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Sample records for isostatically pressed beryllium-aluminum-silver

  1. Age hardening in rapidly solidified and hot isostatically pressed beryllium-aluminum-silver alloys

    SciTech Connect

    Carter, D.H.; McGeorge, A.C.; Jacobson, L.A.; Stanek, P.W.

    1995-07-01

    Three different alloys of beryllium, aluminum and silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compositions were, by weight, 50% Be, 47.5% Al, 2.5% Ag, 50% Be, 47% Al, 3% Ag, and 50% Be, 46% Al, 4% Ag. Due to the low solubility of both aluminum and silver in beryllium, the silver was concentrated in the aluminum phase, which appeared to separate from the beryllium in the liquid phase. A fine, continuous composite beryllium-aluminum microstructure was formed, which did not significantly change after hot isostatically pressing at 550 C for one hour at 30,000 psi argon pressure. Samples of HIP material were solution treated at 550 C for one hour, followed by a water quench. Aging temperatures were 150, 175, 200 and 225 C for times ranging from one half hour to 65 hours. Hardness measurements were made using a diamond pyramid indenter with a load of 1 kg. Results indicate that peak hardness was reached in 36--40 hours at 175 C and 12--16 hours at 200 C aging temperature, relatively independent of alloy composition.

  2. Age hardening in beryllium-aluminum-silver alloys

    SciTech Connect

    Carter, D.H.; McGeorge, A.C.; Jacobson, L.A.; Stanek, P.W.

    1996-11-01

    Three different alloys of beryllium-aluminum-silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compositions were, by weight percent, Be-47.5Al-2.5Ag, Be-47Al-3Ag, and Be-46Al-4Ag. Due to the low solubility of both aluminum and silver in beryllium, the silver was concentrated in the aluminum phase, which separates from the beryllium in the liquid phase. A fine, continuous composite beryllium-aluminum microstructure was formed, which did not significantly change after hot isostatic pressing. Samples of hot isostatically pressed material were solution treated at 550 C for 1 h, followed by a water quench. Aging temperatures were 150, 175, 200, and 225 C for times ranging from half an hour to 65 h. Results indicate that peak hardness was reached in 36--40 h at 175 C and 12--16 h at 200 C aging temperature, relatively independent of alloy composition.

  3. Hot isostatic pressing: Conference proceedings

    SciTech Connect

    Froes, F.H.; Hebeisen, J.; Widmer, R.

    1996-12-31

    The International Conference on Hot Isostatic Pressing was held on May 20-22, 1996, in Andover, Massachusetts. This conference discussed the state-of-the-art of hot isostatic pressing (HIP) and competing compaction techniques. HIP allows complex cost-effective near net shapes to be produced from powder products, densification of castings thereby enhancing performance, retention of metastable structures such as nano-sized grains, and even creative food processing. Sections in the conference covered such items as fundamentals, mathematical modeling, equipment and instrumentation, advanced materials and processes, composite materials, casting densification, surface treatments, HIP bonding, and competing technologies. Forty five papers were processed separately for inclusion on the data base.

  4. Glass Coats For Hot Isostatic Pressing

    NASA Technical Reports Server (NTRS)

    Ecer, Gunes M.

    1989-01-01

    Surface voids sealed from pressurizing gas. Coating technique enables healing of surface defects by hot isostatic pressing (HIP). Internal pores readily closed by HIP, but surface voids like cracks and pores in contact with pressurizing gas not healed. Applied to casting or weldment as thick slurry of two glass powders: one melts at temperature slightly lower than used for HIP, and another melts at higher temperature. For example, powder is glass of 75 percent SiO2 and 25 percent Na2O, while other powder SiO2. Liquid component of slurry fugitive organic binder; for example, mixture of cellulose acetate and acetone. Easy to apply, separates voids from surrounding gas, would not react with metal part under treatment, and easy to remove after pressing.

  5. Hot isostatic pressing of titanium based materials

    SciTech Connect

    Froes, F.H.; Widmer, R.; Hebeisen, J.

    1996-12-31

    The importance of titanium in demanding aerospace and terrestrial applications is presented, and the necessity to reduce cost to increase use is discussed. Hot isostatic pressing (HIP`ing) can be utilized with titanium based materials to obtain cost reduction and to enhance performance. The science/technology of various facets of the titanium scenario where HIP`ing can be used to advantage is presented, including powder metallurgy, castings, metal matrix composites and use of thermochemical processing. The major application of HIP`ing for titanium based materials is in castings; followed by blended elemental concepts. Much work has been conducted on continuous fiber reinforced materials, with the first use in actual commercial components likely to occur in engine components. Discontinuously reinforced products are already in use in aerospace and terrestrial applications. For the future, developing processing such as mechanical alloying, nanostructured materials and rapidly solidified product could benefit from compaction by HIP`ing. 55 refs., 30 figs.

  6. 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.

  7. 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.

  8. Hot isostatic pressing of ceramic waste from spent nuclear fuel.

    SciTech Connect

    Bateman, K.J.; Rigg, R.H.; Wiest, J.D.

    2002-03-08

    Argonne National Laboratory has developed a process to immobilize waste salt containing fission products, uranium, and transuranic elements as chlorides in a glass-bonded ceramic waste form. This salt was generated in the electrorefining operation used in electrometallurgical treatment of spent Experimental Breeder Reactor-II fuel. The ceramic waste process culminated with a hot isostatic pressing operation. This paper reviews the installation and operation of a hot isostatic press in a radioactive environment. Processing conditions for the hot isostatic press are presented for non-irradiated material and irradiated material. Sufficient testing was performed to demonstrate that a hot isostatic press could be used as the final step of the processing of ceramic waste for the electrometallurgical spent fuel treatment process.

  9. Processing zirconia by sintering/hot isostatic pressing

    SciTech Connect

    Druschitz, A.P. )

    1988-05-01

    Sintering followed by hot isostatic pressing is a potential method for improving the mechanical properties of ceramic materials. Encouraging data have been presented and published but these data do not clearly show the origin of the benefits. Here, the effects of green density, time, temperature, and pressure on sintered density, grain size, and pore size of slip-cast ZrO{sub 2}-3 mol% Y{sub 2}O{sub 3} are described. The data demonstrate that, when compared to pressureless sintering, the sintering/hot isostatic pressing process produces an equivalent maximum density at reduced temperature and significant reductions in pore size, but no reduction in minimum grain size. The maximum density obtainable by the sinter/hot isostatic pressing process was limited by both open porosity and large pores; the processing conditions required to produce the maximum process advantage are described.

  10. 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.

  11. Hot Isostatic Pressing (HIP): Techniques, applications and economical use

    NASA Astrophysics Data System (ADS)

    Bousack, H.

    1985-01-01

    Hot isostatic pressing (HIP) is used to regenerate defect components exposed to dynamic and permanent static loads causing pore formation. It consists in compacting and bonding of powders and solids by encapsulation. The HIP-equipment consists of a high pressure vessel, an oven and a rare gas system for production of isostatic pressure. The compacting procedure using diffusion and deformation processes depends on the pressing temperature. It is used in the production of hard metals, superalloys, fiber composites and ceramic components. It saves energy material and costs.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Hot isostatic pressing of glass-zeolite composites

    SciTech Connect

    Hash, M.C.; Pereira, C.; Lewis, M.A.

    1996-05-01

    Glass-zeolite waste forms are being developed for immobilizing the chloride waste salt generated from the electrometallurgical treatment of spent fuel. Glass-zeolite composites with high densities were made using hot isostatic pressing (HIP) techniques. Processing parameters were investigated to yield desirable structural ceramic properties such as mechanical, chemical, and thermal stability. Limits for these parameters were determined by differential thermal and thermogravimetric analysis. The resulting ceramic properties such as bulk density, open or apparent porosity, and leach resistance were determined. In addition, phase equilibria and particle-size distribution were observed by optical light and electron microscopy. Pre-HIP processing techniques were also studied to ensure intimate mixing of the glass and zeolite powders. Particle size distributions resulting from dry blending procedure are appropriate for needed flow and packing characteristics.

  18. Hot-isostatic-press joining of cemented carbides

    SciTech Connect

    Miodownik, M.; Derby, B.

    1999-12-01

    Hot isostatic pressing (HIPing) is investigated as a technique for joining the cermet AC-15% Co to itself. Encapsulation of the specimens prior to HIPing was carried out using steel encapsulation, glass encapsulation, and self-encapsulation. The bonds were evaluated using a four-point-bend method. It is shown that the glass and steel encapsulation methods have a number of inherent problems which make them inappropriate for near net shape processing. In contrast the novel self-encapsulation method, described for the first time in this communication, is both simple and effective, producing joined material with bulk strength. The concept of self-encapsulation is potentially widely applicable for joining composite materials.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Dry Bag Isostatic Pressing for Improved Green Strength of Nuclear Fuel Pellets

    SciTech Connect

    G. W. Egeland; L. D. Zuck; W. R. Cannon; P. A. Lessing; P. G. Medvedev

    2010-11-01

    Dry bag isostatic pressing is proposed for mass production of nuclear fuel pellets. Dry bag isostatically pressed rods of a fuel surrogate (95% CeO2-5% HfO2) 200 mm long by 8 mm diameter were cut into pellets using a wire saw. Four different binder and two different CeO2 powder sources were investigated. The strength of the isostatically pressed pellets for all binder systems measured by diametral compression was about 50% higher than pellets produced by uniaxial dry pressing at the same pressure. It was proposed that the less uniform density of uniaxially pressed pellets accounted for the lower strength. The strength of pellets containing CeO2 powder with significantly higher moisture content was five times higher than pellets containing CeO2 powder with a low moisture content. Capillary pressure of the moisture was thought to supply the added binding strength.

  5. 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.

  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. 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.

  8. 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.

  9. Consolidation of Si3N4 without additives (by hot isostatic pressing)

    NASA Technical Reports Server (NTRS)

    Yeh, H. C.

    1983-01-01

    The potential of using hot isostatic pressing (HIP'ing) technique to produce dense silicon nitride materials without or with a reduced amount of additives (much less than 5 w/o) was investigated. Hot isostatic pressing technique can provide higher pressure and temperature than hot pressing can, thus has the potential of requiring less densification aids to consolidate Si3N4 materials. It was anticipated that if such dense materials could be fabricated, the high temperature strength of the material should be improved significantly. Observations on the phase transformation, densification behavior, and microstructures of the samples are also documented. Density, microhardness, four point bend strength (room temperature and 1370 C) were measured on selected densified materials.

  10. 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.

  11. Strength of hot isostatically pressed and sintered reaction bonded silicon nitrides containing Y2O3

    NASA Technical Reports Server (NTRS)

    Sanders, William A.; Mieskowski, Diane M.

    1989-01-01

    The hot isostatic pressing of reaction bonded Si3N4 containing Y2O3 produced specimens with greater room temperature strengths than those by high pressure nitrogen sintering of the same material. Average room temperature bend strengths for hot isostatically pressed reaction bonded silicon nitride and high pressure nitrogen sintered reaction bonded silicon nitride were 767 and 670 MPa, respectively. Values of 472 and 495 MPa were observed at 1370 C. For specimens of similar but lower Y2O3 content produced from Si3N4 powder using the same high pressure nitrogen sintering conditions, the room temperature strength was 664 MPa and the 1370 C strength was 402 MPa. The greater strengths of the reaction bonded silicon nitride materials in comparison to the sintered silicon nitride powder material are attributed to the combined effect of processing method and higher Y2O3 content.

  12. 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.

  13. 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)

  14. 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.

  15. Large scale densification of a nuclear waste ceramic by hot isostatic pressing

    SciTech Connect

    Hoenig, C.L.; Larker, H.T.

    1983-12-01

    Experimental results show that loaded bellows steel canisters, evacuated and sealed, can be cold-isostatically pressed before HIP from an initial density of 26 to 46% theoretical. Calcined powders are hygroscopic and may require degassing at 600 degrees C under vaccum, and residual gas, unless removed, is an impediment to HIP densification. Results also show that degassed synroc D powder in 50 kg quantities can be HIP densified to greater than 97% theoretical density at 1100 degrees C, 150 MPa, for 5h in a bellows canister without radial buckling. The authors believe that on the basis of this preliminary study, full-scale nuclear waste monoliths can be produced by HIP.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. Nd:YAG transparent ceramics fabricated by direct cold isostatic pressing and vacuum sintering

    NASA Astrophysics Data System (ADS)

    Ge, Lin; Li, Jiang; Zhou, Zhiwei; Liu, Binglong; Xie, Tengfei; Liu, Jing; Kou, Huamin; Shi, Yun; Pan, Yubai; Guo, Jingkun

    2015-12-01

    The sintering behavior of neodymium doped yttrium aluminum garnet (Nd:YAG) ceramics was investigated on the basis of densification trajectory, microstructure evolution and transmittance. Nd:YAG ceramics with in-line transmittance of 83.9% at 1064 nm and 82.5% at 400 nm were obtained by direct cold isostatic pressing (CIP) at 250 MPa and solid-state reactive sintering at 1790 °C for 30 h under vacuum. Compared with the porosity and the average pore diameter of the sample from uniaxial dry-pressing followed by CIP, those from direct CIP are much smaller. The samples pressed at 250 MPa were sintered from 1500 °C to 1750 °C for 0.5-20 h to study their sintering behavior. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. The relative density and the grain size increase with the increase of sintering time and temperature, and the sintering behavior is more sensitive to temperature than holding time. The mechanism controlling densification and grain growth at sintering temperature of 1550 °C is grain boundary diffusion.

  1. Experimenting with hot isostatically pressed (HIP) nano grained bismuth-telluride-based alloys

    NASA Astrophysics Data System (ADS)

    Virta, Jouko; Tervo, Jyrki

    2012-06-01

    Hot Isostatic Pressing (HIP) is was used for compaction of nano grained bismuth-telluride samples and results were compared to Spark Plasma Sintered (SPS) samples of the same materials. The powders were essentially the same as presented by Vasilevskiy1 et al, 2010. The (BixSb1-x)2(TeySe1-y)3 thermoelectric alloys studied in this article were produced by mechanical alloying under an inert atmosphere. The p-type alloy composition corresponds to x = 0.2, y = 1 and for the n-type material x = 0.95, y = 0.95. For HIP treatment the n-and p-type powders were encapsulated in copper cylinders under protective argon atmosphere. The HIP temperature was kept low to avoid excess grain growth of the materials. The electrical conductivity, carrier mobility, carrier concentration and Seebeck coefficient of HIP and SPS compacted materials were measured and compared.

  2. 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.

  3. 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.

  4. Preparation of dense bulk high T/sub c/ superconducting materials using hot isostatic pressing

    SciTech Connect

    Imam, M.A.; Sadananda, K.; Osofsky, M.

    1989-03-01

    It is important to improve the intergrain contact by eliminating internal porosity in sintered products. This is accomplished for Ba-Cu-O with Er or Nd, Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems using hot isostatic pressing (HIP). Sintered superconducting materials were encapsulated in an evacuated stainless steel or pyrex glass containers and processed in a HIP unit a high temperatures and pressures. Optimum HIP conditions to obtain bulk samples of nearly theoretical density were determined. Results indicate that in addition to density, HIP also improved T/sub c/. Furthermore, for the 1-2-3 system, the grain size is significantly reduced during HIP and is attributed to fracturing of course particles in the sintered compact due to high strain rates experienced during the pressurization. HIP materials can be machined to any shape and size and is being used for making specimens for J/sub c/ measurements and superconducting devices.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Powder processing of nitrides by hot isostatic pressing. (Latest citations from Engineered Materials abstracts). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the use of hot isostatic pressing to process metal nitrides. Citations discuss the fabrication of components for internal combustion, advanced heat, and gas turbine engines. Ceramic matrix composites are considered. (Contains a minimum of 77 citations and includes a subject term index and title list.)

  10. Grain-boundary cavitation and bloating of isostatically hot-pressed magnesia-partially-stabilized zirconia on air annealing

    SciTech Connect

    Hogg, C.L.; Stringer, R.K.; Swain, M.V.

    1986-03-01

    Commercially sintered magnesia-partially-stabilized zirconia was densified to near theoretical density by isostatic hot-pressing at 200 MPa and 1700/sup 0/C in argon. Subsequent air annealing above 1100/sup 0/C resulted in bloating of the material due to grain-boundary cavitation. Mass spectrometry of crushed samples detected the evolution of CO/sub 2/ and possibly CO on annealing; the hot-pressed material showed a sudden gas evolution above 1400/sup 0/C. Preliminary Auger and ESCA analysis identified the presence of carbon as graphite and an undefined carbide in both the sintered and the hot-pressed material.

  11. 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.

  12. 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.

  13. Mechanics of hot isostatic pressing of a densified unidirectional SiC/Ti composite

    SciTech Connect

    Bahei-El-Din, Y.A.; Dvorak, G.J.

    1995-07-01

    The effect of standard and modified hot isostatic pressing programs on local residual stresses is investigated with an axisymmetric micromechanical model of a unidirectional SCS6/Ti-15-3 composite, made of an elastic fiber and a thermo-viscoplastic matrix. The processing parameters studied include the cooling rate under sustained pressure, the magnitude of the hydrostatic stress, and the ratios of the axial transverse components. Local stresses in the fiber and in the matrix at their interface are evaluated after cooling from 980 C to room temperature, and during reheating to 500 and 980 C. As in the previous studies, the results indicate that inelastic deformation of the matrix along the cooling path, promoted here by slow cooling rates at sustained pressure, is responsible for reduction of the residual stresses in the fibrous composite. The magnitudes of the local residual stresses at room temperature are nearly linear functions of the logarithm of the cooling rate. Higher processing pressures also contribute to residual stress reduction, and especially so when the transverse pressure component is much higher than the axial.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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. Thermomechanical behavior of an austenitic stainless steel powder during hot isostatic pressing

    SciTech Connect

    Bouaziz, O.; Baccino, R.; Dellis, C.; Moret, F.

    1996-12-31

    Near-net-shape Hot Isostatic Pressing of powder can be an alternative technique to manufacture complex stainless steel parts for nuclear industry that are produced today by casting. Such a development requires the use of a numerical modelling code in order to predict the exact shape of the densified part. CEA/CEREM has developed a FEM code including Abouaf`s model to simulate the powder thermomechanical behavior. An extensive experimental program has been defined to determine Abouaf`s model parameters for a gas atomized austenitic stainless steel powder (AISI 316LN). In contrast to previous experimental works that were essentially focused on densification at stabilized forming temperature (1,125 C in the authors` case), this study was also concerned by the temperature and pressure raising stage in which the major deformations occur. This paper presents, in a first part, the HIP and uniaxial compression tests results in a very large temperature range from 800 to 1,125 C. The second part is devoted to the microstructural evolution of the material with temperature, pressure and density.

  1. Evaluation of the strength and creep-fatigue behavior of hot isostatically pressed silicon nitride

    SciTech Connect

    Ferber, M.K.; Jenkins, M.G. )

    1992-09-01

    This paper reports that the strength of a commerically available hot isostatically pressed silicon nitride was measured as a function of temperature. To evaluate long-term mechanical reliability of this material, the tensile creep and fatigue behavior was measured at 1150[degrees], 1260[degrees], and 1370[degrees]C. The stress and temperature sensitivities of the secondary (or minimum) creep strain rate were used to estimate the stress exponent and activation energy associated with the dominant creep mechanism. The fatigue characteristics were evaluated by allowing individual creep tests to continue until specimen failure. The applicability of the four-point load geometry to the study of strength and creep behavior was also determined by conducting a limited number of flexural creep tests. The tensile fatigue data revealed two distinct failure mechanisms. At 1150[degrees]C, failure was controlled by a slow crack growth mechanism. At 1260[degrees] and 1370[degrees]C, the accumulation of creep damage in the form of grain boundary cavities and cracks dominated the fatigue behavior. In this temperature regime, the fatigue life was controlled by the secondary (or minimum) creep strain rate in accordance with the Monkman-Grant relation.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Sintering and hot isostatic pressing of Bi2Sr2CaCu2O(x)

    NASA Astrophysics Data System (ADS)

    Nash, A. S.; Nash, P.; Poeppel, R. B.; Goretta, K. C.

    1991-01-01

    The Bi2Sr2CaCu2O(x) phase was synthesized by solid-state reaction of oxides and carbonates. Initial compositions of Bi:Sr:Ca:Cu were 4:3:3:6 and 2:1.7:1:2. Pellets of the pure powder and powder containing 2.5, 5, or 15 wt percent Ag were cold-pressed and either sintered or hot isostatically pressed (HIPped). For HIPping, the pellets were encased in thin Ag sheets, canned in steel, and pressed at 105 MPa in argon at 800 or 850 C. HIPping produced dense specimens, but sintering did not. HIPping induced very little decomposition of the Bi2Sr2CaCu2O(x), but a post-HIP anneal was needed to raise the transition temperature above 80 K. The Ag additions appeared to minimize microcracking during HIPping at 800 C. Little microcracking was evident in any of the specimens HIPped at 850 C.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Ultrafine-Grained Aluminum Processed by a Combination of Hot Isostatic Pressing and Dynamic Plastic Deformation: Microstructure and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Dirras, G.; Chauveau, T.; Abdul-Latif, A.; Gubicza, J.; Ramtani, S.; Bui, Q.; Hegedűs, Z.; Bacroix, B.

    2012-04-01

    Commercial-purity (99 wt pct), bulk, ultrafine-grained aluminum samples were produced by a two-step process that combines powder consolidation by hot isostatic pressing and dynamic plastic deformation. The compaction step yielded crystallographic texture-free specimens with an average grain size of approximately 2 μm. Then, some of the consolidated specimens were deformed dynamically at room temperature at an initial strain rate of 370 seconds-1 and up to an axial strain of ɛ = 1.25. After dynamic plastic deformation, the grain size and the dislocation density were approximately 500 nm and 1014 m-2, respectively. The yield strength was approximately 77 MPa for the as-consolidated sample, which increased up to approximately 103 MPa and 120 MPa for the impacted samples along the axial and radial directions, respectively. The compression stress as a function of strain showed saturation behavior for the axially deformed samples, whereas the specimens deformed along the radial direction exhibited significant strain softening. The latter behavior is explained mainly by the weakening of the crystallographic texture that occurred because of the strain-path change along the radial direction.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Plasma spraying of beryllium and beryllium-aluminum-silver alloys

    SciTech Connect

    Castro, R.G.; Stanek, P.W.; Elliott, K.E.; Jacobson, L.A.

    1993-12-31

    A preliminary investigation on plasma-spraying of beryllium and a beryllium-aluminum 4% silver alloy was done at the Los Alamos National Laboratory`s Beryllium Atomization and Thermal Spray Facility (BATSF). Spherical Be and Be-Al-4%Ag powders, which were produced by centrifugal atomization, were used as feedstock material for plasma-spraying. The spherical morphology of the powders allowed for better feeding of fine (<38 {mu}m) powders into the plasma-spray torch. The difference in the as-deposited densities and deposit efficiencies of the two plasma-sprayed powders will be discussed along with the effect of processing parameters on the as-deposited microstructure of the Be-Al-4%Ag. This investigation represents ongoing research to develop and characterize plasma-spraying of beryllium and beryllium-aluminum alloys for magnetic fusion and aerospace applications.

  7. 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.

  8. 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.

  9. Influence of Hot Isostatic Pressing on the Microstructure and Mechanical Properties of a Spray-Formed Al-4.5 wt.% Cu Alloy

    NASA Astrophysics Data System (ADS)

    Devaraj, S.; Sankaran, S.; Kumar, R.; Appa Rao, G.

    2014-04-01

    Al-4.5 wt.% Cu alloy was spray atomized and deposited at varied spray heights ranging from 300 to 390 mm. The average grain sizes decreased from ~ 29 to ~ 18 μm and a concomitant increase in the hardness and the 0.2% yield strength (YS) with increase in the spray height. The respective hardness values of SF-300, SF-340, and SF-390 are 451 ± 59, 530 ± 39, and 726 ± 39 MPa and the YS are 108 ± 7, 115 ± 8, and 159 ± 10 MPa. The transmission electron micrographs revealed the morphological changes of the Al2Cu phase from irregular shaped to small plate-shaped and then subsequently to spheroidal shape due to high undercooling encountered during spray atomization with increase in spray height from 300 to 390 mm. The porosity of the spray formed deposits varied between 5 to 12%. Hot isostatic pressing of spray deposits reduced the porosity to less than 0.5% without any appreciable increase in grain size. A dislocation creep mechanism seems to be operative during the secondary processing. A comparison between as-spray formed and hot isostatically pressed deposits exemplifies improvement in mechanical properties as a result of elimination of porosity without affecting the fine grain sizes achieved during the spray-forming process.

  10. Strength and phase stability of yttria-ceria-doped tetragonal zirconia/alumina composites sintered and hot isostatically pressed in argon-oxygen gas atmosphere

    SciTech Connect

    Hirano, M.; Inada, H. )

    1991-03-01

    Yttria-ceria-doped tetragonal zirconia ((Y,Ce)-TZP)/alumina (Al{sub 2}O{sub 3}) composites were fabricated by hot isostatic pressing at 1400{degrees} to 1450{degrees}C and 196 MPa in an Ar-O{sub 2} atmosphere using the fine powders prepared by hydrolysis of ZrOCl{sub 2} solution. The composites consisting of 25 wt% Al{sub 2}O{sub 3} and tetragonal zirconia with compositions 4 mol% YO{sub 1.5}{minus}4 mol% CeO{sub 2}-ZrO{sub 2} and 2.5 mol% YO{sub 1.5}{minus}5.5 mol% CeO{sub 2}-ZrO{sub 2} exhibited means fracture strength as high as 2000 MPa and were resistant to phase transformation under saturated water vapor pressure at 180{degrees}C (1 MPa). Postsintering hot isostatic pressing of (4Y, 4Ce)-TZP/Al{sub 2}O{sub 3} and (2.5Y, 5.5Ce)-TZP/Al{sub 2}O{sub 3} composites was useful to enhance the phase stability under hydrothermal conditions and strength.

  11. The effects of weld-repair and hot isostatic pressing on the fracture properties of Ti-5Al-2.5Sn ELI castings

    NASA Technical Reports Server (NTRS)

    Misra, M. S.; Lemeshewsky, S.; Bolstad, D.

    1982-01-01

    The Ti-5Al-2.5Sn extremely low interstitial alloy employed in the large castings which form the critical attachment fittings of the Space Shuttle External Tank was selected because of its high fracture resistance at cryogenic temperatures. Casting was selected over alternative fabrication methods because of its lower cost and adaptability to design changes, although it was found necessary to weld-repair surface and subsurface casting defects in order to reduce the scrap rate and maintain the inherent cost advantage of the castings. Hot Isostatic Pressing was experimentally found to heal the surface and internal defects of the castings, but did not improve tensile or fracture properties and was therefore rejected as a production technique. Production castings are instead weld-repaired, without any mechanical property degradation.

  12. 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.

  13. 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)

  14. 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.

  15. 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.

  16. Phase decomposition of γ-U (bcc) in U-10 wt% Mo fuel alloy during hot isostatic pressing of monolithic fuel plate

    NASA Astrophysics Data System (ADS)

    Park, Y.; Eriksson, N.; Newell, R.; Keiser, D. D.; Sohn, Y. H.

    2016-11-01

    Eutectoid decomposition of γ-phase (cI2) into α-phase (oC4) and γ‧-phase (tI6) during the hot isostatic pressing (HIP) of the U-10 wt% Mo (U10Mo) alloy was investigated using monolithic fuel plate samples consisting of U10Mo fuel alloy, Zr diffusion barrier and AA6061 cladding. The decomposition of the γ-phase was observed because the HIP process is carried out near the eutectoid temperature, 555 °C. Initially, a cellular structure, consisting of γ‧-phase surrounded by α-phase, developed from the destabilization of the γ-phase. The cellular structure further developed into an alternating lamellar structure of α- and γ‧-phases. Using scanning electron microscopy and transmission electron microscopy, qualitative and quantitative microstructural analyses were carried out to identify the phase constituents, and elucidate the microstructural development based on time-temperature-transformation diagram of the U10Mo alloy. The destabilization of γ -phase into α- and γ‧-phases would be minimized when HIP process was carried out with rapid ramping/cooling rate and dwell temperature higher than 560 °C.

  17. 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.

  18. 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.

  19. 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.

  20. Role of oxidation in the time-dependent failure behavior of hot isostatically pressed silicon nitride at 1,370 C

    SciTech Connect

    Wereszczak, A.A.; Breder, K.; Ferber, M.K. )

    1993-11-01

    Dynamic fatigue studies were conducted on a hot isostatically pressed silicon nitride in ambient air and inert environments using four-point flexure at 1,370 C. Specimens tested in ambient air exhibited a stressing rate dependence with decreased flexure strength with decreased stressing rates. All fracture surfaces of specimens tested in ambient air possessed a sweeping stress-oxidation damage zone that originated at the tensile side of each bend bar. In addition to this stress-oxidation damage, creep damage was concurrently observed in the specimens tested at the slower stressing rates, which appeared to further weaken the material. However, tests conducted in argon or nitrogen revealed flexure strength to be independent of the stressing rate. Creep damage was present at the slower stressing rates, but no stress-oxidation damage was evident similar to that observed on the specimens tested in ambient air. By decoupling the effects of oxidation and creep, it was evident that the former contributed to the formation of a detrimental stress-oxidation damage zone which significantly reduced the strength of this material at 1,370 C.

  1. Assessment of residual stresses on U10Mo alloy based monolithic mini-plates during Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Ozaltun, Hakan; Herman Shen, M.-H.; Medvedev, Pavel

    2011-12-01

    This article presents an assessment of the residual stresses in U-10 wt.% Mo (U10Mo) alloy based monolithic fuel plates and the elasto-plastic response to thermo-mechanical processing. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Understanding of the three-dimensional residual stress field is important for understanding the in-reactor performance of these plate-type fuels. To define fuel-cladding stress-strain characteristics, a thermo-mechanical finite element model was developed. During fuel plate fabrication, the hot pressing temperature approaches the melting temperature of the cladding, so that temperature dependent material properties were incorporated to improve the accuracy of the model. By using elasto-thermo-plastic material models, it was determined that the cladding material (Al6061-O) is subjected to tensile stresses that exceed its proportional limits. The fuel foil is subject to compressive stresses and remains below yield. The residual stresses in the plates are significant, and therefore, should not be neglected. In particular, the simulations indicate the presence of high stress gradients at the fuel/cladding interface, thus emphasizing the need for a high quality bond.

  2. ASSESSMENT OF RESIDUAL STRESSES ON U10MO ALLOY BASED MONOLITHIC MINI-PLATES DURING HOT ISOSTATIC PRESSING

    SciTech Connect

    Hakan Ozaltun; M.-H. Herman Shen

    2011-12-01

    This article presents an assessment of the residual stress field on U10Mo alloy based monolithic fuel plates and their elasto-plastic response to the thermo-mechanical fabrication process. Monolithic plate-type fuel for research and test reactors is a new fuel form proposed and developed by Idaho National Laboratory (INL) to accomplish higher uranium densities in the reactor core and allow multi-fold reduction of fuel enrichment. Identification of the 3D residual field is critical for benchmarking the new design and understanding the overall performance of the new plate-type fuels. To define fuel-cladding stress-strain characteristics, a new thermo-mechanical finite element model was developed. Material properties at high temperatures and material plasticity were considered carefully to improve the accuracy as the Hot Pressing temperature reaches the melting temperature of the cladding material. By using elasto-thermo-plastic material models, it was determined that the cladding material (AL6061-TO) is exposed to tensile stress field and exceeds its proportional limits, while the fuel foil (U10Mo) is under compression and remains below its yield limit. It was shown that the residual stresses would govern the overall behavior of the plates, and therefore, should not be neglected. In particular, the simulations have revealed the existence of stress gradients at the fuel/cladding interface, thus emphasizing the necessity of excellent bonding quality at the bond region for mechanical endurance.

  3. 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.

  4. 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.

  5. Growth and ferroelectric properties of Pb(Zr 0.52Ti 0.48)O 3 thin films crystallized on MgO single-crystal substrates by hot isostatic pressing

    NASA Astrophysics Data System (ADS)

    Kobune, Masafumi; Nishioka, Yusuke; Inoue, Tomoaki; Yazawa, Tetsuo

    2005-02-01

    Pb(Zr 0.52Ti 0.48)O 3 films with highly uniform c-axis orientation were fabricated on PbTiO 3 (PT) /Pt(1 0 0)/MgO(1 0 0) substrates from the amorphous state by hot isostatic pressing (HIP). The seven PZT films HIP-treated by single- and multi-step annealing indicated almost preferential (0 0 1) orientation with the degree of the c-axis orientation, α=0.89-0.99. The PZT films treated according to a one-step (700 °C) annealing program had a good squareness of the hysteresis curves. The PZT capacitors with high initial pulse-derived switchable polarization ( Qsw) and a simple Pt/PZT/PT/Pt/MgO structure fabricated using an HIP technique a one-step (700 °C) annealing program can be expected as high endurance ferroelectric ones for FeRAM applications.

  6. 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.

  7. 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.

  8. 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.

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

    SciTech Connect

    Gaume, R. M.; Lam, S.; Gascon, M.; Feigelson, R. S.; Setyawan, W.; Curtarolo, S.

    2013-01-15

    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.

  10. 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)

  11. 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.

  12. 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.)

  13. 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

  14. 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.

  15. 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).

  16. 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.

  17. Gravity field and isostatic state of Ethiopia and adjacent areas

    NASA Astrophysics Data System (ADS)

    Woldetinsae, G.; Götze, H.-J.

    2005-01-01

    Over 35,000 onshore and offshore gravity stations have been compiled in order to test isostatic models against geologic structures over a part of the Afro-Arabian shield. The area of Ethiopia covers an important part of this system because it contains the major section of the ≈5000 km Afro-Arabian rift and includes the transition between the Arabo-Nubian-Shield (ANS) and the Mozambique Belt (MB). Isostatic residual anomalies have been calculated using both Airy and Vening-Meinesz (flexural rigidity D = 10 22 Nm) models. The isostatic residual anomalies outline the major Precambrian belts, the Cenozoic rifts and associated major structures. Positive residual anomalies associated with the main Ethiopian Rift (MER) and Kenyan rift systems could be the expressions of an axial intrusive body and swarms of local faults and fractures. The residual anomalies indicate relative stability in the MER and increased tectonic activity in the areas of the Red Sea, Gulf of Aden and Afar. Near-zero isostatic residuals flank the MER and Kenya rifts and are found within the Danakil Alps and some plateau regions. The small mean isostatic residual anomaly (about 8 mGal) and the isostatic analysis show a slight positive bias indicating under compensation. The undercompensation may imply that there are upper crustal features that are not compensated regionally (probably supported by the rigidity of the lithosphere) and isostatic disequilibrium in the region. Therefore, the high topography of Ethiopia and East African plateau is partly compensated by thicker crust (broad negative isostatic regional anomaly) and partly by dynamic forces. The results of the qualitative interpretation form the basis of continuing three-dimensional gravity modelling and quantitative analysis that also integrates data from eastern Sudan.

  18. 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.

  19. 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!”

  20. 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.

  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. 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.

  3. 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.

  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. The Isostatic State of Ethiopia and Adjacent Areas

    NASA Astrophysics Data System (ADS)

    Woldetinsae, G.; Götze, H.-J.

    2003-04-01

    Over 35000 onshore and offshore gravity stations have been compiled in order to test isostatic models and perform geologic correlations over a large section of the Afro-Arabian shield. Ethiopia is an important part of this system because it contains the major section of the ca. 5000km Afro-Arabian rift and it includes the transition between the Arabo-Nubian-Shield (ANS) and Mozambique Belt (MB). Isostatic residual anomalies have been calculated using both Airy and Vening-Meinsez models. These anomalies outline the major Precambrian belts, the Cenozoic rifts and associated major structures. Positive residual anomalies associated with the Main Ethiopian Rift (MER) and Kenyan rift systems could be the expression of an axial intrusive body and swarms of local faults and fractures. The residual anomalies indicate relative stability in the MER and increased tectonic activity over the areas of the Red Sea, Gulf of Aden and Afar. Near-zero isostatic residuals flank the MER and Kenya rifts and are found within the Danakil Alps and some plateau regions. A series of NW-SE and E-W trending features are evident in the different isostatic residual maps. These parallel features include, from north to south, the Najid fault system, Red Sea axial zone, Melka Werer cross structure, the Anza rift and the Aswa shear zone. Additional NW-SE structures are apparent in the southern rift system, although these features are somewhat diffuse. Curvature enhanced maps are also useful for mapping fracture zones, major gravity lineaments and, in some cases, orientation of faults. Important areas from a metallogenesis point of view have been identified for further examination. The results of the qualitative interpretation form the basis of continuing three-dimensional gravity modelling and qualitative analysis that also integrates data from eastern Sudan.

  6. 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.

  7. 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.

  8. Supersymmetry protected topological phases of isostatic lattices and kagome antiferromagnets

    NASA Astrophysics Data System (ADS)

    Lawler, Michael J.

    2016-10-01

    I generalize the theory of phonon topological band structures of isostatic lattices to frustrated antiferromagnets. I achieve this with a discovery of a many-body supersymmetry (SUSY) in the phonon problem of balls and springs and its connection to local constraints satisfied by ground states. The Witten index of the SUSY model demands the Maxwell-Calladine index of mechanical structures. "Spontaneous supersymmetry breaking" is identified as the need to gap all modes in the bulk to create the topological isostatic lattice state. Since ground states of magnetic systems also satisfy local constraint conditions (such as the vanishing of the total spin on a triangle), I identify a similar SUSY structure for many common models of antiferromagnets including the square, triangluar, kagome, pyrochlore nearest-neighbor antiferromagnets, and the J2=J1/2 square-lattice antiferromagnet. Remarkably, the kagome family of antiferromagnets is the analog of topological isostatic lattices among this collection of models. Thus, a solid-state realization of the theory of phonon topological band structure may be found in frustrated magnetic materials.

  9. 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.

  10. 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…

  11. University Presses: Problems and Prospects.

    ERIC Educational Resources Information Center

    Meeker, Robert B.

    Historical information on university presses and their problems are considered. University presses in the United States have their roots in 15th century England when the Oxford University Press was established in 1478. The first U.S. press to use the term "university press" was Cornell University; the press operated from 1869 until it was closed…

  12. 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.

  13. Glacial Isostatic Adjustment and Contemporary Sea Level Rise: An Overview

    NASA Astrophysics Data System (ADS)

    Spada, Giorgio

    2016-08-01

    Glacial isostatic adjustment (GIA) encompasses a suite of geophysical phenomena accompanying the waxing and waning of continental-scale ice sheets. These involve the solid Earth, the oceans and the cryosphere both on short (decade to century) and on long (millennia) timescales. In the framework of contemporary sea-level change, the role of GIA is particular. In fact, among the processes significantly contributing to contemporary sea-level change, GIA is the only one for which deformational, gravitational and rotational effects are simultaneously operating, and for which the rheology of the solid Earth is essential. Here, I review the basic elements of the GIA theory, emphasizing the connections with current sea-level changes observed by tide gauges and altimetry. This purpose is met discussing the nature of the "sea-level equation" (SLE), which represents the basis for modeling the sea-level variations of glacial isostatic origin, also giving access to a full set of geodetic variations associated with GIA. Here, the SLE is employed to characterize the remarkable geographical variability of the GIA-induced sea-level variations, which are often expressed in terms of "fingerprints". Using harmonic analysis, the spatial variability of the GIA fingerprints is compared to that of other components of contemporary sea-level change. In closing, some attention is devoted to the importance of the "GIA corrections" in the context of modern sea-level observations, based on tide gauges or satellite altimeters.

  14. High School Press Freedom.

    ERIC Educational Resources Information Center

    Maurer, Diana J.

    This report focuses on controversial articles written by the high school press, decisions made by the courts regarding students' press freedoms, and reactions to the articles and rulings. Particular attention is given to two rulings concerning censorship of articles about students' sexual atttiudes and activities, the issue of prior restraint of…

  15. 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…

  16. 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…

  17. 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.

  18. Space-geodetic constraints on glacial isostatic adjustment in Fennoscandia.

    PubMed

    Milne, G A; Davis, J L; Mitrovica, J X; Scherneck, H G; Johansson, J M; Vermeer, M; Koivula, H

    2001-03-23

    Analysis of Global Positioning System (GPS) data demonstrates that ongoing three-dimensional crustal deformation in Fennoscandia is dominated by glacial isostatic adjustment. Our comparison of these GPS observations with numerical predictions yields an Earth model that satisfies independent geologic constraints and bounds both the average viscosity in the upper mantle (5 x 10(20) to 1 x 10(21) pascal seconds) and the elastic thickness of the lithosphere (90 to 170 kilometers). We combined GPS-derived radial motions with Fennoscandian tide gauge records to estimate a regional sea surface rise of 2.1 +/- 0.3 mm/year. Furthermore, ongoing horizontal tectonic motions greater than approximately 1 mm/year are ruled out on the basis of the GPS-derived three-dimensional crustal velocity field. PMID:11264528

  19. Space-Geodetic Constraints on Glacial Isostatic Adjustment in Fennoscandia

    NASA Astrophysics Data System (ADS)

    Milne, G. A.; Davis, J. L.; Mitrovica, Jerry X.; Scherneck, H.-G.; Johansson, J. M.; Vermeer, M.; Koivula, H.

    2001-03-01

    Analysis of Global Positioning System (GPS) data demonstrates that ongoing three-dimensional crustal deformation in Fennoscandia is dominated by glacial isostatic adjustment. Our comparison of these GPS observations with numerical predictions yields an Earth model that satisfies independent geologic constraints and bounds both the average viscosity in the upper mantle (5 × 1020 to 1 × 1021 pascal seconds) and the elastic thickness of the lithosphere (90 to 170 kilometers). We combined GPS-derived radial motions with Fennoscandian tide gauge records to estimate a regional sea surface rise of 2.1 +/- 0.3 mm/year. Furthermore, ongoing horizontal tectonic motions greater than ~1 mm/year are ruled out on the basis of the GPS-derived three-dimensional crustal velocity field.

  20. Segmentation of the Andean margin by isostatic models and gradients

    NASA Astrophysics Data System (ADS)

    Schaller, T.; Andersen, J.; Götze, H.-J.; Koproch, N.; Schmidt, S.; Sobiesiak, M.; Splettstößer, S.

    2015-04-01

    The gravity gradients of the South American continental margin are the highest on Earth. These gradients are proxies for the strong horizontal stresses due to the convergent movement of the Nazca plate and the overriding South American plate. The frequently occurring large earthquakes in this zone suggest a correlation of gravity anomalies and seismogenic structures which is the major target of our research. Numerical analyses of the Central Andean gravity field were conducted using different techniques such as isostatic calculations, inversion and edge detection while varying the key parameters of the respective methods. Also, a constrained 3D density model was built through forward modelling of the terrestrial Bouguer anomaly. The results point out that a Vening-Meinesz model with a rigidity of 1023 Nm fits optimally the isostatic behaviour of the Central Andes. For numerical inversion the following parameters provided best results: density contrasts between 430-500 kg/m3, compensation depths of 30-40 km and a 400/300-km-wavelength filter. Moho depths obtained from the different methods agree reasonably well in the continental and oceanic area but defer the most in the transition zone between the two. In this coastal area, north-south segmentation of the residual fields is evident. The respective gravity defined segments correspond well with the extent of large earthquake rupture planes in the southern part of the investigation area. We propose that this segmentation is reflected by changing thicknesses of high density crustal bodies modelled in the 3D density model. These old batholiths fit extremely well to high-velocity domains from seismic tomography. Further seismic asperity structures also display a good correlation with different features of the residual fields.

  1. A Guide to Press Relations.

    ERIC Educational Resources Information Center

    Fibre Box Association, Chicago, IL.

    Stressing that a positive press-relations program can be extremely helpful to businesses, this publication offers suggestions for establishing press contacts, preparing press releases, holding press conferences, illustrating a story, preparing materials for use in radio and television broadcasts, and developing policies to be followed in emergency…

  2. Coherent potential approximation of random nearly isostatic kagome lattice.

    PubMed

    Mao, Xiaoming; Lubensky, T C

    2011-01-01

    The kagome lattice has coordination number 4, and it is mechanically isostatic when nearest-neighbor sites are connected by central-force springs. A lattice of N sites has O(√N) zero-frequency floppy modes that convert to finite-frequency anomalous modes when next-nearest-neighbor (NNN) springs are added. We use the coherent potential approximation to study the mode structure and mechanical properties of the kagome lattice in which NNN springs with spring constant κ are added with probability P=Δz/4, where Δz=z-4 and z is the average coordination number. The effective medium static NNN spring constant κ(m) scales as P(2) for P≪κ and as P for P≫κ, yielding a frequency scale ω*~Δz and a length scale l*~(Δz)(-1). To a very good approximation at small nonzero frequency, κ(m)(P,ω)/κ(m)(P,0) is a scaling function of ω/ω*. The Ioffe-Regel limit beyond which plane-wave states become ill-defined is reached at a frequency of order ω*.

  3. Assessment of Glacial Isostatic Adjustment in Greenland using GPS

    NASA Astrophysics Data System (ADS)

    Khan, S. A.; Bevis, M. G.; Sasgen, I.; van Dam, T. M.; Wahr, J. M.; Wouters, B.; Bamber, J. L.; Willis, M. J.; Knudsen, P.; Helm, V.; Kuipers Munneke, P.; Muresan, I. S.

    2015-12-01

    The Greenland GPS network (GNET) was constructed to provide a new means to assess viscoelastic and elastic adjustments driven by past and present-day changes in ice mass. Here we assess existing glacial isostatic adjustments (GIA) predictions by analysing 1995-2015 data from 61 continuous GPS receivers located along the margin of the Greenland ice sheet. Since GPS receivers measure both the GIA and elastic signals, we isolate GIA, by removing the elastic adjustments of the lithosphere due to present-day mass changes using high-resolution fields of ice surface elevation change derived from satellite and airborne altimetry measurements (ERS1/2, ICESat, ATM, ENVISAT, and CryoSat-2). For most GPS stations, our observed GIA rates contradict GIA predictions; particularly, we find huge uplift rates in southeast Greenland of up to 14 mm/yr while models predict rates of 0-2 mm/yr. Our results suggest possible improvements of GIA predictions, and hence of the poorly constrained ice load history and Earth structure models for Greenland.

  4. Towards accurate observation and modelling of Antarctic glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    King, M.

    2012-04-01

    The response of the solid Earth to glacial mass changes, known as glacial isostatic adjustment (GIA), has received renewed attention in the recent decade thanks to the Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE measures Earth's gravity field every 30 days, but cannot partition surface mass changes, such as present-day cryospheric or hydrological change, from changes within the solid Earth, notably due to GIA. If GIA cannot be accurately modelled in a particular region the accuracy of GRACE estimates of ice mass balance for that region is compromised. This lecture will focus on Antarctica, where models of GIA are hugely uncertain due to weak constraints on ice loading history and Earth structure. Over the last years, however, there has been a step-change in our ability to measure GIA uplift with the Global Positioning System (GPS), including widespread deployments of permanent GPS receivers as part of the International Polar Year (IPY) POLENET project. I will particularly focus on the Antarctic GPS velocity field and the confounding effect of elastic rebound due to present-day ice mass changes, and then describe the construction and calibration of a new Antarctic GIA model for application to GRACE data, as well as highlighting areas where further critical developments are required.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. Reinventing the University Press.

    ERIC Educational Resources Information Center

    Bryant, Eric

    1994-01-01

    Discusses how librarians and university press staffers could cooperate to improve the scholarly communication system. Causes of system decline, the environment for cooperation, several change models, possible changes to the publish or perish tenure system, and the probability of a slow transition to a new scholarly communications model are…

  13. 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

  14. 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.

  15. 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).

  16. Importance of far-field topographic and isostatic corrections for regional density modelling

    NASA Astrophysics Data System (ADS)

    Szwillus, Wolfgang; Ebbing, Jörg; Holzrichter, Nils

    2016-10-01

    The long-wavelength gravity field contains information about processes in the sublithospheric 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-isostatic effect (TIE) and isostatic effects (IE) is a likely source of error. We constructed a global isostatic model and calculated global TIE and IE. 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 IE. 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 modelling, 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.

  17. 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

  18. 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.

  19. Isostatic gravity map of the Point Sur 30 x 60 quadrangle and adjacent areas, California

    USGS Publications Warehouse

    Watt, J.T.; Morin, R.L.; Langenheim, V.E.

    2011-01-01

    This isostatic residual gravity map is part of a regional effort to investigate the tectonics and water resources of the central Coast Range. This map serves as a basis for modeling the shape of basins and for determining the location and geometry of faults in the area. Local spatial variations in the Earth's gravity field (after removing variations caused by instrument drift, earth-tides, latitude, elevation, terrain, and deep crustal structure), as expressed by the isostatic anomaly, reflect the distribution of densities in the mid- to upper crust, which in turn can be related to rock type. Steep gradients in the isostatic gravity field often indicate lithologic or structural boundaries. Gravity highs reflect the Mesozoic granitic and Franciscan Complex basement rocks that comprise both the northwest-trending Santa Lucia and Gabilan Ranges, whereas gravity lows in Salinas Valley and the offshore basins reflect the thick accumulations of low-density alluvial and marine sediment. Gravity lows also occur where there are thick deposits of low-density Monterey Formation in the hills southeast of Arroyo Seco (>2 km, Marion, 1986). Within the map area, isostatic residual gravity values range from approximately -60 mGal offshore in the northern part of the Sur basin to approximately 22 mGal in the Santa Lucia Range.

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

    USGS Publications Warehouse

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

    2001-01-01

    An isostatic gravity map of the Death Valley groundwater model area was prepared from over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California.

  1. 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

  2. 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

  3. PR and the Student Press.

    ERIC Educational Resources Information Center

    Holland, Sandy

    1994-01-01

    Techniques for college public relations professionals to use in promoting a cooperative relationship with the student press are outlined. These include being available to students, having regular meetings, providing access to administrators, providing information that creates context for news, and releasing news directly to the student press. (MSE)

  4. 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…

  5. 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…

  6. A comparison of impulse drying to double felted pressing on pilot- scale shoe presses and roll presses

    SciTech Connect

    Orloff, D.I.

    1992-08-01

    Pilot-scale shoe press and roll press experiments have been conducted to compare impulse drying and double felted pressing. Both ceramic coated and Beloit Type C press rolls have been evaluated. The experiments show that impulse drying can provide significantly higher outgoing solids than double felled pressing at the same impulse. For example, at an impulse of 0.234 MPa seconds (34 psi seconds), sheets at an ingoing solids of 52% were impulse dried (using the Beloit Type C press roll) to 68% solids while optimized double felled pressing could only yield press dryness of, at most, 60%.

  7. 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.

  8. 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.

  9. 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

  10. A new approach to assess isostatic compensation of topography in continental domain from GOCE gravity gradients

    NASA Astrophysics Data System (ADS)

    Cadio, Cécilia; Saraswati, Anita; Cattin, Rodolphe; Mazzotti, Stéphane

    2016-11-01

    Estimating how topography is maintained provides insights into the different factors responsible for surface deformations and their relative roles. Here, we develop a new and simple approach to assess the degree of isostatic compensation of continental topography at regional scale from GOCE gravity gradients. We calculate the ratio between the radial gradient observed by GOCE and that calculated from topography only. From analytical and statistical formulations, simple relationships between this ratio and the degree of compensation are obtained under the Airy-Heiskanen isostasy hypothesis. Then, a value of degree of compensation at each point of study area can be easily deduced. We apply our method to the Alaska-Canada Cordillera and validate our results by comparison with a standard isostatic gravity anomaly model and additional geophysical information for this area. Both our GOCE-based results and the isostatic anomaly show that Airy-Heiskanen isostasy prevails for the Yukon Plateau whereas additional mechanisms are required to support topography below the Northwest Territories Craton and the Yakutat collision zone.

  11. 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

  12. Radial Electromagnetic Press for Ignitor

    NASA Astrophysics Data System (ADS)

    Pizzuto, A.; Capriccioli, A.; Gasparotto, M.; Palmieri, A.; Rita, C.; Roccella, M.; Coppi, B.

    1996-11-01

    The active vertical press included so far in the Ignitor design can be substituted advantageously (e.g. in terms of the machine maintenance procedure) by a radial electromagnetic press, without involving modification of the main machine components. Only the bracing ring of the radial mechanical preloading system that is permanently applied requires some changes. The radial press has to compensate for the reduced ring load (from 200 MN to 120 MN) and the original vertical press load of 35 MN. To get an equivalent preloading system, the radial press load has to be 140 MN, which is 25 MN higher, to account for the lower efficiency of the radial load. The current needed to originate the 140 MN force is about 3.2 MA. The press is active for 2 s starting from the plasma current rise. The temperature increase is about 20 ^oC. The stray field at the plasma border is well within the allowable value and can be easily compensated by varying slightly the current of one couple of poloidal coils. The new machine layout is illustrated and the electromagnetic and mechanical analyses carried out for the new configuration are given. Sponsored by ENEA, CNR and ASP, of Italy, and by the US DoE

  13. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  14. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  15. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  16. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  17. 7 CFR 550.29 - Press releases.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

  18. 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.

  19. 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.

  20. Density Structure, Isostatic Balance and Tectonic Models of the Central Tien Shan

    NASA Astrophysics Data System (ADS)

    Kaban, Mikhail K.; Yuanda, T. Reiza

    2014-11-01

    A new combined satellite-terrestrial model of the gravity field is used together with seismic data for construction of a density model of the lithosphere of the Central Tien Shan and for estimation of its isostatic balance. The Tien Shan is one of the most active intraplate orogens in the world, located about 1,500 km north of the convergence between Indian and Eurasian plate, and surrounded by stable Kazakh platform to the north and the Tarim block to the south. Although this area was extensively studied during recent decades, several principal problems, related to its structure and tectonics, remain unsolved up to now: (1) various geodynamic scenarios have been discussed so far to explain tectonic evolution, such as direct "crustal shortening," intracontinental subduction and some others, but no definite evidence for any of them has been found. (2) Still, it is not clear why Tien Shan grows so far from the plate boundary at the Himalayan collision zone. Gravity modeling can provide valuable constraints to resolve these questions. The results of this study show that: (1) there exists a very strong deflection of the Tien Shan lithosphere from isostatic equilibrium. At the same time, the patterns of the isostatic anomalies are very different in the Western and Central Tien Shan. The latter one is characterized by much stronger variations. The best fit of the modeling results is found for the model according to which the Tarim plate partially underthrusts the Central Tien Shan; (2) negative density anomalies in the upper mantle under the central block possibly relate to magmatic underplating during the initial stage of the tectonic evolution. Therefore, the weak lithosphere could be the factor that initiates mountain building far away from the collision zone. Alternatively, this might be a gap after detachment of the eclogised lower crust and lithospheric lid, which is filled with the hot asthenospheric material.

  1. 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.

  2. Isostaticity of constraints in amorphous jammed systems of soft frictionless Platonic solids.

    PubMed

    Smith, Kyle C; Fisher, Timothy S; Alam, Meheboob

    2011-09-01

    The average number of constraints per particle in mechanically stable amorphous systems of Platonic solids approaches the isostatic limit at the jamming point (→12), though average number of contacts are hypostatic. By introducing angular alignment metrics to classify the degree of constraint imposed by each contact, constraints are shown to arise as a direct result of local orientational order reflected in edge-face and face-face alignment angle distributions. With approximately one face-face contact per particle at jamming, chainlike face-face clusters form with finite extent--a signature of amorphous jammed systems.

  3. The Features of Carbon Nanotubes Grown in High Isostatic Pressure Apparatus from the Nanodiamond Powder

    NASA Astrophysics Data System (ADS)

    Buranova, Yu. S.; Kulnitskiy, B. A.; Perezhogin, I. A.; Bagramov, R. H.; Dubitsky, G. A.; Blank, V. D.

    2013-05-01

    Multiwalled carbon nanotubes were synthesized in high isostatic pressure (HIP) apparatus in nitrogen at 1650 °C and 2 MPa. The synthesis was performed with nanodiamonds as a precursor of carbon and with ferrocene as a catalyst. Transmission electron microscopy studies demonstrate that the product of the synthesis contains carbon nanotubes filled with iron-based nanoparticles. It was established that in the most of the cases these nanoparticles represent themselves iron carbide Fe3C (cementite). Several times we observed pure iron (γ- and ɛ-Fe) inside the nanotubes. The orientation of the iron and iron carbide particles with respect to the nanotubes axes was investigated.

  4. The increase in use of isostatic processing for aluminum alloy castings

    SciTech Connect

    Geaman, V.

    1996-12-31

    The castings industry originally perceived isostatic processing as a means of reducing scrap rates. Prior to the development of HIP`ing no other non-destructive technique was available which let to improved economics. However in recent years the emphasis has changed towards the exploitation of improved properties as design engineers realize that cast parts which have been HIP`d can develop capabilities similar to those of forged components. This paper presents experimental data regarding compaction during HIP and CIP processes, applied to various aluminum castings alloys which are used extensively in the Romanian automotive industry.

  5. 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.

  6. MohoIso: A MATLAB program to determine crustal thickness by an isostatic and a global gravitational model

    NASA Astrophysics Data System (ADS)

    Bagherbandi, Mohammad

    2012-07-01

    This paper focuses on the modeling of the boundary between Earth's crust and upper mantle using a gravimetric-isostatic model. Here a MATLAB code is presented based on the gravimetric-isostatic model i.e. the Vening Meinesz-Moritz model. Inverse problems in isostasy consist in making the isostatic anomalies to be zero under a certain isostatic hypothesis. The Vening Meinesz-Moritz problem is to determine the Moho depth such that the compensating attraction totally compensates the Bouguer gravity anomaly on the Earth's surface, implying that the isostatic anomaly vanishes on the Earth's surface. The main idea is easy but the theoretical analysis is somewhat difficult. Here a practical method to recover the Moho depth from the gravity data is used in the MATLAB code (MohoIso.m) based on the Vening Meinesz-Moritz method. The code has been designed based on different sub-codes. The body of the main code works according to the vectorization technique, because this technique causes that the speed of code increases. One of the important possible limitations for the code is over-flow and under-flow for higher degrees in the fully normalized associated Legendre function. This problem occurs in the subroutine applied in this study, it limits the numerical study up to degrees 1800-2000.

  7. Censorship and the Student Press.

    ERIC Educational Resources Information Center

    Oettinger, Lauren

    The First Amendment rights provided to journalists--freedom of speech and of the press--are fundamental beliefs held by Americans. What students learn in the government class, however, may not be what they learn as editors-in-chief of student newspapers. U.S. schools are being charged with the censorship of student publications at an…

  8. 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,…

  9. 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…

  10. The Alternative Press in Microform.

    ERIC Educational Resources Information Center

    Tsang, Daniel C.

    Presented is an analysis of what has been done regarding the preservation of alternative publications in microfilm. The alternative press was defined, for the purposes of this study, as "nonstandard, nonestablishment publications." Two projects undertaken to microfilm such publications, one by the Microphoto Division of Bell and Howell and the…

  11. Mars Observer Press Conference JPL

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Mars Observer mission spacecraft was primarily designed for exploring Mars and the Martian environment. The Mars Observer was launched on September 25, 1992. The spacecraft was lost in the vicinity of Mars on August 21, 1993 when the spacecraft began its maneuvering sequence for Martian orbital insertion. This videotape shows a press briefing, held after the spacecraft had not responded to attempts to communicate with it, to explain to the press the problems and the steps that were being taken to re-establish communication with the spacecraft. The communications had been shutdown prior to the orbital insertion burn to protect the instruments. At the time of the press conference, the communications system was still not operational, and attempts were being made to re-establish communication. Bob McMillan of the Public Affairs Office at JPL gives the initial announcement of the continuing communication problem with the spacecraft. Mr. McMillan introduces William Piotrowski, acting director of solar system exploration, who reiterates that there is indeed no communication with the Observer spacecraft. He is followed by Glenn Cunningham, the Project Manager of the Mars Observer who speaks about the attempts to re-establish contact. Mr. Cunningham is followed by Satenios Dallas, the Mission Manager for the Mars Observer Project, who speaks about the sequence of events leading up to the communication failure, and shows an animated video presenting the orbital insertion maneuvers. The briefing was then opened up for questions from the assembled press, both at JPL and at the other NASA Centers. The questions are about the possible reasons for the communication failure, and the attempts to restore communications with the spacecraft. Dr. Arden L. Albee, chief scientist for the Mars Observer Mission, joins the other panel members to answer questions. At the end of the press briefing the animation of the Mars orbital insertion is shown again.

  12. 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.

  13. 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

  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. Constrained optimisation of the parameters for a simple isostatic Moho model

    NASA Astrophysics Data System (ADS)

    Lane, R. J.

    2010-12-01

    In a regional-scale integrated 3D crustal mapping project for the offshore Capel-Faust region, approximately 800 km east of the Australian east coast, gravity data were being used by the Geoscience Australia Remote Eastern Frontiers team to evaluate the viability of an interpretation of the upper crustal sequence that had been derived from a network of 2D seismic lines. A preliminary gravity forward modelling calculation for this sequence using mass density values derived from limited well log and seismic velocity information indicated a long wavelength misfit between this response and the observed data. Rather than draw upon a mathematical function to account for this component of the model response (e.g., low order polynomial), a solution that would lack geological significance, I chose to first investigate whether the gravity response stemming from the density contrast across the crust-mantle boundary (i.e., the Moho) could account for this misfit. The available direct observations to build the Moho surface in the 3D geological map were extremely sparse, however. The 2D seismic data failed to provide any information on the Moho. The only constraints on the depth to this interface within the project area were from 2 seismic refraction soundings. These soundings were in the middle of a set of 11 soundings forming a profile across the Lord Howe Rise. The use of relatively high resolution bathymetry data coupled with an Airy-Heiskanen isostatic model assumption was investigated as a means of defining the form of the Moho surface. The suitability of this isostatic assumption and associated simple model were investigated through optimisation of the model parameters. The Moho depths interpreted from the seismic refraction profile were used as the observations in this exercise. The output parameters were the average depth to the Moho (Tavg), upper crust density (RHOzero), and density contrast across the lower crust and upper mantle (RHOone). The model inputs were a grid

  16. Apollo 11 preflight press conference

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The three prime crewmen of the Apollo 11 lunar landing mission participate in a pre-flight press conference in the bldg 1 auditorium on July 5, 1969. Left to right, are Astronauts Neil A. Armstrong, commander; Edwin E. Aldrin Jr., lunar module pilot; and Michael Collins, command module pilot. The box-like enclosure surrounding the three astronauts was part of elaborate precautions in effect to reduce the possibility of exposing the crewmen to infectious disease in the preflight period.

  17. 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…

  18. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  19. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  20. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  1. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  2. Attention that Indicators Receive in the Press

    ERIC Educational Resources Information Center

    Hendriks, Maria; Barzano, Giovanna; Brumana, Emanuela; Cremonesi, Claudia

    2004-01-01

    With the release of each edition of Education at a Glance, the Office for Economic Co-operation and Development (OECD) prepares a press briefing to be used for the international press release and which individual countries in preparing their national press releases can also use. Similarly, the European Union prepares a summary, not for use at the…

  3. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  4. An Empirical Model of Glacial-Isostatic Crustal Movements and Shore-Level Displacement in Scandinavia

    NASA Astrophysics Data System (ADS)

    Passe, T.; Moren, L.

    2002-05-01

    Crustal movements and shore-level displacement will affect subsurface conditions of importance for the performance and safety of deep geological repositories for spent nuclear fuel. To support performance and safety analysis an empirical model of the glacio-isostatic movements and shore-level displacement for the area covered by the Scandinavian ice sheet during the Weichselian glaciation has been developed. The purpose of the work was to compile data from different sites in Scandinavia to a generally applicable description of the evolution since the last deglaciation. The model is strictly empirical. The intention is not to explain the complex glacio-isostatic processes but merely to provide a tool for interpretations and evaluations of both geological observations and results from geophysical modelling. The model was initially based on detailed lake-tilting investigations. These made it possible to express the course of glacio-isostatic uplift in mathematical terms without using rheological assumptions. In addition to the lake-tilting information the model is based on 72 shore-level curves from all over Scandinavia and information concerning present relative uplift recorded by precision levelling and tide gauge data. The main uplift, still in progress, is mainly calculated from two factors designated the down load factor and the inertia factor. The down load factor represent the subsidence/uplift at the time for the maximal subsidence/uplift rate, and the inertia factor describes the evolution of the subsidence/uplift with time. There is a strong linear correlation between the inertia factor and lithosphere thickness. The model has been incorporated into a GIS (Geographic Information System) application, and can be illustrated together with other GIS data. The purpose of the modelling was to illustrate the course of events since the last deglaciation and the model is based on Late Weichselian and Holocen information. However, scenarios of past and future shore

  5. Soft modes and elasticity of nearly isostatic lattices: randomness and dissipation.

    PubMed

    Mao, Xiaoming; Xu, Ning; Lubensky, T C

    2010-02-26

    The square lattice with nearest neighbor central-force springs is isostatic and does not support shear. Using the coherent potential approximation (CPA), we study how the random addition, with probability P=(z-4)/4 (z=average number of contacts), of next-nearest-neighbor (NNN) springs restores rigidity and affects phonon structure. The CPA effective NNN spring constant kappa{m}(omega), equivalent to the complex shear modulus G(omega), obeys the scaling relation, kappa{m}(omega)=kappa{m}h(omega/omega{*}), at small P, where kappa{m}=kappa{m}{'}(0) approximately P{2} and omega{*} approximately P, implying nonaffine elastic response at small P and the breakdown of plane-wave states beyond the Ioffe-Regel limit at omega approximately omega{*}. We identify a divergent length l{*} approximately P{-1}, and we relate these results to jamming.

  6. 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.

  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. 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

  9. 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.

  10. Microbial diversity across a Canadian sub-Arctic, isostatically rebounding, soil transect

    NASA Astrophysics Data System (ADS)

    Trevors, J. T.; Kevan, P. G.; Tam, L.

    2010-05-01

    Seacoast to inland soil transects of 1 and 2 km were researched over 2 years to understand the microbial diversity in a post ice age, isostatically, rebounding, soil environment. Community level substrate utilization analysis and 16S rDNA eubacterial diversity were employed. The community level substrate analysis demonstrated that regardless of the location along the transect from seacoast to forest, sandy or peat soil, the microbial diversity (Shannon diversity index about 3) was virtually the same. Shannon diversity indexes based on PCR-DGGE analysis yielded values between about 0.6 and about 2 depending on the sand or peat soil type and the year the samples were collected and analyzed (2002 and 2003). Regardless of the genetic diversity, the soils exhibited similar metabolic capabilities. This is a good example of redundant, functional, physiology regardless of the species present at each location along the transects.

  11. Volcanism, isostatic residual gravity and regional tectonic setting of the Cascade volcanic province

    USGS Publications Warehouse

    Blakely, R.J.; Jachens, R.C.

    1990-01-01

    A technique to locate automatically boundaries between crustal blocks of disparate densities was applied to upward continued isostatic residual gravity data. The boundary analysis delineates a narrow gravitational trough that extends the length of the Pliocene and Quaternary volcanic arc from Mount Baker in northern Washington to Lassen Peak in California. Gravitational highs interrupt the trough at two localities: a northwest trending high in southern Washington and a northeast trending high between Mount Shasta and Lassen Peak. The gravity sources may reflect upper crustal structures older than the High Cascades, possibly relicts from earlier accretionary events or more recent crustal deformation, that have actively influenced the spatial location of more recent volcanism. Much of the Pliocene and Quaternary volcanism of the Cascade arc has concentrated on or near contacts between crustal blocks of disparate density. These contacts may promote the ascension of magma to the Earth's surface. -from Authors

  12. 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.

  13. 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.

  14. 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.

  15. Topographic/isostatic evaluation of new-generation GOCE gravity field models

    NASA Astrophysics Data System (ADS)

    Hirt, C.; Kuhn, M.; Featherstone, W. E.; GöTtl, F.

    2012-05-01

    We use gravity implied by the Earth's rock-equivalent topography (RET) and modeled isostatic compensation masses to evaluate the new global gravity field models (GGMs) from European Space Agency (ESA)'s Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite gravimetry mission. The topography is now reasonably well-known over most of the Earth's landmasses, and also where conventional GGM evaluation is prohibitive due to the lack (or unavailability) of ground-truth gravity data. We construct a spherical harmonic representation of Earth's RET to derive band-limited topography-implied gravity, and test the somewhat simplistic Airy/Heiskanen and Pratt/Hayford hypotheses of isostatic compensation, but which did not improve the agreement between gravity from the uncompensated RET and GOCE. The third-generation GOCE GGMs (based on 12 months of space gravimetry) resolve the Earth's gravity field effectively up to spherical harmonic degree ˜200-220 (˜90-100 km resolution). Such scales could not be resolved from satellites before GOCE. From the three different GOCE processing philosophies currently in use by ESA, the time-wise and direct approaches exhibit the highest sensitivity to short-scale gravity recovery, being better than the space-wise approach. Our topography-implied gravity comparisons bring evidence of improvements from GOCE to gravity field knowledge over the Himalayas, Africa, the Andes, Papua New Guinea and Antarctic regions. In attenuated form, GOCE captures topography-implied gravity signals up to degree ˜250 (˜80 km resolution), suggesting that other signals (originating, e.g., from the crust-mantle boundary and buried loads) are captured as well, which might now improve our knowledge on the Earth's lithosphere structure at previously unresolved spatial scales.

  16. Interaction between climate, volcanism, and isostatic rebound in Southeast Alaska during the last deglaciation

    NASA Astrophysics Data System (ADS)

    Praetorius, Summer; Mix, Alan; Jensen, Britta; Froese, Duane; Milne, Glenn; Wolhowe, Matthew; Addison, Jason; Prahl, Fredrick

    2016-10-01

    Observations of enhanced volcanic frequency during the last deglaciation have led to the hypothesis that ice unloading in glaciated volcanic terrains can promote volcanism through decompression melting in the shallow mantle or a reduction in crustal magma storage time. However, a direct link between regional climate change, isostatic adjustment, and the initiation of volcanism remains to be demonstrated due to the difficulty of obtaining high-resolution well-dated records that capture short-term climate and volcanic variability traced to a particular source region. Here we present an exceptionally resolved record of 19 tephra layers paired with foraminiferal oxygen isotopes and alkenone paleotemperatures from marine sediment cores along the Southeast Alaska margin spanning the last deglacial transition. Major element compositions of the tephras indicate a predominant source from the nearby Mt. Edgecumbe Volcanic Field (MEVF). We constrain the timing of this regional eruptive sequence to 14.6-13.1 ka. The sudden increase in volcanic activity from the MEVF coincides with the onset of Bølling-Allerød interstadial warmth, the disappearance of ice-rafted detritus, and rapid vertical land motion associated with modeled regional isostatic rebound in response to glacier retreat. These data support the hypothesis that regional deglaciation can rapidly trigger volcanic activity. Rapid sea surface temperature fluctuations and an increase in local salinity (i.e., δ18Osw) variability are associated with the interval of intense volcanic activity, consistent with a two-way interaction between climate and volcanism in which rapid volcanic response to ice unloading may in turn enhance short-term melting of the glaciers, plausibly via albedo effects on glacier ablation zones.

  17. 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.

  18. 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.

  19. 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

  20. Spherical harmonic modelling to ultra-high degree of Bouguer and isostatic anomalies

    NASA Astrophysics Data System (ADS)

    Balmino, G.; Vales, N.; Bonvalot, S.; Briais, A.

    2012-07-01

    The availability of high-resolution global digital elevation data sets has raised a growing interest in the feasibility of obtaining their spherical harmonic representation at matching resolution, and from there in the modelling of induced gravity perturbations. We have therefore estimated spherical Bouguer and Airy isostatic anomalies whose spherical harmonic models are derived from the Earth's topography harmonic expansion. These spherical anomalies differ from the classical planar ones and may be used in the context of new applications. We succeeded in meeting a number of challenges to build spherical harmonic models with no theoretical limitation on the resolution. A specific algorithm was developed to enable the computation of associated Legendre functions to any degree and order. It was successfully tested up to degree 32,400. All analyses and syntheses were performed, in 64 bits arithmetic and with semi-empirical control of the significant terms to prevent from calculus underflows and overflows, according to IEEE limitations, also in preserving the speed of a specific regular grid processing scheme. Finally, the continuation from the reference ellipsoid's surface to the Earth's surface was performed by high-order Taylor expansion with all grids of required partial derivatives being computed in parallel. The main application was the production of a 1' × 1' equiangular global Bouguer anomaly grid which was computed by spherical harmonic analysis of the Earth's topography-bathymetry ETOPO1 data set up to degree and order 10,800, taking into account the precise boundaries and densities of major lakes and inner seas, with their own altitude, polar caps with bedrock information, and land areas below sea level. The harmonic coefficients for each entity were derived by analyzing the corresponding ETOPO1 part, and free surface data when required, at one arc minute resolution. The following approximations were made: the land, ocean and ice cap gravity spherical

  1. [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

  2. 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

  3. 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…

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

    NASA Astrophysics Data System (ADS)

    Steffen, H.; Wu, P. P. C.; Wang, H.

    2015-12-01

    Knowledge of the Glacial Isostatic Adjustment (GIA) process allows us to understand mantle rheology and dynamics, ice sheet thickness history and climate change. In order to further constrain GIA models and improve our current knowledge of GIA, more observations (e.g. relative sea-levels (RSL), GPS, gravity measurements, tide-gauges) are desirable to resolve the following parameters of GIA: 1.Ice thickness, 2.Lithospheric thickness, 3.Radial viscosity profile (background viscosity profile for modeling), 4.Lateral viscosity changes in view of thermal versus chemical origin of the 3D structures in the mantle.We discuss global sensitivities of 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 the four parameters above for up to nine dedicated times. Assuming an observational accuracy of 2 m of RSL data of all ages (based on analysis of currently available data), we highlight areas (or optimal locations) 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.

  5. Glacial isostatic adjustment of the British Isles: new constraints from GPS measurements of crustal motion

    NASA Astrophysics Data System (ADS)

    Bradley, S. L.; Milne, G. A.; Teferle, F. N.; Bingley, R. M.; Orliac, E. J.

    2009-07-01

    We compared estimates of crustal velocities within Great Britain based on continuous global positioning system (CGPS) measurements to predictions from a model of glacial isostatic adjustment (GIA). The observed and predicted values for vertical motion are highly correlated indicating that GIA is the dominant geodynamic process contributing to this field. In contrast, motion of the Eurasian plate dominates the horizontal motion component. A model of plate motion was adopted to remove this signal in order to estimate intraplate horizontal motion associated with GIA. However, a coherent pattern of horizontal motion was not evident in the resulting velocity field. We adopted a recently published model of the British-Irish ice sheet to predict vertical crustal motion for a large number of spherically symmetric Earth viscosity models. Our results show that the adopted ice model is capable of producing a high-quality fit to the observations. The CGPS-derived estimates of vertical motion provide a useful constraint on the average value of viscosity within the upper mantle. Values of model lithospheric thickness and lower mantle viscosity are less well resolved, however. A suite of predictions based on an alternative ice model indicates that the vertical motion data are relatively insensitive to uncertainties in the ice loading history and so the constraints on upper mantle viscosity are robust.

  6. 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.

  7. 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.

  8. Glacial isostatic adjustment associated with the Barents Sea ice sheet: A modelling inter-comparison

    NASA Astrophysics Data System (ADS)

    Auriac, A.; Whitehouse, P. L.; Bentley, M. J.; Patton, H.; Lloyd, J. M.; Hubbard, A.

    2016-09-01

    The 3D geometrical evolution of the Barents Sea Ice Sheet (BSIS), particularly during its late-glacial retreat phase, remains largely ambiguous due to the paucity of direct marine- and terrestrial-based evidence constraining its horizontal and vertical extent and chronology. One way of validating the numerous BSIS reconstructions previously proposed is to collate and apply them under a wide range of Earth models and to compare prognostic (isostatic) output through time with known relative sea-level (RSL) data. Here we compare six contrasting BSIS load scenarios via a spherical Earth system model and derive a best-fit, χ2 parameter using RSL data from the four main terrestrial regions within the domain: Svalbard, Franz Josef Land, Novaya Zemlya and northern Norway. Poor χ2 values allow two load scenarios to be dismissed, leaving four that agree well with RSL observations. The remaining four scenarios optimally fit the RSL data when combined with Earth models that have an upper mantle viscosity of 0.2-2 × 1021 Pa s, while there is less sensitivity to the lithosphere thickness (ranging from 71 to 120 km) and lower mantle viscosity (spanning 1-50 × 1021 Pa s). GPS observations are also compared with predictions of present-day uplift across the Barents Sea. Key locations where relative sea-level and GPS data would prove critical in constraining future ice-sheet modelling efforts are also identified.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

  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. 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.

  17. Volcanism, isostatic residual gravity, and regional tectonic setting of the Cascade volcanic province

    SciTech Connect

    Blakely, R.J.; Jachens, R.C. )

    1990-11-10

    A technique to locate automatically boundaries between crustal blocks of disparate densities was applied to upward continued isostatic residual gravity data. The boundary analysis delineates a narrow gravitational trough that extends the length of the Pliocene and Quaternary volcanic arc from Mount Baker in northern Washington to Lassen Peak in California. Gravitational highs interrupt the trough at two localities: A northwest trending high in southern Washington and a northeast trending high between Mount Shasta and Lassen Peak. The latter anomaly is one of a set of northeast trending anomalies that, within the Quaternary arc, appear related to volcanic segmentation proposed previously on the basis of spatial compositional distributions of volcanoes. These northeast trending anomalies extend hundreds of kilometers northeast of the arc, are caused by sources in the upper crust, and in some cases are related to exposed pre-Tertiary rocks. Segmentation models invoke geometric characteristics of the subducting plate as the primary factor controlling location and chemistry of volcanism, and these northeast trending gravity sources also may be a product of disturbance of the upper crust by the subduction process. More likely, the gravity sources may reflect upper crustal structures older than the High Cascades, possibly relicts from earlier accretionary events or more recent crustal deformation, that have actively influenced the spatial location of more recent volcanism. Much of the Pliocene and Quaternary volcanism of the Cascade arc has concentrated on or near contacts between crustal blocks of disparate density. These contacts may promote the ascension of magma to the Earth's surface.

  18. Volcanism, isostatic residual gravity, and regional tectonic setting of the Cascade Volcanic Province

    NASA Astrophysics Data System (ADS)

    Blakely, Richard J.; Jachens, Robert C.

    1990-11-01

    A technique to locate automatically boundaries between crustal blocks of disparate densities was applied to upward continued isostatic residual gravity data. The boundary analysis delineates a narrow gravitational trough that extends the length of the Pliocene and Quaternary volcanic arc from Mount Baker in northern Washington to Lassen Peak in California. Gravitational highs interrupt the trough at two localities: a northwest trending high in southern Washington and a northeast trending high between Mount Shasta and Lassen Peak. The latter anomaly is one of a set of northeast trending anomalies that, within the Quaternary arc, appear related to volcanic segmentation proposed previously on the basis of spatial and compositional distributions of volcanoes. These northeast trending anomalies extend hundreds of kilometers northeast of the arc, are caused by sources in the upper crust, and in some cases are related to exposed pre-Tertiary rocks. Segmentation models invoke geometric characteristics of the subducting plate as the primary factor controlling location and chemistry of volcanism, and these northeast trending gravity sources also may be a product of disturbance of the upper crust by the subduction process. More likely, the gravity sources may reflect upper crustal structures older than the High Cascades, possibly relicts from earlier accretionary events or more recent crustal deformation, that have actively influenced the spatial location of more recent volcanism. Much of the Pliocene and Quaternary volcanism of the Cascade arc has concentrated on or near contacts between crustal blocks of disparate density. These contacts may promote the ascension of magma to the Earth's surface.

  19. A comparison of impulse drying to double felted pressing on pilot- scale shoe presses and roll presses. Progress report, No. 6

    SciTech Connect

    Orloff, D.I.

    1992-08-01

    Pilot-scale shoe press and roll press experiments have been conducted to compare impulse drying and double felted pressing. Both ceramic coated and Beloit Type C press rolls have been evaluated. The experiments show that impulse drying can provide significantly higher outgoing solids than double felled pressing at the same impulse. For example, at an impulse of 0.234 MPa seconds (34 psi seconds), sheets at an ingoing solids of 52% were impulse dried (using the Beloit Type C press roll) to 68% solids while optimized double felled pressing could only yield press dryness of, at most, 60%.

  20. In the Stocks: Perilous Press Releases.

    ERIC Educational Resources Information Center

    Morton, Linda P.; Loving, Bill

    1994-01-01

    Reviews some of the legal responsibilities of public relations practitioners in the preparation of press releases. Discusses legal criteria for judging the fraudulence of press releases and discusses the timeframe for fraudulent action. Concludes with lessons that practitioners need to understand. (SR)

  1. 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…

  2. 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.

  3. 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

  4. Fluvial dissection, isostatic uplift, and geomorphological evolution of volcanic islands (Gran Canaria, Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Menéndez, Inmaculada; Silva, Pablo G.; Martín-Betancor, Moises; Pérez-Torrado, Francisco José; Guillou, Hervé; Scaillet, S.

    2008-11-01

    Digital analysis of torrential gullies ('barrancos') deeply incised into the volcanic Island of Gran Canaria (Canary Islands) allows us to extract the longitudinal profiles and pre-incision surfaces for individual basins, from which morphometric parameters (length, elevation, area, slope) have been calculated. Other derived parameters, such as ridgeline profiles, maximum incision values, volume removed by fluvial erosion, geophysical relief and isostatic uplift, have also been computed. Based on K/Ar ages for the island, well-constrained incision-uplift rates have been calculated by means of the combination of different methodological approaches commonly used in orogens and large mountain ranges. The geomorphological and morphometric analyses reveal that the island is clearly divided into four environmental quadrants determined by the combination of a couple of key-factors: the age of the volcanic surfaces and the climatic conditions. These factors determine a young sector covered with Plio-Quaternary platform-forming lavas (finished at 1.9-1.5 Ma) evolving under contrasting wet (NE) to dry (SE) climates, and an older sector, conserving the residual surfaces of the Miocene shield building (14.5-8.7 Ma) at the ridgelines, also subjected to wet (NW) and dry (SW) climates. Incision is related to the age zonation of the island. Maximum incisions (< 1200 m) are logically recorded in the older SW sector of the island, but incision rates are directly related to the climatic zonation, with maximum mean values in the wet Northern quadrants (0.18-0.12 mm/yr). The evaluation of the material removed by fluvial erosion for individual basins allows us to assess the consequent theoretical isostatic response in the different sectors of the island. The obtained uplift rates indicate that water availability (by drainage area and elevation) is a relevant controlling factor: the records from the wet Northern sectors show uplift values of between 0.09 and 0.03 mm/yr, whereas in the

  5. 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.

  6. Multiple Geodetic Observations for Identifying Glacial Isostatic Adjustment and the Causes of Sea-Level Change

    NASA Astrophysics Data System (ADS)

    Tamisiea, M. E.; Williams, S. D. P.; Hughes, C. W.; Bingley, R.; Blewitt, G.; Hammond, W. C.; Kreemer, C.

    2015-12-01

    Understanding the Earth's and ocean's response to past changes in global ice extent and ocean volume, collectively termed glacial isostatic adjustment (GIA), is necessary for interpreting observations of present-day sea level change. GIA has the largest effect on sea-level observations nearest the locations of the former ice sheets. Under the former loading centers, crustal uplift contributes to a local relative sea-level fall while the collapsing forebulge surrounding these centers accentuates a local sea-level rise. Some of the longest tide gauge records are in these regions. However, GIA also causes global deformation and geoid changes that introduce systematic differences between global averages of tide gauge and altimetry observations. Clearly accounting for the GIA contribution to sea-level change while identifying other present-day contributors is greatly assisted by additional geodetic measurements. Time-variable satellite gravity observations highlight the regional GIA signal, on length scales of hundreds of kilometers, while also locating water mass changes on the continents and the oceans. As the spatial density of GNSS observations has increased, it has become easier to discern the regional characteristics of crustal deformation (e.g. Blewitt et al. abstract in U009). Combined, these two observations allow for greater separation of GIA and water mass changes. More importantly for society, though, the regional crustal estimates could be combined with coastal altimetry products to create regional estimates of relative sea-level change, the observation most relevant for coastal planning. In this presentation we discuss how the various geodetic measurements complement each other and allow us to identify various components of sea level change, including GIA. We illustrate how the weakness of any individual observation component can be overcome by comparison with the other components. A sustained and global geodetic observing system is essential for

  7. 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.

  8. 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.

  9. GPS Measurement of Tectonic Deformation and Isostatic Rebound in Marie Byrd Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Luyendyk, B. P.

    2001-12-01

    The Ross embayment and western Marie Byrd Land are part of the West Antarctic rift system. The region is undergoing active deformation, but the rates and causes of deformation are essentially unknown. In December 1998 we installed three continuous and autonomous global positioning system (GPS) stations on outcrops in western Marie Byrd Land, with baselines between stations of about 100 kilometers. We recovered data for the sites in Marie Byrd Land during the 1998--1999 season and additional data in November 1999, November 2000, and January 2001. Results from three years of data collection indicate essentially no extension between McMurdo station (MBL4) and the network. The results show an overall length rate of -0.7+/- 3.5~mm/yr between MCM4 and the wMBL network. With additional years of measurements we should be able to discriminate whether this rate is near zero or not to about 1~mm/yr. We also expect to detect strain gradients within wMBL. The network also suggests a dome of uplift centered near the Rockefeller Mountains, with the maximum rate being in the Rockefeller Mountains of 12+/- 8~mm/yr. This is consistent with proposed post-glacial rebound for the region. The strain data from wMBL and the Transantarctic Mountains will enable us to construct models for tectonic extension and glacial rebound in the West Antarctic rift. The results will help determine whether active tectonic deformation is occurring in the Ross embayment. Crustal uplift could be occurring in western Marie Byrd Land due to isostatic rebound following the last glacial age. Tectonic extension, occurring in the embayment, could greatly influence global plate circuit calculations and constrain our understanding of the history of extension in the embayment and the consequent uplift history of the Transantarctic Mountains.

  10. The timing of the Black Sea flood event: Insights from modeling of glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Goldberg, Samuel L.; Lau, Harriet C. P.; Mitrovica, Jerry X.; Latychev, Konstantin

    2016-10-01

    We present a suite of gravitationally self-consistent predictions of sea-level change since Last Glacial Maximum (LGM) in the vicinity of the Bosphorus and Dardanelles straits that combine signals associated with glacial isostatic adjustment (GIA) and the flooding of the Black Sea. Our predictions are tuned to fit a relative sea level (RSL) record at the island of Samothrace in the north Aegean Sea and they include realistic 3-D variations in viscoelastic structure, including lateral variations in mantle viscosity and the elastic thickness of the lithosphere, as well as weak plate boundary zones. We demonstrate that 3-D Earth structure and the magnitude of the flood event (which depends on the pre-flood level of the lake) both have significant impact on the predicted RSL change at the location of the Bosphorus sill, and therefore on the inferred timing of the marine incursion. We summarize our results in a plot showing the predicted RSL change at the Bosphorus sill as a function of the timing of the flood event for different flood magnitudes up to 100 m. These results suggest, for example, that a flood event at 9 ka implies that the elevation of the sill was lowered through erosion by ∼14-21 m during, and after, the flood. In contrast, a flood event at 7 ka suggests erosion of ∼24-31 m at the sill since the flood. More generally, our results will be useful for future research aimed at constraining the details of this controversial, and widely debated geological event.

  11. 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.

  12. 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.

  13. 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.

  14. Formation of hyperextended rifted margins: Insights from flexural isostatic forward tectonic stratigraphic modeling and observations from fossil analogues

    NASA Astrophysics Data System (ADS)

    Mohn, G.; Kusznir, N. J.; Manatschal, G.

    2013-12-01

    The understanding of how continental lithosphere thins and ruptures leading to the formation of a new plate boundary represent a fundamental question in Earth Sciences. In particular the mechanisms controlling the extreme thinning of the continental crust, documented at many present-day rifted margins, are still poorly known. Many questions remain of the fundamental processes controlling the extensional deformation of the continental crust and lithosphere, including fault geometries and their evolution in space and time, the occurrence of decoupling horizons within the continental crust and the importance of depth dependent thinning processes. In this contribution, we aim to investigate the control of these key factors on continental crust and lithosphere thinning processes by coupling field observations from fossil analogues of rifted margins with flexural isostatic forward tectonic and stratigraphic modeling. Remnants of the Alpine Tethys rifted margins preserved in the Alpine orogeny in Western Europe represent an ideal natural laboratory providing direct access to rifted continental margin structures. This natural laboratory provides insights on fault geometry and kinematics, subsidence history and as well the nature of the basement rocks involved in rifting processes. These observations represent the input parameters to constrain the flexural isostatic forward modeling. Through this modeling, we produce isostatically balanced sections reproducing the geometries observed in the fossil analogues. Our results suggest that crust and lithosphere hyperextension results from the combination of both pure and simple shear deformation. The model predicts the critical role of intra-crustal decoupling horizons confirming the importance of depth-dependent thinning through polyphased rifting events. This ongoing work includes the analysis and modeling of present-day rifted margin examples such as the Iberia-Newfoundland rifted margins. These modeling results give critical

  15. 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.

  16. Conductive and ferromagnetic contributions of H in ZnCoO using H2 hot isostatic pressure

    NASA Astrophysics Data System (ADS)

    Chan Cho, Yong; Lee, Seunghun; Hyun Nahm, Ho; Jae Kim, Su; Hong Park, Chul; Yeon Lee, Su; Kim, Sung-Kyu; Ryong Cho, Chae; Koinuma, Hideomi; Jeong, Se-Young

    2012-03-01

    For highly H injected ZnCoO achieved by simultaneous high pressure (1000 bar) and annealing using a hot isostatic pressure (HIP), we report electrical and magnetic properties with first-principles calculation results. The HIP process increased the carrier concentration by ˜103 times and restored the conductivity up to that of H injected ZnO. Interestingly, with maintaining high conductivity, the extended HIP processing time significantly enhanced the short-ranged spin orderings of Co-H-Co complexes. Based on the experimental and theoretical results, we proposed the explanation for the relation magnetic characteristics and the behavior of hydrogen triggering spin ordering for spintronic applications.

  17. 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.

  18. The rotational feedback on linear-momentum balance in glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Martinec, Zdenek; Hagedoorn, Jan

    2015-04-01

    The influence of changes in surface ice-mass redistribution and associated viscoelastic response of the Earth, known as glacial-isostatic adjustment (GIA), on the Earth's rotational dynamics has long been known. Equally important is the effect of the changes in the rotational dynamics on the viscoelastic deformation of the Earth. This signal, known as the rotational feedback, or more precisely, the rotational feedback on the sea-level equation, has been mathematically described by the sea-level equation extended for the term that is proportional to perturbation in the centrifugal potential and the second-degree tidal Love number. The perturbation in the centrifugal force due to changes in the Earth's rotational dynamics enters not only into the sea-level equation, but also into the conservation law of linear momentum such that the internal viscoelastic force, the perturbation in the gravitational force and the perturbation in the centrifugal force are in balance. Adding the centrifugal-force perturbation to the linear-momentum balance creates an additional rotational feedback on the viscoelastic deformations of the Earth. We term this feedback mechanism as the rotational feedback on the linear-momentum balance. We extend both the time-domain method for modelling the GIA response of laterally heterogeneous earth models and the traditional Laplace-domain method for modelling the GIA-induced rotational response to surface loading by considering the rotational feedback on linear-momentum balance. The correctness of the mathematical extensions of the methods is validated numerically by comparing the polar motion response to the GIA process and the rotationally-induced degree 2 and order 1 spherical harmonic component of the surface vertical displacement and gravity field. We present the difference between the case where the rotational feedback on linear-momentum balance is considered against that where it is not. Numerical simulations show that the resulting difference

  19. The rotational feedback on linear-momentum balance in glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Martinec, Zdeněk; Hagedoorn, Jan

    2014-12-01

    The influence of changes in surface ice-mass redistribution and associated viscoelastic response of the Earth, known as glacial isostatic adjustment (GIA), on the Earth's rotational dynamics has long been known. Equally important is the effect of the changes in the rotational dynamics on the viscoelastic deformation of the Earth. This signal, known as the rotational feedback, or more precisely, the rotational feedback on the sea level equation, has been mathematically described by the sea level equation extended for the term that is proportional to perturbation in the centrifugal potential and the second-degree tidal Love number. The perturbation in the centrifugal force due to changes in the Earth's rotational dynamics enters not only into the sea level equation, but also into the conservation law of linear momentum such that the internal viscoelastic force, the perturbation in the gravitational force and the perturbation in the centrifugal force are in balance. Adding the centrifugal-force perturbation to the linear-momentum balance creates an additional rotational feedback on the viscoelastic deformations of the Earth. We term this feedback mechanism, which is studied in this paper, as the rotational feedback on the linear-momentum balance. We extend both the time-domain method for modelling the GIA response of laterally heterogeneous earth models developed by Martinec and the traditional Laplace-domain method for modelling the GIA-induced rotational response to surface loading by considering the rotational feedback on linear-momentum balance. The correctness of the mathematical extensions of the methods is validated numerically by comparing the polar-motion response to the GIA process and the rotationally induced degree 2 and order 1 spherical harmonic component of the surface vertical displacement and gravity field. We present the difference between the case where the rotational feedback on linear-momentum balance is considered against that where it is not

  20. 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.

  1. Progress on Antarctic Glacial Isostatic Adjustment and GRACE constraints on ice loss (Invited)

    NASA Astrophysics Data System (ADS)

    Ivins, E. R.; James, T. S.; Wahr, J. M.; Schrama, E. J.; Simon, K. M.; Landerer, F. W.; Watkins, M. M.; Wiese, D. N.

    2013-12-01

    Preparations for the Intergovermental Panel on Climate Change: Assessment Report 5 (IPCC AR5) has placed pressure on various research groups to accelerate the pace of their work in order to meet the Report deadlines. While this stimulates both positive and negative bi-products, it helped to focus attention to irreconcilable mass balance determinations for the Antarctic Ice Sheet (AIS) using space and airborne data. A glaring ';sore-thumb' for determining AIS trends from Gravity Recovery and Climate Experiment (GRACE) satellite data is the large signal of glacial isostatic adjustment (GIA) that is poorly constrained and possibly of the same magnitude as the present-day mass change. The report published in Science (vol. 338, pp. 1183-89) by S13 [Shepherd et al. 2013] met this challenge head-on by investing heavily in improving the GIA models with new GPS data, and new chronological constraints on ice sheet evolution across the Antarctic continent. This new data has emerged only within the last five years, and it came at a fortuitous time for advancing the IPCC AR5 goals. In this presentation we speak to the improvements developed in a recent JGR Solid Earth publication (14 June 2013). We extend the analysis using all of the official 05 releases of the analysis centers, including the JPL-mascon fields. The total error budgets of GIA correction are poorly determined, in spite of the great model improvements witnessed in the past 5 years. S12 reported the uncertainty for space-based sea level sourcing during 1992-2011 to Antarctica at roughly 0.23 mm/yr. Although GRACE 2002-2013 estimates vary, the uncertainly is about half this value. Here we examine how much of that uncertainty is still caused by GIA models and discuss how new classes of GIA models, and the collection of yet new GPS and ice constraint data for Antarctica, will enhance the value of a GRACE Follow-On mission. However, there will be a limit to constraining GIA, and a limit, therefore, to GIA error due to

  2. 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

  3. A data-driven model of present-day glacial isostatic adjustment in North America

    NASA Astrophysics Data System (ADS)

    Simon, Karen; Riva, Riccardo

    2016-04-01

    Geodetic measurements of gravity change and vertical land motion are incorporated into an a priori model of present-day glacial isostatic adjustment (GIA) via least-squares inversion. The result is an updated model of present-day GIA wherein the final predicted signal is informed by both observational data with realistic errors, and prior knowledge of GIA inferred from forward models. This method and other similar techniques have been implemented within a limited but growing number of GIA studies (e.g., Hill et al. 2010). The combination method allows calculation of the uncertainties of predicted GIA fields, and thus offers a significant advantage over predictions from purely forward GIA models. Here, we show the results of using the combination approach to predict present-day rates of GIA in North America through the incorporation of both GPS-measured vertical land motion rates and GRACE-measured gravity observations into the prior model. In order to assess the influence of each dataset on the final GIA prediction, the vertical motion and gravimetry datasets are incorporated into the model first independently (i.e., one dataset only), then simultaneously. Because the a priori GIA model and its associated covariance are developed by averaging predictions from a suite of forward models that varies aspects of the Earth rheology and ice sheet history, the final GIA model is not independent of forward model predictions. However, we determine the sensitivity of the final model result to the prior GIA model information by using different representations of the input model covariance. We show that when both datasets are incorporated into the inversion, the final model adequately predicts available observational constraints, minimizes the uncertainty associated with the forward modelled GIA inputs, and includes a realistic estimation of the formal error associated with the GIA process. Along parts of the North American coastline, improved predictions of the long-term (kyr

  4. Northwest outlet channels of Lake Agassiz, isostatic tilting and a migrating continental drainage divide, Saskatchewan, Canada

    NASA Astrophysics Data System (ADS)

    Fisher, Timothy G.; Souch, Catherine

    1998-10-01

    Lake cores obtained from the northwest outlet of glacial Lake Agassiz in northwest Saskatchewan, Canada, provide a minimum date for the cessation of the flood from the northwest outlet, and a chronology for abandonment of mid-Holocene channels that presently straddle the Mackenzie and Churchill drainage divide. The stratigraphy of a vibracore taken from Long Lake consists of a lower pebble gravel fining to massive sand, silty-clay and then fibrous peat. Wood fragments from the base of the clay yielded an accelerator mass spectrometry (AMS) date of 9120 BP. Because the lake is scour in origin and is in the head of the spillway, the date is considered to be a minimum estimate for cessation of the flood from the northwest outlet at the beginning of the Emerson Phase. A vibracore taken at Haas Lake in an abandoned channel surrounded by muskeg with no influent streams, consists of 0.8 m of stratified, pebble gravel containing abundant shell and wood fragments, overlain by 1.62 m of gyttja with a sharp, conformable lower contact. AMS dates range from 5590 BP from the topmost gravel to 3080 BP within the gyttja. The gravel is interpreted as fluvial, recording a river draining Wasekamio Lake north into the Clearwater River across the present-day drainage divide. Today, a drop of 2 m occurs from Wasekamio Lake southeast to Lac Ile-a-la-Crosse, along 150 km of lake basins parallel to the Cree Lake Moraine. The dates from Haas Lake suggest that before 5200 BP, the drainage divide was about 100 km further southeast, implying that during the Emerson Phase, lake level was controlled by a sill near Flatstone Lake at about 430 m instead of between Wasekamio Lake and the Clearwater River, as was previously proposed. Holocene differential isostatic uplift caused the flow reversal in the upper Churchill basin. Anastomosed channels at the mouth of rivers flowing north into lakes indicate that uplift is still active in the area today.

  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. Receiver function analysis of the crust and upper mantle in Fennoscandia - isostatic implications

    NASA Astrophysics Data System (ADS)

    Frassetto, Andrew; Thybo, Hans

    2013-11-01

    -like model for isostatic compensation. Because the Scandes mountains occupy the location of the ancient Caledonian orogeny, which created presumably much thicker crust and lithosphere by ca. 400 Ma, much of the dense lower crust or mantle lithosphere that is expected to form beneath large mountain belts must have been removed sometime afterwards to instill the current lithospheric architecture that underlies the region.

  7. 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.

  8. 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

  9. 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…

  10. 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…

  11. 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…

  12. Particle Characterization of Pressed Granular HMX

    NASA Astrophysics Data System (ADS)

    Burnside, N. J.; Son, S. F.; Skidmore, C. B.; Asay, B. W.

    1997-07-01

    Often, little material characterization is reported in studies that use granular explosives, such as deflagration-to-detonation transition (DDT) experiments. This lack of characterization makes modeling and interpretation of the experiments difficult. Further, very little is known about how particle size changes with compaction processes, even for quasi-static pressing. Changes in available surface area could significantly affect the initiation of such materials. In this work we report measurements of the particle size distribution of original granular HMX, as well as the size distribution of pressed (higher density) samples. Scanning electron microscope (SEM) pictures are presented and are found to be useful in interpreting the size distribution measurements of the granular HMX, as well as helping to more fully characterizing the state of the particles. We find that the particle size distribution changes significantly with pressing. That is, particles are observed to be highly fractured and damaged at higher pressed densities. Also, we have found that sample preparation can significantly affect size distribution measurements. In particular, even short duration sonication can have a significant effect on the measured size distributions of pressed HMX samples.

  13. 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

  14. 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…

  15. Speaking of a Free Press: 200 Years of Notable Quotations about Press Freedoms.

    ERIC Educational Resources Information Center

    American Newspaper Publishers Association Foundation, Washington, DC.

    Intended to summarize the ideals underlying the struggle for freedom of the press and to reinforce the basic Constitutional principles upon which the United States functions, this collection of quotations reflects the beliefs of prominent people throughout history who have championed press freedom, as well as the ideas of some who have opposed it.…

  16. 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.

  17. Using isostatic scenarios to assess coherence between continuous and instantaneous sea level indicators through the last interglacial

    NASA Astrophysics Data System (ADS)

    Williams, Felicity; Tamisiea, Mark E.; Rohling, Eelco J.; Hibbert, Fiona; Zhao, Cheng

    2014-05-01

    As a given volume of ice melt will not have a uniform impact on sea level, glacial isostatic adjustment is an essential tool for reconciling sea level indicators taken from multiple locations across the globe. We generate four ice loading histories based on the continuous ice volume record of de Boer, the δ18O stack of Lisiecki and Raymo, the composite relative sea level record of Waelbroeck, and our Red Sea relative sea level curve. Using these ice histories we model relative sea level curves for locations where fossil coral sea level indicators have been published and compiled into a standardised database. Although we apply screening criteria to the coral datapoints, preferentially focusing on those samples that are less likely to have undergone diagenic alteration, the fit between the sea level curves and the coral indicators is unsatisfactory. The relative sea level curves do not replicate the duration and amplitude of maximum sea level that is found in the coral record during MIS5e. We therefore explore three isostatic scenarios, whereby ice volume is reduced over the interglacial, the duration of the interglacial is extended, and the duration of the preceding glacial is extended in order to constrain possible explanations for the variations between the different records. We find that the continuous records require either a longer interglacial period or a combination of longer interglacial duration and less interglacial ice volume in order to more closely replicate the coral record.

  18. Modelling the density contrast and depth of the Moho discontinuity by seismic and gravimetric-isostatic methods with an application to Africa

    NASA Astrophysics Data System (ADS)

    Bagherbandi, Mohammad; Sjöberg, Lars E.

    2012-06-01

    The crustal thickness (Moho depth) is of interest in several geosciences applications, such as geography, geophysics and geodesy. Usually the crustal depth and density variations are estimated by seismic survey data. As such data collection is very time-consuming and expensive an attractive option could be to use a gravimetric/isostatic model. In this case, realistic estimates for the crustal density and Moho density contrast (MDC) are important. In this study, we first use the seismic crustal thickness of CRUST2.0 model as a known parameter in combination with gravimetric data in estimating the crust-mantle density contrast by the isostatic model of Vening Meinesz-Moritz. We present different models to estimate the MDC and its impact on the modelling of the gravimetric-isostatic Moho depth. The theory is applied to estimate the Moho depth of the African continental crust by using different models for the MDC: (a) constant value (0.6 g/cm3), (b) Pratt-Hayford's model, (c) CRUST2.0 as input to three gravimetric/isostatic models based on Vening Meinesz-Moritz theory. The isostatic models agree by 5.8-7.1 km in the rms with the regional seismic model at a resolution of 2° × 2°, and the smallest rms difference at a resolution of 1° × 1° is of 7.2 km. For comparison, the rms differences of CRUST2.0 and the regional seismic model are 8.8 and 9.1 km at the resolutions of 2° (interpolated) and 1°, respectively. The result suggests that the gravimetric/isostatic Moho model can be used in densification of the CRUST2.0 Moho geometry, and to improve it in areas with poor data.

  19. 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

  20. 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

  1. 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.

  2. Predicting the performance of belt filter presses using the Crown Press for laboratory simulation

    SciTech Connect

    Graham, T.M.

    1999-07-26

    Belt filter presses (BFPs) are among the most commonly used devices to dewater wastewater sludge. The concept used by a BFP to achieve dewatered cake solids is relatively simple; however, replicating this performance in the laboratory in order to predict the performance of a BFP with reasonable reliability has proven to be a challenge. The Crown Press is one tool that has been shown to replicate the performance of anaerobically digested sludge on a BFP. This study used the Crown Press to replicate and predict the performance of waste activated sludge (WAS) from the Mauldin Road wastewater treatment plant on BFPs. Several operational variables, including belt speed, belt tension, polymer type, and polymer dose, were changed on the Crown Press to predict how the changes on the BFP would affect performance. Two polymers were chosen to be tested on the BFPs at Mauldin Road based on Crown Press predictions. The first polymer performed the same as the plant`s current polymer in the lab, and the second performed better (achieved higher final cake solids) than the current polymer. These predictions were borne out in the BFP tests, showing that the Crown Press predictions were accurate. The Crown Press predictions were also compared to the predictions made by the capillary suction time (CST) and specific resistance to filtration (SRF) tests. The Crown Press provided more information regarding the affect of polymer type and dose on cake solids than either CST or SRF. The Crown Press was shown to be a viable tool to assess potential changes in BFP performance with WAS when operational variables change.

  3. 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…

  4. 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.

  5. Neo-Lysenkoism, IQ, and the Press.

    ERIC Educational Resources Information Center

    Davis, Bernard D.

    1983-01-01

    In "The Mismeasure of Man," a history of efforts to measure intelligence, Stephen Jay Gould is highly selective in his account, and tests for scientific truth by the standards of his own social and political convictions. Specifically, to combat racist approaches to theories of intelligence, Gould presses for equal and opposite bias. (Author/GC)

  6. Be Prepared to Meet the Press.

    ERIC Educational Resources Information Center

    Pedro, Nick J.

    1989-01-01

    Offers school administrators tips for sharpening their public relations skills. Educators interviewed by the press should do research beforehand, answer practice questions, listen before speaking, admit ignorance, make every statement count, be circumspect, ask for a review copy, attend to follow-up, keep a clipping file, and maintain open…

  7. Press kit kicks off new branding.

    PubMed

    Rees, Tom

    2004-01-01

    A smartly produced press kit resulted in unprecedented news coverage when Denver's Porter Adventist Hospital recently unveiled plans for an extensive 80 million dollars redevelopment. A news conference was held to announce this plan, along with the opening of the hospital's new emergency department. The overall effort is part of the new branding strategy of the 75-year-old hospital.

  8. 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…

  9. 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.

  10. 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)

  11. 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...

  12. 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…

  13. Freedom of the Press: Foundations and Attitudes.

    ERIC Educational Resources Information Center

    Gibson, Martin Leroy, Jr.

    This study reports the results of a national survey of the attitudes of five demographic groups toward freedom of the press. The groups are newsmen, state legislators, high school teachers, high school students, and the general public. The survey is broken into two parts, the first dealing with general principles (e.g., support for a law against…

  14. 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…

  15. 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…

  16. 7 CFR 58.421 - Press.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL... maintained in good repair and in a sanitary condition. Single service press cloths shall be used only once....

  17. The Press and the Bolivian National Revolution.

    ERIC Educational Resources Information Center

    Knudson, Jerry W.

    1973-01-01

    Social revolutions, which frequently use the press as a propaganda weapon, have been rare in Latin America despite the striking social inequalities of the region. Only three classic socioeconomic revolutions have unfolded in the hemisphere--in Mexico in 1910, in Bolivia in 1952, and in Cuba in 1959. Bolivia attempted to effect radical reforms…

  18. The Moral Universes of Libertarian Press Theory.

    ERIC Educational Resources Information Center

    Wuliger, Gregory T.

    1991-01-01

    Uses Kantian logic to analyze the statement of Libertarian press theory "Truth beats falsehood in a free marketplace of ideas" as a definition, an observation, and a universal truth. Notes three corresponding moral universes, with differing ethical obligations. Discusses strengths and weaknesses of each. Cautions media ethics analysts against…

  19. 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…

  20. Law of the Student Press. Second Edition.

    ERIC Educational Resources Information Center

    Student Press Law Center, Washington, DC.

    Noting dramatic changes in First Amendment protections for high school students and new legal issues facing college newspaper editors, this book describes in detail the legal rights and responsibilities of both the high school and college press. While the book is extensively footnoted, it intentionally avoids "legal-ese" and "brings law to life"…

  1. 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%).

  2. 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.

  3. 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.

  4. 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.

  5. Sensitivity of palaeotidal models of the northwest European shelf seas to glacial isostatic adjustment since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Ward, Sophie L.; Neill, Simon P.; Scourse, James D.; Bradley, Sarah L.; Uehara, Katsuto

    2016-11-01

    The spatial and temporal distribution of relative sea-level change over the northwest European shelf seas has varied considerably since the Last Glacial Maximum, due to eustatic sea-level rise and a complex isostatic response to deglaciation of both near- and far-field ice sheets. Because of the complex pattern of relative sea level changes, the region is an ideal focus for modelling the impact of significant sea-level change on shelf sea tidal dynamics. Changes in tidal dynamics influence tidal range, the location of tidal mixing fronts, dissipation of tidal energy, shelf sea biogeochemistry and sediment transport pathways. Significant advancements in glacial isostatic adjustment (GIA) modelling of the region have been made in recent years, and earlier palaeotidal models of the northwest European shelf seas were developed using output from less well-constrained GIA models as input to generate palaeobathymetric grids. We use the most up-to-date and well-constrained GIA model for the region as palaeotopographic input for a new high resolution, three-dimensional tidal model (ROMS) of the northwest European shelf seas. With focus on model output for 1 ka time slices from the Last Glacial Maximum (taken as being 21 ka BP) to present day, we demonstrate that spatial and temporal changes in simulated tidal dynamics are very sensitive to relative sea-level distribution. The new high resolution palaeotidal model is considered a significant improvement on previous depth-averaged palaeotidal models, in particular where the outputs are to be used in sediment transport studies, where consideration of the near-bed stress is critical, and for constraining sea level index points.

  6. 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.

  7. Geologic significance of new isostatic gravity and aeromagnetic maps of the Winnemucca 1[degree] by 2[degree] quadrangle, Nevada

    SciTech Connect

    Oliver, H.W.; Sikora, R.F. ); Robbins, S.L. )

    1993-04-01

    Since Wagini's 1986 Bouguer and isostatic gravity compilations of the Winnemucca 1[degree] by 2[degree] quadrangle, R. Sikora has provided an 1991 update that includes 133 new stations obtained in the Sonoma Range, Boulder Valley, and the Battle Mountain areas. Since that 1991 update, 371 additional stations have been obtained by S. Robbins in the Pine and Crescent Valley areas to look for possible gravity signatures of petroleum and gold deposits. All these data have been reduced and incorporated into a new isostatic gravity map of the quadrangle. This new compilation shows that the largest residual low of 32 mGal occurs over petroleum-bearing Pine Valley, although nearly-as-large gravity lows (27--31 mGal) occur over Buena Vista, Pleasant, Reese River, and Grass Valleys. A new aeromagnetic compilation of the Winnemucca quadrangle is continued downward to 300 m above terrain and shows a number of magnetic highs associated with igneous rocks, both intrusive and extrusive. A nearly continuous north-northwest trending magnetic high of about 400 nT, known as the northern Nevada rift, cuts across the quadrangle about 10 km east of Battle Mountain and is associated at some locations with Miocene basaltic and andesitic extrusive rocks. Three Miocene epithermal gold deposits are associated with this magnetic high at Mule Canyon, Fire Creek, and Bluckhorn. A smaller but broader magnetic high of about 200 nT at 300 m above terrain is located over the Tuscarora Mountains about 15 km northwest of Carlin. The maximum horizontal gradient of the pseudogravity transformation of the total magnetic field coincides with a series of ten productive gold mines known as the Carlin trend.

  8. 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

  9. Students Deserve Broad View in Advertising-Press Debate.

    ERIC Educational Resources Information Center

    Lynn, Jerry R.

    1979-01-01

    Argues that the advertising industry's influence on the press is primarily indirect and that journalism educators should divert student attention from the negative aspects of advertising's role in the press. (RL)

  10. 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.

  11. 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.

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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.…

  17. The Theater of Terror: Effects of Press Coverage.

    ERIC Educational Resources Information Center

    Weimann, Gabriel

    1983-01-01

    Compared attitudes before and after students read press clippings describing two separate terrorist incidents. Found that students exposed to press coverage tended to consider the event more noteworthy and to call for a solution. Concluded that press attention enhances the status of the people, problem, or cause behind a terrorist event. (PD)

  18. 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…

  19. 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…

  20. 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…

  1. 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.

  2. Remote plunger removal device for small-scale incremental pressing

    SciTech Connect

    Burnside, N.J.; Son, S.F.; Asay, B.W.

    1997-09-01

    Small-scale pressing of high explosives (HE) at Los Alamos National Laboratory (LANL) and elsewhere is routinely performed using pneumatic presses. Blast shields provide protection to the operator during the pressing procedure, but safety of the operator is a concern during removal of the plunger, which is currently performed manually. To minimize this risk, very high tolerances between the plunger and the die are required. These tolerances are often very costly, especially in the case of long, relatively narrow dies. The safety issue is an even greater concern with incremental pressing in which cleaning the die between increments is difficult or impossible. To better protect press operators, a device has been designed and constructed to allow remote plunger removal in a standard HE press. In this report the authors describe this modified press that allows remote removal of the plunger.

  3. 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.

  4. 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.

  5. 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.

  6. Abstracts of Suburban Press Research Series Papers Produced by the Suburban Press Research Center from July 1966 to February 1973. Suburban Press Research Series No. 14.

    ERIC Educational Resources Information Center

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

    Abstracts of 13 research investigations, speeches, and bibliographic resources, collected by the Suburban Press Research Center, are provided in this paper. Topics of discussion include the following aspects of the suburban press: pretrial coverage, characteristics of communities served by suburban newspapers, science news coverage, the role of…

  7. Rift flank uplift and isostatic response to glacial erosion: Creation of a high-elevation continental margin.

    NASA Astrophysics Data System (ADS)

    McGregor, E. D.; Nielsen, S. B.; Stephenson, R. A.; Clausen, O. R.; Petersen, K. D.; Macdonald, D. I. M.

    2012-04-01

    Southern Baffin Island lies to the west of Davis Strait, which is part of a sedimentary basin system, linking Labrador Sea and Baffin Bay. It developed during Cretaceous and Palaeocene rifting that culminated in a brief period of sea-floor spreading in the late Palaeocene and Eocene. To date the cause of the high elevation southeastern margin of Baffin Island has not been a focus of much research, whereas the origin and age of elevated topography on its conjugate west Greenland margin is a matter of lively debate. For west Greenland it has been argued by some authors, from interpretations of on- and offshore data (fission track, seismic and well), that onshore topography was created by tectonically-driven uplift in the Neogene. However, we have previously demonstrated that offshore seismic and well data along the Greenland margin of Davis Strait are consistent with a model of rifting followed by thermal subsidence and fjord excavation by glaciers, where Neogene tectonic uplift is not required. For southeastern Baffin Island, we have analysed offshore seismic reflection profiles, exploration well and gravity data along the western margin of Davis Strait and conclude that rift flank uplift of older remnant topography and subsequent isostatic response to glacial erosion have produced the present-day high elevation onshore. This interpretation of the offshore evolution conforms with an onshore evolution for which elevated topography is related to erosion of pre-existing topography.

  8. An improved and extended GPS-derived 3D velocity field of the glacial isostatic adjustment (GIA) in Fennoscandia

    NASA Astrophysics Data System (ADS)

    Lidberg, Martin; Johansson, Jan M.; Scherneck, Hans-Georg; Davis, James L.

    2007-03-01

    We present a new GPS-derived 3D velocity field for the Fennoscandia glacial isostatic adjustment (GIA) area. This new solution is based upon ˜3,000 days of continuous GPS observations obtained from the permanent networks in Fennoscandia. The period encompasses a prolongated phase of stable observation conditions after the northern autumn of 1996. Several significant improvements have led to smaller uncertainties and lower systematic errors in the new solutions compared to our previous results. The GPS satellite elevation cut-off angle was lowered to 10°, we fixed ambiguities to integers where possible, and only a few hardware changes occurred over the entire network. The GAMIT/GLOBK software package was used for the GPS analysis and reference frame realization. Our new results confirmed earlier findings of maximum discrepancies between GIA models and observations in northern Finland. The reason may be related to overestimated ice-sheet thickness and glaciation period in the north. In general, the new solutions are more coherent in the velocity field, as some of the perturbations are now avoided. We compared GPS-derived GIA rates with sea-level rates from tide-gauge observations, repeated precise leveling, and with GIA model computations, which showed consistency.

  9. Asperity generating upper crustal sources revealed by b value and isostatic residual anomaly grids in the area of Antofagasta, Chile

    NASA Astrophysics Data System (ADS)

    Sobiesiak, M.; Meyer, U.; Schmidt, S.; GöTze, H.-J.; Krawczyk, C. M.

    2007-12-01

    In our study we show that the locations of largest coseismic slip (asperities) on the fault plane of the Mw = 8.0 1995 Antofagasta earthquake in Northern Chile can be mapped by the spatial distribution of the seismic b value obtained from the aftershock sequence of the megathrust earthquake. These areas of high seismic moment release and concurrent high-b values are congruent with anomalies of the gravity isostatic residual (IR) field in the Antofagasta region. They are superimposed on the seismogenic part of the north Chilean subduction zone where the strongest coupling of the upper and lower plate is expected. The IR anomalies are interpreted to be caused by large Jurassic-Early Cretaceous batholiths which intruded into the upper crust. The observed positive correlations between high seismic b values, IR anomalies, and geologic structures enable us to propose a mechanical model for the generation of the asperities in the Antofagasta region. We suggest that the batholiths in conjunction with buoyant forces acting on the subducted slab of the Nazca plate are responsible for locking the interface where the asperities are located. This implies long-term conditions for the existence of the asperity generating tectonic situation. Concequently, the asperities around Antofagasta could be stationary features, at least for several seismic cycles. Hence we propose that the IR anomalies along the north Chilean convergent margin can be used as an indicator for high moment release and slip in future large earthquakes.

  10. Vertical motions in Northern Victoria Land inferred from GPS: A comparison with a glacial isostatic adjustment model

    USGS Publications Warehouse

    Mancini, F.; Negusini, M.; Zanutta, A.; Capra, A.

    2007-01-01

    Following the densification of GPS permanent and episodic trackers in Antarctica, geodetic observations are playing an increasing role in geodynamics research and the study of the glacial isostatic adjustment (GIA). The improvement in geodetic measurements accuracy suggests their use in constraining GIA models. It is essential to have a deeper knowledge on the sensitivity of GPS data to motionsrelated to long-term ice mass changes and the present-day mass imbalance of the ice sheets. In order to investigate the geodynamic phenomena in Northern Victoria Land (NVL), GPS geodetic observations were made during the last decade within the VLNDEF (Victoria Land Network for Deformation control) project. The processed data provided a picture of the motions occurring in NVL with a high level of accuracy and depicts, for the whole period, a well defined pattern of vertical motion. The comparison between GPS-derived vertical displacementsand GIA is addressed, showing a good degree of agreement and highlighting the future use of geodetic GPS measurements as constraints in GIA models. In spite of this agreement, the sensitivity of GPS vertical rates to non-GIA vertical motions has to be carefully evaluated.

  11. Where is the British national press?

    PubMed

    MacInnes, John; Rosie, Michael; Petersoo, Pille; Condor, Susan; Kennedy, James

    2007-06-01

    Although globalization has highlighted the danger of conflating state, society and nation, sociologists remain insufficiently alert to such banal nationalism. Newspapers offer a strong test case of the extent of diversity in the construction of state, national and social boundaries, since Billig and Anderson have argued they comprise a special case where their orientation to an audience simultaneously located in a state, society and nation allows them to reproduce a sense of national identity. However, despite the commonsense obviousness of the term, it proves remarkably difficult to define what the 'British national press' might comprise. Circulation density of titles varies substantially across different parts of the UK and editorial copy is altered to address diverse 'national' readerships. 'British' newspapers also circulate in other states, especially the Republic of Ireland. After reviewing how newspapers might be defined as 'national' and/or 'British', we conclude that both Anderson and Billig over-estimate the congruence, relevance and obviousness of state, society and national boundaries. If the conceptualization of such boundaries is problematic in the case of the press, it follows that it must be still more so for most other objects of sociological analysis, including that of 'society' itself.

  12. Formation of hyperextended rifted margins: Insights from flexural isostatic structural-stratigraphic modeling and observations from present-day rifted margins

    NASA Astrophysics Data System (ADS)

    Mohn, Geoffroy; Kusznir, Nick; Manatschal, Gianreto

    2014-05-01

    The understanding of how continental lithosphere extends, thins and ruptures leading to the formation of a new divergent plate boundary represent a fundamental question in Earth Sciences. In particular the mechanisms controlling the extreme pre-breakup stretching and thinning of the continental crust and lithosphere, documented at many present-day rifted margins, are still poorly known. Many questions remain of the fundamental processes controlling the extensional deformation of the continental crust and lithosphere, including fault geometries and their evolution in space and time, the occurrence of decoupling horizons within the continental crust and the importance of depth-dependent lithosphere thinning processes. We investigate the control of these key factors on continental crust and lithosphere thinning processes by combining seismic reflection and drill-hole observations from present-day Iberia-Newfoundland rifted margins with flexural isostatic forward tectonic and stratigraphic modeling. These observations made at present-day rifted margins constrain the input parameters used in the flexural isostatic forward modeling. At the same time, the forward tectonic and stratigraphic modeling provides validation of the interpretation of the seismic reflection data. Through this modeling, we produce isostatically and thermally balanced sections reproducing the geometries observed along the Iberia-Newfoundland rifted margins. Our results suggest that crustal and lithospheric thinning results from the combination of both pure- and simple-shear deformation. The model predicts the critical role of intra-crustal decoupling horizons confirming the importance of depth-dependent thinning through polyphased rifting events.

  13. Comparative analysis of Vening-Meinesz Moritz isostatic models using the constant and variable crust-mantle density contrast - a case study of Zealandia

    NASA Astrophysics Data System (ADS)

    Bagherbandi, Mohammad; Tenzer, Robert

    2013-04-01

    We compare three different numerical schemes of treating the Moho density contrast in gravimetric inverse problems for finding the Moho depths. The results are validated using the global crustal model CRUST2.0, which is determined based purely on seismic data. Firstly, the gravimetric recovery of the Moho depths is realized by solving Moritz's generalization of the Vening-Meinesz inverse problem of isostasy while the constant Moho density contrast is adopted. The Pratt-Hayford isostatic model is then facilitated to estimate the variable Moho density contrast. This variable Moho density contrast is subsequently used to determine the Moho depths. Finally, the combined least-squares approach is applied to estimate jointly the Moho depths and density contract based on a priori error model. The EGM2008 global gravity model and the DTM2006.0 global topographic/bathymetric model are used to generate the isostatic gravity anomalies. The comparison of numerical results reveals that the optimal isostatic inverse scheme should take into consideration both the variable depth and density of compensation. This is achieved by applying the combined least-squares approach for a simultaneous estimation of both Moho parameters. We demonstrate that the result obtained using this method has the best agreement with the CRUST2.0 Moho depths. The numerical experiments are conducted at the regional study area of New Zealand's continental shelf.

  14. 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.

  15. 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

  16. 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

  17. Photographic Study Of A Dead-Pressed Explosive

    NASA Astrophysics Data System (ADS)

    Swallowe, G. M.; Field, J. E.

    1983-03-01

    High speed photography in conjunction with electron microscopy and a pressure measuring technique have been used to investigate the differences between dead-pressed and non-dead-pressed samples of the primary explosive Mercury Fulminate (Hg Ful). Photographs of reaction propagation were taken in transmitted light using a specially adapted drop-weight machine with transparent anvils. The results of these experiments suggested a mechanism for dead-pressing in Hg Ful based on the microscopic internal structure of the compacted explosive.

  18. Steam press hand burns: a serious burn injury.

    PubMed

    Woods, J A; Cobb, A T; Drake, D B; Edlich, R F

    1996-01-01

    Steam presses cause full-thickness burns when the operator's extremity is caught between the buck and the head of the steam press. Patients with serious steam press burns should be referred to a regional burn center for excision of the full-thickness burn and coverage by either a split-thickness skin graft or a flap. The safety features in steam presses that could prevent this serious injury include: (1) emergency safety releases, (2) peripheral safety bars, and (3) two-hand operator control.

  19. STS-114: Discovery Launch Readiness Press Conference

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Michael Griffin, NASA Administrator; Wayne Hale, Space Shuttle Deputy Program Manager; Mike Wetmore, Director of Shuttle Processing; and 1st Lieutenant Mindy Chavez, Launch Weather Officer-United States Air Force 45th Weather Squadron are in attendance for this STS-114 Discovery launch readiness press conference. The discussion begins with Wayne Hale bringing to the table a low level sensor device for everyone to view. He talks in detail about all of the extensive tests that were performed on these sensors and the completion of these ambient tests. Chavez presents her weather forecast for the launch day of July 26th 2005. Michael Griffin and Wayne Hale answer questions from the news media pertaining to the sensors and launch readiness. The video ends with footage of Pilot Jim Kelly and Commander Eileen Collins conducting test flights in a Shuttle Training Aircraft (STA) that simulates Space Shuttle landing.

  20. Thermoelectric properties of pressed bismuth nanoparticles

    NASA Astrophysics Data System (ADS)

    Hostler, Stephen R.; Qu, Yu Qiao; Demko, Michael T.; Abramson, Alexis R.; Qiu, Xiaofeng; Burda, Clemens

    2008-03-01

    Theory predicts a substantial increase in the dimensionless figure of merit as the dimensionality and characteristic size of a material are decreased. We explore the use of bismuth nanoparticles pressed into pellets as potential increased efficiency thermoelectric materials. The figure of merit of these pellets is determined by independently measuring the electrical conductivity, thermal conductivity and Seebeck coefficient. The results from the nanoparticle sample are compared to microparticle-based samples. Both sample types show a slight reduction in thermal conductivity relative to bulk bismuth and a Seebeck coefficient near or slightly larger in magnitude than bulk bismuth. These changes are dwarfed by a hundred-fold decrease in the electrical conductivity due to porosity and an oxide layer on the particles. The low conductivity leads to figures of merit at least two orders of magnitude smaller than bulk bismuth. Oxide layer removal and reduced pellet porosity will be required to increase the figure of merit.

  1. Texaco presses projects for gasification process

    SciTech Connect

    Not Available

    1992-07-06

    This paper reports that Texaco Inc. continues to press international ventures for its gasification process. A combine of Italian companies plans an $800 million integrated gasification/combined cycle power plant at a refinery in Sicily that will use Texaco's process to gasify refinery residual to produce electrical power. Other Italian refiners are expected to follow suit with similar projects. Meanwhile, Texaco and Bitor America Corp., have signed a letter of agreement to develop integrated gasification/combined cycle electrical power generation projects. The venture plans to use Texaco's gasification process and Orimulsion, a boiler fuel that is an emulsion of Venezuelan heavy crude, water, and surfactant, as feedstock. Bitor, Boca Raton, Fla., and its parent, Bitumenes Orinoco SA, are units of Venezuela's state oil company Petroleos de Venezuela SA.

  2. 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.

  3. 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

  4. 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

  5. Optimal locations for absolute gravity measurements and sensitivity of GRACE observations for constraining glacial isostatic adjustment on the northern hemisphere

    NASA Astrophysics Data System (ADS)

    Steffen, Holger; Wu, Patrick; Wang, Hansheng

    2012-09-01

    Gravity rate of change is an important quantity in the investigation of glacial isostatic adjustment (GIA). However, measurements with absolute and relative gravimeters are laborious and time-consuming, especially in the vast GIA-affected regions of high latitudes with insufficient infrastructure. Results of the Gravity Recovery And Climate Experiment (GRACE) satellite mission have thus provided tremendous new insight as they fully cover those areas. To better constrain the GIA model (i.e. improve the glaciation history and Earth parameters) with new gravity data, we analyse the currently determined errors in gravity rate of change from absolute gravity (AG) and GRACE measurements in North America and Fennoscandia to test their sensitivity for different ice models, lithospheric thickness, background viscosity and lateral mantle viscosity variations. We provide detailed sensitivity maps for these four parameters and highlight areas that need more AG measurements to further improve our understanding of GIA. The best detectable parameter with both methods in both regions is the sensitivity to ice model changes, which covers large areas in the sensitivity maps. Also, most of these areas are isolated from sensitive areas of the other three parameters. The latter mainly overlap with ice model sensitivity and each other. Regarding existing AG stations, more stations are strongly needed in northwestern and Arctic Canada. In contrast, a quite dense network of stations already exists in Fennoscandia. With an extension to a few sites in northwestern Russia, a complete station network is provided to study the GIA parameters. The data of dense networks would yield a comprehensive picture of gravity change, which can be further used for studies of the Earth's interior and geodynamic processes.

  6. Modelling Late Cenozoic isostatic elevation changes in the Barents Sea and their implications for oceanic and climatic regimes: preliminary results

    NASA Astrophysics Data System (ADS)

    Butt, Faisal A.; Drange, Helge; Elverhøi, Anders; Otterå, Odd Helge; Solheim, Anders

    2002-08-01

    Late Cenozoic isostatic changes in the elevation of the Barents Sea are simulated using a numerical model. Isopach maps of the deposits off present-day Bear Island and Storfjorden troughs made earlier are used to calculate the thickness of sediment cover removed from the respective drainages basins at various time intervals during the last 2.3 Ma. Results indicate that Barents Sea was subaerially exposed at 2.3 Ma and major parts of it became submarine after 1 Ma. Barents Sea today receives around 40% of the warm and saline North Atlantic waters flowing into the Scotland-Greenland Ridge and about half of the Atlantic water entering the Arctic Ocean. It thus has an important role to play in the present-day ocean circulation pattern in the Polar North Atlantic region and water-mass transformations that take place in the Greenland-Iceland-Norwegian Sea and the Arctic Ocean. The effects of an uplifted Barents Sea on the oceanic regime and the Arctic sea-ice cover under the present-day forcings fields are studied using the Miami Isopycnic Coordinate Ocean Model. Preliminary results indicate that a subaerial Barents Sea causes an increased input of warm Atlantic waters into the Arctic Ocean through the Fram Strait which results in warming of the Atlantic water masses in the Arctic Ocean, followed by a reduction in the sea-ice cover. The obtained findings can be used to explain the apparent discrepancy in the late Cenozoic record of the sub-Arctic and Arctic regions whereby Fennoscandia, Iceland and Greenland are envisaged to have been covered by major ice sheets during late Pliocene whereas high Arctic areas such as Svalbard and NE Greenland were apparently free of any major ice.

  7. 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.

  8. Viscosity of the asthenosphere from glacial isostatic adjustment and subduction dynamics at the northern Cascadia subduction zone, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    James, Thomas S.; Gowan, Evan J.; Wada, Ikuko; Wang, Kelin

    2009-04-01

    Late glacial sea level curves located in the Cascadia subduction zone (CSZ) fore arc in southwestern British Columbia show that glacial isostatic adjustment (GIA) was rapid when the Cordilleran Ice Sheet collapsed in the late Pleistocene. GIA modeling with a linear Maxwell rheology indicates that the observations can be equally well fit across a wide range of asthenospheric thicknesses, provided that the asthenospheric viscosity is varied from 3 × 1018 Pa s for a thin (140 km) asthenosphere to 4 × 1019 Pa s for a thick (380 km) asthenosphere. Present-day vertical crustal motion predicted by the GIA models shows rates of a few tenths of a millimeter per year, consistent with previous analyses. The model viscosities largely pertain to the viscosity of the oceanic mantle beneath the subducting Juan de Fuca slab but include a contribution from the mantle wedge above the slab. For comparison, effective viscosities for the upper mantle due to the tectonic regime (subduction) were computed using the strain rates and temperatures of an independent geodynamic model of the CSZ with a wet olivine power law rheology. The effective viscosities agree well with GIA model viscosities of 1019 Pa s or less, corresponding to an asthenosphere of 100 or 200 km thickness. The agreement suggests a significant role for power law flow in the GIA response. Regardless of the microphysical mechanisms responsible for the GIA response, the viscosity values inferred from GIA can be applied to studies of the megathrust earthquake cycle because both processes take place on comparable time scales.

  9. 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…

  10. State Free Expression Laws and Scholastic Press Censorship.

    ERIC Educational Resources Information Center

    Paxton, Mark; Dickson, Tom

    2000-01-01

    Surveys high school newspaper advisors, finding remarkably similar attitudes, in states with scholastic freedom of press laws and states without such laws, regarding scholastic press freedom, the way they exercise their duty in overseeing the newspaper, censorship and self-censorship, and controversy over newspaper content. Finds differences in…

  11. 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.

  12. Nigerian Press under Imperialists and Dictators, 1903-1985.

    ERIC Educational Resources Information Center

    Ogbondah, Chris W.

    Comparing the Nigerian press during the colonial period of British rule and the post-independence period, a case study examined two press laws: the Newspaper Ordinance No. 10 of 1903, and Decree No. 4 of 1984 (Public Officers Protection against False Accusation Decree). Using qualitative research methodology, the study investigated how the…

  13. University Presses As "Gatekeepers of Ideas" within Society.

    ERIC Educational Resources Information Center

    Parsons, Paul

    University presses serve a prominent gatekeeping role in scholarly publishing because they, unlike commercial presses, can select books which transmit knowledge without being wholly captive to the marketplace. To analyze the cyclical flow that continually advances intellectual life, this selection procedure was examined with a study of the…

  14. University Presses See Opportunities in Shakeup in the Publishing World.

    ERIC Educational Resources Information Center

    McMillen, Liz

    1997-01-01

    Recent closings in the commercial publishing industry and reduction in serious nonfiction publications may open doors for university presses to fill the gap. University presses are already anticipating the changing market, reviewing book lists, and looking at new areas for publication development. Changes in the commercial publishing industry are…

  15. 19. REMAINS OF FLYWHEEL OF No. 1 PRESS PUMPING ENGINE. ...

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

    19. REMAINS OF FLYWHEEL OF No. 1 PRESS PUMPING ENGINE. GEARS ON EITHER SIDE OF THE FLYWHEEL WERE TURNED INTERMEDIATE GEARS WHICH POWERED THE PUMPS. - U.S. Steel Homestead Works, Press Shop No. 1, Along Monongahela River, Homestead, Allegheny County, PA

  16. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., hot bending and hot metal presses, forging presses and hammers, riveting machines and similar types of... equipment. Air controlling equipment shall be protected against foreign material and water entering the... shall be kept in good condition and free from obstructions, grease, oil, and water. (4) Overloading....

  17. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., hot bending and hot metal presses, forging presses and hammers, riveting machines and similar types of... equipment. Air controlling equipment shall be protected against foreign material and water entering the... shall be kept in good condition and free from obstructions, grease, oil, and water. (4) Overloading....

  18. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., hot bending and hot metal presses, forging presses and hammers, riveting machines and similar types of... equipment. Air controlling equipment shall be protected against foreign material and water entering the... surrounding floors shall be kept in good condition and free from obstructions, grease, oil, and water....

  19. Press Releases vs. Newspaper Coverage of California Supreme Court Decisions.

    ERIC Educational Resources Information Center

    Hale, F. Dennis

    1978-01-01

    A study comparing the coverage in newspapers and press releases regarding one year's decisions of the California Supreme Court revealed that the press releases influenced the kinds of decisions that were reported but not the quantity of coverage by the newspapers. (GT)

  20. 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

  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. 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

  3. The Role of the Black Press during the "Great Migration."

    ERIC Educational Resources Information Center

    Jones, Felecia G.

    Between the years of 1916 and 1918 southern blacks began populating the urban centers of the north in a movement known as the "Great Migration." This movement was significant to the development of the black press, for it was during this period that the black press became a protest organ and rose to its greatest level of prominence and influence.…

  4. 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…

  5. 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…

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Rotary press utilizing a flexible die wall.

    PubMed

    Amidon, G E; Smith, D P; Hiestand, E N

    1981-06-01

    A die with a flexible wall was constructed and evaluated on a specially modified instrumented rotary tablet press. The design permits an inward deflection of the die wall by a side punch, which rolls past a side compression roll during compression-decompression. The side compression roll is instrumented to monitor the applied side compression roll forces. On decompression, return of the die wall to its original position permits release of residual die wall pressure. The decreased residual die wall pressure can decrease fracture and capping of tablets for problem formulations. The performance was tested on three experimental formulations. For these formulations, tablets made in a conventional die exhibited severe capping problems. However, most tablets compressed in the special die were superior. With proper adjustment of punch and die wall compression forces, excellent tablets could be manufactured. The merits of the special die and modified tablet machine are substantiated, although this initial design did not provide adequate die wall pressure for all formulations. Further engineering efforts could result in practical production equipment.

  12. Filter-pressing of alumina dispersions

    SciTech Connect

    Fries, R.; Rand, B.

    1996-06-01

    The filter-pressing characteristics of aqueous alumina dispersions containing either submicron or nano-sized particles have been compared with respect to ionic strength. The highest green densities for both systems were achieved at electrolyte concentrations < 0.01 mol dm{sup -3} where long-range repulsive interparticle forces stabilize the slips. A slight increase in density with ionic strength in this range was attributed to an increase in the ratio of particle radius-to-double layer thickness, Ka. At higher electrolyte concentrations, above the critical coagulation concentration, the green densities dropped to significantly lower values due to the onset of flocculation and the formation of open particle networks characterized by strong attraction which resisted rearrangement into a dense green microstructure. The green densities of the compacts consolidated from the submicron dispersions at ionic strength > 1 mol dm{sup -3} were significantly higher than those prepared close to the critical coagulation concentration although the slips exhibited properties typical for a flocculated structure. The results may indicate the presence of short-range repulsive forces at high salt concentration for the submicron slips not accounted for by the classical DLVO-theory. In order to characterize the early stages of filter-cake consolidation the initial cake permeability was determined from the compaction curves.

  13. [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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 5. Interior, second floor. Pressed metal ceiling, and wooden floors ...

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

    5. Interior, second floor. Pressed metal ceiling, and wooden floors visible. Overhead light source toward rear of building indicates location of skylight. - 25-27 East Hanover Street (Commercial Building), 25-27 East Hanover Street, Trenton, Mercer County, NJ

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. Drill press in foreground is one of few machine tools ...

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

    Drill press in foreground is one of few machine tools in operating condition which is still operated occasionally for public demonstrations. - Thomas A. Edison Laboratories, Building No. 5, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

  6. 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

  7. 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

  8. 2ND FLOOR HALLWAY LOOKING EAST, NOTE PRESSED TIN CEILING ...

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

    2ND FLOOR HALLWAY LOOKING EAST, NOTE PRESSED TIN CEILING - New York State Soldiers & Sailors Home, Building No. 29, Department of Veterans Affairs Medical Center, 76 Veterans Avenue, Bath, Steuben County, NY

  9. 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

  10. Differential Suppression by Punishment of Nonconsummatory Licking and Lever Pressing

    ERIC Educational Resources Information Center

    Walters, Gary C.; Herring, Barbara

    1978-01-01

    Five experiments investigated the differential effects of shock punishment on nonconsummatory licking (dry licking) and lever pressing. Results support a motivationally based theory of punishment involving the role of incentive stimuli associated with the particular responses studied. (Editor/RK)

  11. 10. INTERIOR VIEW OF EYE PRESS AREA, SAME AS ABOVE ...

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

    10. INTERIOR VIEW OF EYE PRESS AREA, SAME AS ABOVE WITH MEN AT WORK: CRAIG TSCHAPPAT, HEATER; JEFF MILLER, OPERATOR; JOHN TOTH, SAWMAN - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  12. Looking north into oing press of the saw line in ...

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

    Looking north into o-ing press of the saw line in bay 7 of the main pipe mill building. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

  13. Oing press of the saw line in bay 7 of ...

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

    O-ing press of the saw line in bay 7 of the main pipe mill building looking northeast. - U.S. Steel National Tube Works, Main Pipe Mill Building, Along Monongahela River, McKeesport, Allegheny County, PA

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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).

  19. 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.

  20. 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

  1. 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.

  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. 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

  4. 22 CFR 9b.3 - Press correspondents employed by foreign media organizations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Press correspondents employed by foreign media... OF STATE PRESS BUILDING PASSES § 9b.3 Press correspondents employed by foreign media organizations... media organizations must: (a) Present to the Office of Press Relations, Department of State,...

  5. 22 CFR 9b.3 - Press correspondents employed by foreign media organizations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Press correspondents employed by foreign media... OF STATE PRESS BUILDING PASSES § 9b.3 Press correspondents employed by foreign media organizations... media organizations must: (a) Present to the Office of Press Relations, Department of State,...

  6. 22 CFR 9b.3 - Press correspondents employed by foreign media organizations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Press correspondents employed by foreign media... OF STATE PRESS BUILDING PASSES § 9b.3 Press correspondents employed by foreign media organizations... media organizations must: (a) Present to the Office of Press Relations, Department of State,...

  7. 22 CFR 9b.3 - Press correspondents employed by foreign media organizations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Press correspondents employed by foreign media... OF STATE PRESS BUILDING PASSES § 9b.3 Press correspondents employed by foreign media organizations... media organizations must: (a) Present to the Office of Press Relations, Department of State,...

  8. 22 CFR 9b.3 - Press correspondents employed by foreign media organizations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Press correspondents employed by foreign media... OF STATE PRESS BUILDING PASSES § 9b.3 Press correspondents employed by foreign media organizations... media organizations must: (a) Present to the Office of Press Relations, Department of State,...

  9. 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…

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Solutions to challenges facing a university digital library and press.

    PubMed

    D'Alessandro, M P; Galvin, J R; Colbert, S I; D'Alessandro, D M; Choi, T A; Aker, B D; Carlson, W S; Pelzer, G 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.

  16. 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.

  17. Using equal-channel angular pressing for refining grain size

    NASA Astrophysics Data System (ADS)

    Langdon, Terence G.; Furukawa, Minoru; Nemoto, Minoru; Horita, Zenji

    2000-04-01

    Equal-channel angular pressing is an effective tool for attaining ultrafine grain sizes in bulk materials. An important advantage of this technique over conventional metalworking processes, such as extrusion and rolling, is that very high strains may be attained without any concomitant change in the cross-sectional dimensions of the sample. The microstructures introduced by equalchannel angular pressing critically depend on a number of experimental factors, including the nature of the slip systems introduced during the pressing operation and the total strain imposed on the sample. These factors are illustrated by reference to experiments conducted on pure aluminum; results are also included to demonstrate the influence of alloying additions and especially the remarkably small grain sizes that may be achieved in materials having low rates of recovery.

  18. 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.

  19. 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.

  20. 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.

  1. Press chamber coating as external lubrication for high speed rotary presses: lubricant spray rate optimization.

    PubMed

    Jahn, T; Steffens, K-J

    2005-12-01

    Lubrication of the tooling (punches and dies) is necessary to produce tablets. The most commonly used lubricant is magnesium stearate. Adding and blending magnesium stearate to the tablet mass often has negative effects on the properties of the compressed tablets (e.g., decreasing the tensile strength of the tablet). To avoid these negative effects, external lubrication systems were developed. This study investigated the functionality and the influence of a new press chamber coating system called the PKB II. The major difference between the PKB II and previous systems is its ability to spray a mixture of powdered magnesium stearate and air directly onto the punches and dies which was determined to allow the running of the rotor at higher speeds. The data showed a clear correlation between the spray rate of the lubricant and the concentration of the magnesium stearate per tablet. The PKB II was designed to allow for adjustments, in order to optimize the spray rate, by using the ejection force. The concentration of magnesium stearate was reduced to approximately 0.04% per tablet, using the PKB II. Additionally, the most common negative effects, such as the decrease in tablet tensile strength, were avoided by using this system.

  2. 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.

  3. 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%). .

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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…

  10. 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…

  11. Student Press and Distribution Issues: Rights and Responsibilities.

    ERIC Educational Resources Information Center

    Bartlett, Larry D.

    1984-01-01

    This review analyzes case law in the area of student press and distribution and offers some guidelines for developing and implementing school policy and rules. Litigation is reviewed in order to clarify students' rights, limitations on administrative authority in matters of censorship and prior restraint, and actions in connection with writing and…

  12. The Press in Black Africa: Philosophy and Control.

    ERIC Educational Resources Information Center

    Wilcox, Dennis Lee

    This dissertation is a descriptive, comparative study of press-government relationships in the 34 nations of independent Black Africa south of the Sahara. Excluded from consideration are territories under European administration and those nations that have white minority governments. The 34 sovereign states are analyzed and systematically…

  13. Argonne Director Eric Isaacs addresses the National Press Club

    ScienceCinema

    Eric Isaccs

    2016-07-12

    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.

  14. 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…

  15. Book Review: Stars (Copyright 1985, Golden Press; New York)

    NASA Astrophysics Data System (ADS)

    Marigza, R. N., Jr.

    2009-06-01

    Stars is a part of the Golden Guides collection produced by Golden Press. It is a small 160 page paperback guide to the constellations, the sun, the moon, planets, and other celestial bodies. The book is convenient to carry along wherever you go, making it an easy to access reference material.

  16. Reconstructing Suicide: Reporting Suicide in the Israeli Press.

    ERIC Educational Resources Information Center

    Weimann, Gabriel; Fishman, Gideon

    1995-01-01

    Presents a content analysis of suicide stories in the Israeli Press (1955-90) and measures of real suicide events to highlight the selective, distorted, and reconstructed nature of reporting suicide. Argues that such reporting may account for at least some of the contradictory findings of studies on the impact of publicized suicide stories on…

  17. 19. SOUTHEAST TO CIRCA 1900 FOURSPINDLE PRODUCTION DRILL PRESS ALONG ...

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

    19. SOUTHEAST TO CIRCA 1900 FOUR-SPINDLE PRODUCTION DRILL PRESS ALONG EAST INTERIOR WALL OF FACTORY, SHOWING SHELVES AND BINS WITH TOOLS AND PARTS FOR PUMP AND WATER SYSTEM REPAIR. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  18. 20. NORTHEAST TO CIRCA 1900 FOURSPINDLE PRODUCTION DRILL PRESS ALONG ...

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

    20. NORTHEAST TO CIRCA 1900 FOUR-SPINDLE PRODUCTION DRILL PRESS ALONG EAST INTERIOR WALL OF FACTORY, SHOWING SHELVES AND BINS WITH TOOLS AND PARTS FOR PUMP AND WATER SYSTEM REPAIR. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  19. Ten Ways to Get Attention with Your Press Releases.

    ERIC Educational Resources Information Center

    Van Kooten, Valerie

    1994-01-01

    Recommends 10 steps that can increase chances of having press release published. Advises readers to use required format; determine what constitutes news; keep release short; include contact person in release; incorporate good quotes; send releases to right person; understand that release will be edited; time arrival of release; follow up with…

  20. 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…

  1. 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…

  2. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... equipment. Air controlling equipment shall be protected against foreign material and water entering the... tools are intended for placing and removing materials in and from the press. Hand feeding tools are not... hazard areas to lubricate material, punches or dies. (e) Inspection, maintenance, and modification...

  3. 29 CFR 1910.217 - Mechanical power presses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... equipment. Air controlling equipment shall be protected against foreign material and water entering the... tools are intended for placing and removing materials in and from the press. Hand feeding tools are not... hazard areas to lubricate material, punches or dies. (e) Inspection, maintenance, and modification...

  4. 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…

  5. 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…

  6. African-American Press Coverage of Clarence Thomas Nomination.

    ERIC Educational Resources Information Center

    Fearn-Banks, Kathleen

    1994-01-01

    Examines pressures facing the African American press by focusing on its coverage of the 1991 nomination of Clarence Thomas to the United States Supreme Court. Discusses the dilemma these newspapers faced in choosing between supporting African Americans and supporting civil rights, with their mixed coverage of the story reflecting this dilemma. (SR)

  7. Democratic Socialism: Toward a Fifth Theory of the Press.

    ERIC Educational Resources Information Center

    Picard, Robert G.

    For more than 25 years, the "four theories" paradigm has been dominant in the study of the relationships among the press, society, and the state. Asserting that the major approaches to such study are the libertarian, social responsibility, authoritarian, and Soviet/communist theories, this paradigm fails to account for economic and social…

  8. 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

  9. 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…

  10. Gemini 8 prime and backup crews during press conference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Gemini 8 prime and backup crews during press conference. Left to right are Astronauts David R. Scott, prime crew pilot; Neil A. Armstrong, prime crew command pilot; Charles Conrad Jr., backup crew command pilot; and Richard F. Gordon Jr., backup crew pilot.

  11. 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…

  12. 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

  13. 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

  14. Relation of Questions and Answers in Kennedy's Press Conferences.

    ERIC Educational Resources Information Center

    Ostman, Ronald E.; And Others

    1981-01-01

    Analyzes the questions posed by reporters and the answers given by President John F. Kennedy in his formal press conferences. Concludes that questions that followed the rules for interviewing set forth by experts produced better answers than those that did not follow rules. (FL)

  15. Attitudes of High School Principals about Press Freedom after Hazelwood.

    ERIC Educational Resources Information Center

    Dickson, Thomas V.

    1989-01-01

    Surveys high school principals in Missouri to examine how they have responded to their new authority over the student press following the Supreme Court's Hazelwood decision. Reports that while principals say that student newspapers are open forums, most also say that they would censor certain types of material. (MM)

  16. 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.

  17. 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

  18. The Suburban Press; First Steps toward an Annotated Bibliography. Suburban Press Research Series No. 16 and 17.

    ERIC Educational Resources Information Center

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

    This bibliography lists journal articles concerning various aspects of the suburban press. Annotated selections, arranged alphabetically according to journal title, are gathered from the following periodicals: "Advertising Age,""Business Week,""Columbia Journalism Review,""Editor and Publisher,""Grassroots Editor,""Journalism…

  19. 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; Rolland, Nicolas; Wagner, Anne-Marie

    2013-04-01

    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 polar regions has been implemented only over recent decades (Pienitz et al., 2004). Hence, to extend in time the climate record, we use a multi-proxy paleolimnological approach to study the sedimentary records preserved in Nettilling Lake located on Baffin Island the largest lake in the Canadian Arctic Archipelago. Nettilling Lake has an area of 5.541 km2 and a maximum depth of 65 m (Oliver, 1964). 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 around 5000 years BP (Jacobs et al., 1997). Nettilling Lake remains a scientific frontier for researchers, mainly due to the inaccessibility of the area and the lack of available data. To date, only one exploratory study by Oliver (1964) has focused on the limnological conditions and bathymetry of the lake, and our research aims at providing deeper insights into the history of paleoenvironmental changes in this remote Arctic region. Biostratigraphical and geochemical analyses were completed on two sediment cores, one from a lagoonal system in the northwestern part of Nettilling Lake and another from the eastern part of the Lake. The sediment cores from the lagoonal system clearly document the marine-lacustrine transition through shifts in paleosalinity inferred from the composition of fossil diatom assemblages. Fossil chironomid larvae first appeared in the record after basin isolation and the establishment of freshwater conditions. Precise

  20. Sensitivity of glacial isostatic adjustment models with shallow low-viscosity earth layers to the ice-load history in relation to the performance of GOCE and GRACE

    NASA Astrophysics Data System (ADS)

    Schotman, H. H. A.; Vermeersen, L. L. A.

    2005-08-01

    The GOCE satellite mission, which is planned by ESA for launch in August 2006, is designed to map the static global gravity field with centimeter accuracy in geoid height at 100 km or better resolution. Such a global high resolution gravity field might be able to constrain properties of shallow low-viscosity zones (LVZs) using glacial isostatic adjustment (GIA) models. In (L.L.A. Vermeersen, The potential of GOCE in constaining the structure of the crust and lithosphere from post-gracial rebound, Space Sci. Rev. 108 (2003) 105-113.) and (W. van der Wal, H.H.A. Schotman, L.L.A. Vermeersen, Geoid heights due to a crustal low viscosity zone in glacial isostatic adjustment modeling; a sensitivity analysis for GOCE, Geophys. Res. Lett. 31 (2004) 10.1029/2003GL019139.) it is shown that a crustal low-viscosity zone (CLVZ) introduces variations in geoid height up to several decimeters with spatial scales down to hundred kilometers underneath and just outside formerly glaciated areas. In (W. van der Wal, H.H.A. Schotman, L.L.A. Vermeersen, Geoid heights due to a crustal low viscosity zone in glacial isostatic adjustment modeling; a sensitivity analysis for GOCE, Geophys. Res. Lett. 31 (2004) 10.1029/2003GL019139.) it is shown that the response is sensitive to both changes in the properties of the CLVZ and the Late Pleistocene ice-load history. In this study we quantify the sensitivity to ice-load history, and investigate the effect of an asthenospheric low-viscosity zone (ALVZ) just below the lithosphere. We show, using spherical harmonic degree amplitudes, that GOCE is predicted to be sensitive to differences in the load history up to degree 130 for a CLVZ and degree 70 for an ALVZ. The sensitivity of GRACE, using the realized performance over a 111-day period (GGM01S, (B.D. Tapley, S. Bettadpur, M. Watkins, C. Reigber, The gravity recovery and climate experiment: Mission overview and early results, Geophys. Res Lett. 31 (2004) 10.1029/2004GL019920.)) is limited to lower

  1. 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

  2. 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

  3. 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

  4. Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe (Belgium, the Netherlands, Germany, southern North Sea)

    NASA Astrophysics Data System (ADS)

    Vink, Annemiek; Steffen, Holger; Reinhardt, Lutz; Kaufmann, Georg

    2007-12-01

    A comprehensive observational database of Holocene relative sea-level (RSL) index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time-depth scale. RSL rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca 7.5 m relative to Belgium since 8 cal. ka BP along the northwest German coast. The subsidence is at least in part related to the Post-Glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earth's mantle underneath NW Europe (lithosphere thickness, upper- and lower-mantle viscosity), and conversely to predict RSL in regions where we have only few observational data (e.g. in the southern North Sea). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the Last Ice Age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled RSL data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow, WNW-ESE trending band connecting the German federal state of Lower Saxony with the Dogger Bank area in the southern North Sea. Identification of the effects of local-scale factors such as past changes in tidal range or tectonic

  5. Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe and the southern North Sea: Observational and model results

    NASA Astrophysics Data System (ADS)

    Vink, A.; Steffen, H.; Reinhardt, L.; Frechen, M.; Kaufmann, G.

    2009-04-01

    A thorough understanding of the causes and effects of differential relative sea-level (RSL) rise in the southern North Sea region since the end of the Last Glacial Maximum is important to help predict future morphological development along the intensively utilised northwest European coastal zone. In this study, a comprehensive observational database of Holocene RSL index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time-depth scale. RSL-rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca. 7.5 m relative to Belgium since 8 cal. kyr BP along the northwest German coast. The subsidence is at least in part related to the post-glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earths mantle underneath NW Europe (lithosphere thickness, upper and lower mantle viscosity), and conversely to predict RSL and reconstruct palaeoshorelines in regions where we have only few observational data (e.g. in the German Bight). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the last ice age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled

  6. 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

  7. After the Highwayman: Syntax and Successful Placement of Press Releases in Newspapers.

    ERIC Educational Resources Information Center

    Walters, Timothy N.; And Others

    1994-01-01

    Compares the grammatical structure of original press releases with the resultant placements in daily newspapers. Finds that, in their use of press releases, journalists almost always have to make them simpler, shorter, easier to read, and less passive. (SR)

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Using SPC for the dry-pressing of beryllia parts

    SciTech Connect

    Sepulveda, J.L.; Jech, D.E.; Ferguson, G. )

    1994-01-01

    Recent advances in the development of high-power electronic devices require the use of materials which are both good electrical insulators and good thermal conductors. Beryllia ceramics exhibit excellent electrical and thermal management performance. Production of beryllia parts requires consistent, ceramic-grade powders and reliable fabrication processes. The extractive process, dry-pressing fabrication process, and the application of statistical process control techniques are reviewed. The important mechanical, thermal, and electrical properties of beryllia are compared to other common ceramic materials.

  20. Regional glacial-isostatic adjustment in Antarctica inferred from combining spaceborne geodetic observations (ESA-STSE CryoSat+ Project REGINA)

    NASA Astrophysics Data System (ADS)

    Sasgen, Ingo; Martin, Alba; Horvath, Alexander; Klemann, Volker; Petrie, Elizabeth; Wouters, Bert; Horwath, Martin; Pail, Roland; Bamber, Jonathan; Clarke, Peter J.; Konrad, Hannes; Drinwater, Mark

    2016-04-01

    A major uncertainty in determining the mass balance of the Antarctic ice sheet from satellite gravimetry, and to a lesser extent altimetry, measurements is the poorly known correction for the glacial isostatic adjustment (GIA) of the solid Earth. Although much progress has been made in consistently modelling ice-sheet evolution and related bedrock deformation, predictions of GIA remain ambiguous due to the sparsity of geodetic and geological constraints. Here, we present an improved geodetic GIA estimate based on GRACE, Envisat/ICESat/CryoSat-2 and GPS measurements. Using viscoelastic response functions of the radial displacement and gravity field change to a disc load forcing, we estimate GIA based on multiple space-geodetic observations, making use of their different sensitivities to surface and solid Earth processes. The approach allows us to consider a laterally varying lithosphere thickness and mantle viscosity in Antarctica, and particularly investigate the effect of a low-viscosity asthenosphere and a ductile layer in the elastic lithosphere in West Antarctica. We compare our GIA estimate with published estimates and results from numerical modelling, and evaluate its impact on the determination of ice-mass balance in Antarctica from GRACE and CryoSat-2. The results presented are the final results of the Support To Science Element Project REGINA and its Supplementary Study of the European Space Agency, www.regina-science.eu.

  1. The Holocene shore displacement of Gästrikland, eastern Sweden: a contribution to the knowledge of Scandinavian glacio-isostatic uplift

    NASA Astrophysics Data System (ADS)

    Berglund, Mikael

    2005-09-01

    The shore displacement in Gästrikland, east-central Sweden, has been investigated by means of AMS radiocarbon dating of sediment cores from isolated basins. Twenty dates from 11 sites are presented. Pollen and diatom analyses, and archive material from the Geological Survey of Sweden, have been used to identify isolation intervals in the cores and as chronological support to the 14C dates. An important pollen stratigraphical time-marker is a distinct mid-Holocene increase in Tilia. For the mid-Holocene, pollen stratigraphy is used rather than the 14C dates for the age determination. The deglaciation of Gästrikland, according to the new 14C dates, took place ca. 11 000 cal. yr BP (ca. 9500 14C yr BP). Through the Holocene the shore displacement is regressive. The regression was initially rapid (on average ca. 3.5 m per 100 yr 11 000-7500 cal. yr BP, probably much more rapid at the earliest stage), then slowed down considerably and was from ca. 5000 cal. yr BP (probably already from 7000 cal. yr BP) relatively constant, ca. 0.8-0.9m per 100yr. There are important differences between the shore level curve from Gästrikland and curves from other areas, indicating some irregularities in the regional glacio-isostatic rebound. Copyright

  2. Filter press plugging in zinc plant purification circuits

    NASA Astrophysics Data System (ADS)

    Chen, T. T.; Dutrizac, J. E.

    2003-04-01

    Mineralogical studies were carried out to identify the causes of filter press plugging in two zinc plant purification circuits. In the first circuit, Kraft paper covers were used over the filter cloths. An extensive layer of basic zinc sulfate, Zn4(SO4)(OH)6.xH2O or Zn5(SO4)2)(OH)6.xH2O, precipitated on the surface of the Kraft paper and within the pores of the paper. In the second circuit, woven polypropylene cloth was used in the first-stage filter presses. The cloth was extensively covered by basic zinc sulfate, which also filled the relatively large pores in this type of material. An unwoven polypropylene cloth was used in the second-stage filter presses of this circuit. The significantly finer pores in this type of cloth appeared to be plugged by major amounts of zinc sulfate, ZnSO4.xH2O, that presumably crystallized because of the temperature-concentration conditions prevailing in that part of the circuit.

  3. Gas loading apparatus for the Paris-Edinburgh press

    SciTech Connect

    Bocian, A.; Kamenev, K. V.; Bull, C. L.; Hamidov, H.; Loveday, J. S.; Nelmes, R. J.

    2010-09-15

    We describe the design and operation of an apparatus for loading gases into the sample volume of the Paris-Edinburgh press at room temperature and high pressure. The system can be used for studies of samples loaded as pure or mixed gases as well as for loading gases as pressure-transmitting media in neutron-scattering experiments. The apparatus consists of a high-pressure vessel and an anvil holder with a clamp mechanism. The vessel, designed to operate at gas pressures of up to 150 MPa, is used for applying the load onto the anvils located inside the clamp. This initial load is sufficient for sealing the pressurized gas inside the sample containing gasket. The clamp containing the anvils and the sample is then transferred into the Paris-Edinburgh press by which further load can be applied to the sample. The clamp has apertures for scattered neutron beams and remains in the press for the duration of the experiment. The performance of the gas loading system is illustrated with the results of neutron-diffraction experiments on compressed nitrogen.

  4. Response Induction during the Acquisition and Maintenance of Lever Pressing with Delayed Reinforcement

    ERIC Educational Resources Information Center

    Escobar, Rogelio; Bruner, Carlos A.

    2007-01-01

    The acquisition of lever pressing by rats and the occurrence of unreinforced presses at a location different from that of the reinforced response were studied using different delays of reinforcement. An experimental chamber containing seven identical adjoining levers was used. Only presses on the central (operative) lever produced food pellets.…

  5. 22 CFR 9b.5 - Temporary Department of State press building passes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Temporary Department of State press building passes. 9b.5 Section 9b.5 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS GOVERNING DEPARTMENT OF STATE PRESS BUILDING PASSES § 9b.5 Temporary Department of State press building passes. A...

  6. 22 CFR 9b.2 - Press correspondents employed by United States media organizations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... media organizations. 9b.2 Section 9b.2 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS... media organizations. In order to obtain a Department of State press building pass, press correspondents employed by United States media organizations must: (a) Present to the Office of Press...

  7. 22 CFR 9b.2 - Press correspondents employed by United States media organizations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... media organizations. 9b.2 Section 9b.2 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS... media organizations. In order to obtain a Department of State press building pass, press correspondents employed by United States media organizations must: (a) Present to the Office of Press...

  8. 22 CFR 9b.2 - Press correspondents employed by United States media organizations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... media organizations. 9b.2 Section 9b.2 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS... media organizations. In order to obtain a Department of State press building pass, press correspondents employed by United States media organizations must: (a) Present to the Office of Press...

  9. 22 CFR 9b.2 - Press correspondents employed by United States media organizations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... media organizations. 9b.2 Section 9b.2 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS... media organizations. In order to obtain a Department of State press building pass, press correspondents employed by United States media organizations must: (a) Present to the Office of Press...

  10. 22 CFR 9b.2 - Press correspondents employed by United States media organizations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... media organizations. 9b.2 Section 9b.2 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS... media organizations. In order to obtain a Department of State press building pass, press correspondents employed by United States media organizations must: (a) Present to the Office of Press...

  11. The Hutchins Commission, The Press and the Responsibility Concept. Journalism Monographs No. 49.

    ERIC Educational Resources Information Center

    Blanchard, Margaret A.

    This monograph details several of the factors which brought about the publication, in 1947, of "A Free and Responsible Press," the report of the Hutchins Commission on Freedom of the Press. The commission's report gave the press a face-saving way of responding to the criticism which was leveled at the economic structure of newspaper operations and…

  12. Freedom of the Press in Europe, 1815-1914. Journalism Monographs Number Eighty.

    ERIC Educational Resources Information Center

    Goldstein, Robert J.

    In 19th century Europe, the dominant classes detested the idea of a free press, seeing it as a middle and lower class weapon. Although repression of the press in Europe existed long before the 19th century, at this time techniques of press repression fell into two major categories: (1) direct--licensing, prior censorship, and post-publication…

  13. 40 CFR 180.1291 - Cold pressed neem oil; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Cold pressed neem oil; exemption from... FOOD Exemptions From Tolerances § 180.1291 Cold pressed neem oil; exemption from the requirement of a tolerance. Residues of the biochemical pesticide cold pressed neem oil are exempt from the requirement of...

  14. Ideals, Interests and Civil Liberty: The Colonial Press and Freedom, 1735-76

    ERIC Educational Resources Information Center

    Rivera, Clark

    1978-01-01

    An analysis of the colonial American press shows that, although it was not a free press as people now conceive of one, freedom of expression was in general less restricted than in other contemporary cultures, and the press did foster and utilize conceptions of freedom that foreshadowed those of today. (GW)

  15. The Partisan Press in Hong Kong: Between British Colonial Rule and Chinese Politics.

    ERIC Educational Resources Information Center

    Lee, Chin-Chuan

    The aim of this paper is to provide a socio-historical perspective on the continuity and change of the Chinese press in Hong Kong. Divided into four sections, the paper examines (1) the partisan press structure as a microcosm of China's interparty struggle; (2) the rise of the market-oriented centrist press since 1970 as a result of Hong Kong's…

  16. 40 CFR 180.1291 - Cold pressed neem oil; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Cold pressed neem oil; exemption from... FOOD Exemptions From Tolerances § 180.1291 Cold pressed neem oil; exemption from the requirement of a tolerance. Residues of the biochemical pesticide cold pressed neem oil are exempt from the requirement of...

  17. Black Press Commentary on the Japanese Internment during World War II.

    ERIC Educational Resources Information Center

    Jeter, James Phillip

    A study examined contemporary reactions of the Black American press to the relocation and internment of the Japanese and Japanese Americans during World War II. Noting that the Black American press has been an activist press since its inception in 1827, it was hypothesized that Black newspapers would editorialize against the internment of Japanese…

  18. The Egyptian Press: An Historical View of Its Importance in Political Movements.

    ERIC Educational Resources Information Center

    Tyler, John

    This report traces the development of the Egyptian press, from its origin with the arrival of the first printing press in 1789 to the present free press policies of Anwar Sadat. Because political struggle and social reform have accompanied the educational and cultural progress of Egypt, the news publications have traditionally been utilitarian.…

  19. Pronouncements and Denunciations: An Analysis of State Press Association Ethics Codes from the 1920s.

    ERIC Educational Resources Information Center

    Cronin, Mary M.; McPherson, James B.

    1995-01-01

    Discusses how four situational concerns (the rise of press agents, the fallout from World War I propaganda, sensationalism's resurgence, and editorial independence) contributed to a noticeable decline of the public's trust in the press. Shows how, as a result, 12 state press association ethics codes from the 1920s consistently emphasized the…

  20. 25 CFR 307.5 - Hand seal press and certificates to be furnished.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Hand seal press and certificates to be furnished. 307.5... FABRICS; USE OF GOVERNMENT CERTIFICATE OF GENUINENESS § 307.5 Hand seal press and certificates to be... § 307.6 one hand seal press and a supply of blank Government certificates, which shall be used only...