Engineering Commons^™

Design And Operation Of A Microprogrammed Branch Driver For A Pdp-11 Computer., Lavon R. Biswell

Electrical and Computer Engineering ETDs

A Microprogramned Branch Driver (MBD) is the interface between Digital Equipment Corporation (DEC) PDP-11 series computers and a multicrate CAMAC system. The MBD is a microprocessor-controlled multiple, direct memory access (DMA) channel branch driver.

The requirements for an MBD are discussed in the introduction and stem from a Los Alamos Scientific Laboratory (LASL) study group report on the design of the Clinton P. Anderson Meson Physics Facility (LAMPF) data acquisition system. Because of the desire for the standard system, the types of experiments and data rates, and the varying complexity of the data acquisition systems, it was decided that a …

A Probabilistic Approach To The Design Of Heat Pipes, Charles C. Roberts Jr.

Mechanical Engineering ETDs

The design of heat pipes involves knowledge of phenomena such as surface tension forces, wick permeability, and fluid vaporization and condensation. Considerable variability in these phenomena has been observed in heat pipe experiments. Thus, a probabilistic design model for predicting heat pipe heat transfer rate has been developed taking into consideration uncertainty in the prediction of the above phenomena. The probabilistic model yields a mean, a standard deviation, and the distribution of heat transfer rate based on the means, standard deviations, and distributions of the design parameters. The probabilistic method is compared to experimental data from heat pipes with wire …

Elastic-Plastic Poisson's Ratio Of Borsic-Reinforced Aluminium Composites, Ronald Edward Allred

Nuclear Engineering ETDs

Poisson's ratio as a function of tensile strain has been examined for four volume fractions of unidirectional Borsic-reinforced aluminum composites. Linear relationships were found between Poisson's ratio and fiber volume fraction during Stage I (elastic filaments-elastic matrix) and Stage II (elastic filaments-plastic matrix) deformation which confirms that rule-of-mixtures equations may be used to predict Poisson's ratios for metal-matrix composites. These equations must be used with care, however, due to differences in the Poisson's ratio behavior of the components of the composite when tested alone and in situ in the composite. These differences are attributed to the triaxial stress field generated …

The Effect Of Porosity On Transverse Tensile Strength Of Filament Wound/Cvd Carbon-Carbon Composites., Gilbert William Brassell

Nuclear Engineering ETDs

Filament wound/CVD (Chemical Vapor Deposition) carbon­carbon composites have received considerable attention within the past few years due to desirable characteristics such as high heat of ablation, thermal shock resistance, strength improvement at elevated temperatures, and chemical inertness. However, poor mechanical properties in the trans­verse direction have hampered the total effectiveness of these composites in some applications and a study of the effects of porosity on transverse tensile strength of filament wound/CVD carbon carbon composites has been conducted.

Two types of filament wound/CVD carbon carbon composites were studied. A standard filament wound/CVD carbon composite, and a composite similar to the standard …

Kinetics And Dynamics Of Continuous Crystallization, Karichangal C. Parthasarathy

Chemical and Biological Engineering ETDs

A design correlation is presented for the prediction of steady state product size distributions resulting from a continuous crystal­lizer, based upon a single experimental determination. This has been accomplished by the definition of a new parameter called the "degree of crystallization," which has been related to the experimental nuclea­tion and growth rates in a salting-out crystallizer. The correlation resulted from the detection of variations in the suspension density of the mother liquor which has previously been assumed constant in cer­tain power law models. The degree of crystallization has also been described in terms of dimensionless number, length and area moments …

Continuous Crystallization Of High Explosives, Larry E. Hatler

Chemical and Biological Engineering ETDs

Nitroguanidine (NQ) is a high explosive which is commercially available in low bulk density form (0.20 to 0.30 gms/cm³). This low bulk density limits its usefulness as an explosive. High bulk density NQ can be produced from a NQ-N, N-dime-thylformamide-Versamid 125 system when crystallized in a mixed suspension mixed product removal crystallizer. Bulk densities ranged from 0.92 to 1.05 gms/cm³ for the operating conditions used. The effect of agitator speed, growth rate, and solids concentration on nucleation rates was determined using a multiple linear regression technique. The resulting equation is: B₀ = 0.19 (RPM) ^1.54 (G) …

A New Optimization Procedure For Digital Simulation, Donald Howard Schroeder

Electrical and Computer Engineering ETDs

The theory needed to define and obtain an optimized digital simulation of a given continuous system is presented in this dissertation. The frequency domain approach to simulation is used and a nonlinear function minimization algorithm, implemented on a digital computer, is incorporated to obtain the optimum simulation.

The discrete transfer function obtained from z-transform theory is used to represent the digital system. The frequency domain response of this discrete transfer function can then be expressed simply as a function of frequency, for frequencies up to one-half the sampling frequency. A frequency domain error measure, in the complex plane, is defined …

Dispersion In Laminiar Flow Of Non-Newtonian Fluids, Subhash N. Shah

Chemical and Biological Engineering ETDs

In the present investigation, Taylor's analysis of the dispersion of solutes in laminar flow of a Newtonian fluid through a circular tube was extended to the case of a non-Newtonian Eyring model fluid. A new approach was taken to solve the convective diffusion equation for the Eyring model fluid. This approach incorporates the use of the dimensionless longitudinal pressure gradient and the mean velocity to obtain the dimensionless concentration. Using an approach similar to that of Taylor, a solution of the diffusion equation was obtained for quantities such as the dimensionless concentration, mean concentration, and effective dispersion coefficient as a …

Gallium-Arsenide-Phosphide Mis Capacitor Fabrication And Radiation-Effects Studies, Douglas H. Phillips

Electrical and Computer Engineering ETDs

GaAsP MIS capacitors were fabricated using several dielectric-growth processes, including RF sputtering, wet oxidation, and dry oxidation of GaAsP. Dry oxidation of GaAsP surfaces produced MIS devices having the best charac­teristics. Instabilities of early MIS capacitors were over­come by use of thermal cycling techniques and chromium-doped dielectrics. Deep-depletion characteristics were observed for GaAsP MIS C-V curves, even in the range of applied bias which theoretically should result in inversion of the GaAsP surface. Both low-frequency and high-frequency C-V data support the conclusion that inversion characteristics were not observed for GaAsP MIS capacitors. Calculated high-frequency surface-state density and surface-state charge values …

Low Temperature Investigations On Epitaxial Silicon Using The Micro-Hall Device, Joseph P. Baca

Electrical and Computer Engineering ETDs

This report is concerned with the feasibility of using the micro-Hall device, introduced by Colclaser and Southward, as a tool for determining important electrical characteristics of epitaxial silicon at low temperatures. The theory of carrier concentration and mobility as a function of temperature in the low temperature range is presented. A contact diffusion mask is introduced which eliminates the formation of an unwanted junction at the substrate contacts and aids in the formation of ohmic contacts. The refrigerator (cryo-tip) used to obtain low temperatures and a special designed specimen holder which connects to the cryo-tip are described.

Dynamic Response Of Predictions Of Reinforced Concrete Beams, Lawrence D. Reaveley

Civil Engineering ETDs

Prediction of the dynamic response of reinforced concrete beams by various analytical model techniques was considered. Four models were studied: (1) an elastic or elasto-plastic SDF model, (2) an SDF model based on experimental force-displacement data, (3) an SDF model based on a theoretical moment-flexural rigidity relationship, and (4) an MDF model based on a theoretical moment-flexural rigidity relationship.

Beam response, as predicted with the various models, was compared to experimental response data obtained from simply supported, singly reinforced, concrete beams. Static and dynamic response was considered. Dynamic model modifications for the stiffness, yield strength and damping were studied. Nominal …