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Articles 170131 - 170160 of 198087

Full-Text Articles in Engineering

Development And Application Of Adaptive Dynamic Grids For Wake Vortex/Ground Interaction, Ilker Emin Türkgeldi Jul 1999

Development And Application Of Adaptive Dynamic Grids For Wake Vortex/Ground Interaction, Ilker Emin Türkgeldi

Mechanical & Aerospace Engineering Theses & Dissertations

An adaptive and dynamic grid approach is developed for the numerical computations of wake vortex flow problems with ground interaction. The unnecessary grid points at the far field of the original, large, single zone grid are removed for computational efficiency. Next, the grid is modified into an adaptive one, where the fine core region keeps track of the vortices and can be split into two regions when the vortex separation distance exceeds a specified limit length. In the final step a multi zonal feature is added to this grid by means of two embedded grids placed at the vortex centers …


Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates Jul 1999

Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates

Electrical & Computer Engineering Theses & Dissertations

This paper shows that the combination of a second-order neural network parameter update algorithm and internal network feedback can be effectively used for adaptive, nonlinear, dynamical system identification and control. Adaptive neural identification and control algorithms are typically utilized for real-time applications where the rate of adaptation is often critical. A fast, adaptive network parameter update algorithm is presented.

Simulation results show that this algorithm is capable of quickly identifying and adapting to changes in system parameters, making it feasible to use for real-time control and fault accommodation applications.


Field Enhancement In Silicon Nanotip Field Emitter Arrays, Ajith Varghese Jul 1999

Field Enhancement In Silicon Nanotip Field Emitter Arrays, Ajith Varghese

Electrical & Computer Engineering Theses & Dissertations

No abstract.


Dynamic And Interactive 3d Simulation Over The World Wide Web, Rajesh Vennam Jul 1999

Dynamic And Interactive 3d Simulation Over The World Wide Web, Rajesh Vennam

Electrical & Computer Engineering Theses & Dissertations

The thesis presents the development of a new and novel three-dimensional simulation tool over the WWW using Virtual Reality Modeling Language (VRML). VRML is a 3D analog to HTML and serves as a simple, multiplatform language for publishing 3D Web pages. In general, most people use VRML for developing three-dimensional models or worlds that provide little or no interaction for the users. This tool combines interaction and dynamic object creation. A thorough study of VRML is done to explore the features of VRML that could be combined to develop methodologies for creation of dynamic and interactive 3D objects over the …


An Analytical Approximation For The Excess Noise Factor Of Avalanche Photodiodes With Dead Space, Majeed M. Hayat, Zikuan Chen, Mohammad Rezaul Karim Jul 1999

An Analytical Approximation For The Excess Noise Factor Of Avalanche Photodiodes With Dead Space, Majeed M. Hayat, Zikuan Chen, Mohammad Rezaul Karim

Electrical and Computer Engineering Faculty Research and Publications

Approximate analytical expressions are derived for the mean gain and the excess noise factor of avalanche photodiodes including the effect of dead space. The analysis is based on undertaking a characteristic-equation approach to obtain an approximate analytical solution to the existing system of recurrence equations which characterize the statistics of the random multiplication gain. The analytical expressions for the excess noise factor and the mean gain are shown to be in good agreement with the exact results obtained from numerical solutions of the recurrence equations for values of the dead space reaching up to 20% of the width of the …


Exploring Participation Processes For Technology Development: Case Studies Of Biotechnology Research And Development Projects In Thailand, Omjai Yuktavetya Jul 1999

Exploring Participation Processes For Technology Development: Case Studies Of Biotechnology Research And Development Projects In Thailand, Omjai Yuktavetya

Engineering Management & Systems Engineering Theses & Dissertations

There is increased awareness in the organizational and management literature that participation can make contributions in technology development. One of the problems in developing biotechnology in Thailand is that only a small portion of publicly funded research and development projects directly result in commercial success. Among the reasons cited (TDRI 1992a) is a lack of collaboration between various stakeholders; therefore, an effective technology policy to support their participation is needed. This research explores current participation processes in biotechnology research and development projects in Thailand in which there were different perspectives among various stakeholders. The quantitative and qualitative methodologies developed here …


Large Amplitude Pitching Of Supermaneuver Delta Wings Including Flow Control, Yahia A. Abdelhamid Jul 1999

Large Amplitude Pitching Of Supermaneuver Delta Wings Including Flow Control, Yahia A. Abdelhamid

Mechanical & Aerospace Engineering Theses & Dissertations

The unsteady, three-dimensional Navier-Stokes equations are solved to simulate and study the aerodynamic response of a delta wing undergoing large amplitude pitching motion up to 90° angle of attack. The primary model under consideration consists of a 76° swept, sharp-edged delta wing of zero thickness, initially at zero angle of attack. The freestream Mach number and Reynolds number are 0.3 and 0.45 × 106, respectively. The governing equations are solved time-accurately using the implicit, upwind, Roe flux-difference splitting, finite-volume scheme. Both laminar and turbulent flow solutions are investigated. In the laminar flow solutions, validation of the computational results is carried …


The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba2cu3o7-X, William C. Hicks, Fatih Dogan, M. Strasik, A. C. Day, Kevin E. Mccrary Jun 1999

The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba2cu3o7-X, William C. Hicks, Fatih Dogan, M. Strasik, A. C. Day, Kevin E. Mccrary

Materials Science and Engineering Faculty Research & Creative Works

Platinum is an important additive in YBa2Cu3O7-x [123] powders for melt processing and growth of large, oriented crystals, but its role in liquid loss during the growth cycle is poorly understood. A series of experiments were conducted to determine how platinum effects liquid loss, and to study the solubility limit of platinum in 123. Both atomically mixed and solid state platinum sources were compared. Crystals were grown on a nonreactive setter so that liquid loss could be clearly distinguished by weight from reaction products with the setter. Based on weight loss studies there was little …


The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba₂Cu₃O₇₋ₓ, William C. Hicks, Fatih Dogan, Michael Strasik, Arthur C. Day, Kevin E. Mccrary Jun 1999

The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba₂Cu₃O₇₋ₓ, William C. Hicks, Fatih Dogan, Michael Strasik, Arthur C. Day, Kevin E. Mccrary

Materials Science and Engineering Faculty Research & Creative Works

Platinum is an important additive in YBa2Cu3O7-x [123] powders for melt processing and growth of large, oriented crystals, but its role in liquid loss during the growth cycle is poorly understood. A series of experiments were conducted to determine how platinum effects liquid loss, and to study the solubility limit of platinum in 123. Both atomically mixed and solid state platinum sources were compared. Crystals were grown on a nonreactive setter so that liquid loss could be clearly distinguished by weight from reaction products with the setter. Based on weight loss studies there was little …


Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf Jun 1999

Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Funded Proposals

Electrostatic discharge protection and electromagnetic interference shielding is provided by applying to a dielectric substrate a composition comprising a polymeric matrix and a conductive filler component. The conductive filler component comprises electrically conductive metal particles and at least one electrically conducting polymer.


Electroluminescent Illumination System, Dirk J. Broer, David Braun, Antonius H.J. Venhuizen, Christianne R.M. De Witz Jun 1999

Electroluminescent Illumination System, Dirk J. Broer, David Braun, Antonius H.J. Venhuizen, Christianne R.M. De Witz

Electrical Engineering

An illumination system has an active layer which includes an electroluminescent material, the active layer being located between an optically transparent electrode layer and a reflective electrode layer. A reflective polarizer is present at a side of the transparent electrode layer facing away from the active layer. A sub-beam incident on the polarizer and having an unwanted polarization is reflected back to the active layer, where it is again partially depolarized to recover a component having the desired state of polarization. The invention also relates to a flat-panel picture display device which includes such an illumination system.


The Effectiveness Of An On-Line Graduate Engineering Management Course, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray Jun 1999

The Effectiveness Of An On-Line Graduate Engineering Management Course, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray

Engineering Management and Systems Engineering Faculty Research & Creative Works

In the summer of 1997, the Engineering Management Department of the University of Missouri-Rolla's (UMR) began offering its first Internet-based graduate level course. This course, Advanced Production Management, was designed to utilize a combination of Internet-based tools, such as EMail and Chat rooms to create a alternative means for the delivery of course material. This paper will draw these following conclusions from more than a year of research, which included over 100 students in six different course offerings. First, the Internet-based students performed equally as well as the control group students. Second, students tend to have exaggerated time requirement expectations …


Triangulation Rangefinder And Sight Positioning System, Jeffrey Hargrove, William G. Wickham, John E. Briggs Jun 1999

Triangulation Rangefinder And Sight Positioning System, Jeffrey Hargrove, William G. Wickham, John E. Briggs

Mechanical Engineering Patents

A rangefinder includes an angle sensitive transducer and a programmed data processor to calculate the distance to a target. In one embodiment, the rangefinder also includes a point-to-point measuring device. Another embodiment provides a linear actuator to selectively move a sight indicator vertically. A yet additional embodiment includes a liquid crystal display which displays information to the user.


Environmental Applications Of Gps, Samuel A. Vigil, Dora Zueck Jun 1999

Environmental Applications Of Gps, Samuel A. Vigil, Dora Zueck

Civil and Environmental Engineering

The use of the Global Positioning System (GPS) has revolutionized air travel, ocean navigation, land navigation, and the collection of environmental data. Although a basic civilian GPS receiver can be purchased for as little as $100, the receiver is only the tip of a 12 billion dollar iceberg! This paper will discuss the history and basic operation of the Global Positioning System, a satellite-based precision positioning and timing service developed and operated by the Department of Defense. It will also describe the accuracy limitations of the civil GPS service and how accuracy can be enhanced by the use of differential …


Application Of Noise Control In Environmental Engineering Education, Harold M. Cota, Kristy Grace Jun 1999

Application Of Noise Control In Environmental Engineering Education, Harold M. Cota, Kristy Grace

Civil and Environmental Engineering

Noise control is both a factor in the health and safety of those in the workplace and in the annoyance and interference of the quality of life at home. This falls squarely in the realm of the Environmental Engineering Profession. Noise, its effects and control, is an important element of a few Graduate Environmental Engineering Programs, but it does not have a role in most undergraduate programs. One objective of this paper is to demonstrate that noise is an issue needing to be addressed in Environmental Engineering Programs and to suggest that making it a requirement at the undergraduate level …


Early Experimentation With Civil Engineering Materials, James L. Hanson Jun 1999

Early Experimentation With Civil Engineering Materials, James L. Hanson

Civil and Environmental Engineering

A new project-based teaching method emphasizing laboratory experimentation is being used at Lawrence Technological University. It has excited and energized the students about civil engineering applications. Engineering concepts are introduced early in the students’ academic careers using civil engineering materials. Laboratory activities related to a Civil Engineering Materials course are being used for outreach, recruitment, and an intensive laboratory experience. A departmental effort has included supporting an outreach program and expanding a freshman CE Materials course. This new teaching method has affected and complemented university recruitment and retention efforts. The course introduces incoming students to engineering analysis and the basic …


Training Graduate Student Instructors Effectively: The University Of Michigan Model, Trevor S. Harding Jun 1999

Training Graduate Student Instructors Effectively: The University Of Michigan Model, Trevor S. Harding

Materials Engineering

No abstract provided.


Industrial Engineering Made Simple, Deena Daggett, Sema E. Alptekin Jun 1999

Industrial Engineering Made Simple, Deena Daggett, Sema E. Alptekin

Industrial and Manufacturing Engineering

Many high school students these days do not quickly recognize or identify Industrial Engineering (IE) procedures, practices, and products. Recruitment of qualified students into IE programs requires continuous planning, publicizing, and networking. Traditional recruitment efforts have included high school visits, brochures & flyers, and university-sponsored workshops. However, these techniques have only achieved mediocre success. Currently, a need exists for new promotional materials that utilize visual tools and provide a “hands-on” approach. We have developed several exercises that successfully introduce IE. Two such exercises are explained in this paper. The first exercise demonstrates the differences between Assembly line and Cellular Manufacturing …


Jun 1999, Tractor Museum Jun 1999

Jun 1999, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Foundation Account Friends of NE State Museum Newsletter


The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer Jun 1999

The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer

U.S. Mine Ventilation Symposium

This is the description of ventilation planning conducted by the author in 1952 as his thesis for the German degree of Dipl.-Ing. Since the problems have not changed, most of the work done is not much different from what one would do today. Even the tools have remained the same, except for the computers, which were not around yet. To compensate for this, certain planning techniques were developed which are now in danger of being forgotten.


Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh Jun 1999

Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh

U.S. Mine Ventilation Symposium

Longitudinal ventilation systems in transit and rail tunnels are typically analyzed by one dimensional ventilation network simulation models, such as the Subway Environment Simulation (SES) program. However, in recent years computational fluid dynamics (CFD) modeling has been utilized in conjunction with one-dimensional ventilation network programs to study ventilation systems for large volume spaces such as transit stations and rail overbuilds, as well as for vehicular tunnels. CFD uses numerical methods to simulate complex fluid flow phenomena in three dimensions to predict the distribution of velocity, pressure, temperature, concentration, and other relevant variables throughout the volume. This paper presents an overview …


Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz Jun 1999

Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz

U.S. Mine Ventilation Symposium

Three mine explosions which occurred in the 1980s (1983 - McClure No. 1 Mine, Virginia; 1984 - Greenwich Collieries No. 1 Mine, Pennsylvania; and 1989- Pyro No.9 Slope Williams Station Mine, Kentucky) cost twenty lives. The authors, by investigating these three cases, found a common ventilation problem. This problem was the misunderstanding of the diagonal connections in the mine ventilation system (MVS). Based on the findings from these investigations, the authors explain the importance of diagonal connections in a MVS and discuss other factors that affected safety.


On Criteria Of Stability Of Fans Operating In Parallel, Jerzy Krawczyk Jun 1999

On Criteria Of Stability Of Fans Operating In Parallel, Jerzy Krawczyk

U.S. Mine Ventilation Symposium

Ventilation systems with fans operating in parallel may have multiple operating points. The submitted paper presents a method which enables to reduce the number of points which should be taken into consideration. The concepts of a fan system containing: the fan, inlet duct, regulation door subsystem and its total characteristics were introduced. The analysis of local stability of equilibrium points of the system of ordinary differential equations describing unsteady incompressible flow in a simplified network ventilated by 2 fans in parallel leads to formulation of a simple condition of stability. For fans operating in parallel this condition refers to the …


Optimization Of The Ventilation System At Kidd Mine Of Falcon Bridge Limited, Josef Sedlacek Jun 1999

Optimization Of The Ventilation System At Kidd Mine Of Falcon Bridge Limited, Josef Sedlacek

U.S. Mine Ventilation Symposium

Kidd Mine is the single largest producing base metal mine of Falconbridge Limited. Approximately 3 million tonnes of zinc-copper ore is produced annually. The present ventilation system, designed some 30 years ago, uses a multitude of intake and exhaust fans, in a series-parallel configuration, to move 925 m3/s (2,000,000 cfm) through the mine. The system, owing to the ever increasing depth of mining, has reached its limitation and has become cumbersome to maintain. It was recognized that with the mine progressing from the original depth of 855 m (2800 ft) to the current depth of 2070 m (6800 …


Water Injection In Longwall Top-Coal Caving Face In China, Zhang Yong, Fu Gui Jun 1999

Water Injection In Longwall Top-Coal Caving Face In China, Zhang Yong, Fu Gui

U.S. Mine Ventilation Symposium

This paper discussed the means of improving dust control efficiency using water injection. At first, the authors point out that internal water has effect on dust control. The objective of water injection is to increase the amount of internal water. Secondly, by analyzing the development trend of crack in top-coal, proper water injection station and boleholes can be determined for dust control.


Recovery Of Methane From The Abandoned Golden Eagle Mine Property, Kenton L. Hupp, Carol Bibler, Raymond C. Pilcher Jun 1999

Recovery Of Methane From The Abandoned Golden Eagle Mine Property, Kenton L. Hupp, Carol Bibler, Raymond C. Pilcher

U.S. Mine Ventilation Symposium

The abandoned Golden Eagle underground coal mine in Colorado contains gassy coals from which Stroud Oil Properties, Inc. (Stroud) has been recovering gas since 1996. The mine closed permanently in 1996, and during its operation drained methane from gob and ventilation boreholes. Stroud currently produces about 1.8 million cubic feet of near pipeline quality gas per day from six of these boreholes. Although the project has proven successful, gas recovery has been challenging because of low bottom hole pressure and variable borehole performance. Wellhead compressors are required to boost gas pressure for delivery to the main plant. Connecting additional boreholes …


Methane Drainage At The Minerales Monclova Mines In The Sabinas Coal Basin, Coahuila, Mexico, Daniel J. Brunner, Jose Ruben Ponce Jun 1999

Methane Drainage At The Minerales Monclova Mines In The Sabinas Coal Basin, Coahuila, Mexico, Daniel J. Brunner, Jose Ruben Ponce

U.S. Mine Ventilation Symposium

Minerales Monclova S.A. De C.V. (MIMOSA) operates five underground longwall mines in the Gassy Los Olmos Coals of the Sabinas Basin in the state of Coahuila in Northern Mexico. Because of high in-situ gas contents and high cleat and natural fracture permeability, MIMOSA has had to incorporate a system of methane drainage in advance of mining in order to safely and cost effectively exploit their reserves. In the early 1990s Resource Enterprises (REI) conducted reservoir characterization tests, numerical simulations, and Coal Mine Methane (CMM) production tests at a nearby mine property in the same basin. Using this information REI approached …


Proposed Regulation On Diesel Particulate Matter In Underground Coal Mines, Thomas F. Tomb Jun 1999

Proposed Regulation On Diesel Particulate Matter In Underground Coal Mines, Thomas F. Tomb

U.S. Mine Ventilation Symposium

The Mine Safety and Health Administration published a proposed rule for underground coal mines that use diesel-powered equipment. The proposed rule, published April 9, 1998, would establish new health standards. These new standards would reduce the risks to miners of serious health hazards that are associated with exposure to high concentrations of diesel particulate matter (dpm). The proposed rule would require that mine operators install and maintain high efficiency filtration systems on the most polluting types of diesel-powered equipment. The rule would also require that miners be trained about the hazards of dpm exposure. This paper reviews the requirements of …


Committees, Multiple Members Jun 1999

Committees, Multiple Members

U.S. Mine Ventilation Symposium

No abstract provided.


Published Proceedings Of The Previous Mine Ventilation Symposia, Multiple Authors Jun 1999

Published Proceedings Of The Previous Mine Ventilation Symposia, Multiple Authors

U.S. Mine Ventilation Symposium

No abstract provided.