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Articles 691 - 701 of 701

Full-Text Articles in Electrical and Electronics

Micro Hydro Power, Frederick J. Munster Jan 1999

Micro Hydro Power, Frederick J. Munster

Maine Collection

Micro Hydro Power

by Frederick J. Munster

Department of Economic and Community Development, August, Me. 1999 (?).

Contents: Introduction / History of Hydropower in Maine / Renewables / Why Micro Hydro / Determining Flow / Determining Head / Estimating Energy Potential / Hydro Turbines / Dams, Impoundments, Penstocks and Power Houses / Utility Interconnected Systems / Battery Charging Systems / Operation and Maintenance / Economics / Regulation of Hydro Development / For More Information / References


Fuel Cells, Frederick J. Munster Jr. Jan 1998

Fuel Cells, Frederick J. Munster Jr.

Maine Collection

Fuel Cells

by Frederick J. Munster Jr.

Edited by: Mr. Christopher Carroll

Maine Department of Economic Development, Augusta, Maine, 1998.

Contents: Hydrogen / Hydrogen Safety / Electrolysis / Electrolyzers / History of Fuel Cells / How Fuel Cells Operate / Fuel Cell Types / Fuel Cell Electrochemistry / Power Systems / Fuel Cells in Transportation / Hydrogen Powered Internal Combustion Engines / Home, Garden, Education and Industry / For More Information / Glossary / References


Micro-Electromechanical Switches For Micro-Satellite Power Transfer, Glen A. Kading Dec 1997

Micro-Electromechanical Switches For Micro-Satellite Power Transfer, Glen A. Kading

Theses and Dissertations

In the past few years, microelectromechanical systems (MEMS) have emerged as a promising new technology with tremendous application potential. One of the possible implementations of MEMS technology is in the development of micro-satellites. It should be possible to mass-produce micro-satellites at a fraction of the cost of one conventional satellite. In order for satellites to be robust, a method of transferring power to systems must be addressed. As micro-satellites are made with conventional integrated circuit technologies at a very small scale, a means of transferring power on a similar scale will be investigated. This research addresses the issue of the …


Microelectromechanical Scanner Using A Vertical Cavity Surface Emitting Laser, Joseph G. Bouchard Jr. Dec 1997

Microelectromechanical Scanner Using A Vertical Cavity Surface Emitting Laser, Joseph G. Bouchard Jr.

Theses and Dissertations

Optical scanners play a prominent role in the commercial and military industries. The scanner's size, cost and reliability are critical characteristics. In this research a microoptical scanning system was fabricated by incorporating a vertical cavity surface emitting laser (VCSEL) onto a surface machined microelectromechanical die. The micro optics for laser beam steering includes a 135 deg mirror, a Fresnel lens, a lateral scanning rotating mirror, and a vertical scanning fan mirror. The VCSEL was attached to the die by solder and electrical connection was provided by wire bonding. Based on far field measurements the scanner had a lateral scan angle …


Design And Development Of Microswitches For Micro-Electro-Mechanical Relay Matrices, Mark W. Phipps Jun 1995

Design And Development Of Microswitches For Micro-Electro-Mechanical Relay Matrices, Mark W. Phipps

Theses and Dissertations

Many different micro-electro-mechanical switches were designed in the Multi-User MEMS processes (MUMPs) and deep x-ray lithography and electroforming (LIGA) processes. The switches were composed of actuators that operated based upon either electrostatic forces or thermal forces. A thermally activated beam flexure actuator that operated based upon differential heating was used extensively. This actuator, which was fabricated in the MUMPs process, was able to deflect up to 12 microns with a total input power of less than 25 mW. The thermal resistance, which was needed to model this actuator, was determined from a material constant, 1.9 ± 0.08 m1.5-°C-W …


Study Of Single-Fiber Fiber Optic Lever Microphone, Trung Duc Nguyen Jul 1993

Study Of Single-Fiber Fiber Optic Lever Microphone, Trung Duc Nguyen

Electrical & Computer Engineering Theses & Dissertations

Fiber optic sensors are widely used in today's technological applications, providing many advantages that conventional sensors lack. In particular, there is a demand in hypersonic applications to develop microphones to measure acoustic pressure that performs in high temperature and noisy surroundings. This thesis analyzes fiber optic lever microphones (FOLM), since they perform at high temperatures. An FOLM system is an intensity modulated sensor, which is simple to implement and is small in size. Two models of the FOLM have been fabricated and calibrated. The first model uses a seven-element fiber array while the second uses a single-fiber to transmit and …


Measurement Of Thermal Noise In Condenser Microphones In A Vacuum-Isolation Vessel, Kim Chi Thi Ngo Oct 1990

Measurement Of Thermal Noise In Condenser Microphones In A Vacuum-Isolation Vessel, Kim Chi Thi Ngo

Electrical & Computer Engineering Theses & Dissertations

The electrical noise generated by thermal agitation of the air molecules impinging upon the membrane of a condenser microphone and from its associated preamplifier has been studied analytically and experimentally over a wide bandwidth. These background noise levels constitute one of the most important specifications of a microphone for they determine the lowest sound pressure that can be detected. Therefore, a new method for measuring the thermal agitation noise within a bandwidth of 1-25600 Hz has been developed. The theoretical and experimental measurements of thermal agitation noise in a condenser microphone by enclosing the microphone in a vessel which is …


Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson Oct 1990

Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson

Mechanical & Aerospace Engineering Theses & Dissertations

Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …


Saving Energy In Rural Maine : Or Who's Doing What On The Farm, Mane Department Of Agriculture Jan 1983

Saving Energy In Rural Maine : Or Who's Doing What On The Farm, Mane Department Of Agriculture

Maine Collection

Saving Energy In Rural Maine : Or Who's Doing What on the Farm

Compiled by Bettina M. Blanchard and Edited by Bill Seekins.

Maine Department of Agriculture, Food and Rural Resources, Division of Resources Development, Augusta, Maine, 1983.

Contents: List of Photographs and Diagrams / Introduction / Projects / 1. Wind / 2. Wood Heat Applications On the Farm / 3. Solar Applications / 4. Manure Handling and Waste Utilization / 5. Energy Efficient Cooling Methods / 6. Energy Saving In Field Operations / 7. Production and Use of Alternative Fuels / 8. Multi-Project Sites / Summary and Conclusions / …


Some Facts And Prospects For The Establishment Of Television Broadcasts In Mainland Tanzania, H. R. Mgombelo Dec 1979

Some Facts And Prospects For The Establishment Of Television Broadcasts In Mainland Tanzania, H. R. Mgombelo

Tanzania Journal of Engineering and Technology (TJET)

Abstract


How Electricity May Be Used To Operate Machinery, John Franklin Knowles Jan 1894

How Electricity May Be Used To Operate Machinery, John Franklin Knowles

Student and Lippitt Prize Essays

Explores the uses of electricity in a machine shop in shifting from belt and shaft systems to the use of electric plants.