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Application of the Environmental Protection Agency`s data quality objective process to environmental monitoring quality control

Description: The United States Environmental Protection Agency`s (EPA) Data Quality Objectives (DQO) process was applied to two environmental monitoring networks for the purpose of optimizing field quality control sampling to give the highest quality monitoring data with minimal impact on resources. The DQO process, developed primarily to aid in cleanup and restoration activities, is a systematic approach to designing sampling, and analysis programs with improved efficiency, cost savings, and measureable an… more
Date: November 1, 1995
Creator: Garcia, L.M.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the polarized forward-backward asymmetry of B quarks using momentum-weighted track charge at SLD

Description: This thesis presents a direct measurement of the parity-violating parameter A{sub b} by analyzing the polarized forward-backward asymmetry of b quarks in e{sup +}e{sup {minus}} {yields} Z{sup 0} {yields} b{bar b}. Data were taken at the Stanford Linear Accelerator Center (SLAC), with the Stanford Large Detector (SLD), which records the products of e{sup +}e{sup {minus}} interactions at a center of mass energy {radical}s = 91.2 GeV/c{sup 2} at the SLAC Linear Collider (SLC). The SLC/SLD experime… more
Date: November 1, 1995
Creator: Junk, T.R.
Partner: UNT Libraries Government Documents Department
open access

Microstructural development of rapid solidification in Al-Si powder

Description: The microstructure and the gradient of microstructure that forms in rapidly solidificated powder were investigated for different sized particles. High pressure gas atomization solidification process has been used to produce a series of Al-Si alloys powders between 0.2 {mu}m to 150 {mu}m diameter at the eutectic composition (12.6 wt pct Si). This processing technique provides powders of different sizes which solidify under different conditions (i.e. interface velocity and interface undercooling)… more
Date: November 1, 1995
Creator: Jin, F.
Partner: UNT Libraries Government Documents Department
open access

A study of Ag/Ag(100) thin film growth with scanning tunneling microscopy

Description: Thin films are attracting more and more attention in both the industrial and scientific communities. Many applications of thin films have been developed in industry. By using various growth methods, thin films can be used in optics, microelectronic devices, magnetic recording media, and as protective coatings. In order to improve existing applications and to find new ones, it is essential to understand what makes them so useful in applications and what factors affect their properties. Therefore… more
Date: November 1, 1995
Creator: Wen, J.
Partner: UNT Libraries Government Documents Department
open access

Excited state proton transfer in 9-aminoacridine carboxamides in water and in DNA

Description: The 9-aminoacridine molecule is important in several different fields of chemistry. The absorption and fluorescence spectra of this compound are pH sensitive and it is this property that allowed it to be used as a pH probe in different chemical environments. The compound exhibits proton transfer reactions which are among the most fundamental of chemical reactions. The planarity of 9-aminoacridine allows it to intercalate into DNA. Intercalation is a process in which the aromatic flat surface of… more
Date: November 1, 1995
Creator: Smith, C. A.
Partner: UNT Libraries Government Documents Department
open access

Spectral hole burning studies of photosystem II

Description: Low temperature absorption and hole burning spectroscopies were applied to the D1-D2-cyt b{sub 559} and the CP47 and CP43 antenna protein complexes of Photosystem H from higher plants. Low temperature transient and persistent hole-burning data and theoretical calculations on the kinetics and temperature dependence of the P680 hole profile are presented and provide convincing support for the linker model. Implicit in the linker model is that the 684-nm-absorbing Chl a serve to shuttle energy fro… more
Date: November 1, 1995
Creator: Chang, H.C.
Partner: UNT Libraries Government Documents Department
open access

Effect of a fluorinated nickel surface on the decomposition of perfluorodiethoxymethane

Description: Perfluoropolyethers (PFPEs) are a commercial class of lubricants widely used in computer and aerospace industries. This is a study of the degradation of a perfluorinated ether in the presence of a metal fluoride. Perfluorodiethoxymethane (PFDEM) is a PFPE analog. Temperature programmed desorption shows no contribution of PFDEM toward nickel fluoride on an NiF{sub 2} surface obtained by CF{sub 3}I adsorption. Higher coverages of nickel fluoride do not show any evidence of NiF{sub 2} contribution… more
Date: November 9, 1995
Creator: Sreevidya, S.
Partner: UNT Libraries Government Documents Department
open access

Organic transformations catalyzed by methylrhenium trioxide

Description: Methylrhenium trioxide (MTO), CH{sub 3}ReO{sub 3}, was first prepared in 1979. MTO forms stable or unstable adducts with electron-rich ligands, such as amines (quinuclidine, 1,4-diazabicyclo-octane, pyridine, aniline, 2,2{prime}-bipyridine), alkynes, olefins, 1,2-diols, catechols, hydrogen peroxide, water, thiophenols, 1,2-dithiols, triphenylphosphine, 2-aminophenols, 2-aminothiophenols, 8-hydroxyquinoline and halides (Cl-, Br-, I-). After coordination, different further reactions will occur fo… more
Date: November 1, 1995
Creator: Zhu, Z.
Partner: UNT Libraries Government Documents Department
open access

On the implementation of error handling in dynamic interfaces to scientific codes

Description: With the advent of powerful workstations with windowing systems, the scientific community has become interested in user friendly interfaces as a means of promoting the distribution of scientific codes to colleagues. Distributing scientific codes to a wider audience can, however, be problematic because scientists, who are familiar with the problem being addressed but not aware of necessary operational details, are encouraged to use the codes. A more friendly environment that not only guides user… more
Date: November 1, 1993
Creator: Solomon, Cynthia Jean
Partner: UNT Libraries Government Documents Department
open access

Three dimensional simulations of space charge dominated heavy ion beams with applications to inertial fusion energy

Description: Heavy ion fusion requires injection, transport and acceleration of high current beams. Detailed simulation of such beams requires fully self-consistent space charge fields and three dimensions. WARP3D, developed for this purpose, is a particle-in-cell plasma simulation code optimized to work within the framework of an accelerator`s lattice of accelerating, focusing, and bending elements. The code has been used to study several test problems and for simulations and design of experiments. Two app… more
Date: November 1, 1994
Creator: Grote, D. P.
Partner: UNT Libraries Government Documents Department
open access

The structure and morphology of semiconductor nanocrystals

Description: Colloidal semiconductor nanocrystals were studied using High Resolution Transmission Electron Microscopy (HRTEM). Organically capped nanocrystals were found to have faceted shapes consistent with Wulff polyhedra after the effects of capping ligands on surface energies were taken into account. The basic shape thus derived for wurtzite (WZ) structure CdSe nanocrystals capped by tri-octyl phosphine oxide (TOPO) was a truncated hexagonal prism, elongated alone the <001> axis with (100) and (002) fa… more
Date: November 1, 1997
Creator: Kadavanich, A.V.
Partner: UNT Libraries Government Documents Department
open access

Improving the Design and Analysis of Superconducting Magnets for Particle Accelerators

Description: The field quality in superconducting magnets has been improved to a level that it does not appear to be a limiting factor on the performance of RHIC. The many methods developed, improved and adopted during the course of this work have contributed significantly to that performance. One can not only design and construct magnets with better field quality than in one made before but can also improve on that quality after construction. The relative field error ({Delta}B/B) can now be made as low as … more
Date: November 1, 1996
Creator: Gupta, R. C.
Partner: UNT Libraries Government Documents Department
open access

A Spatial Discretization Scheme for Solving the Transport Equation on Unstructured Grids of Polyhedra

Description: In this work, we develop a new spatial discretization scheme that may be used to numerically solve the neutron transport equation. This new discretization extends the family of corner balance spatial discretizations to include spatial grids of arbitrary polyhedra. This scheme enforces balance on subcell volumes called corners. It produces a lower triangular matrix for sweeping, is algebraically linear, is non-negative in a source-free absorber, and produces a robust and accurate solution in thi… more
Date: November 1, 2000
Creator: Thompson, Kelly Glen
Partner: UNT Libraries Government Documents Department
open access

An Analysis Framework Addressing the Scale and Legibility of Large Scientific Data Sets

Description: Much of the previous work in the large data visualization area has solely focused on handling the scale of the data. This task is clearly a great challenge and necessary, but it is not sufficient. Applying standard visualization techniques to large scale data sets often creates complicated pictures where meaningful trends are lost. A second challenge, then, is to also provide algorithms that simplify what an analyst must understand, using either visual or quantitative means. This challenge can … more
Date: November 20, 2006
Creator: Childs, H. R.
Partner: UNT Libraries Government Documents Department
open access

Laser-plasma interactions relevant to Inertial Confinement Fusion

Description: Research into laser-driven inertial confinement fusion is now entering a critical juncture with the construction of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). Many of the remaining unanswered questions concerning NIF involve interactions between lasers and plasmas. With the eventual goal of fusion power in mind, laser-plasma interactions relevant to laser fusion schemes is an important topic in need of further research. This work experimentally addres… more
Date: November 2, 1998
Creator: Wharton, Kenneth Bradford
Partner: UNT Libraries Government Documents Department
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