affect the accuracy of test results were evaluated and the proper analysis configurations for investigating cracked areas were determined. The results showed that the DIC technique, if used properly, is an extremely powerful tool for studying damage progression and fracture characteristics in the fatigue and fracture testing of asphalt concrete. DA - 2018/5// PY - 2018/5// DO - 10.1520/jte20160262 VL - 46 IS - 3 SP - 984-998 SN - 1945-7553 KW - digital image correlation (DIC) KW - asphalt pavement KW - damage progression KW - crack propagation ER - TY - JOUR TI - Undrained Monotonic Shear Response of MICP-Treated Silty Sands AU - Zamani, A. AU - Montoya, B. M. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING AB - The effect of nonplastic fines on the undrained shear response of sand depends on many variables, including fines content, skeleton void ratio (es), interfine void ratio (ef), global void ratio (e), confining pressure, and relative density. This paper focuses on applying microbe-induced carbonate precipitation (MICP) to silty sands containing fines up to 35% to assess its effect on the undrained shear response. Sporocarcina pasteurii, an alkalophilic soil bacterium was used to catalyze the chemical reaction and induce calcium carbonate precipitation. Shear-wave velocity (Vs) measurements are used to assess improvement, with a target Vs of approximately 400 m/s. Undrained monotonic direct simple shear loading was used to compare the undrained shear response of untreated and MICP-treated specimens with similar preshear void ratios of 0.7±0.05. Decreased excess pore water pressure and flow behavior and increased undrained shear strength were the observed general changes due to MICP. The results presented here indicate that the effect of MICP on silty sands depends on relative density, fines content, and the fabric governing the structure of the soil. DA - 2018/6// PY - 2018/6// DO - 10.1061/(asce)gt.1943-5606.0001861 VL - 144 IS - 6 SP - SN - 1943-5606 KW - Cemented silty sand KW - Undrained shear strength KW - Shear-wave velocity KW - Microbial induced calcium carbonate precipitation KW - Sporocarcina pasteurii KW - Skeleton void ratio KW - Interfines void ratio ER - TY - JOUR TI - Trends in onroad transportation energy and emissions AU - Frey, H. Christopher T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO2, and emit other pollutants to which approximately 200,000 annual premature deaths are attributed. Improved vehicle energy efficiency and emission controls have helped offset growth in vehicle activity. New technologies are diffusing into the vehicle fleet in response to fuel efficiency and emission standards. Empirical assessment of vehicle emissions is challenging because of myriad fuels and technologies, intervehicle variability, multiple emission processes, variability in operating conditions, and varying capabilities of measurement methods. Fuel economy and emissions regulations have been effective in reducing total emissions of key pollutants. Real-world fuel use and emissions are consistent with official values in the United States but not in Europe or countries that adopt European standards. Portable emission measurements systems, which uncovered a recent emissions cheating scandal, have a key role in regulatory programs to ensure conformity between “real driving emissions” and emission standards. The global vehicle fleet will experience tremendous growth, especially in Asia. Although existing data and modeling tools are useful, they are often based on convenience samples, small sample sizes, large variability, and unquantified uncertainty. Vehicles emit precursors to several important secondary pollutants, including ozone and secondary organic aerosols, which requires a multipollutant emissions and air quality management strategy. Gasoline and diesel are likely to persist as key energy sources to mid-century. Adoption of electric vehicles is not a panacea with regard to greenhouse gas emissions unless coupled with policies to change the power generation mix. Depending on how they are actually implemented and used, autonomous vehicles could lead to very large reductions or increases in energy consumption. Numerous other trends are addressed with regard to technology, emissions controls, vehicle operations, emission measurements, impacts on exposure, and impacts on public health.Implications: Without specific policies to the contrary, fossil fuels are likely to continue to be the major source of on-road vehicle energy consumption. Fuel economy and emission standards are generally effective in achieving reductions per unit of vehicle activity. However, the number of vehicles and miles traveled will increase. Total energy use and emissions depend on factors such as fuels, technologies, land use, demographics, economics, road design, vehicle operation, societal values, and others that affect demand for transportation, mode choice, energy use, and emissions. Thus, there are many opportunities to influence future trends in vehicle energy use and emissions. DA - 2018/// PY - 2018/// DO - 10.1080/10962247.2018.1454357 VL - 68 IS - 6 SP - 514-563 SN - 2162-2906 UR - https://doi.org/10.1080/10962247.2018.1454357 ER - TY - JOUR TI - Sensitivity of Storm Surge Predictions to Atmospheric Forcing during Hurricane Isaac AU - Dietrich, J. C. AU - Muhammad, A. AU - Curcic, M. AU - Fathi, A. AU - Dawson, C. N. AU - Chen, S. S. AU - Luettich, R. A., Jr. T2 - Journal of Waterway, Port, Coastal, and Ocean Engineering AB - Storm surge and overland flooding can be predicted with computational models at high levels of resolution. To improve efficiency in forecasting applications, surge models often use atmospheric forcing from parametric vortex models, which represent the surface pressures and wind fields with a few storm parameters. The future of storm surge prediction could involve real-time coupling of surge and full-physics atmospheric models; thus, their accuracies must be understood in a real hurricane scenario. The authors compare predictions from a parametric vortex model (using forecast tracks from the National Hurricane Center) and a full-physics coupled atmosphere-wave-ocean model during Hurricane Isaac (2012). The predictions are then applied within a tightly coupled, wave and surge modeling system describing the northern Gulf of Mexico and the floodplains of southwest Louisiana. It is shown that, in a hindcast scenario, a parametric vortex model can outperform a data-assimilated wind product, and given reasonable forecast advisories, a parametric vortex model gives reasonable surge forecasts. However, forecasts using a full-physics coupled model outperformed the forecast advisories and improved surge forecasts. Both approaches are valuable for forecasting the coastal impacts associated with tropical cyclones. DA - 2018/1// PY - 2018/1// DO - 10.1061/(asce)ww.1943-5460.0000419 VL - 144 IS - 1 SP - 04017035 J2 - J. Waterway, Port, Coastal, Ocean Eng. LA - en OP - SN - 0733-950X 1943-5460 UR - http://dx.doi.org/10.1061/(ASCE)WW.1943-5460.0000419 DB - Crossref KW - ADCIRC KW - HWind KW - Generalized asymmetric Holland model (GAHM) KW - unified wave interface coupled model (UWIN-CM) ER - TY - JOUR TI - Seismic performance of reinforced concrete filled steel tube drilled shafts with inground plastic hinges AU - Aguirre, D.A. AU - Kowalsky, M.J. AU - Nau, J.M. AU - Gabr, M. AU - Lucier, G. T2 - Engineering Structures AB - The seismic performance of reinforced concrete-filled steel tube (RCFST) drilled shafts, also known as RCFST pile-columns, was examined based on experimental tests conducted on twelve half-scale RCFST specimens at the soil-structure interaction facility at the North Carolina State University, Constructed Facilities Laboratory (NCSU-CFL). The specimens consisted of steel tubes with diameter-to-thickness (D/t) ratios ranging from 48 to 95 that were filled with reinforced concrete. Spirally welded steel tubes with outer diameters (D) of 12″ (305 mm) and 12–3/4″ (324 mm) were utilized. The specimens were tested with aboveground-to-diameter (La/D) ratios of 5.5 and 7.5, and they were embedded 14′ (4270 mm) into poorly graded sand (SP). Different levels of soil stiffness were induced in the sand by using a soil-sandwich approach, which allowed for modifying the soil stiffness profile by means of applying a surcharge on the soil surface. Cyclic lateral load was applied by a 100-kip (445 kN), 70-in. (1780 mm) stroke hydraulic actuator, supported on a braced steel frame, and pin-connected to the pile-column head ensuring that the plastic hinge developed below ground. The failure mechanism was controlled by the tensile strain in the steel tube and it was caused by a combination of tube local buckling and tube fracture. First, tube local buckling developed outward at the extreme compression fiber of the section. Tube fracture then occurred in the section with the largest buckle and it extended around about half of the section perimeter. The plastic hinge developed at depths of 2D to 4D. Onset of tube local buckling was observed at higher displacement ductility levels (µ = 3) for specimens using thicker tubes (D/t = 48) than for those using thinner tubes (D/t = 95). The force-displacement response, tensile strain distribution, and hysteretic equivalent viscous damping are discussed in this paper. DA - 2018/6// PY - 2018/6// DO - 10.1016/j.engstruct.2018.03.034 VL - 165 SP - 106-119 J2 - Engineering Structures LA - en OP - SN - 0141-0296 UR - http://dx.doi.org/10.1016/j.engstruct.2018.03.034 DB - Crossref KW - Reinforced concrete KW - Steel tube KW - Drilled shafts KW - Soil-structure interaction ER - TY - JOUR TI - Kenaf addition has mixed effects on process performance of sequencing batch reactors treating municipal wastewater AU - Hurley, Forrest James AU - He, Xia AU - Wang, Ling AU - de los Reyes III, Francis L. T2 - Environmental Science: Water Research & Technology AB - The effects on wastewater treatment due to addition to the mixed liquor of a fine lignocellulosic powder made of dried kenaf were assessed using lab-scale sequencing batch reactors (SBRs) operated for over 200 days. DA - 2018/// PY - 2018/// DO - 10.1039/c7ew00548b VL - 4 IS - 5 SP - 711-720 J2 - Environ. Sci.: Water Res. Technol. LA - en OP - SN - 2053-1400 2053-1419 UR - http://dx.doi.org/10.1039/c7ew00548b DB - Crossref ER - TY - JOUR TI - Formal methods and finite element analysis of hurricane storm surge: A case study in software verification AU - Baugh, John AU - Altuntas, Alper T2 - SCIENCE OF COMPUTER PROGRAMMING AB - Used to predict the effects of hurricane storm surge, ocean circulation models are essential tools for evacuation planning, vulnerability assessment, and infrastructure design. Implemented as numerical solvers that operate on large-scale datasets, these models determine the geographic extent and severity of coastal floods and other impacts. In this study, we look at an ocean circulation model used in production and an extension made to it that offers substantial performance gains. To explore implementation choices and ensure soundness of the extension, we make use of Alloy, a declarative modeling language with tool support and an automatic form of analysis performed within a bounded scope using a SAT solver. Abstractions for relevant parts of the ocean circulation model are presented, including the physical representation of land and seafloor surfaces as a finite element mesh, and an algorithm operating on it that allows for the propagation of overland flows. The approach allows us to draw useful conclusions about implementation choices and guarantees about the extension, in particular that it is equivalence preserving. • An application of formal methods in the context of scientific computing and large-scale physical simulation. • Development of models in Alloy for analyzing relevant parts of an ocean circulation model used in production. • Guarantees about soundness of an extension supported by the approach through experimentation and analysis. DA - 2018/6/15/ PY - 2018/6/15/ DO - 10.1016/j.scico.2017.08.012 VL - 158 SP - 100-121 SN - 1872-7964 UR - https://doi.org/10.1016/j.scico.2017.08.012 KW - Formal methods KW - Model checking KW - Scientific computing KW - Earth and atmospheric sciences ER - TY - JOUR TI - Evaluation of landscape fabric as a solar air heater AU - Poole, Mark R. AU - Shah, Sanjay B. AU - Boyette, Michael D. AU - Grimes, Jesse L. AU - Stikeleather, Larry E. T2 - RENEWABLE ENERGY AB - Solar heating has great potential to displace fossil fuels in agricultural and industrial space heating. The conventional metal transpired solar collectors (mTSC) is highly-efficient but its high cost has impeded its adoption. While the plastic TSC (pTSC) would be less-expensive than the mTSC, it requires perforation. Since a high absorptance, non-woven landscape fabric is widely available and inexpensive, it could be cost-effective solar collector. The landscape fabric collector (fTSC) was compared with mTSC (anodized aluminum) and pTSC for temperature rise (ΔT) and efficiency (η) at two suction velocities (Vs). The mTSC and pTSC had porosity of 1.2% while the fTSC had a porosity of 80%. At 0.047 m/s, the fTSC produced higher average ΔT (by at least 2 °C) and average η (by at least 10%) than the mTSC and pTSC that were similar in performance. At the higher Vs of 0.060 m/s, the fTSC slightly outperformed the mTSC while the pTSC had the lowest ΔT and η. Superior performance of the fTSC was likely due to lower energy losses than the other two collectors as was indicated by its scanning electron microscope images. Modeling the fTSC as a simplified packed bed may be appropriate and challenges have been identified. Practical scale-up suggestions are provided. The fTSC is the least expensive solar air heater for space heating. DA - 2018/11// PY - 2018/11// DO - 10.1016/j.renene.2018.05.045 VL - 127 SP - 998-1003 SN - 0960-1481 KW - Transpired solar collector KW - UTC KW - Landscape fabric KW - Temperature rise KW - Modeling ER - TY - JOUR TI - Evaluation of a novel, low-cost plastic solar air heater for turkey brooding AU - Poole, Mark R. AU - Shah, Sanjay B. AU - Grimes, Jesse L. AU - Boyette, Michael D. AU - Stikeleather, Larry F. T2 - ENERGY FOR SUSTAINABLE DEVELOPMENT AB - Solar heat could displace fossil fuel to reduce energy cost for brooding livestock and poultry. A transpired solar collector (TSC), consisting of a perforated dark-colored metal surface, can provide considerable heating but metal TSCs (mTSCs) are expensive. Since a perforated black plastic sheet will be less-expensive, a plastic TSC (pTSC) was evaluated. The 1.49 m2 pTSC (porosity of 1.2%) supplemented a propane heater in a room housing 240 turkey poults; an adjacent room without a pTSC, with 240 poults was the control. Monitoring was performed over two flocks of poults. A custom-built controller bypassed the pTSC during nighttime or when the room did not require heating to bring in fresh air. The pTSC gave a maximum temperature rise of 25.4 °C at a solar irradiance (I) of 882 W/m2 and suction velocity (Vs) of 0.033 m/s over 15 min. Over 178 h of operation, with an average I of 668 ± 295 W/m2 and average Vs of 0.036 m/s, the pTSC increased air temperature by an average of 8.1 ± 4.2 °C. Probably due to higher ventilation rate and an oversized propane heater, propane use was not reduced in the Test room with the pTSC vs. the Control room. The Test room had lower CO2 and CO concentrations due to higher ventilation, which may have improved turkey performance. The metal TSC gave a slightly higher temperature rise at a lower Vs but the less-expensive pTSC could be a more cost-effective solar air heater that could readily be scaled up for agricultural and other applications in many parts of the world. Scale-up considerations seem feasible and are presented for a 10,000-poult brooder barn. DA - 2018/8// PY - 2018/8// DO - 10.1016/j.esd.2018.04.004 VL - 45 SP - 1-10 SN - 0973-0826 KW - UTC KW - Unglazed KW - Livestock KW - Suction velocity KW - Efficiency KW - Heat exchanger effectiveness ER - TY - CONF TI - Effect of microbial induced carbonate precipitation on the stability of mine tailings AU - Zamani, A. AU - Liu, Q. W. AU - Montoya, B. M. AB - Dams and impoundments are the most conventional method for depositing mine tailings material. Regular operation of the tailings dams often increase the height of the dams, which may make them susceptible to failure. Many existing mine tailings dams are prone to slope failure and require remediation. In this study, microbial induced calcium carbonate precipitation (MICP) is presented as a new method to improve the stability of mine tailings dams against slope failure. MICP also has the potential to improve other deficiencies of the mine tailings material such as surface erosion, static liquefaction, and dynamic liquefaction. In the present study, Slope/W program is used to perform slope stability analysis and observe the effect of MICP on the static slope stability of mine tailings material. The results show an increase in the slope stability after biocementation. The level of improvement in the factor of safety against slope failure depends on the level of treatment. C2 - 2018/// C3 - Ifcee 2018: case histories and lessons learned DA - 2018/// DO - 10.1061/9780784481615.024 SP - 291-300 M1 - 298 ER - TY - JOUR TI - Conjunctive Management of Surface Water and Groundwater Resources under Drought Conditions Using a Fully Coupled Hydrological Model AU - Seo, S. B. AU - Mahinthakumar, G. AU - Sankarasubramanian, A. AU - Kumar, M. T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - A conjunctive management model has been developed to obtain optimal allocation of surface water and groundwater under different constraints during a drought. Two simulation models—a fully distributed hydrologic model and a reservoir simulation model—were incorporated in an optimization formulation using a simulation-optimization approach with response functions. The model was tested for the Haw River Basin located in North Carolina. A fully distributed hydrologic model, penn state integrated hydrologic model (PIHM), was used to compute simultaneous depletions in streamflow and groundwater level under pumping. A reservoir simulation model was then incorporated within the optimization framework to determine the optimal allocation of surface water and groundwater resources by minimizing reservoir deficit. A new groundwater sustainability constraint, recovery time for groundwater levels, was introduced in the conjunctive management model. Incorporating the reservoir simulation model within the optimization model resulted in reduced reservoir deficits. Moreover, the recovery time constraint will allow decision makers to evaluate the trade-off between maximizing water availability and preserving groundwater sustainability during a drought. It is envisioned that the management model proposed in this study is a step toward sustainable groundwater withdrawal during a drought. DA - 2018/9// PY - 2018/9// DO - 10.1061/(asce)wr.1943-5452.0000978 VL - 144 IS - 9 SP - SN - 1943-5452 ER - TY - JOUR TI - The decay of engineered wood products and paper excavated from landfills in Australia AU - Ximenes, Fabiano A. AU - Cowie, Annette L. AU - Barlaz, Morton A. T2 - WASTE MANAGEMENT AB - Large volumes of engineered wood products (EWPs) and paper are routinely placed in landfills in Australia, where they are assumed to decay. However, the extent of decay for EWPs is not well-known. This study reports carbon loss from EWPs and paper buried in landfills in Sydney, Brisbane and Cairns in Australia, located in temperate, subtropical and tropical climates, respectively. The influence of pulp type (mechanical and chemical) and landfill type (municipal solid waste - MSW and construction and demolition - C&D) on decay levels were investigated. Carbon loss for EWPs ranged from 0.6 to 9.0%; though there is some uncertainty in these values due to limitations associated with sourcing appropriate controls. Carbon loss for paper products ranged from 0 to 58.9%. Papers produced from predominantly mechanical pulps generally had lower levels of decay than those produced via chemical or partly chemical processes. Typically, decay levels for paper products were highest for the tropical Cairns landfill, suggesting that climate may be a significant factor to be considered when estimating emissions from paper in landfills. For EWPs, regardless of the landfill type and climate, carbon losses were low, confirming results from previous laboratory studies. Lower carbon losses were observed for EWP and paper excavated from the Sydney C&D landfill, compared with the Sydney MSW landfill, confirming the hypothesis that conditions in C&D landfills are less favourable for decay. These results have implications for greenhouse gas inventory estimations, as carbon losses for EWPs were lower than the commonly assumed values of 23% (US EPA) and 50% (Intergovernmental Panel on Climate Change). For paper types, we suggest that separate decay factors should be used for papers dominated by mechanical pulp and those produced from mostly chemical pulps, and also for papers buried in tropical or more temperate climates. DA - 2018/4// PY - 2018/4// DO - 10.1016/j.wasman.2017.11.035 VL - 74 SP - 312-322 SN - 1879-2456 KW - Landfill KW - Paper KW - Engineered wood products KW - Carbon KW - Decay ER - TY - JOUR TI - Spray injection patching for pothole repair using 100 percent reclaimed asphalt pavement AU - Kwon, Bong Ju AU - Kim, Dahae AU - Rhee, Suk Keun AU - Kim, Y. Richard T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Pothole repair of asphalt pavements is one of the most commonly performed roadway maintenance operations, and it is costly. Reclaimed asphalt pavement (RAP) has become an increasingly attractive material for pothole repair due to its economic and environmental advantages. This study investigated the performance of spray injection patching materials for pothole repair that utilize 100 percent RAP and compared the results to the performance of patching materials made with virgin aggregate. This study was designed to investigate how well different patching products resist critical types of distresses that are observed in the field and typically require patching. The primary characteristics examined in the study include stability, adhesion, moisture susceptibility, and durability of the patching material. The performance of various combinations of materials was observed in laboratory tests to determine the most cost-effective and best-performing patch material. The results show that the material’s performance depended on the type of aggregate and emulsion used in the mixtures. The results also indicate that the mixtures that contained RAP had good stability and adhesion properties compared to the mixtures made with virgin aggregate. This research proved the feasibility and advantages of using RAP for spray injection pothole repair. DA - 2018/3/30/ PY - 2018/3/30/ DO - 10.1016/j.conbuildmat.2018.01.145 VL - 166 SP - 445-451 SN - 1879-0526 KW - Pothole repair KW - Spray injection patching KW - Emulsions KW - Reclaimed asphalt pavement (RAP) KW - And laboratory testing ER - TY - JOUR TI - Observation and modeling of the evolution of an ephemeral storm-induced inlet: Pea Island Breach, North Carolina, USA AU - Velasquez Montoya, Liliana AU - Sciaudone, Elizabeth J. AU - Mitasova, Helena AU - Overton, Margery F. T2 - Continental Shelf Research AB - The Outer Banks of North Carolina is a wave-dominated barrier island system that has experienced the opening and closure of numerous inlets in the last four centuries. The most recent of those inlets formed after the breaching of Pea Island during Hurricane Irene in 2011. The Pea Island Breach experienced a rapid evolution including episodic curvature of the main channel, rotation of the ebb channel, shoaling, widening by Hurricane Sandy in 2012, and finally closing before the summer of 2013. Studying the life cycle of Pea Island Breach contributes to understanding the behavior of ephemeral inlets in breaching-prone regions. This topic has gained relevance due to rising sea levels, a phenomenon that increases the chances of ephemeral inlet formation during extreme events. This study explores the spatiotemporal effects of tides, waves, and storms on flow velocities and morphology of the breach by means of remotely sensed data, geospatial metrics, and a numerical model. The combined use of observations and results from modeling experiments allowed building a conceptual model to explain the life cycle of Pea Island Breach. Wave seasonality dominated the morphological evolution of the inlet by controlling the magnitude and direction of the longshore current that continuously built transient spits at both sides of the breach. Sensitivity analysis to external forcings indicates that ocean waves can modify water levels and velocities in the back barrier. Sound-side storm surge regulates overall growth rate, duration, and decay of peak water levels entering the inlet during extreme events. DA - 2018/3// PY - 2018/3// DO - 10.1016/j.csr.2018.02.002 VL - 156 SP - 55-69 J2 - Continental Shelf Research LA - en OP - SN - 0278-4343 UR - http://dx.doi.org/10.1016/j.csr.2018.02.002 DB - Crossref KW - Coastal morphodynamics KW - Outer Banks KW - Numerical modeling KW - Barrier island breaching KW - Aerial photography KW - Albemarle-Pamlico Sound KW - Inlet dynamics ER - TY - JOUR TI - Investigating the Cost-Benefit Trade-Off of Additional Planning Using Parade Game Simulation AU - Abbasian-Hosseini, S. Alireza AU - Liu, Min AU - Howell, Gregery T2 - JOURNAL OF MANAGEMENT IN ENGINEERING DA - 2018/3// PY - 2018/3// DO - 10.1061/(asce)me.1943-5479.0000580 VL - 34 IS - 2 SP - SN - 1943-5479 KW - Work-plan reliability KW - Variability KW - Variation KW - Construction trade KW - Parade Game KW - Dice Game KW - Workflow ER - TY - JOUR TI - Comparison of Three Retaining Wall Condition Assessment Rating Systems AU - Gabr, Mohammed A. AU - Rasdorf, William AU - Findley, Daniel J. AU - Butler, Cedrick J. AU - Bert, Steven A. T2 - JOURNAL OF INFRASTRUCTURE SYSTEMS AB - In general, the nature of permanent earth retaining structures (ERSs) in highway engineering is well suited to the concept of asset management as a valuable tool for operational efficiency and cost control. Earth retaining structure failures can be detrimental to the roadway and the surroundings, and may pose potential hazards to the safety of the public. Work in this paper utilized field survey results from 11 ERSs to illustrate the disadvantages of using a numerical rating system that relies on a single average number, and the applicability of the alternative system presented herein. The ERSs evaluated include mechanically stabilized earth (MSE), soil nail, anchored, gravity, and cantilever earth retaining wall types. Results indicated that the use of a single-value numerical rating can mask deficiencies in ERS elements that are critical to the stability and function of the ERS system. In addition, the identification of specific elements in distress is not apparent when using such an approach. An alternative two-part rating system provides a summary rating that articulates both the condition of the ERS and identifies potential problems with specific ERS elements. As transportation agencies attempt to align with Moving Ahead for Progress in the 21st Century Act (MAP-21), a two-part condition rating system is recommended to better execute an ERS asset management program and integrate it into a systemwide plan. DA - 2018/3// PY - 2018/3// DO - 10.1061/(asce)is.1943-555x.0000403 VL - 24 IS - 1 SP - SN - 1943-555X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85032731264&partnerID=MN8TOARS KW - Earth retaining structures KW - Infrastructure asset management KW - Retaining wall inventory KW - Asset inventory KW - Data collection KW - Rating system KW - Condition assessment ER - TY - JOUR TI - Benefit of Cooperation among Subcontractors in Performing High-Reliable Planning AU - Javanmardi, Ashtad AU - Abbasian-Hosseini, S. Alireza AU - Liu, Min AU - Hsiang, Simon M. T2 - JOURNAL OF MANAGEMENT IN ENGINEERING AB - As construction projects get larger and more complex, subcontractors can benefit from cooperation and by forming an alliance, such as partnering. Previous studies have discussed the benefit of cooperation or partnering among subcontractors and between them and other project stakeholders. However, there has been limited research to quantify the benefit of cooperation among subcontractors in performing high-reliable planning (HRP). Therefore, the purpose of this paper is to quantify the benefit of cooperation among subcontractors in increasing their planning reliability at an operational level. Although HRP reduces the variability in a production system that significantly benefits the downstream subcontractors, it requires every subcontractor to put more time, cost, and effort into the planning stage, which may not be cost-effective for upstream subcontractors. To model the described situation, a simulation model (built by simulation software) was integrated with a cost model that identifies the relationship between cost and work-plan reliability (WPR) level. By utilizing different benefit-allocation models and evaluating their solutions, the paper demonstrates that a contribution-based benefit-allocation (CBBA) model using a game theory framework can provide the most acceptable and incentivizing solutions for the benefit-allocation problem. This study contributes to the body of knowledge in lean construction by quantifying the benefit of subcontractors’ cooperation in increasing their planning reliability. DA - 2018/3// PY - 2018/3// DO - 10.1061/(asce)me.1943-5479.0000578 VL - 34 IS - 2 SP - SN - 1943-5479 KW - Subcontractors KW - Cooperation KW - Benefit allocation KW - Work-plan reliability KW - Game theory KW - Simulation modeling KW - Lean construction ER - TY - JOUR TI - An Agent-based Modeling Framework for Assessing the Public Health Protection of Water Advisories AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman AU - Lindell, Michael K. T2 - Water Resources Management DA - 2018/2/2/ PY - 2018/2/2/ DO - 10.1007/s11269-018-1916-6 VL - 32 IS - 6 SP - 2033-2059 J2 - Water Resour Manage LA - en OP - SN - 0920-4741 1573-1650 UR - http://dx.doi.org/10.1007/s11269-018-1916-6 DB - Crossref KW - Water distribution network KW - Contamination KW - Complex adaptive system KW - Agent-based modeling KW - News media KW - Broadcast warning KW - Water notification KW - Risk perception ER - TY - JOUR TI - The effects of accelerated Freeze-Thaw conditioning on CFRP strengthened concrete with pre-existing bond defects AU - Mabry, N. J. AU - Seracino, R. AU - Peters, K. J. T2 - Construction and Building Materials AB - Despite demonstrated success in both the laboratory and in the field, significant questions remain unanswered regarding the durability of Carbon Fiber Reinforced Polymer (CFRP) for strengthened concrete members. Little is known about the impact of pre-existing bond defects when subjected to harsh environmental conditions. The results from a study observing the performance of 18 small-scale CFRP-to-concrete pull test specimens is presented herein. Half of the sample set was stored in ambient laboratory conditions while the remaining sample set was subjected to 50 freeze–thaw cycles. Repeated for each condition were 3 specimens prepared without any intentional bond defects and 3 specimens containing 645 mm2 Teflon inserts, for comparison purposes. It was found that, not only did the freeze–thaw conditioning reduce the debonding capacity of the externally bonded CFRP, but that the presence of defects resulted in a greater reduction in debonding capacity following the environmental conditioning, when compared to specimens exposed to ambient conditions only. Nondestructive evaluation of the bonded interface was also performed by using Pulse Phase Thermography (PPT). DA - 2018/// PY - 2018/// DO - 10.1016/j.conbuildmat.2017.12.017 VL - 163 SP - 286-295 ER - TY - JOUR TI - Monthly hydroclimatology of the continental United States AU - Petersen, Thomas AU - Devineni, Naresh AU - Sankarasubramanian, A. T2 - ADVANCES IN WATER RESOURCES AB - Physical/semi-empirical models that do not require any calibration are of paramount need for estimating hydrological fluxes for ungauged sites. We develop semi-empirical models for estimating the mean and variance of the monthly streamflow based on Taylor Series approximation of a lumped physically based water balance model. The proposed models require mean and variance of monthly precipitation and potential evapotranspiration, co-variability of precipitation and potential evapotranspiration and regionally calibrated catchment retention sensitivity, atmospheric moisture uptake sensitivity, groundwater-partitioning factor, and the maximum soil moisture holding capacity parameters. Estimates of mean and variance of monthly streamflow using the semi-empirical equations are compared with the observed estimates for 1373 catchments in the continental United States. Analyses show that the proposed models explain the spatial variability in monthly moments for basins in lower elevations. A regionalization of parameters for each water resources region show good agreement between observed moments and model estimated moments during January, February, March and April for mean and all months except May and June for variance. Thus, the proposed relationships could be employed for understanding and estimating the monthly hydroclimatology of ungauged basins using regional parameters. DA - 2018/4// PY - 2018/4// DO - 10.1016/j.advwatres.2018.02.010 VL - 114 SP - 180-195 SN - 1872-9657 KW - Hydroclimatology KW - Prediction in ungauged basins KW - Physical water balance model KW - Monthly moments ER - TY - JOUR TI - Modeling the sediment dynamics in the gulf of Uraba colombian Caribbean sea AU - Escobar, Carlos A. AU - Velasquez-Montoya, Liliana T2 - OCEAN ENGINEERING AB - The potential of the gulf of Urabá to hold a multi-purpose port motivated a sediment dynamics study to describe the seasonal sediment concentration patterns in this tropical region. Challenges addressed in this study include a complex three-dimensional flow pattern in a tropical estuary and the lack of in-situ measurements. To overcome such challenges, this study completed: (i) Measurements of suspended sediment concentrations during two climatic seasons and an extreme event (2010–2011); (ii) Definition of boundary conditions from global databases; (iii) Qualitative analysis of sediment concentrations from satellite imagery; and (iv) integration of the previously mentioned steps to build a process-based 3D sediment transport model. Seasonal patterns of suspended sediment concentrations were identified and corroborated by the agreement between model results, satellite imagery and field measurements. During the calm rainy season, the Atrato River turbid plume extends northward and dominates the sediment dynamics in the gulf. On the other hand, during the dry season and extreme events, bed transport is enhanced and the river's plume and the littoral drift shift southwards. DA - 2018/1/1/ PY - 2018/1/1/ DO - 10.1016/j.oceaneng.2017.10.055 VL - 147 SP - 476-487 SN - 1873-5258 KW - Sediment transport model KW - Atrato River plume KW - Delft3D KW - Data scarcity KW - Estuarine dynamics ER - TY - JOUR TI - Influence of geometry and fiber properties on rupture strain of cylindrical FRP jackets under internal ICE pressure AU - Sadeghian, Pedram AU - Seracino, Rudolf AU - Das, Baishali AU - Lucier, Gregory T2 - COMPOSITE STRUCTURES AB - This paper presents an study on the rupture strain of cylindrical fiber-reinforced polymer (FRP) jackets under internal ice pressure. A total of 45 cylindrical FRP jackets were prepared using three unidirectional carbon, glass, and basalt fabrics in three different internal diameters, namely 60, 114, and 216 mm, and one-, two-, and three-plies. Three jackets for each combination were typically tested and the average hoop rupture strains were obtained and compared to the rupture strain of flat coupons in the form of a strain efficiency factor. It was found that the strain efficiency factor ranged from 0.53 to 1.05 with an average of 0.77. A new analytical model was also developed based on the bi-axial state of stress in a cylindrical FRP jacket to obtain the rupture strain and strain efficiency factor of the FRP jacket using a closed-form solution. The model engaged four major parameters, namely: diameter, thickness, axial/transverse strength ratio, and Poisson’s ratio of the FRP jacket. The two latter parameters were eliminated after a parametric study to propose a simplified formula. The analytical and simplified models predicted the experimental strain efficiency factors with an average error of −3.4% and −4.6%, respectively. DA - 2018/5/15/ PY - 2018/5/15/ DO - 10.1016/j.compstruct.2018.02.077 VL - 192 SP - 173-183 SN - 1879-1085 UR - https://doi.org/10.1016/j.compstruct.2018.02.077 KW - Strain efficiency KW - Fiber-reinforced polymer KW - Bi-axial stress KW - Confinement KW - Rupture ER - TY - JOUR TI - Impact of solution composition on the resistance of ion exchange membranes AU - Zhu, Shan AU - Kingsbury, Ryan S. AU - Call, Douglas F. AU - Coronell, Orlando T2 - JOURNAL OF MEMBRANE SCIENCE AB - Resistance to ion transport in ion exchange membranes (IEMs) is detrimental to the performance of IEM-based processes. In this work we measured the resistance of representative IEMs, i.e. one cation (CEM) and one anion (AEM) exchange membrane, in 15 single-salt solutions using electrochemical impedance spectroscopy. Resistance was sensitive to solute identity only in the case of the CEM for which it depended on the counter-ion identity; the resistance of the CEM was mostly insensitive to the co-ion identity, and the resistance of the AEM was mostly insensitive to both the counter-ion and co-ion identity. For all solutes, membrane resistance decreased sharply with increasing solution concentration below 0.1 M, and remained approximately constant above 0.1 M. An empirical mathematical model comprising a concentration-dependent term and a concentration-independent term successfully described membrane resistance as a function of solution concentration. The model builds on that previously proposed by Galama et al. (JMS 467 (2014), 279–291). We found that for both membranes, the concentration-dependent and concentration-independent terms of the resistance increased with increasing counter-ion hydration free energy. This was rationalized as the energy barrier to counter-ions having to shed/reorient water molecules of hydration, due to steric effects, when permeating the membranes. Also for both membranes, the concentration-dependent term of the resistance generally had a non-linear relationship with salt concentration. This result suggests that the concentration-dependent term is not attributable to bulk solution, and that there is a degree of randomness to the interconnectedness between the different membrane regions that contribute to ionic resistance. Our findings improve the understanding of the relationships between electrolyte properties and IEM resistance, and provide tools for assessing IEM resistance. This improved understanding is critical to establishing a complete IEM resistance theory and to evaluating new applications for IEMs. DA - 2018/5/15/ PY - 2018/5/15/ DO - 10.1016/j.memsci.2018.02.050 VL - 554 SP - 39-47 SN - 1873-3123 KW - Ion exchange membranes KW - Electrodialysis KW - Reverse electrodialysis KW - Hydration free energy KW - Membrane resistance 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 - 2018/// PY - 2018/// DO - 10.1080/19386362.2016.1272751 VL - 12 IS - 3 SP - 284-292 SN - 1939-7879 KW - Proof roll KW - Subgrade KW - Stabilization KW - FEM KW - DCP ER - TY - JOUR TI - Comparison of real-world and certification emission rates for light duty gasoline vehicles AU - Khan, Tanzila AU - Frey, H. Christopher T2 - SCIENCE OF THE TOTAL ENVIRONMENT AB - U.S. light duty vehicles are subject to the U.S. Environmental Protection Agency (EPA) emission standards. Emission compliance is determined by certification testing of selected emissions from representative vehicles on standard driving cycles using chassis dynamometers. Test results are also used in many emission inventories. The dynamometer based emission rates are adjusted to provide the certification levels (CL), which must be lower than the standards for compliance. Although standard driving cycles are based on specific observations of real-world driving, they are not necessarily real-world representative. A systematic comparison of the real-world emission rates of U.S. light duty gasoline vehicles (LDGVs) versus CL, and emission standards has not been previously reported. The purpose of this work is to compare regulatory limits (both CLs and emission standards) and the real-world emissions of LDGVs. The sensitivity of the comparisons to cold start emission was assessed. Portable Emission Measurement Systems (PEMS) were used to measure hot stabilized exhaust emissions of 122 LDGVs on a specified 110 mile test route. Cold start emissions were measured with PEMS for a selected vehicle sample of 32 vehicles. Emissions were measured for carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx). For each vehicle, a Vehicle Specific Power (VSP) modal emission rate model was developed. The VSP modal rates were weighted by the standard driving cycles and real-world driving cycles to estimate the respective cycle average emission rates (CAERs). Measured vehicles were matched with certification test vehicles for comparison. For systematic trends in comparison, vehicles were classified into four groups based on the Tier 1 and Tier 2 emission regulation, and the vehicle type such as passenger car and passenger truck. Depending on the cycle-pollutant and the vehicle groups, hot stabilized CAERs are on average either statistically significantly higher than or significantly not different from the CLs, with the exception of CO on the US06 cycle, for which real-world rates are lower than CLs. Compared to the emission standards, hot stabilized CAERs are on average significantly lower. However, comparisons of CAERs and standards are sensitive to cold start emissions. For some combinations of pollutants and vehicle groups, cold start inclusive CAERs are higher than the corresponding CLs and as high as the standards. The CLs, which are based on standard driving cycles, tend to underestimate real-world emission rates. Therefore, emission inventory estimates using certification test results are potentially underestimated. DA - 2018/5/1/ PY - 2018/5/1/ DO - 10.1016/j.scitotenv.2017.10.286 VL - 622 SP - 790-800 SN - 1879-1026 UR - https://doi.org/10.1016/j.scitotenv.2017.10.286 KW - Certification tests KW - Emission standards KW - PEMS KW - Chassis dynamometer KW - Driving cycles KW - Cold start emissions ER - TY - JOUR TI - Performance of a coupled transpired solar collector-phase change material-based thermal energy storage system AU - Poole, Mark R. AU - Shah, Sanjay B. AU - Boyette, Michael D. AU - Stikeleather, Larry F. AU - Cleveland, Tommy T2 - ENERGY AND BUILDINGS AB - The transpired solar collector (TSC) is a low-cost technology for heating ventilation air for mainly for use in industrial and agricultural applications. Storing the excess energy generated during daytime in phase change material (PCM) could improve the economics of using TSCs. Since energy generated for storage could be increased by using a two-stage TSC (with a glazing) vs. a one-stage TSC, first, the thermal performance of the two configurations were compared. Then, performance of the PCM-based thermal energy storage (TES) unit coupled to a TSC was evaluated. At a suction velocity of 0.023 m/s, the one-stage TSC produced a 2 °C higher temperature rise and 8% higher efficiency than the two-stage TSC. The one-stage TSC was coupled to a TES unit packed with 80 kg of salt-hydrate type PCM (specific energy of ∼185 kJ/kg). When evaluated at four airflow rates, the TES unit stored between 76 and 107% of its theoretical heat storage capacity and provided tempered air 4 °C warmer than ambient air during nighttime. While residual energy (for daytime heating) increased with airflow rate, energy charged or discharged was unaffected. Over a week, the TSC-TEC stored 34% of the total useful energy produced for nighttime use, with a potential to displace 1.35 kg of liquefied natural gas. Replacing the expensive metal TSC with a perforated plastic TSC and a simpler TES design would improve the economics of storing solar energy for use after sundown. DA - 2018/2/15/ PY - 2018/2/15/ DO - 10.1016/j.enbuild.2017.12.027 VL - 161 SP - 72-79 SN - 1872-6178 KW - Ventilation KW - Tempering KW - COP KW - Two-stage KW - One-stage KW - UTC ER - TY - JOUR TI - Patterns and drivers of fish extirpations in rivers of the American Southwest and Southeast AU - Kominoski, John S. AU - Ruhi, Albert AU - Hagler, Megan M. AU - Petersen, Kelly AU - Sabo, John L. AU - Sinha, Tushar AU - Sankarasubramanian, Arumugam AU - Olden, Julian D. T2 - GLOBAL CHANGE BIOLOGY AB - Effective conservation of freshwater biodiversity requires spatially explicit investigations of how dams and hydroclimatic alterations among climate regions may interact to drive species to extinction. We investigated how dams and hydroclimatic alterations interact with species ecological and life history traits to influence past extirpation probabilities of native freshwater fishes in the Upper and Lower Colorado River (CR), Alabama-Coosa-Tallapoosa (ACT), and Apalachicola-Chattahoochee-Flint (ACF) basins. Using long-term discharge data for continuously gaged streams and rivers, we quantified streamflow anomalies (i.e., departure "expected" streamflow) at the sub-basin scale over the past half-century. Next, we related extirpation probabilities of native fishes in both regions to streamflow anomalies, river basin characteristics, species traits, and non-native species richness using binomial logistic regression. Sub-basin extirpations in the Southwest (n = 95 Upper CR, n = 130 Lower CR) were highest in lowland mainstem rivers impacted by large dams and in desert springs. Dampened flow seasonality, increased longevity (i.e., delayed reproduction), and decreased fish egg sizes (i.e., lower parental care) were related to elevated fish extirpation probability in the Southwest. Sub-basin extirpations in the Southeast (ACT n = 46, ACF n = 22) were most prevalent in upland rivers, with flow dependency, greater age and length at maturity, isolation by dams, and greater distance upstream. Our results confirm that dams are an overriding driver of native fish species losses, irrespective of basin-wide differences in native or non-native species richness. Dams and hydrologic alterations interact with species traits to influence community disassembly, and very high extirpation risks in the Southeast are due to interactions between high dam density and species restricted ranges. Given global surges in dam building and retrofitting, increased extirpation risks should be expected unless management strategies that balance flow regulation with ecological outcomes are widely implemented. DA - 2018/3// PY - 2018/3// DO - 10.1111/gcb.13940 VL - 24 IS - 3 SP - 1175-1185 SN - 1365-2486 KW - biodiversity loss KW - dams KW - flow regime KW - global change KW - imperiled species ER - TY - JOUR TI - Multi-objective optimization applied for designing hybrid power generation systems in isolated networks AU - Fonseca, Marcelo Nunes AU - Pamplona, Edson de Oliveira AU - Queiroz, Anderson Rodrigo AU - Mello Valerio, Victor Eduardo AU - Aquila, Giancarlo AU - Silva, Saulo Ribeiro T2 - SOLAR ENERGY AB - The use of hybrid power generation systems is an attractive alternative to conventional fossil fuel generation since they may assist in mitigating the emission of gases that are harmful to the atmosphere when using clean and renewable sources of energy. However, finding the ideal configuration for the installation of a hybrid system composed of solar photovoltaic (PV)-diesel generation is a complex task. In this sense, the objective of this study is to develop an approach to select the optimal configuration of hybrid power generation systems for isolated regions by means of combining the techniques of Mixing Design of Experiments, Normal Boundary Intersection and analysis of super efficiency using Data Envelopment Analysis. The proposed approach is applied to a set of four isolated regions in the northern region of Brazil, more specifically in the state of Amazonas. The results show that for each region a different configuration is selected but with large shares of diesel generation at first. On the other hand, all these cases represent points in the Pareto frontier that are the most inefficient due to the high volume of CO2 emissions. From the application of the proposed approach, significant CO2 emission reductions are obtained by selecting the optimal configurations represented as the most efficient points in the Pareto frontier. Our results show that due to conflicting characteristics of the selected objectives, the installation of such hybrid power generation systems produces an increase in LCOE, mainly related to the high costs of the batteries, although less accentuated than the reductions in emissions. DA - 2018/2// PY - 2018/2// DO - 10.1016/j.solener.2017.12.046 VL - 161 SP - 207-219 SN - 0038-092X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85039797533&partnerID=MN8TOARS KW - Hybrid systems KW - Photovoltaic-diesel KW - Normal Boundary Intersection KW - Multi-objective optimization ER - TY - JOUR TI - Mass accommodation coefficients of fresh and aged biomass-burning emissions AU - Sinha, Aditya AU - Saleh, Rawad AU - Robinson, Ellis S. AU - Ahern, Adam T. AU - Tkacik, Daniel S. AU - Presto, Albert A. AU - Sullivan, Ryan C. AU - Robinson, Allen L. AU - Donahue, Neil M. T2 - AEROSOL SCIENCE AND TECHNOLOGY AB - Most chemical transport models treat the partitioning of semi-volatile organic compounds (SVOCs) with the assumption of instantaneous thermodynamic equilibrium. However, the mass accommodation coefficients, α, of biomass-burning organic aerosol (BBOA) are largely unconstrained. During the FLAME-IV campaign, we thermally perturbed aged and fresh BBOA with a variable residence time thermodenuder and measured the resulting change in particle mass concentration to restore equilibrium. We used this equilibration profile to retrieve an effective α for components of BBOA that dictated this profile and found that the mass accommodation coefficients lie within the range 0.1 ≪ α ⩽ 1. A simple plume dilution model shows a maximum of only a 7% difference between a dynamical and an instantaneous equilibrium partitioning model using our best-estimate value for α. This supports continued use of the equilibrium assumption to treat partitioning of biomass-burning emissions in chemical-transport models.Copyright © 2018 American Association for Aerosol Research DA - 2018/// PY - 2018/// DO - 10.1080/02786826.2017.1413488 VL - 52 IS - 3 SP - 300-309 SN - 1521-7388 KW - Ilona Riipinen ER - TY - JOUR TI - Effect of Distraction on Hazard Recognition and Safety Risk Perception AU - Namian, Mostafa AU - Albert, Alex AU - Feng, Jing T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Both hazard recognition and safety risk perception are fundamental to effective safety management. When construction hazards remain unrecognized or the associated safety risk remains unperceived, the likelihood of human errors and injuries increases. Unfortunately, recent studies have shown that a large number of construction hazards remain unrecognized in typical workplaces. Likewise, past research has demonstrated that safety risk is widely underestimated in construction. Therefore, to improve safety performance, a proper understanding of factors that influence hazard recognition and safety risk perception is vital. Toward achieving this goal, the objective of the current study is to evaluate the effect of distractions—which are ubiquitous in construction environments—on the hazard recognition performance and safety risk perception of workers. The study goals are accomplished through an experimental effort involving 70 construction workers representing various specialty trades. The workers were randomly assigned to a distracted or undistracted condition, and their hazard recognition performance and safety risk perception levels were measured using construction case images. The study findings revealed that the distracted workers recognized a smaller proportion of hazards compared with undistracted workers. However, there were no significant differences in the level of perceived safety risk between the two groups. A closer examination of the data revealed that the safety risk perception levels for the undistracted workers are positively related to their hazard recognition performance. In other words, when undistracted workers recognize a larger proportion of hazards, they also perceive higher levels of safety risk. However, no such relationship was observed for the distracted workers, suggesting that the perceived risk was unrelated to or not dependent on their hazard recognition performance. The findings suggest that workplace distractions can adversely affect hazard recognition, safety risk perception, and safety performance. Given that constuction workers are already exposed to numerous distractors in typical workplaces, contractors seeking to introduce emerging technologies such as drones, mobile devices, and smart robots must be cognizant of their potential distracting effects. The current study represents the first empirical effort investigating the effect of workplace distraction on construction hazard recognition and safety risk perception. DA - 2018/4// PY - 2018/4// DO - 10.1061/(asce)co.1943-7862.0001459 VL - 144 IS - 4 SP - SN - 1943-7862 KW - Construction safety KW - Hazard recognition KW - Hazard identification KW - Safety risk perception KW - Distraction KW - Injury prevention ER - TY - JOUR TI - Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway AU - Saha, Provat K. AU - Khlystov, Andrey AU - Grieshop, Andrew P. T2 - ATMOSPHERIC CHEMISTRY AND PHYSICS AB - Abstract. We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semi-volatile species (SVOCs) in ultrafine particles decreases with downwind distance, which is consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20–30 % of particle mass as semi-volatile (SVOCs; effective saturation concentration, C∗ ≥ 1µm−3) at 10 m from the road edge, approximately 10 % of particle mass is attributed to SVOCs at 220 m, showing that the particle-phase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle phase increased during winter. Downwind spatial gradients of the less volatile particle fraction (that remaining after heating at 180 °C) were strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a single-particle soot photometer (SP2) at the roadside trailer showed that a large fraction (70–80 %) of BC particles were externally mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the nonvolatile fraction in roadside aerosols is mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that the mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a few hundred meters from the highway. Our analysis indicates that a superposition of volatility distributions measured in laboratory vehicle tests and of background aerosol can be used to represent the observed partitioning of near-road particles. The results from this study show that exposures and impacts of BC and semi-volatile organics-containing particles in a roadside microenvironment may differ across seasons and under changing ambient conditions. DA - 2018/2/14/ PY - 2018/2/14/ DO - 10.5194/acp-18-2139-2018 VL - 18 IS - 3 SP - 2139-2154 SN - 1680-7324 UR - https://doi.org/10.5194/acp-18-2139-2018 ER - TY - JOUR TI - Assessing the impact of the 4CL enzyme complex on the robustness of monolignol biosynthesis using metabolic pathway analysis AU - Naik, Punith AU - Wang, Jack P. AU - Sederoff, Ronald AU - Chiang, Vincent AU - Williams, Cranos AU - Ducoste, Joel J. T2 - PLOS ONE AB - Lignin is a polymer present in the secondary cell walls of all vascular plants. It is a known barrier to pulping and the extraction of high-energy sugars from cellulosic biomass. The challenge faced with predicting outcomes of transgenic plants with reduced lignin is due in part to the presence of unique protein-protein interactions that influence the regulation and metabolic flux in the pathway. Yet, it is unclear why certain plants have evolved to create these protein complexes. In this study, we use mathematical models to investigate the role that the protein complex, formed specifically between Ptr4CL3 and Ptr4CL5 enzymes, have on the monolignol biosynthesis pathway. The role of this Ptr4CL3-Ptr4CL5 enzyme complex on the steady state flux distribution was quantified by performing Monte Carlo simulations. The effect of this complex on the robustness and the homeostatic properties of the pathway were identified by performing sensitivity and stability analyses, respectively. Results from these robustness and stability analyses suggest that the monolignol biosynthetic pathway is resilient to mild perturbations in the presence of the Ptr4CL3-Ptr4CL5 complex. Specifically, the presence of Ptr4CL3-Ptr4CL5 complex increased the stability of the pathway by 22%. The robustness in the pathway is maintained due to the presence of multiple enzyme isoforms as well as the presence of alternative pathways resulting from the presence of the Ptr4CL3-Ptr4CL5 complex. DA - 2018/3/6/ PY - 2018/3/6/ DO - 10.1371/journal.pone.0193896 VL - 13 IS - 3 SP - e0193896 J2 - PLoS ONE LA - en OP - SN - 1932-6203 UR - http://dx.doi.org/10.1371/journal.pone.0193896 DB - Crossref ER - TY - JOUR TI - A High-Throughput Approach for Identification of Nontuberculous Mycobacteria in Drinking Water Reveals Relationship between Water Age and Mycobacterium avium AU - Haig, Sarah-Jane AU - Kotlarz, Nadine AU - LiPuma, John J. AU - Raskin, Lutgarde T2 - MBIO AB - Nontuberculous mycobacteria (NTM) frequently detected in drinking water (DW) include species associated with human infections, as well as species rarely linked to disease. Methods for improved the recovery of NTM DNA and high-throughput identification of NTM are needed for risk assessment of NTM infection through DW exposure. In this study, different methods of recovering bacterial DNA from DW were compared, revealing that a phenol-chloroform DNA extraction method yielded two to four times as much total DNA and eight times as much NTM DNA as two commercial DNA extraction kits. This method, combined with high-throughput, single-molecule real-time sequencing of NTM rpoB genes, allowed the identification of NTM to the species, subspecies, and (in some cases) strain levels. This approach was applied to DW samples collected from 15 households serviced by a chloraminated distribution system, with homes located in areas representing short (<24 h) and long (>24 h) distribution system residence times. Multivariate statistical analysis revealed that greater water age (i.e., combined distribution system residence time and home plumbing stagnation time) was associated with a greater relative abundance of Mycobacterium avium subsp. avium, one of the most prevalent NTM causing infections in humans. DW from homes closer to the treatment plant (with a shorter water age) contained more diverse NTM species, including Mycobacterium abscessus and Mycobacterium chelonae Overall, our approach allows NTM identification to the species and subspecies levels and can be used in future studies to assess the risk of waterborne infection by providing insight into the similarity between environmental and infection-associated NTM.IMPORTANCE An extraction method for improved recovery of DNA from nontuberculous mycobacteria (NTM), combined with single-molecule real-time sequencing (PacBio) of NTM rpoB genes, was used for high-throughput characterization of NTM species and in some cases strains in drinking water (DW). The extraction procedure recovered, on average, eight times as much NTM DNA and three times as much total DNA from DW as two widely used commercial DNA extraction kits. The combined DNA extraction and sequencing approach allowed high-throughput screening of DW samples to identify NTM, revealing that the relative abundance of Mycobacterium avium subsp. avium increased with water age. Furthermore, the two-step barcoding approach developed as part of the PacBio sequencing method makes this procedure highly adaptable, allowing it to be used for other target genes and species. DA - 2018/// PY - 2018/// DO - 10.1128/mbio.02354-17 VL - 9 IS - 1 SP - SN - 2150-7511 KW - DNA extraction KW - drinking water KW - Mycobacterium avium KW - NTM KW - PacBio KW - premise plumbing ER - TY - JOUR TI - Spatial and temporal characteristics of elevated temperatures in municipal solid waste landfills, Navid H. Jafari, Timothy D. Stark, and Todd Thalhamer, Waste Management, 2017, Vol. 59, p. 286-301 AU - Barlaz, Morton A. AU - Benson, Craig H. AU - Castaldi, Marco AU - Luettich, Scott T2 - WASTE MANAGEMENT AB - Heat generation in municipal solid waste landfills is reviewed with a focus on extraction heat management strategy. Numerical analysis was conducted to investigate the feasibility of a vertical heat extraction system and effects of system configuration on overall performance. The modeling indicated that the influence of the extraction system on landfill temperatures is greatest near central depths of the landfill with less influence at the cover and liner locations. Temperature-depth profiles exhibited concave shapes demonstrating preferential heat extraction from central depths and return of the waste temperatures to reference conditions at great radial distance. For extraction system parameters, fluid velocity affected heat extraction more than pipe diameter; for landfill operational conditions, waste height affected heat extraction more than waste placement rate. For a fluid velocity of 0.3 m/s (threshold for turbulent flow), pipe diameter of 25.4 mm, waste height of 30 m, and waste placement rate of 20 m/year, the heat extraction rate was 59.5 MJ/m3 and the total amount of heat extracted was 561 GJ with 10 m radius of influence of the extraction well. Thermally coupled gas generation analysis indicated that regulating temperatures at 35 °C resulted in significant increases in landfill gas energy (on the order of twofold) and decreasing the time to reach biological stabilization by 70–77%. Due to the transition of operation to a geothermal system at the end of heat production lifetime of landfills, heat extraction systems provide long-term sustainable alternative energy sources with appreciable energy production in comparison to other renewable technologies. DA - 2018/1// PY - 2018/1// DO - 10.1016/j.wasman.2017.05.050 VL - 71 SP - 244-245 SN - 0956-053X ER - TY - JOUR TI - Shear strengthening of steel plates using small-diameter CFRP strands AU - Kazem, Hamid AU - Rizkalla, Sami AU - Kobayashi, Akira T2 - COMPOSITE STRUCTURES AB - This paper presents the results of a comprehensive research program, including experimental and analytical studies, to examine the use of small-diameter CFRP strands for shear strengthening of steel structures and bridges. The experimental program examined the effectiveness of the proposed strengthening system to increase the shear capacity of steel plates subjected to pure shear stresses using a unique test set up. A nonlinear finite element analysis (FEA), calibrated the experimental results, was used to study parameters which were not included in the experiments. Research findings indicated that the proposed system is effective for shear strengthening of steel structures and eliminated the typical debonding failure commonly observed by CFRP laminates. DA - 2018/1/15/ PY - 2018/1/15/ DO - 10.1016/j.compstruct.2017.09.094 VL - 184 SP - 78-91 SN - 1879-1085 KW - Small-diameter CFRP KW - Debonding KW - Finite element analysis (FEA) KW - Steel KW - Shear ER - TY - JOUR TI - Performance and damage evolution of plain and fibre-reinforced segmental concrete pipelines subjected to transverse permanent ground displacement AU - Pour-Ghaz, Mohammad AU - Wilson, Jacob AU - Spragg, Robert AU - Nadukuru, Srinivasa S. AU - Kim, Junhee AU - Sean M. O'Connor, AU - Byrne, Edward M. AU - Sigurdardottir, Dorotea H. AU - Yao, Yao AU - Michalowski, Radoslaw L. AU - Lynch, Jerome P. AU - Green, Russell A. AU - Bradshaw, Aaron S. AU - Glisic, Branko AU - Weiss, Jason T2 - STRUCTURE AND INFRASTRUCTURE ENGINEERING AB - This paper presents the results of three full-scale experiments performed on segmental concrete pipelines subjected to permanent ground displacement. The first pipeline was made of reinforced concrete pipes and the second pipeline was made of steel fibre-reinforced concrete pipes. The third pipeline was made of a combination of fibre-reinforced and reinforced concrete pipes. An array of sensing techniques was used to assess the damage evolution in pipelines and their overall performance. Three stages of damage were observed. In the first stage, damage was concentrated in the joints near the fault line. In the second stage, the damage occurred in all joints along the pipeline. While in the first two stages damage was mainly concentrated at the bell and spigot joints of the pipe segments, the third stage of damage was characterised by severe damage and rupture of the body of pipe segments located in the immediate vicinity of the fault line. The modes of failure for the plain and fibre-reinforced concrete pipelines were similar in the first and second stages of damage. However, in the pipeline constructed using both plain and fibre-reinforced concrete pipe segments, the damage was concentrated in the standard reinforced concrete pipe segments. DA - 2018/// PY - 2018/// DO - 10.1080/15732479.2017.1349809 VL - 14 IS - 2 SP - 232-246 SN - 1744-8980 KW - Concrete reinforced KW - damage assessment KW - earthquake engineering KW - pipes & pipelines KW - sensors KW - soil-structure interaction KW - permanent ground displacement ER - TY - JOUR TI - Computationally efficient fragility assessment using equivalent elastic limit state and Bayesian updating AU - Kwag, Shinyoung AU - Gupta, Abhinav T2 - COMPUTERS & STRUCTURES AB - Conventionally, the seismic response of primary structures such as buildings and secondary systems such as piping is evaluated through uncoupled analyses. Many studies have illustrated that the two systems interact in many different ways (mass interaction, non-classical damping, phasing, etc.). An analysis of the coupled system is not only rational but also eliminates the excessive conservatism that exists in an uncoupled analysis. Consequently, fragility assessments based on uncoupled analysis are also incorrect and a coupled analysis must be conducted in such evaluations. However, nonlinear analyses of such complex systems particularly in the context of fragility assessment, which requires a large number of nonlinear analyses, becomes computationally prohibitive. Tadinada and Gupta (2017) presented an equivalent elastic limit state concept with an intent to reduce the computational effort needed in these assessments and yet evaluate the seismic fragility with sufficient accuracy. This paper outlines some of the limitations that have been experienced in the use of originally proposed equivalent limit-state formulation and presents valuable enhancements. The novel contribution of this study is focused on accounting for the effect of uncertainty in nonlinear characteristics and the effect of non-classical damping. Unlike the originally proposed formulation, the proposed formulation also considers the asymmetric variation of the equivalent limit state with respect to tuning ratio. Furthermore, a Bayesian approach is incorporated into the proposed methodology for increasing the accuracy of seismic fragilities in the case of tuned or nearly tuned primary-secondary systems. Numerical examples are used to illustrate that the modified form improves the accuracy for both the tuned and the detuned systems. In summary, the proposed approach provides an efficient framework of seismic fragility assessment and risk evaluation for coupled systems. DA - 2018/2/15/ PY - 2018/2/15/ DO - 10.1016/j.compstruc.2017.11.011 VL - 197 SP - 1-11 SN - 1879-2243 ER - TY - JOUR TI - Clean cooking and the SDGs: Integrated analytical approaches to guide energy interventions for health and environment goals AU - Rosenthal, Joshua AU - Quinn, Ashlinn AU - Grieshop, Andrew P. AU - Pillarisetti, Ajay AU - Glass, Roger I. T2 - ENERGY FOR SUSTAINABLE DEVELOPMENT AB - Development and implementation of clean cooking technology for households in low and middle income countries (LMICs) offer enormous promise to advance at least five Sustainable Development Goals (SDGs): 3. Good health and well-being; 5. Gender equality; 7. Affordable and clean energy; 13. Climate action; 15. Life on land. Programs are being implemented around the world to introduce alternative cooking technologies, and we are well on the way to achieving the goal set by the Global Alliance for Clean Cookstoves to reach 100 million homes with cleaner and more efficient cooking methods by 2020. Despite evidence that household air pollution (HAP) from solid fuel combustion is responsible for 3-4 million early deaths per year, many cookstove programs are motivated and/or financed by climate change mitigation schemes and deploy alternative stoves that use solid fuels such as wood and charcoal. However, recent studies have demonstrated that improved biomass-burning stoves typically only incrementally improve air quality and yield modest or minimal health benefits. Likewise, their contributions to climate change mitigation and other SDGs may be limited. Evidence indicates that cleaner fuels, such as liquefied petroleum gas (LPG), ethanol and biogas, offer greater potential benefits not only to health, but also greater progress towards climate goals and other relevant SDGs. We present a modeled estimate of these potential gains for a diverse group of 40 LMICs. Our model suggests that cookstove programs using LPG stoves and fuel will yield greater reductions in both Disability Adjusted Life Years and Global Warming Commitment in these countries than those using improved biomass stoves. Cost and infrastructure requirements for clean fuels such as LPG are widely recognized constraints. In view of these constraints we present an analytical method to simultaneously consider health and climate needs at the national level for the same 40 countries in the context of estimated LPG expansion potentials. Comparative analyses integrating priorities across SDGs at the national and regional levels may guide more practical and effective household energy development choices going forward. DA - 2018/2// PY - 2018/2// DO - 10.1016/j.esd.2017.11.003 VL - 42 SP - 152-159 SN - 2352-4669 ER - TY - JOUR TI - Characterization of air pollutant concentrations, fleet emission factors, and dispersion near a North Carolina interstate freeway across two seasons AU - Saha, Provat K. AU - Khlystov, Andrey AU - Snyder, Michelle G. AU - Grieshop, Andrew P. T2 - ATMOSPHERIC ENVIRONMENT AB - We present field measurement data and modeling of multiple traffic-related air pollutants during two seasons at a site adjoining Interstate 40, near Durham, North Carolina. We analyze spatial-temporal and seasonal trends and fleet-average pollutant emission factors and use our data to evaluate a line source dispersion model. Month-long measurement campaigns were performed in summer 2015 and winter 2016. Data were collected at a fixed near-road site located within 10 m from the highway edge, an upwind background site and, under favorable meteorological conditions, along downwind perpendicular transects. Measurements included the size distribution, chemical composition, and volatility of submicron particles, black carbon (BC), nitrogen oxides (NOx), meteorological conditions and traffic activity data. Results show strong seasonal and diurnal differences in spatial distribution of traffic sourced pollutants. A strong signature of vehicle emissions was observed within 100–150 m from the highway edge with significantly higher concentrations during morning. Substantially higher concentrations and less-sharp near-road gradients were observed in winter for many species. Season-specific fleet-average fuel-based emission factors for NO, NOx, BC, and particle number (PN) were derived based on up- and down-wind roadside measurements. The campaign-average NOx and PN emission factors were 20% and 300% higher in winter than summer, respectively. These results suggest that the combined effect of higher emissions and their slower downwind dispersion in winter dictate the observed higher downwind concentrations and wider highway influence zone in winter for several species. Finally, measurements of traffic data, emission factors, and pollutant concentrations were integrated to evaluate a line source dispersion model (R-LINE). The dispersion model captured the general trends in the spatial and temporal patterns in near-road concentrations. However, there was a tendency for the model to under-predict concentrations near the road in the mornings and over-predict concentrations in the evenings. DA - 2018/3// PY - 2018/3// DO - 10.1016/j.atmosenv.2018.01.019 VL - 177 SP - 143-153 SN - 1873-2844 UR - https://doi.org/10.1016/j.atmosenv.2018.01.019 KW - Vehicle emissions KW - Ultrafine particles KW - Gas-particle partitioning KW - Dispersion modeling ER - TY - JOUR TI - Biofilms in Full-Scale Drinking Water Ozone Contactors Contribute Viable Bacteria to Ozonated Water AU - Kotlarz, Nadine AU - Rockey, Nicole AU - Olson, Terese M. AU - Haig, Sarah-Jane AU - Sanford, Larry AU - LiPuma, John J. AU - Raskin, Lutgarde T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Concentrations of viable microbial cells were monitored using culture-based and culture-independent methods across multichamber ozone contactors in a full-scale drinking water treatment plant. Membrane-intact and culturable cell concentrations in ozone contactor effluents ranged from 1200 to 3750 cells/mL and from 200 to 3850 colony forming units/mL, respectively. Viable cell concentrations decreased significantly in the first ozone contact chamber, but rose, even as ozone exposure increased, in subsequent chambers. Our results implicate microbial detachment from biofilms on contactor surfaces, and from biomass present within lime softening sediments in a hydraulic dead zone, as a possible reason for increasing cell concentrations in water samples from sequential ozone chambers. Biofilm community structures on baffle walls upstream and downstream from the dead zone were significantly different from each other (p = 0.017). The biofilms downstream of the dead zone contained a significantly (p = 0.036) higher relative abundance of bacteria of the genera Mycobacterium and Legionella than the upstream biofilms. These results have important implications as the effluent from ozone contactors is often treated further in biologically active filters and bacteria in ozonated water continuously seed filter microbial communities. DA - 2018/3/6/ PY - 2018/3/6/ DO - 10.1021/acs.est.7b04212 VL - 52 IS - 5 SP - 2618-2628 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.7b04212 ER - TY - JOUR TI - Analysis of the wind average speed in different Brazilian states using the nested GR & R measurement system AU - Aquila, Giancarlo AU - Peruchi, Rogerio Santana AU - Rotela Junior, Paulo AU - Souza Rocha, Luiz Celio AU - Queiroz, Anderson Rodrigo AU - Pamplona, Edson de Oliveira AU - Balestrassi, Pedro Paulo T2 - MEASUREMENT AB - Brazil presents remarkable potential for wind power generation. This study aims to evaluate the behavior of wind average speed at the four major wind energy-producing states. The main contribution of this research is to use the NGR&R study (Nested Gage Repeatability & Reproducibility), generally applied on manufacturing quality management. Wind average speeds were collected for each month in four states, between the years of 2012 and 2015. Seasonality impact, measurements recurrence over the years and difference between states on wind average speed were assessed in this research. Time series, boxplot and control charts have been used to investigate not only wind average speed between months and states, but also range variation for each state by month. Study results show that the impact of these three factors is statistically significant and that the different location of these states presents the most relevant impact to wind mean speed variation in the country. DA - 2018/2// PY - 2018/2// DO - 10.1016/j.measurement.2017.10.048 VL - 115 SP - 217-222 SN - 1873-412X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85032342123&partnerID=MN8TOARS KW - Wind power KW - Wind speed KW - Measurement system analysis KW - NGR & R ER - TY - JOUR TI - Probabilistic risk assessment based model validation method using Bayesian network AU - Kwag, Shinyoung AU - Gupta, Abhinav AU - Dinh, Nam T2 - RELIABILITY ENGINEERING & SYSTEM SAFETY AB - Past few decades have seen a rapid growth in the availability of computational power and that induces continually reducing cost of simulation. This rapidly changing scenario together with availability of high precision and large-scale experimental data has enabled development of high fidelity simulation tools capable of simulating multi-physics multi-scale phenomena. At the same time, there has been an increased emphasis on developing strategies for verification and validation of such high fidelity simulation tools. The problem is more pronounced in cases where it is not possible to collect experimental data or field measurements on a large-scale or full scale system performance. This is particularly true in case of systems such as nuclear power plants subjected to external hazards such as earthquakes or flooding. In such cases, engineers rely solely on simulation tools but struggle to establish the credibility of the system level simulations. In practice, validation approaches rely heavily on expert elicitation. There is an increasing need of a quantitative approach for validation of high fidelity simulations that is comprehensive, consistent, and effective. A validation approach should be able to consider uncertainties due to incomplete knowledge and randomness in the system's performance as well as in the characterization of external hazard. A new approach to validation is presented in this paper that uses a probabilistic index as a degree of validation and propagates it through the system using the performance-based probabilistic risk assessment (PRA) framework. Unlike traditional PRA approaches, it utilizes the power of Bayesian statistic to account for non-Boolean relationships and correlations among events at various levels of a network representation of the system. Bayesian updating facilitates evaluation of updated validation information as additional data from experimental observations or improved simulations is incorporated. PRA based framework assists in identifying risk-consistent events and critical path for appropriate allocation of resources to improve the validation. DA - 2018/1// PY - 2018/1// DO - 10.1016/j.ress.2017.09.013 VL - 169 SP - 380-393 SN - 1879-0836 ER - TY - JOUR TI - Another Grand Challenge: Diversity in Environmental Engineering AU - Blaney, Lee AU - Perlinger, Judith A. AU - Bartelt-Hunt, Shannon L. AU - Kandiah, Ramanitharan AU - Ducoste, Joel J. T2 - Environmental Engineering Science AB - As efforts to address grand challenges in engineering move forward, one important challenge has been conspicuously absent—improving diversity in science, technology, engineering, and math fields. Previous research has shown that diverse teams perform better in a range of output measures and are better equipped to objectively and creatively evaluate problems. Here, we make the case for including diversity as a critical component of our ability to enable transformative solutions to the grand challenges in environmental engineering. DA - 2018/6// PY - 2018/6// DO - 10.1089/ees.2017.0337 VL - 35 IS - 6 SP - 568-572 J2 - Environmental Engineering Science LA - en OP - SN - 1557-9018 UR - http://dx.doi.org/10.1089/ees.2017.0337 DB - Crossref KW - environmental engineering KW - engineering education KW - demographics KW - gender KW - ethnicity KW - race ER -