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Description: We present a class of compact, monolithic, photonic sensors consisting of multiple section edge emitting lasers with functionalized lateral surface coatings for low level detection of chemical or biological agents. Specifically, we discuss 8 {micro}m x 250 {micro}m Pd-coated H{sub 2} sensors and configurations to reduce the minimum detection limit from 138ppm for passive sensors to 1ppm for active sensors. Compared with conventional optical H{sub 2} sensors that use fiber gratings, surface plasmon resonances, or surface reflectance, our sensors offer the advantages of smaller size, wider dynamic range, monolithic integration of laser source and detector, and 2-D scalability to arrays of sensors that are functionalized to detect different agents.
Date: July 5, 2007
Creator: Goddard, L L; Bond, T C; Cole, G D & Behymer, E M
Partner: UNT Libraries Government Documents Department

Surface roughness effects on the solar reflectance of cool asphalt shingles

Description: We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with small corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.
Date: February 17, 2008
Creator: Akbari, Hashem; Berdahl, Paul; Akbari, Hashem; Jacobs, Jeffry & Klink, Frank
Partner: UNT Libraries Government Documents Department

Development of Lithium Deposition Techniques for TFTR

Description: The ability to increase the quantity of lithium deposition into TFTR beyond that of the Pellet Injector while minimizing perturbations to the plasma provides interesting experimental and operational options. Two additional lithium deposition tools were developed for possible application during the 1996 Experimental Schedule: a solid lithium target probe for real-time deposition, and a lithium effusion oven for deposition between discharges. The lithium effusion oven was operated in TFTR to deposit lithium on the Inner Limiter in the absence of plasma. This resulted in the third highest power TFTR discharge.
Date: October 1, 1997
Creator: Gorman, J.; Johnson, D.; Kugel, H.W.; Labik, G.; Lemunyan, G. & al, et
Partner: UNT Libraries Government Documents Department

Dissolution rates and surface chemistry of feldspar glass and crystal. Final technical report, June 15, 1995 - August 14, 2001

Description: Final report summarizing the completed work of the project entitled 'Dissolution of Feldspar in the Field and Laboratory.' One of the highly debated questions today in low-temperature geochemical kinetics centers upon the rate and mechanism of dissolution of feldspar, the most common mineral in the crust. In this project, the mechanisms of feldspar dissolution were investigated by emphasizing experiments with feldspar glass and crystal while comparing surface and solution chemistry. Specifically, laboratory work focused on the structure of altered surface layers on feldspars, the rate of dissolution of feldspar crystal and glass, and the presence of porosity and surface coatings on feldspars. In a complementary field project, the use of Sr concentrations and isotopic ratios were used to calculate feldspar dissolution rates.
Date: June 11, 2002
Creator: Brantley, S. & Pantano, C.
Partner: UNT Libraries Government Documents Department

Department of Energy`s Wire Development Workshop - Superconductivity program for electric systems

Description: The 1996 High-Temperature Superconducting Wire Development Workshop was held on January 31--February 1 at the Crown Plaza Tampa Westshore in Tampa, Florida. The meeting was hosted by Tampa Electric Company and sponsored by the Department of Energy`s Superconductivity Program for Electric Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. Tampa Electric`s Greg Ramon began the meeting by giving a perspective on the changes now occurring in the utility sector. Major program wire development accomplishments during the past year were then highlighted, particularly the world record achievements at Los Alamos and Oak Ridge National Laboratories. The meeting then focussed on three priority technical issues: thallium conductors; AC losses in HTS conductors; and coated conductors on textured substrates. Following in-depth presentations, working groups were formed in each technology area to discuss and critique the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.
Date: June 1, 1996
Partner: UNT Libraries Government Documents Department

Replacement of thermally produced calcined clay with chemically structured pigments and methods for the same, Final technical report, Quarterly report, February 3, 1996-May 1, 1996

Description: The testing of control formulas was repeated due to instability of the TiO2 dispersion being used. Calcined clay controls were compared to the performance of layered pigments of the instant invention in coatings on brown natural kraft paperboard from Mead Corporation.
Date: December 31, 1996
Creator: Whalen-Shaw, M.
Partner: UNT Libraries Government Documents Department

Method for removing a stripe from the coating of a Fabry-Perot mirror

Description: We describe a method for removing a stripe from the coating of a Fabry-Perot mirror. This is accomplished by scraping off the soft coating with a finely lapped steel blade mounted on a precision mechanism to accurately position the blade and guide it for straight cuts. The width of the stripe is determined by selecting a blade of desired size. Previous methods and attempts are discussed.
Date: October 1, 1997
Creator: Perry, S.J. & Steinmetz, L.L.
Partner: UNT Libraries Government Documents Department

Manufacturing and coating by kinetic energy metallization

Description: The purpose of this effort was to theoretically model the underlying metal-coating phenomena when metal particles impact a metal surface at high velocities under room temperature conditions. The physical processes involved in the novel metal-coating process called Kinetic Energy Metallization (KEM) have been theoretically and numerically analyzed. A bonding model between the incident and the target metals has been proposed and preliminary numerical results agree reasonably well with the laboratory-obtained metal samples and suggest promise of validity for the present model. However, to put the proposed bonding model on a firmer basis further numerical effort is needed to be carried for various metals and operating conditions.
Date: February 9, 1998
Creator: Kang, S.W.
Partner: UNT Libraries Government Documents Department

TiN coating of the PEP-II low-energy ring aluminum arc vacuum chambers

Description: The PEP-II Low-Energy Ring will operate at a nominal energy of 3.1 GeV with a positron beam current of 2.1 A. Design parameters for vacuum components are 3.5 GeV at 3 A. The arc vacuum system is based on an aluminum antechamber concept. It consists of 192 pairs of 2 m long magnet chambers and 5.5 m long pumping chambers. Titanium nitride coating of the entire positron duct is needed in order to suppress beam instabilities caused by multipactoring and the {open_quotes}electron-cloud{close_quotes} effect. An extensive R&D program has been conducted to develop coating parameters that give proper stoichiometry and a suitable thickness of TiN. The total secondary emission yield of TiN-coated aluminum coupons has been measured after the samples were exposed to air and again after electron-beam bombardment. A coating facility has been built to cope with the large quantity of production chambers and the very tight schedule requirements.
Date: May 1, 1997
Creator: Kennedy, K.; Harteneck, B. & Millos, G.
Partner: UNT Libraries Government Documents Department

High temperature alkali corrosion of dense SiC and Si{sub 3}N{sub 4} coated with CMZP and Mg-Doped Al{sub 2}TiO{sub 5} in Coal Gas: Quarterly progress No. 9, July 1, 1996-September 30, 1996

Description: The second phase, coating of Si{sub 3}N{sub 4} by oxides, was started during this reporting period. Si{sub 3}N{sub 4} samples were coated by CMZP and Mg-coated Al{sub 2}TiO{sub 5} by a double-dip procedure.
Date: October 15, 1996
Creator: Brown, J.J.
Partner: UNT Libraries Government Documents Department

Effect of oxygen surfactant on the magnetic and structural properties of Co films grown on Cu(110)

Description: It was found that atomically flat Co(110) film could be grown on Cu(110) using O as a surfactant. To obtain detailed knowledge on the effect of O on the growth, as well as on the magnetic properties of Co overlayer, we carried out an investigation on this system using Auger Electron Spectroscopy (AES), Low Energy Electron Diffraction (LEED), Surface Magneto-Optic Kerr Effect (SMOKE), and Scanning Tunneling Microscopy (STM). With O as a surfactant, the initial growth of Co (< 1 ML) results in a flat monolayer structure. When the Co is thicker than 1 ML, three-dimensional clusters begin to form. These clusters become ordered islands at 3 ML Co and coalesce at about 5 ML Co. Above 5 ML Co, layer-by-layer growth resumes. No Cu segregation is observed. SMOKE studies at room temperature show that the Co film is magnetic above about 5 ML Co, with the magnetization easy axis along the [001] direction. On the other hand, without using oxygen as a surfactant, Co grows three-dimensionally on Cu(110). The Co overlayer has its easy magnetization axis along the [001] direction, but the onset of the magnetization was observed at 11 ML Co at room temperature.
Date: April 13, 2000
Creator: Ling, W.L.; Qiu, Z.Q.; Takeuchi, O.; Ogletree, D.F. & Salmeron, M.
Partner: UNT Libraries Government Documents Department

Pack cementation diffusion coatings for Fe-base and refractory alloys. Final report

Description: With the aid of computer-assisted calculations of the equilibrium vapor pressures in halide-activated cementation packs, processing conditions have been identified and experimentally verified for the codeposition of two or more alloying elements in a diffusion coating on a variety of steels and refractory metal alloys. A new comprehensive theory to treat the multi-component thermodynamic equilibria in the gas phase for several coexisting solid phases was developed and used. Many different processes to deposit various types of coatings on several types of steels were developed: Cr-Si codeposition for low- or medium-carbon steels, Cr-Al codeposition on low-carbon steels to yield either a Kanthal-type composition (Fe-25Cr-4Al in wt.%) or else a (Fe, Cr){sub 3}Al surface composition. An Fe{sub 3}Al substrate was aluminized to achieve an FeAl surface composition, and boron was also added to ductilize the coating. The developmental Cr-lean ORNL alloys with exceptional creep resistance were Cr-Al coated to achieve excellent oxidation resistance. Alloy wires of Ni-base were aluminized to provide an average composition of Ni{sub 3}Al for use as welding rods. Several different refractory metal alloys based on Cr-Cr{sub 2}Nb have been silicided, also with germanium additions, to provide excellent oxidation resistance. A couple of developmental Cr-Zr alloys were similarly coated and tested.
Date: March 10, 1998
Creator: Rapp, R. A.
Partner: UNT Libraries Government Documents Department

Bonding and hardness in nonhydrogenated carbon films with moderate sp(3) content

Description: Amorphous carbon films with an s p{sup 3} content up to 25% and a negligible amount of hydrogen have been grown by evaporation of graphite and concurrent Ar{sup +} ion bombardment. The s p{sup 3} content is maximized for Ar{sup +} energies between 200 and 300 eV following a subplantation mechanism. Higher ion energies deteriorate the film due to sputtering and heating processes. The hardness of the films increases in the optimal assisting range from 8 to 18 GPa, and is explained by the crosslinking of graphitic planes through s p {sup 3} connecting site.
Date: April 17, 2000
Partner: UNT Libraries Government Documents Department

Identification of silicone oil/PETN interaction. Quarterly report, January--March 1971

Description: Infrared and UV spectra have been obtained on oils pressed from GE5601 silicone rubber. A method for depositing oil on PETN has also been investigated. In order to determine if the oil was evenly deposited on the PETN, an analytical method was developed for determining the concentration of oil on PETN.
Date: September 1, 1997
Creator: Faubion, B.D.
Partner: UNT Libraries Government Documents Department

Rapid prototyping of patterned functional nanostructures

Description: Living systems exhibit form and function on multiple length scales, and the prospect of imparting life-like qualities to man-made materials has inspired many recent efforts to devise hierarchical materials assembly strategies. For example, Yang et al. grew surfactant-templated mesoporous silica on hydrophobic patterns prepared by micro-contact printing {micro}CP{sup 3}. Trau et al. formed oriented mesoporous silica patterns, using a micro-molding in capillaries MIMIC technique, and Yang et al. combined MIMIC, polystyrene sphere templating, and surfactant-templating to create oxides with three levels of structural order. Overall, great progress has been made to date in controlling structure on scales ranging from several nanometers to several micrometers. However, materials prepared have been limited to oxides with no specific functionality, whereas for many of the envisioned applications of hierarchical materials in micro-systems, sensors, waveguides, photonics, and electronics, it is necessary to define both form and function on several length scales. In addition, the patterning strategies employed thus far require hours or even days for completion. Such slow processes are inherently difficult to implement in commercial environments. The authors have combined evaporation-induced (silica/surfactant) self-assembly EISA with rapid prototyping techniques like pen lithography, ink-jet printing, and dip-coating on micro-contact printed substrates to form hierarchically organized structures in seconds. In addition, by co-condensation of tetrafunctional silanes (Si(OR){sub 4}) with tri-functional organosilanes ((RO){sub 3}SiR{prime}){sup 12--14} or by inclusion of organic additives, the authors have selectively derivatized the silica framework with functional R{prime} ligands or molecules. The resulting materials exhibit form and function on multiple length scales: on the molecular scale, functional organic moieties are positioned on pore surfaces, on the mesoscale, monosized pores are organized into 1-, 2-, or 3-dimensional networks, providing size-selective accessibility from the gas or liquid phase, and on the macroscale, 2-dimensional arrays and fluidic or photonic systems may be defined.
Date: February 9, 2000
Creator: Fan, Hongyou; Lu, Yunfeng; Stump, Aaron; Reed, Scott T.; Baer, Thomas A.; Schunk, P. Randall et al.
Partner: UNT Libraries Government Documents Department

Permeation Barrier Coatings for the Helical Heat Exchanger

Description: A permeation barrier coating was specified for the Helical Heat Exchanger (HHE) to minimize contamination through emissions and/or permeation into the nitrogen system for ALARA reasons. Due to the geometry of the HHE, a special coating practice was needed since the conventional method of high temperature pack aluminization was intractable. A survey of many coating companies was undertaken; their coating capabilities and technologies were assessed and compared to WSRC needs. The processes and limitations to coating the HHE are described. Slurry coating appears to be the most technically sound approach for coating the HHE.
Date: May 26, 1999
Creator: Korinko, P.S.
Partner: UNT Libraries Government Documents Department