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Articles 26521 - 26550 of 27312

Full-Text Articles in Engineering

32nd Rocky Mountain Conference Jul 1990

32nd Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Program and registration information for the 32nd annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, July 29 - August 3, 1990.

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Irish Building Services News Jul 1990

Irish Building Services News

Building Services Engineering

No abstract provided.

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Investigation On The Use Of Ethyl Acetate As Solvent For Seed Oil Extraction, E. L. Rivera Porras Jun 1990

Investigation On The Use Of Ethyl Acetate As Solvent For Seed Oil Extraction, E. L. Rivera Porras

Tanzania Journal of Engineering and Technology (TJET)

An investigation on the use of ethyl acetate as a solvent for the seedoil industry was carried out. As hexane is the most used solvent in extraction of oil from seeds, the study focuses on the comparison of the two solvents. The parameters studied were: contact time between solvent and seed cake, temperature of the solvent, quantity of solvent used for extraction and type of solvent. The results are presented on a relative basis where hexane is given a factor of 100. From the results obtained it can be seen that ethyl acetate is in general a better solvent than …

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Transport Matrices Of Finite Beams Resting On Elastic Foundations, M. W. Giger Jun 1990

Transport Matrices Of Finite Beams Resting On Elastic Foundations, M. W. Giger

Tanzania Journal of Engineering and Technology (TJET)

A method of derivation of the coefficients of the transport matrix for a finite element resting on one and two-parameter elastic foundation soils is outlined. The coefficients are summarized for both the Bernoulli–Euler and the Timoshenko beam model in tabular form, for general reference. In addition, bounds on the parameters describing beam/soil flexure, beam and soil shear, which govern the validity of the two-parameter elastic solutions are provided in graphical form.

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A Study Of Load Bearing Capacity Of Piles Driven In The Zanzibar Harbour Submarine Soils, A. M. Dubi Jun 1990

A Study Of Load Bearing Capacity Of Piles Driven In The Zanzibar Harbour Submarine Soils, A. M. Dubi

Tanzania Journal of Engineering and Technology (TJET)

The rehabilitation of the Zanzibar Port involved, among other things, driving piles into the submarine soils. Pile driving fractures the coral and as a result creates a gap filled with loose fractured coral between the unfractured coral and the pile. Grouting of the external surface of the pile is done to strengthen the fractured coral. In this paper, two grouted working piles (TP6 & TP61), randomly chosen from the pile group, were load tested to twice the design load. The test results indicate adequacy of the bearing capacity of the grouted piles.

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Force Displacement Relationship For The Prediction Of Structural Fluttering, Ladislaus Lwambuka Jun 1990

Force Displacement Relationship For The Prediction Of Structural Fluttering, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

A new presentation of force displacement relationship for the prediction of structural fluttering is discussed in this paper. This topic is limited to a detailed discussion of the derivation of the equations of motion for the rigid streamlined airfoil/flat plate system of three degrees of freedom, which yields expressions for aerodynamic resultant forces due to a steady air flow. The equations of motion presented herein are derived from the conventional classical complex presentation transformed into real matrix equations. This new presentation of the equations of motion constitutes the foundation for the latest state-of-the-art of predicting critical wind loads on the …

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Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja Jun 1990

Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

A numerical method for solving two dimensional elliptic boundary-value problems of fourth order is used for finding stationary solutions of the equations of motion for a laminar flow through a sudden pipe expansion of an incompressible non-Newtonian fluid with a constitutive equation of the Reiner-Rivlin (R-R) type. Results for the Newtonian fluid, which is a special case, are in excellent agreement with those by previous investigators and they demonstrate the reliability, superiority and accuracy of the method. Results for the non-Newtonian cases could be of value for fixing ideas about visco-elastic behaviour although the R-R fluid allows only inelasticity: this …

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Healthcare Management: Operation Research Perspectives, Basu Ghosh Jun 1990

Healthcare Management: Operation Research Perspectives, Basu Ghosh

IIMB Management Review

No abstract provided.

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Freight Transport Management In India Railways Through Improved Wagon Utilization, T Krishna Kumar, D M Pradyumna, R D Saklani Jun 1990

Freight Transport Management In India Railways Through Improved Wagon Utilization, T Krishna Kumar, D M Pradyumna, R D Saklani

IIMB Management Review

Application of management concepts and tools to the service sector, particularly in the public sector, is of very recent origin. Such applications to rail freight transport, particularly in developing countries, are very few. This paper presents such an application to the problem of freight transport management in Indian Railways. The problem considered is that of efficient utilization of the scarce rolling stock -wagons. The plan of the paper is as follows. Section 2 gives a brief background of Indian Railways. A brief review of freight management models is presented in Section 3. The same section also gives a description of …

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Application Of Fuzzy Set Technique To Agricultural Planning, S Kumar, Narasingh Misra, B C Ghosh Jun 1990

Application Of Fuzzy Set Technique To Agricultural Planning, S Kumar, Narasingh Misra, B C Ghosh

IIMB Management Review

In India, agriculture remains the dominant sector of economic activity with 74 percent work force depending on it. But the share of income from agriculture sector is less than the employment in it. Also the menace of unemployment and food requirement is increasing with growing population. Hence , there is a great need for increasing production and net profit levels on one hand and employment generation on the other. Irrigation planning plays an .mportant role in increasing agricultural production, net benefit, employment generation etc. as only 32 percent of the total cultivated area is irrigated in our country. Irrigation Planning …

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Safety Economic And Strategic Issues Of Indian Nuclear Power Programme, V Ranganathan, Sanjay Kanoongo Jun 1990

Safety Economic And Strategic Issues Of Indian Nuclear Power Programme, V Ranganathan, Sanjay Kanoongo

IIMB Management Review

No abstract provided.

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Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave Jun 1990

Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave

RISK: Health, Safety & Environment (1990-2002)

After examining and analyzing the experience with coke ovens, the authors conclude that attempts to force technology beyond its demonstrated competence can be both expensive and ineffective in controlling hazards. They also suggest implications for pending proposals to further control air pollution.

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Irish Building Services News Jun 1990

Irish Building Services News

Building Services Engineering

No abstract provided.

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Irish Building Services News May 1990

Irish Building Services News

Building Services Engineering

No abstract provided.

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Ole Miss Engineer 1990 Apr 1990

Ole Miss Engineer 1990

Ole Miss Engineer

No abstract provided.

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Irish Building Services News Mar 1990

Irish Building Services News

Building Services Engineering

No abstract provided.

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Irish Building Services News Feb 1990

Irish Building Services News

Building Services Engineering

No abstract provided.

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Risk Objectivism And Risk Subjectivism: When Are Risks Real, Paul B. Thompson Jan 1990

Risk Objectivism And Risk Subjectivism: When Are Risks Real, Paul B. Thompson

RISK: Health, Safety & Environment (1990-2002)

Typically, those who discuss Risk management envision a two-step process wherein, first, Risk is more or less objectively appraised and, second, the acceptability of those Risks is subjectively evaluated. This paper questions the philosophical foundations of that approach.

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Increasing The Practical Resolution Of Projection Lithography Using A Phase-Shifting Mask, Eric M. Apelgren Jan 1990

Increasing The Practical Resolution Of Projection Lithography Using A Phase-Shifting Mask, Eric M. Apelgren

Journal of the Microelectronic Engineering Conference

A phase shifting mask, to be used for the purpose of improving the resolution of a projection lithography system, was fabricated. This type of mask consists of line-space pairs in which every other aperture induces a 180 degree phase shift in the transmitted radiation. In order to obtain this phase shift there must be a thickness difference between the apertures. Etching of the glass mask plate in 3:100 HF to DI water was used to obtain the required • etch depth.

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Bilayer E-Beam/Duv Resist Systems, James Baccaro Jan 1990

Bilayer E-Beam/Duv Resist Systems, James Baccaro

Journal of the Microelectronic Engineering Conference

Two bilayer E-beam/DUV resist schemes were developed using a DUV sensitive PMGI planarization layer and two E-beam sensitive imaging layers. PMM~ and Olin-Hunt Waycoat HEBR-214 were used as imaging layers. The HEBR-214/ PMGI system is totally aqueous developable. Both systems offer several advantages over other bilayer systems including thermal stability, low interfacial - layer formation, and low toxicity.

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Micromachining: The Fabrication Of A Micromotor, Brian C. Barker Jan 1990

Micromachining: The Fabrication Of A Micromotor, Brian C. Barker

Journal of the Microelectronic Engineering Conference

Micromachining techniques were used to fabricate two versions of a small electromechanical device, a Micromotor. This structure, originally developed by a pair of graduate students at the University of California at Berkeley, then modified by a fifth year student a Rochester Institute of Technology, was formed through multiple polysilicon depositions. After an etch of approximately two hours, the rotors were shown to have released, and moved by mechanical means, however, movement was not achieved through electrical means.

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Reactive Ion Etching Of Silicon Dioxide Using Both Oxygen And Carbon Dioxide As Gas Additives, James E. Constantino Jan 1990

Reactive Ion Etching Of Silicon Dioxide Using Both Oxygen And Carbon Dioxide As Gas Additives, James E. Constantino

Journal of the Microelectronic Engineering Conference

A study was performed on the etch characteristics of silicon dioxide and polysilicon for a reactive ion etch system, using CHF4 as the primary etchant gas and using either oxygen or carbon dioxide as an additive gas. Correlations were found between the amount and type of additive gas introduced to the system, the Rf power of the - system, the pressure that the system is maintained at and the effects these parameters have on the etch rate and - selectivity of Si02 and polysilicon etches. It was found that adding CO2 in small amounts to the gas mixture instead of …

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Design And Construction Of A Step Etching Instrument, Robert L. Crandall Jan 1990

Design And Construction Of A Step Etching Instrument, Robert L. Crandall

Journal of the Microelectronic Engineering Conference

An instrument was designed and constructed to perform a sequential etch of an oxidized silicon wafer by periodically lowering the wafer deeper into an etch bath. The unit will step the wafer at four different time intervals 15, 30, 45 and 60 seconds. Either five or ten steps can be done at one time. The unit is primarily designed for the etching of silicon dioxide in a Buffered Oxide Etch.

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Investigation Of Process Induced Defects Using A Lto Process, Joseph Desantis Jan 1990

Investigation Of Process Induced Defects Using A Lto Process, Joseph Desantis

Journal of the Microelectronic Engineering Conference

The effects of process induced defects, such as dislocations and/or oxide induced stacking faults, were investigated for a bipolar process employing solid diffusion sources. Carborundum BN975 Boron Sources have a low temperature oxide (LTD) step to minimize defects. Two bipolar processes, one with and one without LTD were run and electrical tests done to evaluate device characteristics. ~t this point results were inconclusive.

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Polysilicon Vs. Aluminum Gate Pmos Ring Oscillators, Kurt E. Gerber Jan 1990

Polysilicon Vs. Aluminum Gate Pmos Ring Oscillators, Kurt E. Gerber

Journal of the Microelectronic Engineering Conference

A nine stage PMOS ring oscillator was designed using polysilicon gates for a self-aligning process while another was designed using a standard metal gate process. A comparison of the polysilicon and metal gate PMQS processes was planned to show the reduced gate capacitance of the self-aligning process. This reduced gate capacitance was to be observed by measuring and comparing the propagation delay of each design on the oscilloscope.

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A Diagnostic Test Chip For Nmos Processing, William Gross Jan 1990

A Diagnostic Test Chip For Nmos Processing, William Gross

Journal of the Microelectronic Engineering Conference

Novel test chip structures isolating process problems in certain device regions were designed in area ratios of lx,4x, and 16x in order to investigate sizing trends. The upper three levels of an NMOS process (poly, dielectric, and metal) were fabricated. Metal line integrity structures were tested on a pass or fail basis. Results show that problems did occur in the metal patterning steps causing shorts between adjacent lines. The actual processing steps (photolithography or etching) that were responsible could not be determined without much further testing.

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Design And Construction Of A Noncontact Resistivity Measurement Instrument, William R. Hamilton Jan 1990

Design And Construction Of A Noncontact Resistivity Measurement Instrument, William R. Hamilton

Journal of the Microelectronic Engineering Conference

An Eddy—Current Gauge was fabricated from the design of G. L. Miller, D. A. H. Robinson and T. D. Wiley Cl]. The electronics involved was mounted on a printed circuit board and the header assembly was successfully machined and housed in Lucite. The calibration and testing confirmed the instrument’s linear properties for measuring conductivity.

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The Impact Of Submicron 10x Reticle Defects On Images Printed With A 0.28 Na G-Line Stepper, Karl D. Hirschman Jan 1990

The Impact Of Submicron 10x Reticle Defects On Images Printed With A 0.28 Na G-Line Stepper, Karl D. Hirschman

Journal of the Microelectronic Engineering Conference

A lOX reticle was produced with programmed defects of both polarities varying size, proximity to adjacent features, and feature sizes. The defects were imaged in various resist materials over silicon, silicon dioxide, silicon nitride, polysilicon, aluminum, and a 1X chrome mask using a GCA/Mann 4800 stepper. Results obtained using optical and scanning electron microscopy demonstrated that reticle defects as small as 1.0 micron, when in proximity to a feature, will cause linewidth variation in the printed image. The resist film and underlying substrate did affect the linewidth variation. Defocus and over/under exposure also influenced the severity of damage created by …

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Capacitance-Voltage Characterization For Polysilicon Gate Mos Capacitors, Brian Izzio Jan 1990

Capacitance-Voltage Characterization For Polysilicon Gate Mos Capacitors, Brian Izzio

Journal of the Microelectronic Engineering Conference

The effects of an n-type and p-type doped polysilicon gate fabricated over both an n-type and p-type substrate for MOS capacitors with different polysilicon doping processing schemes was evaluated and compared to the current RIT process that utilizes a metal gate. Both boron and phosphorous Spin on dopants were used to supply the conduction for the gate region of the polysilicon capacitors. Bias temperature bias was performed to evaluate the mobile ion contamination non-ideality, while a FORTRAN program was written to extract important capacitance voltage parameters from the actual C-V plots obtained that are of interest for MOS technologies

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The Affects Of High Temperature Steps On Bow, Warp And Slip Of A Wafer, Mark Klare Jan 1990

The Affects Of High Temperature Steps On Bow, Warp And Slip Of A Wafer, Mark Klare

Journal of the Microelectronic Engineering Conference

Bow, Warp and Slip measurements were used to characterize push/pull rates of a three inch oxidation furnace. The push/pull rates were varied from 3 to 30 inches per minute. To minimize the amount of bow, warp, and slip while still being time efficient, recommended push rates of 12 and pull rates of 3 in/mm should were found.

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