19,330 Matching Results

Search Results

Results: 1 - 24 next
open access

Development of a Drillrod/Telemetry Radar

Description: Efficient extraction of deeply buried natural resources is dependent upon accurate geologic models. The model becomes the basis for developing plans for extraction of the resource. Geoscientists working in geothermal and hydrocarbon recovery have a great deal in common with fellow geoscientists working in the mining industry. They appreciate the intractable problem of increasing the depth of investigation to tens of meters from the wellbore. The goal of this project was to develop a borehole ra… more
Date: November 12, 1999
Creator: Raton Technology Research, Inc.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Kelastic variable wall mining machine. Interim final report

Description: This machine cuts coal along a longwall face extending up to 500 feet by a rotating auger with bits. The machine also transports the coal that is cut acting as screw conveyor. By virtue of an integral shroud comprising part of the conveyor the machine is also amenable to a separation of the zones where men work from air being contaminated by dust and methane gas by the cutting action. Beginning as single intake air courses, the air separates at the working section where one split provides fresh… more
Date: November 12, 1995
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quarterly Progress Report

Description: The Federal Energy Technology Center (FETC) at Pittsburgh contracted with the MJTRE Corporation to perform Research Guidance Studies that will assist the Center and other relevant offices in the Department of Energy in evaluating and prioritizing research in the areas of coal and natural gas conversion. MITRE was reorganized in December 1995, which resulted in the formation of Mitretek Systems Inc. Mitretek has been performing this work on MITRE's behalf awaiting completion of contract novation… more
Date: November 12, 1998
Creator: Gray, David & Tomlinson, Glen
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An evaluation of the management system verification pilot at Hanford

Description: The Chemical Management System (CMS), currently under development at Hanford, was used as the ''test program'' for pilot testing the value added aspects of the Chemical Manufacturers Association's (CMA) Management Systems Verification (MSV) process. The MSV process, which was developed by CMA's member chemical companies specifically as a tool to assist in the continuous improvement of environment, safety and health (ESH) performance, represents a commercial sector ''best practice'' for evaluati… more
Date: November 12, 1998
Creator: Briggs, C. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Power Systems Development Facility progress report

Description: This is a report on the progress in design and construction of the Power Systems Development Facility. The topics of the report include background information, descriptions of the advanced gasifier, advanced PFBC, particulate control devices, and fuel cell. The major activities during the past year have been the final stages of design, procurement of major equipment and bulk items, construction of the facility, and the preparation for the operation of the Facility in late 1995.
Date: November 1995
Creator: Rush, R. E.; Hendrix, H. L.; Moore, D. L.; Pinkston, T. E.; Vimalchand, P. & Wheeldon, J. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Power Systems Development Facility -- Current status

Description: Southern Company Services, Inc. (SCS) has entered into a cooperative agreement with the US Department of Energy (DOE) to build and operate the Power Systems Development Facility (PSDF), currently under construction in Wilsonville, Alabama, 40 miles southeast of Birmingham. The objectives of the PSDF are to develop advanced coal-fired power generation technologies through testing and evaluation of hot gas cleanup systems and other major components at the pilot scale. The performance of component… more
Date: November 1995
Creator: Pinkston, T. E.; Maxwell, J. D.; Leonard, R. F. & Vimalchand, P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Tungsten Z-Pinch Long Implosions on the Saturn Generator

Description: Recent success on the Saturn and Z accelerators at Sandia National Laboratories have demonstrated the ability to scale z-pinch parameters to increasingly larger current pulsed power facilities. Next generation machines will require even larger currents (>20 MA), placing further demands on pulsed power technology. To this end, experiments have been carried out on Saturn operating in a long pulse mode, investigating the potential of lower voltages and longer implosion times while still maintai… more
Date: November 5, 1999
Creator: Douglas, Melissa R.; Deeney, Christopher; Spielman, Rick B.; Coverdale, Christine A.; Roderick, N. F. & Haines, M. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Uncertainty Propagation in Calibration of Parallel Kinematic Machines

Description: Over the last decade, multi-axis machine tools and robots based on parallel kinematic mechanisms (PKMs) have been developed and marketed worldwide. Positional accuracy in these machines is controlled by accurate knowledge of the kinematic parameters which consists of the joint center locations and distances between joint pairs. Since these machines tend to be rather large in size, the kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these … more
Date: November 2, 1999
Creator: JOKIEL JR.,BERNHARD & ZIERGERT,JOHN C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Using Cytochrome c{sub 3} to Make Selenium Nanowires

Description: We report on a new method to make nanostructures, in this case selenium nanowires, in aqueous solution at room temperature. We used the protein cytochrome c{sub 3} to reduce selenate (SeO{sub 4}{sup 2{minus}}) to selenium (Se{sup 0}). Cytochrome c{sub 3} is known for its ability to catalyze reduction of metals including U{sup VI} {yields} U{sup IV}, Cr{sup VI} {yields} Cr{sup III}, Mo{sup VI} {yields} Mo{sup IV}, Cu{sup II} {yields} Cu{sup 0}, Pb{sup II} {yields} Pb{sup 0}, Hg{sup II} {yields} … more
Date: November 24, 1999
Creator: Abdelouas, A.; Franco, R.; Gong, W. L.; Lutze, W.; Moura, I. & Shelnutt, John A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Tailored Porous Materials

Description: Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, po… more
Date: November 9, 1999
Creator: Barton, Thomas J.; Bull, Lucy M.; Klemperer, Walter G.; Loy, Douglas A.; McEnaney, Brian; Misono, Makoto et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Foam Micromechanics

Description: Foam evokes many different images: waves breaking at the seashore, the head on a pint of Guinness, an elegant dessert, shaving, the comfortable cushion on which you may be seated... From the mundane to the high tech, foams, emulsions, and cellular solids encompass a broad range of materials and applications. Soap suds, mayonnaise, and foamed polymers provide practical motivation and only hint at the variety of materials at issue. Typical of mukiphase materiaIs, the rheoIogy or mechanical behavi… more
Date: November 3, 1998
Creator: Kraynik, A.M.; Neilsen, M.K.; Reinelt, D.A. & Warren, W.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Antireflection Coating Design for Series Interconnected Multi-Junction Solar Cells

Description: AR coating design for multi-junction solar cells can be more challenging than in the single junction case. Reasons for this are discussed. Analytical expressions used to optimize AR coatings for single junction solar cells are extended for use in monolithic, series interconnected multi-junction solar cell AR coating design. The result is an analytical expression which relates the solar cell performance (through J{sub SC}) directly to the AR coating design through the device reflectance. It is a… more
Date: November 29, 1999
Creator: Aiken, Daniel J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

Description: {sup 13}C-enriched polyethylene was subjected to {gamma}-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by {sup 13}C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studie… more
Date: November 19, 1999
Creator: Assink, Roger A.; Celina, Mathias C.; Dunbar, Timothy D.; Alam, Todd M.; Clough, Roger Lee & Gillen, Kenneth T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Applications of capillary electrophoresis and laser-induced fluorescence detection to the analysis of trace species: From single cells to single molecules

Description: This Ph.D. Thesis describes several separation and detection schemes for the analysis of small volume and amount of samples, such as intracellular components and single enzymes developed during research. Indirect Laser-induced fluorescence detection and capillary electrophoresis were used to quantify lactate and pyruvate in single red blood cells. The assay of specific enzyme activities was achieved by monitoring the highly fluorescent enzymatic reaction product, NADH. LDH activity was found no… more
Date: November 1, 1995
Creator: Qifeng, X.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Anisotropic superconducting and normal state magnetic properties of single crystals of RNi*2*B*2*C compounds (R = Y, Gd, Dy, Ho, Er, and Tm)

Description: The interaction of superconductivity with magnetism has been one of the most interesting and important phenomena in solid state physics since the 1950`s when small amounts of magnetic impurities were incorporated in superconductors. The discovery of the magnetic superconductors RNi{sub 2}B{sub 2}C (R = rare earth, Y) offers a new system to study this interaction. The wide ranges of superconducting transition (T{sub c}) and antiferromagnetic (AF) ordering temperatures (T{sub N}) (0 K {le} T{sub … more
Date: November 1, 1995
Creator: Cho, B.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
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
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Dynamical studies of periodic and disordered systems

Description: The time evolution of two classes of systems is studied with real time molecular dynamics simulations. The first consists of a coupled electron-lattice system. For a periodic system, we present results for the time evolution of a one-dimensional system consisting of an electron, described by a tight-binding Hamiltonian, and a harmonic lattice, coupled by a deformation-type potential. We solve numerically the nonlinear system of equations of motion for this model in order to study the effects of… more
Date: November 1, 1995
Creator: Kopidakis, G.
Item Type: Refine your search to only Thesis or Dissertation
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.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
Back to Top of Screen