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Sample records for in-situ high temperature

  1. Novel High Temperature Materials for In-Situ Sensing Devices

    SciTech Connect

    Florian Solzbacher; Anil Virkar; Loren Rieth; Srinivasan Kannan; Xiaoxin Chen; Hannwelm Steinebach

    2009-12-31

    The overriding goal of this project was to develop gas sensor materials and systems compatible with operation at temperatures from 500 to 700 C. Gas sensors operating at these temperatures would be compatible with placement in fossil-energy exhaust streams close to the combustion chamber, and therefore have advantages for process regulation, and feedback for emissions controls. The three thrusts of our work included investigating thin film gas sensor materials based on metal oxide materials and electroceramic materials, and also development of microhotplate devices to support the gas sensing films. The metal oxide materials NiO, In{sub 2}O{sub 3}, and Ga{sub 2}O{sub 3} were investigated for their sensitivity to H{sub 2}, NO{sub x}, and CO{sub 2}, respectively, at high temperatures (T > 500 C), where the sensing properties of these materials have received little attention. New ground was broken in achieving excellent gas sensor responses (>10) for temperatures up to 600 C for NiO and In{sub 2}O{sub 3} materials. The gas sensitivity of these materials was decreasing as temperatures increased above 500 C, which indicates that achieving strong sensitivities with these materials at very high temperatures (T {ge} 650 C) will be a further challenge. The sensitivity, selectivity, stability, and reliability of these materials were investigated across a wide range of deposition conditions, temperatures, film thickness, as using surface active promoter materials. We also proposed to study the electroceramic materials BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} and BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} for their ability to detect H{sub 2}O and H{sub 2}S, respectively. This report focuses on the properties and gas sensing characteristics of BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} (Y-doped BaZrO{sub 3}), as significant difficulties were encounter in generating BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} sensors. Significant new results were achieved for Y-doped BaZrO{sub 3}, including

  2. In Situ Observation of High Temperature Creep Behavior During Annealing of Steel

    NASA Astrophysics Data System (ADS)

    Zhang, X. F.; Terasaki, H.; Komizo, Y.; Murakami, Y.; Yasuda, K.

    2012-12-01

    Previous studies on creep suggested a close relationship between polycrystal grain size, substructure, and creep rate. At present, however, our understanding of the influence of polycrystal grain size, substructure, and thermal stress on creep deformation behavior seems rather insufficient, especially as there is a general lack of in situ data on structural changes during creep. In this study, the effects of thermal stress, austenite grain size, and cooling rate on slip deformations in C-Mn-Al steel during annealing were investigated systematically on the basis of in situ observations using high temperature laser scanning confocal microscopy. Finally, a kinetics model based on thermal expansion anisotropy and temperature difference was developed to explain these interesting experimental results. The in situ investigation of slip deformation during annealing greatly contributes to the understanding of high temperature creep behavior.

  3. Sealed rotors for in situ high temperature high pressure MAS NMR

    DOE PAGESBeta

    Hu, Jian Z.; Hu, Mary Y.; Zhao, Zhenchao; Xu, Souchang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M.; Peden, Charles H. F.; Lercher, Johannes A.

    2015-07-06

    Magic angle spinning (MAS) nuclear magnetic resonance (NMR) investigations on heterogeneous samples containing solids, semi-solids, liquid and gases or a mixture of them under non-conventional conditions of a combined high pressure and high temperature, or cold temperature suffer from the unavailability of a perfectly sealed rotor. Here, we report the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are easy to use and are suitable for operation temperatures from below 0 to 250 °C and pressures up to 100 bar. As an example of potential applications we performed in situ MAS NMR investigations of AlPO₄-5 molecular sieve crystallization,more » a kinetic study of the cyclohexanol dehydration reaction using 13C MAS NMR, and an investigation of the metabolomics of intact biological tissue at low temperature using 1H HR-MAS NMR spectroscopy. The in situ MAS NMR experiments performed using the reported rotors allowed reproduction of the results from traditional batch reactions, while offering more detailed quantitative information at the molecular level, as demonstrated for the molecular sieve synthesis and activation energy measurements for cyclohexanol dehydration. The perfectly sealed rotor also shows promising application for metabolomics studies using 1H HR-MAS NMR.« less

  4. Sealed rotors for in situ high temperature high pressure MAS NMR

    SciTech Connect

    Hu, Jian Z.; Hu, Mary Y.; Zhao, Zhenchao; Xu, Souchang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M.; Peden, Charles H. F.; Lercher, Johannes A.

    2015-07-06

    Magic angle spinning (MAS) nuclear magnetic resonance (NMR) investigations on heterogeneous samples containing solids, semi-solids, liquid and gases or a mixture of them under non-conventional conditions of a combined high pressure and high temperature, or cold temperature suffer from the unavailability of a perfectly sealed rotor. Here, we report the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are easy to use and are suitable for operation temperatures from below 0 to 250 °C and pressures up to 100 bar. As an example of potential applications we performed in situ MAS NMR investigations of AlPO₄-5 molecular sieve crystallization, a kinetic study of the cyclohexanol dehydration reaction using 13C MAS NMR, and an investigation of the metabolomics of intact biological tissue at low temperature using 1H HR-MAS NMR spectroscopy. The in situ MAS NMR experiments performed using the reported rotors allowed reproduction of the results from traditional batch reactions, while offering more detailed quantitative information at the molecular level, as demonstrated for the molecular sieve synthesis and activation energy measurements for cyclohexanol dehydration. The perfectly sealed rotor also shows promising application for metabolomics studies using 1H HR-MAS NMR.

  5. INTEGRATION OF HIGH TEMPERATURE GAS REACTORS WITH IN SITU OIL SHALE RETORTING

    SciTech Connect

    Eric P. Robertson; Michael G. McKellar; Lee O. Nelson

    2011-05-01

    This paper evaluates the integration of a high-temperature gas-cooled reactor (HTGR) to an in situ oil shale retort operation producing 7950 m3/D (50,000 bbl/day). The large amount of heat required to pyrolyze the oil shale and produce oil would typically be provided by combustion of fossil fuels, but can also be delivered by an HTGR. Two cases were considered: a base case which includes no nuclear integration, and an HTGR-integrated case.

  6. In situ observation and measurement of composites subjected to extremely high temperature

    NASA Astrophysics Data System (ADS)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  7. In situ proton irradiation-induced creep at very high temperature

    NASA Astrophysics Data System (ADS)

    Campbell, Anne A.; Was, Gary S.

    2013-02-01

    This objective of this work was to develop an experimental facility that can perform in situ high temperature proton irradiation-induced creep experiments on a range of materials. This was achieved by designing an irradiation chamber and stage that allows for load application and removal, provides a method for controlling and monitoring temperature and proton flux, and a means to make in situ measurement of dimensional change of the samples during the experiment. Initial experiments on POCO Graphite Inc. ZXF-5Q grade ultra-fine grain samples irradiated at 1000 °C at a damage rate of 1.15 × 10-6 dpa/s exhibited a linear dependence of measured creep rate on applied stress over a range of stresses from 10 MPa to 40 MPa.

  8. High-voltage electron microscope high-temperature in situ straining experiments to study dislocation dynamics in intermetallics and quasicrystals.

    PubMed

    Messerschmidt, U

    2001-07-01

    The dynamic behaviour of dislocations in several intermetallic alloys, studied by in situ straining experiments in a high-voltage electron microscope, is compared at room temperature and at high temperatures. In contrast to room temperature, the dislocations move viscously at high temperatures, which is explained by diffusion processes in the dislocation cores. In quasicrystals, the viscous dislocation motion can be interpreted by models on the cluster scale. PMID:11454156

  9. Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2000-01-01

    A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.

  10. High-sensitivity in situ QCLAS-based ammonia concentration sensor for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Peng, W. Y.; Sur, R.; Strand, C. L.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

    2016-07-01

    A novel quantum cascade laser (QCL) absorption sensor is presented for high-sensitivity in situ measurements of ammonia (hbox {NH}_3) in high-temperature environments, using scanned wavelength modulation spectroscopy (WMS) with first-harmonic-normalized second-harmonic detection (scanned WMS-2 f/1 f) to neutralize the effect of non-absorption losses in the harsh environment. The sensor utilized the sQ(9,9) transition of the fundamental symmetric stretch band of hbox {NH}_3 at 10.39 {\\upmu }hbox {m} and was sinusoidally modulated at 10 kHz and scanned across the peak of the absorption feature at 50 Hz, leading to a detection bandwidth of 100 Hz. A novel technique was used to select an optimal WMS modulation depth parameter that reduced the sensor's sensitivity to spectral interference from hbox {H}_2hbox {O} and hbox {CO}_2 without significantly sacrificing signal-to-noise ratio. The sensor performance was validated by measuring known concentrations of hbox {NH}_3 in a flowing gas cell. The sensor was then demonstrated in a laboratory-scale methane-air burner seeded with hbox {NH}_3, achieving a demonstrated detection limit of 2.8 ± 0.26 ppm hbox {NH}_3 by mole at a path length of 179 cm, equivalence ratio of 0.6, pressure of 1 atm, and temperatures of up to 600 K.

  11. Deformation at ambient and high temperature of in situ Laves phases-ferrite composites

    NASA Astrophysics Data System (ADS)

    Donnadieu, Patricia; Pohlmann, Carsten; Scudino, Sergio; Blandin, Jean-Jacques; Babu Surreddi, Kumar; Eckert, Jürgen

    2014-06-01

    The mechanical behavior of a Fe80Zr10Cr10 alloy has been studied at ambient and high temperature. This Fe80Zr10Cr10 alloy, whoose microstructure is formed by alternate lamellae of Laves phase and ferrite, constitutes a very simple example of an in situ CMA phase composite. The role of the Laves phase type was investigated in a previous study while the present work focuses on the influence of the microstructure length scale owing to a series of alloys cast at different cooling rates that display microstructures with Laves phase lamellae width ranging from ˜50 nm to ˜150 nm. Room temperature compression tests have revealed a very high strength (up to 2 GPa) combined with a very high ductility (up to 35%). Both strength and ductility increase with reduction of the lamella width. High temperature compression tests have shown that a high strength (900 MPa) is maintained up to 873 K. Microstructural study of the deformed samples suggests that the confinement of dislocations in the ferrite lamellae is responsible for strengthening at both ambient and high temperature. The microstructure scale in addition to CMA phase structural features stands then as a key parameter for optimization of mechanical properties of CMA in situ composites.

  12. High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages.

    PubMed

    Baek, Seung Bin; Moon, Dohyun; Graf, Robert; Cho, Woo Jong; Park, Sung Woo; Yoon, Tae-Ung; Cho, Seung Joo; Hwang, In-Chul; Bae, Youn-Sang; Spiess, Hans W; Lee, Hee Cheon; Kim, Kwang S

    2015-11-17

    Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π-π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use. PMID:26578758

  13. High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

    PubMed Central

    Baek, Seung Bin; Moon, Dohyun; Graf, Robert; Cho, Woo Jong; Park, Sung Woo; Yoon, Tae-Ung; Cho, Seung Joo; Hwang, In-Chul; Bae, Youn-Sang; Spiess, Hans W.; Lee, Hee Cheon; Kim, Kwang S.

    2015-01-01

    Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use. PMID:26578758

  14. Continuous high temperature gradient solidification of in situ Cu-Nb alloys for large scale development

    SciTech Connect

    LeHuy, H.; Fihey, J.L.; Foner, S.; Roberge, R.

    1982-01-01

    Several research groups are evaluating various scale-up approaches for the in situ technique of preparing multiply-connected Nb/sub 3/Sn composite superconducting wire. Previously, the authors developed an arrangement for continuous high temperature gradient solidification, and now have upgraded the process to permit the solidification of larger diameter (9.5 mm) rods in virtually unlimited lengths. The preparation, the microstructure, and the characteristics (solidification rate, dendrite branching, and dendrite size) are given for three directionally solidified in situ materials with a nominal composition of Cu-30 wt% Nb. Micrographs of variously extracted Nb filaments and various-order dendrites are provided. The HTGS technique offers several advantages over other scale-up production methods, such as the control over the microstructure, form, and size of the Nb dendrites. A critical current density of 10 kA/cm/sup 2/ at roughly 16.5 T has been measured for the fine dendrite materials.

  15. A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures.

    PubMed

    Nonnenmann, Stephen S

    2016-02-14

    Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end. PMID:26795921

  16. A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures

    NASA Astrophysics Data System (ADS)

    Nonnenmann, Stephen S.

    2016-02-01

    Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end.

  17. In situ synthesis and characterization of uranium carbide using high temperature neutron diffraction

    NASA Astrophysics Data System (ADS)

    Reiche, H. Matthias; Vogel, Sven C.; Tang, Ming

    2016-04-01

    We investigated the formation of UCx from UO2+x and graphite in situ using neutron diffraction at high temperatures with particular focus on resolving the conflicting reports on the crystal structure of non-quenchable cubic UC2. The agents were UO2 nanopowder, which closely imitates nano grains observed in spent reactor fuels, and graphite powder. In situ neutron diffraction revealed the onset of the UO2 + 2C → UC + CO2 reaction at 1440 °C, with its completion at 1500 °C. Upon further heating, carbon diffuses into the uranium carbide forming C2 groups at the octahedral sites. This resulting high temperature cubic UC2 phase is similar to the NaCl-type structure as proposed by Bowman et al. Our novel experimental data provide insights into the mechanism and kinetics of formation of UC as well as characteristics of the high temperature cubic UC2 phase which agree with proposed rotational rehybridization found from simulations by Wen et al.

  18. In-Situ Transmission Electron Microscope High Temperature Behavior in Nanocrystalline Platinum Thin Films

    NASA Astrophysics Data System (ADS)

    Garcia, Davil; Leon, Alexander; Kumar, Sandeep

    2016-01-01

    In this work, we present a micro electro-mechanical systems (MEMS)-based in situ transmission electron microscope (TEM) experimental setup for high-temperature uniaxial tensile behavior of nanocrystalline thin films. This setup utilizes self-heating (Ohmic) to raise the temperature of thin films while applying uniaxial tensile loading using electro-thermal actuators. Self-heating is achieved by passing a high-density direct current through the specimen. We carried out a qualitative uniaxial tensile experiment on a 75-nm platinum thin film at 360 K. Temperature is estimated using COMSOL modeling. In this qualitative experiment, we observed initial grain growth followed by formation of edge serrations. We propose that grain boundary sliding coupled with grain growth is the underlying mechanism responsible for the observed behavior.

  19. Acousto-optic Imaging System for In-situ Measurement of the High Temperature Distribution in Micron-size Specimens

    NASA Astrophysics Data System (ADS)

    Machikhin, Alexander S.; Zinin, Pavel V.; Shurygin, Alexander V.

    We developed a unique acousto-optic imaging system for in-situ measurement of high temperature distribution on micron-size specimens. The system was designed to measure temperature distribution inside minerals and functional material phases subjected to high pressure and high temperatures in a diamond anvil cell (DAC) heated by a high powered laser.

  20. In-situ high temperature irradiation setup for temperature dependent structural studies of materials under swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Kulriya, P. K.; Kumari, Renu; Kumar, Rajesh; Grover, V.; Shukla, R.; Tyagi, A. K.; Avasthi, D. K.

    2015-01-01

    An in-situ high temperature (1000 K) setup is designed and installed in the materials science beam line of superconducting linear accelerator at the Inter-University Accelerator Centre (IUAC) for temperature dependent ion irradiation studies on the materials exposed with swift heavy ion (SHI) irradiation. The Gd2Ti2O7 pyrochlore is irradiated using 120 MeV Au ion at 1000 K using the high temperature irradiation facility and characterized by ex-situ X-ray diffraction (XRD). Another set of Gd2Ti2O7 samples are irradiated with the same ion beam parameter at 300 K and simultaneously characterized using in-situ XRD available in same beam line. The XRD studies along with the Raman spectroscopic investigations reveal that the structural modification induced by the ion irradiation is strongly dependent on the temperature of the sample. The Gd2Ti2O7 is readily amorphized at an ion fluence 6 × 1012 ions/cm2 on irradiation at 300 K, whereas it is transformed to a radiation-resistant anion-deficient fluorite structure on high temperature irradiation, that amorphized at ion fluence higher than 1 × 1013 ions/cm2. The temperature dependent ion irradiation studies showed that the ion fluence required to cause amorphization at 1000 K irradiation is significantly higher than that required at room temperature irradiation. In addition to testing the efficiency of the in-situ high temperature irradiation facility, the present study establishes that the radiation stability of the pyrochlore is enhanced at higher temperatures.

  1. In situ analysis of texture development from sinusoidal stress at high pressure and temperature.

    PubMed

    Li, Li; Weidner, Donald J

    2015-12-01

    Here, we present a new experimental protocol to investigate the relationship between texture, plastic strain, and the mechanisms of plastic deformation at high pressure and temperature. The method utilizes synchrotron X-ray radiation as the probing tool, coupled with a large-volume high pressure deformation device (D-DIA). The intensity of X-ray diffraction peaks within the spectrum of the sample is used for sampling texture development in situ. The unique feature of this study is given by the sinusoidal variation of the intensity when a sinusoidal strain is applied to the sample. For a sample of magnesium oxide at elevated pressure and temperature, we demonstrate observations that are consistent with elasto-plastic models for texture development and for diffraction-peak measurements of apparent stress. The sinusoidal strain magnitude was 3%. PMID:26724072

  2. In situ analysis of texture development from sinusoidal stress at high pressure and temperature

    SciTech Connect

    Li, Li; Weidner, Donald J.

    2015-12-15

    Here, we present a new experimental protocol to investigate the relationship between texture, plastic strain, and the mechanisms of plastic deformation at high pressure and temperature. The method utilizes synchrotron X-ray radiation as the probing tool, coupled with a large-volume high pressure deformation device (D-DIA). The intensity of X-ray diffraction peaks within the spectrum of the sample is used for sampling texture development in situ. The unique feature of this study is given by the sinusoidal variation of the intensity when a sinusoidal strain is applied to the sample. For a sample of magnesium oxide at elevated pressure and temperature, we demonstrate observations that are consistent with elasto-plastic models for texture development and for diffraction-peak measurements of apparent stress. The sinusoidal strain magnitude was 3%.

  3. In situ analysis of texture development from sinusoidal stress at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Li, Li; Weidner, Donald J.

    2015-12-01

    Here, we present a new experimental protocol to investigate the relationship between texture, plastic strain, and the mechanisms of plastic deformation at high pressure and temperature. The method utilizes synchrotron X-ray radiation as the probing tool, coupled with a large-volume high pressure deformation device (D-DIA). The intensity of X-ray diffraction peaks within the spectrum of the sample is used for sampling texture development in situ. The unique feature of this study is given by the sinusoidal variation of the intensity when a sinusoidal strain is applied to the sample. For a sample of magnesium oxide at elevated pressure and temperature, we demonstrate observations that are consistent with elasto-plastic models for texture development and for diffraction-peak measurements of apparent stress. The sinusoidal strain magnitude was 3%.

  4. An experimental system for high temperature X-ray diffraction studies with in situ mechanical loading

    PubMed Central

    Oswald, Benjamin B.; Schuren, Jay C.; Pagan, Darren C.; Miller, Matthew P.

    2013-01-01

    An experimental system with in situ thermomechanical loading has been developed to enable high energy synchrotron x-ray diffraction studies of crystalline materials. The system applies and maintains loads of up to 2250 N in uniaxial tension or compression at a frequency of up to 100 Hz. The furnace heats the specimen uniformly up to a maximum temperature of 1200 °C in a variety of atmospheres (oxidizing, inert, reducing) that, combined with in situ mechanical loading, can be used to mimic processing and operating conditions of engineering components. The loaded specimen is reoriented with respect to the incident beam of x-rays using two rotational axes to increase the number of crystal orientations interrogated. The system was used at the Cornell High Energy Synchrotron Source to conduct experiments on single crystal silicon and polycrystalline Low Solvus High Refractory nickel-based superalloy. The data from these experiments provide new insights into how stresses evolve at the crystal scale during thermomechanical loading and complement the development of high-fidelity material models. PMID:23556825

  5. Molecular Tagging Velocimetry Development for In-situ Measurement in High-Temperature Test Facility

    NASA Technical Reports Server (NTRS)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2015-01-01

    The High Temperature Test Facility, HTTF, at Oregon State University (OSU) is an integral-effect test facility designed to model the behavior of a Very High Temperature Gas Reactor (VHTR) during a Depressurized Conduction Cooldown (DCC) event. It also has the ability to conduct limited investigations into the progression of a Pressurized Conduction Cooldown (PCC) event in addition to phenomena occurring during normal operations. Both of these phenomena will be studied with in-situ velocity field measurements. Experimental measurements of velocity are critical to provide proper boundary conditions to validate CFD codes, as well as developing correlations for system level codes, such as RELAP5 (http://www4vip.inl.gov/relap5/). Such data will be the first acquired in the HTTF and will introduce a diagnostic with numerous other applications to the field of nuclear thermal hydraulics. A laser-based optical diagnostic under development at The George Washington University (GWU) is presented; the technique is demonstrated with velocity data obtained in ambient temperature air, and adaptation to high-pressure, high-temperature flow is discussed.

  6. In-Situ Ultrafast 3D Imaging of Magma Vesiculation at High Temperature

    NASA Astrophysics Data System (ADS)

    Ulmer, P.; Pistone, M.; Caricchi, L.; Fife, J.; Marone, F.; Benson, P. M.; Almqvist, B.; Reusser, E.; Rust, A.; Burlini, L.

    2011-12-01

    We present new experimental results on magma vesiculation at high temperature. We investigated the processes of volatile exsolution (nucleation, growth and coalescence of gas bubbles) in magmas by performing in-situ high-temperature and ambient pressure experiments. Samples were heated with a newly-commissioned class 4 laser system and manual control. Simultaneously, the evolving 3D structure was captured by ultrafast synchrotron based X-ray tomographic microscopy (pixel size of 2.9 microns; 1 complete tomographic dataset acquired in 1 s), performed at the TOMCAT beam-line at Swiss Light Source (PSI, Villigen, Switzerland). Hydrous crystal- and bubble-free magmatic glasses liable to vesiculate at high temperature (400-1100 °C) were employed for the experiments. The samples used were cylindrical cores (2 mm in diameter and 2 mm in length), drilled from natural samples of obsidian (from: Lipari Island, Italy; Mayor Island, New Zealand; Tenerife Island, Spain; Little Glass Mountain, USA), containing different amounts of water (less than 1 wt%). These were chosen to represent a range of different physical properties (i.e., viscosity) as function of increasing temperature, due to their specific chemical compositions and, in particular, water content in the starting glass (measured via Karl Fischer titration). We observed the development of four different kinds of 3D microstructures during in-situ high-temperature experiments, depending on the starting material employed: (1) low vesicularity (40 vol%) with a narrow range in size of bubbles, which are generally spherical; (2) high vesicularity (80 vol%), showing a range of bubble sizes, shapes and extent of coalescence; (3) high vesicularity (85 vol%) and a polyhedral cell network (similar to reticulites); (4) a single expanding bubble. No magma fragmentation occurred in any of the experiments performed; we noticed different degrees of vertical thermal expansion, mainly depending on the amount of bubbles generated during

  7. High Temperature In Situ Compression of Thermoplastically Formed Nano-scale Metallic Glass

    NASA Astrophysics Data System (ADS)

    Mridha, Sanghita; Arora, Harpreet Singh; Lefebvre, Joseph; Bhowmick, Sanjit; Mukherjee, Sundeep

    2016-05-01

    The mechanical behavior of nano-scale metallic glasses was investigated by in situ compression tests in a scanning electron microscope. Platinum-based metallic glass nano-pillars were fabricated by thermoplastic forming. The nano-pillars and corresponding bulk substrate were tested in compression over the range of room temperature to glass transition. Stress-strain curves of the nano-pillars were obtained along with in situ observation of their deformation behavior. The bulk substrate as well as nano-pillars showed an increase in elastic modulus with temperature which is explained by diffusive rearrangement of atomic-scale viscoelastic units.

  8. Strontium titanate (100) surfaces monitoring by high temperature in situ ellipsometry

    NASA Astrophysics Data System (ADS)

    Hrabovsky, D.; Berini, B.; Fouchet, A.; Aureau, D.; Keller, N.; Etcheberry, A.; Dumont, Y.

    2016-03-01

    We report monitoring and analysis of the contamination overlayer on the surface of different SrTiO3 (STO) substrates by in situ spectroscopic ellipsometry (SE) and ex situ X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Substrates of STO with different terminations, random and TiO2 terminated, were heated from room temperature up to 720 °C under oxygen pressure in UHV chamber similar to conditions commonly used for epitaxial growth of perovskite oxides. Contamination layer on the substrate was modeled as an equivalent dielectric overlayer with a thickness of 2 nm at room temperature which decreases progressively during the heating up to reach its minimum (around 1 unit cell) at the temperature around 550 °C. After exposition to air, surface recovers a contamination layer on both types of substrates (with random termination and TiO2 termination). XPS analysis confirmed that water and carbon dioxide as adventitious carbon species present in air are chemically adsorbed on the STO surface, providing evidence of desorption process which persists until 550 °C. This condition is an important issue in order to obtain clean controlled interface between STO and deposited film for low temperature growth as for instance atomic layer deposition and integration of STO buffer layer on silicon. In situ SE commonly present in thin layer deposition systems is a powerful tool to monitor in situ surface contamination and decontamination temperature as it can be performed in situ even in operando.

  9. In Situ Measurements of Spectral Emissivity of Materials for Very High Temperature Reactors

    SciTech Connect

    G. Cao; S. J. Weber; S. O. Martin; T. L. Malaney; S. R. Slattery; M. H. Anderson; K. Sridharan; T. R. Allen

    2011-08-01

    An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed. The facility is capable of measuring emissivities of seven materials in a single experiment, thereby enhancing the accuracy in measurements due to even minor systemic variations in temperatures and environments. The system consists of a cylindrical silicon carbide (SiC) block with seven sample cavities and a deep blackbody cavity, a detailed optical system, and a Fourier transform infrared spectrometer. The reliability of the facility has been confirmed by comparing measured spectral emissivities of SiC, boron nitride, and alumina (Al2O3) at 600 C against those reported in literature. The spectral emissivities of two candidate alloys for VHTR, INCONEL{reg_sign} alloy 617 (INCONEL is a registered trademark of the Special Metals Corporation group of companies) and SA508 steel, in air environment at 700 C were measured.

  10. Sealed rotors for in situ high temperature high pressure MAS NMR.

    PubMed

    Hu, Jian Zhi; Hu, Mary Y; Zhao, Zhenchao; Xu, Suochang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M; Peden, Charles H F; Lercher, Johannes A

    2015-09-11

    Here we present the design of reusable and perfectly sealed all-zirconia MAS rotors. The rotors are used to study AlPO4-5 molecular sieve crystallization under hydrothermal conditions, high temperature high pressure cyclohexanol dehydration reaction, and low temperature metabolomics of intact biological tissue. PMID:26171928

  11. Sealed Rotors for In Situ High Temperature High Pressure MAS NMR†

    PubMed Central

    Hu, Jian Zhi; Hu, Mary Y.; Zhao, Zhenchao; Xu, Suochang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M.; Peden, Charles H. F.; Lercher, Johannes A.

    2015-01-01

    Here we present the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are used to study AlPO4-5 molecular sieve crystallization under hydrothermal conditions, high temperature high pressure cyclohexanol dehydration reaction, and low temperature metabolomics of intact biological tissue. PMID:26171928

  12. Additive Manufacturing of Reactive In Situ Zr Based Ultra-High Temperature Ceramic Composites

    NASA Astrophysics Data System (ADS)

    Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

    2016-03-01

    Reactive in situ multi-material additive manufacturing of ZrB2-based ultra-high-temperature ceramics in a Zr metal matrix was demonstrated using LENS™. Sound metallurgical bonding was achieved between the Zr metal and Zr-BN composites with Ti6Al4V substrate. Though the feedstock Zr power had α phase, LENS™ processing of the Zr powder and Zr-BN premix powder mixture led to the formation of some β phase of Zr. Microstructure of the Zr-BN composite showed primary grains of zirconium diboride phase in zirconium metal matrix. The presence of ZrB2 ceramic phase was confirmed by X-ray diffraction (XRD) analysis. Hardness of pure Zr was measured as 280 ± 12 HV and, by increasing the BN content in the feedstock, the hardness was found to increase. In Zr-5%BN composite, the hardness was 421 ± 10 HV and the same for Zr-10%BN composite was 562 ± 10 HV. It is envisioned that such multi-materials additive manufacturing will enable products in the future that cannot be manufactured using traditional approaches particularly in the areas of high-temperature metal-ceramic composites with compositional and functional gradation.

  13. In situ Expression of Functional Genes Reveals Nitrogen Cycling at High Temperatures in Terrestrial Hydrothermal Systems

    NASA Astrophysics Data System (ADS)

    Loiacono, S. T.; Meyer-Dombard, D. R.

    2011-12-01

    An essential element for life, nitrogen occurs in all living organisms and is critical for the synthesis of amino acids, proteins, nucleic acids, and other forms of biomass. Thus, nitrogen cycling likely plays a vital role in microbial metabolic processes as well as nutrient availability. For microorganisms in "extreme" environments, this means developing adaptations that allow them to survive in harsh conditions and still perform the metabolisms essential to sustain life. Recent studies have screened biofilms and thermal sediments of Yellowstone National Park (YNP) thermal features for the presence of nifH genes, which code for a key enzyme in the nitrogen fixation process [1-4]. Furthermore, analysis of nitrogen isotopes in biofilms across a temperature and chemical gradient revealed that nitrogen fixation likely varies across the chemosynthetic/photosynthetic ecotone [5]. Although research has evaluated and confirmed the presence of nifH genes in various thermophilic microbial communities, the existence of a gene in the DNA of an organism does not verify its use. Instead, other methods, such as culturing, isotope tracer assays, and gene expression studies are required to provide direct evidence of biological nitrogen fixation. Culturing and isotope tracer approaches have successfully revealed high-temperature biological nitrogen fixation in both marine hydrothermal vent microbial communities [6] and in acidic, terrestrial hydrothermal sediment [3]. Transcriptomics-based techniques (using mRNA extracted from samples to confirm in situ expression of targeted genes) have been much more limited in number, and only a few studies have, to date, investigated in situ expression of the nifH gene in thermophilic microbial communities [2, 7]. This study explores the presence and expression of nifH genes in several features of the Lower Geyser Basin (LGB) of YNP. Nucleic acids from chemosynthetic and photosynthetic microbial communities were extracted and then amplified

  14. In situ spectroscopic investigation of hyperthermophilic metal-respiring archaea at high-temperature

    NASA Astrophysics Data System (ADS)

    Ménez, B.; Bureau, H.; Gouget, B.; Avoscan, L.; Simionovici, A.; Somogyi, A.

    2003-04-01

    The main issue of this study is developing methodologies that can improve abilities to characterize life in extreme habitats. In particular, it aims at evaluating the possibility of monitoring microorganisms mediated reactions involving metals by using non destructive X-ray microprobe combined with high pressure and temperature micro-reactors. The first step was dedicated to the study of metal-respiring organisms that achieve growth with oxyanions of arsenate and selenate as their electron acceptors for the oxidation of organic substrates or H2, forming elemental selenium or arsenite, respectively, as the reduction products. We focused on a strictly anaerobic hyperthermophilic archaea, Pyrobaculum arsenaticum, recently isolated and well adapted to high levels of arsenate and selenate (Huber et al., 2000, System. Appl. Microbiol., 23, 305). We report here the first in situ X-ray Absorption Near Edge Structure (XANES) spectroscopic characterization of the oxidation state of selenium following microbial respiration at high temperature. A Basset-modified Hydrothermal Diamond Anvil Cell (HDAC) acts as anaerobic micro-reactor to reproduce extreme temperature and pressure conditions for life and allows, together with the direct visual observation of the organisms, the microbeam characterization of the changes of metal concentration and speciation induced by microbial activity. The measurements were performed at the ESRF on undulator beamline ID22. P. arsenaticum together with its culture medium, doped with selenate (50 μM), were loaded under N_2 atmosphere in the HDAC. High-resolution X-ray fluorescence and selenium K-edge XANES spectra were collected alternatively and continuously at high temperature (up to 95^oC), allowing for the time-resolved monitoring of the chemical evolution of the culture medium. Data processing is still in progress. In the long-term, our aim is, on one hand, to shed light on the tolerance in terms of temperature, pressure and metal

  15. In situ measurements of high temperature growth of correlated systems: a materials by design scheme

    NASA Astrophysics Data System (ADS)

    He, Hua

    There is great interest in developing new ways to use predictive theory to accelerate materials synthesis. We have previously shown that DFT +DMFT electronic structure calculations are successful at predicting gaps and ordered moments, even when correlations are very strong.[ 1 , 2 ] Building on these results, we set out to explore an even closer integration of theory and synthesis, aiming to discover new routes for doping Mott insulators and producing new superconductors. In situ high temperature high energy X-ray diffraction is used to determine the crystal structures of compounds just as they form from the growths, and the structural information is used as input for DFT +DMFT calculations that predict functionality, closing the synthesis loop by suggesting productive new directions. Using this approach, we have investigated the transition metal oxysulfide system Ba-Co-S-O and successfully discovered the new compound BaCoSO, and identified it as an interesting small gap Mott insulator by DFT +DMFT calculations even before any traditional crystal growth is attempted in the lab We acknowledge the Office of Assistant Secretary of Defense for Research and Engineering for providing the NSSEFF funds that supported this research.

  16. In situ high-temperature characterization of AlN-based surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Aubert, Thierry; Bardong, Jochen; Legrani, Ouarda; Elmazria, Omar; Badreddine Assouar, M.; Bruckner, Gudrun; Talbi, Abdelkrim

    2013-07-01

    We report on in situ electrical measurements of surface acoustic wave delay lines based on AlN/sapphire structure and iridium interdigital transducers between 20 °C and 1050 °C under vacuum conditions. The devices show a great potential for temperature sensing applications. Burnout is only observed after 60 h at 1050 °C and is mainly attributed to the agglomeration phenomena undergone by the Ir transducers. However, despite the vacuum conditions, a significant oxidation of the AlN film is observed, pointing out the limitation of the considered structure at least at such extreme temperatures. Original structures overcoming this limitation are then proposed and discussed.

  17. In situ visualization of magma deformation at high temperature using time-lapse 3D tomography

    NASA Astrophysics Data System (ADS)

    Godinho, jose; Lee, Peter; Lavallee, Yan; Kendrick, Jackie; Von-Aulock, Felix

    2016-04-01

    We use synchrotron based x-ray computed micro-tomography (sCT) to visualize, in situ, the microstructural evolution of magma samples 3 mm diameter with a resolution of 3 μm during heating and uniaxial compression at temperatures up to 1040 °C. The interaction between crystals, melt and gas bubbles is analysed in 4D (3D + time) during sample deformation. The ability to observe the changes of the microstructure as a function of time allow us to: a) study the effect of temperature in the ability of magma to fracture or deform; b) quantify bubble nucleation and growth rates during heating; c) study the relation between crystal displacement and volatile exsolution. We will show unique beautiful videos of how bubbles grow and coalescence, how samples and crystals within the sample fracture, heal and deform. Our study establishes in situ sCT as a powerful tool to quantify and visualize with micro-scale resolution fast processes taking place in magma that are essential to understand ascent in a volcanic conduit and validate existing models for determining the explosivity of volcanic eruptions. Tracking simultaneously the time and spatial changes of magma microstructures is shown to be primordial to study disequilibrium processes between crystals, melt and gas phases.

  18. Use of Atomic Layer Deposition to Improve the Stability of Silver Substrates for In-Situ, High Temperature SERS Measurements

    SciTech Connect

    John, Joshy; Mahurin, Shannon Mark; Dai, Sheng; Sepaniak, Michael

    2010-01-01

    A method to stabilize silver surface-enhanced Raman spectroscopy (SERS) substrates for in-situ, high temperature applications is demonstrated. Silver island films grown by thermal evaporation were coated with a thin layer (from 2.5nm to 5nm) of alumina by atomic layer deposition (ALD), which protects and stabilizes the SERS-active substrate without eliminating the Raman enhancement. The temporal stability of the alumina-coated silver island films was examined by measurement of the Raman intensity of rhodamine 6G molecules deposited onto bare and alumina-coated silver substrates over the course of thirty-four days. The coated substrates showed almost no change in SERS enhancement while the uncoated substrates exhibited a significant decrease in Raman intensity. To demonstrate the feasibility of the alumina-coated silver substrate as a probe of adsorbates and reactions at elevated temperatures, an in-situ SERS measurement of calcium nitrate tetrahydrate on bare and alumina-coated silver was performed at temperatures ranging from 25 C to 400 C. ALD deposition of an ultrathin alumina layer significantly improved the thermal stability of the SERS substrate thus enabling in-situ detection of the dehydration of the calcium nitrate tetrahydrate at elevated temperature. Despite some loss of Raman signal, the coated substrate exhibited greater thermal stability compared to the uncoated substrate. These experiments show that ALD can be used to synthesize stable SERS substrates capable of measuring adsorbates and processes at high temperature.

  19. High-pressure cell for neutron diffraction with in situ pressure control at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Jacobsen, Matthew K.; Ridley, Christopher J.; Bocian, Artur; Kirichek, Oleg; Manuel, Pascal; Khalyavin, Dmitry; Azuma, Masaki; Attfield, J. Paul; Kamenev, Konstantin V.

    2014-04-01

    Pressure generation at cryogenic temperatures presents a problem for a wide array of experimental techniques, particularly neutron studies due to the volume of sample required. We present a novel, compact pressure cell with a large sample volume in which load is generated by a bellow. Using a supply of helium gas up to a pressure of 350 bar, a load of up to 78 kN is generated with leak-free operation. In addition, special fiber ports added to the cryogenic center stick allow for in situ pressure determination using the ruby pressure standard. Mechanical stability was assessed using finite element analysis and the dimensions of the cell have been optimized for use with standard cryogenic equipment. Load testing and on-line experiments using NaCl and BiNiO3 have been done at the WISH instrument of the ISIS pulsed neutron source to verify performance.

  20. High-pressure cell for neutron diffraction with in situ pressure control at cryogenic temperatures

    SciTech Connect

    Jacobsen, Matthew K.; Ridley, Christopher J.; Bocian, Artur; Kamenev, Konstantin V.; Kirichek, Oleg; Manuel, Pascal; Khalyavin, Dmitry; Azuma, Masaki; Attfield, J. Paul

    2014-04-15

    Pressure generation at cryogenic temperatures presents a problem for a wide array of experimental techniques, particularly neutron studies due to the volume of sample required. We present a novel, compact pressure cell with a large sample volume in which load is generated by a bellow. Using a supply of helium gas up to a pressure of 350 bar, a load of up to 78 kN is generated with leak-free operation. In addition, special fiber ports added to the cryogenic center stick allow for in situ pressure determination using the ruby pressure standard. Mechanical stability was assessed using finite element analysis and the dimensions of the cell have been optimized for use with standard cryogenic equipment. Load testing and on-line experiments using NaCl and BiNiO{sub 3} have been done at the WISH instrument of the ISIS pulsed neutron source to verify performance.

  1. In situ X-ray ptychography imaging of high-temperature CO{sub 2} acceptor particle agglomerates

    SciTech Connect

    Høydalsvik, Kristin; Bø Fløystad, Jostein; Esmaeili, Morteza; Mathiesen, Ragnvald H.; Breiby, Dag W.; Zhao, Tiejun; Rønning, Magnus; Diaz, Ana; Andreasen, Jens W.

    2014-06-16

    Imaging nanoparticles under relevant reaction conditions of high temperature and gas pressure is difficult because conventional imaging techniques, like transmission electron microscopy, cannot be used. Here we demonstrate that the coherent diffractive imaging technique of X-ray ptychography can be used for in situ phase contrast imaging in structure studies at atmospheric pressure and elevated temperatures. Lithium zirconate, a candidate CO{sub 2} capture material, was studied at a pressure of one atmosphere in air and in CO{sub 2}, at temperatures exceeding 600 °C. Images with a spatial resolution better than 200 nm were retrieved, and possibilities for improving the experiment are described.

  2. High temperature in-situ observations of multi-segmented metal nanowires encapsulated within carbon nanotubes by in-situ filling technique

    PubMed Central

    2012-01-01

    Multi-segmented one-dimensional metal nanowires were encapsulated within carbon nanotubes (CNTs) through in-situ filling technique during plasma-enhanced chemical vapor deposition process. Transmission electron microscopy (TEM) and environmental TEM were employed to characterize the as-prepared sample at room temperature and high temperature. The selected area electron diffractions revealed that the Pd4Si nanowire and face-centered-cubic Co nanowire on top of the Pd nanowire were encapsulated within the bottom and tip parts of the multiwall CNT, respectively. Although the strain-induced deformation of graphite walls was observed, the solid-state phases of Pd4Si and Co-Pd remain even at above their expected melting temperatures and up to 1,550 ± 50°C. Finally, the encapsulated metals were melted and flowed out from the tip of the CNT after 2 h at the same temperature due to the increase of internal pressure of the CNT. PMID:22873841

  3. In-situ electrochemical study of Zr1nb alloy corrosion in high temperature Li+ containing water

    NASA Astrophysics Data System (ADS)

    Krausová, Aneta; Macák, Jan; Sajdl, Petr; Novotný, Radek; Renčiuková, Veronika; Vrtílková, Věra

    2015-12-01

    Long-term in-situ corrosion tests were performed in order to evaluate the influence of lithium ions on the corrosion of zirconium alloy. Experiments were carried out in a high-pressure high-temperature loop (280 °C, 8 MPa) in a high concentration water solution of LiOH (70 and 200 ppm Li+) and in a simulated WWER primary coolant environment. The kinetic parameters characterising the oxidation process have been explored using in-situ electrochemical impedance spectroscopy and slow potentiodynamic polarization. Also, a suitable equivalent circuit was suggested, which would approximate the impedance characteristics of the corrosion of Zr-1Nb alloy. The Mott-Schottky approach was used to determine the semiconducting character of the passive film.

  4. In situ high-temperature infrared emissivity spectroscopy of silicate glasses and glass-ceramics

    NASA Astrophysics Data System (ADS)

    Santos, Cristiane N.; de Sousa Meneses, Domingos; Montouillout, Valerie; Echegut, Patrick

    2011-03-01

    Glasses and glass-ceramics are materials of widespread application in industry, building, photonics, microelectronics and medicine. Glass-ceramics are obtained by controlled glass crystallization, and many efforts have been done in the last years to better understand the structural changes occurring in this process. Here we show that in situ infrared emissivity spectroscopy is also a suitable technique for this purpose and a wide spectral and temperature range could be accessed (25-16000 cm-1 and 400-1700 K, respectively). We use a home-made instrument composed of two spectrometers, and a CO2 laser for locally heat the glass samples up to the melt. A dielectric function model was applied to fit the experimental data and compute the materials optical properties. We show that using new decomposition procedure quantitative information on the distribution of the Qn tetrahedral units (n being the number of bridging oxygen) can be obtained. The results at room temperature are in good agreement with recent molecular dynamics simulations. The major changes occur during quartz crystallization, with a remarkable increase of Q4 units. Supported by ANR Postre.

  5. In situ high-temperature X-ray diffraction characterization of yttrium-implanted extra low-carbon steel

    SciTech Connect

    Caudron, E.; Buscail, H.; Perrier, S.

    1999-11-01

    Yttrium-implanted and unimplanted extra low-carbon steel samples were analyzed at T = 700 C and under an oxygen partial pressure P{sub O2} = 0.041Pa for 24 h to show the yttrium implantation effect on extra low-carbon steel high-temperature corrosion resistance. Sample oxidation weight gains were studied by thermogravimetry, and structural analyses were performed using in situ high-temperature X-ray diffraction with the same experimental conditions. The aim of this paper is to show the initial nucleation stage of the main compounds induced by oxidation at high temperatures according to the initial sample treatment (yttrium-implanted or unimplanted). The results obtained by in situ high-temperature X-ray diffraction will be compared to those by thermogravimetry to show the existing correlation between weight gain curves and structural studies. Results allow one to understand the improved corrosion resistance of yttrium-implanted extra low-carbon steel at high temperatures.

  6. Crystal structure of a high-pressure/high-temperature phase of alumina by in situ X-ray diffraction.

    PubMed

    Lin, Jung-Fu; Degtyareva, Olga; Prewitt, Charles T; Dera, Przemyslaw; Sata, Nagayoshi; Gregoryanz, Eugene; Mao, Ho-Kwang; Hemley, Russell J

    2004-06-01

    Alumina (alpha-Al(2)O(3)) has been widely used as a pressure calibrant in static high-pressure experiments and as a window material in dynamic shock-wave experiments; it is also a model material in ceramic science. So understanding its high-pressure stability and physical properties is crucial for interpreting such experimental data, and for testing theoretical calculations. Here we report an in situ X-ray diffraction study of alumina (doped with Cr(3+)) up to 136 GPa and 2,350 K. We observe a phase transformation that occurs above 96 GPa and at high temperatures. Rietveld full-profile refinements show that the high-pressure phase has the Rh(2)O(3) (II) (Pbcn) structure, consistent with theoretical predictions. This phase is structurally related to corundum, but the AlO(6) polyhedra are highly distorted, with the interatomic bond lengths ranging from 1.690 to 1.847 A at 113 GPa. Ruby luminescence spectra from Cr(3+) impurities within the quenched samples under ambient conditions show significant red shifts and broadening, consistent with the different local environments of chromium atoms in the high-pressure structure inferred from diffraction. Our results suggest that the ruby pressure scale needs to be re-examined in the high-pressure phase, and that shock-wave experiments using sapphire windows need to be re-evaluated. PMID:15146173

  7. A High Temperature Capacitive Pressure Sensor Based on Alumina Ceramic for in Situ Measurement at 600 °C

    PubMed Central

    Tan, Qiulin; Li, Chen; Xiong, Jijun; Jia, Pinggang; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Hong, Yingping; Ren, Zhong; Luo, Tao

    2014-01-01

    In response to the growing demand for in situ measurement of pressure in high-temperature environments, a high temperature capacitive pressure sensor is presented in this paper. A high-temperature ceramic material-alumina is used for the fabrication of the sensor, and the prototype sensor consists of an inductance, a variable capacitance, and a sealed cavity integrated in the alumina ceramic substrate using a thick-film integrated technology. The experimental results show that the proposed sensor has stability at 850 °C for more than 20 min. The characterization in high-temperature and pressure environments successfully demonstrated sensing capabilities for pressure from 1 to 5 bar up to 600 °C, limited by the sensor test setup. At 600 °C, the sensor achieves a linear characteristic response, and the repeatability error, hysteresis error and zero-point drift of the sensor are 8.3%, 5.05% and 1%, respectively. PMID:24487624

  8. In situ observation of crystallographic preferred orientation of deforming olivine at high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Ohuchi, Tomohiro; Nishihara, Yu; Seto, Yusuke; Kawazoe, Takaaki; Nishi, Masayuki; Maruyama, Genta; Hashimoto, Mika; Higo, Yuji; Funakoshi, Ken-ichi; Suzuki, Akio; Kikegawa, Takumi; Irifune, Tetsuo

    2015-06-01

    Simple-shear deformation experiments on polycrystalline olivine and olivine single-crystal were conducted at pressures of 1.3-3.8 GPa and temperatures of 1223-1573 K to understand the achievement of steady-state fabric strength and the process of dynamic recrystallization. Development of crystallographic preferred orientation (CPO) of olivine was evaluated from two-dimensional X-ray diffraction patterns, and shear strain was measured from X-ray radiographs. The steady-state fabric strength of the A-type fabric was achieved within total shear strain of γ = 2. At strains higher than γ = 1, an increase in concentration of the [0 1 0] axes mainly contributes to an increase in fabric strength. At strains higher than γ = 2, the magnitude of VSH/VSV (i.e., ratio of horizontally and vertically polarized shear wave velocities) scarcely increased in most of the runs. The VSH/VSV of peridotite (70 vol.% olivine + 30 vol.% minor phases) having the steady-state A-type olivine fabric coincides with that of recent global one-dimensional models under the assumption of horizontal flow, suggesting that the seismic anisotropy observed in the shallow upper mantle is mostly explained by the development of A-type olivine fabric. Experimental results on the deformation of single-crystal olivine showed that the CPO of olivine is influenced by the initial orientation of the starting single crystal because strain is concentrated in the recrystallized areas and the relic of the starting single crystal remains. In the upper mantle, the old CPO of olivine developed in the past may affect the olivine CPO developed in the present.

  9. Injection well with high-pressure, high-temperature in situ down-hole steam formation

    SciTech Connect

    Marr, A.W.

    1981-12-01

    A portion of an injection well adjacent an oil-bearing earth formation is sealed off by spaced-apart high-pressure-resistant plugs, and water is charged into the bore-hole space between the plugs at a sufficient rate to effect sustained water pressure in the range of from 400 to 25,000 psi. Under such pressure sufficient current is passed between two electrodes in the water to convert from 10 to 33 barrels of water per hour into steam.

  10. Fracture Evaluation of In-Situ Sensors for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Staroselsky, Alexander

    2003-01-01

    The feasibility of fabricating an in-situ crack sensor for real-time detection of surface cracks propagating in engine components was evaluated using a computational fracture mechanics model. The in-situ sensor system would be required to: (1) Be capable of sustaining normal function in a severe environment; (2) Transmit a signal if a detected crack in the component was above a predetermined length, but below a critical length that would lead to failure; (3) Act neutrally upon the overall performance of the engine system and not interfere with the engine maintenance operations. In this work, fracture mechanics methodologies are used to identify the requirements for an in-situ sensor system that could withstand the engine operating environment, foreign object damage, and minimally degrade engine performance. A computational fracture mechanics model was developed to evaluate the feasibility of fabricating an in-situ crack sensor for real-time damage propagation detection in engine components.

  11. In situ observation of low temperature growth of Ge on Si(1 1 1) by reflection high energy electron diffraction

    NASA Astrophysics Data System (ADS)

    Grimm, Andreas; Fissel, Andreas; Bugiel, Eberhard; Wietler, Tobias F.

    2016-05-01

    In this paper we investigate the initial stages of epitaxial growth of Ge on Si(1 1 1) and the impact of growth temperature on strain evolution in situ by reflection high energy electron diffraction (RHEED) for temperatures between 200 °C and 400 °C. The change in surface morphology from a flat wetting layer to subsequent islanding that is characteristic for Stranski-Krastanov growth is monitored by spot intensity analysis. The corresponding critical layer thickness is determined to 3.1 < dc < 3.4 ML. In situ monitoring of the strain relaxation process reveals a contribution of the Si(1 1 1) 7 × 7-surface reconstruction to the strain relaxation process. High resolution transmission electron microscopy confirms that the Ge islands exhibit a high degree of structural perfection and an ordered interfacial misfit dislocation network already at a growth temperature of 200 °C is established. The temperature dependency of island shape, density and height is characterized by atomic force microscopy and compared to the RHEED investigations.

  12. In situ characterization of catalysts and membranes in a microchannel under high-temperature water gas shift reaction conditions

    NASA Astrophysics Data System (ADS)

    Cavusoglu, G.; Dallmann, F.; Lichtenberg, H.; Goldbach, A.; Dittmeyer, R.; Grunwaldt, J.-D.

    2016-05-01

    Microreactor technology with high heat transfer in combination with stable catalysts is a very attractive approach for reactions involving major heat effects such as methane steam reforming and to some extent, also the high temperature water gas shift (WGS) reaction. For this study Rh/ceria catalysts and an ultrathin hydrogen selective membrane were characterized in situ in a microreactor specially designed for x-ray absorption spectroscopic measurements under WGS conditions. The results of these experiments can serve as a basis for further development of the catalysts and membranes.

  13. In-situ Diffraction Study of Magnetite at Simultaneous High Pressure and High Temperature Using Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Wang, L.; Zhang, J.; Wang, S.; Chen, H.; Zhao, Y.

    2014-12-01

    Magnetite intertwined with the evolution of human civilizations, and remains so today. It is technologically and scientifically important by virtue of its unique magnetic and electrical properties. Magnetite is a common mineral found in a variety of geologic environments, and plays an important role in deciphering the oxygen evolution in the Earth's atmosphere and its deep interiors. The latter application asks for the knowledge of the thermal and elastic properties of magnetite at high pressures and temperatures, which is currently not available in literature. We have carried out a few in-situ diffraction experiments on magnetite using white synchrotron radiation at beamline X17B2 of National Synchrotron Light Source (NSLS). A DIA module in an 1100-ton press and WC anvils were employed for compression, and diffraction spectra were collected at simultaneous high pressures (P) and temperatures (T) (up to 9 GPa and 900 oC). Mixture of amorphous boron and epoxy resin was used as pressure medium, and NaCl as pressure marker. Temperature was recorded by W-Re thermocouples. Commercially purchased magnetite powder and a mixture of the said powder and NaCl (1:1) were used as starting material in separate experiments. Preliminary data analyses have yielded following observations: (1) Charge disordering seen at ambient pressure remains active in current experiments, especially at lower pressures (< 6 GPa); (2) Though at each condition potentially complicated by charge disordering process, isothermal compression curves remains simple and reproducible; (3) During cooling, the reversibility and degree of cation disordering depend on the starting material and/or experimental P-T path; and (4) cation disordering notably reduces the apparent bulk moduli of magnetite.

  14. In situ biaxial rotation at low-temperatures in high magnetic fields.

    PubMed

    Selby, N S; Crawford, M; Tracy, L; Tracey, L; Reno, J L; Pan, W

    2014-09-01

    We report the design, construction, and characterization of a biaxial sample rotation stage for use in a cryogenic system for orientation-dependent studies of anisotropic electronic transport phenomena at low temperatures and high magnetic fields. Our apparatus allows for continuous rotation of a sample about two axes, both independently and simultaneously. PMID:25273781

  15. In situ biaxial rotation at low-temperatures in high magnetic fields

    SciTech Connect

    Selby, N. S.; Crawford, M.; Tracy, L.; Reno, J. L.; Pan, W.

    2014-09-15

    We report the design, construction, and characterization of a biaxial sample rotation stage for use in a cryogenic system for orientation-dependent studies of anisotropic electronic transport phenomena at low temperatures and high magnetic fields. Our apparatus allows for continuous rotation of a sample about two axes, both independently and simultaneously.

  16. In-situ Phase Transformation and Deformation of Iron at High Pressure andTemperature

    SciTech Connect

    Miyagi, Lowell; Kunz, Martin; Knight, Jason; Nasiatka, James; Voltolini, Marco; Wenk, Hans-Rudolf

    2008-07-01

    With a membrane based mechanism to allow for pressure change of a sample in aradial diffraction diamond anvil cell (rDAC) and simultaneous infra-red laser heating, itis now possible to investigate texture changes during deformation and phasetransformations over a wide range of temperature-pressure conditions. The device isused to study bcc (alpha), fcc (gamma) and hcp (epislon) iron. In bcc iron, room temperature compression generates a texture characterized by (100) and (111) poles parallel to the compression direction. During the deformation induced phase transformation to hcp iron, a subset of orientations are favored to transform to the hcp structure first and generate a texture of (01-10) at high angles to the compression direction. Upon further deformation, the remaining grains transform, resulting in a texture that obeys the Burgers relationship of (110)bcc // (0001)hcp. This is in contrast to high temperature results that indicate that texture is developed through dominant pyramidal {2-1-12}<2-1-13> and basal (0001)-{2-1-10} slip based on polycrystal plasticity modeling. We also observe that the high temperature fcc phase develops a 110 texture typical for fcc metals deformed in compression.

  17. Deformation of olivine under mantle conditions: An in situ high-pressure, high-temperature study using monochromatic synchrotron radiation

    SciTech Connect

    Hilairet, Nadège; Wang, Yanbin; Sanehira, Takeshi; Merkel, Sébastien; Mei, Shenghua

    2012-03-15

    Polycrystalline samples of San Carlos olivine were deformed at high-pressure (2.8-7.8 GPa), high-temperature (1153 to 1670 K), and strain rates between 7.10{sup -6} and 3.10{sup -5} s{sup -1}, using the D-DIA apparatus. Stress and strain were measured in situ using monochromatic X-rays diffraction and imaging, respectively. Based on the evolution of lattice strains with total bulk strain and texture development, we identified three deformation regimes, one at confining pressures below 3-4 GPa, one above 4 GPa, both below 1600 K, and one involving growth of diffracting domains associated with mechanical softening above {approx}1600 K. The softening is interpreted as enhanced grain boundary migration and recovery. Below 1600 K, elasto-plastic self-consistent analysis suggests that below 3-4 GPa, deformation in olivine occurs with large contribution from the so-called 'a-slip' system [100](010). Above {approx}4 GPa, the contribution of the a-slip decreases relative to that of the 'c-slip' [001](010). This conclusion is further supported by texture refinements. Thus for polycrystalline olivine, the evolution in slip systems found by previous studies may be progressive, starting from as low as 3-4 GPa and up to 8 GPa. During such a gradual change, activation volumes measured on polycrystalline olivine cannot be linked to a particular slip system straightforwardly. The quest for 'the' activation volume of olivine at high pressure should cease at the expense of detailed work on the flow mechanisms implied. Such evolution in slip systems should also affect the interpretation of seismic anisotropy data in terms of upper mantle flow between 120 and 300 km depth.

  18. In-Situ Observation of Crystallization and Growth in High-Temperature Melts Using the Confocal Laser Microscope

    NASA Astrophysics Data System (ADS)

    Sohn, Il; Dippenaar, Rian

    2016-08-01

    This review discusses the innovative efforts initiated by Emi and co-workers for in-situ observation of phase transformations at high temperatures for materials. By using the high-temperature confocal laser-scanning microscope (CLSM), a robust database of the phase transformation behavior during heating and cooling of slags, fluxes, and steel can be developed. The rate of solidification and the progression of solid-state phase transformations can be readily investigated under a variety of atmospheric conditions and be correlated with theoretical predictions. The various research efforts following the work of Emi and co-workers have allowed a deeper fundamental understanding of the elusive solidification and phase transformation mechanisms in materials beyond the ambit of steels. This technique continues to evolve in terms of its methodology, application to other materials, and its contribution to technology.

  19. In-Situ Observation of Crystallization and Growth in High-Temperature Melts Using the Confocal Laser Microscope

    NASA Astrophysics Data System (ADS)

    Sohn, Il; Dippenaar, Rian

    2016-04-01

    This review discusses the innovative efforts initiated by Emi and co-workers for in-situ observation of phase transformations at high temperatures for materials. By using the high-temperature confocal laser-scanning microscope (CLSM), a robust database of the phase transformation behavior during heating and cooling of slags, fluxes, and steel can be developed. The rate of solidification and the progression of solid-state phase transformations can be readily investigated under a variety of atmospheric conditions and be correlated with theoretical predictions. The various research efforts following the work of Emi and co-workers have allowed a deeper fundamental understanding of the elusive solidification and phase transformation mechanisms in materials beyond the ambit of steels. This technique continues to evolve in terms of its methodology, application to other materials, and its contribution to technology.

  20. Lubricous Deposit Formed In Situ Between Wearing Surfaces at High Temperatures

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Many components of future aircraft will be constructed from novel high-temperature materials, such as superalloys and ceramic composites, to meet expected operating temperatures in excess of 300 C. There are no known liquid lubricants that can lubricate above 300 C without significant decomposition. Solid lubricants could be considered, but problems caused by the higher friction coefficients and wear rates of the solid lubricant film make this an undesirable approach. An alternative method of lubrication is currently being investigated: vapor phase lubrication. In vapor phase lubrication, an organic liquid (in our studies a thioether was used) is vaporized into a flowing air stream that is directed to sliding surfaces where lubrication is needed. The organic vapor reacts at the concentrated contact sliding area generating a lubricous deposit. This deposit has been characterized as a thin polymeric film that can provide effective lubrication at temperatures greater than 400 C. Initial tribological studies were conducted at the NASA Lewis Research Center and Cleveland State University with a high-temperature friction and wear tribometer. A cast iron rod was loaded (a 4-kg mass was used to generate a contact pressure of 1.2 MPa) against a reciprocating, cast iron plate at 500 C. This system was then lubricated with the vapor phase of thioether.

  1. In-situ Formation of Reinforcement Phases in Ultra High Temperature Ceramic Composites

    NASA Technical Reports Server (NTRS)

    Stackpoole, Margaret M (Inventor); Gasch, Matthew J (Inventor); Olson, Michael W (Inventor); Hamby, Ian W. (Inventor); Johnson, Sylvia M (Inventor)

    2013-01-01

    A tough ultra-high temperature ceramic (UHTC) composite comprises grains of UHTC matrix material, such as HfB.sub.2, ZrB.sub.2 or other metal boride, carbide, nitride, etc., surrounded by a uniform distribution of acicular high aspect ratio reinforcement ceramic rods or whiskers, such as of SiC, is formed from uniformly mixing a powder of the UHTC material and a pre-ceramic polymer selected to form the desired reinforcement species, then thermally consolidating the mixture by hot pressing. The acicular reinforcement rods may make up from 5 to 30 vol % of the resulting microstructure.

  2. In Situ Synthesis of Uranium Carbide and its High Temperature Cubic Phase

    SciTech Connect

    Reiche, Helmut Matthias; Vogel, Sven C.

    2015-03-25

    New in situ data for the U-C system are presented, with the goal of improving knowledge of the phase diagram to enable production of new ceramic fuels. The none quenchable, cubic, δ-phase, which in turn is fundamental to computational methods, was identified. Rich datasets of the formation synthesis of uranium carbide yield kinetics data which allow the benchmarking of modeling, thermodynamic parameters etc. The order-disorder transition (carbon sublattice melting) was observed due to equal sensitivity of neutrons to both elements. This dynamic has not been accurately described in some recent simulation-based publications.

  3. High-temperature dehydration of talc: a kinetics study using in situ X-ray powder diffraction

    NASA Astrophysics Data System (ADS)

    Wang, Duojun; Yi, Li; Huang, Bojin; Liu, Chuanjiang

    2015-06-01

    High-temperature in situ X-ray powder diffraction patterns were used to study the dehydration kinetics of natural talc with a size of 10-15 µm. The talc was annealed from 1073 to 1223 K, and the variations in the characteristic peaks corresponding to talc with the time were recorded to determine the reaction progress. The decomposition of talc occurred, and peaks corresponding to talc and peaks corresponding to enstatite and quartz were observed. The enstatite and talc exhibited a topotactic relationship. The dehydration kinetics of talc was studied as a function of temperature between 1073 and 1223 K. The kinetics data could be modeled using an Avrami equation that considers nucleation and growth processes ? where n varies from 0.4 to 0.8. The rate constant (k) equation for the natural talc is ? The reaction mechanism for the dehydration of talc is a heterogeneous nucleation and growth mechanism.

  4. In situ high temperature oxidation analysis of Zircaloy-4 using acoustic emission coupled with thermogravimetry

    NASA Astrophysics Data System (ADS)

    Omar, Al Haj; Véronique, Peres; Eric, Serris; François, Grosjean; Jean, Kittel; François, Ropital; Michel, Cournil

    2015-06-01

    Zircaloy-4 oxidation behavior at high temperature (900 °C), which can be reached in case of severe accidental situations in nuclear pressurised water reactor, was studied using acoustic emission analysis coupled with thermogravimetry. Two different atmospheres were used to study the oxidation of Zircaloy-4: (a) helium and pure oxygen, (b) helium and oxygen combined with slight addition of air. The experiments with 20% of oxygen confirm the dependence on oxygen anions diffusion in the oxide scale. Under a mixture of oxygen and air in helium, an acceleration of the corrosion was observed due to the detrimental effect of nitrogen. The kinetic rate increased significantly after a kinetic transition (breakaway). This acceleration was accompanied by an acoustic emission activity. Most of the acoustic emission bursts were recorded after the kinetic transition (post-transition) or during the cooling of the sample. The characteristic features of the acoustic emission signals appear to be correlated with the different populations of cracks and their occurrence in the ZrO2 layer or in the α-Zr(O) layer. Acoustic events were recorded during the isothermal dwell time at high temperature under air. They were associated with large cracks in the zirconia porous layer. Acoustic events were also recorded during cooling after oxidation tests both under air or oxygen. For the latter, cracks were observed in the oxygen enriched zirconium metal phase and not in the dense zirconia layer after 5 h of oxidation.

  5. In-situ X-ray structure measurements on aerodynamically levitated high temperature liquids

    SciTech Connect

    Weber, Richard; Benmore, Christopher; Mei Qiang; Wilding, Martin

    2009-01-29

    High energy, high flux X-ray sources enable new measurements of liquid and amorphous materials in extreme conditions. Aerodynamic levitation in combination with laser beam heating can be used to access high purity and non-equilibrium liquids at temperatures up to 3000 K. In this work, a small aerodynamic levitator was integrated with high energy beamline 11 ID-C at the Advanced Photon Source. Scattered X-rays were detected with a Mar345 image plate. The experiments investigated a series of binary in the CaO-Al{sub 2}O{sub 3}, MgO-SiO{sub 2}, SiO{sub 2}-Al{sub 2}O{sub 3} metal oxide compositions and pure SiO{sub 2}. The results show that the liquids exhibit large changes in structure when the predominant network former is diluted. Measurements on glasses with the same compositions as the liquids suggest that significant structural rearrangement consistent with a fragile-strong transition occurs in these reluctant glass forming liquids as they vitrify.

  6. Reactions Between Silicon and Graphite Substrates at High Temperature: In Situ Observations

    NASA Astrophysics Data System (ADS)

    White, Jesse F.; Ma, Luyao; Forwald, Karl; Sichen, Du

    2013-09-01

    Graphite as a refractory material has found wide application in many process steps to produce photovoltaic silicon. In the current study, the melting behavior of silicon in contact with different grades of graphite was investigated. The infiltration of silicon into graphite was found to be highly dependent on the internal structure of the graphite substrate. It was confirmed that the heating history of silicon in contact with a graphite substrate strongly influences the melting behavior, which is likely attributed to a gas-solid reaction that forms SiC at less than the liquidus temperature of silicon and alters the surface properties of the graphite. It was also observed that a concentration of CO greater than 5 pct in the inlet gas leads to SiC formation on the surface of the silicon and severely hinders melting.

  7. In situ temperature jump high-frequency dynamic nuclear polarization experiments: enhanced sensitivity in liquid-state NMR spectroscopy.

    PubMed

    Joo, Chan-Gyu; Hu, Kan-Nian; Bryant, Jeffrey A; Griffin, Robert G

    2006-07-26

    We describe an experiment, in situ temperature jump dynamic nuclear polarization (TJ-DNP), that is demonstrated to enhance sensitivity in liquid-state NMR experiments of low-gamma spins--13C, 15N, etc. The approach consists of polarizing a sample at low temperature using high-frequency (140 GHz) microwaves and a biradical polarizing agent and then melting it rapidly with a pulse of 10.6 microm infrared radiation, followed by observation of the NMR signal in the presence of decoupling. In the absence of polarization losses due to relaxation, the enhancement should be epsilon+ = epsilon(T(obs)/T(mu)(wave)), where epsilon+ is the observed enhancement, epsilon is the enhancement obtained at the temperature where the polarization process occurs, and T(mu)(wave) and T(obs) are the polarization and observation temperatures, respectively. In a single experimental cycle, we observe room-temperature enhancements, epsilon(dagger), of 13C signals in the range 120-400 when using a 140 GHz gyrotron microwave source, T(mu)(wave) = 90 K, and T(obs) = 300 K. In addition, we demonstrate that the experiment can be recycled to perform signal averaging that is customary in contemporary NMR spectroscopy. Presently, the experiment is applicable to samples that can be repeatedly frozen and thawed. TJ-DNP could also serve as the initial polarization step in experiments designed for rapid acquisition of multidimensional spectra. PMID:16848479

  8. Real-time in situ probing of high-temperature quantum dots solution synthesis.

    PubMed

    Abécassis, Benjamin; Bouet, Cécile; Garnero, Cyril; Constantin, Doru; Lequeux, Nicolas; Ithurria, Sandrine; Dubertret, Benoit; Pauw, Brian Richard; Pontoni, Diego

    2015-04-01

    Understanding the formation mechanism of colloidal nanocrystals is of paramount importance in order to design new nanostructures and synthesize them in a predictive fashion. However, reliable data on the pathways leading from molecular precursors to nanocrystals are not available yet. We used synchrotron-based time-resolved in situ small and wide-angle X-ray scattering to experimentally monitor the formation of CdSe quantum dots synthesized in solution through the heating up of precursors in octadecene at 240 °C. Our experiment yields a complete movie of the structure of the solution from the self-assembly of the precursors to the formation of the quantum dots. We show that the initial cadmium precursor lamellar structure melts into small micelles at 100 °C and that the first CdSe nuclei appear at 218.7 °C. The size distributions and concentration in nanocrystals are measured in a quantitative fashion as a function of time. We show that a short nucleation burst lasting 30 s is followed by a slow decrease of nanoparticle concentration. The rate-limiting process of the quantum dot formation is found to be the thermal activation of selenium. PMID:25815414

  9. In-Situ X-Ray Diffraction Observations of Low Temperature Ag-Nanoink Sintering and High Temperature Eutectic Reaction with Copper

    SciTech Connect

    Elmer, J. W.; Specht, Eliot D

    2012-01-01

    Nanoinks, which contain nm sized metallic particles suspended in an organic dispersant fluid, are finding numerous microelectronic applications. Nanoinks sinter at much lower temperatures than bulk metals due to their high surface area to volume ratio and small radius of curvature, which reduces their melting points significantly below their bulk values. The unusually low melting and sintering temperatures have unique potential for materials joining since their melting points increase dramatically after initial sintering. In this paper Ag nanoink is studied using in-situ synchrotron based x-ray diffraction to follow the kinetics of the initial sintering step by analysis of diffraction patterns, and to directly observe the high remelt temperature of sintered nanoinks. Ag nanoink is further explored as a possible eutectic bonding medium with copper by tracking phase transformations to high temperatures where melting occurs at the Ag-Cu eutectic temperature, demonstrating nanoinks as a viable eutectic bonding medium.

  10. In Situ Neutron and Synchrotron X-ray Diffraction Studies of Jarosite at High-Temperature High-Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Xu, H.; Zhao, Y.; Hickmott, D.; Zhang, J.; Vogel, S.; Daemen, L.; Hartl, M.

    2011-03-01

    Jarosite (KFe 3 (SO4)2 (OH)6) occurs in acid mine drainage and epithermal environments and hot springs associated with volcanic activity. Jarosite is also of industrial interest as an iron-impurity extractor from zinc sulfide ores. In 2004, jarosite was detected by the Mars Exploration Rover Mössbauer spectrometer, which has been interpreted as a strong evidence for the existence of water (and possibly life) on ancient Mars. This discovery has spurred considerable interests in stability and structural behavior of jarosite and related phases at various temperature, pressure, and aqueous conditions. In this work, we have investigated the crystal structure and phase stability of jarosite at temperatures up to 900 K and/or pressures up to 9 GPa using in situ neutron and synchrotron X-ray diffraction. To avoid the large incoherent scattering of neutrons by hydrogen, a deuterated sample was synthesized and characterized. Rietveld analysis of the obtained diffraction data allowed determination of unit-cell parameters, atomic positions and atomic displacement parameters as a function of temperature and pressure. In addition, the coefficients of thermal expansion, bulk moduli and pressure-temperature stability regions of jarosite were determined.

  11. In-situ, in air, high-temperature phase transformations in rare-earth niobates and titanium oxides (dysprosium and yttrium) using a thermal-image furnace

    NASA Astrophysics Data System (ADS)

    Siah, Lay Foong

    Thermal-image furnaces afford two major advantages over the conventional resistance heating systems for high-temperature studies of oxides in air, namely: (i) the highly localized heating allows temperatures in excess of 2500°C to be reached in air or in an oxidizing atmosphere, and (ii) no sample contamination from volatile furnace components since the sample is heated by absorption of a focused, high intensity light beam. In this work, we developed a compact furnace powered by four halogen infrared reflector lamps (150 W each), for in-situ high-temperature studies using synchrotron radiation. The primary objective was to evaluate the feasibility of the thermal-image technique for in-situ, in air, studies of high-temperature phase transformations in oxide ceramics. Specifically, the issues of temperature measurement and reliability of results obtained in comparison with published literature were addressed. The use of a co-existent "in-situ thermometer" was found to be a viable method to monitor the sample temperature in the image "hot-spot". Studies of YNbO4 and DyNbO4 revealed the existence of a new cubic phase at elevated temperatures beyond the commonly known ferroelastic monoclinic-to-paraelastic tetragonal transformations. A series of high-temperature powder patterns of the pure hexagonal phase of DY2TiO5 was also collected in-situ, in air.

  12. Development of a new micro-furnace for "in situ" high-temperature single crystal X-ray diffraction measurements

    NASA Astrophysics Data System (ADS)

    Alvaro, Matteo; Angel, Ross J.; Marciano, Claudio; Zaffiro, Gabriele; Scandolo, Lorenzo; Mazzucchelli, Mattia L.; Milani, Sula; Rustioni, Greta; Domeneghetti, Chiara M.; Nestola, Fabrizio

    2015-04-01

    Several experimental methods to reliably determine elastic properties of minerals at non-ambient conditions have been developed. In particular, different techniques for generating high-pressure and high-temperature have been successfully adopted for single-crystal and powder X-ray diffraction measurements. High temperature devices for "in-situ" measurements should provide the most controlled isothermal environment as possible across the entire sample. It is intuitive that in general, thermal gradients across the sample increase as the temperature increases. Even if the small isothermal volume required for single-crystal X-ray diffraction experiments makes such phenomena almost negligible, the design of a furnace should also aim to reduce thermal gradients by including a large thermal mass that encloses the sample. However this solution often leads to complex design that results in a restricted access to reciprocal space or attenuation of the incident or diffracted intensity (with consequent reduction of the accuracy and/or precision in lattice parameter determination). Here we present a newly-developed H-shaped Pt-Pt/Rh resistance microfurnace for in-situ high-temperature single-crystal X-ray diffraction measurements. The compact design of the furnace together with the long collimator-sample-detector distance allows us to perform measurements up to 2θ = 70° with no further restrictions on any other angular movement. The microfurnace is equipped with a water cooling system that allows a constant thermal gradient to be maintained that in turn guarantees thermal stability with oscillations smaller than 5°C in the whole range of operating T of room-T to 1200°C. The furnace has been built for use with a conventional 4-circle Eulerian geometry equipped with point detector and automated with the SINGLE software (Angel and Finger 2011) that allows the effects of crystal offsets and diffractometer aberrations to be eliminated from the refined peak positions by the 8

  13. In situ high pressure and temperature carbon-13 nmr for the study of carbonation reactions of carbon dioxide

    NASA Astrophysics Data System (ADS)

    Surface, James Andrew

    The aqueous reactions of carbon dioxide with various Mg-containing minerals [MgO, Mg(OH)2, and Mg2SiO4] at several different pressures (1-200 bar) and temperatures (25-150C) have been studied using a novel, elevated pressure and temperature 13C NMR probe. Critical observations about reaction rates, chemical exchange, and pH measurements throughout these reactions and the implications of the in situ measurements made during these reactions are discussed. A new method is used to elucidate pH under high pressure and temperature conditions which utilizes a calculation scheme wherein experimental data and a computational model are combined. Additionally, a 1D pH imaging method is employed to observe pH gradient effects across mineral samples during their reaction with CO2. Finally, other experimental details are discussed including ex situ analysis on carbonate products using pXRD, Raman, and MAS NMR. Detailed discussion outlines how to use 13C NMR to study CO2 mineralization reactions.

  14. In-situ X-ray diffraction analysis of zirconia layer formed on zirconium alloys oxidized at high temperature

    NASA Astrophysics Data System (ADS)

    Gosset, D.; Le Saux, M.

    2015-03-01

    In the case of a hypothetical loss of primary coolant accident (LOCA) in a light water reactor, the zirconium alloys fuel cladding would be oxidized in steam at high temperature, typically in the range 800-1200 °C. The monoclinic to tetragonal phase martensitic transition of zirconia occurs within this temperature range and complex phenomena possibly having an impact on the oxidation kinetics are then to be expected. In order to provide an accurate description of the structure and microstructure of the oxide layers, systematic X-ray diffraction analyses have been performed in-situ under oxidizing atmosphere at high temperature (between 800 and 1100 °C) on Zircaloy-4 and M5™ sheet samples. It was confirmed that the volume fraction of the tetragonal and monoclinic zirconia phases formed during oxide growth drastically depends on the oxidation temperature. For example, the few outer microns of the oxide are fully tetragonal above 1050 °C and contain only 20% of tetragonal phase at 800 °C. It was also shown that cooling after oxidation induces irreversible phase transitions within the oxide. As a consequence, both the structure and the microstructure of the growing oxide cannot be observed post-facto, neither at room temperature nor after reheating at the prior oxidation temperature. It has been deduced from microstructural analyses that the grain size of the tetragonal zirconia phase is nanometric, about 100 nm during oxidation at 1100 °C down to 20 nm after cooling down to room temperature. This small grain size allows the stabilization of the tetragonal phase. The lattice parameters of the monoclinic and tetragonal zirconia phases have been analyzed, during both high temperature oxidation and cooling. In both cases, it appears the 'a' and 'b' cell parameters of the monoclinic phase are strongly constrained by the tetragonal 'a' one. The structural characteristics of the oxide formed at high temperature on Zircaloy-4 and M5™ are quite similar. All those

  15. Development of self-powered wireless high temperature electrochemical sensor for in situ corrosion monitoring of coal-fired power plant.

    PubMed

    Aung, Naing Naing; Crowe, Edward; Liu, Xingbo

    2015-03-01

    Reliable wireless high temperature electrochemical sensor technology is needed to provide in situ corrosion information for optimal predictive maintenance to ensure a high level of operational effectiveness under the harsh conditions present in coal-fired power generation systems. This research highlights the effectiveness of our novel high temperature electrochemical sensor for in situ coal ash hot corrosion monitoring in combination with the application of wireless communication and an energy harvesting thermoelectric generator (TEG). This self-powered sensor demonstrates the successful wireless transmission of both corrosion potential and corrosion current signals to a simulated control room environment. PMID:25284768

  16. Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems

    SciTech Connect

    Pickrell, Gary; Scott, Brian

    2014-06-30

    This report covers the technical progress on the program “Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems”, funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Materials Science & Engineering and Electrical & Computer Engineering Departments at Virginia Tech, and summarizes technical progress from July 1st, 2005 –June 30th, 2014. The objective of this program was to develop novel fiber materials for high temperature gas sensors based on evanescent wave absorption in optical fibers. This project focused on two primary areas: the study of a sapphire photonic crystal fiber (SPCF) for operation at high temperature and long wavelengths, and a porous glass based fiber optic sensor for gas detection. The sapphire component of the project focused on the development of a sapphire photonic crystal fiber, modeling of the new structures, fabrication of the optimal structure, development of a long wavelength interrogation system, testing of the optical properties, and gas and temperature testing of the final sensor. The fabrication of the 6 rod SPCF gap bundle (diameter of 70μm) with a hollow core was successfully constructed with lead-in and lead-out 50μm diameter fiber along with transmission and gas detection testing. Testing of the sapphire photonic crystal fiber sensor capabilities with the developed long wavelength optical system showed the ability to detect CO2 at or below 1000ppm at temperatures up to 1000°C. Work on the porous glass sensor focused on the development of a porous clad solid core optical fiber, a hollow core waveguide, gas detection capabilities at room and high temperature, simultaneous gas species detection, suitable joining technologies for the lead-in and lead-out fibers and the porous sensor, sensor system sensitivity improvement, signal processing improvement, relationship between pore structure and fiber

  17. Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials.

    PubMed

    Weber, J K R; Tamalonis, A; Benmore, C J; Alderman, O L G; Sendelbach, S; Hebden, A; Williamson, M A

    2016-07-01

    An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions. PMID:27475566

  18. Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

    NASA Astrophysics Data System (ADS)

    Weber, J. K. R.; Tamalonis, A.; Benmore, C. J.; Alderman, O. L. G.; Sendelbach, S.; Hebden, A.; Williamson, M. A.

    2016-07-01

    An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

  19. In Situ Ptychography of Heterogeneous Catalysts using Hard X-Rays: High Resolution Imaging at Ambient Pressure and Elevated Temperature.

    PubMed

    Baier, Sina; Damsgaard, Christian D; Scholz, Maria; Benzi, Federico; Rochet, Amélie; Hoppe, Robert; Scherer, Torsten; Shi, Junjie; Wittstock, Arne; Weinhausen, Britta; Wagner, Jakob B; Schroer, Christian G; Grunwaldt, Jan-Dierk

    2016-02-01

    A new closed cell is presented for in situ X-ray ptychography which allows studies under gas flow and at elevated temperature. In order to gain complementary information by transmission and scanning electron microscopy, the cell makes use of a Protochips E-chipTM which contains a small, thin electron transparent window and allows heating. Two gold-based systems, 50 nm gold particles and nanoporous gold as a relevant catalyst sample, were used for studying the feasibility of the cell. Measurements showing a resolution around 40 nm have been achieved under a flow of synthetic air and during heating up to temperatures of 933 K. An elevated temperature exhibited little influence on image quality and resolution. With this study, the potential of in situ hard X-ray ptychography for investigating annealing processes of real catalyst samples is demonstrated. Furthermore, the possibility to use the same sample holder for ex situ electron microscopy before and after the in situ study underlines the unique possibilities available with this combination of electron microscopy and X-ray microscopy on the same sample. PMID:26914998

  20. Beamline Electrostatic Levitator (BESL) for in-situ High Energy K-Ray Diffraction Studies of Levitated Solids and Liquids at High Temperature

    NASA Technical Reports Server (NTRS)

    Gangopadhyay, A. K.; Lee, G. W.; Kelton, K. F.; Rogers, J. R.; Goldman, A. I.; Robinson, D. S.; Rathz, T. J.; Hyers, R. W.

    2005-01-01

    Determinations of the phase formation sequence, the crystal structures and the thermodynamic properties of materials at high temperatures are difficult because of contamination from the sample container and environment. Containerless processing techniques, such as electrostatic (ESL), electromagnetic (EML), aerodynamic, and acoustic levitation, are most suitable these studies. An adaptation of ESL for in-situ structural studies of a wide range of materials, including metals, semiconductors, insulators using high energy (125 keV) synchrotron x-rays is described here. This beamline ESL (BESL) allows the in-situ determination of the atomic structures of equilibrium solid and liquid phases, including undercooled liquids, as well as real-time studies of solid-solid and liquid-solid phase transformations. The use of image plate (MAR345) or GE-Angio detectors enables fast (30 ms - 1s) acquisition of complete diffraction patterns over a wide q-range (4 - 140/mm). The wide temperature range (300 - 2500 K), containerless processing under high vacuum (10(exp -7) - 10(exp -8) torr), and fast data acquisition, make BESL particularly suitable for phase diagram studies of high temperature materials. An additional, critically important, feature of BESL is the ability to also make simultaneous measurement of a host of thermo-physical properties, including the specific heat, enthalpy of transformation, solidus and liquidus temperatures, density, viscosity, and surface tension; all on the same sample and simultaneous with the structural measurements.

  1. Generation of methane in the Earth's mantle: In situ high pressure–temperature measurements of carbonate reduction

    PubMed Central

    Scott, Henry P.; Hemley, Russell J.; Mao, Ho-kwang; Herschbach, Dudley R.; Fried, Laurence E.; Howard, W. Michael; Bastea, Sorin

    2004-01-01

    We present in situ observations of hydrocarbon formation via carbonate reduction at upper mantle pressures and temperatures. Methane was formed from FeO, CaCO3-calcite, and water at pressures between 5 and 11 GPa and temperatures ranging from 500°C to 1,500°C. The results are shown to be consistent with multiphase thermodynamic calculations based on the statistical mechanics of soft particle mixtures. The study demonstrates the existence of abiogenic pathways for the formation of hydrocarbons in the Earth's interior and suggests that the hydrocarbon budget of the bulk Earth may be larger than conventionally assumed. PMID:15381767

  2. In-Situ Study of Gaseous Reduction of Magnetite Doped with Alumina Using High-Temperature XRD Analysis

    NASA Astrophysics Data System (ADS)

    Kapelyushin, Yury; Sasaki, Yasushi; Zhang, Jianqiang; Jeong, Sunkwang; Ostrovski, Oleg

    2015-12-01

    The reduction of magnetite of technical grade and magnetite doped with 3 mass pct Al2O3 was studied in situ using high-temperature XRD (HT-XRD) analysis. Magnetite was reduced by CO-CO2 gas (80 vol pct CO) at 1023 K (750 °C). Reduction of magnetite doped with alumina occurred from the Fe3O4-FeAl2O4 solid solution which has a miscibility gap with critical temperature of 1133 K (860 °C). The degree of reduction of magnetite was derived using Rietveld refinement of the HT-XRD spectra; the compositions of the Fe3O4-FeAl2O4 solid solution and the concentrations of carbon in γ-iron were determined from the lattice constants of the solutions. The reduction of magnetite progressed topochemically with the formation of a dense iron shell. The reduction of alumina-containing magnetite started along certain lattice planes with the formation of a network-like structure. Reduction of alumina-containing magnetite was faster than that of un-doped magnetite; this difference was attributed to the formation of the network-like structure. Hercynite content in the Fe3O4-FeAl2O4 solid solution in the process of reduction of magnetite doped with 3 mass pct Al2O3 increased from 5.11 to 20 mass pct, which is close to the miscibility gap at 1023 K (750 °C). The concentration of carbon in γ-Fe (0.76 mass pct) formed in the reduced sample of magnetite doped with 3 mass pct Al2O3 was close to the equilibrium value with 80 vol pct CO to 20 vol pct CO2 gas used in the HT-XRD experiments.

  3. Development of Nano-crystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases

    SciTech Connect

    Xiao, Hai; Dong, Junhang; Lin, Jerry; Romero, Van

    2012-03-01

    This is a final technical report for the first project year from July 1, 2005 to Jan 31, 2012 for DoE/NETL funded project DE-FC26-05NT42439: Development of Nanocrystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases. This report summarizes the technical progresses and achievements towards the development of novel nanocrystalline doped ceramic material-enabled optical fiber sensors for in situ and real time monitoring the gas composition of flue or hot gas streams involved in fossil-fuel based power generation and hydrogen production.

  4. In situ high-temperature scanning tunneling microscopy studies of early stage growth kinetics during titanium nitride epitaxy

    NASA Astrophysics Data System (ADS)

    Kodambaka, Suneel Kumar

    NaCl-structure TiN is widely used as a hard wear-resistant coating on cutting tools, as a diffusion-barrier layer in microelectronic devices, as a corrosion-resistant coating on mechanical components, and as an abrasion-resistant layer on optics and architectural glass. Even though its diffusion barrier and elastic properties are known to be anisotropic, and hence depend upon grain orientation, little is known regarding the mechanisms and reaction paths leading to the development of preferred orientation in polycrystalline TiN layers deposited by reactive evaporation and sputter deposition. Efforts to model polycrystalline growth as a function of deposition conditions is a complex problem. As a minimum set, one requires adatom transport parameters---activation barriers for surface diffusion step edge attachment/detachment, the adatom formation energy, the step edge Ehrlich barrier, and the step formation energy---all as a function of orientation. Unfortunately, very little data, either experimental or theoretical, is available concerning these parameters for TiN. During the course of my research, I have developed methods to grow atomically-smooth TiN(001) and (111) single-crystal layers with simple well-defined single-atom-high 2D island configurations on large atomically-smooth terraces. I used in situ scanning tunneling microscopy to study time- and temperature-dependent 2D island coarsening/decay kinetics, obtain 2D equilibrium island shapes, and follow temporal fluctuations of island shapes on both TiN(001) and (111) surfaces. I have developed a combination of experimental and theoretical techniques to analyze the surface dynamics measurements and determined adatom surface transport parameters, step energies, step stiffnesses, and kink formation energies on TiN(001) and TiN(111) surfaces.

  5. [In situ experimental study of phase transition of calcite by Raman spectroscopy at high temperature and high pressure].

    PubMed

    Liu, Chuan-jiang; Zheng, Hai-fei

    2012-02-01

    The phase transitions of calcite at high temperature and high pressure were investigated by using hydrothermal diamond anvil cell combined with Raman spectroscopy. The result showed that the Raman peak of 155 cm(-1) disappeared, the peak of 1 087 cm(-1) splited into 1083 and 1 090 cm(-1) peaks and the peak of 282 cm(-1) abruptly reduced to 231 cm(-1) at ambient temperature when the system pressure increased to 1 666 and 2 127 MPa respectively, which proved that calcite transformed to calcite-II and calcite-III. In the heating process at the initial pressure of 2 761 MPa and below 171 degrees C, there was no change in Raman characteristic peaks of calcite-III. As the temperature increased to 171 degrees C, the color of calcite crystal became opaque completely and the symmetric stretching vibration peak of 1 087 cm(-1), in-plane bending vibration peak of 713 cm(-1) and lattice vibration peaks of 155 and 282 cm(-1) began to mutate, showing that the calcite-III transformed to a new phase of calcium carbonate at the moment. When the temperature dropped to room temperature, this new phase remained stable all along. It also indicated that the process of phase transformation from calcite to the new phase of calcium carbonate was irreversible. The equation of phase transition between calcite-III and new phase of calcium carbonate can be determined by P(MPa) = 9.09T x (degrees C) +1 880. The slopes of the Raman peak (v1 087) of symmetrical stretching vibration depending on pressure and temperature are dv/dP = 5.1 (cm(-1) x GPa(-1)) and dv/dT = -0.055 3(cm(-1) x degrees C(-1)), respectively. PMID:22512172

  6. Nanoparticle metamorphosis: an in situ high-temperature transmission electron microscopy study of the structural evolution of heterogeneous Au:Fe2O3 nanoparticles.

    PubMed

    Baumgardner, William J; Yu, Yingchao; Hovden, Robert; Honrao, Shreyas; Hennig, Richard G; Abruña, Héctor D; Muller, David; Hanrath, Tobias

    2014-05-27

    High-temperature in situ electron microscopy and X-ray diffraction have revealed that Au and Fe2O3 particles fuse in a fluid fashion at temperatures far below their size-reduced melting points. With increasing temperature, the fused particles undergo a sequence of complex structural transformations from surface alloy to phase segregated and ultimately core-shell structures. The combination of in situ electron microscopy and spectroscopy provides insights into fundamental thermodynamic and kinetic aspects governing the formation of heterogeneous nanostructures. The observed structural transformations present an interesting analogy to thin film growth on the curved surface of a nanoparticle. Using single-particle observations, we constructed a phase diagram illustrating the complex relationships among composition, morphology, temperature, and particle size. PMID:24758698

  7. In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

    NASA Astrophysics Data System (ADS)

    Gussev, M. N.; Byun, T. S.; Yamamoto, Y.; Maloy, S. A.; Terrani, K. A.

    2015-11-01

    One of the most essential properties of accident tolerant fuel (ATF) for maintaining structural integrity during a loss-of-coolant accident (LOCA) is high resistance of the cladding to plastic deformation and burst failure, since the deformation and burst behavior governs the cooling efficiency of flow channels and the process of fission product release. To simulate and evaluate the deformation and burst process of thin-walled cladding, an in-situ testing and evaluation method has been developed on the basis of visual imaging and image analysis techniques. The method uses a specialized optics system consisting of a high-resolution video camera, a light filtering unit, and monochromatic light sources. The in-situ testing is performed using a 50 mm long pressurized thin-walled tubular specimen set in a programmable furnace. As the first application, ten (10) candidate cladding materials for ATF, i.e., five FeCrAl alloys and five nanostructured steels, were tested using the newly developed method, and the time-dependent images were analyzed to produce detailed deformation and burst data such as true hoop stress, strain (creep) rate, and failure stress. Relatively soft FeCrAl alloys deformed and burst below 800 °C, while negligible strain rates were measured for higher strength alloys.

  8. In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

    DOE PAGESBeta

    Byun, Thak Sang; Yamamoto, Yukinori; Maloy, Stuart A.; Gussev, M. N.; Terrani, K. A.

    2015-08-25

    Here, one of the most essential properties of accident tolerant fuel (ATF) for maintaining structural integrity during a loss-of-coolant accident (LOCA) is high resistance of the cladding to plastic deformation and burst failure, since the deformation and burst behavior governs the cooling efficiency of flow channels and the process of fission product release. To simulate and evaluate the deformation and burst process of thin-walled cladding, an in-situ testing and evaluation method has been developed on the basis of visual imaging and image analysis techniques. The method uses a specialized optics system consisting of a high-resolution video camera, a light filteringmore » unit, and monochromatic light sources. The in-situ testing is performed using a 50 mm long pressurized thin-walled tubular specimen set in a programmable furnace. As the first application, ten (10) candidate cladding materials for ATF, i.e., five FeCrAl alloys and five nanostructured steels, were tested using the newly developed method, and the time-dependent images were analyzed to produce detailed deformation and burst data such as true hoop stress, strain (creep) rate, and failure stress. Relatively soft FeCrAl alloys deformed and burst below 800 °C, while negligible strain rates were measured for higher strength alloys.« less

  9. In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

    SciTech Connect

    Byun, Thak Sang; Yamamoto, Yukinori; Maloy, Stuart A.; Gussev, M. N.; Terrani, K. A.

    2015-08-25

    Here, one of the most essential properties of accident tolerant fuel (ATF) for maintaining structural integrity during a loss-of-coolant accident (LOCA) is high resistance of the cladding to plastic deformation and burst failure, since the deformation and burst behavior governs the cooling efficiency of flow channels and the process of fission product release. To simulate and evaluate the deformation and burst process of thin-walled cladding, an in-situ testing and evaluation method has been developed on the basis of visual imaging and image analysis techniques. The method uses a specialized optics system consisting of a high-resolution video camera, a light filtering unit, and monochromatic light sources. The in-situ testing is performed using a 50 mm long pressurized thin-walled tubular specimen set in a programmable furnace. As the first application, ten (10) candidate cladding materials for ATF, i.e., five FeCrAl alloys and five nanostructured steels, were tested using the newly developed method, and the time-dependent images were analyzed to produce detailed deformation and burst data such as true hoop stress, strain (creep) rate, and failure stress. Relatively soft FeCrAl alloys deformed and burst below 800 °C, while negligible strain rates were measured for higher strength alloys.

  10. In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

    SciTech Connect

    Gussev, Maxim N.; Byun, Thak Sang; Yamamoto, Yukinori; Maloy, Stuart A.; Terrani, Kurt A.

    2015-11-01

    The high resistance of cladding to plastic deformation and burst failure is one of the most essential properties of accident tolerant fuel (ATF) for maintaining structural integrity during a loss-of-coolant accident (LOCA) since the deformation and burst behavior governs the cooling efficiency of flow channels and process of fission product release. To simulate and evaluate such deformation and burst process of thin-walled cladding, an in-situ testing and evaluation method has been developed on the basis of visual imaging and image analysis techniques. The method uses a specialized optics system consisted of a high-resolution video camera, light filtering unit, and monochromatic light sources, and the in-situ testing is performed using a 50 mm long pressurized thin-walled tubular specimen set in a programmable furnace. In this study eleven (11) candidate cladding materials for ATF, i.e., 6 FeCrAl alloys and 5 nanostructured steels, were tested using the newly developed method, and the time-dependent images were analyzed to produce detailed deformation and burst data such as true hoop stress, strain (creep) rate, and failure stress. Relatively soft FeCrAl alloys deformed and burst below 800°C while negligible strain rates were measured for higher strength alloys and/or for relatively thick wall specimens.

  11. An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments.

    PubMed

    Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

    2015-01-01

    Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively. PMID:26334279

  12. Phase transition in Ba{sub 2}In{sub 2}O{sub 5} studied by in situ high temperature X-ray diffraction using synchrotron radiation

    SciTech Connect

    Rey, J. F. Q.; Ferreira, F. F.; Muccillo, E. N. S.

    2009-01-29

    The order-disorder phase transition in Ba{sub 2}In{sub 2}O{sub 5} high-temperature ionic conductor was systematically studied by in situ high-temperature X-ray diffraction using synchrotron radiation and electrical conductivity. Pure barium indate was prepared by solid state reactions at 1300 deg. C. The room-temperature structural characterization showed a high degree of phase homogeneity in the prepared material. The reduction of the order-disorder phase transition temperature was verified by electrical conductivity and high-temperature X-ray diffraction. The observed features were explained based on Fourier-transform infrared spectroscopy results that revealed the presence of hydroxyl species in the crystal lattice. The increase of the intensity of few diffraction peaks near the phase transition temperature suggests the formation of a superstructure before the orthorhombic-to-tetragonal phase transition.

  13. An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments

    PubMed Central

    Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

    2015-01-01

    Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively. PMID:26334279

  14. InAlN high electron mobility transistor Ti/Al/Ni/Au Ohmic contact optimisation assisted by in-situ high temperature transmission electron microscopy

    SciTech Connect

    Smith, M. D.; Parbrook, P. J.; O'Mahony, D.; Conroy, M.; Schmidt, M.

    2015-09-14

    This paper correlates the micro-structural and electrical characteristics associated with annealing of metallic multi-layers typically used in the formation of Ohmic contacts to InAlN high electron mobility transistors. The multi-layers comprised Ti/Al/Ni/Au and were annealed via rapid thermal processing at temperatures up to 925 °C with electrical current-voltage analysis establishing the onset of Ohmic (linear IV) behaviour at 750–800 °C. In-situ temperature dependent transmission electron microscopy established that metallic diffusion and inter-mixing were initiated near a temperature of 500 °C. Around 800 °C, inter-diffusion of the metal and semiconductor (nitride) was observed, correlating with the onset of Ohmic electrical behaviour. The sheet resistance associated with the InAlN/AlN/GaN interface is highly sensitive to the anneal temperature, with the range depending on the Ti layer thickness. The relationship between contact resistivity and measurement temperature follow that predicted by thermionic field emission for contacts annealed below 850 °C, but deviated above this due to excessive metal-semiconductor inter-diffusion.

  15. In situ X-ray observations of the melting relations in the Fe-S-H system under high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Shibazaki, Y.; Stagno, V.; Higo, Y.; Fei, Y.

    2013-12-01

    Sulfur and hydrogen are two of the most plausible light elements in the planetary cores. Particularly the cores of icy satellites, such as Ganymede, are considered to contain a significant amount of those elements based on studies of meteorites. Therefore, it is essential to investigate the properties of iron alloyed with those light elements at high pressure and high temperature, in order to shed light on the composition and structure of the cores. To date, the Fe-FeS system has been extensively investigated at high pressure and temperature. Hydrogen is known to dissolve in interstitial sites of Fe and FeS lattices and strongly depresses the melting temperatures. However, it is still not clear how hydrogen affects the eutectic point (temperature and composition) of the Fe-FeS system. In order to understand the melting relations in the Fe-S-H system, we have performed in situ X-ray diffraction experiments at high pressure and high temperature. The experiments were carried out using the multi-anvil apparatus at the BL04B1 beamline of SPring-8, Japan, up to 10 GPa and 1700 K. Fe-FeS powder mixtures (15.5 wt% S and 30 wt %S) were packed into a NaCl capsule along with LiAlH4. Hydrogen was supplied to the Fe-FeS sample by a thermal decomposition of LiAlH4. The Fe-FeS sample was separated from LiAlH4 using a thin MgO disk to avoid the direct chemical reaction between the sample and LiAlH4. The NaCl capsule is able to seal hydrogen effectively at high pressure and high temperature. The diffraction patterns were collected for a period of 300 s at a temperature interval of 50-100 K. The collected diffraction data show that FeHx and FeSHx were synthesized at high temperature and then the sample was totally molten via a partial melting with increasing temperature. Since the atomic volumes of Fe and FeS expand due to the hydrogen dissolution (hydrogenation), the hydrogen concentrations in FeHx and FeSHx were estimated by comparing the volumes of between Fe and FeHx or between

  16. High pressure and high temperature in situ X-ray diffraction studies in the Paris-Edinburgh cell using a laboratory X-ray source†

    NASA Astrophysics Data System (ADS)

    Toulemonde, Pierre; Goujon, Céline; Laversenne, Laetitia; Bordet, Pierre; Bruyère, Rémy; Legendre, Murielle; Leynaud, Olivier; Prat, Alain; Mezouar, Mohamed

    2014-04-01

    We have developed a new laboratory experimental set-up to study in situ the pressure-temperature phase diagram of a given pure element or compound, its associated phase transitions, or the chemical reactions involved at high pressure and high temperature (HP-HT) between different solids and liquids. This new tool allows laboratory studies before conducting further detailed experiments using more brilliant synchrotron X-ray sources or before kinetic studies. This device uses the diffraction of X-rays produced by a quasi-monochromatic micro-beam source operating at the silver radiation (λ(Ag)Kα 1, 2≈0.56 Å). The experimental set-up is based on a VX Paris-Edinburgh cell equipped with tungsten carbide or sintered diamond anvils and uses standard B-epoxy 5 or 7 mm gaskets. The diffracted signal coming from the compressed (and heated) sample is collected on an image plate. The pressure and temperature calibrations were performed by diffraction, using conventional calibrants (BN, NaCl and MgO) for determination of the pressure, and by crossing isochores of BN, NaCl, Cu or Au for the determination of the temperature. The first examples of studies performed with this new laboratory set-up are presented in the article: determination of the melting point of germanium and magnesium under HP-HT, synthesis of MgB2 or C-diamond and partial study of the P, T phase diagram of MgH2.

  17. A high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure measurement.

    PubMed

    Murata, Naoyoshi; Kobayashi, Makoto; Okada, Yukari; Suzuki, Takuya; Nitani, Hiroaki; Niwa, Yasuhiro; Abe, Hitoshi; Wada, Takahiro; Mukai, Shingo; Uehara, Hiromitsu; Ariga, Hiroko; Takakusagi, Satoru; Asakura, Kiyotaka

    2015-03-01

    We present the design and performance of a high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure (XAFS) spectra. The cell has a large fluorescence XAFS window (116 mm(ϕ)) near the sample in the cell, realizing a large half-cone angle of 56°. We use a small heater (25 × 35 mm(2)) to heat the sample locally to 873 K. We measured a Pt-SnO2 thin layer on a Si substrate at reaction conditions having a high activity. In situ measurement enables the analysis of the difference XAFS spectra between before and during the reaction to reveal the structure change during the operation. PMID:25832248

  18. Design and application of a high-temperature microfurnace for an in situ X-ray diffraction study of phase transformation.

    PubMed

    Eu, W S; Cheung, W H; Valix, M

    2009-11-01

    Thermal treatment of mineral ores such as ilmenite can initiate phase transformations that could affect their activation or deactivation, subsequently influencing their ability to dissolve in a leaching agent. Most laboratory-based X-ray diffraction (XRD) studies were carried out ex situ in which realistic diffraction patterns could not be obtained simultaneously with occurring reactions and were time-consuming. The availability of synchrotron-radiation-based XRD not only allows in situ analysis, but significantly shortens the data recording time. The present study details the design of a robust high-temperature microfurnace which allows thermal processing of mineral ore samples and the simultaneous collection of high-resolution synchrotron XRD data. In addition, the application of the manufactured microfurnace for in situ study of phase transformations of ilmenite ore under reducing conditions is demonstrated. PMID:19844022

  19. High-Temperature Tensile and Tribological Behavior of Hybrid (ZrB2+Al3Zr)/AA5052 In Situ Composite

    NASA Astrophysics Data System (ADS)

    Gautam, G.; Kumar, N.; Mohan, A.; Gautam, R. K.; Mohan, S.

    2016-07-01

    During service life, components such as piston, cylinder blocks, brakes, and discs/drums, have to work under high-temperature conditions. In order to have appropriate material for such applications high-temperature studies are important. Hybrid (ZrB2+Al3Zr)/AA5052 in situ composite has been investigated from ambient to 523 K (250 °C) at an interval of 50 deg. (ZrB2+Al3Zr)/AA5052 in situ composite has been fabricated by the direct melt reaction of AA5052 alloy with zirconium and boron salts. Microstructure studies show refinement in the grain size of base alloy on in situ formation of reinforcement particles. Al3Zr particles are observed in rectangular and polyhedron shapes. It is observed from the tensile studies that ultimate tensile strength, yield strength, and percentage elongation decrease with increase in test temperature. Similar kind of behavior is also observed for flow curve properties. The tensile results have also been correlated with fractography. Wear and friction results indicate that the wear rate increases with increase in normal load, whereas coefficient of friction shows decreasing trend. With increasing test temperature, wear rate exhibits a typical phenomenon. After an initial increase, wear rate follows a decreasing trend up to 423 K (150 °C), and finally a rapid increase is observed, whereas coefficient of friction increases continuously with increase in test temperature. The mechanisms responsible for the variation of wear and friction with different temperatures have been discussed in detail with the help of worn surfaces studies under scanning electron microscope (SEM) & 3D-profilometer and debris analysis by XRD.

  20. High-Temperature Tensile and Tribological Behavior of Hybrid (ZrB2+Al3Zr)/AA5052 In Situ Composite

    NASA Astrophysics Data System (ADS)

    Gautam, G.; Kumar, N.; Mohan, A.; Gautam, R. K.; Mohan, S.

    2016-09-01

    During service life, components such as piston, cylinder blocks, brakes, and discs/drums, have to work under high-temperature conditions. In order to have appropriate material for such applications high-temperature studies are important. Hybrid (ZrB2+Al3Zr)/AA5052 in situ composite has been investigated from ambient to 523 K (250 °C) at an interval of 50 deg. (ZrB2+Al3Zr)/AA5052 in situ composite has been fabricated by the direct melt reaction of AA5052 alloy with zirconium and boron salts. Microstructure studies show refinement in the grain size of base alloy on in situ formation of reinforcement particles. Al3Zr particles are observed in rectangular and polyhedron shapes. It is observed from the tensile studies that ultimate tensile strength, yield strength, and percentage elongation decrease with increase in test temperature. Similar kind of behavior is also observed for flow curve properties. The tensile results have also been correlated with fractography. Wear and friction results indicate that the wear rate increases with increase in normal load, whereas coefficient of friction shows decreasing trend. With increasing test temperature, wear rate exhibits a typical phenomenon. After an initial increase, wear rate follows a decreasing trend up to 423 K (150 °C), and finally a rapid increase is observed, whereas coefficient of friction increases continuously with increase in test temperature. The mechanisms responsible for the variation of wear and friction with different temperatures have been discussed in detail with the help of worn surfaces studies under scanning electron microscope (SEM) & 3D-profilometer and debris analysis by XRD.

  1. X ray attenuation measurements for high-temperature materials characterization and in-situ monitoring of damage accumulation. Ph.D. Thesis - Cleveland State Univ., 1991

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.

    1992-01-01

    The scope of this dissertation is to develop and apply x ray attenuation measurement systems that are capable of: (1) characterizing density variations in high-temperature materials, e.g., monolithic ceramics, ceramic and intermetallic matrix composites, and (2) noninvasively monitoring damage accumulation and failure sequences in ceramic matrix composites under room temperature tensile testing. This dissertation results in the development of: (1) a point scan digital radiography system, and (2) an in-situ x ray material testing system. Radiographic evaluation before, during, and after loading shows the effect of preexisting volume flaws on the fracture behavior of composites. Results show that x ray film radiography can monitor damage accumulation during tensile loading. Matrix cracking, fiber matrix debonding, fiber bridging, and fiber pullout are imaged throughout the tensile loading of the specimens. Further in-situ radiography is found to be a practical technique for estimating interfacial shear strength between the silicon carbide fibers and the reaction bonded silicon nitride matrix. It is concluded that pretest, in-situ, and post test x ray imaging can provide for greater understanding of ceramic matrix composite mechanical behavior.

  2. 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.

    NASA Astrophysics Data System (ADS)

    Liermann, H.; Merkel, S.; Miyagi, L.; Wenk, H.; Shen, G.; Cynn, H.; Evans, W. J.

    2007-12-01

    Radial diffraction in the diamond anvil cell (DAC) has long been used to determine the stress state of materials under non-hydrostatic compression. This technique is also a major tool to investigate textures and infer deformation mechanisms in high pressure minerals. However, most of these experiments have been conducted at ambient temperatures and therefore the results of these measurements may be difficult to extrapolate to the deep Earth. Here, we present a new experimental design that was tested at HPCAT sector 16 BMD of the Advanced Photon Source. This method allows in situ measurement of stresses and textures in the DAC at simultaneously high- pressures and -temperatures. Details of this new technique that uses radial diffraction geometry are discussed, including the uses of amorphous boron gaskets, external heating using graphite heater, and membrane pressure control. Current coverage in pressure and temperature (~30 GPa and 1100 oC). The use of the method will be demonstrated with in situ texture measurements on the high-pressure phases of iron. In the experiment, we were able to observe strong textures in bcc-Fe, track the evolution of the texture with increasing temperature and during the bcc to fcc phase transition. Finally, we observed plastic deformation in the fcc phase between 5 and 15 GPa at 850 oC till the nucleation of hcp-Fe.

  3. In situ high-temperature X-ray diffraction and spectroscopic study of fibroferrite, FeOH(SO4)·5H2O

    NASA Astrophysics Data System (ADS)

    Ventruti, Gennaro; Ventura, Giancarlo Della; Corriero, Nicola; Malferrari, Daniele; Gualtieri, Alessandro F.; Susta, Umberto; Lacalamita, Maria; Schingaro, Emanuela

    2016-05-01

    The thermal dehydration process of fibroferrite, FeOH(SO4)·5H2O, a secondary iron-bearing hydrous sulfate, was investigated by in situ high-temperature synchrotron X-ray powder diffraction (HT-XRPD), in situ high-temperature Fourier transform infrared spectroscopy (HT-FTIR) and thermal analysis (TGA-DTA) combined with evolved gas mass spectrometry. The data analysis allowed the determination of the stability fields and the reaction paths for this mineral as well as characterization of its high-temperature products. Five main endothermic peaks are observed in the DTA curve collected from room T up to 800 °C. Mass spectrometry of gases evolved during thermogravimetric analysis confirms that the first four mass loss steps are due to water emission, while the fifth is due to a dehydroxylation process; the final step is due to the decomposition of the remaining sulfate ion. The temperature behavior of the different phases occurring during the heating process was analyzed, and the induced structural changes are discussed. In particular, the crystal structure of a new phase, FeOH(SO4)·4H2O, appearing at about 80 °C due to release of one interstitial H2O molecule, was solved by ab initio real-space and reciprocal-space methods. This study contributes to further understanding of the dehydration mechanism and thermal stability of secondary sulfate minerals.

  4. Sound velocities measurement on MgSiO3 akimotoite at high pressures and high temperatures with simultaneous in situ X-ray diffraction and ultrasonic study

    NASA Astrophysics Data System (ADS)

    Zhou, Chunyin; Gréaux, Steeve; Nishiyama, Norimasa; Irifune, Tetsuo; Higo, Yuji

    2014-03-01

    Elastic wave velocities of MgSiO3 akimotoite polycrystalline samples have been measured at pressures up to 25.7 GPa and temperatures to 1500 K by a combination of in situ X-ray diffraction and ultrasonic interferometry techniques in a large volume Kawai-type multianvil apparatus (KMA). The elastic moduli of akimotoite and their pressure and temperature dependences are determined by a 2D linear fitting analysis of the present data, yielding: KS = 219.4(7) GPa, ∂KS/∂P = 4.62(3), ∂KS/∂T = -0.0228(4) GPa/K, G0 = 132.1(7) GPa, ∂G/∂P = 1.63(4), ∂G/∂T = -0.0225(4) GPa/K. The bulk and shear moduli at ambient conditions are generally consistent with the result of a previous Brillouin study. However, significant nonlinear behaviors of the elastic moduli were observed at higher temperatures, indicating that the velocities derived from the linear fitting analysis are overestimated for the actual mantle conditions. Using the present new experimental data, we compared the elastic velocities of various high-pressure forms of MgSiO3 under the mantle conditions. The results demonstrate a large velocity difference between akimotoite and perovskite, which may be relevant to the complex seismic structures near the bottom of the mantle transition zone.

  5. An In Situ High Temperature Investigation of Cation Environments in Aluminate and Silicate Glasses and Liquids at the LUCIA Beamline

    SciTech Connect

    Neuville, Daniel R.; Roux, Jacques; Cormier, Laurent; Ligny, Dominique de; Flank, Anne-Marie; Lagarde, Pierre; Henderson, Grant S.

    2007-02-02

    The structure of crystals and melts were obtained at high temperature using X-ray absorption at the Ca K-edge on CaMgSi2O6 (diopside), CaAl2Si2O8 (anorthite), Ca3Al2O6 (C3A) and CaAl2O4 (CA) compositions. Important changes are observed above the liquidus temperature particularly for the C3A composition where all oscillations in the XANES spectra disappear. Important changes in the Ca K-edge XANES are also visible in the pre-edge region, with increasing temperature, for crystalline CaMgSi2O6.

  6. In situ high temperature magnetic force microscope analysis of thermal stability in the granular-type FePt-MgO double-layered perpendicular recording media

    NASA Astrophysics Data System (ADS)

    Singh, Amarendra K.; Zhang, Zhengang; Yin, Jinhua; Suzuki, Takao

    2005-05-01

    Thermal stability of written bits with different linear densities on granular-type FePt-MgO double-layered perpendicular magnetic recording media has been investigated by magnetic force microscope (MFM) technique, equipped with an in situ heating system up to 200°C. Within the measurement time scale (˜6h), there is no observable degradation in 50- and 100-kfci bits even at 200°C indicating good thermal stability of FePt media, while in 10-kfci bits some reversed domains are found at high temperatures in the center region of the bits due to the presence of strong demagnetizing field. The average MFM signal extracted from MFM images at high temperature is interpreted based on the temperature-dependent magnetic anisotropy (Ku) behavior of the FePt media.

  7. High-temperature "spectrochronopotentiometry": correlating electrochemical performance with in situ Raman spectroscopy in solid oxide fuel cells.

    PubMed

    Kirtley, John D; Halat, David M; McIntyre, Melissa D; Eigenbrodt, Bryan C; Walker, Robert A

    2012-11-20

    Carbon formation or "coking" on solid oxide fuel cell (SOFC) anodes adversely affects performance by blocking catalytic sites and reducing electrochemical activity. Quantifying these effects, however, often requires correlating changes in SOFC electrochemical efficiency measured during operation with results from ex situ measurements performed after the SOFC has been cooled and disassembled. Experiments presented in this work couple vibrational Raman spectroscopy with chronopotentiometry to observe directly the relationship between graphite deposited on nickel cermet anodes and the electrochemical performance of SOFCs operating at 725 °C. Raman spectra from Ni cermet anodes at open circuit voltage exposed to methane show a strong vibrational band at 1556 cm(-1) assigned to the "G" mode of highly ordered graphite. When polarized in the absence of a gas-phase fuel, these carbon-loaded anodes operate stably, oxidizing graphite to form CO and CO(2). Disappearance of graphite intensity measured in the Raman spectra is accompanied by a steep ∼0.8 V rise in the cell potential needed to keep the SOFC operating under constant current conditions. Continued operation leads to spectroscopically observable Ni oxidation and another steep rise in cell potential. Time-dependent spectroscopic and electrochemical measurements pass through correlated equivalence points providing unequivocal, in situ evidence that identifies how SOFC performance depends on the chemical condition of its anode. Chronopotentiometric data are used to quantify the oxide flux necessary to eliminate the carbon initially present on the SOFC anode, and data show that the oxidation mechanisms responsible for graphite removal correlate directly with the electrochemical condition of the anode as evidenced by voltammetry and impedance measurements. Electrochemically oxidizing the Ni anode damages the SOFC significantly and irreversibly. Anodes that have been reconstituted following electrochemical oxidation of

  8. Pyrosequencing Reveals High-Temperature Cellulolytic Microbial Consortia in Great Boiling Spring after In Situ Lignocellulose Enrichment

    PubMed Central

    Peacock, Joseph P.; Cole, Jessica K.; Murugapiran, Senthil K.; Dodsworth, Jeremy A.; Fisher, Jenny C.; Moser, Duane P.; Hedlund, Brian P.

    2013-01-01

    To characterize high-temperature cellulolytic microbial communities, two lignocellulosic substrates, ammonia fiber-explosion-treated corn stover and aspen shavings, were incubated at average temperatures of 77 and 85°C in the sediment and water column of Great Boiling Spring, Nevada. Comparison of 109,941 quality-filtered 16S rRNA gene pyrosequences (pyrotags) from eight enrichments to 37,057 quality-filtered pyrotags from corresponding natural samples revealed distinct enriched communities dominated by phylotypes related to cellulolytic and hemicellulolytic Thermotoga and Dictyoglomus, cellulolytic and sugar-fermenting Desulfurococcales, and sugar-fermenting and hydrogenotrophic Archaeoglobales. Minor enriched populations included close relatives of hydrogenotrophic Thermodesulfobacteria, the candidate bacterial phylum OP9, and candidate archaeal groups C2 and DHVE3. Enrichment temperature was the major factor influencing community composition, with a negative correlation between temperature and richness, followed by lignocellulosic substrate composition. This study establishes the importance of these groups in the natural degradation of lignocellulose at high temperatures and suggests that a substantial portion of the diversity of thermophiles contributing to consortial cellulolysis may be contained within lineages that have representatives in pure culture. PMID:23555835

  9. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    SciTech Connect

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates an alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.

  10. Argon–germane in situ plasma clean for reduced temperature Ge on Si epitaxy by high density plasma chemical vapor deposition

    DOE PAGESBeta

    Douglas, Erica A.; Sheng, Josephine J.; Verley, Jason C.; Carroll, Malcolm S.

    2015-06-04

    We found that the demand for integration of near infrared optoelectronic functionality with silicon complementary metal oxide semiconductor (CMOS) technology has for many years motivated the investigation of low temperature germanium on silicon deposition processes. Our work describes the development of a high density plasma chemical vapor deposition process that uses a low temperature (<460 °C) in situ germane/argon plasma surface preparation step for epitaxial growth of germanium on silicon. It is shown that the germane/argon plasma treatment sufficiently removes SiOx and carbon at the surface to enable germanium epitaxy. Finally, the use of this surface preparation step demonstrates anmore » alternative way to produce germanium epitaxy at reduced temperatures, a key enabler for increased flexibility of integration with CMOS back-end-of-line fabrication.« less

  11. Investigation of phase evolution of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) by in situ synchrotron high-temperature powder diffraction

    SciTech Connect

    Ouyang, Xin; Huang, Saifang; Zhang, Weijun; Cao, Peng; Huang, Zhaohui; Gao, Wei

    2014-03-15

    In situ synchrotron X-ray powder diffraction was used to study the high-temperature phase evolution of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) precursors prepared via solid-state and sol–gel methods. After the precursors are heated to 1225 °C, the CCTO phase is the main phase observed in the calcined powder, with the presence of some minor impurities. Comparing the two precursors, we found that the onset temperature for the CCTO phase formation is 800 °C in the sol–gel precursor, lower than that in the solid-state precursor (875 °C). Intermediate phases were only observed in the sol–gel precursor. Both precursors are able to be calcined to sub-micrometric sized powders. Based on the synchrotron data along with differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the phase formation sequence and mechanism during calcination are proposed in this study. -- Graphical abstract: The in situ synchrotron HT-XRD patterns of CCTO sol–gel and solid-state precursor. Highlights: • Phase formation sequence/mechanism in two CCTO precursors has been established. • Formation temperature of CCTO via sol–gel method is lower than solid-state method. • Intermediate phases are only observed in the sol–gel precursor. • Both precursors are able to be calcined into sub-micrometric sized powders.

  12. Microstructure and high-temperature wear properties of in situ TiC composite coatings by plasma transferred arc surface alloying on gray cast iron

    NASA Astrophysics Data System (ADS)

    Zhao, Hang; Li, Jian-jun; Zheng, Zhi-zhen; Wang, Ai-hua; Huang, Qi-wen; Zeng, Da-wen

    2015-12-01

    In this work, an in situ synthesized TiC-reinforced metal matrix composite (MMC) coating of approximately 350-400 µm thickness was fabricated on a gray cast iron (GCI) substrate by plasma transferred arc (PTA) surface alloying of Ti-Fe alloy powder. Microhardness tests showed that the surface hardness increased approximately four-fold after the alloying treatment. The microstructure of the MMC coating was mainly composed of residual austenite, acicular martensite, and eutectic ledeburite. Scanning electron microscopy (SEM) and X-ray diffraction analyzes revealed that the in situ TiC particles, which were formed by direct reaction of Ti with carbon originally contained in the GCI, was uniformly distributed at the boundary of residual austenite in the alloying zone. Pin-on-disc high-temperature wear tests were performed on samples both with and without the MMC coating at room temperature and at elevated temperatures (473 K and 623 K), and the wear behavior and mechanism were investigated. The results showed that, after the PTA alloying treatment, the wear resistance of the samples improved significantly. On the basis of our analysis of the composite coatings by optical microscopy, SEM with energy-dispersive X-ray spectroscopy, and microhardness measurements, we attributed this improvement of wear resistance to the transformation of the microstructure and to the presence of TiC particles.

  13. Highly conductive graphene by low-temperature thermal reduction and in situ preparation of conductive polymer nanocomposites.

    PubMed

    Yang, Liping; Kong, Junhua; Yee, Wu Aik; Liu, Wanshuang; Phua, Si Lei; Toh, Cher Ling; Huang, Shu; Lu, Xuehong

    2012-08-21

    Polydopamine-coated graphene oxide (DGO) films exhibit electrical conductivities of 11,000 S m(-1) and 30,000 S m(-1) upon vacuum annealing at 130 °C and 180 °C, respectively. Conductive poly(vinyl alcohol)/graphene and epoxy/graphene nanocomposites show low percolation thresholds due to the excellent dispersibility of the DGO sheets and their effective in situ reduction. PMID:22797422

  14. In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.

    PubMed

    Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

    2013-01-01

    We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions. PMID:22676479

  15. Oil-Soluble Silver-Organic Molecule for in Situ Deposition of Lubricious Metallic Silver at High Temperatures.

    PubMed

    Desanker, Michael; Johnson, Blake; Seyam, Afif M; Chung, Yip-Wah; Bazzi, Hassan S; Delferro, Massimiliano; Marks, Tobin J; Wang, Q Jane

    2016-06-01

    A major challenge in lubrication technology is to enhance lubricant performance at extreme temperatures that exceed conventional engine oil thermal degradation limits. Soft noble metals such as silver have low reactivity and shear strength, which make them ideal solid lubricants for wear protection and friction reduction between contacting surfaces at high temperatures. However, achieving adequate dispersion in engine lubricants and metallic silver deposition over predetermined temperatures ranges presents a significant chemical challenge. Here we report the synthesis, characterization, and tribological implementation of the trimeric silver pyrazolate complex, [Ag(3,5-dimethyl-4-n-hexyl-pyrazolate)]3 (1). This complex is oil-soluble and undergoes clean thermolysis at ∼310 °C to deposit lubricious, protective metallic silver particles on metal/metal oxide surfaces. Temperature-controlled tribometer tests show that greater than 1 wt % loading of 1 reduces wear by 60% in PAO4, a poly-α-olefin lubricant base fluid, and by 70% in a commercial fully formulated 15W40 motor oil (FF oil). This silver-organic complex also imparts sufficient friction reduction so that the tribological transition from oil as the primary lubricant through its thermal degradation, to 1 as the primary lubricant, is experimentally undetectable. PMID:27163783

  16. An in situ neutron diffraction study of cation disordering in synthetic quandilite Mg{sub 2}tiO{sub 4} at high temperatures.

    SciTech Connect

    O'Neill, H. St. C.; Redfern, S. A. T.; Kesson, S.; Short, S.; Australian National Univ.; Univ. Cambridge

    2003-05-01

    Temperature-dependent cation order-disorder has been studied in many 2+ - 3+ oxide spinels but 4+ - 2+ spinels have been found to be either completely normal or completely inverse when examined at room temperature. Here we report the temperature dependence of the cation distribution in the 4-2 spinel synthetic qandilite (Mg{sub 2}TiO{sub 4}) from in situ time-of-flight neutron powder diffraction experiments to 1416 {sup o}C. At room temperature, Mg{sub 2}TiO{sub 4} is confirmed to have completely inverse cation distribution, with Ti atoms occupying half the octahedrally coordinated cation sites. Cation disordering becomes observable above about 900 {sup o}C, with 4% of the Ti occupying the tetrahedral site by 1416 {sup o}C. The rate of reordering on cooling is fast, such that high-temperature disorder is not preserved on cooling to room temperature. The thermodynamics of the change in cation distribution with temperature can be described by an enthalpy of Mg-Ti disorder of -46.1 {+-} 0.4 kJ/mol.

  17. Crystalline phase transition information induced by high temperature susceptibility transformations in bulk PMP-YBCO superconductor growth in-situ

    NASA Astrophysics Data System (ADS)

    Zhang, C. P.; Chaud, X.; Beaugnon, E.; Zhou, L.

    2015-01-01

    The dynamic susceptibility transformations of bulk HTSC PMP-YBCO growth have been investigated from 200 °C up to 1060 °C by the Faraday Balance in-situ. It revealed that the crystalline phase transitions of bulk PMP-YBCO growth in process. A new discovery of Y123 phase pre-formed then melted in heating stage has been found. It also discovered that Y123 crystal solidification started at 1004 °C in cooling stage. Before Y123 solidification the liquid phase CuO change to Cu2O reciprocally as well as the copper ion valence changed between divalent Cu2+ and trivalent Cu1+ each other. It was essential to keep quantities of CuO phase instead of the Cu2O for Y123 crystal solidification.

  18. Seasonal warming of Narragansett Bay and Rhode Island Sound in 1997: Advanced very high resolution radiometer sea surface temperature and in situ measurements

    NASA Astrophysics Data System (ADS)

    Fox, Mary Frances; Kester, Dana R.; Andrews, James E.; Magnuson, Andrea; Zoski, Cynthia G.

    2000-09-01

    The warming of Narragansett Bay and the offshore waters of Rhode Island Sound (RIS) and Buzzards Bay in the spring and early summer of 1997 was studied using in situ time series data and remotely sensed advanced very high resolution radiometer sea surface temperature (SST) satellite images. High-resolution SST images of the New England area were expanded to highlight Narragansett Bay and RIS. To validate this procedure, the remotely sensed data were compared to in situ data at the NOAA buoy in Buzzards Bay and at a spar buoy in mid-Narragansett Bay. The standard error (1.3°C) observed at the buoy in Narragansett Bay was slightly higher than that observed at the buoy in Buzzards Bay (1.0°C). A transect line down Narragansett Bay and into RIS and another across the entrance of Narragansett Bay and Buzzards Bay were extracted from the 47 images. A thermal front was observed at the mouth of the bay with the bay being warmer in the summer and cooler in the winter than the sound. Two areas of cold water were identified in the RIS transect: a cold water plume at the tip of Long Island and a second area near the Elizabeth Islands. We believe that both were caused by vertical mixing. There were three sources of in situ time series data to compare with the SST: (1) a spar buoy with sensors in the surface and bottom waters located near the middle of the Bay, (2) observations from a shore site near the mouth of the Bay, and (3) a National Oceanic and Atmospheric Administration buoy at the mouth of Buzzards Bay. Using the spar buoy data, we were able to calculate the vertical density gradient, and we found that salinity was more important than temperature in controlling the density structure at this site. Time series temperature data from the surface water in Buzzards Bay were almost identical to those observed in the bottom waters of Narragansett Bay, indicating that bottom water in the bay originates as surface water in RIS. Using a cooling event in the surface waters at

  19. In situ atomic force microscope study of high-temperature untwinning surface relief in Mn-Fe-Cu antiferromagnetic shape memory alloy

    SciTech Connect

    Wang, L.; Cui, Y. G.; Wan, J. F.; Rong, Y. H.; Zhang, J. H.; Jin, X.; Cai, M. M.

    2013-05-06

    The N-type untwinning surface relief associated with the fcc {r_reversible} fct martensitic transformation (MT) was observed in the Mn{sub 81.5}Fe{sub 14.0}Cu{sub 4.5} antiferromagnetic high-temperature shape memory alloy (SMA) by in situ atomic force microscopy. The measured untwinning relief angles ({theta}{sub {alpha}} Double-Vertical-Line {theta}{sub {beta}}) at the ridge and at the valley were different, and both angles were less than the conventional values. The surface relief exhibited good reversibility during heating and cooling because of the crystallographic reversibility of thermal-elastic SMAs. Untwinning shear was proposed as the main mechanism of the N-type surface relief. The order of the reverse MT was discussed based on the experimental measurements.

  20. In situ transesterification of highly wet microalgae using hydrochloric acid.

    PubMed

    Kim, Bora; Im, Hanjin; Lee, Jae W

    2015-06-01

    This study addresses in situ transesterification of highly wet microalgae with hydrochloric acid (HCl) as a catalyst. In situ transesterification was performed by heating the mixture of wet algal cells, HCl, methanol, and solvent in one pot, resulting in the fatty acid methyl ester (FAME) yield over 90% at 95°C. The effects of reaction variables of temperature, amounts of catalyst, reactant, and solvent, and type of solvents on the yield were investigated. Compared with the catalytic effect of H2SO4, in situ transesterification using HCl has benefits of being less affected by moisture levels that are as high as or above 80%, and requiring less amounts of catalyst and solvent. For an equimolar amount of catalyst, HCl showed 15wt.% higher FAME yield than H2SO4. This in situ transesterification using HCl as a catalyst would help to realize a feasible way to produce biodiesel from wet microalgae. PMID:25769690

  1. Dislocation generation related to micro-cracks in Si wafers: High temperature in situ study with white beam X-ray topography

    NASA Astrophysics Data System (ADS)

    Danilewsky, A.; Wittge, J.; Hess, A.; Cröll, A.; Allen, D.; McNally, P.; Vagovič, P.; Cecilia, A.; Li, Z.; Baumbach, T.; Gorostegui-Colinas, E.; Elizalde, M. R.

    2010-02-01

    The generation and propagation of dislocations in Si at high temperature is observed in situ with white beam X-ray topography. For the heating experiments a double ellipsoidal mirror furnace was installed at the Topo-Tomo beamline of the ANKA synchrotron light source, Research Centre Karlsruhe, Germany. Details of the experimental set-up and the first results on the occurrence of dislocations are presented. Artificial damage was generated in commercial (1 0 0) Si wafers using a nanoindenter with various loads. The applied forces for each set of indents were varied from 100 to 500 mN, respectively. After heating to approx. 790 °C large area transmission topographs were taken every 30 min which were then compared to room temperature topographs before and after heating. At the outset straight 60°-dislocations with b = a/2<1 1 0> originate from the 500 mN indents into the direction of the strongest temperature gradient. After 60 min at constant temperature an increase in the length and number of the dislocations in other directions is also observed. As a result of the continual thermal stressing dislocations develop from the 100 mN indents too.

  2. In situ high temperature X-Ray diffraction study of the phase equilibria in the UO2-PuO2-Pu2O3 system

    NASA Astrophysics Data System (ADS)

    Belin, Renaud C.; Strach, Michal; Truphémus, Thibaut; Guéneau, Christine; Richaud, Jean-Christophe; Rogez, Jacques

    2015-10-01

    The region of the U-Pu-O phase diagram delimited by the compounds UO2-PuO2-Pu2O3 is known to exhibit a miscibility gap at low temperature. Consequently, MOX fuels with a composition entering this region could decompose into two fluorite phases and thus exhibit chemical heterogeneities. The experimental data on this domain found in the literature are scarce and usually provided using DTA that is not suitable for the investigation of such decomposition phenomena. In the present work, new experimental data, i.e. crystallographic phases, lattice parameters, phase fractions and temperature of phase separation, were measured in the composition range 0.14 < Pu/(U + Pu) < 0.62 and 1.85 < O/(U + Pu) < 2 from 298 to 1750 K using a novel in situ high temperature X-ray diffraction apparatus. A very good agreement is found between the temperature of phase separation determined from our results and using the thermodynamic model of the U-Pu-O system based on the CALPHAD method. Also, the combined use of thermodynamic calculations and XRD results refinement proved helpful in the determination of the O/M ratio of the samples during cooling. The methodology used in the current work might be useful to investigate other oxides systems exhibiting a miscibility gap.

  3. In Situ Temperature Jump Dynamic Nuclear Polarization

    PubMed Central

    Joo, Chan-Gyu; Casey, Andrew; Turner, Christopher J.; Griffin, Robert G.

    2009-01-01

    Dynamic nuclear polarization is combined with temperature jump methods to develop a new 2D 13C- 13C NMR experiment that yields a factor or 100-170 increase insensitivity. The polaization step is performed at ∼100 K and the sample is subsequently melted with a 10.6 mm laser pulse to yield a sample with highly polarized 13C spins. 13C detected 2D 13C- 13C spectroscopy is performed in the usual manner. PMID:18942782

  4. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    SciTech Connect

    Haboub, Abdel; Nasiatka, James R.; MacDowell, Alastair A.; Bale, Hrishikesh A.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.

    2014-08-15

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.

  5. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography.

    PubMed

    Haboub, Abdel; Bale, Hrishikesh A; Nasiatka, James R; Cox, Brian N; Marshall, David B; Ritchie, Robert O; MacDowell, Alastair A

    2014-08-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C. PMID:25173271

  6. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    NASA Astrophysics Data System (ADS)

    Haboub, Abdel; Bale, Hrishikesh A.; Nasiatka, James R.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.; MacDowell, Alastair A.

    2014-08-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.

  7. In Situ Synthesis of Porous Carbons by Using Room-Temperature, Atmospheric-Pressure Dielectric Barrier Discharge Plasma as High-Performance Adsorbents for Solid-Phase Microextraction.

    PubMed

    Lin, Yao; Wu, Li; Xu, Kailai; Tian, Yunfei; Hou, Xiandeng; Zheng, Chengbin

    2015-09-21

    A one-step, template-free method is described to synthesize porous carbons (PCs) in situ on a metal surface by using a room-temperature, atmospheric-pressure dielectric barrier discharge (DBD) plasma. This method not only features high efficiency, environmentally friendliness, and low cost and simple equipment, but also can conveniently realize large-area synthesis of PCs by only changing the design of the DBD reactor. The synthesized PCs have a regulated nestlike morphology, and thus, provide a high specific surface area and high pore volume, which result in excellent adsorption properties. Its applicability was demonstrated by using a PC-coated stainless-steel fiber as a solid-phase microextraction (SPME) fiber to preconcentrate polycyclic aromatic hydrocarbons (PAHs) prior to analysis by gas chromatography with flame ionization detection (GC-FID). The results showed that the fiber exhibited excellent enrichment factors (4.1×10(4) to 3.1×10(5)) toward all tested PAHs. Thus, the PC-based SPME-GC-FID provides low limits of detection (2 to 20 ng L(-1)), good precision (<7.8%), and good recoveries (80-115%) for ultra-sensitive determination of PAHs in real water samples. In addition, the PC-coated fiber could be stable enough for more than 500 replicate extraction cycles. PMID:26267394

  8. Temperature dependence of Jc for in situ superconductors

    SciTech Connect

    Ostenson, J.E.; Finnemore, D.K.; Gibson, E.D.; Sue, J.J.; Verhoeven, J.D.

    1982-01-01

    The experiments reported in this study seek to define the temperature dependence of the critical current densities for in situ superconducting wire in order to be able to predict the response of magnets when they are treated to temperature excursions well above 4.2 K. Studies of flux pinning in Nb/sub 3/Sn in situ filaments have determined that core pinning at grain boundary surface locations is the dominant factor controlling the critical current density. On the premise that proximity coupling may become a more important factor in the loss of critical current densities at high temperatures than a grain boundary breakdown, and to test whether the breakdown of the proximity effect degrades those densities, samples were chosen in which the proximity effect would show most readily, that is, those samples which have, owing to coarsening, rather short filaments. The samples were prepared from a dendritic Cu-Nb alloy that contained 20 wt% Nb, wound on a 1.27 cm diameter mandrel, and tested. It was found that the critical current density drops by 10% per degree K increase.

  9. In situ Growth of NixCu1-x Alloy Nanocatalysts on Redox-reversible Rutile (Nb,Ti)O4 Towards High-Temperature Carbon Dioxide Electrolysis

    NASA Astrophysics Data System (ADS)

    Wei, Haoshan; Xie, Kui; Zhang, Jun; Zhang, Yong; Wang, Yan; Qin, Yongqiang; Cui, Jiewu; Yan, Jian; Wu, Yucheng

    2014-06-01

    In this paper, we report the in situ growth of NixCu1-x (x = 0, 0.25, 0.50, 0.75 and 1.0) alloy catalysts to anchor and decorate a redox-reversible Nb1.33Ti0.67O4 ceramic substrate with the aim of tailoring the electrocatalytic activity of the composite materials through direct exsolution of metal particles from the crystal lattice of a ceramic oxide in a reducing atmosphere at high temperatures. Combined analysis using XRD, SEM, EDS, TGA, TEM and XPS confirmed the completely reversible exsolution/dissolution of the NixCu1-x alloy particles during the redox cycling treatments. TEM results revealed that the alloy particles were exsolved to anchor onto the surface of highly electronically conducting Nb1.33Ti0.67O4 in the form of heterojunctions. The electrical properties of the nanosized NixCu1-x/Nb1.33Ti0.67O4 were systematically investigated and correlated to the electrochemical performance of the composite electrodes. A strong dependence of the improved electrode activity on the alloy compositions was observed in reducing atmospheres at high temperatures. Direct electrolysis of CO2 at the NixCu1-x/Nb1.33Ti0.67O4 composite cathodes was investigated in solid-oxide electrolysers. The CO2 splitting rates were observed to be positively correlated with the Ni composition; however, the Ni0.75Cu0.25 combined the advantages of metallic nickel and copper and therefore maximised the current efficiencies.

  10. In situ growth of Ni(x)Cu(1-x) alloy nanocatalysts on redox-reversible rutile (Nb,Ti)O₄ towards high-temperature carbon dioxide electrolysis.

    PubMed

    Wei, Haoshan; Xie, Kui; Zhang, Jun; Zhang, Yong; Wang, Yan; Qin, Yongqiang; Cui, Jiewu; Yan, Jian; Wu, Yucheng

    2014-01-01

    In this paper, we report the in situ growth of Ni(x)Cu(1-x) (x = 0, 0.25, 0.50, 0.75 and 1.0) alloy catalysts to anchor and decorate a redox-reversible Nb1.33Ti0.67O4 ceramic substrate with the aim of tailoring the electrocatalytic activity of the composite materials through direct exsolution of metal particles from the crystal lattice of a ceramic oxide in a reducing atmosphere at high temperatures. Combined analysis using XRD, SEM, EDS, TGA, TEM and XPS confirmed the completely reversible exsolution/dissolution of the Ni(x)Cu(1-x) alloy particles during the redox cycling treatments. TEM results revealed that the alloy particles were exsolved to anchor onto the surface of highly electronically conducting Nb1.33Ti0.67O4 in the form of heterojunctions. The electrical properties of the nanosized Ni(x)Cu(1-x)/Nb1.33Ti0.67O4 were systematically investigated and correlated to the electrochemical performance of the composite electrodes. A strong dependence of the improved electrode activity on the alloy compositions was observed in reducing atmospheres at high temperatures. Direct electrolysis of CO2 at the Ni(x)Cu(1-x)/Nb1.33Ti0.67O4 composite cathodes was investigated in solid-oxide electrolysers. The CO2 splitting rates were observed to be positively correlated with the Ni composition; however, the Ni0.75Cu0.25 combined the advantages of metallic nickel and copper and therefore maximised the current efficiencies. PMID:24889679

  11. In situ Growth of NixCu1-x Alloy Nanocatalysts on Redox-reversible Rutile (Nb,Ti)O4 Towards High-Temperature Carbon Dioxide Electrolysis

    PubMed Central

    Wei, Haoshan; Xie, Kui; Zhang, Jun; Zhang, Yong; Wang, Yan; Qin, Yongqiang; Cui, Jiewu; Yan, Jian; Wu, Yucheng

    2014-01-01

    In this paper, we report the in situ growth of NixCu1-x (x = 0, 0.25, 0.50, 0.75 and 1.0) alloy catalysts to anchor and decorate a redox-reversible Nb1.33Ti0.67O4 ceramic substrate with the aim of tailoring the electrocatalytic activity of the composite materials through direct exsolution of metal particles from the crystal lattice of a ceramic oxide in a reducing atmosphere at high temperatures. Combined analysis using XRD, SEM, EDS, TGA, TEM and XPS confirmed the completely reversible exsolution/dissolution of the NixCu1-x alloy particles during the redox cycling treatments. TEM results revealed that the alloy particles were exsolved to anchor onto the surface of highly electronically conducting Nb1.33Ti0.67O4 in the form of heterojunctions. The electrical properties of the nanosized NixCu1-x/Nb1.33Ti0.67O4 were systematically investigated and correlated to the electrochemical performance of the composite electrodes. A strong dependence of the improved electrode activity on the alloy compositions was observed in reducing atmospheres at high temperatures. Direct electrolysis of CO2 at the NixCu1-x/Nb1.33Ti0.67O4 composite cathodes was investigated in solid-oxide electrolysers. The CO2 splitting rates were observed to be positively correlated with the Ni composition; however, the Ni0.75Cu0.25 combined the advantages of metallic nickel and copper and therefore maximised the current efficiencies. PMID:24889679

  12. A multipurpose ultra-high vacuum-compatible chamber for in situ X-ray surface scattering studies over a wide range of temperature and pressure environment conditions

    NASA Astrophysics Data System (ADS)

    Ferrer, P.; Rubio-Zuazo, J.; Heyman, C.; Esteban-Betegón, F.; Castro, G. R.

    2013-03-01

    A low/high temperature (60-1000K) and pressure (10-10-3x103 mbar) "baby chamber", specially adapted to the grazing-incidence X-ray scattering station, has been designed, developed and installed at the Spanish CRG BM25 SpLine beamline at European Synchrotron Radiation Facility. The chamber has a cylindrical form with 100 mm of diameter, built on a 360° beryllium nipple of 150 mm height. The UHV equipment and a turbo pump are located on the upper part of the chamber to leave a wide solid angle for exploring reciprocal space. The chamber features 4 CF16 and 5 CF40 ports for electrical feed through and leak valves, ion gun, etc. The heat exchanger is a customized compact LN2 (or LHe) continuous flow cryostat. The sample is mounted on a Mo support on the heat exchanger, which has in the back side a BORALECTRIC® Heater Elements. Experiments of surfaces/interfaces/ multilayer materials, thin films or single crystals in a huge variety of environments can be performed, also in situ studies of growth or evolution of the samples. Data measurement can be collected with a punctual and a bi-dimensional detector, being possible to simultaneously use them.

  13. A large-volume high-pressure and high-temperature apparatus for in situ X-ray observation, ' SPEED-Mk.II'

    NASA Astrophysics Data System (ADS)

    Katsura, Tomoo; Funakoshi, Ken-ichi; Kubo, Atsushi; Nishiyama, Norimasa; Tange, Yoshinori; Sueda, Yu-ichiro; Kubo, Tomoaki; Utsumi, Wataru

    2004-06-01

    SPEED-Mk.II, the second KAWAI-type high P- T apparatus for in situ X-ray observation that was installed at the bending magnet beam line at SPring-8, is described. The guide block system was designed so that the change of the relative dimension of the cubic compression space with press load can be minimized by repeated adjustments. The hydraulic system was designed so as to enable smooth compression and decompression. These precise controls should be advantageous for high-pressure generation, especially when sintered diamond (SD) anvils are used. An oscillation system was equipped for the first time in a large volume press, making it possible to obtain high-quality diffraction patterns even when the number of sample grains is limited. The use of the oscillation system also reduces errors in pressure determination that may be caused by insufficient averaging of diffraction angles over grains in a limited diffraction volume, because the oscillating grains should sweep through the 2 θ range that is allowed by the finite widths of the optical slits.

  14. Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies.

    PubMed

    Kline, David I; Teneva, Lida; Hauri, Claudine; Schneider, Kenneth; Miard, Thomas; Chai, Aaron; Marker, Malcolm; Dunbar, Rob; Caldeira, Ken; Lazar, Boaz; Rivlin, Tanya; Mitchell, Brian Gregory; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-01-01

    Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC) and total alkalinity (TA), rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 - 6.6°C) and lowest diel ranges (0.9 - 3.2°C) were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 - 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall) to December (end of Spring). Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems. PMID:26039687

  15. Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies

    PubMed Central

    Kline, David I.; Teneva, Lida; Hauri, Claudine; Schneider, Kenneth; Miard, Thomas; Chai, Aaron; Marker, Malcolm; Dunbar, Rob; Caldeira, Ken; Lazar, Boaz; Rivlin, Tanya; Mitchell, Brian Gregory; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-01-01

    Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC) and total alkalinity (TA), rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 – 6.6°C) and lowest diel ranges (0.9 – 3.2°C) were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 – 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall) to December (end of Spring). Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems. PMID:26039687

  16. In Situ Measurement of the γ/ γ' Lattice Mismatch Evolution of a Nickel-Based Single-Crystal Superalloy During Non-isothermal Very High-Temperature Creep Experiments

    NASA Astrophysics Data System (ADS)

    Le Graverend, Jean-Briac; Dirand, Laura; Jacques, Alain; Cormier, Jonathan; Ferry, Olivier; Schenk, Thomas; Gallerneau, Franck; Kruch, Serge; Mendez, José

    2012-11-01

    The evolution of the γ/ γ' lattice mismatch of the AM1 single-crystal superalloy was measured during in situ non-isothermal very high-temperature creep tests under X-ray synchrotron radiation. The magnitude of the effective lattice mismatch in the 1273 K to 1323 K (1000 °C to 1050 °C) temperature range always increased after overheatings performed at temperatures lower than 1403 K (1130 °C). In contrast, a decrease of its magnitude was observed after overheatings at temperatures greater than 1453 K (1180 °C) due to massive dislocation recovery processes occurring at very high temperature.

  17. Determination of the Phase Boundary Fe3O4 - h-Fe3O4 at high Temperature and Pressure using in situ Synchroton Radiation

    NASA Astrophysics Data System (ADS)

    Schollenbruch, K.; Woodland, A. B.; Frost, D. J.; Wang, Y.; Sanehira, T.

    2009-12-01

    Magnetite is an important accessory mineral in the Earth’s mantle and its rare occurrence as inclusions in diamonds means that this phase has a direct relevance to geochemical processes in the deep earth. For this reason it is important to define its thermodynamic behaviour at high P and T. Magnetite transforms to an orthorhombic high-pressure phase (h-Fe3O4) at room T and ~25 GPa, however the reaction is very sluggish and h-Fe3O4 is unquenchable, complicating the determination of the exact position of the phase boundary at low T. For this reason the phase transition has been investigated by a combination of a multianvil press and in situ X-ray diffraction measurements performed at the Advanced Photo Source (APS) at Argonne National Laboratory, U.S.A.. With this setup, pressure can be monitored during an experiment, allowing different P-T trajectories to be employed (i.e. pressurisation at high T) compared to conventional methods. Experiments were performed up to 15 GPa and 1400°C. A series of measurements during pressurisation at different temperatures revealed, that diffraction peaks related to h-Fe3O4 appeared at the expense of magnetite peaks at about 10 GPa. At the onset of the phase transition, the pressure decreased slightly due to pressure buffering from the 7% volume reduction attending the transition. However, the strongest magnetite reflections remained even at the highest P and T, underlining the sluggishness of the reaction. Measurements made while tracking down P at high T provided reversals, where the regrowth of magnetite diffraction peaks were observed. Once formed, h-Fe3O4 remains metastable down to nearly ambient conditions. Post-experiment TEM investigation revealed extensive twinning and other microstructures, confirming the interpretation of Frost et al. (2001), that such structures formed during the reconversion to magnetite at low pressure. Our high P-T experiments indicate a nearly isobaric phase boundary over a range of 800-1400

  18. Evidence for high-temperature in situ nifH transcription in an alkaline hot spring of Lower Geyser Basin, Yellowstone National Park.

    PubMed

    Loiacono, Sara T; Meyer-Dombard, D'Arcy R; Havig, Jeff R; Poret-Peterson, Amisha T; Hartnett, Hilairy E; Shock, Everett L

    2012-05-01

    Genes encoding nitrogenase (nifH) were amplified from sediment and photosynthetic mat samples collected in the outflow channel of Mound Spring, an alkaline thermal feature in Yellowstone National Park. Results indicate the genetic capacity for nitrogen fixation over the entire range of temperatures sampled (57.2°C to 80.2°C). Amplification of environmental nifH transcripts revealed in situ expression of nifH genes at temperatures up to 72.7°C. However, we were unable to amplify transcripts of nifH at the higher-temperature locations (> 72.7°C). These results indicate that microbes at the highest temperature sites contain the genetic capacity to fix nitrogen, yet either do not express nifH or do so only transiently. Field measurements of nitrate and ammonium show fixed nitrogen limitation as temperature decreases along the outflow channel, suggesting nifH expression in response to the downstream decrease in bioavailable nitrogen. Nitrogen stable isotope values of Mound Spring sediment communities further support geochemical and genetic data. DNA and cDNA nifH amplicons form several unique phylogenetic clades, some of which appear to represent novel nifH sequences in both photosynthetic and chemosynthetic microbial communities. This is the first report of in situ nifH expression in strictly chemosynthetic zones of terrestrial (non-marine) hydrothermal systems, and sets a new upper temperature limit (72.7°C) for nitrogen fixation in alkaline, terrestrial hydrothermal environments. PMID:22404902

  19. Chemistry at high pressures and temperatures: in-situ synthesis and characterization of {beta}-Si{sub 3}N{sub 4} by DAC X-ray/laser-heating studies

    SciTech Connect

    Yoo, C.-S.; Akella, J.; Nicol, M.

    1996-01-01

    We have developed in-situ XRD technique at high pressures and temperatures by integrating the angle-resolved synchrotron XRD method, laser-heating system, and diamond anvil cell together. Using this technique, we have studied the direct elementary reactions of nitrogen with Si, yielding technologically important {beta}-Si{sub 3}N{sub 4}. These reactions do not occur at ambient temperatures at high pressures up to 50 GPa, but proceed exothermically at high temperatures at moderate pressures. It implies that the reaction is kinetically limited by a large activation barrier.

  20. Isothermal nucleation and growth kinetics of Pd/Ag alloy phase via in-situ time-resolved high-temperature x-ray diffraction (HTXRD) analysis

    SciTech Connect

    Ayturk, Mahmut Engin; Payzant, E Andrew; Speakman, Scott A; Ma, Yi Hua

    2008-01-01

    Among several different approaches to form Pd/Ag alloys for hydrogen separation applications, ex-situ studies carried by conventional X-ray point scanning detectors might fail to reveal the key aspects of the phase transformation between Pd and Ag metals. In this respect, in-situ time-resolved high temperature X-ray diffraction (HTXRD) was employed to study the Pd/Ag alloy phase nucleation and growth kinetics. By the use of linear position sensitive detectors, advanced optics and profile fitting with the use of JADE-6.5 software, isothermal phase evolution of the Pd/Ag alloy at 500 C, 550 C and 600 C under hydrogen atmosphere were quantified to elucidate the mechanistic details of the Pd/Ag alloy phase nucleation and growth pattern. Analysis of the HTXRD data by the Avrami model indicated that the nucleation of the Pd/Ag alloy phase was instantaneous where the growth mechanism was through diffusion-controlled one-dimensional thickening of the Pd/Ag alloy layer. The value of the Avrami exponent, n, was found to increase with temperature with the values of 0.34, 0.39 and 0.67 at 500oC, 550oC and 600oC, respectively. In addition, parabolic rate law analysis suggested that the nucleation of the Pd/Ag alloy phase was through a heterogeneous nucleation mode, in which the nucleation sites were defined as the non-equilibrium defects. The cross-sectional SEI micrographs indicated that the Pd/Ag alloy phase growth was strongly dependent upon the deposition morphology of the as-synthesized Pd and Ag layers formed by the electroless plating. Based on the Avrami model and the parabolic rate law, the estimated activation energies for the phase transformation were 236.5 and 185.6 kJ/mol and in excellent agreement with the literature values (183-239.5 kJ/mol).

  1. An in situ synchrotron energy-dispersive diffraction study of the hydration of oilwell cement systems under high temperature/autoclave conditions up to 130 deg. C

    SciTech Connect

    Colston, Sally L.; Barnes, Paul . E-mail: p.barnes@bbk.ac.uk; Jupe, Andrew C.; Jacques, Simon D.M.; Hall, Christopher; Livesey, Paul; Dransfield, John; Meller, Nicola; Maitland, Geoffrey C.

    2005-12-15

    The technique of synchrotron energy dispersive diffraction has been developed for in situ studies of cement hydration under autoclave conditions. This has been applied to oilwell cements hydrating at typical oilwell temperatures up to 130 deg. C. The results show clearly the detailed interplay between 11 detectable phases, from which a phase transformation scheme has been derived; this illustrates the progression of hydration up to 130 deg. C for two extreme cases, with and without conservation of water content and autoclave pressure. The monosulphate hydrate phases are found to exhibit different stability bounds, with a surprising sequence of the 14-water, 10-water then 12-water monosulphate as temperature/time increases; the latter form is particularly associated with conditions of water/pressure loss. The effect of retarders on C{sub 3}S dissolution and CH formation is negligible above 70 deg. C, whereas the effect on the calcium sulphoaluminate hydrates is more complex, and possible reasons for this are discussed.

  2. Hybrid-type temperature sensor for in situ measurement

    SciTech Connect

    Iuchi, Tohru; Hiraka, Kensuke

    2006-11-15

    A hybrid-type surface temperature sensor combines the contact and noncontact methods, which allows us to overcome the shortcomings of both methods. The hybrid-type surface thermometer is composed mainly of two components: a metal film sheet that makes contact with an object and a radiometer that is used to detect the radiance of the rear surface of the metal film, which is actually a modified radiation thermometer. Temperature measurement using the hybrid-type thermometer with a several tens micrometer thick Hastelloy sheet, a highly heat and corrosion resistant alloy, is possible with a systematic error of -0.5 K and random errors of {+-}0.5 K, in the temperature range from 900 to 1000 K. This thermometer provides a useful means for calibration of in situ temperature measurement in various processes, especially in the silicon semiconductor industry. This article introduces the basic idea of the hybrid-type surface sensor, presents experimental results and discussions, and finally describes some applications.

  3. Determination of the phase boundary of the omega to beta transition in Zr using in situ high-pressure and high-temperature X-ray diffraction

    SciTech Connect

    Ono, Shigeaki; Kikegawa, Takumi

    2015-05-15

    The high-pressure behavior of zirconium has been examined using the synchrotron X-ray diffraction technique to a pressure of 38 GPa and a temperature of 800 K employing a hydrothermal diamond anvil cell technique. The structural transition from the ω to the β phase was observed. This transition has a negative dP/dT gradient, which is in general agreement with those reported in previous studies. The transition boundary was determined to be, P (GPa)=41.2–0.025×T (K). The negative slope of the transition, dP/dT, determined in our study using the diamond anvil cell technique was less than half that estimated by the previous study using a large press apparatus. - Graphical abstract: Experimental results and phase boundary of the ω–β transition in Zr. - Highlights: • X-ray diffraction patterns of zirconium were measured by the synchrotron experiments. • High-pressure experiments were performed by an external-heated diamond anvil cell. • Phase diagram of zirconium was determined at high pressures and high temperatures. • Phase boundary between omega and beta transition has a negative dP/dT slope.

  4. In situ determination of the spinel-post-spinel transition in Fe3O4 at high pressure and temperature by synchrotron X-ray diffraction

    SciTech Connect

    Schollenbruch, K; Woodland, A B; Frost, D J; Wang, Y; Sanehira, T; Langenhorst, F

    2011-08-10

    The position of the spinel-post-spinel phase transition in Fe3O4 has been determined in pressure-temperature space by in situ measurements using a multi-anvil press combined with white synchrotron radiation. Pressure measurement using the equation of state for MgO permitted pressure changes to be monitored at high temperature. The phase boundary was determined by the first appearance of diffraction peaks of the high-pressure polymorph (h-Fe3O4) during pressure increase and the disappearance of these peaks on pressure decrease along several isotherms. We intersected the phase boundary over the temperature interval of 700-1400 ºC. The boundary is linear and nearly isobaric, with a slightly positive slope. Post-experiment investigation by TEM confirms that the reverse reaction from h-Fe 3O4 to magnetite during decompression leads to the formation of microtwins on the (311) plane in the newly formed magnetite. Observations made during the phase transition suggest that the transition has a pseudomartensitic character, explaining in part why magnetite persists at conditions well within the stability field of h-Fe3O4, even at high temperatures. This study emphasizes the utility of studying phase transitions in situ at simultaneously high temperatures and pressures since the reaction kinetics may not be favorable at room temperature.

  5. High Throughput In Situ XAFS Screening of Catalysts

    SciTech Connect

    Tsapatsaris, Nikolaos; Beesley, Angela M.; Weiher, Norbert; Tatton, Helen; Schroeder, Sven L. M.; Dent, Andy J.; Mosselmans, Frederick J. W.; Tromp, Moniek; Russu, Sergio; Evans, John; Harvey, Ian; Hayama, Shu

    2007-02-02

    We outline and demonstrate the feasibility of high-throughput (HT) in situ XAFS for synchrotron radiation studies. An XAS data acquisition and control system for the analysis of dynamic materials libraries under control of temperature and gaseous environments has been developed. The system is compatible with the 96-well industry standard and coupled to multi-stream quadrupole mass spectrometry (QMS) analysis of reactor effluents. An automated analytical workflow generates data quickly compared to traditional individual spectrum acquisition and analyses them in quasi-real time using an HT data analysis tool based on IFFEFIT. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on {gamma}-Al2O3, and for the in situ characterization of Au catalysts supported on Al2O3 and TiO2.

  6. High Throughput In Situ XAFS Screening of Catalysts

    NASA Astrophysics Data System (ADS)

    Tsapatsaris, Nikolaos; Beesley, Angela M.; Weiher, Norbert; Tatton, Helen; Dent, Andy J.; Mosselmans, Frederick J. W.; Tromp, Moniek; Russu, Sergio; Evans, John; Harvey, Ian; Hayama, Shu; Schroeder, Sven L. M.

    2007-02-01

    We outline and demonstrate the feasibility of high-throughput (HT) in situ XAFS for synchrotron radiation studies. An XAS data acquisition and control system for the analysis of dynamic materials libraries under control of temperature and gaseous environments has been developed. The system is compatible with the 96-well industry standard and coupled to multi-stream quadrupole mass spectrometry (QMS) analysis of reactor effluents. An automated analytical workflow generates data quickly compared to traditional individual spectrum acquisition and analyses them in quasi-real time using an HT data analysis tool based on IFFEFIT. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on γ-Al2O3, and for the in situ characterization of Au catalysts supported on Al2O3 and TiO2.

  7. Temperature Calibration for In Situ Environmental Transmission Electron Microscopy Experiments

    PubMed Central

    Winterstein, JP; Lin, PA; Sharma, R

    2016-01-01

    In situ environmental transmission electron microscopy (ETEM) experiments require specimen heating holders to study material behavior in gaseous environments at elevated temperatures. In order to extract meaningful kinetic parameters, such as activation energies, it is essential to have a direct and accurate measurement of local sample temperature. This is particularly important if the sample temperature might fluctuate, for example when room temperature gases are introduced to the sample area. Using selected-area diffraction (SAD) in an ETEM, the lattice parameter of Ag nanoparticles was measured as a function of the temperature and pressure of hydrogen gas to provide a calibration of the local sample temperature. SAD permits measurement of temperature to an accuracy of ± 30 °C using Ag lattice expansion. Gas introduction can cause sample cooling of several hundred degrees celsius for gas pressures achievable in the ETEM. PMID:26441334

  8. High-resolution in-situ thermal imaging of microbial mats at El Tatio Geyser, Chile shows coupling between community color and temperature

    NASA Astrophysics Data System (ADS)

    Dunckel, Anne E.; Cardenas, M. Bayani; Sawyer, Audrey H.; Bennett, Philip C.

    2009-12-01

    Microbial mats have spatially heterogeneous structured communities that manifest visually through vibrant color zonation often associated with environmental gradients. We report the first use of high-resolution thermal infrared imaging to map temperature at four hot springs within the El Tatio Geyser Field, Chile. Thermal images with millimeter resolution show drastic variability and pronounced patterning in temperature, with changes on the order of 30°C within a square decimeter. Paired temperature and visual images show that zones with specific coloration occur within distinct temperature ranges. Unlike previous studies where maximum, minimum, and optimal temperatures for microorganisms are based on isothermally-controlled laboratory cultures, thermal imaging allows for mapping thousands of temperature values in a natural setting. This allows for efficiently constraining natural temperature bounds for visually distinct mat zones. This approach expands current understanding of thermophilic microbial communities and opens doors for detailed analysis of biophysical controls on microbial ecology.

  9. 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.

  10. 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.

  11. Cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror

    SciTech Connect

    Yuan, Sheng Sam; Goldberg, Kenneth A.; Yashchuk, Valeriy V.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory; Macdougall, James; Mochi, Iacopo; Warwick, Tony

    2010-09-15

    At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in-situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. In this paper, we report an initial cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror. This cross-check provides a validation of the in-situ shearing interferometry currently under development at the ALS.

  12. In Situ Analysis of a High-Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Aust, Jeffrey F.; Cooper, John B.; Wise, Kent L.; Jensen, Brian J.

    1999-01-01

    The vibrational spectrum of a high-temperature (330 C) polymerization reaction was successfully monitored in real time with the use of a modulated fiber-optic Fourier transform (FT)-Raman spectrometer. A phenylethynyl-terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

  13. Combining Remote Temperature Sensing with in-Situ Sensing to Track Marine/Freshwater Mixing Dynamics.

    PubMed

    McCaul, Margaret; Barland, Jack; Cleary, John; Cahalane, Conor; McCarthy, Tim; Diamond, Dermot

    2016-01-01

    The ability to track the dynamics of processes in natural water bodies on a global scale, and at a resolution that enables highly localised behaviour to be visualized, is an ideal scenario for understanding how local events can influence the global environment. While advances in in-situ chem/bio-sensing continue to be reported, costs and reliability issues still inhibit the implementation of large-scale deployments. In contrast, physical parameters like surface temperature can be tracked on a global scale using satellite remote sensing, and locally at high resolution via flyovers and drones using multi-spectral imaging. In this study, we show how a much more complete picture of submarine and intertidal groundwater discharge patterns in Kinvara Bay, Galway can be achieved using a fusion of data collected from the Earth Observation satellite (Landsat 8), small aircraft and in-situ sensors. Over the course of the four-day field campaign, over 65,000 in-situ temperatures, salinity and nutrient measurements were collected in parallel with high-resolution thermal imaging from aircraft flyovers. The processed in-situ data show highly correlated patterns between temperature and salinity at the southern end of the bay where freshwater springs can be identified at low tide. Salinity values range from 1 to 2 ppt at the southern end of the bay to 30 ppt at the mouth of the bay, indicating the presence of a freshwater wedge. The data clearly show that temperature differences can be used to track the dynamics of freshwater and seawater mixing in the inner bay region. This outcome suggests that combining the tremendous spatial density and wide geographical reach of remote temperature sensing (using drones, flyovers and satellites) with ground-truthing via appropriately located in-situ sensors (temperature, salinity, chemical, and biological) can produce a much more complete and accurate picture of the water dynamics than each modality used in isolation. PMID:27589770

  14. High resolution in situ ultrasonic corrosion monitor

    DOEpatents

    Grossman, R.J.

    1984-01-10

    An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

  15. High resolution in situ ultrasonic corrosion monitor

    DOEpatents

    Grossman, Robert J.

    1985-01-01

    An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

  16. Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature

    SciTech Connect

    Miyagi, Lowell; Kanitpanyacharoen, Waruntorn; Kaercher, Pamela; Wenk, Hans-Rudolf; Alarcon, Eloisa Zepeda; Raju, Selva Vennila; Knight, Jason; MacDowell, Alastair; Williams, Quentin

    2013-02-15

    To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate and optimize conditions for combined resistive and laser heating. For example, in Run1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg{sub 0.9}Fe{sub 0.1})O in Run3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.

  17. Determination of the effect of different additives in coking blends using a combination of in situ high-temperature {sup 1}H NMR and rheometry

    SciTech Connect

    Miguel C. Diaz; Karen M. Steel; Trevor C. Drage; John W. Patrick; Colin E. Snape

    2005-12-01

    High-temperature {sup 1}H NMR and rheometry measurements were carried out on 4:1 wt/wt blends of a medium volatile bituminous coal with two anthracites, two petroleum cokes, charcoal, wood, a low-temperature coke breeze, tyre crumb, and active carbon to determine the effects on fluidity development to identify the parameters responsible for these effects during pyrolysis and to study possible relationships among the parameters derived from these techniques. Positive, negative, and neutral effects were identified on the concentration of fluid material. Small positive effects (ca. 5-6%) were caused by blending the coal with petroleum cokes. Charcoal, wood, and active carbon all exerted negative effects on concentration (18-27% reduction) and mobility (12-25% reduction in T2) of the fluid phase, which have been associated with the inert character and high surface areas of these additives that adsorb the fluid phase of the coal. One of the anthracites and the low-temperature coke breeze caused deleterious effects to a lesser extent on the concentration (7-12%) and mobility (13-17%) of the fluid material, possibly due to the high concentration of metals in these additives (ca. 11% ash). Despite the high fluid character of tyre crumb at the temperature of maximum fluidity of the coal (73%), the mobility of the fluid phase of the blend was lower than expected. The comparison of {sup 1}H NMR and rheometry results indicated that to account for the variations in minimum complex viscosity for all the blends, both the maximum concentration of fluid phase and the maximum mobility of the fluid material had to be considered. For individual blends, two exponential relationships have been found between the complex viscosity and the concentration of solid phase in both the softening and resolidification stages but the parameters are different for each blend. 30 refs., 8 figs., 5 tabs.

  18. Low-temperature in situ formation of Y-Ba-Cu-O high T sub c superconducting thin films by plasma-enhanced metalorganic chemical vapor deposition

    SciTech Connect

    Zhao, J.; Noh, D.W.; Chern, C.; Li, Y.Q.; Norris, P.; Gallois, B.; Kear, B. )

    1990-06-04

    Highly textured, highly dense, superconducting YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} thin films with mirror-like surfaces have been prepared, {ital in} {ital situ}, at a reduced substrate temperature as low as 570 {degree}C by a remote microwave plasma-enhanced metalorganic chemical vapor deposition process (PE-MOCVD). Nitrous oxide was used as the oxidizer gas. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K. PE-MOCVD was carried out in a commercial scale MOCVD reactor.

  19. In situ high-frequency observations of mycorrhizas.

    PubMed

    Allen, Michael F; Kitajima, Kuni

    2013-10-01

    Understanding the temporal variation of soil and root dynamics is a major step towards determining net carbon in ecosystems. We describe the installation and structure of an in situ soil observatory and sensing network consisting of an automated minirhizotron with associated soil and atmospheric sensors. Ectomycorrhizal hyphae were digitized daily during 2011 in a Mediterranean climate, high-elevation coniferous forest. Hyphal length was high, but stable during winter in moist and cold soil. As soil began to warm and dry, simultaneous mortality and production indicating turnover followed precipitation events. Mortality continued through the dry season, although some hyphae persisted through the extremes. With autumn monsoons, rapid hyphal re-growth occurred following each event. Relative hyphal length is dependent upon soil temperature and moisture. Soil respiration is related to the daily change in hyphal production, but not hyphal mortality. Continuous sensor and observation systems can provide more accurate assessments of soil carbon dynamics. PMID:23772913

  20. In-situ Raman spectroscopic study of aluminate speciation in H2O-KOH solutions at high pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Keppler, H.; Manning, C. E.

    2009-12-01

    The solubility of corundum in H2O is low even at high pressure and temperatures. Therefore, it is commonly assumed that alumina remains essentially immobile during fluid-rock interaction. However, field and experimental evidence suggests that alumina solubility is strongly enhanced in the presence of silica as well as in alkaline solutions. In order to understand what controls the alumina solubility and how it is enhanced as a function of fluid composition, we conducted Raman-spectroscopic study of Al speciation in aqueous fluids at high pressure and temperature. Experiments were carried out in an externally heated hydrothermal diamond-anvil cell equipped with low-fluorescence diamonds and iridium gaskets. Raman spectra were collected with a Horiba Jobin-Yvon Labram HR spectrometer using the 514 nm line of an argon laser for excitation. In a first series of experiments, the speciation of alumina was studied in a 1 M KOH solution in equilibrium with corundum up to 700 oC and ~1 GPa. The Raman spectra show a prominent band at 618 cm-1 interpreted to arise from Al-O stretching vibrations associated with the tetrahedral [Al(OH)4]1- species. At higher pressure and temperature, an additional vibrational mode appears in the spectra at 374 cm-1 (full width at half maximum ~ 20 cm-1). This feature is tentatively attributed to [(OH)3Al-O-Al(OH)3]2- (Moolenaar et al. 1970, Jour. Phys. Chem., 74, 3629-3636). No evidence for KAl(OH)4 was observed, consistent with piston cylinder experiments at 700 oC and 1 GPa (Wohlers & Manning, 2009, Chem. Geol., 262, 310). Upon cooling from high-pressure and high temperature, slow kinetics of corundum regrowth lead to oversaturation in the solutions, as evidenced by sharp peaks at 930 and 1066 cm-1 observed upon cooling. These features are probably due to colloidal aluminum hydroxide. The results provide the first evidence for aluminate polymerization at high pressure and temperature, and offer insights into the causes for enhancement of

  1. Low Temperature Regolith Bricks for In-Situ Structural Material

    NASA Technical Reports Server (NTRS)

    Grossman, Kevin; Sakthivel, Tamil S.; Mantovani, James; Seal, Sudipta

    2016-01-01

    Current technology for producing in-situ structural materials on future missions to Mars or the moon relies heavily on energy-intensive sintering processes to produce solid bricks from regolith. This process requires heating the material up to temperatures in excess of 1000 C and results in solid regolith pieces with compressive strengths in the range of 14000 to 28000 psi, but are heavily dependent on the porosity of the final material and are brittle. This method is currently preferred over a low temperature cementation process to prevent consumption of precious water and other non-renewable materials. A high strength structural material with low energy requirements is still needed for future colonization of other planets. To fulfill these requirements, a nano-functionalization process has been developed to produce structural bricks from regolith simulant and shows promising mechanical strength results. Functionalization of granular silicate particles into alkoxides using a simple low temperature chemical process produces a high surface area zeolite particles that are held together via inter-particle oxygen bonding. Addition of water in the resulting zeolite particles produces a sol-gel reaction called "inorganic polymerization" which gives a strong solid material after a curing process at 60 C. The aqueous solution by-product of the reaction is currently being investigated for its reusability; an essential component of any ISRU technology. For this study, two batches of regolith bricks are synthesized from JSC-1A; the first batch from fresh solvents and chemicals, the second batch made from the water solution by-product of the first batch. This is done to determine the feasibility of recycling necessary components of the synthesis process, mainly water. Characterization including BET surface area, SEM, and EDS has been done on the regolith bricks as well as the constituent particles,. The specific surface area of 17.53 sq m/g (average) of the granular regolith

  2. Isentropic advection and convective lifting of water vapor in the UT - LS as observed over Brazil (22° S) in February 2004 by in situ high-resolution measurements of H2O, CH4, O3 and temperature

    NASA Astrophysics Data System (ADS)

    Durry, G.; Huret, N.; Hauchecorne, A.; Marecal, V.; Pommereau, J.-P.; Jones, R. L.; Held, G.; Larsen, N.; Renard, J.-B.

    2006-12-01

    The micro-SDLA balloonborne diode laser spectrometer was flown twice from Bauru (22° S, Brazil) in February 2004 during HIBISCUS to yield in situ H2O measurements in the Upper Troposphere (UT) and Lower Stratosphere (LS) and in particular in the Tropical Tropopause Layer (TTL). The overall TTL was found warmer (with a subsaturated cold point near -79°C) and the LS moister compared to former measurements obtained in tropical oceanic conditions. The use of specific balloons with a slow descent, combined with the high-resolution of the laser sensor, allowed us to observe in situ in the UT, the TTL and the LS several thin layers correlated on H2O, CH4, O3, temperature and PV. A component of these layers is associated with the isentropic transport into the UT- LS of extratropical stratospheric air masses. Moreover, the examination of temperature and tracer (CH4, O3) profiles gives insights on the potential contribution of convective transport of H2O in the TTL.

  3. 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.

  4. In-Situ Measurement of Metal Drop Temperature in GMA Short-Circuiting Welding

    NASA Astrophysics Data System (ADS)

    Hirata, Yoshinori; Onda, Masahiko; Nagaki, Hayato; Ohji, Takayoshi

    Temperatures of metal drop in GMA short-circuiting welding process were in-situ measured using newly developed instrument designed on the basis of two-color pyrometry, which consisted of optical lenses, interference filters for two colors and two sets of high sensitive CCD cameras with fast shutter. In order to avoid radiation from arc plasma, temperature measurement was carried out immediately after molten drop at electrode wire tip was contacted with weld pool and arc was extinguished. Welding current in arcing period was adjusted from 50 A to 250 A using experimental power source in Ar + 20%CO2 mixture gas shielded GMA welding with mild steel wire of 1.2 mm in diameter. It is shown through in-situ measurement that average temperature of metal drop ranges from 2200 K to 2700 K, depending on level and period of arc current governing electrode wire melting.

  5. Multifunctional Nanowire/film Composites based Bi-modular Sensors for In-situ and Real-time High Temperature Gas Detection

    SciTech Connect

    Gao, Pu-Xian; Lei, Yu

    2013-06-01

    This final report to the Department of Energy/National Energy Technology Laboratory for DE-FE0000870 covers the period from 2009 to June, 2013 and summarizes the main research accomplishments, which can be divided in sensing materials innovation, bimodular sensor demonstration, and new understanding and discoveries. As a matter of fact, we have successfully completed all the project tasks in June 1, 2013, and presented the final project review presentation on the 9th of July, 2013. Specifically, the major accomplishments achieved in this project include: 1) Successful development of a new class of high temperature stable gas sensor nanomaterials based on composite nano-array strategy in a 3D or 2D fashion using metal oxides and perovskite nanostructures. 2) Successful demonstration of bimodular nanosensors using 2D nanofibrous film and 3D composite nanowire arrays using electrical resistance mode and electrochemical electromotive force mode. 3) Series of new discoveries and understandings based on the new composite nanostructure platform toward enhancing nanosensor performance in terms of stability, selectivity, sensitivity and mass flux sensing. In this report, we highlight some results toward these accomplishments.

  6. In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells

    PubMed Central

    Yamamoto, Kazuhiro; Qiu, Nan; Ohara, Satoshi

    2015-01-01

    A core–shell anode consisting of nickel–gadolinium-doped-ceria (Ni–GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm–2, which is higher than that of a conventional NiO–GDC anode prepared by an aerosol process at 55 mW cm–2 and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni–GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully. PMID:26615816

  7. In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells.

    PubMed

    Yamamoto, Kazuhiro; Qiu, Nan; Ohara, Satoshi

    2015-01-01

    A core-shell anode consisting of nickel-gadolinium-doped-ceria (Ni-GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm(-2), which is higher than that of a conventional NiO-GDC anode prepared by an aerosol process at 55 mW cm(-2) and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully. PMID:26615816

  8. In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuhiro; Qiu, Nan; Ohara, Satoshi

    2015-11-01

    A core-shell anode consisting of nickel-gadolinium-doped-ceria (Ni-GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm-2, which is higher than that of a conventional NiO-GDC anode prepared by an aerosol process at 55 mW cm-2 and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni-GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

  9. Wireless device for monitoring the temperature - moisture regime in situ

    NASA Astrophysics Data System (ADS)

    Hudec, Ján; Štofanik, Vladimír; Vretenár, Viliam; Kubičár, Ľudovít

    2014-05-01

    This contribution presents the wireless device for monitoring the temperature - moisture regime in situ. For the monitoring so called moisture sensor is used. Principle of moisture sensor is based on measuring the thermal conductivity. Moisture sensor has cylindrical shape with about 20 mm diameter and 20 mm length. It is made of porous material identical to the monitored object. The thermal conductivity is measured by hot-ball method. Hot-ball method is patented invention of the Institute of Physic SAS. It utilizes a small ball, diameter up to 2 mm, in which sensing elements are incorporated. The ball produces heat spreading into surrounding material, in our case into body of the moisture sensor. Temperature of the ball is measured simultaneously. Then change of the temperature, in steady state, is inversely proportional to the thermal conductivity. Such moisture sensor is inserted into monitored wall. Thermophysical properties of porous material are function of moisture. Moisture sensors are calibrated for dry and water saturated state. Whole the system is primarily intended to do long-term monitoring. Design of a new electronic device was needed for this innovative method. It covers all needed operations for measurement. For example energizing hot-ball sensor, measuring its response, storing the measured data and wireless data transmission. The unit is able to set parameters of measurement via wireless access as well. This contribution also includes the description of construction and another features of the wireless measurement system dedicated for this task. Possibilities and functionality of the system is demonstrated by actual monitoring of the tower of St. Martin's Cathedral in Bratislava. Correlations with surrounding meteorological conditions are presented. Some of them can be also measured by our system, right in the monitoring place.

  10. Oil-Well Cement and C3S Hydration Under High Pressure as Seen by In Situ X-Ray Diffraction, Temperatures ;= 80 degrees C with No Additives

    SciTech Connect

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Garry P.

    2012-06-28

    The hydration kinetics of a white cement and batches of both Class G and H oil-well cements were examined between 0 and 60 MPa, at {le}80 C, using in situ synchrotron X-ray diffraction. This gives a continuous measure of the C{sub 3}S (Ca{sub 3}SiO{sub 5}), CH (Ca(OH){sub 2}), C{sub 4}AF (Ca{sub 2}FeAlO{sub 5}), ettringite, and other phases in the hydrating slurries. Slurries prepared from single-phase C{sub 3}S; synthetic C{sub 4}AF, and gypsum; and white cement, synthetic C{sub 4}AF and gypsum were also examined. An increasing pressure enhanced the rate of hydration for all slurries. Analysis of the data, using a kinetic model, provided rate constants that were used to obtain activation volumes for C{sub 3}S hydration. For all the cement and C{sub 3}S slurries studied, similar activation volumes were obtained (average {Delta}V{double_dagger}{sup -}-35 cm{sup 3}/mol), indicating that the presence of cement phases other than C{sub 3}S has a modest influence on the pressure dependence of C{sub 3}S hydration. An alternative analysis, using the time at which 90% of the initial C{sub 3}S remained, gave similar activation volumes. Pressure accelerated the formation of ettringite from synthetic C{sub 4}AF in the presence of gypsum. However, in slurries containing cement, the pressure dependence of C{sub 3}S hydration plays a major role in determining the pressure dependence of ettringite formation.

  11. In Situ Monitoring of Temperature inside Lithium-Ion Batteries by Flexible Micro Temperature Sensors

    PubMed Central

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ. PMID:22163735

  12. In situ monitoring of temperature inside lithium-ion batteries by flexible micro temperature sensors.

    PubMed

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ. PMID:22163735

  13. Development of Self-Powered Wireless-Ready High Temperature Electrochemical Sensors for In-Situ Corrosion Monitoring for Boiler Tubes in Next Generation Coal-based Power Systems

    SciTech Connect

    Liu, Xingbo

    2015-06-30

    The key innovation of this project is the synergy of the high temperature sensor technology based on the science of electrochemical measurement and state-of-the-art wireless communication technology. A novel self-powered wireless high temperature electrochemical sensor system has been developed for coal-fired boilers used for power generation. An initial prototype of the in-situ sensor demonstrated the capability of the wireless communication system in the laboratory and in a pilot plant (Industrial USC Boiler Setting) environment to acquire electrochemical potential and current signals during the corrosion process. Uniform and localized under-coal ash deposit corrosion behavior of Inconel 740 superalloy has been studied at different simulated coal ash hot corrosion environments using the developed sensor. Two typical potential noise patterns were found to correlate with the oxidation and sulfidation stages in the hot coal ash corrosion process. Two characteristic current noise patterns indicate the extent of the corrosion. There was a good correlation between the responses of electrochemical test data and the results from corroded surface analysis. Wireless electrochemical potential and current noise signals from a simulated coal ash hot corrosion process were concurrently transmitted and recorded. The results from the performance evaluation of the sensor confirm a high accuracy in the thermodynamic and kinetic response represented by the electrochemical noise and impedance test data.

  14. Structural behavior of Al 3+ in silicate melts: In situ, high-temperature measurements as a function of bulk chemical composition

    NASA Astrophysics Data System (ADS)

    Mysen, Bjorn

    1995-02-01

    The anionic structure of aluminosilicate melts has been determined along the join Li 2Si 2O 5Li 2(LiAl) 2O 5 (LS2-LA2) with microRaman spectroscopy in the temperature range 25°-1460°C. Those data are compared with the structural behavior of melts along the join Na 2Si 2O 5Na 2(NaAl) 2O 5 (NS2-NA2) in the same temperature interval. In these systems, Li' and Na + serve both to charge-balance Al 3+ in tetrahedral coordination and as network-modifiers. The NBO/ T ( T = Si + Al) equals unity in the Al/(Al + Si) range examined (0-0.3). In the Al-free endmember glass and melt systems, the three species, Q4, Q3, and Q2 coexist and the expression, (1) 2 Q3 ⇔ Q2 + Q4, describes the equilibrium. Substitution of Na- or Li-charge-balanced Al 3+ for Si 4+ results in stabilization of an additional, more depolymerized structural unit, Q1. An additional equilibrium, (2) 2 Q2 ⇔ Q1 + Q3, is needed, therefore, for a complete description of the equilibria. In the LS2-LA2 system, the ΔH for this latter reaction ( ΔH2) ranges between ˜0 and -87 kJ/mol and is negatively correlated with Al/(Al + Si). In the NS2-NA2 system, the ΔH2 is positive with values between 16 and 37 kJ/mol and is positively correlated with Al/(Al + Si). Equilibrium (1) is affected by equilibrium (2) in the Al-bearing melts, so that in the NS2-NA2 melt system, equilibrium (1) shifts to the left with temperature ( ΔH1 = -10--15 kJ/mol), whereas in the LS2-LA2 system, equilibrium (1) shifts more strongly to the right with temperature than in the absence of Al ( ΔH1 is positively correlated with Al/(Al + Si) with values in the range 6-48 kJ/mol). Activity coefficients for Q2 units in the melts calculated from liquidus phase relations in combination with the determined mol fractions of structural units in the melts show simple relations between activity coefficient of the unit and its molar abundance in the melts.

  15. In situ visualisation of electromigration in Pt nanobridges at elevated temperatures.

    PubMed

    Kozlova, Tatiana; Zandbergen, Henny W

    2015-11-01

    We used a combination of in situ TEM, a MEMS-based heater as a substrate and a dedicated biasing sample holder to study the temperature dependence of electromigration in Pt nanobridges (500 nm wide, 15 nm high and 1000 nm long). We visualised changes in the nanobridges under both dynamic conditions, i.e. heating (substrate temperatures up to 660 K) and current passage. Our electromigration experiments at various substrate temperatures (100, 300, 420 and 660 K) show the same tendency: material transport occurs from the cathode to the anode side, which can be explained by the electron-wind force. In all cases the bridge breaks due to the formation of a neck closer to the cathode side. At 300, 420 and 660 K, voids and the neck form at the cathode contact pad simultaneously. The higher the temperature, the bigger the voids size. As expected, at higher temperatures a lower power is needed to break the nanobridge. PMID:26202895

  16. In situ strain and temperature measurement and modelling during arc welding

    DOE PAGESBeta

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; Feng, Zhili

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well asmore » a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.« less

  17. In situ strain and temperature measurement and modelling during arc welding

    SciTech Connect

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; Feng, Zhili

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well as a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.

  18. A Low-Cost, In Situ Resistivity and Temperature Monitoring System

    EPA Science Inventory

    We present a low-cost, reliable method for long-term in situ autonomous monitoring of subsurface resistivity and temperature in a shallow, moderately heterogeneous subsurface. Probes, to be left in situ, were constructed at relatively low cost with close electrode spacing. Once i...

  19. Calcium pyroxenes at Mercurian surface temperatures: investigation of in-situ emissivity spectra and thermal expansion

    NASA Astrophysics Data System (ADS)

    Ferrari, S.; Nestola, F.; Helbert, J.; Maturilli, A.; D'Amore, M.; Alvaro, M.; Domeneghetti, M.; Massironi, M.; Hiesinger, H.

    2013-12-01

    The European Space Agency and Japan Aerospace Agency mission to Mercury, named BepiColombo, will carry on board the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) that will be able to provide surface Thermal Infra-Red (TIR) emissivity spectra from 7 to 14 μm. This range of wavelengths is very useful to identify the fine-scale structural properties of several silicates. For mineral families as pyroxenes, the emissivity peak positions are good indicators of the composition. A complication in the interpretation of MERTIS data could arise from the extreme daily surface temperature range of Mercury (70 to 725 K) that significantly affects the crystal structure and density of minerals and consequently should affect the TIR spectral signature of each single mineral present on the surface of the planet. In preparation for the MERTIS data analysis, we are extensively investigating at high temperatures conditions several mineral phases potentially detectable on the surface of Mercury. Two C2/c augitic pyroxenes, with constant calcium content and very different magnesium to iron ratio, were studied by in situ high-temperature thermal infrared spectroscopy (up to 750 K) and in situ high-temperature single-crystal X-ray diffraction (up to 770 K). The emissivity spectra of the two samples show similar band center shifts of the main three bands toward lower wavenumbers with increasing temperature. Our results indicate that the center position of bands 1 and 2 is strictly dependent on temperature, whereas the center position of band 3 is a strong function of the composition regardless the temperature. These data suggest that MERTIS spectra will be able to provide indications of C2/c augitic pyroxene with different magnesium contents and will allow a correct interpretation independently on the spectra acquisition temperature.

  20. In situ study of the fractionation of hydrogen isotopes between aluminosilicate melts and coexisting aqueous fluids at high pressure and high temperature - Implications for the δD in magmatic processes

    NASA Astrophysics Data System (ADS)

    Dalou, Célia; Le Losq, Charles; Mysen, Bjorn O.

    2015-09-01

    The hydrogen isotopic composition of melt inclusions trapped in phenocrysts during their crystallization and growth in a magma may contribute to a better understanding of the water cycle between the atmosphere, the hydrosphere and the lithosphere. Such understanding relies on the knowledge of the hydrogen isotopic fractionation factors between aqueous fluids, silicate melts, and minerals at temperature and pressure conditions relevant to the Earth's interior. Significant D/H fractionation between silicate melts and aqueous fluids was reported at hundreds of MPa and °C by using in situ measurements in hydrothermal diamond anvil cell (HDAC) experiments (Mysen, 2013a, 2013b, Am. Mineral. 98, 376-386 and 1754-1764). However, the available dataset is focused on fluids and melts with D/H ratios close to unity. The relevance of such data for natural processes that involve per mil variations of δD-values may not always be clear. To address such concerns, the effect of the bulk D/H ratio on hydrogen isotope partitioning between water-saturated silicate melts and coexisting silicate-saturated aqueous fluids has been determined in the Na2O-Al2O3-SiO2-H2O-D2O system. To this end, in situ Raman spectroscopic measurements were performed on fluids and melts with bulk D/H ratios from 0.05 to 2.67 by using an externally-heated diamond anvil cell in the 300-800 °C and 200-1500 MPa temperature and pressure range, respectively. In these pressure/temperature ranges, the D/H ratios of fluids in equilibrium with melt barely change with temperature (in average ΔHfluid = 0.47 ± 1.15 kJ /mol). In contrast, the D/H ratios of coexisting melts display strong dependence on temperature (average ΔHmelt = 7.18 ± 1.27 kJ /mol). The temperature-dependence of the D/H fractionation factor between melt and fluid (αfluid-melt = D /Hfluid / D /Hmelt) is comparable in all the experiments and can be written: 1000 ṡ ln ⁡ (αfluid-melt) = 263 (± 26) ṡT-2- 126 (± 48). Therefore, the

  1. In Situ Thermal Ion Temperature Measurements in the E Region Ionosphere: Techniques, Results, and Limitations

    NASA Astrophysics Data System (ADS)

    Burchill, J. K.; Archer, W. E.; Clemmons, J. H.; Knudsen, D. J.; Nicolls, M. J.

    2011-12-01

    In situ measurements of thermal ion temperature are rare at E region altitudes, which are too low for satellites. Here we present ion temperature measurements from a Thermal Ion Imager (TII) that flew on NASA sounding rocket 36.234 (the "Joule-2" mission) into the nightside E region ionosphere on 19 January 2007 from Poker Flat, AK. The TII is an electrostatic ion energy/angle imager that provides 2D ion distributions at 8 ms resolution. Ion temperatures are derived at altitudes between 100 km and 190 km by modelling the detector total count rate versus ion bulk flow angle with respect to the plane of the imager's field of view. Modelling this count rate spin profile shows that the analysis technique is robust against a number of error sources, including variability in payload floating potential, ion upflow, and aperture widening due to reflections from electrode surfaces. A significant uncertainty is associated with the average mass of the ions, which is not measured independently. Using the International Reference Ionosphere model to estimate ion mass, we obtain an ion temperature of 1300 K at 125 km, increasing to more than 3000 K at 180 km. These temperatures are much larger than neutral temperatures obtained from an ionization gauge on the same rocket (Tn˜500 K at 125 km, ˜600 K at 180 km), and do not agree with incoherent scatter radar observations in the vicinity of the rocket. These anomalous ion temperatures are, however, consistent with results from an independent analysis of the shape of the ion distribution images from a similar instrument on a separate payload flown 10 minutes earlier [Archer, MSc Thesis, University of Calgary, 2009]. We conclude that the high ion temperature readings are an artifact related to the environment in the vicinity of the probe, and investigate mechanisms for the cause. We discuss the implications of this effect for future in situ attempts to measure ion temperature in the E region ionosphere.

  2. In situ X-ray diffraction study of structural evaluation in Fe73Cu1.5Nd3Si13.5B9 amorphous alloy at high temperature

    NASA Astrophysics Data System (ADS)

    Li, Gong; Xu, Tao; Gao, Yunpeng; Liu, Riping

    2008-04-01

    The thermodynamics structural relaxation of Fe73Cu1.5Nd3Si13.5B9 amorphous alloy from room temperature to 400°C has been investigated by measuring the structure factor with in situ X-ray diffraction. The structural information of the atomic configuration such as radial distribution function (RDF) and neighbor atomic distance was gained by Fourier transformation. The research result shows that the amorphous structure remains stable in the temperature range of 30 to 400°C but exhibits distinct changes in local atomic configuration with the increase of temperature. The quantitative determination of the neighbor atomic distance suggests that the degree of short-range order changes by the temperature altering the second nearest neighbor local atomic configuration of the amorphous when structural relaxation occurs.

  3. In situ thermal imaging and absolute temperature monitoring by luminescent diphenylalanine nanotubes.

    PubMed

    Gan, Zhixing; Wu, Xinglong; Zhang, Jinlei; Zhu, Xiaobin; Chu, Paul K

    2013-06-10

    The temperature sensing capability of diphenylalanine nanotubes is investigated. The materials can detect local rapid temperature changes and measure the absolute temperature in situ with a precision of 1 °C by monitoring the temperature-dependent photoluminescence (PL) intensity and lifetime, respectively. The PL lifetime is independent of ion concentrations in the medium as well as pH in the physiological range. This biocompatible thermal sensing platform has immense potential in the in situ mapping of microenvironmental temperature fluctuations in biological systems for disease diagnosis and therapeutics. PMID:23679829

  4. Mid-crust fluid and water-rock interaction kinetic experiments and their geophysical significance: 3. in situ measurements of electric conductance of the water-rock interaction system at high temperatures

    NASA Astrophysics Data System (ADS)

    Hu, S.; Zhang, R.; Zhang, X.

    2013-12-01

    Recently, we designed a new experimental apparatus, which was used to measure dissolution rates as water-rock interactions, and simultaneously in situ measure the electric conductance of the multi phase (rock - fluid) system. At first, a tubular reactor is put in horizontally. The rock sample was crushed and sieved to 20-40 mesh, and cleaned, then put in a titanium network bag inside of the vessel. The electric conductivity detectors were connected to the two ends of the vessel. Fluid inlet and outlet were also fabricated in the two ends of the vessel. And the furnace, temperature controller, liquid pump, back pressure regulator etc. are involved in the whole experimental system. High temperature (T) and pressure (P) electric conductivity measuring system consists of an electric conductivity detector (ECD limit.), which was reformed by us and connected to the vessel; and a transfer: T23-CDH-UM: 5.67(L)×3.50(W)×5.67(H) (inch).The distance between the two electrode of the sensor is 10cm. The electrode is 5cm of length and its diameter is 5/16 inch. Water-rock interaction experiments were performed using this apparatus. The volume inside of vessel is 10.81 ml, l= 170mm, d=4.5mm and 7.246g rock sample put in the vessel. The fluid velocity was changed from 1.5 to 3.5 ml/min, allowing the water through the sample. As in situ to measure the electric conductance of the rock-fluids in the vessel, continuously record the electric conductance, each record in 5 seconds. Water-basalt interaction experiments were carried out and in situ measured electric conductance at high T up to 450°C and at 22 to 36MPa. Basalt sample was collected from natural outcrop (volcanic area in Yangtze valley, China, which is K-rich trachy-basalt. Rock sample was crushed and sieved to 20-40 mesh, and cleaned. 8.0097g sample was put in the vessel (surface area: 1.37m2/g ). Experiments found dissolution rates (dis.r.) for different metals of the rock vary with T. Usually, dis.r., rSi increase with T

  5. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    NASA Astrophysics Data System (ADS)

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  6. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

    PubMed

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening. PMID:26429448

  7. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    SciTech Connect

    Kim, Jungdae; Nam, Hyoungdo; Schroeder, Allan; Shih, Chih-Kang; Qin, Shengyong; Kim, Sang-ui; Eom, Daejin

    2015-09-15

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  8. Validation of Land Surface Temperature products in arid climate regions with permanent in-situ measurements

    NASA Astrophysics Data System (ADS)

    Goettsche, F.; Olesen, F.; Trigo, I.; Hulley, G. C.

    2013-12-01

    Land Surface Temperature (LST) is operationally obtained from several space-borne sensors, e.g. from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard Meteosat Second Generation (MSG) by the Land Surface Analysis - Satellite Application Facility (LSA-SAF) and from the Moderate Resolution Imaging Spectroradiometer (MODIS) on EOS-Terra by the MODIS Land Team. The relative accuracy of LST products can be assessed by cross-validating different products. Alternatively, the so-called 'radiance based validation' can be used to compare satellite-retrieved LST with results from radiative transfer models: however, this requires precise a priori knowledge of land surface emissivity (LSE) and atmospheric conditions. Ultimately, in-situ measurements (';ground truth') are needed for validating satellite LST&E products. Therefore, the LST product derived by LSA-SAF is validated with independent in-situ measurements (';temperature based validation') at permanent validation stations located in different climate regions on the SEVIRI disk. In-situ validation is largely complicated by the spatial scale mismatch between satellite sensors and ground based sensors, i.e. areas observed by ground radiometers usually cover about 10 m2, whereas satellite measurements in the thermal infrared typically cover between 1 km2 and 100 km2. Furthermore, an accurate characterization of the surface is critical for all validation approaches, but particularly over arid regions, as shown by in-situ measurements revealing that LSE products can be wrong by more than 3% [1]. The permanent stations near Gobabeb (Namibia; hyper-arid desert climate) and Dahra (Senegal; hot-arid steppe-prairie climate) are two of KIT's four dedicated LST validation stations. Gobabeb station is located on vast and flat gravel plains (several 100 km2), which are mainly covered by coarse gravel, sand, and desiccated grass. The gravel plains are highly homogeneous in space and time, which makes them ideal for

  9. Temperature-dependent properties of silver-poly(methylmethacrylate) nanocomposites synthesized by in-situ technique

    PubMed Central

    2014-01-01

    Ag/PMMA nanocomposites were successfully synthesized by in-situ technique. Transmission electron microscopy (TEM) images show that the particles are spherical in shape and their sizes are dependent on temperature. The smallest particle achieved high stability as indicated from Zeta sizer analysis. The red shift of surface plasmon resonance (SPR) indicated the increases of particle sizes. X-ray diffraction (XRD) patterns exhibit a two-phase (crystalline and amorphous) structure of Ag/PMMA nanocomposites. The complexation of Ag/PMMA nanocomposites was confirmed using Raman spectroscopy. Fourier transform infrared spectroscopy spectra confirmed that the bonding was dominantly influenced by the PMMA and DMF solution. Finally, thermogravimetric analysis (TGA) results indicate that the total weight loss increases as the temperature increases. PMID:24450850

  10. Low-Temperature in Situ Growth of Graphene on Metallic Substrates and Its Application in Anticorrosion.

    PubMed

    Zhu, Minmin; Du, Zehui; Yin, Zongyou; Zhou, Wenwen; Liu, Zhengdong; Tsang, Siu Hon; Teo, Edwin Hang Tong

    2016-01-13

    Metal or alloy corrosion brings about huge economic cost annually, which is becoming one area of growing concern in various industries, being in bulk state or nanoscale range. Here, single layer or few layers of graphene are deposited on various metallic substrates directly at a low temperature down to 400 °C. These substrates can be varied from hundreds-micrometer bulk metallic or alloy foils to tens of nanometer nanofibers (NFs). Corrosion analysis reveals that both graphene-grown steel sheets and NFs have reduced the corrosion rate of up to ten times lower than that of their bare corresponding counterparts. Moreover, such low-temperature in situ growth of graphene demonstrates stable and long-lasting anticorrosion after long-term immersion. This new class of graphene coated nanomaterials shows high potentials in anticorrosion applications for submarines, oil tankers/pipelines, and ruggedized electronics. PMID:26683895

  11. Simple and compact optode for real-time in-situ temperature detection in very small samples

    PubMed Central

    Long, Feng; Shi, Hanchang

    2014-01-01

    Real-time in-situ temperature detection is essential in many applications. In this paper, a simple and robust optode, which uses Ruthenium (II) complex as a temperature indicator, has been developed for rapid and sensitive temperature detection in small volume samples (<5 μL). Transmission of excitation light and collection and transmission of fluorescence are performed by a homemade single-multi mode fiber coupler, which provides the entire system with a simple and robust structure. The photoluminescence intensity of Ruthenium (II) complex diminishes monotonically from 0°C to 80°C, and the response to temperature is rapid and completely reversible. When temperature is less than (or higher than) 50°C, a linear correlation exists between the fluorescence intensity and the temperature. Excellent agreement was also observed between the continuous and in situ measurements obtained by the presented optode and the discrete temperature values measured by a conventional thermometer. The proposed optode has high sensitivity, high photostability and chemical stability, a wide detection range, and thermal reversibility, and can be applied to real-time in-situ temperature detection of a very small volume biological, environmental, and chemical sample. PMID:24875420

  12. Simple and compact optode for real-time in-situ temperature detection in very small samples

    NASA Astrophysics Data System (ADS)

    Long, Feng; Shi, Hanchang

    2014-05-01

    Real-time in-situ temperature detection is essential in many applications. In this paper, a simple and robust optode, which uses Ruthenium (II) complex as a temperature indicator, has been developed for rapid and sensitive temperature detection in small volume samples (<5 μL). Transmission of excitation light and collection and transmission of fluorescence are performed by a homemade single-multi mode fiber coupler, which provides the entire system with a simple and robust structure. The photoluminescence intensity of Ruthenium (II) complex diminishes monotonically from 0°C to 80°C, and the response to temperature is rapid and completely reversible. When temperature is less than (or higher than) 50°C, a linear correlation exists between the fluorescence intensity and the temperature. Excellent agreement was also observed between the continuous and in situ measurements obtained by the presented optode and the discrete temperature values measured by a conventional thermometer. The proposed optode has high sensitivity, high photostability and chemical stability, a wide detection range, and thermal reversibility, and can be applied to real-time in-situ temperature detection of a very small volume biological, environmental, and chemical sample.

  13. In situ tryptophan-like fluorometers: assessing turbidity and temperature effects for freshwater applications.

    PubMed

    Khamis, K; Sorensen, J P R; Bradley, C; Hannah, D M; Lapworth, D J; Stevens, R

    2015-04-01

    Tryptophan-like fluorescence (TLF) is an indicator of human influence on water quality as TLF peaks are associated with the input of labile organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time measurement of TLF could be particularly useful for monitoring water quality at a higher temporal resolution than available hitherto. However, current understanding of TLF quenching/interference is limited for field deployable sensors. We present results from a rigorous test of two commercially available submersible tryptophan fluorometers (ex ∼ 285, em ∼ 350). Temperature quenching and turbidity interference were quantified in the laboratory and compensation algorithms developed. Field trials were then undertaken involving: (i) an extended deployment (28 days) in a small urban stream; and, (ii) depth profiling of an urban multi-level borehole. TLF was inversely related to water temperature (regression slope range: -1.57 to -2.50). Sediment particle size was identified as an important control on the turbidity specific TLF response, with signal amplification apparent <150 NTU for clay particles and <650 NTU for silt particles. Signal attenuation was only observed >200 NTU for clay particles. Compensation algorithms significantly improved agreement between in situ and laboratory readings for baseflow and storm conditions in the stream. For the groundwater trial, there was an excellent agreement between laboratory and raw in situ TLF; temperature compensation provided only a marginal improvement, and turbidity corrections were unnecessary. These findings highlight the potential utility of real time TLF monitoring for a range of environmental applications (e.g. tracing polluting sources and monitoring groundwater contamination). However, in situations where high/variable suspended sediment loads or rapid changes in temperature are anticipated concurrent monitoring of turbidity and temperature is required and site specific calibration is

  14. Low temperature barriers for use with in situ processes

    SciTech Connect

    Kim, Dong Sub; Vinegar, Harold J

    2009-06-16

    A method of forming and maintaining a low temperature zone around at least a portion of a subsurface treatment area is described. The method includes reducing a temperature of heat transfer fluid with a refrigeration system. The heat transfer fluid is circulated through freeze well canisters and placed in a formation around at least a portion of the subsurface treatment area. An initial temperature of the heat transfer fluid supplied to a first freeze well canister is in a range from about -35 .degree. C. to about -55 .degree. C. At least one of the well canisters includes carbon steel. The heat transfer fluid is returned to the refrigeration system.

  15. Bedrock temperature as a potential method for monitoring change in crustal stress: Theory, in situ measurement, and a case history

    NASA Astrophysics Data System (ADS)

    Chen, Shunyun; Liu, Peixun; Liu, Liqiang; Ma, Jin

    2016-06-01

    Experimental studies have confirmed that temperature is notably affected by rock deformation; therefore, change in crustal stress should be indicated by measurable changes in bedrock temperature. In this work, we investigated the possibility that the bedrock temperature might be used to explore the state of crustal stress. In situ measurement of bedrock temperature at three stations from 2011 to 2013 was used as the basis for the theoretical analysis of this approach. We began with theoretical analyses of temperature response to change in crustal stress, and of the effect of heat conduction. This allowed distinction between temperature changes produced by crustal stress (stress temperature) from temperature changes caused by conduction from the land surface (conduction temperature). Stress temperature has two properties (synchronous response and a high-frequency feature) that allow it to be distinguished from conduction temperature. The in situ measurements confirmed that apparently synchronous changes in the stress temperature of the bedrock occur and that there exist obvious short-term components of the in situ bedrock temperature, which agrees with theory. On 20 April 2013, an earthquake occurred 95 km away from the stations, fortuitously providing a case study by which to verify our method for obtaining the state of crustal stress using temperature. The results indicated that the level of local or regional seismic activity, representing the level of stress adjustment, largely accords with the stress temperature. This means that the bedrock temperature is a tool that might be applied to understand the state of stress during seismogenic tectonics. Therefore, it is possible to record changes in the state of crustal stress in a typical tectonic position by long-term observation of bedrock temperature. Hereby, the measurement of bedrock temperature has become a new tool for gaining insight into changes in the status of shallow crustal stress.

  16. In situ studies of microbial inactivation during high pressure processing

    NASA Astrophysics Data System (ADS)

    Maldonado, Jose Antonio; Schaffner, Donald W.; Cuitiño, Alberto M.; Karwe, Mukund V.

    2016-01-01

    High pressure processing (HPP) has been shown to reduce microbial concentration in foods. The mechanisms of microbial inactivation by HPP have been associated with damage to cell membranes. The real-time response of bacteria to HPP was measured to elucidate the mechanisms of inactivation, which can aid in designing more effective processes. Different pressure cycling conditions were used to expose Enterobacter aerogenes cells to HPP. Propidium iodide (PI) was used as a probe, which fluoresces after penetrating cells with damaged membranes and binding with nucleic acids. A HPP vessel with sapphire windows was used for measuring fluorescence in situ. Membrane damage was detected during pressurization and hold time, but not during depressurization. The drop in fluorescence was larger than expected after pressure cycles at higher pressure and longer times. This indicated possible reversible disassociation of ribosomes resulting in additional binding of PI to exposed RNA under pressure and its release after depressurization.

  17. Temperature-responsive compounds as in situ gelling biomedical materials.

    PubMed

    Moon, Hyo Jung; Ko, Du Young; Park, Min Hee; Joo, Min Kyung; Jeong, Byeongmoon

    2012-07-21

    Aqueous solutions that undergo sol-to-gel transition as the temperature increases have been extensively studied during the last decade. The material can be designed by controlling the hydrophilic and hydrophobic balance of the material. Basically, the molecular weight of the hydrophilic block and hydrophobic block of a compound should be fine-tuned from the synthetic point of view. In addition, stereochemistry, microsequence, topology, and nanostructures of the compound also affect the transition temperature, gel window, phase diagram, and modulus of the gel. From a practical point of view, biodegradability, biocompatibility, and interactions between the material and drug or cell should be considered in designing a thermogelling material. The interactions are particularly important in that they control drug release profile and initial burst release of the drug in the drug delivery system, and affect cell proliferation, differentiation, and biomarker expression in three-dimensional cell culture and tissue engineering application. This review provides an in-depth summary of the recent progress of thermogelling systems including polymers, low molecular compounds, and nanoemulsions. Their biomedical applications were also comparatively discussed. In addition, perspectives on future material design of a new thermogelling material and its application are suggested. PMID:22688789

  18. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    NASA Technical Reports Server (NTRS)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  19. Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond

    DOE PAGESBeta

    King, Jonathan P.; Jeong, Keunhong; Vassiliou, Christophoros C.; Shin, Chang S.; Page, Ralph H.; Avalos, Claudia E.; Wang, Hai-Jing; Pines, Alexander

    2015-12-07

    Low detection sensitivity stemming from the weak polarization of nuclear spins is a primary limitation of magnetic resonance spectroscopy and imaging. Methods have been developed to enhance nuclear spin polarization but they typically require high magnetic fields, cryogenic temperatures or sample transfer between magnets. Here we report bulk, room-temperature hyperpolarization of 13C nuclear spins observed via high-field magnetic resonance. The technique harnesses the high optically induced spin polarization of diamond nitrogen vacancy centres at room temperature in combination with dynamic nuclear polarization. We observe bulk nuclear spin polarization of 6%, an enhancement of ~170,000 over thermal equilibrium. The signal ofmore » the hyperpolarized spins was detected in situ with a standard nuclear magnetic resonance probe without the need for sample shuttling or precise crystal orientation. In conclusion, hyperpolarization via optical pumping/dynamic nuclear polarization should function at arbitrary magnetic fields enabling orders of magnitude sensitivity enhancement for nuclear magnetic resonance of solids and liquids under ambient conditions.« less

  20. Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond

    SciTech Connect

    King, Jonathan P.; Jeong, Keunhong; Vassiliou, Christophoros C.; Shin, Chang S.; Page, Ralph H.; Avalos, Claudia E.; Wang, Hai-Jing; Pines, Alexander

    2015-12-07

    Low detection sensitivity stemming from the weak polarization of nuclear spins is a primary limitation of magnetic resonance spectroscopy and imaging. Methods have been developed to enhance nuclear spin polarization but they typically require high magnetic fields, cryogenic temperatures or sample transfer between magnets. Here we report bulk, room-temperature hyperpolarization of 13C nuclear spins observed via high-field magnetic resonance. The technique harnesses the high optically induced spin polarization of diamond nitrogen vacancy centres at room temperature in combination with dynamic nuclear polarization. We observe bulk nuclear spin polarization of 6%, an enhancement of ~170,000 over thermal equilibrium. The signal of the hyperpolarized spins was detected in situ with a standard nuclear magnetic resonance probe without the need for sample shuttling or precise crystal orientation. In conclusion, hyperpolarization via optical pumping/dynamic nuclear polarization should function at arbitrary magnetic fields enabling orders of magnitude sensitivity enhancement for nuclear magnetic resonance of solids and liquids under ambient conditions.

  1. Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond

    PubMed Central

    King, Jonathan P.; Jeong, Keunhong; Vassiliou, Christophoros C.; Shin, Chang S.; Page, Ralph H.; Avalos, Claudia E.; Wang, Hai-Jing; Pines, Alexander

    2015-01-01

    Low detection sensitivity stemming from the weak polarization of nuclear spins is a primary limitation of magnetic resonance spectroscopy and imaging. Methods have been developed to enhance nuclear spin polarization but they typically require high magnetic fields, cryogenic temperatures or sample transfer between magnets. Here we report bulk, room-temperature hyperpolarization of 13C nuclear spins observed via high-field magnetic resonance. The technique harnesses the high optically induced spin polarization of diamond nitrogen vacancy centres at room temperature in combination with dynamic nuclear polarization. We observe bulk nuclear spin polarization of 6%, an enhancement of ∼170,000 over thermal equilibrium. The signal of the hyperpolarized spins was detected in situ with a standard nuclear magnetic resonance probe without the need for sample shuttling or precise crystal orientation. Hyperpolarization via optical pumping/dynamic nuclear polarization should function at arbitrary magnetic fields enabling orders of magnitude sensitivity enhancement for nuclear magnetic resonance of solids and liquids under ambient conditions. PMID:26639147

  2. A new method for in situ electron temperature determinations from plasma wave phenomena

    NASA Technical Reports Server (NTRS)

    Oya, H.; Benson, R. F.

    1972-01-01

    A discrepancy has been reported between the values of the electron temperature t sub e deduced from satellite electrostatic probe measurements and ground based radar backscatter measurements. This discrepancy (radar backscatter temperature less than the probe temperature) is not present when the probe experiment is flown on a rocket to lower altitudes but reappears when the rocket probe attains higher altitudes. There is a need for an independent radio wave method for making in-situ t sub e measurements in order to help resolve this problem. A new method of determining t sub e from the satellite resonant phenomena is presented. It is based on the splitting (observed at high latitudes) of the diffuse resonance which occurs at the frequency f sub d1 between f sub h and 2 f sub h. The advantage of this method over the other methods involving ionospheric resonances is the simplicity of the required calculations. There is, however, the limitation of plasma conditions where the f sub d1 resonance can be observed and the limitation to mid-to-high latitudes where the splitting is observed.

  3. High material efficiency MOVPE growth with in situ monitoring

    NASA Astrophysics Data System (ADS)

    Onitsuka, R.; Sugiyama, M.; Nakano, Y.

    2010-04-01

    The possibility of growing a GaAs single-junction solar cell structure with high growth rate and low partial pressure of tertiary-butylarsine (TBAs) has been explored in order to minimize the cost and material consumption in metal-organic vapor phase epitaxy (MOVPE). In situ surface reflectance anisotropy measurements suggested that we can grow reasonable quality GaAs layers at a growth rate of 3.3 μm/h and a V/III ratio of 2.5. Dark current-voltage characteristics of the pn junction that was grown at this condition yielded an ideality factor of 1.3, which was equivalent to the value obtained with a lower growth rate and higher V/III ratio, suggesting a possibility that we can grow GaAs with reasonable crystal quality at a high material efficiency. However, there seemed to exist spots of accumulated defects with a spacing of hundreds of micrometers at such a growth condition with a high material efficiency. If they are situated in the vicinity of the pn junction, the efficiency of the PV cell was significantly degraded, which suggests the necessity of tuning the growth conditions according to the impact of a layer on the electrical properties of a PV cell.

  4. In Situ Contaminate Stabilization within a Complex and Highly Heterogeneous Fractured Media

    NASA Astrophysics Data System (ADS)

    Scott, C. L.; Heath, G. L.; Baker, K. E.; Schafer, A. L.

    2006-12-01

    Radionuclides that are adsorbed in vadose zone soils are a contamination source of subsurface waters on DOE sites. Source contamination typically was a localized leak in surface or near-surface process equipment. Immobilizing or sequestering such contaminants in situ is a preferred remediation technique for economic and technical reasons. In situ contaminate stabilization can be challenging when the subsurface geology is complex and highly heterogeneous. The contaminate stabilization is accomplished by introducing an amendment, water-soluble polymer, into contact with the contaminated porous medium. This paper will present results from a series of laboratory experiments preformed in layered heterogeneous tanks that were monitored using 4 D electrical resistivity, temperature, conductivity of incoming and outgoing tank fluids. The experiments were designed to show that monitoring as well as sequestering radionuclides (Sr90) in perched groundwater within fractured media was possible.

  5. Stream temperature estimated in situ from thermal-infrared images: best estimate and uncertainty

    NASA Astrophysics Data System (ADS)

    Iezzi, F.; Todisco, M. T.

    2015-11-01

    The paper aims to show a technique to estimate in situ the stream temperature from thermal-infrared images deepening its best estimate and uncertainty. Stream temperature is an important indicator of water quality and nowadays its assessment is important particularly for thermal pollution monitoring in water bodies. Stream temperature changes are especially due to the anthropogenic heat input from urban wastewater and from water used as a coolant by power plants and industrial manufacturers. The stream temperatures assessment using ordinary techniques (e.g. appropriate thermometers) is limited by sparse sampling in space due to a spatial discretization necessarily punctual. Latest and most advanced techniques assess the stream temperature using thermal-infrared remote sensing based on thermal imagers placed usually on aircrafts or using satellite images. These techniques assess only the surface water temperature and they are suitable to detect the temperature of vast water bodies but do not allow a detailed and precise surface water temperature assessment in limited areas of the water body. The technique shown in this research is based on the assessment of thermal-infrared images obtained in situ via portable thermal imager. As in all thermographic techniques, also in this technique, it is possible to estimate only the surface water temperature. A stream with the presence of a discharge of urban wastewater is proposed as case study to validate the technique and to show its application limits. Since the technique analyzes limited areas in extension of the water body, it allows a detailed and precise assessment of the water temperature. In general, the punctual and average stream temperatures are respectively uncorrected and corrected. An appropriate statistical method that minimizes the errors in the average stream temperature is proposed. The correct measurement of this temperature through the assessment of thermal- infrared images obtained in situ via portable

  6. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    NASA Astrophysics Data System (ADS)

    Wang, Xuebing; Chen, Ting; Qi, Xintong; Zou, Yongtao; Kung, Jennifer; Yu, Tony; Wang, Yanbin; Liebermann, Robert C.; Li, Baosheng

    2015-08-01

    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 Al2O3 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 Al2O3 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.

  7. 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.

  8. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  9. In situ monitoring of internal surface temperature of the historic building envelope

    NASA Astrophysics Data System (ADS)

    Labovská, Veronika; Katunský, Dušan

    2016-06-01

    Historical building envelope is characterized by a large accumulation that impact is mainly by changing the inner surface temperature over time. The minimum value of the inner surface temperature is set Code requirements. In the case of thermal technology assessment of building envelope contemplates a steady state external temperature and internal environment, thereby neglecting the heat accumulation capacity of building envelopes. Monitoring surface temperature in real terms in situ shows the real behavior of the building envelope close to reality. The recorded data can be used to create a numerical model for the simulation.

  10. In-situ high-pressure transmission electron microscopy of minerals

    NASA Astrophysics Data System (ADS)

    Wu, J.; Buseck, P. R.

    2010-12-01

    We show that high-resolution studies are possible at high pressure and temperature within a transmission electron microscope (TEM). To achieve this goal, which avoids the crystallographic and chemical changes that can occur upon quenching, we use the unusual structural properties of carbon nanotubes (CNTs) and fullerenes. These carbon materials, which are used as sample containers, contract under radiation by energetic electrons at elevated temperatures in a TEM. The result is compression of materials that have been encapsulated within these containers. We estimated pressures greater than 20 GPa from the Fourier transforms of high-resolution images of oxide particles such as ZnO and Sm2O3 under compression within CNTs. Using an arc-discharge technique, we recently also loaded olivine into fullerenes. Such ability to compress and then examine minerals in situ at high resolution opens up new possibilities for the high-pressure research of minerals.

  11. Polarimetric fiber grating biosensor for in-situ high-sensitive intracellular density measurement

    NASA Astrophysics Data System (ADS)

    Guo, Tuan; Liu, Fu; Liu, Yu; Chen, Nan-Kuang; Guan, Bai-Ou; Albert, Jacques

    2014-05-01

    High sensitivity biological sample measurements have been achieved by using a 12o tilted fiber Bragg grating (TFBG). Human acute leukemia cells with different intracellular densities and refractive index (RI) ranging from 1.3342 to 1.3344 were clearly discriminated in-situ by using the differential transmission spectrum between two orthogonal polarizations for the last guided mode resonance before "cut-off", with an amplitude variation sensitivity of 1.8×104 dB/RIU and a limit of detection of 2×10-5 RIU. The technique is inherently temperature-insensitive.

  12. Structure determination of an integral membrane protein at room temperature from crystals in situ

    SciTech Connect

    Axford, Danny; Foadi, James; Hu, Nien-Jen; Choudhury, Hassanul Ghani; Iwata, So; Beis, Konstantinos; Evans, Gwyndaf; Alguel, Yilmaz

    2015-05-14

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines.

  13. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  14. In situ high-temperature high-pressure Raman spectroscopy on single-crystal relaxor ferroelectrics PbSc1/2Ta1/2O3 and PbSc1/2Nb1/2O3

    NASA Astrophysics Data System (ADS)

    Waeselmann, N.; Mihailova, B.; Gospodinov, M.; Bismayer, U.

    2013-04-01

    The effect of temperature on the pressure-induced structural changes in perovskite-type (ABO3) relaxor ferroelectrics is studied by in situ high-temperature high-pressure Raman spectroscopy on single crystals of PbSc1/2Ta1/2O3 (PST) and PbSc1/2Nb1/2O3 (PSN), which allowed us to elucidate the interplay between the polar and antiferrodistortive order coexisting on the mesoscopic scale at ambient conditions. High-pressure experiments were carried out at elevated temperatures below and above the characteristic intermediate temperature T*. The results were compared with those obtained at room temperature, which for PST is just above the paraelectric-ferroelectric phase transition TC, whereas for PSN is below TC. It is shown that the first critical pressure pc1, at which a transition from a relaxor to a non-polar rhombohedral state with antiphase octahedral tilt ordering occurs, decreases at elevated temperatures due to the weakening of the polar coupling, which in turn facilitates the evolution of the preexisting medium-range antiferrodistortive order into a long-range order. The critical pressure pc2 of the second phase transition, involving a change in the type of the antiferrodistortive order, is not affected by temperature, i.e. it is independent of the state of polar coupling and is mainly related to the initial correlation length of antiferrodistortive order. The strong influence of temperature on pc1, which occurs only when the mesoscopic polar order is suppressed, emphasizes the importance of coexisting ferroelectric and antiferrodistortive coupling for the occurrence of the relaxor states.

  15. Comparison of MTI Satellite-Derived Surface Water Temperatures and In-Situ Measurements

    SciTech Connect

    Kurzeja, R.

    2001-07-26

    Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1 percent of the calculated values at the Pacific Ocean site but were 1-2 percent different over the mid-latitude lake.

  16. Comparison of MTI satellite-derived surface water temperatures and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Kurzeja, Robert J.; Pendergast, Malcolm M.; Villa-Aleman, Eliel; Garrett, Alfred J.

    2002-01-01

    Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1% of the calculated values at the Pacific Ocean site but were 1-2% different over the mid-latitude lake.

  17. In-situ temperature calibration procedure for temperature and strain fibre Bragg grating sensors for monitoring pre-stressing strands

    NASA Astrophysics Data System (ADS)

    Mckeeman, I.; Fusiek, G.; Perry, M.; Niewczas, P.; Johnston, M.

    2015-09-01

    In this work, we demonstrate active and passive methods for in-situ temperature calibration of fibre Bragg grating strain and temperature sensors. The method is suitable for characterising sensors which are already attached to the steel reinforcements of civil structures. The proposed method, which involves the use of active induction heating or passive room temperature fluctuations, can be implemented using portable equipment, is time efficient, and can be used to calibrate attached sensors on-site, rather than in lab conditions. Preliminary results of the induction heating calibration show good agreement with pre-calibrated temperature sensors. In-situ calibration of fibre strain sensors, attached to a prestressing strand is also successfully carried out.

  18. Temperature control in thermal microactuators with applications to in-situ nanomechanical testing

    NASA Astrophysics Data System (ADS)

    Qin, Qingquan; Zhu, Yong

    2013-01-01

    Thermal microactuators are used in many micro/nano-technologies. To circumvent undesired heating of the end effector, heat sink beams are co-fabricated with the thermal actuator and connected to the substrate. This paper reports a combined experimental and modeling study on the effect of such heat sink beams. Temperature distribution is measured and simulated using Raman scattering and multiphysics finite element method, respectively. Our results show that heat sink beams are effective in controlling the temperature of the thermal actuator. Insights on how to achieve both low temperature and large actuator displacement for in-situ mechanical testing of nanoscale specimens are provided.

  19. Development of an in situ temperature stage for synchrotron X-ray spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Chakraborty, R.; Serdy, J.; West, B.; Stuckelberger, M.; Lai, B.; Maser, J.; Bertoni, M. I.; Culpepper, M. L.; Buonassisi, T.

    2015-11-01

    In situ characterization of micro- and nanoscale defects in polycrystalline thin-film materials is required to elucidate the physics governing defect formation and evolution during photovoltaic device fabrication and operation. X-ray fluorescence spectromicroscopy is particularly well-suited to study defects in compound semiconductors, as it has a large information depth appropriate to study thick and complex materials, is sensitive to trace amounts of atomic species, and provides quantitative elemental information, non-destructively. Current in situ methods using this technique typically require extensive sample preparation. In this work, we design and build an in situ temperature stage to study defect kinetics in thin-film solar cells under actual processing conditions, requiring minimal sample preparation. Careful selection of construction materials also enables controlled non-oxidizing atmospheres inside the sample chamber such as H2Se and H2S. Temperature ramp rates of up to 300 °C/min are achieved, with a maximum sample temperature of 600 °C. As a case study, we use the stage for synchrotron X-ray fluorescence spectromicroscopy of CuInxGa1-xSe2 (CIGS) thin-films and demonstrate predictable sample thermal drift for temperatures 25-400 °C, allowing features on the order of the resolution of the measurement technique (125 nm) to be tracked while heating. The stage enables previously unattainable in situ studies of nanoscale defect kinetics under industrially relevant processing conditions, allowing a deeper understanding of the relationship between material processing parameters, materials properties, and device performance.

  20. Development of an in situ temperature stage for synchrotron X-ray spectromicroscopy

    SciTech Connect

    Chakraborty, R. E-mail: buonassisi@mit.edu; Serdy, J.; Culpepper, M. L.; Buonassisi, T. E-mail: buonassisi@mit.edu; West, B.; Stuckelberger, M.; Bertoni, M. I.; Lai, B.; Maser, J.

    2015-11-15

    In situ characterization of micro- and nanoscale defects in polycrystalline thin-film materials is required to elucidate the physics governing defect formation and evolution during photovoltaic device fabrication and operation. X-ray fluorescence spectromicroscopy is particularly well-suited to study defects in compound semiconductors, as it has a large information depth appropriate to study thick and complex materials, is sensitive to trace amounts of atomic species, and provides quantitative elemental information, non-destructively. Current in situ methods using this technique typically require extensive sample preparation. In this work, we design and build an in situ temperature stage to study defect kinetics in thin-film solar cells under actual processing conditions, requiring minimal sample preparation. Careful selection of construction materials also enables controlled non-oxidizing atmospheres inside the sample chamber such as H{sub 2}Se and H{sub 2}S. Temperature ramp rates of up to 300 °C/min are achieved, with a maximum sample temperature of 600 °C. As a case study, we use the stage for synchrotron X-ray fluorescence spectromicroscopy of CuIn{sub x}Ga{sub 1−x}Se{sub 2} (CIGS) thin-films and demonstrate predictable sample thermal drift for temperatures 25–400 °C, allowing features on the order of the resolution of the measurement technique (125 nm) to be tracked while heating. The stage enables previously unattainable in situ studies of nanoscale defect kinetics under industrially relevant processing conditions, allowing a deeper understanding of the relationship between material processing parameters, materials properties, and device performance.

  1. In situ LIF temperature measurements in aqueous ammonium chloride solution during uni-directional solidification

    NASA Astrophysics Data System (ADS)

    Shafii, M. Behshad; Lum, Chee L.; Koochesfahani, Manoochehr M.

    2010-04-01

    We present in situ whole-field measurements of the temperature field using laser-induced fluorescence in a study of bottom-chilled uni-directional solidification of aqueous ammonium chloride. We utilize a two-color, two-dye, ratiometric approach to address the significant spatial and temporal variations of laser sheet intensity field due to refractive index variations caused by the evolving concentration and temperature fields. In our work we take advantage of two temperature sensitive fluorescent dyes with opposite temperature sensitivities in order to increase the overall sensitivity and temperature resolution of the measurements. The resulting temperature sensitivity (about 4% K-1) is more than a factor of two higher than the original work of Sakakibara and Adrian (Exp Fluids 26:7-15, 1999) with a sensitivity 1.7% K-1. In situ measurements of the temperature field during solidification are presented, along with temperature characteristics of some of the complex flow features, such as plumes and fingers.

  2. High voltage-power frequency electrical heating in-situ conversion technology of oil shale

    NASA Astrophysics Data System (ADS)

    Sun, Youhong; Yang, Yang; Lopatin, Vladimir; Guo, Wei; Liu, Baochang; Yu, Ping; Gao, Ke; Ma, Yinlong

    2014-05-01

    With the depletion of conventional energy sources,oil shale has got much attention as a new type of energy resource,which is rich and widespread in the world.The conventional utilization of oil shale is mainly focused on resorting to produce shale oil and fuel gas with low extraction efficiency about one in a million due to many shortcomings and limitations.And the in-situ conversion of oil shale,more environmentally friendly,is still in the experimental stage.High voltage-power frequency electrical heating in-situ conversion of oil shale is a new type of in-situ pyrolysis technology.The main equipment includes a high voltage-power frequency generator and interior reactor. The high voltage-power frequency generator can provide a voltage between 220-8000 V which can be adjusted in real time according to the actual situation.Firstly,high voltage is used to breakdown the oil shale to form a dendritic crack between two electrodes providing a conductive channel inside the oil shale rock.And then the power frequency(220V) is used to generate the electric current for heating the internal surface of conductive channel,so that the energy can be transmitted to the surrounding oil shale.When the temperature reaches 350 degree,the oil shale begins to pyrolysis.In addition,the temperature in the conductive channel can be extremely high with high voltage,which makes the internal surface of conductive channel graphitization and improves its heat conduction performance.This technology can successfully make the oil shale pyrolysis, based on a lot of lab experiments,and also produce the combustible shale oil and fuel gas.Compared to other in-situ conversion technology,this method has the following advantages: high speed of heating oil shale,the equipment underground is simple,and easy to operate;it can proceed without the limitation of shale thickness, and can be used especially in the thin oil shale reservoir;the heating channel is parallel to the oil shale layers,which has more

  3. High-resistive layers obtained through periodic growth and in situ annealing of InGaN by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; Ma, Ping; Liu, Boting; Wu, Dongxue; Huang, Yuliang; Wang, Junxi; Li, Jinmin

    2016-06-01

    High-resistive layers were obtained by periodic growth and in situ annealing of InGaN. The effect of the annealing temperature of InGaN on the indium content and the material sheet resistive was investigated. The indium content decreased as the increase of in situ annealing temperature. Additionally, the material sheet resistance increased with the increase of the in situ annealing temperature for the annealed samples and reached 2 × 1010Ω/sq in the light and 2 × 1011Ω/sq in the dark when the in situ annealing temperature reached 970∘C. The acquirement of high-resistive layers is attributed to the generation of indium vacancy-related defects. Introducing indium vacancy-related defects to compensate background carriers can be an effective method to grow high-resistance material.

  4. Rapid thermal processing of high-efficiency silicon solar cells with controlled in-situ annealing

    SciTech Connect

    Doshi, P.; Rohatgi, A.; Ropp, M.; Chen, Z.; Ruby, D.; Meier, D.L.

    1995-01-01

    Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable minority-carrier lifetime and diffusion profiles for high-efficiency cells. The cooling rate associated with the in-situ anneal can improve the lifetime and lower the reverse saturation current density (J{sub 0}), however, this effect is material and base resistivity specific. PECVD antireflection (AR) coatings provided low reflectance and efficient front surface and bulk defect passivation. Conventional cells fabricated on FZ silicon by furnace diffusions and oxidations gave an efficiency of 18.8% due to greater short wavelength response and lower J{sub 0}.

  5. Seasonal variation in phosphorus concentration-discharge hysteresis inferred from high-frequency in situ monitoring

    NASA Astrophysics Data System (ADS)

    Bieroza, M. Z.; Heathwaite, A. L.

    2015-05-01

    High-resolution in situ total phosphorus (TP), total reactive phosphorus (TRP) and turbidity (TURB) time series are presented for a groundwater-dominated agricultural catchment. Meta-analysis of concentration-discharge (c-q) intra-storm signatures for 61 storm events revealed dominant hysteretic patterns with similar frequency of anti-clockwise and clockwise responses; different determinands (TP, TRP, TURB) behaved similarly. We found that the c-q loop direction is controlled by seasonally variable flow discharge and temperature whereas the magnitude is controlled by antecedent rainfall. Anti-clockwise storm events showed lower flow discharge and higher temperature compared to clockwise events. Hydrological controls were more important for clockwise events and TP and TURB responses, whereas in-stream biogeochemical controls were important for anti-clockwise storm events and TRP responses. Based on the best predictors of the direction of the hysteresis loops, we calibrated and validated a simple fuzzy logic inference model (FIS) to determine likely direction of the c-q responses. We show that seasonal and inter-storm succession in clockwise and anti-clockwise responses corroborates the transition in P transport from a chemostatic to an episodic regime. Our work delivers new insights for the evidence base on the complexity of phosphorus dynamics. We show the critical value of high-frequency in situ observations in advancing understanding of freshwater biogeochemical processes.

  6. In Situ Determination of BCC-, FCC- and HPC-Iron Textures at Simultaneous High- Pressure and -Temperature by Means of the Resistive Heated Radial Diffraction Diamond Anvil Cell (RH-RD-DAC): Implications for the iron core.

    NASA Astrophysics Data System (ADS)

    Liermann, H.; Merkel, S.; Miyagi, L.; Wenk, H.; Shen, G.; Cynn, H.; Evans, W. J.

    2008-12-01

    Radial diffraction in the diamond anvil cell (DAC) has long been used to determine the stress state of materials under non-hydrostatic compression. This technique is also a major tool to investigate textures and infer deformation mechanisms in the earth mantle and core. However, most of these experiments have been conducted at ambient temperatures and therefore the results of these measurements may be difficult to extrapolate to the deep Earth. Here, we present texture data collected at HPCAT sector 16 BMD of the Advanced Photon Source during the plastic deformation of BCC-, FCC- and HPC-iron at simultaneous high-pressure and temperature in the new Resistive Heated Radial Diffraction Diamond Anvil Cell (RH-RD-DAC). Initial results from Rietveld refinements in MAUD indicate that BCC- iron develops a mixed {100} and {111} texture that remains active during heating. Latter is compatible with previous observations on BCC-iron and interpreted as slip along {110}<111>. Texture obtained after formation of FCC-iron at simultaneous high- pressure and temperatures show a pronounced maximum at {110} with minima at {100} and {111}. This texture is typical for FCC metals in compression with slip on {111}<110>. Processing of the HCP-iron textures at high-pressure and -temperature are under way. We will discuss the implications that the experimental results have for the deformation mechanisms of iron at pressure temperature conditions of the inner core.

  7. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

    SciTech Connect

    Rutqvist, J.

    2014-09-19

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on local in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.

  8. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

    DOE PAGESBeta

    Rutqvist, J.

    2014-09-19

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

  9. Low-temperature plasticity of olivine revisited with in situ TEM nanomechanical testing

    PubMed Central

    Idrissi, Hosni; Bollinger, Caroline; Boioli, Francesca; Schryvers, Dominique; Cordier, Patrick

    2016-01-01

    The rheology of the lithospheric mantle is fundamental to understanding how mantle convection couples with plate tectonics. However, olivine rheology at lithospheric conditions is still poorly understood because experiments are difficult in this temperature range where rocks and mineral become very brittle. We combine techniques of quantitative in situ tensile testing in a transmission electron microscope and numerical modeling of dislocation dynamics to constrain the low-temperature rheology of olivine. We find that the intrinsic ductility of olivine at low temperature is significantly lower than previously reported values, which were obtained under strain-hardened conditions. Using this method, we can anchor rheological laws determined at higher temperature and can provide a better constraint on intermediate temperatures relevant for the lithosphere. More generally, we demonstrate the possibility of characterizing the mechanical properties of specimens, which can be available in the form of submillimeter-sized particles only. PMID:26998522

  10. Low-temperature plasticity of olivine revisited with in situ TEM nanomechanical testing.

    PubMed

    Idrissi, Hosni; Bollinger, Caroline; Boioli, Francesca; Schryvers, Dominique; Cordier, Patrick

    2016-03-01

    The rheology of the lithospheric mantle is fundamental to understanding how mantle convection couples with plate tectonics. However, olivine rheology at lithospheric conditions is still poorly understood because experiments are difficult in this temperature range where rocks and mineral become very brittle. We combine techniques of quantitative in situ tensile testing in a transmission electron microscope and numerical modeling of dislocation dynamics to constrain the low-temperature rheology of olivine. We find that the intrinsic ductility of olivine at low temperature is significantly lower than previously reported values, which were obtained under strain-hardened conditions. Using this method, we can anchor rheological laws determined at higher temperature and can provide a better constraint on intermediate temperatures relevant for the lithosphere. More generally, we demonstrate the possibility of characterizing the mechanical properties of specimens, which can be available in the form of submillimeter-sized particles only. PMID:26998522

  11. Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

    NASA Astrophysics Data System (ADS)

    Canion, A.; Kostka, J. E.; Gihring, T. M.; Huettel, M.; van Beusekom, J. E. E.; Gao, H.; Lavik, G.; Kuypers, M. M. M.

    2013-09-01

    Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from -5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m-2 d-1. For the majority of sites studied, N2 removal was 2 to 7 times more rapid under advective flow conditions. Anammox comprised 6 to 14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of -1 to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. To our knowledge, we provide the first rates of denitrification and anammox from permeable sediments of a polar permanently cold ecosystem. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent

  12. Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

    NASA Astrophysics Data System (ADS)

    Canion, A.; Kostka, J. E.; Gihring, T. M.; Huettel, M.; van Beusekom, J. E. E.; Gao, H.; Lavik, G.; Kuypers, M. M. M.

    2014-01-01

    Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from -5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m-2 d-1. For the majority of sites studied, N2 removal was 2-7 times more rapid under simulated advective flow conditions. Anammox comprised 6-14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of -1 °C to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure.

  13. In situ investigation of Geobacillus stearothermophilus spore germination and inactivation mechanisms under moderate high pressure.

    PubMed

    Georget, Erika; Kapoor, Shobhna; Winter, Roland; Reineke, Kai; Song, Youye; Callanan, Michael; Ananta, Edwin; Heinz, Volker; Mathys, Alexander

    2014-08-01

    Bacterial spores are a major concern for food safety due to their high resistance to conventional preservation hurdles. Innovative hurdles can trigger bacterial spore germination or inactivate them. In this work, Geobacillus stearothermophilus spore high pressure (HP) germination and inactivation mechanisms were investigated by in situ infrared spectroscopy (FT-IR) and fluorometry. G. stearothermophilus spores' inner membrane (IM) was stained with Laurdan fluorescent dye. Time-dependent FT-IR and fluorescence spectra were recorded in situ under pressure at different temperatures. The Laurdan spectrum is affected by the lipid packing and level of hydration, and provided information on the IM state through the Laurdan generalized polarization. Changes in the -CH2 and -CH3 asymmetric stretching bands, characteristic of lipids, and in the amide I' band region, characteristic of proteins' secondary structure elements, enabled evaluation of the impact of HP on endospores lipid and protein structures. These studies were complemented by ex situ analyses (plate counts and microscopy). The methods applied showed high potential to identify germination mechanisms, particularly associated to the IM. Germination up to 3 log10 was achieved at 200 MPa and 55 °C. A molecular-level understanding of these mechanisms is important for the development and validation of multi-hurdle approaches to achieve commercial sterility. PMID:24750808

  14. Temperature and layer thickness dependent in situ investigations on epindolidione organic thin-film transistors

    PubMed Central

    Lassnig, R.; Striedinger, B.; Jones, A.O.F.; Scherwitzl, B.; Fian, A.; Głowacl, E.D.; Stadlober, B.; Winkler, A.

    2016-01-01

    We report on in situ performance evaluations as a function of layer thickness and substrate temperature for bottom-gate, bottom-gold contact epindolidione organic thin-film transistors on various gate dielectrics. Experiments were carried out under ultra-high vacuum conditions, enabling quasi-simultaneous electrical and surface analysis. Auger electron spectroscopy and thermal desorption spectroscopy (TDS) were applied to characterize the quality of the substrate surface and the thermal stability of the organic films. Ex situ atomic force microscopy (AFM) was used to gain additional information on the layer formation and surface morphology of the hydrogen-bonded organic pigment. The examined gate dielectrics included SiO2, in its untreated and sputtered forms, as well as the spin-coated organic capping layers poly(vinyl-cinnamate) (PVCi) and poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE, from the class of polynorbornenes). TDS and AFM revealed Volmer-Weber island growth dominated film formation with no evidence of a subjacent wetting layer. This growth mode is responsible for the comparably high coverage required for transistor behavior at 90–95% of a monolayer composed of standing molecules. Surface sputtering and an increased sample temperature during epindolidione deposition augmented the surface diffusion of adsorbing molecules and therefore led to a lower number of better-ordered islands. Consequently, while the onset of charge transport was delayed, higher saturation mobility was obtained. The highest, bottom-contact configuration, mobilities of approximately 2.5 × 10−3cm2/Vs were found for high coverages (50 nm) on sputtered samples. The coverage dependence of the mobility showed very different characteristics for the different gate dielectrics, while the change of the threshold voltage with coverage was approximately the same for all systems. An apparent decrease of the mobility with increasing coverage on the

  15. High pressure optical cell for synthesis and in situ Raman spectroscopy of hydrogen clathrate hydrates

    NASA Astrophysics Data System (ADS)

    Celli, Milva; Zoppi, Marco; Zaghloul, Mohamed A. S.; Ulivi, Lorenzo

    2012-11-01

    We report the design, realization, and test of a high-pressure optical cell that we have used to measure the Raman spectra of hydrogen clathrate hydrates, synthesized in situ by the application of 200-300 MPa of gas pressure on solid water. The optical apparatus is mounted on a cryogenic system so to allow measurements and sample treatment at any temperature between 300 and 20 K. A capillary pipe is connected to the inside of the cell to allow the gas flow into and out of the cell, and to regulate the internal pressure at any value from 0 to 300 MPa. In the experimental test described in this paper, the cell has been partly filled, at room temperature, with a small amount of water, then frozen at 263 K before injecting hydrogen gas, at pressure of 150 MPa, into the cell. This procedure has permitted to study hydrogen clathrate formation, by measuring Raman spectra as a function of time.

  16. The first in situ electron temperature and density measurements of the Martian nightside ionosphere

    NASA Astrophysics Data System (ADS)

    Fowler, C. M.; Andersson, L.; Ergun, R. E.; Morooka, M.; Delory, G.; Andrews, D. J.; Lillis, Robert J.; McEnulty, T.; Weber, T. D.; Chamandy, T. M.; Eriksson, A. I.; Mitchell, D. L.; Mazelle, C.; Jakosky, B. M.

    2015-11-01

    The first in situ nightside electron density and temperature profiles at Mars are presented as functions of altitude and local time (LT) from the Langmuir Probe and Waves (LPW) instrument on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission spacecraft. LPW is able to measure densities as low as ˜100 cm-3, a factor of up to 10 or greater improvement over previous measurements. Above 200 km, near-vertical density profiles of a few hundred cubic centimeters were observed for almost all nightside LT, with the lowest densities and highest temperatures observed postmidnight. Density peaks of a few thousand cubic centimeters were observed below 200 km at all nightside LT. The lowest temperatures were observed below 180 km and approach the neutral atmospheric temperature. One-dimensional modeling demonstrates that precipitating electrons were able to sustain the observed nightside ionospheric densities below 200 km.

  17. Simultaneous in-situ measurements of neutral temperature and oxygen in the mesosphere during the WADIS sounding rocket project

    NASA Astrophysics Data System (ADS)

    Strelnikov, Boris; Lübken, Franz-Josef; Rapp, Markus; Grygalashvyly, Mykhaylo; Löhle, Stefan; Eberhart, Martin; Fasoulas, Stefanos; Hedin, Jonas; Gumbel, Jörg; Khaplanov, Mikhail; Stegman, Jacek; Friedrich, Martin

    2016-04-01

    The WADIS project (Wave propagation and dissipation in the middle atmosphere: energy budget and distribution of trace constituents) aimed at studying waves, their dissipation, and effects on trace constituents. The project comprised two sounding rocket campaigns conducted at the Andøya Space Center (69 °N, 16 °E). One sounding rocket was launched in summer 2013 and one in winter 2015. In-situ measurements delivered high resolution altitude-profiles of neutral temperature and density, as well as plasma and oxygen densities. Atomic oxygen was measured by two different techniques. Airglow photometers operated by MISU measured emissions from excited molecular oxygen at 1.27 um (daytime summer launch) and 762 nm (night-time winter launch), both of which can be used to infer altitude profiles of atomic oxygen. This is a well-proven technique and has been applied to sounding rocket and satellite measurements in the past. Solid electrolyte sensors (FIPEX) operated by IRS is a new technique for sounding rockets, which yielded atomic oxygen density profiles with a height resolution better than 10 m. The neutral air density and temperature was measured by the CONE instrument also with very heigh altitude resolution and precision. All these instruments were mounted on the same deck of the sounding rocket and, therefore delivered real common volume measurements. In this paper we present simultaneous in-situ temperature and oxygen density measurements and discuss how variability of these quantities may influence temperature derivations from OH airglow observations at mesopause heights.

  18. In situ growth of carbon nanotube wrapped Si composites as anodes for high performance lithium ion batteries.

    PubMed

    Zhou, Jianbin; Lan, Yang; Zhang, Kailong; Xia, Guoliang; Du, Jin; Zhu, Yongchun; Qian, Yitai

    2016-03-01

    The composites of carbon nanotube wrapped Si particles (CNTWS) were synthesized in situ by using the catalytic chemical vapor deposition (CCVD) method. In this process, carbon nanotubes were produced in situ to wrap Si by the catalysis action of nascent Cu* under an acetylene atmosphere at a relatively low temperature of 400 °C, in which nascent Cu* was created by the reaction between Si particles and CuCl synchronously. The weight ratio of Si/C in CNTWS is 0.76/0.24. As anode materials for lithium ion batteries, the CNTWS composites exhibit a reversible discharge capacity of 1031.1 mA h g(-1) at 1.8 A g(-1) after 500 cycles, and 868.2 mA h g(-1) at 10.0 A g(-1). The high electrochemical performance of CNTWS composites is associated with the in situ formed carbon nanotubes. PMID:26875542

  19. In situ growth of carbon nanotube wrapped Si composites as anodes for high performance lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zhou, Jianbin; Lan, Yang; Zhang, Kailong; Xia, Guoliang; Du, Jin; Zhu, Yongchun; Qian, Yitai

    2016-02-01

    The composites of carbon nanotube wrapped Si particles (CNTWS) were synthesized in situ by using the catalytic chemical vapor deposition (CCVD) method. In this process, carbon nanotubes were produced in situ to wrap Si by the catalysis action of nascent Cu* under an acetylene atmosphere at a relatively low temperature of 400 °C, in which nascent Cu* was created by the reaction between Si particles and CuCl synchronously. The weight ratio of Si/C in CNTWS is 0.76/0.24. As anode materials for lithium ion batteries, the CNTWS composites exhibit a reversible discharge capacity of 1031.1 mA h g-1 at 1.8 A g-1 after 500 cycles, and 868.2 mA h g-1 at 10.0 A g-1. The high electrochemical performance of CNTWS composites is associated with the in situ formed carbon nanotubes.The composites of carbon nanotube wrapped Si particles (CNTWS) were synthesized in situ by using the catalytic chemical vapor deposition (CCVD) method. In this process, carbon nanotubes were produced in situ to wrap Si by the catalysis action of nascent Cu* under an acetylene atmosphere at a relatively low temperature of 400 °C, in which nascent Cu* was created by the reaction between Si particles and CuCl synchronously. The weight ratio of Si/C in CNTWS is 0.76/0.24. As anode materials for lithium ion batteries, the CNTWS composites exhibit a reversible discharge capacity of 1031.1 mA h g-1 at 1.8 A g-1 after 500 cycles, and 868.2 mA h g-1 at 10.0 A g-1. The high electrochemical performance of CNTWS composites is associated with the in situ formed carbon nanotubes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08961a

  20. Kinetics of Methane Hydrate Decomposition Studied via in Situ Low Temperature X-ray Powder Diffraction

    SciTech Connect

    Everett, Susan M; Rawn, Claudia J; Keffer, David J.; Mull, Derek L; Payzant, E Andrew; Phelps, Tommy Joe

    2013-01-01

    Gas hydrates are known to have a slowed decomposition rate at ambient pressure and temperatures below the melting point of ice termed self-preservation or anomalous preservation. As hydrate exothermically decomposes, gas is released and water of the clathrate cages transforms into ice. Two regions of slowed decomposition for methane hydrate, 180 200 K and 230 260 K, were observed, and the kinetics were studied by in situ low temperature x-ray powder diffraction. The kinetic constants for ice formation from methane hydrate were determined by the Avrami model within each region and activation energies, Ea, were determined by the Arrhenius plot. Ea determined from the data for 180 200 K was 42 kJ/mol and for 230 260 K was 22 kJ/mol. The higher Ea in the colder temperature range was attributed to a difference in the microstructure of ice between the two regions.

  1. Mars dayside temperature from airglow limb profiles : comparison with in situ measurements and models

    NASA Astrophysics Data System (ADS)

    Gérard, Jean-Claude; Bougher, Stephen; Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, A.

    The thermal structure of the Mars upper atmosphere is the result of the thermal balance between heating by EUV solar radiation, infrared heating and cooling, conduction and dynamic influences such as gravity waves, planetary waves, and tides. It has been derived from observations performed from different spacecraft. These include in situ measurements of orbital drag whose strength depends on the local gas density. Atmospheric temperatures were determined from the altitude variation of the density measured in situ by the Viking landers and orbital drag measurements. Another method is based on remote sensing measurements of ultraviolet airglow limb profiles obtained over 40 years ago with spectrometers during the Mariner 6 and 7 flybys and from the Mariner 9 orbiter. Comparisons with model calculations indicate that they both reflect the CO_2 scale height from which atmospheric temperatures have been deduced. Upper atmospheric temperatures varying over the wide range 270-445 K, with a mean value of 325 K were deduced from the topside scale height of the airglow vertical profile. We present an analysis of limb profiles of the CO Cameron (a(3) Pi-X(1) Sigma(+) ) and CO_2(+) doublet (B(2) Sigma_u(+) - X(2) PiΠ_g) airglows observed with the SPICAM instrument on board Mars Express. We show that the temperature in the Mars thermosphere is very variable with a mean value of 270 K, but values ranging between 150 and 400 K have been observed. These values are compared to earlier determinations and model predictions. No clear dependence on solar zenith angle, latitude or season is apparent. Similarly, exospheric variations with F10.7 in the SPICAM airglow dataset are small over the solar minimum to moderate conditions sampled by Mars Express since 2005. We conclude that an unidentified process is the cause of the large observed temperature variability, which dominates the other sources of temperature variations.

  2. Enhancing the elevated temperature performance of high voltage LiNi0.5Mn1.5O4 by V doping with in-situ carbon and polyimide encapsulation

    NASA Astrophysics Data System (ADS)

    Lee, G. H.; Kim, H. S.; Baek, S. G.; Choi, H. J.; Chung, K. Y.; Cho, B. W.; Lee, S. Y.; Lee, Yun-Sung

    2015-12-01

    We report the enhanced electrochemical performance of high voltage LiNi0.5Mn1.5O4 cathode by small amount of aliovalent doping in Li-site (Li0.995V0.005Ni0.5Mn1.5O4) and polyimide-carbon (PI-C) coating as well. Such small amount of V-doping in Li-sites leads to the crystallization of ordered spinel. The performances of the cathodes are studied in half-cell assembly at elevated temperature conditions (50, 55 and 60 °C). Although, the notable improvement in elevated temperature conditions are noted for Li0.995V0.005Ni0.5Mn1.5O4 phase at 50 °C, but not sustained while increasing to 55 and 60 °C. Nevertheless, the combined advantages of mixed conducting (ionic and electronic) features of PI-C, an excellent performance are noted for the Li0.995V0.005Ni0.5Mn1.5O4 phase after introducing the PI-C layer, irrespective of the testing temperature. Cyclic voltammetry and impedance studies are also performed to corroborate the Li-ion kinetics.

  3. Regulatory pathway analysis by high-throughput in situ hybridization

    SciTech Connect

    Visel, Axel; Carson, James P.; Oldekamp, Judit; Warnecke, Marei; Jakubcakova, Vladimira; Zhou, Xunlei; Shaw, Chad; Alvarez-Bolado, Gonzalo; Eichele, Gregor

    2007-10-01

    Automated in situ hybridization (ISH) permits construction of comprehensive atlases of gene expression patterns in mammals. When web-accessible, such atlases become searchable digital expression maps of individual genes and offer an entryway to elucidate genetic interactions and signaling pathways. An atlas housing ~1,000 spatial gene expression patterns of the mid-gestation mouse embryo was generated. Patterns were textually annotated using a controlled vocabulary comprising 90 anatomical features. Hierarchical clustering of annotations was carried out using distance scores calculated from the similarity between pairs of patterns across all anatomical structures. This ordered hundreds of complex expression patterns into a matrix that reflected the embryonic architecture and the relatedness of patterns of expression. Clustering yielded twelve distinct groups of expression pattern. Because of similarity of expression patterns within a group, members of this group may be components of regulatory cascades. We focused on one group, which is composed of 83 genes, including Pax6, an evolutionary conserved transcriptional master mediator of the development. Using functional studies, ISH on Pax6-deficient embryos and Pax6 binding site identification and validation by means of electromobility shift assays, we identified numerous genes that are transcriptionally regulated by Pax6. Hence cluster analysis of annotated gene expression patterns obtained by robotic ISH is an entryway for identification of components of signaling cascades in mammals.

  4. In situ synchrotron IR study relating temperature and heating rate to surface functional group changes in biomass.

    PubMed

    Kirtania, Kawnish; Tanner, Joanne; Kabir, Kazi Bayzid; Rajendran, Sharmen; Bhattacharya, Sankar

    2014-01-01

    Three types of woody biomass were investigated under pyrolysis condition to observe the change in the surface functional groups by Fourier transform infrared (FTIR) technique with increasing temperature under two different (5 and 150°C/min) heating rates. The experiments were carried out in situ in the infrared microscopy beamline (IRM) of the Australian Synchrotron. The capability of the beamline made it possible to focus on single particles to obtain low noise measurements without mixing with KBr. At lower heating rate, the surface functional groups were completely removed by 550°C. In case of higher heating rate, a delay was observed in losing the functional groups. Even at a high temperature, significant number of functional groups was retained after the higher heating rate experiments. This implies that at considerably high heating rates typical of industrial reactors, more functional groups will remain on the surface. PMID:24189382

  5. Transmission electron microscopy study in-situ of radiation-induced defects in copper at elevated temperatures

    SciTech Connect

    Daulton, T.L.; Kirk, M.A.; Rehn, L.E.

    1996-12-01

    Neutrons and high-energy ions incident upon a solid can initiate a displacement collision cascade of lattice atoms resulting in localized regions within the solid containing a high concentration of interstitial and vacancy point defects. These point defects can collapse into various types of dislocation loops and stacking fault tetrahedra (SFT) large enough that their lattice strain fields are visible under diffraction-contrast imaging using a Transmission Electron Microscope (TEM). The basic mechanisms driving the collapse of point defects produced in collision cascades is investigated in situ with TEM for fcc-Cu irradiated with heavy (100 keV Kr) ions at elevated temperature. The isothermal stability of these clusters is also examined in situ. Areal defect yields were observed to decrease abruptly for temperatures greater than 300 C. This decrease in defect yield is attributed to a proportional decrease in the probability of collapse of point defects into clusters. The evolution of the defect density under isothermal conditions appears to be influenced by three different rate processes active in the decline of the total defect density. These rate constants can be attributed to differences in the stability of various types of defect clusters and to different loss mechanisms. Based upon observed stabilities, estimations for the average binding enthalpies of vacancies to SFT are calculated for copper.

  6. Platinum-cobalt catalysts for the oxygen reduction reaction in high temperature proton exchange membrane fuel cells - Long term behavior under ex-situ and in-situ conditions

    NASA Astrophysics Data System (ADS)

    Schenk, Alexander; Grimmer, Christoph; Perchthaler, Markus; Weinberger, Stephan; Pichler, Birgit; Heinzl, Christoph; Scheu, Christina; Mautner, Franz-Andreas; Bitschnau, Brigitte; Hacker, Viktor

    2014-11-01

    Platinum cobalt catalysts (Pt-Co) have attracted much interest as cathode catalysts for proton exchange membrane fuel cells (PEMFCs) due to their high activity toward oxygen reduction reaction (ORR). Many of the reported catalysts show outstanding performance in ex-situ experiments. However, the laborious synthesis protocols of these Pt-Co catalysts disable an efficient and economic production of membrane electrode assemblies (MEAs). We present an economic, flexible and continuous Pt-M/C catalyst preparation method as part of a large scale membrane electrode assembly manufacturing. In comparison, the as-prepared Pt-Co/C based high temperature (HT)-PEM MEA showed an equal performance to a commercially available HT-PEM MEA during 600 h of operation under constant load, although the commercial one had a significantly higher Pt loading at the cathode.

  7. Temperature-dependent luminescent properties of Eu-Tb complexes synthesized in situ in gel glass

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Qian, Guodong; Wang, Zhiyu; Wang, Minquan

    2005-02-01

    The chelates of europium and terbium with hexafluoroacetylacetone (HFA) and triphenylphoshine oxide (TPPO), Eu /Tb(HFA)3(TPPO)2, have been synthesized in situ in gel glasses with various concentrations of Eu3+ and Tb3+ ions. The photoluminescence spectra have been measured and the characteristic transitions of Tb3+ and Eu3+ have been observed. Due to the variance of energy transfer efficiencies from Tb3+ to Eu3+, the intensity ratios of europium luminescent band to terbium band vary remarkably with measurement temperatures. In addition, the Förster mechanism has been proved to be responsible for the energy transfer between Eu3+ and Tb3+. The materials doped with Eu /Tb(HFA)3(TPPO)2 are promising for being used as a temperature detector and thermal-sensitive probe of optical fiber sensor.

  8. Modeling in situ soil enzyme activity using continuous field soil moisture and temperature data

    NASA Astrophysics Data System (ADS)

    Steinweg, J. M.; Wallenstein, M. D.

    2010-12-01

    Moisture and temperature are key drivers of soil organic matter decomposition, but there is little consensus on how climate change will affect the degradation of specific soil compounds under field conditions. Soil enzyme activities are a useful metric of soil community microbial function because they are they are the direct agents of decomposition for specific substrates in soil. However, current standard enzyme assays are conducted under optimized conditions in the laboratory and do not accurately reflect in situ enzyme activity, where diffusion and substrate availability may limit reaction rates. The Arrhenius equation, k= A*e(-Ea/RT), can be used to predict enzyme activity (k), collision frequency (A) or activation energy (Ea), but is difficult to parameterize when activities are measured under artificial conditions without diffusion or substrate limitation. We developed a modifed equation to estimate collision frequency and activation energy based on soil moisture to model in-situ enzyme activites. Our model was parameterized using data we collected from the Boston Area Climate Experiment (BACE) in Massachusetts; a multi-factor climate change experiment that provides an opportunity to assess how changes in moisture availability and temperature may impact enzyme activity. Soils were collected from three precipitation treatments and four temperature treatments arranged in a full-factorial design at the BACE site in June 2008, August 2008, January 2009 and June 2009. Enzyme assays were performed at four temperatures (4, 15, 25 and 35°C) to calculate temperature sensitivity and activation energy over the different treatments and seasons. Enzymes activities were measured for six common enzymes involved in carbon (β-glucosidase, cellobiohydrolase, xylosidase), phosphorus (phosphatase) and nitrogen cycling (N-acetyl glucosaminidase, and leucine amino peptidase). Potential enzyme activity was not significantly affected by precipitation, warming or the interaction of

  9. In situ multipurpose time-resolved spectrometer for monitoring nanoparticle generation in a high-pressure fluid

    SciTech Connect

    Wei, Shaoyu; Saitow, Ken-ichi

    2012-07-15

    We developed a multipurpose time-resolved spectrometer for studying the dynamics of nanoparticles generated by pulsed-laser ablation (PLA) in a high-pressure fluid. The apparatus consists of a high-pressure optical cell and three spectrometers for in situ measurements. The optical cell was designed for experiments at temperatures up to 400 K and pressures up to 30 MPa with fluctuations within {+-}0.1% h{sup -1}. The three spectrometers were used for the following in situ measurements at high pressures: (i) transient absorption spectrum measurements from 350 to 850 nm to investigate the dynamics of nanoparticle generation from nanoseconds to milliseconds after laser irradiation, (ii) absorption spectrum measurements from 220 to 900 nm to observe the time evolution of nanoparticles from seconds to hours after laser ablation, and (iii) dynamic light scattering measurements to track nanoparticles with sizes from 10 nm to 10 {mu}m in the time range from seconds to hours after laser ablation. By combining these three spectrometers, we demonstrate in situ measurements of gold nanoparticles generated by PLA in supercritical fluids. This is the first report of in situ time-resolved measurements of the dynamics of nanoparticles generated in a supercritical fluid.

  10. A sample chamber for in situ high-energy X-ray studies of crystal growth at deeply buried interfaces in harsh environments

    NASA Astrophysics Data System (ADS)

    de Jong, A. E. F.; Vonk, V.; Honkimäki, V.; Gorges, B.; Vitoux, H.; Vlieg, E.

    2015-06-01

    We introduce a high pressure high temperature chamber for in situ synchrotron X-ray studies. The chamber design allows for in situ studies of thin film growth from solution at deeply buried interfaces in harsh environments. The temperature can be controlled between room temperature and 1073 K while the pressure can be set as high as 50 bar using a variety of gases including N2 and NH3. The formation of GaN on the surface of a Ga13Na7 melt at 1073 K and 50 bar of N2 is presented as a performance test.

  11. Elevated temperature, nano-mechanical testing in situ in the scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Wheeler, J. M.; Michler, J.

    2013-04-01

    A general nano-mechanical test platform capable of performing variable temperature and variable strain rate testing in situ in the scanning electron microscope is described. A variety of test geometries are possible in combination with focused ion beam machining or other fabrication techniques: indentation, micro-compression, cantilever bending, and scratch testing. The system is intrinsically displacement-controlled, which allows it to function directly as a micro-scale thermomechanical test frame. Stable, elevated temperature indentation/micro-compression requires the indenter tip and the sample to be in thermal equilibrium to prevent thermal displacement drift due to thermal expansion. This is achieved through independent heating and temperature monitoring of both the indenter tip and sample. Furthermore, the apex temperature of the indenter tip is calibrated, which allows it to act as a referenced surface temperature probe during contact. A full description of the system is provided, and the effects of indenter geometry and of radiation on imaging conditions are discussed. The stabilization time and temperature distribution throughout the system as a function of temperature is characterized. The advantages of temperature monitoring and thermal calibration of the indenter tip are illustrated, which include the possibility of local thermal conductivity measurement. Finally, validation results using nanoindentation on fused silica and micro-compression of ⟨100⟩ silicon micro-pillars as a function of temperature up to 500 °C are presented, and procedures and considerations taken for these measurements are discussed. A brittle to ductile transition from fracture to splitting then plastic deformation is directly observed in the SEM for silicon as a function of temperature.

  12. Elevated temperature, nano-mechanical testing in situ in the scanning electron microscope

    SciTech Connect

    Wheeler, J. M.; Michler, J.

    2013-04-15

    A general nano-mechanical test platform capable of performing variable temperature and variable strain rate testing in situ in the scanning electron microscope is described. A variety of test geometries are possible in combination with focused ion beam machining or other fabrication techniques: indentation, micro-compression, cantilever bending, and scratch testing. The system is intrinsically displacement-controlled, which allows it to function directly as a micro-scale thermomechanical test frame. Stable, elevated temperature indentation/micro-compression requires the indenter tip and the sample to be in thermal equilibrium to prevent thermal displacement drift due to thermal expansion. This is achieved through independent heating and temperature monitoring of both the indenter tip and sample. Furthermore, the apex temperature of the indenter tip is calibrated, which allows it to act as a referenced surface temperature probe during contact. A full description of the system is provided, and the effects of indenter geometry and of radiation on imaging conditions are discussed. The stabilization time and temperature distribution throughout the system as a function of temperature is characterized. The advantages of temperature monitoring and thermal calibration of the indenter tip are illustrated, which include the possibility of local thermal conductivity measurement. Finally, validation results using nanoindentation on fused silica and micro-compression of <100> silicon micro-pillars as a function of temperature up to 500 Degree-Sign C are presented, and procedures and considerations taken for these measurements are discussed. A brittle to ductile transition from fracture to splitting then plastic deformation is directly observed in the SEM for silicon as a function of temperature.

  13. Elevated temperature, nano-mechanical testing in situ in the scanning electron microscope.

    PubMed

    Wheeler, J M; Michler, J

    2013-04-01

    A general nano-mechanical test platform capable of performing variable temperature and variable strain rate testing in situ in the scanning electron microscope is described. A variety of test geometries are possible in combination with focused ion beam machining or other fabrication techniques: indentation, micro-compression, cantilever bending, and scratch testing. The system is intrinsically displacement-controlled, which allows it to function directly as a micro-scale thermomechanical test frame. Stable, elevated temperature indentation∕micro-compression requires the indenter tip and the sample to be in thermal equilibrium to prevent thermal displacement drift due to thermal expansion. This is achieved through independent heating and temperature monitoring of both the indenter tip and sample. Furthermore, the apex temperature of the indenter tip is calibrated, which allows it to act as a referenced surface temperature probe during contact. A full description of the system is provided, and the effects of indenter geometry and of radiation on imaging conditions are discussed. The stabilization time and temperature distribution throughout the system as a function of temperature is characterized. The advantages of temperature monitoring and thermal calibration of the indenter tip are illustrated, which include the possibility of local thermal conductivity measurement. Finally, validation results using nanoindentation on fused silica and micro-compression of [100] silicon micro-pillars as a function of temperature up to 500 °C are presented, and procedures and considerations taken for these measurements are discussed. A brittle to ductile transition from fracture to splitting then plastic deformation is directly observed in the SEM for silicon as a function of temperature. PMID:23635228

  14. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.

    SciTech Connect

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; Mook, William M.; Bufford, Daniel Charles; Boyce, Brad L.; Hattar, Khalid Mikhiel; Kotula, Paul G.; Hall, Aaron Christopher

    2015-09-22

    Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock design for AD.

  15. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.

    DOE PAGESBeta

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; Mook, William M.; Bufford, Daniel Charles; Boyce, Brad L.; Hattar, Khalid Mikhiel; Kotula, Paul G.; Hall, Aaron Christopher

    2015-09-22

    Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containingmore » numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock design for AD.« less

  16. Room Temperature Deformation Mechanisms of Alumina Particles Observed from In Situ Micro-compression and Atomistic Simulations

    NASA Astrophysics Data System (ADS)

    Sarobol, Pylin; Chandross, Michael; Carroll, Jay D.; Mook, William M.; Bufford, Daniel C.; Boyce, Brad L.; Hattar, Khalid; Kotula, Paul G.; Hall, Aaron C.

    2016-01-01

    Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. The identified deformation mechanisms provide insight into feedstock design for AD.

  17. Tensile deformation mechanisms of an in-situ Ti-based metallic glass matrix composite at cryogenic temperature.

    PubMed

    Bai, J; Li, J S; Qiao, J W; Wang, J; Feng, R; Kou, H C; Liaw, P K

    2016-01-01

    Remarkable tensile ductility was first obtained in an in-situ Ti-based bulk metallic glass (BMG) composite at cryogenic temperature (77 K). The novel cryogenic tensile plasticity is related to the effective accommodation of ductile body-centered cubic dendrites at 77 K, characteristic of the prevailing slip bands and dislocations, as well as lattice disorder, which can effectively hinder the propagation of critical shear bands. The greatly increased yield strength of dendrites contributes to the high yield strength of composite at 77 K. A trend of stronger softening is observed at low temperature, and a criterion is proposed to understand the softening behavior. The current research could also provide a guidance to the promising cryogenic application of these new advanced BMG composites. PMID:27576728

  18. Tensile deformation mechanisms of an in-situ Ti-based metallic glass matrix composite at cryogenic temperature

    PubMed Central

    Bai, J.; Li, J. S.; Qiao, J. W.; Wang, J.; Feng, R.; Kou, H. C.; Liaw, P. K.

    2016-01-01

    Remarkable tensile ductility was first obtained in an in-situ Ti-based bulk metallic glass (BMG) composite at cryogenic temperature (77 K). The novel cryogenic tensile plasticity is related to the effective accommodation of ductile body-centered cubic dendrites at 77 K, characteristic of the prevailing slip bands and dislocations, as well as lattice disorder, which can effectively hinder the propagation of critical shear bands. The greatly increased yield strength of dendrites contributes to the high yield strength of composite at 77 K. A trend of stronger softening is observed at low temperature, and a criterion is proposed to understand the softening behavior. The current research could also provide a guidance to the promising cryogenic application of these new advanced BMG composites. PMID:27576728

  19. In situ stress measurement of fiber reinforced composite in low temperature state by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Nishida, Masayuki; Jing, Tian; Muslih, M. Refai; Doi, Taisei; Matsue, Tatsuya; Hanabusa, Takao

    2015-03-01

    The tungsten fiber reinforced titanium composite (W/Ti) was produced by the spot welding method. The internal stress alteration of the W/Ti composite was measured by the neutron diffractometer, DN1, which had been installed at beam port #6 in National Nuclear Energy Agency Indonesia. The two-dimensional detector and cryostat system were mounted on the DN1 diffractometer, and the residual stress alterations were measured by the in situ neutron stress measurement technique under the cooling cycles from 300 K to 10 K. Residual stresses in tungsten fiber were investigated at several temperatures. In the longitudinal fiber direction, the thermal residual stresses of tungsten fiber became a large compressive state and represented the maximum value is about -950 MPa. The calculated results of the simple elastic model agreed with the experimental results of the in situ thermal stress measurement qualitatively. It is assumed that the stresses in the fiber longitudinal direction are the dominant stresses in the W/Ti composite.

  20. Comparison of Land Skin Temperature from a Land Model, Remote Sensing, and In-situ Measurement

    NASA Technical Reports Server (NTRS)

    Wang, Aihui; Barlage, Michael; Zeng, Xubin; Draper, Clara Sophie

    2014-01-01

    Land skin temperature (Ts) is an important parameter in the energy exchange between the land surface and atmosphere. Here hourly Ts from the Community Land Model Version 4.0, MODIS satellite observations, and in-situ observations in 2003 were compared. Compared with the in-situ observations over four semi-arid stations, both MODIS and modeled Ts show negative biases, but MODIS shows an overall better performance. Global distribution of differences between MODIS and modeled Ts shows diurnal, seasonal, and spatial variations. Over sparsely vegetated areas, the model Ts is generally lower than the MODIS observed Ts during the daytime, while the situation is opposite at nighttime. The revision of roughness length for heat and the constraint of minimum friction velocity from Zeng et al. [2012] bring the modeled Ts closer to MODIS during the day, and have little effect on Ts at night. Five factors contributing to the Ts differences between the model and MODIS are identified, including the difficulty in properly accounting for cloud cover information at the appropriate temporal and spatial resolutions, and uncertainties in surface energy balance computation, atmospheric forcing data, surface emissivity, and MODIS Ts data. These findings have implications for the cross-evaluation of modeled and remotely sensed Ts, as well as the data assimilation of Ts observations into Earth system models.

  1. Temperature-dependent size exclusion chromatography for the in situ investigation of dynamic bonding/debonding reactions.

    PubMed

    Brandt, Josef; Guimard, Nathalie K; Barner-Kowollik, Christopher; Schmidt, Friedrich G; Lederer, Albena

    2013-11-01

    Polymers capable of dynamic bonding/debonding reactions are of great interest in modern day research. Potential applications can be found in the fields of self-healing materials or printable networks. Since temperature is often used as a stimulus for triggering reversible bonding reactions, an analysis operating at elevated temperatures is very useful for the in situ investigation of the reaction mechanism, as unwanted side effects can be minimized when performing the analyses at the same temperature at which the reactions occur. A temperature-dependent size exclusion chromatographic system (TD SEC) has been optimized for investigating the kinetics of retro Diels-Alder-based depolymerization of Diels-Alder polymers. The changing molecular weight distribution of the analyzed polymers during depolymerization gives valuable quantitative information on the kinetics of the reactions. Adequate data interpretation methods were developed for the correct evaluation of the chromatograms. The results are confirmed by high-temperature dynamic light scattering, thermogravimetric analysis, and time-resolved nuclear magnetic resonance spectroscopy at high temperatures. In addition, the SEC system and column material stability under application conditions were assessed using thermoanalysis methods, infrared spectroscopy, nitrogen physisorption, and scanning electron microscopy. The findings demonstrate that the system is stable and, thus, we can reliably characterize such dynamically bonding/debonding systems with TD SEC. PMID:23877179

  2. Prediction of melting temperatures in fluorescence in situ hybridization (FISH) procedures using thermodynamic models.

    PubMed

    Fontenete, Sílvia; Guimarães, Nuno; Wengel, Jesper; Azevedo, Nuno Filipe

    2016-06-01

    The thermodynamics and kinetics of DNA hybridization, i.e. the process of self-assembly of one, two or more complementary nucleic acid strands, has been studied for many years. The appearance of the nearest-neighbor model led to several theoretical and experimental papers on DNA thermodynamics that provide reasonably accurate thermodynamic information on nucleic acid duplexes and allow estimation of the melting temperature. Because there are no thermodynamic models specifically developed to predict the hybridization temperature of a probe used in a fluorescence in situ hybridization (FISH) procedure, the melting temperature is used as a reference, together with corrections for certain compounds that are used during FISH. However, the quantitative relation between melting and experimental FISH temperatures is poorly described. In this review, various models used to predict the melting temperature for rRNA targets, for DNA oligonucleotides and for nucleic acid mimics (chemically modified oligonucleotides), will be addressed in detail, together with a critical assessment of how this information should be used in FISH. PMID:25586037

  3. Estimation of in-situ thermal conductivities from temperature gradient measurements

    SciTech Connect

    Hoang, V.T.

    1980-12-01

    A mathematical model has been developed to study the effect of variable thermal conductivity of the formations, and the wellbore characteristics, on the fluid temperature behavior inside the wellbore during injection or production and after shut-in. During the injection or production period the wellbore fluid temperature is controlled mainly by the fluid flow rate and the heat lost from the fluid to the formation. During the shut-in period, the fluid temperature is strongly affected by differences in the formation thermal conductivities. Based on the results of the present analysis, two methods for estimating in-situ thermal conductivity were derived. First, the line source concept is extended to estimate values of the formation thermal conductivities utilizing the fluid temperature record during the transient period of injection or production and shut-in. The second method is applied when a well is under thermal equilibrium conditions. Values of the formation thermal conductivities can also be estimated by using a continuous temperature gradient log and by measuring the thermal conductivity of the formation at a few selected wellbore locations.

  4. In situ validation of sea surface temperatures from the GCOM-W1 AMSR2 RSS calibrated brightness temperatures

    NASA Astrophysics Data System (ADS)

    Gentemann, Chelle L.; Hilburn, Kyle A.

    2015-05-01

    Remote Sensing Systems AMSR2 v7.2 data from 25 July 2012 to 9 October 2014 are collocated with in situ sea surface temperature (SST) data. The RSS SST algorithm uses AMSR2 brightness temperatures calibrated using a methodology developed at RSS rather than using the standard JAXA AMSR2 product, which includes the JAXA calibration. The new RFI exclusion methodology used for the AMSR2 v7.2 data is described. Buoy data are quality controlled using an internal quality indicator. Daytime collocations with wind speeds of less than 6 m s-1 are excluded to avoid diurnal contamination of the results. A mean bias (AMSR2 minus in situ) of -0.04 K and standard deviation 0.55 K with 109,350 collocations is found. The geographical distribution of biases is investigated, with a small increase in biases found at higher latitudes. At lower SST the uncertainty increases and the bias. The dependencies of the bias and uncertainties on other geophysical variables are shown to be negligible. The time series of the bias and uncertainty show little variability, but a small seasonal dependence is determined to be related to a seasonal shift in wind speeds. Overall, the AMSR2 SSTs are of comparable quality to the AMSR-E SSTs and continue the climate microwave SST record that started in 1997.

  5. In-Situ X-ray Spectroscopic Studies of the Fundamental Chemistry of Pb and Pb-Bi Corrosion Processes at High Temperatures: Development and Assessment of Composite Corrosion Resistant Materials.

    SciTech Connect

    Carlo Segre

    2009-12-30

    Over the course of this project, we have a number of accomplishments. The following list is presented as a summary statement for the project. Specific details from previous Quarterly Reports are given. (1) We established that it is possible to use EXAFS to study the interface layer between a material and the liquid Pb overlayer. We have discovered that molybdenum grows a selflimiting oxide layer which does not spall even at the highest temperatures studied. There have been 2 publications resulting from these studies. (2) We have fabricated a high temperature environmental chamber capable of extending the Pb overlayer studies by varying the incident x-ray beam angle to perform depth profiling of the Pb layer. This chamber will continue to be available to nuclear materials program researchers who wish to use the MRCAT beam line. (3) We have developed a collaboration with researchers at the Paul Scherrer Institute to study corrosion layers on zircalloy. One publication has resulted from this collaboration and another is in progress. (4) We have developed a collaboration with Prof. G.R. Odette of UCSB in which we studied the local structure of Ti and Y in nanoclusters found in oxygen dispersion strengthened steels. There are two publications in progress form this collaboration and we have extended the project to anomalous small angle x-ray scattering as well as EXAFS. (5) We have promoted the use of EXAFS for the study of nuclear materials to the community over the past 4 years and we have begun to see an increase in demand for EXAFS from the community at the MRCAT beam line. (6) This grant was instrumental in nucleating interest in establishing a new Collaborative Access Team at the Advanced Photon Source, the Nuclear and Radiological Research CAT (NRR-CAT). The co-PI (Jeff Terry) is the lead investigator on this project and it has been approved by the APS Scientific Advisory Committee for further planning. The status of the NRR-CAT project is being discussed in a

  6. Influence of temperature on carbon and nitrogen dynamics during in situ aeration of aged waste in simulated landfill bioreactors.

    PubMed

    Tong, Huanhuan; Yin, Ke; Giannis, Apostolos; Ge, Liya; Wang, Jing-Yuan

    2015-09-01

    The effect of temperature on carbon and nitrogen compounds during in situ aeration of aged waste was investigated in lab-scale simulated landfill bioreactors at 35, 45 and 55 °C, respectively. The bioreactor operated at 55 °C presented the highest carbon mineralization rate in the initial stage, suggesting accelerated biodegradation rates under thermophilic conditions. The nitrogen speciation study indicated that organic nitrogen was the dominant species of total N in aerobic bioreactors due to ammonia removal. Leachate organic nitrogen was further fractionated to elucidate the fate of individual constituent. Detailed investigation revealed the higher bioconversion rates of N-humic and N-fulvic compounds compared to hydrophilic compounds in thermophilic conditions. At the end, waste material in 55 °C bioreactor was richer in highly matured humic substances (HS) verifying the high bioconversion rates. PMID:26026292

  7. Comparison of Satellite-Derived and In-Situ Observations of Ice and Snow Surface Temperatures over Greenland

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Box, Jason E.; Casey, Kimberly A.; Hook, Simon J.; Shuman, Christopher A.; Steffen, Konrad

    2008-01-01

    The most practical way to get a spatially broad and continuous measurements of the surface temperature in the data-sparse cryosphere is by satellite remote sensing. The uncertainties in satellite-derived LSTs must be understood to develop internally-consistent decade-scale land-surface temperature (LST) records needed for climate studies. In this work we assess satellite-derived "clear-sky" LST products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and LSTs derived from the Enhanced Thematic Mapper Plus (ETM+) over snow and ice on Greenland. When possible, we compare satellite-derived LSTs with in-situ air-temperature observations from Greenland Climate Network (GC-Net) automatic-weather stations (AWS). We find that MODIS, ASTER and ETM+ provide reliable and consistent LSTs under clear-sky conditions and relatively-flat terrain over snow and ice targets over a range of temperatures from -40 to 0 C. The satellite-derived LSTs agree within a relative RMS uncertainty of approx.0.5 C. The good agreement among the LSTs derived from the various satellite instruments is especially notable since different spectral channels and different retrieval algorithms are used to calculate LST from the raw satellite data. The AWS record in-situ data at a "point" while the satellite instruments record data over an area varying in size from: 57 X 57 m (ETM+), 90 X 90 m (ASTER), or to 1 X 1 km (MODIS). Surface topography and other factors contribute to variability of LST within a pixel, thus the AWS measurements may not be representative of the LST of the pixel. Without more information on the local spatial patterns of LST, the AWS LST cannot be considered valid ground truth for the satellite measurements, with RMS uncertainty approx.2 C. Despite the relatively large AWS-derived uncertainty, we find LST data are characterized by high accuracy but have uncertain absolute precision.

  8. In situ fabrication of porous graphene electrodes for high-performance energy storage.

    PubMed

    Wang, Zhong-Li; Xu, Dan; Wang, Heng-Guo; Wu, Zhong; Zhang, Xin-Bo

    2013-03-26

    In the development of energy-storage devices, simultaneously achieving high power and large energy capacity at fast rate is still a great challenge. In this paper, the synergistic effect of structure and doping in the graphene is demonstrated for high-performance lithium storage with ulftrafast and long-cycling capabilities. By an in situ constructing strategy, hierarchically porous structure, highly conductive network, and heteroatom doping are ideally combined in one graphene electrode. Compared to pristine graphene, it is found that the degree of improvement with both structure and doping effects is much larger than the sum of that with only structure effect or doping effect. Benefitting from the synergistic effect of structure and doping, the novel electrodes can deliver a high-power density of 116 kW kg(-1) while the energy density remains as high as 322 Wh kg(-1) at 80 A g(-1) (only 10 s to full charge), which provides an electrochemical storage level with the power density of a supercapacitor and the energy density of a battery, bridging the gap between them. Furthermore, the optimized electrodes exhibit long-cycling capability with nearly no capacity loss for 3000 cycles and wide temperature features with high capacities ranging from -20 to 55 °C. PMID:23383862

  9. Oil-Well Cement and C[subscript 3]S Hydration Under High Pressure as Seen by In Situ X-Ray Diffraction, Temperatures 80[degrees]C with No Additives

    SciTech Connect

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P.

    2013-01-10

    The hydration kinetics of a white cement and batches of both Class G and H oil-well cements were examined between 0 and 60 MPa, at {le}80 C, using in situ synchrotron X-ray diffraction. This gives a continuous measure of the C{sub 3}S (Ca{sub 3}SiO{sub 5}), CH (Ca(OH){sub 2}), C{sub 4}AF (Ca{sub 2}FeAlO{sub 5}), ettringite, and other phases in the hydrating slurries. Slurries prepared from single-phase C{sub 3}S; synthetic C{sub 4}AF, and gypsum; and white cement, synthetic C{sub 4}AF and gypsum were also examined. An increasing pressure enhanced the rate of hydration for all slurries. Analysis of the data, using a kinetic model, provided rate constants that were used to obtain activation volumes for C{sub 3}S hydration. For all the cement and C{sub 3}S slurries studied, similar activation volumes were obtained (average {Delta}{double_dagger}{approx}-35 cm{sup 3}/mol), indicating that the presence of cement phases other than C{sub 3}S has a modest influence on the pressure dependence of C{sub 3}S hydration. An alternative analysis, using the time at which 90% of the initial C{sub 3}S remained, gave similar activation volumes. Pressure accelerated the formation of ettringite from synthetic C{sub 4}AF in the presence of gypsum. However, in slurries containing cement, the pressure dependence of C{sub 3}S hydration plays a major role in determining the pressure dependence of ettringite formation.

  10. One-dimensional soil temperature simulation with Common Land Model by assimilating in situ observations and MODIS LST with the ensemble particle filter

    NASA Astrophysics Data System (ADS)

    Yu, Zhongbo; Fu, Xiaolei; Luo, Lifeng; Lü, Haishen; Ju, Qin; Liu, Di; Kalin, Dresden A.; Huang, Dui; Yang, Chuanguo; Zhao, Lili

    2014-08-01

    Soil temperature plays an important role in hydrology, agriculture, and meteorology. In order to improve the accuracy of soil temperature simulation, a soil temperature data assimilation system was developed based on the Ensemble Particle Filter (EnPF) and the Common Land Model (CLM), and then applied in the Walnut Gulch Experimental Watershed (WGEW) in Arizona, United States. Surface soil temperature in situ observations and Moderate Resolution Imaging Spectroradiometer Land Surface Temperature (MODIS LST) data were assimilated into the system. In this study, four different assimilation experiments were conducted: (1) assimilating in situ observations of instantaneous surface soil temperature each hour, (2) assimilating in situ observations of instantaneous surface soil temperature once per day, (3) assimilating verified MODIS LST once per day, and (4) assimilating original MODIS LST once per day. These four experiments reflect a transition from high-quality and more frequent in situ observations to lower quality and less frequent remote sensing data in the data assimilation system. The results from these four experiments show that the assimilated results are better than the simulated results without assimilation at all layers except the bottom layer, while the superiority gradually diminishes as the quality and frequency of the observations decrease. This demonstrates that remote sensing data can be assimilated using the ensemble particle filter in poorly gauged catchments to obtain highly accurate soil variables (e.g., soil moisture, soil temperature). Meanwhile, the results also demonstrate that the ensemble particle filter is effective in assimilating soil temperature observations to improve simulations, but the performance of the data assimilation method is affected by the frequency of assimilation and the quality of the input data.

  11. Comparison of in-situ, aircraft, and satellite based land surface temperature measurements

    NASA Astrophysics Data System (ADS)

    Baker, B.; Krishna, P.; Meyers, T. P.

    2013-12-01

    and surface temperature (LST) is a key variable used in surface energy budget studies, and in near-real time is assimilated into land surface models for short and medium range forecasts. Observations of LST over multiple years are also critical for climate trend assessment. However, accurate in-situ measurements of LST over continents are not yet available for the whole globe and are not routinely conducted at weather stations. Recently an effort has been underway to validate LST sensed remotely from satellites to the actual measured skin temperature using data from the United States Climate Reference Network (USCRN). The goal of this work is to quantify the spatial variability and the representativeness of the single-point skin temperature measurement already being made at USCRN sites. NOAA/ATDD is collaborating with the University of Tennessee Space Institute's (UTSI) Aviation Systems and Flight Research Department in Tullahoma, TN to utilize an instrumented aircraft to perform measurements of Earth's skin temperature over selected USCRN sites in the continental U.S. Airborne remote sensing is a powerful tool to assess the spatial variability of LST over a location with sufficient sampling density and has the operational flexibility depending on the study requirements. We will present the results from airborne campaigns made concurrently with satellite overpasses over a grassland site and a deciduous forest site, compare the relationship of surface temperature to air temperature at a number of CRN sites and show results of an intercomparison between the JPL reference skin temperature measurement and the CRN sensor.

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

    PubMed

    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. PMID:27131721

  13. 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.

  14. In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

    NASA Technical Reports Server (NTRS)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P. E.; Kear, B.; Gallois, B.

    1991-01-01

    Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  15. In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

    NASA Technical Reports Server (NTRS)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P.; Gallois, B.; Kear, B.

    1990-01-01

    Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  16. Kinetics of methane hydrate decomposition studied via in situ low temperature X-ray powder diffraction.

    PubMed

    Everett, S Michelle; Rawn, Claudia J; Keffer, David J; Mull, Derek L; Payzant, E Andrew; Phelps, Tommy J

    2013-05-01

    Gas hydrate is known to have a slowed decomposition rate at ambient pressure and temperatures below the melting point of ice. As hydrate exothermically decomposes, gas is released and water of the clathrate cages transforms into ice. Based on results from the decomposition of three nominally similar methane hydrate samples, the kinetics of two regions, 180-200 and 230-260 K, within the overall decomposition range 140-260 K, were studied by in situ low temperature X-ray powder diffraction. The kinetic rate constants, k(a), and the reaction mechanisms, n, for ice formation from methane hydrate were determined by the Avrami model within each region, and activation energies, E(a), were determined by the Arrhenius plot. E(a) determined from the data for 180-200 K was 42 kJ/mol and for 230-260 K was 22 kJ/mol. The higher E(a) in the colder temperature range was attributed to a difference in the microstructure of ice between the two regions. PMID:23557375

  17. the validation of FORMOSAT-3/COSMIC atmospheric retrieval profile with high-resolution in-situ sounding data

    NASA Astrophysics Data System (ADS)

    Lin, P.-H.

    2009-04-01

    This study collected the high-resolution data of dropsonde, balloon radiosonde as well as MIST-sonde of driftsonde system during SoMWEX 2008, DOTSATR 2008 and THORPEX/PARC 2008. These in-situ atmospheric sounding data from the same temperature/humidity sensor, Vaisala RS92-PTU module, in these weather experiments around western Pacific and Taiwan region provide the unique reference for comparing FORMOSAT-3/COSMIC temperature and humidity profiles. FORMOSAT-3/COSMIC, similar to CHAMP GPS radio occultation soundings, was launched in 2006 and had provided global coverage of temperature and humidity profiles for numerical weather prediction. The near geo-location (less than 200 km radius) and near synchronized time window (less than 2 hours) are the matching conditions to compare the remote and in-situ profiles with 100 m vertical resolution from surface to upper air. 51 pairs of comparison showed that FORMOSAT-3/COSMIC has -0.06±0.88℃ cold bias (0.53±3.34℃ warm bias) below (above) 10 km height. The humidity profile has dry bias from -0.38 to -0.07 g/kg from lower atmosphere to higher altitude.The averaged slant distance (~130km) from FORMOSAT-3/COSMIC might cause the lager deviation on moisture profile to the near-vertical in-situ radio soundings.

  18. Determination of Coherency and Rigidity Temperatures in Al-Cu Alloys Using In Situ Neutron Diffraction During Casting

    NASA Astrophysics Data System (ADS)

    Drezet, Jean-Marie; Mireux, Bastien; Szaraz, Zoltan; Pirling, Thilo

    2014-08-01

    The rigidity temperature of a solidifying alloy is the temperature at which the solid phase is sufficiently coalesced to transmit tensile stress. It is a major input parameter in numerical modeling of solidification processes as it defines the point at which thermally induced deformations start to generate internal stresses in a casting. This temperature has been determined for an Al-13 wt.% Cu alloy using in situ neutron diffraction during casting in a dog-bone-shaped mold. This setup allows the sample to build up internal stress naturally as its contraction is not possible. The cooling on both sides of the mold induces a hot spot at the middle of the sample that is irradiated by neutrons. Diffraction patterns are recorded every 11 s using a large detector, and the very first change of diffraction angles allows for the determination of the rigidity temperature. We measured rigidity temperatures equal to 557°C and 548°C depending on the cooling rate for grain refined Al-13 wt.% Cu alloys. At a high cooling rate, rigidity is reached during the formation of the eutectic phase. In this case, the solid phase is not sufficiently coalesced to sustain tensile load and thus cannot avoid hot tear formation.

  19. A review of uncertainty in in situ measurements and data sets of sea surface temperature

    NASA Astrophysics Data System (ADS)

    Kennedy, John J.

    2014-03-01

    Archives of in situ sea surface temperature (SST) measurements extend back more than 160 years. Quality of the measurements is variable, and the area of the oceans they sample is limited, especially early in the record and during the two world wars. Measurements of SST and the gridded data sets that are based on them are used in many applications so understanding and estimating the uncertainties are vital. The aim of this review is to give an overview of the various components that contribute to the overall uncertainty of SST measurements made in situ and of the data sets that are derived from them. In doing so, it also aims to identify current gaps in understanding. Uncertainties arise at the level of individual measurements with both systematic and random effects and, although these have been extensively studied, refinement of the error models continues. Recent improvements have been made in the understanding of the pervasive systematic errors that affect the assessment of long-term trends and variability. However, the adjustments applied to minimize these systematic errors are uncertain and these uncertainties are higher before the 1970s and particularly large in the period surrounding the Second World War owing to a lack of reliable metadata. The uncertainties associated with the choice of statistical methods used to create globally complete SST data sets have been explored using different analysis techniques, but they do not incorporate the latest understanding of measurement errors, and they want for a fair benchmark against which their skill can be objectively assessed. These problems can be addressed by the creation of new end-to-end SST analyses and by the recovery and digitization of data and metadata from ship log books and other contemporary literature.

  20. Experimental Investigation and High Resolution Simulation of In-Situ Combustion Processes

    SciTech Connect

    Margot Gerritsen; Tony Kovscek

    2008-04-30

    This final technical report describes work performed for the project 'Experimental Investigation and High Resolution Numerical Simulator of In-Situ Combustion Processes', DE-FC26-03NT15405. In summary, this work improved our understanding of in-situ combustion (ISC) process physics and oil recovery. This understanding was translated into improved conceptual models and a suite of software algorithms that extended predictive capabilities. We pursued experimental, theoretical, and numerical tasks during the performance period. The specific project objectives were (i) identification, experimentally, of chemical additives/injectants that improve combustion performance and delineation of the physics of improved performance, (ii) establishment of a benchmark one-dimensional, experimental data set for verification of in-situ combustion dynamics computed by simulators, (iii) develop improved numerical methods that can be used to describe in-situ combustion more accurately, and (iv) to lay the underpinnings of a highly efficient, 3D, in-situ combustion simulator using adaptive mesh refinement techniques and parallelization. We believe that project goals were met and exceeded as discussed.

  1. Deformation mechanisms in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures

    DOE PAGESBeta

    Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K

    2014-10-22

    In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticitymore » theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.« less

  2. Deformation mechanisms in a precipitation-strengthened ferritic super alloy revealed by in situ neutron dffraction studies at elevated temperatures

    SciTech Connect

    Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Teng, Zhenke; Wu, Wei; Liaw, Peter K.

    2015-01-01

    The ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)AlB2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.

  3. Deformation mechanisms in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures

    SciTech Connect

    Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K

    2014-10-22

    In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.

  4. High frequency, high resolution in situ measurement of Dissolved Organic Carbon

    NASA Astrophysics Data System (ADS)

    Hu, I. H.; Hemond, H.

    2013-12-01

    Dissolved Organic Carbon (DOC) is an important part of the carbon cycle in aquatic ecosystems and plays a fundamental role in numerous biogeochemical processes. Fast and accurate quantification of its concentration is necessary for several applications. For instance, determination of benthic fluxes of DOC via the eddy correlation (EC) method requires a sensor capable of precisely measuring DOC concentrations at a small point location, at a speed of several Hz. Such a sensor would enable the development of EC as a minimally invasive, in situ alternative to existing methods of DOC flux estimation, which currently include benthic chambers and sediment core incubations. A proof of concept instrument has been created capable of detecting naturally occurring levels of DOC at high speed via fluorescence measurements. Designed with the EC application in mind, the system utilizes optical fibers to transmit excitation and emission light, enabling in situ measurements at high spatial resolution. Emitted fluorescence light is passed through a tunable monochromator before reaching a photomultiplier tube; light level, and therefore solute concentration, is determined by photon counting. Preliminary results indicated that 100 Hz measurements of a 10 ppm humic acid solution were precise within 5%. The use of a tunable monochromator not only allows flexibility in detection wavelength, but also enables scans of the emission spectrum. The instrument thus is a dual-function device capable of both characterizing the chemistry of the water (e.g. characterizing the DOC present, or identifying additional compounds), and measuring fluorescence at selected wavelengths for EC and other applications.

  5. The CORA dataset: validation and diagnostics of in-situ ocean temperature and salinity measurements

    NASA Astrophysics Data System (ADS)

    Cabanes, C.; Grouazel, A.; von Schuckmann, K.; Hamon, M.; Turpin, V.; Coatanoan, C.; Paris, F.; Guinehut, S.; Boone, C.; Ferry, N.; de Boyer Montégut, C.; Carval, T.; Reverdin, G.; Pouliquen, S.; Le Traon, P.-Y.

    2013-01-01

    The French program Coriolis, as part of the French operational oceanographic system, produces the COriolis dataset for Re-Analysis (CORA) on a yearly basis. This dataset contains in-situ temperature and salinity profiles from different data types. The latest release CORA3 covers the period 1990 to 2010. Several tests have been developed to ensure a homogeneous quality control of the dataset and to meet the requirements of the physical ocean reanalysis activities (assimilation and validation). Improved tests include some simple tests based on comparison with climatology and a model background check based on a global ocean reanalysis. Visual quality control is performed on all suspicious temperature and salinity profiles identified by the tests, and quality flags are modified in the dataset if necessary. In addition, improved diagnostic tools have been developed - including global ocean indicators - which give information on the quality of the CORA3 dataset and its potential applications. CORA3 is available on request through the MyOcean Service Desk (http://www.myocean.eu/).

  6. Two stage, low temperature, catalyzed fluidized bed incineration with in situ neutralization for radioactive mixed wastes

    SciTech Connect

    Wade, J.F.; Williams, P.M.

    1995-05-17

    A two stage, low temperature, catalyzed fluidized bed incineration process is proving successful at incinerating hazardous wastes containing nuclear material. The process operates at 550{degrees}C and 650{degrees}C in its two stages. Acid gas neutralization takes place in situ using sodium carbonate as a sorbent in the first stage bed. The feed material to the incinerator is hazardous waste-as defined by the Resource Conservation and Recovery Act-mixed with radioactive materials. The radioactive materials are plutonium, uranium, and americium that are byproducts of nuclear weapons production. Despite its low temperature operation, this system successfully destroyed poly-chlorinated biphenyls at a 99.99992% destruction and removal efficiency. Radionuclides and volatile heavy metals leave the fluidized beds and enter the air pollution control system in minimal amounts. Recently collected modeling and experimental data show the process minimizes dioxin and furan production. The report also discusses air pollution, ash solidification, and other data collected from pilot- and demonstration-scale testing. The testing took place at Rocky Flats Environmental Technology Site, a US Department of Energy facility, in the 1970s, 1980s, and 1990s.

  7. Beamline electrostatic levitator for in situ high energy x-ray diffraction studies of levitated solids and liquids

    SciTech Connect

    Gangopadhyay, A.K.; Lee, G.W.; Kelto, K.F.; Rogers, J.R.; Goldman, A.I.; Robinson, D.S.; Rathz, T.J.; Hyers, R.W.

    2010-07-19

    Determinations of the phase formation sequence, crystal structures and the thermo-physical properties of materials at high temperatures are hampered by contamination from the sample container and environment. Containerless processing techniques, such as electrostatic (ESL), electromagnetic, aerodynamic, and acoustic levitation, are most suitable for these studies. An adaptation of ESL for in situ structural studies of a wide range of materials using high energy (30-130 keV) x rays at a synchrotron source is described here. This beamline ESL (BESL) allows the in situ determination of the atomic structures of equilibrium solid and liquid phases, undercooled liquids and time-resolved studies of solid-solid and liquid-solid phase transformations. The use of area detectors enables the rapid acquisition of complete diffraction patterns over a wide range (0.5-14 {angstrom}{sup -1}) of reciprocal space. The wide temperature range (300-2500 K), containerless processing environment under high vacuum (10{sup -7}-10{sup -8} Torr), and fast data acquisition capability, make BESL particularly well suited for phase stability studies of high temperature solids and liquids. An additional, but important, feature of BESL is the capability for simultaneous measurements of a host of thermo-physical properties including the specific heat, enthalpy of transformation, solidus and liquidus temperatures, density, viscosity, and surface tension, all on the same sample during the structural measurements.

  8. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    SciTech Connect

    Feng, Zhili; Wang, Xun-Li; David, Stan A; Choo, Hahn; Hubbard, Camden R; Woo, Wan Chuck; Brown, D. W.; Clausen, B; An, Ke

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in situ, time resolved neutron diffraction technique. A method was developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld.

  9. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    SciTech Connect

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Brown, D. W.; Clausen, B; An, Ke; Choo, Hahn; Hubbard, Camden R; David, Stan A

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in-situ, time-resolved neutron diffraction technique. A method is developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld.

  10. In meso in situ serial X-ray crystallography of soluble and membrane proteins at cryogenic temperatures.

    PubMed

    Huang, Chia Ying; Olieric, Vincent; Ma, Pikyee; Howe, Nicole; Vogeley, Lutz; Liu, Xiangyu; Warshamanage, Rangana; Weinert, Tobias; Panepucci, Ezequiel; Kobilka, Brian; Diederichs, Kay; Wang, Meitian; Caffrey, Martin

    2016-01-01

    Here, a method for presenting crystals of soluble and membrane proteins growing in the lipid cubic or sponge phase for in situ diffraction data collection at cryogenic temperatures is introduced. The method dispenses with the need for the technically demanding and inefficient crystal-harvesting step that is an integral part of the lipid cubic phase or in meso method of growing crystals. Crystals are dispersed in a bolus of mesophase sandwiched between thin plastic windows. The bolus contains tens to hundreds of crystals, visible with an in-line microscope at macromolecular crystallography synchrotron beamlines and suitably disposed for conventional or serial crystallographic data collection. Wells containing the crystal-laden boluses are removed individually from hermetically sealed glass plates in which crystallization occurs, affixed to pins on goniometer bases and excess precipitant is removed from around the mesophase. The wells are snap-cooled in liquid nitrogen, stored and shipped in Dewars, and manually or robotically mounted on a goniometer in a cryostream for diffraction data collection at 100 K, as is performed routinely with standard, loop-harvested crystals. The method is a variant on the recently introduced in meso in situ serial crystallography (IMISX) method that enables crystallographic measurements at cryogenic temperatures where crystal lifetimes are enormously enhanced whilst reducing protein consumption dramatically. The new approach has been used to generate high-resolution crystal structures of a G-protein-coupled receptor, α-helical and β-barrel transporters and an enzyme as model integral membrane proteins. Insulin and lysozyme were used as test soluble proteins. The quality of the data that can be generated by this method was attested to by performing sulfur and bromine SAD phasing with two of the test proteins. PMID:26894538

  11. In meso in situ serial X-ray crystallography of soluble and membrane proteins at cryogenic temperatures

    PubMed Central

    Huang, Chia-Ying; Olieric, Vincent; Ma, Pikyee; Howe, Nicole; Vogeley, Lutz; Liu, Xiangyu; Warshamanage, Rangana; Weinert, Tobias; Panepucci, Ezequiel; Kobilka, Brian; Diederichs, Kay; Wang, Meitian; Caffrey, Martin

    2016-01-01

    Here, a method for presenting crystals of soluble and membrane proteins growing in the lipid cubic or sponge phase for in situ diffraction data collection at cryogenic temperatures is introduced. The method dispenses with the need for the technically demanding and inefficient crystal-harvesting step that is an integral part of the lipid cubic phase or in meso method of growing crystals. Crystals are dispersed in a bolus of mesophase sandwiched between thin plastic windows. The bolus contains tens to hundreds of crystals, visible with an in-line microscope at macromolecular crystallography synchrotron beamlines and suitably disposed for conventional or serial crystallographic data collection. Wells containing the crystal-laden boluses are removed individually from hermetically sealed glass plates in which crystallization occurs, affixed to pins on goniometer bases and excess precipitant is removed from around the mesophase. The wells are snap-cooled in liquid nitrogen, stored and shipped in Dewars, and manually or robotically mounted on a goniometer in a cryostream for diffraction data collection at 100 K, as is performed routinely with standard, loop-harvested crystals. The method is a variant on the recently introduced in meso in situ serial crystallography (IMISX) method that enables crystallo­graphic measurements at cryogenic temperatures where crystal lifetimes are enormously enhanced whilst reducing protein consumption dramatically. The new approach has been used to generate high-resolution crystal structures of a G-protein-coupled receptor, α-helical and β-barrel transporters and an enzyme as model integral membrane proteins. Insulin and lysozyme were used as test soluble proteins. The quality of the data that can be generated by this method was attested to by performing sulfur and bromine SAD phasing with two of the test proteins. PMID:26894538

  12. In situ structural analysis of calcium aluminosilicate glasses under high pressure.

    PubMed

    Muniz, R F; de Ligny, D; Martinet, C; Sandrini, M; Medina, A N; Rohling, J H; Baesso, M L; Lima, S M; Andrade, L H C; Guyot, Y

    2016-08-10

    In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH(-)-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ([Formula: see text][T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q (n) species to Q (n-1). In the case of Al-rich glass, the Al in the smallest Q (n) units evolved from tetrahedral to higher-coordinated Al (([5])Al and ([6])Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network. PMID:27300313

  13. Synthesis and in situ high pressure Raman spectroscopy study of AlN dendritic crystal

    SciTech Connect

    Li, Xuefei; Kong, Lingnan; Shen, Longhai; Yang, Jinghai; Gao, Ming; Hu, Tingjing; Wu, Xingtong; Li, Ming

    2013-09-01

    Graphical abstract: - Highlights: • The sample is the typical dendritic crystal structure. • The phase transition of AlN dendritic crystal is researched. • The Raman signal of rock salt AlN is observed under high pressure. • Grüneisen parameters and phase transition criterion are discussed. - Abstract: AlN dendritic crystal was synthesized by the direct current arc discharge apparatus. X-ray diffraction (XRD) patterns indicated that the sample is hexagonal AlN and preferentially grown along the a-axis direction. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images reveal that the product mainly consists of micron AlN dendritic crystal. In situ high pressure Raman spectra of AlN dendritic crystal has been measured in the pressure ranged from ambient pressure to 32.97 GPa at room temperature by using diamond anvil cell. According to the Raman scattering results, the phase transition from the wurtzite to rock salt was found at about 20.73 GPa by the appearance of a new Raman signal. Above 20.73 GPa, a new Raman signal due to disorder-activated Raman scattering in the rock salt phase was observed. In addition, the pressure coefficients, phase transition criterion, and mode Grüneisen parameters of AlN dendritic crystal, which could be different from that of other AlN, are carefully discussed.

  14. Injectable Polymerized High Internal Phase Emulsions with Rapid in Situ Curing

    PubMed Central

    2015-01-01

    Polymerized high internal phase emulsions (polyHIPEs) have been utilized in the creation of injectable scaffolds that cure in situ to fill irregular bone defects and potentially improve tissue healing. Previously, thermally initiated scaffolds required hours to cure, which diminished the potential for clinical translation. Here, a double-barrel syringe system for fabricating redox-initiated polyHIPEs with dramatically shortened cure times upon injection was demonstrated with three methacrylated macromers. The polyHIPE cure time, compressive properties, and pore architecture were investigated with respect to redox initiator chemistry and concentration. Increased concentrations of redox initiators reduced cure times from hours to minutes and increased the compressive modulus and strength without compromising the pore architecture. Additionally, storage of the uncured emulsion at reduced temperatures for 6 months was shown to have minimal effects on the resulting graft properties. These studies indicate that the uncured emulsions can be stored in the clinic until they are needed and then rapidly cured after injection to rigid, high-porosity scaffolds. In summary, we have improved upon current methods of generating injectable polyHIPE grafts to meet translational design goals of long storage times and rapid curing (<15 min) without sacrificing porosity or mechanical properties. PMID:25006990

  15. In situ structural analysis of calcium aluminosilicate glasses under high pressure

    NASA Astrophysics Data System (ADS)

    Muniz, R. F.; de Ligny, D.; Martinet, C.; Sandrini, M.; Medina, A. N.; Rohling, J. H.; Baesso, M. L.; Lima, S. M.; Andrade, L. H. C.; Guyot, Y.

    2016-08-01

    In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH‑-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ({ν\\text{B}} [T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q n species to Q n‑1. In the case of Al-rich glass, the Al in the smallest Q n units evolved from tetrahedral to higher-coordinated Al ([5]Al and [6]Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

  16. An in situ tensile test apparatus for polymers in high pressure hydrogen

    NASA Astrophysics Data System (ADS)

    Alvine, K. J.; Kafentzis, T. A.; Pitman, S. G.; Johnson, K. I.; Skorski, D.; Tucker, J. C.; Roosendaal, T. J.; Dahl, M. E.

    2014-10-01

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex situ measurements of mechanical properties problematic. Designing in situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials such as Nd. Here we detail the design and operation of a solenoid based in situ tensile tester under high-pressure hydrogen environments up to 42 MPa (6000 psi). Modulus data from high-density polyethylene samples tested under high-pressure hydrogen at 35 MPa (5000 psi) are also reported as compared to baseline measurements taken in air.

  17. An In-situ Tensile Test Apparatus for Polymers in High Pressure Hydrogen

    SciTech Connect

    Alvine, Kyle J.; Kafentzis, Tyler A.; Pitman, Stan G.; Johnson, Kenneth I.; Skorski, Daniel C.; Tucker, Joseph C.; Roosendaal, Timothy J.; Dahl, Michael E.

    2014-10-10

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex-situ measurements of mechanical properties problematic. Designing in-situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials like Nd. Here we detail the design and operation of a solenoid based in-situ tensile tester under high-pressure hydrogen environments up to 5,000 psi. Modulus data from high-density polyethylene (HDPE) samples tested under high-pressure hydrogen are also reported as compared to baseline measurements taken in air.

  18. An in situ tensile test apparatus for polymers in high pressure hydrogen

    SciTech Connect

    Alvine, K. J. Kafentzis, T. A.; Pitman, S. G.; Johnson, K. I.; Skorski, D.; Tucker, J. C.; Roosendaal, T. J.; Dahl, M. E.

    2014-10-15

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex situ measurements of mechanical properties problematic. Designing in situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials such as Nd. Here we detail the design and operation of a solenoid based in situ tensile tester under high-pressure hydrogen environments up to 42 MPa (6000 psi). Modulus data from high-density polyethylene samples tested under high-pressure hydrogen at 35 MPa (5000 psi) are also reported as compared to baseline measurements taken in air.

  19. Geostatistical Analysis of Surface Temperature and In-Situ Soil Moisture Using LST Time-Series from Modis

    NASA Astrophysics Data System (ADS)

    Sohrabinia, M.; Rack, W.; Zawar-Reza, P.

    2012-07-01

    The objective of this analysis is to provide a quantitative estimate of the fluctuations of land surface temperature (LST) with varying near surface soil moisture (SM) on different land-cover (LC) types. The study area is located in the Canterbury Plains in the South Island of New Zealand. Time series of LST from the MODerate resolution Imaging Spectro-radiometer (MODIS) have been analysed statistically to study the relationship between the surface skin temperature and near-surface SM. In-situ measurements of the skin temperature and surface SM with a quasi-experimental design over multiple LC types are used for validation. Correlations between MODIS LST and in-situ SM, as well as in-situ surface temperature and SM are calculated. The in-situ measurements and MODIS data are collected from various LC types. Pearson's r correlation coefficient and linear regression are used to fit the MODIS LST and surface skin temperature with near-surface SM. There was no significant correlation between time-series of MODIS LST and near-surface SM from the initial analysis, however, careful analysis of the data showed significant correlation between the two parameters. Night-time series of the in-situ surface temperature and SM from a 12 hour period over Irrigated-Crop, Mixed-Grass, Forest, Barren and Open- Grass showed inverse correlations of -0.47, -0.68, -0.74, -0.88 and -0.93, respectively. These results indicated that the relationship between near-surface SM and LST in short-terms (12 to 24 hours) is strong, however, remotely sensed LST with higher temporal resolution is required to establish this relationship in such time-scales. This method can be used to study near-surface SM using more frequent LST observations from a geostationary satellite over the study area.

  20. Preparation of a Paeonol-Containing Temperature-Sensitive In Situ Gel and Its Preliminary Efficacy on Allergic Rhinitis

    PubMed Central

    Chu, Kedan; Chen, Lidian; Xu, Wei; Li, Huang; Zhang, Yuqin; Xie, Weirong; Zheng, Jian

    2013-01-01

    In this paper, the optimal composition of a paeonol temperature-sensitive in situ gel composed of poloxamer 407 (P407) was determined, and a preliminary study of its effect on allergic rhinitis was performed. The optimal composition of the paeonol temperature-sensitive in situ gel included 2% paeonol inclusion, 22% P407, 2% poloxamer 188 (P188) and 2% PEG6000, as assessed by thermodynamic and rheological studies. The toad palate model was employed to study the toxicity of the paeonol temperature-sensitive in situ gel on the nasal mucosa. The result of this experiment showed low toxicity to cilia, which allows the gel to be used for nasal administration. The Franz diffusion cell method was used to study the in vitro release of paeonol and suggested that the in vitro release was in line with the Higuchi equation. This result suggests that the paeonol could be absorbed into the body through mucous membranes and had some characteristics of a sustained effect. Finally, the guinea pig model of ovalbumin sensitized allergic rhinitis was used to evaluate the preliminary efficacy of the gel, with the paeonol temperature-sensitive in situ gel showing a significant effect on the guinea pig model of sensitized allergic rhinitis (AR). PMID:23525047

  1. Large palpable ductal carcinoma in situ is Her-2 positive with high nuclear grade

    PubMed Central

    Monabati, Ahmad; Sokouti, Ali-Reza; Noori, Sadat Noori; Safaei, Akbar; Talei, Abd-Rasul; Omidvari, Shapoor; Azarpira, Negar

    2015-01-01

    Ductal carcinoma in situ (DCIS) of the breast is a heterogeneous group with variable clinical presentation. The exact molecular mechanism is not known why some ductal carcinomas may reach to such a large size but still remains in situ. Although, molecular classification of DCIS lesions and nuclear grading are important for identification of more aggressive lesions but it is not sufficient. Our aim was to examine the expression pattern of immunohistochemical (IHC) markers of ER, PR, HER-2 in palpable DCIS lesions and compare with clinicopathological findings. Our center is referral hospital from South of Iran. Samples were obtained from fifty four patients with a diagnosis of palpable DCIS. Equivocal (2+) case in HER-2 IHC testing was more characterized by chromogenic in situ hybridization. The positive frequency of HER2, ER, and PR was 92%, 48%, and 37% respectively. Palpable DCIS lesions were significantly more HER-2 positive (92%). The DCIS cases were more likely to be of high nuclear grade (grade III) and Her-2 positive cases were more likely to be of high nuclear grade than intermediate grade. All ER negative tumors had high nuclear grade. The Her-2 positivity is suggested as the most important factor responsible for marked in situ proliferation and production of palpable mass. PMID:26097582

  2. 4-Diamond Formation from Amorphouse Carbon and Graphite in the Presence of COH Fluids : An InSitu High-Pressure and -Temperature Laser-Heated Diamond Anvil Cell Experimental Study

    SciTech Connect

    Zhang, J.; Prakapenka, V.; Kubo, A.; Kavner, A.; Green, H.W.; Dobrzhinetskaya, L.

    2011-10-14

    Microdiamonds from orogenic belts contain nanometer-size fluid inclusions suggesting diamond formation from supercritical carbon - oxygen - hydrogen (COH) fluids. Here we report experimental results of diamond nucleation from amorphous carbon and polycrystalline graphite in the presence of COH fluids in a laser-heated diamond anvil cell. Our results show that: (i) diamonds can nucleate from graphite or amorphous carbon at pressures of 9-11 GPa and temperatures of 1200-1400 K in the presence of COH fluids; (ii) it is easier to nucleate diamond from amorphous carbon than from graphite with or without the COH fluids; and (iii) the fluid from decomposition of glucose is more efficient in promoting the graphite-to-diamond transformation than the fluid from decomposition of oxalic acid dihydrate. Carbon crystallinity has strong effects on the kinetics of diamond nucleation and growth. The experimental results demonstrated the critical role of presence and composition of supercritical COH fluids for promoting the graphite-to-diamond transformation.

  3. In-Situ F2-Region Plasma Density and Temperature Measurements from the International Space Station

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria; Wright, Kenneth; Minow, Joseph

    2008-01-01

    The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006. is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). This instrument package provides a new opportunity lor collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shOWS examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes lor monitoring mid and low latitude plasma processes.

  4. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    NASA Astrophysics Data System (ADS)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-12-01

    Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnOx) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnOx/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnOx layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO4 and then surface-deposition of MnOx particles from the bulk phase. The MnOx particles assembled with nanosheets were uniformly coated on the PET fibers. MnOx/PET showed good activity for HCHO decomposition at room temperature which followed the Mars-van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m3, space velocity ∼17,000 h-1 and relative humidity∼50%. This research provides a facile method to deposit active MnOx onto polymers with low air resistance, and composite MnOx/PET material is promising for indoor air purification.

  5. In situ synthesis of TiO2/polyethylene terephthalate hybrid nanocomposites at low temperature

    NASA Astrophysics Data System (ADS)

    Peng, Xinyan; Ding, Enyong; Xue, Feng

    2012-06-01

    TiO2 nanoflowers were in situ grown on polyethylene terephthalate (PET) non-woven fabric by hydrolysis of TiCl4 in aqueous solution in the presence of nanocrystal cellulose grafted PET fabric (NCC-g-PET) at a low temperature of 70 °C. Nanocrystal cellulose (NCC) pre-grafted on PET fabric acted as hydrophilic substrate and morphology inducing agent to promote the nucleation and crystal growth of TiO2. Detailed information on the synthetic process was presented. The resulting samples were characterized using FE-SEM, EDS, ATR-IR, Raman microscopy, XRD and TG analysis. The photocatalytic activity of the samples was evaluated by the degradation of orange methyl under solar light. Characteristic results indicate that rutile TiO2 nanoflowers have grown abundantly on PET non-woven fabric, and the established hydrogen bonding strengthens the interfacial interaction between the inorganic particles and the polymeric substrates. The methyl orange decoloration test under natural solar light demonstrates that this TiO2/PET hybrid nanocomposites exhibit excellent self-cleaning performance which is expected to have a good potential for commercialization.

  6. An Assessment on Integrating Satellite and in-Situ Data to Generate Globally Gridded Surface Temperature Products

    NASA Astrophysics Data System (ADS)

    Stegall, S. T.; Zhang, H. M.; Shi, L.

    2014-12-01

    Presently there exist data gaps in global surface temperature products such as NOAATemp and other international datasets. Studies have indicated that these data gaps may have an impact on derived global temperature trends in these datasets, particularly in the recent decade or so. This is an important area for improving the NOAATemp dataset. While gaps in in situ data coverage are expected to continue in the foreseeable future, satellite data are available over these regions, and some studies have shown the potential usefulness of satellite data to mitigate the impact of these gaps in in situdata. Thus it is important to systematically evaluate the potential utility of satellite data in gap filling, such as using the NOAA NCDC's 2-m air temperature dataset retrieved from NOAA POES satellite's HIRS measurements. Comparisons of monthly gridded HIRS T2m to NOAATemp will be presented. Similarities and differences in spatial patterns, global averages, and trends between the two data sets will be shown and discussed, including zonal, meridional, and global averages and other statistics. High-quality USCRN station data and HIRS will also be compared, and RMSE and biases will be analyzed and presented.

  7. Characterization of Cross-Sectioned Gallium Nitride High-Electron-Mobility Transistors with In Situ Biasing

    NASA Astrophysics Data System (ADS)

    Hilton, A. M.; Brown, J. L.; Moore, E. A.; Hoelscher, J. A.; Heller, E. R.; Dorsey, D. L.

    2015-10-01

    AlGaN/GaN high-electron-mobility transistors (HEMTs) were characterized in cross-section by Kelvin probe force microscopy (KPFM) during in situ biasing. The HEMTs used in this study were specially designed to maintain full and representative transistor functionality after cross-sectioning perpendicular to the gate width dimension to expose the active channel from source to drain. A cross-sectioning procedure was established that produces samples with high-quality surfaces and minimal degradation in initial transistor performance. A detailed description of the cross-sectioning procedure is provided. Samples were characterized by KPFM, effectively mapping the surface potential of the device in two-dimensional cross-section, including under metallization layers (i.e., gate, field plates, and ohmic contacts). Under the gate and field plate layers are where electric field, temperature, and temperature gradients are all most commonly predicted to have peak values, and where degradation and failure are most likely, and so this is where direct measurements are most critical. In this work, the surface potential of the operating device was mapped in cross-section by KPFM. Charge redistribution was observed during and after biasing, and the surface potential was seen to decay with time back to the prebias condition. This work is a first step toward directly mapping and localizing the steady-state and transient charge distribution due to point defects (traps) before, during, and after device operation, including normally inaccessible regions such as under metallization layers. Such measurements have not previously been demonstrated for GaN HEMT technology.

  8. Esimation of field-scale thermal conductivities of unsaturatedrocks from in-situ temperature data

    SciTech Connect

    Mukhopadhyay, Sumit; Tsang, Yvonne W.; Birkholzer, Jens T.

    2006-06-26

    A general approach is presented here which allows estimationof field-scale thermal properties of unsaturated rock using temperaturedata collected from in situ heater tests. The approach developed here isused to determine the thermal conductivities of the unsaturated host rockof the Drift Scale Test (DST) at Yucca Mountain, Nevada. The DST wasdesigned to obtain thermal, hydrological, mechanical, and chemical (THMC)data in the unsaturated fractured rock of Yucca Mountain. Sophisticatednumerical models have been developed to analyze these THMC data. However,though the objective of those models was to analyze "field-scale" (of theorder of tens-of-meters) THMC data, thermal conductivities measured from"laboratory-scale" core samples have been used as input parameters.While, in the absence of a better alternative, using laboratory-scalethermal conductivity values in field-scale models can be justified, suchapplications introduce uncertainties in the outcome of the models. Thetemperature data collected from the DST provides a unique opportunity toresolve some of these uncertainties. These temperature data can be usedto estimate the thermal conductivity of the DST host rock and, given thelarge volume of rock affected by heating at the DST, such an estimatewill be a more reliable effective thermal conductivity value for fieldscale application. In this paper, thus, temperature data from the DST areused to develop an estimate of the field-scale thermal conductivityvalues of the unsaturated host rock of the DST. An analytical solution isdeveloped for the temperature rise in the host rock of the DST; and usinga nonlinear fitting routine, a best-fit estimate of field-scale thermalconductivity for the DST host rock is obtained. Temperature data from theDST show evidence of two distinct thermal regimes: a zone below boiling(wet) and a zone above boiling (dry). Estimates of thermal conductivityfor both the wet and dry zones are obtained in this paper. Sensitivity ofthese estimates

  9. High Throughput In Situ EXAFS Instrumentation for the Automatic Characterization of Materials and Catalysts

    SciTech Connect

    Tsapatsaris, Nikolaos; Beesley, A. M.; Weiher, Norbert; Schroeder, Sven L. M.; Tromp, Moniek; Evans, John; Dent, A. J.; Harvey, Ian

    2007-01-19

    An XAS data acquisition and control system for the in situ analysis of dynamic materials libraries under control of temperature and gaseous environment has been developed. It was integrated at the SRS in Daresbury, UK, beamline 9.3, using a Si (220) monochromator and a 13 element solid state Ge fluorescence detector. The core of the system is an intelligent X, Y, Z, {theta} positioning system coupled to multi-stream quadrupole mass spectrometry analysis (QMS). The system is modular and can be adapted to other synchrotron radiation beamlines. The entire software control was implemented using Labview and allows the scan of a variety of library sizes, in several positions, angles, gas compositions and temperatures with minimal operator intervention. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on {gamma}-Al2O3, and for the evaluation and structural characterization of eight Au catalysts supported on Al2O3 and TiO2 Mass spectrometer traces reveal conversion rate oscillations in 6wt % Au/{gamma}Al2O3 catalysts. The use of HT experimentation for in situ EXAFS studies demonstrates the feasibility and potential of HT in situ XAFS for synchrotron radiation studies.

  10. High Throughput In Situ EXAFS Instrumentation for the Automatic Characterization of Materials and Catalysts

    NASA Astrophysics Data System (ADS)

    Tsapatsaris, Nikolaos; Beesley, A. M.; Weiher, Norbert; Tromp, Moniek; Evans, John; Dent, A. J.; Harvey, Ian; Schroeder, Sven L. M.

    2007-01-01

    An XAS data acquisition and control system for the in situ analysis of dynamic materials libraries under control of temperature and gaseous environment has been developed. It was integrated at the SRS in Daresbury, UK, beamline 9.3, using a Si (220) monochromator and a 13 element solid state Ge fluorescence detector. The core of the system is an intelligent X, Y, Z, θ positioning system coupled to multi-stream quadrupole mass spectrometry analysis (QMS). The system is modular and can be adapted to other synchrotron radiation beamlines. The entire software control was implemented using Labview and allows the scan of a variety of library sizes, in several positions, angles, gas compositions and temperatures with minimal operator intervention. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on γ-Al2O3, and for the evaluation and structural characterization of eight Au catalysts supported on Al2O3 and TiO2 Mass spectrometer traces reveal conversion rate oscillations in 6wt % Au/γAl2O3 catalysts. The use of HT experimentation for in situ EXAFS studies demonstrates the feasibility and potential of HT in situ XAFS for synchrotron radiation studies.

  11. In-situ neutron scattering studies of magnetic shape memory alloys under stress, temperature, and magnetic fields

    SciTech Connect

    Brown, Donald W; Sisneros, Thomas A; Kabra, Saurabh; Schlagel, Deborah

    2010-01-01

    We have utilized the SMARTS engineering neutron diffractometer to study the crystallographic orientation and phase transformations in the ferromagnetic shape memory alloy Ni 2MnGa under conditions of temperature (200-600K), stress (500MPa), and magnetic field (2T). Neutrons are uniquely suited to probe the crystallographic response of materials to external stimuli because of their high penetration, which allows them to sample the bulk of the material (as opposed to the surface) as well as pass through environmental chambers. A single crystal of Ni{sub 5}MnGa was repeatedly thermally cycled through the Austenitic-Martensitic phase transformation under varying conditions of applied stress, magnetic field or both. In-situ neutron diffraction was used to quantitatively monitor the population of the crystallographic variants in the martensitic phase as a function of the external stimuli during cooling. Neutron diffraction was used to monitor variant selection in the Ferromagnetic Shape Memory Alloy Ni{sub 2}Mn Ga during austenitic to martensitic transformation under varying conditions of externally applied stress and magnetic field. Qualitatively, the results were to be expected in this simple example. The shorter and magnetically soft c-axis of the tetragonal martensitic phase aligned with the compressive stress or magnetic field. However, neutron diffraction proved useful in directly quantifying the selection of the preferred variant by external influence. For instance, by quantifying the variant selection, the neutron diffraction results made apparent that the sample 'remembered' a loading cycle following a 'reset' cycle with no external applied stress. Moreover, the power of in-situ neutron diffraction will become more apparent when applied to more complex, less understood, samples such as polycrystalline samples or composite samples.

  12. Externally controlled pressure and temperature microreactor for in situ x-ray diffraction, visual and spectroscopic reaction investigations under supercritical and subcritial conditions

    SciTech Connect

    Diefenbacher, J.; McKelvy, M.; Chizemeshya, A.V.; Wolf, G.H.

    2010-07-13

    A microreactor has been developed for in situ, spectroscopic investigations of materials and reaction processes with full external pressure and temperature control from ambient conditions to 400 C and 310 bar. The sample chamber is in direct contact with an external manifold, whereby gases, liquids or fluids can be injected and their activities controlled prior to and under investigation conditions. The microreactor employs high strength, single crystal moissanite windows which allow direct probe beam interaction with a sample to investigate in situ reaction processes and other materials properties. The relatively large volume of the cell, along with full optical accessibility and external temperature and pressure control, make this reaction cell well suited for experimental investigations involving any combination of gas, fluid, and solid interactions. The microreactor's capabilities are demonstrated through an in situ x-ray diffraction study of the conversion of a meta-serpentine sample to magnesite under high pressure and temperature. Serpentine is one of the mineral candidates for the implementation of mineral carbonation, an intriguing carbon sequestration candidate technology.

  13. Externally controlled pressure and temperature microreactor for in situ x-ray diffraction, visual and spectroscopic reaction investigations under supercritical and subcritical conditions

    SciTech Connect

    Diefenbacher, Jason; McKelvy, Michael; Chizmeshya, Andrew V.G.; Wolf, George H.

    2005-01-01

    A microreactor has been developed for in situ, spectroscopic investigations of materials and reaction processes with full external pressure and temperature control from ambient conditions to 400 deg. C and 310 bar. The sample chamber is in direct contact with an external manifold, whereby gases, liquids or fluids can be injected and their activities controlled prior to and under investigation conditions. The microreactor employs high strength, single crystal moissanite windows which allow direct probe beam interaction with a sample to investigate in situ reaction processes and other materials properties. The relatively large volume of the cell, along with full optical accessibility and external temperature and pressure control, make this reaction cell well suited for experimental investigations involving any combination of gas, fluid, and solid interactions. The microreactor's capabilities are demonstrated through an in situ x-ray diffraction study of the conversion of a meta-serpentine sample to magnesite under high pressure and temperature. Serpentine is one of the mineral candidates for the implementation of mineral carbonation, an intriguing carbon sequestration candidate technology.

  14. In situ high-pressure study of FeP: Implications for planetary cores

    NASA Astrophysics Data System (ADS)

    Gu, Tingting; Wu, Xiang; Qin, Shan; Dubrovinsky, Leonid

    2011-02-01

    FeP with MnP-type structure is isostructural with high-pressure FeS polymorphs (both post-troilite FeS and FeS VI), which are believed to exist in planetary cores. Due to similar PTX phase diagrams of binary Fe-P and Fe-S, phosphorus can incorporate with iron-sulfur at planetary core conditions. To understand such substitution and the high-pressure behavior of FeP, we investigate the structural stability of FeP up to 15.6 GPa and 1800 ± 200 K by combined in situ powder X-ray diffraction and Mössbauer spectroscopy. Our experimental results show that FeP remains the MnP-type structure throughout the PT range covered. Isothermal equation of state of FeP is obtained with V0 of 92.91(8) Å 3, B0 of 205(7) GPa, and B0 of 4. The shortest axis of the MnP-type FeP cell, the b-axis, is the most compressible, due to the soft edge-sharing octahedra along the b-axis. Mössbauer results show that no electronic structure changes occur up to 15.6 GPa, but indicate decreasing distortion of FeP 6 octahedron with pressure increasing. The behavior of FeP is quite different from that of FeS under high pressure and high temperature, suggesting that phosphorus will have a significant impact on stability and electronic properties of FeS within terrestrial planet cores.

  15. In Situ 13C NMR at Elevated-Pressures and -Temperatures Investigating the Conversion of CO2 to Magnesium and Calcium Carbonate Minerals

    NASA Astrophysics Data System (ADS)

    Surface, J. A.; Conradi, M. S.; Skemer, P. A.; Hayes, S. E.

    2013-12-01

    We have constructed specialized NMR hardware to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies of unmixed heterogeneous mixtures of solids, liquids, gases, and supercritical fluids. Specifically, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine efficacy of carbonate formation in various geological reservoirs. Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals. When CO2 reacts with the calcium or magnesium in a mineral or rock sample, the 13C chemical shift, linewidth, lineshape, and relaxation times change dramatically. This change can be monitored in situ and provide instantaneous and continuous characterization that maps the chemistry that is taking place. For example, on the pathway to MgCO3 formation, there are a number of phases of Mg(OH)x(H2O)y(CO3)z that are apparent via NMR spectroscopy. We will demonstrate that NMR can be used for quantitative characterization of multiple metastable mineral phases in pure forms and in mixtures. Results are confirmed via powder XRD and Raman spectroscopy of aquo- hydro- carbonato- magnesium species and calcium carbonate species. We also have monitored the 13C spectroscopy to analyze the phase of CO2 (liquid, supercritical, or gas) and its conversion into other forms, such as bicarbonate and carbonate species, providing a "window" into the in situ pH of the reacting system. Reference: 'In Situ

  16. High resolution transmission electron microscopic in-situ observations of plastic deformation of compressed nanocrystalline gold

    SciTech Connect

    Wang, Guoyong; Lian, Jianshe; Jiang, Qing; Sun, Sheng; Zhang, Tong-Yi

    2014-09-14

    Nanocrystalline (nc) metals possess extremely high strength, while their capability to deform plastically has been debated for decades. Low ductility has hitherto been considered an intrinsic behavior for most nc metals, due to the lack of five independent slip systems actively operating during deformation in each nanograin. Here we report in situ high resolution transmission electron microscopic (HRTEM) observations of deformation process of nc gold under compression, showing the excellent ductility of individual and aggregate nanograins. Compression causes permanent change in the profile of individual nanograins, which is mediated by dislocation slip and grain rotation. The high rate of grain boundary sliding and large extent of widely exited grain rotation may meet the boundary compatibility requirements during plastic deformation. The in situ HRTEM observations suggest that nc gold is not intrinsically brittle under compressive loading.

  17. Temperature-dependent structure and phase variation of nickel silicide nanowire arrays prepared by in situ silicidation

    SciTech Connect

    Liu, Hailong; She, Guangwei; Mu, Lixuan; Shi, Wensheng

    2012-12-15

    Graphical abstract: Display Omitted Highlight: ► Nickel silicides nanowire arrays prepared by a simple in situ silicidation method. ► Phases of nickel silicides could be varied by tuning the reaction temperature. ► A growth model was proposed for the nickel silicides nanowires. ► Diffusion rates of Ni and Si play a critical role for the phase variation. -- Abstract: In this paper, we report an in situ silicidizing method to prepare nickel silicide nanowire arrays with varied structures and phases. The in situ reaction (silicidation) between Si and NiCl{sub 2} led to conversion of Si nanowires to nickel silicide nanowires. Structures and phases of the obtained nickel silicides could be varied by changing the reaction temperature. At a relatively lower temperature of 700 °C, the products are Si/NiSi core/shell nanowires or NiSi nanowires, depending on the concentration of NiCl{sub 2} solution. At a higher temperature (800 °C and 900 °C), other phases of the nickel silicides, including Ni{sub 2}Si, Ni{sub 31}Si{sub 12}, and NiSi{sub 2}, were obtained. It is proposed that the different diffusion rates of Ni and Si atoms at different temperatures played a critical role in the formation of nickel silicide nanowires with different phases.

  18. In-situ neutron diffraction study of cathode/electrolyte interactions under electrical load and elevated temperature

    NASA Astrophysics Data System (ADS)

    Tonus, F.; Skinner, S. J.

    2016-05-01

    Fuel cells are proposed as a future energy conversion technology that will reduce greenhouse gas emissions at the point of operation due to their ability to produce electrical energy from non-hydrocarbon fuel sources. The Solid Oxide Fuel Cell (SOFC) is amongst the most efficient fuel cell types, however, due to the high cell operating temperature cation diffusion occurs between the different components of the cell, resulting in rapid degradation of the power output. In this paper we investigate cation migration between the promising intermediate temperature-SOFC cathode La1-xSrxCo1-yFeyO3-δ (LSCF) and a fluorite type electrolyte Ce1-xPrxO2-δ (CPO). The crystallographic structure evolution and degradation of the materials were studied by neutron diffraction in-situ under pseudo-operating conditions, i.e. at 600 °C under air and under electrical polarisation. The lattice parameter and cation occupancy evolution were analysed by Rietveld refinement as a function of time and applied potential. The materials were found to be stable, as no impurity formation, lattice parameter or site occupancy evolution was observed during the experiment. However La migration prior to the experiment from LSCF to CPO was observed as well as B-site vacancies in LSCF.

  19. Temperature monitoring along the Rhine River based on airborne thermal infrared remote sensing: qualitative results compared to satellite data and validation with in situ measurements

    NASA Astrophysics Data System (ADS)

    Fricke, Katharina; Baschek, Björn

    2014-10-01

    Water temperature is an important parameter of water quality and influences other physical and chemical parameters. It also directly influences the survival and growth of animal and plant species in river ecosystems. In situ measurements do not allow for a total spatial coverage of water bodies and rivers that is necessary for monitoring and research at the Federal Institute of Hydrology (BfG), Germany. Hence, the ability of different remote sensing products to identify and investigate water inflows and water temperatures in Federal waterways is evaluated within the research project 'Remote sensing of water surface temperature'. The research area for a case study is the Upper and Middle Rhine River from the barrage in Iffezheim to Koblenz. Satellite products (e. g. Landsat and ASTER imagery) can only be used for rivers at least twice as wide as the spatial resolution of the satellite images. They can help to identify different water bodies only at tributaries with larger inflow volume (Main and Mosel) or larger temperature differences between the inflow (e. g. from power plants working with high capacity) and the river water. To identify and investigate also smaller water inflows and temperature differences, thermal data with better ground and thermal resolution is required. An aerial survey of the research area was conducted in late October 2013. Data of the surface was acquired with two camera systems, a digital camera with R, G, B, and Near-IR channels, and a thermal imaging camera measuring the brightness temperature in the 8-12 m wavelength region (TIR). The resolution of the TIR camera allowed for a ground resolution of 4 m, covering the whole width of the main stream and larger branches. The RGB and NIR data allowed to eliminate land surface temperatures from the analysis and to identify clouds and shadows present during the data acquisition. By degrading the spatial resolution and adding sensor noise, artificial Landsat ETM+ and TIRS datasets were created

  20. High temperature furnace

    DOEpatents

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  1. High Conductivity, High Strength Solid Electrolytes Formed by in Situ Encapsulation of Ionic Liquids in Nanofibrillar Methyl Cellulose Networks.

    PubMed

    Mantravadi, Ramya; Chinnam, Parameswara Rao; Dikin, Dmitriy A; Wunder, Stephanie L

    2016-06-01

    Strong, solid polymer electrolyte ion gels, with moduli in the MPa range, a capacitance of 2 μF/cm(2), and high ambient ionic conductivities (>1 × 10(-3) S/cm), all at room temperature, have been prepared from butyl-N-methyl pyrrolidinium bis(trifluoromethylsulfonyl) imide (PYR14TFSI) and methyl cellulose (MC). These properties are particularly attractive for supercapacitor applications. The ion gels are prepared by codissolution of PYR14TFSI and MC in N,N-dimethylformamide (DMF), which after heating and subsequent cooling form a gel. Evaporation of DMF leave thin, flexible, self-standing ion gels with up to 97 wt % PYR14TFSI, which have the highest combined moduli and ionic conductivity of ion gels to date, with an excellent electrochemical stability window (5.6 V). These favorable properties are attributed to the immiscibility of PYR14TFSI in MC, which permits the ionic conductivity to be independent of the MC at low MC content, and the in situ formation of a volume spanning network of semicrystalline MC nanofibers, which have a high glass transition temperature (Tg = 190 °C) and remain crystalline until they degrade at 300 °C. PMID:27153318

  2. Biogeochemistry of Hydrothermal Chimney Environments: Continuous-Flow Experiments at in situ Temperature and Pressure

    NASA Astrophysics Data System (ADS)

    Houghton, J.; Seyfried, W.; Reysenbach, A.; Banta, A.; von Damm, K.

    2002-12-01

    Recent interest in the existence of a subsurface microbial biosphere at hydrothermal vents has resulted in a plethora of new questions that might best be answered using interdisciplinary techniques that combine geochemistry, microbial ecology, and molecular biology. Ideally, such studies will quantitatively address issues concerning what organisms exist in the subsurface, what metabolisms are sustained in the hydrothermal environment, and what effects these active organisms might have on the nearby fluid and rock. We present a new experimental approach to studying these questions that enables monitoring of an active hydrothermal community of microbes in the presence of chimney material at in situ temperature and pressure. This apparatus is designed as a continuous-flow reactor from which fluid samples can be extracted during the course of the experiment to measure chemistry and biomass, and at the termination of an experiment solids can be extracted for analysis of mineralogical changes and microbial identification. Results of a series of experiments conducted using hydrothermal chimney material (solids and microbial community) collected from 21° N and 9° N East Pacific Rise are presented. At 70° C, a seawater-based fluid with additional NO3-, CO2(aq), and H2(aq) was reacted with chimney material from L vent, 9° N EPR. The fluid lost significant NO3-, PO43-, and gained SO42- even after accounting for the contribution from anhydrite dissolution. No significant sulfide or iron was observed in the fluid. Analysis of the DNA extracted from the solids at the termination of the experiment using partial 16S-rRNA sequence data revealed that the dominant bacteria were S-oxidizing tube worm endosymbionts, a S/NO3- reducing member of the Deferribacter genus, and a H2-oxidizing/NO3- reducing strain of Aquifex. Mineral analysis from before and after the experiment indicates the loss of pyrrhotite (FeS) and anhydrite (CaSO4), and the gain of an Fe-oxide phase tentatively

  3. In-situ Studies of Highly Charged Ions at the LLNL EBIT

    SciTech Connect

    Beiersdorfer, P

    2001-08-16

    The properties of highly charged ions and their interaction with electrons and atoms is being studied in-situ at the LLNL electron beam ion traps, EBIT-II and SuperEBIT. Spectroscopic measurements provide data on electron-ion and ion-atom interactions as well as accurate transition energies of lines relevant for understanding QED, nuclear magnetization, and the effects of relativity on complex, state-of-the-art atomic calculations.

  4. Initial characterization of a highly contaminated high explosives outfall in preparation for in situ bioremediation

    SciTech Connect

    Betty A. Strietelmeier; Patrick J. Coyne; Patricia A. Leonard; W. Lamar Miller; Jerry R. Brian

    1999-12-01

    In situ bioremediation is a viable, cost-effective treatment for environmental contamination of many kinds. The feasibility of using biological techniques to remediate soils contaminated with high explosives (HE) requires laboratory evaluation before proceeding to a larger scale field operation. Laboratory investigations have been conducted at pilot scale which indicate that an anaerobic process could be successful at reducing levels of HE, primarily HMX, RDX and TNT, in contaminated soils. A field demonstration project has been designed to create an anaerobic environment for the degradation of HE materials. The first step in this project, initial characterization of the test area, was conducted and is the subject of this report. The levels of HE compounds found in the samples from the test area were higher than the EPA Method 8330 was able to extract without subsequent re-precipitation; therefore, a new method was developed using a superior extractant system. The test area sampling design was relatively simple as one might expect in an initial characterization. A total of 60 samples were each removed to a depth of 4 inches using a 1 inch diameter corer. The samples were spaced at relatively even intervals across a 20 foot cross-section through the middle of four 7-foot-long adjacent plots which are designed to be a part of an in situ bioremediation experiment. Duplicate cores were taken from each location for HE extraction and analysis in order to demonstrate and measure the heterogeneity of the contamination. Each soil sample was air dried and ball-milled to provide a homogeneous solid for extraction and analysis. Several samples had large consolidated pieces of what appeared to be solid HE. These were not ball-milled due to safety concerns, but were dissolved and the solutions were analyzed. The new extraction method was superior in that results obtained for several of the contaminants were up to 20 times those obtained with the EPA extraction method. The

  5. The difference between laboratory and in-situ pixel-averaged emissivity: The effects on temperature-emissivity separation

    NASA Technical Reports Server (NTRS)

    Matsunaga, Tsuneo

    1993-01-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a Japanese future imaging sensor which has five channels in thermal infrared (TIR) region. To extract spectral emissivity information from ASTER and/or TIMS data, various temperature-emissivity (T-E) separation methods have been developed to date. Most of them require assumptions on surface emissivity, in which emissivity measured in a laboratory is often used instead of in-situ pixel-averaged emissivity. But if these two emissivities are different, accuracies of separated emissivity and surface temperature are reduced. In this study, the difference between laboratory and in-situ pixel-averaged emissivity and its effect on T-E separation are discussed. TIMS data of an area containing both rocks and vegetation were also processed to retrieve emissivity spectra using two T-E separation methods.

  6. Fitting of satellite and in-situ ocean surface temperatures Results for polymode during the winter of 1977-1978

    NASA Technical Reports Server (NTRS)

    Maul, G. A.; Bravo, N. J.

    1983-01-01

    For the period considered, December 1977 through February 1978, bivariate Gaussian discriminant function cloud identification revealed that more than 93 percent of the 8-km resolution GOES infrared pixels were cloud contaminated. Cloud-free in-situ calibration points were distributed in nonrandom groups; this resulted in systematic errors when using least squares techniques. Surfaces and regression lines were least squares fitted between satellite and in-situ data; use was also made of differences and ratios. The best results were achieved with a regression in the form of the infrared radiative transfer equation; but this was no better than + or - 0.9 K. Because of extensive cloudiness, the linear regressions were seldom useful, and temperature ratios with + or - 1.3 K experimental errors best represent the applicability of GEOS data to sea surface temperatures.

  7. In situ, high-resolution imaging of labile phosphorus in sediments of a large eutrophic lake.

    PubMed

    Ding, Shiming; Han, Chao; Wang, Yanping; Yao, Lei; Wang, Yan; Xu, Di; Sun, Qin; Williams, Paul N; Zhang, Chaosheng

    2015-05-01

    Understanding the labile status of phosphorus (P) in sediments is crucial for managing a eutrophic lake, but it is hindered by lacking in situ data particularly on a catchment scale. In this study, we for the first time characterized in situ labile P in sediments with the Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique at a two-dimensional (2D), submillimeter resolution in a large eutrophic lake (Lake Taihu, China, with an area of 2338 km(2)). The concentration of DGT-labile P in the sediment profiles showed strong variation mostly ranging from 0.01 to 0.35 mg L(-1) with a considerable number of hotspots. The horizontal heterogeneity index of labile P varied from 0.04 to 4.5. High values appeared at the depths of 0-30 mm, likely reflecting an active layer of labile P under the sediment-water interface (SWI). Concentration gradients of labile P were observed from the high-resolution 1D DGT profiles in both the sediment and overlying water layers close to the SWI. The apparent diffusion flux of P across the SWI was calculated between -21 and 65 ng cm(-2) d(-1), which showed that the sediments tended to be a source and sink of overlying water P in the algal- and macrophyte-dominated regions, respectively. The DGT-labile P in the 0-30 mm active layer showed a better correlation with overlying water P than the labile P measured by ex situ chemical extraction methods. It implies that in situ, high-resolution profiling of labile P with DGT is a more reliable approach and will significantly extend our ability in in situ monitoring of the labile status of P in sediments in the field. PMID:25720671

  8. Mineralogical determination in situ of a highly heterogeneous material using a miniaturized laser ablation mass spectrometer with high spatial resolution

    NASA Astrophysics Data System (ADS)

    Neubeck, Anna; Tulej, Marek; Ivarsson, Magnus; Broman, Curt; Riedo, Andreas; McMahon, Sean; Wurz, Peter; Bengtson, Stefan

    2016-04-01

    Techniques enabling in situ elemental and mineralogical analysis on extraterrestrial planets are strongly required for upcoming missions and are being continuously developed. There is ample need for quantitative and high-sensitivity analysis of elemental as well as isotopic composition of heterogeneous materials. Here we present in situ spatial and depth elemental profiles of a heterogeneous rock sample on a depth-scale of nanometres using a miniaturized laser ablation mass spectrometer (LMS) designed for planetary space missions. We show that the LMS spectra alone could provide highly detailed compositional, three-dimensional information and oxidation properties of a natural, heterogeneous rock sample. We also show that a combination of the LMS and Raman spectroscopy provide comprehensive mineralogical details of the investigated sample. These findings are of great importance for future space missions where quick, in situ determination of the mineralogy could play a role in the process of selecting a suitable spot for drilling.

  9. In situ formation and assembly of CdS nanocrystallites into polyhedrons on Eggshell membrane at room temperature

    NASA Astrophysics Data System (ADS)

    Su, Huilan; Xu, Jia; Chen, Jianjun; Moon, Won-Jin; Zhang, Di

    2012-01-01

    A room-temperature soakage procedure was carried out to successfully form and assemble CdS nanocrystallites into polyhedrons on the eggshell membrane (ESM). Based on the biomaterial ESM served as the reactive substrate and some ESM biomacromolecules acted as the surfactants, CdS nanocrystallites were in situ formed, further assembled into well-distributed polyhedrons, and finally performed CdS-ESM hybrid nanocomposites. This moderate bioinspired strategy would also be of great value to prepare novel functional nanocomposites.

  10. In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus

    NASA Astrophysics Data System (ADS)

    Kuhn, Thomas; Heymsfield, Andrew J.

    2016-06-01

    Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time, these clouds absorb the infrared radiation from the Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions and particle shapes. Knowledge of these cloud properties is also needed for calibrating and validating passive and active remote sensors. Ice particles of sizes below 100 µm are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. Furthermore, artefacts are produced by shattering of particles on the leading surfaces of the aircraft probes when particles several hundred microns or larger are present. Here, we report on a series of balloon-borne in situ measurements that were carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The method used here avoids these issues experienced with the aircraft probes. Furthermore, with a balloon-borne instrument, data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s-1. The collecting film is advanced uniformly inside the instrument so that an always unused section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 µm together with a pixel resolution of 1.65 µm allows particle detection at sizes of 10 µm and larger. For particles that are 20 µm (12 pixel) in size or larger, the shape can be recognized. The sampling volume, 130 cm3 s-1, is well defined and independent of particle size. With the encountered number concentrations of between 4 and 400 L-1, this required about 90- to 4-s sampling times to

  11. Two-step in situ biodiesel production from microalgae with high free fatty acid content.

    PubMed

    Dong, Tao; Wang, Jun; Miao, Chao; Zheng, Yubin; Chen, Shulin

    2013-05-01

    The yield of fatty acid methyl ester (FAME) from microalgae biomass is generally low via traditional extraction-conversion route due to the deficient solvent extraction. In this study a two-step in situ process was investigated to obtain a high FAME yield from microalgae biomass that had high free fatty acids (FFA) content. This was accomplished with a pre-esterification process using heterogeneous catalyst to reduce FFA content prior to the base-catalyzed transesterification. The two-step in situ process resulted in a total FAME recovery up to 94.87±0.86%, which was much higher than that obtained by a one-step acid or base catalytic in situ process. The heterogeneous catalyst, Amberlyst-15, could be used for 8 cycles without significant loss in activity. This process have the potential to reduce the production cost of microalgae-derived FAME and be more environmental compatible due to the higher FAME yield with reduced catalyst consumption. PMID:23548399

  12. A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

    USGS Publications Warehouse

    Sharma, Sapna; Gray, Derek; Read, Jordan S.; O'Reilly, Catherine; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie; Hook, Simon; Lenters, John; Livingstone, David M.; McIntyre, Peter B.; Adrian, Rita; Allan, Mathew; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John E.; Baron, Jill S.; Brookes, Justin D; Chen, Yuwei; Daly, Robert; Ewing, Kye; de Eyto, Elvira; Dokulil, Martin; Hamilton, David B.; Havens, Karl; Haydon, Shane; Hetzenaeur, Harald; Heneberry, Jocelyn; Hetherington, Amy; Higgins, Scott; Hixson, Eric; Izmest'eva, Lyubov; Jones, Benjamin M.; Kangur, Kulli; Kasprzak, Peter; Kraemer, Benjamin; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Dörthe Müller-Navarra; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Pius Niederhauser; North, Ryan P.; Andrew Paterson; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Lars Rudstam; Rusak, James A.; Salmaso, Nico; Samal, Nihar R.; Daniel E. Schindler; Geoffrey Schladow; Schmidt, Silke R.; Tracey Schultz; Silow, Eugene A.; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A.; Craig E. Williamson; Kara H. Woo

    2015-01-01

    Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

  13. A global database of lake surface temperatures collected by in situ and satellite methods from 1985-2009.

    PubMed

    Sharma, Sapna; Gray, Derek K; Read, Jordan S; O'Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest'eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

    2015-01-01

    Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985-2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues. PMID:25977814

  14. A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

    PubMed Central

    Sharma, Sapna; Gray, Derek K; Read, Jordan S; O’Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest’eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

    2015-01-01

    Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues. PMID:25977814

  15. In-situ optical monitoring of AlAs wet oxidation using a novel low-temperature low-pressure steam furnace design

    SciTech Connect

    Feld, S.A.; Loehr, J.P.; Sherriff, R.E.; Wiemeri, J.; Kaspi, R.

    1998-02-01

    To reproducibly define small features by oxidizing AlGaAs layers, it is essential to have good control over the oxidation reaction. The authors have integrated a glass viewport into a low-pressure (5 torr) cold-walled oxidation chamber to enable in situ optical monitoring of the sample during oxidation. To gain additional control, they reduced the oxidation temperature to 325 C, consequently slowing the oxidation rate to 2 {micro}m/h. Real-time in situ optical measurements of AlAs oxidation rates were performed using this system and the results were compared with a standard model. Oxide-semiconductor distributed Bragg reflectors (DBRs) were also fabricated and measured, yielding highly reflective mirrors suitable for vertical-cavity surface-emitting laser (VCSEL) fabrication.

  16. In situ transmission infrared spectroscopy of high-kappa oxide atomic layer deposition onto silicon surfaces

    NASA Astrophysics Data System (ADS)

    Ho, Ming-Tsung

    Ultra-thin aluminum oxide (Al2O3) and hafnium oxide (HfO2) layers have been grown by atomic layer deposition (ALD) using tri-methyl-aluminum (TMA) and tetrakis-ethyl-methyl-amino-hafnium (TEMAH) respectively with heavy water (D2O) as the oxidizing agent. Several different silicon surfaces were used as substrates such as hydrogen terminated silicon (H/Si), SC2 (or RCA 2) cleaned native silicon oxide (SiO 2/Si), and silicon (oxy)nitride. In-situ transmission Fourier transform infrared spectroscopy (FTIR) has been adopted for the study of the growth mechanisms during ALD of these films. The vibrational spectra of gas phase TEMAH and its reaction byproducts with oxidants have also been investigated. Density functional theory (DFT) normal mode calculations show a good agreement with the experimental data when it is combined with linear wave-number scaling method and Fermi resonance mechanism. Ether (-C-O-C-) and tertiary alkylamine (N(R1R 2R3)) compounds are the two most dominant products of TEMAH reacting with oxygen gas and water. When ozone is used as the oxidant, gas phase CH2O, CH3NO2, CH3-N=C=O and other compounds containing -(C=O)- and --C-O-C- (or --O-C-) segments are observed. With substrate temperatures less than 400°C and 300°C for TMA and TEMAH respectively, Al oxide and Hf oxide ALD can be appropriately performed on silicon surfaces. Thin silicon (oxy)nitride thermally grown in ammonia on silicon substrate can significantly reduce silicon oxide interlayer formation during ALD and post-deposition annealing. The crystallization temperature of amorphous ALD grown HfO2 on nitridized silicon is 600°C, which is 100°C higher than on the other silicon surfaces. When HfO2 is grown on H/Si(111) at 100°C deposition temperature, minimum 5--10 ALD cycles are required for the full surface coverage. The steric effect can be seen by the evolution of the H-Si stretching mode at 2083 cm-1. The observed red shift of H-Si stretching to ˜ 2060 cm-1 can be caused by Si

  17. Calibrating IR Cameras for In-Situ Temperature Measurement During the Electron Beam Melting Process using Inconel 718 and Ti-Al6-V4

    SciTech Connect

    Dinwiddie, Ralph Barton; Lloyd, Peter D; Dehoff, Ryan R; Lowe, Larry E

    2016-01-01

    The Department of Energy s (DOE) Manufacturing Demonstration Facility (MDF) at Oak Ridge National Laboratory (ORNL) provides world-leading capabilities in advanced manufacturing (AM) facilities which leverage previous, on-going government investments in materials science research and characterization. MDF contains systems for fabricating components with complex geometries using AM techniques (i.e. 3D-Printing). Various metal alloy printers, for example, use electron beam melting (EBM) systems for creating these components which are otherwise extremely difficult- if not impossible- to machine. ORNL has partnered with manufacturers on improving the final part quality of components and developing new materials for further advancing these devices. One method being used to study (AM) processes in more depth relies on the advanced imaging capabilities at ORNL. High performance mid-wave infrared (IR) cameras are used for in-situ process monitoring and temperature measurements. However, standard factory calibrations are insufficient due to very low transmissions of the leaded glass window required for X-ray absorption. Two techniques for temperature calibrations will be presented and compared. In-situ measurement of emittance will also be discussed. Ample information can be learned from in-situ IR process monitoring of the EBM process. Ultimately, these imaging systems have the potential for routine use for online quality assurance and feedback control.

  18. Quantitative comparison of airborne remote-sensed and in situ Rhodamine WT dye and temperature during RIVET & IB09

    NASA Astrophysics Data System (ADS)

    Lenain, L.; Clark, D. B.; Guza, R. T.; Hally-Rosendahl, K.; Statom, N.; Feddersen, F.

    2012-12-01

    The transport and evolution of temperature, sediment, chlorophyll, fluorescent dye, and other tracers is of significant oceanographic interest, particularly in complex coastal environments such as the nearshore, river mouths, and tidal inlets. Remote sensing improves spatial coverage over in situ observations, and ground truthing remote sensed observations is critical for its use. Here, we present remotely sensed observations of Rhodamine WT dye and Sea Surface Temperature (SST) using the SIO Modular Aerial Sensing System (MASS) and compare them with in situ observations from the IB09 (0-300 m seaward of the surfzone, Imperial Beach, CA, October 2009) and RIVET (New River Inlet, NC, May 2012) field experiments. Dye concentrations are estimated from a unique multispectral camera system that measures the emission and absorption wavelengths of Rhodamine WT dye. During RIVET, dye is also characterized using a pushbroom hyperspectral imaging system (SPECIM AISAEagle VNIR 400-990 nm) while SST is estimated using a long-wave infrared camera (FLIR SC6000HS) coupled with an infrared pyrometer (Heitronics KT19.85II). Repeated flight passes over the dye plume were conducted approximately every 5 min for up to 4.5 hr in duration with a swath width ranging from 400 to 2000 m (altitude dependent), and provided a unique spatio-temporal depiction of the plume. A dye proxy is developed using the measured radiance at the emission and absorption wavelengths of the Rhodamine WT dye. During IB09 and RIVET, in situ dye and temperature were measured with two GPS-tracked jet skis, a small boat, and moored observations. The in situ observations are compared with the remotely sensed data in these two complex coastal environments. Funding was provided by the Office of Naval Research.

  19. In situ growth of monolayer porous gold nanoparticles film as high-performance SERS substrates

    NASA Astrophysics Data System (ADS)

    Song, Chunyuan; Wei, Yuhan; Da, Bingtao; Zhang, Haiting; Cong, Xing; Yang, Boyue; Yang, Yanjun; Wang, Lianhui

    2016-07-01

    Surface-enhanced Raman scattering (SERS) has recently received considerable attention as an ultrasensitive analytic technique. However, its wide application is limited by lack of excellent SERS-active substrates. In this work a SERS substrate with arrayed monolayer films of porous gold nanoparticles is prepared on a solid substrate by a facile, in situ and one-step growth approach. Specifically, the solid substrate was coated with a layer of dense positive charges first by layer-by-layer assembly, followed by patterned a PDMS film with arrayed wells on the substrate. Then the growth solution including chlorauric acid, cetyltrimethylammonium chloride, and ascorbic acid in a certain proportion was transferred into the wells for in situ and one-step growth of porous gold nanoparticles on the substrate. The growth time, feed ratio of the reagents, and repeat times of the in situ growth were studied systematically to obtain optimal parameters for preparing an optimal SERS substrate. The as-prepared optimal SERS substrate not only has good SERS performance with the enhancement factor up to ∼1.10 × 106, but also shows good uniformity and stability. The SERS substrate was further utilized to be ultrasensitive SERS-based chemical sensors for ppb-level detection of highly toxic dyfonate. The preliminary result indicates that the as-prepared SERS substrate has good SERS performance and shows a number of great potential applications in SERS-based sensors.

  20. In-situ Production of High Density Polyethylene and Other Useful Materials on Mars

    NASA Technical Reports Server (NTRS)

    Flynn, Michael

    2005-01-01

    This paper describes a revolutionary materials structure and power storage concept based on the in-situ production of abiotic carbon 4 compounds. One of the largest single mass penalties required to support the human exploration of Mars is the surface habitat. This proposal will use physical chemical technologies to produce high density polyethylene (HDPE) inflatable structures and construction materials from Mars atmospheric CO2. The formation of polyethylene from Mars CO2 is based on the use of the Sabatier and modified Fischer Tropsch reactions. The proposed system will fully integrate with existing in-situ propellant production concepts. The technology will also be capable of supplementing human caloric requirements, providing solid and liquid fuels for energy storage, and providing significant reduction in mission risk. The NASA Mars Reference Mission Definition Team estimated that a conventional Mars surface habitat structure would weigh 10 tonnes. It is estimated that this technology could reduce this mass by 80%. This reduction in mass will significantly contribute to the reduction in total mission cost need to make a Mars mission a reality. In addition the potential reduction of risk provided by the ability to produce C4 and potentially higher carbon based materials in-situ on Mars is significant. Food, fuel, and shelter are only three of many requirements that would be impacted by this research.

  1. In situ Rheological Measurements at Extreme Pressure and Temperature using Synchrotron X-ray Diffraction and Radiography

    SciTech Connect

    Raterron, P.; Merkel, S

    2009-01-01

    Dramatic technical progress seen over the past decade now allows the plastic properties of materials to be investigated under extreme pressure and temperature conditions. Coupling of high-pressure apparatuses with synchrotron radiation significantly improves the quantification of differential stress and specimen textures from X-ray diffraction data, as well as specimen strains and strain rates by radiography. This contribution briefly reviews the recent developments in the field and describes state-of-the-art extreme-pressure deformation devices and analytical techniques available today. The focus here is on apparatuses promoting deformation at pressures largely in excess of 3 GPa, namely the diamond anvil cell, the deformation-DIA apparatus and the rotational Drickamer apparatus, as well as on the methods used to carry out controlled deformation experiments while quantifying X-ray data in terms of materials rheological parameters. It is shown that these new techniques open the new field of in situ investigation of materials rheology at extreme conditions, which already finds multiple fundamental applications in the understanding of the dynamics of Earth-like planet interior.

  2. High temperature sensor

    DOEpatents

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  3. In Situ Observations of Thermoreversible Gelation and Phase Separation of Agarose and Methylcellulose Solutions under High Pressure.

    PubMed

    Kometani, Noritsugu; Tanabe, Masahiro; Su, Lei; Yang, Kun; Nishinari, Katsuyoshi

    2015-06-01

    Thermoreversible sol-gel transitions of agarose and methylcellulose (MC) aqueous solutions on isobaric cooling or heating under high pressure up to 400 MPa have been investigated by in situ observations of optical transmittance and falling-ball experiments. For agarose, which undergoes the gelation on cooling, the application of pressure caused a gradual rise in the cloud-point temperature over the whole pressure range examined, which is almost consistent with the pressure dependence of gelling temperature estimated by falling-ball experiments, suggesting that agarose gel is stabilized by compression and that the gelation occurs nearly in parallel with phase separation under ambient and high-pressure conditions. For MC, which undergoes the gelation on heating, the cloud-point temperature showed a slight rise with an initial elevation of pressure up to ∼150 MPa, whereas it showed a marked depression above 200 MPa. In contrast, the gelling temperature of MC, which is nearly identical to the cloud-point temperature at ambient pressure, showed a monotonous rise with increasing pressure up to 350 MPa, which means that MC undergoes phase separation prior to gelation on heating under high pressure above 200 MPa. Similar results were obtained for the melting process of MC gel on cooling. The unique behavior of the sol-gel transition of MC under high pressure has been interpreted in terms of the destruction of hydrophobic hydration by compression. PMID:25984597

  4. A generalized method for high throughput in-situ experiment data analysis: An example of battery materials exploration

    NASA Astrophysics Data System (ADS)

    Aoun, Bachir; Yu, Cun; Fan, Longlong; Chen, Zonghai; Amine, Khalil; Ren, Yang

    2015-04-01

    A generalized method is introduced to extract critical information from series of ranked correlated data. The method is generally applicable to all types of spectra evolving as a function of any arbitrary parameter. This approach is based on correlation functions and statistical scedasticity formalism. Numerous challenges in analyzing high throughput experimental data can be tackled using the herein proposed method. We applied this method to understand the reactivity pathway and formation mechanism of a Li-ion battery cathode material during high temperature synthesis using in-situ high-energy X-ray diffraction. We demonstrate that Pearson's correlation function can easily unravel all major phase transition and, more importantly, the minor structural changes which cannot be revealed by conventionally inspecting the series of diffraction patterns. Furthermore, a two-dimensional (2D) reactivity pattern calculated as the scedasticity along all measured reciprocal space of all successive diffraction pattern pairs unveils clearly the structural evolution path and the active areas of interest during the synthesis. The methods described here can be readily used for on-the-fly data analysis during various in-situ operando experiments in order to quickly evaluate and optimize experimental conditions, as well as for post data analysis and large data mining where considerable amount of data hinders the feasibility of the investigation through point-by-point inspection.

  5. In situ gas analysis for high pressure applications using property measurements

    NASA Astrophysics Data System (ADS)

    Moeller, J.; Span, R.; Fieback, T.

    2013-10-01

    As the production, distribution, and storage of renewable energy based fuels usually are performed under high pressures and as there is a lack of in situ high pressure gas analysis instruments on the market, the aim of this work was to develop a method for in situ high pressure gas analysis of biogas and hydrogen containing gas mixtures. The analysis is based on in situ measurements of optical, thermo physical, and electromagnetic properties in gas mixtures with newly developed high pressure sensors. This article depicts the calculation of compositions from the measured properties, which is carried out iteratively by using highly accurate equations of state for gas mixtures. The validation of the method consisted of the generation and measurement of several mixtures, of which three are presented herein: a first mixture of 64.9 mol. % methane, 17.1 mol. % carbon dioxide, 9 mol. % helium, and 9 mol. % ethane at 323 K and 423 K in a pressure range from 2.5 MPa to 17 MPa; a second mixture of 93.0 mol. % methane, 4.0 mol. % propane, 2.0 mol. % carbon dioxide, and 1.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 1.2 MPa to 3 MPa; and a third mixture of 64.9 mol. % methane, 30.1 mol. % carbon dioxide, and 5.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 2.5 MPa to 4 MPa. The analysis of the tested gas mixtures showed that with measured density, velocity of sound, and relative permittivity the composition can be determined with deviations below 1.9 mol. %, in most cases even below 1 mol. %. Comparing the calculated compositions with the generated gas mixture, the deviations were in the range of the combined uncertainty of measurement and property models.

  6. Highly indistinguishable photons from deterministic quantum-dot microlenses utilizing three-dimensional in situ electron-beam lithography

    NASA Astrophysics Data System (ADS)

    Gschrey, M.; Thoma, A.; Schnauber, P.; Seifried, M.; Schmidt, R.; Wohlfeil, B.; Krüger, L.; Schulze, J.-H.; Heindel, T.; Burger, S.; Schmidt, F.; Strittmatter, A.; Rodt, S.; Reitzenstein, S.

    2015-07-01

    The success of advanced quantum communication relies crucially on non-classical light sources emitting single indistinguishable photons at high flux rates and purity. We report on deterministically fabricated microlenses with single quantum dots inside which fulfil these requirements in a flexible and robust quantum device approach. In our concept we combine cathodoluminescence spectroscopy with advanced in situ three-dimensional electron-beam lithography at cryogenic temperatures to pattern monolithic microlenses precisely aligned to pre-selected single quantum dots above a distributed Bragg reflector. We demonstrate that the resulting deterministic quantum-dot microlenses enhance the photon-extraction efficiency to (23+/-3)%. Furthermore we prove that such microlenses assure close to pure emission of triggered single photons with a high degree of photon indistinguishability up to (80+/-7)% at saturation. As a unique feature, both single-photon purity and photon indistinguishability are preserved at high excitation power and pulsed excitation, even above saturation of the quantum emitter.

  7. In-situ short circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Rouillard, Jean; Rouillard, Roger; Shiota, Toshimi; Trice, Jennifer L.

    2000-01-01

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  8. In-situ short-circuit protection system and method for high-energy electrochemical cells

    DOEpatents

    Gauthier, Michel; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Rouillard, Jean; Rouillard, Roger; Shiota, Toshimi; Trice, Jennifer L.

    2003-04-15

    An in-situ thermal management system for an energy storage device. The energy storage device includes a plurality of energy storage cells each being coupled in parallel to common positive and negative connections. Each of the energy storage cells, in accordance with the cell's technology, dimensions, and thermal/electrical properties, is configured to have a ratio of energy content-to-contact surface area such that thermal energy produced by a short-circuit in a particular cell is conducted to a cell adjacent the particular cell so as to prevent the temperature of the particular cell from exceeding a breakdown temperature. In one embodiment, a fuse is coupled in series with each of a number of energy storage cells. The fuses are activated by a current spike capacitively produced by a cell upon occurrence of a short-circuit in the cell, thereby electrically isolating the short-circuited cell from the common positive and negative connections.

  9. Laser-induced thermotherapy (LITT): energy and temperature determination for complete in-situ ablation of liver metastasis

    NASA Astrophysics Data System (ADS)

    Isbert, Christoph M.; Roggan, Andre; Ritz, Joerg-Peter; Mueller, Gerhard J.; Buhr, Heinz-Johannes; Lehmann, Kai-S.; Germer, Christoph-Thomas

    2000-11-01

    Purpose: The aim of this study was to determine the energy (J/mm3 tumor volume) and temperature required for a complete in-situ-ablation of experimental liver tumors. Methods: LITT was performed in VX-2 tumor-bearing rabbits using Nd-YAG-Laser (1064 nm) with a diffuser-tip applicator and a temperature feedback-system. The animals were randomized into 4 groups (n equals 20) that differed in the target temperature at the tumor border [45 degrees Celsius, 50 degrees Celsius, 55 degrees Celsius and 60 degrees Celsius]. Histological examination was done at 0 h, 24 h, 96 h and 14 days after LITT. Results: The pretreatment tumor volume of 2191 +/- 61 mm3 was the same for all groups (p > 0.05). Energy and temperature required and the rate of incomplete tumor-ablation (recurrences) are listed below (* equals p < 0.05, Kruskal-Wallis test. Conclusions: (1) To achieve complete in-situ-ablation under the given conditions, it is necessary to apply laser-energy of 3 J/mm3 tumor volume. (2) A minimum temperature of 60 degrees Celsius on the tumor border presumed an application of 10 minutes.

  10. Comparison of in-situ, aircraft, and satellite based land surface temperature measurements over a mixed agricultural region

    NASA Astrophysics Data System (ADS)

    Krishnan, P.; Baker, B.; Kochendorfer, J.; Dumas, E.; Meyers, T. P.; Guillevic, P. C.; Corda, S.; Muratore, J. F.; Simmons, D.

    2013-12-01

    Land surface temperature (LST) is a key variable in the study of the exchange of energy and water between the land surface and the atmosphere, and it influences land surface physical processes at regional and global scales. With the objective of quantifying the spatial variability and overall representativeness of single-point surface temperature measurements and to improve the accuracy of satellite LST measurements, airborne campaigns were conducted over a mixed agricultural area near Bondville, Illinois during 2012 and 2013. During the campaigns, multiple measurements of surface temperature were made using infra-red temperature sensors at micrometeorological tower sites, which include NOAA's Climate Reference Network (CRN) and nearby flux tower sites, and onboard an instrumented Piper Navajo airborne research aircraft. In addition to this, daily LST products from the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard the NASA Terra and Aqua Earth Observing System satellites were used. The aircraft-based and satellite-based LST measurements were compared with the in situ, tower-based LST measurements. Observations indicate large spatial and temporal variability of land surface temperature over the Bondville area. Our results show good agreement between in situ, aircraft and satellite measurements. The agreement was better with the LST data from the flux tower than those from CRN tower.

  11. Mineral Carbonation in Wet Supercritical CO2: An in situ High-Pressure Magic Angle Spinning Nuclear Magnetic Resonance Study

    NASA Astrophysics Data System (ADS)

    Turcu, R. V.; Hoyt, D. H.; Sears, J. A.; Rosso, K. M.; Felmy, A. R.; Hu, J. Z.

    2011-12-01

    Understanding the mechanisms and kinetics of mineral carbonation reactions relevant to sequestering carbon dioxide as a supercritical fluid (scCO2) in geologic formations is crucial for accurately predicting long-term storage risks. In situ probes that provide molecular-level information at geologically relevant temperatures and pressures are highly desirable and challenging to develop. Magic angle spinning nuclear magnetic resonance (MAS NMR) is a powerful tool for obtaining detailed molecular structure and dynamics information of a system regardless whether the system is in a solid, a liquid, a gaseous, a supercritical state, or a mixture thereof. However, MAS NMR under scCO2 conditions has never been realized due to the tremendous technical difficulties of achieving and maintaining high pressure within a fast spinning MAS sample rotor. In this work, we report development of a unique high pressure MAS NMR capability capable of handling fluid pressure exceeding 170 bars and temperatures up to 80°C, and its application to mineral carbonation in scCO2 under geologically relevant temperatures and pressures. Mineral carbonation reactions of the magnesium silicate mineral forsterite and the magnesium hydroxide brucite reacted with scCO2 (up to 170 bar) and containing variable content of H2O (at, below, and above saturation in scCO2) were investigated at 50 to 70°C. In situ 13C MAS NMR spectra show peaks corresponding to the reactants, intermediates, and the magnesium carbonation products in a single spectrum. For example, Figure 1 shows the reaction dynamics, i.e., the formation and conversion of reaction intermediates, i.e., HCO3- and nesquehonite, to magnesite as a function of time at 70°C. This capability offers a significant advantage over traditional ex situ 13C MAS experiments on similar systems, where, for example, CO2 and HCO3- are not directly observable.

  12. High temperature refrigerator

    DOEpatents

    Steyert, Jr., William A.

    1978-01-01

    A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

  13. High-Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  14. New developments in laser-heated diamond anvil cell with in situ synchrotron x-ray diffraction at High Pressure Collaborative Access Team

    SciTech Connect

    Meng, Yue; Hrubiak, Rostislav; Rod, Eric; Shen, Guoyin; Boehler, Reinhard

    2015-07-15

    An overview of the in situ laser heating system at the High Pressure Collaborative Access Team, with emphasis on newly developed capabilities, is presented. Since its establishment at the beamline 16-ID-B a decade ago, laser-heated diamond anvil cell coupled with in situ synchrotron x-ray diffraction has been widely used for studying the structural properties of materials under simultaneous high pressure and high temperature conditions. Recent developments in both continuous-wave and modulated heating techniques have been focusing on resolving technical issues of the most challenging research areas. The new capabilities have demonstrated clear benefits and provide new opportunities in research areas including high-pressure melting, pressure-temperature-volume equations of state, chemical reaction, and time resolved studies.

  15. In situ formation of micron-scale Li-metal anodes with high cyclability

    SciTech Connect

    Arruda, Thomas M; Lawton, Jamie S; Kumar, Amit; Unocic, Raymond R; Kravchenko, Ivan I; Zawodzinski, Thomas A; Jesse, Stephen; Kalinin, Sergei V; Balke, Nina

    2014-01-01

    Scanning probe microscopy methods have been used to fabricate and cycle micron-scale Li anodes deposited electrochemically under nanofabricated Au current collectors. An average Li volume of 5 10^8 nm3 was deposited and cycled with 100 % coulombic efficiency for ~ 160 cycles. Integrated charge/discharge values agree with before/after topography, as well as in situ dilatometry, suggesting this is a reliable method to study solid-state electrochemical processes. In this work we illustrate the possibility to deposit highly cyclable nanometer thick Li electrodes by mature SPM and nanofab techniques which can pave the way for inexpensive nanoscale battery arrays.

  16. Highly accurate isotope measurements of surface material on planetary objects in situ

    NASA Astrophysics Data System (ADS)

    Riedo, Andreas; Neuland, Maike; Meyer, Stefan; Tulej, Marek; Wurz, Peter

    2013-04-01

    Studies of isotope variations in solar system objects are of particular interest and importance. Highly accurate isotope measurements provide insight into geochemical processes, constrain the time of formation of planetary material (crystallization ages) and can be robust tracers of pre-solar events and processes. A detailed understanding of the chronology of the early solar system and dating of planetary materials require precise and accurate measurements of isotope ratios, e.g. lead, and abundance of trace element. However, such measurements are extremely challenging and until now, they never have been attempted in space research. Our group designed a highly miniaturized and self-optimizing laser ablation time-of-flight mass spectrometer for space flight for sensitive and accurate measurements of the elemental and isotopic composition of extraterrestrial materials in situ. Current studies were performed by using UV radiation for ablation and ionization of sample material. High spatial resolution is achieved by focusing the laser beam to about Ø 20μm onto the sample surface. The instrument supports a dynamic range of at least 8 orders of magnitude and a mass resolution m/Δm of up to 800—900, measured at iron peak. We developed a measurement procedure, which will be discussed in detail, that allows for the first time to measure with the instrument the isotope distribution of elements, e.g. Ti, Pb, etc., with a measurement accuracy and precision in the per mill and sub per mill level, which is comparable to well-known and accepted measurement techniques, such as TIMS, SIMS and LA-ICP-MS. The present instrument performance offers together with the measurement procedure in situ measurements of 207Pb/206Pb ages with the accuracy for age in the range of tens of millions of years. Furthermore, and in contrast to other space instrumentation, our instrument can measure all elements present in the sample above 10 ppb concentration, which offers versatile applications

  17. High temperature measuring device

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  18. In situ measurement of the two-dimensional temperature field of a dual-jet direct-current arc plasma.

    PubMed

    Guo, Heng; Li, Peng; Li, He-Ping; Ge, Nan; Bao, Cheng-Yu

    2016-03-01

    In this paper, a real time method for an in situ measurement of the two-dimensional (2-D) temperature filed of thermal plasmas is developed with the combination of the visible image processing technique and the spectroscopic line-ratio method at two specified wavelengths. After the calibration of the gray scale values of the recorded images with the CCD cameras by the emission intensity received using a spectrometer, the 2-D temperature field of the plasma arc-jet can be obtained conveniently based on the derived gray scale values of the CCD images at two specified wavelengths and the formula similar to that of spectroscopic line-ratio method. The experimental results show that the obtained temperature fields of the plasma arc-jet at different times are qualitatively reasonable and consistent with the modeling result. This newly developed method can be employed to measure the transient temperature fields of the plasmas with fluctuations during discharges effectively. PMID:27036772

  19. In-situ temperature-controllable shear flow device for neutron scattering measurement—An example of aligned bicellar mixtures

    SciTech Connect

    Xia, Yan; Li, Ming; Kučerka, Norbert; Li, Shutao; Nieh, Mu-Ping

    2015-02-15

    We have designed and constructed a temperature-controllable shear flow cell for in-situ study on flow alignable systems. The device has been tested in the neutron diffraction and has the potential to be applied in the small angle neutron scattering configuration to characterize the nanostructures of the materials under flow. The required sample amount is as small as 1 ml. The shear rate on the sample is controlled by the flow rate produced by an external pump and can potentially vary from 0.11 to 3.8 × 10{sup 5} s{sup −1}. Both unidirectional and oscillational flows are achievable by the setting of the pump. The instrument is validated by using a lipid bicellar mixture, which yields non-alignable nanodisc-like bicelles at low T and shear-alignable membranes at high T. Using the shear cell, the bicellar membranes can be aligned at 31 °C under the flow with a shear rate of 11.11 s{sup −1}. Multiple high-order Bragg peaks are observed and the full width at half maximum of the “rocking curve” around the Bragg’s condition is found to be 3.5°–4.1°. It is noteworthy that a portion of the membranes remains aligned even after the flow stops. Detailed and comprehensive intensity correction for the rocking curve has been derived based on the finite rectangular sample geometry and the absorption of the neutrons as a function of sample angle [See supplementary material at http://dx.doi.org/10.1063/1.4908165 for the detailed derivation of the absorption correction]. The device offers a new capability to study the conformational or orientational anisotropy of the solvated macromolecules or aggregates induced by the hydrodynamic interaction in a flow field.

  20. Calcium Pyroxenes at Mercurian Surface Temperatures: Investigation of In-Situ Emissivity Spectra.

    NASA Astrophysics Data System (ADS)

    Ferrari, Sabrina; Maturilli, Alessandro; Helbert, Jörn; Rossi, Manuela; Nestola, Fabrizio; D'Amore, Mario; Hiesinger, Harald

    2014-05-01

    Several observations point to the possibility that Ca-rich (and low-Fe) clinopyroxenes could be common constituent minerals of the surface of Mercury. The upcoming ESA-JAXA BepiColombo mission to Mercury will carry on board the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) that will provide surface emissivity spectra in the wavelength range from 7-14 μm. This spectral range is very useful to identify the fine-scale structural properties of several silicates including pyroxenes. The extreme daily surface temperature range of Mercury (70 to 725 K) that significantly affects the spectral signature of minerals will make the interpretation of MERTIS observations challenging. It has been shown that spectra of clinopyroxenes with similar calcium content display a deepening of the main absorption bands, and a shift of the band minima toward higher wavelengths with increasing temperatures. Similar shifts can also be observed at constant temperature with increasing iron content in the M2 site. Therefore, the thermal expansion induced by the increasing temperature simulates the presence of a larger cation (e.g., iron vs. magnesium) within the mineral structure. Interestingly, each band shifts by a different amount, representing a marker for the real chemistry of the sample. A detailed study of the described mineral behavior is fundamental to localize those spectral bands sensitive to the daily temperature range of the Mercury surface. In combination with the temperature measurements obtained independently by the radiometer channel of MERTIS this will help to further constrain the mineralogical interpretation of the MERTIS spectral data. Here we present high-temperature (up to 750 K) laboratory emissivity spectra of several augitic pyroxenes with different calcium contents and very different magnesium to iron ratios. The spectra were derived from individual well-preserved natural crystals of several pyroxenes of less than 125 ?m in size, which approaches the

  1. In Situ Eddy Analysis in a High-Resolution Ocean Climate Model.

    PubMed

    Woodring, Jonathan; Petersen, Mark; Schmeißer, Andre; Patchett, John; Ahrens, James; Hagen, Hans

    2016-01-01

    An eddy is a feature associated with a rotating body of fluid, surrounded by a ring of shearing fluid. In the ocean, eddies are 10 to 150 km in diameter, are spawned by boundary currents and baroclinic instabilities, may live for hundreds of days, and travel for hundreds of kilometers. Eddies are important in climate studies because they transport heat, salt, and nutrients through the world's oceans and are vessels of biological productivity. The study of eddies in global ocean-climate models requires large-scale, high-resolution simulations. This poses a problem for feasible (timely) eddy analysis, as ocean simulations generate massive amounts of data, causing a bottleneck for traditional analysis workflows. To enable eddy studies, we have developed an in situ workflow for the quantitative and qualitative analysis of MPAS-Ocean, a high-resolution ocean climate model, in collaboration with the ocean model research and development process. Planned eddy analysis at high spatial and temporal resolutions will not be possible with a postprocessing workflow due to various constraints, such as storage size and I/O time, but the in situ workflow enables it and scales well to ten-thousand processing elements. PMID:26353372

  2. In situ high-resolution X-ray photoelectron spectroscopy - Fundamental insights in surface reactions

    NASA Astrophysics Data System (ADS)

    Papp, Christian; Steinrück, Hans-Peter

    2013-11-01

    Since the advent of third generation synchrotron light sources optimized for providing soft X-rays up to 2 keV, X-ray photoelectron spectroscopy (XPS) has been developed to be an outstanding tool to study surface properties and surface reactions at an unprecedented level. The high resolution allows identifying various surface species, and for small molecules even the vibrational fine structure can be resolved in the XP spectra. The high photon flux reduces the required measuring time per spectrum to the domain of a few seconds or even less, which enables to follow surface processes in situ. Moreover, it also provides access to very small coverages down to below 0.1% of a monolayer, enabling the investigation of minority species or processes at defect sites. The photon energy can be adjusted according to the requirement of a particular experiment, i.e., to maximize or minimize the surface sensitivity or the photoionization cross-section of the substrate or the adsorbate. For a few instruments worldwide, a next step forward was taken by combining in situ high-resolution spectrometers with supersonic molecular beams. These beams allow to control and vary the kinetic and internal energies of the incident molecules and provide a local pressure of up to ~10-5 mbar, which can be switched on and off in a controllable way, thus offering a well-defined time structure to study adsorption or reaction processes.

  3. High-temperature sensor

    DOEpatents

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  4. In Situ Biodiesel Production from Fast-Growing and High Oil Content Chlorella pyrenoidosa in Rice Straw Hydrolysate

    PubMed Central

    Li, Penglin; Miao, Xiaoling; Li, Rongxiu; Zhong, Jianjiang

    2011-01-01

    Rice straw hydrolysate was used as lignocellulose-based carbon source for Chlorella pyrenoidosa cultivation and the feasibility of in situ biodiesel production was investigated. 13.7 g/L sugar was obtained by enzymatic hydrolyzation of rice straw. Chlorella pyrenoidosa showed a rapid growth in the rice straw hydrolysate medium, the maximum biomass concentration of 2.83 g/L was obtained in only 48 hours. The lipid content of the cells reached as high as 56.3%. In situ transesterification was performed for biodiesel production. The optimized condition was 1 g algal powder, 6 mL n-hexane, and 4 mL methanol with 0.5 M sulfuric acid at the temperature of 90°C in 2-hour reaction time, under which over 99% methyl ester content and about 95% biodiesel yield were obtained. The results suggested that the method has great potential in the production of biofuels with lignocellulose as an alternative carbon source for microalgae cultivation. PMID:21318171

  5. In Situ, High-Resolution Profiles of Labile Metals in Sediments of Lake Taihu.

    PubMed

    Wang, Dan; Gong, Mengdan; Li, Yangyang; Xu, Lv; Wang, Yan; Jing, Rui; Ding, Shiming; Zhang, Chaosheng

    2016-01-01

    Characterizing labile metal distribution and biogeochemical behavior in sediments is crucial for understanding their contamination characteristics in lakes, for which in situ, high-resolution data is scare. The diffusive gradient in thin films (DGT) technique was used in-situ at five sites across Lake Taihu in the Yangtze River delta in China to characterize the distribution and mobility of eight labile metals (Fe, Mn, Zn, Ni, Cu, Pb, Co and Cd) in sediments at a 3 mm spatial resolution. The results showed a great spatial heterogeneity in the distributions of redox-sensitive labile Fe, Mn and Co in sediments, while other metals had much less marked structure, except for downward decreases of labile Pb, Ni, Zn and Cu in the surface sediment layers. Similar distributions were found between labile Mn and Co and among labile Ni, Cu and Zn, reflecting a close link between their geochemical behaviors. The relative mobility, defined as the ratio of metals accumulated by DGT to the total contents in a volume of sediments with a thickness of 10 mm close to the surface of DGT probe, was the greatest for Mn and Cd, followed by Zn, Ni, Cu and Co, while Pb and Fe had the lowest mobility; this order generally agreed with that defined by the modified BCR approach. Further analyses showed that the downward increases of pH values in surface sediment layer may decrease the lability of Pb, Ni, Zn and Cu as detected by DGT, while the remobilization of redox-insensitive metals in deep sediment layer may relate to Mn cycling through sulphide coprecipitation, reflected by several corresponding minima between these metals and Mn. These in situ data provided the possibility for a deep insight into the mechanisms involved in the remobilization of metals in freshwater sediments. PMID:27608033

  6. In situ crystallization of ionic liquid [Emim][PF6] from methanol solution under high pressure.

    PubMed

    Li, Haining; Su, Lei; Zhu, Xiang; Cheng, Xuerui; Yang, Kun; Yang, Guoqiang

    2014-07-24

    The solubility of 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) in methanol under high pressure is newly measured quantitatively according to the correlation between the ratios of Raman intensity and the concentrations. In situ crystallization and cation conformation of [Emim][PF6] from methanol solution under high pressure have been investigated by using Raman spectroscopy in detail. Remarkably, crystal polymorphism was observed and two crystalline phases (phases I and II) coexisted under high pressure up to ∼ 1.4 GPa. However, only phase II was obtained by recrystallization at ∼ 2 GPa. Our findings may facilitate the development of an effective way for crystallization and purification of ionic liquids under high pressure. PMID:24968114

  7. Rapid, high-resolution in situ hybridization histochemistry with radioiodinated synthetic oligonucleotides

    SciTech Connect

    Lewis, M.E.; Arentzen, R.; Baldino, F. Jr.

    1986-01-01

    In situ hybridization histochemistry is a valuable technique for localizing specific messenger RNA (mRNA) and detecting changes in gene expression. Generally, the mRNA of interest has been detected by probes obtained from cloned DNA and labelled to high specific activity by nick translation. Such probes have a number of disadvantages which can be circumvented by the use of short synthetic oligonucleotides designed to be complementary to a known mRNA sequence. We report here that synthetic oligonucleotides complementary to part of the mRNA coding for rat arginine-vasopressin (AVP) can be labelled to high specific activity with (/sup 125/I), using either the primer extension method with the Klenow fragment of DNA polymerase I or the 3'-tailing method with terminal deoxynucleotidyl transferase. Both AVP probes hybridized well to the magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei. A strong autoradiographic signal was present by 2 days, with grains largely confined to the perikaryon. These results compare favorably to those obtained with (/sup 32/P)- or (/sup 3/H)-labelled probes. Given the ease of the 3'-tailing method, (/sup 125/I)-labelled oligonucleotides appear to be especially useful probes for in situ hybridization histochemistry.

  8. In situ flash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

    NASA Astrophysics Data System (ADS)

    Moser, Stefan; Nau, Siegfried; Salk, Manfred; Thoma, Klaus

    2014-02-01

    The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s-1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s-1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

  9. Sustained ocular drug delivery from a temperature and pH triggered novel in situ gel system.

    PubMed

    Gupta, Himanshu; Jain, Sanyog; Mathur, Rashi; Mishra, Pushpa; Mishra, Anil K; Velpandian, T

    2007-11-01

    Various ocular diseases like glaucoma, conjunctivitis, and dry eye syndrome require frequent drug administration. Poor ocular bioavailability of drugs (< 1%) from conventional eye drops is due mainly to the precorneal loss factors that include rapid tear turnover, nonproductive absorption, transient residence time in the cul-de-sac, and the relative impermeability of the drugs to corneal epithelial membrane. These problems may be overcome by the use of in situ gel-forming systems that are instilled as drops into the eye and undergo a sol-gel transition in the cul-de-sac. Our present work describes the formulation and evaluation of an ocular delivery system of timolol maleate based on the concept of both temperature and pH-triggered in situ gelation. Pluronic F-127 (a thermosensitive polymer) in combination with chitosan (pH-sensitive polymer also acts as permeation enhancer) was used as gelling agent. The developed formulation was characterized for various in vitro parameters e.g., clarity, gelation temperature and pH, isotonicity, sterility, rheological behavior, drug release profile, transcorneal permeation profile, and ocular irritation. Developed formulation was clear, isotonic solution, that converted into gel at temperatures above 35 degrees C and pH 6.9-7.0. A significant higher drug transport across corneal membrane and increased ocular retention time was observed using the developed formulation. The developed system is a viable alternative to conventional eye drops for the treatment of glaucoma and various other ocular diseases. PMID:18027180

  10. Towards Determining the Upper Temperature Limits to Life on Earth: An In-situ Sulfide-Microbial Incubator

    NASA Astrophysics Data System (ADS)

    Kelley, D.; Baross, J.; Delaney, J.; Girguis, P.; Schrenk, M.

    2004-12-01

    Determining the maximum conditions under which life thrives, survives, and expires is critical to understanding how and where life might have evolved on our planet and for investigation of life in extraterrestrial environments. Submarine black smoker systems are optimal sites to study such questions because thermal gradients are extreme and accessible within the chimney walls under high-pressure conditions. Intact cells containing DNA and ribosomes have been observed even within the most extreme environments of sulfide structure walls bounded by 300\\deg C fluids. Membrane lipids from archaea have been detected in sulfide flanges and chimneys where temperatures are believed to be 200-300\\deg C. However, a balanced inquiry into the limits of life must focus on characterization of the actual conditions in a given system that favor reactions necessary to initiate and/or sustain life. At present, in-situ instrumentation of sulfide deposits is the only effective way to gain direct access to these natural high-temperature environments for documentation and experimentation. With this goal in mind, three prototype microbial incubators were developed with funding from the NSF, University of Washington, and the W.M. Keck Foundation. The incubators were deployed in 2003 in the walls of active black smoker chimneys in the Mothra Hydrothermal Field, Endeavour Segment of the Juan de Fuca Ridge. All instruments were successfully recovered in 2004, and one was redeployed for a short time-series experiment. Each 53-cm-long titanium assembly houses 27 temperature sensors that record temperatures from 0 to 500\\deg C within three discrete incubation chambers. Data are logged in a separate housing and inductively coupled links provide access to the data loggers without removal of the instruments. During the initial deployment, data were collected from 189 to 245 days, with up to ˜478° K temperature measurements completed for an individual instrument. Temperatures within the chimney

  11. In situ FT-IR study on the homogeneous nucleation of nanoparticles of titanium oxides from highly supersaturated vapor

    NASA Astrophysics Data System (ADS)

    Ishizuka, Shinnosuke; Kimura, Yuki; Yamazaki, Tomoya

    2016-09-01

    The formation of nanoparticles of titanium oxides by homogeneous nucleation from highly supersaturated vapors was investigated by in situ Fourier transform IR spectroscopy and by observation of the resulting nanoparticles by transmission electron microscopy (TEM). Titanium metal was thermally evaporated in a specially designed chamber under a gaseous atmosphere of oxygen and argon. Nanoparticles nucleated and subsequently grew as they flew freely through the oxidizing gas atmosphere. Nascent nanoparticles of titanium oxides showed a broad IR absorption band at 10-20 μm. Subsequently, the cooled nanoparticles showed a sharp crystalline anatase feature at 12.8 μm. TEM observations showed the formation of spherical anatase nanoparticles. The IR spectral evolution showed that the titanium oxides nucleated as metastable liquid droplets, and that crystallization proceeded through secondary nucleation from the supercooled liquid droplets. This suggests that history of the titanium oxide nanoparticles, such as the temperature and oxidation that they experience after nucleation, determines their polymorphic form.

  12. Impact of high-frequency ultrasound on nanocomposite microcapsules: in silico and in situ visualization.

    PubMed

    Korolovych, V F; Grishina, O A; Inozemtseva, O A; Selifonov, A V; Bratashov, D N; Suchkov, S G; Bulavin, L A; Glukhova, O E; Sukhorukov, G B; Gorin, D A

    2016-01-28

    The impact of high-frequency (1.2 MHz) ultrasound with a power density of 0.33 W cm(-2) on microcapsule nanocomposite shells with embedded zinc oxide nanoparticles was investigated by exploring modeling simulations and direct visualization. For the first time the sonication effect has been monitored in situ on individual microcapsules upon exposure of their aqueous suspension to ultrasound. The stress distribution on the microcapsule shell for the impact of ultrasound with high (1.2 MHz) and low (20 kHz) frequency at two fixed intensities (0.33 and 30 W cm(-2)) has been modeled. As shown in silico and experimentally the nanocomposite microcapsules were destroyed more effectively by the action of high-frequency (1.2 MHz) ultrasound in comparison to the low frequency (20 kHz) one with the same power density. PMID:26646077

  13. Versatile variable temperature insert at the DEIMOS beamline for in situ electrical transport measurements.

    PubMed

    Joly, L; Muller, B; Sternitzky, E; Faullumel, J G; Boulard, A; Otero, E; Choueikani, F; Kappler, J P; Studniarek, M; Bowen, M; Ohresser, P

    2016-05-01

    The design and the first experiments are described of a versatile cryogenic insert used for its electrical transport capabilities. The insert is designed for the cryomagnet installed on the DEIMOS beamline at the SOLEIL synchrotron dedicated to magnetic characterizations through X-ray absorption spectroscopy (XAS) measurements. This development was spurred by the multifunctional properties of novel materials such as multiferroics, in which, for example, the magnetic and electrical orders are intertwined and may be probed using XAS. The insert thus enables XAS to in situ probe this interplay. The implementation of redundant wiring and careful shielding also enables studies on operating electronic devices. Measurements on magnetic tunnel junctions illustrate the potential of the equipment toward XAS studies of in operando electronic devices. PMID:27140143

  14. In-situ post-deposition thermal annealing of co-evaporated Cu(InGa)Se2 thin films deposited at low temperatures

    SciTech Connect

    Wilson, James D.; McCandless, Brian E.; Birkmire, Robert W.; Shafarman, William N.

    2009-06-09

    The effects of deposition temperature and in-situ post-deposition annealing on the microstructure of coevaporated Cu(InGa)Se2 thin films and on the performance of the resulting solar cell devices have been characterized. Films were deposited at substrate temperatures of 150°C, 300°C and 400°C. Films were also deposited at these temperatures and then annealed in-situ at 550°C for 10 minutes. In as -deposited films without annealing, additional XRD reflections that may be due to a polytypic modification of the chalcopyrite phase were observed. Films deposited at 150°C were Se-rich. Post-deposition annealing caused microstructural changes in all films and improved the resulting solar cells. Only films deposited at 400°C, however, yielded high-efficiency devices after post-deposition annealing that were equivalent to devices made from films grown at 550°C. Films originally deposited at 300°C yielded devices after post-deposition annealing with VOC close to that of devices made from films grown at 550°C, despite smaller grain size.

  15. Doxorubicin-induced co-assembling nanomedicines with temperature-sensitive acidic polymer and their in-situ-forming hydrogels for intratumoral administration.

    PubMed

    Wan, Jiangshan; Geng, Shinan; Zhao, Hao; Peng, Xiaole; Zhou, Qing; Li, Han; He, Ming; Zhao, Yanbing; Yang, Xiangliang; Xu, Huibi

    2016-08-10

    Doxorubicin (DOX)-induced co-assembling nanomedicines (D-PNAx) with temperature-sensitive PNAx triblock polymers have been developed for regional chemotherapy against liver cancer via intratumoral administration in the present work. Owing to the formation of insoluble DOX carboxylate, D-PNAx nanomedicines showed high drug-loading and entrapment efficacy via a simple mixing of doxorubicin hydrochloride and PNAx polymers. The sustained releasing profile of D-PNA100 nanomedicines indicated that only 9.4% of DOX was released within 1day, and 60% was released during 10days. Based on DOX-induced co-assembling behavior and their temperature sensitive in-situ-forming hydrogels, D-PNA100 nanomedicines showed excellent antitumor activity against H22 tumor using intratumoral administration. In contrast to that by free DOX solution (1.13±0.04 times at 9days) and blank PNA100 (2.11±0.34 times), the tumor volume treated by D-PNA100 had been falling to only 0.77±0.13 times of original tumor volume throughout the experimental period. In vivo biodistribution of DOX indicated that D-PNA100 nanomedicines exhibited much stronger DOX retention in tumor tissues than free DOX solution via intratumoral injection. D-PNA100 nanomedicines were hopeful to be developed as new temperature sensitive in-situ-forming hydrogels via i.t. injection for regional chemotherapy. PMID:27282415

  16. Dengue virus surveillance in Singapore reveals high viral diversity through multiple introductions and in situ evolution.

    PubMed

    Lee, Kim-Sung; Lo, Sharon; Tan, Sharon Siok-Yin; Chua, Rachel; Tan, Li-Kiang; Xu, Helen; Ng, Lee-Ching

    2012-01-01

    Dengue fever, a vector-borne disease, has caused tremendous burden to countries in the tropics and sub tropics. Over the past 20 years, dengue epidemics have become more widespread, severe and frequent. This study aims to understand the dynamics of dengue viruses in cosmopolitan Singapore. Envelope protein gene sequences of all four dengue serotypes (DENV-1-DENV-4) obtained from human sera in Singapore (2008-2010) revealed that constant viral introductions and in situ evolution contribute to viral diversity in Singapore and play important roles in shaping the epidemiology of dengue in the island state. The diversity of dengue viruses reported here could be a reflection of the on-going dengue situation in the region given Singapore's location in a dengue hyperendemic region and its role as the regional hub for travels and trade. Though cosmopolitan genotype of DENV-2 has remained as the predominant strain circulating in Singapore, we uncovered evidence of in situ evolution which could possibly result in viruses with improved fitness. While we have previously shown that a switch in the predominant dengue serotype could serve as a warning for an impending outbreak, our current data shows that a replacement of a predominant viral clade, even in the absence of a switch in predominant serotype, could signal a possible increase in dengue transmission. The circulating dengue viruses in Singapore are highly diverse, a situation which could offer ample opportunities for selection of strains of higher fitness, thus increasing the risk of outbreaks despite a low Aedes population. PMID:22036707

  17. Scaling an in situ network for high resolution modeling during SMAPVEX15

    NASA Astrophysics Data System (ADS)

    Coopersmith, E. J.; Cosh, M. H.; Jacobs, J. M.; Jackson, T. J.; Crow, W. T.; Holifield Collins, C.; Goodrich, D. C.; Colliander, A.

    2015-12-01

    Among the greatest challenges within the field of soil moisture estimation is that of scaling sparse point measurements within a network to produce higher resolution map products. Large-scale field experiments present an ideal opportunity to develop methodologies for this scaling, by coupling in situ networks, temporary networks, and aerial mapping of soil moisture. During the Soil Moisture Active Passive Validation Experiments in 2015 (SMAPVEX15) in and around the USDA-ARS Walnut Gulch Experimental Watershed and LTAR site in southeastern Arizona, USA, a high density network of soil moisture stations was deployed across a sparse, permanent in situ network in coordination with intensive soil moisture sampling and an aircraft campaign. This watershed is also densely instrumented with precipitation gages (one gauge/0.57 km2) to monitor the North American Monsoon System, which dominates the hydrologic cycle during the summer months in this region. Using the precipitation and soil moisture time series values provided, a physically-based model is calibrated that will provide estimates at the 3km, 9km, and 36km scales. The results from this model will be compared with the point-scale gravimetric samples, aircraft-based sensor, and the satellite-based products retrieved from NASA's Soil Moisture Active Passive mission.

  18. High-resolution telomere fluorescence in situ hybridization reveals intriguing anomalies in germ cell tumors.

    PubMed

    Shekhani, Mohammed Talha; Barber, John R; Bezerra, Stephania M; Heaphy, Christopher M; Gonzalez Roibon, Nilda Diana; Taheri, Diana; Reis, Leonardo O; Guner, Gunes; Joshu, Corinne E; Netto, George J; Meeker, Alan K

    2016-08-01

    Testicular germ cell tumor (TGCT) is the most common malignancy of young men. Most patients are completely cured, which distinguishes these from most other malignancies. Orchiectomy specimens (n=76) were evaluated using high-resolution (single-cell discriminative) telomere-specific fluorescence in situ hybridization (FISH) with simultaneous Oct4 immunofluorescence to describe telomere length phenotype in TGCT neoplastic cells. For the first time, the TGCT precursor lesion, germ cell neoplasia in situ (GCNIS) is also evaluated in depth. The intensity of the signals from cancerous cells was compared to the same patient's reference cells-namely, healthy germ cells (defined as "medium" length) and interstitial/somatic cells (defined as "short" telomere length). We observed short telomeres in most GCNIS and pure seminomas (P=.006 and P=.0005, respectively). In contrast, nonseminomas displayed longer telomeres. Lesion-specific telomere lengths were documented in mixed tumor cases. Embryonal carcinoma (EC) demonstrated the longest telomeres. A fraction of EC displays the telomerase-independent alternative lengthening of telomeres (ALT) phenotype (24% of cases). Loss of ATRX or DAXX nuclear expression was strongly associated with ALT; however, nuclear expression of both proteins was retained in half of ALT-positive ECs. The particular distribution of telomere lengths among TGCT and GCNIS precursors implicate telomeres anomalies in pathogenesis. These results may advise management decisions as well. PMID:27085557

  19. In Situ Density Measurement of Basaltic Melts at High Pressure by X-ray Absorption Method

    NASA Astrophysics Data System (ADS)

    Ando, R.; Ohtani, E.; Suzuki, A.; Urakawa, S.; Katayama, Y.

    2004-12-01

    Density of silicate melt at high pressure is one of the most important properties to understand magma migration in the planetary interior. However, because of experimental difficulties, the density of magma at high pressure is poorly known. Katayama et al. (1996) recently developed a new in situ density measurement method for metallic melts, based on the density dependency of X-ray absorption in the sample. In this study, we tried to measure the density of basaltic melt by this absorption method. When X-ray is transmitted to the sample, the intensity of the transmitted X-ray beam (I) is expressed as follows; I=I0exp(-μ ρ t), where I0 is the intensity of incident X-ray beam, μ is the mass absorption coefficient, ρ is the density of the sample, and t is the thickness of the sample. If t and μ are known, we can determine the density of the sample by measuring I and I0. This is the principle of the absorption method for density measurement. In this study, in order to determine t, we used a single crystalline diamond cylinder as a sample capsule, diamond is less compressive and less deformable so that even at high pressure t (thickness of the sample at the point x) is expressed as follows; t = 2*(R02-x2)1/2, R0 is the inner radius of cylinder at the ambient condition, and x is distance from a center of the capsule. And diamond also shows less absorption so that this make it possible to measure the density of silicate melt with smaller absorption coefficient than metallic melts. In order to know the μ of the sample, we measured both densities (ρ ) and absorptions (I/I0) for some glasses and crystals with same composition of the sample at the ambient condition, and calculated as fallows; μ =ln(I/I0)/ρ . Experiments were made at the beamline (BL22XU) of SPring-8. For generation of high pressure and high temperature, we used DIA-type cubic anvil apparatus (SMAP180) there. We used tungsten carbide anvils with the edge-length of 6 mm. The energy of monochromatic X

  20. The effect of in-situ high-temperature high-pressure on the structural changes of single-crystal relaxor ferroelectrics PbSc1/2Ta1/2O3 (PST) and PbSc1/2Nb1/2O3 (PSN)

    NASA Astrophysics Data System (ADS)

    Waeselmann, Naemi; Mihailova, Boriana; Gospodinov, Marin; Bismayer, Ullrich

    2013-06-01

    Relaxor ferroelectrics (relaxor) of the perovskite structure (ABO3) have remarkably high dielectric permittivity dependent on temperature and frequency as well as remarkable piezoelectric and electro-optic coefficients. These structurally heterogeneous materials undergo a sequence of structural changes on the mesoscopic scale associated with characteristic temperatures resulting from the development of polar order on temperature decrease. Pressure increase on the other hand favors antiferrodistortive order at room temperature. To explore the importance of the antiferrodistortive coupling on the development of polar order simultaneous high-temperature high-pressure Raman studies were undertaken on single crystals of PST and PSN from 400-600 K over pressures extending to 9 GPa. We find that the first pressure-induced transition pc1 decreases with temperature while the second transition pc2 is relatively temperature independent. The behavior of pc1 is interpreted as a weakening of the polar coupling, which in turn facilitates the evolution of the preexisting medium-range antiferodistortive order into a long-range order. The near constant value of pc2 suggests that it is independent of the state of polar coupling and is mainly related to the initial correlation length of antiferrodistortive order. Thus the coexistence of both polar order and antiferrodistortive order is required for the occurrence of the relaxor state. Now at: University of Washington.

  1. Improving the accuracy of MODIS 8-day snow products with in situ temperature and precipitation data

    NASA Astrophysics Data System (ADS)

    Dong, Chunyu; Menzel, Lucas

    2016-03-01

    MODIS snow data are appropriate for a wide range of eco-hydrological studies and applications in the fields of snow-related hazards, early warning systems and water resources management. However, the high spatio-temporal resolution of the remotely sensed data is often biased by snow misclassifications, and cloud cover frequently limits the availability of the MODIS-based snow cover information. In this study, we applied a four-step methodology that aims to optimize the accuracy of MODIS snow data. To reduce the cloud fraction, 8-day MODIS data from both the Aqua and Terra satellites were combined. Neighborhood analysis was applied as well for this purpose, and it also contributed to the retrieval of some omitted snow. Two meteorological filters were then applied to combine information from station-based measurements of minimum ground temperature, precipitation and air temperature. This procedure helped to reduce the overestimation of snow cover. To test this technique, the methodology was applied to the Rhineland-Palatinate region in southwestern Germany (approximately 20,000 km2), where cloud cover is especially high during winter and surface heterogeneity is complex. The results show that mean annual cloud coverage (reference period 2002-2013) of the 8-day MODIS snow maps could be reduced using this methodology from approximately 14% to 4.5%. During the snow season, obstruction by clouds could be reduced by even a higher degree, but still remains at about 11%. Further, the overall snow overestimation declined from 11.0-11.9% (using the original Aqua-Terra data) to 1.0-1.5%. The method is able to improve the overall accuracy of the 8-day MODIS snow product from originally 78% to 89% and even to 93% during cloud free periods.

  2. In-situ and non-destructive focus determination device for high-precision laser applications

    NASA Astrophysics Data System (ADS)

    Armbruster, Oskar; Naghilou, Aida; Pöhl, Hannes; Kautek, Wolfgang

    2016-09-01

    A non-destructive, in-line, and low-cost focusing device based on an image sensor has been developed and demonstrated. It allows an in situ focus determination for a broad variety of laser types (e.g. cw and pulsed lasers). It provides stringent focusing conditions with high numerical apertures. This approach does not require sub-picosecond and/or auxiliary lasers, or high fluences above damage thresholds. Applications of this system include, but are not limited to the laser-illumination of micro-electrodes, pump-probe microscopy on thin films, and laser ablation of small samples without sufficient surface area for focus determination by ablation. An uncertainty of the focus position by an order of magnitude less than the respective Rayleigh length could be demonstrated.

  3. Microbial diversity in long-term water-flooded oil reservoirs with different in situ temperatures in China

    PubMed Central

    Zhang, Fan; She, Yue-Hui; Chai, Lu-Jun; Banat, Ibrahim M.; Zhang, Xiao-Tao; Shu, Fu-Chang; Wang, Zheng-Liang; Yu, Long-Jiang; Hou, Du-Jie

    2012-01-01

    Water-flooded oil reservoirs have specific ecological environments due to continual water injection and oil production and water recycling. Using 16S rRNA gene clone library analysis, the microbial communities present in injected waters and produced waters from four typical water-flooded oil reservoirs with different in situ temperatures of 25°C, 40°C, 55°C and 70°C were examined. The results obtained showed that the higher the in situ temperatures of the oil reservoirs is, the less the effects of microorganisms in the injected waters on microbial community compositions in the produced waters is. In addition, microbes inhabiting in the produced waters of the four water-flooded oil reservoirs were varied but all dominated by Proteobacteria. Moreover, most of the detected microbes were not identified as indigenous. The objective of this study was to expand the pictures of the microbial ecosystem of water-flooded oil reservoirs. PMID:23094135

  4. In situ transmission electron microscopy observation of dislocation motion in 9Cr steel at elevated temperatures: influence of shear stress on dislocation behavior.

    PubMed

    Yamada, Susumu; Sakai, Takayuki

    2014-12-01

    To elucidate high-temperature plastic deformation (creep) mechanism in materials, it is essential to observe dislocation motion under tensile loading. There are many reports on in situ transmission electron microscopy (TEM) observations in the literature; however, the relationship between the dislocation motion and shear stress in 9Cr steel is still not clear. In this study, in order to evaluate this relationship quantitatively, in situ TEM observations were carried out in conjunction with finite element method (FEM) analysis. A tensile test sample was strained at an elevated temperature (903 K) inside a transmission electron microscope, and the stress distribution in the strained sample was analyzed by FEM. The dislocation behavior was clearly found to depend on the shear stress. At a shear stress of 66 MPa, both the dislocation velocity and mobile dislocation density were low. However, a high shear stress level of 95 MPa caused a noticeable increase in the dislocation velocity and mobile dislocation density. Furthermore, in this article, we discuss the dependence of the dislocation behavior on stress. The results presented here also indicate that the relationship between the microstructure and the strength of materials can be revealed by the methods used in this work. PMID:25298228

  5. High-Temperature Superconductivity

    SciTech Connect

    Peter Johnson

    2008-11-05

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  6. High-Temperature Superconductivity

    ScienceCinema

    Peter Johnson

    2010-01-08

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors ? materials that carry electrical c

  7. High Temperature Capacitor Development

    SciTech Connect

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  8. High temperature pressure gauge

    DOEpatents

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  9. High-temperature electronics

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-01-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  10. High-temperature electronics

    NASA Astrophysics Data System (ADS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-02-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  11. Sensor Fabrication Method for in Situ Temperature and Humidity Monitoring of Light Emitting Diodes

    PubMed Central

    Lee, Chi-Yuan; Su, Ay; Liu, Yin-Chieh; Chan, Pin-Cheng; Lin, Chia-Hung

    2010-01-01

    In this work micro temperature and humidity sensors are fabricated to measure the junction temperature and humidity of light emitting diodes (LED). The junction temperature is frequently measured using thermal resistance measurement technology. The weakness of this method is that the timing of data capture is not regulated by any standard. This investigation develops a device that can stably and continually measure temperature and humidity. The device is light-weight and can monitor junction temperature and humidity in real time. Using micro-electro-mechanical systems (MEMS), this study minimizes the size of the micro temperature and humidity sensors, which are constructed on a stainless steel foil substrate (40 μm-thick SS-304). The micro temperature and humidity sensors can be fixed between the LED chip and frame. The sensitivities of the micro temperature and humidity sensors are 0.06 ± 0.005 (Ω/°C) and 0.033 pF/%RH, respectively. PMID:22319303

  12. The 'Nuts and Bolts' of 13C NMR Spectroscopy at Elevated-Pressures and -Temperatures for Monitoring In Situ CO2 Conversion to Metal Carbonates

    NASA Astrophysics Data System (ADS)

    Moore, J. K.; Surface, J. A.; Skemer, P. A.; Conradi, M. S.; Hayes, S. E.

    2013-12-01

    characterization of multiple metastable mineral phases in pure forms and in mixtures. Notably, NMR spectroscopy is able to observe signals from amorphous materials, and mixtures of both crystalline and amorphous species can be analyzed. NMR results are verified through a combination of Raman spectroscopy and powder XRD (of crystalline species). Further, we have examined the effects on mineralization reactions of pH gradients in the sample--also monitored in situ by NMR--and these results will be presented. Reference: 'In Situ Measurement of Magnesium Carbonate Formation from CO2 Using Static High-Pressure and -Temperature 13C NMR' J. Andrew Surface, Philip Skemer, Sophia E. Hayes, and Mark S. Conradi, Environ. Sci. Technol. 2013, 47, 119-125. DOI: 10.1021/es301287n

  13. High temperature electronics

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1991-03-01

    In recent years, the aerospace propulsion and space power communities have acknowledged a growing need for electronic devices that are capable of sustained high-temperature operation. Aeropropulsion applications for high-temperature electronic devices include engine ground test instrumentation such as multiplexers, analog-to-digital converters, and telemetry systems capable of withstanding hot section engine temperatures in excess of 600 C. Uncooled operation of control and condition monitoring systems in advanced supersonic aircraft would subject the electronics to temperatures in excess of 300 C. Similarly, engine-mounted integrated electronic sensors could reach temperatures which exceed 500 C. In addition to aeronautics, there are many other areas that could benefit from the existence of high-temperature electronic devices. Space applications include power electronic devices for space platforms and satellites. Since power electronics require radiators to shed waste heat, electronic devices that operate at higher temperatures would allow a reduction in radiator size. Terrestrial applications include deep-well drilling instrumentation, high power electronics, and nuclear reactor instrumentation and control. To meet the needs of the applications mentioned previously, the high-temperature electronics (HTE) program at the Lewis Research Center is developing silicon carbide (SiC) as a high-temperature semiconductor material. Research is focused on developing the crystal growth, growth modeling, characterization, and device fabrication technologies necessary to produce a family of SiC devices. Interest in SiC has grown dramatically in recent years due to solid advances in the technology. Much research remains to be performed, but SiC appears ready to emerge as a useful semiconductor material.

  14. High temperature structural silicides

    SciTech Connect

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  15. High temperature probe

    DOEpatents

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  16. High Temperature ESP Monitoring

    SciTech Connect

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  17. Structural characterizaiton and gas reactions of small metal particles by high-resolution, in-situ TEM and TED

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The existing in-situ transmission electron microscopy (TEM) facility was improved by adding a separately pumped mini-specimen chamber. The chamber contains wire-evaporation sources for three metals and a specimen heater for moderate substrate temperatures. A sample introduction device was constructed, installed, and tested, facilitating rapid introduction of a specimen into the mini-chamber while maintaining the background pressure in that chamber in the 10(-9) millibar range. Small particles and clusters of Pd, grown by deposition from the vapor phase in an in-situ TEM facility on amorphous and crystalline support films of alumina and on ultra-thin carbon films, were analyzed by conventional high-resolution TEM and image analysis in terms of detectability, number density, and size distribution. The smallest particles that could be detected and counted contained no more than 6 atoms; size determinations could be made for particles 1 nm in diameter. The influence of various oxygen plasma treatments, annealing treatments, and of increasing the substrate temperature during deposition was investigated. The TEM technique was employed to demonstrate that under otherwise identica l conditions the lattice parameter of Pd particles in the 1 to 2 nm size range and supported in random orientation on ex-situ prepared mica films is expanded by some 3% when compared to 5 nm size particles. It is believed that this expansion is neither a small-particle diffraction effect nor due to pseudomorphism, but that it is due to a annealing-induced transformation of the small as-deposited particles with predominantly composite crystal structures into larger particles with true f.c.c. structure and thus inherently smaller lattice parameter.

  18. Evaluation of “all weather” microwave-derived land surface temperatures with in situ CEOP measurements

    NASA Astrophysics Data System (ADS)

    Catherinot, J.; Prigent, C.; Maurer, R.; Papa, F.; JiméNez, C.; Aires, F.; Rossow, W. B.

    2011-12-01

    Land surface skin temperature Ts plays a key role in meteorological and climatological processes but the availability and the accuracy of Ts measurements over land are still limited, especially under cloudy conditions. Ts estimates from infrared satellite observations can only be derived under clear sky. Passive microwave measurements are much less affected by clouds and can provide Ts regardless of the cloud conditions. A neural network inversion including first guess information has been previously developed to retrieve Ts, along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from Special Sensor Microwave/Imager measurements, with a spatial resolution of 0.25° × 0.25°, at least twice daily. In this study, Ts estimates are evaluated through careful comparisons with in situ measurements in different environments over a full annual cycle. Under clear sky conditions, the quality of our microwave neural network retrieval is equivalent to the infrared International Satellite Cloud Climatology Project products, for most in situ stations, with errors ˜3 K as compared to in situ measurements. The performance of the microwave algorithm is similar under clear and cloudy conditions, confirming the potential of the microwaves under clouds. The Ts accuracy does not depend upon the surface emissivity, as the variability of this parameter is accounted for in the processing. Our microwave Ts have been calculated for more than 15 years (1993 to mid-2008). These "all weather" Ts are a very valuable complement to the IR-derived Ts, for use in atmospheric and surface models.

  19. Assessing microbial processes in deep-sea hydrothermal systems by incubation at in situ temperature and pressure

    NASA Astrophysics Data System (ADS)

    McNichol, Jesse; Sylva, Sean P.; Thomas, François; Taylor, Craig D.; Sievert, Stefan M.; Seewald, Jeffrey S.

    2016-09-01

    At deep-sea hydrothermal vents, a large source of potential chemical energy is created when reducing vent fluid and oxidizing seawater mix. In this environment, chemolithoautotrophic microbes catalyze exergonic redox reactions which in turn provide the energy needed to fuel their growth and the fixation of CO2 into biomass. In addition to producing new organic matter, this process also consumes compounds contained both in vent fluid and entrained seawater (e.g. H2, NO3-). Despite their biogeochemical importance, such reactions have remained difficult to quantify due to methodological limitations. To address this knowledge gap, this study reports a novel application of isobaric gas-tight fluid samplers for conducting incubations of hydrothermal vent fluids at in situ temperature and pressure. Eighteen ~24 h incubations were carried out, representing seven distinct conditions that examine amendments consisting of different electron donors and acceptors. Microbial activity was observed in all treatments, and time series chemical measurements showed that activity was limited by electron acceptor supply, confirming predictions based on geochemical data. Also consistent with these predictions, the presence of nitrate increased rates of hydrogen consumption and yielded ammonium as a product of nitrate respiration. The stoichiometry of predicted redox reactions was also determined, revealing that the sulfur and nitrogen cycles are incompletely understood at deep-sea vents, and likely involve unknown intermediate redox species. Finally, the measured rates of redox processes were either equal to or far greater than what has been reported in previous studies where in situ conditions were not maintained. In addition to providing insights into deep-sea hydrothermal vent biogeochemistry, the methods described herein also offer a practical approach for the incubation of any deep-sea pelagic sample under in situ conditions.

  20. High temperature electronics technology

    NASA Astrophysics Data System (ADS)

    Dening, J. C.; Hurtle, D. E.

    1984-03-01

    This report summarizes the barrier metallization developments accomplished in a program intended to develop 300 C electronic controls capability for potential on-engine aircraft engine application. In addition, this report documents preliminary life test results at 300 C and above and discusses improved design practices required for high temperature integrated injection logic semiconductors. Previous Phase 1 activities focused on determining the viability of operating silicon semiconductor devices over the -55 C to +300 C temperature range. This feasibility was substantiated but the need for additional design work and process development was indicated. Phase 2 emphasized the development of a high temperature metallization system as the primary development need for high temperature silicon semiconductor applications.

  1. Trends in Mars Thermospheric Density and Temperature Structure Obtained from MAVEN In-situ Datasets: Interpretation Using Global Models

    NASA Astrophysics Data System (ADS)

    Bougher, Stephen W.; Tolson, Robert H.; Mahaffy, Paul R.; Johnston, Timothy E.; Olsen, Kirk; Bell, Jared M.

    2015-04-01

    The Mars thermosphere-ionosphere-exosphere (TIE) system constitutes the atmospheric reservoir (i.e. available cold and hot planetary neutral and thermal ion species) that regulates present day escape processes from the planet. Without knowledge of the physics and chemistry creating this TIE region and driving its variations (e.g., solar cycle, seasonal), it is not possible to constrain either the short-term or long-term histories of atmosphere escape. The characterization of this upper atmosphere reservoir is one of the major science objectives of the MAVEN mission.We investigate both in-situ Neutral Gas and Ion Mass Spectrometer (NGIMS) neutral densities/temperatures and Accelerometer Experiment (ACC) reaction wheel (RW) derived mass densities/temperatures obtained over the first ~400 orbits. This sampling occurs when periapsis latitudes ranged from about 32° to 74°N periapsis local mean solar times (LMST) ranged from about 15:00 to 06:00; and corresponding periapsis altitudes ranged from ~200 km down to ~150 km. This dayside in-situ sampling lasted until about 17-December-2014, after which the periapsis began moving Southward toward nightside Northern mid-latitudes. During this dayside period, monthly mean solar EUV-UV fluxes corresponded to F10.7 ~ 150-160 at Earth (solar moderate conditions) and the Martian season was approaching perihelion (Ls ~ 205 to 254°).Thermospheric trends (e.g. latitude, local time, diurnal) of extracted densities and inferred temperatures will be compared with corresponding 3-D Mars Global Ionosphere-Thermosphere Model (M-GITM) simulated outputs in order to understand the variations observed, and probe the underlying physical processes responsible. Solar rotation variations in EUV fluxes and their impacts on dayside temperatures will also be examined.

  2. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature

    NASA Astrophysics Data System (ADS)

    Gao, Ya; Hu, Jia-Mian; Nelson, C. T.; Yang, T. N.; Shen, Y.; Chen, L. Q.; Ramesh, R.; Nan, C. W.

    2016-03-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface.

  3. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature

    PubMed Central

    Gao, Ya; Hu, Jia-Mian; Nelson, C. T.; Yang, T. N.; Shen, Y.; Chen, L. Q.; Ramesh, R.; Nan, C. W.

    2016-01-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface. PMID:27029464

  4. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature.

    PubMed

    Gao, Ya; Hu, Jia-Mian; Nelson, C T; Yang, T N; Shen, Y; Chen, L Q; Ramesh, R; Nan, C W

    2016-01-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface. PMID:27029464

  5. In situ imaging and proteome profiling indicate andrographolide is a highly promiscuous compound

    NASA Astrophysics Data System (ADS)

    Li, Lin; Wijaya, Hadhi; Samanta, Sanjay; Lam, Yulin; Yao, Shao Q.

    2015-06-01

    Natural products represent an enormous source of pharmacologically useful compounds, and are often used as the starting point in modern drug discovery. Many biologically interesting natural products are however not being pursued as potential drug candidates, partly due to a lack of well-defined mechanism-of-action. Traditional in vitro methods for target identification of natural products based on affinity protein enrichment from crude cellular lysates cannot faithfully recapitulate protein-drug interactions in living cells. Reported herein are dual-purpose probes inspired by the natural product andrographolide, capable of both reaction-based, real-time bioimaging and in situ proteome profiling/target identification in live mammalian cells. Our results confirm that andrographolide is a highly promiscuous compound and engaged in covalent interactions with numerous previously unknown cellular targets in cell type-specific manner. We caution its potential therapeutic effects should be further investigated in detail.

  6. Melting of geomaterials under high-pressure using in-situ time-resolved XRD

    NASA Astrophysics Data System (ADS)

    Mezouar, M.; Dewaele, A.; Loubeyre, P.; Nicolas, G.; Garbarino, G.; Salamat, A.; Petitgirard, S.; Fiquet, G.

    2011-12-01

    Detailed knowledge of the high pressure melting relations is essential for constructing and validating models of materials behavior under extreme conditions for fields ranging from geophysics and planetary sciences to fundamental and applied physics. In the present work, melting and solid-solid phase transitions of several materials have been precisely followed using an original in-situ synchrotron time-resolved x-ray diffraction method. The real-time detection of the x-ray signal scattered by the liquid is used as an objective criterion for melting. The principle and potential of this method will be illustrated in three important cases, i.e. lead, and tantalum melting curves (physics) and the melting of peridotite (geophysics).

  7. In-situ nanoindentation specimen holder for a high-voltage transmission electron microscope

    SciTech Connect

    Dahmen; U; Wall, M A

    1998-09-17

    This report describes the design, construction, and testing of a nanoindentation specimen holder used for dynamic observation of subsurface microstructure evolution under an indenter tip, while viewing in cross-section in a high-voltage transmission electron microscope (TEM). It also discusses the initial experimental results from in-situ indentation of Si samples in the TEM to demonstrate the capability of this new nanoindentation specimen holder, which uses three-axis position control of a diamond indenter in combination with micromachined specimens. Additionally, the sample design techniques developed for these procedures may eliminate the need for TEM specimen preparation in future ex-situ nanoindentation experiments and for sample preparation for characterizing these experiments in the electron microscope.

  8. Production of complex nucleic acid libraries using highly parallel in situ oligonucleotide synthesis.

    PubMed

    Cleary, Michele A; Kilian, Kristopher; Wang, Yanqun; Bradshaw, Jeff; Cavet, Guy; Ge, Wei; Kulkarni, Amit; Paddison, Patrick J; Chang, Kenneth; Sheth, Nihar; Leproust, Eric; Coffey, Ernest M; Burchard, Julja; McCombie, W Richard; Linsley, Peter; Hannon, Gregory J

    2004-12-01

    Generation of complex libraries of defined nucleic acid sequences can greatly aid the functional analysis of protein and gene function. Previously, such studies relied either on individually synthesized oligonucleotides or on cellular nucleic acids as the starting material. As each method has disadvantages, we have developed a rapid and cost-effective alternative for construction of small-fragment DNA libraries of defined sequences. This approach uses in situ microarray DNA synthesis for generation of complex oligonucleotide populations. These populations can be recovered and either used directly or immortalized by cloning. From a single microarray, a library containing thousands of unique sequences can be generated. As an example of the potential applications of this technology, we have tested the approach for the production of plasmids encoding short hairpin RNAs (shRNAs) targeting numerous human and mouse genes. We achieved high-fidelity clone retrieval with a uniform representation of intended library sequences. PMID:15782200

  9. In-Situ Observation of Horizontal Centrifugal Casting using a High-Speed Camera

    NASA Astrophysics Data System (ADS)

    Esaka, Hisao; Kawai, Kohsuke; Kaneko, Hiroshi; Shinozuka, Kei

    2012-07-01

    In order to understand the solidification process of horizontal centrifugal casting, experimental equipment for in-situ observation using transparent organic substance has been constructed. Succinonitrile-1 mass% water alloy was filled in the round glass cell and the glass cell was completely sealed. To observe the movement of equiaxed grains more clearly and to understand the effect of movement of free surface, a high-speed camera has been installed on the equipment. The most advantageous point of this equipment is that the camera rotates with mold, so that one can observe the same location of the glass cell. Because the recording rate could be increased up to 250 frames per second, the quality of movie was dramatically modified and this made easier and more precise to pursue the certain equiaxed grain. The amplitude of oscillation of equiaxed grain ( = At) decreased as the solidification proceeded.

  10. In situ imaging and proteome profiling indicate andrographolide is a highly promiscuous compound.

    PubMed

    Li, Lin; Wijaya, Hadhi; Samanta, Sanjay; Lam, Yulin; Yao, Shao Q

    2015-01-01

    Natural products represent an enormous source of pharmacologically useful compounds, and are often used as the starting point in modern drug discovery. Many biologically interesting natural products are however not being pursued as potential drug candidates, partly due to a lack of well-defined mechanism-of-action. Traditional in vitro methods for target identification of natural products based on affinity protein enrichment from crude cellular lysates cannot faithfully recapitulate protein-drug interactions in living cells. Reported herein are dual-purpose probes inspired by the natural product andrographolide, capable of both reaction-based, real-time bioimaging and in situ proteome profiling/target identification in live mammalian cells. Our results confirm that andrographolide is a highly promiscuous compound and engaged in covalent interactions with numerous previously unknown cellular targets in cell type-specific manner. We caution its potential therapeutic effects should be further investigated in detail. PMID:26105662

  11. In situ imaging and proteome profiling indicate andrographolide is a highly promiscuous compound

    PubMed Central

    Li, Lin; Wijaya, Hadhi; Samanta, Sanjay; Lam, Yulin; Yao, Shao Q.

    2015-01-01

    Natural products represent an enormous source of pharmacologically useful compounds, and are often used as the starting point in modern drug discovery. Many biologically interesting natural products are however not being pursued as potential drug candidates, partly due to a lack of well-defined mechanism-of-action. Traditional in vitro methods for target identification of natural products based on affinity protein enrichment from crude cellular lysates cannot faithfully recapitulate protein-drug interactions in living cells. Reported herein are dual-purpose probes inspired by the natural product andrographolide, capable of both reaction-based, real-time bioimaging and in situ proteome profiling/target identification in live mammalian cells. Our results confirm that andrographolide is a highly promiscuous compound and engaged in covalent interactions with numerous previously unknown cellular targets in cell type-specific manner. We caution its potential therapeutic effects should be further investigated in detail. PMID:26105662

  12. Synthesis and characterization of an in situ forming hydrogel using tyramine conjugated high methoxyl gum tragacanth.

    PubMed

    Tavakol, Moslem; Vasheghani-Farahani, Ebrahim; Mohammadifar, Mohammad Amin; Soleimani, Masoud; Hashemi-Najafabadi, Sameereh

    2016-02-01

    In this study, an enzyme catalyzed in situ forming hydrogel based on tyramine conjugated high methoxyl content gum tragacanth (TA-HMGT) was prepared and characterized. TA-HMGT was synthesized via heterogeneous ammonolysis of methyl ester groups of HMGT. Then, the hydrogel was prepared via horseradish peroxidase catalyzed coupling reaction in the presence of hydrogen peroxide. Hydrogel properties, such as gelation time, swelling/degradation behavior and rheological properties could be adjusted by tuning the gelation parameters and extent of tyramine conjugation. This system was a soft elastic hydrogel with appropriate biocompatibility. The fast gelation of the hydrogel is desirable for clinical applications. Also, in vitro bovine serum albumin release from the synthesized hydrogel showed good release profile with limited burst release. PMID:26553882

  13. Temperature Assisted in-Situ Small Angle X-ray Scattering Analysis of Ph-POSS/PC Polymer Nanocomposite

    PubMed Central

    Yadav, Ramdayal; Naebe, Minoo; Wang, Xungai; Kandasubramanian, Balasubramanian

    2016-01-01

    Inorganic/organic nanofillers have been extensively exploited to impart thermal stability to polymer nanocomposite via various strategies that can endure structural changes when exposed a wide range of thermal environment during their application. In this abstraction, we have utilized temperature assisted in-situ small angle X-ray scattering (SAXS) to examine the structural orientation distribution of inorganic/organic nanofiller octa phenyl substituted polyhedral oligomeric silsesquioxane (Ph-POSS) in Polycarbonate (PC) matrix from ambient temperature to 180 °C. A constant interval of 30 °C with the heating rate of 3 °C/min was utilized to guise the temperature below and above the glass transition temperature of PC followed by thermal gravimetric, HRTEM, FESEM and hydrophobic analysis at ambient temperature. The HRTEM images of Ph-POSS nano unit demonstrated hyperrectangular structure, while FESEM image of the developed nano composite rendered separated phase containing flocculated and overlapped stacking of POSS units in the PC matrix. The phase separation in polymer nanocomposite was further substantiated by thermodynamic interaction parameter (χ) and mixing energy (Emix) gleaned via Accelrys Materials studio. The SAXS spectra has demonstrated duplex peak at higher scattering vector region, postulated as a primary and secondary segregated POSS domain and followed by abundance of secondary peak with temperature augmentation. PMID:27436152

  14. In situ H2O and temperature detection close to burning biomass pellets using calibration-free wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Qu, Zhechao; Schmidt, Florian M.

    2015-04-01

    The design and application of an H2O/temperature sensor based on scanned calibration-free wavelength modulation spectroscopy (CF-WMS) and a single tunable diode laser at 1.4 µm is presented. The sensor probes two H2O absorption peaks in a single scan and simultaneously retrieves H2O concentration and temperature by least-squares fitting simulated 1f-normalized 2f-WMS spectra to measured 2f/ 1f-WMS signals, with temperature, concentration and nonlinear modulation amplitude as fitting parameters. Given a minimum detectable absorbance of 1.7 × 10-5 cm-1 Hz-1/2, the system is applicable down to an H2O concentration of 0.1 % at 1,000 K and 20 cm path length (200 ppm·m). The temperature in a water-seeded laboratory-scale reactor (670-1220 K at 4 % H2O) was determined within an accuracy of 1 % by comparison with the reactor thermocouple. The CF-WMS sensor was applied to real time in situ measurements of H2O concentration and temperature time histories (0.25-s time resolution) in the hot gases 2-11 mm above biomass pellets during atmospheric combustion in the reactor. Temperatures between 1,200 and 1,600 K and H2O concentrations up to 40 % were detected above the biofuels.

  15. Temperature Assisted in-Situ Small Angle X-ray Scattering Analysis of Ph-POSS/PC Polymer Nanocomposite

    NASA Astrophysics Data System (ADS)

    Yadav, Ramdayal; Naebe, Minoo; Wang, Xungai; Kandasubramanian, Balasubramanian

    2016-07-01

    Inorganic/organic nanofillers have been extensively exploited to impart thermal stability to polymer nanocomposite via various strategies that can endure structural changes when exposed a wide range of thermal environment during their application. In this abstraction, we have utilized temperature assisted in-situ small angle X-ray scattering (SAXS) to examine the structural orientation distribution of inorganic/organic nanofiller octa phenyl substituted polyhedral oligomeric silsesquioxane (Ph-POSS) in Polycarbonate (PC) matrix from ambient temperature to 180 °C. A constant interval of 30 °C with the heating rate of 3 °C/min was utilized to guise the temperature below and above the glass transition temperature of PC followed by thermal gravimetric, HRTEM, FESEM and hydrophobic analysis at ambient temperature. The HRTEM images of Ph-POSS nano unit demonstrated hyperrectangular structure, while FESEM image of the developed nano composite rendered separated phase containing flocculated and overlapped stacking of POSS units in the PC matrix. The phase separation in polymer nanocomposite was further substantiated by thermodynamic interaction parameter (χ) and mixing energy (Emix) gleaned via Accelrys Materials studio. The SAXS spectra has demonstrated duplex peak at higher scattering vector region, postulated as a primary and secondary segregated POSS domain and followed by abundance of secondary peak with temperature augmentation.

  16. Temperature Assisted in-Situ Small Angle X-ray Scattering Analysis of Ph-POSS/PC Polymer Nanocomposite.

    PubMed

    Yadav, Ramdayal; Naebe, Minoo; Wang, Xungai; Kandasubramanian, Balasubramanian

    2016-01-01

    Inorganic/organic nanofillers have been extensively exploited to impart thermal stability to polymer nanocomposite via various strategies that can endure structural changes when exposed a wide range of thermal environment during their application. In this abstraction, we have utilized temperature assisted in-situ small angle X-ray scattering (SAXS) to examine the structural orientation distribution of inorganic/organic nanofiller octa phenyl substituted polyhedral oligomeric silsesquioxane (Ph-POSS) in Polycarbonate (PC) matrix from ambient temperature to 180 °C. A constant interval of 30 °C with the heating rate of 3 °C/min was utilized to guise the temperature below and above the glass transition temperature of PC followed by thermal gravimetric, HRTEM, FESEM and hydrophobic analysis at ambient temperature. The HRTEM images of Ph-POSS nano unit demonstrated hyperrectangular structure, while FESEM image of the developed nano composite rendered separated phase containing flocculated and overlapped stacking of POSS units in the PC matrix. The phase separation in polymer nanocomposite was further substantiated by thermodynamic interaction parameter (χ) and mixing energy (Emix) gleaned via Accelrys Materials studio. The SAXS spectra has demonstrated duplex peak at higher scattering vector region, postulated as a primary and secondary segregated POSS domain and followed by abundance of secondary peak with temperature augmentation. PMID:27436152

  17. EXPERIMENTAL INVESTIGATION AND HIGH RESOLUTION SIMULATOR OF IN-SITU COMBUSTION PROCESSES

    SciTech Connect

    Margot Gerritsen; Anthony R. Kovscek

    2005-02-01

    Accurate simulation of in-situ combustion processes is computationally very challenging because the spatial and temporal scales over which the combustion process takes place are very small. In this fifth quarterly report of our DoE funded research, we continue the discussion of the design of a new simulation tool based on an efficient Cartesian Adaptive Mesh Refinement technique that allows much higher grid densities to be used near typical fronts than current simulators. We have now developed an appropriate upscaling technique for our grids, based on the local-global upscaling approach. We show preliminary results on two-dimensional test cases. On the experimental side, we continued experiments to measure the rates and kinetics of combustion in the presence and absence of metallic additives. In this quarter, we developed a better understanding of the cation replacing power of the various additives that affect combustion performance positively, and obtained a preliminary reactivity series. We also resumed our experimental investigation into the cyclic solvent-combustion process using crude oil from the Hamaca Region of Venezuela. Various measurements were made including oxygen consumption as a function of temperature. Preliminary results show that the temperatures for the onset of combustion are a function of the solvent injected.

  18. Stimulating in situ denitrification in an aerobic, highly permeable municipal drinking water aquifer

    NASA Astrophysics Data System (ADS)

    Critchley, K.; Rudolph, D. L.; Devlin, J. F.; Schillig, P. C.

    2014-12-01

    A preliminary trial of a cross-injection system (CIS) was designed to stimulate in situ denitrification in an aquifer servicing an urban community in southern Ontario. It was hypothesized that this remedial strategy could be used to reduce groundwater nitrate in the aquifer such that it could remain in use as a municipal supply until the beneficial effects of local reduced nutrient loadings lead to long-term water quality improvement at the wellfield. The CIS application involved injecting a carbon source (acetate) into the subsurface using an injection-extraction well pair positioned perpendicular to the regional flow direction, up-gradient of the water supply wells, with the objective of stimulating native denitrifying bacteria. The pilot remedial strategy was targeted in a high nitrate flux zone within an aerobic and heterogeneous section of the glacial sand and gravel aquifer. Acetate injections were performed at intervals ranging from daily to bi-daily. The carbon additions led to general declines in dissolved oxygen concentrations; decreases in nitrate concentration were localized in aquifer layers where velocities were estimated to be less than 0.5 m/day. NO3-15N and NO3-18O isotope data indicated the nitrate losses were due to denitrification. Relatively little nitrate was removed from groundwater in the more permeable strata, where velocities were estimated to be on the order of 18 m/day or greater. Overall, about 11 percent of the nitrate mass passing through the treatment zone was removed. This work demonstrates that stimulating in situ denitrification in an aerobic, highly conductive aquifer is challenging but achievable. Further work is needed to increase rates of denitrification in the most permeable units of the aquifer.

  19. A System to Measure Both Inner and Outer Car Tire Temperatures ``in situ''

    NASA Astrophysics Data System (ADS)

    Koštial, P.; Mokryšová, M.; Šišáková, J.; Mošková, Z.; Rusnáková, S.

    2009-02-01

    In the paper, a system for the complex analysis of the internal and external tire temperatures and pressure of sporty tires is presented. Tests were performed on the test circuit of a tire producer. The CTPA 05 measuring system (complex temperature-pressure analyzer) enables simultaneous measurements of the internal temperature and pressure in a passenger or sports tire. The experimentalist determines that the CTPA 05 can be used to measure independently the external temperature of the overcoat on the front wheel driving tires at three points. Measurements of both the internal tire temperature and pressure, as well as of the external tire temperature, are collected together with GPS (global position system) data. The system of measurement is fully automatic and contactless. The obtained results are in very good agreement with those obtained by independent methods.

  20. Evaluating high resolution GRACE solutions against in situ measurements in the Three-Gorge Reservoir

    NASA Astrophysics Data System (ADS)

    De Linage, C.; Bettadpur, S.; Famiglietti, J. S.

    2012-12-01

    Wang et al (2011) showed that, when compared to in situ data, the total volume change associated with the impoundment of the Three-Gorge Reservoir between April 2002 and May 2010 could be retrieved with a 3-km3 (14%) error by the GRACE-CSR Release 04 solutions at 3.5° (max. harmonic degree 51) resolution after correlated errors were removed. However, the retrieved total volume change suffered from low spatial resolution and incorrect spatial localization. A larger volume increase was found in GRACE compared to in situ data during the last impoundment which was attributable to seepage into the underlying aquifer. In this study, we analyze the new CSR-Release 05 monthly solutions for 2004-2010. We also generate high resolution (1°, max. degree 180) mean solutions computed before and after the first and last impoundments for both Release 04 and Release 05. Correlated errors are removed using the decorrelation filter suggested by Swenson and Wahr (2006). We find a better agreement with RL05 (r2=0.66, MAD=4.30 km3) than with RL04 monthly solutions (r2=0.50, MAD=4.95 km3), and find even larger volume increase during the last impoundment (5-8 km3 difference vs 4-6 km3), strengthening our initial hypothesis of groundwater recharge. We find that 1° resolution mean solutions need to be truncated at max. degree 80 (2.5°) to reduce the impact of noise. A better spatial concentration is then obtained although the total volume change is now underestimated compared to in situ data. Finally, the damping effect of the decorrelation filter is investigated by forward modeling of total volume change using the 3" SRTM DEM. As an alternative, we apply the spatio-spectral localization technique based on Slepian functions (Simons 2006) to improve the signal-to-noise ratio. The contribution of regional hydrology is also considered via global hydrological model predictions.

  1. In Situ Polymerization and Characterization of Highly Conducting Polypyrrole Fish Scales for High-Frequency Applications

    NASA Astrophysics Data System (ADS)

    Velhal, Ninad B.; Patil, Narayan D.; Puri, Vijaya R.

    2015-12-01

    Polypyrrole (Ppy) thin films on alumina were synthesized by an in situ chemical oxidative polymerization method at 300 K with equal monomer-to-oxidant ratio. Fourier transform infrared spectroscopy (FTIR) and FT-Raman spectroscopy confirmed the formation of Ppy. A thickness-dependent change from cauliflower to fish-scale morphology was observed. Microwave properties such as transmission, reflection, shielding effectiveness, permittivity, and microwave conductivity are reported in the frequency range from 8 GHz to 12 GHz. The direct-current (DC) conductivity varied from 9.45 × 10-3 S/cm to 17.29 × 10-3 S/cm, whereas the microwave conductivity varied from 63.07 S/cm to 349.08 S/cm. The shielding effectiveness varied between 6.18 dB and 10.39 dB.

  2. High-Temperature Lubricants

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the early 1980's, Lewis Research Center began a program to develop high-temperature lubricants for use on future aircraft flying at three or more times the speed of sound, which can result in vehicle skin temperatures as high as 1,600 degrees Fahrenheit. A material that emerged from this research is a plasma-sprayed, self-lubricating metal- glass-fluoride coating able to reduce oxidation at very high temperatures. Technology is now in commercial use under the trade name Surf-Kote C-800, marketed by Hohman Plating and Manufacturing Inc. and manufactured under a patent license from NASA. Among its uses are lubrication for sliding contact bearings, shaft seals for turbopumps, piston rings for high performance compressors and hot glass processing machinery; it is also widely used in missile and space applications.

  3. High temperature hydraulic seals

    NASA Astrophysics Data System (ADS)

    Williams, K. R.

    1993-05-01

    This program investigated and evaluated high temperature hydraulic sealing technology, including seals, fluids, and actuator materials. Test limits for fluid pressure and temperature were 8000 psi and 700 F respectively. The original plan to investigate CTFE fluid at 350 F as well as other fluids at higher temperatures was reduced in scope to include only the higher temperature investigation. Seals were obtained from 11 manufacturers. Design requirements including materials, dimensions, clearances, and tolerances were established and test modules were constructed from the detail designs which were produced. Nine piston seals and one rod seal were tested at temperatures ranging from -65 to +600 F and pressures to 6000 psi. Fluid performance under these conditions was evaluated. Details of this activity and results of the effort are summarized in this report.

  4. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    PubMed Central

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-01-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost. PMID:26631685

  5. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells.

    PubMed

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-01-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost. PMID:26631685

  6. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-12-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost.

  7. Real time, in-situ temperature monitoring using diffuse reflectance spectroscopy

    SciTech Connect

    Booth, J.L.; Beard, B.T.; Pearsall, T.P.; Wang, Z.Z.; Stevens, J.E.; Blain, M.G.; Meisenheimer, T.L.

    1996-11-01

    Real time temperature measurements have been performed on both GaAs and silicon substrates during wafer processing using a technique based upon diffuse reflectance spectroscopy (DRS). Good temperature resolution ({+-}O.4 {degrees}C) and rapid updates have enabled the process control potential of the device to be demonstrated.

  8. Highly textured fresnoite thin films synthesized in situ by pulsed laser deposition with CO2 laser direct heating

    NASA Astrophysics Data System (ADS)

    Lorenz, Michael; de Pablos-Martin, Araceli; Patzig, Christian; Stölzel, Marko; Brachwitz, Kerstin; Hochmuth, Holger; Grundmann, Marius; Höche, Thomas

    2014-01-01

    Fresnoite Ba2TiSi2O8 (BTS) thin films were grown and crystallized in situ using pulsed laser deposition (PLD) with CO2 laser direct heating of the a-plane sapphire (1 1 0) substrates up to 1250 °C. Starting with 775 °C growth temperature, (0 0 1)- and (1 1 0)-textured BTS and BaTiO3 phases, respectively, could be assigned in the films, and the typical fern-like BTS crystallization patterns appear. For higher process temperatures of 1100 to 1250 °C, atomically smooth, terraced surface of the films was found, accompanied by crystalline high-temperature phases of Ba-Ti-Si oxides. HAADF micrographs taken in both scanning transmission electron microscopy and energy-dispersive x-ray spectrometry mode show details of morphology and elemental distribution inside the films and at the interface. To balance the inherent Si deficiency of the BTS films, growth from glassy BTS × 2 SiO2 and BTS × 2.5 SiO2 targets was considered as well. The latter targets are ideal for PLD since the employed glasses possess 100% of the theoretical density and are homogeneous at the atomic scale.

  9. In-situ measurements of neutral temperature in the middle atmosphere by using electrons as proxy

    NASA Astrophysics Data System (ADS)

    Svenes, K. R.; Blix, T. A.; Hoppe, U.-P.; Gumbel, J.; Strelnikov, B.

    2005-08-01

    We have developed a new rocket-borne electron probe for measurements of electron temperature in the mesosphere and lower thermosphere. The technique is based on the assumption that a thermal equilibrium between electrons and neutrals exists in this region. We can then determine the neutral air temperature with a height resolution of a few hundred meters. Here, we present the measurement principle and the method of converting the measured electron temperature to neutral temperature. Since effects of the supersonically moving payload influence on the measurements, this must be accounted for accordingly in the conversion procedure. For this purpose we have performed aerodynamic simulations to characterize the flow around the probe, and we apply this to the temperature conversion. Data from a flight conducted from Ny-Ålesund, Svalbard in July 2003 has been used to test the method, and the first results will be presented here.

  10. High-pressure behavior and thermoelastic properties of niobium studied by in situ x-ray diffraction

    SciTech Connect

    Zou, Yongtao E-mail: yongtaozou6@gmail.com; Li, Baosheng; Qi, Xintong; Wang, Xuebing; Chen, Ting; Li, Xuefei; Welch, David

    2014-07-07

    In situ synchrotron energy dispersive x-ray diffraction (XRD) experiments on Nb have been conducted at pressures up to 6.4 GPa and temperatures up to 1073 K. From the pressure-volume-temperature measurements, thermoelastic parameters were derived for the first time for Nb based on the thermal pressure (ΔP{sub th}) equation of state (EOS), modified high-T Birch-Murnaghan EOS, and Mie-Grüneisen-Debye EOS. With the pressure derivative of the bulk modulus K{sub T}{sup ´} fixed at 4.0, we obtained the ambient isothermal bulk modulus K{sub T0}=174(5) GPa, the temperature derivative of bulk modulus at constant pressure (∂K{sub T}/∂T){sub P}=-0.060(8) GPa K⁻¹ and at constant volume (∂K{sub T}/∂T){sub V}=-0.046(8) GPa K⁻¹, the volumetric thermal expansivity α{sub T}(T)=2.3(3)×10⁻⁵+0.3(2)×10⁻⁸T (K⁻¹), as well as the pressure dependence of thermal expansion (∂α/∂P){sub T}=(₋2.0±0.4)×10⁻⁶ K⁻¹ GPa⁻¹. Fitting the present data to the Mie-Grüneisen-Debye EOS with Debye temperature Θ₀=276.6 K gives γ₀=1.27(8) and K{sub T0}=171(3) GPa at a fixed value of q=3.0. The ambient isothermal bulk modulus and Grüneisen parameter derived from this work are comparable to previously reported values from both experimental and theoretical studies. An in situ high-resolution, angle dispersive XRD study on Nb did not indicate any anomalous behavior related to pressure-induced electronic topological transitions at ~5 GPa as has been reported previously.

  11. Seeing the light: the effects of particles, dissolved materials, and temperature on in situ measurements of DOM fluorescence in rivers and streams

    USGS Publications Warehouse

    Downing, Bryan D.; Pellerin, Brian A.; Bergamaschi, Brian A.; Saraceno, John Franco; Kraus, Tamara E.C.

    2012-01-01

    Field-deployable sensors designed to continuously measure the fluorescence of colored dissolved organic matter (FDOM) in situ are of growing interest. However, the ability to make FDOM measurements that are comparable across sites and over time requires a clear understanding of how instrument characteristics and environmental conditions affect the measurements. In particular, the effects of water temperature and light attenuation by both colored dissolved material and suspended particles may be significant in settings such as rivers and streams. Using natural standard reference materials, we characterized the performance of four commercially-available FDOM sensors under controlled laboratory conditions over ranges of temperature, dissolved organic matter (DOM) concentrations, and turbidity that spanned typical environmental ranges. We also examined field data from several major rivers to assess how often attenuation artifacts or temperature effects might be important. We found that raw (uncorrected) FDOM values were strongly affected by the light attenuation that results from dissolved substances and suspended particles as well as by water temperature. Observed effects of light attenuation and temperature agreed well with theory. Our results show that correction of measured FDOM values to account for these effects is necessary and feasible over much of the range of temperature, DOM concentration, and turbidity commonly encountered in surface waters. In most cases, collecting high-quality FDOM measurements that are comparable through time and between sites will require concurrent measurements of temperature and turbidity, and periodic discrete sample collection for laboratory measurement of DOM.

  12. High Refractive Index Polysiloxane as Injectable, In Situ Curable Accommodating Intraocular Lens

    PubMed Central

    Hao, Xiaojuan; Jeffery, Justine L.; Le, Tam P.T.; McFarland, Gail; Johnson, Graham; Mulder, Roger J.; Garrett, Qian; Manns, Fabrice; Nankivil, Derek; Arrieta, Esdras; Ho, Arthur; Parel, Jean-Marie; Hughes, Timothy C.

    2012-01-01

    Functionalised siloxane macromonomers, with properties designed for application as an injectable, in situ curable accommodating intraocular lens (A-IOL), were prepared via reequilibration of a phenyl group-containing polysiloxane of very high molecular weight with octamethylcyclotetrasiloxane (D4) and 2,4,6,8-tetra(n-propyl-3-methacrylate)-2,4,6,8-tetramethylcyclotetrasiloxane (D4AM) in toluene using trifluoromethanesulfonic acid as a catalyst. Hexaethyldisiloxane was used as an end group to control the molecular weight of the polymer. The generated polymers had a consistency suitable for injection into the empty lens capsule. The polymers contained a low ratio of polymerisable groups so that, in the presence of a photo-initiator, they could be cured on demand in situ within 5 minutes under irradiation of blue light to form an intraocular lens within the lens capsule. All resulting polysiloxane soft gels had a low elastic modulus and thus should be able to restore accommodation. The pre-cure viscosity and post-cure modulus of the generated polysiloxanes were controlled by the end group and D4AM concentrations respectively in the re-equilibration reactions. The refractive index could be precisely controlled by adjusting the aromatic ratio in the polymer to suit such application as an artificial lens. Lens stretching experiments with both human and non-human primate cadaver lenses of different ages refilled with polysiloxane polymers provided a significant increase in amplitude of accommodation (up to 4 D more than that of the respective natural lens). Both in vitro cytotoxicity study using L929 cell lines and in vivo biocompatibility study in rabbit models demonstrated the non-cytotoxicity and ocular biocompatibility of the polymer. PMID:22594975

  13. EQUILGAS: Program to estimate temperatures and in situ two-phase conditions in geothermal reservoirs using three combined FT-HSH gas equilibria models

    NASA Astrophysics Data System (ADS)

    Barragán, Rosa María; Núñez, José; Arellano, Víctor Manuel; Nieva, David

    2016-03-01

    Exploration and exploitation of geothermal resources require the estimation of important physical characteristics of reservoirs including temperatures, pressures and in situ two-phase conditions, in order to evaluate possible uses and/or investigate changes due to exploitation. As at relatively high temperatures (>150 °C) reservoir fluids usually attain chemical equilibrium in contact with hot rocks, different models based on the chemistry of fluids have been developed that allow deep conditions to be estimated. Currently either in water-dominated or steam-dominated reservoirs the chemistry of steam has been useful for working out reservoir conditions. In this context, three methods based on the Fischer-Tropsch (FT) and combined H2S-H2 (HSH) mineral-gas reactions have been developed for estimating temperatures and the quality of the in situ two-phase mixture prevailing in the reservoir. For these methods the mineral buffers considered to be controlling H2S-H2 composition of fluids are as follows. The pyrite-magnetite buffer (FT-HSH1); the pyrite-hematite buffer (FT-HSH2) and the pyrite-pyrrhotite buffer (FT-HSH3). Currently from such models the estimations of both, temperature and steam fraction in the two-phase fluid are obtained graphically by using a blank diagram with a background theoretical solution as reference. Thus large errors are involved since the isotherms are highly nonlinear functions while reservoir steam fractions are taken from a logarithmic scale. In order to facilitate the use of the three FT-HSH methods and minimize visual interpolation errors, the EQUILGAS program that numerically solves the equations of the FT-HSH methods was developed. In this work the FT-HSH methods and the EQUILGAS program are described. Illustrative examples for Mexican fields are also given in order to help the users in deciding which method could be more suitable for every specific data set.

  14. In-situ ellipsometric studies of optical and surface properties of GaAs(100) at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Yao, Huade; Snyder, Paul G.

    1991-01-01

    A rotating-polarizer ellipsometer was attached to an ultrahigh vacuum (UHV) chamber. A GaAs(100) sample was introduced into the UHV chamber and heated at anumber of fixed elevated temperatures, without arsenic overpressure. In-situ spectroscopic ellipsometric (SE) measurements were taken, through a pair of low-strain quartz windows, to monitor the surface changes and measure the pseudodielectric functions at elevated temperatures. Real-time data from GaAs surface covered with native oxide showed clearly the evolution of oxide desorption at approximately 580 C. In addition, surface degradation was found before and after the oxide desorption. An oxide free and smooth GaAs surface was obtained by depositing an arsenic protective coating onto a molecular beam epitaxy grown GaAs surface. The arsenic coating was evaporated immediately prior to SE measurements. A comparison showed that our room temperature data from this GaAs surface, measured in the UHV, are in good agreement with those in the literature obtained by wet-chemical etching. The surface also remained clean and smooth at higher temperatures, so that reliable temperature-dependent dielectric functions were obtained.

  15. In situ temperature measurements of reaction spaces under microwave irradiation using photoluminescent probes.

    PubMed

    Ano, Taishi; Kishimoto, Fuminao; Sasaki, Ryo; Tsubaki, Shuntaro; Maitani, Masato M; Suzuki, Eiichi; Wada, Yuji

    2016-05-11

    We demonstrate two novel methods for the measurement of the temperatures of reaction spaces locally heated by microwaves, which have been applied here to two example systems, i.e., BaTiO3 particles covered with a SiO2 shell (BaTiO3-SiO2) and layered tungstate particles. Photoluminescent (PL) probes showing the temperature-sensitivity in their PL lifetimes are located in the nanospaces of the above systems. In the case of BaTiO3-SiO2 core-shell particles, rhodamine B is loaded into the mesopores of the SiO2 shell covering the BaTiO3 core, which generates the heat through the dielectric loss of microwaves. The inner nanospace temperature of the SiO2 shell is determined to be 28 °C higher than the bulk temperature under microwave irradiation at 24 W. On the other hand, Eu(3+) is immobilized in the interlayer space of layered tungstate as the PL probe, showing that the nanospace temperature of the interlayer is only 4 °C higher than the bulk temperature. This method for temperature-measurement is powerful for controlling microwave heating and elucidates the ambiguous mechanisms of microwave special effects often observed in chemical reactions, contributing greatly to the practical application of microwaves in chemistry and materials sciences. PMID:27136754

  16. In-Situ Acoustic Measurements of Temperature Profile in Extreme Environments

    SciTech Connect

    Skliar, Mikhail

    2015-03-31

    A gasifier’s temperature is the primary characteristic that must be monitored to ensure its performance and the longevity of its refractory. One of the key technological challenges impacting the reliability and economics of coal and biomass gasification is the lack of temperature sensors that are capable of providing accurate, reliable, and long-life performance in an extreme gasification environment. This research has proposed, demonstrated, and validated a novel approach that uses a noninvasive ultrasound method that provides real-time temperature distribution monitoring across the refractory, especially the hot face temperature of the refractory. The essential idea of the ultrasound measurements of segmental temperature distribution is to use an ultrasound propagation waveguide across a refractory that has been engineered to contain multiple internal partial reflectors at known locations. When an ultrasound excitation pulse is introduced on the cold side of the refractory, it will be partially reflected from each scatterer in the US propagation path in the refractory wall and returned to the receiver as a train of partial echoes. The temperature in the corresponding segment can be determined based on recorded ultrasonic waveform and experimentally defined relationship between the speed of sound and temperature. The ultrasound measurement method offers a powerful solution to provide continuous real time temperature monitoring for the occasions that conventional thermal, optical and other sensors are infeasible, such as the impossibility of insertion of temperature sensor, harsh environment, unavailable optical path, and more. Our developed ultrasound system consists of an ultrasound engineered waveguide, ultrasound transducer/receiver, and data acquisition, logging, interpretation, and online display system, which is simple to install on the existing units with minimal modification on the gasifier or use with new units. This system has been successfully tested

  17. Preparation of high temperature gas-cooled reactor fuel element

    DOEpatents

    Bradley, Ronnie A.; Sease, John D.

    1976-01-01

    This invention relates to a method for the preparation of high temperature gas-cooled reactor (HTGR) fuel elements wherein uncarbonized fuel rods are inserted in appropriate channels of an HTGR fuel element block and the entire block is inserted in an autoclave for in situ carbonization under high pressure. The method is particularly applicable to remote handling techniques.

  18. A furnace and environmental cell for the in situ investigation of molten salt electrolysis using high-energy X-ray diffraction.

    PubMed

    Styles, Mark J; Rowles, Matthew R; Madsen, Ian C; McGregor, Katherine; Urban, Andrew J; Snook, Graeme A; Scarlett, Nicola V Y; Riley, Daniel P

    2012-01-01

    This paper describes the design, construction and implementation of a relatively large controlled-atmosphere cell and furnace arrangement. The purpose of this equipment is to facilitate the in situ characterization of materials used in molten salt electrowinning cells, using high-energy X-ray scattering techniques such as synchrotron-based energy-dispersive X-ray diffraction. The applicability of this equipment is demonstrated by quantitative measurements of the phase composition of a model inert anode material, which were taken during an in situ study of an operational Fray-Farthing-Chen Cambridge electrowinning cell, featuring molten CaCl(2) as the electrolyte. The feasibility of adapting the cell design to investigate materials in other high-temperature environments is also discussed. PMID:22186642

  19. Low toxicity high temperature PMR polyimide

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor)

    1992-01-01

    In-situ polymerization of monomer reactants (PMR) type polyimides constitute an important class of ultra high performance composite matrix resins. PMR-15 is the best known and most widely used PMR polyimide. An object of the present invention is to provide a substantially improved high temperature PMR-15 system that exhibits better processability, toughness, and thermo-oxidative stability than PMR-15, as well as having a low toxicity. Another object is to provide new PMR polyimides that are useful as adhesives, moldings, and composite matrices. By the present invention, a new PMR polyimide comprises a mixture of the following compounds: 3,4'-oxydianiline (3,4'-ODA), NE, and BTDE which are then treated with heat. This PMR was designated LaRC-RP46 and has a broader processing window, better reproducibility of high quality composite parts, better elevated temperature mechanical properties, and higher retention of mechanical properties at an elevated temperature, particularly, at 371 C.

  20. A simple method for in situ monitoring of water temperature in substrates used by spawning salmonids

    USGS Publications Warehouse

    Zimmerman, Christian E.; Finn, James E.

    2012-01-01

    Interstitial water temperature within spawning habitats of salmonids may differ from surface-water temperature depending on intragravel flow paths, geomorphic setting, or presence of groundwater. Because survival and developmental timing of salmon are partly controlled by temperature, monitoring temperature within gravels used by spawning salmonids is required to adequately describe the environment experienced by incubating eggs and embryos. Here we describe a simple method of deploying electronic data loggers within gravel substrates with minimal alteration of the natural gravel structure and composition. Using data collected in spawning sites used by summer and fall chum salmon Oncorhynchus keta from two streams within the Yukon River watershed, we compare contrasting thermal regimes to demonstrate the utility of this method.

  1. Low temperature engineering applied to lunar in-situ resource utilization

    NASA Technical Reports Server (NTRS)

    Zhang, Burt; Chui, Talso; Croonquist, Arvid

    2005-01-01

    In support of NASA's Exploration Mission low-temperature scientists and engineers have investigated the process of extracting volatile materials from the lunar regolith, their purification/liquefaction, and storage.

  2. Determination of Warm Working Temperature Range for In Situ Alm-TiB2p Composite

    NASA Astrophysics Data System (ADS)

    Mishra, R.; Alexander, A.; Srinivasan, K.

    2015-04-01

    Composites with hard undeformable particles are better suited for creep resistant applications. Alm-TiB2 particulate composite is one such composite. Its flow properties and formability are investigated and presented in the paper. A suitable temperature range for working this particulate composite is ascertained by using uniaxial axysymmetric compression tests and ring compression tests. Warm working is found to be suitable for this composite in the temperature window of 473-523 K.

  3. Validating Satellite-Derived Land Surface Temperature with in Situ Measurements: A Public Health Perspective

    PubMed Central

    Brines, Shannon J.; Brown, Daniel G.; Dvonch, J. Timothy; Gronlund, Carina J.; Zhang, Kai; Oswald, Evan M.; O’Neill, Marie S.

    2013-01-01

    Background: Land surface temperature (LST) and percent surface imperviousness (SI), both derived from satellite imagery, have been used to characterize the urban heat island effect, a phenomenon in which urban areas are warmer than non-urban areas. Objectives: We aimed to assess the correlations between LSTs and SI images with actual temperature readings from a ground-based network of outdoor monitors. Methods: We evaluated the relationships among a) LST calculated from a 2009 summertime satellite image of the Detroit metropolitan region, Michigan; b) SI from the 2006 National Land Cover Data Set; and c) ground-based temperature measurements monitored during the same time period at 19 residences throughout the Detroit metropolitan region. Associations between these ground-based temperatures and the average LSTs and SI at different radii around the point of the ground-based temperature measurement were evaluated at different time intervals. Spearman correlation coefficients and corresponding p-values were calculated. Results: Satellite-derived LST and SI values were significantly correlated with 24-hr average and August monthly average ground temperatures at all but two of the radii examined (100 m for LST and 0 m for SI). Correlations were also significant for temperatures measured between 0400 and 0500 hours for SI, except at 0 m, but not LST. Statistically significant correlations ranging from 0.49 to 0.91 were observed between LST and SI. Conclusions: Both SI and LST could be used to better understand spatial variation in heat exposures over longer time frames but are less useful for estimating shorter-term, actual temperature exposures, which can be useful for public health preparedness during extreme heat events. PMID:23777856

  4. In Situ Visualization of Tears on Contact Lens Using Ultra High Resolution Optical Coherence Tomography

    PubMed Central

    Wang, Jianhua; Jiao, Shuliang; Ruggeri, Marco; Shousha, Mohammed Abou; Chen, Qi

    2012-01-01

    Objective To demonstrate the capability of directly visualizing the tear film on contact lenses using optical coherence tomography (OCT). Methods Six eyes of three healthy subjects wearing PureVision and ACUVUE Advance soft and Boston RGP hard contact lenses were imaged with a custom built, high speed, ultra-high resolution spectral domain optical coherence tomograph. Refresh Liquigel was used to demonstrate the effect of artificial tears on the tear film. Results Ultra high resolution images of the pre- and post-lens films were directly visualized when each lens was inserted onto the eye. After the instillation of artificial tears during lens wear, the tear film was thicker. The post-lens tear film underneath the lens edge was clearly shown. Interactions between the lens edges and the ocular surface were obtained for each of the lens types and base curves. With a contrast enhancement agent, tear menisci on the contact lenses around the upper and lower eyelids were highlighted. With hard contact lenses, the tear film was visualized clearly and changed after a blink when the lens was pulled up by the lid. Conclusions Ultra-high resolution OCT is a potentially promising technique for imaging tears around contact lenses. This successful demonstration of in situ post-lens tear film imaging suggests that OCT could open a new era in studying tear dynamics during contact lens wear. The novel method may lead to new ways of evaluating contact lens fitting. PMID:19265323

  5. Development of a double-stage DDIA apparatus and its application to in-situ melting experiments at high pressures

    NASA Astrophysics Data System (ADS)

    Jing, Z.; Wang, Y.; Tange, Y.; Hilairet, N.; Yu, T.; Sakamaki, T.

    2010-12-01

    Melting experiments at high pressures are critical to our studies on the chemical evolution and dynamics of Earth and other terrestrial planets. A large volume press can generate a homogeneous and stable high-temperature environment, which is the key to melting experiments. However, previous in-situ melting experiments using a large volume press were often restricted to relatively low pressures. In order to expand the P-T conditions, a double-stage 6-8 configuration (6 first-stage anvils and 8 second stage-anvils) has been developed in a DDIA apparatus (DDIA-30), recently installed at the GSECARS Beamline 13-ID-D at the Advanced Photon Source. 27 mm DIA-type first-stage anvils and 14 mm second-stage anvils with the truncation edge length (TEL) of 1.5 mm are employed. A cell assembly that is suitable for synchrotron X-ray studies developed by Tange et al. (2008) has been adopted for melting experiments. High pressure and temperature conditions are generated up to 27 GPa and 2473 K by using tungsten carbide anvils, and up to 35 GPa and 1773 K by using sintered diamond anvils. Both LaCrO3 and TiB2 heater materials have been successfully applied for high-temperature generation. Although TiB2 shows a decrease of resistance at temperatures higher than 2000 K at 20 GPa, we are able to achieve 2473 K with temperature fluctuations in the range of ±30 K. Using tungsten carbide anvils and TiB2 heaters, we have determined the melting curve of gold up to 20 GPa. We constrain the melting temperature based on the disappearance of the gold peaks in energy dispersive X-ray diffraction patterns and the change of sample shape in the radiographic images. The combination of these two observations can reduce the uncertainties in melting temperatures to within 100 K. The measured melting temperatures of gold at 8, 13, and 20 GPa are consistent with the low-pressure results (up to 6 GPa) such as Mirwald and Kennedy (1979). Melting experiments with sintered diamond anvils are currently

  6. Phenomenological in-situ TEM gas exposure studies of palladium particles on MgO at room temperature

    NASA Technical Reports Server (NTRS)

    Heinemann, K.; Poppa, H.; Osaka, T.

    1983-01-01

    It has been found that very small vapor-deposited catalytically active metal particles in the 1-2 nm size range on metal oxide substrates can undergo significant changes when they are exposed to gases such as oxygen or air, or even when allowed to 'anneal' at room temperature (RT) under vacuum conditions. The present investigation is concerned with continued in-situ gas exposures of as-deposited, 1 to 2 nm size palladium particles on MgO to air, oxygen, nitrogen, hydrogen, CO, and water vapor at RT. It is found that the low-pressure exposure to various gases at RT can significantly affect small palladium particles supported on MgO surfaces. Exposure to oxygen for 3 min at 0.0002 m bar produces a considerable amount of coalescence, flattening of the particles, and some distinct crystallographic particle shapes.

  7. Facile production of stable silicon nanoparticles: laser chemistry coupled to in situ stabilization via room temperature hydrosilylation.

    PubMed

    Malumbres, A; Martínez, G; Hueso, J L; Gracia, J; Mallada, R; Ibarra, A; Santamaría, J

    2015-05-14

    Stable, alkyl-terminated, light-emitting silicon nanoparticles have been synthesized in a continuous process by laser pyrolysis of a liquid trialkyl-silane precursor selected as a safer alternative to gas silane (SiH4). Stabilization was achieved by in situ reaction using a liquid collection system instead of the usual solid state filtration. The alkene contained in the collection liquid (1-dodecene) reacted with the newly formed silicon nanoparticles in an unusual room-temperature hydrosilylation process. It was achieved by the presence of fluoride species, also produced during laser pyrolysis from the decomposition of sulfur hexafluoride (SF6) selected as a laser sensitizer. This process directly rendered alkyl-passivated silicon nanoparticles with consistent morphology and size (<3 nm), avoiding the use of costly post-synthetic treatments. PMID:25898392

  8. Comparison of evaporative fluxes from porous surfaces resolved by remotely sensed and in-situ temperature and soil moisture data

    NASA Astrophysics Data System (ADS)

    Wallen, B.; Trautz, A.; Smits, K. M.

    2014-12-01

    The estimation of evaporation has important implications in modeling climate at the regional and global scale, the hydrological cycle and estimating environmental stress on agricultural systems. In field and laboratory studies, remote sensing and in-situ techniques are used to collect thermal and soil moisture data of the soil surface and subsurface which is then used to estimate evaporative fluxes, oftentimes using the sensible heat balance method. Nonetheless, few studies exist that compare the methods due to limited data availability and the complexity of many of the techniques, making it difficult to understand flux estimates. This work compares different methods used to quantify evaporative flux based on remotely sensed and in-situ temperature and soil moisture data. A series of four laboratory experiments were performed under ambient and elevated air temperature conditions with homogeneous and heterogeneous soil configurations in a small two-dimensional soil tank interfaced with a small wind tunnel apparatus. The soil tank and wind tunnel were outfitted with a suite of sensors that measured soil temperature (surface and subsurface), air temperature, soil moisture, and tank weight. Air and soil temperature measurements were obtained using infrared thermography, heat pulse sensors and thermistors. Spatial and temporal thermal data were numerically inverted to obtain the evaporative flux. These values were then compared with rates of mass loss from direct weighing of the samples. Results demonstrate the applicability of different methods under different surface boundary conditions; no one method was deemed most applicable under every condition. Infrared thermography combined with the sensible heat balance method was best able to determine evaporative fluxes under stage 1 conditions while distributed temperature sensing combined with the sensible heat balance method best determined stage 2 evaporation. The approaches that appear most promising for determining the

  9. An in situ high voltage electron microscopy technique for the study of deformation and fracture: In multilayered materials

    SciTech Connect

    Wall, M.A.; Barbee, T.W. Jr.; Weihs, T.P.

    1995-04-14

    A novel, in situ, high voltage electron microscopy technique for the direct observation of the micromechanisms of tensile deformation and fracture in nanostructured materials is detailed. This technique is particularly well suited for the dynamic observations of deformation and fracture in multilayered materials. The success of this type of in situ technique is highly dependent upon unique specimen preparation procedures and sample design, the importance thereof will be discussed. The initial observations discussed here are expected to aid in the understanding of the mechanical behavior of this new class of atomically engineered materials.

  10. Direct 'in situ', low VOC, high yielding, CO2 expanded phase catalytic chain transfer polymerisation: towards scale-up.

    PubMed

    Adlington, Kevin; Green, Anthony; Wang, Wenxin; Howdle, Steven M; Irvine, Derek J

    2013-01-01

    The successful application of catalytic chain transfer polymerisation (CCTP) by adopting an 'in situ' catalyst preparation methodology in several polymerisation media is described. More specifically, this study is focused on reporting the development of 'in situ' CCTP within a CO(2) expanded phase polymerisation process, which achieved high yields of polymer whilst minimising both VOC footprint and CO(2) compression costs. The 'in situ' method is shown to be effective in controlling polymerisations conducted in both conventional solvents and bulk under inert atmosphere, delivering molecular weight reductions and a Cs value of appropriate similar magnitude to those achieved by the benchmark, commercially sourced CoPhBF catalyst. The 'in situ' effect has been achieved with equal efficiency when both using catalysts with different axial ligands and where the complex is required to undergo a facile ligand dissociation in order to create the required catalyst necessary to achieve CCTP control. Furthermore, both catalysts are shown to effectively control polymerisations in a CO(2) expanded phase process, in which a small amount of compressed CO(2) is introduced to reduce the viscosity of the reaction mixture, allowing for easy heat transfer and good catalyst diffusion during reaction. In this way, yield limitations imposed to avoid the Trommsdorff effect required in bulk processing and the need for post precipitation have been successfully overcome. Both of these factors further improve the sustainability of such a polymerisation process. However, the 'in situ', high pressure expanded phase environment was observed to retard the ligand dissociation required for catalyst activation. PMID:23085824

  11. In Situ GISAXS investigation of low-temperature aging in oriented surfactant-mesostructured titania thin films

    DOE PAGESBeta

    Nagpure, Suraj; Das, Saikat; Garlapalli, Ravinder K.; Strzalka, Joseph; Rankin, Stephen E.

    2015-09-11

    In this study, the mechanism of forming orthogonally oriented hexagonal close packed (o-HCP) mesostructures during aging of surfactant-templated titania thin films is elucidated using in situ grazing incidence small-angle x-ray scattering (GISAXS) in a controlled-environment chamber. To promote orthogonal orientation, glass slides are modified with crosslinked Pluronic P123, to provide surfaces chemically neutral towards both blocks of mesophase template P123. At 4 °C and 80% RH, the o-HCP mesophase emerges in thin (~60 nm) films by a direct disorder-to-order transition, with no intermediate ordered mesophase. The Pluronic/titania o-HCP GISAXS intensity emerges only after ~10-12 minutes, much slower than previously reportedmore » for smallmolecule surfactants. The Avrami model applied to the data suggests 2D growth with nucleation at the start of the process with a half-life of 39.7 minutes for the aging time just after the induction period of 7 minutes followed by a period consistent with 1D growth kinetics. Surprisingly, films that are thicker (~250 nm) or cast on unmodified slides form o-HCP mesophase domains, but by a different mechanism (2D growth with continuous nucleation) with faster and less complete orthogonal alignment. Thus, the o-HCP mesophase is favored not only 2 by modifying the substrate, but also by aging at 4 °C, which is below the lower consolute temperature (LCST) of the poly(propylene oxide) block of P123. Consistent with this, in situ GISAXS shows that films aged at room temperature (above the LCST of the PPO block) have randomly oriented HCP mesostructure.« less

  12. Facile production of stable silicon nanoparticles: laser chemistry coupled to in situ stabilization via room temperature hydrosilylation

    NASA Astrophysics Data System (ADS)

    Malumbres, A.; Martínez, G.; Hueso, J. L.; Gracia, J.; Mallada, R.; Ibarra, A.; Santamaría, J.

    2015-04-01

    Stable, alkyl-terminated, light-emitting silicon nanoparticles have been synthesized in a continuous process by laser pyrolysis of a liquid trialkyl-silane precursor selected as a safer alternative to gas silane (SiH4). Stabilization was achieved by in situ reaction using a liquid collection system instead of the usual solid state filtration. The alkene contained in the collection liquid (1-dodecene) reacted with the newly formed silicon nanoparticles in an unusual room-temperature hydrosilylation process. It was achieved by the presence of fluoride species, also produced during laser pyrolysis from the decomposition of sulfur hexafluoride (SF6) selected as a laser sensitizer. This process directly rendered alkyl-passivated silicon nanoparticles with consistent morphology and size (<3 nm), avoiding the use of costly post-synthetic treatments.Stable, alkyl-terminated, light-emitting silicon nanoparticles have been synthesized in a continuous process by laser pyrolysis of a liquid trialkyl-silane precursor selected as a safer alternative to gas silane (SiH4). Stabilization was achieved by in situ reaction using a liquid collection system instead of the usual solid state filtration. The alkene contained in the collection liquid (1-dodecene) reacted with the newly formed silicon nanoparticles in an unusual room-temperature hydrosilylation process. It was achieved by the presence of fluoride species, also produced during laser pyrolysis from the decomposition of sulfur hexafluoride (SF6) selected as a laser sensitizer. This process directly rendered alkyl-passivated silicon nanoparticles with consistent morphology and size (<3 nm), avoiding the use of costly post-synthetic treatments. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01031d

  13. Magic angle spinning nuclear magnetic resonance apparatus and process for high-resolution in situ investigations

    DOEpatents

    Hu, Jian Zhi; Sears, Jr., Jesse A.; Hoyt, David W.; Mehta, Hardeep S.; Peden, Charles H. F.

    2015-11-24

    A continuous-flow (CF) magic angle sample spinning (CF-MAS) NMR rotor and probe are described for investigating reaction dynamics, stable intermediates/transition states, and mechanisms of catalytic reactions in situ. The rotor includes a sample chamber of a flow-through design with a large sample volume that delivers a flow of reactants through a catalyst bed contained within the sample cell allowing in-situ investigations of reactants and products. Flow through the sample chamber improves diffusion of reactants and products through the catalyst. The large volume of the sample chamber enhances sensitivity permitting in situ .sup.13C CF-MAS studies at natural abundance.

  14. Analysis of continuous multi-seasonal in-situ subsurface temperature measurements on Mars

    NASA Astrophysics Data System (ADS)

    Paton, M. D.; Harri, A.-M.; Mäkinen, T.; Savijärvi, H.; Kemppinen, O.; Hagermann, A.

    2015-10-01

    Our investigations reveal the local thermal properties on the Martian surface at the Viking Lander 1 (VL-1) site. We achieved this by using the VL-1 footpad temperature sensor which was buried, and due to its location, was under shadow for extensive periods of time during each sol. Reconstruction of the surface and subsurface temperature history of the regolith in the vicinity of the temperature sensor was made using a 1-D atmospheric column model (UH-FMI) together with a thermal model of the lander. The results have implications for the interpretation of subsurface thermal measurements made close to a spacecraft or rock, interpretation of remote sensing measurements of thermal inertia and understanding the micro-scale behavior of the Martian atmosphere.

  15. Gravity waves in Titan's lower stratosphere from Huygens probe in situ temperature measurements

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Young, Leslie A.; Ferri, Francesca

    2014-01-01

    The Huygens probe recorded atmospheric temperatures during its parachute descent through the atmosphere of Titan. A careful analysis of these data reveals for the first time spectacular but hitherto-unreported small-scale variations in stratospheric temperatures that we interpret as gravity waves, consistent with detection of such waves at higher altitudes by other means. The structures have a vertical wavelength of 3-8 km and a peak-peak amplitude of ˜2 K that is roughly constant over altitudes from ˜140 km, where measurements began, to ˜60 km. This altitude, below which no significant temperature waves are seen, coincides with a local maximum in the zonal wind profile, and is close to where the Brunt-Väisälä frequency is highest. It seems possible that the zonal wind field influences the vertical gravity wave propagation.

  16. In-situ monitoring of internal local temperature and voltage of proton exchange membrane fuel cells.

    PubMed

    Lee, Chi-Yuan; Fan, Wei-Yuan; Hsieh, Wei-Jung

    2010-01-01

    The distribution of temperature and voltage of a fuel cell are key factors that influence performance. Conventional sensors are normally large, and are also useful only for making external measurements of fuel cells. Centimeter-scale sensors for making invasive measurements are frequently unable to accurately measure the interior changes of a fuel cell. This work focuses mainly on fabricating flexible multi-functional microsensors (for temperature and voltage) to measure variations in the local temperature and voltage of proton exchange membrane fuel cells (PEMFC) that are based on micro-electro-mechanical systems (MEMS). The power density at 0.5 V without a sensor is 450 mW/cm(2), and that with a sensor is 426 mW/cm(2). Since the reaction area of a fuel cell with a sensor is approximately 12% smaller than that without a sensor, but the performance of the former is only 5% worse. PMID:22163556

  17. Aerosol-Cloud Interaction Determined by Both in Situ and Satellite Data Over a Northern High-Latitude Site

    NASA Technical Reports Server (NTRS)

    Lihavainen, H.; Kerminen, V.-M.; Remer, L. A.

    2009-01-01

    The first aerosol indirect effect over a clean, northern high-latitude site was investigated by determining the aerosol cloud interaction (ACI) using three different approaches; ground-based in situ measurements, combined ground-based in situ measurements 5 and satellite retrievals and using only satellite retrievals. The obtained values of ACI were highest for in situ ground-based data, clearly lower for combined ground-based and satellite data, and lowest for data relying solely on satellite retrievals. One of the key findings of this study was the high sensitivity of ACI to the definition of the aerosol burden. We showed that at least a part of the variability in ACI can be explained by 10 how different investigators have related dierent cloud properties to "aerosol burden".

  18. An in situ neutron diffraction measurement of the pressure-temperature evolution of a MgD2:TiD2 mixture

    NASA Astrophysics Data System (ADS)

    Moser, D.; Bull, D. J.; Cowpe, J. S.; Roach, D. L.; Ross, D. K.; Noréus, D.; Tucker, M. G.

    2010-12-01

    The hydrogen storage capacity of Mg-Ti-H films is approximately five times that of conventional metal hydride electrodes in NiMH-batteries. Mg and Ti are considered to be immiscible in the bulk and the ambient pressure phase diagram of Mg and Ti indicates that no binary stable bulk compounds are formed. However, in the presence of hydrogen, an Mg-Ti-H phase has been obtained by Kyoi et al. using a high pressure synthesis - where magnesium hydride is compacted with different TM-hydrides in an anvil cell at pressures of the order several GPa (4-8 GPa) and at a temperature of 873 K. In this work, we have proved the feasibility of in situ powder diffraction using the Paris-Edinburgh high pressure cell for the observation of structural changes on this system and we propose modifications to improve the output of the experiment.

  19. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  20. HIGH TEMPERATURE THERMOCOUPLE

    DOEpatents

    Eshayu, A.M.

    1963-02-12

    This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact. The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream. (AEC)

  1. High temperature thermometric phosphors

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  2. High temperature thermometric phosphors

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub x},Eu{sub y} wherein: 0.1 wt % {<=} x {<=} 20 wt % and 0.1 wt % {<=} y {<=} 20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  3. High temperature electrochemical scanning tunneling microscope instrument

    NASA Astrophysics Data System (ADS)

    Shkurankov, Andrei; Endres, Frank; Freyland, Werner

    2002-01-01

    We present a novel construction of a scanning tunneling microscope (STM) for investigations of fluid/solid interfaces and, in particular, for in situ electrochemical measurements at elevated temperatures. A special feature of this instrument is a vacuum tight connection of the electrochemical cell with the STM scanner via a flexible metal bellow. This enables measurements with highly reactive and volatile fluids at high temperatures. Details of the mechanical and electronic parts of this setup are described. Test measurements on the electrodeposition of metals from molten salt electrolytes have been performed. The Ag deposition has been studied in an acidic room temperature molten salt composed of 1-butyl-3-methyl-imidazoliumchloride and AlCl3 up to 355 K. As a second example the Al deposition from molten AlCl3-NaCl has been tested up to 500 K. First results of these experiments are briefly presented.

  4. Toward Biocompatible Nuclear Hyperpolarization Using Signal Amplification by Reversible Exchange: Quantitative in Situ Spectroscopy and High-Field Imaging

    PubMed Central

    2014-01-01

    Signal amplification by reversible exchange (SABRE) of a substrate and parahydrogen at a catalytic center promises to overcome the inherent insensitivity of magnetic resonance. In order to apply the new approach to biomedical applications, there is a need to develop experimental equipment, in situ quantification methods, and a biocompatible solvent. We present results detailing a low-field SABRE polarizer which provides well-controlled experimental conditions, defined spins manipulations, and which allows in situ detection of thermally polarized and hyperpolarized samples. We introduce a method for absolute quantification of hyperpolarization yield in situ by means of a thermally polarized reference. A maximum signal-to-noise ratio of ∼103 for 148 μmol of substance, a signal enhancement of 106 with respect to polarization transfer field of SABRE, or an absolute 1H-polarization level of ≈10–2 is achieved. In an important step toward biomedical application, we demonstrate 1H in situ NMR as well as 1H and 13C high-field MRI using hyperpolarized pyridine (d3) and 13C nicotinamide in pure and 11% ethanol in aqueous solution. Further increase of hyperpolarization yield, implications of in situ detection, and in vivo application are discussed. PMID:24397559

  5. High-temperature electronics

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1987-11-01

    In recent years, there was a growing need for electronics capable of sustained high-temperature operation for aerospace propulsion system instrumentation, control and condition monitoring, and integrated sensors. The desired operating temperature in some applications exceeds 600 C, which is well beyond the capability of currently available semiconductor devices. Silicon carbide displays a number of properties which make it very attractive as a semiconductor material, one of which is the ability to retain its electronic integrity at temperatures well above 600 C. An IR-100 award was presented to NASA Lewis in 1983 for developing a chemical vapor deposition process to grow single crystals of this material on standard silicon wafers. Silicon carbide devices were demonstrated above 400 C, but much work remains in the areas of crystal growth, characterization, and device fabrication before the full potential of silicon carbide can be realized. The presentation will conclude with current and future high-temperature electronics program plans. Although the development of silicon carbide falls into the category of high-risk research, the future looks promising, and the potential payoffs are tremendous.

  6. Low Temperature Engineering Applied to Lunar in-situ Resource Utilization

    NASA Astrophysics Data System (ADS)

    Zhang, Burt. X.; Chui, Talso. C.

    2006-04-01

    In support of NASA's Exploration Mission low-temperature scientists and engineers have investigated the process of extracting volatile materials from the lunar regolith, their purification/liquefaction, and storage. Volatiles such as O2, N2, He and water can be used to support human habitation, while H2 and O2 can be used as rocket fuel. Using a sorption pump, passive thermal radiators, temperature control, and a small number of storage vessels and valves, a purification and storage system can be designed to operate inside a permanently shadowed polar crater where volatiles are expected to be most abundant. The basic approach can be used as the basis for a small experiment on a prospecting mission, which will serve as a proof of concept for a much bigger cryogenic fluids facility to support NASA's human exploration effort. A similar design with sufficient radiation shielding can be operated on the Moon's surface.

  7. In-situ coal seam and overburden permeability characterization combining downhole flow meter and temperature logs.

    NASA Astrophysics Data System (ADS)

    Busse, Julia; Scheuermann, Alexander; Bringemeier, Detlef; Hossack, Alex; Li, Ling

    2016-06-01

    The planning and design of any coal mine development requires among others a thorough investigation of the geological, geotechnical and hydrogeological subsurface conditions. As part of a coal mine exploration program we conducted heat pulse vertical flow meter testing. The flow data were combined with absolute and differential temperature logging data to gain information about the hydraulic characteristics of two different coal seams and their over- and interburden. For the strata that were localised based on geophysical logging data including density, gamma ray and resistivity hydraulic properties were quantified. We demonstrate that the temperature log response complements the flow meter log response. A coupling of both methods is therefore recommended to get an insight into the hydraulic conditions in a coal seam and its overburden.

  8. Highly indistinguishable photons from deterministic quantum-dot microlenses utilizing three-dimensional in situ electron-beam lithography

    PubMed Central

    Gschrey, M.; Thoma, A.; Schnauber, P.; Seifried, M.; Schmidt, R.; Wohlfeil, B.; Krüger, L.; Schulze, J. -H.; Heindel, T.; Burger, S.; Schmidt, F.; Strittmatter, A.; Rodt, S.; Reitzenstein, S.

    2015-01-01

    The success of advanced quantum communication relies crucially on non-classical light sources emitting single indistinguishable photons at high flux rates and purity. We report on deterministically fabricated microlenses with single quantum dots inside which fulfil these requirements in a flexible and robust quantum device approach. In our concept we combine cathodoluminescence spectroscopy with advanced in situ three-dimensional electron-beam lithography at cryogenic temperatures to pattern monolithic microlenses precisely aligned to pre-selected single quantum dots above a distributed Bragg reflector. We demonstrate that the resulting deterministic quantum-dot microlenses enhance the photon-extraction efficiency to (23±3)%. Furthermore we prove that such microlenses assure close to pure emission of triggered single photons with a high degree of photon indistinguishability up to (80±7)% at saturation. As a unique feature, both single-photon purity and photon indistinguishability are preserved at high excitation power and pulsed excitation, even above saturation of the quantum emitter. PMID:26179766

  9. Highly indistinguishable photons from deterministic quantum-dot microlenses utilizing three-dimensional in situ electron-beam lithography.

    PubMed

    Gschrey, M; Thoma, A; Schnauber, P; Seifried, M; Schmidt, R; Wohlfeil, B; Krüger, L; Schulze, J-H; Heindel, T; Burger, S; Schmidt, F; Strittmatter, A; Rodt, S; Reitzenstein, S

    2015-01-01

    The success of advanced quantum communication relies crucially on non-classical light sources emitting single indistinguishable photons at high flux rates and purity. We report on deterministically fabricated microlenses with single quantum dots inside which fulfil these requirements in a flexible and robust quantum device approach. In our concept we combine cathodoluminescence spectroscopy with advanced in situ three-dimensional electron-beam lithography at cryogenic temperatures to pattern monolithic microlenses precisely aligned to pre-selected single quantum dots above a distributed Bragg reflector. We demonstrate that the resulting deterministic quantum-dot microlenses enhance the photon-extraction efficiency to (23±3)%. Furthermore we prove that such microlenses assure close to pure emission of triggered single photons with a high degree of photon indistinguishability up to (80±7)% at saturation. As a unique feature, both single-photon purity and photon indistinguishability are preserved at high excitation power and pulsed excitation, even above saturation of the quantum emitter. PMID:26179766

  10. Novel Integration Approach for In situ Monitoring of Temperature in Micro-direct Methanol Fuel Cell

    NASA Astrophysics Data System (ADS)

    Lee, Chi-Yuan; Huang, Ren-De; Chuang, Chih-Wei

    2007-10-01

    In this work, a porous silicon layer is fabricated as the gas diffusion layer (GDL) of a micro-direct methanol fuel cell (μDMFC) using micro-electro-mechanical-systems (MEMS) technology. Platinum is deposited on surface of the porous silicon layer to improve the electrical conductivity of the μDMFC. Physical vapor deposition (PVD) was utilized to deposit Pt metal and wet etching was adopted to form the conductive layer and micro-thermal sensors. The Pt acted both as a current collector and a micro-thermal sensor. We fabricated a resistance temperature detector (RTD) sensor for integration with the gas diffusion layer on the bipolar plate to measure the temperature inside the μDMFC. GDLs with pores of various sizes (10, 30, and 50 μm) were considered to test the performance of the μDMFC. A silicon wafer (500 μm) was etched using KOH wet etching to yield fuel channels with a depth of 450 μm and a width of 200 μm. Then, a porous silicon layer was formed by deep reactive ion etching (DRIE) to act as the GDL of the μDMFC. The experimental results obtained at various fuel flow rates, pore sizes and other operating conditions demonstrate that the maximum power density of the μDMFC is 1.784 mW/cm2, which was reached at 203 mV with 50-μm-diameter holes. The microsensor temperature was determined to be in the range from 20 to 46 °C and the resistance of the microsensor was in the range from 7.524 to 7.677 kΩ. Experimental results demonstrate that temperature is almost linearly related to resistance and that accuracy and sensitivity are 0.3 °C and 7.82× 10-4/°C, respectively.

  11. In situ synthesized novel biocompatible titania-chitosan nanocomposites with high surface area and antibacterial activity.

    PubMed

    Kavitha, K; Sutha, S; Prabhu, M; Rajendran, V; Jayakumar, T

    2013-04-01

    A series of titania-chitosan nanocomposites (2:x (0.12, 0.25, 0.5, 1.0 and 2.0g)) were synthesized using in situ sol-gel method and comprehensively characterized using conventional techniques. The resultant particles showed anatase phase, spherical and irregular morphology with particle size of 4.5-10.5nm. Nanocomposites with higher surface area (114-265m(2)/g) and high purity were obtained. The characterized samples were analyzed in 1.5mM simulated body fluid (1.5 SBF) and human gastric adenocarcinoma cell line to explore the bioactivity and biocompatibility. Antibacterial activity against Staphylococcus aureus was also evaluated. The formation of apatite layer on 1.5 SBF-immersed samples confirms the bioactivity of all the nanocomposites. High surface area, appropriate hydroxyapatite formation, specific antibacterial action, increased cell viability, controlled swelling and degrading rate are favorably achieved at 2:1 nanocomposite ratio. This study shows titania-chitosan nanocomposites as the promising biomaterial for orthopedic and tissue engineering applications. PMID:23499117

  12. High lactose tolerance in North Europeans: a result of migration, not in situ milk consumption.

    PubMed

    Vuorisalo, Timo; Arjamaa, Olli; Vasemägi, Anti; Taavitsainen, Jussi-Pekka; Tourunen, Auli; Saloniemi, Irma

    2012-01-01

    The main carbohydrate in milk is lactose, which must be hydrolyzed to glucose and galactose before the sugars can be digested. While 65% or more of the total human population are lactose intolerant, in some human populations lactase activity commonly persists into adulthood. Lactose tolerance is exceptionally widespread in Northern European countries such as Sweden and Finland, with tolerance levels of 74% and 82%, respectively. Theoretically, this may result either from a strong local selection pressure for lactose tolerance, or from immigration of lactose tolerant people to Northern Europe. We provide several lines of archaeological and historical evidence suggesting that the high lactose tolerance in North Europeans cannot be explained by selection from in situ milk consumption. First, fresh cow milk has not belonged to the traditional diet of Swedes or Finns until recent times. Second, not enough milk has been available for adult consumption. Cattle herding has been neither widespread nor productive enough in Northern Europe to have provided constant access to fresh milk. We suggest that the high prevalence of lactose tolerance in Finland in particular may be explained by immigration of people representing so-called Corded Ware Culture, an early culture representing agricultural development in Europe. PMID:22643754

  13. In situ inspection of inclusions in toughened glass panels of high-rise buildings

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Fang, Zhong Ping; Reading, Ivan; Zhao, Liping; Chow, Siew Loong

    2005-04-01

    Transparent toughened glass panels are widely installed in high-rise buildings. There is a growing need for inspection to detect the presence of detrimental inclusions of Nickel Sulfide. These inclusions can cause toughened glass to shatter, possibly causing property damage or injury. Optical equipment has been developed which can detect the inclusions in-situ. Light is coupled into a glass panel and propagates along the glass by total internal reflection. An inclusion in the glass will cause the light to scatter. Once an inclusion is found, it will be observed at higher magnification and the detailed image will be processed. By the analysis of its key features, the inclusion type can be identified. The coupling medium is made of a transparent, soft and deformable material. The equipment can be attached to a glass panel by vacuum suction. The optical system can scan the whole glass panel with a constant force spring as anti-weight structure. The whole system is fast, convenient and highly effective. A patent has been filed for this apparatus.

  14. A Software App for Radiotherapy with In-situ Dose-painting using high Z nanoparticles

    PubMed Central

    Jermoumi, M; Yucel, A; Hao, Y; Cifter, G; Sajo, E; Ngwa, W

    2016-01-01

    The purpose of this work is to develop an user friendly and free-to-download application software that can be employed for modeling Radiotherapy with In-situ Dose-painting (RAID) using high-Z nanoparticles (HZNPs). The RAID APP is software program written in Matlab (Mathworks, Natick, MA, USA) based on deterministic code developed to simulate the space-time intra-tumor HZNPs biodistribution within the tumor, and the corresponding dose enhancement in response to low dose rate (LDR) brachytherapy of I-125, Pd-102, Cs-131 and kilovoltage x-rays such as 50 keV and 100 keV. Through the GUI of RAID APP, the user will be directed to different features to compute various parameters related to the dose enhancement and the biodistribution of NPs within high risk tumor sub-volumes. The software was developed as tool for research purposes with potential for subsequent development to guide dose-painting treatment planning using radiosensitizers such as gold (Au) and platinum (Pt).

  15. Transformation of Mo and W thiosalts into unsupported sulfide catalysts: A temperature dependent in-situ spectroscopic investigation

    SciTech Connect

    Yi, Yanjiao; Williams, Christopher T.; Glascock, Mary; Xiong, Guang; Lauterbach, Jochen; Liang, Changhai

    2014-08-15

    Highlights: • TPD–MS results suggest that the majority of S remains in the solid sample after decomposition. • Decomposition of the (CH{sub 3}){sub 4}N is not directly correlated with that of the MS{sub 4}{sup 2−} species. • Surface of materials does not track directly with the bulk at various treatment temperatures. • ATT-derived materials retained a significant amount of +6 state consistent with the precursor. - Abstract: The thermal decomposition of ammonium thiomolybdate (ATM), ammonium thiotungstate (ATT), tetramethylammonium thiomolybdate (TMATM) and tetramethylammonium thiotungstate (TMATT) are investigated as a function of temperature by using thermogravimetric analysis (TGA), temperature-programmed decomposition with mass spectroscopy (TPS–MS), in-situ Fourier transform infrared (FTIR) and Raman spectroscopies, and X-ray photoelectron spectroscopy (XPS). The results allow for correlations to be made between the changes in the bulk and surface structures of the materials, and the evolution of gas-phase decomposition products. The major difference between the ammonium and tetramethylammonium precursors is the complexity of the thermal decomposition profile, which is found to follow two steps over a wide temperature range for the former, but one step over a relatively narrow range for the latter materials. Raman and FTIR spectra reveal the decomposition of the ammonium and tetramethylammonium groups, along with the decomposition of the initial sulfide structures to metal disulfides. For both sets of precursors, XPS results show that the surface of the resulting materials at various temperatures of treatment does not track directly with the state of the bulk material. While the ATM, TMATM, and TMATT-derived material surfaces are reduced to the 4{sup +} state at the highest temperature, indicating disulfides, the ATT-derived materials still retained a significant amount of W{sup 6+} state consistent with the starting precursor.

  16. Tensile deformation behaviors of Zircaloy-4 alloy at ambient and elevated temperatures: In situ neutron diffraction and simulation study

    NASA Astrophysics Data System (ADS)

    Li, Hongjia; Sun, Guangai; Woo, Wanchuck; Gong, Jian; Chen, Bo; Wang, Yandong; Fu, Yong Qing; Huang, Chaoqiang; Xie, Lei; Peng, Shuming

    2014-03-01

    Tensile stress-strain relationship of a rolled Zircaloy-4 (Zr-4) plate was examined in situ using a neutron diffraction method at room temperature (RT, 25 °C) and an elevated temperature (250 °C). Variations of lattice strains were obtained as a function of macroscopic bulk strains along prismatic (101¯0), basal (0 0 0 2) and pyramidal (101¯1) planes in the hexagonal close-packed structure of the Zr-4. The mechanisms of strain responses in these three major planes were simulated using elastic-plastic self-consistent (EPSC) model based on Hill-Hutchinson method, thus the inter-granular stresses and deformation systems of each individual grain under loading were obtained. Results show that there is a good agreement between the EPSC modeling and neutron diffraction measurements in terms of macroscopic stress-strain relationship and lattice strain evolutions of the planes at RT. However, there is a slight discrepancy in the lattice strains obtained from the EPSC modeling and neutron diffraction when the specimen was deformed at 250 °C. Analysis of grain structure and texture obtained using electron back-scattered diffraction suggests that dynamic recovery process is significant during the tensile deformation at the elevated temperature, which was not considered in the simulation.

  17. Laboratory evaluation of the Level TROLL 100 manufactured by In-Situ Inc.: results of pressure and temperature tests

    USGS Publications Warehouse

    Carnley, Mark V.; Fulford, Janice M.; Brooks, Myron H.

    2013-01-01

    The Level TROLL 100 manufactured by In-Situ Inc. was evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility (HIF) for conformance to the manufacturer’s accuracy specifications for measuring pressure throughout the device’s operating temperature range. The Level TROLL 100 is a submersible, sealed, water-level sensing device with an operating pressure range equivalent to 0 to 30 feet of water over a temperature range of −20 to 50 degrees Celsius (°C). The device met the manufacturer’s stated accuracy specifications for pressure within its temperature-compensated operating range of 0 to 50 °C. The device’s accuracy specifications did not meet established USGS requirements for primary water-stage sensors used in the operation of streamgages, but the Level TROLL 100 may be suitable for other hydrologic data-collection applications. As a note, the Level TROLL 100 is not designed to meet USGS accuracy requirements. Manufacturer accuracy specifications were evaluated, and the procedures followed and the results obtained are described in this report. USGS accuracy requirements are routinely examined and reported when instruments are evaluated at the HIF.

  18. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-01-24

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with superheated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200 °C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220 °C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: 1. At relative pressures over 0.6 the capillarity forces are very important. 2. There is no significant temperature effect. 3. Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. 4. Pores smaller than 15 Å do not contribute to the adsorbed mass.

  19. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-12-31

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with super-heated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200{degrees}C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220{degrees}C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: (1) At relative pressures over 0.6 the capillarity forces are very important. (2) There is no significant temperature effect. (3) Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. (4) Pores smaller than 15 {Angstrom} do not contribute to the adsorbed mass.

  20. High-order harmonic generation in a plasma plume of in situ laser-produced silver nanoparticles

    SciTech Connect

    Singhal, H.; Naik, P. A.; Chakera, J. A.; Chakravarty, U.; Vora, H. S.; Srivastava, A. K.; Mukherjee, C.; Navathe, C. P.; Deb, S. K.; Gupta, P. D.; Ganeev, R. A.

    2010-10-15

    The results of the experimental study of high-order harmonic generation (HHG) from the interaction of 45-fs Ti:sapphire laser pulses with plasma plumes of Ag nanoparticles produced in situ are presented in this article. The nanoparticles were generated by the interaction of 300-ps, 20-mJ laser pulses with bulk silver targets at an intensity of {approx}1x10{sup 13} W/cm{sup 2}. The spectral characteristics of the HHG from nanoparticles produced in situ are compared with the HHG from monoparticle plasma plumes and with the HHG from preformed nanoparticle-containing plasma plumes. The cutoff harmonic order generated using the in situ silver nanoparticles is at the 21st harmonic order.

  1. High throughput and multiplex localization of proteins and cells for in situ micropatterning using pneumatic microfluidics.

    PubMed

    Wang, Jian-Chun; Liu, Wenming; Tu, Qin; Ma, Chao; Zhao, Lei; Wang, Yaolei; Ouyang, Jia; Pang, Long; Wang, Jinyi

    2015-02-01

    Micropatterning technologies are emerging as an enabling tool for various microfluidic-based applications in life sciences. However, the high throughput and multiplex localization of multiple bio-components in a microfluidic device has not yet been well established. In this paper, we describe a simple and in situ micropatterning method using an integrated microfluidic device with pneumatic microstructures (PμSs) for highly controllable immobilization of both proteins and cells in a high throughput, geometry-dynamic, and multi-patterning way. The precise Pluronic F127 passivation of a microchamber surface except the PμS-blocked regions was performed and characterized, and the spatial dynamics and consistency of both the PμSs and protein/cell micropatterning were optically evaluated and quantitatively demonstrated too. Furthermore, a systematic investigation of PμS-assisted micropatterning in microfluidics was carried out. The feature of high throughput and spatial control of micropatterning can be simply realized by using the well-designed PμS arrays. Meanwhile, the co-micropatterning of different proteins (bovine serum albumin and chicken egg albumin) and cells (human umbilical vein endothelial cells and human hepatocellular carcinoma cells) in a microfluidic device was successfully accomplished with the orderly serial manipulation of PμS groups. We demonstrate that PμS-assisted micropatterning can be applied as a convenient microfluidic component for large-scale and diversified protein/cell patterning and manipulation, which could be useful for cell-based tissue organization, high-throughput imaging, protein-related interactions and immunoassays. PMID:25453039

  2. In situ high pressure infrared study of the carbon environment in (Mg,Fe)CO3 carbonate

    NASA Astrophysics Data System (ADS)

    Boulard, E.; Pan, D.; Galli, G.; Mao, W. L.

    2013-12-01

    Carbonates are likely to be the main carbon-bearing phase in the Earth's mantle, and therefore knowledge of their mineral physics down to core mantle boundary conditions is critical for understanding the deep carbon cycle. (Mg,Fe)CO3 has been the focus of many recent high pressure studies which indicate several crystallographic changes. An electronic spin transition in the iron end-member has been reported at approximately 45 GPa. As a result, a change in the volume and the equation of state, and moreover a change in the rate of C-O bond distortion were described by X-ray diffraction (XRD) studies (B. Lavina et al., 2009; 2010). At higher pressures, above 80 GPa, we have observed the transformation of (Mg,Fe)CO3 carbonate into a new high-pressure high-temperature phase by in situ XRD (Boulard et al., 2011). Investigation of the carbon environment had previously been limited to ex situ studies at ambient conditions after releasing the pressure on the sample. Spectroscopy on the carbon C-k edge indicated a potential change in the carbon environment, and a transformation of the carbonate trigonal CO3 groups into CO4 tetrahedra had been proposed (Boulard et al., 2011). However this interpretation is still under debate. To follow the evolution of C-O bonds and clarify the existence of CO4 tetrahedra in high-pressure carbonate phases, we combined in-situ infrared spectroscopy with theoretical calculations. Mid-infrared spectroscopy, performed at high pressure before and after laser heating at U2A, NSLS, BNL show several changes in the (Mg,Fe)CO3 spectrum after laser heating at 103 GPa. We will discuss the interpretation of these new spectroscopic signatures and the possibility of a dramatic change in the carbon environment. References: Boulard, E. et al., (2011). New host for carbon in the deep Earth. PNAS, 108(13), 5184-5187. Lavina, B. et al., (2009). Siderite at lower mantle conditions and the effects of the pressure-induced spin-pairing transition. Geophysical