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Sample records for african mcs anvils

  1. Leading and Trailing Anvil Clouds of West African Squall Lines

    NASA Technical Reports Server (NTRS)

    Centrone, Jasmine; Houze, Robert A.

    2011-01-01

    The anvil clouds of tropical squall-line systems over West Africa have been examined using cloud radar data and divided into those that appear ahead of the leading convective line and those on the trailing side of the system. The leading anvils are generally higher in altitude than the trailing anvil, likely because the hydrometeors in the leading anvil are directly connected to the convective updraft, while the trailing anvil generally extends out of the lower-topped stratiform precipitation region. When the anvils are subdivided into thick, medium, and thin portions, the thick leading anvil is seen to have systematically higher reflectivity than the thick trailing anvil, suggesting that the leading anvil contains numerous larger ice particles owing to its direct connection to the convective region. As the leading anvil ages and thins, it retains its top. The leading anvil appears to add hydrometeors at the highest altitudes, while the trailing anvil is able to moisten a deep layer of the atmosphere.

  2. Leading and Trailing Anvil Clouds of West African Squall Lines

    NASA Technical Reports Server (NTRS)

    Centrone, Jasmine; Houze, Robert A.

    2011-01-01

    The anvil clouds of tropical squall-line systems over West Africa have been examined using cloud radar data and divided into those that appear ahead of the leading convective line and those on the trailing side of the system. The leading anvils are generally higher in altitude than the trailing anvil, likely because the hydrometeors in the leading anvil are directly connected to the convective updraft, while the trailing anvil generally extends out of the lower-topped stratiform precipitation region. When the anvils are subdivided into thick, medium, and thin portions, the thick leading anvil is seen to have systematically higher reflectivity than the thick trailing anvil, suggesting that the leading anvil contains numerous larger ice particles owing to its direct connection to the convective region. As the leading anvil ages and thins, it retains its top. The leading anvil appears to add hydrometeors at the highest altitudes, while the trailing anvil is able to moisten a deep layer of the atmosphere.

  3. Anvil Clouds of Tropical Mesoscale Convective Systems in Monsoon Regions

    NASA Technical Reports Server (NTRS)

    Cetrone, J.; Houze, R. A., Jr.

    2009-01-01

    The anvil clouds of tropical mesoscale convective systems (MCSs) in West Africa, the Maritime Continent and the Bay of Bengal have been examined with TRMM and CloudSat satellite data and ARM ground-based radar observations. The anvils spreading out from the precipitating cores of MCSs are subdivided into thick, medium and thin portions. The thick portions of anvils show distinct differences from one climatological regime to another. In their upper portions, the thick anvils of West Africa MCSs have a broad, flat histogram of reflectivity, and a maximum of reflectivity in their lower portions. The reflectivity histogram of the Bay of Bengal thick anvils has a sharply peaked distribution of reflectivity at all altitudes with modal values that increase monotonically downward. The reflectivity histogram of the Maritime Continent thick anvils is intermediate between that of the West Africa and Bay of Bengal anvils, consistent with the fact this region comprises a mix of land and ocean influences. It is suggested that the difference between the statistics of the continental and oceanic anvils is related to some combination of two factors: (1) the West African anvils tend to be closely tied to the convective regions of MCSs while the oceanic anvils are more likely to be extending outward from large stratiform precipitation areas of MCSs, and (2) the West African MCSs result from greater buoyancy, so that the convective cells are more likely to produce graupel particles and detrain them into anvils

  4. Improved Anvil Forecasting

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.

    2000-01-01

    This report describes the outcome of Phase 1 of the AMU's Improved Anvil Forecasting task. Forecasters in the 45th Weather Squadron and the Spaceflight Meteorology Group have found that anvil forecasting is a difficult task when predicting LCC and FR violations. The purpose of this task is to determine the technical feasibility of creating an anvil-forecasting tool. Work on this study was separated into three steps: literature search, forecaster discussions, and determination of technical feasibility. The literature search revealed no existing anvil-forecasting techniques. However, there appears to be growing interest in anvils in recent years. If this interest continues to grow, more information will be available to aid in developing a reliable anvil-forecasting tool. The forecaster discussion step revealed an array of methods on how better forecasting techniques could be developed. The forecasters have ideas based on sound meteorological principles and personal experience in forecasting and analyzing anvils. Based on the information gathered in the discussions with the forecasters, the conclusion of this report is that it is technically feasible at this time to develop an anvil forecasting technique that will significantly contribute to the confidence in anvil forecasts.

  5. Diamond anvil technology

    NASA Astrophysics Data System (ADS)

    Seal, Michael

    This paper is largely a review of the techniques used in making diamond anvils and the constraints these put on the shapes of anvil. Techniques available for shaping diamonds include cleaving, sawing, polishing, laser cutting, and bruting. At present the shapes most commonly used for anvils are a modification of the brilliant cut derived from the gem industry, and a design based on an octagonal prism with truncated pyramidal top and base, known as the "Drukker standard design". Diamond orientation and material selection are considered as are future possibilities for the attainment of still higher pressures through modifications of the diamond anvil material or design.

  6. The Munich Coma Scle (MCS).

    PubMed Central

    Brinkmann, R; Von Cramon, D; Schulz, H

    1976-01-01

    The level of coma can be measured by the assessment of changes of behaviour after different intensities of stimulation. Two additive scales (Guttman scales) for susceptibility to stimulation and reactivity were developed, constituting the Munich Coma Scale (MCS). The findings of previous investigations were repeated in a new sample of 67 comatose patients. Implications of the additivity of reactivity are discussed and related to the concept of 'behavioural arousal' advanced in the recent literature. PMID:956865

  7. Advanced Diamond Anvil Techniques (Customized Diamond Anvils)

    SciTech Connect

    Weir, S

    2009-02-11

    A complete set of diamond-based fabrication tools now exists for making a wide range of different types of diamond anvils which are tailored for various high-P applications. Current tools include: CVD diamond deposition (making diamond); Diamond polishing, laser drilling, plasma etching (removal of diamond); and Lithography, 3D laser pantography (patterning features onto diamond); - Metal deposition (putting electrical circuits and metal masks onto diamond). Current applications include the following: Electrical Conductivity; Magnetic Susceptibility; and High-P/High-T. Future applications may include: NMR; Hall Effect; de Haas - Shubnikov (Fermi surface topology); Calorimetry; and thermal conductivity.

  8. Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data

    NASA Technical Reports Server (NTRS)

    Yuan, Jian; Houze, Robert A.

    2010-01-01

    Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-train satellite instruments: Moderate Resolution Imaging Spectroradiometer (MODIS) for cloud-top size and coldness, Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) for rain area size and intensity, and CloudSat for horizontal and vertical dimensions of anvils. The authors distinguish three types of MCSs: small and large separated MCSs and connected MCSs. The latter are MCSs sharing a contiguous rain area. Mapping of the objectively identified MCSs shows patterns of MCSs that are consistent with previous studies of tropical convection, with separated MCSs dominant over Africa and the Amazon regions and connected MCSs favored over the warm pool of the Indian and west Pacific Oceans. By separating the anvil from the raining regions of MCSs, this study leads to quantitative global maps of anvil coverage. These maps are consistent with the MCS analysis, and they lay the foundation for estimating the global radiative effects of anvil clouds. CloudSat radar data show that the modal thickness of MCS anvils is about 4-5 km. Anvils are mostly confined to within 1.5-2 times the equivalent radii of the primary rain areas of the MCSs. Over the warm pool, they may extend out to about 5 times the rain area radii. The warm ocean MCSs tend to have thicker non-raining and lightly raining anvils near the edges

  9. Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data

    NASA Technical Reports Server (NTRS)

    Yuan, Jian; Houze, Robert A.

    2010-01-01

    Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-train satellite instruments: Moderate Resolution Imaging Spectroradiometer (MODIS) for cloud-top size and coldness, Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) for rain area size and intensity, and CloudSat for horizontal and vertical dimensions of anvils. The authors distinguish three types of MCSs: small and large separated MCSs and connected MCSs. The latter are MCSs sharing a contiguous rain area. Mapping of the objectively identified MCSs shows patterns of MCSs that are consistent with previous studies of tropical convection, with separated MCSs dominant over Africa and the Amazon regions and connected MCSs favored over the warm pool of the Indian and west Pacific Oceans. By separating the anvil from the raining regions of MCSs, this study leads to quantitative global maps of anvil coverage. These maps are consistent with the MCS analysis, and they lay the foundation for estimating the global radiative effects of anvil clouds. CloudSat radar data show that the modal thickness of MCS anvils is about 4-5 km. Anvils are mostly confined to within 1.5-2 times the equivalent radii of the primary rain areas of the MCSs. Over the warm pool, they may extend out to about 5 times the rain area radii. The warm ocean MCSs tend to have thicker non-raining and lightly raining anvils near the edges

  10. Diamond Anvil Cell Techniques

    NASA Astrophysics Data System (ADS)

    Piermarini, Gasper J.

    It has often been said that scientific advances are made either in a dramatic and revolutionary way, or, as in the case of the diamond anvil cell (DAC), in a slow and evolutionary manner over a period of several years. For more than 2 decades, commencing in 1958, the DAC developed stepwise from a rather crude qualitative instrument to the sophisticated quantitative research tool it is today, capable of routinely producing sustained static pressures in the multi-megabar range and readily adaptable to numerous scientific measurement techniques because of its optical accessibility, miniature size, and portability.

  11. Cohort profile: UK Millennium Cohort Study (MCS).

    PubMed

    Connelly, Roxanne; Platt, Lucinda

    2014-12-01

    The UK Millennium Cohort Study (MCS) is an observational, multidisciplinary cohort study that was set up to follow the lives of children born at the turn of the new century. The MCS is nationally representative and 18 552 families (18 827 children) were recruited to the cohort in the first sweep. There have currently been five main sweeps of data collection, at ages 9 months and 3, 5, 7 and 11 years. A further sweep of data collection is planned for age 14 years. A range of health-related data have been collected as well as measures concerning child development, cognitive ability and educational attainment. The data also include a wealth of information describing the social, economic and demographic characteristics of the cohort members and their families. In addition, the MCS data have been linked to administrative data resources including health records. The MCS provides a unique and valuable resource for the analysis of health outcomes and health inequalities. The MCS data are freely available to bona fide researchers under standard access conditions via the UK Data Service (http://ukdataservice.ac.uk) and the MCS website provides detailed information on the study (http://www.cls.ioe.ac.uk/mcs).

  12. Physical Confirmation and Mapping of Overlapping Rat Mammary Carcinoma Susceptibility QTLs, Mcs2 and Mcs6

    PubMed Central

    Sanders, Jennifer; Haag, Jill D.; Samuelson, David J.

    2011-01-01

    Only a portion of the estimated heritability of breast cancer susceptibility has been explained by individual loci. Comparative genetic approaches that first use an experimental organism to map susceptibility QTLs are unbiased methods to identify human orthologs to target in human population-based genetic association studies. Here, overlapping rat mammary carcinoma susceptibility (Mcs) predicted QTLs, Mcs6 and Mcs2, were physically confirmed and mapped to identify the human orthologous region. To physically confirm Mcs6 and Mcs2, congenic lines were established using the Wistar-Furth (WF) rat strain, which is susceptible to developing mammary carcinomas, as the recipient (genetic background) and either Wistar-Kyoto (WKy, Mcs6) or Copenhagen (COP, Mcs2), which are resistant, as donor strains. By comparing Mcs phenotypes of WF.WKy congenic lines with distinct segments of WKy chromosome 7 we physically confirmed and mapped Mcs6 to ∼33 Mb between markers D7Rat171 and gUwm64-3. The predicted Mcs2 QTL was also physically confirmed using segments of COP chromosome 7 introgressed into a susceptible WF background. The Mcs6 and Mcs2 overlapping genomic regions contain multiple annotated genes, but none have a clear or well established link to breast cancer susceptibility. Igf1 and Socs2 are two of multiple potential candidate genes in Mcs6. The human genomic region orthologous to rat Mcs6 is on chromosome 12 from base positions 71,270,266 to 105,502,699. This region has not shown a genome-wide significant association to breast cancer risk in pun studies of breast cancer susceptibility. PMID:21625632

  13. Vertical Structures of Anvil Clouds of Tropical Mesoscale Convective Systems Observed by CloudSat

    NASA Technical Reports Server (NTRS)

    Hence, Deanna A.; Houze, Robert A.

    2011-01-01

    A global study of the vertical structures of the clouds of tropical mesoscale convective systems (MCSs) has been carried out with data from the CloudSat Cloud Profiling Radar. Tropical MCSs are found to be dominated by cloud-top heights greater than 10 km. Secondary cloud layers sometimes occur in MCSs, but outside their primary raining cores. The secondary layers have tops at 6 8 and 1 3 km. High-topped clouds extend outward from raining cores of MCSs to form anvil clouds. Closest to the raining cores, the anvils tend to have broader distributions of reflectivity at all levels, with the modal values at higher reflectivity in their lower levels. Portions of anvil clouds far away from the raining core are thin and have narrow frequency distributions of reflectivity at all levels with overall weaker values. This difference likely reflects ice particle fallout and therefore cloud age. Reflectivity histograms of MCS anvil clouds vary little across the tropics, except that (i) in continental MCS anvils, broader distributions of reflectivity occur at the uppermost levels in the portions closest to active raining areas; (ii) the frequency of occurrence of stronger reflectivity in the upper part of anvils decreases faster with increasing distance in continental MCSs; and (iii) narrower-peaked ridges are prominent in reflectivity histograms of thick anvil clouds close to the raining areas of connected MCSs (superclusters). These global results are consistent with observations at ground sites and aircraft data. They present a comprehensive test dataset for models aiming to simulate process-based upper-level cloud structure around the tropics.

  14. Vertical Structures of Anvil Clouds of Tropical Mesoscale Convective Systems Observed by CloudSat

    NASA Technical Reports Server (NTRS)

    Yuan, J.; Houze, R. A., Jr.; Heymsfield, A.

    2011-01-01

    A global study of the vertical structures of the clouds of tropical mesoscale convective systems (MCSs) has been carried out with data from the CloudSat Cloud Profiling Radar. Tropical MCSs are found to be dominated by cloud-top heights greater than 10 km. Secondary cloud layers sometimes occur in MCSs, but outside their primary raining cores. The secondary layers have tops at 6--8 and 1--3 km. High-topped clouds extend outward from raining cores of MCSs to form anvil clouds. Closest to the raining cores, the anvils tend to have broader distributions of reflectivity at all levels, with the modal values at higher reflectivity in their lower levels. Portions of anvil clouds far away from the raining core are thin and have narrow frequency distributions of reflectivity at all levels with overall weaker values. This difference likely reflects ice particle fallout and therefore cloud age. Reflectivity histograms of MCS anvil clouds vary little across the tropics, except that (i) in continental MCS anvils, broader distributions of reflectivity occur at the uppermost levels in the portions closest to active raining areas; (ii) the frequency of occurrence of stronger reflectivity in the upper part of anvils decreases faster with increasing distance in continental MCSs; and (iii) narrower-peaked ridges are prominent in reflectivity histograms of thick anvil clouds close to the raining areas of connected MCSs (superclusters). These global results are consistent with observations at ground sites and aircraft data. They present a comprehensive test dataset for models aiming to simulate process-based upper-level cloud structure around the tropics.

  15. Vertical Structures of Anvil Clouds of Tropical Mesoscale Convective Systems Observed by CloudSat

    NASA Technical Reports Server (NTRS)

    Yuan, J.; Houze, R. A., Jr.; Heymsfield, A.

    2011-01-01

    A global study of the vertical structures of the clouds of tropical mesoscale convective systems (MCSs) has been carried out with data from the CloudSat Cloud Profiling Radar. Tropical MCSs are found to be dominated by cloud-top heights greater than 10 km. Secondary cloud layers sometimes occur in MCSs, but outside their primary raining cores. The secondary layers have tops at 6--8 and 1--3 km. High-topped clouds extend outward from raining cores of MCSs to form anvil clouds. Closest to the raining cores, the anvils tend to have broader distributions of reflectivity at all levels, with the modal values at higher reflectivity in their lower levels. Portions of anvil clouds far away from the raining core are thin and have narrow frequency distributions of reflectivity at all levels with overall weaker values. This difference likely reflects ice particle fallout and therefore cloud age. Reflectivity histograms of MCS anvil clouds vary little across the tropics, except that (i) in continental MCS anvils, broader distributions of reflectivity occur at the uppermost levels in the portions closest to active raining areas; (ii) the frequency of occurrence of stronger reflectivity in the upper part of anvils decreases faster with increasing distance in continental MCSs; and (iii) narrower-peaked ridges are prominent in reflectivity histograms of thick anvil clouds close to the raining areas of connected MCSs (superclusters). These global results are consistent with observations at ground sites and aircraft data. They present a comprehensive test dataset for models aiming to simulate process-based upper-level cloud structure around the tropics.

  16. Vertical Structures of Anvil Clouds of Tropical Mesoscale Convective Systems Observed by CloudSat

    NASA Technical Reports Server (NTRS)

    Hence, Deanna A.; Houze, Robert A.

    2011-01-01

    A global study of the vertical structures of the clouds of tropical mesoscale convective systems (MCSs) has been carried out with data from the CloudSat Cloud Profiling Radar. Tropical MCSs are found to be dominated by cloud-top heights greater than 10 km. Secondary cloud layers sometimes occur in MCSs, but outside their primary raining cores. The secondary layers have tops at 6 8 and 1 3 km. High-topped clouds extend outward from raining cores of MCSs to form anvil clouds. Closest to the raining cores, the anvils tend to have broader distributions of reflectivity at all levels, with the modal values at higher reflectivity in their lower levels. Portions of anvil clouds far away from the raining core are thin and have narrow frequency distributions of reflectivity at all levels with overall weaker values. This difference likely reflects ice particle fallout and therefore cloud age. Reflectivity histograms of MCS anvil clouds vary little across the tropics, except that (i) in continental MCS anvils, broader distributions of reflectivity occur at the uppermost levels in the portions closest to active raining areas; (ii) the frequency of occurrence of stronger reflectivity in the upper part of anvils decreases faster with increasing distance in continental MCSs; and (iii) narrower-peaked ridges are prominent in reflectivity histograms of thick anvil clouds close to the raining areas of connected MCSs (superclusters). These global results are consistent with observations at ground sites and aircraft data. They present a comprehensive test dataset for models aiming to simulate process-based upper-level cloud structure around the tropics.

  17. Anvil for Flaring PCB Guide Pins

    NASA Technical Reports Server (NTRS)

    Winn, E.; Turner, R.

    1985-01-01

    Spring-loaded anvil results in fewer fractured pins. New anvil for flaring guide pins in printed-circuit boards absorbs approximately 80 percent of press force. As result fewer pins damaged, and work output of flaring press greatly increased.

  18. Raman Lidar Observations of a MCS in the frame of the Convective and Orographically-induced Precipitation Study

    NASA Astrophysics Data System (ADS)

    Di Girolamo, Paolo; Bhawar, Rohini; Summa, Donato; Di Iorio, Tatiana; Demoz, Belay B.

    2009-03-01

    The Raman lidar system BASIL was deployed in Achern (Supersite R, Lat: 48.64° N, Long: 8.06° E, Elev.: 140 m) in the frame of the Convective and Orographically-induced Precipitation Study. On 20 July 2007 a frontal zone passed over the COPS region, with a Mesoscale Convective System (MCS) imbedded in it. BASIL was operated continuously during this day, providing measurements of temperature, water vapour, particle backscattering coefficient at 355, 532 and 1064 nm, particle extinction coefficient at 355 and 532 nm and particle depolarization at 355 and 532 nm. The thunderstorm approaching determined the lowering of the anvil clouds, which is clearly visible in the lidar data. A cloud deck is present at 2 km, which represents a mid-level outflow from the thunderstorm/MCS. The mid-level outflow spits out hydrometeor-debris (mostly virga) and it is recycled back into it. The MCS modified the environment at 1.6-2.5 km levels directly (outflow) and the lower levels through the virga/precipitation. Wave structures were observed in the particle backscatter data. The wave activity seems to be a reflection of the shear that is produced by the MCS and the inflow environmental wind. Measurements in terms of particle backscatter and water vapour mixing ratio are discussed to illustrate the above phenomena.

  19. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, William C.

    1988-01-01

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached.

  20. Double bevel construction of a diamond anvil

    DOEpatents

    Moss, W.C.

    1988-10-11

    A double or multiple bevel culet geometry is used on a diamond anvil in a high pressure cell apparatus to provide increased sample pressure and stability for a given force applied to the diamond tables. Double or multiple bevel culet geometries can also be used for sapphire or other hard crystal anvils. Pressures up to and above 5 Megabars can be reached. 8 figs.

  1. Multiple Chemical Sensitivity (MCS) - Scientific and Public-Health Aspects

    PubMed Central

    Schwenk, Michael

    2004-01-01

    Multiple Chemical Sensitivity (MCS) is a phenomenon which the ENT-doctor should be familiar with. It has its roots in the description of a syndrome in 1987. A worker spilled chemicals at his workplace and from then on he reacted highly sensitive to chemicals. Today, there are many people who explain their complaints with self-suspected MCS. Various pathopysiological models have been proposed, including toxicological, immunological or behaviorial models. But no-one could be proved so far. Since controlled provocation tests have also provided unclear results, an increasing number of doctors assumes today, that MCS reflects a psychic condition. In 1996, an expert team of the WHO has suggested the renaming of MCS to "idiopathic environmental illness" (IEI). However, other doctors still assume a chemical cause. Since there are neither straightforward diagnostic methods to proof MCS, nor reliable therapeutic concepts, treatment of MCS-patients is usually difficult. The MCS-debate (somatic vs psychic causes) seems to reflect the dilemma of the medical profession today, that somatic disorders of known origin can be well treated, whereas the increasing number of psychosomatic/ somatoform disorders is often resistant to medical help. The ENT-doctor should pay attention to changes of the nasal mucous membrane, nasal resistance and the sense of smell. Moreover he should know about the peculiarities of MCS-patients. The manuscript describes the present knowledge and state of discussion with special regard to the situation in Germany. PMID:22073047

  2. Electrical structure in two thunderstorm anvil clouds

    NASA Technical Reports Server (NTRS)

    Marshall, Thomas C.; Rust, W. David; Winn, William P.; Gilbert, Kenneth E.

    1989-01-01

    Electrical structures in two thunderstorm anvil clouds (or 'anvils'), one in New Mexico, the other in Oklahoma, were investigated, using measurements of electric field by balloon-carried instruments and a one-dimensional model to calculate the time and spatial variations of electrical parameters in the clear air below the anvil. The electric field soundings through the two thunderstorm anvils showed similar charge structures; namely, negatively charged screening layers on the top and the bottom surfaces, a layer of positive charge in the interior, and one or two layers of zero charge. It is suggested that the positive charge originated in the main positive charge region normally found at high altitudes in the core of thunderclouds, and the negatively charged layers probably formed as screening layers, resulting from the discontinuity in the electrical conductivity at the cloud boundaries.

  3. Mechanisms Underlying the Breast Cancer Susceptibility Locus Mcs5a

    DTIC Science & Technology

    2010-07-01

    Mcs5a2) down regulates the expression of the Fbxo10 gene in the T cells and that this reduced expression is associated with reduced mammary tumor...in primary T cells is conserved between rat and human. We demonstrate that the function of the non-coding Mcs5a locus likely is repressive gene ...regulation. We present a model that begins to explain how the Fbxo10 gene could be regulated in T cells. 15. SUBJECT TERMS mammary carcinogenesis

  4. 16 CFR Figures 11, 12 and 13 to... - Hemispherical Anvil and Curbstone Anvil

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Hemispherical Anvil and Curbstone Anvil 11, Figures 11, 12 and 13 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Figs. 11, 12, 13 Figures...

  5. 16 CFR Figures 11, 12 and 13 to... - Hemispherical Anvil and Curbstone Anvil

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Hemispherical Anvil and Curbstone Anvil 11, Figures 11, 12 and 13 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Figs. 11, 12, 13 Figures...

  6. 16 CFR Figures 11, 12 and 13 to... - Hemispherical Anvil and Curbstone Anvil

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Hemispherical Anvil and Curbstone Anvil 11, Figures 11, 12 and 13 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Figs. 11, 12, 13 Figures...

  7. 16 CFR Figures 11, 12 and 13 to... - Hemispherical Anvil and Curbstone Anvil

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Hemispherical Anvil and Curbstone Anvil 11, Figures 11, 12 and 13 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Figs. 11, 12, 13 Figures...

  8. 16 CFR Figures 11, 12 and 13 to... - Hemispherical Anvil and Curbstone Anvil

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Hemispherical Anvil and Curbstone Anvil 11, Figures 11, 12 and 13 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Figs. 11, 12, 13 Figures...

  9. Forced and Traveling Waves in MRO MCS Atmospheric Temperature Retrievals

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.; Wilson, R.; Kass, D.; Schofield, J. T.; Kleinboehl, A.

    2010-12-01

    We examine the 2 martian years worth of MRO MCS data to reveal the forced (stationary wave and thermal tides) and traveling waves in the martian atmosphere. This analysis is based on the same tools used in Banfield et al 2003, & 2004 in the analysis of MGS TES nadir data and Banfield et al (submitted 2010) MGS TES limb retrievals. In particular, we will characterize interannual variation in the MRO MCS data itself between its two years, as well as differences where spatial coverage is shared with MGS TES results from previous years. We will also identify new details of the atmospheric behavior with the extended vertical coverage and better vertical resolution afforded by the dedicated limb-scanning nature of MRO MCS. Among other time-varying phenomena in the martian atmosphere, we will present the MRO MCS observations of long period traveling waves (~30 sols) in the northern winter hemisphere and at high altitude into the tropics where it was only poorly observed by MGS TES. We will compare the MRO MCS results with MGS TES results, as well as with GCM results where appropriate to extract as complete an understanding of the phenomena revealed as possible.

  10. MCS-18, a novel natural plant product prevents autoimmune diabetes.

    PubMed

    Seifarth, Christian; Littmann, Leonie; Resheq, Yazid; Rössner, Susanne; Goldwich, Andreas; Pangratz, Nadine; Kerek, Franz; Steinkasserer, Alexander; Zinser, Elisabeth

    2011-09-30

    There is still a vital need for new therapies in order to prevent or treat type I diabetes. In this respect, we report that MCS-18 a novel natural product isolated from the plant Helleborus purpurascens (i.e. Christmas rose) is able to increase diabetes free survival using the NOD-mouse model, which is accompanied with a diminished IFN-γ secretion of splenocytes. In the animal group which has been treated with MCS-18 during week 8 and week 12 of age 70% of the animals showed a diabetes free survival at week 30, whereas in contrast in the untreated animals less than 10% were free of diabetes. MCS-18 treatment significantly reduced islet T-cell infiltrates as well as the rate of T-cell proliferation. Periinsular infiltrates in the MCS-18 treated animals showed a significantly enhanced number of Foxp3(+) CD25(+) T cells, indicating the increased presence of regulatory T cells. These studies show that MCS-18 exerts an efficient immunosuppressive activity with remarkable potential for the therapy of diseases characterized by pathological over-activation of the immune system.

  11. Thermodynamic control of anvil cloud amount

    NASA Astrophysics Data System (ADS)

    Bony, Sandrine; Stevens, Bjorn; Coppin, David; Becker, Tobias; Reed, Kevin A.; Voigt, Aiko; Medeiros, Brian

    2016-08-01

    General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative-convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.

  12. Thermodynamic control of anvil cloud amount.

    PubMed

    Bony, Sandrine; Stevens, Bjorn; Coppin, David; Becker, Tobias; Reed, Kevin A; Voigt, Aiko; Medeiros, Brian

    2016-08-09

    General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative-convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.

  13. Introduction to the MCS. Visual Media Learning Guide.

    ERIC Educational Resources Information Center

    Spokane Falls Community Coll., WA.

    This student learning guide is designed to introduce graphics arts students t the MCS (Modular Composition System) compugraphic typesetting system. Addressed in the individual units of the competency-based guide are the following tasks: programming the compugraphic typesetting system, creating a new file and editing a file, operating a…

  14. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  15. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  16. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  17. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  18. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  19. Combining Research Approaches: The Anvil Writers Revisited.

    ERIC Educational Resources Information Center

    Sanders, Keith P.; Morris, Daniel N.

    1990-01-01

    Conjoins Q methodology with the interviewing techniques of the oral historian in a study of eight surviving contributors to "The Anvil," a midwestern proletarian magazine of the 1920s and 1930s. Finds four factors, labeled as the patron, the revolutionary artist, the Jack Conroy factor, and the humanist. Discusses the limitations and advantages of…

  20. Combining Research Approaches: The Anvil Writers Revisited.

    ERIC Educational Resources Information Center

    Sanders, Keith P.; Morris, Daniel N.

    1990-01-01

    Conjoins Q methodology with the interviewing techniques of the oral historian in a study of eight surviving contributors to "The Anvil," a midwestern proletarian magazine of the 1920s and 1930s. Finds four factors, labeled as the patron, the revolutionary artist, the Jack Conroy factor, and the humanist. Discusses the limitations and advantages of…

  1. Multiple chemical sensitivity syndrome (MCS)--suggestions for an extension of the U.S. MCS-case definition.

    PubMed

    Lacour, Michael; Zunder, Thomas; Schmidtke, Klaus; Vaith, Peter; Scheidt, Carl

    2005-01-01

    To validate and extend the US case definition for the Multiple Chemical Sensitivity Syndrome (MCS) from 1999 by a systematic literature-review. MEDLINE-research from 1997 to August 2003, research in the Cochrane-Library in August 2003, earlier reviews since 1997. Headings and abstracts were screened by one reviewer. All references dealing with multiple chemical sensitivities (MCS) which covered topics of interest such as symptom-profiles, differential diagnostic procedures, etc. were included in the analysis. Topic-specific data extraction and synthesis was done by one reviewer. Data interpretation was discussed by all other authors. Out of 1429 references 36 publications proved to be suitable for the review. The results can be summarized as follows: exposure-related symptoms associated with self-reported multiple chemical sensitivities can be divided into non-specific complaints of the central nervous system--CNS (main characteristics) and functional disturbances in other organ systems (optional complaints). There is a significant overlap of MCS, CFS and fibromyalgie. At present no standards for a diagnostic procedure based on the criteria outlined above are existing MCS should only be diagnosed in patients who are mainly suffering from exposure-related non-specific complaints of the Central nervous system. The suggested diagnostic procedure follows the guidelines for CFS which are extended by diagnostic clarification of functional disturbances in other organ systems.

  2. Fine tuning GPS clock estimation in the MCS

    NASA Technical Reports Server (NTRS)

    Hutsell, Steven T.

    1995-01-01

    With the completion of a 24 operational satellite constellation, GPS is fast approaching the critical milestone, Full Operational Capability (FOC). Although GPS is well capable of providing the timing accuracy and stability figures required by system specifications, the GPS community will continue to strive for further improvements in performance. The GPS Master Control Station (MCS) recently demonstrated that timing improvements are always composite Clock, and hence, Kalman Filter state estimation, providing a small improvement to user accuracy.

  3. MCS precipitation and downburst intensity response to increased aerosol concentrations

    NASA Astrophysics Data System (ADS)

    Clavner, M.; Cotton, W. R.; van den Heever, S. C.

    2015-12-01

    Mesoscale convective systems (MCSs) are important contributors to rainfall in the High Plains of the United States as well as producers of severe weather such as hail, tornados and straight-line wind events known as derechos. Past studies have shown that changes in aerosol concentrations serving as cloud condensation nuclei (CCN) alter the MCS hydrometeor characteristics which in turn modify precipitation yield, downdraft velocity, cold-pool strength, storm propagation and the potential for severe weather to occur. In this study, the sensitivity of MCS precipitation characteristics and convective downburst velocities associated with a derecho to changes in CCN concentrations were examined by simulating a case study using the Regional Atmospheric Modeling System (RAMS). The case study of the 8 May 2009 "Super-Derecho" MCS was chosen since it produced a swath of widespread wind damage in association with an embedded large-scale bow echo, over a broad region from the High Plains of western Kansas to the foothills of the Appalachians. The sensitivity of the storm to changes in CCN concentrations was examined by conducting a set of three simulations which differed in the initial aerosol concentration based on output from the 3D chemical transport model, GEOS-Chem. Results from this study indicate that while increasing CCN concentrations led to an increase in precipitation rates, the changes to the derecho strength were not linear. A moderate increase in aerosol concentration reduced the derecho strength, while the simulation with the highest aerosol concentrations increased the derecho intensity. These changes are attributed to the impact of enhanced CCN concentration on the production of convective downbursts. An analysis of aerosol loading impacts on these MCS features will be presented.

  4. Relating the Hadamard Variance to MCS Kalman Filter Clock Estimation

    NASA Technical Reports Server (NTRS)

    Hutsell, Steven T.

    1996-01-01

    The Global Positioning System (GPS) Master Control Station (MCS) currently makes significant use of the Allan Variance. This two-sample variance equation has proven excellent as a handy, understandable tool, both for time domain analysis of GPS cesium frequency standards, and for fine tuning the MCS's state estimation of these atomic clocks. The Allan Variance does not explicitly converge for the nose types of alpha less than or equal to minus 3 and can be greatly affected by frequency drift. Because GPS rubidium frequency standards exhibit non-trivial aging and aging noise characteristics, the basic Allan Variance analysis must be augmented in order to (a) compensate for a dynamic frequency drift, and (b) characterize two additional noise types, specifically alpha = minus 3, and alpha = minus 4. As the GPS program progresses, we will utilize a larger percentage of rubidium frequency standards than ever before. Hence, GPS rubidium clock characterization will require more attention than ever before. The three sample variance, commonly referred to as a renormalized Hadamard Variance, is unaffected by linear frequency drift, converges for alpha is greater than minus 5, and thus has utility for modeling noise in GPS rubidium frequency standards. This paper demonstrates the potential of Hadamard Variance analysis in GPS operations, and presents an equation that relates the Hadamard Variance to the MCS's Kalman filter process noises.

  5. Thermodynamic control of anvil cloud amount

    PubMed Central

    Bony, Sandrine; Stevens, Bjorn; Coppin, David; Becker, Tobias; Reed, Kevin A.; Voigt, Aiko

    2016-01-01

    General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative–convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation. PMID:27412863

  6. Clinical consequences of the EI/MCS "diagnosis": two paths.

    PubMed

    Staudenmayer, H

    1996-08-01

    There are two distinct paths down which patients "diagnosed" with environmental illness/multiple chemical sensitivities (EI/MCS) can travel. Along the first path, beliefs about low-level, multiple chemical sensitivities as the cause of physical and psychological symptoms are instilled and reinforced by a host of factors including toxicogenic speculation, iatrogenic influence mediated by unsubstantiated diagnostic and treatment practices, patient support/advocacy networks, and social contagion. Intrapsychic factors also reinforce this path through the motivational mechanism of factitious malingering, or unconscious primary and secondary gain, mediated through psychological defenses, particularly projection of cause of illness onto the physical environment. The second path involves restructuring distorted beliefs about chemical sensitivities. Explanations of the placebo effect, the physiology of the stress response, and the symptoms of anxiety and panic facilitate the direction of EI/MCS patients onto this path. A decision model is presented to discriminate among toxicogenic and psychogenic explanations of the EI/MCS phenomenon, based on appraisal of reaction and physiologic and cognitive responses during provocation chamber challenges under double-blind, placebo-controlled conditions. These studies have been helpful therapeutically for some patients in selecting the path that leads to wellness. This paper suggests how various therapeutic techniques can be employed with difficult patients. Often, supportive psychotherapy establishes a therapeutic alliance which facilitates cognitive therapy to restructure distorted beliefs. In the process of finding alternative explanations to chemical sensitivities, the etiology of symptoms is related to stressful life events, including childhood experiences which may have disrupted normal personality development and coping capacity. Furthermore, biological and physiological sequelae stemming from early, chronic trauma have been

  7. Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

    DOE PAGES

    Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; ...

    2015-09-01

    Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with evenmore » insulation layers produced by stepped anvils.« less

  8. Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

    SciTech Connect

    Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; Weir, Samuel T.; Falabella, Steve; Lee, Kanani K. M.

    2015-09-01

    Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with even insulation layers produced by stepped anvils.

  9. Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples.

    PubMed

    Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; Weir, Samuel T; Falabella, Steve; Lee, Kanani K M

    2015-09-01

    We describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. The method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with even insulation layers produced by stepped anvils.

  10. An improved hydrothermal diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Li, Jiankang; Bassett, W. A.; Chou, I.-Ming; Ding, Xin; Li, Shenghu; Wang, Xinyan

    2016-05-01

    A new type of HDAC-V hydrothermal diamond anvil cell (HDAC-VT) has been designed to meet the demands of X-ray research including X-Ray Fluorescence, X-ray Absorption Spectroscopy, and small angle X-ray scattering. The earlier version of HDAC-V that offered a large rectangular solid angle used two posts and two driver screws on both sides of a rectangular body. The new version HDAC-VT in a triangular shape has two alternative guide systems, either three posts inserted into bushings suitable for small anvil faces or linear ball bearings suitable for large anvil faces. The HDAC-VT having three driver screws offers the advantage of greater control and stability even though it sacrifices some of the size of solid angle. The greater control allows better sealing of samples, while greater stability results in longer survival for anvils and ceramic parts. This improved design retains several beneficial features of the original HDAC-V as well. These include the small collar that surrounds the heater and sample chamber forming an Ar + H2 gas chamber to protect diamonds and their heating parts from being oxidized. Three linear ball bearings, when used, fit to the three posts prevent seizing that can result from deterioration of lubricant at high temperatures. Positioning the posts and bearings outside of the gas chamber as in HDAC-V also prevents seizing and possible deformation due to overheating. In order to control the heating rate precisely with computer software, we use Linkam T95 and have replaced the Linkam 1400XY heating stage with the HDAC-VT allowing the HDAC to be heated to 950 °C at a rate from 0.01 °C/min to 50 °C/min. We have used the HDAC-VT and Linkam T95 to observe in situ nucleation and growth of zabuyelite in aqueous fluid and to homogenize melt inclusions in quartz from three porphyry deposits in Shanxi, China.

  11. An improved hydrothermal diamond anvil cell.

    PubMed

    Li, Jiankang; Bassett, W A; Chou, I-Ming; Ding, Xin; Li, Shenghu; Wang, Xinyan

    2016-05-01

    A new type of HDAC-V hydrothermal diamond anvil cell (HDAC-VT) has been designed to meet the demands of X-ray research including X-Ray Fluorescence, X-ray Absorption Spectroscopy, and small angle X-ray scattering. The earlier version of HDAC-V that offered a large rectangular solid angle used two posts and two driver screws on both sides of a rectangular body. The new version HDAC-VT in a triangular shape has two alternative guide systems, either three posts inserted into bushings suitable for small anvil faces or linear ball bearings suitable for large anvil faces. The HDAC-VT having three driver screws offers the advantage of greater control and stability even though it sacrifices some of the size of solid angle. The greater control allows better sealing of samples, while greater stability results in longer survival for anvils and ceramic parts. This improved design retains several beneficial features of the original HDAC-V as well. These include the small collar that surrounds the heater and sample chamber forming an Ar + H2 gas chamber to protect diamonds and their heating parts from being oxidized. Three linear ball bearings, when used, fit to the three posts prevent seizing that can result from deterioration of lubricant at high temperatures. Positioning the posts and bearings outside of the gas chamber as in HDAC-V also prevents seizing and possible deformation due to overheating. In order to control the heating rate precisely with computer software, we use Linkam T95 and have replaced the Linkam 1400XY heating stage with the HDAC-VT allowing the HDAC to be heated to 950 °C at a rate from 0.01 °C/min to 50 °C/min. We have used the HDAC-VT and Linkam T95 to observe in situ nucleation and growth of zabuyelite in aqueous fluid and to homogenize melt inclusions in quartz from three porphyry deposits in Shanxi, China.

  12. Anvil Tool in the Advanced Weather Interactive Processing System

    NASA Technical Reports Server (NTRS)

    Barrett, Joe, III; Bauman, William, III; Keen, Jeremy

    2007-01-01

    Meteorologists from the 45th Weather Squadron (45 WS) and Spaceflight Meteorology Group (SMG) have identified anvil forecasting as one of their most challenging tasks when predicting the probability of violations of the lightning Launch Commit Criteria and Space Shuttle Flight Rules. As a result, the Applied Meteorology Unit (AMU) created a graphical overlay tool for the Meteorological Interactive Data Display Systems (MIDDS) to indicate the threat of thunderstorm anvil clouds, using either observed or model forecast winds as input. In order for the Anvil Tool to remain available to the meteorologists, the AMU was tasked to transition the tool to the Advanced Weather interactive Processing System (AWIPS). This report describes the work done by the AMU to develop the Anvil Tool for AWIPS to create a graphical overlay depicting the threat from thunderstorm anvil clouds. The AWIPS Anvil Tool is based on the previously deployed AMU MIDDS Anvil Tool. SMG and 45 WS forecasters have used the MIDDS Anvil Tool during launch and landing operations. SMG's primary weather analysis and display system is now AWIPS and the 45 WS has plans to replace MIDDS with AWIPS. The Anvil Tool creates a graphic that users can overlay on satellite or radar imagery to depict the potential location of thunderstorm anvils one, two, and three hours into the future. The locations are based on an average of the upper-level observed or forecasted winds. The graphic includes 10 and 20 nm standoff circles centered at the location of interest, in addition to one-, two-, and three-hour arcs in the upwind direction. The arcs extend outward across a 30 degree sector width based on a previous AMU study which determined thunderstorm anvils move in a direction plus or minus 15 degrees of the upper-level (300- to 150-mb) wind direction. This report briefly describes the history of the MIDDS Anvil Tool and then explains how the initial development of the AWIPS Anvil Tool was carried out. After testing was

  13. Nowcasting Thunderstorm Anvil Clouds Over KSC/CCAFS

    NASA Technical Reports Server (NTRS)

    Short, David A.; Sardonia, James E.; Lambert, Winifred C.; Wheeler, Mark M.

    2004-01-01

    Electrified thunderstorm anvil clouds extend the threat of natural and triggered lightning to space launch and landing operations far beyond the immediate vicinity of thunderstorm cells. The deep convective updrafts of thunderstorms transport large amounts of water vapor, super-cooled water droplets and ice crystals into the upper troposphere, forming anvil clouds, which are then carried downstream by the prevailing winds in the anvil formation layer. Electrified anvil clouds have been observed over the space launch and landing facilities of Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS), emanating from thunderstorm activity more than 200 km distant. Space launch commit criteria and flight rules require launch and landing vehicles to avoid penetration of the non-transparent portion of anvil clouds. The life cycles of 167 anvil clouds over the Florida peninsula and its coastal waters were documented using GOES-8 visible imagery on 50 anvil case days during the months of May through July 2001. Anvil clouds were found to propagate at the speed and direction of upper-tropospheric winds in the layer from 300-to-l50 mb, approximately 9.4 km to 14 km, with an effective average transport lifetime of 2 hours and a standard deviation of approximately 30 minutes. The effective lifetime refers to the time required for the nontransparent leading edge of an anvil cloud to reach its maximum extent before beginning to dissipate. The propagation and lifetime information was incorporated into the design, construction and implementation of an objective short-range anvil forecast tool based on upper-air observations, for use on the Meteorological Interactive Data Display System within the Range Weather Operations facility of the 45th Weather Squadron at CCAFS and the Spaceflight Meteorology Group at Johnson Space Center.

  14. Multiple Diamond Anvil (MDA) apparatus using nano-polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Irifune, T.; Kunimoto, T.; Tange, Y.; Shinmei, T.; Isobe, F.; Kurio, A.; Funakoshi, K.

    2011-12-01

    Thanks to the great efforts by Dave Mao, Bill Bassett, Taro Takahashi, and their colleagues at the University of Rochester through 1960s-70s, diamond anvil cell (DAC) became a major tool to investigate the deep Earth after its invention by scientists at NBS in 1958. DAC can now cover almost the entire pressure and temperature regimes of the Earth's interior, which seems to have solved the longstanding debate on the crystal structure of iron under the P-T conditions of the Earth's inner core. In contrast, various types of static large-volume presses (LVP) have been invented, where tungsten carbide has conventionally been used as anvils. Kawai-type multianvil apparatus (MA), which utilize 6 first-stage harden steel and 8 tungsten carbide anvils, is the most successful LVP, and has been used for accurate measurements of phase transitions, physical properties, element partitioning, etc. at high pressure and temperature. However, pressures using tungsten carbide as the second-stage anvils have been limited to about 30 GPa due to significant plastic deformation of the anvils. Efforts have been made to expand this pressure limit by replacing tungsten carbide anvils with harder sintered diamond (SD) anvils over the last two decades, but the pressures available in KMA with SD anvils have still been limited to below 100 GPa. We succeeded to produce nano-polycrystalline diamond (NPD or HIME-Diamond) in 2003, which is known to have ultrahigh hardness, very high toughness and elastic stiffness, high transmittance of light, relatively low thermal conductivity. These properties are feasible for its use as anvils, and some preliminary experiments of application of NPD anvils to laser heated DAC have successfully made in the last few years. We are now able to synthesize NPD rods with about 1cm in both diameter and length using a newly constructed 6000-ton KMA at Geodynamics Research Center, Ehime University, and have just started to apply this new polycrystalline diamond as anvils

  15. Homoepitaxial Boron Doped Diamond Anvils as Heating Elements in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Montgomery, Jeffrey; Samudrala, Gopi; Smith, Spencer; Tsoi, Georgiy; Vohra, Yogesh; Weir, Samuel

    2013-03-01

    Recent advances in designer-diamond technology have allowed for the use of electrically and thermally conducting homoepitaxially-grown layers of boron-doped diamond (grown at 1200 °C with a 2% mixture of CH4 in H, resulting in extremely high doping levels ~ 1020/cm3) to be used as heating elements in a diamond anvil cell (DAC). These diamonds allow for precise control of the temperature inside of the diamond anvil itself, particularly when coupled with a cryostat. Furthermore, the unmatched thermally conducting nature of diamond ensures that no significant lateral gradient in temperature occurs across the culet area. Since a thermocouple can easily be attached anywhere on the diamond surface, we can also measure diamond temperatures directly. With two such heaters, one can raise sample temperatures uniformly, or with any desired gradient along the pressure axis while preserving optical access. In our continuing set of benchmark experiments, we use two newly created matching heater anvils with 500 μm culets to analyze the various fluorescence emission lines of ruby microspheres, which show more complicated behavior than traditional ruby chips. We also report on the temperature dependence of the high-pressure Raman modes of paracetamol (C8H9NO2) up to 20 GPa.

  16. Homoepitaxial Boron Doped Diamond Anvil as Heating Element in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Montgomery, Jeffrey; Samudrala, Gopi; Vohra, Yogesh

    2012-02-01

    Recent advances in designer-diamond technology have allowed for the use of electrically and thermally conducting homoepitaxially-grown layers of boron-doped diamond (grown at 1200 C with a 2% mixture of CH4 in H, resulting in extremely high doping levels ˜ 10^20/cm^3) to be used as heating elements in a diamond anvil cell (DAC). These diamonds allow for precise control of the temperature inside of the diamond anvil itself, particularly when coupled with a cryostat. Furthermore, the unmatched thermally conducting nature of diamond ensures that no significant spatial gradient in temperature occurs across the culet area. Since a thermocouple can easily be attached anywhere on the diamond surface, we can also measure diamond temperatures directly. With two such heaters, one can raise sample temperatures uniformly, or with any desired gradient along the pressure axis while preserving optical access. In our initial experiments with these diamond anvils we report on the measurement of the thermal conductivity of copper-beryllium using a single diamond heater and two thermocouples. We augment these measurements with measurements of sample pressure via ruby fluorescence and electrical resistance of the sample and diamond heater.

  17. Factors influencing the parameterization of tropical anvils within GCMs

    SciTech Connect

    Bradley, M.M.; Chin, H.N.S.

    1994-03-01

    The overall goal of this project is to improve the representation of anvil clouds and their effects in general circulation models (GCMs). We have concentrated on an important portion of the overall goal; the evolution of cumulus-generated anvil clouds and their effects on the large-scale environment. Because of the large range of spatial and temporal scales involved, we have been using a multi-scale approach. For the early-time generation and development of the citrus anvil we are using a cloud-scale model with a horizontal resolution of 1-2 kilometers, while for the transport of anvils by the large-scale flow we are using a mesoscale model with a horizontal resolution of 10-40 kilometers. The eventual goal is to use the information obtained from these simulations, together with available observations to develop an improved cloud parameterization for use in GCMS. The cloud-scale simulation of a midlatitude squall line case and the mesoscale study of a tropical anvil using an anvil generator were presented at the last ARM science team meeting. This paper concentrates on the cloud-scale study of a tropical squall line. Results are compared with its midlatitude counterparts to further our understanding of the formation mechanism of anvil clouds and the sensitivity of radiation to their optical properties.

  18. Generation of pressures over 40 GPa using Kawai-type multi-anvil press with tungsten carbide anvils.

    PubMed

    Ishii, T; Shi, L; Huang, R; Tsujino, N; Druzhbin, D; Myhill, R; Li, Y; Wang, L; Yamamoto, T; Miyajima, N; Kawazoe, T; Nishiyama, N; Higo, Y; Tange, Y; Katsura, T

    2016-02-01

    We have generated over 40 GPa pressures, namely, 43 and 44 GPa, at ambient temperature and 2000 K, respectively, using Kawai-type multi-anvil presses (KMAP) with tungsten carbide anvils for the first time. These high-pressure generations were achieved by combining the following pressure-generation techniques: (1) precisely aligned guide block systems, (2) high hardness of tungsten carbide, (3) tapering of second-stage anvil faces, (4) materials with high bulk modulus in a high-pressure cell, and (5) high heating efficiency.

  19. 4. FORGE, ANVIL, PEDESTAL GRINDER, AND BELT DRIVES. NOTE WATERWHEEL ...

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

    4. FORGE, ANVIL, PEDESTAL GRINDER, AND BELT DRIVES. NOTE WATERWHEEL NEEDLE VALVE CASTING HANGING ON THE WALL ABOVE THE FORGE. VIEW TO NORTH. - Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, San Bernardino County, CA

  20. The Case for Cooler Anvil Temperatures in the Tropics

    NASA Astrophysics Data System (ADS)

    Igel, M. R.; Stephens, G. L.; van den Heever, S. C.

    2011-12-01

    The Fixed Anvil Temperature (FAT) hypothesis states that the detrainment temperature of deep convective anvils in the tropics is controlled by processes which are themselves strongly controlled by upper tropospheric temperature only. Thus, FAT predicts that anvil temperatures should be constant regardless of surface temperature. FAT implicitly assumes upper tropospheric relative humidity (RH) is independent of surface temperature, and it is this assumption which leads this study to suggest that FAT could be only approximately valid. Mean anvil temperature is an important link between tropical convection and climate as it controls the local longwave cooling to space. As such, a detailed understanding of the processes that control anvils is integral to our understanding of tropical contributions to global climate. A mathematical model of cloud detrainment has been derived that shows sensitivity to relative humidity in addition to temperature. The sensitivity to RH is assessed mathematically and with simple numerical models. Results from a large-domain, high resolution Regional Atmospheric Modeling System (RAMS) cloud system resolving model run over fixed sea surface temperatures of 298K and 302K and equilibrated to radiative convective equilibrium are analyzed to compare to the results from the mathematical and numerical experiments. Results will consistently show that a new paradigm of Cooler Anvil Temperatures (CAT) may be warranted. If verified, CAT could be a significant, positive climate feedback.

  1. The balanced radiative effect of tropical anvil clouds

    NASA Astrophysics Data System (ADS)

    Hartmann, Dennis L.; Berry, Sara E.

    2017-05-01

    Coincident instantaneous broadband radiation budget measurements from Clouds and Earth's Radiant Energy System and cloud vertical structure information from CloudSat-Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations radar-lidar observations are combined to study the relationship of cloud vertical structure to top-of-atmosphere energy balance fluctuations. Varying optical and physical thickness of high ice clouds produces most of the covariation between albedo and outgoing longwave radiation in regions of tropical convection. Rainy cores of tropical convective clouds have a negative impact on the radiation balance, while nonprecipitating anvil clouds have a positive effect. The effect of anvil clouds on the radiative heating profile is to warm near cloud base and cool near cloud top, and to reduce the radiative cooling rate in the clear air below the cloud. The cooling rate in the clear air below the anvil is reduced to small values for moderately thick anvils, and the driving of instability in the anvil itself also saturates for relatively thin clouds. It is hypothesized that the dependence of radiative heating on cloud thickness may be important in driving the distribution of tropical cloud structures toward one that produces net neutrality of the cloud radiative effect at the top-of-the-atmosphere, as is found in regions of deep convection over ocean areas with high and relatively uniform surface temperatures. This idea is tested with a single-column model, which indicates that cloud-radiation interactions affect anvil cloud properties, encouraging further investigation of the hypothesis.

  2. Cdc2 and the Regulation of Mitosis: Six Interacting Mcs Genes

    PubMed Central

    Molz, L.; Booher, R.; Young, P.; Beach, D.

    1989-01-01

    A cdc2-3w weel-50 double mutant of fission yeast displays a temperature-sensitive lethal phenotype that is associated with gross abnormalities of chromosome segregation and has been termed mitotic catastrophe. In order to identify new genetic elements that might interact with the cdc2 protein kinase in the regulation of mitosis, we have isolated revertants of the lethal double mutant. The suppressor mutations define six mcs genes (mcs: mitotic catastrophe suppressor) that are not allelic to any of the following mitotic control genes: cdc2, wee1, cdc13, cdc25, suc1 or nim1. Each mcs mutation is recessive with respect to wild-type in its ability to suppress mitotic catastrophe. None confer a lethal phenotype as a single mutant but few of the mutants are expected to be nulls. A diverse range of genetic interactions between the mcs mutants and other mitotic regulators were uncovered, including the following examples. First, mcs2 cdc2w or mcs6 cdc2w double mutants display a cell cycle defect dependent on the specific wee allele of cdc2. Second, both mcs1 cdc25-22 or mcs4 cdc25-22 double mutants are nonconditionally lethal, even at a temperature normally permissive for cdc25-22. Finally, the characteristic suppression of the cdc25 phenotype by a loss-of-function wee1 mutation is reversed in a mcs3 mutant background. The mcs genes define new mitotic elements that might be activators or substrates of the cdc2 protein kinase. PMID:2474475

  3. Multi-scale evolution of a derecho-producing MCS

    NASA Astrophysics Data System (ADS)

    Bernardet, Ligia Ribeiro

    1997-12-01

    In this dissertation we address one type of severe weather: strong straight-line winds. In particular, we focus on derechos, a type of wind storm caused by a convective system and characterized by its long duration and by the large area it covers. One interesting characteristic of these storms is that they develop at night, on the cold side of a thermal boundary. This region is not characterized by large convective instability. In fact, surface parcels are generally stable with respect to vertical displacements. To gain understanding of the physical processes involved in these storms, we focused on the case of a MCS that developed in eastern Colorado on 12-13 May, 1985. The system formed in the afternoon, was active until early morning, and caused strong winds during the night. A multi-scale full physics simulation of this case was performed using a non-hydrostatic mesoscale model. Four telescopically nested grids covering from the synoptic scale down to cloud scale circulations were used. A Lagrangian model was used to follow trajectories of parcels that took part in the updraft and in the downdraft, and balance of forces were computed along the trajectories. Our results show that the synoptic and mesoscale environment of the storm largely influences convective organization and cloud-scale circulations. During the day, when the boundary layer is well mixed, the source of air for the clouds is located within the boundary layer. At night, when the boundary layer becomes stable, the source of air shifts to the top of the boundary layer. It is composed of warm, moist air that is brought by the nocturnal low-level jet. The downdraft structure also changes from day to night. During the day, parcels acquire negative buoyancy because of cooling due to evaporation and melting. As they sink, they remain colder than the environment, and end up at the surface constituting the cold pool. During the night, downdrafts are stronger, generating the strong surface winds. The most

  4. Aerosol effects on the anvil characteristics of mesoscale convective systems

    NASA Astrophysics Data System (ADS)

    Saleeby, S. M.; Heever, S. C.; Marinescu, P. J.; Kreidenweis, S. M.; DeMott, P. J.

    2016-09-01

    Simulations of two mesoscale convective systems (MCSs) that occurred during the Midlatitude Continental Convective Clouds Experiment were performed to examine the impact of aerosol number concentration on the vertical distributions of liquid and ice condensate and the macrophysical, microphysical, and radiative properties of the cirrus-anvil cloud shield. Analyses indicate that for an increase in aerosol concentration from a clean continental to a highly polluted state, there was an increase in the rime collection rate of cloud water, which led to less lofted cloud water. Aerosol-induced trends in the cloud mixing ratio profiles were, however, nonmonotonic in the mixed phase region, such that a moderate increase in aerosol concentration produced the greatest reduction in cloud water. Generally, less lofted cloud water led to less anvil ice mixing ratio but more numerous, small ice crystals within the anvil. In spite of reduced anvil ice mixing ratio, the anvil clouds exhibited greater areal coverage, increased albedo, reduced cloud top cooling, and reduced net radiative flux, which led to an aerosol-induced warming (reduced cooling) effect in these squall lines.

  5. Analysis of in situ measurements of cirrus anvil outflow dynamics

    NASA Astrophysics Data System (ADS)

    Lederman, J. I.; Whiteway, J. A.

    2012-12-01

    The airborne campaign, EMERALD 2 (Egrett Microphysics Experiment with Radiation, Lidar, and Dynamics,) was conducted out of Darwin, Australia in 2002. Objectives included characterization of the dynamics in the cirrus anvil outflow from tropical deep convection. Two aircraft, the Egrett and King Air, were flown in tandem in the upper troposphere (7 km - 15 km) to collect in situ measurements in the anvil outflow from a storm named "Hector" that occurs on a regular basis over the Tiwi Islands north of Darwin during November and December. Turbulence probes mounted on the wings of the Egrett aircraft were used to measure the wind fluctuations across the anvil and along its length with a spatial resolution of 2 meters. The in situ measurements from the Egrett were coincident with lidar measurements of the cloud structure from the King Air aircraft flying directly below. The presentation will show results of the analysis of the measurements with an emphasis on the turbulence, gravity waves, and coherent structures that are particular to the cirrus anvil outflow environment. Emphasis is placed on the dynamics associated with the generation of mammatus formations at the base of the anvil clouds.

  6. The Anvils as Pressure Calibrants in the Hydrothermal Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Davis, M. K.; Panero, W. R.; Stixrude, L. P.

    2003-12-01

    Throughout the crust and the upper part of the mantle, water is an important agent of heat and mass transport in processes ranging from metasomatism to magma generation in arc environments. One of the important properties of water in this regime: its ability to dissolve significant amounts of solids, presents a substantial challenge to the experimental study of water-rich systems. Many commonly used pressure standards, such as quartz and ruby, dissolve in water under the conditions accessible to the hydrothermal diamond anvil cell (up to 1200 K and 5 GPa). For this reason, it is important to develop alternative pressure calibrants. Two methods have been developed by other groups for pressure calibration in the HDAC in the presence of water. One method relies on the equation of state of the ambient fluid and the observation that the sample chamber remains approximately isochoric on heating. Disadvantages of this method include our imperfect knowledge of the equation of state of water over the relevant pressure-temperature interval, possible changes in fluid composition, and sample chamber assembly relaxation at temperatures above 800 K. The second method is based on the Raman signal from diamond chips loaded with the sample. Synthetic 13C diamond is used to avoid overlap with the much stronger signal from the anvils. Diamond is an ideal pressure sensor since it is chemically inert and unaffected by water. Therefore, we use the tips of the diamond anvils as "internal" sensors. The primary disadvantage of this method is that the stress distribution inside the anvils is non-hydrostatic and inhomogeneous, although the normal stress across the diamond-sample interface must be continuous. Using confocal micro-Raman spectroscopy we are able to characterize both the inhomogeneity and the non-hydrostaticity of the diamond stress field by combining axial and radial transects with peak shapes. We find that on room temperature loading there is substantial inhomogeneity in the

  7. Mars Climate Sounder (MCS) Observations of Martian Dust — A Decade-Long Record

    NASA Astrophysics Data System (ADS)

    Kass, D. M.; McCleese, D. J.; Kleinböhl, A.; Schofield, J. T.; Heavens, N. G.

    2017-06-01

    We describe the Mars Climate Sounder (MCS) observations of atmospheric dust. The instrument acquires infrared observations to produce a 5.75 Mars Year (>10 earth year) climatology global of dust, including its vertical distribution.

  8. Investigation on stress distribution of multilayered composite structure (MCS) using infrared thermographic technique

    NASA Astrophysics Data System (ADS)

    Liu, Junyan; Gong, Jinlong; Liu, Liqiang; Qin, Lei; Wang, Yang

    2013-11-01

    In this paper, the thermoelastic stress analysis (TSA) on a multilayered composite structure (MCS) was investigated by means of lock-in thermographic image technique (LITI). The application of thermoelastic stress analysis on MCS becomes particularly complicated due to consisting of different material components, which determines the different thermoelastic coupling response depended on material thermal-physical property. The thermoelastic coupling constants (TCC) of GFRP, medium-carbon steel and foam were obtained through thermomechanical calibration experiments, respectively. An artificial neural network was proposed to determine the component of MCS. Comparisons between finite element analysis (FEA) and LITI measurement are reported. It is found that the stress distribution of MCS can be evaluated with good accuracies using LITI measurement.

  9. Thermal Diffusivity and Conductivity Measurements in Diamond Anvil Cells

    SciTech Connect

    Antonangeli, D; Farber, D L

    2007-02-22

    We have undertaken a study of the feasibility of an innovative method for the determination of thermal properties of materials at extreme conditions. Our approach is essentiality an extension of the flash method to the geometry of the diamond-anvil cell and our ultimate goal is to greatly enlarge the pressure and temperature range over which thermal properties can be investigated. More specifically, we have performed test experiments to establish a technique for probing thermal diffusivity on samples of dimensions compatible with the physical constraints of the diamond anvil cell.

  10. Cloud resolving modelling of the life cycle of a MCS: Sensitivity to soil conditions over West Africa

    NASA Astrophysics Data System (ADS)

    Gantner, L.; Kalthoff, N.

    2009-09-01

    In the African Sahelian (12°N-18°N) and Sudanian climate zone (9°N-11°N) convective systems contribute about 80-90% and about 50%, respectively, to the annual rainfall. Thus, they play a key role in the water cycle of West Africa. Their rainfall, however, is highly variable in space as well as in time. The initiation and modification of rain-producing convective systems in West Africa are still not well understood. In addition to mid- and upper-tropospheric forcing, the influence of surface and convective boundary layer (CBL) processes on the initiation of convection is often emphasised. Major factors are the spatial distribution and temporal development of water vapour in the CBL. Besides advective processes, water vapour is made available in the atmosphere locally through evapotranspiration from soil and vegetation; the latter is an important component of the earth's surface energy balance. Soil moisture affects the energy balance via the albedo and emissivity of the surface, the conduction of heat in the soil and the stomata resistance of vegetation. Research findings show that the soil moisture exerts greater influence on the CBL than vegetation. Cloud resolving real-case simulations initialized with ECMWF analysis data were performed to investigate the sensitivity of a mesoscale convective system (MCS) to soil properties. Several scenarios with different content of soil moisture and distribution of soil conditions were investigated. Initiation of convection was observed in all experiments. The initiation area was characterised by very low convective inhibition (CIN) and high convective available potential energy. The simulations showed some evidence that convection was initiated in the vicinity of orography and along soil moisture inhomogeneities. In a moist case precipitating cells were weak and disappeared when entering a region with higher CIN. In the other experiments MCSs developed. In the control run a weakening of the system was observed when

  11. Anvil Forecast Tool in the Advanced Weather Interactive Processing System

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Hood, Doris

    2009-01-01

    Meteorologists from the 45th Weather Squadron (45 WS) and National Weather Service Spaceflight Meteorology Group (SMG) have identified anvil forecasting as one of their most challenging tasks when predicting the probability of violations of the Lightning Launch Commit Criteria and Space Shuttle Flight Rules. As a result, the Applied Meteorology Unit (AMU) was tasked to create a graphical overlay tool for the Meteorological Interactive Data Display System (MIDDS) that indicates the threat of thunderstorm anvil clouds, using either observed or model forecast winds as input. The tool creates a graphic depicting the potential location of thunderstorm anvils one, two, and three hours into the future. The locations are based on the average of the upper level observed or forecasted winds. The graphic includes 10 and 20 n mi standoff circles centered at the location of interest, as well as one-, two-, and three-hour arcs in the upwind direction. The arcs extend outward across a 30 sector width based on a previous AMU study that determined thunderstorm anvils move in a direction plus or minus 15 of the upper-level wind direction. The AMU was then tasked to transition the tool to the Advanced Weather Interactive Processing System (AWIPS). SMG later requested the tool be updated to provide more flexibility and quicker access to model data. This presentation describes the work performed by the AMU to transition the tool into AWIPS, as well as the subsequent improvements made to the tool.

  12. How to detect melting in laser heating diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Liuxiang, Yang

    2016-07-01

    Research on the melting phenomenon is the most challenging work in the high pressure/temperature field. Until now, large discrepancies still exist in the melting curve of iron, the most interesting and extensively studied element in geoscience research. Here we present a summary about techniques detecting melting in the laser heating diamond anvil cell.

  13. The simulation of a MCS event in the South America using a radiative transfer model

    NASA Astrophysics Data System (ADS)

    Silveira, B. B.; Aravéquia, J. A.

    2011-12-01

    The Mesoescale Convective Systems (MCS) have an important role in the total precipitation in some regions in the world. The Southeast of South America is one of these regions, because in this area the environment favors the development of MCS. The satellite image is an important data used in the identification and characterization of these systems. In these images the MCSs are characterize for have a low values of Brightness Temperature (BT). A channel utilized to identify these systems is 4 (infrared) of the sensor imager of GOES 10 satellite. With the objective of identify a MCS with an atmospheric model 12h forecast was realized a simulation of BT to channel 4 of GOES 10 using a radiative transfer model. The MCS event chosen was one that occur between 9 and 10 November 2008 and this system reached the North of Argentine and Paraguay. This MCS was identified using the outputs of FORTACC (Forecast and Tracking of Active Convective Cells). The BT simulation was realized using the radiative transfer model CRTM version 2.0.2 (Community Radiative Transfer Model) from JCSDA (Joint Center for Satellite Data Assimilation). To realize the simulation was used a 12 hours forecast from ETA model, this atmospheric model is an operational model from the CPTEC/INPE (Centro de Previsão de Tempo e Estudos Climáticos/ Instituto Nacional de Pesquisas Epaciais). The ETA model has 20x20 Km horizontal spatial resolution and 19 levels in the vertical. The simulation of BT values with CRTM indicates the region where the MCS occurred. However the BT values are overestimated by the CRTM, the simulated amounts are quantitatively higher than the observed by the channel 4 from GOES 10. The area with BT values related to the MCS is smaller than the observed in the satellite image, the system shape also wasn't simulated the satisfactory way.

  14. A proposal for a drug product Manufacturing Classification System (MCS) for oral solid dosage forms.

    PubMed

    Leane, Michael; Pitt, Kendal; Reynolds, Gavin

    2015-01-01

    This paper proposes the development of a drug product Manufacturing Classification System (MCS) based on processing route. It summarizes conclusions from a dedicated APS conference and subsequent discussion within APS focus groups and the MCS working party. The MCS is intended as a tool for pharmaceutical scientists to rank the feasibility of different processing routes for the manufacture of oral solid dosage forms, based on selected properties of the API and the needs of the formulation. It has many applications in pharmaceutical development, in particular, it will provide a common understanding of risk by defining what the "right particles" are, enable the selection of the best process, and aid subsequent transfer to manufacturing. The ultimate aim is one of prediction of product developability and processability based upon previous experience. This paper is intended to stimulate contribution from a broad range of stakeholders to develop the MCS concept further and apply it to practice. In particular, opinions are sought on what API properties are important when selecting or modifying materials to enable an efficient and robust pharmaceutical manufacturing process. Feedback can be given by replying to our dedicated e-mail address (mcs@apsgb.org); completing the survey on our LinkedIn site; or by attending one of our planned conference roundtable sessions.

  15. Sequence and batch language programs and alarm related C Programs for the 242-A MCS

    SciTech Connect

    Berger, J.F.

    1996-04-15

    A Distributive Process Control system was purchased by Project B-534, 242-A Evaporator/Crystallizer Upgrades. This control system, called the Monitor and Control system (MCS), was installed in the 242-A evaporator located in the 200 East Area. The purpose of the MCS is to monitor and control the Evaporator and monitor a number of alarms and other signals from various Tank Farm facilities. Applications software for the MCS was developed by the Waste Treatment Systems Engineering (WTSE) group of Westinghouse. The standard displays and alarm scheme provide for control and monitoring, but do not directly indicate the signal location or depict the overall process. To do this, WTSE developed a second alarm scheme.

  16. Pressure, stress, and strain distribution in the double-stage diamond anvil cell

    SciTech Connect

    Lobanov, Sergey S.; Prakapenka, Vitali B.; Prescher, Clemens; Konôpková, Zuzana; Liermann, Hanns-Peter; Crispin, Katherine L.; Zhang, Chi; Goncharov, Alexander F.

    2015-07-21

    Double stage diamond anvil cells (DACs) of two designs have been assembled and tested. We used a standard symmetric DAC with flat or beveled culets as a primary stage and CVD microanvils machined by a focused ion beam as a second. We evaluated pressure, stress, and strain distributions in gold and a mixture of gold and iron as well as in secondary anvils using synchrotron x-ray diffraction with a micro-focused beam. A maximum pressure of 240 GPa was reached independent of the first stage anvil culet size. We found that the stress field generated by the second stage anvils is typical of conventional DAC experiments. The maximum pressures reached are limited by strains developing in the secondary anvil and by cupping of the first stage diamond anvil in the presented experimental designs. Also, our experiments show that pressures of several megabars may be reached without sacrificing the first stage diamond anvils.

  17. A hydrothermal anvil made of graphene nanobubbles on diamond.

    PubMed

    Lim, Candy Haley Yi Xuan; Sorkin, Anastassia; Bao, Qiaoliang; Li, Ang; Zhang, Kai; Nesladek, Milos; Loh, Kian Ping

    2013-01-01

    The hardness and virtual incompressibility of diamond allow it to be used in high-pressure anvil cell. Here we report a new way to generate static pressure by encapsulating single-crystal diamond with graphene membrane, the latter is well known for its superior nano-indentation strength and in-plane rigidity. Heating the diamond-graphene interface to the reconstruction temperature of diamond (~1,275 K) produces a high density of graphene nanobubbles that can trap water. At high temperature, chemical bonding between graphene and diamond is robust enough to allow the hybrid interface to act as a hydrothermal anvil cell due to the impermeability of graphene. Superheated water trapped within the pressurized graphene nanobubbles is observed to etch the diamond surface to produce a high density of square-shaped voids. The molecular structure of superheated water trapped in the bubble is probed using vibrational spectroscopy and dynamic changes in the hydrogen-bonding environment are observed.

  18. CRYSTAL: The Cirrus Regional Study of Tropical Anvils and Layers

    NASA Technical Reports Server (NTRS)

    Delnore, Victor E.; Cox, Stephen K.; Curran, Robert J.

    1999-01-01

    CRYSTAL the Cirrus Regional Study of Tropical Anvils and Layers is part of the ongoing series of field experiments to study clouds and their impact on world weather and climate, and will attempt to improve the application of cloud effects in global climate models. CRYSTAL is being planned as two parts: a limited CRYSTAL field campaign in 2001 to examine towering clouds and anvil genesis over the Everglades of Florida, and the main CRYSTAL field campaign in the summer of 2003 in the Tropical Western Pacific. The latter is timed to take advantage of several cloud measurement satellites that will be operational at that time. This paper discusses some of the issues to be addressed in CRYSTAL, gives a brief description of the research plan, and describes its relationship to other important field experiments.

  19. Satellite-observed characteristics of midwest severe thunderstorm anvils

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Blackmer, Roy H., Jr.

    1988-01-01

    The cloud top and anvil structure of severe thunderstorms observed by the GOES satellite are analyzed for five SESAME cases in 1979 and four non-SESAME cases in 1980-1982. The data is compared with previous models and hypotheses, paying particular attention to the V feature and thermal couplets in the IR observations. The characteristics of the cases are examined and related to the upper-level temperature and wind conditions. It is found that the warm points downwind of the cloud top are due to subsidence. The anaylsis suggests the presence of subsidence due to mountainlike waves. A model in which the close-in warm point is produced by both internal cloud air motions and stratospheric flow around and over the cloud top. It is suggested that the distant warm point is due to either a wave perturbation from air flowing over the cloud top, or air flowing horizonatlly around the elevated portion of the cloud top and anvil.

  20. Rat Mcs5a is a compound quantitative trait locus with orthologous human loci that associate with breast cancer risk

    PubMed Central

    Samuelson, David J.; Hesselson, Stephanie E.; Aperavich, Beth A.; Zan, Yunhong; Haag, Jill D.; Trentham-Dietz, Amy; Hampton, John M.; Mau, Bob; Chen, Kai-Shun; Baynes, Caroline; Khaw, Kay-Tee; Luben, Robert; Perkins, Barbara; Shah, Mitul; Pharoah, Paul D.; Dunning, Alison M.; Easton, Doug F.; Ponder, Bruce A.; Gould, Michael N.

    2007-01-01

    Breast cancer risk is a polygenic trait. To identify breast cancer modifier alleles that have a high population frequency and low penetrance we used a comparative genomics approach. Quantitative trait loci (QTL) were initially identified by linkage analysis in a rat mammary carcinogenesis model followed by verification in congenic rats carrying the specific QTL allele under study. The Mcs5a locus was identified by fine-mapping Mcs5 in a congenic model. Here we characterize the Mcs5a locus, which when homozygous for the Wky allele, reduces mammary cancer risk by 50%. The Mcs5a locus is a compound QTL with at least two noncoding interacting elements: Mcs5a1 and Mcs5a2. The resistance phenotype is only observed in rats carrying at least one copy of the Wky allele of each element on the same chromosome. Mcs5a1 is located within the ubiquitin ligase Fbxo10, whereas Mcs5a2 includes the 5′ portion of Frmpd1. Resistant congenic rats show a down-regulation of Fbxo10 in the thymus and an up-regulation of Frmpd1 in the spleen. The association of the Mcs5a1 and Mcs5a2 human orthologs with breast cancer was tested in two population-based breast cancer case-control studies (≈12,000 women). The minor alleles of rs6476643 (MCS5A1) and rs2182317 (MCS5A2) were independently associated with breast cancer risk. The minor allele of rs6476643 increases risk, whereas the rs2182317 minor allele decreases risk. Both alleles have a high population frequency and a low penetrance toward breast cancer risk. PMID:17404222

  1. Thickness measurement of sample in diamond anvil cell.

    PubMed

    Li, Ming; Gao, Chunxiao; Peng, Gang; He, Chunyuan; Hao, Aimin; Huang, Xiaowei; Zhang, Dongmei; Yu, Cuiling; Ma, Yanzhang; Zou, Guangtian

    2007-07-01

    We report on an original method that measures sample thickness in a diamond anvil cell under high pressures. The method is based on two hypotheses: completely plastic deformation on the gasket and completely elastic deformation of the diamonds. This method can further eliminate the effect of diamond deformation on the thickness measurement of a sample, which permits us to measure the thickness of alumina up to 41.4 GPa.

  2. Acceptance test report for W-030 monitor and control system (MCS) software

    SciTech Connect

    Finch, B.G.

    1996-05-06

    This report documents the test performed under `Acceptance Test Procedure WHC-SD-W030-ATP-011, Rev. 0`, for `Project W-030 Tank Farm Ventilation Upgrade`. This report covers testing of the Software Control Logic for the MICON Monitoring and Control System (MCS).

  3. Clinical characteristics of chemical sensitivity: an illustrative case history of asthma and MCS.

    PubMed

    Ross, G H

    1997-03-01

    A case history of the induction of asthma and chemical sensitivity in a 42-year-old registered nurse illustrates several of the characteristic features of multiple chemical sensitivity (MCS). This patient's problems started shortly after moving into a new home under construction, with associated chemical exposures. Other MCS patients report the onset of the condition with other chemical exposures such as those encountered at their places of work or use of pesticides at their residences. Patients often describe a spreading phenomenon of increasing intolerance to commonly encountered chemicals at concentrations well tolerated by other people. Symptoms usually wax and wane with exposures, and are more likely to occur in patients or families with preexisting histories of migraine or with classical allergies. Idiosyncratic medication reactions (especially to preservative chemicals) are common in MCS patients, as are dysautonomia symptoms (such as vascular instability) and poor temperature regulation. Myalgia and joint pains and food intolerance are common features as well. Contamination with xenobiotic chemicals is frequently found in these patients when they are tested. Reactive airways dysfunction syndrome is a recently identified condition that exhibits features of both asthma and chemical sensitivity. MCS patients frequently have patterns of neurotoxic brain metabolism that can be confirmed on single photo emission computed tomography imaging.

  4. Clinical characteristics of chemical sensitivity: an illustrative case history of asthma and MCS.

    PubMed Central

    Ross, G H

    1997-01-01

    A case history of the induction of asthma and chemical sensitivity in a 42-year-old registered nurse illustrates several of the characteristic features of multiple chemical sensitivity (MCS). This patient's problems started shortly after moving into a new home under construction, with associated chemical exposures. Other MCS patients report the onset of the condition with other chemical exposures such as those encountered at their places of work or use of pesticides at their residences. Patients often describe a spreading phenomenon of increasing intolerance to commonly encountered chemicals at concentrations well tolerated by other people. Symptoms usually wax and wane with exposures, and are more likely to occur in patients or families with preexisting histories of migraine or with classical allergies. Idiosyncratic medication reactions (especially to preservative chemicals) are common in MCS patients, as are dysautonomia symptoms (such as vascular instability) and poor temperature regulation. Myalgia and joint pains and food intolerance are common features as well. Contamination with xenobiotic chemicals is frequently found in these patients when they are tested. Reactive airways dysfunction syndrome is a recently identified condition that exhibits features of both asthma and chemical sensitivity. MCS patients frequently have patterns of neurotoxic brain metabolism that can be confirmed on single photo emission computed tomography imaging. PMID:9167976

  5. Comparative study of plateletpheresis using Baxter CS 3000 plus and Haemonetics MCS 3P.

    PubMed

    Patel, Ashwin P; Kaur, Amarjit; Patel, Vinod; Patel, Narendra; Shah, Dilip; Kanvinde, Sunil; Prajapati, Sanjay; Patel, Hiral; Rathod, Dinesh; Adesara, Rashmin; Rani, Shubha

    2004-01-01

    Platelet concentrates made from cell separators are used more frequently due to less donor exposure and leucodepletion. This retrospective study was done to compare plateletpheresis done on two cell separators: Baxter CS 3000 plus and Haemonetics MCS 3p. Plateletpheresis procedures, done from January 1997 to April 2002, were included in the study. One hundred and seven procedures were done on Haemonetics MCS 3p using SDP protocol, 49 procedures were done on Haemonetics MCS 3p using PLP protocol, and 107 were done on Baxter CS 3000 plus. Pre-procedure donor's platelet count and haemoglobin were comparable in all the groups. Platelet yield was comparable in PLP (6.44 x 10(11) platelets) and SDP (5.27 x 10(11)) protocols, but significantly less in Baxter (4.05 x 10(11) platelets, P < 0.001 for PLP and P < 0.05 for SDP). Efficiency of platelet removal was statistically significantly different in all the groups (P < 0.0001), however it was more in PLP (PLP-55.02%, SDP-47.38%, Baxter 38.98%). A significant number of products (19.51%) of Baxter failed to comply platelet count of product < or = 2,435 x 10(9)/l compared to 5.13% in PLP and 1.23% in SDP group; 36.96% of units from PLP and 28% from SDP qualified for split products compared to 1.18% of Baxter. PLP protocol of Haemonetics MCS 3p gives better platelet yield compared to Baxter CS 3000 plus and SDP protocol of Haemonetics MCS 3p.

  6. Multiple chemical sensitivity (MCS)--differential diagnosis in clinical neurotoxicology: a German perspective.

    PubMed

    Altenkirch, H

    2000-08-01

    The multiple chemical sensitivity syndrome (MCS) is a new cluster of environmental symptoms which have been described and commented on for more than 15 years now in the USA. In the meantime it has also been observed in European countries. The main features of this syndrome are: multiple symptoms in multiple organ systems, precipitated by a variety of chemical substances with relapses and exacerbation under certain conditions when exposed to very low levels which do not affect the population at large. There are no lab markers or specific investigative findings. In our view, MCS is not a separate clinical syndrome but a collective term. A very small part of the patients in question may actually exhibit a somatic or psychosomatic response to low levels of a variety of chemicals in the environment. For another part, even if the MCS symptoms are induced by chemical substances in the environment, the basic hypersensitivity is a psychological stress reaction. In the third and largest group, the patients have been misdiagnosed, i.e. a somatic or psychiatric disease has been overlooked. There is a fourth group of patients in whom there is no evidence of any exposure at all but instead a belief system installed by certain physicians, the media and other groups in society. This paper tries to describe the neurological and neurotoxic aspects of MCS problems and to illustrate it with examples of an alleged outbreak of chronic neurotoxic disease caused by pyrethroids in Germany. Research strategy should establish clearly determined diagnostic criteria, agreement on the use of specific questionnaires as well as clinical and technical diagnostic procedures, prospective clinical studies of MCS patients and comparative groups as well as experimental approaches.

  7. HYBRID BRIDGMAN ANVIL DESIGN: AN OPTICAL WINDOW FOR IN-SITU SPECTROSCOPY IN LARGE VOLUME PRESSES

    SciTech Connect

    Lipp, M J; Evans, W J; Yoo, C S

    2005-07-29

    The absence of in-situ optical probes for large volume presses often limits their application to high-pressure materials research. In this paper, we present a unique anvil/optical window-design for use in large volume presses, which consists of an inverted diamond anvil seated in a Bridgman type anvil. A small cylindrical aperture through the Bridgman anvil ending at the back of diamond anvil allows optical access to the sample chamber and permits direct optical spectroscopy measurements, such as ruby fluorescence (in-situ pressure) or Raman spectroscopy. This performance of this anvil-design has been demonstrated by loading KBr to a pressure of 14.5 GPa.

  8. Comparison of plateletpheresis on the Fresenius AS.TEC 204 and Haemonetics MCS 3p.

    PubMed

    Ranganathan, Sudha

    2007-02-01

    This is an attempt at comparing two cell separators for plateletpheresis, namely the Fresenius AS.TEC 204 and Haemonetics MCS 3p, at a tertiary care center in India. Donors who weighed between 55-75 kg, who had a hematocrit of 41-43%, and platelet counts of 250x10(3)-400x10(3)/microl were selected for the study. The comparability of the donors who donated on the two cell separators were analysed by t-test independent samples and no significant differences were found (P>0.05). The features compared were time taken for the procedure, volume processed on the separators, adverse reactions of the donors, quality control of the product, separation efficiency of the separators, platelet loss in the donors after the procedure, and the predictor versus the actual yield of platelets given by the cell separator. The volume processed to get a target yield of >3x10(11) was equal to 2.8-3.2 l and equal in both the cell separators. Symptoms of citrate toxicity were seen in 4 and 2.5% of donors who donated on the MCS 3p and the AS.TEC 204, respectively, and 3 and 1% of donors, respectively, had vasovagal reactions. All the platelet products collected had a platelet count of >3x10(11); 90% of the platelet products collected on the AS.TEC 204 attained the predicted yield that was set on the cell separator where as 75% of the platelet products collected on the MCS 3p attained the target yield. Quality control of the platelets collected on both the cell separators complied with the standards except that 3% of the platelets collected on the MCS 3p had a visible red cell contamination. The separation efficiency of the MCS 3p was higher, 50-52% as compared to the 40-45% on the AS.TEC 204. A provision of double venous access, less adverse reactions, negligible RBC contamination with a better predictor yield of platelets makes the AS.TEC 204 a safer and more reliable alternative than the widely used Haemonetics MCS 3p.

  9. Stone Anvil Damage by Wild Bearded Capuchins (Sapajus libidinosus) during Pounding Tool Use: A Field Experiment

    PubMed Central

    Haslam, Michael; Cardoso, Raphael Moura; Visalberghi, Elisabetta; Fragaszy, Dorothy

    2014-01-01

    We recorded the damage that wild bearded capuchin monkeys (Sapajus libidinosus) caused to a sandstone anvil during pounding stone tool use, in an experimental setting. The anvil was undamaged when set up at the Fazenda Boa Vista (FBV) field laboratory in Piauí, Brazil, and subsequently the monkeys indirectly created a series of pits and destroyed the anvil surface by cracking palm nuts on it. We measured the size and rate of pit formation, and recorded when adult and immature monkeys removed loose material from the anvil surface. We found that new pits were formed with approximately every 10 nuts cracked, (corresponding to an average of 38 strikes with a stone tool), and that adult males were the primary initiators of new pit positions on the anvil. Whole nuts were preferentially placed within pits for cracking, and partially-broken nuts outside the established pits. Visible anvil damage was rapid, occurring within a day of the anvil's introduction to the field laboratory. Destruction of the anvil through use has continued for three years since the experiment, resulting in both a pitted surface and a surrounding archaeological debris field that replicate features seen at natural FBV anvils. PMID:25372879

  10. Comparison of Simulated and Observed Continental Tropical Anvil Clouds and Their Radiative Heating Profiles

    SciTech Connect

    Powell, Scott W.; Houze, R.; Kumar, Anil; McFarlane, Sally A.

    2012-09-06

    Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model using six different microphysical schemes. The radar data provide the statistical distribution of the radar reflectivity values as a function of height and anvil thickness. These statistics are compared to the statistics of the modeled anvil cloud reflectivity at all altitudes. Requiring the model to be statistically accurate at all altitudes is a stringent test of the model performance. The typical vertical profile of radiative heating in the anvil clouds is computed from the radar observations. Variability of anvil structures from the different microphysical schemes provides an estimate of the inherent uncertainty in anvil radiative heating profiles. All schemes underestimate the optical thickness of thin anvils and cirrus, resulting in a bias of excessive net anvil heating in all of the simulations.

  11. Raman Shift of Stressed Diamond Anvils: Pressure Calibration and Culet Geometry Dependence

    SciTech Connect

    Baer, B J; Chang, M E; Evans, W J

    2008-04-03

    The pressure dependence of the Raman shift of diamond for highly stressed anvils at the diamond-anvil sample interface has been measured for different culet shapes up to 180 GPa at ambient temperature. By using hydrogen samples, which constitute both a quasi-hydrostatic medium and a sensitive pressure sensor, some of the effects of culet and tip size have been determined. We propose that the divergent results in the literature can be partly ascribed to different anvil geometries. Experiments show increasing second order dependence of the diamond Raman shift with pressure for decreasing tip size. This is an important consideration when using the diamond anvils as a pressure sensor.

  12. Cloud resolving modelling of the life cycle of a MCS: Sensitivity to soil conditions over West Africa

    NASA Astrophysics Data System (ADS)

    Gantner, L.; Kalthoff, N.

    2009-04-01

    In the African Sahelian (12°N-18°N) and Sudanian climate zone (9°N-11°N) convective systems contribute about 80-90% and about 50%, respectively, to the annual rainfall. Thus, they play a key role in the water cycle of West Africa. Their rainfall, however, is highly variable in space as well as in time. The initiation and modification of rain-producing convective systems in West Africa are still not well understood. The development of moist convection requires any kind of instability like potential and/or conditional instability and a trigger mechanism like vertical motion. The latter process is needed to release the available energy for convection. The type of convection, i.e. shallow or deep convection, then depends on atmospheric stratification above the condensation level, the presence of lids which may inhibit convection, and the height of the equilibrium level. In addition to mid- and upper-tropospheric forcing, the influence of surface and convective boundary layer (CBL) processes on the initiation of convection is often emphasised. Major factors are the spatial distribution and temporal development of water vapour in the CBL. Besides advective processes, water vapour is made available in the atmosphere locally through evapotranspiration from soil and vegetation; the latter is an important component of the earth's surface energy balance. Soil moisture affects the energy balance via the albedo and emissivity of the surface, the conduction of heat in the soil and the stomata resistance of vegetation. Research findings show that the soil moisture exerts greater influence on the CBL than vegetation Cloud resolving real-case simulations initialized with ECMWF analysis data were performed to investigate the sensitivity of a mesoscale convective system (MCS) to soil properties. Several scenarios with different content of soil moisture and distribution of soil conditions were investigated. Initiation of convection was observed in all experiments. The initiation

  13. DisoMCS: Accurately Predicting Protein Intrinsically Disordered Regions Using a Multi-Class Conservative Score Approach

    PubMed Central

    Wang, Zhiheng; Yang, Qianqian; Li, Tonghua; Cong, Peisheng

    2015-01-01

    The precise prediction of protein intrinsically disordered regions, which play a crucial role in biological procedures, is a necessary prerequisite to further the understanding of the principles and mechanisms of protein function. Here, we propose a novel predictor, DisoMCS, which is a more accurate predictor of protein intrinsically disordered regions. The DisoMCS bases on an original multi-class conservative score (MCS) obtained by sequence-order/disorder alignment. Initially, near-disorder regions are defined on fragments located at both the terminus of an ordered region connecting a disordered region. Then the multi-class conservative score is generated by sequence alignment against a known structure database and represented as order, near-disorder and disorder conservative scores. The MCS of each amino acid has three elements: order, near-disorder and disorder profiles. Finally, the MCS is exploited as features to identify disordered regions in sequences. DisoMCS utilizes a non-redundant data set as the training set, MCS and predicted secondary structure as features, and a conditional random field as the classification algorithm. In predicted near-disorder regions a residue is determined as an order or a disorder according to the optimized decision threshold. DisoMCS was evaluated by cross-validation, large-scale prediction, independent tests and CASP (Critical Assessment of Techniques for Protein Structure Prediction) tests. All results confirmed that DisoMCS was very competitive in terms of accuracy of prediction when compared with well-established publicly available disordered region predictors. It also indicated our approach was more accurate when a query has higher homologous with the knowledge database. Availability The DisoMCS is available at http://cal.tongji.edu.cn/disorder/. PMID:26090958

  14. Refinement of pressure calibration for multi-anvil press experiments

    NASA Astrophysics Data System (ADS)

    Ono, S.

    2016-12-01

    Accurate characterization of the pressure and temperature environment in high-pressure apparatuses is of essential importance when we apply laboratory data to the study of the Earth's interior. Recently, the synchrotron X-ray source can be used for the high-pressure experiments, and the in situ pressure calibration has been a common technique. However, this technique cannot be used in the laboratory-based experiments. Even now, the conventional pressure calibration is of great interest to understand the Earth's interior. Several high-pressure phase transitions used as the pressure calibrants in the laboratory-based multi-anvil experiments have been investigated. Precise determinations of phase boundaries of CaGeO3 [1], Fe2SiO4 [2], SiO2, and Zr [3] were performed by the multi-anvil press or the diamond anvil cell apparatuses combined with the synchrotron X-ray diffraction technique. The transition pressures in CaGeO3 (garnet-perovskite), Fe2SiO4 (alfa-gamma), and SiO2 (coesite-stishovite) were in general agreement with those reported by previous studies. However, significant discrepancies for the slopes, dP/dT, of these transitions between our and previous studies were confirmed. In the case of Zr study [3], our experimental results elucidate the inconsistency in the transition pressure between omega and beta phase in Zr observed in previous studies. [1] Ono et al. (2011) Phys. Chem. Minerals, 38, 735-740.[2] Ono et al. (2013) Phys. Chem. Minerals, 40, 811-816.[3] Ono & Kikegawa (2015) J. Solid State Chem., 225, 110-113.

  15. Very high pressure Moessbauer spectroscopy using diamond anvil cells

    SciTech Connect

    Pasternak, M.P.; Taylor, R.D.

    1988-01-01

    The technique of generating very high pressure by means of Diamond Anvil Cells (DAC) for Mossbauer Effect applications is outlined. A comprehensive description is presented of the principles of DAC, modification for the use in M/umlt o/ssbauer Spectroscopy (MS), the Merrill--Bassett and Bassett cells, of pressure measurements, of gasketing and collimation, and of hydrostatic media. Examples of /sup 151/Eu, /sup 119/Sn and /sup 129/I are given showing the feasibility of DAC applications in MS. Other isotopes with potential use for high pressure MS using DAC are suggested. 27 refs., 9 figs.

  16. Elimination of pressure-induced fluorescence in diamond anvils

    NASA Technical Reports Server (NTRS)

    Eggert, Jon H.; Goettel, Kenneth A.; Silvera, Isaac F.

    1988-01-01

    At pressures above one megabar (100 GPa) in high-pressure diamond anvil cell experiments, the ruby fluorescence signal needed for pressure calibration is increasingly difficult to measure. A primary cause of this difficulty is the presence of an intense pressure-induced diamond fluorescence. A tentative identification of this pressure-induced fluorescence is given, a technique for the elimination of this fluorescence is reported. It is demonstrated that weak ruby signals, completely hidden by diamond fluorescence, are now easily measured with this technique.

  17. Pressure measurement using the R fluorescence peaks and 417 cm-1 Raman peak of an anvil in a sapphire-anvil cell

    NASA Astrophysics Data System (ADS)

    Gao, Rong; Li, Heping

    2012-06-01

    In this study, synthetic sapphire crystals were used as anvils, coupled with a metal gasket, in a Merrill-Bassett-type pressure cell (sapphire-anvil cell (SAC)). Quartz and ruby chips were compressed in the cell and used as pressure calibrators for the SAC. In the sample-anvil interface, the relationship of the frequency shifts of the R1, R2 and 417 cm-1 peaks with pressure was studied. They were constructed as new pressure calibrators. To test the applicability of the newly calibrated SAC, the Raman spectra of dolomite and calcite were measured in situ at room temperature.

  18. Constraining mass-diameter relations from hydrometeor images and cloud radar reflectivities in tropical continental and oceanic convective anvils

    NASA Astrophysics Data System (ADS)

    Fontaine, E.; Schwarzenboeck, A.; Delanoë, J.; Wobrock, W.; Leroy, D.; Dupuy, R.; Protat, A.

    2014-01-01

    In this study the density of hydrometeors in tropical clouds is derived from a combined analysis of particle images from 2-D-array probes and associated reflectivities measured with a Doppler cloud radar on the same research aircraft. The mass-diameter m(D) relationship is expressed as a power law with two unknown coefficients (pre-factor, exponent) that need to be constrained from complementary information on hydrometeors, where absolute ice density measurement methods do not apply. Here, at first an extended theoretical study of numerous hydrometeor shapes simulated in 3-D and arbitrarily projected on a 2-D plane allowed to constrain the temporal evolution of the exponent of the mass-diameter relationship with that of the exponent of the surface-diameter relationship that is measured by the 2-D-array probes. The pre-factor is then constrained from theoretical simulations of the radar reflectivities matching the measured reflectivities along the aircraft trajectory. The study has been performed as part of the Megha-Tropiques satellite project, where two types of mesoscale convective systems (MCS) have been investigated: (i) above the African Continent and (ii) above the Indian Ocean. In general, both mass-diameter coefficients (pre-factor and exponent) decrease with decreasing temperature, the decrease is more pronounced for oceanic MCS. The condensed water contents (CWC) calculated from particle size distributions (PSD) and m(D) also decrease with altitude while the concentrations of the hydrometeors increase with altitude. The calculated values of CWC are largest for continental MCS.

  19. Effective Ice Particle Densities for Cold Anvil Cirrus

    NASA Technical Reports Server (NTRS)

    Heymsfield, Andrew J.; Schmitt, Carl G.; Bansemer, Aaron; Baumgardner, Darrel; Weinstock, Elliot M.; Smith, Jessica

    2002-01-01

    This study derives effective ice particle densities from data collected from the NASA WB-57F aircraft near the tops of anvils during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) in southern Florida in July 2002. The effective density, defined as the ice particle mass divided by the volume of an equivalent diameter liquid sphere, is obtained for particle populations and single sizes containing mixed particle habits using measurements of condensed water content and particle size distributions. The mean effective densities for populations decrease with increasing slopes of the gamma size distributions fitted to the size distributions. The population-mean densities range from near 0.91 g/cu m to 0.15 g/cu m. Effective densities for single sizes obey a power-law with an exponent of about -0.55, somewhat less steep than found from earlier studies. Our interpretations apply to samples where particle sizes are generally below 200-300 microns in maximum dimension because of probe limitations.

  20. High temperature diamond film deposition on a natural diamond anvil

    SciTech Connect

    McCauley, T.S.; Vohra, Y.K.

    1995-12-31

    We report on the growth and characterization of a 100 {mu}m thick by 350 {mu}m diameter diamond layer on the culet of a type Ia brilliant cut natural diamond anvil by microwave plasma-assisted CVD (MPCVD). While our previous work [1] on diamond anvils resulted in homoepitaxial film growth at a rate of approximately 20 {mu}m/hr, the present 100 {mu}m thick diamond layer grew in less than 2 hours. This unprecedented growth rate of {approximately} 50 {mu}m/hr is believed to be the result of the extremely high substrate temperature (1800{degrees}-2100{degrees}C) during deposition. The translucent diamond layer was characterized by micro-Raman, low temperature photoluminescence (PL) and PL excitation spectroscopy, as well as atomic force microscopy (AFM). Raman analysis shows the deposit to be of high quality. The PL spectra show numerous features, including prominent emission bands at 575 nm (2.16 eV), 636 nm (1.95 eV), 735 nm (1.68 eV) and 777 run, (1.60 eV).

  1. Organelle Communication at Membrane Contact Sites (MCS): From Curiosity to Center Stage in Cell Biology and Biomedical Research.

    PubMed

    Simmen, Thomas; Tagaya, Mitsuo

    2017-01-01

    Cell biology has long recognized that organelles can communicate with each other. Initially, such communication was thought to occur primarily via vesicular trafficking between biochemically distinct organelles. However, studies starting in the 1970s on lipid metabolism have unearthed another way how organelles can communicate and have spawned the field of membrane contact sites (MCS). While, initially, MCS had been recognized as fluid entities that mediate lipid and ion transport in an ad hoc manner, more recently MCS have been found to depend on protein-protein interactions that control themselves a variety of MCS functions. As a result, the cell biological definition of an intracellular organelle as an isolated membrane compartment is now being revised. Accordingly, the organelle definition now describes organelles as dynamic membrane compartments that function in a milieu of coordinated contacts with other organelles. Through these mercurial functions, MCS dictate the function of organelles to a large extent but also play important roles in a number of diseases, including type 2 diabetes, neurodegenerative diseases, infections, and cancer. This book assembles reviews that describe our quickly evolving knowledge about organellar communication on MCS and the significance of MCS for disease.

  2. High pressure studies using two-stage diamond micro-anvils grown by chemical vapor deposition

    SciTech Connect

    Vohra, Yogesh K.; Samudrala, Gopi K.; Moore, Samuel L.; Montgomery, Jeffrey M.; Tsoi, Georgiy M.; Velisavljevic, Nenad

    2015-06-10

    Ultra-high static pressures have been achieved in the laboratory using a two-stage micro-ball nanodiamond anvils as well as a two-stage micro-paired diamond anvils machined using a focused ion-beam system. The two-stage diamond anvils’ designs implemented thus far suffer from a limitation of one diamond anvil sliding past another anvil at extreme conditions. We describe a new method of fabricating two-stage diamond micro-anvils using a tungsten mask on a standard diamond anvil followed by microwave plasma chemical vapor deposition (CVD) homoepitaxial diamond growth. A prototype two stage diamond anvil with 300 μm culet and with a CVD diamond second stage of 50 μm in diameter was fabricated. We have carried out preliminary high pressure X-ray diffraction studies on a sample of rare-earth metal lutetium sample with a copper pressure standard to 86 GPa. Furthermore, the micro-anvil grown by CVD remained intact during indentation of gasket as well as on decompression from the highest pressure of 86 GPa.

  3. Resistance heating of the gasket in a gem-anvil high pressure cell

    NASA Astrophysics Data System (ADS)

    Balzaretti, N. M.; Gonzalez, E. J.; Piermarini, G. J.; Russell, T. P.

    1999-11-01

    Resistance heating of the gasket strip in a gem-anvil high pressure cell was successful in obtaining sample temperatures up to 1100 °C, under pressures up to 4.0 GPa. The heating capabilities, as well as the mechanical and chemical stability, of several different gasket strips (two Ni-based alloys, Ta, Pt/Rh, and a Re/Mo alloy) with different design shapes, and two different single-crystal anvil materials (diamond and cubic zirconia) were investigated. Two gasket-strip designs were found to provide optimum uniform heating conditions while decreasing the required current needed to achieve 1100 °C. Two anvil systems were investigated to reduce the temperature increase of the pressure cell body. Cubic zirconia anvils reduced the cell-body temperature to 100 °C at sample temperatures up to 1100 °C. However, zirconia anvils often failed during heating and almost always failed during cooling. Diamond anvils with cubic zirconia mounting plates also permitted temperatures up to 1100 °C to be reached without anvil failure. However, the cell-body temperature increased to 300 °C. A sealed vacuum-type chamber was employed to eliminate the problem with gasket and anvil oxidation. The optimized operating parameters reported here provide a routine method for high temperature-high pressure studies. The method was used to densify and sinter nanosize amorphous silicon nitride and γ-alumina powders at high temperatures and high pressures.

  4. High pressure studies using two-stage diamond micro-anvils grown by chemical vapor deposition

    DOE PAGES

    Vohra, Yogesh K.; Samudrala, Gopi K.; Moore, Samuel L.; ...

    2015-06-10

    Ultra-high static pressures have been achieved in the laboratory using a two-stage micro-ball nanodiamond anvils as well as a two-stage micro-paired diamond anvils machined using a focused ion-beam system. The two-stage diamond anvils’ designs implemented thus far suffer from a limitation of one diamond anvil sliding past another anvil at extreme conditions. We describe a new method of fabricating two-stage diamond micro-anvils using a tungsten mask on a standard diamond anvil followed by microwave plasma chemical vapor deposition (CVD) homoepitaxial diamond growth. A prototype two stage diamond anvil with 300 μm culet and with a CVD diamond second stage ofmore » 50 μm in diameter was fabricated. We have carried out preliminary high pressure X-ray diffraction studies on a sample of rare-earth metal lutetium sample with a copper pressure standard to 86 GPa. Furthermore, the micro-anvil grown by CVD remained intact during indentation of gasket as well as on decompression from the highest pressure of 86 GPa.« less

  5. Characteristics of Moho transition zone: MCS reflection records and petrological aspects and physical properties

    NASA Astrophysics Data System (ADS)

    Kasahara, J.; Tsuruga, K.; Ike, T.; Unou, S.; Koda, K.

    2008-12-01

    The Moho is defined as the seismological discontinuity at the crust and mantle boundary. Its global depth, thickness of transition zone, and velocity structure has not been studied well. It is also poorly known whether the Moho has the same petrological and seismological properties in the continent and in the ocean, or not. Previous studies propose several petrological models for the Moho: 1) phase transition boundary from basalt to eclogite, and 2) material boundary of mafic and ultramafic rocks. By the petrological observation in the Oman ophiolite, the oceanic crust is modeled as 3) diabase-homogeneous gabbro - layered gabbro - Moho transition layer - harzburgite. The thickness of Moho transition zone (MTZ), at the boundary between Earth's crust and the subjacent mantle, has significant effect on the seismic responses from the Moho. We examined seismic characteristics of Moho reflection (hereafter PmP) using MCS (Multi Channel Seismic) reflection records obtained by high quality seismic experiments in the western Pacific by JOGMEC (Japan Oil, Gas and MEtals national Corporation). The MCS records show clear reflections at ~ 6-10 km in depth from the ocean bottom in the north and south of Ogasawara Plateau. However, considering horizontal variation in the PmP intensity, the nature of the MTZ varies from place to place. In the seismic profile D00-D, across Ogasawara Plateau in the N-S direction, the PmP abruptly disappears far from the nearby seamount where the overlain sedimentary section has less change. In another case, shown in D00-C that is located 130km west of D00-D, the PmP clearly shows high-amplitude continuous reflection near the seamount's flank. Data acquisition is relatively constant for the Ogasawara MCS reflection lines; therefore, the difference in the PmP intensity between D00- D and D00-C may relate to the nature of the Moho. The comparison of reflection records and synthetic waveforms calculated by Tsuruga et al.(this meeting) shows that if the

  6. Experimental Design for Laser Produced Shocks in Diamond Anvil Cells

    SciTech Connect

    Moon, S J; Cauble, R; Collins, G W; Celliers, P M; Hicks, D; Da Silva, L B; Mackinon, A; Wallace, R; Hammel, B; Hsing, W; Jeanloz, R; Lee, K M; Benedetti, L R; Koenig, M; Benuzzi, A; Huser, G; Henry, E; Batani, D; Willi, O; Pasley, J; Henning, G; Loubeyre, P; Neely, D; Notley, M; Danson, C

    2001-06-22

    Laser driven shock measurements have been performed on pre-compressed samples. A diamond anvil cell (DAC) has been used to statically compress water to 1 GPa and then strong shocked with an energetic laser. The use of intense laser irradiation can drive shocks in targets making it possible to study the equation of state (EOS) of samples well into the hundreds of GPQ regime. Generally, such experiments employ a sample initially at normal density and standard pressure. Therefore providing data on the principal Hugoniot. In this experiment the initial state of the sample was varied to provide data off the principal Hugoniot. We report the work that was done on the Vulcan laser and describe a method to achieve off principal Hugoniot data.

  7. Hydrostaticity of Pressure Media in Diamond Anvil Cells

    NASA Astrophysics Data System (ADS)

    You, Shu-Jie; Chen, Liang-Chen; Jin, Chang-Qing

    2009-09-01

    Hydrostaticity under high pressure of several materials from solid, fluid to gas, which are widely used as pressure media in modern high-pressure experiments, is investigated in diamond anvil cells. Judging from the R-line widths and R1 - R2 peak separation of Ruby fluorescence, the inert argon gas is hydrostatic up to about 30 GPa. The behavior of silicon oil is found to be similar to argon at pressures less than 10 GPa, while the widening of R-lines and increase of R1 - R2 peak separation at higher pressure loads indicate a significant degradation of hydrostaticity. Therefore silicon oil is considered as a good pressure medium at pressures less than 10 GPa but poor at higher pressures.

  8. Reactivity pattern of 'myeloid monoclonal antibodies' with emphasis on MCS-2.

    PubMed

    Drexler, H G; Sagawa, K; Menon, M; Minowada, J

    1986-01-01

    The reactivity pattern of the murine monoclonal antibody (MoAb) MCS-2 was tested on a panel of 724 cases of leukemia-lymphoma. MCS-2 was positive in 178/185 (96%) cases of AML (FAB M1-3), 10/10 cases of AMMol/AMoL (FAB M4/5), 42/45 (93%) cases of CML, 1/1 case of CMoL, 37/38 (97%) cases of CML-myeloid blast crisis, 0/9 cases of CML-lymphoid blast crisis. No positive staining was seen in 238 cases of T-CLL, mycosis fungoides, Sèzary-syndrome, B-CLL, hairy cell leukemia, multiple myeloma and T- and B-lymphoma nor in 32 cases of B-ALL, Burkitt-lymphoma, Null-ALL and immature T-lymphoma. A positive expression was found in 8/110 cases of cALL, 1/6 cases of pre B-ALL and 1/35 cases of T-ALL. Fifteen other MoAbs (MCS-1, OKM1, My-1, Leu-M1, Leu-M3, CA-2-38, MY4, MY7, MY8, MY9, VIM-D2, VIM-D5, Mol, Mo2, 63D3) which are associated with the myelomonocytic cell lineages were tested by indirect immunofluorescence on 60 or more patients (62-149 cases). A wide variability in the frequency of positivity was seen for the panel of cases studied and for the blast cell populations per individual samples: 21-96% of the AML cases (FAB M1-3) and 31-100% of the AMMoL/AMoL cases (FAB M4/5) were positive for the various MoAbs. None of the analysed MoAbs stained only myelocytic or only monocytic leukemias, but a certain degree of preference for the monocytic variants was noted for Leu-M3, CA-2-38, MY4, VIM-D2, Mo2 and 63D3. The detection of MCS-2 on immature ALL blast cells might indicate a coexpression of lymphoid and myeloid markers on very immature cells, or an abnormal gene expression by malignant cells, or the identification of a so far undetected subclass of acute leukemias.

  9. Does Aerosol Loading in a Convective Environment Influence Cirrus Anvil Properties?

    NASA Astrophysics Data System (ADS)

    Berry, E.; Mace, G. G.

    2011-12-01

    Aerosol indirect effects on convection remain highly uncertain, giving conflicting results that aerosols can either invigorate or weaken convective cloud growth depending on the specifics of the case being simulated. Morrison and Grabowski (2011) performed model simulations investigating the aerosol indirect effects on tropical convection and found that anvils in polluted environments tend to have smaller ice particle sizes and smaller mass-weighted fall velocities compared to simulations in pristine environments. This implies, all else being the same, that anvils would have longer lifetimes in polluted environments. This would modify the radiative heating structure of the troposphere and could have significant feedbacks to the system. Using a multi-platform approach, we investigate whether measurements can provide any information regarding such effects. A-Train, geostationary satellite and reanalysis data are used. We present a case study of anvils produced in similar meteorological conditions but in different aerosol conditions. The anvils are defined as clean or polluted based on the MODIS aerosol retrieval products and the large-scale meteorology is characterized with the ERA-Interim. The microphysical properties are retrieved with the combined CloudSat/CALIPSO 2C-ICE product. Using geostationary satellite data, we track the cirrus anvils in time by following patterns in the water vapor imagery. This allows us to determine the rate at which the anvils are developing/dissipating, providing information on the evolution of the anvils. Such case study approaches will be used to guide further research that will be more statistically based.

  10. A new type of anvil in the Acheulian of Gesher Benot Ya‘aqov, Israel

    PubMed Central

    Goren-Inbar, Naama; Sharon, Gonen; Alperson-Afil, Nira; Herzlinger, Gadi

    2015-01-01

    We report here on the identification and characterization of thin basalt anvils, a newly discovered component of the Acheulian lithic inventory of Gesher Benot Ya‘aqov (GBY). These tools are an addition to the array of percussive tools (percussors, pitted stones and anvils) made of basalt, flint and limestone. The thin anvils were selected from particularly compact, horizontally fissured zones of basalt flows. This type of fissuring produces a natural geometry of thick and thin slabs. Hominins at GBY had multiple acquisition strategies, including the selection of thick slabs for the production of giant cores and cobbles for percussors. The selection of thin slabs was carried out according to yet another independent and targeted plan. The thinness of the anvils dictated a particular range of functions. The use of the anvils is well documented on their surfaces and edges. Two main types of damage are identified: those resulting from activities carried out on the surfaces of the anvils and those resulting from unintentional forceful blows (accidents de travaille). Percussive activities that may have been associated with the thin anvils include nut cracking and the processing of meat and bones, as well as plants. PMID:26483531

  11. Wild capuchin monkeys (Cebus libidinosus) use anvils and stone pounding tools.

    PubMed

    Fragaszy, Dorothy; Izar, Patrícia; Visalberghi, Elisabetta; Ottoni, Eduardo B; de Oliveira, Marino Gomes

    2004-12-01

    We conducted an exploratory investigation in an area where nut-cracking by wild capuchin monkeys is common knowledge among local residents. In addition to observing male and female capuchin monkeys using stones to pound open nuts on stone "anvils," we surveyed the surrounding area and found physical evidence that monkeys cracked nuts on rock outcrops, boulders, and logs (collectively termed anvils). Anvils, which were identified by numerous shallow depressions on the upper surface, the presence of palm shells and debris, and the presence of loose stones of an appropriate size to pound nuts, were present even on the tops of mesas. The stones used to crack nuts can weigh >1 kg, and are remarkably heavy for monkeys that weigh <4 kg. The abundance of shell remains and depressions in the anvil surface at numerous anvil sites indicate that nut-cracking activity is common and long-enduring. Many of the stones found on anvils (presumably used to pound nuts) are river pebbles that are not present in the local area we surveyed (except on or near the anvils); therefore, we surmise that they were transported to the anvil sites. Ecologically and behaviorally, nut-cracking by capuchins appears to have strong parallels to nut-cracking by wild chimpanzees. The presence of abundant anvil sites, limited alternative food resources, abundance of palms, and the habit of the palms in this region to produce fruit at ground level all likely contribute to the monkeys' routine exploitation of palm nuts via cracking them with stones. This discovery provides a new reference point for discussions regarding the evolution of tool use and material culture in primates. Routine tool use to exploit keystone food resources is not restricted to living great apes and ancestral hominids.

  12. Effect of Mirasol pathogen reduction technology system on in vitro quality of MCS+ apheresis platelets.

    PubMed

    Mastroianni, Maria Adele; Llohn, Abid Hussain; Akkök, Çiğdem Akalın; Skogheim, Ruby; Ødegaard, Elna Rathe; Nybruket, Monica Jenssen; Flesland, Annika; Mousavi, Seyed Ali

    2013-10-01

    Reducing the risk of pathogen transmission to transfusion recipients is one of the great concerns in transfusion medicine. Important among the measures suggested to minimise pathogen transmission is pathogen reduction technology (PRT) systems. The present study examined the effects of Mirasol PRT system on MCS+ apheresis platelets in vitro quality measures during a seven-day storage period at 22°C. Statistical analysis indicated no significant difference in platelet concentrations between the control and treated platelet concentrates (PCs) during the storage period. Glucose and lactate levels were measured to determine metabolic activities of control and treated platelets. In both control and treated platelets, the amount of glucose consumed and lactate produced increased significantly with storage time, but glucose consumption and lactate production rates were significantly higher in treated platelets compared with control platelets. The mean pH of treated PCs was decreased at all time points relative to control PCs but remained within acceptable limits. The expression of P-selectin was also higher in Mirasol PRT treated platelets throughout the storage period, but differences were not statistically significant on Days 1 and 4. Finally, visual inspection of swirling indicated that Mirasol PRT treatment of platelets is associated with platelet shape change. Overall, our results show that MCS+ apheresis platelets treated with Mirasol PRT can preserve adequate in vitro properties for at least 5 days of storage.

  13. Effectiveness of the haemonetics MCS cell separator in the collection of apheresis platelets.

    PubMed

    Keklik, Muzaffer; Keklik, Ertugrul; Korkmaz, Serdal; Aygun, Bilal; Arik, Ferhat; Kilic, Ozcan; Sarikoc, Murat

    2015-12-01

    Platelet (PLT) transfusions play an important role in patients with thrombocytopenia or severely impaired platelet function. Platelet concentrates are prepared from whole-blood donations or by plateletpheresis. In recent years, different instruments have been developed to perform plateletpheresis. We evaluated an apheresis instrument, the Haemonetics MCS(®) + with regard to PLT yield, collection efficiency (CE), and collection rate (CR) in a retrospective, randomized study in 526 donors. In this system, we used leukoreduction filters post collection to obtain leukoreduced products. The Haemonetics MCS(®) + cell separator efficiently collected apheresis platelets with median PLT yields of 3.7 × 10(11), mean CE of 66.69 ± 13.73% and mean CR of 0.063 ± 0.013 × 10(11)/min. The median blood volume processed was 3290 (2420-4370) ml, and the median volume of acid citrate dextrose-A (ACD-A) used in collections on the device was 385 (196-517) ml. Also, this device allowed the collection of white blood cell (WBC) reduced plateletpheresis with mean 0.07 ± 0.15 × 10(6) WBC content. No serious donor or recipient reactions occurred.

  14. Limb Retrievals of TES solarband/IR data (and MCS solarband data)

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Pankine, A.

    2016-12-01

    Vertical variations in aerosol distributions (and their microphysicalproperties) can have a dramatic impact on the state and evolution of theMartian atmosphere. This has been clearly delineated recent work usingretrieval products produced by the Mars Climate Sounder (MCS) teamfrom limb observations by the MCS IR bolometers. However, similarproducts for Thermal EmissionSpectrometer (TES) limb observationshave not been as widely disseminated. In addition, the solar bandchannels of both datasets have been essentially unanalyzed. Ouroverarching goal has been to fill these gaps in order to addressparticle size studies, as well as to generate products that can beused by the wider community. In our presentation we will include: 1) A summary of our limb radiative transfer algorithms and retrievalscheme; 2) The limitations imposed by "Smoothing Error" and by systematicradiometric error on retrievals in lower and upper atmosphere, respectively;3) vertical profiles of opacity and particle size associated with theevolution of the 2001 TES dust storm; and 4) the use of limbretrievals to estimate integrated-column optical depths (validatedagainst Mars Exploration Rover and TES emission phase functionmeasurements); and 5) the plans for an ongoing archive to be used forthe distribution of the derived profiles and associated retrievalmetadata. This work has been supported by NASA with a Mars Data AnalysisProgram award (grant NNX10AO23G).

  15. Evidence for the predominance of mid-tropopheric aerosols as subtropical anvil nuclei

    SciTech Connect

    Fridland, A; Ackermann, A; Jensen, E; Stevens, D

    2004-04-26

    NASA's recent CRYSTAL-FACE field experiment focused on anvil cirrus clouds, an important but poorly understood element of our climate system. Data obtained include the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Coupling these new measurements with detailed cloud simulations that resolve the size distributions of aerosols and cloud particles, we find several lines of evidence that most anvil crystals form on mid-tropospheric rather than boundary layer aerosols. This result defies conventional wisdom and indicates that distant pollution sources may impact anvil clouds more than local sources.

  16. A high pressure optical cell utilizing single crystal cubic zirconia anvil windows

    NASA Astrophysics Data System (ADS)

    Russell, T. P.; Piermarini, G. J.

    1997-04-01

    A high pressure optical cell capable of producing pressures up to 13.2 GPa using gem-cut single crystal cubic zirconia (CZ) anvils was developed. Maximum pressures obtainable were found to depend upon the particular pressure transmitting medium and gasket material employed. The cubic zirconia anvil high pressure cell (CZAC) provides advantages over the diamond anvil cell in optical and infrared spectroscopy while still maintaining a substantial pressure capability. To demonstrate these advantages, microRaman, optical fluorescence, and infrared absorption measurements were made on diamond, ruby, and 1,3,5-trinitrohexahydro-1,3,5-triazine samples, respectively, using the CZAC cell under high pressure conditions.

  17. An apparatus to load gaseous materials to the diamond-anvil cell

    NASA Astrophysics Data System (ADS)

    Yagi, Takehiko; Yusa, Hitoshi; Yamakata, Masa-aki

    1996-08-01

    An apparatus to load gases to the sample chamber of the diamond-anvil cell has been devised. The apparatus is driven by a conventional 50 ton hydraulic press and no gas compressor is required. The gas from a commercial gas bomb is compressed to 150 MPa and loaded into the diamond-anvil cell sample chamber. After loading, the pressure of the diamond-anvil cell is increased further using the lever and spring mechanism. This kind of gas loading apparatus will become indispensable not only for studying gaseous materials themselves, but also for making precision measurements at high pressures and high temperatures under hydrostatic conditions.

  18. High-pressure generation using double stage micro-paired diamond anvils shaped by focused ion beam

    SciTech Connect

    Sakai, Takeshi Ohfuji, Hiroaki; Yagi, Takehiko; Irifune, Tetsuo; Ohishi, Yasuo; Hirao, Naohisa; Suzuki, Yuya; Kuroda, Yasushi; Asakawa, Takayuki; Kanemura, Takashi

    2015-03-15

    Micron-sized diamond anvils with a 3 μm culet were successfully processed using a focused ion beam (FIB) system and the generation of high pressures was confirmed using the double stage diamond anvil cell technique. The difficulty of aligning two second-stage micro-anvils was solved via the paired micro-anvil method. Micro-manufacturing using a FIB system enables us to control anvil shape, process any materials, including nano-polycrystalline diamond and single crystal diamond, and assemble the sample exactly in a very small space between the second-stage anvils. This method is highly reproducible. High pressures over 300 GPa were achieved, and the pressure distribution around the micro-anvil culet was evaluated by using a well-focused synchrotron micro-X-ray beam.

  19. Nanocrystalline diamond micro-anvil grown on single crystal diamond as a generator of ultra-high pressures

    NASA Astrophysics Data System (ADS)

    Samudrala, Gopi K.; Moore, Samuel L.; Velisavljevic, Nenad; Tsoi, Georgiy M.; Baker, Paul A.; Vohra, Yogesh K.

    2016-09-01

    By combining mask-less lithography and chemical vapor deposition (CVD) techniques, a novel two-stage diamond anvil has been fabricated. A nanocrystalline diamond (NCD) micro-anvil 30 μ m in diameter was grown at the center of a [100]-oriented, diamond anvil by utilizing microwave plasma CVD method. The NCD micro-anvil has a diamond grain size of 115 nm and micro-focused Raman and X-ray Photoelectron spectroscopy analysis indicate sp3-bonded diamond content of 72%. These CVD grown NCD micro-anvils were tested in an opposed anvil configuration and the transition metals osmium and tungsten were compressed to high pressures of 264 GPa in a diamond anvil cell.

  20. KH-10-5 High-Resolution MCS Survey Off Northwest Sumatra

    NASA Astrophysics Data System (ADS)

    Hirata, K.; Rahardiawan, R.; Misawa, A.; Udrekh, U.; Seeber, L.; Baba, H.; Adachi, K.; Sarukawa, H.; Kinoshita, M.; Fujiwara, T.; Arai, K.; Tokuyama, H.; Nakamura, Y.; Permana, H.; Djajadihardja, Y. S.

    2011-12-01

    A huge ocean-wide tsunami, with average heights of more than 20 meters along the west coast of the northern tip of Sumatra followed the 2004 Sumatra-Andaman earthquake (Mw9.2). Several working hypotheses have been proposed, but the generation mechanism for this tsunami remains unresolved. Most of these hypotheses suggest a possible coseismic slip on splay faults in the outer-arc-high off northwest Sumatra [e.g., Sibuet et al., 2007]. Among these splay faults, the Middle Thrust (or possibly the Lower Thrust), can best account for features of the Indian Ocean tsunamis observed at regional and ocean-wide distances [Hirata et al., 2008]. To map geological structures that may be contributed by splay fault displacements, we surveyed bathymetry offshore northern Sumatra in 2009. The aim of that survey was to identify a fault trace that could be considered a candidate for the Middle Thrust. In 2010, we have conducted KH-10-5 high-resolution MCS survey of the likely source region for the tsunami with JAMSTEC R/V Hakuho-Maru. The specification of the MCS survey are; GI-gun, G=45 cuin and I=105 cuin; every 10 sec shooting; a 1,200 m-long, 48 channel solid streamer cable.; ship speed 4 knots. We designed the acoustic survey lines to cross a series of ridges and troughs parallel to the local trench axis and hence to sample fault traces that are candidates of the Main Thrust, the Lower Thrust, the Middle Thrust, the Upper Thrust in the outer-arc high. Approx. 480 n.m. long of MCS data were acquired during the cruise. We could obtain clear images down to about 1.5 sec (TWT) in the trench fill and a maximum of about 1 sec (TWT) in small troughs in the outer-arc high. In Lines 5 and 6, a kink folding and landward vergent backthrusts were identified near the trench. Many of the small basins on the outer-arc high show deformed sediment layer structures, indicating either folding or faulting. Many SBP profiles also show deformation pattern in the uppermost sediment layers that are

  1. Arctic Ocean Sedimentary Cover Structure, Based on 2D MCS Seismic Data.

    NASA Astrophysics Data System (ADS)

    Kireev, A.; Kaminsky, V.; Poselov, V.; Poselova, L.; Kaminsky, D.

    2016-12-01

    In 2016 the Russian Federation has submitted its partial revised Submission for establishment of the OLCS (outer limit of the continental shelf) in the Arctic Ocean. In order to prepare the Submission, in 2005 - 2014 the Russian organizations carried out a wide range of geological and geophysical studies, so that today over 23000 km of MCS lines and 4000 km of deep seismic sounding are accomplished. For correct time/depth conversion of seismic sections obtained with a short streamer in difficult ice conditions wide-angle reflection/refraction seismic sonobuoy soundings were used. All of these seismic data were used to refine the stratigraphy model, to identify sedimentary complexes and to estimate the total thickness of the sedimentary cover. Seismic stratigraphy model was successively determined for the Cenozoic and pre-Cenozoic parts of the sedimentary section and was based on correlation of the Russian MCS data and seismic data documented by boreholes. Cenozoic part of the sedimentary cover is based on correlation of the Russian MCS data and AWI91090 section calibrated by ACEX-2004 boreholes on the Lomonosov Ridge for Amerasia basin and by correlation of onlap contacts onto oceanic crust with defined magnetic anomalies for Eurasia basin. Pre-Cenozoic part of the sedimentary cover is based on tracing major unconformities from boreholes on the Chukchi shelf (Crackerjack, Klondike, Popcorn) to the North-Chuckchi Trough and further to the Mendeleev Rise as well as to the Vilkitsky Trough and the adjacent Podvodnikov Basin. Six main unconformities were traced: regional unconformity (RU), Eocene unconformity (EoU) (for Eurasia basin only), post-Campanian unconformity (pCU), Brookian (BU - base of the Lower Brookian unit), Lower Cretaceous (LCU) and Jurassic (JU - top of the Upper Ellesmerian unit). The final step in our research was to generalize all seismic surveys (top of acoustic basement correlation data) and bathymetry data in the sedimentary cover thickness map

  2. Evidence for the predominance of mid-tropospheric aerosols as subtropical anvil cloud nuclei.

    PubMed

    Fridlind, Ann M; Ackerman, Andrew S; Jensen, Eric J; Heymsfield, Andrew J; Poellot, Michael R; Stevens, David E; Wang, Donghai; Miloshevich, Larry M; Baumgardner, Darrel; Lawson, R Paul; Wilson, James C; Flagan, Richard C; Seinfeld, John H; Jonsson, Haflidi H; VanReken, Timothy M; Varutbangkul, Varuntida; Rissman, Tracey A

    2004-04-30

    NASA's recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment focused on anvil cirrus clouds, an important but poorly understood element of our climate system. The data obtained included the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Coupling these new measurements with detailed cloud simulations that resolve the size distributions of aerosols and cloud particles, we found several lines of evidence indicating that most anvil crystals form on mid-tropospheric rather than boundary-layer aerosols. This result defies conventional wisdom and suggests that distant pollution sources may have a greater effect on anvil clouds than do local sources.

  3. Composite ceramic anvil cell for high-pressure magnetic properties measurements

    NASA Astrophysics Data System (ADS)

    Narayanaswamy, Suresh; Tallon, Jeff

    2013-06-01

    A ceramic-anvil based non-magnetic high-pressure cell has been developed for the magnetic properties measurement system (SQUID). The purpose of the development of this new cell is to undertake high-pressure measurements on samples like spin-crossover compounds, and antiferromagnetic materials with very weak magnetization beyond the existing capability of 1.2 GPa1. This new design is a combination of the diamond anvil cell (DAC) and piston-cylinder cell but very simplified by removing the laborious anvil-alignment procedure and making it user-friendly. A maximum pressure of 5 GPa was attained with this new cell using a 1.0 mm diameter culet composite anvils and a pre-indented CuBe gasket. We report the results of the magnetization on the CaFe2As2 single crystal sample using this new pressure-cell. Research Support: The Marsden Fund

  4. Users Guide for the Anvil Threat Corridor Forecast Tool V1.7.0 for AWIPS

    NASA Technical Reports Server (NTRS)

    Bauman, William H., III

    2007-01-01

    The Applied Meteorology Unit (AMU) originally developed the Anvil Threat Sector Tool for the Meteorological Interactive Data Display System (MIDDS) and delivered the capability in three phases beginning with a feasibility study in 2000 and delivering the operational final product in December 2003. This tool is currently used operationally by the 45th Weather Squadron (45 WS) Launch Weather Officers (LWO) and Spaceflight Meteorology Group (SMG) forecasters. Phase I of the task established the technical feasibility of developing an objective, observations-based tool for short-range anvil forecasting. The AMU was subsequently tasked to develop short-term anvil forecasting tools to improve predictions of the threat of triggered lightning to space launch and landing vehicles. Under the Phase II effort, the AMU developed a nowcasting anvil threat sector tool, which provided the user with a threat sector based on the most current radiosonde upper wind data from a co-located or upstream station. The Phase II Anvil Threat Sector Tool computes the average wind speed and direction in the layer between 300 and 150 mb from the latest radiosonde for a user-designated station. The following threat sector properties are consistent with the propagation and lifetime characteristics of thunderstorm anvil clouds observed over Florida and its coastal waters (Short et al. 2002): a) 20 n mi standoff circle, b) 30 degree sector width, c) Orientation given by 300 to 150 mb average wind direction, d) 1-, 2-, and 3- hour arcs in upwind direction, and e) Arc distances given by 300 to 150 mb average wind speed. Figure 1 is an example of the MIDDS Anvil Threat Sector tool overlaid on a visible satellite image at 2132 UTC 13 May 2001. Space Launch Complex 39A was selected as the center point and the Anvil Threat Sector was determined from upper-level wind data at 1500 UTC in the preconvective environment. Narrow thunderstorm anvil clouds extend from central Florida to the space launch and

  5. Implementation of micro-ball nanodiamond anvils for high-pressure studies above 6Mbar

    NASA Astrophysics Data System (ADS)

    Dubrovinsky, Leonid; Dubrovinskaia, Natalia; Prakapenka, Vitali B.; Abakumov, Artem M.

    2012-10-01

    Since invention of the diamond anvil cell technique in the late 1950s for studying materials at extreme conditions, the maximum static pressure generated so far at room temperature was reported to be about 400GPa. Here we show that use of micro-semi-balls made of nanodiamond as second-stage anvils in conventional diamond anvil cells drastically extends the achievable pressure range in static compression experiments to above 600GPa. Micro-anvils (10-50μm in diameter) of superhard nanodiamond (with a grain size below ~50nm) were synthesized in a large volume press using a newly developed technique. In our pilot experiments on rhenium and gold we have studied the equation of state of rhenium at pressures up to 640GPa and demonstrated the feasibility and crucial necessity of the in situ ultra high-pressure measurements for accurate determination of material properties at extreme conditions.

  6. Suppression of proatherogenic leukocyte interactions by MCS-18--Impact on advanced atherosclerosis in ApoE-deficient mice.

    PubMed

    Kuehn, Constanze; Tauchi, Miyuki; Stumpf, Christian; Daniel, Christoph; Bäuerle, Tobias; Schwarz, Marc; Kerek, Franz; Steinkasserer, Alexander; Zinser, Elisabeth; Achenbach, Stephan; Dietel, Barbara

    2016-02-01

    Atherosclerosis is associated with chronic inflammatory responses of the arterial blood vessels. The previously observed protective effect of the MCS-18 substance against the initiation of atherosclerosis in a murine model was explained by its pronounced anti-inflammatory activity. Here, we investigated its impact on murine plaque progression in advanced atherosclerosis and on proatherogenic processes. ApoE-deficient mice were fed a high-fat diet for 12 weeks to induce atherosclerosis, followed by normal chow and intraperitoneal injections of either MCS-18 (500 μg, n = 10) or saline (n = 10) twice a week for another 12 weeks. Plaque size was reduced in MCS-18 treated mice compared to controls (p = 0.001), which was associated with a reduced size of the lipid core (p = 0.01). There was a decrease in apoptotic cells (p = 0.02), endothelial ICAM-1 expression (p < 0.001), and macrophage density (p = 0.01) in the MCS-18 group. In addition, human and murine dendritic cells (DCs) and human umbilical vein endothelial cells (HUVECs) were treated with MCS-18 (50-200 μg/ml) to analyze cell migration and adhesion under flow conditions. MCS-18 reduced human (p = 0.01) and murine (p = 0.006) DC migration. Furthermore, adhesion of MCS-18-treated DCs to a HUVEC monolayer was decreased (p < 0.001). Compared to controls, CD209 (p < 0.001) and CCR7 (p = 0.003) expression was decreased in MCS-18-treated DCs, while in HUVECs lower levels of ICAM-1 (p < 0.001) and of phosphorylated NF-κB-p65 (p = 0.002) were observed. Blocking of ICAM-1 reduced DC adhesion (p < 0.001). MCS-18 exhibits interesting therapeutic effects when applied in advanced murine atherosclerosis. Its antiatherogenic impact might be associated with a suppressed adhesion to the endothelium due to down-regulation of endothelial ICAM-1 expression. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Note: Simple and portable setup for loading high purity liquids in diamond anvil cell.

    PubMed

    Olejnik, Ella; Deemyad, Shanti

    2016-03-01

    Here we explain a simple and inexpensive procedure to preserve the original purity of the liquid samples during the loading process in a diamond anvil cell. The idea is to keep the sample in frozen form during the loading process while preventing the condensation of the water or other introduction of contaminants. The system can be quickly and easily assembled in a basic laboratory setup. This process can be used for loading some of the common pressure media in a diamond anvil cell.

  8. Development of Kawai-type multianvil technology using nano-polycrystalline diamond anvils

    NASA Astrophysics Data System (ADS)

    Irifune, T.; Kunimoto, T.

    2016-12-01

    Nano-polycrystalline diamond (NPD) developed at GRC, Ehime Univ., is known to be much harder than conventional sintered polycrystalline diamond (SD), and is potentially important as material for anvils for Kawai-type (6-8 type) multianvil apparatus (KMA), as well as for diamond anvil cell. We synthesized NPD rods with about 8 mm in both diameter and length using a 6000-ton press KMA (BOTCHAN-6000), which are cut by pulsed-laser to form cubes with 6 mm edge length and tested them as anvils for KMA. In situ X-ray observations were made to evaluate the produced pressures and sample images using the "6-6-8 assembly". A combination of semi-fired pyrophyllite gaskets and alumina ceramics pressure medium optimized for the NPD anvils with a truncation (TEL) of 1.0 mm yielded pressures up to 88 GPa at a press load of only 3.4 MN, which is nearly 60% higher than the pressure (56 GPa) reached using SD anvils with the identical cell assembly at the same press load. Moreover, the high X-ray transparency of NPD has enabled us to clearly see the sample image via the anvils, allowing diffraction measurements and observations of the sample shape even if the anvil gap becomes very small under such very high pressures. The use of NPD anvils should lead to new technology for mineral physics studies under the conditions of the Earth's lowermost mantle and possibly those of the core without scarifying the advantages of KMA over DAC.

  9. Note: Simple and portable setup for loading high purity liquids in diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Olejnik, Ella; Deemyad, Shanti

    2016-03-01

    Here we explain a simple and inexpensive procedure to preserve the original purity of the liquid samples during the loading process in a diamond anvil cell. The idea is to keep the sample in frozen form during the loading process while preventing the condensation of the water or other introduction of contaminants. The system can be quickly and easily assembled in a basic laboratory setup. This process can be used for loading some of the common pressure media in a diamond anvil cell.

  10. Anvil Forecast Tool in the Advanced Weather Interactive Processing System, Phase II

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III

    2008-01-01

    Meteorologists from the 45th Weather Squadron (45 WS) and Spaceflight Meteorology Group have identified anvil forecasting as one of their most challenging tasks when predicting the probability of violations of the Lightning Launch Commit Criteria and Space Light Rules. As a result, the Applied Meteorology Unit (AMU) created a graphical overlay tool for the Meteorological Interactive Data Display Systems (MIDDS) to indicate the threat of thunderstorm anvil clouds, using either observed or model forecast winds as input.

  11. EOS calculations for hydrothermal diamond anvil cell operation.

    PubMed

    Presser, Volker; Heiss, Martin; Nickel, Klaus G

    2008-08-01

    The hydrothermal diamond anvil cell (HDAC) is an excellent tool for high-temperature, high-pressure (hydrothermal) experiments. For an accurate determination of pressure induced by a certain temperature in an isochoric sample chamber volume, an equation of state (EOS) of water can be used instead of direct measurement. This paper reviews the theoretic background and provides all needed equations for the application of EOS of water to HDAC experiments summarizing state-of-the-art knowledge and incorporating up-to-date thermodynamic data. The p-T conditions determined using the IAPWS-95 formulation for the thermodynamic properties of ordinary water are in agreement with values obtained from direct methods or other established EOS formulations. In particular, (1) the calculation of density through the (a) melting point or (b) homogenization method along with determining (2) pressure as a function of density and temperature or (3) density as a function of pressure and temperature is explained. As a new aspect in the context of HDAC operations, the critical influence of nucleation and a strategy to overcome this problem are discussed. Furthermore, we have derived new polynomial equations, which allow the direct calculation of the fluid phase's density from the melting temperature. These are implemented in a spreadsheet program, which is freely available for interested users.

  12. Applications of sample nanofabrication in diamond-anvil cell experiments

    NASA Astrophysics Data System (ADS)

    Pigott, J. S.; Fischer, R. A.; Hrubiak, R.; Scott, H. P.; Panero, W. R.

    2015-12-01

    We use electron gun evaporation, sputter deposition, and photolithography to fabricate samples for laser-heated diamond anvil cell experiments. With complimentary thermal modeling, the sample geometry can be optimized and tailored to the experimental application. Here we highlight equation of state studies using nanofabricated double-hot plate samples. The homogeneous samples produced by our methods lead to exceptionally even heating both spatially and temporally that produced high-quality equations of state for nickel and stishovite. The Fe and Pt mutual equations of state may be well characterized and we show recent progress in fabricating samples consisting of a layered stack of Pt/SiO2/Fe/SiO2 in which the SiO2 serves to prevent the alloying of Fe and Pt. Finally, by exploiting state-of-the art nanofabrication techniques, we explore a wider range of the potential applications of such samples including high-pressure, high-temperature diffusion, melting, and thermal conductivity. Using the TempDAC code, we investigate the ideal sizes and ratios of the sample, heating laser diameter, and x-ray spot size while quantifying the effect of x-ray misalignment.

  13. First tests of THz transmission through a Diamond Anvil Cell

    SciTech Connect

    John Klopf

    2011-01-24

    The THz source generated by the accelerator driver for the Jefferson Lab Free Electron Laser is unique in the world in its ability to deliver a high average power beam of ultrashort (<500 fs FWHM) broadband THz pulses. The spectrum of this source presents an ideal probe for many low energy phenomena, and the time structure enables measurement of dynamic processes with sub-ps resolution. An outline of the range of potential applications for this THz source as a probe of sub-ps dynamics in materials under extreme conditions will be presented. To demonstrate the capabilities of this source for just such experiments, the first set of tests to characterize the transmission of the THz beam through a diamond anvil cell (DAC) have been performed. These preliminary results will be presented along with a description of the optical design used to deliver the THz beam into and out of the DAC. The current design will be compared with other possible techniques and the plans for the next set of measurements will also be given.

  14. Exploring the relationship between Assimilation and Fractional Crystallization of Basalts with the Magma Chamber Simulator (MCS)

    NASA Astrophysics Data System (ADS)

    Creamer, J. B.; Bohrson, W. A.; Spera, F. J.; Ghiorso, M. S.

    2010-12-01

    Assimilation of partially melted country rock into cooling and Fractionally Crystallizing magma bodies (AFC) is well known but dynamic process that has been explored by laboratory experiments and study of natural occurrences. Case studies of magmatic systems frequently invoke models that feature mass ratios of assimilation to fractional crystallization (e) that are constant. This study explores the relationship between assimilation and fractional crystallization, as affected by magma and country rock composition, water contents, and pressure using the Magma Chamber Simulator (MCS). The MCS is a computational tool that combines the framework of mass and energy conservation equations (EC-RAFC) approach of Spera and Bohrson (2001, 2002, 2003) and Bohrson and Spera (2001, 2003) with the phase equilibria modeling capabilities of MELTS (Ghiorso and Sack 1995). Using MCS results, it is found that e is often hugely dependent on even minor variations in system composition, and that e often varies systematically (usually increasing with time) during an individual instance of AFC, by up to an order of magnitude. A well-documented effect of increasing the water content of magmas is the suppression of crystallization. Indeed, among different types of basalt (Mid-Ocean Ridge Basalt MORB, High-Alumina Basalt HAB, Alkali Basalt AB), assimilation of dry gabbro (e~0.7) is less efficient than assimilation of hydrated gabbro (e~1.5-2.5). However, the effect on efficiency of assimilation, e, of magma water content, though pronounced, is more complex. Generally, however, wet magmas can yield scenarios with higher e values due to the suppression of plagioclase crystallization, which has a relatively large enthalpy of formation. The effect of higher pressure on AFC systems, all else being equal, is quite variable. For example, a MORB, HAB, or AB assimilating gabbro at 1kbar yields an e value of ~1.5. If the pressure is elevated to 5 kbar, the same systems yield an e value of ~0.3. The

  15. User Guide for the Anvil Threat Cooridor Forecast Tool V2.4 for AWIPS

    NASA Technical Reports Server (NTRS)

    Barett, Joe H., III; Bauman, William H., III

    2008-01-01

    The Anvil Tool GUI allows users to select a Data Type, toggle the map refresh on/off, place labels, and choose the Profiler Type (source of the KSC 50 MHz profiler data), the Date- Time of the data, the Center of Plot, and the Station (location of the RAOB or 50 MHz profiler). If the Data Type is Models, the user selects a Fcst Hour (forecast hour) instead of Station. There are menus for User Profiles, Circle Label Options, and Frame Label Options. Labels can be placed near the center circle of the plot and/or at a specified distance and direction from the center of the circle (Center of Plot). The default selection for the map refresh is "ON". When the user creates a new Anvil Tool map with Refresh Map "ON, the plot is automatically displayed in the AWIPS frame. If another Anvil Tool map is already displayed and the user does not change the existing map number shown at the bottom of the GUI, the new Anvil Tool map will overwrite the old one. If the user turns the Refresh Map "OFF", the new Anvil Tool map is created but not automatically displayed. The user can still display the Anvil Tool map through the Maps dropdown menu* as shown in Figure 4.

  16. A new multi-anvil press employing six independently acting 8 MN hydraulic rams

    NASA Astrophysics Data System (ADS)

    Manthilake, M. A. G. M.; Walte, N.; Frost, D. J.

    2012-06-01

    A new large volume multi-anvil system which employs six independently acting hydraulic rams with independent oil pressurization systems has been developed for high pressure and temperature experiments. The six 8 MN hydraulic rams approach at right angles inside a composite steel plate frame and can each advance a square faceted anvil of either hardened steel or tungsten carbide. The position of each anvil can be measured relative to the frame of the press to a precision of 0.1 μ m. The press is designed to perform both deformation experiments using cubic ceramic pressure media and experiments employing eight inner cubic anvils to compress an octahedral pressure medium. During compression, the position of each anvil relative to the press frame can be precisely measured and controlled independently, thus ensuring a high level of symmetry in the compressive stress environment. The highly cubic compressive regime provides an optimal environment for the use of inner sintered diamond cubic anvils, which can potentially obtain pressures above 50 GPa. The large loading capacity (24 MN) allows larger cubic pressure media to be used at higher pressures than conventional systems.

  17. Quasi-Stationary Shear-parallel MCS in a Near-saturated Environment

    NASA Astrophysics Data System (ADS)

    Liu, Changhai; Moncrieff, Mitchell

    2016-04-01

    Idealized simulations are performed to investigate a poorly-understood category of Mesoscale Convective Systems (MCSs) - quasi-stationary convective lines with upstream-building and downstream stratiform observed in very moist environments. A specific feature in the experimental design is the inclusion of a highly idealized moisture front, mimicking the water vapor variations across the large-scale quasi-stationary (Mei-Yu) front during the Asian summer monsoon, where this regime of convective organization has been frequently observed. The numerical experiment with a wind profile of significant low-level vertical shear, plus a moist thermodynamic sounding with low convective inhibition, generates a long-lasting convective system which is down-shear tilted with a morphology resembling the documented MCSs with back-building or parallel stratiform in East Asia and North America. This is the first successful simulations of the carrot-like MCS morphology, where cells initiate near the upstream edge in either back-building or forward-building form depending on the system propagation direction. A major disparity from most types of MCSs, especially the well-studied squall line, is the weak and shallow cold pool and its negligible effect on system sustenance and propagation. Instead of the cold-pool-shear interaction, it is found that convectively-excited gravity waves are responsible for the intermittent upstream initiation of convective elements. Sensitivity tests show that both the moisture front and shear are critical for this MCS category. Our study suggests that the background spatial moisture variability affects the selection of the modes of organization, and that a systematic investigation of its role in convective organization in various wind shear conditions should be explored.

  18. How well does CO emission measure the H2 mass of MCs?

    NASA Astrophysics Data System (ADS)

    Szűcs, László; Glover, Simon C. O.; Klessen, Ralf S.

    2016-07-01

    We present numerical simulations of molecular clouds (MCs) with self-consistent CO gas-phase and isotope chemistry in various environments. The simulations are post-processed with a line radiative transfer code to obtain 12CO and 13CO emission maps for the J = 1 → 0 rotational transition. The emission maps are analysed with commonly used observational methods, i.e. the 13CO column density measurement, the virial mass estimate and the so-called XCO (also CO-to-H2) conversion factor, and then the inferred quantities (i.e. mass and column density) are compared to the physical values. We generally find that most methods examined here recover the CO-emitting H2 gas mass of MCs within a factor of 2 uncertainty if the metallicity is not too low. The exception is the 13CO column density method. It is affected by chemical and optical depth issues, and it measures both the true H2 column density distribution and the molecular mass poorly. The virial mass estimate seems to work the best in the considered metallicity and radiation field strength range, even when the overall virial parameter of the cloud is above the equilibrium value. This is explained by a systematically lower virial parameter (i.e. closer to equilibrium) in the CO-emitting regions; in CO emission, clouds might seem (sub-)virial, even when, in fact, they are expanding or being dispersed. A single CO-to-H2 conversion factor appears to be a robust choice over relatively wide ranges of cloud conditions, unless the metallicity is low. The methods which try to take the metallicity dependence of the conversion factor into account tend to systematically overestimate the true cloud masses.

  19. Plasma extraction rate and collection efficiency during therapeutic plasma exchange with Spectra Optia in comparison with Haemonetics MCS+.

    PubMed

    Lambert, Catherine; Gericke, Marion; Smith, Richard; Hermans, Cedric

    2011-01-01

    For therapeutic plasma exchange (TPE), continuous and intermittent flow separators are known to be efficient. This study was undertaken to compare the performances of the Spectra Optia, a continuous flow centrifugal apheresis system recently developed by CaridianBCT, with the Haemonetics Multicomponents System (MCS)+ apheresis system based on intermittent flow centrifugation. The primary objective of the study was to compare the time required to exchange one total plasma volume with both separators. The secondary objectives were to determine the plasma exchange efficiency, the plasma extraction rate, the percentage of target exchange volume achieved, and the loss of cellular components. The study involved prospectively paired comparison of 16 TPE on each device performed in patients with chronic diseases treated with TPE. The time required to exchange 1 total plasma volume was 182 ± 36 minutes for MCS+ procedures and 100 ± 20 minutes for the Spectra Optia procedures (P < 0.05, all results presented as mean ± standard deviation). A significantly higher plasma extraction rate was achieved (30.2 ± 4.3 vs 16.8 ± 3.4 mL/min, respectively, P < 0.05), and the plasma exchange efficiency was slightly better with the Spectra Optia compared with the MCS+ procedures (83.4 ± 7.0 vs 80.0 ± 8.5%, P < 0.05). The platelet loss was significantly lower with the Spectra Optia compared with the MCS+ procedures (1.6 ± 2.3 vs 7.5 ± 4.2%, respectively, P < 0.05), whereas the red blood cells loss was comparable. In conclusion, the Spectra Optia has significantly higher extraction rate and exchange efficiency than the MCS+ allowing to remove the same amount of plasma in less time, by processing less blood. It also removes significantly less platelets than the MCS+ separator.

  20. Spectral Characteristics of Tropical Anvils Obtained by Combining TRMM Precipitation Radar with Visible and Infrared Scanner Data

    NASA Astrophysics Data System (ADS)

    Yang, Yuan-Jian; Lu, Da-Ren; Fu, Yun-Fei; Chen, Feng-Jiao; Wang, Yu

    2015-06-01

    The spectral characteristics of anvils in tropical areas (25°S-25°N) have been investigated on the basis of data from the tropical rainfall measuring mission's (TRMM) precipitation radar (PR) and a visible and infrared scanner (VIRS), from 1998 to 2007. The anvils' vertical structures were captured by TRMM PR and categorized into two subtypes: ice anvils with an echo base of ≥6 km and mixed anvils with an echo base between 3 and 6 km. Visible and infrared signals for the anvils, which are from reflectance at 0.63 and 1.6 μm (hereafter referred to as RF1 and RF2, respectively) and the equivalent brightness temperatures of a black body at 3.7, 10.8, and 12.0 μm (hereafter referred to as TB3, TB4, and TB5, respectively), were derived simultaneously by use of TRMM VIRS. The findings reveal that the normalized frequency distribution (i.e., probability density functions, PDF) of anvil tops and bases have a bimodal distribution whereas that of anvil thickness has a single-peak curve. For visible signals, the PDF distribution of RF1 (RF2) for anvils, mixed anvils, and ice anvils has an approximately symmetric distribution with a tropics-wide averages of 0.74, 072, and 0.80 (0.21, 0.21, and 0.20), respectively. It can be concluded that ice anvils are optically thicker and contain many more ice-cloud droplets at the cloud top than mixed anvils. RF1 of anvils is usually lower over land than over ocean, by ~0.1, whereas RF2 of anvils is usually higher over land than over ocean, by ~0.3. This implies that anvil clouds have thinner optical depth and their cloud tops consist of many more small ice droplets over land than over ocean. For infrared signals, TB4 is regarded as a representative channel. The PDF distribution of TB4 for anvils and mixed anvils is broad, with tropics-wide averages of 229.2 and 232 K, respectively. They contain two peaks and the secondary peak lies at a much lower value. For ice anvils, the PDF distribution of TB4 is a single-peak curve with a

  1. Electric Fields, Cloud Microphysics, and Reflectivity in Anvils of Florida Thunderstorms

    NASA Technical Reports Server (NTRS)

    Dye, J. E.; Bateman, M. G.; Christian, H. J.; Grainger, C. A.; Hall, W. D.; Krider, E. P.; Lewis, S. A.; Mach, D. M.; Merceret, F. J.; Willett, J. C.; Willis, P. T.

    2006-01-01

    A coordinated aircraft - radar project that investigated the electric fields, cloud microphysics and radar reflectivity of thunderstorm anvils near Kennedy Space Center is described. Measurements from two cases illustrate the extensive nature of the microphysics and electric field observations. As the aircraft flew from the edges of anvils into the interior, electric fields very frequently increased abruptly from approx.1 to >10 kV/m even though the particle concentrations and radar reflectivity increased smoothly. The abrupt increase in field usually occurred when the aircraft entered regions with a reflectivity of 10 to 15 dBZ. It is suggested that the abrupt increase in electric field may be because the charge advection from the storm core did not occur across the entire breadth of the anvil and was not constant in time. Screening layers were not detected near the edges of the anvils. Some long-lived anvils showed subsequent enhancement of electric field and reflectivity and growth of particles, which if localized, might be a factor in explaining the abrupt change of field in some cases. Comparisons of electric field magnitude with particle concentration or reflectivity for a combined data set that included all anvil measurements showed a threshold behavior. When the average reflectivity, such as in a 3-km cube, was less than approximately 5 dBZ, the electric field magnitude was <3 kV/m. Based on these findings, the Volume Averaged Height Integrated Radar Reflectivity (VAHIRR) is now being used by NASA, the Air Force and Federal Aviation Administration in new Lightning Launch Commit Criteria as a diagnostic for high electric fields in anvils.

  2. Observed Enhancement of Reflectivity and Electric Field in Long-Lived Florida Anvils

    NASA Technical Reports Server (NTRS)

    Dye, James E.; Willett, John C.

    2007-01-01

    A study of two long-lived Florida anvils showed that reflectivity >20 dBZ increased in area, thickness and sometimes magnitude at mid-level well downstream of the convective cores. In these same regions electric fields maintained strengths >10 kV m1 for many tens of minutes and became quite uniform over tens of kilometers. Millimetric aggregates persisted at 9 to 10 km for extended times and distances. Aggregation of ice particles enhanced by strong electric fields might have contributed to reflectivity growth in the early anvil, but is unlikely to explain observations further out in the anvil. The enhanced reflectivity and existence of small, medium and large ice particles far out into the anvil suggest that an updraft was acting, perhaps in weak convective cells formed by instability generated from the evaporation and melting of falling ice particles. We conclude that charge separation must have occurred in these anvils, perhaps at the melting level but also at higher altitudes, in order to maintain fields >10 kV m 1 at 9 to 10 km for extended periods of time over large distances. We speculate that charge separation occurred as a result of ice-ice particle collisions (without supercooled water being present) via either a non-inductive or perhaps even an inductive mechanism, given the observed broad ice particle spectra, the strong pre-existing electric fields and the many tens of minutes available for particle interactions. The observations, particularly in the early anvil, show that the charge structure in these anvils was quite complex.

  3. Observed Enhancement of Reflectivity and Electric Field in Long-Lived Florida Anvils

    NASA Technical Reports Server (NTRS)

    Dye, James E.; Willett, John C.

    2007-01-01

    A study of two long-lived Florida anvils showed that reflectivity greater than 20 dBZ increased in area, thickness and sometimes magnitude at mid-level well downstream of the convective cores. In these same regions electric fields maintained strengths greater than 10 kV m(sup -1) for many tens of minutes and became quite uniform over tens of kilometers. Millimetric aggregates persisted at 9 to 10 km for extended times and distances. Aggregation of ice particles enhanced by strong electric fields might have contributed to reflectivity growth in the early anvil, but is unlikely to explain observations further out in the anvil. The enhanced reflectivity and existence of small, medium and large ice particles far out into the anvil suggest that an updraft was acting, perhaps in weak convective cells formed by instability generated from the evaporation and melting of falling ice particles. We conclude that charge separation must have occurred in these anvils, perhaps at the melting level but also at higher altitudes, in order to maintain fields greater than 10 kV m(sup -1) at 9 to 10 km for extended periods of time over large distances. We speculate that charge separation occurred as a result of ice-ice particle collisions (without supercooled water being present) via either a noninductive or perhaps even an inductive mechanism, given the observed broad ice particle spectra, the strong pre-existing electric fields and the many tens of minutes available for particle interactions. The observations, particularly in the early anvil, show that the charge structure in these anvils was quite complex.

  4. Electric Fields, Cloud Microphysics, and Reflectivity in Anvils of Florida Thunderstorms

    NASA Technical Reports Server (NTRS)

    Dye, J. E.; Bateman, M. G.; Christian, H. J.; Defer, E.; Grainger, C. A.; Hall, W. D.; Krider, E. P.; Lewis, S. A.; Mach, D. M.; Merceret, F. J.; hide

    2007-01-01

    A coordinated aircraft - radar project that investigated the electric fields, cloud microphysics and radar reflectivity of thunderstorm anvils near Kennedy Space Center is described. Measurements from two cases illustrate the extensive nature of the microphysics and electric field observations. As the aircraft flew from the edges of anvils into the interior, electric fields very frequently increased abruptly from approximately 1 to more than 10 kV m(exp -1) even though the particle concentration and radar reflectivity increased smoothly. The abrupt increase in field usually occurred when the aircraft entered regions with a reflectivity of 10 to 15 dBZ. It is suggested that the abrupt increase in electric field may be because the charge advection from the storm core did not occur across the entire breadth of the anvil and was not constant in time. Screening layers were not detected near the edges of the anvils. Some long-lived anvils showed subsequent enhancement of electric field and reflectivity and growth of particles, which if localized, might be a factor in explaining the abrupt change of field in some cases. Comparisons of electric field magnitude with particle concentration or reflectivity for a combined data set that included all anvil measurements showed a threshold behavior. When the average reflectivity, such as in a 3-km cube, was less than approximately 5 dBZ, the electric field magnitude was les than kV m(exp -1). Based on these findings, the Volume Averaged Height Integrated Radar Reflectivity (VAHIRR) is now being used by NASA, the Air Force and Federal Aviation Administration in new Lightning Launch Commit Criteria as a diagnostic for high electric fields in anvils.

  5. Deep Seismic Imaging of the Hellenic Subduction Zone with New MCS Data of the SISMED Project

    NASA Astrophysics Data System (ADS)

    Becel, A.; Mireille, L.; Hussni, S.; Dessa, J. X.; Schenini, L.; Sachpazi, M.; Vitard, C.

    2016-12-01

    The southwestern segment of the Hellenic subduction zone has generated a M>8 tsunamigenic earthquake in the past (365 AD), the largest event ever reported in Europe, but fundamental questions remain about the deep geometry and characteristics of the interplate fault and connected splay faults in the overriding plate that might be rooted in the megathrust. In the Fall 2012, the ULYSSE seismic program acquired deep penetration multichannel seismic (MCS) and OBS refraction profiles across a 300-km-wide section of the forearc domain. MCS data were acquired with a 4.5 km-long streamer on board the R/V Le Pourquoi Pas? from the French IFREMER facilities. The two 240 km-long seismic reflection dip profiles reveal a large and rough topography of the top of the forearc crust in both the outer and inner domains, including a several km thick forearc basin. Despite the thick Messinian evaporites at shallow depths, the 11000 cu.in airgun source reveal several discontinuous arcward-dipping reflections at 15 km depth beneath the outer forearc domain that could be related to the top of the subducting oceanic crust. Unfortunately, the 4.5 km-long streamer is too short for improving their lateral continuity and getting more detailed constraints on their geometry. In the Fall 2015, we chartered the R/V Marcus Langseth equipped with unmatched seismic facilities in the European academic fleet by means of a strong mobilization of the French and American involved laboratories (Géoazur, LDEO, ISTEP, ENS-Paris, EOST, LDO, Pau Univ.) and their research agencies (CNRS, NSF, OCA, and UCA). During the SISMED survey (Seismic Imaging inveStigation in MEDiterranean Sea for deep seismogenic faults), we collected with the R/V Marcus Langseth a 210 km-long profile coincident with the eastern ULYSSE transect with the 8 km-long streamer and a 6600 cu.in tuned airgun array shot every 50 meters. The source and the streamer were towed at a depth of 12 m to maximize low frequencies and deep imaging. Here

  6. Mars Energy Spectrum studies from Assimilated MCS data using the UK MGCM

    NASA Astrophysics Data System (ADS)

    Valeanu, Alexandru; Read, Peter; Wang, Yixiong; Lewis, Stephen; Montabone, Luca; Tabataba-Vakili, Fachreddin

    2015-04-01

    Introduction The energy spectrum (ES) analysis is a renowned tool for understanding the driving mechanisms behind atmospheric turbulence (Lindborg, 1998). We aim to investigate whether energy and enstrophy inertial ranges exist in the kinetic energy spectrum (KES), and to quantify the corresponding cascades (with their ranges), and relationship with the atmospheric forcing and energy dissipation scales. The calculation of the ES from observational data is known to be highly non-trivial due to the lack of global coverage in space and time. Gage and Nastrom (1984) were the first to overcome this problem for Earth but this has not so far been attempted for Mars. Our approach is to take the sparse observational data and assimilate it using a global numerical model. We present preliminary results using the Mars Climate Sounder (MCS) retrievals and the LMD-UK Mars GCM (MGCM). This was pioneered by Lewis and Read (1999). Methodology The equations we used to calculate the Eddy and Zonal Mean kinetic energies are derived from total KES formula presented in Lindborg and Augier (2013). Hence, adding the two spectra together, we obtain the full KES spectrum as presented in their paper. For the Available Potential Energy Spectrum (APES), we have used a preliminary simplified version of the approach presented in Lindborg and Augier (2013). The Energy Spectra To date we have assimilated the MCS data at the resolution of T31 (triangular truncation), hence the ES only spans up to total wavenumber 31. This encompasses a portion of the energy inertial range, which might be expected to manifest the -3 exponential law by analogy with the Earth (Gage & Nastrom, 1984). Features: - velocities and corresponding KEs are higher with increasing height compared to Earth, - "-3" slope is restricted to ~30 km altitude, suggesting an early departure from the enstrophy inertial range, - boundary layer velocities are similar to Earth References 1. Gage and Nastrom, A Climatology of Atmospheric

  7. Note: Effective anvil size for transverse delamination test of rare-earth-Ba₂Cu₃Oy coated conductor tapes.

    PubMed

    Shin, Hyung-Seop; Gorospe, Alking B; Dedicatoria, Marlon J

    2015-10-01

    In coated conductor (CC) tapes used in magnet and coil applications, delamination due to excessive transverse tensile stresses is still one of the major issues that need considerations. Recently, several methods in evaluating the delamination strength of CC tapes are being used. In the case of anvil test, size of the anvils will be an important factor considering its applications (i.e., superconducting coil impregnation). In this study, delamination strength of CC tape was examined using different upper anvil sizes and their effects were discussed. Finally, reasonable sizes of upper anvil to be used were proposed considering the application conditions.

  8. Note: Effective anvil size for transverse delamination test of rare-earth-Ba2Cu3Oy coated conductor tapes

    NASA Astrophysics Data System (ADS)

    Shin, Hyung-Seop; Gorospe, Alking B.; Dedicatoria, Marlon J.

    2015-10-01

    In coated conductor (CC) tapes used in magnet and coil applications, delamination due to excessive transverse tensile stresses is still one of the major issues that need considerations. Recently, several methods in evaluating the delamination strength of CC tapes are being used. In the case of anvil test, size of the anvils will be an important factor considering its applications (i.e., superconducting coil impregnation). In this study, delamination strength of CC tape was examined using different upper anvil sizes and their effects were discussed. Finally, reasonable sizes of upper anvil to be used were proposed considering the application conditions.

  9. The impact of MCS models and EFAC values on the dose simulation for a proton pencil beam

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Kuan; Chiang, Bing-Hao; Lee, Chung-Chi; Tung, Chuan-Jong; Hong, Ji-Hong; Chao, Tsi-Chian

    2017-08-01

    The Multiple Coulomb Scattering (MCS) model plays an important role in accurate MC simulation, especially for small field applications. The Rossi model is used in MCNPX 2.7.0, and the Lewis model in Geant4.9.6.p02. These two models may generate very different angular and spatial distributions in small field proton dosimetry. Beside angular and spatial distributions, step size is also an important issue that causes path length effects. The Energy Fraction (EFAC) value can be used in MCNPX 2.7.0 to control step sizes of MCS. In this study, we use MCNPX 2.7.0, Geant4.9.6.p02, and one pencil beam algorithm to evaluate the effect of dose deposition because of different MCS models and different EFAC values in proton disequilibrium situation. Different MCS models agree well with each other under a proton equilibrium situation. Under proton disequilibrium situations, the MCNPX and Geant4 results, however, show a significant deviation (up to 43%). In addition, the path length effects are more significant when EFAC is equal to 0.917 and 0.94 in small field proton dosimetry, and using a 0.97 EFAC value is the best for both accuracy and efficiency

  10. View-Angle Dependent AIRS Cloud Radiances: Implication for Tropical Gravity Waves and Anvil Structures

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.; Gong, Jie

    2011-01-01

    Tropical anvil clouds play important roles in redistributing energy, water in the troposphere. Interacting with dynamics at a wide range of spatial and temporal scales, they can become organized internally and form structured cells, transporting momentum vertically and laterally. To quantify small-scale structures inside cirrus and anvils, we study view-dependence of the cloud-induced radiance from Atmospheric Infrared Sounder (AIRS) using channels near CO2 absorption line. The analysis of tropical eight-year (30degS-30degN, 2003-2010) data suggests that AIRS east-views observe 10% more anvil clouds than westviews during day (13:30 LST), whereas east-views and westviews observe equally amount of clouds at midnight (1 :30 LST). For entire tropical averages, AIRS oblique views observe more anvils than the nadir views, while the opposite is true for deep convective clouds. The dominance of cloudiness in the east-view cannot be explained by AIRS sampling and cloud microphysical differences. Tilted and banded anvil structures from convective scale to mesoscale are likely the cause of the observed view-dependent cloudiness, and gravity wave-cloud interaction is a plausible explanation for the observed structures. Effects of the tilted and banded cloud features need to be further evaluated and taken into account potentially in large-scale model parameterizations because of the vertical momentum transport through cloud wave breaking.

  11. Dependence of Cumulus Anvil Radiative Properties on Environmental Conditions in the Tropical West Pacific

    NASA Technical Reports Server (NTRS)

    Ye, B.; DelGenio, A. D.

    1999-01-01

    Areally extensive, optically thick anvil clouds associated with mesoscale convective clusters dominate the shortwave cloud forcing in the tropics and provide longwave forcing comparable to that of thin cirrus. Changes in the cover and optical thickness of tropical anvils as climate warms can regulate the sign of cloud feedback. As a prelude to the study of MMCR data from the ARM TWP sites, we analyze ISCCP-derived radiative characteristics of anvils observed in the tropical west Pacific during the TOGA-COARE IOP. Anvils with radius greater than 100 km were identified and tracked from inception to decay using the Machado-Rossow algorithm. Corresponding environmental conditions just prior to the start of the convectove event were diagnosed using the Lin-Johnson objective analysis product. Small clusters (100-200 km radius) are observed to have a broad range of optical thicknesses (10-50), while intermediate optical thickness clusters are observed to range in size from 100 km to almost 1000 km. Large-size clusters appear to be favored by strong pre-storm large scale upward motion throughout the troposphere, moist low-to-midlevel relative humidities, environments with slightly higher CAPE than those for smaller clusters, and strong front-to-rear flow. Optically thick anvils are favored in situations of strong low-level moisture convergence and strong upper-level shear.

  12. Behavior of Explosives Under Pressure in a Diamond Anvil Cell

    SciTech Connect

    Foltz, M F

    2006-06-20

    Diamond anvil cell (DAC) studies can yield information about the pressure dependence of materials and reactions under conditions comparable to shock loading. The pressure gradient across the face of the diamonds is often deliberately minimized to create uniform pressure over much of the sample and a simplified data set. To reach very high pressures (30-40 GPa), however, it may be necessary to use ''softer'', high nitrogen content diamonds that are more susceptible to bending under pressure. The resulting enhanced pressure gradient then provides a view of high-pressure behavior under anisotropic conditions similar to those found at the burn front in a bulk sample. We discuss visual observations of pressure-induced changes relative to variations in burn rate of several explosives (Triaminotrinitrobenzene, Nitromethane, CL-20) in the DAC. The burn rate behavior of both Nitromethane (NM) and Triaminotrinitrobenzene (TATB) were previously reported for pressures up to {approx}40 GPa. Nitromethane showed a near monotonic increase in burn rate to a maximum at {approx}30 GPa after which the burn rate decreased, all without color change. At higher pressures, the TATB samples had shiny (metallic) polycrystalline zones or inclusions where the pressure was highest in the sample. Around the shiny zones was a gradation of color (red to yellow) that appeared to follow the pressure gradient. The color changes are believed related to disturbances in the resonance structure of this explosive as the intermolecular separations decrease with pressure. The color and type of residue found in unvented gaskets after the burn was complete also varied with pressure. The four polymorphs of CL-20 ({alpha}, {beta}, {gamma}, {var_epsilon}-Hexanitrohexaazaisowurtzitane, HNIW) did not change color up to the highest pressure applied ({approx}30 GPa), and each polymorph demonstrated a distinctly different burn rate signature. One polymorph {beta} was so sensitive to laser ignition over a narrow

  13. Pressure calibrants in the hydrothermal diamond-anvil cell

    USGS Publications Warehouse

    Chou, I.-Ming

    2007-01-01

    Based on the equation of state of water (EOSW), experimental pressure in the hydrothermal diamond-anvil cell (HDAC) using pure water or dilute aqueous solutions as a pressure medium can be accurately determined at each measured temperature. Consequently, meaningful interpretations can be obtained for observations in the HDAC, which has been widely accepted as a versatile, modern apparatus for hydrothermal experiments. However, this is not true when other pressure media were used because there is no reliable way to determine experimental pressure other than the use of in situ pressure sensors. Most of the available pressure sensors are difficult to apply because they either require expensive facilities to perform the measurements or are unable to provide the accuracy needed for the interpretation of hydrothermal experiments. The only exception is to use the interferometric method to detect the ??-?? quartz transition, although such applications are limited to temperatures above 573??C. In this study, three pressure calibrants were calibrated for applications at lower temperatures, and they were based on visual observation of the ferroelastic phase transitions in BaTiO3 (tetragonal/cubic), Pb3(PO4)2 (monoclinic/trigonal), and PbTiO3 (tetragonal/cubic). For the phase transitions in BaTiO3 and Pb3(PO4)2, the temperature at which twinning disappears during heating was taken as the transition temperature (Ttr); the phase transition pressures (Ptr) can be calculated, respectively, from Ptr (MPa; ??3%) = 0.17 - 21.25 [(Ttr) - 115.3], and Ptr (MPa; ??2%) = 1.00 - 10.62 [(Ttr) - 180.2], where Ttr is in ??C. For the phase transition in PbTiO3, the temperature at which the movement of phase front begins (or ends) on heating (or cooling) was taken as the transition temperature (Ttr,h or Ttr,c), and the phase transition pressures on heating (Ptr,h) and cooling (Ptr,c) can be calculated from Ptr,h (MPa; ??4%) = 7021.7 - 14.235 (Ttr,h), and Ptr,c (MPa; ??4%) = 6831.3 - 14.001 (Ttr

  14. LIRAD Observations of Tropical Cirrus Clouds in MCTEX. Part II: Optical Properties and Base Cooling in Dissipating Storm Anvil Clouds(.

    NASA Astrophysics Data System (ADS)

    Platt, C. M. R.; Austin, R. T.; Young, S. A.; Heymsfield, A. J.

    2002-11-01

    During the Maritime Continent Thunderstorm Experiment (MCTEX), several decaying storm anvils were observed. The anvil clouds exhibited typical patterns of fallout and decay over a number of hours of observation. The anvil bases were initially very attenuating to lidar pulses, and continued that way until anvil breakup commenced. During that time, the anvil base reached some characteristic altitude (7 km) below which the cloud particles had evaporated fully. Some typical `tongues' of fallout below such levels also occurred. Millimeter radar showed the storm anvil cloud tops to be much higher than detected by lidar until the anvil was well dissipated.The infrared properties of the anvils were calculated. In three of the four anvils studied, the calculated emittance never exceeded 0.8-0.85. In the remaining case, the cloud emittance approached unity only in the period before the anvil had descended appreciably. Radiative transfer calculations showed that the infrared emission originated mostly from the layer between cloud base and the height at which complete attenuation of the lidar pulse occurred. However, the correct blackbody emission at cloud base could only be obtained by assuming the existence of an additional layer, situated above the first, 1.8 km deep and with a specific backscatter coefficient. The depressed values of emittance were interpreted as a cooling (below those temperatures measured by radiosonde) for some distance above anvil cloud base due to evaporation of the cloud. Typically, this cooling amounted to about 10°C, depending on the layer thickness above cloud base at which cooling was occurring. A reexamination of data taken in 1981 at Darwin, Northern Territory, Australia, indicated a similar depression in emittance in all cases of attenuating storm anvils. A simple model of ice-mass evaporation saturating the ambient air was used to approximate the observed cooling in one anvil. Millimeter radar reflectivity measurements, which also yielded

  15. [Applications of moissanite anvil cell for Raman spectroscopy under high-temperature and high-pressure].

    PubMed

    Duan, Ti-yu; Sun, Qiang; Zheng, Hai-fei

    2005-06-01

    This paper introduces the structure and the feature of moissanite anvil cell, which is composed of moissanite anvil, supporting and creating pressure system, heater system and metal gasket. Because of its high hardness, high heat conductance, low thermal expansion, good thermal stability and low price, moissanite is a good material of anvil for high-temperature and high-pressure experimental studies. With this cell, the Raman spectrum of sodium carbonate solution, sodium sulfate solution and distilled water has been in situ measured under high-temperature and high-pressure. With increasing pressure, it can be observed that the 1066 cm(-1) Raman modes of sodium carbonate solution and the 982 cm(-1) Raman modes of sodium sulfate solution shift to high wave numbers obviously. With increasing temperature, the frequency at maximum intensity shifts to high wave numbers, the full width at half-maximum intensity decreases in the Raman spectrum of water.

  16. In situ laser heating and radial synchrotron X-ray diffraction ina diamond anvil cell

    SciTech Connect

    Kunz, Martin; Caldwell, Wendel A.; Miyagi, Lowell; Wenk,Hans-Rudolf

    2007-06-29

    We report a first combination of diamond anvil cell radialx-ray diffraction with in situ laser heating. The laser-heating setup ofALS beamline 12.2.2 was modified to allow one-sided heating of a samplein a diamond anvil cell with an 80 W yttrium lithium fluoride laser whileprobing the sample with radial x-ray diffraction. The diamond anvil cellis placed with its compressional axis vertical, and perpendicular to thebeam. The laser beam is focused onto the sample from the top while thesample is probed with hard x-rays through an x-ray transparentboron-epoxy gasket. The temperature response of preferred orientation of(Fe,Mg)O is probed as a test experiment. Recrystallization was observedabove 1500 K, accompanied by a decrease in stress.

  17. Temperature distributions in the laser-heated diamond anvil cell from 3-D numerical modeling

    SciTech Connect

    Rainey, E. S. G.; Kavner, A.; Hernlund, J. W.

    2013-11-28

    We present TempDAC, a 3-D numerical model for calculating the steady-state temperature distribution for continuous wave laser-heated experiments in the diamond anvil cell. TempDAC solves the steady heat conduction equation in three dimensions over the sample chamber, gasket, and diamond anvils and includes material-, temperature-, and direction-dependent thermal conductivity, while allowing for flexible sample geometries, laser beam intensity profile, and laser absorption properties. The model has been validated against an axisymmetric analytic solution for the temperature distribution within a laser-heated sample. Example calculations illustrate the importance of considering heat flow in three dimensions for the laser-heated diamond anvil cell. In particular, we show that a “flat top” input laser beam profile does not lead to a more uniform temperature distribution or flatter temperature gradients than a wide Gaussian laser beam.

  18. In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell

    SciTech Connect

    Kunz, Martin; Caldwell, Wendel A.; Miyagi, Lowell; Wenk, Hans-Rudolf

    2007-06-15

    We report a first combination of diamond anvil cell radial x-ray diffraction with in situ laser heating. The laser-heating setup of ALS beamline 12.2.2 was modified to allow one-sided heating of a sample in a diamond anvil cell with an 80 W yttrium lithium fluoride laser while probing the sample with radial x-ray diffraction. The diamond anvil cell is placed with its compressional axis vertical, and perpendicular to the beam. The laser beam is focused onto the sample from the top while the sample is probed with hard x-rays through an x-ray transparent boron-epoxy gasket. The temperature response of preferred orientation of (Fe,Mg)O is probed as a test experiment. Recrystallization was observed above 1500 K, accompanied by a decrease in stress.

  19. In situ laser heating and radial synchrotron x-ray diffraction in a diamond anvil cell.

    PubMed

    Kunz, Martin; Caldwell, Wendel A; Miyagi, Lowell; Wenk, Hans-Rudolf

    2007-06-01

    We report a first combination of diamond anvil cell radial x-ray diffraction with in situ laser heating. The laser-heating setup of ALS beamline 12.2.2 was modified to allow one-sided heating of a sample in a diamond anvil cell with an 80 W yttrium lithium fluoride laser while probing the sample with radial x-ray diffraction. The diamond anvil cell is placed with its compressional axis vertical, and perpendicular to the beam. The laser beam is focused onto the sample from the top while the sample is probed with hard x-rays through an x-ray transparent boron-epoxy gasket. The temperature response of preferred orientation of (Fe,Mg)O is probed as a test experiment. Recrystallization was observed above 1500 K, accompanied by a decrease in stress.

  20. Breakthrough in Diamond Anvil Technology: Opening the Door of the Mega-Bar World

    NASA Astrophysics Data System (ADS)

    Yagi, T.

    2011-12-01

    When people started using diamond anvil apparatus at around 1960, no one expected that this type of high-pressure apparatus becomes major tool to study the deep interior of the Earth. Because, sample chamber was very small, pressure value was quite uncertain, high-temperature experiment was difficult, and the pressure range was very limited. Most of these week points were overcame afterwards by various breakthroughs invented by many scientists. Among them, the extension of the pressure range to above one mega bar by H. K. Mao and his colleague at late 1970's was really a big milestone. Since then numerous high-pressure and high-temperature researches have started under the condition corresponding to the Earth's lower mantle and the core. In diamond anvil apparatus, the material used for anvils remain unchanged, still the pressure range was extended more than 100 times from the beginning. I would like to discuss about the key technology which made this breakthrough possible.

  1. Analysis of resistance-versus-pressure relations for the diamond indentor-anvil system

    NASA Technical Reports Server (NTRS)

    Ruoff, A. L.

    1979-01-01

    Pressures in excess of 1.4 Mbars have been attained by Ruoff and Wanagel (1977) by pressing tiny spherical diamond indentors (tip radius of 2 microns or less) against a diamond anvil. This system has been used for resistance-vs-pressure measurements as follows. A thin (200 A) coherent layer of a conductor, e.g., palladium, can be sputtered on the tip and on the anvil and electrical leads can then be attached to these at points remote from the contact area. Then a thin layer of the sample to be studied can be evaporated, sputtered, or placed on the anvil. When the indentor is pressed against the sample, the resistance changes as the pressure increases and as the contact radius increases. This paper analyzes the resistance-vs-pressure relationship for three different types of resistivity-vs-pressure behavior.

  2. Note: Moissanite backing plates for use in diamond anvil high pressure cells

    NASA Astrophysics Data System (ADS)

    Pugh, E.

    2016-03-01

    The use of moissanite (single crystal SiC) for backing plates within diamond anvil cells (DACs) has been developed. These have significant technical advantages in certain experiments. For example, moissanite is non-magnetic so is suitable for use in high magnetic fields and for magnetization experiments. Being translucent to light, including x-rays, means that openings are not required in the backing plate and as such has significant mechanical advantages and can provide enhanced scattering angles for x-ray diffraction experiments. The new backing plates have been successfully tested to over 25 GPa using diamond anvils with 0.5 mm culets.

  3. Note: Novel diamond anvil cell for electrical measurements using boron-doped metallic diamond electrodes

    SciTech Connect

    Matsumoto, R.; Sasama, Y.; Yamaguchi, T.; Takano, Y.; Fujioka, M.; Irifune, T.; Tanaka, M.; Takeya, H.

    2016-07-15

    A novel diamond anvil cell suitable for electrical transport measurements under high pressure has been developed. A boron-doped metallic diamond film was deposited as an electrode on a nano-polycrystalline diamond anvil using a microwave plasma-assisted chemical vapor deposition technique combined with electron beam lithography. The maximum pressure that can be achieved by this assembly is above 30 GPa. We report electrical transport measurements of Pb up to 8 GPa. The boron-doped metallic diamond electrodes showed no signs of degradation after repeated compression.

  4. From individual coping strategies to illness codification: the reflection of gender in social science research on multiple chemical sensitivities (MCS).

    PubMed

    Nadeau, Geneviève; Lippel, Katherine

    2014-09-10

    Emerging fields such as environmental health have been challenged, in recent years, to answer the growing methodological calls for a finer integration of sex and gender in health-related research and policy-making. Through a descriptive examination of 25 peer-reviewed social science papers published between 1996 and 2011, we explore, by examining methodological designs and theoretical standpoints, how the social sciences have integrated gender sensitivity in empirical work on Multiple Chemical Sensitivities (MCS). MCS is a "diagnosis" associated with sensitivities to chronic and low-dose chemical exposures, which remains contested in both the medical and institutional arenas, and is reported to disproportionately affect women. We highlighted important differences between papers that did integrate a gender lens and those that did not. These included characteristics of the authorship, purposes, theoretical frameworks and methodological designs of the studies. Reviewed papers that integrated gender tended to focus on the gender roles and identity of women suffering from MCS, emphasizing personal strategies of adaptation. More generally, terminological confusions in the use of sex and gender language and concepts, such as a conflation of women and gender, were observed. Although some men were included in most of the study samples reviewed, specific data relating to men was undereported in results and only one paper discussed issues specifically experienced by men suffering from MCS. Papers that overlooked gender dimensions generally addressed more systemic social issues such as the dynamics of expertise and the medical codification of MCS, from more consistently outlined theoretical frameworks. Results highlight the place for a critical, systematic and reflexive problematization of gender and for the development of methodological and theoretical tools on how to integrate gender in research designs when looking at both micro and macro social dimensions of environmental

  5. Glitch-free X-ray absorption spectrum under high pressure obtained using nano-polycrystalline diamond anvils.

    PubMed

    Ishimatsu, Naoki; Matsumoto, Ken; Maruyama, Hiroshi; Kawamura, Naomi; Mizumaki, Masaichiro; Sumiya, Hitoshi; Irifune, Tetsuo

    2012-09-01

    Nano-polycrystalline diamond (NPD) [Irifune et al. (2003), Nature (London), 421, 599] has been used to obtain a glitch-free X-ray absorption spectrum under high pressure. In the case of conventional single-crystal diamond (SCD) anvils, glitches owing to Bragg diffraction from the anvils are superimposed on X-ray absorption spectra. The glitch has long been a serious problem for high-pressure research activities using X-ray spectroscopy because of the difficulties of its complete removal. It is demonstrated that NPD is one of the best candidate materials to overcome this problem. Here a glitch-free absorption spectrum using the NPD anvils over a wide energy range is shown. The advantage and capability of NPD anvils is discussed by a comparison of the glitch map with that of SCD anvils.

  6. VizieR Online Data Catalog: CO obs. of MCs in the Extreme Outer Galaxy region (Sun+, 2017)

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Su, Y.; Zhang, S.-B.; Xu, Y.; Chen, X.-P.; Yang, J.; Jiang, Z.-B.; Fang, M.

    2017-08-01

    The observations in the Galactic range of 34.75°<=l<=45.25° and -5.25°<=b<=5.25° were conducted during 2011 November to 2015 March using the 13.7m millimeter-wavelength telescope of the Purple Mountain Observatory (PMO) in Delingha, China. The molecular lines of 12CO(J=1-0) in the upper sideband, and 13CO(J=1-0) and C18O(J=1-0) in the lower sideband were observed simultaneously. A total of 174 molecular clouds (MCs) were identified, of which 168 MCs probably lie in the Extreme Outer Galaxy (EOG) region. (3 data files).

  7. Inverse-Ray Imaging of Gas Hydrates Along a MCS/OBS Profile at the Continental Slope Offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Wang, T. K.; Chen, C.; Yang, B.; Lee, C.

    2006-12-01

    Prevalence of gas hydrates offshore SW Taiwan has been proposed due to lots of bottom-simulated reflectors (BSR) appeared on the seismic data. In this paper, we analyze a MCS/OBS profile with intensive BSR signals at the continental slope of the northern South China Sea. Firstly, MCS data with 160 channels collected by R/V Maurice-Ewing in September 1995 is re-processed through vertical velocity analysis, horizon velocity analysis, and prestack depth migration. Then, OBS data collected by the first Micro-OBS survey from NTOU team in August 2005 is analyzed through travel-time inversion of reflected and refracted arrivals for which the initial model is constructed from the MCS result. Finally, a novel technique of inverse reflected rays by considering both MCS and OBS data is applied for layer-stripping imaging of sedimentary layers. Velocity models imaged from three methods are confirmed the prevalence of BSR at 100-400 m depth below the sea floor along the whole profile. Relatively smooth sedimentary layers are observed below the lower slope of the continent whereas several mud diapers are imaged below the upper slope of the continent. Above the mud diapers, we find gas hydrates with high velocity of about 1.9-2.1 km/s and thickness of about 100 m immediately above the strong BSR. Similarly, near the mud diapers, free gas with low velocity of about 1.4-1.7 km/s and thickness of about 200 m is imaged. Migration of free gas through diapirism may result in lots of gas hydrates accumulated below the upper slope of the continent offshore SW Taiwan.

  8. Sequence and batch language programs and alarm-related ``C`` programs for the 242-A MCS. Revision 2

    SciTech Connect

    Berger, J.F.

    1995-03-01

    A Distributive Process Control system was purchased by Project B-534, ``242-A Evaporator/Crystallizer Upgrades``. This control system, called the Monitor and Control System (MCS), was installed in the 242-A Evaporator located in the 200 East Area. The purpose of the MCS is to monitor and control the Evaporator and monitor a number of alarms and other signals from various Tank Farm facilities. Applications software for the MCS was developed by the Waste Treatment Systems Engineering (WTSE) group of Westinghouse. The standard displays and alarm scheme provide for control and monitoring, but do not directly indicate the signal location or depict the overall process. To do this, WTSE developed a second alarm scheme which uses special programs, annunciator keys, and process graphics. The special programs are written in two languages; Sequence and Batch Language (SABL), and ``C`` language. The WTSE-developed alarm scheme works as described below: SABL relates signals and alarms to the annunciator keys, called SKID keys. When an alarm occurs, a SABL program causes a SKID key to flash, and if the alarm is of yellow or white priority then a ``C`` program turns on an audible horn (the D/3 system uses a different audible horn for the red priority alarms). The horn and flashing key draws the attention of the operator.

  9. Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

    DOEpatents

    Westerfield, C.L.; Morris, J.S.; Agnew, S.F.

    1997-01-14

    Diamond anvil cell is described for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear. 4 figs.

  10. Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear

    DOEpatents

    Westerfield, Curtis L.; Morris, John S.; Agnew, Stephen F.

    1997-01-01

    Diamond anvil cell for spectroscopic investigation of materials at high temperature, high pressure and shear. A cell is described which, in combination with Fourier transform IR spectroscopy, permits the spectroscopic investigation of boundary layers under conditions of high temperature, high pressure and shear.

  11. Human Motion Tracking and Glove-Based User Interfaces for Virtual Environments in ANVIL

    NASA Technical Reports Server (NTRS)

    Dumas, Joseph D., II

    2002-01-01

    The Army/NASA Virtual Innovations Laboratory (ANVIL) at Marshall Space Flight Center (MSFC) provides an environment where engineers and other personnel can investigate novel applications of computer simulation and Virtual Reality (VR) technologies. Among the many hardware and software resources in ANVIL are several high-performance Silicon Graphics computer systems and a number of commercial software packages, such as Division MockUp by Parametric Technology Corporation (PTC) and Jack by Unigraphics Solutions, Inc. These hardware and software platforms are used in conjunction with various VR peripheral I/O (input / output) devices, CAD (computer aided design) models, etc. to support the objectives of the MSFC Engineering Systems Department/Systems Engineering Support Group (ED42) by studying engineering designs, chiefly from the standpoint of human factors and ergonomics. One of the more time-consuming tasks facing ANVIL personnel involves the testing and evaluation of peripheral I/O devices and the integration of new devices with existing hardware and software platforms. Another important challenge is the development of innovative user interfaces to allow efficient, intuitive interaction between simulation users and the virtual environments they are investigating. As part of his Summer Faculty Fellowship, the author was tasked with verifying the operation of some recently acquired peripheral interface devices and developing new, easy-to-use interfaces that could be used with existing VR hardware and software to better support ANVIL projects.

  12. An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements.

    PubMed

    Shinoda, Keiji; Noguchi, Naoki

    2008-01-01

    A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells.

  13. Human Motion Tracking and Glove-Based User Interfaces for Virtual Environments in ANVIL

    NASA Technical Reports Server (NTRS)

    Dumas, Joseph D., II

    2002-01-01

    The Army/NASA Virtual Innovations Laboratory (ANVIL) at Marshall Space Flight Center (MSFC) provides an environment where engineers and other personnel can investigate novel applications of computer simulation and Virtual Reality (VR) technologies. Among the many hardware and software resources in ANVIL are several high-performance Silicon Graphics computer systems and a number of commercial software packages, such as Division MockUp by Parametric Technology Corporation (PTC) and Jack by Unigraphics Solutions, Inc. These hardware and software platforms are used in conjunction with various VR peripheral I/O (input / output) devices, CAD (computer aided design) models, etc. to support the objectives of the MSFC Engineering Systems Department/Systems Engineering Support Group (ED42) by studying engineering designs, chiefly from the standpoint of human factors and ergonomics. One of the more time-consuming tasks facing ANVIL personnel involves the testing and evaluation of peripheral I/O devices and the integration of new devices with existing hardware and software platforms. Another important challenge is the development of innovative user interfaces to allow efficient, intuitive interaction between simulation users and the virtual environments they are investigating. As part of his Summer Faculty Fellowship, the author was tasked with verifying the operation of some recently acquired peripheral interface devices and developing new, easy-to-use interfaces that could be used with existing VR hardware and software to better support ANVIL projects.

  14. Development of rotational diamond anvil cell for ultra-high pressure deformation experiments

    NASA Astrophysics Data System (ADS)

    Azuma, S.; Nomura, R.; Nakashima, Y.; Uesugi, K.; Shinmei, T.; Irifune, T.

    2016-12-01

    Development of high-pressure (static compression) experiments using a diamond anvil cell (DAC) enabled to increase pressure up to 360 GPa, corresponding conditions to inner core of the Earth (e.g., Tateno et al., 2010). On the other hand, pressure range is limited for a technical reason in high-pressure deformation experiments. Earth's interior is dominated by `dynamic' processes. Therefore, expansion of pressure range in deformation experiments is necessary to understanding the evolution of Earth's deep interior. We developed rotational diamond anvil cell (R-DAC) to conduct deformation experiments with large strain under ultra-high pressure conditions, corresponding to those of Earth's core. In this study, existing DAC is modified to give torsional deformation to sample. In the developed R-DAC, lower anvil is fixed and upper anvil can rotate to relative to the lower anvil. We deformed MgO to test this apparatus. The experimental conditions are ranging 30-135 GPa and room temperature. Starting material was grooved by FIB and the groove was deposited by Pt as strain-marker. Recovered samples were cut by FIB to observe the rotation angle of strain-marker, sample thickness, and shape of strain-marker in each cross-section. Deformation experiments were conducted also in Japan Synchrotron Radiation Research Institute (SPring-8) and 3D visualization of the internal structure of samples were performed using X-ray laminography (Nomura and Uesugi, 2016). We succeeded the deformation experiment at 135 GPa. The geometry of strain-marker in recovered samples show nearly simple shear, indicating that this apparatus allows us to investigate the deformation with large strain under ultra-high pressure conditions, corresponding to those of core-mantle boundary. The rotation angle of strain-marker in recovered samples were compared to that expected from rotation angle of upper anvil. The results show relatively good agreement, indicating no large slip between upper anvil and samples

  15. On the Importance of Small Ice Crystals in Tropical Anvil Cirrus

    NASA Technical Reports Server (NTRS)

    Jensen, E. J.; Lawson, P.; Baker, B.; Pilson, B.; Mo, Q.; Heymsfield, A. J.; Bansemer, A.; Bui, T. P.; McGill, M.; Hlavka, D.; Heymsfield, G.; Platnick, S.; Arnold, G. T.; Tanelli, S.

    2009-01-01

    In situ measurements of ice crystal concentrations and sizes made with aircraft instrumentation over the past two decades have often indicated the presence of numerous relatively small (< 50 m diameter) crystals in cirrus clouds. Further, these measurements frequently indicate that small crystals account for a large fraction of the extinction in cirrus clouds. The fact that the instruments used to make these measurements, such as the Forward Scattering Spectrometer Probe (FSSP) and the Cloud Aerosol Spectrometer (CAS), ingest ice crystals into the sample volume through inlets has led to suspicion that the indications of numerous small ]crystals could be artifacts of large ]crystal shattering on the instrument inlets. We present new aircraft measurements in anvil cirrus sampled during the Tropical Composition, Cloud, and Climate Coupling (TC4) campaign with the 2 ] Dimensional Stereo (2D ]S) probe, which detects particles as small as 10 m. The 2D ]S has detector "arms" instead of an inlet tube. Since the 2D ]S probe surfaces are much further from the sample volume than is the case for the instruments with inlets, it is expected that 2D ]S will be less susceptible to shattering artifacts. In addition, particle inter ]arrival times are used to identify and remove shattering artifacts that occur even with the 2D ]S probe. The number of shattering artifacts identified by the 2D ]S interarrival time analysis ranges from a negligible contribution to an order of magnitude or more enhancement in apparent ice concentration over the natural ice concentration, depending on the abundance of large crystals and the natural small ]crystal concentration. The 2D ]S measurements in tropical anvil cirrus suggest that natural small ]crystal concentrations are typically one to two orders of magnitude lower than those inferred from CAS. The strong correlation between the CAS/2D ]S ratio of small ]crystal concentrations and large ]crystal concentration suggests that the discrepancy is

  16. Tumor-mast cell interactions: induction of pro-tumorigenic genes and anti-tumorigenic 4-1BB in MCs in response to Lewis Lung Carcinoma.

    PubMed

    Wensman, Helena; Kamgari, Nona; Johansson, Anna; Grujic, Mirjana; Calounova, Gabriela; Lundequist, Anders; Rönnberg, Elin; Pejler, Gunnar

    2012-04-01

    Mast cells (MCs) can have either detrimental or beneficial effects on malignant processes but the underlying mechanisms are poorly understood. Here we addressed this issue by examining the interaction between Lewis Lung Carcinoma (LLC) cells and MCs. In vivo, LLC tumors caused a profound accumulation of MCs, suggesting that LLC tumors have the capacity to attract MCs. Indeed, transwell migration assays showed that LLC-conditioned medium had chemotactic activity towards MCs, which was blocked by an antibody towards stem cell factor. In order to gain insight into the molecular mechanisms operative in tumor-MC interactions, the effect of LLC on the MC gene expression pattern was examined. As judged by gene array analysis, conditioned medium from LLC cells caused significant upregulation of numerous cell surface receptors and a pro-angiogenic Runx2/VEGF/Dusp5 axis in MCs, the latter in line with a role for MCs in promoting tumor angiogenesis. Among the genes showing the highest extent of upregulation was Tnfrsf9, encoding the anti-tumorigenic protein 4-1BB, suggesting that also anti-tumorigenic factors are induced. Quantitative RT-PCR analysis showed that 4-1BB was upregulated in a transient manner, and it was also shown that tumor cells induce 4-1BB in human MCs. Immunohistochemical analysis showed that LLC-conditioned medium induced 4-1BB also at the protein level. Together, this study provides novel insight into the molecular events associated with MC-tumor interactions and suggests that tumor cells induce both pro- and anti-tumorigenic responses in MCs. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. On the Development of Above-Anvil Cirrus Plumes in Extratropical Convection

    NASA Astrophysics Data System (ADS)

    Homeyer, C. R.; McAuliffe, J. D.; Bedka, K. M.

    2016-12-01

    Expansive cirrus clouds present above the anvils of extratropical convection have been observed in satellite and aircraft-based imagery for several decades. Despite knowledge of their occurrence, the precise mechanisms and atmospheric conditions leading to their formation and maintenance are not entirely known. Here, we examine the formation of these cirrus "plumes" using a combination of satellite imagery, three-dimensional ground-based radar observations, assimilated atmospheric states from a state-of-the-art reanalysis, and idealized numerical simulations with explicitly resolved convection. Using data from ten recent cases (2013-Present), we find that all storms with above-anvil cirrus plumes reach altitudes 1 to 6 km above the tropopause. Thus, it is likely that these clouds represent the injection of cloud material into the lower stratosphere. Comparison of above-anvil cirrus plume cases with ten additional cases of observed tropopause-penetrating convection without plumes reveals that these clouds are associated with large vector differences between the motion of a storm and the environmental wind in the upper troposphere and lower stratosphere (UTLS), suggesting that gravity wave breaking and/or stretching of the tropopause-penetrating cloud are/is more prevalent in plume-producing storms. No relationship is found between above-anvil cirrus plume occurrence and the stability of the lower stratosphere (or tropopause structure) or the duration of stratospheric penetration. Idealized model simulations of tropopause-penetrating convection with small and large magnitudes of storm-relative wind in the UTLS are found to reproduce the established observational relationship and show that frequent gravity wave breaking is the primary mechanism responsible for above-anvil cirrus plume formation.

  18. Life Cycle of Tropical Convection and Anvil in Observations and Models

    NASA Astrophysics Data System (ADS)

    McFarlane, S. A.; Hagos, S. M.; Comstock, J. M.

    2011-12-01

    Tropical convective clouds are important elements of the hydrological cycle and produce extensive cirrus anvils that strongly affect the tropical radiative energy balance. To improve simulations of the global water and energy cycles and accurately predict both precipitation and cloud radiative feedbacks, models need to realistically simulate the lifecycle of tropical convection, including the formation and radiative properties of ice anvil clouds. By combining remote sensing datasets from precipitation and cloud radars at the Atmospheric Radiation Measurement (ARM) Darwin site with geostationary satellite data, we can develop observational understanding of the lifetime of convective systems and the links between the properties of convective systems and their associated anvil clouds. The relationships between convection and anvil in model simulations can then be compared to those seen in the observations to identify areas for improvement in the model simulations. We identify and track tropical convective systems in the Tropical Western Pacific using geostationary satellite observations. We present statistics of the tropical convective systems including size, age, and intensity and classify the lifecycle stage of each system as developing, mature, or dissipating. For systems that cross over the ARM Darwin site, information on convective intensity and anvil properties are obtained from the C-Pol precipitation radar and MMCR cloud radar, respectively, and are examined as a function of the system lifecycle. Initial results from applying the convective identification and tracking algorithm to a tropical simulation from the Weather Research and Forecasting (WRF) model run show that the model produces reasonable overall statistics of convective systems, but details of the life cycle (such as diurnal cycle, system tracks) differ from the observations. Further work will focus on the role of atmospheric temperature and moisture profiles in the model's convective life cycle.

  19. Anvil Forecast Tool in the Advanced Weather Interactive Processing System (AWIPS)

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Hood, Doris

    2009-01-01

    Launch Weather Officers (LWOs) from the 45th Weather Squadron (45 WS) and forecasters from the National Weather Service (NWS) Spaceflight Meteorology Group (SMG) have identified anvil forecasting as one of their most challenging tasks when predicting the probability of violating the Lightning Launch Commit Criteria (LLCC) (Krider et al. 2006; Space Shuttle Flight Rules (FR), NASA/JSC 2004)). As a result, the Applied Meteorology Unit (AMU) developed a tool that creates an anvil threat corridor graphic that can be overlaid on satellite imagery using the Meteorological Interactive Data Display System (MIDDS, Short and Wheeler, 2002). The tool helps forecasters estimate the locations of thunderstorm anvils at one, two, and three hours into the future. It has been used extensively in launch and landing operations by both the 45 WS and SMG. The Advanced Weather Interactive Processing System (AWIPS) is now used along with MIDDS for weather analysis and display at SMG. In Phase I of this task, SMG tasked the AMU to transition the tool from MIDDS to AWIPS (Barrett et aI., 2007). For Phase II, SMG requested the AMU make the Anvil Forecast Tool in AWIPS more configurable by creating the capability to read model gridded data from user-defined model files instead of hard-coded files. An NWS local AWIPS application called AGRID was used to accomplish this. In addition, SMG needed to be able to define the pressure levels for the model data, instead of hard-coding the bottom level as 300 mb and the top level as 150 mb. This paper describes the initial development of the Anvil Forecast Tool for MIDDS, followed by the migration of the tool to AWIPS in Phase I. It then gives a detailed presentation of the Phase II improvements to the AWIPS tool.

  20. Duration and extent of large electric fields in a thunderstorm anvil cloud after the last lightning

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Krehbiel, Paul R.

    2010-10-01

    A series of balloon electric field (E) soundings and time-correlated radar scans through the balloon locations are used to examine the evolution of charge and reflectivity inside a dissipating thunderstorm anvil. The soundings cover a 75 min period during and after the final lightning flash in distant convection. The first sounding measured large E magnitudes (maximum 65 kV m-1) and significant charge densities of both polarities (maximum +2.5 nC m-3) within and screening the anvil. Little change in the maximum E values occurred in the 30 min between the first and third soundings, although altitudes and densities of some charge regions decreased with time (maximum +0.6 nC m-3). Screening charge regions were observed in close coincidence with 12 dbZ radar reflectivity contours, and interior positive charge was found in the reflectivity maxima of both anvil decks. The fourth sounding ascended through visible but optically less dense cloud, and no enhanced E values were detected. Overall, the data indicate the interior positive charge region of the main anvil contained about 150 C and covered at least 250 km2 nearly 30 min after the last lightning flash. Potentially hazardous E values of 30-35 kV m-1 were measured at 9.9-10.2 km altitude, a common jet aircraft cruising altitude, more than 20 km away from and 32 min after the final lightning flash. About 50 min after the last flash, the main positive charge region contained an estimated 50 C, and potentially hazardous E values associated with the anvil extended over at least 220 km2.

  1. Miniature ceramic-anvil high-pressure cell for magnetic measurements in a commercial superconducting quantum interference device magnetometer

    NASA Astrophysics Data System (ADS)

    Tateiwa, Naoyuki; Haga, Yoshinori; Fisk, Zachary; Ōnuki, Yoshichika

    2011-05-01

    A miniature opposed-anvil high-pressure cell has been developed for magnetic measurement in a commercial superconducting quantum interference device magnetometer. Non-magnetic anvils made of composite ceramic material were used to generate high-pressure with a Cu-Be gasket. We have examined anvils with different culet sizes (1.8, 1.6, 1.4, 1.2, 1.0, 0.8, and 0.6 mm). The pressure generated at low temperature was determined by the pressure dependence of the superconducting transition of lead (Pb). The maximum pressure Pmax depends on the culet size of the anvil: the values of Pmax are 2.4 and 7.6 GPa for 1.8 and 0.6 mm culet anvils, respectively. We revealed that the composite ceramic anvil has potential to generate high-pressure above 5 GPa. The background magnetization of the Cu-Be gasket is generally two orders of magnitude smaller than the Ni-Cr-Al gasket for the indenter cell. The present cell can be used not only with ferromagnetic and superconducting materials with large magnetization but also with antiferromagnetic compounds with smaller magnetization. The production cost of the present pressure cell is about one tenth of that of a diamond anvil cell. The anvil alignment mechanism is not necessary in the present pressure cell because of the strong fracture toughness (6.5 MPa m1/2) of the composite ceramic anvil. The simplified pressure cell is easy-to-use for researchers who are not familiar with high-pressure technology. Representative results on the magnetization of superconducting MgB2 and antiferromagnet CePd5Al2 are reported.

  2. GhMCS1, the Cotton Orthologue of Human GRIM-19, Is a Subunit of Mitochondrial Complex I and Associated with Cotton Fibre Growth

    PubMed Central

    Dong, Chun-Juan; Wu, Ai-Min; Du, Shao-Jun; Tang, Kai; Wang, Yun; Liu, Jin-Yuan

    2016-01-01

    GRIM-19 (Gene associated with Retinoid-Interferon-induced Mortality 19) is a subunit of mitochondrial respiratory complex I in mammalian systems, and it has been demonstrated to be a multifunctional protein involved in the cell cycle, cell motility and innate immunity. However, little is known about the molecular functions of its homologues in plants. Here, we characterised GhMCS1, an orthologue of human GRIM-19 from cotton (Gossypium hirsutum L.), and found that it was essential for maintaining complex integrity and mitochondrial function in cotton. GhMCS1 was detected in various cotton tissues, with high levels expressed in developing fibres and flowers and lower levels in leaves, roots and ovules. In fibres at different developmental stages, GhMCS1 expression peaked at 5–15 days post anthesis (dpa) and then decreased at 20 dpa and diminished at 25 dpa. By Western blot analysis, GhMCS1 was observed to be localised to the mitochondria of cotton leaves and to colocalise with complex I. In Arabidopsis, GhMCS1 overexpression enhanced the assembly of complex I and thus respiratory activity, whereas the GhMCS1 homologue (At1g04630) knockdown mutants showed significantly decreased respiratory activities. Furthermore, the mutants presented with some phenotypic changes, such as smaller whole-plant architecture, poorly developed seeds and fewer trichomes. More importantly, in the cotton fibres, both the GhMCS1 transcript and protein levels were correlated with respiratory activity and fibre developmental phase. Our results suggest that GhMCS1, a functional ortholog of the human GRIM-19, is an essential subunit of mitochondrial complex I and is involved in cotton fibre development. The present data may deepen our knowledge on the potential roles of mitochondria in fibre morphogenesis. PMID:27632161

  3. Finite element analysis and design of cubic high-pressure anvils based on the principle of lateral support

    NASA Astrophysics Data System (ADS)

    Han, Qi-Gang; Li, Ming-Zhe; Jia, Xiao-Peng; Ma, Hong-An

    2010-12-01

    This article theoretically investigates the lateral support on cubic high-pressure anvil using finite element analysis. The results show that to gain the same chamber pressure, the value of system oil pressure can be decreased by reducing the lateral support area and the anvils' lifetime is extended when the lateral support area grows. The optimal lateral support area to maximize anvils' lifetime is 27.96 cm2. Furthermore, the chamber pressure will increase by about 6.99% when the value of lateral support area reduces from 33.16 to 27.96 cm2 under same hydraulic rams. Our simulation results have been verified by many high-pressure synthesis experiments and illustrated by breakage of anvils.

  4. An opposed-anvil-type apparatus with an optical window and a wide-angle aperture for neutron diffraction

    NASA Astrophysics Data System (ADS)

    Iizuka, Riko; Yagi, Takehiko; Gotou, Hirotada; Komatsu, Kazuki; Kagi, Hiroyuki

    2012-09-01

    We designed new anvil assemblies for acquiring high-quality neutron diffraction data and ruby fluorescence spectra inside a sample chamber. The conical aperture of Ni-binded WC anvils was expanded by a factor of two. A hybrid gasket made of TiZr- and Al-alloy was developed to prevent outward extrusion. A small and optically transparent window of moissanite was introduced to allow for the determination of pressure and hydrostaticity by measurement of ruby fluorescence spectra. High pressure-generation tests that make use of Bi electrical conductivity and ruby pressure markers revealed that pressure could be determined over 10 GPa. In situ synchrotron X-ray diffraction experiments were also carried out using NaCl as the pressure calibrants. The maximum pressure achieved was approximately 13 GPa. The neutron diffraction intensity from the newly generated anvil assemblies was 2.5-3.0 times greater than that using the standard toroidal anvil assemblies used previously.

  5. Moissanite anvil cell design for giga-pascal nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Meier, Thomas; Herzig, Tobias; Haase, Jürgen

    2014-04-01

    A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. 1H, 23Na, 27Al, 69Ga, and 71Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio.

  6. A Peltier cooling diamond anvil cell for low-temperature Raman spectroscopic measurements

    NASA Astrophysics Data System (ADS)

    Noguchi, Naoki; Okuchi, Takuo

    2016-12-01

    A new cooling system using Peltier modules is presented for a low-temperature diamond anvil cell instrument. This cooling system has many advantages: it is vibration-free, low-cost, and compact. It consists of double-stacked Peltier modules and heat sinks, where a cooled ethylene glycol-water mixture flows through a chiller. Current is applied to the Peltier modules by two programmable DC power supplies. Sample temperature can be controlled within the range 210-300 K with a precision of ±0.1 K via a Proportional-Integral-Differential (PID) control loop. A Raman spectroscopic study for the H2O ice VII-VIII transition is shown as an example of an application of the Peltier cooling diamond anvil cell system.

  7. Pulsed neutron powder diffraction at high pressure by a capacity-increased sapphire anvil cell

    NASA Astrophysics Data System (ADS)

    Okuchi, Takuo; Yoshida, Masashi; Ohno, Yoshiki; Tomioka, Naotaka; Purevjav, Narangoo; Osakabe, Toyotaka; Harjo, Stefanus; Abe, Jun; Aizawa, Kazuya; Sasaki, Shigeo

    2013-12-01

    A new design of opposed anvil cell for time-of-flight neutron powder diffraction was prepared for use at advanced pulsed sources. A couple of single-crystal sapphire sphere anvils and a gasket of fully hardened Ti-Zr null alloy were combined to compress 35 mm3 of sample volume to 1 GPa and 11 mm3 to 2 GPa of pressures, respectively. A very high-quality powder diffraction pattern was obtained at Japan Proton Accelerator Research Complex for a controversial high pressure phase of methane hydrate. The counting statistics, resolution, absolute accuracy and d-value range of the pattern were all improved to be best suitable for precise structure refinement. The sample is optically accessible to be measured by Raman and fluorescence spectroscopy during and after compression. The current cell will be an alternative choice to study hydrogenous materials of complex structures that are stable at the described pressure regime.

  8. Moissanite anvil cell design for Giga-Pascal nuclear magnetic resonance.

    PubMed

    Meier, Thomas; Herzig, Tobias; Haase, Jürgen

    2014-04-01

    A new design of a non-magnetic high-pressure anvil cell for nuclear magnetic resonance (NMR) experiments at Giga-Pascal pressures is presented, which uses a micro-coil inside the pressurized region for high-sensitivity NMR. The comparably small cell has a length of 22 mm and a diameter of 18 mm, so it can be used with most NMR magnets. The performance of the cell is demonstrated with external-force vs. internal-pressure experiments, and the cell is shown to perform well at pressures up to 23.5 GPa using 800 μm 6H-SiC large cone Boehler-type anvils. (1)H, (23)Na, (27)Al, (69)Ga, and (71)Ga NMR test measurements are presented, which show a resolution of better than 4.5 ppm, and an almost maximum possible signal-to-noise ratio.

  9. Efficient graphite ring heater suitable for diamond-anvil cells to 1300 K

    SciTech Connect

    Du Zhixue; Amulele, George; Lee, Kanani K. M.; Miyagi, Lowell

    2013-02-15

    In order to generate homogeneous high temperatures at high pressures, a ring-shaped graphite heater has been developed to resistively heat diamond-anvil cell (DAC) samples up to 1300 K. By putting the heater in direct contact with the diamond anvils, this graphite heater design features the following advantages: (1) efficient heating: sample can be heated to 1300 K while the DAC body temperature remains less than 800 K, eliminating the requirement of a special alloy for the DAC; (2) compact design: the sample can be analyzed with in situ measurements, e.g., x-ray, optical, and electrical probes are possible. In particular, the side access of the heater allows for radial x-ray diffraction (XRD) measurements in addition to traditional axial XRD.

  10. Cell assemblies for reproducible multi-anvil experiments (the COMPRES assemblies)

    SciTech Connect

    Leinenweber, Kurt D.; Tyburczy, James A.; Sharp, Thomas G.; Soignard, Emmanuel; Diedrich, Tamara; Petuskey, William B.; Wang, Yanbin; Mosenfelder, Jed L.

    2012-01-31

    The multi-anvil high-pressure technique is an important tool in high-pressure mineralogy and petrology, as well as in chemical synthesis, allowing the treatment of large (millimeter-size) samples of minerals, rocks, and other materials at pressures of a few GPa to over 25 GPa and simultaneous uniform temperatures up to 2500 C and higher. A series of cell assemblies specially designed and implemented for interlaboratory use are described here. In terms of the size of the pressure medium and the anvil truncation size, the five sizes of assemblies developed here are an 8/3, 10/5, 14/8, 18/12, and 25/15 assembly. As of this writing, these assemblies are in widespread use at many laboratories. The details of design, construction, and materials developed or used for the assemblies are presented here.

  11. Phase diagram determination up to 823K in minerals using Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Raju, S. V.; Knight, J.; Pawley, A. R.; Clark, S. M.

    2008-12-01

    : The ruby fluorescence technique is widely used for pressure measurement inside the diamond anvil cell. However, at higher temperatures estimation of pressure becomes complex due to the broadening of the fluorescence peaks. There are other fluorescence markers upon which temperature has a lower effect. For example Sm: SrB2O7. Here, we present a high pressure - high temperature calibration of Samarium doped SrB2O7. In order to minimize the error in determining the pressure, Strontium Borate along with Ruby were loaded in diamond anvil cell under hydrostatic conditions and fluorescence measurements were carried out upto temperatures of 823K under pressure. An equation routine is obtained to fit the peaks at various temperatures upto 823K under pressure. Using this data for pressure determination, phase diagram of Lawsonite was studied and the results are discussed.

  12. Note: Compact optical fiber coupler for diamond anvil high pressure cells

    NASA Astrophysics Data System (ADS)

    Pugh, E.

    2013-10-01

    A compact optical fiber coupler has been developed to allow transmission of light through an optical fiber to and from the high pressure region of a diamond anvil high pressure cell. Despite its small size the coupler has focusing adjustments and optics, which allows the light to be focused precisely on the sample within the pressure cell. The coupler is suitable for a wide range of optical measurements and particularly for high pressure measurements at low temperatures in cryostats with no optical windows. The use of the coupler to determine the pressure in a diamond anvil cell at 1.2 K using the ruby fluorescence spectra of ruby is demonstrated. The small size of the coupler and its construction out of nonmagnetic beryllium copper makes it suitable for use in high magnetic fields and for magnetization experiments.

  13. Integrated-fin gasket for palm cubic-anvil high pressure apparatus

    SciTech Connect

    Cheng, J.-G.; Matsubayashi, K.; Nagasaki, S.; Hisada, A.; Hirayama, T.; Uwatoko, Y.; Hedo, M.; Kagi, H.

    2014-09-15

    We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression.

  14. The determination of ionic transport properties at high pressures in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Wang, Qinglin; Liu, Cailong; Han, Yonghao; Gao, Chunxiao; Ma, Yanzhang

    2016-12-01

    A two-electrode configuration was adopted in an in situ impedance measurement system to determine the ionic conductivity at high pressures in a diamond anvil cell. In the experimental measurements, Mo thin-films were specifically coated on tops of the diamond anvils to serve as a pair of capacitance-like electrodes for impedance spectrum measurements. In the spectrum analysis, a Warburg impedance element was introduced into the equivalent circuit to reveal the ionic transport property among other physical properties of a material at high pressures. Using this method, we were able to determine the ionic transport character including the ionic conductivity and the diffusion coefficient of a sodium azide solid to 40 GPa.

  15. A Peltier cooling diamond anvil cell for low-temperature Raman spectroscopic measurements.

    PubMed

    Noguchi, Naoki; Okuchi, Takuo

    2016-12-01

    A new cooling system using Peltier modules is presented for a low-temperature diamond anvil cell instrument. This cooling system has many advantages: it is vibration-free, low-cost, and compact. It consists of double-stacked Peltier modules and heat sinks, where a cooled ethylene glycol-water mixture flows through a chiller. Current is applied to the Peltier modules by two programmable DC power supplies. Sample temperature can be controlled within the range 210-300 K with a precision of ±0.1 K via a Proportional-Integral-Differential (PID) control loop. A Raman spectroscopic study for the H2O ice VII-VIII transition is shown as an example of an application of the Peltier cooling diamond anvil cell system.

  16. Observations and modelling of microphysical variability, aggregation and sedimentation in tropical anvil cirrus outflow regions

    NASA Astrophysics Data System (ADS)

    Gallagher, M. W.; Connolly, P. J.; Crawford, I.; Heymsfield, A.; Bower, K. N.; Choularton, T. W.; Allen, G.; Flynn, M. J.; Vaughan, G.; Hacker, J.

    2012-07-01

    Aircraft measurements of the microphysics of a tropical convective anvil (at temperatures ~-60 °C) forming above the Hector storm, over the Tiwi Islands, Northern Australia, have been conducted with a view to determining ice crystal aggregation efficiencies from in situ measurements. The observed microphysics have been compared to an explicit bin-microphysical model of the anvil region, which includes crystal growth by vapour diffusion and aggregation and the process of differential sedimentation. It has been found in flights made using straight and level runs perpendicular to the storm that the number of ice crystals initially decreased with distance from the storm as aggregation took place resulting in larger crystals, followed by their loss from the cloud layer due to sedimentation. The net result was that the mass (i.e. Ice Water Content) in the anvil Ci cloud decreased, but also that the average particle size (weighted by number) remained relatively constant along the length of the anvil outflow. Comparisons with the explicit microphysics model showed that the changes in the shapes of the ice crystal spectra as a function of distance from the storm could be explained by the model if the aggregation efficiency was set to values of Eagg~0.5 and higher. This result is supported by recent literature on aggregation efficiencies for complex ice particles and suggests that either the mechanism of particle interlocking is important to the aggregation process, or that other effects are occuring, such as enhancement of ice-aggregation by high electric fields that arise as a consequence of charge separation within the storm. It is noteworthy that this value of the ice crystal aggregation efficiency is much larger than values used in cloud resolving models at these temperatures, which typically use E~0.0016. These results are important to understanding how cold clouds evolve in time and for the treatment of the evolution of tropical Ci in numerical models.

  17. Moissanite-anvil cells for the electrical transport measurements at low temperatures

    NASA Astrophysics Data System (ADS)

    Yomo, Shusuke; Tozer, Stanley W.

    2010-03-01

    We have successfully measured the Hall effect of a single crystal of a high temperature superconductor La2-xSrxCuO4 in moissanite-anvil high pressure cells. A pressure cell with new Zylon-gasket and wiring arrangement survived under pressure up to at least 5 GPa. Pressure which was clamped at room temperature increased with lowering the temperature down to below 60 K by a factor of 1.3-1.4.

  18. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    SciTech Connect

    Yan, Zhaoli Tian, Hao; Cheng, Xiaobin; Yang, Jun; Chen, Bin

    2015-12-15

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10{sup −4} during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  19. Cryogenic loading of argon pressure medium in diamond anvil high pressure cells with in situ pressure determination

    NASA Astrophysics Data System (ADS)

    Pugh, E.

    2017-06-01

    A versatile system for cryogenic loading of argon pressure medium into the sample space of a diamond anvil cell has been developed. The system has been designed such that, with suitable adaptors, a wide range of diamond anvil cell designs can be pressurized. The pressure in the cell can be monitored during pressurization using the ruby fluorescence method via optical fiber access into the loading chamber. This enables the precise and accurate setting of the loading pressure in the cell.

  20. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    NASA Astrophysics Data System (ADS)

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10-4 during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  1. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus.

    PubMed

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10(-4) during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  2. Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells

    SciTech Connect

    Kupenko, I. Strohm, C.; McCammon, C.; Cerantola, V.; Petitgirard, S.; Dubrovinsky, L.; Glazyrin, K.; Vasiukov, D.; Aprilis, G.; Chumakov, A. I.; Rüffer, R.

    2015-11-15

    Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamond anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe{sub 3}C using synchrotron Mössbauer source spectroscopy, FeCO{sub 3} using nuclear inelastic scattering, and Fe{sub 2}O{sub 3} using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses.

  3. Opposed-anvil-type high-pressure and high-temperature apparatus using sintered diamond

    NASA Astrophysics Data System (ADS)

    Gotou, Hirotada; Yagi, Takehiko; Frost, Daniel J.; Rubie, David C.

    2006-03-01

    An opposed-anvil-type high-pressure and high-temperature apparatus is developed, adopting sintered diamond as the anvil material. Pressures and temperatures up to about 30GPa and 1700K can be achieved routinely without difficulty. The use of a metal gasket dramatically reduces the occurrence of blowouts and results in very stable pressure generation. By improving the preparation methods and materials used for the small components of the sample assembly, experiments can be performed much more easily than with previous versions of the apparatus. Pressures and temperatures were measured by in situ x-ray diffraction using two different pressure markers. Temperatures of the sample were also estimated from the resistance change of the heater. Estimated pressure and temperature conditions were checked by the phase transformation of Al-bearing MgSiO3 and were consistent with the stability field of the perovskite phase as previously reported. Compared to the laser-heated diamond anvil cell, this apparatus has the advantage of uniform temperature and a much larger sample volume. As a result, the new apparatus has major advantages for studying multicomponent systems and the partitioning of the elements.

  4. Limb Retrievals of the martian atmosphere: Mapping with optical observations from MGS/TES and MRO/MCS.

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Clancy, R. T.; Smith, M. J.; Bandfield, J.; Pankine, A.

    2015-12-01

    Limb observations in the optical regime represent a vastly underutilized resource for studies of the Martian atmosphere. In an effort to rectify this situation, our presentation will attempt to provide the framework for an interested individual to identify a data set of potential interest, access said data and associated metadata products, and obtain a radiative transfer tool that would enable the appropriate analyses. More specifically, we will highlight the coverage and capabilities of the optical limb observations from the Thermal Emission Spectrometer (TES) and the Mars Climate Sounder (MCS). We will also present several radiative transfer algorithms that may be employed to interpret the various data sets. Finally, we will highlight several applications of the limb observations including mapping of dust vertical profile characteristics, detached layers, and particle size retrievals. This last example employs the simultaneous use of infrared limb observations from both the TES and MCS data. This work is (and has been) supported by NASA with a Mars Data Analysis Program award (grant NNX10AO23G).

  5. Geophysics Under Pressure: Large-Volume Presses Versus the Diamond-Anvil Cell

    NASA Astrophysics Data System (ADS)

    Hazen, R. M.

    2002-05-01

    Prior to 1970, the legacy of Harvard physicist Percy Bridgman dominated high-pressure geophysics. Massive presses with large-volume devices, including piston-cylinder, opposed-anvil, and multi-anvil configurations, were widely used in both science and industry to achieve a range of crustal and upper mantle temperatures and pressures. George Kennedy of UCLA was a particularly influential advocate of large-volume apparatus for geophysical research prior to his death in 1980. The high-pressure scene began to change in 1959 with the invention of the diamond-anvil cell, which was designed simultaneously and independently by John Jamieson at the University of Chicago and Alvin Van Valkenburg at the National Bureau of Standards in Washington, DC. The compact, inexpensive diamond cell achieved record static pressures and had the advantage of optical access to the high-pressure environment. Nevertheless, members of the geophysical community, who favored the substantial sample volumes, geothermally relevant temperature range, and satisfying bulk of large-volume presses, initially viewed the diamond cell with indifference or even contempt. Several factors led to a gradual shift in emphasis from large-volume presses to diamond-anvil cells in geophysical research during the 1960s and 1970s. These factors include (1) their relatively low cost at time of fiscal restraint, (2) Alvin Van Valkenburg's new position as a Program Director at the National Science Foundation in 1964 (when George Kennedy's proposal for a Nation High-Pressure Laboratory was rejected), (3) the development of lasers and micro-analytical spectroscopic techniques suitable for analyzing samples in a diamond cell, and (4) the attainment of record pressures (e.g., 100 GPa in 1975 by Mao and Bell at the Geophysical Laboratory). Today, a more balanced collaborative approach has been adopted by the geophysics and mineral physics community. Many high-pressure laboratories operate a new generation of less expensive

  6. Upper tropospheric cloud systems derived from IR sounders: properties of cirrus anvils in the tropics

    NASA Astrophysics Data System (ADS)

    Protopapadaki, Sofia E.; Stubenrauch, Claudia J.; Feofilov, Artem G.

    2017-03-01

    Representing about 30 % of the Earth's total cloud cover, upper tropospheric clouds play a crucial role in the climate system by modulating the Earth's energy budget and heat transport. When originating from convection, they often form organized systems. The high spectral resolution of the Atmospheric Infrared Sounder (AIRS) allows reliable cirrus identification, both from day and nighttime observations. Tropical upper tropospheric cloud systems have been analyzed by using a spatial composite technique on the retrieved cloud pressure of AIRS data. Cloud emissivity is used to distinguish convective core, cirrus and thin cirrus anvil within these systems. A comparison with simultaneous precipitation data from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) shows that, for tropical upper tropospheric clouds, a cloud emissivity close to 1 is strongly linked to a high rain rate, leading to a proxy to identify convective cores. Combining AIRS cloud data with this cloud system approach, using physical variables, provides a new opportunity to relate the properties of the anvils, including also the thinner cirrus, to the convective cores. It also distinguishes convective cloud systems from isolated cirrus systems. Deep convective cloud systems, covering 15 % of the tropics, are further distinguished into single-core and multi-core systems. Though AIRS samples the tropics only twice per day, the evolution of longer-living convective systems can be still statistically captured, and we were able to select relatively mature single-core convective systems by using the fraction of convective core area within the cloud systems as a proxy for maturity. For these systems, we have demonstrated that the physical properties of the anvils are related to convective depth, indicated by the minimum retrieved cloud temperature within the convective core. Our analyses show that the size of the systems does in general increase with convective depth, though for

  7. Spin transition of Fe2+ in (Fe0.83Fe0.17)O in the multi anvil apparatus equipped with sintered diamond anvils

    NASA Astrophysics Data System (ADS)

    Ito, E.; Yoshino, T.; Yamazaki, D.; Shatsky, A.; Guo, X.; Shan, S.; Katsura, T.; Yoneda, A.; Higo, Y.; Funakoshi, K.

    2010-12-01

    We have improved performance of the Kawai-type multi anvil apparatus by adopting sintered diamond anvils with an edge length of 14 mm and a truncated corner of 1.0 mm. Most experiments have been carried out at synchrotron facility SPring-8 in Japan. The Kawai-cell (an assemblage of eight cubic anvils and an octahedral specimen) has been squeezed in the DIA-type apparatus installed on the beam line BL04B1. Sample mixed with pressure standard such as Au has been examined by in situ X-ray diffraction method, and the experimental pressure is simultaneously determined from measured volume of the standard material via its EoS. Recently maximum attainable pressure exceeded 95 GPa [Ito et al., 2010]. Based on the experimental innovation, we have investigated the high spin (HS) to low spin (LS) transition of Fe2+ in (Mg1-xFex) ferropericlase (Fp) under lower mantle conditions. Since the effective ionic radius of Fe2+ in LS state is substantially smaller than that in HS state, the spin transition brings about a definite volume contraction together with an increase in bulk modulus. The progressive transition in Fp solid solution with pressure causes a regime of mixed spin state at pressures between those of HS and LS states. The feature should be realized along a P-V compression curve [e.g., Lin and Tsuchiya, 2008]. We have acquired the P-V data of (Mg0.83Fe0.17)O Fp up to 90 GPa and at 300 and 700 K with errors less than ±0.006 Å3 in volume and ±0.4 GPa in pressure. Pressure determination is based on the Anderson et al’s [1989] Au scale. From detailed analysis of the data by fitting the 3rd order Birch-Murnaghan EoS, it has been concluded that the spin transition proceeds over pressure ranges from 50 to 70 GPa at 300 K and from 60 to 85 GPa.

  8. Wave-Modulated CO2 Condensation in Mars' Polar Atmosphere From MGS/TES & MOLA and MRO/MCS.

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.

    2016-12-01

    In Mars' polar night, atmospheric temperatures fall low enough to cause CO2 condensation. This has been empirically demonstrated by Mars Global Surveyor's (MGS) Mars Orbiter Laser Altimeter (MOLA), which identified reflections from above the surface, and MGS Radio Science (RS) and Thermal Emission Spectrometer (TES) and Mars Reconnaissance Orbiter's (MRO) Mars Climate Sounder (MCS), all of which showed polar night temperature profiles that were super-saturated. Detailed analysis of TES temperature profiles as well as numerical modeling both suggest that the stationary and traveling waves on the polar vortices are strong enough to significantly modulate the CO2 cloud condensation. However the extent to which this is actually occurring has not been quantified. The polar night CO2 condensation represents a significant amount of energy deposition, even if it were uniformly distributed. If instead it is concentrated in the cold sectors of the various waves, this can be a tremendous perturbation not only to the wave amplitudes (clipping them from going much below the CO2 condensation temperature), but also impacting their ability to transport heat and momentum poleward and upward, and thus it may also impact the maintenance and shape of the polar vortex itself. Mars' polar vortices remain barotropically unstable throughout the winter in spite of large amplitude waves in their vicinity. We have identified when and where the various waves (with their specific amplitudes and phases) in the vicinity of the polar vortex should modulate the CO2 condensation (see Figure of a meridional cross-section showing where no clouds are expected (blue), clouds should be ubiquitous (green) and waves should be required to form clouds (red)). We have also correlated this with the distribution of the actual observed cloud identifications from MGS MOLA and MRO MCS. We find only poor correlations between the MGS/TES identified wave modulated condensation predictions and actual simultaneous

  9. Pulsatile-flow mechanical circulatory support (MCS) as a bridge to transplantation or recovery. Single-centre experience with the POLCAS system in 2014.

    PubMed

    Kuśmierczyk, Mariusz; Kuć, Mateusz; Szymański, Jarosław; Juraszek, Andrzej; Kołsut, Piotr; Kuśmierski, Krzysztof; Zieliński, Tomasz; Sobieszczańska-Małek, Małgorzata; Sitkowska-Rysiak, Ewa

    2015-09-01

    Mechanical circulatory support (MCS) is a recognised method of treatment for patients with end-stage chronic or acute heart failure. The POLCAS pulsatile-flow system has been used in our institution for 15 years. Currently, it is being widely replaced by continuous-flow mechanical circulatory support equipment of the second and third generations (HeartMateII, HeartWare). The MCS presented in this study is associated with a significant risk of complications and its use is increasingly considered controversial. The aim of the study was an evaluation of the results of treatment utilising the POLCAS MCS system at our institution in 2014. The POLCAS system was implanted in 12 patients aged 16-63 years (42 ± 17 years) during a period of 12 months (from January to December, 2014). Full-blown cardiogenic shock was observed in all patients before MCS implantation. Four of the analysed patients (33%) required prior circulatory support with other devices: IABP (n = 2) or ECMO (n = 2). Episodes of cardiac arrest were reported in three patients; three other patients experienced serious arrhythmias, which accelerated the decision to implant MCS. The presented data was retrospectively obtained from the CliniNET system of the Institute of Cardiology. OpenOffice Calc spreadsheet was used for data analysis. Average MCS time was 41 days ± 25 (from 15 to 91 days). Survival until transplantation or explantation was 91.67%. The most frequent complications following the therapy were: cardiac tamponade or bleeding requiring an intervention - 25% (n = 3), renal failure requiring dialysis - 25% (n = 3), ischaemic stroke associated with the MCS - 16.6% (n = 2), bacteraemia - 16.6% (n = 2), and wound infection - 8% (n = 1). No malfunctions of the MCS system were reported. Early survival in patients who completed the MCS therapy, defined as discharge, amounted to 63.6% (n = 7). The POLCAS heart assist system is an effective method of treatment as a bridge to transplantation or recovery in

  10. Tectonic Inversion of the Algerian Continental Margin off Great Kabylia (North Algeria) - Insights from new MCS data (SPIRAL cruise)

    NASA Astrophysics Data System (ADS)

    Aidi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Karim; Ribodetti, Alessandra; Bracene, Rabah; Schenini, Laure; Djellit, Hamou; Sage, Françoise; Déverchère, Jacques; Medaouri, Mourad; Klingelhoefer, Frauke; Abtout, Abdeslam; Charvis, Philippe; Bounif, Abdallah

    2014-05-01

    Sub-marine active faulting threatens the coastline of Algeria, as shown by the major Mw 6.9 May 21, 2003 earthquake that occurred in Great Kabylia close to Boumerdes. We present here the structures associated to the Plio-Quaternary (P-Q) tectonic inversion of the central part of the Algerian margin offshore Great Kabylia using new deep multichannel seismic (MCS) lines. Five MCS lines were acquired in the study area during the Algerian-French SPIRAL cruise (September 2009, R/V Atalante). Four lines were acquired using a 3040 cu. in. air-gun array and a 4.5 km 360 channel digital streamer and a 8350 cu. in. source favoring deep penetration was used for one coincident WAS profile and the fifth MCS line. All profiles are pre-stack time migrated and additional pre-stack depth migration was performed in key areas. The MCS lines crosscut the margin from the upper slope to the deep Algero-Provençal Basin either in a N-S direction sub-perpendicular to the structural trend of the margin, or in a NW-SE direction parallel to the actual convergence between Africa and Eurasia plates. Tectonic inversion is expressed on all profiles at the deep margin. The eastern line displays a flat-ramp compressive system in the deep sedimentary series, which emerges at the foot of the continental slope and marks the seaward limit of a P-Q basin perched at mid-slope. The south-dipping ramps are neo-formed structures, whereas the flats use inherited lithologic discontinuities (base of the Messinian evaporitic series, top of the acoustic basement). Westward in the Boumerdes area, the compressive deformation is expressed deeper in the acoustic basement where a southward dipping reflector is interpreted as a blind thrust on top of which all the sedimentary series (Miocene to P-Q) are bent in an antiform that uplifts the base of the Messinian series. A second antiform prolongates this uplift 20 km northward although no clear reverse structure is imaged underneath. These antiforms delimit two

  11. The role of in process qualification in quality improvement of the haemonetics MCS plus leucodepleted platelet concentrate.

    PubMed

    Seghatchian, J; Beard, M; Krailadsiri, P

    2000-06-01

    With the implementation of universal leucodepletion in UK all leucodepletion processes have gone through a standard process qualification and quality improvement. The Haemonetics MCS system is a well established automated platelet collection system for the production of double dose leucoreduced platelet concentrate (WBC approximately 70x10(6)/dose). Recently an automated post collection filtration harness system has been introduced (MCS plus LDP) in which platelets are filtered, using an in-line PALL polyester filter (LRFH6 PALL) to reduce the WBC level to below 5x10(6) WBC/dose. This system passed our Phase I evaluation process based on 20-40 runs. However, some changes in the final volume of the products were needed to conform to national guidelines. Large scale trials using the new volume adjusted protocol revealed occasional failure in the leucocyte content. Therefore, 100% testing had to be implemented on all products. A national evaluation was carried out to determine whether changing the filter to a more efficacious one, the LRFXL (PALL) or slowing the filtration flow rate can influence the overall outcome. To reduce donor variability, known donor population were used with identical apheresis conditions. A more consistent and systematic drop in leucocyte content was observed by reducing the flow rate whereas a similar failure (i.e. 1-3%) rate was found both in controls and LRFXL when using the standard head pressure, which is recommended by the manufacturer. A similar failure rate was found using three different low leucocyte counting technologies (Nageotte, flow cytometry and Imagn 2000). It is recommended that a process qualification/validation program should be implemented when even a small modification in the collection system is introduced.

  12. Tropical anvil characteristics and water vapor of the tropical tropopause layer: Impact of heterogeneous and homogeneous freezing parameterizations

    SciTech Connect

    Fan, Jiwen; Comstock, Jennifer M.; Ovchinnikov, Mikhail; McFarlane, Sally A.; McFarquhar, Greg; Allen, Grant

    2010-06-16

    Abstract Two isolated deep convective clouds (DCCs) that developed in clean-humid and polluted-dry air masses, observed during the TWP-ICE and ACTIVE campaigns, are simulated using a 3-dimensional cloud-resolving model with size-resolved aerosol and cloud microphysics. We examine the impacts of different homogeneous and immersion freezing parameterizations on the anvil characteristics and the water vapor content (WVC) in the Tropical Tropopause Layer (TTL) for the two DCCs that developed in contrasting environments. The modeled cloud properties such as liquid/ice water path and precipitation generally agree with the available radar and satellite retrievals and in situ aircraft measurements. We find that anvil size and anvil microphysical properties such as ice number concentration and ice effective radius (rei) are much more sensitive to the homogeneous freezing parameterization (HomFP) under the polluted-dry condition, while the strength of anvil convection is more sensitive to HomFP under the clean-humid condition. Specifically, the cloud anvil with the Koop et al. (2000) (KOOP) relative humidity dependent scheme has up to 2 and 4 times lower ice number than those with other schemes (temperature dependent) for the clean humid and polluted-dry cases, respectively. Consequently, the rei is increased in both cases, with a larger increase in the polluted-dry case. As a result, extinction coefficient of cloud anvils is reduced by over 25% for the polluted-dry case. Anvil size and evolution are also much affected by HomFPs in the polluted-dry case. Higher immersion-freezing rates leads to a stronger convective cloud, with higher precipitation and ice water path under both humid and dry conditions. As a result, homogeneous freezing rates are enhanced by over 20%. Also, the higher immersion-freezing rate results in stronger convection in cloud anvils, much larger anvil size (up to 3 times) and longer lifetime. The moistening effect of deep convection on the WVC in the

  13. Preliminary Analysis and Simulations of July 23rd Extended Anvil Case

    NASA Technical Reports Server (NTRS)

    Lin, R.-F.; Demoz, B.; McGill, M.; Heymsfield, G.; Sassen, K.; Bui, P.; Heymsfield, A.; Halverson, J.; Rickenbach, T.; Poellot, M.; Lare, A.

    2003-01-01

    A key focus of CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and cirrus Layers - Florida Area Cirrus Experiment) was the generation and subsequent evolution of cirrus outflow from deep convective cloud systems. A preliminary integrated look at the observations of an extended cirrus anvil cloud system observed on 23 July 2002 will be presented, including lidar and millimeter radar observations from NASA's ER-2 and in- situ observations from NASA's WB-57 and University of North Dakota Citation. The observations will be compared to preliminary results of simulations using 1-D and 2-D high-resolution (100 meter) cloud resolving models. The CRMs explicitly account for cirrus microphysical development by resolving the evolving ice crystal size distribution (bin model) in time and space. Both homogeneous and heterogeneous nucleation are allowed in the model. The CRM simulations are driven using the output of regional simulations using MM5 that produces deep convection similar to what was observed. The MM5 model employs a 2 km inner grid (32 layers) over a 360 km domain, nested within a 6 km grid over a 600 km domain. Initial and boundary conditions for the 36- hour MM5 simulation are taken from NCEP Eta model analysis at 32 km resolution. Key issues to be explored are the settling of the observed anvil versus the model simulations, and comparisons of dynamical properties, such as vertical motions, occurring in the observations and models. The former provides an integrated measure of the validity of the model microphysics (fallspeed) while the latter is the key factor in forcing continued ice generation.

  14. Aerosol-Induced Changes of Convective Cloud Anvils Produce Strong Climate Warming

    NASA Technical Reports Server (NTRS)

    Koren, I.; Remer, L. A.; Altaratz, O.; Martins, J. V.; Davidi, A.

    2010-01-01

    The effect of aerosol on clouds poses one of the largest uncertainties in estimating the anthropogenic contribution to climate change. Small human-induced perturbations to cloud characteristics via aerosol pathways can create a change in the top-of-atmosphere radiative forcing of hundreds of Wm(exp-2) . Here we focus on links between aerosol and deep convective clouds of the Atlantic and Pacific Intertropical Convergence Zones, noting that the aerosol environment in each region is entirely different. The tops of these vertically developed clouds consisting of mostly ice can reach high levels of the atmosphere, overshooting the lower stratosphere and reaching altitudes greater than 16 km. We show a link between aerosol, clouds and the free atmosphere wind profile that can change the magnitude and sign of the overall climate radiative forcing. We find that increased aerosol loading is associated with taller cloud towers and anvils. The taller clouds reach levels of enhanced wind speeds that act to spread and thin the anvi1 clouds, increasing areal coverage and decreasing cloud optical depth. The radiative effect of this transition is to create a positive radiative forcing (warming) at top-of-atmosphere. Furthermore we introduce the cloud optical depth (r), cloud height (Z) forcing space and show that underestimation of radiative forcing is likely to occur in cases of non homogenous clouds. Specifically, the mean radiative forcing of towers and anvils in the same scene can be several times greater than simply calculating the forcing from the mean cloud optical depth in the scene. Limitations of the method are discussed, alternative sources of aerosol loading are tested and meteorological variance is restricted, but the trend of taller clouds; increased and thinner anvils associated with increased aerosol loading remains robust through all the different tests and perturbations.

  15. CRYSTAL-FACE Analysis and Simulations of the July 23rd Extended Anvil Case

    NASA Technical Reports Server (NTRS)

    Starr, David

    2003-01-01

    A key focus of CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and cirrus Layers - Florida Area Cirrus Experiment) was the generation and subsequent evolution of cirrus outflow from deep convective cloud systems. Present theoretical background and motivations will be discussed. An integrated look at the observations of an extended cirrus anvil cloud system observed on 23 July 2002 will be presented, including lidar and millimeter radar observation; from NASA s ER-2 and in-situ observations from NASA s WB-57 and University of North Dakota Citation. The observations will be compared to results of simulations using 1-D and 2-D high-resolution (100 meter) cloud resolving models. The CRMs explicitly account for cirrus microphysical development by resolving the evolving ice crystal size distribution (bin model) in time and space. Both homogeneous and heterogeneous nucleation are allowed in the model. The CRM simulations are driven using the output of regional simulations using MM5 that produces deep convection similar to what was observed. The MM5 model employs a 2 km inner grid (32 layers) over a 360 km domain, nested within a 6-km grid over a 600-km domain. Initial and boundary conditions for the 36-hour MM5 simulation are taken from NCEP Eta model analysis at 32 km resolution. Key issues to be explored are the settling of the observed anvil versus the model simulations, and comparisons of dynamical properties, such as vertical motions, occurring in the observations and models. The former provides an integrated measure of the validity of the model microphysics (fallspeed) while the latter is the key factor in forcing continued ice generation.

  16. CRYSTAL-FACE Analysis and Simulations of the July 23rd Extended Anvil Case

    NASA Technical Reports Server (NTRS)

    Starr, David

    2003-01-01

    A key focus of CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and cirrus Layers - Florida Area Cirrus Experiment) was the generation and subsequent evolution of cirrus outflow from deep convective cloud systems. Present theoretical background and motivations will be discussed. An integrated look at the observations of an extended cirrus anvil cloud system observed on 23 July 2002 will be presented, including lidar and millimeter radar observation; from NASA s ER-2 and in-situ observations from NASA s WB-57 and University of North Dakota Citation. The observations will be compared to results of simulations using 1-D and 2-D high-resolution (100 meter) cloud resolving models. The CRMs explicitly account for cirrus microphysical development by resolving the evolving ice crystal size distribution (bin model) in time and space. Both homogeneous and heterogeneous nucleation are allowed in the model. The CRM simulations are driven using the output of regional simulations using MM5 that produces deep convection similar to what was observed. The MM5 model employs a 2 km inner grid (32 layers) over a 360 km domain, nested within a 6-km grid over a 600-km domain. Initial and boundary conditions for the 36-hour MM5 simulation are taken from NCEP Eta model analysis at 32 km resolution. Key issues to be explored are the settling of the observed anvil versus the model simulations, and comparisons of dynamical properties, such as vertical motions, occurring in the observations and models. The former provides an integrated measure of the validity of the model microphysics (fallspeed) while the latter is the key factor in forcing continued ice generation.

  17. Modulation calorimetry in diamond anvil cells. II. Joule-heating design and prototypes

    NASA Astrophysics Data System (ADS)

    Geballe, Zachary M.; Struzhkin, Viktor V.; Townley, Andrew; Jeanloz, Raymond

    2017-04-01

    Part I shows that quantitative measurements of heat capacity are theoretically possible inside diamond anvil cells via high-frequency Joule heating (100 kHz-10 MHz), opening up the possibility of new methods to detect and characterize transformations at high-pressure such as the glass transitions, melting, magnetic orderings, and the onset of superconductivity. Here, we test the possibility outlined in Part I, using prototypes and detailed numerical models. First, a coupled electrical-thermal numerical model shows that specific heat of metals inside diamond cells can be measured directly using ˜1 MHz frequency, with <10 % accuracy. Second, we test physical models of high-pressure experiments, i.e., diamond-cell mock-ups. Metal foils of 2-6 μm-thickness are clamped between glass insulation inside diamond anvil cells. Fitting data from 10 Hz to ˜30 kHz, we infer the specific heat capacities of Fe, Pt, and Ni with ±20%-30% accuracy. The electrical test equipment generates -80 dBc spurious harmonics, which overwhelm the thermally induced harmonics at higher frequencies, disallowing the high precision expected from numerical models. An alternative Joule-heating calorimetry experiment, on the other hand, does allow absolute measurements with <10 % accuracy, despite the -80 dBc spurious harmonics: the measurement of thermal effusivity, √{ρc k } (ρ, c, and k being density, specific heat, and thermal conductivity), of the insulation surrounding a thin-film heater. Using a ˜50 nm-thick Pt heater surrounded by glass and 10 Hz-300 kHz frequency, we measure thermal effusivity with ±6 % accuracy inside the sample chamber of a diamond anvil cell.

  18. Special dyeing, histochemistry, immunohistochemistry and ultrastructure: A study of mast cells/eosinophilic granules cells (MCs/EGC) from Centropomus parallelus intestine.

    PubMed

    da Silva, Wémeson F; Simões, Manuel J; Gutierre, Robson C; Egami, Mizue I; Santos, Antenor A; Antoniazzi, Marta M; Sasso, Gisela R; Ranzani-Paiva, Maria José T

    2017-01-01

    Intestine mast cells/eosinophilic granule cells (MCs/EGC) of the marine species Centropomus parallelus (fat snook) were first studied using light and electron microscopy techniques. Mast cells are cells from the connective tissue found in almost all organs and tissues of vertebrates. In fish, they appear in greater numbers in parts of their bodies that are exposed to their environment, such as skin, gills and intestine. The granules in fat snook's mast cell contain a variety of substances, such as histamine, heparin, chondroitin sulfate, serotonin, proteases and cytokines. The present study of intestine MCs/EGC was carried out in 20 specimens of fat snook. Samples of tissue were fixed in Bouin solution and in buffered formalin. Ferric hematoxylin - Congo red, pH6 acridine orange, pH2.5 and pH0,5 Alcian Blue (AB), toluidine blue, PAS, AB + PAS and immunohistochemistry protocols were used. In the mucosa and submucosa layers, MCs/EGCs granules with basic contents were evidenced by Congo red staining, and with acid contents granules were identified through pH 2.5 and 0,5 AB, and acridine orange. Basic and acid contents were simultaneously evidenced using ferric hematoxylin - Congo red stain. Metachromasia was observed in both mucosal and submucosal mast cells. Neutral glycoproteins were evidenced by using PAS protocol, glycosaminoglycan through AB and both simultaneously through AB + PAS. In immunohistochemistry assays, MCs/EGC were positive for tryptase, chymase and serotonin. As in mammals, the study of samples fixed in modified Karnovsky for transmission electron microscopy evidenced that most of the MCs granules were spherical and showed varying electron density, as described in previous reports on other teleost fish species. The metachromasia observed and the identification of tryptase, chymase and serotonin suggest a great similarity between fat snook's MCs/EGC and those described in the mucosa of mammals.

  19. Predicting an SF-6D Preference-Based Score Using MCS and PCS Scores from the SF-12 or SF-36

    PubMed Central

    Hanmer, Janel

    2014-01-01

    Background The SF-6D preference-based scoring system was developed several years after the SF-12 and SF-36 instruments. A method to predict SF-6D scores from information in previous reports would facilitate backwards comparisons and the use of these reports in cost-effectiveness analyses. Methods This report uses data from the 2001–2003 Medical Expenditures Panel Survey (MEPS), the Beaver Dam Health Outcomes Survey, and the National Health Measurement Study. SF-6D scores were modeled using age, sex, mental component summary (MCS) score, and physical component summary (PCS) score from the 2002 MEPS. The resulting SF-6D prediction equation was tested with the other datasets for groups of different sizes and groups stratified by age, MCS score, PCS score, sum of MCS and PCS scores, and SF-6D score. Results The equation can be used to predict an average SF-6D score using average age, proportion female, average MCS score, and average PCS score. Mean differences between actual and predicted average SF-6D scores in out-of-sample tests was −0.001 (SF-12 version 1), −0.013 (SF-12 version 2), −0.007 (SF-36 version 1), and −0.010 (SF-36 version 2). Ninety-five percent credible intervals around these point estimates range from ±0.045 for groups with 10 subjects to ±0.008 for groups with more than 300 subjects. These results were consistent for a wide range of ages, MCS scores, PCS scores, sum of MCS and PCS scores, and SF-6D scores. SF-6D scores from the SF-36 and SF-12 from the same data set were found to be substantially different. Conclusions Simple equation predicts an average SF-6D preference-based score from widely published information. PMID:19490549

  20. Plasma etching of cavities into diamond anvils for experiments at high pressures and high temperatures

    SciTech Connect

    Weir, S.T.; Cynn, H.; Falabella, S.; Evans, W.J.; Aracne-Ruddle, C.; Farber, D.; Vohra, Y.K.

    2012-10-23

    We describe a method for precisely etching small cavities into the culets of diamond anvils for the purpose of providing thermal insulation for samples in experiments at high pressures and high temperatures. The cavities were fabricated using highly directional oxygen plasma to reactively etch into the diamond surface. The lateral extent of the etch was precisely controlled to micron accuracy by etching the diamond through a lithographically fabricated tungsten mask. The performance of the etched cavities in high-temperature experiments in which the samples were either laser heated or electrically heated is discussed.

  1. An electrical microheater technique for high-pressure and high-temperature diamond anvil cell experiments.

    PubMed

    Weir, S T; Jackson, D D; Falabella, S; Samudrala, G; Vohra, Y K

    2009-01-01

    Small electrical heating elements have been lithographically fabricated onto the culets of "designer" diamond anvils for the purpose of performing high-pressure and high-temperature experiments on metals. The thin-film geometry of the heating elements makes them very resistant to plastic deformation during high-pressure loading, and their small cross-sectional area enables them to be electrically heated to very high temperatures with relatively modest currents (approximately = 1 A). The technique also offers excellent control and temporal stability of the sample temperature. Test experiments on gold samples have been performed for pressures up to 21 GPa and temperatures of nearly 2000 K.

  2. New Approach to High-Pressure Nuclear Magnetic Resonance with Anvil Cells

    NASA Astrophysics Data System (ADS)

    Meissner, T.; Goh, S. K.; Haase, J.; Meier, B.; Rybicki, D.; Alireza, P. L.

    2010-04-01

    A novel approach that uses radio-frequency microcoils in the high-pressure region of anvil cells with Nuclear Magnetic Resonance (NMR) experiments is described. High-sensitivity Al NMR data at 70 kbar for Al metal are presented for the first time. An expected decrease in the Al Knight shift at 70 kbar is observed, as well as an unexpected change in the local charge symmetry at the Al nucleus. The latter is not predicted by chemical structure analysis under high pressure.

  3. Testing of a Helmholtz Microcoil in a Diamond Anvil Cell NMR

    NASA Astrophysics Data System (ADS)

    Lin, Ching; Weir, Sam; Evans, William; Chantel, A.; Vohra, Y.; Samudrala, G.; Crocker, J.; Shockley, A.; Curro, Nicholas

    2012-02-01

    A new designed, multi-turn tungsten Helmholtz micro-coil has been constructed and tested on the solid-state bulk NMR experiment. A Helmholtz micro-coil with diameter 950 μm is embedded on diamond culet and produces a nearly uniform AC magnetic field inside a sample space. A Fluorine polycrystal will be used to test our Helmholtz micro-coil, and the measured NMR data will be compared with the ones produced by other type of diamond anvil cell coils. The Helmholtz micro-coil will be used for high pressure NMR and future investigation of magnetic properties of heavy fermion superconductors.

  4. Finite element analysis of resistivity measurement with van der Pauw method in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Huang, Xiaowei; Gao, Chunxiao; Han, Yonghao; Li, Ming; He, Chunyuan; Hao, Aimin; Zhang, Dongmei; Yu, Cuiling; Zou, Guangtian; Ma, Yanzhang

    2007-06-01

    Using finite element analysis, the authors studied the steady current field distribution under the configuration of van der Pauw method [L. J. van der Pauw, Philips Tech. Rev. 20, 220 (1958)] for resistivity measurement in a diamond anvil cell. Based on the theoretical analysis, the authors obtained the theoretical accuracy curve of the van der Pauw method. This method provides accurate determination of sample resistivity when the ratio of sample thickness to its diameter is less than 0.45. They found that the contact area between electrode and sample is a key factor in the resistivity measurement accuracy and its size is dependent on the sample diameter for a given measurement accuracy.

  5. Remote measurements of the structure of midwest thunderstorm tops and anvils from high altitude aircraft

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Fulton, Richard

    1990-01-01

    Results are presented from observations by a visible and IR scanning radiometer, a scanning passive microwave radiometer, and a nadir-viewing cloud lidar system (CLS), carried out from ER-2 overflights for two midwest severe weather events both of which presented following phenomena: (1) a group of severe thunderstorms which later transformed into a linear mesoscale convective system, and (2) a severe thunderstorm which produced large hail. Most of the aircraft in situ and remote measurements pointed to a deep subsidence region and gravity waves downstream of the overshooting cloud tops. The observations do not support a radiative explanation for the warm areas in the anvil.

  6. Note: High-pressure in situ x-ray laminography using diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Nomura, Ryuichi; Uesugi, Kentaro

    2016-04-01

    A high-pressure in situ X-ray laminography technique was developed using a newly designed, laterally open diamond anvil cell. A low X-ray beam of 8 keV energy was used, aiming at future application to dual energy X-ray chemical imaging techniques. The effects of the inclination angle and the imaging angle range were evaluated at ambient pressure using the apparatus. Sectional images of ruby ball samples were successfully reconstructed at high pressures, up to approximately 50 GPa. The high-pressure in situ X-ray laminography technique is expected to provide new insights into the deep Earth sciences.

  7. Cryogenic implementation of charging diamond anvil cells with H2 and D2.

    PubMed

    Chi, Zhenhua; Nguyen, Huyen; Matsuoka, Takahiro; Kagayama, Tomoko; Hirao, Naohisa; Ohishi, Yasuo; Shimizu, Katsuya

    2011-10-01

    A cryogenic loading system for introducing H(2) and D(2) into the diamond anvil cell has been designed and constructed. The integration of pressure loading mechanism, ruby fluorescence spectrometer, and microscope camera allows for in situ tuning and calibrating the pressure. The performance of the system has been demonstrated by successful synthesis of hydride and deuteride of transition metal and rare earth metal. Our cryogenic methodology features facile start-over of loading and in situ electrical resistance measurement of as-synthesized sample.

  8. Note: High-pressure in situ x-ray laminography using diamond anvil cell

    SciTech Connect

    Nomura, Ryuichi; Uesugi, Kentaro

    2016-04-15

    A high-pressure in situ X-ray laminography technique was developed using a newly designed, laterally open diamond anvil cell. A low X-ray beam of 8 keV energy was used, aiming at future application to dual energy X-ray chemical imaging techniques. The effects of the inclination angle and the imaging angle range were evaluated at ambient pressure using the apparatus. Sectional images of ruby ball samples were successfully reconstructed at high pressures, up to approximately 50 GPa. The high-pressure in situ X-ray laminography technique is expected to provide new insights into the deep Earth sciences.

  9. Human Motion Tracking at Marshall Space Flight Center's Collaborative Engineering Center ANVIL

    NASA Technical Reports Server (NTRS)

    Henderson, Steven J.; Hamilton, George S.

    2004-01-01

    The installation and use of electromagnetic human motion trackers requires a specially designed and metal-free environment for optimal performance. Such an area is not readily available at the Marshall Space Flight Center Collaborative Engineering Center ANVIL. Our paper details a systems engineering approach to installing and operating Ascension Technologies Ethernet MotionStar tracking system in a sub-optimal environment, used with the JACK human computer model's motion capture capabilities. We also discuss how this system is integrated into the Marshall Space Flight Center's Human Engineering process.

  10. Diamond anvil cell radial x-ray diffraction program at the National Synchrotron Light Source.

    PubMed

    Hu, J Z; Mao, H K; Shu, J F; Guo, Q Z; Liu, H Z

    2006-06-28

    During the past decade, the radial x-ray diffraction method using a diamond anvil cell (DAC) has been developed at the X17C beamline of the National Synchrotron Light Source. The detailed experimental procedure used with energy dispersive x-ray diffraction is described. The advantages and limitations of using the energy dispersive method for DAC radial diffraction studies are also discussed. The results for FeO at 135 GPa and other radial diffraction experiments performed at X17C are discussed in this report.

  11. Cryogenic implementation of charging diamond anvil cells with H2 and D2

    NASA Astrophysics Data System (ADS)

    Chi, Zhenhua; Nguyen, Huyen; Matsuoka, Takahiro; Kagayama, Tomoko; Hirao, Naohisa; Ohishi, Yasuo; Shimizu, Katsuya

    2011-10-01

    A cryogenic loading system for introducing H2 and D2 into the diamond anvil cell has been designed and constructed. The integration of pressure loading mechanism, ruby fluorescence spectrometer, and microscope camera allows for in situ tuning and calibrating the pressure. The performance of the system has been demonstrated by successful synthesis of hydride and deuteride of transition metal and rare earth metal. Our cryogenic methodology features facile start-over of loading and in situ electrical resistance measurement of as-synthesized sample.

  12. Temperatures and aerosol opacities of the Mars atmosphere at aphelion: Validation and inter-comparison of limb sounding profiles from MRO/MCS and MGS/TES

    NASA Astrophysics Data System (ADS)

    Shirley, James H.; McConnochie, Timothy H.; Kass, David M.; Kleinböhl, Armin; Schofield, John T.; Heavens, Nicholas G.; McCleese, Daniel J.; Benson, Jennifer; Hinson, David P.; Bandfield, Joshua L.

    2015-05-01

    We exploit the relative stability and repeatability of the Mars atmosphere at aphelion for an inter-comparison of Mars Global Surveyor/Thermal Emission Spectrometer (MGS/TES) and Mars Reconnaissance Orbiter/Mars Climate Sounder (MRO/MCS) nighttime temperature profiles and aerosol opacity profiles in Mars years 25, 26, 29, 30, and 31. Cross-calibration of these datasets is important, as they together provide an extended climatology for this planetary atmosphere. As a standard of comparison we employ temperature profiles obtained by radio occultation methods during the MGS mission in Mars years 24, 25, and 26. We first compare both zonal mean TES limb sounding profiles and zonal mean MCS limb sounding profiles with zonal means of radio occultation temperature profiles for the same season (Ls = 70-80°) and latitudes (55-70°N). We employ a statistical z test for quantifying the degree of agreement of temperature profiles by pressure level. For pressures less than 610 Pa (altitudes > 3 km), the ensemble mean temperature difference between the radio occultation and TES limb sounding profiles found in these comparisons was 1.7 ± 0.7 K. The ensemble mean temperature difference between radio occultation and MCS profiles was 1.4 ± 1.0 K. These differences fall within the formal error estimates for both TES and MCS, validating the accuracy of the instruments and their respective retrieval algorithms. In the second phase of our investigation, we compare aphelion season zonal mean TES limb sounding temperature, water ice opacity, and dust opacity profiles with those obtained at the same latitudes in different years by MCS. The ensemble mean temperature difference found for three comparisons between TES and MCS zonal mean temperature profiles was 2.8 ± 2.1 K. MCS and TES temperatures between 610 Pa and 5 Pa from 55 to 70°N are largely in agreement (with differences < 2 K) when water ice aerosol opacities are comparable. Temperature differences increase when the opacities

  13. A diamond anvil cell with resistive heating for high pressure and high temperature x-ray diffraction and absorption studies.

    PubMed

    Pasternak, Sebastien; Aquilanti, Giuliana; Pascarelli, Sakura; Poloni, Roberta; Canny, Bernard; Coulet, Marie-Vanessa; Zhang, Lin

    2008-08-01

    In this paper we describe a prototype of a diamond anvil cell (DAC) for high pressure/high temperature studies. This DAC combines the use of a resistive oven of 250 W power in a very small volume, associated with special conical seats for Boehler-type diamond anvils in order to have a large angular acceptance. To protect the diamond anvils from burning and to avoid the oven oxidation, the heated DAC is enclosed in a vacuum chamber. The assemblage was used to study the melting curve of germanium at high pressure (up to 20 GPa) and high temperature (up to 1200 K) using x-ray diffraction and x-ray absorption spectroscopy.

  14. Pressure generation to 50 GPa in Kawai-type multianvil apparatus using newly developed tungsten carbide anvils

    NASA Astrophysics Data System (ADS)

    Kunimoto, Takehiro; Irifune, Tetsuo; Tange, Yoshinori; Wada, Kouhei

    2016-04-01

    A pressure generation test for Kawai-type multianvil apparatus (KMA) has been made using second-stage anvils of a newly developed ultra-hard tungsten carbide composite. Superb performance of the new anvil with significantly less plastic deformation was confirmed as compared to those commonly used for the KMA experiments. A maximum pressure of ∼48 GPa was achieved using the new anvils with a truncation edge length (TEL) of 1.5 mm, based on in situ X-ray diffraction measurements. Further optimization of materials and sizes of the pressure medium/gasket should lead to pressures even higher than 50 GPa in KMA using this novel tungsten carbide composite, which may also be used for expansion of the pressure ranges in other types of high pressure apparatus operated in large volume press.

  15. Synchrotron Studies Under Extreme Conditions: Tackling the Multi-Phase with the Multi-Anvil

    NASA Astrophysics Data System (ADS)

    Whitaker, M. L.; Chen, H.; Vaughan, M. T.; Weidner, D. J.

    2012-12-01

    Understanding the properties and behaviors of materials and multi-phase aggregates under conditions of high pressure and temperature are vital to unraveling the mysteries that lie beneath the surface of the planet. Advances in in situ experimental techniques utilizing synchrotron radiation at these extreme conditions have helped to provide answers to many fundamental questions that were previously unattainable. In particular, the Multi-Anvil apparatus has proven to be an invaluable tool for studying the morphological characteristics and physical properties of materials under extreme conditions as a function of pressure, temperature, stress, strain, and time. Moreover, the science is still continuing to evolve, and we have begun to step outside the realm of the static into the study of dynamic processes and their real-time responses to changes in the aforementioned variables, and even to the frequency and rate of these changes. This presentation will discuss the evolution and present state of the art in synchrotron-based multi-anvil techniques at the COMPRES-funded X17MAC Facility at the National Synchrotron Light Source, of which Professor R.C. Liebermann has been an integral player during his scientific career, and particularly during his tenure as President of COMPRES.

  16. Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

    SciTech Connect

    Kamojjala, Krishna; Lacy, Jeffrey; Chu, Henry S.; Brannon, Rebecca

    2015-03-01

    Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

  17. ANVIL neural network program for three-dimensional automatic target recognition

    NASA Astrophysics Data System (ADS)

    Thoet, William; Rainey, Timothy G.; Brettle, Dean W.; Slutz, Lee A.; Weingard, Fred

    1992-12-01

    The focus of the artificial neural vision learning (ANVIL) program is to apply neural network technologies to the air-to-surface 3-D automatic target recognition (ATR) problem. The 3-D multiple object detection and location system (MODALS) neural network was developed under the ANVIL program to simultaneously detect, locate, segment, and identify multiple targets. The performance results show a very high identification accuracy, a high detection rate, and a low false alarm rate, even for areas with high clutter and shadowing. The results are shown as detection/false alarm curves and identification/false alarm curves. In addition, positional detection accuracy is shown for various scale sizes. To provide data for the program, visible terrain board imagery was collected under a variety of background and lighting conditions. Tests were made on more than 500 targets of five types and two classes. These targets varied in scale by up to -25%, varied in azimuth by up to 120 deg, and varied in elevation by up to 10 deg. The performance results are shown for targets with resolution ranging from 9 to 700 pixels on target.

  18. High-temperature experiments using a resistively heated high-pressure membrane diamond anvil cell.

    PubMed

    Jenei, Zsolt; Cynn, Hyunchae; Visbeck, Ken; Evans, William J

    2013-09-01

    We describe a reliable high performance resistive heating method developed for the membrane diamond anvil cell. This method generates homogenous high temperatures at high pressure in the whole sample for extended operation period. It relies on two mini coil heaters made of Pt-Rh alloy wire mounted around the diamond anvils and gasket, while temperature is monitored by two K-type thermocouples mounted near the sample. The sample, diamonds, and tungsten-carbide seats are thermally insulated from the piston and cylinder keeping the cell temperature below 750 K while the sample temperature is 1200 K. The cell with the heaters is placed in a vacuum oven to prevent oxidation and unnecessary heat loss. This assembly allows complete remote operation, ideally suited for experiments at synchrotron facilities. Capabilities of the setup are demonstrated for in situ Raman and synchrotron x-ray diffraction measurements. We show experimental measurements from isothermal compression at 900 K and 580 K to 100 GPa and 185 GPa, respectively, and quasi-isobaric compression at 95 GPa over 1000 K.

  19. X-ray diffraction of periclase in a laser-heated diamond-anvil cell

    NASA Astrophysics Data System (ADS)

    Fiquet, G.; Andrault, D.; Itié, J. P.; Gillet, P.; Richet, P.

    1996-05-01

    Periclase (MgO) has been studied up to 16 GPa and temperatures in excess of 3000 K by X-ray diffraction in an energy-dispersive configuration at the DCI storage ring of LURE (Laboratoire pour l'Utilisation du Royonnement Electromagnétique, Orsay, France). The experiments were conducted in a diamond-anvil cell heated with a CO 2 laser with argon as a pressure transmitting medium. With this newly developed experimental set-up, the molar volume of periclase was measured as a function of pressure and temperature, which were both measured on-line. The thermal expansion coefficient (α) determined in these preliminary experiments has apparently too strong a pressure dependence, decreasing for instance from 4.9 10 -5 K -1 at room pressure to 7.5 10 -6 K -1 at 13.0 GPa. These results would yield a very high Anderson-Grüneisen parameter ( δT = 25-30), in disagreement with the expected δT = 6.5-4.3, as calculated for MgO or obtained by Fei et al. (1992a) on magnesiowüstite from room temperature to 900 K. This difference indicates that thermal pressure in the laser-heated spot can be significant and should be addressed in laser-heated diamond-anvil cell experiments.

  20. CRYSTAL-FACE: A Field Experiment and Modeling Program Focused on Tropical Anvils and Cirrus Layers

    NASA Technical Reports Server (NTRS)

    Jenson, Eric; Gore, Warren J. (Technical Monitor)

    2002-01-01

    The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) is a measurement campaign designed to investigate tropical Cirrus cloud physical properties and formation processes. Understanding the production of upper tropospheric cirrus clouds is essential for the successful modeling of 'he Earth's climate. The deployment phase will occur in July, 2002 in southern Florida, USA. Several aircraft will be used, including the ER-2 and Proteus for cloud remote sensing, the WB-57 and Citation for in situ cloud measurements, the P-3 with a Doppler radar for characterization of convective systems, and the Twin otter for sampling of inflow airmasses. In addition, numerous ground-based and satellite remote sensing measurements will be contributing. A central focus of the mission is improvement of our ability to model cirrus clouds with numerical models. Several research groups with a variety of model types (cloud-resolving models, mesoscale models, weather-prediction models, and general circulation models) will be participating. Our hope is to fully characterize several mulonimbus/cirrus anvil systems that can be used as case studies for testing and improvement of the models. The models will be used for investigating cirrus generation and dissipation processes and the sensitivity of tropical cirrus to convective intensity and aerosol properties. Ultimately, we expect this effort to improve our ability to represent tropical cirrus in GCMs. A general description of the CRYSTAL-FACE program will be presented, with an emphasis on the cloud modeling approach.

  1. CRYSTAL-FACE: A Field Experiment and Modeling Program Focused on Tropical Anvils and Cirrus Layers

    NASA Technical Reports Server (NTRS)

    Jenson, Eric; Gore, Warren J. (Technical Monitor)

    2002-01-01

    The Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) is a measurement campaign designed to investigate tropical Cirrus cloud physical properties and formation processes. Understanding the production of upper tropospheric cirrus clouds is essential for the successful modeling of 'he Earth's climate. The deployment phase will occur in July, 2002 in southern Florida, USA. Several aircraft will be used, including the ER-2 and Proteus for cloud remote sensing, the WB-57 and Citation for in situ cloud measurements, the P-3 with a Doppler radar for characterization of convective systems, and the Twin otter for sampling of inflow airmasses. In addition, numerous ground-based and satellite remote sensing measurements will be contributing. A central focus of the mission is improvement of our ability to model cirrus clouds with numerical models. Several research groups with a variety of model types (cloud-resolving models, mesoscale models, weather-prediction models, and general circulation models) will be participating. Our hope is to fully characterize several mulonimbus/cirrus anvil systems that can be used as case studies for testing and improvement of the models. The models will be used for investigating cirrus generation and dissipation processes and the sensitivity of tropical cirrus to convective intensity and aerosol properties. Ultimately, we expect this effort to improve our ability to represent tropical cirrus in GCMs. A general description of the CRYSTAL-FACE program will be presented, with an emphasis on the cloud modeling approach.

  2. Pressure mapping for sphere and half-sphere enhanced diamond anvil cells using synchrotron x-ray diffraction and fluorescence techniques

    NASA Astrophysics Data System (ADS)

    Liu, H.; Liu, L. L.; Cai, Z.; Shu, J.

    2015-12-01

    The measurement for equation of state (EoS) of materials under pressure conditions above 200 GPa is a long-standing challenging subject. Recently, second stage anvil, which was loaded inside the diamond anvil cell (DAC), had been reported by various groups. This method could generate pressure over 300 GPa, or above 600 GPa from the EoS measurement of Re metal between the tiny anvil or 2 half-spheres. Several alternative approaches, using ruby balls, or glassy carbon, or diamond, with single sphere, 2 half-spheres, or multi spheres geometry inside DAC, were tested. The NIST X-ray powder standard, ZnO was selected as pressure marker. Focused ion beam (FIB) was used to cut the half-sphere from diamond anvil top directly to avoid the difficulty of alignment. The synchrotron x-ray diffraction with fine beam size down to 100 nm using zone plate set-up was used to map the pressure gradient at the sphere or half-sphere zone inside DAC. The pressure could be boosted at center of sphere by up to 10 - 70 GPa at about 200 GPa conditions. From broken anvils, trace element analysis using fine focusing synchrotron x-ray fluorescence method revealed the potential anvil damage from FIB cutting the diamond anvil tip, which might decrease the strength of anvils. Fine touch from FIB cutting at final stage using low ion beam current is suggested.

  3. MCS-18, a natural product isolated from Helleborus purpurascens, inhibits maturation of dendritic cells in ApoE-deficient mice and prevents early atherosclerosis progression.

    PubMed

    Dietel, Barbara; Muench, Rabea; Kuehn, Constanze; Kerek, Franz; Steinkasserer, Alexander; Achenbach, Stephan; Garlichs, Christoph D; Zinser, Elisabeth

    2014-08-01

    Inflammation accelerates both plaque progression and instability in the pathogenesis of atherosclerosis. The inhibition of dendritic cell (DC) maturation is a promising approach to suppress excessive inflammatory immune responses and has been shown to be protective in several autoimmune models. The aim of this study was to investigate the immune modulatory effects of the natural substance MCS-18, an inhibitor of DC maturation, regarding the progression of atherosclerosis in ApoE-deficient mice. ApoE-deficient mice were fed for twelve weeks with a Western-type diet (n = 32) or normal chow (control group; n = 16). Animals receiving high-fat diet were treated with MCS-18 (500 μg/kg body weight, n = 16) or saline (n = 16) twice a week. After 12 weeks, animals were transcardially perfused and sacrificed. The percentage of mature DCs (CD3(-)/CD19(-)/CD14(-)/NK1.1(-)/CD11c(+)/MHCII(+)/CD83(+)/CD86(+)) and T cell subpopulations (CD4(+)/CD25(+)/Foxp3(+), CD3/CD4/CD8) was analyzed in peripheral blood and in the spleen using flow cytometry. Plaque size was determined in the aortic root and the thoracoabdominal aorta using en-face staining. Immunohistochemical stainings served to detect inflammatory cells in the aortic root. Several cytokines and chemokines were determined in serum using multiplex assays. In splenic cells derived from saline-treated atherosclerotic mice an increased DC maturation, reflected by the upregulation of CD83 and CD86 expression, was observed. The enhanced expression of both maturation markers was absent in MCS-18 treated atherosclerotic mice. While the percentage of splenic Foxp3 expressing Treg was increased in animals receiving MCS-18 compared to saline-treated atherosclerotic mice, cytotoxic T cells were reduced in the spleen and in atherosclerotic lesions of the aortic root. Furthermore, proatherogenic cytokines (e.g. IL-6 and IFN-γ) and chemokines (e.g. MIP-1β) were decreased in serum of MCS-18-treated animals when compared to saline

  4. Constraining mass-diameter relations from hydrometeor images and cloud radar reflectivities in tropical continental and oceanic convective anvils

    NASA Astrophysics Data System (ADS)

    Fontaine, E.; Schwarzenboeck, A.; Delanoë, J.; Wobrock, W.; Leroy, D.; Dupuy, R.; Gourbeyre, C.; Protat, A.

    2014-10-01

    In this study the density of ice hydrometeors in tropical clouds is derived from a combined analysis of particle images from 2-D-array probes and associated reflectivities measured with a Doppler cloud radar on the same research aircraft. Usually, the mass-diameter m(D) relationship is formulated as a power law with two unknown coefficients (pre-factor, exponent) that need to be constrained from complementary information on hydrometeors, where absolute ice density measurement methods do not apply. Here, at first an extended theoretical study of numerous hydrometeor shapes simulated in 3-D and arbitrarily projected on a 2-D plan allowed to constrain the exponent βof the m(D) relationship from the exponent σ of the surface-diameterS(D)relationship, which is likewise written as a power law. Since S(D) always can be determined for real data from 2-D optical array probes or other particle imagers, the evolution of the m(D) exponent can be calculated. After that, the pre-factor α of m(D) is constrained from theoretical simulations of the radar reflectivities matching the measured reflectivities along the aircraft trajectory. The study was performed as part of the Megha-Tropiques satellite project, where two types of mesoscale convective systems (MCS) were investigated: (i) above the African continent and (ii) above the Indian Ocean. For the two data sets, two parameterizations are derived to calculate the vertical variability of m(D) coefficients α and β as a function of the temperature. Originally calculated (with T-matrix) and also subsequently parameterized m(D) relationships from this study are compared to other methods (from literature) of calculating m(D) in tropical convection. The significant benefit of using variable m(D) relations instead of a single m(D) relationship is demonstrated from the impact of all these m(D) relations on Z-CWC (Condensed Water Content) and Z-CWC-T-fitted parameterizations.

  5. Initial results from Ensemble Data Assimilation of radiances and retrieved temperatures from TES and MCS in an Martian GCM

    NASA Astrophysics Data System (ADS)

    Lee, C.; Richardson, M. I.

    2010-12-01

    Direct observations of the Martian atmosphere are used to constrain the evolution of a Martian General Circulation Model (MarsWRF) using an ensemble Kalman filter data assimilation framework (DART). We use radiance observations from the Thermal Emission Spectrometer (TES) and temperature profiles from TES and the Mars Climate Sounder (MCS) to constrain the evolution of the simulated Martian atmosphere during similar seasons of each mission. We describe the observations being ingested into the model and the preprocessing necessary to ingest these observations efficiently and accurately into the assimilation system. We test the sensitivity of the assimilation system by including surface visual albedo and infra-red emissivity, and atmospheric total dust loading, in the state vector. We allow DART to modify these unobserved state vector components using only the temperature or radiance observations and information gained from the ensemble of simulated circulations. Finally, we identify and discuss the biases and model limitations revealed by the assimilation, and describe the modifications made to the GCM to improve its ensemble mean skill (accuracy) and ensemble variance to better assimilate the available observations.

  6. Characterization of the submesoscale energy cascade in the Alboran Sea thermocline from spectral analysis of high-resolution MCS data

    NASA Astrophysics Data System (ADS)

    Sallares, Valenti; Mojica, Jhon F.; Biescas, Berta; Klaeschen, Dirk; Gràcia, Eulàlia

    2016-06-01

    Part of the kinetic energy that maintains ocean circulation cascades down to small scales until it is dissipated through mixing. While most steps of this downward energy cascade are well understood, an observational gap exists at horizontal scales of 103-101 m that prevents characterizing a key step in the chain: the transition from anisotropic internal wave motions to isotropic turbulence. Here we show that this observational gap can be covered using high-resolution multichannel seismic (HR-MCS) data. Spectral analysis of acoustic reflectors imaged in the Alboran Sea thermocline shows that this transition is likely caused by shear instabilities. In particular, we show that the averaged horizontal wave number spectra of the reflectors vertical displacements display three subranges that reproduce theoretical spectral slopes of internal waves (λx > 100 m), Kelvin-Helmholtz-type shear instabilities (100 m > λx > 33 m), and turbulence (λx < 33 m), indicating that the whole chain of events is occurring continuously and simultaneously in the surveyed area.

  7. Advanced Synchrotron Technique for Synthesis and Analysis of Polyhydrides in the Laser Heated Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Prakapenka, V.; Struzhkin, V.; Goncharov, A. F.; Greenberg, E.

    2016-12-01

    To understand the complex nature of the deep interior of the terrestrial and giant planets the essential properties of a wide range of minerals must be studied in-situ at relevant ultra-extreme conditions of pressure and temperature. One of the most challenging high pressure high temperature experiments with the diamond anvil cell is related to a laser heating technique combined with synchrotron x-ray diffraction (XRD) and spectroscopy [1]. Especially it is crucial for compression of materials which affect the stability of diamond anvils even at ambient temperature, resulting in experiment failure. Hydrogen and/or alkali metals and their compounds are such examples. Typically, such type of experiments should be carried out at low temperatures in a bulky cryostat with limited flexibility on temperature variation and with restricted optical and x-ray access. At GSECARS we have developed a method that allows us to compress samples at cryo-temperatures while maintaining a relatively short optical working distance to implement laser heating, optical spectroscopy combined with XRD for in-situ high pressure and low/high temperature analysis. We have used an Oxford Cryosteam system to generate a nitrogen jet pointed directly at the sample to cool it down below 150K (typically 115K) as well as to protect the back side of the diamond anvils from frost. While the DAC was kept at cryo-temperatures the "burst" laser heating technique was used to synthesize new compounds and probe in-situ high temperature properties of samples with high resolution synchrotron XRD. With this technique we have successfully studied a number of hydrogen compounds in the megabar pressure range. For example, hydrogen-rich hydrides of Na (NaH3 and NaH7) were synthesized for the first time and studied at pressure-temperature conditions above 30 GPa and 2,000 K [2]. Hydrogen sulfide (H2S) was studied by synchrotron XRD and Raman spectroscopy up to 150 GPa at 180-295 K [3]. The described above new method

  8. Tropical deep convective life cycle: Cb-anvil cloud microphysics from high-altitude aircraft observations

    NASA Astrophysics Data System (ADS)

    Frey, W.; Borrmann, S.; Fierli, F.; Weigel, R.; Mitev, V.; Matthey, R.; Ravegnani, F.; Sitnikov, N. M.; Ulanovsky, A.; Cairo, F.

    2014-12-01

    The case study presented here focuses on the life cycle of clouds in the anvil region of a tropical deep convective system. During the SCOUT-O3 campaign from Darwin, Northern Australia, the Hector storm system has been probed by the Geophysica high-altitude aircraft. Clouds were observed by in situ particle probes, a backscatter sonde, and a miniature lidar. Additionally, aerosol number concentrations have been measured. On 30 November 2005 a double flight took place and Hector was probed throughout its life cycle in its developing, mature, and dissipating stage. The two flights were four hours apart and focused on the anvil region of Hector in altitudes between 10.5 and 18.8 km (i.e. above 350 K potential temperature). Trajectory calculations, satellite imagery, and ozone measurements have been used to ensure that the same cloud air masses have been probed in both flights. The size distributions derived from the measurements show a change not only with increasing altitude but also with the evolution of Hector. Clearly different cloud to aerosol particle ratios as well as varying ice crystal morphology have been found for the different development stages of Hector, indicating different freezing mechanisms. The development phase exhibits the smallest ice particles (up to 300 μm) with a rather uniform morphology. This is indicative for rapid glaciation during Hector's development. Sizes of ice crystals are largest in the mature stage (larger than 1.6 mm) and even exceed those of some continental tropical deep convective clouds, also in their number concentrations. The backscatter properties and particle images show a change in ice crystal shape from the developing phase to rimed and aggregated particles in the mature and dissipating stages; the specific shape of particles in the developing phase cannot be distinguished from the measurements. Although optically thin, the clouds in the dissipating stage have a large vertical extent (roughly 6 km) and persist for at

  9. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially-grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in the experiment the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp→αSm transition proceeds in discontinuous steps at points along the expected phase boundary. Additionally, the unit cell volumes of each phase deviate from the expected thermal expansion behavior just before each transition is observed from the diffraction data. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0 - 10 GPa and 300 - 650 K.

  10. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Vohra, Y. K.; Velisavljevic, N.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10 GPa and 300–650 K.

  11. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    SciTech Connect

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; Vohra, Y. K.

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K

  12. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    DOE PAGES

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; ...

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8GPa and 600K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high-pressure area on the order of a few tens of seconds. This device is then used to scan the phasemore » diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in this experiment, the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp → αSm transition proceeds in discontinuous steps at points along the expected phase boundary. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0–10GPa and 300–650K« less

  13. Spectroscopy at very high pressures. 14: Laser Raman scattering in ultrasmall samples in a diamond anvil cell.

    PubMed

    Adams, D M; Sharma, S K; Appleby, R

    1977-09-01

    The problem of obtaining Raman spectra at high pressures with a diamond anvil cell is analyzed, and the successful use of a 90 degrees off-axis ellipsoidal mirror for collection in both 0 degrees and 180 degrees scattering modes is demonstrated with nu(OH) spectra of ice VI, VII, and vIII.

  14. Implementation of micro-ball nanodiamond anvils for high-pressure studies above 6 Mbar

    PubMed Central

    Dubrovinsky, Leonid; Dubrovinskaia, Natalia; Prakapenka, Vitali B; Abakumov, Artem M

    2012-01-01

    Since invention of the diamond anvil cell technique in the late 1950s for studying materials at extreme conditions, the maximum static pressure generated so far at room temperature was reported to be about 400 GPa. Here we show that use of micro-semi-balls made of nanodiamond as second-stage anvils in conventional diamond anvil cells drastically extends the achievable pressure range in static compression experiments to above 600 GPa. Micro-anvils (10–50 μm in diameter) of superhard nanodiamond (with a grain size below ∼50 nm) were synthesized in a large volume press using a newly developed technique. In our pilot experiments on rhenium and gold we have studied the equation of state of rhenium at pressures up to 640 GPa and demonstrated the feasibility and crucial necessity of the in situ ultra high-pressure measurements for accurate determination of material properties at extreme conditions. PMID:23093199

  15. High-pressure high temperature generation over 40 GPa using Kwai-type multianvil apparatus with carbide anvils

    NASA Astrophysics Data System (ADS)

    Ishii, T.; Shi, L.; Miyajima, N.; Boffa Ballaran, T.; Sinmyo, R.; Kawazoe, T.; Katsura, T.

    2015-12-01

    Kawai-type multianvil apparatus are widely used as high-pressure devices to generate pressures to the uppermost lower mantle using tungsten carbide (WC) anvils. Combination with sintered diamond (SD) anvils allows generating pressure above 30 to usually 60 GPa. However, it is difficult to use SD anvils practically, because they are much expensive than WC anvils. We therefore developed experimental techniques to generate pressures over 40 GPa using a Kawai-type apparatus with WC anvils particularly for studying phase relations in multi-component systems in the lower mantle down to 1000 km depth. We used a 15-MN Kawai-type multianvil apparatus with DIA-type guide blocks with careful optimization of a cubic compression space formed by first-stage anvils. Pressures were generated using hard WC anvils (TF05, Fujilloy Co., Ltd) with truncation of 1.5 mm and taper of 1.0ᴼ with a semi-sintered MgO + 5wt.%Cr2O3 octahedron as a pressure medium. Pressure was calibrated by detecting resistance changes of Bi, ZnS, GaP and Zr at room temperature. The maximum achievable pressure at 2000 K, which was generated using a Re heater in a LaCrO3 thermal insulator, was examined by the Al2O3 content in aluminous bridgemanite. Al2O3 rods were placed at the both side of the sample in a furnace. The starting material was sintered ilmenite-type Mg3Al2Si3O12 synthesized at 1200 K and 26 GPa (Kubo and Akaogi, 2000). We observed the ω-β transition in Zr (34 GPa) (Ono and Kikegawa, 2015) at a press load of 8 MN at room temperature. The sample synthesized at 2000 K and 15 MN has a composition nearly equal to pyrope and the LiNbO3-type structure. The LiNbO3 structure of the recovered sample with pyrope composition suggests that it had the perovskite structure before recovery. The composition of this sample suggests generation of 44 GPa at a high temperature of 2000 K, according to the phase relations in the MgSiO3-Al2O3 system (Liu, private communication).

  16. Quality of life in patients with systemic lupus erythematosus (SLE) compared with related controls within a unique African American population.

    PubMed

    Barnado, A; Wheless, L; Meyer, A K; Gilkeson, G S; Kamen, D L

    2012-04-01

    The patient's perspective of how their health affects their function is health-related quality of life (HRQOL). HRQOL is poorer in patients with systemic lupus erythematosus (SLE). Few HRQOL studies in SLE patients have focused on African Americans despite an increased disease burden compared with Caucasians. The African American Gullah population of South Carolina has a homogeneous genetic and environmental background and a high prevalence of multi-patient families with SLE. Demographics, medical history, and Short-Form 36 (SF-36) were measured within a cohort of Gullah SLE cases and related controls. Compared with related controls (n = 37), cases (n = 89) had a lower Physical Component Summary (PCS, 41.8 vs. 52.3, p < 0.01), but not Mental Component Summary (MCS, 55.0 vs. 56.0, p = 0.70). The difference in PCS was no longer significant upon adjustment for working status, disability, and medical conditions. None of the 11 SLE American College of Rheumatology criteria, disease duration, or Systemic Lupus International Collaborating Clinics Damage Index were associated with either PCS or MCS. Cases and controls had similar MCS scores. We hypothesize that this lack of effect of SLE on MCS may be due to disease-coping mechanisms interplaying with cultural factors unique to the Gullah.

  17. Novel diamond cells for neutron diffraction using multi-carat CVD anvils.

    PubMed

    Boehler, R; Molaison, J J; Haberl, B

    2017-08-01

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ∼0.15 mm(3). High quality spectra were obtained in 1 h for crystalline Ni and in ∼8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

  18. High-Temperature Experiments using a Resistively-Heated High-Pressure Membrane Diamond Anvil Cell

    SciTech Connect

    Jenei, Z; Visbeck, K; Cynn, H; Yoo, C; Evans, W

    2009-04-22

    A reliable high-performance heating method using resistive heaters and a membrane driven diamond anvil cell (mDAC) is presented. Two micro-heaters are mounted in a mDAC and use electrical power of less than 150 W to achieve sample temperatures up to 1200 K. For temperature measurement we use two K-type thermocouples mounted near the sample. The approach can be used for in-situ Raman spectroscopy and x-ray diffraction at high pressures and temperatures. A W-Re alloy gasket material permits stable operation of mDAC at high temperature. Using this method, we made an isothermal compression at 900 K to pressures in excess of 100 GPa and isobaric heating at 95 GPa to temperatures in excess of 1000 K. As an example, we present high temperature Raman spectroscopy measurements of nitrogen at high pressures.

  19. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    NASA Astrophysics Data System (ADS)

    Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  20. Material transport in laser-heated diamond anvil cell melting experiments

    NASA Technical Reports Server (NTRS)

    Campbell, Andrew J.; Heinz, Dion L.; Davis, Andrew M.

    1992-01-01

    A previously undocumented effect in the laser-heated diamond anvil cell, namely, the transport of molten species through the sample chamber, over distances large compared to the laser beam diameter, is presented. This effect is exploited to determine the melting behavior of high-pressure silicate assemblages of olivine composition. At pressures where beta-spinel is the phase melted, relative strengths of partitioning can be estimated for the incompatible elements studied. Iron was found to partition into the melt from beta-spinel less strongly than calcium, and slightly more strongly than manganese. At higher pressures, where a silicate perovskite/magnesiowuestite assemblage is melted, it is determined that silicate perovskite is the liquidus phase, with iron-rich magnesiowuestite accumulating at the end of the laser-melted stripe.

  1. Miniature diamond anvil cell for broad range of high pressure measurements.

    PubMed

    Gavriliuk, A G; Mironovich, A A; Struzhkin, V V

    2009-04-01

    A miniature versatile nonmagnetic diamond anvil cell for diverse physical property measurement under cryogenic environments and high magnetic fields at high pressure has been developed. Several such cells have been manufactured and tested in the Physical Properties Measurement System (PPMS) by Quantum Design at high pressures and low temperatures. The cells have good pressure stability during temperature scans down to helium temperatures and back to room temperature. The cells have been tested in strong magnetic fields and demonstrated excellent nonmagnetic properties. The wide-angle side openings give the possibility to use this cell as a "panoramic cell" in synchrotron experiments requiring large angle off-axis access. The possible experiments, which may use this cell, include spectroscopic experiments (optical, synchrotron Mossbauer, Raman, x-ray emission, etc.), different types of x-ray diffraction experiments, transport measurements (resistivity, magnetoresistivity, thermoelectromotive force, etc.), measurements of susceptibility, and many other conventional and synchrotron experiments at very low temperatures and in strong magnetic fields.

  2. Resistance heating of Fe and W in diamond-anvil cells

    NASA Technical Reports Server (NTRS)

    Boehler, R.; Nicol, M.; Zha, C. S.; Johnson, M. L.

    1986-01-01

    A new method for internally heating a diamond-anvil cell is described. Fine wires of iron or tungsten are resistively heated in a gasketed cell, thus providing a uniformly distributed pressure that can be measured in situ by employing the ruby scale. Temperatures of several thousand degrees have been measured by fitting a black body radiation function to the spectrum of the hot wire taken with an optical multichannel analyzer. Temperatures as high as the melting temperature of tungsten have been achieved. The alpha-gamma and alpha-epsilon phase transitions of iron have been studied, and the results show excellent agreement with previous data obtained with piston-cylinder or externally-heated diamond cells.

  3. Phase transitions in ammonium perchlorate to 26 GPA and 700 K in a diamond anvil cell

    SciTech Connect

    Foltz, M.F.; Maienschein, J.L.

    1996-05-01

    Ammonium perchlorate (AP) showed previously unreported phase behavior when studied in a diamond anvil cell (DAC) at high temperature (to 693 K) and high pressure (to {approximately}26 GPa). Liquid droplets, observed above the known 513 K orthorhombic-to-cubic phase transition, are interpreted as the onset to melting. The melting point decreased with increasing pressure. Mid-infrared FTIR spectra of the residue showed only AP. The AP melt may contribute to shock insensitivity of AP-based propellants. Gas formation was seen at higher temperatures. A phase diagram was constructed using the appearance of liquid and gas as solid-liquid and liquid-gas transitions. Preliminary pressurized differential scanning calorimetry data showed a weak pressure dependence (to {approximately}6.9MPa) for the orthorhombic-to-cubic phase transition. {copyright} {ital 1996 American Institute of Physics.}

  4. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    SciTech Connect

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  5. Phase transitions in ammonium perchlorate to 26 GPA and 700 K in a diamond anvil cell

    SciTech Connect

    Foltz, M.F.; Maienschein, J.L.

    1995-07-10

    Ammonium perchlorate (AP) showed previously unreported phase behavior when studied in a diamond anvil cell (DAC) at high temperature (to 693 K) and high pressure (to {approximately}26 GPa). Liquid droplets, observed above the known 513 K orthorhombic-to-cubic phase transition, are interpreted as the onset to melting. The melting point decreased with increasing pressure. Mid-infrared FTIR spectra of the residue showed only AP. The AP melt may contribute to shock insensitivity of AP-based propellants. Gas formation was seen at higher temperatures. A phase diagram was constructed using the appearance of liquid and gas as solid-liquid and liquid-gas transitions. Preliminary pressurized differential scanning calorimetry data showed a weak pressure dependence (to {approximately}6.9 MPa) for the orthorhombic-to-cubic phase transition.

  6. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability.

    PubMed

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Yishu; Jaramillo, R; Banerjee, A; Ren, Y; Rosenbaum, T F

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  7. Single-wall carbon nanotubes under high pressures to 62 GPa studied using designer diamond anvils.

    PubMed

    Patterson, J R; Vohra, Y K; Weir, S T; Akella, J

    2001-06-01

    Single-wall carbon nanotube samples were studied under high pressures to 62 GPa using designer diamond anvils with buried electrical microprobes that allowed for monitoring of the four-probe electrical resistance at elevated pressure. After initial densification, the electrical resistance shows a steady increase from 3 to 42 GPa, followed by a sharp rise above 42 GPa. This sharp rise in electrical resistance at high pressures is attributed to opening of an energy band gap with compression. Nanoindentation hardness measurements on the pressure-treated carbon nanotube samples gave a hardness value of 0.50 +/- 0.03 GPa. This hardness value is approximately 2 orders of magnitude lower than the amorphous carbon phase produced in fullerenes under similar conditions. Therefore, the pressure treatment of single-wall carbon nanotubes to 62 GPa did not produce a superhard carbon phase.

  8. Density measurement of samples under high pressure using synchrotron microtomography and diamond anvil cell techniques

    PubMed Central

    Xiao, Xianghui; Liu, Haozhe; Wang, Luhong; De Carlo, Francesco

    2010-01-01

    Accurate mass density information is critical in high-pressure studies of materials. It is, however, very difficult to measure the mass densities of amorphous materials under high pressure with a diamond anvil cell (DAC). Employing tomography to measure mass density of amorphous samples under high pressure in a DAC has recently been reported. In reality, the tomography data of a sample in a DAC suffers from not only noise but also from the missing angle problem owing to the geometry of the DAC. An algorithm that can suppress noise and overcome the missing angle problem has been developed to obtain accurate mass density information from such ill-posed data. The validity of the proposed methods was supported with simulations. PMID:20400834

  9. Characteristics of silicone fluid as a pressure transmitting medium in diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Shen, Yongrong; Kumar, Ravhi S.; Pravica, Michael; Nicol, Malcolm F.

    2004-11-01

    The properties of a silicone fluid with initial viscosity of 1 cst as a pressure transmitting medium for diamond anvil cells have been determined by ruby R1 line broadening and R1-R2 separation measurements to 64 GPa at ambient temperature. By these criteria, the silicone fluid is as good a pressure medium as a 4:1 methanol:ethanol mixture at low pressures to about 20 GPa, and is better than the mixture at higher pressures. Although argon media are better than the silicone at pressures to 30 GPa, this silicone behaves as well as argon at higher pressures. Furthermore, the silicone is easier to load than argon and is almost chemically inert.

  10. Pressure concentrations due to plastic deformation of thin films or gaskets between anvils

    NASA Technical Reports Server (NTRS)

    Chan, K. S.; Huang, T. L.; Grzybowski, T. A.; Whetten, T. J.; Ruoff, A. L.

    1982-01-01

    Plastic deformation of either a sample or a gasket between diamond anvils leads to large pressure concentrations, i.e., the maximum pressure can be many times the average pressure. This behavior is discussed using elementary plasticity theory for the case where the pressures are sufficiently low that the yield stress can be assumed not to vary with pressure. It is then shown that the pressure concentration factor can be even much larger when the yield stress of the sample at the highest pressure is much greater than the yield stress at the lowest pressure. This is illustrated with solid xenon where it is shown that the assumption that Nelson and Ruoff made about the pressure distribution in their xenon samples is incorrect. The pressure distribution is shown to be much steeper than assumed. Thus, the pressure they observed electrical conduction in xenon was above 1 Mbar.

  11. Novel diamond cells for neutron diffraction using multi-carat CVD anvils

    NASA Astrophysics Data System (ADS)

    Boehler, R.; Molaison, J. J.; Haberl, B.

    2017-08-01

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ˜0.15 mm3. High quality spectra were obtained in 1 h for crystalline Ni and in ˜8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

  12. Explosive fragmentation of oil shale: Results from Colony and Anvil Points Mines, Colorado

    SciTech Connect

    Dick, R.D.; Fourney, W.L.; Young, C. III

    1992-12-31

    From 1978 through 1983, numerous oil shale fragmentation tests were conducted at the Colony and Anvil Points Mines, Colorado. These experiments were part of an investigation to determine factors required for the adequate fragmentation of oil shale and to evaluate the feasibility of using the vertical modified in situ retort (VMIS) method for recovery of kerogen from oil shale. The objective of this research was to support the design of a large volume (10{sup 4} m{sup 3}) rubble bed for in situ processing. In addition, this rubble bed was to be formed in a large single-blast event which included decked charges, time delays, and multiple boreholes. Results are described.

  13. Novel diamond cells for neutron diffraction using multi-carat CVD anvils

    DOE PAGES

    Boehler, R.; Molaison, J. J.; Haberl, Bianca

    2017-08-17

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ~0.15 mm3. High quality spectra weremore » obtained in 1 h for crystalline Ni and in ~8 h for disordered glassy carbon. In conclusion, these new techniques will open the way for routine megabar neutron diffraction experiments.« less

  14. Novel diamond cells for neutron diffraction using multi-carat CVD anvils

    DOE PAGES

    Boehler, R.; Molaison, J. J.; Haberl, B.

    2017-08-17

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed in this paper new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ~0.15 mm3. Highmore » quality spectra were obtained in 1 h for crystalline Ni and in ~8 h for disordered glassy carbon. Finally, these new techniques will open the way for routine megabar neutron diffraction experiments.« less

  15. Characteristics of anvil-top associated with the Poplar Bluff tornado of 7 May 1973

    NASA Technical Reports Server (NTRS)

    Pearl, E. W.

    1973-01-01

    Investigation of potential tornado-producing thunderstorms was performed during part of the 1972 and 1973 tornado seasons. On May 7, 1973 twenty-one tornadoes were confirmed over southern Missouri, northern Arkansas, and southwestern Illinois. The region was surveyed by high altitude photography performed on a Learjet over the region of reported tornadoes. Two storms were chosen from aircraft observation with the guidance of ground and radar reports, and a series of photographs were taken of a tornado producing cloud. An analysis of the activity before and during the tornado is made, and most noteworthy were changes detected in the growth and collapse of overshooting domes above the anvil. Suggestions are included for a comprehensive study.

  16. Conically shaped single-crystalline diamond backing plates for a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Krauss, G.; Reifler, H.; Steurer, W.

    2005-10-01

    Based on computer-aided design (CAD) and finite-element calculations (FEM), single-crystalline diamond backing plates were tailored as a replacement of beryllium for high-pressure diamond anvil cells with a focus on in-house single-crystal experiments. Although the modified cell has an opening angle of 90°, a very homogeneous stress distribution all over the backing plate was realized to avoid failure. The conically shaped backing plates work well in the targeted pressure range up to Mg2Co3Sn10.15 up to 9.69 GPa. The influence of simultaneous diffraction phenomena in the diamonds (diamond dips) is illustrated by single-counter and area-detector measurements using standard laboratory equipment.

  17. The birth and development of laser heating in diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Bassett, William A.

    2001-02-01

    In 1968 Taro Takahashi and I observed a phase transition that resulted from laser heating under pressure in a diamond anvil cell. Using a ruby laser, we successfully converted graphite to diamond. We soon realized that the ruby laser had such limited capabilities that we acquired a yttrium-aluminum-garnet (YAG) laser that could be used in both continuous and pulsed modes. The road to successfully applying the technique was not without a few bumps. Thirty years later, these seem more amusing than they did at the time. It was with the YAG laser that Ming and Liu investigated a number of silicate phase transitions important to our understanding of the earth's mantle. Since then it has been gratifying to watch as others have adopted the technique and made many important contributions with it.

  18. Low temperature system for a large volume multi-anvil press

    NASA Astrophysics Data System (ADS)

    Secco, Richard A.; Yong, Wenjun

    2016-12-01

    A new custom-designed system for a 3000 ton multi-anvil press has been developed to reach temperatures below room temperature at high pressures. The system was designed to remove heat selectively and conductively from the sample volume through six of the eight tungsten carbide (WC) cubes in direct contact with the octahedral pressure cell. The key components of the system include Cu cooling fins sandwiched between neighboring cube faces and the connected Cu heat exchange chamber through which liquid nitrogen flows. Currently, this system enables us to reach temperatures down to 220 K at pressures up to 8 GPa, but it can be easily modified to retain similar cooling capability at the highest pressure the press can reach (ca. 25 GPa).

  19. Resistance heating of Fe and W in diamond-anvil cells

    NASA Technical Reports Server (NTRS)

    Boehler, R.; Nicol, M.; Zha, C. S.; Johnson, M. L.

    1986-01-01

    A new method for internally heating a diamond-anvil cell is described. Fine wires of iron or tungsten are resistively heated in a gasketed cell, thus providing a uniformly distributed pressure that can be measured in situ by employing the ruby scale. Temperatures of several thousand degrees have been measured by fitting a black body radiation function to the spectrum of the hot wire taken with an optical multichannel analyzer. Temperatures as high as the melting temperature of tungsten have been achieved. The alpha-gamma and alpha-epsilon phase transitions of iron have been studied, and the results show excellent agreement with previous data obtained with piston-cylinder or externally-heated diamond cells.

  20. Material transport in laser-heated diamond anvil cell melting experiments

    NASA Technical Reports Server (NTRS)

    Campbell, Andrew J.; Heinz, Dion L.; Davis, Andrew M.

    1992-01-01

    A previously undocumented effect in the laser-heated diamond anvil cell, namely, the transport of molten species through the sample chamber, over distances large compared to the laser beam diameter, is presented. This effect is exploited to determine the melting behavior of high-pressure silicate assemblages of olivine composition. At pressures where beta-spinel is the phase melted, relative strengths of partitioning can be estimated for the incompatible elements studied. Iron was found to partition into the melt from beta-spinel less strongly than calcium, and slightly more strongly than manganese. At higher pressures, where a silicate perovskite/magnesiowuestite assemblage is melted, it is determined that silicate perovskite is the liquidus phase, with iron-rich magnesiowuestite accumulating at the end of the laser-melted stripe.

  1. Summary of the oil shale fragmentation program at Anvil Points Mine, Colorado

    SciTech Connect

    Dick, R.D.; Young, C.; Fourney, W.L.

    1984-01-01

    During 1981 and 1982, an extensive oil shale fragmentation research program was conducted at the Anvil Points Mine near Rifle, Colorado. The primary goals were to investigate factors involved for adequate fragmentation of oil shale and to evaluate the feasibility of using the modified in situ retort (MIS) method for recovery of oil from oil shale. The test program included single-deck, single-borehole tests to obtain basic fragmentation data; multiple-borehole, multiple-deck explosive tests to evaluate practical aspects for developing an in situ retort; and the development of a variety of instrumentation techniques to diagnose the blasting event. This paper will present an outline of the field program, the type of instrumentation used, some typical results from the instrumentation, and a discussion of explosive engineering problems encountered over the course of the program. 4 references, 21 figures, 1 table.

  2. High pressure Moissanite-anvil cells for the low temperature Hall effect measurements of oxide superconductors

    NASA Astrophysics Data System (ADS)

    Yomo, Shusuke; Tozer, Stanley

    2013-03-01

    The Hall effect was successfully measured for a single crystal of high temperature superconductor in a Moissanite-anvil clamp cell up to 5 GPa, with proper arrangement of lead wires and a sample. Zylon gasket, good in electrical insulation, worked well up to 5 GPa. The 30-40 % increase of the clamped pressure was observed during cooling to below 60 K. The appreciable pressure effect of the a-b plane Hall coefficient was observed and negative for La2 - x Srx CuO4 with x = 0.090. The result is discussed with those for sintered samples and those studied with a different pressurizing method. Thanks are due to Visiting Scientist Program, NHMFL, and NNSA grant DE-FG52-03NA00066.

  3. Novel diamond cells for neutron diffraction using multi-carat CVD anvils

    DOE PAGES

    Boehler, R.; Molaison, J. J.; Haberl, B.

    2017-08-17

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. Some main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ~0.15 mm3. We obtained high qualitymore » spectra in 1 h for crystalline Ni and in ~8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.« less

  4. Apparatus and Techniques for Time-resolved Synchrotron X-ray Diffraction using Diamond Anvil Cells

    NASA Astrophysics Data System (ADS)

    Smith, J.; Sinogeikin, S. V.; Lin, C.; Rod, E.; Bai, L.; Shen, G.

    2015-12-01

    Complementary advances in synchrotron sources, x-ray optics, area detectors, and sample environment control have recently made possible many time-resolved experimental techniques for studying materials at extreme pressure and temperature conditions. The High Pressure Collaborative Access Team (HPCAT) at the Advanced Photon Source has made a sustained effort to assemble a powerful collection of high-pressure apparatus for time-resolved research, and considerable time has been invested in developing techniques for collecting high-quality time-resolved x-ray scattering data. Herein we present key aspects of the synchrotron beamline and ancillary equipment, including source considerations, rapid (de)compression apparatus, high frequency imaging detectors, and software suitable for processing large volumes of data. A number of examples are presented, including fast equation of state measurements, compression rate dependent synthesis of metastable states in silicon and germanium, and ultrahigh compression rates using a piezoelectric driven diamond anvil cell.

  5. Determining the melting curves of NiSi using the laser-heated diamond anvil cell and the multi-anvil press

    NASA Astrophysics Data System (ADS)

    Wann, E.; Lord, O. T.; Dobson, D. P.; Hunt, S. A.; Wood, I. G.; Vocadlo, L.; Ahmed, J.; Walker, A. M.; Santangeli, J. R.; Walter, M. J.

    2012-12-01

    It is believed that the cores of terrestrial planets consist primarily of an iron-nickel alloy with a small fraction of light elements1. In the case of the Earth, the possible candidates for the light elements are constrained by cosmochemical arguments2. However, although the exact nature of the light element is in dispute, it is widely believed that Si is a significant light element in the core3. Research into the iron-nickel-silicon ternary system is therefore invaluable for our understanding of the composition of the Earth's core and of planetary cores in general. We have initially focused on the FeSi and NiSi end-members as a first step in understanding the ternary system. Recent work on NiSi4,5 has revealed a more complicated phase diagram than that of FeSi, with a range of stable phases found at high pressure and temperature. In order to constrain the liquidus of NiSi, we have carried out experiments in the laser-heated diamond anvil cell (LHDAC) using perturbations in the power versus temperature function as the melting criterion6. Thus far we have determined the melting curve of the room-pressure MnP structured phase to ~20 GPa, which agrees closely with an in situ multi-anvil press experiment in which the melting criteria were 1) the appearance of diffuse scattering during X-ray diffraction and 2) the appearance of convection during X-ray videography. We have also detected the break-in-slope of the melting curve associated with the MnP+ɛ-FeSi+liquid triple point, and extended the melting curve of the ɛ-FeSi structure of NiSi to 50 GPa. We are currently undertaking further experimental work to extend the melting curve above 100 GPa, beyond the pressure at which the CsCl structure becomes the liquid phase. Previous studies indicate that the CsCl structure is likely stable to inner core conditions4,5 making the results of relevance to planetary cores including that of the Earth. (1) Birch, F. Journal of Geophysical Research 1952, 57, 227. (2) Poirier, J. P

  6. High-pressure studies with x-rays using diamond anvil cells

    SciTech Connect

    Shen, Guoyin; Mao, Ho Kwang

    2016-11-22

    Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

  7. High-pressure studies with x-rays using diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Shen, Guoyin; Mao, Ho Kwang

    2017-01-01

    Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials’ properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

  8. Aqueous Chemistry in the Diamond Anvil Cell up to and Beyond the Critical Point of Water

    SciTech Connect

    Bassett, William A.; Chou, I-Ming; Anderson, Alan J.; Mayanovic, Robert

    2008-08-28

    The hydrothermal diamond anvil cell (HDAC) has been developed for the study of fluids and their interactions with other phases. It is capable of pressures up to 10 GPa and temperatures from -190 C to 1200 C. It has found application in studies of equations of state of fluids, reactions between fluids and solids as well as fluids and melts, hydration and dehydration of hydrous solids under P{sub H2O}, fractionation of species between fluids and solids as well as fluids and melts, the effect of P{sub H2O} on melting of silicates, structures of ions and clathrates in solution, preservation of hosts of fluid inclusions at high temperatures, and reactions in clathrates and other organic materials. Visual, spectroscopic, and X-ray methods are used to analyze samples by taking advantage of the exceptional transparency of the diamond anvils. Examples of successful apphcations of the HDAC include the equation of state (EOS) of water, stability of the various stages of hydration of montmorillonite and calcium carbonate, leaching of elements from zircon, the effect of P{sub H2O} on the melting of albite, speciation and structures of Sc, Fe, Cu, Zn, Y, La, Yb, and Br in solution, stability of methane hydrates and Ca(OH){sub 2}, identifying a new H{sub 2}O ice form and sll of methane hydrate. The description of diamond cell configuration, analytical methods, and examples of applications provide evidence of the utility of the technique for many studies of fluids at temperatures and pressures up to and beyond the critical point of water.

  9. High-pressure studies with x-rays using diamond anvil cells.

    PubMed

    Shen, Guoyin; Mao, Ho Kwang

    2017-01-01

    Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

  10. Modeling and simulating of V-shaped piezoelectric micro-cantilevers using MCS theory considering the various surface geometries

    NASA Astrophysics Data System (ADS)

    Korayem, A. H.; Kianfar, A.; Korayem, M. H.

    2016-10-01

    Atomic force microscopy (AFM) is widely used as a tool in studying surfaces and mechanical properties of materials at nanoscale. This paper deals with mechanical and vibration analysis of AFM vibration in the non-contact and tapping modes for V-shaped piezoelectric micro-cantilever (MC) with geometric discontinuities and cross section variation in the air ambient. In the vibration analysis, Euler-Bernoulli beam theory based on modified couple stress (MCS) theory has been used. The governing equation of motion has been derived by using Hamilton's principle. By adopting finite element method (FEM), the MC differential equation has been solved. Damping matrix was considered in the modal space. Frequency response was obtained by using Laplace transform, and it has been compared with experimental results. Newmark algorithm has been used based on constant average acceleration to analyze time response of MC, and then time response results in the vibration mode, far from the sample surface have been compared with experimental data. In vicinity of sample surface, MC is influenced by various nonlinear forces between the probe tip and sample surface, including van der Waals, contact, and capillary forces. Time response was examined at different distances between MC base and sample surface, and the best distance was selected for topography. Topography results of different types of roughness showed that piezoelectric MC has been improved in the air ambient. Topography showed more accurate forms of roughness, when MC passes through sample surface at higher frequencies. The surface topography investigation for tapping and non-contact modes showed that using of these two modes are suitable for topography.

  11. Co-Occurrence of Health Conditions during Childhood: Longitudinal Findings from the UK Millennium Cohort Study (MCS)

    PubMed Central

    Law, Catherine; Bedford, Helen; Hope, Steven

    2016-01-01

    Aims To identify patterns of stability and change in co-occurrence in children between 5–11 years, and to assess if they vary by socio-demographic factors. Methods Data from 9548 singleton children from the UK Millennium Cohort Study (MCS) were assessed for co-occurrence of five common adverse conditions: wheeze; longstanding illness; unfavorable weight; injury; and socio-emotional difficulties. We summed adverse conditions (0–5) for each child at ages 5, 7, and 11 and identified co-occurrence (≥2 conditions). Using multinomial regression, we explored associations between co-occurrence trajectories and child’s sex and ethnicity, maternal education, and income quintile. Results 45.6% of children experienced co-occurrence between 5–11 years (7% experienced constant co-occurrence). More children moved into co-occurrence than moved out (16.9 vs. 11.9%). Mutually-adjusted relative risk ratios (aRRR) showed a gradient by maternal education: compared to children with no co-occurrence whose mothers had a higher/degree, children whose mothers had no qualifications were more likely to move into (aRRR = 1.32(95%CI:1.02,1.70)), out of (1.74(1.34,2.26)), have fluctuating (1.52(1.09,2.10)) or constant co-occurrence (2.58(1.76,3.80)). The same gradient (high vs. low) was evident for income quintiles. Girls were less likely to experience co-occurrence. Conclusions Co-occurrence of adverse conditions is common during childhood, and trajectories are socially patterned. Child-focused care for lower-income children and boys early in life may prevent and reduce co-occurrence in later childhood. PMID:27281228

  12. Examination of physical processes of convective cell evolved from a MCS — Using a different model initialization

    NASA Astrophysics Data System (ADS)

    Spiridonov, Vlado; Ćurić, Mladjen

    2016-06-01

    The present study is focused on examination of the physical processes of convective cell evolved from a MCS occurred on 4 November 2011 over Genoa, Italy. The Quantitative Precipitation Forecasts (QPF) have been performed using WRF v3.6 model under different configurations and cloud permitting simulations. The results indicate underestimation of the amount of precipitation and spatial displacement of the area with a peak 24-h accumulated rainfall in (mm). Our main objective in the research is to test the cloud model ability and performance in simulation of this particular case. For that purpose a set of sensitivity experiments under different model initializations and initial data have been conducted. The results also indicate that the merging process apparently alters the physical processes through low- and middle-level forcing, increasing cloud depth, and enhancing convection. The examination of the microphysical process simulated by the model indicates that dominant production terms are the accretion of rain by graupel and snow, probabilistic freezing of rain to form graupel and dry and wet growth of graupel. Experiment under WRF v3.6 model initialization has shown some advantage in simulation of the physical processes responsible for production and initiation of heavy rainfall compared to other model runs. Most of the precipitation came from ice-phase particles-via accretion processes and the graupel melting at temperature T0 ≥ 0°C. The rainfall intensity and accumulated rainfall calculated by the model closely reflect the amount of rainfall recorded. Thus, the main benefit is to better resolve convective showers or storms which, in extreme cases, can give rise to major flooding events. In such a way, this model may become major contributor to improvements in weather analysis and small-scale atmospheric predictions and early warnings of such subscale processes.

  13. The 2015 Middle Childhood Survey (MCS) of mental health and well-being at age 11 years in an Australian population cohort.

    PubMed

    Laurens, Kristin R; Tzoumakis, Stacy; Dean, Kimberlie; Brinkman, Sally A; Bore, Miles; Lenroot, Rhoshel K; Smith, Maxwell; Holbrook, Allyson; Robinson, Kim M; Stevens, Robert; Harris, Felicity; Carr, Vaughan J; Green, Melissa J

    2017-06-23

    The Middle Childhood Survey (MCS) was designed as a computerised self-report assessment of children's mental health and well-being at approximately 11 years of age, conducted with a population cohort of 87 026 children being studied longitudinally within the New South Wales (NSW) Child Development Study. School Principals provided written consent for teachers to administer the MCS in class to year 6 students at 829 NSW schools (35.0% of eligible schools). Parent or child opt-outs from participation were received for 4.3% of children, and MCS data obtained from 27 808 children (mean age 11.5 years, SD 0.5; 49.5% female), representing 85.9% of students at participating schools. Demographic characteristics of participating schools and children are representative of the NSW population. Children completed items measuring Social Integration, Prosocial Behaviour, Peer Relationship Problems, Supportive Relationships (at Home, School and in the Community), Empathy, Emotional Symptoms, Conduct Problems, Aggression, Attention, Inhibitory Control, Hyperactivity-Inattention, Total Difficulties (internalising and externalising psychopathology), Perceptual Sensitivity, Psychotic-Like Experiences, Personality, Self-esteem, Daytime Sleepiness and Connection to Nature. Distributions of responses on each item and construct demarcate competencies and vulnerabilities within the population: most children report mental health and well-being, but the population distribution spanned the full range of possible scores on every construct. Multiagency, intergenerational linkage of the MCS data with health, education, child protection, justice and early childhood development records took place late in 2016. Linked data were used to elucidate patterns of risk and protection across early and middle child development, and these data will provide a foundation for future record linkages in the cohort that will track mental and physical health, social and educational/occupational outcomes into

  14. INJURY INCIDENCE, DANCE EXPOSURE AND THE USE OF THE MOVEMENT COMPETENCY SCREEN (MCS) TO IDENTIFY VARIABLES ASSOCIATED WITH INJURY IN FULL-TIME PRE-PROFESSIONAL DANCERS.

    PubMed

    Lee, Linda; Reid, Duncan; Cadwell, Jill; Palmer, Priya

    2017-06-01

    Prospective studies utilizing standardized injury and exposure measures are needed to consolidate our knowledge of injury incidence and associated risk factors for musculoskeletal injury amongst pre-professional dancers. The purpose of this study was to investigate the injury incidence amongst pre-professional dancers attending a fulltime training school in New Zealand. The secondary purposes of this study were to investigate the relationship between dance exposure and injury risk, and the relationship between risk factors (specifically the MCS outcome scores) and injury risk. A prospective cohort study of 66 full-time pre-professional dancers was undertaken over one full academic year (38 weeks), included 40 females (mean age 17.78 yrs, SD 1.18) and 26 males (mean age 18.57yrs, SD 1.72). Injury surveillance included both reported and self reported injury data. Dancers were screened using the MCS in the first week of term one. Eighty-six per cent of dancers sustained one or more injuries. Fifty-nine per cent of all injuries were time-loss. The injury incidence rate was 2.27 per 1000 hours of dance exposure (DEhr) and 3.35 per 1000 dance exposures (DE). There was a significant association between the total number of injuries and total DE per month (B=0.003, 95% CI 0.001 - 0.006, p=0.016). Dancers who had a MCS score < 23 were more likely to be injured than those who scored ≥23 (B = -0.702, 95% CI = -1.354 - -0.050, p=0.035). Injury prevalence and incidence was comparable with other international cohorts. The number of dance exposures was more highly associated with injury risk than the hours of dance exposure. The MCS may be a useful tool to help identify dancers at risk of injury. Level 3b, Prospective Longitudinal Cohort Study.

  15. INJURY INCIDENCE, DANCE EXPOSURE AND THE USE OF THE MOVEMENT COMPETENCY SCREEN (MCS) TO IDENTIFY VARIABLES ASSOCIATED WITH INJURY IN FULL-TIME PRE-PROFESSIONAL DANCERS

    PubMed Central

    Reid, Duncan; Cadwell, Jill; Palmer, Priya

    2017-01-01

    Background/Purposes Prospective studies utilizing standardized injury and exposure measures are needed to consolidate our knowledge of injury incidence and associated risk factors for musculoskeletal injury amongst pre-professional dancers. The purpose of this study was to investigate the injury incidence amongst pre-professional dancers attending a fulltime training school in New Zealand. The secondary purposes of this study were to investigate the relationship between dance exposure and injury risk, and the relationship between risk factors (specifically the MCS outcome scores) and injury risk. Methods A prospective cohort study of 66 full-time pre-professional dancers was undertaken over one full academic year (38 weeks), included 40 females (mean age 17.78 yrs, SD 1.18) and 26 males (mean age 18.57yrs, SD 1.72). Injury surveillance included both reported and self reported injury data. Dancers were screened using the MCS in the first week of term one. Results Eighty-six per cent of dancers sustained one or more injuries. Fifty-nine per cent of all injuries were time-loss. The injury incidence rate was 2.27 per 1000 hours of dance exposure (DEhr) and 3.35 per 1000 dance exposures (DE). There was a significant association between the total number of injuries and total DE per month (B=0.003, 95% CI 0.001 - 0.006, p=0.016). Dancers who had a MCS score < 23 were more likely to be injured than those who scored ≥23 (B = -0.702, 95% CI = -1.354 – -0.050, p=0.035). Conclusion Injury prevalence and incidence was comparable with other international cohorts. The number of dance exposures was more highly associated with injury risk than the hours of dance exposure. The MCS may be a useful tool to help identify dancers at risk of injury. Level of Evidence Level 3b, Prospective Longitudinal Cohort Study PMID:28593089

  16. The relation of the yield stress of high-pressure anvils to the pressure attained at yielding and the ultimate attainable pressure

    NASA Technical Reports Server (NTRS)

    Panda, P. C.; Ruoff, A. L.

    1979-01-01

    A sensitive microprofilometer was used to determine the onset of yielding in the anvils of a supported opposed anvil device for the case of 3% cobalt-cemented tungsten carbide as the anvil material. In addition, it is shown how the commencement of yielding in boron carbide pistons, the yield strength being known, can be used to obtain the transition pressure to a conducting phase in gallium phosphide. The transition pressures of bismuth and gallium phosphide are obtained and it is found that these transitions are extremely close to the maximum attainable pressure in, respectively, a maraging steel and a 3% cobalt-cemented tungsten carbide.

  17. OPERATIONS ANVIL, CRESSET, TINDERBOX and GUARDIAN Events Husky Pup, Mighty Epic, Hybla Gold, Diablo Hawk, Huron King, and Miners Iron, 24 October 1975 - 31 October 1980

    DTIC Science & Technology

    1989-04-30

    dtd 19 Jun 2013 HAROLD I_. BRODE DNA 6325F OPERATIONS ANVIL, CRESSET, TINDERBOX, AND GUARDIAN EVENTS HUSKY PUP, MIGHTY EPIC, HYBLA GOLD, DIABLO ...ELEMENT NO WO NO ACCESSION ‘~0 1 1 TITLE (/nc/ude Securrfy c~aSSlf!cJrlOn) OPk3ATIONS ANVIL, CRESSET, TINDERBOX, AND GUARDIAN : Events Ilusky Pup, Mighty...OPERATIONS ANVIL,, CRESSl:T, TINDERBOX, <ind GUARDIAN : Events llusky PUP, Mighty Epic, Ifybla Cold, Di,iblo Il;lwk, lluron King, and Miners Iron, 24 October

  18. The implications of non-linear biological oscillations on human electrophysiology for electrohypersensitivity (EHS) and multiple chemical sensitivity (MCS).

    PubMed

    Sage, Cindy

    2015-01-01

    maintenance; and resilience can be compromised. Electrohypersensitivity can be caused by successive assaults on human bioelectrochemical dynamics from exogenous electromagnetic fields (EMF) and RFR or a single acute exposure. Once sensitized, further exposures are widely reported to cause reactivity to lower and lower intensities of EMF/RFR, at which point thousand-fold lower levels can cause adverse health impacts to the electrosensitive person. Electrohypersensitivity (EHS) can be a precursor to, or linked with, multiple chemical sensitivity (MCS) based on reports of individuals who first develop one condition, then rapidly develop the other. Similarity of chemical biomarkers is seen in both conditions [histamines, markers of oxidative stress, auto-antibodies, heat shock protein (HSP), melatonin markers and leakage of the blood-brain barrier]. Low intensity pulsed microwave activation of voltage-gated calcium channels (VGCCs) is postulated as a mechanism of action for non-thermal health effects.

  19. Studying the effects of POs and MCs on the Salmonella ALOP with a quantitative risk assessment model for beef production.

    PubMed

    Tuominen, Pirkko; Ranta, Jukka; Maijala, Riitta

    2007-08-15

    The Finnish Salmonella Control Programme and the special guarantees (SG) of import concerning Salmonella in the beef production chain were examined within the risk analysis framework. The appropriate level of protection (ALOP de facto since not referred to as ALOP in regulation), performance objectives (PO), and microbiological criteria (MC) were identified along the beef production chain. A quantitative microbiological risk assessment (QMRA) model using the Bayesian probabilistic method was developed for the beef chain to evaluate the capability of different POs to contribute to the ALOP. The influence of SGs was studied as an intervention protecting Finnish consumers. The QMRA made it possible to translate an ALOP without a stated food safety objective (FSO) to POs when implemented for both ready-to-eat (RTE) and non-RTE products. According to the results, the Finnish ALOP de facto for beef, beef preparations and products (10 human Salmonella cases/100,000) was reached in all of the years 1996-2004. However, if the prevalence at the slaughter, domestic cut beef, and retail levels would increase to the level of POs set (maximum 1%), the ALOP de facto would be exceeded by a factor of roughly two. On the other hand, the zero tolerance applied to MCs would keep the true Salmonella prevalence at production steps with POs clearly below 1%, and the ALOP would then be achievable. The influence of SGs on the total exposure was so small (average 0.1% added to the total prevalence of beef-derived foods at retail) that their relevance may be doubted with the current amount and Salmonella prevalence in beef-derived imports. On the other hand, a change in import profile could increase the protective effect of the SGs. Although practical follow-up has to be carried out as apparent prevalences, the objectives and criteria should be estimated as true prevalences and incidences with quantified uncertainties in order to achieve a sound, transparent scientific-based understanding of

  20. Numerical and Observational Investigations of Long-Lived Mcs-Induced Severe Surface Wind Events: the Derecho

    NASA Astrophysics Data System (ADS)

    Schmidt, Jerome Michael

    This study addresses the production of sustained, straight-line, severe surface winds associated with mesoscale convective systems (MCSs) of extratropical origin otherwise known as derechos. The physical processes which govern the observed derecho characteristics are identified and their possible forcing mechanisms are determined. Detailed observations of two derechos are presented along with simulations using the Colorado State University Regional Atmospheric Modeling System (CSU-RAMS). The observations revealed a derecho environment characterized by strong vertical wind shear through the depth of the troposphere and large values of convective available potential energy (CAPE). The thermodynamic environment of the troposphere in each case had a distinct three-layer structure consisting of: (i) a surface-based stable layer of 1-to-2 km in depth, (ii) an elevated well -mixed layer of 2-4 km in depth, and (iii) an upper tropospheric layer of intermediate stability that extended to the tropopause. Two primary sets of simulations were performed to assess the impact of the observed environmental profiles on the derecho structure, propagation, and longevity. The first set consisted of nested-grid regional-scale simulations initialized from the standard NMC analyses on a domain having relatively coarse horizontal resolution (75 km). The second set of simulations consisted of two and three-dimensional experiments initialized in a horizontally homogeneous environment having a relatively fine horizontal resolution (2 km) and explicit microphysics. The results from these experiments indicate the importance of convectively -induced gravity waves on the MCS structure, propagation, longevity, and severe surface wind development. The sensitivity of the simulated convection and gravity waves to variations in the vertical wind shear and moisture profiles are described. Detailed Doppler radar analyses and 3-D simulations of a severe, bow echo squall line are presented which reveal

  1. Multi-Anvil Techniques in Conjunction With Synchrotron Radiation - MAX80 and MAX200x

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Schilling, F. R.; Lathe, C.

    2005-12-01

    During the early 80's of the last century geoscientists worldwide realized synchrotron radiation as a highly valuable tool for in situ experiments, i.e. experiments under simulated Earth's mantle conditions. MAX80 at HASYLAB, Hamburg, a single-stage multi-anvil DIA-system at a synchrotron beamline was among the high-pressure pioneer apparatus designed in Japan. Meantime it is equipped for all kinds of ultrasonic interferometry in conjunction with synchrotron radiation measurements, i.e. XRD and X-radiography. The maximum conditions are about 10 GPa / 2000 K. To make transition zone conditions accessible and to achieve bigger specimen volumes the sister apparatus MAX200x, a double-stage DIA-system, was installed at the HASYLAB HARWI-II beamline recently. The newly designed high-flux hard wiggler is an optimum X-ray source for this kind of experiments. MAX2000x is designed to reach 25 GPa and 2400 K, simultaneously. MAX200x is driven by a hydraulic ram with a maximum load of 1750 tons. This press is mounted on a y-z-table to adjust the sample to the synchrotron beam. Furthermore, the press can be rotated to enhance statistics during the diffraction experiments. The whole system weights about 30 tons. Derived from the successful equipment of MAX80 and adapted to the new task MAX200x is equipped for XRD with a Ge-solid-state detector, for transient ultrasonic interferometry, as well as with a radiography system to measure the change of volume and shape of the sample under in situ conditions. A stepper motor driven slits system allows to optimize X-ray beam size and shape for the experiments. The whole system is remote controlled. The goniometer will be mounted on a moveable table. Both, experiments with monochromatic and white X-rays will be available. Besides Ge-solid state detector new designed goniometers will be used to enhance the precision of the experiments. Parallel to the installation of MAX200x some innovative experiments were carried out to improve the

  2. The Stratiform Region of an MCS on 19 June in TELEX 2004 Observed With Polarimetric and Doppler Radars, Electric Field Soundings, and a Lightning Mapping Array

    NASA Astrophysics Data System (ADS)

    Ramig, N.; Macgorman, D.; Rust, D.; Schuur, T.; Bruning, E.; Krehbiel, P.; Rison, W.; Hamlin, T.; Straka, J.; Payne, C.; Apostolakopoulos, I.; Biggerstaff, M. I.; Biermann, N.; Carey, L.

    2005-12-01

    Polarimetric and Doppler radar data, balloon-borne soundings of the electric field, and three-dimensional lightning mapping array data were acquired from a mesoscale convective system (MCS) on 19 June 2004 during the Thunderstorm Electrification and Lightning Experiment (TELEX). A total of 10 partial and complete vertical soundings through the storm were obtained from the flights of four instrumented balloons: two launched in the convective region, one in the transition zone, and one in the stratiform region. Each balloon recorded ascent and descent soundings and the transition zone balloon recorded an additional two partial soundings due to a downdraft. At times, multiple soundings were in progress simultaneously. This study focuses on the stratiform region of the MCS, which was sampled by the last two soundings of balloon three and both soundings of balloon four. A comparison of the electrical structure of the stratiform region of this MCS with that of previously published conceptual models suggests that, during at least part of the MCS's lifetime, its electrical structure was Type A, which is more complex than Type B. The main difference between these classifications is the number of charge regions in the cloud. A one-dimensional analysis with Gauss's law indicates six vertically stacked charge layers that alternated polarity within the stratiform region during balloon four's ascent. The vector electric field pattern verified the 1-D Gauss analysis and showed the electric field structure to be primarily horizontally stratified. The maximum magnitude of the electric field was approximately 105 kV/m. The second stratiform sounding sampled by balloon three began fifty minutes after the first stratiform sounding. It showed a very different electric field profile, consistent with neither Type A nor Type B electrical structure, perhaps because the sounding was far from the front of the MCS. There were only three charge layers as opposed to the four charge layers

  3. The COMPRES/GSECARS gas-loading system for diamond anvil cells at the Advanced Photon Source

    SciTech Connect

    Rivers, Mark; Prakapenka, Vitali B.; Kubo, Atsushi; Pullins, Clayton; Holl, Christopher M.; Jacobsen, Steven D.

    2008-11-18

    We have designed and constructed a new system for loading gases at high pressure into diamond anvil cells at pressures up to 200 MPa. The gases are used either as quasi-hydrostatic pressure media surrounding the sample or as the sample itself. The diamond cell is sealed using a clamping mechanism, which permits nearly any type of diamond anvil cell to be used. Online ruby fluorescence and video imaging systems allow in situ monitoring of the pressure and gasket deformation as the cell is sealed, resulting in a very high success rate in loading cells. The system includes interlocks and computer control that allow it to be safely and easily operated by visiting users at the Advanced Photon Source. We present preliminary X-ray diffraction data on volume compression of single-crystal magnesium oxide (MgO) in helium up to 110 GPa.

  4. Hydrothermal diamond anvil cell for XAFS studies of first-row transition elements in aqueous solutions up to supercritical conditions

    USGS Publications Warehouse

    Bassett, William A.; Anderson, Alan J.; Mayanovic, Robert A.; Chou, I.-Ming

    2000-01-01

    A hydrothermal diamond anvil cell (HDAC) has been modified by drilling holes with a laser to within 150 ??m of the anvil face to minimize the loss of X-rays due to absorption and scatter by diamond. This modification enables acquisition of K-edge X-ray absorption fine structure (XAFS) spectra from first-row transition metal ions in aqueous solutions at temperatures ranging from 25??C to 660??C and pressures up to 800 MPa. These pressure-temperature (P-T) conditions are more than sufficient for carrying out experimental measurements that can provide data valuable in the interpretation of fluid inclusions in minerals found in ore-forming hydrothermal systems as well as other important lithospheric processes involving water. (C) 2000 Elsevier Science B.V. All rights reserved.

  5. InAsP-based quantum wells as infrared pressure gauges for use in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Trushkin, S.; Kamińska, A.; Trzeciakowski, W.; Hopkinson, M.; Suchocki, A.

    2012-10-01

    The results of high-pressure, low-temperature luminescence measurements of three InAsP-based multiple quantum well structures are reported for application as pressure sensors for diamond anvil cells working in the near-infrared spectral range. The multiple quantum well structures exhibit a much higher pressure shift of the luminescence lines as compared with ruby, typically used as the pressure sensor for diamond anvil cell. However, the full width at half maximum of the quantum wells is much higher than that for ruby. This reduces the available sensitivity gain exhibited by the InAsP-based quantum wells, but the improvement is still 2-3 times higher than that of ruby. Three InAsP multiple quantum well samples were examined, which exhibited luminescence at various wavelengths. The wavelength shift of these samples could be calibrated using similar parameters.

  6. Pressure estimation for diamond anvils cell under very-low pressures, hydrostatic conditions -evaluation for quartz Raman peak shifts-

    NASA Astrophysics Data System (ADS)

    Kubo, K.; Okamoto, K.

    2016-12-01

    Pressure shift of the ruby R1 luminescent shift has been used as primary pressure gauge in diamond-anvils experiments. However, the pressure calibration under low-pressure conditions (<1 GPa) was poorly constrained although crustal hydrothermal experiments are important. Therefore in order to calibrate the R1 luminescent shits at low-pressure conditions, we have done diamond anvils experiments at room temperature conditions. H2O was used as pressure transmitting medium and all experimental pressures was below ice stability field in order to keep hydrostatic-pressure conditions. We could get well-constrained calibration line. It is noticeable that the result has a certain discrepancy with quartz Raman-shift pressure gauge reported by Schmidt and Ziemenn (2000). At pressure lower than 1 GPa, their pressure calibration give 0.2 GPa lower conditions than the Ruby pressure gauge at 1 GPa.

  7. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  8. African Pentecostalism

    ERIC Educational Resources Information Center

    Garrard, David J.

    2009-01-01

    The diversity of African Pentecostalism, its early colonial and missionary history and its current characteristics are described and analysed. Reference is made to methods of training and forms of leadership, and suggestions are made about the reasons for its growth and persistence. (Contains 19 notes.)

  9. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  10. Microfabrication of controlled-geometry samples for the laser-heated diamond-anvil cell using focused ion beam technology.

    PubMed

    Pigott, Jeffrey S; Reaman, Daniel M; Panero, Wendy R

    2011-11-01

    The pioneering of x-ray diffraction with in situ laser heating in the diamond-anvil cell has revolutionized the field of high-pressure mineral physics, expanding the ability to determine high-pressure, high-temperature phase boundaries and equations of state. Accurate determination of high-pressure, high-temperature phases and densities in the diamond-anvil cell rely upon collinearity of the x-ray beam with the center of the laser-heated spot. We present the development of microfabricated samples that, by nature of their design, will have the sample of interest in the hottest portion of the sample. We report initial successes with a simplified design using a Pt sample with dimensions smaller than the synchrotron-based x-ray spot such that it is the only part of the sample that absorbs the heating laser ensuring that the x-rayed volume is at the peak hotspot temperature. Microfabricated samples, synthesized using methods developed at The Ohio State University's Mineral Physics Laboratory and Campus Electron Optics Facility, were tested at high P-T conditions in the laser-heated diamond-anvil cell at beamline 16 ID-B of the Advanced Photon Source. Pt layer thicknesses of ≤0.8 μm absorb the laser and produce accurate measurements on the relative equations of state of Pt and PtC. These methods combined with high-purity nanofabrication techniques will allow for extension by the diamond-anvil cell community to multiple materials for high-precision high-pressure, high-temperature phase relations, equations of state, melting curves, and transport properties.

  11. High-pressure high-temperature phase diagram of gadolinium studied using a boron-doped heater anvil

    DOE PAGES

    Montgomery, J. M.; Samudrala, G. K.; Velisavljevic, N.; ...

    2016-04-07

    A boron-doped designer heater anvil is used in conjunction with powder x-ray diffraction to collect structural information on a sample of quasi-hydrostatically loaded gadolinium metal up to pressures above 8 GPa and 600 K. The heater anvil consists of a natural diamond anvil that has been surface modified with a homoepitaxially-grown chemical-vapor-deposited layer of conducting boron-doped diamond, and is used as a DC heating element. Internally insulating both diamond anvils with sapphire support seats allows for heating and cooling of the high pressure area on the order of a few tens of seconds. This device is then used to scanmore » the phase diagram of the sample by oscillating the temperature while continuously increasing the externally applied pressure and collecting in situ time-resolved powder diffraction images. In the pressure-temperature range covered in the experiment the gadolinium sample is observed in its hcp, αSm, and dhcp phases. Under this temperature cycling, the hcp→αSm transition proceeds in discontinuous steps at points along the expected phase boundary. Additionally, the unit cell volumes of each phase deviate from the expected thermal expansion behavior just before each transition is observed from the diffraction data. From these measurements (representing only one hour of synchrotron x-ray collection time), a single-experiment equation of state and phase diagram of each phase of gadolinium is presented for the range of 0 - 10 GPa and 300 - 650 K.« less

  12. Anvil Glaciation in a Deep Cumulus Updraught over Florida Simulated with the Explicit Microphysics Model. I: Impact of Various Nucleation Processes

    NASA Technical Reports Server (NTRS)

    Phillips, Vaughan T. J.; Andronache, Constantin; Sherwood, Steven C.; Bansemer, Aaron; Conant, William C.; Demott, Paul J.; Flagan, Richard C.; Heymsfield, Andy; Jonsson, Haflidi; Poellot, Micheal; Rissman, Tracey A.; Seinfeld, John H.; Vanreken, Tim; Varutbangkul, Varuntida; Wilson, James C.

    2005-01-01

    Simulations of a cumulonimbus cloud observed in the Cirrus regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) with an advanced version of the Explicit Microphysics Model (EMM) are presented. The EMM has size-resolved aerosols and predicts the time evolution of sizes, bulk densities and axial ratios of ice particles. Observations by multiple aircraft in the troposphere provide inputs to the model, including observations of the ice nuclei and of the entire size distribution of condensation nuclei. Homogeneous droplet freezing is found to be the source of almost all of the ice crystals in the anvil updraught of this particular model cloud. Most of the simulated droplets that freeze to form anvil crystals appear to be nucleated by activation of aerosols far above cloud base in the interior of the cloud ("secondary" or "in cloud" droplet nucleation). This is partly because primary droplets formed at cloud base are invariably depleted by accretion before they can reach the anvil base in the updraught, which promotes an increase with height of the average supersaturation in the updraught aloft. More than half of these aerosols, activated far above cloud base, are entrained into the updraught of this model cloud from the lateral environment above about 5 km above mean sea level. This confirms the importance of remote sources of atmospheric aerosol for anvil glaciation. Other nucleation processes impinge indirectly upon the anvil glaciation by modifying the concentration of supercooled droplets in the upper levels of the mixed-phase region. For instance, the warm-rain process produces a massive indirect impact on the anvil crystal concentration, because it determines the mass of precipitation forming in the updraught. It competes with homogeneous freezing as a sink for cloud droplets. The effects from turbulent enhancement of the warm-rain process and from the nucleation processes on the anvil ice properties are assessed.

  13. Anvil Glaciation in a Deep Cumulus Updraught over Florida Simulated with the Explicit Microphysics Model. I: Impact of Various Nucleation Processes

    NASA Technical Reports Server (NTRS)

    Phillips, Vaughan T. J.; Andronache, Constantin; Sherwood, Steven C.; Bansemer, Aaron; Conant, William C.; Demott, Paul J.; Flagan, Richard C.; Heymsfield, Andy; Jonsson, Haflidi; Poellot, Micheal; hide

    2005-01-01

    Simulations of a cumulonimbus cloud observed in the Cirrus regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) with an advanced version of the Explicit Microphysics Model (EMM) are presented. The EMM has size-resolved aerosols and predicts the time evolution of sizes, bulk densities and axial ratios of ice particles. Observations by multiple aircraft in the troposphere provide inputs to the model, including observations of the ice nuclei and of the entire size distribution of condensation nuclei. Homogeneous droplet freezing is found to be the source of almost all of the ice crystals in the anvil updraught of this particular model cloud. Most of the simulated droplets that freeze to form anvil crystals appear to be nucleated by activation of aerosols far above cloud base in the interior of the cloud ("secondary" or "in cloud" droplet nucleation). This is partly because primary droplets formed at cloud base are invariably depleted by accretion before they can reach the anvil base in the updraught, which promotes an increase with height of the average supersaturation in the updraught aloft. More than half of these aerosols, activated far above cloud base, are entrained into the updraught of this model cloud from the lateral environment above about 5 km above mean sea level. This confirms the importance of remote sources of atmospheric aerosol for anvil glaciation. Other nucleation processes impinge indirectly upon the anvil glaciation by modifying the concentration of supercooled droplets in the upper levels of the mixed-phase region. For instance, the warm-rain process produces a massive indirect impact on the anvil crystal concentration, because it determines the mass of precipitation forming in the updraught. It competes with homogeneous freezing as a sink for cloud droplets. The effects from turbulent enhancement of the warm-rain process and from the nucleation processes on the anvil ice properties are assessed.

  14. Calibration of an isotopically enriched carbon-13 layer pressure sensor to 156 GPa in a diamond anvil cell

    SciTech Connect

    Qiu,W.; Baker, P.; Velisavljevic, N.; Vohra, Y.; Weir, S.

    2006-01-01

    An isotopically enriched {sup 13}C homoepitaxial diamond layer of 6{+-}1 {mu}m thickness was grown on top of a brilliant cut diamond anvil by a microwave plasma chemical vapor deposition process for application as a pressure sensor. This isotopically enriched diamond tip was then used in conjunction with a natural isotopic abundance diamond anvil to generate high pressure on the sample. We provide a calibration for the {sup 13}C Raman mode of this extremely thin epitaxial layer to 156 GPa using ruby fluorescence and the equation of state of copper as secondary pressure standards. The nonlinear calibration of the {sup 13}C Raman mode pressure sensor is compared with similar calibrations of {sup 12}C Raman edge and a good agreement is obtained. The Raman signal from the {sup 13}C epitaxial layer remained a distinct singlet to 156 GPa, and pressure calibration is independent of sample mechanical strength or the diamond anvil geometry. The use of even thinner layer would allow calibration further into ultrahigh pressure regime where the use of other optical sensors has proven to be difficult.

  15. Magnetic measurements at pressures above 10 GPa in a miniature ceramic anvil cell for a superconducting quantum interference device magnetometer.

    PubMed

    Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma D; Fisk, Zachary

    2012-05-01

    A miniature ceramic anvil high pressure cell (mCAC) was earlier designed by us for magnetic measurements at pressures up to 7.6 GPa in a commercial superconducting quantum interference magnetometer [N. Tateiwa et al., Rev. Sci. Instrum. 82, 053906 (2011)]. Here, we describe methods to generate pressures above 10 GPa in the mCAC. The efficiency of the pressure generation is sharply improved when the Cu-Be gasket is sufficiently preindented. The maximum pressure for the 0.6 mm culet anvils is 12.6 GPa when the Cu-Be gasket is preindented from the initial thickness of 300-60 μm. The 0.5 mm culet anvils were also tested with a rhenium gasket. The maximum pressure attainable in the mCAC is about 13 GPa. The present cell was used to study YbCu(2)Si(2) which shows a pressure induced transition from the non-magnetic to magnetic phases at 8 GPa. We confirm a ferromagnetic transition from the dc magnetization measurement at high pressure. The mCAC can detect the ferromagnetic ordered state whose spontaneous magnetic moment is smaller than 1 μ(B) per unit cell. The high sensitivity for magnetic measurements in the mCAC may result from the simplicity of cell structure. The present study shows the availability of the mCAC for precise magnetic measurements at pressures above 10 GPa.

  16. Effect of shear stress on the high-pressure behaviour of nitromethane: Raman spectroscopy in a shear diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Hebert, Philippe; Isambert, Aude; Petitet, Jean-Pierre; Zerr, Andreas

    2009-06-01

    A detailed description of the reaction mechanisms occurring in shock-induced decomposition of condensed energetic materials is very important for a comprehensive understanding of detonation. Besides pressure and temperature effects, shear stress has also been proposed to play an important role in the initiation and decomposition mechanisms. In order to study this effect, a Shear Diamond Anvil Cell (SDAC) has been developed. It is actually a classical DAC with the upper diamond anvil rotating about the compression axis relative to the opposite anvil. In this paper, we present a Raman spectroscopy study of the effect of shear stress on the high-pressure behaviour of nitromethane. Two major effects of shear stress are observed in our experiments. The first one is a lowering of the pressures at which the different structural modifications that nitromethane undergoes are observed. The second effect is observed at 28 GPa where sudden decomposition of the sample occurs just after shear application. Observation of the sample after decomposition shows the presence of a black residue which is composed of carbon as indicated by the Raman spectrum. [1] Manaa, M. R., Fried, L. E., and Reed, E. J., Journal of Computer-Aided Materials Design, 10, pp 75-97, 2003.

  17. Wild bearded capuchin (Sapajus libidinosus) select hammer tools on the basis of both stone mass and distance from the anvil.

    PubMed

    Massaro, Luciana; Liu, Qing; Visalberghi, Elisabetta; Fragaszy, Dorothy

    2012-11-01

    Contemporary optimization models suggest that animals optimize benefits of foraging and minimize its costs. For wild bearded capuchins (Sapajus libidinosus), nut-cracking entails cost related to lifting the heavy stone and striking the nut and additional cost to transport the stone if it is not already on the anvil. To assess the role of stone mass and transport distance in capuchins' tool selection, we carried out three field experiments. In Experiment 1, we investigated whether transport distance affected choice of a tool by positioning two stones of the same mass close and far from the anvil. Capuchins consistently selected the closer stone, effectively reducing transport costs. In Experiment 2, we examined the trade-off between the cost of transport and the effectiveness in cracking by positioning two stones of different mass close and far from the anvil. Most subjects significantly preferred the closer stone, regardless of mass, whereas others preferred the heavier stone regardless of transport distance. In Experiment 3, we changed transport distance of both stones while maintaining the same distance ratios as in Experiment 2. Capuchins maintained the preferences expressed in Experiment 2, with the exception of one subject. Overall, our findings indicate that (1) individuals vary in their sensitivity to distance of transport, (2) a few meters are perceived as a substantive cost by some monkeys, and (3) monkeys' body mass affects their decisions. We also developed a non-dimensional Preference index (P) defined as a function of the stone mass and the transport distance to describe monkey's choice.

  18. High Pressure Calibration at High Temperatures in the Diamond Anvil Cell Using Cubic Boron Nitride

    NASA Astrophysics Data System (ADS)

    Goncharov, A. F.; Crowhurst, J. C.

    2006-12-01

    The equation of state (EOS) and pressure dependence of the transverse optical (TO) Raman-active mode of cubic boron nitride (cBN) are proposed for pressure calibration in the diamond anvil cell (DAC) at high temperatures. We determined the EOS and the pressure dependence of the TO mode of cBN in the laser heated DAC up to 70 GPa and 3300 K, and cross-checked the results with ambient pressure data, theoretical density functional calculations, and empirical relations. Moreover, the thermal EOS of Ir determined in the course of the same experiment was found to be similarly consistent. The proposed high temperature pressure scale may be further improved on the basis of simultaneous measurements of density and sound velocities at high P-T conditions, which would provide an independent pressure determination. This study is in progress and will be reported at the Meeting. We thank John K. Dewhurst, Sangeeta Sharma, Chrystele Sanloup, Eugene Gregoryanz for their contribution to this study. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and we would like to thank Nicola Guignot and Mohamed Mezour for assistance with the XRD measurements.

  19. Hydrothermal diamond-anvil cell: Application to studies of geologic fluids

    USGS Publications Warehouse

    Chou, I.-Ming

    2003-01-01

    The hydrothermal diamond-anvil cell (HDAC) was designed to simulate the geologic conditions of crustal processes in the presence of water or other fluids. The HDAC has been used to apply external pressure to both synthetic and natural fluid inclusions in quartz to minimize problems caused by stretching or decrepitation of inclusions during microthermometric analysis. When the HDAC is loaded with a fluid sample, it can be considered as a large synthetic fluid inclusion and therefore, can be used to study the PVTX properties as well as phase relations of the sample fluid. Because the HDAC has a wide measurement pressure-temperature range and also allows in-situ optical observations, it has been used to study critical phenomena of various chemical systems, such as the geologically important hydrous silicate melts. It is possible, when the HDAC is combined with synchrotron X-ray sources, to obtain basic information on speciation and structure of metal including rare-earth elements (REE) complexes in hydrothermal solutions as revealed by X-ray absorption fine structure (XAFS) spectra. Recent modifications of the HDAC minimize the loss of intensity of X-rays due to scattering and absorption by the diamonds. These modifications are especially important for studying elements with absorption edges below 10 keV and therefore particularly valuable for our understanding of transport and deposition of first-row transition elements and REE in hydrothermal environments.

  20. Kinetic study of phase transformation of n-octane using hydrothermal diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Liu, Chuanjiang; Zheng, Haifei; Wang, Duojun

    2016-02-01

    A kinetic study of phase transformation of n-octane has been performed using a hydrothermal diamond anvil cell. The results show that pressure has a negative effect on the solid-liquid reaction rate. The increase of pressure can accelerate the liquid-solid transformation rate. Upon the liquid-solid transformation, the light transmittance showed a decreased trend with time in the early stage, which was caused by the formation of a large quantity of crystal nuclei. In the later stage, the light transmittance almost remained the same, thus indicating a growth stage of crystal nuclei. The activation volume yields a value of 2.16×10-5 and -1.35×10-5 m3/mol for the solid-liquid and liquid-solid transformations. Based on the obtained activation energy, the solid-liquid transformation is dominated by the interfacial reaction and diffusion, and the liquid-solid transformation is controlled by diffusion. This technique is an effective and powerful tool for the transformation kinetics study of n-octane.

  1. Four-probe electrical measurements with a liquid pressure medium in a diamond anvil cell.

    PubMed

    Jaramillo, R; Feng, Yejun; Rosenbaum, T F

    2012-10-01

    We describe a technique for making electrical transport measurements in a diamond anvil cell using an alcohol pressure medium, permitting acute sensitivity while preserving sample fidelity. The sample is suspended in the liquid medium by four gold leads that are electrically isolated by a composite gasket made of stainless steel and an alumina-loaded epoxy. We demonstrate the technique with four-probe resistivity measurements of chromium single crystals at temperatures down to 4 K and pressures above 10 GPa. Our assembly is optimized for making high precision measurements of the magnetic phase diagram and quantum critical regime of chromium, which require repeated temperature sweeps and fine pressure steps while maintaining high sample quality. The high sample quality enabled by the quasi-hydrostatic pressure medium is evidenced by the residual resistivity below 0.1 μΩ cm and the relative resistivity ratio ρ(120 K)/ρ(5 K) = 15.9 at 11.4 GPa. By studying the quality of Cr's antiferromagnetic transition over a range of pressures, we show that the pressure inhomogeneity experienced by the sample is always below 5%. Finally, we solve for the Debye temperature of Cr up to 11.4 GPa using the Bloch-Gruneisen formula and find it to be independent of pressure.

  2. Evaluations of pressure-transmitting media for cryogenic experiments with diamond anvil cell.

    PubMed

    Tateiwa, Naoyuki; Haga, Yoshinori

    2009-12-01

    The fourteen kinds of pressure-transmitting media were evaluated by the ruby fluorescence method at room temperature, 77 K using the diamond anvil cell (DAC) up to 10 GPa in order to find appropriate media for use in low temperature physics. The investigated media are a 1:1 mixture by volume of Fluorinert FC-70 and FC-77, Daphne 7373 and 7474, NaCl, silicon oil (polydimethylsiloxane), Vaseline, 2-propanol, glycerin, a 1:1 mixture by volume of n-pentane and isopentane, a 4:1 mixture by volume of methanol and ethanol, petroleum ether, nitrogen, argon, and helium. The nonhydrostaticity of the pressure is discussed from the viewpoint of the broadening effect of the ruby R(1) fluorescence line. The R(1) line basically broadens above the liquid-solid transition pressure at room temperature. However, the nonhydrostatic effects do constantly develop in all the media from the low-pressure region at low temperature. The relative strength of the nonhydrostatic effects in the media at the low temperature region is discussed. The broadening effect of the ruby R(1) line in the nitrogen, argon, and helium media are significantly small at 77 K, suggesting that the media are more appropriate for cryogenic experiments under high pressure up to 10 GPa with the DAC. The availability of the three media was also confirmed at 4.2 K.

  3. Online remote control systems for static and dynamic compression and decompression using diamond anvil cells.

    PubMed

    Sinogeikin, Stanislav V; Smith, Jesse S; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

    2015-07-01

    The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research.

  4. Online remote control systems for static and dynamic compression and decompression using diamond anvil cells

    SciTech Connect

    Sinogeikin, Stanislav V. Smith, Jesse S.; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

    2015-07-15

    The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research.

  5. A Thermal-Stress Model of a High Pressure Diamond-Anvil Cell

    NASA Astrophysics Data System (ADS)

    Ladouceur, H. D.; Pangilinan, G. I.; Russell, T. P.

    2000-03-01

    A time-dependent mathematical model to describe both thermal and stress propagation in a material compressed to high pressures in a diamond-anvil cell has been formulated. The cell is treated as an axisymmetric composite solid with temperature-dependent thermal conductivity. The effects of various boundary conditions on the interior temperature have been modeled and investigated. A finite-element code (FlexPDE) is utilized to solve the heat-conduction equation and the associated stress propagation equations. The model is utilized to interpret recent experiments* that investigate the transport of thermal and elastic waves in compressed media. The mathematical analysis and experimental data reveal that both thermal and stress propagation simultaneously occurs over two distinct time scales. The thermal propagation model utilizes the familiar parabolic heat-conduction equation, which implies that the effects of the thermal disturbance are instantaneously felt throughout the computational domain. The validity of the parabolic heat-conduction model is examined and compared with available experimental data. A one-dimensional transient analytic approximation for the temperature is also discussed. * Ladouceur, et.al., 1999 AIRAPT Proc.

  6. X-ray diffraction in the pulsed laser heated diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen

    2010-11-01

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 μs pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10 000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 μm thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  7. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    SciTech Connect

    Meier, Thomas; Haase, Jürgen

    2015-12-15

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al{sub 2}O{sub 3}), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  8. Diamond-anvil high-pressure cell with improved X-ray collimation system

    DOEpatents

    Schiferl, David; Olinger, Barton W.; Livingston, Robert W.

    1986-01-01

    An adjustable X-ray collimation system for a diamond-anvil high-pressure cell of the type including a cooperable piston and cylinder and a pair of opposing diamonds located between the head of the piston and the head of the cylinder. The X-ray collimation system includes a tubular insert which contains an X-ray collimator. The insert is engageable in the bore of the piston. The collimator is mounted within the insert by means of an elastomeric O-ring at the end closest the opposed diamonds, and by means of a set of adjustable set screws at the opposite end. By adjustment of the set screws the collimator can be pivoted about the O-ring and brought into alignment with the opposed diamonds and the sample contained therein. In the preferred embodiment there is further provided a set of plugs which are insertable in the bore of the collimator. The plugs have bores of different diameters. By successively inserting plugs of progressively smaller bore diameters and adjusting the alignment of the collimator with each plug, the collimator can be quickly brought into accurate alignment with the diamonds. The collimation system allows alignment of the collimator either before or after the cell has been loaded and pressurized.

  9. Diamond-anvil high-pressure cell with improved x-ray collimation system

    DOEpatents

    Schiferl, D.; Olinger, B.W.; Livingston, R.W.

    1984-03-30

    An adjustable x-ray collimation system for a diamond-anvil high-pressure cell of the type including a cooperable piston and cylinder and a pair of opposing diamonds located between the head of the piston and the head of the cylinder. The x-ray collimation system includes a tubular insert which contains an x-ray collimator. The insert is engageable in the bore of the piston. The collimator is mounted within the insert by means of an elastomeric o-ring at the end closest the opposed diamonds, and by means of a set of adjustable set screws at the opposite end. By adjustment of the set screws the collimator can be pivoted about the o-ring and brought into alignment with the opposed diamonds and the sample contained therein. In the preferred embodiment there is further provided a set of plugs which are insertable in the bore of the collimator. The plugs have bores of different diameters. By successively inserting plugs of progressively smaller bore diameters and adjusting the alignment of the collimator with each plug, the collimator can be quickly brought into accurate alignment with the diamonds. The collimation system allows alignment of the collimator either before or after the cell has been loaded and pressurized.

  10. Single Crystal Preparation for High-Pressure Experiments in the Diamond Anvil Cell

    SciTech Connect

    Aracne, C; Farber, D; Benterou, J; Occelli, F; Krisch, M; Antonangeli, D; Requardt, H; Fiquet, G

    2003-07-01

    Most research conducted in diamond anvil cells (DAC) is performed on polycrystalline samples. While data from polycrystalline samples are sufficient for determining the bulk properties, high-pressure experiments on single crystals allow for measurements on a range of tensor properties such as: thermal and electrical conductivity; magnetic susceptibility; elasticity; and plasticity. However, in order to achieve pressures above 1 Mbar in a DAC, single crystal samples must be <50 m in diameter and <15 m thick while maintaining a high degree of crystallinity. Thus, we have developed new procedures for producing extremely high-quality micro single crystal samples from commercially available material. Our sample preparation steps include cutting, classical metallographic polishing, and laser ablation. The key to our new process is the preservation of crystallinity during cutting and thinning. We have been successful in maintaining orientation, along with an extremely high degree of crystallinity in completed metal samples. To date, we have analyzed cobalt and molybdenum samples with both white-light interferometry and synchrotron x-ray diffraction, and are in the process of extending these methods to other metals and ceramics.

  11. Evaluations of pressure-transmitting media for cryogenic experiments with diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Tateiwa, Naoyuki; Haga, Yoshinori

    2009-12-01

    The fourteen kinds of pressure-transmitting media were evaluated by the ruby fluorescence method at room temperature, 77 K using the diamond anvil cell (DAC) up to 10 GPa in order to find appropriate media for use in low temperature physics. The investigated media are a 1:1 mixture by volume of Fluorinert FC-70 and FC-77, Daphne 7373 and 7474, NaCl, silicon oil (polydimethylsiloxane), Vaseline, 2-propanol, glycerin, a 1:1 mixture by volume of n-pentane and isopentane, a 4:1 mixture by volume of methanol and ethanol, petroleum ether, nitrogen, argon, and helium. The nonhydrostaticity of the pressure is discussed from the viewpoint of the broadening effect of the ruby R1 fluorescence line. The R1 line basically broadens above the liquid-solid transition pressure at room temperature. However, the nonhydrostatic effects do constantly develop in all the media from the low-pressure region at low temperature. The relative strength of the nonhydrostatic effects in the media at the low temperature region is discussed. The broadening effect of the ruby R1 line in the nitrogen, argon, and helium media are significantly small at 77 K, suggesting that the media are more appropriate for cryogenic experiments under high pressure up to 10 GPa with the DAC. The availability of the three media was also confirmed at 4.2 K.

  12. Combined laser ultrasonics, laser heating, and Raman scattering in diamond anvil cell system

    NASA Astrophysics Data System (ADS)

    Zinin, Pavel V.; Prakapenka, Vitali B.; Burgess, Katherine; Odake, Shoko; Chigarev, Nikolay; Sharma, Shiv K.

    2016-12-01

    We developed a multi-functional in situ measurement system under high pressure equipped with a laser ultrasonics (LU) system, Raman device, and laser heating system (LU-LH) in a diamond anvil cell (DAC). The system consists of four components: (1) a LU-DAC system (probe and pump lasers, photodetector, and oscilloscope) and DAC; (2) a fiber laser, which is designed to allow precise control of the total power in the range from 2 to 100 W by changing the diode current, for heating samples; (3) a spectrometer for measuring the temperature of the sample (using black body radiation), fluorescence spectrum (spectrum of the ruby for pressure measurement), and Raman scattering measurements inside a DAC under high pressure and high temperature (HPHT) conditions; and (4) an optical system to focus laser beams on the sample and image it in the DAC. The system is unique and allows us to do the following: (a) measure the shear and longitudinal velocities of non-transparent materials under HPHT; (b) measure temperature in a DAC under HPHT conditions using Planck's law; (c) measure pressure in a DAC using a Raman signal; and (d) measure acoustical properties of small flat specimens removed from the DAC after HPHT treatment. In this report, we demonstrate that the LU-LH-DAC system allows measurements of velocities of the skimming waves in iron at 2580 K and 22 GPa.

  13. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa.

    PubMed

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  14. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    NASA Astrophysics Data System (ADS)

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  15. Observations of Mammatus from a Deep Convective Anvil over the ARM Climate Research Facility

    NASA Astrophysics Data System (ADS)

    Giangrande, S. E.; Jensen, M. P.; Straka, J.; Kollias, P.; Johnson, K. L.; Collis, S. M.

    2012-12-01

    Mammatus clouds forming on the base of a convective anvil were observed over the DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility located around Lamont, Oklahoma. New ARM instruments documented an unique example of mammatus clouds, providing unprecedented dynamical and microphysical insights on mammatus formation and evolution. It is believed that this dataset is the first to combine high-resolution vertically-pointing cloud radar Doppler spectra and moment observations (35 GHz) with novel scanning weather radar modes (3 cm and 5 cm wavelength) to explore mammatus cloud fields and offer additional 2D and 3D characterization. The suite of ARM facility platforms visually documented the mammatus field overhead and included multiple radiosonde releases at 3-hour separation to capture the thermodynamic structure of the environment in the immediate vicinity of these mammatus. Additional ARM resources (profiler, ceilometer, lidar) are consulted to confirm the quality of the ARM radar observations and assess radar capabilities to reliably designate mammatus cloud features. The wealth of ARM observations is compared to the results of high-resolution numerical simulations of mammatus, having initial conditions forced using ARM radiosonde observations and ARM continuous model forcing datasets.

  16. Combined laser ultrasonics, laser heating, and Raman scattering in diamond anvil cell system.

    PubMed

    Zinin, Pavel V; Prakapenka, Vitali B; Burgess, Katherine; Odake, Shoko; Chigarev, Nikolay; Sharma, Shiv K

    2016-12-01

    We developed a multi-functional in situ measurement system under high pressure equipped with a laser ultrasonics (LU) system, Raman device, and laser heating system (LU-LH) in a diamond anvil cell (DAC). The system consists of four components: (1) a LU-DAC system (probe and pump lasers, photodetector, and oscilloscope) and DAC; (2) a fiber laser, which is designed to allow precise control of the total power in the range from 2 to 100 W by changing the diode current, for heating samples; (3) a spectrometer for measuring the temperature of the sample (using black body radiation), fluorescence spectrum (spectrum of the ruby for pressure measurement), and Raman scattering measurements inside a DAC under high pressure and high temperature (HPHT) conditions; and (4) an optical system to focus laser beams on the sample and image it in the DAC. The system is unique and allows us to do the following: (a) measure the shear and longitudinal velocities of non-transparent materials under HPHT; (b) measure temperature in a DAC under HPHT conditions using Planck's law; (c) measure pressure in a DAC using a Raman signal; and (d) measure acoustical properties of small flat specimens removed from the DAC after HPHT treatment. In this report, we demonstrate that the LU-LH-DAC system allows measurements of velocities of the skimming waves in iron at 2580 K and 22 GPa.

  17. AC calorimetry of H2O at pressures up to 9 GPa in diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Geballe, Zachary M.; Struzhkin, Viktor V.

    2017-06-01

    If successfully developed, calorimetry at tens of GPa of pressure could help characterize phase transitions in materials such as high-pressure minerals, metals, and molecular solids. Here, we extend alternating-current calorimetry to 9 GPa and 300 K in a diamond anvil cell and use it to study phase transitions in H2O. In particular, water is loaded into the sample chambers of diamond-cells, along with thin metal heaters (1 μm-thick platinum or 20 nm-thick gold on a glass substrate) that drive high-frequency temperature oscillations (20 Hz to 600 kHz; 1 to 10 K). The heaters also act as thermometers via the third-harmonic technique, yielding calorimetric data on (1) heat conduction to the diamonds and (2) heat transport into substrate and sample. Using this method during temperature cycles from 300 to 200 K, we document melting, freezing, and proton ordering and disordering transitions of H2O at 0 to 9 GPa, and characterize changes in thermal conductivity and heat capacity across these transitions. The technique and analysis pave the way for calorimetry experiments on any non-metal at pressures up to ˜100 GPa, provided a thin layer (several μm-thick) of thermal insulation supports a metallic thin-film (tens of nm thick) Joule-heater attached to low contact resistance leads inside the sample chamber of a diamond-cell.

  18. Measuring temperatures in a laser-heated diamond-anvil cell at Yale University

    NASA Astrophysics Data System (ADS)

    Lee, K. K.; Amulele, G.; Benedetti, L. R.

    2009-12-01

    We describe a newly-built double-sided laser-heating system in the High-Pressure Diamond-Anvil Cell (DAC) Laboratory at Yale University. The system uses a single power-tunable 100W near-infrared fiber laser that is split into two beams and independently focused down to a ~20 μm spot on each side of the DAC. Temperature measurements are made using both the standard spectroradiometric method, which yields a 1-D temperature profile, and the recently developed four-color technique, which allows 2-D mapping of temperature and emissivity across the sample [Campbell, A. J., Rev. Sci. Inst., 79, 015108, 2008]. Simultaneous measurement of 1-dimensional spectroradometric and 2-dimensional four-color temperatures from the same sample yields a robust temperature map on one side of the sample while a second four-color measurement on the opposite side allows monitoring of temperature in three spatial dimensions as well as in time. Initial results document consistent temperature measurement by the two techniques. This system can be used to document melting in situ [as described by Campbell, 2008]. Additionally, this system can be used to map out temperature and corresponding temperature gradients for pressure- and temperature-quenched samples for chemical analysis in recovered samples.

  19. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen

    2010-11-19

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {micro}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {micro}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  20. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Struzhkin, Viktor V.; Dalton, D. Allen; Prakapenka, Vitali B.; Kantor, Innokenty; Rivers, Mark L.

    2010-11-15

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {mu}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10 000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {mu}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  1. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen

    2010-11-03

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2–10 kHz repetition rate, 1064–1075 nm fiber laser with 1–100 μs pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 μm thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  2. Transformation-deformation bands in C60 after the treatment in a shear diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Kulnitskiy, B. A.; Blank, V. D.; Levitas, V. I.; Perezhogin, I. A.; Popov, M. Yu; Kirichenko, A. N.; Tyukalova, E. V.

    2016-04-01

    The C60 fullerene has been investigated by high-resolution transmission electron microscopy and electron energy loss spectroscopy in a shear diamond anvil cell after applying pressure and shear deformation treatment of fcc phase. Shear transformation-deformation bands are revealed consisting of shear-strain-induced nanocrystals of linearly polymerized fullerene and polytypes, the triclinic, monoclinic, and hcp C60, fragments of amorphous structures, and voids. Consequently, after pressure release, the plastic strain retains five high pressure phases, which is potentially important for their engineering applications. Localized shear deformation initially seems contradictory because high pressure phases of C60 are stronger than the initial low pressure phase. However, this was explained by transformation-induced plasticity during localized phase transformations. It occurs due to a combination of applied stresses and internal stresses from a volume reduction during phase transformations. Localized phase transformations and plastic shear deformation promote each other, which produce positive mechanochemical feedback and cascading transformation-deformation processes. Since the plastic shear in a band is much larger than is expected based on the torsion angle, five phase transformations occur in the same region with no transformation outside the band. The results demonstrate that transformation kinetics cannot be analyzed in terms of prescribed shear, and methods to measure local shear should be developed.

  3. Partitioning experiments in the laser-heated diamond anvil cell: volatile content in the Earth's core.

    PubMed

    Jephcoat, Andrew P; Bouhifd, M Ali; Porcelli, Don

    2008-11-28

    The present state of the Earth evolved from energetic events that were determined early in the history of the Solar System. A key process in reconciling this state and the observable mantle composition with models of the original formation relies on understanding the planetary processing that has taken place over the past 4.5Ga. Planetary size plays a key role and ultimately determines the pressure and temperature conditions at which the materials of the early solar nebular segregated. We summarize recent developments with the laser-heated diamond anvil cell that have made possible extension of the conventional pressure limit for partitioning experiments as well as the study of volatile trace elements. In particular, we discuss liquid-liquid, metal-silicate (M-Sil) partitioning results for several elements in a synthetic chondritic mixture, spanning a wide range of atomic number-helium to iodine. We examine the role of the core as a possible host of both siderophile and trace elements and the implications that early segregation processes at deep magma ocean conditions have for current mantle signatures, both compositional and isotopic. The results provide some of the first experimental evidence that the core is the obvious replacement for the long-sought, deep mantle reservoir. If so, they also indicate the need to understand the detailed nature and scale of core-mantle exchange processes, from atomic to macroscopic, throughout the age of the Earth to the present day.

  4. Ionic Liquids as Quasihydrostatic Pressure Media for Diamond Anvil Cell Experiments

    NASA Astrophysics Data System (ADS)

    Mayorga, Sierra; Moldowan, Kaela; Dan, Ioana; Forster, Paul; Iota, Valentin

    2012-02-01

    Ionic liquids (ILs) are salts in which the ions are poorly coordinated to the point where the eutectic mixture remains liquid at room temperature. In general, ILs exhibit high chemical and thermal stability, have extended liquid regions in the pressure-temperature domain, and can be easily obtained. Commercial ionic liquids are relatively inexpensive and custom ionic solutions can be easily synthesized by mixing common reactants. These properties make ionic liquids attractive candidates for high-pressure media in Diamond Anvil Cell (DAC) experiments. In this presentation we explore the use of ionic liquids as DAS quasihydrostatic pressure media for pressures up to 50 GPa. As a measure of hydrostaticity we monitor the splitting and peak-widths of the R1 andR 2 fluorescence lines from small ruby chips (Al2O3 :Cr^3+) imbedded in the pressure medium. We present results on a series of commercially available ionic fluids against standard pressure media: methanol-ethanol mixtures, silicone oil, sodium chloride (NaCl) and noble gases (Ar, Ne, He).

  5. Raman Spectroscopy of Serpentine and Reaction Products at High Pressure Using a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Burgess, K.; Zinin, P.; Odake, S.; Fryer, P.; Hellebrand, E.

    2012-12-01

    Serpentine is one of the most abundant hydrous phases in the altered subducting plate, and contributes a large portion of the water flux in subduction zones. Measuring and understanding the structural changes in serpentine with pressure aids our understanding of the processes ongoing in oceanic crust and subduction zones. We have conducted high-pressure/high-temperature experiments on serpentine and its dehydration reaction products using a diamond anvil cell. We used the multifunctional in-situ measurement system equipped with a Raman device and laser heating system at the University of Hawaii. Well-characterized natural serpentinite was used in the study. Pressure was determined using the shift of the fluorescence line of a ruby placed next to the sample. Raman spectra of serpentine were obtained at higher pressures than previously published, up to 15 GPa; the peak shift with pressure fits the model determined by Auzende et al. [2004] at lower pressures. Heating was done at several different pressures up to 20 GPa, and reaction products were identified using Raman. Micro-Raman techniques allow us to determine reaction progress and heterogeneity within natural samples containing olivine and serpentine. Auzende, A-L., I. Daniel, B. Reynard, C. Lemaire, F. Guyot (2004). High-pressure behavior of serpentine minerals: a Raman spectroscopic study. Phys. Chem. Minerals 31 269-277.

  6. An in situ approach to study trace element partitioning in the laser heated diamond anvil cell

    SciTech Connect

    Petitgirard, S.; Mezouar, M.; Borchert, M.; Appel, K.; Liermann, H.-P.; Andrault, D.

    2012-01-15

    Data on partitioning behavior of elements between different phases at in situ conditions are crucial for the understanding of element mobility especially for geochemical studies. Here, we present results of in situ partitioning of trace elements (Zr, Pd, and Ru) between silicate and iron melts, up to 50 GPa and 4200 K, using a modified laser heated diamond anvil cell (DAC). This new experimental set up allows simultaneous collection of x-ray fluorescence (XRF) and x-ray diffraction (XRD) data as a function of time using the high pressure beamline ID27 (ESRF, France). The technique enables the simultaneous detection of sample melting based to the appearance of diffuse scattering in the XRD pattern, characteristic of the structure factor of liquids, and measurements of elemental partitioning of the sample using XRF, before, during and after laser heating in the DAC. We were able to detect elements concentrations as low as a few ppm level (2-5 ppm) on standard solutions. In situ measurements are complimented by mapping of the chemical partitions of the trace elements after laser heating on the quenched samples to constrain the partitioning data. Our first results indicate a strong partitioning of Pd and Ru into the metallic phase, while Zr remains clearly incompatible with iron. This novel approach extends the pressure and temperature range of partitioning experiments derived from quenched samples from the large volume presses and could bring new insight to the early history of Earth.

  7. Deformation T-Cup: a new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa.

    PubMed

    Hunt, Simon A; Weidner, Donald J; McCormack, Richard J; Whitaker, Matthew L; Bailey, Edward; Li, Li; Vaughan, Michael T; Dobson, David P

    2014-08-01

    A new multi-anvil deformation apparatus, based on the widely used 6-8 split-cylinder, geometry, has been developed which is capable of deformation experiments at pressures in excess of 18 GPa at room temperature. In 6-8 (Kawai-type) devices eight cubic anvils are used to compress the sample assembly. In our new apparatus two of the eight cubes which sit along the split-cylinder axis have been replaced by hexagonal cross section anvils. Combining these anvils hexagonal-anvils with secondary differential actuators incorporated into the load frame, for the first time, enables the 6-8 multi-anvil apparatus to be used for controlled strain-rate deformation experiments to high strains. Testing of the design, both with and without synchrotron-X-rays, has demonstrated the Deformation T-Cup (DT-Cup) is capable of deforming 1-2 mm long samples to over 55% strain at high temperatures and pressures. To date the apparatus has been calibrated to, and deformed at, 18.8 GPa and deformation experiments performed in conjunction with synchrotron X-rays at confining pressures up to 10 GPa at 800 °C .

  8. Along-arc segmentation and interaction of subducting ridges with the Lesser Antilles Subduction forearc crust revealed by MCS imaging

    NASA Astrophysics Data System (ADS)

    Laigle, Mireille; Becel, Anne; Kopp, Heidrun; Lebrun, Jean-Frederic; Klaeschen, Dirk

    2010-05-01

    Among the seismic surveys carried out in the framework of the EU - THALES WAS RIGHT project in the Lesser Antilles subduction zone, the SISMANTILLES II cruise of N/O ATALANTE (IFREMER, PI M. Laigle) collected 3 375 km of multi-channel reflection seismics with its 4.5 km long, 360 channels streamer. This survey focuses on the updip portion of the contact zone between the forearc and oceanic crusts, a proxy of the updip limit of the sismogenic portion of the subduction megathrust fault. The geometry of the survey has been designed based on the results of a preliminary SISMANTILLES cruise with N/O NADIR (2001, IFREMER). It consists in a grid of profiles comprising 7 north-south strike-lines (300 km long and spaced by 15 km) crossed by 12 dip-lines (150 km long and spaced by 25 km), with an Ocean Bottom Seismometer network (OBS) deployed on the nodes of this MCS grid. We present the 12 dip-line transects spaced at about 25 km from each other and sampling a 280 km long segment of the subduction, from offshore Martinique Island in the south up to offshore Antigua Island in the north. They all have been processed on board with CGG-Veritas Geovecteur and Geocluster softwares up to post-stack time-migration with constant water velocity. Some profiles have been reprocessed at IFM-GEOMAR (Kiel, Germany) in the frame of a EU-TMR project with pre-stack depth migration (PSDM) processing after deconvolution and multiple attenuation and will be presented instead. The 12 dip-line transects reveal the trenchward-dipping forearc basement, the transition between the forearc sedimentary domain and the accretionary prism, as well as the arcward-dipping decollement and oceanic crust. The forearc basement can be followed beneath the 4 westernmost crossing strike-lines, reaching distances of 160-190 km from the volcanic arc, and up to 5 s twt beneath the sea-bottom reflection. In the northern half, together with the previous survey, 4 dip-lines reached out over the deformation front of the

  9. Tropical cyclogenesis in Eastern Atlantique: Impact of earlier passage of African Easterly Wave trough on the evolution of Mesoscale Convective Systems and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Lahat Dieng, Abdou; Eymard, Laurence; Moustapha Sall, Saidou; Lazar, Alban; Leduc-Leballeur, Marion

    2014-05-01

    A large part of Atlantic tropical depressions is generated in the Eastern basin in relation with the African Easterly Waves and the Mesoscale Convective Systems coming from the African continent. But initial surface oceanic and atmosphere conditions favoring such evolution are largely unknown. This study analyzes the structures of strengthening and dissipating MCSs evolving near the West African coast and evaluates the role of the surface oceanic condition on their evolutions. Satellite brightness temperature from Meteosat Second Generation over the summer season of 2006 and radar data for the same season between 1993 and 1999 are used to subjectively select fourteen cases of strengthening (dissipating) MCSs when they cross the Senegalese coast. With these observed MCSs locations, a lagged composite analysis is then performed using Era interim and CFSR reanalyses. Results show that the strengthening MCS composite is preceded by prior passage of an AEW near the West African coast. This first trough wave was associated with a cyclonic circulation in the low and middle troposphere and has enhanced southwest wind flow behind him feeding humidly to the strengthening MCS composite which was located in the vicinity of the second AEW trough. The contraction of the wave length associated with the two troughs was probably facilitated this supply in humidity. The Sea Surface Temperature seem contribute to the MCS enhancement through surface evaporation flux but this contribution is less important than humidity advection by the fist system. These conditions were not found in the dissipating MCS case which dissipated in a drying environment air dominated by subsidence and anticyclonic circulation. Key words: Mesoscale Convective System, African Easterly Wave, Sea Surface Temperature, tropical depression.

  10. African-American Biography.

    ERIC Educational Resources Information Center

    Martin, Ron

    1995-01-01

    Suggests sources of information for African American History Month for library media specialists who work with students in grades four through eight. Gale Research's "African-American Reference Library," which includes "African-America Biography,""African-American Chronology," and "African-American Almanac,"…

  11. The Non-coding Mammary Carcinoma Susceptibility Locus, Mcs5c, Regulates Pappa Expression via Age-Specific Chromatin Folding and Allele-Dependent DNA Methylation

    PubMed Central

    Henning, Amanda N.; Haag, Jill D.; Smits, Bart M. G.; Gould, Michael N.

    2016-01-01

    In understanding the etiology of breast cancer, the contributions of both genetic and environmental risk factors are further complicated by the impact of breast developmental stage. Specifically, the time period ranging from childhood to young adulthood represents a critical developmental window in a woman’s life when she is more susceptible to environmental hazards that may affect future breast cancer risk. Although the effects of environmental exposures during particular developmental Windows of Susceptibility (WOS) are well documented, the genetic mechanisms governing these interactions are largely unknown. Functional characterization of the Mammary Carcinoma Susceptibility 5c, Mcs5c, congenic rat model of breast cancer at various stages of mammary gland development was conducted to gain insight into the interplay between genetic risk factors and WOS. Using quantitative real-time PCR, chromosome conformation capture, and bisulfite pyrosequencing we have found that Mcs5c acts within the mammary gland to regulate expression of the neighboring gene Pappa during a critical mammary developmental time period in the rat, corresponding to the human young adult WOS. Pappa has been shown to positively regulate the IGF signaling pathway, which is required for proper mammary gland/breast development and is of increasing interest in breast cancer pathogenesis. Mcs5c-mediated regulation of Pappa appears to occur through age-dependent and mammary gland-specific chromatin looping, as well as genotype-dependent CpG island shore methylation. This represents, to our knowledge, the first insight into cellular mechanisms underlying the WOS phenomenon and demonstrates the influence developmental stage can have on risk locus functionality. Additionally, this work represents a novel model for further investigation into how environmental factors, together with genetic factors, modulate breast cancer risk in the context of breast developmental stage. PMID:27537370

  12. Time- and Space-Domain Measurements of the Thermal Conductivity in Diamond Anvil Cells

    NASA Astrophysics Data System (ADS)

    Goncharov, A. F.

    2011-12-01

    I will give an overview of recent developments of experimental techniques to measure the thermal conductivity in diamond anvil cell (DAC) under conditions of high pressure and high temperature (P-T) which are relevant for the planetary interiors. To measure the lattice contributions to the thermal conductivity, we developed a transient heating technique (THT) in the diamond anvil cell (DAC) [1]. This technique utilizes a periodic front surface temperature variation (measured by the spectroradiometry) of a metallic absorber surrounded by the material of interest and exposed to a pulsed laser radiation (10 nanoseconds pulses). We extract the thermal diffusivity of minerals by fitting the experimental results to the model finite element (FE) calculations. We have recently modified this technique for microseconds laser pulses as this allows avoiding nonequilibrium heat transfer processes. We have measured the thermal conductivity of Ar up to 50 GPa and 2500 K; the results are in agreement with the theoretical calculations [2] in the limit of high temperatures. In collaboration with a group from the University of Illinois we have utilized a time-domain thermoreflectance (TDTR)- ultrafast (femtosecond) laser pump-probe technique for measurement of the lattice thermal conductivity at high P-T conditions. We have measured the thermal conductivity of MgO up to 60 GPa and 300 K and up to 45 GPa at 600 K. The detailed results of this study will be presented in a separate paper at this Meeting. Finally, we have combined static and pulsed laser techniques to determine the thermal conductivity of Fe and its temperature dependence at high pressures up to 70 GPa and 2000 K [3]. A thin plate of Fe was positioned in an Ar medium, laser heated from one side and the temperature is being measured from both sides of the sample radiometrically. The thermal conductivity has been determined by fitting the results of FE calculations to the experimental results. These examples demonstrate

  13. Observations on the crystallization of spodumene from aqueous solutions in a hydrothermal diamond-anvil cell

    USGS Publications Warehouse

    Li, Jianking; Chou, I-Ming; Yuan, Shunda; Burruss, Robert A.

    2013-01-01

    Crystallization experiments were conducted in a new type of hydrothermal diamond-anvil cell (HDAC; type V) using LiAlSi2O6 (S) gel and H2O (W) as starting materials. A total of 21 experiments were performed at temperatures up to 950°C and pressures up to 788 MPa. In the samples with relatively low W/S ratios, many small crystals formed in the melt phase during cooling. In those with high W/S ratios, only a few crystals with smooth surfaces crystallized from the aqueous fluid in the presence of melt droplets, which were gradually consumed during crystal growth, indicating rapid transfer of material from the melt to the crystals through the aqueous fluid. The nucleation of crystals started at 710 (±70)°C and 520 (±80) MPa, and crystal growth ended at 570 (±40)°C and 320 (±90) MPa, with the cooling P-T path within the stability field of spodumene + quartz in the S-W system. The observed linear crystal growth rates in the aqueous phase, calculated by dividing the maximum length of a single crystal by the duration of the entire growth step, were 4.7 × 10−6 and 5.7 × 10−6 cm s−1 for the cooling rates of 0.5 and 1°C min−1, respectively. However, a rapid crystal growth rate of 3.6 × 10−5 cm s−1 in the aqueous fluid was observed when the components were supplied by nearby melt droplets. Our results show that when crystals nucleate in the aqueous fluid instead of the melt phase, there are fewer nuclei formed, and they grow much faster due to the low viscosity of the aqueous fluid, which accelerates diffusion of components for the growth of crystals. Therefore, the large crystals in granitic pegmatite can crystallize directly from aqueous fluids rather than hydrosilicate melt.

  14. Probing iron spin state by optical absorption in laser-heated diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Lobanov, S.; Goncharov, A. F.; Holtgrewe, N.; Lin, J. F.

    2015-12-01

    Pressure-induced spin-pairing transitions in iron-bearing minerals have been in the focus of geophysical studies1. Modern consensus is that iron spin state in the lower mantle is a complex function of crystal structure, composition, pressure, and temperature. Discontinuities in physical properties of lower mantle minerals have been revealed over the spin transition pressure range, but at room temperature. In this work, we have used a supercontinuum laser source and an intensified CCD camera to probe optical properties of siderite, FeCO3, and post-perovskite, Mg0.9Fe0.1SiO3, across the spin transition in laser-heated diamond anvil cell. Synchronously gating the CCD with the supercontinuum pulses (Fig. 1A) allowed diminishing thermal background to ~8.3*10-4. Utilizing the experimental setup we infer the spin state of ferrous iron in siderite at high pressure and temperature conditions (Fig. 1B). Similar behavior is observed for low spin ferric iron in post-perovskite at 130 GPa indicating that all iron in post-perovskite is high spin at lower mantle conditions. Also, our experimental setup holds promise for measuring radiative thermal conductivity of mantle minerals at relevant mantle conditions. Figure 1. (A) Timing of the optical absorption measurements at high temperature. (B) High temperature siderite absorption spectra at 45 GPa. Before heating and quenched after 1300 K spectra are shown in light and dark blue, respectively. Green and red curves are absorption spectra at 1200 K and 1300 K, respectively. Spectra shown in black represent room temperature absorption data on HS (43 GPa) and LS (45.5 GPa) siderite after Lobanov et al., 2015, shown for comparison.

  15. Time-Domain X-ray Diffraction in the Pulsed Laser Heated Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Prakapenka, V.; Goncharov, A. F.; Struzhkin, V.; Kantor, I.; Rivers, M. L.; Dalton, D. A.

    2011-12-01

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell (DAC) at pressure up to 100 GPa and 3500 K. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 microseconds pulse width synchronized with a gated x-ray detector (Pilatus) and time resolved radiometric temperature measurements. For the special APS hybrid mode, the measurements were also synchronized with a 500 ns long bunch carrying 88% of the ring current. This setup enables time domain measurements as a function of temperature in a micrometers time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration samples 4 micrometers thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformity as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. We will show examples of studies of the melting, thermal equation of state, and chemical reactivity. We acknowledge support from NSF EAR-0842057, DOE/ NNSA (CDAC), and EFree, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DESC0001057. X-ray diffraction measurements were performed at GSECARS (APS) supported by DOE Contract No.W-31-109- Eng-38.

  16. Precise measurements of radial temperature gradients in the laser-heated diamond anvil cell.

    PubMed

    Kavner, A; Nugent, C

    2008-02-01

    A new spectroradiometry system specialized for measuring two-dimensional temperature gradients for samples at high pressure in the laser heated diamond anvil cell has been designed and constructed at UCLA. Emitted light intensity from sample hotspots is imaged by a videocamera for real time monitoring, an imaging spectroradiometer for temperature measurement, and a high-dynamic-range camera that examines a magnified image of the two-dimensional intensity distribution of the heated spot, yielding precise measurements of temperature gradients. With this new system, most systematic errors in temperature measurement due to chromatic aberration are bypassed. We use this system to compare several different geometries of temperature measurement found in the literature, including scanning a pinhole aperture, and narrow-slit and wide-slit entrance apertures placed before the imaging spectrometer. We find that the most accurate way of measuring a temperature is to use the spectrometer to measure an average hotspot temperature and to use information from the imaging charge coupled device to calculate the temperature distribution to the hotspot. We investigate the effects of possible wavelength- and temperature-dependent emissivity, and evaluate their errors. We apply this technique to measure the anisotropy in temperature distribution of highly oriented graphite at room temperature and also at high pressures. A comparison between model and experiment demonstrates that this system is capable of measuring thermal diffusivity in anisotropic single crystals and is also capable of measuring relative thermal diffusivity at high pressures and temperatures among different materials. This shows the possibility of using this system to provide information about thermal diffusivity of materials at high pressure and temperature.

  17. Twin sample chamber for simultaneous comparative transport measurements in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Schaeffer, Anne Marie J.; Deemyad, Shanti

    2013-09-01

    In static high pressure experiments, performed within a diamond anvil cell (DAC), several different methods of thermometry may be employed to determine the temperature of the sample. Due to different DAC designs or particular experimental designs or goals, uncertainties in the determination of the temperature of a given sample exist. To overcome the inaccuracy in comparing the temperature dependence of transport properties of different materials at high pressure, we have used a novel design of resistivity measurement in a twin sample chamber built on an insulated gasket in a DAC. In this design, the transport properties of two samples will be measured simultaneously and therefore the two samples will always be in the same relative temperatures. The uncertainties in the temperatures of the two samples will be exactly the same and therefore their relative phase diagram will be compared precisely. The pressures of the chambers can be slightly different and is easily determined by the ruby pieces placed in each chamber. To demonstrate the feasibility of this method we have compared the superconducting properties of two YBa2Cu3O7-x (0 ≤ x ≤ 0.65) samples with slightly different superconducting transition temperatures at ambient pressure as a function of pressures up to 11 GPa. The upper limit of the pressure achieved using this design would be lower than single chamber gaskets. The highest achievable pressure, as in a conventional single hole setup, depends upon the thickness of the gasket, the culet size, the size, and symmetry of the sample chamber. For the twin chamber, it also depends upon the separation of the holes from each other as well as from the edge of the culet.

  18. Adaptive MCS selection and resource planning for energy-efficient communication in LTE-M based IoT sensing platform.

    PubMed

    Dao, Nhu-Ngoc; Park, Minho; Kim, Joongheon; Cho, Sungrae

    2017-01-01

    As an important part of IoTization trends, wireless sensing technologies have been involved in many fields of human life. In cellular network evolution, the long term evolution advanced (LTE-A) networks including machine-type communication (MTC) features (named LTE-M) provide a promising infrastructure for a proliferation of Internet of things (IoT) sensing platform. However, LTE-M may not be optimally exploited for directly supporting such low-data-rate devices in terms of energy efficiency since it depends on core technologies of LTE that are originally designed for high-data-rate services. Focusing on this circumstance, we propose a novel adaptive modulation and coding selection (AMCS) algorithm to address the energy consumption problem in the LTE-M based IoT-sensing platform. The proposed algorithm determines the optimal pair of MCS and the number of primary resource blocks (#PRBs), at which the transport block size is sufficient to packetize the sensing data within the minimum transmit power. In addition, a quantity-oriented resource planning (QORP) technique that utilizes these optimal MCS levels as main criteria for spectrum allocation has been proposed for better adapting to the sensing node requirements. The simulation results reveal that the proposed approach significantly reduces the energy consumption of IoT sensing nodes and #PRBs up to 23.09% and 25.98%, respectively.

  19. Adaptive MCS selection and resource planning for energy-efficient communication in LTE-M based IoT sensing platform

    PubMed Central

    Dao, Nhu-Ngoc; Park, Minho; Kim, Joongheon

    2017-01-01

    As an important part of IoTization trends, wireless sensing technologies have been involved in many fields of human life. In cellular network evolution, the long term evolution advanced (LTE-A) networks including machine-type communication (MTC) features (named LTE-M) provide a promising infrastructure for a proliferation of Internet of things (IoT) sensing platform. However, LTE-M may not be optimally exploited for directly supporting such low-data-rate devices in terms of energy efficiency since it depends on core technologies of LTE that are originally designed for high-data-rate services. Focusing on this circumstance, we propose a novel adaptive modulation and coding selection (AMCS) algorithm to address the energy consumption problem in the LTE-M based IoT-sensing platform. The proposed algorithm determines the optimal pair of MCS and the number of primary resource blocks (#PRBs), at which the transport block size is sufficient to packetize the sensing data within the minimum transmit power. In addition, a quantity-oriented resource planning (QORP) technique that utilizes these optimal MCS levels as main criteria for spectrum allocation has been proposed for better adapting to the sensing node requirements. The simulation results reveal that the proposed approach significantly reduces the energy consumption of IoT sensing nodes and #PRBs up to 23.09% and 25.98%, respectively. PMID:28796804

  20. A novel diamond anvil cell for x-ray diffraction at cryogenic temperatures manufactured by 3D printing.

    PubMed

    Jin, H; Woodall, C H; Wang, X; Parsons, S; Kamenev, K V

    2017-03-01

    A new miniature high-pressure diamond anvil cell was designed and constructed using 3D micro laser sintering technology. This is the first application of the use of rapid prototyping technology to construct high-pressure apparatus. The cell is specifically designed for use as an X-ray diffraction cell that can be used with commercially available diffractometers and open-flow cryogenic equipment to collect data at low temperature and high pressure. The cell is constructed from stainless steel 316L and is about 9 mm in diameter and 7 mm in height, giving it both small dimensions and low thermal mass, and it will fit into the cooling envelope of a standard Cryostream(TM) cooling system. The cell is clamped using a customized miniature buttress thread of diameter 7 mm and pitch of 0.5 mm enabled by 3D micro laser sintering technology; such dimensions are not attainable using conventional machining. The buttress thread was used as it has favourable uniaxial load properties allowing for higher pressure and better anvil alignment. The clamp can support the load of at least 1.5 kN according to finite element analysis (FEA) simulations. FEA simulations were also used to compare the performance of the standard thread and the buttress thread, and demonstrate that stress is distributed more uniformly in the latter. Rapid prototyping of the pressure cell by the laser sintering resulted in a substantially higher tensile yield strength of the 316L stainless steel (675 MPa compared to 220 MPa for the wrought type of the same material), which increased the upper pressure limit of the cell. The cell is capable of reaching pressures of up to 15 GPa with 600 μm diameter culets of diamond anvils. Sample temperature and pressure changes on cooling were assessed using X-ray diffraction on samples of NaCl and HMT-d12.

  1. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    SciTech Connect

    Wang, Xuebing; Chen, Ting; Qi, Xintong; Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng; Kung, Jennifer; Yu, Tony; Wang, Yanbin

    2015-08-14

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al{sub 2}O{sub 3} were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al{sub 2}O{sub 3} pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.

  2. A novel diamond anvil cell for x-ray diffraction at cryogenic temperatures manufactured by 3D printing

    NASA Astrophysics Data System (ADS)

    Jin, H.; Woodall, C. H.; Wang, X.; Parsons, S.; Kamenev, K. V.

    2017-03-01

    A new miniature high-pressure diamond anvil cell was designed and constructed using 3D micro laser sintering technology. This is the first application of the use of rapid prototyping technology to construct high-pressure apparatus. The cell is specifically designed for use as an X-ray diffraction cell that can be used with commercially available diffractometers and open-flow cryogenic equipment to collect data at low temperature and high pressure. The cell is constructed from stainless steel 316L and is about 9 mm in diameter and 7 mm in height, giving it both small dimensions and low thermal mass, and it will fit into the cooling envelope of a standard CryostreamTM cooling system. The cell is clamped using a customized miniature buttress thread of diameter 7 mm and pitch of 0.5 mm enabled by 3D micro laser sintering technology; such dimensions are not attainable using conventional machining. The buttress thread was used as it has favourable uniaxial load properties allowing for higher pressure and better anvil alignment. The clamp can support the load of at least 1.5 kN according to finite element analysis (FEA) simulations. FEA simulations were also used to compare the performance of the standard thread and the buttress thread, and demonstrate that stress is distributed more uniformly in the latter. Rapid prototyping of the pressure cell by the laser sintering resulted in a substantially higher tensile yield strength of the 316L stainless steel (675 MPa compared to 220 MPa for the wrought type of the same material), which increased the upper pressure limit of the cell. The cell is capable of reaching pressures of up to 15 GPa with 600 μm diameter culets of diamond anvils. Sample temperature and pressure changes on cooling were assessed using X-ray diffraction on samples of NaCl and HMT-d12.

  3. Ignoring Authentic African Literature Means Ignoring Africans

    ERIC Educational Resources Information Center

    Romano, Carlin

    2005-01-01

    Africa produces imaginative and authentic literature whose texture makes it impossible to think of Africans as statistics. African writers, however have to struggle to get recognized in America due to their culture and other racial and social differences, hence suggesting that efforts should be made to give authentic African literature its due.

  4. High-pressure FT IR measurements of crystalline methylene chloride up to 120 kbar in the diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Shimizu, H.; Xu, J.; Mao, H. K.; Bell, P. M.

    1984-03-01

    The FT IR spectra of pressure-induced crystalline CH 2Cl 2 at room temperature were measured at hydrostatic pressures up to 120 kbar in the diamond anvil cell. The pressure dependences of the internal modes (ν 3, ν 9, ν 8, and ν 2) are reported and compared with the result of Raman scattering measurements. The discontinuity of the slope (dν/d P) at ≈ 45 kbar for the ν 9 antisymmetric CCl streching mode indicates the pressure-induced second-order phase transition which seems to be triggered by the interaction between the ν 9 mode and the ν 3 symmetric CCl stretching mode.

  5. Use of Taylor rod-on-anvil impact experiments to investigate high strain rate behavior in polyolefins

    NASA Astrophysics Data System (ADS)

    Luce, Amanda; Breidenich, Jennifer; Kannan, Abhiram; Thadhani, Naresh; Bucknall, David G.

    2017-01-01

    Taylor rod-on-anvil impact experiments have been performed on a range of polyolefins. At impact velocity greater than 250 m/s there are significant differences observed in the deformation behavior between the four polymers, which cannot be explained based on current understanding. During the initial stages of impact, mechno-luminescence is observed in all polymers and at all impact velocities. The location and length scale of this luminescence is consistent with the observed location of temperature increases that approach, and in some instances, exceed the melt point of the polymers.

  6. 3D analytical investigation of melting at lower mantle conditions in the laser-heated diamond anvil cel

    NASA Astrophysics Data System (ADS)

    Nabiei, F.; Cantoni, M.; Badro, J.; Dorfman, S. M.; Gaal, R.; Piet, H.; Gillet, P.

    2015-12-01

    The diamond anvil cell is a unique tool to study materials under static pressures up to several hundreds of GPa. It is possible to generate temperatures as high as several thousand degrees in the diamond anvil cell by laser heating. This allows us to achieve deep mantle conditions in the laser-heated diamond anvil cell (LHDAC). The small heated volume is surrounded by thermally conductive diamond anvils results in high temperature gradients which affect phase transformation and chemical distribution in the LH-DAC. Analytical characterization of samples in three dimensions is essential to fully understand phase assemblages and equilibrium in LHDAC. In this study we used San Carlos olivine as a starting material as a simple proxy to deep mantle composition. Three samples were melted at ~3000 K and at ~45 GPa for three different durations ranging from 1 to 6 minutes; two other samples were melted at 30 GPa and 70 GPa. All samples were then sliced by focused ion beam (FIB). From each slice, an electron image and energy dispersive X-ray (EDX) map were acquired by scanning electron microscope (SEM) in the dual beam FIB instrument. These slices were collected on one half of the heated area in each sample, from which we obtained 3D elemental and phase distribution. The other half of the heated area was used to extract a 100 nm thick section for subsequent analysis by analytical transmission electron microscopy (TEM) to obtain diffraction patterns and high resolution EDX maps. 3D reconstruction of SEM EDX results shows at least four differentiated regions in the heated area for all samples. The exact Fe and Mg compositions mentioned below are an example of the sample melted at 45 GPa for 6 minutes. The bulk of the heated are is surrounded by ferropericlase (Mg0.92, Fe0.08)O shell (Fp). Inside this shell we find a thick region of (Mg,Fe)SiO3 perovskite-structured bridgmanite (Brg) coexisting with Fp. In the center lies a Fe-rich core which is surrounded by magnesiow

  7. Note: The effect of sample insulation on experiment precision of resistivity measurement in a diamond anvil cell.

    PubMed

    Peng, Gang; Han, Yonghao; Gao, Chunxiao; Ma, Yanzhang; Wu, Baojia; Liu, Cailong; Liu, Bao; Hu, Tingjing; Wang, Yue; Cui, Xiaoyan; Ren, Wanbin; Liu, Hongwu; Zou, Guangtian

    2010-03-01

    By use of electrical field analysis method, the accuracy of electrical resistivity measurement with the van der Pauw method in a diamond anvil cell (DAC) was investigated for the situation that sample and gasket were electrically shorted. It is revealed that metal gasket could not be used in electrical measurement in DAC if the inside wall of the sample chamber was not insulated. When the shorted area was less than 20% of the inside wall of the sample chamber, the relative error was smaller than 10%. Once the shorted area exceeded 25%, the relative error increased rapidly.

  8. Note: The effect of sample insulation on experiment precision of resistivity measurement in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Peng, Gang; Han, Yonghao; Gao, Chunxiao; Ma, Yanzhang; Wu, Baojia; Liu, Cailong; Liu, Bao; Hu, Tingjing; Wang, Yue; Cui, Xiaoyan; Ren, Wanbin; Liu, Hongwu; Zou, Guangtian

    2010-03-01

    By use of electrical field analysis method, the accuracy of electrical resistivity measurement with the van der Pauw method in a diamond anvil cell (DAC) was investigated for the situation that sample and gasket were electrically shorted. It is revealed that metal gasket could not be used in electrical measurement in DAC if the inside wall of the sample chamber was not insulated. When the shorted area was less than 20% of the inside wall of the sample chamber, the relative error was smaller than 10%. Once the shorted area exceeded 25%, the relative error increased rapidly.

  9. Finite element analysis of the effect of electrode resistivity on resistivity measurement in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Huang, Xiaowei; Gao, Chunxiao; Zhang, Dongmei; Li, Ming; He, Chunyuan; Hao, Aimin; Yu, Cuiling; Sang, Chong; Liu, Cailong; Wang, Yue; Guan, Rui; Li, Dongmei; Zou, Guangtian; Ma, Yanzhang

    2007-05-01

    The effect of electrode resistivity on the in situ resistivity measurement in a diamond anvil cell was studied using finite element analysis. The theoretical analysis reveals that the origin of significant error for a thin sample is mainly caused by the resistivity difference between the electrodes and the sample. The authors found that reducing such resistivity differences can improve the accuracy. The result shows that the van der Pauw method [L. J. van der Pauw, Philips Tech. Rev. 20, 220 (1958)] can provide more accurate results for thin samples compared with the four-point probe method. This approach provides means to simulate actual experiments and to eliminate the measurement error.

  10. Peculiar Features of Microstructure Formation and Microhardness Variations During Torsional Straining of Tantalum Specimens in Bridgman Anvils

    NASA Astrophysics Data System (ADS)

    Ditenberg, I. A.; Tymentsev, A. N.; Korznikov, A. V.

    2015-04-01

    Using the method of transmission electron microscopy, peculiar features of evolution of microstructure and variations in microhardness of Та are investigated under torsional loading in the Bridgman anvil as a function of plastic deformation at room temperature. A quantitative examination of grain and defect's structure of the material under study and the values of local internal stresses is performed in different loading stages. The mechanisms of formation of submicrocrystalline and nanostructured states are analyzed and so is the microstructure variation as a function of the defect-structure characteristics, strain level, and spacing from the axis of torsion.

  11. Techniques for determining pressure in the hydrothermal diamond- anvil cell: behavior and identification of ice polymorphs (I, III, V, VI)

    USGS Publications Warehouse

    Haselton, H.T.; I-Ming, Chou; Shen, A.H.; Bassett, William A.

    1995-01-01

    For H2O densities > 1.0 g/cm3, a determination of the ice melting temperature provides the density information required to calculate the P-T path that the sample in a hydrothermal diamond-anvil cell follows when the sample is heated isochorically. The principal difficulty is the identification of the polymorph because of metastable behavior of ices in the H2O system. Usually, an accurate identification of the liquidus ice phase can be made without analytical instrumentation and requires only careful observations. -Authors

  12. Liquid mercury sound velocity measurements under high pressure and high temperature by picosecond acoustics in a diamond anvils cell.

    PubMed

    Decremps, F; Belliard, L; Couzinet, B; Vincent, S; Munsch, P; Le Marchand, G; Perrin, B

    2009-07-01

    Recent improvements to measure ultrasonic sound velocities of liquids under extreme conditions are described. Principle and feasibility of picosecond acoustics in liquids embedded in a diamond anvils cell are given. To illustrate the capability of these advances in the sound velocity measurement technique, original high pressure and high temperature results on the sound velocity of liquid mercury up to 5 GPa and 575 K are given. This high pressure technique will certainly be useful in several fundamental and applied problems in physics and many other fields such as geophysics, nonlinear acoustics, underwater sound, petrology or physical acoustics.

  13. Lifecycles and radiative impacts of anvil cirrus outflow during the maritime continent thunderstorm experiment

    NASA Astrophysics Data System (ADS)

    Jensen, Michael Philip

    2000-10-01

    The Maritime Continent Thunderstorm Experiment took place from 13 November to 10 December 1995 on the Tiwi Islands, which are located approximately 70 km north of Darwin, Australia. As part of this experiment a suite of surface remote sensing instruments including a dual-wavelength millimeter radar, a 10 cm vertically pointing radar and broad-band radiometers were deployed on the northwest comer of Melville Island (11.4S, 130.41E). A 5.2 cm scanning radar was located at Nguiu (10.23A, 130.62E) on the southeast comer of Bathurst Island. The radiative impact of three separate cirrus anvil systems ire investigated. In order to do this, the three- dimensional structure of ice water in the cloud is parameterized from the 5.2 cm radar reflectivity measurements through a Z-IWC relationship. The three- dimensional ice water structure is put into a two-steam radiative transfer model using an independent pixel approximation for several different stages in the lifecycle of the cloud system. Radiative heating/cooling occurs at many different levels through the cloud area. Our analysis shows that the top layer of the cloud is optically thick. Therefore, this variability in the height of radiative heating/cooling is due to variability in cloud top height. There is a distinct difference between the average radiative heating profile in the presence of island-based convection compared to oceanic convection. The island-based convection results in a profile which concentrates cloud- top solar heating and infrared cooling higher in the atmosphere and with a greater magnitude than does oceanic convection. A comparison of the large-scale radiative impact of the island-based thunderstorms upon the net radiative heating in the tropical western Pacific shows that the presence of these thunderstorms greatly changes the deposition of radiational energy in the atmospheric column. Therefore, when considering the energy balance over the tropical western Pacific it is important to treat the

  14. Comparisons of Anvil Cirrus Spatial Characteristics between Airborne Observations in DC3 Campaign and WRF Simulations

    NASA Astrophysics Data System (ADS)

    D'Alessandro, J.; Diao, M.; Chen, M.

    2015-12-01

    John D'Alessandro1, Minghui Diao1, Ming Chen2, George Bryan2, Hugh Morrison21. Department of Meteorology and Climate Science, San Jose State University2. Mesoscale & Microscale Meteorology Division, National Center for Atmospheric Research, Boulder, CO, 80301 Ice crystal formation requires the prerequisite condition of ice supersaturation, i.e., relative humidity with respect to ice (RHi) greater than 100%. The formation and evolution of ice supersaturated regions (ISSRs) has large impact on the subsequent formation of ice clouds. To examine the characteristics of simulated ice supersaturated regions at various model spatial resolutions, case studies between airborne in-situ measurements in the NSF Deep Convective, Clouds and Chemistry (DC3) campaign (May - June 2012) and WRF simulations are conducted in this work. Recent studies using ~200 m in-situ observations showed that ice supersaturated regions are mostly around 1 km in horizontal scale (Diao et al. 2014). Yet it is still unclear if such observed characteristics can be represented by WRF simulations at various spatial resolutions. In this work, we compare the WRF simulated anvil cirrus spatial characteristics with those observed in the DC3 campaign over the southern great plains in US. The WRF model is run at 1 km and 3 km horizontal grid spacing with a recent update of Thompson microphysics scheme. Our comparisons focus on the spatial characteristics of ISSRs and cirrus clouds, including the distributions of their horizontal scales, the maximum relative humidity with respect to ice (RHi) and the relationship between RHi and temperature. Our previous work on the NCAR CM1 cloud-resolving model shows that the higher resolution runs (i.e., 250m and 1km) generally have better agreement with observations than the coarser resolution (4km) runs. We will examine if similar trend exists for WRF simulations in deep convection cases. In addition, we will compare the simulation results between WRF and CM1, particularly

  15. Africans in America.

    ERIC Educational Resources Information Center

    Hart, Ayanna; Spangler, Earl

    This book introduces African-American history and culture to children. The first Africans in America came from many different regions and cultures, but became united in this country by being black, African, and slaves. Once in America, Africans began a long struggle for freedom which still continues. Slavery, the Civil War, emancipation, and the…

  16. African Outreach Workshop 1974.

    ERIC Educational Resources Information Center

    Schmidt, Nancy J.

    This report discusses the 1974 African Outreach Workshop planned and coordinated by the African Studies Program at the University of Illinois at Urbana-Champaign. Its major aim was to assist teachers in developing curriculum units on African using materials available in their local community. A second aim was for the African Studies Program to…

  17. Use of a multichannel collimator for structural investigation of low-Z dense liquids in a diamond anvil cell: validation on fluid H2 up to 5 GPa.

    PubMed

    Weck, Gunnar; Garbarino, Gaston; Ninet, Sandra; Spaulding, Dylan; Datchi, Frederic; Loubeyre, Paul; Mezouar, Mohamed

    2013-06-01

    We report the first application of a multichannel collimator (MCC) to perform quantitative structure factor measurements of dense low-Z fluids in a diamond anvil cell (DAC) using synchrotron x-ray diffraction. The MCC design, initially developed for the Paris-Edinburgh large volume press geometry, has been modified for use with diamond anvil cells. A good selectivity of the diffracted signal of the dense fluid sample is obtained due to a large rejection of the Compton diffusion from the diamond anvils. The signal to background ratio is significantly improved. We modify previously developed analytical techniques for quantitative measurement of the structure factor of fluids in DACs [J. H. Eggert, G. Weck, P. Loubeyre, and M. Mezouar, Phys. Rev. B 65, 174105 (2002)] to account for the contribution of the MCC. We present experimental results on liquids argon and hydrogen at 296 K to validate our method and test its limits, respectively.

  18. High quality x-ray absorption spectroscopy measurements with long energy range at high pressure using diamond anvil cell

    SciTech Connect

    Hong, X.; Newville, M.; Prakapenka, V.B.; Rivers, M.L.; Sutton, S.R.

    2009-07-31

    We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective method to obtain accurate XAFS spectrum free from DAC induced glitches has been lacking. It was found that these glitches, whose energy positions are very sensitive to the relative orientation between DAC and incident x-ray beam, can be effectively eliminated using an iterative algorithm based on repeated measurements over a small angular range of DAC orientation, e.g., within {+-}3{sup o} relative to the x-ray beam direction. Demonstration XAFS spectra are reported for rutile-type GeO{sub 2} recorded by traditional ambient pressure and high pressure DAC methods, showing similar quality at 440 eV above the absorption edge. Accurate XAFS spectra of GeO{sub 2} glass were obtained at high pressure up to 53 GPa, providing important insight into the structural polymorphism of GeO{sub 2} glass at high pressure. This method is expected be applicable for in situ XAFS measurements using a diamond anvil cell up to ultrahigh pressures.

  19. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction

    PubMed Central

    Binns, Jack; Kamenev, Konstantin V.; McIntyre, Garry J.; Moggach, Stephen A.; Parsons, Simon

    2016-01-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions. PMID:27158503

  20. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction.

    PubMed

    Binns, Jack; Kamenev, Konstantin V; McIntyre, Garry J; Moggach, Stephen A; Parsons, Simon

    2016-05-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions.

  1. The Hydrothermal Diamond Anvil Cell (HDAC) for raman spectroscopic studies of geologic fluids at high pressures and temperatures

    USGS Publications Warehouse

    Schmidt, Christian; Chou, I-Ming; Dubessy, Jean; Caumon, Marie-Camille; Pérez, Fernando Rull

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ⬚~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  2. Chapter 7: The hydrothermal diamond anvil cell (HDAC) for Raman spectroscopic studies of geological fluids at high pressures and temperatures

    USGS Publications Warehouse

    Schmidt, Christian; Chou, I-Ming; Dubessy, J.; Caumon, M.-C.; Rull, F.

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  3. Diamond dissolution and the production of methane and other carbon-bearing species in hydrothermal diamond-anvil cells

    USGS Publications Warehouse

    Chou, I.-Ming; Anderson, Alan J.

    2009-01-01

    Raman analysis of the vapor phase formed after heating pure water to near critical (355-374 ??C) temperatures in a hydrothermal diamond-anvil cell (HDAC) reveals the synthesis of abiogenic methane. This unexpected result demonstrates the chemical reactivity of diamond at relatively low temperatures. The rate of methane production from the reaction between water and diamond increases with increasing temperature and is enhanced by the presence of a metal gasket (Re, Ir, or Inconel) which is compressed between the diamond anvils to seal the aqueous sample. The minimum detection limit for methane using Raman spectroscopy was determined to be ca. 0.047 MPa, indicating that more than 1.4 nanograms (or 8.6 ?? 10-11 mol) of methane were produced in the HDAC at 355 ??C and 30 MPa over a period of ten minutes. At temperatures of 650 ??C and greater, hydrogen and carbon dioxide were detected in addition to methane. The production of abiogenic methane, observed in all HDAC experiments where a gasket was used, necessitates a reexamination of the assumed chemical systems and intensive parameters reported in previous hydrothermal investigations employing diamonds. The results also demonstrate the need to minimize or eliminate the production of methane and other carbonic species in experiments by containing the sample within a HDAC without using a metal gasket.

  4. Elastic Properties of Iron in a Diamond Anvil Cell Using Laser Ultrasonics Technique up to 56 GPa

    NASA Astrophysics Data System (ADS)

    Burgess, K.; Zinin, P.; Prakapenka, V.; Chigarev, N.

    2013-12-01

    We present results on direct measurements of shear and longitudinal wave velocities in iron under high pressure up to 56 GPa. The measurements were conducted using laser ultrasonics (LU) in diamond anvil cells (DAC), LU-DAC technique 1. The steel gasket itself was used for the measurements to avoid reflections from a pressure medium. The way the sample is loaded in DAC allows measurement of acoustical wave velocities with two different configurations: acoustic waves propagated inside the specimen are excited and detected by a pump laser and a probe laser located (a) on the same side of the specimen or (b) on opposite sides of the specimen. The signals detected are in agreement with those measured previously at lower pressures 1. 1 Chigarev, N., P. Zinin, L.-C. Ming, G. Amulele, A. Bulou, and V. Gusev (2008), Laser generation and detection of longitudinal and shear acoustic waves in a diamond anvil cell, App. Phys. Lett., 93(18), 181905-181905-181903, doi: 10.1063/1.3013587.

  5. Effect of laser annealing of pressure gradients in a diamond-anvil cell using common solid pressure media.

    PubMed

    Uts, Ilya; Glazyrin, Konstantin; Lee, Kanani K M

    2013-10-01

    Pressure media are one of the most effective deterrents of pressure gradients in diamond-anvil cell (DAC) experiments. The media, however, become less effective with increasing pressure, particularly for solid pressure media. One of the most popular ways of alleviating the increase in pressure gradients in DAC samples is through laser annealing of the sample. We explore the effectiveness of this technique for six common solid pressure media that include: alkali metal halides LiF, NaCl, KCl, CsCl, KBr, as well as amorphous SiO2. Pressure gradients are determined through the analysis of the first-order diamond Raman band across the sample before and after annealing the sample with a near-infrared laser to temperatures between ~2000 and 3000 K. As expected, we find that in the absence of sample chamber geometrical changes and diamond anvil damage, laser annealing reduces pressure gradients, albeit to varying amounts. We find that under ideal conditions, NaCl provides the best deterrent to pressure gradients before and after laser annealing, at least up to pressures of 60 GPa and temperatures between ~2000 and 3000 K. Amorphous SiO2, on the other hand, transforms in to harder crystalline stishovite upon laser annealing at high pressures resulting in increased pressure gradients upon further compression without laser annealing.

  6. Use of Taylor Rod-on-Anvil Impact Experiments to Investigate High Strain Rate Behaviour in Polyolefins

    NASA Astrophysics Data System (ADS)

    Bucknall, David; Luce, Amanda; Kannan, Abhiram; Breidenich, Jennifer; Thadhani, Naresh

    2015-06-01

    The high strain rate deformation and mechano-lumination of various polyethylenes and polypropylene is studied using Taylor rod-on-anvil impact testing. Polypropylene and low density (LDPE), high density (HDPE), and ultra high molecular weight (UHMWPE) polyethylene samples were impacted against a hardened steel anvil at velocities ranging from 50-500 m/s. High-speed imaging, time-resolved spectroscopy, and thermal imaging are employed to track the macroscopic shape change and observe mechano-lumination and heating during impact. Additionally, electron spin resonance (ESR) and gel permeation chromatography (GPC) measurements were performed on recovered impacted samples to explain the observed deformation behavior in the various polyolefins. Time-resolved spectroscopy, coupled with ESR and GPC measurements indicate that chain scission occurs during the first few microseconds of the impact event. The observed macroscopic deformation that occurs after the observed mechano-illumination event is therefore influenced by the loss of mechanical strength associated with a drop in the molecular weight of the polymer.

  7. High pressure High Temperature X-ray studies in the laser heated diamond anvil cell - Problems and solutions -

    NASA Astrophysics Data System (ADS)

    Mezouar, M.; Garbarino, G.; Svitlik, V.; Dewaele, A.

    2016-12-01

    The laser-heated diamond anvil cell (DAC) is the only static technique that can create extreme temperatures at extreme pressures (P>200 GPa). Temperatures in excess of 5000K can be achieved for samples under pressure in diamond cells by heating with high-power infrared lasers. Because of their low absorption by the diamond anvils, hard X-rays are ideal for probing micro-samples subjected to such extreme conditions. The array of X-ray techniques that was initially restricted to structural measurements using X-Ray diffraction is now extended to include several others such as inelastic X-ray Scattering, Mossbauer spectroscopy and EXAFS. As a direct consequence, many scientific breakthroughs have been achieved across fields ranging from Earth and planetary sciences to fundamental physics, chemistry and materials science. However, despite these important technical and scientific achievements, this kind of experiments still remains very challenging. The difficulties originate from multiple factors including undesired chemical reactions, inaccurate high P-T metrology, and uncertainty in the relative alignment of X-ray and laser beams. In melting studies using X-rays, additional problems can occur such as the use of an unambiguous melting criterion. In this presentation, these problems will be discussed and possible solutions proposed.

  8. High quality x-ray absorption spectroscopy measurements with long energy range at high pressure using diamond anvil cell

    PubMed Central

    Hong, Xinguo; Newville, Matthew; Prakapenka, Vitali B.; Rivers, Mark L.; Sutton, Stephen R.

    2009-01-01

    We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective method to obtain accurate XAFS spectrum free from DAC induced glitches has been lacking. It was found that these glitches, whose energy positions are very sensitive to the relative orientation between DAC and incident x-ray beam, can be effectively eliminated using an iterative algorithm based on repeated measurements over a small angular range of DAC orientation, e.g., within ±3° relative to the x-ray beam direction. Demonstration XAFS spectra are reported for rutile-type GeO2 recorded by traditional ambient pressure and high pressure DAC methods, showing similar quality at 440 eV above the absorption edge. Accurate XAFS spectra of GeO2 glass were obtained at high pressure up to 53 GPa, providing important insight into the structural polymorphism of GeO2 glass at high pressure. This method is expected be applicable for in situ XAFS measurements using a diamond anvil cell up to ultrahigh pressures. PMID:19655966

  9. Electric transport measurements on micro-structured CePt2In7 single crystals in a diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Kanter, J.; Moll, P.; Ronning, F.; Bauer, E.; Tobash, P.; Thompson, J.; Batlogg, B.

    2012-02-01

    We report Shubnikov--de Haas and resistivity measurements of CePt2In7 samples under hydrostatic pressures using a diamond anvil cell. CePt2In7 belongs to the CemMnIn3m+2n heavy fermion family. Compared to the CeMIn5 members of this group, the structure of CePt2In7 has a more two dimensional character, but also exhibits an antiferromagnetically ordered and a superconducting phase. Upon increasing pressure the AFM order is suppressed with the N'eel temperature extrapolating to a quantum critical point. The fluctuations associated with the QCP are thought to stabilize the unconventional superconducting phase. To investigate the weight of the different scattering channels the anisotropy of the resistivity above the N'eel temperature was measured for various applied pressures. Shubnikov--de Haas measurements were conducted to deduce the changes in the effective electron masses in the AFM and superconducting phases under applied hydrostatic pressure. To this end we developed a method to conduct four terminal resistance measurements on micro-structured samples inside a diamond anvil cell.

  10. Strong composition-dependent variation of MCs + calibration factors in TiO x and GeO x ( x ≤ 2) films

    NASA Astrophysics Data System (ADS)

    Gnaser, Hubert; Le, Yongkang; Su, Weifeng

    2006-07-01

    The emission of MCs + secondary ions (M designates the analyte species) from TiO x (0.2 ≤ x ≤ 2) and GeO x (0.001 ≤ x ≤ 0.8) films under Cs + bombardment was examined. The relative calibration factors of OCs +/TiCs + and OCs +/GeCs + were determined and were found to depend pronouncedly on the O/Ti and O/Ge atomic concentration ratios. Specifically, with increasing oxygen content OCs + ions form much more efficiently (as compared to TiCs + or GeCs + ions), an enhancement amounting to more than a factor of 10 for the highest oxygen concentrations. Concurrently, the formation of TiOCs + or GeOCs + ions increases drastically. For both oxide systems, an empirical relation for the oxygen-concentration dependence of the relative calibration factors could be established.

  11. Study of the Pd-Rh interdiffusion by ToF-SIMS, RBS and PIXE: Semi-quantitative depth profiles with MCs + clusters

    NASA Astrophysics Data System (ADS)

    Brison, J.; Hubert, R.; Lucas, S.; Houssiau, L.

    2006-07-01

    In this paper, ToF-SIMS was used to study the Pd-Rh interdiffusion which has a great interest in brachytherapy, a cancer treatment. The secondary ion mass spectrometry was used in the semi-quantitative MCs + mode, by detecting the RhCs + and the PdCs + molecular ions under cesium bombardment. At first, different Rh xPd y (from pure Rh to pure Pd) layers were deposited by PVD and were subsequently characterized by ToF-SIMS, RBS and PIXE. A linear relationship between the relative CsPd + yields and the Pd concentration into the Rh matrices was found. Moreover, the total sputtering yield increases linearly with the Pd concentration. Those relationships permitted to calibrate the ToF-SIMS depth profiles of annealed Pd/Rh layers and were successfully used to quantify the Pd-Rh interdiffusion.

  12. Deciphering the mechanics of an imaged fault system in the over-riding plate at the Shumagin Seismic Gap, Alaska subduction zone using MCS waveform tomography

    NASA Astrophysics Data System (ADS)

    Michaelson, C. A.; Delescluse, M.; Becel, A.; Nedimovic, M. R.; Shillington, D. J.; Louden, K. E.; Webb, S. C.

    2013-12-01

    The 2011 ALEUT program acquired 3500 km of multichannel seismic (MCS) data along a part of the western Alaska subduction zone, from the freely slipping Shumagin Seismic Gap to the locked regions in the Semidi segment and the western Kodiak asperity. The MCS profiles were acquired on the R/V Langseth using two 8-km-long streamers and span the entire locked zone on the megathrust, including the updip and downdip transitions to stable sliding. The primary goal was to characterize variations in the geometry and properties of the megathrust and the downgoing plate and relate them to downdip and along-strike changes in slip behavior and seismogenesis. The images capture the targeted megathrust reflectivity and its spatial variation. Notably, the two westernmost profiles show reflections arising from a major fault in the overriding plate within the Shumagin Seismic Gap located 75 km from the trench, which can be followed from the seafloor to the megathrust. The imaged normal fault bounds the seaward end of the Sanak forearc Cenozoic basin, formed after the Early Eocene reorganization of the Alaska subduction zone. The new reflection images also show that the seaward pair of the previously interpreted growth faults, thought to indicate deposition contemporaneous with basin subsidence, is a part of the imaged fault system. The unexpected imaging of this major fault system in the over-riding plate raises important questions: Has this fault been active during the most recent nearby megathrust earthquakes, such as the 1946 and 1948 earthquakes? Was the Sanak basin formed as a result of slip on the imaged normal fault system or is it a result of growth faulting that predates the formation of this fault? The timing and style of deformation on this fault has significant implications for both coupling on the megathrust seaward and landward of where the normal fault roots and tsunamigenesis. To complement constraints on the geometry and reflection characteristics of this structure

  13. Strategies for reducing preferred orientation and strain in powder samples for high-pressure synchrotron X-ray diffraction in diamond-anvil cells

    SciTech Connect

    Tschauner, Oliver; McClure, Jason; Nicol, Malcolm

    2010-07-20

    Among the many problems associated with high-pressure X-ray diffraction from polycrystalline samples in the diamond-anvil cell are strain and preferred orientation. A method is presented for efficiently reducing preferred orientation of powder samples compressed in diamond-anvil cells to pressures in excess of 20 GPa. This method may be successfully applied to samples of yield strength higher than alkalihalides. In addition, the problem of strain is discussed using ice-VII as an example and as an illustration of the importance of laser heating as a method of minimizing strain.

  14. DDIA-30: a Versatile Megabar Mutli-anvil Device for in-situ High Pressure Studies with White and Monochromatic Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Jing, Z.; Hilairet, N.; Yu, T.; Nishiyama, N.; Tange, Y.; Sakamaki, T.; Rivers, M. L.; Sutton, S. R.

    2010-12-01

    We report installation and test results of the DDIA-30 apparatus, a new high pressure device jointly supported by GSECARS and COMPRES. This module is now operational in the 1000 ton press in at the insertion device beamline (13-ID-D) of the Advanced Photon Source. With the operational principle similar to that of the deformation DIA (D-DIA) [1], the DDIA-30 is much larger in size, with anvil truncation edge lengths (TEL) in excess of 30 mm and hydraulic load capacity of 1000 tons. The upper and lower guide blocks have built-in differential hydraulic rams, so that the upper and lower anvils can be driven independently, generating a controlled differential stress field. When operated in single-stage mode, the device allows large samples (up to ~10 mm) to be deformed under high pressure and temperature, in a way identical to the small D-DIA that has been in operation since 2004 at 13-BM-D. The large TEL and load capacity makes DDIA-30 more attractive in double-stage configurations. Without driving the differential rams, DDIA-30 is used to compress eight second-stage cubic anvils. This 6-8 (6 first-stage and 8 second-stage anvils) configuration has been demonstrated to reach 90+ GPa with sintered diamond as second-stage anvils [2, 3]. We have tested this configuration with both LaCrO3 and TiB2 as heater materials to 35 GPa and 1500 C and successfully conducted melting experiments on selected metals and alloys with energy-dispersive diffraction and imaging. Another type of second-stage configuration is to use six DIA anvil extensions with small TELs. This 6-6 configuration [4] allows deformation experiments to be conducted without having to change the large first-stage anvils when different sized cell assemblies are desired. Recent laboratory studies using a similar device in Japan have shown that the large guide blocks have unique advantages in maintaining anvil alignment, greatly expanding capability of the deformation DIA to 25 GPa and 2000 K [5]. Monochromatic

  15. Rat Mcs1b is concordant to the genome wide association identified breast cancer risk locus at human 5q11.2 and Mier3 is a candidate cancer susceptibility gene

    PubMed Central

    denDekker, Aaron D.; Xu, Xin; Vaughn, M. Derek; Puckett, Aaron H.; Gardner, Louis L.; Lambring, Courtney J.; Deschenes, Lucas; Samuelson, David J.

    2012-01-01

    Low-penetrance alleles associated with breast cancer risk have been identified in population-based studies. Most risk loci contain either no or multiple potential candidate genes. Rat mammary carcinoma susceptibility 1b (Mcs1b) is a quantitative trait locus (QTL) on RN02 that confers decreased susceptibility when Copenhagen (COP) resistant alleles are introgressed into a Wistar Furth (WF) susceptible genome. Five WF.COP congenic lines containing COP RN02 segments were compared. One line developed an average of 3.4 ± 2.0 and 5.5 ± 3.6 mammary carcinomas per rat ± SD when females were Mcs1b resistant homozygous and Mcs1b heterozygous, respectively. These phenotypes were significantly different from susceptible genotype littermates (7.8 ± 3.1 mean mammary carcinomas per rat ± SD, P = 0.0001 and P = 0.0413, respectively). All other congenic lines tested were susceptible. Thus, Mcs1b was narrowed to 1.8 Mb of RN02 between genetic markers ENSRNOSNP2740854 and g2UL2-27. Mammary-gland-graft carcinoma-susceptibility assays were used to determine that donor (P = 0.0019), but not recipient Mcs1b genotype (P = 0.9381), was associated with ectopic mammary carcinoma outcome. Rat Mcs1b contains sequence orthologous to human 5q11.2, a breast cancer susceptibility locus identified in multiple genome-wide association studies. Human/rat MAP3K1/Map3k1 and MIER3/Mier3 are within these orthologous segments. We identified Mier3 as a candidate Mcs1b gene based on 4.5-fold higher mammary gland levels of Mier3 transcripts in susceptible compared to Mcs1b resistant females. These data suggest that the human 5q11.2 breast cancer risk allele marked by rs889312 is mammary-gland autonomous, and MIER3 is a candidate breast cancer susceptibility gene. PMID:22993404

  16. African trypanosomiasis.

    PubMed

    Maudlin, I

    2006-12-01

    Trypanosomiasis remains one of the most serious constraints to economic development in sub-Saharan Africa and, as a consequence, related research has been subject to strong social and political as well as scientific influences. The epidemics of sleeping sickness that occurred at the turn of the 20th Century focussed research efforts on what became known as 'the colonial disease'. This focus is thought to have produced 'vertical' health services aimed at this one disease, while neglecting other important health issues. Given the scale of these epidemics, and the fact that the disease is fatal if left untreated, it is unsurprising that sleeping sickness dominated colonial medicine. Indeed, recent evidence indicates that, if anything, the colonial authorities greatly under-estimated the mortality attributable to sleeping sickness. Differences in approach to disease control between Francophone and Anglophone Africa, which in the past have been considered ideological, on examination prove to be logical, reflecting the underlying epidemiological divergence of East and West Africa. These epidemiological differences are ancient in origin, pre-dating the colonial period, and continue to the present day. Recent research has produced control solutions, for the African trypanosomiases of humans and livestock, that are effective, affordable and sustainable by small-holder farmers. Whether these simple solutions are allowed to fulfil their promise and become fully integrated into agricultural practice remains to be seen. After more than 100 years of effort, trypanosomiasis control remains a controversial topic, subject to the tides of fashion and politics.

  17. Deformation experiment on fayalite using deformation-Cubic Anvil, D-CAP 700, with synchrotron X rays

    NASA Astrophysics Data System (ADS)

    Ohnuma, R. S.; Ohtani, E.; Suzuki, A.; Kubo, T.; Doi, N.; Shimojuku, A.; Kato, T.; Kikegawa, T.

    2009-12-01

    Studies of the rheological properties of rocks and minerals are important for understanding the dynamics and evolution of the Earth’s mantle. A new deformation apparatus had been proposed by Durham et al. (2002) and the new apparatus is capable of deforming samples under confining pressure up to 15GPa. Basically, the new apparatus consists of the cubic-anvil apparatus known as the DIA and two differential rams, which is called the D-DIA. The system has been introduced into synchrotron X-ray beamlines, and a procedure for measuring stress and strain using synchrotron X-rays had been developed. So far, experiments using the deformation DIA with synchrotron X-rays have been conducted at only two beamlines, the GeoSoilEnviro CARS 13-BM-D beamline of the Advanced Photon Source and the X17B2 beamline of the National Synchrotron Light Source. So, we installed a deformation cubic anvil, D-CAP 700 at the 14C2 beamline of the Photon Factory, which is essentially similar to the conventional D-DIA system. The differential rams are driven by micro-discharge pumps, and the deformation cubic anvil component is driven by MAX-III 700ton press installed at the 14C2 beamline. Two differential rams are controlled by an oil pressure controller, and both of the pressure control and the displacement control are available. The displacements of two differential rams are measured by the stroke sensor attached to rams. An incident X-ray beam was monochromatized at energy of 50 keV by a monochromater. Strain is observed from transmitted X-ray imaging of sample using the YAG:Ce single crystal phosphor and the CCD camera. Stress is measured by analyzing the two dimensional diffraction patterns of samples. The two dimensional diffraction patterns are collected by an imaging plate. Using this new deformation apparatus, D-CAP 700 and the measurement system at the 14C2 beamline of the Photon Factory, we have conducted the deformation experiments of fayalite. Samples were deformed at a confining

  18. Effect of deformation with Bridgman anvils on the structure, hardness, and critical current of a massive MgB2-based sample

    NASA Astrophysics Data System (ADS)

    Akshentsev, Yu. N.; Degtyarev, M. V.; Pilyugin, V. P.; Krinitsina, T. P.; Kuznetsova, E. I.; Blinova, Yu. V.; Sudareva, S. V.; Romanov, E. P.

    2015-05-01

    The structure and properties of synthesized massive MgB2-based samples subjected to deformation with Bridgman anvils have been studied. Deformation results in the formation of fine-grained structure of the MgB2 phase, enhancement of interconnection of grains, complete disappearance of friable MgB2-phase areas, and abrupt increase in the microhardness.

  19. Aluminum as a pressure-transmitting medium cum pressure standard for x-ray diffraction experiments to 200 GPa with diamond anvil cells

    NASA Astrophysics Data System (ADS)

    Singh, Anil K.; Liermann, Hanns-Peter; Akahama, Yuichi; Kawamura, Haruki

    2007-06-01

    The compressive strength of 99.999% pure aluminum as a function of pressure to 215 GPa has been determined from the linewidth analysis of high-pressure x-ray diffraction patterns recorded with beveled-diamond anvil cell. The strength is found to increase linearly from 0.3(1) GPa at zero pressure to 5.0(2) GPa at 200 GPa. The data to 55 GPa with flat anvil diamond cell suggest that the strength of 99.999% pure aluminum increases from 0.21(8) GPa at zero pressure to 1.1(1) GPa at 55 GPa and the extrapolated strength at 200 GPa is 3.3(4). Significantly larger strength obtained with beveled-diamond anvil cell most likely arises due to larger radial stress gradients than in the case of flat anvils. The strength of aluminum is compared with those of argon to 50 GPa and of helium to 70 GPa. The use of face-centered cubic phase of aluminum in the dual role of a pressure standard and solid pressure-transmitting medium to 200 GPa is discussed.

  20. Black African Traditional Mathematics

    ERIC Educational Resources Information Center

    Zaslavsky, Claudia

    1970-01-01

    Discusses the traditional number systems and the origin of the number names used by several African peoples living south of the Sahara. Also included are limitations in African mathematical development, and possible topics for research. (RP)

  1. Virtual Environment User Interfaces to Support RLV and Space Station Simulations in the ANVIL Virtual Reality Lab

    NASA Technical Reports Server (NTRS)

    Dumas, Joseph D., II

    1998-01-01

    Several virtual reality I/O peripherals were successfully configured and integrated as part of the author's 1997 Summer Faculty Fellowship work. These devices, which were not supported by the developers of VR software packages, use new software drivers and configuration files developed by the author to allow them to be used with simulations developed using those software packages. The successful integration of these devices has added significant capability to the ANVIL lab at MSFC. In addition, the author was able to complete the integration of a networked virtual reality simulation of the Space Shuttle Remote Manipulator System docking Space Station modules which was begun as part of his 1996 Fellowship. The successful integration of this simulation demonstrates the feasibility of using VR technology for ground-based training as well as on-orbit operations.

  2. Cryogenic gas loading in a Mao-Bell-type diamond anvil cell for high pressure-high temperature investigations.

    PubMed

    Sekar, M; Kumar, N R Sanjay; Sahu, P Ch; Chandra Shekar, N V; Subramanian, N

    2008-07-01

    A simple system for loading argon fluid at cryogenic temperatures in a Mao-Bell-type diamond anvil cell (DAC) has been developed. It is done in a two step process in which the piston-cylinder assembly alone is submerged in the cryogenic chamber for trapping the liquefied inert gas. Liquid nitrogen is used for condensing the argon gas. This system is now being efficiently used for loading liquid argon in the DAC for high pressure-high temperature experiments. The success rate of trapping liquefied argon in the sample chamber is about 75%. The performance of the gas loading system is successfully tested by carrying out direct conversion of pyrolitic graphite to diamond under high pressure-high temperature using laser heated DAC facility.

  3. A compact bellows-driven diamond anvil cell for high-pressure, low-temperature magnetic measurements.

    PubMed

    Feng, Yejun; Silevitch, D M; Rosenbaum, T F

    2014-03-01

    We present the design of an efficient bellows-controlled diamond anvil cell that is optimized for use inside the bores of high-field superconducting magnets in helium-3 cryostats, dilution refrigerators, and commercial physical property measurement systems. Design of this non-magnetic pressure cell focuses on in situ pressure tuning and measurement by means of a helium-filled bellows actuator and fiber-coupled ruby fluorescence spectroscopy, respectively. We demonstrate the utility of this pressure cell with ac susceptibility measurements of superconducting, ferromagnetic, and antiferromagnetic phase transitions to pressures exceeding 8 GPa. This cell provides an opportunity to probe charge and magnetic order continuously and with high resolution in the three-dimensional Magnetic Field-Pressure-Temperature parameter space.

  4. The Effect of By-pass Current on the Accuracy of Resistivity Measurement in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Peng, Gang; Liu, Cai-Long; Lu, Han; Han, Yong-Hao; Gao, Chun-Xiao

    2013-06-01

    We report a quantitative analysis of by-pass current effect on the accuracy of resistivity measurement in a diamond anvil cell. Due to the by-pass current, the sample resistivity calculated by the van der Pauw method is obviously smaller than the actual value and the problem becomes more serious for a high-resistivity sample. For the consideration of high accuracy of resistivity measurement, a method is presented that the inside wall of the sample chamber should be covered by a polymethylmethane layer. With this highly insulating layer, the by-pass current is effectively prevented and the current density distribution inside the sample is very close to the ideal case.

  5. A compact bellows-driven diamond anvil cell for high-pressure, low-temperature magnetic measurements

    SciTech Connect

    Feng, Yejun; Silevitch, D. M.; Rosenbaum, T. F.

    2014-03-15

    We present the design of an efficient bellows-controlled diamond anvil cell that is optimized for use inside the bores of high-field superconducting magnets in helium-3 cryostats, dilution refrigerators, and commercial physical property measurement systems. Design of this non-magnetic pressure cell focuses on in situ pressure tuning and measurement by means of a helium-filled bellows actuator and fiber-coupled ruby fluorescence spectroscopy, respectively. We demonstrate the utility of this pressure cell with ac susceptibility measurements of superconducting, ferromagnetic, and antiferromagnetic phase transitions to pressures exceeding 8 GPa. This cell provides an opportunity to probe charge and magnetic order continuously and with high resolution in the three-dimensional Magnetic Field–Pressure–Temperature parameter space.

  6. High-pressure potato starch granule gelatinization: synchrotron radiation micro-SAXS/WAXS using a diamond anvil cell.

    PubMed

    Gebhardt, R; Hanfland, M; Mezouar, M; Riekel, C

    2007-07-01

    Potato starch granules have been examined by synchrotron radiation small- and wide-angle scattering in a diamond anvil cell (DAC) up to 750 MPa. Use of a 1 microm synchrotron radiation beam allowed the mapping of individual granules at several pressure levels. The data collected at 183 MPa show an increase in the a axis and lamellar period from the edge to the center of the granule, probably due to a gradient in water content of the crystalline and amorphous lamellae. The average granules radius increases up to the onset of gelatinization at about 500 MPa, but the a axis and the lamellar periodicity remain constant or even show a decrease, suggesting an initial hydration of amorphous growth rings. The onset of gelatinization is accompanied by (i) an increase in the average a axis and lamellar periodicity, (ii) the appearance of an equatorial SAXS streak, and (iii) additional short-range order peaks.

  7. A novel and simple x-ray slit for diamond anvil cell based x-ray diffraction experiments

    NASA Astrophysics Data System (ADS)

    Irshad, K. A.; Kumar, N. R. Sanjay; Shekar, N. V. Chandra

    2017-04-01

    We report here a novel internal x-ray slit assembly to carry out laboratory based high pressure x-ray diffraction (HPXRD) experiments in a Mao Bell type diamond anvil cell. In this assembly a tiny sheet of lead with a 100 micron hole immediately below the diamond table acts as an x-ray slit. Data resolution and statistics were compared with the older slit. This novel slit assembly has two major advantages (i) eliminates cumbersome and lengthy procedure usually adopted for alignment of x-ray slit (ii) provides high flux and improved resolution due to the comparatively low beam divergence and effective utilization of the maxima of the beam profile.

  8. Hierarchical Multiscale Framework for Materials Modeling: Advances in Scale-Bridging Applied to a Taylor Anvil Impact Test of RDX

    NASA Astrophysics Data System (ADS)

    Barnes, Brian; Leiter, Kenneth; Becker, Richard; Knap, Jaroslaw; Brennan, John

    As part of a multiscale modeling effort, we present progress on a challenge in continuum-scale modeling: the direct incorporation of complex molecular-level processes in the constitutive evaluation. In this initial phase of the research we use a concurrent scale-bridging approach, with a hierarchical multiscale framework running in parallel to couple a particle-based model (the ''lower scale'') computing the equation of state (EOS) to the constitutive response in a finite-element multi-physics simulation (the ''upper scale''). The lower scale simulations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) use a force-matched coarse-grain model and dissipative particle dynamics methods, and the upper scale simulation is of a Taylor anvil impact experiment. Results emphasize use of adaptive sampling (via dynamic kriging) that accelerates time to solution, and its comparison to fully ''on the fly'' runs. Work towards inclusion of a fully reactive EOS is also discussed.

  9. A simple external resistance heating diamond anvil cell and its application for synchrotron radiation x-ray diffraction.

    PubMed

    Fan, Dawei; Zhou, Wenge; Wei, Shuyi; Liu, Yonggang; Ma, Maining; Xie, Hongsen

    2010-05-01

    A simple external heating assemblage allowing diamond anvil cell experiments at pressures up to 34 GPa and temperatures up to 653 K was constructed. This cell can be connected to the synchrotron radiation conveniently. The design and construction of this cell are fully described, as well as its applications for x-ray diffraction. Heating is carried out by using an external-heating system, which is made of NiCr resistance wire, and the temperature was measured by a NiCr-NiSi or PtRh-Pt thermocouple. We showed the performance of the new system by introducing the phase transition study of cinnabar (alpha-HgS) and thermal equation of state study of almandine at high pressure and temperature with this cell.

  10. A virtual experiment control and data acquisition system for in situ laser heated diamond anvil cell Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Subramanian, N.; Struzhkin, Viktor V.; Goncharov, Alexander F.; Hemley, Russell J.

    2010-09-01

    Doubled-sided laser heated diamond anvil cell methods allow simultaneous in situ confocal Raman measurements of materials up to megabar pressures and high temperatures. This paper describes a virtual control and data acquisition system developed to automate setups for simultaneous Raman/laser heating experiments. The system enables reduction of experiment time by ˜90% in comparison to manual operations, allowing measurements of high quality Raman spectra of even highly reactive or diffusive samples, such as hydrogen at extreme conditions using continuous wave laser heating. These types of measurements are very difficult and often impossible to obtain in a manual operation mode. Complete data archiving and accurate control of various experimental parameters (e.g., on-the-fly temperature determination and self-adjusting data collection time to avoid signal saturation) can be done, and open up possibilities of other types of experiments involving extreme conditions.

  11. Diamond-anvil cell observations of a new methane hydrate phase in the 100-MPa pressure range

    USGS Publications Warehouse

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2001-01-01

    A new high-pressure phase of methane hydrate has been identified based on its high optical relief, distinct pressure-temperature phase relations, and Raman spectra. In-situ optical observations were made in a hydrothermal diamond-anvil cell at temperatures between -40?? and 60 ??C and at pressures up to 900 MPa. Two new invariant points were located at -8.7 ??C and 99 MPa for the assemblage consisting of the new phase, structure I methane hydrate, ice Ih, and water, and at 35.3 ??C and 137 MPa for the new phase-structure I methane hydrate-water-methane vapor. Existence of the new phase is critical for understanding the phase relations among the hydrates at low to moderate pressures, and may also have important implications for understanding the hydrogen bonding in H2O and the behavior of water in the planetary bodies, such as Europa, of the outer solar system.

  12. High cloud size dependency in the applicability of the fixed anvil temperature hypothesis using global nonhydrostatic simulations

    NASA Astrophysics Data System (ADS)

    Noda, A. T.; Seiki, T.; Satoh, M.; Yamada, Y.

    2016-03-01

    The applicability of the fixed anvil temperature (FAT) hypothesis is examined using data of a global nonhydrostatic model, focusing particularly on high cloud size dependency. Decomposition of outgoing-longwave radiation (OLR) into three components, including cloud top temperature (TCT), upward cloud emissivity (ɛ), and clear-sky OLR (FCLR), reveals that the relative contributions of these three components to changes of OLR are highly dependent on cloud size. That is, the FAT hypothesis is applicable only for smaller clouds, because the contribution of TCT by those clouds is small, and ɛ is more important. In contrast, for larger clouds, the contribution of ɛ is comparable to that of TCT, and thus, both components are equally important. FCLR slightly reduces OLR but shows dependence on cloud size.

  13. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in-situ tunability

    SciTech Connect

    Palmer, Alexander; Silevitch, Daniel; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, Arnab; Ren, Yang; Rosenbaum, Thomas F.

    2015-09-04

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with that of the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we then characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as that from insulator to metal.

  14. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in-situ tunability

    DOE PAGES

    Palmer, Alexander; Silevitch, Daniel; Feng, Yejun; ...

    2015-09-04

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with that of the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we then characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide rangemore » of pressure, while at the same time making possible precise steps across abrupt phase transitions such as that from insulator to metal.« less

  15. Time-Resolved Synchrotron X-ray Diffraction on Pulse Laser Heated Iron in Diamond Anvil Cell

    SciTech Connect

    Yoo, C S; Wei, H; Dias, R; Shen, G; Smith, J; Chen, J Y; Evans, W

    2011-09-21

    The authors present time-resolved synchrotron x-ray diffraction to probe the {var_epsilon}-{delta} phase transition of iron during pulse-laser heating in a diamond anvil cell. The system utilizes a monochromatic synchrotron x-ray beam, a two-dimensional pixel array x-ray detector and a dual beam, double side laser-heating system. Multiple frames of the diffraction images are obtained in real-time every 22 ms over 500 ms of the entire pulse heating period. The results show the structural evolution of iron phases at 17 GPa, resulting in thermal expansion coefficient 1/V({Delta}V/{Delta}T){sub p} = 7.1 * 10{sup -6}/K for {var_epsilon}-Fe and 2.4 * 10{sup -5}/K for {gamma}-Fe, as well as the evidence for metastability of {gamma}-Fe at low temperatures below the {var_epsilon}-{gamma} phase boundary.

  16. A compact bellows-driven diamond anvil cell for high-pressure, low-temperature magnetic measurements

    NASA Astrophysics Data System (ADS)

    Feng, Yejun; Silevitch, D. M.; Rosenbaum, T. F.

    2014-03-01

    We present the design of an efficient bellows-controlled diamond anvil cell that is optimized for use inside the bores of high-field superconducting magnets in helium-3 cryostats, dilution refrigerators, and commercial physical property measurement systems. Design of this non-magnetic pressure cell focuses on in situ pressure tuning and measurement by means of a helium-filled bellows actuator and fiber-coupled ruby fluorescence spectroscopy, respectively. We demonstrate the utility of this pressure cell with ac susceptibility measurements of superconducting, ferromagnetic, and antiferromagnetic phase transitions to pressures exceeding 8 GPa. This cell provides an opportunity to probe charge and magnetic order continuously and with high resolution in the three-dimensional Magnetic Field-Pressure-Temperature parameter space.

  17. Chronic Inflammation: Synergistic Interactions of Recruiting Macrophages (TAMs) and Eosinophils (Eos) with Host Mast Cells (MCs) and Tumorigenesis in CALTs. M-CSF, Suitable Biomarker for Cancer Diagnosis!

    PubMed Central

    Khatami, Mahin

    2014-01-01

    Ongoing debates, misunderstandings and controversies on the role of inflammation in cancer have been extremely costly for taxpayers and cancer patients for over four decades. A reason for repeated failed clinical trials (90% ± 5 failure rates) is heavy investment on numerous genetic mutations (molecular false-flags) in the chaotic molecular landscape of site-specific cancers which are used for “targeted” therapies or “personalized” medicine. Recently, unresolved/chronic inflammation was defined as loss of balance between two tightly regulated and biologically opposing arms of acute inflammation (“Yin”–“Yang” or immune surveillance). Chronic inflammation could differentially erode architectural integrities in host immune-privileged or immune-responsive tissues as a common denominator in initiation and progression of nearly all age-associated neurodegenerative and autoimmune diseases and/or cancer. Analyses of data on our “accidental” discoveries in 1980s on models of acute and chronic inflammatory diseases in conjunctival-associated lymphoid tissues (CALTs) demonstrated at least three stages of interactions between resident (host) and recruited immune cells: (a), acute phase; activation of mast cells (MCs), IgE Abs, histamine and prostaglandin synthesis; (b), intermediate phase; down-regulation phenomenon, exhausted/degranulated MCs, heavy eosinophils (Eos) infiltrations into epithelia and goblet cells (GCs), tissue hypertrophy and neovascularization; and (c), chronic phase; induction of lymphoid hyperplasia, activated macrophages (Mϕs), increased (irregular size) B and plasma cells, loss of integrity of lymphoid tissue capsular membrane, presence of histiocytes, follicular and germinal center formation, increased ratios of local IgG1/IgG2, epithelial thickening (growth) and/or thinning (necrosis) and angiogenesis. Results are suggestive of first evidence for direct association between inflammation and identifiable phases of immune

  18. Chronic Inflammation: Synergistic Interactions of Recruiting Macrophages (TAMs) and Eosinophils (Eos) with Host Mast Cells (MCs) and Tumorigenesis in CALTs. M-CSF, Suitable Biomarker for Cancer Diagnosis!

    PubMed

    Khatami, Mahin

    2014-01-27

    Ongoing debates, misunderstandings and controversies on the role of inflammation in cancer have been extremely costly for taxpayers and cancer patients for over four decades. A reason for repeated failed clinical trials (90% ± 5 failure rates) is heavy investment on numerous genetic mutations (molecular false-flags) in the chaotic molecular landscape of site-specific cancers which are used for "targeted" therapies or "personalized" medicine. Recently, unresolved/chronic inflammation was defined as loss of balance between two tightly regulated and biologically opposing arms of acute inflammation ("Yin"-"Yang" or immune surveillance). Chronic inflammation could differentially erode architectural integrities in host immune-privileged or immune-responsive tissues as a common denominator in initiation and progression of nearly all age-associated neurodegenerative and autoimmune diseases and/or cancer. Analyses of data on our "accidental" discoveries in 1980s on models of acute and chronic inflammatory diseases in conjunctival-associated lymphoid tissues (CALTs) demonstrated at least three stages of interactions between resident (host) and recruited immune cells: (a), acute phase; activation of mast cells (MCs), IgE Abs, histamine and prostaglandin synthesis; (b), intermediate phase; down-regulation phenomenon, exhausted/degranulated MCs, heavy eosinophils (Eos) infiltrations into epithelia and goblet cells (GCs), tissue hypertrophy and neovascularization; and (c), chronic phase; induction of lymphoid hyperplasia, activated macrophages (Mfs), increased (irregular size) B and plasma cells, loss of integrity of lymphoid tissue capsular membrane, presence of histiocytes, follicular and germinal center formation, increased ratios of local IgG1/IgG2, epithelial thickening (growth) and/or thinning (necrosis) and angiogenesis. Results are suggestive of first evidence for direct association between inflammation and identifiable phases of immune dysfunction in the direction of

  19. Melting temperature of water at high pressure measured in a laser-heated diamond anvil cell with CO2 laser

    NASA Astrophysics Data System (ADS)

    Kimura, T.; Kuwayama, Y.

    2012-12-01

    The phase relations and physical properties of water at high pressures and temperatures are important physical, geophysical, and planetary problems. For example, recent molecular dynamics calculations suggest that water is superionic at high densities relevant to planets such as Uranus and Neptune [1, 2], and this predicted property plays a key role in dynamo models to explain the unusual non-dipolar magnetic field structure of these planets [3, 4]. The advances in combining techniques such as synchrotron x-ray diffraction or in situ optical Raman spectroscopy with diamond anvil cell (DAC) technologies allow us to measure the melting temperature of water to within a few percent for pressures up to 20 GPa [5-8]. However, at pressures above 20 GPa, recently reported values of melting temperature exhibit significant differences with each other [7-10]. This discrepancy should be caused by a chemical reaction occurred between the metal absorber contained in the DAC and the dissociated water. By using CO2 laser for sample heating, the metal is not necessary because water has significant absorption in the wavelength range of CO2 laser (10.6 μm). We report the melting temperature of water in a diamond anvil cell more than 20 GPa using CO2 laser heating system. References [1] M. French et al., Phys. Rev. B 79, 054107 (2009). [2] M. French et al., Phys. Rev. B 82, 174108 (2010). [3] S. Stanley and J. Bloxham, Nature 428, 151 (2004). [4] R. Redmer et al., Icarus 211, 798 (2011). [5] F. Datch et al., Phys. Rev. B 61, 6335 (2000). [6] JF. Lin et al., J. Chem. Phys 121, 8423 (2004). [7] JF. Lin et al., Geophys. Res. Lett. 32, L11306 (2005). [8] AF. Goncharov et al., Phys. Rev. Lett. 94, 125504 (2005). [9] B. Schwager et al., J. Phys. Condens. Matter 16, 51177 (2004). [10] AF. Goncharov et al., J. Chem. Phys. 130, 124514 (2009).

  20. Phase relations of iron up to 280 GPa and 3700 K: a diamond-anvil cell study

    NASA Astrophysics Data System (ADS)

    Tateno, S.; Hirose, K.; Sata, N.; Ohishi, Y.

    2009-12-01

    The Earth’s core is mainly composed of iron. Thus the crystal structure of iron is of prime importance for understanding the nature of solid inner core. Although the phase relations of iron have been extensively studied by shock wave, static compression, and theoretical calculation, the results are still controversial. In particular, limited pressure and temperature (P-T) range accessible by static diamond-anvil cell (DAC) technique has made it difficult to solve the problem. Here we examined the phase relations of pure iron on the basis of synchrotron X-ray diffraction measurement in situ at high P-T in a laser-heated DAC. We extended the accessible P-T conditions employed by the newly developed flat top double-sided laser heating system using fiber lasers at BL10XU of SPring-8. Pure iron powder was used as a starting material, which was embedded between SiO2 glass for thermal insulation. The results show that iron is stable with hexagonal close-packed structure (hcp) in the entire experimental PT range of 200-280 GPa and 2000-4300 K. Body-centered cubic (bcc) phase of iron was not observed above 225 GPa and 3400 K, where Dubrovinsky et al. (2007) confirmed the phase transition in iron-nickel alloy from hcp to bcc structure. We further found serious carbon contamination from diamond anvils during laser heating above 3000 K as evidenced by the X-ray diffraction peaks from Fe3C cementite. This problem calls for selecting the material adequate for insulating layers to avoid the carbon transportation.

  1. Finite element modeling of melting and fluid flow in the laser-heated diamond-anvil cell

    NASA Astrophysics Data System (ADS)

    Gomez-Perez, N.; Rodriguez, J. F.; McWilliams, R. S.

    2017-04-01

    The laser-heated diamond anvil cell is widely used in the laboratory study of materials behavior at high-pressure and high-temperature, including melting curves and liquid properties at extreme conditions. Laser heating in the diamond cell has long been associated with fluid-like motion in samples, which is routinely used to determine melting points and is often described as convective in appearance. However, the flow behavior of this system is poorly understood. A quantitative treatment of melting and flow in the laser-heated diamond anvil cell is developed here to physically relate experimental motion to properties of interest, including melting points and viscosity. Numerical finite-element models are used to characterize the temperature distribution, melting, buoyancy, and resulting natural convection in samples. We find that continuous fluid motion in experiments can be explained most readily by natural convection. Fluid velocities, peaking near values of microns per second for plausible viscosities, are sufficiently fast to be detected experimentally, lending support to the use of convective motion as a criterion for melting. Convection depends on the physical properties of the melt and the sample geometry and is too sluggish to detect for viscosities significantly above that of water at ambient conditions, implying an upper bound on the melt viscosity of about 1 mPa s when convective motion is detected. A simple analytical relationship between melt viscosity and velocity suggests that direct viscosity measurements can be made from flow speeds, given the basic thermodynamic and geometric parameters of samples are known.

  2. The African Connection

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2012-01-01

    From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

  3. The African Connection

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2012-01-01

    From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

  4. Contrasting a non-developing African mesoscale convective system with the precursor to Hurricane Helene (2006)

    NASA Astrophysics Data System (ADS)

    Rivera, G.; Fuentes, J. D.; Evans, J. L.; Hamilton, H. L.

    2015-12-01

    Mesoscale convective systems (MCSs) in West Africa traverse strong thermodynamic gradients during their westward propagation from land to ocean. Some of the systems continue to develop after crossing the coastline and may ultimately develop into tropical cyclones, while others do not. Understanding the lifecycle behavior of these convective systems and the factors that contribute to their continuous development as they transition from a continental environment to a marine environment poses a challenge. We examine the difference between two MCSs, one that continued to develop when it crossed the West African coast and one that did not, using European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA Interim) and Tropical Rainfall Measurement Mission (TRMM) 3B42 data. The non-developing MCS that intensified briefly while over land, weakened as soon as it crossed the coast. Preliminary results show that the developing MCS interacted with two cyclonic vortices, one associated with an African Easterly Wave that was propagating towards the coast and the other vortex generated by the topography near the coast.

  5. Simplified manual fabrication of cubic-zirconia gem anvils for extended energy-range spectroscopic studies to routine high pressures of 100-150 kbar (10-15 GPa)

    NASA Astrophysics Data System (ADS)

    Jackson, N. R.; Erasmus, R. M.; Hearne, G. R.

    2010-07-01

    Methodology has been developed so as to attain routine extreme conditions as high as 10-15 GPa in a gem anvil optical pressure cell using hand (manual) processed gem anvils. The anvils polished by a simplified hand held tool are inexpensive single crystal cubic zirconia (CZ) gems that have various optical advantages over diamond anvils. Appreciable pressures are attained with culet and corresponding sample cavity dimensions that are relatively convenient to load with sample material. Some technical details are provided as regards the simplified manual fabrication process, thus emphasizing the relative ease and cost effectiveness of the hand polishing technique for fabricating such high pressure anvils. Raman spectroscopy measurements, in triple subtractive mode with a confocal pinhole geometry, are used to exemplify the usefulness of the CZ gem anvil cell methodology in pressure tuning experiments. This is particularly convenient for conventional low wave-number (lattice mode regime) Raman high pressure studies, which have not been reported previously in this context. Various other applications of such anvils are suggested.

  6. BOLIVAR and GULFREX MCS Data Constrain Closure of the Grenada Backarc Basin During Oblique Collision Between the Lesser Antilles Arc System and Northern South America

    NASA Astrophysics Data System (ADS)

    Aitken, T. J.; Mann, P.; Christeson, G.

    2004-12-01

    The Lesser Antilles evolved from the mid-Cretaceous as an extensional arc system formed above a steeply dipping slab of Atlantic oceanic crust. The arc became extensional during the Paleocene - early Eocene along normal faults at the eastern edge of the basin as the present-day Lesser Antilles chain rifted away from the Aves Ridge. Backarc rifting ceased during the early Eocene, leaving the 140 km wide 3 km deep Grenada backarc basin. Sediment accumulation reached nearly 8 km during the Paleogene with another 1.5 km of sediments accumulating during the Neogene. In this presentation, we combine newly acquired MCS lines from the BOLIVAR study with existing GULFREX data collected in 1975 to document the structural and stratigraphic effects of closure of the Grenada backarc basin because of the progressive, oblique collision between the Lesser Antilles arc system and northern South America. The southern end of the Grenada basin has been narrowed from an undeformed width of approximately 100 km to a deformed width of 30 km, and rotated nearly 90 degrees to the west as the arc system obliquely collides with the South American margin. Shortening of the colliding backarc basin is mainly accommodated by inversion of Paleogene normal faults on the eastern edge of the basin, folding, low-angle thrust faults, and possibly shale diapirism. We propose that this closure in the area is a backthrusting response during Oligocene - late Miocene closure along the leading edge of the oblique arc-continent collision in the Eastern Venezuelan basin.

  7. Characterizing the admixed African ancestry of African Americans.

    PubMed

    Zakharia, Fouad; Basu, Analabha; Absher, Devin; Assimes, Themistocles L; Go, Alan S; Hlatky, Mark A; Iribarren, Carlos; Knowles, Joshua W; Li, Jun; Narasimhan, Balasubramanian; Sidney, Steven; Southwick, Audrey; Myers, Richard M; Quertermous, Thomas; Risch, Neil; Tang, Hua

    2009-01-01

    Accurate, high-throughput genotyping allows the fine characterization of genetic ancestry. Here we applied recently developed statistical and computational techniques to the question of African ancestry in African Americans by using data on more than 450,000 single-nucleotide polymorphisms (SNPs) genotyped in 94 Africans of diverse geographic origins included in the HGDP, as well as 136 African Americans and 38 European Americans participating in the Atherosclerotic Disease Vascular Function and Genetic Epidemiology (ADVANCE) study. To focus on African ancestry, we reduced the data to include only those genotypes in each African American determined statistically to be African in origin. From cluster analysis, we found that all the African Americans are admixed in their African components of ancestry, with the majority contributions being from West and West-Central Africa, and only modest variation in these African-ancestry proportions among individuals. Furthermore, by principal components analysis, we found little evidence of genetic structure within the African component of ancestry in African Americans. These results are consistent with historic mating patterns among African Americans that are largely uncorrelated to African ancestral origins, and they cast doubt on the general utility of mtDNA or Y-chromosome markers alone to delineate the full African ancestry of African Americans. Our results also indicate that the genetic architecture of African Americans is distinct from that of Africans, and that the greatest source of potential genetic stratification bias in case-control studies of African Americans derives from the proportion of European ancestry.

  8. Simultaneous Determination of Elastic and Structural Properties Under Simulated Mantle Conditions Using Multi-Anvil Device MAX80

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Schilling, F. R.; Lathe, C.

    2003-12-01

    The resolution and amount of seismic data from the Earth's deep interior increased dramatically during the last few years. To improve our understanding of Earth's deep interior, the interpretation of these data requires measurements of elastic properties of Earth materials under simulated mantle conditions, simultaneously at high pressure and temperature conditions,. We use ultrasonic interferometry to measure travel time with high precision, on samples enclosed in a high-pressure multi-anvil device (MAX80). In addition to travel times the determination of wave velocities requires the knowledge of the exact sample length under in situ conditions. Nowadays, two possibilities are used - scanning the interfaces of the sample (Mueller et al., 2003) and X-radiography (Li et al., 2001). Besides elastic properties structural characteristics are investigated at the same time. To determine travel time, the classical digital sweep interferometry is used, which is very time consuming. For example a 60 MHz frequency sweep with 100 kHz steps lasts for more than 30 minutes. Therefore, a single measurement of Vp and Vs requires more than 1 hour. This is a serious limitation for measurements under transient conditions and limits the data collection at elevated temperatures. To avoid this, an ultrasonic transfer function technique (UTF) was installed, related to the technique described by Li et al. (2002), which allows the generation and emission of all the frequencies simultaneously (Mueller et al., 2003). The "GFZ" type UTF technique allows to consider the characteristics of the transducer-glue-anvil combination (Mueller et al., 2003) and to determine Vp and Vs within less than 2 minutes. Some results on non-quenchable phase transitions will be given to discuss the different interferometric techniques. The precision of sample length determination by X-radiography will be compared to the scanning of the interface technique. Li, B.; Vaughan, M.T.; Kung, J.; Weidner, D.J., NSLS

  9. Extensive MRO CRISM Observations of 1.27 micron O2 Airglow in Mars Polar Night and Their Comparison to MRO MCS Temperature Profiles and LMD GCM Simulations

    NASA Technical Reports Server (NTRS)

    Clancy, R. Todd; Sandor, Brad J.; Wolff, Michael J.; Smith, Michael Doyle; Lefevre, Franck; Madeleine, Jean-Baptiste; Forget, Francois; Murchie, Scott L.; Seelos, Frank P.; Seelos, Kim D.; Nair, Hari A.; Toigo, Anthony D.; Humm, David; Kass, David M.; Kleinbahl, Armin; Heavens, Nicholas

    2012-01-01

    The Martian polar night distribution of 1.27 micron (0-0) band emission from O2 singlet delta [O2(1Delta(sub g))] is determined from an extensive set of Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectral Mapping (CRISM) limb scans observed over a wide range of Mars seasons, high latitudes, local times, and longitudes between 2009 and 2011. This polar nightglow reflects meridional transport and winter polar descent of atomic oxygen produced from CO2 photodissociation. A distinct peak in 1.27 micron nightglow appears prominently over 70-90NS latitudes at 40-60 km altitudes, as retrieved for over 100 vertical profiles of O2(1Delta(sub g)) 1.27 micron volume emission rates (VER). We also present the first detection of much (x80+/-20) weaker 1.58 micron (0-1) band emission from Mars O2(1Delta(sub g)). Co-located polar night CRISM O2(1Delta(sub g)) and Mars Climate Sounder (MCS) (McCleese et al., 2008) temperature profiles are compared to the same profiles as simulated by the Laboratoire de Météorologie Dynamique (LMD) general circulation/photochemical model (e.g., Lefèvre et al., 2004). Both standard and interactive aerosol LMD simulations (Madeleine et al., 2011a) underproduce CRISM O2(1Delta(sub g)) total emission rates by 40%, due to inadequate transport of atomic oxygen to the winter polar emission regions. Incorporation of interactive cloud radiative forcing on the global circulation leads to distinct but insufficient improvements in modeled polar O2(1Delta(sub g)) and temperatures. The observed and modeled anti-correlations between temperatures and 1.27 mm band VER reflect the temperature dependence of the rate coefficient for O2(1Delta(sub g)) formation, as provided in Roble (1995).

  10. Effect of Shear Strain on the α-ε Phase Transition of Iron: a New Approach in the Rotational Diamond Anvil Cell

    SciTech Connect

    Ma,Y.; Selvi, E.; Levitas, V.; Hashemi, J.

    2006-01-01

    The effect of shear strain on the iron {alpha}-{var_epsilon} phase transformation has been studied using a rotational diamond anvil cell (RDAC). The initial transition is observed to take place at the reduced pressure of 10.8 GPa under pressure and shear operation. Complete phase transformation was observed at 15.4 GPa. The rotation of an anvil causes limited pressure elevation and makes the pressure distribution symmetric in the sample chamber before the phase transition. However, it causes a significant pressure increase at the center of the sample and brings about a large pressure gradient during the phase transformation. The resistance to the phase interface motion is enhanced due to strain hardening during the pressure and shear operations on iron and this further increases the transition pressure. The work of macroscopic shear stress and the work of the pressure and shear stress at the defect tips account for the pressure reduction of the iron phase transition.

  11. African and Non-African Admixture Components in African Americans and An African Caribbean Population

    PubMed Central

    Murray, Tanda; Beaty, Terri H.; Mathias, Rasika A.; Rafaels, Nicholas; Grant, Audrey Virginia; Faruque, Mezbah U.; Watson, Harold R.; Ruczinski, Ingo; Dunston, Georgia M.; Barnes, Kathleen C.

    2013-01-01

    Admixture is a potential source of confounding in genetic association studies, so it becomes important to detect and estimate admixture in a sample of unrelated individuals. Populations of African descent in the US and the Caribbean share similar historical backgrounds but the distributions of African admixture may differ. We selected 416 ancestry informative markers (AIMs) to estimate and compare admixture proportions using STRUCTURE in 906 unrelated African Americans (AAs) and 294 Barbadians (ACs) from a study of asthma. This analysis showed AAs on average were 72.5% African, 19.6% European and 8% Asian, while ACs were 77.4% African, 15.9% European, and 6.7% Asian which were significantly different. A principal components analysis based on these AIMs yielded one primary eigenvector that explained 54.04% of the variation and captured a gradient from West African to European admixture. This principal component was highly correlated with African vs. European ancestry as estimated by STRUCTURE (r2 = 0.992, r2 = 0.912, respectively). To investigate other African contributions to African American and Barbadian admixture, we performed PCA on ~14,000 (14k) genome-wide SNPs in AAs, ACs, Yorubans, Luhya and Maasai African groups, and estimated genetic distances (FST). We found AAs and ACs were closest genetically (FST = 0.008), and both were closer to the Yorubans than the other East African populations. In our sample of individuals of African descent, ~400 well-defined AIMs were just as good for detecting substructure as ~14,000 random SNPs drawn from a genome-wide panel of markers. PMID:20717976

  12. African and non-African admixture components in African Americans and an African Caribbean population.

    PubMed

    Murray, Tanda; Beaty, Terri H; Mathias, Rasika A; Rafaels, Nicholas; Grant, Audrey Virginia; Faruque, Mezbah U; Watson, Harold R; Ruczinski, Ingo; Dunston, Georgia M; Barnes, Kathleen C

    2010-09-01

    Admixture is a potential source of confounding in genetic association studies, so it becomes important to detect and estimate admixture in a sample of unrelated individuals. Populations of African descent in the US and the Caribbean share similar historical backgrounds but the distributions of African admixture may differ. We selected 416 ancestry informative markers (AIMs) to estimate and compare admixture proportions using STRUCTURE in 906 unrelated African Americans (AAs) and 294 Barbadians (ACs) from a study of asthma. This analysis showed AAs on average were 72.5% African, 19.6% European and 8% Asian, while ACs were 77.4% African, 15.9% European, and 6.7% Asian which were significantly different. A principal components analysis based on these AIMs yielded one primary eigenvector that explained 54.04% of the variation and captured a gradient from West African to European admixture. This principal component was highly correlated with African vs. European ancestry as estimated by STRUCTURE (r(2)=0.992, r(2)=0.912, respectively). To investigate other African contributions to African American and Barbadian admixture, we performed PCA on approximately 14,000 (14k) genome-wide SNPs in AAs, ACs, Yorubans, Luhya and Maasai African groups, and estimated genetic distances (F(ST)). We found AAs and ACs were closest genetically (F(ST)=0.008), and both were closer to the Yorubans than the other East African populations. In our sample of individuals of African descent, approximately 400 well-defined AIMs were just as good for detecting substructure as approximately 14,000 random SNPs drawn from a genome-wide panel of markers. (c) 2010 Wiley-Liss, Inc.

  13. Experimental Investigation of Magnetic Superconducting and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures using Designer Diamond Anvils

    SciTech Connect

    Maple, M. Brian; Jeffries, Jason R.; Ho, Pei-Chun; Butch, Nicholas P.

    2004-09-01

    Pressure is often used as a controlled parameter for the investigation of condensed matter systems. In particular, pressure experiments can provide valuable information into the nature of superconductivity, magnetism, and the coexistence of these two phenomena. Some f-electron, heavy-fermion materials display interesting and novel behavior at moderately low pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require ultrahigh pressure techniques, techniques that generate significantly higher pressures than conventional methods, to sufficiently explore their important properties. To that end, we have been funded to develop an ultrahigh pressure diamond anvil cell facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena. Our goals for the first year of this grant were as follows: (a) set up and test a suitable refrigerator; (b) set up a laser and spectrometer fluorescence system to determine the pressure within the diamond anvil cell; (c) perform initial resistivity measurements at moderate pressures from room temperature to liquid helium temperatures ({approx}1K); (d) investigate f-electron materials within our current pressure capabilities to find candidate materials for high-pressure studies. During the past year, we have ordered almost all the components required to set up a diamond anvil cell facility at UCSD, we have received and implemented many of the components that have been ordered, we have performed low pressure research on several materials, and we have engaged in a collaborative effort with Sam Weir at Lawrence Livermore National Lab (LLNL) to investigate Au4V under ultrahigh pressure in a designer diamond anvil cell (dDAC). This report serves to highlight the progress we have made towards developing an ultrahigh pressure research facility at UCSD, the research performed in the past year

  14. The African superswell

    NASA Technical Reports Server (NTRS)

    Nyblade, Andrew A.; Robinson, Scott W.

    1994-01-01

    Maps of residual bathymetry in the ocean basins around the African continent reveal a broad bathymetric swell in the southeastern Atlantic Ocean with an amplitude of about 500 m. We propose that this region of anomalously shallow bathymetry, together with the contiguous eastern and southern African plateaus, form a superswell which we refer to as the African superswell. The origin of the African superswell is uncertain. However, rifting and volcanism in eastern Africa, as well as heat flow measurements in southern Africa and the southeastern Atlantic Ocean, suggest that the superswell may be attributed, at least in part, to heating of the lithosphere.

  15. A new diamond anvil cell for hydrothermal studies to 2.5 GPa and from -190 to 1200 °C

    USGS Publications Warehouse

    Bassett, William A.; Shen, A.H.; Bucknum, M.; Chou, I.-Ming

    1993-01-01

    A new style of diamond anvil cell(DAC) has been designed and built for conducting research in fluids at pressures to 2.5 GPa and temperatures from −190 to 1200 °C. The new DAC has been used for optical microscope observations and synchrotron x‐ray diffraction studies. Fringes produced by interference of laser light reflected from top and bottom anvil faces and from top and bottom sample faces provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in samples that have resulted from transitions and reactions. X‐ray diffraction patterns of samples under hydrothermal conditions have been made by the energy dispersive method using synchrotron radiation. The new DAC has individual heaters and individual thermocouples for the upper and lower anvils that can be controlled and can maintain temperatures with an accuracy of ±0.5 °C. Low temperatures are achieved by introducing liquid nitrogen directly into the DAC. The equation of state of H2O and the α‐β quartz transition are used to determine pressure with an accuracy of ±1% in the aqueous samples. The new DAC has been used to redetermine five isochores of H2O as well as the dehydration curves of brucite, Mg(OH)2, and muscovite, KAl2(Si3Al)O10(OH)2.

  16. Pressure estimation using the ‘diamond Raman scale’ at low pressures in diamond anvil cell experiments using a highly confocal Raman system

    NASA Astrophysics Data System (ADS)

    Fujii, Taku; Ohfuji, Hiroaki

    2015-02-01

    Pressure estimation using the frequency shift of the diamond Raman peak from the anvil culet is readily and widely used in diamond anvil cell experiments along with the conventional ruby fluorescence method. Here, we propose a modified diamond Raman scale particularly designed for pressure measurement below ~10 GPa. A series of experiments were conducted using a highly confocal Raman system and H2O, ethanol/methanol mixture and NaCl samples loaded in a rhenium gasket which was pre-indented to 40-60 or 100-110 μm thick. The result showed that the frequency of the diamond Raman peak from the anvil culet increases linearly with pressure between 1 and 13 GPa, when using a sufficiently pre-indented (40-60 μm thick) gasket. The frequency shifts are calibrated against the pressure determined by the ruby fluorescence method, which is an alternative pressure scale. In addition, a preliminary measurement at high temperature up to 575 K suggests the potential application of this method for high temperature experiments.

  17. Sapphire-anvil cell for small-angle neutron scattering measurements in large-volume liquid samples up to 530 MPa

    NASA Astrophysics Data System (ADS)

    Bonetti, M.; Calmettes, P.

    2005-04-01

    A cell with unsupported beveled sapphire-anvils was developed to carry out small-angle neutron scattering measurements in large-volume liquid samples up to a pressure of 530 MPa. The body of the anvil is a cylinder with a 30 mm diameter. One end is shaped into a truncated cone with a face 14 mm in diameter. The two opposed anvils squeeze a flat metallic gasket of thickness between 1 and 3 mm with a central hole between 4 and 10 mm in diameter. The initial sample volume varies from about 10 to 240mm3. The highest achievable pressure depends on the dimensions and on the mechanical properties of the gasket. To allow a high neutron transmission of the collimated neutron beam, a 10-mm-diam bore is machined along the cell axis. For a neutron beam of 7 mm in diameter, the maximum forward scattering angle is about 9.5°. With a neutron wavelength of 0.4 nm, this allows scattering spectra to be recorded for wave-number transfers up to 2.6nm-1.

  18. Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments.

    PubMed

    Sano-Furukawa, A; Hattori, T; Arima, H; Yamada, A; Tabata, S; Kondo, M; Nakamura, A; Kagi, H; Yagi, T

    2014-11-01

    We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm(3). Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

  19. Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

    SciTech Connect

    Zaug, J.M.

    1997-07-01

    An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

  20. Hierarchical multiscale framework for materials modeling: Equation of state implementation and application to a Taylor anvil impact test of RDX

    NASA Astrophysics Data System (ADS)

    Barnes, Brian C.; Spear, Carrie E.; Leiter, Ken W.; Becker, Richard; Knap, Jaroslaw; Lísal, Martin; Brennan, John K.

    2017-01-01

    In order to progress towards a materials-by-design capability, we present work on a challenge in continuum-scale modeling: the direct incorporation of complex physical processes in the constitutive evaluation. In this work, we use an adaptive scale-bridging computational framework executing in parallel in a heterogeneous computational environment to couple a fine-scale, particle-based model computing the equation of state (EOS) to the constitutive response in a finite-element multi-physics simulation. The EOS is obtained from high fidelity materials simulations performed via dissipative particle dynamics (DPD) methods. This scale-bridging framework is progress towards an innovation infrastructure that will be of great utility for systems in which essential aspects of material response are too complex to capture by closed form material models. The design, implementation, and performance of the scale-bridging framework are discussed. Also presented is a proof-of-concept Taylor anvil impact test of non-reacting 1,3,5-trinitrohexahydro-s-triazine (RDX).

  1. The effect of pressure on the kinetics of γ-anhydrite crystallization investigated by diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Liu, Chuanjiang; Zheng, Haifei; Du, Jianguo; Wang, Duojun

    2015-01-01

    The crystallization kinetics of γ-anhydrite was investigated in the temperature and pressure ranges of 373-473 K and 1094-1903 MPa using a hydrothermal diamond anvil cell (HDAC) and Raman spectroscopy. A calcium sulfate solution was formed by dissolving gypsum in water at high pressure, and γ-anhydrite crystallized due to the increasing temperature. The relationship among the reaction rate, k, the temperature, T, and the pressure, P was established as k=-1.75×10-3+1.83×10-6P+3.57×10-7T, with an R2 value of 0.943, of which the applicable range is 373 K≤T≤473 K and 1196 MPa≤P≤1903 MPa. An elevation of T or P will accelerate the crystallization rate of γ-anhydrite. The time exponent n obtained between 0.96 and 1.29 indicates that the process of crystallization should be controlled by instant nucleation on the grain boundary and diffusion controlled growth. In the process of crystallization, the volume is reduced because of the decrease of pressure, and the volume change ΔV is equal to -6.05×10-6 m3/mol. The calculated activation energy Ea is 10.7 kJ/mol, and the pre-exponential factor A is 2.27×10-2 s-1.

  2. Non-hydrostatic behavior of KBr as a pressure medium in diamond anvil cells up to 5.63 GPa.

    PubMed

    Zhao, Jing; Ross, Nancy L

    2015-05-13

    Non-hydrostatic stresses of KBr acting as a pressure-transmitting medium have been investigated by examining their effect on a single crystal of quartz in a diamond anvil cell (DAC). The lattice strains or distortions were measured by single-crystal x-ray diffraction methods, and the non-hydrostatic deviatoric stresses for KBr were determined up to 5.63(2) GPa. The experimental results show that differences between axial stress components in the direction normal to the DAC culet face and the radial stress components in directions parallel to the DAC culet face are about 0.063(24) GPa at pressures below 2.14 GPa, and the pressure-transmitting medium can therefore be considered as quasi-hydrostatic up to this pressure. However above 2.14 GPa, after the phase transition pressure of KBr during which it converts from the B1 phase to the B2 phase, the deviatoric stresses constantly increase with increasing pressure. At the maximum pressure of this study, 5.63(2) GPa, the difference between axial stress and radial stress components reaches 0.93(9) GPa. Different variations in the non-hydrostatic deviatoric stresses were observed during both compression and decompression of the DAC, and are mainly ascribed to the phase-transition-induced volume change of KBr.

  3. Pressurizing Field-Effect Transistors of Few-Layer MoS2 in a Diamond Anvil Cell

    SciTech Connect

    Chen, Yabin; Ke, Feng; Ci, Penghong; Ko, Changhyun; Park, Taegyun; Saremi, Sahar; Liu, Huili; Lee, Yeonbae; Suh, Joonki; Martin, Lane W.; Ager, Joel W.; Chen, Bin; Wu, Junqiao

    2016-12-08

    Hydrostatic pressure applied using diamond anvil cells (DAC) has been widely explored to modulate physical properties of materials by tuning their lattice degree of freedom. Independently, electrical field is able to tune the electronic degree of freedom of functional materials via, for example, the field-effect transistor (FET) configuration. Combining these two orthogonal approaches would allow discovery of new physical properties and phases going beyond the known phase space. Such experiments are, however, technically challenging and have not been demonstrated. In this paper, we report a feasible strategy to prepare and measure FETs in a DAC by lithographically patterning the nanodevices onto the diamond culet. Multiple-terminal FETs were fabricated in the DAC using few-layer MoS2 and BN as the channel semiconductor and dielectric layer, respectively. It is found that the mobility, conductance, carrier concentration, and contact conductance of MoS2 can all be significantly enhanced with pressure. Finally, we expect that the approach could enable unprecedented ways to explore new phases and properties of materials under coupled mechano-electrostatic modulation.

  4. Appropriate pressure-transmitting media for cryogenic experiment in the diamond anvil cell up to 10 GPa

    NASA Astrophysics Data System (ADS)

    Tateiwa, Naoyuki; Haga, Yoshinori

    2010-03-01

    We evaluated the qualities of pressure-transmitting media by the ruby fluorescence method at room temperature, 77 and 4.2 K in the diamond anvil cell (DAC) up to 10 GPa in order to find appropriate media for the low temperature experiment. Investigations were done on fourteen kinds of media: a 1:1 mixture by volume of Fluorinert FC-70 and FC-77, Daphne 7373 and 7474, NaCl, silicon oil (polydimethylsiloxane), vaselin, 2-propanol, glycerin, a 1:1 mixture by volume of n-pentane and isopentane, a 4:1 mixture by volume of methanol and ethanol, petroleum ether, nitrogen, argon and helium. We discuss the non-hydrostatic effects of the pressure in the media from the broadening effect of the ruby R1 fluorescence line. At the low temperature region, the non-hydrostatic effects develop continuously with increasing pressure from the low-pressure region in the all media. We reveal the relative strengths of the non-hydrostatic effects appeared in the media at 77K.

  5. Strategies for in situ laser heating in the diamond anvil cell at an X-ray diffraction beamline

    PubMed Central

    Petitgirard, Sylvain; Salamat, Ashkan; Beck, Pierre; Weck, Gunnar; Bouvier, Pierre

    2014-01-01

    An overview of several innovations regarding in situ laser-heating techniques in the diamond anvil cell at the high-pressure beamline ID27 of the European Synchrotron Radiation Facility is presented. Pyrometry measurements have been adapted to allow simultaneous double-sided temperature measurements with the installation of two additional online laser systems: a CO2 and a pulsed Nd:YAG laser system. This reiteration of laser-heating advancements at ID27 is designed to pave the way for a new generation of state-of-the-art experiments that demand the need for synchrotron diffraction techniques. Experimental examples are provided for each major development. The capabilities of the double pyrometer have been tested with the Nd:YAG continuous-wave lasers but also in a time-resolved configuration using the nanosecond-pulsed Nd:YAG laser on a Fe sample up to 180 GPa and 2900 K. The combination of time-resolved X-ray diffraction with in situ CO2 laser heating is shown with the crystallization of a high-pressure phase of the naturally found pyrite mineral MnS2 (11 GPa, 1100–1650 K). PMID:24365921

  6. XAFS measurements on zinc chloride aqueous solutions from ambient to supercritical conditions using the diamond anvil cell

    USGS Publications Warehouse

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    1999-01-01

    The structure and bonding properties of metal complexes in subcritical and supercritical fluids are still largely unknown. Conventional high pressure and temperature cell designs impose considerable limitations on the pressure, temperature, and concentration of metal salts required for measurements on solutions under supercritical conditions. In this study, we demonstrate the first application of the diamond anvil cell, specially designed for x-ray absorption studies of first-row transition metal ions in supercritical fluids. Zn K-edge XAFS spectra were measured from aqueous solutions of 1-2m ZnCl2 and up to 6m NaCl, at temperatures ranging from 25-660 ??C and pressures up to 800 MPa. Our results indicate that the ZnCl42- complex is predominant in the 1m ZnCl2/6m NaCl solution, while ZnCl2(H2O)2 is similarly predominant in the 2m ZnCl2 solution, at all temperatures and pressures. The Zn-Cl bond length of both types of chlorozinc(II) complexes was found to decrease at a rate of about 0.01 A??/100 ??C.

  7. Sea Level History in 3D: Early results of an ultra-high resolution MCS survey across IODP Expedition 313 drillsites

    NASA Astrophysics Data System (ADS)

    Mountain, G. S.; Kucuk, H. M.; Nedimovic, M. R.; Austin, J. A., Jr.; Fulthorpe, C.; Newton, A.; Baldwin, K.; Johnson, C.; Stanley, J. N.; Bhatnagar, T.

    2015-12-01

    Although globally averaged sea level is rising at roughly 3 mm/yr (and is accelerating), rates of local sea-level change measured at coastlines may differ from this number by a factor of two or more; at some locations, sea level may even be falling. This is due to local processes that can match or even reverse the global trend, making it clear that reliable predictions of future impacts of sea-level rise require a firm understanding of processes at the local level. The history of local sea-level change and shoreline response is contained in the geologic record of shallow-water sediments. We report on a continuing study of sea-level history in sediments at the New Jersey continental margin, where compaction and glacial isostatic adjustment are currently adding 2 mm/yr to the globally averaged rise. We collected 570 sq km of ultra-high resolution 3D MCS data aboard the R/V Langseth in June-July 2015; innovative recording and preliminary results are described by Nedimovic et al. in this same session. The goal was to provide regional context to coring and logging at IODP Exp 313 sites 27-29 that were drilled 750 m into the New Jersey shelf in 2009. These sites recovered a nearly continuous record of post-Eocene sediments from non-marine soils, estuaries, shoreface, delta front, pro-delta and open marine settings. Existing seismic data are good but are 2D high-resolution profiles at line spacings too wide to enable mapping of key nearshore features. The Langseth 3D survey used shallow towing of a tuned air gun array to preserve high frequencies, and twenty-four 50-m PCables each 12.5 apart provided 6.25 x 3.125 m common-midpoint bins along seventy-seven 50-km sail lines. With this especially dense spatial resolution of a pre-stack time migrated volume we expect to map rivers, incised valleys, barrier islands, inlets and bays, pro-delta clinoforms, tidal deltas, sequence boundaries, debris flow aprons, and more. Seismic attributes linked to sedimentary facies and

  8. The Neogene Forearc Basins of the Ecuadorian Shelf (1°N-2°20'S): Preliminary Interpretation of a Dense Grid of Mcs Data

    NASA Astrophysics Data System (ADS)

    Collot, J. Y.; Hernández Salazar, M. J.; Michaud, F.; Proust, J. N.; Ortega, R.; Aleman, A. M.

    2014-12-01

    Forearc basins serve as a sedimentary archive of sea-level variations and subduction-related tectonic processes. Along the Ecuadorian convergent margin (0°40'N-2°20'S) we interpreted a dense network (one profile every 4 km) of MCS reflection profiles acquired by the Ecuadorian State during the 2009 SCAN cruise with a 8-km-long, 640-channel streamer, and an array of 4000 in3total volume air guns to improve our understanding of the dynamic processes that shape forearc basin stratigraphy and tectonic structures. Isopach and structural maps of the acoustic basement show two structural segments on the margin. The northern segment (0°45'S-0°40'N) is characterized by - three sedimentary basins called Pedernales, Bahía-Jama and Caráquez basins, - N30°-50° trending transcurrent faults and -N80°-90° trending normal faults dipping to the south. The southern segment (2°S-0°45'S) is characterized by acoustic basement high, NS-trending until 1°10'S, with small localized sedimentary basins and by N320°-340° trending normal faults dipping to the north. At least five seismic units separated by unconformities are evidenced in the northern basins. Tentative correlations with geological data from the offshore Caraquez-1 well and the on-shore geology, suggest the following Neogene deformation steps: 1) sedimentary basins were initiated along N80°-90° trending normal faults in a regional N30°-50° trending strike slip system during lower Miocene; 2) deformation ended by a regional erosion (underlined by a flat regional unconformity) after the lower Miocene; 3) subsidence began by an undersea regional erosion after the Middle-Upper Miocene (underlined by an irregular regional unconformity), and 4) uplift and locally subsidence of the shelf edge with reactivation of a strike slip fault system from Pliocene (?) to Present. The arrival of the Carnegie ridge and associated seamounts to the trench axis is proposed at the origin of this last stage.

  9. Estimate of Precipitation from the Dual-Beam Airborne Radars in TOGA COARE. Part II: Precipitation Efficiency in the 9 February 1993 MCS.

    NASA Astrophysics Data System (ADS)

    Oury, Stéphane; Dou, Xiankang; Testud, Jacques

    2000-12-01

    Dual-beam airborne Doppler radars are commonly used in convection experiments for their ability to describe the dynamical structure of weather systems. However, instrumental limitations impose the use of wavelengths such as X-band, which are largely attenuated through heavy rain.This paper is the second of a series of two, which aim at developing schemes for attenuation correction. The authors' final objective is to improve the estimation of precipitation sampled from airborne radars. The first paper was dealing with the application of `differential algorithms' (`stereoradar' and `quad beam') to the independent retrieval of the specific attenuation and nonattenuated reflectivity, which shed some light on the physics of the precipitation. This second paper develops a more extensive procedure based upon the hybridization of a `differential' and an `integral' algorithm. It is much more flexible than the methods proposed in part one and allows full rainfall-rate retrievals in single aircraft experiments. This procedure is applied to the 9 February mesoscale convective system (MCS) study case from Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE), and the impact of the reflectivity correction on the water budget at the cloud system scale is discussed.As expected, the production of water in the 9 February squall line is maximum below the freezing level and is located in the updraft resulting from the interaction between the warm inflow and rear-to-front cold flow. The authors' analysis shows that the precipitation efficiency in the convective region of the system is 31%. Therefore, the large majority of water vapor condensed into cloud droplets and ice crystals does not immediately reach the surface as precipitation. It travels toward the rear of the system at the speed of the horizontal air motion, which suggests a large contribution of the stratiform area in the global water budget. The same calculation performed using raw

  10. African Literature as Celebration.

    ERIC Educational Resources Information Center

    Achebe, Chinua

    1989-01-01

    Describes the Igbo tradition of "Mbari," a communal creative enterprise that celebrates the world and the life lived in it through art. Contrasts the cooperative, social dimension of pre-colonial African culture with the exclusion and denial of European colonialism, and sees new African literature again celebrating human presence and…

  11. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  12. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

    This collection for children tells the stories of 16 African Americans who helped make America what it is today. African Americans can take pride in the heritage of these contributors to society. Biographies are given for the following: (1) Sojourner Truth, preacher and abolitionist; (2) Frederick Douglass, abolitionist; (3) Harriet Tubman, leader…

  13. Africans Away from Home.

    ERIC Educational Resources Information Center

    Clarke, John Henrik

    Africans who were brought across the Atlantic as slaves never fully adjusted to slavery or accepted its inevitability. Resistance began on board the slave ships, where many jumped overboard or committed suicide. African slaves in South America led the first revolts against tyranny in the New World. The first slave revolt in the Caribbean occurred…

  14. African Studies Computer Resources.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    African studies computer resources that are readily available in the United States with linkages to Africa are described, highlighting those most directly corresponding to African content. Africanists can use the following four fundamental computer systems: (1) Internet/Bitnet; (2) Fidonet; (3) Usenet; and (4) dial-up bulletin board services. The…

  15. African American Suicide

    MedlinePlus

    African American Suicide Fact Sheet Based on 2012 Data (2014) Overview • In 2012, 2,357 African Americans completed suicide in the U.S. Of these, 1,908 (80. ... rate of 9.23 per 100,000). The suicide rate for females was 1.99 per 100, ...

  16. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

    This collection for children tells the stories of 16 African Americans who helped make America what it is today. African Americans can take pride in the heritage of these contributors to society. Biographies are given for the following: (1) Sojourner Truth, preacher and abolitionist; (2) Frederick Douglass, abolitionist; (3) Harriet Tubman, leader…

  17. Understanding African American Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

    The purpose of this study was to assess the socialization skills, self-esteem, and academic readiness of African American males in a school environment. Discussions with students and the School Perceptions Questionnaire provided data for this investigation. The intended targets for this investigation were African American students; however, there…

  18. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  19. Educating African American Males

    ERIC Educational Resources Information Center

    Bell, Edward E.

    2010-01-01

    Background: Schools across America spend money, invest in programs, and sponsor workshops, offer teacher incentives, raise accountability standards, and even evoke the name of Obama in efforts to raise the academic achievement of African American males. Incarceration and college retention rates point to a dismal plight for many African American…

  20. African bees to control African elephants

    NASA Astrophysics Data System (ADS)

    Vollrath, Fritz; Douglas-Hamilton, Iain

    2002-11-01

    Numbers of elephants have declined in Africa and Asia over the past 30 years while numbers of humans have increased, both substantially. Friction between these two keystone species is reaching levels which are worryingly high from an ecological as well as a political viewpoint. Ways and means must be found to keep the two apart, at least in areas sensitive to each species' survival. The aggressive African bee might be one such method. Here we demonstrate that African bees deter elephants from damaging the vegetation and trees which house their hives. We argue that bees can be employed profitably to protect not only selected trees, but also selected areas, from elephant damage.

  1. Neotropical Africanized honey bees have African mitochondrial DNA.

    PubMed

    Smith, D R; Taylor, O R; Brown, W M

    1989-05-18

    Non-indigenous African honey bees have invaded most of South and Central America in just over 30 years. The genetic composition of this population and the means by which it rapidly colonizes new territory remain controversial. In particular, it has been unclear whether this 'Africanized' population has resulted from interbreeding between African and domestic European bees, or is an essentially pure African population. Also, it has not been known whether this population expanded primarily by female or by male migration. Restriction site mapping of 62 mitochondrial DNAs of African bees from Brazil, Venezuela and Mexico reveals that 97% were of African (Apis mellifera scutellata) type. Although neotropical European apiary populations are rapidly Africanized by mating with neotropical African males, there is little reciprocal gene flow to the neotropical African population through European females. These are the first genetic data to indicate that the neotropical African population could be expanding its range by female migration.

  2. A sensitive pressure sensor for diamond anvil cell experiments up to 2 GPa: FluoSpheres[reg

    SciTech Connect

    Picard, Aude; Oger, Phil M.; Daniel, Isabelle; Cardon, Herve; Montagnac, Gilles; Chervin, Jean-Claude

    2006-08-01

    We present an optical pressure sensor suitable for experiments in diamond anvil cell in the 0.1 MPa-2 GPa pressure range, for temperatures between ambient and 323 K. It is based on the pressure-dependent fluorescence spectrum of FluoSpheres[reg], which are commercially available fluorescent microspheres commonly used to measure blood flow in experimental biology. The fluorescence of microspheres is excited by the 514.5 nm line of an Ar{sup +} laser, and the resulting spectrum displays three very intense broad bands at 534, 558, and 598 nm, respectively. The reference wavelength and pressure gauge is that of the first inflection point of the spectrum, located at 525.6{+-}0.2 nm at ambient pressure. It is characterized by an instantaneous and large linear pressure shift of 9.93({+-}0.08) nm/GPa. The fluorescence of the FluoSpheres[reg] has been investigated as a function of pressure (0.1-4 GPa), temperature (295-343 K), pH (3-12), salinity, and pressure transmitting medium. These measurements show that, for pressures comprised between 0.1 MPa and 2 GPa, at temperatures not exceeding 323 K, at any pH, in aqueous pressure transmitting media, pressure can be calculated from the wavelength shift of two to three beads, according to the relation P=0.100 ({+-}0.001) {delta}{lambda}{sub i}(P) with {delta}{lambda}{sub i}(P)={lambda}{sub i}(P)-{lambda}{sub i}(0) and {lambda}{sub i}(P) as the wavelength of the first inflection point of the spectrum at the pressure P. This pressure sensor is approximately thirty times more sensitive than the ruby scale and responds instantaneously to pressure variations.

  3. A sensitive pressure sensor for diamond anvil cell experiments up to 2 GPa: FluoSpheres®

    NASA Astrophysics Data System (ADS)

    Picard, Aude; Oger, Phil M.; Daniel, Isabelle; Cardon, Hervé; Montagnac, Gilles; Chervin, Jean-Claude

    2006-08-01

    We present an optical pressure sensor suitable for experiments in diamond anvil cell in the 0.1MPa-2GPa pressure range, for temperatures between ambient and 323K. It is based on the pressure-dependent fluorescence spectrum of FluoSpheres®, which are commercially available fluorescent microspheres commonly used to measure blood flow in experimental biology. The fluorescence of microspheres is excited by the 514.5nm line of an Ar+ laser, and the resulting spectrum displays three very intense broad bands at 534, 558, and 598nm, respectively. The reference wavelength and pressure gauge is that of the first inflection point of the spectrum, located at 525.6±0.2nm at ambient pressure. It is characterized by an instantaneous and large linear pressure shift of 9.93(±0.08)nm/GPa. The fluorescence of the FluoSpheres® has been investigated as a function of pressure (0.1-4GPa), temperature (295-343K), pH (3-12), salinity, and pressure transmitting medium. These measurements show that, for pressures comprised between 0.1MPa and 2GPa, at temperatures not exceeding 323K, at any pH, in aqueous pressure transmitting media, pressure can be calculated from the wavelength shift of two to three beads, according to the relation P =0.100 (±0.001) Δλi(P ) with Δλi(P )=λi(P)-λi(0) and λi(P) as the wavelength of the first inflection point of the spectrum at the pressure P. This pressure sensor is approximately thirty times more sensitive than the ruby scale and responds instantaneously to pressure variations.

  4. Determination of differential stress in the D-DIA using cubic BN anvils and 2-D monochromatic diffraction

    NASA Astrophysics Data System (ADS)

    Uchida, T.; Wang, Y.; Rivers, M. L.; Durham, W. B.; Mei, S.

    2003-04-01

    We have adopted X-ray transparent cubic boron nitride (cBN) anvils in a modified deformation DIA (D-DIA) to conduct monochromatic diffraction using a 2-D CCD detector (SMART1500). This setup allows us to obtain real-time diffraction data with complete Debye rings that are essential for accurate determination of lattice strains in the deformed sample. Experiments have been conducted on MgO to 6.3 GPa and 1273 K in the D-DIA. Samples were deformed continuously up to 30 percent axial shortening, with various strain rates between 0.001 and 0.00001 per second, under fixed confining pressure. Pressure, temperature, sample length, and monochromatic diffraction patterns were recorded repeatedly during the constant-strain rate deformation process. A monochromatic beam with a wavelength of 0.248 Angstrom (50 keV) was used for diffraction. We have developed a software package to analyze the 2-D diffraction data. After spatial and flat-field corrections, each 2-D diffraction pattern is converted into a multiple of 1-D patterns, according to a given azimuth angle range (typically binned at 1 degree intervals). The 1-D patterns are then fitted to yield information on the azimuth dependence for each lattice spacing. Lattice strain is then computed based on the well-known theory (A.K. Singh, J. Appl. Phys., 73, 4278, 1993) to convert to differential stress. This approach allows us to examine lattice strain as a function of pressure, temperature, and total plastic strain systematically. With the known pressure and temperature dependence of the elastic constants for MgO, differential stress can be evaluated throughout deformation. Details of the methodology and analysis will be presented and sources of experimental uncertainties will be discussed.

  5. Effect of Laser Annealing of Common Solid Pressure Media on Pressure Gradients in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Uts, I.; Glazyrin, K.; Lee, K. K.

    2012-12-01

    Advances in experimental techniques allow for the studying of geophysics and planetary science related materials under high pressure and high temperature conditions. With the intrinsic limits of the multianvil apparatus, compression in a diamond anvil cell (DAC) has become the preferred method for creating the extreme conditions of planetary interiors. High pressures up to 1 Mbar can be routinely obtained in laboratories with the use of DACs. Additionally, as in situ laser heating is becoming progressively more affordable for DACs, it is becoming more common to find laser heating setups in many large scale facilities. After the sample material, the pressure medium is the second most important ingredient for a successful high pressure DAC experiment. Not every pressure medium is equally suitable for every experiment. For example, solid pressure media are more persistent than gaseous pressure media if high temperature heating is required. The melting point of the former is much higher, and melting of pressure media may induce undesirable sample shift in the pressure chamber. However, the most important characteristic of a pressure medium is its ability to maintain hydrostaticity in the DAC. The media, particularly solid pressure media, become less effective with increasing pressure. One of the most popular ways of alleviating pressure gradients is through laser annealing of the sample. We explore the effectiveness of this technique in relation to common pressure media, namely, alkali metal halides NaCl, CsCl, KCl, LiF, and oxide MgO. The samples were laser annealed at temperatures above 2000 K. Pressure gradients were determined through the analysis of diamond Raman and ruby fluorescence peaks before and after annealing the sample with a near-infrared laser. We find that the effect of annealing varies for different materials. For some (NaCl and KCl), it reduces pressure gradients considerably, but for the others (MgO), the effect of annealing is less profound.

  6. African Americans with Asthma

    PubMed Central

    Barnes, Kathleen C.; Grant, Audrey V.; Hansel, Nadia N.; Gao, Peisong; Dunston, Georgia M.

    2007-01-01

    It has been well established that genetic factors strongly affect susceptibility to asthma and its associated traits. It is less clear to what extent genetic variation contributes to the ethnic disparities observed for asthma morbidity and mortality. Individuals of African descent with asthma have more severe asthma, higher IgE levels, a higher degree of steroid dependency, and more severe clinical symptoms than individuals of European descent with asthma but relatively few studies have focused on this particularly vulnerable ethnic group. Similar underrepresentation exists for other minorities, including Hispanics. In this review, a summary of linkage and association studies in populations of African descent is presented, and the role of linkage disequilibrium in the dissection of a complex trait such as asthma is discussed. Consideration for the impact of population stratification in recently admixed populations (i.e., European, African) is essential in genetic association studies focusing on African ancestry groups. With the most recent update on the International HapMap Project, efficient selection of haplotype tagging single nucleotide polymorphisms (htSNPs) for African Americans has accelerated and efficiency of htSNPs chosen from one population to represent other continental groups (e.g., African) has been demonstrated. Cutting-edge approaches, such as genomewide association studies, admixture mapping, and phylogenetic analyses, offer new opportunities for dissecting the genetic basis for asthma in populations of African descent. PMID:17202293

  7. Characterizing the admixed African ancestry of African Americans

    PubMed Central

    2009-01-01

    Background Accurate, high-throughput genotyping allows the fine characterization of genetic ancestry. Here we applied recently developed statistical and computational techniques to the question of African ancestry in African Americans by using data on more than 450,000 single-nucleotide polymorphisms (SNPs) genotyped in 94 Africans of diverse geographic origins included in the HGDP, as well as 136 African Americans and 38 European Americans participating in the Atherosclerotic Disease Vascular Function and Genetic Epidemiology (ADVANCE) study. To focus on African ancestry, we reduced the data to include only those genotypes in each African American determined statistically to be African in origin. Results From cluster analysis, we found that all the African Americans are admixed in their African components of ancestry, with the majority contributions being from West and West-Central Africa, and only modest variation in these African-ancestry proportions among individuals. Furthermore, by principal components analysis, we found little evidence of genetic structure within the African component of ancestry in African Americans. Conclusions These results are consistent with historic mating patterns among African Americans that are largely uncorrelated to African ancestral origins, and they cast doubt on the general utility of mtDNA or Y-chromosome markers alone to delineate the full African ancestry of African Americans. Our results also indicate that the genetic architecture of African Americans is distinct from that of Africans, and that the greatest source of potential genetic stratification bias in case-control studies of African Americans derives from the proportion of European ancestry. PMID:20025784

  8. Sea level history in 3D: Data acquisition and processing for an ultra-high resolution MCS survey across IODP Expedition 313 drillsite

    NASA Astrophysics Data System (ADS)

    Nedimovic, M. R.; Mountain, G. S.; Austin, J. A., Jr.; Fulthorpe, C.; Aali, M.; Baldwin, K.; Bhatnagar, T.; Johnson, C.; Küçük, H. M.; Newton, A.; Stanley, J.

    2015-12-01

    In June-July 2015, we acquired the first 3D/2D hybrid (short/long streamer) multichannel seismic (MCS) reflection dataset. These data were collected simultaneously across IODP Exp. 313 drillsites, off New Jersey, using R/V Langsethand cover ~95% of the planned 12x50 km box. Despite the large survey area, the lateral and vertical resolution for the 3D dataset is almost a magnitude of order higher than for data gathered for standard petroleum exploration. Such high-resolution was made possible by collection of common midpoint (CMP) lines whose combined length is ~3 times the Earth's circumference (~120,000 profile km) and a source rich in high-frequencies. We present details on the data acquisition, ongoing data analysis, and preliminary results. The science driving this project is presented by Mountain et al. The 3D component of this innovative survey used an athwartship cross cable, extended laterally by 2 barovanes roughly 357.5 m apart and trailed by 24 50-m P-Cables spaced ~12.5 m with near-trace offset of 53 m. Each P-Cable had 8 single hydrophone groups spaced at 6.25 m for a total of 192 channels. Record length was 4 s and sample rate 0.5 ms, with no low cut and an 824 Hz high cut filter. We ran 77 sail lines spaced ~150 m. Receiver locations were determined using 2 GPS receivers mounted on floats and 2 compasses and depth sensors per streamer. Streamer depths varied from 2.1 to 3.7 m. The 2D component used a single 3 km streamer, with 240 9-hydrophone groups spaced at 12.5 m, towed astern with near-trace offset of 229 m. The record length was 4 s and sample rate 0.5 ms, with low cut filter at 2 Hz and high cut at 412 Hz. Receiver locations were recorded using GPS at the head float and tail buoy, combined with 12 bird compasses spaced ~300 m. Nominal streamer depth was 4.5 m. The source for both systems was a 700 in3 linear array of 4 Bolt air guns suspended at 4.5 m towing depth, 271.5 m behind the ship's stern. Shot spacing was 12.5 m. Data analysis to

  9. African American Health

    MedlinePlus

    ... early years. Health differences are often due to economic and social conditions that are more common among African Americans ... organizations, education, business, transportation, and housing, to create social and economic conditions that promote health starting in childhood. Link ...

  10. Experimental Investigation of Magnetic Superconducting, and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures Using Designer Diamond Anvils

    SciTech Connect

    Maple, M. Brian

    2005-09-13

    Pressure is a powerful control parameter, owing to its ability to affect crystal and electronic structure without introducing defects, for the investigation of condensed matter systems. Some f-electron, heavy-fermion materials display interesting and novel behavior when exposed to pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require extreme conditions such as ultrahigh pressures, high magnetic fields, and ultralow temperatures to sufficiently explore the important properties. To that end, we have been funded to develop an ultrahigh pressure facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena under extreme conditions. Our goals for the second year of this grant were as follows: (a) perform electrical resistivity measurements on novel samples at a myriad of pressures using conventional piston-cylinder techniques, Bridgman anvil techniques, and diamond anvil cell technology; (b) install, commission, and operate an Oxford Kelvinox MX-100 dilution refrigerator for access to ultralow temperatures and high magnetic fields. (c) continue the development of diamond anvil cell (DAC) technology. During the past year, we have successfully installed the Oxford Kelvinox MX-100 dilution refrigerator and verified its operability down to 12 mK. We have begun an experimental program to systematically investigate the f-electron compound URu2Si2 under pressure and in the presence of magnetic fields. We have also continued our collaborative work with Sam Weir at Lawrence Livermore National Laboratory (LLNL) on Au4V and implemented a new corollary study on Au1-xVx using ultrahigh pressures. We have continued developing our DAC facility by designing and constructing an apparatus for in situ pressure measurement as well as designing high pressure cells. This report serves to highlight the progress we have made

  11. Containment of fluid samples in the hydrothermal diamond-anvil cell without the use of metal gaskets: Performance and advantages for in situ analysis

    USGS Publications Warehouse

    Chou, I.-Ming; Bassett, William A.; Anderson, Alan J.; Mayanovic, Robert A.; Shang, L.

    2008-01-01

    Metal gaskets (Re, Ir, Inconel, or stainless steel) normally used to contain fluid samples in the hydrothermal diamond-anvil cell (HDAC) are sometimes undesirable due to possible contamination and to gasket deformation at high pressures and temperatures resulting in nonisochoric behavior. Furthermore, in x-ray spectroscopic experiments, metal gaskets may attenuate the incident x-ray beam and emitted fluorescence x-rays, and the interaction of scattered radiation with the gasket may produce fluorescence that interferes with the x-ray spectrum of the sample. New arrangements and procedures were tested for the operation of the HDAC without using the metal gaskets. Distilled, de-ionized water was loaded into the sample chamber, a laser-milled recess 300 ??m in diameter and ???50 ??m deep centered in the 1.0 mm face of the lower diamond anvil, and sealed by pressing the top diamond anvil face directly against the lower one without a metal gasket in between. A maximum sample pressure of 202 MPa at 617 ??C was maintained for a duration of 10 min without evidence of leakage. A small change in fluid density was observed in one experiment where the sample was held at 266 MPa at 708 ??C for 10 min. The gasketless HDAC was also employed in x-ray absorption spectroscopy experiments, where, in addition to the sample chamber in the lower diamond, two grooves were milled at a 90?? angle to each other around the sample chamber to minimize the attenuation of incident and fluorescent x rays. With a minimum distance between the sample chamber and the grooves of 80 ??m, a pressure of 76 MPa at 500 ??C was maintained for 2 h with no change in the original fluid density. ?? 2008 American Institute of Physics.

  12. Containment of fluid samples in the hydrothermal diamond-anvil cell without the use of metal gaskets: performance and advantages for in situ analysis.

    PubMed

    Chou, I-Ming; Bassett, William A; Anderson, Alan J; Mayanovic, Robert A; Shang, Linbo

    2008-11-01

    Metal gaskets (Re, Ir, Inconel, or stainless steel) normally used to contain fluid samples in the hydrothermal diamond-anvil cell (HDAC) are sometimes undesirable due to possible contamination and to gasket deformation at high pressures and temperatures resulting in nonisochoric behavior. Furthermore, in x-ray spectroscopic experiments, metal gaskets may attenuate the incident x-ray beam and emitted fluorescence x-rays, and the interaction of scattered radiation with the gasket may produce fluorescence that interferes with the x-ray spectrum of the sample. New arrangements and procedures were tested for the operation of the HDAC without using the metal gaskets. Distilled, de-ionized water was loaded into the sample chamber, a laser-milled recess 300 microm in diameter and approximately 50 microm deep centered in the 1.0 mm face of the lower diamond anvil, and sealed by pressing the top diamond anvil face directly against the lower one without a metal gasket in between. A maximum sample pressure of 202 MPa at 617 degrees C was maintained for a duration of 10 min without evidence of leakage. A small change in fluid density was observed in one experiment where the sample was held at 266 MPa at 708 degrees C for 10 min. The gasketless HDAC was also employed in x-ray absorption spectroscopy experiments, where, in addition to the sample chamber in the lower diamond, two grooves were milled at a 90 degrees angle to each other around the sample chamber to minimize the attenuation of incident and fluorescent x rays. With a minimum distance between the sample chamber and the grooves of 80 microm, a pressure of 76 MPa at 500 degrees C was maintained for 2 h with no change in the original fluid density.

  13. Preparation of W-Ta thin-film thermocouple on diamond anvil cell for in-situ temperature measurement under high pressure

    SciTech Connect

    Yang Jie; Li Ming; Zhang Honglin; Gao Chunxiao

    2011-04-15

    In this paper, a W-Ta thin-film thermocouple has been integrated on a diamond anvil cell by thin-film deposition and photolithography methods. The thermocouple was calibrated and its thermal electromotive force was studied under high pressure. The results indicate that the thermal electromotive force of the thermocouple exhibits a linear relationship with temperature and is not associated with pressure. The resistivity measurement of ZnS powders under high pressure at different temperatures shows that the phase transition pressure decreases as the temperature increases.

  14. Preparation of W-Ta thin-film thermocouple on diamond anvil cell for in-situ temperature measurement under high pressure.

    PubMed

    Yang, Jie; Li, Ming; Zhang, Honglin; Gao, Chunxiao

    2011-04-01

    In this paper, a W-Ta thin-film thermocouple has been integrated on a diamond anvil cell by thin-film deposition and photolithography methods. The thermocouple was calibrated and its thermal electromotive force was studied under high pressure. The results indicate that the thermal electromotive force of the thermocouple exhibits a linear relationship with temperature and is not associated with pressure. The resistivity measurement of ZnS powders under high pressure at different temperatures shows that the phase transition pressure decreases as the temperature increases.

  15. Experimental method for in situ determination of material textures at simultaneous high pressure and high temperature by means of radial diffraction in the diamond anvil cell.

    PubMed

    Liermann, Hanns-Peter; Merkel, Sébastien; Miyagi, Lowell; Wenk, Hans-Rudolf; Shen, Guoyin; Cynn, Hyunchae; Evans, William J

    2009-10-01

    We introduce the design and capabilities of a resistive heated diamond anvil cell that can be used for side diffraction at simultaneous high pressure and high temperature. The device can be used to study lattice-preferred orientations in polycrystalline samples up to temperatures of 1100 K and pressures of 36 GPa. Capabilities of the instrument are demonstrated with preliminary results on the development of textures in the bcc, fcc, and hcp polymorphs of iron during a nonhydrostatic compression experiment at simultaneous high pressure and high temperature.

  16. New Experimental Method for In Situ Determination of Material Textures at Simultaneous High-Pressure and -Temperature by Means of Radial Diffraction in the Diamond Anvil Cell.

    SciTech Connect

    Liermann, H; Merkel, S; Miyagi, L; Wenk, H; Shen, G; Cynn, H; Evans, W J

    2009-07-15

    We introduce the design and capabilities of a new resistive heated diamond anvil cell that can be used for side diffraction at simultaneous high-pressure and -temperature. The device can be used to study lattice-preferred orientations in polycrystalline samples up to temperatures of 1100 K and pressures of 36 GPa. Capabilities of the instrument are demonstrated with preliminary results on the development of textures in the BCC, FCC and HCP polymorphs of iron during a non-hydrostatic compression experiment at simultaneous high-pressure and -temperature.

  17. Synthesis of Binary Transition Metal Nitrides, Carbides and Borides from the Elements in the Laser-Heated Diamond Anvil Cell and Their Structure-Property Relations

    PubMed Central

    Friedrich, Alexandra; Winkler, Björn; Juarez-Arellano, Erick A.; Bayarjargal, Lkhamsuren

    2011-01-01

    Transition metal nitrides, carbides and borides have a high potential for industrial applications as they not only have a high melting point but are generally harder and less compressible than the pure metals. Here we summarize recent advances in the synthesis of binary transition metal nitrides, carbides and borides focusing on the reaction of the elements at extreme conditions generated within the laser-heated diamond anvil cell. The current knowledge of their structures and high-pressure properties like high-(p,T) stability, compressibility and hardness is described as obtained from experiments. PMID:28824101

  18. Preparation of W-Ta thin-film thermocouple on diamond anvil cell for in-situ temperature measurement under high pressure

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Li, Ming; Zhang, Honglin; Gao, Chunxiao

    2011-04-01

    In this paper, a W-Ta thin-film thermocouple has been integrated on a diamond anvil cell by thin-film deposition and photolithography methods. The thermocouple was calibrated and its thermal electromotive force was studied under high pressure. The results indicate that the thermal electromotive force of the thermocouple exhibits a linear relationship with temperature and is not associated with pressure. The resistivity measurement of ZnS powders under high pressure at different temperatures shows that the phase transition pressure decreases as the temperature increases.

  19. Experimental issues in in-situ synchrotron x-ray diffraction at high pressure and temperature by using a laser-heated diamond-anvil cell

    SciTech Connect

    Yoo, C.S.

    1997-12-01

    An integrated technique of diamond-anvil cell, laser-heating and synchrotron x-ray diffraction technologies is capable of structural investigation of condensed matter in an extended region of high pressures and temperatures above 100 GPa and 3000 K. The feasibility of this technique to obtain reliable data, however, strongly depends on several experimental issues, including optical and x-ray setups, thermal gradients, pressure homogeneity, preferred orientation, and chemical reaction. In this paper, we discuss about these experimental issues together with future perspectives of this technique for obtaining accurate data.

  20. Energy dispersive X-ray diffraction in the diamond anvil, high-pressure apparatus - Comparison of synchrotron and conventional X-ray sources

    NASA Technical Reports Server (NTRS)

    Spain, I. L.; Black, D. R.

    1985-01-01

    The use of both conventional fixed-anode X-ray sources and synchrotron radiation to carry out energy-dispersive X-ray diffraction experiments at high pressure in a diamond anvil cell, is discussed. The photon flux at the sample and at the detector for the two cases are compared and the results are presented in graphs. It is shown that synchrotron radiation experiments can be performed with nearly two orders of magnitude increase in data rate if superior detectors and detector electronics are available.

  1. Study of the reaction products of SF6 and C in the laser heated diamond anvil cell by pair distribution function analysis and micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rademacher, N.; Bayarjargal, L.; Morgenroth, W.; Bauer, J. D.; Milman, V.; Winkler, B.

    2015-05-01

    The decomposition of SF6 in the presence of glassy carbon was induced in laser heated diamond anvil cells at 10-11 GPa and 2000-2500 K. The reaction products were characterised by synchrotron X-ray diffraction, including high pressure pair distribution function analysis, and micro-Raman spectroscopy combined with atomistic model calculations. The decomposition leads to elemental amorphous helical sulfur and crystalline CF4-III. Two different sulfur phases, namely helical Sμ and crystalline α-S8, were observed after recovering the laser heated samples of different experiments at ambient conditions.

  2. Energy dispersive X-ray diffraction in the diamond anvil, high-pressure apparatus - Comparison of synchrotron and conventional X-ray sources

    NASA Technical Reports Server (NTRS)

    Spain, I. L.; Black, D. R.

    1985-01-01

    The use of both conventional fixed-anode X-ray sources and synchrotron radiation to carry out energy-dispersive X-ray diffraction experiments at high pressure in a diamond anvil cell, is discussed. The photon flux at the sample and at the detector for the two cases are compared and the results are presented in graphs. It is shown that synchrotron radiation experiments can be performed with nearly two orders of magnitude increase in data rate if superior detectors and detector electronics are available.

  3. A Method for Selecting Software for Dynamic Event Analysis II: the Taylor Anvil and Dynamic Brazilian Tests

    SciTech Connect

    W. D. Richins; J. M. Lacy; T. K. Larson; S. R. Novascone

    2008-05-01

    fracture at the center of the specimen that propagates toward the loading points until the cylinder is split. To generate a dynamic load, different methods such as a drop-weight or a split Hopkinson pressure bar are employed. The Taylor anvil and dynamic Brazilian test analyses are presented, including discussion of the analysis approach for each of the five subject software packages; comparison of results both among the codes and to physical test results; and conclusions as to the applicability of the subject codes to these two problems. Studies of the remaining three benchmark problems and overall conclusions will be presented in future reports.

  4. The Metal-Silicate Partitioning of Tungsten at Magma Ocean Conditions Using a Laser-Heated Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Bennett, N.; Jackson, C.; Fei, Y.; Bullock, E. S.; Armstrong, J. T.

    2015-12-01

    The primitive upper mantle (PUM) represents the silicate residue of terrestrial core formation and should reflect element partitioning between metal and silicate melts that equilibrated in a magma ocean. Laboratory experiments suggest that the W/Mo ratio of PUM is only reproduced if S is added to the Earth during the late stages of accretion (Wade et al. 2012). Core-segregation, however, is posited to occur at >35 GPa and >3000 K; above the pressure range explored by existing W partitioning experiments and conditions under which O may also enter core-forming metal. The effect of light element solutes on a metallic Fe liquid can be modeled using experimentally determined interaction parameters (ɛ). On the basis of ɛ values determined at ambient pressure, both O and S should interact strongly with W (ɛw-o = 4.1, ɛw-s = 6.1), possibly complicating the history of W distribution during accretion. We have performed experiments to assess the metal-silicate partitioning of W at conditions directly relevant to those expected for the base of a magma ocean, under which O enters the metal phase. Experiments were performed at 15-50 GPa in a diamond anvil cell, using Re gaskets and an MgO pressure medium. In several instances, cells were loaded with two sample mixtures, containing W in either oxidized or reduced form. Heating spots subject to the same temperature and heating duration but different initial W oxidation state will be used to assess if heating times were sufficient to approach equilibrium. Samples were laser-heated at sector 13 of the Advanced Photon Source then recovered for analysis using a focused ion beam, to reveal cross-sections through the heated spot. Samples comprise a Fe-rich metal bleb, surrounded by silicate glass. The quenched metal contains exsolved spherules of a Si+O-rich phase, indicating significant solution of these elements at high pressure and temperature. Work is ongoing to quantify the element distribution between metal and silicate phases.

  5. Noble Gases Analyses of Samples Synthesized at High P and T in a Multi Anvil Press Device: Protocol and Implications

    NASA Astrophysics Data System (ADS)

    Bonnefoy, B.; Andrault, D.; Moreira, M.; Bolfan-Casanova, N.

    2007-12-01

    Noble gases (He-Ne-Ar-Kr-Xe) in mantle-derived samples allow an undisputable tracing of different sources of materials. Concerning the deep mantle part, the study of noble gases suggests that a "primordial" component (which is non or partially degassed) exists. Nevertheless, this conclusion is challenged by several observations, both geophysical and geochemical, suggesting that contrariwise the mantle is now totally depleted, degassed or renewed by convection. Furthermore, the lack of experimental data disables quantitative modelling of geochemistry processes. It is still unknown how much the fractionations are dependent on the conditions on pressure, temperature and chemical composition in the mantle. Recent studies [1-3] suggest a more incompatible behavior for noble gases in comparison to their parent element (K for Ar, U + Th for He) in very specific conditions of pressure, temperature, and chemical composition. Nevertheless, those studies focus on only particular compositions or pressures or only one single noble gas. No exhaustive studies (of all nobles gases at different pressures, temperatures and compositions) were accomplished on this subject so far. We set up a new experimental protocol allowing the analyses of rare gases in samples synthesized under mantle conditions, at high pressures and temperatures. This new protocol associates the use of a gas loading device [4], a multi-anvil press device (INSU MAP, Clermont-Ferrand, France), a laser ablation coupled to mass- spectrometer for the noble gases analysis (excimer laser, λ = 193 nm), and a 3D profilometry device to quantify the amount of ablated material. We will present an application of these methods on the noble gases partitioning between solid and liquid natural phases in the 3-5 GPa pressure range and for temperature of 1400 to 1600°C. [1] E.M. Chamorro, R.A Brooker, J.-A Wartho, B.J. Wodd, S.P. Kelley and J.D. Blundy. Ar and K partitioning between clinopyroxene and silicate melt to 8 GPa

  6. Phase relations of an Fe-Ni alloy determined in an internally-heated diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Komabayashi, T.; Hirose, K.; Ohishi, Y.

    2011-12-01

    The Earth's core is believed to contain several amounts of nickel while its major component is iron. In order to understand the nature of the Earth's core, we conducted in-situ X-ray diffraction study of an iron-nickel alloy (Fe0.9Ni0.1) in an internally-resistive heated diamond anvil cell (DAC) up to pressures (P) and temperatures (T) of 110 GPa and 2500 K. High-P-T experiments with the angle-dispersive X-ray diffraction system were conducted at the SPring-8. The improved internally-heated DAC configuration provides stable heating with reliable temperature and pressure determination and phase identification [1]. Due to this configuration, we are able to put tight constraints on the P-T location and the width of the two phase loop of the γ (face-centered cubic structure) and ɛ (hexagonal close-packed structure) phase transition boundary. We also constructed a thermal equation of state (EoS) for the ɛ phase of Fe0.9Ni0.1, which served as the pressure scale for the present experiment. We evaluated the 300-K compression curve for the ɛ phase to P =100 GPa based on P-scales of Au and the diamond Raman. Thermal pressure part of the EoS was assumed to be the same as for pure iron [2]. Results show that γ and ɛ transition boundary in Fe0.9Ni0.1 is located at lower temperatures than that of pure iron, consistent with the previous works which used the laser-heated DAC [3,4]. However, the width of the two phase loop is narrower than those of previous works. We will present the P-T phase diagram and the density of ɛ phase in Fe0.9Ni0.1, and discuss possible roles of the addition of nickel to iron in the Earth's core. References [1] Komabayashi et al. (2009) EPSL 282, 252-257. [2] Dewaele et al. (2006) PRL 97, 215504. [3] Lin et al. (2002) GRL 29, 10.1029/2002GL015089. [4] Mao et al. (2006) PEPI 155, 146-151.

  7. Geoconservation - a southern African and African perspective

    NASA Astrophysics Data System (ADS)

    Reimold, Wolf Uwe

    1999-10-01

    In contrast to Europe, where geoconservation is actively pursued in most countries and where two international symposia on this subject have been staged in 1991 and 1996, geoconservation in Africa has indeed a very poor record. Considering the wealth of outstanding geological sites and the importance African stratigraphy has within the global geological record, pro-active geoconservation on this continent has not featured very prominently to date. In the interest of science, education and tourism, unique and typical geosites need to be identified, catalogued, and prioritised with the aim being their protection. Most African countries do not have vibrant non-governmental organisations such as a strong geological society, which could drive projects like geoconservation, or strong support from the private sector for environmental work. Here, a case is made for the role that established National Geological Surveys, some of which are already involved with retroactive environmental geological work, could play in the forefront of pro-active geoconservation and site protection.

  8. Gout in African Americans.

    PubMed

    Krishnan, Eswar

    2014-09-01

    African Americans have a substantially higher prevalence of risk factors for gout than Caucasians. The aim of the present study was to compare the risk for incident gout among African Americans and Caucasians. Incidence rates of physician-diagnosed gout among 11,559 Caucasian men and 931 African American men aged 35 to 57 years and at high cardiovascular risk, observed for 7 years as a part of the Multiple Risk Factor Intervention Trial, were analyzed. Cox regression models were used to account for potential confounding by age, body mass index, diuretic use, hypertension and diabetes status, aspirin and alcohol consumption, and kidney disease. At baseline, after accounting for risk factors, African Americans had a 14% lower prevalence of hyperuricemia than Caucasians. Incidence of gout increased with increasing prevalence of risk factors in both Caucasians and African Americans. Ethnic disparities in incidence rates were most apparent among those without other risk factors for gout. In separate Cox regression models, after accounting for risk factors, African American ethnicity was associated with a hazard ratio of 0.78 (95% confidence interval [CI], 0.66-0.93) for physician-diagnosed gout and 0.88 (95% CI, 0.85-0.90) for incident hyperuricemia. Significant interactions were observed; the association was the strongest (hazard ratio 0.47; 0.37-0.60). These associations were unaffected by addition of serum urate as a covariate or by using alternate case definitions for gout. After accounting for the higher prevalence of risk factors, African American ethnicity is associated with a significantly lower risk for gout and hyperuricemia compared with Caucasian ethnicity. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Narcolepsy in African Americans.

    PubMed

    Kawai, Makoto; O'Hara, Ruth; Einen, Mali; Lin, Ling; Mignot, Emmanuel

    2015-11-01

    Although narcolepsy affects 0.02-0.05% of individuals in various ethnic groups, clinical presentation in different ethnicities has never been fully characterized. Our goal was to study phenotypic expression across ethnicities in the United States. Cases of narcolepsy from 1992 to 2013 were identified from searches of the Stanford Center for Narcolepsy Research database. International Classification of Sleep Disorders, Third Edition diagnosis criteria for type 1 and type 2 narcolepsy were used for inclusion, but subjects were separated as with and without cataplexy for the purpose of data presentation. Information extracted included demographics, ethnicity and clinical data, HLA-DQB1*06:02, polysomnography (PSG), multiple sleep latency test (MSLT) data, and cerebrospinal fluid (CSF) hypocretin-1 level. 182 African-Americans, 839 Caucasians, 35 Asians, and 41 Latinos with narcolepsy. Sex ratio, PSG, and MSLT findings did not differ across ethnicities. Epworth Sleepiness Scale (ESS) score was higher and age of onset of sleepiness earlier in African Americans compared with other ethnicities. HLA-DQB1*06:02 positivity was higher in African Americans (91.0%) versus others (76.6% in Caucasians, 80.0% in Asians, and 65.0% in Latinos). CSF hypocretin-1 level, obtained in 222 patients, was more frequently low (≤ 110 pg/ml) in African Americans (93.9%) versus Caucasians (61.5%), Asians (85.7%) and Latinos (75.0%). In subjects with low CSF hypocretin-1, African Americans (28.3%) were 4.5 fold more likely to be without cataplexy when compared with Caucasians (8.1%). Narcolepsy in African Americans is characterized by earlier symptom onset, higher Epworth Sleepiness Scale score, higher HLA-DQB1*06:02 positivity, and low cerebrospinal fluid hypocretin-1 level in the absence of cataplexy. In African Americans, more subjects without cataplexy have type 1 narcolepsy. © 2015 Associated Professional Sleep Societies, LLC.

  10. Use of a multichannel collimator for structural investigation of low-Z dense liquids in a diamond anvil cell: Validation on fluid H{sub 2} up to 5 GPa

    SciTech Connect

    Weck, Gunnar; Spaulding, Dylan; Loubeyre, Paul; Garbarino, Gaston; Mezouar, Mohamed; Ninet, Sandra; Datchi, Frederic

    2013-06-15

    We report the first application of a multichannel collimator (MCC) to perform quantitative structure factor measurements of dense low-Z fluids in a diamond anvil cell (DAC) using synchrotron x-ray diffraction. The MCC design, initially developed for the Paris-Edinburgh large volume press geometry, has been modified for use with diamond anvil cells. A good selectivity of the diffracted signal of the dense fluid sample is obtained due to a large rejection of the Compton diffusion from the diamond anvils. The signal to background ratio is significantly improved. We modify previously developed analytical techniques for quantitative measurement of the structure factor of fluids in DACs [J. H. Eggert, G. Weck, P. Loubeyre, and M. Mezouar, Phys. Rev. B 65, 174105 (2002)] to account for the contribution of the MCC. We present experimental results on liquids argon and hydrogen at 296 K to validate our method and test its limits, respectively.

  11. Hydrothermal studies in a new diamond anvil cell up to 10 GPa and from -190°C to 1200°C

    USGS Publications Warehouse

    Bassett, William A.; Shen, A.H.; Bucknum, M.; Chou, I.-Ming

    1993-01-01

    The new hydrothermal diamond anvil cell (HDAC) has been designed for optical microscopy and X-ray diffraction at pressures up to 10 GPa and temperatures between −190°C and 1200°C. Laser light reffected from the top and bottom anvil faces and the top and bottom solid sample faces produce interference fringes that provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in solid samples due to transitions and reactions. Synchrotron radiation has been used to make X-ray diffraction patterns of samples under hydrothermal conditions. Individual heaters and individual thermocouples provide temperature control with an accuracy of ±0.5°C. Liquid nitrogen directly introduced into the HDAC has been used to reduce the sample temperature to −190°C. The α-β phase boundary of quartz has been used to calculate the transition pressures from measured transition temperatures. With this method we have redetermined 5 isochores of H2O up to 850°C and 1.2 GPa at which the solution rate of the quartz became so rapid that the quartz dissolved completely before the α-β transition could be observed. When silica solutions were cooled, opal spherules and rods formed.

  12. CO signatures in subtropical convective clouds and anvils during CRYSTAL-FACE: An analysis of convective transport and entrainment using observations and a cloud-resolving model

    NASA Astrophysics Data System (ADS)

    Lopez, Jimena P.; Fridlind, Ann M.; Jost, Hans-Jürg; Loewenstein, Max; Ackerman, Andrew S.; Campos, Teresa L.; Weinstock, Elliot M.; Sayres, David S.; Smith, Jessica B.; Pittman, Jasna V.; Hallar, A. Gannet; Avallone, Linnea M.; Davis, Sean M.; Herman, Robert L.

    2006-05-01

    Convective systems are an important mechanism in the transport of boundary layer air into the upper troposphere. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, in July 2002, was developed as a comprehensive atmospheric mission to improve knowledge of subtropical cirrus systems and their roles in regional and global climate. In situ measurements of carbon monoxide (CO), water vapor (H2Ov), and total water (H2Ot) aboard NASA's WB-57F aircraft and CO aboard the U.S. Navy's Twin Otter aircraft were obtained to study the role of convective transport. Three flights sampled convective outflow on 11, 16 and 29 July found varying degrees of CO enhancement relative to the free troposphere. A cloud-resolving model used the in situ observations and meteorological fields to study these three systems. Several methods of filtering the observations were devised here using ice water content, relative humidity with respect to ice, and particle number concentration as a means to statistically sample the model results to represent the flight tracks. A weighted histogram based on ice water content observations was then used to sample the simulations for the three flights. In addition, because the observations occurred in the convective outflow cirrus and not in the storm cores, the model was used to estimate the maximum CO within the convective systems. In general, anvil-level air parcels contained an estimated 20-40% boundary layer air in the analyzed storms.

  13. LETTER TO THE EDITOR: Homoepitaxial diamond films on diamond anvils with metallic probes: the diamond/metal interface up to 74 GPa

    NASA Astrophysics Data System (ADS)

    Catledge, Shane A.; Vohra, Yogesh K.; Weir, Samuel T.; Akella, Jagan

    1997-02-01

    A (100)-oriented natural type-Ia brilliant-cut diamond anvil with thin zirconium electrical probes sputtered onto the culet was coated with an insulating film of diamond using microwave-plasma-enhanced chemical vapour deposition (MPCVD). The critical issue in this high-pressure study is the quality of the homoepitaxial diamond film and its correlation with the mechanical strength of the diamond film/metallic probe interface. We report the first high-pressure study on a homoepitaxial diamond film and underlying zirconium probes to a pressure of 74 GPa. The metallic probes were observed through a transparent lithium fluoride sample with ruby serving as a pressure sensor. After decompression, Raman spectroscopy revealed that the homoepitaxial film was free from deformation and delamination despite the presence of some 0953-8984/9/7/001/img7-bonded carbon at the Zr/diamond interface and within the bulk of the film itself. The present study demonstrates that the presence of residual defects and graphitic impurities has no significant effect on high-pressure applications of homoepitaxial diamond films. This opens up new areas of research with diamond anvil cell devices including those of ohmic heating and electrical transport measurements at ultra-high pressures.

  14. Bridging the gap between static and dynamic compression: an inertial confinement approach to laser heating experiments in the diamond-anvil cell

    NASA Astrophysics Data System (ADS)

    McWilliams, R. S.; Goncharov, A. F.; Mahmood, M. F.; Dalton, D. A.

    2012-12-01

    Low-molecular weight materials - including those abundant in giant planets such as H2 - are difficult to study experimentally at the extreme pressures and temperatures of planetary interiors. The most extreme conditions have been traditionally accessible only with dynamic compression (e.g. shock) techniques that confine extreme states via short timescales. In static compression (e.g. laser-heated diamond-anvil cell) methods, difficulties related to flow, reaction, diffusion, and anvil failure on the typically-longer experimental duration can limit accessible temperatures to below those encountered in planets. By accelerating laser-heating experiments in the diamond cell using single-pulse laser heating combined with fast optical diagnostics, we have extended accessible temperatures in light elements (e.g. H2, N2) to temperatures several times those previously achieved in the diamond cell and to planetary-interior conditions previously achieved only in shock compression. The onset of electronic transformations at extreme temperatures are characterized, with optical absorption spectra showing dramatic deviations from a simple (Drüde) metal, and the onset of dielectric-conductor transformation at lower temperature and pressure than expected based on theoretical phase boundaries.

  15. A design of backing seat and gasket assembly in diamond anvil cell for accurate single crystal x-ray diffraction to 5 GPa.

    PubMed

    Komatsu, K; Kagi, H; Yasuzuka, T; Koizumi, T; Iizuka, R; Sugiyama, K; Yokoyama, Y

    2011-10-01

    We designed a new cell assembly of diamond anvil cells for single crystal x-ray diffraction under pressure and demonstrate the application of the cell to the crystallographic studies for ice VI and ethanol high-pressure (HP) phase at 0.95(5) GPa and 1.95(2) GPa, respectively. The features of the assembly are: (1) the platy anvil and unique-shaped backing seat (called as "Wing seat") allowing the extremely wide opening angle up to ±65°, (2) the PFA-bulk metallic glass composite gasket allowing the easy attenuation correction and less background. Thanks to the designed assembly, the R(int) values after attenuation corrections are fairly good (0.0125 and 0.0460 for ice VI and ethanol HP phase, respectively), and the errors of the refined parameters are satisfactory small even for hydrogen positions, those are comparable to the results which obtained at ambient conditions. The result for ice VI is in excellent agreement with the previous study, and that for ethanol HP phase has remarkable contributions to the revision to its structure; the H12 site, which makes gauche molecules with O1, C2, and C3 sites, may not exist so that only trans conformers are present at least at 1.95(2) GPa. The accurate intensities using the cell assembly allow us to extract the electron density for ethanol HP phase by the maximum entropy method.

  16. Space Efficient Opposed-Anvil High-Pressure Cell and Its Application to Optical and NMR Measurements up to 9 GPa

    NASA Astrophysics Data System (ADS)

    Kitagawa, Kentaro; Gotou, Hirotada; Yagi, Takehiko; Yamada, Atsushi; Matsumoto, Takehiko; Uwatoko, Yoshiya; Takigawa, Masashi

    2010-02-01

    We have developed a new type of opposed-anvil high pressure cell with substantially improved space efficiency. The clamp cell and the gasket are made of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used for the anvils. The assembled cell with the dimension φ 29 mm × 41 mm is capable of generating pressure up to 9 GPa over a relatively large volume of 7 mm3. Our cell is particularly suitable for those experiments which require large sample space to achieve good signal-to-noise ratio, such as the nuclear magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting medium to obtain good hydrostaticity. The pressure was calibrated in situ by measuring the fluorescence from ruby through a transparent moissanite (6H-SiC) window. We have measured the pressure and temperature dependences of the 63Cu nuclear-quadrupole-resonance (NQR) frequency of Cu2O, the in-plane Knight shift of metallic tin, and the Knight shift of platinum. These quantities can be used as reliable manometers to determine the pressure values in situ during the NMR/NQR experiments up to 9 GPa.

  17. CO Signatures in Subtropical Convective Clouds and Anvils during CRYSTAL-FACE: An Analysis of Convective Transport and Entrainment using Observations and a Cloud-Resolving Model

    NASA Technical Reports Server (NTRS)

    Lopez, Jimena P.; Fridlind, Ann M.; Jost, Hans-Juerg; Loewenstein, Max; Ackerman, Andrew S.; Campos, Teresa L.; Weinstock, Elliot M.; Sayres, David S.; Smith, Jessica B.; Pittman, Jasna V.

    2006-01-01

    Convective systems are an important mechanism in the transport of boundary layer air into the upper troposphere. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, in July 2002, was developed as a comprehensive atmospheric mission to improve knowledge of subtropical cirrus systems and their roles in regional and global climate. In situ measurements of carbon monoxide (CO), water vapor (H2Ov), and total water (H2Ot) aboard NASA's WB-57F aircraft and CO aboard the U.S. Navy's Twin Otter aircraft were obtained to study the role of convective transport. Three flights sampled convective outflow on 11, 16 and 29 July found varying degrees of CO enhancement relative to the free troposphere. A cloud-resolving model used the in situ observations and meteorological fields to study these three systems. Several methods of filtering the observations were devised here using ice water content, relative humidity with respect to ice, and particle number concentration as a means to statistically sample the model results to represent the flight tracks. A weighted histogram based on ice water content observations was then used to sample the simulations for the three flights. In addition, because the observations occurred in the convective outflow cirrus and not in the storm cores, the model was used to estimate the maximum CO within the convective systems. In general, anvil-level air parcels contained an estimated 20-40% boundary layer air in the analyzed storms.

  18. CO Signatures in Subtropical Convective Clouds and Anvils During CRYSTAL-FACE: An Analysis of Convective Transport and Entertainment Using Observations and a Cloud-Resolving Model

    NASA Technical Reports Server (NTRS)

    Lopez, Jimena P.; Fridlind, Ann M.; Jost, Hans-Jurg; Loewenstein, Max; Ackerman, Andrew S.; Campos, Teresa L.; Weinstock, Elliot M.; Sayres, David S.; Smith, Jessica B.; Pittman, Jasna V.; hide

    2006-01-01

    Convective systems are an important mechanism in the transport of boundary layer air into the upper troposphere. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign, in July 2002, was developed as a comprehensive atmospheric mission to improve knowledge of subtropical cirrus systems and their roles in regional and global climate. In situ measurements of carbon monoxide (CO), water vapor (H20v), and total water (H20t) aboard NASA's . WB-57F aircraft and CO aboard the U.S. Navy's Twin Otter aircraft were obtained to study the role of convective transport. Three flights sampled convective outflow on 11, 16 and 29 July found varying degrees of CO enhancement relative to the fiee troposphere. A cloud-resolving model used the in situ observations and meteorological fields to study these three systems. Several methods of filtering the observations were devised here using ice water content, relative humidity with respect to ice, and particle number concentration as a means to statistically sample the model results to represent the flight tracks. A weighted histogram based on ice water content observations was then used to sample the simulations for the three flights. In addition, because the observations occurred in the convective outflow cirrus and not in the storm cores, the model was used to estimate the maximum CO within the convective systems. In general, anvil-level air parcels contained an estimated 20-40% boundary layer air in the analyzed storms.

  19. Coccidioidomycosis in African Americans

    PubMed Central

    Ruddy, Barbara E.; Mayer, Anita P.; Ko, Marcia G.; Labonte, Helene R.; Borovansky, Jill A.; Boroff, Erika S.; Blair, Janis E.

    2011-01-01

    Coccidioidomycosis is caused by Coccidioides species, a fungus endemic to the desert regions of the southwestern United States, and is of particular concern for African Americans. We performed a PubMed search of the English-language medical literature on coccidioidomycosis in African Americans and summarized the pertinent literature. Search terms were coccidioidomycosis, Coccidioides, race, ethnicity, African, black, and Negro. The proceedings of the national and international coccidioidomycosis symposia were searched. All relevant articles and their cited references were reviewed; those with epidemiological, immunologic, clinical, and therapeutic data pertaining to coccidioidomycosis in African Americans were included in the review. Numerous studies documented an increased predilection for severe coccidioidal infections, coccidioidomycosis-related hospitalizations, and extrapulmonary dissemination in persons of African descent; however, most of the published studies are variably problematic. The immunologic mechanism for this predilection is unclear. The clinical features and treatment recommendations are summarized. Medical practitioners need to be alert to the possibility of coccidioidomycosis in persons with recent travel to or residence in an area where the disease is endemic. PMID:21193657

  20. Coccidioidomycosis in African Americans.

    PubMed

    Ruddy, Barbara E; Mayer, Anita P; Ko, Marcia G; Labonte, Helene R; Borovansky, Jill A; Boroff, Erika S; Blair, Janis E

    2011-01-01

    Coccidioidomycosis is caused by Coccidioides species, a fungus endemic to the desert regions of the southwestern United States, and is of particular concern for African Americans. We performed a PubMed search of the English-language medical literature on coccidioidomycosis in African Americans and summarized the pertinent literature. Search terms were coccidioidomycosis, Coccidioides, race, ethnicity, African, black, and Negro. The proceedings of the national and international coccidioidomycosis symposia were searched. All relevant articles and their cited references were reviewed; those with epidemiological, immunologic, clinical, and therapeutic data pertaining to coccidioidomycosis in African Americans were included in the review. Numerous studies documented an increased predilection for severe coccidioidal infections, coccidioidomycosis-related hospitalizations, and extrapulmonary dissemination in persons of African descent; however, most of the published studies are variably problematic. The immunologic mechanism for this predilection is unclear. The clinical features and treatment recommendations are summarized. Medical practitioners need to be alert to the possibility of coccidioidomycosis in persons with recent travel to or residence in an area where the disease is endemic.