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Reaction kinetics and x-ray absorption spectroscopy studies of yttrium containing metal hydride electrodes

Description: This was a study of electrode degradation mechanisms and the reaction kinetics of LaNi{sub 4.7}Sn{sub 0.3}, La{sub (1{minus}x)} Y{sub x}Ni{sub 4.7}Sn{sub 0.3} (x = 0.1, 0.2, and 0.3) and La{sub 0.7}Y{sub 0.3}Ni{sub 4.6}Sn{sub 0.3}Co{sub 0.1} metal hydride electrodes. Alloy characterization included x-ray diffraction (XRD), x-ray absorption (XAS), hydrogen absorption in a Sieverts apparatus, and electrochemical cycling of alloy electrodes. The atomic volume of H was determined for two of the alloys. Electrochemical kinetic measurements were made using steady state galvanostatic measurements, galvanodynamic sweep, and electrochemical impedance techniques. XAS was used to examine the degree of corrosion of the alloys with cycling. Alloying with Y decreased the corrosion rate. The results are consistent with corrosion inhibition by a Y containing passive film. The increase in the kinetics of the hydrogen oxidation reaction (HOR) with increasing depth of discharge was much greater on the Y containing alloys. This may be due to the dehydriding of the catalytic species on the surface of the metal hydride particles.
Date: December 31, 1998
Creator: Ticianelli, E.A.; Mukerjee, S.; McBreen, J.; Adzic, G.D.; Johnson, J.R. & Reilly, J.J.
Partner: UNT Libraries Government Documents Department

TEPIC - A New High Temperature Structural Foam

Description: The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 degrees C, are reported. In each of the respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. Compared to APO-BMI processing, TEPIC processing is facile and economical.
Date: unknown
Creator: Whinner, L. L.; Goods, S. H.; Tootle, M. L. & Neuschwanger, C. L.
Partner: UNT Libraries Government Documents Department

Fillability of Thin-Wall Steel Castings

Description: The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.
Date: July 30, 2002
Creator: Voigt, Robert C.; Bertoletti, Joseph; Kaley, Andrew; Ricotta, Sandi & Sunday, Travis
Partner: UNT Libraries Government Documents Department

New Manufacturing Method for Paper filler and Fiber Material

Description: The study compares commercial available filler products with a new developed “Hybrid Fiber Filler Composite Material” and how main structural, optical and strength properties are affected by increasing the filler content of at least 5% over commercial values. The study consists of: (i) an overview of paper filler materials used in the paper production process, (ii) discusses the manufacturing technology of lime based filler materials for paper applications, (iii) gives an overview of new emerging paper filler technologies, (iv) discusses a filler evaluation of commercial available digital printing paper products, (v) reports from a detailed handsheet study and 12” pilot plant paper machine trial runs with the new Hybrid Fiber Filler Composite Material, and (vi) evaluates and compares commercial filler products and the new Hybrid Fiber Filler Composite Material with a life cycle analyses that explains manufacturing, economic and environmental benefits as they are applied to uncoated digital printing papers.
Date: November 22, 2011
Creator: Doelle, Klaus
Partner: UNT Libraries Government Documents Department

Final Report: Stability and Novel Properties of Magnetic Materials and Ferromagnet / Insulator Interfaces

Description: We report investigations of the synthesis, structure, and properties of new materials for spintronic applications integrated onto silicon substrates. Our primary focus is materials with very high, negative, intrinsic spin polarization of the density of states at the Fermi level. We have developed a new synthesis method for Fe3O4 thin films through selective oxidation of Fe, resulting in smooth, low-defect density films. We have synthesized Fe4N films and shown that they preferentially oxidize to Fe3O4. When integrated into magnetic tunnel junctions consisting of Fe4N / AlOx / Fe, oxidation at the Fe4N / AlOx interface creates Fe3O4, leading to negative tunneling magnetoresistance (TMR). Oxidation of Fe in nominally symmetric CoFe / AlOx / CoFe also produces Fe3O4 and negative TMR under selected oxidation conditions.
Date: July 24, 2013
Creator: Voyles, Paul
Partner: UNT Libraries Government Documents Department

Non-Vacuum Electron Beam Welding

Description: Original objectives of CRADA number BNL-01-03 between BNL and Acceleron, Inc., were to further develop the Plasma Window concept (a BNL invention covered by US Patent number 5,578,831), mate the Plasma Window to an existing electron beam welder to perform in-air electron beam welding, and mount the novel nonvacuum electron beam welder on a robot arm. Except for the last objective, all other goals were met or exceeded. Plasma Window design and operation was enhanced during the project, and it was successfully mated to a conventional4 kW electron beam welder. Unprecedented high quality non-vacuum electron beam . welding was demonstrated. Additionally, a new invention the Plasma Shield (US Patent number 7,075,030) that chemically and thermally shields a target object was set forth. Great interest in the new technology was shown by a number of industries and three arcs were sold for experimental use. However, the welding industry requested demonstration of high speed welding, which requires 100 kW electron beam welders. The cost of such a welder involved the need for additional funding. Therefore, some of the effort was directed towards Plasma Shield development. Although relatively a small portion of the R&D effort was spent on the Plasma Shield, some very encouraging results were obtained. Inair Plasma Shield was demonstrated. With only a partial shield, enhanced vacuum separation and cleaner welds were realized. And, electron beam propagation in atmosphere improved by a factor of about 3. Benefits to industry are the introduction of two new technologies. BNL benefited from licensing fee cash, from partial payment for employee salary, and from a new patent In addition to financial benefits, a new technology for physics studies was developed. Recommendations for future work are to develop an under-water plasma shield, perform welding with high-power electron beam:s, carry out other plasma shielded electron beam and ...
Date: January 31, 2007
Creator: Hershcovitch, Ady
Partner: UNT Libraries Government Documents Department

Characterization of Optical Fiber Strength Under Applied Tensile Stress and Bending Stress

Description: Various types of tensile testing and bend radius tests were conducted on silica core/silica cladding optical fiber of different diameters with different protective buffer coatings, fabricated by different fiber manufacturers. The tensile tests were conducted to determine not only the average fiber strengths at failure, but also the distribution in fracture strengths, as well as the influence of buffer coating on fracture strength. The times-to-failure of fiber subjected to constant applied bending stresses of various magnitudes were measured to provide a database from which failure times of 20 years or more, and the corresponding minimum bend radius, could be extrapolated in a statistically meaningful way. The overall study was done to provide an understanding of optical fiber strength in tensile loading and in applied bending stress as related to applications of optical fiber in various potential coizfgurations for weapons and enhanced surveillance campaigns.
Date: August 1, 2011
Creator: Klingsporn, P.E.
Partner: UNT Libraries Government Documents Department

Material Design, Selection, and Manufacturing Methods for System Sustainment

Description: This paper describes a material selection and validation process proven to be successful for manufacturing high-reliability long-life product. The National Secure Manufacturing Center business unit of the Kansas City Plant (herein called KCP) designs and manufactures complex electrical and mechanical components used in extreme environments. The material manufacturing heritage is founded in the systems design to manufacturing practices that support the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA). Material Engineers at KCP work with the systems designers to recommend materials, develop test methods, perform analytical analysis of test data, define cradle to grave needs, present final selection and fielding. The KCP material engineers typically will maintain cost control by utilizing commercial products when possible, but have the resources and to develop and produce unique formulations as necessary. This approach is currently being used to mature technologies to manufacture materials with improved characteristics using nano-composite filler materials that will enhance system design and production. For some products the engineers plan and carry out science-based life-cycle material surveillance processes. Recent examples of the approach include refurbished manufacturing of the high voltage power supplies for cockpit displays in operational aircraft; dry film lubricant application to improve bearing life for guided munitions gyroscope gimbals, ceramic substrate design for electrical circuit manufacturing, and tailored polymeric materials for various systems. The following examples show evidence of KCP concurrent design-to-manufacturing techniques used to achieve system solutions that satisfy or exceed demanding requirements.
Date: February 18, 2010
Creator: David Sowder, Jim Lula, Curtis Marshall
Partner: UNT Libraries Government Documents Department

UV laser ablation of parylene films from gold substrates

Description: Parylene films, coating gold substrates, were removed by laser ablation using 248 nm light from an excimer laser. Each sample was processed by a different number of pulses in one of three different environments: air at atmospheric pressure, nitrogen at atmospheric pressure, and vacuum. The laser-induced craters were analyzed by optical microscopy and x-ray photoelectron spectroscopy. Multi-pulse ablation thresholds of gold and parylene were estimated.
Date: November 19, 2009
Creator: Musaev, O. R.; Scott, P.; Wrobel, J. M. & Kruger, M. B.
Partner: UNT Libraries Government Documents Department

Microstructural Characterization of 6061 Aluminum to 304L Stainless Steel Inertia Welds

Description: 'Microstructural characterization of 6061-T6 aluminum-to-Type 304L stainless steel inertia welds provided a technical basis to conclude that transition joints fabricated from such welds should satisfactorily contain helium/hydrogen gas mixtures. This conclusion is based on the lack of semi-continuous alignments of particles and/or inclusions at, or near, the aluminum-to-stainless steel interface. These dissimilar metal transition joints play a key role in the operation of an accelerator driven, spallation neutron source designed for the production of tritium. The Accelerator Production of Tritium system will produce tritium through neutron interactions with 3He gas contained in water-cooled, 6061-T6 aluminum pressure tubes. Current design concepts include thousands of thin-walled pressure tubes distributed throughout a number of aluminum-clad, lead-filled, blanket modules. The aluminum pressure tubes are connected to a tritium extraction and purification system through a stainless steel manifold. The transition from aluminum to stainless steel is made via transition joints machined from the aluminum-to-stainless steel inertia welds. The paper describes the baseline microstructural characterization of the welds, including optical, scanning and transmission electron microscopy and uses that characterization to evaluate potential gas leakage across the weld.'
Date: September 29, 1999
Creator: Dunn, K.A.
Partner: UNT Libraries Government Documents Department

Tabulation, bibliography, and structure of binary intermetallic compounds. III. Compounds of copper, silver and gold

Description: A review is given of the various transverse thermomagnetic and galvanomagnetic effects. The coefficicnts and relations between coefficients are listed for both metals and semiconductors. A quantitative annlysis is given of the error in Hall effcct measurements owing to non-isothermal conditions. (auth)
Date: September 9, 1957
Creator: Klepfer, H. H. & Shoemaker, H. E.
Partner: UNT Libraries Government Documents Department

Characterization of Mo/Si multilayer growth on stepped topographies

Description: Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growth, a continuum model has been developed to give a detailed description of the height profiles of the individual continuous layers. Complementary optical characterization of the multilayer system using a microscope operating in the extreme ultraviolet wavelength range, revealed that the influence of the step-edge on the planar multilayer structure is restricted to a region within 300 nm from the step-edge.
Date: August 31, 2011
Creator: van den Boogaard, A. J. R.; Louis, E.; Zoethout, E.; Goldberg, K. A. & Bijkerk, F.
Partner: UNT Libraries Government Documents Department

Effect of Grain Size on the Acoustic Emission Generated During Plastic Deformation of Aluminum

Description: Acoustic emission signals from polycrystalline Al 1100 samples during plastic deformation were analyzed with respect to the strain rate and grain size. A kinematic model is proposed to account for the observed behavior. An experimental acoustic emission parameter, equivalent to the average energy of the acoustic events, correlates satisfactorily with the computed energy of moving dislocations during the deformation process. Both energies attain a maximum value for a certain grain size, and are directly dependent on the strain rate.
Date: December 1, 1979
Creator: Baram, J. & Rosen, M.
Partner: UNT Libraries Government Documents Department

Correlation of Failure Times for Iodine SCC of Zircaloy

Description: A crack-growth model of stress corrosion cracking has been successfully applied to predict times-to-failure of zircaloy specimens exposed to iodine vapor. Data for two types of tests were analyzed using the model. The first was a variable loading experiment in which failure occurred after the specimen had been subjected to two distinct stresses in succession. The second was a series of tests in which surface roughness, and probably residual stress as well, was reduced by chemical polishing of the specimens. The success of the crack growth model in dealing with these situations suggests that crack propagation rather than crack initiation is the rate-controlling step in iodine stress corrosion cracking of zircaloy. Furthermore, the metal in the vicinity of the growing crack is apparently so embrittled by iodine that a model originally intended for ceramics applies.
Date: November 1, 1980
Creator: Shann, S. & Olander, D. R.
Partner: UNT Libraries Government Documents Department

Ferrite Structure and Mechanical Properties of Low Alloy Duplex Steels

Description: The purpose of this communication is threefold. 1) To confirm the presence of and to characterize the precipitates in the ferrite phase of the base + Nb and base + Mo steels, 2) to study any possible variation in precipitate density as the martensitic volume fraction is changed and 3) to determine the level of precipitation strengthening.
Date: April 1, 1981
Creator: Hoel, R. H. & Thomas, G.
Partner: UNT Libraries Government Documents Department

The Formation of Solid Solution Oxides During Internal Oxidation

Description: The diffusion processes occurring when binary alloys react with oxygen to form an oxide that contains both alloy components in solid solution, either exclusively as internal oxide or in combination with a surface scale, have been analyzed and compared with experimental results for Fe-Mn and Ni-Co alloys. The experimental results available for the Fe-Mn system were obtained under conditions of exclusive internal oxidation, and good agreement was obtained between calculated and experimental results. In the Ni-Co system, a surface scale and a zone of internal oxidation develop. Agreement between calculated and experimental depths of internal penetration is acceptable if the diffusivity of oxygen in the alloy is 3.8×10{sup −6} cm{sup 2}/sec at 1100°C. Agreement between calculated and experimental concentration profiles is not very good.
Date: September 1, 1980
Creator: Whittle, D. P.; Gesmundo, F.; Bastow, B. D. & Wood, G. C.
Partner: UNT Libraries Government Documents Department

The Erosion Behavior of Steel as a Function of Microstructure on Solid Particle Erosion

Description: The effects of the microstructure of two ductile steels on their solid particle erosion were determined. The steels chosen allowed microstructural changes to be made without drastically changing their hardness, which is reported to be a direct function of erosion resistance. The steels used were plain carbon 1075 and 1020 in the coarse pearlite, fine pearlite, and spheroidized forms for the 1075 and in three spherodized conditions for the 1020 steel. Single particle and multiple particle erosion tests were conducted using 240 {micro}m diameter SiC particles, angles of impingement of 15°, 30°, and 90° and velocities of 30.5 mps (100fps) and 61 mps (200fps). Both surface and subsurface analyses were conducted using scanning electron microscopy. In the room temperature erosion tests, the spheroidized microstructure of the 1075 steel eroded less than either of the two pearlitic microstructures. It was found that the pearlitic steels exhibited cracking at the eroded surface as well as beneath it, causing greater material removal. The spheroidized structure showed no surface cracking; however, cracking did occur at a depth of approximately 20 {micro}m below the surface. The carbide particle spacing in the 1020 spheroidized steel also had a measureable effect on the erosion rate, The hardness of the various microstructures had an inverse relation to the erosion rate,
Date: April 1, 1980
Creator: Levy, Alan V.
Partner: UNT Libraries Government Documents Department

Erosion Mechanism in Ductile Metals

Description: The removal of material from the surface of a ductile metal by small impacting particles is a design concern to the builders of synthetic fuels plants that utilize pulverized coal to produce gaseous forms of fuel. A series of room temperature experiments was conducted to determine the mechanism of material removal when an erosive particle stream impacts on a ductile metal surface. 1100-0 and 7075-T6 aluminum were used for the target and 600 {micro}m SiC particles moving at a velocity of 100 fps in air for the eroding stream. It was determined that a combined forging-extrusion mechanism at produces small, highly distressed platelets of tarrget material that are knocked off the surfce by succeeding particle impacts is responsible for erosion at both low and high impingement angles. The larrge strains that produce the platelets occur in a thin surface region which is heated near or to the annealing temperature of the metal as a result of adiabatic shear deformation. This hard, sub-surface layer, once formed, increases the efficiency of platelet formation at the surface and the erosion rate increases to a constant level. This propos mechanism is a significant departure from previously believed micromachining mechanism of erosion of ductile metals.
Date: June 1, 1980
Creator: Bellman, Robert, Jr. & Levy, Alan
Partner: UNT Libraries Government Documents Department

TEM AND RBS STUDIES OF SINGLE AND DOUBLE DISCRETE BURIED DAMAGE LAYERS IN P+ IMPLANTED Si ON SUBSEQUENT LASER ANNEALING

Description: This work is aimed at studying the regrowth behaviour of single and double buried damage layers on subsequent laser annealing of P{sup +) implanted Si, implanted at 120 keV to doses of 5 x 10{sup 14}/cm{sup 2} and 7.5 x10{sup 15}/cm{sup 2}, respectively. A Q-switched ruby laser operating at a wavelength of 0.695{micro}m was used for the annealing. 90{degrees} cross sectional TEM and MeV He{sup +} channelling spectroscopy were used to examine the damage structures and their depth distributions. At 0.9 J/cm{sup 2}, TEM results showed that the single buried damage layer regrew into two discrete damage layers. At 2.0 J/cm{sup 2}, TEM results showed that the first layer in the double buried damage layers type structures either completely annealout out, leaving a partially annealed second layer consisting of damage clusters or had dislocations in the first damage layer region that extended from the surface and were in direct contact with the deeper lying second layer of damage clusters. The MeV He{sup +} channelling spectra for the above samples were in agreement with the TEM results.
Date: January 1, 1980
Creator: Sadana, D. K.; Strathman, M.; Washburn, J. & Booker, G. R.
Partner: UNT Libraries Government Documents Department

Transformation Toughening in Ceramics

Description: The origin of transformation toughening in ceramics is examined using two separate approaches: one based on the stress field ahead of the crack and the other on the changes in thermodynamic potential during a crack increment. Both approaches yield essentially similar predictions of trends in toughness with particle size, temperature, composition, etc. The stress intensity analysis provides fully quantitative predictions of the toughness. These indicate that the shielding of the crack by the transformation zone only develops in the presence of a transformed wake, leading to R-curve behavior.
Date: December 1, 1980
Creator: Evans, A. G.; Marshall, D. B. & Burlingame, N. H.
Partner: UNT Libraries Government Documents Department

Transmission Electron Microscopy and Rutherford Backscattering Studies of Different Damage Structures in p+ Implanted Si

Description: 'Cross-sectional transmission electron microscopy (TEM)' and MeV He{sup +} channelling methods have been used to examine different damage structures present under the colour bands visible at the surface of a high dose rate P{sup +} implanted (111) Si implanted to a dose of 7.5 x 10{sup 15} ions/cm{sup 2}. TEM and channelling results obtained from individual coloured regions showed a good qualitative correlation in that discrete damage layers observed in the 'cross-sectional TEM' micrographs appeared as discrete peaks in the channelled spectra. The mean depths of the damage layers obtained from these two methods were in agreement. However, the widths of the deeper lying damage layers calculated from the channelling measurements were always greater than the widths observed by TEM. An emperical method based on subtraction of dechannelling background in the channelling spectra gave damage layer widths that were in close agreement with the TEM results.
Date: March 1, 1980
Creator: Sadana, D. K.; Strathman, M.; Washburn, J. & Booker, G. R.
Partner: UNT Libraries Government Documents Department

The Thermal Expansion of the Directionally Solidified Al-CuAl{Sub 2} Eutectic

Description: Alloys of Al- CuAl{sub 2} eutectic composition were prepared from 99.999% pure materials and directionally solidified in a temperature gradient of about 45°C/cm at different growth rates R. The {lambda}{sup 2}R = constant relation was verified and lamellar spacings of 7.5, 3.5, 2.6, 1.8 and 1.4 ~m were obtained. Dilatometer specimens were machined with axes aligned in the principal lamellae coordinate directions. Thermal expansion was measured by standard dilatometry (Cu standard) using a set point program cycling between room temperature and 500°C . Thermal expansion of the directionally solidified Al-CuAl{sub 2} eutectic is greatest in the growth direction (in the plane of the lamellae), least in the transverse direction (orthogonal to the growth direction in the plane of the lamellae) and intermediate in the vertical direction (normal to the lamellae) . The most significant finding of the study is that the thermal expansion increases with decreasing lamellar spacing between limits defined approximately by the thermal expansion of the CuAl{sub 2} phase alone and the predicted thermal expansion of an isotropic elastic model of the composite.
Date: March 1, 1980
Creator: Baker, Dennis F. & Bragg, Robert H.
Partner: UNT Libraries Government Documents Department

Thermodynamics of Low-Temperature (700-850{Degree}C) Hot Corrosion

Description: Existing phase diagrams in the systems Na{sub 2}SO{sub 4} - MSO}{sub 4} (M=Ni, Co) and Na{sub 2}SO{sub 4} - M{sub 2}(SO{sub 4}){sub 3} (M=Al, Fe, Cr) have been used to calculate the thermodynamic properties of the molten sulfate systems. The calculated thermodynamic data show satisfactory agreement with most of the available experimental observations. The calculations have shown that the activity of Al{sub 2}(SO{sub 4}){sub 3} and Fe{sub 2}(SO{sub 4}){sub 3} in the melt can be lowered to such an extent that liquid sulfate solutions can be formed at P{sub SO{sub 3}} levels that are prevalent in marine gas turbine operations, and this has been explained on the basis of complex formation in the melt. Thermodynamic analysis of the interaction of the Na{sub 2}SO{sub 4} - MSO{sub 4} (M=Co, Ni) melt with protective oxides Al{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} has demonstrated the vulnerability of Al-containing alloys to hot corrosion attack.
Date: September 1, 1980
Creator: Misra, A. K.; Whittle, D. P. & Worrell, W. L.
Partner: UNT Libraries Government Documents Department

The Thermoelastic Phase Transition in Au-Cd Alloys Studies by Acoustic Emission

Description: The acoustic emission generated during the thermoelastic phase transitions in polycrystalline Au-47.5 at.% Cd and in Au-49 at.% Cd alloys was recorded and analyzed. The emission detected is a manifestation of the frictional energy dissipated by the moving interfaces during the nucleation and growth stages of the reversible phase transitions. It was found that the amount of energy dissipated depends upon the direction of the transformation, the heating or cooling rates, and the specific crystallographic features of the martensitic phases. Premartensitic acoustic activity was detected in both alloys at temperatures of about 25 {degrees}C before the M{sub s} point. The dynamics and kinetics of martensitic thermoelastic phase transformations are discussed in terms of the accompanying generation of acoustic emission.
Date: March 1, 1980
Creator: Baram, I. & Rosen, M.
Partner: UNT Libraries Government Documents Department