Civil and Environmental Engineering Commons^™

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

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.

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. …

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 …

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.

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.

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 …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

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 …

Bs News

Building Services Engineering

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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 …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

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Urban And Environmental Planning In Nepal, Ambika P. Adhikari

Himalayan Research Papers Archive

This collection of essays deals with issues related to housing, and urban and environmental planning in Nepal. Specific focus is on the planning and environmental problems related to the towns of the Kathmandu Valley.

Nepal is facing several challenges in the areas of urban and environmental management and planning . Rapidly increasing population is exerting pressure in all aspects of urban infrastructure, services and housing. Traditional community support and planning systems are breaking apart due to several factors, such as changing societal values, urban consumption patterns and commercialization of traditionally household activities. On the other hand, Nepali society is not …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

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Bs News

Building Services Engineering

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Bs News

Building Services Engineering

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Bs News

Building Services Engineering

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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 …

Optimizing Multiagent, Multi-Injected Swell Modifier, Marshall B. Addison, Thomas M. Petry

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Interactions of expansive clay soils with transportation facilities have caused billions of dollars of damage. In the process of determining agents and methodologies to overcome expansive clay behavior, multiple injections of chemical agents into the subgrade to modify clay behavior are most promising. A study was conducted to optimize a potassium-rich solution of four parts. The modifying solution has been injected into expansive clay subgrades with success since the early 1970s. A laboratory methodology was developed to inject specimens multiple times and to conduct swell tests. Screening tests were conducted to evaluate linear effects that each of the four constituents …

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 …

Recent Research And Developments In Cold-Formed Steel Framing, Roger A. Laboube, Wei Wen Yu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Recent research studies at the University of Missouri-Rolla (UMR) have focused on developing a better understanding of the behavior of cold-formed steel members and truss assemblies. This research was initiated by the more widespread use of cold-formed steel in the residential construction market, and the need to provide structurally reliable, as well as highly economical design solutions. Steel trusses are commonly assembled using C-shaped sections and self-drilling screws. Based on UMR findings, appropriate design recommendations have been proposed for the web and chord members of a truss. Also of concern is the introduction of large holes in the webs of …

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", …

Hybrid Control Of Seismic Structures With Optimal Placement Of Control Devices, Franklin Y. Cheng, Hongping Jiang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A theoretical study is carried out for optimal controller placement and effectiveness of a hybrid seismic response control system comprising a viscous fluid damper and a servovalve-controlled hydraulic actuator. A stochastic seismic response of controlled structures is first investigated with nonorthogonal damping and stiffness; then a statistical method for optimal placement of control devices on seismic-resistant structures is developed. With such placement, a hybrid system can achieve greater performance in that much less control force is required to reduce structural seismic response to a given level. This study also shows the hybrid system is superior to both active and passive …

Biological Fixed-Film Systems, Mark W. Fitch, Natalie Pearson, Gene Richards, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Contribution Of Externally Bonded Frp To Shear Capacity Of Rc Flexural Members, Ahmed Khalifa, William J. Gold, Antonio Nanni, M. I. Abdel Aziz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber reinforced polymer (FRP) materials are continuing to show great promise for use in strengthening reinforced concrete structures. These materials are an excellent option for use as external reinforcing because of their light weight, resistance to corrosion, and high strength. Externally bonded FRP sheets have been used to increase moment capacity of flexural members and to improve confinement in compression members. Investigations into the use of externally bonded FRP sheets for shear strengthening have also been conducted and have been shown to be viable. The objectives of this study were to review the current research on shear strengthening with FRP …