TY - CONF TI - Development of probabilistic emission inventory of air toxics for jacksonville, Florida AU - Zhao, Y. AU - Christopher Frey, H. C2 - 2004/// C3 - Proceedings of the Air and Waste Management Association's Annual Meeting and Exhibition DA - 2004/// SP - 3101-3114 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-18944389363&partnerID=MN8TOARS ER - TY - BOOK TI - NOM and MIB, who wins in the competition for activated carbon adsorption sites? AU - Hepplewhite, C. AU - Newcombe, G. AU - Knappe, D.R.U. DA - 2004/// PY - 2004/// VL - 49 SE - 257-265 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3042814758&partnerID=MN8TOARS ER - TY - CHAP TI - Systematic approach for validating traffic simulation models AU - Ni, DH AU - Leonard, JD AU - Guin, A AU - Williams, BM AU - TBR T2 - Calibration and Validation of Simulation Models 2004 PY - 2004/// SP - 20-31 PB - SE - UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000227334900003&KeyUID=WOS:000227334900003 ER - TY - JOUR TI - Systematic Approach for Validating Traffic Simulation Models AU - Ni, D. AU - Leonard, J. AU - Guin, A. AU - Williams, B. T2 - Transportation Research Record AB - Modeling processes and model testing processes are discussed as parts of the model life cycle, and the tasks of these processes and their relations are highlighted. Of particular interest is the model validation process, which ensures that the model closely simulates what the real system does. A collection of validation techniques is presented to facilitate a systematic check of model performance from various perspectives. Under the qualitative category, a few graphical techniques are presented to help a visual examination of the differences between the simulation and the observation. Under the quantitative category, several statistical measures are discussed to quantify the goodness of fit; to achieve a higher level of confidence about model performance, a simultaneous statistical inference technique is proposed that tests both model accuracy and precision. As an illustrative example, these validation techniques are comprehensively applied to test an enhanced macroscopic simulation model, KWaves, in a systematic manner. DA - 2004/1/1/ PY - 2004/1/1/ DO - 10.3141/1876-03 VL - 1876 IS - 1876 SP - 20-31 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-15544373118&partnerID=MN8TOARS ER - TY - JOUR TI - Application of a viscoelastoplastic continuum damage tensile model to asphalt mixes in Sweden AU - Nilsson, B. Richard AU - Chehab, Ghassan R. AU - Kim, Y. Richard T2 - Road Materials and Pavement Design AB - ABSTRACT The objective of the research presented herein was to apply a viscoelastoplastic continuum damage (VEPCD) model on three Swedish mixes. The procedure includes the theoretical models and the supporting experimental testing protocols necessary for predicting responses of asphalt mixtures subjected to uniaxial tension loading. The model encompasses the elastic, viscoelastic, plastic and viscoplastic components of asphalt concrete behavior. Addressed are some of the major factors affecting asphalt concrete response, such as rate of loading, loading time, stress/strain amplitude, temperature, and damage. The modeling strategy is based on developing separate models for strain components and then integrating those models to form a viscoelastoplastic continuum damage (VEPCD) model. The developed model accurately predicts responses up to localization when microcracks start to coalesce and grow. However, once major macrocracks develop and propagate, the currently developed model ceases to predict responses accurately. The model was also used to evaluate and compare fatigue and rutting potential of the mixtures. DA - 2004/1// PY - 2004/1// DO - 10.1080/14680629.2004.9689991 VL - 5 IS - sup1 SP - 133-161 J2 - Road Materials and Pavement Design LA - en OP - SN - 1468-0629 2164-7402 UR - http://dx.doi.org/10.1080/14680629.2004.9689991 DB - Crossref ER - TY - JOUR TI - Determination of subgrade stiffness under intact portland cement concrete slabs for rubblization projects AU - Mun, Sungho AU - Kim, Y. Richard T2 - KSCE Journal of Civil Engineering DA - 2004/9// PY - 2004/9// DO - 10.1007/BF02899579 VL - 8 IS - 5 SP - 527-533 J2 - KSCE J Civ Eng LA - en OP - SN - 1226-7988 1976-3808 UR - http://dx.doi.org/10.1007/BF02899579 DB - Crossref ER - TY - RPRT TI - Policies for Strengthening Markets for Recyclables: A Worldwide Perspective AU - Loughlin, D.L. AU - Barlaz, M.A. A3 - Environmental Research and Education Foundation DA - 2004/// PY - 2004/// PB - Environmental Research and Education Foundation ER - TY - RPRT TI - State-of-The Practice Review of Bioreactor Landills AU - Benson, C.H. AU - Barlaz, M.A. AU - Lane, D.T. AU - Rawe, J.M. A3 - U.S. Environmental Protection Agency DA - 2004/8// PY - 2004/8// PB - U.S. Environmental Protection Agency ER - TY - RPRT TI - Critical Review of Forest Products Decomposition in Municipal Solid Waste Landfills AU - Barlaz, M.A. A3 - National Council for Air and Stream Improvement DA - 2004/// PY - 2004/// M1 - 872 M3 - Technical Bulletin PB - National Council for Air and Stream Improvement SN - 872 ER - TY - SOUND TI - Research Needs for Sustainable Solid Waste Management: A Perspective from North America AU - Barlaz, M.A. DA - 2004/// PY - 2004/// M3 - Invited lecture ER - TY - SOUND TI - The Application of Life-Cycle Analysis to Integrated Solid Waste Management Planning AU - Barlaz, M.A. DA - 2004/// PY - 2004/// M3 - Invited lecture ER - TY - SOUND TI - The Application of a Life-Cycle Analysis Decision Support Tool to Integrated Waste Management Planning in the United States AU - Barlaz, M.A. DA - 2004/// PY - 2004/// M3 - Invited lecture ER - TY - SOUND TI - Bioreactor Landfills for Refuse Decomposition AU - Barlaz, M.A. DA - 2004/// PY - 2004/// M3 - Invited lecture ER - TY - CONF TI - The Effect of Aging on the Bioavailability of Toluene Sorbed to Municipal Solid Waste Components AU - Chen, Y. AU - Knappe, D.R.U. AU - Barlaz, M.A. T2 - 3rd Intercontinental Landfill Research Symposium C2 - 2004/// CY - Lake Toya, Japan DA - 2004/// PY - 2004/11/30/ ER - TY - CONF TI - Measurement of Decomposition Rates in Landfills AU - Barlaz, M.A. T2 - 3rd Intercontinental Landfill Research Symposium C2 - 2004/// CY - Lake Toya, Japan DA - 2004/// PY - 2004/11/30/ ER - TY - CONF TI - Methanogen community structure during residential food waste decomposition in a simulated landfill AU - Staley, B.F. AU - Barlaz, M.A. AU - de los Reyes, F.L. T2 - Anaerobic Digestion 10th World Conference C2 - 2004/// CY - Montreal, CA DA - 2004/// PY - 2004/8/29/ ER - TY - CONF TI - Trace Organic Compounds in Landfill Gas Produced During the Decomposition of Refuse and Individual Waste Components AU - Barlaz, M.A. AU - Staley, B.F. AU - Cowie, S.J. AU - Hater, G.R. T2 - Anaerobic Digestion 10th World Conference C2 - 2004/// CY - Montreal, CA DA - 2004/// PY - 2004/8/29/ ER - TY - CONF TI - Production of Non-Methane Organic Compounds (NMOCs) During the Decomposition of Refuse and Individual Waste Components AU - Barlaz, M.A. AU - Staley, B.F. AU - Cowie, S.J. AU - Hater, G.R. T2 - Solid Waste Association of North America (SWANA) Landfill Symposium C2 - 2004/// CY - Monterey, CA DA - 2004/// PY - 2004/6/21/ ER - TY - CONF TI - Evaluation of a Biologically Active Cover for Mitigation of Landfill Gas Emissions AU - Barlaz, M.A. AU - Green, R AU - Chanton, J.P. AU - Goldsmith, C.D. AU - Hater, G.R. T2 - WasteTech C2 - 2004/// CY - Dallas, TX DA - 2004/// PY - 2004/5/17/ ER - TY - CONF TI - Assessing Sequential Disinfection Performance in a Flow Through System Using a Non-Biological Surrogate AU - Richards, B.H. AU - Baeza, C. AU - Ducoste, J. T2 - American Water Works Association (AWWA) Research Symposium C2 - 2004/// C3 - Proceedings, AWWA Research Symposium CY - Baltimore, Maryland DA - 2004/// PY - 2004/4/18/ ER - TY - CONF TI - Modeling Spatial Distribution of Floc size in Turbulent Processes Using Quadrature Method of Moment and Computational Fluid Dynamics AU - Prat, O. AU - Ducoste, J.J. T2 - 2nd International Conference on Population Balance Modeling C2 - 2004/// CY - Valencia, Spain DA - 2004/// PY - 2004/5/5/ ER - TY - CONF TI - Numerical Prediction of Mixing Performance for Chloramines Formation AU - Ducoste, J.J. AU - Liu, Y. T2 - American Water Works Association (AWWA) Water Quality Technology Conference C2 - 2004/// C3 - Proceedings AWWA Water Quality Technology Conference CY - San Antonio, TX DA - 2004/// PY - 2004/// ER - TY - CONF TI - Numerical Prediction of the Reduction Equivalent Fluence Bias AU - Ducoste, J.J. AU - Linden, K.G. AU - Rokjer, D. T2 - American Water Works Association (AWWA) Water Quality Technology Conference C2 - 2004/// C3 - Proceedings AWWA Water Quality Technology Conference CY - San Antonio, TX DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Performance Analysis of Quadrature Method of Moments (QMOM) for PBM Systems used in Assessing Flocculation Processes in Water and Wastewater Treatment AU - Prat, O. AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Characterizing Sequential Disinfection in Flow Through Systems AU - Richards, B. AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Characterization of Dose Distribution in UV Reactors AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Numerical Prediction of the Reduction Equivalent Fluence Bias, Invited Presentation at Degremont North AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - BOOK TI - Advances in Population Balance Modeling A3 - Nopens, I. A3 - Malise, K. A3 - Biggs, C. A3 - Ducoste, J.J. DA - 2004/// PY - 2004/// PB - Eurosis ER - TY - JOUR TI - TaN-TiN binary alloys and superlattices as diffusion barriers for copper interconnections AU - Wang, H. AU - Gupta, A. AU - Tiwari, Ashutosh AU - Zhang, X. AU - Narayan, J. T2 - Journal of Electronic Materials DA - 2004/1// PY - 2004/1// DO - 10.1007/S11664-004-0300-X VL - 33 IS - 1 SP - L5-L5 J2 - Journal of Elec Materi LA - en OP - SN - 0361-5235 1543-186X UR - http://dx.doi.org/10.1007/S11664-004-0300-X DB - Crossref ER - TY - JOUR TI - Hurricane Isabel and the NC 12 Hotspots AU - Overton, M.F. AU - Fisher, J.S. T2 - Shore and Beach DA - 2004/// PY - 2004/// VL - 72 IS - 2 SP - 30–35 ER - TY - JOUR TI - To What Extent can Climate Information Contribute to Solving Problems AU - Ward, M.N. AU - Sankarasubramanian, A. AU - Hansen, J. AU - Indeje, M. AU - Mutter, C. T2 - Clivar Exchanges DA - 2004/// PY - 2004/// VL - 9 IS - 2 SP - 5–8 ER - TY - SOUND TI - Utility of Climate Information Based Streamflow Forecasts towards Annual Water Allocation in Jaguaribe-Metropolitan Hydro (JMH) System, Ceara, NE Brazil AU - Arumugam, S. DA - 2004/3/4/ PY - 2004/3/4/ ER - TY - SOUND TI - Improved Water Allocation using Climate Information Based Streamflow Forecasts: An Assessment from System Perspective AU - Arumugam, S. DA - 2004/3/31/ PY - 2004/3/31/ ER - TY - SOUND TI - Improved Water Allocation using Climate Information Based Streamflow Forecasts: An Assessment from System Perspective AU - Arumugam, S. DA - 2004/4/29/ PY - 2004/4/29/ ER - TY - SOUND TI - Better Management through Better Decisions – Use of Climate Forecasts AU - Arumugam, S. DA - 2004/10/4/ PY - 2004/10/4/ ER - TY - CONF TI - Multimodel Probabilistic Hydroclimatic Ensemble Forecasts AU - Arumugam, S. AU - Lall, U. AU - Robertson, A.W. T2 - American Geophysical Union Spring Meeting C2 - 2004/5/17/ CY - Montreal, Quebec DA - 2004/5/17/ PY - 2004/5/17/ ER - TY - CONF TI - Operational Streamflow Forecasts Development Using GCM Predicted Precipitation Fields AU - Arumugam, S. AU - Lall, U. T2 - American Geophysical Union Fall Meeting C2 - 2004/12/12/ CY - San Francisco, CA DA - 2004/12/12/ PY - 2004/12/12/ ER - TY - JOUR TI - Cohesive sediment transport in the 3D-hydrodynamic-baroclinic circulation model, AU - Pandoe, Wahyu W. AU - Edge, Billy L. T2 - Ocean Engineering AB - This work provides a general hydrodynamic circulation model that can be used to understand density driven flows, which may arise in the case of suspension of fine-grained materials. The research is expected to provide a better understanding of the characteristics of spatial and temporal variability of current, which is associated with the period of ebb and flood tidal cycles. The model development includes extending the existing three-dimensional (3D) ADCIRC model with (1) baroclinic forcing term and (2) transport module of suspended and soluble materials. The transport module covers the erosion, material suspension and deposition processes for cohesive type sediment. In the case of an idealized tidal inlet in stratified water, the inclusion of baroclinic term can demonstrate the prevailing longshore sediment transport. It is shown that the model has application to the transport of the cohesive sediments from the mouth of the Mississippi River along the north shore of the Gulf of Mexico towards and along the Texas coast. DA - 2004/12// PY - 2004/12// DO - 10.1016/j.oceaneng.2004.04.007 VL - 31 IS - 17-18 SP - 2227-2252 J2 - Ocean Engineering LA - en OP - SN - 0029-8018 UR - http://dx.doi.org/10.1016/j.oceaneng.2004.04.007 DB - Crossref KW - three-dimensional KW - baroclinic KW - saline wedge KW - cohesive sediment transport KW - longshore transport ER - TY - JOUR TI - The influence of large-scale wind power on global climate AU - Keith, D. W. AU - DeCarolis, J. F. AU - Denkenberger, D. C. AU - Lenschow, D. H. AU - Malyshev, S. L. AU - Pacala, S. AU - Rasch, P. J. T2 - Proceedings of the National Academy of Sciences AB - Large-scale use of wind power can alter local and global climate by extracting kinetic energy and altering turbulent transport in the atmospheric boundary layer. We report climate-model simulations that address the possible climatic impacts of wind power at regional to global scales by using two general circulation models and several parameterizations of the interaction of wind turbines with the boundary layer. We find that very large amounts of wind power can produce nonnegligible climatic change at continental scales. Although large-scale effects are observed, wind power has a negligible effect on global-mean surface temperature, and it would deliver enormous global benefits by reducing emissions of CO 2 and air pollutants. Our results may enable a comparison between the climate impacts due to wind power and the reduction in climatic impacts achieved by the substitution of wind for fossil fuels. DA - 2004/11/9/ PY - 2004/11/9/ DO - 10.1073/PNAS.0406930101 VL - 101 IS - 46 SP - 16115-16120 J2 - Proceedings of the National Academy of Sciences LA - en OP - SN - 0027-8424 1091-6490 UR - http://dx.doi.org/10.1073/PNAS.0406930101 DB - Crossref ER - TY - JOUR TI - Partial interaction stresses in continuous composite beams under serviceability loads AU - Seracino, Rudolf AU - Lee, Chow T. AU - Lim, Tze C. AU - Lim, Jwo Y. T2 - Journal of Constructional Steel Research AB - The number of fatigue assessments of composite bridges is growing rapidly worldwide due to increasing allowable load limits and because many of the bridges are reaching the end of their anticipated design life. Special attention is usually given to predicting the residual endurance or strength of the shear connection because it cannot be visually inspected. However, the increased stresses in the steel and concrete components due to partial interaction must also be considered in a fatigue assessment. Based on linear elastic partial interaction theory, this paper develops a simplified procedure to predict the partial interaction curvature in continuous composite beams. When used in conjunction with focal points, the partial interaction flexural stresses in the steel and concrete components can be determined and used to more accurately predict the residual strength or endurance of the composite section. This research extends the tiered assessment approach previously published for simply supported beams so that it is now applicable to composite beams with any number of spans, span lengths, shear connection distribution and cross-section. The technique is validated using a finite element program developed to model the behaviour of composite structures and the procedure is demonstrated in an illustrative assessment. DA - 2004/10// PY - 2004/10// DO - 10.1016/j.jcsr.2004.01.002 VL - 60 IS - 10 SP - 1525-1543 J2 - Journal of Constructional Steel Research LA - en OP - SN - 0143-974X UR - http://dx.doi.org/10.1016/j.jcsr.2004.01.002 DB - Crossref KW - assessment KW - continuous composite beams KW - curvature KW - fatigue KW - flexural stresses KW - partial interaction KW - slip ER - TY - JOUR TI - Moment redistribution in continuous plated RC flexural members. Part 2: Flexural rigidity approach AU - Oehlers, D.J. AU - Liu, I.S.T. AU - Ju, G. AU - Seracino, R. T2 - Engineering Structures AB - Adhesive bonding plates to the surfaces of reinforced concrete members is now frequently used to increase both the strength and stiffness. However, because of the brittle nature of the plate debonding mechanisms, plating is often assumed to reduce the ductility to such an extent that guidelines often preclude moment redistribution. Tests on seven full-scale flexural members have shown that significant amounts of moment can be redistributed from steel and carbon fibre reinforced polymer (FRP) plated regions. In this paper, a procedure is developed for quantifying the amount of moment redistribution that can occur in externally bonded steel or FRP plated members which can be used to design plated members for ductility. DA - 2004/12// PY - 2004/12// DO - 10.1016/j.engstruct.2004.08.004 VL - 26 IS - 14 SP - 2209-2218 J2 - Engineering Structures LA - en OP - SN - 0141-0296 UR - http://dx.doi.org/10.1016/j.engstruct.2004.08.004 DB - Crossref KW - retrofitting KW - reinforced concrete beams KW - externally bonded plates KW - ductility KW - moment redistribution ER - TY - JOUR TI - Moment redistribution in continuous plated RC flexural members. Part 1: neutral axis depth approach and tests AU - Oehlers, D.J. AU - Ju, G. AU - Liu, I.S.T. AU - Seracino, R. T2 - Engineering Structures AB - It is now common practice to retrofit or rehabilitate existing reinforced concrete beams and slabs by adhesively bonding fibre reinforced polymer (FRP) or metal plates to their surfaces. Advanced design rules are available for quantifying the various plate debonding mechanisms and consequently the shear and flexural capacities of the plated sections. These design rules show that even though the required increase in strength can be obtained by plating, plate debonding can severely reduce the ductility of a flexural member to such an extent that plating guidelines often exclude moment redistribution. This exclusion may reduce the application of plating, in particular to retrofitting buildings where ductility is often a requirement, or it may require the development of a radically different approach to design that does not rely implicitly on ductility. In this paper, it is shown that the commonly used neutral axis depth approach for moment redistribution in RC flexural members cannot be used for most plated structures because plate debonding often occurs before the concrete crushes. Tests on plated flexural members are also reported which show that moment redistribution can occur. In Part 2 of this paper, a moment redistribution analysis procedure is developed that can cope with plate debonding of externally bonded plates. DA - 2004/12// PY - 2004/12// DO - 10.1016/j.engstruct.2004.08.003 VL - 26 IS - 14 SP - 2197-2207 J2 - Engineering Structures LA - en OP - SN - 0141-0296 UR - http://dx.doi.org/10.1016/j.engstruct.2004.08.003 DB - Crossref KW - retrofitting KW - reinforced concrete beams KW - externally bonded plants KW - ductility KW - moment redistribution ER - TY - JOUR TI - Full-range behavior of FRP-to-concrete bonded joints AU - Yuan, H. AU - Teng, J.G. AU - Seracino, R. AU - Wu, Z.S. AU - Yao, J. T2 - Engineering Structures AB - External bonding of fiber reinforced polymer (FRP) composites has become a popular technique for strengthening concrete structures all over the world. The performance of the interface between FRP and concrete is one of the key factors affecting the behavior of the strengthened structure, and has been widely studied using simple shear tests on FRP plate/sheet-to-concrete bonded joints. While a great deal of research is now available on the behavior of these bonded joints, no closed-form analytical solution has been presented which is capable of predicting the entire debonding propagation process. This paper presents such an analytical solution, in which the realistic bi-linear local bond–slip law is employed. Expressions for the interfacial shear stress distribution and load–displacement response are derived for different loading stages. It is also shown how experimental load–displacement responses of these joints can be used to quantify interfacial properties, including the interfacial fracture energy and parameters of the local bond–slip relationship. The debonding process is discussed in detail and the analytical results are compared with experimental data. Finally, results from the analytical solution are presented to illustrate how the bond length and the plate stiffness affect the behavior of such bonded joints. While the emphasis of the paper is on FRP-to-concrete joints, the analytical solution is equally applicable to similar joints between thin plates of other materials (e.g. steel and aluminum) and concrete. DA - 2004/4// PY - 2004/4// DO - 10.1016/j.engstruct.2003.11.006 VL - 26 IS - 5 SP - 553-565 J2 - Engineering Structures LA - en OP - SN - 0141-0296 UR - http://dx.doi.org/10.1016/j.engstruct.2003.11.006 DB - Crossref KW - FRP KW - concrete KW - bond KW - interface KW - bond behavior KW - bond strength KW - effective bond length KW - bond-slip model KW - debonding KW - interfacial fracture energy KW - interfacial parameters KW - analytical solution ER - TY - JOUR TI - Kinetics of soil ozonation: an experimental and numerical investigation AU - Shin, Won-Tae AU - Garanzuay, Xandra AU - Yiacoumi, Sotira AU - Tsouris, Costas AU - Gu, Baohua AU - Mahinthakumar, G.(Kumar) T2 - Journal of Contaminant Hydrology AB - This study investigates the use of ozone for soil remediation. Batch experiments, in which ozone-containing gas was continuously recycled through a soil bed, were conducted to quantify the rate of ozone self-decomposition and the rates of ozone interaction with soil organic and inorganic matter. Column experiments were conducted to measure ozone breakthrough from a soil column. Parameters such as ozone flow rate, soil mass, and ozonation time were varied in these experiments. After ozone concentration had reached steady state, the total organic carbon concentration was measured for all soil samples. The ozonation efficiency, represented by the ratio of soil organic matter consumed to the total ozone input, was quantified for each experiment. Numerical simulations were conducted to simulate experimentally obtained column breakthrough curves. Experimentally obtained kinetic rate constants were used in these simulations, and the results were in good agreement with experimental data. In contrast to previous studies in which soil inorganic matter was completely ignored, our experiments indicate that soil inorganic matter may also promote depletion of ozone, thus reducing the overall ozonation efficiency. Three-dimensional numerical simulations were conducted to predict the efficacy of ozonation for soil remediation in the field. These simulations indicate that such ozonation can be very effective, provided that effective circulation of ozone is achieved through appropriately placed wells. DA - 2004/8// PY - 2004/8// DO - 10.1016/j.jconhyd.2003.11.003 VL - 72 IS - 1-4 SP - 227-243 J2 - Journal of Contaminant Hydrology LA - en OP - SN - 0169-7722 UR - http://dx.doi.org/10.1016/j.jconhyd.2003.11.003 DB - Crossref KW - ozone KW - chemical oxidation KW - soil remediation KW - numerical modeling KW - soil organic matter ozonation ER - TY - JOUR TI - Using neural network to predict performance of design-build projects in Singapore AU - Ling, Florence Yean Yng AU - Liu, Min T2 - Building and Environment AB - Design-build (DB) project success may be operationalised into 11 performance metrics. 65 factors that may affect DB project success are identified. Using data from 33 DB projects, correlation analysis shows that there are several factors that affect each performance metric significantly. Artificial neural network (ANN) technique is used to construct the models to predict project performance, and these models are tested using data from five new projects. This study finds that six performance metrics can be predicted with a reasonable degree of accuracy: project intensity; construction and delivery speeds; turnover, system and equipment quality. The key variables that affect project performance may be attributed to both contractors and clients. To ensure project success, contractors should have adequate staffing level, a good track record for completion on budget, and ability in financial management and quality control. Consultants should have a high level of construction sophistication, and have handled DB projects in the past. Clients also play an important part in ensuring DB project success. They would need to have construction experience and handled DB projects in the past. In addition, they should decide on the optimal level of design completion when the budget is fixed and tenders are invited. It is recommended that owners and contractors take note of the factors identified in this study, which significantly affect DB project performance. DA - 2004/10// PY - 2004/10// DO - 10.1016/j.buildenv.2004.02.008 VL - 39 IS - 10 SP - 1263-1274 J2 - Building and Environment LA - en OP - SN - 0360-1323 UR - http://dx.doi.org/10.1016/j.buildenv.2004.02.008 DB - Crossref KW - artificial neural network KW - project performance KW - critical success factors KW - key determinants KW - design-build ER - TY - CONF TI - Generating Urban Watershed Management Alternatives Using Evolutionary Algorithms AU - Dorn, J. L. AU - Ranjithan, S. T2 - World Water and Environmental Resources Congress 2004 AB - The design of urban drainage networks is complicated by the need to consider a number of issues that conflict and compete with the goal of managing flood impacts. These issues primarily include environmental considerations, but may also include issues such as developable land impacts, system reliability, wetland impacts, aesthetics, etc., some of which may not be modeled explicitly. Modeling to generate alternatives (MGA) is a formal optimization-based technique to find near optimal alternatives that are maximally different from one another with respect to their decision attributes. This paper presents a new evolutionary algorithm (EA)-based technique, the Solution Set Algorithm (SSA), for performing MGA and its application to design problem involving the design a least-cost drainage network using the EPA's Storm Water Management Model (SWMM). C2 - 2004/6/25/ C3 - Critical Transitions in Water and Environmental Resources Management DA - 2004/6/25/ DO - 10.1061/40737(2004)241 PB - American Society of Civil Engineers SN - 9780784407370 UR - http://dx.doi.org/10.1061/40737(2004)241 DB - Crossref ER - TY - JOUR TI - A Procedure for Life-Cycle-Based Solid Waste Management with Consideration of Uncertainty AU - Kaplan, P. Özge AU - Barlaz, Morton A. AU - Ranjithan, S. Ranji T2 - Journal of Industrial Ecology AB - The development of integrated solid‐waste management (SWM) strategies that are efficient with respect to both cost and environmental performance is a complex task. It must incorporate the numerous interrelations among different unit operations in the solid waste system (e.g., collection, recycling, and combustion), and the large number of design parameters that affect estimates of cost and environmental emissions. Uncertainty in design and operational parameters can lead to uncertainty in the estimates of cost and emissions. This article describes an extension of the capability of the Integrated Solid Waste Management Decision Support Tool (ISWM DST) to enable consideration of the effects of uncertainty in input parameters. The uncertainty analysis capability is illustrated using a hypothetical case study of a typical municipality. Results show that increased expenditure does not necessarily result in a reduction in the expected levels of environmental emissions and that some SWM alternatives may be more robust, although deterministic estimates of their expected performances are similar. The uncertainty analysis also facilitates use of the ISWM DST by policy makers responsible for evaluation of the expected effect of SWM practices on, for example, greenhouse‐gas emissions. DA - 2004/9// PY - 2004/9// DO - 10.1162/1088198043630531 VL - 8 IS - 4 SP - 155-172 J2 - Journal of Industrial Ecology LA - en OP - SN - 1088-1980 UR - http://dx.doi.org/10.1162/1088198043630531 DB - Crossref ER - TY - CONF TI - Lessons for applying computational fluid dynamics modeling to disinfection clearwells AU - Peplinski, D.K. AU - Ducoste, J.J. AB - Computational Fluid Dynamics (CFD) modeling offers the potential of improving disinfection contactor hydraulics, allowing a decrease in the applied disinfectant dose without a decrease in the level of microbial inactivation. For treatment systems utilizing chlorine as a disinfectant, this would result in both a reduction in chemical costs and in disinfection by-products (DBPs). Current modeling of clearwell hydraulics is based on accurate prediction of the effluent residence time distribution (RTD) curve. Researchers have shown that CFD models can predict a majority of the experimental RTD curve, but under certain circumstances may not reproduce the entire curve. The objectives of this study were to numerically characterize tracer transport through a disinfection contactor, investigate the impact of grid density, time step interval, and investigate the impact of accurately modeling perforated baffles on the resulting RTD curve. C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)22 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649146660&partnerID=MN8TOARS ER - TY - CONF TI - Development of probabilistic emission inventory of air toxics for Jacksonville, Florida AU - Zhao, Y. AU - Frey, H.C. C2 - 2004/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2004/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21944442584&partnerID=MN8TOARS ER - TY - CONF TI - Assessment of uncertainty in benzene concentration estimates in the Houston, TX, area AU - Hanna, A.F. AU - Vukovich, J.M. AU - Arunachalam, S. AU - Loughlin, D. AU - Frey, H.C. AU - Isakov, V. C2 - 2004/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2004/// SP - 3129-3143 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21944435254&partnerID=MN8TOARS ER - TY - CONF TI - A Monte Carlo study of the uncertainties in predictions by ISC3ST and AERMOD of annual average benzene and 1,3-butadiene concentrations around the Houston Ship Channel AU - Hanna, S.R. AU - Heinold, D. AU - Paine, R. AU - Frey, H.C. AU - Baker, D. AU - Karp, R. AU - Feldman, H. C2 - 2004/// C3 - Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA DA - 2004/// SP - 3145-3157 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-21944432040&partnerID=MN8TOARS ER - TY - CONF TI - System-wide optimization of wastewater treatment plants using genetic algorithms C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)106 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649101286&partnerID=MN8TOARS ER - TY - CHAP TI - Assessment of ADCIRC's wetting and drying algorithm AU - Dietrich, JC AU - Kolar, RL AU - Luettich, RA AU - Miller, CT AU - Farthing, MW AU - Gray, WG AU - Pinder, GF T2 - Computational Methods in Water Resources, Vols 1 and 2 PY - 2004/// VL - 55 SP - 1767-1778 PB - SE - UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000228987900150&KeyUID=WOS:000228987900150 ER - TY - JOUR TI - A 2D implicit time-marching algorithm for shallow water models based on the generalized wave continuity equation AU - Dresback, Kendra M. AU - Kolar, Randall L. AU - Dietrich, J. Casey T2 - International Journal for Numerical Methods in Fluids AB - Abstract This paper builds upon earlier work that developed and evaluated a 1D predictor–corrector time‐marching algorithm for wave equation models and extends it to 2D. Typically, the generalized wave continuity equation (GWCE) utilizes a three time‐level semi‐implicit scheme centred at k, and the momentum equation uses a two time‐level scheme centred at k+12. It has been shown that in highly non‐linear applications, the algorithm becomes unstable at even moderate Courant numbers. This work implements and analyses an implicit treatment of the non‐linear terms through the use of an iterative time‐marching algorithm in the two‐dimensional framework. Stability results show at least an eight‐fold increase in the maximum time step, depending on the domain. Studies also examined the sensitivity of the G parameter (a numerical weighting parameter in the GWCE) with results showing the greatest increase in stability occurs when 1⩽G/τ max ⩽10, a range that coincides with the recommended range to minimize errors. Convergence studies indicate an increase in temporal accuracy from first order to second order, while overall error is less than the original algorithm, even at higher time steps. Finally, a parallel implementation of the new algorithm shows that it scales well. Copyright © 2004 John Wiley & Sons, Ltd. DA - 2004/4/23/ PY - 2004/4/23/ DO - 10.1002/fld.697 VL - 45 IS - 3 SP - 253-274 J2 - Int. J. Numer. Meth. Fluids LA - en OP - SN - 0271-2091 1097-0363 UR - http://dx.doi.org/10.1002/fld.697 DB - Crossref KW - shallow water equations KW - finite elements KW - generalized wave continuity equation KW - implicit time-marching KW - parallel computing ER - TY - JOUR TI - Relationship of species-specific filament levels to filamentous bulking in activated sludge. AU - Liao, J. AU - Lou, I. AU - Reyes, F. L. T2 - Appl Environ Microbiol DA - 2004/// PY - 2004/// VL - 70 IS - 4 SP - 2420-8 ER - TY - JOUR TI - Relationship of species-specific filament levels to filamentous bulking in activated sludge AU - Liao, JY AU - Lou, IC AU - Reyes, FL T2 - Applied and Environmental Microbiology AB - ABSTRACT To examine the relationship between activated-sludge bulking and levels of specific filamentous bacteria, we developed a statistics-based quantification method for estimating the biomass levels of specific filaments using 16S rRNA-targeted fluorescent in situ hybridization (FISH) probes. The results of quantitative FISH for the filament Sphaerotilus natans were similar to the results of quantitative membrane hybridization in a sample from a full-scale wastewater treatment plant. Laboratory-scale reactors were operated under different flow conditions to develop bulking and nonbulking sludge and were bioaugmented with S. natans cells to stimulate bulking. Instead of S. natans , the filament Eikelboom type 1851 became dominant in the reactors. Levels of type 1851 filaments extending out of the flocs correlated strongly with the sludge volume index, and extended filament lengths of approximately 6 × 10 8 μm ml −1 resulted in bulking in laboratory-scale and full-scale activated-sludge samples. Quantitative FISH showed that high levels of filaments occurred inside the flocs in nonbulking sludge, supporting the “substrate diffusion limitation” hypothesis for bulking. The approach will allow the monitoring of incremental improvements in bulking control methods and the delineation of the operational conditions that lead to bulking due to specific filaments. DA - 2004/// PY - 2004/// DO - 10.1128/AEM.70.4.2420-2428.2004 VL - 70 IS - 4 SP - 2420-2428 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000220792200064&KeyUID=WOS:000220792200064 ER - TY - JOUR TI - OPTIMIZATION OF INTERMITTENT AERATION FOR NITROGEN REMOVAL FROM SWINE WASTEWATER AU - Ridenoure, Jennifer A. AU - Head, Melanie A. AU - Mota, Cesar R. AU - Reyes, Francis L. AU - Cheng, Jay J. T2 - proc water environ fed DA - 2004/1/1/ PY - 2004/1/1/ DO - 10.2175/193864704784131671 VL - 2004 IS - 10 SP - 238-245 ER - TY - JOUR TI - HEAT TREATMENT COMBINED WITH CATION ADDITION TO IMPROVE THE DEWATERABILITY OF WASTE ACTIVATED SLUDGE AU - Skidmore, Matthew AU - Reyes, Francis T2 - proc water environ fed DA - 2004/1/1/ PY - 2004/1/1/ DO - 10.2175/193864704784136847 VL - 2004 IS - 8 SP - 48-57 ER - TY - JOUR TI - EFFECTS OF AERATION CYCLES ON POPULATIONS OF NITRIFYING BACTERIA AND NITROGEN REMOVAL IN INTERMITTENTLY-AERATED REACTORS AU - Mota, Cesar R. AU - Ridenoure, Jennifer AU - Head, Melanie AU - Cheng, Jiayang AU - Reyes, Francis L. T2 - proc water environ fed AB - EFFECTS OF AERATION CYCLES ON POPULATIONS OF NITRIFYING BACTERIA AND NITROGEN REMOVAL IN INTERMITTENTLY-AERATED REACTORSBiological nutrient removal relies on different groups of nitrifying bacteria, which convert ammonia to nitrate or nitrite, and denitrifying bacteria, which convert nitrite or nitrate to nitrogen gas. The key to efficient, robust biological nitrogen removal processes relies on knowing the microorganisms involved and how they respond to different operating conditions. Intermittently aerated...Author(s)Cesar R. MotaJennifer RidenoureMelanie HeadJiayang ChengFrancis L. de los ReyesSourceProceedings of the Water Environment FederationSubjectSession 39: Activated Sludge—Filaments, Foaming, Toxics and MoreDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2004ISSN1938-6478SICI1938-6478(20040101)2004:13L.776;1-DOI10.2175/193864704784138016Volume / Issue2004 / 13Content sourceWEFTECFirst / last page(s)776 - 789Copyright2004Word count164 DA - 2004/1/1/ PY - 2004/1/1/ DO - 10.2175/193864704784138016 VL - 2004 IS - 13 SP - 776-789 ER - TY - JOUR TI - DETERMINING GROWTH RATE, YIELD AND MAINTENANCE COEFFICIENT OF FILAMENTS AND FLOC FORMERS USING SUBSTRATE UPTAKE TESTS AND METABOLIC MODELING AU - Lou, Inchio AU - Reyes, Francis L. T2 - proc water environ fed DA - 2004/1/1/ PY - 2004/1/1/ DO - 10.2175/193864704784137701 VL - 2004 IS - 13 SP - 690-700 ER - TY - CONF TI - An Interface Data Model for HEC-HMS AU - Obenour, Daniel AU - Maidment, David AU - Evans, Thomas AU - Yates, Daniel C2 - 2004/// C3 - Proc. AWRA 2004 Annual Conference DA - 2004/// ER - TY - CONF TI - Vitri: A framework for environmental decision support on heterogeneous computer networks AB - Vitri is an object-oriented framework implemented in Java for high-performance distributed computing. Using Vitri, applications can engage in cooperative problem solving by dividing their tasks among heterogeneous clusters of workstations and PCs. Vitri's features include basic support for distributed computing and communication, as well as visual tools for evaluating run-time performance, and modules for heuristic optimization. It balances loads dynamically using a client-side task pool, allows the addition or removal of servers dating a run, and provides fault tolerance transparently for servers and networks. Among its more powerful features are modules for heuristic optimization, including an asynchronous global-parallel genetic algorithm that is particularly suited for coarse-grained tasks executing on processors with large variations in processor speeds. By using dataflow techniques, in which computations are explicitly based on the availability and forwarding of data, the usual end-of-generation synchronization points are removed from the algorithm. Results are presented for illustrative applications in water distribution network design and air quality management. C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)111 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649149870&partnerID=MN8TOARS ER - TY - CONF TI - Method for least cost design of looped pipe networks for different levels of redundancy using genetic algorithms AU - Kumar, S.V. AU - Doby, T.A. AU - Baugh, J.W. AU - Brill, E.D. AU - Ranjithan, S.R. AB - A new method is proposed for the least cost design of looped piped networks under various levels of redundancy using a genetic algorithm. Various levels of redundancy can be obtained by considering the number of pipes to be taken out of service at any one time. As a result, a tradeoff curve of redundancy and cost can be developed. The approach is being extended to consider different measures of redundancy as well as other performance criteria. Such extensions are more computationally demanding and are therefore being implemented using a distributed GA. C2 - 2004/// C3 - Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000: Building Partnerships DA - 2004/// DO - 10.1061/40517(2000)201 VL - 104 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-74949091879&partnerID=MN8TOARS ER - TY - CONF TI - Genetic algorithm search for least cost design of looped pipe networks using age as a quality surrogate and different levels of redundancy AU - Doby, T.A. AU - Kumar, S.V. AU - Baugh, J.W. AU - Brill, E.D. AU - Ranjithan, S.R. AB - A genetic algorithm- (GA-) based method is being investigated for determining the least cost design of looped networks while considering the residence time of the water in the network as a quality surrogate and various levels of redundancy. The conflict among the three design objectives, i.e., cost, redundancy, and water quality, is examined via multiobjective analysis. C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)387 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649129137&partnerID=MN8TOARS ER - TY - CONF TI - Alternatives in the implementation of internet-enabled laboratory experiments in undergraduate civil engineering courses AU - Gupta, A. AU - Gabr, M. A. AU - Matzen, V. C. C2 - 2004/// C3 - ASEE 2004 annual conference & exposition$h[electronic resource] :June 20-23, 2004, Salt Lake City, Utah : Engineering education reaches new heights : conference proceedings DA - 2004/// PB - Washington, D.C.: American Soceity for Engineering Education ER - TY - JOUR TI - A linear referencing system for NCDOT AU - Kiel, D. AU - Rasdorf W., Shuller AU - E., AU - Poole, R. T2 - Computer-Aided Civil and Infrastructure Engineering DA - 2004/// PY - 2004/// VL - 19 IS - 3 SP - 170-185 ER - TY - RPRT TI - Business process analysis of the city of Raleigh public utilities water warehouse AU - Rasdorf, W. A3 - Raleigh, N.C.: North Carolina State University DA - 2004/// PY - 2004/// PB - Raleigh, N.C.: North Carolina State University ER - TY - RPRT TI - An overview of the business operations process for road inventory data AU - Cox, H. AU - Rasdorf, W. A3 - Raleigh, N.C.: North Carolina Department of Transportation DA - 2004/// PY - 2004/// PB - Raleigh, N.C.: North Carolina Department of Transportation ER - TY - CONF TI - Optimization of intermittent aeration for nitrogen removal from swine wastewater AU - Ridenoure, J. A. AU - Head, M. A. AU - Mota, C. R. AU - Reyes F. L., AU - Cheng, J. C2 - 2004/// C3 - 77th Annual Technical Exhibition and Conference : the water quality event : Ernest N. Morial Convention Center, New Orleans, Louisiana, USA, October 2-6, 2004 DA - 2004/// ER - TY - CONF TI - Effects of aeration cycles on populations of nitrifying bacteria and nitrogen removal in intermittently-aerated reactors AU - Mota, C. R. AU - Ridenoure, J. A. AU - Cheng, J. AU - Reyes F. L., C2 - 2004/// C3 - 77th Annual Technical Exhibition and Conference : the water quality event : Ernest N. Morial Convention Center, New Orleans, Louisiana, USA, October 2-6, 2004 DA - 2004/// ER - TY - JOUR TI - The effects of infrared loading and water table on soil energy fluxes in northern peatlands AU - Noormets, A AU - Chen, JQ AU - Bridgham, SD AU - Weltzin, JF AU - Pastor, J AU - Dewey, B AU - LeMoine, J T2 - ECOSYSTEMS DA - 2004/8// PY - 2004/8// DO - 10.1007/s10021-004-0013-2 VL - 7 IS - 5 SP - 573-582 SN - 1435-0629 KW - heat flux KW - infrared loading KW - mesocosm KW - net radiation KW - soil energy balance KW - wetland ER - TY - JOUR TI - A working framework for quantifying carbon sequestration in disturbed land mosaics AU - Chen, Jiquan AU - Brosofske, Kimberley D. AU - Noormets, Asko AU - Crow, Thomas R. AU - Bresee, Mary K. AU - Le Moine, James M. AU - Euskirchen, Eugenie S. AU - Mather, Steve V. AU - Zheng, Daolan T2 - ENVIRONMENTAL MANAGEMENT DA - 2004/7// PY - 2004/7// DO - 10.1007/s00267-003-9131-4 VL - 33 SP - S210-S221 SN - 0364-152X KW - carbon flux KW - land mosaics KW - management and disturbance KW - eddy-covariance method KW - ecosystem modeling KW - soil respiration ER - TY - DATA TI - EC_Processor AU - Noormets, A. AU - Zhou, R. AU - Chen, J. DA - 2004/// PY - 2004/// ER - TY - JOUR TI - Evaluation of uncertainties associated with geocoding techniques AU - Karimi, HA AU - Durcik, M AU - Rasdorf, W T2 - COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING AB - Abstract: Spatial databases contain geocoded data. Geocoded data play a major role in numerous engineering applications such as transportation and environmental studies where geospatial information systems (GIS) are used for spatial modeling and analysis as they contain spatial information (e.g., latitude and longitude) about objects. The information that a GIS produces is impacted by the quality of the geocoded data (e.g., coordinates) stored in its database. To make appropriate and reasonable decisions using geocoded data, it is important to understand the sources of uncertainty in geocoding. There are two major sources of uncertainty in geocoding, one related to the database that is used as a reference data set to geocode objects and one related to the interpolation technique used. Factors such as completeness, correctness, consistency, currency, and accuracy of the data in the reference database contribute to the uncertainty of the former whereas the specific logic and assumptions used in an interpolation technique contribute to the latter. The primary purpose of this article is to understand uncertainties associated with interpolation techniques used for geocoding. In doing so, three geocoding algorithms were used and tested and the results were compared with the data collected by the Global Positioning System (GPS). The result of the overall comparison indicated no significant differences between the three algorithms . DA - 2004/5// PY - 2004/5// DO - 10.1111/j.1467-8667.2004.00346.x VL - 19 IS - 3 SP - 170-185 SN - 1093-9687 ER - TY - JOUR TI - Alternative approaches for state agencies to address the proposed minimum retroreflectivity standards AU - Vereen, S. AU - Hummer, J. AU - Rasdorf, W. T2 - Public Works Management & Policy AB - This work aimed to determine, quantify, and present alternative approaches for agencies to meet the Federal Highway Administration's (FHWA) proposed minimum levels of retroreflectivity for signs. This study based these approaches on current North Carolina Department of Transportation sign maintenance practices and sought to minimize the cost and labor required to meet FHWA standards. This article offers four approaches: Nighttime visual inspection (current method), improved nighttime visual inspection procedures, sign inventory management system (no visual inspection), and combination of alternatives #2 and #3. This study ultimately recommends alternative #4, although it is the most costly. This article also recommends that an evaluation be made periodically to determine what benefits and improvement in sign condition, if any, have resulted from implementation. DA - 2004/// PY - 2004/// DO - 10.1177/1087724x04263208 VL - 8 IS - 4 SP - 235-248 ER - TY - CONF TI - Empowering learning in engineering: a study of learning styles, strategies, and success of first-year students AU - Anson, C. M. AU - Bernold, L. E. AU - Spurlin, J. AU - Crossland, C. C2 - 2004/// C3 - International Conference on Engineering Education and Research DA - 2004/// M1 - June ER - TY - CONF TI - Interface behavior of granular soils AU - Frost, J. D. AU - Hebeler, G. L. AU - Evans, T. M. AU - DeJong, J. T. A2 - R. B. Malla, A2 - Maji, A. AB - Interface shear zones between particulate materials and continuum elements of man-made or natural materials have not been traditionally considered as shear bands. However, the results of recent micro-scale experimentation and numerical simulations have shown that they are indeed well developed partial shear bands. Further, these studies have indicated that significant similarities can be identified between these partial shear bands and what are more traditionally considered to be shear bands that evolve wholly within particulate materials. This paper presents results from physical and numerical experiments that suggest there is significant merit to this opinion. The physical experiments include quantitative analysis of the particle deformation following shear adjacent to continuum surfaces of different roughness as well as analyses of sand specimens sheared to different global strain levels. Complimentary 2-D Discrete Element Method modeling of particulate-continuum surface interfaces illustrates this parallel behavior. C2 - 2004/// C3 - Engineering, construction, and operations in challenging environments : Earth and Space 2004 : proceedings of the Ninth biennial ASCE Aerospace Division International Conference on Engineering, Construction, and Operations in Challenging Environments, March 7-10, 2004, League City, Houston, Texas DA - 2004/// DO - 10.1061/40722(153)10 SP - 65-72 PB - Reston, VA: American Society of Civil Engineers SN - 0784407223 ER - TY - JOUR TI - Influence of confinement on the cyclic behavior of reinforced clay brick masonry walls AU - Durham, A. S. AU - Kowalsky, M. J. T2 - Masonry Society Journal DA - 2004/// PY - 2004/// VL - 22 IS - 1 ER - TY - JOUR TI - Compressive behavior of unconfined and confined clay brick masonry AU - Ewing, B. D. AU - Kowalsky, M. J. T2 - Journal of Structural Engineering (New York, N.Y.) AB - Presented in this paper are the results of an investigation of the compressive behavior of grouted clay brick masonry prisms. The objective is to experimentally capture the stress–strain characteristics of unconfined and confined clay brick masonry and compare the response with that predicted with the “modified” Kent–Park stress–strain curve. Based on the experimental results, five limit states for clay brick masonry in compression are proposed, as well as equivalent stress blocks for design. Thin galvanized steel plates placed in the mortar joints during construction provided prism confinement. The variables considered included volumetric ratio of confining steel (0, ∼0.015, and ∼0.03) and the presence of machined holes within the confinement plates to improve the bond between the masonry and steel plate. It is shown that confinement plates are extremely effective in enhancing the ultimate compressive strength as well as increasing the deformation capacity of the clay brick masonry prisms. The use of confinement plates in the test increased the ultimate compression strength by 40%. Failure of the confined masonry prisms occurred simultaneously or immediately after yielding of the confinement plates. Experimentally obtained stress–strain curves agreed reasonably well with the modified Kent–Park model. DA - 2004/// PY - 2004/// DO - 10.1061/(asce)0733-9445(2004)130:4(650) VL - 130 IS - 4 SP - 650-661 ER - TY - JOUR TI - Fatigue cracking mechanisms in asphalt pavements with viscoelastic continuum damage finite-element program AU - Mun, S AU - Guddati, MN AU - Kim, YR T2 - PAVEMENT DESIGN AND ACCELERATED TESTING 2004 AB - A study of fatigue-cracking mechanisms in asphalt pavements used the finite-element program VECD-FEP++. This program employs the viscoelastic continuum damage model for the asphalt layer and a nonlinear elastic model for unbound layers. Both bottom-up and top-down cracks are investigated by taking several important variables, such as asphalt layer thickness, layer stiffness, pressure distribution under loading, and load level applied on the pavement surface, into account. The cracking mechanisms in various pavement structures under different loading conditions are studied by monitoring a damage contour. Preferred conditions for top-down cracking were identified with the results from this parametric study. The conjoined damage contours in thicker pavements suggest that a through-the-thickness crack may develop as the bottom-up and top-down cracks propagate simultaneously and coalesce; that idea supports observations from field cores and raises the question of the validity of traditional fatigue performance models that account for the growth of the bottom-up cracking only. DA - 2004/// PY - 2004/// DO - 10.3141/1896-10 IS - 1896 SP - 96-106 SN - 0361-1981 ER - TY - JOUR TI - Engineering properties of historic brick: Variability considerations as a function of stationary versus nonstationary kiln types AU - Laefer, DF AU - Boggs, J AU - Cooper, N T2 - JOURNAL OF THE AMERICAN INSTITUTE FOR CONSERVATION DA - 2004/// PY - 2004/// DO - 10.2307/4129639 VL - 43 IS - 3 SP - 255-272 SN - 0197-1360 ER - TY - CHAP TI - Methodology for prioritizing and expanding freeway service patrols AU - Khattak, A. AU - Rouphail, N. AU - Monast, K. AU - Havel, J. T2 - Calibration and validation of simulation models 2004 CN - TE7 .H5 no. 1876 PY - 2004/// SP - 1-10 PB - Washington, DC: Transportation Research Board SN - 0309094704 ER - TY - JOUR TI - Strengthening steel structures and bridges with high-modulus carbon fiber-reinforced polymers - Resin selection and scaled monopole behavior AU - Schnerch, D AU - Stanford, K AU - Sumner, EA AU - Rizkalla, S T2 - DESIGN OF STRUCTURES 2004 AB - Cost-effective solutions for the rehabilitation and strengthening of steel structures, including bridges and monopole towers, are greatly needed. Rehabilitation is often required because of cross-section losses occurring as a result of corrosion; strengthening may also be required because of changes in the use of a structure. Current techniques for strengthening steel structures have several drawbacks, including their fatigue performance and the need for ongoing maintenance owing to continued corrosion attack. The current research program makes use of a high-modulus carbon fiber for the strengthening of steel structures. This program, currently in progress, includes phases for the resin and adhesive selection for wet layup of carbon fiber sheets and bonding of precured laminate plates. Test results of the first scaled monopole tower showed a 25% increase in stiffness in the elastic range compared with the same monopole before strengthening. DA - 2004/// PY - 2004/// DO - 10.3141/1892-25 IS - 1892 SP - 237-245 SN - 0361-1981 ER - TY - CHAP TI - Relationship between elastic modulus and permeability of damaged concrete AU - Dilek, U. AU - Leming, M. L. AU - Guth, D. T2 - Concrete, 2004 AB - The study examined the effects of selected damage mechanisms on the dynamic elastic (Young's) modulus (E d ) and air permeability index (API) of concrete. The relationship between E d and API in damaged concrete and the use of E d and API to determine both the extent of damage due to various exposures and the presence and extent of damage gradients are reviewed. The E d and API were determined by using 25-mm-thick disks sawed from high-strength and conventional- strength concrete cylinders, before and after static fatigue damage; from cores removed from a lightweight, precast, prestressed concrete beam after exposure to intense fire; and from cores removed from an elevated concrete slab after exposure to thermal shock and subsequent cryogenic temperatures. The findings of the study suggested that E d and API were linearly related for a given set of raw materials until damage was significant, that analyzing concrete disks at 25-mm (1-in.) depths provided insight into damage gradients, and that the durability of high-strength concrete in service may have been better than conventional-strength concrete under similar stress conditions. E d and API were found to be effective tools in the assessment of damaged concrete and gradients of damage. API was found to be particularly sensitive to fire damage and associated severe drying. CN - TE7 .H5 NO.1893 PY - 2004/// DO - 10.3141/1893-07 SP - 53-60 PB - Washington, DC: Transportation Research Board SN - 0309094909 ER - TY - CHAP TI - Predicting tunneling-induced ground movement AU - Laefer, D. F. AU - Kim, W. S. T2 - Design of structures, 2004 CN - TE7 .H5 NO.1892 PY - 2004/// SP - 208-217 PB - Washington, DC: Transportation Research Board SN - 0309094879 ER - TY - CHAP TI - Fatigue behavior of prestressed tubular bridge deck of fiber-reinforced polymer AU - Wu, Z. H. AU - Mirmiran, A. AU - Swanson, J. T2 - Design of structures, 2004 CN - TE7 .H5 NO.1892 PY - 2004/// SP - 246-255 PB - Washington, DC: Transportation Research Board SN - 0309094879 ER - TY - JOUR TI - Dynamic modulus testing of asphalt concrete in indirect tension mode AU - Kim, YR AU - Seo, Y AU - King, M AU - Momen, M T2 - BITUMINOUS PAVING MIXTURES 2004 AB - This study presents the results from an analytical and experimental study on the dynamic modulus testing of hot-mix asphalt using the indirect tension (IDT) mode. An analytical solution for the dynamic modulus in the IDT mode was developed with the use of linear viscoelasticity. To verify the analytical solution, temperature and frequency sweep tests were conducted on 12 asphalt mixtures commonly used in North Carolina; both axial compression and IDT test methods were used. A modified dynamic modulus test protocol is introduced to reduce the required testing time by using more frequencies and fewer temperatures on the basis of the time-temperature superposition principle. A comparison of results from the axial compression and IDT test methods shows that the dynamic modulus master curves and shift factors derived from the two methods are in good agreement. It also was found that Poisson's ratio was a weak function of the loading frequency; its effect on the phase angle master curve is discussed. DA - 2004/// PY - 2004/// DO - 10.3141/1891-19 IS - 1891 SP - 163-173 SN - 0361-1981 ER - TY - JOUR TI - Stay-in-place fiber reinforced polymer forms for precast modular bridge pier system AU - Zhu, Z. Y. AU - Mirmiran, A. AU - Shahawy, M. T2 - Journal of Composites for Construction AB - This paper presents an innovative modular construction of bridge pier system with stay-in-place fiber reinforced polymer (FRP) forms filled with concrete. Two 1/6 scale precast modular frames were prepared of a prototype bridge pier system. Three different types of connections were considered: male-female, dowel reinforced with or without tube embedment, and posttensioned. The frames were load tested in negative and positive bending. Subsequently, the cap beams were cut from the frames and tested to failure in four-point bending. Posttensioned joints exhibited the most robust and ductile behavior and proved to be the preferred method of joining stay-in-place forms. Even with dowel bars, the male-female joints lacked the necessary structural integrity in the pier frames. Better surface preparation for FRP units and higher quality grouting may improve the response. Embedment of the columns into the footing provided additional stiffness for the connection. The study indicated that internal reinforcement is not necessary for the stay-in-place forms outside the connection zone. The experiments also showed the importance of maintaining appropriate tolerances and match casting for male-female and embedment connections. Overall, however, feasibility of the precast modular FRP system was demonstrated in this study. DA - 2004/// PY - 2004/// DO - 10.1061/(ASCE)1090-0268(2004)8:6(560) VL - 8 IS - 6 SP - 560-568 ER - TY - JOUR TI - Development of probabilistic emission inventories of air toxics for Jacksonville, Florida AU - Zhao, YC AU - Frey, HC T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Probabilistic emission inventories were developed for 1,3-butadiene, mercury (Hg), arsenic (As), benzene, formaldehyde, and lead for Jacksonville, FL. To quantify inter-unit variability in empirical emission factor data, the Maximum Likelihood Estimation (MLE) method or the Method of Matching Moments was used to fit parametric distributions. For data sets that contain nondetected measurements, a method based upon MLE was used for parameter estimation. To quantify the uncertainty in urban air toxic emission factors, parametric bootstrap simulation and empirical bootstrap simulation were applied to uncensored and censored data, respectively. The probabilistic emission inventories were developed based on the product of the uncertainties in the emission factors and in the activity factors. The uncertainties in the urban air toxics emission inventories range from as small as -25 to +30% for Hg to as large as -83 to +243% for As. The key sources of uncertainty in the emission inventory for each toxic are identified based upon sensitivity analysis. Typically, uncertainty in the inventory of a given pollutant can be attributed primarily to a small number of source categories. Priorities for improving the inventories and for refining the probabilistic analysis are discussed. DA - 2004/11// PY - 2004/11// DO - 10.1080/10473289.2004.10471002 VL - 54 IS - 11 SP - 1405-1421 SN - 2162-2906 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8444251311&partnerID=MN8TOARS ER - TY - JOUR TI - Quantification of variability and uncertainty for air toxic emission inventories with censored emission factor data AU - Frey, HC AU - Zhao, YC T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Probabilistic emission inventories were developed for urban air toxic emissions of benzene, formaldehyde, chromium, and arsenic for the example of Houston. Variability and uncertainty in emission factors were quantified for 71−97% of total emissions, depending upon the pollutant and data availability. Parametric distributions for interunit variability were fit using maximum likelihood estimation (MLE), and uncertainty in mean emission factors was estimated using parametric bootstrap simulation. For data sets containing one or more nondetected values, empirical bootstrap simulation was used to randomly sample detection limits for nondetected values and observations for sample values, and parametric distributions for variability were fit using MLE estimators for censored data. The goodness-of-fit for censored data was evaluated by comparison of cumulative distributions of bootstrap confidence intervals and empirical data. The emission inventory 95% uncertainty ranges are as small as −25% to +42% for chromium to as large as −75% to +224% for arsenic with correlated surrogates. Uncertainty was dominated by only a few source categories. Recommendations are made for future improvements to the analysis. DA - 2004/11/15/ PY - 2004/11/15/ DO - 10.1021/es035096m VL - 38 IS - 22 SP - 6094-6100 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-8544262958&partnerID=MN8TOARS ER - TY - JOUR TI - Methodology for pH Total Maximum Daily Loads: Application to Beech Creek Watershed AU - Ormsbee, Lindell AU - Elshorbagy, Amin AU - Zechman, Emily T2 - Journal of Environmental Engineering AB - This paper presents a methodology for developing total maximum daily loads (TMDLs) for pH impaired streams that characterizes the pH impact in terms of an associated hydrogen ion load. Because pH and an equivalent ion load can be related as a function of discharge and ionic strength, a functional relationship can be developed between discharge and the associated ion loading for a given pH value. By specifying a minimum pH value (e.g., 6.0) and an associated ion activity correction factor, an envelope of ion loads may be obtained as a function of discharge. By identifying a critical discharge for a given watershed, the hydrogen ion load and associated TMDL can be obtained. Determination of the associated ion load reduction can further be accomplished by developing functional relationships between measured discharges and measured ion loads for a given watershed. Finally, the required mass loading of an associated neutralizing agent (e.g., CaCO3) can be determined by constructing a functional relationship between the neutralizing agent and the required hydrogen ion reduction. The proposed approach has been applied to several watersheds in the state of Kentucky and was recently approved by EPA Region IV as an acceptable protocol for pH TMDLs. An application of the methodology is presented for the Beech Creek watershed, which is located in Muhlenberg County, Kentucky. DA - 2004/2// PY - 2004/2// DO - 10.1061/(asce)0733-9372(2004)130:2(167) VL - 130 IS - 2 SP - 167-174 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(asce)0733-9372(2004)130:2(167) DB - Crossref ER - TY - CHAP TI - Estimating link delays for arterial streets AU - Torres, E. AU - Nelson, P. AU - Rouphail, N. AU - Raj, J. T2 - Urban and regional transportation modeling, essays in honor of David Boyce CN - HE305 .U683 2004 PY - 2004/// PB - Northhampton, MA: Edward Elgar SN - 1843763060 ER - TY - JOUR TI - Quantification of variability and uncertainty for censored data sets and application to air toxic emission factors AU - Zhao, YC AU - Frey, HC T2 - RISK ANALYSIS AB - Many environmental data sets, such as for air toxic emission factors, contain several values reported only as below detection limit. Such data sets are referred to as "censored." Typical approaches to dealing with the censored data sets include replacing censored values with arbitrary values of zero, one-half of the detection limit, or the detection limit. Here, an approach to quantification of the variability and uncertainty of censored data sets is demonstrated. Empirical bootstrap simulation is used to simulate censored bootstrap samples from the original data. Maximum likelihood estimation (MLE) is used to fit parametric probability distributions to each bootstrap sample, thereby specifying alternative estimates of the unknown population distribution of the censored data sets. Sampling distributions for uncertainty in statistics such as the mean, median, and percentile are calculated. The robustness of the method was tested by application to different degrees of censoring, sample sizes, coefficients of variation, and numbers of detection limits. Lognormal, gamma, and Weibull distributions were evaluated. The reliability of using this method to estimate the mean is evaluated by averaging the best estimated means of 20 cases for small sample size of 20. The confidence intervals for distribution percentiles estimated with bootstrap/MLE method compared favorably to results obtained with the nonparametric Kaplan-Meier method. The bootstrap/MLE method is illustrated via an application to an empirical air toxic emission factor data set. DA - 2004/8// PY - 2004/8// DO - 10.1111/j.0272-4332.2004.00504.x VL - 24 IS - 4 SP - 1019-1034 SN - 1539-6924 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544222855&partnerID=MN8TOARS KW - Bootstrap simulation KW - censored data sets KW - Kaplan-Meier estimator KW - maximum likelihood estimation KW - Monte Carlo simulation KW - nondetects KW - urban air toxics ER - TY - JOUR TI - Near-surface-mounted fiber-reinforced polymer reinforcements for flexural strengthening of concrete structures AU - El-Hacha, R. AU - Rizkalla, S. H. T2 - ACI Structural Journal AB - First Name is required invalid characters Last Name is required invalid characters Email Address is required Invalid Email Address Please select a country... Afghanistan Åland Islands Albania Algeria American Samoa Andorra Angola Anguilla Antarctica Antigua And Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Antarctic Territory British Indian Ocean Territory British Overseas Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cabo Verde Cambodia Cameroon Canada Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, Democratic Republic of the Cook Islands Costa Rica Côte d'Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guam Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City) Honduras Hong Kong Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea (the Republic of) Korea, Democratic People's Republic of Kosovo, Republic of Kuwait Kyrgyzstan Lao People's Democratic Republic Latvia Lebanon Lesotho Liberia Libya Liechtenstein Lithuania Luxembourg Macau Macedonia, Former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Marshall Islands Martinique Mauritania Mauritius Mayotte Mexico Micronesia, Federated States of Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Northern Mariana Islands Norway Oman Pakistan Palau Palestine, State of Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Puerto Rico Qatar Réunion Romania Russian Federation Rwanda Saint Barthélemy Saint Kitts And Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Samoa San Marino Sao Tome And Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia South Sudan Spain Sri Lanka St Vincent And Grenadines St. Helena Ascensian and Tristan da Aunh Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad And Tobago Tunisia Turkey Turkmenistan Turks And Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States United States Minor Outlying Islands Uruguay Uzbekistan Vanuatu Venezuela Viet Nam Virgin Islands (British) Virgin Islands (U.S.) Wallis And Futuna Islands Western Sahara Yemen Zambia Zimbabwe Country/Territory is required DA - 2004/// PY - 2004/// DO - 10.14359/13394 VL - 101 IS - 5 SP - 717-726 ER - TY - JOUR TI - Evaluation of a biologically active cover for mitigation of landfill gas emissions AU - Barlaz, MA AU - Green, RB AU - Chanton, JP AU - Goldsmith, CD AU - Hater, GR T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Landfills are the third largest source of anthropogenic CH4 in the United States, and there is potential for reduction in this source of greenhouse gases and other contaminants. The objective of this work was to contrast emissions of CH4 and non-methane organic compounds (NMOCs) from landfill cells covered with soil or a biologically active cover consisting of yard waste compost. On the basis of four field campaigns over 14 months, CH4 emissions from the biocover (BC) varied from −1.73 to 1.33 g m-2 d-1, with atmospheric uptake measured in 52% of tests. BC emissions did not increase when the gas collection system was turned off. Uptake of atmospheric CH4 was measured in 54% of tests on the soil cover (SC) when the gas collection was system active and 12% when the gas collection system was off. Many (26%) relatively high fluxes (>15 g m-2 d-1) were measured from the SC as were some dramatic effects due to deactivation of the gas collection system. In tests with positive emissions, stable isotope measurements showed that the BC and SC were responsible for oxidation of 55% and 21% of the CH4 reaching the bottom of the respective cover. Seven of the highest 10 NMOC emissions were measured in the SC, and 17 of 21 fluxes for speciated organic compounds were higher in the SC. The relationship between CH4, NMOC, and individual organic compound emissions suggested a correlation between CH4 and trace organic oxidation. BCs can reduce landfill gas emissions in the absence of a gas collection system and can serve as a polishing step in the presence of an active system. DA - 2004/9/15/ PY - 2004/9/15/ DO - 10.1021/es049605b VL - 38 IS - 18 SP - 4891-4899 SN - 1520-5851 ER - TY - JOUR TI - Corrigendum to "Decolorizing of lignin wastewater using the photochemical UV/TiO2 process" (vol 56, pg 1011, 2004) AU - Chang, CN AU - Ma, YS AU - Fang, GC AU - Chao, AC AU - Tsai, MC AU - Sung, HF T2 - CHEMOSPHERE DA - 2004/11// PY - 2004/11// DO - 10.1016/j.chemosphere.2004.08.002 VL - 57 IS - 6 SP - 529-529 SN - 0045-6535 ER - TY - BOOK TI - Algae detection and removal strategies for drinking water treatment plants AU - Knappe, D. R. U. CN - TD465 .A43 2004 DA - 2004/// PY - 2004/// PB - Denver Colo.: AWWA Research Foundation and American Water Works Association SN - 1583213074 ER - TY - JOUR TI - Optimization under variability and uncertainty: A case study for NOx emissions control for a gasification system AU - Chen, JJ AU - Frey, HC T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Methods for optimization of process technologies considering the distinction between variability and uncertainty are developed and applied to case studies of NOx control for Integrated Gasification Combined Cycle systems. Existing methods of stochastic optimization (SO) and stochastic programming (SP) are demonstrated. A comparison of SO and SP results provides the value of collecting additional information to reduce uncertainty. For example, an expected annual benefit of 240,000 dollars is estimated if uncertainty can be reduced before a final design is chosen. SO and SP are typically applied to uncertainty. However, when applied to variability, the benefit of dynamic process control is obtained. For example, an annual savings of 1 million dollars could be achieved if the system is adjusted to changes in process conditions. When variability and uncertainty are treated distinctively, a coupled stochastic optimization and programming method and a two-dimensional stochastic programming method are demonstrated via a case study. For the case study, the mean annual benefit of dynamic process control is estimated to be 700,000 dollars, with a 95% confidence range of 500,000 dollars to 940,000 dollars. These methods are expected to be of greatest utility for problems involving a large commitment of resources, for which small differences in designs can produce large cost savings. DA - 2004/12/15/ PY - 2004/12/15/ DO - 10.1021/es0351037 VL - 38 IS - 24 SP - 6741-6747 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-10644257613&partnerID=MN8TOARS ER - TY - JOUR TI - Modified integration rules for reducing dispersion error in finite element methods AU - Guddati, MN AU - Yue, B T2 - COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING AB - This paper describes a simple but effective technique for reducing dispersion errors in finite element solutions of time-harmonic wave propagation problems. The method involves a simple shift of the integration points to locations away from conventional Gauss or Gauss–Lobatto integration points. For bilinear rectangular elements, such a shift results in fourth-order accuracy with respect to dispersion error (error in wavelength), as opposed to the second-order accuracy resulting from conventional integration. Numerical experiments involving distorted meshes indicate that the method has superior performance in comparison with other dispersion reducing finite elements. DA - 2004/// PY - 2004/// DO - 10.1016/j.cma.2003.09.010 VL - 193 IS - 3-5 SP - 275-287 SN - 1879-2138 KW - wave propagation KW - numerical dispersion KW - numerical integration KW - Helmholtz equation ER - TY - JOUR TI - Kinetics of soil ozonation: an experimental and numerical investigation AU - Shin, W. T. AU - Garanzuay, X. AU - Yiacoumi, S. AU - Tsouris, C. AU - Gu, B. H. AU - Mahinthakumar, G. K. T2 - Journal of Contaminant Hydrology AB - This study investigates the use of ozone for soil remediation. Batch experiments, in which ozone-containing gas was continuously recycled through a soil bed, were conducted to quantify the rate of ozone self-decomposition and the rates of ozone interaction with soil organic and inorganic matter. Column experiments were conducted to measure ozone breakthrough from a soil column. Parameters such as ozone flow rate, soil mass, and ozonation time were varied in these experiments. After ozone concentration had reached steady state, the total organic carbon concentration was measured for all soil samples. The ozonation efficiency, represented by the ratio of soil organic matter consumed to the total ozone input, was quantified for each experiment. Numerical simulations were conducted to simulate experimentally obtained column breakthrough curves. Experimentally obtained kinetic rate constants were used in these simulations, and the results were in good agreement with experimental data. In contrast to previous studies in which soil inorganic matter was completely ignored, our experiments indicate that soil inorganic matter may also promote depletion of ozone, thus reducing the overall ozonation efficiency. Three-dimensional numerical simulations were conducted to predict the efficacy of ozonation for soil remediation in the field. These simulations indicate that such ozonation can be very effective, provided that effective circulation of ozone is achieved through appropriately placed wells. DA - 2004/// PY - 2004/// DO - 10.1016/j.conhyd.2003.11.003 VL - 72 IS - 04-Jan SP - 227-243 ER - TY - JOUR TI - Issues affecting measurement of the complex modulus of asphalt concrete AU - Daniel, J. S. AU - Chehab, G. R. AU - Kim, Y. R. T2 - Journal of Materials in Civil Engineering AB - This paper addresses issues of machine compliance and instrumentation that affect the measurement of asphalt concrete material properties in the laboratory. Accurate determination of fundamental material properties is becoming increasingly important as the asphalt industry moves toward more mechanistic design procedures. This issue is particularly timely for the simple performance test and American Association of State Highway and Transportation Officials 2002 design guide that require the measurement of dynamic modulus, phase angle, and creep. The primary objective of this paper is to increase the awareness of the possible existence of these issues in the laboratory and the importance of attending to them appropriately. Machine compliance was found to affect the strains actually occurring in the specimen under various loading conditions, resulting in differences of several magnitudes between dynamic modulus values measured by the actuator and by surface-mounted deformation transducers. Instrumentation issues resulted in errors greater than 10% in the measurement of dynamic modulus for the mixtures studied and caused irrational trends in phase angle values as a function of frequency. Creep compliance testing was also found to be affected by instrumentation issues. DA - 2004/// PY - 2004/// DO - 10.1061/(ASCE)0899-1561(2004)16:5(469) VL - 16 IS - 5 SP - 469-476 ER - TY - JOUR TI - Effect of cellulose/hemicellulose and lignin on the bioavailability of toluene sorbed to waste paper AU - Chen, Y AU - Knappe, DRU AU - Barlaz, NA T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Paper constitutes about 38% of municipal solid waste, much of which is disposed of in landfills. Sorption to such lignocellulosic materials may limit the bioavailability of organic contaminants in landfills. The objective of this study was to identify the effect of individual biopolymers in paper on toluene sorption and bioavailability by subjecting fresh and anaerobically degraded office paper and newsprint to enzymatic hydrolysis and acid hydrolysis. Enzymatic degradation of cellulose and hemicellulose had no effect on toluene bioavailability. In contrast, acid-insoluble lignin controlled toluene sorption and bioavailability for both fresh and degraded newsprint. Acid-insoluble lignin could explain only 54% of the toluene sorption capacity of degraded office paper however, suggesting that crude protein and/or lipophilic organic matter were also important sorbent phases. Toluene sorbed to degraded office paper was also less bioavailable than toluene sorbed to an equivalent mass of lignin extracted from this sorbent. The latter result suggests that a fraction of toluene sorbed to degraded office paper may have been sequestered by lipophilic organic matter. The sorption and bioavailability data indicate that the preferential decomposition of cellulose and hemicellulose relative to lignin in landfills should not decrease the overall toluene sorption capacity of paper waste or increase the bioavailability of sorbed toluene. DA - 2004/7/1/ PY - 2004/7/1/ DO - 10.1021/es035286x VL - 38 IS - 13 SP - 3731-3736 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3042787671&partnerID=MN8TOARS ER - TY - JOUR TI - Design for torsion and shear in prestressed concrete flexural members AU - Zia, P AU - Hsu, TTC T2 - PCI JOURNAL AB - This paper presents a unified method for the torsion and shear design of prestressed and non-prestressed concrete flexural members, and provides an alternative method to the provisions of the ACI Building Code. The method applies to rectangular, box and flanged sections such as L-beams. The approach depends on subdividing the given section into component rectangles. Equations are given for the shear and torsion web reinforcement of beams as well as expressions for the minimum reinforcement and required amount of longitudinal steel. The design method is illustrated with a fully worked numerical example of a spandrel beam. The shear and torsion provisions in the Sixth Edition of the PCI Design Handbook are based on the principles outlined in this paper, which will also be referenced in ACI 318-05. The design method has been shown to be reliable, accurate and easy to use. DA - 2004/// PY - 2004/// DO - 10.15554/pcij.05012004.34.42 VL - 49 IS - 3 SP - 34-+ SN - 0887-9672 KW - beams KW - design (structural) KW - L-beams KW - prestressed concrete KW - spandrel beams KW - reinforced concrete KW - reinforcement KW - shear strength KW - spandrel beams KW - torsion strength KW - web reinforcement ER - TY - JOUR TI - Continuous precipitation polymerization of vinylidene fluoride in supercritical carbon dioxide: modeling the molecular weight distribution AU - Ahmed, T. S. AU - Desimone, J. M. AU - Roberts, G. W. T2 - Chemical Engineering Science DA - 2004/// PY - 2004/// VL - 59 IS - 22-23 SP - 5139-5144 ER - TY - JOUR TI - Chemical characterization and sorption capacity measurements of degraded newsprint from a landfill AU - Chen, LX AU - Nanny, MA AU - Knappe, DRU AU - Wagner, TB AU - Ratasuk, N T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Newsprint samples collected from 12−16 ft (top layer (TNP)), 20−24 ft (middle layer (MNP)), and 32−36 ft (bottom layer (BNP)) below the surface of the Norman Landfill (NLF) were characterized by infrared (IR) spectroscopy, cross-polarization, magic-angle spinning 13C nuclear magnetic resonance (CP-MAS 13C NMR) spectroscopy, and tetramethylammonium hydroxide (TMAH) thermochemolysis gas chromatography/mass spectrometry (GC/MS). The extent of NLF newsprint degradation was evaluated by comparing the chemical composition of NLF newsprint to that of fresh newsprint (FNP) and newsprint degraded in the laboratory under methanogenic conditions (DNP). The O-alkyl/alkyl, cellulose/lignin, and lignin/resin acid ratios showed that BNP was the most degraded, and that all three NLF newsprint samples were more degraded than DNP. 13C NMR and TMAH thermochemolysis data demonstrated selective enrichment of lignin over cellulose, and TMAH thermochemolysis further exhibited selective enrichment of resin acids over lignin. In addition, the crystallinity of cellulose in NLF newsprint samples was significantly lower relative to that of FNP and DNP as shown by 13C NMR spectra. The yield of lignin monomers from TMAH thermochemolysis suggested that hydroxyl groups were removed from the propyl side chain of lignin during the anaerobic decomposition of newsprint in the NLF. Moreover, the vanillyl acid/aldehyde ratio, which successfully describes aerobic lignin degradation, was not a good indicator of the anaerobic degradation of lignin on the basis of the TMAH data. The toluene sorption capacity increased as the degree of newsprint degradation increased or as the O-alkyl/alkyl ratio of newsprint decreased. The results of this study further verified that the sorbent O-alkyl/alkyl ratio is useful for predicting sorption capacities of natural organic materials for hydrophobic organic contaminants. DA - 2004/7/1/ PY - 2004/7/1/ DO - 10.1021/es0305914 VL - 38 IS - 13 SP - 3542-3550 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3042751476&partnerID=MN8TOARS ER - TY - JOUR TI - Bond mechanism of near-surface-mounted fiber-reinforced polymer bars for flexural strengthening of concrete structures AU - Hassan, T. K. AU - Rizkalla, S. H. T2 - ACI Structural Journal AB - First Name is required invalid characters Last Name is required invalid characters Email Address is required Invalid Email Address Invalid Email Address DA - 2004/// PY - 2004/// DO - 10.14359/13458 VL - 101 IS - 6 SP - 830-839 ER - TY - JOUR TI - An evolutionary algorithm to generate alternatives (EAGA) for engineering optimization problems AU - Zechman, Emily M. AU - Ranjithan, S. Ranji T2 - Engineering Optimization AB - Typically for a real optimization problem, the optimal solution to a mathematical model of that real problem may not always be the ‘best’ solution when considering unmodeled or unquantified objectives during decision-making. Formal approaches to explore efficiently for good but maximally different alternative solutions have been established in the operations research literature, and have been shown to be valuable in identifying solutions that perform expectedly well with respect to modeled and unmodeled objectives. While the use of evolutionary algorithms (EAs) to solve real engineering optimization problems is becoming increasingly common, systematic alternatives-generation capabilities are not fully extended for EAs. This paper presents a new EA-based approach to generate alternatives (EAGA), and illustrates its applicability via two test problems. A realistic airline route network design problem was also solved and analyzed successfully using EAGA. The EAGA promises to be a flexible procedure for exploring alternative solutions that could assist when making decisions for real engineering optimization problems riddled with unmodeled or unquantified issues. DA - 2004/10// PY - 2004/10// DO - 10.1080/03052150410001704863 VL - 36 IS - 5 SP - 539-553 J2 - Engineering Optimization LA - en OP - SN - 0305-215X 1029-0273 UR - http://dx.doi.org/10.1080/03052150410001704863 DB - Crossref KW - genetic algorithm KW - evolutionary algorithm KW - modeling to generate alternatives KW - niching ER - TY - JOUR TI - A new type of water-soluble fluorescent boronic acid suitable for construction of polyboronic acids for carbohydrate recognition AU - Yang, W. Q. AU - Li, L. AU - Wang, B. H. T2 - Heterocyclic Communications DA - 2004/// PY - 2004/// VL - 10 IS - 6 SP - 383-388 ER - TY - JOUR TI - Quantification of variability and uncertainty using mixture distributions: Evaluation of sample size, mixing weights, and separation between components AU - Zheng, JY AU - Frey, HC T2 - RISK ANALYSIS AB - Variability is the heterogeneity of values within a population. Uncertainty refers to lack of knowledge regarding the true value of a quantity. Mixture distributions have the potential to improve the goodness of fit to data sets not adequately described by a single parametric distribution. Uncertainty due to random sampling error in statistics of interests can be estimated based upon bootstrap simulation. In order to evaluate the robustness of using mixture distribution as a basis for estimating both variability and uncertainty, 108 synthetic data sets generated from selected population mixture log-normal distributions were investigated, and properties of variability and uncertainty estimates were evaluated with respect to variation in sample size, mixing weight, and separation between components of mixtures. Furthermore, mixture distributions were compared with single-component distributions. Findings include: (1). mixing weight influences the stability of variability and uncertainty estimates; (2). bootstrap simulation results tend to be more stable for larger sample sizes; (3). when two components are well separated, the stability of bootstrap simulation is improved; however, a larger degree of uncertainty arises regarding the percentiles coinciding with the separated region; (4). when two components are not well separated, a single distribution may often be a better choice because it has fewer parameters and better numerical stability; and (5). dependencies exist in sampling distributions of parameters of mixtures and are influenced by the amount of separation between the components. An emission factor case study based upon NO(x) emissions from coal-fired tangential boilers is used to illustrate the application of the approach. DA - 2004/6// PY - 2004/6// DO - 10.1111/j.0272-4332.2004.00459.x VL - 24 IS - 3 SP - 553-571 SN - 1539-6924 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3042716474&partnerID=MN8TOARS KW - bootstrap simulation KW - mixture distributions KW - parameter estimation KW - uncertainty KW - variability ER - TY - JOUR TI - Natural treatment and onsite processes AU - Liehr, SK AU - Rubin, AR AU - Tonning, B T2 - WATER ENVIRONMENT RESEARCH AB - Water Environment ResearchVolume 76, Issue 6 p. 1191-1237 Treatment SystemFree Access Natural Treatment and Onsite Processes Sarah K. Liehr, Sarah K. LiehrSearch for more papers by this authorA. Robert Rubin, A. Robert RubinSearch for more papers by this authorBarry Tonning, Barry TonningSearch for more papers by this author Sarah K. Liehr, Sarah K. LiehrSearch for more papers by this authorA. Robert Rubin, A. Robert RubinSearch for more papers by this authorBarry Tonning, Barry TonningSearch for more papers by this author First published: 01 October 2004 https://doi.org/10.2175/106143004X142059Citations: 11AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume76, Issue62004 Literature ReviewSeptember-October 2004Pages 1191-1237 RelatedInformation DA - 2004/// PY - 2004/// DO - 10.2175/106143004X142059 VL - 76 IS - 6 SP - 1191-1237 SN - 1061-4303 ER - TY - JOUR TI - NOM and MIB, who wins in the competition for activated carbon adsorption sites? AU - Hepplewhite, C AU - Newcombe, G AU - Knappe, DRU T2 - WATER SCIENCE AND TECHNOLOGY AB - The adsorption of an odour compound common in drinking water, 2-methylisoborneol (MIB), was studied on two activated carbons in the presence of 13 well-characterised natural organic matter (NOM) solutions. It was found that, although the carbons and the NOM solutions had a wide range of characteristics, the major competitive mechanism was the same in all cases. The low molecular weight NOM compounds were the most competitive, participating in a direct competition with the MIB molecule for adsorption sites. Equivalent background concentration (EBC) calculations indicated a relatively low concentration of directly competing compounds in the NOM. Some evidence of pore restriction was also seen, with microporous carbons most affected by low molecular weight NOM, and mesoporous carbons impacted by the higher molecular weight compounds. DA - 2004/// PY - 2004/// DO - 10.2166/wst.2004.0584 VL - 49 IS - 9 SP - 257-265 SN - 1996-9732 KW - activated carbon KW - adsorption KW - adsorption competition KW - MIB KW - natural organic material KW - tastes and odours ER - TY - JOUR TI - Intraparticle diffusion and adsorption of arsenate onto granular ferric hydroxide (GFH) AU - Badruzzaman, M AU - Westerhoff, P AU - Knappe, DRU T2 - WATER RESEARCH AB - Porous iron oxides are being evaluated and selected for arsenic removal in potable water systems. Granular ferric hydroxide, a typical porous iron adsorbent, is commercially available and frequently considered in evaluation of arsenic removal methods. GFH is a highly porous (micropore volume ∼0.0394±0.0056 cm3 g−1, mesopore volume ∼0.0995±0.0096 cm3 g−1) adsorbent with a BET surface area of 235±8 m2 g−1. The purpose of this paper is to quantify arsenate adsorption kinetics on GFH and to determine if intraparticle diffusion is a rate-limiting step for arsenic removal in packed-bed treatment systems. Data from bottle-point isotherm and differential column batch reactor (DCBR) experiments were used to estimate Freundlich isotherm parameters (K and 1/n) as well as kinetic parameters describing mass transfer resistances due to film diffusion (kf) and intraparticle surface diffusion (Ds). The pseudo-equilibrium (18 days of contact time) arsenate adsorption density at pH 7 was 8 μg As/mg dry GFH at a liquid phase arsenate concentration of 10 μg As/L. The homogeneous surface diffusion model (HSDM) was used to describe the DCBR data. A non-linear relationship (DS=3.0−9×Rp1.4) was observed between Ds and GFH particle radius (RP) with Ds values ranging from 2.98×10−12 cm2 s−1 for the smallest GFH mesh size (100×140) to 64×10−11 cm2 s−1 for the largest GFH mesh size (10×30). The rate-limiting process of intraparticle surface diffusion for arsenate adsorption by porous iron oxides appears analogous to organic compound adsorption by activated carbon despite differences in adsorption mechanisms (inner-sphere complexes for As versus hydrophobic interactions for organic contaminants). The findings are discussed in the context of intraparticle surface diffusion affecting packed-bed treatment system design and application of rapid small-scale column tests (RSSCTs) to simulate the performance of pilot- or full-scale systems at the bench-scale. DA - 2004/11// PY - 2004/11// DO - 10.1016/j.watres.2004.07.007 VL - 38 IS - 18 SP - 4002-4012 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-4544343747&partnerID=MN8TOARS KW - arsenic KW - iron KW - adsorption KW - surface diffusion KW - water treatment ER - TY - JOUR TI - Evaluation of alternative fluence rate distribution models AU - Liu, D AU - Ducoste, J AU - Jin, S AU - Linden, K T2 - JOURNAL OF WATER SUPPLY RESEARCH AND TECHNOLOGY-AQUA AB - Research Article| September 01 2004 Evaluation of alternative fluence rate distribution models Dong Liu; Dong Liu 1Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 208 Mann Hall CB 7908, Raleigh, NC 27695-7908, USA Search for other works by this author on: This Site PubMed Google Scholar Joel Ducoste; Joel Ducoste 1Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 208 Mann Hall CB 7908, Raleigh, NC 27695-7908, USA E-mail: jducoste@eos.ncsu.edu Search for other works by this author on: This Site PubMed Google Scholar Shanshan Jin; Shanshan Jin 2Degremont North American Research & Development Center, 510 E. Jackson St, Richmond, VA 23219, USA Search for other works by this author on: This Site PubMed Google Scholar Karl Linden Karl Linden 3Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2004) 53 (6): 391–408. https://doi.org/10.2166/aqua.2004.0031 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Dong Liu, Joel Ducoste, Shanshan Jin, Karl Linden; Evaluation of alternative fluence rate distribution models. Journal of Water Supply: Research and Technology-Aqua 1 September 2004; 53 (6): 391–408. doi: https://doi.org/10.2166/aqua.2004.0031 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex A detailed evaluation of several fluence rate distribution models was performed. These models included line source integration (LSI), multiple points source summation (MPSS), multiple segment source summation (MSSS), UVCalc3D, RAD-LSI, view factor and discrete ordinate (DO). As part of the evaluation, a complete MSSS model, which accounts for the quartz sleeve thickness when calculating the refraction angles, was developed. In addition, a simple attenuation factor was introduced to integrate the physics of reflection, refraction and absorption effects into the LSI model. As an alternative simple correction to the LSI, the RAD-LSI incorporates the RADIAL intensity model into the original LSI formulation. All models were compared with experimental measurements using spherical actinometers, which measure the fluence rate at specific points in space. Experimental measurements were performed in air and water. Experiments in water were performed at two different ultraviolet transmittance (UVTs) (77 and 88%). The results showed that models that neglected the effects of refraction deviated significantly from the experimental data. In addition, the MSSS approach or models that incorporated the MSSS concept were found to best match the experimentally measured fluence rate distribution. Moreover, little difference was found between the results of MSSS with quartz sleeve thickness and UVCalc3D, which does not model the quartz sleeve thickness in the refraction angle calculation but uses a factor to account for the effects of the quartz sleeve on the fluence rate. The attenuation factor combined with the LSI model was found to match the MSSS model predictions, while reducing the computational cost. disinfection, fluence rate, model, spherical actinometry, UV This content is only available as a PDF. © IWA Publishing 2004 You do not currently have access to this content. DA - 2004/9// PY - 2004/9// DO - 10.2166/aqua.2004.0031 VL - 53 IS - 6 SP - 391-408 SN - 1365-2087 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-6344252713&partnerID=MN8TOARS KW - disinfection KW - fluence rate KW - model KW - spherical actinometry KW - UV ER - TY - JOUR TI - Comparison of sensitivity analysis methods based on applications to a food safety risk assessment model AU - Patil, , SR AU - Frey, HC T2 - RISK ANALYSIS AB - Sensitivity analysis (SA) methods are a valuable tool for identifying critical control points (CCPs), which is one of the important steps in the hazard analysis and CCP approach that is used to ensure safe food. There are many SA methods used across various disciplines. Furthermore, food safety process risk models pose challenges because they often are highly nonlinear, contain thresholds, and have discrete inputs. Therefore, it is useful to compare and evaluate SA methods based upon applications to an example food safety risk model. Ten SA methods were applied to a draft Vibrio parahaemolyticus (Vp) risk assessment model developed by the Food and Drug Administration. The model was modified so that all inputs were independent. Rankings of key inputs from different methods were compared. Inputs such as water temperature, number of oysters per meal, and the distributional assumption for the unrefrigerated time were the most important inputs, whereas time on water, fraction of pathogenic Vp, and the distributional assumption for the weight of oysters were the least important inputs. Most of the methods gave a similar ranking of key inputs even though the methods differed in terms of being graphical, mathematical, or statistical, accounting for individual effects or joint effect of inputs, and being model dependent or model independent. A key recommendation is that methods be further compared by application on different and more complex food safety models. Model independent methods, such as ANOVA, mutual information index, and scatter plots, are expected to be more robust than others evaluated. DA - 2004/6// PY - 2004/6// DO - 10.1111/j.0272-4332.2004.00460.x VL - 24 IS - 3 SP - 573-585 SN - 1539-6924 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3042765751&partnerID=MN8TOARS KW - complex models KW - critical control points KW - food safety KW - risk assessment KW - sensitivity analysis ER - TY - CHAP TI - Using arena for simulation of pedestrian crossing in roundabout areas AU - Wan, B. H. AU - Rouphail, N. M. T2 - Pedestrians and bicycles: Developing countries CN - TE7 .H5 no. 1878 PY - 2004/// SP - 58-65 PB - Washington, DC: Transportation Research Board SN - 0309094720 ER - TY - CHAP TI - Systematic approach for validating traffic simulation models AU - Ni, D. H. AU - Leonard, J. D. AU - Guin, A. AU - Williams, B. M. T2 - Calibration and validation of simulation models 2004 CN - TE7 .H5 no. 1876 PY - 2004/// SP - 20-31 PB - Washington, DC: Transportation Research Board SN - 0309094704 ER - TY - CHAP TI - Method for priority-ranking and expanding freeway service patrols AU - Khattak, A. AU - Rouphail, N. AU - Monast, K. AU - Havel, J. T2 - Freeway operations and traffic signal systems, 2004 CN - TE7 .H5 no. 1867 PY - 2004/// SP - 1-10 PB - Washington, DC: Transportation Research Board, National Academy of Sciences SN - 0309094615 ER - TY - CHAP TI - Determination of depth of surface cracks in asphalt pavements AU - Underwood, S. AU - Kim, Y. R. T2 - Pavement management and rigid and flexible pavement design 2003 AB - Nondestructive measurement of crack depths of asphalt pavements in situ could be a valuable tool for engineers in rehabilitation planning. Such measurements currently must be made by first coring or trenching a pavement and then measuring the crack by hand. Two methods for performing this task nondestructively are presented. The two methods, surface wave and ultrasonic, use the slowing effect that a crack has on a wave. Two signal-processing techniques were used to analyze the surface wave method—the fast Fourier transform (FFT) and the short kernel method (SKM). The FFT method provided a frequency spectrum that was used to find the energy carried by specific frequencies. The percent energy reduction (PER) was computed and plotted at each crack depth; this plot revealed that PER values increase as crack depth increases. The SKM method showed the wave velocity to decrease as the crack depth in creased. By comparing the wave velocity of the cracked pavement with that of the undamaged pavement, a phase velocity ratio plot was developed and was shown to be adequate for predicting crack depth. Ultrasonic testing proved to be a simpler and more direct method than surface wave testing. It was not necessary to know the wave properties of an undamaged pavement with this method, and a quantitative prediction of crack depth was obtained. While encouraging results were observed with both methods, ultrasonic testing showed the most promise for application because of the commercial availability of ultrasonic meters and the direct prediction of crack depth. CN - TE7 .H5 no.1853 PY - 2004/// DO - 10.3141/1853-16 SP - 143-149 PB - Washington, DC: Transportation Research Board ER - TY - JOUR TI - Concrete-filled steel tubes subjected to axial compression and lateral cyclic loads AU - Fam, A. AU - Qie, F. S. AU - Rizkalla, S. T2 - Journal of Structural Engineering (New York, N.Y.) AB - This paper presents an experimental work and analytical modeling for concrete-filled steel tubes (CFSTs) subjected to concentric axial compression and combined axial compression and lateral cyclic loading. The objective of the study is to evaluate the strength and ductility of CFST short columns and beam-column members under different bond and end loading conditions. Both bonded and unbonded specimens were tested, including application of the axial load to the composite steel-concrete section and to the concrete core only. Research findings indicate that the bond and end loading conditions did not affect the flexural strength of beam-column members significantly. On the other hand, the axial strengths of the unbonded short columns were slightly increased, compared to those of the bonded ones, while the stiffness of the unbonded specimens was slightly reduced. Test results were compared with the available design specifications, which were found to be conservative. The paper also presents an analytical model capable of predicting the flexural and axial load strength of CFST members. Experimental results were found to be in good agreement with the predicted values. DA - 2004/// PY - 2004/// DO - 10.1061/(asce)0733-9445(2004)130:4(631) VL - 130 IS - 4 SP - 631-640 ER - TY - JOUR TI - Biodegradation of 1,4-dioxane using trickling filter AU - Zenker, M. J. AU - Borden, R. C. AU - Barlaz, Morton T2 - Journal of Environmental Engineering (New York, N.Y.) AB - The ability of a laboratory-scale trickling filter to biodegrade cyclic ethers was investigated and a simple kinetic model was developed to predict ether biodegradation. The trickling filter received a feed solution designed to mimic ether concentrations typically encountered in contaminated groundwater. The reactor was operated for approximately 1 year and was capable of biodegrading 93–97% of 1,4-dioxane at various loading rates in the obligate presence of tetrahydrofuran (THF) as the growth substrate. A simple tanks-in-series hydraulic model combined with a kinetic model that incorporated cometabolism was utilized to simulate removal of THF and 1,4-dioxane. Model simulations of THF removal were satisfactory for all loading rates analyzed. However, the model somewhat over predicted 1,4-dioxane removal. This research demonstrates the ability to treat groundwater contaminated with low concentrations of ethers in attached growth reactors. DA - 2004/// PY - 2004/// DO - 10.1061/(asce)0733-9372(2004)130:9(926) VL - 130 IS - 9 SP - 926–931 ER - TY - JOUR TI - Assessment of the computing component of civil engineering education AU - Abudayyeh, O. AU - Cai, H. B. AU - Fenves, S. J. AU - Law, K. AU - O'Neill, R. AU - Rasdorf, W. T2 - Journal of Computing in Civil Engineering AB - This paper presents the results of two surveys conducted by the American Society of Civil Engineers’ Task Committee on Computing Education of the Technical Council on Computing and Information Technology to assess the current computing component of the curriculum in civil engineering. Previous surveys completed in 1989 and 1995 have addressed the question of what should be taught to civil engineering students regarding computing. The surveys reported in this paper are a follow-up study to the two earlier surveys. Key findings of the study include: (1) the relative importance of the top four skills (spreadsheets, word processors, computer aided-design, electronic communication) has remained unchanged; (2) programming competence is ranked very low by practitioners; (3) the importance and use of geographic information system and specialized engineering software have increased over the past decade; (4) the importance and use of expert systems have significantly decreased over the past decade; and (5) the importance and use of equation solvers and databases have declined over the past decade. DA - 2004/// PY - 2004/// DO - 10.1061/(ASCE)0887-3801(2004)18:3(187) VL - 18 IS - 3 SP - 187-195 ER - TY - CHAP TI - Assessing uncertainties in traffic simulation: A key component in model calibration and validation AU - Bayarri, M. J. AU - Berger, J. O. AU - Molina, G. AU - Rouphail, N. M. AU - Sacks, J. T2 - Calibration and validation of simulation models 2004 CN - TE7 .H5 no. 1876 PY - 2004/// SP - 32-40 PB - Washington, DC: Transportation Research Board SN - 0309094704 ER - TY - JOUR TI - Transient analysis of linear birth-death processes with immigration and emigration AU - Zheng, Y. X. AU - Chao, X. L. AU - Ji, X. M. T2 - Probability in the Engineering and Informational Sciences AB - Linear birth–death processes with immigration and emigration are major models in the study of population processes of biological and ecological systems, and their transient analysis is important in the understanding of the structural behavior of such systems. The spectral method has been widely used for solving these processes; see, for example, Karlin and McGregor [11]. In this article, we provide an alternative approach: the method of characteristics. This method yields a Volterra-type integral equation for the chance of extinction and an explicit formula for the z -transform of the transient distribution. These results allow us to obtain closed-form solutions for the transient behavior of several cases that have not been previously explicitly presented in the literature. DA - 2004/// PY - 2004/// DO - 10.1017/s0269964804182016 VL - 18 IS - 2 SP - 141-159 ER - TY - JOUR TI - Propagation of uncertainty in hourly utility NOx emissions through a photochemical grid air quality model: A case study for the Charlotte, NC, modeling domain AU - Abdel-Aziz, A AU - Frey, HC T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - One of the major hypothesized sources of uncertainties in air quality model inputs is the emission inventory. A probabilistic hourly NOx emission inventory for 32 units of nine coal-fired power plants in the Charlotte domain for the year 1995 was propagated through the Multiscale Air Quality Simulation Platform (MAQSIP). The inventory was developed using time series techniques. Time series for a 4-d episode were simulated and propagated through the air quality model 50 times in order to represent the ranges of uncertainty in hourly emissions and predicted ozone levels. Intra-unit autocorrelation in emissions and inter-unit dependence were accounted for. The range of uncertainty in predicted ozone was greater when inter-unit dependence was included as compared to when units were treated as statistically independent. Uncertainties in maximum ozone hourly or 8-h concentrations at a specific location could be attributed to a specific power plant based upon regression analysis. Out of 3969 grid cells in the modeling domain, there were 43 and 1654 grid cells with a probability greater than 0.9 of exceeding a 1-h 120 ppb standard and an 8-h 80 ppb standard, respectively. The time series of predicted ozone values had similar autocorrelation as compared to monitored data. The implications of these results for air quality management are addressed. DA - 2004/4/1/ PY - 2004/4/1/ DO - 10.1021/es034062b VL - 38 IS - 7 SP - 2153-2160 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1842779078&partnerID=MN8TOARS ER - TY - JOUR TI - Modeling low-energy mixers for chemical dispersion in water treatment AU - Ortiz, V AU - Ducoste, JJ T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - A study has been conducted to evaluate the use of computational fluid dynamics (CFD) for analyzing the mixing effectiveness of low-energy mixers in water and wastewater treatment processes. In this study, CFD was used to predict experimental downstream mean tracer concentration and segregation intensity in different closed conduit reactor geometries. Mixing configurations include a plane shear layer, plane jet in a square conduit, a round jet in a circular conduit, and a hydraulic jet in a 1- and 6-in. diameter pipe. Tracer transport was approximated as a single fluid with the standard k-ε, Chen-Kim k-ε, RNG k-ε turbulence models and as a multifluid with the standard k-ε turbulence model. The results showed that the multifluid model better predicted the mean concentration than the single-fluid model. Multifluid model r2 values were significantly higher than the single-fluid model r2 values. The multifluid model also predicted the downstream segregation intensity values for the plane jet and round jet configurations. In addition, the multifluid model was able to predict the degradation in mixing performance moving from the 1- to 6-in. diameter hydraulic jet mixers operating under constant-jet momentum ratio. No significant improvement was found in the single-fluid model predictions by changing the turbulence model. Overall, the results show that CFD has the potential to enhance engineering experience by permitting the evaluation of different low energy-mixer alternatives. DA - 2004/// PY - 2004/// DO - 10.1089/109287504773087408 VL - 21 IS - 2 SP - 241-261 SN - 1557-9018 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1542513928&partnerID=MN8TOARS KW - CFD KW - chemical mixing KW - turbulence KW - modeling ER - TY - JOUR TI - Design for torsion and shear in prestressed concrete flexural members, II AU - Zia, P. AU - Hsu, T. T. C. T2 - PCI Journal DA - 2004/// PY - 2004/// VL - 49 IS - 6 SP - 132 ER - TY - JOUR TI - Design for torsion and shear in prestressed concrete flexural members - Author's closure AU - Zia, P. AU - Hsu, T. T. C. T2 - PCI Journal DA - 2004/// PY - 2004/// VL - 49 IS - 6 SP - 132 ER - TY - JOUR TI - Decolorizing of lignin wastewater using the photochemical UV/TiO2 process AU - Chang, CN AU - Ma, YS AU - Fang, GC AU - Chao, AC AU - Tsai, MC AU - Sung, HF T2 - CHEMOSPHERE AB - Studies on applying the photochemical UV/TiO2 oxidation process to treat the lignin-containing wastewater for dissolved organic carbon (DOC), color and reducing A254 (the absorption at the wavelength of 254 nm) have been carried out. The data obtained in this study demonstrate that the UV/TiO2 process is effective in oxidizing the lignin thus reducing the color and DOC of the wastewater treated. The combined UV/TiO2 treatment can achieve better removal of DOC and color than the UV treatment alone. Color removal, based on American Dye Manufacture Index (ADMI) measurement, is greater than 99% if the pH is maintained at 3.0 with the addition of 1 g l(-1) TiO2. When 10 g l(-1) TiO2 is applied, the oxidation reduction potential (ORP) value is reached to result in an 88% removal of both DOC and color. A model was developed based on the variation of ORP during the photochemical reaction to simulate the decoloring process. The proposed model can be used to predict the color removal efficiency of the UV/TiO2 process. DA - 2004/9// PY - 2004/9// DO - 10.1016/j.chemosphere.2004.04.021 VL - 56 IS - 10 SP - 1011-1017 SN - 1879-1298 KW - photochemical oxidation KW - color removal KW - ADMI KW - DOC KW - ORP ER - TY - JOUR TI - Applying the nernst equation to simulate redox potential variations for biological nitrification and denitrification processes AU - Chang, CN AU - Cheng, HB AU - Chao, AC T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - In this paper, various forms of Nernst equations have been developed based on the real stoichiometric relationship of biological nitrification and denitrification reactions. Instead of using the Nernst equation based on a one-to-one stoichiometric relation for the oxidizing and the reducing species, the basic Nernst equation is modified into slightly different forms. Each is suitable for simulating the redox potential (ORP) variation of a specific biological nitrification or denitrification process. Using the data published in the literature, the validity of these developed Nernst equations has been verified by close fits of the measured ORP data with the calculated ORP curve. The simulation results also indicate that if the biological process is simulated using an incorrect form of Nernst equation, the calculated ORP curve will not fit the measured data. Using these Nernst equations, the ORP value that corresponds to a predetermined degree of completion for the biochemical reaction can be calculated. Thus, these Nernst equations will enable a more efficient on-line control of the biological process. DA - 2004/3/15/ PY - 2004/3/15/ DO - 10.1021/es021088e VL - 38 IS - 6 SP - 1807-1812 SN - 1520-5851 ER - TY - JOUR TI - A non-biological surrogate for sequential disinfection processes AU - Baeza, C AU - Ducoste, J T2 - WATER RESEARCH AB - An evaluation of Fluorescent YG-microspheres (Polysciences Inc.) was performed to simulate Cryptosporidium parvum (C. parvum) oocysts inactivation in treatment systems that utilize multiple disinfectants. Experiments were conducted in batch reactors that included an ozone primary stage and a secondary free chlorine treatment stage. A flow cytometer was used to track changes in the fluorescence intensity distribution due to exposure to the chemical disinfectant. Microsphere ‘survival ratios’ (N/No) were calibrated by selecting an appropriate fluorescence intensity threshold to replicate the inactivation of different C. parvum oocysts strains. Results showed that fluorescent microspheres displayed synergistic effects in the presence of two sequential disinfectants. In addition, microsphere structural tests showed that the polystyrene surface was damaged due to exposure to ozone. This polystyrene damage enhanced the diffusion of the secondary disinfectant into the microsphere, where dye was degraded in the opened polymer layer. As a result, YG-fluorescent microspheres is a promising non-biological technique that is capable of producing similar synergistic behavior as with C. parvum oocysts exposed to ozone followed by chlorine. DA - 2004/// PY - 2004/// DO - 10.1016/j.watres.2004.04.029 VL - 38 IS - 14-15 SP - 3400-3410 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3342922732&partnerID=MN8TOARS KW - Crymosporidium parvum KW - free chlorine KW - microspheres KW - non-biological surrogate KW - ozone KW - sequential disinfection ER - TY - JOUR TI - Relationship between particle shape and void content of fine aggregate AU - Dilek, U. AU - Leming, M. L. T2 - Cement, Concrete and Aggregates AB - Fine aggregate characteristics have an important influence on water demand and related properties of concrete. Several test methods for measurement of fine aggregate angularity are reported in the literature. These tests typically provide a single number that represents the bulk, or average angularity of the sand. An understanding of the relationship between bulk measures of angularity, individual particle geometry and shape characteristics, and concrete properties is important to aggregate producers, concrete suppliers, consulting engineers, other design professionals, particularly as existing deposits of sand are consumed and alternate sources must be developed. As part of a comprehensive research program on manufactured sand properties and their effects on fresh and hardened concrete properties, an image analysis technique was developed to determine the shape characteristics by photographing and analyzing sets of individual grains of sand. The outlines of the grains were analyzed using a variety of geometrically derived characteristics. The relationship between particle shape characteristics and a common measure of bulk angularity, void content (ASTM C 1252), was then examined. Results of the study indicated that void content was significantly influenced by the presence of deep indentations in the surface of the sand particle and deviations from a cubical particle shape. DA - 2004/// PY - 2004/// DO - 10.1520/cca11916 VL - 26 IS - 1 SP - 14-20 ER - TY - JOUR TI - Modeling the dynamic behavior of electrical cabinets and control panels: Experimental and analytical results AU - Rustogi, S. K. AU - Gupta, A. T2 - Journal of Structural Engineering (New York, N.Y.) AB - Ritz vector approach for evaluating the dynamic properties of electrical cabinets is based on the premise that a single significant cabinet mode is sufficient to calculate accurate incabinet spectra needed in the seismic qualification of electrical instruments mounted inside the cabinet. It uses mathematical functions to characterize the significant mode shapes that can be either a local mode shape of the structural member or a superposition of the global cabinet and the local mode shapes. The significant modes for typical cabinets have been identified from fixed-base finite element analyses. In this paper, modal data from in situ and shake table tests for two different cabinets is used to evaluate not only the validity of finite element analysis results but also the premise for developing Ritz vector approach. A key difference observed in the test data is related to the existence of a global rocking in cabinets that are anchored at the base. A rigid body rocking due to base plate uplift cannot be evaluated from fixed-base finite element models that were used in the development of the Ritz vector approach. Finite element analyses after modifications for incorporating cabinet rocking due to base plate uplifting give results that are close to the test data. Even though the test data and the new analyses show that the significant cabinet mode is different from what has been considered in the past, the basic premise for Ritz vector approach remains unchanged. Minor modifications needed in the Ritz vector approach for incorporating cabinet rocking superimposed with local mode shapes are also presented. DA - 2004/// PY - 2004/// DO - 10.1061/(asce)0733-9445(2004)130:3(511) VL - 130 IS - 3 SP - 511-519 ER - TY - JOUR TI - Impact of edible oil injection on the permeability of aquifer sands AU - Coulibaly, KM AU - Borden, RC T2 - JOURNAL OF CONTAMINANT HYDROLOGY AB - Recent laboratory and field studies have shown that food-grade edible oils can be injected into the subsurface for installation of in-situ permeable reactive barriers. However to be effective, the oil must be distributed out away from the oil injection points without excessive permeability loss. In this work, we examine the distribution of soybean oil in representative aquifer sediments as non-aqueous phase liquid oil (NAPL oil) or as an oil-in-water emulsion. Laboratory columns packed with sands or clayey sands were flushed with either NAPL oil or a soybean emulsion followed by plain water, while monitoring permeability loss and the final oil residual saturation. NAPL oil can be injected into coarse-grained sands. However NAPL injection into finer grained sediments requires high injection pressures which may not be feasible at some sites. In addition, NAPL injection results in high oil residual saturations and moderate permeability losses. In contrast, properly prepared emulsions can be distributed through sands with varying clay content without excessive pressure buildup, low oil retention and very low to moderate permeability loss. For effective transport, the emulsion must be stable, the oil droplets must be significantly smaller than the mean pore size of the sediment and the oil droplets should have a low to moderate tendency to stick to each other and the aquifer sediments. In our work, oil retention and associated permeability loss increased with sediment clay content and with the ratio of droplet size to pore size. For sandy sediments, the permeability loss is modest (0–40% loss) and is proportional to the oil residual saturation. DA - 2004/7// PY - 2004/7// DO - 10.1016/j.jconhyd.2003.10.002 VL - 71 IS - 1-4 SP - 219-237 SN - 0169-7722 KW - edible oil KW - anaerobic bioremediation KW - emulsion KW - permeability ER - TY - JOUR TI - Accuracy assessment of interstate highway length using digital elevation model AU - Rasdorf, W. AU - Cai, H. AU - Tilley, C. AU - Brun, S. AU - Robson, F. T2 - Journal of Surveying Engineering AB - Road length is part of the geometry of the roadway network. Its measurement is critical to all road inventory databases. One approach to obtaining it is to drive cars equipped with a distance measurement instrument (DMI) along roads to measure mileages. This method provides accurate measurements, but it is expensive and time consuming. This paper proposes an alternative way to acquire actual road length, which is currently under consideration by the geographic information system (GIS) unit of the North Carolina Department of Transportation. The emphasis of this study was to determine the accuracy of the proposed approach. The proposed approach employs GIS application programs written in ARC macro language to calculate the actual length (surface length) along the sloped surface of highway centerlines based on elevation data and the road network geometry. This was done for all interstate highways in North Carolina. The calculated GIS results were compared with DMI measurements, which is the most accurate approach presently available to NCDOT. Three filters were applied to remove suspect road segments that have significant errors which are irrelevant to the proposed approach. All remaining segments were grouped by slope and length to evaluate the impact of slope and length on the accuracy. Frequency analysis and root mean square error were determined for all groups. It was found that the proposed method is a technically feasible method with reasonable accuracy. The study also revealed that where there are errors, they occur primarily for road segments with relatively high slopes, short lengths, or both. The meaning of this is that GIS and digital elevation model technologies can be combined and used in lieu of DMI measurements, thus reducing resource demands. DA - 2004/// PY - 2004/// DO - 10.1061/(ASCE)0733-9453(2004)130:3(142) VL - 130 IS - 3 SP - 142-150 ER - TY - JOUR TI - A high resolution computer model for sound propagation in the human thorax based on the Visible Human data set AU - Narasimhan, C AU - Ward, R AU - Kruse, KL AU - Guddati, M AU - Mahinthakumar, G T2 - COMPUTERS IN BIOLOGY AND MEDICINE AB - A parallel supercomputer model based on realistic tissue data is developed for sound propagation in the human thorax and the sound propagation behavior is analyzed under various conditions using artificial sound sources. The model uses the Visible Human®1 male data set for a realistic representation of the human thorax. The results were analyzed in time and frequency domains. The analysis suggests that lower frequencies of around 100Hz are more effectively transmitted through the thorax and that the spatial confinement of sound waves within the thorax results in a resonance effect at around 1500Hz. The results confirm previous studies that show the size of the thorax plays a significant role in the type of sound generated at the chest wall. DA - 2004/3// PY - 2004/3// DO - 10.1016/S0010-4825(03)00044-1 VL - 34 IS - 2 SP - 177-192 SN - 1879-0534 KW - sound propagation KW - human thorax KW - visible human data set KW - parallel computing ER - TY - JOUR TI - Stability and dynamics of Pt-Si liquid microdroplets on Si(001) AU - Yang, WC AU - Ade, H AU - Nemanich, RJ T2 - PHYSICAL REVIEW B AB - The formation and dynamics of Pt-Si liquid droplets on Si (001) surfaces are explored with real-time ultraviolet photoelectron emission microscopy. PtSi islands of micrometer lateral diameter begin to melt and are transformed into molten Pt-Si alloy islands below the melting point of bulk PtSi. In particular, at $\ensuremath{\sim}1100\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ surface migration of the liquid microdroplets is observed, where the droplets move directionally from the cold to the hot regions of the surface following the temperature gradient across the substrate. It is proposed that the droplet surface migration is due to dissolution-diffusion-deposition flow of Si through the droplet driven by the Si concentration difference in the droplet. In addition, the migration rate of the droplet is measured as a function of temperature and droplet diameter. Above a minimum diameter, the migration velocity is independent of the droplet size, which indicates that Si diffusivity through the droplet is the primary factor determining the rate of migration. The activation energy for the Si diffusion in the droplet is found to be $\ensuremath{\sim}0.57\mathrm{eV}.$ We conclude that the thermal and chemical stability of the droplet-substrate interface significantly affects the evolution and dynamics of the liquid island on the surface. DA - 2004/1// PY - 2004/1// DO - 10.1103/physrevb.69.045421 VL - 69 IS - 4 SP - SN - 2469-9969 ER - TY - JOUR TI - SMiRT 16 - Selected and updated papers from the 16th International Conference on Structural Mechanics in Reactor Technology - Washington, DC - Preface AU - Matzen, VC T2 - NUCLEAR ENGINEERING AND DESIGN DA - 2004/3// PY - 2004/3// DO - 10.1016/j.nucengdes.2003.09.004 VL - 228 IS - 1-3 SP - 1-1 SN - 0029-5493 ER - TY - JOUR TI - Reversed in-plane cyclic behavior of posttensioned clay brick masonry walls AU - Rosenboom, O. A. AU - Kowalsky, M. J. T2 - Journal of Structural Engineering (New York, N.Y.) AB - A series of five large scale clay brick masonry structural walls are subjected to in-plane simulated seismic forces. The walls utilize posttensioning steel to provide flexural strength. The primary objective of the research is to investigate five basic configurations of posttensioning to determine which has the most desirable characteristics for seismic performance. In the study, the variables of interest were (1) bonded versus unbonded posttensioning steel, (2) confined versus unconfined masonry, (3) grouted versus ungrouted masonry, and (4) application of supplemental mild steel for energy dissipation. Following the results of the tests, it was shown that the best performing configuration utilized unbonded posttensioning and confinement. By utilizing unbonded posttensioning, walls have little residual deformation after loading, thus yielding structures that would require very little repair, even after large seismic events. Such behavior comes with the price of reduced energy dissipation, however. Presented in the paper are the results of the tests as well as results of a simple analysis method for prediction of wall capacity. DA - 2004/// PY - 2004/// DO - 10.1061/(asce)0733-9445(2004)130:5(787) VL - 130 IS - 5 SP - 787-798 ER - TY - JOUR TI - Relationship of species-specific filament levels to filamentous bulking in activated sludge AU - Liao, J. Y. AU - Lou, I. C. AU - De Los Reyes, F. L. T2 - Applied and Environmental Microbiology DA - 2004/// PY - 2004/// DO - 10.1028/AEM.70.4.2420-2428.2004 VL - 70 IS - 4 SP - 2420–2428 UR - https://publons.com/wos-op/publon/15001845/ ER - TY - JOUR TI - Quantification of highway vehicle emissions hot spots based upon on-board measurements AU - Unal, A AU - Frey, HC AU - Rouphail, NM T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - The purpose of this study is to demonstrate a methodology for quantification of high emissions hot spots along roadways based upon real-world, on-road vehicle emissions measurements. An emissions hot spot is defined as a fixed location along a corridor in which the peak emissions are statistically significantly greater by more than a factor of 2 than the average emissions for free-flow or near free-flow conditions on the corridor. A portable instrument was used to measure on-road tailpipe emissions of carbon monoxide, nitric oxide, hydrocarbons, and carbon dioxide on a second-by-second basis during actual driving. Measurements were made for seven vehicles deployed on two primary arterial corridors. The ratio of average emissions at hot spots to the average emissions observed during a trip was as high as 25 for carbon monoxide, 5 for nitric oxide, and 3 for hydrocarbons. The relationships between hot spots and explanatory variables were investigated using graphical and statistical methods. Average speed, average acceleration, standard deviation of speed, percent of time spent in cruise mode, minimum speed, maximum acceleration, and maximum power have statistically significant associations with vehicle emissions and influence emissions hot spots. For example, stop-and-go traffic conditions that result in sudden changes in speed, and traffic patterns with high accelerations, are shown to generate hot spots. The implications of this work for future model development and applications to environmental management are discussed. DA - 2004/2// PY - 2004/2// DO - 10.1080/10473289.2004.10470888 VL - 54 IS - 2 SP - 130-140 SN - 2162-2906 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0942265487&partnerID=MN8TOARS ER - TY - BOOK TI - Construction methods and management (6th ed.) AU - Nunnally, S. W. CN - TH145 .N86 2004 DA - 2004/// PY - 2004/// PB - Upper Saddle River, NJ: Pearson Prentice Hall SN - 0130482218 ER - TY - JOUR TI - Nonlinear cyclic response of laminated glass FRP tubes filled with concrete AU - Shao, Y AU - Mirmiran, A T2 - COMPOSITE STRUCTURES AB - Fiber reinforced polymer (FRP) materials are generally known for their linear elastic response to failure. The present study evaluated the implications of using FRP as primary and sole reinforcement for concrete structures in seismic regions through an experimental and analytical investigation on the cyclic response of two different types of laminated glass FRP tubes filled with concrete. The study showed that concrete-filled tubes can be designed with an appropriate laminate structure for a ductility level comparable to that of conventional reinforced concrete columns. The nonlinearity and ductility in these types of structures stem from the off-axis response of the FRP tube. A hysteretic model was developed for the tube, and was cast into a two-dimensional three-node combined fiber element for the concrete-filled FRP tube. Good agreement was shown between the analytical models and the experimental results. DA - 2004/7// PY - 2004/7// DO - 10.1016/j.compstruct.2003.10.009 VL - 65 IS - 1 SP - 91-101 SN - 1879-1085 KW - composite tube KW - cyclic loading KW - ductility KW - fiber orientation KW - nonlinearity ER - TY - JOUR TI - Molecular methods in biological systems AU - Reyes, FL AU - Oerther, DB AU - Angenent, LT T2 - WATER ENVIRONMENT RESEARCH AB - Water Environment ResearchVolume 76, Issue 6 p. 605-667 Monitoring and MeasurementFree Access Molecular Methods in Biological Systems Francis L. de los Reyes III, Francis L. de los Reyes IIISearch for more papers by this authorDaniel B. Oerther, Daniel B. OertherSearch for more papers by this authorLargus T. Angenent, Largus T. AngenentSearch for more papers by this author Francis L. de los Reyes III, Francis L. de los Reyes IIISearch for more papers by this authorDaniel B. Oerther, Daniel B. OertherSearch for more papers by this authorLargus T. Angenent, Largus T. AngenentSearch for more papers by this author First published: 01 October 2004 https://doi.org/10.2175/106143004X141988AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Volume76, Issue62004 Literature ReviewSeptember-October 2004Pages 605-667 RelatedInformation DA - 2004/// PY - 2004/// DO - 10.2175/106143004X141988 VL - 76 IS - 6 SP - 605-667 SN - 1554-7531 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-39349097829&partnerID=MN8TOARS ER - TY - JOUR TI - Bioreactor landfills: progress continues AU - Barlaz, MA AU - Reinhart, D T2 - WASTE MANAGEMENT AB - Landfill bioreactors are based on an acceleration of in-situ waste biodegradation by performing leachate recirculation. To quantify the water content and to evaluate the leachate injection system, in-situ methods are required to obtain spatially distributed information, usually electrical resistivity tomography (ERT). In a previous study, the MICS (multiple inversions and clustering strategy) methodology was proposed to improve the hydrodynamic interpretation of ERT results by a precise delimitation of the infiltration area. In this study, MICS was applied on two ERT time-lapse data sets recorded on different waste deposit cells in order to compare the hydrodynamic behaviour of leachate flow between the two cells. This comparison is based on an analysis of: (i) the volume of wetted waste assessed by MICS and the wetting rate, (ii) the infiltration shapes and (iii) the pore volume used by the leachate flow. This paper shows that leachate hydrodynamic behaviour is comparable from one waste deposit cell to another with: (i) a high leachate infiltration speed at the beginning of the infiltration, which decreases with time, (ii) a horizontal anisotropy of the leachate infiltration shape and (iii) a very small fraction of the pore volume used by the leachate flow. This hydrodynamic information derived from MICS results can be useful for subsurface flow modelling used to predict leachate flow at the landfill scale. DA - 2004/// PY - 2004/// DO - 10.1016/j.wasman.2004.09.001 VL - 24 IS - 9 SP - 859-860 SN - 0956-053X ER - TY - JOUR TI - On the onset of necking in the tensile test AU - Havner, KS T2 - INTERNATIONAL JOURNAL OF PLASTICITY AB - A very small inhomogeneity in macroscopic material properties is considered for the investigation of necking of a (polycrystalline) bar in the tensile test. A simple, one-dimensional model is adopted (i.e. spatial variation only along the bar's length), corresponding to which the evolving nonuniformity of cross-sectional area with increasing load, up to the maximum, also is small. The inhomogeneity is represented by a single modulus varying slightly with position, but with the same dimensionless form of the stress–strain curve throughout. A transcendental equation is derived that relates the strains at the weakest and strongest sections to their respective material strengths. It is shown that, at the well known Considère strain (corresponding to the maximum load), the decrease in area at the minimum section is only a little greater than at the strongest, but its rate of change with the latter strain is infinite. The analysis thus gives an idealized representation of the rapid increase in necking that typically ensues from the maximum load in experiments. In an extended Appendix the traditional case of a bar of theoretically homogeneous material is reviewed and reanalyzed, including consideration of rate-dependence. DA - 2004/// PY - 2004/// DO - 10.1016/j.ijplas.2003.05.004 VL - 20 IS - 4-5 SP - 965-978 SN - 0749-6419 KW - tensile test KW - analysis of necking KW - macroscopic material inhomogeneity ER -