Elevated-temperature flow strength, creep resistance and diffusion welding characteristics of Ti-gAl-2Nb-1Ta-0.8Mo

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Moore, T. J.

1977-01-01

A study of the flow strength, creep resistance and diffusion welding characteristics of the titanium alloy Ti-6Al-2Nb-1Ta-0.8Mo was conducted. Two mill-processed forms of this alloy were examined. The forged material was essentially processed above the beta transus while the rolled form was subjected to considerable work below the beta transus. Between 1150 and 1250 K, the forged material was stronger and more creep resistant than the rolled alloy. Both forms exhibit superplastic characteristics in this temperature range. Strain measurements during diffusion welding experiments at 1200 K reveal that weld interfaces have no measurable effect on the overall creep deformation. Significant deformation appears to be necessary to produce a quality diffusion weld between superplastic materials. A 'soft' interlayer inserted between faying surfaces would seemingly allow manufacture of quality diffusion welds with little overall deformation.

Solid-state Bonding of Superplastic Aluminum Alloy 7475 Sheet

NASA Technical Reports Server (NTRS)

Byun, T. D. S.; Vastava, R. B.

1985-01-01

Experimental works were carried out to study the feasibility of solid state bonding of superplastic aluminum 7475 sheet. Amount of deformation, bonding time, surface cleaning method and intermediate layer were the process parameters investigated. Other parameters, held constant by the superplastic forming condition which is required to obtain a concurrent solid state bonding, are bonding temperature, bonding pressure and atmosphere. Bond integrity was evaluated through metallographic examination, X-ray line scan analysis, SEM fractographic analysis and lap shear tests. The early results of the development program indicated that sound solid state bonding was accomplished for this high strength 7475 alloy with significant amounts of deformation. A thin intermediate layer of the soft 5052 aluminum alloy aided in achieving a solid state bonding by reducing the required amount of plastic deformation at the interface. Bond strength was substantially increased by a post bond heat treatment.

Fabricating Structural Stiffeners By Superplastic Forming

NASA Technical Reports Server (NTRS)

Bales, Thomas T.; Shinn, Joseph M., Jr.; Hales, Stephen J.; James, William F.

1994-01-01

Superplastic forming (SPF) of aluminum alloys effective technique for making strong, lightweight structural components conforming to close dimensional tolerances. Technique applied in experimental fabrication of prototypes of stiffening ribs for cylindrical tanks. When making structural panel, stiffening ribs spot-welded to metal skin. Use of discrete eliminates machining waste, and use of SPF. Cost of fabrication reduced.

Effects of plastic deformation on microstructure and superplasticity of the in situ Al3Ti/2024Al composites

NASA Astrophysics Data System (ADS)

Jiao, Lei; Yang, Yonggang; Li, Hui; Zhao, Yutao; Wang, Xiaolu

2018-05-01

In this study, the in situ Al3Ti/2024Al composites were successfully fabricated by direct melt reaction method and subjected to forging and friction stir processing (FSP) to achieve superplasticity. Then, the microstructure and superplastic tensile behavior of the composites were investigated. The results show that the reinforcement particles are broken and grains are fine after plastic processing. Particularly, the size of reinforcement particles ranges from 0.2 μm to 5 μm and the average size of fine equiaxed grains is 5 μm after FSP processing. And the superplasticity of the composites was improved apparently. The maximum elongation of 642% was obtained at 0.15 s‑1 and 510 °C for the FSP specimen, with a strain rate sensitive parameter (m) of 0.58, indicating the FSP specimen has obtained excellent high strain rate superplasticity. The strain rate sensitivity parameter, m, ranges from 0.23 to 0.58, and the activation energy was calculated to be 135.24 kJ mol‑1. All results indicated that the main superplastic deformation mechanism was grain boundary sliding (GBS) for the FSP Al3Ti/2024Al composites.

Fabrication and evaluation of superplastically formed/weld-brazed corrugated compression panels with beaded webs

NASA Technical Reports Server (NTRS)

Royster, D. M.; Davis, R. C.; Shinn, J. M., Jr.; Bales, T. T.; Wiant, H. R.

1985-01-01

A study was made to investigate the feasibility of superplastically forming corrugated panels with beaded webs and to demonstrate the structural integrity of these panels by testing. The test panels in the study consist of superplastically formed titanium alloy Ti-6Al-4V half-hat elements that are joined by weld-brazing to titanium alloy Ti-6Al-4V caps to form either single-corrugation compression panels or multiple-corrugation compression panels. Stretching and subsequent thinning of the titanium sheet during superplastic forming is reduced by approximately 35 percent with a shallow half-hat die concept instead of a deep die concept and results in a more uniform thickness across the beaded webs. The complete panels are tested in end compression at room temperature and the results compared with analysis. The heavily loaded panels failed at loads approaching the yield strength of the titanium material. At maximum load, the caps wrinkled locally accompanied with separation of the weld-braze joint in the wrinkle. None of the panels tested, however, failed catastrophically in the weld-braze joint. Experimental test results are in good agreement with structural analysis of the panels.

Elevated temperature flow strength, creep resistance and diffusion welding characteristics of Ti-6Al-2Nb-1Ta-0.8Mo

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Moore, T. J.

1979-01-01

A study of the flow strength, creep resistance and diffusion welding characteristics of the titanium alloy Ti-6Al-2Nb-1Ta-0.8Mo has been conducted. Two mill-processed forms of this alloy were examined. The forged material had been processed above the beta transus (approximately 1275 K) while the rolled form had been subjected to work below the beta transus. Between 1150 and 1250 K, the forged material was stronger and more creep resistant than the rolled alloy. Both forms exhibit superplastic characteristics in this temperature range. Strain measurements during diffusion welding experiments at 1200 K reveal that weld interfaces have no measurable effect on the overall creep deformation. Significant deformation appears to be necessary to produce a quality diffusion weld between superplastic materials. A 'soft' interlayer inserted between faying surfaces would seemingly allow manufacture of quality diffusion welds with little overall deformation.

Recrystallization and superplasticity at 300 C in an aluminum-magnesium alloy

NASA Technical Reports Server (NTRS)

Hales, S. J.; Mcnelley, T. R.; Mcqueen, H. J.

1991-01-01

Variations in thermomechanical processing (TMP) which regulate the microstructural characteristics and superplastic response of an Al-10Mg-0.1Zr alloy at 300 C were evaluated. Mechanical property data revealed that the superplastic ductility can be enhanced by simultaneously increasing the total rolling strain, the reduction per pass, and the duration of reheating intervals between passes during isothermal rolling. Texture and microscopy data were consistent with the development of a refined microstructure by recovery-dominated processes, i.e., continuous recrystallization, during the processing. The mechanisms by which a refined substructure can be progressively converted into a fine-grained structure during repeated cycles of deformation and annealing are addressed. A qualitative description of the complex sequence of developments leading to a microstructure better suited to support superplastic response is presented.

Cavitation During Superplastic Forming

PubMed Central

Campbell, John

2011-01-01

Cavitation is the opening of pores during superplastic forming, typically at grain boundary triple points or on second phase grain boundary particles during slip of grain boundaries. Theories for the initiation of cavitation are reviewed. It seems that cavitation is unlikely to occur by processes intrinsic to metals such as dislocation mechanisms or point defect condensation. It is proposed that cavitation can only occur at non-bonded interfaces such as those introduced extrinsically (i.e., from the outside) during the original casting of the metal. These defects, known as oxide bifilms, are naturally introduced during pouring of the liquid metal, and are frozen into the solid, often pushed by dendritic growth into grain boundaries where they are difficult to detect because of their extreme thinness, often measured in nanometres. Their unbonded central interface acts as a crack and can initiate cavitation. Second phase precipitates probably do not nucleate and grow on grain boundaries but grow on bifilms in the boundaries, explaining the apparent association between boundaries, second phase particles and failure initiation. Improved melting and casting techniques can provide metal with reduced or zero bifilm population for which cavitation would not be possible, promising significant improvements in superplastic behaviour. PMID:28824142

Cavitation During Superplastic Forming.

PubMed

Campbell, John

2011-07-08

Cavitation is the opening of pores during superplastic forming, typically at grain boundary triple points or on second phase grain boundary particles during slip of grain boundaries. Theories for the initiation of cavitation are reviewed. It seems that cavitation is unlikely to occur by processes intrinsic to metals such as dislocation mechanisms or point defect condensation. It is proposed that cavitation can only occur at non-bonded interfaces such as those introduced extrinsically (i.e., from the outside) during the original casting of the metal. These defects, known as oxide bifilms, are naturally introduced during pouring of the liquid metal, and are frozen into the solid, often pushed by dendritic growth into grain boundaries where they are difficult to detect because of their extreme thinness, often measured in nanometres. Their unbonded central interface acts as a crack and can initiate cavitation. Second phase precipitates probably do not nucleate and grow on grain boundaries but grow on bifilms in the boundaries, explaining the apparent association between boundaries, second phase particles and failure initiation. Improved melting and casting techniques can provide metal with reduced or zero bifilm population for which cavitation would not be possible, promising significant improvements in superplastic behaviour.

Continuous recrystallization during thermomechanical processing of a superplastic Al-10Mg-0.1Zr alloy

NASA Technical Reports Server (NTRS)

Hales, S. J.; Mcnelley, T. R.; Crooks, R.

1990-01-01

Microstructural evolution via static continuous recrystallization during thermomechanical processing of an Al-Mg-Zr alloy is addressed. Mechanical property data demonstrated that as-rolled material was capable of superplastic response without further treatment. Further, superplastic ductility at 300 C was enhanced by a factor of five by increasing the reheating time between rolling passes during processing also at 300 C. This enhanced ductility was associated with a Cu-texture and a microstructure consisting of predominantly high-angle boundaries. Processing to minimize recovery resulted in a strong Brass-texture component, a predominantly low-angle boundary microstructure and poorer ductility.

Diffusion bonding aeroengine components

NASA Astrophysics Data System (ADS)

Fitzpatrick, G. A.; Broughton, T.

1988-10-01

The use of diffusion bonding processes at Rolls-Royce for the manufacture of titanium-alloy aircraft engine components and structures is described. A liquid-phase diffusion bonding process called activated diffusion bonding has been developed for the manufacture of the hollow titanium wide chord fan blade. In addition, solid-state diffusion bonding is being used in the manufacture of hollow vane/blade airfoil constructions mainly in conjunction with superplastic forming and hot forming techniques.

Manifold free multiple sheet superplastic forming

DOEpatents

Elmer, John W.; Bridges, Robert L.

2001-01-01

Fluid-forming compositions in a container attached to enclosed adjacent sheets are heated to relatively high temperatures to generate fluids (gases) that effect inflation of the sheets. Fluid rates to the enclosed space between the sheets can be regulated by the canal from the container. Inflated articles can be produced by a continuous, rather than batch-type, process.

Manifold free multiple sheet superplastic forming

DOEpatents

Elmer, John W.; Bridges, Robert L.

2004-01-13

Fluid-forming compositions in a container attached to enclosed adjacent sheets are heated to relatively high temperatures to generate fluids (gases) that effect inflation of the sheets. Fluid rates to the enclosed space between the sheets can be regulated by the canal from the container. Inflated articles can be produced by a continuous, rather than batch-type, process.

Joining of advanced materials by superplastic deformation

DOEpatents

Goretta, Kenneth C.; Routbort, Jules L.; Gutierrez-Mora, Felipe

2008-08-19

A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

Joining of advanced materials by superplastic deformation

DOEpatents

Goretta, Kenneth C.; Routbort, Jules L.; Gutierrez-Mora, Felipe

2005-12-13

A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

Superplastic formability of Al-Cu-Li alloy Weldalite (TM) 049

NASA Technical Reports Server (NTRS)

Ma, Bao-Tong; Pickens, Joseph R.

1991-01-01

Extensive research during the past decade shows that several aluminum lithium alloys can be processed to attain a microstructure that enables superplasticity. The high tensile stress of Al-Cu-Li alloy Weldalite (TM) 049 in the T4 and T6 tempers offers tremendous potential for attaining exceptional post-SPF (superplastic formability) properties. The used SPF material is Weldalite, which was shown to induce SPF behavior in other Al-Cu-Li alloys. The superplastic behavior and resulting post-SPF mechanical properties of this alloy, which was designed to be the next major structural alloy for space applications, were evaluated. The results indicate that Weldalite alloy does indeed exhibit excellent superplasticity over a wide range of temperatures and strain rates and excellent post-SPF tensile strength at various potential service temperatures.

High-strain-rate superplasticity of the Al-Zn-Mg-Cu alloys with Fe and Ni additions

NASA Astrophysics Data System (ADS)

Kotov, A. D.; Mikhaylovskaya, A. V.; Borisov, A. A.; Yakovtseva, O. A.; Portnoy, V. K.

2017-09-01

During high-strain-rate superplastic deformation, superplasticity indices, and the microstructure of two Al-Zn-Mg-Cu-Zr alloys with additions of nickel and iron, which contain equal volume fractions of eutectic particles of Al3Ni or Al9FeNi, have been compared. It has been shown that the alloys exhibit superplasticity with 300-800% elongations at the strain rates of 1 × 10-2-1 × 10-1 s-1. The differences in the kinetics of alloy recrystallization in the course of heating and deformation at different temperatures and rates of the superplastic deformation, which are related to the various parameters of the particles of the eutectic phases, have been found. At strain rates higher than 4 × 10-2, in the alloy with Fe and Ni, a partially nonrecrystallized structure is retained up to material failure and, in the alloy with Ni, a completely recrystallized structure is formed at rates of up to 1 × 10-1 s-1.

Constitutive Equation with Varying Parameters for Superplastic Flow Behavior

NASA Astrophysics Data System (ADS)

Guan, Zhiping; Ren, Mingwen; Jia, Hongjie; Zhao, Po; Ma, Pinkui

2014-03-01

In this study, constitutive equations for superplastic materials with an extra large elongation were investigated through mechanical analysis. From the view of phenomenology, firstly, some traditional empirical constitutive relations were standardized by restricting some strain paths and parameter conditions, and the coefficients in these relations were strictly given new mechanical definitions. Subsequently, a new, general constitutive equation with varying parameters was theoretically deduced based on the general mechanical equation of state. The superplastic tension test data of Zn-5%Al alloy at 340 °C under strain rates, velocities, and loads were employed for building a new constitutive equation and examining its validity. Analysis results indicated that the constitutive equation with varying parameters could characterize superplastic flow behavior in practical superplastic forming with high prediction accuracy and without any restriction of strain path or deformation condition, showing good industrial or scientific interest. On the contrary, those empirical equations have low prediction capabilities due to constant parameters and poor applicability because of the limit of special strain path or parameter conditions based on strict phenomenology.

Evaluation of superplastic forming and co-diffusion bonding of Ti-6Al-4V titanium alloy expanded sandwich structures

NASA Technical Reports Server (NTRS)

Arvin, G. H.; Israeli, L.; Stolpestad, J. H.; Stacher, G. W.

1981-01-01

The application of the superplastic forming/diffusion bonding (SPF/DB) process to supersonic cruise research is investigated. The capability of an SPF/DB titanium structure to meet the structural requirements of the inner wing area of the NASA arrow-wing advanced supersonic transport design is evaluated. Selection of structural concepts and their optimization for minimum weight, SPF/DB process optimization, fabrication of representative specimens, and specimen testing and evaluation are described. The structural area used includes both upper and lower wing panels, where the upper wing panel is used for static compression strength evaluation and the lower panel, in tension, is used for fracture mechanics evaluations. The individual test specimens, cut from six large panels, consist of 39 static specimens, 10 fracture mechanics specimens, and one each full size panel for compression stability and fracture mechanics testing. Tests are performed at temperatures of -54 C (-65 F), room temperature, and 260 C (500 F).

Superplastic Forming of Duplex Stainless Steel for Aerospace Part

NASA Astrophysics Data System (ADS)

Lee, Ho-Sung; Yoon, Jong-Hoon; Yoo, Joon-Tae; Yi, Young-Moo

2011-08-01

In this study, the high temperature forming behavior of duplex stainless steel has been characterized and the outer shell of a combustion chamber was fabricated with pressure difference of hot gas. It consists of two parts which are the outer skin made of stainless steel to sustain the internal pressure and the inner shell made of copper alloy for regenerative cooling channels. Two outer skins partitioned to half with respect to the symmetric axis was prepared by hot gas forming process with a maximum pressure of 7 MPa following to FEM analysis. For inner layer, copper alloy was machined for cooling channels and then placed in the gas pressure welding fixture. It is shown that the optimum condition of gas pressure welding is 7 MPa at 890 °C, for one hour. EDX analysis and scanning electron microscope micrograph confirm the atomic diffusion process is observed at the interface and copper atoms diffuse into steel, while iron and chrome atoms diffuse into copper. The result shows that the manufacturing method with superplastic forming and gas pressure welding of steel and copper alloy has been successful for near net shape manufacturing of scaled combustion chamber of launch vehicle.

Improvement of Superplasticity in High-Mg Aluminum Alloys by Sacrifice of Some Room Temperature Formability

NASA Astrophysics Data System (ADS)

Jin, H.; Amirkhiz, B. Shalchi; Lloyd, D. J.

2018-03-01

The mechanical properties of fully annealed Al-4.6 wt pct Mg alloys with different levels of Mn and Fe have been characterized at room and superplastic forming (SPF) temperatures. The effects of Mn and Fe on the intermetallic phase, grain structure, and cavitation were investigated and correlated to the formability at different temperatures. Although both Mn and Fe contribute to the formation of Al6(Mn,Fe) phase, which refines the grain structure by particle-stimulated nucleation and Zener pinning, their effects are different. An increasing Mn reduces the room temperature formability due to the increasing number of intermetallic particles, but significantly improves the superplasticity by fine grain size-induced grain boundary sliding. Meanwhile, the Fe makes the constituent particles very coarse, resulting in reduced formability at all temperatures due to extensive cavitation. A combination of high Mn and low Fe is therefore beneficial to SPF, while low levels of both elements are good for cold forming. Consequently, the superplasticity of high-Mg aluminum alloys can be significantly improved by modifying the chemical composition with sacrifice of some room temperature formability.

Strength enhancement process for prealloyed powder superalloys

NASA Technical Reports Server (NTRS)

Waters, W. J.; Freche, J. C.

1977-01-01

A technique involving superplastic processing and high pressure autoclaving was applied to a nickel base prealloyed powder alloy. Tensile strengths as high as 2865 MN/sq m at 480 C were obtained with as-superplastically deformed material. Appropriate treatments yielding materials with high temperature tensile and stress rupture strengths were also devised.

Variation of strain rate sensitivity index of a superplastic aluminum alloy in different testing methods

NASA Astrophysics Data System (ADS)

Majidi, Omid; Jahazi, Mohammad; Bombardier, Nicolas; Samuel, Ehab

2017-10-01

The strain rate sensitivity index, m-value, is being applied as a common tool to evaluate the impact of the strain rate on the viscoplastic behaviour of materials. The m-value, as a constant number, has been frequently taken into consideration for modeling material behaviour in the numerical simulation of superplastic forming processes. However, the impact of the testing variables on the measured m-values has not been investigated comprehensively. In this study, the m-value for a superplastic grade of an aluminum alloy (i.e., AA5083) has been investigated. The conditions and the parameters that influence the strain rate sensitivity for the material are compared with three different testing methods, i.e., monotonic uniaxial tension test, strain rate jump test and stress relaxation test. All tests were conducted at elevated temperature (470°C) and at strain rates up to 0.1 s-1. The results show that the m-value is not constant and is highly dependent on the applied strain rate, strain level and testing method.

Finite Element Simulations for Investigating the Effects of Specimen Geometry in Superplastic Tensile Tests

NASA Astrophysics Data System (ADS)

Nazzal, Mohammad; Abu-Farha, Fadi; Curtis, Richard

2011-08-01

Characterizing the behavior of superplastic materials is largely based on the uniaxial tensile test; yet the unique nature of these materials requires a particularly tailored testing methodology, different to that used with conventional materials. One of the crucial testing facets is the specimen geometry, which has a great impact on the outcome of a superplastic tensile test, as a result of the associated extreme conditions. And while researchers agree that it should take a notably different form than the typical dog-bone shape; there is no universal agreement on the specimen's particular size and dimensions, as evident by the disparities in test specimens used in the various superplastic testing efforts found throughout the literature. In view of that, this article is dedicated to understanding the effects of specimen geometry on the superplastic behavior of the material during tensile testing. Deformation of the Ti6Al4V titanium alloy is FE simulated based on a multitude of specimen geometries, covering a wide range of gauge length, gauge width, grip length, and grip width values. The study provides key insights on the influences of each geometrical parameter as well as their interactions, and provides recommendations on selecting the specimen's proportions for accurate and unified tensile testing of superplastic materials.

Elastic constants for superplastically formed/diffusion-bonded corrugated sandwich core

NASA Technical Reports Server (NTRS)

Ko, W. L.

1980-01-01

Formulas and associated graphs for evaluating the effective elastic constants for a superplastically formed/diffusion bonded (SPF/DB) corrugated sandwich core, are presented. A comparison of structural stiffnesses of the sandwich core and a honeycomb core under conditions of equal sandwich core density was made. The stiffness in the thickness direction of the optimum SPF/DB corrugated core (that is, triangular truss core) is lower than that of the honeycomb core, and that the former has higher transverse shear stiffness than the latter.

Friction Stir Processing of As-Cast AA5083: Superplastic Response

DTIC Science & Technology

2009-06-01

3 A. ALUMINUM ALLOY 5083............................................................................3 B. SUPERPLASTICITY...ALUMINUM ALLOY 5083 The United States Navy is always considering the most effective and cost effective materials and manufacturing processes. These...desires have lead to a long-term interest in aluminum alloys for naval shipbuilding and design. The 5 -series aluminum alloys (Al-Mg system) are widely

Indirect Versus Direct Heating of Sheet Materials: Superplastic Forming and Diffusion Bonding Using Lasers

NASA Astrophysics Data System (ADS)

Jocelyn, Alan; Kar, Aravinda; Fanourakis, Alexander; Flower, Terence; Ackerman, Mike; Keevil, Allen; Way, Jerome

2010-06-01

Many from within manufacturing industry consider superplastic forming (SPF) to be ‘high tech’, but it is often criticized as too complicated, expensive, slow and, in general, an unstable process when compared to other methods of manipulating sheet materials. Perhaps, the fundamental cause of this negative perception of SPF, and also of diffusion bonding (DB), is the fact that the current process of SPF/DB relies on indirect sources of heating to produce the conditions necessary for the material to be formed. Thus, heat is usually derived from the electrically heated platens of hydraulic presses, to a lesser extent from within furnaces and, sometimes, from heaters imbedded in ceramic moulds. Recent evaluations of these isothermal methods suggest they are slow, thermally inefficient and inappropriate for the process. In contrast, direct heating of only the material to be formed by modern, electrically efficient, lasers could transform SPF/DB into the first choice of designers in aerospace, automotive, marine, medical, architecture and leisure industries. Furthermore, ‘variable temperature’ direct heating which, in theory, is possible with a laser beam(s) may provide a means to control material thickness distribution, a goal of enormous importance as fuel efficient, lightweight structures for transportation systems are universally sought. This paper compares, and contrasts, the two systems and suggests how a change to laser heating might be achieved.

Superplasticity of Annealed H13 Steel

PubMed Central

Duan, Zhenxin; Pei, Wen; Gong, Xuebo; Chen, Hua

2017-01-01

H13 steel is a widely used hot work die material. A new type of hot working method is imperative to develop complex and precise dies. In this paper, the heat treatment of H13 steel (AISI) was carried out by annealing, the final structure is a point or spherical pearlite, and the grain size is about 30–40 μm. The tensile properties of the annealed microstructure were investigated at 650, 750, and 850 °C with the strain rates of 1 × 10−3 s−1, 5 × 10−4 s−1, and 1 × 10−4 s−1. The tensile fracture and microstructure were analyzed by SEM and HREM. The results show that the tensile samples reach superplasticity at the strain rate of 1 × 10−4 s−1 in the temperature range of 750–850 °C. When the temperature is 850 °C, the maximum elongation rate reaches 112.5%. This demonstrates the possibility of making superplastic forming molds. During the tensile process, the refined M23C6 and other high hardness carbides which are dispersed uniformly in the matrix, effectively inhibits grain growth and hinders dislocation movement, leading to the improvement of plasticity. PMID:28773231

Phase state of a Bi-43 wt % Sn superplastic alloy and its changes under the effect of external mechanical stresses and aging

NASA Astrophysics Data System (ADS)

Korshak, V. F.; Chushkina, R. A.; Shapovalov, Yu. A.; Mateichenko, P. V.

2011-07-01

Samples of a Bi-43 wt % Sn superplastic alloy have been studied by X-ray diffraction in the ascast state, after compression of as-cast samples to ˜70% on a hydraulic press, after aging in the as-cast and preliminarily compressed state, and using samples deformed under superplastic conditions. The X-ray diffraction studies have been carried out using a DRON-2.0 diffractometer in Cu Kα radiation. The samples aged and deformed under superplasticity conditions have been studied using electron-microprobe analysis in a JSM-820 scanning electron microscope equipped with a LINK AN/85S EDX system. It has been found that the initial structural-phase state of the alloy was amorphous-crystalline. Causes that lead to a change in this state upon deformation and aging are discussed. A conclusion is made that the superplasticity effect manifests itself against the background of processes that are stipulated by the tendency of the initially metastable alloy to phase equilibrium similarly to what is observed in the Sn-38 wt % Pb eutectic alloy studied earlier.

Study of the properties and the choice of alloys for bladed disks (blisks) and a method for their joining

NASA Astrophysics Data System (ADS)

Povarova, K. B.; Valitov, V. A.; Obsepyan, S. V.; Drozdov, A. A.; Bazyleva, O. A.; Valitova, E. V.

2014-09-01

The choice of materials for the bladed disks (blisks) that are intended for next-generation aviation gas turbine engines is grounded. As blade materials, single crystals of light heterophase γ' + γ VKNA-type alloys based on the γ'(Ni3Al) intermetallic compound with an ordered structure are proposed. The choice of novel deformable EP975-type nickel superalloys, which are intended for operation at 800-850°C, as the disk material is grounded. It is shown that the most effective method for forming one-piece joints of an Ni3Al-based alloy and a high-alloy EP975-type nickel superalloy is the new process of solid-phase pressure welding under conditions of high-temperature superplasticity. Solid-phase joints are formed for heterophase Ni3Al-based alloy single crystals and deformable EK61 and EP975 nickel alloys. The gradient structures in the zone of the solid-phase joints that form under the conditions of low- and high-temperature superplasticity at homologous temperatures of ˜0.6 T m and 0.9 T m are studied. The character and direction of the diffusion processes at the joint of an intermetallic alloy single crystal and a deformable polycrystalline alloy are determined.

Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

PubMed Central

Matsushita, Masafumi

2011-01-01

Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride. PMID:28824144

Novel Routes for Sintering of Ultra-high Temperature Ceramics and their Properties

DTIC Science & Technology

2014-10-31

UHTCs charge (zirconium and hafnium borides , SiC) with additives (chromium carbide, nickel, chromium, etc.), which activate sintering process, is...temperature phases in a form of carboborides of zirconium and bi borides of zirconium or chromium. Elevation of densification rate of sintered borides is...superplasticity under the slip mechanism of zirconium boride and silica carbide grains on grain boundary interlayers with nanocrystalline grains of carbon

Manufacture of a four-sheet complex component from different titanium alloys by superplastic forming

NASA Astrophysics Data System (ADS)

Allazadeh, M. R.; Zuelli, N.

2017-10-01

A superplastic forming (SPF) technology process was deployed to form a complex component with eight-pocket from a four-sheet sandwich panel sheetstock. Six sheetstock packs were composed of two core sheets made of Ti-6Al-4V or Ti-5Al-4Cr-4Mo-2Sn-2Zr titanium alloy and two skin sheets made of Ti-6Al-4V or Ti-6Al-2Sn-4Zr-2Mo titanium alloy in three different combinations. The sheets were welded with two subsequent welding patterns over the core and skin sheets to meet the required component's details. The applied welding methods were intermittent and continuous resistance seam welding for bonding the core sheets to each other and the skin sheets over the core panel, respectively. The final component configuration was predicted based on the die drawings and finite element method (FEM) simulations for the sandwich panels. An SPF system set-up with two inlet gas pipe feeding facilitated the trials to deliver two pressure-time load cycles acting simultaneously which were extracted from FEM analysis for specific forming temperature and strain rate. The SPF pressure-time cycles were optimized via GOM scanning and visually inspecting some sections of the packs in order to assess the levels of core panel formation during the inflation process of the sheetstock. Two sets of GOM scan results were compared via GOM software to inspect the surface and internal features of the inflated multisheet packs. The results highlighted the capability of the tested SPF process to form complex components from a flat multisheet pack made of different titanium alloys.

Superplastic Forming/Diffusion Bonding Without Interlayer of 5A90 Al-Li Alloy Hollow Double-Layer Structure

NASA Astrophysics Data System (ADS)

Jiang, Shaosong; Jia, Yong; Lu, Zhen; Shi, Chengcheng; Zhang, Kaifeng

2017-09-01

The hollow double-layer structure of 5A90 Al-Li alloy was fabricated by SPF/DB process in this study. The characteristics and mechanism of 5A90 Al-Li alloy with respect to superplasticity and diffusion bonding were investigated. Tensile tests showed that the optimal elongation of tensile specimens was 243.97% at the temperature of 400 °C and the strain rate of 0.001 s-1. Effect of the surface roughness, bonding temperature and bonding time to determine the microstructure and mechanical properties of diffusion bonding joints was investigated, and the optimum bonding parameters were 540 °C/2.5 h/Ra18. Through the finite element simulation, it could be found that the SPF/DB process of hollow double-layer structure was feasible. The hollow double-layer structure of 5A90 Al-Li alloy was manufactured, showing that the thickness distribution of the bonding area was uniform and the thinnest part was the round corner. The SEM images of diffusion bonding joints showed that sound bonding interfaces were obtained in which no discontinuity existed.

Materials Research for High Speed Civil Transport and Generic Hypersonics-Metals Durability

NASA Technical Reports Server (NTRS)

Schulz, Paul; Hoffman, Daniel

1996-01-01

This report covers a portion of an ongoing investigation of the durability of titanium alloys for the High Speed Civil Transport (HSCT). Candidate alloys need to possess an acceptable combination of properties including strength and toughness as well as fatigue and corrosion resistance when subjected to the HSCT operational environment. These materials must also be capable of being processed into required product forms while maintaining their properties. Processing operations being considered for this airplane include forming, welding, adhesive bonding, and superplastic forming with or without diffusion bonding. This program was designed to develop the material properties database required to lower the risk of using advanced titanium alloys on the HSCT.

Superplastic flow lubricates carbonate faults during earthquake slip

NASA Astrophysics Data System (ADS)

De Paola, Nicola; Holdsworth, Robert; Viti, Cecilia; Collettini, Cristiano; Faoro, Igor; Bullock, Rachael

2014-05-01

Tectonic earthquakes are hosted in the shallower portion of crustal fault zones, where fracturing and cataclasis are thought to be the dominant processes during frictional sliding. Aseismic shear in lower crust and lithospheric mantle shear zones is accomplished by crystal plasticity, including superplastic flow acting at low strain rates on ultrafine-grained rocks. Superplasticity has also been observed at high strain rates for a range of nano-phase alloys and ceramics, and could potentially occur in fine-grained geological materials, if deformed at high strain rates and temperatures. We performed a set of displacement-controlled experiments to explore whether superplastic flow can effectively weaken faults, and facilitate earthquake propagation. The experiments were performed on fine-grained synthetic gouges (63 < f < 93 μm) of undeformed, protolith carbonate rocks using a rotary shear apparatus, at target speed v = 1 ms-1, normal stresses σn = 12-18 MPa, displacements d from 0.009 to 1.46 m, room temperature and humidity conditions. Samples were recovered after each experiment to study the slip zone microstructures. The integration of experimental data and microstructural observations shows that during sliding at seismic velocity, brittle fracturing and cataclasis control shear localization and grain size reduction in the slip zone at relatively low temperatures (T ≤ 100 °C). Stress levels predicted by such behaviours match those measured during the experiments. As temperatures rise due to frictional heating (T ≥ 500 °C), dislocation creep mechanisms start to accommodate intragranular strain, and play a key role in producing nanoscale subgrains (< 200 nm) in the slip zone. At this stage, despite of the presence of nanoparticles in the slip zone and the attainment of seismic slip rates, the measured frictional strength of experimental faults still lies within Byerlee's range of values μ = 0.8. This suggests that the slip zone bulk strength at this stage is controlled by cataclastic frictional sliding rather than by dislocation creep or nanopowder lubrication mechanisms. When T ≥ 800 °C are attained, micro-textures diagnostic of diffusion-dominated grain boundary sliding are widespread within the slip zone, and suggest bulk superplastic flow. Flow stresses predicted by superplasticity constitutive laws at the slip zone temperatures, grain sizes and strain rates attained during the experiments match those we measured in the laboratory (μ = 0.16). We propose therefore that the activation of diffusion creep at high temperatures (T ≥ 800 °C) leads to slip zone-localised superplastic flow and that this causes the dynamic weakening of carbonate faults at seismic slip rates. Note, however, that both cataclasis and dislocation creep operating at lower temperatures, during the earlier stages of slip, are critical, precursory processes needed to produce the nanoscale grain sizes required to activate grainsize sensitive mechanisms during superplastic flow. Finally, the re-strengthening observed during the decelerating phase of deformation can be explained by the falling temperature "switching off" slip zone-localized superplasticity, leading to a return to frictional sliding. These results indicate that superplastic flow can effectively weaken faults, and facilitate earthquake propagation in the upper crust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kral, Petr, E-mail: pkral@ipm.cz; CEITEC – IPM ASCR, v.v.i., Zizkova 22, CZ-61662 Brno; Dvorak, Jiri

The deformation kinetics of ultrafine-grained Ti-6Al-4V with mean (sub)grain size about 150 nm (produced by isothermal multiaxial forging) and superplastic properties at the relatively low temperature of 873 K was investigated in compression and tension over a large range of strain rates from 10{sup −7} to 10{sup −2} s{sup −1}. Electron microscopic observations showed that the grains coarsen during deformation towards the quasi-stationary spacing w{sub qs} of strain induced boundaries. In spite of the grain coarsening the grains were generally smaller than w{sub qs} allowing high-angle boundaries to dominate the quasi-stationary strength. Texture measurements indicate that dislocation glide plays amore » large role in deformation. Glide in this alloy is significantly influenced by solid solution strengthening leading to a stress sensitivity of strain rate of n = 3. The present ultrafine-grained Ti alloy displays a stress sensitivity exponent n = 2 over an extended stress range where its superplastic behavior is optimal. While the deformation kinetics of present ultrafine-grained Ti alloy can be roughly explained by the traditional formula for superplastic flow, the significant discrepancy to the measured values suggests that solid solution strengthening must be taken into account to get a complete insight. - Highlights: • The UFG Ti-6Al-4V alloy behaves superplastically at low temperature of 873 K. • Grain coarsening at low stresses limits superplasticity of UFG Ti alloy. • Solute strengthening plays an important role in low-temperature superplasticity. • Acceleration of creep in UFG Ti alloy is caused by processes related to hab.« less

Advanced high-temperature alloys: Processing and properties; Proceedings of the Nicholas J. Grant Symposium, MIT, Cambridge, MA, June 16-18, 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, S.M.; Pelloux, R.M.; Widmer, R.

1986-01-01

Historical and advanced methods of producing, forming and polishing alloys in billets and net shapes are explored. Attention is given to the deficiencies in arc furnace melts and to the benefits which are accruing from rapid solidification processing, powder metallurgy and superplastic forming. The techniques employed in these methods for processing materials to desired shapes, mainly for aircraft gas turbine engines, are described, along with the microstructures and mechanical properties which are obtained. The state of the art in casting and forming techniques which yield the most favorable properties in intermetallic compound-based alloys, superalloys, glasses and metacrystals are identified. Finally,more » research directions being pursued to obtain higher purity, enhanced temperature, longer lifetime, damage resistant alloys which can be formed to net shapes are discussed.« less

Processing and Properties of Airframe Materials.

DTIC Science & Technology

1987-06-01

size to develop a composite with 61% fine grains mixed with 39% coarse grains by volume. The stack was placed inside a stainless steel vacuum bag and...alloys, considerable interest exists for superplastic forming of the alloys. However, the first order priority is to consolidate a void- free and...1o- 0 1 5 " 20 25 Oelto K. bPa (sqrt(m)) Fig. 3.3-38 Secondary cracking vs AK, forged material, as-forged, heat treatment No. 2, including load shed

Influence of Pulsed Current on Superplasticity of Fine Grained 1420 Al-Li Alloy

NASA Astrophysics Data System (ADS)

Zhang, Yanling; Hou, Hongliang; Bi, Jing; Wang, Yaoqi

2018-01-01

The effects of an externally applied electropulse on the superplastic deformation behavior and microstructure of 1420 Al-Li alloy were studied. The flow stress of superplastic deformation was reduced by the high-density electropulse while the elongation was increased. The optimal electrical parameters for superplastic deformation were 192A/mm2 of current density, 150Hz of frequency and 30s of duration at 480°C and 0.001s-1. The elongation raised by 68% compared to that without electropulse. Furthermore, the grain was refined and the average grain size was reduced after superplastic deformation with the optimal electropulse. It is noted that the electropulse promoted the recrystallization and restrained the grain growth.

Ti6Al4V Superplastic Forming for the Production of an Aircraft Part

NASA Astrophysics Data System (ADS)

Filice, L.; Gagliardi, F.; Lazzaro, S.; Rosa, R.

2011-05-01

Titanium and its alloys have grown their importance in the automotive and aerospace industries becoming strategic materials; this is due to their mechanical properties that, perfectly, meet the needs of the above said industrial field. For example, they are characterized by a high strength vs. weight ratio that is directly related to fuel saving impacting on both economic and environmental aspects. A weakness point of these materials is linked to their workability that entails significant manufacturing costs. Taking into account these issues, it is easy to understand the reasons for the development of net shape technologies, like hot forming (HF) or superplastic forming (SPF) in order to reduce the price of titanium components. In the work here introduced, a cockpit section, known as "Pocket Support", was produced through SPF. More in detail, the influence that the strain rate can have on the quality of the final part was highlighted; for this reason, two different pressure-time curves were tested monitoring the accuracy and wall thinning of the realized parts. The experimental campaign was carried out using an ACB superplastic forming press located in the Somma Vesuviana DEMA plant. The dimension of the obtained components were checked through the structural light technique (Gray Code-Phase Shifting); in particular, a cloud of points was obtained and, subsequently, used to rebuild the actual surface of the Pocket Support. In this way, a comparison between the CAD model and the real part was possible. Moreover, the thickness distribution along a critical section was analyzed by means of a coordinate measuring machine.

Incremental Feeding High-Pressure Sliding for Grain Refinement of Large-Scale Sheets: Application to Inconel 718

NASA Astrophysics Data System (ADS)

Takizawa, Yoichi; Sumikawa, Kosei; Watanabe, Kyohei; Masuda, Takahiro; Yumoto, Manabu; Kanai, Yuta; Otagiri, Yoshiharu; Horita, Zenji

2018-03-01

This study updates a process of high-pressure sliding (HPS) recently developed as a severe plastic deformation process under high pressure for grain refinement of sheet samples. The updated version, which we call the incremental feeding HPS (IF-HPS), consists of sliding for SPD and feeding for upsizing the SPD-processed area so that, without increasing the capacity of processing facility, it is possible to cover a much larger area with an SPD-processed ultrafine-grained structure with a grain size of 120 nm. For the IF-HPS processing, anvils with flat surfaces but without grooves are used in an unconstrained condition, and the feeding distance is set equal to the deformed width. A Ni-based superalloy (Inconel 718) is processed by the IF-HPS under 4 GPa at room temperature, and it is possible to obtain an SPD-processed sheet with dimensions of approximately 100 × 100 × 1 mm3. Strain distribution and evolution were examined by hardness measurement and simulation using a finite element method. Tensile tests were conducted using tensile specimens extracted from the IF-HPS-processed sheet. Advent of high strain rate superplasticity with the total elongation of more than 400 pct was confirmed by pulling the tensile specimens with an initial strain rate of 2.0 × 10-2 s-1 at a temperature as low as 1073 K. The formability of the IF-HPS-processed sheet was confirmed by successful cup forming. It was also confirmed that the restoration after the superplastic deformation was feasible by subjecting to conventional heat treatment used for Inconel 718.

Application of superplastically formed and diffusion bonded aluminum to a laminar flow control leading edge

NASA Technical Reports Server (NTRS)

Goodyear, M. D.

1987-01-01

NASA sponsored the Aircraft Energy Efficiency (ACEE) program in 1976 to develop technologies to improve fuel efficiency. Laminar flow control was one such technology. Two approaches for achieving laminar flow were designed and manufactured under NASA sponsored programs: the perforated skin concept used at McDonnell Douglas and the slotted design used at Lockheed-Georgia. Both achieved laminar flow, with the slotted design to a lesser degree (JetStar flight test program). The latter design had several fabrication problems concerning springback and adhesive flow clogging the air flow passages. The Lockheed-Georgia Company accomplishments is documented in designing and fabricating a small section of a leading edge article addressing a simpler fabrication method to overcome the previous program's manufacturing problems, i.e., design and fabrication using advanced technologies such as diffusion bonding of aluminum, which has not been used on aerospace structures to date, and the superplastic forming of aluminum.

Determination of optimum parameters of the technological process for plates forming from V95 and V-1461 alloys in creep applied in aircrafts constructed by “Sukhoi design bureau”

NASA Astrophysics Data System (ADS)

Raevskaya, G. A.; Zakharchenko, K.; Larichkin, A.

2017-10-01

The research is devoted to the scientific justification of metal processing by pressure with the help of thick monolithic plates forming (thickness 40 mm) from the V95 (analog 7475) (Al-Zn-Mg-Cu) and V-1461 (analog 2099) (Al-Cu-Li-Zn) alloys in creep and close-to-superplasticity. Optimum parameters of the technological process of plate forming are described. The effect of temperature on the magnitude of mechanical stresses (relaxation) during the tests of materials on pure bending is experimentally determined. Forming of thick plates (40 mm) on the UFP-1M unit, and the control of the obtained surface, in comparison with the given electronic model, made it possible to experimentally determine the time and number of forming stages. Mechanical properties of the material after the technological process and heat treatment are preliminary evaluated. The efficiency of using the obtained parameters of the technological process and treatment of metals by pressure in such methods in general is shown.

Simulation for analysis and control of superplastic forming. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zacharia, T.; Aramayo, G.A.; Simunovic, S.

1996-08-01

A joint study was conducted by Oak Ridge National Laboratory (ORNL) and the Pacific Northwest Laboratory (PNL) for the U.S. Department of Energy-Lightweight Materials (DOE-LWM) Program. the purpose of the study was to assess and benchmark the current modeling capabilities with respect to accuracy of predictions and simulation time. Two modeling capabilities with respect to accuracy of predictions and simulation time. Two simulation platforms were considered in this study, which included the LS-DYNA3D code installed on ORNL`s high- performance computers and the finite element code MARC used at PNL. both ORNL and PNL performed superplastic forming (SPF) analysis on amore » standard butter-tray geometry, which was defined by PNL, to better understand the capabilities of the respective models. The specific geometry was selected and formed at PNL, and the experimental results, such as forming time and thickness at specific locations, were provided for comparisons with numerical predictions. Furthermore, comparisons between the ORNL simulation results, using elasto-plastic analysis, and PNL`s results, using rigid-plastic flow analysis, were performed.« less

AFWAL FY80 Technical Accomplishments Report.

DTIC Science & Technology

1981-12-01

through cooperative effort of the Materials and Certain compositions in the titanium aluminide Propulsion Laboratories. In addition to an extensive system...Bonded Structures Technology Transitioned .................................................. 43 Superplastically Formed and Diffusion Bonded Titanium ...Technology ................................................................................................. 75 First RSR Radial Wafer Blade Engine Test

Low Temperature Superplasticity of Ti-6Al-4V Processed by Warm Multidirectional Forging (Preprint)

DTIC Science & Technology

2012-07-01

microstructure in the two-phase titanium alloy Ti- 6Al - 4V . A microstructure with a grain size of 135 nm was attained, enabling low-temperature...the / titanium alloy Ti- 6Al - 4V [3]. The great interest in microstructure refinement is associated with significantly reduced superplastic (SP...consisted of the / titanium alloy Ti- 6Al - 4V with a nominal composition (in weight pct.) of 6.3 Al, 4.1 V, 0.18 Fe, 0.03 Si, 0.02 Zr, 0.01 C, 0.18 O, 0.01 N

A Microstructure-Based Constitutive Model for Superplastic Forming

NASA Astrophysics Data System (ADS)

Jafari Nedoushan, Reza; Farzin, Mahmoud; Mashayekhi, Mohammad; Banabic, Dorel

2012-11-01

A constitutive model is proposed for simulations of hot metal forming processes. This model is constructed based on dominant mechanisms that take part in hot forming and includes intergranular deformation, grain boundary sliding, and grain boundary diffusion. A Taylor type polycrystalline model is used to predict intergranular deformation. Previous works on grain boundary sliding and grain boundary diffusion are extended to drive three-dimensional macro stress-strain rate relationships for each mechanism. In these relationships, the effect of grain size is also taken into account. The proposed model is first used to simulate step strain-rate tests and the results are compared with experimental data. It is shown that the model can be used to predict flow stresses for various grain sizes and strain rates. The yield locus is then predicted for multiaxial stress states, and it is observed that it is very close to the von Mises yield criterion. It is also shown that the proposed model can be directly used to simulate hot forming processes. Bulge forming process and gas pressure tray forming are simulated, and the results are compared with experimental data.

Superplastic behavior of two ultrahigh boron steels

NASA Astrophysics Data System (ADS)

Jiménez, J. A.; González-Doncel, G.; Acosta, P.; Ruano, O. A.

1994-06-01

The high-temperature deformation behavior of two ultrahigh boron steels containing 2.2 pct and 4.9 pct B was investigated. Both alloys were processed via powder metallurgy involving gas atomization and hot isostatic pressing (hipping) at various temperatures. After hipping at 700 °C, the Fe-2.2 pct B alloy showed a fine microstructure consisting of l- µm grains and small elongated borides (less than 1 µm) . At 1100 °C, a coarser microstructure with rounded borides was formed. This alloy was superplastic at 850 °C with stress exponents of about two and tensile elongations as high as 435 pct. The microstructure of the Fe-4.9 pct B alloy was similar to that of the Fe-2.2 pct B alloy showing, in addition, coarse borides. This alloy also showed low stress exponent values but lacked high tensile elongation (less than 65 pct), which was attributed to the presence of stress accumulation at the interface between the matrix and the large borides. A change in the activation energy value at the α-γ transformation temperature was seen in the Fe-2.2 pct B alloy. The plastic flow data were in agreement with grain boundary sliding and slip creep models.

Deformation behaviour of a new magnesium ternary alloy

NASA Astrophysics Data System (ADS)

Guglielmi, P.; Kaya, A. Arslan; Sorgente, D.; Palumbo, G.

2018-05-01

Magnesium based alloys are yet to fill a greater niche especially in the automotive and aeronautical industry. In fact, such alloys have a big weight saving potential, together with good damping characteristics. However, nowadays about 90% of Magnesium products are produced by casting, mainly using two alloy systems, namely Mg-Al-Zn (AZ91D) and Mg-Al (AM50, AM60). Now the emphasis, especially after having achieved considerable success in creep resistance and understanding of the deformation behaviour of Magnesium, has been shifted towards wrought alloys; AZ31, in this case, is the most popular. In this work a multi-element Magnesium alloy, developed to improve the deformation capacity of such a lightweight material, has been investigated and compared to a commercial AZ31B. The possibility of adopting such a multi-element Magnesium alloy for manufacturing components via unconventional sheet forming (such as superplastic forming, warm hydroforming, incremental forming) has been proved in the present work focusing the attention on the superplastic field. Free inflation tests were thus conducted at 450°C setting constant pressure to investigate the superplastic behaviour (in terms of dome height and strain rate sensitivity index) of both the multi-element Magnesium alloy (Mg-2Zn-Ce) and the commercial one (AZ31B). To enhance information on the thickness distribution and investigate the microstructure evolution, metallographic analyses on the samples used to carry out free inflation tests were also performed. The developed ternary alloy manifested quite a good deformation behaviour (high strain rate sensitivity index), even being tested in the as cast condition; in addition a limited grain coarsening was observed in the specimens after deformation.

The deformation behavior and microstructure evolution of duplex Mg-9Li-1Al alloy during superplasticity tensile testing

NASA Astrophysics Data System (ADS)

Liu, Meiduo; Zheng, Haipeng; Zhang, Tianlong; Wu, Ruizhi

2017-12-01

The superplastic mechanical properties and microstructure evolution of the duplex Mg-9Li-1Al alloy were investigated. The tensile testing results show that, the elongation of the as-extruded Mg-9Li-1Al alloy reaches 510% at 573 K with a strain rate of 2×10-4 s-1. During the deformation process, the strips of α phase break into equiaxed structure. This phenomenon can be attributed to a particular dynamic recrystallization, which suggests that the β phase can recrystallize in the α phase due to the small misfit degree between α phase and β phase.

Investigation by Differential Scanning Calorimetry of Microstructure in a Superplastic Al-Mg-Zr Alloy.

DTIC Science & Technology

1987-06-01

cold-rolled zinc-copper-aluminum eutectic alloy exhibited this superplastic response. Superplasticity was initially viewed as a curious observation...limited to eutectic alloys when tested under the correct laboratory conditions. However, in 1962 Underwood [Ref. 23 reviewed Soviet work; this review...formation of a very fine dispersoid, ZrAI3. This dispersoid results in grain refinement, raises the recrystallization temperature (Ref. 7:p. 414] and gives

Roll-to-Roll Nanoforming of Metals Using Laser-Induced Superplasticity.

PubMed

Goswami, Debkalpa; Munera, Juan C; Pal, Aniket; Sadri, Behnam; Scarpetti, Caio Lui P G; Martinez, Ramses V

2018-05-24

This Letter describes a low-cost, scalable nanomanufacturing process that enables the continuous forming of thin metallic layers with nanoscale accuracy using roll-to-roll, laser-induced superplasticity (R2RLIS). R2RLIS uses a laser shock to induce the ultrahigh-strain-rate deformation of metallic films at room temperature into low-cost polymeric nanomolds, independently of the original grain size of the metal. This simple and inexpensive nanoforming method does not require access to cleanrooms and associated facilities, and can be easily implemented on conventional CO 2 lasers, enabling laser systems commonly used for rapid prototyping or industrial cutting and engraving to fabricate uniform and three-dimensional crystalline metallic nanostructures over large areas. Tuning the laser power during the R2RLIS process enables the control of the aspect ratio and the mechanical and optical properties of the fabricated nanostructures. This roll-to-roll technique successfully fabricates mechanically strengthened gold plasmonic nanostructures with aspect ratios as high as 5 that exhibit high oxidation resistance and strong optical field enhancements. The CO 2 laser used in R2RLIS can also integrate the fabricated nanostructures on transparent flexible substrates with robust interfacial contact. The ability to fabricate ultrasmooth metallic nanostructures using roll-to-roll manufacturing enables the large scale production, at a relatively low-cost, of flexible plasmonic devices toward emerging applications.

Abnormal Grain Growth Suppression in Aluminum Alloys

NASA Technical Reports Server (NTRS)

Hales, Stephen J. (Inventor); Claytor, Harold Dale (Inventor); Alexa, Joel A. (Inventor)

2015-01-01

The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment ("IAT") after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

Superplastic Aluminum Evaluation

DTIC Science & Technology

1981-06-01

Gold coated. 450 Lilt to electron beam ...................... ............... 111 16 Scanning electron micrograph of a cross section through a cavity... Gold coated. 450 tilt to electron beam ............. ...... .. ... 113 17 Typical EDAX spectra from (a) dark, angular, loose particles ((Fe,Cr)3SiAll...with atmospheric water vapor to form aluminum oxide and hydrogen. The hydrogen (already in monoatomic form) is very rapidly dissolved by the liquid

Comparison of microstructure of superplastically deformed synthetic materials and ultramylonite: Coalescence of secondary mineral grains via grain boundary sliding

NASA Astrophysics Data System (ADS)

Hiraga, T.; Miyazaki, T.; Tasaka, M.; Yoshida, H.

2011-12-01

Using very fine-grained aggregates of forsterite containing ~10vol% secondary mineral phase such as periclase and enstatite, we have been able to demonstrate their superplascity, that is, achievement of more than a few 100 % tensile strain (Hiraga et al. 2010). Superplastic deformation is commonly considered to proceed via grain boundary sliding (GBS) which results in grain switching in the samples. Hiraga et al. (2010) succeeded in detecting the operation of GBS from observing the coalescence of grains of secondary phase in superplastically deformed samples. The secondary phase pins the motion of grain boundaries of the primary phase; however, the reduction of the number of the grains of secondary phase due to their coalescence allows grain growth of the primary phase. We analyzed the relationships between grain size of the primary and secondary phases, between strain and grain size, and between strain and the number of coalesced grains in the superplastically deformed samples. The results supports participation of all the grains of the primary phase in grain switching process indicating that the grain boundary sliding accommodates almost entire strain during the deformation. Mechanical properties of these materials such as their stress and grain size exponents of 1-2 do not conflict this conclusion. We applied the relationships obtained from analyzing superplastic materials to the microstructure of the natural samples, which has been considered to have deformed via grain boundary sliding, that is, ultramylonite. The microstructure of greenschist-grade ultramylonite reported by Fliervoet et al. (1997) was analyzed. Distributions of the mineral phases (i.e., quartz, plagioclase, K-feldspar and biotite) show distinct coalescence of the same mineral phases in the direction almost perpendicular to the foliation of the rock. The number of coalesced grains indicates that the strain that rock experienced is > 2. [reference] Hiraga et al. (2010) Nature 468, 1091-1094; Fliervoet et al. (1997) Journal of Structural Geology 19, 1495-1520

Effect of Various SPD Techniques on Structure and Superplastic Deformation of Two Phase MgLiAl Alloy

NASA Astrophysics Data System (ADS)

Dutkiewicz, Jan; Bobrowski, Piotr; Rusz, Stanislav; Hilser, Ondrej; Tański, Tomasz A.; Borek, Wojciech; Łagoda, Marek; Ostachowski, Paweł; Pałka, Paweł; Boczkal, Grzegorz; Kuc, Dariusz; Mikuszewski, Tomasz

2018-03-01

MgLiAl alloy containing 9 wt% Li and 1.5% Al composed of hexagonal α and bcc β phases was cast under protecting atmosphere and hot extruded. Various methods of severe plastic deformation were applied to study their effect on structure and grain refinement. Rods were subjected to 1-3 passes of Twist Channel Angular Pressing TCAP (with helical component), cyclic compression to total strain ɛ = 5 using MAXStrain Gleeble equipment, both performed at temperature interval 160-200 °C and, as third SPD method, KOBO type extrusion at RT. The TCAP pass resulted in grain refinement of α phase from 30 μm down to about 2 μm and that of β phase from 12 to 5 μm. Maxstrain cycling 10 × up to ɛ = 5 led to much finer grain size of 300 nm. KOBO method performed at RT caused average grain size refinement of α and β phases down to about 1 μm. Hardness of alloy decreased slightly with increasing number of TCAP passes due to increase of small void density. It was higher after MAXStrain cycling and after KOBO extrusion. TEM studies after TCAP passes showed higher dislocation density in the β region than in the α phase. Crystallographic relationship (001) α|| (110) β indicated parallel positioning of slip planes of both phases. Electron diffraction technique confirmed increase of grain misorientation with number of TCAP passes. Stress/strain curves recorded at temperature 200 °C showed superplastic forming after 1st and 3rd TCAP passes with better superplastic properties due to higher elongation with increasing number of passes. Values of strain rate sensitivity coefficient m were calculated at 0.29 after 3rd TCAP pass for strain rate range 10-5 to 5 × 10-3 s-1. Deformation by MAXStrain cycling caused much more effective grain refinement with fine microtwins in α phase. Superplastic deformation was also observed in alloy deformed by KOBO method, however the value of m = 0.21 was obtained at lower temperature of deformation equal to 160 °C and deformation rate in the range 10-5 to 5 × 10-3. Tensile samples deformed superplastically showed grain growth and void formation caused by grain boundary slip. Summarizing, all methods applied resulted in sufficient grain refinement to obtain the effect of superplastic deformation for alloys of two phase α + β structure.

Review of European Powder Metallurgy of Superalloys.

DTIC Science & Technology

1979-12-01

after suitable slag skiimming, atomization occurs through a ceramic nozzle. Powder falls through the atomizing tower and is collected in a water...shaped container for HIP. Superplastic bag forming is also being investigated( 2 7 ) , but few details are available. Glass cans have also been used for

Superplastic forming and diffusion bonding of rapidly solidified, dispersion strengthened aluminum alloys for elevated temperature structural applications

NASA Technical Reports Server (NTRS)

Ting, E. Y.; Kennedy, J. R.

1989-01-01

Rapidly solidified alloys, based upon the Al-Fe-V-Si system and designed for elevated temperature applications, were evaluated for superplasticity and diffusion bonding behavior. Alloys with 8, 16, 27, and 36 volume percent silicide dispersoids were produced; dispersoid condition was varied by rolling at 300, 400, and 500 C (572, 752, and 932 F). Superplastic behavior was evaluated at strain rates from 1 x 10(exp -6)/s to 8.5/s at elevated temperatures. The results indicate that there was a significant increase in elongation at higher strain rates and at temperatures above 600 C (1112 F). However, the exposure of the alloys to temperatures greater than 600 C (1112 F) resulted in the coarsening of the strengthening dispersoid and the degradation of mechanical properties. Diffusion bonding was possible using low gas pressure at temperatures greater than 600 C (1112 F) which also resulted in degraded properties. The bonding of Al-Fe-V-Si alloys to 7475 aluminum alloy was performed at 516 C (960 F) without significant degradation in microstructure. Bond strengths equal to 90 percent that of the base metal shear strength were achieved. The mechanical properties and microstructural characteristics of the alloys were investigated.

SPF/DB titanium concepts for structural efficiency foi HC

NASA Technical Reports Server (NTRS)

Wilson, V. E.

1982-01-01

Illustrations for a presentation on superplastic forming/diffusion bonding titanium design concepts are presented. Sandwich skin panels with hat section, semicircular corrugation, sine wave, and truss cores are shown. The fabrication of wing panels is illustrated, and applications to the design of advanced variable sweep bombers summarized.

Effect of temperature and grain size on the dominant diffusion process for superplastic flow in an AZ61 magnesium alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, H.; Mukai, T.; Kohzu, M.

1999-10-26

The effect of temperature and grain size on superplastic flow was investigated using a relatively coarse-grained ({approximately}20 {micro}m) Mg-Al-Zn alloy for the inclusive understanding of the dominant diffusion process. Tensile tests revealed that the strain rate was inversely proportional to the square of the grain size and to the second power of stress. The activation energy was close to that for grain boundary diffusion at 523--573 K, and was close to that for lattice diffusion at 598--673 K. From the analysis of the stress exponent, the grain size exponent and activation energy, it was suggested that the dominant diffusion processmore » was influenced by temperature and grain size. It was demonstrated that the notion of effective diffusivity explained the experimental results.« less

New trends in metal forming in the USA

NASA Astrophysics Data System (ADS)

1982-05-01

The use of lasers in sheet metal stamping, hydraulic presses, cold pressing, and deformation of titanium alloy to produce components which do not require subsequent machining are discussed. Superplastic deformation techniques could lead to cost savings of 90% in the aerospace industry. Precision forging and welding technologies can considerably reduce raw material costs, but investment costs are high.

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, M.J.; Goldberg, A.; Sherby, O.D.; Landingham, R.L.

1995-08-29

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50 C above the A{sub 1} transformation temperature, soaking the steel above the A{sub 1} temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature. 9 figs.

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, Michael J.; Goldberg, Alfred; Sherby, Oleg D.; Landingham, Richard L.

1995-01-01

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50.degree. C. above the A.sub.1 transformation temperature, soaking the steel above the A.sub.1 temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature.

Superplastic forging nitride ceramics

DOEpatents

Panda, P.C.; Seydel, E.R.; Raj, R.

1988-03-22

A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

Deformation of superplastic alloys at relatively low strain rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grivas, D.

1978-02-01

The superplastic and sub-superplastic creep properties of Pb-Sn eutectic and Al-Zn eutectoid alloys were studied. Various thermomechanical treatments we tested to check the possibilities of whether the subsuperplastic deformation mechanism is affected by these treatments. All thermomechanical histories were found to reveal the same stress exponent, which is believed to be indicative of the predominant mechanism. The mechanical data in the low stress region lead us to suggest that dislocation glide is the predominant mechanism in this region. At higher stresses extensive grain boundary sliding takes place and the dislocation movement is directed to relieve the stress concentration developed bymore » the grain movement.« less

Superplastic forging nitride ceramics

DOEpatents

Panda, Prakash C.; Seydel, Edgar R.; Raj, Rishi

1988-03-22

The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forging This invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.

Superplastic Deformation Mechanisms of Superfine/Nanocrystalline Duplex PM-TiAl-Based Alloy

PubMed Central

Gong, Xuebo; Duan, Zhenxin; Pei, Wen; Chen, Hua

2017-01-01

In this paper, the equiaxed superfine/nanocrystalline duplex PM-TiAl-based alloy with (γ + α2) microstructure, Ti-45Al-5Nb (at %), has been synthesized by high-energy ball milling and vacuum hot pressing sintering. Superplastic deformation behavior has been investigated at 1000 °C and 1050 °C with strain rates from 5 × 10−5 s−1 to 1 × 10−3 s−1. The effects of deformation on the microstructure and mechanical behaviors of high Nb containing TiAl alloy have been characterized and analyzed. The results showed that, the ultimate tensile strength of the alloy was 58.7 MPa at 1000 °C and 10.5 MPa at 1050 °C with a strain rate of 5 × 10−5 s−1, while the elongation was 121% and 233%, respectively. The alloy exhibited superplastic elongation at 1000 and 1050 °C with an exponent (m) of 0.48 and 0.45. The main softening mechanism was dynamic recrystallization of γ grains; the dislocation slip and γ/γ interface twinning were responsible for superplastic deformation. The orientation relationship of γ/γ interface twinning obeyed the classical one: (001)γ//(110)γ. PMID:28925971

Superplastic Deformation Mechanisms of Superfine/Nanocrystalline Duplex PM-TiAl-Based Alloy.

PubMed

Gong, Xuebo; Duan, Zhenxin; Pei, Wen; Chen, Hua

2017-09-19

In this paper, the equiaxed superfine/nanocrystalline duplex PM-TiAl-based alloy with (γ + α₂) microstructure, Ti-45Al-5Nb (at %), has been synthesized by high-energy ball milling and vacuum hot pressing sintering. Superplastic deformation behavior has been investigated at 1000 °C and 1050 °C with strain rates from 5 × 10 -5 s -1 to 1 × 10 -3 s -1 . The effects of deformation on the microstructure and mechanical behaviors of high Nb containing TiAl alloy have been characterized and analyzed. The results showed that, the ultimate tensile strength of the alloy was 58.7 MPa at 1000 °C and 10.5 MPa at 1050 °C with a strain rate of 5 × 10 -5 s -1 , while the elongation was 121% and 233%, respectively. The alloy exhibited superplastic elongation at 1000 and 1050 °C with an exponent (m) of 0.48 and 0.45. The main softening mechanism was dynamic recrystallization of γ grains; the dislocation slip and γ/γ interface twinning were responsible for superplastic deformation. The orientation relationship of γ/γ interface twinning obeyed the classical one: (001) γ //(110) γ .

Thermal Microstructural Stability of AZ31 Magnesium after Severe Plastic Deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, John P.; Askari, Hesam A.; Hovanski, Yuri

2015-03-01

Both equal channel angular pressing and friction stir processing have the ability to refine the grain size of twin roll cast AZ31 magnesium and potentially improve its superplastic properties. This work used isochronal and isothermal heat treatments to investigate the microstructural stability of twin roll cast, equal channel angular pressed and friction stir processed AZ31 magnesium. For both heat treatment conditions, it was found that the twin roll casted and equal channel angular pressed materials were more stable than the friction stir processed material. Calculations of the grain growth kinetics showed that severe plastic deformation processing decreased the activation energymore » for grain boundary motion with the equal channel angular pressed material having the greatest Q value of the severely plastically deformed materials and that increasing the tool travel speed of the friction stir processed material improved microstructural stability. The Hollomon-Jaffe parameter was found to be an accurate means of identifying the annealing conditions that will result in substantial grain growth and loss of potential superplastic properties in the severely plastically deformed materials. In addition, Humphreys’s model of cellular microstructural stability accurately predicted the relative microstructural stability of the severely plastically deformed materials and with some modification, closely predicted the maximum grain size ratio achieved by the severely plastically deformed materials.« less

Future requirements for advanced materials

NASA Technical Reports Server (NTRS)

Olstad, W. B.

1980-01-01

Recent advances and future trends in aerospace materials technology are reviewed with reference to metal alloys, high-temperature composites and adhesives, tungsten fiber-reinforced superalloys, hybrid materials, ceramics, new ablative materials, such as carbon-carbon composite and silica tiles used in the Shuttle Orbiter. The technologies of powder metallurgy coupled with hot isostatic pressing, near net forging, complex large shape casting, chopped fiber molding, superplastic forming, and computer-aided design and manufacture are emphasized.

Flame-resistant Ca-containing AZ31 magnesium alloy sheets with good mechanical properties fabricated by a combination of strip casting and high-ratio differential speed rolling methods

NASA Astrophysics Data System (ADS)

Kim, Y. H.; Kim, W. J.

2015-03-01

This study reported that a combination of strip casting and high-ratio differential speed rolling (HRDSR) can produce flame-resistant Mg alloy sheets (0.7 wt%Ca-AZ31: 0.7Ca-AZ31) with good room-temperature mechanical properties and high-temperature formability. HRDSR effectively refined the coarse microstructure of the strip-casting processed 0.7Ca-AZ31 alloy. As the result, the (true) grain size was reduced to as small as 2.7 μm and the (Mg, Al)2Ca phase was broken up to fine particles with an average sizes of 0.5 μm. Due to the advantage of having such a highly refined microstructure, the HRDSR-processed 0.7Ca-AZ31 alloy sheet exhibited a high yield stress over 300 MPa and good superplasticity at elevated temperatures. The deformation mechanism of the fine-grained 0.7Ca-AZ31 alloy in the superplastic regime was identified to be grainboundary-diffusion or lattice-diffusion controlled grain boundary sliding.

Analysis of the Transition in Deformation Mechanisms in Superplastic 5083 Aluminum Alloys by Orientation Imaging Microscopy

DTIC Science & Technology

2001-09-01

Analysis of the Transition in Deformation Mechanisms in Superplastic 5083 Aluminum Alloys by Orientation Imaging Microscopy 6. AUTHOR( S ) Harrell...James W. 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Postgraduate School Monterey, CA 93943-5000 8. PERFORMING...ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME( S ) AND ADDRESS(ES) General Motors Corp., Research and Development Center

Connections: Superplasticity, Damascus Steels, Laminated Steels, and Carbon Dating

NASA Astrophysics Data System (ADS)

Wadsworth, Jeffrey

2016-12-01

In this paper, a description is given of the connections that evolved from the initial development of a family of superplastic plain carbon steels that came to be known as Ultra-High Carbon Steels (UHCS). It was observed that their very high carbon contents were similar, if not identical, to those of Damascus steels. There followed a series of attempts to rediscover how the famous patterns found on Damascus steels blades were formed. At the same time, in order to improve the toughness at room temperature of the newly-developed UHCS, laminated composites were made of alternating layers of UHCS and mild steel (and subsequently other steels and other metals). This led to a study of ancient laminated composites, the motives for their manufacture, and the plausibility of some of the claims relating to the number of layers in the final blades. One apparently ancient laminated composite, recovered in 1837 from the great pyramid of Giza which was constructed in about 2750 B.C., stimulated a carbon dating study of ancient steels. The modern interest in "Bladesmithing" has connections back to many of these ancient weapons.

Transition from poor ductility to room-temperature superplasticity in a nanostructured aluminum alloy.

PubMed

Edalati, Kaveh; Horita, Zenji; Valiev, Ruslan Z

2018-04-30

Recent developments of nanostructured materials with grain sizes in the nanometer to submicrometer range have provided ground for numerous functional properties and new applications. However, in terms of mechanical properties, bulk nanostructured materials typically show poor ductility despite their high strength, which limits their use for structural applications. The present article shows that the poor ductility of nanostructured alloys can be changed to room-temperature superplastisity by a transition in the deformation mechanism from dislocation activity to grain-boundary sliding. We report the first observation of room-temperature superplasticity (over 400% tensile elongations) in a nanostructured Al alloy by enhanced grain-boundary sliding. The room-temperature grain-boundary sliding and superplasticity was realized by engineering the Zn segregation along the Al/Al boundaries through severe plastic deformation. This work introduces a new boundary-based strategy to improve the mechanical properties of nanostructured materials for structural applications, where high deformability is a requirement.

Mechanistic Studies of Superplasticity of Structural Ceramics

DTIC Science & Technology

1992-02-01

green compact, with a higher density and and most of Ine heavier transition-metal fewer defects and agglomerates, has a cations of the third row, is very...between 60% to 65% of the theoretical defects is merely one which mediates the above solid "elec- density. Samples of 2Y-TZP and other TZPs were prepared...trolyte," although any tendency toward binding between similarly, except for a smaller dopant concentration ot 0.6% point defects and dopants to form

Finite Element Modeling, Simulation, Tools, and Capabilities at Superform

NASA Astrophysics Data System (ADS)

Raman, Hari; Barnes, A. J.

2010-06-01

Over the past thirty years Superform has been a pioneer in the SPF arena, having developed a keen understanding of the process and a range of unique forming techniques to meet varying market needs. Superform’s high-profile list of customers includes Boeing, Airbus, Aston Martin, Ford, and Rolls Royce. One of the more recent additions to Superform’s technical know-how is finite element modeling and simulation. Finite element modeling is a powerful numerical technique which when applied to SPF provides a host of benefits including accurate prediction of strain levels in a part, presence of wrinkles and predicting pressure cycles optimized for time and part thickness. This paper outlines a brief history of finite element modeling applied to SPF and then reviews some of the modeling tools and techniques that Superform have applied and continue to do so to successfully superplastically form complex-shaped parts. The advantages of employing modeling at the design stage are discussed and illustrated with real-world examples.

Innovative forming and fabrication technologies : new opportunities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, B.; Hryn, J.; Energy Systems

2008-01-31

The advent of light metal alloys and advanced materials (polymer, composites, etc.) have brought the possibility of achieving important energy reductions into the full life cycle of these materials, especially in transportation applications. 1 These materials have gained acceptance in the aerospace industry but use of light metal alloys needs to gain wider acceptance in other commercial transportation areas. Among the main reasons for the relatively low use of these materials are the lack of manufacturability, insufficient mechanical properties, and increased material costs due to processing inefficiencies. Considering the enormous potential energy savings associated with the use of light metalmore » alloys and advanced materials in transportation, there is a need to identify R&D opportunities in the fields of materials fabrication and forming aimed at developing materials with high specific mechanical properties combined with energy efficient processes and good manufacturability. This report presents a literature review of the most recent developments in the areas of fabrication and metal forming focusing principally on aluminum alloys. In the first section of the document, the different sheet manufacturing technologies including direct chill (DC) casting and rolling, spray forming, spray rolling, thin slab, and strip casting are reviewed. The second section of the document presents recent research on advanced forming processes. The various forming processes reviewed are: superplastic forming, electromagnetic forming, age forming, warm forming, hydroforming, and incremental forming. Optimization of conventional forming processes is also discussed. Potentially interesting light metal alloys for high structural efficiency including aluminum-scandium, aluminum-lithium, magnesium, titanium, and amorphous metal alloys are also reviewed. This section concludes with a discussion on alloy development for manufacturability. The third section of the document reviews the latest developments in fiber-reinforced composite materials. Emerging curing processes are presented along with a discussion on the possible developments in biocomposite materials. The fourth section presents recent developments in the fabrication of bulk nanomaterials and nanoparticles reinforced materials. Advanced joining technologies are presented in the fifth section. Future research is proposed in the last section.« less

Superplasticity - A Fundamental Investigation on Deformation Mechanism and Cavitation Phenomena.

DTIC Science & Technology

1988-02-15

NI-MODIFIED SUPERPLASTIC Ti- 6Al - 4V ALLOY, B. Hidalgo-Prada and A.K. Mukherjee, Proc. of Intnl. Conf. of Strength of Metals and AlloyS-7, Montreal...features, e.g., initial porosity (15 to 500 pm diam.), stringers (of Fe-rich particles, 5-30 pm diam.), and small (0.3-3 pm) copper- rich particles...500% or greater, porosity between grains was observed. Some grains as well as grain clusters are visible in Fig. 6. The grain clusters are believed to

Study of Cavitation and Failure Mechanisms of a Superplastic 5083 Aluminum Alloy

DTIC Science & Technology

2003-09-01

Failure Mechanisms of a Superplastic 5083 Aluminum Alloy 6. AUTHOR( S ) Boydon, Juanito F. 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME( S ) AND...NAME( S ) AND ADDRESS(ES) General Motors Corp., Research and Development Center, Warren, MI (Dr. Paul E. Krajewski, Technical Program...of 973931(A3), deformed gauge area 1- region 1. Sample was pulled under uniaxial tension at 450 °C at a strain rate of 3x10-4 s -1 and elongated to

Effect of anisotropy on mechanical properties of Ti-6Al-4V in superplastic region

NASA Astrophysics Data System (ADS)

Wahed, MA; Gupta, AK; Singh, SK; Kotkunde, N.

2018-04-01

This paper presents an experimental investigation on the flow stress behaviour of Ti-6Al-4V alloy at elevated temperatures and very low strain rate. Though Ti-6Al-4V alloy is very hard to deform at room temperature, having only about 16 % elongation, it exhibits super-plasticity at elevated temperatures. To investigate this, the tensile tests were conducted from 700°C to 900°C temperatures at an interval of 50°C and at a very low strain rate 0.0001/s along three different directions: rolling direction, 45° to rolling direction and transverse direction. The experimental study shows more than 50% elongation in all the cases and particularly more than 250% elongation at 0.0001 / s strain rate and at 750°C to 900°C temperature in all directions, which is an indication of super-plasticity in the material. This is also corroborated by the microstructural study of the fractured specimens.

High temperature tensile and creep behaviour of low pressure plasma-sprayed Ni-Co-Cr-Al-Y coating alloy

NASA Technical Reports Server (NTRS)

Hebsur, M. G.; Miner, R. V.

1986-01-01

The high temperature tensile and creep behavior of low pressure plasma-sprayed plates of a typical Ni-Co-Cr-Al-Y alloy has been studied. From room temperature to 800 K, the Ni-Co-Cr-Al-Y alloy studied has nearly a constant low ductility and a high strength. At higher temperatures, it becomes weak and highly ductile. At and above 1123 K, the behavior is highly dependent on strain rate and exhibits classic superplastic characteristics with a high ductility at intermediate strain rates and a strain rate sensitivity of about 0.5. At either higher or lower strain rates, the ductility decreases and the strain rate sensitivities are about 0.2. In the superplastic deformation range, the activation energy for creep is 120 + or - 20 kJ/mol, suggesting a diffusion-aided grain boundary sliding mechanism. Outside the superplastic range, the activation energy for creep is calculated to be 290 + or - 20 kJ/mol.

Aircraft gas turbine materials and processes.

PubMed

Kear, B H; Thompson, E R

1980-05-23

Materials and processing innovations that have been incorporated into the manufacture of critical components for high-performance aircraft gas turbine engines are described. The materials of interest are the nickel- and cobalt-base superalloys for turbine and burner sections of the engine, and titanium alloys and composites for compressor and fan sections of the engine. Advanced processing methods considered include directional solidification, hot isostatic pressing, superplastic foring, directional recrystallization, and diffusion brazing. Future trends in gas turbine technology are discussed in terms of materials availability, substitution, and further advances in air-cooled hardware.

Development of near β titanium alloy with high strength and superplastic properties

NASA Astrophysics Data System (ADS)

Naydenkin, E. V.; Ratochka, I. V.; Mishin, I. P.; Lykova, O. N.

2017-12-01

Ultrafine-grained (UFG) structure with an average element size of about 0.25 µm was obtained in a near β titanium alloy under severe plastic deformation by abc pressing. It is shown that the formation of such structure greatly increases the ultimate strength of the alloy compared to its coarse-grained state (up to 1610 MPa). In addition, the UFG alloy features improved superplastic characteristics under tension at temperatures of 973-1073 K: its elongation to failure exceeds 1300% and the flow stress decreases to several MPa.

Thermoplastic deformation of ferromagnetic CoFe-based bulk metallic glasses

NASA Astrophysics Data System (ADS)

Wu, Chenguang; Hu, Renchao; Man, Qikui; Chang, Chuntao; Wang, Xinmin

2017-12-01

The superplastic deformation behavior of the ferromagnetic Co31Fe31Nb8B30 bulk metallic glass (BMG) in the supercooled liquid region was investigated. At a given temperature, the BMG exhibits a Newtonian behavior at low strain rates but a non-Newtonian behavior at high strain rates. The high thermal stability of this glassy alloy system offers an enough processing window to thermoplastic forming (TPF), and the strong processing ability was examined by simple micro-replication experiments. It is demonstrated that the TPF formability on length scales ranging down to nanometers can be achieved in the selected experimental condition. Based on the analysis of deformation behavior, the nearly full density sample (i.e. nearly 100%), was produced from water-atomized glassy powders and consolidated by the hot-pressing technique. The sample exhibits good soft-magnetic and mechanical properties, i.e., low coercive force of 0.43 Oe, high initial permeability of 4100 and high Vickers hardness 1398. These results suggest that the hot-pressing process opens up possibilities for the commercial exploitation of BMGs in engineering applications.

Conference Proceedings of the Meeting of the Structures and Materials Panel of AGARD (67th) on New Light Alloys, Held in Mierlo, Netherlands on 3-5 October 1988

DTIC Science & Technology

1989-08-01

solution heat treatment. Before anodizing, acid (e.g. suilfochromic) etching is preferable to caustic etching. As observed on 8090, the attack doe to the...differences in preferred crystallographic orientation. From the 1111) pole figures in Fig. 19 it is evident that the texture is much more pronounced in the... Ridley , N., "Cavitation and superplasticity", SUPERPLASTICITY, AGARD-LS-154, Aug. 1987, Paper No. 4. 11. Lane, P.L., Gray, J.A., and Smith, C.J.E

Hot deformation behavior of uniform fine-grained GH4720Li alloy based on its processing map

NASA Astrophysics Data System (ADS)

Yu, Qiu-ying; Yao, Zhi-hao; Dong, Jian-xin

2016-01-01

The hot deformation behavior of uniform fine-grained GH4720Li alloy was studied in the temperature range from 1040 to 1130°C and the strain-rate range from 0.005 to 0.5 s-1 using hot compression testing. Processing maps were constructed on the basis of compression data and a dynamic materials model. Considerable flow softening associated with superplasticity was observed at strain rates of 0.01 s-1 or lower. According to the processing map and observations of the microstructure, the uniform fine-grained microstructure remains intact at 1100°C or lower because of easily activated dynamic recrystallization (DRX), whereas obvious grain growth is observed at 1130°C. Metallurgical instabilities in the form of non-uniform microstructures under higher and lower Zener-Hollomon parameters are induced by local plastic flow and primary γ' local faster dissolution, respectively. The optimum processing conditions at all of the investigated strains are proposed as 1090-1130°C with 0.08-0.5 s-1 and 0.005-0.008 s-1 and 1040-1085°C with 0.005-0.06 s-1.

Superplastic Creep of Metal Nanowires From Rate-Dependent Plasticity Transition

DOE PAGES

Tao, Weiwei; Cao, Penghui; Park, Harold S.

2018-04-30

Understanding the time-dependent mechanical behavior of nanomaterials such as nanowires is essential to predict their reliability in nanomechanical devices. This understanding is typically obtained using creep tests, which are the most fundamental loading mechanism by which the time dependent deformation of materials is characterized. However, due to existing challenges facing both experimentalists and theorists, the time dependent mechanical response of nanowires is not well-understood. Here, we use atomistic simulations that can access experimental time scales to examine the creep of single-crystal face-centered cubic metal (Cu, Ag, Pt) nanowires. Here, we report that both Cu and Ag nanowires show significantly increasedmore » ductility and superplasticity under low creep stresses, where the superplasticity is driven by a rate-dependent transition in defect nucleation from twinning to trailing partial dislocations at the micro- or millisecond time scale. The transition in the deformation mechanism also governs a corresponding transition in the stress-dependent creep time at the microsecond (Ag) and millisecond (Cu) time scales. Overall, this work demonstrates the necessity of accessing time scales that far exceed those seen in conventional atomistic modeling for accurate insights into the time-dependent mechanical behavior and properties of nanomaterials.« less

Superplastic Creep of Metal Nanowires from Rate-Dependent Plasticity Transition.

PubMed

Tao, Weiwei; Cao, Penghui; Park, Harold S

2018-05-22

Understanding the time-dependent mechanical behavior of nanomaterials such as nanowires is essential to predict their reliability in nanomechanical devices. This understanding is typically obtained using creep tests, which are the most fundamental loading mechanism by which the time-dependent deformation of materials is characterized. However, due to existing challenges facing both experimentalists and theorists, the time-dependent mechanical response of nanowires is not well-understood. Here, we use atomistic simulations that can access experimental time scales to examine the creep of single-crystal face-centered cubic metal (Cu, Ag, Pt) nanowires. We report that both Cu and Ag nanowires show significantly increased ductility and superplasticity under low creep stresses, where the superplasticity is driven by a rate-dependent transition in defect nucleation from twinning to trailing partial dislocations at the micro- or millisecond time scale. The transition in the deformation mechanism also governs a corresponding transition in the stress-dependent creep time at the microsecond (Ag) and millisecond (Cu) time scales. Overall, this work demonstrates the necessity of accessing time scales that far exceed those seen in conventional atomistic modeling for accurate insights into the time-dependent mechanical behavior and properties of nanomaterials.

Superplastic Creep of Metal Nanowires From Rate-Dependent Plasticity Transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao, Weiwei; Cao, Penghui; Park, Harold S.

Understanding the time-dependent mechanical behavior of nanomaterials such as nanowires is essential to predict their reliability in nanomechanical devices. This understanding is typically obtained using creep tests, which are the most fundamental loading mechanism by which the time dependent deformation of materials is characterized. However, due to existing challenges facing both experimentalists and theorists, the time dependent mechanical response of nanowires is not well-understood. Here, we use atomistic simulations that can access experimental time scales to examine the creep of single-crystal face-centered cubic metal (Cu, Ag, Pt) nanowires. Here, we report that both Cu and Ag nanowires show significantly increasedmore » ductility and superplasticity under low creep stresses, where the superplasticity is driven by a rate-dependent transition in defect nucleation from twinning to trailing partial dislocations at the micro- or millisecond time scale. The transition in the deformation mechanism also governs a corresponding transition in the stress-dependent creep time at the microsecond (Ag) and millisecond (Cu) time scales. Overall, this work demonstrates the necessity of accessing time scales that far exceed those seen in conventional atomistic modeling for accurate insights into the time-dependent mechanical behavior and properties of nanomaterials.« less

Structural efficiency studies of corrugated compression panels with curved caps and beaded webs

NASA Technical Reports Server (NTRS)

Davis, R. C.; Mills, C. T.; Prabhakaran, R.; Jackson, L. R.

1984-01-01

Curved cross-sectional elements are employed in structural concepts for minimum-mass compression panels. Corrugated panel concepts with curved caps and beaded webs are optimized by using a nonlinear mathematical programming procedure and a rigorous buckling analysis. These panel geometries are shown to have superior structural efficiencies compared with known concepts published in the literature. Fabrication of these efficient corrugation concepts became possible by advances made in the art of superplastically forming of metals. Results of the mass optimization studies of the concepts are presented as structural efficiency charts for axial compression.

Effects of an AST program on US titanium story

NASA Technical Reports Server (NTRS)

Fitzsimmons, R. D.

1980-01-01

The singular importance of titanium as the primary structural material for an efficient advanced supersonic transport (AST) is outlined. The advantages of titanium over other metals are shown to apply to future subsonic aircraft as well as for supersonic designs. The cost problem of titanium is addressed and shown to be markedly reduced by the emerging technologies of superplastic forming/diffusion bonding sandwich, hot isostatic pressing of titanium powders, and isothermal forgings if demonstration programs should validate preliminary findings. The impact of a U.S. AST program on the United States titanium supply and demand picture is postulated.

High Temperature Mechanical Behavior of Polycrystalline Alumina from Mixed Nanometer and Micrometer Powders

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.

2001-01-01

Sintered aluminum oxide materials were formed using commercial methods from mechanically mixed powders of nano-and micrometer alumina. The powders were consolidated at 1500 and 1600 C with 3.2 and 7.2 ksi applied stress in argon. The conventional micrometer sized powders failed to consolidate. While 100 percent nanometer-sized alumina and its mixture with the micrometer powders achieved less than 99 percent density. Preliminary high temperature creep behavior indicates no super-plastic strains. However high strains (less than 0.65 percent) were generated in the nanometer powder, due to cracks and linked voids initiated by cavitation.

Aircraft energy efficiency laminar flow control wing design study

NASA Technical Reports Server (NTRS)

Bonner, T. F., Jr.; Pride, J. D., Jr.; Fernald, W. W.

1977-01-01

An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft.

Silicon as anode for high-energy lithium ion batteries: From molten ingot to nanoparticles

NASA Astrophysics Data System (ADS)

Leblanc, Dominic; Hovington, Pierre; Kim, Chisu; Guerfi, Abdelbast; Bélanger, Daniel; Zaghib, Karim

2015-12-01

In this work, we demonstrate that a new mechanical attrition process can be used to prepare nanosilicon powder from metallurgical grade silicon lumps. Composite Li-ion anode made from this nanometer-size powder was found to have a high reversible capacity of 2400 mAh g-1 and an improved cycling stability compared to micrometer-sized powder. It is proposed that improved battery cycling performance is ascribed to the nanoscale silicon particles which supresses the volume expansion owing to its superplasticity.

Multilevel model of polycrystalline materials: grain boundary sliding description

NASA Astrophysics Data System (ADS)

Sharifullina, E.; Shveykin, A.; Trusov, P.

2017-12-01

Material behavior description in a wide range of thermomechanical effects is one of the topical areas in mathematical modeling. Inclusion of grain boundary sliding as an important mechanism of polycrystalline material deformation at elevated temperatures and predominant deformation mechanism of metals and alloys in structural superplasticity allows to simulate various deformation regimes and their transitions (including superplasticity regime with switch-on and switch-off regimes). The paper is devoted to description of grain boundary sliding in structure of two-level model, based on crystal plasticity, and relations for determination the contribution of this mechanism to inelastic deformation. Some results are presented concerning computational experiments of polycrystalline representative volume deformation using developed model.

Growth Kinetics of Magnesio-Aluminate Spinel in Al/Mg Lamellar Composite Interface

NASA Astrophysics Data System (ADS)

Fouad, Yasser; Rabeeh, Bakr Mohamed

The synthesis of Mg-Al2O3 double layered interface is introduced via the application of hot isostatic pressing, HIPing, in Al-Mg foils. Polycrystalline spinel layers are grown experimentally at the interfacial contacts between Al-Mg foils. The growth behavior of the spinel layers along with the kinetic parameters characterizing interface motion and long-range diffusion is established. Low melting depressant (LMD), Zn, and alloying element segregation tends to form micro laminated and/or Nano structure interphase in a lamellar composite solid state processing. Nano composite ceramic interphase materials offer interesting mechanical properties not achievable in other materials, such as superplastic flow and metal-like machinability. Microstructural characterization, mechanical characterization is also established via optical microscopy scanning electron microscopy, energy dispersive X-ray spectroscopy and tensile testing. Chemical and mechanical bonding via inter diffusion processing with alloy segregation are dominant for interphase kinetics. Mechanical characterization with interfacial shear strength is also introduced. HIPing processing is successfully applied on 6082 Al-alloy and AZ31 magnesium alloy for either particulate or micro-laminated interfacial composite processing. The interphase kinetic established through localized micro plasticity, metal flow, alloy segregation and delocalized Al oxide and Mg oxide. The kinetic of interface/interphase induce new nontraditional crack mitigation a long with new bridging and toughening mechanisms.

High Temperature Deformation of Twin-Roll Cast Al-Mn-Based Alloys after Equal Channel Angular Pressing.

PubMed

Málek, Přemysl; Šlapáková Poková, Michaela; Cieslar, Miroslav

2015-11-12

Twin roll cast Al-Mn- and Al-Mn-Zr-based alloys were subjected to four passes of equal channel angular pressing. The resulting grain size of 400 nm contributes to a significant strengthening at room temperature. This microstructure is not fully stable at elevated temperatures and recrystallization and vast grain growth occur at temperatures between 350 and 450 °C. The onset of these microstructure changes depends on chemical and phase composition. Better stability is observed in the Al-Mn-Zr-based alloy. High temperature tensile tests reveal that equal channel angular pressing results in a softening of all studied materials at high temperatures. This can be explained by an active role of grain boundaries in the deformation process. The maximum values of ductility and strain rate sensitivity parameter m found in the Al-Mn-Zr-based alloy are below the bottom limit of superplasticity (155%, m = 0.25). However, some features typical for superplastic behavior were observed-the strain rate dependence of the parameter m , the strengthening with increasing grain size, and the fracture by diffuse necking. Grain boundary sliding is believed to contribute partially to the overall strain in specimens where the grain size remained in the microcrystalline range.

High Temperature Deformation of Twin-Roll Cast Al-Mn-Based Alloys after Equal Channel Angular Pressing

PubMed Central

Málek, Přemysl; Šlapáková Poková, Michaela; Cieslar, Miroslav

2015-01-01

Twin roll cast Al-Mn- and Al-Mn-Zr-based alloys were subjected to four passes of equal channel angular pressing. The resulting grain size of 400 nm contributes to a significant strengthening at room temperature. This microstructure is not fully stable at elevated temperatures and recrystallization and vast grain growth occur at temperatures between 350 and 450 °C. The onset of these microstructure changes depends on chemical and phase composition. Better stability is observed in the Al-Mn-Zr-based alloy. High temperature tensile tests reveal that equal channel angular pressing results in a softening of all studied materials at high temperatures. This can be explained by an active role of grain boundaries in the deformation process. The maximum values of ductility and strain rate sensitivity parameter m found in the Al-Mn-Zr-based alloy are below the bottom limit of superplasticity (155%, m = 0.25). However, some features typical for superplastic behavior were observed—the strain rate dependence of the parameter m, the strengthening with increasing grain size, and the fracture by diffuse necking. Grain boundary sliding is believed to contribute partially to the overall strain in specimens where the grain size remained in the microcrystalline range. PMID:28793667

Laminar flow control SPF/08 feasibility demonstration

NASA Astrophysics Data System (ADS)

Ecklund, R. C.; Williams, N. R.

1981-10-01

The feasibility of applying superplastic forming/diffusion bonding (SPF/DB) technology to laminar flow control (LFC) system concepts was demonstrated. Procedures were developed to produce smooth, flat titanium panels, using thin -0.016 inch sheets, meeting LFC surface smoothness requirements. Two large panels 28 x 28 inches were fabricated as final demonstration articles. The first was flat on the top and bottom sides demonstrating the capability of the tooling and the forming and diffusion bonding procedures to produce flat, defect free surfaces. The second panel was configurated for LFC porous panel treatment by forming channels with dimpled projections on the top side. The projections were machined away leaving holes extending into the panel. A perforated titanium sheet was adhesively bonded over this surface to complete the LFC demonstration panel. The final surface was considered flat enough to meet LFC requirements for a jet transport aircraft in cruising flight.

Design of cryogenic tanks for space vehicles shell structures analytical modeling

NASA Technical Reports Server (NTRS)

Copper, Charles; Mccarthy, K.; Pilkey, W. D.; Haviland, J. K.

1991-01-01

The initial objective was to study the use of superplastically formed corrugated hat section stringers and frames in place of integrally machined stringers over separate frames for the tanks of large launch vehicles subjected to high buckling loads. The ALS was used as an example. The objective of the follow-on project was to study methods of designing shell structures subjected to severe combinations of structural loads and thermal gradients, with emphasis on new combinations of structural arrangements and materials. Typical applications would be to fuselage sections of high speed civil transports and to cryogenic tanks on the National Aerospace Plane.

Analysis of Plastic Flow Instability During Superplastic Deformation of the Zn-Al Eutectoid Alloy Modified with 2 wt.% Cu

NASA Astrophysics Data System (ADS)

Ramos-Azpeitia, Mitsuo; Elizabeth Martínez-Flores, E.; Hernandez-Rivera, Jose Luis; Torres-Villaseñor, Gabriel

2017-11-01

The aim of this work is to analyze the plastic flow instability in Zn-21Al-2Cu alloy deformed under 10-3 s-1 and 513 K, which are optimum conditions for inducing superplastic behavior in this alloy. An evaluation using the Hart and Wilkinson-Caceres criteria showed that the limited stability of plastic flow observed in this alloy is related to low values of the strain-rate sensitivity index ( m) and the strain-hardening coefficient ( γ), combined with the tendency of these parameters to decrease depending on true strain ( ɛ). The reduction in m and γ values could be associated with the early onset of plastic instability and with microstructural changes observed as function of the strain. Grain growth induced by deformation seems to be important during the first stage of deformation of this alloy. However, when ɛ > 0.4 this growth is accompanied by other microstructural rearrangements. These results suggest that in this alloy, a grain boundary sliding mechanism acts to allow a steady superplastic flow only for ɛ < 0.4. For ɛ values between 0.4 and 0.7, observed occurrences of microstructural changes and severe neck formation lead to the supposition that there is a transition in the deformation mechanism. These changes are more evident when ɛ > 0.7 as another mechanism is thought to take over.

SPF/DB primary structure for supersonic aircraft (T-38 horizontal stabilizer)

NASA Technical Reports Server (NTRS)

Delmundo, A. R.; Mcquilkin, F. T.; Rivas, R. R.

1981-01-01

The structural integrity and potential cost savings of superplastic forming/diffusion bonding (SPF/DB) titanium structure for future Supersonic Cruise Research (SCR) and military aircraft primary structure applications was demonstrated. Using the horizontal stabilizer of the T-38 aircraft as a baseline, the structure was redesigned to the existing criteria and loads, using SPF/DB titanium technology. The general concept of using a full-depth sandwich structure which is attached to a steel spindle, was retained. Trade studies demonstrated that the optimum design should employ double-truss, sinewave core in the deepest section of the surface, making a transition to single-truss core in the thinner areas at the leading and trailing edges and at the tip. At the extreme thin edges of the surface, the single-truss core was changed to dot core to provide for gas passages during the SPF/DB process. The selected SPF/DB horizontal stabilizer design consisted of a one-piece SPF/DB sinewave truss core panel, a trunnion fitting, and reinforcing straps. The fitting and the straps were mechanically fastened to the SPF/DB panel.

Plastic Flow and Microstructure Evolution during Thermomechanical Processing of a PM Nickel-Base Superalloy

NASA Astrophysics Data System (ADS)

Semiatin, S. L.; McClary, K. E.; Rollett, A. D.; Roberts, C. G.; Payton, E. J.; Zhang, F.; Gabb, T. P.

2013-06-01

Plastic flow and microstructure evolution during sub- and supersolvus forging and subsequent supersolvus heat treatment of the powder-metallurgy superalloy LSHR (low-solvus, high-refractory) were investigated to develop an understanding of methods that can be used to obtain a moderately coarse gamma grain size under well-controlled conditions. To this end, isothermal, hot compression tests were conducted over broad ranges of temperature [(1144 K to 1450 K) 871 °C to 1177 °C] and constant true strain rate (0.0005 to 10 s-1). At low temperatures, deformation was generally characterized by flow softening and dynamic recrystallization that led to a decrease in grain size. At high subsolvus temperatures and low strain rates, steady-state flow or flow hardening was observed. These latter behaviors were ascribed to superplastic deformation and microstructure evolution characterized by a constant grain size or concomitant dynamic grain growth, respectively. During supersolvus heat treatment following subsolvus deformation, increases in grain size whose magnitude was a function of the prior deformation conditions were noted. A transition in flow behavior from superplastic to nonsuperplastic and the development during forging at a high subsolvus temperature of a wide (possibly bi- or multimodal) gamma-grain-size distribution having some large grains led to a substantially coarser grain size during supersolvus annealing in comparison to that produced under all other forging conditions.

Cryogenic mechanical properties of low density superplastically formable Al-Li alloys

NASA Technical Reports Server (NTRS)

Verzasconi, S. L.; Morris, J. W., Jr.

1989-01-01

The aerospace industry is considering the use of low density, superplastically formable (SPF) materials, such as Al-Li alloys in cryogenic tankage. SPF modifications of alloys 8090, 2090, and 2090+In were tested for strength and Kahn tear toughness. The results were compared to those of similar tests of 2219-T87, an alloy currently used in cryogenic tankage, and 2090-T81, a recently studied Al-Li alloy with exceptional cryogenic properties (1-9). With decreasing temperature, all materials showed an increase in strength, while most materials showed an increase in elongation and decrease in Kahn toughness. The indium addition to 2090 increased alloy strength, but did not improve the strength-toughness combination. The fracture mode was predominantly intergranular along small, recrystallized grains, with some transgranular fracture, some ductile rupture, and some delamination on large, unrecrystallized grains.

Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.

PubMed

Verberne, Berend A; Plümper, Oliver; de Winter, D A Matthijs; Spiers, Christopher J

2014-12-12

Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis. Copyright © 2014, American Association for the Advancement of Science.

The feasibility of producing aluminum-lithium structures for cryogenic tankage applications by laser beam welding

NASA Technical Reports Server (NTRS)

Martukanitz, R. P.; Lysher, K. G.

1993-01-01

Aluminum-lithium alloys exhibit high strength, high elastic modulus, and low density as well as excellent cryogenic mechanical properties making them ideal material candidates for cryogenic tanks. NASA has proposed the use of 'built-up' structure for panels fabricated into cryogenic tanks replacing current conventional machining. Superplastically formed stiffeners would be joined to sheet (tank skin) that had been roll formed to the radius of the tank in order to produce panels. Aluminum-lithium alloys of interest for producing the built-up structure include alloy 2095-T6 stiffeners to 2095-T8 sheet and alloy 8090-T6 stiffeners to 2090-T83 sheet. Laser welding, with comparable joint properties, offers the following advantages over conventional welding: higher production rates, minimal degradation within the heat affected zones, and full process automation. This study established process parameters for laser beam welding, mechanical property determinations, metallographic characterization, and fabrication of prototype panels. Tensile tests representing partial penetration of the skin alloys provided joint efficiencies between 65 and 77 percent, depending upon alloy and degree of penetration. Results of tension shear tests of lap welds indicated that the combination of 2095-T6 to 2090-T8 exhibited significantly higher weld shear strength at the interface in comparison to welds of 8090-T6 to 2090-T83. The increased shear strength associated with 2095 is believed to be due to the alloy's ability to precipitation strengthening (naturally age) after welding.

Low cost, SPF aluminum cryogenic tank structure for ALS

NASA Technical Reports Server (NTRS)

Anton, Claire E.; Rasmussen, Perry; Thompson, Curt; Latham, Richard; Hamilton, C. Howard; Ren, Ben; Gandhi, Chimata; Hardwick, Dallis

1992-01-01

Past production work has shown that cryogenic tank structure for the Shuttle Booster Rockets and the Titan system have very high life cycle costs for the fuel tank structure. The tanks are machined stiffener-skin combination that are subsequently formed into the required contour after machining. The material scrap rate for these configurations are usually high, and the loss of a tank panel due to forming or heat treatment problems is very costly. The idea of reducing the amount of scrap material and scrapped structural members has prompted the introduction of built-up structure for cryogenic tanks to be explored on the ALS program. A build-up structure approach that has shown improvements in life cycle cost over the conventional built-up approach is the use of superplastically formed (SPF) stiffened panels (reducing the overall part count and weight for the tank) resistance spot welded (RSW) to outer tank skin material. The stiffeners provide for general stability of the tank, while the skin material provides hoop direction continuity for the loads.

Texture evolution during low temperature superplasticity in 5083 and 5052 Al-Mg alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, S.W.; Hsiao, I.C.; Huang, J.C.

2000-07-01

Low temperature superplasticity (LTSP) at 250 C and 1 x 10{sup {minus}3} s{sup {minus}1} was observed in the 5083 Al-Mg base alloy after thermomechanical treatments (TMT). With increasing TMT rolling strain, the high angle grain boundary fraction increased, more favorable for the further operation of grain boundary sliding and LTSP. The strong texture components and bimodal misorientation distributions present after TMT were not affected by static annealing at 250 C, but evolved gradually into a random orientation distribution during LTSP straining from 30% to 100%. When the LTSP elongation was greater than 150%, the macro-deformation anisotropy R ratio would finallymore » reach a stable level. It seems that the LTSP performance was controlled by a large fraction of high angle boundaries, but not by the special coincidence site lattice boundaries.« less

Study of the application of superplastically formed and diffusion bonded (SPF/DB) titanium structure to laminar flow control (LFC) wing design

NASA Technical Reports Server (NTRS)

Mcquilkin, F. T.

1979-01-01

Eighteen design concepts for a LFC wing cover, using various SPF/DB approaches, were developed. After evaluation of producibility, compatibility with LFC requirements, structural efficiency and fatigue requirements, three candidates were selected for fabrication of demonstration panels. Included were both sandwich and stiffened semi-sandwich panels with slotted and perforated surfaces. Subsequent to the evaluation of the three demonstration panels, one concept was selected for fabrication of a 0.3 x 1.0 meter (12 x 42 inch) feasibility panel. It was a stiffened, semi-sandwich panel with a slotted surface, designed to meet the requirements of the upper wing cover at the maximum wing bending moment of the baseline configuration.

Maintaining High Strength in Mg-LPSO Alloys with Low Yttrium Content Using Severe Plastic Deformation.

PubMed

Garces, Gerardo; Cabeza, Sandra; Barea, Rafael; Pérez, Pablo; Adeva, Paloma

2018-05-05

Alternative processing routes such as powder metallurgy, the extrusion of recycled chips, or equal channel angular pressing (ECAP) have been considered for effective methods of maintaining the high mechanical strength of Mg-Y-Zn alloys containing long-period stacking ordered structures with respect to the alloy processed by the conventional extrusion of as-cast ingots with the advantage of minimizing the yttrium content. A yield stress similar to that found for extruded Mg 97 Y₂Zn₁ alloy can be attained with only half of the usual yttrium and zinc additions thanks to the grain refinement induced by ECAP processing. The properties of Mg 98.5 Y₁Zn 0.5 subjected to ECAP are maintained up to 200 °C, but superplastic behavior is found above this temperature when the alloy is processed through a powder metallurgy route.

Effect of thermal treatment on the bio-corrosion and mechanical properties of ultrafine-grained ZK60 magnesium alloy.

PubMed

Choi, H Y; Kim, W J

2015-11-01

The combination of solid solution heat treatments and severe plastic deformation by high-ratio differential speed rolling (HRDSR) resulted in the formation of an ultrafine-grained microstructure with high thermal stability in a Mg-5Zn-0.5Zr (ZK60) alloy. When the precipitate particle distribution was uniform in the matrix, the internal stresses and dislocation density could be effectively removed without significant grain growth during the annealing treatment (after HRDSR), leading to enhancement of corrosion resistance. When the particle distribution was non-uniform, rapid grain growth occurred in local areas where the particle density was low during annealing, leading to development of a bimodal grain size distribution. The bimodal grain size distribution accelerated corrosion by forming a galvanic corrosion couple between the fine-grained and coarse-grained regions. The HRDSR-processed ZK60 alloy with high thermal stability exhibited high corrosion resistance, high strength and high ductility, and excellent superplasticity, which allow the fabrication of biodegradable magnesium devices with complicated designs that have a high mechanical integrity throughout the service life in the human body. Copyright © 2015 Elsevier Ltd. All rights reserved.

A novel approach to determine the thermal transition of gum powder/hydro-gels using dynamic mechanical analysis

NASA Astrophysics Data System (ADS)

Nagamadhu, M.; Jeyaraj, P.; Kumar, G. C. Mohan

2018-04-01

The dynamic characterization of materials plays a major role in the present area. The many researchers are worked on solid materials and its characterization, it can be tested using dynamic mechanical analyzer (DMA), however, no such work on powder a semiliquid samples. The powder and liquid samples can also easily characterization as like solid samples using DMA. These powder samples are analyzed with a material pocket method which can be used to accurately determine very low levels of variation in powder properties, due to the high sensitivity of DMA to glass transitions. No such DMA studies on hydrogel and Gum powders. The gum powders are used in various applications start from food industries, pharmacy, natural gums paste, biomedical applications etc. among all this applications gum Ghatti is one of the powders using for varies applications. Around 50 milligrams of Ghatti powders are placed inside material pocket and analyzed storage modulus (G'), loss modulus (G″) and tan delta (δ). Also, understand the curing and glass transition effect using water, glycerin and superplastic from room temperature to 200°C. The result shows that storage modulus decreases with increase in temperature in pure Ghatti powder. The surprising improvement in storage modulus was found with an increase in temperature with addition of water, glycerin, and superplastic. However, loss modulus and tan delta are also having very significant influence and also shows a clear peak of the tan delta. The loss modulus results were found to be improved by adding solidifying agents, along with this water and superplastic better influence. But glycerine found to be hydrogel in nature and thermodynamic properties are much influenced by frequency.

Design studies of Laminar Flow Control (LFC) wing concepts using superplastics forming and diffusion bonding (SPF/DB)

NASA Technical Reports Server (NTRS)

Wilson, V. E.

1980-01-01

Alternate concepts and design approaches were developed for suction panels and techniques were defined for integrating these panel designs into a complete LFC 200R wing. The design concepts and approaches were analyzed to assure that they would meet the strength, stability, and internal volume requirements. Cost and weight comparisions of the concepts were also made. Problems of integrating the concepts into a complete aircraft system were addressed. Methods for making splices both chordwise and spanwise, fuel light joints, and internal duct installations were developed. Manufacturing problems such as slot aligment, tapered slot spacing, production methods, and repair techniques were addressed. An assessment of the program was used to developed recommendations for additional research in the development of SPF/DB for LFC structure.

High-temperature deformation processing of Ti-24Al-20Nb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagar, P.K.; Banerjee, D.; Muraleedharan, K.

1996-09-01

Power dissipation maps have been generated in the temperature range of 900 C to 1,150 C and strain rate range of 10{sup {minus}3} to 10 s{sup {minus}1} for a cast aluminide alloy Ti-24Al-20Nb using dynamic material model. The results define two distinct regimes of temperature and strain rate in which efficiency of power dissipation is maximum. The first region, centered around 975 C/0.1 s{sup {minus}1}, is shown to correspond to dynamic recrystallization of the {alpha}{sub 2} phase and the second, centered around 1,150 C/0.001 s{sup {minus}1}, corresponds to dynamic recovery and superplastic deformation of the {beta} phase. Thermal activation analysismore » using the power law creep equation yielded apparent activation energies of 854 and 627 kJ/mol for the first and second regimes, respectively. Reanalyzing the data by alternate methods yielded activation energies in the range of 170 to 220 kJ/mol and 220 to 270 kJ/mol for the first and second regimes, respectively. Cross slip was shown to constitute the activation barrier in both cases. Two distinct regimes of processing instability--one at high strain rates and the other at the low strain rates in the lower temperature regions--have been identified, within which shear bands are formed.« less

Noise and economic characteristics of an advanced blended supersonic transport concept

NASA Technical Reports Server (NTRS)

Molloy, J. K.; Grantham, W. D.; Neubauer, M. J., Jr.

1982-01-01

Noise and economic characteristics were obtained for an advanced supersonic transport concept that utilized wing body blending, a double bypass variable cycle engine, superplastically formed and diffusion bonded titanium in both the primary and secondary structures, and an alternative interior arrangement that provides increased seating capacity. The configuration has a cruise Mach number of 2.62, provisions for 290 passengers, a mission range of 8.19 Mm (4423 n.mi.), and an average operating cruise lift drag ratio of 9.23. Advanced operating procedures, which have the potential to reduce airport community noise, were explored by using a simulator. Traded jet noise levels of 105.7 and 103.4 EPNdB were obtained by using standard and advanced takeoff operational procedures, respectively. A new method for predicting lateral attenuation was utilized in obtaining these jet noise levels.

Power metallurgy approaches to high temperature components for gas turbine engines

NASA Technical Reports Server (NTRS)

Probst, H. B.

1974-01-01

Work conducted by NASA and NASA contractors on prealloyed superalloy powders and materials strengthened by oxide dispersion is reviewed. Fabrication, tensile strength, superplasticity, grain growth control, stress rupture life, and grain-size and dispersion-level effects are covered. Distinct strength advantages of powder metallurgy superalloys over conventional wrought alloys are noted.

Superplasticity in Fine-Grained Ceramics

DTIC Science & Technology

1994-01-31

Stabilized, Tetragonal Zirconia," Acta Metall. Mater., 39(12), (1991), pp. 3227-3236. 10. B. Kellett, P. Carry, and A. Mocellin , "Extrusion of Tet-ZrO2...F. Wakai, S. Sakaguchi, and H. Kato, J. Ceram. Soc. Jap., 94, 72 (1986). 8. B. Kellett, P. Carry, and A. Mocellin , J. Amer. Ceram. Soc., 74, 1922

Comparative Study of Several Energy Dissipating Devices

NASA Astrophysics Data System (ADS)

Abdul-Latif, A.

2011-11-01

Large plastic lateral collapse problem of two geometrically identical hollow cylinders under compressive load is of particular interest in this work, since, the energy absorbed can be characterized by a smooth loaded deflection relation, and these tubes are also easier to build than most other devices. Cylinders of various geometrical parameters (i.e., inside/outside diameter ratios: R = di/do ranging from 0 to 0.473) are used having the same cross-sectional area and length. Superplastic material used in this study has a considerably sensitivity to the quasi-static strain rate in the range of (10-5 to 10-3/s). Hence, this material could be employed as a representative material to simulate the classical engineering material behavior under high strain rate. Comparative study of different structural situations is conducted using four energy dissipating devices designed and investigated by the author in previous works. They are: (1) two geometrically identical cylinders made of superplastic tin-lead alloy can freely expand along their sides and lengths; (2) two cylinders are the same as in (1) but not allowed to expand along their sides and lengths; (3) one cylinder is made from superplastic and the other made from steel and free to deform along its sides and length; (4) the same as in (3) but the cylinder is not allowed to expand along its sides and length. Based on the obtained experimental results, the features of each device in dissipating the energy during the large plastic collapse are investigated. It is concluded that the energy absorbed for a given system decreases with the increase of the R ratio. It is recognized that the highest absorbed energy is obtained in the constrained situation with deformable non-deformable compared to the other situations. Moreover, through the finite element simulations, the flow mechanism in each device is studied and compared to the experimental results.

Nanoscale alloys and core-shell materials: Model predictions of the nanostructure and mechanical properties

NASA Astrophysics Data System (ADS)

Zhurkin, E. E.; van Hoof, T.; Hou, M.

2007-06-01

Atomic scale modeling methods are used to investigate the relationship between the properties of clusters of nanometer size and the materials that can be synthesized by assembling them. The examples of very different bimetallic systems are used. The first one is the Ni3Al ordered alloy and the second is the AgCo core-shell system. While the Ni3Al cluster assembled materials modeling is already reported in our previous work, here we focus on the prediction of new materials synthesized by low energy deposition and accumulation of AgCo clusters. It is found that the core-shell structure is preserved by deposition with energies typical of low energy cluster beam deposition, although deposition may induce substantial cluster deformation. In contrast with Ni3Al deposited cluster assemblies, no grain boundary between clusters survives deposition and the silver shells merge into a noncrystalline system with a layered structure, in which the fcc Co grains are embedded. To our knowledge, such a material has not yet been synthesized experimentally. Mechanical properties are discussed by confronting the behaviors of Ni3Al and AgCo under the effect of a uniaxial load. To this end, a molecular dynamics scheme is established in view of circumventing rate effects inherent to short term modeling and thereby allowing to examine large plastic deformation mechanisms. Although the mechanisms are different, large plastic deformations are found to improve the elastic properties of both the Ni3Al and AgCo systems by stabilizing their nanostructure. Beyond this improvement, when the load is further increased, the Ni3Al system displays reduced ductility while the AgCo system is superplastic. The superplasticity is explained by the fact that the layered structure of the Ag system is not modified by the deformation. Some coalescence of the Co grains is identified as a geometrical effect and is suggested to be a limiting factor to superplasticity.

Finite Element Modeling of Dieless Tube Drawing of Strain Rate Sensitive Material with Coupled Thermo-Mechanical Analysis

NASA Astrophysics Data System (ADS)

Furushima, Tsuyoshi; Sakai, Takashi; Manabe, Ken-ichi

2004-06-01

Dieless drawing is a unique deformation process without conventional dies, which can achieve a great reduction of wire and tube metals in single pass by means of local heating and cooling approach. In this study, for microtube forming, the dieless drawing process applying superplastic behavior was analyzed by finite element method (FEM) in order to clarify the effect of dieless tube drawing conditions such as tensile speed, moving speed of heating and cooling system, and material properties on deformation behavior of the tube. In the calculation, the material properties were dealt in a special subroutine, whose constitutive equation was defined as σ = Kɛnɛ˙m, and was linked to the solver. A coupled thermo-mechanical analysis was performed for the dieless tube drawing using the FEM. In the thermal analysis of dieless tube drawing, heat transfer was introduced to calculate the heat flux between heating coil and tube surface, and heat conduction in a tube. The influence of dieless tube drawing conditions on deformation behavior was clarified. As a result, for the strain rate sensitive material, the maximum reduction of area and the minimum outer diameter in single pass attain to 90.9% and 2.56mm, respectively. From the result, it is concluded that the dieless tube drawing is essential to produce an extrafine microtube by reason of keeping cylindrical tube diameter ratio constant with extremely high reduction.

Predicting Hot Deformation of AA5182 Sheet

NASA Astrophysics Data System (ADS)

Lee, John T.; Carpenter, Alexander J.; Jodlowski, Jakub P.; Taleff, Eric M.

Aluminum 5000-series alloy sheet materials exhibit substantial ductilities at hot and warm temperatures, even when grain size is not particularly fine. The relatively high strain-rate sensitivity exhibited by these non-superplastic materials, when deforming under solute-drag creep, is a primary contributor to large tensile ductilities. This active deformation mechanism influences both plastic flow and microstructure evolution across conditions of interest for hot- and warm-forming. Data are presented from uniaxial tensile and biaxial bulge tests of AA5182 sheet material at elevated temperatures. These data are used to construct a material constitutive model for plastic flow, which is applied in finite-element-method (FEM) simulations of plastic deformation under multiaxial stress states. Simulation results are directly compared against experimental data to explore the usefulness of this constitutive model. The effects of temperature and stress state on plastic response and microstructure evolution are discussed.

Identification of Deformation Mechanisms During Bi-Axial Straining of Superplastic AA5083 Material

DTIC Science & Technology

2004-06-01

equiaxed grain structure in FSS along with the prevalence of high - energy boundaries accommodates sliding under the proper shearing conditions. Figure...by a randomized texture and a higher concentration of high disorientation angles. Dislocation creep, which dominates at higher strain rates, is...concentration of high disorientation angles. Dislocation creep, which dominates at higher strain rates, is characterized by fiber texture formation

Mechanisms of Superplastic Deformation of Nanocrystalline Silicon Carbide Ceramics

DTIC Science & Technology

2012-08-01

These included the following: standard hot isostatic pressing (HIP), spark plasma sintering , ultra-high pressure HIP, and a multianvil pressure...96.8 2270 Multianvil apparatus 1200 3000 94.8 1130 Note: SPS = spark plasma sintering . 2 Figure 1. Ultra-high pressure HIP; 1600 °C, 980...strain rate sensitivity and flow stress. 15. SUBJECT TERMS silicon carbide, nanostructure, sintering , hot isostatic pressing, hardness 16. SECURITY

Mechanical behavior and modelisation of Ti-6Al-4V titanium sheet under hot stamping conditions

NASA Astrophysics Data System (ADS)

Sirvin, Q.; Velay, V.; Bonnaire, R.; Penazzi, L.

2017-10-01

The Ti-6Al-4V titanium alloy is widely used for the manufacture of aeronautical and automotive parts (solid parts). In aeronautics, this alloy is employed for its excellent mechanical behavior associated with low density, outstanding corrosion resistance and good mechanical properties up to 600°C. It is especially used for the manufacture of fuselage frames, on the pylon for carrying out the primary structure (machining forged blocks) and the secondary structure in sheet form. In this last case, the sheet metal forming can be done through various methods: at room temperature by drawing operation, at very high temperature (≃900°C) by superplastic forming (SPF) and at intermediate temperature (≥750°C) by hot forming (HF). In order to reduce production costs and environmental troubles, the cycle times reduction associated with a decrease of temperature levels are relevant. This study focuses on the behavior modelling of Ti-6Al-4V alloy at temperatures above room temperature to obtained greater formability and below SPF condition to reduce tools workshop and energy costs. The displacement field measurement obtained by Digital Image Correlation (DIC) is based on innovative surface preparation pattern adapted to high temperature exposures. Different material parameters are identified to define a model able to predict the mechanical behavior of Ti-6Al-4V alloy under hot stamping conditions. The hardening plastic model identified is introduced in FEM to simulate an omega shape forming operation.

JPRS Report, Science & Technology, Japan, 28th Ceramics Science Discussion

DTIC Science & Technology

1990-11-13

U non doped "5 Ag powder A 60 120 180 140 300 Temperature (K) Figure 1. Plots or Resistivity Vs. Temperature for YBa 2 Cu 30Y to Which Different...Yasuharu Kodama, et al.] ........................ 13 -a - Superplasticity of Hydroxyapatite [Fumihiro Wakai, Yasuharu Kodama, et al...67 Synthesis of Ag -Added Bi-Pb-Ca-Cu-O Powder by Spray Drying, Superconductivity of Powder [Hiroko Higuma, Mitsunobu Wakata, et al

Superplasticity. Revision

DTIC Science & Technology

1989-09-01

angle to the applied tension and failure rapidly follows, as the volume of metal now deforming is small. Local necking Contributes virtually nothing...into components. It is thought that the 9 phase may be responsible for grain refinement, but it may be due to minute traces of oxide on the original...order to minimize oxidation and related detrimental surface degradation due to the reactivity of titanium. The use of such protective gases is not

Continuous Severe Plastic Deformation Processing of Aluminum Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raghavan Srinivasan; Prabir K. Chaudhury; Balakrishna Cherukuri

2006-06-30

Metals with grain sizes smaller than 1-micrometer have received much attention in the past decade. These materials have been classified as ultra fine grain (UFG) materials (grain sizes in the range of 100 to 1000-nm) and nano-materials (grain size <100-nm) depending on the grain size. This report addresses the production of bulk UFG metals through the use of severe plastic deformation processing, and their subsequent use as stock material for further thermomechanical processing, such as forging. A number of severe plastic deformation (SPD) methods for producing bulk UFG metals have been developed since the early 1990s. The most promising ofmore » these processes for producing large size stock that is suitable for forging is the equal channel angular extrusion or pressing (ECAE/P) process. This process involves introducing large shear strain in the work-piece by pushing it through a die that consists of two channels with the same cross-sectional shape that meet at an angle to each other. Since the cross-sections of the two channels are the same, the extruded product can be re-inserted into the entrance channel and pushed again through the die. Repeated extrusion through the ECAE/P die accumulates sufficient strain to breakdown the microstructure and produce ultra fine grain size. It is well known that metals with very fine grain sizes (< 10-micrometer) have higher strain rate sensitivity and greater elongation to failure at elevated temperature, exhibiting superplastic behavior. However, this superplastic behavior is usually manifest at high temperature (> half the melting temperature on the absolute scale) and very low strain rates (< 0.0001/s). UFG metals have been shown to exhibit superplastic characteristics at lower temperature and higher strain rates, making this phenomenon more practical for manufacturing. This enables part unitization and forging more complex and net shape parts. Laboratory studies have shown that this is particularly true for UFG metals produced by SPD techniques. This combination of properties makes UFG metals produced by SPD very attractive as machining, forging or extrusion stock, both from the point of view of formability as well as energy and cost saving. However, prior to this work there had been no attempt to transfer these potential benefits observed in the laboratory scale to industrial shop floor. The primary reason for this was that the laboratory scale studies had been conducted to develop a scientific understanding of the processes that result in grain refinement during SPD. Samples that had been prepared in the laboratory scale were typically only about 10-mm diameter and 50-mm long (about 0.5-inch diameter and 2-inches long). The thrust of this project was three-fold: (i) to show that the ECAE/P process can be scaled up to produce long samples, i.e., a continuous severe plastic deformation (CSPD) process, (ii) show the process can be scaled up to produce large cross section samples that could be used as forging stock, and (iii) use the large cross-section samples to produce industrial size forgings and demonstrate the potential energy and cost savings that can be realized if SPD processed stock is adopted by the forging industry. Aluminum alloy AA-6061 was chosen to demonstrate the feasibility of the approach used. The CSPD process developed using the principles of chamber-less extrusion and drawing, and was demonstrated using rolling and wire drawing equipment that was available at Oak Ridge National Laboratory. In a parallel effort, ECAE/P dies were developed for producing 100-mm square cross section SPD billets for subsequent forging. This work was carried out at Intercontinental Manufacturing Co. (IMCO), Garland TX. Forging studies conducted with the ECAE/P billets showed that many of the potential benefits of using UFG material can be realized. In particular, the material yield can be increased, and the amount of material that is lost as scrap can be reduced by as much as 50%. Forging temperatures can also be reduced by over 150ºC, resulting in energy savings in the operation of billet heating furnaces. Looking at only the energy required to make forgings from stock materials, estimated energy savings associated with reduced scrap and lower furnace operating temperatures were greater than 40% if ECAE/P stock material was used instead of conventionally extruded stock. Subsequent heat treatment of the forged materials to the T6 condition showed that the mechanical properties of parts made from the ECAE/P stock material were the same as of those made from conventional extruded stock material. Therefore, the energy and cost savings benefits can be realized by the use SPD processed material as forging stock without sacrificing properties in the final part.« less

Ultrahigh Carbon Steel.

DTIC Science & Technology

1984-10-01

The unique mechanical properties achieved in UHC steels are due to the presence of micron-size ferrite grains and ultrafine spheroidized carbides. SN...unique mechanical properties achieved in UHC [0 steels are due to the presence of micron-size ferrite grains and ultrafine spheroidized carbides. 0... steel is that it has a low resistance to plastic flow upon deformation in the superplastic range at low strain rates (e.g., 2000 psi at 4 1041 e 10 s

Investigation of immiscible systems and potential applications

NASA Technical Reports Server (NTRS)

Markworth, A. J.; Oldfield, W.; Duga, J.; Gelles, S. H.

1975-01-01

The droplet coalescence kinetics at 0 g and 1 g were considered for two systems which contained liquid droplets in a host liquid. One of these (Al-In) typified a system containing a liquid phase miscibility gap and the order (oil-water) a mixture of two essentially insoluble liquids. A number of coalescence mechanisms potentially prominent at low g in this system were analyzed and explanations are presented for the observed unusual stability of the emulsion. Ground base experiments were conducted on the coalescence of In droplets in and Al-In alloy during cooling through the miscibility gap at different cooling rates. These were in qualitative agreement with the computer simulation. Potential applications for systems with liquid phase miscibility gaps were explored. Possibilities included superconductors, electrical contact materials, superplastic materials, catalysts, magnetic materials, and others. The role of space processing in their production was also analyzed.

Electrocatalysis-induced elasticity modulation in a superionic proton conductor probed by band-excitation atomic force microscopy.

PubMed

Papandrew, A B; Li, Q; Okatan, M B; Jesse, S; Hartnett, C; Kalinin, S V; Vasudevan, R K

2015-12-21

Variable temperature band-excitation atomic force microscopy in conjunction with I-V spectroscopy was used to investigate the crystalline superionic proton conductor CsHSO4 during proton exchange induced by a Pt-coated conductive scanning probe. At a sample temperature of 150 °C and under an applied bias <1 V, reduction currents of up to 1 nA were observed. Simultaneously, we show that the electrochemical reactions are accompanied by a reversible decrease in the elastic modulus of CsHSO4, as seen by a contact resonance shift, and find evidence for superplasticity during scanning. These effects were not observed in the room-temperature phase of CsHSO4 or in the case of catalytically inactive conductive probes, proving the utility of this technique for monitoring electrochemical processes on the nanoscale, as well as the use of local contact stiffness as a sensitive indicator of electrochemical reactions.

Enhanced Densification of White Cast Iron Powders by Cyclic Phase Transformations under Stress.

DTIC Science & Technology

1981-08-01

Little or no significant enhancement in densification was reported in these cases where no applied stresses were used. Kohara [9) extended this work...enhancement of densification observed by Kohara , although limited, was attributed to the occurrence of transformation superplasticity. As will be shown... Kohara : Metall. Trans., 1976, vol. 7, p. 1239. 10. Y. Oshida, J. Jpn. Soc, Powder and Powder Metall., 1975, vol. 22, p. 147. 11. M. de Jong and G. W

TAZ-8A Alloy Increases The Thermal Endurance Of Steel

NASA Technical Reports Server (NTRS)

Waters, William J.

1990-01-01

TAZ-8A exhibits high strength at temperatures as high as 1,400 degrees F (760 degrees C) and resistance to oxidation; also exhibits excellent cyclic shock resistance between 600 and 2,000 degrees F (316 and 1,093 degrees C) and superplasticity at 1,800 degrees F (982 degrees C). Converts into fine powder and then flame-, plasma-, arc-, or wire-sprayed onto inexpensive steel substrate. Surface treatment with this alloy prolongs service life and reduces costs.

Microstructure Evolution and Mechanical Behavior of Ultrafine Ti-6Al-4V During Low Temperature Superplastic Deformation (Postprint)

DTIC Science & Technology

2016-09-13

through the deformed β matrix . A total elongation of 1000% and strain-rate-sensitivity exponent m = 0.48 were obtained at 550 °C and 2 × 10−4 s−1...two orders of magnitude faster than the corresponding static behaviors due to enhanced diffusion through the deformed b matrix . A total elongation of...various metallic materials, including titanium alloys, is usually the result of concurrent grain- or interphase-boundary sliding, grain- matrix

Superplastic Behavior of Ti-6Al-4V-0.1B Alloy (Preprint)

DTIC Science & Technology

2011-10-01

Scott (UES, Inc.) for help with running the high temperature tension tests. The Ti-6Al-4V-0.1B sheets used in this study were fabricated in...collaboration with Scott Reed (Flowserve) and Oscar Yu (RTI) under EMTEC Project CT-86. 6 Approved for public release; distribution unlimited. References...Sun, M. Bennett, and J.M. Scott , “Production of Plates and Sheets from As-Cast Ti-6Al-4V via Boron Modification”, in: Ti-2007 Science and Technology

Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

PubMed

Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

2015-06-01

Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development and analysis of a STOL supersonic cruise fighter concept

NASA Technical Reports Server (NTRS)

Dollyhigh, S. M.; Foss, W. E., Jr.; Morris, S. J., Jr.; Walkley, K. B.; Swanson, E. E.; Robins, A. W.

1984-01-01

The application of advanced and emerging technologies to a fighter aircraft concept is described. The twin-boom fighter (TBF-1) relies on a two dimensional vectoring/reversing nozzle to provide STOL performance while also achieving efficient long range supersonic cruise. A key feature is that the propulsion package is placed so that the nozzle hinge line is near the aircraft center-of-gravity to allow large vector angles and, thus, provide large values of direct lift while minimizing the moments to be trimmed. The configurations name is derived from the long twin booms extending aft of the engine to the twin vertical tails which have a single horizontal tail mounted atop and between them. Technologies utilized were an advanced engine (1985 state-of-the-art), superplastic formed/diffusion bonded titanium structure, advanced controls/avionics/displays, supersonic wing design, and conformal weapons carriage. The integration of advanced technologies into this concept indicate that large gains in takeoff and landing performance, maneuver, acceleration, supersonic cruise speed, and range can be acieved relative to current fighter concepts.

NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

1993-01-01

The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program continues a high level of activity. Progress achieved between 1 Jan. and 30 Jun. 1993 is reported. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The following projects are addressed: environmental fatigue of Al-Li-Cu alloys; mechanisms of localized corrosion and environmental fracture in Al-Cu-Li-Mg-Ag alloy X2095 and compositional variations; the effect of zinc additions on the precipitation and stress corrosion cracking behavior of alloy 8090; hydrogen interactions with Al-Li-Cu alloy 2090 and model alloys; metastable pitting of aluminum alloys; cryogenic fracture toughness of Al-Cu-Li + In alloys; the fracture toughness of Weldalite (TM); elevated temperature cracking of advanced I/M aluminum alloys; response of Ti-1100/SCS-6 composites to thermal exposure; superplastic forming of Weldalite (TM); research to incorporate environmental effects into fracture mechanics fatigue life prediction codes such as NASA FLAGRO; and thermoviscoplastic behavior.

JPRS report: Science and technology. Central Eurasia

NASA Astrophysics Data System (ADS)

1994-08-01

Translated articles cover the following topics: boronizing laser treatment of titanium alloys; argon-arc welding-on titanium dowels to inserts for aircraft structures made of composite materials; method of reducing level of thermally stressed state of gas turbine engine blades by selecting optimum thickness distribution of ceramic heat shield coating; certifying modern ceramics for mechanical properties; superplastic ceramic: possibilities for application in modeling pressworking manufacturing processes; monitoring strength of ceramics by acoustic emission; physical and mechanical properties of Al2O3 + ZrO2:Y2O3 composite produced by directional crystallization from melt; influence that microalloying with rare earth elements has on resistance of steels to deformation and fracture under alternating elastic-plastic loading; conceptions of constructing information management networks for distributed objects; concept of a document information system based on an object-oriented subject-area model; underground future of rocket technologies; geoinformation approach to organizing automated information systems for regional-local monitoring of atmospheric pollutants; and possibility of using lidar wind sounding in climatic-ecologic monitoring of limited areas.

Strain Amount Dependent Grain Size and Orientation Developments during Hot Compression of a Polycrystalline Nickel Based Superalloy

PubMed Central

He, Guoai; Tan, Liming; Liu, Feng; Huang, Lan; Huang, Zaiwang; Jiang, Liang

2017-01-01

Controlling grain size in polycrystalline nickel base superalloy is vital for obtaining required mechanical properties. Typically, a uniform and fine grain size is required throughout forging process to realize the superplastic deformation. Strain amount occupied a dominant position in manipulating the dynamic recrystallization (DRX) process and regulating the grain size of the alloy during hot forging. In this article, the high-throughput double cone specimen was introduced to yield wide-range strain in a single sample. Continuous variations of effective strain ranging from 0.23 to 1.65 across the whole sample were achieved after reaching a height reduction of 70%. Grain size is measured to be decreased from the edge to the center of specimen with increase of effective strain. Small misorientation tended to generate near the grain boundaries, which was manifested as piled-up dislocation in micromechanics. After the dislocation density reached a critical value, DRX progress would be initiated at higher deformation region, leading to the refinement of grain size. During this process, the transformations from low angle grain boundaries (LAGBs) to high angle grain boundaries (HAGBs) and from subgrains to DRX grains are found to occur. After the accomplishment of DRX progress, the neonatal grains are presented as having similar orientation inside the grain boundary. PMID:28772514

Deep focus earthquakes in the laboratory

NASA Astrophysics Data System (ADS)

Schubnel, Alexandre; Brunet, Fabrice; Hilairet, Nadège; Gasc, Julien; Wang, Yanbin; Green, Harry W., II

2014-05-01

While the existence of deep earthquakes have been known since the 1920's, the essential mechanical process responsible for them is still poorly understood and remained one of the outstanding unsolved problems of geophysics and rock mechanics. Indeed, deep focus earthquake occur in an environment fundamentally different from that of shallow (<100 km) earthquakes. As pressure and temperature increase with depth however, intra-crystalline plasticity starts to dominate the deformation regime so that rocks yield by plastic flow rather than by brittle fracturing. Olivine phase transitions have provided an attractive alternative mechanism for deep focus earthquakes. Indeed, the Earth mantle transition zone (410-700km) is the locus of the two successive polymorphic transitions of olivine. Such scenario, however, runs into the conceptual barrier of initiating failure in a pressure (P) and temperature (T) regime where deviatoric stress relaxation is expected to be achieved through plastic flow. Here, we performed laboratory deformation experiments on Germanium olivine (Mg2GeO4) under differential stress at high pressure (P=2-5GPa) and within a narrow temperature range (T=1000-1250K). We find that fractures nucleate at the onset of the olivine to spinel transition. These fractures propagate dynamically (i.e. at a non-negligible fraction of the shear wave velocity) so that intense acoustic emissions are generated. Similar to deep-focus earthquakes, these acoustic emissions arise from pure shear sources, and obey the Gutenberg-Richter law without following Omori's law. Microstructural observations prove that dynamic weakening likely involves superplasticity of the nanocrystalline spinel reaction product at seismic strain rates. Although in our experiments the absolute stress value remains high compared to stresses expected within the cold core of subducted slabs, the observed stress drops are broadly consistent with those calculated for deep earthquakes. Constant differential stress conditions at failure over a wide range of confinement (2-5GPa) strongly suggest that transformational faulting is largely independent of normal stress and thus involves non-frictional processes. We suggest that rupture nucleation is controlled by dislocation density and spinel nucleation kinetics, while propagation is controlled by superplastic flow. High stress and high dislocation density conditions can be met in a cold subducting slab full of metastable olivine, due to stress concentrations at the micro and mesoscopic scales because of buckling, folding, and/or inherited fractures. This is particularly true in the Tonga-Kermadec region for instance, for which the largest catalog of deep focus earthquake is available.

Energy efficient engine shroudless, hollow fan blade technology report

NASA Technical Reports Server (NTRS)

Michael, C. J.

1981-01-01

The Shroudless, Hollow Fan Blade Technology program was structured to support the design, fabrication, and subsequent evaluation of advanced hollow and shroudless blades for the Energy Efficient Engine fan component. Rockwell International was initially selected to produce hollow airfoil specimens employing the superplastic forming/diffusion bonding (SPF/DB) fabrication technique. Rockwell demonstrated that a titanium hollow structure could be fabricated utilizing SPF/DB manufacturing methods. However, some problems such as sharp internal cavity radii and unsatisfactory secondary bonding of the edge and root details prevented production of the required quantity of fatigue test specimens. Subsequently, TRW was selected to (1) produce hollow airfoil test specimens utilizing a laminate-core/hot isostatic press/diffusion bond approach, and (2) manufacture full-size hollow prototype fan blades utilizing the technology that evolved from the specimen fabrication effort. TRW established elements of blade design and defined laminate-core/hot isostatic press/diffusion bonding fabrication techniques to produce test specimens. This fabrication technology was utilized to produce full size hollow fan blades in which the HIP'ed parts were cambered/twisted/isothermally forged, finish machined, and delivered to Pratt & Whitney Aircraft and NASA for further evaluation.

Thermal analysis of 3-mol%-yttria-stabilized tetragonal zirconia powder doped with copper oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seidensticker, J.R.; Mayo, M.J.

Thermal analysis was performed upon 3-mol%-yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) which had been doped with CuO using an aqueous adsorption technique. Cyclic differential thermal analysis (DTA) scans indicated that the CuO present on the powder surfaces first transforms to Cu{sub 2}O and then melts. The molten Cu{sub 2}O then reacts with yttria at the powder surfaces to form a new phase containing Y, Cu, and O. Because Y takes time to diffuse to the particle surfaces, the apparent melting point of this new phase appears at higher temperatures in initial DTA scans than in subsequent scans. Vaporization of the moltenmore » copper-oxide-rich phase at the temperatures studied causes a gradual shift in composition from Y{sub 2}Cu{sub 4}O{sub 5} to the less copper-rich Y{sub 2}Cu{sub 2}O{sub 5} phase. The presence of the Y{sub 2}Cu{sub 2}O{sub 5} phase in CuO-doped 3Y-TZP allows for previous sintering and superplasticity results to be explained.« less

Welding abilities of UFG metals

NASA Astrophysics Data System (ADS)

Morawiński, Łukasz; Chmielewski, Tomasz; Olejnik, Lech; Buffa, Gianluca; Campanella, Davide; Fratini, Livan

2018-05-01

Ultrafine Grained (UFG) metals are characterized by an average grain size of <1 µm and mostly high angle grain boundaries. These materials exhibit exceptional improvements in strength, superplastic behaviour and in some cases enhanced biocompatibility. UFG metals barstock can be fabricated effectively by means of Severe Plastic Deformation (SPD) methods. However, the obtained welded joints with similar properties to the base of UFG material are crucial for the production of finished engineering components. Conventional welding methods based on local melting of the joined edges cannot be used due to the UFG microstructure degradation caused by the heat occurrence in the heat affected zone. Therefore, the possibility of obtaining UFG materials joints with different shearing plane (SP) positions by means of friction welded processes, which do not exceed the melting temperature during the process, should be investigated. The article focuses on the Linear Friction Welding (LFW) method, which belongs to innovative welding processes based on mixing of the friction-heated material in the solid state. LFW is a welding process used to joint bulk components. In the process, the friction forces work due to the high frequency oscillation and the pressure between the specimens is converted in thermal energy. Character and range of recrystallization can be controlled by changing LFW parameters. Experimental study on the welded UFG 1070 aluminum alloy by means of FLW method, indicates the possibility of reducing the UFG structure degradation in the obtained joint. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency.

Deformation of Extruded Titanium Alloys Under Superplastic Conditions

DTIC Science & Technology

1988-07-01

176mm wide with a flange wall 37mm high x 27mm wide and a central web 122mm wide x 18mm thick. Round-bar test pieces aligned parallel to the principal...directions L, T and ST were extrac- ted from the flange and web as shown in Fig 1; gauge length dimensions were 15mm x 5.5mm diameter for the FST test...ares. in the gauge length. Flange Web X 9 NTIS GFA&I v FL Distribut I oc / A es ’- n:ia or Fig I Position of test pieces in extruded section iste i

Technology development status at McDonnell Douglas

NASA Technical Reports Server (NTRS)

Rowe, W. T.

1981-01-01

The significant technology items of the Concorde and the conceptual MCD baseline advanced supersonic transport are compared. The four major improvements are in the areas of range performance, structures (materials), aerodynamics, and in community noise. Presentation charts show aerodynamic efficiency; the reoptimized wing; low scale lift/drag ratio; control systems; structural modeling and analysis; weight and cost comparisons for superplasticity diffusion bonded titanium sandwich structures and for aluminum brazed titanium honeycomb structures; operating cost reduction; suppressor nozzles; noise reduction and range; the bicone inlet; a market summary; environmental issues; high priority items; the titanium wing and fuselage test components; and technology validation.

Numerical analysis of back pressure equal channel angular pressing of an Al-Mg alloy

NASA Astrophysics Data System (ADS)

Comăneci, R.

2017-08-01

Ultrafine grain size provides enhanced mechanical and/or physical properties such as strength and high ductility, superplasticity at relatively low temperatures and high strain rate and better corrosion resistance. Well-known as one of the most promising and effective structure refining method among other severe plastic deformation (SPD) techniques, equal channel angular pressing (ECAP) has been intensively investigated due to spectacular improvements in structure and therefore properties of bulk ultrafine grained/nanostructured materials. A successful ECAP requires surpassing two obstacles: the necessary load level which directly affects tools and a favourable stress distribution so the material withstanding the accumulated strain of repeated deformation. Materials could withstand more passes if a back pressure (BP) is applied. In traditional ECAP, tensile stress along the contact surface between the work piece and the upper wall of the outlet channel leads to crack initiation, while in the presence of BP, a negative (compressive) stress appears during the process balancing the tensile stress. In this study a comparative tridimensional finite element analysis (FEA) is performed to evaluate the flow of an Al-Mg alloy depending on different BP levels and process parameters. The results in terms of load level and strain distribution show the influence of BP on the material behaviour, opening opportunities for industrial applications.

Distribution of nickel after modified nitinol stent implantation in animals

NASA Astrophysics Data System (ADS)

Chepeleva, E.; Sergeevichev, D.; Lotkov, A.; Kashin, O.; Korobeynikov, A.; Kozyr, K.; Baystrukov, V.; Zubarev, D.; Kretov, E.; Pokushalov, E.

2017-09-01

Intravascular stenting of arteries in atherosclerotic lesions is one of the most frequently performed procedures in cardiovascular surgery today. Most stents are made of various stainless-steel alloys and other metals (such as nitinol). Nitinol is a biocompatible, superplastic and corrosion resistant material with an important feature of shape memory. However, the composition of this alloy includes nickel, which shows toxicity to the kidneys, liver, lungs, heart and other organs when it accumulates in the organism. In this research we investigated the nickel content in serum, urine and hair of the laboratory animals after implantation of nitinol stents treated with plasma ionic surface modification by silicon.

Application of powder metallurgy to an advanced-temperature nickel-base alloy, NASA-TRW 6-A

NASA Technical Reports Server (NTRS)

Freche, J. C.; Ashbrook, R. L.; Waters, W. J.

1971-01-01

Bar stock of the NASA-TRW 6-A alloy was made by prealloyed powder techniques and its properties evaluated over a range of temperatures. Room temperature ultimate tensile strength was 1894 MN/sq m (274 500 psi). The as-extruded powder product showed substantial improvements in strength over the cast alloy up to 649 C (1200 F) and superplasticity at 1093 C (2000 F). Both conventional and autoclave heat treatments were applied to the extruded powder product. The conventional heat treatment was effective in increasing rupture life at 649 and 704 C (1200 and 1300 F); the autoclave heat treatment, at 760 and 816 C (1400 and 1500 F).

Sliding inclusions and their applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mura, T.

It is found that when an ellipsoidal inclusion undergoes a shear eigenstrain and the inclusion is free to slip along the interface, the stress field vanishes everywhere in the inclusion and the matrix. It is assumed in the analysis that the inclusion interface cannot sustain any shear traction. There exists a shear deformation which transforms an ellipsoid into the identical ellipsoid without changing its orientation (ellipsoid invariant transformation). Therefore, no resistance for shear deformation is expected. This may be a characteristic of deformation seen in superplasticity alloys and granular materials. The theory is valid even for large deformations when incrementalmore » strains (or strain rates) are considered instead of strains themselves.« less

Superplastic Behaviour of AZ61-F Magnesium Composite Materials

NASA Astrophysics Data System (ADS)

Besterci, Michal; Sülleiová, Katarína; Velgosová, Oksana; Balloková, Beáta; Huang, S.-J.

2017-03-01

Deformation of AZ61-F magnesium alloys with 1 wt % of Al2O3 phase was tested at different temperatures and different strain rates. It was shown that at temperatures 473-523 K and the highest strain rate applied from 1×10-2 s-1 to 1×10-4 s-1, a significant ductility growth was observed. The grain size of 0.6-0.8 μm was reached by severe plastic deformations by means of equal channel angular pressing (ECAP). Secondary Mg17Al12 and Al2O3 phases were identified. Maximum strain was gained at temperature of 473 K and strain rate of 1×10-4 s-1.

Numerical Implementation of Ice Rheology for Europa's Shell

NASA Technical Reports Server (NTRS)

Barr, A. C.; Pappalardo, R. T.

2004-01-01

We present a discussion of approximations to the temperature dependent part of the rheology of ice. We have constructed deformation maps using the superplastic rheology of Goldsby & Kohlstedt and find that the rheologies that control convective flow in the Europa's are likely grain boundary sliding and basal slip for a range of grain sizes 0.1 mm < d < 1 cm. We compare the relative merits of two different approximations to the temperature dependence of viscosity and argue that for temperature ranges appropriate to Europa, implementing the non-Newtonian, lab-derived flow law directly is required to accurately judge the onset of convection in the ice shell and temperature gradient in the near-surface ice.

The effect of sheet processing on the microstructure, tensile, and creep behavior of INCONEL alloy 718

NASA Astrophysics Data System (ADS)

Boehlert, C. J.; Dickmann, D. S.; Eisinger, Ny. N. C.

2006-01-01

The grain size, grain boundary character distribution (GBCD), creep, and tensile behavior of INCONEL alloy 718 (IN 718) were characterized to identify processing-microstructure-property relationships. The alloy was sequentially cold rolled (CR) to 0, 10, 20, 30, 40, 60, and 80 pct followed by annealing at temperatures between 954 °C and 1050 °C and the traditional aging schedule used for this alloy. In addition, this alloy can be superplastically formed (IN 718SPF) to a significantly finer grain size and the corresponding microstructure and mechanical behavior were evaluated. The creep behavior was evaluated in the applied stress (σ a ) range of 300 to 758 MPa and the temperature range of 638 °C to 670 °C. Constant-load tensile creep experiments were used to measure the values of the steady-state creep rate and the consecutive load reduction method was used to determine the values of backstress (σ0). The values for the effective stress exponent and activation energy suggested that the transition between the rate-controlling creep mechanisms was dependent on effective stresses (σ e =σ a σ0) and the transition occurred at σ e ≅ 135 MPa. The 10 to 40 pct CR samples exhibited the greatest 650 °C strength, while IN 718SPF exhibited the greatest room-temperature (RT) tensile strength (>1550 MPa) and ductility (ɛ f >16 pct). After the 954 °C annealing treatment, the 20 pct CR and 30 pct CR microstructures exhibited the most attractive combination of elevated-temperature tensile and creep strength, while the most severely cold-rolled materials exhibited the poorest elevated-temperature properties. After the 1050 °C annealing treatment, the IN 718SPF material exhibited the greatest backstress and best creep resistance. Electron backscattered diffraction was performed to identify the GBCD as a function of CR and annealing. The data indicated that annealing above 1010 °C increased the grain size and resulted in a greater fraction of twin boundaries, which in turn increased the fraction of coincident site lattice boundaries. This result is discussed in light of the potential to grain boundary engineer this alloy.

Microstructural Evolution during Mid-Crustal Shear Zone Thickening and Thinning, Mount Irene Detachment Zone, Fiordland, New Zealand

NASA Astrophysics Data System (ADS)

Negrini, M.; Smith, S. A. F.; Scott, J.; Rooney, J. S.; Demurtas, M.

2016-12-01

Recent work has shown that ductile shear zones experience cyclic variations in stress and strain rate due to, for example, elastic loading from earthquake slip on brittle faults or the presence of rigid particles and asperities within the shear zone. Such non-steady state flow conditions can promote microstructural changes including a decrease in grain sizes followed by a switch in the main deformation mechanisms. Understanding the microstructural changes that occur during non steady-state deformation is therefore critical in evaluating shear zone rheology. The Mount Irene shear zone formed during Cretaceous extension in the middle crust and was active at temperatures of 600°C and pressures of 6 kbar. The shear zone localized in a basal calcite marble layer typically 3-5 m thick containing hundreds of thin (mm-cm) calc-silicate bands that are now parallel to the shear zone boundaries. The lower boundary of the shear zone preserves meter-scale undulations that cause the shear zone to be squeezed in to regions that are <1.5 m thick. The calc-silicate bands act as "flow markers" and allow individual shear zone layers to be traced continuously through thick and thin regions, implying that the mylonites experienced cyclic variations in stress and strain rate. Calc-mylonite samples collected from the same layer close to the base of the shear zone reveal that layer thinning was accompanied by progressive microstructural changes including intense twinning, stretching and flattening of large calcite porphyroclasts as well as the development of interconnected networks of recrystallized calcite aggregates. EBSD analysis shows that the recrystallized aggregates contain polygonal calcite grains with microstructures (e.g. grain quadruple junctions) similar to those reported for neighbor-switching processes associated with grain boundary sliding and superplasticity. Ongoing and future work will utilize samples from across the full thickness of the shear zone to determine key microstructural changes and deformation mechanisms that accommodated shear zone thinning and thickening during non-steady state deformation.

Formation of Gradient Structures in the Zone of Joining a Deformable Nickel Alloy and a Single-Crystal Intermetallic Alloy during Thermodiffusion Pressure Welding and Subsequent Heat Treatment

NASA Astrophysics Data System (ADS)

Povarova, K. B.; Valitov, V. A.; Drozdov, A. A.; Bazyleva, O. A.; Galieva, E. V.; Arginbaeva, E. G.

2018-01-01

The possibility of formation of a high-quality solid-phase joint of an Ni3Al-based single-crystal intermetallic VKNA-25 blade alloy with a high-temperature deformable EP975 disk alloy by pressure welding is studied to create high-performance one-piece blisk unit for the next-generation aviation gas turbine engines and to decrease the unit mass. The influence of the conditions of thermodiffusion pressure welding under the hightemperature superplasticity of the disk alloy and the influence of heat treatment of welded joints on the gradient structures in the welded joint zone and the structure at the periphery of the welded samples are investigated.

A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced Materials

NASA Technical Reports Server (NTRS)

Garmestai, H.; Harris, K.; Lourenco, L.

1997-01-01

Representation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.

Grain dynamics and plastic properties of highly refined materials

NASA Astrophysics Data System (ADS)

Lagos, Miguel; Retamal, César

2010-12-01

It has been shown that a grain boundary may undergo two competing classes of elastic instability when the in-plane shear stress exceeds the proper critical values. It may buckle acquiring a sinusoidal shape or may develop a periodic series of fissures, separating bands with a sigmoidal profile. The two instabilities lead to grain sliding, but the corresponding expressions relating the relative velocity between adjacent grains with stress do differ. The plastic properties for small strains were calculated for the two force laws, which we called force models A and B. A comparison of the theoretical results with published experimental data shows that model A, while giving predictions within the experimental uncertainties for a series of superplastic aluminium and titanium alloys, fails for Avesta 2304 steel. However, excellent results are obtained when model B is applied for this steel.

Adsorption as a method of doping 3-mol%-yttria-stabilized zirconia powder with copper oxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seidensticker, J.R.; Mayo, M.J.; Osseo-Asare, K.

The adsorption behavior of Cu[sup 2+] on 3-mol%-yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) powder was studied. There is a window of pH values (10 < pH < 11) where adsorption may be used as a method of doping 3Y-TZP with Cu[sup 2+]. The maximum mole percent of the CuO additions is determined by the specific surface area of the 3Y-TZP powder; a powder with a specific surface area of 16.1 m[sup 2]/g is limited to about 1 mol% CuO. Compacts made from powders doped with CuO using this method exhibited an enhancement in superplasticity comparable to that observed in other studiesmore » using samples doped with CuO by attrition milling.« less

Can grain size sensitive creep lubricate faults during earthquake propagation?

NASA Astrophysics Data System (ADS)

De Paola, N.; Holdsworth, R.; Viti, C.; Collettini, C.; Bullock, R. J.; Faoro, I.

2014-12-01

In the shallow portion of crustal fault zones, fracturing and cataclasis are thought to be the dominant processes during earthquake propagation. In the lower crust/upper mantle, viscous flow is inferred to facilitate aseismic creep along shear zones. Recent studies show that slip zones (SZs), in natural and experimental carbonate seismic faults, are made of nanograins with a polygonal texture, a microstructure consistent with deformation by grain boundary sliding (GBS) mechanisms. Friction experiments performed on calcite fine-grained gouges, at speed v = 1 ms-1, normal stress sn = 18 MPa, displacements d = 0.009-1.46 m, and room temperature and humidity, show a four stage-evolution of the fault strength: SI) attainment of initial value, f = 0.67; SII) increase up to peak value f = 0.82; SIII) sudden decrease to low steady-state value, f = 0.18; and SIV) sudden increase to final value, f = 0.44, during sample deceleration. Samples recovered at the end of each displacement-controlled experiments (Stages I-IV) show the following microstructures evolution of the SZ material, which is: SI) poorly consolidated, and made of fine-grained (1 < D < 5 microns), angular clasts formed by brittle fracturing and cataclasis; SII) cohesive, and made of larger clasts of calcite (D ≈ 1 microns), exhibiting a high density of free dislocations and hosting subgrains (D ≤ 200 nm), dispersed within calcite nanograins. SIII) made of nanograin aggregates exhibiting polygonal grain boundaries, and 120° triple junctions between equiaxial grains. The grains display no preferred elongation, no crystal preferred orientation and low free dislocation densities, possibly due to high temperature (> 900 C) GBS creep deformation. Our microstructural observations suggest that GBS mechanisms can operate in geological materials deformed at high strain rates along frictionally heated seismogenic slip surfaces. The observed microstructures in experimental slip zones are strikingly similar to those predicted by theoretical studies, and to those observed during experiments on metals and fine-grained carbonates deformed at T > 900 °C, where superplastic behaviour due to GBS has been inferred. A regime of frictionally-induced GBS could thus account for the dynamic weakening of carbonate faults during earthquake propagation in nature.

Effects of Hot Rolling on Low-Cycle Fatigue Properties of Zn-22 wt.% Al Alloy at Room Temperature

NASA Astrophysics Data System (ADS)

Dong, X. H.; Cao, Q. D.; Ma, S. J.; Han, S. H.; Tang, W.; Zhang, X. P.

2016-09-01

The effects of the reduction ratio (RR) on the low-cycle fatigue (LCF) properties of the Zn-22 wt.% Al (Zn-22Al) alloy were investigated. Various grain sizes from 0.68 to 1.13 μm were obtained by controlled RRs. Tensile and LCF tests were carried out at room temperature. Superplasticity and cyclic softening were observed. Strength and ductility of the rolled Zn-22Al alloy increased with the RR, owing to the decrease in its grain size. The RR did not affect the cyclic softening behavior of the alloy. The fatigue life of the alloy decreased with increasing strain amplitude, while the fatigue life first decreased and then increased with increasing RR. The longest fatigue life was observed for the alloy rolled at a RR of 60%. A bilinear Coffin-Manson relationship was observed to hold true for this alloy.

Slip-activated surface creep with room-temperature super-elongation in metallic nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Li; Sansoz, Frederic; He, Yang

2016-11-28

Atom diffusion assisted by surfaces or interfaces (e.g. Coble creep) has been known to be the origin of large creep rates and superplastic softening in nanosized crystals at low temperature. By contrast, source-limited crystal slip in defect-free nanostructures engenders important strengths, but also premature plastic instability and low ductility. Here, using in-situ transmission electron microscopy, we report a slip-activated surface creep mechanism that suppresses the tendency towards plastic instability without compromising the strength, resulting in ultra-large room-temperature plasticity in face-centered-cubic silver nanocrystals. This phenomenon is shown experimentally and theoretically to prevail over a material-dependent range of diameters where surface dislocationmore » nucleation becomes a stimulus to diffusional creep. This work provides new fundamental insight into coupled diffusive-displacive deformation mechanisms maximizing ductility and strength simultaneously in nanoscale materials.« less

Directional solidification of eutectic composites in space environment

NASA Technical Reports Server (NTRS)

Yue, A. S.

1972-01-01

The Ni-Ni3Ta eutectic and a nickel-base alloy containing 30 wt pct Ta were solidified unidirectionally in an electron beam floating zone melting apparatus. It was found that the volume fraction of the Ni3Ta phase in the Ni-Ni3Ta eutectic mixture was increased from 7.6 to 36 volume pct in agreement with the theory as predicted. Tensile properties of the randomly solidified and unidirectionally solidified Ni-Ni3Ta eutectic were determined as function of solidification rate and temperature. It was found that the ultimate tensile strength decreased as both the test temperature and solidification rate increased. An elongation of 40 pct was obtained for a nickelbase alloy containing 30 wt at room temperature. This unusually large elongation was attributed to the superplastic behavior of the alloy. The critical currents versus the external fields at 2.5, 3.0, 3.5 and 4.2 deg for the unidirectionally solidified Pb-Sn eutectic were measured. The values of critical fields at zero critical currents were obtained by extrapolation.

Recent progress of tungsten R&D for fusion application in Japan

NASA Astrophysics Data System (ADS)

Ueda, Y.; Lee, H. T.; Ohno, N.; Kajita, S.; Kimura, A.; Kasada, R.; Nagasaka, T.; Hatano, Y.; Hasegawa, A.; Kurishita, H.; Oya, Y.

2011-12-01

The status of ongoing research projects of tungsten R&D in Japan is summarized in this paper. For tungsten material development, a new improved fabrication technique, the so-called superplasticity-based microstructural modification, is described. This technique successfully improved fracture strength and ductility at room temperature. Recent results on vacuum plasma spray W coating and W brazing on ferritic steels and vanadium alloys are explained. Feasibility of these techniques for the manufacture of the blanket is successfully demonstrated. The latest findings on the effect of neutron damage in tungsten on T retention and on the change in mechanical and electrical properties are described. Retention characteristics for neutron-damaged W were different compared to those for ion-damaged W. Upon neutron irradiation, tungsten alloys containing transmutation elements of W (Re and Os) show changes in properties that are different compared with those shown by pure W. The effects of mixed plasma exposure (D/He/C) are described. Both D/He and D/C mixed ion irradiations significantly affect ion-driven permeation in W. He bubble dynamics play a key role in nano-structure formation on the W surface.

Multifunctional Beta Ti Alloy with Improved Specific Strength

NASA Astrophysics Data System (ADS)

Park, Chan Hee; Hong, Jae-Keun; Lee, Sang Won; Yeom, Jong-Taek

2017-12-01

Gum metals feature properties such as ultrahigh strength, ultralow elastic modulus, superelasticity, and superplasticity. They are composed of elements from Groups 4 and 5 of the periodic table and exist when the valance electron concentration (\\overline{e/a}) is 4.24; the bond order (\\overline{Bo}) is 2.87; and the "d" electron-orbital energy level (\\overline{Md}) is 2.45 eV. Typical compositions include Ti-23Nb-2Zr-0.7Ta-O and Ti-12Ta-9Nb-6Zr-3 V-O, which contain large amounts of heavy Group-5 elements such as Nb and Ta. In the present study, to improve the specific strength of a multifunctional beta Ti alloy, three alloys (Ti-20Nb-5Zr-1Fe-O, Ti-12Zr-10Mo-4Nb-O, and Ti-24Zr-9Cr-3Mo-O) were designed by satisfying the above three requirements while adding Fe, Mo, and Cr, which are not only lightweight but also have strong hardening effects. Microstructural and mechanical property analyses revealed that Ti-20Nb-5Zr-1Fe-O has a 25% higher specific strength than gum metal while maintaining an ultralow elastic modulus.

Low-Temperature Friction-Stir Welding of 2024 Aluminum

NASA Technical Reports Server (NTRS)

Benavides, S.; Li, Y.; Murr, L. E.; Brown, D.; McClure, J. C.

1998-01-01

Solid state friction-stir welding (FSW) has been demonstrated to involve dynamic recrystallization producing ultra-fine, equiaxed grain structures to facilitate superplastic deformation as the welding or joining mechanism. However, the average residual, equiaxed, grain size in the weld zone has ranged from roughly 0.5 micron to slightly more than 10 micron, and the larger weld zone grain sizes have been characterized as residual or static grain growth as a consequence of the temperatures in the weld zone (where center-line temperatures in the FSW of 6061 Al have been shown to be as high as 480C or -0.8 T(sub M) where T(sub M) is the absolute melting temperature)). In addition, the average residual weld zone grain size has been observed to increase near the top of the weld, and to decrease with distance on either side of the weld-zone centerline, an d this corresponds roughly to temperature variations within the weld zone. The residual grain size also generally decreases with decreasing FSW tool rotation speed. These observations are consistent with the general rules for recrystallization where the recrystallized grain size decreases with increasing strain (or deformation) at constant strain rate, or with increasing strain-rate, or with increasing strain rate at constant strain; especially at lower ambient temperatures, (or annealing temperatures). Since the recrystallization temperature also decreases with increasing strain rate, the FSW process is somewhat complicated because the ambient temperature, the frictional heating fraction, and the adiabatic heating fraction )proportional to the product of strain and strain-rate) will all influence both the recrystallization and growth within the FSW zone. Significantly reducing the ambient temperature of the base metal or work pieces to be welded would be expected to reduce the residual weld-zone grain size. The practical consequences of this temperature reduction would be the achievement of low temperature welding. This study compares the residual grain sizes and microstructures in 2024 Al friction-stir welded at room temperature (about 30C and low temperature (-30C).

Kinetic theory for the formation of diamond nanothreads with desired configurations: a strain-temperature controlled phase diagram.

PubMed

Gao, Junfeng; Zhang, Gang; Yakobson, Boris I; Zhang, Yong-Wei

2018-05-24

Diamond nanothreads (DNTs) are a brand-new one-dimensional carbon nanomaterial that was synthesized recently by compressing benzene. Compared with sp2 carbon nanotubes, DNTs may possess a much higher interfacial load-transfer ability. However, previous studies have shown that the mechanical properties of DNTs are highly sensitive to the composition of Stone-Wales (SW) transformed sites. Up to now, it remained unclear what roles SWs play in the structure stability and how to engineer its molecular structure for novel mechanical properties. Using ab initio calculations, here we show that the most stable structure of a DNT is composed of alternative SW and hydrogenated carbon nanotube (3,0) units, suggesting that SW plays an essential role in stabilizing DNT. Interestingly, we found that the SW transition barrier is a nearly linear function of the applied strain, enabling strain engineering of its molecular structure. To do so, we propose a strain-temperature-stretching rate phase diagram to guide the construction of desired molecular structures to achieve superplastic behavior of DNTs. Our findings not only enrich our understanding of this novel carbon material, but also provide a strategy to control its structural and mechanical properties for novel applications, such as energy absorption, energy storage and materials reinforcement.

Time-lapse nanoscopy of friction in the non-Amontons and non-Coulomb regime.

PubMed

Ishida, Tadashi; Sato, Takaaki; Ishikawa, Takahiro; Oguma, Masatsugu; Itamura, Noriaki; Goda, Keisuke; Sasaki, Naruo; Fujita, Hiroyuki

2015-03-11

Originally discovered by Leonard da Vinci in the 15th century, the force of friction is directly proportional to the applied load (known as Amontons' first law of friction). Furthermore, kinetic friction is independent of the sliding speed (known as Coulomb's law of friction). These empirical laws break down at high normal pressure (due to plastic deformation) and low sliding speed (in the transition regime between static friction and kinetic friction). An important example of this phenomenon is friction between the asperities of tectonic plates on the Earth. Despite its significance, little is known about the detailed mechanism of friction in this regime due to the lack of experimental methods. Here we demonstrate in situ time-lapse nanoscopy of friction between asperities sliding at ultralow speed (∼0.01 nm/s) under high normal pressure (∼GPa). This is made possible by compressing and rubbing a pair of nanometer-scale crystalline silicon anvils with electrostatic microactuators and monitoring its dynamical evolution with a transmission electron microscope. Our analysis of the time-lapse movie indicates that superplastic behavior is induced by decrystallization, plastic deformation, and atomic diffusion at the asperity-asperity interface. The results hold great promise for a better understanding of quasi-static friction under high pressure for geoscience, materials science, and nanotechnology.

Design of cryogenic tanks for launch vehicles

NASA Technical Reports Server (NTRS)

Copper, Charles; Pilkey, Walter D.; Haviland, John K.

1990-01-01

During the period since January 1990, work was concentrated on the problem of the buckling of the structure of an ALS (advanced launch systems) tank during the boost phase. The primary problem was to analyze a proposed hat stringer made by superplastic forming, and to compare it with an integrally stiffened stringer design. A secondary objective was to determine whether structural rings having the identical section to the stringers will provide adequate support against overall buckling. All of the analytical work was carried out with the TESTBED program on the CONVEX computer, using PATRAN programs to create models. Analyses of skin/stringer combinations have shown that the proposed stringer design is an adequate substitute for the integrally stiffened stringer. Using a highly refined mesh to represent the corrugations in the vertical webs of the hat stringers, effective values were obtained for cross-sectional area, moment of inertia, centroid height, and torsional constant. Not only can these values be used for comparison with experimental values, but they can also be used for beams to replace the stringers and frames in analytical models of complete sections of tank. The same highly refined model was used to represent a section of skin reinforced by a stringer and a ring segment in the configuration of a cross. It was intended that this would provide a baseline buckling analysis representing a basic mode, however, the analysis proved to be beyond the scope of the CONVEX computer. One quarter of this model was analyzed, however, to provide information on buckling between the spot welds. Models of large sections of the tank structure were made, using beam elements to model the stringers and frames. In order to represent the stiffening effects of pressure, stresses and deflections under pressure should first be obtained, and then the buckling analysis should be made on the structure so deflected. So far, uncharacteristic deflections under pressure were obtained from the TESTBED program using two types of structural elements. Similar results were obtained using the ANSYS program on a mainframe computer, although two finite element programs on microcomputers have yielded realistic results.

A continuum dislocation dynamics framework for plasticity of polycrystalline materials

NASA Astrophysics Data System (ADS)

Askari, Hesam Aldin

The objective of this research is to investigate the mechanical response of polycrystals in different settings to identify the mechanisms that give rise to specific response observed in the deformation process. Particularly the large deformation of magnesium alloys and yield properties of copper in small scales are investigated. We develop a continuum dislocation dynamics framework based on dislocation mechanisms and interaction laws and implement this formulation in a viscoplastic self-consistent scheme to obtain the mechanical response in a polycrystalline system. The versatility of this method allows various applications in the study of problems involving large deformation, study of microstructure and its evolution, superplasticity, study of size effect in polycrystals and stochastic plasticity. The findings from the numerical solution are compared to the experimental results to validate the simulation results. We apply this framework to study the deformation mechanisms in magnesium alloys at moderate to fast strain rates and room temperature to 450 °C. Experiments for the same range of strain rates and temperatures were carried out to obtain the mechanical and material properties, and to compare with the numerical results. The numerical approach for magnesium is divided into four main steps; 1) room temperature unidirectional loading 2) high temperature deformation without grain boundary sliding 3) high temperature with grain boundary sliding mechanism 4) room temperature cyclic loading. We demonstrate the capability of our modeling approach in prediction of mechanical properties and texture evolution and discuss the improvement obtained by using the continuum dislocation dynamics method. The framework was also applied to nano-sized copper polycrystals to study the yield properties at small scales and address the observed yield scatter. By combining our developed method with a Monte Carlo simulation approach, the stochastic plasticity at small length scales was studied and the sources of the uncertainty in the polycrystalline structure are discussed. Our results suggest that the stochastic response is mainly because of a) stochastic plasticity due to dislocation substructure inside crystals and b) the microstructure of the polycrystalline material. The extent of the uncertainty is correlated to the "effective cell length" in the sampling procedure whether using simulations and experimental approach.

Effects of Processing Parameters on the Forming Quality of C-Shaped Thermosetting Composite Laminates in Hot Diaphragm Forming Process

NASA Astrophysics Data System (ADS)

Bian, X. X.; Gu, Y. Z.; Sun, J.; Li, M.; Liu, W. P.; Zhang, Z. G.

2013-10-01

In this study, the effects of processing temperature and vacuum applying rate on the forming quality of C-shaped carbon fiber reinforced epoxy resin matrix composite laminates during hot diaphragm forming process were investigated. C-shaped prepreg preforms were produced using a home-made hot diaphragm forming equipment. The thickness variations of the preforms and the manufacturing defects after diaphragm forming process, including fiber wrinkling and voids, were evaluated to understand the forming mechanism. Furthermore, both interlaminar slipping friction and compaction behavior of the prepreg stacks were experimentally analyzed for showing the importance of the processing parameters. In addition, autoclave processing was used to cure the C-shaped preforms to investigate the changes of the defects before and after cure process. The results show that the C-shaped prepreg preforms with good forming quality can be achieved through increasing processing temperature and reducing vacuum applying rate, which obviously promote prepreg interlaminar slipping process. The process temperature and forming rate in hot diaphragm forming process strongly influence prepreg interply frictional force, and the maximum interlaminar frictional force can be taken as a key parameter for processing parameter optimization. Autoclave process is effective in eliminating voids in the preforms and can alleviate fiber wrinkles to a certain extent.

Effect of multiple forming tools on geometrical and mechanical properties in incremental sheet forming

NASA Astrophysics Data System (ADS)

Wernicke, S.; Dang, T.; Gies, S.; Tekkaya, A. E.

2018-05-01

The tendency to a higher variety of products requires economical manufacturing processes suitable for the production of prototypes and small batches. In the case of complex hollow-shaped parts, single point incremental forming (SPIF) represents a highly flexible process. The flexibility of this process comes along with a very long process time. To decrease the process time, a new incremental forming approach with multiple forming tools is investigated. The influence of two incremental forming tools on the resulting mechanical and geometrical component properties compared to SPIF is presented. Sheets made of EN AW-1050A were formed to frustums of a pyramid using different tool-path strategies. Furthermore, several variations of the tool-path strategy are analyzed. A time saving between 40% and 60% was observed depending on the tool-path and the radii of the forming tools while the mechanical properties remained unchanged. This knowledge can increase the cost efficiency of incremental forming processes.

Data-based control of a multi-step forming process

NASA Astrophysics Data System (ADS)

Schulte, R.; Frey, P.; Hildenbrand, P.; Vogel, M.; Betz, C.; Lechner, M.; Merklein, M.

2017-09-01

The fourth industrial revolution represents a new stage in the organization and management of the entire value chain. However, concerning the field of forming technology, the fourth industrial revolution has only arrived gradually until now. In order to make a valuable contribution to the digital factory the controlling of a multistage forming process was investigated. Within the framework of the investigation, an abstracted and transferable model is used to outline which data have to be collected, how an interface between the different forming machines can be designed tangible and which control tasks must be fulfilled. The goal of this investigation was to control the subsequent process step based on the data recorded in the first step. The investigated process chain links various metal forming processes, which are typical elements of a multi-step forming process. Data recorded in the first step of the process chain is analyzed and processed for an improved process control of the subsequent process. On the basis of the gained scientific knowledge, it is possible to make forming operations more robust and at the same time more flexible, and thus create the fundament for linking various production processes in an efficient way.

Process development and tooling design for intrinsic hybrid composites

NASA Astrophysics Data System (ADS)

Riemer, M.; Müller, R.; Drossel, W. G.; Landgrebe, D.

2017-09-01

Hybrid parts, which combine the advantages of different material classes, are moving into the focus of lightweight applications. This development is amplified by their high potential for usage in the field of crash relevant structures. By the current state of the art, hybrid parts are mainly made in separate, subsequent forming and joining processes. By using the concept of an intrinsic hybrid, the shaping of the part and the joining of the different materials are performed in a single process step for shortening the overall processing time and thereby the manufacturing costs. The investigated hybrid part is made from continuous fibre reinforced plastic (FRP), in which a metallic reinforcement structure is integrated. The connection between these layered components is realized by a combination of adhesive bonding and a geometrical form fit. The form fit elements are intrinsically generated during the forming process. This contribution regards the development of the forming process and the design of the forming tool for the single step production of a hybrid part. To this end a forming tool, which combines the thermo-forming and the metal forming process, is developed. The main challenge by designing the tool is the temperature management of the tool elements for the variothermal forming process. The process parameters are determined in basic tests and finite element (FE) simulation studies. On the basis of these investigations a control concept for the steering of the motion axes and the tool temperature is developed. Forming tests are carried out with the developed tool and the manufactured parts are analysed by computer assisted tomography (CT) scans.

Development of Replacements for Phoscoating Used in Forging, Extrusion and Metal Forming Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerry Barnett

2003-03-01

Many forging, extrusion, heading and other metal forming processes use graphite-based lubricants, phosphate coatings, and other potentially hazardous or harmful substances to improve the tribology of the metal forming process. The application of phosphate-based coatings has long been studied to determine if other synthetic ''clean'' lubricants could provide the same degree of protection afforded by phoscoatings and its formulations. So far, none meets the cost and performance objectives provided by phoscoatings as a general aid to the metal forming industry. In as much as phoscoatings and graphite have replaced lead-based lubricants, the metal forming industry has had previous experience withmore » a legislated requirement to change processes. However, without a proactive approach to phoscoating replacement, many metal forming processes could find themselves without a cost effective tribology material necessary for the metal forming process« less

Radial-rotation profile forming: A new processing technology of incremental sheet metal forming

NASA Astrophysics Data System (ADS)

Laue, Robert; Härtel, Sebastian; Awiszus, Birgit

2018-05-01

Incremental forming processes (i.e., spinning) of sheet metal blanks into cylindrical cups are suitable for lower lot sizes. The produced cups were frequently used as preforms to produce workpieces in further forming steps with additional functions like profiled hollow parts [1]. The incremental forming process radial-rotation profile forming has been developed to enable the production of profiled hollow parts with low sheet thinning and good geometrical accuracy. The two principal forming steps are the production of the preform by rotational swing-folding [2] and the subsequent radial profiling of the hollow part in one clamping position. The rotational swing-folding process is based on a combination of conventional spinning and swing-folding. Therefore, a round blank rotates on a profiled mandrel and due to the swinging of a cylindrical forming tool, the blank is formed to a cup with low sheet thinning. In addition, thickening results at the edge of the blank and wrinkling occurs. However, the wrinkles are formed into the indentation of the profiled mandrel and can be reshaped as an advantage in the second process step, the radial profiling. Due to the rotation and continuous radial feed of a profiled forming tool to the profiled mandrel, the axial profile is formed in the second process step. Because of the minor relative movement in axial direction between tool and blank, low sheet thinning occurs. This is an advantage of the principle of the process.

Global form and motion processing in healthy ageing.

PubMed

Agnew, Hannah C; Phillips, Louise H; Pilz, Karin S

2016-05-01

The ability to perceive biological motion has been shown to deteriorate with age, and it is assumed that older adults rely more on the global form than local motion information when processing point-light walkers. Further, it has been suggested that biological motion processing in ageing is related to a form-based global processing bias. Here, we investigated the relationship between older adults' preference for form information when processing point-light actions and an age-related form-based global processing bias. In a first task, we asked older (>60years) and younger adults (19-23years) to sequentially match three different point-light actions; normal actions that contained local motion and global form information, scrambled actions that contained primarily local motion information, and random-position actions that contained primarily global form information. Both age groups overall performed above chance in all three conditions, and were more accurate for actions that contained global form information. For random-position actions, older adults were less accurate than younger adults but there was no age-difference for normal or scrambled actions. These results indicate that both age groups rely more on global form than local motion to match point-light actions, but can use local motion on its own to match point-light actions. In a second task, we investigated form-based global processing biases using the Navon task. In general, participants were better at discriminating the local letters but faster at discriminating global letters. Correlations showed that there was no significant linear relationship between performance in the Navon task and biological motion processing, which suggests that processing biases in form- and motion-based tasks are unrelated. Copyright © 2016. Published by Elsevier B.V.

JPRS Report, Science & Technology, Japan, High Temperature Materials

DTIC Science & Technology

1990-11-09

3 This restriction is heavy. The inconvenience that the material powder of the imido thermal composition method, for example, which shows the best...procedures, system composition , features of formability, and forming characteristic of forming samples using alumina material will be made. 2...Osmotic V Process Forming System 2.1 System Composition of Process A system block diagram of the process is shown in Figure 1. The V process forming system

Effects of Vibrations on Metal Forming Process: Analytical Approach and Finite Element Simulations

NASA Astrophysics Data System (ADS)

Armaghan, Khan; Christophe, Giraud-Audine; Gabriel, Abba; Régis, Bigot

2011-01-01

Vibration assisted forming is one of the most recent and beneficial technique used to improve forming process. Effects of vibration on metal forming processes can be attributed to two causes. First, the volume effect links lowering of yield stress with the influence of vibration on the dislocation movement. Second, the surface effect explains lowering of the effective coefficient of friction by periodic reduction contact area. This work is related to vibration assisted forming process in viscoplastic domain. Impact of change in vibration waveform has been analyzed. For this purpose, two analytical models have been developed for two different types of vibration waveforms (sinusoidal and triangular). These models were developed on the basis of Slice method that is used to find out the required forming force for the process. Final relationships show that application of triangular waveform in forming process is more beneficial as compare to sinusoidal vibrations in terms of reduced forming force. Finite Element Method (FEM) based simulations were performed using Forge2008®and these confirmed the results of analytical models. The ratio of vibration speed to upper die speed is a critical factor in the reduction of the forming force.

Interactions between motion and form processing in the human visual system.

PubMed

Mather, George; Pavan, Andrea; Bellacosa Marotti, Rosilari; Campana, Gianluca; Casco, Clara

2013-01-01

The predominant view of motion and form processing in the human visual system assumes that these two attributes are handled by separate and independent modules. Motion processing involves filtering by direction-selective sensors, followed by integration to solve the aperture problem. Form processing involves filtering by orientation-selective and size-selective receptive fields, followed by integration to encode object shape. It has long been known that motion signals can influence form processing in the well-known Gestalt principle of common fate; texture elements which share a common motion property are grouped into a single contour or texture region. However, recent research in psychophysics and neuroscience indicates that the influence of form signals on motion processing is more extensive than previously thought. First, the salience and apparent direction of moving lines depends on how the local orientation and direction of motion combine to match the receptive field properties of motion-selective neurons. Second, orientation signals generated by "motion-streaks" influence motion processing; motion sensitivity, apparent direction and adaptation are affected by simultaneously present orientation signals. Third, form signals generated by human body shape influence biological motion processing, as revealed by studies using point-light motion stimuli. Thus, form-motion integration seems to occur at several different levels of cortical processing, from V1 to STS.

Interactions between motion and form processing in the human visual system

PubMed Central

Mather, George; Pavan, Andrea; Bellacosa Marotti, Rosilari; Campana, Gianluca; Casco, Clara

2013-01-01

The predominant view of motion and form processing in the human visual system assumes that these two attributes are handled by separate and independent modules. Motion processing involves filtering by direction-selective sensors, followed by integration to solve the aperture problem. Form processing involves filtering by orientation-selective and size-selective receptive fields, followed by integration to encode object shape. It has long been known that motion signals can influence form processing in the well-known Gestalt principle of common fate; texture elements which share a common motion property are grouped into a single contour or texture region. However, recent research in psychophysics and neuroscience indicates that the influence of form signals on motion processing is more extensive than previously thought. First, the salience and apparent direction of moving lines depends on how the local orientation and direction of motion combine to match the receptive field properties of motion-selective neurons. Second, orientation signals generated by “motion-streaks” influence motion processing; motion sensitivity, apparent direction and adaptation are affected by simultaneously present orientation signals. Third, form signals generated by human body shape influence biological motion processing, as revealed by studies using point-light motion stimuli. Thus, form-motion integration seems to occur at several different levels of cortical processing, from V1 to STS. PMID:23730286

Fabricating solar cells with silicon nanoparticles

DOEpatents

Loscutoff, Paul; Molesa, Steve; Kim, Taeseok

2014-09-02

A laser contact process is employed to form contact holes to emitters of a solar cell. Doped silicon nanoparticles are formed over a substrate of the solar cell. The surface of individual or clusters of silicon nanoparticles is coated with a nanoparticle passivation film. Contact holes to emitters of the solar cell are formed by impinging a laser beam on the passivated silicon nanoparticles. For example, the laser contact process may be a laser ablation process. In that case, the emitters may be formed by diffusing dopants from the silicon nanoparticles prior to forming the contact holes to the emitters. As another example, the laser contact process may be a laser melting process whereby portions of the silicon nanoparticles are melted to form the emitters and contact holes to the emitters.

Microstructural characteristics of plasma sprayed nanostructured partially stabilized zirconia

NASA Astrophysics Data System (ADS)

Lima, Rogerio Soares

Thermal barrier coatings have been extensively applied in the aerospace industry in turbines and rocket engines as an insulation system. Partially stabilized zirconia, due to its high thermal stability and low thermal conductivity at high temperatures has been traditionally employed as the ceramic element of the thermal barrier coating system. Different approaches have been taken in order to improve the performance of these coatings. Nanostructured materials are promising an interesting future in the beginning of the 21st century. Due to its enhanced strain to failure and superplasticity new applications may be accomplished or the limits of materials utilization may be placed at higher levels. Single nanostructured particles can not be thermal sprayed by conventional thermal spray equipment. Due to its low mass, they would be deviated to the periphery of the thermal spray jet. To overcome this characteristic, single nanostructured particles were successively agglomerated into large microscopic particles, with particle size distribution similar to the conventional feedstocks for thermal spray equipment. Agglomerated nanostructured particles of partially stabilized zirconia were plasma sprayed in air with different spray parameters. According to traditional thermal spray procedure, the feedstock has to be melted in the thermal spray jet in order to achieve the necessary conditions for adhesion and cohesion on the substrate. Due to the nature of the nanostructured particles, a new step has to be taken in the thermal spray processing; particle melting has to be avoided in order to preserve the feedstock nanostructure in the coating overall microstructure. In this work, the adhesion/cohesion system of nanostructured coatings is investigated and clarified. A percentage of molten particles will retain and hold the non-molten agglomerated nanostructured particles in the coating overall microstructure. Controlling the spray parameters it was possible to produce coatings with different levels of non-molten particles in the coating microstructure; from 25 to 50%. The presence of non-molten and molten phases in the coating microstructure, results in an unique mechanical behavior. The nanostructured coatings present a bimodal distribution with respect to the mechanical properties; each mode has origin from one of the phases. The phases were carefully mapped via scanning electron microscopy and microhardness measurements. These results enabled us to create a model for mechanical properties prediction. This finding is considered one of the most important achievements of this work.

High temperature deformation of Vitreloy bulk metallic glasses and their composite

NASA Astrophysics Data System (ADS)

Tao, Min

A complete understanding of the deformation mechanisms of BMGs and their composites requires investigation of the microstructural changes and their interplay with the mechanical behavior. In this dissertation, the deformation mechanisms of a series of Vitreloy glasses and their composites are experimentally investigated over a wide range of strain rates and temperatures, with focus on the supercooled liquid regime, by combining uniaxial mechanical testing with calorimetric and microscopic examinations. Various theories of deformation of metallic glasses and the composites are examined in light of the experimental data. A comparative structural relaxation study was performed on two closely related Vitreloy alloys, Zr41.2Ti13.8Cu12.5Ni 10Be22.5 (Vit 1) and Zr46.7Ti8.3Cu 7.5Ni10Be27.5 (Vit 4). Differential scanning calorimetric studies on the specimens deformed in compression at constant-strain-rate in supercooled liquid regime showed that mechanical loading accelerated the spinodal phase separation and nanocrystallization process in Vit 1, while the relaxation in Vit 4 featured local chemical composition fluctuation accompanied by annealing out of free volume. The effect of the structural relaxation on their mechanical behavior was further studied via single and multiple jump-in-strain-rate tests. The deformation and viscosity of a new Vitreloy alloy were characterized using uniaxial compression tests in its supercooled liquid regime. A new theoretical model named Cooperative Shear Model, which correlates the evolution of the macroscopic mechanical/thermal variables such as shear modulus and viscosity with the configurational energies of atom clusters in an amorphous alloy, was critically examined in this investigation. The model was successful in predicting the Newtonian and non-Newtonian viscosities of the material, as well as the shear moduli of the deformed specimens, in a self-consistent manner. The plastic flow of an in-situ metallic glass composite, beta-Vitreloy, was investigated under uniaxial compression in its supercooled liquid regime and at various strain rates (10-4 ˜ 10-1 s-1). The composite, with ˜ 25% volume fraction of crystalline beta-phase dendrites exhibited superplastic behavior similar to that of amorphous Vit 1. Significant strain hardening was observed when the material was deformed at high temperatures and low strain rates. A dual-phase composite model was employed in finite element simulations to understand the effect of the composite microstructure on its mechanical behavior.

Hot granules medium pressure forming process of AA7075 conical parts

NASA Astrophysics Data System (ADS)

Dong, Guojiang; Zhao, Changcai; Peng, Yaxin; Li, Ying

2015-05-01

High strength aluminum alloy plate has a low elongation at room temperature, which leads to the forming of its components need a high temperature. Liquid or gas is used as the pressure-transfer medium in the existing flexible mould forming process, the heat resistance of the medium and pressurizing device makes the application of aluminum alloy plate thermoforming restricted. To solve this problem, the existing medium is replaced by the heat-resisting solid granules and the general pressure equipments are applied. Based on the pressure-transfer performance test of the solid granules medium, the feasibility that the assumption of the extended Drucker-Prager linear model can be used in the finite element analysis is proved. The constitutive equation, the yield function and the theoretical forming limit diagram(FLD) of AA7075 sheet are established. Through the finite element numerical simulation of hot granules medium pressure forming(HGMF) process, not only the influence laws of the process parameters, such as forming temperature, the blank-holder gap and the diameter of the slab, on sheet metal forming performance are discussed, but also the broken area of the forming process is analyzed and predicted, which are coincided with the technological test. The conical part whose half cone angle is 15° and relative height H/d 0 is 0.57, is formed in one process at 250°C. The HGMF process solves the problems of loading and seal in the existing flexible mould forming process and provides a novel technology for thermoforming of light alloy plate, such as magnesium alloy, aluminium alloy and titanium alloy.

A Risk-Based Strategy for Evaluating Mitigation Options for Process-Formed Compounds in Food: Workshop Proceedings.

PubMed

Hanlon, Paul; Brorby, Gregory P; Krishan, Mansi

2016-05-01

Processing (eg, cooking, grinding, drying) has changed the composition of food throughout the course of human history; however, awareness of process-formed compounds, and the potential need to mitigate exposure to those compounds, is a relatively recent phenomenon. In May 2015, the North American Branch of the International Life Sciences Institute (ILSI North America) Technical Committee on Food and Chemical Safety held a workshop on the risk-based process for mitigation of process-formed compounds. This workshop aimed to gain alignment from academia, government, and industry on a risk-based process for proactively assessing the need for and benefit of mitigation of process-formed compounds, including criteria to objectively assess the impact of mitigation as well as research needed to support this process. Workshop participants provided real-time feedback on a draft framework in the form of a decision tree developed by the ILSI North America Technical Committee on Food and Chemical Safety to a panel of experts, and they discussed the importance of communicating the value of such a process to the larger scientific community and, ultimately, the public. The outcome of the workshop was a decision tree that can be used by the scientific community and could form the basis of a global approach to assessing the risks associated with mitigation of process-formed compounds. © The Author(s) 2016.

A Risk-Based Strategy for Evaluating Mitigation Options for Process-Formed Compounds in Food

PubMed Central

Brorby, Gregory P.; Krishan, Mansi

2016-01-01

Processing (eg, cooking, grinding, drying) has changed the composition of food throughout the course of human history; however, awareness of process-formed compounds, and the potential need to mitigate exposure to those compounds, is a relatively recent phenomenon. In May 2015, the North American Branch of the International Life Sciences Institute (ILSI North America) Technical Committee on Food and Chemical Safety held a workshop on the risk-based process for mitigation of process-formed compounds. This workshop aimed to gain alignment from academia, government, and industry on a risk-based process for proactively assessing the need for and benefit of mitigation of process-formed compounds, including criteria to objectively assess the impact of mitigation as well as research needed to support this process. Workshop participants provided real-time feedback on a draft framework in the form of a decision tree developed by the ILSI North America Technical Committee on Food and Chemical Safety to a panel of experts, and they discussed the importance of communicating the value of such a process to the larger scientific community and, ultimately, the public. The outcome of the workshop was a decision tree that can be used by the scientific community and could form the basis of a global approach to assessing the risks associated with mitigation of process-formed compounds. PMID:27102178

[Definition and stabilization of processes I. Management processes and support in a Urology Department].

PubMed

Pascual, Carlos; Luján, Marcos; Mora, José Ramón; Chiva, Vicente; Gamarra, Manuela

2015-01-01

The implantation of total quality management models in clinical departments can better adapt to the 2009 ISO 9004 model. An essential part of implantation of these models is the establishment of processes and their stabilization. There are four types of processes: key, management, support and operative (clinical). Management processes have four parts: process stabilization form, process procedures form, medical activities cost estimation form and, process flow chart. In this paper we will detail the creation of an essential process in a surgical department, such as the process of management of the surgery waiting list.

Process strengths determine the forms of the relationship between plant species richness and primary productivity

PubMed Central

Wang, Zhenhong

2017-01-01

The current rates of biodiversity loss have exceeded the rates observed during the earth’s major extinction events, which spurs the studies of the ecological relationships between biodiversity and ecosystem functions, stability, and services to determine the consequences of biodiversity loss. Plant species richness-productivity relationship (SRPR) is crucial to the understanding of these relationships in plants. Most ecologists have reached a widespread consensus that the loss of plant diversity undoubtedly impairs ecosystem functions, and have proposed many processes to explain the SRPR. However, none of the available studies has satisfactorily described the forms and mechanisms clarifying the SRPR. Observed results of the SRPR forms are inconsistent, and studies have long debated the ecological processes explaining the SRPR. Here, I have developed a simple model that combines the positive and/or negative effects of sixteen ecological processes on the SRPR and models that describe the dynamics of complementary-selection effect, density effect, and the interspecific competitive stress influenced by other ecological processes. I can regulate the strengths of the effects of these ecological processes to derive the asymptotic, positive, humped, negative, and irregular forms of the SRPR, and verify these forms using the observed data. The results demonstrated that the different strengths of the ecological processes determine the forms of the SRPR. The forms of the SRPR can change with variations in the strengths of the ecological processes. The dynamic characteristics of the complementary-selection effect, density effect, and the interspecific competitive stress on the SRPR are diverse, and are dependent on the strengths and variation of the ecological processes. This report explains the diverse forms of the SRPR, clarifies the integrative effects of the different ecological processes on the SRPR, and deepens our understanding of the interactions that occur among these ecological processes. PMID:29140995

Numerical simulation on chain-die forming of an AHSS top-hat section

NASA Astrophysics Data System (ADS)

Majji, Raju; Xiang, Yang; Ding, Scott; Yang, Chunhui

2018-05-01

The applications of Advanced High-Strength Steels (AHSS) in the automotive industry are rapidly increasing due to a demand for a lightweight material that significantly reduces fuel consumption without compromising passenger safety. Automotive industries and material suppliers are expected by consumers to deliver reliable and affordable products, thus stimulating these manufacturers to research solutions to meet these customer requirements. The primary advantage of AHSS is its extremely high strength to weight ratio, an ideal material for the automotive industry. However, its low ductility is a major disadvantage, in particular, when using traditional cold forming processes such as roll forming and deep drawing process to form profiles. Consequently, AHSS parts frequently fail to form. Thereby, in order to improve quality and reliability on manufacturing AHSS products, a recently-developed incremental cold sheet metal forming technology called Chain-die Forming (CDF) is recognised as a potential solution to the forming process of AHSS. The typical CDF process is a combination of bending and roll forming processes which is equivalent to a roll with a large deforming radius, and incrementally forms the desired shape with split die and segments. This study focuses on manufacturing an AHSS top-hat section with minimum passes without geometrical or surface defects by using finite element modelling and simulations. The developed numerical simulation is employed to investigate the influences on the main control parameter of the CDF process while forming AHSS products and further develop new die-punch sets of compensation design via a numerical optimal process. In addition, the study focuses on the tool design to compensate spring-back and reduce friction between tooling and sheet-metal. This reduces the number of passes, thereby improving productivity and reducing energy consumption and material waste. This numerical study reveals that CDF forms AHSS products of complex profiles with much less residual stress, low spring back, low strain and of higher geometrical accuracy compared to other traditional manufacturing processes.

Experimental and numerical study on optimization of the single point incremental forming of AINSI 304L stainless steel sheet

NASA Astrophysics Data System (ADS)

Saidi, B.; Giraud-Moreau, L.; Cherouat, A.; Nasri, R.

2017-09-01

AINSI 304L stainless steel sheets are commonly formed into a variety of shapes for applications in the industrial, architectural, transportation and automobile fields, it’s also used for manufacturing of denture base. In the field of dentistry, there is a need for personalized devises that are custom made for the patient. The single point incremental forming process is highly promising in this area for manufacturing of denture base. The single point incremental forming process (ISF) is an emerging process based on the use of a spherical tool, which is moved along CNC controlled tool path. One of the major advantages of this process is the ability to program several punch trajectories on the same machine in order to obtain different shapes. Several applications of this process exist in the medical field for the manufacturing of personalized titanium prosthesis (cranial plate, knee prosthesis...) due to the need of product customization to each patient. The objective of this paper is to study the incremental forming of AISI 304L stainless steel sheets for future applications in the dentistry field. During the incremental forming process, considerable forces can occur. The control of the forming force is particularly important to ensure the safe use of the CNC milling machine and preserve the tooling and machinery. In this paper, the effect of four different process parameters on the maximum force is studied. The proposed approach consists in using an experimental design based on experimental results. An analysis of variance was conducted with ANOVA to find the input parameters allowing to minimize the maximum forming force. A numerical simulation of the incremental forming process is performed with the optimal input process parameters. Numerical results are compared with the experimental ones.

Digitalization in roll forming manufacturing

NASA Astrophysics Data System (ADS)

Sedlmaier, A.; Dietl, T.; Ferreira, P.

2017-09-01

Roll formed profiles are used in automotive chassis production as building blocks for the body-in-white. The ability to produce profiles with discontinuous cross sections, both in width and in depth, allows weight savings in the final automotive chassis through the use of load optimized cross sections. This has been the target of the 3D Roll Forming process. A machine concept is presented where a new forming concept for roll formed parts in combination with advanced robotics allowing freely positioned roll forming tooling in 3D space enables the production of complex shapes by roll forming. This is a step forward into the digitalization of roll forming manufacturing by making the process flexible and capable of rapid prototyping and production of small series of parts. Moreover, data collection in a large scale through the control system and integrated sensors lead to an increased understanding of the process and provide the basis to develop self-optimizing roll forming machines, increasing the productivity, quality and predictability of the roll-forming process. The first parts successfully manufactured with this new forming concept are presented.

Numerical simulation of X90 UOE pipe forming process

NASA Astrophysics Data System (ADS)

Zou, Tianxia; Ren, Qiang; Peng, Yinghong; Li, Dayong; Tang, Ding; Han, Jianzeng; Li, Xinwen; Wang, Xiaoxiu

2013-12-01

The UOE process is an important technique to manufacture large-diameter welding pipes which are increasingly applied in oil pipelines and offshore platforms. The forming process of UOE mainly consists of five successive operations: crimping, U-forming, O-forming, welding and mechanical expansion, through which a blank is formed into a pipe in a UOE pipe mill. The blank with an appropriate edge bevel is bent into a cylindrical shape by crimping (C-forming), U-forming and O-forming successively. After the O-forming, there is an open-seam between two ends of the plate. Then, the blank is welded by automatic four-electrode submerged arc welding technique. Subsequently, the welded pipe is expanded with a mechanical expander to get a high precision circular shape. The multiple operations in the UOE mill make it difficult to control the quality of the formed pipe. Therefore, process design mainly relies on experience in practical production. In this study, the UOE forming of an API X90 pipe is studied by using finite element simulation. The mechanical properties tests are performed on the API X90 pipeline steel blank. A two-dimensional finite element model under the hypothesis of plane strain condition is developed to simulate the UOE process according to data coming from the workshop. A kinematic hardening model is used in the simulation to take the Bauschinger effect into account. The deformation characteristics of the blank during the forming processes are analyzed. The simulation results show a significant coherence in the geometric configurations comparing with the practical manufacturing.

Keep Your Eyes on Development: The Behavioral and Neurophysiological Development of Visual Mechanisms Underlying Form Processing

PubMed Central

van den Boomen, C.; van der Smagt, M. J.; Kemner, C.

2012-01-01

Visual form perception is essential for correct interpretation of, and interaction with, our environment. Form perception depends on visual acuity and processing of specific form characteristics, such as luminance contrast, spatial frequency, color, orientation, depth, and even motion information. As other cognitive processes, form perception matures with age. This paper aims at providing a concise overview of our current understanding of the typical development, from birth to adulthood, of form-characteristic processing, as measured both behaviorally and neurophysiologically. Two main conclusions can be drawn. First, the current literature conveys that for most reviewed characteristics a developmental pattern is apparent. These trajectories are discussed in relation to the organization of the visual system. The second conclusion is that significant gaps in the literature exist for several age-ranges. To complete our understanding of the typical and, by consequence, atypical development of visual mechanisms underlying form processing, future research should uncover these missing segments. PMID:22416236

Alpha and gamma band oscillations index differential processing of acoustically reduced and full forms.

PubMed

Drijvers, Linda; Mulder, Kimberley; Ernestus, Mirjam

2016-02-01

Reduced forms like yeshay for yesterday often occur in conversations. Previous behavioral research reported a processing advantage for full over reduced forms. The present study investigated whether this processing advantage is reflected in a modulation of alpha (8-12Hz) and gamma (30+Hz) band activity. In three electrophysiological experiments, participants listened to full and reduced forms in isolation (Experiment 1), sentence-final position (Experiment 2), or mid-sentence position (Experiment 3). Alpha power was larger in response to reduced forms than to full forms, but only in Experiments 1 and 2. We interpret these increases in alpha power as reflections of higher auditory cognitive load. In all experiments, gamma power only increased in response to full forms, which we interpret as showing that lexical activation spreads more quickly through the semantic network for full than for reduced forms. These results confirm a processing advantage for full forms, especially in non-medial sentence position. Copyright © 2016 Elsevier Inc. All rights reserved.

Normal form from biological motion despite impaired ventral stream function.

PubMed

Gilaie-Dotan, S; Bentin, S; Harel, M; Rees, G; Saygin, A P

2011-04-01

We explored the extent to which biological motion perception depends on ventral stream integration by studying LG, an unusual case of developmental visual agnosia. LG has significant ventral stream processing deficits but no discernable structural cortical abnormality. LG's intermediate visual areas and object-sensitive regions exhibit abnormal activation during visual object perception, in contrast to area V5/MT+ which responds normally to visual motion (Gilaie-Dotan, Perry, Bonneh, Malach, & Bentin, 2009). Here, in three studies we used point light displays, which require visual integration, in adaptive threshold experiments to examine LG's ability to detect form from biological and non-biological motion cues. LG's ability to detect and discriminate form from biological motion was similar to healthy controls. In contrast, he was significantly deficient in processing form from non-biological motion. Thus, LG can rely on biological motion cues to perceive human forms, but is considerably impaired in extracting form from non-biological motion. Finally, we found that while LG viewed biological motion, activity in a network of brain regions associated with processing biological motion was functionally correlated with his V5/MT+ activity, indicating that normal inputs from V5/MT+ might suffice to activate his action perception system. These results indicate that processing of biologically moving form can dissociate from other form processing in the ventral pathway. Furthermore, the present results indicate that integrative ventral stream processing is necessary for uncompromised processing of non-biological form from motion. Copyright © 2011 Elsevier Ltd. All rights reserved.

CTEPP STANDARD OPERATING PROCEDURE FOR PROCESSING COMPLETED DATA FORMS (SOP-4.10)

EPA Science Inventory

This SOP describes the methods for processing completed data forms. Key components of the SOP include (1) field editing, (2) data form Chain-of-Custody, (3) data processing verification, (4) coding, (5) data entry, (6) programming checks, (7) preparation of data dictionaries, cod...

Numerical analysis of the flexible roll forming of an automotive component from high strength steel

NASA Astrophysics Data System (ADS)

Abeyrathna, B.; Abvabi, A.; Rolfe, B.; Taube, R.; Weiss, M.

2016-11-01

Conventional roll forming is limited to components with uniform cross-section; the recently developed flexible roll forming (FRF) process can be used to form components which vary in both width and depth. It has been suggested that this process can be used to manufacture automotive components from Ultra High Strength Steel (UHSS) which has limited tensile elongation. In the flexible roll forming process, the pre-cut blank is fed through a set of rolls; some rolls are computer-numerically controlled (CNC) to follow the 3D contours of the part and hence parts with a variable cross-section can be produced. This paper introduces a new flexible roll forming technique which can be used to form a complex shape with the minimum tooling requirements. In this method, the pre-cut blank is held between two dies and the whole system moves back and forth past CNC forming rolls. The forming roll changes its angle and position in each pass to incrementally form the part. In this work, the process is simulated using the commercial software package Copra FEA. The distribution of total strain and final part quality are investigated as well as related shape defects observed in the process. Different tooling concepts are used to improve the strain distribution and hence the part quality.

Ductile Damage and Fatigue Behavior of Semi-Finished Tailored Blanks for Sheet-Bulk Metal Forming Processes

NASA Astrophysics Data System (ADS)

Besserer, Hans-Bernward; Hildenbrand, Philipp; Gerstein, Gregory; Rodman, Dmytro; Nürnberger, Florian; Merklein, Marion; Maier, Hans Jürgen

2016-03-01

To produce parts from sheet metal with thickened functional elements, bulk forming operations can be employed. For this new process class, the term sheet-bulk metal forming has been established recently. Since sheet-bulk metal forming processes such as orbital forming generates triaxial stress and strain states, ductile damage is induced in the form of voids in the microstructure. Typical parts will experience cyclic loads during service, and thus, the influence of ductile damage on the fatigue life of parts manufactured by orbital forming is of interest. Both the formation and growth of voids were characterized following this forming process and then compared to the as-received condition of the ferritic deep drawing steel DC04 chosen for this study. Subsequent to the forming operation, the specimens were fatigued and the evolution of ductile damage and the rearrangement of the dislocation networks occurring during cyclic loading were determined. It was shown, that despite an increased ductile damage due to the forming process, the induced strain hardening has a positive effect on the fatigue life of the material. However, by analyzing the fatigued specimens a development of the ductile damage by an increasing number of voids and a change in the void shape were detected.

77 FR 21618 - 60-Day Notice of Proposed Information Collection: Civilian Response Corps Database In-Processing...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-10

... DEPARTMENT OF STATE [Public Notice 7843] 60-Day Notice of Proposed Information Collection: Civilian Response Corps Database In-Processing Electronic Form, OMB Control Number 1405-0168, Form DS-4096... Collection: Civilian Response Corps Database In-Processing Electronic Form. OMB Control Number: 1405-0168...

77 FR 47690 - 30-Day Notice of Proposed Information Collection: Civilian Response Corps Database In-Processing...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-09

... DEPARTMENT OF STATE [Public Notice 7976] 30-Day Notice of Proposed Information Collection: Civilian Response Corps Database In-Processing Electronic Form, OMB Control Number 1405-0168, Form DS-4096.... Title of Information Collection: Civilian Response Corps Database In-Processing Electronic Form. OMB...

Process for the preparation of protected dihydroxypropyl trialkylammonium salts and derivatives thereof

DOEpatents

Hollingsworth, Rawle I.; Wang, Guijun

2000-01-01

A process for the preparation of protected dihydroxypropyl trialkylammonium salts, particularly in chiral form is described. In particular, a process for the preparation of (2,2-dimethyl-1,3-dioxolan-4-ylmethyl)trialkylammonium salts, particularly in chiral form is described. Furthermore, a process is described wherein the (2,2-dimethyl-1,3-dioxolan-4ylmethyl)trialkylammonium salts is a 2,2-dimethyl-1,3-dioxolan-4-ylmethyl trimethylammonium salt, preferably in chiral form. The protected dihydroxypropyl trialkylammonium salts lead to L-carnitine (9) when in chiral form (5).

Fabricating a hybrid imaging device

NASA Technical Reports Server (NTRS)

Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

2003-01-01

A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

Modeling and FE Simulation of Quenchable High Strength Steels Sheet Metal Hot Forming Process

NASA Astrophysics Data System (ADS)

Liu, Hongsheng; Bao, Jun; Xing, Zhongwen; Zhang, Dejin; Song, Baoyu; Lei, Chengxi

2011-08-01

High strength steel (HSS) sheet metal hot forming process is investigated by means of numerical simulations. With regard to a reliable numerical process design, the knowledge of the thermal and thermo-mechanical properties is essential. In this article, tensile tests are performed to examine the flow stress of the material HSS 22MnB5 at different strains, strain rates, and temperatures. Constitutive model based on phenomenological approach is developed to describe the thermo-mechanical properties of the material 22MnB5 by fitting the experimental data. A 2D coupled thermo-mechanical finite element (FE) model is developed to simulate the HSS sheet metal hot forming process for U-channel part. The ABAQUS/explicit model is used conduct the hot forming stage simulations, and ABAQUS/implicit model is used for accurately predicting the springback which happens at the end of hot forming stage. Material modeling and FE numerical simulations are carried out to investigate the effect of the processing parameters on the hot forming process. The processing parameters have significant influence on the microstructure of U-channel part. The springback after hot forming stage is the main factor impairing the shape precision of hot-formed part. The mechanism of springback is advanced and verified through numerical simulations and tensile loading-unloading tests. Creep strain is found in the tensile loading-unloading test under isothermal condition and has a distinct effect on springback. According to the numerical and experimental results, it can be concluded that springback is mainly caused by different cooling rats and the nonhomogengeous shrink of material during hot forming process, the creep strain is the main factor influencing the amount of the springback.

Simulation of friction stir drilling process

NASA Astrophysics Data System (ADS)

Vijayabaskar, P.; Hynes, N. Rajesh Jesudoss

2018-05-01

The project is the study of the thermal drilling process. The process is a hole forming process in the sheet metals using the heat generated by means of friction. The main advantage of the process over the conventional drilling process is that the holes formed using this process does not need any backing arrangements such as weld nuts, rivet nuts etc. Because the extruded bush itself acts as a supporting structure for the fasteners. This eliminates the need for the access to the backside of the work material for fastening operations. The major factors contributing the thermal drilling operation are the spindle speed and the thrust force required for forming a hole. The process of finding out the suitable thrust force and the speed for drilling a particular material with particular thickness is a tedious process. The process can be simplified by forming a mathematical model by combining the empirical formulae from the literature. These formulae were derived in the literature from the experimental trials by following certain assumptions. In this paper a suitable mathematical model is formed by replicating the experiments and tried to be validated by the results from numerical analysis. The numerical analysis of the model is done using the ANSYS software.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Junfeng, E-mail: chenjunfeng@fzu.edu.cn; Zou, Linchi, E-mail: zoulinchi1201@163.com; Li, Qiang

The microstructure evolution of the 7050 Al alloy treated by age-forming was studied using a designed device which can simulate the age-forming process. The grain shape, grain boundary misorientation and grain orientation evolution of 7050 Al alloy during age-forming have been quantitatively characterized by electron backscattering diffraction technique. The results show that age-forming produced abundant low-angle boundaries and elongated grains, which attributed to stress induced dislocation movement and grain boundary migration during the age-forming process. On the other side, the stress along rolling direction caused some unstable orientation grains to rotate towards the Brass and S orientations during the age-formingmore » process. Hence, the intensity of the rolling texture orientation in age-formed samples is enhanced. But this effect decays gradually with increasing aging time, since stress decreases and precipitation hardening occurs during the age-forming process. - Highlights: • Quantitative analysis of grain evolution of 7050 Al alloys during age-forming • Stress induces some grain rotation of 7050 Al alloys during age-forming. • Creep leads to elongate grain of 7050 Al alloys during age-forming. • Obtains a trend on texture evolution during age-forming applied stress.« less

Electrohydraulic Forming of Near-Net Shape Automotive Panels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golovaschenko, Sergey F.

2013-09-26

The objective of this project was to develop the electrohydraulic forming (EHF) process as a near-net shape automotive panel manufacturing technology that simultaneously reduces the energy embedded in vehicles and the energy consumed while producing automotive structures. Pulsed pressure is created via a shockwave generated by the discharge of high voltage capacitors through a pair of electrodes in a liquid-filled chamber. The shockwave in the liquid initiated by the expansion of the plasma channel formed between two electrodes propagates towards the blank and causes the blank to be deformed into a one-sided die cavity. The numerical model of the EHFmore » process was validated experimentally and was successfully applied to the design of the electrode system and to a multi-electrode EHF chamber for full scale validation of the process. The numerical model was able to predict stresses in the dies during pulsed forming and was validated by the experimental study of the die insert failure mode for corner filling operations. The electrohydraulic forming process and its major subsystems, including durable electrodes, an EHF chamber, a water/air management system, a pulse generator and integrated process controls, were validated to be capable to operate in a fully automated, computer controlled mode for forming of a portion of a full-scale sheet metal component in laboratory conditions. Additionally, the novel processes of electrohydraulic trimming and electrohydraulic calibration were demonstrated at a reduced-scale component level. Furthermore, a hybrid process combining conventional stamping with EHF was demonstrated as a laboratory process for a full-scale automotive panel formed out of AHSS material. The economic feasibility of the developed EHF processes was defined by developing a cost model of the EHF process in comparison to the conventional stamping process.« less

Process for the enhanced capture of heavy metal emissions

DOEpatents

Biswas, Pratim; Wu, Chang-Yu

2001-01-01

This invention is directed to a process for forming a sorbent-metal complex. The process includes oxidizing a sorbent precursor and contacting the sorbent precursor with a metallic species. The process further includes chemically reacting the sorbent precursor and the metallic species, thereby forming a sorbent-metal complex. In one particular aspect of the invention, at least a portion of the sorbent precursor is transformed into sorbent particles during the oxidation step. These sorbent particles then are contacted with the metallic species and chemically reacted with the metallic species, thereby forming a sorbent-metal complex. Another aspect of the invention is directed to a process for forming a sorbent metal complex in a combustion system. The process includes introducing a sorbent precursor into a combustion system and subjecting the sorbent precursor to an elevated temperature sufficient to oxidize the sorbent precursor and transform the sorbent precursor into sorbent particles. The process further includes contacting the sorbent particles with a metallic species and exposing the sorbent particles and the metallic species to a complex-forming temperature whereby the metallic species reacts with the sorbent particles thereby forming a sorbent-metal complex under UV irradiation.

Microstructural analysis of hot press formed 22MnB5 steel

NASA Astrophysics Data System (ADS)

Aziz, Nuraini; Aqida, Syarifah Nur; Ismail, Izwan

2017-10-01

This paper presents a microstructural study on hot press formed 22MnB5 steel for enhanced mechanical properties. Hot press forming process consists of simultaneous forming and quenching of heated blank. The 22MnB5 steel was processed at three different parameter settings: quenching time, water temperature and water flow rate. 22MnB5 was processed using 33 full factorial design of experiment (DOE). The full factorial DOE was designed using three factors of quenching time, water temperature and water flow rate at three levels. The factors level were quenching time range of 5 - 11 s, water temperature; 5 - 27°C and water flow rate; 20 - 40 L/min. The as-received and hot press forming processed steel was characterised for metallographic study and martensitic structure area percentage using JEOL Field Emission Scanning Electron Microscopic (FESEM). From the experimental finding, the hot press formed 22MnB5 steel consisted of 50 to 84% martensitic structure area. The minimum quenching time of 8 seconds was required to obtain formed sample with high percentage of martensite. These findings contribute to initial design of processing parameters in hot press forming of 22MnB5 steel blanks for automotive component.

Low-Flammability PTFE for High-Oxygen Environments

NASA Technical Reports Server (NTRS)

Walle, E.; Fallon, B.; Sheppard, A.

1986-01-01

Modified forming process removes volatile combustible materials. Flammability of cable-wrapping tape reduced by altering tape-manufacturing process. In new manufacturing process, tape formed by proprietary process of screw extrusion, followed by washing in solvent and drying. Tape then wrapped as before. Spectrogram taken after extrusion, washing, and drying shows lower hydrocarbon content. PTFE formed by new process suited to oxygen-rich environments. Safe in liquid oxygen of Space Shuttle tank and in medical uses; thin-wall shrinkable tubing in hospital test equipment, surgical instruments, and implants.

Composite hot drape forming

NASA Technical Reports Server (NTRS)

Ott, Thomas

1994-01-01

This program was initiated to replace labor-intensive ply-by-ply layup of composite I-beam posts and angle stiffeners used in the Space Station Freedom (SSF) rack structure. Hot drape forming (HDF) has been successfully implemented by BCAG for 777 composite I-stringers and by Bell Helicopter/Textron for the V-22 I-stingers. The two companies utilize two vastly different approaches to the I-beam fabrication process. A drape down process is used by Bell Helicopter where the compacted ply charge is placed on top of a forming mandrel and heated. When the heated ply charge reached a set temperature, vacuum pressure is applied and the plies are formed over the mandrel. The BCAG 777 process utilizes an inverted forming process where the ply stack is placed on a forming table and the mandrel is inverted and placed upon the ply stack. A heating and vacuum bladder underneath the ply stack form the play stack up onto the mandrels after reaching the temperature setpoint. Both methods have their advantages, but the drape down process was selected for SSF because it was more versatile and could be fabricated from readily available components.

Fabricating a hybrid imaging device having non-destructive sense nodes

NASA Technical Reports Server (NTRS)

Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

2001-01-01

A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

Volatile organic compound constituents from an integrated iron and steel facility.

PubMed

Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Lai, Nina; Ma, Sen-Yi; Chiang, Hung-Lung

2008-09-15

This study measured the volatile organic compound (VOC) constituents of four processes in an integrated iron and steel industry; cokemaking, sintering, hot forming, and cold forming. Toluene, 1,2,4-trimethylbenzene, isopentane, m,p-xylene, 1-butene, ethylbenzene, and benzene were the predominant VOC species in these processes. However, some of the chlorinated compounds were high (hundreds ppbv), i.e., trichloroethylene in all four processes, carbon tetrachloride in the hot forming process, chlorobenzene in the cold forming process, and bromomethane in the sintering process. In the sintering process, the emission factors of toluene, benzene, xylene, isopentane, 1,2,4-trimethylbenzene, and ethylbenzene were over 9 g/tonne-product. In the vicinity of the manufacturing plant, toluene, isopentane, 1,2,4-trimethylbenzene, xylene and ethylbenzene were high. Toluene, 1,2,4-trimethylbenzene, xylene, 1-butene and isopentane were the major ozone formation species. Aromatic compounds were the predominant VOC groups, constituting 45-70% of the VOC concentration and contributing >70% to the high ozone formation potential in the stack exhaust and workplace air. The sequence of VOC concentration and ozone formation potential was as follows: cold forming>sintering>hot forming>cokemaking. For the workplace air, cokemaking was the highest producer, which was attributed to the fugitive emissions of the coke oven and working process release.

West Valley demonstration project: Alternative processes for solidifying the high-level wastes

NASA Astrophysics Data System (ADS)

Holton, L. K.; Larson, D. E.; Partain, W. L.; Treat, R. L.

1981-10-01

Two pretreatment approaches and several waste form processes for radioactive wastes were selected for evaluation. The two waste treatment approaches were the salt/sludge separation process and the combined waste process. Both terminal and interim waste form processes were studied.

Monitoring of multiple solvent induced form changes during high shear wet granulation and drying processes using online Raman spectroscopy.

PubMed

Reddy, Jay Poorna; Jones, John W; Wray, Patrick S; Dennis, Andrew B; Brown, Jonathan; Timmins, Peter

2018-04-25

Form changes during drug product processing can be a risk to the final product quality in terms of chemical stability and bioavailability. In this study, online Raman spectroscopy was used to monitor the form changes in real time during high shear wet granulation of Compound A, a highly soluble drug present at a high drug load in an extended release formulation. The effect of water content, temperature, wet massing time and drying technique on the degree of drug transformation were examined. A designed set of calibration standards were employed to develop quantitative partial least square regression models to predict the concentration of each drug form during both wet granulation and the drying process. Throughout all our experiments we observed complex changes of the drug form during granulation, manifest as conversions between the initial non-solvated form of Compound A, the hemi-hydrate form and the "apparent" amorphous form (dissolved drug). The online Raman data demonstrate that the non-solvated form converts to an "apparent" amorphous form (dissolved drug) due to drug dissolution with no appearance of the hemi-hydrate form during water addition stage. The extent of conversion of the non-solvated form was governed by the amount of water added and the rate of conversion was accelerated at higher temperatures. Interestingly, in the wet massing zone, the formation of the hemi-hydrate form was observed at a rate equivalent to the rate of depletion of the non-solvated form with no change in the level of the "apparent amorphous" form generated. The level of hemi-hydrate increased with an increase in wet massing time. The drying process had a significant effect on the proportion of each form. During tray drying, changes in drug form continued for hours. In contrast fluid bed drying appeared to lock the final proportions of drug form product attained during granulation, with comparatively small changes observed during drying. In conclusion, it was possible to simultaneously monitor the three forms in real time during wet granulation and drying using online Raman spectroscopy. The results regarding the effect of process parameters on the degree of transformation are critical for designing a robust process that ensures a consistent form in the final drug product. Copyright © 2018 Elsevier B.V. All rights reserved.

Improving the readability and processability of a pediatric informed consent document: effects on parents' understanding.

PubMed

Tait, Alan R; Voepel-Lewis, Terri; Malviya, Shobha; Philipson, Sandra J

2005-04-01

To examine whether a consent document modified to conform with the federal guidelines for readability and processability would result in greater parental understanding compared with a standard form. Randomized clinical study. The preoperative waiting area of a larger tertiary care children's hospital. A total of 305 parents of children scheduled for minor elective surgical procedures. Parents were randomized to receive information about a clinical study in 1 of 4 ways: (1) standard consent form alone, (2) standard consent form with verbal disclosure, (3) modified form alone (standard form modified to meet the federal guidelines for readability and processability), and (4) modified form with verbal disclosure. Parents were interviewed to determine their understanding of 11 elements of consent, including study purpose, protocol, risks, benefits to child (direct), benefit to others (indirect), freedom to withdraw, alternatives, duration of study, voluntariness, confidentiality, and whom to contact. Their responses were scored by 2 independent assessors. Understanding of the protocol, study duration, risks, and direct benefits, together with overall understanding, was greater among parents who received the modified form (P<.001). Additionally, parents reported that the modified form had greater clarity (P = .009) and improved layout compared with the standard form (P<.001). When parents were shown both forms, 81.2% preferred the modified version. Results suggest that a consent form written according to federal guidelines for readability and processability can improve parent understanding and thus will be important in enhancing the informed consent process.

Method of forming composite fiber blends

NASA Technical Reports Server (NTRS)

McMahon, Paul E. (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

1989-01-01

The instant invention involves a process used in preparing fibrous tows which may be formed into polymeric plastic composites. The process involves the steps of (a) forming a tow of strong filamentary materials; (b) forming a thermoplastic polymeric fiber; (c) intermixing the two tows; and (d) withdrawing the intermixed tow for further use.

Conditioning of material properties by micro rotary swaging

NASA Astrophysics Data System (ADS)

Ishkina, Svetlana; Schenck, Christian; Kuhfuss, Bernd

2018-05-01

Cold forming initiates a change of the material properties like flow stress and hardness. Due to work hardening and the accompanied loss of formability some intermediate heat treatment may become necessary in multi-stage forming processes. One possibility to avoid this heat treatment is to adjust the forming characteristics in terms of flow stress and formability by rotary swaging. This process is particularly suitable not only for producing of the target geometry but also for modifying of the material properties during the process and thus, rotary swaging can prepare the parts for further forming, such as extrusion. In this contribution, the process chain "rotary swaging - extrusion" for austenite stainless steel AISI304 was investigated. The forming characteristics of the semi-finished products for the extrusion were influenced by the previous swaging process. The conditioning by changing of the microstructure, the work hardening and the geometry of the processed wires was achieved by the process design. For this purpose, the geometry of the swaging dies, the feeding velocity as well as the process kinematics (eccentric swaging) and a stroke following angle Δɸ were varied. In particular, the novel geometry of the swaging dies with extraordinary sloped faces generated a non-symmetric material flow with severe shear deformation and thus an extreme change of the microstructure. The required forming force of the following extrusion process reflected the range of achievable conditioning. The micro rotary swaging process positively improved the formability of AISI304 by work softening.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR BATCHING OF FIELD DATA FORMS (UA-C-4.0)

EPA Science Inventory

The purpose of this SOP is to describe the assembly of household (HH) packets into data processing batches. The batching process enables orderly tracking of packets or forms through data processing and limits the potential for packet or form loss. This procedure was used for th...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR BATCHING OF FIELD DATA FORMS (UA-C-4.0)

EPA Science Inventory

The purpose of this SOP is to describe the assembly of household (HH) packets into data processing batches. The batching process enables orderly tracking of packets or forms through data processing and limits the potential for packet or form loss. This procedure was used for th...

Process for forming coal compacts and product thereof

DOEpatents

Gunnink, Brett; Kanunar, Jayanth; Liang, Zhuoxiong

2002-01-01

A process for forming durable, mechanically strong compacts from coal particulates without use of a binder is disclosed. The process involves applying a compressive stress to a particulate feed comprising substantially water-saturated coal particles while the feed is heated to a final compaction temperature in excess of about 100.degree. C. The water present in the feed remains substantially in the liquid phase throughout the compact forming process. This is achieved by heating and compressing the particulate feed and cooling the formed compact at a pressure sufficient to prevent water present in the feed from boiling. The compacts produced by the process have a moisture content near their water saturation point. As a result, these compacts absorb little water and retain exceptional mechanical strength when immersed in high pressure water. The process can be used to form large, cylindrically-shaped compacts from coal particles (i.e., "coal logs") so that the coal can be transported in a hydraulic coal log pipeline.

Control and monitoring method and system for electromagnetic forming process

DOEpatents

Kunerth, Dennis C.; Lassahn, Gordon D.

1990-01-01

A process, system, and improvement for a process for electromagnetic forming of a workpiece in which characteristics of the workpiece such as its geometry, electrical conductivity, quality, and magnetic permeability can be determined by monitoring the current and voltage in the workcoil. In an electromagnet forming process in which a power supply provides current to a workcoil and the electromagnetic field produced by the workcoil acts to form the workpiece, the dynamic interaction of the electromagnetic fields produced by the workcoil with the geometry, electrical conductivity, and magnetic permeability of the workpiece, provides information pertinent to the physical condition of the workpiece that is available for determination of quality and process control. This information can be obtained by deriving in real time the first several time derivatives of the current and voltage in the workcoil. In addition, the process can be extended by injecting test signals into the workcoil during the electromagnetic forming and monitoring the response to the test signals in the workcoil.

Advances in solid dosage form manufacturing technology.

PubMed

Andrews, Gavin P

2007-12-15

Currently, the pharmaceutical and healthcare industries are moving through a period of unparalleled change. Major multinational pharmaceutical companies are restructuring, consolidating, merging and more importantly critically assessing their competitiveness to ensure constant growth in an ever-more demanding market where the cost of developing novel products is continuously increasing. The pharmaceutical manufacturing processes currently in existence for the production of solid oral dosage forms are associated with significant disadvantages and in many instances provide many processing problems. Therefore, it is well accepted that there is an increasing need for alternative processes to dramatically improve powder processing, and more importantly to ensure that acceptable, reproducible solid dosage forms can be manufactured. Consequently, pharmaceutical companies are beginning to invest in innovative processes capable of producing solid dosage forms that better meet the needs of the patient while providing efficient manufacturing operations. This article discusses two emerging solid dosage form manufacturing technologies, namely hot-melt extrusion and fluidized hot-melt granulation.

Effect of Bottoming on Material Property during Sheet Forming Process through Finite Element Method

NASA Astrophysics Data System (ADS)

Akinlabi, Stephen A.; Fatoba, Olawale S.; Mashinini, Peter M.; Akinlabi, Esther T.

2018-03-01

Metal forming is one of the conventional manufacturing processes of immense relevance till date even though modern manufacturing processes have evolved over the years. It is a known fact that material tends to return or spring back to its original form during forming or bending. The phenomena have been well managed through its application in various manufacturing processes by compensating for the spring back through overbending and bottoming. Overbending is bending the material beyond the desired shape to allow the material to spring back to the expected shape. Bottoming, on the other hand, is a process of undergoing plastic deformation at the point of bending. This study reports on the finite element analysis of the effect of bottoming on the material property during the sheet forming process with the aim of optimising the process. The result of the analysis revealed that the generated plastic strains are in the order between 1.750e00-1 at the peak of the bending and 3.604e00-2, which was at the early stage of the bending.

Characterization of Al 2219 material for the application of the spin-forming-process

NASA Astrophysics Data System (ADS)

Mueller-Wiesner, D.; Sieger, E.; Ernsberger, K.

1991-10-01

The shells of the propellant tanks of the Ariane 5 EPS stage are to be manufactured by the spin forming process. The material for the shells (hemispheres) is the aluminum alloy 2219. By a material characterization program optimized parameters for the application of the forming process starting from different material conditions (T31 temper and '0' condition) are determined. Based on the results of this program it was decided to start spin forming in the '0' condition for flight hardware.

Process for Forming a High Temperature Single Crystal Canted Spring

NASA Technical Reports Server (NTRS)

DeMange, Jeffrey J (Inventor); Ritzert, Frank J (Inventor); Nathal, Michael V (Inventor); Dunlap, Patrick H (Inventor); Steinetz, Bruce M (Inventor)

2017-01-01

A process for forming a high temperature single crystal canted spring is provided. In one embodiment, the process includes fabricating configurations of a rapid prototype spring to fabricate a sacrificial mold pattern to create a ceramic mold and casting a canted coiled spring to form at least one canted coil spring configuration based on the ceramic mold. The high temperature single crystal canted spring is formed from a nickel-based alloy containing rhenium using the at least one coil spring configuration.

Method of forming composite fiber blends and molding same

NASA Technical Reports Server (NTRS)

McMahon, Paul E. (Inventor); Chung, Tai-Shung (Inventor)

1989-01-01

The instant invention involves a process used in preparing fibrous tows which may be formed into polymeric plastic composites. The process involves the steps of (a) forming a tow of strong filamentary materials; (b) forming a thermoplastic polymeric fiber; (c) intermixing the two tows; and (d) withdrawing the intermixed tow for further use.

A slow atomic diffusion process in high-entropy glass-forming metallic melts

NASA Astrophysics Data System (ADS)

Chen, Changjiu; Wong, Kaikin; Krishnan, Rithin P.; Embs, Jan P.; Chathoth, Suresh M.

2018-04-01

Quasi-elastic neutron scattering has been used to study atomic relaxation processes in high-entropy glass-forming metallic melts with different glass-forming ability (GFA). The momentum transfer dependence of mean relaxation time shows a highly collective atomic transport process in the alloy melts with the highest and lowest GFA. However, a jump diffusion process is the long-range atomic transport process in the intermediate GFA alloy melt. Nevertheless, atomic mobility close to the melting temperature of these alloy melts is quite similar, and the temperature dependence of the diffusion coefficient exhibits a non-Arrhenius behavior. The atomic mobility in these high-entropy melts is much slower than that of the best glass-forming melts at their respective melting temperatures.

Effect of thermal and mechanical parameter’s damage numerical simulation cycling effects on defects in hot metal forming processes

NASA Astrophysics Data System (ADS)

El Amri, Abdelouahid; el yakhloufi Haddou, Mounir; Khamlichi, Abdellatif

2017-10-01

Damage mechanisms in hot metal forming processes are accelerated by mechanical stresses arising during Thermal and mechanical properties variations, because it consists of the materials with different thermal and mechanical loadings and swelling coefficients. In this work, 3D finite element models (FEM) are developed to simulate the effect of Temperature and the stresses on the model development, using a general purpose FE software ABAQUS. Explicit dynamic analysis with coupled Temperature displacement procedure is used for a model. The purpose of this research was to study the thermomechanical damage mechanics in hot forming processes. The important process variables and the main characteristics of various hot forming processes will also be discussed.

Using artificial neural networks to model aluminium based sheet forming processes and tools details

NASA Astrophysics Data System (ADS)

Mekras, N.

2017-09-01

In this paper, a methodology and a software system will be presented concerning the use of Artificial Neural Networks (ANNs) for modeling aluminium based sheet forming processes. ANNs models’ creation is based on the training of the ANNs using experimental, trial and historical data records of processes’ inputs and outputs. ANNs models are useful in cases that processes’ mathematical models are not accurate enough, are not well defined or are missing e.g. in cases of complex product shapes, new material alloys, new process requirements, micro-scale products, etc. Usually, after the design and modeling of the forming tools (die, punch, etc.) and before mass production, a set of trials takes place at the shop floor for finalizing processes and tools details concerning e.g. tools’ minimum radii, die/punch clearance, press speed, process temperature, etc. and in relation with the material type, the sheet thickness and the quality achieved from the trials. Using data from the shop floor trials and forming theory data, ANNs models can be trained and created, and can be used to estimate processes and tools final details, hence supporting efficient set-up of processes and tools before mass production starts. The proposed ANNs methodology and the respective software system are implemented within the EU H2020 project LoCoMaTech for the aluminium-based sheet forming process HFQ (solution Heat treatment, cold die Forming and Quenching).

Experimental Study on Ice Forming Process of Cryogenic Liquid Releasing underwater

NASA Astrophysics Data System (ADS)

Zhang, Bin; Wu, Wanqing; Zhang, Xingdong; Zhang, Yi; Zhang, Chuanlin; Zhang, Haoran; Wang, Peng

2017-11-01

Cryogenic liquid releasing into water would be a process combines hyperactive boiling with ice forming. There are still few researches on the experimental study on the environmental conditions for deciding ice forming speed and liquid surviving state. In this paper, to advance our understanding of ice forming deciding factors in the process of LN2 releasing underwater, a visualization experimental system is built. The results show that the pressure difference significantly influences the ice forming speed and liquid surviving distance, which is observed by the experiment and theoretically analysed by Kelvin-Helmholtz instability. Adding nucleating agent is helpful to provide ice nucleus which can accelerate the ice forming speed. Water flowing has some effect on changing pressure difference, which can affect the ice forming speed and liquid surviving distance.

Finite element modelling of chain-die forming for ultra-high strength steel

NASA Astrophysics Data System (ADS)

Majji, Raju; Xiang, Yang; Ding, Scott; Yang, Chunhui

2017-10-01

There has been a high demand for weight reduction in automotive vehicles while maintaining passenger safety. A potential steel material to achieve this is Ultra High Strength Steel (UHSS). As a high strength material, it is difficult to be formed with desired profiles using traditional sheet metal forming processes such as Cold Roll Forming. To overcome this problem, a potentially alternative solution is Chain-die Forming (CDF), recently developed. The basic principal of the CDF is to fully combine roll forming and bending processes. The main advantage of this process is the elongated deformation length that significantly increases effective roll radius. This study focuses on identifying issues with the CDF by using CAD modelling, Motion Analysis and Finite Element Analysis (FEA) to devise solutions and construct a more reliable process in an optimal design sense. Some attempts on finite element modelling and simulation of the CDF were conducted using relatively simple models in literature and the research was still not sufficient enough for optimal design of a typical CDF for UHSS. Therefore two numerical models of Chain-die Forming process are developed in this study, including a) one having a set of rolls similar to roll forming but with a large radius, i.e., 20 meters; and b) the other one with dies and punch segments similar to a typical CDF machine. As a case study, to form a 60° channel with single pass was conducted using these two devised models for a comparison. The obtained numerical results clearly show the CDF could generate less residual stress, low strain and small springback of a single pass for the 60° UHSS channel. The design analysis procedure proposed in this study could greatly help the mechanical designers to devise a cost-effective and reliable CDF process for forming UHSS.

A numerical analysis on forming limits during spiral and concentric single point incremental forming

NASA Astrophysics Data System (ADS)

Gipiela, M. L.; Amauri, V.; Nikhare, C.; Marcondes, P. V. P.

2017-01-01

Sheet metal forming is one of the major manufacturing industries, which are building numerous parts for aerospace, automotive and medical industry. Due to the high demand in vehicle industry and environmental regulations on less fuel consumption on other hand, researchers are innovating new methods to build these parts with energy efficient sheet metal forming process instead of conventionally used punch and die to form the parts to achieve the lightweight parts. One of the most recognized manufacturing process in this category is Single Point Incremental Forming (SPIF). SPIF is the die-less sheet metal forming process in which the single point tool incrementally forces any single point of sheet metal at any process time to plastic deformation zone. In the present work, finite element method (FEM) is applied to analyze the forming limits of high strength low alloy steel formed by single point incremental forming (SPIF) by spiral and concentric tool path. SPIF numerical simulations were model with 24 and 29 mm cup depth, and the results were compare with Nakajima results obtained by experiments and FEM. It was found that the cup formed with Nakajima tool failed at 24 mm while cups formed by SPIF surpassed the limit for both depths with both profiles. It was also notice that the strain achieved in concentric profile are lower than that in spiral profile.

Examining leisure event opportunities of Isle Royale National Park: bridging the gap between social process and spatial form

Treesearch

Chad D. Pierskalla; Dorothy H. Anderson; David W. Lime

2000-01-01

To manage various recreation opportunities, managers and planners must consider the spatial and temporal scale of social process when identifying opportunities on base maps. However, analyses of social process and spatial form are often treated as two distinct approaches--sociological and geographical approaches. A sociologist might control for spatial form by adopting...

Testing single point incremental forming molds for thermoforming operations

NASA Astrophysics Data System (ADS)

Afonso, Daniel; de Sousa, Ricardo Alves; Torcato, Ricardo

2016-10-01

Low pressure polymer processing processes as thermoforming or rotational molding use much simpler molds then high pressure processes like injection. However, despite the low forces involved with the process, molds manufacturing for this operations is still a very material, energy and time consuming operation. The goal of the research is to develop and validate a method for manufacturing plastically formed sheets metal molds by single point incremental forming (SPIF) operation for thermoforming operation. Stewart platform based SPIF machines allow the forming of thick metal sheets, granting the required structural stiffness for the mold surface, and keeping the short lead time manufacture and low thermal inertia.

Melt-processed polymeric cellular dosage forms for immediate drug release.

PubMed

Blaesi, Aron H; Saka, Nannaji

2015-12-28

The present immediate-release solid dosage forms, such as the oral tablets and capsules, comprise granular matrices. While effective in releasing the drug rapidly, they are fraught with difficulties inherent in processing particulate matter. By contrast, liquid-based processes would be far more predictable; but the standard cast microstructures are unsuited for immediate-release because they resist fluid percolation and penetration. In this article, we introduce cellular dosage forms that can be readily prepared from polymeric melts by incorporating the nucleation, growth, and coalescence of microscopic gas bubbles in a molding process. We show that the cell topology and formulation of such cellular structures can be engineered to reduce the length-scale of the mass-transfer step, which determines the time of drug release, from as large as the dosage form itself to as small as the thickness of the cell wall. This allows the cellular dosage forms to achieve drug release rates over an order of magnitude faster compared with those of cast matrices, spanning the entire spectrum of immediate-release and beyond. The melt-processed polymeric cellular dosage forms enable predictive design of immediate-release solid dosage forms by tailoring microstructures, and could be manufactured efficiently in a single step.

Development of the Gliding Hole of the Dynamics Compression Plate

NASA Astrophysics Data System (ADS)

Salim, U. A.; Suyitno; Magetsari, R.; Mahardika, M.

2017-02-01

The gliding hole of the dynamics compression plate is designed to facilitate relative movement of pedicle screw during surgery application. The gliding hole shape is then geometrically complex. The gliding hole manufactured using machining processes used to employ ball-nose cutting tool. Then, production cost is expensive due to long production time. This study proposed to increase productivity of DCP products by introducing forming process (cold forming). The forming process used to involve any press tool devices. In the closed die forming press tool is designed with little allowance, then work-pieces is trapped in the mould after forming. Therefore, it is very important to determine hole geometry and dimensions of raw material in order to success on forming process. This study optimized the hole sizes with both geometry analytics and experiments. The success of the forming process was performed by increasing the holes size on the raw materials. The holes size need to be prepared is diameter of 5.5 mm with a length of 11.4 mm for the plate thickness 3 mm and diameter of 6 mm with a length of 12.5 mm for the plate thickness 4 mm.

The influence of differential processing of procathepsin H on its aminopeptidase activity, secretion and subcellular localization in human cell lines.

PubMed

Rojnik, Matija; Jevnikar, Zala R; Doljak, Bojan; Turk, Samo; Zidar, Nace; Kos, Janko

2012-10-01

Cathepsin H is a unique member of the cysteine cathepsins that acts primarily as an aminopeptidase. Like other cysteine cathepsins, it is synthesized as an inactive precursor and activated by proteolytic removal of its propeptide. Here we demonstrate that, in human cells, the processing of the propeptide is an autocatalytic, multistep process proceeding from an inactive 41kDa pro-form, through a 30kDa intermediate form, to the 28kDa mature form. Tyr87P and Gly90P were identified as the two major endopeptidase cleavage sites, converting the 30kDa form into the mature 28kDa form. The level of processing differs significantly in different human cell lines. In monocyte-derived macrophages U937 and prostate cancer cells PC-3, the 28kDa form is predominant, whereas in osteoblasts HOS the processing from the 30kDa form to the 28kDa form is significantly lower. The aminopeptidase activity of the enzyme and its subcellular localization are independent of the product, however the 30kDa form was not secreted in HOS cells. The activity of the resulting cathepsin H in U937 cells was significantly lower than that in HOS cells, presumably due to the high levels of endogenous cysteine protease inhibitor cystatin F present specifically in this cell line. These results provide an insight into the dependence of human cathepsin H processing and regulation on cell type. Copyright © 2012 Elsevier GmbH. All rights reserved.

Rubber pad forming - Efficient approach for the manufacturing of complex structured sheet metal blanks for food industry

NASA Astrophysics Data System (ADS)

Spoelstra, Paul; Djakow, Eugen; Homberg, Werner

2017-10-01

The production of complex organic shapes in sheet metals is gaining more importance in the food industry due to increasing functional and hygienic demands. Hence it is necessary to produce parts with complex geometries promoting cleanability and general sanitation leading to improvement of food safety. In this context, and especially when stainless steel has to be formed into highly complex geometries while maintaining desired surface properties, it is inevitable that alternative manufacturing processes will need to be used which meet these requirements. Rubber pad forming offers high potential when it comes to shaping complex parts with excellent surface quality, with virtually no tool marks and scratches. Especially in cases where only small series are to be produced, rubber pad forming processes offers both technological and economic advantages. Due to the flexible punch, variation in metal thickness can be used with the same forming tool. The investments to set-up Rubber pad forming is low in comparison to conventional sheet metal forming processes. The process facilitates production of shallow sheet metal parts with complex contours and bends. Different bending sequences in a multiple tool set-up can also be conducted. The planned contribution thus describes a brief overview of the rubber pad technology. It shows the prototype rubber pad forming machine which can be used to perform complex part geometries made from stainless steel (1.4301). Based on an analysis of the already existing systems and new machines for rubber pad forming processes, together with their process properties, influencing variables and areas of application, some relevant parts for the food industry are presented.

Mechanical Properties and Microstructure of High-Strength Steel Controlled by Hot Stamping Process

NASA Astrophysics Data System (ADS)

Ou, Hang; Zhang, Xu; Xu, Junrui; Li, Guangyao; Cui, Junjia

2018-03-01

A novel design and manufacturing method, dubbed "precast," of the cooling system and tools for a hot forming process was proposed in this paper. The integrated structures of the punch and blank holder were determined by analyzing the bending and reverse-bending deformation of the forming parts. The desired crashworthiness performance of an automotive front bumper constructed with this process was obtained by a tailored phase transformation, which generated martensite-bainite in the middle and full martensite transformation in the corner areas. Varying cooling effects in the formed parts caused the highest temperature to be located in the bottom and the lowest on the end of the formed parts. Moreover, the microstructural distributions demonstrated that the bottom possessed a relatively lower content of martensite, while, conversely, the end possessed a higher content. This was precisely the most desired phase distributions for the hot formed parts. For the six-process cycle stamping, the temperatures reached a stable status after an initial rapid increase in the first three process cycles. The microstructural results verified the feasibility of the hot forming tools under multiprocess cycles.

Incremental electrohydraulic forming - A new approach for the manufacture of structured multifunctional sheet metal blanks

NASA Astrophysics Data System (ADS)

Djakow, Eugen; Springer, Robert; Homberg, Werner; Piper, Mark; Tran, Julian; Zibart, Alexander; Kenig, Eugeny

2017-10-01

Electrohydraulic Forming (EHF) processes permit the production of complex, sharp-edged geometries even when high-strength materials are used. Unfortunately, the forming zone is often limited as compared to other sheet metal forming processes. The use of a special industrial-robot-based tool setup and an incremental process strategy could provide a promising solution for this problem. This paper describes such an innovative approach using an electrohydraulic incremental forming machine, which can be employed to manufacture the large multifunctional and complex part geometries in steel, aluminium, magnesium and reinforced plastic that are employed in lightweight constructions or heating elements.

Development of a beam builder for automatic fabrication of large composite space structures

NASA Technical Reports Server (NTRS)

Bodle, J. G.

1979-01-01

The composite material beam builder which will produce triangular beams from pre-consolidated graphite/glass/thermoplastic composite material through automated mechanical processes is presented, side member storage, feed and positioning, ultrasonic welding, and beam cutoff are formed. Each process lends itself to modular subsystem development. Initial development is concentrated on the key processes for roll forming and ultrasonic welding composite thermoplastic materials. The construction and test of an experimental roll forming machine and ultrasonic welding process control techniques are described.

Transfer-of-Training Effects in Processing Instruction: The Role of Form-Related Explicit Information

ERIC Educational Resources Information Center

White, Justin P.; DeMil, Andrew J.

2013-01-01

This study compares the effects of processing instruction (PI), structured input (SI), and form-related explicit information (FREI) on a primary target form (i.e., third-person Spanish accusative clitics) and on a secondary form (i.e., third-person Spanish dative clitics). Participants included 151 adult learners enrolled in a beginning-level…

Process and structures for fabrication of solar cells with laser ablation steps to form contact holes

DOEpatents

Harley, Gabriel; Smith, David D; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

2013-11-19

Contact holes of solar cells are formed by laser ablation to accomodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thickness.

7 CFR 3430.12 - Requests for applications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... applicable. (13) Directions for obtaining additional requests for applications and application forms. (14) Information about how to obtain application forms and the instructions for completing such forms. (15... of the application evaluation Process. (17) Specific evaluation criteria used in the review Process...

Set of Criteria for Efficiency of the Process Forming the Answers to Multiple-Choice Test Items

ERIC Educational Resources Information Center

Rybanov, Alexander Aleksandrovich

2013-01-01

Is offered the set of criteria for assessing efficiency of the process forming the answers to multiple-choice test items. To increase accuracy of computer-assisted testing results, it is suggested to assess dynamics of the process of forming the final answer using the following factors: loss of time factor and correct choice factor. The model…

17 CFR 249.508 - Form 8-M, consent to service of process by a corporation which is a nonresident broker-dealer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... to service of process by a corporation which is a nonresident broker-dealer. This form shall be filed... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 8-M, consent to service of process by a corporation which is a nonresident broker-dealer. 249.508 Section 249.508 Commodity...

Geometrical accuracy improvement in flexible roll forming lines

NASA Astrophysics Data System (ADS)

Larrañaga, J.; Berner, S.; Galdos, L.; Groche, P.

2011-01-01

The general interest to produce profiles with variable cross section in a cost-effective way has increased in the last few years. The flexible roll forming process allows producing profiles with variable cross section lengthwise in a continuous way. Until now, only a few flexible roll forming lines were developed and built up. Apart from the flange wrinkling along the transition zone of u-profiles with variable cross section, the process limits have not been investigated and solutions for shape deviations are unknown. During the PROFOM project a flexible roll forming machine has been developed with the objective of producing high technological components for automotive body structures. In order to investigate the limits of the process, different profile geometries and steel grades including high strength steels have been applied. During the first experimental tests, several errors have been identified, as a result of the complex stress states generated during the forming process. In order to improve the accuracy of the target profiles and to meet the tolerance demands of the automotive industry, a thermo-mechanical solution has been proposed. Additional mechanical devices, supporting flexible the roll forming process, have been implemented in the roll forming line together with local heating techniques. The combination of both methods shows a significant increase of the accuracy. In the present investigation, the experimental results of the validation process are presented.

Forming Refractory Insulation On Copper Wire

NASA Technical Reports Server (NTRS)

Setlock, J.; Roberts, G.

1995-01-01

Alternative insulating process forms flexible coat of uncured refractory insulating material on copper wire. Coated wire formed into coil or other complex shape. Wire-coating apparatus forms "green" coat on copper wire. After wire coiled, heating converts "green" coat to refractory electrical insulator. When cured to final brittle form, insulating material withstands temperatures above melting temperature of wire. Process used to make coils for motors, solenoids, and other electrical devices to be operated at high temperatures.

Light extinction method for diagnostics of particles sizes formed in magnetic field

NASA Astrophysics Data System (ADS)

Myshkin, Vyacheslav; Izhoykin, Dmitry; Grigoriev, Alexander; Gamov, Denis; Leonteva, Daria

2018-03-01

The results of laser diagnostics of dispersed particles formed upon cooling of Zn vapor are presented. The radiation attenuation in the wavelength range 420-630 nm with a step of 0.3 nm was registered. The attenuation coefficients spectral dependence was processed using known algorithms for integral equation solving. The 10 groups of 8 attenuation coefficients were formed. Each group was processed taking with considering of previous decisions. After processing of the 10th group of data, calculations were repeated from the first one. Data of the particles sizes formed in a magnetic field of 0, 44 and 76 mT are given. A model of physical processes in a magnetic field is discussed.

The effect of additive geometry on the integration of secondary elements during Friction Stir Processing

NASA Astrophysics Data System (ADS)

Zens, A.; Gnedel, M.; Zaeh, M. F.; Haider, F.

2018-06-01

Friction Stir Processing (FSP) can be used to locally modify properties in materials such as aluminium. This may be used, for example, to produce a fine microstructure or to integrate secondary elements into the base material. The purpose of this work is to examine the effect of the properties of the metal additives on the resulting material distribution in the processed region. For this, commercially pure iron and copper were integrated into an EN AW-1050 aluminium base material using FSP. Iron in the form of powder, wire and foil as well as copper in powder form were assessed. The various additive forms represent materials with differing surface-to-volume ratios as well as varying dispersion characteristics in the processing zone. The processing parameters for each additive form remained constant; however, two- and four-pass FSP processes were conducted. The results of CT analysis proved especially insightful regarding the spatial distribution of the various additive form within the workpiece. As expected, the powder additive was most widely distributed within the welding zone. Micro-hardness mappings showed that the powder additive contributed to the hardness within the weld nugget in comparison to the processed material without secondary elements.

8 CFR 204.3 - Orphan cases under section 101(b)(1)(F) of the Act (non-Convention cases).

Code of Federal Regulations, 2013 CFR

2013-01-01

... advanced processing application (or the advanced processing application concurrently with the orphan... home study preparer and/or fingerprint check. Advanced processing application means Form I-600A (Application for Advanced Processing of Orphan Petition) completed in accordance with the form's instructions...

8 CFR 204.3 - Orphan cases under section 101(b)(1)(F) of the Act (non-Convention cases).

Code of Federal Regulations, 2010 CFR

2010-01-01

... advanced processing application (or the advanced processing application concurrently with the orphan... home study preparer and/or fingerprint check. Advanced processing application means Form I-600A (Application for Advanced Processing of Orphan Petition) completed in accordance with the form's instructions...

8 CFR 204.3 - Orphan cases under section 101(b)(1)(F) of the Act (non-Convention cases).

Code of Federal Regulations, 2014 CFR

2014-01-01

... advanced processing application (or the advanced processing application concurrently with the orphan... home study preparer and/or fingerprint check. Advanced processing application means Form I-600A (Application for Advanced Processing of Orphan Petition) completed in accordance with the form's instructions...

8 CFR 204.3 - Orphan cases under section 101(b)(1)(F) of the Act (non-Convention cases).

Code of Federal Regulations, 2011 CFR

2011-01-01

... advanced processing application (or the advanced processing application concurrently with the orphan... home study preparer and/or fingerprint check. Advanced processing application means Form I-600A (Application for Advanced Processing of Orphan Petition) completed in accordance with the form's instructions...

8 CFR 204.3 - Orphan cases under section 101(b)(1)(F) of the Act (non-Convention cases).

Code of Federal Regulations, 2012 CFR

2012-01-01

... advanced processing application (or the advanced processing application concurrently with the orphan... home study preparer and/or fingerprint check. Advanced processing application means Form I-600A (Application for Advanced Processing of Orphan Petition) completed in accordance with the form's instructions...

78 FR 310 - Draft Revision of Guidance for Industry on Providing Regulatory Submissions in Electronic Format...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-03

...ApprovalProcess/FormsSubmissionRequirements/ElectronicSubmissions/ucm253101.htm , http://www.regulations.../Drugs/DevelopmentApprovalProcess/FormsSubmissionRequirements/ElectronicSubmissions/ucm253101.htm , http...), in a format that FDA can process, review, and archive. Currently, the Agency can process, review, and...

A comparison of form processing involved in the perception of biological and nonbiological movements

PubMed Central

Thurman, Steven M.; Lu, Hongjing

2016-01-01

Although there is evidence for specialization in the human brain for processing biological motion per se, few studies have directly examined the specialization of form processing in biological motion perception. The current study was designed to systematically compare form processing in perception of biological (human walkers) to nonbiological (rotating squares) stimuli. Dynamic form-based stimuli were constructed with conflicting form cues (position and orientation), such that the objects were perceived to be moving ambiguously in two directions at once. In Experiment 1, we used the classification image technique to examine how local form cues are integrated across space and time in a bottom-up manner. By comparing with a Bayesian observer model that embodies generic principles of form analysis (e.g., template matching) and integrates form information according to cue reliability, we found that human observers employ domain-general processes to recognize both human actions and nonbiological object movements. Experiments 2 and 3 found differential top-down effects of spatial context on perception of biological and nonbiological forms. When a background does not involve social information, observers are biased to perceive foreground object movements in the direction opposite to surrounding motion. However, when a background involves social cues, such as a crowd of similar objects, perception is biased toward the same direction as the crowd for biological walking stimuli, but not for rotating nonbiological stimuli. The model provided an accurate account of top-down modulations by adjusting the prior probabilities associated with the internal templates, demonstrating the power and flexibility of the Bayesian approach for visual form perception. PMID:26746875

Improving reliability of a residency interview process.

PubMed

Peeters, Michael J; Serres, Michelle L; Gundrum, Todd E

2013-10-14

To improve the reliability and discrimination of a pharmacy resident interview evaluation form, and thereby improve the reliability of the interview process. In phase 1 of the study, authors used a Many-Facet Rasch Measurement model to optimize an existing evaluation form for reliability and discrimination. In phase 2, interviewer pairs used the modified evaluation form within 4 separate interview stations. In phase 3, 8 interviewers individually-evaluated each candidate in one-on-one interviews. In phase 1, the evaluation form had a reliability of 0.98 with person separation of 6.56; reproducibly, the form separated applicants into 6 distinct groups. Using that form in phase 2 and 3, our largest variation source was candidates, while content specificity was the next largest variation source. The phase 2 g-coefficient was 0.787, while confirmatory phase 3 was 0.922. Process reliability improved with more stations despite fewer interviewers per station-impact of content specificity was greatly reduced with more interview stations. A more reliable, discriminating evaluation form was developed to evaluate candidates during resident interviews, and a process was designed that reduced the impact from content specificity.

17 CFR 249.507 - Form 7-M, consent to service of process by an individual nonresident broker-dealer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 7-M, consent to service of process by an individual nonresident broker-dealer. 249.507 Section 249.507 Commodity and... Forms for Statements Made in Connection With Exempt Tender Offers § 249.507 Form 7-M, consent to service...

17 CFR 249.509 - Form 9-M, consent to service of process by a partnership nonresident broker-dealer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 9-M, consent to service of process by a partnership nonresident broker-dealer. 249.509 Section 249.509 Commodity and... Forms for Statements Made in Connection With Exempt Tender Offers § 249.509 Form 9-M, consent to service...

Vitality Forms Processing in the Insula during Action Observation: A Multivoxel Pattern Analysis.

PubMed

Di Cesare, Giuseppe; Valente, Giancarlo; Di Dio, Cinzia; Ruffaldi, Emanuele; Bergamasco, Massimo; Goebel, Rainer; Rizzolatti, Giacomo

2016-01-01

Observing the style of an action done by others allows the observer to understand the cognitive state of the agent. This information has been defined by Stern "vitality forms". Previous experiments showed that the dorso-central insula is selectively active both during vitality form observation and execution. In the present study, we presented participants with videos showing hand actions performed with different velocities and asked them to judge either their vitality form (gentle, neutral, rude) or their velocity (slow, medium, fast). The aim of the present study was to assess, using multi-voxel pattern analysis, whether vitality forms and velocities of observed goal-directed actions are differentially processed in the insula, and more specifically whether action velocity is encoded per se or it is an element that triggers neural populations of the insula encoding the vitality form. The results showed that, consistently across subjects, in the dorso-central sector of the insula there were voxels selectively tuned to vitality forms, while voxel tuned to velocity were rare. These results indicate that the dorso-central insula, which previous data showed to be involved in the vitality form processing, contains voxels specific for the action style processing.

Processing of zero-derived words in English: an fMRI investigation.

PubMed

Pliatsikas, Christos; Wheeldon, Linda; Lahiri, Aditi; Hansen, Peter C

2014-01-01

Derivational morphological processes allow us to create new words (e.g. punish (V) to noun (N) punishment) from base forms. The number of steps from the basic units to derived words often varies (e.g., nationalitybridge-V) i.e., zero-derivation (Aronoff, 1980). We compared the processing of one-step (soaking

17 CFR 249.510 - Form 10-M, consent to service of process by a nonresident general partner of a broker-dealer firm.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., consent to service of process by a nonresident general partner of a broker-dealer firm. This form shall be... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form 10-M, consent to service of process by a nonresident general partner of a broker-dealer firm. 249.510 Section 249.510...

Three Dimensional Forming Simulation of the Shielded Slot Plate for the MCFC Using a Ductile Fracture Criterion

NASA Astrophysics Data System (ADS)

Lee, C. H.; Yang, D. Y.; Lee, S. R.; Chang, I. G.; Lee, T. W.

2011-08-01

The shielded slot plate, which has a sheared corrugated trapezoidal pattern, is a component of the metallic bipolar plate for the molten carbonate fuel cell (MCFC). In order to increase the efficiency of the fuel cell, the unit cell of the shielded slot plate should have a relatively large upper area. Additionally, defects from the forming process should be minimized. In order to simulate the slitting process, whereby sheared corrugated patterns are formed, ductile fracture criteria based on the histories of stress and strain are employed. The user material subroutine VUMAT is employed for implementation of the material and ductile fracture criteria in the commercial FEM software ABAQUS. The variables of the ductile fracture criteria were determined by comparing the simulation results and the experimental results of the tension test and the shearing test. Parametric studies were conducted to determine the critical value of the ductile fracture criterion. Employing these ductile fracture criteria, the three dimensional forming process of the shielded slot plate was numerically simulated. The effects of the slitting process in the forming process of the shielded slot plate were analyzed through a FEM simulation and experimental studies. Finally, experiments involving microscopic and macroscopic observations were conducted to verify the numerical simulations of the 3-step forming process.

Method for Fabricating Composite Structures Including Continuous Press Forming and Pultrusion Processing

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

1995-01-01

A method for fabricating composite structures at a low-cost, moderate-to-high production rate is disclosed. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply, and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform, and debulking the partially debulked preform to form a netshape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length, and electron-beam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates, resulting in lower cost and high structural performance.

Process for forming transparent aerogel insulating arrays

DOEpatents

Tewari, Param H.; Hunt, Arlon J.

1986-01-01

An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO.sub.2, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO.sub.2, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40.degree. C. instead of at about 270.degree. C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementry particles or cosmic rays.

Insertion and assembly of the precursor of subunit II into the photosystem I complex may precede its processing.

PubMed Central

Cohen, Y; Steppuhn, J; Herrmann, R G; Yalovsky, S; Nechushtai, R

1992-01-01

The biogenesis and assembly of subunit II of photosystem I (PSI) (psaD gene product) were studied and characterized. The precursor and the mature form were produced in vitro and incubated with intact plastids or isolated thylakoids. Following import of the precursor into isolated plastids, mostly the mature form of subunit II was found in the thylakoids. However, when the processing activity was inhibited only the precursor form was present in the membranes. The precursor was processed by a stromal peptidase and processing could occur before or after insertion of the precursor into the thylakoids. Following insertion into isolated thylakoids, both the precursor and the mature form of subunit II were confined to the PSI complex. Insertion of the mature form of subunit II was much less efficient than that of the precursor. Kinetic studies showed that the precursor was inserted into the membrane. Only at a later stage, the mature form began to accumulate. These results suggest that in vivo the precursor of subunit II is inserted and embedded in the thylakoids, as part of the PSI complex. Only later, it is processed to the mature form through the action of a stromal peptidase. Images PMID:1740118

Formability behavior studies on CP-Al sheets processed through the helical tool path of incremental forming process

NASA Astrophysics Data System (ADS)

Markanday, H.; Nagarajan, D.

2018-02-01

Incremental sheet forming (ISF) is a novel die-less sheet metal forming process, which can produce components directly from the CAD geometry using a CNC milling machine at less production time and cost. The formability of the sheet material used is greatly affected by the process parameters involved and tool path adopted, and the present study is aimed to investigate the influence of different process parameter values using the helical tool path strategy on the formability of a commercial pure Al and to achieve maximum formability in the material. ISF experiments for producing an 80 mm diameter axisymmetric dome were carried out on 2 mm thickness commercially pure Al sheets for different tool speeds and feed rates in a CNC milling machine with a 10 mm hemispherical forming tool. The obtained parts were analyzed for springback, amount of thinning and maximum forming depth. The results showed that when the tool speed was increased by keeping the feed rate constant, the forming depth and thinning were also increased. On contrary, when the feed rate was increased by keeping the tool speed constant, the forming depth and thinning were decreased. Springback was found to be higher when the feed rate was increased rather than the tool speed was increased.

Process for forming transparent aerogel insulating arrays

DOEpatents

Tewari, P.H.; Hunt, A.J.

1985-09-04

An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO/sub 2/, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO/sub 2/, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40/sup 0/C instead of at about 270/sup 0/C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementary particles or cosmic rays.

Solventless visible light-curable coating: I. Critical formulation and processing parameters.

PubMed

Bose, Sagarika; Bogner, Robin H

2010-06-30

Film coating is generally accomplished by spraying polymers dissolved in solvents onto a cascading bed of tablets. The limitations associated with the use of solvents (both aqueous and organic) can be overcome by the use of solventless coating technologies. In this proposed solventless photocurable film coating system, each layer of coating onto the pellets (non-pareil beads) was formed using liquid photocurable monomer, powdered pore-forming agents, photosensitizers and photoinitiators in a mini-coating pan and later cured by visible light. Yield, coating efficiency, variation in color, diameter and roundness were determined for each batch to evaluate process efficiency and coating quality. It was found that the ratio (S/L ratio) of the amount of solid (S) pore-forming agent to volume of liquid (L) monomer, particle size and type of the pore-forming agent, concentration of initiator, and total exposure (light intensity x exposure time) of light were critical formulation and processing parameters for the process. Using lactose as a pore-forming agent, an optimum ratio of pore-forming agent to photocurable polymer was 1.8-3.0 to achieve good process efficiency and uniformity. The ratio was sensitive to particle size and type of pore-forming agent. 2010 Elsevier B.V. All rights reserved.

Near-net-shape manufacturing: Spray-formed metal matrix composites and tooling

NASA Technical Reports Server (NTRS)

Mchugh, Kevin M.

1994-01-01

Spray forming is a materials processing technology in which a bulk liquid metal is converted to a spray of fine droplets and deposited onto a substrate or pattern to form a near-net-shape solid. The technology offers unique opportunities for simplifying materials processing without sacrificing, and oftentimes substantially improving, product quality. Spray forming can be performed with a wide range of metals and nonmetals, and offers property improvements resulting from rapid solidification (e.g. refined microstructures, extended solid solubilities and reduced segregation). Economic benefits result from process simplification and the elimination of unit operations. The Idaho National Engineering Laboratory is developing a unique spray-forming method, the Controlled Aspiration Process (CAP), to produce near-net-shape solids and coatings of metals, polymers, and composite materials. Results from two spray-accompanying technical and economic benefits. These programs involved spray forming aluminum strip reinforced with SiC particulate, and the production of tooling, such as injection molds and dies, using low-melting-point metals.

A novel methodology for in-process monitoring of flow forming

NASA Astrophysics Data System (ADS)

Appleby, Andrew; Conway, Alastair; Ion, William

2017-10-01

Flow forming (FF) is an incremental cold working process with near-net-shape forming capability. Failures by fracture due to high deformation can be unexpected and sometimes catastrophic, causing tool damage. If process failures can be identified in real time, an automatic cut-out could prevent costly tool damage. Sound and vibration monitoring is well established and commercially viable in the machining sector to detect current and incipient process failures, but not for FF. A broad-frequency microphone was used to record the sound signature of the manufacturing cycle for a series of FF parts. Parts were flow formed using single and multiple passes, and flaws were introduced into some of the parts to simulate the presence of spontaneously initiated cracks. The results show that this methodology is capable of identifying both introduced defects and spontaneous failures during flow forming. Further investigation is needed to categorise and identify different modes of failure and identify further potential applications in rotary forming.

The dynamic lift of developmental process.

PubMed

Smith, Linda B; Breazeal, Cynthia

2007-01-01

What are the essential properties of human intelligence, currently unparalleled in its power relative to other biological forms and relative to artificial forms of intelligence? We suggest that answering this question depends critically on understanding developmental process. This paper considers three principles potentially essential to building human-like intelligence: the heterogeneity of the component processes, the embedding of development in a social world, and developmental processes that change the cognitive system as a function of the history of soft-assemblies of these heterogeneous processes in specific tasks. The paper uses examples from human development and from developmental robotics to show how these processes also may underlie biological intelligence and enable us to generate more advanced forms of artificial intelligence.

Laser processing of solar cells with anti-reflective coating

DOEpatents

Harley, Gabriel; Smith, David D.; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

2016-02-16

Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

17 CFR 249.250 - Form F-X, for appointment of agent for service of process by issuers registering securities on...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form F-X, for appointment of... F-X, for appointment of agent for service of process by issuers registering securities on Form F-8... registered on Form F-7 (§ 249.37 of this chapter), F-8, F-9, F-10 or F-80. Form F-X shall be filed with the...

17 CFR 249.250 - Form F-X, for appointment of agent for service of process by issuers registering securities on...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Form F-X, for appointment of... F-X, for appointment of agent for service of process by issuers registering securities on Form F-8... registered on Form F-7 (§ 249.37 of this chapter), F-8, F-9, F-10 or F-80. Form F-X shall be filed with the...

Screening and Characterization of Hydrate Forms of T-3256336, a Novel Inhibitor of Apoptosis (IAP) Protein Antagonist.

PubMed

Takeuchi, Shoko; Kojima, Takashi; Hashimoto, Kentaro; Saito, Bunnai; Sumi, Hiroyuki; Ishikawa, Tomoyasu; Ikeda, Yukihiro

2015-01-01

Different crystal packing of hydrates from anhydrate crystals leads to different physical properties, such as solubility and stability. Investigation of the potential of varied hydrate formation, and understanding the stability in an anhydrous/hydrate system, are crucial to prevent an undesired transition during the manufacturing process and storage. Only one anhydrous form of T-3256336, a novel inhibitor of apoptosis (IAP) protein antagonist, was discovered during synthesis, and no hydrate form has been identified. In this study, we conducted hydrate screening such as dynamic water vapor sorption/desorption (DVS), and the slurry experiment, and characterized the solid-state properties of anhydrous/hydrate forms to determine the most desirable crystalline form for development. New hydrate forms, both mono-hydrate and hemi-hydrate forms, were discovered as a result of this hydrate screening. The characterization of two new hydrate forms was conducted, and the anhydrous form was determined to be the most desirable development form of T-3256336 in terms of solid-state stability. In addition, the stability of the anhydrous form was investigated using the water content and temperature controlled slurry experiment to obtain the desirable crystal form in the crystallization process. The water content regions of the stable phase of the desired form, the anhydrous form, were identified for the cooling crystallization process.

Process for catalytically oxidizing cycloolefins, particularly cyclohexene

DOEpatents

Mizuno, Noritaka; Lyon, David K.; Finke, Richard G.

1993-01-01

This invention is a process for catalytically oxidizing cycloolefins, particularly cyclohexenes, to form a variety of oxygenates. The catalyst used in the process is a covalently bonded iridium-heteropolyanion species. The process uses the catalyst in conjunction with a gaseous oxygen containing gas to form 2-cyclohexen-1-ol and also 2-cyclohexen-1-one.

Friction spinning - Twist phenomena and the capability of influencing them

NASA Astrophysics Data System (ADS)

Lossen, Benjamin; Homberg, Werner

2016-10-01

The friction spinning process can be allocated to the incremental forming techniques. The process consists of process elements from both metal spinning and friction welding. The selective combination of process elements from these two processes results in the integration of friction sub-processes in a spinning process. This implies self-induced heat generation with the possibility of manufacturing functionally graded parts from tube and sheets. Compared with conventional spinning processes, this in-process heat treatment permits the extension of existing forming limits and also the production of more complex geometries. Furthermore, the defined adjustment of part properties like strength, grain size/orientation and surface conditions can be achieved through the appropriate process parameter settings and consequently by setting a specific temperature profile in combination with the degree of deformation. The results presented from tube forming start with an investigation into the resulting twist phenomena in flange processing. In this way, the influence of the main parameters, such as rotation speed, feed rate, forming paths and tool friction surface, and their effects on temperature, forces and finally the twist behavior are analyzed. Following this, the significant correlations with the parameters and a new process strategy are set out in order to visualize the possibility of achieving a defined grain texture orientation.

Method for Fabricating Composite Structures Using Continuous Press Forming

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

1997-01-01

A method for fabricating composite structures at a low-cost. moderate-to-high production rate. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform and debulking the partially debulked preform to form a net-shape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length and electron-beam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates. resulting in lower cost and high structural performance.

Pharmaceutical approaches to preparing pelletized dosage forms using the extrusion-spheronization process.

PubMed

Trivedi, Namrata R; Rajan, Maria Gerald; Johnson, James R; Shukla, Atul J

2007-01-01

Pelletized dosage forms date back to the 1950s, when the first product was introduced to the market. Since then, these dosage forms have gained considerable popularity because of their distinct advantages, such as ease of capsule filling because of better flow properties of the spherical pellets; enhancement of drug dissolution; ease of coating; sustained, controlled, or site-specific delivery of the drug from coated pellets; uniform packing; even distribution in the GI tract; and less GI irritation. Pelletized dosage forms can be prepared by a number of techniques, including drug layering on nonpareil sugar or microcrystalline cellulose beads, spray drying, spray congealing, rotogranulation, hot-melt extrusion, and spheronization of low melting materials or extrusion-spheronization of a wet mass. This review discusses recent developments in the pharmaceutical approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process over the last decade. The review is divided into three parts: the first part discusses the extrusion-spheronization process, the second part discusses the effect of varying formulation and process parameters on the properties of the pellets, and the last part discusses the different approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process.

Explicit and Implicit Emotion Regulation: A Dual-Process Framework

PubMed Central

Gyurak, Anett; Gross, James J.; Etkin, Amit

2012-01-01

It is widely acknowledged that emotions can be regulated in an astonishing variety of ways. Most research to date has focused on explicit (effortful) forms of emotion regulation. However, there is growing research interest in implicit (automatic) forms of emotion regulation. To organize emerging findings, we present a dual-process framework that integrates explicit and implicit forms of emotion regulation, and argue that both forms of regulation are necessary for well-being. In the first section of this review, we provide a broad overview of the construct of emotion regulation, with an emphasis on explicit and implicit processes. In the second section, we focus on explicit emotion regulation, considering both neural mechanisms that are associated with these processes and their experiential and physiological consequences. In the third section, we turn to several forms of implicit emotion regulation, and integrate the burgeoning literature in this area. We conclude by outlining open questions and areas for future research. PMID:21432682

System and process for producing fuel with a methane thermochemical cycle

DOEpatents

Diver, Richard B.

2015-12-15

A thermochemical process and system for producing fuel are provided. The thermochemical process includes reducing an oxygenated-hydrocarbon to form an alkane and using the alkane in a reforming reaction as a reducing agent for water, a reducing agent for carbon dioxide, or a combination thereof. Another thermochemical process includes reducing a metal oxide to form a reduced metal oxide, reducing an oxygenated-hydrocarbon with the reduced metal oxide to form an alkane, and using the alkane in a reforming reaction as a reducing agent for water, a reducing agent for carbon dioxide, or a combination thereof. The system includes a reformer configured to perform a thermochemical process.

Process for forming epitaxial perovskite thin film layers using halide precursors

DOEpatents

Clem, Paul G.; Rodriguez, Mark A.; Voigt, James A.; Ashley, Carol S.

2001-01-01

A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

Process for making RF shielded cable connector assemblies and the products formed thereby

NASA Technical Reports Server (NTRS)

Fisher, A.; Clatterbuck, C. H. (Inventor)

1973-01-01

A process for making RF shielded cable connector assemblies and the resulting structures is described. The process basically consists of potting wires of a shielded cable between the cable shield and a connector housing to fill in, support, regidize, and insulate the individual wires contained in the cable. The formed potting is coated with an electrically conductive material so as to form an entirely encompassing adhering conductive path between the cable shield and the metallic connector housing. A protective jacket is thereby formed over the conductive coating between the cable shield and the connector housing.

Process for forming planarized films

DOEpatents

Pang, Stella W.; Horn, Mark W.

1991-01-01

A planarization process and apparatus which employs plasma-enhanced chemical vapor deposition (PECVD) to form plarnarization films of dielectric or conductive carbonaceous material on step-like substrates.

Computer Simulation of Material Flow in Warm-forming Bimetallic Components

NASA Astrophysics Data System (ADS)

Kong, T. F.; Chan, L. C.; Lee, T. C.

2007-05-01

Bimetallic components take advantage of two different metals or alloys so that their applicable performance, weight and cost can be optimized. However, since each material has its own flow properties and mechanical behaviour, heterogeneous material flows will occur during the bimetal forming process. Those controls of process parameters are relatively more complicated than forming single metals. Most previous studies in bimetal forming have focused mainly on cold forming, and less relevant information about the warm forming has been provided. Indeed, changes of temperature and heat transfer between two materials are the significant factors which can highly influence the success of the process. Therefore, this paper presents a study of the material flow in warm-forming bimetallic components using finite-element (FE) simulation in order to determine the suitable process parameters for attaining the complete die filling. A watch-case-like component made of stainless steel (AISI-316L) and aluminium alloy (AL-6063) was used as the example. The warm-forming processes were simulated with the punch speeds V of 40, 80, and 120 mm/s and the initial temperatures of the stainless steel TiSS of 625, 675, 725, 775, 825, 875, 925, 975, and 1025 °C. The results showed that the AL-6063 flowed faster than the AISI-316L and so the incomplete die filling was only found in the AISI-316L region. A higher TiSS was recommended to avoid incomplete die filling. The reduction of V is also suggested because this can save the forming energy and prevent the damage of tooling. Eventually, with the experimental verification, the results from the simulation were in agreement with those of the experiments. On the basis of the results of this study, engineers can gain a better understanding of the material flow in warm-forming bimetallic components, and be able to determine more efficiently the punch speed and initial material temperature for the process.

FY16 Annual Accomplishments - Waste Form Development and Performance: Evaluation Of Ceramic Waste Forms - Comparison Of Hot Isostatic Pressed And Melt Processed Fabrication Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amoroso, J.; Dandeneau, C.

FY16 efforts were focused on direct comparison of multi-phase ceramic waste forms produced via melt processing and HIP methods. Based on promising waste form compositions previously devised at SRNL, simulant material was prepared at SRNL and a portion was sent to the Australian Nuclear Science and Technology Organization (ANSTO) for HIP treatments, while the remainder of the material was melt processed at SRNL. The microstructure, phase formation, elemental speciation, and leach behavior, and radiation stability of the fabricated ceramics was performed. In addition, melt-processed ceramics designed with different fractions of hollandite, zirconolite, perovskite, and pyrochlore phases were investigated. for performancemore » and properties.« less

BOOK REVIEW: Introduction to Computational Plasticity

NASA Astrophysics Data System (ADS)

Hartley, P.

2006-04-01

The use of computational modelling in all areas of science and engineering has in recent years escalated to the point where it underpins much of current research. However, the distinction must be made between computer systems in which no knowledge of the underlying computer technology or computational theory is required and those areas of research where the mastery of computational techniques is of great value, almost essential, for final year undergraduates or masters students planning to pursue a career in research. Such a field of research in the latter category is continuum mechanics, and in particular non-linear material behaviour, which is the core topic of this book. The focus of the book on computational plasticity embodies techniques of relevance not only to academic researchers, but also of interest to industrialists engaged in the production of components using bulk or sheet forming processes. Of particular interest is the guidance on how to create modules for use with the commercial system Abaqus for specific types of material behaviour. The book is in two parts, the first of which contains six chapters, starting with microplasticity, but predominantly on continuum plasticity. The first chapter on microplasticty gives a brief description of the grain structure of metals and the existence of slip systems within the grains. This provides an introduction to the concept of incompressibility during plastic deformation, the nature of plastic yield and the importance of the critically resolved shear stress on the slip planes (Schmid's law). Some knowledge of the notation commonly used to describe slip systems is assumed, which will be familiar to students of metallurgy, but anyone with a more general engineering background may need to undertake additional reading to understand the various descriptions. Any lack of knowledge in this area however, is of no disadvantage as it serves only as an introduction and the book moves on quickly to continuum plasticity. Chapter two introduces one of several yield criteria, that normally attributed to von Mises (though historians of mechanics might argue over who was first to develop the theory of yielding associated with strain energy density), and its two or three-dimensional representation as a yield surface. The expansion of the yield surface during plastic deformation, its translation due to kinematic hardening and the Bauschinger effect in reversed loading are described with a direct link to the material stress-strain curve. The assumption, that the increment of strain is normal to the yield surface, the normality principle, is introduced. Uniaxial loading of an elastic-plastic material is used as an example in which to develop expressions to describe increments in stress and strain. The full presentation of numerous expressions, tensors and matrices with a clear explanation of their development, is a recurring, and commendable, feature of the book, which provides an invaluable introduction for those new to the subject. The chapter moves on from time-independent behaviour to introduce viscoplasticity and creep. Chapter three takes the theories of deformation another stage further to consider the problems associated with large deformation in which an important concept is the separation of the phenomenon into material stretch and rotation. The latter is crucial to allow correct measures of strain and stress to be developed in which the effects of rigid body rotation do not contribute to these variables. Hence, the introduction of 'objective' measures for stress and strain. These are described with reference to deformation gradients, which are clearly explained; however, the introduction of displacement gradients passes with little comment, although velocity gradients appear later in the chapter. The interpretation of different strain measures, e.g. Green--Lagrange and Almansi, is covered briefly, followed by a description of the spin tensor and its use in developing the objective Jaumann rate of stress. It is tempting here to suggest that a more complete description should be given together with other measures of strain and stress, of which there are several, but there would be a danger of changing the book from an `introduction' to a more comprehensive text, and examples of such exist already. Chapter four begins the process of developing the plasticity theories into a form suitable for inclusion in the finite-element method. The starting point is Hamilton's principle for equilibrium of a dynamic system. A very brief introduction to the finite-element method is then given, followed by the finite-element equilibrium equations and a description of how they are incorporated into Hamilton's principle. A useful clarification is provided by comparing tensor notation and the form normally used in finite-element expressions, i.e. Voigt notation. The chapter concludes with a brief overview of implicit integration methods, i.e. tangent stiffness, initial tangent stiffness and Newton Raphson. Chapter five deals with the more specialized topic of implicit and explicit integration of von Mises plasticity. One of the techniques described is the radial-return method which ensures that the stresses at the end of an increment of deformation always lie on the expanded yield surface. Although this method guarantees a solution it may not always be the most accurate for large deformation, this is one area where reference to alternative methods would have been a helpful addition. Chapter six continues with further detail of how the plasticity models may be incorporated into finite-element codes, with particular reference to the Abaqus package and the use of user-defined subroutines, introduced via a `UMAT' subroutine. This completes part I of the book. Part II focuses on plasticity models, each chapter dealing with a particular process or material model. For example, chapter seven deals with superplasticity, chapter eight with porous plasticity, chapter nine with creep and chapter ten with cyclic plasticity, creep and TMF. Examples of deep drawing, forming of titanium metal-matrix composites and creep damage are provided, together with further guidelines on the use of Abaqus to model these processes. Overall, the book is organised in a very logical and readable form. The use of simple one-dimensional examples, with full descriptions of tensors and vectors throughout the book, is particularly useful. It provides a good introduction to the topic, covering much of the theory and with applications to give a good grounding that can be taken further with more comprehensive advanced texts. An excellent starting point for anyone involved in research in computational plasticity.

75 FR 38087 - Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-01

... Repatriation Reporting System, DD Form 2585, OMB Control Number 0704- 0334. Needs and Uses: This information... from the DD Form 2585 is entered into an automated system; a series of reports is accessible to DoD... DD Form 2585, ``Repatriation Processing Center Processing Sheet'', has numerous functions, but is...

5. VIEW OF BERYLLIUM PROCESSING AREA, ROLLING MILL. BERYLLIUM FORMING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF BERYLLIUM PROCESSING AREA, ROLLING MILL. BERYLLIUM FORMING BEGAN IN SIDE A OF THE BUILDING IN 1962. (11/5/73) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

Laser process and corresponding structures for fabrication of solar cells with shunt prevention dielectric

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harley, Gabriel; Smith, David D.; Dennis, Tim

Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

Processing and mechanical properties of metal-ceramic composites with controlled microstructure formed by reactive metal penetration

NASA Astrophysics Data System (ADS)

Ellerby, Donald Thomas

1999-12-01

Compared to monolithic ceramics, metal-reinforced ceramic composites offer the potential for improved toughness and reliability in ceramic materials. As such, there is significant scientific and commercial interest in the microstructure and properties of metal-ceramic composites. Considerable work has been conducted on modeling the toughening behavior of metal reinforcements in ceramics; however, there has been limited application and testing of these concepts on real systems. Composites formed by newly developed reactive processes now offer the flexibility to systematically control metal-ceramic composite microstructure, and to test some of the property models that have been proposed for these materials. In this work, the effects of metal-ceramic composite microstructure on resistance curve (R-curve) behavior, strength, and reliability were systematically investigated. Al/Al2O3 composites were formed by reactive metal penetration (RMP) of aluminum metal into aluminosilicate ceramic preforms. Processing techniques were developed to control the metal content, metal composition, and metal ligament size in the resultant composite microstructure. Quantitative stereology and microscopy were used to characterize the composite microstructures, and then the influence of microstructure on strength, toughness, R-curve behavior, and reliability, was investigated. To identify the strength limiting flaws in the composite microstructure, fractography was used to determine the failure origins. Additionally, the crack bridging tractions produced by the metal ligaments in metal-ceramic composites formed by the RMP process were modeled. Due to relatively large flaws and low bridging stresses in RMP composites, no dependence of reliability on R-curve behavior was observed. The inherent flaws formed during reactive processing appear to limit the strength and reliability of composites formed by the RMP process. This investigation has established a clear relationship between processing, microstructure, and properties in metal-ceramic composites formed by the RMP process. RMP composite properties are determined by the metal-ceramic composite microstructure (e.g., metal content and ligament size), which can be systematically varied by processing. Furthermore, relative to the ceramic preforms used to make the composites, metal-ceramic composites formed by RMP generally have improved properties and combinations of properties that make them more desirable for advanced engineering applications.

Dissociations between Imagery and Language Processing.

DTIC Science & Technology

1984-08-20

to form the image on the basis of information stored in memory . We wanted to eliminate such processing in order to assess image maintenance ability...of imagery described in Kosslyn (1980), three processing modules are used in generating an image from information stored in long-term memory . The...PICTURE processing module simply activates the stored information, forming an image in short-term memory . However, this processing module only activates

Multilayer ultra thick resist development for MEMS

NASA Astrophysics Data System (ADS)

Washio, Yasushi; Senzaki, Takahiro; Masuda, Yasuo; Saito, Koji; Obiya, Hiroyuki

2005-05-01

MEMS (Micro-Electro-Mechanical Systems) is achieved through a process technology, called Micro-machining. There are two distinct methods to manufacture a MEMS-product. One method is to form permanent film through photolithography, and the other is to form a non-permanent film resist after photolithography proceeded by etch or plating process. The three-dimensional ultra-fine processing technology based on photolithography, and is assembled by processes, such as anode junction, and post lithography processes such as etching and plating. Currently ORDYL PR-100 (Dry Film Type) is used for the permanent resist process. TOK has developed TMMR S2000 (Liquid Type) and TMMF S2000 (Dry Film Type) also. TOK has developed a new process utilizing these resist. The electro-forming method by photolithography is developed as one of the methods for enabling high resolution and high aspect formation. In recent years, it has become possible to manufacture conventionally difficult multilayer through our development with material and equipment project (M&E). As for material for electro-forming, it was checked that chemically amplified resist is optimal from the reaction mechanism as it is easily removed by the clean solution. Moreover, multiple plating formations were enabled with the resist through a new process. As for the equipment, TOK developed Applicator (It can apply 500 or more μms) and Developer, which achieves high throughput and quality. The detailed plating formations, which a path differs, and air wiring are realizable through M&E. From the above results, opposed to metallic mold plating, electro-forming method by resist, enabled to form high resolution and aspect pattern, at low cost. It is thought that the infinite possibility spreads by applying this process.

Electrical-assisted double side incremental forming and processes thereof

DOEpatents

Roth, John; Cao, Jian

2014-06-03

A process for forming a sheet metal component using an electric current passing through the component is provided. The process can include providing a double side incremental forming machine, the machine operable to perform a plurality of double side incremental deformations on the sheet metal component and also apply an electric direct current to the sheet metal component during at least part of the forming. The direct current can be applied before or after the forming has started and/or be terminated before or after the forming has stopped. The direct current can be applied to any portion of the sheet metal. The electrical assistance can reduce the magnitude of force required to produce a given amount of deformation, increase the amount of deformation exhibited before failure and/or reduce any springback typically exhibited by the sheet metal component.

I-NERI-2007-004-K, DEVELOPMENT AND CHARACTERIZATION OF NEW HIGH-LEVEL WASTE FORMS FOR ACHIEVING WASTE MINIMIZATION FROM PYROPROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.M. Frank

Work describe in this report represents the final year activities for the 3-year International Nuclear Energy Research Initiative (I-NERI) project: Development and Characterization of New High-Level Waste Forms for Achieving Waste Minimization from Pyroprocessing. Used electrorefiner salt that contained actinide chlorides and was highly loaded with surrogate fission products was processed into three candidate waste forms. The first waste form, a high-loaded ceramic waste form is a variant to the CWF produced during the treatment of Experimental Breeder Reactor-II used fuel at the Idaho National Laboratory (INL). The two other waste forms were developed by researchers at the Korean Atomicmore » Energy Research Institute (KAERI). These materials are based on a silica-alumina-phosphate matrix and a zinc/titanium oxide matrix. The proposed waste forms, and the processes to fabricate them, were designed to immobilize spent electrorefiner chloride salts containing alkali, alkaline earth, lanthanide, and halide fission products that accumulate in the salt during the processing of used nuclear fuel. This aspect of the I-NERI project was to demonstrate 'hot cell' fabrication and characterization of the proposed waste forms. The outline of the report includes the processing of the spent electrorefiner salt and the fabrication of each of the three waste forms. Also described is the characterization of the waste forms, and chemical durability testing of the material. While waste form fabrication and sample preparation for characterization must be accomplished in a radiological hot cell facility due to hazardous radioactivity levels, smaller quantities of each waste form were removed from the hot cell to perform various analyses. Characterization included density measurement, elemental analysis, x-ray diffraction, scanning electron microscopy and the Product Consistency Test, which is a leaching method to measure chemical durability. Favorable results from this demonstration project will provide additional options for fission product immobilization and waste management associated the electrochemical/pyrometallurgical processing of used nuclear fuel.« less

Effects of attention and laterality on motion and orientation discrimination in deaf signers.

PubMed

Bosworth, Rain G; Petrich, Jennifer A F; Dobkins, Karen R

2013-06-01

Previous studies have asked whether visual sensitivity and attentional processing in deaf signers are enhanced or altered as a result of their different sensory experiences during development, i.e., auditory deprivation and exposure to a visual language. In particular, deaf and hearing signers have been shown to exhibit a right visual field/left hemisphere advantage for motion processing, while hearing nonsigners do not. To examine whether this finding extends to other aspects of visual processing, we compared deaf signers and hearing nonsigners on motion, form, and brightness discrimination tasks. Secondly, to examine whether hemispheric lateralities are affected by attention, we employed a dual-task paradigm to measure form and motion thresholds under "full" vs. "poor" attention conditions. Deaf signers, but not hearing nonsigners, exhibited a right visual field advantage for motion processing. This effect was also seen for form processing and not for the brightness task. Moreover, no group differences were observed in attentional effects, and the motion and form visual field asymmetries were not modulated by attention, suggesting they occur at early levels of sensory processing. In sum, the results show that processing of motion and form, believed to be mediated by dorsal and ventral visual pathways, respectively, are left-hemisphere dominant in deaf signers. Published by Elsevier Inc.

Development of a novel cold forging process to manufacture eccentric shafts

NASA Astrophysics Data System (ADS)

Pasler, Lukas; Liewald, Mathias

2018-05-01

Since the commercial usage of compact combustion engines, eccentric shafts have been used to transform translational into rotational motion. Over the years, several processes to manufacture these eccentric shafts or crankshafts have been developed. Especially for single-cylinder engines manufactured in small quantities, built crankshafts disclose advantages regarding tooling costs and performance. Those manufacturing processes do have one thing in common: They are all executed at elevated temperatures to enable the material to be formed to high forming degree. In this paper, a newly developed cold forging process is presented, which combines lateral extrusion and shifting for manufacturing a crank in one forming operation at room temperature. In comparison to the established upsetting and shifting methods to manufacture such components, the tool cavity or crank web thickness remains constant. Therefore, the developed new process presented in this paper consists of a combination of shifting and extrusion of the billet, which allows pushing material into the forming zone during shifting. In order to reduce the tensile stresses induced by the shifting process, compressive stresses are superimposed. It is expected that the process limits will be expanded regarding the horizontal displacement and form filling. In the following report, the simulation and design of the tooling concept are presented. Experiments were conducted and compared with corresponding simulation results afterwards.

Preformulation considerations for controlled release dosage forms. Part I. Selecting candidates.

PubMed

Chrzanowski, Frank

2008-01-01

The physical-chemical properties of interest for controlled release (CR) dosage form development presented are based on the author's experience. Part I addresses selection of the final form based on a logical progression of physical-chemical properties evaluation of candidate forms and elimination of forms with undesirable properties from further evaluation in order to simplify final form selection. Several candidate forms which could include salt, free base or acid, polymorphic and amorphic forms of a new chemical entity (NCE) or existing drug substance (DS) are prepared and evaluated for critical properties in a scheme relevant to manufacturing processes, predictive of problems, requiring small amounts of test materials and simple analytical tools. A stability indicating assay is not needed to initiate the evaluation. This process is applicable to CR and immediate release (IR) dosage form development. The critical properties evaluated are melting, crystallinity, solubilities in water, 0.1 N HCl, and SIF, hygrodymamics, i.e., moisture sorption and loss at extremes of RH, and LOD at typical wet granulation drying conditions, and processability, i.e., corrosivity, and filming and/or sticking upon compression.

Method for Fabricating Composite Structures Using Pultrusion Processing

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

2000-01-01

A method for fabricating composite structures at a low-cost, moderate-to-high production rate. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform and debulking the partially debulked preform to form a net-shape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length and electron-beam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates, resulting in lower cost and high structural performance.

Method for Fabricating Composite Structures Using Pultrusion Processing

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

2000-01-01

A method for fabricating composite structures at a low-cost, moderate-to-high production rate. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform and debulking the partially debulked preform to form a netshape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length and electronbeam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates, resulting in lower cost and high structural performance.

17 CFR 269.5 - Form F-X, for appointment of agent for service of process by issuers registering securities on...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Form F-X, for appointment of... INDENTURE ACT OF 1939 § 269.5 Form F-X, for appointment of agent for service of process by issuers..., F-10 or F-80. Form F-X shall be filed with the Commission: (a) By any issuer registering securities...

17 CFR 269.5 - Form F-X, for appointment of agent for service of process by issuers registering securities on...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Form F-X, for appointment of... INDENTURE ACT OF 1939 § 269.5 Form F-X, for appointment of agent for service of process by issuers..., F-10 or F-80. Form F-X shall be filed with the Commission: (a) By any issuer registering securities...

High Pressure Pneumatic Forming of Ti-3Al-2.5V Titanium Tubes in a Square Cross-Sectional Die

PubMed Central

Liu, Gang; Wang, Jianlong; Dang, Kexin; Tang, Zejun

2014-01-01

A new high strain rate forming process for titanium alloys is presented and named High Pressure Pneumatic Forming (HPPF), which might be applicable to form certain tubular components with irregular cross sections with high efficiency, both with respect to energy cost and time consumption. HPPF experiments were performed on Ti-3Al-2.5V titanium alloy tubes using a square cross-sectional die with a small corner radius. The effects of forming of pressure and temperature on the corner filling were investigated and the thickness distributions after the HPPF processes at various pressure levels are discussed. At the same time, the stress state, strain and strain rate distribution during the HPPF process were numerically analyzed by the finite element method. Microstructure evolution of the formed tubes was also analyzed by using electron back scattering diffraction (EBSD). Because of different stress states, the strain and strain rate are very different at different areas of the tube during the corner filling process, and consequently the microstructure of the formed component is affected to some degree. The results verified that HPPF is a potential technology to form titanium tubular components with complicated geometrical features with high efficiency. PMID:28788173

A modular tooling set-up for incremental sheet forming (ISF) with subsequent stress-relief annealing under partial constraints

NASA Astrophysics Data System (ADS)

Maqbool, Fawad; Bambach, Markus

2017-10-01

Incremental sheet forming (ISF) is a manufacturing process most suitable for small-batch production of sheet metal parts. In ISF, a CNC-controlled tool moves over the sheet metal, following a specified contour to form a part of the desired geometry. This study focuses on one of the dominant process limitations associated with the ISF, i.e., the limited geometrical accuracy. In this regard, a case study is performed which shows that increased geometrical accuracy of the formed part can be achieved by a using stress-relief annealing before unclamping. To keep the tooling costs low, a modular die design consisting of a stiff metal frame and inserts made from inexpensive plastics (Sika®) were devised. After forming, the plastics inserts are removed. The metal frame supports the part during stress-relief annealing. Finite Element (FE) simulations of the manufacturing process are performed. Due to the residual stresses induced during the forming, the geometry of the formed part, from FE simulation and the actual manufacturing process, shows severe distortion upon unclamping the part. Stress relief annealing of the formed part under partial constraints exerted by the tool frame shows that a part with high geometrical accuracy can be obtained.

Modeling Production Plant Forming Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rhee, M; Becker, R; Couch, R

2004-09-22

Engineering has simulation tools and experience in modeling forming processes. Y-12 personnel have expressed interest in validating our tools and experience against their manufacturing process activities such as rolling, casting, and forging etc. We have demonstrated numerical capabilities in a collaborative DOE/OIT project with ALCOA that is nearing successful completion. The goal was to use ALE3D to model Alcoa's slab rolling process in order to demonstrate a computational tool that would allow Alcoa to define a rolling schedule that would minimize the probability of ingot fracture, thus reducing waste and energy consumption. It is intended to lead to long-term collaborationmore » with Y-12 and perhaps involvement with other components of the weapons production complex. Using simulations to aid in design of forming processes can: decrease time to production; reduce forming trials and associated expenses; and guide development of products with greater uniformity and less scrap.« less

Study on loading path optimization of internal high pressure forming process

NASA Astrophysics Data System (ADS)

Jiang, Shufeng; Zhu, Hengda; Gao, Fusheng

2017-09-01

In the process of internal high pressure forming, there is no formula to describe the process parameters and forming results. The article use numerical simulation to obtain several input parameters and corresponding output result, use the BP neural network to found their mapping relationship, and with weighted summing method make each evaluating parameters to set up a formula which can evaluate quality. Then put the training BP neural network into the particle swarm optimization, and take the evaluating formula of the quality as adapting formula of particle swarm optimization, finally do the optimization and research at the range of each parameters. The results show that the parameters obtained by the BP neural network algorithm and the particle swarm optimization algorithm can meet the practical requirements. The method can solve the optimization of the process parameters in the internal high pressure forming process.

Role of mitochondrial processing peptidase and AAA proteases in processing of the yeast acetohydroxyacid synthase precursor.

PubMed

Dasari, Suvarna; Kölling, Ralf

2016-07-01

We studied presequence processing of the mitochondrial-matrix targeted acetohydroxyacid synthase (Ilv2). C-terminal 3HA-tagging altered the cleavage pattern from a single step to sequential two-step cleavage, giving rise to two Ilv2-3HA forms (A and B). Both cleavage events were dependent on the mitochondrial processing peptidase (MPP). We present evidence for the involvement of three AAA ATPases, m- and i-AAA proteases, and Mcx1, in Ilv2-3HA processing. Both, precursor to A-form and A-form to B-form cleavage were strongly affected in a ∆yme1 mutant. These defects could be suppressed by overexpression of MPP, suggesting that MPP activity is limiting in the ∆yme1 mutant. Our data suggest that for some substrates AAA ATPases could play an active role in the translocation of matrix-targeted proteins.

Process for forming shaped group III-V semiconductor nanocrystals, and product formed using process

DOEpatents

Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

2001-01-01

A process for the formation of shaped Group III-V semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

Process for forming shaped group II-VI semiconductor nanocrystals, and product formed using process

DOEpatents

Alivisatos, A. Paul; Peng, Xiaogang; Manna, Liberato

2001-01-01

A process for the formation of shaped Group II-VI semiconductor nanocrystals comprises contacting the semiconductor nanocrystal precursors with a liquid media comprising a binary mixture of phosphorus-containing organic surfactants capable of promoting the growth of either spherical semiconductor nanocrystals or rod-like semiconductor nanocrystals, whereby the shape of the semiconductor nanocrystals formed in said binary mixture of surfactants is controlled by adjusting the ratio of the surfactants in the binary mixture.

Vitality Forms Processing in the Insula during Action Observation: A Multivoxel Pattern Analysis

PubMed Central

Di Cesare, Giuseppe; Valente, Giancarlo; Di Dio, Cinzia; Ruffaldi, Emanuele; Bergamasco, Massimo; Goebel, Rainer; Rizzolatti, Giacomo

2016-01-01

Observing the style of an action done by others allows the observer to understand the cognitive state of the agent. This information has been defined by Stern “vitality forms”. Previous experiments showed that the dorso-central insula is selectively active both during vitality form observation and execution. In the present study, we presented participants with videos showing hand actions performed with different velocities and asked them to judge either their vitality form (gentle, neutral, rude) or their velocity (slow, medium, fast). The aim of the present study was to assess, using multi-voxel pattern analysis, whether vitality forms and velocities of observed goal-directed actions are differentially processed in the insula, and more specifically whether action velocity is encoded per se or it is an element that triggers neural populations of the insula encoding the vitality form. The results showed that, consistently across subjects, in the dorso-central sector of the insula there were voxels selectively tuned to vitality forms, while voxel tuned to velocity were rare. These results indicate that the dorso-central insula, which previous data showed to be involved in the vitality form processing, contains voxels specific for the action style processing. PMID:27375461

Improving Reliability of a Residency Interview Process

PubMed Central

Serres, Michelle L.; Gundrum, Todd E.

2013-01-01

Objective. To improve the reliability and discrimination of a pharmacy resident interview evaluation form, and thereby improve the reliability of the interview process. Methods. In phase 1 of the study, authors used a Many-Facet Rasch Measurement model to optimize an existing evaluation form for reliability and discrimination. In phase 2, interviewer pairs used the modified evaluation form within 4 separate interview stations. In phase 3, 8 interviewers individually-evaluated each candidate in one-on-one interviews. Results. In phase 1, the evaluation form had a reliability of 0.98 with person separation of 6.56; reproducibly, the form separated applicants into 6 distinct groups. Using that form in phase 2 and 3, our largest variation source was candidates, while content specificity was the next largest variation source. The phase 2 g-coefficient was 0.787, while confirmatory phase 3 was 0.922. Process reliability improved with more stations despite fewer interviewers per station—impact of content specificity was greatly reduced with more interview stations. Conclusion. A more reliable, discriminating evaluation form was developed to evaluate candidates during resident interviews, and a process was designed that reduced the impact from content specificity. PMID:24159209

Processing of mammalian preprogastrin-releasing peptide.

PubMed

Reeve, J R; Cuttitta, F; Vigna, S R; Shively, J E; Walsh, J H

1988-01-01

The processing of preprogastrin-releasing peptide in mammalian tissues and in cultured cells takes place at discrete sites (Figure 6). Signal peptidase cleaves away the signal peptide from the amino terminus of gastrin-releasing peptide. An exopeptidase activity may remove dipeptides from the amino terminus. The amidation site (not shown in Fig. 6; see Fig. 2) has the same general sequence (Gly-Lys-Lys) seen for other amidated peptides. Cleavage after single basic residues yields gene-related products from Form I or II preproGRP. A unique non-basic cleavage yields a gene-related product from Form III preproGRP. The processing that occurs to form GRP, GRP, and GRP gene-related peptides is shown in Figure 7. ProGRP is cleaved by a series of enzymes to form GRP with an amidated carboxyl-terminal methionine (indicated by an asterisk in Fig. 7). GRP is cleaved to form the decapeptide GRP. The carboxyl-terminal flanking peptides of all three mRNA translation products are cleaved to form several gastrin-releasing peptide gene-related products. Knowledge of the processing of gastrin-releasing peptide and its gene-related products will allow synthesis of duplicates of the stored forms of these peptides, which can then be used for biological testing.

Rapid Freeform Sheet Metal Forming: Technology Development and System Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiridena, Vijitha; Verma, Ravi; Gutowski, Timothy

The objective of this project is to develop a transformational RApid Freeform sheet metal Forming Technology (RAFFT) in an industrial environment, which has the potential to increase manufacturing energy efficiency up to ten times, at a fraction of the cost of conventional technologies. The RAFFT technology is a flexible and energy-efficient process that eliminates the need for having geometry-specific forming dies. The innovation lies in the idea of using the energy resource at the local deformation area which provides greater formability, process control, and process flexibility relative to traditional methods. Double-Sided Incremental Forming (DSIF), the core technology in RAFFT, ismore » a new concept for sheet metal forming. A blank sheet is clamped around its periphery and gradually deformed into a complex 3D freeform part by two strategically aligned stylus-type tools that follow a pre-described toolpath. The two tools, one on each side of the blank, can form a part with sharp features for both concave and convex shapes. Since deformation happens locally, the forming force at any instant is significantly decreased when compared to traditional methods. The key advantages of DSIF are its high process flexibility, high energy-efficiency, low capital investment, and the elimination of the need for massive amounts of die casting and machining. Additionally, the enhanced formability and process flexibility of DSIF can open up design spaces and result in greater weight savings.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eun, H.C.; Cho, Y.Z.; Choi, J.H.

A regeneration process of LiCl-KCl eutectic waste salt generated from the pyrochemical process of spent nuclear fuel has been studied. This regeneration process is composed of a chemical conversion process and a vacuum distillation process. Through the regeneration process, a high efficiency of renewable salt recovery can be obtained from the waste salt and rare earth nuclides in the waste salt can be separated as oxide or phosphate forms. Thus, the regeneration process can contribute greatly to a reduction of the waste volume and a creation of durable final waste forms. (authors)

A study on using pre-forming blank in single point incremental forming process by finite element analysis

NASA Astrophysics Data System (ADS)

Abass, K. I.

2016-11-01

Single Point Incremental Forming process (SPIF) is a forming technique of sheet material based on layered manufacturing principles. The edges of sheet material are clamped while the forming tool is moved along the tool path. The CNC milling machine is used to manufacturing the product. SPIF involves extensive plastic deformation and the description of the process is more complicated by highly nonlinear boundary conditions, namely contact and frictional effects have been accomplished. However, due to the complex nature of these models, numerical approaches dominated by Finite Element Analysis (FEA) are now in widespread use. The paper presents the data and main results of a study on effect of using preforming blank in SPIF through FEA. The considered SPIF has been studied under certain process conditions referring to the test work piece, tool, etc., applying ANSYS 11. The results show that the simulation model can predict an ideal profile of processing track, the behaviour of contact tool-workpiece, the product accuracy by evaluation its thickness, surface strain and the stress distribution along the deformed blank section during the deformation stages.

Novel process chain for hot metal gas forming of ferritic stainless steel 1.4509

NASA Astrophysics Data System (ADS)

Mosel, André; Lambarri, Jon; Degenkolb, Lars; Reuther, Franz; Hinojo, José Luis; Rößiger, Jörg; Eurich, Egbert; Albert, André; Landgrebe, Dirk; Wenzel, Holger

2018-05-01

Exhaust gas components of automobiles are often produced in ferritic stainless steel 1.4509 due to the low thermal expansion coefficient and the low material price. Until now, components of the stainless steel with complex geometries have been produced in series by means of multi-stage hydroforming at room temperature with intermediate annealing operations. The application of a single-stage hot-forming process, also referred to as hot metal gas forming (HMGF), offers great potential to significantly reduce the production costs of such components. The article describes a novel process chain for the HMGF process. Therefore the tube is heated in two steps. After pre-heating of the semi-finished product outside the press, the tube is heated up to forming start temperature by means of a tool-integrated conductive heating before forming. For the tube of a demonstrator geometry, a simulation model for the conduction heating was set up. In addition to the tool development for this process, experimental results are also described for the production of the demonstrator geometry.

A novel proteolytic processing of prolysyl oxidase.

PubMed

Atsawasuwan, Phimon; Mochida, Yoshiyuki; Katafuchi, Michitsuna; Tokutomi, Kentaro; Mocanu, Viorel; Parker, Carol E; Yamauchi, Mitsuo

2011-01-01

Lysyl oxidase (LOX) is an amine oxidase that is critical for the stability of connective tissues. The secreted proLOX is enzymatically quiescent and is activated through proteolytic cleavage between residues Gly(162) and Asp(163) (residue numbers according to the mouse LOX) by bone morphogenetic protein (BMP)-1 gene products. Here we report a novel processing of proLOX identified in vitro and in vivo. Two forms of mature LOX were identified and characterized by their immunoreactivity to specific antibodies, amine oxidase activity, and mass spectrometry. One form was identified as a well-characterized BMP-1 processed LOX protein. Another was found to be a truncated form of LOX resulting from the cleavage at the carboxy terminus of Arg(192). The truncated form of LOX still appeared to retain amine oxidase activity. The results from the proLOX gene deletion and mutation experiments indicated that the processing occurs independent of the cleavage of proLOX by BMP-1 gene products and likely requires the presence of LOX propeptide. These results indicate that proLOX could be processed by two different mechanisms producing two forms of active LOX.

Mechanical and Metallurgical Evolution of Stainless Steel 321 in a Multi-step Forming Process

NASA Astrophysics Data System (ADS)

Anderson, M.; Bridier, F.; Gholipour, J.; Jahazi, M.; Wanjara, P.; Bocher, P.; Savoie, J.

2016-04-01

This paper examines the metallurgical evolution of AISI Stainless Steel 321 (SS 321) during multi-step forming, a process that involves cycles of deformation with intermediate heat treatment steps. The multi-step forming process was simulated by implementing interrupted uniaxial tensile testing experiments. Evolution of the mechanical properties as well as the microstructural features, such as twins and textures of the austenite and martensite phases, was studied as a function of the multi-step forming process. The characteristics of the Strain-Induced Martensite (SIM) were also documented for each deformation step and intermediate stress relief heat treatment. The results indicated that the intermediate heat treatments considerably increased the formability of SS 321. Texture analysis showed that the effect of the intermediate heat treatment on the austenite was minor and led to partial recrystallization, while deformation was observed to reinforce the crystallographic texture of austenite. For the SIM, an Olson-Cohen equation type was identified to analytically predict its formation during the multi-step forming process. The generated SIM was textured and weakened with increasing deformation.

Wireless SAW Sensors Having Integrated Antennas

NASA Technical Reports Server (NTRS)

Malocha, Donald C. (Inventor); Gallagher, Mark (Inventor)

2015-01-01

A wireless surface acoustic wave sensor includes a piezoelectric substrate, a surface acoustic wave device formed on the substrate, and an antenna formed on the substrate. In some embodiments, the antenna is formed on the surface of the substrate using one or more of photolithography, thin film processing, thick film processing, plating, and printing.

A Japanese Child's Use of Stative and Punctual Verbs.

ERIC Educational Resources Information Center

Cziko, Gary A.; Koda, Keiko

1987-01-01

Investigation of use of stative, process, punctual, and non-punctual verbs by a child acquiring Japanese as a first language found that sampled present progressive verb forms occurred with process verbs while these forms were never used with stative verbs. Most omissions of present progressive forms occurred with the early use of "mixed"…

Possibilities of Particle Finite Element Methods in Industrial Forming Processes

NASA Astrophysics Data System (ADS)

Oliver, J.; Cante, J. C.; Weyler, R.; Hernandez, J.

2007-04-01

The work investigates the possibilities offered by the particle finite element method (PFEM) in the simulation of forming problems involving large deformations, multiple contacts, and new boundaries generation. The description of the most distinguishing aspects of the PFEM, and its application to simulation of representative forming processes, illustrate the proposed methodology.

Low temperature junction growth using hot-wire chemical vapor deposition

DOEpatents

Wang, Qi; Page, Matthew; Iwaniczko, Eugene; Wang, Tihu; Yan, Yanfa

2014-02-04

A system and a process for forming a semi-conductor device, and solar cells (10) formed thereby. The process includes preparing a substrate (12) for deposition of a junction layer (14); forming the junction layer (14) on the substrate (12) using hot wire chemical vapor deposition; and, finishing the semi-conductor device.

Continuous, linearly intermixed fiber tows and composite molded article thereform

NASA Technical Reports Server (NTRS)

McMahon, Paul E. (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

2000-01-01

The instant invention involves a process used in preparing fibrous tows which may be formed into polymeric plastic composites. The process involves the steps of (a) forming a carbon fiber tow; (b) forming a thermoplastic polymeric fiber tow; (c) intermixing the two tows; and (d) withdrawing the intermixed tow for further use.

An Evaluation of the Factor Structure of the HRM Survey, Forms 9 and 11

DTIC Science & Technology

1976-07-01

Equal Opportunity Index, Social Problems and Processes Equal ...5 2 Equal 64-67 (Form 9) Opportunity 65-68,70 (Form 11) Equal Opportunity, Social Problems and Processes Equal Opportunity, Social ... Social Problems Equal Opportunity Index, Social Problems Drug Abuse Index, Social Problems Alcholism Prevention Index, Social Problems

Investigating the principles of recrystallization from glyceride melts.

PubMed

Windbergs, Maike; Strachan, Clare J; Kleinebudde, Peter

2009-01-01

Different lipids were melted and resolidified as model systems to gain deeper insight into the principles of recrystallization processes in lipid-based dosage forms. Solid-state characterization was performed on the samples with differential scanning calorimetry and X-ray powder diffraction. Several recrystallization processes could be identified during storage of the lipid layers. Pure triglycerides that generally crystallize to the metastable alpha-form from the melt followed by a recrystallization process to the stable beta-form with time showed a chain-length-dependent behavior during storage. With increasing chain length, the recrystallization to the stable beta-form was decelerated. Partial glycerides exhibited a more complex recrystallization behavior due to the fact that these substances are less homogenous. Mixtures of a long-chain triglyceride and a partial glyceride showed evidence of some interaction between the two components as the partial glyceride hindered the recrystallization of the triglyceride to the stable beta-form. In addition, the extent of this phenomenon depended on the amount of partial glyceride in the mixture. Based on these results, changes in solid dosage forms based on glycerides during processing and storage can be better understood.

On the general constraints in single qubit quantum process tomography

DOE PAGES

Bhandari, Ramesh; Peters, Nicholas A.

2016-05-18

In this study, we briefly review single-qubit quantum process tomography for trace-preserving and nontrace-preserving processes, and derive explicit forms of the general constraints for fitting experimental data. These forms provide additional insight into the structure of the process matrix. We illustrate this with several examples, including a discussion of qubit leakage error models and the intuition which can be gained from their process matrices.

Impact of the rate of the additive process of forming a heavy structure deforming in creep on the development of its technological stresses

NASA Astrophysics Data System (ADS)

Parshin, Dmitry A.

2018-05-01

The additive process of forming a semicircular arched structure by means of layer-by-layer addition of material to its inner surface is simulated. The impact of this process running mode on the development of the technological stresses fields in the structure being formed under the action of gravity under properties of the material creep and aging is examined. In the framework of the linear mechanics of accreted solids a mathematical model of the process under study is offered and numerical experiments are conducted. It is shown that the stress-strain state of the additively formed heavy objects decisively depends on their formation mode. Various practically important trends and features of this dependence are studied.

Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process

DOEpatents

Balachandran, Uthamalingam

1996-01-01

A process for the preparation of amorphous precursor powders for Pb-doped Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (2223) includes a freeze-drying process incorporating a splat-freezing step. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution without any phase separation; grinding the frozen flakes to form a powder; freeze-drying the frozen powder; heating the dried powder to form a dry green precursor powders; denitrating the green-powders; heating the denitrated powders to form phase-clean Bi-2223 powders. The grain boundaries of the 2223 grains appear to be clean, leading to good intergrain contact between 2223 grains.

Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process

DOEpatents

Balachandran, U.

1996-06-04

A process for the preparation of amorphous precursor powders for Pb-doped Bi{sub 2}Sr{sub 2} Ca{sub 2}Cu{sub 3}O{sub x} (2223) includes a freeze-drying process incorporating a splat-freezing step. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution without any phase separation; grinding the frozen flakes to form a powder; freeze-drying the frozen powder; heating the dried powder to form a dry green precursor powders; denitrating the green-powders; heating the denitrated powders to form phase-clean Bi-2223 powders. The grain boundaries of the 2223 grains appear to be clean, leading to good intergrain contact between 2223 grains. 11 figs.

Cloning, preparation and preliminary crystallographic studies of penicillin V acylase autoproteolytic processing mutants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandra, P. Manish; Brannigan, James A., E-mail: jab@ysbl.york.ac.uk; Prabhune, Asmita

The production, crystallization and characterization of three inactive mutants of penicillin V acylase from B. sphaericus in their respective precursor and processed forms are reported. The space groups are different for the native enzyme and the mutants. The crystallization of three catalytically inactive mutants of penicillin V acylase (PVA) from Bacillus sphaericus in precursor and processed forms is reported. The mutant proteins crystallize in different primitive monoclinic space groups that are distinct from the crystal forms for the native enzyme. Directed mutants and clone constructs were designed to study the post-translational autoproteolytic processing of PVA. The catalytically inactive mutants willmore » provide three-dimensional structures of precursor PVA forms, plus open a route to the study of enzyme–substrate complexes for this industrially important enzyme.« less

40 CFR 463.21 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AND STANDARDS (CONTINUED) PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY Cleaning Water... “average process water usage flow rate” for a plant with more than one plastics molding and forming process... a cleaning process and comes in contact with the plastic product over a period of one year. ...

40 CFR 463.31 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AND STANDARDS (CONTINUED) PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY Finishing Water... “average process water usage flow rate” for a plant with more than one plastics molding and forming process... a finishing water process and comes in contact with the plastics product over a period of one year. ...

40 CFR 463.21 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AND STANDARDS (CONTINUED) PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY Cleaning Water... “average process water usage flow rate” for a plant with more than one plastics molding and forming process... a cleaning process and comes in contact with the plastic product over a period of one year. ...

40 CFR 463.31 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AND STANDARDS (CONTINUED) PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY Finishing Water... “average process water usage flow rate” for a plant with more than one plastics molding and forming process... a finishing water process and comes in contact with the plastics product over a period of one year. ...

Simulation and Analysis of One-time Forming Process of Automobile Steering Ball Head

NASA Astrophysics Data System (ADS)

Shi, Peicheng; Zhang, Xujun; Xu, Zengwei; Zhang, Rongyun

2018-03-01

Aiming at the problems such as large machining allowance, low production efficiency and material waste during die forging of ball pin, the cold extrusion process of ball head was studied and the analog simulation of the forming process was carried out by using the finite element analysis software DEFORM-3D. Through the analysis of the equivalent stress strain, velocity vector field and load-displacement curve, the flow regularity of the metal during the cold extrusion process of ball pin was clarified, and possible defects during the molding were predicted. The results showed that this process could solve the forming problem of ball pin and provide theoretical basis for actual production of enterprises.

Electrochemical formation of field emitters

DOEpatents

Bernhardt, Anthony F.

1999-01-01

Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

Process for manufacturing tantalum capacitors

DOEpatents

Lauf, Robert J.; Holcombe, Cressie E.; Dykes, Norman L.

1993-01-01

A process for manufacturing tantalum capacitors in which microwave energy is used to sinter a tantalum powder compact in order to achieve higher surface area and improved dielectric strength. The process comprises cold pressing tantalum powder with organic binders and lubricants to form a porous compact. After removal of the organics, the tantalum compact is heated to 1300.degree. to 2000.degree. C. by applying microwave radiation. Said compact is then anodized to form a dielectric oxide layer and infiltrated with a conductive material such as MnO.sub.2. Wire leads are then attached to form a capacitor to said capacitor is hermetically packaged to form the finished product.

Process for manufacturing tantalum capacitors

DOEpatents

Lauf, R.J.; Holcombe, C.E.; Dykes, N.L.

1993-02-02

A process for manufacturing tantalum capacitors in which microwave energy is used to sinter a tantalum powder compact in order to achieve higher surface area and improved dielectric strength. The process comprises cold pressing tantalum powder with organic binders and lubricants to form a porous compact. After removal of the organics, the tantalum compact is heated to 1,300 to 2,000 C by applying microwave radiation. Said compact is then anodized to form a dielectric oxide layer and infiltrated with a conductive material such as MnO[sub 2]. Wire leads are then attached to form a capacitor to said capacitor is hermetically packaged to form the finished product.

Process Mechanics Analysis in Single Point Incremental Forming

NASA Astrophysics Data System (ADS)

Ambrogio, G.; Filice, L.; Fratini, L.; Micari, F.

2004-06-01

The request of highly differentiated products and the need of process flexibility have brought the researchers to focus the attention on innovative sheet forming processes. Industrial application of conventional processes is, in fact, economically convenient just for large scale productions; furthermore conventional processes do not allow to fully satisfy the mentioned demand of flexibility. In this contest, single point incremental forming (SPIF) is an innovative and flexible answer to market requests. The process is characterized by a peculiar process mechanics, being the sheet plastically deformed only through a localised stretching mechanism. Some recent experimental studies have shown that SPIF permits a relevant increase of formability limits, just as a consequence of the peculiar deformation mechanics. The research here addressed is focused on the theoretical investigation of process mechanics; the aim was to achieve a deeper understanding of basic phenomena involved in SPIF which justify the above mentioned formability enhancing.

Coated substrates and process

DOEpatents

Chu, Wei-kan; Childs, Charles B.

1991-01-01

Disclosed herein is a coated substrate and a process for forming films on substrates and for providing a particularly smooth film on a substrate. The method of this invention involves subjecting a surface of a substrate to contact with a stream of ions of an inert gas having sufficient force and energy to substantially change the surface characteristics of said substrate, and then exposing a film-forming material to a stream of ions of an inert gas having sufficient energy to vaporize the atoms of said film-forming material and to transmit the vaporized atoms to the substrate surface with sufficient force to form a film bonded to the substrate. This process is particularly useful commercially because it forms strong bonds at room temperature. This invention is particularly useful for adhering a gold film to diamond and forming ohmic electrodes on diamond, but also can be used to bond other films to substrates.

The relationship between the content and the form of metaphorical statements.

PubMed

Xu, Xu

2010-04-01

Recent research suggests that the quality of a metaphorical topic-vehicle pairing should be the determinant to the choice of a proper grammatical form, nominal metaphor versus simile. Two studies examined the relationship between the quality of the content of a metaphorical statement and its grammatical form. Study 1 showed that the two grammatical forms did not differ in aptness when the quality of topic-vehicle pairs and the conventionality of vehicles, a factor associated with the quality of metaphorical expressions, were controlled. With an online comprehension measure, Study 2 found that high quality metaphorical pairings were easier to process than low quality metaphorical pairings in both the metaphor form and the simile form. For high quality metaphorical pairings, information related to both the topics and the vehicles was highly activated at an early stage of processing. The relations among factors involved in the interpretive process of metaphorical language are discussed.

On three forms of thinking: magical thinking, dream thinking, and transformative thinking.

PubMed

Ogden, Thomas H

2010-04-01

The author believes that contemporary psychoanalysis has shifted its emphasis from the understanding of the symbolic meaning of dreams, play, and associations to the exploration of the processes of thinking, dreaming, and playing. In this paper, he discusses his understanding of three forms of thinking-magical thinking, dream thinking, and transformative thinking-and provides clinical illustrations in which each of these forms of thinking figures prominently. The author views magical thinking as a form of thinking that subverts genuine thinking and psychological growth by substituting invented psychic reality for disturbing external reality. By contrast, dream thinking--our most profound form of thinking-involves viewing an emotional experience from multiple perspectives simultaneously: for example, the perspectives of primary process and secondary process thinking. In transformative thinking, one creates a new way of ordering experience that allows one to generate types of feeling, forms of object relatedness, and qualities of aliveness that had previously been unimaginable.

The explicit form of the rate function for semi-Markov processes and its contractions

NASA Astrophysics Data System (ADS)

Sughiyama, Yuki; Kobayashi, Testuya J.

2018-03-01

We derive the explicit form of the rate function for semi-Markov processes. Here, the ‘random time change trick’ plays an essential role. Also, by exploiting the contraction principle of large deviation theory to the explicit form, we show that the fluctuation theorem (Gallavotti-Cohen symmetry) holds for semi-Markov cases. Furthermore, we elucidate that our rate function is an extension of the level 2.5 rate function for Markov processes to semi-Markov cases.

Drainage morphometric analysis for assessing form and processes of the watersheds of Pachamalai hills and its adjoinings, Central Tamil Nadu, India

NASA Astrophysics Data System (ADS)

Prabhakaran, A.; Jawahar Raj, N.

2018-03-01

The present study attempts to understand the form and geomorphic/hydrologic processes of the 20 watersheds of the Pachamalai hills and its adjoinings located in Tamil Nadu State of southern India from the analysis of its drainage morphometric characteristics. Survey of India's topographic sheets of 1:50,000 is the data source from which stream networks and watersheds of the study area were demarcated followed by the analysis of their morphometric characteristics using ArcGIS software. The results of the analysis formed the basis for deducing the form and processes of the watersheds of the study area. The form of the watersheds inferred from the analysis includes shape, length, slope steepness and length, degree of branching of streams, dissection and elongation of watersheds. The geomorphic/hydrologic processes inferred include denudation rate, potential energy, intensity of erosion, mean annual run off, mean discharge, discharge rate, rock resistivity and infiltration potential, amount of sediment transported, mean annual rainfall, rainfall intensity, lagtime, flash flood potential, flood discharge per unit area, sediment yield and speed of the water flow in the streams. The understanding of variations of form and processes mentioned can be used towards prioritizing the watersheds for development, management and conservation planning.

Radionuclide and contaminant immobilization in the fluidized bed steam reforming waste products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neeway, James J.; Qafoku, Nikolla; Westsik, Joseph H.

2012-05-01

The goal of this chapter is to introduce the reader to the Fluidized Bed Steam Reforming (FBSR) process and resulting waste form. The first section of the chapter gives an overview of the potential need for FBSR processing in nuclear waste remediation followed by an overview of the engineering involved in the process itself. This is followed by a description of waste form production at a chemical level followed by a section describing different process streams that have undergone the FBSR process. The third section describes the resulting mineral product in terms of phases that are present and the abilitymore » of the waste form to encapsulate hazardous and radioactive wastes from several sources. Following this description is a presentation of the physical properties of the granular and monolith waste form product including and contaminant release mechanisms. The last section gives a brief summary of this chapter and includes a section on the strengths associated with this waste form and the needs for additional data and remaining questions yet to be answered. The reader is directed elsewhere for more information on other waste forms such as Cast Stone (Lockrem, 2005), Ceramicrete (Singh et al., 1997, Wagh et al., 1999) and geopolymers (Kyritsis et al., 2009; Russell et al., 2006).« less

Effect of palatal form on movement of teeth during processing of complete denture prosthesis: An in-vitro study.

PubMed

Babu, Sumanth; Manjunath, Shaurya; Vajawat, Mayuri

2016-01-01

The aim of this in-vitro study was to assess the influence of shallow and deep palatal forms on the movement of teeth during the processing of complete denture prosthesis. Maxillary casts with shallow and deep palatal forms were selected and duplicated to make 10 casts of each palatal form. Base plates were constructed and teeth were arranged in their anatomic positions. Metal pins with true apex were placed on the central groove of the right and left first molars and one on the incisive papilla area as a reference point. Casts were scanned using i-CAT Vision Q 1.9 (i-CAT cone beam 3D dental imaging system by Imaging Sciences International, PA, USA), which has 360° rotational tomography. The distances between the apices of metallic pin inserts on the teeth and fitted point of reference were recorded in buccopalatal axes at waxed up stage, after deflasking, and after finishing and polishing. Results showed a statistically significant movement of teeth in shallow and deep palatal forms during all stages of complete denture processing. In shallow palatal form dentures, there was a significant tooth movement in palatal direction between Stages 1 and 2 (P ≤ 0.05) and buccal movement between Stages 2 and 3. In deep palatal form dentures, teeth showed a statistically significant (P ≤ 0.05) movement in buccal direction during all stages of denture processing. Teeth showed significant movement during processing of acrylic resin dentures. Overall, the movement of teeth in shallow palatal form dentures was in palatal direction, whereas in deep palatal form dentures, the movement of teeth was in buccal direction.

75 FR 2888 - Agency Information Collection Activities: Proposed Collection; Comments Requested

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-19

... has expired, State Court Processing Statistics 2009. The Department of Justice, Office of Justice... which OMB approval has expired, State Court Processing Statistics, 2009. (2) The title of the form/collection: State Court Processing Statistics, 2009. (3) The agency form number, if any, and the applicable...

The Judicial Process as a Form of Program Evaluation.

ERIC Educational Resources Information Center

Ellsberry, James

1980-01-01

Maintaining that the judicial process is particularly effective as a form of program evaluation, this article details organizational procedures and lists the following advantages for use of the judicial process: issues are investigated in an open forum, the community can participate, and exciting opportunities for teaching and learning are…

Investigating Resulting Residual Stresses during Mechanical Forming Process

NASA Astrophysics Data System (ADS)

Akinlabi, Stephen A.; Fatoba, Olawale S.; Mashinini, Peter M.; Akinlabi, Esther T.

2018-03-01

Most manufacturing processes such as machining, welding, heat treatment, laser forming, laser cladding and, laser metal deposition, etc. are subjected to a form of heat or energy to change the geometrical shape thus changing the inherent engineering and structural properties of the material. These changes often cause the development of locked up stresses referred to as residual stresses as a result of these activities. This study reports on the residual stresses developed due to the mechanical forming process to maintain a suitable structural integrity for the formed components. The result of the analysis through the X-ray diffraction confirmed that residual stresses were induced in the manufactured parts and further revealed that residual stresses were compressive in nature as found in the parent material but with values less than the parent material.

An Extension of SIC Predictions to the Wiener Coactive Model

PubMed Central

Houpt, Joseph W.; Townsend, James T.

2011-01-01

The survivor interaction contrasts (SIC) is a powerful measure for distinguishing among candidate models of human information processing. One class of models to which SIC analysis can apply are the coactive, or channel summation, models of human information processing. In general, parametric forms of coactive models assume that responses are made based on the first passage time across a fixed threshold of a sum of stochastic processes. Previous work has shown that that the SIC for a coactive model based on the sum of Poisson processes has a distinctive down-up-down form, with an early negative region that is smaller than the later positive region. In this note, we demonstrate that a coactive process based on the sum of two Wiener processes has the same SIC form. PMID:21822333

An Extension of SIC Predictions to the Wiener Coactive Model.

PubMed

Houpt, Joseph W; Townsend, James T

2011-06-01

The survivor interaction contrasts (SIC) is a powerful measure for distinguishing among candidate models of human information processing. One class of models to which SIC analysis can apply are the coactive, or channel summation, models of human information processing. In general, parametric forms of coactive models assume that responses are made based on the first passage time across a fixed threshold of a sum of stochastic processes. Previous work has shown that that the SIC for a coactive model based on the sum of Poisson processes has a distinctive down-up-down form, with an early negative region that is smaller than the later positive region. In this note, we demonstrate that a coactive process based on the sum of two Wiener processes has the same SIC form.

Control of anisotropic shape deviation in single point incremental forming of paperboard

NASA Astrophysics Data System (ADS)

Stein, Philipp; Franke, Wilken; Hoppe, Florian; Hesse, Daniel; Mill, Katharina; Groche, Peter

2017-10-01

The increasing social demand for sustainable material use leads to new process strategies as well as to the use of new materials in nearly all industries. In light of this demand, paperboard shows potential to substitute polymer-based components while also exhibiting improved ecological properties. However, in contrast to polymer-based products, the forming limits of paperboard are relatively low. Therefore, three dimensional forming of paperboard is subject of current research. One area of research focuses on the control of the fiber orientation dependent anisotropic material behavior of industrial paperboard in forming processes. For an examined industrial paperboard, an average elongation at break of 1.2% in the so called machine direction (fiber preferential direction, MD) has been determined at standard climate conditions. In contrast, in cross-direction (orthogonal to the machine direction, CD) a value of 2.6% was observed. With increased moisture content of the specimens the difference between the mechanical properties in MD and CD even increases. As a result of the various fiber-orientation dependent mechanical properties, forming with symmetric tools leads to asymmetrically shaped final parts. Within this article, an approach to reduce the asymmetric shape of three-dimensional formed paperboard by using single point incremental forming technology is presented. For a free spatial processing strategy the 3D Servo Press Technology, which enables circular as well as free processing strategies, is used. Based on reference tests with a circular processing strategy, it is shown that by using an adapted, elliptical tool path, an almost symmetric shaped part can be formed.

Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components

NASA Technical Reports Server (NTRS)

Zimmerman, Frank R.

2001-01-01

The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center has developed and demonstrated a fabrication technique using the VPS process to form anode sections for a Lorentz force accelerator from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and accelerates the metal powder onto the mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions of the inside surface of the anode. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of the Lorentz force accelerator.

Lexical Competition Effects in Aphasia: Deactivation of Lexical Candidates in Spoken Word Processing

ERIC Educational Resources Information Center

Janse, Esther

2006-01-01

Research has shown that Broca's and Wernicke's aphasic patients show different impairments in auditory lexical processing. The results of an experiment with form-overlapping primes showed an inhibitory effect of form-overlap for control adults and a weak inhibition trend for Broca's aphasic patients, but a facilitatory effect of form-overlap was…

Joking Culture: The Role of Repeated Humorous Interactions on Group Processes during Challenge Course Experiences

ERIC Educational Resources Information Center

Rothwell, Erin; Siharath, Kassidy; Bell, Steven; Nguyen, Kim; Baker, Carla

2011-01-01

When groups form, they develop their own culture from the shared meaning created from their interactions. Humor is part of every social group, and when repeatedly referenced, it forms a joking culture. The joking culture of small groups influences group processes by smoothing group interaction, forming a collective identity, separating the group…

Influence of inductive heating on microstructure and material properties in roll forming processes

NASA Astrophysics Data System (ADS)

Guk, Anna; Kunke, Andreas; Kräusel, Verena; Landgrebe, Dirk

2017-10-01

The increasing demand for sheet metal parts and profiles with enhanced mechanical properties by using high and ultra-high-strength (UHS) steels for the automotive industry must be covered by increasing flexibility of tools and machines. This can be achieved by applying innovative technologies such as roll forming with integrated inductive heating. This process is similar to indirect press hardening and can be used for the production of hardened profiles and profiles with graded properties in longitudinal and traverse direction. The advantage is that the production of hardened components takes place in a continuous process and the integration of heating and quenching units in the profiling system increases flexibility, accompanied by shortening of the entire process chain and minimizing the springback risk. The features of the mentioned process consists of the combination of inhomogeneous strain distribution over the stripe width by roll forming and inhomogeneity of microstructure by accelerated inductive heating to austenitizing temperature. Therefore, these two features have a direct influence on the mechanical properties of the material during forming and hardening. The aim of this work is the investigation of the influence of heating rates on microstructure evolution and mechanical properties to determine the process window. The results showed that heating rate should be set at 110 K/s for economic integration of inductive heating into the roll forming process.

Robust Design of Sheet Metal Forming Process Based on Kriging Metamodel

NASA Astrophysics Data System (ADS)

Xie, Yanmin

2011-08-01

Nowadays, sheet metal forming processes design is not a trivial task due to the complex issues to be taken into account (conflicting design goals, complex shapes forming and so on). Optimization methods have also been widely applied in sheet metal forming. Therefore, proper design methods to reduce time and costs have to be developed mostly based on computer aided procedures. At the same time, the existence of variations during manufacturing processes significantly may influence final product quality, rendering non-robust optimal solutions. In this paper, a small size of design of experiments is conducted to investigate how a stochastic behavior of noise factors affects drawing quality. The finite element software (LS_DYNA) is used to simulate the complex sheet metal stamping processes. The Kriging metamodel is adopted to map the relation between input process parameters and part quality. Robust design models for sheet metal forming process integrate adaptive importance sampling with Kriging model, in order to minimize impact of the variations and achieve reliable process parameters. In the adaptive sample, an improved criterion is used to provide direction in which additional training samples can be added to better the Kriging model. Nonlinear functions as test functions and a square stamping example (NUMISHEET'93) are employed to verify the proposed method. Final results indicate application feasibility of the aforesaid method proposed for multi-response robust design.

Developing an experimental case in aluminium foils 1100 to determine the maximum angle of formability in a piece by Dieless-SPIF process

NASA Astrophysics Data System (ADS)

Gabriel, Paramo; Adrian, Benitez

2014-07-01

Incremental sheet forming by the method of single point incremental forming Dieless-SPIF, is a widely studied process, experimented and developed in countries with high manufacturing technologies, with friendly costs when the productive configuration in a productivity system is based in small production batches. United states, United kingdom and France lead this type of studies and cases, developing various proof with experimental geometries, different from the national environment such as Colombia, Bolivia, Chile, Ecuador and Peru where this process where discretely studied. Previously mentioned, it pretends develop an experimental case of a particular geometry, identifying the maximum formability angle of material permissible for the forming of a piece in one pass, the analysis of forming limit curve (FLC), with the objective to emphasizes in this innovative method based in CAD-CAM technologies, compare with other analogous process of deformation sheet metal like embossing, take correct decisions about the viability and applicability of this process (Dieless) in a particular industrial piece, which responses to the necessities of productive configurations mentioned and be highly taken like a manufacturing alternative to the other conventional process of forming sheet metal like embossing, for systems with slow batches production.

Informed consent recall and comprehension in orthodontics: traditional vs improved readability and processability methods.

PubMed

Kang, Edith Y; Fields, Henry W; Kiyak, Asuman; Beck, F Michael; Firestone, Allen R

2009-10-01

Low general and health literacy in the United States means informed consent documents are not well understood by most adults. Methods to improve recall and comprehension of informed consent have not been tested in orthodontics. The purposes of this study were to evaluate (1) recall and comprehension among patients and parents by using the American Association of Orthodontists' (AAO) informed consent form and new forms incorporating improved readability and processability; (2) the association between reading ability, anxiety, and sociodemographic variables and recall and comprehension; and (3) how various domains (treatment, risk, and responsibility) of information are affected by the forms. Three treatment groups (30 patient-parent pairs in each) received an orthodontic case presentation and either the AAO form, an improved readability form (MIC), or an improved readability and processability (pairing audio and visual cues) form (MIC + SS). Structured interviews were transcribed and coded to evaluate recall and comprehension. Significant relationships among patient-related variables and recall and comprehension explained little of the variance. The MIC + SS form significantly improved patient recall and parent recall and comprehension. Recall was better than comprehension, and parents performed better than patients. The MIC + SS form significantly improved patient treatment comprehension and risk recall and parent treatment recall and comprehension. Patients and parents both overestimated their understanding of the materials. Improving the readability of consent materials made little difference, but combining improved readability and processability benefited both patients' recall and parents' recall and comprehension compared with the AAO form.

Process for producing silicon

DOEpatents

Olson, J.M.; Carleton, K.L.

1982-06-10

A process of producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

Process for producing silicon

DOEpatents

Olson, Jerry M.; Carleton, Karen L.

1984-01-01

A process for producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

Numerical investigation for formability of aluminum 6016 alloy under non-isothermal warm forming process

NASA Astrophysics Data System (ADS)

Hu, P.; Dai, M. H.; Ying, L.; Shi, D. Y.; Zhao, K. M.; Lu, J. D.

2013-05-01

The warm forming technology of aluminum alloy has attracted attention from worldwide automotive engineering sector in recent years, with which the complex geometry parts can be realized at elevated temperature. A non-isothermal warm forming process for the heat treatable aluminum can quickly carry out its application on traditional production line by adding a furnace to heat up the aluminum alloy sheet. The 6000 aluminum alloy was investigated by numerical simulation and experiment using the Nakajima test model in this paper. A modified Fields-Backofen model was introduced into numerical simulation process to describe the thermo-mechanical flow behavior of a 6000 series aluminum alloy. The experimental data was obtained by conducting thermal-mechanical uniaxial tensile experiment in temperatures range of 25˜400°C to guarantee the numerical simulation more accurate. The numerical simulation was implemented with LS_DYNA software in terms of coupled dynamic explicit method for investigating the effect of initial forming temperature and the Binder Holder Force (BHF), which are critical process parameters in non-isothermal warm forming. The results showed that the optimal initial forming temperature range was 300°C˜350°C. By means of conducting numerical simulation in deep drawing box model, the forming window of BHF and temperature around the optimal initial forming temperature (275°, 300° and 325°) are investigated, which can provide guidance to actual experiment.

The Emergence of Primary Anoetic Consciousness in Episodic Memory

PubMed Central

Vandekerckhove, Marie; Bulnes, Luis Carlo; Panksepp, Jaak

2014-01-01

Based on an interdisciplinary perspective, we discuss how primary-process, anoetic forms of consciousness emerge into higher forms of awareness such as knowledge-based episodic knowing and self-aware forms of higher-order consciousness like autonoetic awareness. Anoetic consciousness is defined as the rudimentary state of affective, homeostatic, and sensory-perceptual mental experiences. It can be considered as the autonomic flow of primary-process phenomenal experiences that reflects a fundamental form of first-person “self-experience,” a vastly underestimated primary form of phenomenal consciousness. We argue that this anoetic form of evolutionarily refined consciousness constitutes a critical antecedent that is foundational for all forms of knowledge acquisition via learning and memory, giving rise to a knowledge-based, or noetic, consciousness as well as higher forms of “awareness” or “knowing consciousness” that permits “time-travel” in the brain-mind. We summarize the conceptual advantages of such a multi-tiered neuroevolutionary approach to psychological issues, namely from genetically controlled primary (affective) and secondary (learning and memory), to higher tertiary (developmentally emergent) brain-mind processes, along with suggestions about how affective experiences become more cognitive and object-oriented, allowing the developmental creation of more subtle higher mental processes such as episodic memory which allows the possibility of autonoetic consciousness, namely looking forward and backward at one’s life and its possibilities within the “mind’s eye.” PMID:24427125

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jinsong; Dong, Qingfeng; Sao, Yuchuan

Continuous processes for fabricating a perovskite device are described that include using a doctor blade for continuously forming a perovskite layer and using a conductive tape lamination process to form an anode or a cathode layer on the perovskite device.

Experimental Procedure for Warm Spinning of Cast Aluminum Components.

PubMed

Roy, Matthew J; Maijer, Daan M

2017-02-01

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed.

Wrapping process for fabrication of A-15 superconducting composite wires

DOEpatents

Suenaga, M.; Klamut, C.J.; Luhman, T.S.

1980-08-15

A method for fabricating superconducting wires wherein a billet of copper containing filaments of niobium or vanadium is rolled to form a strip which is wrapped about a tin-alloy core to form a composite. The alloy is a tin-copper alloy for niobium filaments and a gallium-copper alloy for vanadium filaments. The composite is then drawn down to a desired wire size and heat treated. During the heat treatment process, the tin in the bronze reacts with the niobium to form the superconductor niobium tin. In the case where vanadium is used, the gallium in the gallium bronze reacts with the vanadium to form the superconductor vanadium gallium. This new process eliminates the costly annealing steps, external tin plating and drilling of bronze ingots required in a number of prior art processes.

Experimental Procedure for Warm Spinning of Cast Aluminum Components

PubMed Central

Roy, Matthew J.; Maijer, Daan M.

2017-01-01

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed. PMID:28190063

Study of mould design and forming process on advanced polymer-matrix composite complex structure

NASA Astrophysics Data System (ADS)

Li, S. J.; Zhan, L. H.; Bai, H. M.; Chen, X. P.; Zhou, Y. Q.

2015-07-01

Advanced carbon fibre-reinforced polymer-matrix composites are widely applied to aviation manufacturing field due to their outstanding performance. In this paper, the mould design and forming process of the complex composite structure were discussed in detail using the hat stiffened structure as an example. The key issues of the moulddesign were analyzed, and the corresponding solutions were also presented. The crucial control points of the forming process such as the determination of materials and stacking sequence, the temperature and pressure route of the co-curing process were introduced. In order to guarantee the forming quality of the composite hat stiffened structure, a mathematical model about the aperture of rubber mandrel was introduced. The study presented in this paper may provide some actual references for the design and manufacture of the important complex composite structures.

Extended forms of the second law for general time-dependent stochastic processes.

PubMed

Ge, Hao

2009-08-01

The second law of thermodynamics represents a universal principle applicable to all natural processes, physical systems, and engineering devices. Hatano and Sasa have recently put forward an extended form of the second law for transitions between nonequilibrium stationary states [Phys. Rev. Lett. 86, 3463 (2001)]. In this paper we further extend this form to an instantaneous interpretation, which is satisfied by quite general time-dependent stochastic processes including master-equation models and Langevin dynamics without the requirements of the stationarity for the initial and final states. The theory is applied to several thermodynamic processes, and its consistence with the classical thermodynamics is shown.

[Effects on phenol removal in the process of enhanced coagulation by manganese dioxide formed in situ].

PubMed

Zhang, Li-Zhu; Chen, Xiao-Dong; Ma, Jun; Yu, Min; Li, Xin

2011-10-01

Phenol was selected as a model compound. Factors, such as Ca2+, tannic acid, dose of kaolinite, dose of manganese dioxide formed in situ and pH, were invested on phenol removal in the process of enhanced coagulation by manganese dioxide formed in situ. Results showed that the addition of Ca2+ is beneficial for phenol removal. In the range of Ca2+ varied from 0 to 1.0 mmol x L(-1), the efficiency of phenol removal was enhanced more than 10%. Tannic acid can enhance phenol removal significantly when they are coexisted in water. As tannic acid was added to 10 mg x L(-1), phenol removal can be increased about 30% and 50% in the process of coagulation by AlCl3 and enhanced coagulation by manganese dioxide formed in situ, respectively. The dose of coagulant can be reduced in the process of enhanced coagulation with the addition of manganese dioxide formed in situ. The point of 1 mg x L(-1) manganese dioxide formed in situ linked with 30 mg x L(-1) AlCl3 can have the same phenol removal efficiency as the addition of 50 mg x L(-1) AlCl3. In the range of pH varied from 5 to 9, phenol can be removed with the high efficiency in the process of enhanced coagulation by manganese dioxide formed in situ. While under the strong acid condition and strong basic condition, phenol has lower removal efficiency.

The RAPID method for blood processing yields new insight in plasma concentrations and molecular forms of circulating gut peptides.

PubMed

Stengel, Andreas; Keire, David; Goebel, Miriam; Evilevitch, Lena; Wiggins, Brian; Taché, Yvette; Reeve, Joseph R

2009-11-01

The correct identification of circulating molecular forms and measurement of peptide levels in blood entails that the endocrine peptide being studied is stable and recovered in good yields during blood processing. However, it is not clear whether this is achieved in studies using standard blood processing. Therefore, we compared peptide concentration and form of 12 (125)I-labeled peptides using the standard procedure (EDTA-blood on ice) and a new method employing Reduced temperatures, Acidification, Protease inhibition, Isotopic exogenous controls, and Dilution (RAPID). During standard processing there was at least 80% loss for calcitonin-gene-related peptide and cholecystokinin-58 (CCK-58) and more than 35% loss for amylin, insulin, peptide YY forms (PYY((1-36)) and PYY((3-36))), and somatostatin-28. In contrast, the RAPID method significantly improved the recovery for 11 of 12 peptides (P < 0.05) and eliminated the breakdown of endocrine peptides occurring after standard processing as reflected in radically changed molecular forms for CCK-58, gastrin-releasing peptide, somatostatin-28, and ghrelin. For endogenous ghrelin, this led to an acyl/total ghrelin ratio of 1:5 instead of 1:19 by the standard method. These results show that the RAPID method enables accurate assessment of circulating gut peptide concentrations and forms such as CCK-58, acylated ghrelin, and somatostatin-28. Therefore, the RAPID method represents an efficacious means to detect circulating variations in peptide concentrations and form relevant to the understanding of physiological function of endocrine peptides.

Investigation on thixojoining to produce hybrid components with intermetallic phase

NASA Astrophysics Data System (ADS)

Seyboldt, Christoph; Liewald, Mathias

2018-05-01

Current research activities at the Institute for Metal Forming Technology of the University of Stuttgart are focusing on the manufacturing of hybrid components using semi-solid forming strategies. One process investigated is the joining of different materials in the semi-solid state and is so called "thixojoining". In this process, metallic inlays are inserted into the semi-solid forming die before the actual forming process and are then joined with a material which was heated up to its semi-solid state. Earlier investigations have shown that using this process a very well-shaped form closure can be produced. Furthermore, it was found that sometimes intermetallic phases are built between the different materials, which decisively influence the part properties of such hybrid components for its future application. Within the framework presented in this paper, inlays made of aluminum, brass and steel were joined with aluminum in the semi-solid state. The aim of the investigations was to create an intermetallic bond between the different materials. For this investigations the liquid phase fraction of the aluminum and the temperature of the inlay were varied in order to determine the influence on the formation of the intermetallic phase. Forming trials were performed using a semi-solid forming die with a disk shaped design. Furthermore, the intermetallic phase built was investigated using microsections.

X-ray powder diffractometry of intact film coated tablets--an approach to monitor the physical form of the active pharmaceutical ingredient during processing and storage.

PubMed

Yamada, Hiroyuki; Suryanarayanan, Raj

2007-08-01

The antiviral compound, 2-amino-6-(4-methoxyphenylthio)-9-[2-(phosphonomethoxy)ethyl]purine bis(2,2,2-trifluoroethyl)ester (MCC-478), can exist in several anhydrous polymorphic forms and also as a hemihydrate. The XRD patterns of the tablets, containing each form of the active pharmaceutical ingredient (API), revealed at least one peak unique to each form. A semiquantitative microdiffractometric method was developed to nondestructively characterize the physical form of the API in intact film-coated tablets. This was accomplished even though the weight fraction of the API was <0.2 and that of mannitol, a highly crystalline excipient, was approximately 0.6. The method was used to determine the effect of aqueous film-coating process on the physical form of the API. The final dosage form was also monitored following storage at 40 degrees C/75% RH for 6 months. There was no phase transformation of the API either due to the film-coating process or following accelerated storage. This technique has potential utility not only for process control during manufacture, but also for the quality control of the final product. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

Development of a 2-stage shear-cutting-process to reduce cut-edge-sensitivity of steels

NASA Astrophysics Data System (ADS)

Gläsner, T.; Sunderkötter, C.; Hoffmann, H.; Volk, W.; Golle, R.

2017-09-01

The edge cracking sensitivity of AHSS and UHSS is a challenging factor in the cold forming process. Expanding cut holes during flanging operations is rather common in automotive components. During these flanging operations the pierced hole is stretched so that its diameter is increased. These flanging operations stretch material that has already been subjected to large amounts of plastic deformation, therefore forming problems may occur. An innovative cutting process decreases micro cracks in the cutting surface and facilitates the subsequent cold forming process. That cutting process consists of two stages, which produces close dimensional tolerance and smooth edges. As a result the hole expanding ratio was increased by nearly 100 % when using thick high strength steels for suspension components. The paper describes the mechanisms of the trimming process at the cut edge, and the positive effect of the 2-stage shear-cutting process on the hole extension capability of multiphase steels.

Electrochemical formation of field emitters

DOEpatents

Bernhardt, A.F.

1999-03-16

Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

[Current situations and problem analysis of influencing factors of traditional Chinese medicine tablets on forming quality].

PubMed

Li, Yan-Nian; Wu, Zhen-Feng; Wan, Na; Li, Yuan-Hui; Li, Hui-Ting; Yang, Ming

2018-04-01

The compressibility of tablets is the essential operating unit during the preparation of traditional Chinese medicine tablets, as well as a complicated process. Therefore, it is of great significance to comprehensively study the influencing factors on the formation process. This paper aimed to review the evaluation methods for the tablet forming quality and highlight the effects of material powder properties, excipients and preparation technology on the quality of traditional Chinese medicine tablets on the basis of relevant literatures. Furthermore, the common problems in tablet forming process are also analyzed to provide useful references for the development of tablet forming quality of traditional Chinese medicines. Copyright© by the Chinese Pharmaceutical Association.

Apparatus for electrical-assisted incremental forming and process thereof

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roth, John; Cao, Jian

A process and apparatus for forming a sheet metal component using an electric current passing through the component. The process can include providing an incremental forming machine, the machine having at least one arcuate tipped tool and at least electrode spaced a predetermined distance from the arcuate tipped tool. The machine is operable to perform a plurality of incremental deformations on the sheet metal component using the arcuate tipped tool. The machine is also operable to apply an electric direct current through the electrode into the sheet metal component at the predetermined distance from the arcuate tipped tool while themore » machine is forming the sheet metal component.« less

Leveraging health information exchange to improve population health reporting processes: lessons in using a collaborative-participatory design process.

PubMed

Revere, Debra; Dixon, Brian E; Hills, Rebecca; Williams, Jennifer L; Grannis, Shaun J

2014-01-01

Surveillance, or the systematic monitoring of disease within a population, is a cornerstone function of public health. Despite significant investment in information technologies (IT) to improve the public's health, health care providers continue to rely on manual, spontaneous reporting processes that can result in incomplete and delayed surveillance activities. Participatory design principles advocate including real users and stakeholders when designing an information system to ensure high ecological validity of the product, incorporate relevance and context into the design, reduce misconceptions designers can make due to insufficient domain expertise, and ultimately reduce barriers to adoption of the system. This paper focuses on the collaborative and informal participatory design process used to develop enhanced, IT-enabled reporting processes that leverage available electronic health records in a health information exchange to prepopulate notifiable-conditions report forms used by public health authorities. Over nine months, public health stakeholders, technical staff, and informatics researchers were engaged in a multiphase participatory design process that included public health stakeholder focus groups, investigator-engineering team meetings, public health survey and census regarding high-priority data elements, and codesign of exploratory prototypes and final form mock-ups. A number of state-mandated report fields that are not highly used or desirable for disease investigation were eliminated, which allowed engineers to repurpose form space for desired and high-priority data elements and improve the usability of the forms. Our participatory design process ensured that IT development was driven by end user expertise and needs, resulting in significant improvements to the layout and functionality of the reporting forms. In addition to informing report form development, engaging with public health end users and stakeholders through the participatory design process provided new insights into public health workflow and allowed the team to quickly triage user requests while managing user expectations within the realm of engineering possibilities. Engaging public health, engineering staff, and investigators in a shared codesigning process ensured that the new forms will not only meet real-life needs but will also support development of a product that will be adopted and, ultimately, improve communicable and infectious disease reporting by clinicians to public health.

Commentary: Should Gender Differences Be Included in the Evolutionary Upgrade to Cognitive Load Theory?

ERIC Educational Resources Information Center

Bevilacqua, Andy

2017-01-01

Recent upgrades to cognitive load theory suggest that evolutionary processes have shaped the way that working memory processes cultural and social information. According to evolutionarily educational psychologists, some forms of information are processed with lower working memory loads than other forms. The former are evolutionarily salient and…

77 FR 6125 - Agency Information Collection Activities: Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-07

... services requesting participation in the Medicare program. This form initiates the process of obtaining a... promotes data reduction or introduction to and retrieval from the Automated Survey Process Environment... clinic data as a part of the RHC certification process. Therefore, the revised title is ``Form CMS-29...

Improvement of the functional properties of nanostructured Ti-Ni shape memory alloys by means of thermomechanical processing

NASA Astrophysics Data System (ADS)

Kreitcberg, Alena

Severe plastic deformation (SPD) is commonly used for nanostructure formation in Ti-Ni shape memory alloys (SMAs), but it increases the risk of damage during processing and, consequently, negatively affects functional fatigue resistance of these materials. The principal objective of this project is, therefore, to study the interrelations between the processing conditions, damageability during processing, microstructure and the functional properties of Ti-Ni SMAs with the aim of improving long-term functional performances of these materials by optimizing their processing conditions. First, microstructure and fatigue properties of Ti-Ni SMAs were studied after thermomechanical treatment (TMT) with different combinations of severe cold and warm rolling (CR and WR), as well as intermediate and post-deformation annealing (IA and PDA) technological steps. It was shown that either when WR and IA were introduced into the TMT schedule, or CR intensity was decreased, the fatigue life was improved as a consequence of less processing-induced damage and higher density of the favorable B2-austenite texture. This improvement was reached, however, at a price of a lower multi-cycle functional stability of these materials, the latter being a direct consequence of the microstructure coarsening after higher-temperature lower-intensity processing. At the end of this study, however, it was not possible to distinguish between contributions to the functional performances of Ti-Ni SMAs from different processing-related features: a) grain/subgrain size; b) texture; and c) level of rolling-induced defects. To be capable of separating contributions to the functional properties of Ti-Ni alloys from grain/subgrain size and from texture, the theoretical crystallographic resource of recovery strain after different TMTs and, therefore, different textures, were calculated and compared with the experiment. The comparative analysis showed that the structural factors (grain/subgrain size) strongly dominate the texture contributions, and therefore, there is no real alternative to having nanocrystalline Ti-Ni alloys, if one needs to maximize the Ti-Ni alloys functional properties. Since the creation of such a microstructure requires the use of severe cold deformation techniques and neither of these techniques can be completely exempt from defects, it was deemed necessary to compare the damage tolerance of nanocrystalline Ti-Ni alloys to that of their nanosubgrained and mixed nanocrystalline/nanosubgrained counterparts. With this objective in mind, a detailed analysis of interrelations between the level of the CR/WR-induced damage (edge microcrack size and concentration) and the fatigue life of Ti- Ni SMAs was carried out. It was shown that nanocrystalline structure provides higher tolerance to small-crack propagation than nanosubgrained or mixed nanocrystalline/ nanosubgrained structures, and that low-temperature deformability of these alloys has to be improved to benefit from the property-enhancement potential of nanocrystalline structure. To broaden our knowledge in the field of Ti-Ni alloy deformability, the strain-rate sensitivity of these alloys was studied. Different microstructures, varying from the coarse- to ultrafinegrained, were created by means of equal-channel angular pressing (ECAP) and subjected to strain-rate sensitivity testing. As a result, the material with ultrafine-grained microstructure demonstrated an improved deformability as compared to the coarse-grained structure, at any deformation temperature. Moreover, it was determined that the smaller the grain size, the lower the temperature and the higher the strain-rate at which superplasticity occurs. Based on the results obtained, combined thermomechanical processing (ECAP at elevated temperatures followed by CR) was proposed and validated in terms of structural refinement with reduced level of processing-induced defects. Scientific contributions. This thesis contributes to the advancement of knowledge in the field of Ti-Ni SMAs' processing-structure-properties interactions, and the main conclusions of this study can be summed-up as follows: • Nanocrystalline Ti-Ni alloys significantly outperform nanosubgrain Ti-Ni alloys in terms of the absolute values and stability of their single- and multiple-cycle functional properties (superelasticity and shape memory characteristics). The main factor limiting the number of cycles to failure of the nanocrystalline alloys is the processingrelated damage. • The structure of Ti-Ni alloys plays significantly higher role in the realization of their functional potential that does their texture. • In terms of fatigue life, the nanocrystalline structure has lower small-crack sensitivity than does the nanosubgrained structure. • Grain refinement makes it possible to improve deformability of Ti-Ni alloys at any temperature. • To produce nanocrystalline Ti-Ni SMAs free of processing-induced-defects, a novel three-step processing is proposed (ECAP+CR+PDA): grain-refining severe plastic deformation at elevated temperatures (ECAP), followed-up by amorphizing SPD at low temperatures (CR), and ended-up by nanocrystallizing post-deformation heat treatment (PDA).

76 FR 53763 - Immigration Benefits Business Transformation, Increment I

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-29

...The Department of Homeland Security (DHS) is amending its regulations to enable U.S. Citizenship and Immigration Services (USCIS) to migrate from a paper file-based, non-integrated systems environment to an electronic customer-focused, centralized case management environment for benefit processing. This transformation process will allow USCIS to streamline benefit processing, eliminate the capture and processing of redundant data, and reduce the number of and automate its forms. This transformation process will be a phased multi-year initiative to restructure USCIS business processes and related information technology systems. DHS is removing references to form numbers, form titles, expired regulatory provisions, and descriptions of internal procedures, many of which will change during transformation. DHS is also finalizing interim rules that permitted submission of benefit requests with an electronic signature when such requests are submitted in an electronic format rather than on a paper form and that removed references to filing locations for immigration benefits. In addition, in this rule DHS is publishing the final rule for six other interim rules published during the past several years, most of which received no public comments.

Importance of material and friction characterisation for FE-aided process design of hybrid bevel gears

NASA Astrophysics Data System (ADS)

Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Matthias, T.

2017-10-01

Solid-forming components are often used in areas where they are subjected to very high loads. For most solid components locally divergent and sometimes contradictory requirements exist. Despite these contradictory requirements, almost exclusively monomaterials are nowadays used for the production of solid components. These components often reach their material-specific limits because of increasing demands on the products. Thus a significant increase in product quality and profitability would result from combining different materials in order to create tailored properties. In the Collaborative Research Center (CRC) 1153 "Tailored Forming" at the Leibniz Universität Hannover, this topic is investigated. The primary objective of the CRC 1153 is to develop and investigate new tailored manufacturing processes to produce reliable hybrid solid semi-finished components. In contrast to existing production processes of hybrid solid components, semi-finished workpieces in the CRC 1153 are joined before the forming phase. Thus, it will be possible to produce complex and highly stressable solid components made of different metals, which cannot be produced yet with the current used technologies. In this work the material and friction characteristics are investigated and the forming tool for the production of hybrid bevel gears made of different steel alloys (C22 and 41Cr4) is designed by numerical simulations. For this purpose, flow curves of both materials are determined by means of upsetting tests at process-related forming temperatures and strain rates. The temperature range for the forming process of the semi-finished product is determined by comparing the respective flow curves regarding similar flow stresses. Furthermore, the friction between the tool and the joining materials is investigated by means of ring upsetting tests at a process-relevant temperature. Finally, a stress analysis of the forming tools is carried out.

Thermoforming of glass fibre reinforced polypropylene: A study on the influence of different process parameters

NASA Astrophysics Data System (ADS)

Schug, Alexander; Winkelbauer, Jonas; Hinterhölzl, Roland; Drechsler, Klaus

2017-10-01

The aim of this study was to analyse the forming behaviour of glass fibre reinforced polypropylene and to identify the influence of several process parameters on the resulting part quality. For this purpose, a complex forming tool was designed, consisting of several areas with single and double curvature. The specimens were produced from unidirectional (UD) tape using the Fiberforge RELAY2000® automated tape laying machine and a subsequent consolidation step. They were then fixed in a support frame, pre-heated in an infrared oven, and formed in the forming tool, which was mounted into a hydraulic heating press. The investigated process parameters were the number and force of the springs in the support frame, the tool temperature and the forming pressure and speed. The layups of the specimens were [0/90/0/90/0¯]s and [0/45/90/-45/0¯]s. After the forming process, the parts were analysed in terms of their quality, with a special focus on wrinkles, undulations, gaps and surface roughness. In addition to optical analysis with a statistical evaluation of the results, 3D scans of the specimens at different steps of the forming process were made to gain an impression of the forming mechanisms and the development of failures. The ATOS system of GOM was used for these 3D scans. The results show that the undulations were influenced by the tool temperature and the spring force. By contrast, the surface quality was most strongly dependent on the forming pressure, which also influenced the size and the number of gaps. The forming speed affected the gaps as well. The tool temperature had the largest influence on the development of wrinkles. As expected, the quasi-isotropic layup showed distinctly more wrinkles and undulations, but it also presented a better surface quality than the orthotropic layup.

Tailoring properties of commercially pure titanium by gradation extrusion

NASA Astrophysics Data System (ADS)

Bergmann, Markus; Rautenstrauch, Anja; Selbmann, René; de Oliveira, Raoni Barreto; Coelho, Rodrigo Santiago; Landgrebe, Dirk

2016-10-01

Commercially pure titanium (CP Ti) is of great importance in medical applications due to its attractive properties, such as high biocompatibility, excellent corrosion resistance and relatively low density and suitable stiffness. Compared to the commonly used Ti-6Al-4V alloy, its lower strength has to be increased. The most attractive approach is to subject CP Ti to severe plastic deformation (SPD) processes such as Equal Channel Angular Pressing (ECAP). The resulting decreased grain size in CP Ti yields a significant increase in hardness and strength. Common SPD-processes typically provide a uniform modification of the material. Their material efficiency and productivity are critical and limiting factors. A new approach is to tailor the material properties by using Gradation Extrusion, which produces a distinct gradient in microstructure and strength. The forming process combines a regular impact extrusion process and severe plastic deformation in the lateral area of the material. This efficient process can be integrated easily into forming process chains, for instance for dental implants. This paper presents the forming process and the applied die geometry. The results of numerical simulations are used to illustrate the potential of the process to modify and strengthen the titanium material. Experiments show that the material is successfully processed by gradation extrusion. By characterizing the hardness and its distribution within the formed parts the effects of the process are investigated.

Roll forming of eco-friendly stud

NASA Astrophysics Data System (ADS)

Keum, Y. T.; Lee, S. Y.; Lee, T. H.; Sim, J. K.

2013-12-01

In order to manufacture an eco-friendly stud, the sheared pattern is designed by the Taguchi method and expanded by the side rolls. The seven geometrical shape of sheared pattern are considered in the structural and thermal analyses to select the best functional one in terms of the durability and fire resistance of dry wall. For optimizing the size of the sheared pattern chosen, the L9 orthogonal array and smaller-the-better characteristics of the Taguchi method are used. As the roll gap causes forming defects when the upper-and-lower roll type is adopted for expanding the sheared pattern, the side roll type is introduced. The stress and strain distributions obtained by the FEM simulation of roll-forming processes are utilized for the design of expanding process. The expanding process by side rolls shortens the length of expanding process and minimizes the cost of dies. Furthermore, the stud manufactured by expanding the sheared pattern of the web is an eco-friend because of the scrapless roll-forming process. In addition, compared to the conventionally roll-formed stud, the material cost is lessened about 13.6% and the weight is lightened about 15.5%.

Effect of local structures on crystallization in deeply undercooled metallic glass-forming liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, S. Q.; Li, M. Z., E-mail: maozhili@ruc.edu.cn; Wu, Z. W.

2016-04-21

The crystallization mechanism in deeply undercooled ZrCu metallic glass-forming liquids was investigated via molecular dynamics simulations. It was found that the crystallization process is mainly controlled by the growth of crystal nuclei formed by the BCC-like atomic clusters, consistent with experimental speculations. The crystallization rate is found to relate to the number of growing crystal nuclei in the crystallization process. The crystallization rate in systems with more crystal nuclei is significantly hindered by the larger surface fractions of crystal nuclei and their different crystalline orientations. It is further revealed that in the crystallization in deeply undercooled regions, the BCC-like crystalmore » nuclei are formed from the inside of the precursors formed by the FCC-like atomic clusters, and growing at the expense of the precursors. Meanwhile, the precursors are expanding at the expense of the outside atomic clusters. This process is consistent with the so-called Ostwald step rule. The atomic structures of metallic glasses are found to have significant impact on the subsequent crystallization process. In the Zr{sub 85}Cu{sub 15} system, the stronger spatial correlation of Cu atoms could hinder the crystallization processes in deeply undercooled regions.« less

Recrystallization of fluconazole using the supercritical antisolvent (SAS) process.

PubMed

Park, Hee Jun; Kim, Min-Soo; Lee, Sibeum; Kim, Jeong-Soo; Woo, Jong-Soo; Park, Jeong-Sook; Hwang, Sung-Joo

2007-01-10

The supercritical antisolvent (SAS) process was used to modify solid state characteristics of fluconazole. Fluconazole was recrystallized at various temperatures (60-80 degrees C) and pressures (8-16MPa) using dichloromethane (DCM) as a solvent. Acetone and ethanol were also employed as solvents. The fluconazole polymorphs prepared by the SAS process were characterized by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Furthermore, the equilibrium solubility of the samples in aqueous solution was determined. Fluconazole anhydrate form I was obtained at low temperature (40 degrees C) and anhydrate form II was obtained at high temperature (80 degrees C). The variation of pressure during the SAS process may influence the preferred orientation. Anhydrate forms I and II were also obtained using various solvents. Therefore, it was shown that solid state characteristics of fluconazole, including the polymorphic form and preferred orientation, can be controlled by changing operating conditions of the SAS process such as temperature, pressure, and solvent.

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR FLOW AND CUSTODY OF FIELD DATA FORMS (UA-C-5.0)

EPA Science Inventory

The purpose of this SOP is to describe the flow of field data forms through the data processing system and to define who is responsible for the data at any time. It applies to field data forms collected and processed by NHEXAS Arizona. This procedure was followed to ensure consi...

32 CFR Appendix D to Part 113 - Sample DD Form 2654, “Involuntary Allotment Notice and Processing”

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 1 2010-07-01 2010-07-01 false Sample DD Form 2654, âInvoluntary Allotment Notice and Processingâ D Appendix D to Part 113 National Defense Department of Defense OFFICE OF THE..., App. D Appendix D to Part 113—Sample DD Form 2654, “Involuntary Allotment Notice and Processing...

Multi-objective optimization of process parameters of multi-step shaft formed with cross wedge rolling based on orthogonal test

NASA Astrophysics Data System (ADS)

Han, S. T.; Shu, X. D.; Shchukin, V.; Kozhevnikova, G.

2018-06-01

In order to achieve reasonable process parameters in forming multi-step shaft by cross wedge rolling, the research studied the rolling-forming process multi-step shaft on the DEFORM-3D finite element software. The interactive orthogonal experiment was used to study the effect of the eight parameters, the first section shrinkage rate φ1, the first forming angle α1, the first spreading angle β1, the first spreading length L1, the second section shrinkage rate φ2, the second forming angle α2, the second spreading angle β2 and the second spreading length L2, on the quality of shaft end and the microstructure uniformity. By using the fuzzy mathematics comprehensive evaluation method and the extreme difference analysis, the influence degree of the process parameters on the quality of the multi-step shaft is obtained: β2>φ2L1>α1>β1>φ1>α2L2. The results of the study can provide guidance for obtaining multi-stepped shaft with high mechanical properties and achieving near net forming without stub bar in cross wedge rolling.

Method for the removal of ultrafine particulates from an aqueous suspension

DOEpatents

Chaiko, David J.; Kopasz, John P.; Ellison, Adam J. G.

2000-01-01

A method of separating ultra-fine particulates from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel containing the particulates, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

Method for the Removal of Ultrafine Particulates from an Aqueous Suspension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaiko, David J.; Kopasz, John P.; Ellison, Adam J.G.

1999-03-05

A method of separating ultra-fine particulate from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel-containing the particulate, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

Logical Form as a Determinant of Cognitive Processes

NASA Astrophysics Data System (ADS)

van Lambalgen, Michiel

We discuss a research program on reasoning patterns in subjects with autism, showing that they fail to engage in certain forms of non-monotonic reasoning that come naturally to neurotypical subjects. The striking reasoning patterns of autists occur both in verbal and in non-verbal tasks. Upon formalising the relevant non-verbal tasks, one sees that their logical form is the same as that of the verbal tasks. This suggests that logical form can play a causal role in cognitive processes, and we suggest that this logical form is actually embodied in the cognitive capacity called 'executive function'.

Alkali metal nitrate purification

DOEpatents

Fiorucci, Louis C.; Morgan, Michael J.

1986-02-04

A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1999-07-20

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1998-03-24

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Composition and process for the encapsulation and stabilization of radioactive hazardous and mixed wastes

DOEpatents

Kalb, Paul D.; Colombo, Peter

1997-01-01

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.

Cloning, preparation and preliminary crystallographic studies of penicillin V acylase autoproteolytic processing mutants

PubMed Central

Chandra, P. Manish; Brannigan, James A.; Prabhune, Asmita; Pundle, Archana; Turkenburg, Johan P.; Dodson, G. Guy; Suresh, C. G.

2005-01-01

The crystallization of three catalytically inactive mutants of penicillin V acylase (PVA) from Bacillus sphaericus in precursor and processed forms is reported. The mutant proteins crystallize in different primitive monoclinic space groups that are distinct from the crystal forms for the native enzyme. Directed mutants and clone constructs were designed to study the post-translational autoproteolytic processing of PVA. The catalytically inactive mutants will provide three-dimensional structures of precursor PVA forms, plus open a route to the study of enzyme–substrate complexes for this industrially important enzyme. PMID:16508111

Intracellular accumulation and oligosaccharide processing of alkaline phosphatase under disassembly of the Golgi complex caused by brefeldin A.

PubMed

Takami, N; Oda, K; Fujiwara, T; Ikehara, Y

1990-12-27

Electron microscopic observations showed that the fungal metabolite brefeldin A caused disassembly of the Golgi complex in human choriocarcinoma cells and accumulation of alkaline phosphatase (ALP) in the endoplasmic reticulum (ER) and nuclear envelope, where ALP was not apparently detectable in control cells. Pulse/chase experiments with [35S]methionine demonstrated that in the control cells, ALP synthesized as a 63-kDa precursor form was rapidly converted to a 66-kDa form, by processing of its N-linked oligosaccharides from the high-mannose type to the complex type, which was expressed on the cell surface after 30 min of chase. In contrast, in the brefeldin-A-treated cells the precursor was gradually converted to a 65-kDa form, slightly smaller than the control mature form, which was not expressed on the cell surface even after a prolonged time of chase. Kinetics of the ALP processing in the brefeldin-A-treated cells demonstrated that the precursor was initially converted to an intermediate form, partially sensitive to endo-beta-N-acetylglucosaminidase H (endo H), then to an endo-H-resistant 65-kDa form. In addition, this form was found to be sensitive to neuraminidase digestion, though its sialylation was not so complete as that of the control mature form. Taken together, these results suggest that under disassembly of the Golgi complex caused by brefeldin A, oligosaccharide-processing enzymes including sialyltransferase, an enzyme in the trans Golgi cisterna(e) and/or the trans Golgi network, might be redistributed into the ER and involved in processing of the oligosaccharides of ALP accumulating there.

Net Shape Spin Formed Cryogenic Aluminum Lithium Cryogenic Tank Domes for Lower Cost Higher Performance Launch Vehicles

NASA Technical Reports Server (NTRS)

Curreri, Peter A.; Hoffman, Eric; Domack, Marcia; Brewster, Jeb; Russell, Carolyn

2013-01-01

With the goal of lower cost (simplified manufacturing and lower part count) and higher performance (higher strength to weight alloys) the NASA Technical Maturation Program in 2006 funded a proposal to investigate spin forming of space launch vehicle cryogenic tank domes. The project funding continued under the NASA Exploration Technology Development Program through completion in FY12. The first phase of the project involved spin forming of eight, 1 meter diameter "path finder" domes. Half of these were processed using a concave spin form process (MT Aerospace, Augsburg Germany) and the other half using a convex process (Spincraft, Boston MA). The convex process has been used to produce the Ares Common Bulkhead and the concave process has been used to produce dome caps for the Space Shuttle light weight external tank and domes for the NASDA H2. Aluminum Lithium material was chosen because of its higher strength to weight ratio than the Aluminum 2219 baseline. Aluminum lithium, in order to obtain the desired temper (T8), requires a cold stretch after the solution heat treatment and quench. This requirement favors the concave spin form process which was selected for scale up. This paper describes the results of processing four, 5.5 meter diameter (upper stage scale) net shaped spin formed Aluminum Lithium domes. In order to allow scalability beyond the limits of foundry and rolling mills (about 12 foot width) the circular blank contained one friction stir weld (heavy lifter scales require a flat blank containing two welds). Mechanical properties data (tensile, fracture toughness, stress corrosion, and simulated service testing) for the parent metal and weld will also be discussed.

77 FR 29747 - Notice of Request for Information Collection Approval

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-18

... employment discrimination complaint form when processing Equal Employment Opportunity (EEO) discrimination.... SUPPLEMENTARY INFORMATION: Form Title: Individual Complaint of Employment Discrimination. OMB Control Number... information necessary to process EEO discrimination complaints filed by [[Page 29748

Density of Spray-Formed Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kevin M. McHugh; Volker Uhlenwinkel; Nils Ellendr

2008-06-01

Spray Forming is an advanced materials processing technology that transforms molten metal into a near-net-shape solid by depositing atomized droplets onto a substrate. Depending on the application, the spray-formed material may be used in the as-deposited condition or it may undergo post-deposition processing. Regardless, the density of the as-deposited material is an important issue. Porosity is detrimental because it can significantly reduce strength, toughness, hardness and other properties. While it is not feasible to achieve fully-dense material in the as-deposited state, density greater than 99% of theoretical density is possible if the atomization and impact conditions are optimized. Thermal conditionsmore » at the deposit surface and droplet impact angle are key processing parameters that influence the density of the material. This paper examines the factors that contribute to porosity formation during spray forming and illustrates that very high as-deposited density is achieved by optimizing processing parameters.« less

The onsite manufacture of propellant oxygen from lunar resources

NASA Technical Reports Server (NTRS)

Rosenberg, Sanders D.; Beegle, Robert L., Jr.; Guter, Gerald A.; Miller, Frederick E.; Rothenberg, Michael

1992-01-01

The Aerojet carbothermal process for the manufacture of oxygen from lunar materials has three essential steps: the reduction of silicate with methane to form carbon monoxide and hydrogen; the reduction of carbon monoxide with hydrogen to form methane and water; and the electrolysis of water to form hydrogen and oxygen. The reactions and the overall process are shown. It is shown with laboratory experimentation that the carbothermal process is feasible. Natural silicates can be reduced with carbon or methane. The important products are carbon monoxide, metal, and slag. The carbon monoxide can be completely reduced to form methane and water. The water can be electrolyzed to produce hydrogen and oxygen. A preliminary engineering study shows that the operation of plants using this process for the manufacture of propellant oxygen has a large economic advantage when the cost of the plant and its operation is compared to the cost of delivering oxygen from Earth.

Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials.

PubMed

Schupp, Harald T; Kirmse, Ursula; Schmälzle, Ralf; Flaisch, Tobias; Renner, Britta

2016-06-20

Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life.

Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials

PubMed Central

Schupp, Harald T.; Kirmse, Ursula; Schmälzle, Ralf; Flaisch, Tobias; Renner, Britta

2016-01-01

Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life. PMID:27321471

Amphitheater-Headed Valleys: Unique or Non-Unique Origin? The Hawaiian Laboratory

NASA Astrophysics Data System (ADS)

Pederson, D. T.; Blay, C.

2007-12-01

While the formation and migration of amphitheaters (knickpoints) in unconsolidated sediment is fairly well understood the same cannot be said for amphitheaters formed in a variety of bedrock types, climate settings, and even planetary location. The question remains, is there a single knickpoint forming process at work or do multiple landscape forming processes have a convergence tendency because of cybernetic feedback? A simple example would be a waterfall creating a micro-environment that enhances and focuses specific landscape forming processes like weathering, microbial action, and vegetation growth aiding in the continuation of the knickpoint form. It should be noted that weathering, microbial growth and vegetation growth would have cybernetic feedback among them. In fact it may be difficult to determine the controlling process, if any. If one considers that knickpoints likely intercept the regional groundwater flow system there is an additional focused source of water supply which further contributes to the micro-environment of the knickpoint. Groundwater discharge has significant cybernetic feedbacks with landscape forming processes. The nature and composition of the bedrock and climatic factors may determine rates of knickpoint migration but the resulting morphologic features in different settings would likely be similar with cybernetic feedback. It should be noted that cybernetic feedback can either be damping or amplifying. Amphitheater-headed valleys have developed in many locations on the Hawaiian Islands. The islands have formed in a time sequence as the supporting oceanic plate moves over a focused mantle source for the basalts. The amphitheaters of Hawaii occur in "fresh" and "older" basaltic rock depending on island location. Weathering processes have acted longer on some islands. Because of the topography and its affect on trade winds the main islands have focused rainfall, significant recharge, and active groundwater flow systems. While climate is uniform overall, the wet and dry sides of the islands coupled with topography represent multiple climatic zones. This affords the opportunity to use the Hawaiian Islands as a laboratory to study the cybernetic feedbacks among knickpoint forming processes. Feedback examples will be presented for several Hawaiian knickpoints.

Development of a low energy micro sheet forming machine

NASA Astrophysics Data System (ADS)

Razali, A. R.; Ann, C. T.; Shariff, H. M.; Kasim, N. I.; Musa, M. A.; Ahmad, A. F.

2017-10-01

It is expected that with the miniaturization of materials being processed, energy consumption is also being `miniaturized' proportionally. The focus of this study was to design a low energy micro-sheet-forming machine for thin sheet metal application and fabricate a low direct current powered micro-sheet-forming machine. A prototype of low energy system for a micro-sheet-forming machine which includes mechanical and electronic elements was developed. The machine was tested for its performance in terms of natural frequency, punching forces, punching speed and capability, energy consumption (single punch and frequency-time based). Based on the experiments, the machine can do 600 stroke per minute and the process is unaffected by the machine's natural frequency. It was also found that sub-Joule of power was required for a single stroke of punching/blanking process. Up to 100micron thick carbon steel shim was successfully tested and punched. It concludes that low power forming machine is feasible to be developed and be used to replace high powered machineries to form micro-products/parts.

41 CFR 102-37.575 - Is there a special form for holding agencies to process donations?

Code of Federal Regulations, 2010 CFR

2010-07-01

... for holding agencies to process donations? 102-37.575 Section 102-37.575 Public Contracts and Property... PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Bodies in Lieu of Abandonment/Destruction § 102-37.575 Is there a special form for holding agencies to process donations? There is no...

41 CFR 102-37.575 - Is there a special form for holding agencies to process donations?

Code of Federal Regulations, 2013 CFR

2013-07-01

... for holding agencies to process donations? 102-37.575 Section 102-37.575 Public Contracts and Property... PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Bodies in Lieu of Abandonment/Destruction § 102-37.575 Is there a special form for holding agencies to process donations? There is no...

41 CFR 102-37.575 - Is there a special form for holding agencies to process donations?

Code of Federal Regulations, 2014 CFR

2014-01-01

... for holding agencies to process donations? 102-37.575 Section 102-37.575 Public Contracts and Property... PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Bodies in Lieu of Abandonment/Destruction § 102-37.575 Is there a special form for holding agencies to process donations? There is no...

41 CFR 102-37.575 - Is there a special form for holding agencies to process donations?

Code of Federal Regulations, 2011 CFR

2011-01-01

... for holding agencies to process donations? 102-37.575 Section 102-37.575 Public Contracts and Property... PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Bodies in Lieu of Abandonment/Destruction § 102-37.575 Is there a special form for holding agencies to process donations? There is no...

41 CFR 102-37.575 - Is there a special form for holding agencies to process donations?

Code of Federal Regulations, 2012 CFR

2012-01-01

... for holding agencies to process donations? 102-37.575 Section 102-37.575 Public Contracts and Property... PROPERTY 37-DONATION OF SURPLUS PERSONAL PROPERTY Donations to Public Bodies in Lieu of Abandonment/Destruction § 102-37.575 Is there a special form for holding agencies to process donations? There is no...

Forest forming process and dynamic vegetation models under global change

Treesearch

A. Shvidenko; E. Gustafson

2009-01-01

The paper analyzes mathematical models that are used to project the dynamics of forest ecosystems on different spatial and temporal scales. Landscape disturbance and succession models (LDSMs) are of a particular interest for studying the forest forming process in Northern Eurasia. They have a solid empirical background and are able to model ecological processes under...

The peculiarities of process-based approach realization in transport sector company management

NASA Astrophysics Data System (ADS)

Khripko, Elena; Sidorov, Gennadiy

2017-10-01

In the present article we study the phenomena of multiple meaning in understanding process-based management method in construction of transport infrastructure facilities. The idea of multiple meaning is in distortions which appear during reception of the management process paradigm in organizational environment of transport sector. The cause of distortion in process management is organizational resistance. The distortions of management processes are discovered at the level of diffusion among spheres of responsibility, collision in forms of functional, project and process interaction between the owner of the process and its participants. The level of distortion is affected by the attitude towards the result of work which means that process understanding of the result is replaced by the functional one in practice of management. This transfiguration is the consequence of regressive defensive mechanisms of the organizational environment. On the base of experience of forming process management in construction of transport infrastructure facilities company of the issues of diagnostics of various forms of organizational resistance and ways of reducing the destructive influence on managing processes are reviewed.

[Anatomical and computed tomographic analysis of the interaction between uncinate process and agger nasi cells].

PubMed

Zhang, Luo; Han, De-min; Ge, Wen-tong; Zhou, Bing; Xian, Jun-fang; Liu, Zhong-yan; Wang, Kui-ji; He, Fei

2005-12-01

To investigate the anatomical interaction between uncinate process and agger nasi cell to better understand the anatomy of the frontal sinus drainage pathway by endoscopy, spiral computed tomography (CT) and sectioning. Twenty-one skeletal skulls (forty-two sides) and one cadaver head (two sides) were studied by spiral CT together with endoscopy and collodion embedded thin sectioning at coronal plane. The sections with the thickness of 100 microm were stained with hemotoxylin and eosin. Under endoscopy, a leaflet of bone to the middle turbinate, which is given off by uncinate process, forms the anterior insertion of the middle turbinate onto the lateral nasal wall. The middle portion of the uncinate process attached to the frontal process of the maxilla in all of the skeletal nasal cavities, as well as the lacrimal bone in 78.6% of the skeletal nasal cavities. On CT scans, the agger nasi cell is present in 90.5% of the skeletal nasal cavities. While the lateral wall of the agger nasi cell is formed by lacrimal bone, the medial wall of the agger nasi cell is formed by uncinate process. And the anterior wall is formed by the frontal process of the maxilla. The superior portion of the uncinate process forms the medial, posterior and top wall of the agger nasi cells. The superior portion of the uncinate extends into the frontal recess and may insert into lamina papyracea (33.3%), skull base (9.5%), middle turbinate, combination of these (57.2%). The agger nasi cell is the key that unlocks the frontal recess.

Development of forming and joining technology for TD-NiCr sheet

NASA Technical Reports Server (NTRS)

Torgerson, R. T.

1973-01-01

Forming joining techniques and properties data were developed for thin-gage TD-NiCr sheet in the recrystallized and unrecrystallized conditions. Theoretical and actual forming limit data are presented for several gages of each type of material for five forming processes: brake forming, corrugation forming, joggling, dimpling and beading. Recrystallized sheet can be best formed at room temperature, but unrecrystallized sheet requires forming at elevated temperature. Formability is satisfactory with most processes for the longitudinal orientation but poor for the transverse orientation. Dimpling techniques require further development for both material conditions. Data on joining techniques and joint properties are presented for four joining processes: resistance seam welding (solid-state), resistance spot welding (solid-state), resistance spot welding (fusion) and brazing. Resistance seam welded (solid-state) joints with 5t overlap were stronger than parent material for both material conditions when tested in tensile-shear and stress-rupture. Brazing studies resulted in development of NASA 18 braze alloy (Ni-16Cr-15Mo-8Al-4Si) with several properties superior to baseline TD-6 braze alloy, including lower brazing temperture, reduced reaction with Td-Ni-Cr, and higher stress-rupture properties.

Analysis of hot forming of a sheet metal component made of advanced high strength steel

NASA Astrophysics Data System (ADS)

Demirkaya, Sinem; Darendeliler, Haluk; Gökler, Mustafa İlhan; Ayhaner, Murat

2013-05-01

To provide reduction in weight while maintaining crashworthiness and to decrease the fuel consumption of vehicles, thinner components made of Advanced High Strength Steels (AHSS) are being increasingly used in automotive industry. However, AHSS cannot be formed easily at the room temperature (i.e. cold forming). The alternative process involves heating, hot forming and subsequent quenching. A-pillar upper reinforcement of a vehicle is currently being produced by cold forming of DP600 steel sheet with a thickness of 1.8 mm. In this study, the possible decrease in the thickness of this particular part by using 22MnB5 as appropriate AHSS material and applying this alternative process has been studied. The proposed process involves deep drawing, trimming, heating, sizing, cooling and piercing operations. Both the current production process and the proposed process are analyzed by the finite element method. The die geometry, blank holding forces and the design of the cooling channels for the cooling process are determined numerically. It is shown that the particular part made of 22MnB5 steel sheet with a thickness of 1.2 mm can be successfully produced by applying the proposed process sequence and can be used without sacrificing the crashworthiness. With the use of the 22MnB5 steel with a thickness of 1.2 mm instead of DP600 sheet metal with a thickness of 1.8 mm, the weight is reduced by approximately 33%.

The finite element simulation analysis research of 38CrSi cylindrical power spinning

NASA Astrophysics Data System (ADS)

Liang, Wei; Lv, Qiongying; Zhao, Yujuan; Lv, Yunxia

2018-01-01

In order to grope for the influence of the main cylindrical spinning process parameters on the spinning process, this paper combines with real tube power spinning process and uses ABAQUS finite element analysis software to simulate the tube power spinning process of 38CrSi steel materials, through the analysis of the stress, strain of the part forming process, analyzes the influence of the thickness reduction and the feed rate to the forming process, and analyzes the variation of the spinning force, finally determines the reasonable main spinning process parameters combination.

Experimental research and numerical optimisation of multi-point sheet metal forming implementation using a solid elastic cushion system

NASA Astrophysics Data System (ADS)

Tolipov, A. A.; Elghawail, A.; Shushing, S.; Pham, D.; Essa, K.

2017-09-01

There is a growing demand for flexible manufacturing techniques that meet the rapid changes in customer needs. A finite element analysis numerical optimisation technique was used to optimise the multi-point sheet forming process. Multi-point forming (MPF) is a flexible sheet metal forming technique where the same tool can be readily changed to produce different parts. The process suffers from some geometrical defects such as wrinkling and dimpling, which have been found to be the cause of the major surface quality problems. This study investigated the influence of parameters such as the elastic cushion hardness, blank holder force, coefficient of friction, cushion thickness and radius of curvature, on the quality of parts formed in a flexible multi-point stamping die. For those reasons, in this investigation, a multipoint forming stamping process using a blank holder was carried out in order to study the effects of the wrinkling, dimpling, thickness variation and forming force. The aim was to determine the optimum values of these parameters. Finite element modelling (FEM) was employed to simulate the multi-point forming of hemispherical shapes. Using the response surface method, the effects of process parameters on wrinkling, maximum deviation from the target shape and thickness variation were investigated. The results show that elastic cushion with proper thickness and polyurethane with the hardness of Shore A90. It has also been found that the application of lubrication cans improve the shape accuracy of the formed workpiece. These final results were compared with the numerical simulation results of the multi-point forming for hemispherical shapes using a blank-holder and it was found that using cushion hardness realistic to reduce wrinkling and maximum deviation.

Integrated Analysis of Flow, Form, and Function for River Management and Design Testing

NASA Astrophysics Data System (ADS)

Lane, B. A. A.; Pasternack, G. B.; Sandoval Solis, S.

2017-12-01

Rivers are highly complex, dynamic systems that support numerous ecosystem functions including transporting sediment, modulating biogeochemical processes, and regulating habitat availability for native species. The extent and timing of these functions is largely controlled by the interplay of hydrologic dynamics (i.e. flow) and the shape and composition of the river corridor (i.e. form). This study applies synthetic channel design to the evaluation of river flow-form-function linkages, with the aim of evaluating these interactions across a range of flows and forms to inform process-driven management efforts with limited data and financial requirements. In an application to California's Mediterranean-montane streams, the interacting roles of channel form, water year type, and hydrologic impairment were evaluated across a suite of ecosystem functions related to hydrogeomorphic processes, aquatic habitat, and riparian habitat. Channel form acted as the dominant control on hydrogeomorphic processes considered, while water year type controlled salmonid habitat functions. Streamflow alteration for hydropower increased redd dewatering risk and altered aquatic habitat availability and riparian recruitment dynamics. Study results highlight critical tradeoffs in ecosystem function performance and emphasize the significance of spatiotemporal diversity of flow and form at multiple scales for maintaining river ecosystem integrity. The approach is broadly applicable and extensible to other systems and ecosystem functions, where findings can be used to characterize complex controls on river ecosystems, assess impacts of proposed flow and form alterations, and inform river restoration strategies.

The Topographic Design of River Channels for Form-Process Linkages.

PubMed

Brown, Rocko A; Pasternack, Gregory B; Lin, Tin

2016-04-01

Scientists and engineers design river topography for a wide variety of uses, such as experimentation, site remediation, dam mitigation, flood management, and river restoration. A recent advancement has been the notion of topographical design to yield specific fluvial mechanisms in conjunction with natural or environmental flow releases. For example, the flow convergence routing mechanism, whereby shear stress and spatially convergent flow migrate or jump from the topographic high (riffle) to the low point (pool) from low to high discharge, is thought to be a key process able to maintain undular relief in gravel bedded rivers. This paper develops an approach to creating riffle-pool topography with a form-process linkage to the flow convergence routing mechanism using an adjustable, quasi equilibrium synthetic channel model. The link from form to process is made through conceptualizing form-process relationships for riffle-pool couplets into geomorphic covariance structures (GCSs) that are then quantitatively embedded in a synthetic channel model. Herein, GCSs were used to parameterize a geometric model to create five straight, synthetic river channels with varying combinations of bed and width undulations. Shear stress and flow direction predictions from 2D hydrodynamic modeling were used to determine if scenarios recreated aspects of the flow convergence routing mechanism. Results show that the creation of riffle-pool couplets that experience flow convergence in straight channels requires GCSs with covarying bed and width undulations in their topography as supported in the literature. This shows that GCSs are a useful way to translate conceptualizations of form-process linkages into quantitative models of channel form.

A nacre protein forms mesoscale hydrogels that “hijack” the biomineralization process within a seawater environment

DOE PAGES

Pendola, Martin; Jain, Gaurav; Davidyants, Anastasia; ...

2016-09-26

We examined the mineralization performance of a nacre protein, AP7, within seawater mineralization assays that form aragonite and magnesium calcite. Under these conditions AP7 forms hydrogel particles that vary in size and complexity depending upon ionic conditions. These hydrogels “hijack” the mineralization process by limiting nucleation in bulk solution and promoting nucleation within the hydrogels.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR FLOW AND CUSTODY OF FIELD DATA FORMS (UA-C-5.0)

EPA Science Inventory

The purpose of this SOP is to describe the flow of field data forms through the data processing system and to define who is responsible for the data at any time. It applies to field data forms collected and processed by Arizona NHEXAS. This procedure was followed to ensure cons...

17 CFR 239.42 - Form F-X, for appointment of agent for service of process and undertaking for issuers registering...

Code of Federal Regulations, 2010 CFR

2010-04-01

..., rights offering or business combination. 239.42 Section 239.42 Commodity and Securities Exchanges... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Form F-X, for appointment of agent for service of process and undertaking for issuers registering securities on Form F-8, F-9, F-10...

PROCESS FOR THE PRODUCTION OF AN ACTIVATED FORM OF UO$sub 2$

DOEpatents

Polissar, M.J.

1957-09-24

A process for producing a highly active form of UO/sub 2/ characterized both by rapid oxidation in air and by rapid chlorination with CCl/sub 4/ vapor at an elevated temperature is reported. In accordance with the process, commercial UO/sub 2/, is subjected to a series of oxidation-reduction operations to produce a form of UC/sub 2/ of enhanced reactivity. By treatimg commercial UO/sub 2/ at a temperature between 335 and 485 deg C with methane, then briefly with an oxygen containing gas and followimg this by a second treatment with a methane containing gas, the original relatively stable charge of UO/sub 2/ will be transformed into an active form of UO/sub 2/.

Investigation of Proposed Process Sequence for the Array Automated Assembly Task, Phase 2. [low cost silicon solar array fabrication

NASA Technical Reports Server (NTRS)

Mardesich, N.; Garcia, A.; Bunyan, S.; Pepe, A.

1979-01-01

The technological readiness of the proposed process sequence was reviewed. Process steps evaluated include: (1) plasma etching to establish a standard surface; (2) forming junctions by diffusion from an N-type polymeric spray-on source; (3) forming a p+ back contact by firing a screen printed aluminum paste; (4) forming screen printed front contacts after cleaning the back aluminum and removing the diffusion oxide; (5) cleaning the junction by a laser scribe operation; (6) forming an antireflection coating by baking a polymeric spray-on film; (7) ultrasonically tin padding the cells; and (8) assembling cell strings into solar circuits using ethylene vinyl acetate as an encapsulant and laminating medium.

Generation kinetics of boron-oxygen complexes in p-type compensated c-Si

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Yichao; Yu, Xuegong, E-mail: yuxuegong@zju.edu.cn; Chen, Peng

2014-03-10

Kinetics characteristics of boron-oxygen complexes responsible for light-induced degradation in p-type compensated c-Si have been investigated. The generation of B-O complexes is well fitted by a fast-forming process and a slow-forming one. Activation energies of complexes generation during the fast-forming process are determined to be 0.29 and 0.24 eV in compensated and non-compensated c-Si, respectively, and those during the slow-forming process are the same, about 0.44 eV. Moreover, it is found that the pre-exponential factors of complexes generation in compensated c-Si is proportional to the square of the net doping concentration, which suggests that the latent centers should exist.

A Rocky Planet Forms

NASA Image and Video Library

2018-01-25

An artist's rendition of how a rocky planet forms. As a rocky planet forms, the planet-forming material gathers in a process known as "accretion." It grows larger in size, and increases in temperature, along with the pressure at its core. The energy from this initial planet forming process causes the planet's elements to heat up and melt. Upon melting, layers form and separate. The heavier elements sink to the bottom, the lighter ones float to the top. This material then separates into layers as it cools, which is known as "differentiation." A fully formed planet slowly emerges, with an upper layer known as the crust, the mantle in the middle, and a solid iron core. InSight is short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. The InSight mission will help answer key questions about how the rocky planets of the solar system, as well as how rocky exoplanets, formed. So while InSight is a Mars mission, it's also more than a Mars mission. The lander seeks the fingerprints of the processes that formed the rocky planets of the solar system, more than 4 billion years ago. It measures the planet's "vital signs:" its "pulse" (seismology), "temperature" (heat flow) and "reflexes" (precision tracking). https://photojournal.jpl.nasa.gov/catalog/PIA22233

Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components

NASA Technical Reports Server (NTRS)

Zimmerman, Frank R.

2004-01-01

The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center, working with the Jet Propulsion Laboratory, has developed and demonstrated a fabrication technique using the VPS process to form anode and cathode sections for a Lorentz force accelerator made from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and deposits the molten metal powder onto a mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions for the inside surface of the anode or cathode of the accelerator. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of Lorentz force accelerator components.

Numerical simulation of multi-layered textile composite reinforcement forming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, P.; Hamila, N.; Boisse, P.

2011-05-04

One important perspective in aeronautics is to produce large, thick or/and complex structural composite parts. The forming stage presents an important role during the whole manufacturing process, especially for LCM processes (Liquid Composites Moulding) or CFRTP (Continuous Fibre Reinforcements and Thermoplastic resin). Numerical simulations corresponding to multi-layered composite forming allow the prediction for a successful process to produce the thick parts, and importantly, the positions of the fibres after forming to be known. This paper details a set of simulation examples carried out by using a semi-discrete shell finite element made up of unit woven cells. The internal virtual workmore » is applied on all woven cells of the element taking into account tensions, in-plane shear and bending effects. As one key problem, the contact behaviours of tool/ply and ply/ply are described in the numerical model. The simulation results not only improve our understanding of the multi-layered composite forming process but also point out the importance of the fibre orientation and inter-ply friction during formability.« less

Transformation through Knowledge--Knowledge through Transformation.

ERIC Educational Resources Information Center

Cadena, Felix

1991-01-01

Defines systematization as the process of creating critical knowledge (conscientization), a form of transformative research. Explains how systematization contributes to popular education and presents the form components of the process: identifying limits of research, obtaining data, interpretation, and socialization. (SK)

Testing single point incremental forming moulds for rotomoulding operations

NASA Astrophysics Data System (ADS)

Afonso, Daniel; de Sousa, Ricardo Alves; Torcato, Ricardo

2017-10-01

Low pressure polymer processes as thermoforming or rotational moulding use much simpler moulds than high pressure processes like injection. However, despite the low forces involved in the process, moulds manufacturing for these applications is still a very material, energy and time consuming operation. Particularly in rotational moulding there is no standard for the mould manufacture and very different techniques are applicable. The goal of this research is to develop and validate a method for manufacturing plastically formed sheet metal moulds by single point incremental forming (SPIF) for rotomoulding and rotocasting operations. A Stewart platform based SPIF machine allow the forming of thick metal sheets, granting the required structural stiffness for the mould surface, and keeping a short manufacture lead time and low thermal inertia. The experimental work involves the proposal of a hollow part, design and fabrication of a sheet metal mould using dieless incremental forming techniques and testing its operation in the production of prototype parts.

When semantics aids phonology: A processing advantage for iconic word forms in aphasia.

PubMed

Meteyard, Lotte; Stoppard, Emily; Snudden, Dee; Cappa, Stefano F; Vigliocco, Gabriella

2015-09-01

Iconicity is the non-arbitrary relation between properties of a phonological form and semantic content (e.g. "moo", "splash"). It is a common feature of both spoken and signed languages, and recent evidence shows that iconic forms confer an advantage during word learning. We explored whether iconic forms conferred a processing advantage for 13 individuals with aphasia following left-hemisphere stroke. Iconic and control words were compared in four different tasks: repetition, reading aloud, auditory lexical decision and visual lexical decision. An advantage for iconic words was seen for some individuals in all tasks, with consistent group effects emerging in reading aloud and auditory lexical decision. Both these tasks rely on mapping between semantics and phonology. We conclude that iconicity aids spoken word processing for individuals with aphasia. This advantage is due to a stronger connection between semantic information and phonological forms. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Use of Explosive Forming for Fastening and Joining Structural and Pressure Components

NASA Technical Reports Server (NTRS)

Schroeder, J. W.

1985-01-01

Explosive expansion of tubes into tubesheets has been used for over 20 years in the fabrication and repair of shell and tube heat exchangers. The use of explosives to perform these expansions has offered several distinct advantages over other methods. First, the process is fast and economical and can be performed with minimal training of personnel. Secondly, explosive forming does not cause the deleterious metallurgical effects which often result from other forming operations. In addition, the process can be performed remotely without the need for sophisticated handling equipment. The expansion of tubes into tubesheets is only one of many possible fastening and joining applications for which explosive forming can be used to achieve highly successful results. The explosive forming process and where it has been used are described. In addition, some possible adaptations to other joining applications are identified and discussed.

Analysis of residual stress state in sheet metal parts processed by single point incremental forming

NASA Astrophysics Data System (ADS)

Maaß, F.; Gies, S.; Dobecki, M.; Brömmelhoff, K.; Tekkaya, A. E.; Reimers, W.

2018-05-01

The mechanical properties of formed metal components are highly affected by the prevailing residual stress state. A selective induction of residual compressive stresses in the component, can improve the product properties such as the fatigue strength. By means of single point incremental forming (SPIF), the residual stress state can be influenced by adjusting the process parameters during the manufacturing process. To achieve a fundamental understanding of the residual stress formation caused by the SPIF process, a valid numerical process model is essential. Within the scope of this paper the significance of kinematic hardening effects on the determined residual stress state is presented based on numerical simulations. The effect of the unclamping step after the manufacturing process is also analyzed. An average deviation of the residual stress amplitudes in the clamped and unclamped condition of 18 % reveals, that the unclamping step needs to be considered to reach a high numerical prediction quality.

The Blurred Line between Form and Process: A Comparison of Stream Channel Classification Frameworks

PubMed Central

Kasprak, Alan; Hough-Snee, Nate

2016-01-01

Stream classification provides a means to understand the diversity and distribution of channels and floodplains that occur across a landscape while identifying links between geomorphic form and process. Accordingly, stream classification is frequently employed as a watershed planning, management, and restoration tool. At the same time, there has been intense debate and criticism of particular frameworks, on the grounds that these frameworks classify stream reaches based largely on their physical form, rather than direct measurements of their component hydrogeomorphic processes. Despite this debate surrounding stream classifications, and their ongoing use in watershed management, direct comparisons of channel classification frameworks are rare. Here we implement four stream classification frameworks and explore the degree to which each make inferences about hydrogeomorphic process from channel form within the Middle Fork John Day Basin, a watershed of high conservation interest within the Columbia River Basin, U.S.A. We compare the results of the River Styles Framework, Natural Channel Classification, Rosgen Classification System, and a channel form-based statistical classification at 33 field-monitored sites. We found that the four frameworks consistently classified reach types into similar groups based on each reach or segment’s dominant hydrogeomorphic elements. Where classified channel types diverged, differences could be attributed to the (a) spatial scale of input data used, (b) the requisite metrics and their order in completing a framework’s decision tree and/or, (c) whether the framework attempts to classify current or historic channel form. Divergence in framework agreement was also observed at reaches where channel planform was decoupled from valley setting. Overall, the relative agreement between frameworks indicates that criticism of individual classifications for their use of form in grouping stream channels may be overstated. These form-based criticisms may also ignore the geomorphic tenet that channel form reflects formative hydrogeomorphic processes across a given landscape. PMID:26982076

Form cues and content difficulty as determinants of children's cognitive processing of televised educational messages.

PubMed

Campbell, T A; Wright, J C; Huston, A C

1987-06-01

An experiment was designed to assess the effects of formal production features and content difficulty on children's processing of televised messages about nutrition. Messages with identical content (the same script and visual shot sequence) were made in two forms: child program forms (animated film, second-person address, and character voice narration with sprightly music) and adult program forms (live photography, third-person address, and adult male narration with sedate background music). For each form, messages were made at three levels of content difficulty. Easier versions were longer, more redundant, and used simpler language; difficult versions presented information more quickly with less redundancy and more abstract language. Regardless of form or difficulty level, each set of bits presented the same basic information. Kindergarten children (N = 120) were assigned to view three different bits of the same form type and difficulty embedded in a miniprogram. Visual attention to child forms was significantly greater than to adult forms; free and cued recall scores were also higher for child than for adult forms. Although all recall and recognition scores were best for easy versions and worst for difficult versions, attention showed only minor variation as a function of content difficulty. Results are interpreted to indicate that formal production features, independently of content, influence the effort and level of processing that children use to understand televised educational messages.

Microstructural and Mechanical Property Characterization of Shear Formed Aerospace Aluminum Alloys

NASA Technical Reports Server (NTRS)

Troeger, Lillianne P.; Domack, Marcia S.; Wagner, John A.

2000-01-01

Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of joints. The current research is an investigation of the processing-microstructure-property relationships for shear formed cylinders of the Al-Cu-Li-Mg-Ag alloy 2195 for space applications and the Al-Cu-Mg-Ag alloy C415 for airframe applications. Cylinders which had undergone various amounts of shear-forming strain were studied to correlate the grain structure, texture, and mechanical properties developed during and after shear forming.

Microstructural and Mechanical Characterization of Shear Formed Aluminum Alloys for Airframe and Space Applications

NASA Technical Reports Server (NTRS)

Troeger, L. P.; Domack, M. S.; Wagner, J. A.

1998-01-01

Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of joints. The current research is an investigation of the processing-microstructure-property relationship for shear formed cylinders of the Al-Cu-Li-Mg-Ag alloy 2195 for space applications and the Al-Cu-Mg-Ag alloy C415 for airframe applications. Cylinders which have undergone various amounts of shear-forming strain have been studied to assess the microstructure and mechanical properties developed during and after shear forming.

20 CFR 10.915 - What are the responsibilities of OWCP in the death gratuity payment process?

Code of Federal Regulations, 2013 CFR

2013-04-01

... responsibilities of OWCP in the death gratuity payment process? (a) If the death gratuity payment process is initiated by the employing agency's submission of form CA-42, OWCP will identify living potential claimants. OWCP will make a reasonable effort to provide claim form CA-41s to any known potential claimants and...

20 CFR 10.915 - What are the responsibilities of OWCP in the death gratuity payment process?

Code of Federal Regulations, 2014 CFR

2014-04-01

... responsibilities of OWCP in the death gratuity payment process? (a) If the death gratuity payment process is initiated by the employing agency's submission of form CA-42, OWCP will identify living potential claimants. OWCP will make a reasonable effort to provide claim form CA-41s to any known potential claimants and...

20 CFR 10.915 - What are the responsibilities of OWCP in the death gratuity payment process?

Code of Federal Regulations, 2011 CFR

2011-04-01

... responsibilities of OWCP in the death gratuity payment process? (a) If the death gratuity payment process is initiated by the employing agency's submission of form CA-42, OWCP will identify living potential claimants. OWCP will make a reasonable effort to provide claim form CA-41's to any known potential claimants and...

20 CFR 10.915 - What are the responsibilities of OWCP in the death gratuity payment process?

Code of Federal Regulations, 2010 CFR

2010-04-01

... responsibilities of OWCP in the death gratuity payment process? (a) If the death gratuity payment process is initiated by the employing agency's submission of form CA-42, OWCP will identify living potential claimants. OWCP will make a reasonable effort to provide claim form CA-41's to any known potential claimants and...

20 CFR 10.915 - What are the responsibilities of OWCP in the death gratuity payment process?

Code of Federal Regulations, 2012 CFR

2012-04-01

... responsibilities of OWCP in the death gratuity payment process? (a) If the death gratuity payment process is initiated by the employing agency's submission of form CA-42, OWCP will identify living potential claimants. OWCP will make a reasonable effort to provide claim form CA-41s to any known potential claimants and...

The Roles of Structured Input Activities in Processing Instruction and the Kinds of Knowledge They Promote

ERIC Educational Resources Information Center

Marsden, Emma; Chen, Hsin-Ying

2011-01-01

This study aimed to isolate the effects of the two input activities in Processing Instruction: referential activities, which force learners to focus on a form and its meaning, and affective activities, which contain exemplars of the target form and require learners to process sentence meaning. One hundred and twenty 12-year-old Taiwanese learners…

Process and apparatus for the production of BI-213 cations

DOEpatents

Horwitz, E. Philip; Hines, John J.; Chiarizia, Renato; Dietz, Mark

1998-01-01

A process for producing substantially impurity-free Bi-213 cations is disclosed. An aqueous acid feed solution containing Ac-225 cations is contacted with an ion exchange medium to bind the Ac-225 cations and form an Ac-225-laden ion exchange medium. The bound Ac-225 incubates on the ion exchange medium to form Bi-213 cations by radioactive decay. The Bi-213 cations are then recovered from the Ac-225-laden ion exchange medium to form a substantially impurity-free aqueous Bi-213 cation acid solution. An apparatus for carrying out this process is also disclosed.

Composition and process for the encapsulation and stabilization of radioactive hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1997-07-15

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a ``clean`` polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1998-03-24

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a ``clean`` polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Composition and process for the encapsulation and stabilization of radioactive, hazardous and mixed wastes

DOEpatents

Kalb, P.D.; Colombo, P.

1999-07-20

The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogeneous molten matrix. The molten matrix may be directed in a clean'' polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment. 2 figs.

Hot forming of composite prepreg: Numerical analyses

NASA Astrophysics Data System (ADS)

Guzman-Maldonado, Eduardo; Hamila, Nahiène; Boisse, Philippe; El Azzouzi, Khalid; Tardif, Xavier; Moro, Tanguy; Chatel, Sylvain; Fideu, Paulin

2017-10-01

The work presented here is part of the "FORBANS" project about the Hot Drape Forming (HDF) process consisting of unidirectional prepregs laminates. To ensure a fine comprehension of this process a combination strategy between experiment and numerical analysis is adopted. This paper is focused on the numerical analysis using the finite element method (FEM) with a hyperelastic constitutive law. Each prepreg layer is modelled by shell elements. These elements consider the tension, in-plane shear and bending behaviour of the ply at different temperatures. The contact/friction during the forming process is taken into account using forward increment Lagrange multipliers.

Process and apparatus for the production of Bi-213 cations

DOEpatents

Horwitz, E.P.; Hines, J.J.; Chiarizia, R.; Dietz, M.

1998-12-29

A process for producing substantially impurity-free Bi-213 cations is disclosed. An aqueous acid feed solution containing Ac-225 cations is contacted with an ion exchange medium to bind the Ac-225 cations and form an Ac-225-laden ion exchange medium. The bound Ac-225 incubates on the ion exchange medium to form Bi-213 cations by radioactive decay. The Bi-213 cations are then recovered from the Ac-225-laden ion exchange medium to form a substantially impurity-free aqueous Bi-213 cation acid solution. An apparatus for carrying out this process is also disclosed. 7 figs.

Convergence to Diagonal Form of Block Jacobi-type Processes

NASA Astrophysics Data System (ADS)

Hari, Vjeran

2008-09-01

The main result of recent research on convergence to diagonal form of block Jacobi-type processes is presented. For this purpose, all notions needed to describe the result are introduced. In particular, elementary block transformation matrices, simple and non-simple algorithms, block pivot strategies together with the appropriate equivalence relations are defined. The general block Jacobi-type process considered here can be specialized to take the form of almost any known Jacobi-type method for solving the ordinary or the generalized matrix eigenvalue and singular value problems. The assumptions used in the result are satisfied by many concrete methods.

The impact of recreational MDMA 'ecstasy' use on global form processing.

PubMed

White, Claire; Edwards, Mark; Brown, John; Bell, Jason

2014-11-01

The ability to integrate local orientation information into a global form percept was investigated in long-term ecstasy users. Evidence suggests that ecstasy disrupts the serotonin system, with the visual areas of the brain being particularly susceptible. Previous research has found altered orientation processing in the primary visual area (V1) of users, thought to be due to disrupted serotonin-mediated lateral inhibition. The current study aimed to investigate whether orientation deficits extend to higher visual areas involved in global form processing. Forty-five participants completed a psychophysical (Glass pattern) study allowing an investigation into the mechanisms underlying global form processing and sensitivity to changes in the offset of the stimuli (jitter). A subgroup of polydrug-ecstasy users (n=6) with high ecstasy use had significantly higher thresholds for the detection of Glass patterns than controls (n=21, p=0.039) after Bonferroni correction. There was also a significant interaction between jitter level and drug-group, with polydrug-ecstasy users showing reduced sensitivity to alterations in jitter level (p=0.003). These results extend previous research, suggesting disrupted global form processing and reduced sensitivity to orientation jitter with ecstasy use. Further research is needed to investigate this finding in a larger sample of heavy ecstasy users and to differentiate the effects of other drugs. © The Author(s) 2014.

[Formation and persistence of L-variants of Salmonella typhi in experimental typhoid and in carriers].

PubMed

Levina, G A; Prozorovskiĭ, S V; Iagud, S L; Grumman, M I; Gorelov, A L

1981-07-01

The possibility of the induction and persistence of S. typhi L-forms in the process of experimental typhoid infection and carriership has been studied in rabbits. This study has revealed that the process of L-transformation leading to the appearance of the imbalanced growth forms and unstable L-forms of S. typhi in the organism of the animals infected with S. typhi culture may occur under the conditions of carriership. Such changed forms can be detected in the organism of the animals 18 months after the primary infection.

Treatment of mercury containing waste

DOEpatents

Kalb, Paul D.; Melamed, Dan; Patel, Bhavesh R; Fuhrmann, Mark

2002-01-01

A process is provided for the treatment of mercury containing waste in a single reaction vessel which includes a) stabilizing the waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture and b) encapsulating the resulting mixture by heating the mixture to form a molten product and casting the molten product as a monolithic final waste form. Additional sulfur polymer cement can be added in the encapsulation step if needed, and a stabilizing additive can be added in the process to improve the leaching properties of the waste form.

The competition between the liquid-liquid dewetting and the liquid-solid dewetting.

PubMed

Xu, Lin; Shi, Tongfei; An, Lijia

2009-05-14

We investigate the dewetting behavior of the bilayer of air/PS/PMMA/silanized Si wafer and find the two competing dewetting pathways in the dewetting process. The upper layer dewets on the lower layer (dewetting pathway 1, the liquid-liquid dewetting) and the two layers rupture on the solid substrate (dewetting pathway 2, the liquid-solid dewetting). To the two competing dewetting pathways, the process of forming holes and the process of hole growth, influence their competing relation. In the process of forming holes, the time of forming holes is a main factor that influences their competing relation. During the process of hole growth, the dewetting velocity is a main factor that influences their competing relation. The liquid-liquid interfacial tension, the film thickness of the polymer, and the viscosity of the polymer are important factors that influence the time of forming holes and the dewetting velocity. When the liquid-liquid dewetting pathway and the liquid-solid dewetting pathway compete in the dewetting process, the competing relation can be controlled by changing the molecular weight of the polymer, the film thickness, and the annealing temperature. In addition, it is also found that the rim growth on the solid substrate is by a rolling mechanism in the process of hole growth.

Metal-doped organic gels and method thereof

DOEpatents

Satcher, Jr., Joe H.; Baumann, Theodore F.

2003-09-02

Disclosed herein is a sol-gel polymerization process for synthesizing metal-doped organic gels. The process polymerizes metal salts of hydroxylated benzenes or hydroxylated benzene derivatives with alkyl or aryl aldehydes to form metal-doped, wet, organic gels. The gels can then be dried by supercritical solvent extraction to form metal-doped aerogels or by evaporation to form metal-doped xerogels. The aerogels and xerogels can then be pyrolyzed.

AFLCMC Cd and Cr Replacement/Elimination Strategy

DTIC Science & Technology

2014-11-18

Dominant Air Power: Design For Tomorrow…Deliver Today Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Product...Airworthiness Process for Deploying New or Substitute Materials, Processes, and Product Forms 2 Abatement Costs • In Nov 2012, SECAF directed the AF find

32 CFR Appendix C to Part 286 - DD Form 2086, “Record of Freedom of Information (FOI) Processing Cost”

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 2 2010-07-01 2010-07-01 false DD Form 2086, âRecord of Freedom of Information (FOI) Processing Costâ C Appendix C to Part 286 National Defense Department of Defense (Continued... INFORMATION ACT PROGRAM REGULATION Pt. 286, App. C Appendix C to Part 286—DD Form 2086, “Record of Freedom of...

Metal-doped organic gels and method thereof

DOEpatents

Satcher, Jr., Joe H.; Baumann, Theodore F.

2007-10-23

Disclosed herein is a sol-gel polymerization process for synthesizing metal-doped organic gels. The process polymerizes metal salts of hydroxylated benzenes or hydroxylated benzene derivatives with alkyl or aryl aldehydes to form metal-doped, wet, organic gels. The gels can then be dried by supercritical solvent extraction to form metal-doped aerogels or by evaporation to form metal-doped xerogels. The aerogels and xerogels can then be pyrolyzed.

Fundamental Research on Heat Transfer Characteristics in Shell & Tube Type Ice Forming Cold Energy Storage

NASA Astrophysics Data System (ADS)

Saito, Akio; Utaka, Yoshio; Okawa, Seiji; Ishibashi, Hiroaki

Investigation of heat transfer characteristics in an ice making cold energy storage using a set of horizontal cooling pipes was carried out experimentally. Cooling pipe arrangement, number of pipes used and initial water temperature were varied, and temperature distribution in the tank and the volume of ice formed around the pipe were measured. Natural convection was also observed visually. During the experiment, two kinds of layers were observed. One is the layer where ice forming is interfered by natural convection and its temperature decreases rapidly with an almost uniform temperature distribution, and the other is the layer where ice forms steadily under a stagnant water condition. The former was called that the layer is under a cooling process and the latter that the layer is under an ice forming process. The effect of the experimental parameters, such as the arrangement of the cooling pipes, the number of pipes, the initial water temperature and the flow rate of the cooling medium, on the cooling process and the ice forming process were discussed. Approximate analysis was also carried out and compared with the experimental results. Finally, the relationship between the ice packing factor, which is significant in preventing the blockade, and experimental parameters was discussed.

Integrative cortical dysfunction and pervasive motion perception deficit in fragile X syndrome.

PubMed

Kogan, C S; Bertone, A; Cornish, K; Boutet, I; Der Kaloustian, V M; Andermann, E; Faubert, J; Chaudhuri, A

2004-11-09

Fragile X syndrome (FXS) is associated with neurologic deficits recently attributed to the magnocellular pathway of the lateral geniculate nucleus. To test the hypotheses that FXS individuals 1) have a pervasive visual motion perception impairment affecting neocortical circuits in the parietal lobe and 2) have deficits in integrative neocortical mechanisms necessary for perception of complex stimuli. Psychophysical tests of visual motion and form perception defined by either first-order (luminance) or second-order (texture) attributes were used to probe early and later occipito-temporal and occipito-parietal functioning. When compared to developmental- and age-matched controls, FXS individuals displayed severe impairments in first- and second-order motion perception. This deficit was accompanied by near normal perception for first-order form stimuli but not second-order form stimuli. Impaired visual motion processing for first- and second-order stimuli suggests that both early- and later-level neurologic function of the parietal lobe are affected in Fragile X syndrome (FXS). Furthermore, this deficit likely stems from abnormal input from the magnocellular compartment of the lateral geniculate nucleus. Impaired visual form and motion processing for complex visual stimuli with normal processing for simple (i.e., first-order) form stimuli suggests that FXS individuals have normal early form processing accompanied by a generalized impairment in neurologic mechanisms necessary for integrating all early visual input.

A novel proteolytic processing of prolysyl oxidase

PubMed Central

Atsawasuwan, Phimon; Mochida, Yoshiyuki; Katafuchi, Michitsuna; Tokutomi, Kentaro; Mocanu, Viorel; Parker, Carol E.; Yamauchi, Mitsuo

2012-01-01

Lysyl oxidase (LOX) is an amine oxidase that is critical for the stability of connective tissues. The secreted proLOX is enzymatically quiescent and is activated through proteolytic cleavage between residue Gly162 and Asp163 (residue numbers according to the mouse LOX) by bone morphogenetic protein (BMP)-1 gene products. Here we report a novel processing of proLOX identified in vitro and in vivo. Two forms of mature LOX were identified and characterized by their immunoreactivity to specific antibodies, amine oxidase activity and mass spectrometry. One form was identified as a well characterized BMP-1 processed LOX protein. Another was found to be a truncated form of LOX (tLOX) resulting from the cleavage at the carboxy terminus of Arg192. The tLOX still appeared to retain amine oxidase activity. The results from the proLOX gene deletion and mutation experiments indicated that the processing occurs independent of the cleavage of proLOX by BMP-1 gene products and likely requires the presence of LOX propeptide. These results indicate that proLOX could be processed by two different mechanisms producing two forms of active LOX. PMID:21591931

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiebenga, J. H.; Atzema, E. H.; Boogaard, A. H. van den

Robust design of forming processes using numerical simulations is gaining attention throughout the industry. In this work, it is demonstrated how robust optimization can assist in further stretching the limits of metal forming processes. A deterministic and a robust optimization study are performed, considering a stretch-drawing process of a hemispherical cup product. For the robust optimization study, both the effect of material and process scatter are taken into account. For quantifying the material scatter, samples of 41 coils of a drawing quality forming steel have been collected. The stochastic material behavior is obtained by a hybrid approach, combining mechanical testingmore » and texture analysis, and efficiently implemented in a metamodel based optimization strategy. The deterministic and robust optimization results are subsequently presented and compared, demonstrating an increased process robustness and decreased number of product rejects by application of the robust optimization approach.« less

Process for producing furan from furfural aldehyde

DOEpatents

Diebold, James P.; Evans, Robert J.

1988-01-01

A process of producing furan and derivatives thereof is disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

Process for producing furan from furfural aldehyde

DOEpatents

Diebold, J.P.; Evans, R.J.

1987-04-06

A process of producing furan and derivatives thereof as disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

Assessment of DoD Enterprise Resource Planning Business Systems

DTIC Science & Technology

2011-02-01

activities, and processes to the organizational units that execute them • Architecture standards, such as application of the BPMN • Recommended...Recommendation: • Create and use style guides for the development of BPMN based process models. The style guide would probably include specifications such as...o All processes must have ‘entry points’ or ‘triggers’ in the form of BPMN Events o All processes must have ‘outcomes’ also in the form of BPMN

Visual form-processing deficits: a global clinical classification.

PubMed

Unzueta-Arce, J; García-García, R; Ladera-Fernández, V; Perea-Bartolomé, M V; Mora-Simón, S; Cacho-Gutiérrez, J

2014-10-01

Patients who have difficulties recognising visual form stimuli are usually labelled as having visual agnosia. However, recent studies let us identify different clinical manifestations corresponding to discrete diagnostic entities which reflect a variety of deficits along the continuum of cortical visual processing. We reviewed different clinical cases published in medical literature as well as proposals for classifying deficits in order to provide a global perspective of the subject. Here, we present the main findings on the neuroanatomical basis of visual form processing and discuss the criteria for evaluating processing which may be abnormal. We also include an inclusive diagram of visual form processing deficits which represents the different clinical cases described in the literature. Lastly, we propose a boosted decision tree to serve as a guide in the process of diagnosing such cases. Although the medical community largely agrees on which cortical areas and neuronal circuits are involved in visual processing, future studies making use of new functional neuroimaging techniques will provide more in-depth information. A well-structured and exhaustive assessment of the different stages of visual processing, designed with a global view of the deficit in mind, will give a better idea of the prognosis and serve as a basis for planning personalised psychostimulation and rehabilitation strategies. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Leishmania mexicana differentiation involves a selective plasma membrane autophagic-like process.

PubMed

Dagger, Francehuli; Bengio, Camila; Martinez, Angel; Ayesta, Carlos

2017-11-23

Parasites of the Leishmania genus, which are the causative agents of leishmaniasis, display a complex life cycle, from a flagellated form (promastigotes) residing in the midgut of the phlebotomine vector to a non-flagellated form (amastigote) invading the mammalian host. The cellular process for the conversion between these forms is an interesting biological phenomenon involving modulation of the plasma membrane. In this study, we describe a selective autophagic-like process during the in vitro differentiation of Leishmania mexicana promastigote to amastigote-like cells. This process is responsible for size reduction and shape change of the promastigote (15-20 μm long) to the rounded amastigote-like form (4-5 μm long), identical to the one that infects host macrophages. This autophagic-like process is characterized by a profound folding of the plasma membrane and the presence of abundant cytoplasmic lipid droplets that may be the product of changes in the lipid metabolism. The key feature for the differentiation process at either pH 7.0 or pH 5.5 is the shift in temperature from 25 to 35 °C. Flagella shortening during the differentiation process appears as the product of continuous flagellar microtubular disassembly that is also accompanied by changes in mitochondrion localization. Drugs directed at blocking the parasite autophagic-like process could be important as new strategies to fight the disease.

Leveraging Health Information Exchange to Improve Population Health Reporting Processes: Lessons in Using a Collaborative-Participatory Design Process

PubMed Central

Revere, Debra; Dixon, Brian E.; Hills, Rebecca; Williams, Jennifer L.; Grannis, Shaun J.

2014-01-01

Introduction: Surveillance, or the systematic monitoring of disease within a population, is a cornerstone function of public health. Despite significant investment in information technologies (IT) to improve the public’s health, health care providers continue to rely on manual, spontaneous reporting processes that can result in incomplete and delayed surveillance activities. Background: Participatory design principles advocate including real users and stakeholders when designing an information system to ensure high ecological validity of the product, incorporate relevance and context into the design, reduce misconceptions designers can make due to insufficient domain expertise, and ultimately reduce barriers to adoption of the system. This paper focuses on the collaborative and informal participatory design process used to develop enhanced, IT-enabled reporting processes that leverage available electronic health records in a health information exchange to prepopulate notifiable-conditions report forms used by public health authorities. Methods: Over nine months, public health stakeholders, technical staff, and informatics researchers were engaged in a multiphase participatory design process that included public health stakeholder focus groups, investigator-engineering team meetings, public health survey and census regarding high-priority data elements, and codesign of exploratory prototypes and final form mock-ups. Findings: A number of state-mandated report fields that are not highly used or desirable for disease investigation were eliminated, which allowed engineers to repurpose form space for desired and high-priority data elements and improve the usability of the forms. Our participatory design process ensured that IT development was driven by end user expertise and needs, resulting in significant improvements to the layout and functionality of the reporting forms. Discussion: In addition to informing report form development, engaging with public health end users and stakeholders through the participatory design process provided new insights into public health workflow and allowed the team to quickly triage user requests while managing user expectations within the realm of engineering possibilities. Conclusion: Engaging public health, engineering staff, and investigators in a shared codesigning process ensured that the new forms will not only meet real-life needs but will also support development of a product that will be adopted and, ultimately, improve communicable and infectious disease reporting by clinicians to public health. PMID:25848615

Batch fabrication process development for ferrite logic conductors

NASA Technical Reports Server (NTRS)

Heckler, C. H., Jr.; Bhiwandker, N. C.

1972-01-01

A process for fabricating ultrareliable magnetic ferrite logic circuits is described in which the conductors are formed by a combination of two batch type processes - photolithography and electroplating - and a mechanized writing process for completing conductors in the third dimension. Up to 4 turns, through an aperture 1 mm in diameter, are formed by the described process. The number of joints in the conductors is reduced by use of this process to only those which are required for input, output and power connections of a logic block. To demonstrate feasibility, 8-stage magnetic ring counter circuits have been fabricated.

Processing of metacaspase 2 from Trypanosoma brucei (TbMCA2) broadens its substrate specificity.

PubMed

Gilio, Joyce M; Marcondes, Marcelo F; Ferrari, Débora; Juliano, Maria A; Juliano, Luiz; Oliveira, Vitor; Machado, Maurício F M

2017-04-01

Metacaspases are members of the cysteine peptidase family and may be implicated in programmed cell death in plants and lower eukaryotes. These proteases exhibit calcium-dependent activity and specificity for arginine residues at P 1 . In contrast to caspases, they do not require processing or dimerization for activity. Indeed, unprocessed metacaspase-2 of Trypanosoma brucei (TbMCA2) is active; however, it has been shown that cleavages at Lys 55 and Lys 268 increase TbMCA2 hydrolytic activity on synthetic substrates. The processed TbMCA2 comprises 3 polypeptide chains that remain attached by non-covalent bonds. Replacement of Lys 55 and Lys 268 with Gly via site-directed mutagenesis results in non-processed but enzymatically active mutant, TbMCA2 K55/268G. To investigate the importance of this processing for the activity and specificity of TbMCA2, we performed activity assays comparing the non-processed mutant (TbMCA2 K55/268G) with the processed TbMCA2 form. Significant differences between TbMCA2 WT (processed form) and TbMCA2 K55/268G (non-processed form) were observed. Specifically, we verified that although non-processed TbMCA2 is active when assayed with small synthetic substrates, the TbMCA2 form does not exhibit hydrolytic activity on large substrates such as azocasein, while processed TbMCA2 is able to readily digest this protein. Such differences can be relevant for understanding the physiological regulation and function of TbMCA2. Copyright © 2017 Elsevier B.V. All rights reserved.

19 CFR 142.11 - Entry summary form.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Entry summary form. 142.11 Section 142.11 Customs... (CONTINUED) ENTRY PROCESS Entry Summary Documentation § 142.11 Entry summary form. (a) Customs Form 7501. The entry summary shall be on Customs Form 7501 unless a different form is prescribed elsewhere in this...

Comparative risk assessments for the production and interim storage of glass and ceramic waste forms: Defense waste processing facility

NASA Astrophysics Data System (ADS)

Huang, J. C.; Wright, W. V.

1982-04-01

The Defense Waste Processing Facility (DWPF) for immobilizing nuclear high level waste (HLW) is scheduled to be built. High level waste is produced when reactor components are subjected to chemical separation operations. Two candidates for immobilizing this HLW are borosilicate glass and crystalline ceramic, either being contained in weld sealed stainless steel canisters. A number of technical analyses are being conducted to support a selection between these two waste forms. The risks associated with the manufacture and interim storage of these two forms in the DWPF are compared. Process information used in the risk analysis was taken primarily from a DWPF processibility analysis. The DWPF environmental analysis provided much of the necessary environmental information.

Dislocation creep accommodated Grain Boundary Sliding: A high strain rate/low temperature deformation mechanism in calcite ultramylonites

NASA Astrophysics Data System (ADS)

Rogowitz, Anna; Grasemann, Bernhard

2014-05-01

Grain boundary sliding (GBS) is an important grain size sensitive deformation mechanism that is often associated with extreme strain localization and superplasticity. Another mechanism has to operate simultaneously to GBS in order to prevent overlaps and voids between sliding grains. One of the most common accommodating mechanisms is diffusional creep but, recently, dislocation creep has been reported to operate simultaneous to GBS. Due to the formation of a flanking structure in nearly pure calcite marble on Syros (Cyclades, Greece) at lower greenschist facies conditions, an extremely fine grained ultramylonite developed. The microstructure of the layer is characterized by (1) calcite grains with an average grain size of 3.6 µm (developed by low temperature/high strain rate grain boundary migration recrystallization, BLG), (2) grain boundary triple junctions with nearly 120° angles and (3) small cavities preferentially located at triple junctions and at grain boundaries in extension. These features suggest that the dominant deformation mechanism was GBS. In order to get more information on the accommodation mechanism detailed microstructural and textural analyses have been performed on a FEI Quanta 3D FEG instrument equipped with an EDAX Digiview IV EBSD camera. The misorientation distribution curves for correlated and uncorrelated grains follow almost perfect the calculated theoretical curve for a random distribution, which is typical for polycrystalline material deformed by GBS. However, the crystallographic preferred orientation indicates that dislocation creep might have operated simultaneously. We also report Zener-Stroh cracks resulting from dislocation pile up, indicating that dislocation movement was active. We, therefore, conclude that the dominant deformation mechanism was dislocation creep accommodated grain boundary sliding. This is consistent with the observed grain size range that plots at the field boundary between grain size insensitive and grain size sensitive creep, in a deformation mechanism map for calcite.

Can grain size sensitive flow lubricate faults during the initial stages of earthquake propagation?

NASA Astrophysics Data System (ADS)

De Paola, Nicola; Holdsworth, Robert E.; Viti, Cecilia; Collettini, Cristiano; Bullock, Rachael

2015-12-01

Recent friction experiments carried out under upper crustal P-T conditions have shown that microstructures typical of high temperature creep develop in the slip zone of experimental faults. These mechanisms are more commonly thought to control aseismic viscous flow and shear zone strength in the lower crust/upper mantle. In this study, displacement-controlled experiments have been performed on carbonate gouges at seismic slip rates (1 m s-1), to investigate whether they may also control the frictional strength of seismic faults at the higher strain rates attained in the brittle crust. At relatively low displacements (<1 cm) and temperatures (≤100 °C), brittle fracturing and cataclasis produce shear localisation and grain size reduction in a thin slip zone (150 μm). With increasing displacement (up to 15 cm) and temperatures (T up to 600 °C), due to frictional heating, intracrystalline plasticity mechanisms start to accommodate intragranular strain in the slip zone, and play a key role in producing nanoscale subgrains (≤100 nm). With further displacement and temperature rise, the onset of weakening coincides with the formation in the slip zone of equiaxial, nanograin aggregates exhibiting polygonal grain boundaries, no shape or crystal preferred orientation and low dislocation densities, possibly due to high temperature (>900 °C) grain boundary sliding (GBS) deformation mechanisms. The observed micro-textures are strikingly similar to those predicted by theoretical studies, and those observed during experiments on metals and fine-grained carbonates, where superplastic behaviour has been inferred. To a first approximation, the measured drop in strength is in agreement with our flow stress calculations, suggesting that strain could be accommodated more efficiently by these mechanisms within the weaker bulk slip zone, rather than by frictional sliding along the main slip surfaces in the slip zone. Frictionally induced, grainsize-sensitive GBS deformation mechanisms can thus account for the self-lubrication and dynamic weakening of carbonate faults during earthquake propagation in nature.

A novel approach for preparation and in situ tensile testing of silica glass membranes in the TEM

NASA Astrophysics Data System (ADS)

Mačković, Mirza; Przybilla, Thomas; Dieker, Christel; Herre, Patrick; Romeis, Stefan; Stara, Hana; Schrenker, Nadine; Peukert, Wolfgang; Spiecker, Erdmann

2017-04-01

The mechanical behavior of glasses in the micro- and/or nanometer regime increasingly gains importance in nowadays modern technology. However, suitable small scale preparation and mechanical testing approaches for a reliable assessment of the mechanical properties of glasses still remain a big challenge. In the present work, a novel approach for site-specific preparation and quantitative in situ tensile testing of thin silica glass membranes in the transmission electron microscope is presented. Thereby, advanced focused ion beam techniques are used for the preparation of nanoscale dog bone shaped silica glass specimens suitable for in situ tensile testing. Small amounts of gallium are detected on the surface of the membranes resulting from redeposition effects during the focused ion beam preparation procedure. Possible structural changes of silica glass upon irradiation with electrons and gallium ions are investigated by controlled irradiation experiments, followed by a structural analysis using Raman spectroscopy. While moderate electron beam irradiation does not alter the structure of silica glass, ion beam irradiation results in minor densification of the silica glass membranes. In situ tensile testing of membranes under electron beam irradiation results in distinctive elongations without fracture confirming the phenomenon of superplasticity. In contrast, in situ tensile testing in the absence of the electron beam reveals an elastic/plastic deformation behavior, and finally leads to fracture of the membranes. The Young’s moduli of the glass membranes pulled at beam off conditions in the TEM are comparable with values known for bulk fused silica, while the tensile strength is in the range of values reported for silica glass fibers with comparable dimensions. The impact of electron beam irradiation on the mechanical properties of silica glass membranes is further discussed. The results of the present work open new avenues for dedicated preparation and nanomechanical characterization of silica glasses, and further contribute to a fundamental understanding of the mechanical behavior of such glasses when being scaled down to the nanometer regime.