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Articles 2101 - 2130 of 2295

Full-Text Articles in Architecture

An Optimized Lifetime Reliability-Based Inspection Program For Deteriorating Structures, Allen C. Estes, Dan M. Frangopol Jul 2000

An Optimized Lifetime Reliability-Based Inspection Program For Deteriorating Structures, Allen C. Estes, Dan M. Frangopol

Architectural Engineering

No matter how well they are designed, all civil engineering structures will deteriorate over time and a program of lifetime inspection, maintenance and repair represents a substantial portion of the total lifetime cost of most structures. An optimized inspection program is the key to making appropriate repairs at the right time to minimize cost and maintain an appropriate level of safety in a structure. When a visual inspection will not provide the necessary level of information, some other non-destructive evaluation method is often needed. This study summarizes a methodology for optimizing the timing, the frequency, and the type of inspection …

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Effects Of Ozone/Hydrogen Peroxide Pretreatment On Aerobic Biodegradability Of Nonionic Surfactants And Polypropylene Glycol, Mehmet Kitis, Craig D. Adams, John Kuzhikannil, Glen T. Daigger Jun 2000

Effects Of Ozone/Hydrogen Peroxide Pretreatment On Aerobic Biodegradability Of Nonionic Surfactants And Polypropylene Glycol, Mehmet Kitis, Craig D. Adams, John Kuzhikannil, Glen T. Daigger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Studies were conducted which used the ozone/hydrogen peroxide (O3/H2O2) advanced oxidation process to pretreat three classes of compounds prior to aerobic biological treatment. The study compounds included ethylene oxide/propylene oxide (EO/PO) block copolymers, polypropylene glycols (PPGs), linear secondary alcoholethoxylates (LSAES), and alkylphenolethoxylates (APEs). After preoxidation with ozone and hydrogen peroxide (added at their stoichiometric ratio), 300 mg/L as COD samples were bioassayed in aerobic batch bioassays with a mixed liquor suspended solids concentration of 1500 mg/L. It was found that unoxidized polypropylated compounds (EO/PO block copolymers and PPGs) and LSAEs tended to be biorecalcitrant, …

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Improving Shear Capacity Of Existing Rc T-Section Beams Using Cfrp Composites, Ahmed Khalifa, Antonio Nanni Jun 2000

Improving Shear Capacity Of Existing Rc T-Section Beams Using Cfrp Composites, Ahmed Khalifa, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents the shear performance of reinforced concrete (RC) beams with T-section. Different configurations of externally bonded carbon fiber-reinforced polymer (CFRP) sheets were used to strengthen the specimens in shear. The experimental program consisted of six full-scale, simply supported beams. One beam was used as a benchmark and five beams were strengthened using different configurations of CFRP. The parameters investigated in this study included wrapping schemes, CFRP amount, 90°/0° ply combination, and CFRP end anchorage. The experimental results show that externally bonded CFRP can increase the shear capacity of the beam significantly. In addition, the results indicated that the …

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Empirical Prediction Of Shear Modulus And Young's Modulus Of Plywood Panels, Edmond P. Saliklis, Bora Tokyay May 2000

Empirical Prediction Of Shear Modulus And Young's Modulus Of Plywood Panels, Edmond P. Saliklis, Bora Tokyay

Architectural Engineering

No abstract provided.

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Deformation In Concrete With External Cfrp Sheet Reinforcement, Joseph M. Tripi, Charles E. Bakis, Thomas E. Boothby, Antonio Nanni May 2000

Deformation In Concrete With External Cfrp Sheet Reinforcement, Joseph M. Tripi, Charles E. Bakis, Thomas E. Boothby, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A detailed experimental investigation of local and global deformations of tensile loaded, cracked, rectangular, concrete prisms reinforced with externally bonded carbon fiber reinforced polymer (CFRP) sheets was carried out. High and low modulus sheets were applied using three different thicknesses of epoxy interlayer between the sheet and concrete. It was found that the stiffness of the CFRP sheet had a dominant effect on global tension stiffening, whereas interlayer thickness had a dominant effect on local load transfer and damage formation. Thicker interlayers transferred load into through-cracked concrete over longer transfer zones, thereby increasing the spacing of subsequent cracks in the …

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Local Bond-Slip Relationship For Frp Reinforcement In Concrete, Francesco Focacci, Antonio Nanni, Charles E. Bakis Feb 2000

Local Bond-Slip Relationship For Frp Reinforcement In Concrete, Francesco Focacci, Antonio Nanni, Charles E. Bakis

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The objective of this paper is to define a rigorous numerical method to calibrate parameters of a given local bond-slip relationship using experimental results of pullout tests, taking into account the distribution of the slip and bond shear stress throughout the bar. The proposed method involves finding parameters of a given bond-slip relationship, such that results of pullout tests can be predicted in terms of applied pullout force and consequent slip at the loaded end and slip at the free end. The method is applied to some experimental data, and the results are discussed. For the application of the proposed …

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Influence Of Hydration Temperature On Durability And Mechanical Property Performance Of Prestressed And Precast High-Performance Concrete Beams, John J. Myers, R. L. Carrasquillo Jan 2000

Influence Of Hydration Temperature On Durability And Mechanical Property Performance Of Prestressed And Precast High-Performance Concrete Beams, John J. Myers, R. L. Carrasquillo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Concrete technology has continued to advance throughout the years to meet the demands of designers and innovative structural systems. With the advent of high-performance concrete (HPC), which contains large amounts of cementitious materials, the investigation of the impact of concrete temperature development during hydration on concrete performance is of keen interest. Match-curing technology was used to investigate the influence of concrete temperature development during hydration on the mechanical and material property performance of prestressed and precast HPC beams. These members were fabricated for use in two recently constructed HPC bridges in Texas. The investigation was conducted in conjunction with the …

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Upgrading Missouri Transportation Infrastructure: Solid Reinforced-Concrete Decks Strengthened With Fiber-Reinforced Polymer Systems, T. Alkhrdaji, Antonio Nanni, R. Mayo Jan 2000

Upgrading Missouri Transportation Infrastructure: Solid Reinforced-Concrete Decks Strengthened With Fiber-Reinforced Polymer Systems, T. Alkhrdaji, Antonio Nanni, R. Mayo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

More than 40 percent of the bridges in the United States need repair, strengthening, or replacement. Because of limited funds, many states are forced to post load restrictions on their bridges as a temporary measure. Recently, fiber-reinforced polymers (FRPs) have emerged as a practical solution for repair or strengthening of highway bridges. Since there are no nationally accepted specifications for design and construction with bonded FRP reinforcement, the Missouri Department of Transportation (MoDOT) has funded a research program aimed at validating the design and analysis procedure through strengthening and testing to failure of bridges under realistic highway loading and conditions. …

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Degradation And Uptake Of Benzene In Laboratory Phytoremediation Studies, Carla Ross, Lisa M. Harrison, Adrian Marsh, Lars Zetterstrom, Joel Gerard Burken Jan 2000

Degradation And Uptake Of Benzene In Laboratory Phytoremediation Studies, Carla Ross, Lisa M. Harrison, Adrian Marsh, Lars Zetterstrom, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Whole-Plant Laboratory Studies, Hybrid Poplar Trees Were Shown to Impact a Variety of Fate and Transport Mechanisms for Benzene. Laboratory Experiments Investigated the Distribution of the Contaminant in the Plant Tissues, Degradation in the Soil Profile, and Volatilization from Both the Soil and Leaf Tissues. a New Testing System Was Developed that Allowed for Rapid Testing that is More Field-Representative Than Earlier Studies. Whole Plants Were Utilized in a Reactor Design that Included Both a Saturated and a Vadose Zone. the Continuous Feed Reactors Were Supplied with a Steady Influent Benzene Stream to Mimic Plume Conditions. the Presence of …

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Chemical Oxidation Of Mtbe Under O2-Rich And O2-Limited Environments Coupled With Biological Degradation Of Oxidation Byproducts, J. Sutherland, B. Panka, Craig D. Adams, Joel Gerard Burken Jan 2000

Chemical Oxidation Of Mtbe Under O2-Rich And O2-Limited Environments Coupled With Biological Degradation Of Oxidation Byproducts, J. Sutherland, B. Panka, Craig D. Adams, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The H2O2/UV Advanced Oxidation Process (AOP) Was Investigated to Determine Byproduct Formation under Different Experimental Conditions (PH, Alkalinity, and H2O2/UV Dose). a Key Factor in the Efficiency of the AOP Was the Dissolved Oxygen Concentration. Gas Chromatography/mass Spectrometry (GC/MS) Analysis Was Used to Identify Byproducts Resulting from Oxidation under Oxygen-Rich and Oxygen-Limited Conditions. Resultant Oxidation Byproducts Were Analyzed for their Susceptibility to Biological Degradation. Biodegradation Rate Constants Were Determined and Modeled for the Primary Byproducts of the Advanced Oxidation Process. Inhibition Resulting from the Presence of Multiple Byproducts in a Biological System Was Investigated as Well. Effects of Process Parameters …

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Applicability Of Ozone In Small Drinking Water Systems, Craig D. Adams, Justin Sutherland Jan 2000

Applicability Of Ozone In Small Drinking Water Systems, Craig D. Adams, Justin Sutherland

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of ozone in water treatment plants is expanding rapidly in the United States. Ozone offers excellent disinfection properties (including chlorine-resistant pathogens) and does not form trihalomethanes. Additionally, ozone can be used to achieve or control many other water quality parameters such as color, taste and odor, and inorganic and organic contaminant concentrations. Control of ozone's disinfection byproducts such as bromate (formed in high bromide waters) is required. This presentation will review the synergistic effects of ozone applicable to use in small water treatment plants.

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Accumulation Of Heavy Metals By Vegetables Grown In Mine Wastes, George P. Cobb, Kristin Sands, Melissa Waters, Bobby G. Wixson, Elaine Dorward-King Jan 2000

Accumulation Of Heavy Metals By Vegetables Grown In Mine Wastes, George P. Cobb, Kristin Sands, Melissa Waters, Bobby G. Wixson, Elaine Dorward-King

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Lead, cadmium, arsenic, and zinc were quantified in mine wastes and in soils mixed with mine wastes. Metal concentrations were found to be heterogeneous in the wastes. Iceberg lettuce, Cherry Belle radishes, Roma bush beans, and Better Boy tomatoes were cultivated in mine wastes and in waste-amended soils. Lettuce and radishes had 100% survival in the 100% mine waste treatments compared to 0% and 25% survival for tomatoes and beans, respectively. Metal concentrations were determined in plant tissues to determine uptake and distribution of metals in the edible plant parts. Individual soil samples were collected beneath each plant to assess …

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Biotreatment And Chemical Speciation Of Lead And Zinc Mine/Mill Wastewater Discharges In Missouri, U.S.A., Mujde Erten-Unal, Bobby G. Wixson Nov 1999

Biotreatment And Chemical Speciation Of Lead And Zinc Mine/Mill Wastewater Discharges In Missouri, U.S.A., Mujde Erten-Unal, Bobby G. Wixson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Continued mining development in the world's largest lead producing area has generated and increased concern over effective mine water treatment in Missouri's New Lead Belt. A new type of mine/mill wastewater treatment system was constructed which consisted of a tailings pond followed by a series of artificially constructed meandering biotreatment channels and a polishing lagoon. This system provided additional retention time and distance for the removal of heavy metals by abundant aquatic plants and sedimentation. Seasonal field sampling and analytical testing that evaluated the present system confirmed that it provided good treatment for removal of heavy metals within the company …

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Slip Modulus Of Frp Sheets Bonded To Concrete, Y. J. Lee, T. E. Boothby, C. E. Bakis, Antonio Nanni Nov 1999

Slip Modulus Of Frp Sheets Bonded To Concrete, Y. J. Lee, T. E. Boothby, C. E. Bakis, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

An analytical tension-stiffening model was developed for fiber-reinforced polymer (FRP) sheets bonded to reinforced concrete based on equilibrium equations and the assumption of linear behavior between bond stress and slip. Experimental measurements were made on small- and large-scale specimens. For the small-scale specimens, the primer coat thickness (adhesive thickness between concrete and FRP sheet) was varied for each specimen. By comparisons of the experimental data to the analytical results, the slip modulus at the concrete/FRP sheet and concrete/steel interface was established at the service load level. From this study, it was found that primer coat thickness has a modest influence …

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Evaluation Of Bond Using Frp Rods With Axisymmetric Deformations, Mesfer M. Al-Zahrani, Salah U. Al-Dulaijan, Antonio Nanni, Charles E. Bakis, Thomas E. Boothby Sep 1999

Evaluation Of Bond Using Frp Rods With Axisymmetric Deformations, Mesfer M. Al-Zahrani, Salah U. Al-Dulaijan, Antonio Nanni, Charles E. Bakis, Thomas E. Boothby

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents experimental results obtained with the direct pull-out test using machined and wrapped glass/vinyl ester, carbon/vinyl ester, and carbon/epoxy FRP rods with axisymmetric lugs. The typical results are given as nominal shear stress vs. free- and loaded-end slip. Experimental results obtained from strain probes used during the pull-out test are presented as shear stress vs. strain. Machined glass/vinyl ester FRP rods with embedded lengths including five and 10 lugs, and different lug widths and heights were studied. The failure mode consisted of the shearing off of the lugs without concrete damage. Four concrete mixtures with strengths ranging from …

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Optimum Lifetime Planning Of Bridge Inspection And Repair Programs, Dan M. Frangopol, Allen C. Estes Aug 1999

Optimum Lifetime Planning Of Bridge Inspection And Repair Programs, Dan M. Frangopol, Allen C. Estes

Architectural Engineering

This study proposes a general methodology for determining the optimal lifetime planning of bridge inspection and repair programs based on minimizing the expected cost while maintaining an acceptable level of reliability. For individual bridges, this methodology determines the optimum inspection technique. and the numbers and timing of inspections and repairs. The methodology is demonstrated initially on a simple structure. Then. the method is applied to the optimial planning of inspection and repair programs for an existing bridge. The proposed approach to the problem of lifetime bridge maintenance is shown to be a viable method for optimizing inspection and repair investments …

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Repair Optimization Of Highway Bridges Using System Reliability Approach, Allen C. Estes, Dan M. Frangopol Jul 1999

Repair Optimization Of Highway Bridges Using System Reliability Approach, Allen C. Estes, Dan M. Frangopol

Architectural Engineering

As reliability based methods gain increased acceptance, there is greater opportunity to use scarce resources more efficiently while maintaining a prescribed level of reliability of a structure throughout its service life. The goal is to provide management decisions that will balance lifetime system reliability and expected life-cycle cost in an optimal manner. This study proposes a system reliability approach for optimizing the lifetime repair strategy for highway bridges. The approach is demonstrated using an existing Colorado State highway bridge. The bridge is modeled as a series-parallel combination of failure modes, and the reliability of the overall bridge system is computed …

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Membrane Process For Biological Treatment Of Contaminated Gas Streams, Sarina J. Ergas, Leslee Shumway, Mark W. Fitch, Jeffrey J. Neemann May 1999

Membrane Process For Biological Treatment Of Contaminated Gas Streams, Sarina J. Ergas, Leslee Shumway, Mark W. Fitch, Jeffrey J. Neemann

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A Hollow Fiber Membrane Bioreactor Was Investigated for Control of Air Emissions of Biodegradable Volatile Organic Compounds (VOCs). in the Membrane Bioreactor, Gases Containing VOCs Pass through the Lumen of Microporous Hydrophobic Hollow Fiber Membranes. Soluble Compounds Diffuse through the Membrane Pores and Partition into a VOC Degrading Biofilm. the Hollow Fiber Membranes Serve as a Support for the Microbial Population and Provide a Large Surface Area for VOC and Oxygen Mass Transfer. Experiments Were Performed to Investigate the Effects of Toluene Loading Rate, Gas Residence Time, and Liquid Phase Turbulence on Toluene Removal in a Laboratory-Scale Membrane Bioreactor. Initial …

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Crippling Capacity Of Web Elements With Openings, Roger A. Laboube, W. W. Yu, S. U. Deshmukh, C. A. Uphoff Jan 1999

Crippling Capacity Of Web Elements With Openings, Roger A. Laboube, W. W. Yu, S. U. Deshmukh, C. A. Uphoff

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Commonly used cold-formed steel sections utilized as either wall studs or floor joists contain web holes. The web holes may be factory punched or field cut. Because the Specification for the Design of Cold-Formed Steel Structural Members does not address the potential impact that a web hole can have on the structural integrity of the cold-formed steel member, research was necessary. Researchers at the University of Missouri-Rolla have explored the behavior of a flexural member that possesses a web hole. The scope of the UMR research includes flexure, shear, web crippling, and combinations thereof. The present paper will summarize the …

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Optimized Calibration For Unsteady Flow Modeling Using A Genetic Algorithm, Daniel Sanchez, Jerome A. Westphal Jan 1999

Optimized Calibration For Unsteady Flow Modeling Using A Genetic Algorithm, Daniel Sanchez, Jerome A. Westphal

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The calibration of an unsteady flow model generally relies on the estimation of roughness coefficients, which act as descriptors of friction resistance along the channel. Here an optimized procedure is implemented by incorporating a genetic algorithm (GA) to automate the process. This approach is suitable because discrete parameters are considered. The target is a one-dimensional unsteady flow model in which the roughness coefficient is allowed to vary not only along the river axis, but also dynamically with discharge. The objective function is the root mean square of the difference between measured and computed water levels at a given cross section. …

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Stage-Discharge Relations On The Middle Mississippi River, Jerome A. Westphal, D. B. Thompson, Glendon Taylor Stevens, C. N. Strauser Jan 1999

Stage-Discharge Relations On The Middle Mississippi River, Jerome A. Westphal, D. B. Thompson, Glendon Taylor Stevens, C. N. Strauser

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Based on measurements made on the Middle Mississippi River during the 1993 flood, stage-discharge relations for the rating curve are not single-valued. Analyses of these data suggest that the range of flow rates at a given stage is larger than that attributable to measurement replication error alone. Patterns of stage-discharge measurements also imply a tendency toward hysteresis. However, neither changes in stage nor changes in flow rate correlate with short-term scour and fill at gauging sites.

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Liquefaction Of Silts And Silt-Clay Mixtures, Tianqiang Guo, Shamsher Prakash Jan 1999

Liquefaction Of Silts And Silt-Clay Mixtures, Tianqiang Guo, Shamsher Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Low plasticity silts and silty clays occur extensively in the central United States. For evaluating their liquefaction potential during an earthquake, no guidelines are available based on their density, void ratio, plasticity index, standard penetration values, or any other simple soil property. Their liquefaction behavior is not properly understood at present and is often confused with that of sand-silt mixtures. Pore water pressures and liquefaction in silt and silt-clay mixtures are discussed, and the influences of plasticity index on their cyclic strength are reviewed critically. It is concluded that considerable additional work is needed to fully understand the liquefaction behavior …

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Biological Fixed-Film Systems, Mark W. Fitch, Jeffrey B. Murphy, Stephen S. Sowell Jan 1999

Biological Fixed-Film Systems, Mark W. Fitch, Jeffrey B. Murphy, Stephen S. Sowell

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Microbiological Degradation of Wastewater and its Application using a Fixed-Film Reactor is Reviewed. the Technical and Technological Characteristics, as Well as the Efficiency of Nitrification and Denitrification Processes Were Taken into Consideration. the Review Elucidated the Experimental Measurements of Effective Diffusive Permeabilities and Effective Diffusion Coefficients of Biofilms.

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Natural Treatment And On-Site Processes, Kevin D. White, Joel Gerard Burken Jan 1999

Natural Treatment And On-Site Processes, Kevin D. White, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Natural Treatment Systems, Which is Divided into Land-Treatment, Wetland, Aquatic, Onsite and Small Community, and Phytoremediation Systems, Are Discussed. This Include the Free Water Surface Constructed Wetlands, Subsurface Flow Constructed Wetlands, Vertical Flow Constructed Wetlands,ponds, Floating Aquatic Plant Systems, Solar Aquatic Systems, Small Treatment Systems, and In-Ground Disposals.

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Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor Nov 1998

Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Twelve Organic Compounds Commonly Found at Hazardous Waste Sites Were Studied for Uptake by Hybrid Poplar Trees. the Vegetative Uptake of Many of These Compounds Has Not Previously Been Demonstrated for Plant Species Being Utilized for Phytoremediation, Such as Hybrid Poplar Trees. Experiments Were Conducted Hydroponically Utilizing 14C-Labeled Compounds to Ascertain Translocation and Fate. Predictive Relationships for the Translocation and Partitioning to Plant Tissues Were Developed from the Experimental Data. Translocation and Partitioning Relationships based on Compounds' Octanol- Water Partitioning Coefficients (100 K(Ow)) Produced the Best Results, But the Relationships Did Not Allow for Fully Accurate Prediction of Each Contaminant's …

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Optimum Control Of A Hybrid System For Seismic Excitations With State Observer Technique, Franklin Y. Cheng, Hongping Jiang Oct 1998

Optimum Control Of A Hybrid System For Seismic Excitations With State Observer Technique, Franklin Y. Cheng, Hongping Jiang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a theoretical study of a hybrid seismic response control system comprising a passive fluid viscous damper and an active control system with a hydraulic actuator and acceleration sensors. The analytical model of this system is derived in the discrete time domain with actuator and clamper dynamics considered. Based on digital control theory, a state observer is established for optimal control strategies of the hybrid system. This study shows that the hybrid system gains the advantages of both active and passive control techniques currently in vogue; and that, with the state observer technique, a seismic response control system …

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Gaseous Cah Removal By Biofiltration In Presence And Absence Of A Nonionic Surfactant, J. O. Kim, Purush K. Terkonda, S. D. Lee Jan 1998

Gaseous Cah Removal By Biofiltration In Presence And Absence Of A Nonionic Surfactant, J. O. Kim, Purush K. Terkonda, S. D. Lee

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The objectives of this study were to investigate the biodegradation of gaseous trichloroethylene (TCE) and tetrachloroethylene (PCE) in an activated carbon biofilter inoculated with phenol-oxidizing microorganisms and to study the effect of surfactant concentration below its critical micelle concentration (CMC) on the removal efficiency of TCE or PCE. For the enhanced biofiltration, a biodegradable nonionic surfactant was added to biofilters. The investigation was conducted using two specially built stainless steel biofilters, one for TCE and the other for PCE. The removal efficiency of gaseous TCE was 100% at a residence time of 7 min and its average inlet concentration of …

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Genetic Algorithm Development For Multiobjective Optimization Of Structures, Franklin Y. Cheng, Dan Li Jan 1998

Genetic Algorithm Development For Multiobjective Optimization Of Structures, Franklin Y. Cheng, Dan Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Genetic algorithms (GAs) have the characteristic of maintaing a population of solutions and can search in a parallel manner for many nondominated solutions. These features coincide with the requirement of seeking a Pareto optimal set in a multiobjective (multicriteria, vector) optimization problem. The retionale for multiobjective optimization via GAs is that at each generation, the fitness of each individual is defined according to its nondominated property. Because nondominated individuals are assigned the highest fitness values, the convergence of a population will go th the nondominated zone: the Pareto optimal set. Based on this concept, a Pareto, GA, whose goal is …

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Multiple Objective Structural Optimization With Genetic Algorithm And Fuzzy Logic, Franklin Y. Cheng, Dan Li, Jeffrey J.F. Ger Jan 1998

Multiple Objective Structural Optimization With Genetic Algorithm And Fuzzy Logic, Franklin Y. Cheng, Dan Li, Jeffrey J.F. Ger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a constrained multiobjecthe optimzation method in the form of a robust, practical, problem-independent algorithm, and investigates the effect of multiobjective optimization on structural design. The study includes properties and characteristics of multiobjective optimization and solutions. Design objectives, constraints, and design variables as well as their effect on structural design and behavior are investigated. Fuzzy set theory is also included to construct a fuzzy constrained environment. Two new genetic algorithm operators — multiobjective fitness function and niche method -- are proposed. A new genetic algorithm process, Pareto set filter, is added to genetic algorithms. A 10-story setback building …

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Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord L. Gale, Jerry L. Pitt Jan 1998

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord L. Gale, Jerry L. Pitt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH levels which included "dissolved", …

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