TY - JOUR TI - Detection and quantification of an environmentally versatile Bacillus strain using hybridization probes targeting the 16S rRNA and 16S-23S rRNA spacer region T2 - Abstracts of the General Meeting of the American Society for Microbiology DA - 2002/// PY - 2002/// UR - https://publons.com/wos-op/publon/15001862/ ER - TY - JOUR TI - Comparison of parametric and nonparametric models for traffic flow forecasting AU - Smith, B.L. AU - Williams, B.M. AU - Keith Oswald, R. T2 - Transportation Research Part C: Emerging Technologies AB - Single point short-term traffic flow forecasting will play a key role in supporting demand forecasts needed by operational network models. Seasonal autoregressive integrated moving average (ARIMA), a classic parametric modeling approach to time series, and nonparametric regression models have been proposed as well suited for application to single point short-term traffic flow forecasting. Past research has shown seasonal ARIMA models to deliver results that are statistically superior to basic implementations of nonparametric regression. However, the advantages associated with a data-driven nonparametric forecasting approach motivate further investigation of refined nonparametric forecasting methods. Following this motivation, this research effort seeks to examine the theoretical foundation of nonparametric regression and to answer the question of whether nonparametric regression based on heuristically improved forecast generation methods approach the single interval traffic flow prediction performance of seasonal ARIMA models. DA - 2002/// PY - 2002/// DO - 10.1016/S0968-090X(02)00009-8 VL - 10 IS - 4 SP - 303-321 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036692982&partnerID=MN8TOARS ER - TY - CONF TI - Modeling Toluene Desorption from Municipal Solid Waste Components AU - Wu, B. AU - Knappe, D.R.U. AU - Barlaz, M.A. T2 - Fall Meeting of the American Geophysical Union C2 - 2002/// CY - San Francisco, CA DA - 2002/// PY - 2002/12/6/ ER - TY - CONF TI - Factors Controlling Alkylbenzene Sorption and Desorption to Municipal Solid Waste AU - Wu, B. AU - Knappe, D.R.U. AU - Barlaz, M.A. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Factors Affecting the Bioavailability of Tetrachloroethene Sorbed to Municipal Solid Waste Components AU - Zhang, Z. AU - Barlaz, M.A. AU - Knappe, D.R.U. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Interactions between Hydrophobic Organic Contaminants and Dissolved Organic Matter in Methanogenic Leachate AU - Knappe, D.R.U. AU - Zhang, Z. AU - Hoyle, L.E. AU - Barlaz, M.A. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Production of Non-Methane Organic Compounds (NMOCs) During the Decomposition of Refuse and Individual Waste Components Under Various Operating Conditions AU - Cowie, S.J. AU - Ihnatolya, J.C. AU - Hater, G.R. AU - Barlaz, M.A. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Development of Model Parameters for Prediction of Methane Production from Paper Industry Landfills AU - Maltby, C.V. AU - Barlaz, M.A. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Long-Term Nitrogen Management in Bioreactor Landfills AU - Barlaz, M.A. AU - Hater, G.R. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Effect of Aging on Bioavailability of Toluene Sorbed to Municipal Solid Waste Components AU - Chen, Y. AU - Barlaz, M.A. AU - Knappe, D.R.U. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - Shear Strength Parameters of Municipal Solid Waste with Leachate Recirculation AU - Gabr, M. AU - Houssain, M.S. AU - Barlaz, M.A. T2 - Second Intercontinental Landfill Research Symposium C2 - 2002/// CY - Asheville, NC DA - 2002/// PY - 2002/10/13/ ER - TY - CONF TI - The Use of Large Static Chambers to Compare Gaseous Emissions from a Traditional Soil Cover and a Biologically Active Cover at the Outer Loop Landfill AU - Green, R.B. AU - Hater, G.R. AU - Goldsmith, C.D. AU - Chanton, J. AU - Vogt, W.G. AU - Barlaz, M.A. T2 - 7th Annual Solid Waste Association of North America (SWANA) Landfill Symposium C2 - 2002/// CY - Louisville, KY DA - 2002/// PY - 2002/6/17/ ER - TY - CONF TI - Long-Term Nitrogen Management in Bioreactor Landfills AU - Barlaz, M.A. AU - Price, G.A. AU - Hater, G. T2 - Waste Tech C2 - 2002/// CY - Coral Springs, FL DA - 2002/// PY - 2002/2/24/ ER - TY - RPRT TI - ASTM D6776-02, Standard Test Method for Determining Anaerobic Biodegradability of Radiolabeled Plastic Materials in a Laboratory-Scale Simulated Landfill Environment AU - Barlaz, M.A. A3 - ASTM International DA - 2002/// PY - 2002/// M1 - 6776 – 02 PB - ASTM International SN - 6776 – 02 ER - TY - CONF TI - Methane Emissions from Municipal Solid Waste AU - Barlaz, M.A. T2 - North American Carbon Program C2 - 2002/// CY - University of New Hampshire, Durham, NH DA - 2002/// PY - 2002/9/10/ ER - TY - CONF TI - Comparing the Environmental Performance of Bioreactor and Traditional Landfills Using Life-Cycle Analysis AU - Barlaz, M.A. T2 - Solid Waste Association of North America (SWANA) Applied Research Foundation Project Planning Meeting, West Palm C2 - 2002/// CY - West Palm Spring, FL DA - 2002/// PY - 2002/1/16/ ER - TY - SOUND TI - Designing and Operating Bioreactor Landfills AU - Barlaz, M.A. DA - 2002/// PY - 2002/// M3 - workshop ER - TY - CONF TI - A Critical Evaluation of Factors Required to Terminate the Post-Closure Monitoring Period at Solid Waste Landfills AU - Barlaz, M.A. T2 - Solid Waste Association of North America (SWANA) Applied Research Foundation Project Planning Meeting C2 - 2002/// CY - West Palm Spring, FL DA - 2002/// PY - 2002/1/16/ ER - TY - CONF TI - Modeling Drinking Water UV Disinfection Reactors using PHOENICS: Comparison between Eulerian and Lagrangian Approach AU - Ducoste, J.J. AU - Liu, D. AU - Linden, K. T2 - Phoenics User Conference C2 - 2002/// C3 - Proceedings, Phoenics User Conference CY - Moscow, Russia DA - 2002/// PY - 2002/9/21/ ER - TY - CONF TI - Characterizing The Spatial Variation In Particle Aggregation Due To Heterogeneous Turbulence In A Flocculation Reactor AU - Hopkins, C. AU - Ducoste, J.J. T2 - North Carolina American Water Works Association / Water Environment Federation (NC AWWA/WEF) Annual Conference C2 - 2002/// CY - Winston-Salem, NC DA - 2002/// PY - 2002/11/17/ ER - TY - CONF TI - Determination of fluence rate distribution in UV reactors using spherical actinometry and mathematical analysis approaches AU - Jin, S. AU - Ducoste, J.J. AU - Linden, K.G. T2 - American Water Works Association Water Quality Technology Conference C2 - 2002/// C3 - Proceedings American Water Works Association WQTC Conference CY - Seattle, WA DA - 2002/// PY - 2002/11/10/ ER - TY - SOUND TI - A Multifluid Modeling Approach to Characterizing Chemical Dispersion in Drinking Water Treatment AU - Ducoste, J.J. AU - Ortiz, V. AU - Liu, Y. DA - 2002/// PY - 2002/// ER - TY - CONF TI - Use of Design Scenarios and Chance-Constrained Genetic Algorithm for Wastewater Treatment Plant Design AU - Doby, T. AU - Loughlin, D. AU - de los Reyes, F. AU - Ducoste, J.J. T2 - Environmental & Water Resources Systems, Analysis (EWRSA) Symposium C2 - 2002/// C3 - Environmental & Water Resources Systems, Analysis (EWRSA) Symposium, in conjunction with the Water EWRI Conference CY - Roanoke, Virginia, USA DA - 2002/// PY - 2002/5/19/ ER - TY - CONF TI - An Alternative Approach to Determining Dose Distribution and Microbial Inactivation in UV Reactors using Computational Fluid Dynamics (CFD) AU - Ducoste, J.J. AU - Linden, K. T2 - American Water Works Association National Conference C2 - 2002/// C3 - Proceedings American Water Works Association National Conference CY - New Orleans, LA DA - 2002/// PY - 2002/6/17/ ER - TY - JOUR TI - Confinement Model for Axially Loaded Concrete Confined by Circular Fiber-Reinforced Polymer Tubes: Discussion and Closure AU - Fam, A. AU - Rizkalla, S. T2 - ACI Structural Journal DA - 2002/5// PY - 2002/5// VL - 99 IS - 3 SP - 386–390 ER - TY - CONF TI - Evaluation of the Constraint Method-Based Multiobjective Evolutionary Algorithm (CMEA) for a Three-Objective Optimization Problem AU - Kumar, S.V. AU - Ranjithan, S. T2 - Genetic and Evolutionary Computation Conference, GECCO 2002 A2 - Langdon, WB A2 - Cantu-Paz, E A2 - Mathias, K A2 - Roy, R A2 - Davis, D A2 - Poli, R A2 - Balakrishnan, K A2 - Honavar, V A2 - Rudolph, G A2 - Wegener, J A2 - Bull, L A2 - Potter, MA A2 - Schultz, AC A2 - Miller, JF A2 - Burke, E A2 - Jonoska, N C2 - 2002/7/9/ C3 - Proceedings of the Genetic and Evolutionary Computation Conference, GECCO 2002 CY - New York DA - 2002/7/9/ PY - 2002/7/9/ SP - 431–438 PB - Morgan Kaufmann ER - TY - SOUND TI - Hydroclimatology of the United States AU - Arumugam, S. DA - 2002/5// PY - 2002/5// ER - TY - CONF TI - From Interannual Streamflow Forecasts to New Water Management Strategies for Ceara, North East Brazil AU - Lall, U. AU - Sharma, A. AU - Arumugam, S. AU - Filho, F. Souza T2 - American Geophysical Union Fall Meeting C2 - 2002/12/12/ CY - San Francisco, CA DA - 2002/12/12/ PY - 2002/12/12/ ER - TY - JOUR TI - Effectiveness of FRP for Strengthening Concrete Bridges AU - Rizkalla, Sami AU - Hassan, Tarek T2 - Structural Engineering International AB - This paper demonstrates an alternative use of FRP for strengthening concrete bridges in response to the demand towards increasing the flexural capacity to accommodate new truck loads. Several large-scale models of a prestressed concrete bridge were constructed and tested to failure to investigate the effectiveness of different FRP strengthening techniques. These techniques include near surface mounted bars and strips as well as externally bonded sheets and strips. Bond characteristics of near surface mounted FRP bars and strips are investigated by testing independently 17 concrete beams under monotonic static loading. Mathematical models for the interfacial shear stresses and the minimum anchorage length needed for near surface mounted bars and strips are presented. The feasibility of strengthening a prestressed concrete bridge using near surface mounting technique is discussed. The paper presents also an overview of the cost-effectiveness of each of the strengthening techniques considered in this study. DA - 2002/5// PY - 2002/5// DO - 10.2749/101686602777965577 VL - 12 IS - 2 SP - 89-95 J2 - Structural Engineering International LA - en OP - SN - 1016-8664 1683-0350 UR - http://dx.doi.org/10.2749/101686602777965577 DB - Crossref ER - TY - CHAP TI - Anaerobic Decomposition of Refuse in Landfills and Methane Oxidation in Landfill Cover Soils AU - Hilger, H.H. AU - Barlaz, M.A. T2 - Manual of Environmental Microbiology A2 - Hurst, Christon A2 - Crawford, Ronald PY - 2002/// ET - 2nd SP - 696 – 718 PB - American Society of Microbiology ER - TY - JOUR TI - Annual hydroclimatology of the United States AU - Sankarasubramanian, A. AU - Vogel, Richard M. T2 - Water Resources Research AB - An overview of the annual hydroclimatology of the United States is provided. Time series of monthly streamflow, temperature, and precipitation are developed for 1337 watersheds in the United States. This unique data set is then used to evaluate several approaches for estimating the long‐term water balance and the interannual variability of streamflow. Traditional relationships which predict either actual evapotranspiration or the interannual variability of streamflow from an aridity index are shown to perform poorly for basins with low soil moisture storage capacity. A water balance model is used to formulate new relationships for predicting actual evapotranspiration and the interannual variability of streamflow. These relationships depend on both the aridity index and a new soil moisture storage index. A physically based approach for estimating the soil moisture storage index is introduced which requires monthly time series of precipitation, potential evapotranspiration, and an estimate of maximum soil moisture holding capacity. The net results are improved expressions for the long‐term water balance and the interannual variability of streamflow which do not require either calibration or streamflow data. DA - 2002/6// PY - 2002/6// DO - 10.1029/2001wr000619 VL - 38 IS - 6 SN - 0043-1397 UR - http://dx.doi.org/10.1029/2001wr000619 KW - hydroclimatology KW - water balance KW - aridity KW - soil moisture KW - humidity KW - evapotranspiration ER - TY - JOUR TI - Comment on the paper: “Basin hydrologic response relations to distributed physiographic descriptors and climate” by Karen Plaut Berger, Dara Entekhabi, 2001. Journal of Hydrology 247, 169–182 AU - Sankarasubramanian, A. AU - Vogel, Richard M. T2 - Journal of Hydrology DA - 2002/6// PY - 2002/6// DO - 10.1016/s0022-1694(02)00061-6 VL - 263 IS - 1-4 SP - 257-261 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/s0022-1694(02)00061-6 DB - Crossref ER - TY - JOUR TI - Production planning for a project job shop, with application to disassembly, evaluation and maintenance of nuclear weapons AU - Nozick, Linda K. AU - Turnquist, Mark A. AU - Lawton, Craig R. AU - List, G. F. AU - Jones, Dean A. AU - Wright, Stephen T. AU - Kjeldgaard, Edwin A. T2 - Production Planning & Control AB - Production planning in some make-to-order operations bears considerable resemblance to resource-constrained project scheduling. This type of operation is referred to as a 'project job shop.' The practical problem that provides motivation for the methodology developed in this paper is such a production environment - the Department of Energy Pantex plant in Amarillo, Texas, where nuclear weapons are maintained and dismantled. In order to be useful in practice at Pantex, a production planning model must be able to handle a few hundred tasks (at least), with about 30 different types of facility resources, and 80-90 technicians who hold different combinations of 90-100 different certifications (qualifications to perform specific tasks). An approach has been developed to this production planning problem that is also transferable to project scheduling environments. The formulation uses continuous variables rather than the discrete variables commonly used in project scheduling formulations. This formulation allows time periods of variable lengths, and accepts arbitrary time boundaries (daily, weekly, monthly, etc.) within which resource availability is measured. The solution approach for this formulation is described, and two example problems are used to illustrate application of the model. DA - 2002/1// PY - 2002/1// DO - 10.1080/09537280110069766 VL - 13 IS - 2 SP - 187-198 J2 - Production Planning & Control LA - en OP - SN - 0953-7287 1366-5871 UR - http://dx.doi.org/10.1080/09537280110069766 DB - Crossref KW - production planning KW - resource-constrained project scheduling KW - project job shops KW - generalized benders' decomposition ER - TY - JOUR TI - In the (adsorption) competition between NOM and MIB, who is the winner, and why? AU - Newcombe, G. AU - Morrison, J. AU - Hepplewhite, C. AU - Knappe, D.R.U. T2 - Water Science and Technology: Water Supply AB - The adsorption of an odour compound common in drinking water, 2-methylisoborneol (MIB), was studied on four activated carbons in the presence of six 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 blockage, and or 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 - 2002/4// PY - 2002/4// DO - 10.2166/ws.2002.0046 VL - 2 IS - 2 SP - 59-67 LA - en OP - SN - 1606-9749 1607-0798 UR - http://dx.doi.org/10.2166/ws.2002.0046 DB - Crossref KW - activated carbon KW - adsorption KW - MIB KW - tastes and odours ER - TY - BOOK TI - Optimization of activated sludge designs using genetic algorithms DA - 2002/// PY - 2002/// VL - 45 SE - 187-198 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036219345&partnerID=MN8TOARS ER - TY - CONF TI - Characterization of drinking water treatment chemical mixing performance using CFD AU - Ducoste, J.J. AU - Ortiz, V. C2 - 2002/// C3 - Conference Proceedings - Joint 2002 CSCE/ASCE International Conference on Environmental Engineering - An International Perspective on Environmental Engineering DA - 2002/// SP - 427-443 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-23844485284&partnerID=MN8TOARS ER - TY - CHAP TI - Impact of the form of the momentum equation on shallow water models based on the generalized wave continuity equation AU - Dresback, KM AU - Kolar, RL AU - Dietrich, JC AU - Hassanizadeh, SM AU - Schotting, RJ AU - Gray, WG AU - Pinder, GF T2 - Computational Methods in Water Resources, Vols 1 and 2, Proceedings PY - 2002/// VL - 47 SP - 1573-1580 PB - SE - UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000178839400203&KeyUID=WOS:000178839400203 ER - TY - JOUR TI - Role of filamentous microorganisms in activated sludge foaming: relationship of mycolata levels to foaming initiation and stability. AU - Reyes, F. L. AU - Raskin, L. T2 - Water Res DA - 2002/// PY - 2002/// VL - 36 IS - 2 SP - 445-59 ER - TY - JOUR TI - Optimization of activated sludge designs using genetic algorithms AU - Doby, TA AU - Loughlin, DH AU - Reyes, FL AU - Ducoste, JJ T2 - Water Science and Technology DA - 2002/// PY - 2002/// VL - 45 IS - 6 SP - 187-198 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000175103800019&KeyUID=WOS:000175103800019 ER - TY - JOUR TI - Role of filamentous microorganisms in activated sludge foaming: relationship of mycolata levels to foaming initiation and stability AU - Reyes, FL AU - Raskin, L T2 - Water Research AB - The relationship between the levels of mycolic acid-containing actinomycetes (mycolata), Gordonia spp. and Gordonia amarae, and foam initiation and stability was characterized using: (1) batch tests involving addition of G. amarace cells to activated sludge, (2) analysis of a full-scale activated sludge plant that experienced seasonal foaming, and (3) a study of lab-scale activated sludge reactors augmented with G. amarae. Using batch tests, threshold Gordonia levels for foam formation and foam stability were determined to be approximately 2 x 10(8) microm ml(-1) and 1 x 10(9) microm ml(-1), respectively. In the full-scale plant, the levels of Gordonia spp. and G. amarae increased during the course of foaming, and the foam formation threshold of 2 x 10 microm ml(-1) corresponded to the onset of foaming. This value was also verified in lab-scale reactor washout experiments, where decreasing mycolata levels were observed during the course of foam dissipation. The foam stability threshold of 1 x 10(9) micorm ml(-1) was verified in lab-scale reactor studies. The increase in the levels of Gordonia spp. and G. amarae in the full-scale plant corresponded to an increase in temperature, suggesting that the growth of Gordonia spp. was favored during warmer periods. DA - 2002/1// PY - 2002/1// DO - 10.1016/s0043-1354(01)00227-5 VL - 36 IS - 2 SP - 445-459 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000173085900009&KeyUID=WOS:000173085900009 KW - activated sludge KW - filamentous foaming KW - nocardioforms KW - foam threshold KW - Gordonia amarae KW - 16S ribosomal RNA ER - TY - BOOK TI - Optimization of activated sludge designs using genetic algorithms DA - 2002/// PY - 2002/// VL - 45 SE - 187-198 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036219345&partnerID=MN8TOARS ER - TY - JOUR TI - Microbial community structures in foaming and nonfoaming full-scale wastewater treatment plants. T2 - Water environment research : a research publication of the Water Environment Federation DA - 2002/// PY - 2002/// VL - 74 IS - 5 SP - 437-449 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036730237&partnerID=MN8TOARS ER - TY - JOUR TI - Microbial community structures in foaming and nonfoaming full-scale wastewater treatment plants. AU - Reyes, F. L. AU - Rothauszky, D. AU - Raskin, L. T2 - Water Environ Res DA - 2002/// PY - 2002/// VL - 74 IS - 5 SP - 437-49 ER - TY - JOUR TI - MODELING THE COMPETITION BETWEEN FILAMENTS AND FLOC FORMERS: INTEGRATING DECAY RATE, STORAGE, KINETIC SELECTION, AND FILAMENTOUS BACKBONE THEORY AU - Lou, In Chio AU - Reyes, Francis L. T2 - proc water environ fed DA - 2002/1/1/ PY - 2002/1/1/ DO - 10.2175/193864702784248539 VL - 2002 IS - 17 SP - 47-58 ER - TY - JOUR TI - Detection and quantification of an environmentally versatile Bacillus strain using hybridization probes targeting the 16S rRNA and 16S-23S rRNA spacer region AU - Keith, J. E. AU - Leder, J. AU - Reyes, F. L., III T2 - Abstracts of the General Meeting of the American Society for Microbiology DA - 2002/// PY - 2002/// VL - 102 SP - 431 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=BCI&KeyUT=BCI:BCI200200616990&KeyUID=BCI:BCI200200616990 ER - TY - JOUR TI - Molecular Methods in Biological Systems AU - Oerther, Daniel B. AU - Reyes, Francis L. T2 - water environ res AB - Water Environment ResearchVolume 74, Issue 7 p. 71-105 Monitoring and MeasurementFree Access Molecular Methods in Biological Systems Daniel B. Oerther, Daniel B. OertherSearch for more papers by this authorFrancis L. de los Reyes III, Francis L. de los Reyes IIISearch for more papers by this author Daniel B. Oerther, Daniel B. OertherSearch for more papers by this authorFrancis L. de los Reyes III, Francis L. de los Reyes IIISearch for more papers by this author First published: 01 October 2002 https://doi.org/10.2175/106143002X140413AboutPDF 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 Volume74, Issue72002 Literature ReviewJuly-August 2002Pages 71-105 RelatedInformation DA - 2002/10/1/ PY - 2002/10/1/ DO - 10.2175/106143002x140413 VL - 74 IS - 6 SP - 71-105 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000208064900003&KeyUID=WOS:000208064900003 ER - TY - JOUR TI - Microbial Community Structures in Foaming and Nonfoaming Full-Scale Wastewater Treatment Plants AU - Reyes, Francis L. AU - Rothauszky, Dagmar AU - Raskin, Lutgarde T2 - water environ res AB - A survey of full‐scale activated‐sludge plants in Illinois revealed that filamentous foaming is a widespread problem in the state, and that the causes and consequences of foaming control strategies are not fully understood. To link microbial community structure to foam occurrence, microbial populations in eight foaming and nine nonfoaming full‐scale activated‐sludge systems were quantified using oligonucleotide hybridization probes targeting the ribosomal RNA (rRNA) of the mycolata; Gordonia spp.; Gordonia amarae ; “ Candidatus Microthrix parvicella”; the α‐, β‐, and γ‐subclasses of the Proteobacteria , and members of the Cytophaga‐Flavobacteria . Parallel measurements of microbial population abundance using hybridization of extracted RNA and fluorescence in situ hybridization (FISH) showed that the levels of mycolata, particularly Gordonia spp., were higher in most foaming systems compared with nonfoaming systems. Fluorescence in situ hybridization and microscopy suggested the involvement of “ Candidatus Microthrix parvicella” and Skermania piniformis in foam formation in other plants. Finally, high numbers of “ Candidatus Microthrix parvicella” were detected by FISH in foam and mixed liquor samples of one plant, whereas the corresponding levels of rRNA were low. This finding implies that inactive “ Candidatus Microthrix parvicella” cells (i.e., cells with low rRNA levels) can cause foaming. DA - 2002/9/1/ PY - 2002/9/1/ DO - 10.2175/106143002x140233 VL - 74 IS - 5 SP - 437-449 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000179440400004&KeyUID=WOS:000179440400004 KW - activated sludge KW - filamentous foaming KW - microbial community structure KW - oligonucleotide probes ER - TY - CONF TI - Effect of flow-modifiers on permeation behavior of fly ash with a nonwoven geotextile AU - Akram, M. A. AU - Gabr, M. A. C2 - 2002/// C3 - 37th Engineering Geology and Geotechnical Engineering Symposium, Soil Properties, Boise, Idaho, March 2002 DA - 2002/// PB - Pocatello, Idaho : College of Engineering, Idaho State University ER - TY - RPRT TI - Sign count approximation using field inventory sampling and calculated sign densities: Analysis, improvements, and methods A3 - Raleigh, N.C.: Department of Civil Engineering, North Carolina State University DA - 2002/// PY - 2002/// PB - Raleigh, N.C.: Department of Civil Engineering, North Carolina State University ER - TY - RPRT TI - An interoperable information system design for traffic survey data AU - Rasdorf, W. AU - Taylor, K. AU - Wikoff, L. AU - Robson, F. AU - Jerman, D. AU - Smith, L. C. A3 - Raleigh, N.C.: North Carolina Department of Transportation DA - 2002/// PY - 2002/// PB - Raleigh, N.C.: North Carolina Department of Transportation ER - TY - RPRT TI - A sign inventory study to assess and control liability and cost AU - Vereen, S. AU - Hummer, J. E. AU - Rasdorf, W. A3 - Raleigh, N.C.: North Carolina Department of Transportation C6 - FHWA/NC 2002-16 DA - 2002/// PY - 2002/// PB - Raleigh, N.C.: North Carolina Department of Transportation ER - TY - CONF TI - Influence of wear mechanisms on geosynthetic interface strengths AU - Frost, J. D. AU - Evans, T. M. AU - Hebeler, G. L. AU - Giroud, J. P. A2 - Ph. Delmas, A2 - Gourc, J. P. C2 - 2002/// C3 - Geosynthetics : state of the art, recent developments : proceedings of the seventh International Conference on Geosynthetics, 7 ICG-Nice 2002, France, 22-27 September 2002 DA - 2002/// SP - 1325-1328 PB - Lisse: Balkema SN - 9058095231 ER - TY - PAT TI - Crane monitoring and data retrieval systems and AU - Bernold, L. E. AU - Lorenc, S. J. AU - Elliott, S. D. AU - Cobb, M. S. AU - Green, A. R. C2 - 2002/// DA - 2002/// PY - 2002/// ER - TY - JOUR TI - Spatial integration in construction AU - Bernold, L. E. T2 - Journal of Construction Engineering and Management AB - Work in construction always requires moving within, and interacting with, a complex environment while handling heavy materials and building elements to be joined, inserted, or aligned. Modern design software is able to digitally model all of those elements in their spatially correct configuration, and without interference. When it comes to the actual construction, however, the spatial models do not find any use. Twenty years after the manufacturing industry began using electronic design data to control their machinery, construction is also getting ready to move away from its longstanding tradition of working with paper-based blueprints. The newest steps on the path toward the use of three-dimensional digital design data in support of site operation are stimulated by the global positioning system and the many uses of lasers. Surveying has always performed critical functions on construction sites, such as marking building layouts, anchor bolts, concrete formwork, or bridge bearings. The objective of spatial integration in construction is to digitally merge spatial design data with the digital model of equipment working on implementing the design. This paper will briefly review historical advancements in “perfecting” the surveying technology before presenting three examples of a quantum leap in the way we design, plan, and control construction projects in the future. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)0733-9364(2002)128:5(400) VL - 128 IS - 5 SP - 400-408 ER - TY - JOUR TI - Probabilistic analysis of driving cycle-based highway vehicle emission factors AU - Frey, HC AU - Zheng, JY T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - A probabilistic methodology for quantifying intervehicle variability and fleet average uncertainty in highway vehicle emission factors is developed. The methodology features the use of empirical distributions of emissions measurement data to characterize variability and the use of bootstrap simulation to characterize uncertainty. For the base emission rate as a function of mileage accumulation under standard conditions, a regression-based approach was employed in which the residual error terms were included in the probabilistic analysis. Probabilistic correction factors for different driving cycles, ambient temperature, and fuel Reid vapor pressure (RVP) were developed without interpolation or extrapolation of available data. The method was demonstrated for tailpipe carbon monoxide, hydrocarbon, and nitrogen oxides emissions for a selected light-duty gasoline vehicle technology. Intervehicle variability in emissions was found to span typically 2 or 3 orders of magnitude. The uncertainty in the fleet average emission factor was as low as +/- 10% for a 95% probability range, in the case of standard conditions, to as much as -90% to +280% when correction factors for alternative driving cycles, temperature, and RVP are applied. The implications of the results for method selection and for decision making are addressed. DA - 2002/12/1/ PY - 2002/12/1/ DO - 10.1021/es0114308 VL - 36 IS - 23 SP - 5184-5191 SN - 0013-936X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036882670&partnerID=MN8TOARS ER - TY - JOUR TI - Life-cycle-based solid waste management. I: Model development AU - Solano, E. AU - Ranjithan, S. R. AU - Barlaz, Morton AU - Brill, E. D. T2 - Journal of Environmental Engineering (New York, N.Y.) AB - This paper describes an integrated solid waste management (ISWM) model to assist in identifying alternative SWM strategies that meet cost, energy, and environmental emissions objectives. An SWM system consisting of over 40 unit processes for collection, transfer, separation, treatment (e.g., combustion, composting), and disposal of waste as well as remanufacturing facilities for processing recycled material is defined. Waste is categorized into 48 items and their generation rates are defined for three types of sectors: single-family dwelling, multifamily dwelling, and commercial. The mass flow of each item through all possible combinations of unit processes is represented in a linear programming model using a unique modeling approach. Cost, energy consumption, and environmental emissions associated with waste processing at each unit process are computed in a set of specially implemented unit process models. A life-cycle approach is used to compute energy consumption and emissions of CO, fossil- and biomass-derived CO2,NOx,SOx, particulate matter, PM10 and greenhouse gases. The model is flexible to allow representation of site-specific issues, including waste diversion targets, mass flow restrictions and requirements, and targets for the values of cost, energy, and each emission. A companion paper describes the application of this model to examine several SWM scenarios for a hypothetical, but realistic, case study. DA - 2002/// PY - 2002/// DO - 10.1061/(asce)0733-9372(2002)128:10(981) VL - 128 IS - 10 SP - 981–992 ER - TY - JOUR TI - Life-Cycle-based Solid Waste Management. II: Illustrative Applications AU - Solano, Eric AU - Dumas, Robert D. AU - Harrison, Kenneth W. AU - Ranjithan, S. Ranji AU - Barlaz, Morton A. AU - Downey Brill, E. T2 - Journal of Environmental Engineering AB - A companion paper described the development of the integrated solid waste management (ISWM) model that considers cost, energy, and environmental releases associated with management of municipal solid waste. This paper demonstrates the application of the ISWM model to a hypothetical, but realistic, case study. Several solid waste management (SWM) scenarios are studied, including the variation in energy and environmental emissions among alternate SWM strategies; the effect of mandated waste diversion (through recycling and other beneficial uses of waste such as combustion to recover energy) on environmental releases and cost; the tradeoff between cost and the level of waste diversion; and the tradeoff between cost and greenhouse gas emissions. In addition, the flexibility of the model is illustrated by the identification of alternate SWM strategies that meet approximately the same objectives using distinctly different combinations of unit processes. This flexibility may be of importance to local solid waste management planners who must implement new SWM programs. Use of the model illustrates the potential impact of solid waste management policies and regulations on global environmental emissions. DA - 2002/10// PY - 2002/10// DO - 10.1061/(asce)0733-9372(2002)128:10(993) VL - 128 IS - 10 SP - 993-1005 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(asce)0733-9372(2002)128:10(993) DB - Crossref ER - TY - JOUR TI - Quantification of variability and uncertainty in air pollutant emission inventories: Method and case study for utility NOx emissions AU - Frey, HC AU - Zheng, JY T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - The quality of stationary source emission factors is typically described using data quality ratings, which provide no quantification of the precision of the emission factor for an average source, nor of the variability from one source to another within a category. Variability refers to actual differences caused by differences in feedstock composition, design, maintenance, and operation. Uncertainty refers to lack of knowledge regarding the true emissions. A general methodology for the quantification of variability and uncertainty in emission factors, activity factors, and emission inventories (EIs) is described, featuring the use of bootstrap simulation and related techniques. The methodology is demonstrated via a case study for a selected example of NOx emissions from coal-fired power plants. A prototype software tool was developed to implement the methodology. The range of interunit variability in selected activity and emission factors was shown to be as much as a factor of 4, and the range of uncertainty in mean emissions is shown to depend on the interunit variability and sample size. The uncertainty in the total inventory of -16 to +19% was attributed primarily to one technology group, suggesting priorities for collecting data and improving the inventory. The implications for decision-making are discussed. DA - 2002/9// PY - 2002/9// DO - 10.1080/10473289.2002.10470837 VL - 52 IS - 9 SP - 1083-1095 SN - 1047-3289 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036715372&partnerID=MN8TOARS ER - TY - CHAP TI - Characteristics of geogrid-reinforced aggregate under cyclic load AU - Leng, J. J. AU - Gabr, M. A. T2 - Geology and properties of earth materials, 2002 AB - The characteristics of geogrid-reinforced aggregates over soft subgrade soil were investigated through a laboratory-testing program. Nine cyclic plate load tests were conducted with varying base layer thickness and reinforcement type. Results indicated that aggregate base course (ABC) degraded under cyclic loading as manifested by an increase in stresses at the interface between the ABC and the subgrade with increasing number of cycles. The improvement in stress distribution due to geosynthetic inclusion at the interface of ABC and subgrade soil is indicated by a decrease in the measured maximum stress (under the center of the loaded area) and the measurement of a more uniform stress distribution on the subgrade soil layer. The higher modulus geogrid provided a better load-spreading effect compared with a lower modulus geogrid used in the testing. The improvement in plastic surface deformation was related to two aspects: ( a) decrease in vertical deformation of the subgrade and ( b) decrease in lateral spread of the ABC. A model that incorporates the mechanics of reinforcement contributions to deformation and stresses and the effect of ABC degradation as a function of number of load cycles needs to be developed for the transportation community to fully realize the benefits of reinforcement in such an application. PY - 2002/// DO - 10.3141/1786-04 VL - 1786 SP - 29–35 PB - Washington, DC: National Academy Press SN - 0309077117 ER - TY - CHAP TI - Temperature correction of multiload-level failing weight deflectometer deflections AU - Park, H. M. AU - Kim, Y. R. AU - Park, S. T2 - Assessing and evaluating pavements, 2002 AB - A new temperature correction procedure was developed for multiload-level falling weight deflectometer (FWD) deflections for flexible pavements in North Carolina. In this procedure, temperature correction factors were dependent on the radial offset distance from the FWD load plate. Temperature and FWD multiload-level deflection data used in developing this procedure were collected from 11 pavements in three different climatic regions of North Carolina. The effect of the FWD load level on this temperature correction procedure was investigated. Research efforts focused on improving the accuracy of the current temperature correction procedure of the North Carolina Department of Transportation. The measured deflection and temperature data were also used to validate the long-term pavement performance (LTPP) temperature correction procedure. It was found that the effective pavement temperature prediction algorithm in the LTPP procedure is relatively accurate and that the temperature-deflection correction procedure undercorrects the deflections at higher temperatures in pavements with an asphalt concrete layer thicker than 242 mm. The main reason for this deficiency is that the LTPP procedure was developed from the national database and cannot fully consider the local variation in mixture characteristics. CN - TE7 .H5 NO. 1806 PY - 2002/// DO - 10.3141/1806-01 SP - 3-8 PB - Washington, D.C.: National Academy Press SN - 030907732X ER - TY - JOUR TI - Hydraulic geometry relationships for urban streams throughout the piedmont of North Carolina AU - Doll, BA AU - Wise-Frederick, DE AU - Buckner, CM AU - Wilkerson, SD AU - Harman, WA AU - Smith, RE AU - Spooner, J T2 - JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION AB - ABSTRACT: Hydraulic geometry relationships, or regional curves, relate bankfull stream channel dimensions to watershed drainage area. Hydraulic geometry relationships for streams throughout North Carolina vary with hydrology, soils, and extent of development within a watershed. An urban curve that is the focus of this study shows the bankfull features of streams in urban and suburban watersheds throughout the North Carolina Piedmont. Seventeen streams were surveyed in watersheds that had greater than 10 percent impervious cover. The watersheds had been developed long enough for the streams to redevelop bankfull features, and they had no major impoundments. The drainage areas for the streams ranged from 0.4 to 110.3 square kilometers. Cross‐sectional and longitudinal surveys were conducted to determine the channel dimension, pattern, and profile of each stream and power functions were fitted to the data. Comparisons were made with regional curves developed previously for the rural Piedmont, and enlargement ratios were produced. These enlargement ratios indicated a substantial increase in the hydraulic geometry for the urban streams in comparison to the rural streams. A comparison of flood frequency indicates a slight decrease in the bankfull discharge return interval for the gaged urban streams as compared to the gaged rural streams. The study data were collected by North Carolina State University (NCSU), the University of North Carolina at Charlotte (UNC), and Charlotte Storm Water Services. Urban regional curves are useful tools for applying natural channel design in developed watersheds. They do not, however, replace the need for field calibration and verification of bankfull stream channel dimensions. DA - 2002/6// PY - 2002/6// DO - 10.1111/j.1752-1688.2002.tb00986.x VL - 38 IS - 3 SP - 641-651 SN - 1752-1688 UR - http://dx.doi.org/10.1111/j.1752-1688.2002.tb00986.x KW - hydraulic geometry KW - regional curve KW - bankfull KW - flood frequency analyses KW - urbanization KW - urban water management ER - TY - JOUR TI - Anaerobic biodegradation of aliphatic polyesters: Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) and poly(epsilon-caprolactone) AU - Federle, TW AU - Barlaz, MA AU - Pettigrew, CA AU - Kerr, KM AU - Kemper, JJ AU - Nuck, BA AU - Schechtman, LA T2 - BIOMACROMOLECULES AB - Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), PHBO, represents a class of PHA copolymers that contain both short-chain-length and medium-chain-length repeat units. Radiolabeled and cold PHBO, containing 90 mol % 3-hydroxybutyrate and 10 mol % 3-hydroxyoctanoate were chemically synthesized using a new difunctional alkoxyzinc initiator. (14)C-PHBO was incubated with samples of anaerobic digester sludge, septage, freshwater sediment, and marine sediment under conditions resembling those in situ. In addition, it was incubated in laboratory-scale landfill reactors. (14)C-PCL (poly-epsilon-caprolactone) was incubated with anaerobic digester sludge and in landfill reactors. Biodegradation was determined by measuring generation of (14)CO(2) and (14)CH(4) resulting from mineralization of the radiolabeled polymers. PHBO was extensively mineralized in digester sludge, septage sediments, and the landfill reactors, with half-lives less than 30 days. PCL was not significantly mineralized in digester sludge over 122 days. In the landfill reactors, PCL mineralization was slow and was preceded by a long lag period (>200 days), suggesting that PCL mineralization is limited by its rate of hydrolysis. The results indicate that PHBO is practically biodegradable in the major anaerobic habitats that it may enter. In contrast, anaerobic biodegradation of PCL is less ubiquitous and much slower. DA - 2002/// PY - 2002/// DO - 10.1021/bm025520w VL - 3 IS - 4 SP - 813-822 SN - 1526-4602 ER - TY - JOUR TI - A two-scale PBM for modeling turbulent flocculation in water treatment processes AU - Ducoste, J T2 - CHEMICAL ENGINEERING SCIENCE AB - A population balance model (PBM) that incorporates two scales of turbulent motion in the breakup frequency function has been presented. The breakup frequency function is designed such that particles smaller than the impeller-region Kolmogoroff microscale will erode according to a critical velocity related to the local energy dissipation rate. Particles larger than the impeller-region Kolmogoroff microscale will fracture according to a critical velocity related to the impeller tip speed. The two-scale model was found to better predict the experimental steady-state particle size distribution in 5, 28, and 560l tank sizes and with a Rushton turbine and A310 fluid foil impellers. The two-scale PBM was also used to investigate the most appropriate scale-up law for drinking water flocculation processes. In addition, the impact of higher tank average energy dissipation rate, primary particle concentration, and coagulant concentration on the volume mean particle size with increasing tank size and different impeller types was also presented. DA - 2002/6// PY - 2002/6// DO - 10.1016/S0009-2509(02)00108-2 VL - 57 IS - 12 SP - 2157-2168 SN - 0009-2509 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0037189454&partnerID=MN8TOARS KW - locculation KW - environment KW - population balance KW - modeling KW - scale-up ER - TY - JOUR TI - Special structures: Past, present, and future AU - Bradshaw, R. AU - Campbell, D. AU - Gargari, M. AU - Mirmiran, A. AU - Tripeny, P. T2 - Journal of Structural Engineering (New York, N.Y.) DA - 2002/// PY - 2002/// VL - 128 IS - 6 SP - 691-709 ER - TY - CHAP TI - New relationships between failing weight deflectometer deflections and asphalt pavement layer condition indicators AU - Xu, B. AU - Ranjithan, S. R. AU - Kim, Y. R. T2 - Assessing and evaluating pavements, 2002 AB - New relationships have been identified between the layer condition indicators of flexible pavements and falling weight deflectometer (FWD) deflections. Synthetic databases were generated using dynamic finite element analysis with nonlinear material models. The sensitivity of various deflection basin parameters (DBPs) to layer conditions was comprehensively examined on the basis of the developed databases. Three types of layer condition indicators were identified in the study, including DBPs, effective layer moduli, and stresses and strains. The DBPs identified from the sensitivity study were used in developing new relationships between the selected condition indicators and FWD deflections by applying regression and artificial neural network techniques. Even though these relationships include the complicated dynamic effect of FWD loading and nonlinear behavior of unbound materials, the time to obtain results from these procedures is insignificant, thus making the procedures suitable for field implementation. CN - TE7 .H5 NO. 1806 PY - 2002/// DO - 10.3141/1806-06 SP - 48-56 PB - Washington, D.C.: National Academy Press SN - 030907732X ER - TY - CHAP TI - New condition assessment procedure for asphalt pavement layers using failing weight deflectometer deflections AU - Xu, B. AU - Ranjithan, S. R. AU - Kim, Y. R. T2 - Assessing and evaluating pavements, 2002 AB - Nondestructive condition assessment criteria were developed for application in conjunction with the condition evaluation indicators that are estimated based on falling weight deflectometer (FWD) deflections. Data obtained from state departments of transportation and DATAPAVE 2.0 were used in developing these criteria. To account for the effects of pavement structure and temperature on FWD deflection analysis, structure and temperature correction procedures based on synthetic databases were applied. Also, a deflection prescreening procedure was established to identify and correct any irregular deflection basins potentially arising from measurement errors. All the calibrated predictive procedures, structure and temperature correction procedures, and prescreening algorithms were incorporated into the user-friendly deflection analysis program with graphical interface, Asphalt Pavement Layer Condition Assessment Program, or APLCAP. CN - TE7 .H5 NO. 1806 PY - 2002/// DO - 10.3141/1806-07 SP - 57-69 PB - Washington, D.C.: National Academy Press SN - 030907732X ER - TY - JOUR TI - In-plane testing of damaged masonry wall repaired with FRP AU - Fam, A. AU - Musiker, D. AU - Kowalsky, M. AU - Rizkalla, S. T2 - Advanced Composites Letters AB - This paper describes the performance of a masonry wall repaired with glass fibre reinforced polymer, GFRP sheets. The original reinforced clay brick masonry wall was tested under in-plane lateral cyclic loading. Failure occurred due to yielding of the steel reinforcement and crushing of the bricks. After epoxy injection of the cracks and patching of the missing portions, the wall was repaired using GFRP sheets, applied in the horizontal and vertical directions, on one face of the wall, including the joint between the wall and concrete footing. The repaired wall was tested to failure in the same manner of the original wall. The results show that the strength and displacement capacities of the wall were completely restored and even exceeded the original capacities. DA - 2002/// PY - 2002/// DO - 10.1177/096369350201100602 VL - 11 IS - 6 SP - 277-283 ER - TY - JOUR TI - Flexural strengthening of prestressed bridge slabs with FRP systems AU - Hassan, T AU - Rizkalla, S T2 - PCI JOURNAL AB - Fiber reinforced polymer (FRP) materials offer great potential for cost effective retrofitting of concrete structures. In response for the growing need for strengthening and rehabilitation of concrete structures and bridges, an experimental program was conducted to investigate the feasibility of using different strengthening techniques as well as different types of FRP for strengthening prestressed concrete members. Half scale models of a prestressed concrete bridge were constructed and tested to failure. The test specimens consisted of one simple span and two overhanging cantilevers. Each specimen was tested three times using a different load location in each case. The applicability of a nonlinear finite element analysis of post-tensioned bridge slabs strengthened with near surface mounted FRP reinforcement is enumerated. DA - 2002/// PY - 2002/// DO - 10.15554/pcij.01012002.76.93 VL - 47 IS - 1 SP - 76-93 SN - 0887-9672 ER - TY - JOUR TI - An advancement in cyclic plasticity modeling for multiaxial ratcheting simulation AU - Bari, S AU - Hassan, T T2 - INTERNATIONAL JOURNAL OF PLASTICITY AB - In a search for a constitutive model for ratcheting simulations, the models by Chaboche, Ohno–Wang, McDowell, Jiang–Sehitoglu, Voyiadjis–Basuroychowdhury and AbdelKarim–Ohno are evaluated against a set of uniaxial and biaxial ratcheting responses. With the assumption of invariant shape of the yield surface during plastic loading, the ratcheting simulations for uniaxial loading are primarily a function of the plastic modulus calculation, whereas the simulations for multiaxial loading are sensitive to the kinematic hardening rule of a model. This characteristic of the above mentioned models is elaborated in this paper. It is demonstrated that if all parameters of the kinematic hardening rule are determined from uniaxial responses only, these parameters primarily enable a better plastic modulus calculation. However, in this case the role of the kinematic hardening rule in representing the ratcheting responses for multiaxial loading is under-appreciated. This realization motivated many researchers to incorporate multiaxial load dependent terms or parameters into the kinematic hardening rule. This paper evaluates some of these modified rules and finds that none is general enough to simulate the ratcheting responses consistently for the experiments considered. A modified kinematic hardening rule is proposed using the idea of Delobelle and his co-workers in the framework of the Chaboche model. This new rule introduces only one multiaxial load dependent parameter to the Chaboche model, but performs the best in simulating all the ratcheting responses considered. DA - 2002/// PY - 2002/// DO - 10.1016/S0749-6419(01)00012-2 VL - 18 IS - 7 SP - 873-894 SN - 0749-6419 KW - cyclic plasticity KW - multiaxial ratcheting KW - constitutive modeling ER - TY - JOUR TI - Toward a micromechanics-based procedure to characterize fatigue performance of asphalt concrete AU - Guddati, MN AU - Feng, Z AU - Kim, YR T2 - BITUMINOUS PAVING MIXTURES 2002 AB - A lattice-based micromechanics approach is proposed to characterize the cracking performance of asphalt concrete. A random truss lattice model was introduced and investigated for simulating the following: ( a) linear elastic and viscoelastic deformation of homogeneous materials in axial compression and shear loading experiments, ( b) linear elastic deformation and the stress field in heterogeneous materials in an axial compression loading experiment, and ( c) damage evolution in elastic solids under an indirect tensile test. The simulation results match well with the theoretical solutions and show excellent promise in predicting cracking patterns in the indirect tensile test. A brief discussion about ongoing work is also presented. DA - 2002/// PY - 2002/// DO - 10.3141/1789-13 IS - 1789 SP - 121-128 SN - 0361-1981 ER - TY - JOUR TI - Simple performance test for fatigue cracking and validation with WesTrack mixtures AU - Wen, HF AU - Kim, YR T2 - BITUMINOUS PAVING MIXTURES 2002 AB - Viscoelastic characterization of asphalt concrete in indirect tensile (IDT) testing and development of a simple performance test for fatigue cracking are described. A 50-mm gauge length was adopted to measure the horizontal and vertical deformations with surface-mounted linear variable differential transducers on an IDT specimen with a 100- or 150-mm diameter and 38-mm thickness. The effect of a concentrated load under loading strips on vertical displacement within the 50-mm gauge length was evaluated by the digital image correlation method, a noncontact, full-field displacement and strain measurement technique. The theory of viscoelasticity was used to develop analytical solutions for creep compliance and center strain from displacements measured on the specimen surface. These solutions were verified by three-dimensional finite element viscoelastic analysis. IDT creep and strength tests were performed on fine and coarse mixtures from WesTrack with various asphalt contents and air void contents, and various parameters determined from the analysis of these data were compared with the known fatigue performance of these mixtures from the WesTrack testing facility. The fracture energy obtained from viscoelastic analysis of the IDT strength test at 20°C correlated highly with the field performance of these mixtures at WesTrack. DA - 2002/// PY - 2002/// DO - 10.3141/1789-07 IS - 1789 SP - 66-72 SN - 0361-1981 ER - TY - JOUR TI - Present and long-term composition of MSW landfill leachate: A review AU - Kjeldsen, P AU - Barlaz, MA AU - Rooker, AP AU - Baun, A AU - Ledin, A AU - Christensen, TH T2 - CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY AB - The major potential environmental impacts related to landfill leachate are pollution of groundwater and surface waters. Landfill leachate contains pollutants that can be categorized into four groups (dissolved organic matter, inorganic macrocomponents, heavy metals, and xenobiotic organic compounds). Existing data show high leachate concentrations of all components in the early acid phase due to strong decomposition and leaching. In the long methanogenic phase a more stable leachate, with lower concentrations and a low BOD/COD-ratio, is observed. Generally, very low concentrations of heavy metals are observed. In contrast, the concentration of ammonia does not decrease, and often constitutes a major long-term pollutant in leachate. A broad range of xenobiotic organic compounds is observed in landfill leachate. The long-term behavior of landfills with respect to changes in oxidation-reduction status is discussed based on theory and model simulations. It seems that the somewhere postulated enhanced release of accumulated heavy metals would not take place within the time frames of thousands of years. This is supported by a few laboratory investigations. The existing data and model evaluations indicate that the xenobiotic organic compounds in most cases do not constitute a major long-term problem. This may suggest that ammonia will be of most concern in the long run. DA - 2002/// PY - 2002/// DO - 10.1080/10643380290813462 VL - 32 IS - 4 SP - 297-336 SN - 1547-6537 KW - waste disposal KW - xenobiotic organic compound KW - ammonia KW - dissolved organic matter KW - heavy metals KW - toxicological testing ER - TY - JOUR TI - Numerical Analysis of Geosynthetic-Reinforced and Pile-Supported Earth Platforms over Soft Soil AU - Han, J. AU - Gabr, M. A. T2 - Journal of Geotechnical and Geoenvironmental Engineering AB - Geotechnical engineers face several challenges when designing structures over soft soils. These include potential bearing failure, intolerable settlement, large lateral pressures and movement, and global or local instability. Geosynthetic-reinforced and pile-supported earth platforms provide an economic and effective solution for embankments, retaining walls, and storage tanks, etc. constructed on soft soils; especially when rapid construction and/or strict deformation of the structure are required. The inclusion of geosynthetic(s) in the fill enhances the efficiency of load transfer, minimizes yielding of the soil above the pile head, and potentially reduces total and differential settlements. A numerical study has been conducted to investigate pile-soil-geosynthetic(s) interactions by considering three major influence factors: the height of the fill, the tensile stiffness of geosynthetic, and the elastic modulus of pile material. While current methods have not fully addressed important effects of the geosynthetic stiffness and pile modulus on the soil arching ratio, numerical results suggested that the stress concentration ratio and the maximum tension in geosynthetic increase with the height of the embankment fill, the tensile stiffness of geosynthetic, and the elastic modulus of the pile material. The distribution of tension force in the geosynthetic reinforcement indicated that the maximum tension occurs near the edge of the pile. DA - 2002/1// PY - 2002/1// DO - 10.1061/(ASCE)1090-0241(2002)128:1(44) VL - 128 IS - 1 SP - 44-53 ER - TY - JOUR TI - Modeling of disinfection contactor hydraulics under uncertainty AU - Peplinski, D. K. AU - Ducoste, J. T2 - Journal of Environmental Engineering (New York, N.Y.) AB - A study has been done to evaluate the predictive capabilities of computational fluid dynamics (CFD) models of disinfection contactor hydraulics under model input uncertainty. The study consists of modeling the transport of a chemical tracer in a full-scale reactor and predicting the effluent residence time distribution (RTD) curve. An uncertainty analysis using Monte Carlo probabilistic techniques was used to determine the sensitivity of the effluent RTD to uncertainty in the influent turbulent kinetic energy constant, the turbulent Schmidt number, the wall roughness height, the influent turbulent length scale, and the turbulence model selection. Kruskal–Wallis, Friedman, and Spearman Rho statistical tests were used to evaluate changes in T10/HRT and Morril index due to input uncertainties. The results show that there are some variations in the effluent RTD due to changes in the model input parameters. The effluent RTD variations increased with decreasing contactor hydraulic efficiency or increased mixing. The effluent RTD was most sensitive to uncertainty in the turbulent Schmidt number and the selected turbulence model. DA - 2002/// PY - 2002/// DO - 10.1061/(asce)0733-9372(2002)128:11(1056) VL - 128 IS - 11 SP - 1056–1067 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036849140&partnerID=MN8TOARS ER - TY - JOUR TI - Flexural creep tests and modeling of concrete-filled fiber reinforced polymer tubes AU - Naguib, W. AU - Mirmiran, A. T2 - Journal of Composites for Construction AB - An experimental and analytical investigation was made into the flexural creep behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFT). While creep effects reduce the flexural stiffness of CFFT specimens, ultimate strength is not significantly altered. The slow rate of loading and short-term creep at 70% of static capacity may cause premature rupture of the tube. Fiber analysis of CFFT beam-columns by discretizing the section into filled and hollow FRP tubes can adequately simulate the flexural creep behavior. Isochronous sustained stress-creep strain curves are used as a constitutive nonlinear relationship for creep analysis in flexure. Creep deflection of CFFT beam-columns is much less than that of CFFT beams, mainly because axial compressive loads tend to retard the cracking of concrete and tensile creep of FRP. The stiffness ratio of FRP tubes with respect to the concrete core has a pronounced effect on the creep deflection of CFFT beam-columns. As the stiffness ratio increases, creep deflection decreases. However, there exists a threshold beyond which stiffer tubes do not provide additional benefit. CFFT beam-columns under high levels of sustained axial loads have a lower creep rupture life expectancy, mainly because failure moments under large axial forces are lower. The creep rupture life expectancy of CFFT beam-columns with diameter-to-thickness ratios of 40 or less is at least 50 years at transverse loads as high as 60% of the static capacity. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)1090-0268(2002)6:4(272) VL - 6 IS - 4 SP - 272-279 ER - TY - JOUR TI - Effect of hydrogen on adsorbed precursor diffusion kinetics during hydrogenated amorphous silicon deposition AU - Bray, K. R. AU - Gupta, A. AU - Parsons, G. N. T2 - Applied Physics Letters AB - Fractal analysis of the surface topography is used to study the effects of hydrogen dilution on the surface transport kinetics during the plasma deposition of hydrogenated amorphous silicon. Images obtained from atomic force microscopy are examined using dimensional fractal analysis, and surface diffusion lengths of growth precursors are estimated from the measured correlation lengths. The addition of small amounts of hydrogen (H2/SiH4 ratios &lt;10/1) during deposition leads to a decrease in the diffusion length, but larger hydrogen dilutions result in increased diffusion length. Moreover, the measured surface diffusion activation barrier is reduced from 0.20 eV for deposition from pure SiH4 to 0.13 eV with high hydrogen dilution. Results are consistent with recent models for precursor surface transport during low-temperature deposition, and give insight into critical processes for low-temperature silicon crystallization. DA - 2002/// PY - 2002/// DO - 10.1063/1.1467616 VL - 80 IS - 13 SP - 2356-2358 ER - TY - JOUR TI - Application of digital image correlation method to mechanical testing of asphalt-aggregate mixtures AU - Seo, Y AU - Kim, YR AU - Witczak, MW AU - Bonaquist, R T2 - BITUMINOUS PAVING MIXTURES 2002 AB - The digital image correlation (DIC) method, a noncontact, full-field displacement measurement technique, has been applied to mechanical testing of asphalt concrete. A single couple charged device camera acquires images of an area of interest from a specimen in the undeformed and deformed states. These images are correlated to determine deformations, and advanced mathematical procedures are applied to these deformations to calculate strains. To verify the DIC measurements, vertical displacements for the middle and bottom sections of a specimen subjected to monotonic tension are compared with conventional linear variable differential transformer measurements. A series of DIC images captured during the monotonic and cyclic tests visualizes the evolution of the failure zone (i.e., the fracture process zone) at the crack tip. Also, it is demonstrated that the full-field measurement and post-processing nature of DIC allows a more accurate determination of the stress-strain behavior of the fracture process zone. The applicability of this method to a cylindrical specimen with a curved surface is also investigated by testing a 75-mm-diameter cylindrical specimen. Finally, the DIC method is extended to cyclic testing of asphalt mixtures with the aid of a synchronized image acquisition technique. DA - 2002/// PY - 2002/// DO - 10.3141/1789-18 IS - 1789 SP - 162-172 SN - 0361-1981 ER - TY - JOUR TI - A hybrid MPI-OpenMP implementation of an implicit finite-element code on parallel architectures AU - Mahinthakumar, G AU - Saied, F T2 - INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS AB - Summary The hybrid MPI-OpenMP model is a natural parallel programming paradigm for emerging parallel architectures that are based on symmetric multiprocessor (SMP) clusters. This paper presents a hybrid implementation adapted for an implicit finite-element code developed for groundwater transport simulations. The original code was parallelized for distributed memory architectures using MPI (Message Passing Interface) using a domain decomposition strategy. OpenMP directives were then added to the code (a straightforward loop-level implementation) to use multiple threads within each MPI process. To improve the OpenMP performance, several loop modifications were adopted. The parallel performance results are compared for four modern parallel architectures. The results show that for most of the cases tested, the pure MPI approach outperforms the hybrid model. The exceptions to this observation were mainly due to a limitation in the MPI library implementation on one of the architectures. A general conclusion is that while the hybrid model is a promising approach for SMP cluster architectures, at the time of this writing, the payoff may not be justified for converting all existing MPI codes to hybrid codes. However, improvements in OpenMP compilers combined with potential MPI limitations in SMP nodes may make the hybrid approach more attractive for a broader set of applications in the future. DA - 2002/// PY - 2002/// DO - 10.1177/109434200201600402 VL - 16 IS - 4 SP - 371-393 SN - 1094-3420 ER - TY - JOUR TI - Simultaneous adsorption of MIB and NOM onto activated carbon - II. Competitive effects AU - Newcombe, G AU - Morrison, J AU - Hepplewhite, C AU - Knappe, DRU T2 - CARBON AB - The adsorption of an odour compound common in drinking water, 2-methylisoborneol (MIB), was studied on six activated carbons in the presence of six 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 direct competition with MIB for adsorption sites. Equivalent background compound calculations indicated a relatively low concentration of directly competing compounds in the NOM. Some evidence of pore blockage and/or restriction was also seen, with microporous carbons being the most affected by low-molecular-weight NOM and mesoporous carbons impacted by the higher-molecular-weight compounds. DA - 2002/// PY - 2002/// DO - 10.1016/S0008-6223(02)00098-2 VL - 40 IS - 12 SP - 2147-2156 SN - 0008-6223 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036047185&partnerID=MN8TOARS KW - activated carbon KW - adsorption properties KW - surface properties ER - TY - JOUR TI - Pesticide adsorption by granular activated carbon adsorbers. 2. Effects of pesticide and natural organic matter characteristics on pesticide breakthrough curves AU - Matsui, Y AU - Knappe, DRU AU - Iwaki, K AU - Ohira, H T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - The principal objective of this study was to elucidate mechanisms by which NOM affects the adsorption of a nonpolar (simazine) and a polar (asulam) herbicide on activated carbon. Experiments were carried out in microcolumns that were continuously fed solutions containing NOM with different molecular weight (MW) distributions and intermittently solutions containing the same NOM plus simazine or asulam. The MW distributions of a groundwater NOM were altered by coagulation and ultrafiltration, which resulted in the preferential removal of high-MW, UV260-absorbing NOM. At a given NOM loading, the simazine removal efficiency was higher in the column that was preloaded with raw groundwater than in columns receiving coagulated or ultrafiltered water. In contrast, the asulam removal efficiency was similar for all three NOM solutions at a given NOM loading. Therefore, the results suggested that low-MW, UV260-absorbing NOM molecules competed directly with strongly adsorbing pesticides, such as simazine, for adsorption sites. For more weakly adsorbing pesticides, such as asulam, direct competition for adsorption sites originated not only from the strongly adsorbing, low-MW NOM, but also from more weakly adsorbing, higher-MW NOM. Consequently, the competing NOM fraction increases as the adsorbability of the SOC decreases, a result that was confirmed by adsorption data for additional pesticides of similar size. However, a smaller pesticide competed more effectively for adsorption sites than a larger pesticide of similar polarity, suggesting that the concentration of competing NOM decreases as the MW of the SOC decreases. DA - 2002/8/1/ PY - 2002/8/1/ DO - 10.1021/es011366u VL - 36 IS - 15 SP - 3432-3438 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036667665&partnerID=MN8TOARS ER - TY - JOUR TI - Pesticide adsorption by granular activated carbon adsorbers. 1. Effect of natural organic matter preloading on removal rates and model simplification AU - Matsui, Y AU - Knappe, DRU AU - Takagi, R T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - The adsorptive removal of periodic spikes of the trace synthetic organic chemicals (SOCs) simazine and asulam from water containing natural organic matter (NOM) was studied in pilot-scale granular activated carbon (GAC) adsorbers over a period of nearly 3 years. The SOC removal percentage obtained at any preloading time and bed depth was independent of the liquid-phase SOC concentration, and equations derived from the ideal adsorbed solution theory and a pore surface diffusion model validated this observation. The pseudo-steady-state SOC removal rate, (dC/dz), at each preloading time and bed depth was therefore first order with respectto the liquid-phase SOC concentration, C. Furthermore, the removal modulus, k, in the resulting SOC removal rate expression was a reflection of the solid-phase concentration of the NOM fraction that interfered with the adsorption of SOCs. Analysis of the removal modulus values indicated that the mass transfer zone of the NOM fraction competing with asulamtraveled more rapidlythrough the GAC adsorber than that competing with simazine. Given the similar molecular sizes of the targeted SOCs, this result was primarily explained by differences in SOC adsorbabilities, where the more weakly adsorbing asulam was less capable of displacing preloaded NOM. Consequently, the NOM fraction competing with asulam constituted a larger percentage of the total NOM than that competing with simazine. DA - 2002/8/1/ PY - 2002/8/1/ DO - 10.1021/es0113652 VL - 36 IS - 15 SP - 3426-3431 SN - 1520-5851 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036667663&partnerID=MN8TOARS ER - TY - JOUR TI - Effects of activated carbon surface chemistry and pore structure on the adsorption of organic contaminants from aqueous solution AU - Li, L AU - Quinlivan, PA AU - Knappe, DRU T2 - CARBON AB - The objective of this research was to develop activated carbon selection criteria that assure the effective removal of trace organic contaminants from aqueous solution and to base the selection criteria on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, a matrix of activated carbon fibers (ACFs) with three activation levels and four surface chemistry levels was prepared and characterized. In addition, three granular activated carbons (GACs) were studied. Two common drinking water contaminants, relatively polar methyl tertiary-butyl ether (MTBE) and relatively nonpolar trichloroethene (TCE), served as adsorbate probes. TCE adsorbed primarily in micropores in the 7–10 Å width range while MTBE adsorbed primarily in micropores in the 8–11 Å width range. These results suggest that effective adsorbents should exhibit a large volume of micropores with widths that are about 1.3 to 1.8 times larger than the kinetic diameter of the target adsorbate. Hydrophobic adsorbents more effectively removed both TCE and MTBE from aqueous solution than hydrophilic adsorbents, a result that was explained by enhanced water adsorption on hydrophilic surfaces. To assure sufficient adsorbent hydrophobicity, the oxygen and nitrogen contents of an activated carbon should therefore sum to no more than about 2 to 3 mmol/g. DA - 2002/// PY - 2002/// DO - 10.1016/S0008-6223(02)00069-6 VL - 40 IS - 12 SP - 2085-2100 SN - 1873-3891 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036042422&partnerID=MN8TOARS KW - activated carbon, carbon fibers KW - chemical treatment, surface treatment KW - adsorption KW - adsorption properties, microporosity ER - TY - JOUR TI - Critical evaluation of factors required to terminate the postclosure monitoring period at solid waste landfills AU - Barlaz, MA AU - Rooker, AP AU - Kjeldsen, P AU - Gabr, MA AU - Borden, RC T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Regulations governing the disposal of solid waste in landfills specify that they must be monitored for 30 years after closure unless this period is extended by the governing regulatory authority. Given the wide range of conditions under which refuse is buried, technical criteria, rather than a specific time period, are preferable for evaluation of when it is acceptable to terminate postclosure monitoring. The objectives of this paper are to identify and evaluate parameters that can be used to define the end of the postclosure monitoring period and to present a conceptual framework for an investigation of whether postclosure monitoring can be terminated at a landfill. Parameters evaluated include leachate composition and leachate and gas production. Estimates of leachate production from closed landfills are used to assess the potential environmental impacts of a hypothetical release to surface water or groundwater. The acceptability of gaseous releases should be evaluated against criteria for odors, the potential for subsurface migration, and greenhouse gas and ozone precursor emissions. The approach presented here must be tested on a site-specific basis to identify additional data requirements and regulatory activity that might be required to prepare regulators for the large number of requests to terminate postclosure monitoring expected over the next 20 years. An approach in which the frequency and extent of postclosure monitoring is reduced as warranted by site-specific data and impact analysis should provide an effective strategy to manage closed landfills. DA - 2002/8/15/ PY - 2002/8/15/ DO - 10.1021/es011245u VL - 36 IS - 16 SP - 3457-3464 SN - 1520-5851 ER - TY - JOUR TI - Modified Ritz vector approach for dynamic properties of electrical cabinets and control panels AU - Gupta, A AU - Yang, JF T2 - NUCLEAR ENGINEERING AND DESIGN AB - Often, the simple methods used for evaluating incabinet spectra needed in the seismic qualification of safety related electrical instruments ignore the dynamic characteristics of the electrical control panels and cabinets. Gupta et al. (Nucl. Eng. Des. 190 (1999a) 255) developed a Ritz vector approach for evaluating the dynamic properties of the cabinets and the incabinet spectra. This approach is based on the conclusions drawn from detailed finite element analyses of several cabinets. In the present paper, we illustrate the limitations of the originally proposed Ritz vector approach that were encountered during subsequent applications to actual cabinets. Modifications to the originally proposed formulations are presented and their accuracy evaluated by comparison of results for actual cabinets with the corresponding results obtained from finite element analyses. The modified Ritz vector approach can account for actual rotational constraints imparted by supporting structural members such as stiffeners. It can also be applied to bench board type cabinets in which instruments are mounted on plates or frames that are inclined to the global axes as well as to frames in which parallel frame members can vibrate in different vibration shapes due to differences in boundary conditions and non-uniform mass distribution. DA - 2002/8// PY - 2002/8// DO - 10.1016/S0029-5493(02)00133-4 VL - 217 IS - 1-2 SP - 49-62 SN - 0029-5493 ER - TY - JOUR TI - MTBE and aromatic hydrocarbons in North Carolina stormwater runoff AU - Borden, RC AU - Black, DC AU - McBlief, KV T2 - ENVIRONMENTAL POLLUTION AB - A total of 249 stormwater samples were collected from 46 different sampling locations in North Carolina over an approximate 1-year period and analyzed to identify land use types where fuel oxygenates and aromatic hydrocarbons may be present in higher concentrations and at greater frequency. Samples were analyzed by gas chromatography-mass spectrometry in ion selective mode to achieve a quantitation limit of 0.05 microg/l. m-,p-Xylene and toluene were detected in over half of all samples analyzed, followed by MTBE: o-xylene: 1,3,5-trimethylbenzene: ethylbenzene; and 1,2,4-trimethylbenzene. Benzene, DIPE, TAME and 1,2,3-trimethylbenzene were detected in < 10% of the samples analyzed. Median contaminant concentrations (when detected) varied from 0.07 microg/l for ethylbenzene to 0.11 microg/l for toluene. All of the locations with significantly higher contaminant concentrations were associated with direct runoff from a gas station or discharge of contaminated groundwater from a former leaking underground storage tank. For all of the aromatic hydrocarbons, the maximum observed contaminant concentrations were over an order of magnitude lower than current drinking water standards. DA - 2002/// PY - 2002/// DO - 10.1016/S0269-7491(01)00204-4 VL - 118 IS - 1 SP - 141-152 SN - 1873-6424 KW - MTBE KW - BTEX KW - stormwater KW - runoff KW - oxygenates ER - TY - JOUR TI - Facility location model for booster disinfection of water supply networks AU - Tryby, M. E. AU - Boccelli, D. L. AU - Uber, J. G. AU - Rossman, L. A. T2 - Journal of Water Resources Planning and Management AB - Secondary or postdisinfection is widely used to maintain protective levels of disinfectant within water distribution systems. In contrast to conventional methods that apply disinfectant only at the treatment works, booster disinfection reapplies disinfectant at strategic locations within the distribution system to compensate for the losses that occur as it decays over time. Building on the writers’ previous work, this paper addresses the problem of locating disinfectant booster stations that minimize the dosage required to maintain residuals throughout the supply network, and introduces a useful parameterization for disinfectant source types. The model is related to the general fixed-charge facility location problem and is formulated as a mixed integer linear programming problem. Results for an example network show that disinfectant dosage savings are achievable with the adoption of booster disinfection, and that the rate of savings decreases as the number of booster stations utilized increases. Furthermore, booster disinfection may provide a more even distribution of disinfectant concentrations throughout the network, and has the potential to reduce aggregate exposure of the population to chlorine (and its by-products) while simultaneously improving residual coverage in the periphery of the distribution system. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)0733-9496(2002)128:5(322) VL - 128 IS - 5 SP - 322-333 ER - TY - JOUR TI - Creep and durability of environmentally conditioned FRP-RC beams using fiber optic sensors AU - Singhvi, A. AU - Mirmiran, A. T2 - Journal of Reinforced Plastics and Composites DA - 2002/// PY - 2002/// DO - 10.1106/073168402026254 VL - 21 IS - 4 SP - 351-373 ER - TY - JOUR TI - Correlation of test and FEA results for elbows subjected to out-of-plane loading AU - Tan, Y AU - Wilkins, K AU - Matzen, V T2 - NUCLEAR ENGINEERING AND DESIGN AB - The objective of this study is to validate a finite element analysis (FEA) simulation methodology to predict the out-of-plane behavior of piping elbows. Two out-of-plane elbow experiments and the corresponding FEA shell and elbow element models are presented. For load–displacements results, all the FEA predictions showed excellent agreement with measured experimental results, and for load–strain behavior, the shell FEA model results correlated quite well with the experimental results. DA - 2002/9// PY - 2002/9// DO - 10.1016/S0029-5493(02)00132-2 VL - 217 IS - 3 SP - 213-224 SN - 0029-5493 ER - TY - JOUR TI - Correlation of in-plane bending test and FEA results for thin-walled elbows AU - Tan, Y AU - Matzen, V T2 - NUCLEAR ENGINEERING AND DESIGN AB - The objective of this study is to validate a finite element analysis (FEA) simulation methodology to predict the global behavior of thin-walled elbows subjected to in-plane bending. Two in-plane closing mode bending tests and one in-plane opening mode bending test were conducted on 2″ schedule 10 elbows, and a nonlinear FEA procedure was used to simulate the tests. A detailed FEA study was carried out to determine the relative importance of weld size and location, measured wall thicknesses, and original cross-section dimensions on the reconciliation results. When the weld bead was included in the analysis, the reconciliation results for load–displacement behavior and some of the strain measurements were excellent. For those cases in which the strain measurements reconciliations were not so good, a possible explanation is provided. DA - 2002/8// PY - 2002/8// DO - 10.1016/S0029-5493(02)00137-1 VL - 217 IS - 1-2 SP - 21-39 SN - 1872-759X ER - TY - JOUR TI - Testing and evaluating alternative algorithms for location referencing system route generation AU - Rasdorf, W. AU - Janisch, A. AU - Robson, F. AU - Tilley, C. T2 - Journal of Computing in Civil Engineering AB - Modeling the transportation network of roads and highways for data and information system implementations presents unique challenges. The foremost challenge is selecting a modeling methodology that is compatible with the needs and culture of the organization using it. The second challenge is implementing the model in a viable enterprise information system via a database. Transportation information systems must efficiently store network topology and geometry, as well as attributes, and they must be compatible with geographic information systems (GIS). This paper deals with the topological aspects of the highway network. In particular, it describes computing methodologies for generating location referencing system routes. The paper describes the link node referencing system used to build the routes and mentions an alternative approach using GIS. Various algorithms are presented and described, test case results are presented, the algorithms are compared, and evaluation criteria are defined. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)0887-3801(2002)16:3(194) VL - 16 IS - 3 SP - 194-221 ER - TY - JOUR TI - Ritz vector approach for static and dynamic analysis of plates with edge beams AU - Yang, J AU - Gupta, A T2 - JOURNAL OF SOUND AND VIBRATION AB - A Ritz vector approach is used to develop new formulations for evaluating the static and the dynamic characteristics of rectangular plates with edge beams. Unlike previous studies in which stiffness coefficients with specified distributions along the plate edges are used to represent the effect of edge restraints, the effect of elastic edge restraints is accounted for by including appropriate integrals for edge beams in the expressions for total kinetic and potential energies in a Rayleigh–Ritz approach. The effect of various types of boundary conditions at the beam ends is accounted for by considering the corresponding Ritz vectors. The contribution of beam mass to the total kinetic energy is also considered in the proposed approach. This effect has often been neglected in the previous studies but can be significant in some applications. The results obtained from the application of the proposed approach to a variety of examples are compared with the corresponding results obtained from the finite element analysis. DA - 2002/5/30/ PY - 2002/5/30/ DO - 10.1006/jsvi.2001.4047 VL - 253 IS - 2 SP - 373-388 SN - 0022-460X ER - TY - JOUR TI - Stability tests of sandwich composite elastica arches AU - Amde, A. M. AU - Mirmiran, A. AU - Nelsen, D. T2 - Journal of Structural Engineering (New York, N.Y.) DA - 2002/// PY - 2002/// VL - 128 IS - 5 SP - 683-686 ER - TY - JOUR TI - SMiRT 15 - Selected and updated papers from the 15(th) International Conference on Structural Mechanics in Reactor Technology - Seoul, Republic of Korea - Preface AU - Tung, DCC T2 - NUCLEAR ENGINEERING AND DESIGN DA - 2002/3// PY - 2002/3// DO - 10.1016/S0029-5493(01)00466-6 VL - 212 IS - 1-3 SP - IX-IX SN - 0029-5493 ER - TY - JOUR TI - Quantification of variability and uncertainty in lawn and garden equipment NOx and total hydrocarbon emission factors AU - Frey, HC AU - Bammi, S T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Variability refers to real differences in emissions among multiple emission sources at any given time or over time for any individual emission source. Variability in emissions can be attributed to variation in fuel or feedstock composition, ambient temperature, design, maintenance, or operation. Uncertainty refers to lack of knowledge regarding the true value of emissions. Sources of uncertainty include small sample sizes, bias or imprecision in measurements, nonrepresentativeness, or lack of data. Quantitative methods for characterizing both variability and uncertainty are demonstrated and applied to case studies of emission factors for lawn and garden (L&G) equipment engines. Variability was quantified using empirical and parametric distributions. Bootstrap simulation was used to characterize confidence intervals for the fitted distributions. The 95% confidence intervals for the mean grams per brake horsepower/hour (g/hp-hr) emission factors for two-stroke engine total hydrocarbon (THC) and NOx emissions were from -30 to +41% and from -45 to +75%, respectively. The confidence intervals for four-stroke engines were from -33 to +46% for THCs and from -27 to +35% for NOx. These quantitative measures of uncertainty convey information regarding the quality of the emission factors and serve as a basis for calculation of uncertainty in emission inventories (EIs). DA - 2002/4// PY - 2002/4// DO - 10.1080/10473289.2002.10470792 VL - 52 IS - 4 SP - 435-448 SN - 1047-3289 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036228881&partnerID=MN8TOARS ER - TY - JOUR TI - Portable autonomous vertical profiler for estuarine applications AU - Reynolds-Fleming, JV AU - Fleming, JG AU - Luettich, RA T2 - ESTUARIES DA - 2002/2// PY - 2002/2// DO - 10.1007/BF02696058 VL - 25 IS - 1 SP - 142-147 SN - 0160-8347 ER - TY - JOUR TI - Nonlinear continuity analysis of precast prestressed girders with cast-in-place decks and diaphragms - Authors' closure AU - Mirmiran, A. AU - Kulkarni, S. AU - Castrodale, R. AU - Miller, R. AU - Hastak, M. T2 - PCI Journal DA - 2002/// PY - 2002/// VL - 47 IS - 3 SP - 115-118 ER - TY - JOUR TI - Flexural Behavior of concrete-filled fiber-reinforced polymer circular tubes AU - Fam, A. Z. AU - Rizkalla, S. H. T2 - Journal of Composites for Construction AB - This paper presents the experimental results of large-scale concrete-filled glass fiber reinforced polymer (GFRP) circular tubes and control hollow GFRP and steel tubes tested in bending. The diameter of the beams ranged from 89 to 942 mm and the spans ranged from 1.07 to 10.4 m. The study investigated the effects of concrete filling, cross-sectional configurations including tubes with a central hole, tube-in-tube with concrete filling in between, and different laminate structures of the GFRP tubes. The study demonstrated the benefits of concrete filling, and showed that a higher strength-to-weight ratio can be achieved by providing a central hole. The results indicated that the flexural behavior is highly dependent on the stiffness and diameter-to-thickness ratio of the tube, and, to a much less extent, on the concrete strength. Test results suggest that the contribution of concrete confinement to the flexural strength is insignificant; however, the ductility of the member is improved. A strain compatibility model has been developed, verified by the experimental results, and used to provide a parametric study of the different parameters, significantly affecting the behavior. The parametric study covered a wide range of FRP sections filled with concrete, including under-reinforced, balanced, and over-reinforced sections. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)1090-0268(2002)6:2(123) VL - 6 IS - 2 SP - 123-132 ER - TY - JOUR TI - Fiber-Reinforced Polymer Composites in Construction- State-of-the-Art Review AU - Bakis, C. AU - Bank, L. AU - Brown, V. AU - Cosenza, E. AU - Davalos, J. AU - Lesko, J. AU - Machida, A. AU - Rizkalla, S. AU - Triantafillou, T. T2 - ASCE Journal of Composites for Construction AB - A concise state-of-the-art survey of fiber-reinforced polymer (also known as fiber-reinforced plastic) composites for construction applications in civil engineering is presented. The paper is organized into separate sections on structural shapes, bridge decks, internal reinforcements, externally bonded reinforcements, and standards and codes. Each section includes a historical review, the current state of the art, and future challenges. DA - 2002/5// PY - 2002/5// DO - 10.1061/(ASCE)1090-0268(2002)6:2(73) VL - 6 IS - 2 SP - 78–87 ER - TY - JOUR TI - Engineering, design and construction of lunar bases AU - Benaroya, H. AU - Bernold, L. AU - Chua, K. M. T2 - Journal of Aerospace Engineering DA - 2002/// PY - 2002/// VL - 15 IS - 2 SP - 33-45 ER - TY - JOUR TI - Time-dependent behavior of fiber-reinforced polymer-confined concrete columns under axial loads AU - Naguib, W. AU - Mirmiran, A. T2 - ACI Structural Journal DA - 2002/// PY - 2002/// VL - 99 IS - 2 SP - 142-148 ER - TY - JOUR TI - Refuse decomposition in the presence and absence of leachate recirculation AU - Mehta, R. AU - Barlaz, Morton AU - Yazdani, R. AU - Augenstein, D. AU - Bryars, M. AU - Sinderson, L. T2 - Journal of Environmental Engineering (New York, N.Y.) AB - A side by side comparison of two 8,000 metric ton test cells was performed to evaluate the effects of leachate recirculation on refuse decomposition at Yolo County, CA. After about 3 years of operation, refuse was excavated in three borings from the enhanced cell (E1, E2, and E3) and two borings from the control cell (C1 and C2). Refuse moisture content data show that leachate recirculation resulted in an increase in refuse moisture content, but also show that the refuse in the enhanced cell was not uniformly wet. The average moisture content in E1, E2, and E3 was 38.8, 31.7, and 34.8%, respectively, while the average moisture content in C1 and C2 was 14.6 and 19.2%, respectively. Leachate recirculation resulted in both higher methane yields, (63.1 versus 27.9 L CH4/wet-kg over 1231 days) and increased settlement (15.5% versus 3% of the waste thickness). The extent of decomposition of excavated refuse samples was determined by the biochemical methane potential (BMP) and the ratio of cellulose plus hemicellulose to lignin [(C+H)/Li]. Solids analyses showed the average BMP in the enhanced and control cells to be 24.0 and 30.9 mL CH4/dry-g, respectively. The corresponding (C+H)/Li ratios were 1.09 and 1.44, respectively. These data correlate well with the increased methane production in the enhanced cell. Thus laboratory and field data show more decomposition in the enhanced cell relative to the control cell. The refuse sampling program conducted for the Yolo County test cells, in concert with data on settlement, methane production, and the volume of liquid actually recycled, represents perhaps the most complete set of data available to date on a field-scale leachate recirculation landfill. DA - 2002/// PY - 2002/// DO - 10.1061/(asce)0733-9372(2002)128:3(228) VL - 128 IS - 3 SP - 228–236 ER - TY - JOUR TI - Optimization of activated sludge designs using genetic algorithms AU - Doby, TA AU - Loughlin, DH AU - Reyes, FL AU - Ducoste, JJ T2 - WATER SCIENCE AND TECHNOLOGY AB - We describe a framework in which a genetic algorithm (GA) and a static activated sludge (AS) treatment plant design model (WRC AS model) are used to identify low cost activated sludge designs that meet specified effluent limits (e.g. for BOD, N, and P). Once the user has chosen a particular process (Bardenpho, Biodenipho, UCT or SBR), this approach allows the parameterizations for each AS unit process to be optimized systematically and simultaneously. The approach is demonstrated for a wastewater treatment plant design problem and the GA-based performance is compared to that of a classical nonlinear optimization approach. The use of GAs for multiobjective problems such as AS design is demonstrated and their application for reliability-based design and alternative generation is discussed. DA - 2002/// PY - 2002/// DO - 10.2166/wst.2002.0106 VL - 45 IS - 6 SP - 187-198 SN - 0273-1223 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000175103800019&KeyUID=WOS:000175103800019 KW - activated sludge KW - design KW - genetic algorithms KW - optimization KW - wastewater treatment ER - TY - JOUR TI - Introduction to special section on sensitivity analysis and summary of NCSU/USDA workshop on sensitivity analysis AU - Frey, HC T2 - RISK ANALYSIS AB - This guest editorial is a summary of the NCSU/USDA Workshop on Sensitivity Analysis held June 11-12, 2001 at North Carolina State University and sponsored by the U.S. Department of Agriculture's Office of Risk Assessment and Cost Benefit Analysis. The objective of the workshop was to learn across disciplines in identifying, evaluating, and recommending sensitivity analysis methods and practices for application to food-safety process risk models. The workshop included presentations regarding the Hazard Assessment and Critical Control Points (HACCP) framework used in food-safety risk assessment, a survey of sensitivity analysis methods, invited white papers on sensitivity analysis, and invited case studies regarding risk assessment of microbial pathogens in food. Based on the sharing of interdisciplinary information represented by the presentations, the workshop participants, divided into breakout sessions, responded to three trigger questions: What are the key criteria for sensitivity analysis methods applied to food-safety risk assessment? What sensitivity analysis methods are most promising for application to food safety and risk assessment? and What are the key needs for implementation and demonstration of such methods? The workshop produced agreement regarding key criteria for sensitivity analysis methods and the need to use two or more methods to try to obtain robust insights. Recommendations were made regarding a guideline document to assist practitioners in selecting, applying, interpreting, and reporting the results of sensitivity analysis. DA - 2002/6// PY - 2002/6// DO - 10.1111/0272-4332.00037 VL - 22 IS - 3 SP - 539-545 SN - 0272-4332 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036085220&partnerID=MN8TOARS KW - sensitivity analysis KW - food safety uncertainty KW - variability modeling ER - TY - CONF TI - Identification and review of sensitivity analysis methods AU - Frey, H. Christopher AU - Patil, S.R. AB - Identification and qualitative comparison of sensitivity analysis methods that have been used across various disciplines, and that merit consideration for application to food‐safety risk assessment models, are presented in this article. Sensitivity analysis can help in identifying critical control points, prioritizing additional data collection or research, and verifying and validating a model. Ten sensitivity analysis methods, including four mathematical methods, five statistical methods, and one graphical method, are identified. The selected methods are compared on the basis of their applicability to different types of models, computational issues such as initial data requirement and complexity of their application, representation of the sensitivity, and the specific uses of these methods. Applications of these methods are illustrated with examples from various fields. No one method is clearly best for food‐safety risk models. In general, use of two or more methods, preferably with dissimilar theoretical foundations, may be needed to increase confidence in the ranking of key inputs. C2 - 2002/// C3 - Risk Analysis DA - 2002/// DO - 10.1111/0272-4332.00039 VL - 22 SP - 553-578 M1 - 3 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036085488&partnerID=MN8TOARS ER - TY - JOUR TI - Analysis and field tests on the performance of composite tubes under pile driving impact AU - Mirmiran, A AU - Shao, YT AU - Shahawy, M T2 - COMPOSITE STRUCTURES AB - Composite tubes provide a feasible alternative to concrete piles by eliminating formwork, reinforcing cage, and additional corrosion-deterrent cover. Field driving of concrete-filled composite tubes showed no damage to the tube or concrete. Driving stresses in filled tubes were found comparable to those for prestressed concrete piles. Empty tubes may buckle or rupture under driving impact, unless driven at shallow depths and in soft soils, or with a steel mandrel. A detailed parametric study using the wave equation further confirmed that there is no difference in the drivability of filled FRP tubes and prestressed concrete piles of the same cross-sectional area and concrete strength. The typical refusal rate for conventional concrete piles can be safely adopted for filled tubes. However, empty tubes are susceptible to compression failure, and can only endure diving stresses up to 40–50% of the refusal rate of concrete piles. DA - 2002/2// PY - 2002/2// DO - 10.1016/S0263-8223(01)00140-4 VL - 55 IS - 2 SP - 127-135 SN - 0263-8223 KW - composite tube KW - impact KW - pile driving KW - wave equation ER - TY - CONF TI - Role of internal nutrient storage in duckweed for secondary swine wastewater treatment AU - Chaiprapat, S. AU - Cheng, J. AU - Classen, J. J. AU - Liehr, S. K. C2 - 2002/// C3 - Paper, 2002 ASAE annual international meeting/CIGR XVth world congress : Hyatt Regency Chicago, Chicago, Illinois, USA, July 28 - July 31, 2002 DA - 2002/// VL - 2 SP - 4130 ER - TY - JOUR TI - Field evaluation of lane selection strategies at signalized intersections AU - Nevers, B. AU - Rouphail, N. T2 - Journal of Transportation Engineering DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)0733-947X VL - 128 IS - 3 SP - 224-231 ER - TY - JOUR TI - The history of the B-2 stress index AU - Matzen, VC AU - Tan, Y T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - The history of the primary stress design equations for Class 1 and 2 elbows in the ASME Boiler and Pressure Vessel Code (Section III, Division 1, Subsections NB and NC) is reviewed. The review includes the early analytical solutions for elbow bending, Markl’s stress-intensification factor, the development of Code equation (9), the relationship between SIFs and the C2 and B2 stress indices, development of B2 equations that are functions of internal pressure and bend angle, and a suggested definition of the B2 index which is based on nonlinear finite element analysis. DA - 2002/5// PY - 2002/5// DO - 10.1115/1.1464564 VL - 124 IS - 2 SP - 168-176 SN - 0094-9930 ER - TY - JOUR TI - Modeling cometabolism of cyclic ethers AU - Zenker, MJ AU - Borden, RC AU - Barlaz, MA T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - The biodegradation kinetics of a mixed culture with the ability to cometabolically degrade 1,4-dioxane in the presence of tetrahydrofuran (THF) were studied using a previously published model. Based on a series of batch experiments, the maximum specific utilization rates were determined to be 1.09 mg THF/mg TSS-day and 0.45 mg 1,4-dioxane/mg TSS-day. Half-saturation coefficients of 10.8 mg THF/L and 12.6 mg 1,4-dioxane/L were measured. There was no evidence that 1,4-dioxane biodegradation produced toxic by-products and the presence of 1,4-dioxane did not inhibit THF biodegradation. However, THF may competitively inhibit 1,4-dioxane biodegradation. The model was capable of predicting the biodegradation of 1,4-dioxane and THF at 1,4-dioxane:THF molar ratios of 0.9–3.3. DA - 2002/// PY - 2002/// DO - 10.1089/109287502760271535 VL - 19 IS - 4 SP - 215-228 SN - 1092-8758 KW - 1,4-dioxane KW - cometabolism KW - kinetics KW - tetrahydrofuran KW - ethers KW - biodegradation ER - TY - JOUR TI - Estimating sliding displacement of an unanchored body subjected to earthquake excitation AU - Choi, B AU - Tung, CCD T2 - EARTHQUAKE SPECTRA AB - A freestanding rigid body under the action of base excitation can move in many different ways. In this study, the sliding response of a body is considered. The body is placed on a horizontal base that undergoes a one-dimensional horizontal motion. In 1965, Newmark (1965) gave a simple formula to determine the sliding distance of a freestanding body subjected to a single rectangular acceleration pulse of short duration at the base. The objective of this study is to see if this formula can be applied to estimate the sliding displacement of a body under the action of real earthquakes. Newmark's formula calls for the maximum velocity of the base which information is usually not directly available. To make use of the response spectrum commonly available to the engineers, Newmark's formula is first re-derived and expressed in terms of the maximum displacement of the base, which can be determined from the absolute displacement response spectrum in low frequency range. An ensemble of 75 real earthquakes is then employed, the equation of sliding motion is solved numerically and the average of the maximum sliding displacement of the body relative to the base is computed. The computed displacement is then compared with that obtained by Newmark's formula. This is done for a body placed on the ground as well as on the floors of a building. It is shown that Newmark's formula can be used if an adjustment factor, as suggested in this study, is applied. Key words: earthquake, sliding, unanchored body DA - 2002/11// PY - 2002/11// DO - 10.1193/1.1516750 VL - 18 IS - 4 SP - 601-613 SN - 8755-2930 ER - TY - JOUR TI - Correlation of test and FEA results for the nonlinear behavior of straight pipes and elbows AU - Tan, Y AU - Matzen, VC AU - Yu, LX T2 - JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME AB - This paper summarizes the literature on reconciliation of finite element analyses with in-plane bending experiments on piping elbows. It then describes in detail two four-point-bending tests on straight pipes and two in-plane bending tests on elbows and the corresponding nonlinear finite element analyses. Using a new procedure for obtaining a stress-strain curve for stainless steel using only values for E,Sy, and Su and a representative stress-strain curve from a test on a similar material specimen, the nonlinear responses of the piping components tested are shown to be simulated more accurately than previously published results. DA - 2002/11// PY - 2002/11// DO - 10.1115/1.1493806 VL - 124 IS - 4 SP - 465-475 SN - 1528-8978 ER - TY - JOUR TI - Timber beams strengthened with GFRP bars: Development and applications AU - Gentile, C. AU - Svecova, D. AU - Rizkalla, S. H. T2 - Journal of Composites for Construction AB - Repair and rehabilitation of infrastructure is becoming increasingly important for bridges due to material deterioration and limited capacity to accommodate current load levels. An experimental program was undertaken to study the flexural behavior of creosote-treated sawn Douglas fir timber beams strengthened with glass fiber-reinforced polymer (GFRP) bars. Twenty-two half-scale and four full-scale timber beams strengthened with GFRP were tested to failure. The percent reinforcement ratios were between 0.27 and 0.82%. Additional unreinforced timber beams were tested as control specimens. The results have shown that using the proposed experimental technique changed the failure mode from brittle tension to compression failure, and flexural strength increased by 18 to 46%. Research findings indicate the use of near-surface GFRP bars overcomes the effect of local defects in the timber and enhances the bending strength of the members. Based on the experimental results, an analytical model is proposed to predict the flexural capacity of both unreinforced and GFRP-reinforced timber beams. The article also reviews implementation of the proposed technique for strengthening a timber bridge near Winnipeg, Manitoba, Canada. DA - 2002/// PY - 2002/// DO - 10.1061/(ASCE)1090-0268(2002)6:1(11) VL - 6 IS - 1 SP - 11-20 ER - TY - JOUR TI - Redundancy in residual vectors for missing mass effect in coupled modal synthesis AU - Zhao, J. AU - Gupta, A. T2 - Journal of Structural Engineering (New York, N.Y.) AB - It has been illustrated in the past that a modal synthesis gives incorrect modal properties and seismic response of nonclassically damped coupled systems when all the modes of uncoupled primary and secondary systems are not included. The effect of missing mass contained in the truncated high frequency modes can be represented using residual modal vectors. This paper illustrates two possibilities in which the residual modal matrix may contain redundant vectors leading to a breakdown of the originally proposed method. First, secondary systems with a support inclined to the primary system orthogonal connecting degrees of freedom can have residual vectors that are scalar multiple of each other (parallel). Second, the number of residual and nonrigid modal vectors can be more than the total number of secondary system modes (equal to the number of secondary system degrees of freedom) in multiply connected simple secondary systems. A solution is presented to identify and eliminate both these types of redundant vectors using an alternative form of Gram-Schmidt’s orthogonalization. DA - 2002/// PY - 2002/// DO - 10.1061/(asce)0733-9445(2002)128:9(1231) VL - 128 IS - 9 SP - 1231-1235 ER - TY - JOUR TI - Optimizing ferric sulfate coagulation of algae with streaming current measurements AU - Briley, D.S. AU - Knappe, D.R.U. T2 - Journal / American Water Works Association AB - This study sought to determine ferric sulfate coagulation conditions that lead to effective removal of algae by conventional gravity sedimentation. Using laboratory‐cultured Anabaena flos‐aquae spiked into natural water, charge titrations and jar tests were conducted to evaluate the effects of streaming current value, coagulation pH, and initial algae concentration on the removal of algae, turbidity, and natural organic matter. At pH 6, ferric sulfate doses corresponding to the point of zero charge (PZC), as determined by streaming current measurements, consistently produced low settled water algae concentrations when an anionic flocculant aid was added. In contrast, ferric sulfate coagulation at pH 7.0 and 7.5 was not effective for algae removal because the algae's surface charge could not be sufficiently neutralized. At pH 6 and the PZC, settled water algae concentrations, turbidity, and ultraviolet absorbance at 254 nm were similar for tests conducted at initial algae concentrations of 10,000 and 50,000 cells/mL, but a larger coagulant dose was required to reach the PZC at the higher initial algae concentration. Thus, adjusting coagulant doses based on streaming current value should be effective for maintaining settled water quality in plants that treat waters with rapidly varying influent algae concentrations and/or background water quality. Experiments conducted with a natural algae bloom sample confirmed that ferric sulfate coagulation at pH 6 and the PZC was effective for algae removal. DA - 2002/// PY - 2002/// DO - 10.1002/j.1551-8833.2002.tb09409.x VL - 94 IS - 2 SP - 80-90 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0036477973&partnerID=MN8TOARS ER - TY - JOUR TI - Fuzzy neural network models for liquefaction prediction AU - Rahman, MS AU - Wang, J T2 - SOIL DYNAMICS AND EARTHQUAKE ENGINEERING AB - Integrated fuzzy neural network models are developed for the assessment of liquefaction potential of a site. The models are trained with large databases of liquefaction case histories. A two-stage training algorithm is used to develop a fuzzy neural network model. In the preliminary training stage, the training case histories are used to determine initial network parameters. In the final training stage, the training case histories are processed one by one to develop membership functions for the network parameters. During the testing phase, input variables are described in linguistic terms such as ‘high’ and ‘low’. The prediction is made in terms of a liquefaction index representing the degree of liquefaction described in fuzzy terms such as ‘highly likely’, ‘likely’, or ‘unlikely’. The results from the model are compared with actual field observations and misclassified cases are identified. The models are found to have good predictive ability and are expected to be very useful for a preliminary evaluation of liquefaction potential of a site for which the input parameters are not well defined. DA - 2002/9// PY - 2002/9// DO - 10.1016/S0267-7261(02)00059-3 VL - 22 IS - 8 SP - 685-694 SN - 0267-7261 KW - earthquake KW - soil KW - liquefaction KW - ground failure KW - fuzzy neural network models ER - TY - JOUR TI - Chlorinated solvent cleanup with edible oils AU - Borden, B. T2 - Pollution Engineering DA - 2002/// PY - 2002/// VL - 34 IS - 10 SP - 16-19 ER - TY - JOUR TI - A displacement-based approach for the seismic design of continuous concrete bridges AU - Kowalsky, MJ T2 - EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS AB - Abstract A displacement‐based design procedure for continuous concrete bridges is proposed which can be incorporated into a performance‐based design philosophy. The procedure is applicable to multi‐degree‐of‐freedom bridges with flexible or rigid superstructures, and for varying degrees of abutment restraint. The background and development of the design procedure is presented first, followed by a series of examples and validation studies using dynamic inelastic time‐history analysis. The procedure is applied to the transverse response of bridge structures; however, it is equally well‐suited for longitudinal response. The results indicate that the process is able to capture non‐linear deformation patterns and thus reasonably control damage. Copyright © 2001 John Wiley & Sons, Ltd. DA - 2002/3// PY - 2002/3// DO - 10.1002/eqe.150 VL - 31 IS - 3 SP - 719-747 SN - 0098-8847 KW - displacement-based design KW - bridges KW - limit states ER -