Digital Commons Network^™

Resource Use Rates: Estimation Of Time Invariant Decision Rules (Erosion), Douglas John Lawrence

Doctoral Dissertations

As interest in soil conservation has increased, understanding the soil management decision rule used by farmers has become more important. The model developed to analyze the optimal decision rule for soil use rates is essentially a supply response model which assumes rational expectations. It can be characterized as a dynamic optimal control model with feedback from decisions to states. Three Stage Least Squares estimation is re-interpreted to fit the requirements of rational expectations. The estimated coefficients suggest that soil conservation policy must consider general economic variables as well as traditional variables such as soil depth and cost sharing to be …

Higher Education And Life Chances: A Study Of Occupational Attainments And Attitudes Among Some Public University Graduates, Richard Peter Talbot

Doctoral Dissertations

This study investigates the post-graduate educational and occupational experiences of the 1968 and 1978 graduates of a state flagship university. First, it explores the influence of parental variables upon respondents' choice of curriculum and of post-graduate study. Second, it examines the occupational placement of the respondents by cohort and by gender. Third, it explores the present attitudes of the respondents by cohort and gender.

A stratified random sampling of the graduates (N = 433) via a mailed survey questionnaire shows that more men than women in the 1968 cohort return their forms. There is the suspicion that only those who …

Town And Province In Revolutionary New Hampshire: A Stable Political Culture Confronts Change, 1765--1776, Marilyn Mulzer Robbert

Doctoral Dissertations

The study analyzes the relationship of the towns to the provincial government between 1765 and 1776 to understand the underlying process of the coming of the Revolution in New Hampshire. The focus is on the towns, and the main sources are unpublished town records.

For one part of the study, I developed a system to identify legislative leaders (a modification of Jack Greene's method), used Gini scores to compare the General Assemblies with the Provincial Congresses and the 1776 House of Representatives, and constructed a composite biography for the 296 men who served during the period.

A comparison of the …

The Ronson Ship: The Study Of An Eighteenth-Century Merchantman Excavated In Manhattan, New York In 1982, Warren Curtis Riess

Doctoral Dissertations

During a pre-construction archaeological investigation at 175 Water Street, Manhattan, New York in 1982, excavators discovered an eighteenth-century merchant ship. The port side of the ship was excavated and recorded and the bow was taken apart and saved. Since that time historical and archaeological studies have been conducted to interpret the site to glean information about eighteenth-century technology and economics. The remains of this ship are particularly important because no draft or other remains of early eighteenth-century transatlantic merchantmen have been discovered.

The ship appears to be a Virginia-built ship which sailed between the Chesapeake and England or Scotland carrying …

Body Tensor Formalism In Finite Deformation Elasticity And Application To The Torsion Of A Circular Cylinder, Alexander Sachs

Doctoral Dissertations

In this work one develops the body tensor formalism for homogenous, isotropic elastic materials. This formalism is general and not limited to small deformations. One examines the physical laws and the constitutive equation which relates the stress to the strain with the help of the two Lame coefficients and the three third order elastic constants. Although the body tensor formalism has been used before to describe finite deformation elasticity, it has not been used to generalize the constitutive equation for the stress-strain relationship.

The body tensor formalism and the generalised constitutive equation are applied to the torsion of a right …

Simplified Analysis Of A Cladding-Frame Structural System, Nancy Marie Alberto

Doctoral Dissertations

This dissertation presents a simplified approach for the preliminary design and static analysis of a cladding-frame structural system subjected to concentrated, lateral loading conditions. The simplified approach, which utilizes the finite element analysis method, reduces the number of computations required for analysis of a structurally cladded frame to that of an architecturally cladded frame. This research develops a modified beam element to analytically replace a cladding panel element while retaining its structural benefits. The modified beam element is derived using a 16 degree of freedom isoparametric element and displacement correlations determined from the studies of a two-story, single bay frame …

Sources Of Stress In Middle Childhood: Child And Parent Perspectives, Maryann Collins Corsello

Doctoral Dissertations

Much of the literature on childhood stress is based on adult assumptions of what is stressful to children. Rarely are young children solicited for their perspective. The present study addressed the following two issues in the assessment of childhood stress: (1) Can young children give reliable and valid appraisals of potentially stressful situations? (2) Do these appraisals differ systematically from those made by parents for their children?

In small group discussions, children in grades 1 through 4 (N = 62) provided information on sources of stress and pictures of a "nervous" person. The child-provided stressors and the drawings formed the …

Development Of Design Criteria For Ferritic Stainless Steel Cold-Formed Structural Members And Connections, Pieter Van Der Merwe

Doctoral Dissertations

"This dissertation describes the development of the basic criteria needed for the design of structural members cold-formed from certain ferritic stainless steels. The Allowable Stress Design method as well as the Load and Resistance Factor Design method receive attention. The ferritic stainless steels under consideration are: Types AISI 409 and 430 as well as a modified Type 409 steel, designated 3CR12 steel, developed and produced by the speciality steel producing company, Middelburg Steel and Alloys in South Africa.

The mechanical properties needed for structural design are established. It is shown through an experimental study that the design provisions for the …

Bubble Formation, Movement And Distortion In Viscous Glass, Simon Cheng-Ping Wang

Doctoral Dissertations

"A study of bubble formation, movement and distortion in viscous glass is described. A glass rod containing an irregularly shaped hole is heated to a temperature at where the glass viscosity is low enough to let the hole form a spherical bubble. Spheration occurs as the bubble moves upward in the glass rod. At the proper time, the rising bubble is decelerated and brought to a stop by increasing the glass viscosity by slowly reducing the temperature. The entrapped bubble is then cut from the glass rod and heated again, if necessary, to a lower temperature, to reduce distortion of …

Effects Of The Luminous Environment On Managerial Decision Making, Marc Clay Belcher

Doctoral Dissertations

"Little is known about the influence the physical environment may have on the way a manager goes about making decisions. This work considers one element of the environment, lighting, and attempts to establish a relationship between that element and the decision strategy a manager may select.

From a review of the literature on the effects of light on man and from the field of decision making, a model is posited suggesting that the luminous environment affects decision making. Since others have established that mood influences how decisions are made, and since it is suggested in the literature that lighting affects …

Fundamental Study Of The Role Of Cathode Structure On Zinc Electrowinning, Horacio M. Aros

Doctoral Dissertations

"The influence of cathode macromorphology on the current efficiency of zinc electrowinning was determined.

The studies have shown that surface roughness affects current efficiency during zinc electrowinning, particularly when the electrolyte contains impurities such as nickel and antimony. Current efficiency does not change with surface roughness as long as the electrolyte is sufficiently pure.

Zinc deposited on smooth zinc cathodes tends to retain a more favorable structure and macromorphology, which is less sensitive to the effects caused by antimony and nickel. Glue helps to counteract the effect of the impurities; however, its presence in the electrolyte at certain combinations with …

Structural Behavior Of Members Consisting Of Flat And Curved Elements, M. Brad Parks

Doctoral Dissertations

"Local buckling of stiffened and unstiffened curved elements has been investigated both experimentally and analytically. Stiffened curved elements are supported on all four edges while unstiffened curved elements are supported along three edges with one longitudinal edge free.

A series of stub column, beam, and shear tests have been performed for sections containing curved elements. The tested specimens were formed from sheet steels with yield strengths ranging from 27 to 88 ksi. The radius-to-thickness, R/t, values of the curved elements varied from 12 to 438 whereas the arc length-to-thickness, bit, ratios ranged from 23 to 218.

As a result of …

Experimental Vapor-Liquid Equilibria Of Propyne With Propane, Propene And Propadiene, Edward Allen Kyser

Doctoral Dissertations

"Vapor pressures for pure propane, pure propene, impure propadiene and pure propyne and 19 binary mixtures of propane, propene, and propadiene with propyne are reported at -20, 5, 30, 55 and 80° C. An equation of state utilizing pure component saturated vapor and liquid densities is used to correlate all the data and the effect of the propadiene impurities was theoretically removed. The data of Burcham (1981) are recorrelated using new information about the impurities, and different results are obtained. Calculated relative volatilities and saturated densities are reported for the systems propane-propyne, propene-propyne, propadiene-propyne and propane-propadiene"-- Abstract, p. ii

Phase Equilibria From Pvt Measurements For Carbon Dioxide, Water And N-Decane, Michael Nduka Okafor

Doctoral Dissertations

"Phase equilibrium properties for the carbon dioxide - water - n-decane system were determined from pressure-temperature-volume (PVT) measurements. PVT properties were also obtained for pure carbon dioxide and water, and the binary mixtures of carbon dioxide - water and carbon dioxide - n-decane. The experiments were conducted at temperatures of 313.17, 353.15 and 393.15 Kelvin, and at pressures from 37 to 416 bar. Measurements for the mixtures were terminated when complete miscibility was observed.

The Perturbed-Hard-Chain (PHC) equation of state developed by Gmehling et al. (1979) was chosen to correlate the measured data because of its ability to handle the …

Studies Of Defect Structure And Oxidation-Reduction Behavior Of Undoped Lamno₃, Sr-Doped Lamno₃ And Mg-Doped Lamno₃, Jen-Ho Kuo

Doctoral Dissertations

"Undoped LaMnO₃, Sr-doped LaMnO₃ and Mg-doped LaMnO₃ showed reversible oxidation-reduction behavior. These perovskites can be excess, stoichiometric or deficient in oxygen content depending on the specific conditions. Under very reducing conditions these oxides will decompose into new phases. Phase stabilities for these oxides were determined. The results showed that both Sr and Mg doping caused the LaMnO₃ to dissociate at higher oxygen activities than for undoped LaMnO₃.

Defect models were proposed to interpret the TG results, in which metal vacancies are assumed for the oxygen excess condition and oxygen vacancies are assumed for the oxygen deficient condition. Thermodynamic properties were …

The Effect Of Rain On Intertidal Estuarine Sediment Transport (Vortex Rings, Oxygenation, Drop/Splash Features, Fecal Pellets), Thomas Cortland Shevenell

Doctoral Dissertations

Storms are important aperiodic events, which intensify erosional processes over short time periods. The effect of rain on the shallow intertidal water column was the focus of this study. The literature was extensively reviewed to identify parallel research in other scientific disciplines, which could be used to understand how raindrops may be acting as a sediment resuspension mechanism. Single-drop and multi-drop laboratory studies were conducted on the initiation of motion of sediment. Results indicate single vortex rings in a quiescent environment can initiate motion of sand-sized noncohesive sediment in all water depths tested, up to and including 22.5 cm. Multidrop …

Analysis And Simulation Of The Pneumatic Braking System Of Freight Trains, Khaled Sayed Abdol-Hamid

Doctoral Dissertations

In North America, and in many other parts of the world, freight trains still employ pneumatic equipment for braking. The 26C locomotive valve and control valves of the cars are connected by a brake pipe which serves the dual purpose of conducting pneumatic power and transmitting the control signal (brake signal) from the locomotive to each car of the train. The development of the air brake system has been largely empirical and experimental, which may take years to develop a new design.

In this thesis, a new brake pipe mathematical model is developed, including the interaction of the branch pipe. …

An Investigation Of Aquatic Macrophyte-Based Aquatic Wastewater Treatment Systems For Temperate Climates (Elodea Nuttallii, Photosynthesis, Nutrient Budget, Active Transport, Nitrification), Thomas Taylor Eighmy

Doctoral Dissertations

Aquatic treatment systems are a low cost, low energy alternative to conventional treatment systems; they can provide secondary and advanced secondary wastewater treatment capabilities for small communities. Their potential application in temperate climates has been ignored. The research presented here was conducted to examine their applicability for use in temperate regions. A pilot-scale aquatic macrophyte-based aquatic treatment system was designed to treat primary effluent. Four aquatic macrophytes (Elodea nuttallii, Lemna minor, Myriophyllum heterophyllum, Ceratophyllum demersum) were evaluated as candidates. The hydraulic, organic, and nutrient loadings to the reactors were similar to design values for water hyacinth (Eichornia crassipes) systems. Nitrification …

The Role Of Error Analysis, Diagnostic Grading Procedures, And Student Reflection In First Semester Calculus Learning (Epistemology, Metacognition, Inquiry), Karen Jean Geuther

Doctoral Dissertations

The present study is an integrative study designed to explore the nature of student difficulties within the context of a first semester college calculus course. The techniques of error analysis were used to identify and categorize the student difficulties. Insights gained from this categorization served as the basis for the design and development of calculus grader preparation materials implemented with a subgroup of undergraduate calculus graders. These grader preparation materials emphasized grader diagnosis of student difficulties and student reflection on errors and process. Current preparation procedures served as the control on the basis of which comparisons and evaluations were made. …

Fire Resistance Of Concrete-Filled And Reinforced Concrete Columns, Mohamed El-Shayeb

Doctoral Dissertations

In order to calculate the fire resistance of a building component, it is necessary to know the temperature history of the component during exposure to fire. In this dissertation a numerical method is described for calculating the temperature field in fire-exposed columns. The procedure is based on a finite difference method for calculating the temperature history of concrete-filled square steel and cylindrical reinforced concrete columns. Two mathematical models and their related computer programs for these columns are presented in this dissertation.

Furthermore, the Division of Building Research of the National Research Council of Canada, is now carrying out extensive experimental …

Web Crippling Of High Strength Cold-Formed Steel Beams, Chiravut Santaputra

Doctoral Dissertations

"The structural behavior of high strength cold-formed steel beams subjected primarily to web crippling was investigated analytically and experimentally. In this study hat sections and I-beams, formed from five different types of high strength sheet steels commonly used in the automobile industry, were investigated under various loading conditions. The yield strengths of these sheet steels vary from 58 to 165 ksi.

In addition to the test data gathered in this phase of study, the experimental results obtained from the beam tests conducted at Inland Steel Company and Ford Motor Company were carefully evaluated. The evaluation indicated that the present available …

A Semantic Basis For Parallel Algorithm Design, Roger E. Eggen

Doctoral Dissertations

"As computing demands increase, emphasis is being placed on parallel architectures- To efficiently use parallel machines, software must be designed to take advantage of these machines. This research concentrates on an abstraction of algorithm design to permit the expression of parallel programs. The abstraction emphasizes thought about algorithms at a high level as opposed to algorithm implementation at a statement level. A model based on data flow allows algorithm expression using flow diagrams. The model specifies operating system requirements that support parallel programming at a module level. Paths are used to carry data between modules. Data enter modules through ports. …

An Investigation Of Signs For Median Crossovers, Gillian M. Worsey

Doctoral Dissertations

“This paper describes a study of advance warning signs for median crossovers on divided highways. Candidate crossover signs were identified from a literature review, survey of current State practices and discussions with FHWA personnel. Seven of these signs were selected for further testing in a laboratory study for legibility, understanding and driver preference. Sixty subjects representing a cross-section of drivers took part in the study, thirty at the Turner-Fairbanks Highway Research Center in McLean, Virginia and thirty at the University of Missouri--Rolla in Rolla, Missouri.

Two of the seven signs were word messages and five were symbolic signs. The results …

Structural Design Of Coal-Fueled Power Plant Ductwork, Stanley Pearce Rader

Doctoral Dissertations

"An absence of a comprehensive procedure for design of coal-fueled power plant ductwork currently exists in the publicly available literature. This dissertation presents such a procedure.

An overview of the ductwork design environment, including major components of the air and flue gas flow paths, design loads and temperatures, corrosion considerations, and physical configurations, is given. Design criteria for materials, corrosion inhibition, minimum plate thicknesses, temperature effects, allowable stresses and deflections, and vibrations are proposed. A detailed design procedure based on the allowable stress design philosophy is presented, and computer programs implementing the design procedure are provided. An alternate design procedure …

Oxidation Kinetics Of Polycrystalline Srtio₃ And Lacro₃, Chi-Kung Jerry Yu

Doctoral Dissertations

"The oxidation kinetics of polycrystalline SrTiO₃ and LaCrO₃ were determined by measuring the time and temperature dependence of the weight and conductivity change of reduced samples. A region of fast diffusion followed by a reduced diffusion tail was observed in the TGA measurements. This observation can be interpreted as the initial diffusion along the boundaries and then spreading out into the lattice. The absence of the tail in the conductivity measurements is due to the high electron and hole mobility at the boundaries. The electrical conductivity and TGA results on Nb-doped LaCrO₃ show that at low oxygen …

Amphiphilic Association Structures And Some Aspects Of Foam Stability, Jia-Hwa Fang

Doctoral Dissertations

"This investigation was performed in order to study two interesting and important problems in foams.

Foam separation was studied in the model system of water - sodium octylsulfonate - decanol. The efficiency of foam separation as a function of surfactant concentration and decanol content were measured. The results were related to the association structures of amphiphiles in aqueous systems.

Foam polymerization was conducted in the amphiphilic system containing water, polymerizable surfactant and oleyl alcohol. Liquid foams were produced in one three - phase region. The location and optical pattern of liquid crystals on the foam surface were observed by photomicroscope …

The Modeling And Analysis Of Multi-Component, Multivalent Biospecific Adsorption, Bo Henrik Arve

Doctoral Dissertations

"A general model is presented and used to predict the dynamic behavior of the adsorption, wash, and elution stages of biospecific adsorption (affinity chromatography) in finite bath and column operations. The model accounts for film and pore diffusional mass transfer resistances and the rates of interaction between adsorbates and ligands. For column operations the effect of axial dispersion in the flowing fluid stream is included. The model is applicable to single and multi-component biospecific as well as non-specific adsorption, and the adsorbates may be monovalent or multivalent. In the elution stage both non-selective and selective elution of monovalent adsorbates is …

Hydrodynamic Characteristics And Coal Combustion Modeling Of A High Velocity Fluidized Bed (Solids Friction Factor, Two Phase Flow, Pressure Profile, Fast), Ronald Wayne Breault

Doctoral Dissertations

A Loop Fluidized Bed (LFB) based on the fast fluidization concept is a novel method for effective solid-gas contact and can play an important role in coal combustion. It can be operated under pressure making it eminently suited for the production of high temperature gas from coal for operating gas turbines for power generation. The LFB can operate over a wide range of gas flow rates and coal can be introduced at various points without excessive pressure drops. Further, it is possible to capture higher amounts of sulfur dioxide due to the use of fine dolomite or limestone particles. This …

Risk And Uncertainty (Utility, Decision), Paul Snow

Doctoral Dissertations

The conventional theory of decision making under risk relies on axioms that reflect assumptions about people's subjective attitudes towards wealth. The assumptions are unverifiable, and the axioms are too restrictive. They forbid some decision rules that a plausibly rational decision maker ("DM") could find useful.

A new method, at once less restrictive and less dependent upon subjective assumptions, motivates expected utility techniques by assuming that a DM wishes to place an upper limit on the probability of ruin. All bounded-above, increasing functions defined over a suitable domain can serve as utility functions.

Now, DM can evaluate lotteries according to their …

The Occurrence And Control Of Aluminum In Drinking Waters (New Hampshire), Shahin Rezania

Doctoral Dissertations

Because of the ever increasing concern over the health effects associated with aluminum, this study was designed to determine the behavior of aluminum in a water treatment facility using alum in the coagulation process. The plant chosen was the Arthur Rollins Water Treatment Facility located in Durham, New Hampshire. Laboratory jar tests, as well as actual monitoring, were conducted. The important parameters examined included pH, temperature and fluoride. Also, a comparison between natural river water and a colored model water was performed in the laboratory.

Aluminum was determined using both the Atomic Absorption Spectrophotometry (AAS) method and the Eriochrome Cyanine …