Engineering Commons^™

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

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 Stochastic Model For Dielectric Breakdown In Thin Capacitors, D. A. Willming, Cheng-Hsiao Wu

Electrical and Computer Engineering Faculty Research & Creative Works

A nontrivial two-dimensional stochastic model for dielectric breakdown within a parallel plate capacitor is presented for the first time. The model has been used to determine geometric properties of parallel plate discharges. Comparisons are made between these properties and known fractal properties of electrostatic discharges within cylindrical geometries. As the spacing between the plates of a capacitor increases, the value of the fractal dimension of the associated discharge structure increases from the minimum value of unity and approaches the limiting value corresponding to the case of infinite spacing. For any given spacing, this fractal exponent is equal to the exponent …

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.

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 …

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 …

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 …

Fabrication And Mechanical Property Analysis Of A Transparent, Glass Fiber Reinforced Polymer Matrix Composite, James R. Olson

Masters Theses

"A "transparent” composite was produced by reinforcing poly(methyl methacrylate) (PMMA) with unidirectional borosilicate glass fibers. Composites with 40 volume percent fiber had a modulus of rupture of 600 MPa which is six times greater than that of pure PMMA. Young's modulus for the same composite was 18 MPA which is nine times greater than the 2 MPa measured for pure PMMA. Work of fracture was 110 kJ/m² or more than double the 45 kJ/m² required to fracture pure PMMA. The optical transmission of the composite with 30 volume percent fiber was approximately 40 percent through a 10 mm …

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.

Ion Exchange Properties Of Titania Gels Prepared From Titanous Chloride And Amonium Carbonate, Nahed Latif Yacoub

Archived Theses and Dissertations

No abstract provided.

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 …

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.

Power Filter Resonant Frequency Modulation Network, Don Cronin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A power filter resonant frequency modulation network for coupling between a load and a variable voltage direct current power source which is subjected to superposition of alternating current thereon at various frequencies and at various voltage levels, the filter including first and second series inductor arrangements in the positive and negative buses between the power supply and the load, with capacitive elements in parallel between the two buses. Each series inductor arrangement includes a first inductor in series with a frequency and voltage responsive inductive load device, which is a second inductor having a tertiary winding loaded with a coil …

Still-Frame Image Transmission Using Dpcm/Interpolative Coding, Brindala Mallappa, Norman R. Cox

Electrical and Computer Engineering Faculty Research & Creative Works

Two methods of combining DPCM (differential pulse-code modulation) and interpolation are proposed for compressing still-frame teleconferencing signals. The first method uses horizontal subsampling, DPCM, and interpolation to achieve a 4:1 compression. The other method is similar but uses vertical subsampling instead. Simulation results indicate that either method can easily achieve the required 2-b/pel data rate with negligible degradation in image quality. Conventional DPCM is shown to perform slightly better in quantitative terms when fixed-wordlength coding is used. However, the two DPCM/interpolation methods offer other advantages when used with a variable-wordlength coder

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

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.

The Distribution Of Chlorine And Iodine In Soil In The Vicinity Of Lead Mining And Smelting Operations, Bixby Area, S.E. Missouri, U.S.A., R. Fuge, M. J. Andrews, T. E. Clevenger, B. E. Davies, Nord L. Gale, C. F. Paveley, B. (Bobby) G. Wixson

Biological Sciences Faculty Research & Creative Works

Iodine and Cl are enriched in soils in the vicinity of the Magmont and Buick lead mines near Bixby, southeastern Missouri. The enrichments, up to 5.6 ppm I and 305 ppm Cl, are against regional background of 1.26 ppm I and 41 ppm Cl. The area of highest I and Cl is thought to reflect a zone of base metal sulphide mineralization occurring about 400 m below the surface. Iodine and Cl are also enriched in soils immediately adjacent to a tailings pond, hence these elements would appear to be leached from this source. A zone of enhanced I values …

Is Central Station Photovoltaic Power Dispatchable?, Badrul H. Chowdhury, S. Rahman

Electrical and Computer Engineering Faculty Research & Creative Works

An operational tool for integrating a photovoltaic system into the utility's generation mix is introduced. The development and implementation of a new approach-a dynamic rule-based (RB) dispatch algorithm-is presented. A Box-Jenkins time-series method is used to model the subhourly solar irradiance. The model is extended to yield forecast parameters which are then used to predict the photovoltaic output expected to occur at certain lead times coinciding with the economic dispatch intervals. The RB dispatch algorithm is introduced to operate as either a substitute for or an aid to the dispatch operator. It is concluded that results depend on the time …

Sealing Glasses For Titanium And Titanium Alloys, Richard K. Brow, R. D. Watkins

Materials Science and Engineering Faculty Research & Creative Works

Glass compositions containing calcium oxide, alumina, boric oxide, strontium oxide and barium oxide in various mole % combinations were studied. These compositions are capable of forming stable glass to metal seals with titanium and titanium alloys for use as seals for battery headers.

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 …

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 …

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, …

Improved Streamline-Generating Technique That Uses The Boundary (Integral) Element Method, Daopu Thompson Numbere, D. Tiab

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The boundary element method (BEM) has been used to generate streamlines for homogeneous and sectionally homogeneous reservoirs having irregular boundaries. This technique is superior to earlier methods that use 'image wells' to simulate the reservoir boundary, especially for cases where the reservoir boundary is irregularly shaped. It has wider applicability to different kinds of reservoirs and eliminates the need for trial-and-error solutions. The errors caused by discretization and numerical approximation arise on and adjacent to the boundaries only, therefore the pressures and pressure gradients on which the streamlines are derived can be calculated with very high accuracy in the interior …

An Analysis Of The Abaca Natural Fiber In Reinforcing Concrete Composites As A Construction Material In Developing Countries, Rolando V. Magdamo

Dissertations and Theses @ UNI

This study was undertaken to analyze the flexural and splitting tensile strengths and the ductility of abaca fiber-reinforced concrete composites. Abaca fibers are natural fibers of vegetable origin prepared from the abaca plant which is a native plant of the Philippine Islands. The purpose of the study was to investigate how various volume-fractions of the abaca fiber in the concrete mix could affect the mechanical properties of the concrete matrix.

A concrete design mix containing a volume ratio of 1.0 part Type I Portland...cernent and 3.0 parts sand was utilized in the preparation of laboratory test samples. Abaca fibers were …

The System Design And Evaluation Of A Microprocessor Controlled Dispenser Using A Radar Ground-Speed Sensor, Yu-Charn Chen

Dissertations and Theses @ UNI

This experimental research focused on the design of a new approach to control seed dispensers and to analyze the performance characteristics of a Doppler radar ground speed sensor for a microprocessor control dispenser. The research focused on comparing the effectiveness of using a radar unit with a fifth-wheel encoder for measuring ground speed when both were connected to a microprocessor controlled seed dispenser.

The system designed for this study consisted of hardware and a computer program in 6502 assembly language. The hardware for this study consisted of a monitor device, microprocessor control unit, stepper motor, fifth-wheel encoder, Doppler radar and …

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 …

Aircraft Vertical Profile Implementation Using Directed-Graph Methods, L. T. Brewster, Paul D. Stigall

Electrical and Computer Engineering Faculty Research & Creative Works

Aircraft Vertical Profile Simulation is Realized using a Demand-Driven Minimal-Calculation Directed Graph Structure to Reduce Calculation Time and to Force Synchronization of the Performance Measurement Functions with the System State Variables. Performance-Directed Model Adaptation Makes Dynamic Vertical Profile Path Corrections, in the Presence of Fixed Drag Variations, Possible. Drag Variations Ranging from + 10 Percent to - 10 Percent Yielded Fuel Consumption Improvements of Less Than 1 Percent in the Majority of the Cases. Calculation Time Improvement for Path Simulation Ranges from a Factor of 1.19 in the Worst Case to 1.5 in the Best Case. © 1988 IEEE