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Consumption of Slab Zinc in the United States by Industries, Grades, and Geographic Divisions, 1940-45: Including a Summary of Consumption Since 1900

Description: Report issued by the U.S. Bureau of Mines discussing the U.S. slab-zinc consumption between the years of 1940-1945. As stated in the introduction, "this information circular summarized basic data collected for many years by the Bureau of Mines, but in particular presents for the 1940-45 period details derived from the comprehensive slab zinc consumption survey inaugurated in 1940" (p. 3). The different uses for slab zinc are presented. This report includes maps, tables, and illustrations.
Date: February 1948
Creator: Ransome, Alfred L.
Partner: UNT Libraries Government Documents Department

Zinc and Its Alloys

Description: Report issued by the Bureau of Standards discussing world production of zinc and zinc alloys. History, metallurgy, and structural properties of zinc are presented. This report includes tables, illustrations, and photographs.
Date: November 6, 1931
Creator: United States. Bureau of Standards.
Partner: UNT Libraries Government Documents Department

Recovery of Zinc from Low-Grade and Complex Ores

Description: From Introduction: "Vocalization in retorts has been, until recently, the only commercial process of producing spelter, hence the zinc mine operators have had to meet the terms of the zinc mine operators have had to meet the terms of the zinc smelters in regard to the following requirements: (1) Minimum percentage of zinc the ore must contain; (2) the chemical combination of the zinc in the ore; (3) the proportion present of those elements that interfere with the successful recovery of the zinc when the ore is retorted. As stated previously, and as will be shown later, a large part of the valuable mineral content of the ore is lost in effecting this concentration. As a result of the other requirements that have to be met in zinc smelting, much zinc is lost in the mining and milling of zinc ore."
Date: 1919
Creator: Lyon, Dorsey A. & Ralston, Oliver C.
Partner: UNT Libraries Government Documents Department

Magnetomorphic Oscillations in Zinc

Description: In making this study it is important to search for ways to enhance and, if possible, make detection of MMO signals simpler in order that this technique for obtaining FS measurements may be extended to other materials. This attempt to improve measurement techniques has resulted in a significant discovery: the eddy-current techniques described in detail in a later section which should allow MMO to be observed and sensitively measured in many additional solids. The second major thrust of the study has been to use the newly discovered eddy-current technique in obtaining the first indisputable observation of MMO in zinc.
Date: August 1970
Creator: Waller, William Marvin
Partner: UNT Libraries

The Electrothermic Metallurgy of Zinc

Description: Report issued by the Bureau of Mines over the electrothermic metallurgy and smelting of zinc. Different smelting methods, processes, and equipment are presented and discussed. This report includes tables, illustrations, and photographs.
Date: May 1923
Creator: O'Harra, B. Marvel
Partner: UNT Libraries Government Documents Department

Oxidized Zinc Deposits of the United States: Part 1. General Geology

Description: From introduction: This report is intended as a descriptive summary. The fieldwork on which it is based was completed in the central Western States in 1952-56, and additional studies were made in the Central and Eastern States before and after the western studies. Research and compilation were completed in 1956-59. Other reports will describe in detail the geology and origin of the oxidized zinc deposits in Colorado, Utah, Nevada, and California. (See also Heyl and Bozion, 1960.)
Date: 1962
Creator: Heyl, Allen V. & Bozion, C. N.
Partner: UNT Libraries Government Documents Department

Oxidized Zinc Deposits of the United States: Part 2. Utah

Description: From introduction: This report is compiled from fieldwork and available published data on the oxidized zinc deposits of Utah. Most of the deposits were examined by the author during the autumns of 1952-55 as part of a general study of oxidized zinc deposits of the Western States. In addition, several deposits were visited by geologists of the U.S. Geological Survey as a part of mineral investigation studies since 1940. In the process of obtaining this information many mining companies and individuals have been consulted.
Date: 1963
Creator: Heyl, Allen V.
Partner: UNT Libraries Government Documents Department

Oxidized Zinc Deposits of the United States: Part 3. Colorado

Description: From abstract: Deposits of oxidized zinc ore are widely distributed in the western part of Colorado in the Rocky Mountains west of the Front Range and in the uplifted plateaus that border the main area of the Colorado Plateau. The principal production and reserves are restricted to several mining districts--Leadville. Aspen, Monarch, Spring Creek. Horseshoe, Tomichi, Tincup, and Rico--in all of which limestone and dolomites of Paleozoic age are the main host rocks. One deposit, that of the Sedalia mine near Salida has produced commercial quantities of oxidized zinc-copper ore from noncarbonate host rocks, but other known deposits in noncarbonate rocks are mostly low grade.
Date: 1964
Creator: Heyl, Allen V.
Partner: UNT Libraries Government Documents Department

Defect Behaviors in Zinc Oxide and Zinc Titanates Ceramics from First Principles Computer Simulations

Description: ZnO and ZnO-TiO2 ceramics have intriguing electronic and mechanical properties and find applications in many fields. Many of these properties and applications rely on the understanding of defects and defect processes in these oxides as these defects control the electronic, catalytic and mechanical behaviors. The goal of this dissertation is to systematically study the defects and defects behaviors in Wurtzite ZnO and Ilmenite ZnTiO3 by using first principles calculations and classical simulations employing empirical potentials. Firstly, the behavior of intrinsic and extrinsic point defects in ZnO and ZnTiO3 ceramics were investigated. Secondly, the effect of different surface absorbents and surface defects on the workfunction of ZnO were studied using DFT calculations. The results show that increasing the surface coverage of hydrocarbons decreased the workfunction. Lastly, the stacking fault behaviors on ilmenite ZnTiO3 were investigated by calculating the Generalized Stacking Fault (GSF) energies using density functional theory based first principles calculations and classical calculations employing effective partial charge inter-atomic potentials. The gamma-surfaces of two low energy surfaces, (110) and (104), of ZnTiO3 were fully mapped and, together with other analysis such as ideal shear stress calculations.
Date: December 2016
Creator: Sun, Wei
Partner: UNT Libraries

Predicting the Site-Specific Bioavailability of Zinc Using the Indicator Species Procedure: A Case Study

Description: National Water Quality Criteria intended to protect aquatic life and their uses from the adverse effects of pollutants may not be appropriate due to site-specific factors that alter chemical bioavailability. The Indicator Species Procedure may be used to derive site-specific criteria in order to account for differences in site-specific bioavailability. This procedure was implemented using zinc for three chemically different site (river) waters. The purpose of this study was to quantify the bioavailability of zinc in each site water and correlate results to water quality parameters and/or zinc speciation. Results demonstrated that national criteria for zinc accurately predicted the experimentally derived site-specific values within a factor of two when adjusted for water hardness. Particulate forms of zinc were shown to be biologically unavailable under conditions tested.
Date: May 1987
Creator: Parkerton, Thomas F.
Partner: UNT Libraries

Development of High Gain Ultraviolet Photo Detectors Based on Zinc Oxide Nanowires

Description: Semiconductor nanowires acts as an emerging class of materials with great potential for applications in future electronic devices. Small size, large surface to volume ratio and high carrier mobility of nanowires make them potentially useful for electronic applications with high integration density. In this thesis, the focus was on the growth of high quality ZnO nanowires, fabrication of field effect transistors and UV- photodetectros based on them. Intrinsic nanowire parameters such as carrier concentration, field effect mobility and resistivity were measured by configuring nanowires as field effect transistors. The main contribution of this thesis is the development of a high gain UV photodetector. A single ZnO nanowire functioning as a UV photodetector showed promising results with an extremely high spectral responsivity of 120 kA/W at wavelength of 370 nm. This corresponds to high photoconductive gain of 2150. To the best of our knowledge, this is the highest responsivity and gain reported so far, the previous values being responsivity=40 kA/W and gain=450. The enhanced photoconductive behavior is attributed to the presence of surface states that acts as hole traps which increase the life time of photogenerated electrons raising the photocurrent. This work provides the evidence of such solid states and preliminary results to modify the surface of ZnO nanowire is also produced.
Date: May 2014
Creator: Mallampati, Bhargav
Partner: UNT Libraries

Electrical and Structure Properties of High-κ Barium Tantalite and Aluminum Oxide Interface with Zinc Oxide for Applications in Transparent Thin Film Transistors

Description: ZnO has generated interest for flexible electronics/optoelectronic applications including transparent thin film transistors (TFTs). For this application, low temperature processes that simultaneously yield good electrical conductivity and optical transparency and that are compatible with flexible substrates such as plastic, are of paramount significance. Further, gate oxides are a critical component of TFTs, and must exhibit low leakage currents and self-healing breakdown in order to ensure optimal TFTs switching performance and reliability. Thus, the objective of this work was twofold: (1) develop an understanding of the processing-structure-property relationships of ZnO and high-κ BaTa2O6 and Al2O3 (2) understand the electronic defect structure of BaTa2O6 /ZnO and Al2O3/ZnO interfaces and develop insight to how such interfaces may impact the switching characteristics (speed and switching power) of TFTs featuring these materials. Of the ZnO films grown by atomic layer deposition (ALD), pulsed laser deposition (PLD) and magnetron sputtering at 100-200 °C, the latter method exhibited the best combination of n-type electrical conductivity and optical transparency. These determinations were made using a combination of photoluminescence, photoluminescence excitation, absorption edge and Hall measurements. Metal-insulator-semiconductor devices were then fabricated with sputtered ZnO and high-κ BaTa2O6 and Al2O3 and the interfaces of high-κ BaTa2O6 and Al2O3 with ZnO were analyzed using frequency dependent C-V and G-V measurements. The insulator films were deposited at room temperature by magnetron sputtering using optimized processing conditions. Although the Al2O3 films exhibited a lower breakdown strength and catastrophic breakdown behavior compared to BaTa2O6/ZnO interface, the Al2O3/ZnO interface was characterized by more than an order of magnitude smaller density of interface traps and interface trapped charge. The BaTa2O6 films in addition were characterized by a significantly higher concentration of fixed oxide charge. The transition from accumulation to inversion in the Al2O3 MIS structure was considerably sharper, and occurred at less than one tenth of ...
Date: August 2011
Creator: Kuo, Fang-Ling
Partner: UNT Libraries

The Role of Crystallographic Texture in Achieving Low Friction Zinc Oxide Nanolaminate Films

Description: Metal oxide nanolaminate films are potential high temperature solid lubricants due to their ability to exhibit significant plasticity when grain size is reduced to the nanometer scale, and defective growth structure is achieved by condensation of oxygen vacancies to form intrinsic stacking faults. This is in contrast to conventional microcrystalline and single crystal oxides that exhibit brittle fracture during loading in a sliding contact. This study emphasizes the additional effect of growth orientation, in particular crystallographic texture, on determining the sliding friction behavior in nanocolumnar grain zinc oxide films grown by atomic layer deposition. It was determined that zinc oxide low (0002) versus higher (101 ̅3) surface energy crystallographic planes influenced the sliding friction coefficient. Texturing of the (0002) grains resulted in a decreased adhesive component of friction thereby lowering the sliding friction coefficient to ~0.25, while the friction coefficient doubled to ~0.5 with increasing contribution of surface (101 ̅3) grains. In addition, the variation of the x-ray grazing incident angle from 0.5° to 5° was studied to better understand the surface grain orientation as a function of ZnO layer thickness in one versus four bilayer nanolaminates where the under layer (seed layer) was load-bearing Zn(Ti,Zr)O3.
Date: December 2015
Creator: Mojekwu, Nneoma
Partner: UNT Libraries

"High Quantum Efficiency of Band-Edge Emission from ZnO Nanowires"

Description: External quantum efficiency (EQE) of photoluminescence as high as 20 percent from isolated ZnO nanowires were measured at room temperature. The EQE was found to be highly dependent on photoexcitation density, which underscores the importance of uniform optical excitation during the EQE measurement. An integrating sphere coupled to a microscopic imaging system was used in this work, which enabled the EQE measurement on isolated ZnO nanowires. The EQE values obtained here are significantly higher than those reported for ZnO materials in forms of bulk, thin films or powders. Additional insight on the radiative extraction factor of one-dimensional nanostructures was gained by measuring the internal quantum efficiency of individual nanowires. Such quantitative EQE measurements provide a sensitive, noninvasive method to characterize the optical properties of low-dimensional nanostructures and allow tuning of synthesis parameters for optimization of nanoscale materials.
Date: December 1, 2010
Creator: Gargas, Daniel; Gao, Hanwei; Wang, Hungta & Peidong, Yang
Partner: UNT Libraries Government Documents Department