Engineering Commons^™

Compressive And Flexural Strength Of Portland Cement Concrete As Affected By Fractured Particles Of Coarse Aggregate, Russell L. Vesper

Civil Engineering ETDs

Although a great deal of experimental data are available on many of the factors involved in a concrete mix design, a limited amount of work has been done to determine the effect of the surface characteristics of the concrete aggregates. Some research has been done in this connection by the New Mexico Highway Department. Some of the results of this research are included in a later section of this thesis.

Linear Time Base Precision And The Compound Sweep Concept, William W. Steger

Electrical and Computer Engineering ETDs

This paper is a monograph on general precision criteria for feedback linear time base circuits. The linearity and stability performance of these devices is evaluated in terms of deviation from an ideal ramp function.

In its entirety, the paper attempts to provide a complete reference for the most commonly encountered aspects of time base precision. Attention is centered on what could be called the "low frequency" case, which most often is valid in applications requiring a high precision time base.

The subject is developed in a number of progressive, cumulative stages. The end products at each stage of the analysis …

Radial Dislocations In Plane Stress., William J. Sieger

Mechanical Engineering ETDs

The elastic dislocation theory was used to obtain stress potentials for the dual dislocation problem. These solutions give the stress field for an infinite plane region containing a centrally located circular hole with two radial dislocations originating from opposite sides of the hole and extending into the region along a line perpendicular to the axis of applied load. Solutions were obtained for both the case of a linear dislocation relation along the cuts and for a parabolic relation.

A Prototype Transmitter For A Microwave Refractometer, John C. Jordan

Electrical and Computer Engineering ETDs

A study of the design, development and fabrication details of a transmitter for a microwave refractometer is presented. Atmospheric, radio frequency, refractive index is to be measured rapidly and directly up to altitudes of the order of 200,000 feet. Requirements for the transmitter with regard to its weight, volume and environment are indeed stringent since it is proposed to package the transmitter in a ogive configuration and elevate it to these altitudes utilizing a rocket propulsion system.

Complementary Transistor Memory Circuit And Logic Applications, Lee M. Bossart

Electrical and Computer Engineering ETDs

No abstract provided.

An Approach To Azimuth Angle Refraction Corrections, Wallis R. Cramond

Electrical and Computer Engineering ETDs

In the past, analyses of tropospheric reactions of electromagnetic waves propagating in the atmosphere have been based on spherically symmetric medium. However, this applies only to ray bending in a vertical plane (elevation angles). Numerous methods have been developed to correct for elevation angle errors. In 1961, the presentation of a new method for use in a nonsymmetric atmosphere revived interest in horizontal (azimuth angle) bending. In order to use this method to test significance of azimuth angle errors, the spacial distribution of index of refraction must be known.

The primary objective of this paper is to propose a model …

A Theory Of Self-Evaluating Discrete Communication Systems, Samuel D. Sterns

Electrical and Computer Engineering ETDs

No abstract provided.

Radar Back-Scatter Theories For Near-Vertical Incidence And Their Application To An Estimate Of The Lunar Surface Roughness, Harbhajan S. Hayre

Electrical and Computer Engineering ETDs

This work, after the critical examination of the theoretical background on back-scattering from rough surfaces, offers a new approach to its theory. Various back-scatter theories, as well as the statistical models of terrain and moon assumed therein, are critically reviewed and correlated. A new approach which uses a simple statistical model is then presented for the description of scattering of electromagnetic waves from a rough surface. The statistics of a rough surface are discussed in terms of certain parameters which can be easily associated the surface features, and a new expression for the back-scattering radar cross section per unit area …

Plastic Models For The Study Of Thermal Stresses, Carl W. Theisen

Mechanical Engineering ETDs

The purpose of this thesis was to determine and evaluate an experimental method for accurately measuring thermal stresses in structural shapes subjected to large transient thermal gradients, without introducing the problems of high temperature instrumentation, or expensive and elaborate test facilities. Most experimental methods consist of mounting high temperature strain gages on the prototype or model of the metal structure to be evaluated, thermal shocking the structure and then recording the accompanying strains. This method is used quite extensively in the aircraft field, and in others, where the effects of thermal stresses must be considered. However, problems are encountered when …

A System For Recording Electromagnetic Atmospheric Noise In 30-50 Cps Region, James F. White

Electrical and Computer Engineering ETDs

The electromagnetic noise spectrum extends from below 1 cps to above 3,000 mcs. Within this spectrum many phenomena of atmospheric noise have been observed. Those atmospherics which occur in the audio frequency region of the spectrum have been given not only descriptive but also subjective names by many different investigators. As a result, it is often difficult to determine from the literature what aspect of the noise phenomenon is being considered. In addition, references to low frequencies involved in certain experiments are vague. A brief history of atmospherics research is presented here in order to explain the terminology, to show …

A Study Of Gamma-Ray Photoconductivity In Organic Dielectric Materials, Stanley E. Harrison

Electrical and Computer Engineering ETDs

The gamma-ray photoconductivities of polyethylene, polystyrene, polyvinylchloride, polypropylene, Teflon, Nylon, Kel-F, and three thermosetting resins denoted as Epoxy 1478-1, 1478-3, and 1478-22 have been measured. The measurements were made at steady-state gamma-ray intensities ranging from 1.0rad(H₂O)/min to 3.0 x 10⁵ rads(H₂o)/min and at controlled temperatures ranging from 90 degrees Fahrenheit to 140 degrees Fahrenheit. Conductivity changes resulting from the steady-state gamma-ray exposures were measured continuously throughout the exposure and after the exposure. The exposure period was of sufficient duration to allow all samples to achieve an equilibrium conductivity value.

The Development Of A Static Pressure Probe For The Interaction Region Of Shock Waves And Boundary Layers, John Rode

Mechanical Engineering ETDs

The purpose of this investigation was to develop a static pressure probe for measuring static pressures in the region of interaction of a shock wave and a boundary layer. Requirements of such a probe are: small size to permit measurement of pressure variations within the thin boundary layer, pressure coefficient close to unity to permit precise static pressure measurements in regions of unknown and varying velocity and proper response to large pressure gradients.

An Evaluation Of Concrete Making Properties Of Scoria Lightweight Aggregate Based On Compressive Strength, Khurshid Ahmad Chaudhry

Civil Engineering ETDs

Compressive strength of scoria-aggregate concrete was examined by introducing controlled variables into the mix proportions. A mix design method for accurate mix design was formulated and was analyzed for consistency and feasibility.

A Qualitative Study On An Exploding Wire Fuse, W.D. Lacoss

Electrical and Computer Engineering ETDs

This study was undertaken in an effort to develop basic concepts of normal operating fuse criteria that will apply to capacitor energy storage systems. To develop ideas germane to normal fuse operating limits, it was necessary to consider certain principles that preceded this development: (1) A review had to be made of some of the experimental work on the exploding wire phenomenon to indicate a possible application as a fuse; (2) A typical circuit requiring such a fuse had to be described schematically and analyzed to show the dependency between the circuit parameters and the necessary conditions for obtaining fusing …

An Investigation Of Indeterminate Structures Stressed Beyond The Proportional Limit, Jack B. Joyce

Civil Engineering ETDs

In the structural field the methods of designing have been geared to the development of materials...In a more current appraisal we see steel and concrete being updated still further. Pre-stressed concrete is a common sight in present day construction work and, to a lesser extent, the educated eye sees rigid frames designed to ultimate load criteria. Here again are cases where materials are studied and found to possess characteristics that are adaptable to advance methods. The key to all such improvements is still the realization and utilization of material properties.

An Acoustic Simulator For Modeling Backscatter Of Electromagnetic Waves, Allen R. Edison

Electrical and Computer Engineering ETDs

Model experiments are commonly employed in situations where a full-scale experiment is uneconomical and where exact theoretical analysis is very difficult. The physical problem is scaled to convenient laboratory dimensions and a means is provided for controlling and measuring the parameters of the experiment. Measurements made in the model system are required to provide information on the time and space variations of functions which describe the real system. When interpreting results it is frequently necessary to consider "scale effects" which arise from certain parameters exerting a different influence in the model than in the real system.

Propagation Between Conducting And Nonconducting Media, Richard H. Williams

Electrical and Computer Engineering ETDs

This paper contains a study of the electromagnetic fields caused by electric dipoles located within a highly conductive medium such as the sea. The theoretical treatment of this problem was begun in 1951 with Moore's thesis. "The Theory of Radio Communication between Submerged Submarines." Some subsequent major theoretical treatments of this problem have been published by Wait and Campbell, Lien, Banos and Wesley, and Anderson. All of the above work stems from Sommerfeld's classic paper published in 1909 where he considers the fields in the air caused by a vertical electric antenna located on the interface between the air and …

An Investigation Of The Behavior Of Asphalt Stabilized Sand In Triaxial Compression Testing, Joseph P. Callahan

Civil Engineering ETDs

More and more in highway construction, the engineer is faced with the problem of locating satisfactory materials to be used in the construction of highways. This problem has become very critical in the selection of a satisfactory aggregate to be used in many phases of the construction. In large metropolitan areas and in other regions of the United States unblessed with an abundance of this aggregate, it was found that where once there was no shortage of suitable material, the supplies have now been practically exhausted.

A Study Of A Nonlinear Compensation Network In A Feedback Control System, John F. Taylor

Electrical and Computer Engineering ETDs

This paper is a study of the effect of a nonlinear compensation network on the closed-loop response of a feedback control system.

Physical energy dissipation elements, unlike their usual mathematical models, are often nonlinear. An example of such a nonlinear element is the mechanical damper. Since dissipation elements are used in most types of compensation, the problem of nonlinear compensation is an important one.

The study was performed with two goals in mind. The first was to determine the detrimental effects resulting from the insertion of the nonlinear network. The second was to see if any improvement in system performance …

A Shell-Theory Analysis Of Transient Thermal Stresses In Moderately Thick-Walled Cylinders, Thomas K. Mckinley

Mechanical Engineering ETDs

This paper investigates the validity of extending the concepts of shell theory to transient thermoelastic problems involving moderately thick-walled shells. The region of study is a moderately thick-walled cylinder which is constrained radially at both ends and is exposed to a uniform, time-dependent heating (or cooling) at one end. The cylinder walls are assumed to be adiabatic, and inertia effects are neglected in the development.

It is concluded from the results of this investigation that the extension of shell theory to moderately thick-walled cylindrical regions subjected to axial, time-dependent temperature variations is an analytical method of approach.

Analysis Of Radio Wave Propagation Over An Atmospheric Ground Layer By The Ray Tracing Method, Donnelly J. Johnson

Electrical and Computer Engineering ETDs

Previous efforts to analyze radio wave propagation in the troposphere have shown by agreement with experimental results the validity of the use of geometrical optics and the assumption of atmospheric spherical symmetry.

Evaluation Of The Thermal Properties Of Plastic Laminates, Luciano Sedillo

Chemical and Biological Engineering ETDs

To insure the proper application of newly developed materials, it is necessary to evaluate their physical and chemical properties. In the case of plastic laminates for use as heat barrier material, thermal diffusivity is an important property. Thermal diffusivity is the parameter which governs the rate of temperature change through a material. Its value depends upon the chemical composition and the physical structure of the material and its temperature.

Cerenkov Radiation From An Electron Traveling In A Circle Through A Dielectric Medium, John Joseph Newman

Optical Science and Engineering ETDs

Two hardware configurations are discussed which might be used as vehicles for checking the accuracy of the theory. It is hoped that one of these configurations might lead to a device which would yield a useful amount of power in the submillimeter region of the microwave spectrum.

An Experimental Study Of The Production Of Metallic Impregnations And Coatings -- A Vacuum Process, Engle D. Southard

Chemical and Biological Engineering ETDs

The purpose of this study undertaken was threefold, (1) to design and construct an experimental vacuum apparatus to produce a metal impregnated or coated material; (2) to study some of the variables which affect the process; then (3) to examine the physical characteristics of the resultant materials. Described herein is the development and operation of a vacuum system capable of producing conditions to permit the evaporation of metals to impregnate and coat various materials. The fundamental principle involved in this process is that a rarified atmosphere reduces the temperature required for metal evaporation and protects the metal vapor from reacting …

Comparison Of Pulse And Fm Radar Altimeters Based On Terrain Return Theory, David L. Quinlan

Electrical and Computer Engineering ETDs

In this paper a comparison of pulse of fm radar altimeters is made from the standpoint of the mathematical expressions describing each system’s return signal from terrain at near-vertical incidence. The pulse-fm radar relationships resulting from this comparison facilitates application of the extensive information gained in previous pulse radar studies to the investigation of fm radar terrain return and the associated design of fm radar altimeters, and may also assist in the development of the new pulse-type radars.

The Effects Of Operating Variables On The Adsorption Of Water From Iso-Propyl Alcohol Using Molecular Sieves, Warren P. Johnson

Chemical and Biological Engineering ETDs

The purpose of this paper is to present a study made on the effects of (1) feed concentration, (2) liquid flow rate, (3) column dimensions and (4) absorbent particle size on the selective absorption of water from iso-propyl alcohol with molecular sieves in a semi-continuous or fixed-bed operation.

A Flotation Process For The Concentration Of New Mexico Oolitic Iron Oxide Ores., William C. Rahmig

Chemical and Biological Engineering ETDs

The vast expansion in the production of steel in the twentieth century has turned the eyes of the steel industry toward sources of low grade iron ore. Evidence of this is dramatically presented in a recent issue of Steel Facts. Fifty two percent of the iron ore mined in the United States was concentrated before shipment to the consumers. This is an increase of 25 percent over the amount concentrated a decade ago. The marked increase will continue as technological advances light the way for economical are treatment.

Numerical Analysis Of The Interaction Of An Oblique Shock Wave And A Laminar Boundary Layer, James K. Cole

Mechanical Engineering ETDs

When a shock wave impinges on a boundary layer the interaction involves the continuous, viscous behavior of a boundary layer with the almost discontinuous behavior of a shock wave. A boundary layer is the region of a moving fluid that is adjacent to a solid surface. The velocity of the fluid is zero at the surface. The viscosity of the fluid causes relatively large shearing stresses in boundary layers. A shock wave is a region of a fluid which has extremely large gradients of the particle velocity. Shock waves are often rep­resented by mathematical discontinuities. A shock wave is called …

Conditional Effects In The Transistor Distributed Amplifier, Herbert D. Arlowe

Electrical and Computer Engineering ETDs

No abstract provided.

Induction Heater Temperature Controller, Raymond A. Gore

Electrical and Computer Engineering ETDs

The author was presented with a system to control the power output of a radio frequency oscillator used for induction heating. The original system was unstable. It was stabilized but even then its performance was not satisfactory. Thus the problem was to design a satisfactory system using some of the components of the old system.