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Kinetic Studies of the Reactions Occurring Between Tungsten and Gases at Low Pressure and High Temperatures

Description: Oxygen, nitrogen, and nitric oxide gases were passed through a system consisting of a tungsten filament, an ion gauge, and a mass spectrometer. The ion gauge recorded total pressures and the spectrometer recorded partlal pressures of O/sub 2/, N/sub 2/, NO, CO, COa, and H/sub 2/O. From the way these pressures changed with filamert temperature, the rates of conversion of O/sub 2/ to volatile tungsten oxides and O, and of NO to volatile tungsten oxides N/sub 2/ , O/sub 2/, and O were computed. Th… more
Date: April 1, 1962
Creator: Anderson, H. U.
Partner: UNT Libraries Government Documents Department
open access

Mass-spectrometric determination of trace elements in aqueous media without preconcentration

Description: Feasibility of using a low pressure glow discharge as an ion source for the mass spectrometric determination of trace elements in aqueous media was investigated. A cryogenically cooled hollow cathode ion source was developed to analyze aqueous samples without external preconcentration. Aqueous solutions containing seventy elements were analyzed and the detection limits, sensitivity factors, and linear regression correlation coefficients were determined. A standard test solution of trace element… more
Date: October 1, 1981
Creator: Foss, G. O.
Partner: UNT Libraries Government Documents Department
open access

Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part II. Recovery of Ammonia from Sour Waters

Description: Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with… more
Date: March 1, 1990
Creator: Poole, L. J. & King, C. J.
Partner: UNT Libraries Government Documents Department
open access

Design of a rural water provision system to decrease arsenic exposure in Bangladesh

Description: Researchers at the Lawrence Berkeley National Laboratory have invented ARUBA (Arsenic Removal Using Bottom Ash) a material that effectively and affordably removes high concentrations of arsenic from contaminated groundwater. The technology is cost-effective because the substrate?bottom ash from coal fired power plants?is a waste material readily available in South Asia. During fieldwork in four sub-districts ofBangladesh, ARUBA reduced groundwater arsenic concentrations as high as 680 ppb to be… more
Date: January 7, 2009
Creator: Mathieu, Johanna
Partner: UNT Libraries Government Documents Department
open access

CARBON AND DEUTERIUM NUCLEAR MAGNETIC RESONANCE IN SOLIDS

Description: In Chapter I we present the results on a study of cross polarization dynamics, between protons and carbon-13 in adamantane, by the direct observation of the dilute, carbon-13, spins. These dynamics are an important consideration in the efficiency of proton enhancement double-resonance techniques and they also provide good experimental models for statistical theories of cross relaxation. In order to test these theories we present a comparison of the experimental and theoretical proton dipolar fl… more
Date: July 1, 1976
Creator: Shattuck, Thomas Wayne
Partner: UNT Libraries Government Documents Department
open access

Diffusion of trichloroethylene through the threaded joints of PVC (polyvinylchloride) pipe

Description: The data engineers and scientists use to determine if the groundwater supply is contaminated are derived from analysis of samples taken largely from monitoring wells. For these data to be reliable several factors must be considered. One factor is the integrity of the monitoring well. In this project, emphasis has been placed on the potential impact on water quality caused by diffusion across the threaded joints of PVC pipe. In this study, the diffusion of trichloroethylene across several common… more
Date: December 1, 1990
Creator: Jerome, Karen M.
Partner: UNT Libraries Government Documents Department
open access

Vibrational spectroscopy of water interfaces

Description: The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer … more
Date: December 1, 1994
Creator: Du, Q.
Partner: UNT Libraries Government Documents Department
open access

Characterization of electrochemically modified polycrystalline platinum surfaces

Description: The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a singl… more
Date: December 1, 1991
Creator: Krebs, L. C. & Ishida, Takanobu
Partner: UNT Libraries Government Documents Department
open access

Experimental and Numerical Investigation of the Role of Initial Condition of the Dynamics of Rayleigh-Taylor Mixing

Description: Experiments and direct numerical simulations have been performed to examine the effects of initial conditions on the dynamics of a Rayleigh-Taylor mixing layer. Experiments were performed on a water channel facility to quantify the interfacial and velocity perturbations initially present at the two-fluid interface in a small Atwood number mixing layer. The measurements have been parameterized for implementation in numerical simulations of the experiment, and two- and three-dimensional direct nu… more
Date: August 16, 2004
Creator: Mueschke, N
Partner: UNT Libraries Government Documents Department
open access

Microfabrication of an Implantable silicone Microelectrode array for an epiretinal prosthesis

Description: Millions of people suffering from diseases such as retinitis pigmentosa and macular degeneration are legally blind due to the loss of photoreceptor function. Fortunately a large percentage of the neural cells connected to the photoreceptors remain viable, and electrical stimulation of these cells has been shown to result in visual perception. These findings have generated worldwide efforts to develop a retinal prosthesis device, with the hope of restoring vision. Advances in microfabrication, i… more
Date: June 10, 2003
Creator: Maghribi, M
Partner: UNT Libraries Government Documents Department
open access

Space-Charge Electrostatic Precipitation

Description: An improved electrostatic precipitator called a space charge precipitator was tested and studied. A space charge precipitator differs from a conventional model in that the fields necessary to move the particles from the gas to the collecting surfaces are provided by a cloud of charged innocuous drops, such as glycerine or water, rather than by a charged electrode system. The flow conditions, electrical equipment, and physical dimensions of the test precipitator are typical of industrial applica… more
Date: May 1, 1977
Creator: Middleton, Charles Eugene
Partner: UNT Libraries Government Documents Department
open access

Water-enhanced solubility of carboxylic acids in organic solvents and its applications to extraction processes

Description: The solubilities of carboxylic acids in certain organic solvents increase remarkably with an increasing amount of water in the organic phase. This phenomenon leads to a novel extract regeneration process in which the co-extracted water is selectively removed from an extract, and the carboxylic acid precipitates. This approach is potentially advantageous compared to other regeneration processes because it removes a minor component of the extract in order to achieve a large recovery of acid from … more
Date: November 1, 1991
Creator: Starr, J. N. & King, C. J.
Partner: UNT Libraries Government Documents Department
open access

Vibration-rotation-tunneling dynamics in small water clusters

Description: The goal of this work is to characterize the intermolecular vibrations of small water clusters. Using tunable far infrared laser absorption spectroscopy, large amplitude vibration-rotation-tunneling (VRT) dynamics in vibrationally excited states of the water dimer and the water trimer are investigated. This study begins with the measurement of 12 VRT subbands, consisting of approximately 230 transitions, which are assigned to an 82.6 cm{sup {minus}1} intermolecular vibration of the water dimer-… more
Date: November 1, 1992
Creator: Pugliano, N.
Partner: UNT Libraries Government Documents Department
open access

Supply Curves of Conserved Energy

Description: Supply curves of conserved energy provide an accounting framework that expresses the potential for energy conservation. The economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost of conserved energy is less than the price of the energy it replaces. A supply curve of conserved energy is independent of energy prices; however, the economical reserves of conserved energy will depend on energy prices. … more
Date: May 1, 1982
Creator: Meier, Alan Kevin
Partner: UNT Libraries Government Documents Department
open access

Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

Description: The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content … more
Date: August 5, 2009
Creator: Lawler, Katherine
Partner: UNT Libraries Government Documents Department
open access

An Orifice Plate Pulse Column for Liquid-Liquid Extraction

Description: A study was made of the performance of an orifice plate pulse column which is essentially a spray column containing internal constrictions in the form of orifices. The chemical system studied was acetic acid-waterhexone, and the variables considered were pulse frequency, throughput, phase continuity, and direction of solute transfer. For comparison purposes, several runs were made with a conventional spray column. Curves are presented showing the effect of the column variables on the column eff… more
Date: August 23, 1954
Creator: O'Brien, D. C.
Partner: UNT Libraries Government Documents Department
open access

The Kinetics of the Complexing of Ferric Ion by Thiocyanate and Chloride Ions

Description: An apparatus for rapidly mixing two solutions and recording the light absorption, which was developed by Connick and Below, has been modified. The mixing characteristics were studied and models were developed in an attempt to umder stand the observed mixing phenomena. The apparatus was applied to a study of the kinetics of the reactions Fe/sup +++/ + SCN/sup -/ = FeSCN/sup ++/ and Fe/ sup +++/ Cl/sup -/ = FeCl/sup ++/ in aqueous solution, with both reactions having the forward rate law STAd(FeX… more
Date: December 1, 1957
Creator: Coppel, Claude Peter
Partner: UNT Libraries Government Documents Department
open access

Probing Properties of Glassy Water and Other Liquids with Site Selective Spectroscopies

Description: The standard non-photochemical hole burning (NPHB) mechanism, which involves phonon-assisted tunneling in the electronically excited state, was originally proposed to explain the light-induced frequency change of chemically stable molecules in glassy solids at liquid helium temperatures by this research group more than two decades ago. The NPHB mechanism was then further elucidated and the concept of intrinsic to glass configurational relaxation processes as pre-mediating step to the hole burni… more
Date: August 12, 2005
Creator: Dang, Nhan Chuong
Partner: UNT Libraries Government Documents Department
open access

Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

Description: The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to… more
Date: August 27, 2002
Creator: Anderson, Brian Curtis
Partner: UNT Libraries Government Documents Department
open access

An Experimental Investigation of Two-Phase, Two-Component Flow in a Horizontal, Converging-Diverging Nozzle

Description: A discussion is presented of an investigation of the flow characteristics in a horizontal, converging-diverging nozzle for a two-phase, air- water system. The primary consideration, to determine the effects of accelerating the liquid phase by the gaseous phase, was measured in terms of nozzle exit water velocity, exit slip ratio, and exit acceleration factor. A gamma-ray-attenuation technique was used to determine these values by determining the average cross-sectional void fraction, the ratio … more
Date: July 1, 1963
Creator: Vogrin, J. A., Jr.
Partner: UNT Libraries Government Documents Department
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High Density Slag Concrete

Description: Test results are presented that show that a strong concrete weighing approximately 185 lb/ft/sup 3/ can be made using water, waste lead slag, and Ciment Fondu. Feasibility, materials, mortar tests, concrete tests, and Ciment Fondu concretes are discussed. A 24-in.-thick concrete shield wall would have to be increased in thickness by 5 in. if slag concrete is used in place of barytes or magnetite concrete. On a pound-for-pound basis, the waste lead slag concrete materials were 30% cheaper than b… more
Date: August 1, 1963
Creator: Northup, T.E.
Partner: UNT Libraries Government Documents Department
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