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Conservation And Ecology Of Fringing Salt Marshes Along The Southern Maine/New Hampshire Coast, Pamela Ann Morgan

Doctoral Dissertations

The small, fringing salt marshes that line the edges of estuaries in southern Maine and New Hampshire were the focus of this research. Although larger meadow marshes in New England have been studied extensively, little is known about the ecology of fringing marshes. Not only are fringing marshes much more numerous than meadow marshes in northern New England, they are often restored or created as mitigation for marsh impacts. Five ecological functions (primary production, soil organic matter accumulation, sediment trapping and binding, wave dampening and maintenance of plant diversity) were compared in meadow marsh and fringing marsh sites, and sometimes …

Number, Please: New Hampshire Telephone Operators In The Predial Era, 1877--1973, Judith N. Moyer

Doctoral Dissertations

The predial telephone era in New Hampshire stretched from about 1877 to 1973. This dissertation examines predial telephone operating in the state as a category of women's work. While growing out of and responding to technical invention and development, telephone operating had deep roots in women's social roles; gender defined occupational options, the work environment, the rules of employment, wages, and expectations. As the telephone system developed, differences between telephone operating in large and small exchanges developed; the urban operator eventually worked under conditions of traffic volume, supervision, and control that the rural operator often did not. To uncover the …

Mathematics And Socio -Cultural Behavior: A Case Study Of The Enculturation Of A New Mathematician, Timothy Byron Gutmann

Doctoral Dissertations

Research has shown that mathematics as we know it is a product of the socio-cultural climate in which it was developed. This research attempts to address the related question of how being involved in mathematics influences the socio-cultural lives of mathematicians. A new Ph.D. mathematician hired in his first faculty position was observed for a period of 13 weeks, most during his first semester. Analysis of this long-term, in depth case study followed ethnographic methods and drew on theories of rites of passage, organizational socialization, self-identity, and evolution. The role of mathematics in the departmental culture and in the newcomer's …

Disturbance Indicators For Time Series Reconstruction And Marine Ecosystem Health Impact Assessment, Benjamin Harrison Sherman

Doctoral Dissertations

A systematic reconstruction of Multiple Marine Ecological Disturbances (MMEDs) involving disease occurrence, morbidity and mortality events has been undertaken so that a taxonomy of globally distributed marine disturbance types can be better quantified and common forcing factors identified. Combined disturbance data include indices of morbidity, mortality and disease events affecting humans, marine invertebrates, flora and wildlife populations. In the search for the best disturbance indicators of ecosystem change, the unifying solution for joining data from disparate fields is to organize data into space/time/topic hierarchies that permit convergence of data due to shared and appropriate scaling. The scale of the data …

Integration Of Battery Energy Storage With Flexible Ac Transmission System Devices, Zhiping Yang

Doctoral Dissertations

"This dissertation, consisting of five papers, presents the results of research on the incorporation of battery energy storage into a Static Synchronous Compensator (StatCom). The main contribution of this body of work is the establishment of the modeling and control of the StatCom/BESS in power system dynamic applications. The first paper is focused on the steady state characteristics of the StatCom and StatCom/BESS. The characteristic curves of output voltage and output power were proposed and used in comparing the functionality of the StatCom and StatCom/BESS. In the second paper, a StatCom model was proposed and used in power flow analysis. …

A Thin-Film Micromanufactured Oxygen Microelectrode, James Clay Mcguyer Jr.

Doctoral Dissertations

The methods for production of recessed oxygen microelectrodes developed by Whalen, et al. (1967) and improved upon by Linsenmeier, et al. (1987) are dated production methods by the standards of sensor production of the current time. The production process for this type of polarographic oxygen sensing electrode has remained unchanged for over 10 years, and is a time consuming, extremely low-yield process. The goal of this project has been to use the techniques of micromanufacturing available at the Institute for Micromanufacturing at Louisiana Tech University to construct a recessed oxygen microelectrode with a batch process that has higher yield than …

The Microchannel Flow Of A Micropolar Fluid, Guohua Liu

Doctoral Dissertations

Micro-channel flows have been computed to investigate the influence of Navier-Stokes formulation for the slip-flow boundary condition, and a micro-polar fluid model, respectively.

The results of the slip boundary condition show that the current methodology is valid for slip-flow regime (i.e., for values of Knudsen number less than approximately 0.1). Drag reduction phenomena apparent in some micro-channels can be explained by slip-flow theory. These results are in agreement with some computations and experiments.

An ad hoc micro-polar fluid model is developed to investigate the influence of micro effects, such as micro-gyration, in micro-scale flows. The foundation of the ad hoc …

Observable Outcomes And Performance Effects Of The Application Of Theory Of Constraints To Organizational Management, Martha Lair Sale

Doctoral Dissertations

The objectives of the study were to empirically examine the relationships among the three elements of the Theory of Constraints (TOC), a number of observable outcomes expected to be associated with application of TOC, and business unit performance. Measures were developed for each of the elements of TOC and a number of observable outcomes (OUTCOMES) expected to be associated with practice of TOC. TOC is defined as consisting of scheduling logistics (LOGISTICS), the Thinking Process (THINKING), and non-traditional performance measures (MEASURES). A previously developed and widely used measure of business unit performance (PERFORMANCE) was employed.

The sampling frame for this …

Environmental Behavior Of Hafnium: The Impact On The Disposition Of Weapons-Grade Plutonium, Gary S. Cerefice '89

Doctoral Dissertations

Experimental and analytical studies were performed to examine the environmental behavior of hafnium and its utility as a neutron poison for the disposition of weapons-grade plutonium in Yucca Mountain. The hydrolysis of hafnium was investigated by potentiometric titration in solutions of varying ionic strength to determine the stability constants for the first four monomeric hydrolysis products. The specific ion interaction theory is used to extrapolate these results to infinite dilution. The solubility of hafnium hydroxide and a meta-stable hafnium carbonate solid phase are studied via solubility experiments using ICP-AES. An upper bound for the stability constant of the first carbonate …

Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao

Doctoral Dissertations

The problem of long-term structural behavior of CIPP liners under external hydrostatic pressure has been characterized as a structural instability problem which is induced by time-dependent material deformation or creep. It is also a contact problem since the liner deflection is externally constrained by the host pipe. The intrinsically nonlinear problem is investigated by means of finite element simulation, with emphases on (a) the essential structural behaviors and mechanisms of buckling, and (b) the influences of inelastic material properties (i.e. yield strengths and creep rates) and geometrical parameters on liner's buckling resistance.

A liner first deforms as a free pipe …

An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo

Doctoral Dissertations

This study presents information upon which the state of Louisiana can base its ozone State Implementation Plans (SIPs) designed to achieve planned emissions reduction that are required by the Clean Air Act (CAAA) of 1990. The research investigation included an assessment survey on a number of Transportation Control Measures (TCMs) and their degree of acceptability by the residents of Lake Charles area of Louisiana, the research target area. The TCMS were first ranked on the basis of people's perception of each TCM and four TCMs were later analyzed for cost-effectiveness using computer mathematical models. The Traffic Flow Improvements TCM was …

Cracking In Cycloaliphatic Epoxy/Aluminum Composite Electrical Bushings, Keith Alan Parker

Doctoral Dissertations

The problem of cracking in electrical apparatus bushings as a result of thermal stresses was investigated. The bushings were composed of cycloaliphatic epoxy insulators with embedded aluminum conductors. The problem is due to the difference in coefficients of thermal expansion of the two materials. A solution to the problem had been to coat the conductors before they were formed together with the epoxy insulators. The coating was assumed to prevent cracking by allowing movement between the two materials as their dimensions changed during thermal expansion and contraction. The contribution of the coating was to be established.

The hypothesis was that …

Multifield Spectral Analysis Of Human Respiratory Sounds, John William Ray Jr.

Doctoral Dissertations

Computer analysis of human respiratory sounds (phonopneumography) has been attempted since the 1960s with poor results. Steady research efforts by numerous researchers have failed to yield a practical diagnostic tool to replace the physician and the stethoscope. This has been the result of the high degree of variability in proposed analysis parameters from subject to subject.

The purpose of this research is to examine a new approach to phonopneumography by comparing multiple lung fields of the same subject for the same breath in order to develop the diagnostic parameters. This approach has the advantage of allowing the subject to provide …

A Systematic Integration Of Register Allocation And Instruction Scheduling, Yukong Zhang

Doctoral Dissertations

In order to achieve high performance, processor architecture has become more and more complicated. As a result, compiler-time optimizations have become more and more important for the effective use of a complex processor. One of the promising compiler-time optimizations is the integration of register allocation and instruction scheduling based on register-reuse chains. In the previous approach, however, the generation of register-reuse chains was not completely systematic and consequently created many unnecessary dependencies that restrict instruction scheduling.

This research proposes a new register allocation technique based on a systematic generation of register-reuse chains. The first phase of the proposed technique is …

Graphical Display And Data Structure For Virtual Prototyping, David William Manry

Doctoral Dissertations

One of the goals of engineering firms is to bring better products to market faster. Although concurrent engineering can aid in this endeavor, it requires that all areas of an organization work simultaneously. Thus, current product data must be accessible to everyone.

Virtual prototyping allows this simultaneous exchange of information. Virtual prototyping not only replaces the physical model in product development with a virtual model, but also it goes further by allowing data associated with each part of the model to be accessed. This data is not limited to just geometric properties but could contain other quantifiable properties, such as …

Sonar Three-Dimensional Image Formation For Underwater Vehicular Collision Avoidance, Gary Robert Boucher

Doctoral Dissertations

The last ten years have shown a marked increase in research into Autonomous Underwater Vehicles. A key component of this research is the ability to “look” ahead of the vehicle's projected path and translate active sonar returns into three-dimensional (3-D) computer data structures used to navigate and avoid obstacles. This need to avoid obstacles is also common to other underwater vehicles including submersibles.

Of special interest to this research is the “Occupancy Grid Framework.” This technique divides the forward looking sonar field into cells. These cells can be maintained either in spherical or cartesian coordinate systems.

This research demonstrates a …

Three-Dimensional Imaging Of Turbulent Flows: Optical Tomography With Proper Orthogonal Decomposition, Barbara Jeanne Pelliccia

Doctoral Dissertations

Fluid flows with turbulent characteristics are evident in many important engineering and scientific applications. For years researchers have investigated fluid flow turbulence but have not attained a complete physical understanding and quantitative description of the turbulent fluid motion. One approach has been to identify and classify the organized, or coherent, structures imbedded in the turbulence. Research in this area has been restricted by the lack of complete three-dimensional descriptions of the flow. In many studies, the velocity field is measured in either one or two dimensions using mechanical probes which can disrupt the downstream evolution of the flow and offer …

Unbound Pavement Base Courses: Parallel Study Of Stiffness And Drainage Characteristics, Moussa Issa

Doctoral Dissertations

The purpose of this project was to study the effects of fines (minus #4 sieve) on permeability and stiffness characteristics of unbound base materials and to propose an optimumgradation that will satisfy these two parameters. One type of highway base material--crushed limestone--was used in the study. A total of 75 laboratory tests were conducted and distributed--25 respectively on permeability, resilient modulus and unconfined compression. The permeability test data were collected using a low-head permeameter. The resilient modulus and unconfined compression test data were collected by the mean of the MTS (Machine Testing System) with a load cell capacity of 22-kips. …

Controls On Spatial And Temporal Variability In Nitrous Oxide Fluxes Across A Tropical Rainforest Ecosystem In The Luquillo Experimental Forest, Puerto Rico, Claire Patricia Mcswiney

Doctoral Dissertations

Nitrous oxide (N2O) is a trace gas that contributes to the greenhouse effect and participates in the reactions that destroy stratospheric ozone. Soil microbial processes are significant producers of this trace gas, particularly in tropical areas, which are considered major sources in the global N2O budget. Nitrous oxide fluxes to the atmosphere are variable in space and time. In this study, spatial and temporal variability in surface N2O fluxes were assessed as well as the major environmental controls on N2O production for a tropical rainforest watershed in northeastern Puerto Rico. A static chamber technique was used to assess surface fluxes …

Behavioral And Physiological Responses Of The Lobster, Homarus Americanus, To Temperature: A New Synthesis, Steven Harold Jury

Doctoral Dissertations

Temperature has a pervasive influence on lobster behavior, physiology and ecology and affects their subsequent distribution in thermally variable habitats such as estuaries and coastal areas. A multidisciplinary approach, including field and laboratory studies, was used to show: (1) that lobsters sense temperature with warm and cool thresholds as small as 0.1--0.2°C; (2) the relationship between temperature and activity is not linear, but instead switches between a high activity level in warmer months (10--20°C) and a lower level in colder months (<10°C) with transition periods in the spring and fall; (3) Parallel studies in the lab and field show that daily levels of activity are not greatly influenced by small temperature variations (i.e. tidally induced changes of 14°C), but activity levels are significantly higher in the field (249 +/- 55.1 m/d) than in the laboratory (88 +/- 12.0 m/d); (4) lobsters prefer a narrow range of temperatures over others available in a thermal gradient and avoid temperatures >23.5 +/- 0.4°C, suggesting that they behaviorally thermoregulate. While this preferred temperature shifts seasonally, the final preferred temperature …

Preparation And Characterization Of Derivatized Microparticles Immobilized In Hydrogel Membranes For Optical Chemical Sensing Based On Polymer Swelling, Eric William Miele

Doctoral Dissertations

Hydrogel membranes containing aminated microparticles have been investigated for reflectance based optical sensing. The membranes were evaluated by UV/Vis spectrophotometry, for potential use in a remote distributive fiber optic chemical sensor. This work describes efforts for improving the signal and decreasing the overall response time of the membranes. The microparticles were prepared by dispersion and seeded emulsion polymerization techniques. The microparticles were derivatized to introduce pH sensitivity. The hydrogel membranes containing swellable microparticles are turbid. Scattering occurs at the microparticle-hydrogel interface and is based on refractive index changes accompanying polymer swelling. The particles swell in response to hydrogen ion concentration, …

Topics In Chaotic Secure Communication, Andrew Thomas Parker

Doctoral Dissertations

Results in nonlinear dynamics and chaos during this decade have been applied to problems in secure communications with limited success. Most of these applications have been based on the chaotic synchronization property discovered by Pecora and Carroll in 1989 [37]. Short [44, 45, 48] demonstrated the effectiveness of nonlinear dynamic (NLD) forecasting methods in breaking this class of communication schemes. In response, investigators have proposed enhancements to the basic synchronization technique in an attempt to improve the security properties. In this work two of these newer communication systems will be analyzed using NLD forecasting and other techniques to determine the …

New Methods For Modeling Accelerated Life Test Data, Michelle Hopkins Capozzoli

Doctoral Dissertations

An accelerated life test (ALT) is often used to obtain timely information for highly reliable items. The increased use of ALTs has resulted in nontraditional reliability data which can not be analyzed with standard statistical methodologies. I propose new methods for analyzing ALT data for studies with (1) two independent populations, (2) paired samples and (3) limited failure populations (LFP). Here, the Weibull distribution, which can accommodate a variety of failure rates, is assumed for the models I develop. For case (1), a parametric hypothesis test, a Bayesian analysis and a test using partial likelihood are proposed and discussed. For …

Hardware-Software Codesign In A High-Level Synthesis Environment, Tamas L. Visegrady

Doctoral Dissertations

Interfacing hardware-oriented high-level synthesis to software development is a computationally hard problem for which no general solution exists. Under special conditions, the hardware-software codesign (system-level synthesis) problem may be analyzed with traditional tools and efficient heuristics. This dissertation introduces a new alternative to the currently used heuristic methods. The new approach combines the results of top-down hardware development with existing basic hardware units (bottom-up libraries) and compiler generation tools. The optimization goal is to maximize operating frequency or minimize cost with reasonable tradeoffs in other properties.

The dissertation research provides a unified approach to hardware-software codesign. The improvements over previously …

A Constraint-Based Framework For Configuration, Daniel Sabin

Doctoral Dissertations

The research presented here aims at providing a comprehensive framework for solving configuration problems, based on the Constraint Satisfaction paradigm. This thesis is addressing the two main issues raised by a configuration task: modeling the problem and solving it efficiently. Our approach subsumes previous approaches, incorporating both Simplification and further extension, offering increased representational power and efficiency.

Modeling. We advance the idea of local, context independent models for the types of objects in the application domain, and show how the model of an artifact can be built as a composition of local models of the constituent parts. Our modeling technique …

The Mut-2 Mutator Of Caenorhabditis Elegans, Kathrine Queta Flint Boese

Doctoral Dissertations

The mut-2 mutator plays multiple regulatory roles in the germ line of C. elegans. In addition to regulating germ line transposition of at least four distinct transposon families (Tc1, Tc3, Tc4 and Tc5) mut-2 is implicated in chromosome segregation. Animals that harbor the mut-2 mutator produce broods with a higher incidence of males phenotype (Him) as a result of an increase in X chromosome non-disjunction during meiosis.

Using the Him phenotype conferred by mut-2(r459), I mapped the gene to the dpy-14 sem-4 interval on LGI. However, efforts to identify a molecular clone of the gene were hampered because the available …

The Development Of Rna Probe And Rt-Pcr Assays For The Detection Of Enteroviruses In Sludge, Amy Elisabeth Moore

Doctoral Dissertations

Many wastewater treatment plants generate more sludge than can be disposed of by conventional means. The United States Environmental Protection Agency (USEPA) has encouraged communities to dispose of sludge by land application. Sludge may contain enteric viruses that are known to survive for long periods of time in sludge-amended soil and can travel great distances, potentially contaminating surface and ground water.

Standard cell culture methods for the detection of enteric viruses are costly and results are not obtained for 30 or more days. The development of methods that provide results more quickly and with lower cost are needed.

A 32P …

Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu

Doctoral Dissertations

"This research focused on the analysis and design of rigid retaining walls subjected to earthquakes and considered nonlinear foundation soil properties. The simultaneous sliding and rocking movements of retaining walls were considered. Seven field conditions, including moist, submerged, perched and saturated backfill with a sloping drain, were specified by design codes. A computer program capable of computing displacement using real time history records or equivalent sinusoidal motions was developed. Finally, a dynamic design procedure was proposed for practicing engineers.

The study revealed that maximum shear modulus in foundation soil, maximum ground acceleration, and soil nonlinearity had significant effect on the …

Machine Tool Accuracy Characterization, Error Modeling And Compensation Using Telescopic Ballbar And Laser Interferometer, Yalcin M. Ertekin

Doctoral Dissertations

"This dissertation presents the results of the research investigation on the machine tool accuracy characterization, error modeling and error compensation using telescopic ballbar and laser interferometer. Increasing demand for both higher machine tool accuracy and machining tolerances has resulted in a great need to measure and characterize the accuracy of NC machine tools and minimize machine tool induced errors on machined components before manufacturing parts, instead of inferring it from parts already machined. Using a telescopic magnetic ballbar, the results of the accuracy assessment of an old Bridgeport Series I CNC 2 1/2 axes vertical machining center are presented in …

Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon

Doctoral Dissertations

"The Southern Fire Clay District of Missouri was intensely mined during the late-1800’s to mid-1900’s for its valuable resource of high refractory clays deposited within Pennsylvanian sinkholes “paleosinks”. Mining operations have produced modifications in the Ozark aquifer, which in effect has possibly increased the instability of this paleokarst terrain and the potential of further environmental impacts to the land. Evidence supporting this hypothesis are: (1) A southerly shift in the regional groundwater divide relative to the topographic divide. This possibly is caused by the distribution of leaking clay pits, which suggests that the bedrock permeability or hydraulic conductivity has been …