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Centrifugal Atomization of Lanthanide Materials for Cryogenic Coolers

Description: Until recently, Pb was the preferred heat exchanger matrix material used in low temperature cryocoolers; however, the heat capacity of Pb drops drastically below {approximately}15K and new matrix materials based on the lanthanide elements have been developed. These materials magnetically order at low temperatures and the entropy change associated with ordering contributes to the materials` heat capacities. The drawback to widespread use of lanthanide intermetallic compounds in cryocoolers has b… more
Date: January 4, 1994
Creator: Osborne, Matthew G.
Partner: UNT Libraries Government Documents Department
open access

Low frequency ultrasonic nondestructive inspection of aluminum/adhesive fuselage lap splices

Description: This thesis is a collection of research efforts in ultrasonics, conducted at the Center for Aviation Systems Reliability located at Iowa State University, as part of the Federal Aviation Administration`s ``Aging Aircraft Program.`` The research was directed toward the development of an ultrasonic prototype to inspect the aluminum/adhesive fuselage lap splices found on 1970`s vintage Boeing passenger aircraft. The ultrasonic prototype consists of a normal incidence, low frequency inspection tech… more
Date: January 4, 1994
Creator: Patton, T.
Partner: UNT Libraries Government Documents Department
open access

DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS

Description: The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might… more
Date: April 4, 2012
Creator: SEDLOCK, STEVE
Partner: UNT Libraries Government Documents Department
open access

Ag on Si(111) from basic science to application

Description: In our work we revisit Ag and Au adsorbates on Si(111)-7x7, as well as experiment with a ternary system of Pentacene, Ag and Si(111). Of particular interest to us is the Si(111)-({radical}3x{radical}3)R30{degree}–Ag (Ag-Si-{radical}3 hereafter). In this thesis I systematically e plore effects of Ag deposition on the Ag-Si-{radical}3 at different temperatures, film thicknesses and deposition fluxes. The generated insight of the Ag system on the Si(111) is then applied to generate novel methods o… more
Date: April 4, 2012
Creator: Belianinov, Aleksey
Partner: UNT Libraries Government Documents Department
open access

The Indiana Fine Arts Diagnostic Achievement Tests

Description: A document on the Indiana Fine Arts Diagnostic Achievement Tests, The Getty Center for Education in the Arts Student Assessment Meeting. The Indiana Fine Arts Diagnostic Achievement Testing program began in 1987 as a means to provide art teachers with new tools from which to measure student achievement in visual arts, music, theatre/creative drama and dance/creative movement. The purpose of the testing program is also to create / develop new tools to diagnose student and class strengths or need… more
Date: [1989-11-04,1989-11-06]
Creator: Patchen, Jeffrey H.
Partner: UNT Libraries Special Collections
open access

Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

Description: Investigations of ternary mixed early transition metal-rich sulfide and phosphide systems resulted in the discovery of new structures and new phases. A new series of Zr and Hf - group V transition metal - sulfur K-phases was synthesized and crystallographically characterized. When the group V transition metal was Nb or Ta, the unit cell volume was larger than any previously reported K-phase. The presence of adventitious oxygen was determined in two K-phases through a combination of neutron scat… more
Date: January 4, 1994
Creator: Marking, G. A.
Partner: UNT Libraries Government Documents Department
open access

Studies on the Optimization of Deformation Processed Metal Metal Matrix Composites

Description: A methodology for the production of deformation processed metal metal matrix composites from hyper-eutectic copper-chromium alloys was developed. This methodology was derived from a basic study of the precipitation phenomena in these alloys encompassing evaluation of microstructural, electrical, and mechanical properties. The methodology developed produces material with a superior combination of electrical and mechanical properties compared to those presently available in commercial alloys. New… more
Date: January 4, 1994
Creator: Ellis, Tim W.
Partner: UNT Libraries Government Documents Department
open access

An Investigation of the Influence of Initial Conditions on Rayleigh-Taylor Mixing

Description: Experiments and direct numerical simulations (DNS) have been performed to examine the effects of initial conditions on the dynamics of a Rayleigh-Taylor unstable mixing layer. Experiments were performed on a water channel facility to measure the interfacial and velocity perturbations initially present at the two-fluid interface in a small Atwood number mixing layer. The experimental measurements have been parameterized for use in numerical simulations of the experiment. Two- and three-dimension… more
Date: October 4, 2004
Creator: Mueschke, N J & Schilling, O
Partner: UNT Libraries Government Documents Department
open access

Properties of the eta prime meson

Description: The {eta}'(958) meson has been studied in the reaction K{sup -}p {yields} {Lambda}{eta}', with K{sup -} beam momenta ranging from 1.70 to 2.65 Gev/c. The Dalitz plots of {eta}' decay into {pi}{sup +}{pi}{sup -}{eta} and {pi}{sup +}{pi}{sup -}{gamma} have been examined, and from them we have determined that the most likely quantum numbers of the {eta}' are I{sup G}J{sup P} = 0{sup +}0{sup -}, although J{sup P} = 2{sup -} cannot be completely ruled out. They have also shown that the decay into {p… more
Date: June 4, 1969
Creator: Rittenberg, Alan
Partner: UNT Libraries Government Documents Department
open access

Development of odd-Z-projectile reactions for transactinide element synthesis

Description: The development of new odd-Z-projectile reactions leading to the production of transactinide elements is described. The cross section of the even-Z-projectile 208Pb(64Ni, n)271Ds reaction was measured at two new energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, seven decay chains attributable to 271Ds were observed. These data, combined with previous results, establish an excitation function for the production of 271Ds. Th… more
Date: November 4, 2004
Creator: Folden III, Charles Marvin
Partner: UNT Libraries Government Documents Department
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