Engineering Commons^™

Effect Of Excess Pbo On The Sintering Characteristics And Dielectric Properties Of Pb(Mg1/3nb2/3)O3–Pbtio3‐Based Ceramics, Jyoti P. Guha, Dyllan J. Hong, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

Additions of excess PbO to the perovskite Pb[(Mg_1/3Nb_2/3)_0.92Ti_0.08]O₃ solid solution enhanced the formation of a liquid phase at 840°C, which served as a densification aid for the ceramics. The liquid phase allowed elimination of pores and promoted grain growth during sintering. With additions of 1 to 2 wt% excess PbO, densities in excess of 97% of theoretical were obtained at a sintering temperature of 950°C. The peak dielectric constants of the resulting ceramics were over 18 000 at 30°C and dissipation factors less than 1%. Additions of PbO in excess of …

Three-Position Function Generation Of Planar Four-Bar Mechanisms With Equal Deviation Transmission Angle Control, Clark R. Barker, Gwo Huey Shu

Mining Engineering Faculty Research & Creative Works

This paper is an extension of earlier work on mapping of three-position function generation of planar four-bar mechanisms. Previously, it has been shown that all of the potential solutions to a given problem may be represented in an aft plane which can be subdivided into mechanism types. Further, the regions in the aft plane may represent two possible forms of assembly plus a change of form class which are not valid solutions. In this paper, we provide a third-order polynomial which defines the locus in the aft-plane of solutions which have equal deviation of their transmission angle from the ideal …

Disintegration Of Wood, Marian Mazurkiewicz

Mining Engineering Faculty Research & Creative Works

Disintegration of wood especially for production of wood pulp for making paper, involving subjecting a body of wood, more particularly a debarked log, to liquid jet action with the energy of the liquid as it impacts on the body such as to effect disintegration of the body into particles.

Dynamic Timoshenko Beam-Columns On Elastic Media, Franklin Y. Cheng, Chris P. Pantelides

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Differential equations, stiffness coefficients, and fixed-end forces are formulated for a Timoshenko beam-column on an elastic foundation subjected to lateral time-dependent excitations and static axial loads. The theoretical formulation includes shear and bending deformations as well as rotatory inertia, with emphasis on two approaches. The two approaches differ in terms of the assumed shear component of the static axial load on the cross section. The first approach is based on the assumption that the shear component of the axial load is calculated from the total slope; in the second approach, the shear component of the axial load is calculated only …

Condensation Method For Humidity Measurement In The Umr Cloud Simulation Chamber., Donald E. Hagen, Daniel R. White, Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Cloud Simulation Facility Has Been Developed for the Study of Various Atmospheric Cloud Processes. the Initial Relative Humidity of the Air Sample Put into the Cloud Chamber is a Key Parameter in Virtually Any Experiment and Needs to Be Known Accurately. This Report Describes How the Cloud Simulation Chamber itself Has Been Used as a Condensation Type Hygrometer to Calibrate the System's Humidifier. Two Distinct and Physically Different Methods for Inferring Mixing Ratio Are Used, One Exploiting the Sensitivity of Aerosol Activation to Humidity, and the Other Exploiting the Sensitivity of the Rate of Growth of Cloud Droplets to …

Microstructural Analysis In Processing Of The High‐Tc Superconductor Ba2ycu3o7‐X In Air, Jyoti P. Guha

Materials Science and Engineering Faculty Research & Creative Works

In the synthesis of the superconducting compound Ba₂YCu₃O_7‐x from a stoichiometric mixture containing BaCO₃, Y₂O₃, and CuO In air, a low‐melting liquid phase is formed at about 890°C. The liquid phase was identified as a ternary eutectic located within the compatibility triangle Ba₂YCu₃O_7‐x–BaCuO₂–CuO. The implication of this finding for the processing of Ba₂YCu₃O_7‐x is discussed. Copyright © 1988, Wiley Blackwell. All rights reserved.

Static Timoshenko Beam-Columns On Elastic Media, Franklin Y. Cheng, Chris P. Pantelides

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Two approaches are used to derive differential equations, stiffness coefficients, and fixed-end forces for the analysis of structural systems composed of Timoshenko beam-columns that may be supported by an elastic foundation. The analysis is for the evaluation of the critical static axial load and buckling mode-shapes of a structure with consideration of elastic media, bending, and shear deformations. The two approaches differ in terms of the assumed shear component of the static axial load on the cross section. The first approach is based on the assumption that the shear component of the axial load is calculated from the total slope, …

Three-Position Function Generation Of Planar Four-Bar Mechanisms With Equal Deviation Transmission Angle Control, Clark R. Barker, Gwo Huey Shu

Mining Engineering Faculty Research & Creative Works

In an earlier work, it has been shown that all of the potential solutions to a given problem may be represented in an αβ-plane which can be subdivided into mechanism types. Further, the regions in the αβ-plane may represent two possible forms of assembly plus a change of form class which are not valid solutions. In this paper, we provide a third-order polynomial which defines the locus in the αbeta-plane of solutions which have equal deviation of their transmission angle from the ideal of 90° throughout the entire range of motion. When these solutions are mapped into a Cartesian plane, …

Linear State Variable Dynamic Model And Estimator Design For Allison 1406 Gas Turbine Engine, Vittal S. Rao, D. Moellenhoff, J. A. Jaeger

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes a procedure for developing a State Variable Model for the Allison T406 gas turbine engine. This linear model is useful for designing controllers using modern control techniques. The engine and V-22 rotor system is modeled around an operating point by using four state variables and one input variable. For a given power setting, it is observed that two linear models are sufficient to represent the engine dynamics over the entire flight envelope. A relationship between surge margin and the state variables is also developed. It is demonstrated that these linear models are useful in designing an estimator …

Simulation Of Communication Systems Using Personal Computers, William H. Tranter, Carl R. Ryan

Electrical and Computer Engineering Faculty Research & Creative Works

Microcomputer simulation provides a powerful tool for computer-aided design and analysis of communication systems and requires a minimum of investment. Two different simulation examples are presented: a fixed topology simulation program for digital data links written in Pascal; and a simulation of an analog link using Fortran. These examples are followed by a consideration of the new 32-bit single-board computers and their potential impact on microcomputer simulation. © 1988 IEEE

A Rule-Based Dynamic Economic Dispatch For Power Systems, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

The author introduces a novel operation tool for economic dispatch. It deals with the development and implementation of a new approach-a dynamic rule-based dispatch algorithm that takes into account the major problems faced by the dispatch operator during a dispatch interval and channels those into a database for use by a rule-based system. The algorithm is very fast and can be used effectively in interconnected systems. It can also handle renewable technologies and is therefore considered useful for major electric power utilities contemplating adding a significant amount of these new generation sources to their existing mix

Packaging Engineering Education Qualitative Need Assessment, M. Douglas Sachs

Masters Theses

"Packaging engineering is an interdisciplinary field which has no formal degree program to support it. While there arc packaging engineers in industry, there are no packaging engineering degrees presently being offered by our nation's colleges and universities. In order to lay a foundation upon which a degree program could be based, this thesis has investigated the needs of packaging engineering education by seeking the input of the packaging industry. This qualitative comparison has been quantified, resulting in a list of prioritized classes and topics upon which a degree program could be based"--Abstract, page ii.

Influence Of Prior Deformation On Structure And Properties Of Heat Treated Aluminum Casting Alloy, Chungwei Hsia

Masters Theses

"A1 356 alloy is extensively used for a wide variety of casting applications. The structure is composed of primary dendrites and eutectic silicon formed during the eutectic reaction. It has long been recognized that the shape of the eutectic silicon significantly affects the ductility of the alloy. Traditionally, the morphology of the silicon is changed by certain chemical and/or thermal processes to improve the ductility. Mechanically deforming the castings to "modify" the shape of silicon has been shown by this research to be an effective alternative method to improve the spheroidization rate of eutectic silicon during heat treatment. The best …

Glass Formation And Properties In The Sm₂O₃·Al₂O₃·Sio₂ System, Erik M. Erbe

Masters Theses

"The purpose of this investigation was to develop a samarium containing aluminosilicate glass with properties suitable for use in the treatment of rheumatoid arthritis. Microspheres made from these compositions would be neutron activated to produce radioactive Sm-153 which has beta-particle energies suitable for treating rheumatoid arthritis as well as appropriate gamma-ray emission for nuclear imaging. The properties of Sm₂O₃ · AI₂O₃ · SiO₂ glasses containing 10 to 25 mole% Sm₂O₃ were evaluated as a function of composition. The density, refractive index, thermal expansion coefficient, and microhardness increased with increasing Sm …

Processing And Characterization Of Ceramic Fiber Reinforced Porous Matrix Composites, Wen-Chiang Tu

Masters Theses

"The development of ceramic fiber reinforced ceramic matrix composites has been shown to be a promising approach for high toughness ceramic materials. The purpose of this work was to develop a new ceramic matrix composite(CMC) system based on a porous mullitic matrix reinforced with ceramic fibers. Unidirectional alligned fiber reinforced mullitic matrix composites were fabricated by a filament winding process. Prepregs were laminated and thermal processed in air. SEM fractographs of the composites were characterized and related to the observed load-deflection behaviors under 3-point flexure. The fracture surface expositions changed from extensive fiber tear-out to limited fiber pull-out as the …

Effect Of Nominal Strain-Rates On The Initiation And Growth Of Adiabatic Shear Bands In Steels, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Oxygen Tension Profiles In Tumors Predicted By A Diffusion With Absorption Model Involving A Moving Free Boundary, B. H. Arve, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

The dynamic behavior of the oxygen tension distribution in tumors during radiotherapy is studied by the development and solution of a diffusion with absorption model involving a moving free boundary. The oxygen uptake rates within the tumor are considered to be functions of the oxygen concentration and results are presented for zeroth-, half-, first- and second-order rates of absorption, as well as when the rate of oxygen absorption is described by the Michaelis-Menten expression. The results presented in this work may be used together with the data from the oxygen radiosensitivity curve of a tumor, in order to determine the …

Simulation Of Photovoltaic Power Systems And Their Performance Prediction, S. Rahman, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

A number of photovoltaic (PV) performance-analysis models are tested for their ability to estimate the AC power output and validated against historical observations from a PV test facility. A method to estimate meteorological parameters is developed for use in PV performance models for predicting future AC power output from a PV test site. Twelve such PV performance models are examined, and the PVFORM system analysis program and lifetime cost and performance models are extensively tested. These two models are tested using the typical meteorological year and the VPI model-generated estimates of long-term data. Performance prediction results are compared against actual …

A Discussion On The Diversity In The Applications Of Photovoltaic Systems, S. Rahman, Badrul H. Chowdhury, M. A. Khallat

Electrical and Computer Engineering Faculty Research & Creative Works

References on the diverse applications of photovoltaic (PV) systems around the world are classified. The classes presented are (i) stand-alone, (ii) grid-connected, (iii) PV-thermal, (iv) PV-wind, and (v) dedicated applications. 73 papers are cited and classified into these five categories including a brief summary of each paper. Out of these, 42 papers relate to grid-connected applications in many industrialized countries of the world. These papers reflect the importance given to such applications. Due to the rapidly changing nature of PV and related industries, only papers published during the last ten years are considered.

Distribution Automation For The Association Of Missouri Electric Cooperatives—A Statewide Evaluation Of Load Management, Jack F. Morris, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

Presented is an in-depth technical and economic feasibility study utilizing one- and two-way management systems for statewide load control and distribution automation. Included are 1) an evaluation of the generation and transmission load patterns of the state cooperatives and the determination of the amount of controllable load for use by a load management system, 2) an in-depth economic cost-benefit study as a result of implementing a load management system on a statewide basis, 3) communication alternatives for implementing the statewide load management and distribution automation system, 4) an investigation into using an existing statewide microwave communications system for direct load …

Implementation Of Dsp Applications Using The At&T Dsp32 C Compiler And Application Library, J. Tow, J. Hartung, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

The authors briefly introduce the C compiler and the application library for the DSP32 digital signal processor (DSP). Several examples are shown that illustrate the ease of writing C programs for some common filtering applications. In most cases, a small real-time penalty is incurred by using C, rather than assembly language coding. Programming in C, however, allows a dramatic improvement in programmer productivity in terms of implementing, testing, and maintaining an application

New Directions In Subband Coding, Y. Shoham, Steven L. Grant, N. Seshadri, R. V. Cox, S. R. Quackenbush, N. S. Jayant

Electrical and Computer Engineering Faculty Research & Creative Works

Two very different subband coders are described. The first is a modified dynamic bit-allocation-subband coder (D-SBC) designed for variable rate coding situations and easily adaptable to noisy channel environments. It can operate at rates as low as 12 kb/s and still give good quality speech. The second coder is a 16-kb/s waveform coder, based on a combination of subband coding and vector quantization (VQ-SBC). The key feature of this coder is its short coding delay, which makes it suitable for real-time communication networks. The speech quality of both coders has been enhanced by adaptive postfiltering. The coders have been implemented …

Effects Of 0.5 Weight Percent Boron On Cobalt Aluminide, Kevin Thomas Slattery

Masters Theses

"A study was made on the effects of adding 0.5 weight percent boron to the ordered intermetallic Cobalt Aluninide. Thirty gram (30g) specimens were induction melted in an pure argon atmosphere and cast into a copper alloy bar mold. The addition of boron raised the modulus of rupture from 30.1 to 44.3 ksi; increased the Knoop microhardness from 543 to 693; reduced the average grain size from 190 to 70 microns; and gave a more equiaxed grain structure. X-ray diffraction detected the presence of a second phase, AlB , 12 in the material containing boron. Scanning electron micro-scopy revealed that …

Paraffin Deposition Property Measurement Using Differential Scanning Calorimetry, Kevin Lynn Thornsberry

Masters Theses

Differential Scanning Calorimetry (DSC) has been used in past studies to identify the cloud points of diesel fuels, lube oils, jet fuels etc. and it has been assumed that its application extends to all paraffinic hydrocarbons. To verify this and to investigate the possible application of Differential Scanning Calorimetry to the production phase of the petroleum industry, the onset of wax crystallization is compared with ASTM cloud point for a number of paraffinic mixtures including a variety of crude oils. Results show cloud point can be determined for crudes using DSC. Additionally, wax content can be found on a known …

Optimizing Transformer Impedance For Short Circuit Analysis, Louis Scott Becker

Masters Theses

"Transformer impedances change when the tap positions on the primary or secondary are changed. Models were designed that gave the maximum impedance variation for a large percentage of transformers studied. These models were used to study how fault currents deviated from the predicted values if the actual transformer impedance was not the same as the predicted impedance. The effects of the change in turns ratio was also taken into account, and the base voltages were chosen to be different from the transformer voltages to include this possible error.

Faults were placed on the secondary of a model radial power system, …

Behavior Of Reinforced Loess Specimens Under Triaxial Load, Mohammad Taghi Izadi

Masters Theses

"Effects of reinforcement on shear strength of a loessial (silty) soil arc studied. Unconsolidated undrained triaxial tests are performed on unreinforced and fabric reinforced soil specimens. Analyses of the test results showed that in general the shear strength of remolded loess specimens were improved substantially and increase in the shear strength was directly related to reinforcement spacing.

The mechanism of soil-reinforcement interaction and several existing analytical models are described. A modified analytical model based on enhanced confining theory is developed. This model can be used in assessing the effects of the reinforcement on shear strength of triaxial specimens. Comparison of …

Vle For 1,3-Butadiene With 1,2-Butadiene And Propyne, Patrick J. Gripka

Masters Theses

"Vapor pressures for pure 1,3-butadiene, 1,2-butadiene and propyne and 10 binary mixtures are reported at 5, 20, 35, 50, and 65°C. An equation of state utilizing saturated vapor and liquid densities is used to correlate the experimental data. Calculated relative volatilities and saturated densities are reported for the systems 1,3-butadiene - 1,2-butadiene and 1,3-butadiene - propyne. The thermodynamic excess functions Helmholtz free energy, Gibbs free energy, entropy, enthalpy, internal energy, volume, and heat capacity are derived for the equation of state and the excess properties are reported for the two systems"--Abstract, p. iv.

The Effect Of Phosphate Additives On Alumina, Alumina-Calcia, Alumina-Silica Refractory Castable Systems, Sukendro Widjaja

Masters Theses

The effects of the addition of phosphate chemicals to Al₂O₃, Al₂O₃-CaO, and Al₂O₃-SiO₂ systems have been studied concentrating on selected dry and fired properties. The various refractories evaluated were formulated from all alumina aggregate systems based on 1) a mix of tabular and calcined fine aluminas, 2) a combination of calcium aluminate cement bonded-tabular and calcined fine aluminas, and 3) an alumina aggregate-silica fume mixture. Specimens were vibration-cast, dried at 110°C and fired at 1450°C. It was found that each system has different property responses to different …

Sessile Drop Studies Of Aluminum On Sapphire, Ke Wen K. Li

Masters Theses

A sessile drop technique employing a drop placement method has been used to investigate the wetting behavior and interfacial phenomena between aluminum and single crystal α-alumina. Measurements were made under a flowing mixture of H₂ and He atomsphere from 1200°C to 1600°C. Acute contact angles decreased continuously in all cases during the 8-hour experimental time. Neither the oxygen partial pressure of the flowing gas nor the orientation of the single crystal alumina substrate affected the contact angles, but the shapes of crystals grown at the substrate-metal interfaces were dependent on the orientation of the substrate surface to some extent. …

An Experimental Study Of Adsorption And Variable Temperature Desorption Of Ethanol-Water, Propane-Propylene And Hydrogen Sulfide-Carbon Dioxide-Propane, Suvit Kulvaranon

Masters Theses

"An ideal adsorption only removes the desired components. Many times one or more other components are also adsorbed. If two or more components are adsorbed, an adsorption separation may not be satisfactory or may require additional separation procedures, even though one is highly preferentially adsorbed. In such cases it may be possible to get additional separation during the desorption stage by using variable temperature desorption.

To study such problems, two experimental apparatus were set up, one for adsorption for ethanol and water mixtures on activated carbon and silicalite, the other for propane-propylene mixtures, and hydrogen sulfide-carbon dioxide-propane mixtures both on …