Engineering Commons^™

Noise Description And Noise Control At The Federal, State, And Local Level, Bobby L. Henning

Retrospective Theses and Dissertations

Noise, that undesirable portion of the ever-present sounds of our environment, has until the last decade, been considered as an unavoidable by-product of our rapid population growth and its accompanying mechanization. As awareness of adverse health effects from noise exposure grew, the Federal government, as protector of the public health and welfare, took the initial steps to control noise pollution. Federal legislation, beginning with the Clean Air Amendments of 1970, has been promulgated to control major offenders and to assist State and local governments in their endeavors to provide the public with an environment free from harmful noise levels. This …

Statistical Fading Of A Spherical Optical Wave In Atmospheric Turbulence, Lorraine M. Locke

Retrospective Theses and Dissertations

A formula for the average fade time of the intensity of a spherical optical wave travelling through atmospheric turbulence is developed. The model employed involves isotropic, homogeneous statistics using a lognormal distribution for the channel. The analysis is based on the fact that the logarithm of the irradiance is normally distributed and uses the work of S. O. Rice who developed such an expression for a zero mean, Gaussian process. The analysis employs the covariance function and the Taylor frozen turbulence hypothesis which results in an expression for the autocorrelation function.

Speed Control Of Dc Shunt Motor For Electric Car Use, Mahmood Shahi

Retrospective Theses and Dissertations

This report describes the speed characteristic and various methods of speed control of DC shunt (separately excited) motors, especially for application in electrical vehicles. The basic behavior of the DC motor is discussed, along with traditional and modern techniques of speed control. As an example, a speed controller for a shunt motor (built and tested by the author) is discussed. Two types of speed controllers for electric cars are discussed, and the performance results for an experimental electric car are presented. Finally, a design for a 24 HP car motor controller using both armature and field control was simulated on …

Electromagnetic Wave Scattering From A Rough Surface, Elie G. Nacouzi

Retrospective Theses and Dissertations

This was a study to measure surface roughness using scattering of electromagnetic waves in the Ka and X microwave frequency bands. The detected fluctuations of the reflected field intensity is a measure of surface roughness. The reflected field intensity depends on the wavelength, the angle of incidence and the electrical properties of the media. Since the surface presents irregularities with randomly distributed facets, the characteristics of the rough-surface reflected wave can only be described by the statistical properties of the field intensity. The dependence of the normalized moments of the returned scatter on distance from the rough surface to the …

An Investigation Into The Solution Of Three Dimensional Elastostatic Problems Using The Boundary Integral Technique, David Campbell Aldrich

Retrospective Theses and Dissertations

The boundary integral technique was implemented in a computer code for the general static analysis of three dimensional elastic solids. The was based on a formulation of the problem in which the governing boundary equation is developed from the known solution to Kelvin's problem, by the application of Betti's reciprocal relationship. Modeling the boundary of the region being analyzed with plane elements and assuming the tractions and displacements constant across these elements leads to a set of simultaneous algebraic equations approximating the boundary integral equation. Numerical techniques are used in the computer code to assemble and solve this set of …

Fade Time Statistics Of Laser Light Propagating Through Turbulent Atmosphere, Madjid A. Belkerdid

Retrospective Theses and Dissertations

The average fade time of the fluctuations in the intensity of laser light propagation in the atmosphere is analyzed. Experimental results show that the average fade time for a propagation distance of 208 meters, in the weak turbulence regime, is well described by formulas developed from a Log-Normal distribution. A circuit that calculates real time statistics of fade time is designed, then validated using a sine wave input whose fade time statistics are predetermined. The experimental signal is then tested for stationarity, and the average fade time is measured. A curve fitting is then performed for the experimental data and …

Design And Analysis Of An Explosive Driven Hydrodynamic Conical Shock Tube, Leonard W. Connell

Retrospective Theses and Dissertations

An explosive driven, water filled, conical shock tube was designed and evaluated regarding its ability to amplify a charge weight and to produce hydrodynamic spherical shock waves. The results show that the shock waves in the tube are essentially spherical in nature--with an initial exponential shape, peak pressure attenuation as (1/R)1.13 and the time constant spreading roughly as (R).22. The charge weight was amplified by a factor of 3600 compared to a theoretical amplification of 7770. An estimate of the energy absorbed by the breach plug (which houses the charge) during an explosion was performed. The peak pressure data taken …

Nominal Molecular Weight Distributions Of Color, Toc, Tthm, Precursors And Acid Strength In A Highly Organic Potable Water Source, Jalil Fouroozi

Retrospective Theses and Dissertations

This research investigated the relationships between molecular size and the TOC, TTHM, acid strength and color concentrations present in raw and coagulated water from Lake Washington. Three separate coagulants were utilized for investigation. There were: Al, Fe and Mg. Results indicated that the majority of the TOC, color and TTHM precursors were in the colloidal size range and removed by coagulation. The remaining TTHM precursors are mostly molecular and require a process other than coagulation for removal from the potable water before environmental standards are met.

A Ten Kilometer Transmission System Fiber Optics Versus Ku-Band, John A. Hallmark

Retrospective Theses and Dissertations

This research paper discusses the design evaluation and selection of a transmission system to be used in checking out the Spacelab high rate data system. The transmission systems evaluated are discussed, as well as the criteria utilized in selecting the final system. The installation of a fiber optics cable and the testing of this cable are discussed. The determination of the optimum location of the high rate data bit synchronizer and Viterbi decoder is presented. Utilization of this data to justify the installation of a shorter fiber optics system inside the O&C Building is presented.

Statistical Fading Of A Plane Optical Wave In Atmospheric Turbulence, John F. O'Hara

Retrospective Theses and Dissertations

A formula for the average fade time of the intensity of a plane optical wave traveling through atmospheric turbulence is developed. The model employed involves isotropic, homogeneous statistics using a lognormal distribution for the channel. The analysis is based on the fact that the logarithm of the irradiance is normally distributed and uses the work of S. O. Rice who developed such an expression for a zero mean, Gaussian process. The analysis employs the covariance function and the Taylor frozen turbulence hypothesis which results in an expression for the autocorrelation function.

A Monte Carlo Approach To Ridge Discriminant Analysis, Lee Wooldridge

Retrospective Theses and Dissertations

A combined analytical and empirical method to define human performance measures is required for effective automated training. In theory, performance measures can be weighted and combined in a single first order equation upon which an automated training system can track a student's comparative skill level. A form of multivariate discriminant analysis was the statistical technique incorporated into the measurement selection and weighting scheme. (Vreuls and Wooldridge 1977). As with regression analysis, this discriminant technique was subject to debilitating problems such as overfit and undesirable inaccuracies in the coefficients. The author developed and implemented an adjustment to the discriminant function analogous …

The General Purpose Interface Bus, Ernest D. Baker

Retrospective Theses and Dissertations

The General Purpose Interface Bus, as defined by the IEEE Standard, deals with systems that require digital data to be transferred between a group of instruments. An overview of this standard is presented which summarizes the interface's capabilities, functions and versatility by explaining the basic interface concepts. In addition, a GPIB testing application and a GPIB related design example are presented and investigated.

Thermosiphon System, Florida Solar Energy Center

FSEC Energy Research Center®

In a THERMOSIPHON SYSTEM, cold water from the bottom of the elevated storage tank flows to the lowest point in the system (which is the bottom of the solar collector).

As it is warmed it becomes less dense and flows up to a side port near, but not at, the top of the storage tank. If the tank is about two feet above the top of the collector, the system will not back-siphon at night. If back-siphoning were to occur, the warm water would be cooled during its passage through the dormant collector. Thermosiphoning systems have no moving parts and …