TY - CONF TI - Geographic and seasonal variations in air exchange rate and their impacts on the estimation of children's exposure to ambient PM2.5 AU - Che, W. AU - Frey, H.C. AU - Lau, A.K.H. AU - Fung, J.C.H. C2 - 2014/// C3 - Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate DA - 2014/// SP - 836-839 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84924657052&partnerID=MN8TOARS ER - TY - CONF TI - Comparison of real-world emission rates of a locomotive engine operating on diesel and biodiesel AU - Graver, B.M. AU - Hu, J. AU - Frey, H.C. C2 - 2014/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2014/// VL - 2 SP - 991-999 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84939813222&partnerID=MN8TOARS ER - TY - JOUR TI - Spatial and Temporal Variation in De Facto Wastewater Reuse in Drinking Water Systems across the U.S.A. AU - Rice, Jacelyn AU - Westerhoff, Paul T2 - Environmental Science & Technology AB - De facto potable reuse occurs when treated wastewater is discharged into surface waters upstream of potable drinking water treatment plant (DWTP) intakes. Wastewater treatment plant (WWTP) discharges may pose water quality risks at the downstream DWTP, but additional flow aids in providing a reliable water supply source. In this work de facto reuse is analyzed for 2056 surface water intakes serving 1210 DWTPs across the U.S.A. that serve greater than 10 000 people, covering approximately 82% of the nation’s population. An ArcGIS model is developed to assess spatial relationships between DWTPs and WWTPs, with a python script designed to perform a network analysis by hydrologic region. A high frequency of de facto reuse occurrence was observed; 50% of the DWTP intakes are potentially impacted by upstream WWTP discharges. However, the magnitude of de facto reuse was seen to be relatively low, where 50% of the impacted intakes contained less than 1% treated municipal wastewater under average streamflow conditions. De facto reuse increased greatly under low streamflow conditions (modeled by Q95), with 32 of the 80 sites yielding at least 50% treated wastewater, this portion of the analysis is limited to sites where stream gauge data was readily available. DA - 2014/// PY - 2014/// DO - 10.1021/es5048057 VL - 49 IS - 2 SP - 982-989 ER - TY - CONF TI - Characterization of Structural Response of Two OCAES Vessel Configurations under Operational Loading AU - Xiao, Jinfu AU - Gabr, M.A. AU - Rahman, M.S. T2 - 5th International Conference on Ocean Energy (ICOE) C2 - 2014/11// C3 - 5th International Conference on Ocean Energy (ICOE) CY - Halifax, Nova Scotia DA - 2014/11// PY - 2014/11// ER - TY - CONF TI - Effects of wind penetration in the scheduling of a hydro-dominant power system AU - Silva, S.R. AU - De Queiroz, A.R. AU - Lima, L.M.M. AU - Lima, J.W.M. AB - A computational model that is able to determine the optimal economic generation scheduling considering decisions in a system with hydro, thermal and wind power plants is presented. The algorithm is based on the class of sampling-based decomposition algorithms used to solve large-scale multi-stage stochastic optimization problems. A case study composed by several simulation runs of the model is presented and the results about wind power effects in the scheduling of power generators are discussed. C2 - 2014/// C3 - IEEE Power and Energy Society General Meeting DA - 2014/// DO - 10.1109/PESGM.2014.6939121 VL - 2014-October M1 - October UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84930995311&partnerID=MN8TOARS ER - TY - JOUR TI - Phytoremediation of levonorgestrel in aquatic environment by hydrophytes AU - Li, G. AU - Zhai, J. AU - He, Q. AU - Zhi, Y. AU - Xiao, H. AU - Rong, J. T2 - Journal of Environmental Sciences (China) AB - Adsorption and degradation of levonorgestrel (LNG) by two hydrophytes, Cyperus alternifolius (CA) and Eichhornia crassipes (EC), were investigated under light-shielding conditions in the water column. Variations of LNG concentrations in water, plant root epidermis, root, stem and leaf of the plants were analyzed. The results indicated that the removal efficiency of LNG by hydrophytes over the period of 50 days was significantly greater than the blank control (p < 0.05), with the removal rates of 79.80% ± 3.10% and 78.86% ± 2.55% for CA and EC, respectively. Compared with bio-adsorption, bio-conversion of LNG was found to be the dominant elimination pathway, evidenced by relatively high conversion rates (77.31% ± 2.68% for CA and 77.82% ± 2.95% for EC), while the adsorption rates were lower (1.77% ± 0.90% for CA and 1.05% ± 0.40% for EC). The bio-adsorption and conversion of LNG showed no significant differences between the two hydrophytes. Additionally, the mineralization on root epidermis played an important role in the reduction of LNG in water. DA - 2014/// PY - 2014/// DO - 10.1016/j.jes.2014.06.030 VL - 26 IS - 9 SP - 1869-1873 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84906942147&partnerID=MN8TOARS KW - Phytoremediation KW - Hydrophyte KW - Levonorgestrel KW - Hormone KW - Degradation ER - TY - SOUND TI - Data and CFD to Compare Horizontal and Vertical/enclosed UV Reactors AU - Ducoste, J.J. DA - 2014/// PY - 2014/// ER - TY - SOUND TI - Evaluation of Alternative Herbicides for Root Control: Should we be worried about their impact on Wastewater Treatment Plants? AU - Ducoste, J.J. DA - 2014/// PY - 2014/// ER - TY - CONF TI - CFD as a tool for WWTP Unit Process Modeling AU - Samstag, R. AU - Ducoste, J. AU - Gribrio, A. AU - Nopens, I. AU - Batstone, D. AU - Wicks, J. AU - Saunders, S. AU - Laurent, J. AU - Potier, O. T2 - International Water Association (IWA)/Water Environment Federation (WEF) Waste Water Treatment (WWT) MOD C2 - 2014/3/30/ CY - Belgium DA - 2014/3/30/ PY - 2014/3/30/ ER - TY - CONF TI - PBMs: A Modeling Framework for WWTP Modeling AU - Nopens, I. AU - Torfs, E. AU - Ducoste, J. AU - Vanrolleghem, P. AU - Gernaey, K. T2 - International Water Association (IWA)/Water Environment Federation (WEF) Waste Water Treatment (WWT) MOD C2 - 2014/3/30/ CY - Belgium DA - 2014/3/30/ PY - 2014/3/30/ ER - TY - CONF TI - Pulse Feeding Of Anaerobic Digesters Treating Grease Waste To Increase Community Resistance AU - Wang, L. AU - Hossen, E.H. AU - Aziz, T.N. AU - Ducoste, J. AU - Bullard, M. AU - de los Reyes, F.L. T2 - International Water Association (IWA) World Water Congress & Exhibition C2 - 2014/9/21/ CY - Lisbon, Portugal DA - 2014/9/21/ PY - 2014/9/21/ ER - TY - CONF TI - Influencing Aerobic Granulation through Variable Shear in an Eccentric Couette Micro-Reactor AU - Weaver, J. AU - Ducoste, J. AU - de los Reyes, F.L. T2 - North Carolina Section of the American Water Works Association (NC AWWA) Water Environment Association (WEA) Conference C2 - 2014/11/16/ CY - Winston Salem NC DA - 2014/11/16/ PY - 2014/11/16/ ER - TY - CONF TI - Creating Water, Sanitation, and Hygiene (WASH) Program Awareness in Schools: A tool Towards the Success of Community WASH Programs, AU - Olukanni, D.O. AU - Ducoste, J. AU - George, T.O. T2 - 6th International Conference on Education and New Learning Technologies C2 - 2014/7/7/ C3 - EDULEARN14 Proceedings CY - Barcelona Spain DA - 2014/7/7/ PY - 2014/7/7/ SP - 6922-6927 PB - IATED SN - 9788461705573 ER - TY - CONF TI - Using a systems biology approach to identify key transcriptional regulators in the Arabidopsis thaliana iron deficiency response AU - Matthiadis, Anna AU - Koryachko, Alexandr AU - Muhammad, Durreshahwar AU - Ducoste, Joel AU - Tuck, James AU - Williams, Cranos AU - Long, Terri T2 - 9th International BioMetals Symposium C2 - 2014/// CY - Duke University, Durham, NC DA - 2014/// PY - 2014/7// ER - TY - CONF TI - Computational Fluid Dynamics Optimization of a Continuous Flow Point of Use UV LED Disinfection Reactor AU - Jenny, R. AU - Ducoste, J. T2 - International Ultraviolet Association (IUVA) Regional Conference C2 - 2014/// CY - White Plains, NY DA - 2014/// PY - 2014/10/26/ ER - TY - CONF TI - Step and Pulse Feeding Of Anaerobic Co-Digesters Treating Thickened Waste Activated Sludge and Grease Interceptor Waste AU - Wang, L. AU - Hossen, E.H. AU - Aziz, T.N. AU - Ducoste, J. AU - Bullard, M. AU - de los Reyes, F.L. T2 - Water Resources Research Institute Annual Conference C2 - 2014/3/19/ CY - Raleigh, NC DA - 2014/3/19/ PY - 2014/3/19/ ER - TY - CONF TI - Challenges in Designing a UV LED Reactor for Disinfection: Why CFD Should be your Best Friend AU - Jenny, R. AU - Ducoste, J. T2 - American Water Works Association, Water Quality Technology Conference (AWWA WQTC) C2 - 2014/11/16/ CY - New Orleans, LA DA - 2014/11/16/ PY - 2014/11/16/ ER - TY - JOUR TI - Effect of source and environmental factors on properties and kinetics of FOG deposits in sewer collection systems AU - Iasmin, Mahbuba AU - Ducoste, Joel J. T2 - Proceedings of the Water Environment Federation DA - 2014/10/1/ PY - 2014/10/1/ DO - 10.2175/193864714816099266 VL - 2014 IS - 4 SP - 1-11 J2 - proc water environ fed LA - en OP - SN - 1938-6478 UR - http://dx.doi.org/10.2175/193864714816099266 DB - Crossref ER - TY - CONF TI - Methods to Measure the Hydrogen Sulfide Production Potential of Sulfate-Containing Wastes in Landfills-Laboratory Scale Bioreactor AU - Sun, W. AU - Barlaz, M.A. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Measurement of Chemical Leaching Potential of Sulfate from Landfill Disposed Sulfate-Containing Wastes AU - Sun, W. AU - Barlaz, M.A. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Comparison of Methane Emissions Using Different Greenhouse Gas Reporting Protocols and Measured Methane Emissions from a Landfill without Gas Collection System AU - de la Cruz, F.B. AU - Green, R.B. AU - Chanton, J.P. AU - Thoma, E.D. AU - Foster-Wittig, T.A. AU - Barlaz, M.A. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Characterization of Biological Activity in Refuse Samples Excavated from the Waimanalo Gulch Sanitary Landfill AU - Barlaz, M.A. AU - Sadri, A. AU - Luettich, S. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - SOUND TI - A New Life-Cycle Methodology to Estimate the U.S. National Average Landfill Gas Collection Efficiency for Various Landfill Types AU - Barlaz, M.A. DA - 2014/// PY - 2014/// ER - TY - CONF TI - Characterization of Uncertainty in Modeling of Methane Generation from Select U.S. Landfills AU - Wang, X. AU - Nagpure, A.S. AU - DeCarolis, J.F. AU - Barlaz, M.A. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Sustainable Post-Closure Care Paradigm for Municipal Landfills AU - Morris, J.W.F. AU - Espinoza, R.D. AU - Barlaz, M.A. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Perfluoroalkyl and Polyfluoroalkyl Substances in Municipal Waste and Landfill Leachate AU - Lang, J.R. AU - Barlaz, M.A. AU - Allred, B.M. AU - Field, J. T2 - Intercontinental Landfill Research Symposium C2 - 2014/// CY - Crystal River, FL DA - 2014/// PY - 2014/10/19/ ER - TY - CONF TI - Fluorochemical Compounds in Municipal Solid Waste and Landfill Leachate AU - Lang, J.R. AU - Barlaz, M.A. AU - Allred, B.M. AU - Field, J. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Characterization of Uncertainty in Modeling of Methane Generation from Select U.S. Landfills AU - Wang, X. AU - Barlaz, M.A. AU - DeCarolis, J. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Optimal Sustainable Solid Waste Management in Consideration of Changes to Population, Waste Generation and Composition, and the Energy System AU - Levis, J. AU - Barlaz, M.A. AU - DeCarolis, J.F. AU - Ranjithan, R. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Assessing Methods to Estimate Emissions of Non-Methane Organic Compounds from Landfills AU - Saquing, J. AU - Chanton, J.P. AU - Yazdani, R. AU - Barlaz, M.A. AU - Scheutz, C. AU - Blake, D.R. AU - Imhoff, P.T. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Methods to Measure the Hydrogen Sulfide Production Potential or Sulfate-Containing Wastes - Laboratory Scale Bioreactor and Batch Study AU - Sun, W. AU - Barlaz, M.A. AU - Sun, M. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - A New Life-Cycle Methodology to Estimate the U.S. National Average Landfill Gas Collection Efficiency for Various landfill Types AU - Levis, J. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Chemical Changes during Anaerobic Decomposition of Lignocellulose under Mesophilic and Thermophilic Conditions AU - de la Cruz, F. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Comparison of the Life-Cycle Emissions from Commercial Source-Separated Organic Waste Management Alternatives AU - Levis, J. AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - RPRT TI - Evaluation of Available Scale-up Approaches for the Design of GAC Contactors AU - Summers, R.S. AU - Kennedy, A.M. AU - Knappe, D.R.U. AU - Reinert, A.M. AU - Fotta, M.E. AU - Mastropole, A.J. AU - Corwin, C.J. AU - Roccaro, J. A3 - Water Research Foundation DA - 2014/// PY - 2014/// M1 - 4235 M3 - Final report PB - Water Research Foundation SN - 4235 ER - TY - JOUR TI - An evaluation of the Stormwater Footprint Calculator and the Hydrological Footprint Residence for communicating about sustainability in stormwater management AU - Scott, Tommi Jo AU - Politte, Alyssa AU - Saathoff, Sean AU - Collard, Sam AU - Berglund, Emily AU - Barbour, Joshua AU - Sprintson, Alex T2 - Sustainability: Science, Practice and Policy AB - Low-Impact Development (LID) can enhance sustainability in stormwater management by attenuating excess runoff. Relevant technologies are typically implemented at individual lots and require the engagement of homeowners and developers. A new educational tool, the Stormwater Footprint Calculator (SFC), was developed to improve knowledge and change attitudes and behavior regarding stormwater sustainability. Similar to online carbon-footprint calculators, the SFC synthesizes a participant’s answers about lot and neighborhood-level land use and calculates hypothetical effects on instream flows, using hydrologic simulation. Participants receive feedback about their storm-water footprint using a new metric, the Hydrologic Footprint Residence (HFR), which measures the effect of urbanization on stream flow based on the duration and extent of flooding. An experiment was fielded to test the SFC as a tool for communicating about sustainable stormwater management and to compare the HFR against an orthodox stormwater metric, peak flow. A convenience sample of undergraduate students (N= 510) participated in the experiment. The results indicate that completing the SFC improves knowledge about the causes of stormwater runoff and LID technologies (although not about the effects of stormwater, which was already high among the students), and it influences intention to support sustainable stormwater management. The results also indicate that HFR provides a viable alternative to conventional engineering metrics for communicating a stormwater footprint and shows the value of online calculators for communicating complex civil engineering concepts. DA - 2014/10// PY - 2014/10// DO - 10.1080/15487733.2014.11908129 VL - 10 IS - 2 SP - 14-27 J2 - Sustainability: Science, Practice and Policy LA - en OP - SN - 1548-7733 UR - http://dx.doi.org/10.1080/15487733.2014.11908129 DB - Crossref ER - TY - JOUR TI - The Effect of Elevated Temperature on the Bond Between High Modulus Carbon Fibre-Reinforced Polymer Sheet and Steel AU - Liu, H. AU - Zhao, X. AU - Bai, Y. AU - Singh, R. AU - Rizkalla, S. AU - Bandyopadhyay, S. T2 - Australian Journal of Structural Engineering DA - 2014/7// PY - 2014/7// DO - 10.7158/13287982.2014.11465170 VL - 15 IS - 4 SP - 355–366 ER - TY - JOUR TI - Guest Editorial: Coastal Dunes Essential to a Resilient Coast AU - Overton, M. T2 - Shore & Beach DA - 2014/// PY - 2014/// VL - 82 IS - 4 ER - TY - BOOK TI - Challenges and Best Practices of Managing Government Projects and Programs AU - Kwak, Y. AU - Liu, M. AU - Patanakul, P. AU - Zwikael, O. DA - 2014/// PY - 2014/// PB - Project Management Institute Inc SN - 978-1-62825-065-7. ER - TY - JOUR TI - What is the optimal way for a suburban U.S. city to sustainably manage future solid waste? Perspectives from the Solid Waste Optimization Life-cycle Framework (SWOLF) AU - Levis, J.W. AU - Barlaz, M.A. AU - DeCarolis, J.F. AU - Ranjithan, S.Ranji T2 - Environmental Science & Technology DA - 2014/// PY - 2014/// VL - 48 IS - 7 SP - 3625 – 3631 ER - TY - CONF TI - A Life-Cycle Examination of the Global Warming Potential and Cumulative Energy Demand of Municipal Solid Waste Treatment via a Gasification and Fischer-Tropsch Process AU - Pressley, P. AU - Barlaz, M.A. AU - Levis, J. AU - DeCarolis, J. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Environmental Implications of Empirical Solid Waste Collection Data from U.S. Municipalities AU - Jaunich, M. AU - Levis, J. AU - Barlaz, M. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Characterization of Biological Activity in Refuse Samples Excavated from the Waimanalo Gulch Sanitary Landfill AU - Barlaz, M.A. T2 - Global Waste Management Symposium C2 - 2014/// CY - Orlando, FL DA - 2014/// PY - 2014/6/22/ ER - TY - CONF TI - Where to Locate the Elastic Half-Space in Site Response Analysis, A Case Study Using Site Profiles from Charleston, SC, USA AU - Cabas, A. AU - Cárcamo, P. AU - Rodriguez-Marek, A. AU - Godfrey, B. AU - Olgun, G. T2 - Second European Conference on Earthquake Engineering and Seismology C2 - 2014/// CY - Istanbul, Turkey DA - 2014/// PY - 2014/8/25/ ER - TY - RPRT TI - Landfill Gas Monte Carlo Model Documentation and Results. Report to ICF for the U.S AU - Levis, J.W. AU - Barlaz, M.A. DA - 2014/6/18/ PY - 2014/6/18/ UR - https://www.epa.gov/sites/production/files/2016-03/documents/lanfl_gas_mont_carlo_modl.pdf ER - TY - CONF TI - Water and ecological sustainability under near-term climate change AU - Arumugam, S. T2 - Water Sustainability and Climate (WSC) PI meeting C2 - 2014/1/28/ CY - National Institute of Food and Agriculture DA - 2014/1/28/ PY - 2014/1/28/ ER - TY - SOUND TI - Reducing the uncertainty in projecting future streamflow using paleo and instrumental records along with near-term climate change projections AU - Patskoski, J. AU - Arumugam, S. DA - 2014/6/18/ PY - 2014/6/18/ ER - TY - CONF TI - The Utility of CMIP5 Climate Change Projections in Estimating Hydrologic Impacts in the Conterminous US AU - Sinha, T. AU - Arumugam, S. T2 - UCOWR-NIWR-CUAHSI International Conference C2 - 2014/6/18/ CY - Tufts University, Medford, MA DA - 2014/6/18/ PY - 2014/6/18/ ER - TY - CONF TI - Implications of Water Use and Hydroclimatic Anomalies on the Freshwater Sustainability across the US Sunbelt AU - Arumugam, S. T2 - American Geophysical Union Fall Meeting C2 - 2014/12/15/ CY - San Francisco, CA DA - 2014/12/15/ PY - 2014/12/15/ ER - TY - CONF TI - Improved Water and Energy Management Utilizing Seasonal to Interannual Hydroclimatic Forecasts AU - Arumugam, S. AU - Lall, U. T2 - American Geophysical Union Fall Meeting C2 - 2014/12/15/ CY - San Francisco, CA DA - 2014/12/15/ PY - 2014/12/15/ ER - TY - RPRT TI - Meso level discrete element modeling for localized failure in concrete AU - Roy, T. A3 - Indian Institute of Technology DA - 2014/// PY - 2014/// M3 - M.Tech. Thesis PB - Indian Institute of Technology ER - TY - RPRT TI - Sustainable Anaerobic Co-Digestion of Grease Interceptor Waste AU - Aziz, Tarek A3 - Water Resources Research Institute of the University of North Carolina DA - 2014/// PY - 2014/// PB - Water Resources Research Institute of the University of North Carolina ER - TY - JOUR TI - Geotechnical Special Publication AU - Fuentes, Luis G AU - Goenaga, Boris AU - Reyes, Oscar AU - Alvarez, Allex DA - 2014/// PY - 2014/// ER - TY - CHAP TI - Development of pavement performance prediction models for the Colombian Highway Network AU - Fuentes, Luis G AU - Goenaga, Boris AU - Reyes, Oscar AU - Alvarez, Allex T2 - Design, Analysis, and Asphalt Material Characterization for Road and Airfield Pavements PY - 2014/// SP - 155-162 ER - TY - CONF TI - Development of pavement performance prediction models for the Colombian Highway Network AU - Fuentes, L.G. AU - Goenaga, B. AU - Reyes, O. AU - Alvarez, A. AB - A pavement management system (PMS) consists of a set of defined procedures for collecting, analyzing, maintaining, and reporting pavement data to provide an aid tool in the decision-making process. Modeling of pavement performance is essential to pavement management. A transition probability matrix (TPM) can be used to model pavement deterioration with time. In the present investigation, the derivation of transition matrices was based on historic data of the International Roughness Index (IRI). Data used on this investigation was collected on a specific program called Corredores de Mantenimiento integral implemented by the Colombian National Highway Institute (INVIAS) from 2005 to 2009. Results indicate that the IRI was sensitive to short-term effects; therefore, it was possible to establish a model to accurately predict its condition for the available data. C2 - 2014/// C3 - Geotechnical Special Publication DA - 2014/// DO - 10.1061/9780784478462.019 SP - 155-162 M1 - 246 GSP UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84905870467&partnerID=MN8TOARS ER - TY - CONF TI - The Importance of the Elastic Half-Space Assumption in Site Response Analysis AU - Cabas, A. AU - Rodriguez-Marek, A. T2 - Annual Meeting of the Seismological Society of America C2 - 2014/5/2/ C3 - Proceedings of the Annual Meeting of the Seismological Society of America CY - Anchorage, AK DA - 2014/5/2/ PY - 2014/5/2/ ER - TY - CONF TI - Influence of the Selection of Input Motions on the Systematic Errors Introduced in Site Response Analyses Conducted in Charleston, SC AU - Cabas, A. AU - Rodriguez-Marek, A. T2 - 86th Annual Meeting of the Eastern Section of the Seismological Society of America C2 - 2014/11/2/ C3 - Proceedings of the 86th Annual Meeting of the Eastern Section of the Seismological Society of America CY - Charleston, South Carolina DA - 2014/11/2/ PY - 2014/11/2/ ER - TY - JOUR TI - Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis AU - Siegert, Michael AU - Yates, Matthew D. AU - Call, Douglas F. AU - Zhu, Xiuping AU - Spormann, Alfred AU - Logan, Bruce E. T2 - ACS Sustainable Chemistry & Engineering AB - In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At -600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm-3 d-1) and the highest biotic methane production rate (250 ± 90 nmol cm-3 d-1). At -550 mV, plain graphite (76 nmol cm-3 d-1) performed similarly to platinum (73 nmol cm-3 d-1). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production. DA - 2014/2/26/ PY - 2014/2/26/ DO - 10.1021/sc400520x VL - 2 IS - 4 SP - 910-917 J2 - ACS Sustainable Chem. Eng. LA - en OP - SN - 2168-0485 2168-0485 UR - http://dx.doi.org/10.1021/sc400520x DB - Crossref KW - Biocathode KW - Carbon capturing and sequestration KW - Microbial electrolysis cell KW - Power-to-gas KW - Microbially influenced corrosion KW - Carbon black KW - Graphite KW - Polyaciylonitrile ER - TY - JOUR TI - Improving Forecasts for Water Management AU - Arumugam, Sankar AU - Wood, Andy AU - Rajagopalan, Balaji AU - Schaake, John T2 - Eos, Transactions American Geophysical Union AB - Recent advances in seasonal to interannual hydroclimate predictions provide an opportunity for developing a proactive approach toward water management. This motivated a recent AGU Chapman Conference (see program details at http://chapman.agu.org/watermanagement/ ). Approximately 85 participants from the United States, Oceania, Asia, Europe, and South America presented and discussed the current state of successes, challenges, and opportunities in seasonal to interannual hydroclimate forecasts and water management, and a number of key messages emerged. DA - 2014/1/7/ PY - 2014/1/7/ DO - 10.1002/2014EO010004 VL - 95 IS - 1 SP - 3-3 J2 - Eos Trans. AGU LA - en OP - SN - 0096-3941 UR - http://dx.doi.org/10.1002/2014EO010004 DB - Crossref ER - TY - JOUR TI - Climate risk management for water in semi–arid regions AU - Robertson, Andrew W AU - Baethgen, Walter AU - Block, Paul AU - Lall, Upmanu AU - Sankarasubramanian, Arumugam AU - de Assis de Souza Filho, Francisco AU - J Verbist, Koen M T2 - Earth Perspectives AB - New sources of hydroclimate information based on forecast models and observational data have the potential to greatly improve the management of water resources in semi-arid regions prone to drought. Better management of climate-related risks and opportunities requires both new methods to develop forecasts of drought indicators and river flow, as well as better strategies to incorporate these forecasts into drought, river or reservoir management systems. In each case the existing institutional and policy context is key, making a collaborative approach involving stakeholders essential. This paper describes work done at the IRI over the past decade to develop statistical hydrologic forecast and water allocation models for the semi arid regions of NE Brazil (the “Nordeste”) and central northern Chile based on seasonal climate forecasts. In both locations, downscaled precipitation forecasts based on lagged SST predictors or GCM precipitation forecasts exhibit quite high skill. Spring-summer melt flow in Chile is shown to be highly predictable based on estimates of previous winter precipitation, and moderately predictable up to 6 months in advance using climate forecasts. Retrospective streamflow forecasts here are quite effective in predicting reductions in water rights during dry years. For the multi-use Oros reservoir in NE Brazil, streamflow forecasts have the most potential to optimize water allocations during multi-year low-flow periods, while the potential is higher for smaller reservoirs, relative to demand. This work demonstrates the potential value of seasonal climate forecasting as an integral part of drought early warning and for water allocation decision support systems in semi-arid regions. As human demands for water rise over time this potential is certain to rise in the future. DA - 2014/// PY - 2014/// DO - 10.1186/2194-6434-1-12 VL - 1 IS - 1 SP - 12 J2 - Earth Perspectives LA - en OP - SN - 2194-6434 UR - http://dx.doi.org/10.1186/2194-6434-1-12 DB - Crossref ER - TY - CONF TI - Behavior of Bio-Mediated Soil ink0Loading AU - Feng, K. AU - Montoya, B. M. T2 - Geo-Shanghai 2014 AB - Microbial induced carbonate precipitation is a novel soil improvement method that has demonstrated potential to strengthen the ground in a sustainable and eco-friendly manner. Previous investigations have studied its mechanical behavior through conventional triaxial or soil column tests. However, there is limited information about the bio-cemented sand's properties under k0 loading, which more closely resembles some in situ stress conditions. Using a modified consolidation cell with shear wave velocity monitoring via bender elements, the authors investigate the behavior of bio-treated sand under loading and unloading. The effects of cementation degree(shear wave velocity 350 m/s and 700 m/s after cementation) and initial densities(loose and dense) are explored through careful preparation of samples. The results of the bio-cemented specimens under an incremental loading and unloading sequence are compared to that of uncemented sand at similar densities. C2 - 2014/5/5/ C3 - New Frontiers in Geotechnical Engineering DA - 2014/5/5/ DO - 10.1061/9780784413456.001 PB - American Society of Civil Engineers SN - 9780784413456 UR - http://dx.doi.org/10.1061/9780784413456.001 DB - Crossref ER - TY - JOUR TI - Assessment of energy storage for transmission-constrained wind AU - Johnson, Jeremiah X. AU - De Kleine, Robert AU - Keoleian, Gregory A. T2 - Applied Energy AB - Grid-scale energy storage is one option to reduce curtailment and increase deliverability of transmission-constrained wind. This study examines four hypothetical wind and transmission projects in the United States to quantify the reduction in curtailment under various energy storage configurations and determine the cost targets that energy storage must achieve to become a viable solution for use with remote wind. The delivered cost of wind is determined using a power purchase agreement approach and six AC transmission voltage classes are considered. The findings show that curtailment reduction can be achieved with energy storage costs as high as $780/kW with ten hours of storage capacity, a value that is 50–85% lower than current cost estimates for redox and sodium sulfur batteries. Batteries with higher power ratings result in greater curtailment reduction, but also lower maximum viable costs. Sizing the battery to reduce a small portion of curtailment allows for higher utilization of the storage and supports higher cost batteries. Using energy storage to increase wind installed capacity can also be economically viable, but at costs lower than those for curtailment reduction. The results were most sensitive to the elimination of wind subsidies, the installed cost of transmission, battery efficiency degradation, and battery cycle life. The study did not show economic viability for the use of energy storage to reduce transmission voltage class. DA - 2014/7// PY - 2014/7// DO - 10.1016/j.apenergy.2014.03.006 VL - 124 SP - 377-388 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/j.apenergy.2014.03.006 DB - Crossref ER - TY - JOUR TI - Erratum for “Modeling Seasonal Heteroscedasticity in Vehicular Traffic Condition Series Using a Seasonal Adjustment Approach” by Guogang Shi, Jianhua Guo, Wei Huang, and Billy M. Williams AU - Shi, Guogang AU - Guo, Jianhua AU - Huang, Wei AU - Williams, Billy M. T2 - Journal of Transportation Engineering DA - 2014/9// PY - 2014/9// DO - 10.1061/(ASCE)TE.1943-5436.0000687 VL - 140 IS - 9 SP - 08014002 J2 - J. Transp. Eng. LA - en OP - SN - 0733-947X 1943-5436 UR - http://dx.doi.org/10.1061/(ASCE)TE.1943-5436.0000687 DB - Crossref ER - TY - CHAP TI - Unified Constitutive Modeling of Haynes 230 for Isothermal Creep-Fatigue Responses AU - Barrett, Paul Ryan AU - Menon, Mamballykalathil AU - Hassan, Tasnim T2 - Challenges In Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials A2 - Antoun, Bonnie A2 - Qi, H. Jerry A2 - Hall, Richard A2 - Tandon, G.P. A2 - Lu, Hongbing A2 - Lu, Charles A2 - Furmanski, Jevan A2 - Amirkhizi, Alireza T3 - Conference Proceedings of the Society for Experimental Mechanics Series PY - 2014/// DO - 10.1007/978-3-319-00852-3_20 VL - 2 SP - 175–185 PB - Springer International Publishing SN - 9783319008516 9783319008523 UR - http://dx.doi.org/10.1007/978-3-319-00852-3_20 ER - TY - CHAP TI - Haynes 230 High Temperature Thermo-Mechanical Fatigue Constitutive Model Development AU - Ahmed, Raasheduddin AU - Menon, M. AU - Hassan, Tasnim T2 - Challenges In Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials A2 - Antoun, Bonnie A2 - Qi, H. Jerry A2 - Hall, Richard A2 - Tandon, G.P. A2 - Lu, Hongbing A2 - Lu, Charles A2 - Furmanski, Jevan A2 - Amirkhizi, Alireza T3 - Conference Proceedings of the Society for Experimental Mechanics Series AB - Service temperatures of propulsion turbine engine combustor components can be as high as 1,800 °F. This induces a thermo-mechanical fatigue (TMF) loading which, as a result of dwell periods and cyclic loadings, eventually leads to failure of the components via creep-fatigue processes. A large set of isothermal and anisothermal experiments have been carried out on Haynes 230, in an effort to understand its high temperature fatigue constitutive response. Isothermal experiments at different loading strain rates show that the material can be considered to be rate-independent below and at 1,400 °F. However, isothermal strain hold experiments show stress relaxations below and at 1,400 °F. The out-of-phase strain-controlled TMF experiments show a mean stress response. A Chaboche based viscoplastic constitutive model with various features is under development with the final objective of predicting the strains in an actual combustor liner in service through finite element simulation for fatigue lifing. Temperature rate terms have been found to improve hysteresis loop shape simulations and static recovery terms are essential in modeling stress relaxation at temperatures where the behavior is overall rate-independent. It is anticipated that the new modeling feature of mean stress evolution will model the experimentally observed thermo-mechanical mean stress evolution. PY - 2014/// DO - 10.1007/978-3-319-00852-3_17 VL - 2 SP - 151–160 PB - Springer International Publishing SN - 9783319008516 9783319008523 UR - http://dx.doi.org/10.1007/978-3-319-00852-3_17 ER - TY - CHAP TI - High Temperature Multiaxial Creep-Fatigue and Creep-Ratcheting Behavior of Alloy 617 AU - Quayyum, Shahriar AU - Sengupta, Mainak AU - Choi, Gloria AU - Lissenden, Clifford J. AU - Hassan, Tasnim T2 - Challenges In Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials A2 - Antoun, Bonnie A2 - Qi, H. Jerry A2 - Hall, Richard A2 - Tandon, G.P. A2 - Lu, Hongbing A2 - Lu, Charles A2 - Furmanski, Jevan A2 - Amirkhizi, Alireza T3 - Conference Proceedings of the Society for Experimental Mechanics Series AB - Nickel based Alloy 617 is one of the leading candidate materials for intermediate heat exchanger (IHX) of the next generation nuclear plant (NGNP). The IHX is anticipated to operate at temperatures between 800 °C and 950 °C, which is in the creep regime. In addition, system start-ups and shut-downs will induce low cycle fatigue (LCF) damages in the IHX components. Hence, designing IHX using Alloy 617 for NGNP construction will require a detailed understanding of the creep-fatigue and ratcheting responses. In this study, a broad set of multiaxial creep-fatigue and ratcheting experiments are performed and the results are critically evaluated. Experiments are conducted by prescribing multiaxial loading histories in axial and shear, stress and strain space at 850 °C and 950 °C with different strain rates and strain amplitudes. Experimental results revealed that the axial strain ratcheting and cyclic hardening/softening responses of Alloy 617 vary significantly with temperature levels, strain rates and strain amplitudes indicating the dependence of creep-fatigue and ratcheting responses on these parameters. A unified constitutive model (UCM) based on the Chaboche framework is developed and validated against the multiaxial experimental responses. UCM simulated responses are compared against the experimental responses for determining the current state of material modeling and if modeling improvement are needed for IHX design applications. PY - 2014/// DO - 10.1007/978-3-319-00852-3_10 VL - 2 SP - 83–97 PB - Springer International Publishing SN - 9783319008516 9783319008523 UR - http://dx.doi.org/10.1007/978-3-319-00852-3_10 ER - TY - JOUR TI - Bacterial growth and respiration in laminar flow microbial fuel cells AU - Fraiwan, Arwa AU - Call, Douglas F. AU - Choi, Seokheun T2 - Journal of Renewable and Sustainable Energy AB - Application of micro-scale microbial fuel cells (MFCs) to power electronics is limited due to the high internal resistances associated with membranes. Laminar flow MFCs (LFMFCs) provide an advantage over conventional designs because the anode and the cathode are naturally separated due to the laminar flow regime that develops within the reactor, eliminating the need for membranes. However, our ability to fully harness the potential of LFMFC technology lags from a lack of in-depth understanding of anode/cathode analyte mixing and fundamental factors that maximize LFMFC's power-generating capabilities. We, therefore, investigated the anode colonization and respiration of the known exoelectrogenic bacterium, Geobacter sulfurreducens, in a micro-scale LFMFC. Current production was dependent on the location of the anode relative to the influent in continuous-flow operation, with the highest current density of 6.5 μA/cm2 recorded closest to the influent. Lateral diffusion of anode/cathode analytes, in addition to upstream substrate consumption, likely resulted in the observed differences in current production. As current increased, the number of bacterial cells on the anode measured using simultaneous microscopic observation, also increased. Although the current density obtained here was substantially lower than other micro-sized MFCs, these findings show that micro-scale LFMFCs adapted to microscopic observation can provide a unique tool for better understanding real-time anode colonization and overall reactor performance. DA - 2014/3// PY - 2014/3// DO - 10.1063/1.4873399 VL - 6 IS - 2 SP - 023125 J2 - Journal of Renewable and Sustainable Energy LA - en OP - SN - 1941-7012 UR - http://dx.doi.org/10.1063/1.4873399 DB - Crossref ER - TY - CONF TI - Modeling the Role of Social Networks in Situational Awareness and Hazard Communication AU - Albert, Alex AU - Hallowell, Matthew R. T2 - Construction Research Congress 2014 AB - Hazard recognition and communication is critical for preventing injuries on construction projects. Across the industry, employers encourage workers to conduct regular prejob safety meetings and hazard analyses to identify, communicate, and mitigate site-based hazards. Although such programs promote safety, potential benefits often are lost because of inefficient communication channels, differences in language proficiency, and poor safety culture. In this study, we use social network analysis (SNA) to explore the relationship between patterns of worker interaction and situational hazard awareness on active projects in the United States. Specifically, we gathered hazard recognition and communication level data from 18 active construction crews involved in diverse projects and trades through field observations, measured and modeled safety interaction among crew members using social network analysis, and related network characteristics with situational awareness capability of the crews. The results of the study provide strong evidence suggesting that well-connected crews with higher network density outperform poorly connected crews in identifying and communicating hazards. As a result, it is necessary that safety practitioners not only implement traditional program elements but also promote efficient and frequent interaction among workers of all trades. C2 - 2014/5/13/ C3 - Construction Research Congress 2014 DA - 2014/5/13/ DO - 10.1061/9780784413517.179 PB - American Society of Civil Engineers SN - 9780784413517 UR - http://dx.doi.org/10.1061/9780784413517.179 DB - Crossref ER - TY - CONF TI - Strengthening Coastal Sand Dunes Using Microbial-Induced Calcite Precipitation AU - Shanahan, C. AU - Montoya, B. M. T2 - Geo-Congress 2014 AB - In the event of large storms, coastal regions are particularly vulnerable. The effect of erosion on coastal soils can be devastating and may result in damage to structures, roadways, and utilities. This damage can be extremely costly and may result in serious harm. Previous work has shown that the strength and stiffness of loose, saturated sand increases by utilizing microbial-induced carbonate precipitation (MICP). The work presented herein applies the MICP treatment process to sandy coastal soil to increase its resistance to erosion. Utilizing the MICP treatment technique in unsaturated soils, rigid-wall soil column tests were conducted. The soil tested was clean fine sand, typical of coastal dune deposits. The soil remained unsaturated by allowing free drainage during treatments. Shear strength was measured through unconfined compression testing. By upscaling the treatment process, a bench model simulating a costal sand dune was tested to determine the change in the angle of repose for the MICP treated soil and its increase in erosion resistance. Erosion due to wave action was assessed by comparing the behavior of an untreated model sand dune to a MICP treated model sand dune subjected to simulated waves. C2 - 2014/2/24/ C3 - Geo-Congress 2014 Technical Papers DA - 2014/2/24/ DO - 10.1061/9780784413272.165 PB - American Society of Civil Engineers SN - 9780784413272 UR - http://dx.doi.org/10.1061/9780784413272.165 DB - Crossref ER - TY - CONF TI - Numerical Investigation of Microbial-Induced Cemented Sand Mechanical Behavior AU - Feng, K. AU - Montoya, B. M. AU - Evans, T. M. T2 - Geo-Congress 2014 AB - Microbial-induced carbonate precipitation (MICP) has been proven to be an effective method to stabilize problem soils using natural biological processes. Previous triaxial tests show the stiffness and strength of loose sand can be increased significantly by bio-cementation under drained and undrained conditions. Modeling using the discrete element method (DEM) provides a means to evaluate the micromechanics of sands and bond structure degradation during shearing, which are not easily captured in physical experiments. After calibrating with stress-strain behavior observed from microbial-induced cemented sands in physical tests, a numerical model is used to explore the mechanical response of microbial-induced cemented sands under varying loading and unloading stress paths. C2 - 2014/2/24/ C3 - Geo-Congress 2014 Technical Papers DA - 2014/2/24/ DO - 10.1061/9780784413272.161 PB - American Society of Civil Engineers SN - 9780784413272 UR - http://dx.doi.org/10.1061/9780784413272.161 DB - Crossref ER - TY - JOUR TI - Empirical assessment of route choice impact on emissions over different road types, traffic demands, and driving scenarios AU - Bandeira, Jorge M. AU - Carvalho, Dário O. AU - Khattak, Asad J. AU - Rouphail, Nagui M. AU - Fontes, Tânia AU - Fernandes, Paulo AU - Pereira, Sérgio R. AU - Coelho, Margarida C. T2 - International Journal of Sustainable Transportation AB - ABSTRACTEco-routing has been shown as a promising strategy to reduce emissions. However, during peak periods, with limited additional capacity, the eco-friendliness of various routes may change. We have explored this issue empirically by covering about 13,300 km, in three different areas, using GPS-equipped vehicles to record second-by-second vehicle dynamics. This study has confirmed the importance of the eco-routing concept given that the selection of eco-friendly routes can lead to significant emissions savings. Furthermore, these savings are expected to be practically unchanged during the peak period. However, some potential negative externalities may arise from purely dedicated eco-friendly navigation systems. DA - 2014/11/5/ PY - 2014/11/5/ DO - 10.1080/15568318.2014.901447 VL - 10 IS - 3 SP - 271-283 J2 - International Journal of Sustainable Transportation LA - en OP - SN - 1556-8318 1556-8334 UR - http://dx.doi.org/10.1080/15568318.2014.901447 DB - Crossref KW - Congestion KW - eco-routing KW - emissions KW - microscope modeling KW - route choice KW - vehicle-specific power ER - TY - JOUR TI - Special Issue on Construction Engineering: Leveraging Project and Career Success AU - Goodrum, Paul M. AU - Jaselskis, Edward J. AU - Lucko, Gunnar AU - Schexnayder, Cliff AU - Schaufelberger, John AU - Tatum, Clyde B. AU - de la Garza, Jesus M. T2 - Practice Periodical on Structural Design and Construction AB - This is the second special issue dedicated to the Construction Engineering Conference. The first issue coincided with the inaugural conference gathering at Virginia Tech in 2011. It was published through the ASCE Journal of Construction Engineering and Management. We are as pleased and as proud now as we were then to present a series of papers that bridge construction engineering academics and industry practitioners. The need for increased collaboration between academia and the industry has not subsided, and will not subside in the foreseeable future. The construction engineering academic community faces the challenge of maintaining a balanced research portfolio of both basic and applied research. Both types of research are dependent on each other in the overall spectrum of our community and feed the cycle of continuous improvement in the engineering and construction industry’s performance. Furthermore, in an industry where industry practices are constantly evolving, what and how we teach students most also keep pace with industry changes. The papers contained in this special issue follow three primary themes that mirror the theme of the overall 2014 Construction Engineering Conference. The first theme focuses on aspects of knowledge and career paths for future success. Many of these particular papers focus on the challenges, benefits, and lessons learned integrating industry knowledge into education and research at the universities. The second and third themes, sustainability and building informationmodeling (BIM), focus on specific areas of new knowledge that will continue to become increasingly critical for both the success of individuals and also the industry at large. Papers along these particular themes focus on how sustainability andBIM are not only being implemented in the industry, but how these relatively new practices are being addressed in university curriculums. Most, not all, papers were written by a team of industry and academic authors. In many cases, this was the first opportunity for the authors to meet and work on a collaborative effort. It is the hope of the conference’s organizing committee that these individual collaborations will plant the seeds for broader industry/ academic partnerships. A debt of gratitude is owed to the special issue author group for their thoughts and efforts in this overall body of work. Furthermore, we are especially grateful to the reviewers, whomade sure that the papers maintained the standards for publication in the ASCE’s Practice Periodical on Structural Design and Construction. DA - 2014/2// PY - 2014/2// DO - 10.1061/(ASCE)SC.1943-5576.0000211 VL - 19 IS - 1 SP - 1-1 J2 - Pract. Period. Struct. Des. Constr. LA - en OP - SN - 1084-0680 1943-5576 UR - http://dx.doi.org/10.1061/(ASCE)SC.1943-5576.0000211 DB - Crossref ER - TY - JOUR TI - Flood Risk Management: The Need for Sound Policies and Practices AU - Traver, Robert AU - Andersen, Christine AU - Edge, Billy AU - Fowler, David AU - Calloway, Gerald, Jr. AU - Gilbert, Robert B. AU - Haddock, Carol AU - Link, Lewis E. AU - Moyle, John AU - Roth, Lawrence AU - Whitlock, P. Kay AU - Ludy, Jessica AU - Durrant, John AU - Whitten, Barbara T2 - Civil Engineering Magazine Archive AB - A large portion of the destruction from Hurricane Katrina in 2005 was caused not only by the storm itself but also by the storm’s exposure of engineering and engineering-related policy failures. ASCE’s Hurricane Katrina External Review Panel, which was convened at the request of Lieutenant General Carl A. Strock, P.E., M.ASCE, then the commander and chief engineer of the U.S. Army Corps of Engineers, to conduct an in-depth peer review of the comprehensive work of the Corp’s Interagency Performance Evaluation Task Force, published its report, entitled The New Orleans Hurricane Protection System: What Went Wrong and Why, in May 2007. In January 2012 ASCE’s Board of Direction established the Task Committee on Flood Safety Policies and Practices (TCFSPP) to examine the findings put forth in the report, to determine whether progress has been made in implementing the calls for action included in this report, and to determine if the American public is now safer from the dangers of flooding. This article is a distillation of the TCFSPP’s report, which will be published by ASCE later this year. DA - 2014/4// PY - 2014/4// DO - 10.1061/CIEGAG.0000489 VL - 84 IS - 4 SP - 48-57 J2 - Civ. Eng. LA - en OP - SN - 2381-0688 2381-0688 UR - http://dx.doi.org/10.1061/CIEGAG.0000489 DB - Crossref ER - TY - CONF TI - Numerical Analysis of Strengthened Steel Stud Bearing Walls to Resist Disproportionate Collapse AU - Mohamed, Ismail AU - Rahman, Nabil A. AU - Seracino, R. T2 - Structures Congress 2014 AB - Cold-formed steel stud load bearing walls have three framing components that can be utilized to enhance the resistance to disproportionate collapse in case of wall section removal from the structure: the wall lateral bracing, the wall studs, and added diagonal tension straps. Strengthening of the walls with tension straps has shown to redistribute the load of the lost wall section to the system and to enhance the resistance to disproportionate collapse in a previous paper of the authors. This paper extends the findings of the single multi-story wall system to the full 3D structure. The effects of the 3D interaction and the membrane action of the composite floor deck are investigated. The redistributed load after wall section removal is supported by the added wall strengthening system. The double studs showed effectiveness in preventing the wall from experiencing disproportionate collapse. Due to the rigidity of the composite deck floor, the diagonal strap system did not carry much force but it helped to redistribute the loads to other parts of the building. C2 - 2014/4/2/ C3 - Structures Congress 2014 DA - 2014/4/2/ DO - 10.1061/9780784413357.191 PB - American Society of Civil Engineers SN - 9780784413357 UR - http://dx.doi.org/10.1061/9780784413357.191 DB - Crossref ER - TY - CONF TI - Empirical Acceptance-Resistance Agent-Based Modeling Approach for Simulating the Adoption of Water Reuse AU - Kandiah, Venu K. AU - Berglund, Emily Z. AU - Binder, Andrew R. T2 - World Environmental and Water Resources Congress 2014 AB - Though water reuse provides a promising and sustainable alternative for urban water supply, wide-scale implementation of water reuse within an existing water infrastructure system is challenged by the need for community-wide public acceptance and adoption. The public has historically perceived recycled water negatively, and, as a consequence, water reuse is typically omitted in the development of municipal water management plans. Consumer's base acceptance and rejection of new technologies on an intuitive analysis of their risks and benefits and their perceptions may change over time based on interactions with other consumers, decision makers, and engineering infrastructure systems. This research creates a modeling framework to simulate the changing perceptions of consumers and their adoption of water reuse. The modeling framework is used to develop understanding about the mechanisms that drive the dynamic evolution of perceptions, which can aid the planning and decision-making process for the integration of water reuse within existing water systems. This research develops an acceptance-resistance agent-based model to simulate the adoption and rejection of water reuse based on a "risk publics" framework, which is a theoretical model of how different groups perceive new technologies. The risk publics framework uses the perception of risk and benefits to determine the potential of households to adopt or resist new technology. Consumers are represented as agents, and their behaviors and attributes are developed using survey data of the U.S. population, which measures attitudes, knowledge, and behavioral intentions for recycled water. The data are analyzed to determine empirical relationships among individuals, the presence of social groups, and informational and communicative variables governing individual use of reclaimed water. The variables are encoded in the agent-based modeling framework to simulate the key social mechanisms that affect consumer acceptance of water reuse. The framework couples the acceptance-resistance agent-based model of consumers, an agent-based model of utility management, and water distribution system models of the drinking and reclaimed water systems. The framework will be used to explore the interactions among consumer behavior, management strategies, water reuse infrastructure, and the existing water supply infrastructure with adoption of water reuse. C2 - 2014/5/29/ C3 - World Environmental and Water Resources Congress 2014 DA - 2014/5/29/ DO - 10.1061/9780784413548.183 PB - American Society of Civil Engineers SN - 9780784413548 UR - http://dx.doi.org/10.1061/9780784413548.183 DB - Crossref ER - TY - CONF TI - Complex Adaptive System Framework to Simulate Adaptations of Human-Environmental Systems to Climate Change and Urbanization: The Verde River Basin AU - Al-Amin, Shams AU - Berglund, Emily Z. AU - Larson, Kelli L. T2 - World Environmental and Water Resources Congress 2014 AB - Water management in the arid western United States must address imminent increases in freshwater withdraws due to population growth and climate change. Stresses in the water supply system can be addressed through demand management, which restricts water uses or instates bans, incentivizes toilet retrofits or landscape conversions, and encourages conservation through outreach and education. These policies rely on the behaviors, compliance, and conservation of residential and agricultural users. This research develops a complex adaptive system (CAS) framework to analyze the dynamic interactions between changing water demands and limited water resources for population growth, land use conversion, and climate change scenarios. Water supply and demand for the arid Verde River Basin is explored through an agent-based model (ABM). Three types of agents are encoded, including policy makers (utility managers/planners) and agricultural and residential water users. Agents are initialized with business-as-usual behaviors, a set of signals, demand-reduction actions, and supply-augmentation actions. ABMs are coupled with water infrastructure models, which are in turn forced with hydro-climate and water demand projections to capture the feedbacks and simulate policy and consumer-level agents' roles in promoting balance between water demands and supplies. To determine the dynamics of societal responses to hydro-climatic extremes and the likelihood of water system adaptations to environmental change in the future, this research explores data about sociopolitical responses and actions by analyzing existing policies and management strategies. By synthesizing these data, a timeline of events and estimates for the relative probability of actions being taken are generated and used to encode policy-maker agents. The ABM framework provides important insights into the dynamic interaction of sociotechnical variables by simulating potential feedbacks of human-environmental and hydro-ecological systems that arise from adaptations to climate change and growth. Insight gained through this simulation study can be used to guide policy making under changing hydro-climatic scenarios over a long-term planning horizon. C2 - 2014/5/29/ C3 - World Environmental and Water Resources Congress 2014 DA - 2014/5/29/ DO - 10.1061/9780784413548.181 PB - American Society of Civil Engineers SN - 9780784413548 UR - http://dx.doi.org/10.1061/9780784413548.181 DB - Crossref ER - TY - CONF TI - Multiobjective Optimization to Explore Tradeoffs in Rainwater Harvesting Strategies for Urban Water Sustainability AU - Ali, Alireza Mashhadi AU - Kandiah, Venu AU - Berglund, Emily Zechman T2 - World Environmental and Water Resources Congress 2014 AB - Urban water systems are designed for centralized management, where water is collected at a central location, treated, and delivered to a population of users through a pipe network. Decentralized systems may generate water and energy savings beyond conventional approaches, as they reduce the demands on the potable drinking water system and the energy required for treatment and conveyance. For example, rainwater harvesting systems that are installed at individual lots can be used to capture and reuse rainwater to irrigate lawns. This research explores the tradeoffs among infrastructure costs, energy savings, and water savings as consumers adopt rainwater harvesting within an existing centralized water supply system. The presence of rainwater harvesting within a community of individual households is a sociotechnical process, as interactions among existing water supply infrastructure, utility managers, and consumers can influence the adoption of decentralized technologies and the performance of centralized infrastructure. The urban water supply system is simulated as a complex adaptive system to analyze the water use behavior of consumers and their influence on system-level sustainability. An agent-based model is constructed to simulate households as water-consumer agents and is coupled with a system dynamics simulation of a water reservoir to capture the feedbacks that drive the household-level adoption of rainwater harvesting. An evolutionary computation approach is coupled with the agent-based modeling framework to optimize multiple objectives and explore tradeoffs among energy requirements, water savings, and the cost of rainwater harvesting systems. The framework is demonstrated for a virtual case study to develop management strategies for sizing rainwater harvesting cisterns and achieving sustainability goals for a sociotechnical water supply system. C2 - 2014/5/29/ C3 - World Environmental and Water Resources Congress 2014 DA - 2014/5/29/ DO - 10.1061/9780784413548.180 PB - American Society of Civil Engineers SN - 9780784413548 UR - http://dx.doi.org/10.1061/9780784413548.180 DB - Crossref ER - TY - CONF TI - An Agent-Based Modeling Approach to Simulate the Dynamics of Water Supply and Water Demand AU - Ali, Alireza Mashhadi AU - Shafiee, M. Ehsan AU - Berglund, Emily Zechman AU - Arumugam, Sankarasubramanian T2 - World Environmental and Water Resources Congress 2014 AB - Water resources management requires an insightful balance between water demand and water supply. U.S. water supply is at risk of shortage due to population growth, land use changes, climate change, and water use behaviors of customers. Long-term water supply planning is conventionally based on projections of population growth and demands; however, the sustainability of water resources depends on the dynamic interactions among the environmental, technological, and social characteristics of the water system and local population. This research develops a sociotechnical model to simulate the interactions among the social and engineering systems. An agent-based model (ABM) is used to simulate households and water-use behaviors and is coupled with a set of technical models, including climate change projections, a hydrological watershed model, and a water reservoir model. The ABM framework simulates population growth as an increase in the number of household agents, which affects the water supply and demand balance through increasing demands. Household agents increase irrigation demands due to climate change and decrease indoor demands as they adopt low-flow appliances. Agents also respond to drought restrictions by limiting their use of water for outdoor application. The effects of these actions on the reservoir storage are simulated using engineering models and data describing the climatological and hydrological conditions of the watershed. The ABM framework is developed and demonstrated for the Raleigh, North Carolina, water supply system, which withdraws water from the Falls Lake Reservoir. The model is tested against historic data (1983-2013) and is used to explore the effectiveness of policies for the period 2013-2033. Conservation programs and drought restrictions are simulated to evaluate the need to develop new water sources in the future. The ABM framework facilitates simulations that generate new insight about the dynamics involved in the sustainability of water supply and demand. C2 - 2014/5/29/ C3 - World Environmental and Water Resources Congress 2014 DA - 2014/5/29/ DO - 10.1061/9780784413548.179 PB - American Society of Civil Engineers SN - 9780784413548 UR - http://dx.doi.org/10.1061/9780784413548.179 DB - Crossref ER - TY - CONF TI - Tradeoffs in Public Acceptance and Water Savings in Using Reclaimed Water for Irrigation Applications AU - Schmidt, Michelle AU - Berglund, Emily Zechman AU - Binder, Andrew T2 - World Environmental and Water Resources Congress 2014 AB - Water scarcity is a growing concern, due to stresses imposed by climate change, population growth, and urbanization. Reclaimed water is a reliable source that can be produced by treating wastewater and used to supplement nonpotable demands. According to the U.S. Geological Survey, 128 billion gallons of water are used per day for agricultural irrigation, accounting for roughly 31% of total water usage in the United States. Reclaimed water is a viable option for irrigation applications; however, the success of reclaimed water programs can be affected by public support. This research develops an approach for assessing water savings and acceptability for irrigation applications of reclaimed water. The potential for using reclaimed water in Wake County, North Carolina, is explored through the use of a modeling framework. Potential water savings are evaluated based on the volume of wastewater produced and irrigation demands. The perceptions of using reclaimed water are compared for diverse irrigation applications using results from a recently conducted national survey. Results demonstrate that acceptability for using reclaimed water to irrigate public parks, athletic fields, and residential lawns is higher than the acceptability of use for irrigating food crops. Tradeoffs between public acceptance and the potential reduction of water stress are explored to provide guidance for Wake County infrastructure planning. The modeling methodology is general and can be applied to determine water reclamation potential at the county level across the United States. C2 - 2014/5/29/ C3 - World Environmental and Water Resources Congress 2014 DA - 2014/5/29/ DO - 10.1061/9780784413548.051 PB - American Society of Civil Engineers SN - 9780784413548 UR - http://dx.doi.org/10.1061/9780784413548.051 DB - Crossref ER - TY - JOUR TI - Self-Healing: Continuous Self-Healing Life Cycle in Vascularized Structural Composites (Adv. Mater. 25/2014) AU - Patrick, Jason F. AU - Hart, Kevin R. AU - Krull, Brett P. AU - Diesendruck, Charles E. AU - Moore, Jeffrey S. AU - White, Scott R. AU - Sottos, Nancy R. T2 - Advanced Materials AB - By incorporating three-dimensional microvascular networks within a woven glass fiber-reinforced polymer composite N. R. Sottos, S. R. White, and co-workers demonstrate on page 4302 the full recovery (>100%) of mode-I fracture resistance after multiple damage events. This optical image of a fracture plane reveals efficient delivery, mixing and polymerization of the fluorescently dyed, two-part reactive healing chemistry. DA - 2014/7// PY - 2014/7// DO - 10.1002/ADMA.201470166 VL - 26 IS - 25 SP - 4189-4189 J2 - Adv. Mater. LA - en OP - SN - 0935-9648 UR - http://dx.doi.org/10.1002/ADMA.201470166 DB - Crossref ER - TY - JOUR TI - Evolutionary Computation-based Decision-making Framework for Designing Water Networks to Minimize Background Leakage AU - Shafiee, M.E. AU - Berglund, A. AU - Berglund, E. Zechman AU - Brill, E. Downey, Jr. AU - Mahinthakumar, G. T2 - Procedia Engineering AB - Abstract This research minimizes the impact of leaks on the operation of the system to reduce lost water while meeting typical management goals. A genetic algorithm approach is implemented within a high-performance computing platform to select tank sizes, pump placement and operations, placement of pressure control valves, and pipe diameters for replacing pipes. It identifies solutions that minimize water loss, operational costs, and capital costs, while maintaining pressure at nodes and operational feasibility for tanks. Multiple problem formulations are solved that use alternative objective functions and allow varying degrees of freedom in the decision space. The methodology is demonstrated to identify a water distribution system re-design for the C-Town case study. DA - 2014/// PY - 2014/// DO - 10.1016/J.PROENG.2014.11.167 VL - 89 SP - 118-125 J2 - Procedia Engineering LA - en OP - SN - 1877-7058 UR - http://dx.doi.org/10.1016/J.PROENG.2014.11.167 DB - Crossref KW - genetic algorithm KW - water distribution system design KW - rehabilitation KW - infrastructure management ER - TY - JOUR TI - Battle of the Water Networks II AU - Marchi, Angela AU - Salomons, Elad AU - Ostfeld, Avi AU - Kapelan, Zoran AU - Simpson, Angus R. AU - Zecchin, Aaron C. AU - Maier, Holger R. AU - Wu, Zheng Yi AU - Elsayed, Samir M. AU - Song, Yuan AU - Walski, Tom AU - Stokes, Christopher AU - Wu, Wenyan AU - Dandy, Graeme C. AU - Alvisi, Stefano AU - Creaco, Enrico AU - Franchini, Marco AU - Saldarriaga, Juan AU - Páez, Diego AU - Hernández, David AU - Bohórquez, Jessica AU - Bent, Russell AU - Coffrin, Carleton AU - Judi, David AU - McPherson, Tim AU - van Hentenryck, Pascal AU - Matos, José Pedro AU - Monteiro, António Jorge AU - Matias, Natércia AU - Yoo, Do Guen AU - Lee, Ho Min AU - Kim, Joong Hoon AU - Iglesias-Rey, Pedro L. AU - Martínez-Solano, Francisco J. AU - Mora-Meliá, Daniel AU - Ribelles-Aguilar, José V. AU - Guidolin, Michele AU - Fu, Guangtao AU - Reed, Patrick AU - Wang, Qi AU - Liu, Haixing AU - McClymont, Kent AU - Johns, Matthew AU - Keedwell, Edward AU - Kandiah, Venu AU - Jasper, Micah Nathanael AU - Drake, Kristen AU - Shafiee, Ehsan AU - Barandouzi, Mehdy Amirkhanzadeh AU - Berglund, Andrew David AU - Brill, Downey AU - Mahinthakumar, Gnanamanikam AU - Ranjithan, Ranji AU - Zechman, Emily Michelle AU - Morley, Mark S. AU - Tricarico, Carla AU - de Marinis, Giovanni AU - Tolson, Bryan A. AU - Khedr, Ayman AU - Asadzadeh, Masoud T2 - Journal of Water Resources Planning and Management AB - The Battle of the Water Networks II (BWN-II) is the latest of a series of competitions related to the design and operation of water distribution systems (WDSs) undertaken within the Water Distribution Systems Analysis (WDSA) Symposium series. The BWN-II problem specification involved a broadly defined design and operation problem for an existing network that has to be upgraded for increased future demands, and the addition of a new development area. The design decisions involved addition of new and parallel pipes, storage, operational controls for pumps and valves, and sizing of backup power supply. Design criteria involved hydraulic, water quality, reliability, and environmental performance measures. Fourteen teams participated in the Battle and presented their results at the 14th Water Distribution Systems Analysis conference in Adelaide, Australia, September 2012. This paper summarizes the approaches used by the participants and the results they obtained. Given the complexity of the BWN-II problem and the innovative methods required to deal with the multiobjective, high dimensional and computationally demanding nature of the problem, this paper represents a snap-shot of state of the art methods for the design and operation of water distribution systems. A general finding of this paper is that there is benefit in using a combination of heuristic engineering experience and sophisticated optimization algorithms when tackling complex real-world water distribution system design problems. DA - 2014/7// PY - 2014/7// DO - 10.1061/(ASCE)WR.1943-5452.0000378 VL - 140 IS - 7 SP - 04014009 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(ASCE)WR.1943-5452.0000378 DB - Crossref KW - Water distribution systems KW - Optimization KW - Design KW - Pump operation ER - TY - CONF TI - Development of an Industry Level Productivity Metric for the Construction Industry AU - Vereen, Stephanie AU - Hummer, Joseph E. AU - Rasdorf, William T2 - Construction Research Congress 2014 AB - Construction industry labor productivity is an important metric that provides feedback about task, project, and industry level trends and improvements. However, labor productivity for the construction industry historically has been elusive to define, both qualitatively and quantitatively. Existing research studies and methods have provided different calculation methods at a variety of levels (task, project, industry), but none proved universally satisfying. This study generated a new metric using RS MeansBuilding Construction Cost Data. The metric was derived using labor and cost information from a sample of RS Means' construction activities. The sampled data were indexed and combined to generate labor productivity metrics (output per labor hour and output per labor cost). The research findings present a construction industry productivity metric based on RS Means' data that is reliable, repeatable, and developed from a consistent and accurate data source. The study results showed a slightly sporadic but consistent decline in both output per labor hour and cost from 1990 through 2012. With this new metric, construction professionals now will be able to analyze industry level productivity by means of a commonly used industry reference manual. C2 - 2014/5/13/ C3 - Construction Research Congress 2014 DA - 2014/5/13/ DO - 10.1061/9780784413517.082 PB - American Society of Civil Engineers SN - 9780784413517 UR - http://dx.doi.org/10.1061/9780784413517.082 DB - Crossref ER - TY - CONF TI - Methodology to Forecast the Emissions from Construction Equipment for a Transportation Construction Project AU - Arocho, Ingrid AU - Rasdorf, William AU - Hummer, Joseph T2 - Construction Research Congress 2014 AB - The objective of initiating sustainability principles is to build structures with reduced environmental effects. The success of achieving this objective usually is measured during the operations and maintenance phases of the project. However, the effect of the construction phase itself, particularly that of construction equipment, is sometimes overlooked. This paper presents a methodology to forecast emissions during construction, thereby providing a chance to quantify construction emissions and develop strategies to mitigate them. The methodology is demonstrated for a road construction project that includes utility work. The methodology forecasts the quantity of pollutants emitted by construction vehicles and equipment and the fuel used based on project characteristics, such as cost and total area of pavement. Data were obtained from the contractor, RS Means, and the U.S. Environmental Protection Agency. The pollutants addressed include CO2, NOx, hydrocarbons, CO, particulate matter, and SO2. The results of this research show that demolition activities are the largest contributors to emissions. They also show that front-end loaders and backhoe loaders produce significantly greater emissions than some other equipment types. Construction and design professionals can use the results from this research to forecast emissions and fuel use during the planning and design phases of projects. C2 - 2014/5/13/ C3 - Construction Research Congress 2014 DA - 2014/5/13/ DO - 10.1061/9780784413517.057 PB - American Society of Civil Engineers SN - 9780784413517 UR - http://dx.doi.org/10.1061/9780784413517.057 DB - Crossref ER - TY - JOUR TI - Comparison of Fatigue Damage, Healing, and Endurance Limit with Beam and Uniaxial Fatigue Tests AU - Zeiada, Waleed Abdelaziz AU - Souliman, Mena I. AU - Kaloush, Kamil E. AU - Mamlouk, Michael AU - Underwood, B. Shane T2 - Transportation Research Record: Journal of the Transportation Research Board AB - The concept of an endurance limit assumes a strain value below which the net fatigue damage that occurs during a load cycle is zero. The fact that real traffic loads are separated by rest periods may allow for partial or full healing of the microcracks, which can affect this endurance limit. If the asphalt layer thickness is controlled to keep strains below the endurance limit, the fatigue life of the pavement can be extended considerably. In the study reported in this paper, it was hypothesized that the endurance limit in asphalt concrete developed from the interaction and balance of damage and healing during a load cycle. This hypothesis formed the basis of the testing and analysis program, which evaluated the effects of air voids, asphalt content, rest periods, and temperature on the endurance limit. Two types of fatigue tests were conducted: beam (flexural) and uniaxial. A regression model also was developed on the basis of the results of each test and used to obtain the endurance limit values. This paper compares fatigue damage, healing, and endurance limit results from the two tests under similar conditions. The comparison shows that the beam fatigue test yields less overall fatigue damage and less healing than the uniaxial fatigue test. Beam fatigue yields 8 to 14 times longer fatigue lives, while uniaxial fatigue yields higher healing (10.4 times for the only available case). Because damage and healing combined to govern the endurance limit, the two tests produced close values in which the overall uniaxial endurance limit values were 12% less than the beam fatigue endurance limit values. DA - 2014/1// PY - 2014/1// DO - 10.3141/2447-04 VL - 2447 IS - 1 SP - 32-41 J2 - Transportation Research Record LA - en OP - SN - 0361-1981 2169-4052 UR - http://dx.doi.org/10.3141/2447-04 DB - Crossref ER - TY - JOUR TI - Nonlinear viscoelastic analysis of asphalt cement and asphalt mastics AU - Underwood, B. Shane AU - Kim, Y. Richard T2 - International Journal of Pavement Engineering AB - The nonlinear viscoelastic (NLVE) behaviour of asphalt cement and asphalt mastic are studied using temperature and frequency sweep tests and repeated stress sweep cyclic load tests. These experiments show that the response functions of these materials are strain-level dependent. The experiments also show that NLVE occurs simultaneously with other mechanisms, which complicates isolation and subsequent characterisation. For the asphalt mastics studied, the NLVE is found to relate to only the influences of the asphalt cement. Based on these experiments and analyses, a thermodynamics-based constitutive equation is proposed. The proposed model is chosen based on the hypothesis that the observed NLVE is strain related, which is different from other similar models and agrees with existing frameworks for evaluating damage. The resulting model is found to capably predict the stress–strain behaviour of asphalt cement and asphalt mastics at different volumetric concentrations of filler under cyclic and constant rate loading. DA - 2014/8/7/ PY - 2014/8/7/ DO - 10.1080/10298436.2014.943133 VL - 16 IS - 6 SP - 510-529 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2014.943133 DB - Crossref KW - rheometrical testing KW - modelling KW - asphalt cement KW - nonlinear viscoelastic KW - asphalt mastic ER - TY - JOUR TI - FOGISEW: Modeling FOG Deposit Formation in Sewer Collection System AU - Yousefelahiyeh AU - Roya AU - Dominic AU - Sandeep, Christopher Cyril AU - Ducoste AU - Joel, J T2 - Proceedings of the Water Environment Federation DA - 2014/10/1/ PY - 2014/10/1/ DO - 10.2175/193864714816099365 VL - 2014 IS - 4 SP - 1-10 ER - TY - CONF TI - Investigation of shear response of nuclear power plant wall elements using high strength materials AU - Bae, G.-M. AU - Proestos, G.T. AU - Park, J.-H. AU - Bentz, E.C. AU - Cho, J.-Y. AU - Collins, M.P. C2 - 2014/// C3 - Engineering for Progress, Nature and People DA - 2014/// SP - 867-873 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84929448579&partnerID=MN8TOARS ER - TY - JOUR TI - Genotypic and Phenotypic Characterization of Escherichia coli Isolates from Feces, Hands, and Soils in Rural Bangladesh via the Colilert Quanti-Tray System AU - Julian, Timothy R. AU - Islam, M. Aminul AU - Pickering, Amy J. AU - Roy, Subarna AU - Fuhrmeister, Erica R. AU - Ercumen, Ayse AU - Harris, Angela AU - Bishai, Jason AU - Schwab, Kellogg J. T2 - Applied and Environmental Microbiology AB - ABSTRACT The increased awareness of the role of environmental matrices in enteric disease transmission has resulted in the need for rapid, field-based methods for fecal indicator bacteria and pathogen detection. Evidence of the specificity of β-glucuronidase-based assays for detection of Escherichia coli from environmental matrices relevant to enteric pathogen transmission in developing countries, such as hands, soils, and surfaces, is limited. In this study, we quantify the false-positive rate of a β-glucuronidase-based E. coli detection assay (Colilert) for two environmental reservoirs in Bangladeshi households (hands and soils) and three fecal composite sources (cattle, chicken, and humans). We investigate whether or not the isolation source of E. coli influences phenotypic and genotypic characteristics. Phenotypic characteristics include results of biochemical assays provided by the API-20E test; genotypic characteristics include the Clermont phylogroup and the presence of enteric and/or environmental indicator genes sfmH , rfaI , and fucK . Our findings demonstrate no statistically significant difference in the false-positive rate of Colilert for environmental compared to enteric samples. E. coli isolates from all source types are genetically diverse, representing six of the seven phylogroups, and there is no difference in relative frequency of phylogroups between enteric and environmental samples. We conclude that Colilert, and likely other β-glucuronidase-based assays, is appropriate for detection of E. coli on hands and in soils with low false-positive rates. Furthermore, E. coli isolated from hands and soils in Bangladeshi households are diverse and indistinguishable from cattle, chicken, and human fecal isolates, using traditional biochemical assays and phylogrouping. DA - 2014/12/29/ PY - 2014/12/29/ DO - 10.1128/aem.03214-14 VL - 81 IS - 5 SP - 1735-1743 J2 - Appl. Environ. Microbiol. LA - en OP - SN - 0099-2240 1098-5336 UR - http://dx.doi.org/10.1128/aem.03214-14 DB - Crossref ER - TY - JOUR TI - Enteric Pathogens in Stored Drinking Water and on Caregiver’s Hands in Tanzanian Households with and without Reported Cases of Child Diarrhea AU - Mattioli, Mia Catharine AU - Boehm, Alexandria B. AU - Davis, Jennifer AU - Harris, Angela R. AU - Mrisho, Mwifadhi AU - Pickering, Amy J. T2 - PLoS ONE AB - Diarrhea is one of the leading causes of mortality in young children. Diarrheal pathogens are transmitted via the fecal-oral route, and for children the majority of this transmission is thought to occur within the home. However, very few studies have documented enteric pathogens within households of low-income countries.The presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed in hand rinses and household stored drinking water in Bagamoyo, Tanzania. Using a matched case-control study design, we examined the relationship between contamination of hands and water with these markers and child diarrhea. We found that the presence of ECVG in household stored water was associated with a significant decrease in the odds of a child within the home having diarrhea (OR = 0.51; 95% confidence interval 0.27-0.93). We also evaluated water management and hygiene behaviors. Recent hand contact with water or food was positively associated with detection of enteric pathogen markers on hands, as was relatively lower volumes of water reportedly used for daily hand washing. Enteropathogen markers in stored drinking water were more likely found among households in which the markers were also detected on hands, as well as in households with unimproved water supply and sanitation infrastructure.The prevalence of enteric pathogen genes and the human-specific Bacteroidales fecal marker in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. Better stored water quality among households with diarrhea indicates caregivers with sick children may be more likely to ensure safe drinking water in the home. Interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment. DA - 2014/1/2/ PY - 2014/1/2/ DO - 10.1371/journal.pone.0084939 VL - 9 IS - 1 SP - e84939 J2 - PLoS ONE LA - en OP - SN - 1932-6203 UR - http://dx.doi.org/10.1371/journal.pone.0084939 DB - Crossref ER - TY - JOUR TI - Biochar as a sustainable electrode material for electricity production in microbial fuel cells AU - Huggins, T. AU - Wang, H. AU - Kearns, J. AU - Jenkins, P. AU - Ren, Z.J. T2 - Bioresource Technology AB - Wood-based biochars were used as microbial fuel cell electrodes to significantly reduce cost and carbon footprint. The biochar was made using forestry residue (BCc) and compressed milling residue (BCp). Side-by-side comparison show the specific area of BCp (469.9m(2)g(-1)) and BCc (428.6cm(2)g(-1)) is lower than granular activated carbon (GAC) (1247.8m(2)g(-1)) but higher than graphite granule (GG) (0.44m(2)g(-1)). Both biochars showed power outputs of 532±18mWm(-2) (BCp) and 457±20mWm(-2) (BCc), comparable with GAC (674±10mWm(-2)) and GG (566±5mWm(-2)). However, lower material expenses made their power output cost 17-35US$W(-1), 90% cheaper than GAC (402US$W(-1)) or GG (392US$W(-1)). Biochar from waste also reduced the energy and carbon footprint associated with electrode manufacturing and the disposal of which could have additional agronomic benefits. DA - 2014/4// PY - 2014/4// DO - 10.1016/j.biortech.2014.01.058 VL - 157 SP - 114–119 UR - http://dx.doi.org/10.1016/j.biortech.2014.01.058 KW - Biochar KW - Electrode KW - Microbial fuel cell KW - Bioelectrochemical KW - Electricity ER - TY - JOUR TI - Complete Proteomic-Based Enzyme Reaction and Inhibition Kinetics Reveal How Monolignol Biosynthetic Enzyme Families Affect Metabolic Flux and Lignin in Populus trichocarpa AU - Wang, Jack P. AU - Naik, Punith P. AU - Chen, Hsi-Chuan AU - Shi, Rui AU - Lin, Chien-Yuan AU - Liu, Jie AU - Shuford, Christopher M. AU - Li, Quanzi AU - Sun, Ying-Hsuan AU - Tunlaya-Anukit, Sermsawat AU - Williams, Cranos M. AU - Muddiman, David C. AU - Ducoste, Joel J. AU - Sederoff, Ronald R. AU - Chiang, Vincent L. T2 - The Plant Cell AB - We established a predictive kinetic metabolic-flux model for the 21 enzymes and 24 metabolites of the monolignol biosynthetic pathway using Populus trichocarpa secondary differentiating xylem. To establish this model, a comprehensive study was performed to obtain the reaction and inhibition kinetic parameters of all 21 enzymes based on functional recombinant proteins. A total of 104 Michaelis-Menten kinetic parameters and 85 inhibition kinetic parameters were derived from these enzymes. Through mass spectrometry, we obtained the absolute quantities of all 21 pathway enzymes in the secondary differentiating xylem. This extensive experimental data set, generated from a single tissue specialized in wood formation, was used to construct the predictive kinetic metabolic-flux model to provide a comprehensive mathematical description of the monolignol biosynthetic pathway. The model was validated using experimental data from transgenic P. trichocarpa plants. The model predicts how pathway enzymes affect lignin content and composition, explains a long-standing paradox regarding the regulation of monolignol subunit ratios in lignin, and reveals novel mechanisms involved in the regulation of lignin biosynthesis. This model provides an explanation of the effects of genetic and transgenic perturbations of the monolignol biosynthetic pathway in flowering plants. DA - 2014/3// PY - 2014/3// DO - 10.1105/tpc.113.120881 VL - 26 IS - 3 SP - 894-914 J2 - Plant Cell LA - en OP - SN - 1040-4651 1532-298X UR - http://dx.doi.org/10.1105/tpc.113.120881 DB - Crossref ER - TY - JOUR TI - Degraded secant modulus for permanent deformation of soils AU - Ahn, Jaehun AU - Gabr, Mohammed AU - Oh, Jeongho AU - Shin, Hosung T2 - International Journal of Pavement Engineering AB - Two constitutive models, one with five parameters and the other with three parameters, were proposed for use in the prediction of permanent deformation of geotechnical materials under repetitive loading. The proposed model can be used with numerical tools such as the finite element method with equivalent linear analysis. The degraded secant modulus model with five parameters may employ the parameters of the material models widely accepted in pavement engineering practice to analyse to more general soil problems. The model parameters of the three-parameter model can be estimated based on the results of cyclic triaxial tests or by conducting inverse analysis based on the results of large-scale plate load tests, which are addressed and exemplified in detail in this article. DA - 2014/9/10/ PY - 2014/9/10/ DO - 10.1080/10298436.2014.943208 VL - 16 IS - 6 SP - 549-558 J2 - International Journal of Pavement Engineering LA - en OP - SN - 1029-8436 1477-268X UR - http://dx.doi.org/10.1080/10298436.2014.943208 DB - Crossref KW - subgrade KW - plate load test KW - unbound material KW - permanent deformation KW - numerical analysis ER - TY - CHAP TI - The temporality of Twitter: Considering Chronos and Kairos for digital rhetoric AU - Kelly, A.R. AU - Kittle Autry, M. AU - Mehlenbacher, B. T2 - Digital Rhetoric and Global Literacies: Communication Modes and Digital Practices in the Networked World A2 - Verhulsdonck, G. A2 - Limbu, M. PY - 2014/// SP - 227–247 PB - IGI Global ER - TY - JOUR TI - A Discontinuous Galerkin Coupled Wave Propagation/Circulation Model AU - Meixner, Jessica AU - Dietrich, J. Casey AU - Dawson, Clint AU - Zijlema, Marcel AU - Holthuijsen, Leo H. T2 - Journal of Scientific Computing DA - 2014/// PY - 2014/// DO - 10.1007/s10915-013-9761-5 VL - 59 IS - 2 SP - 334-370 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000334184200003&KeyUID=WOS:000334184200003 KW - Discontinuous Galerkin methods KW - Shallow water equations KW - Action balance equation KW - Coupled model KW - A priori error estimate ER - TY - JOUR TI - Using a Bayesian hierarchical model to improve Lake Erie cyanobacteria bloom forecasts AU - Obenour, Daniel R. AU - Gronewold, Andrew D. AU - Stow, Craig A. AU - Scavia, Donald T2 - Water Resources Research AB - Abstract The last decade has seen a dramatic increase in the size of western Lake Erie cyanobacteria blooms, renewing concerns over phosphorus loading, a common driver of freshwater productivity. However, there is considerable uncertainty in the phosphorus load‐bloom relationship, because of other biophysical factors that influence bloom size, and because the observed bloom size is not necessarily the true bloom size, owing to measurement error. In this study, we address these uncertainties by relating late‐summer bloom observations to spring phosphorus load within a Bayesian modeling framework. This flexible framework allows us to evaluate three different forms of the load‐bloom relationship, each with a particular combination of statistical error distribution and response transformation. We find that a novel implementation of a gamma error distribution, along with an untransformed response, results in a model with relatively high predictive skill and realistic uncertainty characterization, when compared to models based on more common statistical formulations. Our results also underscore the benefits of a hierarchical approach that enables assimilation of multiple sets of bloom observations within the calibration processes, allowing for more thorough uncertainty quantification and explicit differentiation between measurement and model error. Finally, in addition to phosphorus loading, the model includes a temporal trend component indicating that Lake Erie has become increasingly susceptible to large cyanobacteria blooms over the study period (2002–2013). Results suggest that current phosphorus loading targets will be insufficient for reducing the intensity of cyanobacteria blooms to desired levels, so long as the lake remains in a heightened state of bloom susceptibility. DA - 2014/10// PY - 2014/10// DO - 10.1002/2014WR015616 VL - 50 IS - 10 SP - 7847-7860 J2 - Water Resour. Res. LA - en OP - SN - 0043-1397 UR - http://dx.doi.org/10.1002/2014WR015616 DB - Crossref KW - Bayesian hierarchical modeling KW - gamma distribution KW - Lake Erie KW - cyanobacteria KW - phosphorus loading KW - harmful algal blooms ER - TY - CONF TI - Automated Monitoring of Operation-level Construction Progress Using 4D BIM and Daily Site Photologs AU - Han, Kevin K. AU - Golparvar-Fard, Mani AB - Recent research efforts on improving construction progress monitoring have focused mainly on model-based assessment methods. In these methods, the expected performance typically is modeled with 4D BIM, and the actual performance is sensed through the 3D image-based reconstruction method or laser scanning. Previous research on 4D augmented reality (4D AR) models—which fuse 4D BIM with point clouds generated from daily site photologs—and also laser scan versus BIM, have shown that it is possible to conduct occupancy-based assessments, and as an indicator of progress, detect whether BIM elements are present in the scene. However, to detect deviations beyond typical work breakdown structure (WBS) in 4D BIM, these methods also need to capture operation-level details (e.g., current stage of concrete placement: formwork, rebars, concrete). To overcome current limitations, this paper presents methods for sampling and recognizing construction material from image-based point cloud data and using that information in a statistical form to infer the state of progress. The proposed method is validated using the 4D AR model generated for a building construction site. The preliminary experimental results show that it is feasible to sample and detect construction materials from the images that are registered to a point cloud model and use frequency histograms of the detected materials to infer the actual state of progress for BIM elements. C2 - 2014/5// C3 - Construction Research Congress 2014 DA - 2014/5// DO - 10.1061/9780784413517.106 PB - American Society of Civil Engineers ER - TY - CONF TI - Multi-Sample Image-Based Material Recognition and Formalized Sequencing Knowledge for Operation-Level Construction Progress Monitoring AU - Han, Kevin K. AU - Golparvar-Fard, Mani AB - This paper presents a new method for operation-level monitoring of construction progress using image-based 3D point clouds and 4D Building Information Model (BIM). Previous research on comparing point clouds to 4D BIM has proven the practicality of performing progress monitoring by occupancy-based assessment - detecting if BIM elements are present in the scene. Nonetheless, without appearance information, operation-level monitoring - formwork vs. concrete surfaces for concrete placement - is still challenging. By leveraging the interconnectivity of site images and BIM-registered point clouds, this paper presents a new method for densely sampling and extracting 2D patches from all site images from which BIM elements are expected to be visible. Our method reasons about occlusions in the scene and classifies the material in each image patch. By formalizing the sequencing knowledge of construction operations for progress monitoring purposes and using histogram-based representation for possible types of construction materials, our method can accurately detect the current state-of-progress for BIM elements in the presence of occlusions. We introduce a new image dataset for material recognition, and present promising results on operation-level progress monitoring on an actual concrete building construction site. Our method addresses the challenges of working with non-detailed BIM or high-level work breakdown structures. C2 - 2014/6// C3 - Computing in Civil and Building Engineering (2014) DA - 2014/6// DO - 10.1061/9780784413616.046 PB - American Society of Civil Engineers ER - TY - JOUR TI - Using Enhanced Econometric Techniques to Verify the Service Life of Asset Interventions A Case Study for Indiana AU - Bardaka, Eleni AU - Labi, Samuel AU - Haddock, John E. T2 - TRANSPORTATION RESEARCH RECORD AB - In the current era, the highway environment is characterized by funding limitations, aging facilities, and increasing user expectations. In light of these trends, asset managers at most highway agencies have a fiduciary responsibility to apply management strategies and practices that not only are most cost-effective in a life-cycle context but also are in the best interests of taxpayers and highway users. To identify and implement effective rehabilitation strategies and practices, highway agencies need to verify information that was typically based on expert opinion, with reliable asset performance prediction tools and treatment service life estimates. This study provides an enhanced methodology to analyze pavement rehabilitation data and to develop estimates and ranges of treatment service lives. Pavement rehabilitation data typically consist of repeated measurements that form an unbalanced three-level nested structure, making analysis quite challenging. In this study, mixed linear modeling techniques are deployed to accommodate this structure and thus lead to less biased estimations compared with traditionally used approaches. The developed framework is applied to quantify the effectiveness of seven common rehabilitation treatments applied by the Indiana Department of Transportation in regard to their service lives and to validate the treatment service life values presented in the agency's current design manual. DA - 2014/// PY - 2014/// DO - 10.3141/2431-03 VL - 2431 IS - 2431 SP - 16-23 SN - 2169-4052 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84908450724&partnerID=MN8TOARS ER - TY - CONF TI - Uniaxial fatigue testing of diverse asphalt concrete mixtures AU - Zeiada, W.A. AU - Underwood, B.S. AU - Kaloush, K.E. C2 - 2014/// C3 - Proceedings International Conference on Asphalt Pavements DA - 2014/// ER - TY - CONF TI - Techniques for selecting cost-effective pavement rehabilitation strategies: Two case studies AU - Nobakht, M. AU - Sakhaeifar, M.S. AU - Newcomb, D. AU - Underwood, B.S. AU - Freeman, T. C2 - 2014/// C3 - Proceedings 2014 Airfield and Highway Pavements Conference DA - 2014/// ER - TY - CONF TI - Sustainable construction practices AU - Underwood, B.S. AU - El Asmar, M. C2 - 2014/// C3 - 2014 Roads and Streets Conference DA - 2014/// ER - TY - CONF TI - Structuralization as characteristic to link the mechanical behaviors of asphalt concrete at different length scales AU - Underwood, B.S. AU - Kim, Y.R. C2 - 2014/// C3 - Proceedings International Conference on Asphalt Pavements DA - 2014/// ER - TY - CONF TI - Modeling the microdamage healing in asphalt concrete with a smeared continuum damage approach AU - Underwood, B.S. AU - Zeiada, W.A. C2 - 2014/// C3 - 93rd Annual Meeting of the Transportation Research Record DA - 2014/// ER - TY - JOUR TI - Modeling the microdamage healing in asphalt concrete with a smeared continuum damage approach AU - Underwood, B.S. AU - Zeiada, W.A. T2 - Transportation Research Record DA - 2014/// PY - 2014/// SP - 126-135 ER - TY - JOUR TI - Improved method of considering air void and asphalt content changes on long-term performance of asphalt concrete pavements AU - Zeiada, W. A. AU - Kaloush, K. E. AU - Underwood, B. S. AU - Mamlouk, M. E. T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - Mixture properties (aggregate gradation and volumetric quantities), rate of loading and environmental conditions are the most important factors that affect the |E*| values. The main objective of this study was to develop a rational approach to investigate and model the effect of air voids and asphalt content on the |E*| master curves and consequently predict pavement performance. In this study, |E*| tests were conducted on three asphalt concrete mixtures with the same aggregate gradation, but different binder grades. For each of these mixtures, the air void and asphalt contents were varied at three levels. It is found that the developed method provides a more accurate estimate of the effects of volumetric changes in hot mix asphalt. The application of the proposed approach would be most beneficial for quality control/quality assurance purposes, performance-related specifications and for estimating contractors' incentives and penalties, where |E*| is utilised to predict the pavement performance. DA - 2014/9/14/ PY - 2014/9/14/ DO - 10.1080/10298436.2013.857775 VL - 15 IS - 8 SP - 718-730 SN - 1477-268X KW - dynamic modulus (|E*|) KW - air voids KW - asphalt content KW - pavement KW - performance ER - TY - CONF TI - Fibers in pavements AU - Underwood, B.S. C2 - 2014/// C3 - Arizona Pavement/Materials Conference DA - 2014/// ER - TY - CONF TI - Evaluation of methodologies for crossover modulus determination AU - Underwood, B.S. AU - Farrar, M. AU - Hintz, C. AU - Kim, Y.R. C2 - 2014/// C3 - 2014 Petersen Asphalt Research Conference DA - 2014/// ER - TY - CONF TI - Effect of asphalt binder oxidation on the modulus of asphalt concrete mixtures AU - Underwood, B.S. AU - Baek, C.M. AU - Kim, Y.R. C2 - 2014/// C3 - Proceedings International Conference on Asphalt Pavements DA - 2014/// ER - TY - CONF TI - Comparison of hot mix asphalt endurance limit using NCHRP 9-44A developed methodology to other analytical techniques AU - Underwood, B.S. AU - Zeiada, W.A. AU - Kaloush, K. C2 - 2014/// C3 - International Conference on Perpetual Pavement DA - 2014/// ER - TY - JOUR TI - Comparison of fatigue damage, healing, and endurance limit using beam fatigue and uniaxial fatigue tests AU - Zeiada, W.A. AU - Souliman, M. AU - Kaloush, K.E. AU - Mamlouk, M. AU - Underwood, B.S. T2 - Transportation Research Record DA - 2014/// PY - 2014/// SP - 32-41 ER - TY - JOUR TI - Comparison of conventional, polymer, and rubber asphalt mixtures using viscoelastic continuum damage model AU - Zeiada, Waleed A. AU - Underwood, B. Shane AU - Pourshams, Tina AU - Stempihar, Jeffrey AU - Kaloush, Kamil E. T2 - Road Materials and Pavement Design AB - AbstractIn this study, a laboratory experimental programme was conducted to compare the material properties and fatigue performance characteristics for reference, polymer-modified and rubber-modified gap-graded mixtures. These mixtures were placed on E18 highway between the interchanges Järva Krog and Bergshamra in the Stockholm area of Sweden. The advanced material characterisation tests included dynamic (complex) modulus for stiffness evaluation and the uniaxial tension–compression for fatigue assessment. The data were used to compare the performance of the rubber-modified gap-graded mixture to the reference and polymer-modified gap mixtures using the viscoelastic continuum damage (VECD) approach. Different researchers have successfully applied the VECD model to describe the fatigue behaviour of asphalt concrete mixtures. The damage characteristic (C–S) curves were established for each of the three mixtures. The fatigue behaviour for the three mixtures was ranked based on the C–S curve results and the rubber-modified mixture showed the best fatigue damage resistance followed by the polymer-modified and reference mixtures. The VECD approach provides a more comprehensive analysis to evaluate fatigue resistance compared with the traditional fatigue evaluation using a number of cycles at a given stiffness reduction.Keywords: fatiguerubber-modifiedpolymer-modifieddynamic modulusviscoelastic continuum damage DA - 2014/5/8/ PY - 2014/5/8/ DO - 10.1080/14680629.2014.914965 VL - 15 IS - 3 SP - 588-605 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2014.914965 DB - Crossref KW - fatigue KW - rubber-modified KW - polymer-modified KW - dynamic modulus KW - viscoelastic continuum damage ER - TY - JOUR TI - Continuous Self-Healing Life Cycle in Vascularized Structural Composites AU - Patrick, Jason F. AU - Hart, Kevin R. AU - Krull, Brett P. AU - Diesendruck, Charles E. AU - Moore, Jeffrey S. AU - White, Scott R. AU - Sottos, Nancy R. T2 - ADVANCED MATERIALS AB - By incorporating 3D microvascular networks containing a two-part reactive chemistry within a fiber-reinforced composite, continuous cycles of self-healing after interlaminar delamination are achieved. An interpenetrating vasculature shows improved in situ fluid mixing over segregated microchannels, resulting in full recovery (>100%) of mode-I fracture resistance. DA - 2014/7/2/ PY - 2014/7/2/ DO - 10.1002/adma.201400248 VL - 26 IS - 25 SP - 4302-4308 SN - 1521-4095 ER - TY - JOUR TI - Simulating smoke transport from wildland fires with a regional-scale air quality model: Sensitivity to spatiotemporal allocation of fire emissions AU - Garcia-Menendez, Fernando AU - Hu, Yongtao AU - Odman, Mehmet T. T2 - Science of The Total Environment AB - Air quality forecasts generated with chemical transport models can provide valuable information about the potential impacts of fires on pollutant levels. However, significant uncertainties are associated with fire-related emission estimates as well as their distribution on gridded modeling domains. In this study, we explore the sensitivity of fine particulate matter concentrations predicted by a regional-scale air quality model to the spatial and temporal allocation of fire emissions. The assessment was completed by simulating a fire-related smoke episode in which air quality throughout the Atlanta metropolitan area was affected on February 28, 2007. Sensitivity analyses were carried out to evaluate the significance of emission distribution among the model's vertical layers, along the horizontal plane, and into hourly inputs. Predicted PM2.5 concentrations were highly sensitive to emission injection altitude relative to planetary boundary layer height. Simulations were also responsive to the horizontal allocation of fire emissions and their distribution into single or multiple grid cells. Additionally, modeled concentrations were greatly sensitive to the temporal distribution of fire-related emissions. The analyses demonstrate that, in addition to adequate estimates of emitted mass, successfully modeling the impacts of fires on air quality depends on an accurate spatiotemporal allocation of emissions. DA - 2014/9// PY - 2014/9// DO - 10.1016/j.scitotenv.2014.05.108 VL - 493 SP - 544-553 J2 - Science of The Total Environment LA - en OP - SN - 0048-9697 UR - http://dx.doi.org/10.1016/j.scitotenv.2014.05.108 DB - Crossref KW - CMAQ KW - Air quality KW - Fire emissions KW - PM2.5 KW - Sensitivity analysis KW - Modeling ER - TY - CONF TI - Fatigue and ratcheting experimental responses of alloy 617 under high temperature multiaxial loading AU - Quayyum, S. AU - Sengupta, M. AU - Choi, G. AU - Lissenden, C. J. AU - Hassan, T. AB - Nickel based Alloy 617 is one of the leading candidate materials for intermediate heat exchanger (IHX) of the next generation nuclear plant (NGNP). The IHX is anticipated to operate at temperatures between 800–950°C, which is in the creep regime. In addition, system start-ups and shut-downs will induce low cycle fatigue (LCF) damages in the IHX components. Hence, designing IHX using Alloy 617 for NGNP construction will require a detailed understanding of the creep-fatigue and ratcheting responses. In this study, a broad set of multiaxial creep-fatigue and ratcheting experiments are performed and the results are critically evaluated. Experiments are conducted by prescribing multiaxial loading histories in axial and shear directions at 850°C and 950°C with different strain rates and strain amplitudes. Experimental results revealed that the axial strain ratcheting and cyclic hardening/softening responses of Alloy 617 vary significantly with temperature levels, strain rates and strain amplitudes indicating the dependence of creep-fatigue and ratcheting responses on these parameters. This necessitates the incorporation of strain rate and strain amplitude dependence and effect of loading non-proportionality and temperature in the unified constitutive modeling (UCM) for a better prediction of the material behavior. Development of a UCM is underway based on the experimental results developed. C2 - 2014/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference - 2013, vol 3: Design and Analysis DA - 2014/// DO - 10.1115/pvp2013-97252 ER - TY - CONF TI - Evaluation of plate anchors capacity in saturated soils using different constitutive models AU - Aghazadeh, Z. AU - Rahman, M. S. AU - Gabr, Mohammed AB - Evaluation of the uplift capacity of plate anchors in saturated clay is an important aspect in offshore anchoring of various structures. In most of the literature reviewed, a constitutive model such as Tresca or Mohr-Coulomb has been used in analyses. There exists a need to study the anchors’ pull out capacity using other advanced soil models and discern differences in results. This study presents the results of finite element simulation of a rectangular or circular plate anchor in saturated clay. The capacity factors (Nc) of the plate are assessed through the application of displacement control approach and the results are compared to the lower bound solution as well as to data obtained from similar studies available in the literature. In addition to Mohr-Coulomb model, two other constitutive models are used to represent the soil deformation. These are Modified Cam-Clay, and Soft Soil models. Undrained effective stress analyses are conducted using the computer program PLAXIS. A series of analyses using different embedment depths are performed for all three constitutive models. Results as Nq value from the three constitutive models are presented and discussed. C2 - 2014/// C3 - 33rd International Conference on Ocean, Offshore and Arctic Engineering, 2014, vol 3 DA - 2014/// DO - 10.1115/omae2014-24226 ER - TY - CONF TI - Constitutive modeling of high temperature uniaxial creep-fatigue and creep-ratcheting responses of alloy 617 AU - Pritchard, P. G. AU - Carroll, L. AU - Hassan, T. AB - Inconel Alloy 617 is a high temperature creep and corrosion resistant alloy and is a leading candidate for use in Intermediate Heat Exchangers (IHX) of the Next Generation Nuclear Plants (NGNP). The IHX of the NGNP is expected to experience operating temperatures in the range of 800°–950°C, which is in the creep regime of Alloy 617. A broad set of uniaxial, low-cycle fatigue, fatigue-creep, ratcheting, and ratcheting-creep experiments are conducted in order to study the fatigue and ratcheting responses, and their interactions with the creep response at high temperatures. A unified constitutive model developed at North Carolina State University is used to simulate these experimental responses. The model is developed based on the Chaboche viscoplastic model framework. It includes cyclic hardening/softening, strain rate dependence, strain range dependence, static and dynamic recovery modeling features. For simulation of the alloy 617 responses, new techniques of model parameter determination are developed for optimized simulations. This paper compares the experimental responses and model simulations for demonstrating the strengths and shortcomings of the model. C2 - 2014/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference - 2013, vol 5 DA - 2014/// DO - 10.1115/pvp2013-97251 ER - TY - CONF TI - Constitutive modeling of Haynes 230 for anisothermal thermo-mechanical fatigue and multiaxial creep-ratcheting responses AU - Ahmed, R. AU - Barrett, P. R. AU - Hassan, T. AB - Service life analysis and design of high temperature components, such as turbine engines, needs accurate estimation of stresses and strains at failure locations. The structural integrity under these high temperature environments can be evaluated through finite element structural analysis. This requires a robust constitutive model to predict local stresses and strains. A unified viscoplastic constitutive model based on the Chaboche type nonlinear kinematic hardening rule was developed including the added features of strain range dependence, rate dependence, temperature dependence, static recovery, and a mean stress evolution. The new constitutive model was validated through critical evaluation of the simulation of a broad set of stress and strain responses of a nickel-base superalloy Haynes 230. The experimental database encompasses uniaxial strain-controlled loading histories which include isothermal low cycle creep-fatigue and anisothermal thermo-mechanical fatigue experiments at temperatures ranging from 75°F to 1800°F. Simulations from the modified model are presented to demonstrate its strengths and weaknesses, and future work is needed for developing a robust constitutive model. C2 - 2014/// C3 - Proceedings of the ASME Pressure Vessels and Piping Conference - 2013, vol 6B: Materials and Fabrication DA - 2014/// DO - 10.1115/pvp2013-97248 ER - TY - CONF TI - Scour Zone Characterization by Deep Impinging Jet AU - Kebede, Yulian A. AU - Gabr, Mohammed A. AU - Kayser, Mohammad F. AB - Scour downstream of many hydraulic structures such as culverts and spillways may be treated as analogues to jet scour. This study presents the characterization of a fluidized zone by an impinging jet using a recently developed In Situ Erosion Evaluation Probe (ISEEP). Jet embedment was varied from 0.61 m (2 ft) to 2.43 m (8 ft) in the laboratory with a jet velocity ranging from 3 m/s to 6 m/s using an external pump. A number of piezometers were installed radially and with depth around the probe to characterize the extent of the fluidized zone (zone where effective stress reaches zero). Results indicated that the shape of the embedded fluidized zone changes from spherical to elliptical with increasing impinging distance. The nature of the zone expansion was categorized into three phases: initial, transition, and steady state. A jet velocity of 3.8 m/s resulted in a lateral distance of the fluidization zone that extended 0.3 m from the probe. At jet velocities of 4.2 m/s and 4.5 m/s, the lateral distance of the fluidization zone reached about 0.40 m and 0.45 m, respectively. Vertically, a jet velocity of 4.2 m/s fluidized the soil up to 0.3 m above the jet (probe tip) at 2.4 m embedment depth. At an embedment depth of 2.4 m, this maximum fluidization zone occurs as a closed fluidization. The dimensions of this zone are a function of the applied jet velocity (considering the values used in this study). C2 - 2014/6/8/ C3 - Volume 8B: Ocean Engineering DA - 2014/6/8/ DO - 10.1115/omae2014-24257 PB - ASME International ER - TY - CONF TI - Preliminary Structural Design of OCAES Vessel AU - Xiao, Jinfu AU - Gabr, M. AU - Rahman, M. S. AB - A vessel for Offshore Compressed Air Energy Storage (OCAES) is being considered as a part of the emerging technology to store intermittently generated energy from offshore renewable sources. The basic idea is to submerge the storage vessel into the ocean at a large water depth, convert the energy into compressed air, store it with using the hydrostatic water pressure to balance the compressed air pressure without requiring the storage vessels to resist high internal air pressure. An additional advantage is that the interface of air and water acts as a piston to maintain the air pressure level. In this study, a rectangular configuration and a cylindrical configuration are proposed for the OCEAS vessel. Stress controlled analyses are performed for the preliminary design of the OCAES vessel with emphasis on characterization of applied cyclic load induced by the air/water exchange in the inflation/deflation process. The stress distribution and deformation pattern in the OCAES vessel at different loading stages are studied by using the multi-physics FEM program COMSOL. Key parameters including storage volume, geometry of OCAES vessel, and material selection are discussed. C2 - 2014/6/8/ C3 - Volume 9B: Ocean Renewable Energy DA - 2014/6/8/ DO - 10.1115/omae2014-24053 PB - ASME International ER - TY - BOOK TI - Asphalt pavements DA - 2014/// PY - 2014/// PB - Boca Raton: CRC Press ER - TY - JOUR TI - Performance Predictions of Rutting for the National Center for Asphalt Technology Test Track AU - Lacroix, Andrew AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Performance-related specifications base pay rates on tests that measure and predict the performance of the mixture. This study evaluated several methods for predicting the rutting resistance of asphalt mixtures. The mixtures and field performance data came from the National Center for Asphalt Technology test track. The pavement sections evaluated were part of an experiment that focused on warm-mix asphalt, high-content reclaimed asphalt pavement (50%), and a combination of the two. One method involved using the dynamic moduli of the mixtures in confined and unconfined conditions. The ranking of the mixtures predicted from both conditions was good compared with the observed ranking from the track but was more reasonable with the confined data. These predictions were compared with common current tests such as the asphalt pavement analyzer and the Hamburg wheel tracker tests. From the ranking of rut depths, these tests did not appear able to distinguish subtler changes to material properties needed for a performance-related specification. Another method employed a viscoplastic shift model implemented within the layered viscoelastic continuum damage program to predict the rut depth. The predicted rut depths were biased 2.5 mm higher than those measured in the field when all three layers (175 mm) of asphalt were used to predict the rut depth, but the ranking matched the field quite well. The results from the top two layers (100 mm) of asphalt were less biased but were more variable than the three-layer results. The results suggest that all pavement layers should be evaluated for predicting rut depths, not just the top two layers. DA - 2014/// PY - 2014/// DO - 10.3141/2457-05 IS - 2457 SP - 41-50 SN - 2169-4052 ER - TY - CONF TI - The reflective cracking tester: A third-scale accelerated pavement tester for reflective cracking AU - Wargo, A. D. AU - Islam, S. AU - Kim, Y. R. C2 - 2014/// C3 - Asphalt Pavements, vols 1 and 2 DA - 2014/// SP - 1685-1693 ER - TY - JOUR TI - New Algorithms for Computing the Time-to-Collision in Freeway Traffic Simulation Models AU - Hou, Jia AU - List, George F. AU - Guo, Xiucheng T2 - COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE AB - Ways to estimate the time-to-collision are explored. In the context of traffic simulation models, classical lane-based notions of vehicle location are relaxed and new, fast, and efficient algorithms are examined. With trajectory conflicts being the main focus, computational procedures are explored which use a two-dimensional coordinate system to track the vehicle trajectories and assess conflicts. Vector-based kinematic variables are used to support the calculations. Algorithms based on boxes, circles, and ellipses are considered. Their performance is evaluated in the context of computational complexity and solution time. Results from these analyses suggest promise for effective and efficient analyses. A combined computation process is found to be very effective. DA - 2014/// PY - 2014/// DO - 10.1155/2014/761047 VL - 2014 SP - SN - 1687-5273 ER - TY - JOUR TI - Microbial Power-Generating Capabilities on Micro-/Nano-Structured Anodes in Micro-SizedMicrobial Fuel Cells AU - Fraiwan, A. AU - Adusumilli, S. P. AU - Han, D. AU - Steckl, A. J. AU - Call, D. F. AU - Westgate, C. R. AU - Choi, S. T2 - FUEL CELLS AB - Abstract Microbial fuel cells (MFCs) are an alternative electricity generating technology and efficient method for removing organic material from wastewater. Their low power densities, however, hinder practical applications. A primary limitation in these systems is the anode. The chemical makeup and surface area of the anode influences bacterial respiration rates and in turn, electricity generation. Some of the highest power densities have been reported using large surface area anodes, but due to variable chemical/physical factors (e.g., solution chemistry, architecture) among these studies, meaningful comparisons are difficult to make. In this work, we compare under identical conditions six micro/nano‐structured anodes in micro‐sized MFCs (47 μL). The six materials investigated include carbon nanotube (CNT), carbon nanofiber (CNF), gold/poly (ϵ‐caprolactone) microfiber (GPM), gold/poly(ϵ‐caprolactone) nanofiber (GPN), planar gold (PG), and conventional carbon paper (CP). The MFCs using three dimensional anode structures (CNT, CNF, GPM, and GPN) exhibited lower internal resistances than the macroscopic CP and two‐dimensional PG anodes. However, those novel anode materials suffered from major issues such as high activation loss and instability for long‐term operation, causing an enduring problem in creating widespread commercial MFC applications. The reported work provides an in‐depth understanding of the interplay between micro‐/nano‐structured anodes and active microbial biofilm, suggesting future directions of those novel anode materials for MFC technologies. DA - 2014/12// PY - 2014/12// DO - 10.1002/fuce.201400041 VL - 14 IS - 6 SP - 801-809 SN - 1615-6854 KW - Biofilm Formation KW - Extracellular Electron Transfer KW - Mass Transfer KW - Micro-/Nano-Structured Anode Materials KW - Microbial Fuel Cell ER - TY - JOUR TI - Method for scenario selection and probability adjustment for reliability and active traffic management analysis in a highway capacity manual context AU - Aghdashi, S. AU - Schroeder, B. J. AU - Rouphail, N. M. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2461 SP - 58-65 ER - TY - JOUR TI - Lane utilization at two-lane arterial approaches to double crossover diamond interchanges AU - Yeom, C. AU - Schroeder, B. J. AU - Cunningham, C. AU - Vaughan, C. AU - Rouphail, N. M. AU - Hummer, J. E. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2461 SP - 103-112 ER - TY - CONF TI - Investigation of the effect of temperature on asphalt binder fatigue AU - Safaei, F. AU - Hintz, C. C2 - 2014/// C3 - Asphalt Pavements, vols 1 and 2 DA - 2014/// DO - 10.1201/b17219-181 SP - 1491–1500 ER - TY - JOUR TI - Importance of Normal Confinement to Shear Bond Failure of Interface in Multi layer Asphalt Pavements AU - Karshenas, Afshin AU - Cho, Seong-Hwan AU - Tayebali, Akhtarhusein A. AU - Guddati, Murthy N. AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - Several direct shear test devices are used to evaluate the shear bond strength of tack coat materials in interlayer bonding in asphalt pavements. Some devices have the capability of evaluating strength in direct shear with normal confinement, whereas other devices do not have that capability or use passive confinement to evaluate the interlayer bond strength. The literature indicates that interlayer bond strength increases with the application of normal confinement. However, the question remains as to the level of normal confinement, if any, that should be used in direct shear testing to evaluate the interlayer bond strength for specification acceptance or design. This study presents a methodology to interpret laboratory bond strength test results in relation to the state of stress at the layer interface in a representative pavement section. The results confirm the importance of normal confinement for shear bond strength evaluation and provide guidance for the selection of the appropriate level of normal ... DA - 2014/// PY - 2014/// DO - 10.3141/2456-17 IS - 2456 SP - 170-177 SN - 2169-4052 ER - TY - JOUR TI - Task Variation and the Social Network of Construction Trades AU - Wambeke, Brad W. AU - Liu, Min AU - Hsiang, Simon M. T2 - Journal of Management in Engineering AB - Construction projects can be complex and managers are faced with the challenge of managing multiple trades working on a large number of interdependent tasks. When one trade or task experiences variation, defined as the time difference between what was planned and what occurred for this research, additional trades or tasks can be impacted. This can result in a disrupted project schedule and reduced productivity. A case study involving a general contractor (GC) building a $50 million, 150,000 sq ft data collection center was conducted. Both starting time and task duration variation data was collected on approximately 1,200 tasks performed by over 40 trades. A risk assessment matrix was used to determine which causes of variation posed the greatest risk to project performance. Pajek, a social network analysis software, was used to illustrate the organizational structure of the key trades throughout the project based on spatial proximity. It was found that material delivery and not having prerequisite work completed were the top two causes of starting time variation and overcommitment was the top cause of task duration variation. The study couples the variation analysis with the associated social network of trades to create a decision making system, thus, the paper’s main contribution to the body of knowledge. The results of this research are repeatable and can be useful for managers in improving project performance. DA - 2014/7// PY - 2014/7// DO - 10.1061/(asce)me.1943-5479.0000219 VL - 30 IS - 4 SP - 05014008 J2 - J. Manage. Eng. LA - en OP - SN - 0742-597X 1943-5479 UR - http://dx.doi.org/10.1061/(asce)me.1943-5479.0000219 DB - Crossref KW - Variation KW - Risk assessment KW - Social network KW - Performance KW - Construction ER - TY - JOUR TI - Geobacter sp SD-1 with enhanced electrochemical activity in high-salt concentration solutions AU - Sun, Dan AU - Call, Douglas AU - Wang, Aijie AU - Cheng, Shaoan AU - Logan, Bruce E. T2 - ENVIRONMENTAL MICROBIOLOGY REPORTS AB - Summary An isolate, designated strain SD ‐1, was obtained from a biofilm dominated by G eobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD ‐1 was compared with type strains, G . sulfurreducens PCA and G eobacter metallireducens GS ‐15, and a mixed culture in microbial electrolysis cells. SD‐1 produced a maximum current density of 290 ± 29 A m −3 in a high‐concentration phosphate buffer solution ( PBS ‐ H , 200 mM). This current density was significantly higher than that produced by the mixed culture (189 ± 44 A m −3 ) or the type strains (< 70 A m −3 ). In a highly saline water ( SW ; 50 mM PBS and 650 mM NaCl ), current by SD ‐1 (158 ± 4 A m −3 ) was reduced by 28% compared with 50 mM PBS (220 ± 4 A m −3 ), but it was still higher than that of the mixed culture (147 ± 19 A m −3 ), and strains PCA and GS ‐15 did not produce any current. Electrochemical tests showed that the improved performance of SD ‐1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD ‐1 was significantly different than other G eobacter strains and mixed cultures in terms of its salt tolerance. DA - 2014/12// PY - 2014/12// DO - 10.1111/1758-2229.12193 VL - 6 IS - 6 SP - 723-729 SN - 1758-2229 ER - TY - CONF TI - Evaluation of warm mix asphalt technology for surface mixtures AU - Ayyala, D. AU - Malladi, H. AU - Khosla, N. P. AU - Tayebali, A. A. AB - Economic, environmental, and engineering benefits led to the rapid implementation of Warm-Mix Asphalt (WMA) during the past decade. While WMA technologies are generally performing well to date, development of standard mix design protocols continues and performance questions remain. This study evaluated laboratory conditioning protocols for WMA to simulate early life when they are more moisture susceptible and proposed 2 hours at 116°C for mix design and reheating to this temperature for quality assurance for all WMA technologies except foaming which requires reheating to 135°C. Next, WMA was shown to be more moisture susceptible as compared to Hot-Mix Asphalt in the early life based on a comprehensive analysis of three standard laboratory tests (wet and dry indirect tensile strengths and resilient modulus and their ratios and Hamburg Wheel Tracking Test stripping parameters) from four field projects that included nine WMA mixtures. Finally, an evaluation of performance evolution showed that WMA can overcome this vulnerability to moisture after a summer of aging and proposed 5 days oven aging at 85°C to capture this effect in the laboratory. Proposed conditioning protocols, aging protocols, and criteria for the tests utilized are provided for WMA mix design and analysis to preclude moisture susceptibility. C2 - 2014/// C3 - Asphalt Pavements, vol 1 DA - 2014/// DO - 10.1201/b17219-88 SP - 701-708 ER - TY - CONF TI - Evaluation of early aggregate retention performance of chip seals with polymer-modified emulsions AU - Im, J. H. AU - Kim, Y. R. C2 - 2014/// C3 - Asphalt Pavements, vol 1 DA - 2014/// DO - 10.1201/b17219-20 SP - 105-114 ER - TY - JOUR TI - Decomposition of Sources of Errors in Monthly to Seasonal Streamflow Forecasts in a Rainfall-Runoff Regime AU - Sinha, Tushar AU - Sankarasubramanian, A. AU - Mazrooei, Amirhossein T2 - JOURNAL OF HYDROMETEOROLOGY AB - Abstract Despite considerable progress in developing real-time climate forecasts, most studies have evaluated the potential in seasonal streamflow forecasting based on ensemble streamflow prediction (ESP) methods, utilizing only climatological forcings while ignoring general circulation model (GCM)-based climate forecasts. The primary limitation in using GCM forecasts is their coarse resolution, which requires spatiotemporal downscaling to implement land surface models. Consequently, multiple sources of errors are introduced in developing real-time streamflow forecasts utilizing GCM forecasts. A set of error decomposition metrics is provided to address the following questions: 1) How are errors in monthly streamflow forecasts attributed to various sources such as temporal disaggregation, spatial downscaling, imprecise initial hydrologic conditions (IHCs), climatological forcings, and imprecise forecasts? and 2) How do these errors propagate with lead time over different seasons? A calibrated Variable Infiltration Capacity model is used over the Apalachicola River at Chattahoochee in the southeastern United States. The model is forced with a combination of daily precipitation forcings (temporally disaggregated observed precipitation, spatially downscaled and temporally disaggregated observed precipitation, ESP, ECHAM4.5 forecasts, and observed) and IHCs [simulated and climatological ensemble reverse ESP (RESP)] but with observed air temperature and wind speed at ⅛° resolution. Then, errors in forecasting monthly streamflow at up to a 3-month lead time are decomposed by comparing the forecasted streamflow to simulated streamflow under observed forcings. Results indicate that the errors due to temporal disaggregation are much higher than the spatial downscaling errors. During winter and early spring, the increasing order of errors at a 1-month lead time is spatial downscaling, model, temporal disaggregation, RESP, large-scale precipitation forecasts, and ESP. DA - 2014/12// PY - 2014/12// DO - 10.1175/jhm-d-13-0155.1 VL - 15 IS - 6 SP - 2470-2483 SN - 1525-7541 KW - Hydrology KW - Forecasting KW - Hindcasts KW - Seasonal forecasting KW - Model errors ER - TY - JOUR TI - Biaxial Ratcheting of Ultra High Molecular Weight Polyethylene: Experiments and Constitutive Modeling AU - Asmaz, Kerem AU - Colak, Ozgenu U. AU - Hassan, Tasnim T2 - JOURNAL OF TESTING AND EVALUATION AB - Responses of ultra-high molecular weight polyethylene (UHMWPE) under biaxial cyclic loading were investigated through systematically conducting experiments. Biaxial experiments on UHMWPE tubular specimens were conducted first by prescribing a steady internal pressure followed by a symmetric axial-strain controlled cycle. The steady internal pressure induced a steady nominal circumferential stress, which under the application of the axial strain-controlled cycle, induced circumferential strain ratcheting in the UHMWPE tubular specimens. Experimentally observed ratcheting responses of UHMWPE under biaxial cyclic loading was simulated using one of the unified state variable theories, the viscoplasticity theory based on overstress for polymers (VBOP). To improve the circumferential strain ratcheting simulation of the VBOP model, the Chaboche kinematic hardening rule was implemented in the model. The simulation of the VBOP model with the classical kinematic hardening model was also carried out to demonstrate the current state of the modeling for UHMWPE. Improvement of the circumferential strain ratcheting simulation by the modified VBOP model is demonstrated; however, simulations also indicate that further model modification will be needed. DA - 2014/11// PY - 2014/11// DO - 10.1520/jte20130131 VL - 42 IS - 6 SP - 1486-1492 SN - 1945-7553 KW - UHMWPE KW - biaxial experiment KW - biaxial ratcheting KW - viscoplastic modeling KW - multiaxial modeling ER - TY - JOUR TI - Performance-Based Moisture Susceptibility Evaluation of Warm-Mix Asphalt Concrete Through Laboratory Tests AU - Lee, Jong-Sub AU - Kim, Y. Richard T2 - TRANSPORTATION RESEARCH RECORD AB - This study used the cyclic direct tension test, indirect tensile strength test, and Hamburg wheel tracking device (HWTD) test to evaluate the moisture susceptibility of warm-mix asphalt (WMA) mixtures. The stripped areas that were quantified by digital imaging analysis were derived from the cyclic direct tension, indirect tensile strength, and HWTD tests and were compared with the mechanical properties of the mixtures to identify sensitive moisture susceptibility indicators. These methods were applied to a Superpave® 9.5-mm hot-mix asphalt mixture and five corresponding WMA mixtures that used the following technologies: (a) Evotherm 3G that contained a chemical additive, (b) foaming, (c) WMA-A that contained a chemical additive and was under development, (d) WMA-B that contained an organic additive and was under development, and (e) WMA-C that also contained an organic additive (different from that used in WMA-B) and was under development. Fatigue life ratios obtained from the simplified viscoelastic continuum damage model combined with layered viscoelastic analyses were determined to be the most sensitive indicators for moisture susceptibility. The stripping infection points derived from the HWTD tests also showed good sensitivity to moisture conditioning; however, each stripping infection point was affected by the permanent deformation characteristics of a given mixture as well as its moisture susceptibility; therefore, the observation was inconclusive. DA - 2014/// PY - 2014/// DO - 10.3141/2446-03 IS - 2446 SP - 17-28 SN - 2169-4052 ER - TY - JOUR TI - Development of a failure criterion for asphalt mixtures under different modes of fatigue loading AU - Sabouri, M. AU - Kim, Y. R. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2447 SP - 117-125 ER - TY - JOUR TI - Considerations for Effective Lidar Deployment by Transportation Agencies AU - Chang, Jeffrey C. AU - Findley, Daniel J. AU - Cunningham, Christopher M. AU - Tsai, Mary K. T2 - TRANSPORTATION RESEARCH RECORD AB - Lidar is becoming increasingly popular across the United States, and state transportation agencies are adopting this technology for practical uses in transportation-related applications. This trend can be seen in the growing number of agencies acquiring lidar scanners and contracting lidar services. The primary factors behind this trend are that (a) surveyors, engineers, and technicians are becoming more educated about and increasingly open to lidar and its applications and (b) lidar is potentially more cost-effective than traditional surveying technologies. Lidar can provide transportation agencies with the benefits of safety, data collection productivity, cost-effectiveness, applicability, high levels of detail, and technological advancement. Many of the more practical uses and benefits of lidar have come to fruition in recent years, and transportation agencies have been more open to its use. However, little more than anecdotal evidence supports when a specific lidar platform should be applied for various applications rather than a traditional surveying method. Decision makers in geomatic and surveying departments that use lidar must regularly weigh the options of which surveying method to use for specific projects and base decisions on performance tradeoffs. The methodology presented in this paper aims to provide guidance on how agencies may determine whether lidar can be practically used within their organizations. The aspects and performance measures outlined for effective deployment of lidar equipment or contracted services should be systematically considered. DA - 2014/// PY - 2014/// DO - 10.3141/2440-01 IS - 2440 SP - 1-8 SN - 2169-4052 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000348890600001&KeyUID=WOS:000348890600001 ER - TY - JOUR TI - Assessment of the Effect of Population and Diary Sampling Methods on Estimation of School-Age Children Exposure to Fine Particles AU - Che, W. W. AU - Frey, H. Christopher AU - Lau, Alexis K. H. T2 - RISK ANALYSIS AB - Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified‐random and random‐random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov‐chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM 2.5 ) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m 3 for simulated children using the stratified population sampling method, and 12.2 μg/m 3 using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m 3 due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern. DA - 2014/12// PY - 2014/12// DO - 10.1111/risa.12238 VL - 34 IS - 12 SP - 2066-2079 SN - 1539-6924 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84921063491&partnerID=MN8TOARS KW - Children KW - exposure KW - microenvironment KW - modeling KW - particulate matter KW - variability ER - TY - JOUR TI - Structural integrity affects nitrogen removal activity of granules in semi-continuous reactors AU - Mota, Cesar R. AU - Head, Melanie A. AU - Williams, Jon C. AU - Eland, Lucy AU - Cheng, Jay J. AU - Reyes, Francis L., III T2 - BIODEGRADATION DA - 2014/11// PY - 2014/11// DO - 10.1007/s10532-014-9712-3 VL - 25 IS - 6 SP - 923-934 SN - 1572-9729 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84907062953&partnerID=MN8TOARS KW - Fluorescence in situ hybridization KW - Aerobic granules KW - Structure KW - Flocs KW - Nitrification KW - Denitrification KW - Particle size ER - TY - JOUR TI - Quantitative Analysis of Curing Mechanisms of Epoxy Resin by Mid- and Near-Fourier Transform Infra Red Spectroscopy AU - Cholake, Sagar T. AU - Mada, Mykanth R. AU - Raman, R. K. Singh AU - Bai, Yu AU - Zhao, X. L. AU - Rizkalla, Sami AU - Bandyopadhyay, Sri T2 - DEFENCE SCIENCE JOURNAL AB - This article informs the essence of major work done by a number of researchers on the analysis of two-step curing mechanism of diglycidyl ether of bisphenol A (DGEBA) epoxy resin in presence of amine curing agents using near- and mid-IR technology. Various peaks used as a marker for resin formation are discussed and their implementation is comprehensively studied. In addition to this, a wide range of information about the importance of reference peaks in both near-IR (NIR) and mid-IR (MIR) regions are congregated and their accuracy is audited. Also discrepancies observed by researchers in epoxy conversion (α) in NIR and MIR regions are reviewed to highlight the comparative advantages of both regions, one over the other. Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 314-321, DOI:http://dx.doi.org/10.14429/dsj.64.7326 DA - 2014/5// PY - 2014/5// DO - 10.14429/dsj.64.7326 VL - 64 IS - 3 SP - 314-321 SN - 0976-464X KW - Epoxy resin KW - amines KW - FTIR KW - curing ER - TY - JOUR TI - Psychological Antecedents of Risk-Taking Behavior in Construction AU - Tixier, Antoine J. -P. AU - Hallowell, Matthew R. AU - Albert, Alex AU - Boven, Leaf AU - Kleiner, Brian M. T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Despite strong advancements in construction safety performance over the past few decades, injuries still occur at an unacceptable rate. Researchers have shown that risk-taking behavior, originating mainly from inaccurate perception and unacceptable tolerance of safety risk, is a significant factor in a majority of construction injuries. Based on psychology research that suggests cognitive interactions between emotions and risk perception, the hypothesis was formed that there are objectively measureable differences in construction safety risk perception between people in different emotional states. To test this hypothesis, a controlled experiment was designed and conducted that (1) induced various positive and negative emotions in 69 subjects using validated movie excerpts; (2) measured emotional states using a validated post-film questionnaire; (3) exposed participants to construction hazards within a high fidelity virtual environment; and (4) measured subjects’ perceptions of the risk related to these hazards adopting a validated frequency-severity-based questionnaire. Once these data were collected, a principal component analysis (PCA) was performed to identify uncorrelated groups of related emotions. A Kruskal-Wallis test followed by multiple Mann-Whitney U tests was then used to test for differences in risk perception between participants belonging to these different emotional groups. The results of these analyses indicated that the mild negative group (sad and unhappy subjects) and the intense negative group (fearful, anxious, and disgusted subjects) perceived statistically significantly (p=0.003) more risk than the positive group (happy, amused, joyful, and interested subjects). The two negative groups were also found to perceive more risk than the neutral group (p<0.02). However, no statistically significant difference in risk perception was found between the positive and neutral groups or between the two negative groups. According to situational awareness literature, the implication of these findings is that individuals in positive and neutral emotional states may be more prone to engage in risk-taking behaviors than their counterparts because they perceive less risk in the same environment. DA - 2014/11// PY - 2014/11// DO - 10.1061/(asce)co.1943-7862.0000894 VL - 140 IS - 11 SP - SN - 1943-7862 KW - Safety KW - Emotions KW - Risk taking KW - Risk KW - Labor and personnel issues ER - TY - JOUR TI - Performance evaluation of different repair concretes proposed for an existing deteriorated jetty structure AU - Ghasemzadeh, F. AU - Sajedi, S. AU - Shekarchi, M. AU - Layssi, H. AU - Hallaji, M. T2 - Journal of Performance of Constructed Facilities DA - 2014/// PY - 2014/// VL - 28 IS - 4 ER - TY - JOUR TI - Nano-mechanical properties of internally cured kenaf fiber reinforced concrete using nanoindentation AU - Zadeh, Vahid Zanjani AU - Bobko, Christopher P. T2 - CEMENT & CONCRETE COMPOSITES AB - Kenaf fiber reinforced concrete (KFRC) is being considered as a more sustainable fiber reinforced concrete. The effect of water-absorbing kenaf fibers on the microstructure of concrete was studied using nanoindentation. Results showed that cement hydration products found in KFRC are similar to those in conventional concrete, but relative volume fractions of these hydration products differ in KFRC. KFRC samples have more CH/CSH and less LD CSH in bulk than would be expected for plain concretes with similar water–cement ratios. Further nanoindentation experiments were performed in the interfacial transition zones around individual kenaf fibers, revealing a porous phase, a high percentage of LD CSH, and a lack of HD CSH in the fiber interfacial zones. The water absorbance of kenaf fibers and associated internal curing effects explain both results. Enhanced production of higher density hydration products in KFRC may provide a pathway for optimal design of these materials. DA - 2014/9// PY - 2014/9// DO - 10.1016/j.cemconcomp.2014.04.002 VL - 52 SP - 9-17 SN - 1873-393X KW - Hydration products KW - Interfacial transition zone KW - Microstructure KW - Mechanical properties KW - Internal curing ER - TY - JOUR TI - Modeling the impact of subject and opponent vehicles on crash severity in two-vehicle collisions AU - Tarrao, G. A. AU - Coelho, M. C. AU - Rouphail, N. M. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2432 SP - 53-64 ER - TY - JOUR TI - Modeling a continuous flow ultraviolet Light Emitting Diode reactor using computational fluid dynamics AU - Jenny, Richard M. AU - Simmons, Otto D., III AU - Shatalov, Max AU - Ducoste, Joel J. T2 - CHEMICAL ENGINEERING SCIENCE AB - The use of ultraviolet (UV) light for water treatment disinfection has become increasingly popular due to its ability to inactivate chlorine-resistant microorganisms without the production of known disinfection by-products. Currently, mercury-based lamps are the most commonly used UV disinfection source; however, these lamps are toxic if broken during installation or by foreign object strike during normal operation. In addition, disposal of degraded, hazardous mercury lamps can be challenging in rural and developing countries for point-of-use (POU) drinking water disinfection applications. UV Light Emitting Diodes (LEDs) offer an alternative, non-toxic UV source that will provide design flexibility due to their small size, longer operating life, and fewer auxiliary electronics than traditional mercury-based lamps. Modeling of UV reactor performance has been a significant approach to the engineering of UV reactors in drinking water treatment. Yet, no research has been performed on the experimental and modeling of a continuous flow UV-LED reactor. A research study was performed to validate a numerical computational fluid dynamics (CFD) model of a continuous flow UV-LED water disinfection process. Reactor validation consisted of the following: (1) hydraulic analysis using tracer tests, (2) characterization of the average light distribution using chemical actinometry, and (3) microbial dose–response and inactivation using biodosimetry. Results showed good agreement between numerical simulations and experimental testing. Accuracy of fluid velocity profile increased as flow rate increased from 109 mL/min to 190 mL/min, whereas chemical actinometry saw better agreement at the low flow rate. Biodosimetry testing was compared only at the low flow rate and saw good agreement for log inactivation of bacteriophage Qβ and MS-2 at 92% and 80% UV transmittance (UVT). The results from this research can potentially be used for the design of alternative point-of-use drinking water disinfection reactors in developing countries using UV LEDs. DA - 2014/9/6/ PY - 2014/9/6/ DO - 10.1016/j.ces.2014.05.020 VL - 116 SP - 524-535 SN - 1873-4405 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84902352092&partnerID=MN8TOARS KW - Drinking water disinfection KW - UV Light Emitting Diodes KW - Numerical model KW - Chemical actinometry KW - Biodosimetry ER - TY - JOUR TI - Hydrodynamic characterization of Corpus Christi Bay through modeling and observation AU - Islam, Mohammad S. AU - Bonner, James S. AU - Edge, Billy L. AU - Page, Cheryl A. T2 - ENVIRONMENTAL MONITORING AND ASSESSMENT DA - 2014/11// PY - 2014/11// DO - 10.1007/s10661-014-3973-5 VL - 186 IS - 11 SP - 7863-7876 SN - 1573-2959 KW - Hydrodynamic model KW - Corpus Christi Bay KW - Stratification KW - Hypoxia KW - Real-time monitoring KW - High-frequency radar ER - TY - JOUR TI - Fertilization of Radishes, Tomatoes, and Marigolds Using a Large-Volume Atmospheric Glow Discharge AU - Lindsay, Alex AU - Byrns, Brandon AU - King, Wesley AU - Andhvarapou, Asish AU - Fields, Jeb AU - Knappe, Detlef AU - Fonteno, William AU - Shannon, Steven T2 - PLASMA CHEMISTRY AND PLASMA PROCESSING DA - 2014/11// PY - 2014/11// DO - 10.1007/s11090-014-9573-x VL - 34 IS - 6 SP - 1271-1290 SN - 1572-8986 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84907594315&partnerID=MN8TOARS KW - Large-volume glow KW - Atmospheric pressure plasma KW - Fertilization KW - Reactive nitrogen and oxygen species ER - TY - JOUR TI - Enhancing Construction Hazard Recognition with High-Fidelity Augmented Virtuality AU - Albert, Alex AU - Hallowell, Matthew R. AU - Kleiner, Brian AU - Chen, Ao AU - Golparvar-Fard, Mani T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Most construction safety management processes rely on the hazard recognition capability of workers. Hazards that remain unidentified can potentially result in catastrophic injuries and illnesses. As such, thorough hazard recognition is fundamentally essential to protect the health and well-being of the construction workforce. Despite its importance, recent research indicates that a large proportion of hazards remain unrecognized, exposing workers to unmitigated risks. Surprisingly, safety research has not adequately focused on developing specialized strategies to develop construction worker competency in hazard recognition. This paper reports a two-year research effort with the following objectives: (1) develop a high-fidelity augmented virtual environment [System for Augmented Virtuality Environment Safety (SAVES)] that helps develop workers’ hazard recognition skill through risk-free learning and immediate feedback; (2) embed cognitive retrieval mnemonics to improve long-term retention of cues for construction hazards; (3) evaluate the effectiveness of the strategy as an intervention on active construction crew by using the multiple baseline testing approach. The first two objectives were accomplished through a combined effort from a panel of 14 subject matter experts and five academic researchers. This was followed by field experiments to test the hypothesis that the experience with SAVES improves the proportion of hazards identified by participants during subsequent field operations. The findings revealed that crews, on average, were able to only identify 46% of hazards prior to the introduction of the intervention, but were able to recognize 77% of hazards in the postintervention phase. This study represents the first endeavor to measure the effectiveness of augmented virtuality and serious gaming in developing hazard signal detection skills in construction field settings. DA - 2014/7// PY - 2014/7// DO - 10.1061/(asce)co.1943-7862.0000860 VL - 140 IS - 7 SP - SN - 1943-7862 KW - Hazard recognition KW - Safety training KW - Construction safety KW - Hazard identification KW - Augmented virtuality KW - Labor and personnel issues ER - TY - JOUR TI - A protocol for the use of computational fluid dynamics as a supportive tool for wastewater treatment plant modelling AU - Laurent, J. AU - Samstag, R. W. AU - Ducoste, J. M. AU - Griborio, A. AU - Nopens, I. AU - Batstone, D. J. AU - Wicks, J. D. AU - Saunders, S. AU - Potier, O. T2 - WATER SCIENCE AND TECHNOLOGY AB - To date, computational fluid dynamics (CFD) models have been primarily used for evaluation of hydraulic problems at wastewater treatment plants (WWTPs). A potentially more powerful use, however, is to simulate integrated physical, chemical and/or biological processes involved in WWTP unit processes on a spatial scale and to use the gathered knowledge to accelerate improvement in plant models for everyday use, that is, design and optimized operation. Evolving improvements in computer speed and memory and improved software for implementing CFD, as well as for integrated processes, has allowed for broader usage of this tool for understanding, troubleshooting, and optimal design of WWTP unit processes. This paper proposes a protocol for an alternative use of CFD in process modelling, as a way to gain insight into complex systems leading to improved modelling approaches used in combination with the IWA activated sludge models and other kinetic models. DA - 2014/// PY - 2014/// DO - 10.2166/wst.2014.425 VL - 70 IS - 10 SP - 1575-1584 SN - 1996-9732 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84918816988&partnerID=MN8TOARS KW - biokinetic models KW - CFD KW - complex systems KW - fluid motion KW - multi-phase flow KW - transport models ER - TY - JOUR TI - 2,4-D adsorption to biochars: Effect of preparation conditions on equilibrium adsorption capacity and comparison with commercial activated carbon literature data AU - Kearns, J. P. AU - Wellborn, L. S. AU - Summers, R. S. AU - Knappe, D. R. U. T2 - WATER RESEARCH AB - Batch isotherm experiments were conducted with chars to study adsorption of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Chars generated from corncobs, bamboo and wood chips in a laboratory pyrolyzer at 400–700 °C were compared with traditional kiln charcoals collected from villages in S/SE Asia and with activated carbons (ACs). 2,4-D uptake by laboratory chars obtained from bamboo and wood chips after 14 h of pyrolysis at 700 °C, from wood chips after 96 h of pyrolysis at 600 °C, and one of the field-collected chars (basudha) was comparable to ACs. H:C and O:C ratios declined with pyrolysis temperature and duration while surface area increased to >500 m2/g. Increasing pyrolysis intensity by increasing temperature and/or duration of heating was found to positively influence adsorption capacity yield (mg2,4-D/gfeedstock) over the range of conditions studied. Economic analysis showed that high temperature chars can be a cost-effective alternative to ACs for water treatment applications. DA - 2014/10/1/ PY - 2014/10/1/ DO - 10.1016/j.watres.2014.05.023 VL - 62 SP - 20-28 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84902245682&partnerID=MN8TOARS KW - Pesticide KW - Herbicide KW - Water treatment KW - Charcoal KW - Low-cost adsorbent ER - TY - JOUR TI - The role of retrospective weather forecasts in developing daily forecasts of nutrient loadings over the southeast US AU - Oh, J. AU - Sinha, T. AU - Sankarasubramanian, A. T2 - Hydrology and Earth System Sciences AB - Abstract. It is well known in the hydrometeorology literature that developing real-time daily streamflow forecasts in a given season significantly depends on the skill of daily precipitation forecasts over the watershed. Similarly, it is widely known that streamflow is the most important predictor in estimating nutrient loadings and the associated concentration. The intent of this study is to bridge these two findings so that daily nutrient loadings and the associated concentration could be predicted using daily precipitation forecasts and previously observed streamflow as surrogates of antecedent land surface conditions. By selecting 18 relatively undeveloped basins in the southeast US (SEUS), we evaluate the skill in predicting observed total nitrogen (TN) loadings in the Water Quality Network (WQN) by first developing the daily streamflow forecasts using the retrospective weather forecasts based on K-nearest neighbor (K-NN) resampling approach and then forcing the forecasted streamflow with a nutrient load estimation (LOADEST) model to obtain daily TN forecasts. Skill in developing forecasts of streamflow, TN loadings and the associated concentration were computed using rank correlation and RMSE (root mean square error), by comparing the respective forecast values with the WQN observations for the selected 18 Hydro-Climatic Data Network (HCDN) stations. The forecasted daily streamflow and TN loadings and their concentration have statistically significant skill in predicting the respective daily observations in the WQN database at all 18 stations over the SEUS. Only two stations showed statistically insignificant relationships in predicting the observed nitrogen concentration. We also found that the skill in predicting the observed TN loadings increases with the increase in drainage area, which indicates that the large-scale precipitation reforecasts correlate better with precipitation and streamflow over large watersheds. To overcome the limited samplings of TN in the WQN data, we extended the analyses by developing retrospective daily streamflow forecasts over the period 1979–2012 using reforecasts based on the K-NN resampling approach. Based on the coefficient of determination (R2Q-daily) of the daily streamflow forecasts, we computed the potential skill (R2TN-daily) in developing daily nutrient forecasts based on the R2 of the LOADEST model for each station. The analyses showed that the forecasting skills of TN loadings are relatively better in the winter and spring months, while skills are inferior during summer months. Despite these limitations, there is potential in utilizing the daily streamflow forecasts derived from real-time weather forecasts for developing daily nutrient forecasts, which could be employed for various adaptive nutrient management strategies for ensuring better water quality. DA - 2014/8/6/ PY - 2014/8/6/ DO - 10.5194/hess-18-2885-2014 VL - 18 IS - 8 SP - 2885-2898 J2 - Hydrol. Earth Syst. Sci. LA - en OP - SN - 1607-7938 UR - http://dx.doi.org/10.5194/hess-18-2885-2014 DB - Crossref ER - TY - JOUR TI - Synthetic organic water contaminants in developing communities: an overlooked challenge addressed by adsorption with locally generated char 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 - Chemical contamination of drinking water sources is a worldwide problem. However, few locally managed, sustainable, and low-cost on-site treatment technologies are available in rural, remote, and emergency/disaster relief/humanitarian crisis situations. Char filter-adsorbers have been used to treat drinking water for thousands of years and are still widely used today. Our studies show that some chars produced by traditional means from a range of feedstocks develop favorable sorption properties for uptake of 2,4-dichlorophenoxyacetic acid (2,4-D), a prevalent herbicide and water contaminant. However, more energy efficient, environmentally sustainable and scalable production of consistent highly sorptive chars can be accomplished with biomass gasification. Our laboratory studies demonstrate that locally produced char adsorbents derived from surplus agricultural and forestry biomass are effective for adsorbing 2,4-D. A year-long study of field-scale application of chars in Thailand is also presented. Based on these studies we present design recommendations for integrating char adsorbers into low-cost, multi-barrier treatment trains for on-site water provision. DA - 2014/// PY - 2014/// DO - 10.2166/washdev.2014.073 VL - 4 IS - 3 SP - 422-436 SN - 2043-9083 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84907209565&partnerID=MN8TOARS KW - biochar KW - charcoal KW - drinking water KW - herbicide KW - pesticide KW - Thailand ER - TY - JOUR TI - Repair of Reinforced Concrete Bridge Columns Containing Buckled and Fractured Reinforcement by Plastic Hinge Relocation AU - Rutledge, Stephen T. AU - Kowalsky, Mervyn J. AU - Seracino, Rudolf AU - Nau, James M. T2 - Journal of Bridge Engineering AB - This paper describes a new repair technique that involves the use of plastic hinge relocation to restore strength and deformation capacity of RC bridge columns. Summarized is the overall repair concept and experimental results that include the reversed cyclic testing of three large-scale bridge columns that were previously damaged, repaired using the proposed methodology, and then subsequently retested. To date, two different repair alternatives were executed using unidirectional carbon fiber sheets in the hoop and longitudinal directions, the latter anchored into the RC footing with 30-mm-diameter carbon fiber anchors. A method for predicting the force-displacement responses of columns repaired in this manner was also developed and found to give reasonable results. Also included in this paper are design considerations, which are carried out in the steps needed to design a repair system to relocate the plastic hinge in a column containing buckled longitudinal reinforcement. The responses show that the proposed hinge relocation technique is able to restore the lost strength and displacement capacity of damaged RC columns. DA - 2014/8// PY - 2014/8// DO - 10.1061/(asce)be.1943-5592.0000492 VL - 19 IS - 8 SP - J2 - J. Bridge Eng. LA - en OP - SN - 1084-0702 1943-5592 UR - http://dx.doi.org/10.1061/(ASCE)BE.1943-5592.0000492 DB - Crossref KW - Hinge relocation KW - Carbon fiber reinforced polymer repair KW - RC bridge column KW - CFRP anchors KW - Earthquake load histories ER - TY - JOUR TI - Myristoylated Alanine Rich C Kinase Substrate (MARCKS) is essential to beta 2-integrin dependent responses of equine neutrophils AU - Sheats, Mary K. AU - Pescosolido, Kimberly C. AU - Hefner, Ethan M. AU - Sung, Eui Jae AU - Adler, Kenneth B. AU - Jones, Samuel L. T2 - VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY AB - Neutrophil infiltration is a prominent feature in a number of pathologic conditions affecting horses including recurrent airway obstruction, ischemia-reperfusion injury, and laminitis. Cell signaling components involved in neutrophil migration represent targets for novel anti-inflammatory therapies. In order to migrate into tissue, neutrophils must respond to chemoattractant signals in their external environment through activation of adhesion receptors (i.e. integrins) and reorganization of the actin cytoskeleton. Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS), a highly conserved actin-binding protein, has a well demonstrated role in cytoskeletal dependent cellular functions (i.e. adhesion, spreading, and migration), but the details of MARCKS involvement in these processes remain vague. We hypothesized that MARCKS serves as a link between the actin cytoskeleton and integrin function in neutrophils. Using a MARCKS-specific inhibitor peptide known as MANS on equine neutrophils in vitro, we demonstrate that inhibition of MARCKS function significantly attenuates β2-integrin-dependent neutrophil functions including migration, adhesion, and immune complex-mediated respiratory burst. The MANS peptide did not, however, inhibit the β2-integrin-independent PMA mediated respiratory burst. These results attest to the essential role of MARCKS function in regulating neutrophil responses, and strongly implicate MARCKS as a potential regulator of β2-integrins in neutrophils. DA - 2014/8/15/ PY - 2014/8/15/ DO - 10.1016/j.vetimm.2014.04.009 VL - 160 IS - 3-4 SP - 167-176 SN - 1873-2534 KW - Neutrophil KW - Migration KW - Adhesion KW - Respiratory burst KW - Beta2-integrin KW - Inflammation ER - TY - JOUR TI - Low-temperature properties of plant-produced RAP mixtures in the Northeast AU - Mensching, D. J. AU - Daniel, J. S. AU - Bennert, T. AU - Medeiros, M. S. AU - Elwardany, M. D. AU - Mogawer, W. AU - Hajj, E. Y. AU - Alavi, M. Z. T2 - Road Materials and Pavement Design DA - 2014/// PY - 2014/// VL - 15 SP - 1-27 ER - TY - JOUR TI - Implications of warm-mix asphalt on long-term oxidative ageing and fatigue performance of asphalt binders and mixtures AU - Safaei, Farinaz AU - Lee, Jong-sub AU - Nascimento, Luis Alberto Hermann do AU - Hintz, Cassie AU - Kim, Y. Richard T2 - Road Materials and Pavement Design AB - AbstractThe use of warm mix asphalt (WMA) has been increasing in recent years due to its ability to reduce the production temperatures of asphalt concrete. The long-term implications of reduced production temperatures and, hence, reduced short-term ageing on long-term performance remain largely unknown. This study evaluates the effect of age hardening in WMA binders and mixtures compared with hot mix asphalt (HMA) binders and mixtures with respect to fatigue damage. Two WMA technologies are considered: foaming by water injection and Evotherm modification. For this study, the asphalt mixtures were subjected to laboratory conditioning in a forced air convection oven to simulate long-term field ageing according to AASHTO R30. The asphalt mixtures and extracted binders were subjected to linear viscoelastic and fatigue characterisation following ageing. Because oxidative ageing occurs within the asphalt binder phase of asphalt concrete, this paper focuses on the relative performance of WMA and HMA binders at various ageing levels and compares this binder performance to the respective mixture performance. Cyclic direct tension tests were used to measure the fatigue resistance of the asphalt mixtures, and the linear amplitude sweep (LAS) test was used to measure the fatigue resistance of the binders. Simplified viscoelastic continuum damage (S-VECD) analysis was performed to interpret the fatigue test results and predict the fatigue performance of the binders and mixtures using a pavement structural model. The results demonstrate that after substantial long-term ageing, differences between the fatigue performance of WMA and HMA become insignificant. The results also demonstrate good agreement between the binder and mixture results, indicating that the LAS test coupled with S-VECD analysis is able to capture the binder's contribution to mixture fatigue.Keywords: warm-mixoxidationfatigueviscoelastic continuum damageasphalt binder DA - 2014/6/26/ PY - 2014/6/26/ DO - 10.1080/14680629.2014.927050 VL - 15 IS - sup1 SP - 45-61 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2014.927050 DB - Crossref KW - warm-mix KW - oxidation KW - fatigue KW - viscoelastic continuum damage KW - asphalt binder ER - TY - JOUR TI - Implementation and verification of a mechanistic permanent deformation model (shift model) to predict rut depths of asphalt pavement AU - Choi, Yeong-Tae AU - Kim, Y. Richard T2 - ROAD MATERIALS AND PAVEMENT DESIGN AB - The shift model is implemented in the layered viscoelastic asphalt pavement analysis for critical distresses (LVECD) program to predict the rut depth of asphalt pavements. The rut depth measurements taken at the National Center for Asphalt Technology (NCAT) test track and the Federal Highway Administration Accelerated Facility (FHWA ALF) test sections are evaluated using the model. The model can successfully evaluate rut depth, which proves the capability of the model implemented in the LVECD program. The slight over-prediction of the NCAT sections can be explained by ageing in the field that increases the pavement's resistance to rutting. The simulation results support the hypothesis that triaxial stress sweep tests with confinement can represent the permanent deformation behaviour of asphalt concrete in the field. In this regard, excessive shear flow may be the reason for the under-prediction of the FHWA ALF mixtures. For better predictions, a correction factor (i.e. a transfer function) is suggested, which is quantified via the ratio of shear stress to shear resistance. After applying individual transfer functions, the permanent deformation model in the LVECD can evaluate the growth of the rut depth. Therefore, even though the shift model is a uniaxial model, the model can predict the rut depth of asphalt concrete by employing the transfer function. DA - 2014/// PY - 2014/// DO - 10.1080/14680629.2014.927085 VL - 15 SP - 195-218 SN - 2164-7402 KW - permanent deformation model KW - rutting KW - shift model KW - shear flow KW - rut depth prediction ER - TY - JOUR TI - From Social Network to Data Envelopment Analysis: Identifying Benchmarks at the Site Management Level AU - Abbasian-Hosseini, S. Alireza AU - Hsiang, Simon M. AU - Leming, Michael L. AU - Liu, Min T2 - Journal of Construction Engineering and Management AB - AbstractIt is widely accepted in the construction industry that contract documents, specifying the responsibility and risk of each participant, are the basis for project managers’ and superintendents’ decision making (DM). However, in practice strict adherence to the formal procedures and chains of command would not always be possible without an unacceptable expenditure of time and money. Although much attention is given to the decisions at the project manager and superintendent level, the underlying rules and mechanisms for the moment-to-moment DM at the site management level has not been documented. In this paper, a social network (SN)–based data envelopment analysis (DEA) benchmarking procedure (SDBP), which combines DEA (assessing the relative efficiency of DM units) and SN (concentrating on the relationships amongst DM units) to identify the benchmarks for the inefficient specialty trades (STs). This paper also uses a case study to illustrate how to implement the SDBP. This research contributes to th... DA - 2014/8// PY - 2014/8// DO - 10.1061/(asce)co.1943-7862.0000875 VL - 140 IS - 8 SP - 04014028 J2 - J. Constr. Eng. Manage. LA - en OP - SN - 0733-9364 1943-7862 UR - http://dx.doi.org/10.1061/(ASCE)CO.1943-7862.0000875 DB - Crossref KW - Benchmark KW - Social factors KW - Data analysis KW - Internet KW - Construction industry KW - Contract management KW - Benchmarking KW - Social network KW - Data envelopment analysis KW - Social learning KW - Construction trades KW - Labor and personnel issues ER - TY - JOUR TI - Experimental field testing of a real-time construction hazard identification and transmission technique AU - Albert, Alex AU - Hallowell, Matthew R. AU - Kleiner, Brian M. T2 - CONSTRUCTION MANAGEMENT AND ECONOMICS AB - Hazard identification and communication are integral to most construction methods, and every construction safety management activity. Unfortunately, in practice, significant hazards are often not recognized and communicated leading to sub-optimal hazard awareness at the crew level. To bridge this gap in performance, we conducted a two-year intensive research project focused on developing a strategy that increases the proportion of hazards identified, communicated, and managed. Specifically, we designed a hazard identification and transmission (HIT) board that is used in conjunction with energy-based retrieval mnemonics and facilitates identifying and communicating hazards during both the planning and the execution phases. The strength of this strategy lies in the fact that workers are able to detect and communicate hazards in real time using energy-source mnemonic cues, which significantly reduces cognitive demand. Following development, we conducted immersive field studies to evaluate the impact of the devised strategy on two projects in the United States. Data from six crews were gathered using the rigorous multiple baseline testing experimental approach and analysis was conducted using interrupted time-series regression models. The results indicate that the crews were able to recognize and communicate only an average of 54% of hazards in the baseline phase, but were able to recognize and communicate 77% during the planning phase after using the intervention. An additional 6% of hazards were identified and communicated in the execution phase. This represents the first known formal effort to evaluate a real-time hazard identification and communication strategy for the construction industry. DA - 2014/// PY - 2014/// DO - 10.1080/01446193.2014.929721 VL - 32 IS - 10 SP - 1000-1016 SN - 1466-433X KW - Communication KW - hazard identification KW - hazard recognition KW - health and safety KW - safety ER - TY - JOUR TI - Emerging strategies for construction safety and health hazard recognition AU - Albert, A. AU - Hallowell, M.R. AU - Kleiner, B T2 - Journal of Safety, Health, and Environmental Research DA - 2014/// PY - 2014/// VL - 10 IS - 2 SP - 152-161 ER - TY - JOUR TI - Calibration and field validation of four double-crossover diamond interchanges in VISSIM microsimulation AU - Schroeder, B. J. AU - Salamati, K. AU - Hummer, J. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2404 SP - 49-58 ER - TY - JOUR TI - Volume-Change Behavior of a Compacted Low-Plasticity Clay From Double-Odometer Tests AU - Kim, Wan Soo AU - Borden, Roy H. T2 - GEOTECHNICAL TESTING JOURNAL AB - The compressibility of compacted soils is not only a function of soil type and density but also stress state, which is influenced by the existing matric suction and can be described using the fundamentals of unsaturated soil mechanics. This paper presents data from double-odometer tests on low-plasticity clay that demonstrates the effects of dry density and water content on volume-change behavior. Using the data set developed, the drained constrained modulus is determined using the stress–strain relations obtained from conventional odometer tests on soaked specimens, as well as specimens at their molding moisture content. The change of modulus with respect to degree of saturation is discussed and placed in context with the model used in the Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures [ARA, ERES Consultants Division, 2004, “Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures,” Final Report NCHRP Project 1-37A, Transportation Research Board of the National Academies, Washington, D.C.]. A procedure for predicting the undrained modulus from the constitutive relation for drained loading and the predicted excess pore pressure caused by loading based on a modification of Hilf’s equation [Hilf, J. W., 1948, “Estimating Construction Pore Pressures in Rolled Earth Dams,” Proceedings of the 2nd International Conference on Soil Mechanics and Foundation Engineering, Vol. 3, International Society for Soil Mechanics and Foundation Engineering (ISSMGE), London, pp. 234–240] is also presented and discussed. DA - 2014/5// PY - 2014/5// DO - 10.1520/gtj20120047 VL - 37 IS - 3 SP - SN - 1945-7545 KW - constrained modulus KW - drained and undrained loading conditions KW - one-dimensional odometer test KW - compaction condition KW - matric suction KW - degree of saturation ER - TY - JOUR TI - Orthogonal zirconium diol/C18 liquid chromatography-tandem mass spectrometry analysis of poly and perfluoroalkyl substances in landfill leachate AU - Allred, B. McKay AU - Lang, Johnsie R. AU - Barlaz, Morton A. AU - Field, Jennifer A. T2 - JOURNAL OF CHROMATOGRAPHY A AB - Leachates coming from landfills contain a myriad of compounds of potential environmental and human health concern, including per- and polyfluorinated alkyl substances (PFASs). Micro liquid-liquid extraction was combined with a 900 μl large volume injection (LVI) for the analysis of 70 PFASs in landfill leachate by orthogonal LC-MS/MS. The LVI approach introduced 7 times more extract than conventional injection approaches. Two zirconium-modified diol guard columns effectively retained PFASs from the organic leachate extract and an analytical C18 column was used for separation. Method accuracy and precision for PFASs with analytical grade reference materials ranged from 81–120% and 5.5–33%, respectively. Estimated method detection limits in the low to sub-ng/L. Seven landfill leachates were analyzed by the optimized analytical method for the purposes of method demonstration. Leachates were characterized by a wide variety of PFASs, reporting on 36 previously-unanalyzed PFASs in leachate. Perfluoroalkyl carboxylates were the most abundant class detected while phosphorous-containing PFASs, present in all leachates, were at low concentrations. The 3-perfluoropentyl propanoate (5:3 FTCA) was the most concentrated analyte in most samples and constitutes a previously unreported but significant component of landfill leachate. DA - 2014/9/12/ PY - 2014/9/12/ DO - 10.1016/j.chroma.2014.07.056 VL - 1359 SP - 202-211 SN - 1873-3778 KW - Landfill leachates KW - LVI KW - LC-MS/MS KW - PFAS ER - TY - JOUR TI - Modeling seasonal heteroscedasticity in vehicular traffic condition series using a seasonal adjustment approach (vol 140, 04014012, 2014) AU - Shi, G. G. AU - Guo, J. H. AU - Huang, W. AU - Williams, B. M. T2 - Journal of Transportation Engineering DA - 2014/// PY - 2014/// VL - 140 IS - 9 ER - TY - JOUR TI - Hydrologic Impact Assessment of Land Cover Change and Stormwater Management Using the Hydrologic Footprint Residence AU - Giacomoni, M.H. AU - Gomez, R. AU - Berglund, E.Z. T2 - JAWRA Journal of the American Water Resources Association AB - Abstract Urbanization impacts the stormwater regime through increased runoff volumes and velocities. Detention ponds and low impact development ( LID ) strategies may be implemented to control stormwater runoff. Typically, mitigation strategies are designed to maintain postdevelopment peak flows at predevelopment levels for a set of design storms. Peak flow does not capture the extent of changes to the hydrologic flow regime, and the hydrologic footprint residence ( HFR ) was developed to calculate the area and duration of inundated land during a storm. This study couples a cellular automata land cover change model with a hydrologic and hydraulic framework to generate spatial projections of future development on the fringe of a rapidly urbanizing metropolitan area. The hydrologic flow regime is characterized for existing and projected land cover patterns under detention pond and LID ‐based control, using the HFR and peak flow values. Results demonstrate that for less intense and frequent rainfall events, LID solutions are better with respect to HFR ; for larger storms, detention pond strategies perform better with respect to HFR and peak flow. DA - 2014/4/28/ PY - 2014/4/28/ DO - 10.1111/jawr.12187 VL - 50 IS - 5 SP - 1242-1256 J2 - J Am Water Resour Assoc LA - en OP - SN - 1093-474X UR - http://dx.doi.org/10.1111/jawr.12187 DB - Crossref KW - hydrologic footprint residence KW - land cover change KW - urbanization KW - stormwater management KW - cellular automata KW - low impact development KW - sustainability KW - smart growth KW - detention pond ER - TY - JOUR TI - Enhanced Nitrogen Removal by Rice Husk Amended Dynamic Membrane Bioreactors AU - Fu, DaFang AU - Kai, Hong AU - Singh, Rajendra Prasad AU - Ducoste, Joel J. T2 - Journal of Environmental Engineering AB - Effective and low-cost dynamic membrane bioreactors (DMBR) can be a strong option for wastewater treatment in developing countries. The goal of this study was to investigate the effect of rice husk addition on the DMBR’s nitrogen removal performance. Tests were performed at both lab-scale and pilot-scale facilities. Results showed that rice husk served as a suitable biofilm carrier as well as an effective denitrification carbon source. In lab-scale experiments, the removal efficiency of rice husk amended DMBR for chemical oxygen demand (COD), NH3-N, and total nitrogen (TN) was 96.7, 96.3, and 80.4%, respectively. Results from the pilot-scale DMBR system showed that removal efficiency for COD and NH3-N was 90.3 and 95.2%, respectively, whereas TN removal was comparatively lower (50.5%). Fluorescence in situ hybridization (FISH) analysis showed that the bacterial population was higher in the rice husk added DMBR than the controlled DMBR, and ammonia-oxidizing bacteria were the main components of total heterotrophic bacteria. Overall, the rice husk dosing has improved the simultaneous nitrification-denitrification (SND) rate by 9.7% in DMBR and can be an economical and effective carbon source for the total nitrogen removal process. DA - 2014/11// PY - 2014/11// DO - 10.1061/(asce)ee.1943-7870.0000840 VL - 140 IS - 11 SP - 04014035 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000840 DB - Crossref KW - Dynamic membrane bioreactor KW - Nitrogen removal KW - Biological carbon sources KW - Wastewater treatment ER - TY - JOUR TI - Dynamic Threshold Cash Flow-Based Structural Model for Contractor Financial Prequalification AU - Huang, Wen-Haw AU - Tserng, H. Ping AU - Jaselskis, Edward J. AU - Lee, Shu-Yi T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - It is important for project owners to select only those construction contractors who are uniquely qualified to perform the work because this leads to the greatest chance for achieving project success. Owners typically screen contractors by using the following key criteria: financial stability, technical ability, management capability, health and safety, and reputation. This study focuses primarily on the construction contractor’s financial stability during the prequalification phase and employs a dynamic threshold cash flow based structural model (DCFM) to assess the credit quality score for each construction contractor. This model differs from the existing credit model because it only requires accounting statement information; thus, it is applicable to both publicly listed and private construction contractors. Moreover, only a small portion of companies are rated in the construction industry; this model is especially useful for owners to assess the credit quality of unrated construction companies. The Standard & Poor’s issuer credit rating is used as the benchmark to evaluate the model’s discrimination ability to differentiate financially qualified contractors from unqualified contractors. Additionally, the validation indicator area under curve (AUC) is utilized to demonstrate whether the DCFM can identify different credit grade firms according to the model’s credit quality scores. The AUC results of the first three years of this model are 0.861, 0.833, and 0.819, indicating that this model achieves excellent discriminatory ability and is useful for assessing the credit risk of construction contractors. DA - 2014/10// PY - 2014/10// DO - 10.1061/(asce)co.1943-7862.0000902 VL - 140 IS - 10 SP - SN - 1943-7862 KW - Contractor financial prequalification KW - Credit risk KW - Dynamic threshold KW - Cash flow structural model KW - Receiver operating characteristic curve KW - Quantitative methods ER - TY - JOUR TI - Comparison of Fine Particulate Matter and Carbon Monoxide Exposure Concentrations for Selected Transportation Modes AU - Jiao, Wan AU - Frey, H. Christopher T2 - TRANSPORTATION RESEARCH RECORD AB - Daily commutes may contribute disproportionately to overall daily exposure to urban air pollutants such as particulate matter less than 2.5 &Mu;m (PM 2.5 ) and carbon monoxide (CO). PM 2.5 and CO concentrations were measured and compared across pedestrian, bus, and car modes during lunchtime and the afternoon peak hour within a 3–week time period on preselected round-trip routes. Variability in the concentration ratios of PM 2.5 and CO for the selected transportation modes was quantified, and factors affecting variability in concentrations were identified. Exposure concentrations of transportation modes were sensitive to mode and were affected by factors such as vehicle ventilation and proximity to on-road emission sources. In general, pedestrian and bus modes had higher PM 2.5 concentrations than did the car mode. However, the car mode had the highest average CO concentrations among the selected modes. Near-road pedestrian PM 2.5 concentrations generally covaried with fixed site monitor (FSM) measurements, but there was little correlation between pedestrian CO concentrations and FSM data. Field studies such as this one are needed to develop input data for simulation models of population-based exposure to predict more accurately exposure concentrations for transportation modes. DA - 2014/// PY - 2014/// DO - 10.3141/2428-07 IS - 2428 SP - 54-62 SN - 2169-4052 ER - TY - JOUR TI - Application of AIMSUN microsimulation model to estimate emissions on signalized arterial corridors AU - Anya, A. AU - Rouphail, N. AU - Frey, H. AU - Schroeder, B. T2 - Transportation Research Record AB - Tailpipe emissions from on-road vehicles have negative impacts on the air quality of a region and are influenced by several factors including driver behavior, road characteristics, and traffic conditions. Typically vehicles on arterial roads frequently stop and then accelerate, a behavior that produces more tailpipe emissions than does maintaining a steady speed. Microscopic simulation models generate synthetic vehicle activity that can be used to estimate emissions on a facility. For emissions to be estimated accurately from an arterial facility, the simulated activity must closely represent the activity observed in the field. This study investigated whether a selected set of simulation parameters that used speed trajectories observed in the field at high temporal resolution could improve the emissions estimated from a simulated signalized arterial corridor. The simulated trajectories and those observed in the field were characterized by vehicle-specific power (VSP). Emissions were estimated with VSP modal emission rates and the time spent by vehicles in each VSP mode. The emissions were compared for routes along an urban arterial facility and for shorter segments within routes. At both spatial scales, the emissions from parameter-adjusted simulation vehicles that had the same average number of stops and travel time distribution as vehicles observed in the field were closer to real-world emissions than were the simulation vehicles under default model parameters. Adjusting the parameters also allowed the model to capture emissions hot spots along the routes more accurately. Currently, microscopic simulation models are calibrated with traffic performance measures that are improving. The findings from this paper present the potential for using these improving emissions estimates from simulated vehicle activity for the additional calibration of microsimulation models. DA - 2014/// PY - 2014/// DO - 10.3141/2428-09 VL - 2428 IS - 2428 SP - 75-86 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84907481905&partnerID=MN8TOARS ER - TY - JOUR TI - Study of MEPDG Sensitivity Using Nonparametric Regression Procedures AU - Tarefder, Rafiqul A. AU - Sumee, Nasrin AU - Storlie, Curtis T2 - JOURNAL OF COMPUTING IN CIVIL ENGINEERING AB - Because the new Mechanistic-Empirical Pavement Design Guide (MEPDG) includes numerous inputs, a sensitivity analysis using the Monte Carlo approach is not practical because it requires thousands of MEPDG runs. Instead, nonparametric regression procedures can be very useful to perform MEPDG sensitivity analysis. In this study, nonparametric regression procedures such as multivariate adaptive regression splines and gradient boosting machine are employed to identify inputs that contribute significantly to the outputs. Thirty inputs are used to randomly generate 750 input combinations by using Latin hypercube sampling. Using four-layer pavement geometry [two asphalt concrete (AC), base, and subgrade layers], simulations are run in MEPDG software to produce a time series of predicted distresses such as roughness, rutting, and cracking. Sensitivity analysis resulted in three groups of inputs to which the output is (1) highly sensitive, (2) moderately sensitive, and (3) minimally sensitive. Results show that roughness is highly sensitive to traffic input variables such as annual average daily truck traffic (AADTT), percentage of trucks in the design lane, and thickness of bottom AC layer. AC rutting is highly affected by AADTT, percentage of trucks in design direction, and tire pressure. Three major factors for total rutting, longitudinal cracking, and alligator cracking are AADTT, percentage of trucks in design direction, and thickness of bottom AC layer. In addition to these, alligator cracking is highly sensitive to percentage of air voids in the bottom AC layer. Transverse cracking is highly sensitive to the percentage of trucks in the design lane, percentage of Class 11 vehicles, plastic limit, thickness of base layer, effective binder content of top AC layer, and climate. Among all of the inputs, the thickness of the AC layer is highly interactive with other input variables. DA - 2014/1/1/ PY - 2014/1/1/ DO - 10.1061/(asce)cp.1943-5487.0000239 VL - 28 IS - 1 SP - 134-144 SN - 1943-5487 KW - Sensitivity analysis KW - Statistics KW - Sampling KW - Pavements KW - Mechanistic-Empirical Pavement Design Guide KW - Sensitivity analysis KW - Advanced statistical analysis KW - Latin hypercube sampling KW - Nonparametric regression KW - Confidence intervals ER - TY - JOUR TI - Improved regional water management utilizing climate forecasts: An interbasin transfer model with a risk management framework AU - Li, Weihua AU - Sankarasubramanian, A. AU - Ranjithan, R. S. AU - Brill, E. D. T2 - Water Resources Research AB - Abstract Regional water supply systems undergo surplus and deficit conditions due to differences in inflow characteristics as well as due to their seasonal demand patterns. This study proposes a framework for regional water management by proposing an interbasin transfer (IBT) model that uses climate‐information‐based inflow forecast for minimizing the deviations from the end‐of‐season target storage across the participating pools. Using the ensemble streamflow forecast, the IBT water allocation model was applied for two reservoir systems in the North Carolina Triangle Area. Results show that interbasin transfers initiated by the ensemble streamflow forecast could potentially improve the overall water supply reliability as the demand continues to grow in the Triangle Area. To further understand the utility of climate forecasts in facilitating IBT under different spatial correlation structures between inflows and between the initial storages of the two systems, a synthetic experiment was designed to evaluate the framework under inflow forecast having different skills. Findings from the synthetic study can be summarized as follows: (a) inflow forecasts combined with the proposed IBT optimization model provide improved allocation in comparison to the allocations obtained under the no‐transfer scenario as well as under transfers obtained with climatology; (b) spatial correlations between inflows and between initial storages among participating reservoirs could also influence the potential benefits that could be achieved through IBT; (c) IBT is particularly beneficial for systems that experience low correlations between inflows or between initial storages or on both attributes of the regional water supply system. Thus, if both infrastructure and permitting structures exist for promoting interbasin transfers, season‐ahead inflow forecasts could provide added benefits in forecasting surplus/deficit conditions among the participating pools in the regional water supply system. DA - 2014/8// PY - 2014/8// DO - 10.1002/2013wr015248 VL - 50 IS - 8 SP - 6810-6827 J2 - Water Resour. Res. LA - en OP - SN - 0043-1397 UR - http://dx.doi.org/10.1002/2013WR015248 DB - Crossref KW - regional water management KW - inflow forecasts KW - interbasin transfer ER - TY - JOUR TI - Finite element study of behavior and interface force conditions of seven-wire strand under axial and lateral loading AU - Yu, Yujie AU - Chen, Zhihua AU - Liu, Hongbo AU - Wang, Xiaodun T2 - CONSTRUCTION AND BUILDING MATERIALS AB - Although numerous FE models have been proposed to analyze the mechanical behavior of simple strands, they seldom examine the contact condition and lateral loading behavior that may influence local stress distribution and lifetime performance. In this study, serial 3D FE models of a seven-wire strand were developed to discover the interface mechanism under longitudinal and lateral loading. A partially restrained model was proposed and carefully studied. Friction minimally influenced longitudinal stiffness and had a limited effect on lateral behavior. FEM analysis predicted uneven stress distribution under lateral loading simulation. Both strand bending phase and wire bending phase were observed near the termination. Microslip and contact line migration mainly occurred between helical wires. DA - 2014/9/15/ PY - 2014/9/15/ DO - 10.1016/j.conbuildmat.2014.05.009 VL - 66 SP - 10-18 SN - 1879-0526 KW - Seven-wire strand cable KW - Finite element method KW - Longitudinal stiffness KW - Lateral loading KW - Interface force conditions KW - Friction ER - TY - JOUR TI - Electrical impedance tomography-based sensing skin for quantitative imaging of damage in concrete AU - Hallaji, Milad AU - Seppanen, Aku AU - Pour-Ghaz, Mohammad T2 - SMART MATERIALS AND STRUCTURES AB - This paper outlines the development of a large-area sensing skin for damage detection in concrete structures. The developed sensing skin consists of a thin layer of electrically conductive copper paint that is applied to the surface of the concrete. Cracking of the concrete substrate results in the rupture of the sensing skin, decreasing its electrical conductivity locally. The decrease in conductivity is detected with electrical impedance tomography (EIT) imaging. In previous works, electrically based sensing skins have provided only qualitative information on the damage on the substrate surface. In this paper, we study whether quantitative imaging of the damage is possible. We utilize application-specific models and computational methods in the image reconstruction, including a total variation (TV) prior model for the damage and an approximate correction of the modeling errors caused by the inhomogeneity of the painted sensing skin. The developed damage detection method is tested experimentally by applying the sensing skin to polymeric substrates and a reinforced concrete beam under four-point bending. In all test cases, the EIT-based sensing skin provides quantitative information on cracks and/or other damages on the substrate surface: featuring a very low conductivity in the damage locations, and a reliable indication of the lengths and shapes of the cracks. The results strongly support the applicability of the painted EIT-based sensing skin for damage detection in reinforced concrete elements and other substrates. DA - 2014/8// PY - 2014/8// DO - 10.1088/0964-1726/23/8/085001 VL - 23 IS - 8 SP - SN - 1361-665X KW - absolute imaging KW - concrete KW - electrical impedance tomography (EIT) KW - non-destructive testing KW - reinforced concrete KW - sensing skin KW - total variation (TV) prior ER - TY - JOUR TI - Assessing methods to estimate emissions of non-methane organic compounds from landfills AU - Saquing, Jovita M. AU - Chanton, Jeffrey P. AU - Yazdani, Ramin AU - Barlaz, Morton A. AU - Scheutz, Charlotte AU - Blake, Don R. AU - Imhoff, Paul T. T2 - WASTE MANAGEMENT AB - The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i.e., individual NMOC emissions): speciated NMOC emissions = measured methane (CH4) emission multiplied by the ratio of individual NMOCs concentration relative to CH4 concentration (CNMOCs/CCH4) in the landfill header gas. The objectives of this study were to (1) evaluate the efficacy of the ratio method in estimating speciated NMOC flux from landfills; (2) determine for what types of landfills the ratio method may be in error and why, using recent field data to quantify the spatial variation of (CNMOCs/CCH4) in landfills; and (3) formulate alternative models for estimating NMOC emissions from landfills for cases in which the ratio method results in biased estimates. This study focuses on emissions through landfill covers measured with flux chambers and evaluates the utility of the ratio method for estimating NMOC emission through this pathway. Evaluation of the ratio method was performed using CH4 and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (<40 cm), predicting composite NMOC flux (as hexane-C) to within a factor of 10× for 13 out of 15 measurements. However, for thick covers (⩾40 cm) the ratio method overestimated NMOC emissions by ⩾10× for 8 out of 10 measurements. Alternative models were explored incorporating other chemical properties into the ratio method. A molecular weight squared (MW)2-modified ratio equation was shown to best address the tendency of the current ratio method to overestimate NMOC fluxes for thick covers. While these analyses were only performed using NMOC fluxes through landfill covers measured with flux chambers, results indicate the current USEPA approach for estimating NMOC emissions may overestimate speciated NMOC emission ⩾10× for many compounds. DA - 2014/11// PY - 2014/11// DO - 10.1016/j.wasman.2014.07.007 VL - 34 IS - 11 SP - 2260-2270 SN - 0956-053X KW - NMOC emission KW - NMOC flux estimation KW - Field measurement KW - Landfill gas emission ER - TY - JOUR TI - Adaptive Kalman filter approach for stochastic short-term traffic flow rate prediction and uncertainty quantification AU - Guo, Jianhua AU - Huang, Wei AU - Williams, Billy M. T2 - TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES AB - Short term traffic flow forecasting has received sustained attention for its ability to provide the anticipatory traffic condition required for proactive traffic control and management. Recently, a stochastic seasonal autoregressive integrated moving average plus generalized autoregressive conditional heteroscedasticity (SARIMA + GARCH) process has gained increasing notice for its ability to jointly generate traffic flow level prediction and associated prediction interval. Considering the need for real time processing, Kalman filters have been utilized to implement this SARIMA + GARCH structure. Since conventional Kalman filters assume constant process variances, adaptive Kalman filters that can update the process variances are investigated in this paper. Empirical comparisons using real world traffic flow data aggregated at 15-min interval showed that the adaptive Kalman filter approach can generate workable level forecasts and prediction intervals; in particular, the adaptive Kalman filter approach demonstrates improved adaptability when traffic is highly volatile. Sensitivity analyses show that the performance of the adaptive Kalman filter stabilizes with the increase of its memory size. Remarks are provided on improving the performance of short term traffic flow forecasting. DA - 2014/6// PY - 2014/6// DO - 10.1016/j.trc.2014.02.006 VL - 43 SP - 50-64 SN - 0968-090X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84902553625&partnerID=MN8TOARS KW - Congestion KW - Intelligent transportation system KW - Short term traffic flow forecasting KW - SARIMA KW - GARCH KW - Adaptive Kalman filter ER - TY - JOUR TI - A new sensing skin for qualitative damage detection in concrete elements: Rapid difference imaging with electrical resistance tomography AU - Hallaji, Milad AU - Pour-Ghaz, Mohammad T2 - NDT & E INTERNATIONAL AB - In this paper we investigate whether a thin layer of electrically conductive materials that is painted to the surface of concrete elements can be used as sensing skin to detect and locate cracking and damage in the concrete substrate. Cracking of the concrete results in the rupture of the sensing skin, thus locally increasing its electrical resistivity. We monitor the local change in the electrical resistivity of the sensing skin using electrical resistance tomography. In this work, we utilize difference imaging scheme. Experiments on polymeric substrates as well as on concrete substrates are performed. The results indicate that the developed sensing skin can be successfully used to detect and locate cracking and damage on concrete and potentially other nonconductive substrates. DA - 2014/12// PY - 2014/12// DO - 10.1016/j.ndteint.2014.07.006 VL - 68 SP - 13-21 SN - 1879-1174 KW - Concrete KW - Damage detection KW - Electrical resistance tomography KW - Sensing skin sensor KW - Structural health monitoring ER - TY - JOUR TI - Understanding Poor Seismic Performance of Concrete Walls and Design Implications AU - Sritharan, Sri AU - Beyer, Katrin AU - Henry, Richard S. AU - Chai, Y. H. AU - Kowalsky, Mervyn AU - Bull, Desmond T2 - EARTHQUAKE SPECTRA AB - The 2010–2011 Canterbury earthquakes in New Zealand revealed (1) improved structural response resulting from historical design advancements, (2) poor structural performance due to previously identified shortcomings that had been insufficiently addressed in design practice, and (3) new deficiencies that were not previously recognized because of premature failure resulting from other design flaws. This paper summarizes damage to concrete walls observed in the February 2011 Christchurch earthquake, proposes links between the observed response and specific design concerns, and offers suggestions for improving seismic design of walls in the following areas: amount of longitudinal reinforcement in wall end regions, suitable wall thickness to minimize the potential for out-of-plane buckling, and minimum vertical reinforcement requirements. DA - 2014/2// PY - 2014/2// DO - 10.1193/021713eqs036m VL - 30 IS - 1 SP - 307-334 SN - 1944-8201 ER - TY - JOUR TI - Perchlorate natural attenuation in a riparian zone AU - Borden, Robert C. AU - Knox, Sheri L. AU - Lieberman, M. Tony AU - Ogles, Dora T2 - JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING AB - Multiple lines of evidence were used to document the natural attenuation of perchlorate in a shallow alluvial aquifer. In the upgradient, aerobic portion of the aquifer, perchlorate did not biodegrade. However, natural flushing by groundwater flow is reducing perchlorate concentrations in the aquifer over time. Perchlorate concentrations in the source area are expected to meet cleanup criteria in 11 to 27 years without active remedial measures. At the distal end of the plume, perchlorate is rapidly degraded as it migrates upward through organic rich littoral zone sediments. Apparent first-order degradation rates in groundwater were about 0.20 d(-1) and are consistent with laboratory macrocosm rates (0.12 d(-1)). qPCR results show a distinct region of the littoral zone where perchlorate degraders are elevated. The Eh within this zone varies from +0.1 to +0.3 V indicating perchlorate degraders can thrive in moderately oxidizing conditions. The study has shown that (i) there was no apparent perchlorate biodegradation in aerobic aquifer; (ii) perchlorate declines over time in aerobic aquifer due to flushing; (iii) there was a rapid perchlorate attenuation in organic rich littoral zone; and, (iv) qPCR results show large increases in perchlorate degraders in the littoral zone. DA - 2014/// PY - 2014/// DO - 10.1080/10934529.2014.897145 VL - 49 IS - 10 SP - 1100-1109 SN - 1532-4117 KW - Perchlorate KW - littoral zone KW - natural attenuation KW - qPCR ER - TY - JOUR TI - Mean profile depth analysis of field and laboratory traffic-loaded chip seal surface treatments AU - Adams, Javon M. AU - Kim, Y. Richard T2 - INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING AB - This paper presents a laboratory and field study to evaluate the mean profile depth (MPD) parameter that represents the surface texture of chip seal pavements. A three-dimensional laser profiler is used to determine the MPD values from both field pavement sections and field samples that have been tested in the laboratory using the third-scale model mobile loading simulator (MMLS3). Data obtained from five different field-constructed chip seal sections are used to evaluate the effects of different factors on the MPD of chip seal pavements. These factors include aggregate type, emulsion application rate, field versus MMLS3 traffic loading and traffic volume. The results presented in this paper suggest that: (1) chip seal pavements constructed using lightweight aggregate have larger initial MPD values and faster reduction in MPD as a function of the number of wheel passes than those constructed using granite 78M aggregate; (2) MPD values obtained from a drier section (with drier indicating a lower emulsion-to-aggregate ratio than that of the sections it is being compared against) initially drop quickly and significantly, resulting in a much smaller ultimate MPD value; (3) in general, the MPD values obtained under MMLS3 loading are similar to those obtained from field traffic loading, thus allowing the translation of the laboratory MMLS3 data to the field response data; (4) a short rest period in a high-traffic volume road retards the recovery of the binder and, therefore, leads to more permanent changes in the MPD and (5) the initial measured MPD value can help predict aggregate loss performance. DA - 2014/8/9/ PY - 2014/8/9/ DO - 10.1080/10298436.2013.851790 VL - 15 IS - 7 SP - 645-656 SN - 1477-268X KW - traffic load KW - mean profile depth KW - chip seal KW - asphalt surface treatments ER - TY - JOUR TI - Improving Predictability of Construction Project Outcomes through Intentional Management of Indirect Construction Costs AU - Becker, Timothy C. AU - Jaselskis, Edward J. AU - El-Gafy, Mohamed T2 - JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT AB - Indirect construction costs (IDCC) comprise from as little as 10 to 40% or more of the total cost of construction projects, in part depending on the type and nature of the project. Yet, any location in this range represents a significant component of total project costs, which justifies the need to better understand and develop effective practices to estimate, control, and manage IDCC. When IDCC practices are not afforded intentional management and appropriate resources, key project performance outcomes are affected. As its unique contribution to the body of knowledge, this paper operationally defines IDCC, outlines certain innovative IDCC practices, and identifies statistically significant relationships between key IDCC practices and project outcome metrics. Empirical recommendations are premised upon data collected through testimonials, structured interviews, and brainstorming sessions of an extensive set of construction industry professionals. Statistical findings are based upon data collected through 56 one-on-one data-collection interviews with subject matter experts and 47 project-level surveys. Qualitative data were filtered, organized, and aggregated and are technically presented as instructional guidelines. Quantitative data were statistically analyzed and results from this analysis show several significant relationships between IDCC practices and key project outcomes, including a positive correlation between the frequency of IDCC review meetings that included project managers and field supervisors and quality and cost performance. DA - 2014/6/1/ PY - 2014/6/1/ DO - 10.1061/(asce)co.1943-7862.0000845 VL - 140 IS - 6 SP - SN - 1943-7862 ER - TY - JOUR TI - Evaluation of life cycle inventory data for recycling systems AU - Brogaard, Line K. AU - Damgaard, Anders AU - Jensen, Morten B. AU - Barlaz, Morton AU - Christensen, Thomas H. T2 - RESOURCES CONSERVATION AND RECYCLING AB - This paper reviews databases on material recycling (primary as well as secondary production) used in life cycle assessments (LCA) of waste management systems. A total of 366 datasets, from 1980 to 2010 and covering 14 materials, were collected from databases and reports. Totals for CO2-equivalent emissions were compared to illustrate variations in the data. It was hypothesised that emissions from material production and the recycling industry had decreased over time due to increasing regulation, energy costs and process optimisation, but the reported datasets did not reveal such a general trend. Data representing the same processes varied considerably between databases, and proper background information was hard to obtain, which in turn made it difficult to explain the large differences observed. Those differences between the highest and lowest estimated CO2 emissions (equivalents) from the primary production of newsprint, HDPE and glass were 238%, 443% and 452%, respectively. For steel and aluminium the differences were 1761% and 235%, respectively. There is a severe lack of data for some recycled materials; for example, only one dataset existed for secondary cardboard. The study shows that the choice of dataset used to represent the environmental load of a material recycling process and credited emissions from the avoided production of virgin materials is crucial for the outcome of an LCA on waste management. Great care and a high degree of transparency are mandatory, but advice on which datasets to use could not be determined from the study. However, from the gathered data, recycling in general showed lower emission of CO2 per kg material than primary production, so the recycling of materials (considered in this study) is thus beneficial in most cases. DA - 2014/6// PY - 2014/6// DO - 10.1016/j.resconrec.2014.03.011 VL - 87 SP - 30-45 SN - 1879-0658 KW - Life cycle inventory databases KW - Waste recycling KW - Plastics KW - Paper KW - Cardboard KW - Glass KW - Aluminium KW - Steel KW - Life cycle assessment KW - CO2 emission ER - TY - JOUR TI - Characterizing hurricane storm surge behavior in Galveston Bay using the SWAN+ADCIRC model AU - Sebastian, Antonia AU - Proft, Jennifer AU - Dietrich, J. Casey AU - Du, Wei AU - Bedient, Philip B. AU - Dawson, Clint N. T2 - Coastal Engineering AB - The SWAN + ADCIRC shallow-water circulation model, validated for Hurricane Ike (2008), was used to develop five synthetic storm surge scenarios for the upper Texas coast in which wind speed was increased and landfall location was shifted 40 km westward. The Hurricane Ike simulation and the synthetic storms were used to study the maximum water elevations in Galveston Bay, as well as the timing and behavior of surge relative to the hurricane track. Sixteen locations indicative of surge behavior in and around Galveston Bay were chosen to for analysis in this paper. Results show that water surface elevations present in Galveston Bay are dominated by the counterclockwise hurricane winds and that increasing wind speeds by 15% results in approximately 23% (+/− 3%) higher surge. Furthermore, shifting the storm westward causes higher levels of surge in the more populated areas due to more intense, higher shore-normal winds. This research helps to highlight the vulnerability of the upper Texas Gulf Coast to hurricane storm surge and lends insight to storm surge and flood mitigation studies in the Houston–Galveston region. DA - 2014/6// PY - 2014/6// DO - 10.1016/j.coastaleng.2014.03.002 VL - 88 SP - 171-181 J2 - Coastal Engineering LA - en OP - SN - 0378-3839 UR - http://dx.doi.org/10.1016/j.coastaleng.2014.03.002 DB - Crossref KW - SWAN KW - ADCIRC KW - Hurricane KW - Storm surge KW - Forerunner KW - Hydrograph ER - TY - JOUR TI - Characterization of salt cake from secondary aluminum production AU - Huang, Xiao-Lan AU - El Badawy, Amro AU - Arambewela, Mahendranath AU - Ford, Robert AU - Barlaz, Morton AU - Tolaymat, Thabet T2 - JOURNAL OF HAZARDOUS MATERIALS AB - Salt cake is a major waste component generated from the recycling of secondary aluminum processing (SAP) waste. Worldwide, the aluminum industry produces nearly 5 million tons of waste annually and the end-of-life management of these wastes is becoming a challenge in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 39 SAP waste salt cake samples collected from 10 different facilities across the U.S. were determined. The results showed that aluminum (Al), aluminum oxide, aluminum nitride and its oxides, spinel and elpasolite are the dominant aluminum mineral phases in salt cake. The average total Al content was 14% (w/w). The overall percentage of the total leachable Al in salt cake was 0.6% with approximately 80% of the samples leaching at a level less than 1% of the total aluminum content. The extracted trace metal concentrations in deionized water were relatively low (μg L−1 level). The toxicity characteristic leaching procedure (TCLP) was employed to further evaluate leachability and the results indicated that the leached concentrations of toxic metals from salt cake were much lower than the EPA toxicity limit set by USEPA. DA - 2014/5/30/ PY - 2014/5/30/ DO - 10.1016/j.jhazmat.2014.02.035 VL - 273 SP - 192-199 SN - 1873-3336 KW - Aluminum KW - Mineral phase KW - Leachability KW - Salt cake KW - Secondary aluminum production (SAP) KW - Toxicity characteristic leaching procedure (TCLP) ER - TY - JOUR TI - Causes of Time Buffer and Duration Variation in Construction Project Tasks: Comparison of Perception to Reality AU - Russell, Marion M. AU - Hsiang, Simon M. AU - Liu, Min AU - Wambeke, Brad T2 - Journal of Construction Engineering and Management AB - Due to the inherent nature of the construction industry, all construction projects have some amount and type of uncertainty. This uncertainty can lead to variation in project task durations from what was originally planned. As a result, construction personnel compensate for the uncertainty by adding a time buffer to absorb variations in the work plan. For the purpose of this research, a time buffer is defined as the amount of time included in task durations to compensate for uncertainty and to protect against variation. Variation is defined as the difference between the planned and actual task duration. Although previous research acknowledges time buffer additions, the root causes for adding a buffer have not been thoroughly researched. A nationwide survey was administered to project managers, superintendents, and foremen to identify the most severe reasons for adding time buffers to construction task durations. The root causes of variation have been previously identified and are used as the comparison benchmark. Contributions to the body of knowledge include (1) comparing and contrasting the overall most severe causes of time buffers with the most severe causes of duration variation to identify disconnects between the perception of concerns about uncertainty and the reality of what causes task duration variations at different levels of management; and (2) the use of factor analysis to quantitatively identify the underlying structure of time buffer factors. The findings of this research will help construction managers understand what drives the need for buffers in their construction schedules and allow them to focus efforts on strategically addressing the most critical areas of concern and uncertainty. Furthermore, the research reveals similarities and disconnects in the effects of uncertainty on planning and task execution. DA - 2014/6// PY - 2014/6// DO - 10.1061/(asce)co.1943-7862.0000819 VL - 140 IS - 6 SP - 04014016 J2 - J. Constr. Eng. Manage. LA - en OP - SN - 0733-9364 1943-7862 UR - http://dx.doi.org/10.1061/(asce)co.1943-7862.0000819 DB - Crossref ER - TY - JOUR TI - A four phase micro-mechanical model for asphalt mastic modulus AU - Underwood, B. Shane AU - Kim, Y. Richard T2 - Mechanics of Materials AB - In this paper, existing formulations for predicting the stiffening effects of graded aggregate particles at moderate and high concentrations in a viscoelastic matrix (asphalt) are evaluated. These functions encompass dilute, micro-mechanical, and phenomenological solutions, but each is found to produce qualitatively and quantitatively unsatisfactory results at all particle concentrations. These shortcomings are hypothesized result from the inability of these models to consider a third phase of the composite, a physico-chemically influenced layer at the aggregate surface. A model to account for this layer is developed and applied to predict the stiffening of asphalt mastics across a range of volumetric concentrations. The model is found to predict the stiffening responses at moderate concentrations well, but under predicts the responses at the highest concentrations. At these concentrations, particulate contact and internal structure development occurs and provides an additional stiffening mechanism that the four phase model does not account for. The under predictions at these higher concentrations are thus expected and rational. DA - 2014/8// PY - 2014/8// DO - 10.1016/j.mechmat.2014.04.001 VL - 75 SP - 13-33 J2 - Mechanics of Materials LA - en OP - SN - 0167-6636 UR - http://dx.doi.org/10.1016/j.mechmat.2014.04.001 DB - Crossref KW - Rheological properties KW - Analytical modeling KW - Micro-mechanics KW - Asphalt mastic KW - Physico-chemical interaction ER - TY - JOUR TI - Systematic Exploration of Efficient Strategies to Manage Solid Waste in U.S. Municipalities: Perspectives from the Solid Waste Optimization Life-Cycle Framework (SWOLF) AU - Levis, J.W. AU - Barlaz, M.A. AU - DeCarolis, J.F. AU - Ranji Ranjithan, S. T2 - Environmental Science and Technology AB - Solid waste management (SWM) systems must proactively adapt to changing policy requirements, waste composition, and an evolving energy system to sustainably manage future solid waste. This study represents the first application of an optimizable dynamic life-cycle assessment framework capable of considering these future changes. The framework was used to draw insights by analyzing the SWM system of a hypothetical suburban U.S. city of 100 000 people over 30 years while considering changes to population, waste generation, and energy mix and costs. The SWM system included 3 waste generation sectors, 30 types of waste materials, and 9 processes for waste separation, treatment, and disposal. A business-as-usual scenario (BAU) was compared to three optimization scenarios that (1) minimized cost (Min Cost), (2) maximized diversion (Max Diversion), and (3) minimized greenhouse gas (GHG) emissions (Min GHG) from the system. The Min Cost scenario saved $7.2 million (12%) and reduced GHG emissions (3%) relative to the BAU scenario. Compared to the Max Diversion scenario, the Min GHG scenario cost approximately 27% less and more than doubled the net reduction in GHG emissions. The results illustrate how the timed-deployment of technologies in response to changes in waste composition and the energy system results in more efficient SWM system performance compared to what is possible from static analyses. DA - 2014/// PY - 2014/// DO - 10.1021/es500052h VL - 48 IS - 7 SP - 3625 – 3631 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/es500052h DB - Crossref ER - TY - JOUR TI - Power earth auger modification for waste extraction from pit latrines AU - Rogers, Tate Weston AU - Reyes, Francis L., III AU - Beckwith, Walter J. AU - Borden, Robert C. T2 - JOURNAL OF WATER SANITATION AND HYGIENE FOR DEVELOPMENT AB - The extraction auger was developed to meet the need for a low cost, effective method to empty pit latrines in difficult to access locations. The basic design consists of a motor that rotates an auger inside a pipe, lifting waste from a pit and depositing it into containers through a wye fitting at the top of the device. Laboratory testing of the auger showed increases in flow rates with increasing auger rotational speed and waste viscosity. An auger with an external hydraulic drive was capable of lifting dairy waste over 2.5 m, at flow rates of over 125 liters per minute. Field-testing showed the equipment was effective at lifting medium viscosity wastes containing a mixture of liquid and solid material. However, the auger was not effective in removing low viscosity, liquid waste that would flow backward down the auger reducing lifting efficiency. The auger was capable of drilling into dense solid waste, forming a ‘posthole’ in the waste. However, since the dense solid waste would not flow towards the auger intake, actual waste removal from the pit was limited. Improved methods are needed to mix liquid and solid waste in pits prior to removal with the extraction auger or other technologies. DA - 2014/// PY - 2014/// DO - 10.2166/washdev.2013.183 VL - 4 IS - 1 SP - 72-80 SN - 2043-9083 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84896480247&partnerID=MN8TOARS KW - auger KW - pit emptying KW - portable ER - TY - JOUR TI - Potential for metering to help roundabouts manage peak period demands in the United States AU - Hummer, J. E. AU - Milazzo, J. S. AU - Schroeder, B. AU - Salamati, K. T2 - Transportation Research Record DA - 2014/// PY - 2014/// IS - 2402 SP - 56-66 ER - TY - JOUR TI - Performance Assessment of Geosynthetics and Cement as Subgrade Stabilization Measures AU - Cowell, Tim AU - Pyo, Sangchul AU - Gabr, Mohammed A. AU - Borden, Roy H. AU - Kim, K. J. T2 - Geotechnical Testing Journal AB - Work in this paper presents the results of field testing on four instrumented roadway sections constructed on poor subgrade soils and stabilized with select fill, geosynthetics, or cement. Loading was applied using 1000 consecutive truck passes and profile surveying was performed to provide permanent deformation (rutting) data. Peak vertical stresses at the subgrade as well as moisture conditions were also monitored during testing. Results indicated that the deep undercut (31 in./790 mm) with select material backfill section produced the largest cumulative rut depths due to shallow incremental plastic strains induced during each axle pass. The use of a thin Aggregate Base Course (ABC) surface layer (3 in./75 mm) over the select material reduced the rate of rutting. The biaxial geogrid and the high strength geotextile showed a relatively equal performance in all aspects of the study. The cement stabilized section produced a slightly larger average rut depth than the geosynthetically-reinforced sections due to localized areas of pronounced cumulative rutting. However, there were several areas of the soil-cement test section that performed as well as the geosynthetically-reinforced sections. DA - 2014/3/21/ PY - 2014/3/21/ DO - 10.1520/gtj20120206 VL - 37 IS - 3 SP - 20120206 J2 - Geotech. Test. J. LA - en OP - SN - 0149-6115 UR - http://dx.doi.org/10.1520/GTJ20120206 DB - Crossref KW - cement KW - geosynthetics KW - subgrade KW - undercut KW - field KW - rutting ER - TY - JOUR TI - Modeling Seasonal Heteroscedasticity in Vehicular Traffic Condition Series Using a Seasonal Adjustment Approach AU - Shi, Guogang AU - Guo, Jianhua AU - Huang, Wei AU - Williams, Billy M. T2 - Journal of Transportation Engineering AB - Heteroscedasticity modeling in transportation engineering is primarily conducted in short-term traffic condition forecasting to generate time varying prediction intervals around the point forecasts through quantitatively predicting the conditional variance of traffic condition series. Until recently, the generalized autoregressive conditional heteroscedasticity (GARCH) model and the stochastic volatility model have been two major approaches adopted from the field of financial time series analysis for traffic heteroscedasticity modeling. In this paper, recognizing the pronounced seasonal pattern in traffic condition data, a simple seasonal adjustment approach is explored for modeling seasonal heteroscedasticity in traffic-flow series, and four types of seasonal adjustment factors are proposed with respect to daily or weekly patterns. Using real-world traffic-flow data collected from highway systems in the United Kingdom and the United States, the proposed seasonal adjustment approach is implemented and validated. Empirical results show that the proposed model can effectively capture and hence model the seasonal heteroscedasticity in traffic-flow series. In addition, through a comparison with the conventional GARCH model, the proposed approach is shown to consistently generate improved performances in terms of prediction interval construction. Potential applications are discussed to explore the value of heteroscedasticity modeling in transportation engineering studies. DA - 2014/5// PY - 2014/5// DO - 10.1061/(ASCE)TE.1943-5436.0000656 VL - 140 IS - 5 SP - 04014012 J2 - J. Transp. Eng. LA - en OP - SN - 0733-947X 1943-5436 UR - http://dx.doi.org/10.1061/(ASCE)TE.1943-5436.0000656 DB - Crossref KW - Seasonal effect KW - Heteroscedasticity modeling KW - Short-term traffic condition forecasting KW - Generalized autoregressive conditional heteroscedasticity (GARCH) KW - Time series analysis KW - Seasonal autoregressive integrated moving average (SARIMA) ER - TY - JOUR TI - Method for Modeling Driving Cycles, Fuel Use, and Emissions for Over Snow Vehicles AU - Hu, Jiangchuan AU - Frey, H. Christopher AU - Sandhu, Gurdas S. AU - Graver, Brandon M. AU - Bishop, Gary A. AU - Schuchmann, Brent G. AU - Ray, John D. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - As input to a winter use plan, activity, fuel use, and tailpipe exhaust emissions of over snow vehicles (OSV), including five snow coaches and one snowmobile, were measured on a designated route in Yellowstone National Park (YNP). Engine load was quantified in terms of vehicle specific power (VSP), which is a function of speed, acceleration, and road grade. Compared to highway vehicles, VSP for OSVs is more sensitive to rolling resistance and less sensitive to aerodynamic drag. Fuel use rates increased linearly (R2>0.96) with VSP. For gasoline-fueled OSVs, fuel-based emission rates of carbon monoxide (CO) and nitrogen oxides (NOx) typically increased with increasing fuel use rate, with some cases of very high CO emissions. For the diesel OSVs, which had selective catalytic reduction and diesel particulate filters, fuel-based NOx and particulate matter (PM) emission rates were not sensitive to fuel flow rate, and the emission controls were effective. Inter vehicle variability in cycle average fuel use and emissions rates for CO and NOx was substantial. However, there was relatively little inter-cycle variation in cycle average fuel use and emission rates when comparing driving cycles. Recommendations are made regarding how real-world OSV activity, fuel use, and emissions data can be improved. DA - 2014/7/15/ PY - 2014/7/15/ DO - 10.1021/es501164j VL - 48 IS - 14 SP - 8258-8265 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84904409293&partnerID=MN8TOARS ER - TY - JOUR TI - Mechanistic evaluation of cracking in in-service asphalt pavements AU - Park, Hong Joon AU - Eslaminia, Mehran AU - Kim, Y. Richard T2 - MATERIALS AND STRUCTURES DA - 2014/8// PY - 2014/8// DO - 10.1617/s11527-014-0307-6 VL - 47 IS - 8 SP - 1339-1358 SN - 1871-6873 KW - Asphalt pavement KW - Top-down cracking KW - Bottom-up cracking KW - Layered viscoelastic pavement analysis for critical distresses (LVECD) program ER - TY - JOUR TI - Launching a Career and a Way to Make a Difference AU - Rogers, Tate W. T2 - JOURNAL AMERICAN WATER WORKS ASSOCIATION AB - Field work was conducted on a pit‐emptying system in South Africa after a proposal by the author received funding from the Bill and Melinda Gates Foundation (BMGF). BMGF was looking for new ideas to meet the needs of more than 2.5 billion people without access to proper sanitation in the developing world. DA - 2014/2// PY - 2014/2// DO - 10.5942/jawwa.2014.106.0041 VL - 106 IS - 2 SP - 31-33 SN - 1551-8833 ER - TY - JOUR TI - In-use measurement of the activity, fuel use, and emissions of front-loader refuse trucks AU - Sandhu, Gurdas S. AU - Frey, H. Christopher AU - Bartelt-Hunt, Shannon AU - Jones, Elizabeth T2 - ATMOSPHERIC ENVIRONMENT AB - Field measurements were made for six front-loader refuse trucks for over 560 miles (901 km) and 47 h of operation using a portable emissions measurement system, electronic control unit data logger, and global positioning system receivers. Daily activity, fuel use rates, and emission rates are quantified in terms of operating mode bins defined by the U.S. Environmental Protection Agency for the MOVES emission factor model. On average, 44 (±4) percent of time was spent at idle, 5 (±1) percent braking or decelerating, 11 (±2) percent coasting, 23 (±3) percent cruising or accelerating at low speed (up to 25 mph, 40.2 kmph), 10 (±2) percent cruising or accelerating at moderate speed (25–50 mph, 40.2 to 80.4 kmph), and 7 (±3) percent cruising or accelerating at high speed (50 mph, 80.4 kmph or higher). Fuel use and emission rates varied among operating modes by factors of 6–24. The estimated daily activity cycle average fuel economy ranges from 2.3 to 3.2 mpg (0.98–1.4 kmpl). The PM emission rates for trucks with diesel particulate filters are 98 percent lower compared to those without. Variation in truck weight lead to differences in average fuel use and emission rates of 20 percent or less, except for hydrocarbons. The variation in the empirically-based daily activity cycle average rates were highly correlated with MOVES estimates, except for hydrocarbons. The data collected here are useful for quantifying daily activity specific to front-loaders, and for developing fuel use and emission estimates and models for this type of vehicle. DA - 2014/8// PY - 2014/8// DO - 10.1016/j.atmosenv.2014.04.036 VL - 92 SP - 557-565 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84901001305&partnerID=MN8TOARS KW - Diesel refuse truck KW - Duty cycle KW - Exhaust emissions KW - Nitrogen oxides KW - Particulate matter KW - MOVES ER - TY - JOUR TI - Improving Groundwater Predictions Utilizing Seasonal Precipitation Forecasts from General Circulation Models Forced with Sea Surface Temperature Forecasts AU - Almanaseer, Naser AU - Sankarasubramanian, A. AU - Bales, Jerad T2 - JOURNAL OF HYDROLOGIC ENGINEERING AB - Recent studies have found a significant association between climatic variability and basin hydroclimatology, particularly groundwater levels, over the southeast United States. The research reported in this paper evaluates the potential in developing 6-month-ahead groundwater-level forecasts based on the precipitation forecasts from ECHAM 4.5 General Circulation Model Forced with Sea Surface Temperature forecasts. Ten groundwater wells and nine streamgauges from the USGS Groundwater Climate Response Network and Hydro-Climatic Data Network were selected to represent groundwater and surface water flows, respectively, having minimal anthropogenic influences within the Flint River Basin in Georgia, United States. The writers employ two low-dimensional models [principle component regression (PCR) and canonical correlation analysis (CCA)] for predicting groundwater and streamflow at both seasonal and monthly timescales. Three modeling schemes are considered at the beginning of January to predict winter (January, February, and March) and spring (April, May, and June) streamflow and groundwater for the selected sites within the Flint River Basin. The first scheme (model 1) is a null model and is developed using PCR for every streamflow and groundwater site using previous 3-month observations (October, November, and December) available at that particular site as predictors. Modeling schemes 2 and 3 are developed using PCR and CCA, respectively, to evaluate the role of precipitation forecasts in improving monthly and seasonal groundwater predictions. Modeling scheme 3, which employs a CCA approach, is developed for each site by considering observed groundwater levels from nearby sites as predictands. The performance of these three schemes is evaluated using two metrics (correlation coefficient and relative RMS error) by developing groundwater-level forecasts based on leave-five-out cross-validation. Results from the research reported in this paper show that using precipitation forecasts in climate models improves the ability to predict the interannual variability of winter and spring streamflow and groundwater levels over the basin. However, significant conditional bias exists in all the three modeling schemes, which indicates the need to consider improved modeling schemes as well as the availability of longer time-series of observed hydroclimatic information over the basin. DA - 2014/1/1/ PY - 2014/1/1/ DO - 10.1061/(asce)he.1943-5584.0000776 VL - 19 IS - 1 SP - 87-98 SN - 1943-5584 KW - Groundwater management KW - Water levels KW - Climates KW - Stochastic models KW - Predictions KW - Groundwater KW - Forecasts KW - Hydroclimatology KW - Climate ER - TY - JOUR TI - Digital image correlation techniques to investigate strain fields and cracking phenomena in asphalt materials AU - Buttlar, William G. AU - Hill, Brian C. AU - Kim, Y. Richard AU - Kutay, M. Emin AU - Millien, Anne AU - Montepara, Antonio AU - Paulino, Glaucio H. AU - Petit, Christophe AU - Pop, Ion Octavian AU - Romeo, Elena AU - Roncella, Riccardo AU - Safavizadeh, Seyed Amirshayan AU - Tebaldi, Gabriele AU - Wargo, Andrew T2 - MATERIALS AND STRUCTURES DA - 2014/8// PY - 2014/8// DO - 10.1617/s11527-014-0362-z VL - 47 IS - 8 SP - 1373-1390 SN - 1871-6873 KW - Asphalt mixture KW - Digital image correlation KW - Optical flow KW - Mode I fracture KW - Mode II fracture KW - Debonding ER - TY - JOUR TI - Complex Adaptive Systems Framework to Assess Supply-Side and Demand-Side Management for Urban Water Resources AU - Kanta, Lufthansa AU - Zechman, Emily T2 - Journal of Water Resources Planning and Management AB - The availability of water resources in many urbanizing areas is the emergent property of the adaptive interactions among consumers, policy, and the hydrologic cycle. As water availability becomes more stressed, public officials often implement restrictions on water use, such as bans on outdoor watering. Consumers are influenced by policy and the choices of other consumers to select water-conservation technologies and practices, which aggregate as the demand on available water resources. Policy and behavior choices affect the availability of water for future use as reservoirs are depleted or filled. This research posited urban water supply as a complex adaptive system (CAS) by coupling a stochastic consumer demand model and a water supply model within an agent-based modeling (ABM) framework. Public officials were simulated as agents to choose water conservation strategies and interbasin transfer strategies, and consumers were simulated as agents, influenced by various conservation-based programs to select water conservation technologies and behaviors, and correspondingly update their individual demand models. A water supply reservoir was simulated to receive rainfall from the contributing watershed and to supply the demands of consumer agents. The ABM framework was applied to an illustrative urban case study. A set of scenarios was developed to represent moderate and strong water conservation strategies, and was simulated for a long-term precipitation record to evaluate the sustainability of water conservation practices. DA - 2014/1// PY - 2014/1// DO - 10.1061/(asce)wr.1943-5452.0000301 VL - 140 IS - 1 SP - 75-85 J2 - J. Water Resour. Plann. Manage. LA - en OP - SN - 0733-9496 1943-5452 UR - http://dx.doi.org/10.1061/(asce)wr.1943-5452.0000301 DB - Crossref KW - Adaptive systems KW - Water management KW - Droughts KW - Pumps KW - Urban areas KW - Agent-based modeling KW - Complex adaptive systems analysis KW - Water conservation KW - Drought management plan KW - Adaptive pumping KW - Demand-side management KW - Supply-side management ER - TY - JOUR TI - An optimized design of network arch bridge using global optimization algorithm AU - Islam, N. AU - Rana, S. AU - Ahsan, R. AU - Ghani, S. N. T2 - Advances in Structural Engineering DA - 2014/// PY - 2014/// VL - 17 IS - 2 SP - 197-210 ER - TY - JOUR TI - A Monitoring Network Design Procedure for Three-Dimensional (3D) Groundwater Contaminant Source Identification AU - Jin, Xin AU - Ranjithan, Ranji S. AU - Mahinthakumar, G. T2 - ENVIRONMENTAL FORENSICS AB - Finding the location and concentration of contaminant sources is an important step in groundwater remediation and management. This discovery typically requires the solution of an inverse problem. This inverse problem can be formulated as an optimization problem where the objective function is the sum of the square of the errors between the observed and predicted values of contaminant concentration at the observation wells. Studies show that the source identification accuracy is dependent on the observation locations (i.e., network geometry) and frequency of sampling; thus, finding a set of optimal monitoring well locations is very important for characterizing the source. The objective of this study is to propose a sensitivity-based method for optimal placement of monitoring wells by incorporating two uncertainties: the source location and hydraulic conductivity. An optimality metric called D-optimality in combination with a distance metric, which tends to make monitoring locations as far apart from each other as possible, is developed for finding optimal monitoring well locations for source identification. To address uncertainty in hydraulic conductivity, an integration method of multiple well designs is proposed based on multiple hydraulic conductivity realizations. Genetic algorithm is used as a search technique for this discrete combinatorial optimization problem. This procedure was applied to a hypothetical problem based on the well-known Borden Site data in Canada. The results show that the criterion-based selection proposed in this paper provides improved source identification performance when compared to uniformly distributed placement of wells. DA - 2014/1/2/ PY - 2014/1/2/ DO - 10.1080/15275922.2013.873095 VL - 15 IS - 1 SP - 78-96 SN - 1527-5930 KW - genetic algorithm KW - monitoring well network KW - Groundwater modeling KW - D-optimality ER - TY - JOUR TI - Wireless Crack Detection in Concrete Elements Using Conductive Surface Sensors and Radio Frequency Identification Technology AU - Pour-Ghaz, Mohammad AU - Barrett, Timothy AU - Ley, Tyler AU - Materer, Nicholas AU - Apblett, Allen AU - Weiss, Jason T2 - JOURNAL OF MATERIALS IN CIVIL ENGINEERING AB - This paper describes the results of an experimental study that uses radio frequency identification (RFID) technology to detect cracking in concrete elements. A RFID-based sensor is used to monitor the change in electrical resistance that occurs in conductive materials applied to the surface of the concrete. When the concrete substrate is strained, the conductive material at the surface is stretched, and its electrical resistance increases. If the concrete substrate is strained to the point where it cracks, the conductive material at the surface also cracks, causing its electrical resistance to increase by orders of magnitude. This paper describes how this increase in electrical resistance attributable to cracking can be detected wirelessly by RFID technology. To experimentally illustrate the application of this technology, an RFID-based sensor and conductive surface materials are used to detect cracking in the restrained ring test. The experimental results indicate that this technology can be easily implemented and successfully used for wireless crack detection in concrete and reinforced concrete members. The technology that is described in this paper is not limited to the laboratory environment and can be easily extended to field applications. DA - 2014/5/1/ PY - 2014/5/1/ DO - 10.1061/(asce)mt.1943-5533.0000891 VL - 26 IS - 5 SP - 923-929 SN - 1943-5533 KW - Cracking KW - Conductive surface sensor KW - Sensing skin KW - Concrete KW - Wireless sensing KW - Ring test KW - Shrinkage KW - RFID KW - Health monitoring KW - Shrinkage cracking ER - TY - JOUR TI - Systems Biology of Lignin Biosynthesis in Populus trichocarpa: Heteromeric 4-Coumaric Acid: Coenzyme A Ligase Protein Complex Formation, Regulation, and Numerical Modeling AU - Chen, Hsi-Chuan AU - Song, Jina AU - Wang, Jack P. AU - Lin, Ying-Chung AU - Ducoste, Joel AU - Shuford, Christopher M. AU - Liu, Jie AU - Li, Quanzi AU - Shi, Rui AU - Nepomuceno, Angelito AU - Isik, Fikret AU - Muddiman, David C. AU - Williams, Cranos AU - Sederoff, Ronald R. AU - Chiang, Vincent L. T2 - PLANT CELL AB - As a step toward predictive modeling of flux through the pathway of monolignol biosynthesis in stem differentiating xylem of Populus trichocarpa, we discovered that the two 4-coumaric acid:CoA ligase (4CL) isoforms, 4CL3 and 4CL5, interact in vivo and in vitro to form a heterotetrameric protein complex. This conclusion is based on laser microdissection, coimmunoprecipitation, chemical cross-linking, bimolecular fluorescence complementation, and mass spectrometry. The tetramer is composed of three subunits of 4CL3 and one of 4CL5. 4CL5 appears to have a regulatory role. This protein–protein interaction affects the direction and rate of metabolic flux for monolignol biosynthesis in P. trichocarpa. A mathematical model was developed for the behavior of 4CL3 and 4CL5 individually and in mixtures that form the enzyme complex. The model incorporates effects of mixtures of multiple hydroxycinnamic acid substrates, competitive inhibition, uncompetitive inhibition, and self-inhibition, along with characteristic of the substrates, the enzyme isoforms, and the tetrameric complex. Kinetic analysis of different ratios of the enzyme isoforms shows both inhibition and activation components, which are explained by the mathematical model and provide insight into the regulation of metabolic flux for monolignol biosynthesis by protein complex formation. DA - 2014/3// PY - 2014/3// DO - 10.1105/tpc.113.119685 VL - 26 IS - 3 SP - 876-893 SN - 1532-298X UR - https://doi.org/10.1105/tpc.113.119685 ER - TY - JOUR TI - Systematic uncertainty reduction strategies for developing streamflow forecasts utilizing multiple climate models and hydrologic models AU - Singh, Harminder AU - Sankarasubramanian, A. T2 - WATER RESOURCES RESEARCH AB - Recent studies show that multimodel combinations improve hydroclimatic predictions by reducing model uncertainty. Given that climate forecasts are available from multiple climate models, which could be ingested with multiple watershed models, what is the best strategy to reduce the uncertainty in streamflow forecasts? To address this question, we consider three possible strategies: (1) reduce the input uncertainty first by combining climate models and then use the multimodel climate forecasts with multiple watershed models (MM-P), (2) ingest the individual climate forecasts (without multimodel combination) with various watershed models and then combine the streamflow predictions that arise from all possible combinations of climate and watershed models (MM-Q), (3) combine the streamflow forecasts obtained from multiple watershed models based on strategy (1) to develop a single streamflow prediction that reduces uncertainty in both climate forecasts and watershed models (MM-PQ). For this purpose, we consider synthetic schemes that generate streamflow and climate forecasts, for comparing the performance of three strategies with the true streamflow generated by a given hydrologic model. Results from the synthetic study show that reducing input uncertainty first (MM-P) by combining climate forecasts results in reduced error in predicting the true streamflow compared to the error of multimodel streamflow forecasts obtained by combining streamflow forecasts from all-possible combination of individual climate model with various hydrologic models (MM-Q). Since the true hydrologic model structure is unknown, it is desirable to consider MM-PQ as an alternate choice that reduces both input uncertainty and hydrologic model uncertainty. Application on two watersheds in NC also indicates that reducing the input uncertainty first is critical before reducing the hydrologic model uncertainty. DA - 2014/2// PY - 2014/2// DO - 10.1002/2013wr013855 VL - 50 IS - 2 SP - 1288-1307 SN - 1944-7973 KW - Model Uncertainty KW - Model Combination KW - Streamflow Forecasts KW - Climate Forecasts ER - TY - JOUR TI - Sociotechnical risk assessment for water distribution system contamination threats AU - Rasekh, Amin AU - Shafiee, M. Ehsan AU - Zechman, Emily AU - Brumbelow, Kelly T2 - Journal of Hydroinformatics AB - Water distribution systems (WDS) are vulnerable to contaminants, and systematic risk assessment can provide valuable information for assisting threat management. Contamination events are sociotechnical systems, in which the interactions among consumers and water infrastructure may generate unpredicted public health consequences. This research develops a sociotechnical risk assessment framework that simulates the dynamics of a contamination event by coupling an agent-based modeling (ABM) framework with Monte Carlo simulation (MCS), genetic algorithm (GA) optimization, and a multi-objective GA. The ABM framework couples WDS simulation with agents to represent consumers in a virtual city. MCS is applied to estimate the uncertainty in human exposure, based on probabilistic models of event attributes. A GA approach is used to identify critical contamination events by maximizing risk, and a multi-objective approach explores the trade-off between consequence and occurrence probabilities. Results that are obtained using the sociotechnical approach are compared with results obtained using a conventional engineering model. The sociotechnical approach removes assumptions that have been used in engineering analysis about the static, homogeneous, and stationary behaviors of consumers, and results demonstrate new insight about the impacts of these actions and interactions on the public health consequences of contamination events. DA - 2014/5// PY - 2014/5// DO - 10.2166/hydro.2013.023 VL - 16 IS - 3 SP - 531-549 J2 - J Hydroinform LA - en OP - SN - 1464-7141 1465-1734 UR - http://dx.doi.org/10.2166/hydro.2013.023 DB - Crossref KW - complex adaptive system KW - contamination KW - evolutionary algorithm KW - risk assessment KW - sociotechnical KW - water distribution system ER - TY - JOUR TI - On crystal shear, lattice rotation and constraint stress in (110) channel die compression: rate-independent and viscoplastic analyses and predictions compared AU - Havner, Kerry S. T2 - PHILOSOPHICAL MAGAZINE AB - AbstractRate-independent crystal plasticity theory and a classic viscoplastic power-law are investigated, contrasted and compared for finite deformation analysis of fcc crystals in channel die compression, including full consideration of lattice straining. Both experiment-based anisotropic and isotropic (Taylor) hardenings are evaluated in rate-independent theory; and an unlimited range of power-law exponent n is considered in viscoplasticity. The focus is on predictions of lateral constraint stress, lattice rotation and crystal shear, and their comparison with experiment. General elastic-plastic equations (for both theories) are given for the range of unstable lattice orientations in (1 1 0) compression (‘range I’) and evaluated before and after a finite rotation of the lattice about the load axis. Equations also are given and evaluated for the ‘Brass’ orientation. It is shown that the theories can be in close agreement at the onset of finite deformation in range I, but that viscoplasticity gives results (for any n) after finite rotation that are in sharp contrast to rate-independent theory. The latter’s predictions for crystal shear and lattice rotation are in good to very good agreement with finite deformation experiments on aluminium and copper. The inclusion of lattice elasticity is found to have a negligible effect in range I. In contrast, for finite deformation in the stable Brass orientation, elastic-viscoplastic theory can be made to agree very closely with rate-independent theory and with experiment.Keywords: channel die compressionfinite deformationfcc crystalsrate-independent elastic-plasticelastic-viscoplasticView correction statement:Corrigendum AcknowledgementI thank my colleague Dr Jie Yu for her numerical solution of the differential equation for anisotropic constraint stress in Al, range I and for the final, computer-generated Figures 3 and 4. DA - 2014/// PY - 2014/// DO - 10.1080/14786435.2014.899441 VL - 94 IS - 17 SP - 1924-1955 SN - 1478-6443 KW - channel die compression KW - finite deformation KW - fcc crystals KW - rate-independent elastic-plastic KW - elastic-viscoplastic ER - TY - JOUR TI - Multisite stochastic weather generation using cluster analysis and k-nearest neighbor time series resampling AU - Caraway, Nina Marie AU - McCreight, James Lucian AU - Rajagopalan, Balaji T2 - JOURNAL OF HYDROLOGY AB - We offer a multisite stochastic weather generator which is an enhancement to the traditional K-nearest neighbor resampling approach. The proposed weather generator consists of three main components: (i) Clustering of spatial locations into homogeneous regions based on a selected attribute (precipitation), (ii) Markov transition probabilities (either on individual clusters or) over all eight wet/dry states of the three-cluster system to model the spatial precipitation occurrence, and (iii) the traditional K-NN weather generator applied to each cluster-averaged weather time series to generate weather sequences at all the desired locations. The weather generator is also adapted to conditional simulation based on seasonal forecasts involving modification of the third component. We demonstrate the utility of this approach by simulating daily weather sequences at 66 locations in the 25,000 sq. mile San Juan River watershed, a tributary of the Colorado River, USA. As the classic K-NN approach involves sampling from a domain-averaged feature vector, all daily weather is simulated across all locations simultaneously. While this preserves the joint statistics, it tends to be biased to the extremes on any given day. Our cluster-based approach offers the ability to account for regional persistence and spatial non-stationarities. In our comparison of the methods, the cluster-based approach demonstrates some improvement over the classic approach, particularly when modeling winter precipitation, reproducing spells, and in dry years. While this particular application shows only marginal improvement, we offer cluster-based resampling as a novel methodological contribution. DA - 2014/1/16/ PY - 2014/1/16/ DO - 10.1016/j.jhydrol.2013.10.054 VL - 508 SP - 197-213 SN - 1879-2707 KW - Weather generation KW - Stochastic KW - Nonparametric KW - Multisite KW - Colorado River KW - San Juan River ER - TY - JOUR TI - Fiber-Based Modeling of Circular Reinforced Concrete Bridge Columns AU - Feng, Yuhao AU - Kowalsky, Mervyn J. AU - Nau, James M. T2 - JOURNAL OF EARTHQUAKE ENGINEERING AB - This article presents the application of fiber-based analysis to predict the nonlinear response of reinforced concrete bridge columns. Specifically considered are predictions of overall force-deformation hysteretic response and strain gradients in plastic hinge regions. This article discusses the relative merits of force-based and displacement-based fiber elements, and proposes a technique for prediction of nonlinear strain distribution based on the modified compression field theory. The models are compared with static and dynamic test data and recommendations are made for fiber-based modeling of RC bridge columns. DA - 2014/// PY - 2014/// DO - 10.1080/13632469.2014.904254 VL - 18 IS - 5 SP - 714-734 SN - 1559-808X KW - Fiber KW - Reinforced Concrete KW - Strain Penetration KW - Tension Shift KW - Earthquake ER - TY - JOUR TI - Bio-bricks: Biologically cemented sandstone bricks AU - Bernardi, D. AU - DeJong, J. T. AU - Montoya, B. M. AU - Martinez, B. C. T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The cementation of sand into sandstone through microbial activity is a novel technology with a wide range of possible applications. The cementation process involves the introduction of bacteria and nutrients to sand, and through bacterial processes calcite precipitation binds particles together, ultimately creating a sandstone material. This technology could provide a new, more sustainable building material in the form of “bio-bricks”. This paper describes the treatment technique as well as results from testing after brick manufacturing. Bricks were tested to determine compression (p-wave) wave velocity, unconfined compression strength, and calcite concentration. P-wave velocity, stiffness, strength, and calcite content of bio-bricks all increase with further treatment of bacteria and cementation media. Results show that bio-bricks can have strengths ranging from 1 MPa to 2 MPa. Bio-bricks are comparable in terms of stress and stiffness to bricks prepared with the more conventional cement and hydraulic lime additives. DA - 2014/3/31/ PY - 2014/3/31/ DO - 10.1016/j.conbuildmat.2014.01.019 VL - 55 SP - 462-469 SN - 1879-0526 KW - Bricks KW - Calcite precipitation KW - Microbially induced calcite precipitation KW - Compression strength KW - Stiffness ER - TY - JOUR TI - Numerical studies on the effect of temperature on the unsaturated hydraulic response of geotextiles AU - Bahador, M. AU - Evans, T.M. AU - Gabr, M.A. T2 - Computers and Geotechnics AB - A series of coupled thermo-hydraulic simulations were performed on a soil–geotextile column to understand the effect of temperature on suction distribution throughout the soil column and on the hydraulic performance of the geotextile as a drainage/capillary barrier layer. Two different constant temperatures of 0 °C and 38 °C and a temperature gradient of 4 °C along the column were modeled. Changing the temperature from 0 °C to 38 °C did not have a significant effect on the suction head distribution in the soil–geotextile column. The temperature gradient resulted in appreciable thermal vapor flow and changes in suction head and hydraulic conductivity of the geotextile. During drainage, the temperature gradient and lower temperature at the top of the column increased suction in the geotextile and its ability to function as a capillary barrier. During capillary rise, the temperature gradient and lower temperature at the top of the column decreased the suction in the geotextile and its ability to function as a capillary barrier. Changing the direction of the thermal gradient reversed the water vapor flow direction and its effect on the suction in the geotextile. A temperature gradient did not have a noticeable effect on the suction head of the geotextile when positive pore pressure was developed in the geotextile and adjacent soil during drainage. DA - 2014/6// PY - 2014/6// DO - 10.1016/j.compgeo.2014.03.010 VL - 59 SP - 161-170 ER - TY - JOUR TI - Municipal solid waste conversion to transportation fuels: a life-cycle estimation of global warming potential and energy consumption AU - Pressley, Phillip N. AU - Aziz, Tarek N. AU - DeCarolis, Joseph F. AU - Barlaz, Morton A. AU - He, Feng AU - Li, Fanxing AU - Damgaard, Anders T2 - JOURNAL OF CLEANER PRODUCTION AB - This paper utilizes life cycle assessment (LCA) methodology to evaluate the conversion of U.S. municipal solid waste (MSW) to liquid transportation fuels via gasification and Fischer-Tropsch (FT). The model estimates the cumulative energy demand and global warming potential (GWP) associated with the conversion of 1 Mg (1 Mg = 1000 kg) of MSW delivered to the front gate of a refuse-derived fuel (RDF) facility into liquid transportation fuels. In addition, net energy production is reported to quantify system performance. The system is expanded to include substituted electricity and fuel. Under a set of default assumptions, the model estimates that 1 Mg of MSW entering the RDF facility yields 123 L of gasoline, 57 L of diesel, 79 kg of other FT products, and 193 kWh of gross electricity production. For each Mg of MSW, the conversion process consumes 4.4 GJ of primary energy while creating fuels and electricity with a cumulative energy content of 10.8 GJ. Across a range of waste compositions, the liquid fuels produced by gasification and FT processing resulted in a net GWP ranging from −267 to −144 kg CO2e per Mg MSW, including offsets for conventional electricity and fuel production. The energy requirement associated with syngas compression for FT processing was significant and resulted in high levels of process-related GWP. The model demonstrates that an increased biogenic MSW fraction, assumed to be carbon neutral, reduced the GWP. However, a greater GWP reduction could be obtained through reduced FT pressure requirements, increased gas reaction rates, or a less carbon intensive power mix. DA - 2014/5/1/ PY - 2014/5/1/ DO - 10.1016/j.jclepro.2014.02.041 VL - 70 SP - 145-153 SN - 1879-1786 KW - Municipal solid waste KW - Gasification KW - Fischer-Tropsch KW - Life cycle assessment KW - Liquid fuels ER - TY - JOUR TI - Global Sea Surface Temperature Forecasts Using an Improved Multimodel Approach AU - Zaved, Mohammad AU - Khan, Kaiser AU - Mehrotra, Rajeshwar AU - Sharma, Ashish AU - Sankarasubramanian, A. T2 - JOURNAL OF CLIMATE AB - Abstract With the availability of hindcasts or real-time forecasts from a number of coupled climate models, multimodel ensemble forecasting systems have gained popularity in recent years. However, many models share similar physics or modeling processes, which may lead to similar (or strongly correlated) forecasts. Assigning equal weights to each model in space and time may result in a biased forecast with narrower confidence limits than is appropriate. Although methods for combining forecasts that take into consideration differences in model accuracy over space and time exist, they suffer from a lack of consideration of the intermodel dependence that may exist. This study proposes an approach that considers the dependence among models while combining multimodel ensemble forecast. The approach is evaluated by combining sea surface temperature (SST) forecasts from five climate models for the period 1960–2005. The variable of interest, the monthly global sea surface temperature anomalies (SSTA) at a 5° × 5° latitude–longitude grid, is predicted three months in advance using the proposed algorithm. Results indicate that the proposed approach offers consistent and significant improvements for all the seasons over the majority of grid points compared to the case in which the dependence among the models is ignored. Consequently, the proposed approach of combining multiple models, taking into account the interdependence that exists, provides an attractive strategy to develop improved SST forecasts. DA - 2014/5// PY - 2014/5// DO - 10.1175/jcli-d-13-00486.1 VL - 27 IS - 10 SP - 3505-3515 SN - 1520-0442 KW - Statistical techniques KW - Seasonal forecasting KW - Statistical forecasting ER - TY - JOUR TI - Effect of Dynamic Loading and Environmental Conditions on the Bond between CFRP and Steel: State-of-the-Art Review AU - Zhao, Xiao-Ling AU - Bai, Yu AU - Al-Mahaidi, Riadh AU - Rizkalla, Sami T2 - JOURNAL OF COMPOSITES FOR CONSTRUCTION AB - Carbon fiber reinforced polymer (CFRP) has great potential in strengthening steel structures and the bond between CFRP and steel is a critical issue in the strengthening technique. State-of-the-art reviews have been reported in the literature on the bond behavior between CFRP and steel under static loading at ambient temperature. However, steel structures are often subjected to dynamic loading and harsh environment conditions, and the bond between CFRP and steel may be affected by these conditions. This paper presents a state-of-the-art review on the effects of dynamic loading (e.g., fatigue, impact, and earthquake) and environmental conditions (e.g., subzero temperatures, elevated temperatures, sea water, and ultraviolet light) on the bond between CFRP and steel. The combined effect of applied loading and environmental conditions is also included. Directions for future research are indicated and a comprehensive reference list is provided. DA - 2014/6// PY - 2014/6// DO - 10.1061/(asce)cc.1943-5614.0000419 VL - 18 IS - 3 SP - SN - 1943-5614 KW - Bond KW - Carbon fiber reinforced polymer KW - Dynamic loading KW - Environmental conditions KW - Steel structures ER - TY - JOUR TI - Design of FRP-Strengthened Infill Masonry Walls Subjected to Out-of-Plane Loading AU - Lunn, D. AU - Rizkalla, S. T2 - Journal of Composites for Construction AB - Fiber-reinforced polymer (FRP) strengthening systems for infill-masonry walls are typically designed to resist flexural stresses caused by out-of-plane pressure. Previous research has shown that there are potential premature failure mechanisms caused by shear sliding of the infill, which could reduce the effectiveness of the strengthening system. Current design guidelines for strengthening of masonry walls with FRP do not include guidelines for infill-masonry. This paper presents a rational approach for the design and analysis of FRP-strengthened infill-masonry walls subjected to out-of-plane loading, including the effect of using FRP end anchorage. The approach is based on consideration of four potential mechanisms: arching, shear sliding, debonding of the FRP in the overlap region, and failure of the FRP end-anchorage system. The predictions based on the proposed rational approach agree well with the measured values from two experimental programs. DA - 2014/6// PY - 2014/6// DO - 10.1061/(asce)cc.1943-5614.0000412 VL - 18 IS - 3 SP - SN - 1943-5614 KW - Fiber-reinforced polymer KW - Walls KW - Masonry KW - Rehabilitation KW - Composite materials KW - Anchorages KW - Lateral pressure KW - Design ER - TY - JOUR TI - Chemical Changes during Anaerobic Decomposition of Hardwood, Softwood, and Old Newsprint under Mesophilic and Thermophilic Conditions AU - Cruz, Florentino B. AU - Yelle, Daniel J. AU - Gracz, Hanna S. AU - Barlaz, Morton A. T2 - JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY AB - The anaerobic decomposition of plant biomass is an important aspect of global organic carbon cycling. While the anaerobic metabolism of cellulose and hemicelluloses to methane and carbon dioxide are well-understood, evidence for the initial stages of lignin decomposition is fragmentary. The objective of this study was to look for evidence of chemical transformations of lignin in woody tissues [hardwood (HW), softwood (SW), and old newsprint (ONP)] after anaerobic decomposition using Klason and acid-soluble lignin, CuO oxidation, and 2D NMR. Tests were conducted under mesophilic and thermophilic conditions, and lignin associations with structural carbohydrates are retained. For HW and ONP, the carbon losses could be attributed to cellulose and hemicelluloses, while carbon loss in SW was attributable to an uncharacterized fraction (e.g., extractives etc.). The 2D NMR and chemical degradation methods revealed slight reductions in β-O-4 linkages for HW and ONP, with no depolymerization of lignin in any substrate. DA - 2014/7/9/ PY - 2014/7/9/ DO - 10.1021/jf501653h VL - 62 IS - 27 SP - 6362-6374 SN - 1520-5118 KW - anaerobic decomposition KW - CuO oxidation KW - lignin KW - HSQC KW - NMR ER - TY - JOUR TI - Analytical Model for FRP-and-Steel-Confined Circular Concrete Columns in Compression AU - Hu, Hao AU - Seracino, Rudolf T2 - Journal of Composites for Construction AB - Providing additional confinement by external fiber-reinforced polymer (FRP) wrapping is one of the most common and effective techniques for the retrofit of existing reinforced concrete columns. Over the past 2 decades, researchers have made much progress on the development of constitutive models to describe the behavior of FRP-confined circular concrete sections in compression. However, only recently have a few models been published representing the first attempts to develop a constitutive model for circular concrete columns in compression confined by both external FRP wraps and internal transverse steel. A critical review and evaluation of existing FRP-and-steel-confined concrete constitutive models highlights the need for a more robust model. This paper presents the development of a new FRP-and-steel-confined concrete in compression constitutive model for circular sections based on the passive-confinement approach. A new lateral-to-axial strain relationship and failure surface function are developed. Through a comparison with published experimental data, the accuracy of the proposed model is demonstrated. DA - 2014/6// PY - 2014/6// DO - 10.1061/(ASCE)CC.1943-5614.0000394 VL - 18 IS - 3 J2 - J. Compos. Constr. LA - en OP - SN - 1090-0268 1943-5614 UR - http://dx.doi.org/10.1061/(ASCE)CC.1943-5614.0000394 DB - Crossref KW - Concrete columns KW - Circular section KW - Confinement KW - Constitutive model KW - Fiber reinforced polymer ER - TY - JOUR TI - The Influence of Pore Solutions Properties on Drying in Cementitious Materials AU - Villani, Chiara AU - Spragg, Robert AU - Pour-Ghaz, Mohammad AU - Weiss, W. Jason T2 - JOURNAL OF THE AMERICAN CERAMIC SOCIETY AB - The drying of cementitious materials can be influenced by the properties of the fluid in the pores. While there are numerous studies on drying, very few explicitly focus on the properties of the pore fluid. This work investigates the influence of deicing salts on the properties of the pore fluid. The change that deicing salts cause in surface tension and viscosity is described in this study as a function of concentration and temperature. As a relatively limited number of measurements have been reported in literature, it can be difficult to describe the properties over a wide range of concentrations or temperatures. To overcome this limitation, this work provides measurements over concentration and temperature ranges. Semiempirical relationships were successfully fitted to the data confirming the possibility to predict viscosity and surface tension changes with temperature and salt concentration. The implications of the fluid properties on the drying behavior are also discussed as they relate to the diffusion coefficient. The models applied effectively predict the initiation of drying. Further improvements are however necessary to describe the diffusion coefficient as function of the degree of saturation in the presence of deicing salts which appear to be needed to account for the chemical interaction between the matrix and the fluid. DA - 2014/2// PY - 2014/2// DO - 10.1111/jace.12604 VL - 97 IS - 2 SP - 386-393 SN - 1551-2916 ER - TY - JOUR TI - Nanomechanical characteristics of lightweight aggregate concrete containing supplementary cementitious materials exposed to elevated temperature AU - Zadeh, V. Zanjani AU - Bobko, C. P. T2 - CONSTRUCTION AND BUILDING MATERIALS AB - In order to determine the effect of elevated temperature on hydration products of lightweight aggregate concrete containing fly ash and ground granulated blast-furnace slag, nanoindentation characteristics of three different mixtures were investigated. The results indicated existence of porosity and two types of primary hydration products, Low Density and High Density Calcium–Silicate Hydrates (LD C–S–H and HD C–S–H), in the bulk cement paste. It was revealed that there is less degradation of mechanical properties of C–S–H phases in samples of lightweight aggregate concrete exposed to elevated temperature compared to those with conventional aggregate. Additionally, the interfacial transition zone of lightweight aggregate was investigated. It was revealed that because of internal curing caused by lightweight aggregate, mechanical properties of the interfacial transition zone in these samples were very similar to bulk paste. The effect of elevated temperature, however, was more pronounced in the interfacial transition zone of lightweight aggregate than in bulk paste. A dissipated energy parameter was introduced to use in the deconvolution method which demonstrated good correlation with indentation modulus and hardness as well as packing density of the C–S–H phases in general. DA - 2014/1/31/ PY - 2014/1/31/ DO - 10.1016/j.conbuildmat.2013.10.034 VL - 51 SP - 198-206 SN - 1879-0526 KW - Elevated temperature KW - Hydration products KW - Lightweight aggregate KW - Fly ash KW - Ground granulated blast-furnace slag KW - Nanoindentation KW - Interfacial transition zone KW - Internal curing KW - Dissipated energy ER - TY - JOUR TI - Modeling the evolution of dependency between demands, with application to inventory planning AU - Norouzi, Amirhosein AU - Uzsoy, Reha T2 - IIE TRANSACTIONS AB - This article shows that the progressive realization of uncertain demands across successive discrete time periods through additive or multiplicative forecast updates results in the evolution of the conditional covariance of demand in addition to its conditional mean. A dynamic inventory model with forecast updates is used to illustrate the application of the proposed method. It is shown that the optimal inventory policy depends on conditional covariances, and a model without information updates is used to quantify the benefit of using the available forecast information in the presence of additive forecast updates. The proposed approach yields significant reductions in system costs and is applicable to a wide range of production and inventory models. It is also shown that the proposed approach can be extended to the case of multiplicative forecast updates and directions for future work are suggested. DA - 2014/1/2/ PY - 2014/1/2/ DO - 10.1080/0740817x.2013.803637 VL - 46 IS - 1 SP - 55-66 SN - 1545-8830 KW - Forecast evolution KW - conditional covariance KW - base stock policy KW - inventory planning ER - TY - JOUR TI - Factors that influence properties of FOG deposits and their formation in sewer collection systems AU - Iasmin, Mahbuba AU - Dean, Lisa O. AU - Lappi, Simon E. AU - Ducoste, Joel J. T2 - WATER RESEARCH AB - Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system. DA - 2014/2/1/ PY - 2014/2/1/ DO - 10.1016/j.watres.2013.11.012 VL - 49 SP - 92-102 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84889588357&partnerID=MN8TOARS KW - Fat, oil, and grease deposit KW - Sanitary sewer overflow (SSO) KW - Calcium based fatty acid salts ER - TY - JOUR TI - Enhanced Reductive Dechlorination of Tetrachloroethene Dense Nonaqueous Phase Liquid with EVO and Mg(OH)(2) AU - Hiortdahl, Kirsten M. AU - Borden, Robert C. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - In situ treatment of dense nonaqueous phase liquids (DNAPL) by enhanced reductive dechlorination (ERD) can be limited by contaminant toxicity, low pH, and challenges in effectively delivering electron donor. Flushing emulsified vegetable oil (EVO), colloidal Mg(OH)2 buffer, and a bioaugmentation culture (BC) through a zone containing neat tetrachloroethene (PCE) was effective in reducing contaminant toxicity, limiting pH declines, and accelerating bioenhanced dissolution of the DNAPL. In the effluent of porous media columns with little fine material, PCE concentrations reached a maximum of 40-50 times PCE aqueous solubility in water, demonstrating NAPL PCE was distributed throughout the 1.5 m column length. In a column treated with only EVO+BC, reductive dechlorination was limited. However, a single injection of EVO+Mg(OH)2+BC was effective in reducing PCE to below detection for over 400 days with a large increase in Cl(-) and dichloroethene (DCE), accelerating bioenhanced DNAPL dissolution. Dechlorination rates gradually increased over time with the rate of total ethene (TE) release from the Mg(OH)2+EVO+BC column reaching 5-6 times the TE release rate from the EVO+BC column. The accelerated dechlorination was likely due to both Mg(OH)2 addition which limited pH declines from HCl, volatile fatty acids (VFAs), and inorganic carbon (IC) production, and formation of a mixed PCE-vegetable oil NAPL which provided a readily accessible electron donor, resulting in rapid PCE degradation with reduced PCE toxicity. DA - 2014/1/7/ PY - 2014/1/7/ DO - 10.1021/es4042379 VL - 48 IS - 1 SP - 624-631 SN - 1520-5851 ER - TY - JOUR TI - Direct Displacement-Based Seismic Design of Reinforced Concrete Arch Bridges AU - Khan, Easa AU - Sullivan, Timothy J. AU - Kowalsky, Mervyn J. T2 - JOURNAL OF BRIDGE ENGINEERING AB - This paper extends the direct displacement–based design (DDBD) procedure, which was developed for buildings and conventional bridges, to the special case of RC deck arch bridges. New design expressions are formulated for the yield drift and deformation capacity of bridge piers seated on arches. The proposed methodology is applied to three case study deck arch bridges in both the longitudinal and transverse directions, and the designs are validated by nonlinear time-history analyses. The results indicate that the proposed methodology is capable of capturing the deck displacement and pier chord rotation within a reasonable degree of accuracy, although the response of the arch bridge is complex and can be affected by higher modes. The research reveals that the arch displacement may be underestimated by the DDBD procedure, but because the arch displacements are very small in comparison with the deck displacement, the DDBD procedure is still successful in controlling peak chord rotation demands on the bridge piers. DA - 2014/1/1/ PY - 2014/1/1/ DO - 10.1061/(asce)be.1943-5592.0000493 VL - 19 IS - 1 SP - 44-58 SN - 1943-5592 KW - Direct displacement-based design KW - Seismic design of deck arch bridge KW - Nonlinear time-history analyses ER - TY - JOUR TI - Approximations of the Dispersion Relationship of Water Waves AU - Yu, Jie T2 - JOURNAL OF ENGINEERING MECHANICS AB - A simple explicit formula is presented here to approximate the dispersion relationship of linear water waves, which allows direct and accurate calculation of wavenumber k for a given frequency ω. This formula is valid for all water depths, having an accuracy of the maximum error being 0.33% compared with the true solution (which is typically obtained by iterations or other root-finding numerical algorithms). It can easily be realized on a simple hand calculator (e.g., approved calculators for the Fundamentals of Engineering and the Principles and Practice of Engineering exams), and does not need any iteration, appealing in particular for practical engineering and pedagogical purposes. Another explicit formula, with still higher accuracy but slightly less simple form, is also discussed. DA - 2014/1/1/ PY - 2014/1/1/ DO - 10.1061/(asce)em.1943-7889.0000620 VL - 140 IS - 1 SP - 233-235 SN - 1943-7889 KW - Linear water waves KW - Dispersion relationship KW - Explicit formulas ER - TY - JOUR TI - Rapid assessment of foundation scour using the dynamic features of bridge superstructure AU - Elsaid, Adel AU - Seracino, Rudolf T2 - CONSTRUCTION AND BUILDING MATERIALS AB - The ability to ensure the resiliency and to predict the future performance of coastal bridges is very dependent on identifying damages in critical components of the bridge rapidly after an event. Traditional vibration based damage detection efforts focused mainly on the detection of fatigue cracking. Although detecting fatigue cracking is important, it does not contribute significantly to the total number of bridge failures in the United States. A critical review of the up-to-date literature showed that hydraulic loading, including scour, is responsible for about 50% of the failed bridges over the period of 1989–2000. To this end, the primary focus of this research is the development and evaluation of damage detection techniques capable of rapidly identifying and possibly quantifying the extent of deterioration of critical coastal bridges due to scour at submerged piers without underwater instrumentation. This paper illustrates, for the first time, the use of horizontally-displaced mode shapes and the calculated change in the dynamic flexibility features to identify scour from the response of the bridge superstructure. DA - 2014/1/15/ PY - 2014/1/15/ DO - 10.1016/j.conbuildmat.2013.08.079 VL - 50 SP - 42-49 SN - 1879-0526 KW - Structural health monitoring KW - Vibration-based damage detection KW - Scour KW - Horizontally-displaced mode shapes KW - Coastal bridges KW - Dynamic flexibility ER - TY - CONF TI - Network Level Data Collection for Asset Management of Bridge Approach Slabs AU - Gabr, Mohammed A. AU - Park, Young Jin AB - Asset management is a relatively new concept in geotechnical engineering. In general, the nature of performance data and response of structures within the realm of geotechnical engineering render the concept of asset management a valuable tool that, if effectively implemented, can lead to increased operation efficiency and cost control. Work in this paper focuses on comparing two network-level approaches for collection of data related to settlement of bridge approach slabs. These two approaches are the use of LiDAR scans and deformation profilometer. International roughness index (IRI) values and riding number (RN) values are used as output indicators of the quality of data collected in the field. Results demonstrate aspects of data collection on a network level of the bridge approach slab and summarize important features of the two approaches and data manipulation. C2 - 2014/2// C3 - Geo-Congress 2014 Technical Papers DA - 2014/2// DO - 10.1061/9780784413272.329 VL - 234 SP - 3383–3392 PB - American Society of Civil Engineers (ASCE) ER - TY - JOUR TI - Effects of Woody Vegetation on Seepage-Induced Deformation and Related Limit State Analysis of Levees AU - Khalilzad, Mahdi AU - Gabr, M. A. AU - Hynes, Mary Ellen T2 - INTERNATIONAL JOURNAL OF GEOMECHANICS AB - Work in this paper investigates the effects of woody vegetation on soil hydraulic conductivity and the related probability of exceeding deformation-based performance limit states. A summary of results obtained from laboratory and field hydraulic conductivity tests for four levee sites is presented. Limit states, as defined based on the framework of critical state soil mechanics, are developed and simple probability analyses are used to quantify the probability of exceedance under hydraulic loading. A case study of Elkhorn Levee near Sacramento, California, is presented to demonstrate the applicability of the limit states concept. The field and laboratory hydraulic conductivity data obtained from the four levee test sites show no clear trend to support the notion that woody vegetation leads to either high or low values of hydraulic conductivity; site-specific testing is needed to discern such an effect. Even though the levee case used in this study (Elkhorn) was in a marginal condition of stability, based on limit equilibrium analysis, the probability of exceeding LS III after 10 days of a sustained high water level was 2%. This probability, however, increased over time to 37 and 72% after 20 and 30 days of sustained water loading, respectively, which signifies the importance of considering the transient nature of hydraulic loading in making condition assessments after a storm event. The results of modeling a 0.75-m top root layer illustrate the impact of woody vegetation on time duration to exceed a given performance LS level and the importance of accounting for seepage-deformation responses in assessing the vulnerability of levees. DA - 2014/4/1/ PY - 2014/4/1/ DO - 10.1061/(asce)gm.1943-5622.0000304 VL - 14 IS - 2 SP - 302-312 SN - 1943-5622 KW - Vegetation KW - Roots KW - Embankment dam KW - Levee KW - Hydraulic conductivity KW - Probability of failure KW - Slope stability ER - TY - JOUR TI - An Insertion Rate Model for Pile Installation in Sand by Jetting AU - Gabr, M. A. AU - Borden, Roy H. AU - Denton, R. L. AU - Smith, Alex W. T2 - GEOTECHNICAL TESTING JOURNAL AB - The use of jetting is an approach to aid the installation of piles, especially in areas that have hard but relatively shallow subsurface soil layers. Jetting piles for a portion of their installation depth minimize their exposure to excessive driving stress and provide energy savings and noise reduction. However, the literature offers little information regarding the appropriate selection of jetting parameters, such as flow rate and jet velocity, which are needed to produce the desired installation times as a function of soil strength. This paper presents a model for estimating pile jetting parameters based on the results from laboratory and field testing. The model is based on an idealization of the applied shear stress that is produced by the jet as well as the soil resistance to pile insertion. The model is applied to 19 field installations where the jetted depths of the piles range from 10–34 ft. The field data yield ratios of 6–20 for the jet flow rate (Qw) to the rate of the pile volume insertion in terms of time (Qp), with the lower ratios associated with higher jet velocities. The proposed model yields an estimated Qw/Qp that is within +/− 20 % of the measured values. DA - 2014/1// PY - 2014/1// DO - 10.1520/gtj20120191 VL - 37 IS - 1 SP - SN - 1945-7545 KW - construction KW - criteria KW - installation KW - jetting KW - piles KW - sand KW - strength KW - stiffness ER - TY - JOUR TI - Road grade quantification based on global positioning system data obtained from real-world vehicle fuel use and emissions measurements AU - Boroujeni, Behdad Yazdani AU - Frey, H. Christopher T2 - ATMOSPHERIC ENVIRONMENT AB - Real-world vehicle fuel use and emission rates depend on engine load, which is quantified in terms of Vehicle Specific Power (VSP). VSP depends on vehicle speed, acceleration, and road grade. There is not a standard method for measuring road grade from a moving vehicle. A method for quantifying grade is evaluated based on statistical analysis of multiple runs using low cost consumer grade Global Positioning System (GPS) receivers with in-built Barometric Altimeter (GPS/BA). The average grade precision is ±0.71, ±0.46, and ±0.31 percentage points, for sample sizes of 9, 18, and 36 GPS/BA runs, respectively, among 2213 individual 0.08 km road segments. In addition, 4 sets of repeated measurements were performed on the same routes using a high cost, high accuracy Differential GPS (DGPS). Both sets of GPS-based grade estimates compared well with those derived from LIght Detection And Ranging (LIDAR) data. GPS/BA and DGPS grade estimates were similar, except for high magnitude grades of 8–10 percent for which DGPS estimates are more accurate. DGPS is more sensitive to loss of signal; thus, a hybrid approach for substituting GPS/BA data for missing DGPS data at specific locations along a route is demonstrated. The local and overall effects of road grade on fuel use and emission rates are investigated for an example light duty gasoline vehicle. DA - 2014/3// PY - 2014/3// DO - 10.1016/j.atmosenv.2013.12.025 VL - 85 SP - 179-186 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84891950017&partnerID=MN8TOARS KW - Vehicle KW - Emissions KW - Road grade KW - GPS KW - Vehicle specific power ER - TY - JOUR TI - Injury severity in delivery-motorcycle to vehicle crashes in the Seoul metropolitan area AU - Chung, Younshik AU - Song, Tai-Jin AU - Yoon, Byoung-Jo T2 - ACCIDENT ANALYSIS AND PREVENTION AB - More than 56% of motorcycles in Korea are used for the purpose of delivering parcels and food. Since such delivery requires quick service, most motorcyclists commit traffic violations while delivering, such as crossing the centerline, speeding, running a red light, and driving in the opposite direction down one-way streets. In addition, the fatality rate for motorcycle crashes is about 12% of the fatality rate for road traffic crashes, which is considered to be high, although motorcycle crashes account for only 5% of road traffic crashes in South Korea. Therefore, the objective of this study is to analyze the injury severity of vehicle-to-motorcycle crashes that have occurred during delivery. To examine the risk of different injury levels sustained under all crash types of vehicle-to-motorcycle, this study applied an ordered probit model. Based on the results, this study proposes policy implications to reduce the injury severity of vehicle-to-motorcycle crashes during delivery. DA - 2014/1// PY - 2014/1// DO - 10.1016/j.aap.2013.08.024 VL - 62 SP - 79-86 SN - 1879-2057 KW - Delivery service KW - Delivery motorcycle KW - Vehicle-to-motorcycle crash KW - Injury severity KW - Ordered probit model ER - TY - JOUR TI - How Much Do Electric Drive Vehicles Matter to Future U.S. Emissions? AU - Babaee, Samaneh AU - Nagpure, Ajay S. AU - DeCarolis, Joseph F. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Hybrid, plug-in hybrid, and battery electric vehicles—known collectively as electric drive vehicles (EDVs)—may represent a clean and affordable option to meet growing U.S. light duty vehicle (LDV) demand. The goal of this study is 2-fold: identify the conditions under which EDVs achieve high LDV market penetration in the U.S. and quantify the associated change in CO2, SO2, and NOX emissions through midcentury. We employ the Integrated MARKAL-EFOM System (TIMES), a bottom-up energy system model, along with a U.S. data set developed for this analysis. To characterize EDV deployment through 2050, varying assumptions related to crude oil and natural gas prices, a CO2 policy, a federal renewable portfolio standard, and vehicle battery cost were combined to form 108 different scenarios. Across these scenarios, oil prices and battery cost have the biggest effect on EDV deployment. The model results do not demonstrate a clear and consistent trend toward lower system-wide emissions as EDV deployment increases. In addition to the trade-off between lower tailpipe and higher electric sector emissions associated with plug-in vehicles, the scenarios produce system-wide emissions effects that often mask the effect of EDV deployment. DA - 2014/2/4/ PY - 2014/2/4/ DO - 10.1021/es4045677 VL - 48 IS - 3 SP - 1382-1390 SN - 1520-5851 ER - TY - JOUR TI - Development of system design and seismic performance evaluation for reactor pool working platform of a research reactor AU - Kwag, Shinyoung AU - Lee, Jong-Min AU - Oh, Jinho AU - Ryu, Jeong-Soo T2 - NUCLEAR ENGINEERING AND DESIGN AB - The reactor pool working platform (RPWP) has been newly designed for an open-tank-in-pool type research reactor, and its seismic response, structural integrity, serviceability, and seismic margin have been evaluated during and after seismic events in this paper. The main important concept of the RPWP is to minimize the pool top radiation level by physically covering the reactor pool of the open-tank-in-pool type research reactor and suppressing the rise of flow induced by the primary cooling system. It is also to provide easy handling of the irradiated objects under the pool water by providing guide tubes and refueling cover to make the radioisotopes irradiated and protect the reactor structure assembly. For this concept, the new three dimensional design model of the RPWP is established for manufacturing, installation and operation, and the analytical model is developed to analyze the seismic performance. Since it is submerged under and influenced by water, the hydrodynamic effect is taken into account by using the hydrodynamic added mass method. To investigate the dynamic characteristics of the RPWP, a modal analysis of the developed analytical model is performed. To evaluate the structural integrity and serviceability of the RPWP, the response spectrum analysis and response time history analysis have been performed under the static load and the seismic load of a safe shutdown earthquake (SSE). Their stresses are analyzed for the structural integrity. The possibility of an impact between the RPWP and the most adjacent structure is investigated for the serviceability. The analysis results show that the maximum stress values of the base frame, guide tubes and refueling cover of the RPWP under the seismic event are within the specified code limits. It is confirmed that an impact does not take place under a seismic event. Also, the seismic margin of the RPWP is studied, and the seismic limit to sustain the structural integrity and serviceability is attained based on the deterministic and probability methods. Lastly, the hydrodynamic effect on the seismic performance of the RPWP is quantitatively investigated and from the result, an objective basis of the consideration of the hydrodynamic influence is acquired. Therefore, it is concluded that the newly devised RPWP is safely designed in that no damage to the structural integrity and serviceability, and a sufficient seismic margin is expected. DA - 2014/1// PY - 2014/1// DO - 10.1016/j.nucengdes.2013.10.025 VL - 266 SP - 199-213 SN - 0029-5493 ER - TY - JOUR TI - Crack Density and Elastic Properties of Sustainable Concretes AU - Mccoy, B. C. AU - Leming, M. L. AU - Seracino, R. T2 - ACI Materials Journal AB - This paper examines relationships between changes in the microstructure and selected elastic properties of various concrete mixtures exposed to moderately elevated temperatures. The crack density parameters before and after exposure were estimated from the shear modulus measured wet and dry of 1 in. thick by 4 in. diameter (25 x 100 mm) disks. Mixtures examined included both granitic and lightweight coarse aggregates in combination with cementitious systems containing either 20% fly ash, 60% fly ash, termed enhanced sustainability, or 60% slag cement. This study found that the changes in crack density parameter resulting from exposure to elevated temperatures appear to be more sensitive to differences between cementitious materials than to differences between aggregate type or cementitious material proportions. A critical finding was that the relationship between initial crack density parameter and changes in crack density parameter were similar regardless of fly ash content. DA - 2014/// PY - 2014/// DO - 10.14359/51686443 VL - 111 IS - 1 SP - 13-21 ER -