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Molecular Analyses Of Motility And Chemotaxis Genes And Their Organization In Borrelia Burgdorferi., Yigong Ge Jan 1996

Molecular Analyses Of Motility And Chemotaxis Genes And Their Organization In Borrelia Burgdorferi., Yigong Ge

Graduate Theses, Dissertations, and Problem Reports (ETD)

Motility and chemotaxis have been considered as important candidates for the study of virulence in many pathogenic spirochetes, including B. burgdorferi. Little is known about the underlying mechanisms of motility and chemotaxis. In this study, we have carried out an extensive search for the motility and chemotaxis genes in B. burgdorferi. The unique technique of "semi-random PCR chromosome walking" was developed and used to clone several large motility and chemotaxis gene clusters. Together with the previously reported flaB and flgE genes, 38 motility and chemotaxis related genes (more than 36 kb) were identified. These genes demonstrated extensive homology with their …

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Acoustic Emission Monitoring Of Concrete Structures Using Waveguides., Yidong Eddie He Jan 1996

Acoustic Emission Monitoring Of Concrete Structures Using Waveguides., Yidong Eddie He

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study is to develop acoustic waveguides for Acoustic Emission (A.E.) monitoring of concrete structures, in order to overcome the difficulty of high acoustic attenuation in concrete. Solid embedded waveguides, liquid-filled embedded waveguides and solid surface waveguides have been developed in this study. An analytical model of a waveguide with infinitely thick cladding was used to study the wave propagation in an embedded solid waveguide. The analysis revealed the guideline to construct an ideal embedded waveguide with efficient acoustic transmission, that is the existence of a real wavenumber. An embedded waveguide fulfilling the above criterion has not been constructed physically …

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Development And Improvement Of Numerical Models For Roof Supports In Underground Coal Mines., Song Guo Jan 1996

Development And Improvement Of Numerical Models For Roof Supports In Underground Coal Mines., Song Guo

Graduate Theses, Dissertations, and Problem Reports (ETD)

Roof bolting has been one of the age-old, yet important issues in the coal mining industry. Although roof bolts have been widely used in underground coal mines with a great success in recent decades, the real mechanism by which they reinforce the mine roof is still relatively unknown. As a consequence, almost all the roof bolts used are mis-matched under the specific conditions of geology, mining, etc., which inevitably either causes a safety problem such as roof fall if they are under-designed in terms of bolting parameters such as type, tension, bolt length and bolting patterns, or induces unnecessary cost …

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Trade And Development: Special Application To Malaysia, 1960-1990., Thamir M. Salih Jan 1996

Trade And Development: Special Application To Malaysia, 1960-1990., Thamir M. Salih

Graduate Theses, Dissertations, and Problem Reports (ETD)

Malaysia is a developing country located in South East Asia. Malaysia has a rich natural-resource base and is a trade-oriented society. Between 1960 and 1990, Malaysia's GDP increased more than seven fold and per capita income also increased considerably. The relative importance of sectoral shares of output and employment shifted from the primary (agricultural) sector towards the secondary and tertiary sectors. The objective of this study is to investigate the factors that have contributed to the rapid development of the Malaysian economy and, thus, determine how the Malaysian economy has been transformed from a low level equilibrium to a high …

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Modeling And Application Of Thin-Walled Composite Beams In Bending And Torsion., Hani A. Salim Jan 1996

Modeling And Application Of Thin-Walled Composite Beams In Bending And Torsion., Hani A. Salim

Graduate Theses, Dissertations, and Problem Reports (ETD)

Due to their favorable properties, pultruded fiber reinforced plastic (FRP) composite beams and columns are increasingly finding their way into infrastructure applications. In order for the structural applications of FRP members to be successful, engineering design analysis procedures are needed to accurately model such advanced materials and systems. Nonclassical effects such as shear lag, shear deformations, warping, torsion, and elastic couplings need to be included in the modeling of FRP composite structural members. In this research, we address the analytical/experimental modeling of thin-walled open and closed composite sections in bending and torsion. Micro/macro-mechanics models are investigated to allow the modeling …

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Evaluation Of Mineral Project Using Simulation And Expert System: "A Case For A Gold Mine Evaluation"., Saied Sarkarat Jan 1996

Evaluation Of Mineral Project Using Simulation And Expert System: "A Case For A Gold Mine Evaluation"., Saied Sarkarat

Graduate Theses, Dissertations, and Problem Reports (ETD)

Discounted cash flow analysis (DCF) is the most common evaluation method used to evaluate capital investment. However, this method is static in nature and does not recognize the existence of managerial flexibility. An evaluation method that recognizes managerial flexibility is desired and may be obtained by the development of an investment and operational simulation coupled with an expert system. An investment simulation was developed using a gold mine as an example with stochastic output price and a combination of conventional cash flow analysis and an expert system. Actual gold prices from 1973 to 1984 were used as the historical data …

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Development Of Cost-Based Multi-Defect-Type Control Chart Using Fuzzy Set Theory., Mustafa Saadeddin Shraim Jan 1996

Development Of Cost-Based Multi-Defect-Type Control Chart Using Fuzzy Set Theory., Mustafa Saadeddin Shraim

Graduate Theses, Dissertations, and Problem Reports (ETD)

Traditional attribute control charts for nonconformities or defects, such as c or u charts, assume that all defect types are binary in nature. However, some defect types have varying degree of seriousness within them. As a result, the plotted value on the control chart may not capture the true quality status of the product in question. Moreover, in many situations, large products may have multiple types of defects. These defects may be different from one another in terms of their severity. The classification process in attribute inspection tasks for the traditional control charts does not consider the variability within some …

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Expressive Endeavors Utilizing Advanced And Emerging Technical Means., Paul Louis Siciliano Jan 1996

Expressive Endeavors Utilizing Advanced And Emerging Technical Means., Paul Louis Siciliano

Graduate Theses, Dissertations, and Problem Reports (ETD)

Throughout most of known human existence the processes, materials and tools of production were available to individuals involved in both utilitarian and expressive work. Since the Renaissance, however, the exponential growth and sophistication of technology has made it impossible for the majority of artists to gain access to many potential tools for expression. Despite the complexity of myriad technical means, some individuals have been successful in utilizing advanced technologies for expressive purposes. The purpose of this study was to examine the methods these individuals employed to access and apply sophisticated technologies for expressive production. A qualitative research methodology consisting of …

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Process Modeling And Analysis For Pulsed Gas Metal Arc Welding Of An Aluminum Automotive Spaceframe., Sankaran Subramaniam Jan 1996

Process Modeling And Analysis For Pulsed Gas Metal Arc Welding Of An Aluminum Automotive Spaceframe., Sankaran Subramaniam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Procedure development for welding of thin section (1-4mm) aluminum, using Pulsed Gas Metal Arc Welding (PGMAW) requires considerable understanding of the process physics. Selection of ideal pulse parameters for different joint designs is a non-trivial task. Several aspects of the process were studied, in order to have a better fundamental understanding of the process. Welding was conducted using 1.2 mm diameter 4047 aluminum electrode and argon shielding gas. An extensive collection of high speed pictures were taken over a wide range of pulse parameters using a laser shadowgraph setup to study the metal transfer behavior. Current, voltage and arc light …

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Study Of Jointless Bridge Behavior And Development Of Design Procedures., Hemanth Kumar Thippeswamy Jan 1996

Study Of Jointless Bridge Behavior And Development Of Design Procedures., Hemanth Kumar Thippeswamy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Jointless bridge literature is reviewed and the analytical information on jointless bridge behavior is synthesized in this research. The behavior of jointless bridges is found to depend on superstructure to substructure stiffness ratio, including span length and abutment heights, load types and their combinations, time dependent creep and shrinkage effects, hinge locations, foundation types, soil properties, boundary conditions, approach slab type, approach slab length, and approach slab connection details. The analytical data are generated by conducting a parametric study of hypothetical and real bridges. The data are synthesized to develop a better understanding of jointless bridge behavior. In order to …

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Study Of The Effect Of Pulsating Combustion On The Calcination Reaction., Robert Edwin James Jan 1996

Study Of The Effect Of Pulsating Combustion On The Calcination Reaction., Robert Edwin James

Graduate Theses, Dissertations, and Problem Reports (ETD)

Limestone calcination is an important process for the power generation industry. Calcination is the precursor to the sulfation process which is used for flue gas cleanup. This research studies the effects of a pulse combustion exhaust stream on the calcination of limestone. Results are presented for different types of limestone, injected at different exhaust stream conditions and locations in the exhaust stream. Certain conditions show promising results in the form of larger calcination percentages and larger surface areas. Results of pulsating cases were compared to results found using a steady combustor. A computer code modeling the pulse combustor was used …

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The Use Of Fracture Mechanics To Predict The Stress Distribution In Coal Mine Pillars., James Michael Kramer Jan 1996

The Use Of Fracture Mechanics To Predict The Stress Distribution In Coal Mine Pillars., James Michael Kramer

Graduate Theses, Dissertations, and Problem Reports (ETD)

Because coal resources are dwindling, it is necessary to mine seams that are more difficult to support structurally. The mining industry needs a mine layout that is safe, but designed to be competitive in the world market. Presented in this dissertation is a technique that predicts the stress distribution in coal mine pillars. This approach uses an analytic equation to predict stress and yield characteristics; so, in some respects, it is as accurate as numerical modeling. It uses fracture mechanics to model many structures including longwall gob, yield pillars, cribs, posts, longwall chocks and hydrostatic loads. It models the yield …

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Pictorial Graphic Organizers, Navigation, And Hypermedia: Converging Constructivist And Cognitive Theories., Cheryl Ann Krawchuk Jan 1996

Pictorial Graphic Organizers, Navigation, And Hypermedia: Converging Constructivist And Cognitive Theories., Cheryl Ann Krawchuk

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study examined differences in cognitive structure, content knowledge, navigational difficulties, and personal interviews between organizer and non-organizer students in a hypermedia environment. This information was used to ascertain the feasibility of using the pictorial graphic organizer as a tool to help alleviate navigational difficulties in a learner-controlled hypermedia environment without imposing structure on the student. Sixty-nine students from an undergraduate course completed a computer questionnaire as well as a pre content knowledge test and a Pathfinder network. They were then exposed to a hypermedia program with the organizer group using a program that contained a pictorial graphic organizer and …

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Nucleation And Growth Studies Relevant To Diamond Thin Film Synthesis., John Michael Lannon Jan 1996

Nucleation And Growth Studies Relevant To Diamond Thin Film Synthesis., John Michael Lannon

Graduate Theses, Dissertations, and Problem Reports (ETD)

Studies of diamond nucleation and growth were conducted with molecular and ionic gas species in an ultra-high vacuum system. Thermal interactions of C{dollar}\\rm\\sb2H\\sb4{dollar} on Si(100) 2 x 1 surfaces held at 1000 K produced carbon films comprised of SiC, sp{dollar}\\sp2{dollar}-C, and sp{dollar}\\sp3{dollar}-C, as determined using Auger electron spectroscopy. The presence of elemental Si on the surface throughout the growth process indicated that a surfactant mediated growth process, with Si as the surfactant, was responsible for both SiC and sp{dollar}\\sp3{dollar}-C growth. The presence of sp{dollar}\\sp2{dollar}-C in the films was most likely due to interfacial strain effects. Medium energy (500 eV) methyl …

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Clinical Assessment And Random Error Reduction Related To The Acoustic Reflection Technique., Jerry Keith Legg Jan 1996

Clinical Assessment And Random Error Reduction Related To The Acoustic Reflection Technique., Jerry Keith Legg

Graduate Theses, Dissertations, and Problem Reports (ETD)

Published research has shown that a simple SCUBA-type mouthpiece may effectively be used in conjunction with an acoustic impedance tube to perform an acoustic reflection test which is thought to well characterize cross-sectional area changes in the larger airways of human subjects. The test, however, has only been performed on the researchers themselves. To test the applicability of the technique in the clinical setting, acoustic testing was conducted on a population of known asthmatic subjects and age-matched controls. It is shown that the SCUBA-type mouthpiece is not appropriate for general population testing. An enhanced mouthpiece is required which both prevents …

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The Impact Of Activity-Based Costing On Project Bidding., John Edward Mansuy Jan 1996

The Impact Of Activity-Based Costing On Project Bidding., John Edward Mansuy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Applying activity-based costing to project bidding will assist companies make better bid selections, use overtime or subcontracting more effectively, and minimize under/over allocation of overhead costs. Two models, the Overhead Allocation Model and the Bidding Strategies Model, were constructed to explore the implications of activity-based costing on bidding strategies. The Overhead Allocation Model simulates the two step overhead allocation method of activity-based costing. The model, based on user input, assigns cost accounts to overhead cost pools, allocates cost pools to activities using resource cost drivers, calculates a unit cost for each activity cost driver and allocates activities to projects using …

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Nucleation And Growth Of Gan On Sapphire By Mbe, Steven Buczkowski Jan 1996

Nucleation And Growth Of Gan On Sapphire By Mbe, Steven Buczkowski

Graduate Theses, Dissertations, and Problem Reports (ETD)

GaN was grown by molecular beam epitaxy in an effort to determine nucleation and growth conditions which lead to high quality, single-crystal films. Atomic force microscopy (AFM) was used to show that growth under Ga-rich conditions promotes the nucleation of films with large nucleation domains leading to a lower density of intrinsic defects related to domain boundaries. These conditions are also shown to promote a 2-D growth mode resulting in films with a high degree of nucleation domain coalescence and surface roughnesses below 2 nm. Addition of atomic hydrogen, using a thermally-cracked source, is shown to increase the growth rate …

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A Historical Study Of Educational Reform Policy In Morocco., Abdellah Benahnia Jan 1996

A Historical Study Of Educational Reform Policy In Morocco., Abdellah Benahnia

Graduate Theses, Dissertations, and Problem Reports (ETD)

Though information about literacy development in Morocco can be often found in professional publications, little has been done in regard to the impact of the socio-cultural, economic, and political variables on the development of educational policy in that country. This study has historically examined the educational reform policy in the independent Kingdom of Morocco in order to see how the above variables have affected the implementation of most major policies that had taken place. It also examined the role of the indigenous Islamic traditional type of education; the role of Salafiyya movement in creating a unique type of nationalism; and …

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The Dynamic Ssi Of A Shallow Buried Plate Under Impact Loading., Shen-En Chen Jan 1996

The Dynamic Ssi Of A Shallow Buried Plate Under Impact Loading., Shen-En Chen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Soil is a particulate material, which provides a unique behavior when interacting with its adjacent structure. The dynamic soil-structure interaction (SSI) phenomenon involving in a shallow-buried flexible plate under impact loading is studied. The objective of this study is to understand this interaction process, which has caused load-relieves on the buried plate. The investigation includes an experimental reproduction of the phenomenon and numerical simulation. Plexiglass plates were used as a buried flexible roof structure, and low-velocity impact loadings were generated into the soil. Measurements of the interaction loads between the sand and the plate, and the accelerations of the buried …

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An Analysis Of Decision Styles As A Predictor Variable For Levels Of Creativity And/Or Orientations Toward Risk-Taking Of Knowledge Workers., Beth Ann Hill Jan 1996

An Analysis Of Decision Styles As A Predictor Variable For Levels Of Creativity And/Or Orientations Toward Risk-Taking Of Knowledge Workers., Beth Ann Hill

Graduate Theses, Dissertations, and Problem Reports (ETD)

The problem of this study was to determine if decision styles of knowledge workers could predict a level of creativity and/or an orientation toward risk of knowledge workers. A biographical survey and two self-scoring instruments were administered to each subject. The first instrument, Decision Style Inventory (DSI) by Alan Rowe and Richard Mason classified the subjects according to four basic decision styles: directive, analytical, conceptual and behavioral. The second instrument, The Creatrix Inventory (C&RT) by Richard Byrd measured the subject's level of creativity and orientation toward risk. There were two primary hypothesis: Hypothesis One examined the statistical strength of the …

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An Experimental Study Of Fluidically Oscillated Natural Gas Flames: Flow Fields And Emissions., Marshalla Michelle Wright Jan 1996

An Experimental Study Of Fluidically Oscillated Natural Gas Flames: Flow Fields And Emissions., Marshalla Michelle Wright

Graduate Theses, Dissertations, and Problem Reports (ETD)

The intent of this project was to investigate the flow field and emissions of laterally and radially oscillating natural gas flames produced by slot and axisymmetric fluidic nozzles used as burners. The behavior of flames produced by three nozzles was studied. A parametric study was conducted while visualizing and quantifying the flame flow field and measuring emissions produced by the flame. Nozzle configurations included two different-sized axisymmetric nozzles and one slot nozzle. Flame oscillation frequency varied from zero to 35 Hz; equivalence ratios ranged from 0.6 to 1.4. A focusing Schlieren system was designed, constructed, and used to visualize the …

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Soil-Structure-Fluid Interaction By Hybrid Fem-Bem., Chaojin Xu Jan 1996

Soil-Structure-Fluid Interaction By Hybrid Fem-Bem., Chaojin Xu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Soil-structure-fluid systems like U-lock, pipelines, and storage tanks are widely used in engineering practice. Relatively very few works can be found in the literature for the analysis of a soil-structure-fluid system subjected to externally applied loads or seismic excitations. The main purpose of this study is to develop a numerical method for the analysis of a soil-structure-fluid system. In the formulation of the presented numerical method, the flexibility of the thin plate structure is treated with a finite element formulation, while the difficulty in modeling the infinite extent of the soil is overcome by a boundary element formulation. The contained …

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The Hydraulics Revolution: Science And Technical Design Of Urban Water Supply In The Enlightenment., Edward Howard Winant Jan 1996

The Hydraulics Revolution: Science And Technical Design Of Urban Water Supply In The Enlightenment., Edward Howard Winant

Graduate Theses, Dissertations, and Problem Reports (ETD)

In the later half of the eighteenth century, French engineer-scientists revolutionized hydraulics. Funded by Royal research programs, these experimenters formulated predictive equations for flow velocities and quantities. Their results were published throughout Europe and America, causing a distinct change in the practice of designing aqueducts. Case studies of aquaeducts for Edinburgh in 1721 and New York City in 1838 detail the changes in the practice of hydraulic design. A comparison of these two examples illustrates the practical effects of the new hydraulic formulas. These are presented in chronological order, along with the details of the French research programs which so …

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Three-Staged Turbocharger Modeling With Passive Control System., Prabhakar K. Metlapalli Jan 1996

Three-Staged Turbocharger Modeling With Passive Control System., Prabhakar K. Metlapalli

Graduate Theses, Dissertations, and Problem Reports (ETD)

High altitude operation of internal combustion engines requires multiple stages of turbo-compression to maintain sea level density at the engine intake to maintain rated power. Aurora Flight Sciences Corporation has selected a set of automotive turbo-compressor components for the Rotax engine chosen for high altitude performance of the Theseus aircraft. Prior to construction and testing, Aurora predicted the system performance by power and RPM matching, using factory component performance data in the form of a spreadsheet. They concluded that their system could be controlled by a single wastegate control over the entire design altitude range of the Theseus aircraft. The …

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Automated Lumber Processing System (Alps): Computerized Hardwood Lumber Gradings And Industrial Processing., John Edward Moody Jan 1996

Automated Lumber Processing System (Alps): Computerized Hardwood Lumber Gradings And Industrial Processing., John Edward Moody

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Automated Lumber Processing System (ALPS) is a lumber processing system developed over the last 27 years in an attempt to provide rough lumber mills with an alternative to traditional, low yield, labor intensive techniques. As lumber prices continue to climb (from {dollar}196.00 per thousand board feet in 1955 to well over \\{dollar}1000.00 in 1996), improving the yield from lumber while minimizing cost has become crucial for manufacturers who wish to remain in business. ALPS addresses these problems as a complete package from the initial grading to the final processing of the lumber into cuttings used by the manufacturer in …

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Cad For Roll Forming Process., Sankar Rao Nallapati Jan 1996

Cad For Roll Forming Process., Sankar Rao Nallapati

Graduate Theses, Dissertations, and Problem Reports (ETD)

Roll forming is a high production process for forming sheet metal into desired uniform cross-sectional shapes by feeding the metal through successive sets of rotating tools known as form tools. Several parameters, both quantitative and qualitative, ought to be considered while designing roll forming tools, such as section geometry, material properties of the product, number of forming stages, operation sequence, mill parameters and roll profiles. The conventional design methods, however, do not account properly for the interactions between important mechanical and geometrical properties and consequently they may lead to improper flower pattern sequence and roll profiles for the form tools. …

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Mitigation Of Blast Effects With Geogrid-Reinforced Soil Backfills., Alan Paul Ohrt Jan 1996

Mitigation Of Blast Effects With Geogrid-Reinforced Soil Backfills., Alan Paul Ohrt

Graduate Theses, Dissertations, and Problem Reports (ETD)

Several military attack scenarios involve the detonation of explosive in the soil backfill surrounding a target structure. In this study, experiments and numerical simulations were performed to determine if the enhanced mechanical properties of geogrid-reinforced soil backfills could mitigate blast effects from buried explosions. The dynamic response of an explosively-loaded, geogrid-reinforced sand was successfully characterized, identifying and quantifying certain blast mitigating effects. Six high explosive experiments were conducted, each involving a 0.91 kg nitromethane explosive charge placed at 76.2 cm depth within a test pit of compacted fill. Two experiments were unreinforced, serving as control tests. Three experiments were conducted …

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Assessing The Impact Of The West Virginia K-12 Ruralnet Project On Teachers' Views., Thomas P. Ditty Jan 1996

Assessing The Impact Of The West Virginia K-12 Ruralnet Project On Teachers' Views., Thomas P. Ditty

Graduate Theses, Dissertations, and Problem Reports (ETD)

Teachers play a key role in implementing curriculum changes in the science classroom. The evaluation of teachers' views regarding the relationships that exist between science, technology, and society can strengthen the link between curricular reforms and the content that students' acquire in their learning experiences and contribute to the improvement of preservice and inservice teacher education programs. The purpose of this investigation was to determine if participation in the West Virginia K-12 RuralNet Project has impacted teachers' views about science, technology, and society interactions. This investigation employed a matched-group quasi-experimental research design which involved 58 West Virginia (K-12) teachers. The …

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The Toroidal Helical Antenna Analysis And Performance Evaluation., Wael Shaker Ellithy Jan 1996

The Toroidal Helical Antenna Analysis And Performance Evaluation., Wael Shaker Ellithy

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Toroidal Helical Antenna (THA) is a newly patented antenna design, that has a small physical profile. The THA is a wire antenna which consists of one or more conductor helices wrapped about a toroidal core, usually with different pitch senses. The conductor helices are generally fed from one or more ports. An important class of THA is the Contrawound Toroidal Helical Antenna (CTHA) which has two helices with uniform pitches, opposite senses, and one feeding port. This dissertation presents the development and the implementation of a computer model for investigating the THA in order to optimize its performance by …

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Visual And Iconographic Design Principles: Implications For Computer-Assisted Instruction., Lindia Lee Gordon Jan 1996

Visual And Iconographic Design Principles: Implications For Computer-Assisted Instruction., Lindia Lee Gordon

Graduate Theses, Dissertations, and Problem Reports (ETD)

The purpose of this study was to provide educators and developers of computer-assisted instruction with a validated, concise list of visual and iconographic design principles that should be considered when designing graphical icons to stimulate learning as a part of the user interface of their courseware packages in order to create more effective learning. A panel of 12 experts in a modified Delphi study identified and validated visual and iconographic design principles necessary in the development of icons for CAI. As a result of this study, 37 visual and iconographic design principles were identified and validated. The final conclusions of …

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