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Articles 5401 - 5430 of 5718
Full-Text Articles in Entire DC Network
The Use Of Shaped Explosive Charges To Investigate Permeability, Penetration, And Fracture Formation In Coal, Dolomite And Plexiglas, Calvin J. Konya
The Use Of Shaped Explosive Charges To Investigate Permeability, Penetration, And Fracture Formation In Coal, Dolomite And Plexiglas, Calvin J. Konya
Doctoral Dissertations
"The concentration of methane gas which exists in the exhaust air from a coal mine is critical. It can be controlled by dilution of the gas with fresh air or by the regulation of the rate of methane emission into the mine workings. Degasification techniques which control the emission rate are currently being developed. The use of shaped charges to initiate fractures in coal and increase the gas flow rate was the object of this research. The three areas of investigation were: 1) permeability changes in coal models after fracturing with shaped charge jets, 2) fracture formation in coal and …
Mathematical Modeling Of River Water Temperatures, Leland Lovell Long
Mathematical Modeling Of River Water Temperatures, Leland Lovell Long
Doctoral Dissertations
"The applicability of power spectral density techniques, Fourier series analysis, and linear regression to the mathematical modeling of river water temperature is demonstrated. Consideration is also given to the problem of estimating thermal inputs to rivers from man-made sources such as electrical power plants. First, power spectral density techniques are used in the time-series analysis of water temperature records which were taken from the Missouri River. Two spectral ranges are then studied from the standpoint of their applicability to (1) mathematical model building and (2) detection and identification of cyclic thermal inputs. Next, a Fourier regression fit to the time-series …
Statistical Studies Of Various Time-To-Fail Distributions, James Addison Eastman
Statistical Studies Of Various Time-To-Fail Distributions, James Addison Eastman
Doctoral Dissertations
"Three models are considered that have U-shaped hazard functions, and a fourth model is considered that has a linear hazard function. Several methods for estimating the parameters are given for each of these models. Also, various tests of hypotheses are considered in the case of the model with the linear hazard function. One of the models with a U-shaped hazard function has a location and a scale parameter, and it is proved in general that any other parameters in a distribution of this type are distributed independently of the location and scale parameters.
A new method used to estimate the …
The Morphology Of Cellular Precipitation In Aluminum Rich Aluminum-Silver Alloys, Santiago Ibarra Jr.
The Morphology Of Cellular Precipitation In Aluminum Rich Aluminum-Silver Alloys, Santiago Ibarra Jr.
Doctoral Dissertations
"The morphology of cellular precipitation in Al-29.8wt%Ag alloy has been investigated in bulk specimens by transmission electron microscopy and in solution treated specimens by means of hot stage microscopy. Both cellular and general precipitation were observed to occur simultaneously in quench-aged and isothermally aged alloys. By studying the early stages of precipitation in the hot stage, the mechanism for the growth of cells in Al-Ag alloys was developed. According to this mechanism, the grain boundary allotriomorphs begin to form, the boundary then interacts with the allotriomorphs by bowing, and then either trailing precipitation forms on the allotriomorphs or new lamellae …
Stratigraphy, Genesis, And Economic Potential Of The Southern Part Of The Florida Land-Pebble Phosphate Field, Dean Stanley Clark
Stratigraphy, Genesis, And Economic Potential Of The Southern Part Of The Florida Land-Pebble Phosphate Field, Dean Stanley Clark
Doctoral Dissertations
"The important and highly productive Florida land-pebble phosphate field is located in west central peninsular Florida in portions of Hillsborough, Polk, Hardee, and Manatee counties. The Pine Level phosphate area, described in detail in this report, is south of the previously known and mined deposits and occurs in portions of Manatee, Sarasota, and De Soto counties. Results of the current geologic study of the Pine Level phosphate deposit and the evaluation of the overall potential of this southern part of the land-pebble field are presented.
The entire southern part of the phosphate field is underlain by more than 15,000 feet …
Distributed-Network Realizations For The Simulation Of Partial Differential Equations, Roy Dale Hensley
Distributed-Network Realizations For The Simulation Of Partial Differential Equations, Roy Dale Hensley
Doctoral Dissertations
"A method is developed for the simulation of the partial differential equation
-uxx + koutt + klut +k2u = g(t)
for various boundary conditions. The boundary conditions are used to classify the problems into types and the Laplace transformed solution of the most general problem of each type is obtained.
Synthesis techniques are presented for the realization of circuits containing distributed networks that can be used to simulate the partial differential equation for given boundary conditions. Several heat flow and vibrating string examples are included to illustrate the application of the …
Diffusiophoretic Forces Between Juxtaposed Atmospheric Particles, Allen L. Williams
Diffusiophoretic Forces Between Juxtaposed Atmospheric Particles, Allen L. Williams
Doctoral Dissertations
"The role of diffusiophoretics and Stefan flow in droplet growth by accretion and in-cloud scavenging is examined. A calculation is made for the diffusive forces between two juxtaposed spheres one or both of which are undergoing diffusional growth and the influence of the diffusive force on the trajectories of two spheres, assumed to obey the creeping flow equations is found. The results are: a) the diffusiophoretic force between two water droplets is zero. b) the diffusiophoretic force between a spherical ice particle and a water droplet, although non-zero, is too small to appreciably influence the fall trajectories. c) the diffusiophoretic …
The Average Dissipation Curve Of An Attenuative Layered Earth Medium, Joong Hee Chun
The Average Dissipation Curve Of An Attenuative Layered Earth Medium, Joong Hee Chun
Doctoral Dissertations
"A feasible method of estimating the attenuative properties of a layered earth medium from a reflection seismogram has been developed. An average attenuation factor of n layers in the least squares sense is designated as ß and its usefulness in real applications is investigated. Techniques of extracting dissipation factors from both noise free and noisy reflection seismic traces are discussed. In order to describe the change of the factors with an increase of depth, an average dissipation curve the form of which is similar to the average velocity of layered medium is also introduced. Both the ß and the average …
The Utilization Of High Sensitivity Noble Gas Mass Spectrometry In The Detection Of Iodine-129 And Plutonium-244, Mervet S. Boulos
The Utilization Of High Sensitivity Noble Gas Mass Spectrometry In The Detection Of Iodine-129 And Plutonium-244, Mervet S. Boulos
Doctoral Dissertations
"Mass spectrometric analysis of the xenon isotopes in natural gas wells demonstrates that radioactive isotopes of element number 53 (I) and element number 94 (Pu) were present at the time of the Earth's formation. Evidence for the now extinct nuclide129I (t1/2 = 17 x 106 years) was found in CO₂ -rich gas while evidence for the now extinct 244Pu (t1/2 = 82 x 106 years) was discovered in other natural gas wells. The amounts of 129I in thyroids was measured by combining neutron activation analysis with noble gas mass spectrometry. The current …
Geochemical Anomalies In The Igneous Wall Rock At Mayflower Mine, Park City District, Utah, Zuhair Al-Shaieb
Geochemical Anomalies In The Igneous Wall Rock At Mayflower Mine, Park City District, Utah, Zuhair Al-Shaieb
Doctoral Dissertations
"Approximately 500 samples were collected from the igneous wall rock of the Mayflower Mine, Park City District, Utah. The mine is the sixth largest gold producer in the United States. The samples were analyzed for copper lead, zinc silver, manganese, sodium, potassium, calcium, magnesium and iron by atomic absorption spectrophotometry. Gold was determined by neutron activation analysis, silicon and sulfur by x-ray fluorescence spectrometery. The calculation of the mineral norm from the chemical analysis showed the wall rock to be of granodioritic composition. A study of selected vein samples indicates that the copper, silver and gold content in the veins …
Structure Of Zero Divisors, And Other Algebraic Structures, In Higher Dimensional Real Cayley-Dickson Algebras, Harmon Caril Brown
Structure Of Zero Divisors, And Other Algebraic Structures, In Higher Dimensional Real Cayley-Dickson Algebras, Harmon Caril Brown
Doctoral Dissertations
"Real Cayley-Dickson algebras are a class of 2ⁿ-dimensional real algebras containing the real numbers, complex numbers, quaternions, and the octonions (Cayley numbers) as special cases. Each real Cayley-Dickson algebra of dimension greater than eight (a higher dimensional real Cayley-Dickson algebra) is a real normed algebra containing a multiplicative identity and an inverse for each nonzero element. In addition, each element a in the algebra has defined for it a conjugate element ā analogous to the conjugate in the complex numbers. These algebras are not alternative, but are flexible and satisfy the noncommutative Jordan identity. Each element in these algebras can …
Condensation And Sublimation Of Carbon Dioxide And Water Molecules At Cryogenic Temperatures, Victor Cazcarra
Condensation And Sublimation Of Carbon Dioxide And Water Molecules At Cryogenic Temperatures, Victor Cazcarra
Doctoral Dissertations
"Measurements of the condensation coefficient of CO₂ and H₂O have been made using a molecular beam and quartz crystal microbalances. The dependence of the condensation coefficient on variables such as population density on the substrate, temperature of the substrate, molecular beam intensity and temperature of the molecular beam, was investigated. The results are explained using heterogeneous nucleation theory for low density population, and a new approach for high density population is presented. The rate of sublimation of these two gases was measured directly. The results are reported in terms of vapor pressure in the range 10⁻⁹ to 10⁻⁴ Torr. The …
The Scattering Of Elastic Waves By Void Cavities, Jerry Lee Davis
The Scattering Of Elastic Waves By Void Cavities, Jerry Lee Davis
Doctoral Dissertations
"Elastodynamic multipole theory, the theory of least squares, and the theory of integral representation of solutions are employed in solving certain problems involving an elastic solid containing a source and a scatterer. Both the source and scatterer are of finite geometrical extent; they occupy non-intersecting regions. The source is separable, i.e., its mathematical specification consists of an arbitrary vector function of position multiplied by a time function, which is further assumed to be a sinusoid. The scatterer emphasized is a finite void cavity of arbitrary shape; however, scatterers composed of rigid material may also be treated. The calculation of a …
Methods And Applications Of Systems Identification, Allen Glenn Behring
Methods And Applications Of Systems Identification, Allen Glenn Behring
Doctoral Dissertations
"A "Schmidt filter" is proposed to compute an optimal orthonormal basis for a set of "noisy" filter input functions. Procedures for determining the transfer function and inverse transfer function of the filter are given. The Schmidt filter is applied to the problem of determining mathematical models of discrete, stationary, linear, dynamic systems for the case where measurements may be corrupted by noise of unknown statistics. The identification problem is reconsidered for the case where noise and signal moments are specified. Procedures are given which insure unbiased, adaptive estimates of system order and parameters for this case. These theoretical propositions are …
An Experimental Investigation Of The Effects Of Ambient And Heated Steady Flow And Intense Sound Levels On The Response Of Acoustic Filter Elements, Raymond H. Schaffart
An Experimental Investigation Of The Effects Of Ambient And Heated Steady Flow And Intense Sound Levels On The Response Of Acoustic Filter Elements, Raymond H. Schaffart
Doctoral Dissertations
"The primary purpose of this research was to investigate the effects of flow and finite amplitude waves on the response of acoustic elements. A further purpose was to evaluate the effects of elevated temperatures and cross-sectional dimensions on element performance. As an integral part of this work various laboratory techniques were explored for their suitability.
Empirical models for the acoustic impedance of side branch resonators were developed for the two operational modes, i.e., flow past the resonator and finite amplitude wave inputs. A description of the complex variation of the acoustic resistance of the resonator with flow past and variable …
A Monte Carlo Calculation Of Neutron Reflection From Various Curved Surfaces, Charles Jack Kalter
A Monte Carlo Calculation Of Neutron Reflection From Various Curved Surfaces, Charles Jack Kalter
Doctoral Dissertations
"Plane parallel neutron beams normally incident upon the curved surface of a solid reflector are studied with the Monte Carlo method. The geometries studied are cylindrical, parabolic, and hemispherical. It is shown that when the curved surface is cylindrical, a small "focusing effect" occurs in the reflected neutron beam. Parabolic and hemispherical surfaces do not show "focusing". A study of the factors which determine the spatial dependence of the reflected flux shows that the probability of emergence of a neutron, traveling a fixed distance from a point inside the reflector, depends upon the curvature of the surface. It is only …
A Study Of Biochemical Mechanisms Involved In The Neuromuscular Blocking Activities Of Saxitoxin And Tetrodotoxin, Elwood Wilbur Hopkins Iii.
A Study Of Biochemical Mechanisms Involved In The Neuromuscular Blocking Activities Of Saxitoxin And Tetrodotoxin, Elwood Wilbur Hopkins Iii.
Doctoral Dissertations
No abstract provided.
Investigations Of The Processes Of Discoloration And Decay Of Sugar Maple, Acer Saccharum, Associated With Fomes Connatus, Terry Alan Tattar
Investigations Of The Processes Of Discoloration And Decay Of Sugar Maple, Acer Saccharum, Associated With Fomes Connatus, Terry Alan Tattar
Doctoral Dissertations
No abstract provided.
The Calculation Of Vander Waals' Constant By The Extended Hartree-Fock Wave Function, Jwe-Son Kuo
The Calculation Of Vander Waals' Constant By The Extended Hartree-Fock Wave Function, Jwe-Son Kuo
Doctoral Dissertations
No abstract provided.
Neometric Spaces, Stephen Aurom Kenton
The Diffraction Of Plane Sound Waves By A Perfectly Reflecting Quarter-Plane, Curtis Spaulding Morse
The Diffraction Of Plane Sound Waves By A Perfectly Reflecting Quarter-Plane, Curtis Spaulding Morse
Doctoral Dissertations
No abstract provided.
Study Of The Cosmic Ray Modulation With Neutron Multiplicity Analyzers, Partap Singh
Study Of The Cosmic Ray Modulation With Neutron Multiplicity Analyzers, Partap Singh
Doctoral Dissertations
No abstract provided.
Cellular Localization Of Five Exoprotein Antigens Of Staphylococcus Aureus, Isaac Albert Wamola
Cellular Localization Of Five Exoprotein Antigens Of Staphylococcus Aureus, Isaac Albert Wamola
Doctoral Dissertations
No abstract provided.
Characteristics And Purification Of Indoleacetic Acid Oxidase In Yellow Birch, Merrill C. Hoyle
Characteristics And Purification Of Indoleacetic Acid Oxidase In Yellow Birch, Merrill C. Hoyle
Doctoral Dissertations
No abstract provided.
Some Factors Affecting The Concentration And Properties Of Carrageenan In Chondrus Crispus, Stackhouse, Stephen William Fuller
Some Factors Affecting The Concentration And Properties Of Carrageenan In Chondrus Crispus, Stackhouse, Stephen William Fuller
Doctoral Dissertations
No abstract provided.
Rocket Measurements Of Field Aligned Currents And Energy Spectra Of Charged Particles In An Auroral Display, Lawrence Wah Choy
Rocket Measurements Of Field Aligned Currents And Energy Spectra Of Charged Particles In An Auroral Display, Lawrence Wah Choy
Doctoral Dissertations
No abstract provided.
The Effect Of Temperature On The Development Of Melampsorella Caryophyllacearum And The Method Of Penetration Of Stellaria Media By Thefungus, William Howard Pawuk
The Effect Of Temperature On The Development Of Melampsorella Caryophyllacearum And The Method Of Penetration Of Stellaria Media By Thefungus, William Howard Pawuk
Doctoral Dissertations
No abstract provided.
Mhd Waves Near The Magnetopause, Allan Wolfe
Mhd Waves Near The Magnetopause, Allan Wolfe
Doctoral Dissertations
No abstract provided.
Perception And Scientific Observation: A Challenge To The Assumption Of Objectivity, Raymond E. Rainville
Perception And Scientific Observation: A Challenge To The Assumption Of Objectivity, Raymond E. Rainville
Doctoral Dissertations
No abstract provided.
The Effect Of Behavioral Context On Some Aspects Of Adult Disciplinary Practice And Affect, Judith Elaine Stevens
The Effect Of Behavioral Context On Some Aspects Of Adult Disciplinary Practice And Affect, Judith Elaine Stevens
Doctoral Dissertations
No abstract provided.