Digital Commons Network^™

Secondary Dust Generation In Rotary Coal Cutting., Danqing Xu

Graduate Theses, Dissertations, and Problem Reports (ETD)

In a rotary coal cutting system, the mined coal has to be transported through the cutting path. This transportation of mined coal through the cutting zone of a rotary cutting head is comparable to a rotary grinder. In the "grinder", the mined coal particles are subjected to secondary comminution, known as regrinding. A significant amount of coal dust could be generated during regrinding. This study was undertaken to investigate the mechanisms of regrinding and dust generation, to quantify the amount of dust generated during regrinding and evaluate the effects of influencing parameters on dust generation. Three comminution mechanisms of particles …

Prediction And Amelioration Of Acid Mine Drainage., Walter Mark Hart

Graduate Theses, Dissertations, and Problem Reports (ETD)

Two aspects of acid mine drainage (AMD) production were studied on a laboratory scale: the role of leaching, and the effectiveness of phosphate amelioration. The leaching study was based on an assumption of an earlier oxidation/leaching field model: that oxidation is independent of leaching. A SAS program was written which can simultaneously fit all three parameters of this field model. The model was generalized to include the effect of initial sulfate sulfur. A deterministic oxidation/leaching model was developed and applied to two continuous, unsaturated flow trickle bed reactors. First-order leaching rate constants were calculated to be 0.0888 days{dollar}\\sp{lcub}-1{rcub}{dollar} for refuse …

Bending And Bond Behavior And Design Of Concrete Beams Reinforced With Fiber-Reinforced Plastic Rebars, Salem Samir Faza

Graduate Theses, Dissertations, and Problem Reports (ETD)

The use of non-corrosive fiber reinforced plastic (FRP) rebars in lieu of mild steel rods is investigated. The present work covers experimental testing of twenty-seven concrete beams reinforced with FRP rebars subjected to bending, twenty-four cantilever specimens subjected to bond forces, and twelve straight pull-out specimens. The following response of concrete beams reinforced with FRP rebars were investigated: pre- and post-cracking behavior, load-deflection and stress variations, elastic and ultimate load carrying capacities, crack widths and patterns, bond stress and embedment length, and modes of failure. In order to take advantage of the high tensile strength of FRP rebars (80 to …

Prediction Of Wear In A Fluidized Bed., William Allen Rogers

Graduate Theses, Dissertations, and Problem Reports (ETD)

A procedure to model the wear of surfaces exposed to a fluidized bed is formulated. A stochastic methodology adapting the kinetic theory of gases to granular flows is used to develop an impact wear model. This uses a single-particle wear model to account for impact wear from all possible particle collisions. An adaptation of a single-particle abrasion model to describe the effects of many abrading particles is used to account for abrasive wear. Parameters describing granular flow within the fluidized bed, necessary for evaluation of the wear expressions, are determined by numerical solution of the fluidized bed hydrodynamic equations. Additional …

Manufacturing Data Representation Using An Object-Oriented Data Model., Ping Ji

Graduate Theses, Dissertations, and Problem Reports (ETD)

An integrated database plays a key role in the development of a Computer Integrated Manufacturing System (CIMS) and a Manufacturing Data Base (MDB) is one of the necessary components of the integrated data base. The MDB needs to have information on part geometry features, operation processes, operating parameters, machine tools, cutting tools, jigs and fixtures. The MDB should also provide capabilities to model, store and manipulate manufacturing data in a manner suitable to the users. The commercial Data Base Management Systems (DBMS) are not widely used in manufacturing application primarily because the conceptual and internal modeling tools that they provide …

Promotion Practices In Accredited Engineering Technology Programs., Martha Kelsey Shouldis

Graduate Theses, Dissertations, and Problem Reports (ETD)

A survey of administrators of accredited engineering technology programs was completed in the spring of 1990 for the purpose of identifying, analyzing, and describing the basic credentials and key concepts related to promotion in academic rank of engineering technology faculty. The survey was limited to programs located in four-year public and private colleges, technical institutes, and community colleges. The results of the survey revealed differences in the relative importance of the criteria utilized in evaluating faculty for promotion within and between the four broad categories of Teaching, Institutional Service, Research and Publication, and Public Service. Administrators responding to this survey …

An Artificial Associative Neural Net For Underground Mine Landmark Recognition., Peijian Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

A new bi-directional associative memory (BAM), a type of artificial neural net, is proposed, defined, demonstrated and tested as the core classifier in a landmark recognition system for underground mine navigation. The simulation of this new BAM shows improved ability in recognizing images of objects as compared with the BAM proposed by Kosko. This dissertation documents: (1) A new bi-directional associative memory model which shows an obvious improvement over the Kosko BAM in applications of pattern recognition; (2) A new distinctive system structure using the proposed BAMs for multiple feature space pattern recognition applications; (3) The analysis of simulation results …

Computable General Equilibrium Models For United States Nonfuel Minerals Policy., Shih-Mo Lin

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over the past fifteen years, the U.S. mineral industry has undergone profound structural change--a change which is a combination of both supply- and demand-side effects. On the supply side, the once advantageous and profitable position held by the U.S. mineral industry has been gradually replaced by its competitors worldwide, resulting in its loss of competitiveness in not only domestic but also international markets. On the demand side, the growth rate of both intensity of use for conventional metals and GNP, the two widely used measures explaining the demand for metals, has been slowing down for most of the past twenty …

Thermomechanical Properties Of Fiber-Reinforced Plastic (Frp) Bars., Wei-Pin Wu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fiber reinforced plastic (FRP) bars have been recognized as a possible substitution for steel rods because of their noncorrosive properties. However, there is a need to establish sufficient data bank and to develop reliable analytical tools for the analysis of such FRP bars before they could confidently be used and their performance could be predicted and assured in advance. This research is concern with such an effort towards experimental as well theoretical characterization of fiber reinforced plastic (FRP) bars under static loads. An integrated micro-macro three-dimensional finite element (EHSM) model and generalized plain-strain elasticity solution (ES) are employed to perform …

A Method For Predicting Rock Fragmentation And Blast Casting., Shih Wen Wang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fragmentation and burden velocity are the major concerns of any blasting operation. A good estimation of fragment size distribution before blasting is very useful and helpful for selecting the proper equipment for loading, hauling, and crushing rocks. The burden velocity can be used to predict the center of mass movement. There are three basic variables that determine the blasting effects. They are rock properties, explosive properties, and drilling patterns. These together include more than twenty factors that can affect the blasting results. The development of a blasting model which considers most of these factors is the main task of this …

Behavior Of Bolt And Adhesive Connections In Glass Fiber Reinforced Plastic Members, James R. Doyle

Graduate Theses, Dissertations, and Problem Reports (ETD)

Structural fasteners must be engineered to resist a large variety of loading conditions. Isotropic materials with high shear strength can be designed to withstand multidirectional loading. However, since fiber reinforced plastic materials are direction dependent, a more in-depth understanding of the effects of loading direction and fiber orientation is needed. To achieve a better understanding of load transfer and failure mechanisms in FRP fasteners, an experimental program has been devised which includes static testing by varying overlap areas and connector strengths. From the results of these tests, more accurate joint designs should be possible.

Connectors such as arc welding and …

Development Of A Measure Of Therapist Trustworthiness, Gregory M. Alberts

Graduate Theses, Dissertations, and Problem Reports (ETD)

Graduate and professional therapist training programs emphasize the acquisition of technical skills (Stevenson & Norcross, 1987) and deemphasize the promotion of interpersonal and relationship competencies (Lambert, 1989; Schiffman, 1987 ) . The content of such training programs and the procedures by which the competencies of prospective mental health practitioners are developed and evaluated have been critic ized because neither are based on an adequate fund of clinically relevant empirical knowledge (Ford, 1979; Garfield, 1977; Matarazzo, 1978; Ponterotto & Furlong, 1985; Scofield & Yoxtheimer, 1983).

Quality Economics In Total Quality Control., Fu Qiang Yang

Graduate Theses, Dissertations, and Problem Reports (ETD)

The purpose of this research is to develop a general approach to quality economics in Total Quality Control. Based on microeconomics theory and the development of prevailing quality control approaches, the research develops a set of economic quality concepts which provide a solid theoretical base for economic design and evaluation in quality control. A number of quality economics modeling procedures are established in the phases of both the consumer's and the producer's decision makings on product quality as well as their interactions. In the context of a total quality control approach, the research first analyzes consumer behavior under quality discrimination …

Rapid Pyrolysis Of Eastern And Western Oil Shales In An Entrained Reactor., Guo-Qing Zhang

Graduate Theses, Dissertations, and Problem Reports (ETD)

An entrained reactor system (LFER) has been used to study the rapid pyrolysis kinetics for both eastern (New Albany) and western (Colorado) oil shales. Under the condition of high heating rate, a fundamental understanding of the processes influencing oil production and product quality/composition was obtained. Flow visualization and temperature characterization in the LFER were conducted to provide a critical laminar flow and isothermal reaction zone. Calibration curves depicting the flow regimes confirmed that the existing inlet and reactor design can be operated without particle dispersion caused by turbulence. A thermocouple tree was successfully utilized to identify the conditions necessary to …

Development Of A Mechanistic Model For Prediction Of Subsidence Over Longwall Mines., Richard Douglas Begley

Graduate Theses, Dissertations, and Problem Reports (ETD)

Several different longwall subsidence prediction techniques were analyzed in this study in order to select the most appropriate method for modification and expansion to various field conditions and general applications. These techniques include those developed by the United States Bureau of Mines(USBM) and the National Coal Board(NCB), in addition to the following influence functions: (1) Bals, (2) Knothe's, and (3) zone area. The method that was selected as most appropriate for modification was initially developed from a recent field study conducted in Northern West Virginia over a three year period at 3 different mine sites. The model was refined and …

An Examination Of The Relationship Of Violations Of Students' Expectancies Of Teachers' Nonverbal Immediacy And Perceived Teachers' Nonverbal Immediacy Behaviors On Learning., Mark Alan Seiffert

Graduate Theses, Dissertations, and Problem Reports (ETD)

This investigation examined a model of Burgoon's Violation of Expectancy theory (Burgoon, 1978; Burgoon & Hale, 1987) as applied to the instructional context. Students' perceptions of teacher nonverbal immediacy were used in conjunction with the Expectancy Violation Model to predict amount of student learning. At the beginning of a term, students were asked to complete questionnaires assessing the expected level of nonverbal immediacy for one of their instructors. One week later, and at midterm, students were asked to complete questionnaires assessing the level of nonverbal immediacy evidenced by their instructors and the students' perceptions of the amount of learning that …

An Exploratory Study Of Moral Judgment Of Higher Education Administrators., Betsy Barger Cook

Graduate Theses, Dissertations, and Problem Reports (ETD)

The relationships between the moral judgment score as measured by Rest's Defining Issues Test and certain demographic variables of higher education administrators were investigated. In addition, five personal interviews with higher education administrators were conducted to obtain personal anecdotes on decision making in ethical dilemmas. The population for the quantitative portion was a sample of all presidents, vice presidents for academics or provosts and academic deans at all four-year public higher education institutions in the United States. The research method used the DIT, an objective psychological test of moral judgment, and a demographic questionnaire developed by the researcher. To determine …

Methane Recovery And Suppression In Simulated Sanitary Landfills., Bassem Ibrahim Haddad

Graduate Theses, Dissertations, and Problem Reports (ETD)

Methane gas production in MSW landfills and its migration are well documented in the literature. Maximizing methane yield per unit refuse mass and minimizing its migration are beneficial for energy recovery purposes. This research project was based on suppressing methane generation in landfills, and its production in a controlled external reactor. Three different systems of simulated sanitary landfills were constructed at West Virginia University. System 1 simulated a conventional sanitary landfill. In System 2, leachate was recycled, and its pH was controlled by adding caustic. In System 3, anaerobic digestion supernatant was added to MSW to provide nutrients and bacterial …

Development Of A Resistivity Method To Detect Underground Mined Openings., Fazlollah Ziaie

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this study, a new resistivity method has been developed and tested in three phases; simulated model, similitude model, and field survey. This new resistivity method is a combination of the Bristow arrangement and line electrode method. Three line electrodes are chosen so that the sinkhole electrode is emplaced at far distance from the other two electrodes. Any of the two electrodes and the sinkhole electrode is activated and several resistivity profiles perpendicular to the line electrode are prepared for different electrodes activation. Subsurface cavities cause resistivity anomaly. These anomalies are interpreted and are used to estimate the depths and …

Relationships Between Supervisory Safety Contributions And Productivity Accomplishment Among Limestone Quarries., J Owen Weber

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study determined the relationship between how employees perceived their supervisors relative to their safety contributions and productivity as measured in limestone tons per man hour. This study was undertaken for the purposes of providing to enterprise safety function manager's research based data which would be useful in ascertaining the safety contributions of their front line supervisors as well as discovering those items beneficial to focused supervisory training. The investigator constructed a survey instrument consisting of a Likert scale evaluation of fifty-seven supervisory safety duties and responsibilities. These statements were the result of a jury of experts revalidation of the …

Modeling The Supply Response Of Energy Resources: The Case Of Non-Associated Natural Gas In West Virginia., Omowunmi Odemyi Iledare

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this study, we have attempted to conduct an economic and policy analysis of the West Virginia natural gas producing industry. The research concentrated on industry activities, objectives and outcomes in the post-NGPA era. The primary goal was to determine the role of economic and market conditions on natural gas supply. First, the structure, conduct and performance of the West Virginia gas producing industry were examined with respect to key features of market structure--concentration, vertical and horizontal integration and barriers to entry. Second, a West Virginia gas supply (WVGAS) model based on the assumption of a price-taker industry was constructed. …

Improved Energy Recovery From Municipal Solid Wastes In Sanitary Landfills By Two-Phase Digestion Of Biomass., Chukwu Onu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Gas recovery from sanitary landfills is increasingly being viewed as a valuable resource for its potential as a source of fuel gas. The operation and performance of a two-phase laboratory-scale anaerobic digestion system for improved gas production was studied for a period of two years. The system consisted of a simulated landfill loaded with representative municipal solid waste (MSW) and a separate upflow anaerobic methane reactor. The concept under investigation was the separation of the acidogenic and the methanogenic phases of anaerobic fermentation, converting the sanitary landfill into an acid reactor and using a separate upflow fixed-film anaerobic reactor for …

The Evolution Of American Interests In British East Africa And The Western Indian Ocean Region To 1929., Aman Walid Kabourou

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation investigates a little known aspect of American diplomacy--America's interest in East Africa and the Western Indian Ocean during the colonial period. The study explores the historical link between the United States and Eastern Africa from the 1820s until 1929. Many scholars, aware of America's increased commercial and military involvement with East Africa and the Western Indian Ocean since the end of World War II, have attributed the American presence there to the Cold War struggles between the Soviet Union and the United States. This dissertation rests on the contention that the period between 1900 and 1929 influenced significantly …

An Adult Education Program Planning Model For The National Universities Of Egypt., Waguida A. El Bakary

Graduate Theses, Dissertations, and Problem Reports (ETD)

In view of the success of American program planning models and their potential contribution to adult education centers at the national universities of Egypt, the researcher wanted to investigate the usefulness of such models to the Egyptian national universities. Six U.S. program planning models by Boyle (1981), Houle (1972), Knowles (1970), Knox and Associates (1980), Sork and Buskey (1986), and Tyler (1949) were selected and synthesized. The researcher developed a model, based on 15 steps and 73 key tasks. She introduced it for testing to determine its usefulness for the national universities of Egypt. Testing was done through the use …

The Applicability Of Limit Equilibrium Methods Of Analysis To Different Types Of Slope Stability Problems., Sun Chai Lee

Graduate Theses, Dissertations, and Problem Reports (ETD)

This investigation was conducted to determine the applicability of the limit equilibrium methods of slope stability analysis. Six of the most widely used methods of slope stability analysis were selected from methods which satisfied different equilibrium conditions. An examination of the differences among these methods was undertaken. Through investigation of the mechanics involved in the analysis. Parametric studies were also conducted to establish quantitative trends in the resulting factors of safety. Results of the investigation indicate that: (1) The most significant factor in the stability analysis of slopes is the shear strength parameters of soil, i.e., cohesion and angle of …

An Integrated Computer Model For Predicting Surface Subsidence Due To Underground Coal Mining: "Cispm"., Yi Luo

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation is a part of the results of a research effort. The objective of the research was to develop a reliable, comprehensive and easy-to-use computer model for predicting surface movement and deformation induced by underground coal mining. The subsidence prediction model developed is capable of (1) predicting the final subsidence on a flat or moderate surface; (2) predicting the dynamic subsidence on a flat or moderate surface for an operating longwall panel; (3) recommending subsidence parameters based on the geological and panel layout information for those new coal mines; (4) deducing the subsidence parameters from the subsidence data collected …

Taking A Stand: A Naturalistic Study Of Stance Negotiation In Student Teaching., Jody Messinger Wolfe

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research was an exploratory investigation of stance in teacher learning. The concept of stance is suggested by the work of Bruner and Schon and is rooted in a constructivist perspective on knowledge. When applied to teaching, stance can be defined as a teacher's position toward the world of teaching, discernible in the verbal and behavioral language of practice. A teacher's stance is negotiated through experiencing various elements of teaching, constructing cognitive representations of these experiences, and taking a stand toward them. The researcher employed a naturalistic design to study stance in the context of one secondary Social Studies student …

Citation Analysis And Emerging Technologies: Foundational Technical Developments In Optical Disk Technology., Thomas Tunnell Wrenn

Graduate Theses, Dissertations, and Problem Reports (ETD)

One reason a given technology emerges is that the technical means of the technology are improved--made more efficient, faster, more reliable. This causes changes in the "socio-technical interface" between the technical means and the organization in which it is applied, and it becomes practical to use the improved technical means in new applications and additional organizations. Technical developments that decisively affect the technical workability and the economic usefulness of a product or process, which permit rapid changes in a technology and its rate of emergence, are termed foundational technical developments (FTDs). We often want to be able to identify which …

Simulation Of Boundary Coal Thickness Sensors., Michael Gordon Nelson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Underground coal mining practice often requires that some coal be lift in place at the seam boundaries after mining, for purposes of ground control, quality control, machine guidance, of good operating practice. Many methods for measuring the thickness of boundary coal have been developed, but only the natural gamma method has been used in routine operations. Use of this method is constrained by the level and consistency of the natural gamma background in the bordering strata, the accuracy of the gamma detection instrument, and the elevation profile of the seam boundary being detected. Computer simulations for three commercially available gamma …

A Study Of Human Performance In The Event Of An Unexpected Robot Motion., Yves Beauchamp

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study evaluates factors that could affect human performance in the event of an unexpected robot motion. The study evaluated the following factors associated with a robot work station: illumination level, noise level, the luminance contrast between the robot and its background, the amount of attention required by a task being performed while monitoring the movement of the robot, the motion speed of the robot, and finally the field where unexpected motions were initiated. The dependent variable measured was the distance the robot moved before the subject detected and responded to the unexpected motion. In a main experiment, nine subjects …