Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 10651 - 10680 of 11944

Full-Text Articles in Entire DC Network

Modeling Three-Dimensional Groundwater Flow And Solute Transport By The Finite Element Method With Parameter Estimation., Fang Xin Yu Jan 1992

Modeling Three-Dimensional Groundwater Flow And Solute Transport By The Finite Element Method With Parameter Estimation., Fang Xin Yu

LSU Historical Dissertations and Theses

A general, systematic and improved numerical formulation for the three-dimensional (3-D) groundwater flow and solute transport problems was derived, using the finite element method. In the numerical formulation, a hidden mistake, which has appeared in many textbooks and journal papers dealing with the advective term of the general 3-D solute transport equation, was found and corrected. Some simpler and practical expressions for the leaky boundary condition, surface flux condition, and sources and sinks were proposed. To improve the conventional formulation for the time derivatives, a combination of the Galerkin method and the collocation method was developed. A more accurate scheme …

Go to article

Plasticity-Damage Bounding Surface Model For Concrete Under Cyclic-Multiaxial Loading., Taher Mowafaq Abu-Lebdeh Jan 1992

Plasticity-Damage Bounding Surface Model For Concrete Under Cyclic-Multiaxial Loading., Taher Mowafaq Abu-Lebdeh

LSU Historical Dissertations and Theses

Concrete exhibits a significant strain-softening behavior beyond the peak stress, and moreover, the mechanism of inelastic deformation in concrete consists of both plastic slip and microcracking. Hence, a combined plasticity and damage mechanics model is proposed for modeling concrete behavior under both multiaxial monotonic and cyclic loadings. The model adopts a bounding surface concept for both plasticity and damage. The introduced plasticity bounding surface is a function of the maximum compressive strain experience by the material, while the damage bounding surface is a function of the accumulated damage parameter. By this definition, both surfaces shrink in size in the stress …

Go to article

The Use Of Hydrologically Altered Wetlands To Treat Wastewater In Coastal Louisiana., Andree Marie Breaux Jan 1992

The Use Of Hydrologically Altered Wetlands To Treat Wastewater In Coastal Louisiana., Andree Marie Breaux

LSU Historical Dissertations and Theses

Two major environmental problems currently affecting Louisiana are a high rate of coastal wetland loss and high levels of surface water pollution. The application of secondarily treated wastewater to wetlands is proposed as a means of dealing with these problems. The benefits of wetland wastewater treatment include improved surface water quality, increased accretion rates to balance subsidence, improved plant productivity, and decreased capital outlays for conventional engineering treatment systems. Wetland treatment systems can be designed and operated to restore deteriorating wetlands to previous levels of productivity. Hydrologically altered wetlands in the Louisiana coastal zone have been selected as appropriate for …

Go to article

Nonlinear Stochastic Modeling Of Daily Temperature Series., Glenn Poloyapoy Fernandez Jan 1992

Nonlinear Stochastic Modeling Of Daily Temperature Series., Glenn Poloyapoy Fernandez

LSU Historical Dissertations and Theses

The major objective of this research is to develop daily time series models for maximum and minimum temperature series. A generalized modeling methodology is presented. Stochastic modeling was accomplished by analyzing the structural characteristics of the temperature series. Analyses included assessment for time reversibility, linearity, structural dependence and distributional properties of the weakly stationary series obtained by parametric standardization of the observed series. Based on the results of the structural characterization of the series and the results of the model class identification using a 'state-dependent model' formulation, a bilinear model class was identified as appropriate for the temperature series. Various …

Go to article

Modernity And War In The Poetry Of T. S. Eliot., Patricia Anne Gabilondo Jan 1992

Modernity And War In The Poetry Of T. S. Eliot., Patricia Anne Gabilondo

LSU Historical Dissertations and Theses

Although most readers of T. S. Eliot have agreed that the European experience of world war and the resultant political and cultural dislocations provided an important context and source of imagery for much of his work, what has not been recognized is Eliot's use of figures of war to represent the intimate yet antagonistic relations between the poet's writing of modernity and the text that is history. Beginning with a tropological analysis of Eliot's "A Note on War Poetry," relative to both the genre of war poetry and aesthetic modernity, this study examines the figural interpenetration of war and literary …

Go to article

Identification Of Plant Science Concepts Needed In Agriscience Programs Of The Future., Camile Patrick Gaspard Jan 1992

Identification Of Plant Science Concepts Needed In Agriscience Programs Of The Future., Camile Patrick Gaspard

LSU Historical Dissertations and Theses

The purpose of this study was to identify the plant science concepts which should be taught in secondary agriculture programs of the future as perceived by innovators in the field of plant science. The Delphi technique was used to gain the perceptions of a nation-wide panel of plant science professionals. The panel was comprised of three groups of plant scientists: secondary plant science teachers, university plant scientists, and plant scientists working in industry. The secondary plant science teachers were selected from the national and regional winners of the agriscience teacher award. The university plant scientists and plant scientists working in …

Go to article

Demonstration Of A Control Strategy For Sustained Algal Growth At A Full-Scale Level Under Computer-Automated, Continuous Culture Conditions., Kelly Ann Rusch Jan 1992

Demonstration Of A Control Strategy For Sustained Algal Growth At A Full-Scale Level Under Computer-Automated, Continuous Culture Conditions., Kelly Ann Rusch

LSU Historical Dissertations and Theses

A computerized algal turbidostat was designed and constructed for use in aquaculture facilities requiring a continuous feed source. Continuous cultures, maintained in the exponential growth phase by the continual introduction of fresh media, exhibit a steadystate nature easily adaptable to computer automation and optimization processes. These characteristics, in contrast to batch culture methods, result in both reduced land and labor requirements; an important consideration for commercial applications wherein algal production occupies as much as 40 percent of a facility in both space and cost. The turbidostat system consisted of two 0.6 m$\sp3$ growth chambers supported by a central monitoring block …

Go to article

Modification Of The Drainmod-Creams Model To Incorporate A Nutrient Submodel., Abdul Razak Bin Saleh Jan 1992

Modification Of The Drainmod-Creams Model To Incorporate A Nutrient Submodel., Abdul Razak Bin Saleh

LSU Historical Dissertations and Theses

DRAINMOD-CREAMS model was used to simulate surface runoff and sediment loss from subsurface drained plot and non-subsurface drained plot in southern Louisiana. Seven years (1981-1987) of recorded data were used in this study. In general, the performance of the model in simulating surface runoff and sediment loss from subsurface drained plot is satisfactory. However, the DRAINMOD-CREAMS model did not simulate surface runoff and sediment loss accurately from non-subsurface drained plot. The CREAMS nutrient submodel was also tested on both plots. The CREAMS model seriously overestimates the nitrogen loss from non-subsurface drained plot. The sensitivity of the DRAINMOD-CREAMS model on erodibility …

Go to article

Physiology And Biochemistry Of A Lignin-Degrading Bacterium Erwinia Sp. Cu 3614., Janardhanan S. Rajan Jan 1992

Physiology And Biochemistry Of A Lignin-Degrading Bacterium Erwinia Sp. Cu 3614., Janardhanan S. Rajan

LSU Historical Dissertations and Theses

Previous researchers have reported the isolation of a diphenylether cleaving organism, Erwinia sp., using an enrichment medium containing lignin. A copper and dinitrophenol resistant mutant of this organism, Erwinia sp. Cu3614, has also been reported. To assess the effect of copper on the growth and biochemistry of this organism, continuous cultivation was used employing an apparently optimized medium containing ethanol as carbon source. Upon increasing the concentration of copper sulfate in the medium from 5 $\mu$g/ml to 10 $\mu$g/ml increases in maximum specific growth rate and growth yield were seen. Also decrease in the values for doubling time and the …

Go to article

A Regional Market Model For Construction Aggregate Materials., Alicia Norma Rambaldi Jan 1992

A Regional Market Model For Construction Aggregate Materials., Alicia Norma Rambaldi

LSU Historical Dissertations and Theses

The primary objective of this dissertation is to model the regional markets for traditional construction aggregates, sand, gravel, and crushed stone. The long-term dynamics of the construction industry related to the demand for aggregates is modeled through a partial adjustment mechanism. The dynamics of the construction industry is introduced into the estimation of a simultaneous equations model of the demand and supply for aggregates at district levels. An engineering-based cost function for extraction of sand and gravel is estimated based on data collected from an operator's survey in the states of Alabama, Arkansas, Louisiana, Mississippi, and Texas. A step-supply for …

Go to article

Developing A Research Agenda For The Louisiana Cooperative Extension Service., Fred S. Sanders Jr Jan 1992

Developing A Research Agenda For The Louisiana Cooperative Extension Service., Fred S. Sanders Jr

LSU Historical Dissertations and Theses

The primary purpose of this study was to determine potential future research priorities for the Louisiana Cooperative Extension Service. The Delphi method of forecasting was determined to be the most appropriate for use in this study. Having a knowledge of, and a current relationship with, the Louisiana Cooperative Extension Service (LCES) was the initial criteria for selecting panelists for this study. The final panel consisted of forty LCES personnel. Three rounds of questionnaires were used in this study. The Round 0 questionnaire was open-ended and was used to generate a list of perceived research items most in need of research …

Go to article

The Effect Of Instructional Videos And Simulation-Gaming Activities In The Environmental Science Curriculum On Knowledge And Attitudes., Lyle Mark Soniat Jan 1992

The Effect Of Instructional Videos And Simulation-Gaming Activities In The Environmental Science Curriculum On Knowledge And Attitudes., Lyle Mark Soniat

LSU Historical Dissertations and Theses

As a result of science reform efforts in the United States numerous shortcomings of the predominant curricula have been identified. The following study evaluates a modular, environmental science curriculum entitled Wild Louisiana, which attempts to address these shortcomings. Wild Louisiana is Science-Technology-Society (STS) oriented and infuses regionally based instructional videos and simulation-gaming activities into the secondary science curriculum. The videos and activities depict the confluence of regional biological, technical, and social phenomena to illustrate universal environmental concepts. The multimedia, modular approach is intended to address the varied learning styles of different students. Following random selection, teachers were randomly assigned to …

Go to article

Organic-Rich Lower Tertiary Shales, South Louisiana: Implications For Petroleum Source Rock Deposition., Elizabeth Wyatt Chinn Mcdade Jan 1992

Organic-Rich Lower Tertiary Shales, South Louisiana: Implications For Petroleum Source Rock Deposition., Elizabeth Wyatt Chinn Mcdade

LSU Historical Dissertations and Theses

This study presents comprehensive organic geochemical evidence of organic-rich marine shales in the middle Eocene lower part of the Claiborne Group and the lower Eocene-Paleocene Wilcox Group of south Louisiana. The shales are the only post-Cretaceous age sediments in the northwest Gulf of Mexico basin that fit the conventional criteria for liquid hydrocarbon source rocks. Visual and geochemical evidence suggests that the Paleogene shales contain terrestrially derived, amorphous kerogen with high hydrogen indices whose oil potential has been upgraded by bacterial degradation. The Paleogene section is at immature to late mature levels with respect to petroleum generation, at present-day burial …

Go to article

Three-Dimensional Nonlinear Analysis Of Components Of Reinforced Concrete Framed Structures., Srinivas Maddipudi Jan 1992

Three-Dimensional Nonlinear Analysis Of Components Of Reinforced Concrete Framed Structures., Srinivas Maddipudi

LSU Historical Dissertations and Theses

This study deals with the three dimensional analysis of reinforced concrete structural members under multiaxial loading conditions. An incremental formulation in conjunction with the finite element method is used to simulate the behavior of reinforced concrete material. A hypoelastic model capable of simulating response of plain concrete under nonproportional loading conditions is employed. A five parameter strength envelope is used to predict the failure of concrete in multiaxial stress states. A smeared crack model capable of handling multiple non-orthogonal cracks is used to represent the post cracking behavior of concrete. Objectivity in the results of analysis utilizing the smeared cracking …

Go to article

Assimilation Of Organic Contaminants In Wetlands: Processes And A Conceptual Model., John Howard Pardue Jan 1992

Assimilation Of Organic Contaminants In Wetlands: Processes And A Conceptual Model., John Howard Pardue

LSU Historical Dissertations and Theses

Laboratory studies and field measurements were conducted to quantify assimilative capacity of toxic organic contaminants in freshwater wetlands. Studies were conducted for hexachlorobenzene and naphthalene in a mineral-dominated bottomland hardwood forest and an organic matter-dominated freshwater marsh. In laboratory studies, sorption of hexachlorobenzene (HCB) in wetland soil and floodwater was strongly influenced by high levels of naturally occurring dissolved organic carbon (DOC). Organic matter-dominated wetlands (e.g., marshes) demonstrated no advantage over mineral-dominated wetlands (e.g., bottomland hardwood forests) for sorption of HCB due to partitioning in this DOC phase. Over the short-term, sorption of HCB was adequately described using a three-phase …

Go to article

Jeremy Rifkin Challenges Recombinant Dna Research: A Rhetoric Of Heresy., Wiley Michael Futrell Jan 1992

Jeremy Rifkin Challenges Recombinant Dna Research: A Rhetoric Of Heresy., Wiley Michael Futrell

LSU Historical Dissertations and Theses

Western culture, in large part, is a product of scientific inquiry, technological development and the ability to harness some of nature's resources. Much of society looks to science for technology-related solutions to many of its ills. As it develops new technology, science necessarily seeks to understand and control the forces of nature. Although science assumes a prominent role in contemporary society, that prominence does not necessarily translate into cultural consensus on the progress achieved by technological developments. Another perspective is represented by those who contend that continued technological advancement is the source of existing problems, not the solution. As these …

Go to article

Dynamic Response Of An Electron Storage Ring Magnet., Shahriar Jahanian Jan 1992

Dynamic Response Of An Electron Storage Ring Magnet., Shahriar Jahanian

LSU Historical Dissertations and Theses

A combined experimental and numerical methodology was employed to investigate the dynamic response of the electron storage ring dipole magnets located in the Center for Advanced Microstructural Devices (CAMD) at Louisiana State University (L.S.U.). The magnet are highly anisotropic and can not be analysed for dynamic response without knowledge of the effective elastic properties. The theory of wave propagation in conjunction with finite element analysis was used to determine the variation of the effective modulus of elasticity magnets in question. The structure of the magnet was modeled with NASTRAN. A theoretical analysis was performede that supported the experimental variation of …

Go to article

The Role Of Affect In Service Encounter Satisfaction: An Experimental Study., Rama Kumari Jayanti Jan 1992

The Role Of Affect In Service Encounter Satisfaction: An Experimental Study., Rama Kumari Jayanti

LSU Historical Dissertations and Theses

The objective of the dissertation was to address the influence of affect towards service provider on service encounter satisfaction. The following research questions were examined: (1) the impact of affect towards the service provider on perceived performance and satisfaction; (2) the relative influence of affective versus cognitive variables in explaining satisfaction with services; (3) the explanatory ability of the disconfirmation model of satisfaction within the context of services. An experimental study was designed to address the above questions. Two factors, affect towards the service provider labeled Evaluative Impression of the service provider and Interaction Style (one dimension of perceived performance) …

Go to article

A Formal Methodology For The Specification Of Distributed Systems From An Object Perspective., Sangbum Lee Jan 1992

A Formal Methodology For The Specification Of Distributed Systems From An Object Perspective., Sangbum Lee

LSU Historical Dissertations and Theses

Distributed computing systems are systems in which multiple processors run independently by communicating with each other. The design of distributed systems is difficult to achieve as the execution patterns of distributed system are typically more complex than those of non-distributed computing systems. The application of object-oriented techniques to the design of distributed systems has the potential to increase the power of modeling and computing. A formal methodology which includes a specification language, developed from an object perspective, for the development of distributed systems is presented. The formal specification language, DOSL (Distributed Object-based Specification Language), represents the specification of distributed systems …

Go to article

A Study Of Selected Phenomena Observed During Rotary Kiln Incineration., Christopher Brian Leger Jan 1992

A Study Of Selected Phenomena Observed During Rotary Kiln Incineration., Christopher Brian Leger

LSU Historical Dissertations and Theses

A comprehensive research program is underway at LSU with the ultimate goal of improved understanding and predictive capability for the performance of rotary kiln incinerators. In an extensive experimental study, packs containing toluene-contaminated clay sorbent are batch-fed into the field-scale rotary kiln incinerator of the Louisiana Division of Dow Chemical USA. Water cooled probes are used to obtain continuously gas temperatures and species concentrations within the kiln and afterburner, and existing facility instruments are also monitored. The kiln rotation rate is varied and turbulence air (air injected into the kiln to improve mixing) is added or turned off. Conditions at …

Go to article

Consumer Evaluation Of Product-Related Injuries: The Development And Empirical Testing Of A Behavioral Model Of The Product Liability Process., Bryce Mitchell Griffin Jan 1992

Consumer Evaluation Of Product-Related Injuries: The Development And Empirical Testing Of A Behavioral Model Of The Product Liability Process., Bryce Mitchell Griffin

LSU Historical Dissertations and Theses

This study strives to provide a better understanding of consumer evaluation of product liability cases. A model of consumer perceptions of the liability process, based predominantly on attribution theory, is developed and tested. The research first develops a general attributional model of the liability process, identifies relevant managerially-controllable dimensions of liability cases, and then tests consumer reaction to these factors utilizing experimental scenarios. The influence of several consumer-juror individual difference variables on the evaluation of liability cases is examined. In addition, potential mediators of the product liability process, including assessment of responsibility and affective evaluation of the plaintiff and defendant, …

Go to article

Incorporating Reservoir Characteristics For Automatic History Matching., Keith J. Halford Jan 1992

Incorporating Reservoir Characteristics For Automatic History Matching., Keith J. Halford

LSU Historical Dissertations and Theses

Automatic history matching is refined in this work by expanding the objective function and incorporating reservoir characteristics in the process of parameter selection. Iso-value contours are used to incorporate reservoir characteristics within history-matching parameters. These improvements are implemented in an automatic history-matching algorithm, OPTIM, that is coupled with BOAST II. Case histories of both hypothetical and real reservoirs demonstrated the effectiveness of incorporating reservoir characteristics in automatic history-matching parameters.

Go to article

Recovery Of Sugars From Cane Molasses By Continuous Simulated Moving Bed Ion-Exclusion Chromatography., Khalid Iqbal Jan 1992

Recovery Of Sugars From Cane Molasses By Continuous Simulated Moving Bed Ion-Exclusion Chromatography., Khalid Iqbal

LSU Historical Dissertations and Theses

Present investigation was undertaken to determine the feasibility of using a Simulated Moving Bed (SMB) Ion Exclusion Chromatographic system for the recovery of sugars from molasses. The recovery of sugars from molasses is complicated because of the presence of high concentration of salts of K, Ca, Mg, etc. The presence of these salts in the molasses prevents sucrose to crystallize. SMB Ion Exclusion Chromatography has been shown to be successful to recover sugars from beet molasses, and to separate sugars from each other in High Fructose Corn Syrup industry. The basis of the ion exclusion is that the sorbent used …

Go to article

Interactive Graphics-Based Musculotendon Modeling For Reconstructive Surgery Of The Hand., Inmo Yoon Jan 1992

Interactive Graphics-Based Musculotendon Modeling For Reconstructive Surgery Of The Hand., Inmo Yoon

LSU Historical Dissertations and Theses

This research has been directed at studying and developing a prototype research and clinical Computer Aided Design (CAD) tool to be used for planning tendon paths in hand reconstructive surgery. Of equal importance is the goal of having an educational tool for teaching hand biomechanics to students of this specialty. The application of CAD to rehabilitative surgery of the hand is a new field of endeavor. There are currently no existing commercial products designed to assist the orthopedic surgeon in planning these complex procedures. Additionally, orthopedic surgeons are not trained in mechanics, kinematics, math modeling, or the use of computers. …

Go to article

The Stability Of Thick, Self-Gravitating Disks In Protostellar Systems., John William Woodward Jan 1992

The Stability Of Thick, Self-Gravitating Disks In Protostellar Systems., John William Woodward

LSU Historical Dissertations and Theses

We perform a computational survey of the stability of protostellar systems which contain a self-gravitating disk. The systems are initially represented by a point mass $M\sb{c}$ at the center and a geometrically thick, axisymmetric disk of mass $M\sb{d}$ that supports uniform specific angular momentum and obeys an n = 3/2, polytropic equation of state. The equilibrium disk structure is uniquely defined upon the specification of two key dimensionless system parameters: $M\sb{d}/M\sb{c}$ and $T/\vert W\vert$ (the ratio of rotational kinetic energy of the disk to the gravitational potential energy of the system). The focus of this work is the identification of …

Go to article

The Purification Of Mcrb And Mcrc Proteins In Mcrbc Restriction System Of Escherichia Coli K12 And Dna Sequencing Of The Region Downstream Of Mcrc., Ling Zheng Jan 1992

The Purification Of Mcrb And Mcrc Proteins In Mcrbc Restriction System Of Escherichia Coli K12 And Dna Sequencing Of The Region Downstream Of Mcrc., Ling Zheng

LSU Historical Dissertations and Theses

The McrBC restriction system of Escherichia coli K12 degrades methylcytosine-containing foreign DNA. Two genes mcrB and mcrC had been shown to be required for the McrBC restriction (Ross, et al., J. Bacteriol., 1989b). To explore the involvement of additional gene(s), a 1.7 kb fragment downstream of the mcrC was cloned and sequenced. Also mutants containing deletion in mcrBC or the downstream region were isolated by transposon excision. Genetic complementation studies confirmed that only DNA containing mcrB and mcrC gene on a high copy plasmid were needed to fully restored McrBC restriction. Deletion of the 1.7 kb fragment from or addition …

Go to article

Precision Cultural Practices For Commercial Vegetable Production, Richard L. Parish Jan 1992

Precision Cultural Practices For Commercial Vegetable Production, Richard L. Parish

LSU Agricultural Experiment Station Reports

No abstract provided.

Go to article

Effects Of Hydrologic Alterations On The Vegetation And Soils Of Marshes In Southern Louisiana., Kathryn Marie Flynn Jan 1992

Effects Of Hydrologic Alterations On The Vegetation And Soils Of Marshes In Southern Louisiana., Kathryn Marie Flynn

LSU Historical Dissertations and Theses

Hydrology is the primary forcing function in wetlands. Therefore, alterations to hydrology, which can result from either natural or anthropogenic causes, can have dramatic effects on wetland structure and function. Structural marsh management, one type of anthropogenic alteration, employs levees and water control structures to reduce or reverse wetland loss and enhance the productivity of natural renewable resources. Its use is becoming increasingly popular in southern Louisiana as a solution to the problem of marsh deterioration despite the fact that very line comprehensive data is available on the effectiveness of this practice. Associated with the use of structural marsh management …

Go to article

Soot Suppressing Mechanisms Of Iron In Premixed Hydrocarbon Flames., David Worthington Hahn Jan 1992

Soot Suppressing Mechanisms Of Iron In Premixed Hydrocarbon Flames., David Worthington Hahn

LSU Historical Dissertations and Theses

In-situ light scattering measurements are combined with chemical analysis of sampled soot particles to elucidate the mechanisms through which iron addition affects soot formation and growth processes in fuel-rich, premixed propane and oxygen flames. Soot particle optical inhomogeneity resulting from the addition of iron is accounted for in the light scattering analysis using an effective refractive index model. The influence of iron addition on soot particle diameters, number densities, volume fractions, surface areas, and specific growth rates is investigated. In addition, X-ray photoelectron spectroscopy was used to determine the chemical state of iron species throughout the flame. The analysis revealed …

Go to article

Development Of A Portable And Selective Volatile Organic Compound Analyzer Based On An Enhanced Microchip Gas Chromatograph., Aaron Meleki Mainga Jan 1992

Development Of A Portable And Selective Volatile Organic Compound Analyzer Based On An Enhanced Microchip Gas Chromatograph., Aaron Meleki Mainga

LSU Historical Dissertations and Theses

Although the use of portable gas chromatographs is a well established technique, it is still experiencing rapid growth. For continued growth and acceptance, however, it must be a viable alternative over the use of traditional gas chromatographs, in terms of its applicability for identification of important compounds, and its routine use for the analysis of volatile organic compounds (voc) in ambient air. The biggest limitation to the use of portable gas chromatographs is their lack of sensitivity to low concentrations of voc's. Most portable gas chromatographs at present have a detection limit of about 1 ppmv, while the concentration of …

Go to article

First Prev Next Last