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Sample records for isostatically pressed beryllium-aluminum-silver

  1. Hot isostatic pressing of ceramics

    NASA Technical Reports Server (NTRS)

    Honma, K.

    1985-01-01

    A mixture containing glass 70 to 95 and BN or B4C powder (0.1-10 microns) 5 to 30 vol. % is used as a secondary pressure medium in hot isostatic pressing of ceramics. Thus, Pyrex beads were mixed with 15% vol. BN powder (average diameter 2 microns), fused at 1400 deg for 2 h, cooled, crushed, and put into a graphite crucible. A Si3N4 sintered body was embedded in the powder, heated in vacuum at 1200 deg for 2 h, treated in a hot isostatic press furnace at 1700 deg and 1000 atm. for 1 h, and cooled to give a Si3N4 ceramic. It was easily separated from the crucible.

  2. METHOD FOR SOLVENT-ISOSTATIC PRESSING

    DOEpatents

    Archibald, P.B.

    1962-09-18

    This invention provides a method for producing densely compacted bodies having relatively large dimensions. The method comprises the addition of a small quantity of a suitable solvent to a powder which is to be compacted. The solvent- moistened powder is placed inside a flexible bag, and the bag is suspended in an isostatic press. The solvent is squeezed out of the powder by the isostatic pressure, and the resulting compacted body is recovered. The presence of the solvent markedly decreases the proportion of void space in the powder, thereby resulting in a denser, more homogeneous compact. Another effect of the solvent is that it allows the isostatic pressing operation to be conducted at substantially lower pressures than are conventionally employed. (AEC)

  3. Hot Isostatic Pressing of 60-Nitinol

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2015-01-01

    The effects of varying the time, temperature and pressure during consolidation of 60-Nitinol (Nickel Titanium alloy) by hot isostatic pressing (HIP) were examined. Six HIP cycles with a cycle time of either 2 or 20 hours, temperature of 900 or 1000 degrees Centigrade, and a chamber pressure of either 100 or 200 millipascals were used. The cycle representing the shortest cycle time at the highest temperature and pressure (2 hours/1000 degrees Centigrade/200 millipascals) produced material with the highest hardness (720 Vickers Pyramid Number (HV)). A modest increase in average grain size and significant porosity reduction were observed in material subjected to the longest cycle time at the highest temperature, regardless of the pressure applied. The intent of this study is to facilitate the technology transfer involved in the processing of this material.

  4. Hot isostatic press waste option study report

    SciTech Connect

    Russell, N.E.; Taylor, D.D.

    1998-02-01

    A Settlement Agreement between the Department of Energy and the State of Idaho mandates that all high-level radioactive waste now stored at the Idaho Chemical Processing Plant be treated so that it is ready to move out of Idaho for disposal by the target date of 2035. This study investigates the immobilization of all Idaho Chemical Processing Plant calcine, including calcined sodium bearing waste, via the process known as hot isostatic press, which produces compact solid waste forms by means of high temperature and pressure (1,050 C and 20,000 psi), as the treatment method for complying with the settlement agreement. The final waste product would be contained in stainless-steel canisters, the same type used at the Savannah River Site for vitrified waste, and stored at the Idaho National Engineering and Environmental Laboratory until a national geological repository becomes available for its disposal. The waste processing period is from 2013 through 2032, and disposal at the High Level Waste repository will probably begin sometime after 2065.

  5. Joining of ceramics of different biofunction by hot isostatic pressing

    SciTech Connect

    Li, Jianguo . Center for Dental Technology and Biomaterials); Harmansson, L. ); Soeremark, R. . Dept. of Prosthodontics)

    1993-10-01

    Monolithic zirconia (Z) and zirconia-hydroxyapatite (Z/HA) composites were joined by cold isostatic pressing (CIP at 300 MPa) and subsequently by glass-encapsulated hot isostatic pressing (HIP at 1225 C, 1 h and 200 MPa). The physical and mechanical properties of the materials were measured. The fracture surface was studied using a light microscope. The results indicate a strength level of the joint similar to that of the corresponding composite material (Z/HA), 845 and 860 MPa, respectively. Similar experiments with monolithic alumina (A) and alumina-hydroxyapatite (A/HA) were carried out without success. Cracking occurred in the joint area during the cold isostatic pressing process. It seems that ceramics with high green strength and similar green density are essential when joining ceramics by combined CIP and HIP processes.

  6. Hot Isostatic Press (HIP) vitrification of radwaste concretes

    SciTech Connect

    Siemer, D.D.; Scheetz, B.; Gougar, M.L.D.

    1995-12-01

    Properly formulated and properly ``canned`` radwaste concretes can be readily hot-isostatically-pressed (HIPed) into materials that exhibit performance equivalent to typical radwaste-type glasses. The HIPing conditions (temperature/pressure) required to turn a concrete waste form into a ``vitrified`` waste form are quite mild and therefore consistent with both safety and high productivity. This paper describes the process and its products with reference to its potential application to Idaho Chemical Processing Plant (ICPP) reprocessing wastes.

  7. Fabrication of Monolithic RERTR Fuels by Hot Isostatic Pressing

    SciTech Connect

    Jan-Fong Jue; Blair H. Park; Curtis R. Clark; Glenn A. Moore; Dennis D. Keiser, Jr.

    2010-11-01

    The RERTR (Reduced Enrichment for Research and Test Reactors) Program is developing advanced nuclear fuels for high-power test reactors. Monolithic fuel design provides higher uranium loading than that of the traditional dispersion fuel design. Hot isostatic pressing is a promising process for low-cost batch fabrication of monolithic RERTR fuel plates for these high-power reactors. Bonding U Mo fuel foil and 6061 Al cladding by hot isostatic press bonding was successfully developed at Idaho National Laboratory. Due to the relatively high processing temperature, the interaction between fuel meat and aluminum cladding is a concern. Two different methods were employed to mitigate this effect: (1) a diffusion barrier and (2) a doping addition to the interface. Both types of fuel plates have been fabricated by hot isostatic press bonding. Preliminary results show that the direct fuel/cladding interaction during the bonding process was eliminated by introducing a thin zirconium diffusion barrier layer between the fuel and the cladding. Fuel plates were also produced and characterized with a silicon-rich interlayer between fuel and cladding. This paper reports the recent progress of this developmental effort and identifies the areas that need further attention.

  8. Canning Of Powdered Metal For Hot Isostatic Pressing

    NASA Technical Reports Server (NTRS)

    Juhas, John J.

    1989-01-01

    Quality of specimen enhanced by improved canning process. Method developed for canning specimens for hot isostatic pressing. Specimen placed inside refractory-metal ring, then sandwiched between two refractory-metal face sheets. Assembly placed inside die, then positioned in vacuum hot press. Heated to set temperature at prescribed vacuum to burn off all of binder in specimen. Advantages: powder-metallurgy composite totally purged of binder sealed in can in single operation, maintains size, shape, and uniformity of specimen. Weld region does not recrystallize, and little possibility of cracking.

  9. Effect of hot isostatic pressing on RBa sub 2 Cu sub 3 O sub 7 superconductors

    SciTech Connect

    Sadananda, K.; Singh, A.K.; Iman, M.A.; Osofsky, M.; Le Tourneau, V.; Richards, L.E. )

    1988-09-01

    In an effort to make dense, consolidated superconductors, the hot isostatic pressing process was applied to the RBa{sub 2}Cu{sub 3}O{sub 7} system, where R is a rare-earth element. The authors have demonstrated the applicability of the hot isostatic pressing process to produce a fine-grained consolidated solid which can be cut into any desired form. The grain refinement that occurred during hot isostatic pressing was related to the fracture of coarse-grained particles during pressurization. Hot isostatic pressing combined with post-annealing increased the superconducting onset temperature to >95 K. Because of the grain refinement and the higher {Tc} achieved, the superconductor material processed by hot isostatic pressing is also expected to have higher current density, J{sub c}, than its sintered counterpart. The hot isostatic pressing process was also used successfully for the system Bi-Sr-Ca-Cu-O to make dense, bulk superconducting material.

  10. Bibliography on Hot Isostatic Pressing (HIP) technology. Special report

    SciTech Connect

    Gilp, B.F.; Desai, P.D.; Radavich, J.F.; Ho, C.Y.

    1992-11-01

    This report contains an annotated bibliography of 950 documents on the Hot Isostatic Pressing (HIP) Technology dealing with metals, alloys, and intermetallic compounds and covers over 450 materials. Documents published from 1966 to early 1992 are covered. Bibliographic information reported here are divided into three broad categories. The first category includes an annotated bibliography dealing with HIP technology as applied to powder metallurgy. The second category deals with casting and the third deals with miscellaneous materials which either are not properly identified or have a limited number of bibliographic citations. Within each category, bibliographic information is organized according to major alloy groups, e.g., aluminum alloys, beryllium alloys, cobalt alloys, etc., followed by bibliographies for miscellaneous alloys which are alloys either not properly identified or not having enough data to warrant a separate category. Each alloy group is further subdivided into individual commercial alloys, e.g., aluminum alloys AA 2024, AA 7075, AA 7090, etc., followed by miscellaneous aluminum alloys. Bibliography, Hot Isostatic Pressing (HIP), Powder metallurgy, Castings, Metals, Alloys, Intermetallics, Mechanical properties, Processing, Beryllium alloys, Titanium alloys, Aluminum alloys, Cobalt alloys, Refractory alloys, Steels.

  11. High-pressure combinatorial process integrating hot isostatic pressing.

    PubMed

    Fujimoto, Kenjiro; Morita, Hiroki; Goshima, Yuji; Ito, Shigeru

    2013-12-01

    A high-pressure combinatorial process integrating hot isostatic pressing (HIP) was developed by providing a reaction vessel with a high-pressure tightness based on a commercial flange. The reaction vessel can be used up to 200 MPa and 500 °C under HIP processing condition. Preparation of spinel-type MgAl2O4 from Mg(OH)2, Al(OH)3 and AlOOH was performed using the reaction vessel under 200 MPa and 500 °C as demonstration. The entire powder library was characterized using powder X-ray diffraction patterns, and the single phase of spinel-type MgAl2O4 was obtained from Mg(OH)2+Al(OH)3. These assessments corresponded with previously published data. PMID:24168067

  12. Effect of hot isostatic pressing on reaction-bonded silicon nitride

    NASA Technical Reports Server (NTRS)

    Watson, G. K.; Moore, T. J.; Millard, M. L.

    1984-01-01

    Specimens of nearly theoretical density have been obtained through the isostatic hot pressing of reaction-bonded silicon nitride under 138 MPa of pressure for two hours at 1850, 1950, and 2050 C. An amorphous phase that is introduced by the hot isostatic pressing partly accounts for the fact that while room temperature flexural strength more than doubles, the 1200 C flexural strength increases significantly only after pressing at 2050 C.

  13. High-strength silicon carbides by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Dutta, Sunil

    1988-01-01

    Silicon carbide has strong potential for heat engine hardware and other high-temperature applications because of its low density, good strength, high oxidation resistance, and good high-temperature creep resistance. Hot isostatic pressing (HIP) was used for producing alpha and beta silicon carbide (SiC) bodies with near-theoretical density, ultrafine grain size, and high strength at processing temperatures of 1900 to 2000 C. The HIPed materials exhibited ultrafine grain size. Furthermore, no phase transformation from beta to alpha was observed in HIPed beta-SiC. Both materials exhibited very high average flexural strength. It was also shown that alpha-SiC bodies without any sintering aids, when HIPed to high final density, can exhibit very high strength. Fracture toughness K (sub C) values were determined to be 3.6 to 4.0 MPa m (sup 1/2) for HIPed alpha-SiC and 3.7 to 4.1 MPa m (sup 1/2) for HIPed beta-SiC. In the HIPed specimens strength-controlling flaws were typically surface related. In spite of improvements in material properties such as strength and fracture toughness by elimination of the larger strength-limiting flaws and by grain size refinement, HIPing has no effect on the Weibull modulus.

  14. High-strength silicon carbides by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Dutta, Sunil

    1989-01-01

    Silicon carbide has strong potential for heat engine hardware and other high-temperature applications because of its low density, good strength, high oxidation resistance, and good high-temperature creep resistance. Hot isostatic pressing (HIP) was used for producing alpha and beta silicon carbide (SiC) bodies with near-theoretical density, ultrafine grain size, and high strength at processing temperatures of 1900 to 2000 C. The HIPed materials exhibited ultrafine grain size. Furthermore, no phase transformation from beta to alpha was observed in HIPed beta-SiC. Both materials exhibited very high average flexural strength. It was also shown that alpha-SiC bodies without any sintering aids, when HIPed to high final density, can exhibit very high strength. Fracture toughness K (sub C) values were determined to be 3.6 to 4.0 MPa m (sup 1/2) for HIPed alpha-SiC and 3.7 to 4.1 MPa m (sup 1/2) for HIPed beta-SiC. In the HIPed specimens strength-controlling flaws were typically surface related. In spite of improvements in material properties such as strength and fracture toughness by elimination of the larger strength-limiting flaws and by grain size refinement, HIPing has no effect on the Weibull modulus.

  15. Process and equipment development for hot isostatic pressing treatability study

    SciTech Connect

    Bateman, Ken; Wahlquist, Dennis; Malewitz, Tim

    2015-03-01

    Battelle Energy Alliance (BEA), LLC, has developed processes and equipment for a pilot-scale hot isostatic pressing (HIP) treatability study to stabilize and volume reduce radioactive calcine stored at Idaho National Laboratory (INL). In 2009, the U. S. Department of Energy signed a Record of Decision with the state of Idaho selecting HIP technology as the method to treat 5,800 yd^3 (4,400 m^3) of granular zirconia and alumina calcine produced between 1953 and 1992 as a waste byproduct of spent nuclear fuel reprocessing. Since the 1990s, a variety of radioactive and hazardous waste forms have been remotely treated using HIP within INL hot cells. To execute the remote process at INL, waste is loaded into a stainless-steel or aluminum can, which is evacuated, sealed, and placed into a HIP furnace. The HIP simultaneously heats and pressurizes the waste, reducing its volume and increasing its durability. Two 1 gal cans of calcine waste currently stored in a shielded cask were identified as candidate materials for a treatability study involving the HIP process. Equipment and materials for cask-handling and calcine transfer into INL hot cells, as well as remotely operated equipment for waste can opening, particle sizing, material blending, and HIP can loading have been designed and successfully tested. These results demonstrate BEA’s readiness for treatment of INL calcine.

  16. Summary of Calcine Disposal Development Using Hot Isostatic Pressing

    SciTech Connect

    Bateman, Ken; Wahlquist, Dennis; Hart, Edward; McCartin, William

    2015-03-01

    Battelle Energy Alliance, LLC, has demonstrated the effectiveness of the hot isostatic press (HIP) process for treatment of hazardous high-level waste known as calcine that is stored at the Idaho Nuclear Technology and Engineering Center (INTEC) at Idaho National Laboratory. HIP trials performed with simulated calcines at Idaho National Laboratory’s Materials and Fuels Complex and an Australian Nuclear Science and Technology Organization facility from 2007 to 2010 produced a dense, monolithic waste form with increased chemical durability and effective (storage) volume reductions of ~10 to ~70% compared to granular calcine forms. In December 2009, the U.S. Department of Energy signed an amended Record of Decision selecting HIP technology as the treatment method for the 4,400 m3 of granular zirconia and alumina calcine stored at INTEC. Testing showed that HIP treatment reduces the risks associated with radioactive and hazardous constituent release, post-production handling, and long-term (repository) storage of calcines and would result in estimated storage cost savings in the billions of dollars. Battelle Energy Alliance has the ability to complete pilot-scale HIP processing of INTEC calcine, which is the next necessary step in implementing HIP processing as a calcine treatment method.

  17. Fracture toughness of CIP-HIP (cold isostatic pressed - hot isostatic pressed) beryllium at elevated temperatures. Final report, 13 May 1980-13 February 1981

    SciTech Connect

    Barker, L.M.; Jones, A.H.

    1986-04-01

    The fracture toughness of CIP-HIP (cold isostatic pressed-hot isostatic pressed) beryllium was determined using the short-bar fracture-toughness (K/sub IcSB/) method. The K/sub IcSB/ value measured was 10.96 MPa x the square root of m at room temperature. This falls well within the expected range of 9 to 12 MPa x the square root of m as observed from previous fracture toughness measurements of beryllium. Toughness increased rapidly between 400 F and 500 F reaching a value of 16.7 MPa x the square root of m at 500 F.

  18. Microstructure-mechanical property relationships in hot isostatically pressed alumina and zirconia-toughened alumina

    SciTech Connect

    Shin, D.W.; Orr, K.K. ); Schubert, H. )

    1990-05-01

    The rates of densification and the mechanical properties of pure Al{sub 2}O{sub 3} and ZrO{sub 2}-toughened Al{sub 2}O{sub 3} (ZTA) have been investigated as a function of the temperatures and time schedules used for hot isostatic pressing (HIP) as a postsintering heat treatment for samples which had already been pressureless sintered in air at 1460{degrees}C for 45 min. ZTA hot isostatically pressed at 1400{degrees}C had a finer grain size and a narrower grain size distribution than ZTA hot isostatically pressed at 1600{degrees}C. At both HIP conditions, the density which could be obtained was almost the maximum theoretical density. The amount of grinding-induced and fracture-induced monoclinic ZrO{sub 2} formed as a result of the tetragonal {r arrow} monoclinic martensitic transformation in ZTA was higher in the samples hot isostatically pressed at 1400{degrees}C. ZTA hot isostatically pressed at 1600{degrees}C and 100 MPa had fewer flaws and higher strengths than ZTA hot isostatically pressed at 1400{degrees}C for the same time, with a gradual improvement in mechanical properties with increasing HIP time at each of these two temperatures.

  19. Removal of glass adhered to sintered ceramics in hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    In the hot isostatic pressing of ceramic materials in molten glass using an inert gas as a pressing medium, glass adhered to the sintered ceramics is heated to convert it to a porous glass and removed. Thus, Si3N4 powder was compacted at 5000 kg/sq cm, coated with a 0.5 mm thick BN, embedded in Pyrex glass in a graphite crucible, put inside a hot isostatic press containing Argon, hot pressed at 1750 C and 100 kg/sq cm; cooled, taken out from the crucible, heated at 1100 C for 30 minutes, cooled, and then glass adhered to the sintered body was removed.

  20. Hot isostatic pressing of direct selective laser sintered metal components

    NASA Astrophysics Data System (ADS)

    Wohlert, Martin Steven

    2000-10-01

    A new manufacturing process combining the benefits of Selective Laser Sintering (SLS) and Hot Isostatic Pressing (HIP) has been developed to permit Rapid Prototyping of high performance metal components. The new process uses Direct Metal SLS to produce a gas impermeable HIP container from the same powdered material that will eventually compose the bulk of the part. The SLS generated capsule performs the functions of the sheet metal container in traditional HIP, but unlike a sheet metal container, the SLSed capsule becomes an integral part of the final component. Additionally, SLS can produce a capsule of far greater geometric complexity than can be achieved by sheet metal forming. Two high performance alloys, Ti-6Al-4V and Inconel 625, were selected for use in the development of the new process. HIP maps were constructed to predict the densification rate of the two materials during HIP processing. Comparison to experimentally determined densification behavior indicated that the maps provide a useful qualitative description of densification rates; however, the accuracy of quantitative predictions was greatly enhanced by tuning key material parameters based on a limited number of experimental HIP cycles. Microstructural characterization of SLS + HIP samples revealed two distinct regions within the components. The outer SLS processed capsule material exhibited a relatively coarse microstructure comparable to a cast, or multi-layer welded structure. No layer boundaries were discernible in the SLS material, with grains observed to grow epitaxially from previously deposited material. The microstructure of the HIP consolidated core material was similar to conventionally HIP processed powder materials, featuring a fine grain structure and preserved prior particle boundaries. The large variation in grain size between the capsule and core materials was reflected in hardness measurements conducted on the Alloy 625 material; however, the variation in hardness was less

  1. Manufacturing near dense metal parts via indirect selective laser sintering combined with isostatic pressing

    NASA Astrophysics Data System (ADS)

    Liu, J. H.; Shi, Y. S.; Lu, Z. L.; Huang, S. H.

    2007-11-01

    To fabricate metal parts via indirect selective laser sintering (SLS), isostatic pressing technology, including hot isostatic pressing (HIP) and cold isostatic pressing (CIP), are exploited to reform SLS green parts and make them near dense. The processes of SLS/HIP and SLS/CIP/HIP technologies are investigated respectively and the densification of AISI304 stainless steel specimens is mainly discussed. It is indicated that green parts made by indirect SLS can be pressed into near dense parts with the relative densities of 67.3% and more than 80% in SLS/HIP and SLS/CIP/HIP routes, respectively, and their densities rise if much higher CIP pressure is employed. Compared with SLS/HIP, SLS/CIP/HIP technology is regarded as a better method to manufactured dense parts, and it enlarges the application domain of indirect SLS simultaneously.

  2. High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

    NASA Astrophysics Data System (ADS)

    Hoenig, C. L.

    1990-06-01

    Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800 C and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

  3. High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, Clarence L.

    1993-01-01

    Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

  4. High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, C.L.

    1993-08-31

    Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1,800 C and 30 PSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

  5. High density-high purity graphite prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, C.L.

    1994-08-09

    Porous graphite in solid form is hot isostatically pressed in a refractory metal container to produce a solid graphite monolith with a bulk density greater than or equal to 2.10 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed, chemically vapor deposited, or coated by some other suitable means onto graphite. Hot isostatic pressing at 2,200 C and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. Complex shapes can be made. 1 fig.

  6. High density-high purity graphite prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, Clarence L.

    1994-01-01

    Porous graphite in solid form is hot isostatically pressed in a refractory metal container to produce a solid graphite monolith with a bulk density greater than or equal to 2.10 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed, chemically vapor deposited, or coated by some other suitable means onto graphite. Hot isostatic pressing at 2200.degree. C. and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. Complex shapes can be made.

  7. Preparation of SiC-Based Composites by Cold Isostatic Press

    NASA Astrophysics Data System (ADS)

    Harun, M. B.; Halim, M. H.; Yazid, H.; Selamat, Z.; Sattar, M. S.; Jali, M.

    2010-03-01

    The effect of polyvinyl alcohol binder on green strength of isostatic pressed silicon carbide was studied. A lab-top spray dryer was used to coat mixed powders with the binder. The resultant powders were pressed in a steel die to obtain pre-mold at the compaction pressures of 32, 63.5, 127, 190, 254 and 317 MPa. The pre-molds were pressed using a cold isostatic press at 276 MPa to produce the green compact specimens. The porosities and compression stress of the green compact specimens produced from laboratory powder were compared with compacted specimens produced with commercial powder. Density porosimetry and universal testing machine were used to determine porosity and compression stress; respectively. The morphology and fracture surface of the green compact specimens were observed under optical and electron microscopes.

  8. Development of monolithic nuclear fuels for RERTR by hot isostatic pressing

    SciTech Connect

    Jue, J.-F.; Park, Blair; Chapple, Michael; Moore, Glenn; Keiser, Dennis

    2008-07-15

    The RERTR Program (Reduced Enrichment for Research and Test Reactors) is developing advanced nuclear fuels for high power test reactors. Monolithic fuel design provides a higher uranium loading than that of the traditional dispersion fuel design. In order to bond monolithic fuel meat to aluminum cladding, several bonding methods such as roll bonding, friction stir bonding and hot isostatic pressing, have been explored. Hot isostatic pressing is a promising process for low cost, batch fabrication of monolithic RERTR fuel plates. The progress on the development of this process at the Idaho National Laboratory will be presented. Due to the relatively high processing temperature used, the reaction between fuel meat and aluminum cladding to form brittle intermetallic phases may be a concern. The effect of processing temperature and time on the fuel/cladding reaction will be addressed. The influence of chemical composition on the reaction will also be discussed. (author)

  9. Effect of Surface Preparation on CLAM/CLAM Hot Isostatic Pressing diffusion bonding joints

    NASA Astrophysics Data System (ADS)

    Li, C.; Huang, Q.; Zhang, P.

    2009-04-01

    Surface preparation is essential for the Hot Isostatic Pressing (HIP) diffusion bonding of RAFM steels. Hot Isostatic Pressing (HIP) diffusion bonding experiments on China Low Activation Martensitic (CLAM) steel was performed to study the effect of surface preparation. A few approaches such as hand lapping, dry-milling and grinding etc., were used to prepare the faying surfaces of the HIP joints. Different sealing techniques were used as well. The HIP parameters were 150 MPa/3 h/1150 °C. After post HIP heat treatment (PHHT), the tensile and Charpy impact tests were carried out. The results showed that hand lapping was not suitable to prepare the faying surfaces of HIP diffusion bonding specimens although the surface roughness by hand lapping was very low.

  10. High density hexagonal boron nitride prepared by hot isostatic pressing in refractory metal containers

    SciTech Connect

    Hoenig, C.L.

    1990-12-31

    Boron nitride powder with less than or equal to the oxygen content of starting powder (down to 0.5% or less) is hot isostatically pressed in a refractory metal container to produce hexagonal boron nitride with a bulk density greater than 2.0 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a cansister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800{degrees}C and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.21 g/cc. Complex shapes can be made.

  11. High density hexagonal boron nitride prepared by hot isostatic pressing in refractory metal containers

    DOEpatents

    Hoenig, Clarence L.

    1992-01-01

    Boron nitride powder with less than or equal to the oxygen content of starting powder (down to 0.5% or less) is hot isostatically pressed in a refractory metal container to produce hexagonal boron nitride with a bulk density greater than 2.0 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.21 g/cc. Complex shapes can be made.

  12. Hot Isostatic Press Manufacturing Process Development for Fabrication of RERTR Monolithic Fuel Plates

    SciTech Connect

    Crapps, Justin M.; Clarke, Kester D.; Katz, Joel D.; Alexander, David J.; Aikin, Beverly; Vargas, Victor D.; Montalvo, Joel D.; Dombrowski, David E.; Mihaila, Bogdan

    2012-06-06

    We use experimentation and finite element modeling to study a Hot Isostatic Press (HIP) manufacturing process for U-10Mo Monolithic Fuel Plates. Finite element simulations are used to identify the material properties affecting the process and improve the process geometry. Accounting for the high temperature material properties and plasticity is important to obtain qualitative agreement between model and experimental results. The model allows us to improve the process geometry and provide guidance on selection of material and finish conditions for the process strongbacks. We conclude that the HIP can must be fully filled to provide uniform normal stress across the bonding interface.

  13. Low-temperature Mechanical Properties of Bulk MgB2 Fabricated by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Murakami, A.; Teshima, H.; Naito, T.; Fujishiro, H.; Kudo, T.; Iwamoto, A.

    Mechanical properties ina MgB2superconducting bulk sample,whose packing ratio is 92%,fabricated by hot isostatic pressing (HIP)areevaluated at 77 K through bending tests.The fracture strength at 77 K is higher than at room temperature. From the bending test result at 77 K, the fracture strength of ideal bulk MgB2,whose packing ratio is 100%,is estimated. The fracture strength at very low temperature of the HIP bulk MgB2is also estimated from the bending test results at 77 K and room temperature.

  14. Hot isostatically pressed manufacture of high strength MERL 76 disk and seal shapes

    NASA Technical Reports Server (NTRS)

    Eng, R. D.; Evans, D. J.

    1982-01-01

    The feasibility of using MERL 76, an advanced high strength direct hot isostatic pressed powder metallurgy superalloy, as a full scale component in a high technology, long life, commercial turbine engine were demonstrated. The component was a JT9D first stage turbine disk. The JT9D disk rim temperature capability was increased by at least 22 C and the weight of JT9D high pressure turbine rotating components was reduced by at least 35 pounds by replacement of forged Superwaspaloy components with hot isostatic pressed (HIP) MERL 76 components. The process control plan and acceptance criteria for manufacture of MERL 76 HIP consolidated components were generated. Disk components were manufactured for spin/burst rig test, experimental engine tests, and design data generation, which established lower design properties including tensile, stress-rupture, 0.2% creep and notched (Kt = 2.5) low cycle fatigue properties, Sonntag, fatigue crack propagation, and low cycle fatigue crack threshold data. Direct HIP MERL 76, when compared to conventionally forged Superwaspaloy, is demonstrated to be superior in mechanical properties, increased rim temperature capability, reduced component weight, and reduced material cost by at least 30% based on 1980 costs.

  15. Influence of hot isostatic pressing on ZrO2-CaO dental ceramics properties.

    PubMed

    Gionea, Alin; Andronescu, Ecaterina; Voicu, Georgeta; Bleotu, Coralia; Surdu, Vasile-Adrian

    2016-08-30

    Different hot isostatic pressing conditions were used to obtain zirconia ceramics, in order to assess the influence of HIP on phase transformation, compressive strength, Young's modulus and density. First, CaO stabilized zirconia powder was synthesized through sol-gel method, using zirconium propoxide, calcium isopropoxide and 2-metoxiethanol as precursors, then HIP treatment was applied to obtain final dense ceramics. Ceramics were morphologically and structurally characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Density measurements, compressive strength and Young's modulus tests were also performed in order to evaluate the effect of HIP treatment. The zirconia powders heat treated at 500°C for 2h showed a pure cubic phase with average particle dimension about 70nm. The samples that were hot isostatic pressed presented a mixture of monoclinic-tetragonal or monoclinic-cubic phases, while for pre-sintered samples, cubic zirconia was the single crystalline form. Final dense ceramics were obtained after HIP treatment, with relative density values higher than 94%. ZrO2-CaO ceramics presented high compressive strength, with values in the range of 500-708.9MPa and elastic behavior with Young's modulus between 1739MPa and 4372MPa. Finally zirconia ceramics were tested for biocompatibility allowing the normal development of MG63 cells in vitro. PMID:26481467

  16. Expanded Analysis of Hot Isostatic Pressed Iodine-Loaded Silver-Exchanged Mordenite

    SciTech Connect

    Jubin, R. T.; Bruffey, S. H.; Patton, K. K.

    2014-09-30

    Reduced silver-exchanged mordenite (Ag0Z) is being evaluated as a potential material to control the release of radioactive iodine that is released during the reprocessing of used nuclear fuel into the plant off-gas streams. The purpose of this study was to determine if hot pressing could directly convert this iodine loaded sorbent into a waste form suitable for long-term disposition. The minimal pretreatment required for production of pressed pellets makes hot pressing a technically and economically desirable process. Initial scoping studies utilized hot uniaxial pressing (HUPing) to prepare samples of non-iodine-loaded reduced silver exchanged mordenite (Ag0Z). The resulting samples were very fragile due to the low pressure (~ 28 MPa) used. It was recommended that hot isostatic pressing (HIPing), performed at higher temperatures and pressures, be investigated. HIPing was carried out in two phases, with a third and final phase currently underway. Phase I evaluated the effects of pressure and temperature conditions on the manufacture of a pressed sample. The base material was an engineered form of silver zeolite. Six samples of Ag0Z and two samples of I-Ag0Z were pressed. It was found that HIPing produced a pressed pellet of high density. Analysis of each pressed pellet by scanning electron microscopy-energy dispersive spectrophotometry (SEM-EDS) and X-ray diffraction (XRD) demonstrated that under the conditions used for pressing, the majority of the material transforms into an amorphous structure. The only crystalline phase observed in the pressed Ag0Z material was SiO2. For the samples loaded with iodine (I-Ag0Z) iodine was present as AgI clusters at low temperatures, and transformed into AgIO4 at high temperatures. Surface mapping and EDS demonstrate segregation between silver iodide phases and silicon dioxide phases. Based on the results of the Phase I study, an expanded test matrix was developed to examine the effects of multiple source materials, compositional

  17. Microstructure and Phase Composition of Cold Isostatically Pressed and Pressureless Sintered Silicon Nitride.

    PubMed

    Lukianova, O A; Krasilnikov, V V; Parkhomenko, A A; Sirota, V V

    2016-12-01

    The microstructure and physical properties of new Y2O3 and Al2O3 oxide-doped silicon nitride ceramics fabricated by cold isostatic pressing and free sintering were investigated. The phase composition of produced material was also studied by X-ray diffraction at room and elevated temperature. The fabricated ceramics featured a microstructure of Si5AlON7 grains with a fine-grained α-Si3N4 with a small amount of Y2SiAlON5. Described ceramics is attractive for many high-temperature structural applications due to beneficial combination of fine-grained structure with improved mechanical properties and small weight loss. PMID:26979726

  18. Manufacture of die casting dies by hot isostatic pressing. CRADA final report

    SciTech Connect

    Viswanathan, S.; Ren, W.; Luk, K.; Brucher, H.G.

    1998-09-01

    The reason for this Cooperative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory (ORNL) and Doehler-Jarvis was to investigate the manufacture die-casting dies with internal water-cooling lines by hot-isostatic pressing (HIPing) of H13 tool steel powder. The use of HIPing will allow the near-net-shape manufacture of dies and the strategic placement of water-cooling lines during manufacture. The production of near-net-shape dies by HIPing involves the generation of HIPing diagrams, the design of the can that can be used for HIPing a die with complex details, strategic placement of water-cooling lines in the die, computer modeling to predict movement of the water lines during HIPing, and the development of strategies for placing water lines in the appropriate locations. The results presented include a literature review, particle analysis and characterization of H13 tool steel powder, and modeling of the HIPing process.

  19. Microstructure and Phase Composition of Cold Isostatically Pressed and Pressureless Sintered Silicon Nitride

    NASA Astrophysics Data System (ADS)

    Lukianova, O. A.; Krasilnikov, V. V.; Parkhomenko, A. A.; Sirota, V. V.

    2016-03-01

    The microstructure and physical properties of new Y2O3 and Al2O3 oxide-doped silicon nitride ceramics fabricated by cold isostatic pressing and free sintering were investigated. The phase composition of produced material was also studied by X-ray diffraction at room and elevated temperature. The fabricated ceramics featured a microstructure of Si5AlON7 grains with a fine-grained α-Si3N4 with a small amount of Y2SiAlON5. Described ceramics is attractive for many high-temperature structural applications due to beneficial combination of fine-grained structure with improved mechanical properties and small weight loss.

  20. Manufacture of astroloy turbine disk shapes by hot isostatic pressing, volume 1

    NASA Technical Reports Server (NTRS)

    Eng, R. D.; Evans, D. J.

    1978-01-01

    The Materials in Advanced Turbine Engines project was conducted to demonstrate container technology and establish manufacturing procedures for fabricating direct Hot Isostatic Pressing (HIP) of low carbon Astroloy to ultrasonic disk shapes. The HIP processing procedures including powder manufacture and handling, container design and fabrication, and HIP consolidation techniques were established by manufacturing five HIP disks. Based upon dimensional analysis of the first three disks, container technology was refined by modifying container tooling which resulted in closer conformity of the HIP surfaces to the sonic shape. The microstructure, chemistry and mechanical properties of two HIP low carbon Astroloy disks were characterized. One disk was subjected to a ground base experimental engine test, and the results of HIP low carbon Astroloy were analyzed and compared to conventionally forged Waspaloy. The mechanical properties of direct HIP low carbon Astroloy exceeded all property goals and the objectives of reduction in material input weight and reduction in cost were achieved.

  1. Superior austempered ductile iron (ADI) properties achieved by prior hot isostatic pressing (HIP)

    SciTech Connect

    LaGoy, J.L.; Widmer, R.; Zick, D.H.

    1996-12-31

    Ductile iron obtained from different foundries and cast by dissimilar methods has been successfully hot isostatically pressed (HIPed) before austempering to achieve substantially higher ductilities, without significant detriment to other properties, than those reached by austempering along. HIP was attempted to solve different mechanical deficiencies in austempered ductile iron (ADI) such as the lack of ductility in higher strength grades, inconsistent mechanical properties, and service life limitations. A variety of HIP temperatures were analyzed from near the austenitizing region up to within 56 C (100 F) of the melting point of ductile iron. Microporosity was eliminated by HIP at all temperatures, and subsequent austempering revealed a uniform ADI microstructure. HIP proved successful with both unencapsulated castings and those enclosed within steel canisters. Additional benefits caused by HIP processing of ductile iron castings without the austempering treatment include a significant decrease in mechanical property data scatter, high hardness at reasonable ductility levels, and a substantially reduced scrap rate.

  2. Friction welding method of hot isostatic press can closure for the ICPP calcine immobilization program

    SciTech Connect

    Berry, S.M.; Reed, T.R.; Swainston, R.C

    1993-09-01

    An investigation of various closure techniques was performed in an effort to meet requirements for closure of evacuated waste cans to be used at Westinghouse Idaho Nuclear Company`s Idaho Chemical Processing Plant. Although other sealing techniques are available, welding was considered to be the best for sealing the cans. For various reasons. techniques other than welding are not suitable for cans that are subject to the Hot Isostatic Press (HIP) process. For example. elastomeric seals. solders. and brazing would,not withstand the temperature associated (approximately 1000 degrees centigrade) with the HIP process. Mechanical joining techniques such as threading, crimping, and swaging could result in the joint opening as the can wall is deformed during HIP process. Unlike the above joint methods, welding results in physical joining of the lid or plug to the can itself, thus the wall would have to be ruptured before leakage would occur. This document investigates welding techniques for application to the can closure.

  3. Investigation of Porosity Changes in Cast Ti6Al4V Rods After Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    du Plessis, Anton; Rossouw, Pierre

    2015-08-01

    The porosities of cast Ti6Al4V rods were investigated nondestructively using x-ray microcomputed tomography (microCT) before and after HIP. This allowed the visualization and quantification of porosity changes in the same samples, which indicate excellent pore closure for large pores. This is the first reported application of x-ray microCT for direct analysis of investment casting porosity before and after HIP. The method shows promise for further investigations using delayed HIP treatments or monitoring of pore closure at further varying HIP cycle settings. The nondestructive nature of the analysis has resulted in the interesting observation of small subsurface pores (<250 μm) unaffected by hot isostatic pressing in two of the samples.

  4. Mechanical properties of molybdenum disilicide based materials consolidated by hot isostatic pressing (HIP)

    SciTech Connect

    Suryanarayanan, R.; Sastry, S.M.L.; Jerina, K.L. . Dept. of Mechanical Engineering)

    1994-11-01

    The influence of hot isostatic pressing (HIP) consolidation parameters on the mechanical properties of molybdenum disilicide (MoSi[sub 2]) and MoSi[sub 2] reinforced with ductile and brittle reinforcements was studied. MoSi[sub 2], MoSi[sub 2]-20 vol.% coarse and fine niobium powder and MoSi[sub 2]-20 vol.% silicon carbide whiskers consolidated by HIP at 1,200--1,400 C, 207 MPa, for 1 and 4 h were tested in compression for elevated temperature strength and creep resistance. Single-edge-notched specimens of the three materials were tested in a three-point bend configuration for fracture toughness. Mechanical properties were related with consolidation parameters and post-HIP microstructures.

  5. Evaluation of hot isostatic pressing for joining of fusion reactor structural components

    NASA Astrophysics Data System (ADS)

    Ivanov, A. D.; Sato, S.; Le Marois, G.

    2000-12-01

    Hot isostatic pressing (HIP) is a promising technology to fabricate the blanket structure of fusion reactors. HIP joining of solid materials has been selected as a reference fabrication method for the shielding blanket/first wall of the international thermonuclear experimental reactor (ITER). On the basis of experimental results obtained in Europe, Japan and Russia, an evaluation of HIP joining for fusion reactor structural components has been carried out. The parameters of HIP fabrication for copper alloys and stainless steels are given. The results of microscopic observations, X-ray microanalysis, tensile, impact toughness, fracture toughness and fatigue tests are presented. Material science criteria for an estimation of quality for joints fabricated by HIP are discussed.

  6. Long rod penetration test of hot isostatically pressed Ti-based targets

    NASA Astrophysics Data System (ADS)

    Nesterenko, Vitali F.; Indrakanti, Sastry S.; Brar, Singh; Gu, YaBei

    2000-04-01

    Hot Isostatic Pressing (HIP) is one of the most efficient techniques to produce high quality materials from powders. Nevertheless there is a shortage of data on high-strain-rate behavior and penetration resistance of such materials. In this paper the results of penetration test with tungsten (93%) heavy alloy penetrators of solid and porous composite samples of Ti-6Al-4V alloy with different microstructures (Widmanstatten pattern and equiaxed) are presented. Penetration depth for HIPed materials is smaller than in baseline samples of Ti-6Al-4V alloy (forged rod MIL-T-9047G). Composite materials with alumina rods and tubes filled with B4C powders demonstrated a new features of penetration: projectile deflection with self sealing of hole and forced shear localization caused by tubes fracture. The results demonstrate the applicability of HIPing for Ti-based armor materials.

  7. Magnetic and magneto elastic properties of cobalt ferrite ceramic compacted through cold isostatic pressing

    NASA Astrophysics Data System (ADS)

    Indla, Srinivas; Chelvane, Arout; Das, Dibakar

    2016-05-01

    Nano crystalline CoFe2O4 powder was prepared by combustion synthesis method. As synthesized powder was calcined at an appropriate condition to remove the impurities and to promote phase formation. Phase pure CoFe2O4 powder was pressed into cylindrical rod at an applied pressure of 200 MPa using a cold isostatic pressing. Sintering of the green compact at 1350°c for 12 hrs resulted in sintered cylindrical rod with ~85% of the theoretical density. Single phase cubic spinel structure was observed in the powder x-ray diffraction pattern of the sintered pellet. Scanning electron micrographs (SEM) of the as sintered pellet revealed the microstructure to be composed of ferrite grains of average size ~4 µm. Saturation magnetization of 72 emu/g and coercivity of 355 Oe were observed for cobalt ferrite sample. The magnetostriction was measured on a circular disc (12mm diameter and 12mm length) with the strain gauge (350 Ω) mounted on the flat surface of the circular disc. Magnetostriciton of 180 ppm and strain derivative of 1 × 10-9 m/A were observed for the sintered CoFe2O4 sample.

  8. Hot-isostatic pressing of silicon carbide based multiphase composed materials

    SciTech Connect

    Jiang, D.L.; She, J.H.

    1995-10-01

    Silicon carbide (SiC) based ceramic composites with improved fracture toughness and increased flexure strength have been developed by incorporating some other non-oxide and oxide particles or some whiskers and fibers. Hot-Isostatic Pressing (HIP) has been identified as an important technology for strengthening carbide by surface modification. In this paper, Hot-pressed SiC-TiC with different densities and HIP-SiC/SiC(w) composites were post HIPped under a N{sub 2}-pressure of 200 MPa at 1,850 C for 1 h. The results showed that the open pores were closed and physical and mechanical properties such as density, flexure strength and toughness were obviously improved. For the SiC-TiC composites, the final density can be reached above 985 theoretical density, flexure strength and fracture toughness were increased by 100% and 30--50%, respectively. For the SiC/5vol%-SiC(w) composites, the final flexure strength and fracture toughness were increased from 595 MPa and 6.7 MPa {center_dot} m{sup 1/2} to 920 MPa and 8.5 MPa {center_dot} m{sup 1/2} separately. A possible reaction-HIP densification mechanism for SiC ceramics with open pores is proposed.

  9. Open flow hot isostatic pressing assisted synthesis of highly porous materials and catalysts

    NASA Astrophysics Data System (ADS)

    Siadati, Mohammad Hossein

    Open-flow hot isostatic pressing (OFHIP) technique is applied for synthesizing molecular sieves and highly porous catalytic materials. First, the isostatic pressure is applied to the starting material/catalyst precursor, and then heat is applied. Under this condition, as the organic components gradually decompose and leave the material, the voids left behind are immediately filled/replaced by the gas (pressure medium) in flow. This substitution warrants the preservation as well as the uniformity of the voids/pores. The result is a very porous material with very uniform pore size distribution. Another advantage is the production of the catalyst directly from the precursor, in the absence of solvent (neat), rendering the process simpler and less costly than previous processes. The entire process takes place under flow of the gas that is used as medium to develop the isostatic pressure. Consequently, the entire process, as well as the final product produced, is devoid of any undesirable residues. This endeavor also introduces a viable technique for mass-producing porous materials/catalysts. The resulting materials are termed "amorphous sulfide sieves" to reflect their unique properties that include high surface area, narrow pore size distribution and high activity. The catalysts are potentially licensable to all petroleum and petroleum chemical companies for a wide variety of environmental and product improvement purposes. The results obtained on unpromoted samples synthesized at 300°C indicate that as the synthesis pressure is increased, both surface area and catalytic activity of the materials produced increase. The increase in activity k value from 3 to 6 x 10-7 mol/g.s corresponds to increase in pressure from 100 to 800 psi, respectively. The N2 gas used as pressure medium results in highly porous materials but low activity. H 2 seems to be the ideal gas for both pressure medium and reducing agent. Co-promoted catalysts synthesized at 1400 psi and 300°C show

  10. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1985-01-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  11. Effect of reduced cobalt contents on hot isostatically pressed powder metallurgy U-700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1982-01-01

    The effect of reducing the cobalt content of prealloyed powders of UDIMET 700 (U-700) alloys to 12.7, 8.6, 4.3, and 0% was examined. The powders were hot isostatically pressed into billets, which were given heat treatments appropriate for turbine disks, namely partial solutioning at temperatures below the gamma prime solvus and four step aging treatments. Chemical analyses, metallographic examinations, and X-ray diffraction measurements were performed on the materials. Minor effects on gamma prime content and on room temperature and 650 C tensile properties were observed. Creep rupture lives at 650 C reached a maximum at the 8.4% concentration, while at 760 C a maximum in life was reached at the 4.3% cobalt level. Minimum creep rates increased with decreasing cobalt content at both test temperatures. Extended exposures at 760 and 815 C resulted in decreased tensile strengths and rupture lives for all alloys. Evidence of sigma phase formation was also found.

  12. High temperature mechanical performance of a hot isostatically pressed silicon nitride

    SciTech Connect

    Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J.

    1996-01-01

    Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

  13. Microstructure and mechanical properties of nickel aluminide powders consolidated by extrusion and hot isostatic pressing

    SciTech Connect

    Wright, R.N.; Knibloe, J.R.; Williamson, R.L.

    1990-01-01

    The influence of alloying additions of iron and chromium, alone and in combination with molybdenum and zirconium, on the heat treatment response and mechanical properties of powder metallurgy Ni{sub 3}Al based materials consolidated by hot extrusion has been characterized in detail. Consolidation of the nickel aluminide powders by hot isostatic pressing (HIP) has been examined as an alternative to extrusion. Densification has been simulated using a model that describes consolidation by the additive effects of plastic flow, power-law creep, boundary diffusion, and Nabarro-Herring and Coble creep. The model has been used to develop maps that describe densification for any combination of time, temperature, and pressure. The best available material property data and parameters from experiments have been used to develop maps that describe HIP consolidation experiments with reasonable accuracy. Finite element models were developed as an extension of the HIP map approach to provide detailed simulations of particle deformation during densification. Preliminary results for both monosized and bimodal particle distributions indicate that this particle level approach is useful for simulating microstructural development resulting from different combinations of consolidation parameters. 45 refs., 22 figs., 22 figs., 4 tabs.

  14. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Astrophysics Data System (ADS)

    Harf, Fredric H.

    1985-06-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of γ' particles in a γ matrix. The higher cobalt-content alloys contained larger amounts of the finest γ' particles, and had the lowest γ-γ' lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650°C, the rupture lives at 650 and 760°C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the γ' particle size distribution and the γ-γ' mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  15. Hot isostatic pressing of silicon nitride with boron nitride, boron carbide, and carbon additions

    NASA Technical Reports Server (NTRS)

    Mieskowski, Diane M.; Sanders, William A.

    1989-01-01

    Si3N4 test bars containing additions of BN, B4C, and C, were hot isostatically pressed in Ta cladding at 1900 and 2050 C to 98.9 percent to 99.5 percent theoretical density. Room-temperature strength data on specimens containing 2 wt pct BN and 0.5 wt pct C were comparable to data obtained for Si3N4 sintered with Y2O3, Y2O3 and Al2O3, or ZrO2. The 1370 C strengths were less than those obtained for additions of Y2O3 or ZrO2 but greater than those obtained from a combination of Y2O3 and Al2O3. SEM fractography indicated that, as with other types of Si3N4, room-temperature strength was controlled by processing flaws. The decrease in strength at 1370 C was typical of Si3N4 having an amorphous grain-boundary phase. The primary advantage of nonoxide additions appears to be in facilitating specimen removal from the Ta cladding.

  16. Hot Isostatic Pressing (HIP) Model Developments for P/M Alloy 690N{sub 2}

    SciTech Connect

    J.W. Sears; J. Xu

    2001-08-30

    Powder Metallurgy (P/M) Alloy 690N{sub 2}, the P/M derivative of Inconel 690 (IN 690), has been shown to have a higher elevated temperature yield strength and superior stress corrosion cracking (SCC) resistance than IN 690. The property improvements seen in P/M Alloy 690N{sub 2} are due to interstitial nitrogen strengthening and precipitation hardening resulting from the formation of fine titanium/chromium--carbo-nitrides. The application of P/M Alloy 690N{sub 2} has had limited use, because of the high costs involved in producing wrought products from powder. Hot Isostatic Pressing (HIP) modeling to produce near net shapes should provide a more economical route for exploiting the benefits of Alloy 690N{sub 2}. The efforts involved in developing and verifying the P/M Alloy 690N{sub 2} HIP model are disclosed. Key to the deployment of HIP modeling is the development of the method to fabricate HIP powder containers via laser powder deposition.

  17. A study on improving mechanical properties of porous HA tissue engineering scaffolds by hot isostatic pressing.

    PubMed

    Zhao, Jing; Xiao, Suguang; Lu, Xiong; Wang, Jianxin; Weng, Jie

    2006-12-01

    Various interconnected porous hydroxyapatite (HA) ceramic scaffolds are universally used to induct the tissue growth for bone repair and replacement, and serve to support the adhesion, transfer, proliferation and differentiation of cells. Impregnation of polyurethane sponges with a ceramic slurry is adopted to produce highly porous HA ceramic scaffolds with a 3D interconnected structure. However, high porosity always accompanies a decrease in the strength of the HA ceramic scaffolds. Therefore, it is significant to improve the strength of the HA ceramic scaffolds with highly interconnected porosity so that they are more suitable in clinical applications. In this work, highly porous HA ceramic scaffolds are first produced by the polymer impregnation approach, and subsequently further sintered by hot isostatic pressing (HIP). The phase composition, macro- and micro-porous structure, sintering and mechanical properties of the porous HA scaffolds are investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation analysis and compressive test. The experimental results show that the nanohardness and compressive strength of HIP-sintered porous HA ceramics are higher than those of commonly sintered HA scaffolds. The HIP technique can effectively improve the sintering property and densification of porous HA ceramic scaffolds, so inducing an increase in the compression strength. PMID:18458404

  18. Synthesis and densification of Ni{sub 3}(Si, Ti) intermetallics by hot isostatic pressing

    SciTech Connect

    Van Dyck, S.; Delaey, L.; Froyen, L.; Buekenhout, L.

    1996-12-31

    The production of complex parts from Ni{sub 3}(Si, Ti) intermetallic materials by reactive powder metallurgy offers significant advantages over more conventional processing techniques. The main problem associated with reactive powder metallurgy is controlling the exothermic reaction accompanying the synthesis of the intermetallic compound. The uncontrolled release of heat during the conversion of the reactants into nickel silicide leads to unacceptable deformation and melting of the part. The thermal evolution of a part during reactive synthesis of the intermetallic phase is described based on kinetic and heat transfer equations, giving the temperature and phase change as a function of the applied temperature cycle and the mass and size of the part under consideration. From this model, methods for controlling the exothermic reaction during synthesis are derived. When preparing nickel silicides by reactive powder metallurgy, the application of external pressure is required to eliminate porosity and to obtain good mechanical properties. The properties of materials produced by hot isostatic pressing, with different methods of reaction control, are compared to materials prepared from prealloyed powders. It is shown that by reactive HIP, materials can be obtained with a fracture strength exceeding 2,000 MPa.

  19. Hot isostatic pressing of SiC particulate reinforced metal matrix composites

    SciTech Connect

    Loh, N.L.; Wei, Z.; Xu, Z.

    1996-12-31

    Two as-cast SiC particulate reinforced A359-based composites were hot isostatically pressed for a fixed length of time but at various pressures (in the range 100--150 MPa) and temperatures (in the range 450--550 C). It was found that HIP treatment generally increased the ductility but reduced the yield stress drastically. The improvement of ductility was attributed to a reduction of the porosity levels. Quantitative image analyses showed that the HIP treatment reduced the porosity levels significantly. It is of interest to observe that increasing HIP temperature is more effective than increasing HIP pressure in terms of improvement in strength and ductility. Another interesting observation is that most eutectic Si particles were spheroidized during HIP. The spheroidization of Si was believed to contribute to the improvement of mechanical properties, because fracture initiation of the composites was observed to be related to either the breaking of Si particles or the debonding of Si particles from the nearby SiC particles.

  20. High cycle fatigue and fracture behaviour of a hot isostatically pressed nickel-based superalloy

    NASA Astrophysics Data System (ADS)

    Qiu, Chunlei; Wu, Xinhua

    2014-01-01

    Powder of a nickel-based superalloy, RR1000, has been hot isostatically pressed (HIPped) at a supersolvus temperature and post-HIP heat treated to produce different microstructures. Microstructures were investigated using a scanning electron microscope together with an energy dispersive X-ray spectrometer and a wave-length dispersive X-ray spectrometer. High cycle four-point bending fatigue and tension-tension fatigue tests have been performed on the fabricated samples. It was found that HIPped and aged samples showed the best four-point bending fatigue limit while HIPped and solution-treated and aged samples had the lowest fatigue limit. The four-point bending fatigue crack initiations all occurred from the sample surfaces either at the sites of inclusion clusters or by cleavage through large grains on the surfaces. The tension-tension fatigue crack initiation occurred mainly due to large hafnia inclusion clusters, with lower fatigue lives for samples where inclusions were closer to the surface. Crack initiation at the compact Al2O3 inclusion cluster led to a much higher fatigue life than found when cracks were initiated by large hafnia inclusion clusters. The tension-tension fatigue limits were shown to decrease with increased testing temperature (from room temperature to 700 °C).

  1. Microstructure and tensile properties of Fe3Al produced by combustion synthesis/hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Rabin, B. H.; Wright, R. N.

    1992-01-01

    Combustion synthesis was carried out in a hot isostatic press (HIP) in order to prepare near-theoretical density Fe3Al and Fe3Al + Cr alloys from elemental powder mixtures. The microstructures and room-temperature tensile properties of these materials were studied in the as-synthesized condition and after heat treatment. As-synthesized materials exhibit a fine, equiaxed grain structure with grain sizes typically less than 10 μm. Yield and ultimate tensile strengths were found to be significantly higher than what has been reported for conventionally processed materials having similar composition. Although lower ductility was generally observed, elongations exceeding 5 pct were obtained in heat-treated Cr-containing alloys. Fracture occurred predominantly by transgranular cleavage. The strengthening of these materials is attributed to the fine grain size resulting from combustion synthesis/HIP processing. Transmission electron microscopy (TEM) revealed the presence of two distinct populations of aluminum oxide particles in the material. Nanometer-sized oxides exist within grains that likely formed at prior iron particle boundaries, and a high density of larger oxides exist along grain boundaries that probably originated from surface oxides on the aluminum powder. The presence of the grain boundary oxides was qualitatively observed to provide resistance to grain growth.

  2. Long Rod Penetration Test of Hot Isostatically Pressed Ti-based Targets

    NASA Astrophysics Data System (ADS)

    Nesterenko, Vitali; Indrakanti, Sastry; Singh Brar, N.; Gu, Yabei

    1999-06-01

    Hot Isostatic Pressing (HIP) is one of the most efficient techniques to produce materials from powders. Nevertheless there is a shortage of data on high-strain-rate behavior and penetration resistance of such materials. In this paper the results of penetration test (tungsten rod, velocity 886-960 m/s, diameter D=4.98 mm, L/D=10) with solid and porous composite samples of Ti-6Al-4V alloy with different microstructures (Widmanstatten pattern and equiaxed) will be reported. Milling of rapidly solidified Ti-6Al-4V powders prior to HIPing ensured the equiaxed final microstructure with increased compressive yield strength and microhardness (1180 and 3370 MPa correspondingly). Interstitial content was suitable for armor applications in some of the processing routes. Penetration depth for HIPed materials(14-15 mm) is smaller than in baseline samples of Ti-6Al-4V alloy (forged rod MIL-T-9047G). The results demonstrate the applicability of HIPing for Ti-based composite armor materials.

  3. Cyclic fatigue resistance of yttria-stabilized tetragonal zirconia polycrystals with hot isostatic press processing.

    PubMed

    Koyama, Taku; Sato, Toru; Yoshinari, Masao

    2012-01-01

    This study investigated the influence of surface roughness and cyclic loading on fatigue resistance in Y-TZP subjected to hot isostatic pressing (HIP). Fifty Y-TZP cylinders 3.0 mm in diameter were divided into Group A (polished by centerless method; TZP-CP) or Group B (blasted and acid-etched: TZP-SB150E). Twenty five cp-titanium cylinders (Ti-SB150E) were used as a control. Static and cyclic tests were carried out according to ISO 14801. The cyclic fatigue test was performed in distilled water at 37°C. Surface morphology and roughness as well as crystal phase on the surfaces were also evaluated. Fracture force under the static test was 1,765N (TZP-CP), 1,220N (TZP-SB150E), and 850 N (yield force, Ti-SB150E). Fracture values under the cyclic test decreased to approximately 70% of those under the static tests. These results indicate that HIPed Y-TZP with a 3.0-mm diameter has sufficient durability for application to dental implants. PMID:23207222

  4. The effect of hot isostatic pressing on crack initiation, fatigue, and mechanical properties of two cast aluminum alloys

    SciTech Connect

    Rich, T.P.; Orbison, J.G.; Duncan, R.S.; Olivero, P.G.; Peterec, R.H.

    1999-06-01

    This article presents the results of an experimental materials testing program on the effect of hot isostatic pressing (HIP) on the crack initiation, fatigue, and mechanical properties of two cast aluminum alloys: AMS 4220 and 4225. These alloys are often used in castings for high temperature applications. Standard tensile and instrumented Charpy impact tests were performed at room and elevated temperatures. The resulting data quantify improvements in ultimate tensile strength, ductility, and Charpy impact toughness from the HIP process while indicating little change in yield strength for both alloys. In addition standard fracture mechanics fatigue tests along with a set of unique fatigue crack initiation tests were performed on the alloys. Hot isostatic pressing was shown to produce a significant increase in cycles to crack initiation for AMS 4225, while no change was evident in traditional da/dN fatigue crack growth. The data permits comparisons of the two alloys both with and without the HIP process.

  5. Preparation and Characterization of MgB2 Bulk Samples Using High-Energy Ball Milling and Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Rodrigues, D.; Senkowicz, B. J.; Hanson, J. M.; Larbalestier, D. C.; Hellstrom, E. E.

    2008-03-01

    MgB2 bulk samples were prepared using high-energy ball milling in nitrogen atmosphere followed by cold isostatic pressing and hot isostatic pressing to increase densification and grain connectivity. Higher values of critical current densities Jc at high magnetic fields could be obtained after milling than those obtained with unmilled bulk samples. Jc values around 20,000 A/cm2 at 7 T, 4.2 K were found for the MgB2 sample milled for 300 minutes compared to 1000 A/cm2 for the unmilled material. The milling increased electron scattering and resistivity, increasing the irreversibility field μ0Hirr of the samples. The milled samples showed higher values of μ0Hirr than the unmilled sample. However, the milled samples showed lower pinning strength than the unmilled sample as a result of their larger average grain size after HIP, in spite of their higher μ0Hirr.

  6. The Effectiveness of Hot Isostatic Pressing for Closing Porosity in Titanium Parts Manufactured by Selective Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Tammas-Williams, Samuel; Withers, Philip J.; Todd, Iain; Prangnell, Philip B.

    2016-05-01

    Ti-6Al-4V parts, produced by selective electron beam melting additive manufacturing, have been studied by X-ray computed tomography (XCT) to track pore closure during a standard hot isostatic pressing (HIPing) cycle. Comparison of repeated XCT scans before and after HIPing, on worst-case samples with different geometries, confirmed that all internal porosity was shrunk to below the resolution limit of the equipment used (~5 µm) following the HIPing cycle, apart from defects with surface connected ligaments.

  7. Microstructure and mechanical properties of hip-consolidated Rene 95 powders. [hot-isostatic pressed nickel-based powder metal

    NASA Technical Reports Server (NTRS)

    Shimanuki, Y.; Nishino, Y.; Masui, M.; Doi, H.

    1980-01-01

    The effects of heat-treatments on the microstructure of P/M Rene 95 (a nickel-based powder metal), consolidated by the hot-isostatic pressing (HIP), were examined. The microstructure of as-HIP'd specimen was characterized by highly serrated grain boundaries. Mechanical tests and microstructural observations reveal that the serrated grain boundaries improved ductility at both room and elevated temperatures by retarding crack propagation along grain boundaries.

  8. CuCrZr alloy microstructure and mechanical properties after hot isostatic pressing bonding cycles

    NASA Astrophysics Data System (ADS)

    Frayssines, P.-E.; Gentzbittel, J.-M.; Guilloud, A.; Bucci, P.; Soreau, T.; Francois, N.; Primaux, F.; Heikkinen, S.; Zacchia, F.; Eaton, R.; Barabash, V.; Mitteau, R.

    2014-04-01

    ITER first wall (FW) panels are a layered structure made of the three following materials: 316L(N) austenitic stainless steel, CuCrZr alloy and beryllium. Two hot isostatic pressing (HIP) cycles are included in the reference fabrication route to bond these materials together for the normal heat flux design supplied by the European Union (EU). This reference fabrication route ensures sufficiently good mechanical properties for the materials and joints, which fulfil the ITER mechanical specifications, but often results in a coarse grain size for the CuCrZr alloy, which is not favourable, especially, for the thermal creep properties of the FW panels. To limit the abnormal grain growth of CuCrZr and make the ITER FW fabrication route more reliable, a study began in 2010 in the EU in the frame of an ITER task agreement. Two material fabrication approaches have been investigated. The first one was dedicated to the fabrication of solid CuCrZr alloy in close collaboration with an industrial copper alloys manufacturer. The second approach investigated was the manufacturing of CuCrZr alloy using the powder metallurgy (PM) route and HIP consolidation. This paper presents the main mechanical and microstructural results associated with the two CuCrZr approaches mentioned above. The mechanical properties of solid CuCrZr, PM CuCrZr and joints (solid CuCrZr/solid CuCrZr and solid CuCrZr/316L(N) and PM CuCrZr/316L(N)) are also presented.

  9. Enhancement of the electrical characteristics of metal-free phthalocyanine films using cold isostatic pressing

    SciTech Connect

    Matsushima, Toshinori E-mail: adachi@cstf.kyushu-u.ac.jp; Adachi, Chihaya E-mail: adachi@cstf.kyushu-u.ac.jp; Esaki, Yu

    2014-12-15

    Spatial gaps between grains and other grains, substrates, or electrodes in organic electronic devices are one of the causes of the reduction in the electrical characteristics. In this study, we demonstrate that cold isostatic pressing (CIP) is an effective method to crush the gaps and enhance the electrical characteristics. CIP of metal-free phthalocyanine (H{sub 2}PC) films induced a decrease in the film thickness by 34%–40% because of the gap crush. The connection of smaller grains into a larger grain and planarization of the film surface were also observed in the CIP film. The crystal axes of the H{sub 2}PC crystallites were rearranged from the a-axis to the c-axis of the α-phase crystal structure in a direction perpendicular to the substrate by CIP, indicating favorable hole injection and transport in this direction because of a better overlap of π orbitals. Thermally stimulated current measurements showed that deep hole traps disappeared and the total hole-trap density decreased after CIP. These CIP-induced changes of the film thicknesses, crystal axes and the hole traps lead to a marked increase in the hole mobility of the H{sub 2}PC films from 2.0 × 10{sup −7} to 4.0 × 10{sup −4} cm{sup 2}/V s by 2000 times in the perpendicular direction. We believe that these findings are important for unveiling the underlying carrier injection and transport mechanisms of organic films and for enhancing the performance of future organic electronic devices.

  10. Densification of molybdenum and molybdenum alloy powders using hot isostatic pressing. Final technical report

    SciTech Connect

    Barranco, J.; Ahmad, I.; Isserow, S.; Warenchak, R.

    1985-08-01

    This study was conducted to determine a superior erosion-resistant gun-barrel liner material with improved properties at higher temperatures. Four categories of powders were examined: 1. TZM spherical containing 0.5 titanium, 0.08 zirconium, and 0.02 carbon (wt. % nominally), balance molybdenum (Mo), produced by REP (Rotating Electrode Process), PREP (Plasma Rotating Electrode Process), and PMRS (Plasma Melted and Rapidly Solidified); 2. Mo reduced 2 and 5 microns; 3. Mo-0.1% cobalt, co-reduced; 4. Mo-5 wt. % alumina (A12O3), dispersion strengthened. Hot Isostatic Pressing (HIP) densification occurred at 15-30 Ksi, 1300-1600 C, for 1.5 to 3.0 hours. The TZM REP/PREP powders (220/74 microns) were not fully densified even at 1600 C, 30 Ksi, 3 hours. Point-particle contact prevented complete void elimination. TZM PMRS powder (24.7 microns) achieved 99% of theoretical density while maintaining a small grain size (10.4 ASTM eq.) Bend deflection and fracture energies were approximately three times those for PREP powder at a bend rupture strength of about 120 Ksi. Mo reduced and Mo-0.1% Co powders showed less (or the same) ductility with increasing HIP temperatures. Fractures were intergranular with decreased bend rupture and compression strength. The Mo-5A1/sub 2/O/sub 3/ powder maintained a fine grain size (13 ASTM eq.), but with fracture energies usually less than 0.6 in.-lbs. Included are results from bending and compression testing with metallographic and fracture mode interpretation.

  11. Characterization of hot isostatically pressed Bi-Sr-Ca-Cu-O as a function of consolidation variables

    SciTech Connect

    Goretta, K.C.; Miller, D.J.; Poeppel, R.B. ); Nash, A.S. )

    1991-11-01

    Fully dense, bulk Bi{sub 2}Sr{sub 1.7}CaCu{sub 2}O{sub x} (2212) superconductor pellets were made by hot isostatic pressing in an inert atmosphere. Electron microscopy revealed that rotation and bending of the platelike 2212 grains were responsible for much of the densification. Under processing conditions of 825{degrees}C and 105 MPa, dense pellets were obtained in 15 min. Many dislocations, planar faults, and, perhaps, intergrowths of the Bi{sub 2}Sr{sub 2}CuO{sub x} phase were produced during pressing. The dislocations were largely present in subgrain boundaries when the pressing times were increased to 45--120 min.

  12. Ballistic Testing and High-Strain-Rate Properties of Hot Isostatically Pressed Ti-6Al-4V

    NASA Astrophysics Data System (ADS)

    Gu, YaBei; Nesterenko, Vitali F.; Indrakanti, Sastry S.

    2002-07-01

    Hot isostatically pressed (HIPed) Ti-6Al-4V powder based targets (including composites) have a good ballistic performance against long rod, conical and flat projectiles impact (velocity range approx 0.4 - 1km/s). Compared to baseline material (MIL-T-9047G), new features such as different shape of craters in long rod penetration tests were observed. The results of compression Hopkinson bar tests, cut from tested targets (final strain controlled tests and hat-shaped specimen tests) are presented with a goal to establish relations between ballistic performance and high strain rate properties of HIPed materials.

  13. Formation of stacked luminescent complex of 8-hydroxyquinoline molecules on hydroxyapatite coating by using cold isostatic pressing.

    PubMed

    Matsuya, Takehiko; Otsuka, Yuichi; Tagaya, Motohiro; Motozuka, Satoshi; Ohnuma, Kiyoshi; Mutoh, Yoshiharu

    2016-01-01

    Cold isostatic pressing successfully formed a chelate complex of 8-hydroxyquinoline (8 Hq) molecules on plasma-sprayed hydroxyapatite (HAp) coating by solid-state reaction. The complex emits a fluorescence peak at approximately 500 nm by UV irradiation. The red shift of the fluorescence was newly observed in the cases of highly compressed complex due to π - π stacking of aromatic ring in the molecular structure of 8 Hq. The immersed complex coating in Simulated Body Fluid (SBF) demonstrated amorphous apatite precipitation and kept its fluorescence property. PMID:26478295

  14. Microstructural and mechanical characteristics of W-2Ti and W-1TiC processed by hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Muñoz, A.; Savoini, B.; Tejado, E.; Monge, M. A.; Pastor, J. Y.; Pareja, R.

    2014-12-01

    W-2Ti and W-1TiC alloys were produced by mechanical alloying and consolidation by hot isostatic pressing. The composition and microstructural characteristics of these alloys were studied by X-ray diffraction, energy dispersion spectroscopy and scanning electron microscopy. The mechanical behavior of the consolidated alloys was characterized by microhardness measurements and three point bending tests. The mechanical characteristics of the W-2Ti alloy appear to be related to solution hardening. In W-1TiC, the residual porosity should be responsible for the poor behavior observed in comparison with W-2Ti.

  15. Structure and hot hardness of RuAl-based alloys produced by reactive sintering using hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Povarova, K. B.; Morozov, A. E.; Padalko, A. G.; Drozdov, A. A.

    2008-04-01

    The structure and hot hardness (at temperatures up to 1100°C) of RuAl-based powder alloys with 1 3 at % Ni, Mo, Re, or Ru are studied. The alloys are produced by the reactive sintering of cold-compacted bars and subsequent threefold isostatic pressing with intermediate annealing at 1500°C performed after the first hot isostatic pressing. The samples have a residual pore content of 1 2.5 vol % and are characterized by a micrononuniform distribution of base and alloying elements. The alloys with refractory metals, such as Re, Mo, or Ru, are found to have the maximum hardness at all temperatures under study. At low temperatures, the effect is more substantial; the hardness of the Re-containing alloys exceeds that of the other alloys by a factor of 1.3 3.6. The increase in the hardness related to solid-solution alloying becomes more substantial owing to the microinhomogeneity of the sintered powder alloys and weakens because of microporosity. Recommendations that allow the uniformity of the distribution of the base and alloying elements to be increased are given.

  16. Microstructure and Mechanical Properties of Al6061-31vol.% B4C Composites Prepared by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Xian, Yajiang; Pang, Xiaoxuan; He, Shixiong; Wang, Wei; Wang, Xin; Zhang, Pengcheng

    2015-10-01

    Fabrication of durable and usable composites with high content of B4C (up to 31vol.%) is quite challenging in several aspects including blending, cold isostatic pressing, and hot isostatic pressing (HIP), and especially the optimal HIP process is essential to achieve the metal matrix composite with desirable properties. The microstructure and mechanical properties of Al6061-31vol.% B4C with different particle sizes were investigated by scanning electron microscopy (SEM) and tensile testing, respectively. SEM analysis and quantitative measurements of the particle distribution reveal that B4C particles were uniformly distributed in the matrix without agglomeration when the HIP treatment temperature was about 580 °C, and x-ray diffraction also identified a dispersion of B4C particles as well as reaction products (AlB2 and Al3BC) in the composites. Microhardness of Al6061-31vol.% B4C composites was improved with B4C particle size, and the tensile strength of all the samples declined with an increase in B4C particle size. The contribution from different strengthening mechanisms was also discussed.

  17. Surface characterization and growth mechanism of laminated Ti 3SiC 2 crystals fabricated by hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Wu, Qiong; Li, Changsheng; Tang, Hua

    2010-09-01

    Laminated Ti 3SiC 2 crystals were prepared by hot isostatic pressing from Ti, Si, C and Al powders with NaCl additive in argon at 1350 °C. The morphology and microstructure of Ti 3SiC 2 crystals were investigated by means of XRD, SEM, and TEM. The high symmetry and crystalline was revealed by high resolution transmission electronic microscope (HRTEM) and selected area electron diffraction (SAED). The growth mechanism of Ti 3SiC 2 crystals controlled by two-dimensional nucleation was put forward. The growth pattern of layered steps implies that the growth of the (0 0 2) face should undergo two steps, the intermittent two-dimensional nucleation and the continuous lateral spreading of layers on growth faces.

  18. Pyrochlore-structured titanate ceramics for immobilisation of actinides: Hot isostatic pressing (HIPing) and stainless steel/waste form interactions

    NASA Astrophysics Data System (ADS)

    Zhang, Yingjie; Li, Huijun; Moricca, Sam

    2008-07-01

    A pyrochlore-structured titanate ceramic has been studied in respect of its overall feasibility for immobilisation of impure actinide-rich radioactive wastes through the hot isostatic pressing (HIPing) technique. The resultant waste form contains mainly pyrochlore (˜70%), rutile (˜14%) as well as perovskite (˜12%), hollandite (˜2%) and brannerite (˜1%). Optical spectroscopy confirms that uranium (used to simulate Pu) exists mainly in the stable pyrochlore-structured phase as tetravalent ions as designed. The stainless steel/waste form interactions under HIPing conditions (1280 °C/100 MPa/3 h) do not seem to change the actinide-bearing phases and therefore should have no detrimental effect on the waste form.

  19. Ballistic Testing and High-Strain-Rate Properties of Hot Isostatically Pressed Ti-6Al-4V

    NASA Astrophysics Data System (ADS)

    Gu, Yabei; Indrakanti, Sastry S.; Nesterenko, Vitali F.

    2001-06-01

    Good ballistic performance with long rod, conical and flat projectiles (velocity range 0.4 - 1km/s) of hot isostatically pressed (HIPed) Ti-6Al-4V powder based targets (including composites) was demonstrated in our previous work. Compared to baseline material (MIL-T-9047G), new features such as different shape of craters in long rod penetration tests, etc were observed. In addition, there is a large spread of the plug velocities of HIPed materials in some flat projectile penetration experiments. The results of compression Hopkinson bar tests, final strain controlled and hat-shaped specimen tests on material cut from impacted targets will be presented to establish relations between ballistic performance and high strain rate properties of HIPed materials. The different microstructures of shear induced fracture surfaces in samples with different ballistic performance will be discussed to explore the correlation between ballistic properties and fracture behavior.

  20. An infrared pyroelectric detector improved by cool isostatic pressing with cup-shaped PZT thick film on silicon substrate

    NASA Astrophysics Data System (ADS)

    Peng, Q. X.; Wu, C. G.; Luo, W. B.; Chen, C.; Cai, G. Q.; Sun, X. Y.; Qian, D. P.

    2013-11-01

    In this paper, we presented a new pyroelectric detector with back to back silicon cups and micro-bridge structure. The PZT thick film shaped in the front cup was directly deposited with designed pattern by electrophoresis deposition (EPD). Pt/Ti Metal film, which was fabricated by standard photolithography and lift-off technology, was sputtered to connect the top electrode and the bonding pad. The cold isostatic press (CIP) treatment could be applied to improve the pyroelectric properties of PZT thick film. The infrared (IR) properties the CIP-optimized detector were measured. The voltage responsivity (RV) was 4.5 × 102 V/W at 5.3 Hz, the specific detectivity (D*) was greater than 6.34 × 108 cm Hz1/2 W-1 (frequency > 110 Hz), and the thermal time constant was 51 ms, respectively.

  1. HVOF Spraying of Fe-Based MMC Coatings with In Situ Formation of Hard Particles by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Röttger, A.; Weber, S. L.; Theisen, W.; Rajasekaran, B.; Vaßen, R.

    2012-03-01

    Thick (2-3 mm) Fe-base coatings with admixed ferrotitanium (Fe30Ti70) were applied to austenitic steel by a high-velocity oxy-fuel process (HVOF). Hot-isostatic pressing (HIP) was carried out to the decrease porosity and to increase the material strength, wear resistance, and adhesive bond strength of the deposited coating to the substrate material. SEM and XRD investigations confirmed the formation of hard titanium carbide (TiC) particles during HIP treatment as a result of strong carbon diffusion out of the metal matrix and into the Fe30Ti70 particles. The mechanical and wear properties of the densified coatings were investigated by means of shear tests, hardness measurements, and abrasive wear tests. A comparison of the coatings in the as-sprayed and the HIPed state showed a large increase in the wear resistance due to in situ TiC formation.

  2. Experimental and Theoretical Investigations of Hot Isostatically Pressed-Produced Stainless Steel/High Alloy Tool Steel Compound Materials

    NASA Astrophysics Data System (ADS)

    Lindwall, Greta; Flyg, Jesper; Frisk, Karin; Sandberg, Odd

    2011-05-01

    Consolidation of tool steel powders and simultaneous joining to a stainless 316L steel are performed by hot isostatic pressing (HIP). Two tool steel grades are considered: a high vanadium alloyed carbon tool steel, and a high vanadium and chromium alloyed nitrogen tool steel. The boundary layer arising during diffusion bonding is in focus and, in particular, the diffusion of carbon and nitrogen over the joint. Measurements of the elemental concentration profiles and corrosion tests by the double loop-electrochemical potentiokinetic reactivation (DL-EPR) method are performed. Comparative calculations with the DICTRA software are performed and are found to be in agreement with the experimental results. It is found that the carbon tool steel grade has a more critical influence on the corrosion resistance of the stainless 316L steel in comparison to the nitrogen tool steel grade.

  3. Processing and characterization of nanocrystalline molybdenum disilicide (MoSi{sub 2}) consolidated by hot isostatic pressing (HIP)

    SciTech Connect

    Haji-Mahmood, M.S.

    1995-02-10

    This work studied the effect nanocrystalline processing may have on mechanical properties of MoSi{sub 2} and the ease with which MoSi{sub 2} powder can be processed into a bulk shape. (MoSi{sub 2} presently is limited by poor strength above 1000 C and brittleness below DBTT.) This work studied cold and hot isostatic pressing (CIP, HIP). The attrited, CIPed, and HIPed samples were characterized by chemical analysis, XRD, SEM, microhardness, optical microscopy, and quantitative metallography (porosity, density). Fracture toughness of the nanocrystalline MoSi{sub 2} was found to be a factor of two higher than conventional MoSi{sub 2} and the hardness of 1500 C-HIPed compacts were higher, as well. Modulus test showed the calculated elastic constants to be higher than the original Cerac material.

  4. Micro-analysis of SiC-Si 3N 4 ceramics made by hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Wang, Wenmin; Lu, Rongrong; Zhu, Jieqing; Shi, Jihong; Jiang, Dongliang

    1996-02-01

    SEM (Scanning Electron Microscopy) and micro-PEB (Proton Elastic Backscattering) were used to study a composite ceramic (Si 3N 4/SiC) layer generated on the surface of SiC by exposing SiC to an N 2 atmosphere at high temperatures (1850, 1950 and 2000°C) for different times of 0.5, 1, and 2 h, respectively. The thickness of the layers and the concentration of Si 3N 4 in the layers have been determined and correlated with the material properties, such as bending strength and fracture toughness, before and after the nitndation process. A remarkable improvement of the properties has been found to be related to the Si 3N 4 concentration in the nitndation layer. A model of N 2 diffusion in SiC under HIP (Hot Isostatic Pressing) is discussed.

  5. Electrical transport properties of dense bulk YBa 2Cu 4O 8 produced by hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Andersson, B. M.; Sundqvist, B.; Niska, J.; Loberg, B.; Easterling, K.

    1990-10-01

    Highly dense sintered YBa 2Cu 4O 8 has been produced by hot isostatic pressing (HIP). The electrical resistivity ϱ of this material has been measured as a function of temperature T and pressure ϱ in the range 40-650 K and 0-0.7 GPa. Both the temperature dependence and the pressure dependence of ϱ are found to be well described by a model based on the standard Bloch-Grüneisen theory. It is pointed out that ϱ is liner in T only under isobaric conditions, while ϱ is strongly nonlinear in all high- Tc superconductors under isochoric (constant volume) conditions. The critical current density of the material is 900 A/cm 2 at 4 K, while the resistivity is 630 μΩ cm at 294 K.

  6. Influence of surface treatment of yttria-stabilized tetragonal zirconia polycrystal with hot isostatic pressing on cyclic fatigue strength.

    PubMed

    Iijima, Toshihiko; Homma, Shinya; Sekine, Hideshi; Sasaki, Hodaka; Yajima, Yasutomo; Yoshinari, Masao

    2013-01-01

    Hot isostatic pressing processed yttria-stabilized tetragonal zirconia polycrystal (HIP Y-TZP) has the potential for application to implants due to its high mechanical performance. The aim of this study was to investigate the influence of surface treatment of HIP Y-TZP on cyclic fatigue strength. HIP Y-TZP specimens were subjected to different surface treatments. Biaxial flexural strength was determined by both static and cyclic fatigue testing. In the cyclic fatigue test, the load was applied at a frequency of 10 Hz for 10(6) cycles in distilled water at 37°C. The surface morphology, roughness, and crystal phase of the surfaces were also evaluated. The cyclic fatigue strength (888 MPa) of HIP Y-TZP with sandblasting and acid-etching was more than twice that of Y-TZP as specified in ISO 13356 for surgical implants (320 MPa), indicating the clinical potential of this material. PMID:23538763

  7. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    NASA Astrophysics Data System (ADS)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  8. Manufacture of low carbon astroloy turbine disk shapes by hot isostatic pressing. Volume 2, project 1

    NASA Technical Reports Server (NTRS)

    Eng, R. D.; Evans, D. J.

    1979-01-01

    The performance of a hot isotatic pressed disk installed in an experimental engine and exposed to realistic operating conditions in a 150-hour engine test and a 1000 cycle endurance test is documented. Post test analysis, based on visual, fluorescent penetrant and dimensional inspection, revealed no defects in the disk and indicated that the disk performed satisfactorily.

  9. Effect of sphered particles on the firing contraction of porcelain inlay processed by cold isostatic pressing.

    PubMed

    Konishi, Junko; Watari, Fumio; Kawamoto, Chiharu; Sano, Hidehiko

    2003-08-15

    The effect of the sphered particles on the contraction ratio of porcelain inlay processed by the cold isostatic pressure (CIP) method was investigated. The conventional lathe-cut porcelain powder was crushed to finer particles and the secondary particles with spherical shape by adding binders of acrylic resin, wax, and polyvinyl alcohol, respectively. Porcelain powder was molded as a disc-shaped green body in a refractory model and compressed at 200 MPa by CIP. From this green compact, the sintered porcelain was obtained by only one step of firing. The porcelain discs were then used for the measurements of contraction ratio, scanning microscopic observation, biaxial flexure strength, Vickers hardness, and density. Firing contraction was decreased to about 1% in the sphered particle groups, compared with 7% of the lathe-cut porcelain powder. Although biaxial flexure strength was about 85 MPa, which is lower than the 120 MPa of the control group, and the density was significantly decreased by about 10% from the 2.4 g/cm3 of the control substance, Vickers hardness, which ranged from 531 to 537, showed no significant differences among all of the groups. The CIP method could save labor in the process of making porcelain inlays, and sphered powders could contribute significantly to a decrease in the contraction ratio in the sintering process. PMID:12861607

  10. Hot isostatic pressing of silicon nitride Sisub3n4 containing zircon, or zirconia and silica

    NASA Technical Reports Server (NTRS)

    Somiya, S.; Yoshimura, M.; Suzuki, T.; Nishimura, H.

    1980-01-01

    A hydrothermal synthesis apparatus with a 10 KB cylinder was used to obtain a sintered body of silicon nitride. The sintering auxiliary agents used were zircon (ZrSiO4) and a mixture of zirconia (ZrO2) and silica (SiO2). Experiments were conducted with the amounts of ZrSi04 or ArO2 and SiO2 varying over a wide range and the results compared to discover the quantity of additive which produced sintering in silicon nitride by the hot pressing method.

  11. Thermal Shock and Ablation Behavior of Tungsten Nozzle Produced by Plasma Spray Forming and Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Wang, Y. M.; Xiong, X.; Zhao, Z. W.; Xie, L.; Min, X. B.; Yan, J. H.; Xia, G. M.; Zheng, F.

    2015-08-01

    Tungsten nozzle was produced by plasma spray forming (PSF, relative density of 86 ± 2%) followed by hot isostatic pressing (HIPing, 97 ± 2%) at 2000 °C and 180 MPa for 180 min. Scanning electron microscope, x-ray diffractometer, Archimedes method, Vickers hardness, and tensile tests have been employed to study microstructure, phase composition, density, micro-hardness, and mechanical properties of the parts. Resistance of thermal shock and ablation behavior of W nozzle were investigated by hot-firing test on solid rocket motor (SRM). Comparing with PSF nozzle, less damage was observed for HIPed sample after SRM test. Linear ablation rate of nozzle made by PSF was (0.120 ± 0.048) mm/s, while that after HIPing reduced to (0.0075 ± 0.0025) mm/s. Three types of ablation mechanisms including mechanical erosion, thermophysical erosion, and thermochemical ablation took place during hot-firing test. The order of degree of ablation was nozzle throat > convergence > dilation inside W nozzle.

  12. Properties of Porous TiNbZr Shape Memory Alloy Fabricated by Mechanical Alloying and Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Ma, L. W.; Chung, C. Y.; Tong, Y. X.; Zheng, Y. F.

    2011-07-01

    In the past decades, systematic researches have been focused on studying Ti-Nb-based SMAs by adding ternary elements, such as Mo, Sn, Zr, etc. However, only arc melting or induction melting methods, with subsequent hot or cold rolling, were used to fabricate these Ni-free SMAs. There is no work related to powder metallurgy and porous structures. This study focuses on the fabrication and characterization of porous Ti-22Nb-6Zr (at.%) shape memory alloys produced using elemental powders by means of mechanical alloying and hot isostatic pressing. It is found that the porous Ti-22Nb-6Zr alloys prepared by the HIP process exhibit a homogenous pore distribution with spherical pores, while the pores have irregular shape in the specimen prepared by conventional sintering. X-ray diffraction analysis showed that the solid solution-treated Ti-22Nb-6Zr alloy consists of both β phase and α″ martensite phase. Morphologies of martensite were observed. Finally, the porous Ti-22Nb-6Zr SMAs produced by both MA and HIP exhibit good mechanical properties, such as superior superelasticity, with maximum recoverable strain of ~3% and high compressive strength.

  13. The use of isostatic pressing to improve the strength of TLP diffusion bonds in aluminium-based composites

    SciTech Connect

    Shirzadi, A.A.; Wallach, E.R.

    1996-12-31

    Transient Liquid Phase (TLP) diffusion bonding of aluminium-SiC composites, using copper interlayers, was carried out under low bonding pressure to minimize plastic deformation. This was followed by solid-state diffusion bonding under relatively high pressure as a complementary process to improve joint strength and reliability. In the high pressure stage, plastic deformation was avoided by lateral constraint of the sample in order to build up a hydrostatic stress state, simulating hot isostatic pressing (hipping). The bonding temperature in a TLP process is usually determined by the temperature at which the liquid phase forms, e.g., the Al-Cu eutectic formation temperature in this case. In theory, it should be possible to vary the applied pressure in order to optimize bonding. However, the superplastic behavior of the material used in this work led to excessive deformation at the bonding temperature, with consequent restrictions on the bonding pressure and on the resulting bond strengths. The subsequent use of higher bonding pressures with minimal plastic deformation in the second stage of the process resulted in considerable improvements in bond strength. Bonds with shear strengths as high as 70% and 92% respectively of the shear strengths of two aluminium composites, 8090 Al/SiC and 359 Al/SiC (given the same thermal cycles including post solution treatment and ageing), have been achieved.

  14. Effect of cold isostatic pressing on the transport current of filamentary MgB2 wire made by the IMD process

    NASA Astrophysics Data System (ADS)

    Kováč, P.; Hušek, I.; Pachla, W.; Melišek, T.; Kulich, M.; Rosová, A.; Kopera, L.

    2016-07-01

    This work describes the effect of cold isostatic pressing applied to as-drawn filamentary wires in a GlidCop and/or Cu sheath made by the internal magnesium diffusion process. Critical currents of as-drawn and isostatically pressed wires at high pressures up to 2.0 GPa followed by heat treatment at 640 °C for 40 min were measured. The obtained results show an improvement in boron powder density resulting in an increase of the critical current of MgB2 layers. The engineering current density increases by 4–13 times after the high-pressure treatment, and is influenced by the density of the boron powder and by the mechanical strength of the outer sheath.

  15. Tensile properties from room temperature to 1315 C of tungsten-lined tantalum-alloy (T-111) tubing fabricated by hot isostatic pressing

    NASA Technical Reports Server (NTRS)

    Buzzard, R. J.; Metroka, R. R.

    1974-01-01

    The effects were studied of a thin tungsten liner on the tensile properties of T-111 tubing considered for fuel cladding in a space power nuclear reactor concept. The results indicate that the metallurgically bonded liner had no appreciable effects on the properties of the T-111 tubing. A hot isostatic pressing method used to apply the liners is described along with a means for overcoming the possible embrittling effects of hydrogen contamination.

  16. Phase Transformation Behavior of Hot Isostatically Pressed NiTi-X (X = Ag, Nb, W) Alloys for Functional Engineering Applications

    NASA Astrophysics Data System (ADS)

    Bitzer, M.; Bram, M.; Buchkremer, H. P.; Stöver, D.

    2012-12-01

    Owing to their unique properties, NiTi-based shape memory alloys (SMAs) are highly attractive candidates for a lot of functional engineering applications like biomedical implants (stents), actuators, or coupling elements. Adding a third element is an effective measure to adjust or stabilize the phase transformation behavior to a certain extent. In this context, addition of alloying elements, which are low soluble or almost insoluble in the NiTi matrix is a promising approach and—with the exception of adding Nb—has rarely been reported in the literature so far, especially if the manufacturing of the net-shaped parts of these alloys is aspired. In the case of addition of elemental Nb, broadening of hysteresis between austenitic and martensitic phase transformation temperatures after plastic deformation of the Nb phase is a well-known effect, which is the key of function of coupling elements already established on the market. In the present study, we replaced Nb with additions of elemental Ag and W, both of which are almost insoluble in the NiTi matrix. Compared with Nb, Ag is characterized by higher ductility in combination with lower melting point, enabling liquid phase sintering already at moderate temperatures. Vice versa, addition of W might act in opposite manner considering its inherent brittleness combined with high melting temperature. In the present study, hot isostatic pressing was used for manufacturing such alloys starting from prealloyed NiTi powder and with the additions of Nb, Ag, and W as elemental powders. Microstructures, interdiffusion phenomena, phase transformation behaviors, and impurity contents were investigated aiming to better understand the influence of insoluble phases on bulk properties of NiTi SMAs.

  17. Tensile creep behavior and cyclic fatigue/creep interaction of hot- isostatically pressed Si sub 3 N sub 4

    SciTech Connect

    Liu, K.C.; Pih, H.; Stevens, C.O.; Brinkman, C.R.

    1991-01-01

    Tensile creep data are reported for a high-performance grade of hot isostatically pressed Si{sub 3}N{sub 4} that is currently being investigated as a candidate material for advanced heat engine applications. Specimens were tested in pure uniaxial tension at temperatures ranging from 1200 to 1370{degree}C. Creep strain was measured with an optical strain extensometer until creep rupture occurred, in some cases for periods in excess of 2000 h. To study the effects of various preloading material histories on creep behavior, specimens were prepared and tested in several conditions, i.e., unannealed, annealed, or precycled. Test results show that either treatment by thermal annealing or by precycling at 1370{degree}C can dramatically modify the initial transient creep behavior and enhance the resistance to creep deformation and hence the creep-rupture lifetime. However, the influence of the preloading histories on creep rate was diminished by high temperature exposure after about 500 h of testing. The rupture lifetime of the precycled specimen at 1370{degree}C was significantly higher than those of the unannealed and annealed specimens. In contrast, no significant extension of the creep-rupture lifetime was observed for a precycled specimen tested at 1300{degree}C. Steady-state creep was absent in some cases under certain conditions of temperature, stress, and heat treatment. Little or no tertiary creep was usually detected before specimen fracture occurred. The steady-state creep rate of this material was found to be a function of applied stress, temperature, and possibly the level of crystallinity in the intergranular phase. 9 refs., 15 figs.

  18. MICROSCOPY CHARACTERIZATION OF U-MO BEARING MINI-PLATES FABRICATED BY HOT ISOSTATIC PRESSING (HIPPING) WITH A LONG THERMAL CYCLE

    SciTech Connect

    Jan-Fong Jue

    2007-07-01

    The RERTR Program has formed the Production Development Team to coordinate fabrication efforts to produce the fuel elements for the qualifying irradiation tests. These fuel elements will be fabricated in production facilities. Fabrication development data will be shared with all participants on the development team. The INL has been developing a method of cladding using a Hot Isostatic Press (HIP). The operating parameters were varied to understand the impact of time, pressure and temperature on the reaction between the fuel and the cladding. This report details some of the data produced to date.

  19. On the Interface Generated by Hot Isostatic Pressing Compaction Process Between an AISI 304 Container and the Ti6Al4V Powders

    NASA Astrophysics Data System (ADS)

    Scherillo, Fabio; Aprea, Paolo; Astarita, Antonello; Scherillo, Antonella; Testani, Claudio; Squillace, Antonino

    2015-06-01

    In this work, the interface between a Ti6Al4V component made by Hot Isostatic Pressing and the AISI 304 container was studied in detail. The interface is dominated by interdiffusion with evident Kirkendall effect. Different intermetallic phases have been recognized. In particular, on the AISI 304 side of the interface, both χ and σ phases have been identified, whereas on the Ti6Al4V side λ phase (Laves), FeTi, (Fe,Ni)Ti, Ti2Ni, and β-Ti are present.

  20. On the recovery of the physical and mechanical properties of a CuCrZr alloy subjected to heat treatments simulating the thermal cycle of hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Holzwarth, U.; Pisoni, M.; Scholz, R.; Stamm, H.; Volcan, A.

    2000-03-01

    Due to their high mechanical strength and thermal conductivity precipitation hardened CuCrZr alloys are being considered as potential heat sink material for the ITER divertor vertical target. The fabrication of the divertor component involves a joining procedure by hot isostatic pressing (HIP). The impact of this method on the degradation of the physical and mechanical properties of the CuCrZr alloy and their possible subsequent recovery by (re-)aging heat treatments have been investigated by hardness measurements, tensile testing and measurements of thermal diffusivity and electrical resistivity. The thermal cycle of hot isostatic pressing has been simulated by solution annealing finished by cooling rates between 0.03 and 1.5 K s-1. The experiments revealed that a successful recovery of the desired mechanical strength is only achievable if cooling rates of about 1 K s-1 or higher can be realized after HIP. Otherwise the alloy becomes already over-aged during slow cooling after the joining procedure.

  1. Synroc-D Type Ceramics Produced by Hot Isostatic Pressing and Cold Crucible Melting for Immobilisation of (Al, U) Rich Nuclear Waste

    SciTech Connect

    Vance, Eric R.; La Robina, Michael; Li, Huijun; Davis, Joel

    2007-07-01

    A synroc-D ceramic consisting mostly of spinel, hollandite, pyrochlore-structured CaUTi{sub 2}O{sub 7}, UO{sub 2}, and Ti-rich regions shows promise for immobilisation of a HLW containing mainly Al and U, together with fission products. Ceramics with virtually zero porosities and waste loadings of 50-60 wt% on an oxide basis were prepared by cold crucible melting (CCM) at {approx}1500 deg. C, and also by subsolidus hot isostatic pressing (HIP) at 1100 deg. C to prevent volatile losses. PCT leaching test values for Cs were < 13 g/L, with all other normalised elemental extractions being well below 1 g/L. (authors)

  2. Significant Improvement of Mechanical Properties in NiAl-Cr(Mo)/Hf Alloy by Suction Casting and Subsequent Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Guo, J. T.; Huai, K. W.; Li, H. T.

    2007-01-01

    The NiAl-28Cr-5.5Mo-0.5Hf eutectic alloy was prepared by the suction casting (SC) technique and subsequent hot isostatic pressing (HIP) treatment, and tested for compressive strength and fracture behavior in the temperature range of 300 to 1373 K. The microstructure of suction-cast alloy is characterized by fine interlamellar spacing, large area fraction of eutectic cell, and fine Heusler (Ni2AlHf) phase distributed semicontinuously at the cell boundaries. After HIP treatment, Ni2AlHf phase at the cell boundaries is transformed into Hf solid solution phase and distributed homogeneously within the NiAl matrix. Compared with the conventionally cast alloy, the room-temperature compressive strain and elevated temperature strength of suction-cast alloy are enhanced markedly after HIP treatment. The reason is that the HIP treatment causes Hf solid solution phase to distribute homogeneously and then strengthens the NiAl matrix.

  3. High critical current densities reproducibly observed for hot-isostatic-pressed PbMo6S8 wires with Mo barriers

    NASA Astrophysics Data System (ADS)

    Yamasaki, H.; Umeda, M.; Kosaka, S.

    1992-08-01

    Fabrication process, critical current densities (Jc), and microstructure of the superconducting PbMo6S8 wires with Mo barriers have been investigated. Reducing the volume fraction of the Mo barrier and using electron-beam-melted Mo with less deformation resistance than that of conventional powder-metallurgy-processed Mo, facilitate the densification of PbMo6S8 and Jc improvement by the hot-isostatic-pressing (HIP) treatments. It was possible to obtain reproducibly HIP-treated PbMo6S8 wires with homogeneously high Jc not less than 10 exp 8 A/sq m at 22 T and 4.2 K, which is promising for the production of future high field (greater than 20 T) superconducting magnets.

  4. Comparative study: sensitization development in hot-isostatic-pressed cast and wrought structures type 316L(N)-IG stainless steel under isothermal heat treatment

    NASA Astrophysics Data System (ADS)

    Shutko, K. I.; Belous, V. N.

    2002-12-01

    This work focuses on the relative sensitization resistance of type 316L(N)-IG stainless steel (SS). Cast and wrought structures SS after solid hot-isostatic pressing (solid-HIP) operation are investigated under isothermal heat treatment. Wrought SS/SS solid-HIP joint sensitization is taken also into consideration. These experiments employed the quantitative double-loop electrochemical potentiokinetic reactivation (DL-EPR) and oxalic acid etch screening tests. A copper-copper sulfate-16% sulfuric acid test applied for strongly sensitized cast SS to reinforce the results were received by the methods mentioned above. Results from all employed methods correlate well. Sensitization was detected neither in cast nor in wrought SS in as-HIPed condition excluding wrought SS/SS solid-HIP joints. Significant difference between sensitization development rates was determined in cast and wrought SS structures when annealing at 675 °C for a duration up to 50 h.

  5. Effect of hot isostatic pressing on the structure and properties of cast polycrystalline gas-turbine blades made of nickel superalloys

    NASA Astrophysics Data System (ADS)

    Beresnev, A. G.

    2012-05-01

    A concept of a two-stage hot isostatic pressing (HIP) cycle is developed for castings made of nickel superalloys in order to minimize plastic deformation and the recrystallization ability of their structure. At the first stage of the cycle, diffusion pore dissolution is predominant due to the motion of vacancies toward grain boundaries in a polycrystal; at the second stage, retained coarse pores are filled during plastic deformation. The effect of uniform compression pressure during HIP and microstructure defects on the vacancy diffusion in nickel superalloys is estimated. A two-stage HIP regime is developed for processing of cast gas-turbine engine blades made of a ZhS6U alloy in order to substantially decrease the shrinkage porosity and to increase the high-temperature characteristics, including the creep and fatigue resistance.

  6. Understanding the Role of Hot Isostatic Pressing Parameters on the Microstructural Evolution of Ti-6Al-4V and Inconel 718 Fabricated by Electron Beam Melting

    SciTech Connect

    Peter, William H.; Nandwana, Peeyush; Kirka, Michael M.; Dehoff, Ryan R.; Sames, William; Erdman, III, Donald L.; Eklund, Anders; Howard, Ron

    2015-04-01

    In this project, Avure and ORNL evaluated the influence of hot isostatic pressing (HIP) and thermal cycling as standalone post processing techniques on the microstructure of electron beam powder bed deposited Ti-6Al-4V and Inconel 718 alloys. Electron beam powder bed deposition is an effective technology for fabricating complex net shape components that cannot be manufactured with conventional processes. However, material deposited by this technology results in columnar grain growth which is detrimental for many applications. For Ti-6Al-4V, it has been found that thermal cycling alone is not sufficient to breakdown the columnar microstructure that is typical of electron beam powder bed technology. HIP, on the other hand, has the potential to be an effective technique to break down the columnar microstructure of Ti-6Al-4V into a more equiaxed and refined β grain structure, and provide a more homogeneous microstructure compared to the thermally cycled samples. Overall, the project showed that hot isostatic pressing reduced/eliminated porosity in both Ti-6Al-4V and Inconel 718 However, based on the unique thermal cycle and the application of pressure in the HIP vessel, Ti-6Al-4V e-beam deposited microstructures were modified from columnar grain growth to equiaxed microstructures; a significant outcome to this collaboration. Inconel 718, on the other hand, shows no change in the macrostructure as a result of the current HIP cycle based on the thermal history, and would require further investigation. Though the results of HIP cycle were very good at changing the microstructure, further development in optimizing the post heat treatments and HIP cycles is required to improve mechanical properties.

  7. Hot-isostatic pressing of U-10Zr by grain boundary diffusion and creep cavitation. Part 2: Theory and data analysis

    SciTech Connect

    McDeavitt, S.M.; Solomon, A.A.

    1997-08-01

    Uranium-10 wt % zirconium (U-10Zr) is a fuel alloy that has been used in the Experimental Breeder Reactor-II (EBR-II). The high burnup that was desired in this fuel system made high demands on the mechanical compatibility between fuel and cladding both during normal operation and during safety-related transients when rapid differential expansion may cause high stresses. In general, this mechanical stress can be reduced by cladding deformation if the cladding is sufficiently ductile at high burnup, and/or by fuel hot-pressing. Fortunately, the fuel is very porous when it contacts the cladding, but this porosity gradually fills with solid fission products (primarily lanthanides) that may limit the fuel`s compressibility. If the porosity remains open, gaseous fission products are released and the porous fuel creeps rather than hot-presses under contact stresses. If the pores are closed by sintering or by solid fission products, the porous fuel will hot-isostatic press (HIP), as represented by the models to be discussed. HIP experiments performed at 700 C on U-10Zr samples with different impurity phase contents (Part 1) are analyzed in terms of several creep cavitation models. The coupled diffusion/creep cavitation model of Chen and Argon shows good quantitative agreement with measured HIP rates for hydride- and metal-derived U-10Zr materials, assuming that pores are uniformly distributed on grain boundaries and are of modal size, and that far-field strain rates are negligible. The analysis predicts, for the first time, an asymmetry between HIP and swelling at identical pressure-induced driving forces due to differences in grain boundary stresses. The differences in compressibility of hydride- and metal-derived U-10Zr can be partially explained by differences in pore size and spacing. The relevance of the experiments to description of in-reactor densification under external pressure or contact stress due to fuel/cladding mechanical interaction is discussed.

  8. Effects of long-time elevated temperature exposures on hot-isostatically-pressed power-metallurgy Udimet 700 alloys with reduced cobalt contents

    NASA Technical Reports Server (NTRS)

    Hart, F. H.

    1984-01-01

    Because almost the entire U.S. consumption of cobalt depends on imports, this metal has been designated "strategic'. The role and effectiveness of cobalt is being evaluated in commercial nickel-base superalloys. Udiment 700 type alloys in which the cobalt content was reduced from the normal 17% down to 12.7%, 8.5%, 4.3%, and 0% were prepared by standard powder metallurgy techniques and hot isostatically pressed into billets. Mechanical testing and microstructural investigations were performed. The mechanical properties of alloys with reduced cobalt contents which were heat-treated identically were equal or better than those of the standard alloy, except that creep rates tended to increase as cobalt was reduced. The effects of long time exposures at 760 C on mechanical properties and at 760 C and 845 C on microstructures were determined. Decreased tensile properties and shorter rupture lives with increased creep rates were observed in alloy modifications. The exposures caused gamma prime particle coarsening and formation of sigma phase in the alloys with higher cobalt contents. Exposure at 845 C also reduced the amount of MC carbides.

  9. Effect of Oxygen Content Upon the Microstructural and Mechanical Properties of Type 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Dhers, Jean; Sherry, Andrew H.

    2016-09-01

    Although hot isostatic pressing (HIP) has been shown to demonstrate significant advances over more conventional manufacture routes, it is important to appreciate and quantify the detrimental effects of oxygen involvement during the HIP manufacture process on the microstructural and material properties of the resulting component. This paper quantifies the effects of oxygen content on the microstructure and Charpy impact properties of HIP'd austenitic stainless steel, through combination of detailed metallographic examination and mechanical testing on HIP'd Type 316L steel containing different concentrations (100 to 190 ppm) of oxygen. Micron-scale pores were visible in the microstructure of the HIP'd materials postmetallographic preparation, which result from the removal of nonmetallic oxide inclusions during metallographic preparation. The area fraction of the resulting pores is shown to correlate with the oxygen concentration which influences the Charpy impact toughness over the temperature range of 77 K to 573 K (-196 °C to 300 °C), and demonstrates the influence of oxygen involved during the HIP manufacture process on Charpy toughness. The same test procedures and microstructural analyses were performed on commercially available forged 316L. This showed comparatively fewer inclusions and exhibited higher Charpy impact toughness over the tested temperature range.

  10. The Effect of Friction Stir Processing on the Mechanical Properties of Investment Cast and Hot Isostatically Pressed Ti-6Al-4V

    NASA Astrophysics Data System (ADS)

    Pilchak, A. L.; Williams, J. C.

    2011-06-01

    Friction-stir (FS) processing was used to modify the coarse, fully lamellar microstructure of investment cast and hot isostatically pressed (HIP'ed) Ti-6Al-4V. The effect of FS processing on mechanical properties was investigated using microtensile and four-point bend fatigue testing. The tensile results showed a typical microstructure dependence where yield strength and ultimate tensile strength both increased with decreasing slip length. Depending on the processing parameters, fatigue strength at 107 cycles was increased by 20 pct or 60 pct over that of the investment cast and HIP'ed base material. These improvements have been verified with a statistically significant number of tests. The results have been discussed in terms of the resistance of each microstructure fatigue crack initiation and small crack propagation. For comparison, a limited number of fatigue tests was performed on α + β forged Ti-6Al-4V with varying primary α volume fraction and also on investment cast material heat treated to produce a bi-lamellar condition.

  11. A Microstructural Study on the Observed Differences in Charpy Impact Behavior Between Hot Isostatically Pressed and Forged 304L and 316L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Bell, Andrew; Dhers, Jean; Sherry, Andrew H.

    2015-11-01

    With near-net shape technology becoming a more desirable route toward component manufacture due to its ability to reduce machining time and associated costs, it is important to demonstrate that components fabricated via Hot Isostatic Pressing (HIP) are able to perform to similar standards as those set by equivalent forged materials. This paper describes the results of a series of Charpy tests from HIP'd and forged 304L and 316L austenitic stainless steel, and assesses the differences in toughness values observed. The pre-test and post-test microstructures were examined to develop an understanding of the underlying reasons for the differences observed. The as-received microstructure of HIP'd material was found to contain micro-pores, which was not observed in the forged material. In tested specimens, martensite was detectable within close proximity to the fracture surface of Charpy specimens tested at 77 K (-196 °C), and not detected in locations remote from the fracture surface, nor was martensite observed in specimens tested at ambient temperatures. The results suggest that the observed changes in the Charpy toughness are most likely to arise due to differences in as-received microstructures of HIP'd vs forged stainless steel.

  12. Effect of Oxygen Content Upon the Microstructural and Mechanical Properties of Type 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Dhers, Jean; Sherry, Andrew H.

    2016-06-01

    Although hot isostatic pressing (HIP) has been shown to demonstrate significant advances over more conventional manufacture routes, it is important to appreciate and quantify the detrimental effects of oxygen involvement during the HIP manufacture process on the microstructural and material properties of the resulting component. This paper quantifies the effects of oxygen content on the microstructure and Charpy impact properties of HIP'd austenitic stainless steel, through combination of detailed metallographic examination and mechanical testing on HIP'd Type 316L steel containing different concentrations (100 to 190 ppm) of oxygen. Micron-scale pores were visible in the microstructure of the HIP'd materials postmetallographic preparation, which result from the removal of nonmetallic oxide inclusions during metallographic preparation. The area fraction of the resulting pores is shown to correlate with the oxygen concentration which influences the Charpy impact toughness over the temperature range of 77 K to 573 K (-196 °C to 300 °C), and demonstrates the influence of oxygen involved during the HIP manufacture process on Charpy toughness. The same test procedures and microstructural analyses were performed on commercially available forged 316L. This showed comparatively fewer inclusions and exhibited higher Charpy impact toughness over the tested temperature range.

  13. Hot isostatically-pressed aluminosilicate glass-ceramic with natural crystalline analogues for immobilizing the calcined high-level nuclear waste at the Idaho Chemical Processing Plant

    SciTech Connect

    Raman, S.

    1993-12-01

    The additives Si, Al, MgO, P{sub 2}O{sub 5} were mechanically blended with fluorinelsodium calcine in varying proportions. The batches were vacuum sealed in stainless steel canisters and hot isostatically pressed at 20,000 PSI and 1000 C for 4 hours. The resulting suite of glass-ceramic waste forms parallels the natural rocks in microstructural and compositional heterogeneity. Several crystalline phases ar analogous in composition and structure to naturally occurring minerals. Additional crystalline phases are zirconia and Ca-Mg borate. The glasses are enriched in silica and alumina. Approximately 7% calcine elements occur dissolved in this glass and the total glass content in the waste forms averages 20 wt%. The remainder of the calcine elements are partitioned into crystalline phases at 75 wt% calcine waste loading. The waste forms were tested for chemical durability in accordance with the MCC1-test procedure. The leach rates are a function of the relative proportions of additives and calcine, which in turn influence the composition and abundances of the glass and crystalline phases. The DOE leach rate criterion of less than 1 g/m{sup 2}-day is met by all the elements B, Cs and Na are increased by lowering the melt viscosity. This is related to increased crystallization or devitrification with increases in MgO addition. This exploratory work has shown that the increases in waste loading occur by preferred partitioning of the calcine components among crystalline and glass phases. The determination of optimum processing parameters in the form of additive concentration levels, homogeneous blending among the components, and pressure-temperature stabilities of phases must be continued to eliminate undesirable effects of chemical composition, microstructure and glass devitrification.

  14. Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

    SciTech Connect

    Y. Park; J. Yoo; K. Huang; D. D. Keiser, Jr.; J. F. Jue; B. Rabin; G. Moore; Y. H. Sohn

    2014-04-01

    Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45–345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr2 phase was observed to develop adjacent to Zr, and the a-U phase was found between the UZr2 and U10Mo, while the Mo2Zr was found as precipitates mostly within the a-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si)3Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the a-U, Mo2Zr, and UZr2 phases.

  15. Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

    NASA Astrophysics Data System (ADS)

    Park, Y.; Yoo, J.; Huang, K.; Keiser, D. D.; Jue, J. F.; Rabin, B.; Moore, G.; Sohn, Y. H.

    2014-04-01

    Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45-345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr2 phase was observed to develop adjacent to Zr, and the α-U phase was found between the UZr2 and U10Mo, while the Mo2Zr was found as precipitates mostly within the α-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si)3Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the α-U, Mo2Zr, and UZr2 phases.

  16. Thermoelectric power and resistivity of La1.8Sr0.2CaCu2O6-δ and the effects of O2 hot-isostatic-press annealing

    NASA Astrophysics Data System (ADS)

    Liu, C.-J.; Yamauchi, H.

    1995-05-01

    We have measured the resistivity and thermoelectric power of La1.8Sr0.2CaCu2O6-δ for 15<=T<=340 K. For the as-sintered sample heated under one atmosphere of oxygen, a minimum resistivity occurs at ca. 100 K, and the conductivity can be fitted to the form exp(T-1/2) or exp(T-1/4) for 30.3<=T<=86.8 K. The thermoelectric power varies as T1/2 for 20<=T<=200 K and exhibits a saturated value of ca. 100 μV/K for T>=230 K. Upon O2 HIP (hot isostatic press) treatment, the upturn of resistivity (metal- nonmetal transition) is suppressed and superconductivity ensues, and the thermoelectric power decreases in magnitude and displays a broad maximum at ca. 190 K in a manner similar to La2-xSrxCuO4-δ. It is conceivable that the O2 HIP treatment suppresses the metal-nonmetal transition as a result of increasing carrier concentration and possibly enhancing cation ordering. The possible origin of the metal-nonmetal transition is discussed.

  17. Influence of hot isostatic pressing on the structure and properties of an innovative low-alloy high-strength aluminum cast alloy based on the Al-Zn-Mg-Cu-Ni-Fe system

    NASA Astrophysics Data System (ADS)

    Akopyan, T. K.; Padalko, A. G.; Belov, N. A.

    2015-11-01

    Hot isostatic pressing (HIP) is applied for treatment of castings of innovative low-ally high-strength aluminum alloy, nikalin ATs6N0.5Zh based on the Al-Zn-Mg-Cu-Ni-Fe system. The influence of HIP on the structure and properties of castings is studied by means of three regimes of barometric treatment with different temperatures of isometric holding: t 1 = 505 ± 2°C, p 1 = 100 MPa, τ1 = 3 h (HIP1); t 2 = 525 ± 2°C, p 2 = 100 MPa, τ2 = 3 h (HIP2); and t 3 = 545 ± 2°C, p 3 = 100 MPa, τ3 = 3 h (HIP3). It is established that high-temperature HIP leads to actually complete elimination of porosity and additional improvement of the morphology of second phases. Improved structure after HIP provides improvement properties, especially of plasticity. In particular, after heat treatment according of regime HIP2 + T4 (T4 is natural aging), the alloy plasticity is improved by about two times in comparison with the initial state (from ~6 to 12%). While applying regime HIP3 + T6 (T6 is artificial aging for reaching the maximum strength), the plasticity has improved by more than three times in comparison with the initial state, as after treatment according to regimes HIP1 + T6 and HIP2 + T6 (from ~1.2 to ~5.0%), which are characterized by a lower HIP temperature.

  18. Microstructure and Mechanical Properties of Long Ti-6Al-4V Rods Additively Manufactured by Selective Electron Beam Melting Out of a Deep Powder Bed and the Effect of Subsequent Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Lu, S. L.; Tang, H. P.; Ning, Y. P.; Liu, N.; StJohn, D. H.; Qian, M.

    2015-09-01

    An array of eight long Ti-6Al-4V rods (diameter: 12 mm; height: 300 mm) have been additively manufactured, vertically and perpendicular to the powder bed, by selective electron beam melting (SEBM). The purpose was to identify and understand the challenges of fabricating Ti-6Al-4V samples or parts from a deep powder bed (more than 200-mm deep) by SEBM and the necessity of applying post heat treatment. The resulting microstructure and mechanical properties of these Ti-6Al-4V rods were characterized along their building ( i.e., axial) direction by dividing each rod into three segments (top, middle, and bottom), both before ( i.e., as-built) and after hot isostatic pressing (HIP). The as-built microstructure of each rod was inhomogeneous; it was coarsest in the top segment, which showed a near equilibrium α- β lamellar structure, and finest in the bottom segment, which featured a non-equilibrium mixed structure. The tensile properties varied along the rod axis, especially the ductility, but all tensile properties met the requirements specified by ASTM F3001-14. HIP increased the relative density from 99.03 pct of the theoretical density (TD) to 99.90 pct TD and homogenized the microstructure thereby leading to highly consistent tensile properties along the rod axis. The temperature of the stainless steel substrate used in the powder bed was monitored. The as-built inhomogeneous microstructure is attributed to the temperature gradient in the deep powder bed. Post heat treatment is thus necessary for Ti-6Al-4V samples or parts manufactured from a deep powder bed by SEBM. This differs from the additive manufacturing of small samples or parts from a shallow powder bed (less than 100-mm deep) by SEBM.

  19. On isostatic geoid anomalies

    NASA Technical Reports Server (NTRS)

    Haxby, W. F.; Turcotte, D. L.

    1978-01-01

    In regions of slowly varying lateral density changes, the gravity and geoid anomalies may be expressed as power series expansions in topography. Geoid anomalies in isostatically compensated regions can be directly related to the local dipole moment of the density-depth distribution. This relationship is used to obtain theoretical geoid anomalies for different models of isostatic compensation. The classical Pratt and Airy models give geoid height-elevation relationships differing in functional form but predicting geoid anomalies of comparable magnitude. The thermal cooling model explaining ocean floor subsidence away from mid-ocean ridges predicts a linear age-geoid height relationship of 0.16 m/m.y. Geos 3 altimetry profiles were examined to test these theoretical relationships. A profile over the mid-Atlantic ridge is closely matched by the geoid curve derived from the thermal cooling model. The observed geoid anomaly over the Atlantic margin of North America can be explained by Airy compensation. The relation between geoid anomaly and bathymetry across the Bermuda Swell is consistent with Pratt compensation with a 100-km depth of compensation.

  20. Comparison of various isostatic marine gravity disturbances

    NASA Astrophysics Data System (ADS)

    Tenzer, Robert; Bagherbandi, Mohammad; Sjöberg, Lars E.

    2015-08-01

    We present and compare four types of the isostatic gravity disturbances compiled at sea level over the world oceans and marginal seas. These isostatic gravity disturbances are computed by applying the Airy-Heiskanen (AH), Pratt-Hayford (PH) and Vening Meinesz-Moritz (VMM) isostatic models. In addition, we compute the complete crust-stripped (CCS) isostatic gravity disturbances which are defined based on a principle of minimizing their spatial correlation with the Moho geometry. We demonstrate that each applied compensation scheme yields a distinctive spatial pattern in the resulting isostatic marine gravity field. The AH isostatic gravity disturbances provide the smoothest gravity field (by means of their standard deviation). The AH and VMM isostatic gravity disturbances have very similar spatial patterns due to the fact that the same isostatic principle is applied in both these definitions expect for assuming a local (in the former) instead of a global (in the latter) compensation mechanism. The PH isostatic gravity disturbances are highly spatially correlated with the ocean-floor relief. The CCS isostatic gravity disturbances reveal a signature of the ocean-floor spreading characterized by an increasing density of the oceanic lithosphere with age.

  1. Results of intermediate-scale hot isostatic press can experiments

    SciTech Connect

    Nelson, L.O.; Vinjamuri, K.

    1995-05-01

    Radioactive high-level waste (HLW) has been managed at the Idaho Chemical Processing Plant (ICPP) for a number of years. Since 1963, liquid HLW has been solidified into a granular solid (calcine). Presently, over 3,800 m{sup 3} of calcine is stored in partially-underground stainless steel bins. Four intermediate- scale HLW can tests (two 6-in OD {times} 12-in tall and two 4-in OD {times} 7-in tall) are described and compared to small-scale HIP can tests (1- to 3-in OD {times} 1- to 4.5-in tall). The intermediate-scale HIP cans were loaded with a 70/30 calcine/frit blend and HIPped at an off-site facility at 1050{degrees}C; and 20 ksi. The dimensions of two cans (4-in OD {times} 7-in tall) were monitored during the HIP cycle with eddy-current sensors. The sensor measurements indicated that can deformation occurs rapidly at 700{degrees}C; after which, there is little additional can shrinkage. HIP cans were subjected to a number of analyses including calculation of the overall packing efficiency (56 to 59%), measurement of glass-ceramic (3.0 to 3.2 g/cc), 14-day MCC-1 leach testing (total mass loss rates < 1 g/m{sup 2} day), and scanning electron microscopy (SEM). Based on these analyses, the glass-ceramic material produced in intermediate-scale cans is similar to material produced in small-scale cans. No major scale-up problems were indicated. Based on the packing efficiency observed in intermediate- and small-scale tests, the overall packing efficiency of production-scale (24-in OD {times} 36- to 190-in tall) cans would be approximately 64% for a pre-HIP right-circular cylinder geometry. An efficiency of 64% would represent a volume reduction factor of 2.5 over a candidate glass waste prepared at 33 wt% waste loading.

  2. An apparatus for studying scintillator properties at high isostatic pressures.

    PubMed

    Gaumé, R M; Lam, S; Gascón, M; Setyawan, W; Curtarolo, S; Feigelson, R S

    2013-01-01

    We describe the design and operation of a unique hydraulic press for the study of scintillator materials under isostatic pressure. This press, capable of developing a pressure of a gigapascal, consists of a large sample chamber pressurized by a two-stage hydraulic amplifier. The optical detection of the scintillation light emitted by the sample is performed, through a large aperture optical port, by a photodetector located outside the pressure vessel. In addition to providing essential pressure-dependent studies on the emission characteristics of radioluminescent materials, this apparatus is being developed to elucidate the mechanisms behind the recently observed dependency of light-yield nonproportionality on electronic band structure. The variation of the light output of a Tl:CsI crystal under 511-keV gamma excitation and hydrostatic pressure is given as an example. PMID:23387697

  3. An apparatus for studying scintillator properties at high isostatic pressures

    NASA Astrophysics Data System (ADS)

    Gaumé, R. M.; Lam, S.; Gascón, M.; Setyawan, W.; Curtarolo, S.; Feigelson, R. S.

    2013-01-01

    We describe the design and operation of a unique hydraulic press for the study of scintillator materials under isostatic pressure. This press, capable of developing a pressure of a gigapascal, consists of a large sample chamber pressurized by a two-stage hydraulic amplifier. The optical detection of the scintillation light emitted by the sample is performed, through a large aperture optical port, by a photodetector located outside the pressure vessel. In addition to providing essential pressure-dependent studies on the emission characteristics of radioluminescent materials, this apparatus is being developed to elucidate the mechanisms behind the recently observed dependency of light-yield nonproportionality on electronic band structure. The variation of the light output of a Tl:CsI crystal under 511-keV gamma excitation and hydrostatic pressure is given as an example.

  4. Isostatic controls on carbonate platform development

    SciTech Connect

    Aigner, T.; Doyle, M.; Lawrence, D.T.

    1987-05-01

    Although carbonate bodies represent a significant surface load on the lithosphere, isostatic effects have been little studied in carbonate systems. In addition to well-documented controls such as spatially varying growth potential, the isostatic response to carbonate platform loads can be an important control on a variety of large-scale patterns in carbonate platform evolution. (1) The bucket structure as the basic anatomy of carbonate platforms can be explained isostatically by load-induced sagging of platform interiors and upbulging of platform margins. (2) Pulses of rapid sea level rises may transform isostatically sagged platform interiors into partly drowned intra-platform basins surrounded by elevated rims. (3) Differential drowning of isostatically sagged platforms may cause a wide-spread megabank to evolve into an archipelago of isolated platforms and intervening troughs. This may be an alternative mechanism for the origin of isolated platforms in the Bahamas. (4) Isolated pinnacle reefs within carbonate/evaporite provinces that occur close to the shelf margin may be initiated in flexural bulges developing beyond the edges of the load of the carbonate shelf during a cycle of sea level fall and rise. Quantitative computer simulations of the isostatic control on carbonate platform development will be presented.

  5. Powder processing of nitrides (excluding hot isostatic processing). (Latest citations from Engineered Materials abstracts). Published Search

    SciTech Connect

    1996-02-01

    The bibliography contains citations concerning the properties and processing of metal nitride ceramics and refractories. Citations consider compacting and sintering processes. Phase transformations, crystallization, and devitrification processes are considered. Aluminum nitride, boron nitride, silicon nitride, silicon oxynitride, and titanium nitride are among materials discussed. The use of hot isostatic pressing is considered in a separate bibliography. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  6. Isostatic Model and Isostatic Gravity Anomalies of the Arabian Plate and Surroundings

    NASA Astrophysics Data System (ADS)

    Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

    2016-04-01

    The isostatic modeling represents one of the most useful "geological" reduction methods of the gravity field. With the isostatic correction, it is possible to remove a significant part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomalies. Although there exist several isostatic compensation schemes, it is usually supposed that a choice of the model is not an important factor to first order, since the total weight of compensating masses remains the same. We compare two alternative models for the Arabian plate and surrounding area. The Airy model gives very significant regional isostatic anomalies, which cannot be explained by the upper crust structure or disturbances of the isostatic equilibrium. Also, the predicted "isostatic" Moho is very different from existing seismic observations. The second isostatic model includes the Moho, which is based on seismic determinations. Additional compensation is provided by density variations within the lithosphere (chiefly in the upper mantle). According to this model, the upper mantle under the Arabian Shield is less dense than under the Platform. In the Arabian platform, the maximum density coincides with the Rub' al Khali, one of the richest oil basin in the world. This finding agrees with previous studies, showing that such basins are often underlain by dense mantle, possibly related to an eclogite layer that has caused their subsidence. The mantle density variations might be also a result of variations of the lithosphere thickness. With the combined isostatic model, it is possible to minimize regional anomalies over the Arabian plate. The residual local anomalies correspond well to tectonic structure of the plate. Still very significant anomalies, showing isostatic disturbances of the lithosphere, are associated with the Zagros fold belt, the collision zone of the Arabian and Eurasian plates.

  7. Drill Presses.

    ERIC Educational Resources Information Center

    Engelbrecht, Nancy; And Others

    These instructional materials provide an orientation to the drill press for use at the postsecondary level. The first of seven sections lists seven types of drill presses. The second section identifies 14 drill press parts. The third section lists 21 rules for safe use of drilling machines. The fourth section identifies the six procedures for…

  8. Anchored boundary conditions for locally isostatic networks

    NASA Astrophysics Data System (ADS)

    Theran, Louis; Nixon, Anthony; Ross, Elissa; Sadjadi, Mahdi; Servatius, Brigitte; Thorpe, M. F.

    2015-11-01

    Finite pieces of locally isostatic networks have a large number of floppy modes because of missing constraints at the surface. Here we show that by imposing suitable boundary conditions at the surface the network can be rendered effectively isostatic. We refer to these as anchored boundary conditions. An important example is formed by a two-dimensional network of corner sharing triangles, which is the focus of this paper. Another way of rendering such networks isostatic is by adding an external wire along which all unpinned vertices can slide (sliding boundary conditions). This approach also allows for the incorporation of boundaries associated with internal holes and complex sample geometries, which are illustrated with examples. The recent synthesis of bilayers of vitreous silica has provided impetus for this work. Experimental results from the imaging of finite pieces at the atomic level need such boundary conditions, if the observed structure is to be computer refined so that the interior atoms have the perception of being in an infinite isostatic environment.

  9. Isostatic models and isostatic gravity anomalies of the Arabian plate and surroundings

    NASA Astrophysics Data System (ADS)

    Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

    2015-04-01

    Isostaic anomalies represent one of the most useful "geological" reduction of the gravity field. With the isostatic correction it is possible to remove a significant part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomalies. This correction is based on the fact that a major part of the near-surface load is compensated by variations of the lithosphere boundaries (chiefly the Moho and LAB) and by density variations within the crust and upper mantle. It is usually supposed that it is less important to a first order, what is the actual compensation model when reducing the effect of compensating masses, since their total weight is exactly opposite to the near-surface load. We compare several compensating models for the Arabian plate and surrounding area. The Airy model gives very significant regional isostatic anomalies, which can not be explained by the upper crust structure or disturbances of the isostatic equilibrium. Also the predicted "isostatic" Moho is very different from the existing observations. The second group of the isostatic models includes the Moho, which is based on existing seismic determinations. Additional compensation is provided by density variations within the lithosphere (chiefly in the upper mantle). In this way we minimize regional anomalies over the Arabian plate. The residual local anomalies well correspond to tectonic structure of the plate. Still very significant anomalies are associated with the Zagros fold belt, the collision zone of the Arabian and Eurasian plates.

  10. Powder processing of nitrides (excluding hot isostatic processing). (Latest citations from Engineered Materials abstracts). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the properties and processing of metal nitride ceramics and refractories. Citations consider compacting and sintering processes. Phase transformations, crystallization, and devitrification processes are considered. Aluminum nitride, boron nitride, silicon nitride, silicon oxynitride, and titanium nitride are among materials discussed. The use of hot isostatic pressing is considered in a separate bibliography. (Contains 250 citations and includes a subject term index and title list.)

  11. The kinetics of dolomite reaction rim growth under isostatic and non-isostatic pressure conditions

    NASA Astrophysics Data System (ADS)

    Helpa, V.; Rybacki, E.; Morales, L. G.; Abart, R.; Dresen, G. H.

    2013-12-01

    During burial and exhumation, rocks are simultaneously exposed to metamorphic reactions and tectonic stresses. Therefore, the reaction rate of newly formed minerals may depend on chemical and mechanical driving forces. Here, we investigate the reaction kinetics of dolomite (CaMg[CO3]2) rim growth by solid-state reactions experiments on oriented calcite (CaCO3) and magnesite (MgCO3) single crystals under isostatic and non-isostatic pressure conditions. Cylindrical samples of 3-5 mm length and 7 mm diameter were drilled and polished perpendicular to the rhombohedral cleavage planes of natural clear crystals. The tests were performed using a Paterson-type deformation apparatus at P = 400 MPa confining pressure, temperatures, T, between 750 and 850°C, and reaction durations, t, of 2 - 146 h to calculate the kinetic parameters of dolomite rim growth under isostatic stress conditions. For non-isostatic reaction experiments we applied in addition differential stresses, σ, up to 40 MPa perpendicular to the contact interface at T = 750°C for 4 - 171 h duration, initiating minor inelastic deformation of calcite. The thickness of the resulting dolomite reaction rims increases linearly with the square root of time, indicating a diffusion-controlled reaction. The rims consist of two different textural domains. Granular dolomite grains (≈ 2 -5 μm grain size) form next to calcite and elongated palisade-shaped grains (1-6 μm diameter) grow perpendicular to the magnesite interface. Texture measurements with the electron backscatter diffraction technique indicate that the orientations of dolomite grains are mainly influenced by the orientation of the calcite educt crystal, in particular in the granular rim. To some extent, the texture of dolomite palisades is also influenced by the orientation of magnesite. The thickness of the two individual layers increases with temperature. At 400 MPa isostatic pressure, T = 750°C and t = 29 hours, a 5 μm thick granular dolomite layer

  12. Erosion, isostatic response, and the missing peneplains

    NASA Astrophysics Data System (ADS)

    Phillips, Jonathan D.

    2002-06-01

    The peneplain—a low-relief erosional plain worn to near base level—is a venerable concept in geomorphology, geology, and geography. Yet despite more than a century of effort, no convincing example of a contemporary peneplain has been identified, and the identification of relict peneplains is uncertain and controversial. As a peneplain is a logical outcome during a period of long tectonic stability, the paucity or absence of peneplains is problematic. Most explanations are based on the notion that the periods of tectonic stability required for peneplain formation are too long to allow the features to fully develop, or that Neogene tectonics has precluded recent peneplanation. This paper proposes an alternative explanation, generally consistent with those given above, which can also explain the absence of peneplains in regions experiencing long tectonic stability. If erosion or deposition rates are related to elevation and if isostatic response (uplift or subsidence) is related to erosional unloading or depositional loading, the relationship between these components is dynamically unstable. This is demonstrated mathematically. This instability implies that no particular state or mode of topographic evolution, including peneplanation, is likely to persist in the face of variations or perturbations that influence any system component. Thus, formation of a peneplain would require tectonic stability and also relative constancy in sea level (or rates and direction of sea level change), climate, biotic influences on erosion or deposition, and any other factors that modify erosion, deposition, elevation fields, or isostatic responses. This would explain an absence of geologically contemporary peneplains and a rarity of well-developed peneplains in the geologic record.

  13. Glacial isostatic uplift of the European Alps

    NASA Astrophysics Data System (ADS)

    Mey, Juergen; Scherler, Dirk; Wickert, Andrew D.; Egholm, David L.; Tesauro, Magdala; Schildgen, Taylor F.; Strecker, Manfred R.

    2016-04-01

    Present-day vertical movements of the Earth's surface are mostly due to tectonic deformation, volcanic processes, and crustal loading/unloading. In tectonically stable regions of North America and Scandinavia, vertical movements are almost entirely attributable to glacial isostatic rebound after the melting of the Laurentide and Fennoscandian ice sheets. In contrast, the Pleistocene Alpine icecap grew on a younger mountain belt that formed by collision of the European and African plates, still subject to shortening. Therefore, measured uplift is potentially a composite signal of tectonic shortening and unloading after deglaciation and concomitant erosion. Deciphering the contributions of tectonics and crustal unloading to present-day uplift rates in formerly-glaciated mountain belts is a prerequisite to using uplift data to estimate the viscosity structure of the Earth's mantle, a key variable in geodynamics. We evaluate the post-LGM glacial-isostatic rebound of the Alps following a 4-tiered procedure. First, we estimated the thickness distribution of sedimentary valley fills to create a bedrock map of the entire mountain belt. Second, this map was used as topographic basis for the reconstruction of the Alpine icecap using a numerical ice-flow model. Third, we estimated the equilibrium deflection of the Alpine lithosphere, using the combined loads of ice and sediments with a variable effective elastic thickness. Finally, we used an exponential decay function to infer the residual deflection and the present-day uplift rate for a range of upper mantle viscosities. Our analysis shows that virtually all of the geodetically measured surface uplift in the Swiss and the Austrian Alps can be attributed to glacial unloading and redistribution of sediments, assuming an upper-mantle viscosity lower than that inferred for an old craton (e.g., Fennoscandia), but higher than that for a region with recent crustal thinning (e.g., Basin and Range province).

  14. Adapting isostatic microbial growth parameters into non-isostatic models for use in dynamic ecosystems

    NASA Astrophysics Data System (ADS)

    Spangler, J.; Schulz, C. J.; Childers, G. W.

    2009-12-01

    Modeling microbial respiration and growth is an important tool for understanding many geochemical systems. The estimation of growth parameters relies on fitting experimental data to a selected model, such as the Monod equation or some variation, most often under batch or continuous culture conditions. While continuous culture conditions can be analogous to some natural environments, it often isn’t the case. More often, microorganisms are subject to fluctuating temperature, substrate concentrations, pH, water activity, and inhibitory compounds, to name a few. Microbial growth estimation under non-isothermal conditions has been possible through use of numerical solutions and has seen use in the field of food microbiology. In this study, numerical solutions were used to extend growth models under more non-isostatic conditions using momentary growth rate estimates. Using a model organism common in wastewater (Paracoccus denitrificans), growth and respiration rate parameters were estimated under varying static conditions (temperature, pH, electron donor/acceptor concentrations) and used to construct a non-isostatic growth model. After construction of the model, additional experiments were conducted to validate the model. These non-isostatic models hold the potential for allowing the prediction of cell biomass and respiration rates under a diverse array of conditions. By not restricting models to constant environmental conditions, the general applicability of the model can be greatly improved.

  15. Mechanical Properties from PBX 9501 Pressing Study

    NASA Astrophysics Data System (ADS)

    Graff Thompson, Darla; Wright, Walter J.

    2004-07-01

    A PBX 9501 pressing study was conducted by researchers in ESA-WMM, LANL, to identify the hydrostatic pressing parameters most important in fabricating high-density parts with uniform density. In this study, 31 charges were pressed using a full permutation of six pressing parameters. Five charges from the set of 31 were selected for an evaluation of their mechanical properties, specifically uniaxial compression and tension. Charges were selected to 1) span the density range of the study, and 2) allow two direct comparisons of pressing parameters independent of bulk density (density has a well-established affect on some material properties). Three PBX 9501 charges pressed isostatically at Pantex Plant in Amarillo, TX were also included in the study. The tensile properties of the 8 charges varied significantly. Careful evaluation of the results suggests that an increase in pressing temperature may correlate with an increase in tensile stress (strength) and a decrease in strain (ductility). Trends in compression exist but are less pronounced. In an effort to explore the relationship between pressing temperature and tensile strength, four sheets of Estane polymer (a component of the PBX 9501 binder) were compression molded at 70, 90, 110 and 130°C. The tensile strength of Estane was observed to increase by a factor of nearly 20 when the molding temperature was increased from 70 to 90°C (strength increase was negligible beyond 90°C). We present an outline of ongoing work that will irrefutably quantify the mechanical property affects of both pressing temperature and dwell time on PBX 9501.(LA-UR 03-4842).

  16. The isostatic state of Mead crater

    NASA Astrophysics Data System (ADS)

    Banerdt, W. B.; Konopliv, A. S.; Rappaport, N. J.; Sjogren, W. L.; Grimm, R. E.; Ford, P. G.

    1994-11-01

    We have analyzed high-resolution Magellan Doppler tracking data over Mead crater, using both line-of-sight and spherical harmonic methods, and have found a negative gravity anomaly of about 4-5 mgal (at spacecraft altitude, 182 km). This is consistent with no isostatic compensation of the present topography; the uncertainty in the analysis allows perhaps as much as 30% compensation at shallow depths (approximately 25 km). This is similar to observations of large craters on Earth, which are not generally compensated, but contrasts with at least some lunar basins which are inferred to have large Moho uplifts and corresponding positive Bouguer anomalies. An uncompensated load of this size requires a lithosphere with an effective elastic lithosphere thickness greater than 30 km. In order for the crust-mantle boundary not to have participated in the deformation associated with the collapse of the transient cavity during the creation of the crater, the yield strength near the top of the mantle must have been significantly higher on Earth and Venus than on the Moon at the time of basin formation. This might be due to increased strength against frictional sliding at the higher confining pressures within the larger planets. Alternatively, the thinner crusts of Earth and Venus compared to that of the Moon may result in higher creep strength of the upper mantle at shallower depths.

  17. Numerical simulation of Glacial Isostatic Adjustment

    NASA Astrophysics Data System (ADS)

    Miglio, E.

    2015-12-01

    In the Earth's crust, stress can be subdivided into tectonic background stress, overburden pressure, and pore-fluid pressure. The superposition of the first two and the variation of the third part are key factors in controlling movement along faults. Furthermore, stresses due to sedimentation and erosion contribute to the total stress field. In deglaciated regions, an additional stress must be considered: the rebound stress, which is related to rebounding of the crust and mantle after deglaciation. During the growth of a continental ice sheet, the lithosphere under the iceload is deformed and the removal of the ice load during deglaciation initiates a rebound process. The uplift is well known in formerly glaciated areas, e.g.North America and Scandinavia, and in currently deglaciating areas, e.g.Alaska, Antarctica, and Greenland. The whole process of subsiding and uplifting during the growth and melting of an iceload and all related phenomena is known as glacial isostatic adjustment. During the process of glaciation, the surface of the lithosphere is depressed underneath the ice load and compressional flexural stresses are induced in the upper lithosphere, whereas the bottom of the lithosphere experiences extensional flexural stresses; an additional vertical stress due to the ice load is present and it decreases to zero during deglaciation. During rebound, flexural stresses relax slowly. These stresses are able to change the original stress directions and regime.In this work we aim to study the effect of the GIA process in the context of petroleum engineering. The main aspect we will focus on is the mathematical and numerical modeling of the GIA including thermal effects. We plan also to include a preliminary study of the effect of the glacial erosion. All these phenomena are of paramount importance in petroleum engineering: for example some reservoir have been depleted due to tilting caused by both GIA, erosion and thermal effects.

  18. Isostatic compensation of equatorial highlands on Venus

    NASA Technical Reports Server (NTRS)

    Kucinskas, Algis B.; Turcotte, Donald L.

    1994-01-01

    Spherical harmonic models for Venus' global topography and gravity incorporating Magellan data are used to test isostatic compensation models in five 30 deg x 30 deg regions representative of the main classes of equatorial highlands. The power spectral density for the harmonic models obeys a power-law scaling with spectral slope Beta approximately 2 (Brown noise) for the topography and Beta approximately 3 (Kaula's law) for the geoid, similar to what is observed for Earth. The Venus topography spectrum has lower amplitudes than Earth's which reflects the dominant lowland topography on Venus. Observed degree geoid to topography ratios (GTRs) on Venus are significantly smaller than degree GTRs for uncompensated topography, indicative of substantial compensation. Assuming a global Airy compensation, most of the topography is compensated at depths greater than 100 km, suggesting a thick lithosphere on Venus. For each region considered we obtain a regional degree of compensation C from a linear regression of Bouguer anomaly versus Bouguer gravity data. Geoid anomaly (N) versus topography variation (h) data for each sample were compared, in the least-squares sense, to theoretical correlations for Pratt, Airy, and thermal thinning isostasy models yielding regional GTR, zero-elevation crustal thickness (H), and zero elevation thermal lithosphere thickness (y(sub L(sub 0)), respectively. We find the regional compensation to be substantial (C approximately 52-80%), and the h, N data correlations in the chosen areas can be explained by isostasy models applicable on the Earth and involving variations in crustal thickness (Airy) and/or lithospheric (thermal thinning) thickness. However, a thick crust and lithosphere (y(sub L(sub 0)) approximately 300 km) must be assumed for Venus.

  19. Development of toughened Si/sub 3/N/sub 4/ composites by glass encapsulated hot isostatic pressure: Final report

    SciTech Connect

    Corbin, N.D.; Willkins, C.A.

    1988-08-01

    This one-year program was to develop fully dense Si/sub 3/N/sub 4/ matrix SiC whisker composites with enhanced properties over monolithic Si/sub 3/N/sub 4/ materials. Composites were prepared by a Reaction Bonded Silicon Nitride (RBSN) approach followed by Hot Isostatic Pressing (HIPing). The emphasis of this study was to determine the role of whisker aspect ratio, coatings on whiskers, nitridation environments and HIP parameters on composite properties. The ASEA HIP process which has the potential for producing near-net shaped complex geometries was used throughout this program. 26 refs., 22 figs., 7 tabs.

  20. Press Start

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    This level sets the stage for the design philosophy called “Triadic Game Design” (TGD). This design philosophy can be summarized with the following sentence: it takes two to tango, but it takes three to design a meaningful game or a game with a purpose. Before the philosophy is further explained, this level will first delve into what is meant by a meaningful game or a game with a purpose. Many terms and definitions have seen the light and in this book I will specifically orient at digital games that aim to have an effect beyond the context of the game itself. Subsequently, a historical overview is given of the usage of games with a serious purpose which starts from the moment we human beings started to walk on our feet till our contemporary society. It turns out that we have been using games for all kinds of non-entertainment purposes for already quite a long time. With this introductory material in the back of our minds, I will explain the concept of TGD by means of a puzzle. After that, the protagonist of this book, the game Levee Patroller, is introduced. Based on the development of this game, the idea of TGD, which stresses to balance three different worlds, the worlds of Reality, Meaning, and Play, came into being. Interested? Then I suggest to quickly “press start!”

  1. Structural Behavior of Monolithic Fuel Plates During Hot Isostatic Pressing and Annealing

    SciTech Connect

    Pavel G. Medvedev; Hakan Ozaltun

    2010-03-01

    This paper presents results of the stress analysis in the monolithic fuel plates during thermal transients performed using COMSOL finite element analysis software. Large difference in the thermal expansion between the U-Mo foil and Al cladding is the main load origin during heating and cooling of the fuel plates. In addition, the mechanical behavior of the plate is affected by the difference in yield points between the foil and the cladding. This is manifested by the plastic deformation and permanent strains in the cladding, and elastic deformation of the foil. The results show existence of the critical temperature points at which the stresses change from compressive to tensile. The paper highlights principal differences in mechanical behavior between monolithic and dispersion fuel plates, underlines the need for mechanical property data, especially for the U-Mo alloys, and discusses the methodology for mechanical analysis of the monolithic plates.

  2. Characterisation of stainless steel synroc interactions under hot isostatic pressing (HIPing) conditions

    NASA Astrophysics Data System (ADS)

    Li, H.; Zhang, Y.; McGlinn, P. J.; Moricca, S.; Begg, B. D.; Vance, E. R.

    2006-09-01

    Stainless steel/synroc interactions under HIPing conditions (1280 °C/100 MPa/3 h) have been studied. The synroc material was based on the zirconolite-rich ceramic targeted for surplus Pu disposition. A ˜300 mm-thick complex reaction interface with 8 distinct layers has been identified. Although the Fe diffusion controlled interactions have changed the microstructures of the synroc phases at the interface, they do not affect the integrity of synroc and are unlikely to have any detrimental effect on this synroc derivative.

  3. Development of a high strength hot isostatically pressed /HIP/ disk alloy, MERL 76

    NASA Technical Reports Server (NTRS)

    Evans, D. J.; Eng, R. D.

    1980-01-01

    A nickel-based powder metal disk alloy developed for use in advanced commercial gas turbines is described. Consideration is given to final alloy chemistry modifications made to achieve a desirable balance between tensile strength and stress rupture life and ductility. The effects of post-consolidation heat treatment are discussed, the preliminary mechanical properties obtained from full-scale turbine disks are presented.

  4. Synthesis of increased-density bismuth-based superconductors with cold isostatic pressing and heat treating

    DOEpatents

    Lanagan, Michael T.; Picciolo, John J.; Dorris, Stephen E.

    1997-01-01

    The present invention is directed to a process for producing high temperature superconducting ceramic materials. More particularly, the present invention is directed to a process that enhances the densification of Bi.sub.1.8 Pb.sub.0.4 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 "BSCCO" ceramics.

  5. Characterization of porosity of isostatically pressed and sintered nickel-base powdered metal.

    PubMed

    Fuys, R A; Craig, R G; Asgar, K

    1976-07-01

    Characterization of the pore structure of compacted and sintered parts made from a nickel-base powder was accomplished using the mercury porosimetry method. The theoretical density values for the sintered specimens varied from 56.3 to 96.7% which corresponds to a porosity of 43.7 to 3.3%. A maximum interconnecting median pore diameter of 21 mum resulted from a -80/+200 mesh powder compacted at 138 MN/m2 and sintered for 2 h at 1250 degrees C. Photomicrographs of the same sample showed that it had a maximum pore diameter of 200 mum. The interconnected pore volume decreased with decreasing particle size of the powder, increasing compaction pressure, and increasing sintering temperature. Mechanical properties of tensile strength, yield strength, elastic modulus and percentage elongation were correlated with the pore structure. Proper selection of particle size, compaction pressure, sintering times and sintering temperatures should permit parts with controlled porosity characteristics to be produced that possess adequate mechanical properties for application as implants. PMID:1068234

  6. Hot isostatically pressed manufacture of high strength MERL 76 disk and seal shapes

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1982-01-01

    The performance of a HIP MERL 76 disk installed in an experimental engine and exposed to realistic operating conditions in a 150 hour, 1500 cycle endurance test is examined. Post test analysis, based on visual, fluorescence penetrant and dimensional inspection, indicates that the disk performs satisfactorily.

  7. Thermal and stress analysis of hot isostatically pressed, alumina ceramic, nuclear waste containers

    SciTech Connect

    Chang, Yun; Hoenig, C.L.

    1990-03-01

    The Yucca Mountain Project is studying design and fabrication options for a safe durable container in which to store nuclear waste underground at Yucca Mountain, Nevada. The ceramic container discussed here is an alternative to using a metal container. This ceramic alternative would be selected if site conditions prove too corrosive to use metals for nuclear waste storage. Some of the engineering problems addressed in this study were: the stress generated in the alumina container by compressive loads when 4000 to 40,000 psi of external pressure is applied; the thermal stress in the container during the heating and cooling processes; the temperature histories of the container in various production scenarios and the power required for typical heaters; the fastest possible turnaround time to heat, seal, and cool the container commensurate with preserving the structural integrity of the ceramic and the closure; the testing of some commercial heating elements to determine the maximum available heat output; and the trade-offs between the minimization in thermal stress and cycle time for closure. 2 refs., 23 figs., 2 tabs.

  8. Isostatic diffusion bonding of IN-718SPF sheet

    SciTech Connect

    McKimpson, M.G.; Campbell, J.R.

    1996-12-31

    Isostatic diffusion bonding represents a potentially attractive technique for joining superplastically-formable nickel-base alloys such as Inconel alloy 718SPF sheet. Isostatic diffusion bonding trials have been carried out on Inconel alloy 718SPF/Inconel alloy 718SPF couples at temperatures ranging from 950 C (1,750 F) to 1,150 C (2,100 F) and isostatic pressures ranging up to 415 MPa (60,000 psi). Materials bonded at 1,150 C and 414 MPa exhibited room temperature shear strengths nearly comparable to those of the parent metal, but also showed substantial grain growth in the base metal away from the bond plane. Materials bonded at lower temperatures exhibited similar strengths with substantially less grain coarsening. Metallographic and mechanical testing results obtained on these diffusion bonded Inconel alloy 718SPF materials are presented and compared with existing diffusion bonding models.

  9. The complex isostatic equilibration of Australia's deep crust.

    NASA Astrophysics Data System (ADS)

    Aitken, Alan; Gross, Lutz; Altinay, Cihan

    2016-04-01

    A recent study, using a new finite-element based gravity inversion method has modelled in high-resolution the density and pressure fields for the Australian continent. Here we analyse the pressure results to consider how Australia's lower-crust and Moho contribute to the isostatic equilibration of topography and crustal masses. We find that the situation is more complex than the commonly applied model of isostatic compensation through crustal thickness variations. Key differences include low pressure-variability at ca. 30-35 km, suggesting that the thickness of the felsic-intermediate crust equilibrates most of the upper-crustal loads; increasing pressure-variability between 30-50 km, suggesting that positively buoyant deep-crustal roots generate disequilibrium. These large roots have previously been inferred to represent mafic underplates. Pressure-variability in the uppermost lithospheric mantle reduces to a minimum at ~125 km depth, suggesting that these loads are compensated by dense mantle at ~100 km depth, rather than by crustal loads or topography. This raises the notion that Australia's lithosphere is isostatically compensated at two levels: Crustal compensation involving topography and the felsic to intermediate crust; and deep-lithosphere compensation involving the mafic lower crust and lithospheric mantle. Rather than its traditional role of compensating for crustal masses, the Moho in this case appears to be a source of isostatic disequilibrium, acting in a separate cell with lithospheric mantle density sources. These results imply that, for cratonised continents like Australia, the notion of crustal isostasy is a poor descriptor of the system.

  10. Glacial Isostatic Adjustment Observed with VLBI and SLR

    NASA Technical Reports Server (NTRS)

    Argus, D.; Peltier, W.; Watkins, M.

    1999-01-01

    In global geodetic solutions vertical rates of site motion are usually estimated relative to the geocenter (center of figure) of the solid earth. The velocity of the geocenter is estimated assuming that the plates are rigid, that the velocities of the plates equal those in NUVEL-1A (DeMets et al. 1990, 1994) and that the uplift, subsidence, and intraplate deformation due to glacial isostatic adjustment is negligible.

  11. Reciprocating pellet press

    DOEpatents

    Jones, Charles W.

    1981-04-07

    A machine for pressing loose powder into pellets using a series of reciprocating motions has an interchangeable punch and die as its only accurately machines parts. The machine reciprocates horizontally between powder receiving and pressing positions. It reciprocates vertically to press, strip and release a pellet.

  12. The Global University Press

    ERIC Educational Resources Information Center

    Dougherty, Peter J.

    2012-01-01

    The modern world's understanding of American university press has long been shaped by university-press books. American university-press books are good international advertisements for the universities whose logos grace their spines. The growth of transnational scholarship and the expansion of digital communications networks are converging in ways…

  13. Comparison of different pressing techniques for the preparation of n-type silicon-germanium thermoelectric alloys

    SciTech Connect

    Harringa, J.L.; Cook, B.A.

    1996-06-01

    Improvements to state-of-the-art Si{sub 80}Ge{sub 20} thermoelectric alloys have been observed in laboratory-scale samples by the powder metallurgy techniques of mechanical alloying and hot pressing. Incorporating these improvements in large scale compacts for the production of thermoelectric generator elements is the next step in achieving higher efficiency RTGs. This paper discusses consolidation of large quantities of mechanically alloyed powders into production size compacts. Differences in thermoelectric properties are noted between the compacts prepared by the standard technique of hot uniaxial pressing and hot isostatic pressing. Most significant is the difference in carrier concentration between the alloys prepared by the two consolidation techniques.

  14. Dry pressing technical ceramics

    SciTech Connect

    Lewis, W.A. Jr.

    1996-04-01

    Dry pressing of technical ceramics is a fundamental method of producing high-quality ceramic components. The goals of dry pressing technical ceramics are uniform compact size and green density, consistent part-to-part green density and defect-free compact. Dry pressing is the axial compaction of loosely granulated dry ceramic powders (< 3% free moisture) within a die/punch arrangement. The powder, under pressure, conforms to the specific shape of the punch faces and die. Powder compaction occurs within a rigid-walled die and usually between a top and bottom punch. Press configurations include anvil, rotary, multiple-punch and multiple-action.

  15. Growth of yttrium orthovanadate by LHPG in isostatic oxygen atmosphere

    NASA Astrophysics Data System (ADS)

    Reyes Ardila, D.; de Camargo, A. S. S.; Andreeta, J. P.; Nunes, L. A. O.

    2001-11-01

    The growth of undoped and Nd 3+-doped YVO 4 crystals in isostatic oxygen atmosphere by the laser-heated pedestal growth technique was investigated. Absorption, photoluminescence, X-ray powder diffraction and Raman shift spectra were used to characterize the grown crystals. Differences in Y-V and oxygen stoichiometries were identified and discussed in terms of the starting materials processing, crystal growth dynamics and post-growth thermal treatment. The experimental results indicate that single crystal fibers with general optical and spectroscopic properties close to those of the best respective available bulk single crystals were grown.

  16. Origins of topological bulk modes in isostatic lattices

    NASA Astrophysics Data System (ADS)

    Rocklin, D. Zeb; Chen, Bryan; Falk, Martin; Lubensky, Tom; Vitelli, Vincenzo

    2015-03-01

    Mechanical lattices under periodic boundary conditions with coordination z = 2 d , where d is the spatial dimensionality, and with a gapped phonon spectrum at all wavenumbers not equal to zero are isostatic. When cut, these lattices with N sites in two dimensions necessarily have of order N 1 / 2 zero modes on their boundaries. Recently, Kane and Lubensky showed that these systems can be described by a super-symmetric Hamiltonian analogous to that of the Su-Schrieffer model for polyacetylene and they identified a topological invariant, the topological polarization, that determines on which edges zero modes lie in finite systems. We show that a family of two-dimensional four-site-per-unit-cell isostatic lattices possess topologically protected bulk zero modes. These ``Weyl modes'' are novel, tunable low-energy mechanisms of the mechanical lattice. They are the analogs of the zero-energy electronic modes of topological semimetals. We discuss how adjusting the lattice parameters induces Weyl modes and alters their wavevectors (generally incommensurate with the lattice) and how they can transport zero modes from one edge to an opposite one as surface wavenumber varies. An accompanying talk discusses the novel dynamical properties of the system.

  17. ITRF2008 solution, geodetic parameters and Glacial Isostatic Adjustment

    NASA Astrophysics Data System (ADS)

    Metivier, L.; Collilieux, X.; Greff-Lefftz, M.; Altamimi, Z.

    2011-12-01

    Glacial Isostatic Adjustment (GIA) leads to long term crust motion, gravity variation, sea level rise and perturbation of Earth rotation. Recent studies have enlightened unexpected differences between a few recent GIA models mostly due to the way GIA induced rotational feedback is modeled. The validity and quality of these models have been essentially discussed with respect to space gravity observations. Here, we investigate what information the up-to-date International Terrestrial Reference Frame solution, ITRF2008, provides on large scale geodetic observables and by extension on Glacial Isostatic Adjustment (GIA) and recent ice melting processes. We particularly focus on the GNSS network of ITRF2008 solution because of the present day high precision of GNSS technique and because of the good density of the GNSS network. From these data, we infer and study large scale geodetic parameters and their time evolutions, such as Earth oblateness and J2 rate, or secular rotational feedback. We also investigate different GIA and recent ice melting models.

  18. High School Press Pressures.

    ERIC Educational Resources Information Center

    Rogers, Luella P.

    History shows that the high school press suffers through cycles that reflect economic factors and cultural climates within communities, states, and the nation. The direction of that cycle in the 1960s and early 1970s was toward more open, free-flowing information by a vigorous student press, but those economic and cultural signs now are pointing…

  19. Lyndon Johnson's Press Conferences.

    ERIC Educational Resources Information Center

    Cooper, Stephen

    Because President Lyndon Johnson understood well the publicity value of the American news media, he sought to exploit them. He saw reporters as "torch bearers" for his programs and policies and used the presidential press conference chiefly for promotional purposes. Although he met with reporters often, his press conferences were usually…

  20. A deterministic approach toward isostatic gravity residuals: A case study from South America

    SciTech Connect

    Chapin, D.A.

    1994-12-31

    Isostatic gravity residuals are based upon geologic models, therefore they provide a reasonable basis of comparison over large areas for reconnaissance studies. To help define the best isostatic model for South America, a new deterministic methodology overcomes the deficiencies of other empirically-based methods. The basis for the model was the Airy-Heiskanen (1958) isostatic model, which assumes that surface topography is supported by crustal thickening. The three key parameters -- (a) the crustal thickness at sea-level, (b) the surface reduction density, and (c) the density contrast between the crust and the mantle -- were determined directly from the elevation, free-air gravity, and Bouguer gravity datasets. The results of this work were not only an isostatic residual map, but methodology which cross-checks the data for quality control purposes. The final isostatic residual map can be used in confidence for basin evaluation throughout the continent of South America.

  1. The isostatic state of the lunar Apennines and regional surroundings

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.; Sjogren, W. L.; Phillips, R. J.; Nelson, D. L.

    1978-01-01

    High-resolution gravity and topography data taken over the Apennine Mountains have been used to compute their isostatic state. Results show that the Apennines are uncompensated; thus this state implies that the lunar crust and upper mantle have been strong enough over 3.9 b.y. to support the load exerted by this topographic excess. The Apennines produce a maximum shear stress of 60 bars at a depth of 60 km. A lower bound on the lunar crustal viscosity of 10 to the 27th power P is calculated on the basis of the assumption of a 10% relaxation over 3.9 b.y. Studies of a broad negative regional anomaly located between Maria Serenitatis and Imbrium necessitate a locally thicker crust to satisfy the observed data. This anomaly may have been produced by a lateral transport of crustal material from beneath the giant impact basins as a result of rebound at the crust-mantle interface.

  2. Trashing the Press.

    ERIC Educational Resources Information Center

    McMasters, Paul

    1994-01-01

    Discusses ominous assaults on press freedom on college campuses across the United States. Laments the lack of concern about First Amendment issues involved in these incidents, in which student newspapers have been stolen, trashed, and burned. (SR)

  3. Design and analysis of isostatic mounts on a spaceborne lightweight primary mirror

    NASA Astrophysics Data System (ADS)

    Chan, C. Y.; Chen, Y. C.; Chang, S. T.; Huang, T. M.; Hsu, M. Y.

    2013-09-01

    The paper is aimed at obtaining the optimum isostatic mount configuration for a ZERODUR® primary mirror with a predesigned lightweight configuration on the back for a space Cassegrain telescope. The finite element analysis and Zernike polynomial fitting based on the Taguchi method are applied to the whole optimization process. Under the integrated optomechanical analysis, three isostatic mounts are bonded to the center of gravity of the mirror. Geometrical control factors and levels have been selected to minimize the optical aberrations under self-weight loading. The optimum isostatic mount with the least induced astigmatism value is finally attained under the Taguchi method.

  4. Glacial Isostatic Adjustment - a hot topic in cold regions

    NASA Astrophysics Data System (ADS)

    Whitehouse, Pippa

    2016-04-01

    Glacial Isostatic Adjustment (GIA) modelling tackles the classic geodynamical problem of determining the solid Earth response to surface load changes by ice and ocean water whilst at the same time solving for the gravitationally-consistent redistribution of ice sheet meltwater across the global ocean. Understanding this process is important for quantifying both present-day ice mass balance and the response of ice sheets to past and future climatic change. The two fundamental unknowns in this problem are (i) the rheology of the solid Earth, and (ii) the history of global ice sheet change. In this talk I will discuss the myriad of approaches that are used to constrain these two components. In particular, I will focus on Antarctica, where the presence of a continuously-evolving ice sheet, situated on top of one of the most rheologically-diverse regions of the planet, provides us with a challenge that can only be resolved by drawing on knowledge from across the fields of geodynamics, glaciology, geology, geodesy and seismology.

  5. The static contribution of Glacial Isostatic Adjustment on the Geoid

    NASA Astrophysics Data System (ADS)

    Metivier, L.; Greff-Lefftz, M.

    2012-04-01

    The Glacial Isostatic Adjustment (GIA) is due to the unloading of ice on the Earth surface following the last deglaciation period a few thousand years ago. The ice mass redistributions induce an adjustment of the planet. Following this adjustment, there are viscoelastic deformations of the solid Earth, sea level rise, gravity variations, geocenter motions, and also disruption of the Earth's rotation. We investigate here the present-day impact of GIA on the "static" component of the geoid. It is well known that GIA processes induce slow time variations of the gravity and the geoid shape. The total accumulation of the geoid changes since the beginning of the last deglaciation induces a total geoid perturbation that seems today constant in time at the human time scale. We want here to infer precisely the magnitude of this constant component in order to construct a GIA free-geoid. We tested different GIA models and tested different Earth viscosity profiles. We show that the GIA induces a constant perturbation of the geoid that can be quite important over North America and Scandinavia regions, depending on Earth models.

  6. Standard specification for hot isostatically-pressed alloy steel flanges, fittings, valves, and parts for high temperature service. ASTM standard

    SciTech Connect

    1998-09-01

    This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee A01.22 on Steel Forgings and Wrought Fittings for Piping Applications and Bolting Materials for Piping and Special Purpose Applications. Current edition approved Mar. 10, 1998 and published September 1998.

  7. Ag-doped FeSe0.94 polycrystalline samples obtained through hot isostatic pressing with improved grain connectivity

    NASA Astrophysics Data System (ADS)

    Gajda, G.; Morawski, A.; Rogacki, K.; Cetner, T.; Zaleski, A. J.; Buchkov, K.; Nazarova, E.; Balchev, N.; Hossain, M. S. A.; Diduszko, R.; Gruszka, K.; Przysłupski, P.; Fajfrowski, Ł.; Gajda, D.

    2016-09-01

    We evaluate the effects of high pressure during annealing on the structural and superconducting properties of Ag-doped FeSe bulks. The results obtained in this work indicate that the annealing at high pressure increases the critical temperature, upper critical field and irreversibility field due to the improved uniformity and grain connectivity.

  8. Physical properties of a nickel-base alloy prepared by isostatic pressing and sintering of the powdered metal.

    PubMed

    Fuys, R A; Craig, R G; Asger, K

    1976-04-01

    The physical and mechanical properties of samples of a nickel-base alloy fabricated by powder metallurgy were determined. The particle sizes of the powders used to make the samples varied from -80/ +200 mesh to -325 mesh. The compaction pressure varied from 138 to 414 MN/m2 and the sintering temperature varied from 1150 to 1250 degrees C. The shrinkage during processing, the porosity, tensile strength, yield strength, elongation, and elastic modulus were used to characterize the samples. The strength of the samples generally increased with decreasing particle size of the powder and increasing compaction pressure and sintering temperatures. The porosity and strength, therefore, could be varied over a wide range by controlling the various parameters. The properties of the samples prepared by powder metallurgy were compared with those of the cast alloy and compact bone. Conditions can be selected that will yield equivalent or better properties by powder metallurgy than by casting. PMID:1066448

  9. Microstructural anomalies in hot-isostatic pressed U–10wt.% Mo fuel plates with Zr diffusion barrier

    SciTech Connect

    Park, Y.; Eriksson, N.; Keiser, D. D.; Jue, J.; Rabin, B.; Moore, G.; Sohn, Y. H.

    2015-05-01

    Microstructural anomalies in the co-rolled-and-HIP'ed U–10 wt.% Mo (U10Mo) metallic fuel plate with Zr diffusion barrier assembly were examined as a function of HIP temperature (from 520 to 580 °C) and duration (45, 60, 90, 180 and 345 min) by scanning and transmission electron microscopy. The anomalies observed in this study are carbide/oxide inclusions within the U10Mo fuel alloy, and regions of limited interaction between the U10Mo alloy and Zr barrier, frequently associated with carbide/oxide inclusions. In the U10Mo alloy, the cF8, Fm3m (225) UC phase (a=4.955 Å) and cF12, Fm3m (225) UO2 phase (a=5.467 Å) were observed throughout the U10Mo alloy with an approximate volume percent of 0.5 to 1.8. The volume percent of the UC–UO2 inclusions within the U10Mo alloy did not change as functions of HIP temperature and time. These inclusion phases, located near the surface of the U10Mo alloy, were frequently observed to impede the development of interdiffusion and reaction between the U10Mo alloy and Zr diffusion barrier. The regions of limited interaction between the U10Mo and Zr barrier decreased with an increase in HIP temperature, however no noticeable trend was observed with an increase in HIP duration at constant temperature of 560 °C.

  10. The Manufacture of W-UO2 Fuel Elements for NTP Using the Hot Isostatic Pressing Consolidation Process

    NASA Technical Reports Server (NTRS)

    Broadway, Jeramie; Hickman, Robert; Mireles, Omar

    2012-01-01

    NTP is attractive for space exploration because: (1) Higher Isp than traditional chemical rockets (2)Shorter trip times (3) Reduced propellant mass (4) Increased payload. Lack of qualified fuel material is a key risk (cost, schedule, and performance). Development of stable fuel form is a critical path, long lead activity. Goals of this project are: Mature CERMET and Graphite based fuel materials and Develop and demonstrate critical technologies and capabilities.

  11. Press-On Optics

    ERIC Educational Resources Information Center

    Thorson, Jon C.

    1972-01-01

    The article discusses the design, application, and clinical uses of press-on optics which are descirbed as 1 millimeter thick, flexible lenses or prisms that may be produced in virtually any desired plus or minus dioptric power as ophthalmic lenses, or in any range of usable prism diopter power. (GW)

  12. Meet the Press

    ERIC Educational Resources Information Center

    Quick, Brian L.

    2004-01-01

    Objective: To field questions from a room of students simulating a press conference. Type of speech: Impromptu. Point value: 10 participation points. To receive all 10 points, students must (1) address three questions from the lectern and ask three questions from their seat (3 points), (2) respond thoroughly to each question by providing a…

  13. Optically Aligned Drill Press

    NASA Technical Reports Server (NTRS)

    Adderholdt, Bruce M.

    1994-01-01

    Precise drill press equipped with rotary-indexing microscope. Microscope and drill exchange places when turret rotated. Microscope axis first aligned over future hole, then rotated out of way so drill axis assumes its precise position. New procedure takes less time to locate drilling positions and produces more accurate results. Apparatus adapted to such other machine tools as milling and measuring machines.

  14. Drill Press Work Sample.

    ERIC Educational Resources Information Center

    Shawsheen Valley Regional Vocational-Technical High School, Billerica, MA.

    This manual contains a work sample intended to assess a handicapped student's interest in and to screen interested students into a training program in basic machine shop I. (The course is based on the entry level of the drill press operator.) Section 1 describes the assessment, correlates the work performed and worker traits required for…

  15. Importance of far-field Topographic and Isostatic corrections for regional density modeling

    NASA Astrophysics Data System (ADS)

    Szwillus, Ebbing, Holzrichter

    2016-07-01

    The long-wavelength gravity field contains information about processes in the sub-lithospheric mantle. As satellite-derived gravity models now provide the long to medium-wavelength gravity field at unprecedented accuracy, techniques used to process gravity data need to be updated. We show that when determining these long-wavelengths, the treatment of topographic and isostatic effects is a likely source of error. We constructed a global isostatic model and calculated global topographic and isostatic effect. These calculations were done for ground stations as well as stations at satellite height. We considered both gravity and gravity gradients. Using these results, we determined how much of the gravity signal comes from distant sources. We find that a significant long-wavelength bias is introduced if far-field effects on the topographic effect are neglected. However, due to isostatic compensation far-field effects of the topographic effect are to a large degree compensated by the far-field isostatic effect. This means that far-field effects can be reduced effectively by always considering topographic masses together with their compensating isostatic masses. We show that to correctly represent the ultra-long wavelengths, a global background model should be used. This is demonstrated both globally and for a continental-scale case area in North America. In the case of regional modeling, where the ultra-long wavelengths are not of prime importance, gravity gradients can be used to help minimize correction errors caused by far-field effects.

  16. Worldwide complete spherical Bouguer and isostatic anomaly maps

    NASA Astrophysics Data System (ADS)

    Bonvalot, S.; Balmino, G.; Briais, A.; Peyrefitte, A.; Vales, N.; Biancale, R.; Gabalda, G.; Reinquin, F.

    2011-12-01

    We present here a set of digital maps of the Earth's gravity anomalies (surface "free air", Bouguer and isostatic), computed at Bureau Gravimetric International (BGI) as a contribution to the Global Geodetic Observing Systems (GGOS) and to the global geophysical maps published by the Commission for the Geological Map of the World (CGMW). The free air and Bouguer anomaly concept is extensively used in geophysical interpretation to investigate the density distributions in the Earth's interior. Complete Bouguer anomalies (including terrain effects) are usually computed at regional scales by integrating the gravity attraction of topography elements over and beyond a given area (under planar or spherical approximations). Here, we developed and applied a worldwide spherical approach aimed to provide a set of homogeneous and high resolution gravity anomaly maps and grids computed at the Earth's surface, taking into account a realistic Earth model and reconciling geophysical and geodetic definitions of gravity anomalies. This first version (1.0) has been computed by spherical harmonics analysis / synthesis of the Earth's topography-bathymetry up to degree 10800. The detailed theory of the spherical harmonics approach is given in Balmino et al., (Journal of Geodesy, submitted). The Bouguer and terrain corrections have thus been computed in spherical geometry at 1'x1' resolution using the ETOPO1 topography/bathymetry, ice surface and bedrock models from the NOAA (National Oceanic and Atmospheric Administration) and taking into account precise characteristics (boundaries and densities) of major lakes, inner seas, polar caps and of land areas below sea level. Isostatic corrections have been computed according to the Airy Heiskanen model in spherical geometry for a constant depth of compensation of 30km. The gravity information given here is provided by the Earth Geopotential Model (EGM2008), developed at degree 2160 by the National Geospatial Intelligence Agency (NGA) (Pavlis

  17. A benchmark study for glacial isostatic adjustment codes

    NASA Astrophysics Data System (ADS)

    Spada, G.; Barletta, V. R.; Klemann, V.; Riva, R. E. M.; Martinec, Z.; Gasperini, P.; Lund, B.; Wolf, D.; Vermeersen, L. L. A.; King, M. A.

    2011-04-01

    The study of glacial isostatic adjustment (GIA) is gaining an increasingly important role within the geophysical community. Understanding the response of the Earth to loading is crucial in various contexts, ranging from the interpretation of modern satellite geodetic measurements (e.g. GRACE and GOCE) to the projections of future sea level trends in response to climate change. Modern modelling approaches to GIA are based on various techniques that range from purely analytical formulations to fully numerical methods. Despite various teams independently investigating GIA, we do not have a suitably large set of agreed numerical results through which the methods may be validated; a community benchmark data set would clearly be valuable. Following the example of the mantle convection community, here we present, for the first time, the results of a benchmark study of codes designed to model GIA. This has taken place within a collaboration facilitated through European Cooperation in Science and Technology (COST) Action ES0701. The approaches benchmarked are based on significantly different codes and different techniques. The test computations are based on models with spherical symmetry and Maxwell rheology and include inputs from different methods and solution techniques: viscoelastic normal modes, spectral-finite elements and finite elements. The tests involve the loading and tidal Love numbers and their relaxation spectra, the deformation and gravity variations driven by surface loads characterized by simple geometry and time history and the rotational fluctuations in response to glacial unloading. In spite of the significant differences in the numerical methods employed, the test computations show a satisfactory agreement between the results provided by the participants.

  18. Four Theories of the Press.

    ERIC Educational Resources Information Center

    Siebert, Fred S.; And Others

    A systematic understanding of the press requires an understanding of the social and political structures within which the press operates. This book discusses four theories that have determined the kind of press the Western world has had: authoritarian, libertarian, socially responsible, and Soviet communist. Each chapter discusses press…

  19. Bouguer gravity anomaly and isostatic residual gravity maps of the Tonopah 1 degree by 2 degrees Quadrangle, central Nevada

    USGS Publications Warehouse

    Plouff, Donald

    1992-01-01

    A residual isostatic gravity map (sheet 2) was prepared so that the regional effect of isostatic compensation present on the Bouguer gravity anomaly map (sheet 1) would be minimized. Isostatic corrections based on the Airy-Heiskanen system (Heiskanen and Vening Meinesz, 1958, p. 135-137) were estimated by using 3-minute topographic digitization and applying the method of Jachens and Roberts (1981). Parameters selected for the isostatic model were 25 km for the normal crustal thickness at sea level, 2.67 g/cm3 for the density of the crust, and 0.4 g/cm3 for the contrast in density between the crust and the upper mantle. These parameters were selected so that the isostatic residual gravity map would be consistent with isostatic residual gravity maps of the adjacent Walker Lake quadrangle (Plouff, 1987) and the state of Nevada (Saltus, 1988c).

  20. Variations in Crustal Structure, Lithospheric Flexural Strength, and Isostatic Compensation Mechanisms of Mars

    NASA Astrophysics Data System (ADS)

    Ding, M.; Lin, J.; Zuber, M. T.

    2014-12-01

    We analyze gravity and topography of Mars to investigate the spatial variations in crustal thickness, lithospheric strength, and mechanisms of support of prominent topographic features on Mars. The latest gravity model JGMRO110c (released in 2012) from the Mars Reconnaissance Orbiter mission has a spatial block size resolution of ~97 km (corresponding to degree-110), enabling us to resolve crustal structures at higher spatial resolution than those determined from previous degree-80 and 85 gravity models [Zuber et al., 2000; McGovern et al., 2002, 2004; Neumann et al., 2004; Belleguic et al., 2005]. Using the latest gravity data, we first inverted for a new version of crustal thickness model of Mars assuming homogeneous crust and mantle densities of 2.9 and 3.5 g/cm3. We calculated "isostatic" topography for the Airy local isostatic compensation mechanism, and "non-isostatic" topography after removing the isostatic part. We find that about 92% of the Martian surface is in relatively isostatic state, indicating either relatively small lithospheric strength and/or small vertical loading. Relatively isostatic regions include the hemispheric dichotomy, Hellas and Argyre Planitia, Noachis and Arabia Terra, and Terra Cimmeria. In contrast, regions with significant amount of non-isostatic topography include the Olympus, Ascraeus, Arsia, Pavonis, Alba, and Elysium Mons, Isidis Planitia and Valles Marineris. Their relatively large "non-isostatc topography" implies relatively strong lithospheric strength and large vertical loading. Spectral analysis of the admittance and correlation relationship between gravity and topography were conducted for the non-isostatic regions using the localized spectra method [Wieczorek and Simons, 2005, 2007] and thin-shell lithospheric flexural approximation [Forsyth, 1985; McGovern et al., 2002, 2004]. The best-fitting models reveal significant variations in the effective lithospheric thickness with the greatest values for the Olympus Mon

  1. Do crustal deformations observed by GPS in Tierra del Fuego (Argentina) reflect glacial-isostatic adjustment?

    NASA Astrophysics Data System (ADS)

    Mendoza, L.; Richter, A.; Hormaechea, J. L.; Perdomo, R.; Del Cogliano, D.; Dietrich, R.; Fritsche, M.

    2010-09-01

    Vertical site velocities determined by geodetic GPS observations in the Lago Fagnano area, Tierra del Fuego main island, are interpreted with respect to their potential relation with the glacial-isostatic crustal response to ice mass changes. The spatial pattern of the uplift rates, in combination with the horizontal crustal deformation pattern, point towards a fault-tectonic rather than glacial-isostatic origin of the determined vertical crustal deformations. This implies rather small GIA effects pointing towards relatively small Holocene ice-mass changes in Tierra del Fuego. However, these findings are considered to be preliminary. They should be confirmed by additional observations covering an extended area with GPS sites.

  2. Australia's lithospheric density field, and its isostatic equilibration

    NASA Astrophysics Data System (ADS)

    Aitken, A. R. A.; Altinay, C.; Gross, L.

    2015-12-01

    subdivisions within each. The lithospheric static pressure field was resolved in 3D from the gravity and density fields. The pressure field model also highlights the fundamental difference between the oceanic and continental domains, with the former possessing lower pressure through most of the model. Overall pressure variability is large in the upper crust (60 MPa) but reduces significantly by -30 km elevation (20-30 MPa). By -50 km elevation, thick lower-crust generates further disequilibria (25-35 MPa) that are not compensated until -125 km elevation (10-20 MPa). Beneath -125 km elevation higher pressure is observed in the continental domain, extending to the base of the model. This indicates a lithosphere that is to a large degree isostatically compensated near the base of the felsic-intermediate continental crust, and again near the theoretical base of mature oceanic lithosphere.

  3. CIDER PRESS, LOOKING SOUTHEAST ACROSS THE SCHUYLKILL RIVER. THIS PRESS, ...

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

    CIDER PRESS, LOOKING SOUTHEAST ACROSS THE SCHUYLKILL RIVER. THIS PRESS, CARVED OUT OF A LARGE BOULDER AT THE RIVERS EDGE, PROBABLY DATES FROM THE LIFETIME OF JOHN BARTRAM, IF NOT TO THE SWEDISH SETTLERS BEFORE HIM. THE IRON FENCE IS A NINETEENTH-CENTURY ADDITION - John Bartram House & Garden, 54th Street & Lindbergh Boulevard, Philadelphia, Philadelphia County, PA

  4. PRESS SHOP. SEVEN BLISS PRESSES STAMP OUT A VARIETY OF ...

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

    PRESS SHOP. SEVEN BLISS PRESSES STAMP OUT A VARIETY OF CARTRIDGE AND SHELL CASINGS. THIS DEPARTMENT WAS TRANSFORMED FROM A MONEY-LOSING OPERATION TO A PROFIT CENTER UNDER THE FIRST WORKER-MANAGED QUALITY CIRCLE IN THE PLANT. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  5. Separation of dynamic and isostatic components of the Venusian gravity and topography and determination of the crustal thickness of Venus

    NASA Astrophysics Data System (ADS)

    Yang, An; Huang, Jinshui; Wei, Daiyun

    2016-09-01

    Assuming that the long-wavelength geoid and topography of Venus are supported by both mantle convection and Airy isostasy, we propose a method to separate the dynamic and isostatic components of the Venusian gravity and topography with the aid of the dynamic admittance from numerical models of mantle convection and the isostatic admittance from an Airy isostatic model. The global crustal thickness is then calculated based on the isostatic component of the gravity and topography. The results show that some highland plateaus such as Ishtar Terra and Ovda Regio have thick crust, which are largely supported by isostatic compensation. Other highland plateaus such as Thetis and Phoebe Regiones appear to have superimposed contributions from crustal thickening and dynamic support. Volcanic rises such as Atla and Beta Regiones have thin crust, which is consistent with the postulation that these volcanic rises are mainly the products of dynamic uplift caused by mantle plumes.

  6. Isostatic gravity disturbances in the definition of the Vening-Meinesz Moritz inverse problem of isostasy

    NASA Astrophysics Data System (ADS)

    Tenzer, Robert; Bargherbandi, Mohammad; Sjoeberg, Lars E.; Novák, Pavel

    2013-04-01

    The isostatic gravity anomalies have been traditionally used to solve the inverse problems of isostasy. Since gravity measurements are nowadays carried out together with GPS positioning, the utilization of gravity disturbances in various regional gravimetric applications becomes possible. In global studies, the gravity disturbances can be computed using global geopotential models which are currently available to a very high accuracy and resolution. In this study we facilitate the definition of the isostatic gravity disturbances in the Vening-Meinesz Moritz inverse problem of isostasy for finding the Moho depths. We further utilize uniform mathematical formalism in the gravimetric forward modelling based on methods for a spherical harmonic analysis and synthesis of gravity field. We then apply both mathematical procedures to determine globally the Moho depths using the isostatic gravity disturbances. The results of gravimetric inversion are finally compared with the global crustal seismic model CRUST2.0; the RMS fit of the gravimetric Moho model with CRUST2.0 is 5.3 km. This is considerably better than the RMS fit of 7.0 km obtained after using the isostatic gravity anomalies.

  7. The CIA and the Press.

    ERIC Educational Resources Information Center

    Carvalho, Bernardo A.

    The involvement of the Central Intelligence Agency (CIA) with both United States and foreign news media has been recorded in numerous publications. This report reviews the important aspects of the CIA-press relationships as they have appeared in print and discusses the implications of these relationsihps for the credibility of the press. Media…

  8. Press, Politics and Popular Government.

    ERIC Educational Resources Information Center

    Will, George F., Ed.

    A panel discussion on politics and the press was held at the convention of the American Political Science Association in September 1971. This volume contains an essay delivered at that panel on the various functions or activities of the press--adversary, surrogate, sovereign--and remarks of the three discussants. In addition, an essay especially…

  9. On Gravity Inversion by No-Topography and Rigorous Isostatic Gravity Anomalies

    NASA Astrophysics Data System (ADS)

    Sjöberg, Lars E.; Bagherbandi, Mohammad; Tenzer, Robert

    2015-10-01

    We discuss some theoretical aspects and practical consequences of using traditional versus "new"/rigorous formulations of the Bouguer and isostatic gravity anomalies/disturbances. In principle, the differences between these two concepts are in the definition of the so-called secondary indirect topographic effect (SITE) on the gravity data. Although we follow the tradition to call this effect SITE, we show that it is formally a direct topographic effect (DITE), needed to remove all topographic signal, but in practice not regarded as such. Consequently, there is a need for a no- topography gravity anomaly, which removes all topographic effects, leaving the below-crust Earth transparent for gravity inversion. Similarly, a rigorous isostatic gravity anomaly includes also a compensation effect for the SITE. By using a simple topographic model, we confirm a theoretically found ratio of 2/( n + 1) between the magnitudes of the SITE and DITE by wavelength (spherical harmonic degree n), both for the Bouguer and isostatic gravity anomalies. Finally, global gravity inversions are applied by utilizing the Vening Meinesz-Moritz isostatic model to determine the Moho geometry using the Bouguer gravity disturbances/anomalies and the no-topography gravity anomalies, and the results are compared. The numerical results confirm our theoretical findings that the Bouguer gravity disturbances and the no-topography gravity anomalies provide very similar results. A comparison of these gravimetrically computed Moho depths with the CRUST1.0 seismic model shows rms agreements of 4.3 and 4.5 km, respectively. This is a significant improvement when compared to the Moho result obtained by using the Bouguer gravity anomalies, yielding the rms difference of 7.3 km for the CRUST1.0 model. These results confirm a theoretical deficiency of the classical definition of the Bouguer and isostatic gravity anomalies, which do not take into consideration the SITE effects on the topography and its

  10. The Press Research Centre, 1956-1976.

    ERIC Educational Resources Information Center

    Press Research Centre, Krakow (Poland).

    In 1956, the Press Research Centre was established in Cracow, Poland by a group of journalists and publishers, for the purpose of instituting press research that would have practical applications. The aims of the Centre were to conduct studies on the history of the Polish press, the contemporary press, press readership, and editorial techniques.…

  11. Investing in a Large Stretch Press

    NASA Technical Reports Server (NTRS)

    Choate, M.; Nealson, W.; Jay, G.; Buss, W.

    1986-01-01

    Press for forming large aluminum parts from plates provides substantial economies. Study assessed advantages and disadvantages of investing in large stretch-forming press, and also developed procurement specification for press.

  12. Global isostatic geoid anomalies for plate and boundary layer models of the lithosphere

    NASA Technical Reports Server (NTRS)

    Hager, B. H.

    1981-01-01

    Commonly used one dimensional geoid models predict that the isostatic geoid anomaly over old ocean basins for the boundary layer thermal model of the lithosphere is a factor of two greater than that for the plate model. Calculations presented, using the spherical analogues of the plate and boundary layer thermal models, show that for the actual global distribution of plate ages, one dimensional models are not accurate and a spherical, fully three dimensional treatment is necessary. The maximum difference in geoid heights predicted for the two models is only about two meters. The thermal structure of old lithosphere is unlikely to be resolvable using global geoid anomalies. Stripping the effects of plate aging and a hypothetical uniform, 35 km, isostatically-compensated continental crust from the observed geoid emphasizes that the largest-amplitude geoid anomaly is the geoid low of almost 120 m over West Antarctica, a factor of two greater than the low of 60 m over Ceylon.

  13. Study of bonding positions of isostatic mounts on a lightweight primary mirror

    NASA Astrophysics Data System (ADS)

    Chan, C. Y.; Chen, Y. C.; Chang, S. T.; Huang, T. M.; Hsu, M. Y.

    2012-10-01

    The bonding positions of three isostatic mounts on the primary mirror of a Cassegrain telescope under self-weight loading have both been studied in the paper. Finite element method and Zernike polynomial fitting are complementarily applied to the ZERODUR® primary mirror with a pre-designed lightweight configuration on the back. Eight bonding positions of isostatic mounts with respect to the center of gravity of the mirror have been chosen to investigate the mirror surface deforms as well as the induced optical aberrations. It is found that astigmatism becomes remarkably higher than other optical aberrations under self-weight loading. The optimum bonding position with the least astigmatism value has also been obtained.

  14. Isostatic gravity map with simplified geology of the Los Angeles 30 x 60 minute quadrangle

    USGS Publications Warehouse

    Wooley, R.J.; Yerkes, R.F.; Langenheim, V.E.; Chuang, F.C.

    2003-01-01

    This isostatic residual gravity map is part of the Southern California Areal Mapping Project (SCAMP) and is intended to promote further understanding of the geology in the Los Angeles 30 x 60 minute quadrangle, California, by serving as a basis for geophysical interpretations and by supporting both geological mapping and topical (especially earthquake) studies. Local spatial variations in the Earth's gravity field (after various corrections for elevation, terrain, and deep crustal structure explained below) reflect the lateral variation in density in the mid- to upper crust. Densities often can be related to rock type, and abrupt spatial changes in density commonly mark lithologic boundaries. The map shows contours of isostatic gravity overlain on a simplified geology including faults and rock types. The map is draped over shaded-relief topography to show landforms.

  15. Large floor-fractured craters and isostatic crater modification: Implications for lithospheric thickness on Venus

    NASA Astrophysics Data System (ADS)

    Wichman, R. W.; Schultz, P. H.

    1993-03-01

    Several of the largest craters on Venus, including Mead, Meitner and Isabella, exhibit well-developed floor fracture patterns combining a central set of radial features with a peripheral set of concentric fractures. This pattern strongly resembles the fracture patterns observed in the largest floor-fractured craters on the Moon (e.g. Humboldt, Gauss, Petavius). Although most lunar floor-fractured craters apparently reflect crater modification by igneous intrusions and volcanism, we propose that the fractures in these larger craters represent domical flexure events in response to post-impact isostatic uplift. Since the extent of uplift and surface failure in this model depends on both the size of the basin cavity and the local lithospheric thickness, this interpretation also provides a means for constraining lithospheric thicknesses on Venus. Based on the apparent onset diameter of isostatic crater modification, we derive lithospheric thickness estimates for the Moon of approximately 80 - 100 km, and for Venus of approximately 50 - 70 km.

  16. Degree variances of the earth's potential, topography and its isostatic compensation

    NASA Technical Reports Server (NTRS)

    Rapp, R. H.

    1982-01-01

    A spherical harmonic expansion of the earth's gravitational potential and equivalent rock topography to degree and order 180 is described. The potential implied by the topography considered as uncompensated and with isostatic compensation has been computed. Good agreement with the observed potential field is found when the depth of compensation in the Airy theory is assumed to be 50 km. At the higher degrees the correlation coefficient between the potential expansion and the equivalent rock topography is about 0.5. The Lachapelle equations for the topographic isostatic potential were tested using 1 x 1 deg equivalent rock topography. The degree variances agree at the lower degrees but at degree 36 the Lachapelle results using 5 deg data underestimate the potential degree variances by about one-third.

  17. Large floor-fractured craters and isostatic crater modification: Implications for lithospheric thickness on Venus

    NASA Technical Reports Server (NTRS)

    Wichman, R. W.; Schultz, P. H.

    1993-01-01

    Several of the largest craters on Venus, including Mead, Meitner and Isabella, exhibit well-developed floor fracture patterns combining a central set of radial features with a peripheral set of concentric fractures. This pattern strongly resembles the fracture patterns observed in the largest floor-fractured craters on the Moon (e.g. Humboldt, Gauss, Petavius). Although most lunar floor-fractured craters apparently reflect crater modification by igneous intrusions and volcanism, we propose that the fractures in these larger craters represent domical flexure events in response to post-impact isostatic uplift. Since the extent of uplift and surface failure in this model depends on both the size of the basin cavity and the local lithospheric thickness, this interpretation also provides a means for constraining lithospheric thicknesses on Venus. Based on the apparent onset diameter of isostatic crater modification, we derive lithospheric thickness estimates for the Moon of approximately 80 - 100 km, and for Venus of approximately 50 - 70 km.

  18. The development of an isostatic gravitational model to degree 360 and its use in global gravity modelling

    NASA Technical Reports Server (NTRS)

    Pavlis, N. K.; Rapp, R. H.

    1990-01-01

    Consideration is given to the possibility of combining low-degree satellite-derived geopotential models with the harmonic coefficients of the topographic-isostatic potential implied by the Airy/Heiskanen isostatic hypothesis. The compilation of a topographic database providing information pertaining to terrain type classification is discussed. The formulation for the determination of harmonic coefficients of the topographic-isostatic potential is extended beyond to cases discussed by Lachapelle (1976) to include various terrain types. This formulation and the series expansion approach of Rummel et al. (1988) are implemented for potential coefficient determinations complete to degree and order 360. The topographic-isostatic coefficients are used with satellite-derived geopotential models to estimate mean gravity anomalies. The results are compared with observations to evaluate the quality of different estimation procedures.

  19. The development of an isostatic gravitational model to degree 360 and its use in global gravity modelling

    NASA Astrophysics Data System (ADS)

    Pavlis, N. K.; Rapp, R. H.

    1990-03-01

    Consideration is given to the possibility of combining low-degree satellite-derived geopotential models with the harmonic coefficients of the topographic-isostatic potential implied by the Airy/Heiskanen isostatic hypothesis. The compilation of a topographic database providing information pertaining to terrain type classification is discussed. The formulation for the determination of harmonic coefficients of the topographic-isostatic potential is extended beyond to cases discussed by Lachapelle (1976) to include various terrain types. This formulation and the series expansion approach of Rummel et al. (1988) are implemented for potential coefficient determinations complete to degree and order 360. The topographic-isostatic coefficients are used with satellite-derived geopotential models to estimate mean gravity anomalies. The results are compared with observations to evaluate the quality of different estimation procedures.

  20. Isostaticity and Controlled Force Transmission in the Cytoskeleton: A Model Awaiting Experimental Evidence

    PubMed Central

    Blumenfeld, Raphael

    2006-01-01

    A new model is proposed for force transmission through the cytoskeleton (CSK). A general discussion is first presented on the physical principles that underlie the modeling of this phenomenon. Some fundamental problems of conventional models—continuous and discrete—are examined. It is argued that mediation of focused forces is essential for good control over intracellular mechanical signals. The difficulties of conventional continuous models in describing such mediation are traced to a fundamental assumption rather than to their being continuous. Relevant advantages and disadvantages of continuous and discrete modeling are discussed. It is concluded that favoring discrete models is based on two misconceptions, which are clarified. The model proposed here is based on the idea that focused propagation of mechanical stimuli in frameworks over large distances (compared to the mesh size) can only occur when considerable regions of the CSK are isostatic. The concept of isostaticity is explained and a recently developed continuous isostaticity theory is briefly reviewed. The model enjoys several advantages: it leads to good control over force mediation; it explains nonuniform stresses and action at a distance; it is continuous, making it possible to model force propagation over long distances; and it enables prediction of individual force paths. To be isostatic, or nearly so, CSK networks must possess specific structural characteristics, and these are quantified. Finally, several experimental observations are interpreted using the new model and implications are discussed. It is also suggested that this approach may give insight into the dynamics of reorganization of the CSK. Many of the results are amenable to experimental measurements, providing a testing ground for the proposed picture, and generic experiments are suggested. PMID:16912215

  1. A new method of computation of the isostatic anomaly and its application to the Rhine graben

    NASA Astrophysics Data System (ADS)

    Bernabe, Y.

    1981-11-01

    Using a preexisting mathematical model, a mathematical assumption of linearity is used to compute isostatic anomalies directly from geodetic and gravimetric data. When applied to the Rhine graben, the method yields satisfactory results which justify it a posteriori. The compensation depth is thought to be greater than 120 km. It is noted that the computation of a model of the distribution of compensation masses inside the earth necessitates further mathematical assumptions which make the results physically questionable.

  2. Existence of isostatic, maximally random jammed monodisperse hard-disk packings

    PubMed Central

    Atkinson, Steven; Stillinger, Frank H.; Torquato, Salvatore

    2014-01-01

    We generate jammed packings of monodisperse circular hard-disks in two dimensions using the Torquato–Jiao sequential linear programming algorithm. The packings display a wide diversity of packing fractions, average coordination numbers, and order as measured by standard scalar order metrics. This geometric-structure approach enables us to show the existence of relatively large maximally random jammed (MRJ) packings with exactly isostatic jammed backbones and a packing fraction (including rattlers) of ϕ=0.826. By contrast, the concept of random close packing (RCP) that identifies the most probable packings as the most disordered misleadingly identifies highly ordered disk packings as RCP in 2D. Fundamental structural descriptors such as the pair correlation function, structure factor, and Voronoi statistics show a strong contrast between the MRJ state and the typical hyperstatic, polycrystalline packings with ϕ≈0.88 that are more commonly obtained using standard packing protocols. Establishing that the MRJ state for monodisperse hard disks is isostatic and qualitatively distinct from commonly observed polycrystalline packings contradicts conventional wisdom that such a disordered, isostatic packing does not exist due to a lack of geometrical frustration and sheds light on the nature of disorder. This prompts the question of whether an algorithm may be designed that is strongly biased toward generating the monodisperse disk MRJ state. PMID:25512529

  3. Existence of isostatic, maximally random jammed monodisperse hard-disk packings.

    PubMed

    Atkinson, Steven; Stillinger, Frank H; Torquato, Salvatore

    2014-12-30

    We generate jammed packings of monodisperse circular hard-disks in two dimensions using the Torquato-Jiao sequential linear programming algorithm. The packings display a wide diversity of packing fractions, average coordination numbers, and order as measured by standard scalar order metrics. This geometric-structure approach enables us to show the existence of relatively large maximally random jammed (MRJ) packings with exactly isostatic jammed backbones and a packing fraction (including rattlers) of [Formula: see text]. By contrast, the concept of random close packing (RCP) that identifies the most probable packings as the most disordered misleadingly identifies highly ordered disk packings as RCP in 2D. Fundamental structural descriptors such as the pair correlation function, structure factor, and Voronoi statistics show a strong contrast between the MRJ state and the typical hyperstatic, polycrystalline packings with [Formula: see text] that are more commonly obtained using standard packing protocols. Establishing that the MRJ state for monodisperse hard disks is isostatic and qualitatively distinct from commonly observed polycrystalline packings contradicts conventional wisdom that such a disordered, isostatic packing does not exist due to a lack of geometrical frustration and sheds light on the nature of disorder. This prompts the question of whether an algorithm may be designed that is strongly biased toward generating the monodisperse disk MRJ state. PMID:25512529

  4. On the isostatic gravity anomaly and disturbance and their applications to Vening Meinesz-Moritz gravimetric inverse problem

    NASA Astrophysics Data System (ADS)

    Sjöberg, Lars E.

    2013-06-01

    In this study, we show that the traditionally defined Bouguer gravity anomaly needs a correction to become `the no-topography gravity anomaly' and that the isostatic gravity anomaly is better defined by the latter anomaly plus a gravity anomaly compensation effect than by the Bouguer gravity anomaly plus a gravitational compensation effect. This is because only the new isostatic gravity anomaly completely removes and compensates for the topographic effect. F. A. Vening Meinesz' inverse problem in isostasy deals with solving for the Moho depth from the known external gravity field and mean Moho depth (known, e.g. from seismic reflection data) by a regional isostatic compensation using a flat Earth approximation. H. Moritz generalized the problem to that of a global compensation with a spherical mean Earth approximation. The problem can be formulated mathematically as that of solving a non-linear Fredholm integral equation. The solutions to these problems are based on the condition of isostatic balance of the isostatic gravity anomaly, and, theoretically, this assumption cannot be met by the old definition of the isostatic gravity anomaly. We show how the Moho geometry can be solved for the gravity anomaly, gravity disturbance and disturbing potential, etc., and, from a theoretical point of view, all these solutions are the same.

  5. Apollo 13 Facts: Press Conference

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Flight Director Gene Krantz gives an overview of the Apollo 13 mission as corrections are made in the power down checklist, passive thermal control, and orbital burns after the spacecraft runs into problems. He then answers questions from the press with the help of Tony England, Bill Peters, and Dick Thorson. Footage then shows newspaper headlines 'We're Not Concerned' and 'Getting Ready to Land' as people watch televisions to see if the astronauts landed safely. The press conference section of this video has sound, the headlines section does not.

  6. Gifted Education Press Quarterly, 1995.

    ERIC Educational Resources Information Center

    Fisher, Maurice D., Ed.

    1995-01-01

    This document consists of the four issues of the newsletter "Gifted Education Press Quarterly" published during 1995. This newsletter addresses issues in the education of gifted children and youth. The major articles are: (1) "Using Today's Technology: Parents Can Help Challenge Gifted Children" (Adrienne O'Neill); (2) "Outcomes-Based Education…

  7. Law and the Student Press.

    ERIC Educational Resources Information Center

    Stevens, George E.; Webster, John B.

    Court cases and legal decisions involving the student press in the late 1960s and early 1970s are brought together in this book in order to show how the law has been applied to school officials and student journalists in high school, college, and the underground. The ten chapters cover the following topics: censorship, libel, obscenity, contempt,…

  8. NATIONAL ACADEMY PRESS WEB SITE

    EPA Science Inventory

    The National Academy Press is the publisher for the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council. Through this web site, you have access to a virtual treasure trove of books, reports and publicatio...

  9. 30th Arniversary Press Conference

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Marking the occasion of the Apollo 11 30th Anniversary, members of the Apollo and Saturn astronaut programs attended festivities at Marshall Space Flight Center in Huntsville, AL. A press conference was held at the U. S. Space and Rocket Center for the visiting astronauts. Pictured are (L/R): Edgar Mitchell, Walt Cunningham, Charlie Duke, Buzz Aldrin, Dick Gordon and Owen Garriott.

  10. Scheme of 3 interfaces with local isostatic compensation on the Argentine continental margin

    NASA Astrophysics Data System (ADS)

    Pedraza De Marchi, A. C.; Ghidella, M. E.; Tocho, C.

    2013-05-01

    The segment of Argentine continental margin located between 39°S and the Malvinas platform (~49°S) is of passive type and volcanic characteristics revealed by seaward-dipping seismic reflectors sequences (SDRs). The free air gravity edge-effect associated with passive continental margins is one of the most distinctive characteristics of gravity in marine regions. This effect is in large part due to the transition between continental and oceanic crusts, because of their different thicknesses. In this presentation we investigate the Airy type isostatic compensation scheme by using three interfaces in a forward calculation with different approximations of Parker's expression to obtain the isostatic anomaly. After that we perform the inversion of the anomaly thus obtained in order to find the Moho's deflection necessary to compensate it (or minimize it) by using the same scheme of interfaces and the iterative Parker-Oldenburg method (Oldenburg, D., 1974) with more terms in the inversion. The crust-mantle interface (Moho) thus calculated represents a more realistic surface than the one calculated using one term in the inversion and the surface estimated with topographic data and sediment thickness. Even considering that the experiment constitutes a schematic assumption just to test the numerical methods involved, we find that in the comparison with the only available digitized refraction profile, the inverted Moho interface reproduces fairly well the Moho that the seismic profile yields, for the case of the iterative method. This suggests that the inverse calculation with the iterative method is sensible to the presence of the SDRS, at least for this sole profile. Keywords: isostatic anomaly, Moho, passive continental margins Oldenburg, D., 1974. The inversion and interpretation of gravity anomalíes, Geophysics, vol. 39, no. 4, p. 526-536.

  11. The spherical terrain correction and its effect on the gravimetric-isostatic Moho determination

    NASA Astrophysics Data System (ADS)

    Abrehdary, M.; Sjöberg, L. E.; Bagherbandi, M.

    2016-01-01

    In this study, the Moho depth is estimated based on the refined spherical Bouguer gravity disturbance and DTM2006 topographic data using the Vening Meinesz-Moritz gravimetric-isostatic hypothesis. In this context, we compute the refined spherical Bouguer gravity disturbances in a set of 1° × 1° blocks. The spherical terrain correction, a residual correction to each Bouguer shell, is computed using rock heights and ice sheet thicknesses from the DTM2006 and Earth2014 models. The study illustrates that the defined simple Bouguer gravity disturbance corrected for the density variations of the oceans, ice sheets and sediment basins and also the non-isostatic effects needs a significant terrain correction to become the refined Bouguer gravity disturbance, and that the isostatic gravity disturbance is significantly better defined by the latter disturbance plus a compensation attraction. Our study shows that despite the fact that the lateral variation of the crustal depth is rather smooth, the terrain affects the result most significantly in many areas. The global numerical results show that the estimated Moho depths by the simple and refined spherical Bouguer gravity disturbances and the seismic CRUST1.0 model agree to 5.6 and 2.7 km in RMS, respectively. Also, the mean value differences are 1.7 and 0.2 km, respectively. Two regional numerical studies show that the RMS differences between the Moho depths estimated based on the simple and refined spherical Bouguer gravity disturbance and that using CRUST1.0 model yield fits of 4.9 and 3.2 km in South America and yield 3.2 and 3.4 km in Fennoscandia, respectively.

  12. Plumes in the mantle. [free air and isostatic gravity anomalies for geophysical interpretation

    NASA Technical Reports Server (NTRS)

    Khan, M. A.

    1973-01-01

    Free air and isostatic gravity anomalies for the purposes of geophysical interpretation are presented. Evidence for the existance of hotspots in the mantle is reviewed. The prosposed locations of these hotspots are not always associated with positive gravity anomalies. Theoretical analysis based on simplified flow models for the plumes indicates that unless the frictional viscosities are several orders of magnitude smaller than the present estimates of mantle viscosity or alternately, the vertical flows are reduced by about two orders of magnitude, the plume flow will generate implausibly high temperatures.

  13. Isostatic gravity map of the Monterey 30 x 60 minute quadrangle and adjacent areas, California

    USGS Publications Warehouse

    Langenheim, V.E.; Stiles, S.R.; Jachens, R.C.

    2002-01-01

    The digital dataset consists of one file (monterey_100k.iso) containing 2,385 gravity stations. The file, monterey_100k.iso, contains the principal facts of the gravity stations, with one point coded per line. The format of the data is described below. Each gravity station has a station name, location (latitude and longitude, NAD27 projection), elevation, and an observed gravity reading. The data are on the IGSN71 datum and the reference ellipsoid is the Geodetic Reference System 1967 (GRS67). The free-air gravity anomalies were calculated using standard formulas (Telford and others, 1976). The Bouguer, curvature, and terrain corrections were applied to the free-air anomaly at each station to determine the complete Bouguer gravity anomalies at a reduction density of 2.67 g/cc. An isostatic correction was then applied to remove the long-wavelength effect of deep crustal and/or upper mantle masses that isostatically support regional topography.

  14. Comparisons of global topographic/isostatic models to the Earth's observed gravity field

    NASA Technical Reports Server (NTRS)

    Rummel, Reiner; Rapp, Richard H.; Suenkel, Hans; Tscherning, C. Christian

    1988-01-01

    The Earth's gravitational potential, as described by a spherical harmonic expansion to degree 180, was compared to the potential implied by the topography and its isostatic compensation using five different hypothesis. Initially, series expressions for the Airy/Heiskanen topographic isostatic model were developed to the third order in terms of (h/R), where h is equivalent rock topography and R is a mean Earth radius. Using actual topographic developments for the Earth, it was found that the second and third terms of the expansion contributed 30 and 3 percents, of the first of the expansion. With these new equations it is possible to compute depths (D) of compensation, by degree, using 3 different criteria. The results show that the average depth implied by criterion I is 60 km while it is about 33 km for criteria 2 and 3 with smaller compensation depths at the higher degrees. Another model examined was related to the Vening-Meinesz regional hypothesis implemented in the spectral domain. Finally, oceanic and continental response functions were derived for the global data sets and comparisons made to locally determined values.

  15. Theory of supersymmetry ``protected'' topological phases of isostatic lattices and highly frustrated magnets

    NASA Astrophysics Data System (ADS)

    Lawler, Michael

    I generalize the theory of phonon topological band structures of isostatic lattices to highly frustrated antiferromagnets. I achieve this with a discovery of a many-body supersymmetry (SUSY) in the phonon problem of balls and springs which also applies to geometrically frustrated magnets. The Witten index of the SUSY model, when restricted to the single body problem (meaningful for linearized phonons), is then shown to be the Calladine-Kane-Lubensky index of mechanical structures that forms the cornerstone of the phonon topological band structure theory. ``Spontaneous supersymmetry breaking'' is then identified as the need to gap all modes in the bulk to create the topological state. The many-body SUSY formulation shows that the topology is not restricted to a band structure problem but extends to systems of coupled bosons and fermions that are in principle also realizable in solid state systems. The analogus supersymmetry of the magnon problem turns out to be particularly useful for highly frustrated magnets with the kagome family of antiferromagnets an analog of topological isostatic lattices. Thus, a solid state realization of the theory of phonon topological band structure may be found in highly frustrated magnets. However, our results show that this topology is protected not

  16. A Conversation with Frank Press

    NASA Astrophysics Data System (ADS)

    Goodstein, Judith R.

    Geophysicist Frank Press was director of Caltech's Seismological Laboratory from 1957 to 1965. In this interview, he recalls his work with Maurice Ewing at Columbia's Lamont Geological Observatory; his directorship of Caltech's Seismological Laboratory and colleagues Charles Richter, Beno Gutenberg, and Hugo Benioff; his work on the free oscillations of the earth; and his part in establishing the worldwide network of seismographs for the detection of nuclear weapons testing.

  17. Radial Electromagnetic Press for IGNITOR

    NASA Astrophysics Data System (ADS)

    Cucchiaro, A.; Anzidei, L.; Capriccioli, A.; Celentano, G.; Crescenzi, C.; Gasparotto, M.; Guerrieri, A.; Pizzuto, A.; Palmieri, A.; Rita, C.; Roccella, M.; Coppi, B.

    1998-11-01

    The structural performance of the IGNITOR machine relies upon a combination of both bucking between Toroidal Field Coils (TFCs), Central Solenoid (CS) and the Central Post (CP), and wedging in a well-defined area of the TFCs and of the magnet mechanical structure (called C-Clamps). This requires a pre-loading system to enhance the load bearing capability. Several solutions have been assessed and compared with each other within the operational scenarios and eventually a radial electromagnetic press has been selected as reference(Pizzuto A. et al., ENEA Report IGN/MAC/001/96). The loading system is made up by active coils and passive restraining rings. The radial active press consists of two pairs of coils (200x200mm each), symmetrically located relative to the machine equatorial plane and seating onto the passive rings. The permanent pre--load of the rings is applied through a wedging system with a load of about 120 MN. A radial electromagnetic press has the purpose of modulating the axial pressure on the TFC inner legs during the pulse. Design aspects including stress analysis, manufacturing, assembly and operational scenarios of the selected solution are presented in this paper.

  18. The Small Book Press: A Cultural Essential.

    ERIC Educational Resources Information Center

    Henderson, Bill

    1984-01-01

    Discussion of small literary book publishers notes works of small-press authors (Thomas Paine, Washington Irving, Walt Whitman, Mark Twain, Upton Sinclair, Anais Nin); today's outstanding presses (Creative Arts Book Company, Persea Books, Full Court Press, Reed and Cannon Company, Tuumba Books); and role of little magazines. Thirty-seven…

  19. Yale University Press: Disseminating "Lux et Veritas"?

    ERIC Educational Resources Information Center

    Parrott, John B.

    2010-01-01

    America's university presses are situated within a network of over one hundred universities, learned societies, and scholarly associations. According to a pamphlet put out by the American Association of University Presses, these presses "make available to the broader public the full range and value of research generated by university faculty."…

  20. The Burger Court and the Press.

    ERIC Educational Resources Information Center

    Higdon, Philip R.

    This report discusses recent cases involving freedom of the press that have been heard before the Burger court of the United States Supreme Court. The report discerns a trend toward treating the press like an ordinary citizen; this is a reversal of the view of the Warren court that the First Amendment creates special rights for the press so that…

  1. Regional anomalies of sediment thickness, basement depth and isostatic crustal thickness in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Louden, Keith E.; Tucholke, Brian E.; Oakey, Gordon N.

    2004-07-01

    We calculate the anomalous basement topography for the North Atlantic Ocean from 30° to 70°N latitude and from 0° to 70°W longitude at a resolution of roughly 6×6 km, using grids of total sediment thickness and observed and predicted sea-floor bathymetry to correct for the effects of isostatic sediment loading and lithospheric age. Plotting this residual topography for various plate reconstructions during opening of the North Atlantic, we delineate consistent patterns of basement highs related to variations in hotspot-related volcanism. In addition to Iceland and the Azores, we recognize three centers of excess volcanism at the mid-Atlantic ridge: the Milne Seamounts and Azores-Biscay Rise (˜75-40 Ma), the Southeast Newfoundland Ridge and Madeira-Tore Rise (˜130-110 Ma), and the East and West Thulean Rises (˜60-50 Ma). The duration of volcanic activity ranges from 8 to 10 m.y. (Thulean Rises) to 60 m.y. (Iceland) and thus it appears that both long- and short-lived hotspots coexist, even in relatively close proximity. In contrast, during the period 110-60 Ma we observe little excess volcanism during either continental breakup or seafloor spreading. We estimate isostatic crustal thickness from the anomalous basement depths, after first removing dynamic effects created by mantle flow. Maximum thicknesses of volcanic features, from 30 km beneath the Greenland-Iceland-Faeroe ridge to ˜15 km beneath the Azores-Biscay Rise, are broadly consistent with seismic data and predictions of decompression melting. Widths of volcanic features indicate that thickening primarily occurs within 100-200 km of hotspots except along continental margins that rifted at the time of the hotspot activity (i.e. East Greenland and the Hatton-Rockall Bank). We observe conjugate structures south of Greenland and Edoras Bank, where excess volcanism appears to have extended beyond the margin proper and into oceanic crust. Similar conjugate features appear in the Labrador Sea south of Davis

  2. The influence of high thermal gradient casting, hot isostatic pressing and alternate heat treatment on the structure and properties of a single crystal nickel base superalloy

    NASA Technical Reports Server (NTRS)

    Fritzemeier, L. G.

    1988-01-01

    A development program has been conducted to improve the cyclic properties of the PWA 1480 single-crystal superalloy by reducing or entirely eliminating casting porosity at fatigue-initiation sites, through the use of improved casting process parameters and HIPing; potential mechanical property improvements in a high-pressure hydrogen environment were also sought in alternatives to the standard coating and heat-treatment cycle. High thermal gradient casting was found to yield a reduction in overall casting porosity density and pore sizes. The most dramatic mechanical property improvement resulted from HIPing.

  3. Isostatic uplift, crustal attenuation, and the evolution of an extensional detachment system in southwestern Nevada

    SciTech Connect

    Scott, R.B.

    1987-12-31

    Geological and geophysical evidence supports the existence of extensional detachments, between the Sheep Range and Death Valley. It is proposed that geographically separated pieces of detachments between Death Valley and the Sheep Range are parts of a regional detachment system that has evolved since the Miocene, and that the system consists of lenses of strata separated by an anastomosing network of low- and high-angle normal faults. This manuscript emphasizes the probability that isostatic uplift within the region of greatest crustal attenuation in this system, the Bullfrog Hills core complex, controlled the evolution of the detachment system between the breakaway zone a the Sheep Range and the core complex. Features in this system are described from east to west, which is the apparent direction of tectonic transport.

  4. An isostatic study of the Karoo basin and underlying lithosphere in 3-D

    NASA Astrophysics Data System (ADS)

    Scheiber-Enslin, Stephanie E.; Ebbing, Jörg; Webb, Susan J.

    2016-08-01

    A 3-D density model of the crust and upper mantle beneath the Karoo basin is presented here. The model is constrained using potential field, borehole and seismic data. Uplift of the basin by the end of the Cretaceous has resulted in an unusually high plateau (>1000 m) covering a large portion of South Africa. Isostatic studies show the topography is largely compensated by changes in Moho depths (˜35 km on-craton and >45 km off-craton) and changes in lithospheric mantle densities between the Kaapvaal Craton and surrounding regions (˜50 kg m-3 increase from on- to off-craton). This density contrast is determined by inverted satellite gravity and gravity gradient data. The highest topography along the edge of the plateau (>1200 m) and a strong Bouguer gravity low over Lesotho, however, can only be explained by a buoyant asthenosphere with a density decrease of around 40 kg m-3.

  5. Glacial isostatic adjustment using GNSS permanent stations and GIA modelling tools

    NASA Astrophysics Data System (ADS)

    Kollo, Karin; Spada, Giorgio; Vermeer, Martin

    2013-04-01

    Glacial Isostatic Adjustment (GIA) affects the Earth's mantle in areas which were once ice covered and the process is still ongoing. In this contribution we focus on GIA processes in Fennoscandian and North American uplift regions. In this contribution we use horizontal and vertical uplift rates from Global Navigation Satellite System (GNSS) permanent stations. For Fennoscandia the BIFROST dataset (Lidberg, 2010) and North America the dataset from Sella, 2007 were used respectively. We perform GIA modelling with the SELEN program (Spada and Stocchi, 2007) and we vary ice model parameters in space in order to find ice model which suits best with uplift values obtained from GNSS time series analysis. In the GIA modelling, the ice models ICE-5G (Peltier, 2004) and the ice model denoted as ANU05 ((Fleming and Lambeck, 2004) and references therein) were used. As reference, the velocity field from GNSS permanent station time series was used for both target areas. Firstly the sensitivity to the harmonic degree was tested in order to reduce the computation time. In the test, nominal viscosity values and pre-defined lithosphere thicknesses models were used, varying maximum harmonic degree values. Main criteria for choosing the suitable harmonic degree was chi-square fit - if the error measure does not differ more than 10%, then one might use as well lower harmonic degree value. From this test, maximum harmonic degree of 72 was chosen to perform calculations, as the larger value did not significantly modify the results obtained, as well the computational time for observations was kept reasonable. Secondly the GIA computations were performed to find the model, which could fit with highest probability to the GNSS-based velocity field in the target areas. In order to find best fitting Earth viscosity parameters, different viscosity profiles for the Earth models were tested and their impact on horizontal and vertical velocity rates from GIA modelling was studied. For every

  6. The Indian Ocean gravity low - Evidence for an isostatically uncompensated depression in the upper mantle

    NASA Technical Reports Server (NTRS)

    Ihnen, S. M.; Whitcomb, J. H.

    1983-01-01

    The broad gravity low in the equatorial Indian Ocean south of Sri Lanka is the largest and most striking feature in the gravitational field of the earth. The most negative long-wavelength free-air gravity anomalies are found there and the sea surface (geoid) lies more than 100 meters below the best fitting ellipsoid. A model of the lithosphere and upper mantle is proposed which accurately predicts the observed free-air gravity and geoid elevation. This model is consistent with bathymetry and sediment thickness data and suggests that the crust south of India currently floats as much as 600 meters lower than would be expected if the region were isostatically compensated. This residual depression of the crust is apparently confirmed by observations of ocean depth. An uncompensated depression is consistent with the presence of a mechanical wake left in the upper mantle behind India as it traveled toward Asia.

  7. Modelling the Laurentide Ice Sheet using improved ice margin chronologies and glacio-isostatic observations

    NASA Astrophysics Data System (ADS)

    Gowan, Evan; Tregoning, Paul; Purcell, Anthony; Lambeck, Kurt

    2013-04-01

    Creating models of the Laurentide ice sheet is challenging, due to the deficiency of chronological constraints and the uneven spatial resolution of data to determine the evolution of the glacio-isostatic response after deglaciation. Previous models relied on uncalibrated radiocarbon constrained margins that proved to have deficiencies in recent studies. Additionally, many recent Laurentide ice sheet models have been developed by incorporating climatic parameters that are poorly resolved for the late glacial period. We present a new ice sheet model by an iterative process of changing basal shear stress values and ice sheet margin location. A particular focus of this study is to determine the thickness and extent of the western Laurentide ice sheet, where there were few well dated observations of glacio-isostatic motion until recently. The volume of an ice sheet during long periods depends mostly on basal shear stress and margin position, which are the main parameters that we vary to fit our model to glacio-isostatic observations. We build our ice model using the assumption of perfectly plastic, steady-state conditions, with variable basal shear stress. Basal shear stress values depend on the surficial geology underlying the ice, and are at a minimum in offshore regions that have soft, deformable sediments, and at a maximum in areas with exposed crystalline bedrock. This approach may not capture dynamic and short lived features of the ice sheet, such as ice streams and stagnant ice, but gives an approximation of average conditions to produce ice volumes that fit geophysical observations. We adjust the margin location when the shear stress conditions alone cannot account for the observed glacio-isostatic response. The constraints on the response include relative sea level benchmarks, sea level highstand positions and proglacial lakes. We repeat the analysis using different rheological profiles to determine the dependence the Earth model has on the estimation of ice

  8. Incomplete separability of Antarctic plate rotation from glacial isostatic adjustment deformation within geodetic observations

    NASA Astrophysics Data System (ADS)

    King, Matt A.; Whitehouse, Pippa L.; van der Wal, Wouter

    2016-01-01

    Geodetic measurements of Antarctic solid Earth deformation include signals from plate rotation and glacial isostatic adjustment (GIA). Through simulation, we investigate the degree to which these signals are separable within horizontal GPS site velocities that commonly define plate rotation estimates and that promise new constraints on models of GIA. Using a suite of GIA model predictions that incorporate both 1-D and 3-D Earth rheologies, we show that, given the present location of GPS sites within East Antarctica, unmodelled or mismodelled GIA signal within GPS velocities produces biased estimates of plate rotation. When biased plate rotation is removed from the GPS velocities, errors as large as 0.8 mm yr-1 are introduced; a value commonly larger than the predicted GIA signal magnitude. In the absence of reliable forward models of plate rotation or GIA then Antarctic geodetic velocities cannot totally and unambiguously constrain either process, especially GIA.

  9. Preliminary isostatic gravity map of the Sonoma volcanic field and vicinity, Sonoma and Napa Counties, California

    USGS Publications Warehouse

    Langenheim, V.E.; Roberts, C.W.; McCabe, C.A.; McPhee, D.K.; Tilden, J.E.; Jachens, R.C.

    2006-01-01

    This isostatic residual gravity map is part of a three-dimensional mapping effort focused on the subsurface distribution of rocks of the Sonoma volcanic field in Napa and Sonoma counties, northern California. This map will serve as a basis for modeling the shapes of basins beneath the Santa Rosa Plain and Napa and Sonoma Valleys, and for determining the location and geometry of faults within the area. Local spatial variations in the Earth's gravity field (after accounting for variations caused by elevation, terrain, and deep crustal structure explained below) reflect the distribution of densities in the mid to upper crust. Densities often can be related to rock type, and abrupt spatial changes in density commonly mark lithologic boundaries. High-density basement rocks exposed within the northern San Francisco Bay area include those of the Mesozoic Franciscan Complex and Great Valley Sequence present in the mountainous areas of the quadrangle. Alluvial sediment and Tertiary sedimentary rocks are characterized by low densities. However, with increasing depth of burial and age, the densities of these rocks may become indistinguishable from those of basement rocks. Tertiary volcanic rocks are characterized by a wide range in densities, but, on average, are less dense than the Mesozoic basement rocks. Isostatic residual gravity values within the map area range from about -41 mGal over San Pablo Bay to about 11 mGal near Greeg Mountain 10 km east of St. Helena. Steep linear gravity gradients are coincident with the traces of several Quaternary strike-slip faults, most notably along the West Napa fault bounding the west side of Napa Valley, the projection of the Hayward fault in San Pablo Bay, the Maacama Fault, and the Rodgers Creek fault in the vicinity of Santa Rosa. These gradients result from juxtaposing dense basement rocks against thick Tertiary volcanic and sedimentary rocks.

  10. Heinrich events driven by feedback between ocean forcing and glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Bassis, J. N.; Petersen, S. V.; Cathles, L. M. M., IV

    2015-12-01

    One of the most puzzling glaciological features of the past ice age is the episodic discharge of large volumes of icebergs from the Laurentide Ice Sheet, known as Heinrich events. It has been suggested that Heinrich events are caused by internal instabilities in the ice sheet (e.g. the binge-purge oscillation). A purely ice dynamic cycle, however, is at odds with the fact that every Heinrich event occurs during the cold phase of a DO cycle, implying some regional climate connection. Recent work has pointed to subsurface water warming as a trigger for Heinrich events through increased basal melting of an ice shelf extending across the Hudson Strait and connecting with the Greenland Ice Sheet. Such a large ice shelf, spanning the deepest part of the Labrador Sea, has no modern analog and limited proxy evidence. Here we use a width averaged "flowline" model of the Hudson Strait ice stream to show that Heinrich events can be triggered by ocean forcing of a grounded terminus without the need for an ice shelf. At maximum ice extent, bed topography is depressed and the terminus is more sensitive to a subsurface thermal forcing. Once triggered, the retreat is rapid, and continues until isostatic rebound of the bed causes local sea level to drop sufficiently to arrest retreat. Topography slowly rebounds, decreasing the sensitivity to ocean forcing and the ice stream re-advances at a rate that is an order of magnitude slower than collapse. This simple feedback cycle between a short-lived ocean trigger and slower isostatic adjustment can reproduce the periodicity and timing of observed Heinrich events under a range of glaciological and solid earth parameters. Our results suggest that not only does the solid Earth play an important role in regulating ice sheet stability, but that grounded marine terminating portions of ice sheets may be more sensitive to ocean forcing than previously thought.

  11. Insights into the Crustal Structure and Geodynamic Evolution of the Southern Granulite Terrain, India, from Isostatic Considerations

    NASA Astrophysics Data System (ADS)

    Kumar, Niraj; Singh, A. P.; Singh, B.

    2011-10-01

    The Southern Granulite Terrain of India, formed through an ancient continental collision and uplift of the earth's surface, was accompanied by thickening of the crust. Once the active tectonism ceased, the buoyancy of these deep crustal roots must have supported the Nilgiri and Palani-Cardamom hills. Here, the gravity field has been utilized to provide new constraints on how the force of buoyancy maintains the state of isostasy in the Southern Granulite Terrain. Isostatic calculations show that the seismically derived crustal thickness of 43-44 km in the Southern Granulite Terrain is on average 7-8 km more than that required to isostatically balance the present-day topography. This difference cannot be solely explained applying a constant shift in the mean sea level crustal thickness of 32 km. The isostatic analysis thus indicates that the current topography of the Southern Granulite Terrain is overcompensated, and about 1.0 km of the topographic load must have been eroded from this region without any isostatic readjustment. The observed gravity anomaly, an order of magnitude lower than that expected (-125 mGal), however, shows that there is no such overcompensation. Thermal perturbations up to Pan-African, present-day high mantle heat flow and low Te together negate the possible resistance of the lithosphere to rebound in response to erosional unloading. To isostatically compensate the crustal root, compatible to seismic Moho, a band of high density (2,930 kg m-3) in the lower crust and low density (3,210 kg m-3) in the lithospheric mantle below the Southern Granulite Terrain is needed. A relatively denser crust due to two distinct episodes of metamorphic phase transitions at 2.5 Ga and 550 Ma and highly mobilized upper mantle during Pan-African thermal perturbation reduced significantly the root buoyancy that kept the crust pulled downward in response to the eroded topography.

  12. Cold press sintering of simulated lunar basalt

    NASA Technical Reports Server (NTRS)

    Altemir, D. A.

    1993-01-01

    In order to predict the conditions for which the lunar regolith may be adequately sintered, experiments were conducted in which samples of simulated lunar basalt (MLS-1) were pressed at high pressures and then heated in an electric furnace. This sintering process may be referred to as cold press sintering since the material is pressed at room temperature. Although test articles were produced which possessed compressive strengths comparable to that of terrestrial concrete, the cold press sintering process requires very high press pressures and sintering temperatures in order to achieve that strength. Additionally, the prospect of poor internal heat transfer adversely affecting the quality of sintered lunar material is a major concern. Therefore, it is concluded that cold press sintering will most likely be undesirable for the production of lunar construction materials.

  13. Slurry-pressing consolidation of silicon nitride

    NASA Technical Reports Server (NTRS)

    Sanders, William A.; Kiser, James D.; Freedman, Marc R.

    1989-01-01

    A baseline slurry-pressing method for a silicon nitride material is developed. The Si3N4 composition contained 5.8 wt percent SiO2 and 6.4 wt percent Y2O3. Slurry-pressing variables included volume percent solids, application of ultrasonic energy, and pH. Twenty vol percent slurry-pressed material was approximately 11 percent stronger than both 30 vol percent slurry-pressed and dry-pressed materials. The Student's t-test showed the difference to be significant at the 99 percent confidence level. Twenty volume percent (300 h) slurry-pressed test bars exhibited strengths as high as 980 MPa. Large, columnar beta-Si3N4 grains caused failure in the highest strength specimens. The improved strength correlated with better structural uniformity as determined by radiography, optical microscopy, and image analysis.

  14. Slurry-pressing consolidation of silicon nitride

    NASA Technical Reports Server (NTRS)

    Sanders, William A.; Kiser, James D.; Freedman, Marc R.

    1988-01-01

    A baseline slurry-pressing method for a silicon nitride material is developed. The Si3N4 composition contained 5.8 wt percent SiO2 and 6.4 wt percent Y2O3. Slurry-pressing variables included volume percent solids, application of ultrasonic energy, and pH. Twenty vol percent slurry-pressed material was approximately 11 percent stronger than both 30 vol percent slurry-pressed and dry-pressed materials. The Student's t-test showed the difference to be significant at the 99 percent confidence level. Twenty volume percent (300 h) slurry-pressed test bars exhibited strengths as high as 980 MPa. Large, columnar beta-Si3N4 grains caused failure in the highest strength specimens. The improved strength correlated with better structural uniformity as determined by radiography, optical microscopy, and image analysis.

  15. NASA/MSFC Large Stretch Press Study

    NASA Technical Reports Server (NTRS)

    Choate, M. W.; Nealson, W. P.; Jay, G. C.; Buss, W. D.

    1985-01-01

    The purpose of this study was to: A. assess and document the advantages/disadvantages of a government agency investment in a large stretch form press on the order of 5000 tons capacity (per jaw); B. develop a procurement specification for the press; and C. provide trade study data that will permit an optimum site location. Tasks were separated into four major elements: cost study, user survey, site selection, and press design/procurement specification.

  16. [The press and family planning].

    PubMed

    Abraham De D'ornellas, R

    1987-01-01

    The treatment in the press of family planning hinges on two fundamental factors: the taboo of the leftist groups and the taboo of the Catholic Church, whose head is against abortion under any circumstances. Leftist views insinuate that family planning is the genocidal plan of North American imperialists against the Third World and, in particular, against Latin America. This genocidal plan is supposed to subject poor populations to international schemes. In the press family planning is often treated in a sanctimonious fashion, lumping it together with topics like pornography, sex, and violence. In 1983 the daily newspaper Expreso published a supplement running every week for almost three months about the issue of population, which dealt fairly extensively with such topics as population and housing, education, employment, and urban proliferation, as well as responsible parenthood and child survival. In addition, there was a detailed description of contraceptive methods. In October 1986 another surprising thing happened: the President of Peru talked about the topic of family planning, which at the time was an act of courage. Since then much has changed; the whole world is interested in family planning and certain aspects of population. Since October 1986 more has been published in this domain than during the preceding 20 years. In contrast, the Church reacted differently to this issue: after some initial caution, the conference of Peruvian bishops attacked all methods of modern contraceptives and private institutions of family planning. The information boom in family planning will certainly continue. At the moment this flood of articles and editorials about the issue is an expression of the anxiety of families related to uncontrolled reproduction and the fear of overpopulation in large cities devoid of minimal services. PMID:12281466

  17. Anomalous secular sea-level acceleration in the Baltic Sea caused by glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Spada, Giorgio; Galassi, Gaia; Olivieri, Marco

    2014-05-01

    Observations from the global array of tide gauges show that global sea-level has been rising at an average rate of 1.5-2 mm/yr during the last ˜ 150 years (Spada & Galassi, 2012). Although a global sea-level acceleration was initially ruled out, subsequent studies have coherently proposed values of ˜1 mm/year/century (Olivieri & Spada, 2012). More complex non-linear trends and abrupt sea-level variations have now also been recognized. Globally, they could manifest a regime shift between the late Holocene and the current rhythms of sea-level rise, while locally they result from ocean circulation anomalies, steric effects and wind stress (Bromirski et al. 2011). Although isostatic readjustment affects the local rates of secular sea-level change, a possible impact on regional acceleration have been so far discounted (Woodworth et al., 2009) since the process evolves on a millennium scale. Here we report a previously unnoticed anomaly in the long-term sea-level acceleration of the Baltic Sea tide gauge records, and we explain it by the classical post-glacial rebound theory and numerical modeling of glacial isostasy. Contrary to previous assumptions, our findings demonstrate that isostatic compensation plays a role in the regional secular sea-level acceleration. In response to glacial isostatic adjustment (GIA), tide gauge records located along the coasts of the Baltic Sea exhibit a small - but significant - long-term sea-level acceleration in excess to those in the far field of previously glaciated regions. The sign and the amplitude of the anomaly is consistent with the post-glacial rebound theory and with realistic numerical predictions of GIA models routinely employed to decontaminate the tide gauges observations from the GIA effects (Peltier, 2004). Model computations predict the existence of anomalies of similar amplitude in other regions of the globe where GIA is still particularly vigorous at present, but no long-term instrumental observations are available to

  18. The Press vs. Professional Wrestling: How the Press Covered WrestleMania III.

    ERIC Educational Resources Information Center

    Ortizano, Giacomo L.

    This paper analyzes the relationship between the press and professional wrestling. It examines professional wrestling as a business and the conflicting goals of the promoters and the press. The paper focuses on how the press covered the most widely viewed professional wrestling show of all time, WrestleMania III (looking at newspaper coverage…

  19. Preliminary Isostatic Gravity Map of Joshua Tree National Park and Vicinity, Southern California

    USGS Publications Warehouse

    Langenheim, V.E.; Biehler, Shawn; McPhee, D.K.; McCabe, C.A.; Watt, J.T.; Anderson, M.L.; Chuchel, B.A.; Stoffer, P.

    2007-01-01

    This isostatic residual gravity map is part of an effort to map the three-dimensional distribution of rocks in Joshua Tree National Park, southern California. This map will serve as a basis for modeling the shape of basins beneath the Park and in adjacent valleys and also for determining the location and geometry of faults within the area. Local spatial variations in the Earth's gravity field, after accounting for variations caused by elevation, terrain, and deep crustal structure, reflect the distribution of densities in the mid- to upper crust. Densities often can be related to rock type, and abrupt spatial changes in density commonly mark lithologic or structural boundaries. High-density basement rocks exposed within the Eastern Transverse Ranges include crystalline rocks that range in age from Proterozoic to Mesozoic and these rocks are generally present in the mountainous areas of the quadrangle. Alluvial sediments, usually located in the valleys, and Tertiary sedimentary rocks are characterized by low densities. However, with increasing depth of burial and age, the densities of these rocks may become indistinguishable from those of basement rocks. Tertiary volcanic rocks are characterized by a wide range of densities, but, on average, are less dense than the pre-Cenozoic basement rocks. Basalt within the Park is as dense as crystalline basement, but is generally thin (less than 100 m thick; e.g., Powell, 2003). Isostatic residual gravity values within the map area range from about 44 mGal over Coachella Valley to about 8 mGal between the Mecca Hills and the Orocopia Mountains. Steep linear gravity gradients are coincident with the traces of several Quaternary strike-slip faults, most notably along the San Andreas Fault bounding the east side of Coachella Valley and east-west-striking, left-lateral faults, such as the Pinto Mountain, Blue Cut, and Chiriaco Faults (Fig. 1). Gravity gradients also define concealed basin-bounding faults, such as those beneath the

  20. Optimal locations of sea-level indicators in glacial isostatic adjustment investigations

    NASA Astrophysics Data System (ADS)

    Steffen, Holger; Wu, Patrick; Wang, Hansheng

    2015-04-01

    This poster presents the results of Steffen et al. (2014). Fréchet (sensitivity) kernels are an important tool in glacial isostatic adjustment (GIA) investigations to understand lithospheric thickness, mantle viscosity and ice-load model variations. These parameters influence the interpretation of geologic, geophysical and geodetic data, which contribute to our understanding of global change. We discuss global sensitivities of relative sea-level (RSL) data of the last 18 000 years. This also includes indicative RSL-like data (e.g., lake levels) on the continents far off the coasts. We present detailed sensitivity maps for four parameters important in GIA investigations (ice-load history, lithospheric thickness, background viscosity, lateral viscosity variations) for up to nine dedicated times. Assuming an accuracy of 2 m of RSL data of all ages (based on analysis of currently available data), we highlight areas around the world where, if the environmental conditions allowed its deposition and survival until today, RSL data of at least this accuracy may help to quantify the GIA modeling parameters above. The sensitivity to ice-load history variations is the dominating pattern covering almost the whole world before about 13 ka (calendar years before 1950). The other three parameters show distinct patterns, but are almost everywhere overlapped by the ice-load history pattern. The more recent the data are, the smaller the area of possible RSL locations that could provide enough information to a parameter. Such an area is mainly limited to the area of former glaciation, but we also note that when the accuracy of RSL data can be improved, e.g., from 2 m to 1 m, these areas become larger, allowing better inference of background viscosity and lateral heterogeneity. Although the patterns depend on the chosen models and error limit, our results are indicative enough to outline areas where one should look for helpful RSL data of a certain time period. Our results also

  1. Teenagers as Victims in the Press

    ERIC Educational Resources Information Center

    Andersson, Gunvor; Lundstrom, Tommy

    2007-01-01

    Research into press reporting on young people has tended to concentrate on young people as offenders. In contrast, this article focuses on press coverage of teenagers as victims. Reports in two Swedish newspapers (a morning broadsheet and an evening tabloid) were studied over a period of four months and subjected to a qualitative analysis of…

  2. Special Section: University Presses and Libraries.

    ERIC Educational Resources Information Center

    Berry, John; And Others

    1986-01-01

    Describes issues discussed at the Association of American University Presses, June 1986 meeting, as being divided between those interested in using the techniques of commercial publishers and those committed to publishing what is worthy. Chandler Grannis describes "New Directions for University Presses" and Doug Armato "The Power of 'Serious'…

  3. The Lily-White University Presses.

    ERIC Educational Resources Information Center

    Shin, Annys

    1996-01-01

    Argues that the university presses are immune from racial change and discusses the problem of using location as an argument for not being able to lure blacks into university publishing. Howard University Press is used to illustrate the problem of budget cutting and the ability to boost black recruitment efforts or establish a united black press…

  4. The Mythology of the Penny Press.

    ERIC Educational Resources Information Center

    Nerone, John C.

    1987-01-01

    Examines common scholarly characterizations of the American penny press of the 1830s and 40s that together provide a myth of origins of the contemporary U.S. press. Criticizes inaccuracies and misleading elements in this mythology and its implications for subsequent debate about U.S. journalism. (JK)

  5. The Egyptian Press: An Official Fourth Estate.

    ERIC Educational Resources Information Center

    Lawhorne, Clifton O.

    A descriptive study based on Egyptian law, printed sources, and interviews clarifies our picture of the Egyptian Press by examining its status as a constitutionally mandated "Fourth Estate." The constitutional amendment, the resultant Egyptian Press Law, and the "Law Of Shame" (all passed in 1980), are designed to create a heavily controlled press…

  6. Freedom of the Press vs. Public Access.

    ERIC Educational Resources Information Center

    Schmidt, Benno C., Jr.

    This book surveys the implications of freedom of the press for a constitutionally rooted public right of access to electronic and print media. Part one provides general perspectives on access to the media, including discussions of access in relation to the Supreme Court, to First Amendment history and theory, to current perceptions of the press,…

  7. Fracture toughness of hot-pressed beryllium

    NASA Technical Reports Server (NTRS)

    Lemon, D. D.; Brown, W. F., Jr.

    1985-01-01

    This paper presents the results of an investigation into the fracture toughness, sustained-load flaw growth, and fatigue-crack propagation resistance of S200E hot-pressed beryllium at room temperature. It also reviews the literature pertaining to the influence of various factors on the fracture toughness of hot-pressed beryllium determined using fatigue-cracked specimens.

  8. The Pedagogical Press: Problems and Trends.

    ERIC Educational Resources Information Center

    Soviet Education, 1990

    1990-01-01

    Presents a discussion by journalists, scientists, and writers on educational problems in the Soviet Union. Focuses on the the role of the pedagogical press in restructuring public education in light of perestroika. Calls for press involvement in defining and developing public education. Lists questions for consideration and invites responses. (NL)

  9. The Reluctant Reformation: On Criticizing the Press in America.

    ERIC Educational Resources Information Center

    Brown , Lee

    This book examines the status of the press and the criticism surrounding it. Chapter 1 attempts to relate theories of criticism to the contemporary press, to define the public interest relative to the press, and to discuss the role of criticism and the social responsibility of the press. Chapter 2 presents a brief history of press criticism from…

  10. Preliminary isostatic residual gravity anomaly map of Paso Robles 30 x 60 minute quadrangle, California

    USGS Publications Warehouse

    McPhee, D.K.; Langenheim, V.E.; Watt, J.T.

    2011-01-01

    This isostatic residual gravity map is part of an effort to map the three-dimensional distribution of rocks in the central California Coast Ranges and will serve as a basis for modeling the shape of basins and for determining the location and geometry of faults within the Paso Robles quadrangle. Local spatial variations in the Earth\\'s gravity field, after accounting for variations caused by elevation, terrain, and deep crustal structure reflect the distribution of densities in the mid- to upper crust. Densities often can be related to rock type, and abrupt spatial changes in density commonly mark lithological or structural boundaries. High-density rocks exposed within the central Coast Ranges include Mesozoic granitic rocks (exposed northwest of Paso Robles), Jurassic to Cretaceous marine strata of the Great Valley Sequence (exposed primarily northeast of the San Andreas fault), and Mesozoic sedimentary and volcanic rocks of the Franciscan Complex [exposed in the Santa Lucia Range and northeast of the San Andreas fault (SAF) near Parkfield, California]. Alluvial sediments and Tertiary sedimentary rocks are characterized by low densities; however, with increasing depth of burial and age, the densities of these rocks may become indistinguishable from those of older basement rocks.

  11. Isostatic Gravity Map of the Battle Mountain 30 x 60 Minute Quadrangle, North Central Nevada

    USGS Publications Warehouse

    Ponce, D.A.; Morin, R.L.

    2000-01-01

    Introduction Gravity investigations of the Battle Mountain 30 x 60 minute quadrangle were begun as part of an interagency effort by the U.S. Geological Survey (USGS) and the Bureau of Land Management to help characterize the geology, mineral resources, hydrology, and ecology of the Humboldt River Basin in north-central Nevada. The Battle Mountain quadrangle is located between 40?30' and 41?N. lat. and 116? and 117?W. long. This isostatic gravity map of the Battle Mountain quadrangle was prepared from data from about 1,180 gravity stations. Most of these data are publicly available on a CD-ROM of gravity data of Nevada (Ponce, 1997) and in a published report (Jewel and others, 1997). Data from about 780 gravity stations were collected by the U.S. Geological Survey since 1996; data from about 245 of these are unpublished (USGS, unpub. data, 1998). Data collected from the 400 gravity stations prior to 1996 are a subset of a gravity data compilation of the Winnemucca 1:250,000-scale quadrangle described in great detail by Wagini (1985) and Sikora (1991). This detailed information includes gravity meters used, dates of collection, sources, descriptions of base stations, plots of data, and a list of principal facts. A digital version of the entire data set for the Battle Mountain quadrangle is available on the World Wide Web at: http://wrgis.wr.usgs.gov/docs/gump/gump.html

  12. Isostatic and dynamic support of high topography on a North Atlantic passive margin

    NASA Astrophysics Data System (ADS)

    Kathrine Pedersen, Vivi; Huismans, Ritske S.; Moucha, Robert

    2016-04-01

    Substantial controversy surrounds the origin and recent evolution of high topography along passive continental margins in the North Atlantic, with suggested age of formation ranging from early Paleozoic Caledonian orogenesis to Neogene uplift of a Mesozoic peneplain. Here we focus on the well-documented high passive margin in southwestern Scandinavia, and quantify the relative contributions of crustal isostasy and dynamic topography in controlling the present topography. We find that most topography is compensated by the crustal structure, suggesting a topographic age related to ~400 Myr old Caledonian orogenesis. In addition, we infer that dynamic uplift (~300 m) has rejuvenated existing topography locally in the coastal region within the last ~10 Myr due to mantle convection. Such uplift has, in combination with a general eustatic sea-level fall and concurrent erosion-driven isostatic rock-column uplift, the potential to increase erosion of coastal-near regions and explain observations that have traditionally been interpreted in favor of the peneplain uplift model. We conclude that high topography along the Scandinavian margin cannot represent remnants of a peneplain uplifted within the last ~20 Myr. Topography must have been high since the Caledonian orogeny.

  13. Rigidity percolation by next-nearest-neighbor bonds on generic and regular isostatic lattices.

    PubMed

    Zhang, Leyou; Rocklin, D Zeb; Chen, Bryan Gin-ge; Mao, Xiaoming

    2015-03-01

    We study rigidity percolation transitions in two-dimensional central-force isostatic lattices, including the square and the kagome lattices, as next-nearest-neighbor bonds ("braces") are randomly added to the system. In particular, we focus on the differences between regular lattices, which are perfectly periodic, and generic lattices with the same topology of bonds but whose sites are at random positions in space. We find that the regular square and kagome lattices exhibit a rigidity percolation transition when the number of braces is ∼LlnL, where L is the linear size of the lattice. This transition exhibits features of both first-order and second-order transitions: The whole lattice becomes rigid at the transition, and a diverging length scale also exists. In contrast, we find that the rigidity percolation transition in the generic lattices occur when the number of braces is very close to the number obtained from Maxwell's law for floppy modes, which is ∼L. The transition in generic lattices is a very sharp first-order-like transition, at which the addition of one brace connects all small rigid regions in the bulk of the lattice, leaving only floppy modes on the edge. We characterize these transitions using numerical simulations and develop analytic theories capturing each transition. Our results relate to other interesting problems, including jamming and bootstrap percolation. PMID:25871071

  14. The sea level fingerprint of 21st Century ice mass loss and Glacial Isostatic Adjustment

    NASA Astrophysics Data System (ADS)

    Riva, R. E.; Bamber, J. L.

    2009-12-01

    The sea level contribution from glacial sources has been accelerating over the last decade. This contribution is not distributed uniformly across the world’s oceans due to both oceanographic and gravitational effects. We compute the sea level signature of 21st Century ice mass fluxes due to changes in the gravity field and Earth’s rotation. The combined pattern of wastage from the largest sources results in maxima of > 1.5 mm/yr at low latitudes across most of the Pacific Ocean, affecting particularly vulnerable land masses. However, sea level changes induced by Glacial Isostatic Adjustment (GIA), representing the viscoelastic deformation of the Solid Earth in response to the past glacial history, are still the dominating signal in many regions, particularly at high latitudes. As a consequence, the instrumental detection of fingerprints requires careful modelling of GIA, which is still subject to large uncertainties. We will compare fingerprints of current melt to those induced by various GIA models, and elaborate on the actual possibility of separating the two signals from the analysis of different datasets.

  15. Late Stage 5 Glacio-isostatic Sea in the St. Lawrence Valley, Canada and United States

    USGS Publications Warehouse

    Occhietti, S.; Balescu, S.; Lamothe, M.; Clet, M.; Cronin, T.; Ferland, P.; Pichet, P.

    1996-01-01

    Although post-glacial marine sediments of late Wisconsinan and early Holocene age are common in eastern Canada and the northeastern United States, remnants of older Pleistocene marine sediments are scarce. A fossiliferous marine clay that predates the classical Wisconsinan was recently discovered in the St. Lawrence Valley. A dominantly estuarine environment is inferred from the geochemistry of the shells (??18O = -7.1) and from benthic foraminifer and ostracode assemblages. The clay indicates a marine invasion (Cartier Sea) shallower and probably shorter than that during the upper late Wisconsinan Champlain Sea episode (12,000-9,500 yr B.P.). The pollen content shows that regional vegetation during the marine episode began as open tundra, then became a Betula and Alnus crispa forest, reached a climatic optimum with Quercus, Corylus, and Abies, and concluded as a Pinus/Picea boreal forest. A corrected infrared stimulated luminescence age of 98,000 ?? 9000 yr is compatible with the epimerization ratio of shells. The Cartier Sea resulted from a post-glacial glacio-isostatic marine invasion in the St. Lawrence lowlands. It probably occurred during late stage 5 and is tentatively assigned to the transition of oxygen isotope substages 5b/5a. This marine episode dates to stage 5 of the preceding continental glacier which extended to middle latitudes in NE America. ?? 1996 University of Washington.

  16. Glacial Isostatic Adjustment in North America Observed by Continuous and Episodic GPS

    NASA Astrophysics Data System (ADS)

    Sella, G. F.; Stein, S.; Wdowinski, S.; Dixon, T. H.; Craymer, M.; James, T.

    2003-12-01

    We use continuous and episodic Global Positioning System (GPS) data to measure the movement caused by glacial isostatic adjustment (GIA) due to glacial unloading in eastern North America. At present it is challenging to quantify GIA motion in North American because of the limited distribution of continuous GPS sites in and around Hudson Bay, the area of maximum glacial loading. In the last two years new continuous GPS sites have been established in Canada, but they are presently of limited use due to their short time series. Episodic GPS sites provide a low cost and higher density alternative, but often have large errors, especially in the vertical. However, the large vertical signal due to GIA (>10mm/yr) in the area of maximum uplift permits this motion to be resolved, even with episodic GPS data. We present data from over 100 continuous GPS sites throughout North America and more than 40 GPS sites of the Canadian Base Network (CBN). The CBN sites located across central and southern Canada have been episodically occupied between 1994 and 2002. We have detected a coherent pattern of vertical motions around the area of maximum glacial loading, Hudson Bay. The observed velocities are initially large and upward, and decrease southward from Hudson Bay to zero, delineating the hinge line near the Great Lakes. The position of the hinge line is in agreement with some numerical GIA predictions. A three-dimensional site velocity distribution may permit assessment of the role of GIA in the seismicity of eastern North America.

  17. Constraints on Glacial Isostatic Adjustment (GIA) Motion in North American Using GPS

    NASA Astrophysics Data System (ADS)

    Sella, G. F.; Stein, S.; Dixon, T.; Craymer, M.; James, T.; Mazzotti, S.

    2005-12-01

    We use continuous and episodic Global Positioning System (GPS) data to measure the motion caused by glacial isostatic adjustment (GIA) due to glacial unloading in eastern North America. The large vertical signal due to GIA (>10mm/yr) in the area of maximum uplift, near Hudson Bay, permits this motion to be resolved with both continuous GPS (CGPS) data and even with episodic GPS (EGPS) data. We present data from 130 CGPS sites throughout North America and almost 100 EGPS sites of the Canadian Base Network (CBN). The CBN sites are located across central and southern Canada and have been episodically occupied between 1994 and 2002. We detect a coherent pattern of vertical motions around the area of maximum glacial loading, Hudson Bay. The observed velocities are initially large and upward, and decrease southward from Hudson Bay to zero, delineating the hinge line near the Great Lakes. The position of the hinge line is in agreement with some numerical GIA predictions. The horizontal residual velocities after removing the motion of the rigid North American plate also show a consistent, but more complex pattern than the vertical velocities. In particular we observe larger than expected motions on the east side of the Canadian Rocky Mountains, possibly reflecting larger ice loads and/or changes in mantle viscosity. We believe that this velocity field provides a comprehensive direct description of GIA motion and can be used to constrain GIA model predictions.

  18. Isostatic Gravity Map with Geology of the Santa Ana 30' x 60' Quadrangle, Southern California

    USGS Publications Warehouse

    Langenheim, V.E.; Lee, Tien-Chang; Biehler, Shawn; Jachens, R.C.; Morton, D.M.

    2006-01-01

    This report presents an updated isostatic gravity map, with an accompanying discussion of the geologic significance of gravity anomalies in the Santa Ana 30 by 60 minute quadrangle, southern California. Comparison and analysis of the gravity field with mapped geology indicates the configuration of structures bounding the Los Angeles Basin, geometry of basins developed within the Elsinore and San Jacinto Fault zones, and a probable Pliocene drainage network carved into the bedrock of the Perris block. Total cumulative horizontal displacement on the Elsinore Fault derived from analysis of the length of strike-slip basins within the fault zone is about 5-12 km and is consistent with previously published estimates derived from other sources of information. This report also presents a map of density variations within pre-Cenozoic metamorphic and igneous basement rocks. Analysis of basement gravity patterns across the Elsinore Fault zone suggests 6-10 km of right-lateral displacement. A high-amplitude basement gravity high is present over the San Joaquin Hills and is most likely caused by Peninsular Ranges gabbro and/or Tertiary mafic intrusion. A major basement gravity gradient coincides with the San Jacinto Fault zone and marked magnetic, seismic-velocity, and isotopic gradients that reflect a discontinuity within the Peninsular Ranges batholith in the northeast corner of the quadrangle.

  19. Glacial isostatic adjustment on the Northern Hemisphere - new results from GRACE

    NASA Astrophysics Data System (ADS)

    Mueller, J.; Steffen, H.; Gitlein, O.; Denker, H.; Timmen, L.

    2007-12-01

    The Earth's gravity field mapped by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. The Earth's gravity field is provided in form of monthly solutions by several institutions, e.~g. GFZ Potsdam, CSR and JPL. During the GRACE standard processing of these analysis centers, oceanic and atmospheric contributions as well as tidal effects are reduced. The solutions of the analysis centers differ slightly, which is due the application of different reduction models and center-specific processing schemes. We present our investigation of mass variations in the areas of glacial isostatic adjustment (GIA) in North America and Northern Europe from GRACE data. One key issue is the separation of GIA parts and the reduction of the observed quantities by applying dedicated filters (e.~g. isotropic, non-isotropic, and destriping filters) and global models of hydrological variations (e.~g. WGHM, LaDWorld, GLDAS). In a further step, we analyze the results of both regions regarding their reliability, and finally present a comparison to results of a geodynamical modeling and absolute gravity measurements. Our results clearly show that the quality of the GRACE-derived gravity- change signal benefits from improved reduction models and chosen analysis techniques. Nevertheless, the comparison to results of geodynamic models still reveals differences, and thus further studies are in progress.

  20. On the gravity and geoid effects of glacial isostatic adjustment in Fennoscandia - a short note

    NASA Astrophysics Data System (ADS)

    Sjöberg, L. E.

    2015-12-01

    Many geoscientists argue that there is a gravity low of 10-30 mGal in Fennoscandia as a remaining fingerprint of the last ice age and load, both vanished about 10 kyr ago. However, the extraction of the gravity signal related with Glacial Isostatic Adjustment (GIA) is complicated by the fact that the total gravity field is caused by many significant density distributions in the Earth. Here we recall a methodology originating with A. Bjerhammar 35 years ago, that emphasizes that the present land uplift phenomenon mainly occurs in the region thatwas covered by the ice cap, and it is highly correlated with the spectral window of degrees 10-22 of the global gravity field, whose lower limit fairly well corresponds to the wavelength that agrees with the size of the region. This implies that, although in principle the GIA is a global phenomenon, the geoid and gravity lows as well as the land upheaval in Fennoscandia are typically regional phenomena that cannot be seen in a global correlation study as it is blurred by many irrelevant gravity signals. It is suggested that a regional multi-regression analysis with a band-limited spectral gravity signal as the observable, a method tested already 2 decades ago, can absorb possible significant disturbing signals, e.g. from topographic and crustal depth variations, and thereby recover the GIA signal.

  1. On the gravity and geoid effects of glacial isostatic adjustment in Fennoscandia - a short note

    NASA Astrophysics Data System (ADS)

    Sjöberg, L. E.

    2016-02-01

    Many geoscientists argue that there is a gravity low of 10-30 mGal in Fennoscandia as a remaining fingerprint of the last ice age and load, both vanished about 10 kyr ago. However, the extraction of the gravity signal related with Glacial Isostatic Adjustment (GIA) is complicated by the fact that the total gravity field is caused by many significant density distributions in the Earth. Here we recall a methodology originating with A. Bjerhammar 35 years ago, that emphasizes that the present land uplift phenomenon mainly occurs in the region thatwas covered by the ice cap, and it is highly correlated with the spectral window of degrees 10-22 of the global gravity field, whose lower limit fairly well corresponds to the wavelength that agrees with the size of the region. This implies that, although in principle the GIA is a global phenomenon, the geoid and gravity lows as well as the land upheaval in Fennoscandia are typically regional phenomena that cannot be seen in a global correlation study as it is blurred by many irrelevant gravity signals. It is suggested that a regional multi-regression analysis with a band-limited spectral gravity signal as the observable, a method tested already 2 decades ago, can absorb possible significant disturbing signals, e.g. from topographic and crustal depth variations, and thereby recover the GIA signal.

  2. A model of the western Laurentide Ice Sheet, using observations of glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Gowan, Evan J.; Tregoning, Paul; Purcell, Anthony; Montillet, Jean-Philippe; McClusky, Simon

    2016-05-01

    We present the results of a new numerical model of the late glacial western Laurentide Ice Sheet, constrained by observations of glacial isostatic adjustment (GIA), including relative sea level indicators, uplift rates from permanent GPS stations, contemporary differential lake level change, and postglacial tilt of glacial lake level indicators. The later two datasets have been underutilized in previous GIA based ice sheet reconstructions. The ice sheet model, called NAICE, is constructed using simple ice physics on the basis of changing margin location and basal shear stress conditions in order to produce ice volumes required to match GIA. The model matches the majority of the observations, while maintaining a relatively realistic ice sheet geometry. Our model has a peak volume at 18,000 yr BP, with a dome located just east of Great Slave Lake with peak thickness of 4000 m, and surface elevation of 3500 m. The modelled ice volume loss between 16,000 and 14,000 yr BP amounts to about 7.5 m of sea level equivalent, which is consistent with the hypothesis that a large portion of Meltwater Pulse 1A was sourced from this part of the ice sheet. The southern part of the ice sheet was thin and had a low elevation profile. This model provides an accurate representation of ice thickness and paleo-topography, and can be used to assess present day uplift and infer past climate.

  3. Glacial Isostatic Adjustment in the Great Lakes Region Inferred by Tide Gauges and Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Shum, C.; Kuo, C.; Mitrovica, J. X.

    2002-05-01

    Glacial isostatic adjustment (GIA) of the solid Earth due to deglaciation since the last Ice Age is characterized by its viscous rebound as a result of relaxation of the shear stresses inside the Earth. GIA uplift (in the form of 3-D crustal motion and the ensuing geoid change due to redistribution of mass in the solid Earth) has been recently measured with long-term GPS (e.g., the BIFROST project). In this paper, we used more than 50 long-term (1860-2000) water level gauges located around the Great Lakes, and satellite altimetry measurements (TOPEX/ POSEIDON and Geosat, 9-15 year data span) to measure the vertical motion of the region. Preliminary results indicate that Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario, are uplifting at a rate of 1.8, 0.9, 1.4, -0.5, and 1.0 mm/yr, respectively. The uncertainty of the measurement is primarily due to the error in satellite altimetry due to its relatively short data span. The results are compared with available GIA models, including ICE-4G, and Mitrovica-Milne 2001 models, as well as relative vertical motion measured using water level gauges [Manville et al., 2001]. Analysis also includes the examination of GIA models using different estimates of mantle thickness and upper and lower mantle viscosity. Results using the vertical measurement in an inverse geophysical solution will be reported.

  4. Geologic and isostatic map of the Nenana Basin area, central Alaska

    USGS Publications Warehouse

    Frost, G.M.; Barnes, D.F.; Stanley, R.G.

    2002-01-01

    Introduction The Nenana Basin area is a prospective petroleum province in central Alaska, and this geologic and isostatic gravity map is part of a petroleum resource assessment of the area. The geology was compiled from published sources (Chapman and others, 1971, 1975a, 1975b, 1982; Chapman and Yeend, 1981; Csejtey and others, 1986; Jones and others, 1983; Pewe and others, 1966; Reed, 1961; and Weber and others, 1992), as shown on the index map (map sheet). Map units are organized and presented according to the scheme of lithotectonic terranes proposed by Jones and others (1987) and Silberling and Jones (1984); we recognize, however, that this terrane scheme is controversial and likely to be revised in the future. In some cases, we combined certain terranes because we were unable to match the terrane boundaries given by Jones and others (1987) and Silberling and Jones (1984) with specific faults shown on existing geologic maps. Postaccretion cover deposits represent overlap assemblages that depositionally overlie accreted terranes. Plutonic igneous rocks shown on this map include several plutons that are clearly postaccretionary, based on isotopic ages and (or) field relations. It is possible that some of the plutons predate accretion, but this has not been demonstrated. According to Jones and others (1982), the terranes in the area of our map were assembled during late Mesozoic or earliest Cenozoic time. The gravity contours are derived from data used in earlier compilations (Barnes, 1961, 1977; Hackett, 1981; Valin and others, 1991; Frost and Stanley, 1991) that are supplemented by some National Oceanic and Atmospheric Administration data along the Alaska Pipeline level line (W.E. Strange, written commun., 1980). The earlier compilations were used for simple Bouguer maps, prepared primarily by non-digital methods, and are superseded by this map. The present map is the result of digital processing that includes the 1967 Geodetic Reference System, the IGSN-71

  5. A Joint Bayesian Inversion for Glacial Isostatic Adjustment in North America and Greenland

    NASA Astrophysics Data System (ADS)

    Davis, J. L.; Wang, L.

    2014-12-01

    We have previously presented joint inversions of geodetic data for glacial isostatic adjustment (GIA) fields that employ a Bayesian framework for the combination of data and models. Data sets used include GNSS, GRACE gravity, and tide-gauge data, in order to estimate three-dimensional crustal deformation, geoid rate, relative sea-level change (RSLC). The benefit to this approach is that solutions are less dependent on any particular Earth/ice model used to calculate the GIA fields, and instead employ a suite of GIA predictions that are then used to calculate statistical constraints. This approach was used both for the determination of the SNARF geodetic reference frame for North America, and for a study of GIA in Fennoscandia (Hill et al., 2010). One challenge to the method we developed is that the inherent reduction in resolution of, and correlation among, GRACE Stokes coefficients caused by the destriping procedure (Swenson and Wahr, 2006; Duan et al., 2009) was not accounted for. This important obstacle has been overcome by developing a Bayesian approach to destriping (Wang et al., in prep.). However, important issues of mixed resolution of these data types still remain. In this presentation, we report on the progress of this effort, and present a new GIA field for North America. For the first time, the region used in the solution includes Greenland, in order to provide internally consistent solutions for GIA, the spatial and temporal variability of present-day sea-level change, and present-day melting in Greenland.

  6. STS-8 onboard crew press conference

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Six news reporters listen to a response from Astronaut Guion S. Bluford (note TV monitor) in a rare space-to-Earth press conference involving all the STS-8 crew. The participants are, left to right, Gary Schwitzer, Cable News Network; Morton Dean, CBS; Roy Neal, NBC; Lynn Sherr, ABC; Howard Benedict, Associated Press; Al Rossiter, United Press International. The astronauts on the monitor are Richard H. Truly, cneter left, crew commander; Daniel C. Brandenstein, lower left, pilot; and Dr. William E. Thornton, upper left, Guion S. Bluford, upper right; and Dale E. Gardner, all mission specialists.

  7. Powder pressing in a macrosonic field

    NASA Technical Reports Server (NTRS)

    Protipopescu, A.; Dragan, O.; Ciovica, D.

    1974-01-01

    An investigation was conducted to extend the technology of powder product manufacturing to new forms and sizes, to improve their quality as well as pressing efficiency and to reduce waste. In the course of metal and nonmetal powder briquette pressing, macrosounds were associated with the external static pressing force, which led to an increase in the relative height, density and physicomechanical characteristics of the briquettes. This method permits the extension of the range of products that can be manufactured from powders and the improvement of their quality.

  8. Course Does a Critical Study of Press in Capitalist Society.

    ERIC Educational Resources Information Center

    Winter, James

    1986-01-01

    Describes a course that documents in often laborious and relatively uncritical detail the history of the Canadian press and its American and British antecedents. Describes a course on the contemporary press consisting of various forms of press criticism. (HTH)

  9. Apollo 13 Facts [Post Flight Press Conference

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Apollo 13 astronauts, James Lovell, Jr., John Swigert, Jr., and Fred Haise, Jr., are seen during this post flight press conference. They describe their mission and answer questions from the audience.

  10. Student Press Law: What Lies Ahead?

    ERIC Educational Resources Information Center

    Eveslage, Thomas

    1980-01-01

    Assesses recent developments in student press rights in the areas of prior restraint, libel and obscenity, and material and substantial disruption, and predicts future trends in student rights litigation. (TJ)

  11. Gas-driven filter pressing in magmas

    USGS Publications Warehouse

    Sisson, T.W.; Bacon, C.R.

    1999-01-01

    Most silicic and some mafic magmas expand via second boiling if they crystallize at depths of about 10 km or less. The buildup of gas pressure due to second boiling can be relieved by expulsion of melt out of the region of crystallization, and this process of gas-driven filter pressing assists the crystallization differentiation of magmas. For gas-driven filter pressing to be effective, the region of crystallization must inflate slowly relative to buildup of pressure and expulsion of melt These conditions are satisfied in undercooled magmatic inclusions and in thin sheets of primitive magma underplating cooler magma reservoirs. Gas-driven filter pressing thereby adds fractionated melt to magma bodies. Gas-driven filter pressing is probably the dominant process by which highly evolved melts segregate from crystal mush to form aplitic dikes in granitic plutons; this process could also account for the production of voluminous, crystal-poor rhyolites.

  12. Thermal Conductances of Pressed Copper Contacts

    NASA Technical Reports Server (NTRS)

    Salerno, L.; Kittel, P.; Spivak, A.

    1986-01-01

    Report describes investigation of thermal conductivities of smooth copper contacts pressed together at liquid-helium temperatures. Investigation prompted by need for accurate thermal models for infrared detectors and other cryogenic instruments.

  13. World Gravity Map: a set of global complete spherical Bouguer and isostatic anomaly maps and grids

    NASA Astrophysics Data System (ADS)

    Bonvalot, S.; Balmino, G.; Briais, A.; Kuhn, M.; Peyrefitte, A.; Vales, N.; Biancale, R.; Gabalda, G.; Reinquin, F.

    2012-04-01

    We present here a set of digital maps of the Earth's gravity anomalies (surface free air, Bouguer and isostatic), computed at Bureau Gravimetric International (BGI) as a contribution to the Global Geodetic Observing Systems (GGOS) and to the global geophysical maps published by the Commission for the Geological Map of the World (CGMW) with support of UNESCO and other institutions. The Bouguer anomaly concept is extensively used in geophysical interpretation to investigate the density distributions in the Earth's interior. Complete Bouguer anomalies (including terrain effects) are usually computed at regional scales by integrating the gravity attraction of topography elements over and beyond a given area (under planar or spherical approximations). Here, we developed and applied a worldwide spherical approach aimed to provide a set of homogeneous and high resolution gravity anomaly maps and grids computed at the Earth's surface, taking into account a realistic Earth model and reconciling geophysical and geodetic definitions of gravity anomalies. This first version (1.0) has been computed by spherical harmonics analysis / synthesis of the Earth's topography-bathymetry up to degree 10800. The detailed theory of the spherical harmonics approach is given in Balmino et al., (Journal of Geodesy, 2011). The Bouguer and terrain corrections have thus been computed in spherical geometry at 1'x1' resolution using the ETOPO1 topography/bathymetry, ice surface and bedrock models from the NOAA (National Oceanic and Atmospheric Administration) and taking into account precise characteristics (boundaries and densities) of major lakes, inner seas, polar caps and of land areas below sea level. Isostatic corrections have been computed according to the Airy-Heiskanen model in spherical geometry for a constant depth of compensation of 30km. The gravity information given here is provided by the Earth Geopotential Model (EGM2008), developed at degree 2160 by the National Geospatial

  14. Isostatic gravity map of the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    Ponce, D.A.; Blakely, R.J.; Morin, R.L.; Mankinen, E.A.

    2002-03-12

    Gravity investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W. An isostatic gravity map of the Death Valley ground-water model was prepared from over 40,000 gravity stations, most of which are publicly available on a CD-ROM of gravity data of Nevada (Ponce, 1997). The map also includes gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1998; Morin and Blakely, 1999). A subset of these gravity data in the Nevada Test Site and vicinity were described in detail by Harris and others (1989) who included information on gravity meters used, dates of collection, sources, descriptions of base stations, plots of data, and digital and paper lists of principal facts. For display purposes only, gravity data within Yucca Flat were thinned by a factor of 10. The digital gravity data set was gridded at an interval of 400 m using a computer program (Webring, 1981) based on a minimum curvature algorithm by Briggs (1974). The resulting grid was then interpolated to a 200-m grid to minimize pixel size, and then it was color contoured.

  15. A new glacial isostatic adjustment model of the Innuitian Ice Sheet, Arctic Canada

    NASA Astrophysics Data System (ADS)

    Simon, K. M.; James, T. S.; Dyke, A. S.

    2015-07-01

    A reconstruction of the Innuitian Ice Sheet (IIS) is developed that incorporates first-order constraints on its spatial extent and history as suggested by regional glacial geology studies. Glacial isostatic adjustment modelling of this ice sheet provides relative sea-level predictions that are in good agreement with measurements of post-glacial sea-level change at 18 locations. The results indicate peak thicknesses of the Innuitian Ice Sheet of approximately 1600 m, up to 400 m thicker than the minimum peak thicknesses estimated from glacial geology studies, but between approximately 1000 to 1500 m thinner than the peak thicknesses present in previous GIA models. The thickness history of the best-fit Innuitian Ice Sheet model developed here, termed SJD15, differs from the ICE-5G reconstruction and provides an improved fit to sea-level measurements from the lowland sector of the ice sheet. Both models provide a similar fit to relative sea-level measurements from the alpine sector. The vertical crustal motion predictions of the best-fit IIS model are in general agreement with limited GPS observations, after correction for a significant elastic crustal response to present-day ice mass change. The new model provides approximately 2.7 m equivalent contribution to global sea-level rise, an increase of +0.6 m compared to the Innuitian portion of ICE-5G. SJD15 is qualitatively more similar to the recent ICE-6G ice sheet reconstruction, which appears to also include more spatially extensive ice cover in the Innuitian region than ICE-5G.

  16. An assessment of the ICE6G_C(VM5a) glacial isostatic adjustment model

    NASA Astrophysics Data System (ADS)

    Purcell, A.; Tregoning, P.; Dehecq, A.

    2016-05-01

    The recent release of the next-generation global ice history model, ICE6G_C(VM5a), is likely to be of interest to a wide range of disciplines including oceanography (sea level studies), space gravity (mass balance studies), glaciology, and, of course, geodynamics (Earth rheology studies). In this paper we make an assessment of some aspects of the ICE6G_C(VM5a) model and show that the published present-day radial uplift rates are too high along the eastern side of the Antarctic Peninsula (by ˜8.6 mm/yr) and beneath the Ross Ice Shelf (by ˜5 mm/yr). Furthermore, the published spherical harmonic coefficients—which are meant to represent the dimensionless present-day changes due to glacial isostatic adjustment (GIA)—contain excessive power for degree ≥90, do not agree with physical expectations and do not represent accurately the ICE6G_C(VM5a) model. We show that the excessive power in the high-degree terms produces erroneous uplift rates when the empirical relationship of Purcell et al. (2011) is applied, but when correct Stokes coefficients are used, the empirical relationship produces excellent agreement with the fully rigorous computation of the radial velocity field, subject to the caveats first noted by Purcell et al. (2011). Using the Australian National University (ANU) groups CALSEA software package, we recompute the present-day GIA signal for the ice thickness history and Earth rheology used by Peltier et al. (2015) and provide dimensionless Stokes coefficients that can be used to correct satellite altimetry observations for GIA over oceans and by the space gravity community to separate GIA and present-day mass balance change signals. We denote the new data sets as ICE6G_ANU.

  17. Vacuum isostatic micro molding of microfluidic structures into polytetrafluoroethylene (PTFE) materials

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd E.

    2008-04-01

    Polytetrafluoroethylene (PTFE) is an ideal material for use in microfluidic applications, such as industrial inkjet and biomedical analysis devices. PTFE has outstanding physical properties; such as chemical inertness and resistance to chemical corrosion, even when exposed to a strong acid, alkali and oxidants. Its properties provide for superior electrical insulation and thermal stability, which is not affected by wide ranges in temperature and frequency. Its non-absorption of moisture makes it a perfect material for consideration in micro-fluidic devices used in chemical analysis, fluidic photonic sensors and biomedical diagnostics. This paper presents an overview of a unique fabrication method that incorporates a variety of elements to establish a processing technique that can form micro channels, complex filter arrays and reflective micro mirror structures into PTFE materials for such applications. Using a modified isostatic compression molding process, this new technique incorporates the addition of a vacuum to assist in the reliable molding of micron structures and further densification of the fused or semi-fused PTFE. Various micro-structured electroformed and micro-machined shims are demonstrated to form small microstructures into the surface of the PTFE material. The combination of the vacuum and the electroformed shim within the molding process noticeably increases the precision, reproducibility and resolution of microstructures that can be realized. The paper will describe the molding hardware involved, process parameters and the resulting microfluidic channels and complex filter and capillary structures formed. Function testing and metrology of the micro-structure geometry formed on each sample will be compared to the original design mandrel geometry.

  18. Ice loading model for Glacial Isostatic Adjustment in the Barents Sea constrained by GRACE gravity observations

    NASA Astrophysics Data System (ADS)

    Root, Bart; Tarasov, Lev; van der Wal, Wouter

    2014-05-01

    The global ice budget is still under discussion because the observed 120-130 m eustatic sea level equivalent since the Last Glacial Maximum (LGM) can not be explained by the current knowledge of land-ice melt after the LGM. One possible location for the missing ice is the Barents Sea Region, which was completely covered with ice during the LGM. This is deduced from relative sea level observations on Svalbard, Novaya Zemlya and the North coast of Scandinavia. However, there are no observations in the middle of the Barents Sea that capture the post-glacial uplift. With increased precision and longer time series of monthly gravity observations of the GRACE satellite mission it is possible to constrain Glacial Isostatic Adjustment in the center of the Barents Sea. This study investigates the extra constraint provided by GRACE data for modeling the past ice geometry in the Barents Sea. We use CSR release 5 data from February 2003 to July 2013. The GRACE data is corrected for the past 10 years of secular decline of glacier ice on Svalbard, Novaya Zemlya and Frans Joseph Land. With numerical GIA models for a radially symmetric Earth, we model the expected gravity changes and compare these with the GRACE observations after smoothing with a 250 km Gaussian filter. The comparisons show that for the viscosity profile VM5a, ICE-5G has too strong a gravity signal compared to GRACE. The regional calibrated ice sheet model (GLAC) of Tarasov appears to fit the amplitude of the GRACE signal. However, the GRACE data are very sensitive to the ice-melt correction, especially for Novaya Zemlya. Furthermore, the ice mass should be more concentrated to the middle of the Barents Sea. Alternative viscosity models confirm these conclusions.

  19. Correcting for Glacial Isostatic Adjustment in the static gravity field in northwestern Europe

    NASA Astrophysics Data System (ADS)

    Root, Bart; van der Wal, Wouter; Ebbing, Jörg; Novák, Pavel; Vermeersen, Bert

    2014-05-01

    Around 20,000 years ago, large ice sheets covered the surface of the Earth. In the late-Pleistocene large parts of these ice sheets melted, causing the crustal surface of Earth to relax. This process is called Glacial Isostatic Adjustment (GIA) and can be observed by sea level indicators, GPS uplift rates, and gravity changes. Several studies have tried to observe GIA in the static gravity field; however, they used simplistic models for the lithosphere. This study has two aims: i) to find out if it is possible to retrieve the GIA gravity signal with current knowledge of the density distribution of the lithosphere and ii) to see what the effect is on geophysical models that are constrained by gravity after correcting for the GIA gravity signal. To remove lithospheric density anomalies from the static gravity field, a spherical harmonic forward gravity field model is used, which calculates the gravity signal of a layered Earth. We found that is not possible to separate the GIA gravity effect from the uncertain density anomalies and boundary geometries in the crust and upper mantle. Therefore, we propose to correct the static gravity field with results from a numerical GIA model. Unknown upper mantle and lower mantle viscosities in such a model are estimated using local GIA observations, and using the global ice loading model history, ICE-5G. The best fitting models produce a free-air gravity anomaly of -28.4 +/-1.5 mGal (peak) and a remaining uplift of 240 m. When gravity observations and topography are corrected for GIA in geophysical modeling, this results in significant changes in the geometry or density of lithospheric structures, up to 30 km for a lithospheric model in Fennoscandia. The correction will also have an impact on the understanding of density anomalies of the lithosphere in other areas where GIA gravity anomalies are significant, such as North America, Greenland, and Antarctica.

  20. Densification and permeability reduction in hot-pressed calcite: A kinetic model

    NASA Astrophysics Data System (ADS)

    Zhu, Wenlu; Evans, Brian; Bernabé, Yves

    1999-11-01

    Laboratory studies on hot isostatically pressed (HIP) calcite reveal that the evolution of porosity and permeability during mechanical compaction can be divided into two distinct regimes. At high porosities, permeability is related approximately to porosity raised to the third power. However, below a porosity called the crossover porosity, the power law relationship no longer applies, and permeability reduction is accelerated. At a porosity of ˜4%, permeability becomes too low to be measured, indicating that a percolation threshold has been reached. In previous studies the time evolutions of porosity and permeability were not predicted, and further, the crossover porosity was introduced as an empirical input parameter. In this study we developed a unified model combining crack healing with densification by power law creep to reproduce porosity evolution as a function of time. Both the healing and the creep are deterministically controlled by the pressure and temperature. Permeability can then be calculated by incorporating quantitative microstructural data (i.e., pore size distribution) into a three-dimensional cubic network model. We were able to reproduce the permeability-porosity relationship in hot-pressed calcite aggregates in both high- and low-porosity regimes. In particular, our model predicted a crossover porosity of ˜7% and a percolation threshold of ˜4%, both in a good agreement with the experimental data. However, we generally overestimated the absolute values of permeability. Because the model yielded correct absolute permeability values in the case when the pore size distribution was known, we suppose that at least part of the error arises from inadequate data for microstructure.

  1. A new Approach to Combine GRACE and ICESat Observations to Estimate Glacial Isostatic Adjustment in East Antarctic

    NASA Astrophysics Data System (ADS)

    Kallenberg, B.; Tregoning, P.; Purcell, A. P.

    2014-12-01

    Monitoring and understanding ongoing changes in Antarctic mass balance is of great interest, as the melting of the ice sheet would significantly contribute to global sea level changes. While scientists agree that the West Antarctic ice sheet is losing mass, opinions about the East Antarctic ice sheet are more widespread, with some areas showing an increase in mass. In recent years satellite missions have significantly contributed to the understanding of ongoing changes within the polar ice sheets, and became an important tool in detecting variations in ice height, ice mass and bedrock isostasy. The Gravity Recovery And Climate Experiment (GRACE) mission detects mass loss in regions where the ice sheet has its bed well below sea level and where warmer ocean water penetrates beneath the ice sheet, melting it from the base. Meanwhile an increase in mass has been observed in regions along the East Antarctic coastline, raising the question whether GRACE detects glacial isostatic adjustment due to ice mass loss or an actual increase in snowfall, contributing positively to surface mass balance. To improve our understanding on the contribution of glacial isostatic adjustment and surface mass balance to mass variations, we developed a new approach on how to subtract elevation changes observed by satellite altimetry from observed mass changes as detected by GRACE. We have established our own firn compaction model that we apply to the altimetry data to subtract changes due to the densification of snow, before using the ICESat observations. We will present results of the firn compaction model and our approach on combining GRACE and ICESat observations to separate the contribution of glacial isostatic adjustment from ongoing surface mass changes in East Antarctica.

  2. Graphic Arts: Book Three. The Press and Related Processes.

    ERIC Educational Resources Information Center

    Farajollahi, Karim; And Others

    The third of a three-volume set of instructional materials for a graphic arts course, this manual consists of nine instructional units dealing with presses and related processes. Covered in the units are basic press fundamentals, offset press systems, offset press operating procedures, offset inks and dampening chemistry, preventive maintenance…

  3. Along Freedom's Double Edge: The Arab Press Under Israeli Occupation.

    ERIC Educational Resources Information Center

    Nasser, Munir K.

    This paper examines the Arab press under Israeli occupation and presents two hypotheses: freedom of the press under occupation serves both Israeli interests and the Arab population, and freedom of the Arab press under occupation is "relative" and "controlled." By allowing freedom of expression, the Israelis achieve several aims: a free press will…

  4. Textbook Sales Drop, and University Presses Search for Reasons

    ERIC Educational Resources Information Center

    Howard, Jennifer

    2008-01-01

    This article reports that textbook sales are falling at many university presses, a trend that has accelerated in the past couple of months. That's the word from press directors anxious about the decline but unsure what's causing it or how to stop it. Not every press has been affected. Two of the biggest players, Oxford University Press and…

  5. Geodetic Observations of Glacial Isostatic Adjustment in Southeast Alaska and its Implication of Earth Rheology

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Freymueller, J. T.

    2012-12-01

    Benefiting from a denser network and more Global Positioning System (GPS) data, we derived velocities of the GPS stations in southeast Alaska with higher time resolution and accuracy than previously published data. GPS stations have recorded rapid uplift rates of up to 34 mm/yr over the last two decades, although uplift rates have varied with time over that period. We have refined previous geodynamic models of glacial isostatic adjustment in southeast Alaska and hope to improve our understanding of Earth rheology, using recently published digital elevation model analyses of recent glacier thickness changes. Thickness changes of Alaska, Yukon and British Columbia glaciers are based on Berthier et al. (2010). We ironed out the blank areas of their published data and constructed a 10-km gridded mass change model. Displacements were calculated by approximating the spatial load changes using 10-km diameter discs. Load model histories follow the Little Ice Age (LIA) load history compiled by Larsen et al. (2005). In our Earth model, the variable parameters include lithospheric elastic thickness, 30 - 120 km, and asthenosphere viscosity 10^18 - 2.5 x 10^19 Pa s. The same fixed parameters as in previous models include the asthenosphere thickness of 110 km and upper mantle viscosity 4 x 10^20 Pa s. In our best-fit model, the lithospheric elastic thickness is estimated to be 50 km, ~20% smaller than previous models. The asthenosphere viscosity is determined to be ~1.5 x 10^19 Pa s, ~3 times larger than previous estimates. Berthier, E., E. Schiefer, G. K. C. Clarke, B. Menounos, and F. Rémy (2010), Contribution of Alaskan glaciers to sea-level rise derived from satellite imagery, Nat. Geosci., 3, 92-95, doi:10.1038/ngeo737. Larsen, C. F., R. J. Motyka, J. T. Freymueller, K. A. Echelmeyer, and E. R. Ivins (2005), Rapid viscoelastic uplift in southeast Alaska caused by post-Little Ice Age glacial retreat, Earth Planet. Sci. Lett., 237, 548-560, doi:10.1016/j.epsl.2005.06.032.

  6. Use of GRACE determined secular gravity rates for glacial isostatic adjustment studies in North-America

    NASA Astrophysics Data System (ADS)

    van der Wal, Wouter; Wu, Patrick; Sideris, Michael G.; Shum, C. K.

    2008-10-01

    Monthly geopotential spherical harmonic coefficients from the GRACE satellite mission are used to determine their usefulness and limitations for studying glacial isostatic adjustment (GIA) in North-America. Secular gravity rates are estimated by unweighted least-squares estimation using release 4 coefficients from August 2002 to August 2007 provided by the Center for Space Research (CSR), University of Texas. Smoothing is required to suppress short wavelength noise, in addition to filtering to diminish geographically correlated errors, as shown in previous studies. Optimal cut-off degrees and orders are determined for the destriping filter to maximize the signal to noise ratio. The halfwidth of the Gaussian filter is shown to significantly affect the sensitivity of the GRACE data (with respect to upper mantle viscosity and ice loading history). Therefore, the halfwidth should be selected based on the desired sensitivity. It is shown that increase in water storage in an area south west of Hudson Bay, from the summer of 2003 to the summer of 2006, contributes up to half of the maximum estimated gravity rate. Hydrology models differ in the predictions of the secular change in water storage, therefore even 4-year trend estimates are influenced by the uncertainty in water storage changes. Land ice melting in Greenland and Alaska has a non-negligible contribution, up to one-fourth of the maximum gravity rate. The estimated secular gravity rate shows two distinct peaks that can possibly be due to two domes in the former Pleistocene ice cover: west and south east of Hudson Bay. With a limited number of models, a better fit is obtained with models that use the ICE-3G model compared to the ICE-5G model. However, the uncertainty in interannual variations in hydrology models is too large to constrain the ice loading history with the current data span. For future work in which GRACE will be used to constrain ice loading history and the Earth's radial viscosity profile, it is

  7. Glacial isostatic adjustment in Fennoscandia from GRACE data and comparison with geodynamical models

    NASA Astrophysics Data System (ADS)

    Steffen, Holger; Denker, Heiner; Müller, Jürgen

    2008-10-01

    The Earth's gravity field observed by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. Several institutions, such as the GeoForschungsZentrum (GFZ) Potsdam, the University of Texas at Austin, Center for Space Research (CSR) and the Jet Propulsion Laboratory (JPL), Pasadena, provide GRACE monthly solutions, which differ slightly due to the application of different reduction models and centre-specific processing schemes. The GRACE data are used to investigate the mass variations in Fennoscandia, an area which is strongly influenced by glacial isostatic adjustment (GIA). Hence the focus is set on the computation of secular trends. Different filters (e.g. isotropic and non-isotropic filters) are discussed for the removal of high frequency noise to permit the extraction of the GIA signal. The resulting GRACE based mass variations are compared to global hydrology models (WGHM, LaDWorld) in order to (a) separate possible hydrological signals and (b) validate the hydrology models with regard to long period and secular components. In addition, a pattern matching algorithm is applied to localise the uplift centre, and finally the GRACE signal is compared with the results from a geodynamical modelling. The GRACE data clearly show temporal gravity variations in Fennoscandia. The secular variations are in good agreement with former studies and other independent data. The uplift centre is located over the Bothnian Bay, and the whole uplift area comprises the Scandinavian Peninsula and Finland. The secular variations derived from the GFZ, CSR and JPL monthly solutions differ up to 20%, which is not statistically significant, and the largest signal of about 1.2 μGal/year is obtained from the GFZ solution. Besides the GIA signal, two peaks with positive trend values of about 0.8 μGal/year exist in central eastern Europe, which are not GIA-induced, and

  8. Inverting Glacial Isostatic Adjustment with Paleo Sea Level Records using Bayesian Framework and Burgers Rheology

    NASA Astrophysics Data System (ADS)

    Caron, L.; Metivier, L.; Greff-Lefftz, M.; Fleitout, L.; Rouby, H.

    2015-12-01

    Glacial Isostatic Adjustment models most often assume a mantle with a viscoelastic Maxwell rheology and a given ice history model. Here we use a Bayesian Monte Carlo with Markov Chains formalism to invert the global GIA signal simultaneously for the mechanical properties of the mantle and for the volume of the various ice-sheets using as starting ice models two distinct previously published ice histories. Burgers as well as Maxwell rheologies are considered.The fitted data consist of 5720 paleo sea level records from the last 35kyrs, with a world-wide distribution. Our ambition is to present not only the best fitting model, but also the range of possible solutions (within the explored space of parameters) with their respective probability of explaining the data, and thus reveal the trade-off effects and range of uncertainty affecting the parameters. Our a posteriori probality maps exhibit in all cases two distinct peaks: both are characterized by an upper mantle viscosity around 5.1020Pa.s but one of the peaks features a lower mantle viscosity around 3.1021Pa.s while the other indicates lower mantle viscosity of more than 1.1022Pa.s. The global maximum depends upon the starting ice history and the chosen rheology: the first peak (P1) has the highest probability only in the case with a Maxwell rheology and ice history based on ICE-5G, while the second peak (P2) is favored when using ANU-based ice history or Burgers rheology, and is our preferred solution as it is also consistent with long-term geodynamics and gravity gradients anomalies over Laurentide. P2 is associated with larger volumes for the Laurentian and Fennoscandian ice-sheets and as a consequence of total ice volume balance, smaller volumes for the Antactic ice-sheet. This last point interfers with the estimate of present-day ice-melting in Antarctica from GRACE data. Finally, we find that P2 with Burgers rheology favors the existence of a tectosphere, i.e. a viscous sublithospheric layer.

  9. Glacial isostatic adjustment on 3-D Earth models: a finite-volume formulation

    NASA Astrophysics Data System (ADS)

    Latychev, Konstantin; Mitrovica, Jerry X.; Tromp, Jeroen; Tamisiea, Mark E.; Komatitsch, Dimitri; Christara, Christina C.

    2005-05-01

    We describe and present results from a finite-volume (FV) parallel computer code for forward modelling the Maxwell viscoelastic response of a 3-D, self-gravitating, elastically compressible Earth to an arbitrary surface load. We implement a conservative, control volume discretization of the governing equations using a tetrahedral grid in Cartesian geometry and a low-order, linear interpolation. The basic starting grid honours all major radial discontinuities in the Preliminary Reference Earth Model (PREM), and the models are permitted arbitrary spatial variations in viscosity and elastic parameters. These variations may be either continuous or discontinuous at a set of grid nodes forming a 3-D surface within the (regional or global) modelling domain. In the second part of the paper, we adopt the FV methodology and a spherically symmetric Earth model to generate a suite of predictions sampling a broad class of glacial isostatic adjustment (GIA) data types (3-D crustal motions, long-wavelength gravity anomalies). These calculations, based on either a simple disc load history or a global Late Pleistocene ice load reconstruction (ICE-3G), are benchmarked against predictions generated using the traditional normal-mode approach to GIA. The detailed comparison provides a guide for future analyses (e.g. what grid resolution is required to obtain a specific accuracy?) and it indicates that discrepancies in predictions of 3-D crustal velocities less than 0.1 mm yr-1 are generally obtainable for global grids with ~3 × 106 nodes; however, grids of higher resolution are required to predict large-amplitude (>1 cm yr-1) radial velocities in zones of peak post-glacial uplift (e.g. James bay) to the same level of absolute accuracy. We conclude the paper with a first application of the new formulation to a 3-D problem. Specifically, we consider the impact of mantle viscosity heterogeneity on predictions of present-day 3-D crustal motions in North America. In these tests, the

  10. An assessment of the ICE6G_C (VM5A) glacial isostatic adjustment model

    NASA Astrophysics Data System (ADS)

    Purcell, Anthony; Tregoning, Paul; Dehecq, Amaury

    2016-04-01

    The recent release of the next-generation global ice history model, ICE6G_C(VM5a) [Peltier et al., 2015, Argus et al. 2014] is likely to be of interest to a wide range of disciplines including oceanography (sea level studies), space gravity (mass balance studies), glaciology and, of course, geodynamics (Earth rheology studies). In this presentation I will assess some aspects of the ICE6G_C(VM5a) model and the accompanying published data sets. I will demonstrate that the published present-day radial uplift rates are too high along the eastern side of the Antarctic Peninsula (by ˜8.6 mm/yr) and beneath the Ross Ice Shelf (by ˜5 mm/yr). Further, the published spherical harmonic coefficients - which are meant to represent the dimensionless present-day changes due to glacial isostatic adjustment (GIA) - will be shown to contain excessive power for degree ≥ 90, to be physically implausible and to not represent accurately the ICE6G_C(VM5a) model. The excessive power in the high degree terms produces erroneous uplift rates when the empirical relationship of Purcell et al. [2011] is applied but, when correct Stokes' coefficients are used, the empirical relationship will be shown to produce excellent agreement with the fully rigorous computation of the radial velocity field, subject to the caveats first noted by Purcell et al. [2011]. Finally, a global radial velocity field for the present-day GIA signal, and corresponding Stoke's coefficients will be presented for the ICE6GC ice model history using the VM5a rheology model. These results have been obtained using the ANU group's CALSEA software package and can be used to correct satellite altimetry observations for GIA over oceans and by the space gravity community to separate GIA and present-day mass balance change signals without any of the shortcomings of the previously published data-sets. We denote the new data sets ICE6G_ANU.

  11. Sediment basin modeling through GOCE gradients controlled by thermo-isostatic constraints

    NASA Astrophysics Data System (ADS)

    Pivetta, Tommaso; Braitenberg, Carla

    2015-04-01

    Exploration of geodynamic and tectonic structures through gravity methods has experienced an increased interest in the recent years thank's to the possibilities offered by satellite gravimetry (e.g. GOCE). The main problem with potential field methods is the non-uniqueness of the underground density distributions that satisfy the observed gravity field. In terrestrial areas with scarce geological and geophysical information, valid constraints to the density model could be obtained from the application of geodynamic models. In this contribution we present the study of the gravity signals associated to the thermo-isostatic McKenzie-model (McKenzie, 1978) that predicts the development of sedimentary basins from the stretching of lithosphere. This model seems to be particularly intriguing for gravity studies as we could obtain estimates of densities and thicknesses of crust and mantle before and after a rifting event and gain important information about the time evolution of the sedimentary basin. The McKenzie-model distinguishes the rifting process into two distinct phases: a syn-rift phase that occurs instantly and is responsible of the basin formation, the thinning of lithosphere and the upwelling of hot asthenosphere. Then a second phase (post-rift), that is time dependent, and predicts further subsidence caused by the cooling of mantle and asthenosphere and subsequently increase in rock density. From the application of the McKenzie-model we have derived density underground distributions for two scenarios: the first scenario involves the lithosphere density distribution immediately after the stretching event; the second refers to the density model when thermal equilibrium between stretched and unstretched lithospheres is achieved. Calculations of gravity anomalies and gravity gradient anomalies are performed at 5km height and at the GOCE mean orbit quota (250km). We have found different gravity signals for syn-rift (gravimetric maximum) and post-rift (gravimetric

  12. Quantifying subsidence and isostatic readjustment using sedimentary paleomarkers, example from the Gulf of Lion

    NASA Astrophysics Data System (ADS)

    Rabineau, M.; Leroux, E.; Aslanian, D.; Bache, F.; Gorini, C.; Moulin, M.; Molliex, S.; Droz, L.; dos Reis, A. T.; Rubino, J. L.; Guillocheau, F.; Olivet, J. L.

    2014-02-01

    Passive margins are characterised by an important tectonic and thermal subsidence, which favours a good preservation of sedimentary sequences. This sedimentation in turn enhances the subsidence because of loading effects. We present here a direct method based on sedimentary markers seen on seismic data, to evaluate total subsidence rates from the coast to the outer shelf and to the deep basin in the Gulf of Lion, from the beginning of massive salt deposition up to present day (the last circa 6 Ma) with minimal theoretical assumptions. On the shelf, the Pliocene-Quaternary subsidence shows a seaward tilt reaching a rate of 240 m/Ma (±15 m/Ma) at the shelf break (70 km from the present day coastline) (i.e. a total angle of rotation of 0.88° (0.16°/Ma)). We were also able to measure and quantify for the first time the isostatic rebound of the outer shelf due to the Messinian salinity crisis (MSC). This value is very high and reaches up to 1.3 km of uplift during the crisis around the Herault-Sète canyon heads (around 1.8 km/Ma). On the slope, we also find a seaward tilting subsidence from Km 90 to Km 180 with a measured angle of 1.41°. From 180 km to the deepest part of the basin, the total subsidence is then almost vertical and reaches 960 m/Ma (±40 m/Ma) during the last 5.7 Ma (±0.25 Ma) in the deepest part of the basin. The subsidence is organised in three compartments that seem related to the very deep structure of the margin during the opening of the Liguro-provencal basin. These very high total subsidence rates enable high sedimentation rates along the margin with sediments provided by the Rhône river flowing from the Alps, which in turn enable the detailed record of climate evolution during Pliocene-Quaternary that make of the Gulf of Lion a unique archive.

  13. Roller presses -- Versatile equipment for mineral processing

    SciTech Connect

    Pietsch, W.

    1995-12-31

    Roller presses were first invented in the middle of the 19th century for the economical size enlargement of coal fines as fuels. In addition to contemporary coal briquetting, in fields such as smokeless fuel and form-coke, it was found that redesigned and modernized roller presses, which are now capable of exerting high forces, are versatile machines for many tasks in mineral processing. Today they are used for: the classic pressure agglomeration and the new high pressure comminution. In pressure agglomeration, the characteristics of fine minerals are improved by forming briquettes or granulated products from compacts. During size enlargement with roller presses briquettes are directly obtained while granular materials are produced by crushing and sizing of compacted sheets. A relatively new application of roller presses in mineral processing is the utilization of the crushing effect when brittle materials pass the nip area between the rollers. It was found that this crushing mechanism is very efficient thus saving energy, particularly in grinding circuits handling large capacities. The paper introduces the fundamentals of the process and describes the design as well as applications of modern roller presses in mineral processing.

  14. Lever-press conditioning in the crab.

    PubMed

    Abramson, C I; Feinman, R D

    1990-08-01

    An operant chamber has been developed for studying lever-press conditioning in the green crab Carcinus maenas. In one series of experiments, animals were presented with a single bar and were reinforced with food for every bar press. Performance increased over time and high rates of responding were observed after 2 days of training. The response rate was always higher than that for a yoked (noncontingent) control group. When the contingencies were switched, the animals adjusted to the new conditions. Discrimination in the lever-press apparatus was demonstrated in a second experiment in which crabs had to choose between two bars, one (S+) caused food to be dispensed while the other (S-) was inactive. Experimental animals pressed the S+ bar at a significantly higher rate than the S- bar. When the contingencies associated with the lever were reversed, animals learned to switch to the correct bar by the second day. It was not necessary to reinforce every response: animals maintained high rates of responding on a schedule where every other response was reinforced. Animals used different methods of pressing the bar; the most common was extension of the claw, predominantly at the meropodite-carpopodite joint. PMID:2255730

  15. AUPress: A Comparison of an Open Access University Press with Traditional Presses

    ERIC Educational Resources Information Center

    McGreal, Rory; Chen, Nian-Shing

    2011-01-01

    This study is a comparison of AUPress with three other traditional (non-open access) Canadian university presses. The analysis is based on the rankings that are correlated with book sales on Amazon.com and Amazon.ca. Statistical methods include the sampling of the sales ranking of randomly selected books from each press. The results of one-way…

  16. A precision press-fit instrument for assembling small parts

    NASA Astrophysics Data System (ADS)

    Lou, Zhifeng; Wang, Xiaodong; You, Bo; Xu, Yang

    2015-02-01

    In the paper, a precision press-fit instrument for assembling small interference fitting parts is introduced, which includes pressing module and parts alignment module. The pressing module was used to clamp and position parts, and parts alignment module was used for the two parts' alignment. Through analyzing press-fit control method, component alignment and adjustment strategy, and machine vision device calibration method, the instrument meets the pressing requirements of precision small components. Finite element method is used to predict the reasonable range of press-fit force, and pressing result of the instrument is tested by experiments.

  17. Improvement of touch sensitivity by pressing.

    PubMed

    Jeong, Hie-yong; Higashimori, Mitsuru; Kaneko, Makoto

    2008-01-01

    It is really interesting to know how a blood flow has an influence on a touch sensitivity during human fingertip exploration over an environment. In this paper, we examine experimentally how the touch sensitivity is changed under the condition that the blood flow is interrupted compulsorily by pressing the proximal phalange of human finger. Through the weight discrimination test based on Weber's Law, we found that the touch sensitivity improves temporarily with the statistical significance test of below 0.1 %, when a finger proximal phalange is bound and pressed. Experimental results also show that there exists a meaningful correlationship between the stiffness of fingertip and the touch sensitivity. PMID:19163188

  18. STS-121: Discovery Post Launch Press Briefing

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The briefing begins with Dean Acousta (NASA Press Secretary) introducing Michael Griffin (NASA Administrator), Bill Gerstenmaier (Associate Administrator for Space Operations) Wayne Hale (Space Shuttle Program Manager), John Shannon (Chairman, Mission Management Team, JSC), and Mike Leinbach (NASA Launch Director). The teams effort and dedication paid off in the form of a perfect launch and the weather cooperated. The Mission Management Team no problems during inspection. Debris assessment at 2 min. 47 sec. and 4 min. 50 sec. will be discussed when that information becomes available.The floor was then open for questions from the press.

  19. Aerial view of the Press Site

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this aerial view, The News Center sits beyond a large parking lot, on a hill at the northeastern end of the Launch Complex 39 Area , next to the turn basin (at left). From left, the grandstand faces the launch pads several miles away on the Atlantic seashore; behind it, the television studio is the site of media conferences; next, the large white-roofed building is the hub of information and activity for press representatives. Lined up on the right of the Press Site are various buildings and trailers, home to major news networks. The parking lot can accommodate the hundreds of media personnel who attend Space Shuttle launches.

  20. Lithospheric thickness jumps at the S-Atlantic continental margins from satellite gravity data and modelled isostatic anomalies

    NASA Astrophysics Data System (ADS)

    Shahraki, Meysam; Schmeling, Harro; Haas, Peter

    2016-04-01

    Isostatic equilibrium is a good approximation for passive continental margins. In these regions, geoid anomalies are proportional to the local dipole moment of density-depth distributions, which can be used to constrain the thickness of lithospheric jumps and corresponding tectonic stress. We analysed satellite derived geoid data and, after filtering, extracted typical averaged profiles across the Western and Eastern passive margins of the South Atlantic. They show geoid jumps of 8.1 m and 7.0 m for the Argentinian and African sides, respectively. Together with topography data and reasonable assumptions about densities these jumps are interpreted as isostatic geoid anomalies and yield best-fitting crustal and lithospheric thicknesses. They reveal a small asymmetry between the African and S-American crusts and lithospheres by a few kilometers. On both sides, the continental lithosphere is about 15 - 30km thicker than the oceanic lithosphere. To keep such geoid jumps stable over O(100Ma) fully dynamic models show that lithospheric viscosities must be of the order of 1e23 Pa s.

  1. Glacial Isostatic Adjustment as a key to understand the neotectonics of northern Central Europe

    NASA Astrophysics Data System (ADS)

    Brandes, Christian; Steffen, Holger; Wu, Patrick

    2014-05-01

    Northern Central Europe is generally regarded as aseismic, however, several historic earthquakes with intensities of up to VII occurred in this region during the last 1200 years (Leydecker, 2009). In a pilot study we analysed the Osning Thrust, which is a one of the major Mesozoic fault zones in northern Central Europe. Several soft-sediment deformation structures like fault-arrays and a sand volcano developed in aeolian sediments, were caused by earthquakes along the Osning Thrust. The growth-strata of faults was dated with the OSL method and showed that the deformation took place between 15.9 ± 1.6 to 13.1 ± 1.5 ka (Brandes et al., 2012, Brandes & Winsemann, 2013). Numerical simulations support the results regarding the timing of the the seismicity and imply that the Late Pleistocene activity of the Osning Thrust was an effect of glacial isostatic adjustment (Brandes et al., 2012). In a second step we analysed more faults in northern Central Europe. It is evident that the historic seismicity was concentrated along major reverse faults that formerly played an important role during a tectonic contraction phase that effected Central Europe in the Late Cretaceous. Between these faults, the seismic activity was almost absent. Many of the historic earthquakes concentrated for a certain time along one fault and there is even evidence for distinct earthquake clusters in northern Central Europe e.g. along the Osning Thrust, the Aller Valley Fault and the Tornquist Zone. The spatial and temporal distribution of earthquakes (clusters that shift from time to time) implies that northern Central Europe behaves like a typical intraplate tectonic region. To analyse, if the faults that show pronounced historic seismicity are postglacial faults, we used the Fault Stability Margin (FSM), which is described in more detail in Wu & Hasegawa (1996). The Fault Stability Margins for the major reverse faults that showed historic seismicity in northern Central Europe reach the δFSM=0

  2. Long term gravity change and rapid uplifting caused by glacial isostatic adjustment in southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Miura, S.; Sato, T.; Sun, W.; Sugano, T.; Kaufman, A. M.; Freymueller, J. T.; Fujimoto, H.

    2007-12-01

    Glaciers at high latitudes are considered to be extremely sensitive to climate change and thus monitoring of glaciers is a clue to evaluate the future effect of global warming and the related phenomena. Ice mass changes also produce a time-variable surface load and give us useful data to investigate subsurface structure of the earth, especially to constrain the flow characteristics of the mantle. Larsen et al. (EPSL05) have extensively studied on vertical crustal movement in SE Alaska by means of raised shorelines, tide gauge measurements, and GPS to reveal the world¡¦s fastest glacial isostatic uplifting, which can be attributed to the response associated with glacier retreat. Displacement data, however, can only be used to constrain the sum of the elastic response to present-day ice melting (PDIM) and the viscoelastic one to past changes in ice. A Japan-US joint research project, ISEA (International geodetic research project in SouthEast Alaska), was initiated in 2005 to add new geodetic data sets and to refine the viscoelastic model derived by the previous studies. The outline of the project and some results are presented in this paper. In June, 2006, three kinds of field work were carried out. Absolute gravity (AG) surveys were performed at five sites in and around Glacier Bay using a Micro-g LaCoste absolute gravimeter, FG5#111 (Bilham and Sasagawa, EOS94). Gravity tide (GT) observation using a Scintrex¡¦s CG3M gravimeter was started in the campus of University of Alaska, Southeast (Sato et al., this meeting) to give precise corrections for the effect of ocean tide loading, which are the keys to increase the observation accuracy of AG and GPS. New continuous GPS (CGPS) sites were also established to examine not only the secular uplifting but the possible seasonal variation due to snow loading in the winter and ice loss in the summer. In December, 2006, another gravimeter, LaCoste and Romberg G-type #578, for GT observation with an electrostatic feedback

  3. Glacial isostatic adjustment model with composite 3-D Earth rheology for Fennoscandia

    NASA Astrophysics Data System (ADS)

    van der Wal, Wouter; Barnhoorn, Auke; Stocchi, Paolo; Gradmann, Sofie; Wu, Patrick; Drury, Martyn; Vermeersen, Bert

    2013-07-01

    Models for glacial isostatic adjustment (GIA) can provide constraints on rheology of the mantle if past ice thickness variations are assumed to be known. The Pleistocene ice loading histories that are used to obtain such constraints are based on an a priori 1-D mantle viscosity profile that assumes a single deformation mechanism for mantle rocks. Such a simplified viscosity profile makes it hard to compare the inferred mantle rheology to inferences from seismology and laboratory experiments. It is unknown what constraints GIA observations can provide on more realistic mantle rheology with an ice history that is not based on an a priori mantle viscosity profile. This paper investigates a model for GIA with a new ice history for Fennoscandia that is constrained by palaeoclimate proxies and glacial sediments. Diffusion and dislocation creep flow law data are taken from a compilation of laboratory measurements on olivine. Upper-mantle temperature data sets down to 400 km depth are derived from surface heatflow measurements, a petrochemical model for Fennoscandia and seismic velocity anomalies. Creep parameters below 400 km are taken from an earlier study and are only varying with depth. The olivine grain size and water content (a wet state, or a dry state) are used as free parameters. The solid Earth response is computed with a global spherical 3-D finite-element model for an incompressible, self-gravitating Earth. We compare predictions to sea level data and GPS uplift rates in Fennoscandia. The objective is to see if the mantle rheology and the ice model is consistent with GIA observations. We also test if the inclusion of dislocation creep gives any improvements over predictions with diffusion creep only, and whether the laterally varying temperatures result in an improved fit compared to a widely used 1-D viscosity profile (VM2). We find that sea level data can be explained with our ice model and with information on mantle rheology from laboratory experiments

  4. 7 CFR 58.421 - Press.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Press. 58.421 Section 58.421 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE...

  5. Does Science Get the Press It Deserves?

    ERIC Educational Resources Information Center

    Wilkie, Tom

    1991-01-01

    Discusses concerns about public understanding of science in the United Kingdom in relation to structure and content of newspapers, particularly the inadequacy of the press to be a vehicle for promoting scientific literacy within the citizenry. Argues that changes in science coverage by the media must originate from the scientific community with…

  6. When International Press Rights "Are" the News

    ERIC Educational Resources Information Center

    Freedman, Eric

    2006-01-01

    In many countries, reporters and editors face criminal prosecution, censorship, self-censorship, exile, tax audits, loss of broadcast and publication licenses, loss of jobs, assault, and even assassination based on how they practice their profession. Press rights and human rights advocacy groups try to draw media and official attention to those…

  7. Press Site Auditorium dedicated to John Holliman

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A ceremony dedicated the KSC Press Site auditorium as the John Holliman Auditorium to honor the correspondent for his enthusiastic, dedicated coverage of America's space program. The auditorium was built in 1980 and has been the focal point for new coverage of Space Shuttle launches. The ceremony followed the 94th launch of a Space Shuttle, on mission STS-96, earlier this morning.

  8. Research Review: The Specialized Business Press.

    ERIC Educational Resources Information Center

    Endres, Kathleen L.

    1994-01-01

    Reviews scholarly research (from journalism, communication, business, and the humanities) on the specialized business press. Notes the lack of theory building and ties across disciplines, and anticipates that new advances in CD-ROM technology may increase research into the field as well as strengthen ties across disciplines. (SR)

  9. An Introduction to Bibliographical Press Work.

    ERIC Educational Resources Information Center

    Richardson, John V., Jr.

    This guide to the literature of bibliographical press work is comprised of brief introductory notes on the field and this bibliography, followed by citations listed in seven categories: (1) book production, (2) handmade paper, (3) printer's ink, (4) type design, (5) book design, (6) hand printing, and (7) hand bookbinding. Introductory as well as…

  10. U.S. BICENTENNIAL EXPOSITION PRESS CONFERENCE

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Fielding questions from the press concerning 3rd Century America, the Bicentennial Exposition on Science and Technology are [left to right]: Herbert J. Rowe, NASA Associate Administrator for External Affairs; Miles Ross, KSC Deputy Director and Bicentennial General Manager; Lee Scherer, KSC Director, and Paul Donnelly, KSC Director of Space Transportation System Processing and Chief of the Exposition Site Development and Operations Office.

  11. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a... shall notify all news media representatives who have requested interviews or visits that have not been... national and international news services; (2) The television and radio networks and outlets; (3) The...

  12. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a... shall notify all news media representatives who have requested interviews or visits that have not been... national and international news services; (2) The television and radio networks and outlets; (3) The...

  13. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a... shall notify all news media representatives who have requested interviews or visits that have not been... national and international news services; (2) The television and radio networks and outlets; (3) The...

  14. Student Press Corps (Use the News).

    ERIC Educational Resources Information Center

    Mahler, Susan

    1989-01-01

    Describes the Student Press Corps, a program in which high school students submit weekly columns concerning local high school events for editing and possible publication by the local newspaper. Reports that training sessions have been fully enrolled for two years and that all participants are extremely positive about the program. (RS)

  15. Being Black in America: The Press Portrayal.

    ERIC Educational Resources Information Center

    Martindale, Carolyn

    Acknowledging inadequacies of press coverage of black Americans during this century, a study examined how a medium sized Ohio daily newspaper covered blacks before, during, and after the civil rights movement. Items concerning blacks in 66 issues of the Youngstown "Vindicator" from the 1950s, 1960s, and 1970s were studied, and the findings…

  16. Strategic Elites, the Press, and Race Relations.

    ERIC Educational Resources Information Center

    Domke, David

    2000-01-01

    Examines 2 important congressional debates about race relations, and the relationship of journalism to these debates, in the late 19th century. Suggests that political elites commonly used news, opinion, and perceptions in press content and by journalists to support, defend, and buttress certain policy positions in these debates. (SR)

  17. Free Press in a Constitutional Democracy

    ERIC Educational Resources Information Center

    Lucianek, Christine

    2014-01-01

    This article describes a lesson in which students will examine several views expressed by the founders to understand the context for including freedom of the press in the First Amendment. Students will be asked to think about the role that the news media and the need to be an informed citizen continue to play in our democracy. Students will…

  18. A Journalist's Guide to the Free Press.

    ERIC Educational Resources Information Center

    Ingelhart, Louis

    1996-01-01

    Summarizes the content of the federal constitution and various state constitutions regarding freedom of the press. Examines certain borderline issues, including actions and expressions, pornography, defamation, libel, and copyrighted material. States that regulation of unprotected material must be reasonable, specific, and clear. Discusses what…

  19. Communications in Agriculture: The American Farm Press.

    ERIC Educational Resources Information Center

    Evans, James F.; Salcedo, Rodolfo N.

    This book studies communications in agriculture, focusing on the American farm press. As defined here, a commercial farm periodical is directed to farmers and supports itself through the sale of subscriptions or advertising. It includes local as well as regional and national periodicals. A 90-year analysis, from 1880 to 1970, was chosen because…

  20. 7 CFR 58.421 - Press.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Press. 58.421 Section 58.421 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE...

  1. The Press Conferences of Eleanor Roosevelt.

    ERIC Educational Resources Information Center

    Beasley, Maurine H.

    Newly discovered transcriptions of 87 of First Lady Eleanor Roosevelt's women-only press conferences held from 1933 to 1945 make possible an examination of the objectives, topics, and value of these conferences. By holding the conferences, Mrs. Roosevelt attributed to women an important function in the political communication process, and at the…

  2. College Student Press Law. Second Edition.

    ERIC Educational Resources Information Center

    Trager, Robert; Dickerson, Donna L.

    This second edition of a monograph provides updated information on court decisions concerning college student publications and underground newspapers to acquaint advisers, administrators, and students with college student press law. Chapters of the monograph examine freedom of speech on the college campus; the relationship between colleges and…

  3. The Press, Privacy, and Community Mores.

    ERIC Educational Resources Information Center

    Glasser, Theodore L.

    Because of judicial indifference and legislative inaction, the conflict between the right of privacy and the freedom of the press is no closer to a resolution than it was a century ago. William Prosser's reduction of the common law of privacy into four separate torts has not solved the problem. The concept of "newsworthiness" has not been helpful…

  4. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a... shall notify all news media representatives who have requested interviews or visits that have not been... national and international news services; (2) The television and radio networks and outlets; (3) The...

  5. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a... shall notify all news media representatives who have requested interviews or visits that have not been... national and international news services; (2) The television and radio networks and outlets; (3) The...

  6. STS-9 Spacelab 1 Press Kit

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Press information on the STS-9/SPACELAB 1 mission is provided. Launch preparations, launch window, flight objectives, experiments, life sciences baseline data collection, SPACELAB 1 payload operations and control crew and specialists, and tracking and data management are among the topics explained.

  7. Holding fixture for a hot stamping press

    NASA Technical Reports Server (NTRS)

    Harris, R. P. (Inventor)

    1983-01-01

    A hand held guide for manually positioning a work piece between the anvil rib and tool of a hot die stamping press is described. A groove completed by interchangeable cover plates attached at one end of the guide conforms to a cross sectional dimension common to similar workpieces and, with a force fit, retentively holds each of the workpieces.

  8. Eye-Pressing by Visually Impaired Children.

    ERIC Educational Resources Information Center

    Jan, James E.; And Others

    1983-01-01

    The nature of eye-pressing as a visual stimulation mannerism in children with severely impaired eyesight is examined, and a possible physiological explanation (that self-stimulation occurs when the demand of the brain for meaningful visual information is not met) is offered. (CL)

  9. Accuracy of Press Reports in Astronomy

    NASA Astrophysics Data System (ADS)

    Schaefer, B. E.; Hurley, K.; Nemiroff, R. J.; Branch, D.; Perlmutter, S.; Schaefer, M. W.; Consolmagno, G. J.; McSween, H.; Strom, R.

    1999-12-01

    Most Americans learn about modern science from press reports, while such articles have a bad reputation among scientists. We have performed a study of 403 news articles on three topics (gamma-ray astronomy, supernovae, and Mars) to quantitatively answer the questions 'How accurate are press reports of astronomy?' and 'What fraction of the basic science claims in the press are correct?' We have taken all articles on the topics from five news sources (UPI, NYT, S&T, SN, and 5 newspapers) for one decade (1987-1996). All articles were evaluated for a variety of errors, ranging from the fundamental to the trivial. For 'trivial' errors, S&T and SN were virtually perfect while the various newspapers averaged roughly one trivial error every two articles. For meaningful errors, we found that none of our 403 articles significantly mislead the reader or misrepresented the science. So a major result of our study is that reporters should be rehabilitated into the good graces of astronomers, since they are actually doing a good job. For our second question, we rated each story with the probability that its basic new science claim is correct. We found that the average probability over all stories is 70%, regardless of source, topic, importance, or quoted pundit. How do we reconcile our findings that the press does not make significant errors yet the basic science presented is 30% wrong? The reason is that the nature of news reporting is to present front-line science and the nature of front-line science is that reliable conclusions have not yet been reached. So a second major result of our study is to make the distinction between textbook science (with reliability near 100%) and front-line science which you read in the press (with reliability near 70%).

  10. Kiln for hot-pressing compacts in a continuous manner

    DOEpatents

    Reynolds, C.D Jr.

    1983-08-08

    The invention is directed to a hot pressing furnace or kiln which is capable of preheating, hot pressing, and cooling a plurality of articles in a sequential and continuous manner. The hot pressing furnace of the present invention comprises an elongated, horizontally disposed furnace capable of holding a plurality of displaceable pusher plates each supporting a die body loaded with refractory or ceramic material to be hot pressed. Each of these plates and the die body supported thereby is sequentially pushed through the preheating zone, a temperature stabilizing and a hot pressing zone, and a cooling zone so as to provide a continuous hot-pressing operation of a plurality of articles.

  11. Kiln for hot-pressing compacts in a continuous manner

    DOEpatents

    Reynolds, Jr., Carl D.

    1985-01-01

    The present invention is directed to a hot pressing furnace or kiln which is capable of preheating, hot pressing, and cooling a plurality of articles in a sequential and continuous manner. The hot pressing furnace of the present invention comprises an elongated, horizontally disposed furnace capable of holding a plurality of displaceable pusher plates each supporting a die body loaded with refractory or ceramic material to be hot pressed. Each of these plates and the die body supported thereby is sequentially pushed through the preheating zone, a temperature stabilizing and a hot pressing zone, and a cooling zone so as to provide a continuous hot-pressing operation of a plurality of articles.

  12. 9. INTERIOR VIEW OF EYE PRESS AREA; TO LEFT IS ...

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

    9. INTERIOR VIEW OF EYE PRESS AREA; TO LEFT IS A TWO-BAY SLOTTED TYPE FURNACE, TO CENTER IS EYE PRESS, TO RIGHT IS CURCULAR SAW - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  13. 19. VIEW OF MOUNTING PRESS, showing removal of water guard ...

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

    19. VIEW OF MOUNTING PRESS, showing removal of water guard prior to dismounting from press. Gary Stich, operator. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  14. Low-angle normal faulting and isostatic response in the Gulf of Suez: Evidence from seismic interpretation and geometric reconstruction

    NASA Technical Reports Server (NTRS)

    Perry, S. K.; Schamel, S.

    1985-01-01

    Tectonic extension within continental crust creates a variety of major features best classed as extensional orogens. These features have come under increasing attention in recent years, with the welding of field observation and theoretical concepts. Most recent advances have come from the Basin and Range Province of the southwestern United States and from the North Sea. Application of these geometric and isostatic concepts, in combination with seismic interpretation, to the southern Gulf of Suez, an active extensional orogen, allows generation of detailed structural maps and geometrically balanced sections which suggest a regional structural model. Geometric models which should prove to be a valuable adjunct to numerical and thermal models for the rifting process are discussed.

  15. Method for hot pressing beryllium oxide articles

    DOEpatents

    Ballard, Ambrose H.; Godfrey, Jr., Thomas G.; Mowery, Erb H.

    1988-01-01

    The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

  16. Reducing VOC Press Emission from OSB Manufacturing

    SciTech Connect

    Dr. Gary D. McGinnis; Laura S. WIlliams; Amy E. Monte; Jagdish Rughani: Brett A. Niemi; Thomas M. Flicker

    2001-12-31

    Current regulations require industry to meet air emission standards with regard to particulates, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and other gases. One of many industries that will be affected by the new regulations is the wood composites industry. This industry generates VOCs, HAPs, and particulates mainly during the drying and pressing of wood. Current air treatment technologies for the industry are expensive to install and operate. As regulations become more stringent, treatment technologies will need to become more efficient and cost effective. The overall objective of this study is to evaluate the use of process conditions and chemical additives to reduce VOC/HAPs in air emitted from presses and dryers during the production of oriented strand board.

  17. [Ashi points, Ashi method and pressing reaction].

    PubMed

    Wang, Zhao-hui; Zhang, Zhi-feng; Ding, Xiao-jun; Zhou, Chang-le

    2011-04-01

    The nomination of Ashi points was reviewed, and the meaning of Ashi method was discussed in this article. On the base of further study on Huangdi Neijing (The Yellow Emperor's Canon of Internal Medicine), the general meaning of palpation at acupoints, meridians and collaterals to the process of acupoint locating were expounded. The concept of pressing reaction was proposed as well. It is held that Ashi points are a category of acupoints without specific names and definite locations. They are a kind of manifestation of reactions of acupoints, meridians and collaterals, which embody their dynamic features. Pressing reaction mainly manifested by sensations of comfort, pain, and moreover, relieving of the primary symptoms. It is the most basic evidence for us to estimate Ashi points. PMID:21528600

  18. NKG201xGIA - first results for a new model of glacial isostatic adjustment in Fennoscandia

    NASA Astrophysics Data System (ADS)

    Steffen, Holger; Barletta, Valentina; Kollo, Karin; Milne, Glenn A.; Nordman, Maaria; Olsson, Per-Anders; Simpson, Matthew J. R.; Tarasov, Lev; Ågren, Jonas

    2016-04-01

    Glacial isostatic adjustment (GIA) is a dominant process in northern Europe, which is observed with several geodetic and geophysical methods. The observed land uplift due to this process amounts to about 1 cm/year in the northern Gulf of Bothnia. GIA affects the establishment and maintenance of reliable geodetic and gravimetric reference networks in the Nordic countries. To support a high level of accuracy in the determination of position, adequate corrections have to be applied with dedicated models. Currently, there are efforts within a Nordic Geodetic Commission (NKG) activity towards a model of glacial isostatic adjustment for Fennoscandia. The new model, NKG201xGIA, to be developed in the near future will complement the forthcoming empirical NKG land uplift model, which will substitute the currently used empirical land uplift model NKG2005LU (Ågren & Svensson, 2007). Together, the models will be a reference for vertical and horizontal motion, gravity and geoid change and more. NKG201xGIA will also provide uncertainty estimates for each field. Following former investigations, the GIA model is based on a combination of an ice and an earth model. The selected reference ice model, GLAC, for Fennoscandia, the Barents/Kara seas and the British Isles is provided by Lev Tarasov and co-workers. Tests of different ice and earth models will be performed based on the expertise of each involved modeler. This includes studies on high resolution ice sheets, different rheologies, lateral variations in lithosphere and mantle viscosity and more. This will also be done in co-operation with scientists outside NKG who help in the development and testing of the model. References Ågren, J., Svensson, R. (2007): Postglacial Land Uplift Model and System Definition for the New Swedish Height System RH 2000. Reports in Geodesy and Geographical Information Systems Rapportserie, LMV-Rapport 4, Lantmäteriet, Gävle.

  19. Graphic Arts: The Press and Finishing Processes. Third Edition.

    ERIC Educational Resources Information Center

    Crummett, Dan

    This document contains teacher and student materials for a course in graphic arts concentrating on printing presses and the finishing process for publications. Seven units of instruction cover the following topics: (1) offset press systems; (2) offset inks and dampening chemistry; (3) offset press operating procedures; (4) preventive maintenance…

  20. Freedom of the Press in an International Perspective. Teaching Strategy.

    ERIC Educational Resources Information Center

    Miller, Barbara

    1997-01-01

    Presents a lesson plan that compares freedom of the press in the United States and other countries. Reveals the extent to which the First Amendment protects press freedom from abuses found in other countries. Includes a world map illustrating areas enjoying freedom of the press, and related statistical tables. (MJP)

  1. Through the Looking Glass: Press Responses to Genocide.

    ERIC Educational Resources Information Center

    Lipstadt, Deborah E.

    1991-01-01

    Examines press coverage of the Holocaust to analyze the response of the United States and the world to the Jewish extermination. Compares this coverage to earlier press responses to the Armenian genocide and Ukraine famines. Argues the press was unwilling to face the Holocaust's magnitude. Urges teachers to teach about the Holocaust and similar…

  2. The Rice University Press Initiative: An Interview with Charles Henry

    ERIC Educational Resources Information Center

    Trevitte, Chad; Henry, Charles

    2007-01-01

    In this interview Charles Henry, publisher of the Rice University Press (RUP), discusses RUP's rebirth as a fully digital university press. Henry addresses the circumstances that led to this decision, and he further outlines the RUP business model whereby the press will publish its own titles--both digitally and in print-on-demand--while…

  3. The Press, Japanese Americans, and the Concentration Camps.

    ERIC Educational Resources Information Center

    Okihiro, Gary Y.; Sly, Julie

    1983-01-01

    A study of the wartime press suggests that the plan to incarcerate Japanese Americans (under Executive Order 9066) was government-initiated, that the public and the press initially disapproved of such treatment, and that events emanating from the government influenced shifts in press and public opinion that allowed implementation of the plan.…

  4. Living Dangerously--Changing Press Law in India.

    ERIC Educational Resources Information Center

    Ryan, Timothy

    An examination of the changes in press laws after India gained its independence in 1947 shows how a free press is shaped mostly by the structure and evolution of the democratic society that it is intended to serve. The most salient features that have characterized the Indian press, from the early nineteenth century to the present day, are…

  5. The American Native Press and American Indian Studies.

    ERIC Educational Resources Information Center

    Littlefield, Daniel F., Jr.

    1986-01-01

    As product and process, the Native American press has a long history. The establishment of the first native-run press in 1828 began a press history that continues today. That history is represented by more than 2,000 periodical titles alone, two-thirds of which have been established during the past 20 years. Impressive collections of these…

  6. The Historical Importance of Jury to Press Freedom.

    ERIC Educational Resources Information Center

    Olasky, Marvin N.

    Staggered by some recent libel verdicts, many journalists are neglecting lessons about press freedom learned at great cost during the seventeenth and eighteenth centuries. Journalists then learned that state power over the press, residing in the hands of either censors or judges, leads to a decrease in press freedom. In 1986, though, many media…

  7. The Inter American Press Association as Champion of Press Freedom: Reality or Rhetoric? The Bolivian Experience, 1952-1973.

    ERIC Educational Resources Information Center

    Knudson, Jerry W.

    Each year a committee on freedom of the press, established in 1946 by the Inter American Press Association (IAPA), exposes those countries which it feels do not have freedom of the press. In 1952 Bolivia underwent a social and economic revolution. As a result, angry mobs forced the closure of the two newspapers with the largest circulation in…

  8. 17 CFR 230.135e - Offshore press conferences, meetings with issuer representatives conducted offshore, and press...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RULES AND REGULATIONS, SECURITIES ACT OF 1933 General § 230.135e Offshore press conferences, meetings... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Offshore press conferences, meetings with issuer representatives conducted offshore, and press-related materials released offshore....

  9. Effect of hot pressing additives on the leachability of hot pressed sodium hydrous titanium oxide

    SciTech Connect

    Valentine, T.M.; Sambell, R.A.J.

    1980-01-01

    Sodium hydrous titanium oxide is an ion exchange resin which can be used for immobilizing medium level waste (MLW) liquors. When hot pressed, it undergoes conversion to a ceramic. Three low melting point materials (borax, bismuth trioxide, and a mixture of PbO/CuO) were added to the (Na)HTiO and the effect that each of these had on aiding densification was assessed. Hot pressing temperature, applied pressure, and percentage addition of hot pressing aid were varied. Percentage open porosity, flexural strength, and leachability were measured. There was a linear relationship between the percentage open porosity and the logarithm of the leach rate for a constant percentage addition of each additive.

  10. EX-PRESS Glaucoma Filtration Device: efficacy, safety, and predictability

    PubMed Central

    Chan, Jessica E; Netland, Peter A

    2015-01-01

    Trabeculectomy has been the traditional primary surgical therapy for open-angle glaucoma. While trabeculectomy is effective in lowering intraocular pressure, complications associated with the procedure have motivated the development of alternative techniques and devices, including the EX-PRESS Glaucoma Filtration Device. This review describes the efficacy, safety, complication rates, and potential advantages and disadvantages of the EX-PRESS Glaucoma Filtration Device. EX-PRESS implantation is technically simpler compared with that of trabeculectomy, with fewer surgical steps. Vision recovery has been more rapid after EX-PRESS implantation compared with trabeculectomy. Intraocular pressure variation is lower during the early postoperative period, indicating a more predictable procedure. While efficacy of the EX-PRESS implant has been comparable to trabeculectomy, postoperative complications appear less common after EX-PRESS implantation compared with trabeculectomy. The EX-PRESS Glaucoma Filtration Device appears to be safe and effective in the surgical management of open-angle glaucoma. PMID:26366105

  11. Method for hot press forming articles

    DOEpatents

    Baker, Robert R.; Hartsock, Dale L.

    1982-01-01

    This disclosure relates to an improved method for achieving the best bond strength and for minimizing distortion and cracking of hot pressed articles. In particular, in a method for hot press forming both an outer facing circumferential surface of and an inner portion of a hub, and of bonding that so-formed outer facing circumferential surface to an inner facing circumferential surface of a pre-formed ring thereby to form an article, the following improvement is made. Normally, in this method, the outside ring is restrained by a restraining sleeve of ring-shaped cross-section having an inside diameter. A die member, used to hot press form the hub, is so-formed as to have an outside diameter sized to engage the inside diameter of the restraining sleeve in a manner permitting relative movement therebetween. The improved method is one in which several pairs of matched restraining sleeve and die member are formed with each matched pair having a predetermined diameter. The predetermined diameter of each matched pair is different from another matched pair by stepped increments. The largest inside diameter of a restraining sleeve is equal to the diameter of the outer facing circumferential surface of the hub. Each pair of the matched restraining sleeve and die member is used to form an article in which an inside hub is bonded to an outside ring. The several samples so-formed are evaluated to determine which sample has the best bond formed between the hub and the ring with the least or no cracking or distortion in the ring portion of the article. Thereafter, the matched restraining sleeve and die member which form the article having the best bonding characteristics and least distortion cracking is then used for repeated formations of articles.

  12. Press Site Auditorium dedicated to John Holliman

    NASA Technical Reports Server (NTRS)

    1999-01-01

    From left, Center Director Roy Bridges and NASA Administrator Daniel S. Goldin applaud as Jay Holliman, with the help of his mother, Mrs. Dianne Holliman, unveils a plaque honoring his father, the late John Holliman. At right is Tom Johnson, news group chairman of CNN. The occasion was the dedication of the KSC Press Site auditorium as the John Holliman Auditorium to honor the CNN national correspondent for his enthusiastic, dedicated coverage of America's space program. The auditorium was built in 1980 and has been the focal point for new coverage of Space Shuttle launches. The ceremony followed the 94th launch of a Space Shuttle, on mission STS-96, earlier this morning.

  13. Press Site Auditorium dedicated to John Holliman

    NASA Technical Reports Server (NTRS)

    1999-01-01

    NASA Administrator Daniel S. Goldin hands Mrs. Dianne Holliman a plaque honoring her late husband, John Holliman, a CNN national correspondent. Standing behind Goldin is Center Director Roy Bridges. At right is Tom Johnson, news group chairman of CNN. A ceremony dedicated the KSC Press Site auditorium as the John Holliman Auditorium to honor the correspondent for his enthusiastic, dedicated coverage of America's space program. The auditorium was built in 1980 and has been the focal point for new coverage of Space Shuttle launches. The ceremony followed the 94th launch of a Space Shuttle, on mission STS-96, earlier this morning.

  14. STS-99 / Endeavour: Launch Postponement Press Conference

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Live footage shows Ron Dittemore, the Shuttle Program Manager from Johnson Space Center (JSC), participating in a Launch Postponement Press Conference disclosing the status of the STS-99 flight. He addresses the weather condition which caused the postponement and the erroneous response from one of the Master Events Controllers (MEC). The moderator of this conference is Bruce Buckingham from NASA's Public Affairs Office. Ron answers questions from the audience about the MEC responsible for sending commands for launch, and the implications that it might have on the launch schedule.

  15. Abstracts of Suburban Press Critique Series Papers Produced by the Suburban Press Research Center from April 1966 to May 1973. Suburban Press Research Series No. 15.

    ERIC Educational Resources Information Center

    Northern Illinois Univ., De Kalb. Suburban Press Research Center.

    Abstracts of 28 articles, collected by the Suburban Press Research Center, are provided in this paper. The articles discuss various aspects of the suburban press: pretrial coverage; news coverage for adolescents, the family, and the aged; editorials; education news; business news; crime coverage; consumer information; the formation of policies…

  16. The Ebb and Flow of the Liberalization of the Jordanian Press: 1985-1997.

    ERIC Educational Resources Information Center

    Najjar, Orayb Aref

    1998-01-01

    Contributes to scholarship on the complexities of press freedom in non-Western nations. Discusses the context of press freedom in Jordan; the press before the 1989 liberalization; factors that favored press liberalization in 1989; the 1993 press law; the "Temporary Law for the Year 1997"; press reaction to the amendments; and factors mitigating…

  17. Apollo 11 Astronauts During Press Conference

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The night before launch day, Apollo 11 crew members (R-L) Michael Collins, Neil Armstrong, and Edwin Aldrin, participated in a closed circuit press conference the night before they began their historic lunar landing mission. At far left is chief astronaut and director of flight crew operations, Donald K. Slayton. The press conference with questions via intercom, was held under semi-isolation conditions to avoid exposing the astronauts to possible illness at the last minute. The Apollo 11 mission, the first lunar landing mission, launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.

  18. Direct drive digital servo press with high parallel control

    NASA Astrophysics Data System (ADS)

    Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

    2013-12-01

    Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than μm order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

  19. Post flight press conference for the STS-7 mission

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Two of the three mission specialists for STS-7 field questions from the press during the post-flight press conference in JSC's main auditorium on July 1, 1983. Left to right are John M. Fabian and Dr. Norman E. Thagard (35419); Portrait view of Fabian during the STS-7 post-flight press conference (35420); Portrait view of mission specialist Dr. Sally K. Ride during the STS-7 post-flight press conference (35421); Portrait view of STS-7 pilot Frederick H. Hauck during the post-flight press conference (35422); Portrait view of STS-7 crew commander Robert L. Crippen during the post-flight press conference (35423); Three STS-7 crew members listen to questions from news reporters. They are, left to right, Crippen, Hauck, and Ride (35424); The first five person shuttle crew and first woman crew member greet the news media. Members are, left to right, Crippen, Hauck, Ride, Fabian and Thagard (35425).

  20. Geodetically-Constrained Glacial Isostatic Adjustment models of Antarctica: Implications for the Mass Balance of the West Antarctic Ice Sheet

    NASA Astrophysics Data System (ADS)

    Willis, M. J.; Wilson, T. J.; James, T. S.; Mazzotti, S.; Bevis, M. G.; Kendrick, E. C.; Brown, A. K.

    2010-12-01

    The IJ05 Antarctic ice sheet history is employed to drive a suite of approximately one thousand two-layered, laterally-homogeneous spherical Earth models and generate predictions of Antarctic crustal uplift due to glacial isostatic adjustment (GIA). GPS data collected between 1996 and 2010 on the flanks of the West Antarctic Rift System are used to produce bedrock uplift rates that are compared with the model predictions. The models that display the best fit to the data have softer, weaker upper-mantle viscosities than those published in many previous studies. A low viscosity upper-mantle is in agreement with seismic tomography that indicates that the upper mantle beneath much of West Antarctica has slower than average seismic shear-wave velocities. Best fit models further feature thin elastic lithospheres, a situation that is also corroborated by recent airborne gravity and seismic investigations. The best fit GIA models are used to generate crustal uplift rates and gravity changes that are larger than previously published models used to correct GRACE observations and infer Antarctic ice mass balance.The new models, which are the first GPS-constrained GIA corrections for GRACE in Antarctica, increases the ice-mass loss estimate for West Antarctica.

  1. Spectral assessment of isostatic gravity models against CHAMP, GRACE, GOCE satellite-only and combined gravity models

    NASA Astrophysics Data System (ADS)

    Tsoulis, Dimitrios; Patlakis, Konstantinos

    2014-08-01

    The availability of digital elevation databases representing the topographic and bathymetric relief with global homogeneous coverage and increasing resolution permits the computation of crust-related Earth gravity models, the so-called topographic/isostatic Earth gravity models (henceforth T/I models). Although expressing the spherical harmonic content of the topographic masses, the interpretation purpose of T/I models has not been given the attention it deserves, apart from the fact that they express some degree of compensation to the observed spectrum of the topographic heights, depending on the kind of the applied compensation mechanism. The present contribution attempts to improve the interpretation aspects of T/I Earth gravity models. To this end, a rigorous spectral assessment is performed to a standard Airy/Heiskanen T/I model against different CHAllenging Minisatellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE), Gravity field and steadystate Ocean Circulation Explorer (GOCE) satellite-only, and combined gravity models. Different correlation bandwidths emerge for these four groups of satellite-based gravity models. The band-limited forward computation of the models using these bandwidths reproduces nicely the main features of the applied T/I model.

  2. The Multianvil Press Research Facility at GSECARS

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Uchida, T.; Rivers, M. L.; Sutton, S. R.; Weidner, D. J.; Durham, W. B.

    2002-12-01

    The multianvil press high pressure synchrotron research facility at the GSECARS beamlines consists of two large-volume presses (LVP): a 2.5 MN (250 ton) system at the bending magnet beamline (13-BM-D) and a 10 MN system at the insertion device beamline (13-ID-D). Both systems are now fully operational, with steadily increasing annual usage from ~70 days in 1998 to ~120 days in 2001. Here we present a system overview with brief scientific highlights illustrating the breadth of research and achievements made using this facility. Construction and operation of the facility are supported by the NSF Geosciences Instrumentation and Facilities Program. A DIA-type cubic-anvil apparatus and a split-cylinder apparatus (T-Cup) with 10 mm WC cubes are used to generate pressures and temperatures up to 24 GPa and 2400 K, on millimeter-sized samples, at 13-BM-D. In 13-ID-D, a large T-Cup apparatus with 25 mm anvils is used to reach pressure and temperature conditions of 25 GPa and 2500K simultaneously. Both high-pressure apparatus are mounted in die-sets, which can be easily transported in and out of the hydraulic press. Therefore all pressure generating apparatus can be used at any beamline, depending on research needs. A new deformation DIA (DDIA) was commissioned in August, 2002. This apparatus is capable of generating 30% strain on a 1 mm sample at pressures to ~15 GPa, allowing quantitative triaxial deformation experiments. Close to 400 runs have been carried out at our facility in a wide range of research areas: (1) P-V-T equation of state measurements on important mantle minerals, Fe alloys, and pressure standards, (2) in situ determination of phase relations of silicates, Fe alloys, and semiconductors using X-ray diffraction, (3) falling sphere measurements using radiography to determine viscosity of the silicate and metallic melts, (4) ultrasonic velocity measurements on mantle minerals, especially non-quenchable high pressure phases (e.g., high-pressure clinoenstatite

  3. 30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROWGUAGE ...

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

    30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROW-GUAGE GONDOLA CAR IN LEFT BACKGROUND BROUGHT MOISTENED GUN COTTON FROM REST HOUSE (BUILDING NO. 320-B) IN CANS. (ONE OF THESE CANS IS ON UNLOADING PLATFORM RUNNING BESIDE PRESSES). CONTENTS OF CANS WERE UNLOADED INTO PRESSES BY HAND. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  4. Assessment of the isostatic state and the load distribution of the European Molasse basin by means of lithospheric-scale 3D structural and 3D gravity modelling

    NASA Astrophysics Data System (ADS)

    Przybycin, Anna M.; Scheck-Wenderoth, Magdalena; Schneider, Michael

    2015-07-01

    The European Molasse basin is a foreland basin situated at the northern front of the European Alps and has formed as a consequence of the Euro-Adriatic continental collision since the Tertiary. Today, it is underlain by Mesozoic sedimentary successions on top of a Paleozoic crust. To investigate the deep structure, the isostatic state, as well as the load distribution in the basin and the adjacent Alpine area, we constructed a lithospheric-scale 3D structural model by implementing available surface, well and seismic data. Subsequently, the structure of the model was constrained by means of 3D gravity modelling. Complementary, the isostatic state has been assessed based on the calculation of the 3D load distribution. Our results show that the Molasse basin is not in isostatic equilibrium and that the gravity field of the area is strongly controlled by the configuration of the crystalline crust. Furthermore, we show that the area is influenced by significant lateral load variations down to a depth of -150 km, which are considerably larger than commonly assumed for this level. Furthermore, our results allow a first-order assessment of the minimum compensating horizontal stress required to prevent gravitational collapse.

  5. STS-114: Discovery Launch Postponement Press Briefing

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This press briefing addresses the problem that occurred prior to the launch of the STS-114. Dean Acosta, Deputy Assistant Administrator of Public Affairs, introduces the panel which consists of Dr. Michael Griffin, NASA Administrator, William Readdy, Associate Administrator for Space Operations, Wayne Hale, Space Shuttle Program Deputy Manager, Steve Poulas, Orbiter Project Manager, Mike Leinbach, NASA Launch Director, and Bill Parsons, Space Shuttle Program Manager. Wayne Hale expresses that a problem occurred with one of the low level sensors in the hydrogen tank and that the cause of the problem must be identified and rectified. Steve Poulos talks about establishing a troubleshooting plan as a part of the scrub effort and Mike Leinbach describes the process of draining the external tank. Wayne Hale answers questions about the sensors and if the Space Shuttle Discovery is safe to fly and Steve Poulos answers questions about the possible suspects for this problem.

  6. STS-114: Post Launch Press Conference

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Dean Acosta, Deputy Assistant Administrator for Public Affairs hosted this post launch press conference. Present were Mike Griffin, NASA Administrator; William Ready, Associate Administrator for Space Operations; Bill Parsons, Space Shuttle Program Manager; Mike Leinbach, NASA Launch Director; and Wayne Hill, Deputy Program Manager for Space Shuttle Program. Each expressed thanks to all of NASA Officials and employees, contractors, vendors and the crew for their hard work the past two and a half years that resulted the successful and pristine launch of Space Shuttle Discovery. The Panel emphasized that through extensive technical analysis, thorough planning and tremendous amount of public support brought them full circle again to return to flight. Flight safety, debris during rocket separation, sensors, observations from the mission control, launch conditions were some of the topics discussed with the News media.

  7. STS-103 Discovery Launch Scrub Press Conference

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A press conference held on December 16, 1999, to explain the reason behind NASA's decision to delay the Discovery's launching by a period of 24 hrs is presented. According to Ron Dittemore, Space Shuttle Program Manager, the STS-103 team delayed the launch because they need extra time to check one vendor's manufacturing processes, after an x-ray inspection revealed that an improper weld rod was used to weld one of the pressuring lines (called NPS lines) in the ET (external tank). Mr. Dittemore explained that since it is in the ET (not a major load carrying structure and rebuild after each flight), it did not pose any danger to the STS-103 flight. However, the same vendor also manufactured some parts of the orbiter and the team wanted to make sure that the quality of the vendor's manufacturing processes is robust before launching the orbiter to space. He also answered some reporters' questions.

  8. Publishing Outside the Box: Popular Press Books.

    PubMed

    Vyse, Stuart

    2014-10-01

    Writing and publishing popular press books requires a set of skills, not natural to basic and applied researchers trained to publish in peer-referred behavior analytic journals or to practice behavior analysis in applied settings. This article provides suggestions and examples. These include finding a distinctive idea, securing a contract, hiring an agent (or not), deciding on a publisher, and writing engagingly for a broad audience. The last is the greatest challenge. Among my recommendations are to read good prose, good models, and good books about publishing; talk to experienced colleagues; read aloud to judge the appropriateness of your vocabulary and style; and interject humor, imagery, and drama. Book publishing is a long and difficult process, but it is possible. It has a great potential for bringing behavior analytic research, practice and theory to the attention of the general public. PMID:27274959

  9. A comparative study between spiral-filter press and belt press implemented in a cloudy apple juice production process.

    PubMed

    De Paepe, Domien; Coudijzer, Katleen; Noten, Bart; Valkenborg, Dirk; Servaes, Kelly; De Loose, Marc; Diels, Ludo; Voorspoels, Stefan; Van Droogenbroeck, Bart

    2015-04-15

    In this study, advantages and disadvantages of the innovative, low-oxygen spiral-filter press system were studied in comparison with the belt press, commonly applied in small and medium size enterprises for the production of cloudy apple juice. On the basis of equivalent throughput, a higher juice yield could be achieved with spiral-filter press. Also a more turbid juice with a higher content of suspended solids could be produced. The avoidance of enzymatic browning during juice extraction led to an attractive yellowish juice with an elevated phenolic content. Moreover, it was found that juice produced with spiral-filter press demonstrates a higher retention of phenolic compounds during the downstream processing steps and storage. The results demonstrates the advantage of the use of a spiral-filter press in comparison with belt press in the production of a high quality cloudy apple juice rich in phenolic compounds, without the use of oxidation inhibiting additives. PMID:25466116

  10. Letting The Nasa Press Engine Work For You

    NASA Astrophysics Data System (ADS)

    Weaver, Kimberly A.

    2006-09-01

    You have an amazing result based on NASA data or a NASA mission, you have written your seminal paper and submitted it to your favorite journal. You believe it has press potential and maybe you've even gotten help from your PR folks in writing a press release. Now you would really like NASA to issue this as a press release. But how do you do that? This presentation will illustrate the steps required to engage NASA in helping promote your story. What are NASA's requirements for newsworthiness? Should your news be released as a web feature story or in the local media? Does your news rise to the level of a full-blown press conference or will it be a media teleconference? How do you obtain approval for a NASA press event? Once your result is scheduled to be issued as a press release, how can you improve your chances of getting the best possible coverage for your story? I will discuss the NASA press process and suggest how to consider factors like timing, working with your collaborating institutions in an efficient way, and not letting the cat out of the bag until the press event.

  11. 6. Interior, first floor front room. View of pressed metal ...

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

    6. Interior, first floor front room. View of pressed metal ceiling visible through opening in dropped ceiling. (Below the pressed metal ceiling are three wooden joists, two electrical wires and the edges of the dropped ceiling where a panel had been removed). - Ferree Building, 417 Ninth Street, Northwest, Washington, District of Columbia, DC

  12. New Realities for Scholarly Presses in Trying Economic Times

    ERIC Educational Resources Information Center

    Blakesley, David

    2014-01-01

    The author explains that Parlor Press is an independent publisher and distributor of scholarly and trade books in print and digital formats. It was founded in 2002 to address the need for an alternative scholarly, academic press attentive to emergent ideas and forms while maintaining the highest possible standards of quality, credibility, and…

  13. Westview Press: Small Is Beautiful--and Profitable.

    ERIC Educational Resources Information Center

    Evans, Nancy

    1979-01-01

    Westview Press in Boulder, Colorado, is a small independent press with an interest in scholarly publishing, especially manuscripts concerned with international and public policy. High speed and low cost are the advantages of its no-frills production method. A description of its operation and guidelines for authors are presented. (JMD)

  14. First Amendment Speech and Press Theory: Preferred Position Postulate Reexamined.

    ERIC Educational Resources Information Center

    Stonecipher, Harry W.

    If the United States Supreme Court is to exercise its historic role as guardian of the fundamental freedoms flowing from the speech and press clauses of the first amendment, it is imperative that those basic freedoms be placed in a preferred position. The preferred position doctrine provides adequate safeguards for both speech and press guarantees…

  15. 7. VIEW OF HYDRAULIC HAMMER STAMPING PRESS ON SIDE A ...

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

    7. VIEW OF HYDRAULIC HAMMER STAMPING PRESS ON SIDE A OF BUILDING 883. THIS TYPE OF PRESS WAS USED FOR BOTH STAINLESS STEEL AND FOR DEPLETED URANIUM. (7/2/86) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

  16. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Mechanical power presses. 1910.217 Section 1910.217 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.217 Mechanical power presses. (a) General requirements....

  17. Korean and Japanese Press: A Study in Crisis.

    ERIC Educational Resources Information Center

    Ruidl, Richard A.

    During a time of crisis, it is instructive to examine the national press of Japan and Korea, two economic allies that view each other with suspicion. The Japanese press is relatively free and liberal-oriented on the domestic scene but is closely aligned with big business and government with regard to international concerns. The South Korean…

  18. Press Conference with Elliot L. Richardson, Secretary of HEW.

    ERIC Educational Resources Information Center

    Department of Health, Education, and Welfare, Washington, DC.

    Two documents were released to the press on January 18, 1973, by Secretary Richardson, one summarizing his term of office as Secretary of Health, Education, and Welfare, and one reporting on HEW potential for the seventies (SO 005 666, SO 005 699). In an introductory statement prior to the press conference, the question of whether or not we as a…

  19. Criticism of the Press: Its Social, Psychological and Political Origins.

    ERIC Educational Resources Information Center

    Becker, Lee B.; And Others

    This study examines data from several national polls about press coverage during the Watergate scandal, in order to assess the origins of press criticism. The polls were conducted between 28 September and 6 October 1973, during June 1974, and in August 1974. The data suggest that political variables--particularly support of Nixon, party…

  20. 6. VIEW OF THE BRIQUETTING PRESS AND CHIP CLEANING HOOD. ...

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

    6. VIEW OF THE BRIQUETTING PRESS AND CHIP CLEANING HOOD. SCRAPS OF ENRICHED URANIUM FROM MACHINING OPERATIONS WERE CLEANED IN A SOLVENT BATH, THEN PRESSED INTO BRIQUETTS. THE BRIQUETTS WERE USED AS FEED MATERIAL FOR THE FOUNDRY. (4/4/66) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

  1. 9. DETAILED VIEW OF BRIQUETTING PRESS HOUSED IN A GLOVE ...

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

    9. DETAILED VIEW OF BRIQUETTING PRESS HOUSED IN A GLOVE BOX. THE PRESS FORMED SCRAP PLUTONIUM METAL FROM FOUNDRY AND FABRICATION PROCESSES INTO SMALL BRIQUETTES. THESE BRIQUETTES BECAME PART OF THE FEED MATERIALS FOR THE FOUNDRY. (5/6/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  2. 10. VIEW OF MODULE B, INSTALLATION OF A HYDRAULIC PRESS. ...

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

    10. VIEW OF MODULE B, INSTALLATION OF A HYDRAULIC PRESS. THE PRESS WILL EVENTUALLY BE CONNECTED TO A GLOVE BOX LINE. (9/29/69) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

  3. Glacial isostatic adjustment and Holocene to contemporary source-to-sink fluxes in valley-fjord systems in western Norway

    NASA Astrophysics Data System (ADS)

    Beylich, Achim A.; Laute, Katja; Liermann, Susan

    2013-04-01

    The focus of this Norwegian Research Council (NFR) funded Norwegian Individual Project (http://www.ngu.no/sedymont) within the European Science Foundation (ESF) SedyMONT (as part of EUROCORES TOPO-EUROPE) Programme (http://www.esf.org/topoeurope) is on Holocene, subrecent and contemporary sedimentary fluxes and budgets in selected valley-fjord systems (Erdalen and Bødalen) in Nordfjord, western Norway. The following main aims can be pointed out: - Analyse in which way glacial isostatic adjustment and surface denudational processes have been interacting over the Holocene - Analyse how the inheritance of the landscape due to the influence of the Last Glacial Maximum (LGM) has affected surface process rates over time - Document changes in surface process rates over different timescales by combining knowledge on Holocene surface process rates with data on subrecent and contemporary surface process rates High-resolution monitoring of denudational surface processes in the Erdalen and Bødalen drainage basin systems, in combination with repeated analyses of surface water chemistry, atmospheric solute inputs and granulometric as well as shape analyses of suspended sediments provide high-resolution data to analyse and quantify present-day sedimentary and solute fluxes as well as sediment sources, denudation rates, and meteorological and topographical / landscape morphometric controls of denudational surface processes. In addition to standard methods for monitoring bedload transport, innovative techniques like impact sensors and biofilm analysis are applied in combination with advanced flume experiments (for calibration of field data) to analyse channel stability / mobility and to estimate bedload transport rates in both drainage basin systems. Lakes are functioning as significant sediment traps within both drainage basins and the volume and composition of lake sediments are studied using echo-sounder, georadar and different coring techniques. Investigations on volumes and

  4. Comparison of ceramic waste forms produced by hot uniaxial pressing and by cold pressing and sintering

    SciTech Connect

    Oversby, V.M.; Vance, E.R.

    1994-09-01

    Synroc C waste form specimens prepared using the Australian-developed technology are uniaxially pressed in stainless steel bellows at 1200{degrees}C and 20MPa. This produces a material with high chemical and physical durability and with the radioactivity enclosed inside both the waste form and the bellows. An alternative method of producing the ceramic product is to use cold pressing of pellets followed by reactive sintering to provide densification and mineralization. Depending on the scale of waste form preparation required and on the activity level and nature of the waste streams, the cold press and sinter method may have advantages. To evaluate the effects of production method on waste form characteristics, especially resistance to dissolution or leaching of waste elements, we have prepared two simulated waste samples for evaluation. Both samples were prepared from liquid precursor materials (alkoxides, nitrates, and colloidal silica) and then doped with waste elements. The precursor material in each case corresponded to a basic phase assemblage of 60% zirconolite, 15% nepheline, 10% spinel, 10% perovskite, and 5% rutile. One sample was doped with 25% by weight of U; the other with 10% by weight each of U and Gd. Each sample was calcined at 750{degrees}C for 1 hr. in a 3.5% H{sub 2} in N{sub 2} atmosphere. Then one portion of each sample was hot pressed at temperatures ranging from 1120 to 1250{degrees}C and 20MPa pressure in steel bellows. A separate portion of each sample was formed into pellets, cold pressed, and sintered in various atmospheres at 1200{degrees}C to produce final products about 2/3 cm in diameter. Samples were then examined to determine density of the product, grain sizes of the phases, phase assemblage, and the location of the U and Gd in the final phases. Density data indicate that sintering gives good results provided that the samples are held at 200{degrees}C for long enough to allow trapped gases to escape.

  5. Model of the western Laurentide Ice Sheet from glacio-isostatic adjustment analysis and revised margin locations

    NASA Astrophysics Data System (ADS)

    Gowan, E. J.; Tregoning, P.; Purcell, A.

    2013-12-01

    Uncertainties in ice sheet extent and thickness during the retreat of the western Laurentide Ice Sheet from the last glacial maximum affect estimates of its contribution to global climate and sea level change during the late Pleistocene and early Holocene. These difficulties arise due to a lack of chronological constraints on the timing of margin retreat in many areas and a lack of observations of the glacio-isostatic deformation due the ice sheet. We present a model of the western Laurentide ice sheet in North America based on new ice margin reconstructions and well dated glacial lake strandlines. The model of the Laurentide ice sheet is constructed based on the assumption of perfectly plastic, steady state conditions with temporally variable basal shear stress and margin location. Initial models of basal shear stress were based on modern surficial geology and geography, and adjusted in an iterative process to reflect the volume of ice needed to fit observations of earth deformation caused by the ice sheet. The ice margins were developed by determining the minimum timing of retreat and using that as a constraint on the absolute maximum possible ice margin location. By using the ice margin as the starting point of modelling, assumptions on the location of ice domes and saddles were avoided. Initial results of the modelling indicate that ice thickness remained below 1500 m throughout the Western Canadian Sedimentary Basin region at the last glacial maximum as a result of low basal shear stress. Modelled flow direction matches geomorphic ice flow indicators lending confidence to the glaciological model. Ice sheet margin retreat was limited until after 15,000 cal yr BP. The most significant ice volume losses happened after retreat from southern Alberta and after retreat began on the Canadian Shield.

  6. GIA modelling of the Hanish and Camarinal Sills to generate isostatic corrections for continuous sea level curves

    NASA Astrophysics Data System (ADS)

    Williams, Felicity; Tamisiea, Mark E.; Rohling, Eelco J.; Grant, Katharine M.

    2014-05-01

    Submarine sills are critical points that regulate the exchange flow between enclosed basins and the open ocean. Isostatic modelling of two sills is presented: The Hanish Sill, which regulates exchange between the Red Sea and the Indian Ocean, and the Camarinal Sill which performs a similar function between the Mediterranean Sea and the Atlantic Ocean. A 244 kyr ice history, based on the of the ICE-5G global ice model is used, and a spherically symmetrical, viscoelastic earth is parameterised over three lithospheric thicknesses and a range of upper and lower mantle viscosities. Though the sills are in geologically different settings, with one sill on the basin side, and one sill on the ocean side of the narrowest passage, the relative sea level response is strikingly similar. We determine that in each case, while the offset between relative and global mean sea level is not constant over time, it roughly scales proportionally with land-ice variations such that an estimation of global mean sea level, and thus global ice volume, can be recovered from continuous sea level curves generated at these sills. The relationship between global mean sea level (ESL) and relative sea level (RSL) at the Camarinal Sill can be expressed as ESL=1.23(±0.08)RSL +0.5(±1.9) with errors expressed at two standard deviations. The Hanish Sill response, which displays greater sensitivity to duration of interglacial, is better characterised by two equations which describe an envelope of possible behaviour dependent on phase of glaciation (ESL=1.13RSL +8.5) or deglaciation (ESL=1.24RSL -9.0).

  7. Modeling of planetesimal compaction by hot pressing

    NASA Astrophysics Data System (ADS)

    Neumann, W.; Breuer, D.; Spohn, T.

    2014-07-01

    Compaction of initially porous material prior to melting is an important process that has influenced the interior structure and the thermal evolution of planetesimals in their early history. On one hand, compaction decreases the porosity resulting in a reduction of the radius. On the other hand, the loss of porosity results in an increase of the thermal conductivity of the material and, thus, in a more efficient cooling. Porosity loss by hot pressing is the most efficient process of compaction in planetesimals and can be described by creep flow, which depends on temperature and stress. Hot pressing has been repeatedly modeled using a simplified approach, for which the porosity is gradually reduced in some fixed temperature interval between ~650 K and 700 K [see e.g. 1--3]. This approach neglects the dependence of compaction on stress. In the present study [see 4], we compare this ''parametrized'' method with a self-consistent calculation of porosity loss via a ''creep-related'' approach. We use our thermal evolution model from previous studies [5] to model compaction of an initially porous ordinary chondritic body and consider four basic packings of spherical dust grains (simple cubic, orthorhombic, rhombohedral, and body-centered cubic). Depending on the grain packing, we calculate the effective stress and the associated porosity change via the thermally activated creep flow. For comparison, compaction is also modeled by simply reducing the initial porosity linearly to zero between 650 and 700 K. Since we are interested in thermal metamorphism and not melting, we only consider bodies that experience a maximum temperature below the solidus temperature of the metal phase. For the creep related approach, the temperature interval in which compaction takes place depends strongly on the size of the planetesimal and is not fixed as assumed in the parametrized approach. Depending on the radius, the initial grain size, the activation energy, the initial porosity, and the

  8. Parallelization of Rocket Engine Simulator Software (PRESS)

    NASA Technical Reports Server (NTRS)

    Cezzar, Ruknet

    1997-01-01

    Parallelization of Rocket Engine System Software (PRESS) project is part of a collaborative effort with Southern University at Baton Rouge (SUBR), University of West Florida (UWF), and Jackson State University (JSU). The second-year funding, which supports two graduate students enrolled in our new Master's program in Computer Science at Hampton University and the principal investigator, have been obtained for the period from October 19, 1996 through October 18, 1997. The key part of the interim report was new directions for the second year funding. This came about from discussions during Rocket Engine Numeric Simulator (RENS) project meeting in Pensacola on January 17-18, 1997. At that time, a software agreement between Hampton University and NASA Lewis Research Center had already been concluded. That agreement concerns off-NASA-site experimentation with PUMPDES/TURBDES software. Before this agreement, during the first year of the project, another large-scale FORTRAN-based software, Two-Dimensional Kinetics (TDK), was being used for translation to an object-oriented language and parallelization experiments. However, that package proved to be too complex and lacking sufficient documentation for effective translation effort to the object-oriented C + + source code. The focus, this time with better documented and more manageable PUMPDES/TURBDES package, was still on translation to C + + with design improvements. At the RENS Meeting, however, the new impetus for the RENS projects in general, and PRESS in particular, has shifted in two important ways. One was closer alignment with the work on Numerical Propulsion System Simulator (NPSS) through cooperation and collaboration with LERC ACLU organization. The other was to see whether and how NASA's various rocket design software can be run over local and intra nets without any radical efforts for redesign and translation into object-oriented source code. There were also suggestions that the Fortran based code be

  9. Lifting shoeprints using gelatin lifters and a hydraulic press.

    PubMed

    Shor, Yaron; Tsach, Tsadok; Vinokurov, Asya; Glattstein, Baruch; Landau, Eliezer; Levin, Nadav

    2003-03-01

    A method for lifting two-dimensional dust footwear marks on rough or porous surfaces, such as cardboard or cloth, using a hydraulic press, was examined. It was found that exerting pressure on the lifter by the press usually improves the quality of the results. When the shoeprints were on rough or soft surfaces, the prints transferred to the gelatin lifters were better than those obtained by the conventional method. In other cases, using the press did not improve the results but was much simpler to apply. Based on the results of this study, the hydraulic press/gelatin lifter method (the "press method") is used at the authors' laboratory, depending on the surface from which the shoeprint is to be lifted. It is the authors' intention to apply the method to other surfaces after finding the optimal pressure for surfaces with loose fibers. PMID:12664996

  10. Speed-invariant, on-press color quality measurements

    SciTech Connect

    Simpson, M.L.; Bliss, R.F.; McMillan, D.E.; Nodine, R.N.; Goddard, J.S.

    1991-12-03

    Color measurement is an important aspect of quality control for graphic printing press operation. Normally, measurements of color quality are performed by sampling the product off-line, in which case feedback to press operators is not available in a timely manner. On-press measurement of color quality provides timely feedback to the press operators; however, maintaining the accuracy of the measurement in a dynamic setting is not trivial. In this paper, a colorimeter measurement system using commercially available equipment is described for making reliable, on-press color measurements. The system was demonstrated on a web test bed running loops of printed graphic images. Examples of commercially printed graphic material include product labels, packaging, stamps, and wall paper. Resulting color measurements were shown to be highly sensitive to variations in color-content while maintaining invariance to web speeds as high as 500 ft/min. 6 refs.

  11. STS-46 post flight press conference

    NASA Astrophysics Data System (ADS)

    1992-08-01

    At a post flight press conference, the flight crew of the STS-46 mission (Cmdr. Loren Shriver, Pilot Andrew Allen, Mission Specialists Claude Nicollier (European Space Agency (ESA)), Marsha Ivins (Flight Engineer), Jeff Hoffman (Payload Commander), Franklin Chang-Dias, and Payload Specialist Franco Malerba (Italian Space Agency (ISA))) discussed their roles in and presented video footage, slides and still photographs of the different aspects of their mission. The primary objectives of the mission were the deployment of ESA's European Retrievable Carrier (EURECA) satellite and the joint NASA/ISA deployment and testing of the Tethered Satellite System (TSS). Secondary objectives included the IMAX Camera, the Limited Duration Space Environment Candidate Materials Exposure (LDVE), and the Pituitary Growth Hormone Cell Function (PHCF) experiments. Video footage of the EURECA and TSS deployment procedures are shown. Earth views were extensive and included Javanese volcanoes, Amazon basin forest ground fires, southern Mexico, southern Bolivian volcanoes, south-west Sudan and the Sahara Desert, and Melville Island, Australia. Questions from reporters and journalists from Johnson Space Center and Kennedy Space Center were discussed.

  12. [Work disability in public press professions].

    PubMed

    Akermann, S

    2002-09-01

    In this study more than 1,000 cases of long-term disability among members of the press and media were evaluated. Mental disorders were the main cause of disability in almost every fourth case. In women psychiatric illnesses were even more important. The most common diagnosis was that of a depressive disorder which accounted for more than half of all psychiatric cases. The causes of disability of other insurance systems such as the German social security scheme and the pension and disability plan for the medical profession were compared. Mental illnesses are the leading cause of disability in white collar workers and orthopaedic illnesses, especially disorders of the vertebral column, are the leading cause in blue collar workers, as one might have expected. In females mental disorders are even more common than in men whereas men tend to have more cardiovascular problems than women. In this study also some interesting features regarding disability caused by various illnesses after long-term follow-up were found. This opens unknown perspectives allowing new assessment of diseases and eventually will enable the actuary to price medical diagnoses for disability insurance. PMID:12242775

  13. STS-114: Discovery Post MMT Press Conference

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Bruce Buckingham of NASA Public Affairs hosted this press conference. Wayne Hill, Space Shuttle Deputy Program Manager; John Muratore, Shuttle Systems and Integration Manager; Mike Wetmore, Director for Shuttle Processing were present. Wayne started with a video from Shuttle Logistics Depot showing details of a point sensor box commonly named the black box. Work with the trouble shooting continues on a day to day basis, no definite launching date is set. John reports that they are in a mission support mode all over the country until the sensor problem is solved. Mike reports his team will complete scrub and securing tasks through the next day, restore the facility to its normal mode, and will start to a four day process of getting back to launch once trouble shooting is completed. Tanking test, thermal environment, problem identification, engine cut-off sensor problems, sensors, risk, design reviews, test and analysis, correlation of the problem with Columbia, are some of the topics covered with the News media.

  14. [Gender and health in the daily press].

    PubMed

    Revuelta, Gemma; Alonso, Inma; Tomás, Sonia; Guerrero, Marcela; Rohlfs, Izabella

    2004-05-01

    To have a better understanding on the role of the press in the communication of gender and health issues, the content of the five most spread newspapers in Spain was studied (El País, ABC, El Mundo, La Vanguardia and El Periódico de Catalunya) for five years (1997-2001) and the electronic version of The New York Times of the period 1990-1999. An unequal distribution was observed in the responsibility as for the information related to three aspects: positions of responsibility in the newspapers (out of 71 main posts, 67 were men and 4 women); the authors of the articles on health issues (61.2% men and 38,8% women, among the articles that include the author) and the mentioned information sources (81.43% men and 17.77% women). Among the 120 health issues that were covered during the period of the study, only 20 explicitly mentioned a woman (16.67%). Those subjects that included more frequently explicit references were: ablation, iatrogenics, sterilization, sexual and reproductive health, incontinence, beauty and domestic violence. The analysis of the approach to these subjects helped to identify the stereotypes of gender inequality, in the language as well as in the approach. PMID:15171880

  15. The Watchdog in Nineteenth Century Libel Law: A Common Law Concept of Freedom of the Press.

    ERIC Educational Resources Information Center

    Gleason, Timothy W.

    In press law, the individual right of freedom of the press frequently is linked to a public interest or "watchdog" concept of freedom of the press. This concept suggests that the basis for the constitutional protection of press freedom is the role of the press as an institution serving a collective good, as opposed to the traditional view of…

  16. Steel, corrosion resistant, bars, and wire, and forgings 17Cr 0.52Mo (0.95 - 1.20c) powder metallurgy product, host isostatically pressed. (SAE standard)

    SciTech Connect

    1996-08-01

    These products have been used typically for parts requiring minimum hardness of 58 HRC and resistance to wear, corrosion, and oxidation, but usage is not limited to such applications. UNS Number: S4400.

  17. Astronomy Press Releases: What We Choose To Share

    NASA Astrophysics Data System (ADS)

    Gay, Pamela L.

    2009-01-01

    Everyday, astronomy departments and facilities around the world issue press releases via the AAS Press Release service. These stories are selected for a variety of reasons that often (but do not always) include: the significance of a discover, public appeal, it is a first/last/largest/smallest discovery, and something historic has occurred (for instance, launch of a space craft). What astronomers as a field select to communicate to the public via press releases shapes public understanding of astronomy.In this poster, 6 months of press releases sent via email from the AAS Press Release service are examined to see how astronomy was communicated from January 1, 2008 through June 30, 2008. Press Releases are classified by topic using Astrophysical Journal keywords to look for trends, and the words used in the titles are studied to see what words press officers and scientists are using to communicate and to entice content providers into reporting their stories. Additionally, the first 100 discrete discoveries are examined to see which releases have more coverage within the blogisphere and trends in what is and is not covered are examined.

  18. Pressing effect in polymer solar cells with bulk heterojunction nanolayers.

    PubMed

    Park, Jiho; Nam, Sungho; Kim, Hwajeong; Kim, Youngkyoo

    2011-01-01

    We report the effect of pressing light-absorbing layers on the performance of polymer solar cells. The light-absorbing active layer was prepared on the transparent conducting oxide coated substrates from solutions that contain a mixture of regioregular poly(3-hexylthiophene) and soluble fullerene molecules. The active layers were pressed using a home-built micro-press system by controlling temperature and pressure, followed by the top electrode deposition. The surface of the active layers pressed was examined using atomic force microscope, while the photovoltaic characteristics of devices were measured under simulated solar light illumination (air mass 1.5 G, 100 mW/cm2). Results showed that the dark current of devices was noticeably increased by pressing the active layer without respect to the pressing temperature. The highest power conversion efficiency was achieved for the device with the active layer pressed under 10 kgf at 70 degrees C. The result was explained in terms of surface morphology and thermophysical effect. PMID:21446447

  19. Zinc coated sheet steel for press hardening

    NASA Astrophysics Data System (ADS)

    Ghanbari, Zahra N.

    Galvanized steels are of interest to enhance corrosion resistance of press-hardened steels, but concerns related to liquid metal embrittlement have been raised. The objective of this study was to assess the soak time and temperature conditions relevant to the hot-stamping process during which Zn penetration did or did not occur in galvanized 22MnB5 press-hardening steel. A GleebleRTM 3500 was used to heat treat samples using hold times and temperatures similar to those used in industrial hot-stamping. Deformation at both elevated temperature and room temperature were conducted to assess the coating and substrate behavior related to forming (at high temperature) and service (at room temperature). The extent of alloying between the coating and substrate was assessed on undeformed samples heat treated under similar conditions to the deformed samples. The coating transitioned from an α + Gamma1 composition to an α (bcc Fe-Zn) phase with increased soak time. This transition likely corresponded to a decrease in availability of Zn-rich liquid in the coating during elevated temperature deformation. Penetration of Zn into the substrate sheet in the undeformed condition was not observed for any of the processing conditions examined. The number and depth of cracks in the coating and substrate steel was also measured in the hot-ductility samples. The number of cracks appeared to increase, while the depth of cracks appeared to decrease, with increasing soak time and increasing soak temperature. The crack depth appeared to be minimized in the sample soaked at the highest soak temperature (900 °C) for intermediate and extended soak times (300 s or 600 s). Zn penetration into the substrate steel was observed in the hot-ductility samples soaked at each hold temperature for the shortest soak time (10 s) before being deformed at elevated temperature. Reduction of area and elongation measurements showed that the coated sample soaked at the highest temperature and longest soak time

  20. Multiproxy assessment of Holocene relative sea-level changes in the western Mediterranean: sea-level variability and improvements in the definition of the isostatic signal

    NASA Astrophysics Data System (ADS)

    Vacchi, Matteo; Rovere, Alessio; Marriner, Nick; Morhange, Christophe; Spada, Giorgio; Fontana, Alessandro

    2016-04-01

    After the review of 918 radiocarbon dated Relative Sea-Level (RSL) data-points we present here the first quality-controlled database constraining the Holocene sea-level histories of the western Mediterranean Sea (Spain, France, Italy, Slovenia, Croatia, Malta and Tunisia). We reviewed and standardized the geological RSL data-points using a new multi-proxy methodology based on: (1) modern taxa assemblages in Mediterranean lagoons and marshes; (2) beachrock characteristics (cement fabric and chemistry, sedimentary structures); and (3) the modern distribution of Mediterranean fixed biological indicators. These RSL data-points were coupled with the large number of archaeological RSL indicators available for the western Mediterranean. We assessed the spatial variability of RSL histories for 22 regions and compared these with the ICE-5G VM2 GIA model. In the western Mediterranean, RSL rose continuously for the whole Holocene with a sudden slowdown at ~7.5 ka BP and a further deceleration during the last ~4.0 ka BP, after which time observed RSL changes are mainly related to variability in isostatic adjustment. The sole exception is southern Tunisia, where data show evidence of a mid-Holocene high-stand compatible with the isostatic impacts of the melting history of the remote Antarctic ice sheet. Our results indicate that late-Holocene sea-level rise was significantly slower than the current one. First estimates of GIA contribution indicate that, at least in the northwestern sector, it accounts at least for the 25-30% of the ongoing sea-level rise recorded by Mediterranean tidal gauges. Such contribution is less constrained at lower latitudes due to the lower quality of the late Holocene index points. Future applications of spatio-temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of Mediterranean sea-level rise.

  1. Deep-burial diagenesis: Its implications for vertical movements of the crust, uplift of the lithosphere and isostatic unroofing—A review

    NASA Astrophysics Data System (ADS)

    Friedman, Gerald M.

    1987-03-01

    Various techniques of study of strata exposed at the surface in undeformed areas of the Appalachian Basin and Ozark Done, imply that these strata have been heated to temperatures that suggest a former great depth of burial. The data reveal that the strata have been much more deeply buried than previously thought. If such former deep burial has taken place, then subsequent uplift and erosion must also have taken place to bring these formerly deeply buried strata to the present land surface. Unexpectedly large amounts of uplift and erosion, ranging from 4.3 to 7 km, have re-exposed these formerly deeply buried rocks. This leads to the surprising conclusion that isostatic unroofing has stripped off thick sections of strata whose presence was previously unsuspected. Therefore, the lithosphere, in its isostatic unroofing of thick sequences of sedimentary strata, has undergone much larger vertical motions than many geologists had previously estimated. Case histories in this review include strata of the Silurian of the Northern Appalachian Basin and of the Ordovician of the Ozark Dome, which reached interpreted maximum burial depths of 5 and 4.3 km, respectively; Devonian strata in the Catskill Mountains of New York imply a former depth of burial of ˜ 6.5 km. Lower Ordovician carbonate sequences of the Northern Appalachian Basin imply a depth of burial in excess of 7 km; Middle Ordovician strata from the same basin signify a depth of burial of approximately 5 km; and Devonian strata, a paleodepth of 4.5-5 km. Such former great depths of burial of undeformed strata, which are now exposed at the surface, reflect large-scale vertical movements of the crust and uplift of the lithosphere. These drastic changes represent isostatic unroofing with widespread implications for paleogeography of a kind unrecognized at present.

  2. 57. ORIGINAL TILE PRESS AND EXPERIMENTAL DENTAL KILN, SECOND FLOOR, ...

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

    57. ORIGINAL TILE PRESS AND EXPERIMENTAL DENTAL KILN, SECOND FLOOR, NORTH WING, HENRY MERCER USED THE KILN FOR HIS EARLIEST GLAZE TESTS. THE PRESS WAS DESIGNED TO BE USED WITH METAL CASED MOLDS. SINCE ONLY THE EARLIEST TILE DESIGNS ARE IN METAL CASES. THIS TECHNIQUE WAS PROBABLY DISCONTINUED. THIS PRESS WAS, THEREFORE, PROBABLY NOT USED EXTENSIVELY AT THIS SITE. THE UPPER PART OF GLAZE KILN No. 2 IS AT THE LEFT REAR. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  3. Digital Isostatic Gravity Map of the Nevada Test Site and Vicinity, Nye, Lincoln, and Clark Counties, Nevada, and Inyo County, California

    USGS Publications Warehouse

    Ponce, David A.; Mankinen, E.A.; Davidson, J.G.; Morin, R.L.; Blakely, R.J.

    2000-01-01

    An isostatic gravity map of the Nevada Test Site area was prepared from publicly available gravity data (Ponce, 1997) and from gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1999; Morin and Blakely, 1999). Gravity data were processed using standard gravity data reduction techniques. Southwest Nevada is characterized by gravity anomalies that reflect the distribution of pre-Cenozoic carbonate rocks, thick sequences of volcanic rocks, and thick alluvial basins. In addition, regional gravity data reveal the presence of linear features that reflect large-scale faults whereas detailed gravity data can indicate the presence of smaller-scale faults.

  4. Holocene sea-level changes along the North Carolina Coastline and their implications for glacial isostatic adjustment models

    USGS Publications Warehouse

    Horton, B.P.; Peltier, W.R.; Culver, S.J.; Drummond, R.; Engelhart, S.E.; Kemp, A.C.; Mallinson, D.; Thieler, E.R.; Riggs, S.R.; Ames, D.V.; Thomson, K.H.

    2009-01-01

    We have synthesized new and existing relative sea-level (RSL) data to produce a quality-controlled, spatially comprehensive database from the North Carolina coastline. The RSL database consists of 54 sea-level index points that are quantitatively related to an appropriate tide level and assigned an error estimate, and a further 33 limiting dates that confine the maximum and minimum elevations of RSL. The temporal distribution of the index points is very uneven with only five index points older than 4000 cal a BP, but the form of the Holocene sea-level trend is constrained by both terrestrial and marine limiting dates. The data illustrate RSL rapidly rising during the early and mid Holocene from an observed elevation of -35.7 ?? 1.1 m MSL at 11062-10576 cal a BP to -4.2 m ?? 0.4 m MSL at 4240-3592 cal a BP. We restricted comparisons between observations and predictions from the ICE-5G(VM2) with rotational feedback Glacial Isostatic Adjustment (GIA) model to the Late Holocene RSL (last 4000 cal a BP) because of the wealth of sea-level data during this time interval. The ICE-5G(VM2) model predicts significant spatial variations in RSL across North Carolina, thus we subdivided the observations into two regions. The model forecasts an increase in the rate of sea-level rise in Region 1 (Albemarle, Currituck, Roanoke, Croatan, and northern Pamlico sounds) compared to Region 2 (southern Pamlico, Core and Bogue sounds, and farther south to Wilmington). The observations show Late Holocene sea-level rising at 1.14 ?? 0.03 mm year-1 and 0.82 ?? 0.02 mm year-1 in Regions 1 and 2, respectively. The ICE-5G(VM2) predictions capture the general temporal trend of the observations, although there is an apparent misfit for index points older than 2000 cal a BP. It is presently unknown whether these misfits are caused by possible tectonic uplift associated with the mid-Carolina Platform High or a flaw in the GIA model. A comparison of local tide gauge data with the Late Holocene RSL

  5. Simple models for late Holocene and present-day Patagonian glacier fluctuations and predictions of a geodetically detectable isostatic response

    NASA Astrophysics Data System (ADS)

    Ivins, Erik R.; James, Thomas S.

    1999-09-01

    The late Holocene glacial moraine chronology in the southernmost South American Andes includes four ^1 ^4 C dated Neoglacial advances and retreats. These are used as proxy information to characterize mass fluctuation of the Patagonian icefields during the last 5000 years. Modelled ice loads force a phase-lagged viscoelastic gravitational deformation of the solid Earth. The ancient glacier fluctuations may, therefore, drive present-day crustal motion even in the absence of present-day ice mass imbalance. Numerical models show that such rates of present-day uplift and subsidence are larger than those driven by the viscous memory of late Pleistocene deglaciation. Both spherical and flat-earth models are employed, the latter being used to study exhaustively the effects of glacial load history on the predicted vertical crustal velocity. Recent assessment of net mass balance from 1944 to 1985 indicates that the Southern Patagonian icefield has significantly deteriorated due to snout retreat and thinning. Volume loss rates are estimated at about 3.4-9.3 km^3 yr^- ^1 . The predicted vertical isostatic response to this recession and to the modelled Holocene Neoglaciations is at a marginally detectable level (~1 mm yr^- ^1 ) if the mantle/asthenosphere beneath Patagonia has a viscosity of about 10^2 ^1 Pa s. However, for reduced mantle viscosities, the younger Holocene glacial load histories predict larger signatures. In fact, if the viscosity is about 2x10^2 ^0 Pa s, or lower, then geodetically detectable vertical motion may be driven by a regional Little Ice Age (LIA) (1400-1750 AD) glacier advance and subsequent 20th century retreat. Although this value for mantle viscosity is lower than thought typical of continental shield mantle (~10^2 ^1 Pa s), it is consistent with inversions for post-seismic relaxation time constants in island arc environments and in regions with significant Neogene continental tectonism. In the viscosity regime of 5x10^1 ^8 -2x10^1 ^9 Pa s, the

  6. Pyrometry in the Multianvil Press: New approach for temperature measurement in large volume press experiments

    NASA Astrophysics Data System (ADS)

    Sanehira, T.; Wang, Y.; Prakapenka, V.; Rivers, M. L.

    2008-12-01

    Temperature measurement in large volume press experiments has been based on thermocouple emf, which has well known problems: unknown pressure dependence of emf [e.g., 1], chemical reaction between thermocouple and other materials, deformation related texture development in the thermocouple wires [2], and so on. Thus, different techniques to measure temperatures in large volume press experiments other than thermocouples are required to measure accurate temperatures under high pressures. Here we report a new development using pyrometry in the multianvil press, where temperatures are derived on the basis of spectral radiometry. Several high pressure runs were conducted using the 1000 ton press with a DIA module installed at 13 ID-D GSECARS beamline at Advanced Photon Source (APS) [3]. The cubic pressure medium, 14 mm edge length, was made of soft-fired pyrophyllite with a graphite furnace. A moissanite (SiC) single crystal was built inside the pressure medium as a window for the thermal emission signal to go through. An MgO disk with 1.0 mm thickness was inserted in a gap between the top of the SiC crystal and thermocouple hot junction. The bottom of the window crystal was in direct contact with the tip of the anvil, which had a 1.5 mm diameter hole drilled all the way through the anvil axis. An optical fiber was inserted in this hole and the open end of fiber was in contact with the SiC crystal. Thermal spectral radiance from the inner cell assembly was obtained via the fiber and recorded by an Ocean Optics HP2000 spectrometer. The system response of spectrometer was calibrated by a tungsten ribbon ramp (OL550S, Optronic Laboratories, Inc.) with standard of spectral radiance. The cell assembly was compressed up to target value of 15 tons and then temperature was increased up to 1573 K. Radiation spectra were mainly obtained above 873 K and typical integration time was 1 ms or 10 ms. Data collection was done in the process of increase and decrease of temperature. In

  7. VIEW WEST, 1ST FLOOR, EAST ROOM, HYDRAULIC COTTON PRESS, DETAIL, ...

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

    VIEW WEST, 1ST FLOOR, EAST ROOM, HYDRAULIC COTTON PRESS, DETAIL, CONTINENTAL GIN COMPANY HYDRAULIC TANK - Magnolia Plantation, Cotton Gins & Presses, LA Route 119, Natchitoches, Natchitoches Parish, LA

  8. Renovation of the hot press in the Plutonium Experimental Facility

    SciTech Connect

    Congdon, J.W.; Nelson, G.H.

    1990-03-05

    The Plutonium Experimental Facility (PEF) will be used to develop a new fuel pellet fabrication process and to evaluate equipment upgrades. The facility was used from 1978 until 1982 to optimize the parameters for fuel pellet production using a process which was developed at Los Alamos National Laboratory. The PEF was shutdown and essentially abandoned until mid-1987 when the facility renovations were initiated by the Actinide Technology Section (ATS) of SRL. A major portion of the renovation work was related to the restart of the hot press system. This report describes the renovations and modifications which were required to restart the PEF hot press. The primary purpose of documenting this work is to help provide a basis for Separations to determine the best method of renovating the hot press in the Plutonium Fuel Fabrication (PuFF) facility. This report also includes several SRL recommendations concerning the renovation and modification of the PuFF hot press. 4 refs.

  9. 41. Detail of punch press on left and large metal ...

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

    41. Detail of punch press on left and large metal plate shear, Boiler Shop, located in north end of Machine Shop Building. - Thames Tow Boat Company, Foot of Farnsworth Street, New London, New London County, CT

  10. Rugged pressed disk electrode has low contact potential

    NASA Technical Reports Server (NTRS)

    Day, J. L.; Mosier, B.

    1965-01-01

    Pressed-disk electrode with low contact potential monitors physiological processes. It consists of silver and silver chloride combined with bentonitic clay. The clay affords a surface that permits use over extended periods without contact deterioration.

  11. VIEW OF INTERIOR SPACE WITH HUFFORD BULLDOZIER FORMING PRESS IN ...

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

    VIEW OF INTERIOR SPACE WITH HUFFORD BULLDOZIER FORMING PRESS IN FOREGROUND, FACING NORTHWEST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  12. VIEW OF INTERIOR SPACE WITH SQUARE SHAPE STRETCH PRESS CONTAINMENT ...

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

    VIEW OF INTERIOR SPACE WITH SQUARE SHAPE STRETCH PRESS CONTAINMENT PITS CENTER, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  13. VIEW OF INTERIOR SPACE WITH RECTANGULAR SHAPE STRETCH PRESS CONTAINMENT ...

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

    VIEW OF INTERIOR SPACE WITH RECTANGULAR SHAPE STRETCH PRESS CONTAINMENT PIT IN BACKGROUND, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  14. 5. FOURTH FLOOR, HOTEL SOAP LINES TO NORTHWEST: PRESS (LEFT ...

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

    5. FOURTH FLOOR, HOTEL SOAP LINES TO NORTHWEST: PRESS (LEFT CENTER), MANUAL CUTTERS (CENTER, RIGHT CENTER) - Colgate & Company Jersey City Plant, Building No. B-15, 90-96 Greene Street, Jersey City, Hudson County, NJ

  15. 8. Second floor front apartment showing ornately painted pressed metal ...

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

    8. Second floor front apartment showing ornately painted pressed metal ceiling, as well as modern partitions and wall treatments. View looking north. - Franklin Grocery Company Building, 1 South Main Street, Franklin, Merrimack County, NH

  16. 13. RADIAL DRILL, ENGINE LATHE, DRILL PRESS, AND GRINDER (L ...

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

    13. RADIAL DRILL, ENGINE LATHE, DRILL PRESS, AND GRINDER (L TO R)-LOOKING SOUTHEAST. - W. A. Young & Sons Foundry & Machine Shop, On Water Street along Monongahela River, Rices Landing, Greene County, PA

  17. INTERIOR VIEW WITH CARLTON RADIAL ARM DRILL PRESS (THE CARLTON ...

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

    INTERIOR VIEW WITH CARLTON RADIAL ARM DRILL PRESS (THE CARLTON MACHINE TOOL CO., CINCINNATI, OHIO) WITH MACHINE OPERATOR, EDDIE BURTTRAM. - O'Neal Steel, Incorporated, Fabrication Shop, 744 Forty-first Avenue North, Birmingham, Jefferson County, AL

  18. 20. VIEW OF WATSON STILHMAN DISMOUNTING WHEEL PRESS. 600 tons. ...

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

    20. VIEW OF WATSON STILHMAN DISMOUNTING WHEEL PRESS. 600 tons. Gary Stich, operator. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  19. Study of pressing machine pressure relief characteristics based on AMESim

    NASA Astrophysics Data System (ADS)

    Wang, Chuanli; Zhang, Hui; Yu, Caofeng; Wu, Xiaolei

    2016-01-01

    When a working cylinder of the pressing machine working cylinder was stuck and underwent retracted conversion, pressure shock was high in working cylinder cavity and flow pulsation was distinct in the pipeline due to the high working pressure and frequent retracted transformation of the working cylinder, which not only shortened the service life of the pressing machine, but also exerted serious impacts on the machining precision and quality, especially after the pressing machine applied loads and high-pressure oil in work rod end cavity of working cylinder needed to be relieved in a short time. In order to research and analyze the better pressure relief characteristics of the two types of pressure relief circuits of the pressing machine, the paper established models, carried out simulation and analysis and then made contrastive analysis of the working cylinder rod velocity, rod acceleration and port pressure pulsation according to the simulation results.

  20. AUTOMOTIVE REPAIR SHOP, DETAIL OF FABRICATING PRESS IN EAST END ...

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

    AUTOMOTIVE REPAIR SHOP, DETAIL OF FABRICATING PRESS IN EAST END OF MAIN WING, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  1. 55. QUARRY TILE CUTTERS, SECOND FLOOR, NORTH WING. WORKERS PRESSED ...

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

    55. QUARRY TILE CUTTERS, SECOND FLOOR, NORTH WING. WORKERS PRESSED THE CUTTERS INTO SLABS OF CLAY, LIFTED THEM ONTO DRYING BOARDS AND PRESSED THE PLUNGERS TO RELEASE THE CUT TILES. REPRODUCTIONS CUTTERS ARE NOT USED IN PRODUCTION. WOODEN FORMS FOR PRODUCING CLAY SLABS WITH ROLLING PINS REST AGAINST THE WALL. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  2. VIEW OF THE INSTALLATION OF AN EXTRUSION PRESS IN THE ...

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

    VIEW OF THE INSTALLATION OF AN EXTRUSION PRESS IN THE HIGH BAY AREA OF BUILDING 865. THE EXTRUSION PRESS WAS USED TO PRODUCE CYLINDRICAL BARS, HOLLOW TUBES, AND SHAPES WITH IRREGULAR CROSS-SECTIONS BY FORCING PREHEATED METAL THROUGH A DIE ORIFICE UNDER HIGH PRESSURE. (5/22/70) - Rocky Flats Plant, Metal Research & Development Laboratory, South of Central Avenue at south end of terminus of Ninth Avenue, Golden, Jefferson County, CO

  3. Gemini 10 prime crew during post flight press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    At podium during Gemini 10 press conference are (l-r) Dr. Robert C. Seamans, Astronauts John Young and Michael Collins and Dr. Robert R. Gilruth (39895); Wide angle view of the Manned Spacecraft Center (MSC) News Center during the Gemini 10 prime crew post flight press conference (38786); Astronaut Young draws diagram on chalk board of tethered extravehicular activity accomplished during Gemini 10 flight (39897).

  4. Low-loss binder for hot pressing boron nitride

    DOEpatents

    Maya, Leon

    1991-01-01

    Borazine derivatives used as low-loss binders and precursors for making ceramic boron nitride structures. The derivative forms the same composition as the boron nitride starting material, thereby filling the voids with the same boron nitride material upon forming and hot pressing. The derivatives have a further advantage of being low in carbon thus resulting in less volatile byproduct that can result in bubble formation during pressing.

  5. Grain refinement of aluminum using equal-channel angular pressing

    SciTech Connect

    Horita, Z.; Furukawa, M.; Nemoto, M.; Langdon, T.G.

    2000-07-01

    Using the technique of equal-channel angular (ECA) pressing, it is possible to reduce the grain size of polycrystalline materials to the submicrometer level. Thus, this processing technique has the potential for producing materials which may exhibit superplasticity. This paper describes various factors affecting the development and evolution of the microstructure produced by ECA pressing. Optimization of such factors is then presented for the advent of superplasticity.

  6. Bending strength studies on hot-pressed silicon carbide

    NASA Technical Reports Server (NTRS)

    Kriegesmann, J.

    1984-01-01

    The 4-point bending strength of 4 grades of hot-pressed SiC was determined at different temperatures. With a transgranular mode of fracture the values for bending strength are retained up to high temperatures. For intergranular fracture the decrease of strength is governed by subcritical crack growth. The intergranular fracture is caused by a high content of silicate glassy phase at the grain boundaries of hot-pressed SiC.

  7. Binderless briquetting of coals and biomass in roll press

    SciTech Connect

    Komarek, R.K.

    1996-12-31

    An analysis of the stresses in compacted materials was employed to investigate methods which can improve briquettability of coal and biomass in roll press. The special roll face design, four roll press, as well as special hot briquetting installation were tested. Experimental results are given for several different briquetted materials. In the last section of the paper, the advantages of this process as well as possibilities for commercial application are discussed.

  8. Glacial isostatic adjustment in response to changing Late Holocene behaviour of ice streams on the Siple Coast, West Antarctica

    NASA Astrophysics Data System (ADS)

    Nield, Grace A.; Whitehouse, Pippa L.; King, Matt A.; Clarke, Peter J.

    2016-04-01

    The Siple Coast region of Antarctica contains a number of fast-flowing ice streams, which control the dynamics and mass balance of the region. These ice streams are known to undergo stagnation and reactivation cycles, which lead to ice thickness changes that may be sufficient to excite a viscous solid Earth response (glacial isostatic adjustment; GIA). This study aims to quantify Siple Coast ice thickness changes during the last 2000 yr in order to determine the degree to which they might contribute to GIA and associated present-day bedrock uplift rates. This is important because accurate modelling of GIA is necessary to determine the rate of present-day ice-mass change from satellite gravimetry. Recently-published reconstructions of ice-stream variability were used to create a suite of kinematic models for the stagnation-related thickening of Kamb Ice Stream since ˜1850 AD, and a GIA model was used to predict present-day deformation rates in response to this thickening. A number of longer-term loading scenarios, which include the stagnation and reactivation of ice streams across the Siple Coast over the past 2000 yr, were also constructed, and used to investigate the longer term GIA signal in the region. Uplift rates for each of the ice loading histories, based on a range of earth models, were compared with regional GPS-observed uplift rates and an empirical GIA estimate. We estimate Kamb Ice Stream to have thickened by 70-130 m since stagnation ˜165 years ago. Modelled present-day vertical motion in response to this load increase peaks at -17 mm yr-1 (i.e. 17 mm yr-1 subsidence) for the weakest earth models tested here. Comparison of the solid Earth response to ice load changes throughout the last glacial cycle, including ice stream stagnation and reactivation across the Siple Coast during the last 2000 yr, with an empirical GIA estimate suggests that the upper mantle viscosity of the region is greater than 1 × 1020 Pa s. When upper mantle viscosity values of

  9. The forward and adjoint sensitivity methods of glacial isostatic adjustment: Existence, uniqueness and time-differencing scheme

    NASA Astrophysics Data System (ADS)

    Martinec, Zdenek; Sasgen, Ingo; Velimsky, Jakub

    2014-05-01

    In this study, two new methods for computing the sensitivity of the glacial isostatic adjustment (GIA) forward solution with respect to the Earth's mantle viscosity are presented: the forward sensitivity method (FSM) and the adjoint sensitivity method (ASM). These advanced formal methods are based on the time-domain,spectral-finite element method for modelling the GIA response of laterally heterogeneous earth models developed by Martinec (2000). There are many similarities between the forward method and the FSM and ASM for a general physical system. However, in the case of GIA, there are also important differences between the forward and sensitivity methods. The analysis carried out in this study results in the following findings. First, the forward method of GIA is unconditionally solvable, regardless of whether or not a combined ice and ocean-water load contains the first-degree spherical harmonics. This is also the case for the FSM, however, the ASM must in addition be supplemented by nine conditions on the misfit between the given GIA-related data and the forward model predictions to guarantee the existence of a solution. This constrains the definition of data least-squares misfit. Second, the forward method of GIA implements an ocean load as a free boundary-value function over an ocean area with a free geometry. That is, an ocean load and the shape of ocean, the so-called ocean function, are being sought, in addition to deformation and gravity-increment fields, by solving the forward method. The FSM and ASM also apply the adjoint ocean load as a free boundary-value function, but instead over an ocean area with the fixed geometry given by the ocean function determined by the forward method. In other words, a boundary-value problem for the forward method of GIA is free with respect to determining (i) the boundary-value data over an ocean area and (ii) the ocean function itself, while the boundary-value problems for the FSM and ASM are free only with respect to

  10. 22 CFR 9b.1 - Press access to the Department of State.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Press access to the Department of State. 9b.1 Section 9b.1 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS GOVERNING DEPARTMENT OF STATE PRESS BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid Department of State press building...

  11. An Update of Freedom of the Press and Information in Latin America and the Caribbean.

    ERIC Educational Resources Information Center

    Garrison, Bruce; Munoz, Julio E.

    This paper is based on a review of the literature that included reports from the Inter-American Press Association's general assembly in Los Angeles in October 1984, the mid-year meeting of the Inter-American Press Association in Panama City in March 1985, and the 1983 world press freedom review of the International Press Institute. Other material…

  12. 22 CFR 9b.1 - Press access to the Department of State.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Press access to the Department of State. 9b.1 Section 9b.1 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS GOVERNING DEPARTMENT OF STATE PRESS BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid Department of State press building...

  13. 22 CFR 9b.1 - Press access to the Department of State.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Press access to the Department of State. 9b.1 Section 9b.1 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS GOVERNING DEPARTMENT OF STATE PRESS BUILDING PASSES § 9b.1 Press access to the Department of State. (a) Media correspondents without valid Department of State press building...

  14. A Study on the Specifications of Cold Pressed Colza Oil.

    PubMed

    Yazdani-Nasab, Zahra; Piravi-Vanak, Zahra

    2015-01-01

    Cold pressed oil extraction is the preferred method for seeds with high contents of oil, such as colza. Generally speaking, expeller pressing is less complex, more cost efficient and safer than solvent extraction. Moreover, cold pressed oils retain their natural properties better. Cold pressed colza oil has been found to have numerous health benefits. This was an original and unique study conducted as part of the research for the international Codex standard for cold pressed fats and oils, and aims to examine the chemical properties of two varieties of Iranian colza seed, Hyola and Okapi. The studied factors included (a) chemical properties, and (b) physicochemical and quality characteristics. Based on our findings, both varieties of colza seeds in this study had satisfactory levels of oleic and linoleic acid, and no trans-fatty acids. Although both samples had good nutritional properties, the Hyola variety was higher in oleic acid, indicating better oxidative stability. Due to the considerable amounts of β-sitosterol in both varieties, they may be effective in reducing cholesterol and preventing cancer. PMID:26043928

  15. Bilberry and bilberry press cake as sources of dietary fibre

    PubMed Central

    Aura, Anna-Marja; Holopainen-Mantila, Ulla; Sibakov, Juhani; Kössö, Tuija; Mokkila, Mirja; Kaisa, Poutanen

    2015-01-01

    Background Dietary recommendations for Nordic countries urge the use of plant foods as a basis for healthy nutrition. Currently, the level of dietary fibre (DF) intake is not adequate. Berries are an elementary part of the recommended Nordic healthy diet and could be consumed in higher amounts. Materials and methods Finnish bilberries and a bilberry press cake from juice processing were studied for DF content, carbohydrate composition, and non-carbohydrate fibre content, which was analysed as sulphuric acid insoluble and soluble material. The microstructure of all samples was also studied using light microscopy and toluidine blue O, calcofluor, and acid fuchsin staining. Results The total DF contents of fresh and freeze-dried bilberries and the press cake were 3.0, 24.1, and 58.9%, respectively. Most of the DF was insoluble. Only about half of it was carbohydrate, the rest being mostly sulphuric acid–insoluble material, waxy cutin from skins, and resilient seeds. Bilberry seeds represented over half of the press cake fraction, and in addition to skin, they were the major DF sources. Microscopy revealed that skins in the press cake were intact and the surface of the seeds had thick-walled cells. Conclusions Bilberry press cake is thus a good source of insoluble non-carbohydrate DF, and could be used to provide DF-rich foods to contribute to versatile intake of DF. PMID:26652738

  16. Quality parameters for cold pressed edible argan oils.

    PubMed

    Matthäus, Bertrand

    2013-01-01

    Argan oil belongs to the high-price vegetable oils on the market. Therefore, consumers have the right to purchase a high-quality product. The quality of edible vegetable oils is defined in food standards in which sensory quality is the most important feature. Additional parameters are defined to assess the identity of oils or to evaluate their oxidative state. The sensory quality of cold pressed argan oil is altered if the production has not been performed with reasonable care regarding raw material and extraction. Only oil from roasted seeds extracted by a screw-press had a sufficient sensory quality over a period of 20 weeks without unacceptable sensory attributes. Under accelerated storage conditions oil from roasted seeds extracted by a screw-press remained below the limits given by the Codex Alimentarius or the German guideline for Edible Fats and Oils for peroxide and totox value. Oil from unroasted seeds or oil from goat-digested roasted seeds and extracted by a screw-press, as well as oil from roasted seeds traditionally extracted, exceeded these limits. Initial oxidative stability of oil from unroasted seeds was significantly lower than that of the other oils. After 35 days under accelerated storage, oil from roasted seeds obtained using a screw-press showed the highest oxidative stability. Moreover, tocopherol and phytosterol compositions are useful features of argan oil. PMID:23472455

  17. Paleogeography and paleoenvironments of southwestern Baffin Island (Nunavut, Canada): post-glacial isostatic uplift and isolation of Nettilling Lake from marine influence

    NASA Astrophysics Data System (ADS)

    Narancic, Biljana; Pienitz, Reinhard; Francus, Pierre; Guilbault, Jean-Pierre

    2014-05-01

    Although signs of recent climate change are more compelling in circumpolar regions, we have limited knowledge of Arctic climates and environments and their past variability. In order to better understand and anticipate the extent and nature of future changes in the Arctic, it is necessary to increase our capacity to model past environmental changes. Instrumental monitoring using high technology in circumpolar regions has been implemented only over recent decades. Hence, to extend the climate record in time, we use a multi-proxy paleolimnological approach to study the sedimentary records preserved in Nettilling Lake, the largest lake in the Canadian Arctic Archipelago. The main objective is to reconstruct the postglacial environmental history of the Nettilling Lake watershed using biological and geochemical proxies. Nettilling Lake, Baffin Island, has a surface area of 5,541 km2 and a maximum depth of 65 m. Its basin has undergone postglacial marine invasion following the last deglaciation due to isostatic subsidence exerted by the Laurentide Ice Sheet. The glacio-isostatic uplift of the region resulted in the establishment of a freshwater lake between ca. 6000-6500 B.P. as established by radiocarbon dating. Biostratigraphic and geochemical analyses were completed on two sediment cores, one from a lagoonal system in the northwestern part and another from the eastern part of the Lake. The sediment records clearly document the marine-lacustrine transition through paleosalinity shifts inferred from the chemistry of the cores, and the composition of fossil diatom and foraminifer assemblages. Remains of fossil chironomid larvae first appeared in the record after basin isolation and the establishment of freshwater conditions. Precise radiocarbon dating of the isolation contacts helps refine regional glacio-isostatic rebound and the duration and extent of the postglacial marine phase. Post-glacial marine regression and the associated changes in paleosalinity are also

  18. Solutions to Challenges Facing a University Digital Library and Press

    PubMed Central

    D'Alessandro, Michael P.; Galvin, Jeffrey R.; Colbert, Stephana I.; D'Alessandro, Donna M.; Choi, Teresa A.; Aker, Brian D.; Carlson, William S.; Pelzer, Gay D.

    2000-01-01

    During the creation of a university digital library and press intended to serve as a medical reference and education tool for health care providers and their patients, six distinct and complex digital publishing challenges were encountered. Over nine years, through a multidisciplinary approach, solutions were devised to the challenges of digital content ownership, management, mirroring, translation, interactions with users, and archiving. The result is a unique, author-owned, internationally mirrored, university digital library and press that serves as an authoritative medical reference and education tool for users around the world. The purpose of this paper is to share the valuable digital publishing lessons learned and outline the challenges facing university digital libraries and presses. PMID:10833161

  19. Natural Hazards and the press in the western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Llasat-Botija, M.; Llasat, M. C.; López, L.

    2007-07-01

    This study analyses press articles published between 1982 and 2005 in an attempt to describe the social perception of natural hazards in Catalonia. The articles included in the database have been classified according to different types of risk. In addition, the study examines the evolution of each type of risk in the press coverage during the study period. Finally, the results have been compared to data provided by insurance companies with respect to compensations paid out for damages. Conclusions show that floods are the most important natural hazard in the region, but that the number of headlines for each event is greater in the case of snowfalls and forest fires. Factors such as the season of the year, the proximity of the affected region to the capital, the topical issues at the time, and the presence of other important news must be considered when the impact in the press is analysed.

  20. Method for hot pressing irregularly shaped refractory articles

    DOEpatents

    Steinkamp, William E.; Ballard, Ambrose H.

    1982-01-01

    The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

  1. Crack toughness evaluation of hot pressed and forged beryllium

    NASA Technical Reports Server (NTRS)

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

    1971-01-01

    Beryllium fracture toughness test specimens were fatigue cracked using reversed cycling with a compression load two to three times the tension load. In worked beryllium, textures may be produced which result in fatigue cracks that are out of plane with the starter notch. Specimens of hot pressed stock exhibited load displacement records which were nonlinear throughout their course. Fracture specimens of both hot pressed and forged stock showed essentially no reduction of thickness and the fracture surfaces were flat and normal to the load axis. However, the stress intensity factor at maximum load increased with decreasing thickness. Load-displacement and electric potential records for the hot pressed beryllium specimens exhibited several anomalies such as negative residual crack mouth displacements and a decrease in electrical potential with increasing load.

  2. Thermal conductance of pressed contacts at liquid helium temperatures

    NASA Technical Reports Server (NTRS)

    Salerno, L. J.; Kittel, P.; Spivak, A. L.

    1983-01-01

    It is pointed out that the optimum design of cryogenic instruments requires accurate thermal models. The present models are limited by a lack of knowledge of the low temperature thermal conductance of the bolted joints which are typically used in the instrument-to-system interface. In connection with studies of pressed contacts, it has been found that the thermal conductance does not obey the Wiedemann-Franz law. The present investigation is concerned with the characterization of the thermal conductance of pressed contacts at liquid helium-4 temperatures, taking into account the dependence of thermal contact conductance on applied force and temperature. It is shown that for the 0.4 micron OFHC copper pressed contact pair, the thermal conductance varies roughly as the second power of the temperature, and increases with increasing applied force.

  3. New applications of roller presses in coal-related technologies

    SciTech Connect

    Pietsch, W.; Guenter, H.

    1993-12-31

    The roller press was invented around the middle of the 19th century. Its objective was to develop an economic method for the agglomeration of coal fines. The first successfully operating machine was constructed by the Belgian Louiseau and was installed in a US coal briquetting plant in the late 1870s; therefore this type of equipment was later also referred to as {open_quotes}Belgian Press{close_quotes}. Until the middle of this century many manufacturers produced roller presses and a large number of plants was built, particularly in Europe, to produce mostly egg-shaped briquettes from hard coal fines with coal tar pitch or bitumen as a binder. These briquettes were used as fuel for home and industrial heating. After other, cleaner sources of energy, such as gas, oil, and electricity, became affordable, coal briquetting lost its importance. A small number of almost historic plants is still operating but construction of new ones is scarce. Only a few manufacturers of roller presses are still offering such equipment, mostly for other applications. Recently, a renewed interest in roller presses has developed in connection with innovative coal technologies. These include: Briquetting of non-coking coal for the generation of {open_quotes}form-coke{close_quotes}; production of smoke-less coal briquettes; briquetting of coal for gasification or liquefication techniques; size enlargement by briquetting of fine, upgraded coals, e.g. dried sub-bituminous coal or products from advanced coal cleaning processes, to improve their transport and handling properties; agglomeration of by-products from flue gas desulfurization; and, last but not least, briquetting of coal ashes to allow disposal or beneficial use. In the following such new applications of roller presses for coal related technologies will be reviewed and features of modern machines which are required for their successful operations will be described.

  4. Accuracy of press reports on gamma-ray astronomy

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.; Nemiroff, Robert J.; Hurley, Kevin

    2000-09-01

    Most Americans learn about modern science from press reports, while such articles have a bad reputation among scientists. We have performed a study of 148 news articles on gamma-ray astronomy to quantitatively answer the questions ``How accurate are press reports of gamma-ray astronomy?'' and ``What fraction of the basic claims in the press are correct?'' We have taken all articles on the topic from five news sources (UPI, New York Times, Sky & Telescope, Science News, and five middle-sized city newspapers) for one decade (1987-1996) We found an average rate of roughly one trivial error every two articles, while none of our 148 articles significantly mislead the reader or misrepresented the science. This quantitative result is in stark contrast to the nearly universal opinion among scientists that the press frequently butchers science stories. So a major result from our study is that reporters should be rehabilitated into the good graces of astrophysicists, since they actually are doing a good job. For our second question, we rated each story with the probability that its basic new science claim is correct. We found that the average probability over all stories is 70%. Since the reporters and the scientists are both doing good jobs, then why is 30% of the science you read in the press wrong? The reason is that the nature of news reporting is to present front-line science and the nature of front-line science is that reliable conclusions have not yet been reached. The combination of these two natures forces fast breaking science news to have frequent incorrect ideas that are subsequently identified and corrected. So a second major result from our study is to make the distinction between textbook science (with reliabilities near 100%) and front-line science which you read about in the press (with reliabilities near 70%). .

  5. Process design of press hardening with gradient material property influence

    SciTech Connect

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-04

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  6. Process design of press hardening with gradient material property influence

    NASA Astrophysics Data System (ADS)

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-01

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  7. New technique of machining high precision mirror surface press roller

    NASA Astrophysics Data System (ADS)

    Hongsen, Deng

    1991-03-01

    High precision mirror surface press roller machining technique of corrosion and grinding proof is one of the key techniques that the production enterprises as well as the machining and manufacturing of the following industries sought to resolve for a long time: plastics, papermaking, rubber, film, and chip production. In Oct. 1984, a new comprehensive machining technique of metal brush coating, grinding with abrasive belt, as well as buffing was used to conduct nearly 20 experiments. In Jan. 1985, a pair of middle convex high precision mirror surface press rollers was successfully machined. The technical process is described.

  8. Properties of Hot Pressed Titanium Alloy Powders for Cryogenic Applications.

    NASA Technical Reports Server (NTRS)

    Friedman, G. I.; Kazaroff, J. M.

    1970-01-01

    Evaluation of strength and toughness of hot-pressed titanium alloy powders at room and at cryogenic temperatures. The purpose was to determine how the mechanical properties of solid bodies formed from powder would compare with wrought specimens of the same size and with the same chemical analysis. It was found that of five titanium powder-making processes investigated, only the Rotating Electrode Process (REP) was capable of producing ELI-grade titanium alloy powder. Blocks hot-pressed from spherical REP powders had tensile properties equivalent to or better than those obtained from wrought bar.

  9. 25. Paper ready for the calender presses. This picture shows ...

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

    25. Paper ready for the calender presses. This picture shows the paper after it has been coated and dried, as shown on page 238, and it being rolled at the end of the coating-machine. It is now ready to be sent to the big presses which calender it (or iron it, as popular pariance would have it). The pictures on pages 238 and 239 show a continuous process over a single machine; but on account of the length of teh machine, the process is illustrated in sections. (p.239.) - Champion-International Paper Company, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  10. Pressure-induced structural changes in the network-forming isostatic glass GeSe4: An investigation by neutron diffraction and first-principles molecular dynamics

    NASA Astrophysics Data System (ADS)

    Bouzid, Assil; Pizzey, Keiron J.; Zeidler, Anita; Ori, Guido; Boero, Mauro; Massobrio, Carlo; Klotz, Stefan; Fischer, Henry E.; Bull, Craig L.; Salmon, Philip S.

    2016-01-01

    The changes to the topological and chemical ordering in the network-forming isostatic glass GeSe4 are investigated at pressures up to ˜14.4 GPa by using a combination of neutron diffraction and first-principles molecular dynamics. The results show a network built from corner- and edge-sharing Ge(Se1 /2)4 tetrahedra, where linkages by Se2 dimers or longer Sen chains are prevalent. These linkages confer the network with a local flexibility that helps to retain the network connectivity at pressures up to ˜8 GPa, corresponding to a density increase of ˜37 % . The network reorganization at constant topology maintains a mean coordination number n ¯≃2.4 , the value expected from mean-field constraint-counting theory for a rigid stress-free network. Isostatic networks may therefore remain optimally constrained to avoid stress and retain their favorable glass-forming ability over a large density range. As the pressure is increased to around 13 GPa, corresponding to a density increase of ˜49 % , Ge(Se1 /2)4 tetrahedra remain as the predominant structural motifs, but there is an appearance of 5-fold coordinated Ge atoms and homopolar Ge-Ge bonds that accompany an increase in the fraction of 3-fold coordinated Se atoms. The band gap energy decreases with increasing pressure, and midgap states appear at pressures beyond ˜6.7 GPa. The latter originate from undercoordinated Se atoms that terminate broken Sen chains.

  11. The Press, the Government, and the Ethics Vacuum.

    ERIC Educational Resources Information Center

    Merrill, John C.

    Immanuel Kant's idea of a will to do the right thing--to be ethical--is essentially a dead concept with both press and government. The reasons for this "ethics vacuum" are two-fold: the foundations of ethics in both circles are vague, confusing, and beset by relativism and pragmatism so that no system of ethics ever really coalesces; and neither…

  12. The Press and California Higher Education. A Report.

    ERIC Educational Resources Information Center

    Chance, William

    This study examined the media coverage of California higher education in the popular press in four of the state's major dailies. In particular the study examined the roles that the San Francisco Chronicle, the Sacramento Bee, the Los Angeles Times, and the San Jose Mercury News play in fostering the public debate about higher education. All the…

  13. 42. PRESSING A SLAB OF CLAY ONTO A MOSAIC MOLD. ...

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

    42. PRESSING A SLAB OF CLAY ONTO A MOSAIC MOLD. THE MOLD, WHICH HAS A RAISED DESIGN, LEAVES AND OUTLINE IN THE SLAB, THE PIECES THUS DEFINED, ARE THEN CUT APART TO BE FIRED SEPARATELY AND REASSEMBLED. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  14. PRESS SITE BECOMES INTERNATIONAL GATHERING SITE FOR MEDIA

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The KSC press site becomes a busy international gathering site for the media during shuttle launch periods. Various activities are held in a number of facilities ranging in age. The news dome (shown during mission STS-41 pre-launch) was originally built as part of the 1976 Bicentennial.

  15. SOURCE ASSESSMENT: PRESSED AND BLOWN GLASS MANUFACTURING PLANTS

    EPA Science Inventory

    This report summarizes the results of a study to gather and analyze background information and technical data related to air emissions from glass manufacturers producing pressed and blown glassware. This includes all glassware except flat glass, glass containers, and fiber glass....

  16. The First Amendment, Schools and the Press: A Current Issue.

    ERIC Educational Resources Information Center

    Sasse, Mary

    While it is informative to trace the vicissitudes to which the First Amendment has been subjected since 1791, it is obvious that as far as schools are concerned, the courts have interpreted freedom of speech and the press in a limited way. For example, the courts have ruled that boards of education may remove books from school libraries on the…

  17. Argonne Director Eric Isaacs addresses the National Press Club

    ScienceCinema

    Eric Isaccs

    2010-01-08

    Argonne Director Eric Isaacs addresses the National Press Club on 9/15/2009. To build a national economy based on sustainable energy, the nation must first "reignite its innovation ecology," he said. Issacs makes the case for investing in science to secure America's future.

  18. The Press of the Soviet Union: A Bibliography.

    ERIC Educational Resources Information Center

    Bergethon, Bruce; And Others

    Compiled in response to the need for more information on the differences between the press systems of the United States and the Soviet Union, this bibliography contains 240 entries. Consisting of newspaper articles, journal articles, books, and pamphlets, the bibliography provides an overview of the different journalistic philosophies of the two…

  19. Quid Pro Quo: Tobacco Companies and the Black Press

    PubMed Central

    McCandless, Phyra M.; Yerger, Valerie B.

    2012-01-01

    Objectives. We explored the relationship between tobacco companies and the Black press, which plays an important role in conveying information and opinions to Black communities. Methods. In this archival case study, we analyzed data from internal tobacco industry documents and archives of the National Newspaper Publishers Association (NNPA), the trade association of the Black press. Results. In exchange for advertising dollars and other support, the tobacco industry expected and received support from Black newspapers for tobacco industry policy positions. Beginning in the 1990s, resistance from within the Black community and reduced advertising budgets created counterpressures. The tobacco industry, however, continued to sustain NNPA support. Conclusions. The quid pro quo between tobacco companies and the Black press violated journalistic standards and represented an unequal trade. Although numerous factors explain today's tobacco-related health disparities, the Black press's service to tobacco companies is problematic because of the trust that the community placed in such media. Understanding the relationship between the tobacco industry and the NNPA provides insight into strategies that the tobacco industry may use in other communities and countries. PMID:21852652

  20. DETAIL VIEW OF FILTER PRESS REMAINS, BOILER, SECONDARY ORE BIN, ...

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

    DETAIL VIEW OF FILTER PRESS REMAINS, BOILER, SECONDARY ORE BIN, TRAM TRESTLE AND WATER TANK, LOOKING NORTHWEST. HIS VIEW IS TAKEN FROM THE THIRD LEVEL OF THE MILL, NEARBY THE BLACKSMITH'S FORGE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  1. 19. Interior detail, grinder and drill press, Machine Shop, Roundhouse ...

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

    19. Interior detail, grinder and drill press, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to south (135mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

  2. 18. Interior detail, drill press and grinder, Machine Shop, Roundhouse ...

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

    18. Interior detail, drill press and grinder, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to east (135mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

  3. Tell Us More: Reading Comprehension, Engagement, and Conceptual Press Discourse

    ERIC Educational Resources Information Center

    McElhone, Dot

    2012-01-01

    This study examines interactions between teachers and students during reading comprehension instruction to determine how certain patterns of teacher-student talk support student comprehension achievement and reading engagement. The central focus of the study is "conceptual press discourse," a pattern of teacher response that includes requests for…

  4. Looking north at uing press of the submerged arc weld ...

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

    Looking north at u-ing press of the submerged arc weld (saw) line of the main pipe mill building, bay 7. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

  5. 9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES ...

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

    9. VIEW OF MOLTEN SALT BATH EQUIPMENT AND ROLLER PRESSES BEING INSTALLED ON THE WEST SIDE (SIDE B) OF BUILDING 883. SIDE B OF BUILDING 883 WAS USED TO PROCESS ENRICHED URANIUM FROM 1957-66. (1/23/57) - Rocky Flats Plant, Uranium Rolling & Forming Operations, Southeast section of plant, southeast quadrant of intersection of Central Avenue & Eighth Street, Golden, Jefferson County, CO

  6. Ethics and the Press: Readings in Mass Media Morality.

    ERIC Educational Resources Information Center

    Merrill, John C., Ed.; Barney, Ralph D., Ed.

    This collection of 35 articles addresses the topic of the ethical considerations and implications involved in reporting the news. Included in this book are such articles as: "Ethics and Journalism" by John Merrill, "Quality in Mass Communications" by Wilbur Schramm, "The American Press: Some Truths About Truths" by Edward Jay Epstein, "The New…

  7. Googling "Deaf": Deafness in the World's English-Language Press

    ERIC Educational Resources Information Center

    Power, Des

    2007-01-01

    An Internet search tool, Google Alert, was used to survey the global English-language press July-December 2005 for references to deaf people. The survey found that such references focus on people who are deaf rather than the disability itself, thus demonstrating how well deaf people fit into the mainstream. Derogatory terminology such as "deaf and…

  8. University Press Meeting Dominated by Donor Proposal and Digital Publishing

    ERIC Educational Resources Information Center

    Howard, Jennifer

    2007-01-01

    A surprise request for proposals from the Andrew W. Mellon Foundation and a forthcoming report on university publishing in the digital age were among topics discussed at the annual meeting of the Association of American University Presses. The offer from the Mellon Foundation concerns support for collaborative, monograph-centered projects in…

  9. Student Press Freedom: One View of the "Hazelwood" Decision.

    ERIC Educational Resources Information Center

    Goodman, Mark

    1988-01-01

    Reviews the "Hazelwood v. Kuhlmeier" U.S. Supreme Court decision upholding a principal's right to censor the content of a school-sponsored student publication. Explains why teachers oppose this decision, discusses liability issues, and argues for a free, uncensored student press. Includes eight legal references. (MLH)

  10. The Post-Revolutionary Portuguese Press: New Faces, Old Problems.

    ERIC Educational Resources Information Center

    Agee, Warren K.; Traquina, Nelson

    The Portuguese press is now guaranteed free access to official sources of information, professional confidentiality, freedom of publication and of competition, and the independence of the professional journalist; yet its ability to influence public opinion is limited by a traditional expectation of governmental repression and by present financial…

  11. A Community College District/University Press Copublishing Venture.

    ERIC Educational Resources Information Center

    Caraway, Georgia Kemp

    1994-01-01

    Describes cooperation between the Dallas County Community College District (DCCCD) and University of North Texas Press, resulting in the publication of a collection of short stories and a book of poetry written by DCCCD faculty and staff. Provides information on sales, marketing and promotion, classroom use of the books, and opportunities for…

  12. "...Establish the Student Press--And Stifle It!"

    ERIC Educational Resources Information Center

    McCallie, Franklin

    1990-01-01

    Presents an acceptance speech by Franklin McCallie, principal of Kirkwood High School (Missouri), for the "Administrator of the Year" award presented by the Missouri Interscholastic Press Association and the Missouri Journalism Education Association in April 1989. Discusses journalism's role in achieving the school's chief goals: student growth,…

  13. Toward a Normative Theory of Freedom of the Press.

    ERIC Educational Resources Information Center

    Jensen, Dwight Wm.

    In considering the possibility of a normative theory of freedom of the press, this paper examines arguments about such freedom in the Third World and elsewhere. Some of the arguments discussed in the paper are derived from the theories of John Locke and Karl Marx; others are drawn from the concepts of divine rights, elitism, liberal democracy, and…

  14. Extraction of proteins from pennycress seeds and press cake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to more fully utilize pennycress, a potentially viable bio-diesel source, the proteinaceous components were extracted from pennycress seed and press cake. The amino acid composition of the proteins present in pennycress was typical for proteins derived from plants, with glycine, glutamic ac...

  15. The CAPRI Project: Coordinates for Astronomical Press Release Images

    NASA Astrophysics Data System (ADS)

    Frattare, Lisa M.; Ferguson, B. A.; Summers, F.; Levay, Z. G.

    2009-01-01

    The beauty and splendor of astronomical press release images has made an enormously positive impact with the media and public alike. As a leading provider of astronomical imagery and a major contributor of Hubble Space Telescope press release images, the outreach division of Space Telescope Science Institute (STScI) recognizes the importance of making press release images compliant with virtual observatory standards for inclusion in databases and repositories. Our goal is to make outreach images accessible by virtual observatory applications by calculating World Coordinate System (WCS) data for these images. We provide updated and improved software that allows observatories to easily and accurately transform coordinates on their astronomical press release images, using reference FITS files. The resultant metadata conforms to the Simple Image Access (SIA) protocol established by the International Virtual Observatory Alliance and has been used by popular end users such as Google Sky and World Wide Telescope. Several hundred images from the STScI Office of Public Outreach NewsCenter database have been processed, and their coordinates and other relevant metadata are accessible through an SIA-compliant web service.

  16. Institutional Stress: Conflicting Normative Models in the Catholic Press.

    ERIC Educational Resources Information Center

    Thorn, William; Garrison, M. Bruce

    To determine whether the diocesan newspapers of the Catholic church are based on an autonomous, adversarial model or on an institutional, public relations model of the press, a survey was conducted of 148 editors and 145 bishops or publishers of such newspapers. Results showed that the editors and bishops agreed on the three major roles of the…

  17. Skylab 4 crewmen look over notes for press conference

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The three crewmen of the third manned Skylab mission look over their notes for their upcoming post-mission press conference at JSC. They are, from left to right, Astronaut Gerald P. Carr, commander; Scientist-Astronaut Edward G. Gibson, science pilot; and Astronaut William R. Pogue, pilot. The three astronauts spent 84 days aboard the Skylab space station cluster in Earth orbit.

  18. The Mutilated Boy and the Press: A Rumor Study.

    ERIC Educational Resources Information Center

    Brown, Lee

    Responsible editors avoid printing falsehoods, but the public sometimes demands that rumors be covered in the press. One example of such rumors and the way editors deal with them is the "Mutilated Boy." The "Mutilated Boy" rumor has been circulating for decades and involves a brutal attack upon a small boy in a public rest room. The "crime" is…

  19. Pressing for Elaboration in Student Talk about Texts

    ERIC Educational Resources Information Center

    McElhone, D.

    2013-01-01

    This article explores the practice of one accomplished teacher who uses follow-up probes to press her fourth- and fifth-grade students to clarify and articulate their ideas more fully. Qualitative analysis of field notes, teacher and student interviews, and video recordings of instruction, and discourse analysis of reading conferences revealed…

  20. Inter Press Service: News from the Third World.

    ERIC Educational Resources Information Center

    Giffard, C. Anthony

    A content analysis was undertaken of the files for one month of the Rome-based Inter Press Service (IPS), an international news agency specializing in the news relating to the Third World. The data suggested that IPS is indeed providing a different kind of news service from that of the traditional news agencies. More than three-quarters of the…

  1. Argonne Director Eric Isaacs addresses the National Press Club

    SciTech Connect

    Eric Isaccs

    2009-09-17

    Argonne Director Eric Isaacs addresses the National Press Club on 9/15/2009. To build a national economy based on sustainable energy, the nation must first "reignite its innovation ecology," he said. Issacs makes the case for investing in science to secure America's future.

  2. Coverage of Jamaica in the U.S. and Canadian Press in 1976: A Study of Press Bias and Effect.

    ERIC Educational Resources Information Center

    Cuthbert, Marlene; Sparkes, Vernone

    In 1976, Jamaican government officals claimed that their island had received an especially negative press in the United States during 1975 and 1976 with serious consequences for the economy and tourist trade. This accusation was not made about Canadian coverage, with one major exception, and Canadian tourism to Jamaica increased during those years…

  3. Metonymie dans la presse ecrite: entre discours et langue (Metonymies in the Press: Between Discourse and Language).

    ERIC Educational Resources Information Center

    Lecolle, Michelle

    2001-01-01

    This paper describes certain metonymies that are often employed in the daily French press. In such metonymies, a human being or a set of individuals are referred to by means of the name of an institutional location (i.e., a capital city, a ministry in a western country, the name of a country). These metonymic patterns do not seem to be used by…

  4. Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

    SciTech Connect

    Sujit Banerjee

    2005-10-31

    Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 µm are principally responsible. Georgia-Pacific is considering green

  5. Sea level and shoreline reconstructions for the Red Sea: isostatic and tectonic considerations and implications for hominin migration out of Africa

    NASA Astrophysics Data System (ADS)

    Lambeck, Kurt; Purcell, Anthony; Flemming, Nicholas. C.; Vita-Finzi, Claudio; Alsharekh, Abdullah M.; Bailey, Geoffrey N.

    2011-12-01

    The history of sea level within the Red Sea basin impinges on several areas of research. For archaeology and prehistory, past sea levels of the southern sector define possible pathways of human dispersal out of Africa. For tectonics, the interglacial sea levels provide estimates of rates for vertical tectonics. For global sea level studies, the Red Sea sediments contain a significant record of changing water chemistry with implications on the mass exchange between oceans and ice sheets during glacial cycles. And, because of its geometry and location, the Red Sea provides a test laboratory for models of glacio-hydro-isostasy. The Red Sea margins contain incomplete records of sea level for the Late Holocene, for the Last Glacial Maximum, for the Last Interglacial and for earlier interglacials. These are usually interpreted in terms of tectonics and ocean volume changes but it is shown here that the glacio-hydro-isostatic process is an additional important component with characteristic spatial variability. Through an iterative analysis of the Holocene and interglacial evidence a separation of the tectonic, isostatic and eustatic contributions is possible and we present a predictive model for palaeo-shorelines and water depths for a time interval encompassing the period proposed for migrations of modern humans out of Africa. Principal conclusions include the following. (i) Late Holocene sea level signals evolve along the length of the Red Sea, with characteristic mid-Holocene highstands not developing in the central part. (ii) Last Interglacial sea level signals are also location dependent and, in the absence of tectonics, are not predicted to occur more than 1-2 m above present sea level. (iii) For both periods, Red Sea levels at 'expected far-field' elevations are not necessarily indicative of tectonic stability and the evidence points to a long-wavelength tectonic uplift component along both the African and Arabian northern and central sides of the Red Sea. (iv) The

  6. Understanding the strength of hot-pressed nanostructured powder compacts

    SciTech Connect

    Rawers, J.C.; Harlow, D.G.

    1999-02-01

    Attrition-milled nanostructured powders were hot pressed, and macroscopic properties of density, hardness, grain size, and strength were measured. No correlation was found between processing conditions (temperature and time) used in this study and compact properties, nor was a correlation found between the tensile (or failure) stress and density, hardness, or grain size. Variations of compact properties of unmilled powder were similar to that of milled powders. Tensile data were not well fitted to a Gaussian distribution but were well fitted to a two-parameter Weibull distribution. Thus, although the milled powder compacts had an average tensile strength greater than the unmilled powder compacts, all sample compositions fit a distribution with zero as a possible minimal stress level. Weibull analysis suggests that the tensile and compression strength is controlled by the presence of fine cracks, which may limit future engineering applications. Efforts to eliminate these cracks during hot pressing were unsuccessful.

  7. Quantitative analysis of inclusion distributions in hot pressed silicon carbide

    SciTech Connect

    Michael Paul Bakas

    2012-12-01

    ABSTRACT Depth of penetration measurements in hot pressed SiC have exhibited significant variability that may be influenced by microstructural defects. To obtain a better understanding regarding the role of microstructural defects under highly dynamic conditions; fragments of hot pressed SiC plates subjected to impact tests were examined. Two types of inclusion defects were identified, carbonaceous and an aluminum-iron-oxide phase. A disproportionate number of large inclusions were found on the rubble, indicating that the inclusion defects were a part of the fragmentation process. Distribution functions were plotted to compare the inclusion populations. Fragments from the superior performing sample had an inclusion population consisting of more numerous but smaller inclusions. One possible explanation for this result is that the superior sample withstood a greater stress before failure, causing a greater number of smaller inclusions to participate in fragmentation than in the weaker sample.

  8. Crack toughness evaluation of hot pressed and forged beryllium.

    NASA Technical Reports Server (NTRS)

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

    1973-01-01

    Fracture toughness tests at room temperature were made on three-point loaded beryllium bend specimens cut from hot pressed block and a forged disk. These specimens had plane proportions conforming to ASTM E 399 and covered a thickness range of from 1/32 to 1/2 in. Two sets of bend specimens were tested, one having fatigue cracks and the other 0.5 mil radius notches. One objective of the investigation was the development of techniques to produce fatigue cracks in accordance with the procedures specified in ASTM E 399. This objective was achieved for the hot pressed material. In plane cracks were not consistently produced in the specimens cut from forged stock.

  9. Follicular contact dermatitis due to coloured permanent-pressed sheets

    PubMed Central

    Panaccio, François; Montgomery, D. C.; Adam, J. E.

    1973-01-01

    A delayed hypersensitivity type of allergic contact dermatitis was observed following exposure to certain brands of 50% cotton, 50% polyester coloured permanent-pressed sheets produced by a particular manufacturer. The dermatitis presented as an extremely pruritic follicular eczema of the body and vesicular edema of the ears and face. Patch testing excluded formalin as the allergen but suggested permanent-pressing chemicals as a possibility. Several washings of the sheets did not prevent the development of the dermatitis. The removal of sheets did not immediately result in improvement: the condition could persist for up to eight weeks after their discontinuance. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5 PMID:4268628

  10. Main roll for an air press of a papermaking machine

    DOEpatents

    Beck, David A.

    2004-03-09

    A roll for use in an air press assembly of a papermaking machine has a pair of ends associated therewith. The roll includes a pair of edge portions with each edge portion extending to one of the pair of ends. Each edge portion has an edge surface portion composed of a first material, the first material having a first hardness. The roll further includes a middle portion located between the pair of edge portions, the middle portion having a middle surface portion composed of a second material. The second material has a second hardness, the second material being harder than the first material. The first material is preferably a soft, seal material which promotes reduced air leakage from the air press assembly.

  11. STS-121: Discovery Entry Flight Director Post Landing Press Conference

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Steve Stitch, STS-121 Entry Flight Director, and Wayne Hale, Space Shuttle Program is shown in this post landing press conference. Steve Stitch begins with discussing the following topics: 1) Weather at Kennedy Space Center; 2) Gap filler protrusion; 3) De-orbit burn; 4) Space Shuttle Landing; 5) Global Position Satellite System (GPSS) performance; and 6) Post-landing rain showers. Wayne Hale discusses external tank observations at launch and the goals that were obtained by this flight, which are to deliver 4000 pounds of scientific equipment, increase the crew members to three on the International Space Station (ISS), and repair the ISS. Questions from the press on lessons learned from the Auxiliary Power Unit (APU) leak, and flight readiness reviews are addressed.

  12. Hydro-isostatic deflection and tectonic tilting in the central Andes: Initial results of a GPS survey of Lake Minchin shorelines

    NASA Technical Reports Server (NTRS)

    Bills, Bruce G.; De Silva, Shanaka L.; Currey, Donald R.; Emenger, Robert S.; Lillquist, Karl D.; Donnellan, Andrea; Worden, Bruce

    1994-01-01

    Sufficiently large lake loads provide a means of probing rheological stratification of the crust and upper mantle. Lake Minchin was the largest of the late Pleistocene pluvial lakes in the central Andes. Prominent shorelines, which formed during temporary still-stands in the climatically driven lake level history, preserve records of lateral variations in subsequent net vertical motions. At its maximum extent the lake was 140 m deep and spanned 400 km N-S and 200 km E-R. The load of surficial water contained in Lake Minchin was sufficient to depress the crust and underlying mantle by 20-40 m, depending on the subjacent rheology. Any other differential vertical motions will also be recorded as departures from horizontality of the shorelines. We recently conducted a survey of shoreline elevations of Lake Minchin with the express intent of monitoring the hydro-isostatic deflection and tectonic tilting. Using real-time differential Global Positioning System (GPS), we measured topographic profiles across suites of shorelines at 15 widely separated locations throughout the basin. Horizontal and vertical accuracies attained are roughly 30 and 70 cm, respectively. Geomorphic evidence suggests that the highest shoreline was occupied only briefly (probably less than 200 years) and radiocarbon dates on gastropod shells found in association with the shore deposits constrain the age to roughly 17 kyr. The basin-side pattern of elevations of the highest shoreline is composed of two distinct signals: (27 +/- 1) m of hydro-isostatic deflection due to the lake load, and a planar tilt with east and north components of (6.8 +/- 0.4) 10(exp -5) and 9-5.3 +/- 0.3) 10(exp -5). This rate of tilting is too high to be plausibly attributed to steady tectonism, and presumably reflects some unresolved combination of tectonism plus the effects of oceanic and lacustrine loads on a laterally heterogeneous substrate. The history of lake level fluctuations is still inadequately known to allow

  13. A new Holocene relative sea-level curve for western Brittany (France): Insights on isostatic dynamics along the Atlantic coasts of north-western Europe

    NASA Astrophysics Data System (ADS)

    Goslin, Jérôme; Van Vliet Lanoë, Brigitte; Spada, Giorgio; Bradley, Sarah; Tarasov, Lev; Neill, Simon; Suanez, Serge

    2015-12-01

    This study presents new Relative Sea Level (RSL) data that were obtained in the Finistère region (Western tip of Brittany, France) and the implications those data have for the understanding of the isostatic dynamics across north-western Europe, and more specifically along the Atlantic and Channel coasts. New stratigraphic sequences were obtained and analyzed to derive 24 new Sea-level Index Points, in which 6 are basal. These new data considerably increase the knowledge we have of the RSL evolution along the coasts of Western Brittany since the last 8 kyr B.P. From this new dataset, RSL was estimated to rise continuously over the last 8 kyr with a major inflection at ca. 6 kyr cal. BP. Our results show large vertical discrepancies between the RSL records of Brittany and South-Western UK, with the latter plotting several meters below the new data. From this comparison we suggest that the two regions underwent a very different pattern and/or amplitude of subsidence during the last 8 kyr which has implications for the spatial and temporal pattern of the peripheral bulge of the European ice sheets. We compared our data against predictions from Glacio-Isostatic Adjustment models (GIA models). There are large misfits between RSL observations and the predictions of the global (ICE-5G (VM2a) - Peltier, 2004, GLAC1-b - Tarasov and Peltier, 2002; Tarasov et al., 2012, Briggs et al., 2014) and regional UK models ("BIIS" - Bradley et al., 2009; Bradley et al., 2011; "Kuchar"- Kuchar et al., 2012), which can't be resolved through significant changes to the deglaciation history and size of the British-Irish Ice sheet. Paleo-tidal modelling corrections indicate regional changes in the tidal ranges played a negligible role in the data-model misfits. Hence, we propose that the misfits are due to some combination of: (i) unaccounted mass-loss of far-field ice-sheets (Antarctic ice-Sheet or Laurentide Ice-Sheet), (ii) unresolved differences in the deglaciation history and size of

  14. Comparing a thermo-mechanical Weichselian Ice Sheet reconstruction to reconstructions based on the sea level equation: aspects of ice configurations and glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Schmidt, P.; Lund, B.; Näslund, J.-O.; Fastook, J.

    2014-05-01

    In this study we compare a recent reconstruction of the Weichselian Ice Sheet as simulated by the University of Maine ice sheet model (UMISM) to two reconstructions commonly used in glacial isostatic adjustment (GIA) modelling: ICE-5G and ANU (Australian National University, also known as RSES). The UMISM reconstruction is carried out on a regional scale based on thermo-mechanical modelling, whereas ANU and ICE-5G are global models based on the sea level equation. The three models of the Weichselian Ice Sheet are compared directly in terms of ice volume, extent and thickness, as well as in terms of predicted glacial isostatic adjustment in Fennoscandia. The three reconstructions display significant differences. Whereas UMISM and ANU includes phases of pronounced advance and retreat prior to the last glacial maximum (LGM), the thickness and areal extent of the ICE-5G ice sheet is more or less constant up until the LGM. During the post-LGM deglaciation phase ANU and ICE-5G melt relatively uniformly over the entire ice sheet in contrast to UMISM, which melts preferentially from the edges, thus reflecting the fundamental difference in the reconstruction scheme. We find that all three reconstructions fit the present-day uplift rates over Fennoscandia equally well, albeit with different optimal earth model parameters. Given identical earth models, ICE-5G predicts the fastest present-day uplift rates, and ANU the slowest. Moreover, only for ANU can a unique best-fit model be determined. For UMISM and ICE-5G there is a range of earth models that can reproduce the present-day uplift rates equally well. This is understood from the higher present-day uplift rates predicted by ICE-5G and UMISM, which result in bifurcations in the best-fit upper- and lower-mantle viscosities. We study the areal distributions of present-day residual surface velocities in Fennoscandia and show that all three reconstructions generally over-predict velocities in southwestern Fennoscandia and that

  15. Apollo 11 Facts Project [Prelaunch Press Conference/EVA Training

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A prelaunch press conference shows the crewmembers of Apollo 11, Commander Neil A. Armstrong, Lunar Module Pilot Edwin E. Aldrin, Jr., and Command Module Pilot Michael Collins, answering questions about their upcoming mission (this section has sound, the rest of the video is without sound). Footage is seen of the crew during training for the extravehicular activity portion of the mission and using the flight simulator.

  16. Mechanical and thermophysical properties of hot-pressed SYNROC B

    SciTech Connect

    Hoenig, C.L.; Newkirk, H.W.; Otto, R.A.; Brady, R.L.; Brown, A.E.; Ulrich, A.R.; Lum, R.C.

    1981-05-06

    The optimal SYNROC compositons for use with commercial waste are reviewed. Large amounts of powder (about 2.5 kg) were prepared by convention al ceramic operations to test the SYNROC concept on a processing scale. Samples, 15.2 cm in diameter, were hot pressed in graphite, and representative samples were cut for microstructural evaluations. Measured mechanical and thermophysical properties did not vary significantly as a function of sample location and were typical of titanate ceramic materials.

  17. Lesbis sustineo! Naiad press authors remember Barbara Grier.

    PubMed

    Cantrell, Jaime

    2014-01-01

    Drawing from semi-structured interviews with some of Naiad Press's most celebrated women, including Katherine V. Forrest, Barbara's supervising editor at Naiad from 1983-1993; Sheila Ortiz Taylor, author of what is considered by many to be the first lesbian novel with a Chicana heroine; and the incomparable Lee Lynch, this work aims to sustain an ongoing remembrance of Grier's life and work by encouraging memory exploration--a symphonic blending of the printed and spoken word. PMID:25298097

  18. Support Assembly for Composite Laminate Materials During Roll Press Processing

    NASA Technical Reports Server (NTRS)

    Catella, Luke A.

    2011-01-01

    A composite laminate material is supported during the roll press processing thereof by an assembly having: first and second perforated films disposed adjacent to first and second opposing surfaces of a mixture of uncured resin and fibers defining the composite laminate material, a gas permeable encasement surrounding the mixture and the first and second films, a gas impervious envelope sealed about the gas permeable encasement, and first and second rigid plates clamped about the gas impervious envelope.

  19. PREPARATION OF METAL POWDER COMPACTS PRIOR TO PRESSING

    DOEpatents

    Mansfield, H.

    1958-08-26

    A method of fabricating uranium by a powder metallurgical technique is described. It consists in introducing powdered uranium hydride into a receptacle shaped to coincide with the coatour of the die cavity and heating the hydride so that it decomposes to uranium metal. The metal particles cohere in the shapw of the receptacle and thereafter the prefurmed metal powder is pressed and sintered to obtain a dense compact.

  20. American ASTP prime crew participate in press conference

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The three members of the American ASTP prime crew participate in an Apollo Soyuz Test Project (ASTP) press conference conducted on May 14, 1975 in bldg 2 briefing room at JSC. They are, left to right, Donald K. Slayton, docking module pilot; Vance D. Brand, command module pilot; and Thomas P. Stafford, commander. The astronauts discussed with the news media their recent ASTP joint training session in the Soviet Union, and the crew's tour of the USSR's Baykonur launch complex in Kazakhstan.