Sample records for high-pressure viscosity behavior

  1. Research on viscosity of metal at high pressure (United States)

    Li, Y.; Liu, F.; Ma, X.; Zhang, M.


    A new experimental technique, the flyer-impact method, is proposed in this article to investigate the viscosity coefficient of shocked metals. In this technique, a shock wave with a sinusoidal perturbation on the front is induced by the sinusoidal profile of the impact surface of the sample by use of a two-stage light-gas gun, and the oscillatory damping process of the perturbation amplitude is monitored by electric pins. The damping processes of aluminum at 78 and 101 GPa and iron at 159 and 103 GPa are obtained by this technique, which supplement the existing data by measuring the viscosity coefficient via a dynamic high-pressure method. Applying the formula of Miller and Ahrens to fit the experimental data, the shear viscosity coefficients of aluminum at 78 and 101 GPa are 1350 ± 500 and 1200 ± 500 Pa s, respectively, and those of iron at 159 and 103 GPa are 1150 ± 1000 and 4800 ± 1000 Pa s, respectively. The values measured by the flyer-impact method, approximately 103 Pa s, are consistent with those measured by Sakharov's method, while still greatly differing from those measured by static high-pressure methods. In dynamic high-pressure experiments, the shear viscosity is related to dislocation motion in the solid material, while that in static high-pressure experiments is related to the diffusion motion of atoms or molecules in liquids. Therefore, there are different physical meanings of shear viscosity in dynamic and static high-pressure experiments, and there is no comparability among these results.

  2. In situ viscosity measurements of albite melt under high pressure

    CERN Document Server

    Funakoshi, K I; Terasaki, H


    The viscosities of albite (NaAlSi sub 3 O sub 8) melt under high pressures have been measured using an x-ray radiography falling sphere method with synchrotron radiation. This method has enabled us to determine the precise sinking velocity directly. Recent experiments of albite melt showed the presence of a viscosity minimum around 5 GPa (Poe et al 1997 Science 276 1245, Mori et al 2000 Earth Planet. Sci. Lett. 175 87). We present the results for albite melt up to 5.2 GPa at 1600 and 1700 deg. C. The viscosity minimum is clearly observed to be around 4.5 GPa, and it might be explained not by the change of the compression mechanism in albite melt but by change of the phase itself.

  3. High-pressure viscosity behavior of x 1,1,1,2-tetrafluoroethane (HFC-134a)+(1-x) triethylene glycol dimethylether (TriEGDME) mixtures: Measurements and modeling

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Baylaucq, A.; Cisneros, Sergio


    In this work new dynamic viscosity measurements for binary mixtures containing a refrigerant (HFC-134a, CF3CH2F) and a lubricant (TriEGDME, CH3O(CH2OCH2)(3)CH3) are reported. The measurements were carried out at temperatures between 293.15 and 373.15 K and pressures from 10 to 100 MPa, for two mole...... for this binary system have been used to test the ability of several viscosity models having different origins and theoretical backgrounds. The considered models range from simple mixing rules, through empirical correlations, such as the self-referencing model and the LBC model, to recent approaches...

  4. Experimental viscosity measurements of biodiesels at high pressure

    Directory of Open Access Journals (Sweden)

    Schaschke C.J.


    Full Text Available The viscosity of biodiesels of soybean and rapeseed biodiesels blended with mineral diesel fuel were measured at pressures of up to 200 MPa. Using a falling sinker-type viscometer reproducible viscosity data were obtained based on the time taken for a sinker to descend a fixed distance down an enclosed tube under the influence of gravity. Measurements were taken using pressures which correspond to those of interest in automotive common rail diesel engines, and at temperatures of between 25ºC and 80ºC. In all cases, the viscosity of the biodiesel blends were found to increase exponentially for which the blends were noted as being more viscous than pure mineral fuels. A pressure-freezing effect was not observed for the blends.

  5. High-pressure viscosity measurements for the ethanol plus toluene binary system

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Baylaucq, A.; Watson, G.


    The viscosity of the ethanol + toluene binary system has been measured with a falling-body viscometer for seven compositions as well as for the pure ethanol in the temperature range from 293.15 to 353.15 K and up to 100 MPa with an experimental uncertainty of 2%. At 0.1 MPa the viscosity has been...... measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of 1%. A total of 209 experimental measurements have been obtained for this binary system, which reveals a non-monotonic behavior of the viscosity as a function of the composition, with a minimum. The viscosity behavior...... interacting system showing a negative deviation from ideality. The viscosity of this binary system is represented by the Grunberg-Nissan and the Katti-Chaudhri mixing laws with an overall uncertainty of 12% and 8%, respectively. The viscosity of methanol (23 point) has also been measured in order to verify...

  6. Experimental and Theoretical Investigations on Viscosity of Fe-Ni-C Liquids at High Pressures (United States)

    Chen, B.; Lai, X.; Wang, J.; Zhu, F.; Liu, J.; Kono, Y.


    Understanding and modeling of Earth's core processes such as geodynamo and heat flow via convection in liquid outer cores hinges on the viscosity of candidate liquid iron alloys under core conditions. Viscosity estimates from various methods of the metallic liquid of the outer core, however, span up to 12 orders of magnitude. Due to experimental challenges, viscosity measurements of iron liquids alloyed with lighter elements are scarce and conducted at conditions far below those expected for the outer core. In this study, we adopt a synergistic approach by integrating experiments at experimentally-achievable conditions with computations up to core conditions. We performed viscosity measurements based on the modified Stokes' floating sphere viscometry method for the Fe-Ni-C liquids at high pressures in a Paris-Edinburgh press at Sector 16 of the Advanced Photon Source, Argonne National Laboratory. Our results show that the addition of 3-5 wt.% carbon to iron-nickel liquids has negligible effect on its viscosity at pressures lower than 5 GPa. The viscosity of the Fe-Ni-C liquids, however, becomes notably higher and increases by a factor of 3 at 5-8 GPa. Similarly, our first-principles molecular dynamics calculations up to Earth's core pressures show a viscosity change in Fe-Ni-C liquids at 5 GPa. The significant change in the viscosity is likely due to a liquid structural transition of the Fe-Ni-C liquids as revealed by our X-ray diffraction measurements and first-principles molecular dynamics calculations. The observed correlation between structure and physical properties of liquids permit stringent benchmark test of the computational liquid models and contribute to a more comprehensive understanding of liquid properties under high pressures. The interplay between experiments and first-principles based modeling is shown to be a practical and effective methodology for studying liquid properties under outer core conditions that are difficult to reach with the current

  7. Viscosity of Liquid Fe-17wt% Si at High Pressure and Temperature (United States)

    Yu, X.; Secco, R. A.; Wang, Y.; Ohtani, E.; Terasaki, H.; Suzuki, A.


    In situ X-ray radiography falling-sphere experiments on liquid Fe-17wt% Si viscosity were carried out from 2 GPa to 7 GPa at APS and Spring-8 in multi-anvil apparati. Video images were recorded at speeds of up to 62 frames/sec. Both Re spheres coated with alumina and composite spheres of Pt or Re core and a mechanically prepared ruby mantle were used in the high pressure melts to avoid chemical reaction between the sample and the probing metallic spheres. The viscosity at the melting temperature was calculated from activation energy, which was determined from a combination of theoretical and experimental values of viscosity at ambient pressure. At the early stages of the compression (up to ~ 5.4 GPa), the viscosity increases but later appears to approach a constant value of 69 mPa.s in the higher pressure range. The constant relating activation energy to melting temperature, g, is 6.8 from this study. Assuming that temperature varies adiabatically in the core and melting temperature Tm at the inner core boundary is 4766 K and dTm dP = 10 K/GPa, the viscosity at the core-mantle boundary, inferred from this study, decreases to a value very close to the ambient pressure viscosity of 6 mPa.s for liquid metal.

  8. The high-pressure behavior of bloedite

    DEFF Research Database (Denmark)

    Comodi, Paola; Nazzareni, Sabrina; Balic Zunic, Tonci


    High-pressure single-crystal synchrotron X‑ray diffraction was carried out on a single crystal of bloedite [Na2Mg(SO4)24H2O] compressed in a diamond-anvil cell. The volume-pressure data, collected up to 11.2 GPa, were fitted by a second- and a third-order Birch-Murnaghan equation of state (EOS), ...

  9. Experiment on wear behavior of high pressure gas seal faces (United States)

    Xu, Jing; Peng, Xudong; Bai, Shaoxian; Meng, Xiangkai; Li, Jiyun


    Current researches show that mechanical deformation of seal ring face makes fluid film clearance decrease at high pressure side, thus a divergent clearance is formed and face wear occurs more seriously at the high pressure side than that on the low pressure side. However, there is still lack of published experimental works enough to prove the theoretical results. In this paper, a spiral groove dry gas seal at high pressures is experimentally investigated so as to prove the face wear happened at the high pressure side of seal faces due to the face mechanical deformation, and the wear behavior affected by seal ring structure is also studied. The experimental results show that face wear would occur at the high pressure side of seal faces due to the deformation, thus the leakage and face temperature increase, which all satisfies the theoretical predictions. When sealed pressure is not less than 5 MPa, the pressure can provide enough opening force to separate the seal faces. The seal ring sizes have obvious influence on face wear. Face wear, leakage and face temperature of a dry gas seal with the smaller cross sectional area of seal ring are less than that of a dry gas seal with bigger one, and the difference of leakage rate between these two sizes of seal face width is in the range of 24%-25%. Compared with the effect of seal ring sizes, the effect of secondary O-ring seal position on face deformation and face wear is less. The differences between these two types of dry gas seals with different secondary O-ring seal positions are less than 5.9% when the rotational speed varies from 0 to 600 r/min. By linking face wear and sealing performance changes to the shift in mechanical deformation of seal ring, this research presents an important experimental method to study face deformation of a dry gas seal at high pressures.

  10. High-pressure behavior of CaMo O4 (United States)

    Panchal, V.; Garg, N.; Poswal, H. K.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.; Cavalli, E.


    We report a high-pressure study of tetragonal scheelite-type CaMo O4 up to 29 GPa. In order to characterize its high-pressure behavior, we have combined Raman and optical-absorption measurements with density functional theory calculations. We have found evidence of a pressure-induced phase transition near 15 GPa. Experiments and calculations agree in assigning the high-pressure phase to a monoclinic fergusonite-type structure. The reported results are consistent with previous powder x-ray-diffraction experiments, but are in contradiction with the conclusions obtained from earlier Raman measurements, which support the existence of more than one phase transition in the pressure range covered by our studies. The observed scheelite-fergusonite transition induces significant changes in the electronic band gap and phonon spectrum of CaMo O4 . We have determined the pressure evolution of the band gap for the low- and high-pressure phases as well as the frequencies and pressure dependencies of the Raman-active and infrared-active modes. In addition, based on calculations of the phonon dispersion of the scheelite phase, carried out at a pressure higher than the transition pressure, we propose a possible mechanism for the reported phase transition. Furthermore, from the calculations we determined the pressure dependence of the unit-cell parameters and atomic positions of the different phases and their room-temperature equations of state. These results are compared with previous experiments showing a very good agreement. Finally, information on bond compressibility is reported and correlated with the macroscopic compressibility of CaMo O4 . The reported results are of interest for the many technological applications of this oxide.

  11. High Temperature, high pressure equation of state density correlations and viscosity correlations

    Energy Technology Data Exchange (ETDEWEB)

    Tapriyal, D.; Enick, R.; McHugh, M.; Gamwo, I.; Morreale, B.


    Global increase in oil demand and depleting reserves has derived a need to find new oil resources. To find these untapped reservoirs, oil companies are exploring various remote and harsh locations such as deep waters in Gulf of Mexico, remote arctic regions, unexplored deep deserts, etc. Further, the depth of new oil/gas wells being drilled has increased considerably to tap these new resources. With the increase in the well depth, the bottomhole temperature and pressure are also increasing to extreme values (i.e. up to 500 F and 35,000 psi). The density and viscosity of natural gas and crude oil at reservoir conditions are critical fundamental properties required for accurate assessment of the amount of recoverable petroleum within a reservoir and the modeling of the flow of these fluids within the porous media. These properties are also used to design appropriate drilling and production equipment such as blow out preventers, risers, etc. With the present state of art, there is no accurate database for these fluid properties at extreme conditions. As we have begun to expand this experimental database it has become apparent that there are neither equations of state for density or transport models for viscosity that can be used to predict these fundamental properties of multi-component hydrocarbon mixtures over a wide range of temperature and pressure. Presently, oil companies are using correlations based on lower temperature and pressure databases that exhibit an unsatisfactory predictive capability at extreme conditions (e.g. as great as {+-} 50%). From the perspective of these oil companies that are committed to safely producing these resources, accurately predicting flow rates, and assuring the integrity of the flow, the absence of an extensive experimental database at extreme conditions and models capable of predicting these properties over an extremely wide range of temperature and pressure (including extreme conditions) makes their task even more daunting.

  12. Effect of high-pressure-jet processing on the viscosity and foaming properties of pasteurized whole milk. (United States)

    Tran, M; Roberts, R; Felix, T L; Harte, F M


    The processing of milk using high-pressure technologies has been shown to dissociate casein micelles, denature whey proteins, and change the appearance and rheological properties of milk. A novel high-pressure processing technology called high-pressure-jet (HPJ) processing is currently being investigated for use in the food industry. Few studies have evaluated the effects of HPJ technology on dairy foods. The present study investigated the physicochemical and foaming properties of homogenized pasteurized whole milk processed at pressures from 0 to 500 MPa using HPJ processing. The apparent particle size exhibited a monomodal distribution in whole milk samples processed up to 125 MPa and a bimodal distribution for samples processed at 250, 375, and 500 MPa. The viscosity increased from approximately 2 to 5 mPa·s when whole milk was processed using HPJ at 375 MPa, and foam expansion increased from approximately 80 to 140% after processing at >125 MPa. Foam stability was limited to pressures in the 375 to 500 MPa range. We hypothesized that the increase in apparent particle size was due to the dissociation of casein micelles into surface-active casein protein monomers, and the formation of casein-casein and casein-fat particles. Ultracentrifugation of samples into 3 milk fractions (supernatant, serum, and precipitate), and subsequent fat and protein analysis on the 3 fractions, showed that a strong interaction between casein proteins and fat triglycerides occurred, evidenced by the increase in fat content associated with the precipitate fraction with increasing pressure. This suggests that stable casein-fat aggregates are formed when whole milk is processed using HPJ at pressure >125 MPa. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Effect of Viscosity Measurement Method to Simulate High Pressure Die Casting of Thin-Wall AlSi10MnMg Alloy Castings (United States)

    Zhu, B. W.; Li, L. X.; Liu, X.; Zhang, L. Q.; Xu, R.


    In the present study, a rotating cylinder viscometer (RCV) was adopted to measure the viscosity of AlSi10MnMg aluminum alloy. The results show that the measured viscosity is much higher than previously reported viscosity of aluminum alloys measured by oscillation vessel viscometer. The viscosity measured by RCV was introduced into the simulation of the filling progress of high pressure die casting (HPDC) for thin-walled castings of aluminum alloy (TWCA). The simulated results match well with the experimental results indicating that the RCV is the most appropriate to use for simulations of HPDC for TWCA.

  14. High-pressure structural behavior of nanocrystalline Ge

    DEFF Research Database (Denmark)

    Wang, H.; Liu, J. F.; Yan, H.


    The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transi......The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse...... at the transition remains constant. Simplified models for the high-pressure structural behaviour are presented, based on the assumption that a large fraction of the atoms reside in grain boundary regions of the nanocrystalline material. The interface structure plays a significant role in affecting the transition...

  15. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions

    NARCIS (Netherlands)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; Boekel, van Tiny; Fogliano, Vincenzo; Stieger, Markus


    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were

  16. Simultaneous free-volume modeling of the self-diffusion coefficient and dynamic viscosity at high pressure

    DEFF Research Database (Denmark)

    Boned, C.; Allal, A.; Baylaucq, A.


    applied to dynamic viscosity, has been considered and generalized. In this generalized model the compound is characterized by only four parameters. But if the quadratic length is known, the number of adjustable parameters is three. The compounds considered in this work are benzene, carbon tetrachloride...

  17. High pressure behavior of Cr2O3 to 62 GPa (United States)

    Catalli, Krystle; Cynn, Hyunchae; Evans, William J.


    Corundum-structured oxides are of interest for a broad range of reasons, including their mineralogical occurrences and technological uses. The high pressure behavior of Cr2O3 is of particular interest due to the widespread use of ruby, (Al,Cr)2O3, as a pressure standard in diamond anvil cells experiments. Although there have been a number of high pressure studies on Cr2O3, discrepancies still exist among the different data sets. Here we present synchrotron X-ray diffraction data on the structure and compressional behavior of Cr2O3 to 62 GPa. Although no change in crystal structure is detected within the resolution of the measurements, a change in compressional behavior occurs near 30 GPa where Cr2O3 changes color from red to orange.

  18. Effect of high-pressure processing of bovine colostrum on immunoglobulin G concentration, pathogens, viscosity, and transfer of passive immunity to calves. (United States)

    Foster, Derek M; Poulsen, Keith P; Sylvester, Hannah J; Jacob, Megan E; Casulli, Kaitlyn E; Farkas, Brian E


    This study aimed to determine the effects of high-pressure processing on the immunoglobulin concentration, microbial load, viscosity, and transfer of passive immunity to calves when applied to bovine colostrum as an alternative to thermal pasteurization. A pilot study using Staphylococcus aureus was conducted to determine which pressure-time treatments are most appropriate for use with bovine colostrum, with the goals of maximizing bacterial inactivation while minimizing IgG content and viscosity changes. Following the pilot study, an inoculation study was conducted in which first-milking colostrum samples from Holstein-Friesian cows were inoculated with known concentrations of various bacteria or viruses and pressure processed at either 300 MPa for up to 60min or at 400MPa for up to 30min. The recovery of total native aerobic bacteria, Escherichia coli, Salmonella enterica ssp. enterica serovar Dublin, Mycobacterium avium ssp. paratuberculosis, bovine herpesvirus type 1, and feline calicivirus were determined after processing. Colostrum IgG content was measured before and after pressure processing. Shear stress and viscosity for each treatment was determined over shear rates encompassing those found during calf feeding and at normal bovine body temperature (37.8°C). Following a calf trial, serum IgG concentration was measured in 14 calves fed 4 L of colostrum pressure processed at 400MPa for 15min. In the pilot study, S. aureus was effectively reduced with pressure treatment at 300 and 400MPa (0, 5, 10, 15, 30, and 45min), with 2 treatments at 400MPa (30, 45min) determined to be inappropriate for use with bovine colostrum due to viscosity and IgG changes. High-pressure processing at 300MPa (30, 45, and 60min) and 400MPa (10, 15, and 20min) was shown to effectively reduce total native aerobic bacteria, E. coli, Salmonella Dublin, bovine herpesvirus type 1, and feline calicivirus populations in bovine colostrum, but no decrease occurred in Mycobacterium avium ssp

  19. High-pressure synthesis and structural behavior of sodium orthonitrate Na 3NO 4 (United States)

    Quesada Cabrera, R.; Sella, A.; Bailey, E.; Leynaud, O.; McMillan, P. F.


    Sodium orthonitrate (Na 3NO 4) is an unusual phase containing the first example of isolated tetrahedrally bonded NO 43- groups. This compound was obtained originally by heating together mixtures of Na 2O and NaNO 3 for periods extending up to >14 days in evacuated chambers. Considering the negative volume change between reactants and products, it was inferred that a high-pressure synthesis route might favor the formation of the Na 3NO 4 compound. We found that the recovered sample is likely to be a high-pressure polymorph, containing NO 43- groups as evidenced by Raman spectroscopy. The high-pressure behavior of Na 3NO 4 was studied using Raman spectroscopy and synchrotron X-ray diffraction in a diamond anvil cell above 60 GPa. We found no evidence for major structural transformations, even following laser heating experiments carried out at high pressure, although broadening of the Raman peaks could indicate the onset of disordering at higher pressure.

  20. Microscopic Origins of the Anomalous Melting Behavior of Sodium under High Pressure (United States)

    Eshet, Hagai; Khaliullin, Rustam Z.; Kühne, Thomas D.; Behler, Jörg; Parrinello, Michele


    X-ray diffraction experiments have shown that sodium exhibits a dramatic pressure-induced drop in melting temperature, which extends from 1000 K at ˜30GPa to as low as room temperature at ˜120GPa. Despite significant theoretical effort to understand the anomalous melting, its origins are still debated. In this work, we reconstruct the sodium phase diagram by using an ab initio quality neural-network potential. Furthermore, we demonstrate that the reentrant behavior results from the screening of interionic interactions by conduction electrons, which at high pressure induces a softening in the short-range repulsion.

  1. Experimental characterization of interfacial behaviors of hydrocarbon mixtures in high pressure systems

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Hui


    The interfacial properties and behaviors of the hydrocarbon mixtures in high pressure systems were experimentally and numerically studied during this work. Simultaneously measurements of phase densities, vapor phase compositions, and interfacial tensions were performed using the High Pressure interfacial tension facility in the Statoil Research Center, Trondheim. Numerical computations of interfacial properties at the non-homogeneous flat vapor/liquid interface were carried out with the Gradient Theory model so as to evaluate the method for future simulations of interfacial characteristics of the real gas condensate. It was found that the accuracy of the Gradient Theory is superior to the Parachor Method, which has been traditionally used in the oil industry for its interfacial tension predictions. In the laboratory, the high pressure Anton Paar oscillation tube densitometer was employed for liquid and vapor phase density measurements, and the pendant drop method was used to generate the interfacial tension data. The Online Gas Chromatography (GC) cell was utilized to obtain the vapor phase compositions under high pressure conditions. In this study, the methane + ethane + n-pentane system is considered to be a synthetic condensate, which mimics the thermodynamic behavior of a real nature gas in high pressure gas/liquid separation systems. The experimental temperature is set to 294.15 K since it is close to the scrubber' normal working temperature. Both the phase densities and interfacial tensions of the methane + n-pentane, ethane + n-pentane and methane + ethane + n-pentane systems were measured in the interfacial tension rig. The experimental data is crucial for the understanding, experimental characterizing, and developing the thermodynamic model in predicting interfacial properties and the phase behaviors governing the high pressure vapor/liquid separation process, which is the main purpose of this research. The Gradient Theory method, combined with the

  2. Phase Behavior at High Pressure of the Ternary System: CO2, Ionic Liquid and Disperse Dye

    Directory of Open Access Journals (Sweden)

    Helen R. Mazzer


    Full Text Available High pressure phase behavior experimental data have been measured for the systems carbon dioxide (CO2 + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6] and carbon dioxide (CO2 + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6] + 1-amino-2-phenoxy-4-hydroxyanthraquinone (C.I. Disperse Red 60. Measurements were performed in the pressure up to 18 MPa and at the temperature (323 to 353 K. As reported in the literature, at higher concentrations of carbon dioxide the phase transition pressure increased very steeply. The experimental data for the binary and ternary systems were correlated with good agreement using the Peng-Robinson equation of state. The amount of water in phase behavior of the systems was evaluated.

  3. High-Pressure Phase Behavior of Polycaprolactone, Carbon Dioxide, and Dichloromethane Ternary Mixture Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, JungMin; Kim, Hwayong [Seoul National University, Seoul (Korea, Republic of); Shin, Hun Yong [Seoul National University of Science and Technology, Seoul (Korea, Republic of); Kim, Soo Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)


    The high-pressure phase behavior of a polycaprolactone (Mw=56,145 g/mol, polydispersity 1.2), dichloromethane, and carbon dioxide ternary system was measured using a variable-volume view cell. The experimental temperatures and pressures ranged from 313.15 K to 353.15 K and up to 300 bar as functions of the CO{sub 2}/dichloromethane mass ratio and temperature, at poly(D-lactic acid) weight fractions of 1.0, 2.0, and 3.0%. The correlation results were obtained from the hybrid equation of state (Peng-Robinson equation of state + SAFT equation of state) for the CO{sub 2}-polymer system using the van der Waals one-fluid mixing rule. The three binary interaction parameters were optimized by the simplex method algorithm.

  4. High Pressure Behavior of Precompressed CO2 Shocked to 10 Mbar (United States)

    Crandall, L.; Rygg, J. R.; Collins, G. W.; Boehly, T. R.; Jenei, A.; Fratanduono, D. E.; Gregor, M. C.; Eggert, J. H.; Millot, M.; Spaulding, D.


    CO2 is present in the atmospheres and interiors of Jovian planets, atmospheres of exoplanets, and within Jovian moons. To study the high-pressure behavior of CO2, we used laser-driven shocks to compress CO2, to 1 TPa (10 Mbar). The CO2 was precompressed in diamond-anvil cells to 5 kbar, producing liquid at density ( 1.5 ggcm3 cm3) , and then shocked by the OMEGA Laser System. Equation of state, temperature, and optical reflectivity were measured between 150 and 950 GPa. CO2 undergoes an insulator-to-conductor transition above 200 GPa, which may be result from dissociation to metallic oxygen. These data can add to understanding of thermochemical histories of the giant planets. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Amorphization-decomposition behavior of HfW2O8 at high pressure (United States)

    Sakuntala, T.; Rao, Rekha; Garg, Alka B.; Achary, S. N.; Tyagi, A. K.


    Structural stability of HfW2O8 is investigated at high pressure using Raman spectroscopy. Irreversible amorphization is found to occur when pressurized to above 3 GPa under hydrostatic conditions. The Raman spectrum of the pressure-amorphized sample closely resembles that of amorphous WO3. On the other hand, spectrum of the recovered sample subjected to uniaxial compression of about 5 GPa showed bands characteristic of crystalline HfO2 besides the parent cubic phase and amorphous phase. Ex situ x-ray diffraction measurements on the pressure-cycled samples also indicated the presence of monoclinic HfO2. These results suggest that the observed pressure-induced amorphization (PIA) under hydrostatic compression is indeed due to hindered decomposition, which is facilitated under uniaxial compression. Thus, the behavior of HfW2O8 appears to be different from that of ZrW2O8, which exhibited only PIA and not pressure-induced decomposition at ambient temperature.

  6. Failure behavior of high pressure die casting AZ91D magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Xiong, S.M. [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084 (China); Guo, Z., E-mail: [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084 (China)


    The failure behavior of high pressure die casting AZ91D magnesium alloy during both tensile and fatigue tests was studied in situ by using scanning electron microscope. Attention was focused on the role of microstructure played in crack initiation and propagation. Results showed that the defects in castings, including gas pore, shrinkage pore and defect band, were the crack initiation sources. In tensile test, the crack propagated in a combination of intergranular and transgranular modes, and the specimen fractured by connecting defects at the section with minimum effective force bearing area. In fatigue test, the crack propagated in a transgranular mode at specific crystalline planes. When the crack was in contact with the β-phase, the crack would pass through, and fracture the network β-phase, whereas bypass the island β-phase by detaching it from the surrounding α-Mg grains. Besides, defects in front of the crack would act as the secondary crack initiation sources, from which new cracks would initiate and propagate. With the propagation of the fatigue crack, the actual maximum cyclic stress would increase to the fracture stress of the left cross section and lead to the final fracture of the specimen.

  7. High-pressure behavior of methylammonium lead iodide (MAPbI{sub 3}) hybrid perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Capitani, Francesco [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette (France); Marini, Carlo [CELLS-ALBA, Carretera B.P. 1413, Cerdanyola del Valles 08290 (Spain); Caramazza, Simone; Postorino, Paolo [Department of Physics, University “Sapienza,” Rome (Italy); Garbarino, Gaston; Hanfland, Michael [European Synchrotron Radiation Facility, Grenoble Cedex (France); Pisanu, Ambra; Quadrelli, Paolo; Malavasi, Lorenzo, E-mail: [Department of Chemistry and INSTM, University of Pavia, Pavia (Italy)


    In this paper we provide an accurate high-pressure structural and optical study of the MAPbI{sub 3} hybrid perovskite. Structural data show the presence of a phase transition toward an orthorhombic structure around 0.3 GPa followed by full amorphization of the system above 3 GPa. After releasing the pressure, the system keeps the high-pressure orthorhombic phase. The occurrence of these structural transitions is further confirmed by pressure induced variations of the photoluminescence signal at high pressure. These variations clearly indicate that the bandgap value and the electronic structure of MAPI change across the phase transition.

  8. Investigating cavity pressure behavior in high-pressure RTM process variants (United States)

    Rosenberg, P.; Chaudhari, R.; Karcher, M.; Henning, F.; Elsner, P.


    The paper addresses new variants of the high pressure resin transfer molding (HP-RTM) process namely high pressure injection RTM (HP-IRTM) and high pressure compression RTM (HP-CRTM) for manufacturing of carbon fiber reinforced composites with high fiber volume content. Both these processes utilize high-pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The paper addresses results of a study which investigated cavity pressure measurement for both the HP-RTM process variants using a specially designed highpressure RTM mold. The investigations indicate that the cavity pressure built up is a characteristic of the selected process variant. Further the relationship between the applied press force and the cavity pressure in HP-CRTM process was studied.

  9. Effect of fluid viscosity on fault frictional behavior (United States)

    Cornelio, Chiara; Violay, Marie; Spagnuolo, Elena; Di Toro, Giulio


    Fluids play an important role in fault zone and in earthquakes generation. Fluid pressure reduces the normal effective stress, lowering the frictional strength of the fault, potentially triggering earthquake ruptures. Fluid injection induced earthquakes, such as in geothermal reservoir, are direct evidence of the effect of fluid pressure on the fault strength. However, the frictional fault strength may also vary due to the chemical and physical characteristics of the fluid as discussed here. Here we performed two series of experiments on precut samples of Westerly granite to investigate the role of fluid viscosity on fault frictional behavior. In the first series, we performed 20 rotary shear experiments with the machine SHIVA (INGV, Rome) on cylindrical (50 mm external diameter), at slip rate (V) ranging from 10 μ m/s to 1 m/s effective normal stress (P) of 10 MPa and pore pressure varying from 0 ( i.e., dry conditions) to 2 MPa. Three different fluid viscosities were tested using pure distilled water (η=1 mPa\\cdot s), 40{%}water/60{%}glycerol (η =10.5 mPa\\cdot s) and 15{%}water/85{%}glycerol (η=109 mPa\\cdot s) mixtures (all reported viscosities at 20 rC). In agreement with theoretical argumentations (Stribeck curve) we distinguished three lubrication regimes. At low product of slip-rate per fluid viscosity (S= η\\cdot V/P

  10. Thermal behavior of Nickel deformed to ultra-high strain by high pressure torsion

    DEFF Research Database (Denmark)

    Zhang, Hongwang; Huang, Xiaoxu; Pippan, Richard


    Polycrystalline Ni (99.5 %) has been deformed to an ultra-high strain of εvM=100 (εvM, von Mises strain) by high pressure torsion (HPT) at room temperature. The deformed sample is nanostructured with an average boundary spacing of 90 nm, a high density of dislocations of >1015m-2 and a large...

  11. Anomalous compressive behavior in CeO2 nanocubes under high pressure

    DEFF Research Database (Denmark)

    Ge, M. Y.; Fang, Y. Z.; Wang, H.


    High-pressure angle-dispersive x-ray diffraction measurements have been performed on bulk and nanocrystalline cubic CeO2 with mean sizes of 4.7 and 5.6 nm. It is found that the compressibility of the nanocrystals is lower than the bulk when a threshold pressure is reached. This critical pressure ...

  12. High pressure behavior of ZrW2O8: Gruneisen parameter and thermal properties (United States)

    Ravindran; Arora; Mary


    High pressure Raman spectroscopic studies are carried out on negative thermal expansion material ZrW2O8. The system exhibits amorphization at 2.2+/-0.3 GPa via an intermediate orthorhombic phase. In the cubic phase most modes below 50 meV are found to have negative Gruneisen parameter. Using the reported phonon density of states thermal properties are calculated and compared with the reported results. In contrast to the earlier belief, the present results show that modes of energies much higher than 10 meV also contribute substantially to the negative thermal expansion.

  13. The high-pressure behavior of an Al- and Fe-rich natural orthopyroxene

    DEFF Research Database (Denmark)

    Nestola, F.; Boffa Ballaran, T.; Balic Zunic, Tonci


    A single crystal of a natural orthopyroxene with composition M2[Fe2+0.818Mg0.156Ca0.010Mn0.016]M1[Fe2+0.081 Mg0.767Al0.084Fe3+0.068]TA[Si]TB[Si0.848Al0.152]O6 and space group Pbca (sample S95) was investigated at high pressure by X-ray diffraction using a diamond-anvil cell up to 9.56 GPa. No phase...

  14. A Numerical and Experimental Study of Flow Behavior in High Pressure Die Casting (United States)

    Saeedipour, Mahdi; Schneiderbauer, Simon; Pirker, Stefan; Bozorgi, Salar

    High pressure die casting (HPDC) is one of the most important and yet little known manufacturing methods especially during liquid metal injection and filling phase. During its application different problems can arise: on the one hand, wavy disintegration of the jet might result in cold shut defect in the final product, on the other hand a high degree of atomization may strongly increase the porosity defect. A numerical simulation using volume of fluid approach (VOF), is carried out to model the global spreading of liquid metal jet. The formation of droplets, which are usually smaller than the grid spacing in computational domain, is determined by a surface energy-based criterion. An Eulerian-Lagrangian framework is introduced to track and model the droplets after formation. Since liquid metal is hardly to access, we performed experiments based on water analogy to capture the flow regime changes and drop formation. The comparison between numerical results and experiments shows a very good agreement.

  15. High-pressure shock behavior of WC and Ta2O5 powders.

    Energy Technology Data Exchange (ETDEWEB)

    Knudson, Marcus D. (Sandia National Laboratories, Albuquerque, NM); Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Root, Seth (Sandia National Laboratories, Albuquerque, NM)


    Planar shock experiments were conducted on granular tungsten carbide (WC) and tantalum oxide (Ta{sub 2}O{sub 5}) using the Z machine and a 2-stage gas gun. Additional shock experiments were also conducted on a nearly fully dense form of Ta{sub 2}O{sub 5}. The experiments on WC yield some of the highest pressure results for granular materials obtained to date. Because of the high distention of Ta{sub 2}O{sub 5}, the pressures obtained were significantly lower, but the very high temperatures generated led to large contributions of thermal energy to the material response. These experiments demonstrate that the Z machine can be used to obtain accurate shock data on granular materials. The data on Ta{sub 2}O{sub 5} were utilized in making improvements to the P-{lambda} model for high pressures; the model is found to capture the results not only of the Z and gas gun experiments but also those from laser experiments on low density aerogels. The results are also used to illustrate an approach for generating an equation of state using only the limited data coming from nanoindentation. Although the EOS generated in this manner is rather simplistic, for this material it gives reasonably good results.

  16. Structural evolution behavior of manganese monophosphide under high pressure: experimental and theoretical study (United States)

    Yu, Zhenhai; Wu, Wei; Lu, Pengchao; Zhao, Jinggeng; Cheng, Jinguang; Hu, Qingyang; Yuan, Ye; Li, Xin; Pei, Cuiying; Chen, Fengjiao; Yan, Zhipeng; Yan, Shuai; Yang, Ke; Sun, Jian; Luo, Jianlin; Wang, Lin


    The influence of external pressure on the structural properties of manganese monophosphides (MnP) at room temperature has been studied using in situ angle dispersive synchrotron x-ray powder diffraction (AD-XRD) with a diamond anvil cell. The crystal structure of MnP is stable between 0 to 15 GPa. However, the compressibility of b-axis is much larger than those of a- and c-axes. From this result we suggested that the occurrence of superconductivity in MnP was induced by suppression of the long-range antiferromagnetically ordered state rather than a structural phase transition. Furthermore, the present experimental results show that the Pnma phase of MnP undergoes a pressure-induced structural phase transition at ~15.0 GPa. This finding lighted up-to-date understanding of the common prototype B31 structure (Strukturbericht Designation: B31) in transition metal monophosphides. No additional structural phase transition was observed up to 35.1 GPa (Run 1) and 40.2 GPa (Run 2) from the present AD-XRD results. With an extensive crystal structure searching and ab initio calculations, we predict that MnP underwent two pressure-induced structural phase transitions of Pnma  →  P213 and P213  →  Pm-3m (CsCl-type) at 55.0 and 92.0 GPa, respectively. The structural stability and the electronic structures of manganese monophosphides under high pressure are also briefly discussed.

  17. High-pressure behavior of djerfisherite: Implication for its origin in diamonds and mantle xenoliths (United States)

    Minin, D.; Sharygin, I.; Litasov, K.; Sharygin, V.; Shatskiy, A.; Ohtani, E.


    Djerfisherite K6(Fe,Cu,Ni)25S26Cl is a widespread mineral in kimberlite-hosted mantle xenoliths and diamonds. It usually occurs as rims around primary Fe-Ni-Cu sulfides. It is assumed that metasomatic origin of djerfisherite is related to interaction of primary sulfides with the hypothetical K-Cl-rich fluid or melt. However, source and composition of metasomatic agent as well as PT-conditions of the interaction is unclear. There are two basic hypothesis of djerfisherite origin in diamonds and mantle xenoliths: (1) in-situ mantle metasomatism; (2) infiltration of kimberlite melt into mantle nodules during magma ascent. To date, djerfisherite was synthesized only at 1 atm and 350-650 oC (Clarke, 1979) and at 0.1 GPa and 470 oC (Gorbachev and Nekrasov, 1980). We performed first experimental study on the stability of this sulfide at high pressures. The experiments were performed at 3 GPa nd 800-1200 oC. Also we have planned to perform experiments at 6 GPa, however, it was not necessary due to instability of djerfisherite at lower pressures. As starting materials we used natural Cu-rich djerfisherite from peralkaline pegmatites of Khibina massif (Kola peninsula, Russia) and synthetic mixtures with the following compositions (in mol.%) (Fe18Cu2Ni5)25S26 + 5KCl + 3.5K2CO3 and (Fe18Cu2Ni5)25S26 + 6KCl + K2CO3 + 3.5Na2CO3 + 8Mg2SiO4. Potassium content was in excess by an addition of K2CO3. Sulfide portion of synthetic mixtures compositionally corresponds to djerfisherite in diamonds and mantle xenoliths. The results of experiments showed that djerfisherite is unstable at 3 GPa, or higher pressures. This indicates that djerfisherite in diamond, diamond-bearing garnet peridotite could not be crystallized in cratonic lithosphere mantle in-situ. Consequently, djerfisherite formation in mantle nodules is a result of their interaction with kimberlite melt during ascent of magma at the subsurface conditions. Instead of djerfisherite we synthesized two new potassium sulfides: K0

  18. High pressure behavior of phlogopite using neutron diffraction and first principle simulations (United States)

    Chheda, T. D.; Mookherjee, M.; dos Santos, A. M.; Molaison, J.; Manthilake, G. M.; Chantel, J.; Mainprice, D.


    Hydrous phases play an important role in the deep water cycle by transporting water into the Earth's interior. Upon, reaching their thermodynamic stability, these hydrous phases decompose and release the water. A part of the water is cycled back to the arc, thus completing the deep water cycle, the remaining water is partitioned into dense hydrous phases and nominally anhydrous phases. Hence, in order to understand the role the hydrous phases in the deep water cycle, it is important to constrain the effect of pressure, temperature, and chemistry on the thermodynamic stability of the hydrous phases. In addition, it is important to constrain the elasticity of these hydrous phases to test whether they can explain the distinct geophysical observations such as lower bulk sound velocities and elastic anisotropy. Phlogopite is a potassium bearing mica that is stable in the hydrated crust and metasomatized mantle up to pressures of ~9 GPa, i.e., base of the upper mantle. We investigated the response of the crystal structure, lattice parameters and unit-cell volume of a natural phlogopite upon compression. We conducted in situ neutron diffraction studies at high-pressures using Paris-Edinburgh press at the Spallation Neutrons and Pressure Diffractometer (SNAP), Oak Ridge National Laboratory. All the experiments were conducted at room temperatures and pressures up to 10 GPa were explored. The equation of state parameters from our experiments could be explained by a finite strain formulation with V0= 487 Å3, K0 = 49 GPa, K' = 4.1. In addition, we have used first principle simulations based on density functional theory to calculate the equation of state and elasticity. The predicted equation of state is in good agreement with the experiments, with V0= 519 Å3, K0 = 45.8 GPa and K'= 6.9. The full elastic constant tensor shows significant anisotropy with the principal elastic constants at theoretical V0: C11= 181 GPa, C22= 185 GPa, C33= 62 GPa, the shear elastic constants- C44

  19. Phase Behavior of Three PBX Elastomers in High-Pressure Chlorodifluoromethane (United States)

    Lee, Byung-Chul


    The phase equilibrium behavior data are presented for three kinds of commercial polymer-bonded explosive (PBX) elastomers in chlorodifluoromethane (HCFC22). Levapren^{{registered }} ethylene- co-vinyl acetate (LP-EVA), HyTemp^{{registered }} alkyl acrylate copolymer (HT-ACM), and Viton^{{registered }} fluoroelastomer (VT-FE) were used as the PBX elastomers. For each elastomer + HCFC22 system, the cloud point (CP) and/or bubble point (BP) pressures were measured while varying the temperature and elastomer composition using a phase equilibrium apparatus fitted with a variable-volume view cell. The elastomers examined in this study indicated a lower critical solution temperature phase behavior in the HCFC22 solvent. LP-EVA showed the CPs at temperatures of 323 K to 343 K and at pressures of 3 MPa to 10 MPa, whereas HT-ACM showed the CPs at conditions between 338 K and 363 K and between 4 MPa and 12 MPa. For the LP-EVA and HT-ACM elastomers, the BP behavior was observed at temperatures below about 323 K. For the VT-FE + HCFC22 system, only the CP behavior was observed at temperatures between 323 K and 353 K and at pressures between 6 MPa and 21 MPa. As the elastomer composition increased, the CP pressure increased, reached a maximum value at a specific elastomer composition, and then remained almost constant.

  20. New Outlook on the High-Pressure Behavior of Pentaerythritol Tetranitrate (United States)


    H.; Smith, L. C. Studies on the Polymorphs of HMX . Los Alamos Technical Report No. LAMS-2652, 1962. 2. Halleck, P. M.; Wackerle, J. Dynamic...temperature and pressure is crucial to addressing issues related to sensitivity, performance, and safety. Polymorphic phases of energetic materials...observed at ambient conditions (1). As a result of the different physical behaviors of the polymorphs , during extreme conditions, a deeper

  1. The high-pressure behavior of spherocobaltite (CoCO3): a single crystal Raman spectroscopy and XRD study (United States)

    Chariton, Stella; Cerantola, Valerio; Ismailova, Leyla; Bykova, Elena; Bykov, Maxim; Kupenko, Ilya; McCammon, Catherine; Dubrovinsky, Leonid


    Magnesite (MgCO3), calcite (CaCO3), dolomite [(Ca, Mg)CO3], and siderite (FeCO3) are among the best-studied carbonate minerals at high pressures and temperatures. Although they all exhibit the calcite-type structure ({R}\\bar{3}{c} ) at ambient conditions, they display very different behavior at mantle pressures. To broaden the knowledge of the high-pressure crystal chemistry of carbonates, we studied spherocobaltite (CoCO3), which contains Co2+ with cation radius in between those of Ca2+ and Mg2+ in calcite and magnesite, respectively. We synthesized single crystals of pure spherocobaltite and studied them using Raman spectroscopy and X-ray diffraction in diamond anvil cells at pressures to over 55 GPa. Based on single crystal diffraction data, we found that the bulk modulus of spherocobaltite is 128 (2) GPa and K' = 4.28 (17). CoCO3 is stable in the calcite-type structure up to at least 56 GPa and 1200 K. At 57 GPa and after laser heating above 2000 K, CoCO3 partially decomposes and forms CoO. In comparison to previously studied carbonates, our results suggest that at lower mantle conditions carbonates can be stable in the calcite-type structure if the radius of the incorporated cation(s) is equal or smaller than that of Co2+ (i.e., 0.745 Å).

  2. Experimental and Theoretical Investigation of the High-Pressure Behavior of Concrete (United States)


    hydrostatic test results on small mortar size specimens. There is a large body of literature on modeling the behavior of cementitious materials. For moderate...for WES5000 concrete. Item Mixture proportions, saturated surface–dry Type I Portland cement 264.0kg/m3 Flyash 55.8kg/m3 9.5mm local unprocessed chert...analysis of compaction of concrete and mortar . International Journal for Numerical and Analytical Methods in Geomechanics 2001; 25:1467–1486. 8

  3. Anomalous compression behavior in a C15 Laves compound CeAl2 under high pressure (United States)

    Tateno, Shota; Kishii, Nobuya; Ohashi, Masashi; Miyagawa, Hidenori; Oomi, Gendo; Satoh, Isamu; Miyajima, Nobuyoshi; Yagi, Takehiko


    Although there have been quite a number of discrepancies in the compression curves of CeAl2, such results come from the lattice compression at non-hydrostatic condition by solidification of pressure transmitting medium. We have carried out the powder X-ray diffraction measurement of CeAl2 under hydrostatic pressure with helium gas as pressure-transmitting medium which achieves the best hydrostatic conditions. Although no splitting of the peak is observed in the present diffraction pattern, it is found that a full width at half maximum is enhanced above 20 GPa for several Bragg reflections. Such behaviors suggest the existence of a new pressure-induced structural phase transition which is not observed in the previous reports under non-hydrostatic pressure.

  4. First-principles study on the high-pressure behavior of the zone-center modes of lonsdaleite silicon (United States)

    Wu, B. R.


    Using a first-principles method, I have studied the static and vibrational properties of the lonsdaleite-silicon. The frequencies of the Raman active modes of the lonsdaleite-Si at ambient pressure agree very well with the experimental results. Among these Raman active modes, the E2g mode can be an indication mode of the lonsdaleite-Si. The high-pressure behavior of the zone-center modes of the lonsdaleite-Si is first studied and a pressure-induced mode softening is found. The E2u mode of the lonsdaleite-Si exhibits red shift under compression and its frequency decreases to zero as the applied pressure increases to around 14 GPa. The pressure-induced mode softening of the E2u mode indicates that the lonsdaleite-Si has a phase transition before the applied pressure reaches 14 GPa.

  5. Fatigue Behavior of an Ultrafine-Grained Al-Mg-Si Alloy Processed by High-Pressure Torsion

    Directory of Open Access Journals (Sweden)

    Maxim Murashkin


    Full Text Available The paper presents the evaluation of the mechanical and fatigue properties of an ultrafine-grained (UFG Al 6061 alloy processed by high-pressure torsion (HPT at room temperature (RT. A comparison is made between the UFG state and the coarse-grained (CG one subjected to the conventional aging treatment Т6. It is shown that HPT processing leads to the formation of the UFG microstructure with an average grain size of 170 nm. It is found that yield strength (σ0.2, ultimate tensile strength (σUTS and the endurance limit (σf in the UFG Al 6061 alloy are higher by a factor of 2.2, 1.8 and 2.0 compared to the CG counterpart subjected to the conventional aging treatment Т6. Fatigue fracture surfaces are analyzed, and the fatigue behavior of the material in the high cycle and low cycle regimes is discussed.

  6. Simultaneous observations of reaction kinetics, creep behavior, and AE activities during syndeformational antigorite dehydration at high pressures (United States)

    Kubo, T.; Iwasato, T.; Higo, Y.; Kato, T.; Kaneshima, S.; Uehara, S.; Koizumi, S.; Imamura, M.; Tange, Y.


    Intermediate-depth earthquakes are seismic activities in Wadati-Benioff zone at depths from 60 km to 300 km, where subducting plates deform plastically rather than brittle failure. Although it has been reported that unstable faulting occurred during antigorite dehydration even at higher pressures than ~2 GPa (e.g., Jung et al., 2009), the recent study by Chernak and Hirth (2011) revealed that the syndefromational antigorite dehydration does not produces stick-slip instabilities but stable fault slip. In the present study, we newly developed an AE monitoring system for high-pressure reaction-deformation processes combined with D-DIA and synchrotron monochromatic X-ray to observe reaction kinetics, creep behaviors, and AE activities simultaneously. We applied this technique to investigate shear instability during syndeformational antigorite dehydration. High-pressure deformation experiments were conducted up to ~8 GPa, ~1050 K, and strain rates of 3.4-9.2 x 10-5 s-1 in compression using a D-DIA type apparatus installed at BL-04B1, SPring-8. 50 keV mono X-ray were used to measure reaction kinetics and stress-strain data. To monitor shear instabilities by detecting AEs, six piezoelectric devices were positioned between first and second stage anvils of MA 6-6 type system. We used three kinds of starting materials of polycrystalline antigorite, fine-grained forsterite polycrystal, and two-phase mixtures of antigorite and San Carlos olivine (10%, 30%, and 50%atg). Clear contrasts were observed in AE activities between forsterite and antigorite samples. AE activities detected within the forsterite polycrystal suggested (semi) brittle behaviors at low pressures during the cold compression stage.
Almost no AEs were detected within the antigorite samples during any stages of cold compression, ramping, deformation, and syndeformational dehydration although localized deformation textures were observed in recovered samples. Instead, we detected some AEs outside the sample

  7. Phase behavior for the poly(alkyl methacrylate)+supercritical CO{sub 2}+DME mixture at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Seok; Chio, Sang-Won; Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)


    The phase behavior curves of binary and ternary system were measured for poly(alkyl methacrylate) in supercritical CO{sub 2}, as well as for the poly(alkyl methacrylate)+dimethyl ether (DME) (or 1-butene) in CO{sub 2}. The solubility curves are reported for the poly(alkyl methacrylate)+DME in supercritical CO{sub 2} at temperature from (300 to 465) K and a pressure from (3.66 to 248) MPa. Also, The high-pressure static-type apparatus of cloud-point curve was tested by comparing the measured phase behavior data of the poly(methyl methacrylate) [PMMA]+CO{sub 2}+20.0 and 30.4 wt% methyl methacrylate (MMA) system with literature data of 10.4, 28.8 and 48.4 wt% MMA concentration. The phase behavior data for the poly(alkyl methacrylate)+CO{sub 2}+DME mixture were measured in changes of the pressure-temperature (p, T) slope and with DME concentrations. Also, the cloud-point pressure for the poly(alkyl methacrylate)+1- butene solution containing supercritical CO{sub 2} shows from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region at concentration range from (0.0 to 95) wt% 1-butene at below 455 K and at below 245MPa.

  8. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)


    According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO2 emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H2). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

  9. Viscosity and Softening Behavior of Alkali Zinc Sulfophosphate Glasses

    DEFF Research Database (Denmark)

    Da, Ning; Krolikowski, Sebastian; Nielsen, Karsten Hansgaard


    We report on the softening properties and viscosity of glasses from the system ZnO-Na2O-SO3-P2O5 for low-temperature sealing applications. Up to a ratio of network-forming ions PO(4)3-:SO(4)2- of about 2:1, a gradual substitution of P2O5 by SO3 results in decreasing glass transition and softening...... the macroscopic glass transition temperature, which is interpreted as a result of the formation of an increasingly interconnected assembly of SO(4)2- and PO(4)3- units with increasing SO3 content....

  10. Structural behavior of Tl-exchanged natrolite at high pressure depending on the composition of pressure-transmitting medium (United States)

    Seryotkin, Yu. V.; Bakakin, V. V.; Likhacheva, A. Yu.; Dementiev, S. N.; Rashchenko, S. V.


    The structural evolution of Tl-exchanged natrolite with idealized formula Tl2[Al2Si3O10]·2H2O, compressed in penetrating (water:ethanol 1:1) and non-penetrating (paraffin) media, was studied up to 4 GPa. The presence of Tl+ with non-bonded electron lone pairs, which can be either stereo-chemically active or passive, determines distinctive features of the high-pressure behavior of the Tl-form. The effective volume of assemblages Tl+(O,H2O) n depends on the E-pairs activity: single-sided coordination correlates with smaller volumes. At ambient conditions, there are two types of Tl positions, only one of them having a nearly single-sided coordination as a characteristic of stereo-activity of the Tl+ E pair. Upon the compression in paraffin, a phase transition occurs: a 5% volume contraction of flexible natrolite framework is accompanied by the conversion of all the Tl+ cations into stereo-chemically active state with a single-sided coordination. This effect requires the reconstruction of all the extra-framework subsystems with the inversion of the cation and H2O positions. The compression in water-containing medium leads to the increase of H2O content up to three molecules pfu through the filling of partly vacant positions. This hinders a single-sided coordination of Tl ions and preserves the configuration of their ion-molecular subsystem. It is likely that the extra-framework subsystem is responsible for the super-structure modulation.

  11. Interfacial heat transfer behavior at metal/die in finger-plated casting during high pressure die casting process

    Directory of Open Access Journals (Sweden)

    Wen-bo Yu


    Full Text Available Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process (HPDC, the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux (q and interfacial heat transfer coefficient (h. Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW昺-2 and 64.3 kW昺-2昁-1, respectively. The simulation of melt flow in the die reveals that the thinnest (T1 finger plate could accelerate the melt flow from 50 m晄-1 to 110 m晄-1. Due to this high velocity, the interfacial heat flux at the end of T1 could firstly reach a highest value 7.92 MW昺-2 among the ends of Tn (n=2,3,4,5. In addition, the qmax and hmax values of T2, T4 and T5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient (h, the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction (f.

  12. High-pressure structural behavior of the double perovskite Sr2CrReO6: an experimental and theoretical study

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Vaitheeswaran, G.


    The high-pressure structural behavior of Sr2CrReO6 has been studied experimentally using synchrotron radiation and the diamond anvil cell and theoretically using density functional theory. The experimental zero-pressure bulk modulus is B0=1704GPa and the pressure derivative is B0'=4.71.0. These r...

  13. The Effect of Aluminum Content and Processing on the Tensile Behavior of High Pressure Die Cast Mg Alloys (United States)

    Deda, Erin M.

    Due to their high specific strength and good castability, magnesium alloys are desirable for use in weight reduction strategies in automotive applications. However, the mechanical properties of high pressure die cast (HPDC) magnesium can be highly variable and dependent on location in the casting. To better understand the relationship between microstructure and tensile properties, the influence of alloying and section thickness on the microstructural features and tensile properties of Mg-Al and Mg-Al-Mn alloys is quantified. This investigation provides experimental input to modeling activities for the development of an Integrated Computational Materials Engineering capability, to assess and quantify the impact of microstructure on the tensile behavior of HPDC Mg AM series (magnesium-aluminum-manganese) alloys. As a result of this work, it is found that with increasing aluminum content, the yield strength increases and the ductility decreases. Increasing the plate thickness results in a decrease in both the yield strength and ductility. HPDC components have varying microstructural features through the plate thickness, developing a "skin" and "core". The grain size, beta-Mg 17Al12 phase, and solute content are all quantified through the thickness of the plates. By quantifying microstructural variations, a physics-based model has been developed which is able to predict the effects of alloying and plate thickness on yield strength. The primary factors affecting strengthening are accounted for using a linear superposition model of solid solution, grain size, and dispersion hardening. This model takes into account through-thickness microstructure gradients that exist in HPDC components by using a composite model to incorporate the skin and core changes. The yield strength in these alloys is dominated by grain boundary strengthening and solute hardening effects. In order to isolate the effects of eutectic phases, shrinkage porosity and oxide films on strength and

  14. Experimental and Simulation Studies of Strength and Fracture Behaviors of Wind Turbine Bearing Steel Processed by High Pressure Torsion

    Directory of Open Access Journals (Sweden)

    Ning Wang


    Full Text Available White structure flaking (WSF has been found to be one of the failure modes in bearing steels under rolling contacts through the formation of cracks associated with a microstructural change called white etching area (WEA. In the present research, the effects of the high-pressure torsion (HPT process on the microstructure and mechanical properties of an AISI 52100 alloy are studied. An annealed AISI 52100 was subjected to high-pressure torsion at room temperature under a pressure of up to ~6 GPa for up to three turns. Finite-element modeling (FEM was used to simulate the process under high-pressure torsion and quasi-constrained conditions to reveal the material property changes occurring in HPT. Scanning electron microscopy and microhardness testing after processing were used to investigate the microstructural and mechanical property evolution of the steel. Strain induced microstructural transformations occur and affect the mechanical properties in a similar way to the well-known white etching area (WEA found beneath the surface of wind turbine bearings. Here, HPT is used to study the feasibility of creating microstructural changes that are similar to WEA. This paper presents the preliminary results of using HPT to produce WEAs.

  15. Experimental measurement and correlation of phase behavior for the CO{sub 2}+heptafluorobutyl acrylate and CO{sub 2}+heptafluorobutyl methacrylate systems at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Soon-Do; Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)


    Experimental data of high pressure phase behavior from 313.2 to 393.2 K and pressures up to about 14.3 MPa were reported for binary mixture of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) in supercritical carbon dioxide. The high pressure experiment was performed by static method using variable-volume view cell apparatus. The CO{sub 2}+HFBA and CO{sub 2}+HFBMA systems are correlated with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule. The CO{sub 2}+HFBA and CO{sub 2}+HFBMA systems exhibit type-I phase behavior with continuous critical mixture curves.


    Directory of Open Access Journals (Sweden)

    Arkan J. Hadi


    Full Text Available In the present study a thermodynamic model for prediction of gas-liquid equilibrium at high pressures and different temperatures prepared for the binary systems of carbon dioxide (1 with each of the one of the liquid physical solvents (2 (sulfolane, n-methyl-2-pyrrolidone and propylene carbonate using Peng-Robenson equation of state (PR-EOS with different mixing rules to show the effect of the type of mixing rule used.Comparison of the experimental phase equilibrium data in the literature with the results of the model showed very good representation for some mixing rules and good for the others.

  17. High Pressure Behavior of ZrW2O8: Grüneisen Parameter and Thermal Properties (United States)

    Ravindran, T. R.; Arora, Akhilesh K.; Mary, T. A.


    High pressure Raman spectroscopic studies are carried out on negative thermal expansion material ZrW2O8. The system exhibits amorphization at 2.2+/-0.3 GPa via an intermediate orthorhombic phase. In the cubic phase most modes below 50 meV are found to have negative Grüneisen parameter. Using the reported phonon density of states thermal properties are calculated and compared with the reported results. In contrast to the earlier belief, the present results show that modes of energies much higher than 10 meV also contribute substantially to the negative thermal expansion.

  18. Tunable high pressure lasers (United States)

    Hess, R. V.


    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  19. Viscosity and sedimentation behaviors of the magnetorheological suspensions with oleic acid/dimer acid as surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jianjian; Yan, Hua; Hu, Zhide; Ding, Ding


    This work deals with the role of polar interactions on the viscosity and sedimentation behaviors of magnetorheological suspensions with micro-sized magnetic particles dispersed in oil carriers. The oleic acid and dimer acid were employed to make an adjustment of the hydrophobicity of iron particles, in the interest of performing a comparative evaluation of the contributions of the surface polarity. The viscosity tests show that the adsorbed surfactant layer may impose a hindrance to the movement of iron particles in the oil medium. The polar attractions between dimer acid covered particles gave rise to a considerable increase in viscosity, indicating flocculation structure developed in the suspensions. The observed plateau-like region in the vicinity of 0.1 s{sup −1} for MRF containing dimer acid is possibly due to the flocculation provoked by the carboxylic polar attraction, in which the structure is stable against fragmentation. Moreover, a quick recovery of the viscosity and a higher viscosity-temperature index also suggest the existence of particle-particle polar interaction in the suspensions containing dimer acid. The sedimentation measurements reveal that the steric repulsion of oleic acid plays a limited role in the stability of suspensions only if a large quantity of surfactant was used. The sedimentation results observed in the dimer acid covered particles confirm that loose and open flocculation was formed and enhanced sedimentation stability. - Highlights: • Surfactants were employed to make adjustments of the hydrophobicity of particles. • Polar attractions between particles increased the viscosity considerably. • Loose and open flocculation was formed in CI/DA suspension. • The steric repulsion of oleic acid played a limited role in the stability.

  20. Predicting Stress vs. Strain Behaviors of Thin-Walled High Pressure Die Cast Magnesium Alloy with Actual Pore Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Sil; Barker, Erin; Cheng, Guang; Sun, Xin; Forsmark, Joy; Li, Mei


    In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to the experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results. This indicates that the developed 3D extrinsic modeling method may be used to examine the influence of various aspects of pore sizes/distributions as well as intrinsic properties (i.e., matrix properties) on the ductility/fracture of Mg castings.

  1. Hydrostatic Compression Behavior and High-Pressure Stabilized β-Phase in γ-Based Titanium Aluminide Intermetallics

    Directory of Open Access Journals (Sweden)

    Klaus-Dieter Liss


    Full Text Available Titanium aluminides find application in modern light-weight, high-temperature turbines, such as aircraft engines, but suffer from poor plasticity during manufacturing and processing. Huge forging presses enable materials processing in the 10-GPa range, and hence, it is necessary to investigate the phase diagrams of candidate materials under these extreme conditions. Here, we report on an in situ synchrotron X-ray diffraction study in a large-volume press of a modern (α2 + γ two-phase material, Ti-45Al-7.5Nb-0.25C, under pressures up to 9.6 GPa and temperatures up to 1686 K. At room temperature, the volume response to pressure is accommodated by the transformation γ → α2, rather than volumetric strain, expressed by the apparently high bulk moduli of both constituent phases. Crystallographic aspects, specifically lattice strain and atomic order, are discussed in detail. It is interesting to note that this transformation takes place despite an increase in atomic volume, which is due to the high ordering energy of γ. Upon heating under high pressure, both the eutectoid and γ-solvus transition temperatures are elevated, and a third, cubic β-phase is stabilized above 1350 K. Earlier research has shown that this β-phase is very ductile during plastic deformation, essential in near-conventional forging processes. Here, we were able to identify an ideal processing window for near-conventional forging, while the presence of the detrimental β-phase is not present under operating conditions. Novel processing routes can be defined from these findings.

  2. The role of the Sb3+ lone-electron pairs and Fe2+ coordination in the high-pressure behavior of berthierite

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Balic Zunic, Tonci; Nestola, Fabrizio


    A single crystal of natural berthierite, FeSb2S4, was investigated at high pressure by means of X-ray diffraction using a diamond-anvil cell equipped with diamond backing plates. No phase transitions were indicated up to 8 GPa. The third-order Birch–Murnaghan equation of state, calculated using...... high-accuracy volume–pressure data up to 8.05 GPa, gave the following coefficients: V0 = 608.78(7) Å3, KT0 = 37.2(2) GPa and K’ = 7.0(1). The evolution of the structure as a function of pressure has been determined at seven different pressures up to 7.41 GPa. As in other structures...... at higher pressures. This deformation at high pressures can be related to an increase in the Jahn–Teller effect on the Fe2+ coordination. The influence of Fe on compressional behavior makes a distinct difference between the compression of berthierite and that of stibnite, Sb2S3. The bridging Fe coordination...

  3. High-pressure microfluidics (United States)

    Hjort, K.


    When using appropriate materials and microfabrication techniques, with the small dimensions the mechanical stability of microstructured devices allows for processes at high pressures without loss in safety. The largest area of applications has been demonstrated in green chemistry and bioprocesses, where extraction, synthesis and analyses often excel at high densities and high temperatures. This is accessible through high pressures. Capillary chemistry has been used since long but, just like in low-pressure applications, there are several potential advantages in using microfluidic platforms, e.g., planar isothermal set-ups, large local variations in geometries, dense form factors, small dead volumes and precisely positioned microstructures for control of reactions, catalysis, mixing and separation. Other potential applications are in, e.g., microhydraulics, exploration, gas driven vehicles, and high-pressure science. From a review of the state-of-art and frontiers of high pressure microfluidics, the focus will be on different solutions demonstrated for microfluidic handling at high pressures and challenges that remain.

  4. High pressure studies of molecular lumenescence

    Energy Technology Data Exchange (ETDEWEB)

    Drickamer, H.G.


    The studies of high pressure molecular luminescence reviewed, along with results for inorganic systems discussed elsewhere, provide evidence about the versatility and power of high pressure as a tool for characterizing electronic states, testing theories concerning electronic phenomena, and generally obtaining a better understanding of electronic behavior in condensed systems. 16 figures.

  5. Corrosion Behavior of High Pressure Die Cast Al-Ni and Al-Ni-Ca Alloys in 3.5% NaCl Solution

    Energy Technology Data Exchange (ETDEWEB)

    Arthanari, Srinivasan; Jang, Jae Cheol; Shin, Kwang Seon [Seoul National University, Seoul (Korea, Republic of)


    In this investigation corrosion behavior of newly developed high-pressure die cast Al-Ni (N15) and Al-Ni-Ca (NX1503) alloys was studied in 3.5% NaCl solution. The electrochemical corrosion behavior was evaluated using open circuit potential (OCP) measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization results validated that NX1503 alloy exhibited lower corrosion current density (i{sub corr}) value (5.969 μA/cm{sup 2}) compared to N15 (7.387 μA/cm{sup 2}). EIS-Bode plots revealed a higher impedance (|Z|) value and maximum phase angle value for NX1503 than N15 alloy. Equivalent circuit curve fitting analysis revealed that surface layer (R{sub 1}) and charge transfer resistance (R{sub ct}) values of NX1503 alloy was higher compared to N15 alloy. Immersion corrosion studies were also conducted for alloys using fishing line specimen arrangement to simultaneously measure corrosion rates from weight loss (P{sub W}) and hydrogen volume (P{sub H}) after 72 hours and NX1503 alloy had lower corrosion rate compared to N15 alloy. The addition of Ca to N15 alloy significantly reduced the Al{sub 3}Ni intermetallic phase and further grain refinement may be attributed for reduction in the corrosion rate.

  6. Effect of Hydrostatic Pressure on the 3D Porosity Distribution and Mechanical Behavior of a High Pressure Die Cast Mg AZ91 Alloy (United States)

    Sket, Federico; Fernández, Ana; Jérusalem, Antoine; Molina-Aldareguía, Jon M.; Pérez-Prado, María Teresa


    A limiting factor of high pressure die cast (HPDC) Mg alloys is the presence of porosity, which has a detrimental effect on the mechanical strength and gives rise to a large variability in the ductility. The application of hydrostatic pressure after casting is known to be beneficial to improve the mechanical response of HPDC Mg alloys. In this study, a combined experimental and simulation approach has been developed in order to investigate the influence of pressurization on the 3D porosity distribution and on the mechanical behavior of an HPDC Mg AZ91 alloy. Examination of about 10,000 pores by X-ray computed microtomography allowed determining the effect of hydrostatic pressure on the bulk porosity volume fraction, as well as the change in volume and geometry of each individual pore. The evolution of the 3D porosity distribution and mechanical behavior of a sub-volume containing 200 pores was also simulated by finite element analysis. Both experiments and simulations consistently revealed a decrease in the bulk porosity fraction and a bimodal distribution of the individual volume changes after the application of the pressure. This observation is associated with pores containing internal pressure as a result of the HPDC process. Furthermore, a decrease in the complexity factor with increasing volume change is observed experimentally and predicted by simulations. The pressure-treated samples have consistently higher plastic flow strengths.

  7. Comparative experimental and modeling studies of the viscosity behavior of ethanol+C7 hydrocarbon mixtures versus pressure and temperature

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Watson, G.; Baylaucq, A.


    The viscosity of the binary system ethanol+n-heptane has been measured with a falling-body viscometer for seven compositions as well as for the pure compounds in the temperature range 293.15-353.15 K and up to 100 MPa with an experimental uncertainty of +/- 2%. At 0.1 MPa, the viscosity has been...... measured with a classical capillary viscometer (Ubbelohde) with an uncertainty of +/- 1%. A total of 208 experimental datapoints are reported. The viscosity behavior of this binary system is interpreted as the results of changes in the free volume, and the breaking or weakening of hydrogen bonds...... viscosity models with a physical and theoretical background. The evaluated models are based on the hard-sphere scheme, the concepts of the free-volume and the friction theory, and a model derived from molecular dynamics. In addition to these models, the simple compositional models by Grunberg...

  8. Phase behavior for the poly(2-methoxyethyl acrylate)+supercritical solvent+cosolvent mixture and CO{sub 2}+2-methoxyethyl acrylate system at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yoon-Seok; Choi, Yong Seok; Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)


    High pressures phase equilibrium data were presented for the CO{sub 2}+2-MEA system at temperatures ranging from (313.2 to 393.2) K and pressures up to ca. 17.97MPa. The CO{sub 2}+2-MEA system exhibited type-I phase behavior and was modeled using the Peng-Robinson equation of state. The phase behavior data were reported for poly(2-methoxyethyl acrylate) [P(2-MEA)] in supercritical CO{sub 2} and dimethyl ether (DME), as well as for the P(2-MEA)+2-methoxyethyl acrylate (2-MEA) (or DME) in CO{sub 2}. The cloud-point data were measured for the P(2-MEA)+DME in supercritical CO{sub 2} at temperature range of (333-453) K and a pressure range of (8.79-199.14) MPa. The P(2-MEA) in supercritical CO{sub 2} was soluble to 453 K and pressure of 199MPa. The phase behavior for the P(2-MEA)+CO{sub 2}+2-MEA mixture was measured in changes of the pressure-temperature (p, T) slope and with 2-MEA mass fraction of 0.0 wt%, 8.4 wt%, 17.1 wt%, 45.4 wt% and 65.0wt%. With 74.5 wt% 2-MEA to the P(2-MEA)+CO{sub 2} solution, the cloud-point curves took on the appearance of a typical lower critical solution temperature boundary, liquid+liquid transition and liquid+vapor transition. The location of the P(2-MEA)+CO{sub 2} cloud-point curve shifted to lower temperatures and pressures upon the addition of 2-MEA or DME.

  9. Superconductivity under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, K.; Shimizu, K.; Takeda, K.; Tateiwa, N.; Muramatsu, T.; Ishizuka, M.; Kobayashi, T.C


    In part 1, we review techniques developed in our laboratory for producing the complex extreme condition of very low temperature and ultra-high pressure and those for measuring electrical resistance and magnetization of the sample confined in the extremely small space of the used pressure cell. In part 2, we review our experimental results in search for pressure-induced superconductivity, which have been obtained by the use of developed techniques. Typical examples are shown in the case of simple inorganic and organic molecular crystals, ionic crystals, and magnetic metals.

  10. High pressure induced superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, K.; Shimizu, K


    We have developed complex extreme condition of very low temperature down to 30 mK and ultra high pressure exceeding 200 GPa by assembling compact diamond anvil cell (DAC) on a powerful {sup 3}He/{sup 4}He dilution refrigerator. We have also developed measuring techniques of electrical resistance, magnetization and optical measurement for the sample confined in the sample space of the DAC. Using the newly developed apparatus and techniques, we have searched for superconductivity in various materials under pressure. In this paper, we will shortly review our newly developed experimental apparatus and techniques and discuss a few examples of pressure induced superconductivity which were observed recently.

  11. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature (United States)

    Sun, Jianbo; Sun, Chong; Lin, Xueqiang; Cheng, Xiangkun; Liu, Huifeng


    The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH)3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels. PMID:28773328

  12. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Jianbo Sun


    Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.

  13. Investigations into the low temperature behavior of jet fuels: Visualization, modeling, and viscosity studies (United States)

    Atkins, Daniel L.

    Aircraft operation in arctic regions or at high altitudes exposes jet fuel to temperatures below freeze point temperature specifications. Fuel constituents may solidify and remain within tanks or block fuel system components. Military and scientific requirements have been met with costly, low freeze point specialty jet fuels. Commercial airline interest in polar routes and the use of high altitude unmanned aerial vehicles (UAVs) has spurred interest in the effects of low temperatures and low-temperature additives on jet fuel. The solidification of jet fuel due to freezing is not well understood and limited visualization of fuel freezing existed prior to the research presented in this dissertation. Consequently, computational fluid dynamics (CFD) modeling that simulates jet fuel freezing and model validation were incomplete prior to the present work. The ability to simulate jet fuel freezing is a necessary tool for fuel system designers. An additional impediment to the understanding and simulation of jet fuel freezing has been the absence of published low-temperature thermo-physical properties, including viscosity, which the present work addresses. The dissertation is subdivided into three major segments covering visualization, modeling and validation, and viscosity studies. In the first segment samples of jet fuel, JPTS, kerosene, Jet A and Jet A containing additives, were cooled below their freeze point temperatures in a rectangular, optical cell. Images and temperature data recorded during the solidification process provided information on crystal habit, crystallization behavior, and the influence of the buoyancy-driven flow on freezing. N-alkane composition of the samples was determined. The Jet A sample contained the least n-alkane mass. The cooling of JPTS resulted in the least wax formation while the cooling of kerosene yielded the greatest wax formation. The JPTS and kerosene samples exhibited similar crystallization behavior and crystal habits during

  14. High pressure metrology for industrial applications (United States)

    Sabuga, Wladimir; Rabault, Thierry; Wüthrich, Christian; Pražák, Dominik; Chytil, Miroslav; Brouwer, Ludwig; Ahmed, Ahmed D. S.


    To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress–strain analysis of elastic and nonlinear elastic–plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

  15. High pressure photophysics of organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Brey, L. A.


    High pressure spectroscopic studies on several classes of organic compounds were made both in fluid solution (to 10 kbar) and in polymeric media (to 40 kbar). The first three studies were conducted in fluid solution and concern the effect of solvent viscosity on the nonradiative deactivation rates from electronically excited states. Pressure was utilized to attain high viscosities in organic solvents at room temperature. The primary experimental technique used was fluorescence emission spectroscopy. In the fourth and last study observations were made both in fluid solution and in plastic films. The focus of this study was the effect of pressure on the solvent-chromophore dispersion interaction in several polyenes and the concomitant changes in both the radiative and non-radiative rates from the excited states. Extensive use was made of fluorescence lifetime measurements and excitation spectra. 105 references.

  16. Diffusion Creep of Enstatite at High Pressures Under Hydrous Conditions (United States)

    Zhang, Guinan; Mei, Shenghua; Song, Maoshuang; Kohlstedt, David L.


    Mantle convection and large-scale plate motion depend critically on the nature of the lithosphere-asthenosphere boundary and thus on the viscosity structure of Earth's upper mantle, which is determined by the rheological properties of its constituent minerals. To constrain the flow behavior of orthopyroxene, the second most abundant constituent of the upper mantle, deformation experiments were carried out in triaxial compressive creep on fine-grained ( 6 μm) samples of enstatite at high pressures (3.8-6.3 GPa) and high temperatures (1323-1573 K) using a deformation-DIA apparatus. Based on results from this study, the deformation behavior of enstatite is quantitatively presented in the form of a flow law that describes the dependence of deformation rate on differential stress, water fugacity, temperature, and pressure. Specifically, the creep rate depends approximately linearly on stress, indicating deformation in the diffusion creep regime. A least squares regression fit to our data yielded a flow law for diffusion creep with an activation energy of 200 kJ/mol and an activation volume of 14 × 10-6 m3/mol. The magnitude of the water-weakening effect is similar to that for olivine with a water fugacity exponent of r ≈ 0.7. This strong dependence of viscosity on water fugacity (concentration) indicates that the viscosity of an orthopyroxene-bearing mantle varies from one geological setting to another, depending on the large-scale water distribution. Based on the rheology contrast between olivine and enstatite, we conclude that olivine is weaker than enstatite throughout most of the upper mantle except in some shallow regions in the diffusion creep regime.

  17. Power-law electrokinetic behavior as a direct probe of effective surface viscosity (United States)

    Uematsu, Yuki; Netz, Roland R.; Bonthuis, Douwe Jan


    An exact solution to the Poisson-Boltzmann and Stokes equations is derived to describe the electric double layer with inhomogeneous dielectric and viscosity profiles in a lateral electric field. In the limit of strongly charged surfaces and low salinity, the electrokinetic flow magnitude follows a power law as a function of the surface charge density. Remarkably, the power-law exponent is determined by the interfacial dielectric constant and viscosity, the latter of which has eluded experimental determination. Our approach provides a novel method to extract the effective interfacial viscosity from standard electrokinetic experiments. We find good agreement between our theory and experimental data.

  18. High pressure direct injection

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J. [Cummins Westport Inc., Vancouver, BC (Canada)


    A brief overview of Cummins Westport was provided, indicating that Westport originated in the 1980s through a research team at the University of British Columbia, and the hiring of the first employees began in 1996. The joint venture between Cummins and Westport was formed in March 2001. Cummins is the largest builder of commercial diesels in the world, and Westport is a small incubation technology company with emphasis on natural gas. The contribution of each company benefits the joint venture. Cummins brings traditional expertise in product and process development and distribution system, while Westport contributes new high pressure direct injection (HPDI) technology, funding and enthusiasm. The same base engine is kept and only the fuel system is changed. HPDI uses diesel cycle combustion and diesel pilot ignites natural gas. It allows for low emissions, high performance, high efficiency and economic payback. The pilot-ignited HPDI technology was explained, and its application to large class-8 trucks was discussed. The efficiency and performance of diesel engines is maintained by HPDI technology, there are 40 per cent reductions in nitrous oxide emissions, particulate matter emissions are reduced by 60 per cent, and carbon dioxide emissions are reduced by 20 per cent. A field demonstration was reviewed, and the major test at Norcal in San Francisco was discussed. The key success factors were found to be: formalized customer support plan, on-site technical support, parts availability, driver support and interaction, and training. Liquid natural gas fuel contamination was found to cause component wear. The emphasis has now been placed on three issues: injector life improvements, fuel debris and liquid natural gas pump/dome regulator life, and fuel economy improvements. The accomplishments for 2001 were identified, such as rapidly improving reliability, 17 HPDI trucks are upfit and in-service to name a few. The goals for 2002 include the placement of permanent fuel

  19. Thermal behavior of Ni (99.967% and 99.5% purity) deformed to an ultra-high strain by high pressure torsion

    DEFF Research Database (Denmark)

    Zhang, H.W.; Huang, Xiaoxu; Pippan, R.


    Polycrystalline Ni of two purities (99.967% (4N) and 99.5% (2N)) was deformed to an ultra-high strain of εvM = 100 (εvM, von Mises strain) by high pressure torsion at room temperature. The 4N and 2N samples at this strain are nanostructured with an average boundary spacing of 100 nm, a high density...

  20. Odd Viscosity


    Avron, J. E.


    When time reversal is broken the viscosity tensor can have a non vanishing odd part. In two dimensions, and only then, such odd viscosity is compatible with isotropy. Elementary and basic features of odd viscosity are examined by considering solutions of the wave and Navier-Stokes equations for hypothetical fluids where the stress is dominated by odd viscosity.

  1. Melting Point and Viscosity Behavior of High Energy Density Missile Fuels (United States)


    0.996 0.0545 +49.78 0.982 0.03525 20 MOLX HNN & 80 MOL% XTHDCPD TEMP. DENSITY VISCOSITY (DEG C) (G/CMt3) (POISE) -50.25 1.025 0.612 -40.28 1.017 0.3555...80 MOLU HXX & 20 MOLX XTHDCPD TEMP. DENSITY VISCOSITY (DEG C) (G/CMIo) (POISE) -25.00 1.085 1.315 -15.32 1.078 0.675...1.003 0.0411 40 MOLX HXX & 60 MOLX XTHDCPD---------------------------- TEMP. DENSITY VISCOSITY (DEG C) (G/CMI$) (POISE) -55.25 1.056 2.116 -50.30 1.052

  2. Density and viscosity behavior of a North Sea crude oil, natural gas liquid, and their mixtures

    DEFF Research Database (Denmark)

    Schmidt, KAG; Cisneros, Sergio; Kvamme, B


    The friction theory (f-theory) for viscosity modeling, combined with a recently developed characterization procedure, which includes an accurate method to describe the fluid mass distribution, commonly used cubic equations of state, and a Peneloux-type volume translation scheme, have been shown...... to accurately model the saturation pressures, densities, and viscosities of petroleum systems ranging from natural gases to heavy crude oils. The applicability of this overall modeling technique to reproduce measured bubble points, densities, and viscosities of a North Sea crude oil, a natural gas liquid......, and their mixtures has been investigated. The approach has been successfully applied to the modeling of the experimental data of these fluid systems to within an acceptable accuracy....

  3. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 6. High Pressure Research on Materials - Production and Measurement of High Pressures in the Laboratory. P Ch Sahu N V Chandra Shekar. General Article Volume 12 Issue 6 June 2007 pp 10-23 ...

  4. Manipulation of Viscosity Behavior of Wormlike Micellar Gel by Added Perfume Molecular Structure


    Kamada, Miho; Shimizu, Soichiro; Aramaki, Kenji


    We studied the effect of a trace amount of perfumes and oils on the rheological properties of micellar solutions formed in a water/sodium dodecyl sulfate (SDS)/tri(oxyethylene) dodecyl ether (C12EO3) system which gives a maximum zero-shear viscosity as a function of surfactant mixing fraction due to wormlike micelle formation. By adding high-polarity perfumes and oils (9-decen-1-ol, 1-decanol, l-menthol, geraniol and α-terpineol), the viscosity peak shifts to lower hydrophobic surfactant comp...

  5. Hydrogen bond effects on compressional behavior of isotypic minerals: high-pressure polymorphism of cristobalite-like Be(OH)2

    Energy Technology Data Exchange (ETDEWEB)

    Shelton, Hannah; Barkley, Madison C.; Downs, Robert T.; Miletich, Ronald; Dera, Przemyslaw


    Three isotypic crystals, SiO2 (α-cristobalite), ε-Zn(OH)2 (wülfingite), and Be(OH)2 (β-behoite), with topologically identical frameworks of corner-connected tetrahedra, undergo displacive compression-driven phase transitions at similar pressures (1.5–2.0 GPa), but each transition is characterized by a different mechanism resulting in different structural modifications. In this study, we report the crystal structure of the high-pressure γ-phase of beryllium hydroxide and compare it with the high-pressure structures of the other two minerals. In Be(OH)2, the transition from the ambient β-behoite phase with the orthorhombic space group P212121 and ambient unit cell parameters a = 4.5403(4) Å, b = 4.6253(5) Å, c = 7.0599(7) Å, to the high-pressure orthorhombic γ-polymorph with space group Fdd2 and unit cell parameters (at 5.3(1) GPa) a = 5.738(2) Å, b = 6.260(3) Å, c = 7.200(4) Å takes place between 1.7 and 3.6 GPa. This transition is essentially second order, is accompanied by a negligible volume discontinuity, and exhibits both displacive and reversible character. The mechanism of the phase transition results in a change to the hydrogen bond connectivities and rotation of the BeO4 tetrahedra.

  6. Electrokinetic high pressure hydraulic system (United States)

    Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.


    An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

  7. Electrokinetic high pressure hydraulic system (United States)

    Paul, Phillip H.; Rakestraw, David J.


    A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

  8. High pressure neon arc lamp (United States)

    Sze, Robert C.; Bigio, Irving J.


    A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

  9. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    basic types of apparatus that are now being used throughout the world. He was awarded the Nobel Prize in Physics in 1946. The static high pressure generating devices can be divided into two categories: piston-cylinder and opposed anvil devices. These devices with their pressure capabilities are listed in Figure 4.

  10. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink


    In this project high-pressure single crystal X-ray diffraction has been combined with quantitative energy calculations to probe the energy landscape of three hydroquinone clathrates enclosing different guest molecules. The simplicity of the hydroquinone clathrate structures together with their st......In this project high-pressure single crystal X-ray diffraction has been combined with quantitative energy calculations to probe the energy landscape of three hydroquinone clathrates enclosing different guest molecules. The simplicity of the hydroquinone clathrate structures together....... High-pressure crystallography is the perfect method for studying intermolecular interactions, by forcing the molecules closer together. In all three studied hydroquinone clathrates, new pressure induced phase transitions have been discovered using a mixture of pentane and isopentane as the pressure...... transmitting medium. Through careful structural analysis combined with theoretical calculations, the structures of all the new high-pressure phases identified herein were determined. In the hydroquinone - methanol and hydroquinone - acetonitrile clathrate structures the phase transitions break the host...

  11. Critical behavior of 2,6-dimethylpyridine-water: Measurements of specific heat, dynamic light scattering, and shear viscosity

    DEFF Research Database (Denmark)

    Mirzaev, S. Z.; Behrends, R.; Heimburg, Thomas Rainer


    2,6-dimethylpyridine-water, specific heat, dynamic light scattering, shear viscosity Udgivelsesdato: 14 April......2,6-dimethylpyridine-water, specific heat, dynamic light scattering, shear viscosity Udgivelsesdato: 14 April...

  12. Liquid-vapor equilibrium of the systems butylmethylimidazolium nitrate-CO2 and hydroxypropylmethylimidazolium nitrate-CO2 at high pressure: influence of water on the phase behavior. (United States)

    Bermejo, M Dolores; Montero, Marta; Saez, Elisa; Florusse, Louw J; Kotlewska, Aleksandra J; Cocero, M José; van Rantwijk, Fred; Peters, Cor J


    Ionic liquids (IL) are receiving increasing attention due to their potential as "green" solvents, especially when used in combination with SC-CO2. In this work liquid-vapor equilibria of binary mixtures of CO2 with two imidazolium-based ionic liquids (IL) with a nitrate anion have been experimentally determined: butylmethylimidazolium nitrate (BMImNO3) and hydroxypropylmethylimidazolium nitrate (HOPMImNO3), using a Cailletet apparatus that operates according to the synthetic method. CO2 concentrations from 5 up to 30 mol % were investigated. It was found that CO2 is substantially less soluble in HOPMImNO3 than in BMImNO3. Since these ILs are very hygroscopic, water easily can be a major contaminant, causing changes in the phase behavior. In case these Ils are to be used in practical applications, for instance, together with CO2 as a medium in supercritical enzymatic reactions, it is very important to have quantitative information on how the water content will affect the phase behavior. This work presents the first systematic study on the influence of water on the solubility of carbon dioxide in hygroscopic ILs. It was observed that the presence of water reduces the absolute solubility of CO2. However, at fixed ratios of CO2/IL, the bubble point pressure remains almost unchanged with increasing water content. In order to explain the experimental results, the densities of aqueous mixtures of both ILs were determined experimentally and the excess molar volumes calculated.

  13. High-Pressure Lightweight Thrusters (United States)

    Holmes, Richard; McKechnie, Timothy; Shchetkovskiy, Anatoliy; Smirnov, Alexander


    Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems. The performance of current state-ofthe- art liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure. Pump-fed propulsion is suggested for a single-stage bipropellant MAV. Achieving a 90-percent stage propellant fraction is thought to be possible on a 100-kg scale, including sufficient thrust for lifting off Mars. To increase the performance of storable bipropellant rocket engines, a high-pressure, lightweight combustion chamber was designed. Iridium liner electrodeposition was investigated on complex-shaped thrust chamber mandrels. Dense, uniform iridium liners were produced on chamber and cylindrical mandrels. Carbon/carbon composite (C/C) structures were braided over iridium-lined mandrels and densified by chemical vapor infiltration. Niobium deposition was evaluated for forming a metallic attachment flange on the carbon/ carbon structure. The new thrust chamber was designed to exceed state-of-the-art performance, and was manufactured with an 83-percent weight savings. High-performance C/Cs possess a unique set of properties that make them desirable materials for high-temperature structures used in rocket propulsion components, hypersonic vehicles, and aircraft brakes. In particular, more attention is focused on 3D braided C/Cs due to their mesh-work structure. Research on the properties of C/Cs has shown that the strength of composites is strongly affected by the fiber-matrix interfacial bonding, and that weakening

  14. Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites. (United States)

    Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

    The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and

  15. Correlation between non-Fermi-liquid behavior and superconductivity in (Ca, La)(Fe,Co)As2 iron arsenides: A high-pressure study (United States)

    Zhou, W.; Ke, F.; Xu, Xiaofeng; Sankar, R.; Xing, X.; Xu, C. Q.; Jiang, X. F.; Qian, B.; Zhou, N.; Zhang, Y.; Xu, M.; Li, B.; Chen, B.; Shi, Z. X.


    Non-Fermi-liquid (NFL) phenomena associated with correlation effects have been widely observed in the phase diagrams of unconventional superconducting families. Exploration of the correlation between the normal state NFL, regardless of its microscopic origins, and the superconductivity has been argued as a key to unveiling the mystery of the high-Tc pairing mechanism. Here we systematically investigate the pressure-dependent in-plane resistivity (ρ ) and Hall coefficient (RH) of a high-quality 112-type Fe-based superconductor Ca1 -xLaxFe1 -yCoyAs2 (x =0.2 ,y =0.02 ). With increasing pressure, the normal-state resistivity of the studied sample exhibits a pronounced crossover from non-Fermi-liquid to Fermi-liquid behaviors. Accompanied with this crossover, Tc is gradually suppressed. In parallel, the extremum in the Hall coefficient RH(T ) curve, possibly due to anisotropic scattering induced by spin fluctuations, is also gradually suppressed. The symbiosis of NFL and superconductivity implies that these two phenomena are intimately related. Further study on the pressure-dependent upper critical field reveals that the two-band effects are also gradually weakened with increasing pressure and reduced to the one-band Werthamer-Helfand-Hohenberg limit in the low-Tc regime. Overall, our paper supports the picture that NFL, multigap, and extreme RH(T ) are all of the same magnetic origin, i.e., the spin fluctuations in the 112 iron arsenide superconductors.

  16. Exploring the high-pressure behavior of the three known polymorphs of BiPO{sub 4}: Discovery of a new polymorph

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D., E-mail:; García-Domene, B. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Gomis, O. [Centro de Tecnologías Físicas, MALTA Consolider Team, Universitat Politècnica de Valencia, 46022 Valencia (Spain); Santamaría-Perez, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Earth Sciences Department, University College London, London WC1E 6BT (United Kingdom); Muñoz, A.; Rodríguez-Hernández, P. [Departamento de Física, Instituto de Materiales y Nanotecnología, MALTA Consolider Team, Universidad de La Laguna, La Laguna 38205, Tenerife (Spain); Achary, S. N.; Tyagi, A. K. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Popescu, C. [CELLS-ALBA Synchrotron Light Facility, Cerdanyola, 08290 Barcelona (Spain)


    We have studied the structural behavior of bismuth phosphate under compression. We performed x-ray powder diffraction measurements up to 31.5 GPa and ab initio calculations. Experiments were carried out on different polymorphs: trigonal (phase I) and monoclinic (phases II and III). Phases I and III, at low pressure (P < 0.2–0.8 GPa), transform into phase II, which has a monazite-type structure. At room temperature, this polymorph is stable up to 31.5 GPa. Calculations support these findings and predict the occurrence of an additional transition from the monoclinic monazite-type to a tetragonal scheelite-type structure (phase IV). This transition was experimentally found after the simultaneous application of pressure (28 GPa) and temperature (1500 K), suggesting that at room temperature the transition might by hindered by kinetic barriers. Calculations also predict an additional phase transition at 52 GPa, which exceeds the maximum pressure achieved in the experiments. This transition is from phase IV to an orthorhombic barite-type structure (phase V). We also studied the axial and bulk compressibility of BiPO{sub 4}. Room-temperature pressure-volume equations of state are reported. BiPO{sub 4} was found to be more compressible than isomorphic rare-earth phosphates. The discovered phase IV was determined to be the less compressible polymorph of BiPO{sub 4}. On the other hand, the theoretically predicted phase V has a bulk modulus comparable with that of monazite-type BiPO{sub 4}. Finally, the isothermal compressibility tensor for the monazite-type structure is reported at 2.4 GPa showing that the direction of maximum compressibility is in the (0 1 0) plane at approximately 15° (21°) to the a axis for the case of our experimental (theoretical) study.

  17. Carbon nanostructures under high pressure

    CERN Document Server

    Sundqvist, B


    Results from recent high-pressure experiments in the field of fullerenes are briefly reviewed. In particular, new results on one-, two- and three-dimensional polymerized C sub 6 sub 0 and C sub 7 sub 0 are discussed. Results discussed include the first synthesis of a well defined, one-dimensional polymer based on C sub 7 sub 0 , transformations from two-dimensional (2D) to three-dimensional phases in C sub 6 sub 0 , and doping of 2D C sub 6 sub 0 polymers.

  18. Viscosity Solution


    Camilli, Fabio; Prados, Emmanuel


    International audience; Viscosity solution is a notion of weak solution for a class of partial differential equations of Hamilton-Jacobi type. The range of applications of the notions of viscosity solution and Hamilton-Jacobi equations is enormous, including common class of partial differential equations such as evolutive problems and problems with boundary conditions, equations arising in optimal control theory, differential games, second-order equations arising in stochastic optimal control...

  19. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per

    Abstract Background: The research of high pressure (HP) processing of meat based foods needs to address how pressure affects protein interactions, aggregation and/or gelation. The understanding of the gel forming properties of myofibrillar components is fundamental for the development of muscle...... based products (Chapleau et al., 2004;Colmenero, 2002). Object: The aim was to study the rheological properties of pork meat emulsion exposed to HP and the effect of HP on the aggregation state of myofibrillar proteins. To address the role of cathepsin in myofibrillar protein degradation the changes...... in the myofibrillar protein pattern and HP-induced change in activity of cathepsin B and L were investigated. Results: In this study we showed that HP treatment of pork meat emulsion, ranging from 0.1 to 800 MPa, induced protein gel formation as shown by the increased Young’s modulus (Fig.1). Analysis of SDS...

  20. Phase Evolution of Hydrous Enstatite at High Pressures and Temperatures (United States)

    Xu, J.; Zhang, D.; Dera, P.; Zhang, J.; Fan, D.


    Pyroxenes, including Mg-rich orthopyroxene and Ca-rich clinopyroxene, are among the most important minerals in the Earth's upper mantle (account for 20% by volume). Pyroxenes are major phases of harzburgite and lherzolite, which are important components of subducting slabs, so the high pressure behavior of pyroxenes should influence the physical properties of the subducted slabs. Therefore, understanding the phase evolution and thermal equations of state and of pyroxenes at elevated pressure and temperature is crucial to model theupper mantle and subduction zones. On the other hand, water is expected to be incorporated into pyroxene minerals in the upper mantle environments, yet the effect of water on the high pressure behavior of pyroxene has not been fully explored. In this study, we conducted high-pressure single-crystal X-ray diffraction study on hydrous enstatite sample (Mg2Si2O6) at ambient and high temperatures. High-pressure single-crystal diffraction experiments at ambient temperature were performed to 30 GPa at the experimental station 13BMC of the Advanced Photon Source. Two phase transformations were detected within the pressure range. High-pressure and high-temperature single crystal diffraction experiments were conducted to 27 GPa and 700 K also at 13BMC. From the experimental data, we derived the thermoelastic parameters of enstatite and performed structural refinements of enstatite at high pressures and temperatures, which is of implication for understanding of geophysics and geochemistry of subducting slabs.

  1. Combined high-pressure and thermal treatments for processing of tomato puree : evaluation of microbial inactivation and quality parameters

    NARCIS (Netherlands)

    Krebbers, B.; Matser, A.M.; Hoogerwerf, S.W.; Moezelaar, R.; Tomassen, M.M.M.; Berg, van den R.W.


    The effects of combined high-pressure thermal treatments on consistency, viscosity, colour, lycopene content, enzyme activity and micro-organisms were determined, and compared to conventional pasteurisation and sterilisation processes of tomato puree. High-pressure processing at ambient temperature

  2. Polymerization of Formic Acid under High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, A F; Manaa, M R; Zaug, J M; Fried, L E; Montgomery, W B


    We report combined Raman, infrared (IR) and x-ray diffraction (XRD) measurements, along with ab initio calculations on formic acid under pressure up to 50 GPa. Contrary to the report of Allan and Clark (PRL 82, 3464 (1999)), we find an infinite chain low-temperature Pna2{sub 1} structure consisting of trans molecules to be a high-pressure phase at room temperature. Our data indicate the symmetrization and a partially covalent character of the intra-chain hydrogen bonds above approximately 20 GPa. Raman spectra and XRD patterns indicate a loss of the long-range order at pressures above 40 GPa with a large hysteresis at decompression. We attribute this behavior to a three-dimensional polymerization of formic acid.

  3. High-pressure synthesis and magnetic behavior of A-site columnar-ordered double perovskites, LnMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} (Ln = Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Shimura, Gen; Niwa, Ken; Shirako, Yuichi; Hasegawa, Masashi [Department of Crystalline Materials Science, Nagoya University, 464-8601, Nagoya (Japan)


    A-site columnar-ordered double perovskites, LnMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} (Ln = Sm, Gd), were successfully synthesized under high pressure and high temperature (6 GPa, 1375 K). From the synchrotron powder X-ray diffraction patterns, all of the diffraction peaks can be indexed by the P4{sub 2}/nmc space group with lattice parameters a, c ∼ 2a{sub p} (a{sub p}: primitive cubic perovskite lattice) and no ordering of the B-site cations. Rietveld analysis of the synchrotron powder X-ray diffraction patterns and Curie-Weiss fitting of their magnetizations reveal that the ionic formulae of these perovskites are Ln{sup 3+}Mn{sup 2+}(Ga{sup 3+}{sub 0.5}Ti{sup 4+}{sub 0.5}){sub 2}O{sup 2-}{sub 6}. SmMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} shows canted-antiferromagnetic behavior, whereas GdMn(Ga{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 6} exhibits two different magnetic states at low temperature depending on the applied magnetic field and shows an unusual magnetization curve. These magnetic behaviors originate by decreasing the antiferromagnetic interaction by substituting Ga{sup 3+}(d{sup 10}) for Ti{sup 4+}(d{sup 0}) and by decreasing the ferromagnetic interaction between columnar-ordered Ln{sup 3+} and Mn{sup 2+}. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. High-pressure high-temperature rheological studies of colloidal suspensions with carbon nanotube (United States)

    Baby, Anoop; Sadr, Reza; Yarc, Rommel; Amani, Mahmood


    Selection of the drilling fluid, drilling mud, is vital in minimizing the cost and time required for the drilling in oil fields. Drilling mud aids in cooling, lubricating drilling bit, removing the debries from the drill bore and maintaining the wellbore stability. Owing to the enhanced thermo-physical properties and stable nature, suspensions of nanoparticles have been suggested for drilling fluids. High-pressure and high-temperature rheology of a nanomud suspension (nano particles suspended in a mud solution) is studied here. The nanomud is prepared by dispersing a water-based drilling mud suspension (water with 1% Bentonite and 7% Barite particles) with multi-walled carbon nanotubes, MWCNT. The effect of pressure, temperature, and shear rate are independently studied for the various particle loading of the nanoparticles. Viscosity values are measured at a maximum pressure of 170MPa with temperatures ranging from ambient to 180oC. The effect of MWCNT concentration and variation in shear rate are also investigated A shear thinning non-Newtonian behavior is observed for the basemud and the nanomud samples for all cases. The basemud showed an increase in viscosity with an increase in pressure. However, with MWCNT particle addition, this trend is observed to have reversed.

  5. Poly(ethylene-co-vinyl acetate) (EVA) as wax inhibitor of a Brazilian crude oil. Oil viscosity, pour point and phase behavior of organic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Andre L.C.; Lucas, Elizabete F. [Labratorio de Macromoleculas e Coloides na Industria de Petroleo/Instituto de Macromoleculas, Universidade Federal do Rio de Janeiro, P.O. Box 68525, 21945-970 Rio de Janeiro (Brazil); Gonzalez, Gaspar [Petrobras Research Center, Cidade Universitaria, Q.7, RJ 21949-900 Rio de Janeiro (Brazil)


    Several techniques have been used to minimize the problems caused by the wax deposition, and the continuous addition of polymeric inhibitors is considered an attractive technological alternative. The addition of copolymers like polyacrylates, polymethacrylates or poly(ethylene-co-vinyl acetate) (EVA) permit to inhibit the deposition phenomenon; nonetheless, this effect is specific, i.e. similar copolymers present different performance depending on their physical-chemical properties in solution. In this work, the influence of the EVA vinyl acetate content on the viscosity and the pour point of a Brazilian crude oil were evaluated. A correlation between both results was also obtained. The phase behavior and the solubility parameter of EVA copolymers, with different vinyl acetate contents, were investigated in various solvents together with an evaluation of the efficiency of these copolymers as pour point depressants for two different samples of crude oil. EVA copolymers containing 20, 30, 40 and 80 wt.% of vinyl acetate were used and tests with the crude oil were carried out using 50, 500, 1000 and 5000 ppm of EVA as additive. The results obtained from viscosity measurements showed that only below the temperature at which wax crystals start forming did the copolymer exhibit a strong influence in the reduction of oil viscosity, at an optimum concentration. The pour point results revealed EVA 30 to be the most efficient. The results obtained from both experiments showed that the viscosity and the pour point behaviors do not show good correlation. Not only the solubility parameter and the vinyl acetate content, but also the molecular weight and polydispersity have an important influence on both phase behavior and pour point depression. Furthermore, it was confirmed that the additive must present a reduced solubility at a temperature close to the crude oil cloud point. This, however, is not the only factor that determines the efficiency of the additive as paraffin

  6. Studying the melting behavior of coal, biomass, and coal/biomass ash using viscosity and heated stage XRD data

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Folkedahl, B.; Dam-Johansen, Kim


    by the cocombustion tests appeared to be somewhat different compared to that of the laboratory-prepared ash samples. The heated stage XRD data provide useful information regarding the reactions among the various ash compounds and the phase transformations during the heating and cooling of the ash samples and helped...... the explanation of the produced viscosity curves....

  7. Effect of MnO on High-Alumina Slag Viscosity and Corrosion Behavior of Refractory in Slags

    National Research Council Canada - National Science Library

    Xu, Renze; Zhang, Jianliang; Fan, Xiaoyue; Zheng, Weiwei; Zhao, Yongan


    The influence of MnO on viscosities of CaO–SiO2–MgO–Al2O3–Cr2O3-based slags and the corrosion mechanism of carbon composite brick used in blast furnace hearth by slags was investigated in this work...

  8. World of high pressure. Koatsuryoku no sekai

    Energy Technology Data Exchange (ETDEWEB)

    Moritoki, M.; Kanda, T. (Kobe Steel, Ltd., Kobe (Japan))


    The present article describes development and current status of high pressure technology. It introduces applications of high pressure technology to chemical reactions and processings, utilizations of phase changes and supercritical fluids, and applications of high pressure to food processings. Contributions of high pressure technology to synthetic chemistry are mentioned as for industrialization of syntheses of ammonia, urea and methanol, and invention of synthesis of polyethylene. Processing technologies utilizing high pressure are also mentioned as for cold isostatic pressing, hot isostatic pressing, hydrostatic extrusion technique, water jet working technique, and explosive forming technique. Introduced are application of phase changes under high pressure, such as high pressure synthesis of diamond and pressurized crystallization technology, and supercritical extraction technology using water and carbon dioxide. Pressurized food processings of mandarin orange, jam, and grapefruit are described. Furthermore, current status of fundamental technologies of high pressure installations is provided as for pressure vessel technology, pressure generation and control technology, and pressure sealing technology. 12 refs., 15 figs., 1 tab.

  9. High pressure effects on fruits and vegetables

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Matser, A.M.


    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure

  10. Coal swelling and thermoplasticity under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ndaji, F.E.; Butterfield, I.M.; Thomas, K.M. (Newcastle upon Tyne University, Newcastle upon Tyne (United Kingdom). Northern Carbon Research Labs., Dept. of Chemistry)


    The literature on the following topics is reviewed: swelling and agglomeration of coal; measurements of swelling index and dilatometric and plastometric properties at high pressures; and the effects of oxidation, tar addition and minerals on high-pressure thermoplastic properties. 34 refs., 6 figs.

  11. Depth Gauge for Liquids Under High Pressure (United States)

    Zuckerwar, A. J.; Mazel, D. S.


    Piezoelectric element mounted in hole drilled in high-pressure plug. Transducer used to measure depth of liquid when pressure in vessel high. New configuration transmits ultrasonic vibration directly into liquid, enhancing signal strength, accuracy, and range, yet piezoelectric element protected from high-pressure liquid.

  12. Modeling the relationship between the main emulsion components and stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility of orange beverage emulsion using response surface methodology. (United States)

    Mirhosseini, Hamed; Tan, Chin Ping; Hamid, Nazimah Sheikh Abdul; Yusof, Salmah


    The possible relationships between the main emulsion components (namely, Arabic gum, xanthan gum, and orange oil) and the physicochemical properties of orange beverage emulsion were evaluated by using response surface methodology. The physicochemical emulsion property variables considered as response variables were emulsion stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility. The independent variables had the most and least significant ( p turbidity loss rate, viscosity, viscosity ratio, and mobility, respectively. The main effect of Arabic gum was found to be significant ( p turbidity loss rate. The nonlinear regression equations were significantly ( p 0.86), which had no indication of lack of fit. The results indicated that a combined level of 10.78% (w/w) Arabic gum, 0.56% (w/w) xanthan gum, and 15.27% (w/w) orange oil was predicted to provide the overall optimum region in terms of physicochemical properties studied. No significant ( p > 0.05) difference between the experimental and the predicted values confirmed the adequacy of response surface equations.

  13. Application of High Pressure in Food Processing

    Directory of Open Access Journals (Sweden)

    Herceg, Z.


    Full Text Available In high pressure processing, foods are subjected to pressures generally in the range of 100 – 800 (1200 MPa. The processing temperature during pressure treatments can be adjusted from below 0 °C to above 100 °C, with exposure times ranging from a few seconds to 20 minutes and even longer, depending on process conditions. The effects of high pressure are system volume reduction and acceleration of reactions that lead to volume reduction. The main areas of interest regarding high-pressure processing of food include: inactivation of microorganisms, modification of biopolymers, quality retention (especially in terms of flavour and colour, and changes in product functionality. Food components responsible for the nutritive value and sensory properties of food remain unaffected by high pressure. Based on the theoretical background of high-pressure processing and taking into account its advantages and limitations, this paper aims to show its possible application in food processing. The paper gives an outline of the special equipment used in highpressure processing. Typical high pressure equipment in which pressure can be generated either by direct or indirect compression are presented together with three major types of high pressure food processing: the conventional (batch system, semicontinuous and continuous systems. In addition to looking at this technology’s ability to inactivate microorganisms at room temperature, which makes it the ultimate alternative to thermal treatments, this paper also explores its application in dairy, meat, fruit and vegetable processing. Here presented are the effects of high-pressure treatment in milk and dairy processing on the inactivation of microorganisms and the modification of milk protein, which has a major impact on rennet coagulation and curd formation properties of treated milk. The possible application of this treatment in controlling cheese manufacture, ripening and safety is discussed. The opportunities

  14. High-pressure study on some superconductors

    CERN Document Server

    Li, K Q; Yao, Y S; Che, G C; Zhao, Z X


    High-pressure study has played an important role in the investigation of conventional superconductors. Since the discovery of cuprate superconductors, high-pressure study has become even more important, especially as regards high-pressure synthesis and the effect of pressure. In this report, the new materials Ca-doped Pr-123, (Fe, Cu)-1212, and MgB sub 2 - a very new and interesting system synthesized under high pressure with good quality - will be discussed. Chemical inner pressure has been thought to explain the high T sub c of Ca-doped Pr-123. As another possibility, the replacement of the physical pressure effect by a chemical effect will be discussed.

  15. High pressure structural studies of conjugated molecules

    DEFF Research Database (Denmark)

    Knaapila, Matti; Torkkeli, Mika; Scherf, Ullrich


    This chapter highlights high pressure GPa level structural studies of conjugated polymers and their analogues: conjugated oligomers and molecules, and rigid rod polymers. Attention is placed on our recent studies of polyfluorenes.......This chapter highlights high pressure GPa level structural studies of conjugated polymers and their analogues: conjugated oligomers and molecules, and rigid rod polymers. Attention is placed on our recent studies of polyfluorenes....

  16. High-pressure minerals in shocked meteorites (United States)

    Tomioka, Naotaka; Miyahara, Masaaki


    Heavily shocked meteorites contain various types of high-pressure polymorphs of major minerals (olivine, pyroxene, feldspar, and quartz) and accessory minerals (chromite and Ca phosphate). These high-pressure minerals are micron to submicron sized and occur within and in the vicinity of shock-induced melt veins and melt pockets in chondrites and lunar, howardite-eucrite-diogenite (HED), and Martian meteorites. Their occurrence suggests two types of formation mechanisms (1) solid-state high-pressure transformation of the host-rock minerals into monomineralic polycrystalline aggregates, and (2) crystallization of chondritic or monomineralic melts under high pressure. Based on experimentally determined phase relations, their formation pressures are limited to the pressure range up to 25 GPa. Textural, crystallographic, and chemical characteristics of high-pressure minerals provide clues about the impact events of meteorite parent bodies, including their size and mutual collision velocities and about the mineralogy of deep planetary interiors. The aim of this article is to review and summarize the findings on natural high-pressure minerals in shocked meteorites that have been reported over the past 50 years.

  17. High-pressure creep of serpentine, interseismic deformation, and initiation of subduction. (United States)

    Hilairet, Nadege; Reynard, Bruno; Wang, Yanbin; Daniel, Isabelle; Merkel, Sebastien; Nishiyama, Norimasa; Petitgirard, Sylvain


    The supposed low viscosity of serpentine may strongly influence subduction-zone dynamics at all time scales, but until now its role could not be quantified because measurements relevant to intermediate-depth settings were lacking. Deformation experiments on the serpentine antigorite at high pressures and temperatures (1 to 4 gigapascals, 200 degrees to 500 degrees C) showed that the viscosity of serpentine is much lower than that of the major mantle-forming minerals. Regardless of the temperature, low-viscosity serpentinized mantle at the slab surface can localize deformation, impede stress buildup, and limit the downdip propagation of large earthquakes at subduction zones. Antigorite enables viscous relaxation with characteristic times comparable to those of long-term postseismic deformations after large earthquakes and slow earthquakes. Antigorite viscosity is sufficiently low to make serpentinized faults in the oceanic lithosphere a site for subduction initiation.

  18. Pargasite at high pressure and temperature (United States)

    Comboni, Davide; Lotti, Paolo; Gatta, G. Diego; Merlini, Marco; Liermann, Hanns-Peter; Frost, Daniel J.


    The P-T phase stability field, the thermoelastic behavior and the P-induced deformation mechanisms at the atomic scale of pargasite crystals, from the "phlogopite peridotite unit" of the Finero mafic-ultramafic complex (Ivrea-Verbano Formation, Italy), have been investigated by a series of in situ experiments: (a) at high pressure (up to 20.1 GPa), by single-crystal synchrotron X-ray diffraction with a diamond anvil cell, (b) at high temperature (up to 823 K), by powder synchrotron X-ray diffraction using a hot air blower device, and (c) at simultaneous HP-HT conditions, by single-crystal synchrotron X-ray diffraction with a resistive-heated diamond anvil cell (P max = 16.5 GPa, T max = 1200 K). No phase transition has been observed within the P-T range investigated. At ambient T, the refined compressional parameters, calculated by fitting a second-order Birch-Murnaghan Equation of State (BM-EoS), are: V 0 = 915.2(8) Å3 and K P0,T0 = 95(2) GPa (β P0,T0 = 0.0121(2) GPa-1) for the unit-cell volume; a 0 = 9.909(4) Å and K(a) P0,T0 = 76(2) GPa for the a-axis; b 0 = 18.066(7) Å and K(b) P0,T0 = 111(2) GPa for the b-axis; c 0 = 5.299(5) Å and K(c) P0,T0 = 122(12) GPa for the c-axis [K(c) P0,T0 K(b) P0,T0 > K(a) P0,T0]. The high-pressure structure refinements (at ambient T) show a moderate contraction of the TO4 double chain and a decrease of its bending in response to the hydrostatic compression, along with a pronounced compressibility of the A- and M(4)-polyhedra [K P0, T0(A) = 38(2) GPa, K P0, T0(M4) = 79(5) GPa] if compared to the M(1)-, M(2)-, M(3)-octahedra [K P0, T0(M1,2,3) ≤ 120 GPa] and to the rigid tetrahedra [K P0, T0(T1,T2) 300 GPa]. The thermal behavior, at ambient pressure up to 823 K, was modelled with Berman's formalism, which gives: V 0 = 909.1(2) Å3, α0 = 2.7(2)·10-5 K-1 and α1 = 1.4(6)·10-9 K-2 [with α0(a) = 0.47(6)·10-5 K-1, α0(b) = 1.07(4)·10-5 K-1, and α0(c) = 0.97(7)·10-5 K-1]. The petrological implications for the experimental

  19. High pressure processing for food safety. (United States)

    Fonberg-Broczek, Monika; Windyga, B; Szczawiński, J; Szczawińska, M; Pietrzak, D; Prestamo, G


    Food preservation using high pressure is a promising technique in food industry as it offers numerous opportunities for developing new foods with extended shelf-life, high nutritional value and excellent organoleptic characteristics. High pressure is an alternative to thermal processing. The resistance of microorganisms to pressure varies considerably depending on the pressure range applied, temperature and treatment duration, and type of microorganism. Generally, Gram-positive bacteria are more resistant to pressure than Gram-negative bacteria, moulds and yeasts; the most resistant are bacterial spores. The nature of the food is also important, as it may contain substances which protect the microorganism from high pressure. This article presents results of our studies involving the effect of high pressure on survival of some pathogenic bacteria -- Listeria monocytogenes, Aeromonas hydrophila and Enterococcus hirae -- in artificially contaminated cooked ham, ripening hard cheese and fruit juices. The results indicate that in samples of investigated foods the number of these microorganisms decreased proportionally to the pressure used and the duration of treatment, and the effect of these two factors was statistically significant (level of probability, P monocytogenes and A. hydrophila. Mathematical methods were applied, for accurate prediction of the effects of high pressure on microorganisms. The usefulness of high pressure treatment for inactivation of microorganisms and shelf-life extention of meat products was also evaluated. The results obtained show that high pressure treatment extends the shelf-life of cooked pork ham and raw smoked pork loin up to 8 weeks, ensuring good micro-biological and sensory quality of the products.

  20. Fabrication of Bulk Glassy Alloy Foams by High Pressure Hydrogen (United States)

    Wada, Takeshi; Inoue, Akihisa

    Porous Pd42.5Cu30Ni7.5P20 bulk glassy alloy rods with porosities of up to 70% were successfully prepared by high pressure hydrogen of 15 MPa. The melt of Pd42.5Cu30Ni7.5P20 alloy kept under high pressure hydrogen absorbs hydrogen and subsequent water quenching of the melt causes the homogeneous dispersion of hydrogen bubbles, which was resulted from the decrease of hydrogen solubility with decrease of pressure. Annealing the hydrogen bubble containing sample at a supercooled liquid state under vacuum, the bubbles are allowed to expand due to the decrease of viscosity of metallic glass matrix. Pores expansion continues until glassy matrix crystallizes or the equilibration among pressure of the pores, pressure of the atmosphere and surface tension is achieved. By utilizing these phenomena, pores up to 80 m in diameters are homogeneously distributed over the whole cross-sectional area of a fully glassy matrix. Under compressive deformation, the porous alloys with porosities exceeding 40% did not show macroscopic fracture in a wide compressive strain range up to 0.6 whereas the non-porous alloy fractures instantly after elastic limit of about 0.02. Porous bulk glassy alloys exhibit higher plateau stress, lower Young‧s modulus and higher energy absorption capacity compared with the conventional crystalline metal foams.

  1. Viscosity Prediction of Hydrocarbon Mixtures Based on the Friction Theory

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Cisneros, Sergio; Stenby, Erling Halfdan


    The application and capability of the friction theory (f-theory) for viscosity predictions of hydrocarbon fluids is further illustrated by predicting the viscosity of binary and ternary liquid mixtures composed of n-alkanes ranging from n-pentane to n-decane for wide ranges of temperature and from...... low to high pressures. In the f-theory viscosity predictions the SRK and the PRSV EOS have respectively been used. Further, a comparison with the widely used LBC viscosity model shows that better results are obtained with the f-theory models. The obtained AAD% is within or close to the experimental...

  2. Critical Viscosity of Xenon (United States)


    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2001 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure that is placed inside a pressure canister. A similar canister holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (not shown) of the National Institutes of Standards and Technology, Gaithersburg, MD. This is a detail view of MSFC 0100143.

  3. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan


    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  4. High pressure water jet mining machine (United States)

    Barker, Clark R.


    A high pressure water jet mining machine for the longwall mining of coal is described. The machine is generally in the shape of a plowshare and is advanced in the direction in which the coal is cut. The machine has mounted thereon a plurality of nozzle modules each containing a high pressure water jet nozzle disposed to oscillate in a particular plane. The nozzle modules are oriented to cut in vertical and horizontal planes on the leading edge of the machine and the coal so cut is cleaved off by the wedge-shaped body.

  5. High pressure synthesis of bismuth disulfide

    DEFF Research Database (Denmark)

    Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

    In this research the BiS2 compound was synthesized by a high pressure and high temperature method using a multi-anvil large volume press and the structure was solved by single crystal diffraction. The structure contains Bi atoms in distorted square-based pyramidal coordination to five surrounding...

  6. Development of high pressure proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Oddone, P.; Smith, G.; Green, A.; Nemethy, P.; Baksay, L.; Schick, L.; Heflin, E.G.


    We have begun to investigate the possibility of operating gas counters at high pressures. In a first step we were able to operate cylindrical chambers up to 430 atm with a gas gain of about 300 using a mixture of 92% Ar and 8% CH/sub 4/.

  7. High-field/high-pressure ESR. (United States)

    Sakurai, T; Okubo, S; Ohta, H


    We present a historical review of high-pressure ESR systems with emphasis on our recent development of a high-pressure, high-field, multi-frequency ESR system. Until 2000, the X-band system was almost established using a resonator filled with dielectric materials or a combination of the anvil cell and dielectric resonators. Recent developments have shifted from that in the low-frequency region, such as X-band, to that in multi-frequency region. High-pressure, high-field, multi-frequency ESR systems are classified into two types. First are the systems that use a vector network analyzer or a quasi-optical bridge, which have high sensitivity but a limited frequency region; the second are like our system, which has a very broad frequency region covering the THz region, but lower sensitivity. We will demonstrate the usefulness of our high-pressure ESR system, in addition to its experimental limitations. We also discuss the recent progress of our system and future plans. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. High pressure and synchrotron radiation satellite workshop

    Energy Technology Data Exchange (ETDEWEB)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A


    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations.

  9. High-pressure oxidation of methane

    NARCIS (Netherlands)

    Hashemi, Hamid; Christensen, Jakob M.; Gersen, Sander; Levinsky, Howard; Klippenstein, Stephen J.; Glarborg, Peter


    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly

  10. Effect of high-pressure homogenization on different matrices of food supplements. (United States)

    Martínez-Sánchez, Ascensión; Tarazona-Díaz, Martha Patricia; García-González, Antonio; Gómez, Perla A; Aguayo, Encarna


    There is a growing demand for food supplements containing high amounts of vitamins, phenolic compounds and mineral content that provide health benefits. Those functional compounds have different solubility properties, and the maintenance of their compounds and the guarantee of their homogenic properties need the application of novel technologies. The quality of different drinkable functional foods after thermal processing (0.1 MPa) or high-pressure homogenization under two different conditions (80 MPa, 33 ℃ and 120 MPa, 43 ℃) was studied. Physicochemical characteristics and sensory qualities were evaluated throughout the six months of accelerated storage at 40 ℃ and 75% relative humidity (RH). Aroma and color were better maintained in high-pressure homogenization-treated samples than the thermally treated ones, which contributed significantly to extending their shelf life. The small particle size obtained after high-pressure homogenization treatments caused differences in turbidity and viscosity with respect to heat-treated samples. The use of high-pressure homogenization, more specifically, 120 MPa, provided active ingredient homogeneity to ensure uniform content in functional food supplements. Although the effect of high-pressure homogenization can be affected by the food matrix, high-pressure homogenization can be implemented as an alternative to conventional heat treatments in a commercial setting within the functional food supplement or pharmaceutical industry. © The Author(s) 2016.

  11. High-pressure polymorphism of acetylsalicylic acid (aspirin): Raman spectroscopy (United States)

    Crowell, Ethan L.; Dreger, Zbigniew A.; Gupta, Yogendra M.


    Micro-Raman spectroscopy was used to elucidate the high-pressure polymorphic behavior of acetylsalicylic acid (ASA), an important pharmaceutical compound known as aspirin. Using a diamond anvil cell (DAC), single crystals of the two polymorphic phases of aspirin existing at ambient conditions (ASA-I and ASA-II) were compressed to 10 GPa. We found that ASA-I does not transform to ASA-II, but instead transforms to a new phase (ASA-III) above ∼2 GPa. It is demonstrated that this transformation primarily introduces structural changes in the bonding and arrangement of the acetyl groups and is reversible upon the release of pressure. In contrast, a less dense ASA-II shows no transition in the pressure range studied, though it appears to exhibit a disordered structure above 7 GPa. Our results suggest that ASA-III is the most stable polymorph of aspirin at high pressures.

  12. Advanced Diagnostics for High Pressure Spray Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Skeen, Scott A.; Manin, Julien Luc; Pickett, Lyle M.


    The development of accurate predictive engine simulations requires experimental data to both inform and validate the models, but very limited information is presently available about the chemical structure of high pressure spray flames under engine- relevant conditions. Probing such flames for chemical information using non- intrusive optical methods or intrusive sampling techniques, however, is challenging because of the physical and optical harshness of the environment. This work details two new diagnostics that have been developed and deployed to obtain quantitative species concentrations and soot volume fractions from a high-pressure combusting spray. A high-speed, high-pressure sampling system was developed to extract gaseous species (including soot precursor species) from within the flame for offline analysis by time-of-flight mass spectrometry. A high-speed multi-wavelength optical extinction diagnostic was also developed to quantify transient and quasi-steady soot processes. High-pressure sampling and offline characterization of gas-phase species formed following the pre-burn event was accomplished as well as characterization of gas-phase species present in the lift-off region of a high-pressure n-dodecane spray flame. For the initial samples discussed in this work several species were identified, including polycyclic aromatic hydrocarbons (PAH); however, quantitative mole fractions were not determined. Nevertheless, the diagnostic developed here does have this capability. Quantitative, time-resolved measurements of soot extinction were also accomplished and the novel use of multiple incident wavelengths proved valuable toward characterizing changes in soot optical properties within different regions of the spray flame.

  13. High-pressure behavior and equations of state of the cobaltates YBaCo{sub 4}O{sub 7}, YBaCo{sub 4}O{sub 7+{delta}}, YBaCoZn{sub 3}O{sub 7} and BaCoO{sub 3-x}

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Arellano, Erick A., E-mail: [Instituto de Quimica Aplicada, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301 Tuxtepec, Oaxaca (Mexico); Avdeev, Maxim; Yakovlev, Sergey [Bragg Institute, ANSTO, PMB 1, Menai, NSW 2234 (Australia); Lopez-de-la-Torre, Laura; Bayarjargal, Lkhamsuren; Winkler, Bjoern; Friedrich, Alexandra [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Kharton, Vladislav V. [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)


    The compressibilities of the cobaltates YBaCo{sub 4}O{sub 7}, YBaCo{sub 4}O{sub 7+{delta}}, YBaCoZn{sub 3}O{sub 7} and BaCoO{sub 3-x} were investigated by in situ powder X-ray diffraction experiments up to 30 GPa using diamond anvil cells. Pressure-induced phase transitions and amorphization were observed in all the samples. The onset of the pressure-induced phase transition and the onset of the amorphization were observed at {approx}11.7 and 12.2 GPa (YBaCo{sub 4}O{sub 7}), at {approx}14.2 and 16.1 GPa (YBaCo{sub 4}O{sub 7+{delta}}), and at {approx}16.7 and 18.7 GPa (YBaCoZn{sub 3}O{sub 7}), respectively. An attempt to laser anneal at high-pressure failed as it led to a decomposition of the YBaCo{sub 4}O{sub 7} phase into a mixture of phases. Fits of second- and third-order Birch-Murnaghan equations-of-state to the p-V data result in B{sub 0}=109(3) GPa for YBaCo{sub 4}O{sub 7}; B{sub 0}=186(4) GPa and B Prime =1.5 for YBaCo{sub 4}O{sub 7+{delta}}; and B{sub 0}=117(1) GPa for YBaCoZn{sub 3}O{sub 7}. The high-pressure behavior of the studied compounds was compared with isostructural compounds and it is shown that the oxygen-content has a very large effect on the high-pressure behavior of this class of materials. Highlights: Black-Right-Pointing-Pointer Compressibilities were investigated by in situ DAC powder X-ray diffraction experiments. Black-Right-Pointing-Pointer Pressure-induced phase transitions were observed in all the samples. Black-Right-Pointing-Pointer High-pressure phases were very sensitive to small amounts of stresses and strains. Black-Right-Pointing-Pointer Due to the metastability of the compounds, laser annealing leads to decomposition. Black-Right-Pointing-Pointer Oxygen-content has a very large effect on the high pressure behavior in these materials.

  14. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)


    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  15. Thermal analysis of high pressure micro plasma discharge (United States)

    Mobli, Mostafa

    High pressure micro plasma discharge has been at the center of interest in recent years, because of their vast applications, ease of access and cost efficiency. This attributes to atmospheric discharges that are generated in ambient conditions and therefore can be readily applicable to everyday use. The absence of vacuum makes these high pressure discharges to be inexpensive to operate. Despite the ease of operation, the high pressure is a source of enhanced gas heating as the gas temperature cannot be controlled by diffusion alone. Gas heating is therefore an important factor when it comes to the simulation of high pressure micro plasma discharge, unlike their low pressure counterpart where the heat generation is almost negligible. Low pressure discharge due to their low degree of collisionality generates ionic species and electrons at small concentrations, whereas high pressure discharge due to their higher gas density produces ions and electrons at higher concentrations which is a direct consequence of increase collision. The higher gas density and consequential large concentration of ionic species and electron contributes directly to higher heat generation rates. . In this thesis the gas temperature transport of high pressure micro plasma discharge has been studied with a special focus on the heat source terms, temperature boundary conditions, temperature distribution in the solid phase electrodes and the gas phase and their overall influence on the plasma characteristics. For this purpose a multi-physics mathematical model has been developed that comprised of a plasma module, neutral gas temperature module, external circuit module and conjugate heat transfer module. The plasma module consisted of conservation of the different ionic, electronically excited species, radicals, neutrals and electrons, conservation of the electron temperature, and electric field. The external circuit module resolved the coupled driving circuit comprised of a voltage source, ballast

  16. Cementing liners through deep high pressure ones

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, B.J.; Barrios, J.R.


    Entry of gas into the liner-hole annulus during and after cementing liners though deep high pressure zones, generally results in a gas cut cement column from depth of gas entry to top of liner. Prior to undertaking design of liner cementation, it is necessary to know fracture pressure limits of the formations. It is also necessary to know the formation pore pressure or the pressure required to hold gas in the formation and precisely the depth of formation from which gas emerges. This knowledge may be gained from a study of formation pressure gradients of nearby wells or from sonic log analysis of the interval being readied for cementation. Both single-stage and 2-stage techniques are used to solve liner cementing problems in these high pressure zones. An example sets out conditions which are more or less typical and demonstrates how the problem may be considered and solved.

  17. Inspection technology for high pressure pipes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae H.; Lee, Jae C.; Eum, Heung S.; Choi, Yu R.; Moon, Soon S.; Jang, Jong H


    Various kinds of defects are likely to be occurred in the welds of high pressure pipes in nuclear power plants. Considering the recent accident of Zuruga nuclear power plant in Japan, reasonable policy is strongly requested for the high pressure pipe integrity. In this study, we developed the technologies to inspect pipe welds automatically. After development of scanning robot prototype in the first research year, we developed and implemented the algorithm of automatic tracking of the scanning robot along the weld line of the pipes. We use laser slit beam on weld area and capture the image using digital camera. Through processing of the captures image, we finally determine the weld line automatically. In addition, we investigated a new technology on micro systems for developing micro scanning robotic inspection of the pipe welds. The technology developed in this study is being transferred to the industry. (author)

  18. High-pressure oxidation of methane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Gersen, Sander


    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly...... diluted in nitrogen. It was found that under the investigated conditions, the onset temperature for methane oxidation ranged from 723 K under reducing conditions to 750 K under stoichiometric and oxidizing conditions. The RCM experiments were carried out at pressures of 15–80 bar and temperatures of 800......–1250 K under stoichiometric and fuel-lean (Φ=0.5) conditions. Ignition delays, in the range of 1–100 ms, decreased monotonically with increasing pressure and temperature. A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry...

  19. Inelastic neutron scattering to very high pressures (United States)

    Klotz, S.; Braden, M.; Besson, J. M.


    Progress in high-pressure and neutron scattering methods has recently allowed measurements of phonon dispersion curves of simple solids at high pressures to 10 GPa. In this technique single crystals of 10 25 mm3 volume are compressed by the Paris-Edinburgh cell and the phonon frequencies are measured on high-flux triple axis spectrometers. Detailed studies of the lattice dynamics of low-compressible systems are feasible, including measurements of mode Grüneisen parameters, elastic constants, and precursor effects of phase transitions. We describe the experimental set-up and illustrate its potential by results on semiconductors (Ge and GaSb) and metals (Fe and Zn) obtained at the LLB (Saclay) and ILL (Grenoble) reactor sources.

  20. Melting point of polymers under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Andreas [Technische Universitaet Darmstadt, Ernst Berl-Institut fuer Technische und Makromolekulare Chemie, Petersenstr. 20, D-64287 Darmstadt (Germany)], E-mail:; Freitag, Detlef [Friedrich-Alexander-Universitaet, Erlangen-Nuernberg (Germany); Freidel, Frank [Technische Universitaet Darmstadt, Ernst Berl-Institut fuer Technische und Makromolekulare Chemie, Petersenstr. 20, D-64287 Darmstadt (Germany); Luft, Gerhard [Technische Universitaet Darmstadt, Ernst Berl-Institut fuer Technische und Makromolekulare Chemie, Petersenstr. 20, D-64287 Darmstadt (Germany)], E-mail:


    The influence of highly compressed gases on the melting of polyethylene was investigated for nitrogen, helium and ethylene. The impact of the particle size of the polymer and the heating rate on the melting point were also analysed. The melting points were determined with a high pressure differential thermal analysis (HPDTA) apparatus. These measurements were compared with independent measurements, done by high pressure differential scanning calorimetry (HPDSC), without gas. From this experimental data it was possible to calculate the concentration of the gas in the molten polymer phase based on equilibrium thermodynamics. For high density polyethylene (HDPE), a concentration of nitrogen at the polymer melting point of 10.4-35.7 mL(SATP) g(polymer){sup -1}, in the pressure interval of 65-315 MPa, was calculated.

  1. Stability of xenon oxides at high pressures. (United States)

    Zhu, Qiang; Jung, Daniel Y; Oganov, Artem R; Glass, Colin W; Gatti, Carlo; Lyakhov, Andriy O


    Xenon, which is quite inert under ambient conditions, may become reactive under pressure. The possibility of the formation of stable xenon oxides and silicates in the interior of the Earth could explain the atmospheric missing xenon paradox. Using an ab initio evolutionary algorithm, we predict the existence of thermodynamically stable Xe-O compounds at high pressures (XeO, XeO(2) and XeO(3) become stable at pressures above 83, 102 and 114 GPa, respectively). Our calculations indicate large charge transfer in these oxides, suggesting that large electronegativity difference and high pressure are the key factors favouring the formation of xenon compounds. However, xenon compounds cannot exist in the Earth's mantle: xenon oxides are unstable in equilibrium with the metallic iron occurring in the lower mantle, and xenon silicates are predicted to decompose spontaneously at all mantle pressures (xenon atoms may be retained at defects in mantle silicates and oxides.

  2. High pressure layered structure of carbon disulfide


    Naghavi, S. Shahab; Crespo, Yanier; Martonak, Roman; Tosatti, Erio


    Solid CS$_{2}$ is superficially similar to CO$_{2}$, with the same $Cmca$ molecular crystal structure at low pressures, which has suggested similar phases also at high pressures. We carried out an extensive first principles evolutionary search in order to identify the zero temperature lowest enthalpy structures of CS$_{2}$ for increasing pressure up to 200\\,GPa. Surprisingly, the molecular $Cmca$ phase does not evolve into $\\beta$-cristobalite as in CO$_{2}$, but transforms instead into phase...

  3. High Pressure Multicomponent Adsorption in Porous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan


    We analyse adsorption of a multicomponent mixture at high pressure on the basis of the potential theory of adsorption. The adsorbate is considered as a segregated mixture in the external field produced by a solid adsorbent. we derive an analytical equation for the thickness of a multicomponent film...... close to a dew point. This equation (asymptotic adsorption equation, AAE) is a first order approximation with regard to the distance from a phase envelope....

  4. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

    Abstract. NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si. NMR signals arising from the antiferromagnetic (AF) region besides the previously observed 29Si. NMR signals which come ...

  5. CRRT Connected to ECMO: Managing High Pressures. (United States)

    de Tymowski, Christian; Augustin, Pascal; Houissa, Hamda; Allou, Nicolas; Montravers, Philippe; Delzongle, Alienor; Pellenc, Quentin; Desmard, Mathieu

    Metabolic disorders and fluid overload are indications of continuous renal replacement therapy (CRRT) including continuous venovenous hemofiltration in patients on extracorporeal membrane oxygenation (ECMO). Direct connection of CRRT machine to the ECMO circuit provides many advantages. Nevertheless, because pressures in CRRT lines relate to ECMO blood flow, high ECMO blood flow may be associated with high pressures in CRRT lines. Thus, management of CRRT pressure lines becomes challenging. We evaluated a protocol for managing high CRRT pressures. Connections were performed according to a standardized protocol to maintain CRRT lines in the correct pressure ranges without modifying ECMO settings or inhibiting pressure alarms. To achieve this goal, the way of connecting of CRRT lines was adapted following a standardized protocol. Connection was first attempted between pump and oxygenator in the 12 patients. In five cases, high pressures in CRRT lines were successfully managed by changing the connection segment. Continuous renal replacement therapy parameters were within target levels and reduction of serum creatinine was 37%. In conclusion, management of high pressures in CRRT lines induced by ECMO could be achieved without modifying ECMO blood flow or inhibiting CRRT alarms. Iterative stops were avoided allowing efficient procedures.

  6. Path Dependency of High Pressure Phase Transformations (United States)

    Cerreta, Ellen


    At high pressures titanium and zirconium are known to undergo a phase transformation from the hexagonal close packed (HCP), alpha-phase to the simple-hexagonal, omega-phase. Under conditions of shock loading, the high-pressure omega-phase can be retained upon release. It has been shown that temperature, peak shock stress, and texture can influence the transformation. Moreover, under these same loading conditions, plastic processes of slip and twinning are also affected by similar differences in the loading path. To understand this path dependency, in-situ velocimetry measurements along with post-mortem metallographic and neutron diffraction characterization of soft recovered specimens have been utilized to qualitatively understand the kinetics of transformation, quantify volume fraction of retained omega-phase and characterize the shocked alpha and omega-phases. Together the work described here can be utilized to map the non-equilibrium phase diagram for these metals and lend insight into the partitioning of plastic processes between phases during high pressure transformation. In collaboration with: Frank Addesssio, Curt Bronkhorst, Donald Brown, David Jones, Turab Lookman, Benjamin Morrow, Carl Trujillo, Los Alamos National Lab.; Juan Pablo Escobedo-Diaz, University of New South Wales; Paulo Rigg, Washington State University.

  7. High pressure synthesis gas conversion. Final report

    Energy Technology Data Exchange (ETDEWEB)


    The purpose of this research project is to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by Clostridium ljungdahlii. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors. A maximum operating pressure of 150 psig has been shown to be possible for C. ljungdahlli with the medium of Phillips et al. This medium was developed for atmospheric pressure operation in the CSTR to yield maximum ethanol concentrations and thus is not best for operation at elevated pressures. It is recommended that a medium development study be performed for C. ljungdahlii at increased pressure. Cell concentration, gas conversion and product concentration profiles were presented for C. ljungdahlii as a function of gas flow rate, the variable which affects bacterium performance the most. This pressure was chosen as a representative pressure over the 0--150 psig operating pressure range for the bacterium. Increased pressure negatively affected ethanol productivity probably due to the fact that medium composition was designed for atmospheric pressure operation. Medium development at increased pressure is necessary for high pressure development of the system.

  8. High pressure CO hydrogenation over bimetallic Pt-Co catalysts

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Medford, Andrew James; Studt, Felix


    The potential of bimetallic Pt-Co catalysts for production of higher alcohols in high pressure CO hydrogenation has been assessed. Two catalysts (Pt3Co/SiO2 and PtCo/SiO2) were tested, and the existing literature on CO hydrogenation over Pt-Co catalysts was reviewed. It is found that the catalysts...... produce mainly methanol in the Pt-rich composition range andmainly hydrocarbons (and to a modest extent higher alcohols) in the Co-rich composition range. The transition between the two types of behavior occurs in a narrow composition range around a molar Pt:Co ratio of 1:1....

  9. High Pressure and Temperature Effects on the Viscosity, Density, and Bulk Modulus of Four Liquid Lubricants. (United States)


    T Y Ct ., A ’ .’. I r ICA T I t > N Or T~ e I ’ P A r t (Ilk. ... ..~~.. l’nter. ,l) REPORT DOCU,~%ENTAT ION PAGE F .) ~~~~PORT N ~~~~‘,,.,__,. 2...I O N NAME AND A D D R E S S 10. P R O G R A M E L E M E,~l T , PROJ E CT TA S, ( M i d w e s t Research I n s t i t u t e A R E A S W O R K / P...the same time, The coil for tap water is used pr imar ily to hasten cooling of the bath. The bath liquid temperature is measured by ASTM extended—range

  10. Comparative study on the high pressure inactivation behavior of the Shiga toxin-producing Escherichia coli O104:H4 and O157:H7 outbreak strains and a non-pathogenic surrogate. (United States)

    Reineke, Kai; Sevenich, Robert; Hertwig, Christian; Janßen, Traute; Fröhling, Antje; Knorr, Dietrich; Wieler, Lothar H; Schlüter, Oliver


    Enterohemorrhagic Escherichia coli strains cause each year thousands of illnesses, which are sometimes accompanied by the hemolytic uremic syndrome, like in the 2011 outbreak in Germany. For preservation thermal pasteurization is commonly used, which can cause unwanted quality changes. To prevent this high pressure treatment is a potential alternative. Within this study, the 2011 outbreak strain O104:H4, an O157:H7 and a non-pathogenic strain (DSM1116) were tested. The cells were treated in buffer (pH 7 and pH 5) and carrot juice (pH 5.1) in a pressure temperature range of 0.1-500 MPa and 20-70 °C. Flow cytometry was used to investigate the pressure impact on cell structures of the strain DSM1116. Both pathogenic strains had a much higher resistance in buffer and carrot juice than the non-pathogenic surrogate. Further, strains cultivated and treated at a lower pH-value showed higher pressure stability, presumably due to variations in the membrane composition. This was confirmed for the strain DSM1116 by flow cytometry. Cells cultivated and treated at pH 5 had a stronger ability to retain their membrane potential but showed higher rates of membrane permeabilization at pressures <200 MPa compared to cells cultivated and treated at pH 7. These cells had the lowest membrane permeabilization rate at around 125 MPa, possibly denoting that variations in the fatty acid composition and membrane fluidity contribute to this stabilization phenomenon. Copyright © 2014 Elsevier Ltd. All rights reserved.


    Energy Technology Data Exchange (ETDEWEB)

    Stefano Orsino


    As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical

  12. Heterogeneous flow during high-pressure torsion

    Directory of Open Access Journals (Sweden)

    Roberto B. Figueiredo


    Full Text Available High-Pressure Torsion (HPT has attracted significant attention in recent years as an effective technique to process ultrafine and nanostructured materials. The hydrostatic pressure developed during processing prevents the occurrence of cracks and the low thickness to diameter ratio provides the opportunity for developing high strains at low numbers of rotations. The present work analyses the plastic flow during HPT. Experimental results and computer modeling are used to describe heterogeneous plastic flow. It is shown that variations in structure, hardness and in the distribution of strain are observed along the disc thickness. The sources of these heterogeneities are discussed.

  13. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...

  14. High pressure hydroformylation in the chemical industry

    Energy Technology Data Exchange (ETDEWEB)

    Paciello, R. [BASF Aktiengesellschaft, Ludwigshafen (Germany)


    Higher oxo alcohols are intermediates for large-scale applications, such as plasticizers, detergents and fuel additives, as well as being useful in the synthesis of fine chemicals such as vitamins or flavors and fragrances. Many of these alcohols are still made using high pressure technologies. Advantages and disadvantages of different technologies presently in use or being developed are discussed. In particular, efforts to decrease raw material costs, e.g. by increasing yield, or investment, e.g. by decreasing pressure, will be highlighted. (orig.)

  15. Transport properties of liquid metal hydrogen under high pressures (United States)

    Brown, R. C.; March, N. H.


    A theory is developed for the compressibility and transport properties of liquid metallic hydrogen, near to its melting point and under high pressure. The interionic force law is assumed to be of the screened Coulomb type, because hydrogen has no core electrons. The random phase approximation is used to obtain the structure factor S(k) of the system in terms of the Fourier transform of this force law. The long wavelenth limit of the structure factor S(o) is related to the compressibility, which is much lower than that of alkali metals at their melting points. The diffusion constant at the melting point is obtained in terms of the Debye frequency, using a frequency spectrum analogous with the phonon spectrum of a solid. A similar argument is used to obtain the combined shear and bulk viscosities, but these depend also on S(o). The transport coefficients are found to be about the same size as those of alkali metals at their melting points.

  16. High-pressure differential scanning calorimetry of colorant products. (United States)

    Marsh, J M; Clarke, C J; Meinert, K; Dahlgren, R M


    High-pressure differential scanning calorimetry (HPDSC) can be used to gain information on both the degree of crystallinity in the intermediate filaments (IFs) and the structural rigidity of the surrounding matrix or intermediate filament associated proteins (IFAP) of the hair cortex (1-3). We have used HPDSC to measure changes in the denaturation temperature (T(D)) and enthalpy (DeltaH(D)) of the crystalline components after multiple treatments with permanent hair colorant products. We have observed that after three repeat treatments both the denaturation enthalpy and peak temperature are significantly decreased vs the untreated starting substrate. However, on dialysis of the fibers in deionized water this decrease is shown to be completely reversible, returning the enthalpy and temperature to that of the untreated hair. It is proposed that the decrease is due to the incorporation of formulation components such as the alkalizer and surfactants etc. and metal ions such as calcium and magnesium from the tap wash water. These components are predicted to have a non-permanent effect on the salt bridges and hydrogen bonds and hence the rigidity or viscosity of the matrix. We have compared the denaturation temperature with the tensile properties of the fiber after treatment both before and after removal of actives from the fiber.

  17. Effect of high pressure treatment on liquid whole egg (United States)

    Németh, Csaba; Dalmadi, István; Mráz, Balázs; Friedrich, László; Zeke, Ildikó; Juhász, Réka; Suhajda, Ágnes; Balla, Csaba


    In our tests, we artificially infected liquid whole egg samples with Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus bacteria, and then treated the samples in "Food Lab900" high hydrostatic pressure (HHP) instrument for 3-17 min at 200-400 MPa. Subsequently, the change of the viable cell count of the specific bacteria has been tested. In addition to the samples infected with various bacteria, non-infected samples were also treated in each test and the change in viable cell count, colour and viscosity of the samples upon the effect of the treatment. In summary, it can be concluded that in each test of our investigations, the viable cell count of S. enteritidis critical for egg products is reduced significantly, while the reduction of the total viable cell count was around two magnitudes. Additionally, based on our results, microbial destruction, reduction of enthalpy (denaturation of egg white) caused by the treatment at HPP, and colour change are primarily affected by the pressure level, while the changes in rheological properties are also significantly affected by the duration of high pressure treatment (p<0.05).

  18. High Pressure and Temperature Effects in Polymers (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  19. High Pressure Hydrogen from First Principles (United States)

    Morales, M. A.


    Typical approximations employed in first-principles simulations of high-pressure hydrogen involve the neglect of nuclear quantum effects (NQE) and the approximate treatment of electronic exchange and correlation, typically through a density functional theory (DFT) formulation. In this talk I'll present a detailed analysis of the influence of these approximations on the phase diagram of high-pressure hydrogen, with the goal of identifying the predictive capabilities of current methods and, at the same time, making accurate predictions in this important regime. We use a path integral formulation combined with density functional theory, which allows us to incorporate NQEs in a direct and controllable way. In addition, we use state-of-the-art quantum Monte Carlo calculations to benchmark the accuracy of more approximate mean-field electronic structure calculations based on DFT, and we use GW and hybrid DFT to calculate the optical properties of the solid and liquid phases near metallization. We present accurate predictions of the metal-insulator transition on the solid, including structural and optical properties of the molecular phase. This work was supported by the U.S. Department of Energy at the Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and by LDRD Grant No. 13-LW-004.

  20. Is sodium a superconductor under high pressure? (United States)

    Tutchton, Roxanne; Chen, Xiaojia; Wu, Zhigang


    Superconductivity has been predicted or measured for most alkali metals under high pressure, but the computed critical temperature (T c ) of sodium (Na) at the face-centered cubic (fcc) phase is vanishingly low. Here we report a thorough, first-principles investigation of superconductivity in Na under pressures up to 260 GPa, where the metal-to-insulator transition occurs. Linear-response calculations and density functional perturbation theory were employed to evaluate phonon distributions and the electron-phonon coupling for bcc, fcc, cI16, and tI19 Na. Our results indicate that the maximum electron-phonon coupling parameter, λ, is 0.5 for the cI16 phase, corresponding to a theoretical peak in the critical temperature at T c ≈1.2 K. When pressure decreases or increases from 130 GPa, T c drops quickly. This is mainly due to the lack of p-d hybridization in Na even at 260 GPa. Since current methods based on the Eliashberg and McMillian formalisms tend to overestimate the T c (especially the peak values) of alkali metals, we conclude that under high pressure-before the metal-to-insulator transition at 260 GPa-superconductivity in Na is very weak, if it is measurable at all.

  1. New developments in high pressure x-ray spectroscopy beamline at High Pressure Collaborative Access Team. (United States)

    Xiao, Y M; Chow, P; Boman, G; Bai, L G; Rod, E; Bommannavar, A; Kenney-Benson, C; Sinogeikin, S; Shen, G Y


    The 16 ID-D (Insertion Device - D station) beamline of the High Pressure Collaborative Access Team at the Advanced Photon Source is dedicated to high pressure research using X-ray spectroscopy techniques typically integrated with diamond anvil cells. The beamline provides X-rays of 4.5-37 keV, and current available techniques include X-ray emission spectroscopy, inelastic X-ray scattering, and nuclear resonant scattering. The recent developments include a canted undulator upgrade, 17-element analyzer array for inelastic X-ray scattering, and an emission spectrometer using a polycapillary half-lens. Recent development projects and future prospects are also discussed.

  2. High Pressure Behavior of Hydrocarbons. Joule-Thomson Expansion of Gas Condensates Comportement des hydrocarbures à haute pression. Détente de Joule-Thomson de gaz à condensats

    Directory of Open Access Journals (Sweden)

    Kortekaas W. G.


    Full Text Available This paper presents calculations of Joule-Thomson inversion effects in high-pressure-high-temperature gas condensates. Isenthalpic expansions were modeled for several gas condensate mixtures reported in literature using the Soave-Redlich-Kwong and the Peng-Robinson equations of state. The calculations confirmed qualitatively the heating of gas condensates at expansion. Although reservoir temperatures are in the region where cooling occurs, i. e. , inside the inversion curve, it was shown that reservoir pressures lie outside this region, and that the temperature will increase until the inversion curve is reached. The calculated temperature increases are not very large. Although exact values depend on fluid composition, reservoir conditions, and pressure drop, typical calculated temperature increases are in the range of 10-30°C for reservoir pressures of 1000 bar. A sensitivity study showed that both reservoir pressure and fluid composition greatly affect the temperature increase. With increasing pressures and increasing amounts of heavy constituents present in gas condensate mixtures, the maximum possible temperature effect will also increase. Unfortunately, due to lack of experimental information, the reliability of the calculated results could not be verified. Cet article présente des calculs de l'effet d'inversion de Joule-Thomson pour des gaz à condensats à haute température et haute pression. La détente isenthalpique a été modélisée pour plusieurs compositions de gaz à condensats trouvées dans la littérature, en utilisant les équations d'état de Soave-Redlich-Kwong et de Peng-Robinson. Ces calculs confirment qualitativement le réchauffement des gaz à condensat lors de la détente. Bien que les températures de gisement se trouvent dans la région où un refroidissement s'observe, c'est-à-dire à l'intérieur de la courbe d'inversion, on a montré que les pressions de gisement correspondent à l'extérieur de cette r

  3. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita


    highlighted by high pressure optical spectroscopy whilst analogous x-ray diffraction experiments remain less frequent. By focusing on a class of blue-emitting π-conjugated polymers, polyfluorenes, this article reviews optical spectroscopic studies under hydrostatic pressure, addressing the impact of molecular......This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure...... and intermolecular self-organization that typically determine transport and optical emission in π-conjugated oligomers and polymers. In this context, hydrostatic pressure through diamond anvil cells has proven to be an elegant tool to control structure and interactions without chemical intervention. This has been...

  4. High pressure chemistry of substituted acetylenes

    Energy Technology Data Exchange (ETDEWEB)

    Chellappa, Raja [Los Alamos National Laboratory; Dattelbaum, Dana [Los Alamos National Laboratory; Sheffield, Stephen [Los Alamos National Laboratory; Robbins, David [Los Alamos National Laboratory


    High pressure in situ synchrotron x-ray diffraction experiments were performed on substituted polyacetylenes: tert-butyl acetylene [TBA: (CH{sub 3}){sub 3}-C{triple_bond}CH] and ethynyl trimethylsilane [ETMS: (CH{sub 3}){sub 3}-Si{triple_bond}CH] to investigate pressure-induced chemical reactions. The starting samples were the low temperature crystalline phases which persisted metastably at room temperature and polymerized beyond 11 GPa and 26 GPa for TBA and ETMS respectively. These reaction onset pressures are considerably higher than what we observed in the shockwave studies (6.1 GPa for TBA and 6.6 GPa for ETMS). Interestingly, in the case of ETMS, it was observed with fluid ETMS as starting sample, reacts to form a semi-crystalline polymer (crystalline domains corresponding to the low-T phase) at pressures less than {approx}2 GPa. Further characterization using vibrational spectroscopy is in progress.

  5. Superconductivity from magnetic elements under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Katsuya [KYOKUGEN, Research Center for Materials Science at Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)]. E-mail:; Amaya, Kiichi [Toyota Physical and Chemical Research Institute, Aichi 480-1192 (Japan); Suzuki, Naoshi [Graduate School of Engineering Science, Osaka University, Osaka 560-8531 (Japan); Onuki, Yoshichika [Graduate School of Science, Osaka University, Osaka 560-0043 (Japan)


    Can we expect the appearance of superconductivity from magnetic elements? In general, superconductivity occurs in nonmagnetic metal at low temperature and magnetic impurities destroy superconductivity; magnetism and superconductivity are as incompatible as oil and water. Here, we present our experimental example of superconducting elements, iron and oxygen. They are magnetic at ambient pressure, however, they become nonmagnetic under high pressure, then superconductor at low temperature. What is the driving force of the superconductivity? Our understanding in the early stages was a simple scenario that the superconductive state was obtained as a consequence of an emergence of the nonmagnetic states. In both cases, we may consider another scenario for the appearance of superconductivity; the magnetic fluctuation mechanism in the same way as unconventional superconductors.

  6. High pressure Raman scattering of silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Khachadorian, Sevak; Scheel, Harald; Thomsen, Christian [Institut fuer Festkoerperphysik, Technische Universitaet Berlin, 10623 Berlin (Germany); Papagelis, Konstantinos [Materials Science Department, University of Patras, 26504 Patras (Greece); Colli, Alan [Nokia Research Centre, 21 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Ferrari, Andrea C, E-mail: [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)


    We study the high pressure response, up to 8 GPa, of silicon nanowires (SiNWs) with {approx} 15 nm diameter, by Raman spectroscopy. The first order Raman peak shows a superlinear trend, more pronounced compared to bulk Si. Combining transmission electron microscopy and Raman measurements we estimate the SiNWs' bulk modulus and the Grueneisen parameters. We detect an increase of Raman linewidth at {approx} 4 GPa, and assign it to pressure induced activation of a decay process into LO and TA phonons. This pressure is smaller compared to the {approx} 7 GPa reported for bulk Si. We do not observe evidence of phase transitions, such as discontinuities or change in the pressure slopes, in the investigated pressure range.

  7. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail:; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)


    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  8. High-pressure structures of methane hydrate

    CERN Document Server

    Hirai, H; Fujihisa, H; Sakashita, M; Katoh, E; Aoki, K; Yamamoto, Y; Nagashima, K; Yagi, T


    Three high-pressure structures of methane hydrate, a hexagonal structure (str. A) and two orthorhombic structures (str. B and str. C), were found by in situ x-ray diffractometry and Raman spectroscopy. The well-known structure I (str. I) decomposed into str. A and fluid at 0.8 GPa. Str. A transformed into str. B at 1.6 GPa, and str. B further transformed into str. C at 2.1 GPa which survived above 7.8 GPa. The fluid solidified as ice VI at 1.4 GPa, and the ice VI transformed to ice VII at 2.1 GPa. The bulk moduli, K sub 0 , for str. I, str. A, and str. C were calculated to be 7.4, 9.8, and 25.0 GPa, respectively.

  9. Novel High Pressure Pump-on-a-Chip Technology Project (United States)

    National Aeronautics and Space Administration — HJ Science & Technology, Inc. proposes to develop a novel high pressure "pump-on-a-chip" (HPPOC) technology capable of generating high pressure and flow rate on...

  10. Evolution of Titan's High-Pressure Ice layer (United States)

    Sotin, C.; Kalousova, K.


    Constraints on the present interior structure of Titan come from the gravity science experiment onboard the Cassini spacecraft and from the interpretation of the Extremely Low Frequency (ELF) wave observed by the Huygens probe [1, 2]. From the surface to the center, Titan would be composed of 4 layers: an icy crust, a global salty ocean, a layer of high-pressure ice (HP ice) and a core made of hydrated silicates [2, 3, 4]. The presence of a large amount of 40Ar in Titan's atmosphere argues for a geologically recent exchange process between the silicate core, where 40Ar is produced by the decay of 40K, and the atmosphere. Argon must then be able to be transported from the silicate core to the surface. This study investigates how volatiles can be transported through the HP ice layer.Recent numerical simulations [5] have demonstrated that the dynamics of the HP ice layer is controlled by convection processes in a two-phase material (water and high-pressure ice). The silicate / HP ice interface is maintained at the melting temperature, which might allow for the incorporation of volatiles such as 40Ar into the convecting HP ice. Above the hot thermal boundary layer, the temperature of the convecting HP ice is below the melting temperature, except for the upwelling plumes when they approach the cold thermal boundary layer. The upper part of the HP ice layer is at the melting point and permeable for water transport, providing a path for the transfer of volatiles trapped in the ice towards the ocean.Scaling laws are inferred from the numerical simulations [5]. They are then used to model the evolution of the HP ice layer. Specifically, we look at the effect of (i) ice viscosity, (ii) heat flux at the silicate/HP ice interface, and (iii) presence of anti-freeze compounds in the ocean, on the thickness of the HP ice layer. In addition, our results provide insights on possible resurfacing processes that could explain the geologically young age of Titan's surface. This work

  11. Viscosity and Solvation (United States)

    Robertson, C. T.


    Discusses theories underlying the phenomena of solution viscosities, involving the Jones and Dole equation, B-coefficient determination, and flickering cluster model. Indicates that viscosity measurements provide a basis for the study of the structural effects of ions in aqueous solutions and are applicable in teaching high school chemistry. (CC)

  12. Viscosity measuring using microcantilevers (United States)

    Oden, Patrick Ian


    A method for the measurement of the viscosity of a fluid uses a micromachined cantilever mounted on a moveable base. As the base is rastered while in contact with the fluid, the deflection of the cantilever is measured and the viscosity determined by comparison with standards.

  13. High-pressure synthesis of tantalum dihydride (United States)

    Kuzovnikov, Mikhail A.; Tkacz, Marek; Meng, Haijing; Kapustin, Dmitry I.; Kulakov, Valery I.


    The reaction of tantalum with molecular hydrogen was studied by x-ray diffraction in a diamond-anvil cell at room temperature and pressures from 1 to 41 GPa. At pressures up to 5.5 GPa, a substoichiometric tantalum monohydride with a distorted bcc structure was shown to be stable. Its hydrogen content gradually increased with the pressure increase, reaching H /Ta =0.92 (5 ) at 5 GPa. At higher pressures, a new dihydride phase of tantalum was formed. This phase had an hcp metal lattice, and its hydrogen content was virtually independent of pressure. When the pressure was decreased, the tantalum dihydride thus obtained transformed back to the monohydride at P =2.2 GPa . Single-phase samples of tantalum dihydride also were synthesized at a hydrogen pressure of 9 GPa in a toroid-type high-pressure apparatus, quenched to the liquid-N2 temperature, and studied at ambient pressure. X-ray diffraction showed them to have an hcp metal lattice with a =3.224 (3 ) and c =5.140 (5 )Å at T =85 K . The hydrogen content determined by thermal desorption was H /Ta =2.2 (1 ) .

  14. Engineering Model of High Pressure Moist Air

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš


    Full Text Available The article deals with the moist air equation of state. There are equations of state discussed in the article, i.e. the model of an ideal mixture of ideal gases, the model of an ideal mixture of real gases and the model based on the virial equation of state. The evaluation of sound speed based on the ideal mixture concept is mentioned. The sound speed calculated by the model of an ideal mixture of ideal gases is compared with the sound speed calculated by using the model based on the concept of an ideal mixture of real gases. The comparison of enthalpy end entropy based on the model of an ideal mixture of ideal gases and the model of an ideal mixture of real gases is performed. It is shown that the model of an ideal mixture of real gases deviates from the model of an ideal mixture of ideal gases only in the case of high pressure. An impossibility of the definition of partial pressure in the mixture of real gases is discussed, where the virial equation of state is used.

  15. High-pressure structures of yttrium hydrides (United States)

    Liu, Lu-Lu; Sun, Hui-Juan; Wang, C. Z.; Lu, Wen-Cai


    In this work, the crystal structures of YH3 and YH4 at high pressure (100-250 GPa) have been explored using a genetic algorithm combined with first-principles calculations. New structures of YH3 with space group symmetries of P21/m and I4/mmm were predicted. The electronic structures and the phonon dispersion properties of various YH3 and YH4 structures at different temperatures and pressures were investigated. Among YH3 phases, the P21/m structure of YH3 was found to have a relatively high superconducting transformation temperature T c of 19 K at 120 GPa, which is reduced to 9 K at 200 GPa. Other YH3 structures have much lower T cs. Compared with YH3, the T c of the YH4 compound is much higher, i.e. 94 K at 120 GPa and 55 K at 200 GPa.

  16. Recent progress in high-pressure studies on organic conductors

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata


    Full Text Available Recent high-pressure studies of organic conductors and superconductors are reviewed. The discovery of the highest Tc superconductivity among organics under high pressure has triggered the further progress of the high-pressure research. Owing to this finding, various organic conductors with the strong electron correlation were investigated under high pressures. This review includes the pressure techniques using the cubic anvil apparatus, as well as high-pressure studies of the organic conductors up to 10 GPa showing extraordinary temperature and pressure dependent transport phenomena.

  17. Pressure Dome for High-Pressure Electrolyzer (United States)

    Norman, Timothy; Schmitt, Edwin


    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  18. High Pressure Microwave Powered UV Light Sources (United States)

    Cekic, M.; Frank, J. D.; Popovic, S.; Wood, C. H.


    Industrial microwave powered (*electrodeless*) light sources have been limited to quiescent pressures of 300 Torr of buffer gas and metal- halide fills. Recently developed multi-atmospheric electronegative bu lb fills (noble gas-halide excimers, metal halide) require electric field s for ionization that are often large multiples of the breakdown voltage for air. For these fills an auxiliary ignition system is necessary. The most successful scheme utilizes a high voltage pulse power supply and a novel field emission source. Acting together they create localized condition of pressure reduction and high free electron density. This allows the normal microwave fields to drive this small region into avalanche, ignite the bulb, and heat the plasma to it's operating poin t Standard diagnostic techniques of high density discharges are inapplicable to the excimer bulbs, because of the ionic molecular exci ted state structure and absence of self-absorption. The method for temperature determination is based on the equilibrium population of certain vibrational levels of excimer ionic excited states. Electron d ensity was determined from the measurements of Stark profiles of H_β radiation from a small amount of hydrogen mixed with noble gas and halogens. At the present time, high pressure (Te 0.5eV, ne 3 x 10^17 cm-3) production bulbs produce over 900W of radiation in a 30nm band, centered at 30nm. Similarly, these prototypes when loaded with metal-halide bulb fills produce 1 kW of radiation in 30nm wide bands, centered about the wavelength of interest.

  19. Cobalt ferrite nanoparticles under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V. [Instituto de Tecnologías y Ciencias de la Ingeniería, “Ing. H. Fernández Long,” Av. Paseo Colón 850 (1063), Buenos Aires (Argentina); Errandonea, D., E-mail: [Departamento de Fisica Aplicada, Institut Universitari de Ciència dels Materials, Universitat de Valencia, c/ Doctor Moliner 50, E-46100 Burjassot, Valencia (Spain); Agouram, S. [Departamento de Física Aplicada y Electromagnetismo, Universitat de València, 46100 Burjassot, Valencia (Spain)


    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  20. Viscosity jump in the lower mantle inferred from melting curves of ferropericlase. (United States)

    Deng, Jie; Lee, Kanani K M


    Convection provides the mechanism behind plate tectonics, which allows oceanic lithosphere to be subducted into the mantle as "slabs" and new rock to be generated by volcanism. Stagnation of subducting slabs and deflection of rising plumes in Earth's shallow lower mantle have been suggested to result from a viscosity increase at those depths. However, the mechanism for this increase remains elusive. Here, we examine the melting behavior in the MgO-FeO binary system at high pressures using the laser-heated diamond-anvil cell and show that the liquidus and solidus of (Mg x Fe 1-x )O ferropericlase (x = ~0.52-0.98), exhibit a local maximum at ~40 GPa, likely caused by the spin transition of iron. We calculate the relative viscosity profiles of ferropericlase using homologous temperature scaling and find that viscosity increases 10-100 times from ~750 km to ~1000-1250 km, with a smaller decrease at deeper depths, pointing to a single mechanism for slab stagnation and plume deflection.

  1. Tidal viscosity of Enceladus (United States)

    Efroimsky, Michael


    In the preceding paper (Efroimsky, 2017), we derived an expression for the tidal dissipation rate in a homogeneous near-spherical Maxwell body librating in longitude. Now, by equating this expression to the outgoing energy flux due to the vapour plumes, we estimate the mean tidal viscosity of Enceladus, under the assumption that the Enceladean mantle behaviour is Maxwell. This method yields a value of 0.24 × 1014 Pa s for the mean tidal viscosity, which is very close to the viscosity of ice near the melting point.

  2. High-pressure behavior of nano titanium dioxide

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Jiang, Jianzhong


    Nanocrystalline rutile Titanium dioxide has been studied by X-ray diffraction at ambient temperature up to 47.4 GPa. The material is found to transform to the monoclinic baddeleyite structure between 20 and 30 GPa, which is higher than the corresponding pressure range for bulk material. Upon...... decompression, the baddeleyite phase transforms to the alpha-PbO2 phase at about 4-2 GPa. The experimental bulk moduli are 211(7) GPa for the rutile phase, 235(16) for the baddeleyite type and 212(25) GPa for the alpha-PbO2 type phase. The results are compared with previous measurements of bulk rutile Titanium...

  3. Dynamic High-Pressure Behavior of Hierarchical Heterogeneous Geological Materials (United States)


    Taylor, N. E., Jardine, A. P., Behaviour of sand during release from a shocked state, Applied Physics Letters 103, 154103 (2013); doi: 10.1063...V., and M. N. Pavlovskii (1971), Response of clay and clay shale to heavy dynamic loading, Journal of Applied Mechanics and Technical Physics , 1, 161...multiple mechanisms in simulations 15.  SUBJECT TERMS High-rate Deformation, Heterogeneous Materials, Shock Physics Standard Form 298 (Rev. 8/98

  4. Geomechaical Behavior of Shale Rocks Under High Pressure and Temperature (United States)

    Villamor Lora, R.; Ghazanfari, E.


    The mechanical properties of shale are demanding parameters for a number of engineering and geomechanical purposes. Borehole stability modeling, geophysics, shale oil and shale gas reservoirs, and underground storage of CO2 in shale formations are some of these potential applications to name a few. The growing interest in these reservoirs, as a source for hydrocarbons production, has resulted in an increasing demand for fundamental rock property data. These rocks are known to be non-linear materials. There are many factors, including induced cracks and their orientation, partial saturation, material heterogeneity and anisotropy, plasticity, strain rate, and temperature that may have an impact on the geomechanical behaviour of these shales.Experimental results and theoretical considerations have shown that the elastic moduli are not single-value, well-defined parameters for a given rock. Finding suitable values for these parameters is of vital importance in many geomechanical applications. In this study, shale heterogeneity and its geomechanical properties are explored through an extensive laboratory experimental program. A series of hydrostatic and triaxial tests were performed in order to evaluate the elasticity, viscoplasticity, yielding and failure response of Marcellus shale samples as a function of pressure and temperature. Additional characterization includes mineralogy, porosity, and permeability measurements. The shale samples were taken from a Marcellus outcrop at State Game Lands 252, located in Lycoming and Union counties, Allenwood, Pennsylvania. Laboratory experiments have shown that creep behaviour is highly sensitive to temperature. Furthermore, the non-linear nature of these rocks reveals interesting behaviour of the elastic moduli highly dependent on stress history of the rock. Results from cyclic triaxial tests point out the different behaviour between 1st-loading and unloading-reloading cycles. Experimental results of these Marcellus shales are compared with other shales from different plays in the United States.

  5. Nanocomposite Thermolectric Materials by High Pressure Powder Consolidation Manufacturing Project (United States)

    National Aeronautics and Space Administration — In response to NASA's need to develop advanced nanostructured thermolectric materials, UTRON is proposing an innovative high pressure powder consolidation...

  6. Effect of oxidation on base liquids of oil and synthetic-based drilling fluids at high pressure and high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Shahbazi, K.; Mehta, S.A.; Moore, R.G.; Ursenbach, M.G. [Calgary Univ., AB (Canada)


    Diesels and distillates are used as a base liquid for most oil-based drilling fluids in conventional drilling and as the liquid phase in gasified liquids in some underbalanced drilling operations. They are also used as friction reducing agents to free stuck pipes. It is important to understand the true downhole rheological properties because they affect equivalent circulating density, hole cleaning, barite sag, surge/swab pressures during tripping, pump pressure and bit hydraulics. Also, gelation and high viscosity are major concerns, particularly at high temperatures. An experimental study was conducted to evaluate the effect of oxidation on some base liquids for oil-based and synthetic-based drilling fluids at high pressures and high temperatures. Gas and liquid phases were characterized and the solid phase was measured along with viscosity measurements at temperatures and pressures ranging from 20 to 152 degrees C at atmospheric pressures to 103.4 MPa. The viscosity of the liquid samples after aging was compared with that of corresponding fresh samples. The results indicate that the degree of oxidation plays an important role in increasing the sample viscosity. The increase in viscosity depends on temperature, and is more significant at low temperatures. Agitation of samples during aging with air resulted in increased amounts of solid precipitation while lowering the viscosity of the liquid phase. This study demonstrated that oxidation has an important influence on rheological properties of the oil, because it affects the mobility of the oil and therefore the recovery factor. 11 refs., 7 tabs., 22 figs.

  7. Viscosity Measurements and Correlations for 1,1,1,2-tetrafluoroethane (HFC-134a) up to 140 MPa

    DEFF Research Database (Denmark)

    Comuñas, M.J.P.; Baylaucq, A.; Cisneros, Sergio


    In spite of being one of the most studied refrigerants, large discrepancies in the experimental determination of the dynamic viscosity of 1, 1, 1,2-tetrafluoroethane (HFC-134a) prevail. Additionally, there is a need for supplementary high-pressure measurements that can help to derive sound general...... correlations for the viscosity of this compound. Hence, in this work new dynamic viscosity measurements for HFC-134a using a falling-body viscometer in the temperature range of 293.15-373.15 K and pressures up to 140 MPa are presented. This work high-pressure data in combination with already published data...... provide dynamic viscosity information for the HFC-134a on wide ranges of temperature and pressure. Thus, based on selected HFC-134a viscosity measurements, a representative viscosity model has been correlated using the friction theory (f-theory) in combination with a BWR type of equation of state (Eo...

  8. Imaging aerosol viscosity (United States)

    Pope, Francis; Athanasiadis, Thanos; Botchway, Stan; Davdison, Nicholas; Fitzgerald, Clare; Gallimore, Peter; Hosny, Neveen; Kalberer, Markus; Kuimova, Marina; Vysniauskas, Aurimas; Ward, Andy


    Organic aerosol particles play major roles in atmospheric chemistry, climate, and public health. Aerosol particle viscosity is important since it can determine the ability of chemical species such as oxidants, organics or water to diffuse into the particle bulk. Recent measurements indicate that OA may be present in highly viscous states; however, diffusion rates of small molecules such as water appear not to be limited by these high viscosities. We have developed a technique for measuring viscosity that allows for the imaging of aerosol viscosity in micron sized aerosols through use of fluorescence lifetime imaging of viscosity sensitive dyes which are also known as 'molecular rotors'. These rotors can be introduced into laboratory generated aerosol by adding minute quantities of the rotor to aerosol precursor prior to aerosolization. Real world aerosols can also be studied by doping them in situ with the rotors. The doping is achieved through generation of ultrafine aerosol particles that contain the rotors; the ultrafine aerosol particles deliver the rotors to the aerosol of interest via impaction and coagulation. This work has been conducted both on aerosols deposited on microscope coverslips and on particles that are levitated in their true aerosol phase through the use of a bespoke optical trap developed at the Central Laser Facility. The technique allows for the direct observation of kinetic barriers caused by high viscosity and low diffusivity in aerosol particles. The technique is non-destructive thereby allowing for multiple experiments to be carried out on the same sample. It can dynamically quantify and track viscosity changes during atmospherically relevant processes such oxidation and hygroscopic growth (1). This presentation will focus on the oxidation of aerosol particles composed of unsaturated and saturated organic species. It will discuss how the type of oxidant, oxidation rate and the composition of the oxidized products affect the time

  9. Band structure and phonon properties of lithium fluoride at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, J. M., E-mail: [Government Engineering College, Gandhinagar 382028, Gujarat (India); Department of Physics, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat (India); Joshi, Mitesh [Government Polytechnic for Girls, Athwagate, Surat395001, Gujarat (India); Gajjar, P. N., E-mail: [Department of Physics, University School of Sciences, Gujarat University, Ahmedabad 380009, Gujarat (India)


    High pressure structural and electronic properties of Lithium Fluoride (LiF) have been studied by employing an ab-initio pseudopotential method and a linear response scheme within the density functional theory (DFT) in conjunction with quasi harmonic Debye model. The band structure and electronic density of states conforms that the LiF is stable and is having insulator behavior at ambient as well as at high pressure up to 1 Mbar. Conclusions based on Band structure, phonon dispersion and phonon density of states are outlined.

  10. Effects of high-pressure processing (HPP) on the microbiological ...

    African Journals Online (AJOL)



    Dec 29, 2009 ... High pressure processing (HPP) is an increasingly popular food processing method that offers great potential within the food industry. ... Key words: High pressure processing, fresh cheese, dairy, spoilage. INTRODUCTION. Food ..... chemical reactions and genetic mechanisms. Primarily,. HP treatment ...

  11. High Pressure Research on Materials-Experimental Techniques to ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 8. High Pressure Research on Materials - Experimental Techniques to Study the Behaviour of Materials Under High Pressure. P Ch Sahu N V Chandra Shekar. General Article Volume 12 Issue 8 August 2007 pp 49-64 ...

  12. Quantum effects in condensed matter at high pressure

    CERN Document Server

    Stishov, S M


    Experimental data on the influence of quantum effects on the equation of state and melting at high pressure are reviewed. It is shown that quantum isotopic effects tend to increase upon compression of substances with predominately Coulomb interaction, whereas compression of the van der Waals substances reveals the opposite trend. The cold melting of Coulomb substances at high pressure is discussed

  13. Apple peel-based edible film development using a high-pressure homogenization. (United States)

    Sablani, Shyam S; Dasse, Florian; Bastarrachea, Luis; Dhawan, Sumeet; Hendrix, Kathleen M; Min, Sea C


    Biopolymer films were developed from apple peels of apple process co-products and their physical properties were determined. Apple peel-based films with glycerol (23%, 33%, and 44%[w/w, dry basis]) were prepared using high-pressure homogenization (HPH) at different levels of pressure (138, 172, and 207 MPa). An evaluation of the rheological properties (elastic modulus [G'], viscous modulus [G''], and viscosity) of the film-forming solutions was performed. For the apple peel films, the water sorption isotherms, the kinetics of water absorption, the water vapor permeability (WVP), the oxygen permeability (OP), and the tensile properties were determined. The G' and viscosity of the film-forming solutions decreased significantly with increasing processing pressure (P pressures (P > 0.05). The viscosity decreased from 644 to 468 kPa.s as the pressure increased from 138 to 207 MPa at 90 degrees C. The monolayer water content of the apple peel films decreased with increasing content of glycerol from 23% to 33%. Further increase in glycerol content did not change the monolayer water content. The water diffusion coefficient of the films was highest at the intermediate level of glycerol content. The barrier properties (WVP and OP) of the films increased with increasing level of glycerol, while processing pressure did not influence the gas barrier properties. The films prepared at 207 MPa were less stiff and strong, but more stretchable than those prepared at 138 and 172 MPa.

  14. Thermoelectric properties of high pressure synthesized lithium and calcium double-filled CoSb3

    Directory of Open Access Journals (Sweden)

    Xiaohui Li


    Full Text Available Lithium and calcium are inefficient filling elements of CoSb3 at ambient pressure, but show nice filling behavior under high pressure. In this work, we synthesized Li/Ca double-filled CoSb3 with high pressure synthesis method. The products show the skutterudite structure of Im3¯ symmetry. Thermoelectric properties were effectively enhanced through Li and Ca co-filling. For the optimal Li0.08Ca0.18Co4Sb12 sample, the power factor maintains a relatively high value over the whole measurement temperature range and peaks at 4700μWm−1K−2, meanwhile the lattice thermal conductivity is greatly suppressed, leading to a maximal ZT of 1.18 at 700 K. Current work demonstrates high pressure synthesis as an effective method to produce multiple elemental filled CoSb3 skutterudites.

  15. High-Pressure Study on Lead Fluorapatite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.; Shieh, S; Fleet, M; Akhmetov, A


    The compressional behavior of a synthetic lead fluorapatite [Pb9.35(PO4)6F2] has been investigated in situ up to about 16.7 GPa at 300 K, using a diamond-anvil cell and synchrotron X-ray diffraction. We find that the compressibility of lead fluorapatite is significantly different from that of fluorapatite [Ca10(PO4)6F2], chlorapatite [Ca10(PO4)6Cl2], and hydroxylapatite [Ca10(PO4)6(OH)2]: lead fluorapatite is much more compressible, and elastically isotropic in the investigated pressure range. The pressure-volume data fitted to the third-order Birch-Murnaghan equation yield an isothermal bulk modulus (KT) of 54.3(18) GPa and the pressure derivative (KT') of 8.1(6). If KT' is fixed at 4, the obtained KT is 68.4(16) GPa, which is approximately only two-thirds of the isothermal bulk modulus of the calcium apatites.

  16. Ultrasonic depth gauge for liquids under high pressure (United States)

    Zuckerwar, Allan J. (Inventor); Mazel, David S. (Inventor)


    The invention relates to an ultrasonic depth gauge for liquids under high pressure and is particularly useful in the space industry where it is necessary to use a pressurized gas to transfer a liquid from one location to another. Conventional liquid depth gauges do not have the capability to operate under extreme high pressure (i.e., exceeding 300 psi). An ultrasonic depth gauge capable of withstanding high pressure according to the present invention is comprised of a transducer assembly and a supporting electronics unit. The former is mounted in to the bottom wall of a storage vessel with its resonating surface directly exposed to the highly pressurized liquid in the vessel. In operation, the ultrasonic pulse propagates upward through the liquid to the liquid-gas interface in the storage vessel. When the ultrasonic echo returns from the liquid-gas interface, it re-excites the composite resonator into vibration. The supporting electronics unit measures the round-trip transmit time for the ultrasonic pulse and its return echo to traverse the depth of the highly pressurized liquid. The novelty of the invention resides in the use of a conventional transducer rigidly bonded to the inside wall of a bored out conventional high-pressure plug to form a composite resonator capable of withstanding extremely high pressure.

  17. Plastic deformation of silicate garnets. I. High-pressure experiments (United States)

    Voegelé, V.; Ando, J. I.; Cordier, P.; Liebermann, R. C.

    Deformation experiments have been carried out on garnet single crystals (Py20 Al73 Sp2 Gr5) under high confining pressure (6.5 GPa) and temperatures in the range 700-1440°C. The high-pressure sample assembly was designed to generate high differential stress. Below 1000°C, the specimens show only evidence of microplasticity associated with microcracking. Above 1000°C, garnet become ductile and the microstructure is characteristic of dislocation creep with significant recovery. The observed glide systems are 1/2{11¯0}, 1/2{112¯}, 1/2{123¯}, {010} and {011} in the whole temperature range. The most stable (and hence less mobile) dislocation lines appear to be the 70° 1/2 (i.e., with a large edge component) and edge . Except for some rare dislocations generated at low temperature, most of the dislocations exhibit no visible dissociation. The detailed characterization of the dislocations suggests that they have an extended, non-planar core. This core structure induces a high Peierls friction and is responsible for the brittle behavior of garnets at low temperature. The Peierls regime extends up to high temperature until diffusion takes place and enhances dislocation climb superimposed to glide.

  18. Rapid Heat Treatment of Aluminum High-Pressure Diecastings (United States)

    Lumley, R. N.; Polmear, I. J.; Curtis, P. R.


    Recently, it has been demonstrated that common high-pressure diecasting (HPDC) alloys, such as those based on the Al-Si-Cu and Al-Si-Mg-(Cu) systems, may be successfully heat treated without causing surface blistering or dimensional instability. In some compositions, the capacity to exploit age hardening may allow the proof stress values to be doubled when compared to the as-cast condition. This heat treatment procedure involves the use of severely truncated solution treatment cycles conducted at lower than normal temperatures, followed by quenching and natural or artificial aging. The potential therefore exists to develop and evaluate secondary HPDC alloys designed specifically for rapid heat treatment, while still displaying high castability. This article reports results of an experimental program in which responses of various alloy compositions to age hardening have been investigated with the primary aim of further reducing the duration and cost of the heat treatment cycle while maintaining high tensile properties. Composition ranges have been established for which values of 0.2 pct proof stress exceeding 300 MPa ( i.e., increases of ~100 pct above as-cast values) can be achieved using a procedure that involves a total time for solution treatment plus age hardening of only 30 minutes. This rapid aging behavior is shown to be related to precipitation of the complex Q' phase, which forms primarily when Mg contents of the alloys are above ~0.2 wt pct.

  19. Feeding Mechanisms in High-Pressure Die Castings (United States)

    Otarawanna, S.; Laukli, H. I.; Gourlay, C. M.; Dahle, A. K.


    This work focuses on understanding the feeding behavior during high-pressure die casting (HPDC). The effects of intensification pressure (IP) and gate thickness on the transport of material through the gate during the latter stages of HPDC were investigated using an AlSi3MgMn alloy. Microstructural characterization of the gate region indicated a marked change in feeding mechanism with increasing IP and gate size. Castings produced with a high IP or thick gate contained a relatively low fraction of total porosity, and shear band-like features existed through the gate, suggesting that semisolid strain localization in the gate is involved in feeding during the pressure intensification stage. When a low IP is combined with a thin gate, no shear band is observed in the gate and feeding is less effective, resulting in a higher level of porosity in the HPDC component. Although shear banding through the gate was found to reduce porosity in HPDC parts, if gates are not properly designed, deformation of the mushy zone through the gate can cause severe macrosegregation, large pores, and large cracks, which could severely reduce the performance of the component.

  20. Microorganisms under high pressure--adaptation, growth and biotechnological potential. (United States)

    Mota, Maria J; Lopes, Rita P; Delgadillo, Ivonne; Saraiva, Jorge A


    Hydrostatic pressure is a well-known physical parameter which is now considered an important variable of life, since organisms have the ability to adapt to pressure changes, by the development of resistance against this variable. In the past decades a huge interest in high hydrostatic pressure (HHP) technology is increasingly emerging among food and biosciences researchers. Microbial specific stress responses to HHP are currently being investigated, through the evaluation of pressure effects on biomolecules, cell structure, metabolic behavior, growth and viability. The knowledge development in this field allows a better comprehension of pressure resistance mechanisms acquired at sub-lethal pressures. In addition, new applications of HHP could arise from these studies, particularly in what concerns to biotechnology. For instance, the modulation of microbial metabolic pathways, as a response to different pressure conditions, may lead to the production of novel compounds with potential biotechnological and industrial applications. Considering pressure as an extreme life condition, this review intends to present the main findings so far reported in the scientific literature, focusing on microorganisms with the ability to withstand and to grow in high pressure conditions, whether they have innated or acquired resistance, and show the potential of the application of HHP technology for microbial biotechnology. © 2013.

  1. "Understanding" cosmological bulk viscosity


    Zimdahl, Winfried


    A universe consisting of two interacting perfect fluids with the same 4-velocity is considered. A heuristic mean free time argument is used to show that the system as a whole cannot be perfect as well but neccessarily implies a nonvanishing bulk viscosity. A new formula for the latter is derived and compared with corresponding results of radiative hydrodynamics.

  2. Viscosity of colloidal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, E.G.D. [Rockefeller Univ., New York, NY (United States); Schepper, I.M. de [Delft Univ. of Technology (Netherlands)


    Simple expressions are given for the effective Newtonian viscosity as a function of concentration as well as for the effective visco-elastic response as a function of concentration and imposed frequency, of monodisperse neutral colloidal suspensions over the entire fluid range. The basic physical mechanisms underlying these formulae are discussed. The agreement with existing experiments is very good.

  3. Safety analysis of high pressure gasous fuel container punctures

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.R. [Univ. of Miami, Coral Gables, FL (United States)


    The following report is divided into two sections. The first section describes the results of ignitability tests of high pressure hydrogen and natural gas leaks. The volume of ignitable gases formed by leaking hydrogen or natural gas were measured. Leaking high pressure hydrogen produced a cone of ignitable gases with 28{degrees} included angle. Leaking high pressure methane produced a cone of ignitable gases with 20{degrees} included angle. Ignition of hydrogen produced larger overpressures than did natural gas. The largest overpressures produced by hydrogen were the same as overpressures produced by inflating a 11 inch child`s balloon until it burst.

  4. Implement and application of ultra-high pressures environment (United States)

    Xian Zhang, Yu; Li, Nan; Liu, Bin Bin; Wang, Hong


    A hydraulic system was designed which was used to generate hydrostatic ultra-high pressure environment. The functions and roles of the main elements in the hydraulic system were introduced. Deformation theory based on ultrahigh pressure cylinder was analyzed. The principle and method about measuring ultra-high pressure cylinder radial and circumferential elastic line-strain by a dial indicator were illustrated. A practical example was given to illustrate the practicability and validity of this method. The measures to decrease the measurement error were pointed out. The described priciples and methods have a certain theoretical and practical significance in engineering research and application of ultra-high pressure.

  5. Public debate on metallic hydrogen to boost high pressure research

    Directory of Open Access Journals (Sweden)

    Hua Y. Geng


    Full Text Available Instead of praises from colleagues, the claim of observation of metallic hydrogen at 495 GPa by Dias and Silvera met much skepticism, and grew into a public debate at the International Conference on High-Pressure Science and Technology, AIRAPT26. We briefly review this debate, and extend the topic to show that this disputation could be an opportunity to benefit the whole high pressure community. Keywords: High pressure, Metallic hydrogen, Quantum solid and liquid, Phase stability, Superconductivity, PACS codes: 61.50.Ks, 67.63.-r, 67.80.-s, 71.30.+h, 74.62.Fj

  6. Shear viscosity of an ordering latex suspension

    NARCIS (Netherlands)

    van der Vorst, A.M.; van der Vorst, B.; van den Ende, Henricus T.M.; Aelmans, N.J.J.; Mellema, J.


    The shear viscosity of a latex which is ordered at rest is studied as a function of the shear rate and volume fraction. At low shear rates and for moderate to high volume fractions, the flow curves show dynamic yield behavior which disappears below a volume fraction of 8%. At high shear rates, the

  7. High pressure and microwave based synthesis of transition metal pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Pobel, Roman Rupert


    The goal of this thesis was to explore the possibilities of synthetic methods that are not very common in current transition metal pnictide research. The substitution of the Ca-site in CaFe{sub 2}As{sub 2} with rare earth elements such as Pr the has been reported to induce superconductivity. However, some inconsistencies in the data suggested a non-intrinsic origin of the observed diamagnetic signal. Furthermore a solubility limit of 13% was found when prepared in an electrical furnace thus leaving a huge part of the physical phase diagram inaccessible. A high pressure/high temperature synthesis was developed to allow access to the whole doping range and an in-depth characterization of this compound was carried out. During the experiments concerning the high pressure synthesis of Ca{sub 1-x}Pr{sub x}Fe{sub 2}As{sub 2} the new ternary iron arsenide CaFe{sub 5}As{sub 3} was identified and classified as a member of the Ca{sub n(n+1)/2}(Fe{sub 1-x}M{sub x}){sub (2+3n)}M'{sub n(n-1)/2}As{sub (n+1)(n+2)/2} (n = 1-3; M =Nb, Pd, Pt; M' = □, Pd, Pt) family. The complete solid solution Ca{sub 1-x}Pr{sub x}Fe{sub 5}As{sub 3} (O ≤ x ≤ 1) was prepared and physically characterized. Furthermore, several useful techniques were developed to aid in future high pressure based investigations of transition metal pnictides. The second part of this thesis concerns a completely different, but equally promising synthetic approach. Microwave based synthesis is a well-established technique in many solution based fields, such as organic, medicinal or nano chemistry. For solid state and materials research several parameters and particularities have to be considered. But when successful, it allows for the reduction of reaction time by several orders of magnitude. It has very rarely been applied in the preparation of pnictides and on1y once in the context of pnictide superconductor research. The possibilities of this method were explored and employed in the preparation of several

  8. The high pressure gas Cerenkov counter at the Omega Facility.

    CERN Multimedia


    The high-pressure gas Cerenkov was used to measure reactions as pion (or kaon)- hydrogen --> forward proton - X. It was built by the Ecole Polytechnique (Palaiseu). Here Peter Sonderegger and Patrick Fleury,

  9. Beam steering effects in turbulent high pressure flames

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    The propagation of a laser beam through a flame is influenced by variations of the optical density. Especially in turbulent high pressure flames this may seriously limit the use of laser diagnostic methods. (author) 1 fig., 2 refs.

  10. Novel High Pressure Pump-on-a-Chip Technology Project (United States)

    National Aeronautics and Space Administration — HJ Science & Technology, Inc proposes to develop a novel high pressure "pump-on-a-chip" and "valve-on-a-chip" microfluidic technology for NASA planetary science...

  11. Monitoring protein folding through high pressure NMR spectroscopy. (United States)

    Roche, Julien; Royer, Catherine A; Roumestand, Christian


    High-pressure is a well-known perturbation method used to destabilize globular proteins. It is perfectly reversible, which is essential for a proper thermodynamic characterization of a protein equilibrium. In contrast to other perturbation methods such as heat or chemical denaturant that destabilize protein structures uniformly, pressure exerts local effects on regions or domains of a protein containing internal cavities. When combined with NMR spectroscopy, hydrostatic pressure offers the possibility to monitor at a residue level the structural transitions occurring upon unfolding and to determine the kinetic properties of the process. High-pressure NMR experiments can now be routinely performed, owing to the recent development of commercially available high-pressure sample cells. This review summarizes recent advances and some future directions of high-pressure NMR techniques for the characterization at atomic resolution of the energy landscape of protein folding. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. A high-pressure MWPC detector for crystallography

    DEFF Research Database (Denmark)

    Ortuno-Prados, F.; Bazzano, A.; Berry, A.


    The application of the Multi-Wire Proportional Counter (MWPC) as a potential detector for protein crystallography and other wide-angle diffraction experiments is presented. Electrostatic problems found with our large area MWPC when operated at high pressure are discussed. We suggest that a soluti...... to these problems is to use a glass micro-strip detector in place of the wire frames. The characteristics of a high-pressure Micro-Strip Gas Chamber (MSGC) tested in the laboratory are presented....

  13. High-pressure crystallography of periodic and aperiodic crystals

    Directory of Open Access Journals (Sweden)

    Clivia Hejny


    Full Text Available More than five decades have passed since the first single-crystal X-ray diffraction experiments at high pressure were performed. These studies were applied historically to geochemical processes occurring in the Earth and other planets, but high-pressure crystallography has spread across different fields of science including chemistry, physics, biology, materials science and pharmacy. With each passing year, high-pressure studies have become more precise and comprehensive because of the development of instrumentation and software, and the systems investigated have also become more complicated. Starting with crystals of simple minerals and inorganic compounds, the interests of researchers have shifted to complicated metal–organic frameworks, aperiodic crystals and quasicrystals, molecular crystals, and even proteins and viruses. Inspired by contributions to the microsymposium `High-Pressure Crystallography of Periodic and Aperiodic Crystals' presented at the 23rd IUCr Congress and General Assembly, the authors have tried to summarize certain recent results of single-crystal studies of molecular and aperiodic structures under high pressure. While the selected contributions do not cover the whole spectrum of high-pressure research, they demonstrate the broad diversity of novel and fascinating results and may awaken the reader's interest in this topic.

  14. Viscosity of Xenon Examined in Microgravity (United States)

    Zimmerli, Gregory A.; Berg, Robert F.; Moldover, Michael R.


    Why does water flow faster than honey? The short answer, that honey has a greater viscosity, merely rephrases the question. The fundamental answer is that viscosity originates in the interactions between a fluid s molecules. These interactions are so complicated that, except for low-density gases, the viscosity of a fluid cannot be accurately predicted. Progress in understanding viscosity has been made by studying moderately dense gases and, more recently, fluids near the critical point. Modern theories predict a universal behavior for all pure fluids near the liquid-vapor critical point, and they relate the increase in viscosity to spontaneous fluctuations in density near this point. The Critical Viscosity of Xenon (CVX) experiment tested these theories with unprecedented precision when it flew aboard the Space Shuttle Discovery (STS-85) in August 1997. Near the critical point, xenon is a billion times more compressible than water, yet it has about the same density. Because the fluid is so "soft," it collapses under its own weight when exposed to the force of Earth s gravity - much like a very soft spring. Because the CVX experiment is conducted in microgravity, it achieves a very uniform fluid density even very close to the critical point. At the heart of the CVX experiment is a novel viscometer built around a small nickel screen. An oscillating electric field forces the screen to oscillate between pairs of electrodes. Viscosity, which dampens the oscillations, can be calculated by measuring the screen motion and the force applied to the screen. So that the fluid s delicate state near the critical point will not be disrupted, the screen oscillations are set to be both slow and small.

  15. Enhancement of yield point at high pressure high temperature wells by using polymer nanocomposites based on ZnO & CaCO3 nanoparticles

    Directory of Open Access Journals (Sweden)

    A.Z. Noah


    Full Text Available Zinc oxide nanoparticles (ZnO-NPs and modified calcium carbonate (nano-CaCO3 nanoparticles were successfully prepared and added to polystyrene-butadiene rubber copolymer (PSBR matrix to prepare PSBR nanocomposites. The prepared nanomaterials (ZnO-NPs & nano-CaCO3 were characterized using scanning electron microscope (SEM, transmission electron microscope (TEM and X-ray diffraction (XRD. Furthermore, the prepared polymer nanocomposites and oil base mud were used for drilling in high pressure high temperature (HPHT wells. The consequence of using polymer nanocomposites based on different loading of ZnO-NPs and nano-CaCO3 on the rheological properties of oil base mud was evaluated and enhanced the yield point at high pressure high temperature wells (HPHT. The using of the polymer with different percentage from (0.5 in all percent the obtained results is very promising; this means that the increase of polymer is reasonable for the increase of apparent viscosity, plastic viscosity and yield point at high temperature. Correspondingly, polymer nanocomposites displayed rise of apparent viscosity, plastic viscosity, and yield point, decreased in fluid loss and increased in electrical stability at high pressure high temperature wells.

  16. Skyrmions and Hall viscosity


    Kim, Bom Soo


    We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physica...

  17. Early dissipation and viscosity


    Bozek, Piotr


    We consider dissipative phenomena due to the relaxation of an initial anisotropic local pressure in the fireball created in relativistic heavy-ion collisions, both for the Bjorken boost-invariant case and for the azimuthally symmetric radial expansion with boost-invariance. The resulting increase of the entropy can be counterbalanced by a suitable retuning of the initial temperature. An increase of the transverse collective flow is observed. The influence of the shear viscosity on the longitu...

  18. Solvated fullerenes, a new class of carbon materials suitable for high-pressure studies: A review (United States)

    Wang, Lin


    As the list of known carbon compounds grows longer, solvated fullerenes have become a more important class of carbon materials. Their general properties and methods of synthesis have both attracted considerable attention. The study of the behavior of these compounds under high-pressure conditions has revealed several new phenomena that have never been observed in pure fullerene. This article is a review of all recent progress in this field.

  19. Effect of high pressure processing on rheological and structural properties of milk-gelatin mixtures. (United States)

    Devi, Anastasia Fitria; Liu, Li Hui; Hemar, Yacine; Buckow, Roman; Kasapis, Stefan


    There is an increasing demand to tailor the functional properties of mixed biopolymer systems that find application in dairy food products. The effect of static high pressure processing (HPP), up to 600MPa for 15min at room temperature, on milk-gelatin mixtures with different solid concentrations (5%, 10%, 15% and 20% w/w milk solid and 0.6% w/w gelatin) was investigated. The viscosity remarkably increased in mixtures prepared with high milk solid concentration (15% and 20% w/w) following HPP at 300MPa, whereas HPP at 600MPa caused a decline in viscosity. This was due to ruptured aggregates and phase separation as confirmed by confocal laser scanning microscopy. Molecular bonding of the milk-gelatin mixtures due to HPP was shown by Fourier-transform infrared spectra, particularly within the regions of 1610-1690 and 1480-1575cm(-1), which reflect the vibrational bands of amide I and amide II, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Decomposition of silicon carbide at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daviau, Kierstin; Lee, Kanani K. M.


    We measure the onset of decomposition of silicon carbide, SiC, to silicon and carbon (e.g., diamond) at high pressures and high temperatures in a laser-heated diamond-anvil cell. We identify decomposition through x-ray diffraction and multiwavelength imaging radiometry coupled with electron microscopy analyses on quenched samples. We find that B3 SiC (also known as 3C or zinc blende SiC) decomposes at high pressures and high temperatures, following a phase boundary with a negative slope. The high-pressure decomposition temperatures measured are considerably lower than those at ambient, with our measurements indicating that SiC begins to decompose at ~ 2000 K at 60 GPa as compared to ~ 2800 K at ambient pressure. Once B3 SiC transitions to the high-pressure B1 (rocksalt) structure, we no longer observe decomposition, despite heating to temperatures in excess of ~ 3200 K. The temperature of decomposition and the nature of the decomposition phase boundary appear to be strongly influenced by the pressure-induced phase transitions to higher-density structures in SiC, silicon, and carbon. The decomposition of SiC at high pressure and temperature has implications for the stability of naturally forming moissanite on Earth and in carbon-rich exoplanets.

  1. High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant

    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, E A; Tan, N


    High pressure deflagration rate measurements of a unique ammonium perchlorate (AP) based propellant are required to design the base burn motor for a Raytheon weapon system. The results of these deflagration rate measurements will be key in assessing safety and performance of the system. In particular, the system may experience transient pressures on the order of 100's of MPa (10's kPSI). Previous studies on similar AP based materials demonstrate that low pressure (e.g. P < 10 MPa or 1500 PSI) burn rates can be quite different than the elevated pressure deflagration rate measurements (see References and HPP results discussed herein), hence elevated pressure measurements are necessary in order understand the deflagration behavior under relevant conditions. Previous work on explosives have shown that at 100's of MPa some explosives will transition from a laminar burn mechanism to a convective burn mechanism in a process termed deconsolidative burning. The resulting burn rates that are orders-of-magnitude faster than the laminar burn rates. Materials that transition to the deconsolidative-convective burn mechanism at elevated pressures have been shown to be considerably more violent in confined heating experiments (i.e. cook-off scenarios). The mechanisms of propellant and explosive deflagration are extremely complex and include both chemical, and mechanical processes, hence predicting the behavior and rate of a novel material or formulation is difficult if not impossible. In this work, the AP/HTPB based material, TAL-1503 (B-2049), was burned in a constant volume apparatus in argon up to 300 MPa (ca. 44 kPSI). The burn rate and pressure were measured in-situ and used to calculate a pressure dependent burn rate. In general, the material appears to burn in a laminar fashion at these elevated pressures. The experiment was reproduced multiple times and the burn rate law using the best data is B = (0.6 {+-} 0.1) x P{sup (1.05{+-}0.02)} where B is the burn

  2. High-Pressure Design of Advanced BN-Based Materials

    Directory of Open Access Journals (Sweden)

    Oleksandr O. Kurakevych


    Full Text Available The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN with hardness comparable to diamond, and superhard boron subnitride B13N2. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc. are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure–temperature conditions are considered.

  3. Underground storage systems for high-pressure air and gases (United States)

    Beam, B. H.; Giovannetti, A.


    This paper is a discussion of the safety and cost of underground high-pressure air and gas storage systems based on recent experience with a high-pressure air system installed at Moffett Field, California. The system described used threaded and coupled oil well casings installed vertically to a depth of 1200 ft. Maximum pressure was 3000 psi and capacity was 500,000 lb of air. A failure mode analysis is presented, and it is shown that underground storage offers advantages in avoiding catastrophic consequences from pressure vessel failure. Certain problems such as corrosion, fatigue, and electrolysis are discussed in terms of the economic life of such vessels. A cost analysis shows that where favorable drilling conditions exist, the cost of underground high-pressure storage is approximately one-quarter that of equivalent aboveground storage.

  4. High pressure common rail injection system modeling and control. (United States)

    Wang, H P; Zheng, D; Tian, Y


    In this paper modeling and common-rail pressure control of high pressure common rail injection system (HPCRIS) is presented. The proposed mathematical model of high pressure common rail injection system which contains three sub-systems: high pressure pump sub-model, common rail sub-model and injector sub-model is a relative complicated nonlinear system. The mathematical model is validated by the software Matlab and a virtual detailed simulation environment. For the considered HPCRIS, an effective model free controller which is called Extended State Observer - based intelligent Proportional Integral (ESO-based iPI) controller is designed. And this proposed method is composed mainly of the referred ESO observer, and a time delay estimation based iPI controller. Finally, to demonstrate the performances of the proposed controller, the proposed ESO-based iPI controller is compared with a conventional PID controller and ADRC. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  5. High Pressure Processing Technology and Equipment Evolution: A Review

    Directory of Open Access Journals (Sweden)

    Wael M. Elamin


    Full Text Available High pressure processing (HPP is an interesting non-thermal technology that involves the sterilization of food by the mean of ultra-high pressures, which lead to extending the shelf life of processed food, as well as maintaining nutritional value and quality of food products. The consumers’ increasing demand for this new products graped the interest of several already-existing high pressure equipment manufacturers around the globe. The successful of this technology encouraged them to enter the field of food processing and adjust their existing technologies to adapt to the new process. This review spots the major discoveries in HPP equipment history, describes the current applications of HHP in processing and provides comprehensive information about HPP equipment technology used in commercial and research applications. In addition, this paper presents the major manufacturers in HPP equipment industry around the world.

  6. The value of high-pressure hysterosalpingography with new cannula. (United States)

    Totani, R


    To achieve maximum dilatation of the Fallopian tubes so as to improve the pregnancy: non-pregnancy ratio of hysterosalpingography (HSG) treatment, a high-pressure injection technique was evaluated. For this purpose a disposable cannula and an adapted pair of tenacula were developed and a remote-control procedure using an auto-injector and an adapted pressure recorder was used to assure the safety of doctors and staff. 1780 cases who underwent 400 mmHg high-pressure HSG treatment were compared with 903 conventional HSG cases. Results indicated a higher pregnancy ratio for the high-pressure experimental group after treatment. In addition, it was found that side effects due to the use of disposable cannula and highly viscous water-soluble mediums developed for use in angiography were less common than for conventional materials.

  7. Ultra-high pressure water jet: Baseline report; Greenbook (chapter)

    Energy Technology Data Exchange (ETDEWEB)



    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky{trademark} pump feeds water to a lance that directs the high pressure water at the surface to be removed. The technologies being tested for concrete decontamination are targeted for alpha contamination. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  8. Confinement of hydrogen at high pressure in carbon nanotubes (United States)

    Lassila, David H [Aptos, CA; Bonner, Brian P [Livermore, CA


    A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

  9. A High-Pressure Phase Transition of Calcite-III (United States)

    Catalli, K. C.; Williams, Q.


    We document the presence of a high-pressure phase transition in metastable calcite-III using infrared spectroscopy. The post-calcite-III transition initiates at a pressure of 15.5 (±2) GPa, and is completed between 25 and 30 GPa. The transition is particularly apparent in the ν4-in-plane bending vibration of the carbonate group, in which two new peaks gradually supplant the doublet associated with calcite-III. Furthermore, both the ν3-asymmetric and ν1-symmetric stretches of the carbonate group in the high-pressure phase appear at considerably lower frequencies than the extrapolated positions of the corresponding calcite-III peaks. The geometry of the carbonate unit within the high-pressure phase is likely closer to trigonal symmetry than in the calcite-III structure, and the C-O bond is probably longer than in the lower pressure calcite-III phase.

  10. High-pressure injection injuries of the hand. (United States)

    Pai, C H; Wei, D C; Hou, S P


    The majority of high-pressure injection injuries can produce serious damage to the hand. Nevertheless, the injury may follow a relatively benign course if the injected substance possesses a less harmful nature. Treatment for these injuries requires immediate and aggressive surgery in most circumstances, but conservative treatment may be justified in certain instances. During a 4-year period, eight cases of high-pressure injection injury were encountered. The types of injected material were: four from paint, and one each from grease, water, benzene, and hydraulic oil. Time is an important factor regarding the results, while the types of injected material modify the clinical courses. It is advisable that the etiology of high-pressure injection injury should be established initially, and this factor be taken into consideration in choosing treatment options.

  11. Deformation Twinning of a Silver Nanocrystal under High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojing; Yang, Wenge; Harder, Ross; Sun, Yugang; Liu, Ming; Chu, Yong S.; Robinson, Ian K.; Mao, Ho-kwang


    Within a high-pressure environment, crystal deformation is controlled by complex processes such as dislocation motion, twinning, and phase transitions, which change materials' microscopic morphology and alter their properties. Understanding a crystal's response to external stress provides a unique opportunity for rational tailoring of its functionalities. It is very challenging to track the strain evolution and physical deformation from a single nanoscale crystal under high-pressure stress. Here, we report an in situ three-dimensional mapping of morphology and strain evolutions in a single-crystal silver nanocube within a high-pressure environment using the Bragg Coherent Diffractive Imaging (CDI) method. We observed a continuous lattice distortion, followed by a deformation twining process at a constant pressure. The ability to visualize stress-introduced deformation of nanocrystals with high spatial resolution and prominent strain sensitivity provides an important route for interpreting and engineering novel properties of nanomaterials.

  12. Deformation Twinning of a Silver Nanocrystal under High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojing; Yang, Wenge; Harder, Ross; Sun, Yugang; Lu, Ming; Chu, Yong S.; Robinson, Ian K.; Mao, Ho-kwang


    Within a high-pressure environment, crystal deformation is controlled by complex processes such as dislocation motion, twinning, and phase transitions, which change materials’ microscopic morphology and alter their properties. Understanding a crystal’s response to external stress provides a unique opportunity for rational tailoring of its functionalities. It is very challenging to track the strain evolution and physical deformation from a single nanoscale crystal under high-pressure stress. Here, we report an in situ three-dimensional mapping of morphology and strain evolutions in a single-crystal silver nanocube within a high-pressure environment using the Bragg Coherent Diffractive Imaging (CDI) method. We observed a continuous lattice distortion, followed by a deformation twining process at a constant pressure. The ability to visualize stress-introduced deformation of nanocrystals with high spatial resolution and prominent strain sensitivity provides an important route for interpreting and engineering novel properties of nanomaterials.

  13. Accessing Mefenamic Acid Form II through High-Pressure Recrystallisation

    Directory of Open Access Journals (Sweden)

    Nasir Abbas


    Full Text Available High-pressure crystallisation has been successfully used as an alternative technique to prepare Form II of a non-steroidal anti-inflammatory drug, mefenamic acid (MA. A single crystal of Form II, denoted as high-pressure Form II, was grown at 0.3 GPa from an ethanolic solution by using a diamond anvil cell. A comparison of the crystal structures shows that the efficient packing of molecules in Form II was enabled by the structural flexibility of MA molecules. Compression studies performed on a single crystal of Form I resulted in a 14% decrease of unit cell volume up to 2.5 GPa. No phase transition was observed up to this pressure. A reconstructive phase transition is required to induce conformational changes in the structure, which was confirmed by the results of crystallisation at high pressure.

  14. Universality of the shear viscosity of alkali metals (United States)

    Meyer, N.; Xu, H.; Wax, J.-F.


    The universality of the shear viscosity of alkali metals is studied up to high pressure. Equilibrium molecular dynamics simulations are used to calculate the stress autocorrelation function, which allows us to obtain the value of shear viscosity using the Green-Kubo formula. Atomic interactions are computed from Fiolhais pseudopotential and are validated by comparison between pair distribution functions and mean-squared displacements obtained from classical and ab initio molecular dynamics simulations. The description of the interactions is accurate at least up to 12 GPa, 9.4 GPa, 6.6 GPa, and 3 GPa for Na, K, Rb, and Cs, respectively, and to a lesser extent up to 4.8 GPa for Li. A good agreement between simulation and experimental viscosity results along the liquid-gas coexistence curve is found. The viscosity appears to be a universal property over a wide range of the liquid phase of the phase diagram, between 0.85 and 1.5 times the ambient melting density and up to seven times the ambient melting temperature. Scaling laws are proposed following relations formulated in [Meyer, Xu, and Wax, Phys. Rev. B 93, 214203 (2016), 10.1103/PhysRevB.93.214203] so that it is possible to predict the viscosity value of any alkali metal with an accuracy better than 10% over the corresponding density and temperature range.

  15. Diffusion behavior of the fluorescent proteins eGFP and Dreiklang in solvents of different viscosity monitored by fluorescence correlation spectroscopy (United States)

    Junghans, Cornelia; Schmitt, Franz-Josef; Vukojević, Vladana; Friedrich, Thomas


    Fluorescence correlation spectroscopy relies on temporal autocorrelation analysis of fluorescence intensity fluctuations that spontaneously arise in systems at equilibrium due to molecular motion and changes of state that cause changes in fluorescence, such as triplet state transition, photoisomerization and other photophysical transformations, to determine the rates of these processes. The stability of a fluorescent molecule against dark state conversion is of particular concern for chromophores intended to be used as reference tags for comparing diffusion processes on multiple time scales. In this work, we analyzed properties of two fluorescent proteins, the photoswitchable Dreiklang and its parental eGFP, in solvents of different viscosity to vary the diffusion time through the observation volume element by several orders of magnitude. In contrast to eGFP, Dreiklang undergoes a dark-state conversion on the time scale of tens to hundreds of microseconds under conditions of intense fluorescence excitation, which results in artificially shortened diffusion times if the diffusional motion through the observation volume is sufficiently slowed down. Such photophysical quenching processes have also been observed in FCS studies on other photoswitchable fluorescent proteins including Citrine, from which Dreiklang was derived by genetic engineering. This property readily explains the discrepancies observed previously between the diffusion times of eGFP- and Dreiklang-labeled plasma membrane protein complexes.

  16. Viscosity Meaurement Technique for Metal Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Ban, Heng [Utah State Univ., Logan, UT (United States). Mechanical and Aerospace Engineering; Kennedy, Rory [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Metallic fuels have exceptional transient behavior, excellent thermal conductivity, and a more straightforward reprocessing path, which does not separate out pure plutonium from the process stream. Fabrication of fuel containing minor actinides and rare earth (RE) elements for irradiation tests, for instance, U-20Pu-3Am-2Np-1.0RE-15Zr samples at the Idaho National Laboratory, is generally done by melt casting in an inert atmosphere. For the design of a casting system and further scale up development, computational modeling of the casting process is needed to provide information on melt flow and solidification for process optimization. Therefore, there is a need for melt viscosity data, the most important melt property that controls the melt flow. The goal of the project was to develop a measurement technique that uses fully sealed melt sample with no Americium vapor loss to determine the viscosity of metallic melts and at temperatures relevant to the casting process. The specific objectives of the project were to: develop mathematical models to establish the principle of the measurement method, design and build a viscosity measurement prototype system based on the established principle, and calibrate the system and quantify the uncertainty range. The result of the project indicates that the oscillation cup technique is applicable for melt viscosity measurement. Detailed mathematical models of innovative sample ampoule designs were developed to not only determine melt viscosity, but also melt density under certain designs. Measurement uncertainties were analyzed and quantified. The result of this project can be used as the initial step toward the eventual goal of establishing a viscosity measurement system for radioactive melts.

  17. Survey of High-Pressure Effects in Solids. (United States)


    Roe Nmiw 10M Finad Repas Contrat No. MDA97C-0U5 a neuabyDeftn Mdwa esch P r* Ape Arlington, Virginb 22209 The vie wW cn oncluions cotIn i kl dosmnut...the Gordon-Kim-Boyer scheme with our suggested modifications ; use of the exchange-correlation potential in the local-density approximation i such an...limitations at very high pressures. One modification that becomes necessary at high pressures is not to first determine the two-body interatomic

  18. Effects of High Pressure on Membrane Ion Binding and Transport. (United States)


    AD-AI16 015 CALIFORNIA UNIV BERKELEY DEPT OF PHYSIOLOGY- ANATOMY FIG 6/16 EFFECTS OF HIGH PRESSURE ON MEMBRANE ION BINDING AND TRANSPORT.(U) DEC 80 R...ION BIND.NG AID TPANSPOFT (N)014-7 1-C-0482) 1Fobert I. 1.. cey, Ph.D. a v] Da iel M. F zan, Ph.D. Department of Ph ,sioloy- Anatomy unriveorsity o...given to Tra"uble’s theory . C. Develonrment of a High Pressure Zton-Flow Realization of the goals outlined in this project lenends on the availa- bility

  19. Novel High Pressure Multi-Component Diffusion Cell


    Elma, Muthia; Massarotto, Paul; Rudolph, Victor


    A novel high pressure multi-component diffusion cell (HPMCDC) apparatus has been designed and built to measure single and binary gas diffusion, including co-current and counter-diffusion, from low to high pressures. The apparatus incorporates capability to investigate scale effects in solid coal specimens, up to 25 mm in diameter and 25 mm in thickness. Future experiments will be conducted to measure diffusion and counter-diffusion of CH4 and CO2 gases in solid coal, at various temperatures, ...

  20. Collision condition indicted by High Pressure Phases in a Chondrite (United States)

    Kato, Y.; Sekine, T.; Kayama, M.; Miyahara, M.; Yamaguchi, A.


    It has been generally recognized that there were many collisions during planetary accretion. Chondrites include the materials at the time of formation of the solar system. It is essential to unravel the shock history in meteorites and the parent planet in order to understand such collisional processes. In this study, we investigate a thin section of ordinary chondrite Y-790729 classified as L6 in which high-pressure minerals are found in the about 620-μm-wide shock vein. The mineralogical and chemical features give us detailed information to constrain the shock conditions. We have tried to constrain the P-T condition from the viewpoints of the mineral assemblage and cathodoluminescense (CL) spectroscopy. Y-790729 consists mostly of olivine and pyroxene and has shock veins. To identify high pressure phases, we used an optical microscope, a scanning electron microscope (SEM), micro Raman spectroscopy, and electron probe micro analyzer (EPMA). In addition, scanning electron microscopy-cathodoluminescence (SEM-CL) analysis, detectable shock-induced defect centers, was used to characterize the shock metamorphism in feldspar minerals. The presence of shock vein, maskelynite, and high pressure phases confirms shock record. 7 high pressure phases of ringwoodite, high-pressure clinoenstatite (HPC), majorite, merrillite, lingunite, high-pressure chromite and akimotoite were found in this section. All of them exist only in a shock vein, but maskelynite occurs everywhere in the section. From these observations, it is obvious that the shock vein experienced the high pressure and high temperature generated by shock wave. If some of the high pressure minerals are equilibrated, the P-T condition can be estimated. Based on the equilibrium phase diagram of MgSiO3 polymorphs (Presnall. 1995), the P-T conditions for crystallization of majorite, HPC and akimotoite is about 17 GPa and 1600 oC, because the compositions of the three phases are close to MgSiO3. It is consistent with the

  1. Textural perception of liquid emulsions: Role of oil content, oil viscosity and emulsion viscosity

    NARCIS (Netherlands)

    Aken, van G.A.; Vingerhoeds, M.H.; Wijk, de R.A.


    This work describes a study on the in-mouth textural perception of thickened liquid oil-in-water emulsions. The variables studied are oil content, oil viscosity, and the concentration of polysaccharide thickener. Gum arabic was chosen as the thickener because of the nearly Newtonian behavior of its

  2. High-pressure behavior of NaInSi2O6 and the influence of Me3+ on the compressibility of NaMe3+Si2O6 silicates

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Nestola, F.; Balic Zunic, Tonci


    -anvil cell with diamond backing plates. The main structural compression mechanism is played by the tetrahedral chain kinking, which is related to the shortening of Na–O3long distances. Comparing our equation of state and high-pressure crystal structural results with previous data on NaMe3+Si2O6 pyroxenes, we...

  3. Ultra-high pressure water jet: Baseline report

    Energy Technology Data Exchange (ETDEWEB)



    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky{trademark} pump feeds water to a lance that directs the high pressure water at the surface to be removed. The safety and health evaluation during the testing demonstration focused on two main areas of exposure. These were dust and noise. The dust exposure was found to be minimal, which would be expected due to the wet environment inherent in the technology, but noise exposure was at a significant level. Further testing for noise is recommended because of the outdoor environment where the testing demonstration took place. In addition, other areas of concern found were arm-hand vibration, ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, fall hazards, slipping hazards, hazards associated with the high pressure water, and hazards associated with air pressure systems.

  4. High-pressure physical properties of magnesium silicate post ...

    Indian Academy of Sciences (India)

    dLaboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Academy of Engineering. Physics, PO Box 919-102, Mianyang 621900, China. MS received 1 May 2011. Abstract. The structure, thermodynamic and elastic properties of magnesium silicate (MgSiO3) post-perovskite at high pressure ...

  5. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  6. Numerical investigation of high pressure condensing flows in supersonic nozzles

    NARCIS (Netherlands)

    Azzini, L.; Pini, M.


    High-pressure non-equilibrium condensing flows are investigated in this paper through a quasi-1D Euler model coupled to the method of moments for the physical characterization of the dispersed phase. Two different numerical approaches, namely the so-called (a) the mixture and (b) continuum phase

  7. Structural properties of BeO at high pressure

    Indian Academy of Sciences (India)


    nuclear reactor (Zeezherun et al 1963). BeO has the wurzite structure (B4) under ambient condition, although the other BeX (X = S, Se and Te) crystallizes in zinc blend (B3). In recent past, phase transition at high pressure has been a subject of great interest for experi- mentalists as well as theoreticians. Recently, Yashihisa.

  8. Screening of hydrogen storage media applying high pressure thermogravimetry

    DEFF Research Database (Denmark)

    Bentzen, J.J.; Pedersen, Allan Schrøder; Kjøller, J.


    A number of commercially available hydride-forming alloys of the MmNi5–xSnx (Mm=mischmetal, a mixture of lanthanides) type were examined using a high pressure, high temperature microbalance,scanning electron microscopy and X-ray diffraction. Activation conditions, reversible storage capacity, wor...

  9. Pneumomediastinum following high pressure air injection to the hand.

    LENUS (Irish Health Repository)

    Kennedy, J


    We present the case of a patient who developed pneumomediastinum after high pressure air injection to the hand. To our knowledge this is the first reported case of pneumomediastinum where the gas injection site was the thenar eminence. Fortunately the patient recovered with conservative management.

  10. Pneumomediastinum following high pressure air injection to the hand.

    LENUS (Irish Health Repository)

    Kennedy, J


    We present the case of a patient who developed pneumomediastinum after high pressure air injection to the hand. To our knowledge this is the first reported case of pneumomediastinum where the gas injection site was the thenar eminence. Fortunately the patient recovered with conservative management.

  11. High pressure injection injuries: a serious occupational hazard. (United States)

    Mrvos, R; Dean, B S; Krenzelok, E P


    High pressure injection equipment such as airless paint sprayers, high pressure grease guns, and fuel injection apparatus constitute a serious safety hazard resulting in significant morbidity. These devices are capable of delivering contaminants such as paint, solvents, and grease at pressures ranging from 600-12,000 psi. This allows the substance to penetrate through a minute skin wound and to spread widely through fascial planes and tendon sheaths and to produce significant vascular compression and systemic toxicity. High pressure injection injuries frequently result in amputation. Fifty-five suspected high pressure injection injury cases were evaluated. Twenty were determined to be actual injection injuries from equipment producing pressures in the range of 1,500-12,000 psi. The injected contaminants included latex paint, mineral spirits, and concrete sealer. Fourteen injuries involved digits. Digital amputation was necessary in three patients. Hospital admissions averaged 6.5 days. Successful management of these cases involves awareness of the impending problem and rapid referral of the patient to an emergency department and to a competent orthopedic or plastic surgeon.

  12. Propane Oxidation at High Pressure and Intermediate Temperatures

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Glarborg, Peter

    Propane oxidation at intermediate temperatures (500—900 K) and high pressure (100 bar) has been characterized by conducting experiments in a laminar flow reactor over a wide range of stoichiometries. The onset of fuel oxidation was found to be 600—725 K, depending on mixture stoichiometry...

  13. High pressure gas laser technology for atmospheric remote sensing (United States)

    Javan, A.


    The development of a fixed frequency chirp-free and highly stable intense pulsed laser made for Doppler wind velocity measurements with accurate ranging is described. Energy extraction from a high pressure CO2 laser at a tunable single mode frequency is also examined.

  14. Performance studies on high pressure 1-D position sensitive ...

    Indian Academy of Sciences (India)

    Performance studies on high pressure 1-D position sensitive neutron detectors. S S DESAI and A M SHAIKH∗. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. *Corresponding author. E-mail: Abstract. The powder diffractometer and Hi-Q diffractometer at ...

  15. High-pressure applications in medicine and pharmacology (United States)

    Silva, Jerson L.; Foguel, Debora; Suarez, Marisa; Gomes, Andre M. O.; Oliveira, Andréa C.


    High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic.

  16. Raman Studies of Vanadates at Low Temperatures and High Pressures

    NARCIS (Netherlands)

    Siranidi, E.; Lampakis, D.; Palles, D.; Liarokapis, E.; Colin, C.; Palstra, T. T. M.

    The spin and orbital ordering have been examined for high-quality SmVO(3) polycrystalline compound using Raman spectroscopy. Measurements were obtained on individual microcrystallites in the approximate y(zz)y and y(xx)y scattering configurations at low temperatures (down to 20 K) and high pressures

  17. High-pressure deformation and failure of polycrystalline ceramics (United States)

    Zhang, Dongmei


    High-strength polycrystalline ceramics are increasingly being used for armor applications because of their light weight and superior ballistic performance over conventional armor steels. However, accurate material modeling needed in ceramic armor design remains a challenge because of their complex behavior under impact loading. A ceramic may display extremely high strength during rapid compression but lose tensile strength when the load reverses from compression to tension. A good understanding of the mechanisms governing the deformation and failure of ceramics under high-stress impact and a capability to accurately predict the resulting effective strengths of both intact and damaged ceramics are critically needed. To this end, a computational methodology for micromechanical analysis of polycrystalline materials has been developed. It combines finite element analysis with microstructural modeling based on the Voronoi polycrystals, and material modeling that considers nonlinear elasticity, crystal plasticity, intergranular shear damage during compression and intergranular Mode-I cracking during tension. Using this method, simulations have been carried out on polycrystalline alpha-6H silicon carbide and alpha-phase aluminum oxide to determine if microplasticity is a viable mechanism of inelastic deformation in ceramics undergoing high-pressure uniaxial-strain compression. Further, the competing roles of in-grain microplasticity and intergranular microdamage during a sequence of dynamic compression and tension have been studied. The results show that microplasticity is a more plausible mechanism than microcracking under uniaxial-strain compression. The deformation by limited slip systems can be highly heterogeneous so that a significant amount of grains may remain elastic and thus result in high macroscopic compressive strength. On the other hand, the failure evolution during dynamic load reversal from compression to tension can be well predicted by intergranular Mode

  18. High pressure electrical conductivity in naturally occurring silicate liquids (United States)

    Tyburczy, James A.; Waff, Harve S.

    Electrical conductivities of molten Hawaiian rhyodacite and Yellowstone rhyolite obsidian were measured between 1200° C and 1400° C and at pressures up to 25 kilobars. The two melts exhibit similar trends. Arrhenius behavior is observed at all pressures studied. Isobaric activation enthalpies increase from about 0.5 eV at atmospheric pressure to about 0.9 eV at 25 kbars, and the magnitude of the conductivity decreases by about a factor of 4 between 0 and 25 kbar. At pressures between about 10 and 15 kbar an abrupt decrease in the slopes of isothermal log a versus pressure plots is observed. In each pressure range an equation of the form σ = σ'0 exp [- (E'σ + PΔV'σ)/kT], where σ'0, E'σ, and ΔV'σ, are constants, describes the polybaric, polythermal data. Comparison of these data with high pressure electrical conductivities of molten basalt and andesite reveals that relatively silica-rich melts, from andesitic to rhyolitic in composition, display similar trends, while the basaltic melt has analogous, but quantitatively different trends. Comparison of zero-pressure electrical conductivity and sodium diffusivity by means of the Nernst-Einstein relation indicates that sodium ion transport is the dominant mechanism of charge transport in the obsidian melt at zero pressure. The tholeiitic melt, on the other hand, displays only order of magnitude agreement between the electrical conductivity and sodium diffusivity, indicating that either ions other than sodium play a significant role in electrical transport or that the motions of the sodium ions are strongly correlated, or both. Comparison of the isobaric and isochoric activation enthalpies indicates that electrical conduction is energy restrained, as opposed to volume restrained. Conductivities in the andesitic, rhyodacitic, and rhyolitic melts conform to a single compensation law line, with no indication of the change in activation volume. The tholeiitic melt has a slightly different compensation line. In light

  19. Direct measurement of gas solubilities in polymers with a high-pressure microbalance

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Nielsen, Johannes Kristoffer; Hassager, Ole


    Solubility and diffusion data are presented for methane and carbon dioxide gases in high-density polyethylene. The polymer was cut from extruded piping intended for use in offshore oil and gas applications. The measurements were carried out with a high-pressure microbalance. The properties were...... determined from 25 to 50degreesC and from 50 to 150 bar for methane and from 20 to 40 bar for carbon dioxide. In general, a good agreement was obtained with similar measurements reported in the literature. The solubility followed Henry's law (linear) dependence with pressure, except at high pressures...... for methane, for which negative deviations from Henry's law behavior were observed. The diffusion coefficients for each of the gases in the polymer were also measured with the balance, although the uncertainty was greater than for the solubility measurements. (C) 2003 Wiley Periodicals, Inc. J Appl Polyrn Sci...

  20. High-pressure vapor-liquid equilibrium data for CO2-orange peel oil

    Directory of Open Access Journals (Sweden)

    G.R. Stuart


    Full Text Available Recently, there has been a growing interest in fractionating orange peel oil by the use of supercritical carbon dioxide (SCCO2. However, progress in this area has been hindered by the lack of more comprehensive work concerning the phase equilibrium behavior of the SCCO2-orange peel oil system. In this context, the aim of this work is to provide new phase equilibrium data for this system over a wide range of temperatures and pressures, permitting the construction of coexistence PT-xy curves as well as the P-T diagram. The experiments were performed in a high-pressure variable-volume view cell in the temperature range of 50-70ºC from 70 to 135 atm and in the CO2 mass fraction composition range of 0.35-0.98. Based on the experimental phase equilibrium results, appropriate operating conditions can be set for high-pressure fractionation purposes.

  1. Effects of high pressure on azobenzene and hydrazobenzene probed by Raman spectroscopy. (United States)

    Dong, Zhaohui; Seemann, Natashia M; Lu, Ning; Song, Yang


    In this study, two hydrazine derivatives, azobenzene and hydrazobenzene, were compressed in a diamond anvil cell at room temperature up to 28 GPa followed by decompression. In situ Raman spectroscopy was employed to monitor the pressure-induced structural evolutions. Azobenzene was found to undergo a phase transition at ~10 GPa. Further compression to 18 GPa resulted in an irreversible breakdown of the molecular structure. Although hydrazobenzene exhibited a structural transition at a similar pressure of 10 GPa, it was found to sustain a compression pressure as high as 28 GPa without chemical reactions. The transition sequence of hydrazobenzene upon compression and decompression was thus entirely reversible in the pressure region studied, in strong contrast to that of azobenzene. The high-pressure structures of these two molecules were examined based on the spectroscopic data, and their drastically different high-pressure behaviors were analyzed and interpreted with the aid of ab initio molecular orbital calculations.

  2. Modeling and simulation of high-pressure industrial autoclave polyethylene reactor

    Directory of Open Access Journals (Sweden)


    Full Text Available High-pressure technology for polyethylene production has been widely used by industries around the world. A good model for the reactor fluid dynamics is essential to set the operating conditions of an autoclave reactor. The high-pressure autoclave reactor model developed in this work was based on a non-isothermal dynamic model, where PID control equations are used to maintain the operation at the unstable steady state. The kinetic mechanism to describe the polymerization rate and molecular weight averages are presented. The model is capable of computing temperature, concentration gradients and polymer characteristics. The model was validated for an existing industrial reactor and data for production of homopolymer polyethylene and has represented well the behavior of the autoclave reactor used in ethylene homopolymerization.

  3. Effect of moderate inlet temperatures in ultra-high-pressure homogenization treatments on physicochemical and sensory characteristics of milk. (United States)

    Amador-Espejo, G G; Suàrez-Berencia, A; Juan, B; Bárcenas, M E; Trujillo, A J


    The effect of ultra-high-pressure homogenization (UHPH) on raw whole milk (3.5% fat) was evaluated to obtain processing conditions for the sterilization of milk. Ultra-high-pressure homogenization treatments of 200 and 300 MPa at inlet temperatures (Ti) of 55, 65, 75, and 85 °C were compared with a UHT treatment (138 °C for 4s) in terms of microbial inactivation, particle size and microstructure, viscosity, color, buffering capacity, ethanol stability, propensity to proteolysis, and sensory evaluation. The UHPH-treated milks presented a high level of microbial reduction, under the detection limit, for treatments at 300 MPa with Ti of 55, 65, 75, and 85 °C, and at 200 MPa with Ti = 85 °C, and few survivors in milks treated at 200 MPa with Ti of 55, 65, and 75 °C. Furthermore, UHPH treatments performed at 300 MPa with Ti = 75 and 85 °C produced sterile milk after sample incubation (30 and 45 °C), obtaining similar or better characteristics than UHT milk in color, particle size, viscosity, buffer capacity, ethanol stability, propensity to protein hydrolysis, and lower scores in sensory evaluation for cooked flavor. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Experiments on aerosol removal by high-pressure water spray

    Energy Technology Data Exchange (ETDEWEB)

    Corno, Ada del, E-mail: [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)


    Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 3}. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 3}. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was

  5. Pressure Effect on Extensional Viscosity

    DEFF Research Database (Denmark)

    Christensen, Jens Horslund; Kjær, Erik Michael


    The primary object of these experiments was to investigate the influence of hydrostatic pressure on entrance flow. The effect of pressure on shear and extensional viscosity was evaluated using an axis symmetric capillary and a slit die where the hydrostatic pressure was raised with valves....... The experiments show a significant increase in extensional viscosity with increasing pressure....

  6. Chebyshev super spectral viscosity method for water hammer analysis

    Directory of Open Access Journals (Sweden)

    Hongyu Chen


    Full Text Available In this paper, a new fast and efficient algorithm, Chebyshev super spectral viscosity (SSV method, is introduced to solve the water hammer equations. Compared with standard spectral method, the method's advantage essentially consists in adding a super spectral viscosity to the equations for the high wave numbers of the numerical solution. It can stabilize the numerical oscillation (Gibbs phenomenon and improve the computational efficiency while discontinuities appear in the solution. Results obtained from the Chebyshev super spectral viscosity method exhibit greater consistency with conventional water hammer calculations. It shows that this new numerical method offers an alternative way to investigate the behavior of the water hammer in propellant pipelines.

  7. Volatiles Which Increase Magma Viscosity (United States)

    Webb, S.


    The standard model of an erupting volcano is one in which the viscosity of a decompressing magma increases as the volatiles leave the melt structure to form bubbles. It has now been observed that the addition of the "volatiles" P, Cl and F result in an increase in silicate melt viscosity. This observation would mean that the viscosity of selected degassing magmas would decrease rather than increase. Here we look at P, Cl and F as three volatiles which increase viscosity through different structural mechanisms. In all three cases the volatiles increase the viscosity of peralkaline composition melts, but appear to always decrease the viscosity of peraluminous melts. Phosphorus causes the melt to unmix into a Na-P rich phase and a Na-poor silicate phase. Thus as the network modifying Na (or Ca) are removed to the phosphorus-rich melt, the matrix melt viscosity increases. With increasing amounts of added phosphorus (at network modifying Na ~ P) the addition of further phosphorus causes a decrease in viscosity. The addition of chlorine to Fe-free aluminosilicate melts results in an increase in viscosity. NMR data on these glass indicates that the chlorine sits in salt-like structures surrounded by Na and/or Ca. Such structures would remove network-modifying atoms from the melt structure and thus result in an increase in viscosity. The NMR spectra of fluorine-bearing glasses shows that F takes up at least 5 different structural positions in peralkaline composition melts. Three of these positions should result in a decrease in viscosity due to the removal of bridging oxygens. Two of the structural positons of F, however, should result in an increase in viscosity as they require the removal of network-modifying atoms from the melt structure (with one of the structures being that observed for Cl). This would imply that increasing amounts of F might result in an increase in viscosity. This proposed increase in viscosity with increasing F has now been experimentally confirmed.

  8. The viscosity of dimethyl ether

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, Jørgen


    and NOx traps are installed. The most significant problem encountered when engines are fuelled with DME is that the injection equipment breaks down prematurely due to extensive wear. This tribology issue can be explained by the very low lubricity and viscosity of DME. Recently, laboratory methods have...... appeared capable of measuring these properties of DME. The development of this is rendered difficult because DME has to be pressurised to remain in the liquid state and it dissolves most of the commercially available elastomers. This paper deals fundamentally with the measurement of the viscosity of DME...... and extends the discussion to the difficulty of viscosity establishing of very thin fluids. The main issue here is that it is not easy to calibrate the viscometers in the very low viscosity range corresponding to about one-fifth of that of water. The result is that the low viscosity is measured at high...

  9. Capillary waves with surface viscosity (United States)

    Shen, Li; Denner, Fabian; Morgan, Neal; van Wachem, Berend; Dini, Daniele


    Experiments over the last 50 years have suggested a correlation between the surface (shear) viscosity and the stability of a foam or emulsion. With recent techniques allowing more accurate measurements of the elusive surface viscosity, we examine this link theoretically using small-amplitude capillary waves in the presence of the Marangoni effect and surface viscosity modelled via the Boussinesq-Scriven model. The surface viscosity effect is found to contribute a damping effect on the amplitude of the capillary wave with subtle differences to the effect of the convective-diffusive Marangoni transport. The general wave dispersion is augmented to take into account the Marangoni and surface viscosity effects, and a first-order correction to the critical damping wavelength is derived. The authors acknowledge the financial support of the Shell University Technology Centre for fuels and lubricants.

  10. Shock Recovery of the High Pressure Phase Bismuth III (United States)

    Fussell, Zachary; Tschauner, Oliver; Hawkins, Cameron; Ma, Chi; Smith, Jesse; Advanced Photon Source Team; California Institution of Technology Team; National Security Technologies Team; University of Nevada, Las Vegas Team


    Between 0 and 10 GPa there are five different bismuth phases. High-pressure bismuth (Bi) phases have been examined in static compression experiments; however, none could be recovered to ambient conditions. Here we report Bi-III recovery (stable above 3 GPa) to ambient conditions from a shock compression experiment to 5.7 GPa. Bi-III was identified by synchrotron micro-diffraction and backscatter electron imaging. Our work shows shock-compression provides a tool for recovering high-pressure phases that otherwise elude decompression. This work supported by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy and by the Site-Directed Research and Development Program. DOE/NV/25946-3070.

  11. Equation of state of liquid Indium under high pressure

    Directory of Open Access Journals (Sweden)

    Huaming Li


    Full Text Available We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.

  12. Introduction to high-pressure bioscience and biotechnology. (United States)

    Bartlett, Douglas H


    The manipulation of biological materials using elevated pressure is providing an ever-growing number of opportunities in both the applied and basic sciences. Manipulation of pressure is a useful parameter for enhancing food quality and shelf life; inactivating microbes, viruses, prions, and deleterious enzymes; affecting recombinant protein production; controlling DNA hybridization; and improving vaccine preparation. In biophysics and biochemistry, pressure is used as a tool to study intermediates in protein folding, enzyme kinetics, macromolecular interactions, amyloid fibrous protein aggregation, lipid structural changes, and to discern the role of solvation and void volumes in these processes. Biologists, including many microbiologists, examine the utility and basis of pressure inactivation of cells and cellular processes, and conversely seek to discover how deep-sea life has evolved a preference for high-pressure environments. This introduction and the papers that follow provide information on the nature and promise of the highly interdisciplinary field of high-pressure bioscience and biotechnology (HPBB).

  13. Miscible displacement by high-pressure gas at Block 31

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, J.H.; Robertson, N.


    The world's first large-scale miscible displacement project by high-pressure gas injection has produced 130,000,000 bbl, almost double the original estimated primary recovery of 69,000,000 bbl, at the University Block 31 field in Crane County, Texas. The field-wide project began in 1952, and will keep the unit on stream well into the future, with ultimate recovery efficiency estimated at 60%. Infill drilling has helped boost daily production to 16,000 bbl, highest producing rate since gas injection began in 1949. The subject discussed include reservoir characteristics, high pressure gas miscibility, flue gas generation, production problems, and new lift for an old field by infill drilling.

  14. Germination of vegetable seeds exposed to very high pressure (United States)

    Mori, Y.; Yokota, S.; Ono, F.


    Effects of high hydrostatic pressure were investigated on vegetable seeds in the GPa range to examine the potentialities of breed improvement by high-pressure processing. Specimens of several seeds of broccoli (Brassica oleracea var. italica), Turnip leaf (Brassica rapa var. perviridis) and Potherb Mustard (Brassica rapa var. nipposinica) were put in a teflon capsule with liquid high pressure medium, fluorinate, and inserted into a pyrophillite cube. By using a cubic anvil press a hydrostatic pressure of 5.5 GP a was applied to these seeds for 15 minutes. After being brought back to ambient pressure, they were seeded on humid soil in a plant pot. Many of these vegetable seeds began to germinate within 6 days after seeded.

  15. Phase diagram of Nitrogen at high pressures and temperatures (United States)

    Jenei, Zsolt; Lin, Jung-Fu; Yoo, Choong-Shik


    Nitrogen is a typical molecular solid with relatively weak van der Waals intermolecular interactions but strong intramolecular interaction arising from the second highest binding energy of all diatomic molecules. The phase diagram of solid nitrogen is, however, complicated at high pressures, as inter-molecular interaction becomes comparable to the intra-molecular interaction. In this paper, we present an updated phase diagram of the nitrogen in the pressure-temperature region of 100 GPa and 1000 K, based on in-situ Raman and synchrotron x-ray diffraction studies using externally heated membrane diamond anvil cells. While providing an extension of the phase diagram, our results indicate a ``steeper'' slope of the δ/ɛ phase boundary than previously determined^1. We also studied the stability of the ɛ phase at high pressures and temperatures. Our new experimental results improve the understanding of the Nitrogen phase diagram. 1. Gregoryanz et al, Phys. Rev. B 66, 224108 (2002)

  16. The effect of high pressure on nitrogen compounds of milk

    Energy Technology Data Exchange (ETDEWEB)

    Kielczewska, Katarzyna [Institute of Dairy Science and Technology Development, Warmia and Masuria University in Olsztyn, Hevelius 1 Street, 10-957 Olsztyn (Poland); Czerniewicz, Maria [Institute of Dairy Science and Technology Development, Warmia and Masuria University in Olsztyn, Hevelius 1 Street, 10-957 Olsztyn (Poland); Michalak, Joanna [Chair of Instrumental Analysis, Warmia and Masuria University in Olsztyn, Hevelius 1 Street, 10-957 Olsztyn (Poland); Brandt, Waldemar [Institute of Dairy Science and Technology Development, Warmia and Masuria University in Olsztyn, Hevelius 1 Street, 10-957 Olsztyn (Poland)


    The effect of pressurization at different pressures (from 200 to 1000 MPa, at 200 MPa intervals, t{sub const.} = 15 min) and periods of time (from 15 to 35 min, at 10 min intervals, p{sub const.} = 800 MPa) on the changes of proteins and nitrogen compounds of skimmed milk was studied. The pressurization caused an increase in the amount of soluble casein and denaturation of whey proteins. The level of nonprotein nitrogen compounds and proteoso-peptone nitrogen compounds increased as a result of the high-pressure treatment. These changes increased with an increase in pressure and exposure time. High-pressure treatment considerably affected the changes in the conformation of milk proteins, which was reflected in the changes in the content of proteins sedimenting and an increase in their degree of hydration.

  17. Leak Detection of High Pressure Feedwater Heater Using Empirical Models

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Song Kyu; Kim, Eun Kee [Korea Power Engineering Company, Daejeon (Korea, Republic of); Heo, Gyun Young [Kyung Hee University, Yongin (Korea, Republic of); An, Sang Ha [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)


    Even small leak from tube side or pass partition within the high pressure feedwater heater (HPFWH) causes a significant deficiency in its performance. Plant operation under the HPFWH leak condition for long time will result in cost increase. Tube side leak within HPFWH can produce the high velocity jet of water and it can cause neighboring tube failures. However, most of plants are being operated without any information for internal leaks of HPFWH, even though it is prone to be damaged under high temperature and high pressure operating conditions. Leaks from tubes and/or pass partition of HPFWH occurred in many nuclear power plants, for example, Mihama PS-2, Takahama PS-2 and Point Beach Nuclear Plant Unit 1. If the internal leaks of HPFWH are monitored, the cost can be reduced by inexpensive repairs relative to loss in performance and moreover plant shutdown as well as further tube damages can be prevented.

  18. Industrial high pressure applications. Processes, equipment and safety

    Energy Technology Data Exchange (ETDEWEB)

    Eggers, Rudolf (ed.) [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Inst. fuer Thermische Verfahrenstechnik


    Industrial high pressure processes open the door to many reactions that are not possible under 'normal' conditions. These are to be found in such different areas as polymerization, catalytic reactions, separations, oil and gas recovery, food processing, biocatalysis and more. The most famous high pressure process is the so-called Haber-Bosch process used for fertilizers and which was awarded a Nobel prize. Following an introduction on historical development, the current state, and future trends, this timely and comprehensive publication goes on to describe different industrial processes, including methanol and other catalytic syntheses, polymerization and renewable energy processes, before covering safety and equipment issues. With its excellent choice of industrial contributions, this handbook offers high quality information not found elsewhere, making it invaluable reading for a broad and interdisciplinary audience.

  19. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure (United States)

    Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.


    Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

  20. High pressure extraction of phenolic compounds from citrus peels† (United States)

    Casquete, R.; Castro, S. M.; Villalobos, M. C.; Serradilla, M. J.; Queirós, R. P.; Saraiva, J. A.; Córdoba, M. G.; Teixeira, P.


    This study evaluated the effect of high pressure processing on the recovery of high added value compounds from citrus peels. Overall, the total phenolic content in orange peel was significantly (P < .05) higher than that in lemon peel, except when pressure treated at 500 MPa. However, lemon peel demonstrated more antioxidant activity than orange peel. Pressure-treated samples (300 MPa, 10 min; 500 MPa, 3 min) demonstrated higher phenolic content and antioxidant activity comparatively to the control samples. For more severe treatments (500 MPa, 10 min), the phenolic content and antioxidant activity decreased in both lemon and orange peels. This paper was presented at the 8th International Conference on High Pressure Bioscience & Biotechnology (HPBB 2014), in Nantes (France), 15-18 July 2014.

  1. Chemical Vapor Deposition at High Pressure in a Microgravity Environment (United States)

    McCall, Sonya; Bachmann, Klaus; LeSure, Stacie; Sukidi, Nkadi; Wang, Fuchao


    In this paper we present an evaluation of critical requirements of organometallic chemical vapor deposition (OMCVD) at elevated pressure for a channel flow reactor in a microgravity environment. The objective of using high pressure is to maintain single-phase surface composition for materials that have high thermal decomposition pressure at their optimum growth temperature. Access to microgravity is needed to maintain conditions of laminar flow, which is essential for process analysis. Based on ground based observations we present an optimized reactor design for OMCVD at high pressure and reduced gravity. Also, we discuss non-intrusive real-time optical monitoring of flow dynamics coupled to homogeneous gas phase reactions, transport and surface processes. While suborbital flights may suffice for studies of initial stages of heteroepitaxy experiments in space are essential for a complete evaluation of steady-state growth.

  2. Volume analysis of supercooled water under high pressure


    Duki, Solomon F.; Tsige, Mesfin


    Motivated by recent experimental findings on the volume of supercooled water at high pressure [O. Mishima, J. Chem. Phys. 133, 144503 (2010)] we performed atomistic molecular dynamics simulations study of bulk water in the isothermal-isobaric ensemble. Cooling and heating cycles at different isobars and isothermal compression at different temperatures are performed on the water sample with pressures that range from 0 to 1.0 GPa. The cooling simulations are done at temperatures that range from...

  3. Simulation of plasma loading of high-pressure RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kwangmin [Brookhaven; Samulyak, Roman [SUNY, Stony Brook; Yonehara, Katsuya [Fermilab; Freemire, Ben [Northern Illinois U.


    Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have been performed in the range of parameters typical for practical muon cooling channels.

  4. High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

    Directory of Open Access Journals (Sweden)

    R.F. Vogel


    Full Text Available Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2- to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK, while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

  5. Ammonia oxidation at high pressure and intermediate temperatures

    DEFF Research Database (Denmark)

    Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt


    was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3⟶+OH NH2⟶+HO2,NO2 H2NO⟶+O2 HNO⟶+O2 NO ⟶+NH2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH...

  6. Effect of High Pressure and Heat on Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Dirk Margosch


    Full Text Available Even though the inactivation of microorganisms by high pressure treatment is a subject of intense investigations, the effect of high pressure on bacterial toxins has not been studied so far. In this study, the influence of combined pressure/temperature treatment (0.1 to 800 MPa and 5 to 121 °C on bacterial enterotoxins was determined. Therefore, heat-stable enterotoxin (STa of cholera toxin (CT from Vibrio cholerae, staphylococcal enterotoxins A-E, haemolysin BL (HBL from Bacillus cereus, and Escherichia coli (STa were subjected to different treatment schemes. Structural alterations were monitored in enzyme immunoassays (EIAs. Cytotoxicity of the pressure treated supernatant of toxigenic B. cereus DSM 4384 was investigated with Vero cells. High pressure of 200 to 800 MPa at 5 °C leads to a slight increase of the reactivity of the STa of E. coli. However, reactivity decreased at 800 MPa and 80 °C to (66±21 % after 30 min and to (44±0.3 % after 128 min. At ambient pressure no decrease in EIA reactivity could be observed after 128 min. Pressurization (0.1 to 800 MPa of heat stable monomeric staphylococcal toxins at 5 and 20 °C showed no effect. A combined heat (80 °C and pressure (0.1 to 800 MPa treatment lead to a decrease in the immuno-reactivity to 20 % of its maximum. For cholera toxin a significant loss in latex agglutination was observable only at 80 °C and 800 MPa for holding times higher than 20 min. Interestingly, the immuno-reactivity of B. cereus HBL toxin increased with the increase of pressure (182 % at 800 MPa, 30 °C, and high pressure showed only minor effects on cytotoxicity to Vero cells. Our results indicate that pressurization can increase inactivation observed by heat treatment, and combined treatments may be effective at lower temperatures and/or shorter incubation time.

  7. High-pressure phase transition and properties of spinel ZnMn2O4

    DEFF Research Database (Denmark)

    Åbrink, S.; Waskowska, A.; Gerward, Leif


    to normal pressure. The c/a ratio reduces from 1.62 to 1.10 above P-c and remains nearly pressure independent in the high-pressure phase. The transition is attributed to the changes in electron configuration of the Mn3+ ions. According to the crystal field theory, the e(g) electron of octahedrally......-pressure behavior of ZnMn2O4 was investigated up to 52 GPa using the energy-dispersive x-ray diffraction technique and synchrotron radiation. The structural first-order phase transition from the body-centered to primitive-tetragonal cell takes place at P-c = 23 GPa. The high-pressure phase is metastable down...... coordinated Mn3+ is either in the d(z)(2) orbital or in the d(x2-y2). In the first configuration the MnO6 octahedron will be elongated and this is the case at normal pressure, while the second configuration gives the flattened octahedron. In the high-pressure phase some proportion of the e(g) electrons...

  8. Synthesis and stability of hydrogen selenide compounds at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Pace, Edward J.; Binns, Jack; Alvarez, Miriam Pena; Dalladay-Simpson, Philip; Gregoryanz, Eugene; Howie, Ross T. (Edinburgh); (CHPSTAR- China)


    The observation of high-temperature superconductivity in hydride sulfide (H2S) at high pressures has generated considerable interest in compressed hydrogen-rich compounds. High-pressure hydrogen selenide (H2Se) has also been predicted to be superconducting at high temperatures; however, its behaviour and stability upon compression remains unknown. In this study, we synthesize H2Se in situ from elemental Se and molecular H2 at pressures of 0.4 GPa and temperatures of 473 K. On compression at 300 K, we observe the high-pressure solid phase sequence (I-I'-IV) of H2Se through Raman spectroscopy and x-ray diffraction measurements, before dissociation into its constituent elements. Through the compression of H2Se in H2 media, we also observe the formation of a host-guest structure, (H2Se)2H2, which is stable at the same conditions as H2Se, with respect to decomposition. These measurements show that the behaviour of H2Se is remarkably similar to that of H2S and provides further understanding of the hydrogen chalcogenides under pressure.

  9. High pressure synthesis of amorphous TiO2 nanotubes

    Directory of Open Access Journals (Sweden)

    Quanjun Li


    Full Text Available Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM study. In addition, the bulk modulus (B0 = 158 GPa of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa. We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.

  10. A subdivision algorithm for phase equilibrium calculations at high pressures

    Directory of Open Access Journals (Sweden)

    M. L. Corazza


    Full Text Available Phase equilibrium calculations at high pressures have been a continuous challenge for scientists and engineers. Traditionally, this task has been performed by solving a system of nonlinear algebraic equations originating from isofugacity equations. The reliability and accuracy of the solutions are strongly dependent on the initial guess, especially due to the fact that the phase equilibrium problems frequently have multiple roots. This work is focused on the application of a subdivision algorithm for thermodynamic calculations at high pressures. The subdivision algorithm consists in the application of successive subdivisions at a given initial interval (rectangle of variables and a systematic test to verify the existence of roots in each subinterval. If the interval checked passes in the test, then it is retained; otherwise it is discharged. The algorithm was applied for vapor-liquid, solid-fluid and solid-vapor-liquid equilibrium as well as for phase stability calculations for binary and multicomponent systems. The results show that the proposed algorithm was capable of finding all roots of all high-pressure thermodynamic problems investigated, independent of the initial guess used.

  11. Reinvestigation of high pressure polymorphism in hafnium metal

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, K. K., E-mail:; Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India); Gyanchandani, Jyoti; Dey, G. K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India); Somayazulu, M. [Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015 (United States); Sikka, S. K. [Indian National Science Academy, New Delhi-110 002 (India)


    There has been a recent controversy about the high pressure polymorphism of Hafnium (Hf). Unlike, the earlier known α→ω structural transition at 38 ± 8 GPa, at ambient temperature, Hrubiak et al. [J. Appl. Phys. 111, 112612 (2012)] did not observe it till 51 GPa. They observed this transition only at elevated temperatures. We have reinvestigated the room temperature phase diagram of Hf, employing x-ray diffraction (XRD) and DFT based first principles calculations. Experimental investigations have been carried out on several pure and impure Hf samples and also with different pressure transmitting media. Besides demonstrating the significant role of impurity levels on the high pressure phase diagram of Hf, our studies re-establish room temperature α→ω transition at high pressures, even in quasi-hydrostatic environment. We observed this transition in pure Hf with equilibrium transition pressure P{sub o} = 44.5 GPa; however, with large hysteresis. The structural sequence, transition pressures, the lattice parameters, the c/a ratio and its variation with compression for the α and ω phases as predicted by our ab-initio scalar relativistic (SR) calculations are found to be in good agreement with our experimental results of pure Hf.

  12. Elasticity of methane hydrate phases at high pressure. (United States)

    Beam, Jennifer; Yang, Jing; Liu, Jin; Liu, Chujie; Lin, Jung-Fu


    Determination of the full elastic constants (cij) of methane hydrates (MHs) at extreme pressure-temperature environments is essential to our understanding of the elastic, thermodynamic, and mechanical properties of methane in MH reservoirs on Earth and icy satellites in the solar system. Here, we have investigated the elastic properties of singe-crystal cubic MH-sI, hexagonal MH-II, and orthorhombic MH-III phases at high pressures in a diamond anvil cell. Brillouin light scattering measurements, together with complimentary equation of state (pressure-density) results from X-ray diffraction and methane site occupancies in MH from Raman spectroscopy, were used to derive elastic constants of MH-sI, MH-II, and MH-III phases at high pressures. Analysis of the elastic constants for MH-sI and MH-II showed intriguing similarities and differences between the phases' compressional wave velocity anisotropy and shear wave velocity anisotropy. Our results show that these high-pressure MH phases can exhibit distinct elastic, thermodynamic, and mechanical properties at relevant environments of their respective natural reservoirs. These results provide new insight into the determination of how much methane exists in MH reservoirs on Earth and on icy satellites elsewhere in the solar system and put constraints on the pressure and temperature conditions of their environment.

  13. Elasticity of methane hydrate phases at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Beam, Jennifer; Yang, Jing; Liu, Jin [Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Liu, Chujie [Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Lin, Jung-Fu, E-mail: [Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Center for High Pressure Science and Advanced Technology Research (HPSTAR), Shanghai 201203 (China)


    Determination of the full elastic constants (c{sub ij}) of methane hydrates (MHs) at extreme pressure-temperature environments is essential to our understanding of the elastic, thermodynamic, and mechanical properties of methane in MH reservoirs on Earth and icy satellites in the solar system. Here, we have investigated the elastic properties of singe-crystal cubic MH-sI, hexagonal MH-II, and orthorhombic MH-III phases at high pressures in a diamond anvil cell. Brillouin light scattering measurements, together with complimentary equation of state (pressure-density) results from X-ray diffraction and methane site occupancies in MH from Raman spectroscopy, were used to derive elastic constants of MH-sI, MH-II, and MH-III phases at high pressures. Analysis of the elastic constants for MH-sI and MH-II showed intriguing similarities and differences between the phases′ compressional wave velocity anisotropy and shear wave velocity anisotropy. Our results show that these high-pressure MH phases can exhibit distinct elastic, thermodynamic, and mechanical properties at relevant environments of their respective natural reservoirs. These results provide new insight into the determination of how much methane exists in MH reservoirs on Earth and on icy satellites elsewhere in the solar system and put constraints on the pressure and temperature conditions of their environment.

  14. Theoretical Predictions of Phase Transitions at Ultra-high Pressures (United States)

    Boates, Brian


    We present ab initio calculations of the high-pressure phase diagrams of important planetary materials such as CO2, MgSiO3, and MgO. For CO2, we predict a series of distinct liquid phases over a wide pressure (P) and temperature (T) range, including a first-order transition to a dense polymer liquid. We have computed finite-temperature free energies of liquid and solid CO2 phases to determine the melting curve beyond existing measurements and investigate possible phase separation transitions. The interaction of these phase boundaries with the mantle geotherm will also be discussed. Furthermore, we find evidence for a vast pressure-temperature regime where molten MgSiO3 decomposes into liquid SiO2 and solid MgO, with a volume change of approximately 1.2 percent. The demixing transition is driven by the crystallization of MgO ? the reaction only occurs below the high-pressure MgO melting curve. The predicted transition pressure at 10,000 K is in close proximity to an anomaly reported in recent laser-driven shock experiments of MgSiO3. We also present new results for the high-pressure melting curve of MgO and its B1-B2 solid phase transition, with a triple point near 364 GPa and 12,000 K.

  15. Chebyshev super spectral viscosity method for a fluidized bed model

    CERN Document Server

    Sarra, S A


    A Chebyshev super spectral viscosity method and operator splitting are used to solve a hyperbolic system of conservation laws with a source term modeling a fluidized bed. The fluidized bed displays a slugging behavior which corresponds to shocks in the solution. A modified Gegenbauer postprocessing procedure is used to obtain a solution which is free of oscillations caused by the Gibbs-Wilbraham phenomenon in the spectral viscosity solution. Conservation is maintained by working with unphysical negative particle concentrations.

  16. Planar near-nozzle velocity measurements during a single high-pressure fuel injection (United States)

    Schlüßler, Raimund; Gürtler, Johannes; Czarske, Jürgen; Fischer, Andreas


    In order to reduce the fuel consumption and exhaust emissions of modern Diesel engines, the high-pressure fuel injections have to be optimized. This requires continuous, time-resolved measurements of the fuel velocity distribution during multiple complete injection cycles, which can provide a deeper understanding of the injection process. However, fuel velocity measurements at high-pressure injection nozzles are a challenging task due to the high velocities of up to 300 m/s, the short injection durations in the range and the high fuel droplet density especially near the nozzle exit. In order to solve these challenges, a fast imaging Doppler global velocimeter with laser frequency modulation (2D-FM-DGV) incorporating a high-speed camera is presented. As a result, continuous planar velocity field measurements are performed with a measurement rate of 200 kHz in the near-nozzle region of a high-pressure Diesel injection. The injection system is operated under atmospheric surrounding conditions with injection pressures up to 1400 bar thereby reaching fuel velocities up to 380 m/s. The measurements over multiple entire injection cycles resolved the spatio-temporal fluctuations of the fuel velocity, which occur especially for low injection pressures. Furthermore, a sudden setback of the velocity at the beginning of the injection is identified for various injection pressures. In conclusion, the fast measurement system enables the investigation of the complete temporal behavior of single injection cycles or a series of it. Since this eliminates the necessity of phase-locked measurements, the proposed measurement approach provides new insights for the analysis of high-pressure injections regarding unsteady phenomena.

  17. Anomalous perovskite PbRuO3 stabilized under high pressure (United States)

    Cheng, J.-G.; Kweon, K. E.; Zhou, J.-S.; Alonso, J. A.; Kong, P.-P.; Liu, Y.; Jin, Changqing; Wu, Junjie; Lin, Jung-Fu; Larregola, S. A.; Yang, Wenge; Shen, Guoyin; MacDonald, A. H.; Manthiram, Arumugam; Hwang, G. S.; Goodenough, John B.


    Perovskite oxides ABO3 are important materials used as components in electronic devices. The highly compact crystal structure consists of a framework of corner-shared BO6 octahedra enclosing the A-site cations. Because of these structural features, forming a strong bond between A and B cations is highly unlikely and has not been reported in the literature. Here we report a pressure-induced first-order transition in PbRuO3 from a common orthorhombic phase (Pbnm) to an orthorhombic phase (Pbn21) at 32 GPa by using synchrotron X-ray diffraction. This transition has been further verified with resistivity measurements and Raman spectra under high pressure. In contrast to most well-studied perovskites under high pressure, the Pbn21 phase of PbRuO3 stabilized at high pressure is a polar perovskite. More interestingly, the Pbn21 phase has the most distorted octahedra and a shortest Pb—Ru bond length relative to the average Pb—Ru bond length that has ever been reported in a perovskite structure. We have also simulated the behavior of the PbRuO3 perovskite under high pressure by first principles calculations. The calculated critical pressure for the phase transition and evolution of lattice parameters under pressure match the experimental results quantitatively. Our calculations also reveal that the hybridization between a Ru:t2g orbital and an sp hybrid on Pb increases dramatically in the Pbnm phase under pressure. This pressure-induced change destabilizes the Pbnm phase to give a phase transition to the Pbn21 phase where electrons in the overlapping orbitals form bonding and antibonding states along the shortest Ru—Pb direction at P > Pc. PMID:24277807

  18. Shear viscosity of shocked metals at mega-bar pressures (United States)

    Liu, Fu-Sheng


    Viscosity of metals at high pressures and temperatures has been one of the most concerned problems in weapon physics and geophysics, e.g., the shear viscosity coefficients of substances in earth's mantle and earth's core at mega-bar pressures are needed for understanding the core mantle convection in deep earth. But the experimental data is very scarce because the conventional measurement methods can hardly be applied to such compression conditions [1]. In this talk, the principle of small-disturbance perturbation method [2] is re-investigated based on both the analytic solution and the numerical solution of the two-dimentional shock flow of sinusoidal distubance on front. In numerical solution, the real viscosity, which governs the flow behind the shock front and the perturbation damping feature, and the artificial viscosity, whick controls the numerical oscillation, separately treated. The relation between the viscosity of flow and the damping features of perturbation amplitude is quantitatively established for the loading situations of Sakharov's [3] and a flyer-impact situation with a finite disturbance. The later is the theoretical basis to develop a new experimental method, called the flyer-impact small-disturbance method [4]. In the flyer-impact small-disturbance method, the two-stage light-gas gun is used to launch a metal flyer. When the flyer directly impacts on the wedge-shaped sample with a sinusoidal surface, a two-dimensional shock flow of sinusoidal distubance on its front is generated. The amplitude of disturbance and its dependance with propagation distance is measured by use of an electric pin-array probe or a fibre-array probe. Correspondingly, the solution of the flow is given by numerically solving the hydrodynamic equations by the finite difference technique to find out the quantative correlations among the amplitude decay, the initial distribution of flow, the amplitude of initial disturbance, the shear viscosity of the flow, and the material

  19. Cryogenic Transport of High-Pressure-System Recharge Gas (United States)

    Ungar, Eugene K,; Ruemmele, Warren P.; Bohannon, Carl


    A method of relatively safe, compact, efficient recharging of a high-pressure room-temperature gas supply has been proposed. In this method, the gas would be liquefied at the source for transport as a cryogenic fluid at or slightly above atmospheric pressure. Upon reaching the destination, a simple heating/expansion process would be used to (1) convert the transported cryogenic fluid to the room-temperature, high-pressure gaseous form in which it is intended to be utilized and (2) transfer the resulting gas to the storage tank of the system to be recharged. In conventional practice for recharging high-pressure-gas systems, gases are transported at room temperature in high-pressure tanks. For recharging a given system to a specified pressure, a transport tank must contain the recharge gas at a much higher pressure. At the destination, the transport tank is connected to the system storage tank to be recharged, and the pressures in the transport tank and the system storage tank are allowed to equalize. One major disadvantage of the conventional approach is that the high transport pressure poses a hazard. Another disadvantage is the waste of a significant amount of recharge gas. Because the transport tank is disconnected from the system storage tank when it is at the specified system recharge pressure, the transport tank still contains a significant amount of recharge gas (typically on the order of half of the amount transported) that cannot be used. In the proposed method, the cryogenic fluid would be transported in a suitably thermally insulated tank that would be capable of withstanding the recharge pressure of the destination tank. The tank would be equipped with quick-disconnect fluid-transfer fittings and with a low-power electric heater (which would not be used during transport). In preparation for transport, a relief valve would be attached via one of the quick-disconnect fittings (see figure). During transport, the interior of the tank would be kept at a near

  20. Combined effects of high pressure homogenization treatment and citral on microbiological quality of apricot juice. (United States)

    Patrignani, Francesca; Tabanelli, Giulia; Siroli, Lorenzo; Gardini, Fausto; Lanciotti, Rosalba


    High pressure homogenization (HPH) technique is able to significantly reduce spoilage microbiota in fruit juice. On the other hand, aroma compounds and essential oils can have a key role in the microbial stability of these products. For this reason, the aim of this work was to evaluate the combined effects of an aroma compound (citral, used at a concentration of 50 mg/l) and HPH treatments (performed at 100 MPa for 1-8 successive passes) on the inactivation dynamics of Saccharomyces cerevisiae SPA strain inoculated in apricot juices at level of about 4.5 log CFU/ml. Moreover, growth of surviving yeast cells was measured during the storage of the treated juice at 10°C and pH, water activity, viscosity and volatile molecule profile of apricot juice were studied. Since citral had been diluted in ethanol before the addition to juice, also samples with only ethanol added at the same volume used to dissolve citral were considered. The results showed that yeast cell viability decreased with the increases of passes at 100 MPa and the relationship between yeast cell loads and number of passes at 100 MPa followed a linear trend. In addition, the effect of HPH treatment can be notably potentiated throughout the presence of citral and ethanol, increasing the time necessary to reach a spoilage threshold during storage. The volatile profiles of the juices added with citral showed a substitution by yeast metabolism of this aldehyde with molecule characterized by a lower antimicrobial activity such as alcohols. The HPH treatments had also a significant effect on pH and viscosity of apricot juices while did not affect a(w). Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Two-phase convection in Ganymede's high-pressure ice layer - Implications for its geological evolution (United States)

    Kalousová, Klára; Sotin, Christophe; Choblet, Gaël; Tobie, Gabriel; Grasset, Olivier


    Ganymede, the largest moon in the solar system, has a fully differentiated interior with a layer of high-pressure (HP) ice between its deep ocean and silicate mantle. In this paper, we study the dynamics of this layer using a numerical model of two-phase ice-water mixture in two-dimensional Cartesian geometry. While focusing on the generation of water at the silicate/HP ice interface and its upward migration towards the ocean, we investigate the effect of bottom heat flux, the layer thickness, and the HP ice viscosity and permeability. Our results suggest that melt can be generated at the silicate/HP ice interface for small layer thickness ( ≲ 200 km) and high values of heat flux ( ≳ 20 mW m-2) and viscosity ( ≳ 1015 Pa s). Once generated, the water is transported through the layer by the upwelling plumes. Depending on the vigor of convection, it stays liquid or it may freeze before melting again as the plume reaches the temperate (partially molten) layer at the boundary with the ocean. The thickness of this layer as well as the amount of melt that is extracted from it is controlled by the permeability of the HP ice. This process constitutes a means of transporting volatiles and salts that might have dissolved into the melt present at the silicate/HP ice interface. As the moon cools down, the HP ice layer becomes less permeable because the heat flux from the silicates decreases and the HP ice layer thickens.

  2. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela


    The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

  3. Influence of CO{sup 2} on PVT properties of an oil crude at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nilo Ricardo; Bonet, Euclides Jose [Centro de Estudos de Petroleo (CEPETRO/UNICAMP), SP (Brazil); Elias Junior, Antonio; Trevisan, Osvair Vidal [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo


    The current oil frontier in Brazil is in Santos and Campos Basins, where huge oil accumulations were identified recently. Well tests have shown high values of pressure and concentration of carbon dioxide in these reservoirs. The characterization of the fluids existing in the pores of the reservoir rocks is a task for the exploitation of the hydrocarbons. The objective of this work is to present the experimental set up that was assembled to perform PVT analysis for oils at high pressure, moderate temperature and high CO{sub 2} content, oils analogous to that found in the new Brazilian pre-salt discoveries. Samples of dead oil and synthetic gas were received at the laboratory, where the recombination was carried out to obtain live oil, with twelve mole percent CO{sub 2}. The fluids were maintained inside special cylinders, with a floating piston, separating two compartments, one with the test fluid and the other with hydraulic fluid. Pressure was provided by a positive displacement pump connected to the bottles. The experiments achieved pressures up to 70 MPa at constant temperature, conditions expected for the reservoir. Starting at the high pressure, the fluid volume was increased by withdrawing the hydraulic fluid from the cylinder. Pressure and volume were recorded to determine the bubble point and compressibility of the system. The pressure drop continued until the mixture was in the two phase region, finishing the constant composition expansion process. After that, the sample was re-pressurized and the PVT bottle was agitated to reach the thermodynamic equilibrium, when the live oil was at single phase again. An aliquot of this mixture was transferred, keeping their pressure and temperature conditions, to a high pressure viscometer and to a densimeter. Another portion of live oil was flashed to a test tube and to a gasometer, to render the gas oil ratio. Afterwards, successive additions of carbon dioxide increased its concentration in live oil to 15, 20 and 35

  4. Probing of Fast Chemical Dynamics at High Pressures and Temperatures using Pulsed Laser Techniques (United States)


    The Journal of Chemical Physics , (08 2011): 1. doi: 10.1063/1.3626860 13.00 23.00 20.00 18.00 17.00 16.00 15.00 24.00 38.00 08/30/2011 08/30/2011...diagram, The Journal of Chemical Physics , (05 2011): 1. doi: 10.1063/1.3574009 Andrew Kung, Alexander F. Goncharov, Chang sheng Zha, Peter Eng...Wendy L. Mao. Compressional, temporal, and compositional behavior of H2-O2 compound formed by high pressure x-ray irradiation, The

  5. Viscosity Measurement for Tellurium Melt (United States)

    Lin, Bochuan; Li, Chao; Ban, Heng; Scripa, Rosalia N.; Su, Ching-Hua; Lehoczky, Sandor L.


    The viscosity of high temperature Te melt was measured using a new technique in which a rotating magnetic field was applied to the melt sealed in a suspended ampoule, and the torque exerted by rotating melt flow on the ampoule wall was measured. Governing equations for the coupled melt flow and ampoule torsional oscillation were solved, and the viscosity was extracted from the experimental data by numerical fitting. The computational result showed good agreement with experimental data. The melt velocity transient initiated by the rotating magnetic field reached a stable condition quickly, allowing the viscosity and electrical conductivity of the melt to be determined in a short period.

  6. Magnetic properties of Mn{sub 1.9}Cu{sub 0.1}Sb under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yoshihiro; Hiroi, Masahiko; Mitsui, Yoshifuru; Koyama, Keiichi, E-mail: [Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Matsubayashi, Kazuyuki; Uwatoko, Yoshiya [Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581 (Japan)


    Magnetization measurements were carried out for polycrystalline Mn{sub 1.9}Cu{sub 0.1}Sb in magnetic fields up to 5 T in the 10-300 K temperature range under high pressures up to 1 GPa in order to investigate the magnetic properties and the thermal transformation arrest (TTA) phenomenon under high pressures. The spin-reorientation temperature increased from 202 K for 0.1 MPa to 244 K for 1 GPa, whereas the transition temperature from the ferrimagnetic (FRI) to antiferromagnetic (AFM) state did not drastically change at ∼116 K. The magnetic relaxation behavior from the FRI to AFM state was observed in 10 < T ≤ 70 K, which was analyzed using the Kohlrausch-Williams-Watts model. Obtained results indicated that the TTA phenomenon of Mn{sub 1.9}Cu{sub 0.1}Sb was suppressed by the application of high pressures.

  7. High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence. (United States)

    Najiba, Shah; Chen, Jiuhua


    One of the major obstacles to the use of hydrogen as an energy carrier is the lack of proper hydrogen storage material. Lithium amidoborane has attracted significant attention as hydrogen storage material. It releases ∼10.9 wt% hydrogen, which is beyond the Department of Energy target, at remarkably low temperature (∼90 °C) without borazine emission. It is essential to study the bonding behavior of this potential material to improve its dehydrogenation behavior further and also to make rehydrogenation possible. We have studied the high-pressure behavior of lithium amidoborane in a diamond anvil cell using in situ Raman spectroscopy. We have discovered that there is no dihydrogen bonding in this material, as the N-H stretching modes do not show redshift with pressure. The absence of the dihydrogen bonding in this material is an interesting phenomenon, as the dihydrogen bonding is the dominant bonding feature in its parent compound ammonia borane. This observation may provide guidance to the improvement of the hydrogen storage properties of this potential material and to design new material for hydrogen storage application. Also two phase transitions were found at high pressure at 3.9 and 12.7 GPa, which are characterized by sequential changes of Raman modes.

  8. An in situ tribometer for measuring friction and wear of polymers in a high pressure hydrogen environment (United States)

    Duranty, Edward R.; Roosendaal, Timothy J.; Pitman, Stan G.; Tucker, Joseph C.; Owsley, Stanley L.; Suter, Jonathan D.; Alvine, Kyle J.


    High pressure hydrogen effects on the friction and wear of polymers are of importance to myriad applications. Of special concern are those used in the infrastructure for hydrogen vehicle refueling stations, including compressor sliding seals, valves, and actuators. While much is known about potentially damaging embrittlement effects of hydrogen on metals, relatively little is known about the effects of high pressure hydrogen on polymers. However, based on the limited results that are published in the literature, polymers also apparently exhibit compatibility issues with hydrogen. An additional study is needed to elucidate these effects to avoid incompatibilities either through design or material selection. As part of this effort, we present here in situ high pressure hydrogen studies of the friction and wear on example polymers. To this end, we have built and demonstrated a custom-built pin-on-flat linear reciprocating tribometer and demonstrated its use with in situ studies of friction and wear behavior of nitrile butadiene rubber polymer samples in 28 MPa hydrogen. Tribology results indicate that friction and wear is increased in high pressure hydrogen as compared both with values measured in high pressure argon and ambient air conditions.

  9. The effect of the volume fraction and viscosity on the compression and tension behavior of the cobalt-ferrite magneto-rheological fluids

    Directory of Open Access Journals (Sweden)

    H. Shokrollahi


    Full Text Available The purpose of this work is to investigate the effects of the volume fraction and bimodal distribution of solid particles on the compression and tension behavior of the Co-ferrite-based magneto-rheological fluids (MRFs containing silicon oil as a carrier. Hence, Co-ferrite particles (CoFe2O4 with two various sizes were synthesized by the chemical co-precipitation method and mixed so as to prepare the bimodal MRF. The X-Ray Diffraction (XRD analysis, Fourier Transform Infrared Spectroscopy (FTIR, Laser Particle Size Analysis (LPSA and Vibrating Sample Magnetometer (VSM were conducted to examine the structural and magnetic properties, respectively. The results indicated that the increase of the volume fraction has a direct increasing influence on the values of the compression and tension strengths of fluids. In addition, the compression and tension strengths of the mixed MRF sample (1.274 and 0.647 MPa containing 60 and 550 nm samples were higher than those of the MRF sample with the same volume fraction and uniform particle size of 550 nm.

  10. Analysis, design and testing of high pressure waterjet nozzles (United States)

    Mazzoleni, Andre P.


    The Hydroblast Research Cell at MSFC is both a research and a processing facility. The cell is used to investigate fundamental phenomena associated with waterjets as well as to clean hardware for various NASA and contractor projects. In the area of research, investigations are made regarding the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current industrial methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents, and high pressure waterjet cleaning has proven to be a viable alternative. Standard methods of waterjet cleaning use hand held or robotically controlled nozzles. The nozzles used can be single-stream or multijet nozzles, and the multijet nozzles may be mounted in a rotating head or arranged in a fan-type shape. We consider in this paper the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage (e.g. the formation of 'islands' of material not cleaned) and damage to the substrate from the waterjet have been observed. In addition, current stripping operations require the nozzle to be placed at a standoff distance of approximately 2 inches in order to achieve adequate performance. This close proximity of the nozzle to the target to be cleaned poses risks to the nozzle and the target in the event of robot error or the striking of unanticipated extrusions on the target surface as the nozzle sweeps past. Two key motivations of this research are to eliminate the formation of 'coating islands' and to increase the allowable standoff distance of the nozzle.

  11. Equilibria of oligomeric proteins under high pressure - A theoretical description. (United States)

    Ingr, Marek; Kutálková, Eva; Hrnčiřík, Josef; Lange, Reinhard


    High pressure methods have become a useful tool for studying protein structure and stability. Using them, various physico-chemical processes including protein unfolding, aggregation, oligomer dissociation or enzyme-activity decrease were studied on many different proteins. Oligomeric protein dissociation is a process that can perfectly utilize the potential of high-pressure techniques, as the high pressure shifts the equilibria to higher concentrations making them better observable by spectroscopic methods. This can be especially useful when the oligomeric form is highly stable at atmospheric pressure. These applications may be, however, hindered by less intensive experimental response as well as interference of the oligomerization equilibria with unfolding or aggregation of the subunits, but also by more complex theoretical description. In this study we develop mathematical models describing different kinds of oligomerization equilibria, both closed (equilibrium of monomer and the highest possible oligomer without any intermediates) and consecutive. Closed homooligomer equilibria are discussed for any oligomerization degree, while the more complex heterooligomer equilibria and the consecutive equilibria in both homo- and heterooligomers are taken into account only for dimers and trimers. In all the cases, fractions of all the relevant forms are evaluated as functions of pressure and concentration. Significant points (inflection points and extremes) of the resulting transition curves, that can be determined experimentally, are evaluated as functions of pressure and/or concentration. These functions can be further used in order to evaluate the thermodynamic parameters of the system, i.e. atmospheric-pressure equilibrium constants and volume changes of the individual steps of the oligomer-dissociation processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. LOX vaporization in high-pressure, hydrogen-rich gas (United States)

    Litchford, Ron J.; Jeng, San-Mou


    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  13. High Pressure Serpentinization Catalysed by Awaruite in Planetary Bodies (United States)

    Neto-Lima, J.; Fernández-Sampedro, M.; Prieto-Ballesteros, O.


    Recent discoveries from planetary missions show that serpentinization process may act significantly on the geological evolution and potential habitability of the icy bodies of the Solar System, like Enceladus or Europa. Here we review the available experimental data so far about methane formation occurring during serpentinization, which is potentially relevant to icy moons, and present our results using awaruite as a catalyst of this process. The efficiency of awaruite and high pressure in the Fischer-Tropsch and Sabatier Type reactions are evaluated here when olivine is incubated.

  14. Piston cylinder cell for high pressure ultrasonic pulse echo measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kepa, M. W., E-mail:; Huxley, A. D. [SUPA, Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Ridley, C. J.; Kamenev, K. V. [Centre for Science at Extreme Conditions and School of Engineering, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)


    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe{sub 2}.

  15. System Study: High-Pressure Safety Injection 1998-2014

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.


    This report presents an unreliability evaluation of the high-pressure safety injection system (HPSI) at 69 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2014 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10 year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPSI results.

  16. System Study: High-Pressure Coolant Injection 1998-2014

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.


    This report presents an unreliability evaluation of the high-pressure coolant injection system (HPCI) at 25 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2014 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10 year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPCI results.

  17. High pressure and high temperature behaviour of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Thakar, Nilesh A. [K. K. Shah Jarodwala Maninagar Science College, Rambaug, Maninagar, Ahmedabad-380008 (India); Bhatt, Apoorva D. [Department of Physics, Gujarat University, Ahmedabad-380009 (India); Pandya, Tushar C., E-mail: [St. Xavier' s College, Navrangpura, Ahmedabad-380009 (India)


    The thermodynamic properties with the wurtzite (B4) and rocksalt (B1) phases of ZnO under high pressures and high temperatures have been investigated using Tait's Equation of state (EOS). The effects of pressures and temperatures on thermodynamic properties such as bulk modulus, thermal expansivity and thermal pressure are explored for both two structures. It is found that ZnO material gradually softens with increase of temperature while it hardens with the increment of the pressure. Our predicted results of thermodynamics properties for both the phases of ZnO are in overall agreement with the available data in the literature.

  18. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.


    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low...... pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern...

  19. System Study: High-Pressure Safety Injection 1998–2013

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.


    This report presents an unreliability evaluation of the high-pressure safety injection system (HPSI) at 69 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2013 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10-year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPSI results.

  20. High pressure melting curves of silver, gold and copper

    Directory of Open Access Journals (Sweden)

    Ho Khac Hieu


    Full Text Available In this work, based on the Lindemann's formula of melting and the pressure-dependent Grüneisen parameter, we have investigated the pressure effect on melting temperature of silver, gold and copper metals. The analytical expression of melting temperature as a function of volume compression has been derived. Our results are compared with available experimental data as well as with previous theoretical studies and the good and reasonable agreements are found. We also proposed the potential of this approach on predicting melting of copper at very high pressure.

  1. High pressure melting curves of silver, gold and copper

    Energy Technology Data Exchange (ETDEWEB)

    Hieu, Ho Khac, E-mail: [Research and Development Center for Science and Technology, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Ha, Nguyen Ngoc [VNU-Hanoi University of Science, 334 Nguyen Trai, Hanoi (Viet Nam)


    In this work, based on the Lindemann's formula of melting and the pressure-dependent Grüneisen parameter, we have investigated the pressure effect on melting temperature of silver, gold and copper metals. The analytical expression of melting temperature as a function of volume compression has been derived. Our results are compared with available experimental data as well as with previous theoretical studies and the good and reasonable agreements are found. We also proposed the potential of this approach on predicting melting of copper at very high pressure.

  2. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V


    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  3. Finite volume analysis and optimisation of a high pressure homogeniser


    Clarke, Andrew P.


    The homogeniser is a machine that is mostly used to change the appearance and rheological properties of a fluid by means of a high pressure radial gap. It can be implemented to kill off harmful bacteria and organisms as well as reduce the size of individual components or particles to increase the shelf live of many products. The homogeniser can be used to release useful organic materials from within cells or microbes. The homogeniser can be found in small scale production and large scale prod...

  4. System Study: High-Pressure Safety Injection 1998–2012

    Energy Technology Data Exchange (ETDEWEB)

    T. E. Wierman


    This report presents an unreliability evaluation of the high-pressure safety injection system (HPSI) at 69 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPSI results.

  5. System Study: High-Pressure Core Spray 1998–2013

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.


    This report presents an unreliability evaluation of the high-pressure core spray (HPCS) at eight U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2013 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10-year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPCS results.

  6. System Study: High-Pressure Coolant Injection 1998–2013

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States). Risk Assessment and Management Services Dept.


    This report presents an unreliability evaluation of the high-pressure coolant injection system (HPCI) at 25 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2013 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10-year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPCI results.

  7. Investigation of Acrylic Acid at High Pressure using Neutron Diffraction

    DEFF Research Database (Denmark)

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon


    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalised using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new...... phase at ~0.8 GPa and remains molecular to 7.2 GPa before polymerising on decompression to ambient pressure. The resulting product is analysed via Raman, FT-IR spectroscopy and Differential Scanning Calorimetry and found to possess a different molecular structure compared with polymers produced via...

  8. Primary obstructive megaureter: the role of high pressure balloon dilation. (United States)

    Romero, Rosa M; Angulo, Jose Maria; Parente, Alberto; Rivas, Susana; Tardáguila, Ana Rosa


    There is a growing interest in minimally invasive treatment of primary obstructive megaureter (POM) in children. The absence of long-term follow-up data, however, makes it difficult to establish the indication for an endoscopic approach. The aim of our study is to determine the long-term efficacy of endourologic high-pressure balloon dilation of the vesicoureteral junction (VUJ) in children with POM that necessitates surgical treatment. We retrospectively reviewed the clinical records from children with POM who were treated with endourologic high-pressure balloon dilation of the VUJ from March 2003 to April 2010. To determine the long-term, a cohort study was conducted in November 2011. Endourologic dilation of the VUJ was performed with a semicompliant high-pressure balloon (2.7 FG) with a minimum balloon size of 3 mm, followed by placement of a Double-J stent. We have treated 29 (32 renal units, left [n=16], right [n=10] and bilateral [n=3]) children with a diagnosis of POM within this period. The median age at the time of the endourologic treatment was 4.04 months (range 1.6-39 months). In three cases, an open ureteral reimplantation was needed, in two cases because of intraoperative technical failure and postoperative Double-J stent migration in one patient. The 26 children (29 renal units) who had a successful endourologic dilation of the VUJ were followed with ultrasonography and MAG-3-Lasix (furosemide) studies that showed a progressive improvement of both the ureterohydronephrosis and drainage in the first 18 months in 20 patients (23 renal units) (69%). In two patients who were treated with a 3 mm balloon, a further dilation was needed, with an excellent outcome. The cohort study (at a median follow-up of 47 months) showed that in all patients who had a good outcome at the 18-month follow-up after endourologic balloon dilation remained asymptomatic with resolution of ureterohydronephrosis on the US and good drainage on the renogram, in the children

  9. The phase stability of terephthalic acid under high pressure (United States)

    Sun, Lin; Zhao, Yue; Shang, Yujie; Sun, Chenglin; Zhou, Mi


    Terephthalic acid has been investigated by Raman spectroscopy up to 15 GPa. According to ab initio calculations, it can be speculated that both of π-π stacking interactions between molecules and the symmetry of hydrogen bonds are enhanced with gradually increasing pressure. Furthermore, we use the Hirshfeld surface to map the π-π stacking interaction in the TPA molecule at high pressure. The Raman spectra and ab initio calculation results indicate that the phase stability of TPA is related to the one-dimensional hydrogen bond network and inter-chain aromatic π-π stacking interaction.

  10. High-pressure effects on intramolecular electron transfer compounds

    CERN Document Server

    He Li Ming; Li Hong; Zhang Bao Wen; Li Yi; Yang Guo Qiang


    We explore the effect of pressure on the fluorescence spectra of the intramolecular electron transfer compound N-(1-pyrenylmethyl), N-methyl-4-methoxyaniline (Py-Am) and its model version, with poly(methyl methacrylate) blended in, at high pressure up to 7 GPa. The emission properties of Py-Am and pyrene show distinct difference with the increase of pressure. This difference indicates the strength of the charge transfer interaction resulting from the adjusting of the conformation of Py-Am with increase of pressure. The relationship between the electronic state of the molecule and pressure is discussed.

  11. A hemispherical high-pressure xenon gamma radiation spectrometer

    CERN Document Server

    Kessick, R


    A prototype hemispherical high-pressure xenon gamma radiation spectrometer was designed, constructed and tested. The detector consists of a pair of concentric hemispherical electrodes contained inside a thin-walled stainless steel pressure dome. Detector performance parameters such as energy resolution, linearity and vibration sensitivity were determined and compared to previous cylindrical and planar designs. Without a Frisch grid, the hemispherical detector provides a total room temperature energy resolution of 6% at 662 keV and is relatively insensitive to acoustic interference.

  12. High pressure water electrolysis for space station EMU recharge (United States)

    Lance, Nick; Puskar, Michael; Moulthrop, Lawrence; Zagaja, John


    A high pressure oxygen recharge system (HPORS), is being developed for application on board the Space Station. This electrolytic system can provide oxygen at up to 6000 psia without a mechanical compressor. The Hamilton standard HPORS based on a solid polymer electrolyte system is an extension of the much larger and succesful 3000 psia system of the U.S. Navy. Cell modules have been successfully tested under conditions beyond which spacecraft may encounter during launch. The control system with double redundancy and mechanical backups for all electronically controlled components is designed to ensure a safe shutdown.

  13. Viscosity of particle laden films (United States)

    Timounay, Yousra; Rouyer, Florence


    We perform retraction experiments on soap films where large particles bridge the two interfaces. Local velocities are measured by PIV during the unstationnary regime. The velocity variation in time and space can be described by a continuous fluid model from which effective viscosity (shear and dilatational) of particulate films is measured. The 2D effective viscosity of particulate films η2D increases with particle surface fraction ϕ: at low ϕ, it tends to the interfacial dilatational viscosity of the liquid/air interfaces and it diverges at the critical particle surface fraction ϕc ≃ 0.84. Experimental data agree with classical viscosity laws of hard spheres suspensions adapted to the 2D geometry, assuming viscous dissipation resulting from the squeeze of the liquid/air interfaces between the particles. Finally, we show that the observed viscous dissipation in particulate films has to be considered to describe the edge velocity during a retraction experiment at large particle coverage.

  14. Structural and physicochemical properties of lotus seed starch treated with ultra-high pressure. (United States)

    Guo, Zebin; Zeng, Shaoxiao; Lu, Xu; Zhou, Meiling; Zheng, Mingjing; Zheng, Baodong


    Aqueous lotus seed starch suspensions (15%, w/w) were subjected to ultra-high pressure treatment (UHP, 100-600 MPa) for 30 min. The effects of UHP treatment on the structural and physicochemical properties of starch were investigated. The SEM and laser diffraction particle size analysis revealed that UHP treatment affected the shape and size distribution of starch granules. The morphological structure of starch was completely destroyed at 600 MPa, indicating complete gelatinization. Analysis of HPSEC-MALLS-RI suggested that the dispersity index of UHP-treated starch were decreased from 1.28 to 1.11. According to XRD analyses, UHP treatment converted native starch (C-type) into a B-type pattern. The swelling power and solubility presented a significant decrease at 85 and 95 °C, but opposite trends were found at 55-75 °C. The DSC results indicated a reduction in gelatinization temperatures and enthalpy with increasing pressure treatment. The RVA viscograms revealed that UHP-treated starch showed a decreased breakdown and setback viscosity, reflecting lower retrogradation tendency compared to native starch. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Measurements of mixtures with carbon dioxide under supercritical conditions using commercial high pressure equipment

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luciana L.P.R. de; Rutledge, Luis Augusto Medeiros; Moreno, Eesteban L.; Hovell, Ian; Rajagopal, Krishnaswamy [Universidade Federal do Rio de Janeiro (LATCA-EQ-UFRJ), RJ (Brazil). Escola de Quimica. Lab. de Termodinamica e Cinetica Aplicada


    There is a growing interest in studying physical properties of binary and multicomponent fluid mixtures with supercritical carbon dioxide (CO{sub 2}) over an extended range of temperature and pressure. The estimation of properties such as density, viscosity, saturation pressure, compressibility, solubility and surface tension of mixtures is important in design, operation and control as well as optimization of chemical processes especially in extractions, separations, catalytic and enzymatic reactions. The phase behaviour of binary and multicomponent mixtures with supercritical CO{sub 2} is also important in the production and refining of petroleum where mixtures of paraffin, naphthene and aromatics with supercritical fluids are often encountered. Petroleum fluids can present a complex phase behaviour in the presence of CO{sub 2}, where two-phase (VLE and LLE) and three phase regions (VLLE) might occur within ranges of supercritical conditions of temperature and pressure. The objective of this study is to develop an experimental methodology for measuring the phase behaviour of mixtures containing CO{sub 2} in supercritical regions, using commercial high-pressure equipment. (author)

  16. Properties of lotus seed starch-glycerin monostearin complexes formed by high pressure homogenization. (United States)

    Chen, Bingyan; Zeng, Shaoxiao; Zeng, Hongliang; Guo, Zebin; Zhang, Yi; Zheng, Baodong


    Starch-lipid complexes were prepared using lotus seed starch (LS) and glycerin monostearate (GMS) via a high pressure homogenization (HPH) process, and the effect of HPH on the physicochemical properties of LS-GMS complexes was investigated. The results of Fourier transform infrared spectroscopy and complex index analysis showed that LS-GMS complexes were formed at 40MPa by HPH and the complex index increased with the increase of homogenization pressure. Scanning electron microscopy displayed LS-GMS complexes present more nest-shape structure with increasing homogenization pressure. X-ray diffraction and differential scanning calorimetry results revealed that V-type crystalline polymorph was formed between LS and GMS, with higher homogenization pressure producing an increasingly stable complex. LS-GMS complex inhibited starch granules swelling, solubility and pasting development, which further reduced peak and breakdown viscosity. During storage, LS-GMS complexes prepared by 70-100MPa had higher Avrami exponent values and lower recrystallization rates compared with native starch, which suggested a lower retrogradation trendency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Quality comparison of elephant apple juices after high-pressure processing and thermal treatment. (United States)

    Nayak, Prakash Kumar; Rayaguru, Kalpana; Radha Krishnan, Kesavan


    In the present work, the effect of high pressure processing (HPP) on the quality parameters (pH, °Brix, total acidity, viscosity, colour, antioxidant activity, total phenols, total flavonoids, microbial flora, and sensory analysis) of elephant apple (Dillenia indica) juice was investigated. The juice samples were analysed periodically (0, 1, 2, 5, 10, 20, 30, 40, 50 and 60 days) during 60 days of storage period and results were compared with thermally processed as well as with untreated (fresh juice) samples. Slight variations had been observed in the quality parameters like pH, °Brix and total acidity. Other parameters like colour values, antioxidant activity, total phenols and total flavonoids were varied significantly (P < 0.05) in between the treated (HPP and thermal) and untreated juice samples. The microbial counts of the HPP treated samples were lower than the other samples. Sensory results also showed similar results to those of the other analyses that the treated samples were better for consumption rather than the untreated samples. The shelf-life of the HPP processed elephant apple juice was established as 60 days at 4 °C. This study showed that application of HPP effectively maintained quality attributes and extended shelf life of the elephant apple juice. It may be suggested that application of HPP could be considered for commercial application during storage and marketing. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Visualization of the drop deformation and break-up process in a high pressure homogenizer

    Energy Technology Data Exchange (ETDEWEB)

    Innings, F. [Tetra Pak Processing Systems, Ruben Rausings gata, SE-221 86 Lund (Sweden); Traegaardh, C. [Lund University, Box 124, SE-221 00 Lund (Sweden)


    For the creation of sub-micron emulsions in fluids of low viscosity the high pressure homogenizer (HPH) is usually chosen. One way of obtaining deeper knowledge of exactly what happens in the active region is to visualize it. In this work, a drop deformation and break-up visualization system based on a modified Particle Image Velocimetry (PIV) system is described. The system reproduces the gap in a HPH and has been used with pressures up to 18 MPa and drops as small as 5 {mu}m. The optics of the system are analyzed taking into account limiting factors such as the lens resolving power, the focal depth, and the duration of the laser pulses. It is shown that it is possible to resolve drops down to a few {mu}m moving in excess of 100 m/s, and that the main limitations are the resolving power and in the focal depth of the objectives. Examples are shown from capillary drop creation and from the deformation and break-up of drops in a HPH. It can be concluded that in a HPH, the drops are only deformed to a limited extent in the inlet of the gap, and that all drop break-up occurs far downstream of the gap. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  19. Molecular clutch drives cell response to surface viscosity. (United States)

    Bennett, Mark; Cantini, Marco; Reboud, Julien; Cooper, Jonathan M; Roca-Cusachs, Pere; Salmeron-Sanchez, Manuel


    Cell response to matrix rigidity has been explained by the mechanical properties of the actin-talin-integrin-fibronectin clutch. Here the molecular clutch model is extended to account for cell interactions with purely viscous surfaces (i.e., without an elastic component). Supported lipid bilayers present an idealized and controllable system through which to study this concept. Using lipids of different diffusion coefficients, the mobility (i.e., surface viscosity) of the presented ligands (in this case RGD) was altered by an order of magnitude. Cell size and cytoskeletal organization were proportional to viscosity. Furthermore, there was a higher number of focal adhesions and a higher phosphorylation of FAK on less-mobile (more-viscous) surfaces. Actin retrograde flow, an indicator of the force exerted on surfaces, was also seen to be faster on more mobile surfaces. This has consequential effects on downstream molecules; the mechanosensitive YAP protein localized to the nucleus more on less-mobile (more-viscous) surfaces and differentiation of myoblast cells was enhanced on higher viscosity. This behavior was explained within the framework of the molecular clutch model, with lower viscosity leading to a low force loading rate, preventing the exposure of mechanosensitive proteins, and with a higher viscosity causing a higher force loading rate exposing these sites, activating downstream pathways. Consequently, the understanding of how viscosity (regardless of matrix stiffness) influences cell response adds a further tool to engineer materials that control cell behavior. Copyright © 2018 the Author(s). Published by PNAS.

  20. Thermodynamic properties of liquid sodium under high pressure (United States)

    Li, Huaming; Zhang, Xiaoxiao; Sun, Yongli; Li, Mo


    Acquiring reliable thermodynamic properties in liquid metals at high pressure and temperature is still a challenge in both experiment and theory. Equation of state (EoS) offers an alternative approach free of many of the difficulties. Here using the EoS of a power law form we obtained the thermodynamic properties of liquid sodium under pressure along the isothermal lines, including isothermal buck modulus, thermal expansion coefficient, Grüneisen parameter, and Anderson-Grüneisen parameter. The results are in excellent agreement with available experimental data measured by a piezometer at high temperature and high pressure and sound velocity measurement with pulse-echo technique. We found that the pressure derivative of the isothermal bulk modulus at zero pressure is a monotonic function of temperature and has a value around 4. In addition, unexpected crossing points were found in the isobaric thermal expansion coefficient and Grüneisen parameter; and a minimum in the isobaric heat under isothermal compression was also observed. While some of these detailed predictions are yet to be confirmed by further experiment, our results suggest that the power law form may be a more suitable choice for the EoS of liquids metals.

  1. High Pressure Angle Gears: Comparison to Typical Gear Designs (United States)

    Handschuh, Robert F.; Zabrajsek, Andrew J.


    A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

  2. Iron Catalyst Chemistry in High Pressure Carbon Monoxide Nanotube Reactor (United States)

    Scott, Carl D.; Povitsky, Alexander; Dateo, Christopher; Gokcen, Tahir; Smalley, Richard E.


    The high-pressure carbon monoxide (HiPco) technique for producing single wall carbon nanotubes (SWNT) is analyzed using a chemical reaction model coupled with properties calculated along streamlines. Streamline properties for mixing jets are calculated by the FLUENT code using the k-e turbulent model for pure carbon monixide. The HiPco process introduces cold iron pentacarbonyl diluted in CO, or alternatively nitrogen, at high pressure, ca. 30 atmospheres into a conical mixing zone. Hot CO is also introduced via three jets at angles with respect to the axis of the reactor. Hot CO decomposes the Fe(CO)5 to release atomic Fe. Cluster reaction rates are from Krestinin, et aI., based on shock tube measurements. Another model is from classical cluster theory given by Girshick's team. The calculations are performed on streamlines that assume that a cold mixture of Fe(CO)5 in CO is introduced along the reactor axis. Then iron forms clusters that catalyze the formation of SWNTs from the Boudouard reaction on Fe-containing clusters by reaction with CO. To simulate the chemical process along streamlines that were calculated by the fluid dynamics code FLUENT, a time history of temperature and dilution are determined along streamlines. Alternative catalyst injection schemes are also evaluated.

  3. Inactivation of a Norovirus by High-Pressure Processing▿ (United States)

    Kingsley, David H.; Holliman, Daniel R.; Calci, Kevin R.; Chen, Haiqiang; Flick, George J.


    Murine norovirus (strain MNV-1), a propagable norovirus, was evaluated for susceptibility to high-pressure processing. Experiments with virus stocks in Dulbecco's modified Eagle medium demonstrated that at room temperature (20°C) the virus was inactivated over a pressure range of 350 to 450 MPa, with a 5-min, 450-MPa treatment being sufficient to inactivate 6.85 log10 PFU of MNV-1. The inactivation of MNV-1 was enhanced when pressure was applied at an initial temperature of 5°C; a 5-min pressure treatment of 350 MPa at 30°C inactivated 1.15 log10 PFU of virus, while the same treatment at 5°C resulted in a reduction of 5.56 log10 PFU. Evaluation of virus inactivation as a function of treatment times ranging from 0 to 150 s and 0 to 900 s at 5°C and 20°C, respectively, indicated that a decreasing rate of inactivation with time was consistent with Weibull or log-logistic inactivation kinetics. The inactivation of MNV-1 directly within oyster tissues was demonstrated; a 5-min, 400-MPa treatment at 5°C was sufficient to inactivate 4.05 log10 PFU. This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods. PMID:17142353

  4. Photoconductivity studies of the ferrocyanide ion under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Finston, M. I.


    The photoaquation of the ferrocyanide ion was studied using a high-pressure photoconductivity apparatus and a steady-state high-pressure mercury lamp. The first-order photocurrent rise-time could be related to the relative quantum efficiency of the photoaquation process, while the dark decay of the photocurrent yielded a relative value of the bimolecular rate-constant for the reverse reaction. Kinetic measurements were carried out on dilute solutions of potassium ferrocyanide in pure water, and in 20% ethanol. The photocurrent yield in aqueous solution was dependent upon secondary chemical equilibria which were sensitive to pressure in a predictable way. In ethanolic solution, the dependence of photocurrent yield on pressure followed the variation of the reciprocal solvent vicosity. In both aqueous and alcoholic solution, the photoaquation quantum efficiency decreased exponentially with pressure, as did the biomolecular rate-constant for the dark reaction in aqueous solution. The pressure dependence of the bimolecular rate-constant in the alcoholic solution indicated a diffusion-limited process. The pressure dependence of the photoaquation quantum yield, and of the bimolecular rate-constant in aqueous solution, was interpreted in terms of an activation volume model. The photoaquation data for both the aqueous and the alcoholic solutions agreed with a hypothetical mechanism whereby ligand-to-metal bond-breaking, and solvent-to-metal bond-formation, are effectively simultaneous. The results for the aqueous dark reaction strongly indicated breaking of the solvent-to-metal bond as the rate-limiting step.

  5. Ultrasonic level sensors for liquids under high pressure (United States)

    Zuckerwar, A. J.; Mazel, D. S.; Hodges, D. Y.


    An ultrasonic level sensor of novel design continuously measures the level of a liquid subjected to a high pressure (up to about 40 MPa), as is sometimes required for the effective transfer of the liquid. The sensor operates as a composite resonator fabricated from a standard high-pressure plug. A flat-bottom hole is machined into the plug along its center line. An ultrasonic transducer is bonded rigidly to the interior surface of the bottom wall, while the exterior surface is in contact with the liquid. Although the bottom wall is designed to satisfy the pressure code, it is still sufficiently thin to permit ready excitation of the axisymmetric plate modes of vibration. The liquid level is measured by a conventional pulse-echo technique. A prototype sensor was tested successfully in a 2300-l water vessel at pressures up to about 37 MPa. A spectral analysis of the transmitted pulse reveals that the flexural, extensional, thickness-shear, and radial plate modes are excited into vibration, but none of these appears to be significantly affected by the pressurization of the liquid.

  6. Strong environmental tolerance of moss Venturiella under very high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ono, F; Mori, Y; Takarabe, K [Department of Applied Science, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005 (Japan); Nishihira, N; Shindo, A [Okayama Ichinomiya High School, Okayama 700-0005 (Japan); Saigusa, M [Department of Biology, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Matsushima, Y [Department of Physics, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Saini, N L [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185 Rome (Italy); Yamashita, M, E-mail: [Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)


    It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25{sup 0}C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

  7. Pulsed laser kinetic studies of liquids under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Eyring, E.M.


    A high pressure apparatus constructed for measuring the rates of reactions in liquids under pressures ranging from 1 atm to 2000 atm has been used to measure the complexation kinetics of molybdenum hexacarbonyl reacting with 2,2-bipyridine, 4,4{prime}-dimethyl-2-2{prime}-bipyridine and 4,4{prime}-diphenyl-2-2{prime} bipyridine in toluene. Pentacarbonyl reaction intermediates are created by a 10 nsec flash of frequency tripled Nd:YAG laser light. Measured activation volumes for chelate ligand ring closure indicate a change in mechanism from associative interchange to dissociative interchange as steric hindrance increases. A similar high pressure kinetics study of molybdenum carbonyl complexation by several substituted phenanthrolines is now well advanced that indicates that with the more rigid phenanthroline ligands steric effects from bulky substituents have less effect on the ring closure mechanism than in the case of the bipyridine ligands. An experimental concentration dependence of the fluorescence quantum yield of cresyl violet has been harmonized with previously published contradictory reports. Fluorescence of cresyl violet in various solvents and in micellar systems has also been systematically explored.

  8. Thermal and high pressure inactivation kinetics of blueberry peroxidase. (United States)

    Terefe, Netsanet Shiferaw; Delon, Antoine; Versteeg, Cornelis


    This study for the first time investigated the stability and inactivation kinetics of blueberry peroxidase in model systems (McIlvaine buffer, pH=3.6, the typical pH of blueberry juice) during thermal (40-80°C) and combined high pressure-thermal processing (0.1-690MPa, 30-90°C). At 70-80°C, the thermal inactivation kinetics was best described by a biphasic model with ∼61% labile and ∼39% stable fractions at temperature between 70 and 75°C. High pressure inhibited the inactivation of the enzyme with no inactivation at pressures as high as 690MPa and temperatures less than 50°C. The inactivation kinetics of the enzyme at 60-70°C, and pressures higher than 500MPa was best described by a first order biphasic model with ∼25% labile fraction and 75% stable fraction. The activation energy values at atmospheric pressure were 548.6kJ/mol and 324.5kJ/mol respectively for the stable and the labile fractions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  9. Predicting human blood viscosity in silico (United States)

    Fedosov, Dmitry A.; Pan, Wenxiao; Caswell, Bruce; Gompper, Gerhard; Karniadakis, George E.


    The viscosity of blood has long been used as an indicator in the understanding and treatment of disease, and the advent of modern viscometers allows its measurement with ever-improving clinical convenience. However, these advances have not been matched by theoretical developments that can yield a quantitative understanding of blood’s microrheology and its possible connection to relevant biomolecules (e.g., fibrinogen). Using coarse-grained molecular dynamics and two different red blood cell models, we accurately predict the dependence of blood viscosity on shear rate and hematocrit. We explicitly represent cell–cell interactions and identify the types and sizes of reversible rouleaux structures that yield a tremendous increase of blood viscosity at low shear rates. We also present the first quantitative estimates of the magnitude of adhesive forces between red cells. In addition, our simulations support the hypothesis, previously deduced from experiments, of yield stress as an indicator of cell aggregation. This non-Newtonian behavior is analyzed and related to the suspension’s microstructure, deformation, and dynamics of single red blood cells. The most complex cell dynamics occurs in the intermediate shear rate regime, where individual cells experience severe deformation and transient folded conformations. The generality of these cell models together with single-cell measurements points to the future prediction of blood-viscosity anomalies and the corresponding microstructures associated with various diseases (e.g., malaria, AIDS, and diabetes mellitus). The models can easily be adapted to tune the properties of a much wider class of complex fluids including capsule and vesicle suspensions. PMID:21730178

  10. Microbial Evolution at High Pressure: Deep Sea and Laboratory Studies (United States)

    Bartlett, D. H.


    Elevated hydrostatic pressures are present in deep-sea and deep-Earth environments where this physical parameter has influenced the evolution and characteristics of life. Piezophilic (high-pressure-adapted) microbes have been isolated from diverse deep-sea settings, and would appear likely to occur in deep-subsurface habitats as well. In order to discern the factors enabling life at high pressure my research group has explored these adaptations at various levels, most recently including molecular analyses of deep-sea trench communities, and through the selective evolution of the model microbe Escherichia coli in the laboratory to progressively higher pressures. Much of the field work has focused on the microbes present in the deeper portions of the Puerto Rico Trench (PRT)and in the Peru-Chile Trench (PCT), from 6-8.5 km below the sea surface (~60-85 megapascals pressure). Culture-independent phylogenetic data on the Bacteria and Archaea present on particles or free-living, along with data on the microeukarya present was complemented with genomic analyses and the isolation and characterization of microbes in culture. Metagenomic analyses of the PRT revealed increased genome sizes and an overrepresentation at depth of sulfatases for the breakdown of sulfated polysaccharides and specific categories of transporters, including those associated with the transport of diverse cations or carboxylate ions, or associated with heavy metal resistance. Single-cell genomic studies revealed several linneages which recruited to the PRT metagenome far better than existing marine microbial genome sequences. analyses. Novel high pressure culture approaches have yielded new piezophiles including species preferring very low nutrient levels, those living off of hydrocarbons, and those adapted to various electron donor/electron acceptor combinations. In order to more specifically focus on functions enabling life at increased pressure selective evolution experiments were performed with

  11. Microhole High-Pressure Jet Drill for Coiled Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Ken Theimer; Jack Kolle


    Tempress Small Mechanically-Assisted High-Pressure Waterjet Drilling Tool project centered on the development of a downhole intensifier (DHI) to boost the hydraulic pressure available from conventional coiled tubing to the level required for high-pressure jet erosion of rock. We reviewed two techniques for implementing this technology (1) pure high-pressure jet drilling and (2) mechanically-assisted jet drilling. Due to the difficulties associated with modifying a downhole motor for mechanically-assisted jet drilling, it was determined that the pure high-pressure jet drilling tool was the best candidate for development and commercialization. It was also determined that this tool needs to run on commingled nitrogen and water to provide adequate downhole differential pressure and to facilitate controlled pressure drilling and descaling applications in low pressure wells. The resulting Microhole jet drilling bottomhole assembly (BHA) drills a 3.625-inch diameter hole with 2-inch coil tubing. The BHA consists of a self-rotating multi-nozzle drilling head, a high-pressure rotary seal/bearing section, an intensifier and a gas separator. Commingled nitrogen and water are separated into two streams in the gas separator. The water stream is pressurized to 3 times the inlet pressure by the downhole intensifier and discharged through nozzles in the drilling head. The energy in the gas-rich stream is used to power the intensifier. Gas-rich exhaust from the intensifier is conducted to the nozzle head where it is used to shroud the jets, increasing their effective range. The prototype BHA was tested at operational pressures and flows in a test chamber and on the end of conventional coiled tubing in a test well. During instrumented runs at downhole conditions, the BHA developed downhole differential pressures of 74 MPa (11,000 psi, median) and 90 MPa (13,000 psi, peaks). The median output differential pressure was nearly 3 times the input differential pressure available from the

  12. Comparison of Parallel Viscosity with Neoclassical Theory


    K., Ida; N., Nakajima


    Toroidal rotation profiles are measured with charge exchange spectroscopy for the plasma heated with tangential NBI in CHS heliotron/torsatron device to estimate parallel viscosity. The parallel viscosity derived from the toroidal rotation velocity shows good agreement with the neoclassical parallel viscosity plus the perpendicular viscosity. (mu_perp =2m^2 /s).

  13. Experimental apparatus for measurement of density of supercooled water at high pressure

    Directory of Open Access Journals (Sweden)

    Peukert Pavel


    Full Text Available Thermodynamic behavior of supercooled water (metastable fluid water existing transiently below the equilibrium freezing point at high pressures was subject to many recent theoretical studies. Some of them assume that a second critical point of water exists, related to two liquid phases of supercooled water: the low-density liquid and the high-density liquid. To test these theories, an original experimental cryogenic apparatus is being developed. The volume changes are measured optically in custom-treated fused-silica capillary tubes. The capillaries are placed in a metal vessel designed for pressures up to 200 MPa. The vessel is connected to a circulation thermostat enabling a rapid change of temperature to prevent freezing. A new high-vacuum device was developed for degassing of the ultrapure water sample and filling it into the measuring capillaries. The experiments will contribute to fundamental understanding of the anomalous behavior of water and to applications in meteorology, aerospace engineering, cryobiology etc.

  14. High pressure fracturing in Colombia: a quantum leap

    Energy Technology Data Exchange (ETDEWEB)

    Velasquez, Juan C. [BP Exploration (United Kingdom); Gutierrez, Jim; Ham, Ernesto; Castro, Alberto [BJ Services Company (United States)


    Fracturing has become one of the most common stimulation and well completion techniques in petroleum production. Due to the deeper depths and high frac gradients encountered in some areas, various treatments have resulted in early screen outs or aborted operations due to insufficient rate limited by the available treating pressures. A state of the art technology and high pressure equipment including the largest frac pumps (rated at 2,700 hhp) in the world, were used in Colombian fields to overcome these limitations. The reliability of this equipment has allowed the treatment of these wells to operating pressures of up to 18,000 psi and rates in excess of 40 bpm, placing up to 400,000 lbs of bauxite. Bottom hole treating pressures of 25,000 psi also were reached. This paper describes the development of the fracture campaign and relates the jobs performed to date, including the results and lessons learned (author)

  15. Linear ruby scale and one megabar. [high pressure fluorescence (United States)

    Ruoff, A. L.


    The accuracy and validity of certain techniques used in studying high-pressure transitions have been investigated. Experiments which place upper limits of about 20 GPa and about 50 GPa on pressures practically attainable using uniaxial supported opposed anvil devices with tungsten carbide pistons and uniaxial opposed flat anvil diamond devices, respectively, are reported. Direct static determinations of the transition pressures of GaP by two different methods are described. The values obtained indicate that the linear ruby scale increasingly overestimates the transition pressure as the pressure rises above 10 GPa. It is further shown that the use of shock-based marker materials, such as silver, as the basis of pressure measurement in X-ray diffraction studies leads to bulk moduli of cubic carbides which are in extreme disagreement with expected values.

  16. A stable compound of helium and sodium at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xiao; Oganov, Artem R.; Goncharov, Alexander F.; Stavrou, Elissaios; Lobanov, Sergey; Saleh, Gabriele; Qian, Guang-Rui; Zhu, Qiang; Gatti, Carlo; Deringer, Volker L.; Dronskowski, Richard; Zhou, Xiang-Feng; Prakapenka, Vitali B.; Konôpková, Zuzana; Popov, Ivan A.; Boldyrev, Alexander I.; Wang, Hui-Tian


    Helium is generally understood to be chemically inert and this is due to its extremely stable closed-shell electronic configuration, zero electron affinity and an unsurpassed ionization potential. It is not known to form thermodynamically stable compounds, except a few inclusion compounds. Here, using the ab initio evolutionary algorithm USPEX and subsequent high-pressure synthesis in a diamond anvil cell, we report the discovery of a thermodynamically stable compound of helium and sodium, Na2He, which has a fluorite-type structure and is stable at pressures >113 GPa. We show that the presence of He atoms causes strong electron localization and makes this material insulating. This phase is an electride, with electron pairs localized in interstices, forming eight-centre two-electron bonds within empty Na8 cubes. We also predict the existence of Na2HeO with a similar structure at pressures above 15 GPa.

  17. The high-pressure phase of CePtAl

    Energy Technology Data Exchange (ETDEWEB)

    Heymann, Gunter [Univ. Innsbruck (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Heying, Birgit; Rodewald, Ute C. [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Univ. Oldenburg (Germany). Inst. fuer Chemie


    The intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn{sub 2}-type structure (P6{sub 3}/mmc) with lattice parameters of a=552.7(1) and c=898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations (wR=0.0527, 187 F{sup 2} values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.

  18. Ferrous alloys cast under high pressure gas atmosphere

    Directory of Open Access Journals (Sweden)

    Pirowski Z.


    Full Text Available The main objective of this paper is describing the essence of the process of introducing nitrogen to the melt of ferrous alloys by application of overpressure above the metal bath. The problem was discussed in terms of both theory (the thermodynamic aspects of the process and practice (the technical and technological aspects, safety of the furnace stand operation, and technique of conducting the melt. The novel technique of melting under high pressure of the gas atmosphere (up to 5 MPa has not been used so far in the domestic industry, mainly because of the lack of proper equipment satisfyng the requirements of safe operation. Owing to cooperation undertaken with a partner from Bulgaria, a more detailed investigation of this technology has become possible and melting of selected ferrous alloys was conducted under the gas atmosphere at a pressure of about 3,5 MPa.

  19. Structural Phase Transition of ThC Under High Pressure. (United States)

    Yu, Cun; Lin, Jun; Huai, Ping; Guo, Yongliang; Ke, Xuezhi; Yu, Xiaohe; Yang, Ke; Li, Nana; Yang, Wenge; Sun, Baoxing; Xie, Ruobing; Xu, Hongjie


    Thorium monocarbide (ThC) as a potential fuel for next generation nuclear reactor has been subjected to its structural stability investigation under high pressure, and so far no one reported the observation of structure phase transition induced by pressure. Here, utilizing the synchrotron X-ray diffraction technique, we for the first time, experimentally revealed the phase transition of ThC from B1 to P4/nmm at pressure of ~58 GPa at ambient temperature. A volume collapse of 10.2% was estimated during the phase transition. A modulus of 147 GPa for ThC at ambient pressure was obtained and the stoichiometry was attributed to the discrepancy of this value to the previous reports.

  20. High pressure synthesis of BiS2

    DEFF Research Database (Denmark)

    Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

    crystal structures and electrical properties.1,2 Up until now, the most sulfur rich phase in the Bi-S phase diagram was Bi2S3.3 For BiS2 the Bi atoms have anisotropic charge distribution and more complex structures are expected when comparing the layered structures of transition metal dichalcogenides....... The possibilities of using high pressure synthesis to discover new phases in the Bi-S binary system were investigated as early as the 1960’s.4 The research led to discovery of a compound with BiS2 stoichiometry, but no structure solution of BiS2 was reported. A reason behind making this new phase is to study...

  1. High-Pressure Die-Casting: Contradictions and Challenges (United States)

    Bonollo, Franco; Gramegna, Nicola; Timelli, Giulio


    High-pressure die casting (HPDC) is particularly suitable for high production rates and it is applied in several industrial fields; actually, approximately half of the world production of light metal castings is obtained by this technology. An overview of the actual status of HPDC technology is described in the current work, where both critical aspects and potential advantages are evidenced. Specific attention is paid to the quality requirements from the end users, as well as to the achievable production rate, the process monitoring and control, and the European and worldwide scenario. This overview leads to individuate the most relevant challenges for HPDC industry: "zero-defect" production, real-time process control, understanding the role of the process variables, process optimization, introduction of research and development activities, and disseminating the knowledge about HPDC technology. Performing these actions, HPDC foundries could achieve a more mature and efficient approach to large end users and exploit their really relevant potential.

  2. Prediction of Surface Porosity Defects in High Pressure Die Casting (United States)

    Saeedipour, Mahdi; Schneiderbauer, Simon; Pirker, Stefan; Bozorgi, Salar

    High pressure die casting (HPDC) is a novel manufacturing method with capability of mass production with higher accuracy. Porosity is one of the challenging defects in final product and may be affected by jet instability and atomization during injection phase. In case of atomization a large number of droplets with high velocity impinges the colder confining walls of the casting mold and might solidify consecutively. Different time scales of the impingement of the droplets and their solidification may result in heterogeneous structures near the surface of final product. A numerical framework using volume of fluid method (VOF) and an Eulerian-Lagrangian approach is established to simulate the liquid metal jet breakup and droplet formation during the injection phase. An analytical model for droplet impact on mold walls and solidification is studied and implemented in the numerical framework. The latter enables the prediction of porosity formation near the surface of final product.

  3. Monitoring of High Pressure with Fiber Optic Sensor

    Directory of Open Access Journals (Sweden)

    Pandey N.K.


    Full Text Available Paper reports intensity modulated pressure sensor using microbending in the optical fiber embedded in the structural material. Pressure induced microbends have been created in silica clad graded index multimode optical fiber 50mm, plastic clad PCS200 and plastic clad PCS600 optical fibers embedded in the sample of araldite matrix. The samples have been tested separately with random microbending and periodic microbending of spatial periodicity Λ=5mm under high pressure cyclic loading conditions. The maximum pressure measured with PCS600 is 3.0 MPa, with PCS200 the maximum pressure measured is 1.8 MPa and that with silica clad 50mm maximum pressure measured is 1.6 MPa. The results with PCS600 optical fiber have been found to be linear and most reliable.

  4. High pressure Raman spectra of monoglycine nitrate single crystal (United States)

    Carvalho, J. O.; Moura, G. M.; Dos Santos, A. O.; Lima, R. J. C.; Freire, P. T. C.; Façanha Filho, P. F.


    Single crystal of monoglycine nitrate has been studied by Raman spectroscopy under high pressures up to 5.5 GPa. The results show changes in lattice modes in the pressure ranges of 1.1-1.6 GPa and 4.0-4.6 GPa. The first change occurs with appearance of bands related to the lattice modes as well as discontinuity in the slope of dΩ/dP of these modes. Moreover, bands associated with the skeleton of glycine suggest that the molecule undergoes conformational modifications. The appearance of a strong band at 55 cm- 1 point to a second phase transition associated with the lattice modes, while the internal modes remain unchanged. These anomalies are probably due to rearrangement of hydrogen bonds. Additionally, decompression to ambient pressure shows that the phase transitions are reversible. Finally, the results show that the nitrate anions play an important role on the stability of the monoglycine nitrate crystal.

  5. High pressure, high current, low inductance, high reliability sealed terminals (United States)

    Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN


    The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

  6. Small, high pressure ratio compressor: Aerodynamic and mechanical design (United States)

    Bryce, C. A.; Erwin, J. R.; Perrone, G. L.; Nelson, E. L.; Tu, R. K.; Bosco, A.


    The Small, High-Pressure-Ratio Compressor Program was directed toward the analysis, design, and fabrication of a centrifugal compressor providing a 6:1 pressure ratio and an airflow rate of 2.0 pounds per second. The program consists of preliminary design, detailed areodynamic design, mechanical design, and mechanical acceptance tests. The preliminary design evaluate radial- and backward-curved blades, tandem bladed impellers, impeller-and diffuser-passage boundary-layer control, and vane, pipe, and multiple-stage diffusers. Based on this evaluation, a configuration was selected for detailed aerodynamic and mechanical design. Mechanical acceptance test was performed to demonstrate that mechanical design objectives of the research package were met.

  7. Development of a remote inspection robot for high pressure structures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae C.; Kim, Jae H.; Choi, Yu R.; Moon, Soon S


    The high pressure structures in industrial plants must be periodically inspected for ensure their safety. Currently, the examination of them is manually performed by human inspectors, and there are many restrictions to examine the large containers which enclose dangerous chemicals or radioactive materials. We developed a remotely operated robot to examine these structures using recent mobile robot and computer technologies. Our robot has two magnetic caterpillars that make the robot can adhere to the structures made of steel like materials. The robot moves to the position for examination, and scans that position using ultrasonic probes equipped on it's arm, and transmits the result to the inspector according to his/her commands. Without building any auxiliary structures the robot can inspect the places where manual inspection can't reach. Therefore the robot can make shortening the inspection time as well as preventing the inspector from an accident. (author)

  8. Strong environmental tolerance of Artemia under very high pressure (United States)

    Minami, K.; Ono, F.; Mori, Y.; Takarabe, K.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.


    It was shown by the present authors group that a tardigrade in its tun-state can survive after exposed to 7.5 GPa for 13 hours. We have extended this experiment to other tiny animals searching for lives under extreme conditions of high hydrostatic pressure. Artemia, a kind of planktons, in its dried egg-state have strong environmental tolerance. Dozens of Artemia eggs were sealed in a small Teflon capsule together with a liquid pressure medium, and exposed to the high hydrostatic pressure of 7.5 GPa. After the pressure was released, they were soaked in seawater to observe hatching rate. It was proved that 80-90% of the Artemia eggs were alive and hatched into Nauplii after exposed to the maximum pressure of 7.5 GPa for up to 48 hours. Comparing with Tardigrades, Artemia are four-times stronger against high pressure.

  9. High pressure structural phase transitions of PbPo

    Energy Technology Data Exchange (ETDEWEB)

    Bencherif, Y.; Boukra, A. [Departement de Physique, Faculte des Sciences, Universite de Mostaganem (Algeria); Departement de Physique, Universite des Sciences et de la Technologie d' Oran, USTO, Oran (Algeria); Zaoui, A., E-mail: [Universite Lille Nord de France, LGCgE (EA 4515) Lille1, Polytech' Lille, Cite Scientifique, Avenue Paul Langevin, 59655 Villeneuve D' Ascq Cedex (France); Ferhat, M. [Departement de Physique, Universite des Sciences et de la Technologie d' Oran, USTO, Oran (Algeria)


    First-principles calculations have been performed to investigate the high pressure phase transitions and dynamical properties of the less known lead polonium compound. The calculated ground state parameters for the NaCl phase show good agreement with the experimental data. The obtained results show that the intermediate phase transition for this compound is the orthorhombic Pnma phase. The PbPo undergoes from the rocksalt to Pnma phase at 4.20 GPa. Further structural phase transition from intermediate to CsCl phase has been found at 8.5 GPa. In addition, phonon dispersion spectra were derived from linear-response to density functional theory. In particular, we show that the dynamical properties of PbPo exhibit some peculiar features compared to other III-V compounds. Finally, thermodynamics properties have been also addressed from quasiharmonic approximation.

  10. Color changes in pork in relation to high pressure treatment

    DEFF Research Database (Denmark)

    Bak, Kathrine Holmgaard

    that the critical limit of O2 is higher for dry-cured meat than for cooked, cured meat, possibly due to the reduced molecular mobility in the drier samples. HP treatment appeared to offer an additional protective effect to surface color stability in dry-cured meat, possibly by introducing intermolecular hydrogen......The color changes taking place in fresh as well as cured pork as a result of high pressure (HP) treatment were investigated, characterized, and explained. The effect of HP in the range from 200 through 800 MPa at 5 °C or 20°C on the color of fresh porcine longissimus dorsi (LD) immediately after HP...... treatment and during a six-day storage period was investigated via surface reflectance. Spectroscopic studies (in the form of surface reflectance, UV-vis, and circular dichroism) on the effect of HP treatment on the soluble protein fraction of porcine LD were conducted attempting to explain the color...

  11. Topological signature in the NEXT high pressure xenon TPC (United States)

    Ferrario, Paola; NEXT Collaboration


    The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qββ as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 ± 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 ± 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% ± 0.6% background acceptance for 66.9% ± 0.6% signal efficiency.

  12. NATO Advanced Study Institute on High-Pressure Crystallography

    CERN Document Server

    Boldyreva, Elena; High-Pressure Crystallography


    This book is devoted to the theme of crystallographic studies at high pressure, with emphasis on the phenomena characteristic to the compressed state of matter, as well as experimental and theoretical techniques used to study these phenomena. As a thermodynamic parameter, pressure is remarkable in many ways. In the visible universe its value spans over sixty orders of magnitude, from the non-equilibrium pressure of hydrogen in intergalactic space, to the kind of pressure encountered within neutron stars. In the laboratory, it provides the unique possibility to control the structure and properties of materials, to dramatically alter electronic properties, and to break existing, or form new chemical bonds. This agenda naturally encompasses elements of physics (properties, structure and transformations), chemistry (reactions, transport), materials science (new materials) and engineering (mechanical properties); in addition it has direct applications and implications for geology (minerals in deep Earth environmen...

  13. High-pressure Brillouin study on methane hydrate

    CERN Document Server

    Sasaki, S; Suwa, I; Kume, T; Shimizu, H


    Acoustic velocities and adiabatic elastic constants of structure I of methane hydrate (MH) have been determined as a function of pressure up to 0.6 GPa at 23 deg. C by the high-pressure Brillouin spectroscopy developed for a single molecular crystal. The pressure dependence of the acoustic velocities of MH is very similar to that of ice-Ih except for the longitudinal acoustic (LA) velocity. The value of the LA velocity along the (100) direction of MH at 0.02 GPa is 3.63 km s sup - sup 1 which is about 7% lower than the average of the LA velocities in the ice-Ih phase at -35.5 deg. C and atmospheric pressure.

  14. NEXT: Neutrino Experiment with high pressure Xenon gas TPC

    Energy Technology Data Exchange (ETDEWEB)

    Yahlali, Nadia, E-mail: Nadia.Yahlali@ific.uv.e [Instituto de Fisica Corpuscular (Centro mixto UV-CSIC), Apdo. de Correos 22085, E-46071 Valencia (Spain); Ball, M.; Carcel, S.; Diaz, J.; Gil, A.; Gomez Cadenas, J.J.; Martin-Albo, J.; Monrabal, F.; Serra, L.; Sorel, M. [Instituto de Fisica Corpuscular (Centro mixto UV-CSIC), Apdo. de Correos 22085, E-46071 Valencia (Spain)


    The search of the neutrinoless double-{beta} decay address the major Physics goals of revealing the nature of the neutrino and setting an absolute scale for its mass. The observation of a positive {beta}{beta}{sup 0{nu}}signal, the unique signature of Majorana neutrinos, would have deep consequences in particle physics and cosmology. Therefore, any claim of observing a positive signal shall require extremely robust evidences. NEXT is a new double-{beta} experiment which aims at building a 100 kg high pressure {sup 136}Xe gas TPC, to be hosted in the Canfranc Underground Laboratory (LSC), in Spain. This paper address the novel design concept of NEXT TPC believed to provide a pathway for an optimized and robust double-{beta} experiment.

  15. Study on the Radial Diffuser of Multistage High Pressure Pump

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Deok Su; Mamatov, Sanjar [Hyosung goodsprings inc, Seoul (Korea, Republic of); Park, Warn Gyu [Pusan Nat’l Univ., Busan (Korea, Republic of)


    In this study, a high-pressure multistage pump used in the combined cycle power plants is analyzed. The pump performance characteristics (differential head and efficiency) are numerically analyzed for different shapes of the radial diffuser. The design variables selected for the radial diffuser are, number of vanes, diameter ratio (D{sub 4}/D{sub 3}), return channel outlet angle(α{sub 6}), and pressure recovery factor (C{sub p}). The numerical analysis results showed that the differential head and efficiency are the highest when the diameter ratio is the highest. Further, it was observed that the differential head was lower when the return channel outlet angle was 60° than when it was 90°, because of pre-swirl at the diffuser outlet.

  16. High-Pressure Synthesis of a Pentazolate Salt

    Energy Technology Data Exchange (ETDEWEB)

    Steele, Brad A.; Stavrou, Elissaios; Crowhurst, Jonathan C.; Zaug, Joseph M.; Prakapenka, Vitali B.; Oleynik, Ivan I.


    The pentazolates, the last all-nitrogen members of the azole series, have been notoriously elusive for the last hundred years despite enormous efforts to make these compounds in either gas or condensed phases. Here, we report a successful synthesis of a solid state compound consisting of isolated pentazolate anions N5–, which is achieved by compressing and laser heating cesium azide (CsN3) mixed with N2 cryogenic liquid in a diamond anvil cell. The experiment was guided by theory, which predicted the transformation of the mixture at high pressures to a new compound, cesium pentazolate salt (CsN5). Electron transfer from Cs atoms to N5 rings enables both aromaticity in the pentazolates as well as ionic bonding in the CsN5 crystal. This work provides critical insight into the role of extreme conditions in exploring unusual bonding routes that ultimately lead to the formation of novel high nitrogen content species.

  17. Combination of endolysins and high pressure to inactivate Listeria monocytogenes. (United States)

    van Nassau, Tomas J; Lenz, Christian A; Scherzinger, Anna S; Vogel, Rudi F


    Outbreaks of listeriosis are often related to the consumption of low-processed ready-to-eat food products (e.g. soft cheeses or smoked fish) contaminated with Listeria monocytogenes. Traditional preservation techniques, such as heat treatment, cannot eliminate Listeria from these products without strongly affecting the quality of the foods. We therefore investigated the use of endolysin (PlyP40, Ply511, or PlyP825) in combination with high hydrostatic pressure processing to kill L. monocytogenes in buffer. The results demonstrated a more than additive effect when both treatments were combined. For example, whereas 0.16 μg/mL PlyP825 or 300 MPa (1 min, 30 °C) applied individually reduced the cell count by 0.2 and 0.3 log cfu, respectively, a combined treatment resulted in a reduction of 5.5 log cfu. Similar results were obtained for the other endolysins combined with high pressure processing. We also showed that the synergistic inactivation of cells by endolysin and HHP is possible at a pressure level of only 200 MPa (2 min, 30 °C). Thus, the application of endolysins did not only substantially increase the bactericidal effect of high pressure, but it also enabled the inactivation of bacterial cells at much lower pressure levels. This shows the potential of using such combined processes for the inactivation of L. monocytogenes and food preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Simulation of phase separation with temperature-dependent viscosity using lattice Boltzmann method. (United States)

    Wang, Heping; Zang, Duyang; Li, Xiaoguang; Geng, Xingguo


    This paper presents an exploration of the phase separation behavior and pattern formation in a binary fluid with temperature-dependent viscosity via a coupled lattice Boltzmann method (LBM). By introducing a viscosity-temperature relation into the LBM, the coupling effects of the viscosity-temperature coefficient [Formula: see text] , initial viscosity [Formula: see text] and thermal diffusion coefficient [Formula: see text] , on the phase separation were successfully described. The calculated results indicated that an increase in initial viscosity and viscosity-temperature coefficient, or a decrease in the thermal diffusion coefficient, can lead to the orientation of isotropic growth fronts over a wide range of viscosity. The results showed that droplet-type phase structures and lamellar phase structures with domain orientation parallel or perpendicular to the walls can be obtained in equilibrium by controlling the initial viscosity, thermal diffusivity, and the viscosity-temperature coefficient. Furthermore, the dataset was rearranged for growth kinetics of domain growth and thermal diffusion fronts in a plot by the spherically averaged structure factor and the ratio of separated and continuous phases. The analysis revealed two different temporal regimes: spinodal decomposition and domain growth stages, which further quantified the coupled effects of temperature and viscosity on the evolution of temperature-dependent phase separation. These numerical results provide guidance for setting optimum temperature ranges to obtain expected phase separation structures for systems with temperature-dependent viscosity.

  19. Viscosity kernel of molecular fluids

    DEFF Research Database (Denmark)

    Puscasu, Ruslan; Todd, Billy; Daivis, Peter


    The wave-vector dependent shear viscosities for butane and freely jointed chains have been determined. The transverse momentum density and stress autocorrelation functions have been determined by equilibrium molecular dynamics in both atomic and molecular hydrodynamic formalisms. The density......, temperature, and chain length dependencies of the reciprocal and real-space viscosity kernels are presented. We find that the density has a major effect on the shape of the kernel. The temperature range and chain lengths considered here have by contrast less impact on the overall normalized shape. Functional...... forms that fit the wave-vector-dependent kernel data over a large density and wave-vector range have also been tested. Finally, a structural normalization of the kernels in physical space is considered. Overall, the real-space viscosity kernel has a width of roughly 3–6 atomic diameters, which means...

  20. Viscosity Control Experiment Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Heidi E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bradley, Paul Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    Turbulent mix has been invoked to explain many results in Inertial Confinement Fusion (ICF) and High Energy Density (HED) physics, such as reduced yield in capsule implosions. Many ICF capsule implosions exhibit interfacial instabilities seeded by the drive shock, but it is not clear that fully developed turbulence results from this. Many simulations use turbulent mix models to help match simulation results to data, but this is not appropriate if turbulence is not present. It would be useful to have an experiment where turbulent mixing could be turned on or off by design. The use of high-Z dopants to modify viscosity and the resulting influence on turbulence is considered here. A complicating factor is that the plasma in some implosions can become strongly coupled, which makes the Spitzer expression for viscosity invalid. We first consider equations that cover a broad parameter space in temperature and density to address regimes for various experimental applications. Next, a previous shock-tube and other ICF experiments that investigate viscosity or use doping to examine the effects on yield are reviewed. How viscosity and dopants play a role in capsule yield depends on the region and process under consideration. Experiments and simulations have been performed to study the effects of viscosity on both the hot spot and the fuel/ablator mix. Increases in yield have been seen for some designs, but not all. We then discuss the effect of adding krypton dopant to the gas region of a typical OMEGA and a 2-shock NIF implosion to determine approximately the effect of adding dopant on the computed Reynolds number. Recommendations for a path forward for possible experiments using high-Z dopants to affect viscosity and turbulence are made.

  1. Human capability in the perception of extensional and shear viscosity. (United States)

    Lv, Zhihong; Chen, Jianshe; Holmes, Melvin


    Shear and extensional deformation are two basic rheological phenomena which occur commonly in our daily life. Because of the very different nature of the two deformations, fluid materials may exhibit significant differences in their responses to shear and extensional forces. This work investigated the human perception of shear and extensional viscosity and tested the hypothesis that human have different discriminatory sensation mechanisms including scaling to the two deformations. A series of fluid samples were prepared using two common food thickeners, guar gum and sodium carboxylmethylcellulose (CMC-Na). The shear and extensional flow behavior of these fluids were assessed using shear and extensional rheometers and in addition two separate sensory analysis sessions were organized to assess human sensitivity in perceiving the two viscosities. Magnitude estimation was used in the first session to assess human sensitivity in the perception of the shear and extensional viscosities and just-noticeable-difference (JND) assessment was used for the second session to identify the typical threshold of viscosity discrimination. For the participants considered, it was found that the perception of both shear and extensional viscosity follow a power law relationship i.e. Steven's law. It was also observed that the human has a greater discriminatory capacity in perceiving extensional viscosity. JND analysis showed that the human threshold in detecting shear viscosity difference was 9.33%, but only 6.20% for extensional viscosity. Shear and extensional deformation are two basic rheological properties which occur during food manipulation, mastication, deglutition executed during oral consumption and also in the processing and packaging of foods. Fluid resistance against shear and extensional deformation differ widely and whilst this has been confirmed theoretically and experimentally, a clear understanding of human perception of these properties will have beneficial returns to

  2. Microstructure of calcite deformed by high-pressure torsion: An X-ray line profile study (United States)

    Schuster, Roman; Schafler, Erhard; Schell, Norbert; Kunz, Martin; Abart, Rainer


    Calcite aggregates were deformed to high strain using high-pressure torsion and applying confining pressures of 1-6 GPa and temperatures between room temperature and 450 °C. The run products were characterized by X-ray diffraction, and key microstructural parameters were extracted employing X-ray line profile analysis. The dominant slip system was determined as r { 10 1 bar 4 } ⟨ 2 bar 021 ⟩ with edge dislocation character. The resulting dislocation density and the size of the coherently scattering domains (CSD) exhibit a systematic dependence on the P-T conditions of deformation. While high pressure generally impedes recovery through reducing point defect mobility, the picture is complicated by pressure-induced phase transformations in the CaCO3 system. Transition from the calcite stability field to those of the high-pressure polymorphs CaCO3-II, CaCO3-III and CaCO3-IIIb leads to a change of the microstructural evolution with deformation. At 450 °C and pressures within the calcite stability field, dislocation densities and CSD sizes saturate at shear strains exceeding 10 in agreement with earlier studies at lower pressures. In the stability field of CaCO3-II, the dislocation density exhibits a more complex behavior. Furthermore, at a given strain and strain rate, the dislocation density increases and the CSD size decreases with increasing pressure within the stability fields of either calcite or of the high-pressure polymorphs. There is, however, a jump from high dislocation densities and small CSDs in the upper pressure region of the calcite stability field to lower dislocation densities and larger CSDs in the low-pressure region of the CaCO3-II stability field. This jump is more pronounced at higher temperatures and less so at room temperature. The pressure influence on the deformation-induced evolution of dislocation densities implies that pressure variations may change the rheology of carbonate rocks. In particular, a weakening is expected to occur at

  3. Unraveling Crystalline Structure of High-Pressure Phase of Silicon Carbonate

    Directory of Open Access Journals (Sweden)

    Rulong Zhou


    Full Text Available Although CO_{2} and SiO_{2} both belong to group-IV oxides, they exhibit remarkably different bonding characteristics and phase behavior at ambient conditions. At room temperature, CO_{2} is a gas, whereas SiO_{2} is a covalent solid with rich polymorphs. A recent successful synthesis of the silicon-carbonate solid from the reaction between CO_{2} and SiO_{2} under high pressure [M. Santoro et al., Proc. Natl. Acad. Sci. U.S.A. 108, 7689 (2011] has resolved a long-standing puzzle regarding whether a Si_{x}C_{1−x}O_{2} compound between CO_{2} and SiO_{2} exists in nature. Nevertheless, the detailed atomic structure of the Si_{x}C_{1−x}O_{2} crystal is still unknown. Here, we report an extensive search for the high-pressure crystalline structures of the Si_{x}C_{1−x}O_{2} compound with various stoichiometric ratios (SiO_{2}:CO_{2} using an evolutionary algorithm. Based on the low-enthalpy structures obtained for each given stoichiometric ratio, several generic structural features and bonding characteristics of Si and C in the high-pressure phases are identified. The computed formation enthalpies show that the SiC_{2}O_{6} compound with a multislab three-dimensional (3D structure is energetically the most favorable at 20 GPa. Hence, a stable crystalline structure of the elusive Si_{x}C_{1−x}O_{2} compound under high pressure is predicted and awaiting future experimental confirmation. The SiC_{2}O_{6} crystal is an insulator with elastic constants comparable to typical hard solids, and it possesses nearly isotropic tensile strength as well as extremely low shear strength in the 2D plane, suggesting that the multislab 3D crystal is a promising solid lubricant. These valuable mechanical and electronic properties endow the SiC_{2}O_{6} crystal for potential applications in tribology and nanoelectronic devices, or as a stable solid-state form for CO_{2} sequestration.

  4. Metallization and softening of B{sub 6}O at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuehui [Institute of Physics and Chemistry, HNUST, Qinhuangdao, Hebei 066600 (China); Wang, Yachun; Yao, Tiankai; Li, Hui; Wu, Lailei; Yang, Meng [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhang, Jingwu, E-mail: [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Gou, Huiyang, E-mail: [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)


    Highlights: • Structural searching identified a high-pressure phase for B{sub 6}O with monoclinic Cc structure. • Cc structure B{sub 6}O is mechanically and dynamically stable. • Cc phase characterizes in pentagonal pyramids and zig-zag O–B1–O chains. • Cc phase shows metallization and softened hardness as compared to zero-pressure structure. - Abstract: Structural stability, elastic and electronic properties of boron suboxide, B{sub 6}O, up to 300 GPa were investigated by first-principles calculations. Structural searching and enthalpy differences calculations identify a high-pressure phase for B{sub 6}O with monoclinic Cc structure (denoted as β-B{sub 6}O), which is energetically preferable to the known R-3 m-type phase above 245 GPa. β-B{sub 6}O phase forms a three-dimensional covalent network mainly composed of pentagonal pyramids and zig-zag O–B1–O chains extended along c-direction. β-B{sub 6}O phase is found to be stable examined by the calculated elastic constants and phonon dispersion and exhibits metallic behavior and greater elastic and hardness anisotropy, totally different from the semiconducting character and relative isotropy of ground state structure. Moreover, β-B{sub 6}O is predicted to soften significantly with a Vicker’s hardness of about 20.7 GPa.

  5. First-principles study of the elastic and thermodynamic properties of thorium hydrides at high pressure (United States)

    Xiao-Lin, Zhang; Yuan-Yuan, Wu; Xiao-Hong, Shao; Yong, Lu; Ping, Zhang


    The high pressure behaviors of Th4H15 and ThH2 are investigated by using the first-principles calculations based on the density functional theory (DFT). From the energy-volume relations, the bct phase of ThH2 is more stable than the fcc phase at ambient conditions. At high pressure, the bct ThH2 and bcc Th4H15 phases are more brittle than they are at ambient pressure from the calculated elastic constants and the Poisson ratio. The thermodynamic stability of the bct phase ThH2 is determined from the calculated phonon dispersion. In the pressure domain of interest, the phonon dispersions of bcc Th4H15 and bct ThH2 are positive, indicating the dynamical stability of these two phases, while the fcc ThH2 is unstable. The thermodynamic properties including the lattice vibration energy, entropy, and specific heat are predicted for these stable phases. The vibrational free energy decreases with the increase of the temperature, and the entropy and the heat capacity are proportional to the temperature and inversely proportional to the pressure. As the pressure increases, the resistance to the external pressure is strengthened for Th4H15 and ThH2. Project supported by the Long-Term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China.

  6. High-pressure structural and elastic properties of Tl₂O₃

    Energy Technology Data Exchange (ETDEWEB)

    Gomis, O., E-mail:; Vilaplana, R. [Centro de Tecnologías Físicas, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Santamaría-Pérez, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, 46100 Burjassot (Spain); Earth Sciences Department, University College London, Gower Street, WC1E 6BT London (United Kingdom); Ruiz-Fuertes, J. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, 46100 Burjassot (Spain); Geowissenschaften, Goethe-Universität, Altenhöferallee 1, 60438 Frankfurt am Main (Germany); Sans, J. A.; Manjón, F. J.; Mollar, M. [Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); and others


    The structural properties of Thallium (III) oxide (Tl₂O₃) have been studied both experimentally and theoretically under compression at room temperature. X-ray powder diffraction measurements up to 37.7 GPa have been complemented with ab initio total-energy calculations. The equation of state of Tl₂O₃ has been determined and compared to related compounds. It has been found experimentally that Tl₂O₃ remains in its initial cubic bixbyite-type structure up to 22.0 GPa. At this pressure, the onset of amorphization is observed, being the sample fully amorphous at 25.2 GPa. The sample retains the amorphous state after pressure release. To understand the pressure-induced amorphization process, we have studied theoretically the possible high-pressure phases of Tl₂O₃. Although a phase transition is theoretically predicted at 5.8 GPa to the orthorhombic Rh₂O₂-II-type structure and at 24.2 GPa to the orthorhombic α-Gd₂S₃-type structure, neither of these phases were observed experimentally, probably due to the hindrance of the pressure-driven phase transitions at room temperature. The theoretical study of the elastic behavior of the cubic bixbyite-type structure at high-pressure shows that amorphization above 22 GPa at room temperature might be caused by the mechanical instability of the cubic bixbyite-type structure which is theoretically predicted above 23.5 GPa.

  7. Elastic Properties of Tricalcium Aluminate from High-Pressure Experiments and First-Principles Calculations

    KAUST Repository

    Moon, Juhyuk


    The structure and elasticity of tricalcium aluminate (C 3A) have been experimentally and theoretically studied. From high-pressure X-ray diffraction experiments, the bulk modulus of 102(6) and 110(3) GPa were obtained by fitting second- and third-order finite strain equation of state, respectively. First-principles calculations with a generalized gradient approximation gave an isotropic bulk modulus of 102.1 GPa and an isothermal bulk modulus of 106.0 GPa. The static calculations using the exchange-correlation functional show an excellent agreement with the experimental measurements. Based on the agreement, accurate elastic constants and other elastic moduli were computed. The slight difference of behavior at high pressure can be explained by the infiltration of pressure-transmitting silicone oil into structural holes in C 3A. The computed elastic and mechanical properties will be useful in understanding structural and mechanical properties of cementitious materials, particularly with the increasing interest in the advanced applications at the nanoscale. © 2012 The American Ceramic Society.

  8. Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Hoyt, David W.; Sears, Jesse A.; Turcu, Romulus V. F.; Rosso, Kevin M.; Hu, Jian Zhi


    A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

  9. 21 CFR 862.2260 - High pressure liquid chromatography system for clinical use. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

  10. Recent Developments in High-Pressure Research at GSECARS (Invited) (United States)

    Rivers, M. L.; Prakapenka, V.; Wang, Y.; Dera, P. K.; Eng, P.; Newville, M.; Sutton, S. R.


    GeoSoilEnviroCARS (GSECARS) is a national user facility for geoscience research at sector 13 of the Advanced Photon Source, Argonne National Laboratory. GSECARS provides the scientific community with access to high-brightness x-rays and supports a wide range of experimental techniques. Approximately 50% of the research conducted at GSECARS involves high-pressure, both in the diamond anvil cell, and in 250-ton and 1000-ton multi-anvil presses. The other 50% of the research includes x-ray microprobe, microtomography, surface scattering and spectroscopy. The high-pressure experimental techniques provided at the facility include: - Diamond Anvil Cell: Monochromatic diffraction and spectroscopy. Online laser heating is available on the undulator beamline, and external heating is available on the bending magnet beamline. The online laser heating includes two 100W 1060nm fiber lasers and a 200W CO2 laser. - Multi-anvil Press: energy-dispersive and monochromatic diffraction and imaging. There is a 250 ton press on the bending magnet beamline, and a 1000 ton press on the undulator beamline; deformation experiments, acoustic velocity measurements, and computed tomography can all be performed in the press. An addition coming soon is the D-DIA30 module, which is a large multi-stage module for deformation experiments in the 1000-ton press. This device should also permit multi-anvil experiments to approach the megabar pressure range. - Inelastic scattering (X-ray Raman) in the diamond anvil cell. This is performed on a large 6-circle diffractometer in the 13-ID-C station. It is used to determine the electronic structure of low-Z elements, such as B, C, N, and O at high pressure. - Brillouin spectroscopy in the diamond anvil cell. This facility is located on the bending magnet beamline, and allows simultaneous measurement of density (by x-ray diffraction of the sample), pressure (by x-ray diffraction of standard materials), and sound speeds (by Brillouin spectroscopy). Offline

  11. High Pressure Reduction of Selenite by Shewanella oneidensis MR-1 (United States)

    Picard, A.; Daniel, I.; Testemale, D.; Letard, I.; Bleuet, P.; Cardon, H.; Oger, P.


    High-pressure biotopes comprise cold deep-sea environments, hydrothermal vents, and deep subsurface or deep-sea sediments. The latter are less studied, due to the technical difficulties to sample at great depths without contamination. Nevertheless, microbial sulfate reduction and methanogenesis have been found to be spatially distributed in deep deep-sea sediments (1), and sulfate reduction has been shown to be actually more efficient under high hydrostatic pressure (HHP) in some sediments (2). Sulfate-reducing bacteria obtained from the Japan Sea are characterized by an increased sulfide production under pressure (3,4). Unfortunately, investigations of microbial metabolic activity as a function of pressure are extremely scarce due to the experimental difficulty of such measurements at high hydrostatic pressure. We were able to measure the reduction of selenite Se(IV) by Shewanella oneidensis MR-1 as a function of pressure, to 150 MPa using two different high-pressure reactors that allow in situ X-ray spectroscopy measurements on a synchrotron source. A first series of measurements was carried out in a low-pressure Diamond Anvil Cell (DAC) of our own design (5) at ID22 beamline at ESRF (European Synchrotron Radiation Facility); a second one was performed in an autoclave (6) at the BM30B beamline at ESRF. Selenite reduction by strain MR-17 was monitored from ambient pressure to 150 MPa over 25 hours at 30 deg C by XANES spectroscopy (X-ray Analysis of Near Edge Structure). Spectra were recorded hourly in order to quantify the evolution of the oxidation state of selenium with time. Stationary-phase bacteria were inoculated at a high concentration into fresh growth medium containing 5 or 10 M of sodium selenite and 20 mM sodium lactate. Kinetic parameters of the Se (IV) reduction by Shewanella oneidensis strain MR-1 could be extracted from the data, as a function of pressure. They show 1) that the rate constant k of the reaction is decreased by a half at high pressure

  12. Anomalous high pressure behaviour in nanosized rare earth sesquioxides

    Energy Technology Data Exchange (ETDEWEB)

    Dilawar, Nita; Varandani, Deepak; Mehrotra, Shalini; Bandyopadhyay, Ashis K [Pressure and Vacuum Standards, National Physical Laboratory, Dr K S Krishnan Road, New Delhi 110012 (India); Poswal, Himanshu K; Sharma, Surinder M [High Pressure Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)


    We report Raman spectroscopic studies of the nanosized rare earth sesquioxides, namely yttrium sesquioxide (Y{sub 2}O{sub 3}), gadolinium sesquioxide (Gd{sub 2}O{sub 3}) and samarium sesquioxide (Sm{sub 2}O{sub 3}), under high pressure. The samples were characterized using x-ray diffraction, Raman spectroscopy and atomic force microscopy at atmospheric pressures. Y{sub 2}O{sub 3} and Gd{sub 2}O{sub 3} were found to be cubic at ambient, while Sm{sub 2}O{sub 3} was found to be predominantly cubic with a small fraction of monoclinic phase. The strongest Raman peaks are observed at 379, 344 and 363 cm{sup -1}, respectively, for Y{sub 2}O{sub 3}, Sm{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. All the samples were found to be nanosized with 50-90 nm particle sizes. The high pressures were generated using a Mao-Bell type diamond anvil cell and a conventional laser Raman spectrometer is used to monitor the pressure-induced changes. Y{sub 2}O{sub 3} seems to undergo a crystalline to partial amorphous transition when pressurized up to about 19 GPa, with traces of hexagonal phase. However, on release of pressure, the hexagonal phase develops into the dominant phase. Gd{sub 2}O{sub 3} is also seen to develop into a mixture of amorphous and hexagonal phases on pressurizing. However, on release of pressure Gd{sub 2}O{sub 3} does not show any change and the transformation is found to be irreversible. On the other hand, Sm{sub 2}O{sub 3} shows a weakening of cubic phase peaks while monoclinic phase peaks gain intensity up to about a pressure of 6.79 GPa. However, thereafter the monoclinic phase peaks also reduce in intensity and mostly disordering sets in which does not show significant reversal as the pressure is released. The results obtained are discussed in detail.

  13. Viscosity in hot mix construction. (United States)


    Viscosity, one of the oldest known and tested properties of Asphalt, yet one of the least studied is recently being given the attention it so rightfully deserves. Numerous engineers did recognize the importance of this property to the extent that sev...

  14. Effective viscosity of confined hydrocarbons

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, V.N.; Persson, B.N.J.


    We present molecular dynamics friction calculations for confined hydrocarbon films with molecular lengths from 20 to 1400 carbon atoms. We find that the logarithm of the effective viscosity ηeff for nanometer-thin films depends linearly on the logarithm of the shear rate: log ηeff=C-nlog γ̇, where...

  15. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)


    Jul 29, 2015 ... We discuss the role of nuclear viscosity in hindering the fission of heavy nuclei as observed in the experimental measurements of GDR -ray spectra from the fissioning nuclei. We review a set of experiments carried out and reported by us previously [see Dioszegi et al, Phys. Rev. C 61, 024613 (2000); ...

  16. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)

    is in exact conformity with all the previous measurements [7,10–13]. The CASCADE calculations (solid lines in figure 1) used in this first level of analysis do not include any viscosity or temperature-dependent nuclear level density parameter a. The γ and particle decay are calculated using the standard prescriptions as ...

  17. Intrinsic viscosity of guar gum in sweeteners solutions | Samavati ...

    African Journals Online (AJOL)

    Rheological methods were applied to study the effect of sweeteners on the rheological behavior of guar gum in dilute solutions. The concentration of the sweeteners were 0.1, 0.2%w/v for aspartame, acesulfame-k and cyclamate, and 0.001, 0.002%w/v for neotame. Gum was evaluated for intrinsic viscosity by various ...

  18. Steady shear viscosity of stirred yoghurts with varying ropiness

    NARCIS (Netherlands)

    van Marle, M.E.; van Marle, M.E.; van den Ende, Henricus T.M.; de Kruif, C.G.; de Kruif, C.G.; Mellema, J.


    Stirred yogurt was viewed as a concentrated dispersion of aggregates consisting of protein particles. The steady-shear behavior of three types of stirred yogurt with varying ropiness was investigated experimentally. To describe the shear-dependent viscosity, a microrheological model was used which

  19. High-pressure Moessbauer study of perovskite iron oxides

    CERN Document Server

    Kawakami, T; Sasaki, T; Kuzushita, K; Morimoto, S; Endo, S; Kawasaki, S; Takano, M


    The perovskite oxides CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 have been investigated by high-pressure sup 5 sup 7 Fe Moessbauer spectroscopy. The critical temperatures of the charge disproportionation (CD) and the magnetic order (MO) have been determined as a function of pressure. In CaFeO sub 3 the CD (2Fe sup 4 sup + -> Fe sup 3 sup + + Fe sup 5 sup +) occurs at an almost constant temperature of 290 K in the pressure range of 0-17 GPa. Above 20 GPa, the CD is suppressed. The MO temperature of 125 K at an ambient pressure rises to 300 K at 34 GPa. In La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 the CD (3Fe sup 1 sup 1 sup / sup 3 sup + -> 2Fe sup 3 sup + + Fe sup 5 sup +) and the MO occur at the same temperature up to 21 GPa, which decreases from 207 to 165 K with increasing pressure. Above 25 GPa, however, the MO temperature rises above 400 K.

  20. Production of nanograined intermetallics using high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Alhamidi, Ali; Edalati, Kaveh; Horita, Zenji, E-mail: [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka (Japan)


    Formation of intermetallics is generally feasible at high temperatures when the lattice diffusion is fast enough to form the ordered phases. This study shows that nanograined intermetallics are formed at a low temperature as 573 K in Al- 25 mol% Ni, Al- 50 mol.% Ni and Al- 50 mol% Ti powder mixtures through powder consolidation using high-pressure torsion (HPT). For the three compositions, the hardness gradually increases with straining but saturates to the levels as high as 550-920 Hv. In addition to the high hardness, the TiAl material exhibits high yield strength as {approx}3 GPa with good ductility as {approx}23%, when they are examined by micropillar compression tests. X-ray diffraction analysis and high-resolution transmission electron microscopy reveal that the significant increase in hardness and strength is due to the formation of nanograined intermetallics such as Al{sub 3}Ni, Al{sub 3}Ni{sub 2}, TiAl{sub 3}, TiAl{sub 2} and TiAl with average grain sizes of 20-40 nm (author)

  1. Effect of high pressure on cod (Gadus morhua) desalting (United States)

    Salvador, Ângelo C.; Saraiva, Jorge A.; Fidalgo, Liliana G.; Delgadillo, Ivonne


    The effect of high pressure on salt and water diffusion in the desalting process of cod was studied. Under pressure, up to 300 MPa, the osmotic equilibrium is reached much faster, compared to desalting at atmospheric pressure. Water (D ew) and salt (D es) effective diffusion coefficients reached a maximum at 200 MPa, increasing 500- and 160-fold, respectively, compared with desalting at atmospheric pressure. Increasing pressure up to 300 MPa causes a reduction in both effective diffusion coefficients, although they were still about 70-fold higher than at atmospheric pressure. Up to 200 MPa, a linear correlation was found between D ew and D es and pressure. However, the total diffused amounts of water and salt, when the osmotic equilibrium was reached, were lower under pressure. At atmospheric pressure cod water content increased 1.65-fold, but under pressure the increment was on average 1.25-fold, while salt content decreased to 0.51-fold the initial value at atmospheric pressure and to around 0.75-fold under pressure.

  2. Efficiency of liquid-jet high-pressure booster compressors (United States)

    Mikheev, N. I.; Davletshin, I. A.; Mikheev, A. N.; Kratirov, D. V.; Fafurin, V. A.


    There are almost no experimental data on the head-capacity curves for liquid-jet compressors with the inlet gas pressure of liquid-jet apparatus more than 1 MPa. Meanwhile, this range is important for many engineering applications in which relatively low compressor ratio is required for the pumping of gas under high pressure. This is mostly the case when gas circulation is to be provided in a closed or almost closed circuit. A head-capacity curve of a liquid-jet apparatus has been estimated experimentally for the air pumping at up to 2.5 MPa by a water jet. To obtain this curve, a new original technique has been submitted and verified which is based on an inverse unsteady problem of gas pumping and allows derivation of the whole curve instead of one operating point, which is the case for conventional methods. The experiments have demonstrated that the relative head of the liquid-jet compressor grows with the apparatus inlet air pressure in the middle part of the curve.

  3. X-ray Diffraction Study of Arsenopyrite at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    D Fan; M Ma; W Zhou; S Wei; Z Chen; H Xie


    The high-pressure X-ray diffraction study of a natural arsenopyrite was investigated up to 28.2 GPa using in situ angle-dispersive X-ray diffraction and a diamond anvil cell at National Synchrotron Light Source, Brookhaven National Laboratory. The 16:3:1 methanol-ethanol-water mixture was used as a pressure-transmitting medium. Pressures were measured using the ruby-fluorescence method. No phase change has been observed up to 28.2 GPa. The isothermal equation of state (EOS) was determined. The values of K{sub 0}, and K'{sub 0} refined with a third-order Birch-Murnaghan EOS are K{sub 0} = 123(9) GPa, and K'{sub 0} = 5.2(8). Furthermore, we confirm that the linear compressibilities ({beta}) along a, b and c directions of arsenopyrite is elastically isotropic ({beta}{sub a} = 6.82 x 10{sup -4}, {beta}{sub b} = 6.17 x 10{sup -4} and {beta}{sub c} = 6.57 x 10{sup -4} GPa{sup -1}).

  4. High-pressure studies of cycloheptane up to 30 GPa (United States)

    Ma, Chunli; Cui, Qiliang; Liu, Zhenxian


    High-pressure synchrotron angle dispersive x-ray diffraction, Raman scattering and infrared absorption studies have been performed on cycloheptane (C7H14) up to 30 GPa at room temperature by using diamond anvil cell techniques. The synchrotron x-ray diffraction results indicate that the liquid cyclopentane undergoes two phase transitions at around 0.5 and 1.0 GPa, respectively. Then, it gradually turns into glass state starting from 3.0 GPa. The features of the Raman scattering and infrared absorption show no significant changes with increasing pressure below 3 GPa. This implies that the two phases observed by the x-ray diffraction can be attributed to plastic phases in which the cycloheptane molecules are held in an ordered structure while the molecular orientation is disordered. Up on further compression, all Raman and infrared bands begin broadening around 3.0 GPa that provide further evidence on the transition to glass state. Our results also suggest different paths on phase transitions under isothermal compression at room temperature compare to that previously reported under isobaric cooling at ambient pressure. This work was supported by the NSF of China (91014004, 11004074,11074089), the specialized Research Fund for the Doctoral Program of Higher Education (20110061110011, 20100061120093), and the National Basic Research Program of China (2011CB808200).

  5. High pressure die casting of Fe-based metallic glass. (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András


    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  6. High pressure die casting of Fe-based metallic glass (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András


    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  7. Reducing peanut allergens by high pressure combined with polyphenol oxidase (United States)

    Chung, Si-Yin; Houska, Milan; Reed, Shawndrika


    Polyphenol oxidase (PPO) has been shown to reduce major peanut allergens. Since high pressure (HP) can increase enzyme activity, we postulated that further reduction of peanut allergens can be achieved through HP combined with PPO. Peanut extracts containing caffeic acid were treated with each of the following: (1) HP; (2) HP+PPO; (3) PPO; and (4) none. HP was conducted at 300 and 500 MPa, each for 3 and 10 min, 37 °C. After treatment, SDS-PAGE was performed and allergenic capacity (IgE binding) was determined colorimetrically in inhibition enzyme-linked immunosorbent assay and Western blots, using a pooled plasma from peanut-allergic patients. Data showed that HP alone had no effect on major peanut allergens. However, HP at 500 MPa combined with PPO (HP500/PPO) induced a higher (approximately twofold) reduction of major peanut allergens and IgE binding than PPO alone or HP300/PPO. There was no difference between treatment times. We concluded that HP500/PPO at 3-min enhanced a twofold reduction of the allergenic capacity of peanut extracts, as compared to PPO itself.

  8. Energy Efficient High-Pressure Turbine Leakage Technology Report (United States)

    Gardner, W. B.


    The leakage test program was one of such supporting technology programs structured to provide guidance to the Energy Efficient Engine High Pressure Turbine Component Design Effort. Leakage reduction techniques were identified and evaluated. Test models were used to simulate component leak paths and to evaluate leakage reduction techniques. These models simulated the blade/disk attachment, the vane inner platform attachment, and the vane outer platform attachment combined with the blade outer airseal. Disk blade attachment testing indicated that leakage in this area could be reduced to very low levels by paying careful attention to the tolerances along the contact surface between the blade vibration damper and the blade platform contact surface. The aim of feather seal testing was to achieve a goal for an effective leakage gap of one mil (.001 inch) per inch of feather seal length. Results indicated that effective gaps even below the goal level were achievable by (1) maintaining close tolerances between feather seals and their slots to minimize end gaps and limit seal rotation, (2) avoiding feather seal overlap, and (3) minimizing feather seal intersections. W seals were shown to be effective leakage control devices. Wire rope, in its present state of development, was shown not to be an effective sealing concept for application to the component design.

  9. Integrated high pressure microhydraulic actuation and control for surgical instruments. (United States)

    Moers, A J M; De Volder, M F L; Reynaerts, D


    To reduce the surgical trauma to the patient, minimally invasive surgery is gaining considerable importance since the eighties. More recently, robot assisted minimally invasive surgery was introduced to enhance the surgeon's performance in these procedures. This resulted in an intensive research on the design, fabrication and control of surgical robots over the last decades. A new development in the field of surgical tool manipulators is presented in this article: a flexible manipulator with distributed degrees of freedom powered by microhydraulic actuators. The tool consists of successive flexible segments, each with two bending degrees of freedom. To actuate these compliant segments, dedicated fluidic actuators are incorporated, together with compact hydraulic valves which control the actuator motion. Especially the development of microvalves for this application was challenging, and are the main focus of this paper. The valves distribute the hydraulic power from one common high pressure supply to a series of artificial muscle actuators. Tests show that the angular stroke of the each segment of this medical instrument is 90°.

  10. Microbial growth under a high-pressure CO2 environment (United States)

    Thompson, J. R.; Hernandez, H. H.


    Carbon capture and storage (CCS) of CO2 has the potential to significantly reduce the emission of greenhouse gasses associated with fossil fuel combustion. The largest potential for storing captured CO2 in the United Sates is in deep geologic saline formations. Currently, little is known about the effects of CO2 storage on biologically active microbial communities found in the deep earth biosphere. Therefore, to investigate how deep earth microbial communities will be affected by the storage of CO2, we have built a high-pressure microbial growth system in which microbial samples are subjected to a supercritical CO2 (scCO2) environment. Recently we have isolated a microbial consortium that is capable of growth and extracellular matrix production in nutrient media under a supercritical CO2 headspace. This consortium was cultivated from hydrocarbon residues associated with saline formation waters and includes members of the gram-positive Bacillus genus. The cultivation of actively growing cells in an environment containing scCO2 is unexpected based on previous experimental evidence of microbial sterilization attributed to the acidic, desiccating, and solvent-like properties of scCO2. Such microbial consortia have potential for development as (i) biofilm barriers for geological carbon-dioxide sequestration, and as (ii) agents of biocatalysis in environmentally-friendly supercritical (sc) CO2 solvent systems. The discovery that microbes can remain biologically active, and grow, in these environments opens new frontiers for the use of self-regenerating biological systems in engineering applications.

  11. Pulsed laser kinetic studies of liquids under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Eyring, E.M.


    Experiments have been developed for measuring the rates of chemical reactions liquids and in supercritical Co[sub 2]. A pulsed (Q-switch) Nd:YAG laser at 355 nm was the pump beam for laser flash photolysis studies of molybdenum and tungsten hexacarbonyls undergoing ligand displacement reactions by bidentate chelating agents such as 2,2[prime]-bipyridine in toluene. Experiments were carried out at 0.1 to 150 MPa. In the case of molybdenum complexes, the reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2[prime]-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Similar high pressure flash photolysis experiments with tungsten hexacarbonyl have also been completed. The concentration dependence of the fluorescence and nonradiative decay quantum yields for cresyl violet in several solvent have been reported as well as stability constants for the complexation of lithium ion by four different crown ethers dissolved in a room temperature molten salt.

  12. Bio-mass utilization in high pressure cogeneration boiler (United States)

    Koundinya, Sandeep; Maria Ambrose Raj, Y.; Sreeram, K.; Divakar Shetty A., S.


    Coal is widely used all over the world in almost all power plants. The dependence on coal has increased enormously as the demand for electricity has reached its peak. Coal being a non-renewable source is depleting fast. We being the engineers, it's our duty to conserve the natural resources and optimize the coal consumption. In this project, we have tried to optimize the bio-mass utilization in high pressure cogeneration boiler. The project was carried in Seshasayee Paper and Boards Limited, erode related to Boiler No:10 operating at steam pressure of 105 kscg and temperature of 510°C. Available bio-mass fuels in and around the mill premises are bagasse, bagasse pith, cane trash and chipper dust. In this project, we have found out the coal equivalent replacement by the above bio-mass fuel(s) to facilitate deciding on the optimized quantity of coal that can be replaced by biomass without modifying the existing design of the plant. The dominant fuel (coal) which could be displaced with the substitute biomass fuel had been individually (biomass) analyzed.

  13. Dense superconducting phases of copper-bismuth at high pressure (United States)

    Amsler, Maximilian; Wolverton, Chris


    Although copper and bismuth do not form any compounds at ambient conditions, two intermetallics, CuBi and Cu11Bi7 , were recently synthesized at high pressures. Here we report on the discovery of additional copper-bismuth phases at elevated pressures with high densities from ab initio calculations. In particular, a Cu2Bi compound is found to be thermodynamically stable at pressures above 59 GPa, crystallizing in the cubic Laves structure. In strong contrast to Cu11Bi7 and CuBi, cubic Cu2Bi does not exhibit any voids or channels. Since the bismuth lone pairs in cubic Cu2Bi are stereochemically inactive, the constituent elements can be closely packed and a high density of 10.52 g/cm3 at 0 GPa is achieved. The moderate electron-phonon coupling of λ =0.68 leads to a superconducting temperature of 2 K, which exceeds the values observed both in Cu11Bi7 and CuBi, as well as in elemental Cu and Bi.

  14. High pressure oxidation of C2H4/NO mixtures

    DEFF Research Database (Denmark)

    Giménez-López, J.; Alzueta, M.U.; Rasmussen, C.T.


    An experimental and kinetic modeling study of the interaction between C2H4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600–900K), high pressure (60bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction...... pathways of the C2H4/O2/NOx conversion, the capacity of C2H4 to remove NO, and the influence of the presence of NOx on the C2H4 oxidation are analyzed. Compared to the C2H4/O2 system, the presence of NOx shifts the onset of reaction 75–150K to lower temperatures. The mechanism of sensitization involves...... is removed. This removal is partly explained by the reaction C2H3+NO→HCN+CH2O. However, a second removal mechanism is active in the 700–850K range, which is not captured by the chemical kinetic model. With the present thermochemistry and kinetics, neither formation of nitro-hydrocarbons (CH3NO2, C2H3NO2, C2H...

  15. New perspectives on potential hydrogen storage materials using high pressure. (United States)

    Song, Yang


    In addressing the global demand for clean and renewable energy, hydrogen stands out as the most suitable candidate for many fuel applications that require practical and efficient storage of hydrogen. Supplementary to the traditional hydrogen storage methods and materials, the high-pressure technique has emerged as a novel and unique approach to developing new potential hydrogen storage materials. Static compression of materials may result in significant changes in the structures, properties and performance that are important for hydrogen storage applications, and often lead to the formation of unprecedented phases or complexes that have profound implications for hydrogen storage. In this perspective article, 22 types of representative potential hydrogen storage materials that belong to four major classes--simple hydride, complex hydride, chemical hydride and hydrogen containing materials--were reviewed. In particular, their structures, stabilities, and pressure-induced transformations, which were reported in recent experimental works together with supporting theoretical studies, were provided. The important contextual aspects pertinent to hydrogen storage associated with novel structures and transitions were discussed. Finally, the summary of the recent advances reviewed and the insight into the future research in this direction were given.


    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi


    The Vapor Liquid Equilibrium measurement setup of this work was first established several years ago. It is a flow type high temperature high pressure apparatus which was designed to operate below 500 C temperature and 2000 psia pressure. Compared with the static method, this method has three major advantages: the first is that large quantity of sample can be obtained from the system without disturbing the equilibrium state which was established before; the second is that the residence time of the sample in the equilibrium cell is greatly reduced, thus decomposition or contamination of the sample can be effectively prevented; the third is that the flow system allows the sample to degas as it heats up since any non condensable gas will exit in the vapor stream, accumulate in the vapor condenser, and not be recirculated. The first few runs were made with Quinoline-Tetralin system, the results were fairly in agreement with the literature data . The former graduate student Amad used the same apparatus acquired the Benzene-Ethylbenzene system VLE data. This work used basically the same setup (several modifications had been made) to get the VLE data of Ethylbenzene-Quinoline system.

  17. The Eoalpine High Pressure Belt west of the Tauern Window (United States)

    Pomella, Hannah; Flöss, David; Speckbacher, Romed; Tropper, Peter; Fügenschuh, Bernhard


    Eclogites in the Texel Unit (Eastern Alps; South Tyrol, Italy) represent the westernmost outcrops of the E-W striking Eoalpine High Pressure Belt (EHB), a key feature of the Eastern Alps. The EHB forms part of a Cretaceous intra-continental, south(east) dipping subduction/collision zone as visible east of the Tauern window. West of the Tauern window the same nappe stack displays a northwest dip giving rise for discussion on the general setting. Based on own observations and literature data we present a new and coherent tectonic model for the eastern end of the EHB: Despite at present the major structures dip to northwest the subduction was originally directed to south(east). Due to the special situation of this area at the tip of the Southalpine indenter the originally south(east) dipping structures became overturned and former thrusts appear as normal faults (e.g. Schneeberg fault zone) while former normal faults presently display thrust geometries (e.g. Jaufen fault). Two crustal-scale cross-sections together with an evolution model are presented to illustrate the model.

  18. Pulse Radiolysis at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Christensen, H.; Sehested, Knud


    A set-up enabling pulse radiolysis measurements at high temperatures (up to 320°C) and high pressures (up to 140 bar) has been constructed in collaboration between Risö National Laboratory and Studsvik Energiteknik. The cell has been used for experiments with aqueous solutions with the purpose.......2 kcal.mol−1) and OH+OH (tentatively 8 kJ·mol−1, 1.9 kcal·mol−1) have been determined. The absorption spectrum of the OH radical has been determined up to temperatures of 200°C. The absorption maximum is found at 230 nm at all temperatures. The reaction between Fe2+ and OH radicals has been studied up...... to a temperature of 220°C. An activation energy of 9 kJ·mol−1 (2.2 kcal·mol−1) has been determined and the spectrum of the transient formed in the reaction has been determined at different temperatures....

  19. Future directions in high-pressure neutron diffraction (United States)

    Guthrie, M.


    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy.

  20. High pressure inactivation of Brettanomyces bruxellensis in red wine. (United States)

    van Wyk, Sanelle; Silva, Filipa V M


    Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Optimization of stent implantation using a high pressure inflation protocol. (United States)

    Vallurupalli, Srikanth; Bahia, Amit; Ruiz-Rodriguez, Ernesto; Ahmed, Zubair; Hakeem, Abdul; Uretsky, Barry F


    High-pressure inflation is the universal standard for stent deployment but a specific protocol for its use is lacking. We developed a standardized "pressure optimization protocol" (POP) using time to inflation pressure stability as an endpoint for determining the required duration of stent inflation. The primary study purpose was to determine the stent inflation time (IT) in a large patient cohort using the standardized inflation protocol, to correlate various patient and lesion characteristics with IT, and ascertain in an in vitro study the time for pressure accommodation within an inflation system. Six hundred fifteen stent implants in 435 patients were studied. Multivariate analysis was performed to determine predictors of longer ITs. In an in vitro study, various stents and balloons were inflated in air to determine the pressure accommodation time of the inflation system. The mean stent IT was 104 ± 41 sec (range 30-380 sec). Stent length was the only predictor of prolonged stent inflation. The "accommodation time" in vitro of the stent inflation system itself was 33 ± 24 sec. The protocol was safe requiring premature inflation termination in expand the stent and that the use of a pressure stability protocol will allow for safe, predictable, and more complete stent deployment. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  2. The viscosity of Earth's lower mantle inferred from sinking speed of subducted lithosphere

    NARCIS (Netherlands)

    Čížková, H.; van den Berg, A.P.; Spakman, W.; Matyska, C.


    The viscosity of the mantle is indispensable for predicting Earth's mechanical behavior at scales ranging from deep mantle material flow to local stress accumulation in earthquakes zones. But, mantle viscosity is not well determined. For the lower mantle, particularly, only few constraints result

  3. Net Shape Manufacturing of Accelerator Components by High Pressure Combustion Driven Powder Compaction

    CERN Document Server

    Nagarathnam, Karthik


    We present an overview of the net shape and cost-effective manufacturing aspects of high density accelerator (normal and superconducting) components (e.g., NLC Copper disks) and materials behavior of copper, stainless steel, refractory materials (W, Mo and TZM), niobium and SiC by innovative high pressure Combustion Driven Compaction (CDC) technology. Some of the unique process advantages include high densities, net-shaping, improved surface finish/quality, suitability for simple/complex geometries, synthesis of single as well as multilayered materials, milliseconds of compaction process time, little or no post-machining, and process flexibility. Some of the key results of CDC fabricated sample geometries, process optimization, sintering responses and structure/property characteristics such as physical properties, surface roughness/quality, electrical conductivity, select microstructures and mechanical properties will be presented. Anticipated applications of CDC compaction include advanced x-ray targets, vac...

  4. Work-hardening induced tensile ductility of bulk metallic glasses via high-pressure torsion. (United States)

    Joo, Soo-Hyun; Pi, Dong-Hai; Setyawan, Albertus Deny Heri; Kato, Hidemi; Janecek, Milos; Kim, Yong Chan; Lee, Sunghak; Kim, Hyoung Seop


    The mechanical properties of engineering materials are key for ensuring safety and reliability. However, the plastic deformation of BMGs is confined to narrow regions in shear bands, which usually result in limited ductilities and catastrophic failures at low homologous temperatures. The quasi-brittle failure and lack of tensile ductility undercut the potential applications of BMGs. In this report, we present clear tensile ductility in a Zr-based BMG via a high-pressure torsion (HPT) process. Enhanced tensile ductility and work-hardening behavior after the HPT process were investigated, focusing on the microstructure, particularly the changed free volume, which affects deformation mechanisms (i.e., initiation, propagation, and obstruction of shear bands). Our results provide insights into the basic functions of hydrostatic pressure and shear strain in the microstructure and mechanical properties of HPT-processed BMGs.

  5. High pressure supercritical water - still an open field

    Energy Technology Data Exchange (ETDEWEB)

    Franck, E.U. [Inst. fuer Physikalische Chemie, Univ. Karlsruhe (Germany)


    A selected group of thermophysical phenomena of aqueous systems is presented and discussed. Emphasis is given to temperatures well above the critical temperature of water and to pressures extending in some cases to 3000 bar. Special attention is given to homogeneous supercritical binary mixture systems. The viscosity of water to 1000 C is discussed as well as the thermal conductivity and the static dielectric constant. As an example for dense water-molten salt systems, measurements of density and electrolytic conductivity up to the pure molten sodium hydroxide are shown. - Above its critical temperature the dense water is miscible also with nonpolar partners. Sveral of these have practical interest, for example H{sub 2}O-CO{sub 2}, H{sub 2}O-CH{sub 4}, H{sub 2}O-H{sub 2} and H{sub 2}O-O{sub 2}. Critical curves are demonstrated and discussed with phase diagrams of ternary systems to 2500 bar. ''Hydrothermal'' diffusion flames in dense H{sub 2}O-CH{sub 4} mixtures to 1000 bar can be produced and are presented. For the first time a phase diagram of the ternary water-oxyhydrogen system is shown, calculated to 350 C and 2500 bar. Also for hydrogen fluoride the molar volume V = (p,T) is shown for the first time to 2000 bar and 600 C. (orig.)

  6. Compressible Reynolds equation for high-pressure gases (United States)

    Chien, S. Y.; Cramer, M. S.; Untaroiu, A.


    We derive the Reynolds equation corresponding to steady, laminar, two-dimensional, compressible flows of single-phase Navier-Stokes fluids in a thin gap between a stationary surface and one translating with constant speed. The thermodynamic state of the fluid is taken to be in the dense and supercritical gas regimes. The equation of state is a well-known cubic equation, and the shear viscosity and thermal conductivity are taken to depend on density and temperature. Thermal boundary conditions are taken to include those for constant-temperature and adiabatic walls. The flow is seen to be governed by both the speed number and a single thermodynamic parameter referred to as the effective bulk modulus. Numerical solutions to the Reynolds equation are compared to those of the full Navier-Stokes equations. It is shown that the Reynolds equation breaks down in the vicinity of the thermodynamic critical point. Furthermore, we show that energy convection is negligible whenever the Reynolds equation is valid which enables us to present new explicit solutions for the temperature distributions.

  7. Optical properties of V1-xCrxO2 compounds under high pressure (United States)

    Marini, C.; Arcangeletti, E.; di Castro, D.; Baldassare, L.; Perucchi, A.; Lupi, S.; Malavasi, L.; Boeri, L.; Pomjakushina, E.; Conder, K.; Postorino, P.


    Raman and infrared transmission and reflectivity measurements were carried out at room temperature and high pressure (0-15 GPa) on V1-xCrxO2 compounds. Raman spectra were collected at ambient conditions on the x=0.007 and 0.025 materials, which are characterized by different insulating monoclinic phases ( M3 and M2 , respectively), while infrared spectra were collected on the x=0.025 sample only. The present data were compared with companion results on undoped VO2 [E. Arcangeletti , Phys. Rev. Lett. 98, 196406 (2007)], which is found at ambient conditions in a different, third insulating monoclinic phase, named M1 . This comparison allowed us to investigate the effects of different extents of structural distortions (Peierls distortion) on the lattice dynamics and the electronic properties of this family of compounds. The pressure dependence of the Raman spectrum of VO2 and Cr-doped samples shows that all the systems retain the monoclinic structure up to the highest explored pressure, regardless the specific monoclinic structure ( M1 , M2 , and M3 ) at ambient condition. Moreover, the Raman spectra of the two Cr-doped samples, which exhibit an anomalous behavior over the low-pressure range (P<8GPa) , merge into that of VO2 in the high-pressure regime and are all found into a common monoclinic phase (a possible fourth kind phase). Combining Raman and infrared results on both the VO2 and the present data, we found that a common metallic monoclinic phase appears accessible in the high-pressure regime at room temperature for both undoped and Cr-doped samples independently of the different extents of Peierls distortion at ambient conditions. This finding differs from the behavior observed at ambient pressure, where the metallic phase is found only in conjunction with the rutile structure. The whole of these results suggests a major role of the electron correlations, rather than of the Peierls distortion, in driving the metal-insulator transition in vanadium dioxide

  8. Water-bearing, high-pressure Ca-silicates (United States)

    Németh, Péter; Leinenweber, Kurt; Ohfuji, Hiroaki; Groy, Thomas; Domanik, Kenneth J.; Kovács, István J.; Kovács, Judit S.; Buseck, Peter R.


    Water-bearing minerals provide fundamental knowledge regarding the water budget of the mantle and are geophysically significant through their influence on the rheological and seismic properties of Earth's interior. Here we investigate the CaO-SiO2-H2O system at 17 GPa and 1773 K, corresponding to mantle transition-zone condition, report new high-pressure (HP) water-bearing Ca-silicates and reveal the structural complexity of these phases. We document the HP polymorph of hartrurite (Ca3SiO5), post-hartrurite, which is tetragonal with space group P4/ncc, a = 6.820 (5), c = 10.243 (8) Å, V = 476.4 (8) Å3, and Z = 4, and is isostructural with Sr3SiO5. Post-hartrurite occurs in hydrous and anhydrous forms and coexists with larnite (Ca2SiO4), which we find also has a hydrous counterpart. Si is 4-coordinated in both post-hartrurite and larnite. In their hydrous forms, H substitutes for Si (4H for each Si; hydrogrossular substitution). Fourier transform infrared (FTIR) spectroscopy shows broad hydroxyl absorption bands at ∼3550 cm-1 and at 3500-3550 cm-1 for hydrous post-hartrurite and hydrous larnite, respectively. Hydrous post-hartrurite has a defect composition of Ca2.663Si0.826O5H1.370 (5.84 weight % H2O) according to electron-probe microanalysis (EPMA), and the Si deficiency relative to Ca is also observed in the single-crystal data. Hydrous larnite has average composition of Ca1.924Si0.851O4H0.748 (4.06 weight % H2O) according to EPMA, and it is in agreement with the Si occupancy obtained using X-ray data collected on a single crystal. Superlattice reflections occur in electron-diffraction patterns of the hydrous larnite and could indicate crystallographic ordering of the hydroxyl groups and their associated cation defects. Although textural and EPMA-based compositional evidence suggests that hydrous perovskite may occur in high-Ca-containing (or low silica-activity) systems, the FTIR measurement does not show a well-defined hydroxyl absorption band for this

  9. Solubility of silicon in hcp-iron at high pressure (United States)

    Kuwayama, Y.


    The Earth's outer core is believed to be composed of liquid iron alloy with one or more light elements (e.g., Birch 1952; Poirier 1994). Although a number of elements lighter than iron, including hydrogen, carbon, oxygen, silicon, and sulfur, have been considered by various researchers as potential light elements in the Earth's core, silicon is one of the most attractive candidates for the light element in the core (e.g., Takafuji et al. 2005; Sakai et al. 2006; Ozawa et al. 2008, 2009, Wood et al., 2008). The Earth's inner core is considered to consist mainly of a solid iron-nickel alloy. However, multiple experimental studies revealed that the inner core is also less dense than pure iron, indicating the presence of light components in the inner core (e.g., Jephcoat and Olson 1987; Mao et al. 1998; Lin et al. 2005; Badro et al. 2007). If silicon is indeed a major light element in the liquid outer core, the maximum amount of silicon that can be incorporated in the solid inner core during inner-core solidification is limited by the solubility of silicon in solid iron at the pressure of the inner core boundary. Therefore the phase relations of iron-silicon alloys, especially the solubility of silicon in solid iron at high pressure and temperature, are the key to understanding the composition, structure, and crystallization of the inner core. The phase relations of iron-silicon alloys at high pressure have been extensively studied using a multi-anvil apparatus (Zhang and Guyot 1999; Dobson et al. 2002; Kuwayama and Hirose 2004) and a diamond-anvil cell with in-situ x-ray diffraction measurements (Lin et al. 2002; Lin et al. 2003; Dubrovinsky et al. 2003; Hirao et al. 2004; Asanuma et al. 2008, Lin et al 2009, Kuwayama et al. 2009). Below 200 GPa, the solubility of silicon in solid hcp-iron has been well studied. Solid hcp-iron can contain at least ~10 wt% Si at low temperature, but it decomposed to iron-rich hcp phase and silicon-rich bcc phase at high temperature

  10. High pressure humidification columns: Design equations, algorithm, and computer code

    Energy Technology Data Exchange (ETDEWEB)

    Enick, R.M. [Pittsburgh Univ., PA (United States). Dept. of Chemical and Petroleum Engineering; Klara, S.M. [USDOE Pittsburgh Energy Technology Center, PA (United States); Marano, J.J. [Burns and Roe Services Corp., Pittsburgh, PA (United States)


    This report describes the detailed development of a computer model to simulate the humidification of an air stream in contact with a water stream in a countercurrent, packed tower, humidification column. The computer model has been developed as a user model for the Advanced System for Process Engineering (ASPEN) simulator. This was done to utilize the powerful ASPEN flash algorithms as well as to provide ease of use when using ASPEN to model systems containing humidification columns. The model can easily be modified for stand-alone use by incorporating any standard algorithm for performing flash calculations. The model was primarily developed to analyze Humid Air Turbine (HAT) power cycles; however, it can be used for any application that involves a humidifier or saturator. The solution is based on a multiple stage model of a packed column which incorporates mass and energy, balances, mass transfer and heat transfer rate expressions, the Lewis relation and a thermodynamic equilibrium model for the air-water system. The inlet air properties, inlet water properties and a measure of the mass transfer and heat transfer which occur in the column are the only required input parameters to the model. Several example problems are provided to illustrate the algorithm`s ability to generate the temperature of the water, flow rate of the water, temperature of the air, flow rate of the air and humidity of the air as a function of height in the column. The algorithm can be used to model any high-pressure air humidification column operating at pressures up to 50 atm. This discussion includes descriptions of various humidification processes, detailed derivations of the relevant expressions, and methods of incorporating these equations into a computer model for a humidification column.

  11. Microstructural analysis of aluminum high pressure die castings (United States)

    David, Maria Diana

    Microstructural analysis of aluminum high pressure die castings (HPDC) is challenging and time consuming. Automating the stereology method is an efficient way in obtaining quantitative data; however, validating the accuracy of this technique can also pose some challenges. In this research, a semi-automated algorithm to quantify microstructural features in aluminum HPDC was developed. Analysis was done near the casting surface where it exhibited fine microstructure. Optical and Secondary electron (SE) and backscatter electron (BSE) SEM images were taken to characterize the features in the casting. Image processing steps applied on SEM and optical micrographs included median and range filters, dilation, erosion, and a hole-closing function. Measurements were done on different image pixel resolutions that ranged from 3 to 35 pixel/μm. Pixel resolutions below 6 px/μm were too low for the algorithm to distinguish the phases from each other. At resolutions higher than 6 px/μm, the volume fraction of primary α-Al and the line intercept count curves plateaued. Within this range, comparable results were obtained validating the assumption that there is a range of image pixel resolution relative to the size of the casting features at which stereology measurements become independent of the image resolution. Volume fraction within this curve plateau was consistent with the manual measurements while the line intercept count was significantly higher using the computerized technique for all resolutions. This was attributed to the ragged edges of some primary α-Al; hence, the algorithm still needs some improvements. Further validation of the code using other castings or alloys with known phase amount and size may also be beneficial.

  12. High Pressure Supersonic Gas Jet Fueling on NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V; Bell, M; Blanchard, W; Dong, J; Gernhardt, R; Kaita, R; Kugel, H; Provost, T; Roquemore, A; Sichta, P


    A supersonic gas injector (SGI) has been developed for fueling and diagnostic applications on NSTX. The SGI is comprised of a small de Laval converging-diverging graphite nozzle, a commercial piezoelectric gas valve, and a diagnostic package, all mounted on a movable probe at a low field side midplane port location. The nozzle operated in a pulsed regime at room temperature, reservoir deuterium pressure up to 2500 Torr (50 PSIA), flow rate up to 65 Torr l /s (4.55e21 particles/s), and a measured Mach number of about 4. In initial experiments the SGI was used for fueling of ohmic and 2 - 6 MW NBI-heated L- and H-mode plasmas. Reliable H-mode access was obtained with SGI fueling, with a fueling efficiency in the range 0.1 - 0.3. Good progress was also made toward a controlled density SGI-fueled H-mode plasma scenario with the flow rate of the uncontrolled high field side (HFS) gas injector reduced by up to 20. These experiments motivated a number of SGI upgrades: (1) the maximum plenum pressure has been increased to 5000 Torr (100 PSIA), (2) the plenum pressure volume has been doubled, (3) the gas delivery system has been changed to allow for injection of various gases, (4) a multi-pulse capability has been implemented. As a result of the upgrades, the maximum flow rate increased to about 130 Torr l /s. Laboratory gas jet characterization tests indicated a Mach number of about 4 with H2 and D2, and 4-6 with He and N2. Plasma experiments demonstrated the high-pressure gas jet fueling compatibility with H-mode plasmas, high fueling efficiency (0.1 - 0.3), and high SOL penetration.

  13. High pressure {sup 31}P NMR spectroscopy on guanine nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Spoerner, Michael; Karl, Matthias; Lopes, Pedro; Hoering, Marcus; Loeffel, Karoline; Nuehs, Andrea; Adelsberger, Joseph; Kremer, Werner; Kalbitzer, Hans Robert, E-mail: [University of Regensburg, Centre of Magnetic Resonance in Chemistry and Biomedicine, Institute of Biophysics and Physical Biochemistry (Germany)


    The {sup 31}P NMR pressure response of guanine nucleotides bound to proteins has been studied in the past for characterizing the pressure perturbation of conformational equilibria. The pressure response of the {sup 31}P NMR chemical shifts of the phosphate groups of GMP, GDP, and GTP as well as the commonly used GTP analogs GppNHp, GppCH{sub 2}p and GTPγS was measured in the absence and presence of Mg{sup 2+}-ions within a pressure range up to 200 MPa. The pressure dependence of chemical shifts is clearly non-linear. For all nucleotides a negative first order pressure coefficient B{sub 1} was determined indicating an upfield shift of the resonances with pressure. With exception of the α-phosphate group of Mg{sup 2+}·GMP and Mg{sup 2+}·GppNHp the second order pressure coefficients are positive. To describe the data of Mg{sup 2+}·GppCH{sub 2}p and GTPγS a Taylor expansion of 3rd order is required. For distinguishing pH effects from pressure effects a complete pH titration set is presented for GMP, as well as GDP and GTP in absence and presence of Mg{sup 2+} ions using indirect referencing to DSS under identical experimental conditions. By a comparison between high pressure {sup 31}P NMR data on free Mg{sup 2+}-GDP and Mg{sup 2+}-GDP in complex with the proto-oncogene Ras we demonstrate that pressure induced changes in chemical shift are clearly different between both forms.

  14. Digital valve for high pressure high flow applications (United States)

    Badescu, Mircea; Sherrit, Stewart; Lewis, Derek; Bao, Xiaoqi; Bar-Cohen, Yoseph; Hall, Jeffery L.


    To address the challenges, which are involved with the development of flow control valves that can meet high demand requirements such as high pressure, high flow rate, limited power and limited space, the authors have conceived a novel design configuration. This design consists of a digitalized flow control valve with multipath and multistage pressure reduction structures. Specifically, the valve is configured as a set of parallel flow paths from the inlet to the outlet. A choke valve controls the total flow rate by digitally opening different paths or different combination of the paths. Each path is controlled by a poppet cap valve basically operated in on-off states. The number of flow states is 2N where N is the number of flow paths. To avoid erosion from sand in the fluid and high speed flow, the seal area of the poppet cap valve is located at a distance from the flow inlet away from the high speed flow and the speed is controlled to stay below a predefined erosion safe limit. The path is a multistage structure composed of a set of serial nozzles-expansion chambers that equally distribute the total pressure drop to each stage. The pressure drop of each stage and, therefore, the flow speed at the nozzles and expansion chambers is controlled by the number of stages. The paths have relatively small cross section and could be relatively long for large number of stages and still fit in a strict annular space limit. The paper will present the design configuration, analysis and preliminary test results.

  15. High-pressure optical spectroscopy study of natural siderite (United States)

    Taran, Michail N.; Müller, Jan; Friedrich, Alexandra; Koch-Müller, Monika


    Optical absorption spectra of siderite were taken across the high-spin (HS)-to-low-spin (LS) transition up to a pressure of 70 GPa in the spectral range between 28,500 and 10,000 cm-1. Up to a pressure of 44.5 GPa, a pair of two overlapping broad bands was observed that are caused by the electronic spin-allowed 5 T 2g → 5 E g transition of the octahedrally coordinated Fe2+. Furthermore, eight spin-forbidden bands are observable at high pressures up to 44.5 GPa, but they are gradually overlapped by the increasing high-energy absorption edge to be tracked down over the whole pressure range. Due to the HS-to-LS-spin-state transition of Fe2+ between 44.5 and 47.6 GPa, a new broad intense absorption band appears on the steep background of the edge, which is assigned to the electronic spin-allowed 1 A 1g → 1 T 1g transition of octahedral Fe2+ in LS configuration. We estimated a mean octahedral module K_{oct}^{spectr} of Fe2+ in the LS state for pressure range 47.6-65.5 GPa as 263 (17) GPa. Especially, a strong intensification of the spin-allowed and spin-forbidden bands with increasing pressure is observed in the HS state. This is assumed to be caused by the borrowing of intensity from the UV absorption bands, which are allowed by the Laporte selection rule and are caused by electronic ligand-to-metal charge-transfer transitions.

  16. Demonstrating the Importance of Bubbles and Viscosity on Volcanic Eruptions (United States)

    Namiki, A.


    The behavior of bubbles (exsolved volatile from magma) and viscosity of magma are important parameters that influence volcanic eruptions. Exsolved volatiles increase the volume of magma and reduce its density so that magma has sufficient volume and buoyancy force to erupt. Volatiles exsolve through nucleation and growth by diffusion and bubbles can expand as pressure is reduced. The time scale of diffusion depends on the viscosity of surrounding magma, and the expansion time scale of a bubble is also depends on the viscosity of magma. These control the time scale for volume change. If bubbles segregate from magma and collapse, the magma might not able to expand sufficiently to erupt violently. Whether a bubble can segregate from the liquid part of magma is also depends on viscosity of magma. In this poster, I introduce a straightforward demonstration to show the importance of bubbles and viscosity of magma on volcanic eruptions. To make bubbles, I use baking soda (NaHCO3) and citric acid. Reaction between them generates carbon dioxide (CO2) to make bubbles. I make citric acid solution gel by using agar at the bottom of a transparent glass and pour baking soda disolved corn syrup on top of the agar. This situation is a model of basally heated magma chamber. When water disolved magma (baking soda disolved corn syrup) receives sufficient heat (citric acid) bubbles are generated. I can change viscosity of corn syrup by varying the concentration of water. This demonstration shows how viscosity controls the time scale of volume change of bubbly magma and the distribution of bubbles in the fluid. In addition it helps to understand the important physical processes in volcanic eruption: bubble nucleation, diffusion grows, expansion, and bubble driving convection. I will perform a live demonstration at the site of the poster.

  17. Intrinsic viscosity of polymers and biopolymers measured by microchip. (United States)

    Lee, Jinkee; Tripathi, Anubhav


    Intrinsic viscosity provides insight to molecular structure and interactions in solution. A new microchip method is described for fast and accurate measurements of viscosity and intrinsic viscosity of polymer and biopolymer solutions. Polymer samples are diluted with solvent in the microfluidic chip by imposing pressure gradients across the channel network. The concentration and flow dilutions of the polymer sample are calculated from the fluorescent signals recorded over a range of dilutions. The viscosities at various polymer dilutions are evaluated using mass and momentum balances in the pressure-driven microchannel flow. The technique is particularly important to many chemical, biological, and medical applications where sample is available in very small quantities. The intrinsic viscosity experiments were performed for three classes of polymer solutions: (a) poly(ethylene glycol), polymers with linear hydrocarbon chains; (b) bovine serum albumin, biopolymer chains with hydrophobic and hydrophilic amino acids, and (c) DNA fragments, biological macromolecules with double-stranded polymeric chains. The measured values of intrinsic viscosity agree remarkably well with the available data obtained using different methods. The data exhibit power law behavior for molecular weight as described by the Mark-Houwink-Sakurada equation. Experiments were performed to understand the effect of solvent quality and salt concentration on molecular conformations and the intrinsic viscosity of the polymers. This method offers a new way to study the conformational changes in proteins and DNA solutions in various buffer conditions such as pH, ionic strength, and surfactants. The effects of shear rate in the microchannel and mixing time on the accuracy and limitation of the measurement method are discussed.

  18. Predicting human blood viscosity in silico

    Energy Technology Data Exchange (ETDEWEB)

    Fedosov, Dmitry A. [Inst. of Complex Systems and Inst. for Advanced Simulation, Julich (Germany); Brown Univ., Providence, RI (United States); Pan, Wenxiao [Brown Univ., Providence, RI (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Caswell, Bruce [Brown Univ., Providence, RI (United States); Gompper, Gerhard [Inst. of Complex Systems and Inst. for Advanced Simulation, Julich (Germany); Karniadakis, George E. [Brown Univ., Providence, RI (United States)


    Cellular suspensions such as blood are a part of living organisms and their rheological and flow characteristics determine and affect majority of vital functions. The rheological and flow properties of cell suspensions are determined by collective dynamics of cells, their structure or arrangement, cell properties and interactions. We study these relations for blood in silico using a mesoscopic particle-based method and two different models (multi-scale/low-dimensional) of red blood cells. The models yield accurate quantitative predictions of the dependence of blood viscosity on shear rate and hematocrit. We explicitly model cell aggregation interactions and demonstrate the formation of reversible rouleaux structures resulting in a tremendous increase of blood viscosity at low shear rates and yield stress, in agreement with experiments. The non-Newtonian behavior of such cell suspensions (e.g., shear thinning, yield stress) is analyzed and related to the suspension’s microstructure, deformation and dynamics of single cells. We provide the flrst quantitative estimates of normal stress differences and magnitude of aggregation forces in blood. Finally, the flexibility of the cell models allows them to be employed for quantitative analysis of a much wider class of complex fluids including cell, capsule, and vesicle suspensions.

  19. Shear viscosity of the quark matter


    Iwasaki, Masaharu; Ohnishi, Hiromasa; Fukutome, Takahiko


    We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

  20. Effects of iron oxidation state on viscosity, lunar composition 15555 (United States)

    Cukierman, M.; Uhlmann, D. R.


    The viscous flow behavior of a 9.6-kg lunar rock containing 22.5 wt.% FeO was studied in the temperature ranges from 620 to 700 C and from 1215 to 1400 C. The material was synthesized under mildy reducing conditions to simulate the Fe(2+)/total Fe ratio of the lunar environment. The effect of iron oxidation state on flow behavior in the high viscosity region is studied for specimens of the 15555 composition with Fe(2+) concentration ratios of 0.94, 0.76, and 0.20. A change in ratio from 0.94 to 0.76 had no observable effect on viscosity, whereas a change from 0.76 to 0.20 was accompanied by a drastic increase in viscosity (some three orders of magnitude) at a given temperature, but without changing the form of the variation of viscosity with temperature. The flow behavior is analyzed as a function of the structural features of the glasses.

  1. Density and viscosity of lipids under pressure (United States)

    There is a lack of data for the viscosity of lipids under pressure. The current report is a part of the effort to fill this gap. The viscosity, density, and elastohydrodynamic film thicknesses of vegetable oil (HOSuO) were investigated. Pressure–viscosity coefficients (PVC) of HOSuO at different tem...

  2. Effect of viscosity on learned satiation

    NARCIS (Netherlands)

    Mars, M.; Hogenkamp, P.S.; Gosses, A.M.; Stafleu, A.; Graaf,


    A higher viscosity of a food leads to a longer orosensory stimulation. This may facilitate the learned association between sensory signals and metabolic consequences. In the current study we investigated the effect of viscosity on learned satiation. In two intervention groups a low viscosity (LV)

  3. Mechanism of viscosity modification in multigrade oils

    Energy Technology Data Exchange (ETDEWEB)

    Song, W.R.


    Multigrade motor oil viscosity modifiers such as acrylates, polyisobutylene, and olefin copolymers were examined to compare the basic physical properties of these polymers. Results of viscosity measurements and hydrodynamic volume changes are tabulated and discussed. Discussions are also included on temporary viscosity losses in polymer solutions. (JRD)

  4. Dark goo: Bulk viscosity as an alternative to dark energy

    CERN Document Server

    Gagnon, Jean-Sebastien


    We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective" pressure containing the bulk viscosity. For a sufficiently large bulk viscosity, the effective pressure becomes negative and could mimic a dark energy equation of state. Our microscopic model includes self-interacting spin-zero particles (for which the bulk viscosity is known) that are added to the usual energy content of the universe. We study both background equations and linear perturbations in this model. We show that a dark energy behavior is obtained for reasonable values of the two parameters of the model (i.e. the mass and coupling of the spin-zero particles) and that linear perturbations are well-behaved. There is no apparent fine tuning involved. We also discuss the conditions under which hydrodynamics holds, in particular that the spin-zero particles must be in local eq...

  5. Dynamic viscosity study of barley malt and chicory concentrates

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov


    Full Text Available The purpose of research is to find optimal conditions for dispersing and subsequent dehydration of liquid food environments in the nozzle spray drying chamber through the study of dynamic changes in viscosity according to temperature, velocities gradients and dry residue content. The objects of study were roasted chicory and malt barley concentrates with dry residue content of 20, 40, 60 and 80%. Research of dynamic viscosity were carried out at the measuring complex based on the rotational viscometer Rheotest II, analog-to-digital converter, module Laurent and a personal computer with a unique software that allows to record in real time (not only on a tape recorder, but also in the form of graphic files the behavior of the viscosity characteristics of concentrates. Registration of changes of dynamic viscosity was carried out at a shear rate gradient from 1,0 с -1 to 27,0 с -1 and the products temperature thermostating : 35, 55, 75˚ C. The research results are presented in the form of graphic dependences of effective viscosity on shear rate and flow curves (dependencies of shear stresses on the velocity gradient, which defined flow regimes, the optimal modes of dispersion concentrates into spray dryer chambers in obtaining of powdered semi-finished products and instanting were found: dry residue content - 40 %, concentrate temperature - 75 ˚C, velocity gradient in the air channel of the nozzle at least 20 c-1

  6. Shear viscosity of nuclear matter (United States)

    Magner, A. G.; Gorenstein, M. I.; Grygoriev, U. V.; Plujko, V. A.


    Shear viscosity η is calculated for the nuclear matter described as a system of interacting nucleons with the van der Waals (VDW) equation of state. The Boltzmann-Vlasov kinetic equation is solved in terms of the plane waves of the collective overdamped motion. In the frequent-collision regime, the shear viscosity depends on the particle-number density n through the mean-field parameter a , which describes attractive forces in the VDW equation. In the temperature region T =15 -40 MeV, a ratio of the shear viscosity to the entropy density s is smaller than 1 at the nucleon number density n =(0.5 -1.5 ) n0 , where n0=0.16 fm-3 is the particle density of equilibrium nuclear matter at zero temperature. A minimum of the η /s ratio takes place somewhere in a vicinity of the critical point of the VDW system. Large values of η /s ≫1 are, however, found in both the low-density, n ≪n0 , and high-density, n >2 n0 , regions. This makes the ideal hydrodynamic approach inapplicable for these densities.

  7. Nonlocal viscosity kernel of mixtures (United States)

    Smith, Ben; Hansen, J. S.; Todd, B. D.


    In this Brief Report we investigate the multiscale hydrodynamical response of a liquid as a function of mixture composition. This is done via a series of molecular dynamics simulations in which the wave-vector-dependent viscosity kernel is computed for three mixtures, each with 7-15 different compositions. We observe that the viscosity kernel is dependent on composition for simple atomic mixtures for all the wave vectors studied here; however, for a molecular mixture the kernel is independent of composition for large wave vectors. The deviation from ideal mixing is also studied. Here it is shown that the Lorentz-Berthelot interaction rule follows ideal mixing surprisingly well for a large range of wave vectors, whereas for both the Kob-Andersen and molecular mixtures large deviations are found. Furthermore, for the molecular system the deviation is wave-vector dependent such that there exists a characteristic correlation length scale at which the ideal mixing goes from underestimating to overestimating the viscosity.

  8. Viscosity of Earth's Outer Core

    CERN Document Server

    Smylie, D E


    A viscosity profile across the entire fluid outer core is found by interpolating between measured boundary values, using a differential form of the Arrhenius law governing pressure and temperature dependence. The discovery that both the retrograde and prograde free core nutations are in free decay (Palmer and Smylie, 2005) allows direct measures of viscosity at the top of the outer core, while the reduction in the rotational splitting of the two equatorial translational modes of the inner core allows it to be measured at the bottom. We find 2,371 plus/minus 1,530 Pa.s at the top and 1.247 plus/minus 0.035 x 10^11 Pa.s at the bottom. Following Brazhkin (1998) and Brazhkin and Lyapin (2000) who get 10^2 Pa.s at the top, 10^11 Pa.s at the bottom, by an Arrhenius extrapolation of laboratory experiments, we use a differential form of the Arrhenius law to interpolate along the melting temperature curve to find a viscosity profile across the outer core. We find the variation to be closely log-linear between the meas...

  9. Coexistence of a metastable double hcp phase in bcc–fcc structure transition of Te under high pressure (United States)

    Akahama, Yuichi; Okawa, Naoki; Sugimoto, Toshiyuki; Fujihisa, Hiroshi; Hirao, Naoshisa; Ohishi, Yasuo


    The structural phase transitions of tellurium (Te) are investigated at pressures of up to 330 GPa at 298 K using an X-ray powder diffraction technique. In the experiments, it was found that the high-pressure bcc phase (Te-V) transitioned to the fcc phase (Te-VI) at 99 GPa, although a double hcp phase (dhcp) coexisted with the fcc phase. As the pressure was increased and decreased, the dhcp phase vanished at 255 and 100 GPa, respectively. These results suggest that the dhcp phase is metastable at 298 K and the structure of the highest-pressure phase of Te is fcc. The present results provide important information regarding the high-pressure behavior of group-16 elements.

  10. Molecular basis of high viscosity in concentrated antibody solutions: Strategies for high concentration drug product development. (United States)

    Tomar, Dheeraj S; Kumar, Sandeep; Singh, Satish K; Goswami, Sumit; Li, Li


    Effective translation of breakthrough discoveries into innovative products in the clinic requires proactive mitigation or elimination of several drug development challenges. These challenges can vary depending upon the type of drug molecule. In the case of therapeutic antibody candidates, a commonly encountered challenge is high viscosity of the concentrated antibody solutions. Concentration-dependent viscosity behaviors of mAbs and other biologic entities may depend on pairwise and higher-order intermolecular interactions, non-native aggregation, and concentration-dependent fluctuations of various antibody regions. This article reviews our current understanding of molecular origins of viscosity behaviors of antibody solutions. We discuss general strategies and guidelines to select low viscosity candidates or optimize lead candidates for lower viscosity at early drug discovery stages. Moreover, strategies for formulation optimization and excipient design are also presented for candidates already in advanced product development stages. Potential future directions for research in this field are also explored.

  11. Exhumation of (ultra-high-pressure terranes: concepts and mechanisms

    Directory of Open Access Journals (Sweden)

    C. J. Warren


    Full Text Available The formation and exhumation of high and ultra-high-pressure, (UHP, rocks of crustal origin appears to be ubiquitous during Phanerozoic plate subduction and continental collision events. Exhumation of (UHP material has been shown in some orogens to have occurred only once, during a single short-lived event; in other cases exhumation appears to have occurred multiple discrete times or during a single, long-lived, protracted event. It is becoming increasingly clear that no single exhumation mechanism dominates in any particular tectonic environment, and the mechanism may change in time and space within the same subduction zone. Subduction zone style and internal force balance change in both time and space, responding to changes in width, steepness, composition of subducting material and velocity of subduction. In order for continental crust, which is relatively buoyant compared to the mantle even when metamorphosed to (UHP assemblages, to be subducted to (UHP conditions, it must remain attached to a stronger and denser substrate. Buoyancy and external tectonic forces drive exhumation, although the changing spatial and temporal dominance of different driving forces still remains unclear. Exhumation may involve whole-scale detachment of the terrane from the subducting slab followed by exhumation within a subduction channel (perhaps during continued subduction or a reversal in motion of the entire plate (eduction following the removal of a lower part of the subducting slab. Weakening mechanisms that may be responsible for the detachment of deeply subducted crust from its stronger, denser substrate include strain weakening, hydration, melting, grain size reduction and the development of foliation. These may act locally to form narrow high-strain shear zones separating stronger, less-strained crust or may act on the bulk of the subducted material, allowing whole-scale flow. Metamorphic reactions, metastability and the composition of the subducted crust

  12. Melting in the Fe-Si System at High Pressures (United States)

    Campbell, A. J.; Fischer, R. A.; Reaman, D. M.; Prakapenka, V.; Dera, P. K.


    The density of Earth's core is less dense than that of pure iron, indicating the presence of a light element component that not only reduces the density of the outer core but lowers its melting point as well. Among the most likely candidates for this light element component are Si, S, C, and O; it is important to know the high-pressure, high-temperature properties of iron alloyed with these elements to understand the nature of Earth's core. Here we report on melting experiments in the Fe-Si system to pressures reaching those in the outermost core. Synchrotron X-ray diffraction experiments were performed on laser-heated diamond anvil cell samples at beamline 13-ID-D of the Advanced Photon Source. Temperatures were measured spectroradiometrically, and melting was determined by the appearance and disappearance of diffuse scattering from the melt during heating and cooling cycles. Two compositions, Fe-9Si and Fe-16Si, were studied. Our results are compatible with recent studies [1,2] on similar compositions but lower pressures. At 137 GPa we bracket the melting temperature of Fe-16Si between 3530 and 3800 K; accordingly, 3520 K is a minimum temperature for the outermost core if it were to consist exclusively of Fe-Si alloy. At these pressures the stable solid phase assemblage for Fe-16Si is a mixture of Fe-rich hcp alloy and a more Si-rich alloy with the B2 structure (Fischer et al., this volume [3]). We observe that the hcp phase disappears while the B2 phase persists at the 138 GPa melting point, implying that the Fe-Si eutectic composition at that pressure lies below 16 wt% Si. By comparison, the maximum Si content of a Fe-Si core is 12 wt%, based on comparison of recent equation of state measurements of Fe-Si alloy [3] with a seismological model of the Earth. [1] Morard et al., PCM 2011. [2] Asanuma et al., PCM 2010. [3] Fischer et al., Fall AGU 2011.

  13. High pressure HC1 conversion of cellulose to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Antonoplis, Robert Alexander [Univ. of California, Berkeley, CA (United States); Blanch, Harvey W. [Univ. of California, Berkeley, CA (United States); Wilke, Charles R. [Univ. of California, Berkeley, CA (United States)


    The production of ethanol from glucose by means of fermentation represents a potential long-range alternative to oil for use as a transportation fuel. Today's rising oil prices and the dwindling world supply of oil have made other fuels, such as ethanol, attractive alternatives. It has been shown that automobiles can operate, with minor alterations, on a 10% ethanol-gasoline mixture popularly known as gasohol. Wood has long been known as a potential source of glucose. Glucose may be obtained from wood following acid hydrolysis. In this research, it was found that saturating wood particles with HCl gas under pressure was an effective pretreatment before subjecting the wood to dilute acid hydrolysis. The pretreatment is necessary because of the tight lattice structure of cellulose, which inhibits dilute acid hydrolysis. HCl gas makes the cellulose more susceptible to hydrolysis and the glucose yield is doubled when dilute acid hydrolysis is preceded by HCl saturation at high pressure. The saturation was most effectively performed in a fluidized bed reactor, with pure HCl gas fluidizing equal volumes of ground wood and inert particles. The fluidized bed effectively dissipated the large amount of heat released upon HCl absorption into the wood. Batch reaction times of one hour at 314.7 p.s.i.a. gave glucose yields of 80% and xylose yields of 95% after dilute acid hydrolysis. A non-catalytic gas-solid reaction model, with gas diffusing through the solid limiting the reaction rate, was found to describe the HCl-wood reaction in the fluidized bed. HCl was found to form a stable adduct with the lignin residue in the wood, in a ratio of 3.33 moles per mole of lignin monomer. This resulted in a loss of 0.1453 lb. of HCl per pound of wood. The adduct was broken upon the addition of water. A process design and economic evaluation for a plant to produce 214 tons per day of glucose from air-dried ground Populus tristi gave an estimated glucose cost of 15.14 cents per pound

  14. Influence of type of microorganism, food ingredients and food properties on high-pressure carbon dioxide inactivation of microorganisms. (United States)

    Garcia-Gonzalez, L; Geeraerd, A H; Elst, K; Van Ginneken, L; Van Impe, J F; Devlieghere, F


    High pressure carbon dioxide (HPCD) treatment is currently considered as an attractive non-thermal process for preserving food. Industrial application of this technique requires, among others, systematic (quantitative) data on the inactivation of food relevant pathogenic and spoilage microorganisms, and in-depth information on the effect that the composition and the properties of a food matrix have on the inactivation efficacy. The first objective of this study, therefore, is to evaluate and compare the HPCD susceptibility of several food pathogens and spoilage microorganisms under the same treatment conditions. In the second part, the influence of different food components (NaCl, oil, starch, whey protein and emulsifier) and food properties (pH, fluid viscosity and water activity) on the inactivation efficacy of HPCD was determined. For the first aim, a range of Gram-negative and Gram-positive bacteria, yeasts and spores were treated with pressurized CO(2) at 10.5 MPa and 35 degrees C during 20 min. Bacterial susceptibility towards HPCD treatments followed the sequence Gram-negative approximately Gram-positive>yeasts>spores and appeared to be related to the acid resistance of the organisms. To study the effect of different food compounds on HPCD inactivation, the reduction degree of Pseudomonas fluorescens was determined in media with and without these components at 10.5 MPa and 35 degrees C after 5 or 20 min, depending on the tested component. NaCl and the emulsifiers Tween 80 and sucrose stearate enhanced bacterial reduction, while oil reduced the bactericidal efficacy of HPCD. Starch and whey proteins did not influence inactivation. Finally, the influence of pH, fluid viscosity and water activity was investigated by determining the reduction of P. fluorescens at 10.5 MPa and 35 degrees C in suspensions from which the pH, viscosity and water activity were adjusted with respectively NaOH or HCl, gelatin or polyethylene glycol, and sucrose, NaCl or glycerol

  15. The preservation of high-pressure rocks during exhumation: metagranites and metapelites (United States)

    Proyer, Alexander


    Metagranites in the NKFMASH system require external hydration during prograde high-pressure metamorphism in order to equilibrate to ambient HP conditions by producing more siliceous muscovite. Any lack of external fluid or the disappearance of biotite stops re-equilibration and thus prevents recording of high-pressure conditions. The same hydration reactions cause dehydration during exhumation. Orthogneiss from shear zones or adjacent to metapelites and metabasites will take up external fluid during subduction and record the highest P- T conditions, but will also be the first to dehydrate upon exhumation, now hydrating other lithologies and probably refuelling shearzones. The (de)hydration behavior of Ca-bearing metagranitoids is similar to that in the Ca-free system. However, the anorthite component of plagioclase decomposes with increasing pressure to form either (clino)zoisite or a grossular-rich garnet. Both reactions are fluid-consuming. If H 2O is supplied from an external source, the garnet-bearing assemblage can record P- T conditions up to very high pressures, but dehydrates again during heating and/or decompression to form a more Fe-rich garnet and Al-rich mica(s). The garnet compositions observed in natural HP-metagranites are mostly too Fe-rich to be formed in the presence of an H 2O-rich fluid. N(C)KFMASH metapelites generally have a more complex mineralogy and succession of mineral assemblages along a P- T path. The H 2O contained in hydrous silicates like chlorite and chloritoid is only partly released, but partly transferred to other minerals like paragonite, glaucophane or phengite during subduction and further dehydration during exhumation is common. The mineral assemblage preserved by the rock may then record P- T conditions way below those of the actual pressure and temperature peak of the path. Contouring of the P- T pseudosection of a specific metapelite composition with mode isopleths for H 2O shows which P- T conditions along a given path

  16. The High-Pressure Assemblage Majorite-Pyrope Solid Solution + Magnesiowustite: A New Constraint on the High Pressure and Temperature History of Shock Melt Veins in Chondrites (United States)

    Chen, M.; Sharp, T. G.; El Goresy, A.; Wopenka, B.; Xie, X.


    Two coexisting distinct high pressure assemblages were discovered in shock melt veins of the Sixiangkou (L6) chondrite: (1) majorite-pyrope(sub)ss + magnesiowustite and (2) ringwoodite + low-Ca majorite. The majorite-pyrope(sub)ss + magnesiowustite evidently crystallized from a dense melt of bulk Sixiangkou composition that was produced by shock-fusion under high pressures and temperatures, whereas ringwoodite and low-Ca majorite in the second assemblage were formed by solid state transformation of olivine and low-Ca pyroxene originally present in the meteorite. The two high pressure assemblages indicate a duration over a time on the order of seconds under a high pressure (20-24 GPa) and high temperature (2050-2300 degrees C) regime.

  17. Influence of activation and germination on high pressure inactivation of ascospores of the mould Eurotium repens. (United States)

    Eicher, R; Ludwig, H


    We investigated heat activation and germination of Eurotium repens ascospores to follow high pressure inactivation. Activation energy and entropy values strengthen the idea of protein denaturation as the underlying mechanism of heat activation. Preceding activation, germination or a combination of both affected high pressure inactivation in different ways. Activation followed immediately by high pressure treatment led to the most efficient improvement in inactivation. However, a pause after activation caused a partial re-establishment of the spores' stability and less efficient high pressure inactivation. Germination stabilized the spores against high pressure. A combined treatment of activation and germination led to an initially fast inactivation, but compared to high pressure treatment of only activated spores the time course of inactivation was slowed down.

  18. Coherent Lamellar Growth of Akimotoite within Enstatite Host at High Pressure and Temperature (United States)

    Lockridge, J.; Sharp, T. G.; Hu, J.


    To constrain models of the rheology and dynamic behavior of subducting oceanic lithosphere within the mantle transition zone, it is important to understand the mechanisms by which the major mineralogical components of the slab transform to their high-pressure polymorphs. Despite being the second most abundant component of the upper mantle, the mechanisms of polymorphic phase transformations in pyroxene remain poorly understood. In subducting oceanic lithosphere, which is colder than the surrounding mantle, akimotoite would be stable relative to majorite and the polymorphic reaction to akimotoite would be kinetically favored over disproportionation reactions to ringwoodite or wadsleyite plus stishovite. There are two transformation mechanisms that have been observed in experiments studying polymorphic transformation of mantle silicates. Heterogeneous nucleation and interface controlled growth is the most commonly observed mechanism, with product phases typically growing as incoherent, granular rims. A second, shear-induced mechanism is characterized by coherent lamellar growth of high-pressure phases on stacking faults within the host grain. Coherent lamellar intergrowth has been observed experimentally in (Mg,Fe)2SiO4 olivine (Kerschhofer 1996, 1998) and within shocked chondritic meteorites for both olivine (Chen et al., 2004) and enstatite (Tomioka and Fujino 1997, 1999). Tomioka (2007) modeled a shear-induced mechanism for the enstatite-akimotoite transition, but this mechanism has not been observed experimentally. We are investigating transformation reactions and kinetics of natural Mg0.9Fe0.1SiO3 enstatite. Within a sample transformed at 20GPa and 1400°C, we observe akimotoite lamellae within the enstatite host. Using transmission electron microscopy, we confirm the coherent, topotaxial relationship between the akimotoite and enstatite as modeled in Tomioka (2007). These findings suggest that shear-induced intracrystalline transformation of enstatite to

  19. Effective viscosity of actively swimming algae suspensions (United States)

    Ewoldt, Randy; Caretta, Lucas; Chengala, Anwar; Sheng, Jian


    Suspensions of actively swimming microorganisms exhibit an effective viscosity which may depend on volume fraction, cell shape, and the nature of locomotion (e.g. "pushers" vs. "pullers"). Here we report experimental measurements of shear viscosity for suspensions of unicellular green algae (Dunaliella primolecta, a biflagellated "puller"). We use a cone-and-plate rheometer to measure the dynamic shear viscosity for both motile and non-motile suspensions of D. primolecta. Viscosity increases with concentration for both cases, but the active suspensions of "pullers" have a comparatively lower effective viscosity than passive suspensions. This observation contrasts recently proposed theories which predict that "pullers" should instead have a higher viscosity than non-motile suspensions. Additionally, we observe shear-induced migration of active suspensions and consider its impact on the resulting effective shear viscosity.

  20. Development and Evaluation of a Prototype Wheeled Ultra-High Pressure Extinguisher System with Novec 1230 (United States)


    AFCEC-CX-TY-TR-2016-0004 Development and Evaluation of a Prototype Wheeled Ultra-High Pressure Extinguisher System with Novec 1230 Dr. Mark Enlow...Report 1 Nov 2014 -- 1 Jul 2015 Development and Evaluation of a Prototype Wheeled Ultra-High Pressure Extinguisher System With Novec 1230 FA8051-14-P...Halon 1211 flightline extinguisher , the Air Force Civil Engineer Center (AFCEC) developed and evaluated a prototype wheeled ultra-high pressure

  1. Characterization of high-pressure RTM processes for manufacturing of high performance composites


    R. Chaudhari; Karcher, M.; Elsner, P.; Henning, F


    The current paper addresses new variants of the RTM process namely High Pressure-Injection Resin Transfer Molding (HP-IRTM) and High Pressure - Compression Resin Transfer Molding (HP-CRTM) for manufacturing of continuous fiber reinforced composites with high fiber volume content. Both these process utilize High Pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The objective of the proposed study was to...

  2. Lycopene degradation, isomerization and in vitro bioaccessibility in high pressure homogenized tomato puree containing oil: effect of additional thermal and high pressure processing. (United States)

    Knockaert, Griet; Pulissery, Sudheer K; Colle, Ines; Van Buggenhout, Sandy; Hendrickx, Marc; Loey, Ann Van


    In the present study, the effect of equivalent thermal and high pressure processes at pasteurization and sterilization intensities on some health related properties of high pressure homogenized tomato puree containing oil were investigated. Total lycopene concentration, cis-lycopene content and in vitro lycopene bioaccessibility were examined as health related properties. Results showed that pasteurization hardly affected the health related properties of tomato puree. Only the formation of cis-lycopene during intense thermal pasteurization was observed. Sterilization processes on the other hand had a significant effect on the health related properties. A significant decrease in total lycopene concentration was found after the sterilization processes. Next to degradation, significant isomerization was also observed: all-trans-lycopene was mainly converted to 9-cis- and 13-cis-lycopene. High pressure sterilization limited the overall lycopene isomerization, when compared to the equivalent thermal sterilization processes. The formation of 5-cis-lycopene on the other hand seemed to be favoured by high pressure. The in vitro lycopene bioaccessibility of high pressure homogenized tomato puree containing oil was decreased during subsequent thermal or high pressure processing, whereby significant changes were observed for all the sterilization processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Carbonate mineral dissolution kinetics in high pressure experiments (United States)

    Dethlefsen, F.; Dörr, C.; Schäfer, D.; Ebert, M.


    The potential CO2 reservoirs in the North German Basin are overlain by a series of Mesozoic barrier rocks and aquifers and finally mostly by Tertiary and Quaternary close-to-surface aquifers. The unexpected rise of stored CO2 from its reservoir into close-to-surface aquifer systems, perhaps through a broken well casing, may pose a threat to groundwater quality because of the acidifying effect of CO2 dissolution in water. The consequences may be further worsening of the groundwater quality due to the mobilization of heavy metals. Buffer mechanisms counteracting the acidification are for instance the dissolution of carbonates. Carbonate dissolution kinetics is comparably fast and carbonates can be abundant in close-to-surface aquifers. The disadvantages of batch experiments compared to column experiments in order to determine rate constants are well known and have for instance been described by v. GRINSVEN and RIEMSDIJK (1992). Therefore, we have designed, developed, tested, and used a high-pressure laboratory column system to simulate aquifer conditions in a flow through setup within the CO2-MoPa project. The calcite dissolution kinetics was determined for CO2-pressures of 6, 10, and 50 bars. The results were evaluated by using the PHREEQC code with a 1-D reactive transport model, applying a LASAGA (1984) -type kinetic dissolution equation (PALANDRI and KHARAKA, 2004; eq. 7). While PALANDRI and KHARAKA (2004) gave calcite dissolution rate constants originating from batch experiments of log kacid = -0.3 and log kneutral = -5.81, the data of the column experiment were best fitted using log kacid = -2.3 and log kneutral = -7.81, so that the rate constants fitted using the lab experiment applying 50 bars pCO2 were approximately 100 times lower than according to the literature data. Rate constants of experiments performed at less CO2 pressure (pCO2 = 6 bars: log kacid = -1.78; log kneutral = -7.29) were only 30 times lower than literature data. These discrepancies in the

  4. High Pressure Atmospheric Sampling Inlet System for Venus or the Gas Giants Project (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a miniaturized high pressure atmospheric sampling inlet system for sample acquisition in extreme planetary environments,...

  5. Widespread subcutaneous emphysema and barotrauma resulting from high pressure gas injection

    National Research Council Canada - National Science Library

    Smith, Barnaby; Brown, Troy


    Widespread subcutaneous emphysema is an unusual emergency presentation. We present a case of accidental high pressure insufflation, the pathophysiology and subsequent medical management in the acute setting...

  6. Computing the viscosity of supercooled liquids: Markov Network model.

    Directory of Open Access Journals (Sweden)

    Ju Li

    Full Text Available The microscopic origin of glass transition, when liquid viscosity changes continuously by more than ten orders of magnitude, is challenging to explain from first principles. Here we describe the detailed derivation and implementation of a Markovian Network model to calculate the shear viscosity of deeply supercooled liquids based on numerical sampling of an atomistic energy landscape, which sheds some light on this transition. Shear stress relaxation is calculated from a master-equation description in which the system follows a transition-state pathway trajectory of hopping among local energy minima separated by activation barriers, which is in turn sampled by a metadynamics-based algorithm. Quantitative connection is established between the temperature variation of the calculated viscosity and the underlying potential energy and inherent stress landscape, showing a different landscape topography or "terrain" is needed for low-temperature viscosity (of order 10(7 Pa·s from that associated with high-temperature viscosity (10(-5 Pa·s. Within this range our results clearly indicate the crossover from an essentially Arrhenius scaling behavior at high temperatures to a low-temperature behavior that is clearly super-Arrhenius (fragile for a Kob-Andersen model of binary liquid. Experimentally the manifestation of this crossover in atomic dynamics continues to raise questions concerning its fundamental origin. In this context this work explicitly demonstrates that a temperature-dependent "terrain" characterizing different parts of the same potential energy surface is sufficient to explain the signature behavior of vitrification, at the same time the notion of a temperature-dependent effective activation barrier is quantified.

  7. Viscosity of Water Interfaces with Hydrophobic Nanopores: Application to Water Flow in Carbon Nanotubes. (United States)

    Shaat, M


    The nanoconfinement of water results in changes in water properties and nontraditional water flow behaviors. The determination of the interfacial interactions between water and hydrophobic surfaces helps in understanding many of the nontraditional behaviors of nanoconfined water. In this study, an approach for the identification of the viscosity of water interfaces with hydrophobic nanopores as a function of the nanopore diameter and water-solid (nanopore) interactions is proposed. In this approach, water in a hydrophobic nanopore is represented as a double-phase water with two distinct viscosities: water interface and water core. First, the slip velocity to pressure gradient ratio of water flow in hydrophobic nanopores is obtained via molecular dynamics (MD) simulations. Then the water interface viscosity is determined via a pressure gradient-based bilayer water flow model. Moreover, the core viscosity and the effective viscosity of water flow in hydrophobic nanopores are derived as functions of the nanopore diameter and water-solid interactions. This approach is utilized to report the interface viscosity, core viscosity, and effective viscosity of water flow in carbon nanotubes (CNTs) as functions of the CNT diameter. Moreover, using the proposed approach, the transition from MD to continuum mechanics is revealed where the bulk water properties are recovered for large CNTs.

  8. Theory and Simulation of A Novel Viscosity Measurement Method for High Temperature Semiconductor (United States)

    Lin, Bochuan; Li, Chao; Ban, Heng; Scripa, Rose; Zhu, Shen; Su, Ching-Hua; Lehoczky, S. L.; Curreri, Peter A. (Technical Monitor)


    The properties of molten semiconductors are good indicators for material structure transformation and hysteresis under temperature variations. Viscosity, as one of the most important properties, is difficult to measure because of high temperature, high pressure, and vapor toxicity of melts. Recently, a novel method was developed by applying a rotating magnetic field to the melt sealed in a suspended quartz ampoule, and measuring the transient torque exerted by rotating melt flow on the ampoule wall. The method was designed to measure viscosity in short time period, which is essential for evaluating temperature hysteresis. This paper compares the theoretical prediction of melt flow and ampoule oscillation with the experimental data. A theoretical model was established and the coupled fluid flow and ampoule torsional vibration equations were solved numerically. The simulation results showed a good agreement with experimental data. The results also showed that both electrical conductivity and viscosity could be calculated by fitting the theoretical results to the experimental data. The transient velocity of the melt caused by the rotating magnetic field was found reach equilibrium in about half a minute, and the viscosity of melt could be calculated from the altitude of oscillation. This would allow the measurement of viscosity in a minute or so, in contrast to the existing oscillation cup method, which requires about an hour for one measurement.

  9. Structural variations of feldspars at high pressure and high temperature


    Kolbus, Lindsay Marie


    Feldspar minerals are framework aluminosilicates that comprise approximately 60 percent of the Earth's crust. The elastic and thermodynamic properties of this important mineral group are needed for the interpretation of seismic wave velocities, for understanding cation partioning patterns and for the determination of phase boundaries and reactions involving feldspars in the Earth's crust. Until recently, no systematic approach has been applied to describe the structural behavior of feldspars ...

  10. Experimental and Modeling Investigation of the Effectof H2S Addition to Methane on the Ignition and Oxidation at High Pressures

    DEFF Research Database (Denmark)

    Gersen, Sander; van Essen, Martijn; Darmeveil, Harry


    The autoignition and oxidation behavior of CH4/H2S mixtures has been studied experimentally in a rapid compression machine (RCM) and a high-pressure flow reactor. The RCM measurements show that the addition of 1% H2S to methane reduces the autoignition delay time by a factor of 2 at pressures ran...... of organosulfuric compounds....

  11. Investigation of the rate-controlling mechanism(s) for high temperature creep and the relationship between creep and melting by use of high pressure as a variable

    Energy Technology Data Exchange (ETDEWEB)


    Using high pressure as a variable, the rate-controlling mechanism for high temperature creep and the relationship between creep and melting is investigated for silicon and nickel. An apparatus is used in which the samples are heated to melting point and subjected to 1 to 3 GigaPascal pressure. The stress behavior of the materials are then studied.

  12. Filter-based Aerosol Measurement Experiments using Spherical Aerosol Particles under High Temperature and High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Young [FNC TECH., Yongin (Korea, Republic of)


    Optical Particle Counter (OPC) is used to provide real-time measurement of aerosol concentration and size distribution. Glass fiber membrane filter also be used to measure average mass concentration. Three tests (MTA-1, 2 and 3) have been conducted to study thermal-hydraulic effect, a filtering tendency at given SiO{sub 2} particles. Based on the experimental results, the experiment will be carried out further with a main carrier gas of steam and different aerosol size. The test results will provide representative behavior of the aerosols under various conditions. The aim of the tests, MTA 1, 2 and 3, are to be able to 1) establish the test manuals for aerosol generation, mixing, sampling and measurement system, which defines aerosol preparation, calibration, operating and evaluation method under high pressure and high temperature 2) develop commercial aerosol test modules applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant. Based on the test results, sampled aerosol particles in the filter indicate that important parameters affecting aerosol behavior aerosols are 1) system temperature to keep above a evaporation temperature of ethanol and 2) aerosol losses due to the settling by ethanol liquid droplet.

  13. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana


    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  14. Drop Spreading with Random Viscosity (United States)

    Xu, Feng; Jensen, Oliver


    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  15. High pressure properties of solid α-O2 (United States)

    Helmy, A.; Kobashi, K.; Etters, R. D.


    The static and dynamic properties of solid oxygen are calculated vs pressure at zero temperature using a pattern recognition optimization scheme and harmonic lattice dynamics method. The lattice parameters, phonon and libron dispersion curves, acoustic sound velocities, compressibility, root mean square translational and librational fluctuations from equilibrium, and the pressure dependence of the intramolecular stretching mode are calculated. It is shown that the attractive magnetic interaction strongly influences the behavior of the solid at all pressures. A soft mode induced phase transition from the monoclinic α structure to an orthorhombic structure is predicted at zero temperature near 6 kbar. No volume change is observed at the transition.

  16. Simultaneous measurement of surface tension and viscosity using freely decaying oscillations of acoustically levitated droplets (United States)

    Kremer, J.; Kilzer, A.; Petermann, M.


    Oscillations of small liquid drops around a spherical shape have been of great interest to scientists measuring physical properties such as interfacial tension and viscosity, over the last few decades. A powerful tool for contactless positioning is acoustic levitation, which has been used to simultaneously determine the surface tension and viscosity of liquids at ambient pressure. In order to extend this acoustic levitation measurement method to high pressure systems, the method is first evaluated under ambient pressure. To measure surface tension and viscosity using acoustically levitated oscillating drops, an image analysis method has to be developed and factors which may affect measurement, such as sound field or oscillation amplitude, have to be analyzed. In this paper, we describe the simultaneous measurement of surface tension and viscosity using freely decaying shape oscillations of acoustically levitated droplets of different liquids (silicone oils AK 5 and AK 10, squalane, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) in air. These liquids vary in viscosity from 2 to about 30 mPa s. An acoustic levitation system, including an optimized standing wave acoustic levitator and a high-speed camera, was used for this study. An image analysis was performed with a self-written Matlab® code. The frequency of oscillation and the damping constant, required for the determination of surface tension and viscosity, respectively, were calculated from the evolution of the equatorial and polar radii. The results and observations are compared to data from the literature in order to analyze the accuracy of surface tension and viscosity determination, as well as the effect of non-spherical drop shape or amplitude of oscillation on measurement.

  17. Simultaneous measurement of surface tension and viscosity using freely decaying oscillations of acoustically levitated droplets. (United States)

    Kremer, J; Kilzer, A; Petermann, M


    Oscillations of small liquid drops around a spherical shape have been of great interest to scientists measuring physical properties such as interfacial tension and viscosity, over the last few decades. A powerful tool for contactless positioning is acoustic levitation, which has been used to simultaneously determine the surface tension and viscosity of liquids at ambient pressure. In order to extend this acoustic levitation measurement method to high pressure systems, the method is first evaluated under ambient pressure. To measure surface tension and viscosity using acoustically levitated oscillating drops, an image analysis method has to be developed and factors which may affect measurement, such as sound field or oscillation amplitude, have to be analyzed. In this paper, we describe the simultaneous measurement of surface tension and viscosity using freely decaying shape oscillations of acoustically levitated droplets of different liquids (silicone oils AK 5 and AK 10, squalane, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) in air. These liquids vary in viscosity from 2 to about 30 mPa s. An acoustic levitation system, including an optimized standing wave acoustic levitator and a high-speed camera, was used for this study. An image analysis was performed with a self-written Matlab® code. The frequency of oscillation and the damping constant, required for the determination of surface tension and viscosity, respectively, were calculated from the evolution of the equatorial and polar radii. The results and observations are compared to data from the literature in order to analyze the accuracy of surface tension and viscosity determination, as well as the effect of non-spherical drop shape or amplitude of oscillation on measurement.

  18. Thermal evolution of high-pressure metamorphic rocks in the Alps

    NARCIS (Netherlands)

    Brouwer, F.M.


    There are two major and currently unresolved issues in Alpine geology concerning the metamorphic evolution of the rocks in the internal zones of the Alps. First, rocks showing evidence for geologically young, high-pressure to very high-pressure metamorphism are now exposed at the Earth's surface,

  19. High pressure studies on uranium and thorium silicide compounds: Experiment and theory

    DEFF Research Database (Denmark)

    Yagoubi, S.; Heathman, S.; Svane, A.


    The actinide silicides ThSi, USi and USi2 have been studied under high pressure using both theory and experiment. High pressure synchrotron X-ray diffraction experiments were performed on polycrystalline samples in diamond anvil cells at room temperature and for pressures up to 54, 52 and 26 GPa,...

  20. 49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems. (United States)


    ... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

  1. Quality and storage-stability of high-pressure preseved green beans

    NARCIS (Netherlands)

    Krebbers, B.; Matser, A.M.; Koets, M.; Berg, van den R.W.


    The effects of high-pressure technology on naturally present microbial flora, texture, color, ascorbic acid content and peroxidase activity of whole green beans were evaluated and compared to conventional preservation techniques. High-pressure processing (HPP) and two-pulse pressure treatment (pHPP)

  2. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.


    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

  3. Study of the thermohydraulics of CO2 discharge from a high pressure reservoir

    NARCIS (Netherlands)

    Ahmad, M.; Osch, M.B.V.; Buit, L.; Florisson, O.; Hulsbosch-Dam, C.; Spruijt, M.; Davolio, F.


    An experimental test set up has been constructed to carry out controlled CO2 release experiments from a high pressure vessel. The test set up is made up of a 500l stainless steel vessel where CO2 can be introduced up to high pressures and where controlled releases can be conducted. The work

  4. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)


    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  5. Transport Signatures of the Hall Viscosity. (United States)

    Delacrétaz, Luca V; Gromov, Andrey


    Hall viscosity is a nondissipative response function describing momentum transport in two-dimensional systems with broken parity. It is quantized in the quantum Hall regime, and contains information about the topological order of the quantum Hall state. Hall viscosity can distinguish different quantum Hall states with identical Hall conductances, but different topological order. To date, an experimentally accessible signature of Hall viscosity is lacking. We exploit the fact that Hall viscosity contributes to charge transport at finite wavelengths, and can therefore be extracted from nonlocal resistance measurements in inhomogeneous charge flows. We explain how to determine the Hall viscosity from such a transport experiment. In particular, we show that the profile of the electrochemical potential close to contacts where current is injected is sensitive to the value of the Hall viscosity.

  6. Viscosity dictates metabolic activity of Vibrio ruber (United States)

    Borić, Maja; Danevčič, Tjaša; Stopar, David


    Little is known about metabolic activity of bacteria, when viscosity of their environment changes. In this work, bacterial metabolic activity in media with viscosity ranging from 0.8 to 29.4 mPas was studied. Viscosities up to 2.4 mPas did not affect metabolic activity of Vibrio ruber. On the other hand, at 29.4 mPas respiration rate and total dehydrogenase activity increased 8 and 4-fold, respectively. The activity of glucose-6-phosphate dehydrogenase (GPD) increased up to 13-fold at higher viscosities. However, intensified metabolic activity did not result in faster growth rate. Increased viscosity delayed the onset as well as the duration of biosynthesis of prodigiosin. As an adaptation to viscous environment V. ruber increased metabolic flux through the pentose phosphate pathway and reduced synthesis of a secondary metabolite. In addition, V. ruber was able to modify the viscosity of its environment. PMID:22826705

  7. Viscosity of two-dimensional strongly coupled dusty plasma modified by a perpendicular magnetic field. (United States)

    Feng, Yan; Lin, Wei; Murillo, M S


    Transport properties of two-dimensional (2D) strongly coupled dusty plasmas have been investigated in detail, but never for viscosity with a strong perpendicular magnetic field; here, we examine this scenario using Langevin dynamics simulations of 2D liquids with a binary Yukawa interparticle interaction. The shear viscosity η of 2D liquid dusty plasma is estimated from the simulation data using the Green-Kubo relation, which is the integration of the shear stress autocorrelation function. It is found that, when a perpendicular magnetic field is applied, the shear viscosity of 2D liquid dusty plasma is modified substantially. When the magnetic field is increased, its viscosity increases at low temperatures, while at high temperatures its viscosity diminishes. It is determined that these different variational trends of η arise from the different behaviors of the kinetic and potential parts of the shear stress under external magnetic fields.

  8. Viscosity in Modified Gravity 

    Directory of Open Access Journals (Sweden)

    Iver Brevik


    Full Text Available A bulk viscosity is introduced in the formalism of modified gravity. It is shownthat, based on a natural scaling law for the viscosity, a simple solution can be found forquantities such as the Hubble parameter and the energy density. These solutions mayincorporate a viscosity-induced Big Rip singularity. By introducing a phase transition inthe cosmic fluid, the future singularity can nevertheless in principle be avoided. 

  9. Uniaxial Elongational viscosity of bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole


    The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational...... viscosity, of up to a factor of 7 times the Trouton limit of 3 times the zero-shear viscosity....

  10. Nucleophilic reactions of bromocyclopentane in the structure-H methane + bromocyclopentane mixed hydrate system at high pressures. (United States)

    Matsumoto, Yuuki; Katsuta, Yoshito; Kamo, Fumitaka; Bando, Tatsuya; Makino, Takashi; Sugahara, Takeshi; Ohgaki, Kazunari


    Thermodynamic stability boundary in the structure-H methane + bromocyclopentane mixed hydrate system was measured at pressures from 20 to 100 MPa. The thermodynamic stability boundary of the methane + bromocyclopentane mixed hydrate exhibits anomalous behavior under conditions at high pressures and high temperatures. This phenomenon is due to the elimination and substitution reactions of bromocyclopentane to cyclopentene and cyclopentanol, respectively. The nucleophilic reactions of bromocyclopentane are mainly advanced in the liquid bromocyclopentane-rich phases, while it is restrained when bromocyclopentane is enclathrated in hydrate cage.

  11. Morphological transformations of native petroleum emulsions. I. Viscosity studies. (United States)

    Evdokimov, Igor N; Efimov, Yaroslav O; Losev, Aleksandr P; Novikov, Mikhail A


    Emulsions of water in as-recovered native crude oils of diverse geographical origin evidently possess some common morphological features. At low volume fractions varphi of water, the viscosity behavior of emulsions is governed by the presence of flocculated clusters of water droplets, whereas characteristic tight gels, composed of visually monodisperse small droplets, are responsible for the viscosity anomaly at varphi approximately 0.4-0.5. Once formed, small-droplet gel domains apparently retain their structural integrity at higher varphi, incorporating/stabilizing new portions of water as larger-sized droplets. The maximum hold-up of disperse water evidently is the close-packing limit of varphi approximately 0.74. At higher water contents (up to varphi approximately 0.83), no inversion to O/W morphology takes place, but additional water emerges as a separate phase. The onset of stratified flow (W/O emulsion gel + free water) is the cause of the observed viscosity decrease, contrary to the conventional interpretation of the viscosity maximum as a reliable indicator of the emulsion inversion point.

  12. Passive non-linear microrheology for determining extensional viscosity (United States)

    Hsiao, Kai-Wen; Dinic, Jelena; Ren, Yi; Sharma, Vivek; Schroeder, Charles M.


    Extensional viscosity is a key property of complex fluids that greatly influences the non-equilibrium behavior and processing of polymer solutions, melts, and colloidal suspensions. In this work, we use microfluidics to determine steady extensional viscosity for polymer solutions by directly observing particle migration in planar extensional flow. Tracer particles are suspended in semi-dilute solutions of DNA and polyethylene oxide, and a Stokes trap is used to confine single particles in extensional flows of polymer solutions in a cross-slot device. Particles are observed to migrate in the direction transverse to flow due to normal stresses, and particle migration is tracked and quantified using a piezo-nanopositioning stage during the microfluidic flow experiment. Particle migration trajectories are then analyzed using a second-order fluid model that accurately predicts that migration arises due to normal stress differences. Using this analytical framework, extensional viscosities can be determined from particle migration experiments, and the results are in reasonable agreement with bulk rheological measurements of extensional viscosity based on a dripping-onto-substrate method. Overall, this work demonstrates that non-equilibrium properties of complex fluids can be determined by passive yet non-linear microrheology.

  13. Strongly correlated electrons at high pressure: an approach by inelastic X-Ray scattering; Electrons correles sous haute pression: une approche par diffusion inelastique des rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Rueff, J.P


    Inelastic X-ray scattering (IXS) and associated methods has turn out to be a powerful alternative for high-pressure physics. It is an all-photon technique fully compatible with high-pressure environments and applicable to a vast range of materials. Standard focalization of X-ray in the range of 100 microns is typical of the sample size in the pressure cell. Our main aim is to provide an overview of experimental results obtained by IXS under high pressure in 2 classes of materials which have been at the origin of the renewal of condensed matter physics: strongly correlated transition metal oxides and rare-earth compounds. Under pressure, d and f-electron materials show behaviors far more complex that what would be expected from a simplistic band picture of electron delocalization. These spectroscopic studies have revealed unusual phenomena in the electronic degrees of freedom, brought up by the increased density, the changes in the charge-carrier concentration, the over-lapping between orbitals, and hybridization under high pressure conditions. Particularly we discuss about pressure induced magnetic collapse and metal-insulator transitions in 3d compounds and valence fluctuations phenomena in 4f and 5f compounds. Thanks to its superior penetration depth, chemical selectivity and resonant enhancement, resonant inelastic X-ray scattering has appeared extremely well suited to high pressure physics in strongly correlated materials. (A.C.)

  14. Drop spreading with random viscosity

    CERN Document Server

    Xu, Feng


    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid's viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop's motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop's effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated v...

  15. Shear Viscosity from Lattice QCD

    CERN Document Server

    Mages, Simon W; Fodor, Zoltán; Schäfer, Andreas; Szabó, Kálmán


    Understanding of the transport properties of the the quark-gluon plasma is becoming increasingly important to describe current measurements at heavy ion collisions. This work reports on recent efforts to determine the shear viscosity h in the deconfined phase from lattice QCD. The main focus is on the integration of the Wilson flow in the analysis to get a better handle on the infrared behaviour of the spectral function which is relevant for transport. It is carried out at finite Wilson flow time, which eliminates the dependence on the lattice spacing. Eventually, a new continuum limit has to be carried out which sends the new regulator introduced by finite flow time to zero. Also the non-perturbative renormalization strategy applied for the energy momentum tensor is discussed. At the end some quenched results for temperatures up to 4 : 5 T c are presented

  16. Phase transition of solid bismuth under high pressure (United States)

    Chen, Hai-Yan; Xiang, Shi-Kai; Yan, Xiao-Zhen; Zheng, Li-Rong; Zhang, Yi; Liu, Sheng-Gang; Bi, Yan


    As a widely used pressure calibrator, the structural phase transitions of bismuth from phase I, to phase II, to phase III, and then to phase V with increasing pressure at 300 K have been widely confirmed. However, there are different structural versions for phase III, most of which are determined by x-ray diffraction (XRD) technology. Using x-ray absorption fine structure (XAFS) measurements combined with ab initio calculations, we show that the proposed incommensurate composite structure of bismuth of the three configurations is the best option. An abnormal continuous increase of the nearest-neighbor distance of phase III with elevated pressure is also observed. The electronic structure transformation from semimetal to metal is responsible for the complex behavior of structure transformation. Project supported by the National Natural Science Foundation of China (Grant Nos. 10904133, 11304294, 11274281, 11404006, and U1230201), the Development Foundation of China Academy of Engineering Physics (Grant Nos. 2015B0101004, 2013B0401062, and 2012A0101001), the Research Foundation of the Laboratory of Shock Wave and Detonation, China (Grant No. 9140C670201140C67282).

  17. The powerful high pressure tool for protein conformational studies

    Directory of Open Access Journals (Sweden)

    Marchal S.


    Full Text Available The pressure behavior of proteins may be summarized as a the pressure-induced disordering of their structures. This thermodynamic parameter has effects on proteins that are similar but not identical to those induced by temperature, the other thermodynamic parameter. Of particular importance are the intermolecular interactions that follow partial protein unfolding and that give rise to the formation of fibrils. Because some proteins do not form fibrils under pressure, these observations can be related to the shape of the stability diagram. Weak interactions which are differently affected by hydrostatic pressure or temperature play a determinant role in protein stability. Pressure acts on the 2º, 3º and 4º structures of proteins which are maintained by electrostatic and hydrophobic interactions and by hydrogen bonds. We present some typical examples of how pressure affects the tertiary structure of proteins (the case of prion proteins, induces unfolding (ataxin, is a convenient tool to study enzyme dissociation (enolase, and provides arguments to understand the role of the partial volume of an enzyme (butyrylcholinesterase. This approach may have important implications for the understanding of the basic mechanism of protein diseases and for the development of preventive and therapeutic measures.

  18. Influence of Oil Viscosity on Alkaline Flooding for Enhanced Heavy Oil Recovery

    Directory of Open Access Journals (Sweden)

    Yong Du


    Full Text Available Oil viscosity was studied as an important factor for alkaline flooding based on the mechanism of “water drops” flow. Alkaline flooding for two oil samples with different viscosities but similar acid numbers was compared. Besides, series flooding tests for the same oil sample were conducted at different temperatures and permeabilities. The results of flooding tests indicated that a high tertiary oil recovery could be achieved only in the low-permeability (approximately 500 mD sandpacks for the low-viscosity heavy oil (Zhuangxi, 390 mPa·s; however, the high-viscosity heavy oil (Chenzhuang, 3450 mPa·s performed well in both the low- and medium-permeability (approximately 1000 mD sandpacks. In addition, the results of flooding tests for the same oil at different temperatures also indicated that the oil viscosity put a similar effect on alkaline flooding. Therefore, oil with a high-viscosity is favorable for alkaline flooding. The microscopic flooding test indicated that the water drops produced during alkaline flooding for oils with different viscosities differed significantly in their sizes, which might influence the flow behaviors and therefore the sweep efficiencies of alkaline fluids. This study provides an evidence for the feasibility of the development of high-viscosity heavy oil using alkaline flooding.

  19. Intrinsic viscosity and rheological properties of natural and substituted guar gums in seawater. (United States)

    Wang, Shibin; He, Le; Guo, Jianchun; Zhao, Jinzhou; Tang, Hongbiao


    The intrinsic viscosity and rheological properties of guar gum (GG), hydroxypropyl guar (HPG) and carboxymethyl guar (CMG) in seawater and the effects of shear rate, concentration, temperature and pH on these properties were investigated. An intrinsic viscosity-increasing effect was observed with GG and HPG in seawater (SW) compared to deionized water (DW), whereas the intrinsic viscosity of CMG in seawater was much lower than that in DW due to a screening effect that reduced the repulsion between the polymer chains. Regardless of the functional groups, all sample solutions was well characterized by a modified Cross model that exhibited the transition from Newtonian to pseudoplastic in the low shear rate range at the concentrations of interest to industries, and their viscosity increased with the increase in their concentration but decreased with the increase in temperature. In contrast to nonionic GG or HPG, anionic CMG had a slightly decreased viscosity property in SW, exhibiting polyelectrolyte viscosity behavior. The α value in the zero-shear rate viscosity vs. concentration power-law equation for the samples gave the order of CMG>HPG>GG while the SW solution of CMG had the lowest viscous flow activation energy and exhibited a strong pH-dependent viscosity by a different shear rate. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Do Clustering Monoclonal Antibody Solutions Really Have a Concentration Dependence of Viscosity? (United States)

    Pathak, Jai A.; Sologuren, Rumi R.; Narwal, Rojaramani


    Protein solution rheology data in the biophysics literature have incompletely identified factors that govern hydrodynamics. Whereas spontaneous protein adsorption at the air/water (A/W) interface increases the apparent viscosity of surfactant-free globular protein solutions, it is demonstrated here that irreversible clusters also increase system viscosity in the zero shear limit. Solution rheology measured with double gap geometry in a stress-controlled rheometer on a surfactant-free Immunoglobulin solution demonstrated that both irreversible clusters and the A/W interface increased the apparent low shear rate viscosity. Interfacial shear rheology data showed that the A/W interface yields, i.e., shows solid-like behavior. The A/W interface contribution was smaller, yet nonnegligible, in double gap compared to cone-plate geometry. Apparent nonmonotonic composition dependence of viscosity at low shear rates due to irreversible (nonequilibrium) clusters was resolved by filtration to recover a monotonically increasing viscosity-concentration curve, as expected. Although smaller equilibrium clusters also existed, their size and effective volume fraction were unaffected by filtration, rendering their contribution to viscosity invariant. Surfactant-free antibody systems containing clusters have complex hydrodynamic response, reflecting distinct bulk and interface-adsorbed protein as well as irreversible cluster contributions. Literature models for solution viscosity lack the appropriate physics to describe the bulk shear viscosity of unstable surfactant-free antibody solutions. PMID:23442970