Engineering Commons^™

The Effect Of Air Turbulence On The Rate Of Frost Growth On A Horizontal Flat Plate, Dennis Wayne Schulte

Masters Theses

“One factor currently affecting the efficient performance of finned refrigeration coils is frosting. This investigation determined the effect of air turbulence intensity on the growth rate of frost on a chilled flat plate in an effort to reduce the frosting problem.

Air turbulence intensities ranging from 1 to 22 percent were used with an air velocity of 590 fpm, and an air condition of 45°F and 0.0051 lb/lb humidity ratio, for the six hour tests. Additional tests at 7-8 percent air turbulence intensity were made for other air and velocity conditions.

The results showed that the effect of air turbulence …

Structure And Properties Of Neodymium Chromite, David Charles Hitchcock

Masters Theses

"Pure, accepton and Al doped NdCrO₃ were prepared by an organo-metallic process.

The crystal structure and lattice parameters were determined by x-ray diffraction. All compositions were orthorhombic Pbnm.

Pellets were pressed from powders of each composition and sintered to high density in a reducing atmosphere. When a small amount of Fe was substituted for Cr, the powder could be sintered in air.

Electrical conductivity for acceptor doped NdCrO₃ varied from about 1 (ohm cm)^-1 at room temperature to about 10 (ohm cm)^-1 at 900°C, about two orders of magnitude higher than the electrical conductivity of the …

Chemical Spray Pyrolysis Of Cadmium Telluride., Alok K. Berry

Masters Theses

"Chemical spray pyrolysis is a technique for film growth which is of interest because of its potential for very large scale, inexpensive production of polycrystalline thin film semiconductor materials. Cadmium telluride shows promise as a base material for solar cell applications. Thin films of CdTe have been spray deposited on glass substrates from an aqueous solution containing CdC1₂, Teo₂ and a reducing agent. The films show a zinc blende structure and appear to be intrinsic. Microprobe analysis indicate an excess of Cd, but this is not detectable by X-ray diffraction. The photo absorption studies indicate a direct …

Optimization Of An Investment Strategy For The Mcdonnell Douglas Salaried Savings Plan., Richard Charles Seifert

Masters Theses

"An automated technique is developed to maximize the return on investments in the McDonnell Douglas Salaried Savings Plan. Continual guidance is provided to the participant as to the currently preferred type of investment within the Plan, and to the strategic t iming of withdrawals from the Plan. The decision criteria within the modelled system address the tradeoff s which result from the participant's past investment decisions, his current tax situation, alternative market conditions, withdrawal penalties and o the r Plan characteristics. Decisions are made on the premise that historic performance patterns will continue, though adaptive procedures are included to react …

The Design And Development Of A Human Interface For An Intelligent Terminal For A Process Control Industry, V. Rangarajan

Masters Theses

"A complete description of an intelligent Terminal to be used in a Process Control Industry is presented. The system software is discussed. An account of the hardware and software interfaces for the input devices, along with the description of the input devices, is included. The data base used in the system is described with an example. Future enhancements have been proposed."--Abstract, page iii.

A Study Of The Models Describing Fines And Filler Retention By Utilizing Cationic Starch As The Retention Aid, Nen-Sen Chen

Masters Theses

Fines and filler retention under dynamic conditions was studied in this thesis work. Zeta potential of samples are also measured. Dynamic Retention/Drainage Jar and Lazer-Zee Meter were used to accomplish this work. The results have been analyzed by statistical methods. When cationic starch was utilized as a retention aid the pH affected its efficiency, probably because the charge of cationic starch was dependent on pH. This effect was detected by utilizing two-way analysis of variance to find the sources of its interactions with molecular weight and agitation rate. The mechanism was thus determined. At pH 3 and 4, charge neutralization …

Computer Aided Design For Fet Circuits, Iyad Ahmad Natour

Masters Theses

No abstract provided.

A Multiprocessor System Using A Switch Matrix Configuration, Rabah Aoufi

Masters Theses

"This thesis describes a class of interconnection networks based on the use of a switch matrix to provide processor to memory communication. This switch allows a direct link between any processor to any memory module. The cost and performance of this network are analytically examined. The results are compared with those of a multiprocessor system using a time-shared bus configuration and it is shown that for the two extreme cases of maximum and minimum throughput, the two approaches are equivalent from a performance point of view. However, in the general case, even with a higher cost, the switch matrix provides …

Properties Of High Alumina Refractories After Exposure To Steam/H₂ Atmospheres, David W. Lang

Masters Theses

"Selected properties of a dense fired alumina, a phosphate-bonded ramming mix, and a calcium aluminate cement-bonded castable were evaluated after exposure at 260°C and 538°C to steam/H₂ atmospheres (2.58, 5.17, and 6.89) MPa. Chemical reactions in the refractories were determined by x-ray diffraction, DTA/TGA, and changes in physical properties. The modulus of rupture (MOR) of the dense alumina decreased with increasing steam pressure and degree of saturation. The calcium aluminate cement phases in the castable were most reactive in 260°C steam and formed several hydrated phases which generally resulted in a higher MOR. The MOR of the ramming mix …

Calcium Migration In Dense Alumina Aged In Water And Physiological Media, Heidi H. Osterholm

Masters Theses

"The flexural strength and relative Ca concentration at the external surface were measured for a dense alumina aged in deionized water and Ringer's solution at 40⁰C for 60 weeks and at 80⁰C for 45 weeks. Changes in the Ca concentration at the external surface and flexural strength during aging were attributed to the dissolution of the calcium impurity believed to be present in a glass phase of unknown composition. Auger electron spectroscopy was used to investigate the relative concentration of the calcium impurity at the external and fracture surfaces of a dense alumina after in vivo exposure for 6, 12 …

A Study Of Mechanical Degradation Of A Coarse Aggregate Subject To Repeated Loading, Mark Alan Roenfeldt

Masters Theses

"This investigation concerns itself with the problem of mechanical degradation of a coarse aggregate and specifically as it is used as railroad ballast. Laboratory tests were used to study the aggregate with respect to its plastic deformation characteristics, the amount of degradation, changes in gradation, and the rate of change of degradation as a function of the number of load cycles.

The repeated load triaxial tests were used to study how degradation occurs with respect to aggregate gradation, relative density, and the number of load applications. The Los Angeles abrasion test was also used to determine the degradation of the …

Aerodynamic Study Of Dual Lifting Surfaces, Kamran Rokhsaz

Masters Theses

"Aerodynamic characteristics of two-dimensional dual airfoil systems have been investigated in an incompressible flow field in the area where improved aerodynamic characteristics are realized, due to the flow field coupling of the two airfoils. A simple analytic model has been developed to demonstrate some of the basic coupling effects in such systems. Laplace's differential equation for the stream-function has been solved numerically to determine the potential flow about dual airfoil geometries of different gap, stagger, and decalage. Two numerical methods have been employed; a finite-difference approach in Cartesian coordinates, for which the mixed boundary conditions have been transformed to the …

Microwave Sintering Of Batio₃ Ceramics, Kurt Duane Humphrey

Masters Theses

"Barium titanate and BaTiO₃-based multilayer capacitors were sintered in a commercial microwave oven. The oven was equipped with a 2.45 GHz continuous-wave magnetron with a maximum power output of 650 watts.

Microwave-absorbing setters made of SiC were used to offset thermal losses from the samples and allow sintering temperatures (>1325°C) to be achieved. Pure samples were pressed from commercial BaTiO₃ powder and microwave sintered to about 90% of theoretical density. Multilayer capacitors were obtained from commercial manufacturers and used in all sintering experiments. A comparison between microwave sintered material and identical samples sintered in a conventional electric furnace revealed …

Development Of An Integrated Program Of Water Reuse In A Pulp And Paper Mill, Zafar M. Chaudhri

Masters Theses

No abstract provided.

A Metallurgical Evaluation Of The Mi Vida Prospect: A Mixed Copper Sulfide-Carbonate Ore Body, Sells, Pima County, Arizona, Kevin Michael Kenney

Masters Theses

"A copper-prospect in south-central Arizona has been evaluated on a metallurgical basis. Primary chalcocite and secondary covellite, plus the copper oxides malachite and brochantite, constitute the economic mineralization. The deposit outcrops as a steeply dipping (70°SW), intensely brecciated, copper-bearing quartz vein with discontinuous lenticular ore shoots.

Acid leaching techniques alone and in conjunction with froth flotation utilizing four copper oxide specific collectors were used to evaluate the amenability of this ore to processing. Direct acid leaching was examined and found to be ineffective. Removal of the chalcocite by froth flotation with xanthate was easy and gave better results to subsequent …

Recovery Of Lead From Lead Smelter Mattes, Cheng-Ping Chang

Masters Theses

"A by-product of lead smelting is a matte which consists mostly of lead and copper sulfides. Experiments were conducted to determine the feasibility of removing lead from molten matte by adding iron as a reducing agent. The effectiveness of iron at 1000 and 1100°C was a function of matte composition, but not of temperature except near iron saturation. The lead content of matte could be decreased to as low as 9.0 to 11.6 wt pct (2.3 to 3.0 at. pct) at 1000°C, depending on composition. The effect of oxygen in the matte on lead recovery from iron-saturated mattes was also …

Pelletizing Of A Lead Sinter Machine Feed, Hung-Yang Tsai

Masters Theses

"A typical lead sinter machine feed can be pelletized in a drum pelletizer using tap water as a binding liquid. The green pellets produced have return sinter as cores, and an outer layer of new material and fluxes. The moisture content of the pellets produced is about 5%. The pelletizing procedure developed used raw materials from the Amax Lead Smelter, with only a minor amount of feed preparation. The importance of proper moisture control, use of binders, method of adding moisture, speed of pelletizing drum, etc. were investigated. The stability of pellets under extreme storage conditions was also determined"--page ii.

Development Of Impervious Low Thermal Expansion Petalite Bodies, Suchinda Chotipanich

Masters Theses

"Impervious petalite bodies were formulated from petalite, lithium aluminosilicate frit and kaolin. Thermal expansion coefficients for selected bodies were less than 2 x 10⁻⁶ /°C(20 - 600 °C). Mineralogy and the reactions in systems containing petalite, lithium aluminosilicate frit and kaolin were observed. Silica-poor high quartz solid solution was found to be the reaction product formed from the reaction between frit and kaolin before conversion to ß-spodumene solid solution at higher temperatures. The crystallization of the ß-spodumene solid solution phases in this system did not occur at the same temperature resulting in variation in the size of the crystallites. The …

Molybdenum Stability In Coal Slags At 1400⁰C: Corrosion Properties For Mhd Electrode Applications., Kenton Brian Wright

Masters Theses

"Molten coal slag corrosion studies conducted on molybdenum at 1400°C used static and stirred slag experiments and electrical current experiments to parallel electrode conditions of slagging duct MHD generators. Crucibles containing molybdenum and slag were exposed to combustion-type gases in a tube furnace. Carbon monoxide-carbon dioxide gas mixtures controlled oxygen partial pressures at selected values between 10^-11 and 10^-3 atm. Metallograph and microprobe examination of polished sample sections defined corrosion characteristics.

At 1400°C, molybdenum metal is stable below 10^-9 atm oxygen pressure. Molybdenum dioxide is stable at higher pressure, but volatile molybdenum trioxides prevent formation of stable …

Boehmite-Bonded High-Alumina Refractories, Gerhard H. Schiroky

Masters Theses

"High-alumina refractories (99+ % Al₂O₃) were produced by pressing a mixture of 70% tabular alumina and 30% reactive alumina and autoclaving in saturated steam at 1.4 MPa (200 psia)/194 °C to 3.4 MPa (500 psia)/242 °C for 12 to 96 h. Autoclaving converted the reactive alumina to boehmite which acted as the bond phase. At room temperature the MOR ranged up to 37 MPa depending upon boehmite content. The hot-MOR decreased steadily with increasing temperature, but was still 8 MPa at 1400 °C which exceeds that of comparable cement-bonded or conventionally fired high-alumina refractories. The estimated autoclaving costs are lower …

Processing Of Copper Refinery Anode Slimes, Shrirang Anant Kulkarni

Masters Theses

"A study of commercial copper refinery anode slimes has been conducted to evaluate the separation of valuable metals contained in the slimes. The slimes contain substantial quantities of Ag, Sn, Au, Pb, and Cu. The values were present principally as AgCl, SnO₂, Au, PbSO₄, Cu and CuSO₄.

A Roast-Leach-Roast-Leach (RLRL) technique solubilized up to 91 pct of the Ag and 99 pct of the Cu from raw slimes.

The Pb-Sn separation was investigated using the following hydrometallurgical techniques: 1) DETA (diethylene triamine) leaching; 2) NaOH leaching; 3) (NH₄)₂CO₃ leaching; …

Stress-Strain Properties Of Compacted Modified Memphis Loess, Danny Lloyd Kerns

Masters Theses

"A study was made of the stress-strain characteristics of compacted samples of a modified loessial soil obtained near Memphis, Tennessee. The study consisted of compacting samples at a constant water content and at unit weights of 92, 96 and 100 pounds per cubic foot (1470, 1540 and 1600 kg/m³). Triaxial tests were performed on unsaturated compacted specimens to obtain stress-strain-volume change data. These data were used to determine stress-dependent functions for tangent modulus and Poisson's ratio"--Abstract, page ii.

A Planning System For Research Management In A University Environment, Russell Lee Goldammer

Masters Theses

"The research project director at a college or university has few, if any, of the traditional management tools that are available for other forms of management, especially in performing the early, crucial stages of planning. This is particularly distressing since managing a program in this type of environment can be very difficult, due to bureaucratic red tape and interdepartmental concerns. The purpose here is to develop an aid for managers with these problems, for more effective research management in a university environment.

After developing a general model for a typical research project at a university, the Gasification Research On Wood …

The Evaluation Of Corrosion Inhibitors For Controlling Corrosion In Closed Paper Mill White Water Systems, Ifeanyi E. C. Okeke

Masters Theses

No abstract provided.

A Hydrologic Analysis Of The Meramec River Basin, Missouri, Glendon Taylor Stevens Iii

Masters Theses

"The purpose of this study was to develop water budgets for the Meramec River Basin. These budgets, developed from average annual data, are quantitative assessments of the basin's water resources.

On a long-term basis, inflow was approximately balanced by outflow indicating that the system is steady state.

Precipitation was found to be the only substantial source of inflow to the basin and averages about 40 inches per year.

Evapotranspiration was found to be the major source of outflow from the basin. Annually it accounts for about three quarters of the total outflow and averages about 30 inches.

Streamflow was found …

The Transition Of An Engineer To An Engineering Manager: The People Problem., Edward Leon Boyd

Masters Theses

“A review of existing literature and a survey of engineering managers are used to determine the work of the engineering manager, the career path leading to an engineering management position, and the skills that should be acquired by the engineer desiring to make the transition to an engineering management position.

The work of the engineering manager, like that of any manager, is getting things done through other people. In advancing to the first formal management position, the engineer usually passes through three career stages: engineer, informal manager, and formal manager. While advancing through these career stages, the engineer must increase …

An X-Ray Diffraction Analysis Of The Lacro₃-Laalo₃ Solid Solution Series, Robin Ashley Murphy

Masters Theses

"A crystallographic study was made of powders from the LaCr_1-x Al_xO₃, La_.90(Mg_.05 Cr_1-x Al_x )_.95O_2.83 , and La_1±xCrO₃ systems. The relationships between composition and thermal expansion, electrical conductivity, and vaporization were also investigated. The x-ray diffraction data of the LaCrCO₃ - LaAlO₃ compounds showed the system to form a single phase solid solution for any given sample from the series. The orthorhombic to rhombohedral phase transition was depressed to below room temperature at approximately 13% Al⁺³ substitution"--Abstract, page ii.

Utilization Of Waste Heat From The University Of Missouri Research Reactor., Anek Punyakumleard

Masters Theses

"An analysis has been conducted to determine the economic as well as technical feasibility of using waste heat from the University of Missouri Research Reactor (MURR) to heat the reactor containment building and the associated laboratory building.

Several methods of waste heat utilization were reviewed, including open field agriculture, animal shelter heating, aquaculture, waste water treatment, and space heating. Based on this review, it was concluded that several of these waste heat utilization methods are feasible for the MURR. However, the most practical means of utilizing the MURR waste heat appears to be for space heating in the reactor containment …

Development Of A Quadratic Finite Element Solution Of The Convective-Transport Equation., David A. Dillard

Masters Theses

"A quadratic finite element has been developed for the solution of the general three-dimensional convective-transport equation. Inherent instabilities in the numerical solution arise when the convective terms in the governing equation become significant. An application of upwinding techniques to the 20 degree of freedom serendipity element failed to produce acceptable results. Upwinding was applied to the 27 degree of freedom Lagrangian element with good results. Results of the latter element are given for several problems, including a model of a round to round metal forming process"--Abstract p. iii

Measurement Of Poisson's Ratio And Tangent Modulus Of A Loess, Craig Randall Bowers

Masters Theses

"A series of triaxial tests are used to develop mathematical models for tangent modulus and Poisson's ratio for a remolded loessial soil. These two models are then utilized in a finite element computer program to model the behavior of a shallow foundation placed on compacted loess. Different models for Poisson's ratio gave widely varying load settlement curves, however a constant value of .32 gave results very similar to that given by the experimentally developed model. It was found that the model developed for tangent modulus yielded unreasonable results when utilized in the finite element analysis until a limiting value was …