TY - JOUR TI - Air pollution at college football games: Developing a methodology for measuring air pollutant exposure in a sport event microenvironment AU - Bunds, K.S. AU - Casper, J.M. AU - Frey, H.C. AU - Barrett, M. T2 - Event Management AB - International organizations such as the United Nations have begun to recognize the connection between sport events and air pollution. However, to date, there has been a dearth of research attempting to measure air pollution at sporting events. To address the lack of research on air pollution at sporting events, in this article we developed a methodology for measuring the air pollution at a college football game utilizing both stationary and mobile monitoring systems. Stationary monitors allowed for the creation of a microenvironment wherein we could examine the overall particulate matter exposure within the stadium and tailgate lot areas. Mobile monitors allowed for the examination of specific causes of spikes in air pollution. We found grills, generators, and cars caused pollutant spikes, which were, at times, over 20 times worse than the recognized levels for moderate air quality. Additionally, while the overall pollution in the microenvironment was elevated, pollutant levels during postgame (i. e., where there is a rush of individuals leaving at the same time) were consistently and considerably higher. Implications for practice and future research include event policy considerations and the application of the methodology across alternative sporting venues/contexts. DA - 2019/// PY - 2019/// DO - 10.3727/152599518X15403853721484 VL - 23 IS - 3 SP - 399-412 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85073696760&partnerID=MN8TOARS ER - TY - CHAP TI - Use of polymer nanocomposites in asphalt binder modification AU - Gulzar, S. AU - Underwood, S. T2 - Advanced Functional Textiles and Polymers: Fabrication, Processing and Applications AB - This chapter contains sections titled: Introduction Background Polymer Nanocomposites Rheological Impacts Suggested Evaluation Method for PNC Modified Asphalt Binders Summary PY - 2019/// DO - 10.1002/9781119605843.ch14 SP - 405-432 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85086007280&partnerID=MN8TOARS ER - TY - JOUR TI - Energy System Planning Considering Renewables and Pumped-storage Power Plants T2 - International Journal of Smart Grid and Sustainable Energy Technologies AB - Renewables will play an important role in the generation for the next decades, but the great problem they face is the intermittency of the natural resource availability, mainly when considering solar and wind generation. In this context, the pumped-storage finds a great opportunity. Its operation consists of two mains mechanisms: to pump water to be stored in an upper reservoir when there is surplus of energy in the system, and to generate as a regular power plant, with the stored water, when there is a lack of energy in the system. This paper presents an introductory with a revision of the world consumption and capacity of 2030 considering the parcel of renewables, and a simulation of several possibilities of the energy mix in various Scenarios. The simulations consider mainly the contribution of pumped-storage hydro. The possible arrangements of construction pumped-storage hydro, costs, and a mathematical model of linear optimization using pumped-storage are analyzed and presented. The developed method is applied to several Scenarios and the conclusions are obtained from that. DA - 2019/// PY - 2019/// DO - 10.36040/IJSGSET.V1I2.206 UR - https://publons.com/wos-op/publon/65805759/ ER - TY - JOUR TI - Motivators for treated wastewater acceptance across developed and developing contexts AU - Rice, J. AU - Stotts, R. AU - Wutich, A. AU - White, D. AU - Maupin, J. AU - Brewis, A. 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 - 2019/// PY - 2019/// DO - 10.2166/washdev.2018.285 VL - 9 IS - 1 SP - 1-6 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85074064934&partnerID=MN8TOARS ER - TY - JOUR TI - Integrated Assessment of Wastewater Reuse, Exposure Risk, and Fish Endocrine Disruption in the Shenandoah River Watershed AU - Barber, Larry B. AU - Rapp, Jennifer L. AU - Kandel, Chintamani AU - Keefe, Steffanie H. AU - Rice, Jacelyn AU - Westerhoff, Paul AU - Bertolatus, David W. AU - Vajda, Alan M. T2 - Environmental Science and Technology AB - Reuse of municipal and industrial wastewater treatment plant (WWTP) effluent is used to augment freshwater supplies globally. The Shenandoah River Watershed (U.S.A.) was selected to conduct on-site exposure experiments to assess endocrine disrupting characteristics of different source waters. This investigation integrates WWTP wastewater reuse modeling, hydrological and chemical characterization, and in vivo endocrine disruption bioassessment to assess contaminant sources, exposure pathways, and biological effects. The percentage of accumulated WWTP effluent in each river reach (ACCWW%) was used to predict environmental concentrations for consumer product chemicals (boron), pharmaceutical compounds (carbamazepine), and steroidal estrogens (estrone, 17-β-estradiol, estriol, and 17-α-ethinylestradiol). Fish endocrine disruption was evaluated using vitellogenin induction in adult male or larval fathead minnows. Water samples were analyzed for >500 inorganic and organic constituents to characterize the complex contaminant mixtures. Municipal ACCWW% at drinking water treatment plant surface water intakes ranged from <0.01 to 2.0% under mean-annual streamflow and up to 4.5% under mean-August streamflow. Measured and predicted environmental concentrations resulted in 17-β-estradiol equivalency quotients ranging from 0.002 to 5.0 ng L-1 indicating low-to-moderate risk of fish endocrine disruption. Results from the fish exposure experiments showed low (0.5- to 3.2-fold) vitellogenin induction in adult males. DA - 2019/// PY - 2019/// DO - 10.1021/acs.est.8b05655 VL - 53 IS - 7 SP - 3429-3440 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85063787982&partnerID=MN8TOARS ER - TY - JOUR TI - Cross-cultural knowledge and acceptance of wastewater reclamation and reuse processes across select sites AU - Stotts, R. AU - Rice, J. AU - Wutich, A. AU - Brewis, A. AU - White, D. AU - Maupin, J. T2 - Human Organization AB - Water is in a constant state of circulation and reuse. Most reuse is unplanned, suggesting significant potential for planned reuse. Yet, attempts to implement planned potable reuse of wastewater have often been countered by public resistance. Based mostly on analyses from high-income countries, scholars have argued that educating people on the technical processes of wastewater reuse will lead to increased public acceptance. Our research explores the relationship between knowledge of wastewater treatment technology and acceptance of direct potable wastewater reuse and examines the perspectives of residents of lower and middle countries in context with, and in comparison to, residents of wealthier countries. Using data collected through semi-structured interviews with residents in community sites in Guatemala, Fiji, New Zealand, and Spain, our analysis highlights how little knowledge of wastewater treatment technology exists and that such knowledge has little bearing on wastewater reuse acceptability. Rather, cultural factors like trust are likely key. We propose that efforts to increase acceptance of potable wastewater reuse needs to be focused on explicitly cultural factors like trust more so than public education in the strict sense. DA - 2019/// PY - 2019/// DO - 10.17730/0018-7259.78.4.311 VL - 78 IS - 4 SP - 311-324 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85074841328&partnerID=MN8TOARS ER - TY - CONF TI - Erosion Reduction near Spillway Foundations using Bio-Cementation AU - Do, J. AU - Montoya, B. AU - Gabr, M. T2 - Dam Safety 2019 C2 - 2019/// C3 - Proceedings from Dam Safety 2019, Association of State Dam Safety Officials (ASDSO) CY - Orlando, FL DA - 2019/// PY - 2019/// ER - TY - CONF TI - Rapid Drawdown Analysis using the Deformation-based Limit State Approach AU - Jadid, R. AU - Montoya, B.M. AU - Gabr, M. T2 - Dam Safety 2019 C2 - 2019/// C3 - Proceedings from Dam Safety 2019, Association of State Dam Safety Officials (ASDSO) DA - 2019/// PY - 2019/// ER - TY - JOUR TI - Scheme for Field Implementation of Microbially Induced Carbonate Precipitation adjacent to Pile Foundation System AU - Do, J. AU - Montoya, B.M. AU - Gabr, M.A. T2 - ASCE Geotechnical Special Publication DA - 2019/// PY - 2019/// VL - 309 SP - 280–288 ER - TY - CONF TI - Breakthrough of Benzene Soluble Phase in Subsurface Domain with Concrete Utility Pipe AU - Alhomair, S. AU - Hosseini, P. AU - Gabr, M. AU - Pour-Ghaz, M. AU - Knappe, D. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering C2 - 2019/// C3 - Geo-Congress 2019: Geoenvironmental Engineering and Sustainability DA - 2019/// PY - 2019/// SP - 115–124 SN - 9780784482148 ER - TY - ER - TY - ER - TY - CONF TI - Factors Affecting the Kinetics of Urea Hydrolysis via Sporoscarcina pasteurii AU - Safavizadeh, Shahin AU - Montoya, Brina M. AU - Gabr, Mohammed A. AU - Knappe, Detlef R. U. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering AB - Microbial induced carbonate precipitation (MICP) is a bio-mediated approach to improve engineering properties of granular materials. Cell population, substrate concentration, alkalinity, and temperature are the main factors controlling urea hydrolysis rate in the MICP process. In this study, the effects of initial substrate (urea) concentration and cell population on the rate of urea hydrolysis were evaluated using electrical conductivity as a monitoring method. For this purpose, a correlation between electrical conductivity and hydrolyzed urea concentration was derived from a batch test program. Various initial substrate concentrations and cell populations were selected in another batch test program to evaluate their contribution to the urea hydrolysis rate. Increasing both initial substrate concentration and cell population accelerated the rate as discussed in detail in this paper. Finally, a simplified column testing program was completed to demonstrate the effectiveness of electrical conductivity as a monitoring parameter during MICP treatment. C2 - 2019/3/21/ C3 - Geo-Congress 2019 DA - 2019/3/21/ DO - 10.1061/9780784482148.011 PB - American Society of Civil Engineers UR - http://dx.doi.org/10.1061/9780784482148.011 ER - TY - JOUR TI - Utilising demand response for distribution service restoration to achieve grid resiliency against natural disasters AU - Hafiz, F. AU - Chen, B. AU - Chen, C. AU - De Queiroz, A.R. AU - Husain, I. T2 - IET Generation, Transmission and Distribution AB - The increased frequency of power outages due to natural disasters in recent years has highlighted the urgency of enhancing distribution grid resilience. The effective distribution service restoration (DSR) is an important measure for a resilient distribution grid. In this work, the authors demonstrate that DSR can be significantly improved by leveraging the flexibility provided by the inclusion of demand response (DR). The authors propose a framework for this by considering integrated control of household-level flexible appliances to vary the load demand at the distribution-grid level to improve DSR. The overall framework of the proposed system is modelled as a three-step method considering three optimization problems to (i) calculate feasible controllable aggregated load range for each bus, (ii) determine candidate buses to perform DR and their target load demand, and (iii) maintain the load level in each house through home energy management during the DSR, considering uncertainties in load and solar generation sequentially. The optimization problems are formulated as linear programming, mixed-integer linear programming, and multistage stochastic programming (solved using the stochastic dual dynamic programming) models. Case studies performed in the IEEE 123-node test feeder show improvements in resilience in terms of energy restored compared to the restoration process without DR. DA - 2019/// PY - 2019/// DO - 10.1049/iet-gtd.2018.6866 VL - 13 IS - 14 SP - 2942-2950 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85069476402&partnerID=MN8TOARS ER - TY - JOUR TI - Repurposing an Energy System Optimization Model for Seasonal Power Generation Planning AU - Queiroz, A.R. AU - Mulcahy, D. AU - Sankarasubramanian, A. AU - Deane, J.P. AU - Mahinthakumar, G. AU - Lu, N. AU - DeCarolis, J.F. T2 - arXiv DA - 2019/// PY - 2019/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85095310995&partnerID=MN8TOARS ER - TY - CONF TI - Real-time Stochastic Optimization of Energy Storage Management using Rolling Horizon Forecasts for Residential PV Applications AU - Hafiz, F. AU - Awal, M.A. AU - De Queiroz, A.R. AU - Husain, I. AB - In this paper, an energy management method for a residential PV-storage hybrid system composed of a solar photovoltaic (PV) generation and a battery energy storage (BES) is formulated as an offline optimization model concurrent with a real-time rule-based controller. Existing offline energy management approaches for day ahead scheduling of BES generally suffers from energy loss in real-time due to the stochastic nature of load and solar generation. On the other hand, typical online algorithms do not offer optimal solutions for minimizing electricity purchase costs to the owners. To overcome such limitations, we propose an integrated framework where optimization is performed in receding horizon utilizing the forecasted load and solar generation profiles from long short term memory (LSTM) in rolling horizon to reduce daily electricity purchase costs. The optimization model is formulated as a multi-stage stochastic program where we use the stochastic dual dynamic programming (SDDP) algorithm in the receding horizon to update the optimal set-point for BES dispatch at a fixed interval. To prevent loss of energy during optimal solution update instants, we propose a rule-based controller beneath the optimization layer in finer time resolution at the power electronics converter control level. The proposed framework is evaluated using a realtime controller-hardware-in-the-Ioop (CHIL) test platform in an Opal-RT simulator. The proposed real-time method reduces the net electricity purchase cost relative to other existing energy management methods. C2 - 2019/// C3 - 2019 IEEE Industry Applications Society Annual Meeting, IAS 2019 DA - 2019/// DO - 10.1109/IAS.2019.8912315 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85076767755&partnerID=MN8TOARS ER - TY - CONF TI - Efficiency analysis for performance evaluation of electricity distribution companies AU - Santos, L.C.B. AU - Medeiros, G.O.S. AU - Lima, L.M.M. AU - Queiroz, A.R. AU - Alvares, J.E. AU - Gomes, R. AU - Barbosa, M.A. AU - Marangon Lima, J.W. C2 - 2019/// C3 - ECOS 2019 - Proceedings of the 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems DA - 2019/// SP - 1569-1581 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85079664013&partnerID=MN8TOARS ER - TY - JOUR TI - Coordinated Control of PEV and PV-Based Storages in Residential Systems under Generation and Load Uncertainties AU - Hafiz, F. AU - De Queiroz, A.R. AU - Husain, I. T2 - IEEE Transactions on Industry Applications AB - Energy storage deployment in residential and commercial applications is an attractive proposition for ensuring 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. For optimal energy management, PV generation and load demand uncertainties need to be considered when designing a control method for the PV-based storage system. Another resource available at the residential level is the plug-in electric vehicle (PEV) which also has bi-directional power flow capability. The charging and discharging routines of the PEV can be controlled to help reduce the energy drawn from the power grid during peak hours. 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 algorithm is employed to optimize the charge/discharge profiles of PV-based storage and PEV storage to minimize the daily household electricity purchase cost from the grid. Simulation analysis shows the advantage of the coordinated control compared to other control strategies. DA - 2019/// PY - 2019/// DO - 10.1109/TIA.2019.2929711 VL - 55 IS - 6 SP - 5524-5532 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85075497159&partnerID=MN8TOARS ER - TY - JOUR TI - US Energy-Related Greenhouse Gas Emissions in the Absence of Federal Climate Policy AU - Eshraghi, H. AU - Queiroz, A.R.D. AU - DeCarolis, J.F. T2 - arXiv DA - 2019/// PY - 2019/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85094022064&partnerID=MN8TOARS ER - TY - JOUR TI - Evaluation of manufacturers strategies to obtain high-efficient induction motors AU - Bortoni, E.C. AU - Bernardes, J.V. AU - Silva, P.V.V. AU - Faria, V.A.D. AU - Vieira, P.A.V. T2 - Sustainable Energy Technologies and Assessments AB - This paper presents a study on how manufacturers are working to comply with the minimum energy performance standards in three-phase squirrel-cage induction-motors. One of the possibilities is to reduce the stator and rotor resistances, and to increase the magnetizing branch resistance. A method to obtain the parameters of the equivalent circuit of the induction motor from the catalog data sheet is shown. A new method to separate the short-circuit reactance in stator and rotor components, based on start-up and breakdown torques, is presented. The variation in rotor parameters as a function of the slip is conveniently accounted for. The proposed methodology is applied to several motors from different manufacturers of significant influence in the European market. The main parameters that affect losses and energy efficiency of motors are compared, establishing an idea on how each of these manufacturers acts to meet energy efficiency requirements. DA - 2019/// PY - 2019/// DO - 10.1016/j.seta.2018.12.022 VL - 31 SP - 221-227 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85058820204&partnerID=MN8TOARS KW - Induction motors KW - Equivalent circuit KW - Parameter estimation KW - Energy efficiency KW - MEPS ER - TY - JOUR TI - Hydropower revenues under the threat of climate change in Brazil AU - Queiroz, Anderson Rodrigo AU - Faria, Victor A.D. AU - Lima, Luana M.M. AU - Lima, José W.M. T2 - Renewable Energy AB - This work analyzes the impacts of climate change in the revenues of hydropower plants. One important input for designing and evaluating investment opportunities in hydropower is the water inflows historical data. Unfortunately, the use of such information alone may not project well the future power generation due to the influence of climate change in the water inflow patterns. This paper introduces spatio-temporal information of the future climate into the operational planning of the Brazilian hydropower system. Global climate models from IPCC are considered along with downscaled regional climate models. Our results at the individual hydro plant level show the importance of taking into account climate change information when performing hydro generation planning studies. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.renene.2018.10.050 VL - 133 SP - 873-882 UR - http://dx.doi.org/10.1016/j.renene.2018.10.050 KW - Assured energy KW - Hydropower generation KW - Climate change KW - Water-energy nexus KW - Hydro plants revenue ER - TY - CONF TI - Reinforced Concrete Containment Walls Subjected to Combined In-Plane and Out-of-Plane Shear Stresses: Experimental Investigation and Sectional Analysis AU - Proestos, G.T. AU - Bentz, E.C. AU - Collins, M.P. T2 - 25th Conference on Structural Mechanics in Reactor Technology C2 - 2019/8/4/ C3 - Transactions, SMiRT-25: 25th Conference on Structural Mechanics in Reactor Technology CY - Charlotte, North Carolina, USA DA - 2019/8/4/ PY - 2019/8/4/ ER - TY - RPRT TI - Assessment of the Contribution of Input Motion Selection Procedures to Uncertainty in Ground Motion Intensity Measures AU - Cabas, A. AU - Kaklamanos, J. AU - Kottke, A. AU - Chowdhury, I. DA - 2019/// PY - 2019/// M3 - USGS Final Report ER - TY - JOUR TI - Column chromatography approach to determine mobility of fluorotelomer sulfonates and polyfluoroalkyl betaines AU - Zhi, Y. AU - Liu, J. T2 - Science of the Total Environment AB - Betaine-based polyfluoroalkyl surfactants are major perfluoroalkyl and polyfluoroalkyl surfactants (PFASs) found in many aqueous film-forming foams (AFFF) impacted sites, while the transport behavior (i.e., mobility and adsorption) of PFAS-based betaines in groundwater and natural geosorbents interfaces remains unclear. To fill the knowledge gap, partitioning between of 15 AFFF-relevant PFASs, including 3 fluorotelomer sulfonates (FTSAs) and 3 polyfluoroalkyl betaines, and a model soil organic matter (SOM) were systematically assessed using a modified column chromatography approach. Results show that the retention of FTSAs (perfluoroalkyl chain-length of 4, 6, and 8) to SOM are similar to that of corresponding legacy perfluoroalkyl sulfonic acids (PFSAs) with the same chain length; FTSAs also respond to changes in solution chemistry similarly as PFSAs. At a solution pH of 5.9, based on the equilibrium speciation of the betaine-PFASs together with the experimental observations, the predominance of the neutral species over zwitterions gives rise to the relatively higher retention of polyfluoroalkyl betaines than perfluoroalkyl carboxylic acids (PFCAs) of equivalent chain-length. Sorption edges (minimal and maximal logKoc values over a defined pH range) determined for three polyfluoroalkyl betaines are: 1.90-3.81 for perfluorooctaneamide betaine (PFOAB), 2.03-2.65 for perfluoroctane sulfonamide betaine (PFOSB), and < 3.04 for 6:2 fluorotelomer sulfonamide betaine (6:2 FTAB). Moreover, the increase in pH reduces the sorption of all PFASs to SOM. Increasing calcium ion (concentration ranges from 0.5 to 50 mM) has enhanced the sorption of anionic PFASs to SOM but decreased the sorption of the polyfluoroalkyl betaines. These findings are expected to improve the ability to anticipate and predict the possible subsurface locations (i.e., predominantly in groundwater or sorbed to soil) of both novel and legacy PFASs. DA - 2019/// PY - 2019/// DO - 10.1016/j.scitotenv.2019.05.149 VL - 683 SP - 480-488 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85066039064&partnerID=MN8TOARS KW - Soil organic matter (SOM) KW - Zwitterionic PFASs KW - Polyfluoroalkyl betaines KW - Adsorption KW - Distribution coefficients (log K-d) KW - Organic carbon normalized distribution coefficient (log K-oc) ER - TY - JOUR TI - Variational Assimilation of Streamflow Observations in Improving Monthly Streamflow Forecasting AU - Mazrooei, A. AU - Sankarasubramanian, A. AU - Wood, A.W. T2 - Hydrology and Earth System Sciences AB - Abstract. Uncertainties associated with the initial conditions (e.g. soil moisture content) of a hydrologic model have been recognized as one of the main sources of errors in hydrologic predictions, specifically over a rainfall-runoff regime. Apart from the recent advances in Data Assimilation (DA) for improving hydrologic predictions, this study explores variational assimilation (VAR) of gauge-measured daily streamflow data for updating initial state of soil moisture content of Variable Infiltration Capacity (VIC) Land Surface Model (LSM) in order to improve streamflow simulations as well as monthly streamflow forecasting. The study is conducted for the Tar River basin in North Carolina over 20-year period (1991–2010). The role of two critical parameters of VAR DA – the frequency of DA application and the length of assimilation window – in determining the skill of DA-improved streamflow predictions is also assessed. We found that correcting VIC model's initial conditions using a 7-day assimilation window results in the highest improvement in the skill of streamflow predictions quantified by Kling-Gupta Efficiency (KGE) and Nash-Sutcliffe Efficiency (NSE) metrics. In addition, the potential gain from VAR DA framework is quantified and compared under two 1-month ahead streamflow forecasting schemes: 1) deterministic forecasts developed by using ECHAM4.5 GCM 1-month ahead precipitation forecasts and 2) Probabilistic forecasts from Ensemble Streamflow Prediction (ESP) approach. This study also examines the persistence of the DA impact in the monthly predictions by quantifying the enhanced accuracy in daily flows over extending forecast lead time blocks. Analyses show that the the corrected initial state conditions continually enhance the 7–8 days ahead predictions, but after that the errors in forcings dominate the DA effects. Still, the overall impact of VAR DA in monthly streamflow forecasting is positive. DA - 2019/// PY - 2019/// DO - 10.5194/hess-2019-288 M3 - preprint ER - TY - SOUND TI - Full of Gold (FOG): Identifying value added initiatives for Fats, oil, and Grease waste streams AU - Ducoste, J.J. DA - 2019/8/19/ PY - 2019/8/19/ ER - TY - SOUND TI - Evaluation of alternative light models for estimating light attenuation during microalgal cultivation AU - Karam, A. AU - de los Reyes, F., III AU - Ducoste, J. DA - 2019/5/14/ PY - 2019/5/14/ ER - TY - CONF TI - It’s Time to Disrupt this Industry AU - Gallimore, E. AU - Mabry, N. AU - Ducoste, J. T2 - Water Environment Federation (WEF) Interactive Knowledge Exchange (IKE) video submission, Water Environment Federation Technology Conference C2 - 2019/// CY - Chicago, IL DA - 2019/// PY - 2019/9/21/ ER - TY - SOUND TI - Designing Efficient Grease Abatement Systems AU - Ducoste, J.J. DA - 2019/3/2/ PY - 2019/3/2/ ER - TY - SOUND TI - Tips on Successfully Navigating Graduate School AU - Ducoste, J.J. DA - 2019/10/18/ PY - 2019/10/18/ ER - TY - CONF TI - Effect of RAP Amount on the Aging Susceptibility of Asphalt Mixtures AU - Mocelin, D. AU - Saleh, N.F. AU - Castorena, C. AU - Kim, Y.R. T2 - North Carolina Department of Transportation Research and Innovation Summit C2 - 2019/// CY - Greensboro, NC DA - 2019/// PY - 2019/5// ER - TY - JOUR TI - Design, construction, and evaluation of energy-harvesting asphalt pavement systems AU - Saleh, N.F. AU - Zalghout, A.A. AU - Sari Ad Din, S.A. AU - Chehab, G.R. AU - Saad, G.A. T2 - Road Materials and Pavement Design AB - Energy-harvesting pavements, one of which is the Hydronic Asphalt Pavement (HAP) system, have been proven to be both more durable and sustainable than conventional pavement systems. A HAP consists of a system of connected pipes embedded within the asphalt pavement which function to extract or reject heat from/into the pavement via a circulating fluid. Three large-scale systems were designed and constructed in the field: a control section, a regular HAP section, and a section containing a HAP coupled to a horizontal ground heat exchanger (GCHAP). The field data showed that neither the HAP section nor the GCHAP section were able to substantially decrease the pavement surface temperature. However, both GCHAP and HAP were able to decrease the asphalt temperature at a depth of 2.5 cm below the surface by a magnitude of around 10°C. Another key finding of this study shows that increasing the conductivity of a flexible pavement asphalt layer, rather than increasing the conductivity of the embedded pipes, significantly enhances the effectiveness of the HAP system. DA - 2019/// PY - 2019/// DO - 10.1080/14680629.2018.1564352 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060025429&partnerID=MN8TOARS KW - hydronic KW - HAP KW - energy-harvesting KW - geothermal KW - asphalt KW - pavement ER - TY - RPRT TI - Fatigue or Not Fatigue, That is the Question AU - Underwood, Shane AU - Braham, Andrew DA - 2019/5// PY - 2019/5// DO - 10.13140/RG.2.2.13898.41921/1 M3 - White paper UR - http://rgdoi.net/10.13140/RG.2.2.13898.41921/1 ER - TY - SOUND TI - Solving the Plastic Waste Problem AU - Barlaz, M.A. DA - 2019/// PY - 2019/// ER - TY - CONF TI - Per- and Polyfluoroalkyl Substances (PFAS) in Landfill Leachate and Municipal Wastewater and Occurrence in Drinking Water Sources AU - Thelusmond, J.R. AU - Barlaz, M.A. T2 - SETAC C2 - 2019/// CY - Toronto, Canada DA - 2019/// PY - 2019/11/4/ ER - TY - CONF TI - PFAS in Landfill Leachate and Municipal Wastewater AU - Barlaz, M.A. AU - Thelusmond, J.-R. T2 - Environmental Research & Education Foundation (EREF) Summit on PFAS in Leachate C2 - 2019/// CY - Ypsilanti, MI DA - 2019/// PY - 2019/8/14/ ER - TY - CONF TI - Linking Anaerobic Microbial Population Dynamics to Waste Type and Decomposition Stage AU - Barlaz, M.A. AU - Reyes, F.L. AU - Wang, L. AU - Lee, E. T2 - Environmental Research and Education Foundation (EREF) Summit on Municipal Solid Waste (MSW) Organics C2 - 2019/// CY - Burlingame, CA DA - 2019/// PY - 2019/7/17/ ER - TY - CONF TI - The presence of poly- and perfluoroalkyl substances (PFAS) in landfill leachate AU - Barlaz, M.A. T2 - Solid Waste Association of North America, North Carolina Chapter (NC SWANA) Spring Conference C2 - 2019/// CY - Wrightsville Beach, NC DA - 2019/// PY - 2019/3/5/ ER - TY - JOUR TI - Influence of viscoelastic properties of cold recycled asphalt mixtures on pavement response by means of temperature instrumentation AU - Kuchiishi, André Kazuo AU - Santos Antão, Camila Christine AU - Vasconcelos, Kamilla AU - Bernucci, Liedi Legi Bariani T2 - Road Materials and Pavement Design AB - Cold recycled asphalt mixtures (CRAMs) have been widely used in pavement construction and rehabilitation of base courses. Some studies describe it as granular materials, without stiffness dependency regarding temperature or frequency variation, while other researches state that it resembles a viscoelastic material. This indicates that the CRAMs mechanical behaviour is not fully understood. In the present study, dynamic modulus tests were conducted with CRAMs samples and the master curves suggested a viscoelastic behaviour for this type of mixture. The dynamic modulus results were used as input data in 3D-Move Analysis software and the pavement structure was simulated at different temperature conditions based on temperature instrumentation data collected from the field. It was found that the temperature dependency of CRAMs’ stiffness influences pavement mechanical behaviour. Besides, the relative stiffness between CRAMs and AC layers plays a major role in pavement response for varying temperatures. Therefore, CRAM's viscoelastic properties cannot be neglected. DA - 2019/7/31/ PY - 2019/7/31/ DO - 10.1080/14680629.2019.1633781 VL - 20 IS - sup2 SP - S710-S724 UR - https://doi.org/10.1080/14680629.2019.1633781 KW - asphalt emulsion mixture KW - foamed asphalt mixture KW - dynamic modulus KW - experimental test sections KW - pavement simulation ER - TY - JOUR TI - Effect of temperature on the fatigue behavior of asphalt binder T2 - Applied Rheology AB - Abstract Asphalt pavement is under different climatic conditions throughout its service life, which means that fatigue cracking does not occur at a specific temperature, but at a temperature range. The main objective of this paper is to evaluate the influence of different temperatures in the fatigue life of two asphalt binders: a non-modified binder (penetration grade 30/45) and a highly polymermodified binder (HPMB). The fatigue resistance characterization was performed by means of a linear amplitude sweep (LAS) test at the temperatures of 10, 15, 20, 25, and 30°C using a dynamic shear rheometer (DSR). From the dynamic shear modulus (|G*|) results, adhesion loss was observed between the binder and the rheometer parallel plate at the lower temperature of 10°C,while at higher temperatures (25 and 30°C) plastic flow was observed rather than fatigue damage. Therefore, considering that the actual test procedure does not specify the testing temperature, the evaluation of failure mechanism is essential to validate test results, because the random selection of test temperature might lead to inconsistent data. DA - 2019/1/1/ PY - 2019/1/1/ DO - 10.1515/arh-2019-0004 UR - http://dx.doi.org/10.1515/arh-2019-0004 KW - Fatigue resistance KW - asphalt binder KW - linear amplitude sweep test KW - temperature ER - TY - JOUR TI - Investigation of the matric suction role on the curing mechanism of foamed asphalt stabilised mixtures AU - Kuchiishi, André Kazuo AU - Santos Antão, Camila Christine AU - Vasconcelos, Kamilla AU - Pires, José AU - Oliveira Araújo, Olga Maria AU - Bernucci, Liedi Legi Bariani AU - Lopes, Ricardo Tadeu T2 - Road Materials and Pavement Design AB - Moisture content is of great importance for foamed asphalt stabilised mixtures, since it influences mixing, compaction, curing process and the structural performance. The curing process, in which water evaporates, is responsible for the increase of the bearing capacity of foamed mixtures. Although different loading resistance mechanisms contribute simultaneously to the layer stiffness, the aim of this research is to evaluate the influence of matric suction in the stiffness of two foamed asphalt mixtures that have been used as base course materials in experimental test sections. Filter paper, X-ray microcomputed tomography and triaxial resilient modulus tests were conducted at four moisture conditions. The filter paper test indicated an increase in the matric suction when water evaporated from the specimen, which was validated by the reduction of the air voids measured with microcomputed tomography. From triaxial resilient modulus and matric suction results, it was observed that although other mechanisms might be dominating the loading resistance of foamed mixtures, the matric suction influences the stiffness of these materials. DA - 2019/4/30/ PY - 2019/4/30/ DO - 10.1080/14680629.2019.1589558 VL - 3 SP - 1-25 UR - https://doi.org/10.1080/14680629.2019.1589558 KW - moisture KW - experimental test section KW - suction pressure KW - X-ray microcomputed tomography KW - triaxial resilient modulus ER - TY - JOUR TI - Assessing Vertical Diffusion and Cyanobacteria Bloom Potential in a Shallow Eutrophic Reservoir AU - Han, Yue AU - Smithheart, Jeremy W. AU - Smyth, Robyn L. AU - Aziz, Tarek N. AU - Obenour, Daniel T2 - LAKE AND RESERVOIR MANAGEMENT AB - Han Y, Smithheart JW, Smyth RL, Aziz TN, Obenour CR. 2019. Assessing vertical diffusion and cyanobacteria bloom potential in a shallow eutrophic reservoir. Lake Reserv Manage. 36:169–185.Harmful blooms of cyanobacteria are an increasing threat to many lakes and reservoirs. While vertical mixing has been shown to be an important control on cyanobacteria dominance in some lakes, the relevance of mixing in relatively shallow turbid systems remains unclear. To explore mixing and its impact on cyanobacteria bloom potential, we leveraged data from a multiyear field campaign of a central North Carolina reservoir where artificial circulators were installed to (1) implement a parsimonious one-dimensional (1D) turbulent diffusion model with an artificial circulation term, (2) introduce a novel multi-objective calibration approach considering both water column temperature and stability, and (3) explore how mixing affects cyanobacteria bloom potential through changes in cyanobacteria light exposure relative to other algal taxa. Our multi-objective calibration approach is shown to realistically simulate both water temperature (R2 = 0.99) and water column stability (R2 = 0.62) throughout the year. Analysis of artificial mixing demonstrates the relative insignificance of the circulator deployment in our study area and suggests that at least eight times the implemented circulation rate would be required to substantially reduce the ability of buoyant cyanobacteria to outcompete other algal taxa for light. Overall, this study demonstrates an efficient and systematic approach for characterizing vertical mixing in lakes and reservoirs, which can be used to assess the viability of artificial circulation prior to deployment. DA - 2019/// PY - 2019/// DO - 10.1080/10402381.2019.1697402 VL - 36 IS - 2 SP - 169–185 KW - Algal bloom KW - artificial mixing KW - cyanobacteria KW - diffusion KW - turbid lake ER - TY - CONF TI - A Geo-processing Tool for co-locating the dependency of critical infrastructure with hydrologic information network AU - Mukhopadhyay, S. AU - Mazrooei, A. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - The Roles of Climate Variability on Runoff at Daily, Monthly, Inter-annual, and Mean Annual Scales AU - Yao, L. AU - Libera, D. AU - Kheimi, M. AU - Arumugam, S. AU - Wang, D. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - What defines a flood? Building shared understanding across differing attributes and definitions of flooding AU - Archfield, S.A. AU - Ryberg, K.R. AU - Blum, A.G. AU - Barth, N.A. AU - Awasthi, C. AU - Li, H. AU - Abeshu, G.W. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Climate-Water-Energy Nexus: An Integrated Modeling Framework to Analyze Water and Power Systems Under a Changing Climate AU - Ford, L. AU - Queiroz, A. AU - DeCarolis, J. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - The role of climate on crop yield per unit area across the contiguous United States AU - Kumar, H. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Using an Integrated Groundwater and Surface Water Model for Understanding the Effects of Climate Change Scenarios on the Food-Energy-Water Nexus AU - Libera, D. AU - Wang, D. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - How Regional Evapotranspiration Fluxes are altered due to Urbanization? AU - Mazrooei, A. AU - Arumugam, S. AU - Wang, D. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - How does flow alteration propagate across a large, highly-regulated basin? Dam attributes, network context, and implications for biodiversity AU - Ruhi, A. AU - Hwang, J. AU - Devineni, N. AU - Mukhopadhyay, S. AU - Kumar, H. AU - Comte, L. AU - Worland, S. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Sustainable Water Management in the Lower Colorado Basin: Influence of Climate and Regulatory Context on the Ability to Meet Human and Environmental Water Needs AU - Tu, T. AU - Arumugam, S. AU - Dong, X. AU - Dyckman, C. AU - Grantham, T. AU - Olson, L.J. AU - Ruddell, B. L. AU - Ulibarri, N. AU - Ruhi, A. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Human and climate variables explain spatio-temporal patterns of streamflow variation across the United States AU - Chalise, D. AU - Arumugam, S. AU - Ruhi, A. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Sustainable Urban Systems: Managing the Urban Multiplex and its Hydrologic Challenges AU - Yeghiazarian, L. AU - Merwede, V. AU - Golden, H.E. AU - Arumugam, S. AU - Welty, C. AU - Bales, J. AU - Cai, X. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Revising Flood-Frequency Curves under Climate Change in the United States AU - Awasthi, C. AU - Archfield, S.A. AU - Kiang, J.E. AU - Ryberg, K.R. AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - The Utility of Gauge-measured Streamflow Records in Improving Month-ahead Streamflow Forecasts through Variational Data Assimilation AU - Mazrooei, A. AU - Arumugam, S. AU - Wood, A. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - CONF TI - Understanding Drivers of Subseasonal to Seasonal Streamflow Variability over Contiguous United States AU - Mukhopadhyay, S. AU - Wood, A. AU - Arumugam, S. AU - Rajagopalan, B. T2 - American Geophysical Union Fall Meeting C2 - 2019/// CY - San Francisco, CA DA - 2019/// PY - 2019/12/9/ ER - TY - SOUND TI - Challenges in Understanding Continental Scale Groundwater Variability, Change and Appropriation AU - Arumugam, S. DA - 2019/// PY - 2019/// ER - TY - JOUR TI - A practical approach to incorporate roughness-induced dynamic loads in pavement design and performance prediction AU - Goenaga, Boris AU - Fuentes, Luis AU - Mora, Otto T2 - Arabian Journal for Science and Engineering DA - 2019/// PY - 2019/// VL - 44 IS - 5 SP - 4339-4348 ER - TY - CONF TI - Meaningful learning through virtual tutors: a case study AU - Coronell, Garis AU - Calle, Maria AU - Goenaga, Boris T2 - IEEE C2 - 2019/// C3 - 2019 IEEE Global Engineering Education Conference (EDUCON) DA - 2019/// SP - 276-279 ER - TY - JOUR TI - Destination choice modeling using location-based social media data AU - Hasnat, Md Mehedi AU - Faghih-Imani, Ahmadreza AU - Eluru, Naveen AU - Hasan, Samiul AU - others T2 - J. Choice Model DA - 2019/// PY - 2019/// VL - 31 SP - 22-34 ER - TY - BOOK TI - Independent Assessment of Science and Technology for the Department of Energy's Defense Environmental Cleanup Program AB - Download a PDF of "Independent Assessment of Science and Technology for the Department of Energy's Defense Environmental Cleanup Program" by the National Academies of Sciences, Engineering, and Medicine for free. DA - 2019/// PY - 2019/// DO - 10.17226/25338 SE - 1-106 ER - TY - CONF TI - Assessment of Lateral Spreading Estimations through the Lens of Centrifuge Modeling AU - Doostmohammadibueini, M. AU - Cabas, A. AU - Montoya, B. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering C2 - 2019/// C3 - Proceedings from ASCE GeoCongress 2019 CY - Philadelphia, Pennsylvania DA - 2019/// PY - 2019/3/24/ PB - ASCE Geotechnical Special Publication ER - TY - CONF TI - Assessment of Lateral Spreading Case Histories from Recent Seismic Events: Port-Au-Prince, Haiti 2010, and Christchurch, New Zealand 2011 AU - Ingabire-Abayo, N. AU - Cabas, A. AU - Montoya, B. A2 - Ching, J. A2 - Li, D. A2 - Zhang, J. C2 - 2019/// C3 - Proceedings from the 7th International Symposium on Geotechnical Safety and Risk DA - 2019/// PY - 2019/12/11/ PB - Research Publishing ER - TY - CONF TI - Ground motion selection using the conditional spectrum: insights for different tectonic environments AU - Chowdhury, I. AU - Cabas, A. AU - Kaklamanos, J. AU - Kottke, A. AU - Greggor, N. A2 - Silvestri, F. A2 - Morcai, N. C2 - 2019/5/17/ C3 - Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions: Proceedings of the VII ICEGE Seventh International Conference on Earthquake Geotechnical Engineering DA - 2019/5/17/ SP - 1803–1811 PB - CRC Press ER - TY - RPRT TI - Geotechnical Engineering Reconnaissance of the 30 November 2018 M7.0 Anchorage, Alaska Earthquake AU - Koehler, R.D. AU - Franke, K.W. AU - Beyzaei, C.Z. AU - Cabas, A. AU - Pierce, I. AU - Stuedlein, A. AU - Yang, Z. A3 - GEER Association DA - 2019/// PY - 2019/// DO - 10.18118/G6P07F M3 - GEER report Version 2. PB - GEER Association UR - http://www.geerassociation.org/administrator/components/com_geer_reports/geerfiles/2018_Anchorage_Earthquake_Report_Version_1.pdf ER - TY - JOUR TI - Advancing the Understanding of Storm Processes and Impacts AU - Elko, N. AU - Dietrich, J.C. AU - Cialone, M. AU - Stockdon, H. AU - Bilskie, M.V. AU - Boyd, B. AU - Charbonneau, B. AU - Cox, D. AU - Dresback, K.M. AU - Elgar, S. AU - Lewis, A. AU - Limber, P. AU - Long, J. AU - Massey, T.C. AU - Mayo, T. AU - McIntosh, K. AU - Nadal, N. AU - Raubenheimer, B. AU - Tomiczek, T. AU - Wargula, A. T2 - Shore & Beach DA - 2019/// PY - 2019/// VL - 87 IS - 1 SP - 37-51 ER - TY - CONF TI - Assessing the Effectiveness of Individual Learning in a Realistic Engineering Design Class AU - Delgado, C. AU - Norville, K. AU - Han, K. AU - Lobaton, E. AU - Wu, T. C2 - 2019/3/10/ C3 - 2019 American Society for Engineering Education Southeastern Section Conference DA - 2019/3/10/ SP - 10–12, PB - American Society for Engineering Education Southeastern Section Conference UR - http://www.asee-se.org/proceedings/ASEE2019/papers2019/138.pdf ER - TY - CONF TI - Vision-Based Obstacle Removal System for Autonomous Ground Vehicles Using a Robotic Arm AB - The use of camera-equipped robotic platforms for data collection and visually monitoring applications is exponentially growing. Cluttered construction sites with many objects on the ground are challenging environments for a mobile unmanned ground vehicle (UGV) to navigate. This study presents a mobile UGV equipped with a stereo camera and a robotic arm that can remove obstacles along the UGV’s path. To achieve this, the surrounding environment is captured by the stereo camera and obstacles are detected. The obstacle’s relative location to the UGV is sent to the robotic arm module through robot operating system (ROS). Then, the robotic arm picks up and removes the obstacle. The proposed method will greatly enhance the degree of automation and frequency of data collection for construction monitoring. The results successfully demonstrate the detection and removal of obstacles, serving as one of the enabling factors for developing an autonomous UGV with various construction operating applications. C2 - 2019/6/13/ C3 - Computing in Civil Engineering 2019 DA - 2019/6/13/ DO - 10.1061/9780784482438.042 UR - http://dx.doi.org/10.1061/9780784482438.042 ER - TY - CONF TI - Virtual Manipulation in an Immersive Virtual Environment: Simulation of Virtual Assembly AB - To fill the lack of research efforts in virtual assembly of modules and training, this paper presents a virtual manipulation of building objects in an immersive virtual environment (IVE). A worker wearing a virtual reality (VR) head-mounted device (HMD) virtually perform an assembly of multiple modules while identifying any issues. Hand motions of the worker are tracked by a motion sensor mounted on the HMD. The worker can be graded based on his/her overall performance and speed during this VR simulation. The developed VR simulation can ultimately enable workers to identify unforeseen issues (e.g., not enough clearance for an object to be installed). The presented method can solve current deficiencies in discrepancy detection in 3D scanned models of elements. The developed VR platform can also be used for interactive training and simulation sessions that can potentially improve efficiency and help achieve better work performance for assemblies of complex systems. C2 - 2019/6/13/ C3 - Computing in Civil Engineering 2019 DA - 2019/6/13/ DO - 10.1061/9780784482421.013 UR - http://dx.doi.org/10.1061/9780784482421.013 ER - TY - CONF TI - Real-Time Scene Segmentation Using a Light Deep Neural Network Architecture for Autonomous Robot Navigation on Construction Sites AB - Camera-equipped unmanned vehicles (UVs) have received a lot of attention in data collection for construction monitoring applications. To develop an autonomous platform, the UV should be able to process multiple modules on an embedded platform. Pixel-wise semantic segmentation provides a UV with the ability to be contextually aware of its surrounding environment. However, in the case of mobile robotic systems with limited computing resources, the large size of the segmentation model and high memory usage requires high computing resources, which a major challenge for mobile UVs. To overcome this challenge, this paper presents a light and efficient deep neural network architecture to run on an embedded platform in real-time. The proposed model segments navigable space on an image sequence (i.e., a video stream). The results demonstrate the performance efficiency of the proposed architecture compared to the existing models and suggest possible improvements that could make the model even more efficient. C2 - 2019/6/13/ C3 - Computing in Civil Engineering 2019 DA - 2019/6/13/ DO - 10.1061/9780784482438.041 UR - http://dx.doi.org/10.1061/9780784482438.041 ER - TY - CONF TI - Real-Time Hazard Proximity Detection—Localization of Workers Using Visual Data AB - Research indicates that workers often fail to recognize a significant proportion of safety hazards. To reduce injury likelihood, efforts have traditionally focused on developing and delivering training interventions. Despite such efforts, desirable levels of hazard recognition are rarely achieved. Therefore, augmenting human abilities with a technology-driven solution to improve overall hazard recognition can yield substantial benefits. Accordingly, the objective of this study is to develop a method for localizing workers with respect to pre-identified hazards in real-time. To achieve this objective, a 3D point cloud of a construction site as a global map is created and hazard locations are marked on this map. Workers are provided with a head-mounted camera that continuously records their first-person view (FPV) videos. The image frames from these videos are localized onto the global map using bag of word (BoW) localization. Apart from estimating the proximity to safety hazards, the system can also capture large-scale data that captures unsafe behaviors (e.g., entry to restricted areas) and near-miss incidents for training purposes. C2 - 2019/6/13/ C3 - Computing in Civil Engineering 2019 DA - 2019/6/13/ DO - 10.1061/9780784482438.036 UR - http://dx.doi.org/10.1061/9780784482438.036 ER - TY - JOUR TI - Does Granular Activated Carbon with Chlorination Produce Safer Drinking Water? From Disinfection Byproducts and Total Organic Halogen to Calculated Toxicity AU - Cuthbertson, Amy A. AU - Kimura, Susana Y. AU - Liberatore, Hannah K. AU - Summers, R. Scott AU - Knappe, Detlef R. U. AU - Stanford, Benjamin D. AU - Maness, J. Clark AU - Mulhern, Riley E. AU - Selbes, Meric AU - Richardson, Susan D. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Granular activated carbon (GAC) adsorption is well-established for controlling regulated disinfection byproducts (DBPs), but its effectiveness for unregulated DBPs and DBP-associated toxicity is unclear. In this study, GAC treatment was evaluated at three full-scale chlorination drinking water treatment plants over different GAC service lives for controlling 61 unregulated DBPs, 9 regulated DBPs, and speciated total organic halogen (total organic chlorine, bromine, and iodine). The plants represented a range of impacts, including algal, agricultural, and industrial wastewater. This study represents the most extensive full-scale study of its kind and seeks to address the question of whether GAC can make drinking water safer from a DBP perspective. Overall, GAC was effective for removing DBP precursors and reducing DBP formation and total organic halogen, even after >22 000 bed volumes of treated water. GAC also effectively removed preformed DBPs at plants using prechlorination, including highly toxic iodoacetic acids and haloacetonitriles. However, 7 DBPs (mostly brominated and nitrogenous) increased in formation after GAC treatment. In one plant, an increase in tribromonitromethane had significant impacts on calculated cytotoxicity, which only had 7-17% reduction following GAC. While these DBPs are highly toxic, the total calculated cytotoxicity and genotoxicity for the GAC treated waters for the other two plants was reduced 32-83% (across young-middle-old GAC). Overall, calculated toxicity was reduced post-GAC, with preoxidation allowing further reductions. DA - 2019/5/21/ PY - 2019/5/21/ DO - 10.1021/acs.est.9b00023 VL - 53 IS - 10 SP - 5987-5999 SN - 1520-5851 ER - TY - JOUR TI - Damage assessment of asphalt concrete with composite additives at the FAM–coarse aggregate interfacial zone AU - Niu, Dongyu AU - Chen, Huaxin AU - Richard Kim, Y. AU - Sheng, Yanping AU - Geng, Jiuguang AU - Guan, Bowen AU - Xiong, Rui AU - Yang, Zhengxian T2 - Construction and Building Materials AB - Asphalt concrete (AC) is of a three-phase system comprising of coarse aggregate, FAM (fine aggregate matrix) and interfacial zones (ITZ). The interfacial zone between FAM and coarse aggregate plays a critical role which determines the mechanical performance. This paper presents a numerical simulation of the mechanical behavior of ITZ, to quantitatively analyze damage of AC with or without composite additives. The results indicated that damage at the ITZ was initiated from the top area followed by a downward propagation. Both cohesive and adhesive damage of AC with composite additives were less serious than that without composite additives, and the damage severity was greatly affected by the thickness of FAM layer. The most serious damage was observed for the thick FAM layer under a rectangular loading pattern. As such, the adhesive damage area and cohesive damage area of AC with composite additives were found to be 1.7% and 33.8% respectively, less than that without composite additives. DA - 2019/2// PY - 2019/2// DO - 10.1016/J.CONBUILDMAT.2018.11.272 VL - 198 SP - 587-596 J2 - Construction and Building Materials LA - en OP - SN - 0950-0618 UR - http://dx.doi.org/10.1016/J.CONBUILDMAT.2018.11.272 DB - Crossref KW - Damage KW - Asphalt concrete KW - Fine aggregate matrix KW - Interfacial zones KW - Cohesive zone modeling ER - TY - JOUR TI - Probabilistic Characterization of an Allowable Design Moment in a Piping Elbow AU - Ryu, Yonghee AU - Gupta, Abhinav AU - Ju, Bu Seog T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - The design of a nuclear power plant piping requires consideration of the effects of pressure and moment loads according to the appropriate design equation, which is Piping design equation (9) in NC/ND-3600, Section III of the ASME Boiler and Pressure Vessel Code. The design moment is influenced significantly by the definition of the B2 stress index in piping elbows. This paper presents a study on reliability-based design for piping elbows on the level D service limit in the design code. Probability density functions (PDFs) of the design moment were calculated using the ASME equation and modified B2 equations. The PDFs of the design moment were evaluated by the collapse moment using the closed-form equations. The probability distribution of the design moment using the modified B2 equation was closer to the distributions of the collapse moment than its design moment using the ASME B2 equation. Probabilistic analyses were conducted to evaluate reliability levels in straight pipe as well as piping elbows using the ASME and modified B2 equations. It was observed that the minimum reliability level (MRL) of the design equation for the straight pipe was slightly higher than the MRL of the elbow. The MRLs of the design equation using the ASME and modified B2 equations were similar for the same values of bend parameter h, and the MRL of the design equation did not show influence of changes in bend parameter, piping type, and B2 stress index. DA - 2019/6// PY - 2019/6// DO - 10.1115/1.4042907 VL - 141 IS - 3 SP - SN - 1528-8978 KW - LRFD design for piping elbow KW - piping elbow reliability KW - reliability-based code calibration KW - performance-based design of piping elbow ER - TY - JOUR TI - Development of scanning electron microscope-compatible multiaxial miniature testing system AU - Rahman, Farhan AU - Ngaile, Gracious AU - Hassan, Tasnim T2 - MEASUREMENT SCIENCE AND TECHNOLOGY AB - Knowledge of deformation and failure mechanisms at micro- to nano-length scales is important for the prediction of material behavior as well as the development of new materials with desired properties. In situ multiaxial testing with scanning electron microscopes (SEM) can reveal physical deformation mechanisms under realistic multiaxial loading conditions. Although in situ SEM testing has gained traction in recent years, there is currently no multiaxial in situ SEM testing stage available with axial-torsional loading capabilities which can generally be used in any SEM. In this study, we report the development of a multiaxial miniature testing system (MMTS) with a unique capability for performing axial-torsional testing of a tubular specimen with a 1–2 mm outer diameter, inside most SEMs. The different challenges of developing a multiaxial in situ SEM testing stage, such as small load frame size, appropriate specimen position, high vacuum compatibility of MMTS load frame components, as well as the development of installation accessories, were addressed. A custom SEM stage door was developed for the MMTS load frame. Verification tests have confirmed the successful development of the MMTS for in situ SEM testing. In addition, digital image correlation was used with recorded SEM images during the test to determine the surface strain. DA - 2019/10// PY - 2019/10// DO - 10.1088/1361-6501/ab1ca6 VL - 30 IS - 10 SP - SN - 1361-6501 KW - miniature test KW - multiaxial test KW - in situ testing KW - scanning electron microscope KW - digital image correlation ER - TY - CONF TI - Bounded Verification of Sparse Matrix Computations AU - Dyer, Tristan AU - Altuntas, Alper AU - Baugh, John AB - We show how to model and reason about the structure and behavior of sparse matrices, which are central to many applications in scientific computation. Our approach is state-based, relying on a formalism called Alloy to show that one model is a refinement of another. We present examples of sparse matrix-vector multiplication, transpose, and translation between formats using ELLPACK and compressed sparse row formats to demonstrate the approach. To model matrix computations in a declarative language like Alloy, a new idiom is presented for bounded iteration with incremental updates. Mechanical verification is performed using SAT solvers built into the tool. C2 - 2019/11// C3 - 2019 IEEE/ACM 3rd International Workshop on Software Correctness for HPC Applications (Correctness) DA - 2019/11// DO - 10.1109/correctness49594.2019.00010 SP - 36-43 PB - IEEE/ACM UR - http://dx.doi.org/10.1109/correctness49594.2019.00010 KW - sparse matrix formats KW - state-based formal methods KW - mechanical verification ER - TY - JOUR TI - The effect of laboratory compaction method on the resilient behaviour and fabric of aggregate base course materials AU - Bozorgi, Arash AU - Fried, Andrew AU - Montoya, Brina M. AU - Castorena, Cassie T2 - Road Materials and Pavement Design AB - Aggregate base course (ABC) layer is a key structural component of most pavements. The compaction of ABC is a crucial procedure affecting its mechanical performance. There are two different methods commonly used in the lab to compact ABC specimens: impact and vibratory. Past studies have demonstrated that the compaction method can affect the resilient deformation behaviour of ABC. However, the reasons for these differences in terms of the constituent ABC particle properties and the resultant compacted aggregate fabric remains unclear. This study evaluates the influence of the laboratory compaction method on the resilient behaviour and fabric of two ABC materials with differing mineralogies. Resilient modulus tests performed on the specimens compacted with the two methods result in different behaviours. A series of subsequent laboratory tests were performed to explain the observed resilient behaviour by assessing changes in aggregate morphology and fabric. The study presented herein incorporates digital imaging analyses using a novel specimen preparation technique. The results demonstrate that impact compaction can degrade ABC materials that are susceptible to crushing. This, in turn, increases the resilient modulus of the ABC by increasing the number of contact points between particles. It is recommended that the compaction method used in the laboratory match the compaction processes in the field as best as possible to obtain the most representative resilient modulus test results. DA - 2019/2/19/ PY - 2019/2/19/ DO - 10.1080/14680629.2019.1580606 VL - 2 SP - 1-13 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2019.1580606 DB - Crossref KW - aggregate base course KW - resilient modulus KW - compaction KW - fabric KW - digital image analysis KW - particle contacts ER - TY - CONF TI - MICP AU - Do, Jinung AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering AB - In this study, injection configuration system to stabilize soil mass around a pile foundation with the microbially induced carbonate precipitation was developed and a simplified scheme for field implementation was proposed using seepage and chemical transport analysis. Experimental testing included a tracer experiment in a large-scale soil box with the results used to calibrate transport parameters for the numerical model. Results indicated that the use of a central injection through the pile lead to effective distribution of the tracer within the flow domain. The radius of the zone of influence was estimated as 8.5D based on the induced flow hydraulic gradient of 0.7. Target concentration was used as a design criterion to determine the injection duration. Analyses indicated 7.5 days of injection duration was needed to affect a zone having 4D extent with a tracer concentration of 100%. Recommendations are presented regarding volume treatment scenarios with the use of single point injections. C2 - 2019/3/21/ C3 - Geo-Congress 2019 DA - 2019/3/21/ DO - 10.1061/9780784482117.028 PB - American Society of Civil Engineers SN - 9780784482117 UR - http://dx.doi.org/10.1061/9780784482117.028 DB - Crossref ER - TY - CONF TI - MICP AU - Ghasemi, Pegah AU - Zamani, Atefeh AU - Montoya, Brina T2 - Eighth International Conference on Case Histories in Geotechnical Engineering AB - Sandy slopes supporting coastal roadways are susceptible to failure during large storm events due to erosion and slope stability. Investigating the application of a natural and sustainable soil improvement method is required to increase the shear strength and erosion resistance of sands while having less impact on the coastal ecology. Microbial induced calcium carbonate precipitation (MICP) is a novel and promising soil improvement technique that utilizes indigenous soil bacteria to hydrolyze urea and induce calcium carbonate precipitation, which improves the mechanical properties of the soil. The chemical concentrations and recipe ratios used for this process can affect the level of improvement. This study aims to draw a relationship between the chemical ratios, shear strength, and erodibility resistance of MICP treated sands. In an attempt to tailor the laboratory experiments closer to field requirements, industrial grade chemicals were used to treat the soil specimens. A submerged impinging jet system was used to evaluate the erodibility parameters of soil specimens treated with different ratios of urea to calcium chloride. Unconfined compression strength tests (UCS), an indication of shear strength, were performed on specimens with similar properties treated with different ratios of urea to calcium chloride. Shear wave velocity measurements were used to detect the level of improvement in all soil specimens during the treatment. The results indicate that the ratio of urea to calcium chloride can affect the number of treatments required to reach a target level of improvement. In addition, the ratio of chemical concentrations can change the erosion strength differently compared to the UCS. These results can also provide a basis for choosing an optimum treatment recipe for field application, by keeping a balance between the mechanical properties of MICP treated soils, mass of calcium carbonate, and cost of chemicals used for treatment. C2 - 2019/3/21/ C3 - Geo-Congress 2019 DA - 2019/3/21/ DO - 10.1061/9780784482117.024 PB - American Society of Civil Engineers SN - 9780784482117 UR - http://dx.doi.org/10.1061/9780784482117.024 DB - Crossref ER - TY - CONF TI - MICP AU - Nafisi, Ashkan AU - Montoya, Brina M. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering C2 - 2019/3/21/ C3 - Geo-Congress 2019 DA - 2019/3/21/ DO - 10.1061/9780784482117.020 PB - American Society of Civil Engineers SN - 9780784482117 UR - http://dx.doi.org/10.1061/9780784482117.020 DB - Crossref ER - TY - CONF TI - Computational Geotechnics AU - Rafiei, Amin AU - Rahman, M. S. AU - Gabr, M. A. T2 - Eighth International Conference on Case Histories in Geotechnical Engineering AB - Instability of seabed due to wave action may cause serious damages to coastal infrastructure. The wave-induced instantaneous liquefaction near and around a structure, may impact the stability and capacity of foundation elements. The wave-seabed interaction has been mostly studied based on decoupled analysis for the flat or slightly sloping seabed (slope less than five degrees). However, some of marine structures, near shore may be built on (or anchored to) seabed with considerable slopes. In this paper, the response and instability of the sloping seabed supporting a marine structure and subjected to surface waves is evaluated. The scope included developing a numerical model using a fully coupled approach. Biot’s equations of the seabed in conjunction with governing equations for other domains (structure and fluid regions) are solved simultaneously using finite element method. The instability of seabed due to wave-induced instantaneous liquefaction around the marine structure is evaluated and the effect of slope on the extent of liquefied zone is examined. The results indicated that seabed response and the extent of liquefied zone near the structure are reduced with increasing steepness of seabed. The effect of various slope steepness and soil parameters on the extent of the liquefied zone is characterized and discussed. C2 - 2019/3/21/ C3 - Geo-Congress 2019 DA - 2019/3/21/ DO - 10.1061/9780784482124.019 PB - American Society of Civil Engineers SN - 9780784482124 UR - http://dx.doi.org/10.1061/9780784482124.019 DB - Crossref ER - TY - JOUR TI - Development of a novel constitutive model for improved structural integrity analysis of piping components AU - Islam, Nazrul AU - Hassan, Tasnim T2 - INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING AB - Elbows are critical components of piping systems in the nuclear power industry, however, existing constitutive models are unable to simulate the low-cycle fatigue and ratcheting responses of this component. This study developed a constitutive model, incorporating a novel and various advanced uniaxial and multiaxial modeling features for successful response simulations of stainless steel (SS) 304 short and long radius elbows subjected to internal pressure and opening-closing displacement-controlled cycles. Simulated results demonstrate that if an existing advanced constitutive model is calibrated solely based on the material level responses, it is not able to simulate the elbow responses with acceptable accuracy. This drawback is primarily attributed to the fact that the prior loading and loading histories at different locations in an elbow are different and not represented by the loading histories of the material experiments performed for model parameter determination. Hence, model development and simultaneous experimental verification at the material and component levels trace the drawbacks of the constitutive modeling features effectively. Such evaluation of the simulated responses at two levels provided a novel modeling concept in improving the elbow response simulations quite satisfactorily. The implemented modeling features and response simulations at both levels are presented and critically analyzed for providing insights in developing robust constitutive models for structural integrity analysis. DA - 2019/11// PY - 2019/11// DO - 10.1016/j.ijpvp.2019.103989 VL - 177 SP - SN - 1879-3541 KW - Elbow low-cycle-fatigue KW - Uniaxial ratcheting KW - Multiaxial ratcheting KW - Strain-range dependence KW - Nonproportional hardening KW - Chaboche model ER - TY - JOUR TI - Do commercial buildings become less efficient when they provide grid ancillary services? AU - Keskar, Aditya AU - Anderson, David AU - Johnson, Jeremiah X. AU - Hiskens, Ian A. AU - Mathieu, Johanna L. T2 - Energy Efficiency DA - 2019/4/2/ PY - 2019/4/2/ DO - 10.1007/S12053-019-09787-X J2 - Energy Efficiency LA - en OP - SN - 1570-646X 1570-6478 UR - http://dx.doi.org/10.1007/S12053-019-09787-X DB - Crossref KW - Ancillary services KW - Energy efficiency KW - Commercial buildings KW - HVAC KW - Building controls KW - Demand response ER - TY - JOUR TI - Bayesian mechanistic modeling characterizes Gulf of Mexico hypoxia: 1968-2016 and future scenarios AU - Giudice, Dario Del AU - Matli, V. R. R. AU - Obenour, Daniel T2 - ECOLOGICAL APPLICATIONS AB - Abstract The hypoxic zone in the northern Gulf of Mexico is among the most dramatic examples of impairments to aquatic ecosystems. Despite having attracted substantial attention, management of this environmental crisis remains challenging, partially due to limited monitoring to support model development and long‐term assessments. Here, we leverage new geostatistical estimates of hypoxia derived from nearly 150 monitoring cruises and a process‐based model to improve characterization of controlling mechanisms, historic trends, and future responses of hypoxia while rigorously quantifying uncertainty in a Bayesian framework. We find that November–March nitrogen loads are important controls of sediment oxygen demand, which appears to be the major oxygen sink. In comparison, only ~23% of oxygen in the near‐bottom region appears to be consumed by net water column respiration, which is driven by spring and summer loads. Hypoxia typically exceeds 15,600 km 2 in June, peaks in July, and declines below 10,000 km 2 in September. In contrast to some previous Gulf hindcasting studies, our simulations demonstrate that hypoxia was both severe and worsening prior to 1985, and has remained relatively stable since that time. Scenario analysis shows that halving nutrient loadings will reduce hypoxia by 37% with respect to 13,900 km 2 (1985–2016 median), while a +2°C change in water temperature will cause a 26% hypoxic area increase due to enhanced sediment respiration and reduced oxygen solubility. These new results highlight the challenges of achieving hypoxia reduction targets, particularly under warming conditions, and should be considered in ecosystem management. DA - 2019/// PY - 2019/// DO - 10.1002/eap.2032 KW - Bayesian inference KW - climate change KW - dead hypoxic zones KW - eutrophication KW - Gulf of Mexico KW - hindcasts and projections KW - process-based modeling KW - riverine nitrogen KW - uncertainty quantification ER - TY - JOUR TI - Aligning evidence generation and use across health, development, and environment AU - Tallis, Heather AU - Kreis, Katharine AU - Olander, Lydia AU - Ringler, Claudia AU - Ameyaw, David AU - Borsuk, Mark E. AU - Fletschner, Diana AU - Game, Edward AU - Gilligan, Daniel O. AU - Jeuland, Marc AU - Kennedy, Gina AU - Masuda, Yuta J. AU - Mehta, Sumi AU - Miller, Nicholas AU - Parker, Megan AU - Pollino, Carmel AU - Rajaratnam, Julie AU - Wilkie, David AU - Zhang, Wei AU - Ahmed, Selena AU - Ajayi, Oluyede C. AU - Alderman, Harold AU - Arhonditsis, George AU - Azevedo, Ines AU - Badola, Ruchi AU - Bailis, Rob AU - Balvanera, Patricia AU - Barbour, Emily AU - Bardini, Mark AU - Barton, David N. AU - Baumgartner, Jill AU - Benton, Tim G. AU - Bobrow, Emily AU - Bossio, Deborah AU - Bostrom, Ann AU - Braimoh, Ademola AU - Brondizio, Eduardo AU - Brown, Joe AU - Bryant, Benjamin P. AU - Calder, Ryan Sd AU - Chaplin-Kramer, Becky AU - Cullen, Alison AU - DeMello, Nicole AU - Dickinson, Katherine L. AU - Ebi, Kristie L. AU - Eves, Heather E. AU - Fanzo, Jessica AU - Ferraro, Paul J. AU - Fisher, Brendan AU - Frongillo, Edward A. AU - Galford, Gillian AU - Garrity, Dennis AU - Gatere, Lydiah AU - Grieshop, Andrew P. AU - Grigg, Nicola J. AU - Groves, Craig AU - Gugerty, Mary Kay AU - Hamm, Michael AU - Hou, Xiaoyue AU - Huang, Cindy AU - Imhoff, Marc AU - Jack, Darby AU - Jones, Andrew D. AU - Kelsey, Rodd AU - Kothari, Monica AU - Kumar, Ritesh AU - Lachat, Carl AU - Larsen, Ashley AU - Lawrence, Mark AU - DeClerck, Fabrice AU - Levin, Phillip S. AU - Mabaya, Edward AU - Gibson, Jacqueline MacDonald AU - McDonald, Robert I AU - Mace, Georgina AU - Maertens, Ricardo AU - Mangale, Dorothy I AU - Martino, Robin AU - Mason, Sara AU - Mehta, Lyla AU - Meinzen-Dick, Ruth AU - Merz, Barbara AU - Msangi, Siwa AU - Murray, Grant AU - Murray, Kris A. AU - Naude, Celeste E. AU - Newlands, Nathaniel K. AU - Nkonya, Ephraim AU - Peterman, Amber AU - Petruney, Tricia AU - Possingham, Hugh AU - Puri, Jyotsna AU - Remans, Roseline AU - Remlinger, Lisa AU - Ricketts, Taylor H. AU - Reta, Bedilu AU - Robinson, Brian E. AU - Roe, Dilys AU - Rosenthal, Joshua AU - Shen, Guofeng AU - Shindell, Drew AU - Stewart-Koster, Ben AU - Sunderland, Terry AU - Sutherland, William J. AU - Tewksbury, Josh AU - Wasser, Heather AU - Wear, Stephanie AU - Webb, Chris AU - Whittington, Dale AU - Wilkerson, Marit AU - Wittmer, Heidi AU - Wood, Benjamin D. K. AU - Wood, Stephen AU - Wu, Joyce AU - Yadama, Gautam AU - Zobrist, Stephanie T2 - CURRENT OPINION IN ENVIRONMENTAL SUSTAINABILITY AB - Although health, development, and environment challenges are interconnected, evidence remains fractured across sectors due to methodological and conceptual differences in research and practice. Aligned methods are needed to support Sustainable Development Goal advances and similar agendas. The Bridge Collaborative, an emergent research-practice collaboration, presents principles and recommendations that help harmonize methods for evidence generation and use. Recommendations were generated in the context of designing and evaluating evidence of impact for interventions related to five global challenges (stabilizing the global climate, making food production sustainable, decreasing air pollution and respiratory disease, improving sanitation and water security, and solving hunger and malnutrition) and serve as a starting point for further iteration and testing in a broader set of contexts and disciplines. We adopted six principles and emphasize three methodological recommendations: (1) creation of compatible results chains, (2) consideration of all relevant types of evidence, and (3) evaluation of strength of evidence using a unified rubric. We provide detailed suggestions for how these recommendations can be applied in practice, streamlining efforts to apply multi-objective approaches and/or synthesize evidence in multidisciplinary or transdisciplinary teams. These recommendations advance the necessary process of reconciling existing evidence standards in health, development, and environment, and initiate a common basis for integrated evidence generation and use in research, practice, and policy design. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.cosust.2019.09.004 VL - 39 SP - 81-93 SN - 1877-3443 ER - TY - JOUR TI - Micropillar compression investigation of size effect on microscale strength and failure mechanism of Calcium-Silicate-Hydrates (C-S-H) in cement paste AU - Shahrin, Rahnuma AU - Bobko, Christopher P. T2 - CEMENT AND CONCRETE RESEARCH AB - The compressive strength and failure of concrete and cement exhibit strong size effect over various length scales. To investigate possible size effect on compressive strength and failure mechanism of Calcium-Silicate-Hydrates (C-S-H) in cement paste, micropillar compression experiments were performed on micropillar geometries fabricated by focused ion beam milling on potential C-S-H locations identified through coupled backscatter electron imaging (BSE) and energy dispersive spectroscopy (EDS) analysis. The compressive strength of C-S-H (181–1145 MPa) measured from C-S-H micropillars of varying diameters indicated presence of a size effect with strong increase in strength with decreasing diameter. The deformation mode at failure also exhibited size effect: the dominant failure mode changed from axial splitting to plastic crushing as the pillar diameter was decreased. The observed relationship between strength and pillar diameter can be modeled by an inverse square root dependency which closely corresponds to Bazant's scaling law of quasi-brittle failure. DA - 2019/11// PY - 2019/11// DO - 10.1016/j.cemconres.2019.105863 VL - 125 SP - SN - 1873-3948 KW - SEM KW - Calcium-Silicate-Hydrate (C-S-H) KW - Cement paste KW - Compressive strength KW - Size effect ER - TY - JOUR TI - Queue-Based Guidance for Signalization Consideration at Two and Three-Legged Intersections AU - Warchol, Shannon AU - Rouphail, Nagui M. AU - Vaughan, Chris AU - Kearns, Brendan T2 - TRANSPORTATION RESEARCH RECORD AB - This research collected and analyzed gap acceptance in North Carolina to develop a data-driven method for determining the need for considering additional signalization analysis at intersections with fewer than four legs. This method can be used for movements that merge with or cross two lanes of oncoming traffic. It is intended to provide guidance and support to traffic engineers in their decision-making process. Charts are provided to determine the expected 95th percentile queue lengths for left-turn, right-turn, and U-turn movements crossing or merging with two lanes of conflicting traffic. This situation is typically present along four-lane roadways where a one-way primary movement opposes either a minor road right-turn movement or a left-turn movement, or in the case of a median U-turn opening. Adjustment factors to the conflicting flowrate were developed to account for the presence of upstream signalized intersections. This method less frequently recommends further signal consideration when compared with the Manual on Uniform Traffic Control Devices peak hour warrant, but is similar to the delay-based level of service D/E threshold for two-way stop-controlled intersections in HCM6 Chapter 19. DA - 2019/10// PY - 2019/10// DO - 10.1177/0361198119847468 VL - 2673 IS - 10 SP - 416-426 SN - 2169-4052 ER - TY - JOUR TI - Investigations on fracture characteristics of geosynthetic reinforced asphalt concrete beams using single edge notch beam tests AU - Sudarsanan, Nithin AU - Karpurapu, Rajagopal AU - Amirthalingam, Veeraragavan T2 - GEOTEXTILES AND GEOMEMBRANES AB - Reflective cracking is a major cause for premature deterioration of asphalt pavements. Different varieties of geosynthetics are used at the interfaces of surface layers to control the reflective cracks. The significant factors influencing their efficiency are the flexural strength and interfacial bonding. Fracture energy that leads to development of cracks and their propagation can be investigated by single-edge notched beam (SENB) tests with sufficient accuracy. Double layered asphalt samples were extracted from pavement sections purposely built as part of this investigation for conducting quasi-static SENB tests. The goal of this paper is two-fold (a) to present a methodology for conducting SENB tests to measure the fracture properties of geosynthetic reinforced samples at temperatures of 10 °C, 20 °C and 30 °C and (b) evaluation of the flexural and the fracture characteristics of unreinforced and geosynthetic reinforced samples. The geosynthetic reinforcement did not show much improvement of the Asphalt Concrete (AC) in the pre-cracking phase but slowed down the crack propagation. The failure pattern of reinforced specimens has changed from quasi-brittle to ductile. An equation is proposed to predict the crack initiation force of SENB sample knowing the bond strength of the corresponding reinforced AC layers at their respective temperature. DA - 2019/10// PY - 2019/10// DO - 10.1016/j.geotexmem.2019.103461 VL - 47 IS - 5 SP - 642-652 SN - 1879-3584 KW - Geosynthetics KW - Natural geotextiles KW - Single edge notched beam test KW - Fracture energy KW - Reflective cracking ER - TY - JOUR TI - Trend Analysis on Adoption of Virtual and Augmented Reality in the Architecture, Engineering, and Construction Industry AU - Noghabaei, Mojtaba AU - Heydarian, Arsalan AU - Balali, Vahid AU - Han, Kevin AB - With advances in Building Information Modeling (BIM), Virtual Reality (VR) and Augmented Reality (AR) technologies have many potential applications in the Architecture, Engineering, and Construction (AEC) industry. However, the AEC industry, relative to other industries, has been slow in adopting AR/VR technologies, partly due to lack of feasibility studies examining the actual cost of implementation versus an increase in profit. The main objectives of this paper are to understand the industry trends in adopting AR/VR technologies and identifying gaps within the industry. The identified gaps can lead to opportunities for developing new tools and finding new use cases. To achieve these goals, two rounds of a survey at two different time periods (a year apart) were conducted. Responses from 158 industry experts and researchers were analyzed to assess the current state, growth, and saving opportunities for AR/VR technologies for the AEC industry. The findings demonstrate that older generations are significantly more confident about the future of AR/VR technologies and they see more benefits in AR/VR utilization. Furthermore, the research results indicate that Residential and commercial sectors have adopted these tools the most, compared to other sectors and institutional and transportation sectors had the highest growth from 2017 to 2018. Industry experts anticipated a solid growth in the use of AR/VR technologies in 5 to 10 years, with the highest expectations towards healthcare. Ultimately, the findings show a significant increase in AR/VR utilization in the AEC industry from 2017 to 2018. DA - 2019/12/29/ PY - 2019/12/29/ DO - 10.20944/preprints201912.0369.v1 VL - 12 UR - https://doi.org/10.20944/preprints201912.0369.v1 ER - TY - JOUR TI - Internships and engineering: beliefs and behaviors of academics AU - Matusovich, Holly AU - Carrico, Cheryl AU - Harris, Angela AU - Sheppard, Sheri AU - Brunhaver, Samantha AU - Streveler, Ruth AU - McGlothlin Lester, Marlena B T2 - Education+ Training DA - 2019/// PY - 2019/// ER - TY - JOUR TI - Evaluation of arsenic field test kits as a learning exercise for engineering students in global water and sanitation class AU - Kearns, J.P. AU - Krupp, A.S. AU - Hartman, S. AU - Szogas, K. AU - Boskey, M. AU - Harrington, J.M. T2 - International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship AB - Around 150 million people in more than 70 countries around the world are exposed to elevated levels of naturally occurring arsenic in groundwater used for drinking and cooking. Inexpensive arsenic field test kits are readily commercially available and have been promoted for classifying the safety of water sources. However, the accuracy and reliability of test kits has been called into question by some researchers. The purpose of this project was to provide decision support to a small nonprofit community development organization in central Mexico regarding the applicability of field test kits for assessing the safety of rural groundwater supplies. Test kit evaluation was conducted as an experiential learning exercise for undergraduate and graduate students in a University engineering course on Global Water and Sanitation. Recounting the scale and scope of the ongoing arsenic crisis in Bangladesh, as well as the sensational epidemic of “arsenical beer” in Manchester, England in 1900 that popularized the Gutzeit chemistry upon which test kits are based, spurred student interest and enthusiasm for the learning activities. Reviewing the contradictory and inconclusive literature from the recent two decades on the use of test kits provided a sobering case study for students to grapple with the difficulties and uncertainties inherent in conducting humanitarian science and engineering in the developing world. This study found generally poor performance of test kits, in particular for waters containing As in excess of 95 mg/L.The field kits tested could not be used to classify waters as “safe,” i.e., below the WHO Guideline Value of 10 mg/L to 95% level of confidence. This study lends further caution to the use of test kits for identification of safe water sources. DA - 2019/5/14/ PY - 2019/5/14/ DO - 10.24908/ijsle.v14i1.12528 VL - 14 IS - 1 SP - 32–46, UR - http://dx.doi.org/10.24908/ijsle.v14i1.12528 ER - TY - JOUR TI - Underrepresented groups in WaSH – the overlooked role of chemical toxicants in water and health AU - Kearns, J.P. AU - Bentley, M.J. AU - Mokashi, P. AU - Redmon, J.H. AU - Levine, K. T2 - Journal of Water, Sanitation and Hygiene for Development AB - Abstract The anthropogenic release of chemicals from industry, agriculture and the breakdown of consumer wastes constitute a major threat to water resources and public health. Pollution is severe and increasing in the developing world where chemical substances are produced, used, and disposed of in an unregulated manner. The global public health consequences of chemical pollution are comparable to or greater than those of widespread infectious diseases such as HIV/AIDS, tuberculosis, and malaria. However, chemicals have so far been neglected by the WaSH sector. Here, we report the results of a systematic review of the Journal of Water, Sanitation, and Hygiene for Development (2011–2018) and oral/poster presentations given at the UNC Water & Health Conference (2010–2018). The review enumerated studies that focused on water quality and treatment from a chemical perspective, highlighting in particular organic contaminants of emerging concern. Organic chemicals were addressed in only 2% of journal articles and fewer than 0.7% of conference presentations. Geogenic contaminants arsenic and fluoride were only addressed in 2–3% of articles and presentations. The review concludes that a rapid, major effort to address toxic chemicals in WaSH is necessary to meet UN Sustainable Development Goals for universal access to safe and affordable drinking water by 2030. DA - 2019/12/1/ PY - 2019/12/1/ DO - 10.2166/washdev.2019.059 VL - 9 SP - 4 UR - http://dx.doi.org/10.2166/washdev.2019.059 KW - chemicals KW - drinking water KW - health KW - inorganic KW - organic KW - toxicants ER - TY - JOUR TI - Durability of CFRP strands used for prestressing of concrete structural members AU - Khalafalla, Omar AU - Pour-Ghaz, Mohammad AU - ElSafty, Adel AU - Rizkalla, Sami T2 - CONSTRUCTION AND BUILDING MATERIALS AB - This paper presents a comprehensive research conducted to study the synergistic effect of environmental conditions and sustained loading on the mechanical properties of Carbon Fiber Reinforced Polymer (CFRP) prestressing strands. The environmental conditions included exposure of CFRP strands to alkaline solution and sustained loading at an elevated temperature of 55 °C for 3000 and 7000 h. The sustained loading was equivalent to 65 percent of the guaranteed tensile strength of the strands. Mechanical testing performed on the strands included tensile, shear and bond strength as well as evaluation of the elastic modulus of the CFRP strands as affected by the environmental conditions and sustained loading. Durability of the constituent materials of the CFRP strands was also studied. DA - 2019/12/20/ PY - 2019/12/20/ DO - 10.1016/j.conbuildmat.2019.116756 VL - 228 SP - SN - 1879-0526 KW - Durability KW - CFRP strands KW - Sustained load KW - Environmental conditions ER - TY - JOUR TI - Enhancement of Coal Ash Compressibility Parameters Using Microbial-Induced Carbonate Precipitation AU - Montoya, Brina M. AU - Safavizadeh, Shahin AU - Gabr, Mohammed A. T2 - Journal of Geotechnical and Geoenvironmental Engineering AB - Microbial-induced calcium carbonate precipitation (MICP) was experimentally implemented on two coal ash materials (i.e., CA1 and CA3) to investigate the efficacy of the treatment on the hydraulic and compressibility properties of the material. Oedometers used in testing were modified to enable the injection of treatment solutions and to provide the ability to monitor shear wave velocity. The coal ash specimens were treated to reach different levels of shear wave velocity, which corresponded to varying amounts of CaCO3 content. The hydraulic conductivity and shear wave velocity values were assessed throughout the loading process. Results indicate that the MICP treatment decreased the compressibility (compression index decreased by a factor as high as 2), and the hydraulic conductivity (decreased by a factor as much as 0.05). The slope of log(σV′)-VS relationship (β′) decreased from 0.31 for the untreated material to 0.01 with treatment. In parallel, the increase in the shear wave velocity after treatment increased the intercept of the relationship between log(σV′)-VS (i.e., α′) from 38 to 383 m/s. The correlation between small-strain and large-strain parameters are explored and discussed. DA - 2019/5// PY - 2019/5// DO - 10.1061/(ASCE)GT.1943-5606.0002036 VL - 145 IS - 5 SP - 04019018 J2 - J. Geotech. Geoenviron. Eng. LA - en OP - SN - 1090-0241 1943-5606 UR - http://dx.doi.org/10.1061/(ASCE)GT.1943-5606.0002036 DB - Crossref ER - TY - JOUR TI - Complete spatial model calibration AU - Huang, Yen-Ning AU - Reich, Brian J. AU - Fuentes, Montserrat AU - Sankarasubramanian, A. T2 - The Annals of Applied Statistics AB - Computer simulation models are central to environmental science. These mathematical models are used to understand complex weather and climate patterns and to predict the climate’s response to different forcings. Climate models are of course not perfect reflections of reality, and so comparison with observed data is needed to quantify and to correct for biases and other deficiencies. We propose a new method to calibrate model output using observed data. Our approach not only matches the marginal distributions of the model output and gridded observed data, but it simultaneously postprocesses the model output to have the same spatial correlation as the observed data. This comprehensive calibration method permits realistic spatial simulations for regional impact studies. We apply the proposed method to global climate model output in North America and show that it successfully calibrates the model output for temperature and precipitation. DA - 2019/6// PY - 2019/6// DO - 10.1214/18-aoas1219 VL - 13 IS - 2 SP - 746-766 J2 - Ann. Appl. Stat. LA - en OP - SN - 1932-6157 UR - http://dx.doi.org/10.1214/18-aoas1219 DB - Crossref KW - Bayesian methods KW - calibration KW - spatial statistics ER - TY - JOUR TI - Limitations of univariate linear bias correction in yielding cross‐correlation between monthly precipitation and temperature AU - Bhowmik, R. Das AU - Sankarasubramanian, A. T2 - International Journal of Climatology AB - Abstract Statistical bias correction techniques are commonly used in climate model projections to reduce systematic biases. Among the several bias correction techniques, univariate linear bias correction (e.g., quantile mapping) is the most popular, given its simplicity. Univariate linear bias correction can accurately reproduce the observed mean of a given climate variable. However, when performed separately on multiple variables, it does not yield the observed multivariate cross‐correlation structure. In the current study, we consider the intrinsic properties of two candidate univariate linear bias‐correction approaches (simple linear regression and asynchronous regression) in estimating the observed cross‐correlation between precipitation and temperature. Two linear regression models are applied separately on both the observed and the projected variables. The analytical solution suggests that two candidate approaches simply reproduce the cross‐correlation from the general circulation models (GCMs) in the bias‐corrected data set because of their linearity. Our study adopts two frameworks, based on the Fisher z ‐transformation and bootstrapping, to provide 95% lower and upper confidence limits (referred as the permissible bound) for the GCM cross‐correlation. Beyond the permissible bound, raw/bias‐corrected GCM cross‐correlation significantly differs from those observed. Two frameworks are applied on three GCMs from the CMIP5 multimodel ensemble over the coterminous United States. We found that (a) the univariate linear techniques fail to reproduce the observed cross‐correlation in the bias‐corrected data set over 90% (30–50%) of the grid points where the multivariate skewness coefficient values are substantial (small) and statistically significant (statistically insignificant) from zero; (b) the performance of the univariate linear techniques under bootstrapping (Fisher z ‐transformation) remains uniform (non‐uniform) across climate regions, months, and GCMs; (c) grid points, where the observed cross‐correlation is statistically significant, witness a failure fraction of around 0.2 (0.8) under the Fisher z ‐transformation (bootstrapping). The importance of reproducing cross‐correlations is also discussed along with an enquiry into the multivariate approaches that can potentially address the bias in yielding cross‐correlations. DA - 2019/4/16/ PY - 2019/4/16/ DO - 10.1002/joc.6086 VL - 39 IS - 11 SP - 4479-4496 J2 - Int J Climatol LA - en OP - SN - 0899-8418 1097-0088 UR - http://dx.doi.org/10.1002/joc.6086 DB - Crossref KW - bias correction KW - bootstrapping KW - cross-correlation KW - Fisher z-transformation KW - precipitation KW - temperature KW - univariate ER - TY - JOUR TI - Seismic Repair of Circular Reinforced Concrete Bridge Columns by Plastic Hinge Relocation with Grouted Annular Ring AU - Krish, Zachary F. AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - Journal of Earthquake Engineering AB - Modern seismic design practice for bridge structures involves the implementation of capacity design principles which localize plastic hinges in columns, while protecting against other modes of failure. The resulting structures are capable of reliably sustaining far greater deformations than their predecessors; however, despite their initial resilience, the formation of plastic hinges can result in buckling and rupture of longitudinal steel, typically leading to the structure’s demolition and reconstruction. Replacement is deemed necessary since the inelastic strain capacity of reinforcing bars severely diminishes once buckling occurs, rendering the structure vulnerable to collapse in future earthquakes. Recent research demonstrates the feasibility of a repair technique in which the previously damaged region is strengthened such that future inelastic action occurs at a new location, although there are presently a limited number of tests on which to base reliable design recommendations. Results of an experimental program are presented in this paper, in which six extensively damaged columns are repaired using the plastic hinge relocation technique and retested. The proposed repair strategy consists of a grouted annular ring composed of conventional materials (i.e. steel rebar, a steel sleeve, and concrete or grout). The results substantiate plastic hinge relocation as a viable repair option for columns with buckled and fractured longitudinal bars and serve to expand the existing data set considerably. A novel analytical model which accurately predicts the behavior of the repaired column is also presented. DA - 2019/11/25/ PY - 2019/11/25/ DO - 10.1080/13632469.2019.1688205 SP - 1-35 J2 - Journal of Earthquake Engineering LA - en OP - SN - 1363-2469 1559-808X UR - http://dx.doi.org/10.1080/13632469.2019.1688205 DB - Crossref KW - Plastic hinge relocation KW - repair KW - RC bridge column KW - earthquake KW - traditional materials KW - fractured bars KW - buckled bars KW - analytical model ER - TY - JOUR TI - 1,4-Dioxane in drinking water: emerging for 40 years and still unregulated AU - McElroy, Amie C. AU - Hyman, Michael R. AU - Knappe, Detlef R.U. T2 - Current Opinion in Environmental Science & Health AB - The likely human carcinogen 1,4-dioxane was first detected in drinking water more than 40 years ago, and a recent analysis suggests that almost 30 million people in the United States receive drinking water with 1,4-dioxane levels above the health-based reference concentration of 0.35 μg/L. The widespread occurrence of 1,4-dioxane has exposed the need for developing and implementing management and treatment approaches that protect drinking water sources and prevent human exposure to 1,4-dioxane through drinking water. In this review, we highlight recent advances in analytical methods, understanding of occurrence, and treatment processes. Findings are discussed in the context of managing 1,4-dioxane as a drinking water contaminant, and recommendations are made to address important knowledge gaps. DA - 2019/2// PY - 2019/2// DO - 10.1016/j.coesh.2019.01.003 VL - 7 SP - 117-125 J2 - Current Opinion in Environmental Science & Health LA - en OP - SN - 2468-5844 UR - http://dx.doi.org/10.1016/j.coesh.2019.01.003 DB - Crossref ER - TY - JOUR TI - Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells AU - Ortiz-Medina, Juan F. AU - Grunden, Amy M. AU - Hyman, Michael R. AU - Call, Douglas F. T2 - ACS Sustainable Chemistry & Engineering AB - Ammonia (NH3) is an important industrial chemical that is produced using the energy- and carbon-intensive Haber-Bosch process. Recovering NH3 from microorganisms that fix nitrogen gas (N2) may provide a sustainable alternative because their specialized nitrogenase enzymes can reduce N2 to ammonium (NH4+) without the need for high temperature and pressure. This study explored the possibility of converting N2 into NH4+ using anaerobic, single-chamber microbial electrolysis cells (MECs). N2 fixation rates [based on an acetylene gas (C2H2) to ethylene gas (C2H4) conversion assay] of a microbial consortium increased significantly when the applied voltage between the anode and cathode increased from 0.7 to 1.0 V and reached a maximum of ∼40 nmol of C2H4 min–1 mg protein–1, which is comparable to model aerobic N2-fixing bacteria. The presence of NH4+, which can inhibit the activity of the nitrogenase enzyme, did not significantly reduce N2 fixation rates. Upon addition of methionine sulfoximine, an NH4+ uptake inhibitor, NH4+ was recovered at rates approaching 5.2 × 10–12 mol of NH4+ s–1 cm–2 (normalized to the anode surface area). Relative to the electrical energy consumed, the normalized energy demand [MJ mol–1 (NH4+)] was negative because of the energy-rich methane gas recovered in the MEC. Including the substrate energy resulted in total energy demands as low as 24 MJ mol–1. Community analysis results of the anode biofilms revealed that Geobacter species predominated in both the presence and absence of NH4+, suggesting that they played a key role in current generation and N2 fixation. This study shows that MECs may provide a new route for generating NH4+. DA - 2019/1// PY - 2019/1// DO - 10.1021/acssuschemeng.8b05763 VL - 7 IS - 3 SP - 3511-3519 J2 - ACS Sustainable Chem. Eng. LA - en OP - SN - 2168-0485 2168-0485 UR - http://dx.doi.org/10.1021/acssuschemeng.8b05763 DB - Crossref KW - Nitrogen fixation KW - Ammonium production KW - Haber-Bosch KW - Microbial electrochemical technology KW - Geobacter ER - TY - JOUR TI - A method to select general circulation models for pavement performance evaluation AU - Underwood, B. Shane T2 - International Journal of Pavement Engineering AB - Studies to understand the role of future climate on transportation infrastructure may use climate multiple models and interpret the results based on the statistical variation in simulated outcomes. Unfortunately, specific guidance on the models to choose that ensure results span the breadth of possible outcomes is limited, and the solution involves running simulations using as many models as possible. The objective of this study is to provide guidance on which models from the Coupled Intercomparison Project 5 (CMIP5) dataset to use for pavement studies in the United States and in so doing provide a framework for selecting models from other datasets and locations. Effective temperature functions are derived and used to select individual models from the CMIP5 dataset that represent the maximum, median, and minimum outcomes of the whole ensemble. The results are clustered based on region and represent relatively hot, cold, and median future assumptions. The model selection process is verified using detailed pavement analyses with all models at individual pavement sites in four states. The models chosen using the effective temperature approach are found to align with the extremes and the median, with further improvements to median estimates obtained by averaging all three (maximum, minimum, and median) models. DA - 2019/2/26/ PY - 2019/2/26/ DO - 10.1080/10298436.2019.1580365 SP - 1-13 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2019.1580365 DB - Crossref KW - Pavement performance KW - climate change KW - model selection KW - effective temperature ER - TY - JOUR TI - Dynamic modelling of the iron deficiency modulated transcriptome response in Arabidopsis thaliana roots AU - Koryachko, Alexandr AU - Matthiadis, Anna AU - Haque, Samiul AU - Muhammad, Durreshahwar AU - Ducoste, Joel J AU - Tuck, James M AU - Long, Terri A AU - Williams, Cranos M T2 - in silico Plants AB - The iron deficiency response in plants is a complex biological process with a host of influencing factors. The ability to precisely modulate this process at the transcriptome level would enable genetic manipulations allowing plants to survive in nutritionally poor soils and accumulate increased iron content in edible tissues. Despite the collected experimental data describing different aspects of the iron deficiency response in plants, no attempts have been made towards aggregating this information into a descriptive and predictive model of gene expression changes over time. We formulated and trained a dynamic model of the iron deficiency induced transcriptional response in Arabidopsis thaliana. Gene activity dynamics were modelled with a set of ordinary differential equations that contain biologically tractable parameters. The trained model was able to capture and account for a significant difference in mRNA decay rates under iron sufficient and iron deficient conditions, approximate the expression behaviour of currently unknown gene regulators, unveil potential synergistic effects between the modulating transcription factors and predict the effect of double regulator mutants. The presented modelling approach illustrates a framework for experimental design, data analysis and information aggregation in an effort to gain a deeper understanding of various aspects of a biological process of interest. DA - 2019/1/1/ PY - 2019/1/1/ DO - 10.1093/insilicoplants/diz005 VL - 1 IS - 1 LA - en OP - SN - 2517-5025 UR - http://dx.doi.org/10.1093/insilicoplants/diz005 DB - Crossref KW - Arabidopsis thaliana KW - modelling KW - ODE KW - Gene Regulatory Network KW - plant stress response ER - TY - JOUR TI - Cooperative traffic signal and perimeter control in semi-connected urban-street networks AU - Mohebifard, Rasool AU - Islam, S.M.A. Bin Al AU - Hajbabaie, Ali T2 - Transportation Research Part C: Emerging Technologies AB - This paper presents an integrated formulation and a distributed solution technique for cooperative signal control and perimeter traffic metering in urban street networks with various market penetration rates of connected vehicles. The problem is formulated as a mixed integer nonlinear program thus, does not scale well with the size of the network in a centralized optimization framework due to the presence of many mixed integer decision variables and nonlinear constraints. To address this limitation, we will develop a distributed model predictive control that distributes the network-level cooperative problem into several intersection-level sub-problems and coordinates their decisions. Our numerical analyses show that the proposed distributed methodology finds solutions to the problem in real-time with the optimality gap of at most 3.6% in our case studies. We have implemented the distributed methodology in Vissim and observed that cooperative signal timing and perimeter control yielded significant improvements in traffic operations. Our case study results show that the cooperative approach increases the number of completed trips by 6.0–12.8% and 10.9–11.0% and reduces the total travel times by 8.1–9.0% and 23.6–24.2% compared to independent signal control and independent perimeter control, respectively. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.trc.2019.05.023 VL - 104 SP - 408-427 UR - https://doi.org/10.1016/j.trc.2019.05.023 KW - Cooperative traffic control KW - Traffic signal optimization KW - Perimeter control KW - Distributed optimization and coordination algorithms KW - Connected vehicles ER - TY - JOUR TI - Metamodels to assess the thermal performance of naturally ventilated, low-cost houses in Brazil AU - Rossi, Michele Marta AU - Oliveira Favretto, Ana Paula AU - Grassi, Camila AU - DeCarolis, Joseph AU - Cho, Soolyeon AU - Hill, David AU - Soares Chvatal, Karin Maria AU - Ranjithan, Ranji T2 - ENERGY AND BUILDINGS AB - Building performance simulation [BPS] tools are important in all design stages. However, barriers such as time, resources, and expertise inhibit their use in the early design stages. This study aims to develop, as part of decision-support framework, metamodels to assess the thermal discomfort in a naturally ventilated Brazilian low-cost house during early design. The metamodels predict the degree-hours of discomfort by heat and/or by cold as a function of design parameters for three Brazilian cities: Curitiba, São Paulo, and Manaus. The key design parameters, related with passive design strategies, are building orientation, shading devices position and dimensions, thermal properties of the walls and roof, window-to-wall ratio, and effective window ventilation area. The method consists of three main stages: (i) baseline model development; (ii) Monte Carlo simulation; (iii) multivariate regression. Overall, the metamodels showed R2 values higher than 0.95 for all climates, except the ones predicting discomfort by heat for Curitiba (R2 =0.61) and São Paulo (R2 =0.75). The proposed metamodels can quickly and accurately assess the thermal performance of naturally ventilated low-cost houses. They can be used to guide professionals during the early design stages, and for educational purposes in building design pedagogy. DA - 2019/12/1/ PY - 2019/12/1/ DO - 10.1016/j.enbuild.2019.109457 VL - 204 SP - SN - 1872-6178 KW - Passive design KW - Natural ventilation KW - Metamodel KW - Multivariate regression KW - Early design ER - TY - JOUR TI - Fate of Per- and Polyfluoroalkyl Ether Acids in the Total Oxidizable Precursor Assay and Implications for the Analysis of Impacted Water AU - Zhang, Chuhui AU - Hopkins, Zachary R. AU - McCord, James AU - Strynar, Mark J. AU - Knappe, Detlef R. U. T2 - Environmental Science & Technology Letters AB - Per- and polyfluoroalkyl substances (PFASs) are widely used anthropogenic chemicals. The PFAS class includes almost 5000 registered compounds, but analytical methods are lacking for most PFASs. The total oxidizable precursor (TOP) assay was developed to indirectly quantify unknown PFASs that are precursors to commonly measured perfluoroalkyl acids. To understand the behavior of recently identified per- and polyfluoroalkyl ether acids (PFEAs), including fluorinated replacements and manufacturing byproducts, we determined the fate of 15 PFEAs in the TOP assay. Ten perfluoroalkyl ether acids and a chlorinated polyfluoroalkyl ether acid (F-53B) were stable in the TOP assay and represent terminal products that are likely as persistent as historically used PFASs. Adding perfluoroalkyl ether acids and F-53B to the target analyte list for the TOP assay is recommended to capture a higher percentage of the total PFAS concentration in environmental samples. In contrast, polyfluoroalkyl ether acids with a -O-CFH- moiety were oxidized, typically to products that could not be identified by liquid chromatography and high-resolution mass spectrometry. Application of the TOP assay in its proposed enhanced form revealed high levels of PFEAs, the presence of precursors that form perfluoroalkyl carboxylic acids, and the absence of precursors that form PFEAs in surface water impacted by PFAS-containing wastewater discharges. DA - 2019/10/2/ PY - 2019/10/2/ DO - 10.1021/acs.estlett.9b00525 VL - 6 IS - 11 SP - 662-668 J2 - Environ. Sci. Technol. Lett. LA - en OP - SN - 2328-8930 2328-8930 UR - http://dx.doi.org/10.1021/acs.estlett.9b00525 DB - Crossref ER - TY - JOUR TI - Assessing potential anthropogenic drivers of ecological health in Piedmont streams through hierarchical modeling AU - Miller, Jonathan W. AU - Paul, Michael J. AU - Obenour, Daniel R. T2 - FRESHWATER SCIENCE AB - Urban streams consistently have poorer ecological condition than natural streams. Poor ecological condition is caused by a myriad of anthropogenic impacts that alter hydrology and increase pollutant concentrations. Urban streams are monitored frequently, but viable management options for improving stream condition are ill-defined. A more complete understanding of the factors that influence biological condition, as well the ability to identify sites that deviate from expected condition, would help managers develop more efficient stream restoration strategies. Here, we use a hierarchical (multilevel) framework to model >3000 macroinvertebrate samples from the North Carolina Piedmont region, identify important natural gradients and anthropogenic factors that relate to stream condition, and demonstrate how hierarchical modeling can help identify potential restoration sites. In addition, we explore spatial (e.g., watershed versus stream buffer) and temporal (e.g., age of construction) aspects of land cover development. We found that watershed impervious cover (IC) is the best predictor of biotic index (BI) values. Additional factors significantly related to BI include age of watershed IC, canopy loss in stream buffers, reservoirs, wastewater treatment plants, antecedent precipitation, and geologic soil types. Synthesizing these factors in a hierarchical multiple linear regression model explained 76% of the variability (R2) in the BI, relative to 65% with only watershed IC. Of the remaining variability in the observations (24%), most was accounted for by site-specific random effects (16%), which characterize the deviation between predicted and actual biological condition. The model also suggests that newer development (post-1980) degrades stream health 30% less than older development. Additionally, canopy removal in stream buffers had 2 to 9× the effect on BI relative to the addition of IC in upstream watersheds on a per hectare basis. DA - 2019/12/1/ PY - 2019/12/1/ DO - 10.1086/705963 VL - 38 IS - 4 SP - 771-789 SN - 2161-9565 KW - biological assessment KW - anthropogenic stressors KW - watershed development KW - stream restoration KW - stream buffers KW - mixed-effects models KW - macroinvertebrates ER - TY - JOUR TI - Investigating challenges of in situ delivery of microbial-induced calcium carbonate precipitation (MICP) in fine-grain sands and silty sand AU - Zamani, Atefeh AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - Canadian Geotechnical Journal AB - Microbial-induced calcium carbonate precipitation (MICP) is a sustainable soil improvement method with the potential for improving the engineering properties of sand and silty soils and therefore their resistance to liquefaction-inducing events. Work presented herein experimentally investigates the changes in hydraulic conductivity of fine sands and silty sands as a result of MICP treatment. In addition, numerical modeling is conducted to assess the changes in allowable injection rate and radius of influence for the delivery of the MICP process at the field scale. The hydraulic conductivity of Nevada sand and silty sand with 15% fines content decreased through MICP application with the trend of reduction being similar for both soils. Numerical modeling results show that with the progress of the MICP process, injection rates can be increased for Nevada sand, but remain unchanged for Nevada sand with 15% silt content (after MICP treatment up to a shear wave velocity about 400 m/s.) The presence of fines by itself leads to generation of higher levels of pore-water pressure during the injection process, which necessitates higher strength improvement to prevent development of excessive plastic strains. Therefore, improvement in shear strength and stiffness relative to the magnitude of the hydraulic conductivity level and its rate of change during the MICP process is a key parameter in determining the radius of treatment. DA - 2019/12// PY - 2019/12// DO - 10.1139/cgj-2018-0551 VL - 56 IS - 12 SP - 1889-1900 J2 - Can. Geotech. J. LA - en OP - SN - 0008-3674 1208-6010 UR - http://dx.doi.org/10.1139/cgj-2018-0551 DB - Crossref KW - cemented silty sand KW - shear wave velocity KW - microbial-induced calcium carbonate precipitation KW - Sporocarcina pasteurii KW - injection rate KW - injection pressures ER - TY - JOUR TI - Subgrid theory for storm surge modeling AU - Kennedy, Andrew B. AU - Wirasaet, Damrongsak AU - Begmohammadi, Amirhosein AU - Sherman, Thomas AU - Bolster, Diogo AU - Dietrich, J.C. T2 - Ocean Modelling AB - Averaging techniques are used to generate upscaled forms of the shallow water equations for storm surge including subgrid corrections. These systems are structurally similar to the standard shallow water equations but have additional terms related to integral properties of the fine-scale bathymetry, topography, and flow. As the system only operates with coarse-scale variables (such as averaged fluid velocity) relating to flow, these fine-scale integrals require closures to relate them to the coarsened variables. Closures with different levels of complexity are identified and tested for accuracy against high resolution solutions of the standard shallow water equations. Results show that, for coarse grids in complex geometries, inclusion of subgrid closure terms greatly improves model accuracy when compared to standard solutions, and will thereby enable new classes of storm surge models. DA - 2019/12// PY - 2019/12// DO - 10.1016/j.ocemod.2019.101491 VL - 144 SP - 101491 J2 - Ocean Modelling LA - en OP - SN - 1463-5003 UR - http://dx.doi.org/10.1016/j.ocemod.2019.101491 DB - Crossref KW - Subgrid methods KW - Storm surge KW - Numerical methods KW - Mathematical modeling KW - Shallow water equations ER - TY - JOUR TI - Farewell AU - Gabr, Mohammed T2 - Journal of Geotechnical and Geoenvironmental Engineering DA - 2019/5// PY - 2019/5// DO - 10.1061/(ASCE)GT.1943-5606.0002076 UR - https://doi.org/10.1061/(ASCE)GT.1943-5606.0002076 ER - TY - JOUR TI - Coupled analysis for response and instability of sloping seabed under wave action AU - Rafiei, Amin AU - Rahman, M.S. AU - Gabr, M.A. T2 - Applied Ocean Research AB - Wave-induced instability of seabed may cause damage to coastal and offshore structures. This issue has been investigated mostly for mildly sloping (<5°) seabed considering uncoupled or one-way coupled response of wave and seabed interaction. However, some of the marine structures are founded on seabed with steeper slopes. In this study, the wave-induced response and instability of sloping seabed are evaluated using a coupled finite element model. The interaction between fluid and porous seabed accounting for the effect of fluid motion on the seabed response, and conversely the effect of seabed response on the fluid motion (but not on the surface wave profile) is considered. The results indicate that the system response (fluid pressure, stresses, etc.) and the extent of instantaneously liquefied zone within the sloping seabed with significant steepness are lesser than those for horizontal seabed. Moreover, for typical sediment and wave characteristics, for the flat seabed, the response obtained from fully coupled analysis is not significantly different from those obtained by uncoupled analysis. For the sloping bed, such difference is slightly greater as compared to that for the flat bed. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.apor.2019.04.017 VL - 88 SP - 99-110 UR - https://doi.org/10.1016/j.apor.2019.04.017 KW - Wave-seabed interaction KW - Slope instability KW - Liquefaction analysis KW - Finite element analysis ER - TY - JOUR TI - Gradient-based hybrid topology/shape optimization of bioinspired microvascular composites AU - Pejman, Reza AU - Aboubakr, Sherif H. AU - Martin, William H. AU - Devi, Urmi AU - Tan, Marcus Hwai Yik AU - Patrick, Jason F. AU - Najafi, Ahmad R. T2 - INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER AB - Construction of bioinspired vasculature in synthetic materials enables multi-functional performance via mass transport through internal fluidic networks. However, exact reproduction of intricate, natural microvascular architectures is nearly impossible and thus there is a need to create practical, manufacturable designs guided by multi-physics principles. Here we present a Hybrid Topology/Shape (HyTopS) optimization scheme for microvascular materials using the Interface-enriched Generalized Finite Element Method (IGFEM). This new approach, which can simultaneously perform topological changes as well as shape optimization of microvascular materials, is demonstrated in the context of thermal regulation. In the current study, we present a new feature that enables the optimizer to augment network topology by creating/removing microchannels during the shape optimization process. This task has been accomplished by introducing a new set of design parameters, which act analogous to the penalization factor in the Solid Isotropic Material with Penalization (SIMP) method. The analytical sensitivity for the HyTopS optimization scheme has been derived and the sensitivity accuracy is verified against the finite difference method. We impose a set of geometrical constraints to account for manufacturing limitations and produce a design which is suitable for large-scale production without the need to perform post-processing on the obtained optimum. The method is validated by active-cooling experiments on vascularized carbon-fiber composites. Finally, we compare various application examples to demonstrate the advantages of the newly introduced HyTopS optimization scheme over solely shape optimization for microvascular materials. DA - 2019/12// PY - 2019/12// DO - 10.1016/j.ijheatmasstransfer.2019.118606 VL - 144 SP - SN - 1879-2189 KW - Hybrid topology/shape optimization KW - Interface-enriched generalized finite element method KW - Microvascular composites KW - Active-cooling KW - 3D printing ER - TY - JOUR TI - Investigation and modelling of greenhouse gas emissions resulting from waste collection and transport activities AU - Yaman, Cevat AU - Anil, Ismail AU - Jaunich, Megan K. AU - Blaisi, Nawaf I. AU - Alagha, Omar AU - Yaman, Ayse B. AU - Gunday, Seyda T. T2 - WASTE MANAGEMENT & RESEARCH AB - Greenhouse gas emissions resulting from municipal solid waste management activities and the associated climate change impacts are getting great attention worldwide. This study investigates greenhouse gas emissions and their distribution during waste collection and transport activities in the Dammam region of Saudi Arabia. Greenhouse gas emissions and associated global warming factors were estimated based on diesel fuel consumption during waste collection and transport activities. Then, waste collection and transport data were used to parameterise a mechanistic collection model that can be used to estimate and predict future fuel consumption and greenhouse gas emissions. For the collection and transport of municipal waste in the study area, the average associated total greenhouse gas emissions were about 24,935 tCO 2 -eq. Global warming factors for three provinces were estimated as 25.23 kg CO 2 -eq t -1 , 25.04 kg CO 2 -eq t -1 , and 37.15 kg CO 2 -eq t -1 , respectively. Lastly, the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) modelling system was used to estimate the atmospheric dispersion of greenhouse gas emissions. Model results revealed that the maximum daily greenhouse gas concentrations ranged between 0.174 and 97.3 mg m -3 , while annual average greenhouse gas concentrations were found to be between 0.012 and 27.7 mg m -3 within the study domain. The highest greenhouse gas concentrations were observed for the regions involving the municipal solid waste collection routes owing to their higher source emission rates. DA - 2019/12// PY - 2019/12// DO - 10.1177/0734242X19882482 VL - 37 IS - 12 SP - 1282-1290 SN - 1096-3669 KW - Greenhouse gas KW - waste KW - collection KW - transfer KW - AERMOD KW - global warming factor ER - TY - JOUR TI - Evaluation of fatigue cracking performance in a debonded asphalt pavement T2 - International Journal of Pavement Research and Technology DA - 2019/7// PY - 2019/7// DO - 10.1007/s42947-019-0046-8 UR - http://dx.doi.org/10.1007/s42947-019-0046-8 ER - TY - CHAP TI - Systems and Methods for Studying Microbial Processes and Communities in Landfills AU - Weaver, Joseph E. AU - Wang, Ling AU - de los Reyes, Francis L., III AU - Barlaz, Morton A. T2 - Advances in Environmental Microbiology PY - 2019/// DO - 10.1007/978-3-030-10777-2_5 SP - 129-150 OP - PB - Springer International Publishing SN - 9783030107758 9783030107772 UR - http://dx.doi.org/10.1007/978-3-030-10777-2_5 DB - Crossref ER - TY - JOUR TI - Survey Comparing Critical Path Method, Last Planner System, and Location-Based Techniques AU - Olivieri, Hylton AU - Seppanen, Olli AU - Alves, Thais da C. L. AU - Scala, Natalie M. AU - Schiavone, Vincent AU - Liu, Min AU - Granja, Ariovaldo Denis T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - In construction, the most relevant systems used for project management (PM) and project production management (PPM) in the planning and control phases are critical path method (CPM), last planner system (LPS), and location-based techniques (LB). Studies have addressed these systems, mostly in isolated fashions. This study aims to compare and contrast their use in terms of PM and PPM and clarify industry benefits in order to eliminate potential misunderstandings about their use. A survey was administered to construction professionals in Brazil, China, Finland, and the United States. No single system addresses all needs of PM and PPM. CPM is the dominant system when considering the following characteristics: primary industry types, type of organization, size of organization, professional position within the organization, and area of work. Contributions to knowledge include that CPM is a contract requirement with perceived benefits associated with critical path analysis; LB and LPS have perceived benefits regarding continuous flow and use of resources, treatment of interferences, and improving production control. All systems were found to have a similar level of benefits for management of contracts, delay and change, and evaluation of the root causes of delays. The industry can benefit from aligning project scheduling methods with project needs. DA - 2019/12/1/ PY - 2019/12/1/ DO - 10.1061/(ASCE)CO.1943-7862.0001644 VL - 145 IS - 12 SP - SN - 1943-7862 KW - Construction KW - Scheduling KW - Critical path method KW - Last planner system KW - Location-based systems ER - TY - JOUR TI - Construction Safety Culture and Climate: Satisfying Necessity for an Industry Framework AU - Al-Bayati, Ahmed Jalil AU - Albert, Alex AU - Ford, George T2 - PRACTICE PERIODICAL ON STRUCTURAL DESIGN AND CONSTRUCTION AB - Much of the construction literature that examines safety culture and safety climate ignores the unique characteristics of construction workplaces. Therefore, existing safety culture and climate models do not capture the true nature of construction practices where the upper management, such as project managers and safety coordinators, often manage several construction projects. Accordingly, a framework that addresses the contribution of the management personnel as well as the site-level personnel has been presented as part of the current research. The proposed framework captures safety culture and safety climate using the following two distinct factors: (1) the management safety (MS) factor and (2) the site safety (SS) factor. A survey was administered to collect the perceptions of construction practitioners and site personnel regarding the suggested variables of the MS and SS factors. In addition, the experience modification rate (EMR) was collected to assess the relation between the suggested model and the overall safety performance. The results obtained provide support for the proposed model by suggesting that the MS factor significantly influences the SS factor and that the two factors are negatively associated with the EMRs of the participating organizations. Furthermore, the findings suggest that the MS factor represents the construction safety culture and the SS represents the construction safety climate. DA - 2019/11// PY - 2019/11// DO - 10.1061/(ASCE)SC.1943-5576.0000452 VL - 24 IS - 4 SP - SN - 1943-5576 ER - TY - PCOMM TI - Moving towards transformational WASH AU - Kearns, Josh AB - As noted by the Lancet Commission on pollution and health,1Landrigan PJ Fuller R Acosta NJR et al.The Lancet Commission on pollution and health.Lancet. 2018; 391: 462-512Summary Full Text Full Text PDF PubMed Scopus (1280) Google Scholar the anthropogenic release of chemicals from industry and agriculture and the breakdown of consumer waste constitutes a major threat to water and global public health. Chemical pollution is severe and increasing in developing countries, where chemical substances are produced, used, and disposed of in an unregulated manner. The global public health consequences of pollution are similar to or greater than those of widespread infectious diseases, such as HIV/AIDS, tuberculosis, and malaria.1Landrigan PJ Fuller R Acosta NJR et al.The Lancet Commission on pollution and health.Lancet. 2018; 391: 462-512Summary Full Text Full Text PDF PubMed Scopus (1280) Google Scholar, 2Landrigan PJ Fuller R Pollution, health and development: the need for a new paradigm.Rev Environ Health. 2016; 31: 121-124Crossref PubMed Scopus (2) Google Scholar However, chemicals have so far been neglected by the water, sanitation, and hygiene (WASH) development sector. Amy Pickering and colleagues3Pickering AJ Null C Winch PJ et al.The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoea.Lancet Glob Health. 2019; 7: e1139-e1146Summary Full Text Full Text PDF PubMed Scopus (89) Google Scholar analyse the recent WASH Benefits trials and the Sanitation, Hygiene, Infant Nutrition Efficacy (SHINE) trial, in Bangladesh, Kenya, and Zimbabwe, which revealed that household WASH interventions are unlikely to reduce diarrhoea or improve child growth. One explanation for why WASH interventions have failed to produce health benefits is that WASH interventions control for pathogens but not chemicals. Exposure to many synthetic chemicals can dysregulate immune function in ways that lead not only to increased vulnerability to non-communicable diseases, such as cancer, but also to greater susceptibility to pathogens and reduced effectiveness of vaccinations against infectious diseases.4Winans B Humble MC Lawrence BP Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?.Reprod Toxicol. 2011; 31: 327-336Crossref PubMed Scopus (76) Google Scholar, 5Erickson BE Linking pollution and infectious disease: chemicals and pathogens interact to weaken the immune system, reduce vaccine efficacy, and increase pathogen virulence.Chem Eng News. 2019; 97: 28-33Google Scholar For example, immunotoxicity has been demonstrated for several compound classes, including halogenated organics, plasticisers such as phthalates and bisphenol-A, numerous pesticides including atrazine and chlordane, flame retardants, and per-fluoroalkyl and poly-fluoroalkyl substances (PFAS).4Winans B Humble MC Lawrence BP Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?.Reprod Toxicol. 2011; 31: 327-336Crossref PubMed Scopus (76) Google Scholar, 5Erickson BE Linking pollution and infectious disease: chemicals and pathogens interact to weaken the immune system, reduce vaccine efficacy, and increase pathogen virulence.Chem Eng News. 2019; 97: 28-33Google Scholar Therefore, WASH interventions that do not control for chemicals in addition to pathogens might fail to achieve gains in health indicators associated with waterborne disease. The WASH sector has yet to recognise and grapple with the challenge of mitigating threats to health from chemical toxicants in water. For example, Pickering and colleagues make recommendations for improving WASH interventions, but do not mention chemicals. There is an urgent need for WASH to move beyond the current, limited focus on microbial pathogens, towards a holistic approach to water and health in developing countries that takes chemicals into account. As a step to address this challenge, some colleagues and I have formed the WASH-Toxics Working Group. I declare no competing interests. The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoeaChild stunting is a global problem and is only modestly responsive to dietary interventions. Numerous observational studies have shown that water quality, sanitation, and handwashing (WASH) in a household are strongly associated with linear growth of children living in the same household. We have completed three randomised efficacy trials testing improved household-level WASH with and without improved infant and young child feeding (IYCF) on stunting and diarrhoea in Bangladesh, Kenya, and Zimbabwe. Full-Text PDF Open AccessMoving towards transformational WASH – Authors' replyWe agree with Karen Levy and Joseph Eisenberg that observational studies of water, sanitation, and hygiene (WASH) interventions with carefully designed counterfactuals can play a valuable role in generating evidence on effectiveness, particularly in urban settings. Randomised controlled trials for community-level WASH infrastructure interventions are not always feasible in urban settings, because of the political and logistical constraints of defining treatment and control groups; strong observational designs could help fill the gap. Full-Text PDF Open AccessMoving towards transformational WASHThe observational reanalysis by Amy Pickering and colleagues (August, 2019)1 of controls in the WASH Benefits trials and the Sanitation, Hygiene, Infant Nutrition Efficacy (SHINE) trial is a compelling reminder that observational studies are susceptible to confounding bias. However, we should not discount the value of observational studies in global health research, because ethical and logistical issues often limit the feasibility of randomised control trials (RCTs) and observational studies are a requisite precursor to trials. Full-Text PDF Open Access DA - 2019/11// PY - 2019/11// DO - 10.1016/S2214-109X(19)30394-8 SP - E1493-E1493 ER - TY - JOUR TI - Expansive soil modified by waste steel slag and its application in subbase layer of highways AU - Wu, Jun AU - Liu, Qianwen AU - Deng, Yongfeng AU - Yu, Xinbao AU - Feng, Qi AU - Yan, Chao T2 - SOILS AND FOUNDATIONS AB - Steel slag is a waste by-product of the steel industry. The recycling usage of steel slag is limited due to the mutative chemical compositions it contains and its low cementation. In this investigation, the composition adjustment and activation of steel slag were studied to produce an optimal slag-based composite with improved cementation efficiency. The controlling moduli of cement clinker were introduced to standardise the composite. Subsequently, the composite was used to modify Hefei expansive soil (a kind of engineering waste for swelling properties) in embankment construction. The basic physical properties including free swelling ratio, California bearing ratio, unconfined compressive strength, microstructure, and mineral evolution were evaluated to understand the engineering performance and mechanism of modified expansive soils. The results show that the cementation of the slag was significantly improved after the composition adjustment and activation. Furthermore, the treated soil can satisfy the requirement of the Chinese standard for first-class road/highway when the composite incorporation ratio is more than 5%. The microstructural and mineralogical analysis shows that the component adjustment and activation enrich the cementation of the slag, resulting in the suppression of the swelling potential and improved strength. The above findings improve the reuse efficiency of steel slag, especially in expansive soil modifications. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.sandf.2019.03.009 VL - 59 IS - 4 SP - 955-965 SN - 0038-0806 KW - Steel slag KW - Component adjustment and activation KW - Expansive soil KW - Subbase performance KW - Microstructure ER - TY - JOUR TI - Improving monthly streamflow forecasts through assimilation of observed streamflow for rainfall-dominated basins across the CONUS AU - Mazrooei, Amirhossein AU - Sankarasubramanian, A. T2 - Journal of Hydrology AB - Among different sources of uncertainty in hydrologic modeling (i.e., model structure, parameter estimation, input data, etc.), consecutive error reduction of model initial conditions can prevent a model from drifting away from reality and consequently improving model estimates. Most approaches that evaluated the correction of initial conditions through data assimilation (DA) have focused on improving hydrologic model simulations (i.e., under observed forcings) rather than evaluating the model performance in a forecasting context. This paper investigates the utility of Ensemble Kalman Filter (EnKF) data assimilation in which available observed streamflow is exploited to update state variables of a conceptual water balance model for forecasting monthly streamflow over 340 rainfall-dominated river basins across the contiguous United States (CONUS). Our results demonstrate that after EnKF application, streamflow simulation skill improves in terms of both Relative Root Mean Square Error (R-RMSE) and correlation coefficient (CC) for almost 90% of the selected river basins. Evaluating the model performance under different flow conditions shows that EnKF has stronger positive effect on monthly low flow predictions comparing to monthly high flows particularly during the summer season. The utility of EnKF is also assessed in the context of 1-month ahead streamflow forecasting. Due to the updated model initial conditions, streamflow forecasts are improved throughout the year even though the skill in hydrologic forecasts is predominantly dependent on the accuracy of precipitation forecasts. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.jhydrol.2019.05.071 VL - 575 SP - 704-715 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/j.jhydrol.2019.05.071 DB - Crossref KW - Streamflow forecasting KW - Hydrologic data assimilation KW - Conceptual water balance model ER - TY - JOUR TI - Characterizing Lane Changes via Digitized Infrastructure and Low-Cost GPS AU - Ahmed, Ishtiak AU - Karr, Alan AU - Rouphail, Nagui M. AU - Chun, Gyounghoon AU - Tanvir, Shams T2 - TRANSPORTATION RESEARCH RECORD AB - With the expected increase in the availability of trajectory-level information from connected and autonomous vehicles, issues of lane changing behavior that were difficult to assess with traditional freeway detection systems can now begin to be addressed. This study presents the development and application of a lane change detection algorithm that uses trajectory data from a low-cost GPS-equipped fleet, supplemented with digitized lane markings. The proposed algorithm minimizes the effect of GPS errors by constraining the temporal duration and lateral displacement of a lane change detected using preliminary lane positioning. The algorithm was applied to 637 naturalistic trajectories traversing a long weaving segment and validated through a series of controlled lane change experiments. Analysis of naturalistic trajectory data revealed that ramp-to-freeway trips had the highest number of discretionary lane changes in excess of 1 lane change/vehicle. Overall, excessive lane change rates were highest between the two middle freeway lanes at 0.86 lane changes/vehicle. These results indicate that extreme lane changing behavior may significantly contribute to the peak-hour congestion at the site. The average lateral speed during lane change was 2.7 fps, consistent with the literature, with several freeway–freeway and ramp–ramp trajectories showing speeds up to 7.7 fps. All ramp-to-freeway vehicles executed their first mandatory lane change within 62.5% of the total weaving length, although other weaving lane changes were spread over the entire segment. These findings can be useful for implementing strategies to lessen abrupt and excessive lane changes through better lane pre-positioning. DA - 2019/8// PY - 2019/8// DO - 10.1177/0361198119841277 VL - 2673 IS - 8 SP - 298-309 SN - 2169-4052 ER - TY - JOUR TI - Three-dimensional electrical capacitance tomography - A tool for characterizing moisture transport properties of cement-based materials AU - Voss, Antti AU - Hosseini, Payam AU - Pour-Ghaz, Mohammad AU - Vauhkonen, Marko AU - Seppanen, Aku T2 - MATERIALS & DESIGN AB - Water often plays a major role in the degradation processes of cement-based materials and structures, and thus the durability of these structures strongly depends on their ability to impede transport of water. This paper reports the results of imaging three-dimensional (3D) unsaturated moisture flow in mortar specimens using electrical capacitance tomography (ECT) imaging, which is based on non-intrusive and contact-free capacitance surface measurements. In a series of experiments, three mortar specimens with differing moisture transport properties were imaged with ECT during a 3D ingress of water. For comparison, we also modeled the flow of moisture numerically, by Finite Element Method (FEM) approximation of the 3D equation of unsaturated moisture flow in porous media, commonly referred to as Richard's equation. The ECT reconstructions are in good agreement with the flow model for all specimens which supports the ability of ECT to image 3D water transport in cement-based materials. DA - 2019/11/5/ PY - 2019/11/5/ DO - 10.1016/j.matdes.2019.107967 VL - 181 SP - SN - 1873-4197 KW - Cement-based materials KW - Unsaturated moisture flow KW - Electrical capacitance tomography KW - Imaging KW - Numerical flow model KW - Transport properties ER - TY - JOUR TI - Numerical simulation and experimental corroboration of galvanic corrosion of mild steel in synthetic concrete pore solution AU - Mohammadian, Armita AU - Rashetnia, Reza AU - Lucier, Gregory AU - Seracino, Rudolf AU - Pour-Ghaz, Mohammad T2 - CEMENT & CONCRETE COMPOSITES AB - Corrosion of reinforcing steel in concrete is one of the most prevalent deterioration mechanisms affecting reinforced concrete structures. While there have been significant advances in modeling the initiation stage of corrosion, corrosion kinetic models for predicting the rate of corrosion after depassivation of steel are scarce, and models with experimental corroboration under controlled experimental conditions are virtually nonexistent. Furthermore, the sensitivity of corrosion kinetic models to the uncertainty of their input parameters is not understood. The objective of the present work is to model active corrosion of steel in synthetic solution, experimentally corroborate the modeling approach under controlled conditions, and study the effect of uncertainty of the input parameters on the model predictions. To this end, a two-dimensional finite element method is used to solve the coupled system of Poisson-Nernst-Planck (PNP) equations subjected to electroneutrality constraint. To corroborate the modeling approach, the results of computations are compared against one-dimensional and two-dimensional galvanic corrosion of stainless/carbon steel in dilute and non-dilute NaCl electrolytes as well as two synthetic concrete pore solutions. The modeling parameters, including electrode polarization behaviors and electrolyte properties, are obtained experimentally. Monte Carlo simulations are used to understand the effect of uncertainty of polarization parameters on the predicted corrosion rate. DA - 2019/10// PY - 2019/10// DO - 10.1016/j.cemconcomp.2019.04.027 VL - 103 SP - 263-278 SN - 1873-393X KW - Poisson-Nernst-Planck equations KW - Galvanic corrosion KW - Modeling KW - Monte Carlo simulations KW - Corrosion current density ER - TY - JOUR TI - Optimizing routing and tower spotting of electricity transmission lines: An integration of geographical data and engineering aspects into decision-making AU - Moreira Santos, Afonso Henriques AU - Lima, Rodolfo Mendes AU - Silva Pereira, Camilo Raimundo AU - Osis, Reinis AU - Santos Medeiros, Giulia Oliveira AU - Queiroz, Anderson Rodrigo AU - Flauzino, Barbara Karoline AU - Paschoal Correa Cardoso, Arthur Rohr AU - Czank Junior, Luiz AU - Santos, Renato Antonio AU - Carvalho Junior, Eden Luiz T2 - ELECTRIC POWER SYSTEMS RESEARCH AB - In many parts of the world, electric sectors are already experiencing considerable rising in generation from renewable energy sources. Large amounts of new generation are expected in the near-term future, which will require additional transmission investments to properly integrate these resources into the existing electric power system. The transmission expansion planning has an important role in this environment in order to guarantee the security of the supply with the required levels of quality and price. Therefore, the implementation of new transmission lines (TL) must be fast and accurate in order to avoid delays to connect new power sources and potential supply and reliability problems. In this sense, Geographical Information Systems (GIS) can be a powerful tool that provides decision support techniques, which enables a transparent, sustainable, faster planning process for TLs in power systems. This paper presents a novel approach for the design of overhead TLs, considering geographical, engineering and cost aspects into the decision-making process. For this, routing and tower spotting optimization approaches are integrated into the proposed methodology, which is divided into three main steps: (i) Route Guideline Definition based on a raster-based least-cost path approach; (ii) Vertex Siting based on graph theory and the Dijkstra shortest path algorithm, applied in order to find the optimal vertex set along the route guideline; (iii) Tower Spotting based on Dynamic Programming, which is applied in order to find the optimal distribution of towers along the topographical profile of the route obtained in the previous step. The proposed methodology is focused on preliminary planning and decision-making for TL auctions, where the objective is to find design alternatives with the least cost. We show a case study using the proposed methodology for a real project of a 525 kV TL that interconnects Machadinho and Campos Novos (located in the Santa Catarina state in Brazil). The outcomes show that the proposed approach is capable of representing the technical and geographical constraints of a TL design, providing results with lower costs when compared to the original TL design. DA - 2019/11// PY - 2019/11// DO - 10.1016/j.epsr.2019.105953 VL - 176 SP - SN - 1873-2046 UR - https://doi.org/10.1016/j.epsr.2019.105953 KW - Transmission lines KW - Route guideline KW - Vertex siting KW - Tower spotting KW - Mathematical programming ER - TY - JOUR TI - Volatility and Viscosity Are Correlated in Terpene Secondary Organic Aerosol Formed in a Flow Reactor AU - Champion, Wyatt M. AU - Rothfuss, Nicholas E. AU - Petters, Markus D. AU - Grieshop, Andrew P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS AB - Secondary organic aerosol (SOA) is a complex mixture of largely unspeciated compounds. The volatility and viscosity of the bulk organic aerosol influence new particle formation, processing, and lifetime in the atmosphere. Relationships between these properties are well-defined for pure compounds but currently unavailable for bulk organic aerosol. In this survey study, we characterized SOA formed from a range of biogenic precursors and conditions in an oxidation flow reactor for volatility (thermodenuder), viscosity (dimer coagulation, isolation, and coalescence), and oxidation state (aerosol chemical speciation monitor). We find linear trends in log–linear and log–log plots of single-parameter representations of volatility and viscosity, with higher condensed-phase fractions of extremely low and low volatility material associated with an increased viscosity (R = 0.69). Per this relationship, an increase in the contribution of these fractions (i.e., lower volatility) by 0.1 results in an increase in viscosity of approximately 200%. The viscosity (at 30 °C) of SOA fell between 6.2 × 105 and 8.0 × 108 Pa s and thus in the semisolid range. The SOA oxidation state ranged from −1.0 and 0.1 and was weakly anticorrelated with volatility (but not viscosity). We found larger SOA mass loadings generally associated with increased volatility and decreased viscosity. The results of this preliminary study are consistent with “molecular corridor”-style frameworks employing molecular mass and volatility to estimate the viscosity of bulk real-world SOA. DA - 2019/9// PY - 2019/9// DO - 10.1021/acs.estlett.9b00412 VL - 6 IS - 9 SP - 513-519 SN - 2328-8930 UR - https://doi.org/10.1021/acs.estlett.9b00412 ER - TY - JOUR TI - Evaluation of Fatigue Cracking Resistance of Asphalt Mixtures Using Apparent Damage Capacity AU - Etheridge, Robert Austin AU - Wang, Yizhuang David AU - Kim, S. Sonny AU - Kim, Y. Richard T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - The prediction of fatigue cracking is one of the critical items to assess the service life of flexible pavements. Accordingly, researchers have developed several test methods and index parameters to predict pavement performance based on fatigue damage. Recently, researchers at North Carolina State University developed a new index parameter, referred to as apparent damage capacity (Sapp), which is based on the simplified viscoelastic continuum damage (S-VECD) model. This index parameter is obtained by performing cyclic tension tests and using the simplified viscoelastic continuum damage model with a dissipated pseudoenergy concept (the so-called DR failure criterion). This paper presents DR and Sapp values for 10 different asphalt mixtures commonly used in Georgia. The relationships among DR, Sapp, and mix design factors such as nominal maximum aggregate size (NMAS), asphalt binder type, and binder content were investigated to determine ways that these factors affect DR and Sapp. The Sapp parameter was found to have a strong relationship with the polymer modification and NMAS of the asphalt mixtures. Based on the experimental data and the Georgia Department of Transportation’s practical guidelines for specific mixtures, this study developed Sapp threshold values for different traffic levels. Finally, the experimental data were used to run pavement performance analyses using AASHTOWare Pavement ME Design software and FlexPAVE; the latter uses the S-VECD model for cracking evaluation. Top-down and bottom-up cracking performance was determined from a 10.2 cm (4 in.) thick single-layer pavement and a 15.2 cm (6 in.) thick 2-layer pavement. The results are used to discuss the different ways the two programs evaluate cracking. DA - 2019/11/1/ PY - 2019/11/1/ DO - 10.1061/(ASCE)MT.1943-5533.0002870 VL - 31 IS - 11 SP - SN - 1943-5533 KW - Simplified viscoelastic continuum damage (S-VECD) KW - D-R failure criterion KW - Apparent damage capacity (S-app) KW - FlexPAVE KW - AASHTOWare Pavement ME Design ER - TY - JOUR TI - Electrochemical and Microbiological Characterization of Bioanode Communities Exhibiting Variable Levels of Startup Activity AU - Ortiz-Medina, Juan F. AU - Call, Douglas F. T2 - FRONTIERS IN ENERGY RESEARCH AB - Microbial electrochemical technologies require the establishment of anode biofilms to generate electrical current. The factors driving bioanode formation and their variability during startup remain unclear, leading to a lack of effective strategies to initiate larger-scale systems. Accordingly, our objective was to characterize the electrochemical properties and microbial community structure of a large set of replicate bioanodes during their first cycle of current generation. To do this, we operated eight bioanode replicates at each of two fixed electrode potentials (−0.15 V and +0.15 V vs. standard hydrogen electrode) for one fed-batch cycle. We found that startup time decreased and maximum current generation increased at +0.15 V compared to −0.15 V, but at both potentials the bioanode replicates clustered into three distinct activity levels based on when they initiated current. Despite a large variation in current generation across the eight +0.15 V bioanodes, bioanode resistance and abundance of Geobacter species remained quite similar, differing by only 10% and 12%, respectively. At −0.15 V, current production strongly followed Geobacter species abundance and bioanode resistance, wherein the largest abundance of Geobacter was associated with the lowest charge transfer resistance. Our findings show that startup variability occurs at both applied potentials, but the underlying electrochemical and microbial factors driving variability are dependent on the applied potential. DA - 2019/9/19/ PY - 2019/9/19/ DO - 10.3389/fenrg.2019.00103 VL - 7 SP - SN - 2296-598X KW - microbial electrochemical technologies KW - bioanode KW - Geobacter KW - bioreactor start-up KW - bioenergy ER - TY - JOUR TI - A methodology for the seismic multilevel assessment of unreinforced masonry church inventories in the Groningen area AU - Moratti, Matteo AU - Gaia, Federica AU - Martini, Sara AU - Tsioli, Chrysanthi AU - Grecchi, Giulia AU - Casotto, Chiara AU - Calvi, Gian Michele AU - Den Hertog, Dick AU - Calvi, Paolo Martino AU - Proestos, Giorgio Talotti T2 - BULLETIN OF EARTHQUAKE ENGINEERING DA - 2019/8// PY - 2019/8// DO - 10.1007/s10518-019-00575-7 VL - 17 IS - 8 SP - 4625-4650 SN - 1573-1456 UR - https://doi.org/10.1007/s10518-019-00575-7 KW - Church KW - Inventory prioritization KW - Masonry KW - Multilevel methodology KW - Seismic assessment KW - WebGIS KW - In-plane KW - Out-of-plane ER - TY - JOUR TI - The role of energy storage in deep decarbonization of electricity production (vol 10, 3413, 2019) AU - Arbabzadeh, Maryam AU - Sioshansi, Ramteen AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. T2 - NATURE COMMUNICATIONS AB - An amendment to this paper has been published and can be accessed via a link at the top of the paper. DA - 2019/8/26/ PY - 2019/8/26/ DO - 10.1038/s41467-019-11778-6 VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Retrospective Analysis of Nontuberculous Mycobacterial Infection and Monochloramine Disinfection of Municipal Drinking Water in Michigan AU - Kotlarz, Nadine AU - Raskin, Lutgarde AU - Zimbric, Madsen AU - Errickson, Josh AU - LiPuma, John J. AU - Caverly, Lindsay J. T2 - MSPHERE AB - Infections by nontuberculous mycobacteria (NTM) are primarily acquired from environmental sources, including exposure to municipally treated drinking water. Higher levels of NTM have been reported in drinking water disinfected with monochloramine than in that disinfected with chlorine. However, the relationships between water treatment practices and NTM infection are unclear. The objective of this study was to examine a possible relationship between residual disinfectant used for municipal drinking water treatment (monochloramine or chlorine) and NTM infection. We retrospectively reviewed NTM diagnostic tests performed at a single health care center during a 15-year period. Information on municipal water treatment practices, including disinfectant and primary source water type, was obtained for 140 cities. Based on a logistic regression model, municipal drinking water disinfection with monochloramine compared to chlorine was not associated with NTM infection (P = 0.24). An additional model variable examining water source showed that the likelihood of having an NTM infection was 1.46 times higher for patients residing in cities with drinking water derived from surface water than for those residing in cities with drinking water derived from groundwater (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.03 to 2.08; P = 0.04). In an inverse propensity score weighted regression, monochloramine disinfection was also not associated with NTM infection. A moderate effect on NTM infection rates was observed in the weighted regression for municipal drinking water derived from surface water, though the results were not statistically significant (OR, 1.24; 95% CI, 0.92 to 1.69; P = 0.17).IMPORTANCE Infections by nontuberculous mycobacteria (NTM) result in significant morbidity, mortality, and health care costs. NTM are primarily acquired from environmental sources, including exposure to municipally treated drinking water. Higher levels of NTM have been reported in drinking water disinfected with monochloramine than in drinking water disinfected with chlorine. Our results suggest that municipal drinking water disinfection with monochloramine compared to chlorine is not associated with higher risk of NTM infection. This is important given that regulations that limit drinking water concentrations of disinfection by-products, which are formed primarily when chlorine disinfection is used, incentivize drinking water utilities to change from chlorine disinfection to monochloramine disinfection. DA - 2019/// PY - 2019/// DO - 10.1128/mSphere.00160-19 VL - 4 IS - 4 SP - SN - 2379-5042 UR - https://doi.org/10.1128/mSphere.00160-19 KW - disinfection KW - drinking water KW - infection KW - monochloramine KW - nontuberculous mycobacteria ER - TY - JOUR TI - Approaches to fill data gaps and evaluate process completeness in LCA—perspectives from solid waste management systems AU - Henriksen, Trine AU - Levis, James W. AU - Barlaz, Morton A. AU - Damgaard, Anders T2 - The International Journal of Life Cycle Assessment AB - Large data amounts are required in an LCA, but often, site-specific data are missing and less representative surrogate data must be used to fill data gaps. No standardized rules exist on how to address data gaps and process completeness. We suggest a systematic evaluation of process completeness, identification of data gaps, and application of surrogate values to fill the gaps. The study focus on foreground process data. A solid waste management (SWM) scenario was used to illustrate the suggested method. The expected input and output flows in a waste incineration model were identified based on legislation and expert judgment, after which process completeness scores were calculated and missing flows identified. To illustrate the use of different types of surrogate data to fill data gaps, data gaps were selected for 16 different parameters in five SWM processes. We compared the global warming potential (GWP) from using surrogate data, and from leaving the gap, to identify the data gaps where representative surrogate data should be used. The completeness score for the material inputs to waste incineration was 78%, and the missing flows were auxiliary fuels and precipitation chemicals. The completeness score for air emissions were between 38 and 50% with and without expert judgment. If only greenhouse gases were considered (CO2, CH4, and N2O), the completeness score would be 67%. Applying weighting factors according to the greenhouse gas contribution in the USA gave a completeness score of 94%. The system-wide data gaps, where representative surrogate data should be applied, were the CH4 release from composting; electricity generation efficiency of incineration; recovery efficiencies at a material recovery facility; and composition of the plastic, metal, and paper fractions in the household waste; in these cases, leaving the gap changed the GWP results by > 5%. Completeness evaluation should take into account the relevance and importance of flows; relevance depends on the considered life cycle impact methods and importance depends on the weighting of the different flows. The set of expected flows and evaluation of relevance and importance must be documented in a transparent manner. The choice of surrogate values to fill data gaps depends on the availability of secondary data and on whether the data gap matters, i.e., significantly affects the LCA results. The suggested method can be used to properly document the identification of missing flows and to select and apply surrogate values to fill the data gaps. DA - 2019/2/26/ PY - 2019/2/26/ DO - 10.1007/s11367-019-01592-z VL - 24 IS - 9 SP - 1587-1601 J2 - Int J Life Cycle Assess LA - en OP - SN - 0948-3349 1614-7502 UR - http://dx.doi.org/10.1007/s11367-019-01592-z DB - Crossref KW - Completeness KW - Data gaps KW - Surrogate values KW - Representativeness KW - Waste management KW - LCA ER - TY - JOUR TI - Development of a pseudo strain energy-based fatigue failure criterion for asphalt mixtures AU - Wang, Yizhuang AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - This paper presents a new energy-based failure criterion that is based on the simplified viscoelastic continuum damage model. This study found that the average reduction in pseudo stiffness up to failure, referred to here as D R , is a material constant that is independent of mode of loading, temperature, and stress/strain amplitude. Twenty different asphalt mixtures were used to validate the proposed method. This paper presents typical values of D R and shows that the D R changes with the mixture characteristics. The advantages of the D R failure criterion over a previous failure criterion (known as the G R criterion) are that it: (1) allows the prediction of fatigue failure in arithmetic scale, which reduces possible errors due to extrapolation of the accelerated laboratory fatigue test data to realistic traffic volumes encountered in the field and (2) reduces the number of tests required to characterise the failure criterion. Statistical analysis was performed in this study and the results show confidence levels that can be obtained from two or three fatigue tests. DA - 2019/10/3/ PY - 2019/10/3/ DO - 10.1080/10298436.2017.1394100 VL - 20 IS - 10 SP - 1182-1192 SN - 1477-268X KW - Asphalt mixtures KW - fatigue KW - failure criterion KW - S-VECD model KW - dissipated pseudo strain energy ER - TY - JOUR TI - Dynamic Modeling of Microalgae Growth and Lipid Production under Transient Light and Nitrogen Conditions AU - Wang, Diyuan AU - Lai, Yi-Chun AU - Karam, Amanda L. AU - de los Reyes, Francis L., III AU - Ducoste, Joel J. T2 - Environmental Science & Technology AB - We developed a new dynamic model to characterize how light and nitrogen regulate the cellular processes of photosynthetic microalgae leading to transient changes in the production of neutral lipids, carbohydrates, and biomass. Our model recapitulated the versatile neutral lipid synthesis pathways via (i) carbon reuse from carbohydrate metabolism under nitrogen sufficiency and (ii) fixed carbon redirection under nitrogen depletion. We also characterized the effects of light adaptation, light inhibition hysteresis, and nitrogen limitation on photosynthetic carbon fixation. The formulated model was calibrated and validated with experimental data of Dunaliella viridis cultivated in a lab-scale photobioreactor (PBR) under various light (low/moderate/high) and nitrogen (sufficient/limited) conditions. We conducted the identifiability, uncertainty, and sensitivity analyses to verify the model reliability using the profile likelihood method, the Markov chain Monte Carlo (MCMC) technique, and the extended Fourier Amplitude Sensitivity Test (eFAST). Our model predictions agreed well with experimental observations and suggested potential model improvement by incorporating a lipid degradation mechanism. The insights from our model-driven analysis helped improve the mechanistic understanding of transient algae growth and bioproducts formation under environmental variations and could be applied to optimize biofuel and biomass production. DA - 2019/8/26/ PY - 2019/8/26/ DO - 10.1021/acs.est.9b02908 VL - 53 IS - 19 SP - 11560-11568 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.9b02908 DB - Crossref ER - TY - JOUR TI - Out-of-plane buckling instability limit state for boundary regions of special RC structural walls AU - Haro, A. G. AU - Kowalsky, M. AU - Chai, Y. H. T2 - Bulletin of Earthquake Engineering DA - 2019/6/15/ PY - 2019/6/15/ DO - 10.1007/s10518-019-00667-4 VL - 17 IS - 9 SP - 5159-5182 J2 - Bull Earthquake Eng LA - en OP - SN - 1570-761X 1573-1456 UR - http://dx.doi.org/10.1007/s10518-019-00667-4 DB - Crossref KW - RC structural walls KW - Boundary elements KW - Out-of-plane buckling KW - Experimental tests ER - TY - JOUR TI - Enhancement of Coal Ash Compressibility Parameters Using Microbial-Induced Carbonate Precipitation AU - Montoya, Brina M. AU - Safavizadeh, Shahin AU - Gabr, Mohammed A. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING DA - 2019/5// PY - 2019/5// DO - 10.1061/(ASCE)GT.19435606.0002036 VL - 145 IS - 5 SP - SN - 1943-5606 ER - TY - JOUR TI - Predictive multi-hazard hurricane data-based fragility model for residential homes AU - Massarra, Carol C. AU - Friedland, Carol J. AU - Marx, Brian D. AU - Dietrich, J. Casey T2 - Coastal Engineering AB - Multi-hazard hurricane data-based fragility models are able to represent multiple predictor variables, be validated based on observed data, and consider variability in building characteristics and hazard variables. This paper develops predictive hurricane, multi-hazard, single-family building fragility models for ordered categorical damage states (DS) and binary complete failure/non-complete failure using proportional odds cumulative logit and logistic regression models, respectively. In addition to their simplicity, these models are able to represent multiple hurricane hazard variables and include variable interactions, thus improving model fitting and damage prediction. Surveys of physical damage in coastal Mississippi following Hurricane Katrina (2005) and high-resolution numerical hindcast hazard intensities from the Simulating WAves Nearshore and ADvanced CIRCulation (SWAN + ADCIRC) models are used as model input. Prediction accuracy is expressed in terms of cross-validation (CV) and evaluated using leave-one-out cross-validation (LOOCV). Thirty-nine combinations of global damage response variables were investigated. Of these models, six DS and one complete failure model met the evaluation criteria. Maximum significant wave height was the only significant hazard variable for the DS models, while maximum 3-s gust wind speed, maximum surge depth, and maximum water speed were found to be significant predictors for the complete failure model. Model prediction external accuracy ranged from 81% to 87%. DA - 2019/9// PY - 2019/9// DO - 10.1016/j.coastaleng.2019.04.008 VL - 151 SP - 10-21 J2 - Coastal Engineering LA - en OP - SN - 0378-3839 UR - http://dx.doi.org/10.1016/j.coastaleng.2019.04.008 DB - Crossref KW - Predictive fragility models KW - Data-based statistical models KW - Residential buildings KW - Hurricane hazards ER - TY - JOUR TI - Relating nitrogen concentration and light intensity to the growth and lipid accumulation of Dunaliella viridis in a photobioreactor AU - Lai, Yi-Chun AU - Karam, Amanda L. AU - Sederoff, Heike W. AU - Ducoste, Joel J. AU - de los Reyes, Francis L. T2 - Journal of Applied Phycology DA - 2019/8/28/ PY - 2019/8/28/ DO - 10.1007/s10811-019-01897-4 VL - 31 IS - 6 SP - 3397-3409 J2 - J Appl Phycol LA - en OP - SN - 0921-8971 1573-5176 UR - http://dx.doi.org/10.1007/s10811-019-01897-4 DB - Crossref KW - Dunaliella viridis KW - Chlorophyta KW - Lipid KW - Light KW - Nitrogen KW - Photobioreactor ER - TY - JOUR TI - Optimal network-level traffic signal control: A benders decomposition-based solution algorithm AU - Mohebifard, Rasool AU - Hajbabaie, Ali T2 - Transportation Research Part B: Methodological AB - This paper formulates the network-level traffic signal timing optimization problem as a Mixed-Integer Non-Linear Program (MINLP) and presents a customized methodology to solve it with a tight optimality gap. The MINLP is based on the Cell Transmission Model (CTM) network loading concept and captures the fundamental flow-density diagram of the CTM explicitly by considering closed-form constraints in the model and thus, eliminates the flow holding-back problem. The proposed solution algorithm is based on the Benders decomposition technique and decomposes the original MINLP to an equivalent Integer Program (IP) (Master problem), and a new MINLP (Primal problem). We will show that the new MINLP has only one optimal non-holding-back solution that can be found by a CTM simulation run. We will prove that the proposed solution technique guarantees convergence to optimal solutions with a finite number of iterations. Furthermore, we propose a dual estimation algorithm for the new MINLP (the Primal problem), which utilizes a simulation-based approach to generate Benders cuts instead of solving a complex optimization program. We applied the proposed solution technique to a simulated network of 20 intersections under various demand patterns and observed an optimality gap of at most 2% under all tested conditions. We compared the solutions of the proposed algorithm with two benchmark algorithms and found reductions in total travel time ranging from 7.0% to 35.7%. DA - 2019/// PY - 2019/// DO - 10.1016/j.trb.2019.01.012 VL - 121 SP - 252-274 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85061027902&partnerID=MN8TOARS KW - Traffic signal control KW - Cell transmission model KW - Benders decomposition KW - Flow holding-back problem ER - TY - JOUR TI - Distributed Optimization and Coordination Algorithms for Dynamic Traffic Metering in Urban Street Networks AU - Mohebifard, R. AU - Hajbabaie, A. T2 - IEEE Transactions on Intelligent Transportation Systems AB - Previous research has shown that proper metering of entry traffic to urban street networks, similar to metering traffic on on-ramps in freeway facilities, reduces traffic congestion, especially in oversaturated flow conditions. Building on the previous research, this paper presents a real-time and scalable methodology for finding near-optimal metering rates dynamically in urban street networks. The problem is formulated into a mixed-integer linear program (MILP) based on the cell transmission model. We propose a distributed optimization scheme that decomposes the network level MILP into several link-level MILPs to reduce the complexity of the problem. We convert the link-level MILPs to linear programs to reduce the computational complexity further. Moreover, we create distributed coordination between the link-level linear programs to push the solutions toward optimality. The distributed optimization and coordination solution algorithm is incorporated into a rolling horizon technique to account for the time-varying demand and capacity and to reduce the computational complexity further. We applied the proposed solution technique to a number of case studies and observed that it was scalable and real time and found solutions that were at most 2.2% different from the optimal solution of the problem. Like the previous studies, we found significant improvements in network operations as a result of traffic metering. DA - 2019/// PY - 2019/// DO - 10.1109/TITS.2018.2848246 VL - 20 IS - 5 SP - 1930-1941 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85050987048&partnerID=MN8TOARS KW - Dynamic traffic metering KW - perimeter control KW - distributed optimization KW - distributed coordination KW - model predictive control KW - mixed-integer linear program ER - TY - JOUR TI - A decomposition scheme for parallelization of system optimal dynamic traffic assignment on urban networks with multiple origins and destinations AU - Mehrabipour, Mehrzad AU - Hajibabai, Leila AU - Hajbabaie, Ali T2 - Computer-Aided Civil and Infrastructure Engineering AB - Abstract This paper presents a decomposition scheme to find near‐optimal solutions to a cell transmission model‐based system optimal dynamic traffic assignment problem with multiple origin‐destination pairs. A linear and convex formulation is used to define the problem characteristics. The decomposition is designed based on the Dantzig–Wolfe technique that splits the set of decision variables into subsets through the construction of a master problem and subproblems. Each subproblem includes only a single origin‐destination pair with significantly less computational burden compared to the original problem. The master problem represents the coordination between subproblems through the design of interactive flows between the pairs. The proposed methodology is implemented in two case study networks of 20 and 40 intersections with up to 25 origin‐destination pairs. The numerical results show that the decomposition scheme converges to the optimal solution, within 2.0% gap, in substantially less time compared to a benchmark solution, which confirms the computational efficiency of the proposed algorithm. Various network performance measures have been assessed based on different traffic state scenarios to draw managerial insights. DA - 2019/// PY - 2019/// DO - 10.1111/mice.12455 VL - 34 IS - 10 SP - 915-931 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85066156002&partnerID=MN8TOARS ER - TY - JOUR TI - A consensus-based distributed trajectory control in a signal-free intersection AU - Mirheli, Amir AU - Tajalli, Mehrdad AU - Hajibabai, Leila AU - Hajbabaie, Ali T2 - Transportation research part C: emerging technologies AB - This paper develops a distributed cooperative control logic to determine conflict-free trajectories for connected and automated vehicles (CAVs) in signal-free intersections. The cooperative trajectory planning problem is formulated as vehicle-level mixed-integer non-linear programs (MINLPs) that aim to minimize travel time of each vehicle and their speed variations, while avoiding near-crash conditions. To push vehicle-level solutions towards global optimality, we develop a coordination scheme between CAVs on conflicting movements. The coordination scheme shares vehicle states (i.e., location) over a prediction horizon and incorporates such information in CAVs’ respective MINLPs. Therefore, the CAVs will reach consensus through an iterative process and select conflict-free trajectories that minimize their travel time. The numerical experiments quantify the effects of the proposed methodology on traffic safety and performance measures in an intersection. The results show that the proposed distributed coordinated framework converges to near-optimal CAV trajectories with no conflicts in the intersection neighborhood. While the solutions are found in real-time, the comparison to a central intersection control logic for CAVs indicates a maximum marginal objective value of 2.30%. Furthermore, the maximum marginal travel time, throughput, and average speed do not exceed 0.5%, 0.1%, and 0.5%, respectively. The proposed control logic reduced travel time by 43.0–70.5%, and increased throughput and average speed respectively by 0.8–115.6% and 59.1–400.0% compared to an optimized actuated signal control, while eliminating all near-crash conditions. DA - 2019/// PY - 2019/// DO - 10.1016/j.trc.2019.01.004 VL - 100 SP - 161-176 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060455583&partnerID=MN8TOARS KW - Distributed algorithm KW - Coordination KW - Signal-free KW - Cooperative KW - Control logic KW - Connected and autonomous vehicles ER - TY - JOUR TI - African American Exposure to Prescribed Fire Smoke in Georgia, USA AU - Johnson Gaither, Cassandra AU - Afrin, Sadia AU - Garcia-Menendez, Fernando AU - Odman, M. Talat AU - Huang, Ran AU - Goodrick, Scott AU - Ricardo da Silva, Alan T2 - International Journal of Environmental Research and Public Health AB - Our project examines the association between percent African American and smoke pollution in the form of prescribed burn-sourced, fine particulate matter (PM2.5) in the U.S. state of Georgia for 2018. (1) Background: African Americans constitute 32.4% of Georgia’s population, making it the largest racial/ethnic minority group in the state followed by Hispanic Americans at 9.8%. African Americans, Hispanic Americans, and lower wealth groups are more likely than most middle and upper income White Americans to be exposed to environmental pollutants. This is true because racial and ethnic minorities are more likely to live in urban areas where pollution is more concentrated. As a point of departure, we examine PM2.5 concentrations specific to prescribed fire smoke, which typically emanates from fires occurring in rural or peri-urban areas. Two objectives are specified: a) examine the association between percent African American and PM2.5 concentrations at the census tract level for Georgia, and b) identify emitters of PM2.5 concentrations that exceed National Ambient Air Quality Standards (NAAQS) for the 24-h average, i. e., >35 µg/m3. (2) Methods: For the first objective, we estimate a spatial Durbin error model (SDEM) where pollution concentration (PM2.5) estimates for 1683 census tracts are regressed on percent of the human population that is African American or Hispanic; lives in mobile homes; and is employed in agriculture and related occupations. Also included as controls are percent evergreen forest, percent mixed evergreen/deciduous forest, and variables denoting lagged explanatory and error variables, respectively. For the second objective, we merge parcel and prescribed burn permit data to identify landowners who conduct prescribed fires that produce smoke exceeding the NAAQS. (3) Results: Percent African American and mobile home dweller are positively related to PM2.5 concentrations; and government and non-industrial private landowners are the greatest contributors to exceedance levels (4) Conclusions: Reasons for higher PM2.5 concentrations in areas with higher African American and mobile home percent are not clear, although we suspect that neither group is a primary contributor to prescribed burn smoke but rather tend to live proximate to entities, both public and private, that are. Also, non-industrial private landowners who generated prescribed burn smoke exceeding NAAQS are wealthier than others, which suggests that African American and other environmental justice populations are less likely to contribute to exceedance levels in the state. DA - 2019/8/24/ PY - 2019/8/24/ DO - 10.3390/ijerph16173079 VL - 16 IS - 17 SP - 3079 J2 - IJERPH LA - en OP - SN - 1660-4601 UR - http://dx.doi.org/10.3390/ijerph16173079 DB - Crossref KW - prescribed fire KW - environmental justice KW - socially vulnerable populations KW - Georgia ER - TY - JOUR TI - Global diversity and biogeography of bacterial communities in wastewater treatment plants AU - Wu, Linwei AU - Ning, Daliang AU - Zhang, Bing AU - Li, Yong AU - Zhang, Ping AU - Shan, Xiaoyu AU - Zhang, Qiuting AU - Brown, Mathew AU - Li, Zhenxin AU - Van Nostrand, Joy D. AU - Ling, Fangqiong AU - Xiao, Naijia AU - Zhang, Ya AU - Vierheilig, Julia AU - Wells, George F. AU - Yang, Yunfeng AU - Deng, Ye AU - Tu, Qichao AU - Wang, Aijie AU - Zhang, Tong AU - He, Zhili AU - Keller, Jurg AU - Nielsen, Per H. AU - Alvarez, Pedro J. J. AU - Criddle, Craig S. AU - Wagner, Michael AU - Tiedje, James M. AU - He, Qiang AU - Curtis, Thomas P. AU - Stahl, David A. AU - Alvarez-Cohen, Lisa AU - Rittmann, Bruce E. AU - Wen, Xianghua AU - Zhou, Jizhong AU - Acevedo, Dany AU - Agullo-Barcelo, Miriam AU - Andersen, Gary L. AU - Araujo, Juliana Calabria AU - Boehnke, Kevin AU - Bond, Philip AU - Bott, Charles B. AU - Bovio, Patricia AU - Brewster, Rebecca K. AU - Bux, Faizal AU - Cabezas, Angela AU - Cabrol, Lea AU - Chen, Si AU - Etchebehere, Claudia AU - Ford, Amanda AU - Frigon, Dominic AU - Sanabria Gomez, Janeth AU - Griffin, James S. AU - Gu, April Z. AU - Habagil, Moshe AU - Hale, Lauren AU - Hardeman, Steven D. AU - Harmon, Marc AU - Horn, Harald AU - Hu, Zhiqiang AU - Jauffur, Shameem AU - Johnson, David R. AU - Keucken, Alexander AU - Kumari, Sheena AU - Leal, Cintia Dutra AU - Lebrun, Laura A. AU - Lee, Jangho AU - Lee, Minjoo AU - Lee, Zarraz M. P. AU - Li, Mengyan AU - Li, Xu AU - Liu, Yu AU - Luthy, Richard G. AU - Mendonca-Hagler, Leda C. AU - Menezes, Francisca Gleire AU - Meyers, Arthur J. AU - Mohebbi, Amin AU - Oehmen, Adrian AU - Palmer, Andrew AU - Parameswaran, Prathap AU - Park, Joonhong AU - Patsch, Deborah AU - Reginatto, Valeria AU - Reyes, Francis L., III AU - Noyola Robles, Adalberto AU - Rossetti, Simona AU - Sidhu, Jatinder AU - Sloan, William T. AU - Smith, Kylie AU - Sousa, Oscarina Viana AU - Stephens, Kyle AU - Tian, Renmao AU - Tooker, Nicholas B. AU - Cobos Vasconcelos, Daniel AU - Wakelin, Steve AU - Wang, Bei AU - Weaver, Joseph E. AU - West, Stephanie AU - Wilmes, Paul AU - Woo, Sung-Geun AU - Wu, Jer-Horng AU - Wu, Liyou AU - Xi, Chuanwu AU - Xu, Meiying AU - Yan, Tao AU - Yang, Min AU - Young, Michelle AU - Yue, Haowei AU - Zhang, Qian AU - Zhang, Wen AU - Zhang, Yu AU - Zhou, Hongde AU - Brown, Matthew T2 - Nature Microbiology AB - Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, the diversity of microorganisms and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analysed the 16S ribosomal RNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small, global core bacterial community (n = 28 operational taxonomic units) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal and drift), although deterministic factors (temperature and organic input) are also important. Our findings enhance our mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes. DA - 2019/5/13/ PY - 2019/5/13/ DO - 10.1038/s41564-019-0426-5 VL - 4 IS - 7 SP - 1183-1195 J2 - Nat Microbiol LA - en OP - SN - 2058-5276 UR - http://dx.doi.org/10.1038/s41564-019-0426-5 DB - Crossref ER - TY - JOUR TI - Modeling of wave energy converters by GPUSPH and Project Chrono AU - Wei, Zhangping AU - Edge, Billy L. AU - Dalrymple, Robert A. AU - Herault, Alexis T2 - OCEAN ENGINEERING AB - This study presents a fully coupled numerical approach to study wave energy converters interaction with water waves. The open-source Smoothed Particle Hydrodynamics model GPUSPH is used to resolve wave dynamics and compute the hydrodynamic force on wave energy converters. The dynamics of wave energy converter is computed by the open-source physics engine, Project Chrono. The capability of the coupled numerical model to handle wave-body interaction is validated by considering a floating body in still water. The results show that the coupled model correctly predicts the balance between the floating body weight and the buoyancy force. Furthermore, the effectiveness of density diffusion method in reducing acoustic noise in a weakly compressible SPH model is also justified. In addition, the model is validated by laboratory experiment on floating body interaction with nonlinear wave packet. The model is then applied to simulate two types of wave energy converters. We conduct a thorough study of GPUSPH modeling of surface-piercing oscillating wave surge converter under waves. GPUSPH accurately predicts both wave gauge measurements and the device rotation as recorded in the laboratory. By virtue of the Project Chrono library we examine the power take-off scenario of the oscillating wave surge converter by introducing kinematic constraint into the system. The device performance under storm condition is further examined. We further present and simulate a conceptualized catenary mooring wave energy converter device, CSI-Device, under real sea states. We not only examine the interaction of CSI-Device with waves, but also we obtain the mooring force on the device that can facilitate the design of wave energy converters. We show that to maximize the energy extraction, it is important to design the device to have a natural frequency similar to the wave period of deployment site to maximize the swing motion of the pendulum. Finally the interaction of CSI-Device under different sea states with both relatively small and large wave heights are evaluated by placing the device in a directional spectral wave basin. Overall, this study shows that the open-source model GPUSPH is an efficient tool for modeling wave energy conversion devices in directional nonlinear sea states. DA - 2019/7/1/ PY - 2019/7/1/ DO - 10.1016/j.oceaneng.2019.04.029 VL - 183 SP - 332-349 SN - 0029-8018 KW - Wave energy converter KW - Floating body KW - Power take-off KW - Wave-body interaction KW - GPUSPH KW - Project chrono ER - TY - JOUR TI - Impact of Crack Sealant on Pavement Skid Resistance AU - Fried, Andrew AU - Malladi, Haritha AU - Castorena, Cassie T2 - TRANSPORTATION RESEARCH RECORD AB - Crack sealing is often a cost-effective preventive maintenance strategy for prolonging pavement service life when applied to pavements in relatively good condition. Crack sealing is generally ineffective for extending the life of heavily cracked pavements. However, crack sealing is often applied to pavements with extensive cracking. The application of crack sealing to pavements with extensive cracking can pose a skid resistance hazard. This study investigates the relationship between the amount and distribution of crack sealant application and pavement skid resistance. Locked-Wheel Skid Tester (LWST) testing was conducted on several pavement projects in North Carolina, United States, with varying amounts and patterns of crack sealant. Images of the locations of LWST testing were obtained and processed to determine the percentage of the pavement surface area covered by crack sealant. A relationship between the percentage of the wheel path covered by crack sealant and LWST results was established that demonstrates the application of high amounts of crack sealant to the wheel path can pose safety hazards. The effect of crack sealant on pavement skid resistance is a function of the existing pavement’s frictional characteristics. The results of this study highlight the need for the development of crack sealant specification provisions to avoid the loss of skid resistance. DA - 2019/7// PY - 2019/7// DO - 10.1177/0361198119849590 VL - 2673 IS - 7 SP - 362-370 SN - 2169-4052 ER - TY - JOUR TI - Relationship between Asphalt Binder Parameters and Asphalt Mixture Rutting AU - Salim, Ramadan AU - Gundla, Akshay AU - Zalghout, Ali AU - Underwood, B. Shane AU - Kaloush, Kamil E. T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The selection and specification of asphalt binder is one of the factors that ultimately affect the long-term performance of asphalt pavements. Many agencies currently follow AASHTO M320 for their binder specifications, where the ratio of dynamic modulus to the sine of the phase angle, | G*|/sin δ, is the binder rutting parameter. However, an alternative now exists, AASHTO M332, which uses the non-recovered creep compliance, J nr , for this purpose. In this paper, the relative merits of these two parameters are compared using experimental results from 21 different asphalt mixtures from Arizona. The rutting parameters according to AASHTO M332 and M320 were determined for each of the binders in these mixtures and, for each mixture, two rutting performance tests were conducted: Hamburg wheel tracking test and repeated load permanent deformation test. The two binder rutting parameters demonstrated very high correlation to one another for non-polymer modified asphalts, but inconsistent correlation for polymer modified asphalts. Both Hamburg wheel tracking tests and repeated load permanent deformation tests showed positive correlations to both | G*|/sin δ and J nr . It was concluded that, while both parameters showed good correlation, the J nr of the binder relates better to mixture rutting than does | G*|/sin δ. Considering the results in this study, it is believed that J nr is a slightly better rutting parameter for binder specifications. DA - 2019/6// PY - 2019/6// DO - 10.1177/0361198119842129 VL - 2673 IS - 6 SP - 431-446 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198119842129 DB - Crossref ER - TY - JOUR TI - Development of a Performance-Volumetric Relationship for Asphalt Mixtures AU - Wang, Yizhuang David AU - Ghanbari, Amir AU - Underwood, Benjamin Shane AU - Kim, Youngsoo Richard T2 - Transportation Research Record: Journal of the Transportation Research Board AB - This paper aims to establish the relationship between the volumetric performance of asphalt mixtures and their performance in relation to pavement fatigue cracking and rutting. A good performance-volumetric relationship (PVR) can dramatically improve the working efficiency of mixtures and can be used in future performance-engineered mixture design and performance-related specifications. For this study, three asphalt mixtures were first designed to incorporate systematic changes in volumetric conditions, then fatigue cracking and rutting performance tests were conducted at each condition. Statistical analyses of the results suggest that a first-order (linear) model and power model would be an appropriate form of the PVR function. The number of volumetric conditions required to calibrate the PVR function is also investigated. Finally, a rule of thumb for selecting the volumetric conditions for the model calibrations is provided. The verification results show that the proposed PVR function is able to capture the response of mixture performance to changes in volumetric conditions. DA - 2019/5/9/ PY - 2019/5/9/ DO - 10.1177/0361198119845364 VL - 2673 IS - 6 SP - 416-430 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198119845364 DB - Crossref ER - TY - JOUR TI - Are e-scooters polluters? The environmental impacts of shared dockless electric scooters AU - Hollingsworth, Joseph AU - Copeland, Brenna AU - Johnson, Jeremiah X. T2 - ENVIRONMENTAL RESEARCH LETTERS AB - Abstract Shared stand-up electric scooters are now offered in many cities as an option for short-term rental, and marketed for short-distance travel. Using life cycle assessment, we quantify the total environmental impacts of this mobility option associated with global warming, acidification, eutrophication, and respiratory impacts. We find that environmental burdens associated with charging the e-scooter are small relative to materials and manufacturing burdens of the e-scooters and the impacts associated with transporting the scooters to overnight charging stations. The results of a Monte Carlo analysis show an average value of life cycle global warming impacts of 202 g CO 2 -eq/passenger-mile, driven by materials and manufacturing (50%), followed by daily collection for charging (43% of impact). We illustrate the potential to reduce life cycle global warming impacts through improved scooter collection and charging approaches, including the use of fuel-efficient vehicles for collection (yielding 177 g CO 2 -eq/passenger-mile), limiting scooter collection to those with a low battery state of charge (164 g CO 2 -eq/passenger-mile), and reducing the driving distance per scooter for e-scooter collection and distribution (147 g CO 2 -eq/passenger-mile). The results prove to be highly sensitive to e-scooter lifetime; ensuring that the shared e-scooters are used for two years decreases the average life cycle emissions to 141 g CO 2 -eq/passenger-mile. Under our Base Case assumptions, we find that the life cycle greenhouse gas emissions associated with e-scooter use is higher in 65% of our Monte Carlo simulations than the suite of modes of transportation that are displaced. This likelihood drops to 35%–50% under our improved and efficient e-scooter collection processes and only 4% when we assume two-year e-scooter lifetimes. When e-scooter usage replaces average personal automobile travel, we nearly universally realize a net reduction in environmental impacts. DA - 2019/8// PY - 2019/8// DO - 10.1088/1748-9326/ab2da8 VL - 14 IS - 8 SP - SN - 1748-9326 KW - electric scooter KW - life cycle assessment KW - transportation KW - environmental impacts ER - TY - JOUR TI - The role of energy storage in deep decarbonization of electricity production AU - Arbabzadeh, Maryam AU - Sioshansi, Ramteen AU - Johnson, Jeremiah X. AU - Keoleian, Gregory A. T2 - NATURE COMMUNICATIONS AB - Abstract Deep decarbonization of electricity production is a societal challenge that can be achieved with high penetrations of variable renewable energy. We investigate the potential of energy storage technologies to reduce renewable curtailment and CO 2 emissions in California and Texas under varying emissions taxes. We show that without energy storage, adding 60 GW of renewables to California achieves 72% CO 2 reductions (relative to a zero-renewables case) with close to one third of renewables being curtailed. Some energy storage technologies, on the other hand, allow 90% CO 2 reductions from the same renewable penetrations with as little as 9% renewable curtailment. In Texas, the same renewable-deployment level leads to 54% emissions reductions with close to 3% renewable curtailment. Energy storage can allow 57% emissions reductions with as little as 0.3% renewable curtailment. We also find that generator flexibility can reduce curtailment and the amount of energy storage that is needed for renewable integration. DA - 2019/7/30/ PY - 2019/7/30/ DO - 10.1038/s41467-019-11161-5 VL - 10 SP - SN - 2041-1723 ER - TY - JOUR TI - Repurposing an energy system optimization model for seasonal power generation planning AU - de Queiroz, A.R. AU - Mulcahy, D. AU - Sankarasubramanian, A. AU - Deane, J.P. AU - Mahinthakumar, G. AU - Lu, N. AU - DeCarolis, J.F. T2 - Energy AB - Seasonal climate variations affect electricity demand, which in turn affects month-to-month electricity planning and operations. Electricity system planning at the monthly timescale can be improved by adapting climate forecasts to estimate electricity demand and utilizing energy models to estimate monthly electricity generation and associated operational costs. The objective of this paper is to develop and test a computationally efficient model that can support seasonal planning while preserving key aspects of system operation over hourly and daily timeframes. To do so, an energy system optimization model is repurposed for seasonal planning using features drawn from a unit commitment model. Different scenarios utilizing a well-known test system are used to evaluate the errors associated with both the repurposed energy system model and an imperfect load forecast. The results show that the energy system optimization model using an imperfect load forecast produces differences in monthly cost and generation levels that are less than 2% compared with a unit commitment model using a perfect load forecast. The enhanced energy system optimization model can be solved approximately 100 times faster than the unit commitment model, making it a suitable tool for future work aimed at evaluating seasonal electricity generation and demand under uncertainty. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.energy.2019.05.126 VL - 181 SP - 1321-1330 J2 - Energy LA - en OP - SN - 0360-5442 UR - http://dx.doi.org/10.1016/j.energy.2019.05.126 DB - Crossref KW - Power generation planning KW - Unit commitment KW - Energy system optimization KW - Seasonal demand forecasts KW - Mathematical programming ER - TY - JOUR TI - Recent increase in catastrophic tropical cyclone flooding in coastal North Carolina, USA: Long-term observations suggest a regime shift AU - Paerl, Hans W. AU - Hall, Nathan S. AU - Hounshell, Alexandria G. AU - Luettich, Richard A., Jr. AU - Rossignol, Karen L. AU - Osburn, Christopher L. AU - Bales, Jerad T2 - SCIENTIFIC REPORTS AB - Abstract Coastal North Carolina, USA, has experienced three extreme tropical cyclone-driven flood events since 1999, causing catastrophic human impacts from flooding and leading to major alterations of water quality, biogeochemistry, and ecological conditions. The apparent increased frequency and magnitudes of such events led us to question whether this is just coincidence or whether we are witnessing a regime shift in tropical cyclone flooding and associated ecosystem impacts. Examination of continuous rainfall records for coastal NC since 1898 reveals a period of unprecedentedly high precipitation since the late-1990’s, and a trend toward increasingly high precipitation associated with tropical cyclones over the last 120 years. We posit that this trend, which is consistent with observations elsewhere, represents a recent regime shift with major ramifications for hydrology, carbon and nutrient cycling, water and habitat quality and resourcefulness of Mid-Atlantic and possibly other USA coastal regions. DA - 2019/7/23/ PY - 2019/7/23/ DO - 10.1038/s41598-019-46928-9 VL - 9 SP - SN - 2045-2322 ER - TY - JOUR TI - Construction quality acceptance performance-related specifications for chip seals AU - Adams, Javon AU - Castorena, Cassie AU - Kim, Y. Richard T2 - JOURNAL OF TRAFFIC AND TRANSPORTATION ENGINEERING-ENGLISH EDITION AB - The research described herein details the establishment of a framework for construction quality acceptance performance-related specifications (PRS) for chip seal surface treatments. This paper establishes acceptance quality characteristics (AQCs) and relationships between the AQCs and related chip seal performance measures. This work is a critical step in developing PRS for constructed chip seal treatments and establishing suitable guidelines for the PRS. The main objective of this paper is to determine appropriate test methods to evaluate each defined AQC. The relationships that are established between the AQCs and chip seal performance are used to define performance ranges and threshold values for a particular performance measure. These performance ranges and threshold values then can be used to define pay factors for the constructed chip seal section. The threshold values and pay factors for each AQC described herein are preliminary recommendations and require further validation prior to implementation. However, this research demonstrates how these PRS would be utilized to ensure acceptable chip seal construction quality in the field. The developed construction quality acceptance PRS framework uses the percent within limits (PWL) concept to determine whether a chip seal lot passes the PRS threshold values and whether the contractor receives full pay, is subject to a pay penalty, or fails the construction PRS and must correct the chip seal within the first year in service, which constitutes the typical warranty period for contracted chip seal work. Finally, recommendations are made as to the next steps in the development and validation of these construction quality acceptance PRS that are needed for implementation by contractors and state roadway maintenance agencies. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.jtte.2019.05.003 VL - 6 IS - 4 SP - 337-348 SN - 2095-7564 KW - Performance-related specifications (PRS) KW - Chip seal KW - Construction KW - Quality assurance KW - Percent within limits ER - TY - JOUR TI - A space-time geostatistical model for probabilistic estimation of harmful algal bloom biomass and areal extent AU - Fang, Shiqi AU - Giudice, Dario Del AU - Scavia, Donald AU - Binding, Caren E. AU - Bridgeman, Thomas B. AU - Chaffin, Justin D. AU - Evans, Mary Anne AU - Guinness, Joseph AU - Johengen, Thomas H. AU - Obenour, Daniel R. T2 - Science of The Total Environment AB - Harmful algal blooms (HABs) have been increasing in intensity worldwide, including the western basin of Lake Erie. Substantial efforts have been made to track these blooms using in situ sampling and remote sensing. However, such measurements do not fully capture HAB spatial and temporal dynamics due to the limitations of discrete shipboard sampling over large areas and the effects of clouds and winds on remote sensing estimates. To address these limitations, we develop a space-time geostatistical modeling framework for estimating HAB intensity and extent using chlorophyll a data sampled during the HAB season (June–October) from 2008 to 2017 by five independent monitoring programs. Based on the Bayesian information criterion for model selection, trend variables explain bloom northerly and easterly expansion from Maumee Bay, wind effects over depth, and variability among sampling methods. Cross validation results demonstrate that space-time kriging explains over half of the variability in daily, location-specific chlorophyll observations, on average. Conditional simulations provide, for the first time, comprehensive estimates of overall bloom biomass (based on depth-integrated concentrations) and surface areal extent with quantified uncertainties. These new estimates are contrasted with previous Lake Erie HAB monitoring studies, and deviations among estimates are explored and discussed. Overall, results highlight the importance of maintaining sufficient monitoring coverage to capture bloom dynamics, as well as the benefits of the proposed approach for synthesizing data from multiple monitoring programs to improve estimation accuracy while reducing uncertainty. DA - 2019/8// PY - 2019/8// DO - 10.1016/j.scitotenv.2019.133776 VL - 8 SP - 133776 KW - Harmful algal blooms KW - Space-time geostatistical model KW - Lake Erie KW - Probabilistic estimates KW - Algal biomass and extent ER - TY - JOUR TI - Influence of Microbe and Enzyme-Induced Treatments on Cemented Sand Shear Response AU - Nafisi, Ashkan AU - Safavizadeh, Shahin AU - Montoya, Brina M. T2 - JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING AB - Microbial-induced calcium carbonate precipitation (MICP) and enzyme-induced calcium carbonate precipitation (EICP) are both soil improvement techniques that improve the shear response of sands. However, the source of urease to hydrolyze the urea is different between the two techniques, and these differences may result in different shear responses. The macro- and microscale behavior of MICP- and EICP-treated sands are evaluated using triaxial tests and scanning electron microscopy (SEM) images. To compare the macroscale behavior, triaxial specimens were treated using MICP and EICP techniques to reach a moderate level of cementation, assessed using shear wave velocity. EICP-treated sand needs less calcium carbonate than MICP-treated sand to reach the same shear wave velocity. The specimens were sheared under drained conditions, and shear responses are compared. The obtained results show that a higher shear strength and larger dilative strain were observed for MICP-treated sand compared to EICP-treated sand when treated to the same shear wave velocity; however, more injections were required for the MICP treatment, which resulted in a higher carbonate content. The SEM images revealed that the shape and structure of precipitated CaCO3 is different in these two treatment techniques, which in turn likely influenced the macroscale response. The advantages of each method are also discussed. DA - 2019/9/1/ PY - 2019/9/1/ DO - 10.1061/(ASCE)GT.1943-5606.0002111 VL - 145 IS - 9 SP - SN - 1943-5606 KW - Bio-mediated techniques KW - Microbially induced CaCO3 precipitation (MICP) KW - Enzyme induced CaCO3 precipitation (EICP) KW - Macro KW - and microscale comparison ER - TY - JOUR TI - Another Look at the Abrasion Resistance of Concrete AU - Park, Sungwoo AU - Pour-Ghaz, Mohammad T2 - ADVANCES IN CIVIL ENGINEERING MATERIALS AB - The abrasion resistance of concrete is considered one of its most important properties in applications such as pavements. Despite the existence of significant amount of research data, the correlation between the abrasion resistance and the compressive strength of concrete remains debatable. This is, in part, due to the limitations of the existing abrasion resistance test methods. We introduce a new abrasion resistance test method that addresses the limitations of the existing test methods; using this new test, we investigate the influence of water-to-cement ratio, coarse aggregate type, and coarse aggregate volume fraction on the abrasion resistance of concrete. We also investigate whether a correlation exists between compressive strength and abrasion resistance of concrete. DA - 2019/// PY - 2019/// DO - 10.1520/ACEM20180159 VL - 8 IS - 1 SP - 423-434 SN - 2165-3984 KW - abrasion resistance KW - cement paste KW - compressive strength KW - concrete ER - TY - JOUR TI - Microbial induced calcium carbonate precipitation in coal ash AU - Safavizadeh, Shahin AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - Géotechnique AB - The long-term storage of coal ash in impoundments can lead to concerns of structural stability as well as trace element migration to local surface water and groundwater sources. Microbial induced calcium carbonate precipitation (MICP) offers a potential approach for minimising leachability of heavy metal trace elements from coal ash by calcium carbonate cementation. In this study, a protocol for MICP treatment of coal ash has been experimentally developed. The MICP treatment is applied to three coal ashes from different power plants, and their response to the developed treatment protocol is assessed. Possible factors affecting the MICP treatment of coal ash are discussed in terms of efficacey and inhibition of the stabilisation process. For this purpose, several approaches such as shear wave velocity, electrical conductivity, pH measurement, acid washing, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were implemented. The results indicated that carbon/carbide content of the fly ash material has an important role in the efficacey of the MICP treatment process. The most likely explanation is carbon/carbide aids in the nucleation of calcium carbonate precipitation. DA - 2019/8// PY - 2019/8// DO - 10.1680/jgeot.18.P.062 VL - 69 IS - 8 SP - 727-740 J2 - Géotechnique LA - en OP - SN - 0016-8505 1751-7656 UR - http://dx.doi.org/10.1680/jgeot.18.P.062 DB - Crossref KW - geomorphology KW - ground improvement KW - industrial wastes KW - laboratory tests KW - mineralogy KW - particle-scale behaviour KW - remediation KW - soil stabilisation ER - TY - JOUR TI - Strain-Level Determination Procedure for Small-Specimen Cyclic Fatigue Testing in the Asphalt Mixture Performance Tester AU - Lee, Kangjin “Caleb” AU - Pape, Sonja AU - Castorena, Cassie AU - Underwood, B. Shane AU - Kim, Y. Richard T2 - Transportation Research Record: Journal of the Transportation Research Board AB - With an increase in small-specimen cyclic fatigue testing using the Asphalt Mixture Performance Tester (AMPT), researchers have observed that the strain-selection guidelines in AASHTO TP 107-14 that are intended for large AMPT cyclic fatigue tests are inadequate for testing small specimens. The machine compliance factor is significantly different for testing small specimens compared with large specimens because of different required load levels, resulting in a significant offset in the relationship between the input strain and the number of cycles to failure. To this end, this paper presents the development and verification of a phenomenological model that relates strain levels to dynamic modulus and number of cycles to failure for small-specimen AMPT cyclic fatigue tests, as well as the development of a corresponding stepped strain-level determination procedure that takes into account cases when the initially selected strain-level results in an unexpected number of cycles to failure. The final procedure includes a table with input strain levels and step strain increments for a wide range of dynamic modulus values as well as a flow chart to guide the use of the step strain adjustment procedure. DA - 2019/6/21/ PY - 2019/6/21/ DO - 10.1177/0361198119845357 SP - 036119811984535 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198119845357 DB - Crossref ER - TY - JOUR TI - Modeling biophysical controls on hypoxia in a shallow estuary using a Bayesian mechanistic approach AU - Katin, Alexey AU - Giudice, Dario Del AU - Obenour, Daniel R. T2 - Environmental Modelling & Software AB - This study describes development of a mechanistically parsimonious model to dynamically simulate bottom layer (subpycnocline) dissolved oxygen (BLDO) concentration in the Neuse River Estuary, USA (1997–2015). The approach embeds differential equations controlling May–October BLDO within a Bayesian framework, enabling rigorous uncertainty quantification considering prior knowledge and calibration to historical data. Model simulations explain 62% of variability in bimonthly mean BLDO observations. Results indicate that during July–August, 36% of BLDO is consumed meeting oxygen demand associated with seasonal primary production, while the rest is depleted meeting long-term oxygen demand (LTOD), associated with storage of organic matter in estuary sediments. Interannual LTOD variation is associated with November–April longitudinal velocities, suggesting elevated flushing in winter decreases oxygen demands in summer. Results also indicate that the system is more responsive to nutrient loading reductions than previously thought, though it may take multiple years to produce measurable declines in hypoxia due to hydro-meteorological variability. DA - 2019/7// PY - 2019/7// DO - 10.1016/j.envsoft.2019.07.016 VL - 7 KW - Hypoxia KW - Dissolved oxygen modeling KW - Bayesian inference KW - Neuse River estuary KW - Stratification KW - Oxygen demand ER - TY - JOUR TI - Supported Liquid Membranes in Pharmaceutics and Biotechnology AU - Hao, Zisu AU - Ho, W. S. Winston T2 - CURRENT TRENDS AND FUTURE DEVELOPMENTS ON (BIO-) MEMBRANES: MEMBRANE PROCESSES IN THE PHARMACEUTICAL AND BIOTECHNOLOGICAL FIELD AB - Pharmaceutics and biotechnology play a vital role for both human beings and the environment. In pharmaceutics and biotechnology, separation processes, using supported liquid membranes (SLMs) in particular, are extensively applied for the removal and recovery of active ingredients from diluted aqueous solutions produced by fermentation and/or enzymatic synthesis. This chapter reviews the significant advances and widespread activities of SLMs in pharmaceutics and biotechnology, especially for the selective removal and recovery of antibiotics such as Cephalexin, Cephalosporin C, Penicillin G, and Amoxicillin. Important parameters that impact the mass transfer performance of SLMs are discussed and highlighted. Future perspectives on the development of SLMs are also highlighted. DA - 2019/// PY - 2019/// DO - 10.1016/B978-0-12-813606-5.00009-9 SP - 259-289 ER - TY - JOUR TI - A Framework of Human-Motion Based Structural Dynamics Simulation Using Mobile Devices AU - Yoon, Hyungchul AU - Han, Kevin AU - Ham, Youngjib T2 - Sensors AB - Due to the nature of real-world problems in civil engineering, students have had limited hands-on experiences in structural dynamics classes. To address this challenge, this paper aims to bring real-world problems in structural dynamics into classrooms through a new interactive learning tool that promotes physical interaction among students and enhances their engagement in classrooms. The main contribution is to develop and test a new interactive computing system that simulates structural dynamics by integrating a dynamic model of a structure with multimodal sensory data obtained from mobile devices. This framework involves integrating multiple physical components, estimating students' motions, applying these motions as inputs to a structural model for structural dynamics, and providing students with an interactive response to observe how a given structure behaves. The mobile devices will capture dynamic movements of the students in real-time and take them as inputs to the dynamic model of the structure, which will virtually simulate structural dynamics affected by moving players. Each component of synchronizing the dynamic analysis with motion sensing is tested through case studies. The experimental results promise the potential to enable complex theoretical knowledge in structural dynamics to be more approachable, leading to more in-depth learning and memorable educational experiences in classrooms. DA - 2019/7/24/ PY - 2019/7/24/ DO - 10.3390/s19153258 UR - https://doi.org/10.3390/s19153258 KW - structural dynamics KW - educational tool KW - mobile devices KW - motion-based ER - TY - JOUR TI - Characterization of a dimer preparation method for nanoscale organic aerosol AU - Rothfuss, Nicholas E. AU - Petters, Sarah S. AU - Champion, Wyatt M. AU - Grieshop, Andrew P. AU - Petters, Markus D. T2 - AEROSOL SCIENCE AND TECHNOLOGY AB - Nanoscale dimers have application in studies of aerosol physicochemical properties such as aerosol viscosity. These particle dimers can be synthesized using the dual tandem differential mobility analyzer (DTDMA) technique, wherein oppositely charged particle streams coagulate to form dimers that can be isolated using electrostatic filtration. Although some characterization of the technique has been published, a detailed thesis on the modes and theory of operation has remained outside the scope of prior work. Here, we present new experimental data characterizing the output DTDMA size distribution and the physical processes underlying its apparent modes. Key experimental limitations for both general applications and for viscosity measurements are identified and quantified in six distinct types of DTDMA experiments. The primary consideration is the production of an adequate number of dimers, which typically requires high mobility-selected number concentration in the range 25,000–100,000 cm−3. The requisite concentration threshold depends upon the rate of spontaneous monomer decharging, which arises predominately from interactions of the aerosol with ionizing radiation within the coagulation chamber and is instrument location dependent. Lead shielding of the coagulation chamber reduced the first-order decharging constant from ∼2.0 × 10−5 s−1 to ∼0.8 × 10−5 s−1 in our laboratory. Dimer production at monomer diameters less than 40 nm is hindered by low bipolar charging efficiency. Results from the characterization experiments shed light on design considerations for general applications and for characterization of viscous aerosol phase transitions.Copyright © 2019 American Association for Aerosol Research DA - 2019/9/2/ PY - 2019/9/2/ DO - 10.1080/02786826.2019.1623379 VL - 53 IS - 9 SP - 998-1011 SN - 1521-7388 UR - https://doi.org/10.1080/02786826.2019.1623379 KW - Pramod Kulkarni ER - TY - JOUR TI - Evaluation of optimal model parameters for prediction of methane generation from selected US landfills AU - Sun, Wenjie AU - Wang, Xiaoming AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. T2 - WASTE MANAGEMENT AB - In practice, methane generation at U.S. landfills is typically predicted by using the EPA's Landfill Gas Emissions Model (LandGEM), which includes two parameters, the methane production potential (L0, m3 CH4 Mg-1 wet waste) and the first-order decay rate constant (k, yr-1). Default parameters in LandGEM (L0 = 100 and k = 0.04) were determined using data that reflect landfill management practices in the 1990s. In this study, methane collection data from 21 U.S. landfills were used to estimate the best fit k by inverse modeling of measured methane collection data in consideration of a time-varying gas collection efficiency. Optimal values of k were identified at a range of L0s between 55 and 160. The best fit k was greater than the U.S. EPA's default parameter of 0.04 yr-1 at 14 of the 21 landfills studied. Surprisingly, the best fit k was often observed at L0 values greater than 100 m3 CH4 Mg-1 wet waste which again is the U.S. EPA default. The results show that there is wide variation in the best estimate of k. While there was a tendency for landfills, or sections of landfills that received more moisture to exhibit higher decay rates, the results were not consistent. Some landfills exhibited high decay rates even though the data suggested that they were relatively dry while some wet landfills exhibited low decay rates. The results suggest that L0 captures many factors and that the data may be most useful for site specific analysis as opposed to general landfill predictions. DA - 2019/5/15/ PY - 2019/5/15/ DO - 10.1016/j.wasman.2019.05.004 VL - 91 SP - 120-127 SN - 0956-053X KW - Landfills KW - Landfill gas KW - Methane KW - Gas collection efficiency KW - LandGEM ER - TY - JOUR TI - The Performance of Super Absorbent Polymer (SAP) Water-Retaining Asphalt Mixture AU - Geng, Jiuguang AU - Chen, Mingyuan AU - Shang, Tao AU - Li, Xun AU - Kim, Y. Richard AU - Kuang, Dongliang T2 - MATERIALS AB - Lowering the temperature of the road surface is one efficient way to alleviate the urban heat island effect. Therefore water-retaining asphalt mixture was produced by adding super absorbent polymer (SAP) containing cement mortar to the porous asphalt mixture. In this study, the water absorption capacity, mechanical strength and fluidity of the cured water-retaining mortar were investigated to determine the optimum SAP dosage in water-retaining mortar. Furthermore, the microstructure of the hardened water-retaining mortar was studied using scanning electron microscopy (SEM) to determine the morphology and distribution of SAP in the final product, which may help to understand the influence of SAP on water retention performance and decipher its underlying mechanism. Compared to the raw porous asphalt mixture, the water-retaining asphalt mixture showed good moisture susceptibility (retained stability (RS) ≥ 88.2%, tensile strength ratio (TSR) ≥ 81.8%), good rutting resistance (9336-10,552 times/mm) and low temperature crack resistance (3383-3621 MPa), as well as significant cooling effects (10-12 °C). The results illustrate that the prepared SAP water-retaining asphalt mixture has good potential in reducing dust and enhancing road performance. DA - 2019/6/2/ PY - 2019/6/2/ DO - 10.3390/ma12121964 VL - 12 IS - 12 SP - SN - 1996-1944 KW - SAP mortar KW - porous asphalt mixture KW - water-retaining KW - microstructure ER - TY - JOUR TI - Efficiency of accelerated techniques for assessing corrosion protection of blended cements AU - Sharkawi, Aladdin M. AU - Seyam, Ahmed M. T2 - MAGAZINE OF CONCRETE RESEARCH AB - The efficiency of different accelerated corrosion techniques was compared to evaluate the role of some blended cements in corrosion protection for reinforced-concrete elements exposed to chloride. Specifically, a quick impressed voltage accelerated corrosion technique was implemented and compared with slower macrocell techniques, such as southern exposure and cracked beam. For the same purpose, corrosion protection performance was also evaluated for reinforced-concrete slabs made with identical cement blends and exposed to severe freely corroding conditions for 140 weeks. Corrosion results for the impressed voltage technique were remarkably comparable to those obtained for the other, slower, corrosion techniques investigated. Therefore, instead of using more complicated techniques, the impressed voltage technique can prove reliable for assessing the chloride-induced corrosion activity of cementitious materials with noticeable differences in durability characteristics. However, further research is currently underway to verify the repeatability of the latter conclusion. Based on the impressed voltage technique, an empirical equation is proposed to predict the delay in steel corrosion initiation obtained by replacing Portland cement with blended cements. The proposed equation depends on some easily measured durability characteristics of concrete surrounding steel. Further research results and data published in the literature can be used to refine the proposed equation. DA - 2019/6// PY - 2019/6// DO - 10.1680/jmacr.17.00269 VL - 71 IS - 12 SP - 637-646 SN - 1751-763X KW - cement KW - cementitious materials KW - durability-related properties KW - reinforcement ER - TY - JOUR TI - Characterization of surface free energy of mineral filler by spreading pressure approach AU - Zhang, Derun AU - Luo, Rong AU - Zeng, Zhe T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Surface free energy of mineral filler plays an important role in evaluating the adhesion of asphalt mastic (mineral filler plus asphalt binder), which is usually measured through the capillary rise approach. However, this approach has been verified to hold only for the low energy materials, which does not apply to the high energy mineral filler. To overcome this limitation, the paper devises a new approach for measuring the surface free energy of the mineral filler based on a generalized Washburn equation. First, a reference liquid is selected to conduct the vapor adsorption test on the mineral filler to measuring its spreading pressure, in which a modified Brunauer-Emmett-Teller (BET) model is employed to determine the filler specific surface area. This reference liquid is again used to perform the capillary rise measurement to calculate the resultant effective capillary radius of the filler bed. Three independent liquids are subsequently selected to conduct the capillary rise test to measure their spreading pressure values with respect to the same mineral filler. By substituting the measured spreading pressure values of the three liquids into the Good-van Oss-Chaudhury (GvOC) equation, the surface free energy components of the mineral filler are finally determined. This newly developed approach is then successfully applied to measure the surface free energy for four typical types of the mineral filler. The moisture susceptibility rankings obtained from the energy ratios of the proposed approach are experimentally found to be consistence with those measured from a standard moisture susceptibility test for the corresponding asphalt mastics. In this regard, the proposed approach is believed to be capable of accurately characterizing the surface free energy of the mineral filler. DA - 2019/9/10/ PY - 2019/9/10/ DO - 10.1016/j.conbuildmat.2019.05.128 VL - 218 SP - 126-134 SN - 1879-0526 KW - Surface free energy KW - Mineral filler KW - Spreading pressure KW - Generalized Washburn equation KW - Modified BET model KW - Capillary rise test KW - Vapor adsorption test ER - TY - JOUR TI - Fatigue damage evolution model of asphalt mixture considering influence of loading frequency AU - Zhang, Jun AU - Wang, Yizhuang David AU - Su, Yongtao T2 - CONSTRUCTION AND BUILDING MATERIALS AB - In view of shortcomings for the traditional fatigue theory in addressing fatigue cracking distress of asphalt pavement, this paper attempts to adopt fatigue damage theory, which is more consistent with the essence of pavement fatigue distress, to study the fatigue damage characteristic of asphalt mixture, and mainly focuses on its pivotal content—damage evolution model. Considering the important influence of loading frequency on the fatigue life and damage evolution characteristics of asphalt mixture, a new damage evolution model is constructed by introducing the influence of loading frequency into the classical Chaboche damage evolution model, as well as the theoretical analysis and laboratory tests are used to analyze and verify the model proposed in the paper. The results show that the calculated results of the model agree well with the measured, which can not only reflect the basic law of damage evolution and accumulation for asphalt mixture, but also reflect the influence of loading frequency on fatigue damage characteristics of mixture. Consequently, it is worthy of further application and promotion in the research of fatigue damage of asphalt pavement. DA - 2019/9/10/ PY - 2019/9/10/ DO - 10.1016/j.conbuildmat.2019.05.029 VL - 218 SP - 712-720 SN - 1879-0526 KW - Asphalt mixture KW - Damage evolution model KW - Loading frequency KW - Fatigue damage ER - TY - JOUR TI - Effect of MSCR Percent Recovery on Performance of Polymer Modified Asphalt Mixtures AU - Salim, Ramadan AU - Gundla, Akshay AU - Underwood, B. Shane AU - Kaloush, Kamil E. T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The AASHTO M332 specification includes a relationship between the non-recoverable creep compliance at 3.2 kPa ( J nr 3.2 ) and the percent of elastic recovery ( R 3.2 ) from the multiple stress creep and recovery (MSCR) test. Justification for the exact position of this curve based on binder performance is largely undocumented in the technical literature as is the singular effect of higher or lower R 3.2 values on mixture performance. In this study, nine binders were tested to evaluate the effect of R 3.2 on the performance of asphalt mixtures. Binders with similar J nr 3.2 and varying MSCR R 3.2 were divided into four groups based on their J nr 3.2 value. Comparisons were made based on results obtained from the dynamic modulus test, Hamburg wheel tracking test, and axial fatigue test. Based on these tests, it was shown that R 3.2 had a strong relationship to the dynamic modulus of asphalt mixtures especially at intermediate and high temperatures. Binders with lower R 3.2 had a higher dynamic modulus but showed no correlation to phase angle. Both modulus and phase angle of the mixture correlated to the binder shear modulus and phase angle. Binders with high R 3.2 had a greater fatigue resistance and the effect is quite noticeable. However, R 3.2 was shown to have little to no effect on the rutting resistance of the asphalt mixtures for the temperatures tested in this study. Finally, an alternative J nr 3.2 versus R 3.2 relationship based on the results of this study is also presented. DA - 2019/4/8/ PY - 2019/4/8/ DO - 10.1177/0361198119841283 VL - 2673 IS - 5 SP - 308-319 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.1177/0361198119841283 DB - Crossref ER - TY - JOUR TI - Lane Change Rates at Freeway Weaving Sites: Trends in HCM6 and from NGSIM Trajectories AU - Ahmed, Ishtiak AU - Xu, Dezhong AU - Rouphail, Nagui AU - Karr, Alan T2 - TRANSPORTATION RESEARCH RECORD AB - Concerns have been raised about the HCM6 weaving method’s lack of sensitivity to weaving segment length. This study explores the trends in HCM6 as they relate to lane change estimates and their impact on the segment speed and level of service (LOS). The study also compares HCM6 estimates of lane changes against empirical data from an NGSIM weaving site. Thus, the objectives of this study are twofold: ( a) critically investigate the effect of weaving length on lane change and associated speed model estimates in HCM6, and ( b) analyze trends in lane changes against congestion levels using detailed NGSIM trajectory data, comparing against HCM6 estimates. For ( a) it was found that the lack of sensitivity to weave length is because of the absence of this parameter in the nonweaving lane change and speed models. For ( b), a comparison of HCM6 lane change rates with NGSIM, US-101 data confirmed that the HCM6 estimates for weaving vehicles are fully consistent with those at the NGSIM site, controlling for density. In contrast, nonweaving lane change estimates in HCM6 did not deliver the expected trends, with more discretionary lane changes predicted as congestion increased. Finally, analysis of lane change patterns at the NGSIM site revealed a tendency for early merging for freeway to ramp traffic and uniform merging for ramp to freeway traffic over the length of the weave. Interestingly, a speed analysis showed that in most cases, a higher frequency of discretionary lane changes yielded lower travel times for drivers executing them. DA - 2019/5// PY - 2019/5// DO - 10.1177/0361198119841281 VL - 2673 IS - 5 SP - 627-636 SN - 2169-4052 ER - TY - JOUR TI - Non-point source evaluation of groundwater nitrate contamination from agriculture under geologic uncertainty AU - Ayub, Riyana AU - Messier, Kyle P. AU - Serre, Marc L. AU - Mahinthakumar, Kumar T2 - STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT DA - 2019/6// PY - 2019/6// DO - 10.1007/s00477-019-01669-z VL - 33 IS - 4-6 SP - 939-956 SN - 1436-3259 KW - Non-point source pollution KW - Nitrate concentration KW - Uncertainty parameters KW - MCMC algorithm ER - TY - JOUR TI - Field measurements of emulsion application rates and pavement emulsion absorption in tack coats and chip seals AU - Malladi, Haritha AU - Castorena, Cassie T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Abstract Simple and practical test frameworks for field measurements of Emulsion Application Rates (EARs) in chip seal and tack coat applications are identified. The methods identified allow for local in situ measurements of the EAR that can be obtained during construction. For both tack coats and chip seals, the test methods identified allow for determining the EAR from residual binder application rate measurements combined with the emulsion water content. Implementation of the test frameworks established in this study could be used as part of a quality assurance/quality control program. DA - 2019/9/10/ PY - 2019/9/10/ DO - 10.1016/j.conbuildmat.2019.05.105 VL - 218 SP - 701-711 SN - 1879-0526 UR - https://doi.org/10.1016/j.conbuildmat.2019.05.105 KW - Tack coat KW - Chip seal KW - Emulsion application rate KW - In situ KW - Field measurements KW - And quality assurance/quality control ER - TY - JOUR TI - Effects of Co-occurring Species Present in Swine Lagoons on Adsorption of Copper on Eggshell AU - Hess, Brianna J. AU - Kolar, Praveen AU - Classen, John J. AU - Knappe, Detlef AU - Cheng, Jay J. T2 - INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH DA - 2019/8// PY - 2019/8// DO - 10.1007/s41742-019-00203-x VL - 13 IS - 4 SP - 613-622 SN - 2008-2304 KW - Adsorption KW - Eggshell KW - Copper KW - Swine lagoons KW - Acetate KW - Ammonia ER - TY - JOUR TI - Effect of Air-Conditioning on Light Duty Gasoline Vehicles Fuel Economy AU - Khan, Tanzila AU - Frey, H. Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - With more stringent U.S. fuel economy (FE) standards, the effect of auxiliary devices such as air-conditioning (AC) have received increased attention. AC is the largest auxiliary engine load for light duty gasoline vehicles (LDGVs). However, there are few data regarding the effect of AC operation on FE for LDGVs based on real-world measurements, especially for recent model year vehicles. The Motor Vehicle Emission Simulator (MOVES) is a regulatory model for estimating on-road vehicle energy-use and emissions. MOVES adjusts vehicle energy-use rates for AC effects. However, MOVES-predicted FE with AC has not been evaluated based on empirical measurements. The research objectives are to quantify the LDGVs FE penalty from AC and assess the accuracy of MOVES2014a-predicted FE with AC. The AC effect on real-world fleet-average FE was quantified based on 78 AC-off vehicles versus 55 AC-on vehicles, measured with onboard instruments on defined study routes. MOVES2014a-based FE penalty from AC was evaluated based on real-world estimates and chassis dynamometer-based FE test results used for FE ratings. The real-world FE penalty ranges between 1.3% and 7.5% among a wide range of driving cycles. Fuel consumption at idle is 13% higher with AC on. MOVES underestimates the real-world FE with AC by 6%, on average. MOVES overestimates the AC effect on cycle-average FE ranging between 13.5% and 18.5% for real-world and MOVES default cycles, and between 11.1% and 14.5% for standard cycles. DA - 2019/5// PY - 2019/5// DO - 10.1177/0361198119838507 VL - 2673 IS - 5 SP - 131-141 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85063930471&partnerID=MN8TOARS ER - TY - JOUR TI - Quantification of Energy Saving Potential for A Passenger Train Based on Inter-Run Variability in Speed Trajectories AU - Yuan, Weichang AU - Frey, H. Christopher AU - Rastogi, Nikhil T2 - TRANSPORTATION RESEARCH RECORD AB - Passenger train energy consumption is dependent on speed trajectories. The variability of passenger train energy consumption owing to the variability in speed trajectories can help identify ways to reduce train energy use via improved operations. Empirical fuel use data from a portable measurement emission measurement system (PEMS) and empirical speed trajectories measured using a global positioning system (GPS) receiver were used to verify and quantify real-world energy consumption variability and the variability in empirical speed trajectories, respectively. To identify potential realistic speed trajectories that can lead to energy saving (i.e., eco-driving), a Markov chain based speed trajectory simulator was used to simulate inter-run variability in speed trajectories. An energy index model (EIM) was used to compare energy consumption among different speed trajectories. The results show inter-run variability in fuel use associated with inter-run variability in the empirical speed trajectories. There is also inter-segment variability in fuel use related to the segment length and grade. The Markov chain based speed trajectory simulator can simulate realistic inter-run variability in speed trajectories based on calibration using empirical speed trajectories. The number of empirical speed trajectories used for simulator calibration affects the range of simulated inter-run variability. The EIM provides an accurate estimation of the empirical fuel use. Eco-driving, such as reducing the peak speed, can reduce energy consumption without compromising travel time. The methodology shown in this study is not system-specific and can be applied to other passenger train systems. DA - 2019/5// PY - 2019/5// DO - 10.1177/0361198119838516 VL - 2673 IS - 5 SP - 153-165 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85063956284&partnerID=MN8TOARS ER - TY - JOUR TI - Anchor Bolt Patterns for Mechanically Fastened FRP Plates AU - McCoy, Brad C. AU - Bourara, Zakariya AU - Seracino, Rudolf AU - Lucier, Gregory W. T2 - JOURNAL OF COMPOSITES FOR CONSTRUCTION AB - This paper examines the results of material testing of hybrid carbon and glass fiber-reinforced polymer (FRP) plates for use in prestressed mechanically fastened applications. The small-scale material tests were conducted in three phases: (1) uniaxial tension without holes, (2) uniaxial tension with open holes, and (3) uniaxial tension with single- and multibolt connections. In all three phases of testing, Digital Image Correlation (DIC) was used to obtain continuous strain data, showing holistic strain field development through failure. A total of 89 tests were conducted across 17 treatment groups to develop an anchor pattern and fastener spacing which is optimized with respect to maximum capacity and behavior under anticipated service load conditions. The tests presented comprise the initial phase of a larger project that aims to employ prestressed mechanically fastened FRP (MF-FRP) plates as a retrofit repair solution for deteriorated prestressed concrete bridge superstructures. Results conclude that 2 lines of 11 bolts with diameters of 12.7 mm, with longitudinal spacing of 100 mm and transverse spacing of 38 mm, provide an end-region anchor pattern with an ultimate capacity of 206 kN which is 89% of the ultimate capacity for the examined FRP plate with holes. DA - 2019/8/1/ PY - 2019/8/1/ DO - 10.1061/(ASCE)CC.1943-5614.0000951 VL - 23 IS - 4 SP - SN - 1943-5614 UR - https://doi.org/10.1061/(ASCE)CC.1943-5614.0000951 KW - Strengthening and repair KW - Mechanically fastened FRP KW - Digital image correlation ER - TY - JOUR TI - Performance Evaluation of Surface-Activated Solid-State Welding for ASTM A992 Structural Steel AU - Morrison, Machel L. AU - Gould, Jerry AU - Charit, Indrajit AU - Hassan, Tasnim T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - This paper presents the results of a pilot study to evaluate a solid-state welding technology, called surface activated solid-state (SASS) welding, for joining structural steel members. SASS welding does not require bulk melting of base metals and can be readily automated to produce high quality joints free from volumetric flaws and without extensive operator training. In addition, this welding process is performed instantly over a plane, in contrast to sequentially along lines as in arc welding; consequently, the former achieves much higher production rates than the latter. Butt-welded joints constructed from A992 steel were SASS welded and subjected to a series of mechanical tests and metallurgical evaluations. Coupon test results indicate that the SASS-welded joints can overmatch the tensile strength and match the ductility of the base metal. However, in the as-welded condition, SASS-welded joints did not display sufficient notch toughness for use in demand critical applications. A metallurgical study of these joints suggests that coarse prior austenite grains, brittle secondary phases, and the texture of grain boundary ferrite at or near the joint interface were possible causes. Notch toughness of SASS welds was significantly improved by post-weld heat-treatment, particularly at temperatures higher than Ac3, which were observed to homogenize the microstructure across the weld joint, refine ferrite grains, and produce purely reconstructive phase transformation products (i.e., polygonal ferrite + pearlite). The improvement in notch toughness is believed to be a result of these microstructural changes. DA - 2019/// PY - 2019/// DO - 10.1061/(ASCE)MT.1943-5533.0002805 VL - 31 IS - 8 ER - TY - JOUR TI - High Temperature Co-pyrolysis Thermal Air Activation Enhances Biochar Adsorption of Herbicides from Surface Water AU - Kearns, Joshua P. AU - Shimabuku, Kyle K. AU - Knappe, Detlef R. U. AU - Summers, R. Scott T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - Recent interest has arisen in the use of biochar as a low-cost adsorbent for control of organic micropollutants in water. However, compared with activated carbon (AC), biochar adsorption capacity is typically one to two orders of magnitude lower. This study reports batch mode adsorption of anionic (2,4-D, C0 100 μg/L) and neutral (simazine [SZN], C0 1.5 μg/L) herbicides from surface water containing dissolved organic matter at 4 mg/L total organic carbon concentration. Enhanced adsorption was observed by biochars generated from updraft gasifiers under conditions of simultaneous co-pyrolysis thermal air activation (CPTA). 2,4-D adsorption by ≥850°C CPTA biochars was more than 10 times greater on a mass basis compared with biochars generated from a conventional anoxic pyrolysis (CAP) reactor and was equivalent to AC reference adsorbents on a surface area normalized basis. Biochars generated at ≥850°C under CPTA conditions had similar micropore surface area to CAP biochars (∼330 m2/g) but about 2.5 times the mesopore surface area (∼110 m2/g CPTA, ∼40 m2/g CAP), suggestive of increased pore accessibility generated by thermochemical widening of pores and/or removal of pyrolysis tars by CPTA. 2,4-D adsorption from surface water was shown to correlate strongly with biochar H:C molar ratio within but not between biochars grouped by CAP and CPTA generation conditions. Comparing adsorption of 2,4-D and SZN by biochars generated from CAP and CPTA conditions suggested that herbicide interaction with biochar surface functional groups through formation of charge-assisted H-bonds did not play a significant role in herbicide uptake from surface water. DA - 2019/6/1/ PY - 2019/6/1/ DO - 10.1089/ees.2018.0476 VL - 36 IS - 6 SP - 710-723 SN - 1557-9018 KW - 2 KW - 4-D KW - adsorption KW - aerobic pyrolysis KW - biochar KW - simazine ER - TY - JOUR TI - Assessing traffic-related environmental impacts based on different traffic monitoring applications AU - Teixeira, Joao AU - Macedo, Eloisa AU - Fernandes, Paulo AU - Bandeira, Jorge M. AU - Rouphail, Nagui AU - Coelho, Margarida C. T2 - 21ST EURO WORKING GROUP ON TRANSPORTATION MEETING (EWGT 2018) AB - The objective of this study is to propose a methodological approach to assess the capability of different traffic monitoring applications to estimate emissions generated by road traffic. Global Navigation Satellite Systems and traffic data were collected from different roadways in Portugal and Spain. Emissions were estimated through the Vehicle Specific Power concept, and then, data mining tools were explored to reveal patterns hidden on large amount of data (154 000 sec). Finally, the best relationships between traffic variables and emissions are evaluated. Results show a prediction for CO2 emissions of 99% and 98% to NOX. DA - 2019/// PY - 2019/// DO - 10.1016/j.trpro.2018.12.172 VL - 37 SP - 107-114 SN - 2352-1465 KW - Traffic-related environmental impacts KW - Emissions KW - VSP ER - TY - JOUR TI - In situ measurements of emulsion application rates AU - Rawls, Mary AU - Castorena, Cassie T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - The emulsion application rate (EAR) is critical to the performance of tack coats and surface treatments. Current quality assurance and quality control measures for EARs are limited and fail to consider in situ measurements. This study evaluates in situ measures to address transverse and longitudinal variability in applied EARs and pavement emulsion absorption using field experiments. Results demonstrate that the Tack Lifter can be used effectively to measure pavement emulsion absorption rates and to capture longitudinal variability in the applied EAR. The Tack Lifter is a simple, weighted device that is placed on a super-absorbent sheet which absorbs emulsion applied to a pavement or plate. When applied directly to a pavement, the device measures the effective EAR on the pavement, neglecting emulsions absorbed into the paving surface. When applied to a plate placed on the pavement prior to emulsion application, the device measures the total applied EAR. Results indicate emulsion absorption should be quantified prior to construction to guide appropriate adjustment of the target EAR. Applied EARs can vary significantly along the length of paving. Limited results indicate transverse variability is relatively consistent along the length of paving and therefore, should be remedied prior to construction rather than using in situ measurements. DA - 2019/// PY - 2019/// DO - 10.1080/10298436.2017.1347438 VL - 20 IS - 7 SP - 811-819 ER - TY - JOUR TI - Multiphase Procedure to Design District Metered Areas for Water Distribution Networks AU - Pesantez, Jorge E. AU - Berglund, Emily Zechman AU - Mahinthakumar, G. T2 - JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT AB - Dividing a water distribution network into subsystems can improve the efficiency and ease of achieving management goals. Subsystems or district metered areas (DMAs) are isolated control zones with a defined number of entrances and exits. This research presents an automatic approach based on graph theory, optimization, and a heuristic methodology to design DMAs for water systems by minimizing the coefficient of variation of demand similarity among DMAs. The multiphase procedure to design DMAs (MPPDMA) satisfies constraints specified to limit the number of entrances per DMA, meet maximum and minimum pressure at nonzero demand nodes, and maintain water levels of the tanks over extended periods of simulation. MPPDMA is applied to four water networks. The results demonstrate that MPPDMA can improve demand similarity among DMAs. DA - 2019/8/1/ PY - 2019/8/1/ DO - 10.1061/(ASCE)WR.1943-5452.0001095 VL - 145 IS - 8 SP - SN - 1943-5452 UR - https://doi.org/10.1061/(ASCE)WR.1943-5452.0001095 KW - Water distribution systems KW - District metered areas (DMAs) KW - Optimization KW - Water demand ER - TY - JOUR TI - Pellet-Fed Gasifier Stoves Approach Gas-Stove Like Performance during in-Home Use in Rwanda AU - Champion, Wyatt M. AU - Grieshop, Andrew P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Nearly all households in Rwanda burn solid fuels for cooking. A private firm in Rwanda is distributing forced-draft pellet-fed semigasifier cookstoves and fuel pellets. We measured in-use emissions of pollutants including fine particulate matter (PM2.5), organic and elemental carbon (OC, EC), black carbon (BC), and carbon monoxide (CO) in 91 uncontrolled cooking tests (UCTs) of both pellet and baseline (wood; charcoal) stoves. We observed >90% reductions in most pollutant emission factors/rates from pellet stoves compared to baseline stoves. Pellet stoves performed far better than gasifier stoves burning unprocessed wood, and consistent with ISO tiers 4 and 5 for PM2.5 and CO, respectively. Pellet stoves were generally clean, but performance varied; emissions from the dirtiest pellet tests matched those from the cleanest traditional stove tests. Our real-time data suggest that events occurring during ignition and the end of testing (e.g., refueling, char burnout) drive high emissions during pellet tests. We use our data to estimate potential health and climate cobenefits from stove adoption. This analysis suggests that pellet stoves have the potential to provide health benefits far above previously tested biomass stoves and approaching modern fuel stoves (e.g., LPG). Net climate impacts of pellet stoves range from similar to LPG to negligible, depending on biomass source and upstream emissions. DA - 2019/6/4/ PY - 2019/6/4/ DO - 10.1021/acs.est.9b00009 VL - 53 IS - 11 SP - 6570-6579 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.9b00009 ER - TY - JOUR TI - Economics of Enhancing Nutrient Circularity in an Organic Waste Valorization System AU - Cobo, Selene AU - Levis, James W. AU - Dominguez-Ramos, Antonio AU - Irabien, Angel T2 - Environmental Science & Technology AB - Waste managers struggle to comply with the European legislation that regulates the handling of organic waste. A waste management system that aims at recovering nutrients from the municipal organic waste generated in the Spanish region of Cantabria was modeled by combining material flow analysis, life cycle assessment, and life cycle costing. The model was optimized to find system configurations that minimize the total annual cost (TAC) and the global warming impacts (GW) and maximize the circularity indicators of nitrogen and phosphorus (CIN and CIP). The developed superstructure is composed of waste management unit processes and unit processes related to the land application of the recovered products (compost, digestate, (NH4)2SO4, and NH4MgPO4·6H2O) and industrial fertilizers to grow corn. The results of the optimization indicate that increasing CIN and minimizing GW raises the TAC, because of the investment in new technologies, although high CIP values can be achieved at low TACs. The economic margin that enables the organic fertilizers to compete in the market with industrial fertilizers was estimated. Cooperation between waste managers, the farmers that purchase the recovered products, and the policy-makers that set the waste management taxes can minimize the costs that hinder the transition toward a circular economy. DA - 2019/5/10/ PY - 2019/5/10/ DO - 10.1021/acs.est.8b06035 VL - 53 IS - 11 SP - 6123-6132 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.8b06035 DB - Crossref ER - TY - JOUR TI - Critical Bending Strain of Reinforcing Steel and Buckled Bar Tension Test AU - Barcley, Leo AU - Kowalsky, Mervyn T2 - ACI Materials 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 - 2019/5// PY - 2019/5// DO - 10.14359/51715583 VL - 116 IS - 3 SP - 53-61 OP - SN - 0889-325X UR - http://dx.doi.org/10.14359/51715583 DB - Crossref KW - critical bending strain KW - fatigue KW - high-strength steel KW - reinforced concrete KW - reinforcing steel KW - seismic design ER - TY - JOUR TI - Effect of Health-Related Uncertainty and Natural Variability on Health Impacts and Cobenefits of Climate Policy AU - Saari, Rebecca K. AU - Mei, Yufei AU - Monier, Erwan AU - Garcia-Menendez, Fernando T2 - Environmental Science & Technology AB - Climate policy can mitigate health risks attributed to intensifying air pollution under climate change. However, few studies quantify risks of illness and death, examine their contribution to climate policy benefits, or assess their robustness in light of natural climate variability. We employ an integrated modeling framework of the economy, climate, air quality, and human health to quantify the effect of natural variability on U.S. air pollution impacts under future climate and two global policies (2 and 2.5 °C stabilization scenarios) using 150 year ensemble simulations for each scenario in 2050 and 2100. Climate change yields annual premature deaths related to fine particulate matter and ozone (95CI: 25 000-120 000), heart attacks (900-9400), and lost work days (3.6M-4.9M) in 2100. It raises air pollution health risks by 20%, while policies avert these outcomes by 40-50% in 2050 and 70-88% in 2100. Natural variability introduces "climate noise", yielding some annual estimates with negative cobenefits, and others that reach 100% of annual policy costs. This "noise" is three times the magnitude of uncertainty (95CI) in health and economic responses in 2050. Averaging five annual simulations reduces this factor to two, which is still substantially larger than health-related uncertainty. This study quantifies the potential for inaccuracy in climate impacts projected using too few annual simulations. DA - 2019/1/9/ PY - 2019/1/9/ DO - 10.1021/acs.est.8b05094 VL - 53 IS - 3 SP - 1098-1108 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.8b05094 DB - Crossref ER - TY - JOUR TI - Natural Variability in Projections of Climate Change Impacts on Fine Particulate Matter Pollution AU - Pienkosz, Bret D. AU - Saari, Rebecca K. AU - Monier, Erwan AU - Garcia‐Menendez, Fernando T2 - Earth's Future AB - Abstract Variations in meteorology associated with climate change can impact fine particulate matter (PM 2.5 ) pollution by affecting natural emissions, atmospheric chemistry, and pollutant transport. However, substantial discrepancies exist among model‐based projections of PM 2.5 impacts driven by anthropogenic climate change. Natural variability can significantly contribute to the uncertainty in these estimates. Using a large ensemble of climate and atmospheric chemistry simulations, we evaluate the influence of natural variability on projections of climate change impacts on PM 2.5 pollution in the United States. We find that natural variability in simulated PM 2.5 can be comparable or larger than reported estimates of anthropogenic‐induced climate impacts. Relative to mean concentrations, the variability in projected PM 2.5 climate impacts can also exceed that of ozone impacts. Based on our projections, we recommend that analyses aiming to isolate the effect climate change on PM 2.5 use 10 years or more of modeling to capture the internal variability in air quality and increase confidence that the anthropogenic‐forced effect is differentiated from the noise introduced by natural variability. Projections at a regional scale or under greenhouse gas mitigation scenarios can require additional modeling to attribute impacts to climate change. Adequately considering natural variability can be an important step toward explaining the inconsistencies in estimates of climate‐induced impacts on PM 2.5 . Improved treatment of natural variability through extended modeling lengths or initial condition ensembles can reduce uncertainty in air quality projections and improve assessments of climate policy risks and benefits. DA - 2019/7/12/ PY - 2019/7/12/ DO - 10.1029/2019EF001195 J2 - Earth's Future LA - en OP - SN - 2328-4277 2328-4277 UR - http://dx.doi.org/10.1029/2019EF001195 DB - Crossref KW - air quality KW - fine particulate matter KW - climate change KW - natural variability ER - TY - JOUR TI - Does Granular Activated Carbon with Chlorination Produce Safer Drinking Water? From Disinfection Byproducts and Total Organic Halogen to Calculated Toxicity AU - Cuthbertson, Amy A. AU - Kimura, Susana Y. AU - Liberatore, Hannah K. AU - Summers, R. Scott AU - Knappe, Detlef R. U. AU - Stanford, Benjamin D. AU - Maness, J. Clark AU - Mulhern, Riley E. AU - Selbes, Meric AU - Richardson, Susan D. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY DA - 2019/// PY - 2019/// DO - 10.1021/acs.est.9600023 VL - 53 IS - 10 SP - 5987-5999 ER - TY - JOUR TI - Comparison of analytical techniques to explain variability in stored drinking water quality and microbial hand contamination of female caregivers in Tanzania AU - Harris, Angela R. AU - Pickering, Amy J. AU - Boehm, Alexandria B. AU - Mrisho, Mwifadhi AU - Davis, Jennifer T2 - ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS AB - Exposure to fecal contamination continues to be a major public health concern for low-income households in sub-Saharan Africa. Drinking water and hands are known transmission routes for pathogens in household environments. In an effort to identify explanatory variables of water and hand contamination, a variety of analytical approaches have been employed that model variation in E. coli contamination as a function of behaviors and household characteristics. Using data collected from 1217 households in Bagamoyo, Tanzania, this investigation compares the explanatory variables identified in the three different modeling methods to explain hand and water contamination: ordinary least squares regression, logistic regression, and classification tree. Although the modeling approaches varied, there were some similarities in the results, with certain explanatory variables being consistently identified as being related to hand and water contamination (e.g., water source type for the water models and activity prior to sampling for the hand models). At the same time, there were also marked differences across the models. In sum, these results suggest there are benefits to using multiple analysis methods to assess relationships in complex systems. The models were also characterized by low explanatory power, suggesting that variation in hand and water contamination is difficult to capture when analyzing one-time water and hand rinse samples. For improved model performance, future studies could explore modeling of repeat measures of water quality and hand contamination. DA - 2019/5/1/ PY - 2019/5/1/ DO - 10.1039/c8em00460a VL - 21 IS - 5 SP - 893-903 SN - 2050-7895 UR - https://doi.org/10.1039/C8EM00460A ER - TY - JOUR TI - An Unstiffened Eight-Bolt Extended End-Plate Moment Connection for Special and Intermediate Moment Frames AU - Morrison, Machel L. AU - Schweizer, Doug Q. AU - Quayyum, Shahriar AU - Hassan, Tasnim T2 - JOURNAL OF STRUCTURAL ENGINEERING AB - Bolted extended end-plate (BEEP) moment-resisting connections are prequalified for use in special and intermediate moment frames. The current limits of this prequalification dictate that rolled wide-flange sections with a depth greater than 601 mm (24 in.) necessitate the use of the stiffened eight-bolt extended end-plate connection. The study reported herein experimentally evaluates an unstiffened eight-bolt extended end-plate connection for seismic applications. The connection features a modified bolt arrangement designed to promote uniform distribution of forces across the bolt group. Plastic hinging of the beam is relocated away from the connection joint by heat-treating selected regions of the beam flanges to reduce the strength of steel. Finally, the beam web is reinforced in the expected plastic hinge region to delay strength degradation due to local buckling. The pilot test specimen exceeded the qualifying 4% interstory drift angle. Failure occurred from buckling-induced fracture in the plastic hinge during loading cycles at 6% interstory drift. In this article, details of experimental development and test results are presented and the connection performance is further analyzed through posttest finite-element simulations. DA - 2019/// PY - 2019/// DO - 10.1061/(ASCE)ST.1943-541X.0002332 VL - 145 IS - 7 ER - TY - JOUR TI - Real-Time Image Localization and Registration with BIM Using Perspective Alignment for Indoor Monitoring of Construction AU - Asadi, Khashayar AU - Ramshankar, Hariharan AU - Noghabaei, Mojtaba AU - Han, Kevin T2 - Journal of Computing in Civil Engineering AB - Construction performance monitoring has been identified as a key component that leads to the success of a construction project. Real-time and frequent monitoring will enable early detection of potential schedule delays and facilitate the communication of progress information accurately and quickly. To facilitate as-built and as-planned data comparison, this paper proposes an automated registration of a video sequence (i.e., a series of image frames) to an as-planned building information model (BIM) in real time. This method discovers the camera poses of image frames in the BIM coordinate system by performing an augmented monocular simultaneous localization and mapping (SLAM) and perspective detecting and matching between the image frames and their corresponding BIM views. The results demonstrate the effectiveness of real-time registration of images with BIMs. The presented method can potentially fully automate past studies that automate progress inference, given visual representation of as-built models aligned with BIM. Moreover, it will facilitate communication on jobsites by associating quality and progress with visuals that are in the BIM coordinate system. DA - 2019/9// PY - 2019/9// DO - 10.1061/(ASCE)CP.1943-5487.0000847 VL - 33 IS - 5 SP - 04019031 UR - https://doi.org/10.1061/(ASCE)CP.1943-5487.0000847 ER - TY - JOUR TI - Addressing how multiple household water sources and uses build water resilience and support sustainable development AU - Elliott, Mark AU - Foster, Tim AU - MacDonald, Morgan C. AU - Harris, Angela R. AU - Schwab, Kellogg J. AU - Hadwen, Wade L. T2 - NPJ CLEAN WATER AB - Abstract The routine use of multiple water sources to meet household water needs is widely practiced and has been reported in many developing countries. However, it is typically neglected by implementers, development organizations, and researchers who tend to focus exclusively on the “main source of drinking water.” In this Perspective, we explain the nature and scope of multiple water source use (MWSU) at the household level in developing countries. We also describe the implications of MWSU for human health and water resilience, and identify key knowledge gaps, risks, and opportunities associated with MWSU. Finally, we argue that understanding MWSU is feasible for researchers and implementers and is essential for properly designing research studies and water supply projects. DA - 2019/3/1/ PY - 2019/3/1/ DO - 10.1038/s41545-019-0031-4 VL - 2 IS - 1 SP - SN - 2059-7037 UR - https://doi.org/10.1038/s41545-019-0031-4 ER - TY - JOUR TI - Model applicability for prediction of residual soil apparent cohesion AU - Tang, Chien-Ting AU - Borden, Roy H. AU - Gabr, Mohammed A. T2 - Transportation Geotechnics AB - The focus of this paper is on the measurement and prediction of unsaturated shear strength of residual soil as a function of matric suction by utilizing basic soil properties. A total of 19 unsaturated triaxial tests were performed on four groups of undisturbed residual soil specimens with different classifications and compositions. Six compacted specimens were tested and showed lower strength values than those of undisturbed specimens. The cohesion intercept due to matric suction was used to represent the strength contribution of the matric suction, thus accounting for the effect of confining pressure and effective cohesion. The feasibility of three existing models in predicting the apparent cohesion is investigated through comparing computed results to measured data from this paper and literature. A proposed regression equation, developed based on four data sets from the current research and six from the literature, shows an improved ability to predict measured apparent cohesion utilizing basic soil properties. The data set developed herein represent a significant addition to the literature on the unsaturated strength properties of natural residual soil, as sampled from the field. DA - 2019/6// PY - 2019/6// DO - 10.1016/j.trgeo.2019.01.003 VL - 19 SP - 44-53 J2 - Transportation Geotechnics LA - en OP - SN - 2214-3912 UR - http://dx.doi.org/10.1016/j.trgeo.2019.01.003 DB - Crossref ER - TY - JOUR TI - Flux modeling for monolignol biosynthesis AU - Wang, Jack P AU - Matthews, Megan L AU - Naik, Punith P AU - Williams, Cranos M AU - Ducoste, Joel J AU - Sederoff, Ronald R AU - Chiang, Vincent L T2 - Current Opinion in Biotechnology AB - The pathway of monolignol biosynthesis involves many components interacting in a metabolic grid to regulate the supply and ratios of monolignols for lignification. The complexity of the pathway challenges any intuitive prediction of the output without mathematical modeling. Several models have been presented to quantify the metabolic flux for monolignol biosynthesis and the regulation of lignin content, composition, and structure in plant cell walls. Constraint-based models using data from transgenic plants were formulated to describe steady-state flux distribution in the pathway. Kinetic-based models using enzyme reaction and inhibition constants were developed to predict flux dynamics for monolignol biosynthesis in wood-forming cells. This review summarizes the recent progress in flux modeling and its application to lignin engineering for improved plant development and utilization. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.copbio.2018.12.003 VL - 56 SP - 187-192 UR - https://doi.org/10.1016/j.copbio.2018.12.003 ER - TY - JOUR TI - Influence of storm timing and forward speed on tides and storm surge during Hurricane Matthew AU - Thomas, Ajimon AU - Dietrich, JC AU - Asher, TG AU - Bell, M AU - Blanton, BO AU - Copeland, JH AU - Cox, AT AU - Dawson, CN AU - Fleming, JG AU - Luettich, RA AU - al., T2 - Ocean Modelling AB - The amount and extent of coastal flooding caused by hurricanes can be sensitive to the timing or speed of the storm. For storms moving parallel to the coast, the hazards can be stretched over a larger area. Hurricane Matthew was a powerful storm that impacted the southeastern U.S. during October 2016, moving mostly parallel to the coastline from Florida through North Carolina. In this study, three sources for atmospheric forcing are considered for a simulation of Matthew's water levels, which are validated against extensive observations, and then the storm's effects are explored on this long coastline. It is hypothesized that the spatial variability of Matthew's effects on total water levels is partly due to the surge interacting nonlinearly with tides. By changing the time of occurrence of the storm, differences in storm surge are observed in different regions due to the storm coinciding with other periods in the tidal cycles. These differences are found to be as large as 1 m and comparable to the tidal amplitude. A change in forward speed of the storm also should alter its associated flooding due to differences in the duration over which the storm impacts the coastal waters. With respect to the forward speed, the present study contributes to established results by considering the scenario of a shore-parallel hurricane. A faster storm caused an increase in peak water levels along the coast but a decrease in the overall volume of inundation. On the other hand, a slower storm pushed more water into the estuaries and bays and flooded a larger section of the coast. Implications for short-term forecasting and long-term design studies for storms moving parallel to long coastlines are discussed herein. DA - 2019/5// PY - 2019/5// DO - 10.1016/j.ocemod.2019.03.004 VL - 137 SP - 1-19 J2 - Ocean Modelling LA - en OP - SN - 1463-5003 UR - http://dx.doi.org/10.1016/j.ocemod.2019.03.004 DB - Crossref KW - ADCIRC KW - SWAN KW - Inundation KW - Hindcasting KW - HSOFS mesh KW - OWI wind fields ER - TY - JOUR TI - Calibration of inertial consistency models on North Carolina two-lane rural roads AU - Llopis-Castello, David AU - Findley, Daniel J. AU - Javier Camacho-Torregrosa, Francisco AU - Garcia, Alfredo T2 - ACCIDENT ANALYSIS AND PREVENTION AB - Road crash occurrence is closely related to the geometric design consistency, which can be defined as how drivers’ expectancies and road behavior fit. To this regard, the crash rate on a road segment increases as its consistency level decreases. To assess this phenomenon, inertial consistency models were recently developed. These models are based on the difference between the inertial operating speed, which represents drivers’ expectancies, and the operating speed, which represents road behavior. The higher the difference between both speeds, the higher the likelihood of crash occurrence. This research aims to validate and calibrate these consistency models on American two-lane rural roads. For this, a total of 194 homogeneous road segments and 977 horizontal curves along 665 km in North Carolina (US) were used. As a result, the geometric design consistency was identified as a major factor of crash occurrence. The higher the difference between drivers’ expectancies and road behavior, the higher the crash rate. Likewise, the greater the consistency level, the greater the percentage of horizontal curves without reported crashes. A Safety Performance Function was also calibrated to estimate the number of crashes on a road segment. Consistency thresholds were defined and tested to identify where these crashes are more likely to take place. Finally, the results obtained in this study were compared with those obtained previously on Spanish highways. To this regard, the crash rate on an American highway was 1.85 times greater than those observed on a Spanish highway under the same risk exposure and consistency conditions. Therefore, different tools were developed to enhance the assessment of road safety to the geometric design of both new two-lane rural roads and improvements of existing highways. DA - 2019/6// PY - 2019/6// DO - 10.1016/j.aap.2019.03.013 VL - 127 SP - 236-245 SN - 1879-2057 KW - Geometric design consistency KW - Road safety KW - Operating speed KW - Inertial operating speed KW - Driver's behavior ER - TY - JOUR TI - The Weather Research and Forecasting Model with Aerosol-Cloud Interactions (WRF-ACI): Development, Evaluation, and Initial Application AU - Glotfelty, Timothy AU - Alapaty, Kiran AU - He, Jian AU - Hawbecker, Patrick AU - Song, Xiaoliang AU - Zhang, Guang T2 - MONTHLY WEATHER REVIEW AB - Abstract The Weather Research and Forecasting Model with Aerosol–Cloud Interactions (WRF-ACI) is developed for studying aerosol effects on gridscale and subgrid-scale clouds using common aerosol activation and ice nucleation formulations and double-moment cloud microphysics in a scale-aware subgrid-scale parameterization scheme. Comparisons of both the standard WRF and WRF-ACI models’ results for a summer season against satellite and reanalysis estimates show that the WRF-ACI system improves the simulation of cloud liquid and ice water paths. Correlation coefficients for nearly all evaluated parameters are improved, while other variables show slight degradation. Results indicate a strong cloud lifetime effect from current climatological aerosols increasing domain average cloud liquid water path and reducing domain average precipitation as compared to a simulation with aerosols reduced by 90%. Increased cloud-top heights indicate a thermodynamic invigoration effect, but the impact of thermodynamic invigoration on precipitation is overwhelmed by the cloud lifetime effect. A combination of cloud lifetime and cloud albedo effects increases domain average shortwave cloud forcing by ~3.0 W m−2. Subgrid-scale clouds experience a stronger response to aerosol levels, while gridscale clouds are subject to thermodynamic feedbacks because of the design of the WRF modeling framework. The magnitude of aerosol indirect effects is shown to be sensitive to the choice of autoconversion parameterization used in both the gridscale and subgrid-scale cloud microphysics, but spatial patterns remain qualitatively similar. These results indicate that the WRF-ACI model provides the community with a computationally efficient tool for exploring aerosol–cloud interactions. DA - 2019/5// PY - 2019/5// DO - 10.1175/MWR-D-18-0267.1 VL - 147 IS - 5 SP - 1491-1511 SN - 1520-0493 ER - TY - JOUR TI - Comparison of real-world vehicle fuel use and tailpipe emissions for gasoline-ethanol fuel blends AU - Yuan, Weichang AU - Frey, H. Christopher AU - Wei, Tongchuan AU - Rastogi, Nikhil AU - VanderGriend, Steven AU - Miller, David AU - Mattison, Lawrence T2 - FUEL AB - Differences in fuel use and emission rates of carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (HC), nitrogen oxide (NOx), and particulate matter (PM) were quantified for three gasoline-ethanol blends and neat gasoline measured for one flexible-fuel vehicle (FFV) and four non-FFVs using a portable emission measurement system (PEMS). The purpose was to determine if non-FFVs can adapt to a mid-level blend and to compare the fuel use and emission rates among the fuels. Each vehicle was measured on neat gasoline (E0), 10% ethanol by volume (E10) “regular” (E10R) and “premium” (E10P), and 27% ethanol by volume (E27). Four real-world cycles were repeated for each vehicle with each fuel. Second-by-second fuel use and emission rates were binned into Vehicle Specific Power (VSP) modes. The modes were weighted according to real-world standard driving cycles. All vehicles, including the non-FFVs, were able to adapt to E27. Octane-induced efficiency gain was observed for higher octane fuels (E10P and E27) versus lower octane fuels (E0 and E10R). E27 tends to lower PM emission rates compared to E10R and E10P and CO emission rates compared to the other three fuels. HC emission rates for E27 were comparable to those of E10R and E10P. No significant difference was found in NOx emission rates for E27 versus the other fuels. Intervehicle variability in fuel use and emission rates was observed. Lessons learned regarding study design, vehicle selection, and sample size, and their implications are discussed. DA - 2019/8/1/ PY - 2019/8/1/ DO - 10.1016/j.fuel.2019.03.115 VL - 249 SP - 352-364 SN - 1873-7153 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85063525708&partnerID=MN8TOARS KW - Ethanol KW - Octane KW - Real-world driving KW - Portable emission measurement system KW - Exhaust emissions ER - TY - JOUR TI - Revisiting Relationships among Specific Surface Area, Soil Consistency Limits, and Group Index of Clays AU - Deng, Yongfeng AU - Liu, Qianwen AU - Cui, Yujun AU - Wang, Qiong AU - Liu, Songyu T2 - JOURNAL OF TESTING AND EVALUATION AB - Investigations correlating specific surface area (SSA) with other soil parameters like consistency limits are helpful in understanding the internal meaning of soil properties. In this study, a large database (267 groups of test results) from the literature is established, and the performed statistical analyses show that the traditional relationship with limited data may be invalid when large data are involved. Hereafter, there is a relatively good relationship between the soil consistency limits and SSA when the threshold SSA value (about 80 m2/g) is identified, which suggests that the soils totally behave as pellets and platelets in the geometry, respectively, before and after this value. Despite the fact that this threshold SSA should complicatedly depend on the crystalline formation, clay mineral, and clay fraction in the particle size distribution, this threshold is relatively reliable in view of these large data statistics. Additionally, the group index by ASTM and the methylene blue value by Laboratoire Centrale des Ponts et Chaussees in France can be mutually converted to characterize subgrade soils to account for the established relationship between consistency limits and SSA. DA - 2019/3// PY - 2019/3// DO - 10.1520/JTE20170257 VL - 47 IS - 2 SP - 1392-1404 SN - 1945-7553 KW - specific surface area KW - soil consistency limit KW - group index KW - clay platelet-water system KW - particle geometry ER - TY - JOUR TI - Influence of Calibration Factors on Crash Prediction on Rural Two-Lane Two-Way Roadway Segments AU - Llopis-Castello, David AU - Findley, Daniel J. T2 - JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS AB - Calibration factors are applied in the Highway Safety Manual predictive method for rural two-lane, two-way roadway segments to adjust the estimate for local conditions. This research aims to evaluate and recommend improvements related to the estimation of these calibration factors. An aggregated and disaggregated analysis was performed to study the influence of different calibration factors on the prediction of the number of crashes in North Carolina. As a result, those calibration factors based on both types of road elements (horizontal curves and tangents) led to overestimating and underestimating the number of crashes on tangents and horizontal curves, respectively. Furthermore, the calibration factors based on fatal and injury crashes allowed a more accurate estimation of the predicted number of crashes than those calibrated considering all severity levels. Therefore, it is recommended to apply different calibration factors for each type of road element and each type of crash severity. DA - 2019/6/1/ PY - 2019/6/1/ DO - 10.1061/JTEPBS.0000245 VL - 145 IS - 6 SP - SN - 2473-2893 ER - TY - JOUR TI - Modeling chloramine decay in full-scale drinking water supply systems AU - Ricca, Henry AU - Aravinthan, Vasanthadevi AU - Mahinthakumar, Gnanamanikam T2 - WATER ENVIRONMENT RESEARCH AB - Abstract Chloramines are commonly used as secondary disinfectants in drinking water treatment, providing a residual for disinfection as drinking water moves to consumers. Chloramines are inherently unstable, undergoing autodecomposition reactions even in the absence of reactive substances. In the presence of natural organic matter ( NOM ), chloramine loss accelerates due to additional reaction pathways. In this study, batch reaction models for chloramine loss due to autodecomposition and the presence of NOM were developed. A case study was carried out for the Town of Cary, North Carolina. A hydraulic model of Cary's distribution system was developed and calibrated using the EPANET toolkit with operational and water demand data supplied by Cary. Then, water age from the hydraulic model was used together with the batch model of chloramine decay to successfully predict chloramine concentrations spatially and temporally throughout the network. The capabilities of the EPANET ‐ MSX toolkit to model chloramine loss in a distribution network are explored. Practitioner points A batch reaction model of chloramine decay over time due to autodecomposition reactions and additional reactions with NOM was developed and validated. A hydraulic model of the Town of Cary’s water distribution network was developed and calibrated using operational and water demand data. Water age reported by the calibrated hydraulic model was used in conjunction with the batch reaction model of chloramine decay to successfully predict chloramine concentrations spatially and temporally throughout the network. DA - 2019/5// PY - 2019/5// DO - 10.1002/wer.1046 VL - 91 IS - 5 SP - 441-454 SN - 1554-7531 KW - chloramine decay KW - EPANET-MSX KW - water distribution KW - water quality modeling ER - TY - JOUR TI - Efficient Preconditioned Soil-Foundation-Structure Interaction Approach to Compute Tall-Building Time Periods AU - Elmeliegy, A. M. AU - Rashed, Youssef F. T2 - PRACTICE PERIODICAL ON STRUCTURAL DESIGN AND CONSTRUCTION AB - The present paper suggests an efficient preconditioned two-iteration substructure approach—namely, preconditioned soil–structure interaction (PSSI)—to couple the analysis of a superstructure over fixed bases (which is traditionally carried out in design companies) with the analysis of foundation plates over an elastic half-space (EHS) to obtain more accurate equivalent supporting spring stiffnesses. Hence, an accurate building time period and, consequently, lateral loads could be computed. The effectiveness of the proposed approach is illustrated in several numerical examples in terms of number of iterations and scalability followed by comparison with previous work to demonstrate the superiority of the proposed approach. DA - 2019/8/1/ PY - 2019/8/1/ DO - 10.1061/(ASCE)SC.1943-5576.0000422 VL - 24 IS - 3 SP - SN - 1943-5576 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85063899035&partnerID=MN8TOARS KW - Soil-structure interaction KW - Iterative coupling KW - Tall buildings KW - Time period KW - Lateral loads KW - Base shear ER - TY - JOUR TI - Debonding of microbially induced carbonate precipitation-stabilized sand by shearing and erosion AU - Do, Jinung AU - Montoya, Brina M. AU - Gabr, Mohammed A. T2 - GEOMECHANICS AND ENGINEERING AB - Microbially induced carbonate precipitation (MICP) is an innovative soil improvement approach utilizing metabolic activity of microbes to hydrolyze urea. In this paper, the shear response and the erodibility of MICP-treated sand under axial compression and submerged impinging jet were evaluated at a low confining stress range. Loose, poorly graded silica sand was used in testing. Specimens were cemented at low confining stresses until target shear wave velocities were achieved. Results indicated that the erodibility parameters of cemented specimens showed an increase in the critical shear stress by up to three orders of magnitude, while the erodibility coefficient decreased by up to four orders of magnitude. Such a trend was observed to be dependent on the level of cementation. The treated sand showed dilative behavior while the untreated sands showed contractive behavior. The shear modulus as a function of strain level, based on monitored shear wave velocity, indicated mineral debonding may commence at 0.05% axial strain. The peak strength was enhanced in terms of emerging cohesion parameter based on utilizing the Mohr-Coulomb failure criteria. DA - 2019/4/10/ PY - 2019/4/10/ DO - 10.12989/gae.2019.17.5.429 VL - 17 IS - 5 SP - 429-438 SN - 2005-307X KW - microbially induced carbonate precipitation (MICP) KW - bio-cementation KW - triaxial testing KW - impinging jet testing KW - erodibility ER - TY - JOUR TI - Undrained cyclic response of silty sands improved by microbial induced calcium carbonate precipitation AU - Zamani, Atefeh AU - Montoya, Brina M. T2 - SOIL DYNAMICS AND EARTHQUAKE ENGINEERING AB - Loose saturated silty sand can be prone to liquefaction but improving their soil properties is challenging due to their lower permeability compared to clean sands. Microbial induced calcium carbonate precipitation (MICP) is a new, natural and sustainable soil improvement method, which can increase the shear strength and stiffness of soils. In this study, MICP treatment is applied to silty sands with fines content in the range of 0–35% and a constant preshear void ratio 0.7 ± 0.05 to observe improvement in their liquefaction resistance. The specimens are treated until reaching a shear wave velocity about 400 m/s. Cyclic direct simple shear testing is used to evaluate changes in the liquefaction resistance of untreated and MICP treated silty sands. The results show that by applying MICP the liquefaction resistance increases significantly for all fines contents tested, and the treatment efficiency depends on the level of fines content, which dictate the relative density, and the fabric governing the structure. As examples, the 35% fines content specimen has shown the highest improvement, which is related to a higher relative density at this fines content. The silty sand specimens with 5% fines content has a metastable structure which makes the soil more sensitive to cyclic loading. Although the cyclic resistance has increased by applying MICP at this level of fines content, its sensitivity to cyclic loading has remained unchanged. The results of this study demonstrate that MICP improves the cyclic strength of silty sand and can provide an alternative soil improvement method for silty sand. DA - 2019/5// PY - 2019/5// DO - 10.1016/j.soildyn.2019.01.010 VL - 120 SP - 436-448 SN - 1879-341X KW - Undrained cyclic response KW - MICP KW - Silty sand KW - Fines content KW - Sporosarcina pasteurii KW - Cementation ER - TY - JOUR TI - Nondestructive Method for Length Estimation of Pile Foundations Through Effective Dispersion Analysis of Reflections AU - Samu, Vivek AU - Guddati, Murthy T2 - JOURNAL OF NONDESTRUCTIVE EVALUATION DA - 2019/6// PY - 2019/6// DO - 10.1007/s10921-019-0583-8 VL - 38 IS - 2 SP - SN - 1573-4862 KW - Unknown foundation KW - Pile KW - Length estimation KW - Flexural waves KW - Reflection ER - TY - JOUR TI - Determinants of Cookstoves and Fuel Choice Among Rural Households in India AU - Menghwani, Vikas AU - Zerriffi, Hisham AU - Dwivedi, Puneet AU - Marshall, Julian D. AU - Grieshop, Andrew AU - Bailis, Rob T2 - ECOHEALTH DA - 2019/3// PY - 2019/3// DO - 10.1007/s10393-018-1389-3 VL - 16 IS - 1 SP - 21-60 SN - 1612-9210 KW - Improved cookstoves (ICS) KW - Household energy transition KW - Biomass KW - LPG KW - Rural India KW - Multinomial regression KW - Logistic regression ER - TY - JOUR TI - Building conflict uncertainty into electricity planning: A South Sudan case study AU - Patankar, Neha AU - Queiroz, Anderson Rodrigo AU - DeCarolis, Joseph F. AU - Bazilian, Morgan D. AU - Chattopadhyay, Debabrata T2 - ENERGY FOR SUSTAINABLE DEVELOPMENT AB - This paper explores electricity planning strategies in South Sudan under future conflict uncertainty. A stochastic energy system optimization model that explicitly considers the possibility of armed conflict leading to electric power generator damage is presented. Strategies that hedge against future conflict have the greatest economic value in moderate conflict-related damage scenarios by avoiding expensive near-term investments in infrastructure that may be subsequently damaged. Model results show that solar photovoltaics can play a critical role in South Sudan's future electric power system. In addition to mitigating greenhouse gas emissions and increasing access to electricity, this analysis suggests that solar can be used to hedge against economic losses incurred by conflict. While this analysis focuses on South Sudan, the analytical framework can be applied to other conflict-prone countries. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.esd.2019.01.003 VL - 49 SP - 53-64 SN - 0973-0826 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060864438&partnerID=MN8TOARS KW - Stochastic programming KW - Conflict uncertainty KW - South Sudan ER - TY - JOUR TI - Analytical approach for global load-slip behaviour of FRP plates externally bonded to brittle substrates with anchors AU - Sturm, A. B. AU - Visintin, P. AU - Vaculik, J. AU - Oehlers, D. J. AU - Seracino, R. AU - Smith, S. T. T2 - COMPOSITES PART B-ENGINEERING AB - A partial interaction procedure is developed for obtaining analytical solutions for the global load-slip behaviour of fibre-reinforced polymer plates adhesively bonded and mechanically anchored to brittle substrates. This is performed by adopting a matrix approach where the slip and slip strain at any point is given by the product of a solution matrix which is a function of: the position; the zone of solution - whether it is elastic, softening or debonding; and a coefficient vector. It is shown that the procedure can be used as a convenient research tool for extracting the material bond properties from standard experimental pull-push tests, or for use in advanced numerical simulations to develop anchorage systems for structures retrofitted with fibre-reinforced polymer (FRP) composites. DA - 2019/3/1/ PY - 2019/3/1/ DO - 10.1016/j.compositesb.2018.10.024 VL - 160 SP - 177-194 SN - 1879-1069 KW - Analytical solutions KW - Debonding KW - Displacement force relation ER - TY - JOUR TI - Improving understanding of carbon storage in wood in landfills: Evidence from reactor studies AU - Ximenes, Fabiano A. AU - Bjordal, Charlotte AU - Kathuria, Amrit AU - Barlaz, Morton A. AU - Cowie, Annette L. T2 - WASTE MANAGEMENT AB - Approximately 1.5 million tonnes (Mt) of wood waste are disposed of in Australian landfills annually. Recent studies have suggested that anaerobic decay levels of wood in landfills are low, although knowledge of the decay of individual wood species is limited. The objective of this study was to establish the extent of carbon loss for wood species of commercial importance in Australia including radiata pine, blackbutt, spotted gum and mountain ash. Experiments were conducted under laboratory conditions designed to simulate optimal anaerobic biodegradation in a landfill. Bacterial degradation, identified by both light microscopy and electron microscopy, occurred to a varying degree in mountain ash and spotted gum wood. Fungal decay was not observed in any wood samples. Mountain ash, the species with the highest methane yield (20.9 mL CH4/g) also had the highest holocellulose content and the lowest acid-insoluble lignin and extractive content. As the decay levels for untreated radiata pine were very low, it was not possible to determine whether impregnation of radiata pine with chemical preservatives had any impact on decay. Carbon losses estimated from gas generation were below 5% for all species tested. Carbon losses as estimated by gas generation were lower than those derived by mass balance in most reactors, suggesting that mass loss does not necessarily equate to carbon emissions. There was no statistical difference between decay of blackbutt derived from plantation and older, natural forests. Addition of paper as an easily digestible feedstock did not increase carbon loss for the two wood species tested and the presence of radiata pine had an inhibitory effect on copy paper decay. Although differences between some of the wood types were found to be statistically significant, these differences were detected for wood with carbon losses that did not exceed 5%. The suggested factor for carbon loss for wood in landfills in Australia is 1.4%. This study confirms that disposal of wood in landfills in Australia results in long-term storage of carbon, with only minimal conversion of carbon to gaseous end products. DA - 2019/2/15/ PY - 2019/2/15/ DO - 10.1016/j.wasman.2019.01.004 VL - 85 SP - 341-350 SN - 0956-053X KW - Wood KW - Carbon KW - Landfill KW - Methane KW - Decay KW - Bacteria ER - TY - JOUR TI - Automated calibration of advanced cyclic plasticity model parameters with sensitivity analysis for aluminium alloy 2024-T351 AU - Pec, Michal AU - Sebek, Frantisek AU - Zapletal, Josef AU - Petruska, Jindrich AU - Hassan, Tasnim T2 - ADVANCES IN MECHANICAL ENGINEERING AB - The plasticity models in finite element codes are often not able to describe the cyclic plasticity phenomena satisfactorily. Developing a user-defined material model is a demanding process, challenging especially for industry. Open-source Code_Aster is a rapidly expanding and evolving software, capable of overcoming the above-mentioned problem with material model implementation. In this article, Chaboche-type material model with kinematic hardening evolution rules and non-proportional as well as strain memory effects was studied through the calibration of the aluminium alloy 2024-T351. The sensitivity analysis was performed prior to the model calibration to find out whether all the material model parameters were important. The utilization of built-in routines allows the calibration of material constants without the necessity to write the optimization scripts, which is time consuming. Obtaining the parameters using the built-in routines is therefore easier and allows using the advanced modelling for practical use. Three sets of material model parameters were obtained using the built-in routines and results were compared to experiments. Quality of the calibration was highlighted and drawbacks were described. Usage of material model implemented in Code_Aster provided good simulations in a relatively simple way through the use of an advanced cyclic plasticity model via built-in auxiliary functions. DA - 2019/3/18/ PY - 2019/3/18/ DO - 10.1177/1687814019829982 VL - 11 IS - 3 SP - SN - 1687-8140 KW - Chaboche kinematic hardening KW - Armstrong-Frederick model KW - Voce isotropic hardening KW - biaxial stress KW - ratcheting KW - multiaxial fatigue ER - TY - JOUR TI - The role of cross-correlation between precipitation and temperature in basin-scale simulations of hydrologic variables AU - Seo, S.B. AU - Das Bhowmik, R. AU - Sankarasubramanian, A. AU - Mahinthakumar, G. AU - Kumar, M. T2 - Journal of Hydrology AB - Uncertainty in climate forcings causes significant uncertainty in estimating streamflow and other land-surface fluxes in hydrologic model simulations. Earlier studies primarily analyzed the importance of reproducing cross-correlation between precipitation and temperature (P-T cross-correlation) using various downscaling and weather generator schemes, leaving out how such biased estimates of P-T cross-correlation impact streamflow simulation and other hydrologic variables. The current study investigates the impacts of biased P-T cross-correlation on hydrologic variables using a fully coupled hydrologic model (Penn-state Integrated Hydrologic Model, PIHM). For this purpose, a synthetic weather generator was developed to generate multiple realizations of daily climate forcings for a specified P-T cross-correlation. Then, we analyzed how reproducing/neglecting P-T cross-correlation in climate forcings affect the accuracy of a hydrologic simulation. A total of 50 synthetic data sets of daily climate forcings with different P-T cross-correlation were forced into to estimate streamflow, soil moisture, and groundwater level under humid (Haw River basin in NC, USA) and arid (Lower Verde River basin in AZ, USA) hydroclimate settings. Results show that climate forcings reproducing the P-T cross-correlation yield lesser root mean square errors in simulated hydrologic variables (primarily on the sub-surface variables) as compared to climate forcings that neglect the P-T cross-correlation. Impacts of P-T cross-correlation on hydrologic simulations were remarkable to low flow and sub-surface variables whereas less significant to flow variables that exhibit higher variability. We found that hydrologic variables with lower internal variability (for example: groundwater and soil-moisture depth) are susceptible to the bias in P-T cross-correlation. These findings have potential implications in using univariate linear downscaling techniques to bias-correct GCM forcings, since univariate linear bias-correction techniques reproduce the GCM estimated P-T cross-correlation without correcting the bias in P-T cross-correlation. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.jhydrol.2018.12.076 VL - 570 SP - 304-314 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/J.JHYDROL.2018.12.076 DB - Crossref KW - Cross-correlation KW - GCM KW - Univariate KW - Bias-correction KW - PIHM KW - Hydrologic simulation ER - TY - JOUR TI - An agent-based modeling approach to project adoption of water reuse and evaluate expansion plans within a sociotechnical water infrastructure system AU - Kandiah, Venu K. AU - Berglund, Emily Z. AU - Binder, Andrew R. T2 - Sustainable Cities and Society AB - The introduction of water reuse infrastructure into an existing water supply system is a complex sociotechnical process. For a dual reticulation program, infrastructure designs affect adoption, as the expansion of infrastructure defines when a household can adopt and become active in communicating about water reuse. This research develops a coupled framework to capture the dynamics among consumer adoption and infrastructure expansion. An agent-based modeling approach is used to simulate opinion dynamics within a risk publics framework, which is based on the social amplification of risk and captures changes in perceptions about the risks and benefits of water reuse. The model is applied to simulate and project adoption of water reuse for the Town of Cary, North Carolina, using data about new water reclamation accounts and plans for infrastructure expansion. Performance of the agent-based model is compared with a cellular automata model for simulating historic data. Alternative infrastructure expansion schedules are simulated using the agent-based model to evaluate potable water savings and utilization of reclaimed water capacity, based on adoption projections. The framework provides a sociotechnical approach to evaluate development plans for infrastructure systems that rely on adoption of infrastructure-dependent technologies. DA - 2019/4// PY - 2019/4// DO - 10.1016/j.scs.2018.12.040 VL - 46 SP - 101412 J2 - Sustainable Cities and Society LA - en OP - SN - 2210-6707 UR - http://dx.doi.org/10.1016/j.scs.2018.12.040 DB - Crossref KW - Complex adaptive system KW - Diffusion of innovations KW - Dual water system KW - Sociotechnical transition KW - Urban water management KW - Water reuse KW - Eco-innovation ER - TY - JOUR TI - LNSNet: Lightweight Navigable Space Segmentation for Autonomous Robots on Construction Sites AU - Asadi, Khashayar AU - Chen, Pengyu AU - Han, Kevin AU - Wu, Tianfu AU - Lobaton, Edgar T2 - Data AB - An autonomous robot that can monitor a construction site should be able to be can contextually detect its surrounding environment by recognizing objects and making decisions based on its observation. Pixel-wise semantic segmentation in real-time is vital to building an autonomous and mobile robot. However, the learning models’ size and high memory usage associated with real-time segmentation are the main challenges for mobile robotics systems that have limited computing resources. To overcome these challenges, this paper presents an efficient semantic segmentation method named LNSNet (lightweight navigable space segmentation network) that can run on embedded platforms to determine navigable space in real-time. The core of model architecture is a new block based on separable convolution which compresses the parameters of present residual block meanwhile maintaining the accuracy and performance. LNSNet is faster, has fewer parameters and less model size, while provides similar accuracy compared to existing models. A new pixel-level annotated dataset for real-time and mobile navigable space segmentation in construction environments has been constructed for the proposed method. The results demonstrate the effectiveness and efficiency that are necessary for the future development of the autonomous robotics systems. DA - 2019/3// PY - 2019/3// DO - 10.3390/data4010040 UR - https://www.mdpi.com/2306-5729/4/1/40 KW - efficient real-time segmentation KW - embedded platform KW - autonomous navigation in construction KW - autonomous data collection ER - TY - JOUR TI - Solid Waste Management Policy Implications on Waste Process Choices and Systemwide Cost and Greenhouse Gas Performance AU - Jaunich, Megan K. AU - Levis, James W. AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. AU - Ranjithan, S. Ranji T2 - Environmental Science & Technology AB - Solid waste management (SWM) is a key function of local government and is critical to protecting human health and the environment. Development of effective SWM strategies should consider comprehensive SWM process choices and policy implications on system-level cost and environmental performance. This analysis evaluated cost and select environmental implications of SWM policies for Wake County, North Carolina using a life-cycle approach. A county-specific data set and scenarios were developed to evaluate alternatives for residential municipal SWM, which included combinations of a mixed waste material recovery facility (MRF), anaerobic digestion, and waste-to-energy combustion in addition to existing SWM infrastructure (composting, landfilling, single stream recycling). Multiple landfill diversion and budget levels were considered for each scenario. At maximum diversion, the greenhouse gas (GHG) mitigation costs ranged from 30 to 900 $/MTCO2e; the lower values were when a mixed waste MRF was used, and the higher values when anaerobic digestion was used. Utilization of the mixed waste MRF was sensitive to the efficiency of material separation and operating cost. Maintaining the current separate collection scheme limited the potential for cost and GHG reductions. Municipalities seeking to cost-effectively increase landfill diversion while reducing GHGs should consider waste-to-energy, mixed waste separation, and changes to collection. DA - 2019/1/11/ PY - 2019/1/11/ DO - 10.1021/acs.est.8b04589 VL - 53 IS - 4 SP - 1766-1775 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.8b04589 DB - Crossref ER - TY - JOUR TI - Temperature- and Humidity-Dependent Phase States of Secondary Organic Aerosols AU - Petters, Sarah S. AU - Kreidenweis, Sonia M. AU - Grieshop, Andrew P. AU - Ziemann, Paul J. AU - Petters, Markus D. T2 - GEOPHYSICAL RESEARCH LETTERS AB - Abstract Viscosity of monoterpene‐derived secondary organic aerosols (SOAs) as a function of temperature and relative humidity (RH), and dry SOA glass transition temperatures are reported. Viscosity was measured using coalescence time scales of synthesized 100 nm dimers. Dry temperature‐dependent SOA viscosity was similar to that of citric acid, coal tar pitch, and sorbitol. The temperature where dry viscosity was 10 6 Pa·s varied between 14 and 36 °C and extrapolated glass transition varied between −10 and 20 °C (±10 °C). Mass fragment f 44 obtained with an Aerosol Chemical Speciation Monitor was anticorrelated with viscosity. Viscosity of humidified Δ 3 ‐carene and α‐pinene SOAs exceeded 10 6 Pa·s for all subsaturated RHs at temperatures <0 and –5 °C, respectively. Steep viscosity isopleths at 10 6 Pa·s were traced for these across (temperature, RH) conditions ranging from (approximately −5 °C, 100%) and (approximately 36 °C, 0%). Differences in composition and thus hygroscopicity can shift humidified viscosity isopleths for SOAs at cold tropospheric temperatures. DA - 2019/1/28/ PY - 2019/1/28/ DO - 10.1029/2018GL080563 VL - 46 IS - 2 SP - 1005-1013 SN - 1944-8007 UR - https://doi.org/10.1029/2018GL080563 ER - TY - JOUR TI - Fostering Safety Communication among Construction Workers: Role of Safety Climate and Crew-Level Cohesion AU - Pandit, Bhavana AU - Albert, Alex AU - Patil, Yashwardhan AU - Al-Bayati, Ahmed Jalil T2 - INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH AB - Safety communication among construction workers is fundamental to effective safety management. However, evidence suggests that poor safety communication is a common problem in construction workplaces. In fact, previous research has unveiled a number of systemic barriers to effective safety communication in the construction industry. When workers do not sufficiently communicate relevant safety hazards and appropriate injury prevention measures, unexpected injuries can follow. Therefore, research examining factors that promote or impede effective safety communication is necessary. Towards achieving this goal, the purpose of the current research was to evaluate the effect of safety climate and crew cohesion on the demonstrated safety communication levels. The goal was achieved by gathering empirical data from 57 construction workplaces in the United States. More specifically, the participating construction workplaces were visited, and data pertaining to the safety climate and crew-level cohesion were first collected using questionnaire surveys. Next, a safety communication survey instrument was administered, and the data necessary to compute network density-a social network metric that is indicative of safety communication levels was gathered. The analysis of the data suggested that a positive relationship exists between safety climate and safety communication levels. Likewise, construction crews that demonstrated higher levels of cohesion exhibited superior safety communication levels. Finally, evidence also suggested that a synergetic effect exists between safety climate and crew cohesion in improving safety communication levels. DA - 2019/1/1/ PY - 2019/1/1/ DO - 10.3390/ijerph16010071 VL - 16 IS - 1 SP - SN - 1660-4601 KW - construction safety KW - safety communication KW - cohesion KW - safety climate KW - occupational safety KW - health and safety ER - TY - JOUR TI - Transportation resilience to climate change and extreme weather events – Beyond risk and robustness AU - Markolf, Samuel A. AU - Hoehne, Christopher AU - Fraser, Andrew AU - Chester, Mikhail V. AU - Underwood, B. Shane T2 - Transport Policy AB - The long-term reliability and functioning of transportation systems will increasingly need to consider and plan for climate change and extreme weather events. Transportation systems have largely been designed and operated for historical climate conditions that are now often exceeded. Emerging knowledge of how to plan for climate change largely embraces risk-based thinking favoring more robust infrastructure designs. However, there remain questions about whether this approach is sufficient given the uncertainty and non-stationarity of the climate, and many other driving factors affecting transportation systems (e.g., funding, rapid technological change, population and utilization shifts, etc.). This paper examines existing research and knowledge related to the vulnerability of the transportation system to climate change and extreme weather events and finds that there are both direct and indirect “pathways of disruption.” Direct pathways of disruption consist of both abrupt impacts to physical infrastructure and impacts via non-physical factors such as human health, behavior, and decision making. Similarly, indirect pathways of disruption result from interconnections with other critical infrastructure and social systems. Currently, the direct pathways appear to receive much of the focus in vulnerability and risk assessments, and the predominant approach for addressing these pathways of disruption emphasizes strengthening and armoring infrastructure (robustness) guided by risk analysis. However, our analysis reveals that indirect pathways of disruption can have meaningful impacts, while also being less amenable to robustness-based approaches. As a result, we posit that concepts like flexibility and agility appear to be well suited to complement the status quo of robustness by addressing the indirect and non-physical pathways of disruption that often prove challenging - thereby improving the resilience of transportation systems. DA - 2019/2// PY - 2019/2// DO - 10.1016/j.tranpol.2018.11.003 VL - 74 SP - 174-186 J2 - Transport Policy LA - en OP - SN - 0967-070X UR - http://dx.doi.org/10.1016/j.tranpol.2018.11.003 DB - Crossref KW - Resilience KW - Robustness KW - Climate change KW - Extreme weather events KW - Agility KW - Flexibility KW - Interconnected infrastructure systems ER - TY - JOUR TI - Advancing Risk-Informed Decision Making in Managing Defense Nuclear Waste in the United States: Opportunities and Challenges for Risk Analysis AU - Greenberg, Michael R. AU - Apostolakis, George AU - Fields, Timothy AU - Goldstein, Bernard D. AU - Kosson, David AU - Krahn, Steven AU - Matthews, R. Bruce AU - Rispoli, James AU - Stewart, Jane AU - Stewart, Richard T2 - RISK ANALYSIS AB - Abstract An omnibus spending bill in 2014 directed the Department of Energy to analyze how effectively Department of Energy (DOE) identifies, programs, and executes its plans to address public health and safety risks that remain as part of DOE's remaining environmental cleanup liabilities. A committee identified two dozen issues and associated recommendations for the DOE, other federal agencies, and the U.S. Congress to consider, as well as other stakeholders such as states and tribal nations. In regard to risk assessment, the committee described a risk review process that uses available data, expert experience, identifies major data gaps, permits input from key stakeholders, and creates an ordered set of risks based on what is known. Probabilistic risk assessments could be a follow‐up from these risk reviews. In regard to risk management, the states, in particular, have become major drivers of how resources are driven. States use different laws, different priorities, and challenge DOE's policies in different ways. Land use decisions vary, technology choices are different, and other notable variations are apparent. The cost differences associated with these differences are marked. The net result is that resources do not necessarily go to the most prominent human health and safety risks, as seen from the national level. DA - 2019/2// PY - 2019/2// DO - 10.1111/risa.13135 VL - 39 IS - 2 SP - 375-388 SN - 1539-6924 KW - DOE KW - risk assessment KW - risk management ER - TY - JOUR TI - Hypoxic volume is more responsive than hypoxic area to nutrient load reductions in the northern Gulf of Mexico-and it matters to fish and fisheries AU - Scavia, Donald AU - Justic, Dubravko AU - Obenour, Daniel R. AU - Craig, J. Kevin AU - Wang, Lixia T2 - ENVIRONMENTAL RESEARCH LETTERS DA - 2019/2// PY - 2019/2// DO - 10.1088/1748-9326/aaf938 VL - 14 IS - 2 SP - SN - 1748-9326 KW - hypoxic volume KW - Gulf of Mexico KW - models KW - nitrogen ER - TY - JOUR TI - Intermediate temperature fracture resistance evaluation of cement emulsified asphalt mortar AU - Jahanbakhsh, Hamid AU - Hosseini, Payam AU - Moghadas Nejad, Fereidoon AU - Habibi, Mehran T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Cement emulsified asphalt mortar (CEAM) as part of the slab track system is subjected to various combinations of repeated train loading and varying environmental conditions leading to fatigue cracking. In this respect, this research examined the fatigue cracking resistance behavior of CEAM through various testing methods applying fracture mechanics. Experimental tests conducted (i.e. indirect tensile (IDT) strength and semicircular bending (SCB)) showed that the fracture parameters (i.e. displacement at fracture, fracture energy, and critical strain energy release rate) could properly evaluate the fatigue performance of CEAM and distinguish additives’ impact at intermediate temperature. Furthermore, correlation analysis was employed to investigate the effect of test-related factors (e.g. specimen size, specimen thickness, notch length, and loading rate) on the assessed fracture parameters and specifying the most suitable parameter for fatigue cracking resistance evaluation of CEAM. According to the results, although the displacement at fracture and fracture energy were capable to assess the fatigue cracking behavior of CEAM, they exhibited to be specimen size dependent. Additionally, results of experiments conducted on CEAM specimens possessing various sizes and geometries along with the correlation analysis indicated that the critical strain energy release rate (Jc) is a potentially feasible parameter to recognize the fatigue cracking resistance of CEAM as a material parameter as it is independent of specimen size and geometry. DA - 2019/2/10/ PY - 2019/2/10/ DO - 10.1016/j.conbuildmat.2018.11.170 VL - 197 SP - 1-11 SN - 1879-0526 KW - Cement emulsified asphalt mortar (CEAM) KW - Fatigue cracking KW - Indirect tensile (IDT) strength KW - Semicircular bending (SCB) test KW - Specimen size ER - TY - JOUR TI - Measuring the Shape and Size of Activated Sludge Particles Immobilized in Agar with an Open Source Software Pipeline AU - Weaver, Joseph E. AU - Williams, Jon C. AU - Ducoste, Joel J. AU - de los Reyes, Francis L., III T2 - Journal of Visualized Experiments AB - Experimental bioreactors, such as those treating wastewater, contain particles whose size and shape are important parameters. For example, the size and shape of activated sludge flocs can indicate the conditions at the microscale, and also directly affect how well the sludge settles in a clarifier. Particle size and shape are both misleadingly 'simple' measurements. Many subtle issues, often unaddressed in informal protocols, can arise when sampling, imaging, and analyzing particles. Sampling methods may be biased or not provide enough statistical power. The samples themselves may be poorly preserved or undergo alteration during immobilization. Images may not be of sufficient quality; overlapping particles, depth of field, magnification level, and various noise can all produce poor results. Poorly specified analysis can introduce bias, such as that produced by manual image thresholding and segmentation. Affordability and throughput are desirable alongside reproducibility. An affordable, high throughput method can enable more frequent particle measurement, producing many images containing thousands of particles. A method that uses inexpensive reagents, a common dissecting microscope, and freely-available open source analysis software allows repeatable, accessible, reproducible, and partially-automated experimental results. Further, the product of such a method can be well-formatted, well-defined, and easily understood by data analysis software, easing both within-lab analyses and data sharing between labs. We present a protocol that details the steps needed to produce such a product, including: sampling, sample preparation and immobilization in agar, digital image acquisition, digital image analysis, and examples of experiment-specific figure generation from the analysis results. We have also included an open-source data analysis pipeline to support this protocol. DA - 2019/1/30/ PY - 2019/1/30/ DO - 10.3791/58963 VL - 2019 IS - 143 SP - J2 - JoVE LA - en OP - SN - 1940-087X UR - http://dx.doi.org/10.3791/58963 DB - Crossref KW - Environmental Sciences KW - Issue 143 KW - Digital image analysis KW - particle size KW - particle shpe KW - activated sludge KW - granular sludge KW - floc KW - morphology KW - microscopy KW - software KW - FIJI ER - TY - JOUR TI - Agent-based modelling approach to evaluate the effect of collaboration among scientists in scientific workflows AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman T2 - JOURNAL OF SIMULATION AB - Automation in science is increasingly marked by the use of workflow systems (eg, Matlab) to facilitate the scientific discovery. The sharing of workflows through publication mechanisms supports the reproducibility and extensibility of computational experiments. However, the subsequent scientific discovery from a workflow relates to the level of collaboration among scientists. An agent-based model (ABM) is developed by coupling a scientific workflow with a model of scientist agents. The scientist agents are able to collaborate using a simplified small-world network. After a query is submitted to scientist agents, each scientist agent is able to extract data from data-sets, which are widely available online, using automated workflows to prepare a scientific report for a query. After data are collected from a workflow, data can be shared among scientists using one of the four collaboration scenarios, which simulate alternative level of data availability. Each scientist uses the data, which is collected from the database or through a shared environment, to deduce a scientific discovery. The ABM is demonstrated and evaluated for application within ecological science. Scientist agents collaborate and use the workflow tool, Kepler, to develop a linear regression model that captures the relationship between zooplankton populations and codfish population in the Norwegian Sea. DA - 2019/1/2/ PY - 2019/1/2/ DO - 10.1080/17477778.2017.1387333 VL - 13 IS - 1 SP - 1-13 SN - 1747-7786 KW - Scientific workflow KW - collaboration KW - agent-based modelling ER - TY - JOUR TI - Stochastic cost-optimization and risk assessment of in situ chemical oxidation for dense non-aqueous phase liquid (DNAPL) source remediation AU - Kim, Ungtae AU - Parker, Jack C. AU - Borden, Robert C. T2 - STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT AB - This study involved development of a computer program to determine optimal design variables for in situ chemical oxidation (ISCO) of dense nonaqueous phase liquid (DNAPL) sites to meet site-wide remediation objectives with minimum life-cycle remediation cost while taking uncertainty in site characterization data and model predictions into consideration. A physically-based ISCO performance model computes field-scale DNAPL dissolution, instantaneous reaction of oxidant with contaminant and with readily oxidizable natural oxidant demand (NOD), second-order kinetic reactions for slowly oxidizable NOD, and time to reach ISCO termination criteria. Remediation cost is computed by coupling the performance model with a cost module. ISCO termination protocols are implemented that allow different treatment subregions (e.g., zones with different estimated contaminant concentrations) to be terminated independently based on statistical criteria related to confidence limits of contaminant concentrations estimated from soil and/or groundwater sampling data. The ISCO model was implemented in the program called Stochastic Cost Optimization Toolkit, which includes modules for additional remediation technologies that can be implemented serially or in parallel coupled with a dissolved plume model to enable design optimization to meet plume-scale cleanup objectives. This study focuses on optimization of ISCO design to meet specified source zone remediation objectives. ISCO design parameters considered for optimization include oxidant concentration and injection rate, frequency and number of soil or groundwater samples, and cleanup criteria for termination of subregion injection. Sensitivity studies and example applications are presented to demonstrate the benefits of proposed stochastic optimization methodology. DA - 2019/1// PY - 2019/1// DO - 10.1007/s00477-018-1633-y VL - 33 IS - 1 SP - 73-89 SN - 1436-3259 KW - Stochastic optimization KW - In situ chemical oxidation KW - Risk assessment KW - DNAPL source remediation KW - Uncertainty analysis ER - TY - JOUR TI - Current state of in-cabinet response spectra for seismic qualification of equipment in nuclear power plants AU - Gupta, Abhinav AU - Cho, Sung-Gook AU - Hong, Kee-Jeung AU - Han, Minsoo T2 - NUCLEAR ENGINEERING AND DESIGN AB - Many nuclear power plants in the south eastern region of South Korea are undertaking seismic qualification studies due to the recent earthquake in Gyeongju region. The records from this earthquake contain high frequency content compared to the frequency exhibited in most of the design basis Safe Shutdown Earthquakes used in the design of nuclear power plants. While the high frequency ground motions are not detrimental to the structures due to relatively smaller displacements, such motions can lead to functionality related failures in electrical equipment and systems such as control relays. The seismic qualification of relays and other such instruments require characterization of in-cabinet response spectra (ICRS) in the cabinet or control panels where they are mounted. The current practice of generating ICRS, in many cases, uses constant amplification factors which are based on studies containing low frequency ground motions. Cabinets can often have higher frequency modes which can amplify the motion if it contains high frequency pulses. Finite element analysis to evaluate the dynamic characteristics of cabinet is highly impractical because each cabinet is vastly different from other cabinets and a given plant contains hundreds of such cabinets and control panels. Therefore, a method is needed to evaluate accurate dynamic characteristics of cabinets and control panels in a relatively simple manner. This paper presents the details of such a method called Ritz vector approach and also compares the ICRS of an actual cabinet for a high frequency input motion with that for a low frequency input motion. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.nucengdes.2018.12.017 VL - 343 SP - 269-275 SN - 1872-759X ER - TY - JOUR TI - Impact of safety climate on hazard recognition and safety risk perception AU - Pandit, Bhavana AU - Albert, Alex AU - Patil, Yashwardhan AU - Al-Bayati, Ahmed Jalil T2 - SAFETY SCIENCE AB - Poor hazard recognition and the underestimation of safety risk can lead to catastrophic safety incidents. Unfortunately, past research has demonstrated that a large number of safety hazards remain unrecognized in construction workplaces. Likewise, evidence also suggests that the underestimation of safety risk is a widespread issue in the construction industry. Therefore, to improve safety performance, a proper understanding of workplace factors that affect hazard recognition and safety risk perception is fundamental. To begin achieving this goal, the current study evaluated the effect of safety climate – a validated leading indicator of safety performance – on hazard recognition and safety risk perception levels. This was accomplished by gathering empirical data from over 280 workers employed in 57 construction workplaces in the United States. More specifically, after gathering safety climate data from the participating workers, the workers were engaged in a hazard recognition and safety risk perception activity. The study findings revealed that workers representing workplaces with a more positive safety climate demonstrate higher levels of hazard recognition and safety risk perception. In addition, the effect of safety climate on safety risk perception was mediated by hazard recognition performance. In other words, safety climate affected hazard recognition performance, which in turn affected safety risk perception levels. Apart from the indirect effect of safety climate on safety risk perception through hazard recognition performance, safety climate also affected safety risk perception independently of hazard recognition performance. The findings of the study will be useful to practicing professionals seeking to improve safety performance in the construction industry. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.ssci.2018.11.020 VL - 113 SP - 44-53 SN - 1879-1042 KW - Construction safety KW - Safety climate KW - Safety management KW - Hazard identification KW - Hazard recognition KW - Risk assessment KW - Risk perception ER - TY - JOUR TI - Indoor Exposure to Ambient Particles and Its Estimation Using Fixed Site Monitors AU - Che, Wenwei AU - Frey, H. Christopher AU - Li, Zhiyuan AU - Lao, Xiangqian AU - Lau, Alexis K. H. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Ambient PM2.5 concentrations measured at fixed site monitors (FSM) are often biased with respect to exposure concentrations because of spatial variability and infiltration. Based on comparison of ambient concentrations from 14 FSMs and of exposure concentrations measured indoors and outdoors at two schools in Hong Kong for winter and summer seasons, the magnitude and sources of exposure error based on using FSMs as a surrogate for exposure are quantified. An approach for bias correcting surrogate exposure estimates from FSMs is demonstrated. The approach is based on a proximity factor (PF) that accounts for differences in spatial locations, proximity to emissions and deviation from dominant wind direction, and an infiltration factor (IF) that varies by season. The combination of the PF and IF reduce bias in mean school exposure estimates from ±90% to ±20%. Bias in exposure estimates from using FSMs as surrogates tend to be smaller for which the exposure site and FSM are aligned with wind direction, have similar sampling height, and are in close proximity. The methodology demonstrated to assess concordance between FSMs and exposure measurement sites can be applied more broadly to help reduce exposure error, which may help to interpret seasonal variations in health estimates. DA - 2019/1/15/ PY - 2019/1/15/ DO - 10.1021/acs.est.8b04474 VL - 53 IS - 2 SP - 808-819 SN - 1520-5851 UR - https://doi.org/10.1021/acs.est.8b04474 ER - TY - JOUR TI - Quantifying the Urban Food-Energy-Water Nexus: The Case of the Detroit Metropolitan Area AU - Liang, Sai AU - Qu, Shen AU - Zhao, Qiaoting AU - Zhang, Xilin AU - Daigger, Glen T. AU - Newell, Joshua P. AU - Miller, Shelie A. AU - Johnson, Jeremiah X. AU - Love, Nancy G. AU - Zhang, Lixiao AU - Yang, Zhifeng AU - Xu, Ming T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - The efficient provision of food, energy, and water (FEW) resources to cities is challenging around the world. Because of the complex interdependence of urban FEW systems, changing components of one system may lead to ripple effects on other systems. However, the inputs, intersectoral flows, stocks, and outputs of these FEW resources from the perspective of an integrated urban FEW system have not been synthetically characterized. Therefore, a standardized and specific accounting method to describe this system is needed to sustainably manage these FEW resources. Using the Detroit Metropolitan Area (DMA) as a case, this study developed such an accounting method by using material and energy flow analysis to quantify this urban FEW nexus. Our results help identify key processes for improving FEW resource efficiencies of the DMA. These include (1) optimizing the dietary habits of households to improve phosphorus use efficiency, (2) improving effluent-disposal standards for nitrogen removal to reduce nitrogen emission levels, (3) promoting adequate fertilization, and (4) enhancing the maintenance of wastewater collection pipelines. With respect to water use, better efficiency of thermoelectric power plants can help reduce water withdrawals. The method used in this study lays the ground for future urban FEW analyses and modeling. DA - 2019/1/15/ PY - 2019/1/15/ DO - 10.1021/acs.est.8b06240 VL - 53 IS - 2 SP - 779-788 SN - 1520-5851 ER - TY - JOUR TI - Social network analysis for construction crews AU - Abbsaian-Hosseini, S. Alireza AU - Liu, Min AU - Hsiang, Simon M. T2 - INTERNATIONAL JOURNAL OF CONSTRUCTION MANAGEMENT AB - Construction crews usually have to share the limited working space with each other during construction to perform their tasks, which increases the chance of interference/conflict and productivity lost. Social network analysis (SNA) has been known as a methodology to determine the conditions of social structures by investigating the interdependencies among a set of actors. The impact of jobsite social network on the performance of the crews has not been well documented in previous research. This research proposes an analytical approach by combining SNA and work plan variation analysis to (1) quantify the influence construction crews receive from jobsite social network, and (2) explore the impact of jobsite social network on the crews’ performance particularly on their work plan variation through a case study. The results indicated that there is a positive monotonic association between each of the centrality indices (representing network influence on each crew) and each of the work plan variability indices (representing crew's performance). The more influences a crew receives form the network, the more work plan variation it will have. A better understanding of the existing jobsite interdependencies will help project managers to control it through better planning and leadership, consequently increasing jobsite productivity. DA - 2019/3/4/ PY - 2019/3/4/ DO - 10.1080/15623599.2017.1389642 VL - 19 IS - 2 SP - 113-127 SN - 2331-2327 KW - Social network analysis KW - construction crews KW - centrality KW - variations KW - interdependency KW - work plan KW - construction management KW - productivity ER - TY - JOUR TI - A spatial multiple treatment/multiple outcome difference-in-differences model with an application to urban rail infrastructure and gentrification AU - Bardaka, Eleni AU - Delgado, Michael S. AU - Florax, Raymond J. G. M. T2 - TRANSPORTATION RESEARCH PART A-POLICY AND PRACTICE AB - We develop a class of difference-in-differences regression models for the case of multiple transportation interventions that may occur sequentially over time and may generate causal spillover effects within a spatial system. We show how these models can be estimated using tools from spatial econometrics, and further extend the models to a system of seemingly unrelated outcomes such that there may be spatial correlation in the error terms. These models facilitate estimation of direct, indirect, and total average causal effects, as well as individual and cumulative effects of transportation interventions that partially overlap in space. Such estimates can assist policymakers in assessing potentially reinforcing effects originating from multiple transportation interventions located in close proximity. We develop an empirical example of our models to evaluate spatiotemporal socioeconomic impacts of the original and expanded light rail system in Denver, CO. DA - 2019/3// PY - 2019/3// DO - 10.1016/j.tra.2019.01.028 VL - 121 SP - 325-345 SN - 0965-8564 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85060518937&partnerID=MN8TOARS KW - Spatial difference-in-differences KW - Quasi-experiment KW - Sequential treatments KW - Spatial spillover effects KW - Seemingly unrelated regressions KW - Urban rail KW - Gentrification ER - TY - JOUR TI - Comparing the travel behavior of affordable and market-rate housing residents in the transit-rich neighborhoods of Denver, CO AU - Bardaka, E. AU - Hersey, J. T2 - Travel Behaviour and Society AB - Equitable transit-oriented development (ETOD) extends an increasingly accepted model for station-area growth by intentionally co-locating affordable housing and transit nodes in order to reduce low-income households’ aggregate housing and transportation costs. Local, regional and state government agencies have enacted ETOD policies to promote this socially vital land use/transportation nexus. This study focuses on Denver, CO, where numerous market-rate, mixed-income, and income-restricted (i.e., affordable) apartments have been built within a 10-min walk of Regional Transportation District (RTD) rail stations. The objective of this research is to compare the travel behavior of station-area residents living in market-rate and affordable apartment units by analyzing the data collected through a household survey distributed to 21 properties with over 2400 units located within a 10-min walk of a rail station. Results from 312 responses indicate substantial differences in key socioeconomic characteristics of the residents (employment status, age, and vehicle ownership), in transportation mode choice, and frequency of use of public transportation (bus and light rail) for accessing employment, healthcare, and grocery stores between residents of affordable and market-rate apartments. DA - 2019/// PY - 2019/// DO - 10.1016/j.tbs.2019.01.001 VL - 15 SP - 74-87 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85059946243&partnerID=MN8TOARS KW - Affordable housing KW - Equitable transit-oriented development KW - Mode choice KW - Urban rail KW - Household survey ER - TY - JOUR TI - Fragility Evaluation in Building-Piping Systems: Effect of Piping Interaction With Buildings AU - Ryu, Yong Hee AU - Gupta, Abhinav AU - Ju, Bu Seog T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - Many studies assessing the damage from 1971 San Fernando and 1994 North Ridge earthquakes reported that the failure of nonstructural components like piping systems was one of the significant reasons for shutdown of hospitals immediately after the earthquakes. This paper is focused on evaluating seismic fragility of a large-scale piping system in representative high-rise, midrise, and low-rise buildings using nonlinear time history analyses. The emphasis is on evaluating piping's interaction with building and its effect on piping fragility. The building models include the effects of nonlinearity in the performance of beams and columns. In a 20-story building that is detuned with the piping system, critical locations are on the top two floors for the linear frame building model. For the nonlinear building model, critical locations are on the bottom two floors. In an eight-story building that is nearly tuned with the piping system, the critical locations for both the linear frame and nonlinear models are the third and fourth floors. It is observed that building nonlinearity can reduce fragility due to reduction in the tuning between building and piping systems. In a two-story building, the nonlinear building frequencies are closer to the critical piping system frequencies than the linear building frequency; the nonlinear building is more fragile than the linear building for this case. However, it is observed that the linear building models give excessively conservative estimates of fragility than the nonlinear building models. DA - 2019/2// PY - 2019/2// DO - 10.1115/1.4039004 VL - 141 IS - 1 SP - SN - 1528-8978 KW - large-scale piping system KW - piping fragility KW - nonlinearity KW - building-piping interaction ER - TY - JOUR TI - Quantification of the influence of subsurface uncertainties on the performance of rocking foundations during seismic loading AU - Gajan, Sivapalan AU - Kayser, Mohammad T2 - SOIL DYNAMICS AND EARTHQUAKE ENGINEERING AB - The major objective of this paper is to quantify the effects of uncertainties in soil properties and loading conditions on the performance of rocking foundations during seismic loading. Probabilistic numerical simulations were carried out using a validated soil-foundation Contact Interface Model in OpenSees finite element framework. Results indicate that for relatively larger static vertical factor of safety systems, the moment capacity of rocking foundations mainly depends on the applied vertical load on the foundation as opposed to the bearing capacity, while the energy dissipation and settlement are more sensitive to initial vertical stiffness of soil-foundation system and applied vertical load. DA - 2019/1// PY - 2019/1// DO - 10.1016/j.soildyn.2018.09.029 VL - 116 SP - 1-14 SN - 1879-341X KW - Soil-structure interaction KW - Shallow foundations KW - Settlement KW - Earthquake loading KW - Sand KW - Clay ER - TY - JOUR TI - Genetic Algorithm–Genetic Programming Approach to Identify Hierarchical Models for Ultraviolet Disinfection Reactors AU - Monroe, Jacob G. AU - Ducoste, Joel AU - Berglund, Emily Z. T2 - Journal of Environmental Engineering AB - AbstractThe performance of ultraviolet (UV) disinfection reactors using experimental data poses major challenges to the water treatment industry, and a regression model has been developed in the wa... DA - 2019/2// PY - 2019/2// DO - 10.1061/(ASCE)EE.1943-7870.0001492 VL - 145 IS - 2 SP - 04018139 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001492 DB - Crossref KW - System identification KW - Symbolic regression KW - Evolutionary computation KW - Bloat KW - Drinking water treatment ER - TY - JOUR TI - Are Visual Search Patterns Predictive of Hazard Recognition Performance? Empirical Investigation Using Eye-Tracking Technology AU - Jeelani, Idris AU - Albert, Alex AU - Han, Kevin AU - Azevedo, Roger T2 - Journal of Construction Engineering and Management AB - Poor hazard recognition is a widespread issue in the construction industry. When construction hazards remain unrecognized, workers are more likely to indulge in unsafe behavior, experience unanticipated hazard exposure, and suffer catastrophic injuries. To improve our understanding of why construction hazards remain unrecognized, the current study examined hazard recognition as an everyday visual search task—similar to an individual searching for a product in a supermarket, a radiologist examining a radiograph for tissue abnormalities, or a security personnel screening baggage at an airport terminal. More specifically, the research used eye-tracking technology to examine the relationship between visual search patterns adopted by workers while participating in a hazard recognition activity and the resulting performance levels (i.e., hazard recognition performance). The research also focused on testing the effects of introducing a recently developed personalized training intervention on visual search patterns adopted by workers—and the subsequent hazard recognition performance. Visual search patterns examined in the study included search duration, fixation count, fixation spatial density, and others identified from past research. The results reveal that several quantifiable visual search patterns are predictive of superior hazard recognition performance. For example, workers who spent more time examining the workplace for safety hazards (i.e., search duration) recognized a larger proportion of hazards. Likewise, workers that devoted higher levels of attention through a larger number of fixations (i.e., fixation count) and longer fixation durations (i.e., fixation time), and those that distributed their visual attention more broadly across the work area (i.e., fixation spatial density), demonstrated superior performance. The findings also suggest that the adoption of the personalized intervention can lead to improvements in visual search patterns and hazard recognition performance among workers. The present research will be useful to diagnose and remedy search weaknesses demonstrated by workers (i.e., human factors) that are associated with poor hazard recognition levels. DA - 2019/1// PY - 2019/1// DO - 10.1061/(ASCE)CO.1943-7862.0001589 VL - 145 IS - 1 SP - 04018115 J2 - J. Constr. Eng. Manage. LA - en OP - SN - 0733-9364 1943-7862 UR - http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0001589 DB - Crossref KW - Construction safety KW - Hazard recognition KW - Hazard identification KW - Eye-tracking KW - Visual search KW - Safety training KW - Personalized training KW - Occupational safety KW - Human factors ER - TY - JOUR TI - Dissolved organicmatter processing and photoreactivity in a wastewater treatment constructed wetland AU - Sardana, Arpit AU - Cottrell, Barbara AU - Soulsby, David AU - Aziz, Tarek N. T2 - SCIENCE OF THE TOTAL ENVIRONMENT AB - Constructed wetlands have the capacity to degrade a host of contaminants of emerging concern through photodegradation via sunlight produced reactive oxygen species. Dissolved organic matter (DOM) is a critical intermediary in photodegradation as it influences the production of reactive oxygen species. In this study, the photochemical behavior of DOM of wastewater treated in constructed wetlands was characterized. Whole water samples and fractionated DOM were characterized using SUVA254, spectral slope ratios, excitation emission matrix fluorescence spectroscopy (EEMs), and proton nuclear magnetic resonance (1H NMR). Photoreactivity was assessed by measuring formation rates and steady state concentrations of hydroxyl radical (•OH), singlet oxygen (1O2), and the triplet excited states of DOM (3DOM⁎). The effluent was observed to transition from a microbially sourced protein-like DOM to a terrestrial DOM with higher aromaticity. Size exclusion chromatography revealed an 18% increase in larger molecular weight fractions of vegetated wetland effluent DOM. Additionally, wetland effluent DOM was observed to have a 32% increase in the aromatic region of 1H NMR spectra as compared to untreated wastewater. 1H NMR analysis also indicated an increase in the complexity of wetland effluent DOM. Fluorescence intensity fraction of the protein-like Peak T (Ex/Em:278/342 nm) of EEMs decreased by 16% from the untreated wastewater to wetland effluent. A negative correlation between the percent fluorescence of Peak T (Ex/Em:278/342 nm) and Peaks A (Ex/Em:245/460 nm), C (Ex/Em:336/435 nm), and M (Ex/Em:312/400 nm) of the excitation emission spectra confirmed the transition from a spectrum of pure wastewater to a spectrum characteristic of terrestrially derived DOM. Microbial uptake of bio-labile DOM and leaching of humic like substances from vegetated wetland cells were the predominant processes involved in this transition. This transition coincided with an increase in the formation rates of 1O2 and 3DOM⁎ and in the steady state concentration of 1O2. DA - 2019/1/15/ PY - 2019/1/15/ DO - 10.1016/j.scitotenv.2018.08.138 VL - 648 SP - 923-934 SN - 1879-1026 UR - http://dx.doi.org/10.1016/j.scitotenv.2018.08.138 KW - Constructed wetlands KW - Dissolved organic matter KW - Photochemistry ER -