Sample records for temperature pressure processing

  1. Inactivation kinetics of Listeria monocytogenes by high-pressure processing: pressure and temperature variation. (United States)

    Doona, Christopher J; Feeherry, Florence E; Ross, Edward W; Kustin, Kenneth


    The enhanced quasi-chemical kinetics (EQCK) model is presented as a methodology to evaluate the nonlinear inactivation kinetics of baro-resistant Listeria monocytogenes in a surrogate protein food system by high-pressure processing (HPP) for various combinations of pressure (P= 207 to 414 MPa) and temperature (T= 20 to 50 °C). The EQCK model is based on ordinary differential equations derived from 6 "quasi-chemical reaction" steps. The EQCK model continuously fits the conventional stages of the microbial lifecycle: lag, growth, stationary phase, and death; and tailing. Depending on the conditions, the inactivation kinetics of L. monocytogenes by HPP show a lag, inactivation, and tailing. Accordingly, we developed a customized, 4-step subset version of the EQCK model sufficient to evaluate the HPP inactivation kinetics of L. monocytogenes and obtain values for the model parameters of lag (λ), inactivation rate (μ), rate constants (k), and "processing time" (tp). This latter parameter was developed uniquely to evaluate kinetics data showing tailing. Secondary models are developed by interrelating the fitting parameters with experimental parameters, and Monte Carlo simulations are used to evaluate parameter reproducibility. This 4-step model is also compared with the empirical Weibull and Polylog models. The success of the EQCK model (as its 4-step subset) for the HPP inactivation kinetics of baro-resistant L. monocytogenes showing tailing establishes several advantages of the EQCK modeling approach for investigating nonlinear microbial inactivation kinetics, and it has implications for determining mechanisms of bacterial spore inactivation by HPP. Results of this study will be useful to the many segments of the food processing industry (ready-to-eat meats, fresh produce, seafood, dairy) concerned with ensuring the safety of consumers from the health hazards of Listeria monocytogenes, particularly through the use of emerging food preservation technologies such as

  2. High pressure-temperature processing as an alternative for preserving basil

    NARCIS (Netherlands)

    Krebbers, B.; Matser, A.; Koets, M.; Bartels, P.; Berg, van den R.


    In this study the effect of sterilisation by high pressure (HP) on the quality of basil was compared to conventional processing techniques. By means of freezing, or blanching followed by drying, microbial reduction of spores was maximal one-log. Pulsed HP-temperature treatment yielded a reduction of

  3. Exploring the limits: A low-pressure, low-temperature Haber-Bosch process (United States)

    Vojvodic, Aleksandra; Medford, Andrew James; Studt, Felix; Abild-Pedersen, Frank; Khan, Tuhin Suvra; Bligaard, T.; Nørskov, J. K.


    The Haber-Bosch process for ammonia synthesis has been suggested to be the most important invention of the 20th century, and called the ‘Bellwether reaction in heterogeneous catalysis’. We examine the catalyst requirements for a new low-pressure, low-temperature synthesis process. We show that the absence of such a process for conventional transition metal catalysts can be understood as a consequence of a scaling relation between the activation energy for N2 dissociation and N adsorption energy found at the surface of these materials. A better catalyst cannot obey this scaling relation. We define the ideal scaling relation characterizing the most active catalyst possible, and show that it is theoretically possible to have a low pressure, low-temperature Haber-Bosch process. The challenge is to find new classes of catalyst materials with properties approaching the ideal, and we discuss the possibility that transition metal compounds have such properties.

  4. Effect of Process Temperature on Virus Inactivation during High Hydrostatic Pressure Processing of Contaminated Fruit Puree and Juice. (United States)

    Pan, Hao; Buenconsejo, Matthew; Reineke, Karl F; Shieh, Y Carol


    High pressure processing (HPP) can inactivate pathogens and retain fruit qualities. Elevated HPP pressure or time increases virus inactivation, but the effect of temperature is not consistently observed for norovirus and hepatitis A virus. In the present study, the effectiveness of HPP holding temperatures (puree using a 24-liter HPP system. The holding temperature was established by setting the HPP initial temperature via pretrials. All trials were able to arrive at the designated holding pressure and holding temperature simultaneously. MNV inactivation in juices was conducted at 300 MPa for 3 min with various holding temperatures (10 to 30°C). A regression equation was derived, Y = -0.08 × X + 2.6 log PFU, R2 = 0.96, where Y is the log reduction and X is the holding temperature. The equation was used to predict a 2.6-log reduction in juices at 0°C holding temperature and indicated that MNV inactivation was inversely proportional to temperature increase. MNV survival during HPP did not differ significantly in pomegranate and strawberry juices. However, MS2 coliphage inactivation was greater as the holding temperature increased (from 15 to 38°C) at 600 MPa for 3 min. The increased inactivation trend is presumably similar to that for hepatitis A virus, but the holding temperature was not correlated with the reduction of HPP-resistant MS2 in strawberry puree. When the HPP holding pressure was evaluated independently in strawberry puree, a 5-log reduction of MNV was predicted through regression analysis at the holding pressure of 424 MPa for 3 min at 20°C. These parameters should inactivate >5 log PFU of MNV in juices, based upon a greater inactivation in berry juice than in puree (1.16-versus 0.74-log reduction at 300 MPa). This research illustrates use of predictive inactivation and a feasible means for manipulating HPP parameters for effective virus inactivation in fruit juices and puree.

  5. Effects of holding pressure and process temperatures on the mechanical properties of moulded metallic parts

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Esteves, N.M.


    on the moulded metallic parts. Stainless steel 316L is used in the investigation to produce the specimen by metal injection moulding (MIM) and multiple analyses were carried out on samples produced with different combinations of holding pressure, mould temperature and melt temperature. Finally, the parts were...

  6. 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

  7. Survey of processes for high temperature-high pressure gas purification. [52 references

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, J.P.; Edwards, M.S.


    In order to ensure the optimum operating efficiency of a combined-cycle electric power generating system, it is necessary to provide gas treatment processes capable of operating at high temperatures (> 1000/sup 0/F) and high pressures (> 10 atm (absolute)). These systems will be required to condition the inlet stream to the gas turbine to suitable levels of gas purity (removal of particulate matter, sulfur, nitrogen, and alkali metal compounds) to be compatible with both environmental and machine constraints. A survey of the available and developmental processes for the removal of these various contaminant materials has been conducted. Based on the data obtained from a variety of sources, an analysis has been performed to evaluate the performance of a number of potential cleanup processes in view of the overall system needs. The results indicate that commercially available, reliable, and economically competitive hot-gas cleanup systems (for the removal of H/sub 2/S, particulate matter, alkali, and nitrogen compounds) capable of conditioning raw product gas to the levels required for turbine use will not be available for some time.

  8. Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures (United States)

    Fu, Qi; Socki, R. A.; Niles, Paul B.


    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

  9. Process for CO.sub.2 capture using zeolites from high pressure and moderate temperature gas streams (United States)

    Siriwardane, Ranjani V [Morgantown, WV; Stevens, Robert W [Morgantown, WV


    A method for separating CO.sub.2 from a gas stream comprised of CO.sub.2 and other gaseous constituents using a zeolite sorbent in a swing-adsorption process, producing a high temperature CO.sub.2 stream at a higher CO.sub.2 pressure than the input gas stream. The method utilizes CO.sub.2 desorption in a CO.sub.2 atmosphere and effectively integrates heat transfers for optimizes overall efficiency. H.sub.2O adsorption does not preclude effective operation of the sorbent. The cycle may be incorporated in an IGCC for efficient pre-combustion CO.sub.2 capture. A particular application operates on shifted syngas at a temperature exceeding C. and produces a dry CO.sub.2 stream at low temperature and high CO.sub.2 pressure, greatly reducing any compression energy requirements which may be subsequently required.

  10. High-pressure, high-temperature magic angle spinning nuclear magnetic resonance devices and processes for making and using same (United States)

    Hu, Jian Zhi; Hu, Mary Y.; Townsend, Mark R.; Lercher, Johannes A.; Peden, Charles H. F.


    Re-usable ceramic magic angle spinning (MAS) NMR rotors constructed of high-mechanic strength ceramics are detailed that include a sample compartment that maintains high pressures up to at least about 200 atmospheres (atm) and high temperatures up to about least about C. during operation. The rotor designs minimize pressure losses stemming from penetration over an extended period of time. The present invention makes possible a variety of in-situ high pressure, high temperature MAS NMR experiments not previously achieved in the prior art.

  11. Design and Construction of a Temperature and Pressure Data ...

    African Journals Online (AJOL)

    In this work, a temperature and pressure monitor is designed. The system takes in temperature and pressure readings from the temperature sensor (LM35) and the pressure sensor (MPX4115A) respectively. The temperature and pressure readings are processed by a microcontroller (PIC16F877A) and displayed on an LCD ...

  12. Development of a combined piezoresistive pressure and temperature sensor using a chemical protective coating for Kraft pulp digester process monitoring (United States)

    Mohammadi, Abdolreza R.; Bennington, Chad P. J.; Chiao, Mu


    We have developed an integrated piezoresistive pressure and temperature sensor for multiphase chemical reactors, primarily Kraft pulp digesters (pH 13.5, temperatures up to 175 °C, reaching a local maximum of 180 °C and pressures up to 2 MPa). The absolute piezoresistive pressure sensor consisted of a large square silicon diaphragm (1000 × 1000 µm2) and high resistance piezoresistors (10 000 Ω). A 4500 Ω buried piezoresistive wire was patterned on the silicon chip to form a piezoresistive temperature sensor which was used for pressure sensor compensation and temperature measurement. A 4 µm thick Parylene HT® coating, a chemically resistant epoxy and a silicone conformal coating were deposited to passivate the pressure sensor against the caustic environment in Kraft digesters. The sensors were characterized up to 2 MPa and 180 °C in an environment chamber. A maximum thermal error of ±0.72% full-scale output (FSO), an average sensitivity of 0.116 mV (V kPa)-1 and a power consumption of 0.3 mW were measured in the pressure sensor. The sensors' resistances were measured before and after test in a Kraft pulping cycle and showed no change in their values. SEM pictures and topographical surfaces were also analyzed before and after pulp liquor exposure and showed no observable changes.

  13. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg


    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive......, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established...

  14. Ultrahigh Temperature Capacitive Pressure Sensor (United States)

    Harsh, Kevin


    Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

  15. 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

  16. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.


    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  17. Carbon nanotube temperature and pressure sensors (United States)

    Ivanov, Ilia N.; Geohegan, David B.


    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  18. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.


    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  19. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.


    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  20. Carbon nanotube temperature and pressure sensors (United States)

    Ivanov, Ilia N; Geohegan, David Bruce


    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  1. Estimated vapor pressure for WTP process streams

    Energy Technology Data Exchange (ETDEWEB)

    Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

  2. Response Surface Optimization of Process Parameters and Fuzzy Analysis of Sensory Data of High Pressure-Temperature Treated Pineapple Puree. (United States)

    Chakraborty, Snehasis; Rao, Pavuluri Srinivasa; Mishra, Hari Niwas


    The high-pressure processing conditions were optimized for pineapple puree within the domain of 400-600 MPa, 40-60 °C, and 10-20 min using the response surface methodology (RSM). The target was to maximize the inactivation of polyphenoloxidase (PPO) along with a minimal loss in beneficial bromelain (BRM) activity, ascorbic acid (AA) content, antioxidant capacity, and color in the sample. The optimum condition was 600 MPa, 50 °C, and 13 min, having the highest desirability of 0.604, which resulted in 44% PPO and 47% BRM activities. However, 93% antioxidant activity and 85% AA were retained in optimized sample with a total color change (∆E*) value less than 2.5. A 10-fold reduction in PPO activity was obtained at 600 MPa/70 °C/20 min; however, the thermal degradation of nutrients was severe at this condition. Fuzzy mathematical approach confirmed that sensory acceptance of the optimized sample was close to the fresh sample; whereas, the thermally pasteurized sample (treated at 0.1 MPa, 95 °C for 12 min) had the least sensory score as compared to others. © 2015 Institute of Food Technologists®

  3. 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

  4. Ultrafine-grained magnesium–lithium alloy processed by high-pressure torsion: Low-temperature superplasticity and potential for hydroforming

    Energy Technology Data Exchange (ETDEWEB)

    Matsunoshita, Hirotaka [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Edalati, Kaveh, E-mail: [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Furui, Mitsuaki [Graduate School of Science and Engineering for Research, University of Toyama, Toyama 930-8555 (Japan); Horita, Zenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395 (Japan)


    A Mg–Li alloy with 8 wt% Li was processed by severe plastic deformation (SPD) through the process of high-pressure torsion (HPT) to achieve ultrafine grains with an average grain size of ~500 nm. Tensile testing with an initial strain rate of 10{sup −3} s{sup −1} showed that the alloy exhibited superplasticity at a temperature of 323 K or higher. Tensile testing in boiling water confirmed that the specimens were elongated to 350–480% at 373 K under the initial strain rates of 10{sup −3} s{sup −1} to {sup 1}0{sup −2} s{sup −1} with a strain rate sensitivity of ~0.3. The current study suggests that not only superplastic forming but also superplastic hydroforming should be feasible after the grain refinement using the HPT method.

  5. Ion Based High-Temperature Pressure Sensor

    National Research Council Canada - National Science Library

    Zdenek, Jeffrey S; Anthenien, Ralph A


    .... The environment encountered in such engines necessitates high temperature and durable (vibration resistant) devices. Traditional pressure sensors can be used, however thermal insulating materials must be used to protect the diaphragm...

  6. High Temperature Characterization of Ceramic Pressure Sensors

    National Research Council Canada - National Science Library

    Fonseca, Michael A; English, Jennifer M; Von Arx, Martin; Allen, Mark G


    This work reports functional wireless ceramic micromachined pressure sensors operating at 450 C, with demonstrated materials and readout capability indicating potential extension to temperatures in excess of 600 C...

  7. Low Temperature Atmospheric Pressure Plasma Sterilization Shower (United States)

    Gandhiraman, R. P.; Beeler, D.; Meyyappan, M.; Khare, B. N.


    Low-temperature atmospheric pressure plasma sterilization shower to address both forward and backward biological contamination issues is presented. The molecular effects of plasma exposure required to sterilize microorganisms is also analysed.

  8. Relationship between outdoor temperature and blood pressure. (United States)

    Halonen, Jaana I; Zanobetti, Antonella; Sparrow, David; Vokonas, Pantel S; Schwartz, Joel


    Cardiovascular mortality has been linked to changes in outdoor temperature. However, the mechanisms behind these effects are not well established. We aimed to study the effect of outdoor temperature on blood pressure, as increased blood pressure is a risk factor for cardiovascular death. The study population consisted of men aged 53-100 years living in the Boston area. We used a mixed effects model to estimate the effect of three temperature variables: ambient, apparent and dew point temperature (DPT), on repeated measures (every 3-5 years) of diastolic (DBP) and systolic blood pressure (SBP). Random intercepts for subjects and several possible confounders were used in the models, including black carbon and barometric pressure. We found modest associations between DBP and ambient and apparent temperature. In the basic models, DBP in association with a 5 °C decrease in 7-day moving averages of temperatures increased by 1.01% (95% CI -0.06% to 2.09%) and 1.55% (95% CI 0.61% to 2.49%) for ambient and apparent temperature, respectively. Excluding extreme temperatures strengthened these associations (2.13%, 95% CI 0.66% to 3.63%, and 1.65%, 95% CI 0.41% to 2.90%, for ambient and apparent temperature, respectively). Effect estimates for DPT were close to null. The effect of apparent temperature on SBP was similar (1.30% increase (95% CI 0.32% to 2.29%) for a 5 °C decrease in 7-day moving average). Cumulative exposure to decreasing ambient and apparent temperature may increase blood pressure. These findings suggest that an increase in blood pressure could be a mechanism behind cold-related, but not heat-related, cardiovascular mortality.

  9. Monolithic Composite “Pressure + Acceleration + Temperature + Infrared” Sensor Using a Versatile Single-Sided “SiN/Poly-Si/Al” Process-Module

    Directory of Open Access Journals (Sweden)

    Xinxin Li


    Full Text Available We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN/polysilicon (poly-Si/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions. The first “pressure + acceleration + temperature + infrared” (PATIR composite sensor with the chip size of 2.5 mm × 2.5 mm is demonstrated. Systematic theoretical design and analysis methods are developed. The diverse sensing components include a piezoresistive absolute-pressure sensor (up to 700 kPa, with a sensitivity of 49 mV/MPa under 3.3 V supplied voltage, a piezoresistive accelerometer (±10 g, with a sensitivity of 66 μV/g under 3.3 V and a −3 dB bandwidth of 780 Hz, a thermoelectric infrared detector (with a responsivity of 45 V/W and detectivity of 3.6 × 107 cm·Hz1/2/W and a thermistor (−25–120 °C. This design/fabrication module concept enables a low-cost monolithically-integrated “multifunctional-library” technique. It can be utilized as a customizable tool for versatile application-specific requirements, which is very useful for small-size, low-cost, large-scale sensing-network node developments.

  10. Borehole pressure and temperature measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Perales, K.L.


    This patent describes apparatus for continuously measuring fluctuating pressure and temperature of a downhole fluid in a borehole at a desired depth. It comprises a tube positioned within the borehole; a housing suspended in the borehole at the desired depth from the tube; a pressurized test fluid source at the surface for initially pressuring the flow path in the tube and a portion of the chamber in the housing; a valve for selectively isolating fluid communications between the tube and the pressurized test fluid source; a thermocouple line including two dissimilar metal conductors; a manifold at the surface for sealing the selected fluid within the flow path; a pressure measuring device at the surface and in fluid communication; and a temperature measuring device at the surface for receiving the thermocouple line.

  11. High pressure processing's potential to inactivate norovirus and other fooodborne viruses (United States)

    High pressure processing (HPP) can inactivate human norovirus. However, all viruses are not equally susceptible to HPP. Pressure treatment parameters such as required pressure levels, initial pressurization temperatures, and pressurization times substantially affect inactivation. How food matrix ...

  12. Experimental and Theoretical Studies on the Effect of Die Temperature on the Quality of the Products in High-Pressure Die-Casting Process

    Directory of Open Access Journals (Sweden)

    Mohammad Sadeghi


    Full Text Available Die temperature in high-pressure die casting of A380 alloy is optimized by experimental observation and numerical simulation. Ladder frame (one part of the new motor EF7 with a very complicated geometry was chosen as an experimental sample. Die temperature and melt temperature were examined to produce a sound part. Die temperatures at the initial step and the final filling positions were measured and the difference between these values was calculated. ProCAST software was used to simulate the fluid flow and solidification step of the part, and the results were verified by experimental measurements. It is shown that the proper die temperature for this alloy is above 200°C.

  13. Process Factors Influence on Cavity Pressure Behavior in Microinjection Moulding

    DEFF Research Database (Denmark)

    Griffiths, C. A.; Dimov, S. S.; Scholz, S.


    Process monitoring of microinjection moulding (mu IM) is of crucial importance when analysing the effect of different parameter settings on the process and then in assessing its quality. Quality factors related to cavity pressure can provide valuable information about the process dynamics and also...... about the filling behavior of different polymer melts. In this paper, a pressure sensor mounted inside a tool cavity was employed to analyse maximum cavity pressure, pressure increase rate during filling and pressure work. The influence of four mu IM parameters, melt temperature, mould temperature...

  14. 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.

  15. (ajst) on the pressure velocity and temperature

    African Journals Online (AJOL)

    ABSTRACT: In this paper, we examine the effects of viscosity on the blood pressure, velocity and temperature distributions in the arterial blood flow in the absence of outflows. The governing continuity, momentum and energy equations are solved analytically by method of characteristics. Using the wavefront expansions, ...

  16. Students' Investigations in Temperature and Pressure (United States)

    Brown, Patrick L.; Concannon, James; Hansert, Bernhard; Frederick, Ron; Frerichs, Glen


    Why does a balloon deflate when it is left in a cold car; or why does one have to pump up his or her bike tires in the spring after leaving them in the garage all winter? To answer these questions, students must understand the relationships among temperature, pressure, and volume of a gas. The purpose of the Predict, Share, Observe, and Explain…

  17. 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...

  18. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    temperatures and pressures. Aqueous potassium hydroxide immobilized electrolyte in porous SrTiO3 was used in those cells. Electrolysis cells with metal foam based gas diffusion electrodes and the immobilized electrolyte were successfully demonstrated at temperatures up to 250 °C and 40 bar. Different electro-catalysts...... were tested in order to reduce the oxygen and hydrogen overpotentials. Current densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without using expensive noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2...... against conventional technologies for hydrogen production, such as natural gas reforming, the production and investment costs have to be reduced. A reduction of the investment costs may be achieved by increasing the operational pressure and temperature of the electrolyzer, as this will result in: 1...

  19. 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.

  20. Pressure Effects on the Thermal De-NOx Process

    DEFF Research Database (Denmark)

    Kjærgaard, Karsten; Glarborg, Peter; Dam-Johansen, Kim


    The effect of pressure on the thermal de-NOx process has been investigated in flow reactor experiments. The experiments were performed at pressures from 1 to 10 bar and temperatures ranging from 925 to 1375 K. The inlet O-2 level was varied from 1000 ppm to 10%, while NH3 and NO were maintained...... effect of the pressure but also cause a slight decrease in the NO reduction potential. The results are consistent with recent atmospheric pressure experiments of thermal de-NOx covering a wide range of reactant partial pressures. Comparisons of the experimental data with the recent chemical kinetic model...... at 1000 and 500 ppm, respectively At the highest pressure, CO was added to shift the regime for NO reduction to lower temperatures. The results show that the pressure affects the location and the width of the temperature window for NO reduction. As the pressure is increased, both the lower and the higher...

  1. Effect of process parameters on cavity pressure in injection molding (United States)

    Wang, Quan; Zhen, Mengxiang; Wu, Zhenghuan; Cai, Yujun


    In this study, an experimental work is performed on the effect of injection molding parameters on the polymer pressure inside the mold cavity. Different process parameters of the injection molding are considered during the experimental work (packing pressure, packing time, injection pressure, mold temperature, and melt temperature). A set analyses are carried out by combining the process parameters based on the L16(45)Taguchi orthogonal design. The cavity pressure is measured with time by using Kistler pressure sensor at different injection molding cycles. The results show the packing pressure is significant factor of affecting the maximum of diverse spline cavity pressure. The results obtained specify well the developing of the cavity pressure inside the mold cavity during the injection molding cycles.

  2. Temperature Modelling of the Biomass Pretreatment Process

    DEFF Research Database (Denmark)

    Prunescu, Remus Mihail; Blanke, Mogens; Jensen, Jakob M.


    that captures the environmental temperature differences inside the reactor using distributed parameters. A Kalman filter is then added to account for any missing dynamics and the overall model is embedded into a temperature soft sensor. The operator of the plant will be able to observe the temperature in any......In a second generation biorefinery, the biomass pretreatment stage has an important contribution to the efficiency of the downstream processing units involved in biofuel production. Most of the pretreatment process occurs in a large pressurized thermal reactor that presents an irregular temperature...... distribution. Therefore, an accurate temperature model is critical for observing the biomass pretreatment. More than that, the biomass is also pushed with a constant horizontal speed along the reactor in order to ensure a continuous throughput. The goal of this paper is to derive a temperature model...

  3. Examining the microhardness evolution and thermal stability of an Al–Mg–Sc alloy processed by high-pressure torsion at a high temperature

    Directory of Open Access Journals (Sweden)

    Pedro Henrique R. Pereira


    Full Text Available An Al–3% Mg–0.2% Sc alloy was solution treated and processed through 10 turns of high-pressure torsion (HPT at 450 K. Afterwards, the HPT-processed alloy was annealed for 1 h at temperatures ranging from 423 to 773 K and its mechanical properties and microstructural evolution were examined using microhardness measurements and electron backscattered diffraction (EBSD analysis. The results demonstrate that HPT processing at an elevated temperature leads to a more uniform microhardness distribution and to an early saturation in the hardness values in the Al alloy compared with high-pressure torsion at room temperature. In addition, detailed EBSD analysis conducted on the HPT-processed samples immediately after annealing revealed that the Al–Mg–Sc alloy subjected to HPT processing at 450 K exhibits superior thermal stability by comparison with the same material subjected to HPT at 300 K. Keywords: Aluminium alloys, Hall–Petch relationship, Hardness, High-pressure torsion, Severe plastic deformation, Thermal stability

  4. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg


    for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen overpotentials. Current...... the operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2.3 A cm-2 were obtained....

  5. 3He melting pressure temperature scale

    DEFF Research Database (Denmark)

    Halperin, W.P.; Archie, C.N.; Richardson, R.C.


    The latent heat for solidification of **3He has been measured along the **3He melting curve between 23 and 1 mK. A temperature scale is established which depends only on measurements of heat, pressure and volume, and on the condition that the entropy of solid **3He approaches R ln 2 at high...... temperatures. The A feature of the melting curve which suggests itself as a thermometric fixed point is found to be T//A equals 2. 75 plus or minus 0. 11 mK. The agreement between this value and independent measurements of T//A, based on nuclear or electronic paramagnetism, Johnson noise thermometry...... or on properties of liquid **3He, is briefly discussed...

  6. Microwave Wire Interrogation Method Mapping Pressure under High Temperatures

    Directory of Open Access Journals (Sweden)

    Xiaoyong Chen


    Full Text Available It is widely accepted that wireless reading for in-situ mapping of pressure under high-temperature environments is the most feasible method, because it is not subject to frequent heterogeneous jointing failures and electrical conduction deteriorating, or even disappearing, under heat load. However, in this article, we successfully demonstrate an in-situ pressure sensor with wire interrogation for high-temperature applications. In this proof-of-concept study of the pressure sensor, we used a microwave resonator as a pressure-sensing component and a microwave transmission line as a pressure characteristic interrogation tunnel. In the sensor, the line and resonator are processed into a monolith, avoiding a heterogeneous jointing failure; further, microwave signal transmission does not depend on electrical conduction, and consequently, the sensor does not suffer from the heat load. We achieve pressure monitoring under 400 °C when employing the sensor simultaneously. Our sensor avoids restrictions that exist in wireless pressure interrogations, such as environmental noise and interference, signal leakage and security, low transfer efficiency, and so on.

  7. 40 CFR 1065.315 - Pressure, temperature, and dewpoint calibration. (United States)


    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Pressure, temperature, and dewpoint... Parameters and Ambient Conditions § 1065.315 Pressure, temperature, and dewpoint calibration. (a) Calibrate instruments for measuring pressure, temperature, and dewpoint upon initial installation. Follow the instrument...

  8. Glycerin Reformation in High Temperature and Pressure Water (United States)


    hygroscopic, while ethanol is renewable and non-toxic (94). Water has a detrimental effect on the reaction because soaps can be formed, which cause...Lavric, V. (2005) Delocalized organic pollutant destruction through a self-sustaining supercritical water oxidation process, Energy Conversion and...2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Glycerin Reformation in High Temperature and Pressure Water

  9. Sour pressure swing adsorption process

    Energy Technology Data Exchange (ETDEWEB)

    Bhadra, Shubhra Jyoti; Wright, Andrew David; Hufton, Jeffrey Raymond; Kloosterman, Jeffrey William; Amy, Fabrice; Weist, Jr., Edward Landis


    Methods and apparatuses for separating CO.sub.2 and sulfur-containing compounds from a synthesis gas obtained from gasification of a carbonaceous feedstock. The primary separating steps are performed using a sour pressure swing adsorption (SPSA) system, followed by an acid gas enrichment system and a sulfur removal unit. The SPSA system includes multiple pressure equalization steps and a rinse step using a rinse gas that is supplied from a source other than directly from one of the adsorber beds of the SPSA system.

  10. Aqueous Geochemistry at High Pressures and High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bass, Jay D. [Univ. of Illinois, Urbana-Champaign, IL (United States)


    This project is aimed at experimental characterization of the sound velocities, equations of state (EOS), and derived physical and chemical properties of aqueous solutions and carbon dioxide at extreme pressure and temperature conditions relevant to processes occurring in the interior of the Earth. Chemical transport, phase changes (including melting), fluid-solid reactions, and formation of magmatic liquids at convergent plat boundaries are a key motivation for this project. Research in this area has long been limited by the extreme experimental challenges and lack of data under the appropriate pressure-temperature (P-T) conditions. The vast majority of studies of aqueous geochemistry relevant to terrestrial problems of fluid-rock interactions have been conducted at 0.3 GPa or less, and the widely used Helgeson-Kirkham-Flowers equation of state for aqueous species is applicable only at ~ < 0.5 GPa. These limits are unfortunate because fluid flow and reactions plays a central role in many deeper environments. Recent efforts including our own, have resulted in new experimental techniques that now make it possible to investigate properties of homogeneous and heterogeneous equilibria involving aqueous species and minerals over a much broader range of pressure and temperature appropriate for deep crustal and upper mantle processes involving water-rich fluids. We carried out 1) Brillouin scattering measurements of the equations of state and molar volume of water and carbon dioxide to over 10 GPa and 870K using precise resistance heating of samples under pressure in the diamond anvil cell, and 2) the phase diagrams of the water and CO2, and 3) Exploring new experimental approaches, including CO2 laser heating of samples in a diamond cell, to measurements of sound velocities, EOS, and phase relations by Brillouin scattering to far greater pressures and temperatures.

  11. Synthesis of a new high-pressure and high-temperature iron oxide, Fe4O5, a plausible key player in deep subduction processes (United States)

    Lavina, B.; Dera, P. K.; Kim, E.; Dobrzhinetskaya, L.; Meng, Y.; Downs, R. T.; Weck, P. F.; Sutton, S. R.; Zhao, Y.; Alp, E.


    Iron oxides have broad geophysical and geochemical relevance due to their abundance, electronic properties and role in redox equilibria. While investigating the stability and decomposition products of siderite (FeCO3) at conditions of the Earth's mantle we obtained, at 10 GPa and about 1800 K, a single crystal of unknown phase. High pressure and temperatures were achieved using a laser heated diamond anvil cell. Diffraction data were obtained using highly focused synchrotron x-rays. Structural solution and refinement of the single crystal diffraction pattern indicate that the phase is a new compound with formula Fe4O5 [1]. The phase has orthorhombic symmetry where iron is 6-coordinated in layers of trigonal prisms and edge-sharing octahedra. First-principle calculations show that Fe4O5 is stable at high pressure with respect to its possible breakdown products (FeO and Fe3O4 in the cubic and orthorhombic structures). We performed several HP-HT syntheses starting from mixtures of pure Fe+Fe3O4 and Fe+Fe2O3 in appropriate proportions. Fe4O5 was synthesized in the range 10-20 GPa readily upon heating at temperature in the range 1500-2500 K. Upon decompression and further heating we observed the decomposition of Fe4O5 at ~ 5GPa and 1800K, to wüstite and magnetite; whereas cold decompression shows that orthorhombic Fe4O5 is a phase retrievable to ambient conditions. The new Fe-O compound has a broad fundamental and applicative significance, spanning planetary science, physics, chemistry and materials science. Also, the new iron oxide is a plausible phase of deep Earth, considering that it is rather reduced and taking into account the high heterogeneity of the upper mantle. Many peridotite from deep (>200-300km) subduction zones contain olivine and garnet rich in Fe3O4 lamellae exsolution which attest to the decompression of precursor phases that had formed at profound depths preceding mantle upwelling[2]. Microdiamonds from UHP gneisses also contain abundant Fex

  12. Pressure sensor based on distributed temperature sensing

    NARCIS (Netherlands)

    van Baar, J.J.J.; Wiegerink, Remco J.; Berenschot, Johan W.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt


    A differential pressure sensor has been realized with thermal readout. The thermal readout allows simultaneous measurement of the membrane deflection due to a pressure difference and measurement of the absolute pressure by operating the structure as a Pirani pressure sensor. The measuring of the

  13. High pressure grinding savages process costs

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, N.


    The Polycom process is a new method of ore processing based on pressure comminution, which has been successfully applied to cement clinker, limestone, coal, and other minerals. The process, in which grinding rolls expose a batch or bed of material to pressure that is sufficiently high to break the material, is described, together with its industrial applications and the advantages of the process over the conventional rod and ball mill combination. 7 figs.

  14. High Accuracy, Miniature Pressure Sensor for Very High Temperatures Project (United States)

    National Aeronautics and Space Administration — SiWave proposes to develop a compact, low-cost MEMS-based pressure sensor for very high temperatures and low pressures in hypersonic wind tunnels. Most currently...

  15. Pressure Controlled Heat Pipe for Precise Temperature Control Project (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research project will develop Pressure Controlled Heat Pipes (PCHPs) for precise temperature control (milli-Kelvin level). Several...

  16. 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

  17. Effect of pressure applied during casting on temperatures beneath casts. (United States)

    Deignan, Brian J; Iaquinto, Joseph M; Eskildsen, Scott M; Woodcock, Cassandra A; Owen, John R; Wayne, Jennifer S; Kuester, Victoria G


    Burns and pressure sores are common injuries during cast application. Various factors such as water temperature, padding, and cast material layers may play a role in these injuries; however, the effect of cast molding on temperatures and pressures has not been investigated. This raises the following questions, does the application of molding during cast application: (1) alter skin level temperatures in a variety of cast materials? and (2) risk inducing either thermal injury or pressure necrosis? An upper extremity model was created to measure pressure and temperature underneath casting materials. Cast padding, water bath temperature, and cast thickness were standardized. A 3-point mold was simulated using 3 casting materials-Fiberglass only, Plaster Only splint, and Plaster splint overwrapped with Fiberglass-while pressure and temperature were recorded. : Pressure application led to a statistically significant (PFiberglass combination reached an average peak temperature of 47.9°C, which was maintained for up to 6 minutes. Neither Fiberglass nor Plaster Only reached peak temperatures of this magnitude (average of 42.7 and 43.6°C, respectively). Peak (369 mm Hg) and highest residual (21 mm Hg) pressures were below harmful levels. Pressure application during casting is a risk factor for burn injuries. Care should be taken when molding a plaster splint overwrapped in fiberglass by waiting until the plaster has fully cooled. Combined with other known risk factors, the pressure from molding a cast could increase the likelihood of causing cutaneous burns.

  18. Pirani pressure sensor with distributed temperature measurement

    NARCIS (Netherlands)

    de Jong, B.R.; Bula, W.P.; Zalewski, D.R.; van Baar, J.J.J.; Wiegerink, Remco J.


    Surface micro-machined distributed Pirani pressure gauges, with designed heater-to-heat sink distances (gap-heights) of 0.35 μm and 1.10 μm, are successfully fabricated, modeled and characterized. Measurements and model response correspond within 5% of the measured value in a pressure range of 10 to

  19. Temperature effects in photodynamic processes (United States)

    Hovhannisyan, Vladimir A.; Avetisyan, Hasmik A.; Mathevosyan, Margarita B.; Elbakyan, Egishe G.


    Photodynamic activity of several dyes on Drosophila melanogaster at different temperatures (15-35°C) inside of test-tubes was investigated. Both phototoxic sensitizers (chlorin e6, methylene blue, etc. -group A) and non active compounds (hemoglobin, brilliant green, pyronine, etc.-group B) were used. Dyes of 10-5-10-3 M concentration were added to the food for drosophila 24 hours before irradiation. Solar radiation, narrow-band halogen lamps, LEDs and laser were used as a photo-stimulator. Irradiation parameters: I dyes in the control test-tubes at all doses of irradiation and temperatures applied percentage of survived insects was approximately 100%. In the darkness with the use of all dyes observations also indicated no damage to the insects. At the temperatures up to 25°C when using dyes of group B insects were not affected at all, while with the dyes of group A findings showed dose-dependent insect mortality. At high temperatures (30-35°C) when using group B dyes flies were losing their mobility and in the case of group A dyes the drosophila"s survival value sharply dropped. Combination of dyes from A group with some dyes from B group leads to the partial disappearance of photodynamic effect. This, probably, is concerned with the toxic photoproduct suppression by the inactive dye. Experimental model of drosophila allows to investigate photosensitization impact within wide temperature range, to find out the processes, when using combination of dyes, as well as to study photodynamic effect on reproductive functions of insects.

  20. Effects of pressure and temperature on gate valve unwedging

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, P.S.; Harrison, D.H.; Hayes, P.W.; Simons, J.W.; Walker, T.A.


    The stem thrust required to unwedge a gate valve is influenced by the pressure and temperature when the valve is closed and by the changes in these conditions between closure and opening. {open_quotes}Pressure locking{close_quotes} and {open_quotes}thermal binding{close_quotes} refer to situations where pressure and temperature effects cause the unwedging load to be much higher than normal. A model of these phenomena has been developed. Wedging (closure) is modeled as developing an {open_quotes}interference{close_quotes} between the disk and its seat rings in the valve. The effects of pressure and temperature are analyzed to determine the change in this disk-to-seat {open_quotes}interference{close_quotes}. Flexibilities, of the disk, body, stem and yoke strongly influence the unwedging thrust. Calculations and limited comparisons to data have been performed for a range of valve designs and scenarios. Pressure changes can increase the unwedging load when there is either a uniform pressure decrease, or a situation where the bonnet pressure exceeds the pressures in the adjacent piping. Temperature changes can increase the unwedging load when: (1) valve closure at elevated system temperature produces a delayed stem expansion, (2) a temperature increase after closure produces a bonnet pressure increase, or (3) a temperature change after closure produces an increase in the disk-to-seat {open_quotes}interference{close_quotes} or disk-to-seat friction.

  1. 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.

  2. Optical Pressure-Temperature Sensor for a Combustion Chamber (United States)

    Wiley, John; Korman, Valentin; Gregory, Don


    A compact sensor for measuring temperature and pressure in a combusti on chamber has been proposed. The proposed sensor would include two optically birefringent, transmissive crystalline wedges: one of sapph ire (Al2O3) and one of magnesium oxide (MgO), the optical properties of both of which vary with temperature and pressure. The wedges wou ld be separated by a vapor-deposited thin-film transducer, which wou ld be primarily temperaturesensitive (in contradistinction to pressur e- sensitive) when attached to a crystalline substrate. The sensor w ould be housed in a rugged probe to survive the extreme temperatures and pressures in a combustion chamber.

  3. Modern gas-based temperature and pressure measurements

    CERN Document Server

    Pavese, Franco


    This 2nd edition volume of Modern Gas-Based Temperature and Pressure Measurements follows the first publication in 1992. It collects a much larger set of information, reference data, and bibliography in temperature and pressure metrology of gaseous substances, including the physical-chemical issues related to gaseous substances. The book provides solutions to practical applications where gases are used in different thermodynamic conditions. Modern Gas-Based Temperature and Pressure Measurements, 2nd edition is the only comprehensive survey of methods for pressure measurement in gaseous media used in the medium-to-low pressure range closely connected with thermometry. It assembles current information on thermometry and manometry that involve the use of gaseous substances which are likely to be valid methods for the future. As such, it is an important resource for the researcher. This edition is updated through the very latest scientific and technical developments of gas-based temperature and pressure measurem...

  4. Curing Pressure Influence of Out-of-Autoclave Processing on Structural Composites for Commercial Aviation

    National Research Council Canada - National Science Library

    Drakonakis, Vasileios M; Seferis, James C; Doumanidis, Charalambos C


    ...) composite structures used in aviation. During the autoclave process, consolidation of prepreg laminas through simultaneous elevated pressure and temperature results in a uniform high-end material system...

  5. Capacitive pressure sensor in post-processing on LTCC substrates

    NARCIS (Netherlands)

    Meijerink, M.G.H.; Nieuwkoop, E.; Veninga, E.P.; Meuwissen, M.H.H.; Tijdink, M.W.W.J.


    A capacitive pressure sensor was realized by means of a post-processing step on a low temperature co-fired ceramics (LTCC) substrate. The new sensor fabrication technology allows for integration of the sensor with interface circuitry and possibly also wireless transmission circuits on LTCC

  6. Differences in pressure and temperature transitions of proteins and polymer gels

    Directory of Open Access Journals (Sweden)

    Kunugi S.


    Full Text Available Pressure-driven and temperature-driven transitions of two thermoresponsive polymers, poly(N-isopropylacrylamide (pNIPAM and poly(N-vinylisobutyramide (pNVIBA, in both a soluble linear polymer form and a cross-linked hydro-gel form, were examined by a dynamic light-scattering method and direct microscopic observation, respectively. Their behavior was compared with that of protein systems. Changes in some characteristic parameters in the time-intensity correlation functions of dynamic light-scattering measurement of aqueous solutions of pNIPAM at various pressures and temperatures showed no essential differences during temperature and pressure scanning and, as a whole, the motions of polymers in aqueous solutions were similar in two types of transitions until chain shrinkage occurred. The gels (cross-linked polymer gels prepared from the thermoresponsive polymers also showed similar volume transitions responding to the pressure and temperature increase. In temperature transitions, however, gels showed drastic volume shrinkage with loss of transparency, while pressure-induced transition showed a slow recovery of transparency while keeping the size, after first transient drastic volume shrinkage with loss of transparency. At a temperature slightly higher than the transition under atmospheric temperature, so-called reentry of the volume change and recovery of the transparency were observed during the pressure-increasing process, which implies much smaller aggregation or non-aggregated collapsed polymer chains in the gel at higher pressures, indicating a certain mechanistic difference of the dehydration processes induced by temperature and pressure.

  7. Imbedded fiber optic pressure and temperature sensors enable cure monitoring of pultruded composite materials (United States)

    Cable, David


    The application of fiberoptic multifunction sensing system for the measurement of temperature and pressure during the curing of fiberglass/epoxy composite structure is described. The system employs interferometric principles to measure temperature, pressure, and refractive index of liquids as well as other physical parameters. Fiberoptic pressure and temperature sensors have been employed in monitoring composites pultrusion and molding. The system is ideally suited for monitoring a variety of composite curing processes because of the sensor's microminiature size, tolerance of moderately high temperatures, non-metallic construction, and inherent immunity to electromagnetic and radio frequency signals.

  8. In-Situ Rolling Element Bearing Temperature and/or Pressure Measurement

    National Research Council Canada - National Science Library

    Nickel, David


    ... attitude-control wheels. Thin-film deposition and patterning processes have been formulated for the production of thin-film resistive sensors for in-situ measurement of pressure and temperature transients in lubricated contacts...

  9. Compliant Foil Journal Bearing Performance at Alternate Pressures and Temperatures (United States)

    Bruckner, Robert J.; Puleo, Bernadette J.


    An experimental test program has been conducted to determine the highly loaded performance of current generation gas foil bearings at alternate pressures and temperatures. Typically foil bearing performance has been reported at temperatures relevant to turbomachinery applications but only at an ambient pressure of one atmosphere. This dearth of data at alternate pressures has motivated the current test program. Two facilities were used in the test program, the ambient pressure rig and the high pressure rig. The test program utilized a 35 mm diameter by 27 mm long foil journal bearing having an uncoated Inconel X-750 top foil running against a shaft with a PS304 coated journal. Load capacity tests were conducted at 3, 6, 9, 12, 15, 18, and 21 krpm at temperatures from 25 to 500 C and at pressures from 0.1 to 2.5 atmospheres. Results show an increase in load capacity with increased ambient pressure and a reduction in load capacity with increased ambient temperature. Below one-half atmosphere of ambient pressure a dramatic loss of load capacity is experienced. Additional lightly loaded foil bearing performance in nitrogen at 25 C and up to 48 atmospheres of ambient pressure has also been reported. In the lightly loaded region of operation the power loss increases for increasing pressure at a fixed load. Knowledge of foil bearing performance at operating conditions found within potential machine applications will reduce program development risk of future foil bearing supported turbomachines.

  10. Conditional Sampling of Oceanic Temperature and Pressure. (United States)


    for surface waves will decrease with increased depth. This bottom pressure attenuation is plotted in figure 5 for a 200m shelf and a 5000m open ocean...77778 into the program counter and halts the CPU. Then a run pulse, which starts the CPU, is issued. Also on the CPU card are logic gates for the

  11. 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.

  12. 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.

  13. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors. (United States)

    Poeggel, Sven; Duraibabu, Dineshbabu; Kalli, Kyriacos; Leen, Gabriel; Dooly, Gerard; Lewis, Elfed; Kelly, Jimmy; Munroe, Maria


    This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS). The optical sensor of this research is based on an extrinsic Fabry-Perot interferometer (EFPI) with integrated fibre Bragg grating (FBG) for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF) acid and femtosecond (FS) laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of sp = 2-10 nm/kPa and a resolution of better than ΔP = 10 Pa protect (0.1 cm H2O). A static pressure test in 38 cm H2O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H2O) in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by k = 10.7 pm/K, which results in a temperature resolution of better than ΔT = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

  14. High temperature gas cleaning for pressurized gasification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Alden, H.; Hagstroem, P.; Hallgren, A.; Waldheim, L. [TPS Termiska Processer AB, Nykoeping (Sweden)


    The purpose of the project was to build an apparatus to study pressurized, high temperature gas cleaning of raw gasification gas generated from biomass. A flexible and easy to operate pressurized apparatus was designed and installed for the investigations in high temperature gas cleaning by means of thermal, catalytic or chemical procedures. A semi continuos fuel feeding concept, at a maximum rate of 700 g/h, allowed a very constant formation of a gas product at 700 deg C. The gas product was subsequently introduced into a fixed bed secondary reactor where the actual gas cleanup or reformation was fulfilled. The installation work was divided into four work periods and apart from a few delays the work was carried out according to the time plan. During the first work period (January - June 1994) the technical design, drawings etc. of the reactor and additional parts were completed. All material for the construction was ordered and the installation work was started. The second work period (July - December 1994) was dedicated to the construction and the installation of the different components. Initial tests with the electrical heating elements, control system and gas supply were assigned to the third work period (January - June 1995). After the commissioning and the resulting modifications, initial pyrolysis and tar decomposition experiments were performed. During the fourth and final work period, (June - December 1995) encouraging results from first tests allowed the experimental part of the project work to commence, however in a slightly reduced program. The experimental part of the project work comparatively studied tar decomposition as a function of the process conditions as well as of the choice of catalyst. Two different catalysts, dolomite and a commercial Ni-based catalyst, were evaluated in the unit. Their tar cracking ability in the pressure interval 1 - 20 bar and at cracker bed temperatures between 800 - 900 deg C was compared. Long term tests to study

  15. Food processing by high hydrostatic pressure. (United States)

    Yamamoto, Kazutaka


    High hydrostatic pressure (HHP) process, as a nonthermal process, can be used to inactivate microbes while minimizing chemical reactions in food. In this regard, a HHP level of 100 MPa (986.9 atm/1019.7 kgf/cm2) and more is applied to food. Conventional thermal process damages food components relating color, flavor, and nutrition via enhanced chemical reactions. However, HHP process minimizes the damages and inactivates microbes toward processing high quality safe foods. The first commercial HHP-processed foods were launched in 1990 as fruit products such as jams, and then some other products have been commercialized: retort rice products (enhanced water impregnation), cooked hams and sausages (shelf life extension), soy sauce with minimized salt (short-time fermentation owing to enhanced enzymatic reactions), and beverages (shelf life extension). The characteristics of HHP food processing are reviewed from viewpoints of nonthermal process, history, research and development, physical and biochemical changes, and processing equipment.

  16. Design and Evaluation of a Pressure and Temperature Monitoring System for Pressure Ulcer Prevention

    Directory of Open Access Journals (Sweden)

    Farve Daneshvar Fard


    Full Text Available Introduction Pressure ulcers are tissue damages resulting from blood flow restriction, which occurs when the tissue is exposed to high pressure for a long period of time. These painful sores are common in patients and elderly, who spend extended periods of time in bed or wheelchair. In this study, a continuous pressure and temperature monitoring system was developed for pressure ulcer prevention. Materials and Methods The monitoring system consists of 64 pressure and 64 temperature sensors on a 40×50 cm2 sheet. Pressure and temperature data and the corresponding maps were displayed on a computer in real-time. Risk assessment could be performed by monitoring and recording absolute pressure and temperature values, as well as deviations over time. Furthermore, a posture detection procedure was proposed for sitting posture identification. Information about the patient’s movement history may help caregivers make informed decisions about the patient’s repositioning and ulcer prevention strategies. Results Steady temporal behaviour of the designed system and repeatability of the measurements were evaluated using several particular tests. The results illustrated that the system could be utilized for continuous monitoring of interface pressure and temperature for pressure ulcer prevention. Furthermore, the proposed method for detecting sitting posture was verified using a statistical analysis. Conclusion A continuous time pressure and temperature monitoring system was presented in this study. This system may be suited for pressure ulcer prevention given its feasibility for simultaneous monitoring of pressure and temperature and alarming options. Furthermore, a method for detecting different sitting postures was proposed and verified. Pressure ulcers in wheelchair-bound patients may be prevented using this sitting posture detection method.

  17. Research at Very High Pressures and High Temperatures (United States)

    Bundy, Francis P.


    Reviews research and apparatus utilized in the study of the states and characteristics of materials at very high temperatures and pressures. Includes three examples of the research being conducted. (SL)

  18. Solar occultation sounding of pressure and temperature using narrowband radiometers. (United States)

    Park, J H; Russell Iii, J M; Smith, M A


    A technique for simultaneously retrieving pressure and temperature profiles using satellite-based narrow-band radiometer measurements of absorption in the CO(2) 4.3-microm band is described. Pressure and temperature profiles for earth's upper atmosphere on a global scale can be obtained with errors <3% and 3 K, respectively. The p - T information can be used not only for improving the accuracy of inverted gas concentrations in the same absorption experiment but also for investigating the upper atmosphere circulation.

  19. Diverse signatures of deformation, pressure-temperature and ...

    Indian Academy of Sciences (India)

    Integration of data from pressure-temperature sensors suggest cooling at two pressures, 6 and 5 kbar. The generation of two types of granitoids from metapelites is interpreted to be due to intersection with solidus curves for pelitic and graywacke-like compositions, constrained by recent experiments, at 6 and 5 kbar. The first ...

  20. Innovations in plantar pressure and foot temperature measurements in diabetes

    NARCIS (Netherlands)

    Bus, S. A.


    Plantar pressure and temperature measurements in the diabetic foot primarily contribute to identifying abnormal values that increase risk for foot ulceration, and they are becoming increasingly more integrated in clinical practice and daily life of the patient. While plantar pressure measurements

  1. Digital pressure transducer for use at high temperatures (United States)

    Karplus, H.H.B.

    A digital pressure sensor for measuring fluid pressures at relatively high temperatures includes an electrically conducting fiber coupled to the fluid by a force disc that causes tension in the fiber to be a function of fluid pressure. The tension causes changes in the mechanical resonant frequency of the fiber, which is caused to vibrate in a magnetic field to produce an electrical signal from a positive-feedback amplifier at the resonant frequency. A count of this frequency provides a measure of the fluid 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. Pressure-Temperature History of Shock-Induced Melt Veins (United States)

    Decarli, P. S.; Sharp, T. G.; Xie, Z.; Aramovich, C.


    Shock-induced melt veins that occur in chondrites commonly contain metastable high-pressure phases such as (Mg,Fe)SiO3-perovskite, akimotoite, ringwoodite, and majorite, that crystallized from the melt at high pressure. The metastable high-pressure minerals invert rapidly to stable low-pressure phases if they remain at high temperatures after the pressure is released. Although shock compression mechanisms permit rapid heating of the vein volume, adiabatic cooling on decompression is negligible because of the relative incompressibility of the material in the vein. The presence of metastable mantle minerals in a vein thus implies that the vein was quenched via thermal conduction to adjacent cooler material at high pressure. The quenching time of the vein can be determined from ordinary heat flow calculations (Langenhorst and Poirier, 2000), given knowledge of the vein dimensions and the temperatures at the time of vein formation in both the vein and the surrounding material. We have calculated a synthetic Hugoniot for the Tenham L6 chondrite to estimate bulk post-shock and shock temperatures as a function of shock pressure. Assuming a superliquidus temperature of 2500°C for the melt vein, we use a simple thermal model to investigate then thermal histories of melt veins during shock. The variation in crystallization assemblages within melt veins can be explained in terms of variable cooling rates. Survival of (Mg,Fe)SiO3-perovskite in Tenham (Tomioka and Fugino, 1997) requires that melt veins cooled to below 565°C before pressure release, which further constrains shock pressure, duration of the pressure pulse and cooling histories.

  4. Optimization of a Pressure-Treating Process

    Directory of Open Access Journals (Sweden)

    Josean Velez


    Full Text Available A company that pressure-treats wood wants to minimize its annual cost without using more than 250 days of operation per year. In addition, they want to find the corresponding value of time, batches and cost for each category. We develop an expression in terms of boards per batch to model the total cost of the treatment process. We then take the derivative and use Newton's Method to find the number of boards per batch that minimizes total cost.

  5. Changes in barometric pressure and ambient temperature influence osteoarthritis pain. (United States)

    McAlindon, Tim; Formica, Margaret; Schmid, Christopher H; Fletcher, Jeremiah


    Individuals with osteoarthritis often assert that change in the weather influences their pain, but the evidence is inconclusive. Our objective was to determine if short-term weather parameters influence knee osteoarthritis pain. We performed a longitudinal analysis of pain reports from a 3-month clinical trial among individuals with knee osteoarthritis dispersed across the United States. Daily values for temperature, barometric pressure, dew point, precipitation, and relative humidity were obtained from the weather station closest to each participant. We used a longitudinal mixed-model random effects analysis with a first-order autoregressive error structure to test for associations while accounting for within-patient correlation. The study included 200 participants with knee osteoarthritis. Their mean age was 60 years (standard deviation [SD] 9.4), 64% were female, and 10.5% were African American or Hispanic. They had a mean body mass index of 32.5 kg/m2 (SD 8.4) and a baseline WOMAC pain score of 9.0 (SD 3.4). There were consistent associations of pressure change and ambient temperature with pain severity (change in barometric pressure, coefficient = 1.14, P = .02, ambient temperature = -0.01, P = .004; adjusted mutually and for age, gender, body mass index, nonsteroidal anti-inflammatory drug use, opiate use, and prior pain score). Interaction terms between change in barometric pressure and ambient temperature had no influence in the models. Changes in barometric pressure and ambient temperature are independently associated with osteoarthritis knee pain severity.

  6. Asphaltene laboratory assessment of a heavy onshore reservoir during pressure, temperature and composition variations to predict asphaltene onset pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, Peyman; Ahmadi, Yaser [Islamic Azad University, Tehran (Iran, Islamic Republic of); Kharrat, Riyaz [Petroleum University of Technology, Tehran (Iran, Islamic Republic of); Mahdavi, Sedigheh; James, Lesley [Memorial University of Newfoundland, Saint John' s (Canada)


    An Iranian heavy oil reservoir recently encountered challenges in oil production rate, and further investigation has proven that asphaltene precipitation was the root cause of this problem. In addition, CO{sub 2} gas injection could be an appropriate remedy to enhance the production of heavy crudes. In this study, high pressure-high temperature asphaltene precipitation experiments were performed at different temperatures and pressures to investigate the asphaltene phase behavior during the natural depletion process and CO{sub 2} gas injection. Compositional modeling of experimental data predicted onset points at different temperatures which determine the zone of maximum probability of asphaltene precipitation for the studied heavy oil reservoir. Also, the effect of CO{sub 2} gas injection was investigated as a function of CO{sub 2} concentration and pressure. It was found that a CO{sub 2}-oil ratio of 40% is the optimum for limiting precipitation to have the least formation damage and surface instrument contamination.

  7. Pressure and temperature effects in homopolymer blends and diblock copolymers

    DEFF Research Database (Denmark)

    Frielinghaus, H.; Schwahn, D.; Mortensen, K.


    fluctuations. Phase boundaries, the Flory-Huggins interaction parameter and the Ginzburg number were obtained. The packing of the molecules changes with pressure. Therefore, the degree of thermal fluctuation as a function of packing and temperature was studied. While in polymer blends packing leads, in some......Thermal composition fluctuations in a homogeneous binary polymer blend and in a diblock copolymer were measured by small-angle neutron scattering as a function of temperature and pressure. The experimental data were analyzed with theoretical expressions, including the important effect of thermal...... of the 'mean-field' approximation and the three-dimensional Ising model. The phase boundaries in blends increase with pressure, while the phase boundary of the studied block copolymer shows an unusual shape: with increasing pressure it first decreases and then increases. Its origin is an increase...

  8. Extreme Environment Silicon Carbide Hybrid Temperature & Pressure Optical Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Nabeel Riza


    This final report contains the main results from a 3-year program to further investigate the merits of SiC-based hybrid sensor designs for extreme environment measurements in gas turbines. The study is divided in three parts. Part 1 studies the material properties of SiC such as temporal response, refractive index change with temperature, and material thermal response reversibility. Sensor data from a combustion rig-test using this SiC sensor technology is analyzed and a robust distributed sensor network design is proposed. Part 2 of the study focuses on introducing redundancy in the sensor signal processing to provide improved temperature measurement robustness. In this regard, two distinct measurement methods emerge. A first method uses laser wavelength sensitivity of the SiC refractive index behavior and a second method that engages the Black-Body (BB) radiation of the SiC package. Part 3 of the program investigates a new way to measure pressure via a distance measurement technique that applies to hot objects including corrosive fluids.

  9. A harsh environment wireless pressure sensing solution utilizing high temperature electronics. (United States)

    Yang, Jie


    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines.

  10. A Harsh Environment Wireless Pressure Sensing Solution Utilizing High Temperature Electronics (United States)

    Yang, Jie


    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. PMID:23447006


    Directory of Open Access Journals (Sweden)



    Full Text Available This paper presents the design of an artificial neural network (ANN based intelligent pressure sensor to measure pressure in the range 0-100 psig with high accuracy and temperature compensation. A capacitive pressure sensor detects the applied pressure by means of elastic deflection of diaphragm. A Modified Schering Bridge Signal Conditioning Circuit (MSB-SCC converts the change in capacitance of the sensor into an equivalent voltage. The effect of change in environmental conditions, especially effect of ambient temperature on the pressure sensor and component drifts, stray effects associated with MSB-SCC introduce nonlinearity and cross-sensitivity errors in the output readout. The ANN trained with Levenberg-Marquardt (LM algorithm incorporates the intelligence into sensor signal conditioning circuit through a microcontroller unit to reduce the nonlinearity effects and compensate the cross-sensitivity errors.The LM algorithm shows better performance in terms of the linearity error in comparison with Broyden-Fletcher-Goldfarb-Shanno (BFGS and the Scaled Conjugate Gradient (SCG algorithms. The proposed method is experimentally verified at various temperatures and it provides voltage readout within ±0.8% of full-scale reading over a range of temperature variations from 10 °C to 35°C.

  12. Wax Spreading in Paper under Controlled Pressure and Temperature. (United States)

    Hong, Wei; Zhou, Jing; Kanungo, Mandakini; Jia, Nancy; Dinsmore, Anthony D


    This work describes a novel rapid method to fabricate high-resolution paper-based microfluidic devices using wax-ink-based printing. This study demonstrates that both temperature and pressure are important knobs in controlling the device resolution. High-resolution lines and patterns were obtained by heating the paper asymmetrically from one side up to 110 °C while applying pressure up to 49 kPa. Starting with wax lines with an initial width of 130 μm, we achieve a thorough penetration through a 190 μm-thick paper with lateral spreading on the front as narrow as 90 μm. The role of temperature and pressure are systematically studied and compared with the prediction of the Lucas-Washburn equation. We found that the temperature dependence of spreading can be explained by the viscosity change of the wax, according to the Lucas-Washburn equation. The pressure dependence deviates from Lucas-Washburn behavior because of compression of the paper. An optimal condition for achieving full depth penetration of the wax yet minimizing lateral spreading is suggested after exploring various parameters including temperature, pressure, and paper type. These findings could lead to a rapid roll-to-roll fabrication of high-resolution paper-based diagnostic devices.

  13. A Model for the Determination of Diffusion Capacity Under Non-Standard Temperature and Pressure Conditions

    Directory of Open Access Journals (Sweden)

    Eitzinger Bernhard


    Full Text Available The diffusion capacity of cigarette paper has been reported to be an important parameter in relation to the self-extinguishment of cigarettes and also in relation to carbon monoxide yields. Although the diffusion capacity is routinely measured and instruments for this measurement have been available for several years, differences between measured values obtained on the same paper sample but on different instruments or in different laboratories may be substantial and may make it difficult to use these values, for example, as a basis for paper specifications. Among several reasons, deviations of temperature and pressure from standard conditions, especially within the measurement chamber of the instrument, may contribute to the high variation in diffusion capacity data. Deviations of temperature and pressure will have an influence on the gas flow rates, the diffusion processes inside the measurement chamber and consequently the measured CO2 concentration. Generally, the diffusion capacity is determined from a mathematical model, which describes the diffusion processes inside the measurement chamber. Such models provide the CO2 concentration in the outflow gas for a given diffusion capacity. For practical applications the inverse model is needed, that is, the diffusion capacity shall be determined from a measured CO2 concentration. Often such an inverse model is approximated by a polynomial, which, however, is only valid for standard temperature and pressure. It is shown that relative approximation errors from such polynomials, even without temperature and pressure deviations, cannot always be neglected and it is proposed to eliminate such errors by direct inversion of the model with a comparably simple iterative method. A model which includes temperature and pressure effects is described and the effects of temperature and pressure deviations on the diffusion capacity are theoretically estimated by comparing the output of a model with and without

  14. Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors (United States)

    Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender


    We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 C. The previously observed maximum drift of +/- 10 mV of the reference offset voltage at 600 C was reduced to within +/- 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 C.

  15. Soft Wire Seals For High Temperatures And Pressures (United States)

    Tsou, Peter


    Soft metal wires used to make O-ring and similar seals for vessels, flanges, and fittings subject to pressures equal to or greater than 1,000 psi and temperatures equal to or greater than 100 degrees C. Seals containing soft metal wires made inexpensively because fabricated to looser tolerances like those of lower-temperature, lower-pressure elastomeric-O-ring seals, which they resemble. Seals also made with noncircular grooves and with soft metals other than aluminum. For example, gold performs well, though expensive. For other applications, silver good choice.

  16. Temperature, Humidity, Wind and Pressure Sensors (THWAPS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Ritsche, MT


    The temperature, humidity, wind, and pressure system (THWAPS) provide surface reference values of these measurements for balloon-borne sounding system (SONDE) launches. The THWAPS is located adjacent to the SONDE launch site at the Southern Great Plains (SGP) Central Facility. The THWAPS system is a combination of calibration-quality instruments intended to provide accurate measurements of meteorological conditions near the surface. Although the primary use of the system is to provide accurate surface reference values of temperature, pressure, relative humidity (RH), and wind velocity for comparison with radiosonde readings, the system includes a data logger to record time series of the measured variables.

  17. Pressure and Temperature Sensors Using Two Spin Crossover Materials

    Directory of Open Access Journals (Sweden)

    Catalin-Maricel Jureschi


    Full Text Available The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices.

  18. Pressure and temperature effects in homopolymer blends and diblock copolymers

    DEFF Research Database (Denmark)

    Frielinghaus, H.; Schwahn, D.; Mortensen, K.


    contribution of the Flory-Huggins parameter at larger pressure fields. This gives rise to a shift of the phase boundaries to higher temperatures and to a strong reduction of the Ginzburg parameter. Diblock copolymers show a different behavior. Neither the entropic term of the Flory-Huggins parameter nor......Thermal composition fluctuations in homopolymer mer blends and diblock copolymers were studied with SANS in varying pressure and temperature fields. For homopolymers we find a quite consistent behavior: The dominating effect of compressibility or packing leads to a reduction of the entropic...

  19. Pressure and temperature development in solar heating system during stagnation

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Chen, Ziqian


    This paper presents an investigation of stagnation in solar collectors and the effects it will have on the collector loop. At a laboratory test stand at the Technical University of Denmark, a pressurized solar collector loop was designed to test different numbers of collectors and different designs...... of the pipes of the solar collector loop. During the investigation the pre-pressure of the expansion vessel and system filling pressure was changed. The investigations showed that a large pressurised expansion vessel will protect the collector loop from critically high temperatures as long as the solar...

  20. Season, temperature and blood pressure: a complex interaction. (United States)

    Modesti, Pietro Amedeo


    An increase in blood pressure values measured during winter either in the office, at home, or at ambulatory blood pressure monitoring was consistently observed. Besides potentially contributing to increase the risk for cardiovascular events during the cold season, long term blood pressure variations can influence results of clinical trials, epidemiological surveys, and require personalized management of antihypertensive medications in the single patient. Those variations are often considered as an effect of climate, due to the close correlation observed in various countries and in different settings between temperature and blood pressure among children, adults, and specially the elderly. However, obtaining true measurements of exposition is a main problem when investigating the effects of climate on human health especially when the aim is to disentangle the effects of climate from those of seasonality. The aim of the present note is not to provide a complete review of the literature demonstrating the implications of seasonal blood pressure changes in the clinical and experimental setting; rather it is to consider methodological aspects useful to investigate the interaction between seasonality and temperature on blood pressure and to make health care providers aware of the implications of environmental factors on blood pressure in clinical and research settings. © 2013.


    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi


    It is well known that the fluid phase equilibria can be represented by a number of {gamma}-models , but unfortunately most of them do not function well under high temperature. In this calculation, we mainly investigate the performance of UNIQUAC and NRTL models under high temperature, using temperature dependent parameters rather than using the original formulas. the other feature of this calculation is that we try to relate the excess Gibbs energy G{sup E}and enthalpy of mixing H{sup E}simultaneously. In other words, we will use the high temperature and pressure G{sup E} and H{sup E}data to regress the temperature dependant parameters to find out which model and what kind of temperature dependant parameters should be used.

  2. Recommended reference materials for realization of physicochemical properties pressure-volume-temperature relationships

    CERN Document Server

    Herington, E F G


    Recommended Reference Materials for Realization of Physicochemical Properties presents recommendations of reference materials for use in measurements involving physicochemical properties, namely, vapor pressure; liquid-vapor critical temperature and critical pressure; orthobaric volumes of liquid and vapor; pressure-volume-temperature properties of the unsaturated vapor or gas; and pressure-volume-temperature properties of the compressed liquid. This monograph focuses on reference materials for vapor pressures at temperatures up to 770 K, as well as critical temperatures and critical pressures

  3. High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; G.K. Housley; K. DeWall; L. Moore-McAteer


    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this

  4. From anthracites to graphite: influences of temperature, pressure and shear

    Energy Technology Data Exchange (ETDEWEB)

    Beyssac, O.; Goffe, B.; Rouzaud, J.-N.; Clinard, C.; Cassareuil, J.; Catel, N. [Ecole Normale Superieure, Paris (France). Laboratoire de Geologie


    In order to study natural graphitization, a homogenous series of organic matter bearing metasediments were sampled. The structural and microtextural evolution of organic matter was followed using Raman spectroscopy and transmission electron microscopy. Natural graphitization was shown to be enhanced by temperature, pressure and shear. 9 refs., 2 figs.

  5. "Deflategate": Time, Temperature, and Moisture Effects on Football Pressure (United States)

    Blumenthal, Jack; Beljak, Lauren; Macatangay, Dahlia-Marie; Helmuth-Malone, Lilly; McWilliams, Catharina; Raptis, Sofia


    In a recent paper in "The Physics Teacher (TPT)", DiLisi and Rarick used the National Football League "Deflategate" controversy to introduce to physics students the physics of a bouncing ball. In this paper, we measure and analyze the environmental effects of time, ambient temperature, and moisture on the internal pressure of…

  6. Structural stability of high entropy alloys under pressure and temperature

    DEFF Research Database (Denmark)

    Ahmad, Azkar S.; Su, Y.; Liu, S. Y.


    The stability of high-entropy alloys (HEAs) is a key issue before their selection for industrial applications. In this study, in-situ high-pressure and high-temperature synchrotron radiation X-ray diffraction experiments have been performed on three typical HEAs Ni20Co20Fe20Mn20Cr20, Hf25Nb25Zr25Ti...

  7. Mixture including hydrogen and hydrocarbon having pressure-temperature stability (United States)

    Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)


    The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

  8. 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...

  9. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    With dwindling easily accessible oil and gas resources, more and more exploration and production activities in the oil industry are driven to technically challenging environments such as unconventional resources and deeper formations. The temperature and pressure can become extremely high, e.g., up...

  10. 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

  11. 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)

  12. Pressure and temperature dependence of growth and morphology of Escherichia coli: Experiments and Stochastic Model

    CERN Document Server

    Kumar, Pradeep


    We have investigated the growth of Escherichia coli E.coli, a mesophilic bacterium, as a function of pressure $P$ and temperature $T$. E.coli can grow and divide in a wide range of pressure (1-400atm) and temperature ($23-40^{\\circ}$C). For $T>30^{\\circ}$ C, the division time of E.coli increases exponentially with pressure and exhibit a departure from exponential behavior at pressures between 250-400 atm for all the temperatures studied in our experiments. For $T<30^{\\circ}$ C, the division time shows an anomalous dependence on pressure -- first decreases with increasing pressure and then increases upon further increase of pressure. The sharp change in division time is followed by a sharp change in phenotypic transition of E. Coli at high pressures where bacterial cells switch to an elongating cell type. We propose a model that this phenotypic changes in bacteria at high pressures is an irreversible stochastic process whereas the switching probability to elongating cell type increases with increasing press...

  13. Combined effects of temperature, pressure, and co-solvents on the polymerization kinetics of actin. (United States)

    Rosin, Christopher; Estel, Kathrin; Hälker, Jessica; Winter, Roland


    In vivo studies have shown that the cytoskeleton of cells is very sensitive to changes in temperature and pressure. In particular, actin filaments get depolymerized when pressure is increased up to several hundred bars, conditions that are easily encountered in the deep sea. We quantitatively evaluate the effects of temperature, pressure, and osmolytes on the kinetics of the polymerization reaction of actin by high-pressure stopped-flow experiments in combination with fluorescence detection and an integrative stochastic simulation of the polymerization process. We show that the compatible osmolyte trimethylamine-N-oxide is not only able to compensate for the strongly retarding effect of chaotropic agents, such as urea, on actin polymerization, it is also able to largely offset the deteriorating effect of pressure on actin polymerization, thereby allowing biological cells to better cope with extreme environmental conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Modeling Low-temperature Geochemical Processes (United States)

    Nordstrom, D. K.


    Geochemical modeling has become a popular and useful tool for a wide number of applications from research on the fundamental processes of water-rock interactions to regulatory requirements and decisions regarding permits for industrial and hazardous wastes. In low-temperature environments, generally thought of as those in the temperature range of 0-100 °C and close to atmospheric pressure (1 atm=1.01325 bar=101,325 Pa), complex hydrobiogeochemical reactions participate in an array of interconnected processes that affect us, and that, in turn, we affect. Understanding these complex processes often requires tools that are sufficiently sophisticated to portray multicomponent, multiphase chemical reactions yet transparent enough to reveal the main driving forces. Geochemical models are such tools. The major processes that they are required to model include mineral dissolution and precipitation; aqueous inorganic speciation and complexation; solute adsorption and desorption; ion exchange; oxidation-reduction; or redox; transformations; gas uptake or production; organic matter speciation and complexation; evaporation; dilution; water mixing; reaction during fluid flow; reaction involving biotic interactions; and photoreaction. These processes occur in rain, snow, fog, dry atmosphere, soils, bedrock weathering, streams, rivers, lakes, groundwaters, estuaries, brines, and diagenetic environments. Geochemical modeling attempts to understand the redistribution of elements and compounds, through anthropogenic and natural means, for a large range of scale from nanometer to global. "Aqueous geochemistry" and "environmental geochemistry" are often used interchangeably with "low-temperature geochemistry" to emphasize hydrologic or environmental objectives.Recognition of the strategy or philosophy behind the use of geochemical modeling is not often discussed or explicitly described. Plummer (1984, 1992) and Parkhurst and Plummer (1993) compare and contrast two approaches for

  15. Low Temperature and High Pressure Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.; Martinez-Frias, J.; Garcia-Villazana, O.


    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures.

  16. Releasing H2 molecules with a partial pressure difference without the use of temperature (United States)

    Lee, Hoonkyung; Huang, Bing; Duan, Wenhui; Ihm, Jisoon


    Using the pseudopotential density-functional method as well as equilibrium thermodynamic functions, we explore the process of releasing H2 molecules adsorbed on a transition-metal atom caused by the hydrogen-ammonia partial pressure difference. The H2 molecules bind to a transition-metal atom at H2 pressure- NH3 pressure-temperature 50atm-10-9atm-25°C , and they are released at 3atm-10-6atm-25°C . This process involves the same mechanism responsible for carbon monoxide poisoning of hemoglobin with the O2-CO partial pressure difference. We show that our findings can be applicable to an approach to induce hydrogen desorption on nanostructured hydrogen-storage materials without the need for increasing temperature.

  17. Comparison of the existing internally consistent pressure scales at high pressures and high temperatures (United States)

    Cynn, Hyunchae; Baer, B. J.; MacLeod, S. G.; Evans, W. J.; Lipp, M. J.; Klepeis, J. P.; Jenei, Zs.; Chen, J. Y.; Catalli, K.; Popov, D.; Park, C. Y.


    There have been several efforts to determine internally consistent pressure scales for static diamond anvil high pressure study. We decide to extend the choice of pressure scales to include W and Cu. A recent study of Cu claims that electronic theory can constrain cold curve and possibly room temperature isotherm (Greeff et al., 2006, JPCS). We will present our comparison of 6 different pressure scales in regards with the suggested Cu EOS. We have measured angle-dispersive x-ray diffraction of Au, Pt, W, Cu, Ne, and NaCl to directly compare with the current existing EOS. We will also discuss discrepancies in the precise determination of pressure of phase transformations.

  18. 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

  19. The effect of ambient temperature and barometric pressure on ambulatory blood pressure variability. (United States)

    Jehn, Megan; Appel, Lawrence J; Sacks, Frank M; Miller, Edgar R


    The effect of ambient temperature on cardiovascular disease has previously been studied. Less known are the effects of climate on blood pressure (BP) regulation, specifically, the role of temperature on BP variability. We investigated the effect of temperature and barometric pressure on ambulatory BP variability in 333 men and women with above-optimal BP or stage 1 hypertension participating in the Dietary Approaches to Stop Hypertension (DASH) multicenter feeding trial. Each subject consumed the same diet for 3 weeks. Daytime, nighttime, and 24-h BP were recorded by ambulatory BP monitoring (ABPM). Climatologic data were obtained from local meteorologic centers. After adjustment for body mass index (BMI), age, sex, baseline clinic systolic BP, and clinical center, systolic BP variability was inversely associated with 24-h temperature (P =.005) and daytime temperature (P =.006). There was no observed association between BP variability and barometric pressure. There was a significant trend of increasing nighttime systolic BP and diastolic BP with increasing temperature, but these results did not persist after adjustment for confounding variables. During periods of cold weather, an increase in BP variability may complicate the diagnosis and management of hypertension and may contribute to the high cardiovascular mortality observed in the winter.

  20. Surface processes of dust particles in low pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Stoffels, E.; Stoffels, W.W.; Kersten, H.; Swinkels, G.H.P.M.; Kroesen, G.M.W. [Technische Univ. Eindhoven (Netherlands). Dept. of Physics


    This paper presents several aspects of applied dusty plasma research. New applications of dust particles are emerging; there is growing demand for particles with special properties, and for particle-seeded composite materials. Low-pressure plasmas offer a unique possibility of confinement, control and fine tailoring of particle properties. The role of low-pressure technology in surface modification (coating) of dust grains is discussed and illustrated with examples. Fundamental research related to industrial particle treatment aims at the understanding the surface chemistry of processing. More specifically, the nature of plasma-particle interactions must be resolved. Heat exchange and particle temperature, discussed in this paper, are of major interest in the applied dusty plasma studies. (orig.)

  1. Iterative Boltzmann plot method for temperature and pressure determination in a xenon high pressure discharge lamp

    Energy Technology Data Exchange (ETDEWEB)

    Zalach, J.; Franke, St. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)


    The Boltzmann plot method allows to calculate plasma temperatures and pressures if absolutely calibrated emission coefficients of spectral lines are available. However, xenon arcs are not very well suited to be analyzed this way, as there are only a limited number of lines with atomic data available. These lines have high excitation energies in a small interval between 9.8 and 11.5 eV. Uncertainties in the experimental method and in the atomic data further limit the accuracy of the evaluation procedure. This may result in implausible values of temperature and pressure with inadmissible uncertainty. To omit these shortcomings, an iterative scheme is proposed that is making use of additional information about the xenon fill pressure. This method is proved to be robust against noisy data and significantly reduces the uncertainties. Intentionally distorted synthetic data are used to illustrate the performance of the method, and measurements performed on a laboratory xenon high pressure discharge lamp are analyzed resulting in reasonable temperatures and pressures with significantly reduced uncertainties.

  2. High Temperature High Pressure Thermodynamic Measurements for Coal Model Compounds

    Energy Technology Data Exchange (ETDEWEB)

    John C. Chen; Vinayak N. Kabadi


    The overall objective of this project is to develop a better thermodynamic model for predicting properties of high-boiling coal derived liquids, especially the phase equilibria of different fractions at elevated temperatures and pressures. The development of such a model requires data on vapor-liquid equilibria (VLE), enthalpy, and heat capacity which would be experimentally determined for binary systems of coal model compounds and compiled into a database. The data will be used to refine existing models such as UNIQUAC and UNIFAC. The flow VLE apparatus designed and built for a previous project was upgraded and recalibrated for data measurements for thk project. The modifications include better and more accurate sampling technique and addition of a digital recorder to monitor temperature, pressure and liquid level inside the VLE cell. VLE data measurements for system benzene-ethylbenzene have been completed. The vapor and liquid samples were analysed using the Perkin-Elmer Autosystem gas chromatography.

  3. Pulse Radiolysis at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Christensen, H.; Sehested, Knud


    A cell for pulse radiolytic measurements up to temperatures of 320°C and pressures of 14 MPa is constructed. The activation energy of the reaction OH + Cu2+ is determined to 13.3 kJ × mol−1 (3.2 kcal × mol−1). A preliminary study of the reaction e−aq + e−aq yields an activation energy of 22 k...

  4. High-Pressure Minerals in RC106: Formation at Modest Shock Pressures and very High Temperatures (United States)

    Sharp, T. G.; Trickey, R.; de Carli, P. S.; Xie, Z.


    The controversy concerning the pressures required to produce shock effects in meteorites began with the interpretation that shock veins in chondrites crystallize at pressures about 25 GPa (Chen et al. 1996) rather than the 50 -90 GPa inferred from “calibration” of shock effects from shock-recovery experiments (Stöffler et al. 1991). The 25 GPa estimate was based on phase equilibrium data for crystallization. The transformation of mafic silicate minerals into their high-pressure polymorphs within shock veins has been used as evidence for local excursions to extreme pressure and temperature. Here we present new data from the RC106 L6 S6 chondrite, that illustrates the importance of high temperatures and long shock durations. The shock vein consists of entrained fragments of chondrite in a matirix of quenched silicate and metal-sulfide melts. The silicate melt crystallized majorite-pyrope garnet and ferropericlase throughout the vein, with course (10-15 µm) granular garnets in the vein center and sub-µm dendritic garnets at the vein margins. All of the entrained olivine in the melt vein was transformed into ringwoodite. A distinct nanocrystalline boundary zone, composed of predominantly ringwoodite, occurs along much of the melt vein margin as a continuous blue layer. These zones contain quenched droplets of metal-sulfide melt that suggest a liquid origin. Some of the olivine in contact with the boundary zones is partially transformed to ringwoodite. The mineralogy and texture of the vein matrix indicate that the silicate liquid was quenched at approximately 23 GPa by conduction of heat into the surrounding chondrite host. We infer that boundary zones represent vein margin minerals that were melted by the influx of heat from the super heated melt vein. One explanation for the discrepancy in pressure estimates between shock recovery experiments and melt-vein crystallization has been that crystallization occurs during release from a much higher shock pressure

  5. IR Temperature Measurement in Pressure-Shear Plate Impact (United States)

    Jiao, Tong; Malhotra, Pinkesh; Clifton, Rodney; School of Engineering, Brown University Team


    Pressure-Shear Plate Impact (PSPI) experiments on samples sandwiched between two hard plates have been developed previously for measuring the shearing resistance of materials at high strain rates, large inelastic shear strains, and high pressures. To enhance the value of such experiments in developing constitutive models for the dynamic response of materials, concurrent temperature measurements are being pursued by monitoring the infrared radiation emitted from the sample/rear-plate interface. The emitted radiation is collected by fast HgCdTe detectors through a pair of 90o off-axis parabolic reflectors. ZnSe is used as the rear plate (window) because its transmission band (0.6 μm -16 μm) covers an exceptionally wide range of wavelengths - extending beyond the cutoff wavelength of the IR detector. Moreover, ZnSe remains nominally linear-elastic up to a pressure of 12 GPa - encompassing the pressure range for most PSPI experiments. Because temperatures generated in PSPI experiments are modest, the emissivity of the interface is increased by applying a thin layer of SiC at the sample/window interface. The high shearing resistance of SiC ensures that the allowable range of shear stresses is not limited by the presence of the high-emissivity layer. Pilot experiments will be assessed for their potential and limitations. This work is supported by Air Force Office of Scientific Research.

  6. A micro-mechanical analysis and an experimental characterisation of the behavior and the damaging processes of a 16MND5 pressure vessel steel at low temperature; Etude micromecanique et caracterisation experimentale du comportement et de l'endommagement de l'acier de cuve 16MND5 a basses temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Pesci, R


    As part of an important experimental and numerical research program launched by Electricite De France on the 16MND5 pressure vessel steel, sequenced and in-situ tensile tests are realized at low temperatures [-196 C;-60 C]. They enable to associate the observation of specimens, the complete cartography of which has been made with a scanning electron microscope (damaging processes, initiation and propagation of microcracks), with the stress states determined by X-ray diffraction, in order to establish relevant criteria. All these measurements enable to supply a two-scale polycrystalline modeling of behavior and damage (Mori-Tanaka/self-consistent) which is developed concurrently with the experimental characterization. This model proves to be a very efficient one, since it correctly reproduces the influence of temperature experimentally defined: the stress state in ferrite remains less important than in bainite (the difference never exceeds 150 MPa), whereas it is much higher in cementite. The heterogeneity of strains and stresses for each crystallographic orientation is well rendered; so is cleavage fracture normal to the {l_brace}100{r_brace} planes in ferrite (planes identified by electron back scattered diffraction during an in-situ tensile test at -150 C), which occurs sooner when temperature decreases, for a constant stress of about 700 MPa in this phase. (author)

  7. Sterilization by high hydrostatic pressure : increasing efficiency and product quality by improved temperature control

    NARCIS (Netherlands)

    Heij, de W.B.C.; Schepdael, van L.J.M.M.; Moezelaar, R.; Berg, van den R.W.


    A product being pressurized will heat up due to compressive heating. Due to heat transfer, products close to the vessel wall will cool down, a process which may result in a non-homogeneous product temperature profile in radial direction. If the proper technological features are implemented these

  8. Evaluation of catalytic effects in gasification of biomass at intermediate temperature and pressure

    NARCIS (Netherlands)

    Nanou, Pavlina; van Rossum, G.; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.; Lefferts, Leonardus; Seshan, Kulathuiyer


    This paper proposes and examines an alternative thermo-chemical process for biomethane production from lignocellulosic biomass, termed self-gasification. Self-gasification of biomass is envisaged to utilize a high-pressure steam gasifier (30−80 bar) at temperatures of 600−900 °C and to use the

  9. Pressure and temperature effects on optical transitions in cubic GaN (United States)

    Liu, Z. X.; Goñi, A. R.; Syassen, K.; Siegle, H.; Thomsen, C.; Schöttker, B.; As, D. J.; Schikora, D.


    Pressure and temperature effects on optical transitions in cubic GaN grown on a GaAs substrate have been studied by photoluminescence (PL) spectroscopy at hydrostatic pressures up to 9 GPa (10 K) and as a function of temperature (10-300 K) at ambient pressure. The dominant emissions at 10 K and ambient pressure are assigned to the bound-exciton transition (zero-phonon line), the donor-acceptor-pair (DAP) emission, and, tentatively, to the first three LO-phonon replicas of the bound exciton. These PL features shift to higher energy with increasing pressure. The pressure coefficients indicate that the observed recombination processes involve states which are closely related to the band edges. Temperature-induced evolutions from bound to free-exciton (FE) transition and DAP emission to free-to-bound transition are resolved. The binding energies of the FE and donor and acceptor levels in cubic GaN have been determined from the temperature and power-density dependence of the PL emission energies.

  10. The effect of nozzle diameter, injection pressure and ambient temperature on spray characteristics in diesel engine (United States)

    Rhaodah Andsaler, Adiba; Khalid, Amir; Sharifhatul Adila Abdullah, Nor; Sapit, Azwan; Jaat, Norrizam


    Mixture formation of the ignition process is a key element in the diesel combustion as it influences the combustion process and exhaust emission. Aim of this study is to elucidate the effects of nozzle diameter, injection pressure and ambient temperature to the formation of spray. This study investigated diesel formation spray using Computational Fluid Dynamics. Multiphase volume of fluid (VOF) behaviour in the chamber are determined by means of transient simulation, Eulerian of two phases is used for implementation of mixing fuel and air. The detail behaviour of spray droplet diameter, spray penetration and spray breakup length was visualised using the ANSYS 16.1. This simulation was done in different nozzle diameter 0.12 mm and 0.2 mm performed at the ambient temperature 500 K and 700 K with different injection pressure 40 MPa, 70 MPa and 140 MPa. Results show that high pressure influence droplet diameter become smaller and the penetration length longer with the high injection pressure apply. Smaller nozzle diameter gives a shorter length of the breakup. It is necessary for nozzle diameter and ambient temperature condition to improve the formation of spray. High injection pressure is most effective in improvement of formation spray under higher ambient temperature and smaller nozzle diameter.

  11. High Speed Submarine Optical Fiber Communication System:Pressure and Temperature Effects

    Directory of Open Access Journals (Sweden)

    A. A. Mohammed


    Full Text Available In the present paper, the performance of high speed submarine optical fiber cable systems is investigated, taking into account both the pressure and the temperature effects. Both the pressure and the temperature are depth-dependent variables, while both the spectral losses and the dispersion effects are temperature as well as wavelength dependent variables. Two important cases with real fibers are processed: a case with dispersion cancellation and a case without dispersion cancellation. It is found that the ocean pressure (due to the depth shifts the dispersion-free wavelength towards the third communication window. In general, as the depth increases the maximum transmitted bit rate increases in the range of interest. The system capacity as well as the spectral losses, and the dispersion effects are parametrically investigated over wide-range ranges of the set of affecting parameters {wavelength, ocean depth (and consequently the ocean pressure and temperature, and the chemical structure}. Key Words: Submarine Optical Fiber, Undersea Optical Communication, Pressure and Temperature Effects, Transoceanic Optical Communications

  12. Temperature Prediction for High Pressure High Temperature Condensate Gas Flow Through Chokes

    Directory of Open Access Journals (Sweden)

    Changjun Li


    Full Text Available This study developed a theoretical model for predicting the downstream temperatures of high pressure high temperature condensate gas flowing through chokes. The model is composed of three parts: the iso-enthalpy choke model derived from continuity equation and energy conservation equation; the liquid-vapor equilibrium model based on the SRK equation of state (EoS; and the enthalpy model based on the Lee-Kesler EoS. Pseudocritical properties of mixtures, which are obtained by mixing rules, are very important in the enthalpy model, so the Lee-Kesler, Plocker-Knapp, Wong-Sandler and Prausnitz-Gunn mixing rules were all researched, and the combination mixing rules with satisfactory accuracy for high pressure high temperature condensate gases were proposed. The temperature prediction model is valid for both the critical and subcritical flows through different kinds of choke valves. The applications show the model is reliable for predicting the downstream temperatures of condensate gases with upstream pressures up to 85.54 MPa and temperatures up to 93.23 °C. The average absolute errors between the measured and calculated temperatures are expected for less than 2 °C by using the model.

  13. Hybrid DPWM with Process and Temperature Calibration (United States)

    Lu, Jing

    In this thesis, a 12-bit high resolution, power and area efficiency hybrid DPWM with process and temperature calibration is proposed for DPWM controller IC for DC-DC converters. The hybrid structure of DPWM combines a 6-bit differential segmented tapped delay line structure and a 6-bit counter-comparator structure, resulting in a power and area saving solution. Furthermore, the 6-bit differential segmented delay line structure serves as the clock to the high 6-bit counter-comparator structure, thus a high frequency clock is eliminated and power is significantly saved. In order to have simple delay cell and flexible delay time controllability, voltage controlled inverter is adopted to build the differential delay cell, which allows fine-tuning of the delay time. The process and temperature calibration circuit is composed of process and temperature monitors, two 2-bit flash ADCs, and a lookup table. The monitor circuits sense the process and temperature variations, and the flash ADC converts the data into digital code. The lookup table combines both the process and the temperature digital information and provides an appropriate value to the control voltage of the differential delay cell. The complete circuits design has been verified under different corners of CMOS 0.11um process technology node.

  14. Melt processed high-temperature superconductors

    CERN Document Server


    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  15. Development of a low-pressure materials pre-treatment process for improved energy efficiency (United States)

    Lee, Kwanghee; You, Byung Don


    Low pressure materials pre-treatment process has been developed as an alternative to the existing high-temperature sludge drying, limestone calcination, and limonite dehydroxylation. Using the thermodynamic equilibrium relationship between temperature and pressure represented by the Clausius-Clapeyron equation, the operational temperature of these reactions could be lowered at reduced pressure for increased energy efficiency. For industrial sludge drying, the evaporation rate was controlled by interfacial kinetics showing a constant rate with time and significant acceleration in the reaction could be observed with reduced pressure. At this modified reaction rate under low pressure, the rate was also partially controlled by mass transfer. Temperature of limestone calcination was lowered, but the reaction was limited at the calculated equilibrium temperature of the Clausius-Clapeyron equation and slightly higher temperatures were required. The energy consumption during limestone calcination and limonite dehydroxylation were evaluated, where lower processing pressures could enhance the energy efficiency for limestone calcination, but limonite dehydroxylation could not achieve energy-savings due to the greater power consumption of the vacuum pump under lower pressure and reduced temperatures.

  16. 30 CFR 35.21 - Temperature-pressure spray-ignition tests. (United States)


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Temperature-pressure spray-ignition tests. 35... Temperature-pressure spray-ignition tests. (a) Purpose. The purpose of this test shall be to determine the... the pressure vessel and heated to a temperature of 150 °F. The temperature shall be maintained at not...

  17. Atmospheric Pressure Plasma Processing for Polymer Adhesion: A Review

    DEFF Research Database (Denmark)

    Kusano, Yukihiro


    Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant de...

  18. High-temperature technological processes: Thermophysical principles (United States)

    Rykalin, N. N.; Uglov, A. A.; Anishchenko, L. M.

    The book is concerned with the principles of thermodynamics and heat transfer theory underlying high-temperature technological processes. Some characteristics of electromagnetic radiation and heat transfer in solids, liquids, and gases are reviewed, and boundary layer theory, surface phenomena, and phase transitions are examined. The discussion includes an analysis of a number of specific processes, such as treatment by concentrated energy fluxes (electron-beam and laser processing) and plasma machining.

  19. Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea. (United States)

    Bonnefond, Hubert; Grimaud, Ghjuvan; Rumin, Judith; Bougaran, Gaël; Talec, Amélie; Gachelin, Manon; Boutoute, Marc; Pruvost, Eric; Bernard, Olivier; Sciandra, Antoine


    Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submit cells to daily variations of temperature for 7 months. The stress intensity, defined as the amplitude of daily temperature variations, was progressively increased along successive selection cycles. Only the amplitude of the temperature variations were increased, the daily average temperature was kept constant along the experiment. This protocol resulted in a thermal niche increase by 3°C (+16.5%), with an enhancement by 9% of the maximal growth rate. The selection process also affected T. lutea physiology, with a feature generally observed for 'cold-temperature' type of adaptation. The amount of total and neutral lipids was significantly increased, and eventually productivity was increased by 34%. This seven month selection experiment, carried out in a highly dynamic environment, challenges some of the hypotheses classically advanced to explain the temperature response of microalgae.

  20. Combined Effect of Pressure and Temperature on the Viscous Behaviour of All-Oil Drilling Fluids

    Directory of Open Access Journals (Sweden)

    Hermoso J.


    Full Text Available The overall objective of this research was to study the combined influence of pressure and temperature on the complex viscous behaviour of two oil-based drilling fluids. The oil-based fluids were formulated by dispersing selected organobentonites in mineral oil, using a high-shear mixer, at room temperature. Drilling fluid viscous flow characterization was performed with a controlled-stress rheometer, using both conventional coaxial cylinder and non-conventional geometries for High Pressure/High Temperature (HPHT measurements. The rheological data obtained confirm that a helical ribbon geometry is a very useful tool to characterise the complex viscous flow behaviour of these fluids under extreme conditions. The different viscous flow behaviours encountered for both all-oil drilling fluids, as a function of temperature, are related to changes in polymer-oil pair solvency and oil viscosity. Hence, the resulting structures have been principally attributed to changes in the effective volume fraction of disperse phase due to thermally induced processes. Bingham’s and Herschel-Bulkley’s models describe the rheological properties of these drilling fluids, at different pressures and temperatures, fairly well. It was found that Herschel-Bulkley’s model fits much better B34-based oil drilling fluid viscous flow behaviour under HPHT conditions. Yield stress values increase linearly with pressure in the range of temperature studied. The pressure influence on yielding behaviour has been associated with the compression effect of different resulting organoclay microstructures. A factorial WLF-Barus model fitted the combined effect of temperature and pressure on the plastic viscosity of both drilling fluids fairly well, being this effect mainly influenced by the piezo-viscous properties of the continuous phase.

  1. Tantalum strength model incorporating temperature, strain rate and pressure (United States)

    Lim, Hojun; Battaile, Corbett; Brown, Justin; Lane, Matt

    Tantalum is a body-centered-cubic (BCC) refractory metal that is widely used in many applications in high temperature, strain rate and pressure environments. In this work, we propose a physically-based strength model for tantalum that incorporates effects of temperature, strain rate and pressure. A constitutive model for single crystal tantalum is developed based on dislocation kink-pair theory, and calibrated to measurements on single crystal specimens. The model is then used to predict deformations of single- and polycrystalline tantalum. In addition, the proposed strength model is implemented into Sandia's ALEGRA solid dynamics code to predict plastic deformations of tantalum in engineering-scale applications at extreme conditions, e.g. Taylor impact tests and Z machine's high pressure ramp compression tests, and the results are compared with available experimental data. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. Bacterial adaptation to extremes of low temperature and elevated pressure (United States)

    Bartlett, Douglas

    The largest portion of Earth's biosphere is represented by low temperature, high pressure deepsea environments which are exposed to reduced and recalcitrant forms of organic carbon and which are far removed from sun light. Progress that has been made in recent years examining the biodiversity, genomics and genetics of microbial life at great ocean depths will be described. Particular focus will be given to the comparative genomics of members of Colwellia, Photobacterium, Moritella, Shewanella, Psychromonas and Carnobacterium genera. The genomes of piezophiles (high pressure adapted microbes) are characterized by possessing large intergenic regions, large numbers of rRNA operons, rRNA of a modified secondary structure, a reliance on unsaturated and poly-unsaturated fatty acids in their membrane lipids, a diversity of transport and physiological capabilities, and large numbers of transposable elements. Genetic studies in Photobacterium profundum have highlighted roles for extracellular polysaccharide production and DNA replication and protein synthesis in low temperature and high pressure growth. Recent advances in the cultivation of novel piezophiles from a deep-trench environment will also be described.

  3. An additive approach to low temperature zero pressure sintering of bismuth antimony telluride thermoelectric materials (United States)

    Catlin, Glenn C.; Tripathi, Rajesh; Nunes, Geoffrey; Lynch, Philip B.; Jones, Howard D.; Schmitt, Devin C.


    This paper presents an additive-based approach to the formulation of thermoelectric materials suitable for screen printing. Such printing processes are a likely route to such thermoelectric applications as micro-generators for wireless sensor networks and medical devices, but require the development of materials that can be sintered at ambient pressure and low temperatures. Using a rapid screening process, we identify the eutectic combination of antimony and tellurium as an additive for bismuth-antimony-telluride that enables good thermoelectric performance without a high pressure step. An optimized composite of 15 weight percent Sb7.5Te92.5 in Bi0.5Sb1.5Te3 is scaled up and formulated into a screen-printable paste. Samples fabricated from this paste achieve a thermoelectric figure of merit (ZT) of 0.74 using a maximum processing temperature of 748 K and a total thermal processing budget of 12 K-hours.

  4. Modulation of taste processing by temperature. (United States)

    Lemon, Christian H


    Taste stimuli have a temperature that can stimulate thermosensitive neural machinery in the mouth during gustatory experience. Although taste and oral temperature are sometimes discussed as different oral sensory modalities, there is a body of literature that demonstrates temperature is an important component and modulator of the intensity of gustatory neural and perceptual responses. Available data indicate that the influence of temperature on taste, herein referred to as "thermogustation," can vary across taste qualities, can also vary among stimuli presumed to share a common taste quality, and is conditioned on taste stimulus concentration, with neuronal and psychophysical data revealing larger modulatory effects of temperature on gustatory responding to weakened taste solutions compared with concentrated. What is more, thermogustation is evidenced to involve interplay between mouth and stimulus temperature. Given these and other dependencies, identifying principles by which thermal input affects gustatory information flow in the nervous system may be important for ultimately unravelling the organization of neural circuits for taste and defining their involvement with multisensory processing related to flavor. Yet thermal effects are relatively understudied in gustatory neuroscience. Major gaps in our understanding of the mechanisms and consequences of thermogustation include delineating supporting receptors, the potential involvement of oral thermal and somatosensory trigeminal neurons in thermogustatory interactions, and the broader operational roles of temperature in gustatory processing. This review will discuss these and other issues in the context of the literature relevant to understanding thermogustation. Copyright © 2017 the American Physiological Society.

  5. Pressure variation of melting temperatures of alkali halides (United States)

    Arafin, Sayyadul; Singh, Ram N.


    The melting temperatures of alkali halides (LiCl, LiF, NaBr, NaCl, NaF, NaI, KBr, KCl, KF, KI, RbBr, RbCl, RbI and CsI) have been evaluated over a wide range of pressures. The solid-liquid transition of alkali halides is of considerable significance due to their huge industrial applications. Our formalism requires a priori knowledge of the bulk modulus and the Grüneisen parameter at ambient conditions to compute Tm at high pressures. The computed values are in very good agreement with the available experimental results. The formalism can satisfactorily be used to compute Tm at high pressures where the experimental data are scanty. Most of the melting curves (Tm versus P) exhibit nonlinear variation with increasing pressure having curvatures downward and exhibit a maximum in some cases like NaCl, RbBr, RbCl and RbI. The values of Tmmax and Pmax corresponding to the maxima of the curves are given.

  6. 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....

  7. Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel


    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.

  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. Comparing Fast Pressure Jump and Temperature Jump Protein Folding Experiments and Simulations. (United States)

    Wirth, Anna Jean; Liu, Yanxin; Prigozhin, Maxim B; Schulten, Klaus; Gruebele, Martin


    The unimolecular folding reaction of small proteins is now amenable to a very direct mechanistic comparison between experiment and simulation. We present such a comparison of microsecond pressure and temperature jump refolding kinetics of the engineered WW domain FiP35, a model system for β-sheet folding. Both perturbations produce experimentally a faster and a slower kinetic phase, and the "slow" microsecond phase is activated. The fast phase shows differences between perturbation methods and is closer to the downhill limit by temperature jump, but closer to the transiently populated intermediate limit by pressure jump. These observations make more demands on simulations of the folding process than just a rough comparison of time scales. To complement experiments, we carried out several pressure jump and temperature jump all-atom molecular dynamics trajectories in explicit solvent, where FiP35 folded in five of the six simulations. We analyzed our pressure jump simulations by kinetic modeling and found that the pressure jump experiments and MD simulations are most consistent with a 4-state kinetic mechanism. Together, our experimental and computational data highlight FiP35's position at the boundary where activated intermediates and downhill folding meet, and we show that this model protein is an excellent candidate for further pressure jump molecular dynamics studies to compare experiment and modeling at the folding mechanism level.

  10. A sensor for combined temperature, pressure, and refractive index detection


    Thomas Reinsch; Kort Bremer; Elfed Lewis; Gabriel Leen; Steffen Lochmann


    A sensor (1) has a light conductor (2) having a grating (FBG), a cavity (5), and a transparent cavity end wall (4), a light emitter for directing light through the conductor, and a light detector for detecting reflected light, and a processor. The processor is adapted to analyse light reflected due to the grating (FBG, 6) to determine an indication of temperature, light reflected from the end (7) of the cavity (5) to determine an indication of pressure, and also light reflected from the outer...

  11. Low Temperature Irradiation Embrittlement of Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The embrittlement trend curve development project for HFIR reactor pressure vessel (RPV) steels was carried out with three major tasks. Which are (1) data collection to match that used in HFIR steel embrittlement trend published in 1994 Journal Nuclear Material by Remec et. al, (2) new embrittlement data of A212B steel that are not included in earlier HFIR RPV trend curve, and (3) the adjustment of nil-ductility-transition temperature (NDTT) shift data with the consideration of the irradiation temperature effect. An updated HFIR RPV steel embrittlement trend curve was developed, as described below. NDTT( C) = 23.85 log(x) + 203.3 log (x) + 434.7, with 2- uncertainty of 34.6 C, where parameter x is referred to total dpa. The developed update HFIR RPV embrittlement trend curve has higher embrittlement rate compared to that of the trend curve developed in 1994.

  12. Combining pressure and temperature control in dynamics on energy landscapes (United States)

    Hoffmann, Karl Heinz; Christian Schön, J.


    Complex systems from science, technology or mathematics usually appear to be very different in their specific dynamical evolution. However, the concept of an energy landscape with its basins corresponding to locally ergodic regions separated by energy barriers provides a unifying approach to the description of complex systems dynamics. In such systems one is often confronted with the task to control the dynamics such that a certain basin is reached with the highest possible probability. Typically one aims for the global minimum, e.g. when dealing with global optimization problems, but frequently other local minima such as the metastable compounds in materials science are of primary interest. Here we show how this task can be solved by applying control theory using magnesium fluoride as an example system, where different modifications of MgF2 are considered as targets. In particular, we generalize previous work restricted to temperature controls only and present controls which simultaneously adjust temperature and pressure in an optimal fashion.

  13. The Pressure-Temperature Regime of Iraq during the Period of 1948–2013

    Directory of Open Access Journals (Sweden)

    Yu.P. Perevedentsev


    Full Text Available We have considered spatiotemporal changes in the pressure-temperature regime at the territory of Iraq and Middle Eastern countries, which is limited by the following geographical coordinates: 27.5–37.5° N, 37.5–50.0° E. The initial data have been obtained from NCEP/NCAR reanalysis in the nodes of 2.5° × 2.5° grids, as well as from the indices of atmospheric circulation during the period of 1948–2013. Statistical processing of the material and construction of the linear trends and composites have allowed to reveal the dynamics of changes in the air temperature and pressure, its dependence on fluctuations in the atmospheric circulation. A tendency has been revealed towards a decrease in the temperature during the cold period and its increase during the warm period. Deviations (anomalies of the distribution of actual temperature and atmospheric pressure from the climatological norm have been estimated. Maps of temperature and pressure distribution in the regions have been created.

  14. Predicting fluorescence quantum yield for anisole at elevated temperatures and pressures (United States)

    Wang, Q.; Tran, K. H.; Morin, C.; Bonnety, J.; Legros, G.; Guibert, P.


    Aromatic molecules are promising candidates for using as a fluorescent tracer for gas-phase scalar parameter diagnostics in a drastic environment like engines. Along with anisole turning out an excellent temperature tracer by Planar Laser-Induced Fluorescence (PLIF) diagnostics in Rapid Compression Machine (RCM), its fluorescence signal evolution versus pressure and temperature variation in a high-pressure and high-temperature cell have been reported in our recent paper on Applied Phys. B by Tran et al. Parallel to this experimental study, a photophysical model to determine anisole Fluorescence Quantum Yield (FQY) is delivered in this paper. The key to development of the model is the identification of pressure, temperature, and ambient gases, where the FQY is dominated by certain processes of the model (quenching effect, vibrational relaxation, etc.). In addition to optimization of the vibrational relaxation energy cascade coefficient and the collision probability with oxygen, the non-radiative pathways are mainly discussed. The common non-radiative rate (intersystem crossing and internal conversion) is simulated in parametric form as a function of excess vibrational energy, derived from the data acquired at different pressures and temperatures from the literature. A new non-radiative rate, namely, the equivalent Intramolecular Vibrational Redistribution or Randomization (IVR) rate, is proposed to characterize anisole deactivated processes. The new model exhibits satisfactory results which are validated against experimental measurements of fluorescence signal induced at a wavelength of 266 nm in a cell with different bath gases (N2, CO2, Ar and O2), a pressure range from 0.2 to 4 MPa, and a temperature range from 473 to 873 K.

  15. 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 ...

  16. Deflagration Behavior of PBX 9501 at Elevated Temperature and Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Maienschein, J L; Koerner, J G


    We report the deflagration behavior of PBX 9501 at pressures up to 300 MPa and temperatures of 150-180 C where the sample has been held at the test temperature for several hours before ignition. The purpose is to determine the effect on the deflagration behavior of material damage caused by prolonged exposure to high temperature. This conditioning is similar to that experienced by an explosive while it being heated to eventual explosion. The results are made more complicated by the presence of a significant thermal gradient along the sample during the temperature ramp and soak. Three major conclusions are: the presence of nitroplasticizer makes PBX 9501 more thermally sensitive than LX-04 with an inert Viton binder; the deflagration behavior of PBX 9501 is more extreme and more inconsistent than that of LX-04; and something in PBX 9501 causes thermal damage to 'heal' as the deflagration proceeds, resulting in a decelerating deflagration front as it travels along the sample.


    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi


    The flow VLE apparatus designed and built for a previous project was upgraded and recalibrated for data measurements for this project. The modifications include better and more accurate sampling technique, addition of a digital recorder to monitor temperature and pressure inside the VLE cell, and a new technique for remote sensing of the liquid level in the cell. VLE data measurements for three binary systems, tetralin-quinoline, benzene--ethylbenzene and ethylbenzene--quinoline, have been completed. The temperature ranges of data measurements were 325 C to 370 C for the first system, 180 C to 300 C for the second system, and 225 C to 380 C for the third system. The smoothed data were found to be fairly well behaved when subjected to thermodynamic consistency tests. SETARAM C-80 calorimeter was used for incremental enthalpy and heat capacity measurements for benzene--ethylbenzene binary liquid mixtures. Data were measured from 30 C to 285 C for liquid mixtures covering the entire composition range. An apparatus has been designed for simultaneous measurement of excess volume and incremental enthalpy of liquid mixtures at temperatures from 30 C to 300 C. The apparatus has been tested and is ready for data measurements. A flow apparatus for measurement of heat of mixing of liquid mixtures at high temperatures has also been designed, and is currently being tested and calibrated.

  18. Automated measurement of pressure injury through image processing. (United States)

    Li, Dan; Mathews, Carol


    To develop an image processing algorithm to automatically measure pressure injuries using electronic pressure injury images stored in nursing documentation. Photographing pressure injuries and storing the images in the electronic health record is standard practice in many hospitals. However, the manual measurement of pressure injury is time-consuming, challenging and subject to intra/inter-reader variability with complexities of the pressure injury and the clinical environment. A cross-sectional algorithm development study. A set of 32 pressure injury images were obtained from a western Pennsylvania hospital. First, we transformed the images from an RGB (i.e. red, green and blue) colour space to a YCb Cr colour space to eliminate inferences from varying light conditions and skin colours. Second, a probability map, generated by a skin colour Gaussian model, guided the pressure injury segmentation process using the Support Vector Machine classifier. Third, after segmentation, the reference ruler - included in each of the images - enabled perspective transformation and determination of pressure injury size. Finally, two nurses independently measured those 32 pressure injury images, and intraclass correlation coefficient was calculated. An image processing algorithm was developed to automatically measure the size of pressure injuries. Both inter- and intra-rater analysis achieved good level reliability. Validation of the size measurement of the pressure injury (1) demonstrates that our image processing algorithm is a reliable approach to monitoring pressure injury progress through clinical pressure injury images and (2) offers new insight to pressure injury evaluation and documentation. Once our algorithm is further developed, clinicians can be provided with an objective, reliable and efficient computational tool for segmentation and measurement of pressure injuries. With this, clinicians will be able to more effectively monitor the healing process of pressure injuries

  19. High-throughput processes for industrially scalable deposition of zinc oxide at atmospheric pressure

    NARCIS (Netherlands)

    Illiberi, A.; Grob, F.; Kniknie, B.; Frijters, C.; Deelen, J. van; Poodt, P.; Beckers, E.H.A.; Bolt, P.J.


    ZnO films have been grown on a moving glass substrate by high temperature (480 0C) chemical vapour deposition (CVD) and low temperature (200 0C) plasma enhanced CVD (PE-CVD) process at atmospheric pressure. Deposition rates above 7 nm/s have been achieved for substrate speeds from 20 to 500 mm/min.


    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.

  1. Numerical modelling of combustion processes at elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Anany, Mohammed Nabil


    As more and more CO{sub 2} quantities are discharged into the atmosphere from flue gases due to fossil fuel combustion, increasing concerns over greenhouse gas emissions have caused extensive research to be directed to the field of new power generation cycles that enable CO{sub 2} capture and storage. Raising the pressure of the coal conversion enables economic separation of CO{sub 2}. Two technologies working at elevated pressures are, for example, the Integrated Gasification Combines Cycle (IGCC) technology and the pressurised oxy-fuel combustion power cycles. Both Technologies rely on conversion of coal at elevated pressures, and hence enabling the CO{sub 2} separation process. For the numerical simulation of such processes, it has been proven that global models of atmospheric char conversion are neither directly applicable nor extrapolatable for elevated-pressure atmospheres. Therefore, abandoning these global models of char conversion and developing more reliable mechanistic char gasification/combustion models is a key point in being able to successfully predict the char gasification/combustion processes taking place at elevated pressures for these new clean-coal technologies. Since oxygen is, by far, the most efficient oxidising agent, the principal aim of this work is to develop a mechanistic model for Char Burn-Out (CBO) that is capable of providing correct predictions of char oxidation rates for wide ranges of temperature and pressure. Hence, this work also contributes to the work being conducted on the char conversion modelling at elevated pressures. In order to validate the predictions of the model, the finite volume (FV) CFD combustion simulation code AIOLOS has been used. During the course of development of the coal conversion model, a non-dissipative SIMPLEC algorithm (Semi Implicit Method for Pressure Linked Equations Consistent) for non-staggered (collocated) grids has been developed, since its robustness has been proven to be higher than their

  2. Temperature induced development of porous structure of bituminous coal chars at high pressure

    Directory of Open Access Journals (Sweden)

    Natalia Howaniec


    Full Text Available The porous structure of chars affects their reactivity in gasification, having an impact on the course and product distribution of the process. The shape, size and connections between pores determine the mechanical properties of chars, as well as heat and mass transport in thermochemical processing. In the study the combined effects of temperature in the range of 973–1273 °K and elevated pressure of 3 MPa on the development of porous structure of bituminous coal chars were investigated. Relatively low heating rate and long residence time characteristic for the in-situ coal conversion were applied. The increase in the temperature to 1173 °K under pressurized conditions resulted in the enhancement of porous structure development reflected in the values of the specific surface area, total pore volume, micropore area and volume, as well as ratio of the micropore volume to the total pore volume. These effects were attributed to the enhanced vaporization and devolatilization, as well as swelling behavior along the increase of temperature and under high pressure, followed by a collapse of pores over certain temperature value. This proves the strong dependence of the porous structure of chars not only on the pyrolysis process conditions but also on the physical and chemical properties of the parent fuel.

  3. 46 CFR 154.701 - Cargo pressure and temperature control: General. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pressure and temperature control: General. 154.701... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control: General...

  4. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature

    Directory of Open Access Journals (Sweden)

    Liu Gang


    Full Text Available High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were also carried out. The results show that: at the temperatures of 650 ∘C and 700 ∘C, the flow curves exhibit the power-law constitutive relation until peak stress is reached and the deformability is suitable for the HPGF process of Ti-3Al-2.5V alloy tube. The effects of pressurization path on the corner filling process and thickness profile are obvious. The high pressure inflow process can result in temperature difference between the straight wall area and corner area, which makes the thickness profile special. Besides, with the stepped pressurization path, the more constant filling rate and better thickness profile can be obtained.

  5. Creep of Posidonia Shale at Elevated Pressure and Temperature (United States)

    Rybacki, E.; Herrmann, J.; Wirth, R.; Dresen, G.


    The economic production of gas and oil from shales requires repeated hydraulic fracturing operations to stimulate these tight reservoir rocks. Besides simple depletion, the often observed decay of production rate with time may arise from creep-induced fracture closure. We examined experimentally the creep behavior of an immature carbonate-rich Posidonia shale, subjected to constant stress conditions at temperatures between 50 and 200 °C and confining pressures of 50-200 MPa, simulating elevated in situ depth conditions. Samples showed transient creep in the semibrittle regime with high deformation rates at high differential stress, high temperature and low confinement. Strain was mainly accommodated by deformation of the weak organic matter and phyllosilicates and by pore space reduction. The primary decelerating creep phase observed at relatively low stress can be described by an empirical power law relation between strain and time, where the fitted parameters vary with temperature, pressure and stress. Our results suggest that healing of hydraulic fractures at low stresses by creep-induced proppant embedment is unlikely within a creep period of several years. At higher differential stress, as may be expected in situ at contact areas due to stress concentrations, the shale showed secondary creep, followed by tertiary creep until failure. In this regime, microcrack propagation and coalescence may be assisted by stress corrosion. Secondary creep rates were also described by a power law, predicting faster fracture closure rates than for primary creep, likely contributing to production rate decline. Comparison of our data with published primary creep data on other shales suggests that the long-term creep behavior of shales can be correlated with their brittleness estimated from composition. Low creep strain is supported by a high fraction of strong minerals that can build up a load-bearing framework.

  6. Pressure-Volume-Temperature (PVT) Gauging of an Isothermal Cryogenic Propellant Tank Pressurized with Gaseous Helium (United States)

    VanDresar, Neil T.; Zimmerli, Gregory A.


    Results are presented for pressure-volume-temperature (PVT) gauging of a liquid oxygen/liquid nitrogen tank pressurized with gaseous helium that was supplied by a high-pressure cryogenic tank simulating a cold helium supply bottle on a spacecraft. The fluid inside the test tank was kept isothermal by frequent operation of a liquid circulation pump and spray system, and the propellant tank was suspended from load cells to obtain a high-accuracy reference standard for the gauging measurements. Liquid quantity gauging errors of less than 2 percent of the tank volume were obtained when quasi-steady-state conditions existed in the propellant and helium supply tanks. Accurate gauging required careful attention to, and corrections for, second-order effects of helium solubility in the liquid propellant plus differences in the propellant/helium composition and temperature in the various plumbing lines attached to the tanks. On the basis of results from a helium solubility test, a model was developed to predict the amount of helium dissolved in the liquid as a function of cumulative pump operation time. Use of this model allowed correction of the basic PVT gauging calculations and attainment of the reported gauging accuracy. This helium solubility model is system specific, but it may be adaptable to other hardware systems.

  7. Atmospheric Pressure Low Temperature Plasma System for Additive Manufacturing (United States)

    Burnette, Matthew; Staack, David


    There is growing interest in using plasmas for additive manufacturing, however these methods use high temperature plasmas to melt the material. We have developed a novel technique of additive manufacturing using a low temperature dielectric barrier discharge (DBD) jet. The jet is attached to the head of a 3D printer to allow for precise control of the plasma's location. Various methods are employed to deposit the material, including using a vaporized precursor or depositing a liquid precursor directly onto the substrate or into the plasma via a nebulizer. Various materials can be deposited including metals (copper using copper (II) acetylacetonate), polymers (PMMA using the liquid monomer), and various hydrocarbon compounds (using alcohols or a 100% methane DBD jet). The rastering pattern for the 3D printer was modified for plasma deposition, since it was originally designed for thermoplastic extrusion. The design constraints for fill pattern selection for the plasma printer are influenced by substrate heating, deposition area, and precursor consumption. Depositions onto pressure and/or temperature sensitive substrates can be easily achieved. Deposition rates range up to 0.08 cm3/hr using tris(2-methoxyethoxy)(vinyl)silane, however optimization can still be done on the system to improve the deposition rate. For example higher concentration of precursor can be combined with faster motion and higher discharge powers to increase the deposition rate without overheating the substrate.

  8. Investigation of the polymerization mechanism of ferrocene doped C60 under high pressure and high temperature. (United States)

    Sun, Shishuai; Cui, Wen; Wang, Shuangming; Liu, Bingbing


    In situ high pressure and high temperature (HPHT) study has been carried out on C60/ferrocene (Fc) in order to detect the process of polymerization and reveal the polymerization mechanism. Pristine C60 was also studied under same conditions for comparison. In both cases, similar types of polymers can be observed after pressure and temperature release, but with different fractions, i.e. a larger amount of 2D polymers were formed in pure C60, while more branch-like polymers were synthesized in C60/Fc, although the most fraction of the polymers is still 1D chain-like polymer in both of the materials. The polymers formed in C60 can be detected both during the "up" run (pressure and temperature increase) and the "down" run (pressure and temperature decrease), while in C60/Fc, the polymers can only be synthesized in the "down" run. The differences between the two cases were attributed to the different initial lattice structures of the two materials and the confinement effect of the dopant. The polymerization mechanism on C60/Fc under HPHT was also revealed in this work.

  9. Ignition and combustion of pyrotechnics at low pressures and at temperature extremes

    Directory of Open Access Journals (Sweden)

    Clive Woodley


    Full Text Available Rapid and effective ignition of pyrotechnic countermeasure decoy flares is vitally important to the safety of expensive military platforms such as aircraft. QinetiQ is conducting experimental and theoretical research into pyrotechnic countermeasure decoy flares. A key part of this work is the development and application of improved models to increase the understanding of the ignition processes occurring for these flares. These models have been implemented in a two-dimensional computational model and details are described in this paper. Previous work has conducted experiments and validated the computational model at ambient temperature and pressure. More recently the computational model has been validated at pressures down to that equivalent to 40,000 feet but at ambient temperature (∼290 K. This paper describes further experimental work in which the ignition delays of the priming material in inert countermeasure decoy flares were determined for pressures down to 40,000 feet and at temperature extremes of −40 °C and 100 °C. Also included in this paper is a comparison of the measured and predicted ignition delays at low pressures and temperature extremes. The agreement between the predicted and measured ignition delays is acceptable.

  10. Essential dynamics of the cold denaturation: pressure and temperature effects in yeast frataxin. (United States)

    Espinosa, Yanis R; Grigera, J Raúl; Caffarena, Ernesto R


    The cold denaturation of globular proteins is a process that can be caused by increasing pressure or decreasing the temperature. Currently, the action mechanism of this process has not been clearly understood, raising an interesting debate on the matter. We have studied the process of cold denaturation using molecular dynamics simulations of the frataxin system Yfh1, which has a dynamic experimental characterization of unfolding at low and high temperatures. The frataxin model here studied allows a comparative analysis using experimental data. Furthermore, we monitored the cold denaturation process of frataxin and also investigated the effect under the high-pressure regime. For a better understanding of the dynamics and structural properties of the cold denaturation, we also analyzed the MD trajectories using essentials dynamic. The results indicate that changes in the structure of water by the effect of pressure and low temperatures destabilize the hydrophobic interaction modifying the solvation and the system volume leading to protein denaturation. Proteins 2016; 85:125-136. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure (United States)

    Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu


    The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

  12. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature


    Liu Gang; Wang Jianlong; Dang Kexin; Yuan Shijian


    High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were ...

  13. Total dissolved gas, barometric pressure, and water temperature data, lower Columbia River, Oregon and Washington, 1996 (United States)

    Tanner, Dwight Q.; Harrison, Howard E.; McKenzie, Stuart W.


    Increased levels of total dissolved gas pressure can cause gas-bubble trauma in fish downstream from dams on the Columbia River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey collected data on total dissolved gas pressure, barometric pressure, water temperature, and dissolved oxygen pressure at 11 stations on the lower Columbia River from the John Day forebay (river mile 215.6) to Wauna Mill (river mile 41.9) from March to September 1996. Methods of data collection, review, and processing are described in this report. Summaries of daily minimum, maximum, and mean hourly values are presented for total dissolved gas pressure, barometric pressure, and water temperature. Hourly values for these parameters are presented graphically. Dissolved oxygen data are not presented in this report because the quality-control data show that the data have poor precision and high bias. Suggested changes to monitoring procedures for future studies include (1) improved calibration procedures for total dissolved gas and dissolved oxygen to better define accuracy at elevated levels of supersaturation and (2) equipping dissolved oxygen sensors with stirrers because river velocities at the shoreline monitoring stations probably cannot maintain an adequate flow of water across the membrane surface of the dissolved oxygen sensor.

  14. Brittle Creep of Tournemire Shale: Orientation, Temperature and Pressure Dependences (United States)

    Geng, Zhi; Bonnelye, Audrey; Dick, Pierre; David, Christian; Chen, Mian; Schubnel, Alexandre


    Time and temperature dependent rock deformation has both scientific and socio-economic implications for natural hazards, the oil and gas industry and nuclear waste disposal. During the past decades, most studies on brittle creep have focused on igneous rocks and porous sedimentary rocks. To our knowledge, only few studies have been carried out on the brittle creep behavior of shale. Here, we conducted a series of creep experiments on shale specimens coming from the French Institute for Nuclear Safety (IRSN) underground research laboratory located in Tournemire, France. Conventional tri-axial experiments were carried under two different temperatures (26˚ C, 75˚ C) and confining pressures (10 MPa, 80 MPa), for three orientations (σ1 along, perpendicular and 45˚ to bedding). Following the methodology developed by Heap et al. [2008], differential stress was first increased to ˜ 60% of the short term peak strength (10-7/s, Bonnelye et al. 2016), and then in steps of 5 to 10 MPa every 24 hours until brittle failure was achieved. In these long-term experiments (approximately 10 days), stress and strains were recorded continuously, while ultrasonic acoustic velocities were recorded every 1˜15 minutes, enabling us to monitor the evolution of elastic wave speed anisotropy. Temporal evolution of anisotropy was illustrated by inverting acoustic velocities to Thomsen parameters. Finally, samples were investigated post-mortem using scanning electron microscopy. Our results seem to contradict our traditional understanding of loading rate dependent brittle failure. Indeed, the brittle creep failure stress of our Tournemire shale samples was systematically observed ˜50% higher than its short-term peak strength, with larger final axial strain accumulated. At higher temperatures, the creep failure strength of our samples was slightly reduced and deformation was characterized with faster 'steady-state' creep axial strain rates at each steps, and larger final axial strain

  15. Pressure transmitting medium Daphne 7474 solidifying at 3.7 GPa at room temperature (United States)

    Murata, Keizo; Yokogawa, Keiichi; Yoshino, Harukazu; Klotz, Stefan; Munsch, Pascal; Irizawa, Akinori; Nishiyama, Mototsugu; Iizuka, Kenzo; Nanba, Takao; Okada, Tahei; Shiraga, Yoshitaka; Aoyama, Shoji


    A pressure transmitting medium named Daphne 7474, which solidifies at Ps=3.7 GPa at room temperature, is presented. The value of Ps increases almost linearly with temperature up to 6.7 GPa at 100 °C. The high pressure realized by a medium at the liquid state allows a higher limit of pressurization, which assures an ideal hydrostatic pressure. We show a volume change against pressure, pressure reduction from room to liquid helium temperature in a clamped piston cylinder cell, pressure distribution and its standard deviation in a diamond anvil cell, and infrared properties, which might be useful for experimental applications.

  16. Temperature diagnostics of a non-thermal plasma jet at atmospheric pressure (United States)

    Schäfer, Jan


    The study reflects the concept of the temperature as a physical quantity resulting from the second thermodynamic law. The reliability of different approaches of the temperature diagnostics of open non-equilibrium systems is discussed using examples of low temperature atmospheric pressure discharges. The focus of this work is a miniaturized non-thermal atmospheric pressure plasma jet for local surface treatment at ambient atmosphere. The micro-discharge is driven with a capacitively coupled radio frequency electric field at 27.12 MHz and fed with argon at rates of about 1 slm through the capillary with an inner diameter of 4 mm. The discharge consists of several contracted filaments with diameter around 300 μm which are rotating azimuthally in the capillary in a self-organized manner. While the measured temperatures of the filament core exceed 700 K, the heat impact on a target below the plasma jet remains limited leading to target temperatures below 400 K. Different kinds of temperatures and energy transport processes are proposed and experimentally investigated. Nevertheless, a reliable and detailed temperature diagnostics is a challenge. We report on a novel diagnostics approach for the spatially and temporally resolved measurement of the gas temperature based on the optical properties of the plasma. Laser Schlieren Deflectometry is adapted to explore temperature profiles of filaments and their behaviour. In parallel, the method demonstrates a fundamental Fermat's principle of minimal energy. Information acquired with this method plays an important role for the optimization of local thin film deposition and surface functionalization by means of the atmospheric pressure plasma jet. The work was supported in part by the Deutsche Forschungsgemeinschaft within SFB-TR 24.

  17. Bed Material and Parameter Variation for a Pressurized Biomass Fluidized Bed Process (United States)

    Puchner, Bernhard; Pfeifer, Christoph; Hofbauer, Hermann

    A pressurized gas at high temperatures with low impurities often is a basic requirement for applications for biomass gasification. Therefore, the Vienna University of Technology, in cooperation with the Austrian Bioenergy Centre, operates a pressurized gasification pilot plant in order to investigate thepressurized gasification process and estimate its potential. Within the scope of this paper this test facility as well as its operation behavioris described. Furthermore the parameters pressure, gasification temperature, lambda value and gasification agent have been investigated regarding to their influenceon the producer gas composition and arepresented and discussed in the following.

  18. Satellite ozone comparisons - Effects of pressure and temperature (United States)

    Olivero, John J.; Barnes, Robert A.


    The effects of errors in determining temperature, pressure, and density in the background atmosphere on the measurements of ozone by two different satellite sensors, the Stratospheric Aerosol and Gas Experiment II (SAGE II) spectrometer aboard the ERB satellite and the solar backscattered UV (SBUV) spectrometer aboard Nimbus 7, were determined. The manner in which the differences in these background atmosphere measurements propagate is demonstrated by making direct comparisons of stratospheric ozone profiles by the SBUV and the SAGE II spectrometers. It is shown that, in regions with strong vertical ozone gradients (particularly at 70 mbar in the tropics), modest differences in vertical positioning could result in differences of 5 to 10 percent in ozone concentrations.

  19. Static pressure and temperature coefficients of laboratory standard microphones

    DEFF Research Database (Denmark)

    Rasmussen, Knud


    on an extended lumped parameter representation of the mechanical and acoustical elements of the microphone, assuming the velocity distribution of the diaphragm to follow the zero-order Bessel function. The extension involves the frequency dependency of the dynamic diaphragm mass and stiffness as well as a first......-order approximation of resonances in the back cavity. It was found that each of the coefficients, for a given type of microphone, can be expressed by a single function when the coefficients are normalized by their low-frequency value and the frequency axis normalized by the individual resonance frequency...... of the microphone. The static pressure and temperature coefficients were determined experimentally for about twenty samples of type BK 4160 and BK 4180 microphones. The results agree almost perfectly with the predictions for BK 4160, while some modifications of the lumped parameter values are called for to make...

  20. Low temperature waste form process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hill, K. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    This study successfully demonstrated process intensification of low temperature waste form production. Modifications were made to the dry blend composition to enable a 50% increase in waste concentration, thus allowing for a significant reduction in disposal volume and associated costs. Properties measurements showed that the advanced waste form can be produced using existing equipment and processes. Performance of the waste form was equivalent or better than the current baseline, with approximately double the amount of waste incorporation. The results demonstrate the feasibility of significantly accelerating low level waste immobilization missions across the DOE complex and at environmental remediation sites worldwide.

  1. Magnetic Phase Transition in Rare Earth Metal Holmium at Low Temperatures and High Pressures (United States)

    Thomas, Sarah; Uhoya, Walter; Wenger, Lowell; Vohra, Yogesh


    The heavy rare earth metal Holmium has been studied under high pressures and low temperatures using a designer diamond anvil cell and neutron diffraction using a Paris-Edinburgh Cell at the Spallation Neutrons and Pressure (SNAP) Diffractometer. The electrical resistance measurement using designer diamond shows a change in slope at the Neel temperature as the temperature is lowered at high pressures. At atmospheric pressure TN=120 K and decreases with a slope of -4.7 K/GPa as pressure is increased, until reaching 9 GPa, at which pressure the magnetic ordering is lost. This correlates to the pressure at which there is a structural change from an hcp phase to an α-Sm structure. Neutron diffraction measurements made above and below the Neel temperature at increasing pressures show the reversibility of the change between the paramagnetic and antiferromagnetic states. The parameters of the low temperature incommensurate magnetic phase will be reported at various pressures.

  2. Temperature and Pressure Dependence of the Reaction S plus CS (+M) -> CS2 (+M)

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul; Troe, Juergen


    Experimental data for the unimolecular decomposition of CS2 from the literature are analyzed by unimolecular rate theory with the goal of obtaining rate constants for the reverse reaction S + CS (+M) -> CS2 (+M) over wide temperature and pressure ranges. The results constitute an important input...... for the kinetic modeling of CS2 oxidation. CS2 dissociation proceeds as a spin-forbidden process whose detailed properties are still not well understood. The role of the singlet triplet transition involved is discussed....

  3. Process for carrying out a chemical reaction with ionic liquid and carbon dioxide under pressure

    NARCIS (Netherlands)

    Kroon, M.C.; Shariati, A.; Florusse, L.J.; Peters, C.J.; Van Spronsen, J.; Witkamp, G.J.; Sheldon, R.A.; Gutkowski, K.I.


    The invention is directed to a process for carrying out a chemical reaction in an ionic liquid as solvent and CO2 as cosolvent, in which process reactants are reacted in a homogeneous phase at selected pressure and temperature to generate a reaction product at least containing an end-product of the

  4. Measuring and predicting head space pressure during retorting of thermally processed foods. (United States)

    Ghai, Gaurav; Teixeira, Arthur A; Welt, Bruce A; Goodrich-Schneider, Renee; Yang, Weihua; Almonacid, Sergio


    Traditional metal cans and glass jars have been the mainstay in thermally processed canned foods for more than a century, but are now sharing shelf space with increasingly popular flexible pouches and semi-rigid trays. These flexible packages lack the strength of metal cans and glass jars, and need greater control of external retort pressure during processing. Increasing internal package pressure without counter pressure causes volumetric expansion, putting excessive strain on package seals that may lead to serious container deformation and compromised seal integrity. The primary objective of this study was to measure internal pressure build-up within a rigid air-tight container (module) filled with various model food systems undergoing a retort process in which internal product temperature and pressure, along with external retort temperature and pressure, were measured and recorded at the same time. The pressure build-up in the module was compared with the external retort pressure to determine the pressure differential that would cause package distortion in the case of a flexible package system. The secondary objective was to develop mathematical models to predict these pressure profiles in response to known internal temperature and initial and boundary conditions for the case of the very simplest of model food systems (pure water and aqueous saline and sucrose solutions), followed by food systems of increasing compositional complexity (green beans in water and sweet peas in water). Results showed that error between measured and predicted pressures ranged from 2% to 4% for water, saline, and green beans, and 7% to 13% for sucrose solution and sweet peas.   Flexible packages have limited strength, and need more accurate and closer control of retort pressure during processing. The package becomes more flexible as it heats and might expand with increasing internal pressure that may cause serious deformation or rupture if not properly controlled and

  5. Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores. (United States)

    Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W


    The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. 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

  7. A smart high accuracy silicon piezoresistive pressure sensor temperature compensation system. (United States)

    Zhou, Guanwu; Zhao, Yulong; Guo, Fangfang; Xu, Wenju


    Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM) as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU) after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system's performance. The temperature compensation is solved in the interval from -40 to 85 °C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 × 10(-5)/°C and 29.5 × 10(-5)/°C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 × 10(-5)/°C and 2.1 × 10(-5)/°C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor.

  8. A Smart High Accuracy Silicon Piezoresistive Pressure Sensor Temperature Compensation System

    Directory of Open Access Journals (Sweden)

    Guanwu Zhou


    Full Text Available Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system’s performance. The temperature compensation is solved in the interval from −40 to 85 °C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 × 10−5/°C and 29.5 × 10−5/°C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 × 10−5/°C and 2.1 × 10−5/°C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor.

  9. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    Directory of Open Access Journals (Sweden)

    Rama B. Bhat


    Full Text Available Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA, thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40–60 µm and thick (about 2–3 mm films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated.

  10. Signal Processing Methods Monitor Cranial Pressure (United States)


    Dr. Norden Huang, of Goddard Space Flight Center, invented a set of algorithms (called the Hilbert-Huang Transform, or HHT) for analyzing nonlinear and nonstationary signals that developed into a user-friendly signal processing technology for analyzing time-varying processes. At an auction managed by Ocean Tomo Federal Services LLC, licenses of 10 U.S. patents and 1 domestic patent application related to HHT were sold to DynaDx Corporation, of Mountain View, California. DynaDx is now using the licensed NASA technology for medical diagnosis and prediction of brain blood flow-related problems, such as stroke, dementia, and traumatic brain injury.

  11. Acrylic resin water sorption under different pressure, temperature and time conditions

    Directory of Open Access Journals (Sweden)

    Rizzatti-Barbosa Célia Marisa


    Full Text Available The purpose of this work was to analyze water sorption by polymerized acrylic resins under different pressure, temperature and time treatments. A thermo-cured acrylic resin was used as the denture base (Classico Ltda. and ethylene glycol di-methacrylate as a cross-linking agent, with processing carried out in a water bath at 73 °C for nine hours. Forty-five samples were prepared following the criteria and dimensions of specification # 12 of the American Dental Association (ADA, using a matrix in the shape of a stainless steel disc with 50 ± 1 mm diameter and 0.5 ± 0.05 mm thickness. The control group samples were stored in distilled water for 30 days, while groups GII to GIX were placed in a polymerization device with adjustable pressure, time and temperature. An analysis of the variance of the results revealed the influence of different factors on water sorption only, with significant factors being temperature, time, pressure and the interaction between time and temperature. Other interactions exerted no significant influence on water sorption. Neither additional treatments nor the control group (GI showed any significant difference in comparison to the averages of other treatments.

  12. Temperature characteristics research of SOI pressure sensor based on asymmetric base region transistor (United States)

    Zhao, Xiaofeng; Li, Dandan; Yu, Yang; Wen, Dianzhong


    Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors ({R}1, {R}2, {R}3 and {R}4) locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator (SOI) wafer by micro electromechanical system (MEMS) technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity (TCS) for the sensor before and after temperature compensation are -1862 and -1067 ppm/°C, respectively. Through varying the ratio of the base region resistances {r}1 and {r}2, the TCS for the sensor with the compensation circuit is -127 ppm/°C. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor. Project supported by the National Natural Science Foundation of China (No. 61471159), the Natural Science Foundation of Heilongjiang Province (No. F201433), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (No. 2015018), and the Special Funds for Science and Technology Innovation Talents of Harbin in China (No. 2016RAXXJ016).

  13. Generation of low-temperature air plasma for food processing (United States)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya


    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  14. Temperature of the Central Processing Unit

    Directory of Open Access Journals (Sweden)

    Ivan Lavrov


    Full Text Available Heat is inevitably generated in the semiconductors during operation. Cooling in a computer, and in its main part – the Central Processing Unit (CPU, is crucial, allowing the proper functioning without overheating, malfunctioning, and damage. In order to estimate the temperature as a function of time, it is important to solve the differential equations describing the heat flow and to understand how it depends on the physical properties of the system. This project aims to answer these questions by considering a simplified model of the CPU + heat sink. A similarity with the electrical circuit and certain methods from electrical circuit analysis are discussed.

  15. Effect of Furnish on Temperature and Vapor Pressure Behavior in the Center of Mat Panels during Hot Pressing

    Directory of Open Access Journals (Sweden)

    Muhammad Navis Rofii


    Full Text Available Particleboard achieves its overall performance characteristics during hot pressing process. As this process is influenced by several factors, particularly temperature and pressure, it is very important to understand the behavior of both. This study investigates the effects of furnish materials on temperature and vapor pressure behavior inside particleboard mat panels during hot pressing. Strand type particles from hinoki and ring-flaker recycled wood particles were used as furnish for laboratory-scale particleboard panels with a target density of 0.76 g/cm³. Mat panels with a moisture content of about 10% were hot pressed at a platen temperature of 180°C and an initial pressure of 3 MPa until the mat center reached the same temperature as the platen. A press monitoring device (PressMAN Lite was used for detecting the temperature and vapor pressure change in the center of the mat panels. The study showed that the furnish type affected the temperature and vapor behavior inside the mat panels. Particleboard made of hinoki strand resulted in a longer plateau time, a higher plateau temperature and a higher gas pressure generated during hot pressing than those of ring-flaker recycled wood particles. Mixed board resulted in values between those of the two other furnish materials.

  16. Simulation of changes in temperature and pressure fields during high speed projectiles forming by explosion

    Directory of Open Access Journals (Sweden)

    Marković Miloš D.


    Full Text Available The Research in this paper considered the temperatures fields as the consequently influenced effects appeared by plastic deformation, in the explosively forming process aimed to design Explosively Formed Projectiles (henceforth EFP. As the special payloads of the missiles, used projectiles are packaged as the metal liners, joined with explosive charges, to design explosive propulsion effect. Their final form and velocity during shaping depend on distributed temperatures in explosively driven plastic deformation process. Developed simulation model consider forming process without metal cover of explosive charge, in aim to discover liner’s dynamical correlations of effective plastic strains and temperatures in the unconstrained detonation environment made by payload construction. The temperature fields of the liner’s copper material are considered in time, as the consequence of strain/stress displacements driven by explosion environmental thermodynamically fields of pressures and temperatures. Achieved final velocities and mass loses as the expected EFP performances are estimated regarding their dynamical shaping and thermal gradients behavior vs. effective plastic strains. Performances and parameters are presented vs. process time, numerically simulated by the Autodyne software package. [Projekat Ministarstva nauke Republike Srbije, br. III-47029

  17. Signal processing in urodynamics: towards high definition urethral pressure profilometry. (United States)

    Klünder, Mario; Sawodny, Oliver; Amend, Bastian; Ederer, Michael; Kelp, Alexandra; Sievert, Karl-Dietrich; Stenzl, Arnulf; Feuer, Ronny


    Urethral pressure profilometry (UPP) is used in the diagnosis of stress urinary incontinence (SUI) which is a significant medical, social, and economic problem. Low spatial pressure resolution, common occurrence of artifacts, and uncertainties in data location limit the diagnostic value of UPP. To overcome these limitations, high definition urethral pressure profilometry (HD-UPP) combining enhanced UPP hardware and signal processing algorithms has been developed. In this work, we present the different signal processing steps in HD-UPP and show experimental results from female minipigs. We use a special microtip catheter with high angular pressure resolution and an integrated inclination sensor. Signals from the catheter are filtered and time-correlated artifacts removed. A signal reconstruction algorithm processes pressure data into a detailed pressure image on the urethra's inside. Finally, the pressure distribution on the urethra's outside is calculated through deconvolution. A mathematical model of the urethra is contained in a point-spread-function (PSF) which is identified depending on geometric and material properties of the urethra. We additionally investigate the PSF's frequency response to determine the relevant frequency band for pressure information on the urinary sphincter. Experimental pressure data are spatially located and processed into high resolution pressure images. Artifacts are successfully removed from data without blurring other details. The pressure distribution on the urethra's outside is reconstructed and compared to the one on the inside. Finally, the pressure images are mapped onto the urethral geometry calculated from inclination and position data to provide an integrated image of pressure distribution, anatomical shape, and location. With its advanced sensing capabilities, the novel microtip catheter collects an unprecedented amount of urethral pressure data. Through sequential signal processing steps, physicians are provided with

  18. Visual Aid to Demonstrate Change of State and Gas Pressure with Temperature (United States)

    Ghaffari, Shahrokh


    Demonstrations are used in chemistry lectures to improve conceptual understanding by direct observation. The visual aid described here is designed to demonstrate the change in state of matter with the change of temperature and the change of pressure with temperature. Temperature is presented by the rate of airflow and pressure is presented by…

  19. 46 CFR 153.438 - Cargo pressure or temperature alarms required. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pressure or temperature alarms required. 153.438... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Temperature Control Systems § 153.438 Cargo pressure or temperature alarms required. (a...

  20. Regional cooling for reducing brain temperature and intracranial pressure. (United States)

    Forte, Luis Vicente; Peluso, Cássio Morano; Prandini, Mirto Nelso; Godoy, Roberto; Rojas, Salomon Soriano Ordinola


    To evaluate the effectiveness of regional cooling for reducing brain temperature (BrTe) and intracranial pressure (ICP) in patients where conventional clinical treatment has failed. Regional cooling was carried out using ice bags covering the area of the craniectomy (regional method) in 23 patients. The BrTe and ICP were determined using a fiber optic sensor. Thirteen patients (56.52%) were female. The ages ranged from 16 to 83 years (mean of 48.9). The mean APACHE II score was 25 points (11-35). The patients were submitted, on mean, to 61.7 hours (20-96) of regional cooling. There was a significant reduction in mean BrTe (p<0.0001--from 37.1 degrees C to 35.2 degrees C) and mean ICP (p=0.0001--from 28 mmHg to 13 mmHg). Our results suggest that mild brain hypothermia induced by regional cooling was effective in the control of ICP in patients who had previously undergone decompressive craniectomy.

  1. High-temperature-pressure polymerized resin-infiltrated ceramic networks. (United States)

    Nguyen, J F; Ruse, D; Phan, A C; Sadoun, M J


    The aim of this study was to produce composite blocks (CB) for CAD/CAM applications by high-temperature-pressure (HT/HP) polymerization of resin-infiltrated glass-ceramic networks. The effect of network sintering and the absence/presence of initiator was investigated. Mechanical properties were determined and compared with those of Paradigm MZ100 (3M ESPE) blocks and HT/HP polymerized experimental "classic" CB, in which the filler had been incorporated by conventional mixing. The networks were made from glass-ceramic powder (VITA Zahnfabrik) formed by slip casting and were either sintered or not. They were silanized, infiltrated by urethane dimethacrylate, with or without initiator, and polymerized under HT/HP (300 MPa, 180°C) to obtain resin-infiltrated glass-ceramic network (RIGCN) CB. HT/HP polymerized CB were also made from an experimental "classic" composite. Flexural strength (σf), fracture toughness (KIC), and Vickers hardness were determined and analyzed by one- or two-way analysis of variance (ANOVA), Scheffé multiple-means comparisons (α = 0.05), and Weibull statistics (for σf). Fractured surfaces were characterized with scanning electron microscopy. The mechanical properties of RIGCN CB were significantly higher. Sintering induced significant increases in σf and hardness, while the initiator significantly decreased hardness. The results suggested that RIGCN and HT/HP polymerization could be used to obtain CB with superior mechanical properties, suitable for CAD/CAM applications.

  2. 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

  3. Predicting monsoon rainfall and pressure indices from sea surface temperature

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.

    . Office, Brecknell, UK). Relationship between SST and pressure indices (change in sea level pressure from January to April at Darwin (DWPJ-A), difference in sea level pressure at Bombay between April and January (BMBPA-J); change in 500mb ridge position...

  4. Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger. (United States)

    Ma, Y; Barbano, D M


    Raw skim milk, with or without added CO2, was heated, held, and cooled in a small pilot-scale tubular heat exchanger (372 ml/min). The experiment was replicated twice, and, for each replication, milk was first carbonated at 0 to 1 degree C to contain 0 (control), 600, 1200, 1800, and 2400 ppm added CO2 using a continuous carbonation unit. After storage at 0 to 1 degree C, portions of milk at each CO2 concentration were heated to 40, 56, 72, and 80 degrees C, held at the desired temperature for 30 s (except 80 degrees C, holding 20 s) and cooled to 0 to 1 degree C. At each temperature, five pressures were applied: 69, 138, 207, 276, and 345 kPa. Pressure was controlled with a needle valve at the heat exchanger exit. Both the pressure gauge and pH probe were inline at the end of the holding section. Milk pH during heating depended on CO2 concentration, temperature, and pressure. During heating of milk without added CO2, pH decreased linearly as a function of increasing temperature but was independent of pressure. In general, the pH of milk with added CO2 decreased with increasing CO2 concentration and pressure. For milk with added CO2, at a fixed CO2 concentration, the effect of pressure on pH decrease was greater at a higher temperature. At a fixed temperature, the effect of pressure on pH decrease was greater for milk with a higher CO2 concentration. Thermal death of bacteria during pasteurization of milk without added CO2 is probably due not only to temperature but also to the decrease in pH that occurs during the process. Increasing milk CO2 concentration and pressure decreases the milk pH even further during heating and may further enhance the microbial killing power of pasteurization.

  5. Deep-Ocean Bottom Pressure and Temperature Sensors Report: Methods and Data. (United States)


    N , T., and N used for conversion of’ :" temperatura a b ...... > temperature counts, N to emperature in c .......... 37 Table 8.2 Pressure sensor ...7 -A19 911 DEEP-OCEAN BOTTOM PRESSURE AND TEMPERATURE SENSORS 1/2REPORT! METHODS AIND DA, (U) RHODE ISLAND UNIV NARRAGANSETT GRADUAT SCHOOL OF...11 ..,: 1 ., DIE FILE COPY -> DEEP-OCEAN BOTTOM PRESSURE Cn AND TEMPERATURE SENSORS REPORT: METHODS AND DATA by D. R. WATTS and H. KONTOYIANNIS ckis

  6. High-pressure powder x-ray diffraction experiments on Zn at low temperature

    CERN Document Server

    Takemura, K; Fujihisa, H; Kikegawa, T


    High-pressure powder x-ray diffraction experiments have been performed on Zn with a He-pressure medium at low temperature. When the sample was compressed in the He medium at low temperature, large nonhydrostaticity developed, yielding erroneous lattice parameters. On the other hand, when the pressure was changed at high temperatures, good hydrostaticity was maintained. No anomaly in the volume dependence of the c/a axial ratio has been found.

  7. Technology trends in high temperature pressure transducers: The impact of micromachining (United States)

    Mallon, Joseph R., Jr.


    This paper discusses the implications of micromachining technology on the development of high temperature pressure transducers. The introduction puts forth the thesis that micromachining will be the technology of choice for the next generation of extended temperature range pressure transducers. The term micromachining is defined, the technology is discussed and examples are presented. Several technologies for high temperature pressure transducers are discussed, including silicon on insulator, capacitive, optical, and vibrating element. Specific conclusions are presented along with recommendations for development of the technology.

  8. 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.

  9. Assessment of Fluctuation Patterns Similarity in Temperature and Vapor Pressure Using Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    A. Araghi


    Full Text Available Period and trend are two main effective and important factors in hydro-climatological time series and because of this importance, different methods have been introduced and applied to study of them, until now. Most of these methods are statistical basis and they are classified in the non-parametric tests. Wavelet transform is a mathematical based powerful method which has been widely used in signal processing and time series analysis in recent years. In this research, trend and main periodic patterns similarity in temperature and vapor pressure has been studied in Babolsar, Tehran and Shahroud synoptic stations during 55 years period (from 1956 to 2010, using wavelet method and the sequential Mann-Kendall trend test. The results show that long term fluctuation patterns in temperature and vapor pressure have more correlations in the arid and semi-arid climates, as well as short term oscillation patterns in temperature and vapor pressure in the humid climates, and these dominant periods increase with the aridity of region.

  10. Liquidus Phases of the Richardson H5 Chondrite at High Pressures and Temperatures (United States)

    Channon, M.; Garber, J.; Danielson, L. R.; Righter, K.


    Part of early mantle evolution may include a magma ocean, where core formation began before the proto-Earth reached half of its present radius. Temperatures were high and bombardment and accretion were still occurring, suggesting that the proto-Earth consisted of a core and an at least partially liquid mantle, the magma ocean. As the Earth accreted, pressure near the core increased and the magma ocean decreased in volume and became shallower as it began to cool and solidify. As crystals settled, or floated, the composition of the magma ocean could change significantly and begin to crystallize different minerals from the residual liquid. Therefore, the mantle may be stratified following the P-T phase diagram for the bulk silicate Earth. To understand mantle evolution, it is necessary to know liquidus phase relations at high pressures and temperatures. In order to model the evolution of the magma ocean, high pressure and temperature experiments have been conducted to simulate the crystallization process using a range of materials that most likely resemble the bulk composition of the early Earth.

  11. Inactivation of transmissible spongiform encephalopathy agents in food products by ultra high pressure-temperature treatment. (United States)

    Cardone, Franco; Brown, Paul; Meyer, Richard; Pocchiari, Maurizio


    Bovine spongiform encephalopathy (BSE) contamination of the human food chain most likely resulted from nervous system tissue in mechanically recovered meat used in the manufacture of processed meats. The availability of effective decontamination methods for products considered at risk for BSE or other transmissible spongiform encephalopathies (TSEs) would be an attractive safeguard to human health, but neither of the two proven inactivating methods, autoclaving or exposure to strong alkali or bleach, are applicable to foodstuffs. Ultra high pressure-temperature treatment of foods is an effective decontamination method that can reduce the pathogen load while keeping unaltered the nutritional and organoleptic properties of the product. The application of different combinations of high pressure-temperature pulses to meat products 'spiked' with the agents of TSEs can reduce the level of infectivity by 10(3) to 10(6) mean lethal doses (LD(50)) per gram of tissue. These data indicate that the high pressure-temperature treatment is a ready-to-use and feasible strategy to reduce the risk of TSEs transmission via contaminated meat products.

  12. Matrix free fiber reinforced polymeric composites via high-temperature high-pressure sintering (United States)

    Xu, Tao


    A novel manufacturing process called high-temperature high-pressure sintering was studied and explored. Solid fiber reinforced composites are produced by consolidating and compacting layers of polymeric fabrics near their melting temperature under high pressure. There is no need to use an additional matrix as a bonding material. Partial melting and recrystallization of the fibers effectively fuse the material together. The product is called a "matrix free" fiber reinforced composite and essentially a one-polymer composite in which the fiber and the matrix have the same chemical composition. Since the matrix is eliminated in the process, it is possible to achieve a high fiber volume fraction and light weight composite. Interfacial adhesion between fibers and matrix is very good due to the molecular continuity throughout the system and the material is thermally shapeable. Plain woven Spectra RTM cloth made of SpectraRTM fiber was used to comprehensively study the process. The intrinsic properties of the material demonstrate that matrix free SpectraRTM fiber reinforced composites have the potential to make ballistic shields such as body armor and helmets. The properties and structure of the original fiber and the cloth were carefully examined. Optimization of the processing conditions started with the probing of sintering temperatures by Differential Scanning Calorimetry. Coupled with the information from structural, morphological and mechanical investigations on the samples sintered at different processing conditions, the optimal processing windows were determined to ensure that the outstanding original properties of the fibers translate into high ballistic performance of the composites. Matrix free SpectraRTM composites exhibit excellent ballistic resistance in the V50 tests conducted by the US Army. In the research, process-structure-property relationship is established and correlations between various properties and structures are understood. Thorough knowledge is

  13. Coherent Raman measurements of polymer thin-film pressure and temperature during picosecond laser ablation (United States)

    Hare, David E.; Franken, Jens; Dlott, Dana D.


    Picosecond time-resolved coherent Raman spectroscopy (ps CARS) is used to study photothermal ablation, induced by 150 ps duration near-infrared optical pulses, of poly-(methyl methacrylate) (PMMA) thin films doped with a small amount of near-infrared absorbing dye. The pressure and temperature shifts of a PMMA transition at ≊808 cm-1 were calibrated in static P and T experiments. Dynamic frequency shifting of the PMMA transition is used to determine temperature and pressure in the ablating thin film, and to investigate the dynamics of fast thin-film volume expansion. When the ablation pulse intensity is varied, ps CARS measurements of T and P are shown to be consistent with the results of conventional measurements below threshold, but near and above threshold picosecond time scale data show noticeable differences. Picosecond time scale ablation involves solid-state shock waves, which are not produced by longer duration ablation pulses. A pressure jump, often several kbar, is produced when the film is heated faster than a characteristic hydrodynamic volume relaxation time τh. Pressure release occurs by shock rarefaction wave propagation. When the rarefaction wave reaches the substrate, a tensile force is exerted on the thin film, causing it to break away from the substrate. The pressure in the thin film at ablation threshold, Pabl≊0.5 GPa, is found to be generated by roughly equal contributions from shock and thermochemical polymer decomposition processes. Therefore the picosecond time scale ablation process is termed shock-assisted photothermal ablation. The value of Pabl is interpreted to be the nanosecond time scale dynamic tensile strength of the thin film under conditions of ultrafast heating. It is found to be about one order of magnitude greater than the static strength of PMMA.


    Directory of Open Access Journals (Sweden)



    Full Text Available The low fruit and vegetable consumption identified by the World Health Organization is a significant factor for adverse health consequences, like obesity and noncommunicable diseases. In the worldwide effort of boosting fruit and vegetable consumption to at least five servings of fruits and vegetables per day (5-A-Day, healthy, mildly sweet and salty dried crunchy vegetable snacks can add up increasing attractiveness of vegetables among youngsters. The objectives of this research were to obtain sweet and salty dried parsnip snacks, pretreated with concentrated whey (CW and concentrated hydrolyzed whey (HW, to study the influence of osmotic pressure and temperature (45, 55 and 65 °C on the convective drying process and to estimate the kinetic parameters (diffusion coefficients, activation energy of parsnip drying. Nonlinear regression models were applied to estimate the drying parameters based on Henderson - Pabis equations. Results have shown that the activation energy required during drying by the chips treated with HW (23.89 kJ·mol-1 and CW (20.06 kJ·mol-1 is lower than in the reference sample (31.02 kJ·mol-1. Moreover, these represents a smart valorization of a by product from dairy industry rich in valuable minerals, proteins and sugars in the veggie industry.

  15. Strawberry puree processed by thermal, high pressure, or power ultrasound: Process energy requirements and quality modeling during storage. (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm


    Strawberry puree was processed for 15 min using thermal (65 ℃), high-pressure processing (600 MPa, 48 ℃), and ultrasound (24 kHz, 1.3 W/g, 33 ℃). These conditions were selected based on similar polyphenoloxidase inactivation (11%-18%). The specific energies required for the above-mentioned thermal, high-pressure processing, and power ultrasound processes were 240, 291, and 1233 kJ/kg, respectively. Then, the processed strawberry was stored at 3 ℃ and room temperature for 30 days. The constant pH (3.38±0.03) and soluble solids content (9.03 ± 0.25°Brix) during storage indicated a microbiological stability. Polyphenoloxidase did not reactivate during storage. The high-pressure processing and ultrasound treatments retained the antioxidant activity (70%-74%) better than the thermal process (60%), and high-pressure processing was the best treatment after 30 days of ambient storage to preserve antioxidant activity. Puree treated with ultrasound presented more color retention after processing and after ambient storage than the other preservation methods. For the three treatments, the changes of antioxidant activity and total color difference during storage were described by the fractional conversion model with rate constants k ranging between 0.03-0.09 and 0.06-0.22 day - 1, respectively. In resume, high-pressure processing and thermal processes required much less energy than ultrasound for the same polyphenoloxidase inactivation in strawberry. While high-pressure processing retained better the antioxidant activity of the strawberry puree during storage, the ultrasound treatment was better in terms of color retention.

  16. Adaptation to fluctuating temperatures in an RNA virus is driven by the most stringent selective pressure.

    Directory of Open Access Journals (Sweden)

    María Arribas

    Full Text Available The frequency of change in the selective pressures is one of the main factors driving evolution. It is generally accepted that constant environments select specialist organisms whereas changing environments favour generalists. The particular outcome achieved in either case also depends on the relative strength of the selective pressures and on the fitness costs of mutations across environments. RNA viruses are characterized by their high genetic diversity, which provides fast adaptation to environmental changes and helps them evade most antiviral treatments. Therefore, the study of the adaptive possibilities of RNA viruses is highly relevant for both basic and applied research. In this study we have evolved an RNA virus, the bacteriophage Qβ, under three different temperatures that either were kept constant or alternated periodically. The populations obtained were analyzed at the phenotypic and the genotypic level to characterize the evolutionary process followed by the virus in each case and the amount of convergent genetic changes attained. Finally, we also investigated the influence of the pre-existent genetic diversity on adaptation to high temperature. The main conclusions that arise from our results are: i under periodically changing temperature conditions, evolution of bacteriophage Qβ is driven by the most stringent selective pressure, ii there is a high degree of evolutionary convergence between replicated populations and also among populations evolved at different temperatures, iii there are mutations specific of a particular condition, and iv adaptation to high temperatures in populations differing in their pre-existent genetic diversity takes place through the selection of a common set of mutations.

  17. Unraveling the pressure effect on nucleation processes of amyloidogenic proteins. (United States)

    Gruzielanek, Stefan; Zhai, Yong; Winter, Roland


    The influence of pressure on the nucleation rate of insulin under fibril-forming conditions was studied and subsequently analysed using classical nucleation theory. The aim was a better understanding and quantification of the influence of pressure on protein aggregation/fibrillation reactions. The application of pressure has a drastic accelerating effect on the nucleation and growth process of insulin fibrils. We show that this effect arises from a volume decrease upon nucleus formation, due to formation of a less hydrated and more compact transition state that can be quantified extending nucleation theory by a pressure-volume term. Conversely, the absolute values of the lag time and the critical size of the nucleus cannot be satisfactorily described by the classical nucleation theory, which might be due to the presence of secondary effects, such as parallel aggregation pathways or fragmentation processes.

  18. Process characteristics of laser beam welding at reduced ambient pressure (United States)

    Börner, Christian; Krüssel, Thomas; Dilger, Klaus


    This paper describes the idea of using a similar vacuum necessary for electron beam welding also for welding with a solid-state laser. While for electron beam welding a fine vacuum is required for the process, with laser beam welding the pressure can be varied as an additional process parameter in order to influence the process result. Test results show that by a reduction of the ambient pressure the metal vapor plume is suppressed and consequently the spattering decreases. Plume and spatters disappear completely at a pressure reduction to p = 10 hPa and below. This enables quality of weldings with the solid-state laser which even with CO2 lasers are only difficult to realize. The quality of these weld seams is comparable to electron beam weldings. In addition, further beneficial properties arise in the quality of the weld seam. With the same process parameters but reduced ambient pressure, the reduction of the pressure effects an increase of the penetration depth and a distinctive modification of the seam geometry. Mild steel plates with a thickness of 10 mm have been successfully welded with a laser power of PL = 6000 W and a feed rate of vW = 2.0 m/min, with a remarkable seam quality without any irregularities. Another advantage of welding with the laser at reduced pressure is the possibility of avoiding a sagging of the seam during welding of thick sheets. Despite excessive energy and power, no geometric irregularities are identified in the cross section. Under atmospheric pressure, the high excess of power would lead to an intense seam collapse. On sheets with thicknesses of 3 mm, the notches occurring by penetration welding can also be avoided by applying reduced pressure.

  19. Coupling of temperature with pressure induced initial decomposition ...

    Indian Academy of Sciences (India)

    The pressure effects on the initial decomposition stepsand initially generated products on PETN and NTO were very different. PETN was triggered by C-H... O intermolecular hydrogen transfer. The initial decomposition mechanism was independent of the pressure. ForNTO, two different initial decomposition mechanisms ...

  20. An Ultrasound-Based Liquid Pressure Measurement Method in Small Diameter Pipelines Considering the Installation and Temperature

    Directory of Open Access Journals (Sweden)

    Xue Li


    Full Text Available Liquid pressure is a key parameter for detecting and judging faults in hydraulic mechanisms, but traditional measurement methods have many deficiencies. An effective non-intrusive method using an ultrasound-based technique to measure liquid pressure in small diameter (less than 15 mm pipelines is presented in this paper. The proposed method is based on the principle that the transmission speed of an ultrasonic wave in a Kneser liquid correlates with liquid pressure. Liquid pressure was calculated using the variation of ultrasonic propagation time in a liquid under different pressures: 0 Pa and X Pa. In this research the time difference was obtained by an electrical processing approach and was accurately measured to the nanosecond level through a high-resolution time measurement module. Because installation differences and liquid temperatures could influence the measurement accuracy, a special type of circuit called automatic gain control (AGC circuit and a new back propagation network (BPN model accounting for liquid temperature were employed to improve the measurement results. The corresponding pressure values were finally obtained by utilizing the relationship between time difference, transient temperature and liquid pressure. An experimental pressure measurement platform was built and the experimental results confirm that the proposed method has good measurement accuracy.

  1. Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 °C (United States)

    Dureja, A. K.; Sinha, S. K.; Srivastava, Ankit; Sinha, R. K.; Chakravartty, J. K.; Seshu, P.; Pawaskar, D. N.


    Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 °C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce's correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.

  2. iron phase control during pressure leaching at elevated temperature (United States)

    Fleuriault, Camille

    Iron is a common contaminant encountered in most metal recovery operations, and particularly hydrometallurgical processes. For example, the Hematite Process uses autoclaves to precipitate iron oxide out of the leaching solution, while other metals are solubilized for further hydrometallurgical processing. In some cases, Basic Iron Sulfate (BIS) forms in place of hematite. The presence of BIS is unwanted in the autoclave discharge because it diminishes recovery and causes environmental matters. The focus of this master thesis is on the various iron phases forming during the pressure oxidation of sulfates. Artificial leaching solutions were produced from CuSO4, FeSO4 and H2SO4 in an attempt to recreate the matrix composition and conditions used for copper sulfides autoclaving. The following factors were investigated in order to determine which conditions hinder the formation of BIS: initial free acidity (5 -- 98 g/L), initial copper concentration (12.7 -- 63.5 g/L), initial iron concentration (16.7 -- 30.7 g/L) and initial iron oxidation state. There were three solid species formed in the autoclave: hematite, BIS and hydronium jarosite. The results show that free acid is the main factor influencing the composition of the residue. At an initial concentration of 22.3 g/L iron and no copper added, the upper limit for iron oxide formation is 41 g/L H2SO4. The increase of BIS content in the residue is not gradual and occurs over a change of a few grams per liter around the aforementioned limit. Increasing copper sulfate concentration in the solution hinders the formation of BIS. At 63.5g/L copper, the upper free acidity limit is increased to 61g/L. This effect seems to be related to the buffering action of copper sulfate, decreasing the overall acid concentration and thus extending the stability range of hematite. The effect of varying iron concentration on the precipitate chemistry is unclear. At high iron levels, the only noticeable effect was the inhibition of jarosite

  3. High Throughput Atomic Layer Deposition Processes: High Pressure Operations, New Reactor Designs, and Novel Metal Processing (United States)

    Mousa, MoatazBellah Mahmoud

    Atomic Layer Deposition (ALD) is a vapor phase nano-coating process that deposits very uniform and conformal thin film materials with sub-angstrom level thickness control on various substrates. These unique properties made ALD a platform technology for numerous products and applications. However, most of these applications are limited to the lab scale due to the low process throughput relative to the other deposition techniques, which hinders its industrial adoption. In addition to the low throughput, the process development for certain applications usually faces other obstacles, such as: a required new processing mode (e.g., batch vs continuous) or process conditions (e.g., low temperature), absence of an appropriate reactor design for a specific substrate and sometimes the lack of a suitable chemistry. This dissertation studies different aspects of ALD process development for prospect applications in the semiconductor, textiles, and battery industries, as well as novel organic-inorganic hybrid materials. The investigation of a high pressure, low temperature ALD process for metal oxides deposition using multiple process chemistry revealed the vital importance of the gas velocity over the substrate to achieve fast depositions at these challenging processing conditions. Also in this work, two unique high throughput ALD reactor designs are reported. The first is a continuous roll-to-roll ALD reactor for ultra-fast coatings on porous, flexible substrates with very high surface area. While the second reactor is an ALD delivery head that allows for in loco ALD coatings that can be executed under ambient conditions (even outdoors) on large surfaces while still maintaining very high deposition rates. As a proof of concept, part of a parked automobile window was coated using the ALD delivery head. Another process development shown herein is the improvement achieved in the selective synthesis of organic-inorganic materials using an ALD based process called sequential vapor

  4. 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.

  5. An Annular Mechanical Temperature Compensation Structure for Gas-Sealed Capacitive Pressure Sensor (United States)

    Hao, Xiuchun; Jiang, Yonggang; Takao, Hidekuni; Maenaka, Kazusuke; Higuchi, Kohei


    A novel gas-sealed capacitive pressure sensor with a temperature compensation structure is reported. The pressure sensor is sealed by Au-Au diffusion bonding under a nitrogen ambient with a pressure of 100 kPa and integrated with a platinum resistor-based temperature sensor for human activity monitoring applications. The capacitance-pressure and capacitance-temperature characteristics of the gas-sealed capacitive pressure sensor without temperature compensation structure are calculated. It is found by simulation that a ring-shaped structure on the diaphragm of the pressure sensor can mechanically suppress the thermal expansion effect of the sealed gas in the cavity. Pressure sensors without/with temperature compensation structures are fabricated and measured. Through measured results, it is verified that the calculation model is accurate. Using the compensation structures with a 900 μm inner radius, the measured temperature coefficient is much reduced as compared to that of the pressure sensor without compensation. The sensitivities of the pressure sensor before and after compensation are almost the same in the pressure range from 80 kPa to 100 kPa. PMID:22969385

  6. Alcohol electrooxidation at Pt and Pt-Ru sputtered electrodes under elevated temperature and pressurized conditions (United States)

    Umeda, Minoru; Sugii, Hiromasa; Uchida, Isamu


    The electrooxidation properties of methanol and 2-propanol, which are both promising candidates for direct alcohol fuel cells (DAFCs), have been studied under elevated temperature and pressurized conditions. Sputter-deposited Pt and Pt-Ru electrodes were well-characterized and utilized for the electrochemical measurement of the alcohol oxidation at 25-100 °C. The Pt electrode prepared at 600 °C had a flat surface, and the Pt-Ru formed an alloy. The electrochemical measurements were carried out in a gas-tight cell under elevated temperature, which accompanies the pressurized condition. This is a representative example of the DAFC rising temperature operation. As a result, at 25 °C, the onset potential of the 2-propanol oxidation is about 400 mV more negative than that of the methanol oxidation, and current density of the 2-propanol oxidation exceeds that of the methanol oxidation. Conversely, at 100 °C, the methanol oxidation current density overcomes that of 2-propanol, and the onset potentials of the two are almost the same. The highest current density for the methanol oxidation is obtained at the Pt:Ru = 50:50 electrode, whereas at the Pt:Ru = 35:65 for the 2-propanol oxidation. A Tafel plot analysis was employed to investigate the reaction mechanism. For the methanol oxidation, the number of electrons transferred during the rate-determining process is estimated to be 1 at 25 °C and 2 at 100 °C. This suggests that the methanol reaction mechanism differs at 25 and 100 °C. In contrast, the rate-determining process of the 2-propanol oxidation at 25 and 100 °C was expected to be 1-electron transfer which accompanies the proton-elimination reaction to produce acetone. Consequently, it is deduced that methanol and 2-propanol have an advantage under the rising temperature and room temperature operation, respectively.

  7. Anomalous dependence of the heat capacity of supercooled water on pressure and temperature

    Directory of Open Access Journals (Sweden)

    I.A. Stepanov


    Full Text Available In some papers, dependences of the isobaric heat capacity of water versus pressure and temperature were obtained. It is shown that these dependences contradict both the dependence of heat capacity on temperature for supercooled water, and an important thermodynamic equation for the dependence of heat capacity on pressure. A possible explanation for this contradiction is proposed.

  8. Numerical analysis of accidental hydrogen releases from high pressure storage at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, Daniele; Baraldi, Daniele


    ) and temperatures (down to 20 K), e.g. cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33 K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types...

  9. High-temperature pressure sensors with strain gauges based on silicon whiskers


    Druzhinin A. A.; Kutrakov A. P.; Maryamova I. I.


    Studies aimed at the creating of piezoresistive pressure sensors based on silicon whiskers, operating at high temperatures were carried out. Using the glass adhesive for strain gauges mounting on spring elements of covar alloy gave the possibility to elevate the sensor’s operating temperature range. Several modifications of pressure sensors based on the proposed strain-unit design were developed.

  10. High-temperature pressure sensors with strain gauges based on silicon whiskers

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.


    Full Text Available Studies aimed at the creating of piezoresistive pressure sensors based on silicon whiskers, operating at high temperatures were carried out. Using the glass adhesive for strain gauges mounting on spring elements of covar alloy gave the possibility to elevate the sensor’s operating temperature range. Several modifications of pressure sensors based on the proposed strain-unit design were developed.

  11. Path-integral simulation of ice VII: Pressure and temperature effects

    CERN Document Server

    Herrero, Carlos P


    Effects of pressure and temperature on structural and thermodynamic properties of ice VII have been studied by using path-integral molecular dynamics (PIMD) simulations. Temperatures between 25 and 450 K, as well as pressures up to 12 GPa were considered. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. We analyze the pressure dependence of the molar volume, bulk modulus, interatomic distances, kinetic energy, and atomic delocalization at various temperatures. Results of PIMD simulations are compared with those derived from a quasi-harmonic approximation (QHA) of vibrational modes, which helps to assess the importance of anharmonic effects, as well as the influence of the different modes on the properties of ice VII. The accuracy of the QHA for describing this high-pressure phase decreases for rising temperature, but this approximation becomes more reliable as pressure grows, since anharmonicity becomes less relevant. Comparisons with low-pressure cubic ice ...

  12. Factors Affecting Bacterial Inactivation during High Hydrostatic Pressure Processing of Foods: A Review. (United States)

    Syed, Qamar-Abbas; Buffa, Martin; Guamis, Buenaventura; Saldo, Jordi


    Although, the High Hydrostatic Pressure (HHP) technology has been gaining gradual popularity in food industry since last two decades, intensive research is needed to explore the missing information. Bacterial inactivation in food by using HHP applications can be enhanced by getting deeper insights of the process. Some of these aspects have been already studied in detail (like pressure, time, and temperature, etc.), while some others still need to be investigated in more details (like pH, rates of compression, and decompression, etc.). Selection of process parameters is mainly dependent on type of matrix and target bacteria. This intensive review provides comprehensive information about the variety of aspects that can determine the bacterial inactivation potential of HHP process indicating the fields of future research on this subject including pH shifts of the pressure treated samples and critical limits of compression and decompression rates to accelerate the process efficacy.

  13. High-pressure high-temperature phase diagram of organic crystal paracetamol (United States)

    Smith, Spencer J.; Montgomery, Jeffrey M.; Vohra, Yogesh K.


    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol.

  14. Influence of process temperature on AZ91 matrix microstructure of composites with aluminosilicate glass cenospheres


    J. Kamieniak; A. Żydek; K.N. Braszczyńska-Malik


    AZ91 magnesium alloy matrix composites with aluminosilicate glass cenospheres were fabricated successfully by the pressure infiltration method. Different parameters of the fabrication process, such as temperature of the mould and temperature of cenospheres were used. Influence of the temperature variation of particular parameters on the microstructure has been investigated. The microstructure of AZ91 magnesium alloy and fabricated composites have been investigated by light microscopy (LM) and...

  15. Effect of working pressure and annealing temperature on ...

    Indian Academy of Sciences (India)

    In this paper, Ba0.6Sr0.4TiO3 thin film has been deposited on the SiO2/Si substrate by the pulsed laser deposition (PLD) technique at three different oxygen working pressures of 100, 220 and 350 mTorr. Then the deposited thin films at 100 mTorr oxygen pressure were annealed for 50 min in oxygen ambient at three ...

  16. Hydrodynamic pressure processing: Impact on the quality attributes of fresh and further-processed meat products (United States)

    This book chapter reviews hydrodynamic pressure processing (HDP) as an innovative, postharvest technology for enhancing the quality attributes of fresh and further-processed meat products. A variety of meat products have been tested for their response to the high pressure shockwaves of HDP. The st...

  17. Stochastic processes in postural center-of-pressure profiles. (United States)

    Newell, K M; Slobounov, S M; Slobounova, E S; Molenaar, P C


    The stochastic processes of postural center-of-pressure profiles were examined in 3- and 5-year-old children, young adult students (mean 20 years), and an elderly age group (mean 67 years). Subjects stood still in an upright bipedal stance on a force platform under vision and nonvision conditions. The time evolutionary properties of the center-of-pressure dynamic were examined using basic stochastic process models. The amount of motion of the center of pressure decreased with increments of age from 3 to 5 years to young adult but increased again in the elderly age group. The availability of vision decreased the amount of motion of the center of pressure in all groups except the 3-year-old group, where there was less motion of the center of pressure with no vision. The stochastic properties of the center-of-pressure dynamic were assessed using both a two-process, random-walk model of Collins and De Luca and an Ornstein-Uhlenbeck model that is linear and has displacement governed only by a single stiffness term in the random walk. The two-process open- and closed-loop model accounted for about 96% and the Ornstein-Uhlenbeck model 92% of the variance of the diffusion term. Diffusion parameters in both models showed that the data were correlated and that they varied with age in a fashion consistent with developmental accounts of the changing regulation of the degrees of freedom in action. The findings suggest that it is premature to consider the trajectory of the center-of-pressure as a two-process, open- and closed-loop random-walk model given that: (a) the linear Ornstein-Uhlenbeck dynamic equation with only two parameters accommodates almost as much of the variance of the random walk; and (b) the linkage of a discontinuity in the diffusion process with the transition of open- to closed-loop processes is poorly founded. It appears that the nature of the stochastic properties of the random walk of the center-of-pressure trajectory in quiet, upright standing remains to

  18. Recent Advances in Food Processing Using High Hydrostatic Pressure Technology. (United States)

    Wang, Chung-Yi; Huang, Hsiao-Wen; Hsu, Chiao-Ping; Yang, Binghuei Barry


    High hydrostatic pressure is an emerging non-thermal technology that can achieve the same standards of food safety as those of heat pasteurization and meet consumer requirements for fresher tasting, minimally processed foods. Applying high-pressure processing can inactivate pathogenic and spoilage microorganisms and enzymes, as well as modify structures with little or no effects on the nutritional and sensory quality of foods. The U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) have approved the use of high-pressure processing (HPP), which is a reliable technological alternative to conventional heat pasteurization in food-processing procedures. This paper presents the current applications of HPP in processing fruits, vegetables, meats, seafood, dairy, and egg products; such applications include the combination of pressure and biopreservation to generate specific characteristics in certain products. In addition, this paper describes recent findings on the microbiological, chemical, and molecular aspects of HPP technology used in commercial and research applications.

  19. Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea


    Hubert Bonnefond; Ghjuvan Grimaud; Judith Rumin; Gaël Bougaran; Amélie Talec; Manon Gachelin; Marc Boutoute; Eric Pruvost; Olivier Bernard; Antoine Sciandra


    International audience; Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submi...

  20. A novel dual-functional MEMS sensor integrating both pressure and temperature units

    Energy Technology Data Exchange (ETDEWEB)

    Chen Tao; Zhang Zhaohua; Ren Tianling; Miao Gujin; Zhou Changjian; Lin Huiwang; Liu Litian, E-mail: [National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)


    This paper proposes a novel miniature dual-functional sensor integrating both pressure and temperature sensitive units on a single chip. The device wafer of SOI is used as a pizeoresistive diaphragm which features excellent consistency in thickness. The conventional anisotropic wet etching has been abandoned, while ICP etching has been employed to etch out the reference cave to minimize the area of individual device in the way that the 57.4{sup 0} slope has been eliminated. As a result, the average cost of the single chip is reduced. Two PN junctions with constant ratio of the areas of depletion regions have also been integrated on the same chip to serve as a temperature sensor, and each PN junction shows high linearity over -40 to 100 {sup 0}C and low power consumption. The iron implanting process for PN junction is exactly compatible with the piezoresistor, with no additional expenditure. The pressure sensitivity is 86 mV/MPa, while temperature sensitivity is 1.43 mV/{sup 0}C, both complying with the design objective.

  1. Application of multi-pass high pressure homogenization under variable temperature regimes to induce autolysis of wine yeasts. (United States)

    Comuzzo, Piergiorgio; Calligaris, Sonia; Iacumin, Lucilla; Ginaldi, Federica; Voce, Sabrina; Zironi, Roberto


    The effects of the number of passes and processing temperature management (controlled vs. uncontrolled) were investigated during high pressure homogenization-induced autolysis of Saccharomyces bayanus wine yeasts, treated at 150MPa. Both variables were able to affect cell viability, and the release of soluble molecules (free amino acids, proteins and glucidic colloids), but the effect of temperature was more important. S. bayanus cells were completely inactivated in 10 passes without temperature control (corresponding to a processing temperature of 75°C). The two processing variables also affected the volatile composition of the autolysates produced: higher temperatures led to a lower concentration of volatile compounds. The management of the operating conditions may allow the compositional characteristics of the products to be modulated, making them suitable for different winemaking applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Thermoset recycling via high-pressure high-temperature sintering: Revisiting the effect of interchange chemistry (United States)

    Morin, Jeremy Edward

    In 1844 Charles Goodyear obtained U.S. Patent #3,633 for his "Gum Elastic Composition". In a published circular, which describes his patent for the sulfur vulcanization of gum elastic composition, he stated: "No degree of heat, without blaze, can melt it (rubber)... It resists the most powerful chemical reagents. Aquafortis (nitric acid), sulphuric acid, essential and common oils, turpentine and other solvents... ..." Goodyear's sulfur vulcanization of rubber fueled much of the industrial revolution and made transportation possible, as it exists today. In doing so, Goodyear created one of the most difficult materials to recycle. Rubber will not melt, dissolve, or lend itself to the usual methods of chemical decomposition. Ironically, Goodyear recognized this problem and in 1853 he patented the process of adding ground rubber to virgin material, now currently known as regrind blending. Today, scrap tires represent one of the most serious sources of pollution in the world. Studies estimate that there are roughly 2 billion scrap tires in U.S. landfills and more are being added at a rate of over 273 million tires per year. Current methods of recycling waste tires are crude, ineffective, and use rubber powder as a low cost filler instead of a new rubber. The groundwork for a very simple and effective method of producing high-quality rubber goods using 100% scrap rubber was discovered in 1944 by A. V. Tobolsky et al. This application, however, was not recognized until recently in our laboratory. The process as studied to date represents a method of creating quality, high-value added rubber goods with nothing other than heat and pressure. High pressure is required to obtain a void-free compaction of the rubber particles by forcing all of the free surfaces into intimate contact. High temperature then activates the chemical rearrangement, scission, and reformation of the chemical bonds thus providing new bridges between the once fractured interfaces. This occurs both within

  3. Transport Processes in High Temperature QCD Plasmas (United States)

    Hong, Juhee

    The transport properties of high temperature QCD plasmas can be described by kinetic theory based on the Boltzmann equation. At a leading-log approximation, the Boltzmann equation is reformulated as a Fokker-Planck equation. First, we compute the spectral densities of Tµν and Jµ by perturbing the system with weak gravitational and electromagnetic fields. The spectral densities exhibit a smooth transition from free-streaming quasi-particles to hydrodynamics. This transition is analyzed with hydrodynamics and diffusion equation up to second order. We determine all of the first and second order transport coefficients which characterize the linear response in the hydrodynamic regime. Second, we simulate the wake of a heavy quark moving through the plasmas. At long distances, the energy density and flux distributions show sound waves and a diffusion wake. The kinetic theory calculations based on the Boltzmann equation at weak coupling are compared to the strong coupling results given by the AdS/CFT correspondence. By using the hard-thermal-loop effective theory, we determine the photon emission rate at next-to-leading order (NLO), i.e., at order g2mD /T. There are three mechanisms which contribute to the leading-order photon emission: (2 ↔ 2) elastic scatterings, (1 ↔ 2) collinear bremsstrahlung, and (1 ↔ 1) quark-photon conversion due to soft fermion exchange. At NLO, these three mechanisms are not completely independent. When the transverse momentum between quark and photon becomes soft, the Compton scattering with a soft gluon reduces to wide-angle bremsstrahlung. Similarly, bremsstrahlung reduces to the quark-photon conversion process when the photon carries most of the incoming momentum. Therefore, the rates should be matched to determine the wide-angle NLO correction. Collinear bremsstrahlung can be accounted for by solving an integral equation which corresponds to summing ladder diagrams. With O(g) corrections in the collision kernel and the asymptotic

  4. Macroscopic Expressions of Molecular Adiabatic Compressibility of Methyl and Ethyl Caprate under High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Fuxi Shi


    Full Text Available The molecular compressibility, which is a macroscopic quantity to reveal the microcompressibility by additivity of molecular constitutions, is considered as a fixed value for specific organic liquids. In this study, we introduced two calculated expressions of molecular adiabatic compressibility to demonstrate its pressure and temperature dependency. The first one was developed from Wada’s constant expression based on experimental data of density and sound velocity. Secondly, by introducing the 2D fitting expressions and their partial derivative of pressure and temperature, molecular compressibility dependency was analyzed further, and a 3D fitting expression was obtained from the calculated data of the first one. The third was derived with introducing the pressure and temperature correction factors based on analogy to Lennard-Jones potential function and energy equipartition theorem. In wide range of temperatures (293pressures (0.1

    process for diesel engines, the calculated results consistency of three formulas demonstrated their effectiveness with the maximum 0.5384% OARD; meanwhile, the dependency on pressure and temperature of molecular compressibility was certified.

  5. Experimental Air Pressure Tank Systems for Process Control Education (United States)

    Long, Christopher E.; Holland, Charles E.; Gatzke, Edward P.


    In process control education, particularly in the field of chemical engineering, there is an inherent need for industrially relevant hands-on apparatuses that enable one to bridge the gap between the theoretical content of coursework and real-world applications. At the University of South Carolina, two experimental air-pressure tank systems have…

  6. Comparison of pressure-driven membrane processes and traditional ...

    African Journals Online (AJOL)

    Due to the policy of many governments of encouraging the use of alternative water sources instead of groundwater, there is a clear need for enhanced water purification systems such as pressure-driven membrane processes. In this article a comparison is made between drinking water production from surface water using ...

  7. Waste Feed Delivery Purex Process Connector Design Pressure

    Energy Technology Data Exchange (ETDEWEB)



    The pressure retaining capability of the PUREX process connector is documented. A context is provided for the connector's current use within existing Projects. Previous testing and structural analyses campaigns are outlined. The deficient condition of the current inventory of connectors and assembly wrenches is highlighted. A brief history of the connector is provided. A bibliography of pertinent references is included.

  8. Translational, rotational and vibrational temperatures of a gliding arc discharge at atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas


    Gliding arc discharges have generally been used to generate non-equilibrium plasma at atmospheric pressure. Temperature distributions of a gliding arc are of great interest both for fundamental plasma research and for practical applications. In the presented studies, translational, rotational...... and vibrational temperatures of a gliding arc generated at atmospheric pressure air are investigated. Translational temperatures (about 1100 K) were measured by laser-induced Rayleigh scattering, and two-dimensional temperature imaging was performed. Rotational and vibrational temperatures (about 3600 K and 6700...

  9. The effect of pressure on the Curie temperature in Fe-Ni Invar mechanical alloys

    CERN Document Server

    Wei, S; Zach, R; Matsushita, M; Takahashi, A; Inoue, H; Ono, F; Maeta, H; Iwase, A; Endo, S


    Measurements of the temperature dependence of the AC susceptibility were made for Fe-Ni Invar mechanical alloys under hydrostatic pressures up to 1.5 GPa. The Curie temperatures decreased linearly with pressure. The rate of decrease became larger for specimens annealed at higher temperatures. The temperature of annealing after ball milling has been directly related to the extent of the chemical concentration fluctuation, and the extent becomes smaller for specimens annealed at higher temperature. This tendency can be explained by assuming a Gaussian distribution function.

  10. The analysis of energy efficiency in water electrolysis under high temperature and high pressure (United States)

    Hourng, L. W.; Tsai, T. T.; Lin, M. Y.


    This paper aims to analyze the energy efficiency of water electrolysis under high pressure and high temperature conditions. The effects of temperature and pressure on four different kinds of reaction mechanisms, namely, reversible voltage, activation polarization, ohmic polarization, and concentration polarization, are investigated in details. Results show that the ohmic and concentration over-potentials are increased as temperature is increased, however, the reversible and activation over-potentials are decreased as temperature is increased. Therefore, the net efficiency is enhanced as temperature is increased. The efficiency of water electrolysis at 350°C/100 bars is increased about 17%, compared with that at 80°C/1bar.

  11. Invited article: High-pressure techniques for condensed matter physics at low temperature. (United States)

    Feng, Yejun; Jaramillo, R; Wang, Jiyang; Ren, Yang; Rosenbaum, T F


    Condensed matter experiments at high pressure accentuate the need for accurate pressure scales over a broad range of temperatures, as well as placing a premium on a homogeneous pressure environment. However, challenges remain in diamond anvil cell technology, including both the quality of various pressure transmitting media and the accuracy of secondary pressure scales at low temperature. We directly calibrate the ruby fluorescence R1 line shift with pressure at T=4.5 K using high-resolution x-ray powder diffraction measurements of the silver lattice constant and its known equation of state up to P=16 GPa. Our results reveal a ruby pressure scale at low temperatures that differs by 6% from the best available ruby scale at room T. We also use ruby fluorescence to characterize the pressure inhomogeneity and anisotropy in two representative and commonly used pressure media, helium and methanol:ethanol 4:1, under the same preparation conditions for pressures up to 20 GPa at T=5 K. Contrary to the accepted wisdom, both media show equal levels of pressure inhomogeneity measured over the same area, with a consistent DeltaP/P per unit area of +/-1.8 %/(10(4) microm(2)) from 0 to 20 GPa. The helium medium shows an essentially constant deviatoric stress of 0.021+/-0.011 GPa up to 16 GPa, while the methanol:ethanol mixture shows a similar level of anisotropy up to 10 GPa, above which the anisotropy increases. The quality of both pressure media is further examined under the more stringent requirements of single crystal x-ray diffraction at cryogenic temperature. For such experiments we conclude that the ratio of sample-to-pressure chamber volume is a critical parameter in maintaining sample quality at high pressure, and may affect the choice of pressure medium.

  12. Enhancement of Lipid Extraction from Marine Microalga, Scenedesmus Associated with High-Pressure Homogenization Process

    Directory of Open Access Journals (Sweden)

    Seok-Cheol Cho


    Full Text Available Marine microalga, Scenedesmus sp., which is known to be suitable for biodiesel production because of its high lipid content, was subjected to the conventional Folch method of lipid extraction combined with high-pressure homogenization pretreatment process at 1200 psi and 35°C. Algal lipid yield was about 24.9% through this process, whereas only 19.8% lipid can be obtained by following a conventional lipid extraction procedure using the solvent, chloroform : methanol (2 : 1, v/v. Present approach requires 30 min process time and a moderate working temperature of 35°C as compared to the conventional extraction method which usually requires >5 hrs and 65°C temperature. It was found that this combined extraction process followed second-order reaction kinetics, which means most of the cellular lipids were extracted during initial periods of extraction, mostly within 30 min. In contrast, during the conventional extraction process, the cellular lipids were slowly and continuously extracted for >5 hrs by following first-order kinetics. Confocal and scanning electron microscopy revealed altered texture of algal biomass pretreated with high-pressure homogenization. These results clearly demonstrate that the Folch method coupled with high-pressure homogenization pretreatment can easily destruct the rigid cell walls of microalgae and release the intact lipids, with minimized extraction time and temperature, both of which are essential for maintaining good quality of the lipids for biodiesel production.

  13. Enhancement of Lipid Extraction from Marine Microalga, Scenedesmus Associated with High-Pressure Homogenization Process (United States)

    Cho, Seok-Cheol; Choi, Woon-Yong; Oh, Sung-Ho; Lee, Choon-Geun; Seo, Yong-Chang; Kim, Ji-Seon; Song, Chi-Ho; Kim, Ga-Vin; Lee, Shin-Young; Kang, Do-Hyung; Lee, Hyeon-Yong


    Marine microalga, Scenedesmus sp., which is known to be suitable for biodiesel production because of its high lipid content, was subjected to the conventional Folch method of lipid extraction combined with high-pressure homogenization pretreatment process at 1200 psi and 35°C. Algal lipid yield was about 24.9% through this process, whereas only 19.8% lipid can be obtained by following a conventional lipid extraction procedure using the solvent, chloroform : methanol (2 : 1, v/v). Present approach requires 30 min process time and a moderate working temperature of 35°C as compared to the conventional extraction method which usually requires >5 hrs and 65°C temperature. It was found that this combined extraction process followed second-order reaction kinetics, which means most of the cellular lipids were extracted during initial periods of extraction, mostly within 30 min. In contrast, during the conventional extraction process, the cellular lipids were slowly and continuously extracted for >5 hrs by following first-order kinetics. Confocal and scanning electron microscopy revealed altered texture of algal biomass pretreated with high-pressure homogenization. These results clearly demonstrate that the Folch method coupled with high-pressure homogenization pretreatment can easily destruct the rigid cell walls of microalgae and release the intact lipids, with minimized extraction time and temperature, both of which are essential for maintaining good quality of the lipids for biodiesel production. PMID:22969270

  14. Novel High Temperature Capacitive Pressure Sensor Utilizing SiC Integrated Circuit Twin Ring Oscillators (United States)

    Scardelletti, M.; Neudeck, P.; Spry, D.; Meredith, R.; Jordan, J.; Prokop, N.; Krasowski, M.; Beheim, G.; Hunter, G.


    This paper describes initial development and testing of a novel high temperature capacitive pressure sensor system. The pressure sensor system consists of two 4H-SiC 11-stage ring oscillators and a SiCN capacitive pressure sensor. One oscillator has the capacitive pressure sensor fixed at one node in its feedback loop and varies as a function of pressure and temperature while the other provides a pressure-independent reference frequency which can be used to temperature compensate the output of the first oscillator. A two-day repeatability test was performed up to 500C on the oscillators and the oscillator fundamental frequency changed by only 1. The SiCN capacitive pressure sensor was characterized at room temperature from 0 to 300 psi. The sensor had an initial capacitance of 3.76 pF at 0 psi and 1.75 pF at 300 psi corresponding to a 54 change in capacitance. The integrated pressure sensor system was characterized from 0 to 300 psi in steps of 50 psi over a temperature range of 25 to 500C. The pressure sensor system sensitivity was 0.113 kHzpsi at 25C and 0.026 kHzpsi at 500C.

  15. Dynamic Temperature and Pressure Measurements in the Core of a Propulsion Engine (United States)

    Schuster, Bill; Gordon, Grant; Hultgren, Lennart S.


    Dynamic temperature and pressure measurements were made in the core of a TECH977 propulsion engine as part of a NASA funded investigation into indirect combustion noise. Dynamic temperature measurements were made in the combustor, the inter-turbine duct, and the mixer using ten two-wire thermocouple probes. Internal dynamic pressure measurements were made at the same locations using piezoresistive transducers installed in semi-infinite coils. Measurements were acquired at four steady state operating conditions covering the range of aircraft approach power settings. Fluctuating gas temperature spectra were computed from the thermocouple probe voltage measurements using a compensation procedure that was developed under previous NASA test programs. A database of simultaneously acquired dynamic temperature and dynamic pressure measurements was produced. Spectral and cross-spectral analyses were conducted to explore the characteristics of the temperature and pressure fluctuations inside the engine, with a particular focus on attempting to identify the presence of indirect combustion noise.

  16. Pressure hydrometallurgy: A new chance to non-polluting processes

    Directory of Open Access Journals (Sweden)

    Srećko R. Stopić


    Full Text Available A wide spectrum of hydrometallurgical processes offers many promising approaches for industrial application in order to improve the environmental impact of conventional metals productions, or for replacing hydrometallurgical processes whose gas emissions and a high content of formed metals (As, Cr, Pb are becoming increasingly unacceptable. The main advantages of pressure hydrometallurgy are fast kinetics, enhanced selectivity over iron and other dissolved species. The pioneer work on hydrometallurgical operation (dissolution, precipitation, metal winning was performed in Russia at the beginning of the previous century, mainly by Ipatieff and Bayer, each working independently in Saint Petersburg. Gradually, industrial application took place firstly in aluminium and later in nickel production. Today, in addition to nickel and aluminium, the pressure hydrometallurgy is well established in a wide spectrum of industrial applications for production of different metals (gold, zinc, molybdenium, titanium, germanium from ore deposits and secondary materials. High pressure leaching in combination with other metallurgical operations (cementation, precipitation, solvent extraction, and electrowinning provides an adequate technology to reintroduce lost metals into the industrial cycle, thereby saving resources and energy, while keeping the environment cleaner. It seems that pressure hydrometallurgy might be a very important key to better and nonpolluting processes in production of metals.

  17. Phase transitions in Cd3P2 at high pressures and high temperatures

    DEFF Research Database (Denmark)

    Yel'kin, F.S.; Sidorov, V.A.; Waskowska, A.


    The high-pressure, high-temperature structural behaviour of Cd3P2 has been studied using electrical resistance measurements, differential thermal analysis, thermo baric analysis and X-ray diffraction. At room temperature, a phase transformation is observed at 4.0 GPa in compression....... The experimental zero-pressure bulk modulus of the low-pressure phase is 64.7(7) GPa, which agrees quite well with the calculated value of 66.3 GPa using the tight-binding linear muffin-tin orbital method within the local density approximation. Tentatively, the high-pressure phase has an orthorhombic crystal...

  18. Hardness evolution of AZ80 magnesium alloy processed by HPT at different temperatures

    Directory of Open Access Journals (Sweden)

    Saad A. Alsubaie


    Full Text Available Discs of an extruded AZ80 magnesium alloy were processed by high-pressure torsion (HPT using 6.0 GPa up to 10 turns at different temperatures (296 K and 473 K. The disc surfaces and cross-sectional planes were examined before and after processing using scanning electron microscopy (SEM and Vickers microhardness (Hv. The microhardness results at the surface show differences in the strength of the material as a function of distance from the disc centres up to saturation, as well as a function of distance from the bottom to the surface in the cross-sectional plane. This study analyses the effect of processing temperature on the evolution of microhardness in the AZ80 magnesium alloy processed by high-pressure torsion. Keywords: Hardness, High-pressure torsion, Magnesium alloy, Severe plastic deformation

  19. Pressure and temperature effects on oxide melt structure: progress and prognoses (Bunsen Medal Lecture) (United States)

    Stebbins, J. F.


    Thanks to decades of study by diffraction and spectroscopy, many aspects of the short-range structure of oxide glasses, and the effects of composition on them, are relatively well known. In most cases, these results represent (at best) the structure of the liquid at the glass transition, which is often far below the magmatic conditions of greatest interest for geological processes. At the same time, detailed thermodynamic and calorimetric studies at ambient pressure, and a few pioneering in-situ, high-pressure melt property measurements, have documented the fact that melt structure must change considerably as temperature and pressure are increased. Closing the gap between magma properties and our atomic-scale view thus requires much better information about temperature and pressure effects on melt structure. Recent progress on temperature effects has been made both by in-situ studies, and by work at ambient conditions on glass samples prepared with different cooling rates and thus capturing the melt structure at different fictive temperatures. The former type has the advantage of a greater accessible range of temperatures but can be limited by the inherent difficulties of high temperature experiments; for the latter, any structural tool may be applied but changes over the accessible range (typically Tg to Tg+200 K or less) can be subtle. We now know, for example, that in some systems local structural changes can be detected for network cations such as B, Al, and even Si, but that these can lead to either coordination decreases with T (e.g. B), correlated with thermal expansion, or to increases with T (e.g. Al in Ca aluminosilicates), correlated with entropic effects. In some systems, increases in the disorder of the network with T can be measured and correlated with heats of reaction among various bridging oxygen species. In a few cases, network modifier environments (e.g. Ni, Mg, Na) can be seen to change with T as well. But in general, extrapolating results from

  20. Simultaneous Global Pressure and Temperature Measurement Technique for Hypersonic Wind Tunnels (United States)

    Buck, Gregory M.


    High-temperature luminescent coatings are being developed and applied for simultaneous pressure and temperature mapping in conventional-type hypersonic wind tunnels, providing global pressure as well as Global aeroheating measurements. Together, with advanced model fabrication and analysis methods, these techniques will provide a more rapid and complete experimental aerodynamic and aerothermodynamic database for future aerospace vehicles. The current status in development of simultaneous pressure- and temperature-sensitive coatings and measurement techniques for hypersonic wind tunnels at Langley Research Center is described. and initial results from a feasibility study in the Langley 31-Inch Mach 10 Tunnel are presented.

  1. The effect of temperature and pressure on the oxygen reduction reactions in polyelectrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Holdcroft, S.; Abdou, M.S.; Beattie, P.; Basura, V. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Chemistry


    The effect of temperature and pressure on the oxygen reduction reaction in polyelectrolyte membranes was described. Polyelectrolytes chosen for the experiment differed in composition, weight and flexibility of the polymer chains. The study was conducted in a solid state electrochemical cell at temperatures between 30 and 95 degrees C and in the pressure range of 1 to 5 atm. The solubility of oxygen in these membranes was found to follow Henry`s Law, while the diffusion coefficient decreased with pressure. The effect of temperature on the solubility of oxygen and the diffusion coefficient of oxygen in the membranes was similar to that observed in solution electrolytes. 2 refs., 3 figs.

  2. Numerical Analyses and Forecasting of Surface Air Temperature and Water Vapor Pressure. (United States)

    Analyses and forecasting of heat exchange, fog probability and visibility over the oceans and a number of other numerical environmental analyses/forecasts require a detailed analysis and forecasting of surface air vapor pressure and temperature. Based on earlier encouraging studies by a few Norwegian researchers, such response computation and numerical analysis/forecasting of surface air vapor pressure and temperature is outlined. It is shown that the changes of surface air properties, and sea- air temperature and vapor pressure differences are mainly determined by

  3. Equation of states and melting temperatures of diamond cubic and zincblende semiconductors: pressure dependence

    Energy Technology Data Exchange (ETDEWEB)

    Hung, V V; Hanh, P T M [Hanoi National Pedagogic University, Km8 Hanoi-Sontay Highway, Hanoi (Viet Nam); Masuda-Jindo, K [Department of Material Science and Engineering, Tokyo Institute of Technology, Nagasuta, Midori-ku, Yokohama 226-8503 (Japan); Hai, N T [Hanoi University of Technology, 01 Dai Co Viet Road, Hanoi (Viet Nam)], E-mail:


    The pressure dependence of the melting temperatures of tetrahedrally coordinated semiconductors are studied using the equation of states derived from the statistical moment method, in comparison with those of the normal metals. Using the general expressions of the limiting temperatures T{sub m}, we calculate the 'melting' temperatures of the semiconductor crystals and normal metals as a function of the hydrostatic pressure. The physical origins for the inverse pressure dependence of T{sub m} observed for tetrahedrally coordinated semiconductors are also discussed.

  4. Summing up dynamics: modelling biological processes in variable temperature scenarios

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Verdenius, F.


    The interest of modelling biological processes with dynamically changing external conditions (temperature, relative humidity, gas conditions) increases. Several modelling approaches are currently available. Among them are approaches like modelling under standard conditions, temperature sum models

  5. The effect of pressure and temperature pretreatment on the biogas output from algal biomass. (United States)

    Zieliński, Marcin; Dębowski, Marcin; Grala, Anna; Dudek, Magda; Kupczyk, Karolina; Rokicka, Magdalena


    This paper presents data on methane fermentation of algal biomass containing Chlorella sp. and Scenedesmus sp. The biomass was obtained from closed-culture photobioreactors. Before the process, the algae were subjected to low temperature and pressure pretreatment for 0.0, 0.5, 1.0 and 2.0 h. The prepared biomass was subjected to mesophilic methane fermentation. The amount and composition of the biogas formed in the process were determined. The amount of biogas produced was larger when the biomass was subjected to thermal preprocessing. The proportion of methane in the gas also increased. Extending the heating time beyond 1.0 h did not significantly improve the biogassing effects.

  6. Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream (United States)

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung; Parks, II, James E.


    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

  7. Temperature monitoring of tissue preparation processes (United States)

    Altshuler, Gregory B.; Erofeev, Andrew V.; Prikhodko, Constantin V.; Matyzhev, Gregory O.; Gerasimov, Roman V.


    This paper represents a complex of investigations concerned with temperature dynamics of pulp chamber for various temporal and power parameters of YAG:Ho laser. Comparison of overheating values at various modes of water cooling system operation is performed. Method of pulp chamber temperature measuring based on temperature monitoring of a checking point of a tooth surface is advanced. Moreover, the results of a special sub-research concentrated on thermal feedback signal at tooth tissues under YAG:Nd laser radiation treatment are offered also. Finally, method of recognizing of any diverse tooth tissue types, such as:bone, dentine, enamel and gum against a thermal response is demonstrated within the limits of this research.

  8. 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...

  9. Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

    Directory of Open Access Journals (Sweden)

    Zengling Ran


    Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

  10. Temperature and pressure adaptation of a sulfate reducer from the deep subsurface

    Directory of Open Access Journals (Sweden)

    Katja eFichtel


    Full Text Available Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301. The organism was isolated at 20 °C and atmospheric pressure from ~61 °C-warm sediments approximately five meters above the sediment-basement interface. In comparison to standard laboratory conditions (20 °C and 0.1 MPa, faster growth was recorded when incubated at in situ pressure and high temperature (45 °C, while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure.

  11. Normalized Temperature Contrast Processing in Flash Infrared Thermography (United States)

    Koshti, Ajay M.


    The paper presents further development in normalized contrast processing of flash infrared thermography method by the author given in US 8,577,120 B1. The method of computing normalized image or pixel intensity contrast, and normalized temperature contrast are provided, including converting one from the other. Methods of assessing emissivity of the object, afterglow heat flux, reflection temperature change and temperature video imaging during flash thermography are provided. Temperature imaging and normalized temperature contrast imaging provide certain advantages over pixel intensity normalized contrast processing by reducing effect of reflected energy in images and measurements, providing better quantitative data. The subject matter for this paper mostly comes from US 9,066,028 B1 by the author. Examples of normalized image processing video images and normalized temperature processing video images are provided. Examples of surface temperature video images, surface temperature rise video images and simple contrast video images area also provided. Temperature video imaging in flash infrared thermography allows better comparison with flash thermography simulation using commercial software which provides temperature video as the output. Temperature imaging also allows easy comparison of surface temperature change to camera temperature sensitivity or noise equivalent temperature difference (NETD) to assess probability of detecting (POD) anomalies.

  12. Short-term effects of air temperature on blood pressure and pulse pressure in potentially susceptible individuals. (United States)

    Lanzinger, Stefanie; Hampel, Regina; Breitner, Susanne; Rückerl, Regina; Kraus, Ute; Cyrys, Josef; Geruschkat, Uta; Peters, Annette; Schneider, Alexandra


    Only few epidemiological studies have investigated the association between air temperature and blood pressure (BP) or pulse pressure (PP), with inconsistent findings. We examined whether short-term changes in air temperature were associated with changes in BP or PP in three different populations. Between March 2007 and December 2008, 371 systolic and diastolic BP measurements were collected in 30 individuals with type-2 diabetes mellitus (T2D), 30 persons with impaired glucose tolerance and 42 healthy individuals without a metabolic disorder from Augsburg, Germany. Hourly means of ambient meteorological data were obtained from a fixed measurement station. Personal temperature measurements were conducted using data loggers. Temperature effects were evaluated using additive mixed models adjusting for time trend and relative humidity. Decreases in air temperature were associated with an increase in systolic BP, diastolic BP and PP in individuals with T2D. For example, a 1°C decrease in ambient temperature was associated with an immediate increase in systolic BP of 1.0 mmHg (95%-confidence interval: [0.5;1.4]mmHg). Effects of personally measured air temperature were similar. Temperature effects were modified by age, body mass index, gender, antihypertensive medication and whereabouts, such as being indoors. We observed associations between decreases in air temperature and increases in BP as well as PP in persons with T2D indicating that these people might be potentially more susceptible to changes in air temperature. Our findings may provide a hypothesis for a mechanism between air temperature decreases and short-term increases of cardiovascular events. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. High-Pressure High-Temperature Phase Diagram of the Organic Crystal Paracetamol (United States)

    Smith, Spencer; Montgomery, Jeffrey; Vohra, Yogesh

    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped diamond as heating anvil. The HPHT data obtained from boron-doped diamond heater is cross-checked with data obtained using a standard block heater diamond anvil cell. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in a number of different experiments. Solid state phase transitions from monoclinic Form I --> orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II --> unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. Our previous angle dispersive x-ray diffraction studies at the Advanced Photon Source has confirmed the existence of two unknown crystal structures Form IV and Form V of paracetamol at high pressure and ambient temperature. The phase transformation from Form II to Form IV occurs at ~8.5 GPa and from Form IV to Form V occurs at ~11 GPa at ambient temperature. Our new data is combined with the previous ambient temperature high-pressure Raman and X- ray diffraction data to create the first HPHT phase diagram of paracetamol. Doe-NNSA Carnegie DOE Alliance Center (CDAC) under Grant Number DE-NA0002006.

  14. Plantar Pressure and Foot Temperature Responses to Acute Barefoot and Shod Running

    Directory of Open Access Journals (Sweden)

    Priego Quesada Jose Ignacio


    Full Text Available Purpose. Increased contact pressure and skin friction may lead to higher skin temperature. Here, we hypothesized a relationship between plantar pressure and foot temperature. To elicit different conditions of stress to the foot, participants performed running trials of barefoot and shod running. Methods. Eighteen male recreational runners ran shod and barefoot at a self-selected speed for 15 min over different days. Before and immediately after running, plantar pressure during standing (via a pressure mapping system and skin temperature (using thermography were recorded. Results. No significant changes were found in plantar pressure after barefoot or shod conditions (p > 0.9. Shod running elicited higher temperatures in the forefoot (by 0.5-2.2°C or 0.1-1.2% compared with the whole foot, p -0.5, p > 0.05. Conclusions. The increase in temperature after the shod condition was most likely the result of footwear insulation. However, variation of the temperature in the rearfoot was higher after barefoot running, possible due to a higher contact load. Changes in temperature could not predict changes in plantar pressure and vice-versa.

  15. Water vaporization promotes coseismic fluid pressurization and buffers temperature rise

    NARCIS (Netherlands)

    Chen, Jianye|info:eu-repo/dai/nl/370819071; Niemeijer, André|info:eu-repo/dai/nl/370832132; Yao, Lu; Ma, Shengli


    We investigated the frictional properties of carbonate-rich gouge layers at a slip rate of 1.3 m/s, under dry and water-saturated conditions, while monitoring temperature at different locations on one of the gouge-host rock interfaces. All experiments showed a peak frictional strength of 0.4–0.7,

  16. Properties of Silicon Dioxide Film Deposited By PECVD at Low Temperature/Pressure

    Directory of Open Access Journals (Sweden)

    Meysam Zarchi


    Full Text Available conventional plasma enhanced chemical vapor deposition (PECVD at low temperature/pressure with silane (SiH4 and nitrous oxide (N2O as precursor gases. The ellipsometer and stress measurement system were used to test the thickness and refractive index uniformity of the SiO2 film fabricated. The effects of radio frequency (RF power chamber pressure and N2O/SiH4 flow ratio on the properties of SiO2 film were studied. The results show that the refractive index of SiO2 film is mainly determined by N2O/SiH4 flow ratio .Moreover, the formation of SiO2 thin films is confirmed by Fourier transform infrared (FTIR spectroscopy. The thickness and refractive indices of the films measured by ellipsometry C-V measurement show that the electrical properties are directly related to process parameters and Si/SiO2 interface. The MIS structures were also fabricated from optimized SiO2 layer to study C-V measurement and to estimate interface, oxide and effective border traps density. The deposited SiO2 films have good uniformity, compact structure, high deposition rate, low deposition temperature and controllable stress, which can be widely, used in semiconductor devices.

  17. High Pressure and Temperature Core Formation as an Alternative to the "Late Veneer" Hypothesis (United States)

    Righter, Kevin; Pando, K.; Humayun, M.; Danielson, L.


    The highly siderophile elements (HSE; Re, Au and the Platinum Group Elements - Pd Pt, Rh, Ru, Ir, Os) are commonly utilized to constrain accretion processes in terrestrial differentiated bodies due to their affinity for FeNi metal [1]. These eight elements exhibit highly siderophile behavior, but nonetheless have highly diverse metal-silicate partition coefficients [2]. Therefore the near chondritic relative concentrations of HSEs in the terrestrial and lunar mantles, as well as some other bodies, are attributed to late accretion rather than core formation [1]. Evaluation of competing theories, such as high pressure metal-silicate partitioning or magma ocean hypotheses has been hindered by a lack of relevant partitioning data for this group of eight elements. In particular, systematic studies isolating the effect of one variable (e.g. temperature or melt compositions) are lacking. Here we undertake new experiments on all eight elements, using Fe metal and FeO-bearing silicate melts at fixed pressure, but variable temperatures. These experiments, as well as some additional planned experiments should allow partition coefficients to be more accurately calculated or estimated at the PT conditions and compositions at which core formation is thought to have occurred.

  18. Inactivation of pathogenic bacteria in food matrices: high pressure processing, photodynamic inactivation and pressure-assisted photodynamic inactivation (United States)

    Cunha, A.; Couceiro, J.; Bonifácio, D.; Martins, C.; Almeida, A.; Neves, M. G. P. M. S.; Faustino, M. A. F.; Saraiva, J. A.


    Traditional food processing methods frequently depend on the application of high temperature. However, heat may cause undesirable changes in food properties and often has a negative impact on nutritional value and organoleptic characteristics. Therefore, reducing the microbial load without compromising the desirable properties of food products is still a technological challenge. High-pressure processing (HPP) can be classified as a cold pasteurization technique, since it is a non-thermal food preservation method that uses hydrostatic pressure to inactivate spoilage microorganisms. At the same time, it increases shelf life and retains the original features of food. Photodynamic inactivation (PDI) is also regarded as promising approach for the decontamination of food matrices. In this case, the inactivation of bacterial cells is achieved by the cytotoxic effects of reactive oxygens species (ROS) produced from the combined interaction of a photosensitizer molecule, light and oxygen. This short review examines some recent developments on the application of HPP and PDI with food-grade photosensitizers for the inactivation of listeriae, taken as a food pathogen model. The results of a proof-of-concept trial of the use of high-pressure as a coadjutant to increase the efficiency of photodynamic inactivation of bacterial endospores is also addressed.

  19. High-pressure processing as emergent technology for the extraction of bioactive ingredients from plant materials. (United States)

    Jun, Xi


    High-pressure processing is a food processing technique that has shown great potentials in the food industry. Recently, it was developed to extract bioactive ingredients from plant materials, known as ultrahigh pressure extraction (UPE), taking advantages of time saving, higher extraction yields, fewer impurities in the extraction solution, minimal heat and can avoid thermal degradation on the activity and structure of bioactive components, and so on. This review provides an overview of the developments in the UPE of bioactive ingredients from plant material. Apart from a brief presentation of the theories of UPE and extraction equipment systems, the principal parameters that influence the extraction efficiency to be optimized in the UPE (e.g., solvent, pressure, temperature, extraction time, and the number of cycle) were discussed in detail, and finally the more recent applications of UPE for the extraction of active compounds from plant materials were summarized.

  20. Data on blueberry peroxidase kinetic characterization and stability towards thermal and high pressure processing

    Directory of Open Access Journals (Sweden)

    Netsanet Shiferaw Terefe


    Full Text Available The data presented in this article are related to a research article entitled ‘Thermal and high pressure inactivation kinetics of blueberry peroxidase’ (Terefe et al., 2017 [1]. In this article, we report original data on the activity of partially purified blueberry peroxidase at different concentrations of hydrogen peroxide and phenlylenediamine as substrates and the effects of thermal and high pressure processing on the activity of the enzyme. Data on the stability of the enzyme during thermal (at temperatures ranging from 40 to 80 °C and combined thermal-high pressure processing (100–690 MPa, 30–90 °C are included in this report. The data are presented in this format in order to facilitate comparison with data from other researchers and allow statistical analyses and modeling by others in the field.

  1. Advanced lifetime PSP imaging system for pressure and temperature field measurement (United States)

    Mitsuo, Kazunori; Asai, Keisuke; Takahashi, Akira; Mizushima, Hiroshi


    The newly designed lifetime imaging system (LIS), which was composed of a multi-gated CCD camera and LED illuminators, has been developed to measure simultaneously pressure and temperature field from luminescent lifetime decay of pressure-sensitive paint (PSP). The new system could reduce the measurement error due to shot noise of a CCD and laser speckle, compared to the previous lifetime imaging system. Optimization of PSP film thickness on white basecoat was also conducted for improving measurement accuracy, and could minimize the measurement error. As a verification test, pressure and temperature images on a simple delta wing were visualized by the newly designed LIS. The quality of the pressure image was considerably improved in comparison with that measured by the previous system. These results indicated that the new LIS was a practical measurement tool to acquire simultaneously pressure and temperature field on an aerodynamic model surface.

  2. The general use of the time-temperature-pressure superposition principle

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    This note is a supplement to Dynamic of Polymeric Liquids (DPL) section 3.6(a). DPL do only concern material functions and only the effect of the temperature on these. This is a short introduction to the general use of the time-temperature-pressure superposition principle.......This note is a supplement to Dynamic of Polymeric Liquids (DPL) section 3.6(a). DPL do only concern material functions and only the effect of the temperature on these. This is a short introduction to the general use of the time-temperature-pressure superposition principle....

  3. Temperature and Pressure Sensors Based on Spin-Allowed Broadband Luminescence of Doped Orthorhombic Perovskite Structures (United States)

    Eldridge, Jeffrey I. (Inventor); Chambers, Matthew D. (Inventor)


    Systems and methods that are capable of measuring pressure or temperature based on luminescence are discussed herein. These systems and methods are based on spin-allowed broadband luminescence of sensors with orthorhombic perovskite structures of rare earth aluminates doped with chromium or similar transition metals, such as chromium-doped gadolinium aluminate. Luminescence from these sensors can be measured to determine at least one of temperature or pressure, based on either the intense luminescence of these sensors, even at high temperatures, or low temperature techniques discussed herein.

  4. Acute combined pressure and temperature exposures on a shallow-water crustacean: novel insights into the stress response and high pressure neurological syndrome. (United States)

    Morris, J P; Thatje, S; Ravaux, J; Shillito, B; Fernando, D; Hauton, C


    Little is known about the ecological and physiological processes governing depth distribution limits in species. Temperature and hydrostatic pressure are considered to be two dominant factors. Research has shown that some marine ectotherms are shifting their bathymetric distributions in response to rapid anthropogenic ocean surface warming. Shallow-water species unable to undergo latitudinal range shifts may depend on bathymetric range shifts to seek refuge from warming surface waters. As a first step in constraining the molecular basis of pressure tolerance in shallow water crustaceans, we examined differential gene expression in response to acute pressure and temperature exposures in juveniles of the shallow-water shrimp Palaemonetes varians. Significant increases in the transcription of genes coding for an NMDA receptor-regulated protein, an ADP ribosylation factor, β-actin, two heat shock protein 70 kDa isoforms (HSP70), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were found in response to elevated pressure. NMDA receptors have been implicated in pathways of excitotoxic damage to neurons and the onset of high pressure neurological syndrome (HPNS) in mammals. These data indicate that the sub-lethal effects of acute barotrauma are associated with transcriptional disturbances within the nervous tissue of crustaceans, and cellular macromolecular damage. Such transcriptional changes lead to the onset of symptoms similar to that described as HPNS in mammals, and may act as a limit to shallow water organisms' prolonged survival at depth. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Combined Effect of Pressure and Temperature on the Viscous Behaviour of All-Oil Drilling Fluids

    National Research Council Canada - National Science Library

    Hermoso, J; Martínez-Boza, F; Gallegos, C


    .... Drilling fluid viscous flow characterization was performed with a controlled-stress rheometer, using both conventional coaxial cylinder and non-conventional geometries for High Pressure/High Temperature (HPHT) measurements...

  6. Novel High-Temperature Pressure Sensors for Extreme Service Applications Project (United States)

    National Aeronautics and Space Administration — This Phase I research will result in a prototype high temperature pressure sensing cell based on the piezoresistive properties of platinum:tungsten alloys. The...


    National Aeronautics and Space Administration — This data set contains over 21000 temperature-pressure profiles (TPS files) of the neutral atmosphere derived from Mars Global Surveyor (MGS) radio occultation data....

  8. Pressure heterogeneity in small displacement electrohydraulic forming processes


    Daehn, G. S.; Fenton, G; Vohnout, V. J.


    Electrohydraulic (submerged arc discharge) forming of sheet metal parts has been used as a specialized high speed forming method since the 1960 s. The parts formed generally had a major dimension in the 5 to 25 cm range and required gross metal expansion in the centimeter range. In the descriptions of this process found in the literature, the pressure front emanating from the initial plasma generated by the arc is considered to be uniformly spherical in nature. At least one commercial system ...

  9. Physical processes determining the chromospheric temperature distribution (United States)

    Jordan, S. D.


    It is demonstrated that short period acoustic waves appear adequate to heat the low chromosphere in the region just above the temperature minimum, these waves are unlikely to provide sufficient energy to heat the chromosphere above tau-5000 A(normal) less than 10 to the -6th. Calculations also show that the electron density to H density ratio from chromospheric models is too low for the H2 molecule to affect the population of H(-).

  10. PREFACE: Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (United States)

    Liu, Haozhe; Wenk, Hans-Rudolf; Duffy, Thomas S.


    mm3) of materials can be deformed at pressure and temperature. Unfortunately these experiments do not currently extend to pressures of the lower mantle, which comprises most of the volume of the Earth. Thus deformation mechanisms of minerals such as perovskite (in the lower mantle), post-perovskite (in the anisotropic D" zone) and epsilon-iron (in the inner core) remain enigmatic. Here developments in the DAC offer new opportunities. At present, this is a novel, and in many ways still very primitive, method to deform minerals at high pressure, confined to room temperature and moderate strains. No doubt this will change in the near future as new technologies become implemented, for example laser heating, remote pressure control, especially fine control of strain rate during compression, decompression and cycling procedures for DAC radial diffraction studies. The first paper, by Bassett, gives a perspective on the significance of stress in DAC experiments. An issue once considered by many a nuisance has become a gold mine when it comes to unravelling material properties at very high pressures. At high pressures many silicates and oxides become ductile, even at room temperature, and ductile deformation results in development of preferred orientation that can be used to infer deformation mechanisms as illustrated in the reviews by Wenk et al and Merkel. Mao et al investigate the strength of solidified argon and find it increases greatly and exceeds 2.7~GPa with applied pressure at 55 GPa. Singh et al investigate the dependence of strength on grain size by studying nanocrystalline gold, while Yoneda and Kubo use axial diffraction geometry to determine both mean pressure and deviatoric stress of gold. Miyagi et al illustrate the Rietveld method for quantitative texture analysis of CaSiO3 perovskite. Speziale et al map strain gradients in the DAC by investigating texture variations in copper to 25 GPa. Naturally, efficient and accurate image processing is a requirement for

  11. Temperature and pressure effects during erbium laser stapedotomy. (United States)

    Pratisto, H; Frenz, M; Ith, M; Romano, V; Felix, D; Grossenbacher, R; Altermatt, H J; Weber, H P


    Laser-assisted stapedotomy has become a well-established alternative to the mechanical drilling method. The goal of this study is to quantify the mechanical and thermal tissue effects and to determine optimum erbium laser parameters for safe clinical treatment. On an inner ear model, time-resolved pressure measurements and Schlieren optical flash photography were performed during the perforation of the stapes foot plate using an erbium laser at 2.79 microns. The laser radiation was transmitted via an optical zirconium fluoride fiber. The laser-treated foot plates were investigated by light microscopy and scanning electron microscopy to visualise the laser-induced tissue effects. Perforation of the stapes foot plate can be performed with a few erbium laser pulses with high precision and a thermal damage zone of vapor channel created in the perilymph after fenestration. From the comparison of the laser-induced pressure with the limit graph to avoid hearing defects published by Pfander, an unobjectionable use of the erbium laser is deduced for fluences < 10 J/cm2. The erbium laser seems to represent an ideal instrument for middle ear surgery with all the advantages (precision, fiber optic transportable, high ablation efficiency, safety) desired for clinical application.

  12. Uncertainties in risk assessment of hydrogen discharges from pressurized storage vessels at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, D.; Baraldi, D.


    20K) e.g. the cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types. The vessel...

  13. Hydrogen oxidation at high pressure and intermediate temperatures: experiments and kinetic modeling

    DEFF Research Database (Denmark)

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


    Hydrogen oxidation at 50 bar and temperatures of 700–900 K was investigated in a high pressure laminar flow reactor under highly diluted conditions. The experiments provided information about H 2 oxidation at pressures above the third explosion limit. The fuel–air equivalence ratio of the reactants...

  14. Pressure effect on the low-temperature remanences of multidomain magnetite: Change in the Verwey transition temperature (United States)

    Sato, M.; Yamamoto, Y.; Nishioka, T.; Kodama, K.; Mochizuki, N.; Tsunakawa, H.


    The Verwey transition of magnetite is the basic issues for the rock magnetism, since main magnetic mineral of terrestrial rocks is magnetite and its associates. One of the most important issues concerning the Verwey transition is the change in transition temperature (Tv) due to pressure, which is thought to improve our understanding of its electric and magnetic nature in relation to the phase diagram. Recently, the opposite pressure effects of the transition temperature were reported applying the different experimental method. Measuring the electrical resistivity of single crystalline samples, Môri et al. [2002] reported that Tv becomes lower with increasing pressure by 9 GPa. In contrast, Pasternak et al. [2003] reported from Mössbauer experiment that transition temperature becomes higher with increasing pressure by 30 GPa. Thus the change in transition temperature with pressure has been controversial, and nature of the Verwey transition is still unclear. The magnetic property measurements using low temperature cycle are a powerful tool for identifying the state of magnetic minerals. Carporzen and Gilder [2010] conducted the thermal demagnetization experiment of low-temperature remanences of magnetite, and observed an increase in Tv with increasing pretreated pressure. From this result, they suggested that the Verwey transition of magnetite have the potential of a geobarometer. Modern techniques of high-pressure experiments enable us to measure sample magnetizations under pressure [Gilder et al., 2002; Kodama and Nishioka, 2005; Sadykov et al., 2008]. In the present study, systematic experiments of low-temperature remanences have been conducted for powder samples of stoichiometric magnetite under pressure up to 0.7 GPa using the high-pressure cell specially designed for MPMS, which was made of CuBe and ZrO2 [Kodama and Nishioka, 2005]. Natural magnetite of large single crystals were crushed by hand and sieved in an ultrasonic bath to be ~50 μm in size. For

  15. Exploring nuclear magnetic resonance at the highest pressure. Closing the pseudogap under pressure in a high temperature superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Thomas


    In the present work, a novel probe design for high pressure NMR experiments in gem anvil cells (GAC) was used which places a small microcoil inside the high pressure volume as the detection coil. Based on tests carried out at ambient pressure and high pressure of 42 kbar it is demonstrated that this approach is indeed feasible and results in an increase of sensitivity by two orders of magnitude compared to previous GAC-NMR designs. The design was then successfully employed in the investigation of the electronic properties of metallic aluminum and the high temperature superconductor YBa{sub 2}Cu{sub 4}O{sub 8} at pressures of up to 101 kbar. Because of its improved sensitivity and the potential to achieve even higher pressures, the microcoil GAC-NMR setup should prove useful in the investigation of materials under high pressure conditions in the future. In the case of metallic aluminum, the effect of pressure on the electronic density of states at the Fermi level was probed via the Knight-shift K and the spin-lattice relaxation time T{sub 1} at room temperature up to a pressure of 101 kbar, extending the pressure range of previous NMR measurements by a factor of 14 [72]. Most notably, a decrease of K(p) by 11% is detected in the investigated pressure range that is inconsistent with a free electron behavior of the density of states. Numerical band structure calculations that are in excellent agreement with the experimental data suggest that the observed changes of K and T{sub 1} are due to a kink in the electronic states at a Lifshitz-transition at about 75 kbar which has not been observed previously. A further decrease of K by a factor of 2 is predicted to occur in the pressure range up to 300 kbar. In addition, an increase of the NMR linewidths of the metallic aluminum signal was observed above about 42 kbar that is inconsistent with a pure dipolar linewidth. Based on an analysis of the field dependence of this effect it was ascribed to a small additional

  16. The Effects of Temperature and Pressure on the Porosity Evolution of Flechtinger Sandstone (United States)

    Hassanzadegan, Alireza; Blöcher, Guido; Milsch, Harald; Urpi, Luca; Zimmermann, Günter


    A porosity change influences the transport properties and the elastic moduli of rock while circulating water in a geothermal reservoir. The static and dynamic elastic moduli can be derived from the slope of stress-strain curves and velocity measurements, respectively. Consequently, the acoustic velocities were measured while performing hydrostatic drained tests. The effect of temperature on static and dynamic elastic moduli and porosity variations of Flechtinger sandstone was investigated in a wide range of confining pressure from 2 to 55 MPa. The experiments were carried out in a conventional triaxial system whereas the pore pressure remained constant, confining pressure was cycled, and temperature was increased step wise (25, 60, 90, 120, and 140 °C). The porosity variation was calculated by employing two different theories: poroelasticity and crack closure. The porosity variation and crack porosity were determined by the first derivative of stress-strain curves and the integral of the second derivative of stress-strain curves, respectively. The crack porosity analysis confirms the creation of new cracks at high temperatures. The porosity variation was increasing with an increase in temperature at low effective pressures and was decreasing with a rise in temperature at high effective pressures. Both compressional and shear wave velocities were increasing with increasing pressure due to progressive crack closure. Furthermore, the thermomechanical behavior of Flechtinger sandstone was characterized by an inversion effect where the sign of the temperature derivative of the drained bulk modulus changes.

  17. An arc tangent function demodulation method of fiber-optic Fabry-Perot high-temperature pressure sensor (United States)

    Ren, Qianyu; Li, Junhong; Hong, Yingping; Jia, Pinggang; Xiong, Jijun


    A new demodulation algorithm of the fiber-optic Fabry-Perot cavity length based on the phase generated carrier (PGC) is proposed in this paper, which can be applied in the high-temperature pressure sensor. This new algorithm based on arc tangent function outputs two orthogonal signals by utilizing an optical system, which is designed based on the field-programmable gate array (FPGA) to overcome the range limit of the original PGC arc tangent function demodulation algorithm. The simulation and analysis are also carried on. According to the analysis of demodulation speed and precision, the simulation of different numbers of sampling points, and measurement results of the pressure sensor, the arc tangent function demodulation method has good demodulation results: 1 MHz processing speed of single data and less than 1% error showing practical feasibility in the fiber-optic Fabry-Perot cavity length demodulation of the Fabry-Perot high-temperature pressure sensor.

  18. Pressure effect of glass transition temperature in Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk metallic glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Roseker, W.; Sikorski, M.


    Pressure effects on glass transition temperature and supercooled liquid region of a Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass have been investigated by performing in situ high-temperature and high-pressure x-ray powder diffraction measurements using synchrotron radiation. The glass transition was det...... range of 0-2.2 GPa. This method opens a possibility to study the pressure effect of glass transition process in glassy systems under high pressures (>1 GPa). (C) 2004 American Institute of Physics....

  19. Determination of interfacial heat transfer coefficient and its application in high pressure die casting process

    Directory of Open Access Journals (Sweden)

    Cao Yongyou


    Full Text Available In this paper, the research progress of the interfacial heat transfer in high pressure die casting (HPDC is reviewed. Results including determination of the interfacial heat transfer coefficient (IHTC, influence of casting thickness, process parameters and casting alloys on the IHTC are summarized and discussed. A thermal boundary condition model was developed based on the two correlations: (a IHTC and casting solid fraction and (b IHTC peak value and initial die surface temperature. The boundary model was then applied during the determination of the temperature field in HPDC and excellent agreement was found.

  20. Effects of various chemical cleaning conditions for pressured MF process. (United States)

    Lee, Chang-Kyu; Park, Chansoo; Choi, June-Seok; Kim, Jong-Oh


    A pilot-scale pressured hollow-fiber microfiltration (MF) process as pretreatment for the reverse osmosis process was studied and operated under various conditions to assess the relative influence of backwashing, chemical enhanced backwashing (CEB), and bag filter application. The pilot plant process consisted of backwashing but without the CEB or the bag filter as the first step of the research. As the second step of the research, the impact of the backwashing on permeability recovery was assessed at different intervals followed by the influence of CEB on flowrate recovery. Results from operating the pilot-scale hollow-fiber membrane modules for more than 1 year have demonstrated that the appropriate pore size of bag filters was 25-50 μm and the optimized backwashing process was every 30 minutes with 25 mg/L of NaOCl, and CEB with an interval of 10 cycles with the use of 100 mg/L NaOCl.

  1. A dual-unit pressure sensor for on-chip self-compensation of zero-point temperature drift (United States)

    Wang, Jiachou; Li, Xinxin


    A novel dual-unit piezoresistive pressure sensor, consisting of a sensing unit and a dummy unit, is proposed and developed for on-chip self-compensation for zero-point temperature drift. With an MIS (microholes inter-etch and sealing) process implemented only from the front side of single (1 1 1) silicon wafers, a pressure sensitive unit and another identically structured pressure insensitive dummy unit are compactly integrated on-chip to eliminate unbalance factors induced zero-point temperature-drift by mutual compensation between the two units. Besides, both units are physically suspended from silicon substrate to further suppress packaging-stress induced temperature drift. A simultaneously processes ventilation hole-channel structure is connected with the pressure reference cavity of the dummy unit to make it insensitive to detected pressure. In spite of the additional dummy unit, the sensor chip dimensions are still as small as 1.2 mm × 1.2 mm × 0.4 mm. The proposed dual-unit sensor is fabricated and tested, with the tested sensitivity being 0.104 mV kPa-1 3.3 V-1, nonlinearity of less than 0.08% · FSO and overall accuracy error of ± 0.18% · FSO. Without using any extra compensation method, the sensor features an ultra-low temperature coefficient of offset (TCO) of 0.002% °C-1 · FSO that is much better than the performance of conventional pressure sensors. The highly stable and small-sized sensors are promising for low cost production and applications.

  2. Thermoforming process for fabricating oral appliances: influence of heating and pressure application timing on formability. (United States)

    Yamada, Junko; Maeda, Yoshinobu


    This study was designed to examine the influence of heating and pressure application timing for thermoplastic soft materials on formability during the thermoforming process. Ethylene vinyl acetate (EVA) and a high shock-absorbing material (Hybrar) were used. Five specimens (20 x 10 x 4 mm) were heated to temperatures of 60, 80, 100, 120, 140, 160, 180, and 200 degrees C and then placed under a 4 N static weight with an indentation tip. The forming capability index (FI) was evaluated by rating the shape, size, and surface texture changes of the indentation tip reproduction in specimens using specially developed scales. The suitable temperature range for forming (STF) was determined by FI. Heat-holding capability of the two materials was also evaluated by the temperature changes in the cooling process using a digital thermometer. Timing of air pressure application was examined with the time-dependent change in negative pressure among three types of forming machines. STF of the EVA (80-120 degrees C) was lower than that for Hybrar (140-160 degrees C). The time required to reach the lower limit of the STF was statistically different between the two materials (EVA: 41 seconds, Hybrar: 13 seconds) (p < 0.05). The maximum negative pressure (MNP) of the three forming machines ranged from -12 to -60 cmHg and time to reach the temperature, 5-60 seconds. The results suggest that heating conditions for each type of sheet material should be predetermined by the STF. Forming process should be performed with the high MNP before reaching the lower limit of the STF.

  3. High-temperature high-pressure gas cleanup with ceramic bag filters. Draft final report

    Energy Technology Data Exchange (ETDEWEB)

    Shackleton, M.; Chang, R.; Sawyer, J.; Kuby, W.; Turner-Tamiyasu, E.


    Advanced processes designed for the efficient use of coal in the production of energy will benefit from, or even depend upon, highly efficient, economical, high-temperature removal systems for fine particulates. In the case of pressurized fluidized-bed combustion (PFBC), the hot gas cleanup device must operate at approximately 1600/sup 0/F. Existing commercial filter systems are temperature limited due to the filter material, but ceramic fibers intended for refractory insulation offer the promise of a practical high-temperature filter media if they can be incorporated into a design which combines filter performance with acceptable durability. The current work was initiated to further develop and demonstrate on a larger-scale basis, a ceramic fiber filtration system for application to coal-fired PFBC's. The development effort centered around the need to replace the knit metal wire scrim, used in earlier designs as support for the fine fiber ceramic mat filtration medium, with a corrosion-resistant material. This led to the selection of woven ceramic cloth for support of the mat layer. Because of the substantial difference in strength and other material properties between the metal and ceramic cloth, tests were necessary to optimize the filter; pulse parameters such as pulse duration, pulse pressure, and pulse injection orifice size; woven cloth mesh configuration; the technique for clamping the bag to the support; and similar structural, fluid, and control parameters. The demonstration effort included both tests to prove this concept in a real application and a systems analysis to show commercial feasibility of the ceramic filtration approach for hot gas cleanup in PFBC's. 12 references, 57 figures, 23 tables.

  4. Neutron spin echo studies of the effects of temperature and pressure in a ternary microemulsion

    CERN Document Server

    Kawabata, Y; Seto, H; Takeda, T; Komura, S; Schwahn, D


    In order to clarify the self-assembling mechanisms in complex fluids involving amphiphiles, we have investigated dynamic features of amphiphilic membranes and droplets at high temperature and at high pressure in a ternary microemulsion, consisting of AOT, water, and n-decane. A high-pressure cell for neutron spin echo (NSE) experiments has been improved, and the static and dynamic features of droplets are observed in detail by means of small angle neutron scattering and NSE. It is found that the size fluctuation and the diffusion of droplets are enhanced by increasing temperature, while they are suppressed by increasing pressure. (orig.)

  5. Design Strategies for Optically-Accessible, High-Temperature, High-Pressure Reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. F. Rice; R. R. Steeper; C. A. LaJeunesse; R. G. Hanush; J. D. Aiken


    The authors have developed two optical cell designs for high-pressure and high-temperature fluid research: one for flow systems, and the other for larger batch systems. The flow system design uses spring washers to balance the unequal thermal expansions of the reactor and the window materials. A typical design calculation is presented showing the relationship between system pressure, operating temperature, and torque applied to the window-retaining nut. The second design employs a different strategy more appropriate for larger windows. This design uses two seals: one for the window that benefits from system pressure, and a second one that relies on knife-edge, metal-to-metal contact.

  6. Design strategies for optically-accessible, high-temperature, high-pressure reactor

    Energy Technology Data Exchange (ETDEWEB)

    S. F. Rice; R. R. Steeper; C. A. LaJeunesse; R. G. Hanush; J. D. Aiken


    The authors have developed two optical cell designs for high-pressure and high-temperature fluid research: one for flow systems, and the other for larger batch systems. The flow system design uses spring washers to balance the unequal thermal expansions of the reactor and the window materials. A typical design calculation is presented showing the relationship between system pressure, operating temperature, and torque applied to the window-retaining nut. The second design employs a different strategy more appropriate for larger windows. This design uses two seals: one for the window that benefits from system pressure, and a second one that relies on knife-edge, metal-to-metal contact.

  7. Transport properties of natural gas through polyethylene nanocomposites at high temperature and pressure

    DEFF Research Database (Denmark)

    Adewole, Jimoh K.; Jensen, Lars; Al-Mubaiyedh, Usamah A.


    High density polyethylene (HDPE)/clay nanocomposites containing nanoclay concentrations of 1, 2.5, and 5 wt% were prepared by a melt blending process. The effects of various types of nanoclays and their concentrations on permeability, solubility, and diffusivity of natural gas in the nanocomposites...... were investigated. The results were compared with HDPE typically used in the production of liners for the petroleum industry. Four different nanoclays-Cloisite 10A, 15A, 30B and Nanomer 1.44P-were studied in the presence of CH4 and a CO2/CH4 mixture in the temperature range 30-70 degrees C and pressure...... of the CO2/CH4 mixture in Nanomer 1.44P nanocomposite was reduced by 47% and diffusion coefficient by 35% at 5 wt% loading, 50 degrees C, and 100 bar, compared with pure HDPE....

  8. Temperature, Pressure and Velocity measurements on the Ranque-Hilsch Vortex Tube (United States)

    Liew, R.; Zeegers, J. C. H.; Kuerten, J. G. M.; Michałek, W. R.


    Temperatures, pressures and velocities were measured in a Ranque-Hilsch vortex tube. Results show that the cooling power is larger than the heating power due to a heat loss to the surroundings. This heat loss became the more dominant thermodynamic process at large cold fractions (the ratio of cold mass flow over total mass flow). The velocities were obtained by means of Laser Doppler Anemometry. By this method, the three dimensional velocities of the gas and their standard deviations in the vortex tube are revealed by an non-intrusive measurement method. The turbulent fluctuations, characterized by the standard deviations, show that the turbulence is isotropic in the core region of the vortex tube.

  9. Synthesis of hydrogen-carbon clathrate material and hydrogen evolution therefrom at moderate temperatures and pressures (United States)

    Lueking, Angela [State College, PA; Narayanan, Deepa [Redmond, WA


    A process for making a hydrogenated carbon material is provided which includes forming a mixture of a carbon source, particularly a carbonaceous material, and a hydrogen source. The mixture is reacted under reaction conditions such that hydrogen is generated and/or released from the hydrogen source, an amorphous diamond-like carbon is formed, and at least a portion of the generated and/or released hydrogen associates with the amorphous diamond-like carbon, thereby forming a hydrogenated carbon material. A hydrogenated carbon material including a hydrogen carbon clathrate is characterized by evolution of molecular hydrogen at room temperature at atmospheric pressure in particular embodiments of methods and compositions according to the present invention.

  10. High Temperature Processable Flexible Polymer Films (United States)

    Sundar, D. Shanmuga; Raja, A. Sivanantha; Sanjeeviraja, C.; Jeyakumar, D.

    Recent developments in the field of flexible electronics motivated the researchers to start working in verdict of new flexible substrate for replacing the existing rigid glass and flexible plastics. Flexible substrates offer significant rewards in terms of being able to fabricate flexible electronic devices that are robust, thinner, conformable, lighter and can be rolled away when needed. In this work, a new flexible and transparent substrate with the help of organic materials such as Polydimethylsiloxane (PDMS) and tetra ethoxy orthosilicate (TEOS) is synthesized. Transmittance of about 90-95% is acquired in the visible region (400-700nm) and the synthesized substrate shows better thermal characteristics and withstands temperature up to 200∘C without any significant degradation. Characteristics such as transmittance (T), absorption (A), reflectance (R), refractive index (n) and extinction coefficient (k) are also reported.

  11. Pressure and temperature data from bottom-mounted pressure recorders to assist in the definition of net circulation through the Florida Keys, 2001-2003 (NODC Accession 0000826) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and pressure data were collected using pressure gauge in the Northwest Atlantic Ocean and Florida Bay from 11 September 2001 to 23 April 2003....


    Directory of Open Access Journals (Sweden)

    Emil Sasimowski


    Full Text Available The paper reports the results of a study on the effect of selected conditions of a pressure-bubble vacuum forming for polystyrene sheet on the non-uniformity of wall thickness of finished parts. The investigation was performed using DOE methods. Variables for the tests included temperatures in the external and internal zones of the heaters as well as heating time. The results demonstrate that the heating time and temperature in the internal zone formed by the heater have a statistically significant effect on the finished part’s wall thickness at the measuring points. It has been found that the side walls and bottom of the finished part are uniformly deformed, and thus exhibit the lowest wall thickness non-uniformity at a heating time of 22s (corresponding to the middle of the measuring range. Also, it is observed that the application of low temperatures in both zones of the heater has a positive effect. Due to the use of bubble, the finished parts exhibit a much lower wall thickness non-uniformity compared to those produced without bubble.

  13. 40 CFR 1065.120 - Fuel properties and fuel temperature and pressure. (United States)


    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Fuel properties and fuel temperature... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel properties and fuel temperature and pressure. (a) Use fuels as specified in the standard-setting part, or as...

  14. Effect of Contact Pressure on the Resistance Contact Value and Temperature Changes in Copper Busbar Connection

    Directory of Open Access Journals (Sweden)

    Agus Risdiyanto


    Full Text Available This paper discussed the influence of tightness or contacts pressure on copper busbar joints to determine changes in the value of the initial contact resistance and the maximum temperature at the joint due to high current load. The test sample was copper busbar 3 x 30 mm with configuration of bolted overlapping joint. Increasing contact pressure at the joint was measured to find out its effect on the value of contact resistance. The applied pressure was 6 to 36 MPa. Procedure of contact resistance measurement refer to the ASTM B539 standard using four-wire method. The sample subsequently loaded with the current of 350 A for 60 minutes and the maximum temperature at the joint was measured. The result showed that increasing contact pressure at the busbar joint will reduce the contact resistance and maximum temperature. The increase of contact pressure from 6 to 30 MPa causes decreasing contact resistance from 16 μΩ to 11 μΩ. Further increasing of contact pressure more than 30 MPa did not affect the contact resistance significantly. The lowest temperatur of busbar joint of 54°C was reached at a contact pressure of 36 Mpa.

  15. $\\mu$SR-Measurements under High Pressure and at Low Temperatures

    CERN Multimedia


    High pressure causes changes in the volume available to each atom in a solid and will therefore influence local properties like the electronic charge and spin densities and, in the case of magnetic materials, the spin ordering.\\\\ \\\\ The positive muon is known to be an interesting probe particle for the study of certain problems in magnetism. It has in fact been used for one high pressure experiment earlier in CERN, but the present experiments aim at more systematic studie For this purpose it is necessary to carry out pressure experiments at low temperatures. The new experiments use a helium gas pressure system, which covers the temperature range 10-300 K at pressures up to 14 Kbar.\\\\ \\\\ Experiments are in progress on \\item 1)~~~~Ferromagnetic metals like Fe, Co, Ni where the pressure dependence of the local magnetic field ~~~is studied at 77 K and at room temperature. \\item 2)~~~~Knight shifts in semimetals, where in the case of Sb strong variations with temperature and ~~~pressure are observed. \\end{enumerat...

  16. Research of a Novel Ultra-High Pressure Sensor with High-Temperature Resistance

    Directory of Open Access Journals (Sweden)

    Guo-Dong Zhang


    Full Text Available Ultra-high pressure measurement has significant applications in various fields such as high pressure synthesis of new materials and ultra-high pressure vessel monitoring. This paper proposes a novel ultra-high pressure sensor combining a truncated-cone structure and a silicon-on-insulator (SOI piezoresistive element for measuring the pressure up to 1.6 GPa. The truncated-cone structure attenuates the measured pressure to a level that can be detected by the SOI piezoresistive element. Four piezoresistors of the SOI piezoresistive element are placed along specific crystal orientation and configured as a Wheatstone bridge to obtain voltage signals. The sensor has an advantage of high-temperature resistance, in that the structure of the piezoresistive element can avoid the leakage current at high temperature and the truncated-cone structure separates the piezoresistive element from the heat environment. Furthermore, the upper surface diameter of the truncated-cone structure is designed to be 2 mm for the application of small scale. The results of static calibration show that the sensor exhibits a good performance in hysteresis and repeatability. The temperature experiment indicates that the sensor can work steadily at high temperature. This study would provide a better insight to the research of ultra-high pressure sensors with larger range and smaller size.

  17. Thermodynamic Analysis about Nucleation and Growth of Cubic Boron Nitride Crystals in the hBN-Li3N System under High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Xiao-Fei Guo


    Full Text Available The nucleation of cubic boron nitride (cBN single crystals synthesized with lithium nitride (Li3N as a catalyst under high pressure and high temperature (HPHT was analyzed. Many nanometer-sized cubic boron nitride nuclei formed in the near surface layer, as detected by high resolution transmission electron microscopy. Based on the experiment results, the transformation kinetics is described by a nucleation and growth process in the thermodynamic stability region of cBN. A theoretical description is developed based on the heterogeneous nucleation and layer growth mechanism, and the relevant parameters are estimated and discussed. The critical crystal radius, r*, increases with the temperature under constant pressure; the change with temperature more pronounced at lower pressure (such as 4.5 GPa. The crystal growth velocity increased with the temperature, and it is parabolic with temperature under certain pressure. These results are consistent with experimental data.

  18. Study of the Effects of Temperature and Pressure on the Thermodynamic and Acoustic Properties of 2-Methyl-1-butanol at Temperatures from 293K to 318K and Pressures up to 100MPa (United States)

    Dzida, Marzena


    The speeds of sound in 2-methyl-1-butanol were measured at temperatures from 293K to 318K and pressures up to 101MPa. The densities were measured in the same temperature range under atmospheric pressure. The isobaric specific heat capacities were measured at atmospheric pressure and temperatures from 284K to 355K. The densities, isobaric heat capacities, isobaric thermal expansions, isentropic compressibilities, isothermal compressibilities, and internal pressures as functions of temperature and pressure were calculated using the experimental speeds of sound under elevated pressures together with the densities and heat capacities at atmospheric pressure. The effects of temperature and pressure on the isobaric thermal expansion and internal pressure of 2-methyl-1-butanol are discussed and compared with those of pentan-1-ol, 2-methyl-2-butanol, and pentan-3-ol.

  19. An Integrative Genomic Island Affects the Adaptations of Piezophilic Hyperthermophilic Archaeon Pyrococcus yayanosii to High Temperature and High Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Zhen Li


    Full Text Available Deep-sea hydrothermal vent environments are characterized by high hydrostatic pressure and sharp temperature and chemical gradients. Horizontal gene transfer is thought to play an important role in the microbial adaptation to such an extreme environment. In this study, a 21.4-kb DNA fragment was identified as a genomic island, designated PYG1, in the genomic sequence of the piezophilic hyperthermophile Pyrococcus yayanosii. According to the sequence alignment and functional annotation, the genes in PYG1 could tentatively be divided into five modules, with functions related to mobility, DNA repair, metabolic processes and the toxin-antitoxin system. Integrase can mediate the site-specific integration and excision of PYG1 in the chromosome of P. yayanosii A1. Gene replacement of PYG1 with a SimR cassette was successful. The growth of the mutant strain ∆PYG1 was compared with its parent strain P. yayanosii A2 under various stress conditions, including different pH, salinity, temperature and hydrostatic pressure. The ∆PYG1 mutant strain showed reduced growth when grown at 100 °C, while the biomass of ∆PYG1 increased significantly when cultured at 80 MPa. Differential expression of the genes in module Ⅲ of PYG1 was observed under different temperature and pressure conditions. This study demonstrates the first example of an archaeal integrative genomic island that could affect the adaptation of the hyperthermophilic piezophile P. yayanosii to high temperature and high hydrostatic pressure.

  20. Effect of working pressure and annealing temperature on ...

    Indian Academy of Sciences (India)

    C. The deposited films at this tem- perature are amorphous. The PLD process was ... For the XPS experiment, an Al anode. X-ray source was employed with a concentric hemispheri- cal analyzer (Specs Company, model EA10 plus) to analyse.

  1. Structural polymorphism in multiferroic BiMnO{sub 3} at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kozlenko, D.P. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Dang, N.T. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Tula State University, Department of Natural Sciences, 300600 Tula (Russian Federation); Jabarov, S.H. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Institute of Physics, ANAS, Baku, AZ 1143 (Azerbaijan); Belik, A.A. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kichanov, S.E., E-mail: [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Lukin, E.V. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Lathe, C. [Helmholtz Centre Potsdam, Telegrafenberg, 14473 Potsdam (Germany); Dubrovinsky, L.S. [Bayerisches Geoinstitute, University Bayreuth, D-95440 Bayreuth (Germany); Kazimirov, V.Yu. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Smirnov, M.B. [Saint-Petersburg State University, Department of Physics, 194508 St-Petersburg (Russian Federation); Savenko, B.N. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation); Mammadov, A.I. [Institute of Physics, ANAS, Baku, AZ 1143 (Azerbaijan); Takayama-Muromachi, E. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Khiem, L.H. [Institute of Physics, Vietnam Academy of Science and Technology, 10000 Hanoi (Viet Nam)


    Highlights: • The detailed P–T phase diagram of BiMnO{sub 3} was established. • We found three monoclinic modifications of BiMnO{sub 3} at pressure and temperature. • A suppression of monoclinic C2/c phase have been observed under pressure. • We found a new orthorhombic Imma phase of BiMnO{sub 3} at P > 20 GPa. -- Abstract: Structural phase transitions in BiMnO{sub 3} were studied by means of energy-dispersive X-ray diffraction in the pressure 0–4 GPa and temperature 300–900 K ranges, and also by means of angle-dispersive X-ray diffraction and Raman spectroscopy at high pressures up to 50 GPa and ambient temperature. The P–T phase diagram of BiMnO{sub 3} was constructed. A suppression of the transition temperatures between monoclinic C2/c and orthorhombic Pnma phases was observed under pressure. The temperature and pressure dependencies of lattice parameters were obtained. A new orthorhombic Imma phase was observed at P > 20 GPa. The lattice dynamics calculations were performed for the analysis of the Raman spectra of BiMnO{sub 3}.

  2. Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor

    Directory of Open Access Journals (Sweden)

    W. A. Cooper


    Full Text Available A new laser air-motion sensor measures the true airspeed with a standard uncertainty of less than 0.1 m s−1 and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the global positioning system, then indicate (via integrations of the hydrostatic equation during climbs and descents that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 °C. For airspeed, pressure and temperature, these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that although the initial calibration of the measured static and dynamic pressures requires a measured temperature, once calibrated these measured pressures and the measurement of airspeed from the new laser air-motion sensor provide a measurement of temperature that does not depend on any other temperature sensor.

  3. Integrated pressure and temperature sensor with high immunity against external disturbance for flexible endoscope operation (United States)

    Maeda, Yusaku; Maeda, Kohei; Kobara, Hideki; Mori, Hirohito; Takao, Hidekuni


    In this study, an integrated pressure and temperature sensor device for a flexible endoscope with long-term stability in in vivo environments was developed and demonstrated. The sensor, which is embedded in the thin wall of the disposable endoscope hood, is intended for use in endoscopic surgery. The device surface is coated with a Cr layer to prevent photoelectronic generation induced by the strong light of the endoscope. The integrated temperature sensor allows compensation for the effect of the temperature drift on a pressure signal. The fabricated device pressure resolution is 0.4 mmHg; the corresponding pressure error is 3.2 mmHg. The packaged device was used in a surgical simulation in an animal experiment. Pressure and temperature monitoring was achieved even in a pH 1 acid solution. The device enables intraluminal pressure and temperature measurements of the stomach, which facilitate the maintenance of internal stomach conditions. The applicability of the sensor was successfully demonstrated in animal experiments.

  4. Evidence for strong enhancement of the magnetic ordering temperature of trivalent Nd metal under extreme pressure (United States)

    Song, J.; Bi, W.; Haskel, D.; Schilling, J. S.


    Four-point electrical resistivity measurements were carried out on Nd metal and dilute magnetic alloys containing up to 1 at.% Nd in superconducting Y for temperatures 1.5-295 K under pressures to 210 GPa. The magnetic ordering temperature To of Nd appears to rise steeply under pressure, increasing ninefold to 180 K at 70 GPa before falling rapidly. Y(Nd) alloys display both a resistivity minimum and superconducting pair breaking Δ Tc as large as 38 K/at.% Nd. The present results give evidence that for pressures above 30-40 GPa, the exchange coupling J between Nd ions and conduction electrons becomes negative, thus activating Kondo physics in this highly correlated electron system. The rise and fall of To and Δ Tc with pressure can be accounted for in terms of an increase in the Kondo temperature.

  5. Versatile setup for optical spectroscopy under high pressure and low temperature (United States)

    Tran, Michaël K.; Levallois, Julien; Akrap, Ana; Teyssier, Jérémie; Kuzmenko, Alexey B.; Lévy-Bertrand, Florence; Tediosi, Riccardo; Brandt, Mehdi; Lerch, Philippe; van der Marel, Dirk


    We present an optical setup for spectroscopic measurements in the infrared and of Raman shift under high pressure and at low temperature. Using a membrane-driven diamond anvil cell, the pressure can be tuned in situ up to 20 GPa and the temperatures ranges from room temperature down to 18 K in transmission mode and 13 K in reflection mode. In transmission, the setup is entirely working under vacuum to reduce the water absorption features and obtain a higher spectral stability. Since the infrared throughput obtained with a thermal source is limited, the use of a synchrotron source allowed to enhance the performance, as illustrated with results obtained with various materials. The analysis of the reflectivity is adapted so that it benefits from ambient pressure data and produces quantitative optical conductivity curves that can be easily compared to the results at ambient pressure.

  6. Effects of pressure and temperature on thermal contact resistance between different materials

    Directory of Open Access Journals (Sweden)

    Zhao Zhe


    Full Text Available To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.

  7. Effects of high hydrostatic pressure and temperature increase on Escherichia coli spp. and pectin methyl esterase inactivation in orange juice. (United States)

    Torres, E F; González-M, G; Klotz, B; Rodrigo, D


    The aim of this study was to evaluate the effect of high hydrostatic pressure treatment combined with moderate processing temperatures (25 ℃-50 ℃) on the inactivation of Escherichia coli O157: H7 (ATCC 700728), E. coli K12 (ATCC 23716), and pectin methyl esterase in orange juice, using pressures of 250 to 500 MPa with times ranging between 1 and 30 min. Loss of viability of E. coli O157:H7 increased significantly as pressure and treatment time increased, achieving a 6.5 log cycle reduction at 400 MPa for 3 min at 25 ℃ of treatment. With regard to the inactivation of pectin methyl esterase, the greatest reduction obtained was 90.05 ± 0.01% at 50 ℃ and 500 MPa of pressure for 15 min; therefore, the pectin methyl esterase enzyme was highly resistant to the treatments by high hydrostatic pressure. The results obtained in this study showed a synergistic effect between the high pressure and moderate temperatures in inactivating E. coli cells. © The Author(s) 2016.

  8. Phenomenology of polymorphism: The topological pressure-temperature phase relationships of the dimorphism of finasteride

    Energy Technology Data Exchange (ETDEWEB)

    Gana, Ines [EAD Physico-chimie Industrielle du Medicament (EA 4066), Faculte de Pharmacie, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75006 Paris (France) and Etablissement pharmaceutique de l' Assistance Publique - Hopitaux de Paris, Agence Generale des Equipements et Produits de Sante, 7 Rue du Fer a moulin, 75005 Paris (France); Ceolin, Rene [EAD Physico-chimie Industrielle du Medicament (EA 4066), Faculte de Pharmacie, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75006 Paris (France); Rietveld, Ivo B., E-mail: [EAD Physico-chimie Industrielle du Medicament (EA 4066), Faculte de Pharmacie, Universite Paris Descartes, 4 Avenue de l' Observatoire, 75006 Paris (France)


    Highlights: Black-Right-Pointing-Pointer The topological pressure-temperature phase diagram for the dimorphism of finasteride. Black-Right-Pointing-Pointer Pressure affects phase equilibria: an enantiotropic phase relationship turning monotropic at high pressure. Black-Right-Pointing-Pointer The influence of pressure on phase behavior inferred from data obtained under ordinary conditions. - Abstract: Knowledge of the phase behavior in the solid state of active pharmaceutical ingredients is important for the development of stable drug formulations. The topological method for the construction of pressure-temperature phase diagrams has been applied to study the phase behavior of finasteride. It is demonstrated that with basic calorimetric measurements and X-ray diffraction sufficient data can be obtained to construct a complete topological pressure-temperature phase diagram. The dimorphism observed for finasteride gives rise to a phase diagram similar to the paradigmatic diagram of sulfur. The solid-solid phase relationship is enantiotropic at ordinary pressure and becomes monotropic at elevated pressure, where solid I is the only stable phase.

  9. Separation Process of Nonpolar Gas Hydrate in Food Solution under High Pressure Apparatus

    Directory of Open Access Journals (Sweden)

    Yohanes Aris Purwanto


    Full Text Available Separation process of nonpolar gas hydrate formation in liquid food was experimentally studied under high pressure container. Xenon (Xe gas was selected as hydrate forming gas and coffee solution was used as a sample of liquid food. The high-pressure stainless steel container having the inner diameter of 60 mm and the volume of 700 mL with a U-shaped stirrer was designed to carry out this experiment. A temperature of 9.0°C and Xe partial pressure of 0.9 MPa were set as a given condition. The experiment was designed to examine the effect of steel screen size, formation rate, temperature condition, and amount of Xe gas dissolving in the solution on the separation process which was indicated by concentration efficiency. Screen size of 200 and 280 mesh resulted in higher concentration efficiency than that of 100 mesh. The higher stirring rate caused the higher formation rate of Xe hydrate and created the smaller Xe hydrate crystals. At the condition giving the same solubility in water, temperature of 14.8°C resulted in lower concentration efficiency than 9.0°C. The increase in the amount of Xe gas dissolving in coffee solution caused the concentration efficiency to decrease; however, the concentration ratio between the final and initial concentration of the solution increased.

  10. Feasibility study of measuring the temperature and pressure of warm dense matter.

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, Patrick K.; Schwarz, Jens


    We have investigated the feasibility of making accurate measurements of the temperature and pressure of solid-density samples rapidly heated by the Z-Petawatt laser to warm dense matter (WDM) conditions, with temperatures approaching 100eV. The study focused specifically on the heating caused by laser generated proton beams. Based on an extensive literature search and numerical investigations, a WDM experiment is proposed which will accurately measure temperature and pressure based on optical emission from the surface and sample expansion velocity.

  11. Temperature and high pressure effects on the structural features of catalytic nanocomposites oxides by Raman spectroscopy (United States)

    da Silva, Antonio N.; Pinto, Raffael C. F.; Freire, Paulo T. C.; Junior, Jose Alves L.; Oliveira, Alcineia C.; Filho, Josué M.


    Structural characterizations of nanostructured oxides were studied by X-ray diffraction (XRD), Raman and infrared spectroscopy. The oxides catalysts namely, SnO2, ZrO2, CeO2, MnOx, Al2O3 and TiO2 were prepared by a nanocasting route and the effect of the temperature and pressure on the stability of the solids was evaluated. Raman spectra showed that ZrO2 and TiO2 exhibited phase transitions at moderate temperatures whereas CeO2, SnO2 and MnOx had an effective creation of defects in their structures upon annealing at elevated temperatures. The results suggested also that the effect of the temperature on the particles growth is related to the type of oxide. In this regard, phase transition by up to 600 °C accelerated the sintering of ZrO2 and CeO2 grains compared to TiO2, SnO2 and MnOx counterparts. Under hydrostatic pressures lower than 10 GPa, rutile TiO2 and tetragonal ZrO2 exhibited pressure induced phase transition whereas CeO2 and SnO2 were stable at pressures close to 15 GPa. The experiments revealed that the nanostructured SnO2 oxide exhibited stable performance at relatively high temperatures without phase transition or sintering, being suitable to be used as catalysts in the range of temperature and pressure studied.

  12. Effects of irradiation at lower temperature on the microstructure of Cr-Mo-V-alloyed reactor pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Grosse, M.; Boehmert, J.; Gilles, R. [Hahn-Meitner-Institut Berlin GmbH (Germany)


    The microstructural damage process due to neutron irradiation [1] proceeds in two stages: - formation of displacement cascades - evolution of the microstructure by defect reactions. Continuing our systematic investigation about the microstructural changes of Russian reactor pressure vessel steel due to neutron irradiation the microstructure of two laboratory heats of the VVER 440-type reactor pressure vessel steel after irradiation at 60 C was studied by small angle neutron scattering (SANS). 60 C-irradiation differently changes the irradiation-induced microstructure in comparison with irradiation at reactor operation temperature and can, thus, provide new insights into the mechanisms of the irradiation damage. (orig.)

  13. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Brinkman, C.R.


    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X.

  14. Thermally induced processes in mixtures of aluminum with organic acids after plastic deformations under high pressure (United States)

    Zhorin, V. A.; Kiselev, M. R.; Roldugin, V. I.


    DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5-4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30-40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.

  15. Inactivation of Byssochlamys nivea ascospores in strawberry puree by high pressure, power ultrasound and thermal processing. (United States)

    Evelyn; Silva, F V M


    Byssochlamys nivea is a mold that can spoil processed fruit products and produce mycotoxins. In this work, high pressure processing (HPP, 600 MPa) and power ultrasound (24 kHz, 0.33 W/mL; TS) in combination with 75°C for the inactivation of four week old B. nivea ascospores in strawberry puree for up to 30 min was investigated and compared with 75°C thermal processing alone. TS and thermal processing can activate the mold ascospores, but HPP-75°C resulted in 2.0 log reductions after a 20 min process. For a 10 min process, HPP-75°C was better than 85°C alone in reducing B. nivea spores (1.4 vs. 0.2 log reduction), demonstrating that a lower temperature in combination with HPP is more effective for spore inactivation than heat alone at a higher temperature. The ascospore inactivation by HPP-thermal, TS and thermal processing was studied at different temperatures and modeled. Faster inactivation was achieved at higher temperatures for all the technologies tested, indicating the significant role of temperature in spore inactivation, alone or combined with other physical processes. The Weibull model described the spore inactivation by 600 MPa HPP-thermal (38, 50, 60, 75°C) and thermal (85, 90°C) processing, whereas the Lorentzian model was more appropriate for TS treatment (65, 70, 75°C). The models obtained provide a useful tool to design and predict pasteurization processes targeting B. nivea ascospores. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Processing of extraterrestrial materials by high temperature vacuum vaporization (United States)

    Grimley, R. T.; Lipschutz, M. E.


    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  17. [The process if teaching-learning in blood pressure monitoring]. (United States)

    Moreira, T M; de Oliveira, T C; de Araújo, T L


    The nurse is considered the professional that obtains more trustworthy data in the measures insinuations of arterial pressure for inducing less reactions of alert in the customer, generating of values falsely high. Even so, a lot of times, she presents spaces in the knowledge of the subject, so much in the technical aspects, as in the anátomo-physiologic ones. That prioritizes the development of teaching strategies, seeking to minimize flaws and to turn the effective learning process. Objectifying to promote the knowledge of the technique of measurement of the arterial pressure close to a research group, it took place a reciclation and avaliation questionnaire of the knowledge of the group was applied before and after the same. The effectiveness of that method was evidenced, because 100% of the sample (nine) they referred contribution for better of the fundamentation theoretical-practice, decreasing difficulties originating from of the verification of the arterial pressure. It is ended that, being the education actions in extremely valid and necessary health, the male nurse, as educator that is, needs to recycle its knowledge and its better techniques continually.

  18. Advanced High-Temperature, High-Pressure Transport Reactor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Swanson


    50 hours of gasification on a petroleum coke from the Hunt Oil Refinery and an additional 73 hours of operation on a high-ash coal from India. Data from these tests indicate that while acceptable fuel gas heating value was achieved with these fuels, the transport gasifier performs better on the lower-rank feedstocks because of their higher char reactivity. Comparable carbon conversions have been achieved at similar oxygen/coal ratios for both air-blown and oxygen-blown operation for each fuel; however, carbon conversion was lower for the less reactive feedstocks. While separation of fines from the feed coals is not needed with this technology, some testing has suggested that feedstocks with higher levels of fines have resulted in reduced carbon conversion, presumably due to the inability of the finer carbon particles to be captured by the cyclones. These data show that these low-rank feedstocks provided similar fuel gas heating values; however, even among the high-reactivity low-rank coals, the carbon conversion did appear to be lower for the fuels (brown coal in particular) that contained a significant amount of fines. The fuel gas under oxygen-blown operation has been higher in hydrogen and carbon dioxide concentration since the higher steam injection rate promotes the water-gas shift reaction to produce more CO{sub 2} and H{sub 2} at the expense of the CO and water vapor. However, the high water and CO{sub 2} partial pressures have also significantly reduced the reaction of (Abstract truncated)

  19. Intelligent Detector of Internal Combustion Engine Cylinder Pressure and Sensitivity Temperature Coefficient Compensation

    Directory of Open Access Journals (Sweden)

    Beirong Zheng


    Full Text Available The detecting device based on mechanical mechanism is far from the measurement of internal combustion engine cylinder explosion and compression pressure. This pressure detection is under the environment of pulsed gas (over 500 times per one minute and mechanical impactive vibration. Piezoresistive detection with silicon on insulator (SOI strain gauges to pressure seems to be a good solution to meet such special applications. In this work, separation by implanted oxygen (SIMOX wafer was used to fabricate the high temperature pressure sensor chip. For high accuracy and wide temperature range application, this paper also presents a novel pressure sensitivity temperature coefficient (TCS compensation method, using integrated constant current network. A quantitative compensation formula is introduced in mathematics. During experiments, the absolute value of the compensated TCS is easy to be 10 × 10−6/°C~100 × 10−6/°C by individual adjustment and calibration of each device’s temperature compensation. Therefore, the feasibility and practicability of this technology are tested. Again, the disadvantages are discussed after the research of the experiment data and the improvement methods are also given in the designing period. This technology exhibits the great potential practical value of internal combustion engine cylinder pressure with volume manufacturing.

  20. Phase changes of filled ice Ih methane hydrate under low temperature and high pressure. (United States)

    Tanaka, Takehiko; Hirai, Hisako; Matsuoka, Takahiro; Ohishi, Yasuo; Yagi, Takehiko; Ohtake, Michika; Yamamoto, Yoshitaka; Nakano, Satoshi; Irifune, Tetsuo


    Low-temperature and high-pressure experiments were performed with filled ice Ih structure of methane hydrate under 2.0-77.0 GPa and 30-300 K using diamond anvil cells and a helium-refrigeration cryostat. In situ X-ray diffractometry revealed distinct changes in the compressibility of the axial ratios of the host framework with pressure. Raman spectroscopy showed a split in the C-H vibration modes of the guest methane molecules, which was previously explained by the orientational ordering of the guest molecules. The pressure and temperature conditions at the split of the vibration modes agreed well with those of the compressibility change. The results indicate the following: (i) the orientational ordering of the guest methane molecules from an orientationally disordered state occurred at high pressures and low temperatures; and (ii) this guest ordering led to anisotropic contraction in the host framework. Such guest orientational ordering and subsequent anisotropic contraction of the host framework were similar to that reported previously for filled ice Ic hydrogen hydrate. Since phases with different guest-ordering manners were regarded as different phases, existing regions of the guest disordered-phase and the guest ordered-phase were roughly estimated by the X-ray study. In addition, above the pressure of the guest-ordered phase, another high-pressure phase developed in the low-temperature region. The deuterated-water host samples were also examined, and the influence of isotopic effects on guest ordering and phase transformation was observed.

  1. Wireless Capacitive Pressure Sensor With Directional RF Chip Antenna for High Temperature Environments (United States)

    Scardelletti, M. C.; Jordan, J. L.; Ponchak, G. E.; Zorman, C. A.


    This paper presents the design, fabrication and characterization of a wireless capacitive pressure sensor with directional RF chip antenna that is envisioned for the health monitoring of aircraft engines operating in harsh environments. The sensing system is characterized from room temperature (25 C) to 300 C for a pressure range from 0 to 100 psi. The wireless pressure system consists of a Clapp-type oscillator design with a capacitive MEMS pressure sensor located in the LC-tank circuit of the oscillator. Therefore, as the pressure of the aircraft engine changes, so does the output resonant frequency of the sensing system. A chip antenna is integrated to transmit the system output to a receive antenna 10 m away.The design frequency of the wireless pressure sensor is 127 MHz and a 2 increase in resonant frequency over the temperature range of 25 to 300 C from 0 to 100 psi is observed. The phase noise is less than minus 30 dBcHz at the 1 kHz offset and decreases to less than minus 80 dBcHz at 10 kHz over the entire temperature range. The RF radiation patterns for two cuts of the wireless system have been measured and show that the system is highly directional and the MEMS pressure sensor is extremely linear from 0 to 100 psi.


    Directory of Open Access Journals (Sweden)



    Full Text Available Temperature dependences of longitudinal and transverse dielectric permeability of KDP and DKDP crystals are studied at different values of hydrostatic pressure in order to determine the pressure behaviour of the isotropic point for these crystals. The isotropic point temperature in KDP crystals at atmospheric pressure is Ti=186 K at the measuring field frequency 1 kHz and Ti=176 K at the frequency of 1 MHz. In DKDP crystals the isotropic point is achieved at the temperature Ti=300 K (1 kHz and Ti=253 K (1 MHz. The hydrostatic pressure increase results in the reduction of the isotropic point temperature with the pressure coefficients ∂Ti / ∂p = -4.3 K/kbar for KDP and ∂ Ti / ∂ p = -2.9 K/kbar for DKDP. The analysis of the experimental results in the framework of the Blinc-Zeks pseudospin formalism has shown a good agreement between the calculated and the experimentally obtained temperature of the isotropic point for KDP crystals.

  3. Advanced High-Temperature, High-Pressure Transport Reactor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Michael Swanson; Daniel Laudal


    . Higher-reactivity (low-rank) coals appear to perform better in a transport reactor than the less reactive bituminous coals. Factors that affect TRDU product gas quality appear to be coal type, temperature, and air/coal ratios. Testing with a higher-ash, high-moisture, low-rank coal from the Red Hills Mine of the Mississippi Lignite Mining Company has recently been completed. Testing with the lignite coal generated a fuel gas with acceptable heating value and a high carbon conversion, although some drying of the high-moisture lignite was required before coal-feeding problems were resolved. No ash deposition or bed material agglomeration issues were encountered with this fuel. In order to better understand the coal devolatilization and cracking chemistry occurring in the riser of the transport reactor, gas and solid sampling directly from the riser and the filter outlet has been accomplished. This was done using a baseline Powder River Basin subbituminous coal from the Peabody Energy North Antelope Rochelle Mine near Gillette, Wyoming.

  4. Monitoring of O2 and temperature in a pelletizing process (United States)

    Sandstroem, Lars G.; Lundqvist, Stefan H.; Andersson, Torbjoern


    We will show the results from a Tunable Diode Laser (TDL) spectrometer installation monitoring the O2 concentration and the temperature in an olivine pellet production plant. The spectrometer has been operating continuously for more than two years. In the pelletizing process a reduction of magnetite and sintering takes place at a temperature around 1250 degree(s)C. To achieve a high and predictable quality of the produced pellets the oxygen concentration and the temperature has to be measured in-situ inside the process furnace. A specially designed high temperature sensor was mounted on the furnace wall and an optical fiber was used to carry the probing light from the TDL spectrometer to the measurement point. The TDL spectrometer operates at two absorption lines in the near infrared wavelength region to measure the oxygen concentration and the temperature simultaneously. The temperature is measured using the relative intensity of the two absorption lines and the concentration is calculated from the temperature compensated absorbance. The accuracy of the concentration and temperature measurements at 1 s response time was 0.1 vol.% and 50 degree(s)C, respectively. In order to validate the TDL measurements the pelletizing process furnace temperature was varied between 100 degree(s)C up to 1300 degree(s)C while the oxygen and temperature readings from the TDL spectrometer was recorded. The temperature measurements were also correlated with temperature measurements using thermocouples inside the furnace. The O2 absorption line parameters were determined in a controlled laboratory experiment using a heated measurement path. This work shows that it is possible to build and field a TDL spectrometer to measure O2 and temperature in-situ in a steel making process furnace.

  5. Creep of Posidonia and Bowland shale at elevated pressures and temperatures (United States)

    Herrmann, Johannes; Rybacki, Erik; Sone, Hiroki; Dresen, Georg


    The fracture-healing rate of artificial cracks generated by hydraulic fracturing is of major interest in the E&P industry since it is important for the long-time productivity of a well. To estimate the stress-induced healing rate of unconventional reservoir rocks, we performed deformation tests on Bowland shale rocks (UK) and on Posidonia shales (Germany). Samples of 1cm diameter and 2cm length were drilled perpendicular to the bedding and deformed in a high pressure, high temperature deformation apparatus. Constant strain rate tests at 5*10-4*s-1, 50 MPa confining pressure and 100˚ C temperature reveal a mainly brittle behaviour with predominantly elastic deformation before failure and high strength of low porosity (˜2%), quartz-rich (˜42 vol%) Bowland shale. In contrast, the low porosity (˜3%), carbonate- (˜43 vol%) and clay-rich (˜33 vol%) Posidonia shale deforms semi-brittle with pronounced inelastic deformation and low peak strength. These results suggest a good fracability of the Bowland formation compared to the Posidonia shale. Constant load (creep) experiments performed on Bowland shale at 100˚ C temperature and 75 MPa pressure show mainly transient (primary) deformation with increasing strain rate at increasing axial stress. The strain rate increases also with increasing temperature, measured in the range of 75 - 150˚ C at fixed stress and confinement. In contrast, increasing confining pressure (from 30 to 115 MPa) at given temperature and stress results in decreasing strain rate. In contrast, Posidonia shale rocks are much more sensitive to changes in stress, temperature and pressure than Bowland shale. Empirical relations between strain and stress that account for the influence of pressure and temperature on creep properties of Posidonia and Bowland shale rocks can be used to estimate the fracture healing rate of these shales under reservoir conditions.

  6. An in situ synchrotron XAS methodology for surface analysis under high temperature, pressure, and shear (United States)

    Dorgham, A.; Neville, A.; Ignatyev, K.; Mosselmans, F.; Morina, A.


    The complex tribochemical nature of lubricated tribological contacts is inaccessible in real time without altering their initial state. To overcome this issue, a new design of a pin-on-disc tribological apparatus was developed and combined with synchrotron X-ray absorption spectroscopy (XAS). Using the designed apparatus, it is possible to study in situ the transient decomposition reactions of various oil additives on different surfaces under a wide range of realistic operating conditions of contact pressure (1.0-3.0 GPa), temperature (25-120 °C), and sliding speed (30-3000 rpm or 0.15-15 m/s). To test the apparatus, several tribological tests were performed at different shearing times ranging from 2.5 to 60 min. These tests were carried out under helium atmosphere at a temperature of 80 °C, contact pressure of 2.2 GPa, and sliding speed of 50 rpm. The XAS experiments indicate that the zinc dialkyldithiophosphate antiwear additive decomposes in the oil to form a tribofilm on the iron surface at different reaction kinetics from the ones of the thermal film. The tribofilm composition evolves much faster than the one of the thermal film, which confirms that the formation of the tribofilm is a thermally activated process similar to the one of the thermal film but accelerated by shear. Furthermore, the results indicate that the sulfur of the formed film, whether a tribofilm or a thermal film, appears initially in the form of sulfate, with some sulfide, which under heat or shear is reduced into mainly sulfide.

  7. Embedded optical probes for simultaneous pressure and temperature measurement of materials in extreme conditions (United States)

    Sandberg, R. L.; Rodriguez, G.; Gibson, L. L.; Dattelbaum, D. M.; Stevens, G. D.; Grover, M.; Lalone, B. M.; Udd, E.


    We present recent efforts at Los Alamos National Laboratory (LANL) to develop sensors for simultaneous, in situ pressure and temperature measurements under dynamic conditions by using an all-optical fiber-based approach. While similar tests have been done previously in deflagration-to-detonation tests (DDT), where pressure and temperature were measured to 82 kbar and 400°C simultaneously, here we demonstrate the use of embedded fiber grating sensors to obtain high temporal resolution, in situ pressure measurements in inert materials. We present two experimental demonstrations of pressure measurements: (1) under precise shock loading from a gas-gun driven plate impact and (2) under high explosive driven shock in a water filled vessel. The system capitalizes on existing telecom components and fast transient digitizing recording technology. It operates as a relatively inexpensive embedded probe (single-mode 1550 nm fiber-based Bragg grating) that provides a continuous fast pressure record during shock and/or detonation. By applying well-controlled shock wave pressure profiles to these inert materials, we study the dynamic pressure response of embedded fiber Bragg gratings to extract pressure amplitude of the shock wave and compare our results with particle velocity wave profiles measured simultaneously.

  8. Low-temperature resonant Raman asymmetry in 2H-MoS2 under high pressure (United States)

    Livneh, Tsachi; Reparaz, Juan S.; Goñi, Alejandro R.


    We report on the combined effect of temperature (6 K–300 K) and high pressure (up to 6 GPa) on the resonant Raman scattering by A1g phonons in bulk 2H-MoS2, as the energy of the A exciton is tuned into resonance with an exciting laser at EL  =  1.96 eV. As expected, the pressure to be applied for attaining resonant conditions decreases with decreasing temperature. A striking result concerns the combined effect of temperature and pressure on the strength of the incoming relative to the outgoing resonance of the A1g phonon. When its Raman intensity is normalized by that of the ‘non-resonant’ E2g1 phonon (IA1g/IE2g1 ), we find that the contribution of the pressure-tuned outgoing resonance relative to that of the incoming channel changes with temperature. At room temperature both contributions are about equal, as expected. Interestingly, with decreasing temperature an asymmetry in the relative magnitude of the resonances develops, becoming the outgoing contribution about half of the incoming resonance below ~50 K. We discuss the different possibilities for the origin of this effect.

  9. High Temperature, High Pressure Devices for Zonal Isolation in Geothermal Wells

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Paul [Composite Technology Development, Inc, Lafayette, CO (United States)


    The U.S. Department of Energy is leading the development of alternative energy sources that will ensure the long-term energy independence of our nation. One key renewable resource being advanced is geothermal energy which offers an environmentally benign, reliable source of energy for the nation. To utilize this resource, water will be introduced into wells 3 to 10 km deep to create a geothermal reservoir. This approach is known as an Enhanced Geothermal System (EGS). The high temperatures and pressures at these depths have become a limiting factor in the development of this energy source. For example, reliable zonal isolation for high-temperature applications at high differential pressures is needed to conduct mini-fracs and other stress state diagnostics. Zonal isolation is essential for many EGS reservoir development activities. To date, the capability has not been sufficiently demonstrated to isolate sections of the wellbore to: 1) enable stimulation; and 2) seal off unwanted flow regions in unknown EGS completion schemes and high-temperature (>200°C) environments. In addition, packers and other zonal isolation tools are required to eliminate fluid loss, to help identify and mitigate short circuiting of flow from injectors to producers, and to target individual fractures or fracture networks for testing and validating reservoir models. General-purpose open-hole packers do not exist for geothermal environments, with the primary barrier being the poor stability of elastomeric seals at high temperature above 175°C. Experimental packer systems have been developed for geothermal environments but they currently only operate at low pressure, they are not retrievable, and they are not commercially available. The development of the high-temperature, high-pressure (HTHP) zonal isolation device would provide the geothermal community with the capability to conduct mini-fracs, eliminate fluid loss, to help identify and mitigate short circuiting of flow from injectors to

  10. System and process for capture of acid gasses at elevated pressure from gaseous process streams (United States)

    Heldebrant, David J.; Koech, Phillip K.; Linehan, John C.; Rainbolt, James E.; Bearden, Mark D.; Zheng, Feng


    A system, method, and material that enables the pressure-activated reversible chemical capture of acid gasses such as CO.sub.2 from gas volumes such as streams, flows or any other volume. Once the acid gas is chemically captured, the resulting product typically a zwitterionic salt, can be subjected to a reduced pressure whereupon the resulting product will release the captures acid gas and the capture material will be regenerated. The invention includes this process as well as the materials and systems for carrying out and enabling this process.

  11. Method development for compensating temperature effects in pressure sensitive paint measurements (United States)

    Demandante, Carlo Greg N.


    Pressure sensitive luminescent paints (PSP) have recently emerged as a viable technique for aerodynamic pressure measurements. The technique uses a surface coating which contains probe molecules that luminesce when excited by light of an appropriate wavelength. The photoluminescence of these materials is known to be quenched by the presence of molecular oxygen. Since oxygen is a fixed mole fraction of the air, the coating's luminescence intensity varies inversely with air pressure. Digital imaging of the luminescence varying across a coated surface produces a pressure distribution map over that surface. One difficulty encountered with this technique is the temperature effect on the luminescence intensity. Present PSP formulations have significant sensitivity to temperature. At the moment, the most practical way of correcting for temperature effects is to calibrate the paint in place at the operating temperatures by using a few well-placed pressure taps. This study is looking at development of temperature indicating coatings that can be applied and measured concurrently with PSP, and use the temperature measurement to compute the correct pressure. Two methods for this dual paint formulation are proposed. One method will use a coating that consists of temperature sensitive phosphors in a polymer matrix. This is similar in construction to PSP, except that the probe molecules used are selected primarily for their temperature sensitivity. Both organic phosphors (e.g., europium thenoyltrifluoroacetonate, bioprobes) and inorganic phosphors (e.g., Mg4(F)GeO6:Mn, La2O2S:Eu, Radelin Type phosphors, Sylvania Type phosphors) will be evaluated for their temperature sensing potential. The next method will involve a novel coating composing of five membered heterocyclic conducting polymers which are known to show temperature dependent luminescence (e.g., poly(3-alkylthiopene), poly(3-alkylselenophene), poly(3-alkylfuran)). Both methods will involve applying a bottom layer of

  12. Experimental and numerical study of heterogeneous pressure-temperature-induced lethal and sublethal injury of Lactococcus lactis in a medium scale high-pressure autoclave. (United States)

    Kilimann, K V; Kitsubun, P; Delgado, A; Gänzle, M G; Chapleau, N; Le Bail, A; Hartmann, C


    The present contribution is dedicated to experimental and theoretical assessment of microbiological process heterogeneities of the high-pressure (HP) inactivation of Lactococcus lactis ssp. cremoris MG 1363. The inactivation kinetics are determined in dependence of pressure, process time, temperature and absence or presence of co-solutes in the buffer system namely 4 M sodium chloride and 1.5 M sucrose. The kinetic analysis is carried out in a 0.1-L autoclave in order to minimise thermal and convective effects. Upon these data, a deterministic inactivation model is formulated with the logistic equation. Its independent variables represent the counts of viable cells (viable but injured) and of the stress-resistant cells (viable and not injured). This model is then coupled to a thermo-fluiddynamical simulation method, high-pressure computer fluid dynamics technique (HP-CFD), which yields spatiotemporal temperature and flow fields occurring during the HP application inside any considered autoclave. Besides the thermo-fluiddynamic quantities, the coupled model predicts also the spatiotemporal distribution of both viable (VC) and stress-resistant cell counts (SRC). In order to assess the process non-uniformity of the microbial inactivation in a 3.3-L autoclave experimentally, microbial samples are placed at two distinct locations and are exposed to various process conditions. It can be shown with both, experimental and theoretical models that thermal heterogeneities induce process non-uniformities of more than one decimal power in the counts of the viable cells at the end of the treatment. (c) 2006 Wiley Periodicals, Inc.

  13. H2O and CO2 vapor pressure measurements at temperatures relevant to the middle atmosphere of Earth and Mars (United States)

    Nachbar, M.; Duft, D.; Leisner, T.


    Measurements of the vapor pressure of H2O and CO2 at temperatures relevant to the middle atmosphere of Earth and Mars are rare but important in order to describe cloud formation and ice particle growth processes. In this contribution we present a novel technique for measuring the vapor pressure of condensable gases by analyzing the depositional growth rates on free nanoparticles at high supersaturation. The method is applied to measure the vapor pressure of CO2 between 75K and 85K. By comparison with previous measurements and parameterizations we are able to show the excellent functionality of the method. In addition, the method is used to measure the vapor pressure over H2O ice between 135K and 160K. We show that the vapor pressure of so called stacking disordered ice Isd deposited at temperatures below 160K is significantly higher compared to hexagonal ice Ih. The consequences for ice cloud formation in the atmosphere of Earth and Mars will be discussed.

  14. An organic cosmo-barometer: Distinct pressure and temperature effects for methyl substituted polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, Wren; Watson, Jonathan S.; Sephton, Mark A., E-mail: [Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London SW7 2AZ (United Kingdom)


    There are a number of key structures that can be used to reveal the formation and modification history of organic matter in the cosmos. For instance, the susceptibility of organic matter to heat is well documented and the relative thermal stabilities of different isomers can be used as cosmothermometers. Yet despite being an important variable, no previously recognized organic marker of pressure exists. The absence of a pressure marker is unfortunate considering our ability to effectively recognize extraterrestrial organic structures both remotely and in the laboratory. There are a wide variety of pressures in cosmic settings that could potentially be reflected by organic structures. Therefore, to develop an organic cosmic pressure marker, we have used state-of-the-art diamond anvil cell (DAC) and synchrotron-source Fourier transform infrared (FTIR) spectroscopy to reveal the effects of pressure on the substitution patterns for representatives of the commonly encountered methyl substituted naphthalenes, specifically the dimethylnaphthalenes. Interestingly, although temperature and pressure effects are concordant for many isomers, pressure appears to have the opposite effect to heat on the final molecular architecture of the 1,5-dimethylnaphthalene isomer. Our data suggest the possibility of the first pressure parameter or 'cosmo-barometer' (1,5-dimethylnaphthalene/total dimethylnaphthalenes) that can distinguish pressure from thermal effects. Information can be obtained from the new pressure marker either remotely by instrumentation on landers or rovers or directly by laboratory measurement, and its use has relevance for all cases where organic matter, temperature, and pressure interplay in the cosmos.

  15. Comparison of Diesel Spray Combustion in Different High-temperature, High-pressure Facilities

    DEFF Research Database (Denmark)

    Pickett, Lyle M.; Genzale, Caroline L.; Bruneaux, Gilles


    Diesel spray experimentation at controlled high-temperature and high-pressure conditions is intended to provide a more fundamental understanding of diesel combustion than can be achieved in engine experiments. This level of understanding is needed to develop the high-fidelity multi-scale CFD models...... boundary conditions at these unique facilities. Performing experiments at the same high-temperature, high-pressure operating conditions is an objective of the Engine Combustion Network (, which seeks to leverage the research capabilities and advanced diagnostics of all...... that will be used to optimize future engine designs. Several spray chamber facilities capable of high-temperature, high-pressure conditions typical of engine combustion have been developed, but because of the uniqueness of each facility, there are uncertainties about their operation. For this paper, we describe...

  16. Solubility Measurements and Modeling of Zinc, Lead and Iron Sulfides at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

    task. Consequently existing data are rare and scattered. The aim of this work is to develop a reliable experimental procedure and to measure solubility of sulfides at high temperature and pressures. Additionally the experimental data are used for estimation of the solid-liquid equilibrium using...... the Extended UNIQUAC model. The experimental determination of the solubility of ZnS, PbS and FeS is carried out at temperatures up to 200°C and pressures up to 60 bars. The minerals in their pure form are added to ultra-pure water previously degassed with nitrogen. The aqueous solution is prepared in a reduced...... oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP...

  17. Effect of hydrostatic pressure on the stress strain behavior of potassium and lead at liquid nitrogen temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chua, J.O.


    The hypothesis that at low homologous temperature, the pressure effect on the yielding of metals is closely related to the effect of pressure on the elastic constants was tested. An apparatus in which tension tests can be made at liquid nitrogen temperature and high hydrostatic pressure was designed and constructed. Tension tests for potassium and lead were carried out at liquid nitrogen temperature and as a function of pressure up to 5.15 kbars. The results show that the effect of hydrostatic pressure was to raise the stress strain curves of both potassium and lead at liquid nitrogen temperature.

  18. Triple rotary gas lock seal system for transferring coal continuously into, or ash out of, a pressurized process vessel

    Energy Technology Data Exchange (ETDEWEB)

    Enright, F.J.; Seidl, R.M.


    A multiple rotary gas lock apparatus using a buffer seal gas is disclosed to enable the transfer of solid materials into or out of a pressurized process containing high temperature, flammable or toxic gases. The buffer seal gas, has a pressure higher than the process pressure and is introduced between two series connected gas locks; this prevents process gas backflow to the feed system. Buffer seal leakage gas from the first pair of gas locks and air from a third gas lock are removed from an opening in a connection between the pair of gas locks and the third gas lock at subatmospheric pressure. This system enables control and usuage of toxic or flammable gases as a buffer for mixing compatibility with the process gas when a suitable inert gas is not available. It also prevents the flow of any toxic gas to the worker environment.

  19. Normalized Temperature Contrast Processing in Infrared Flash Thermography (United States)

    Koshti, Ajay M.


    The paper presents further development in normalized contrast processing used in flash infrared thermography method. Method of computing normalized image or pixel intensity contrast, and normalized temperature contrast are provided. Methods of converting image contrast to temperature contrast and vice versa are provided. Normalized contrast processing in flash thermography is useful in quantitative analysis of flash thermography data including flaw characterization and comparison of experimental results with simulation. Computation of normalized temperature contrast involves use of flash thermography data acquisition set-up with high reflectivity foil and high emissivity tape such that the foil, tape and test object are imaged simultaneously. Methods of assessing other quantitative parameters such as emissivity of object, afterglow heat flux, reflection temperature change and surface temperature during flash thermography are also provided. Temperature imaging and normalized temperature contrast processing provide certain advantages over normalized image contrast processing by reducing effect of reflected energy in images and measurements, therefore providing better quantitative data. Examples of incorporating afterglow heat-flux and reflection temperature evolution in flash thermography simulation are also discussed.

  20. High temperature heat exchange: nuclear process heat applications

    Energy Technology Data Exchange (ETDEWEB)

    Vrable, D.L.


    The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment.

  1. Experimental permeability studies at elevated temperature and pressure of granitic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Potter, J.M.


    Permeability of quartz monzonite from the Los Alamos hot-dry-rock geothermal well GT-2 was experimentally measured as a function of pressure and temperature. Permeability of the GT-2 rocks from depths of 8580 ft and 9522 ft behaves like Westerly granite for changes in effective confining pressure. However, permeability of these rocks behaves much differently with increasing temperature. As temperature is increased, the permeability of Westerly granite passes through a slight minimum and then increases exponentially above 100/sup 0/C. Upon cooling the permeability shows a permanent increase of up to four times its original value. The permeability of GT-2-9522', on the other hand, drops off exponentially with increasing temperature, reaching a minimum near 140/sup 0/C; above 150/sup 0/C, permeability rises slowly. These changes in permeability with temperature are postulated to be caused by differential thermal expansion (DTE), a phenomena related to the anisotropic and inhomogeneous coefficients of thermal expansion of the mineral grains in the rock. Scanning electron photomicrographs of unheated and heated samples of Westerly and GT-2 rocks support the DTE hypothesis. Differences in the behavior of these rocks with temperature are believed to be due to the respective temperature and pressure environments in which they became equilibrated, since both GT-2 rocks had existed at moderately high temperatures and pressures for some time. Temperature disequilibrium of the GT-2 rocks in their present in situ environments is believed to have caused the differences in the behavior between the two samples and may provide a method for determining the pre-intrusion geothermal gradient of the Jemez area. Flow channels were observed in GT-2 samples using radioactive tracer techniques. Several radioactive isotopes were tried in these experiments, including /sup 22/Na, /sup 63/Ni, and /sup 35/S.

  2. High-Pressure and High-Temperature Sorption of Methane on Black Shales (United States)

    Gasparik, Matus; Ghanizadeh, Amin; Gensterblum, Yves; Weniger, Phillipp; Krooss, Bernhard


    Improved estimations of Gas-In-Place (GIP) for shale gas reservoirs require reliable experimental sorption data for high pressures and high temperatures. In the framework of European Shale Gas Research project (GASH, a manometric method was used to measure methane sorption isotherms on various shales from Europe and the USA. Established procedures originally developed for CBM research were modified to: (1) improve the accuracy of sorption measurements for materials with low sorption capacity (5-10% of that for coals) and (2) extend the experimental conditions to pressures and temperatures representative of shale gas reservoirs. It is generally assumed that at high temperatures (> 100°) sorption does no longer contribute significantly to the total gas storage capacity of shales. Experimental data on high-temperature / high-pressure sorption are, however, still missing. Part of our work was therefore focused on providing reliable experimental data at pressures up to 25 MPa and temperatures up to 150°C. Moisture content has a strong effect on gas sorption capacity due to competition of methane and water molecules for sorption sites and/or pore restrictions in the presence of water. However, sorption measurements on moist samples at different temperatures pose some experimental difficulties. A simple and effective method was developed allowing for measurements of multiple isotherms at constant moisture content in the system. This procedure ensures that the moisture state of the sample remains unchanged and is not affected by evacuation cycles as in conventional measurements. Uncertainties in assessing the temperature dependence of sorption isotherms on moist samples can thus be significantly reduced. The following aspects analyzed in this study will be discussed: • Variation of methane sorption capacity with Total Organic Carbon (TOC) content, mineralogy and thermal maturity • Temperature dependence of methane sorption capacity over a wide

  3. Probabilistic Fracture Mechanics Analysis of Boling Water Reactor Vessel for Cool-Down and Low Temperature Over-Pressurization Transients

    Directory of Open Access Journals (Sweden)

    Jeong Soon Park


    Full Text Available The failure probabilities of the reactor pressure vessel (RPV for low temperature over-pressurization (LTOP and cool-down transients are calculated in this study. For the cool-down transient, a pressure–temperature limit curve is generated in accordance with Section XI, Appendix G of the American Society of Mechanical Engineers (ASME code, from which safety margin factors are deliberately removed for the probabilistic fracture mechanics analysis. Then, sensitivity analyses are conducted to understand the effects of some input parameters. For the LTOP transient, the failure of the RPV mostly occurs during the period of the abrupt pressure rise. For the cool-down transient, the decrease of the fracture toughness with temperature and time plays a main role in RPV failure at the end of the cool-down process. As expected, the failure probability increases with increasing fluence, Cu and Ni contents, and initial reference temperature-nil ductility transition (RTNDT. The effect of warm prestressing on the vessel failure probability for LTOP is not significant because most of the failures happen before the stress intensity factor reaches the peak value while its effect reduces the failure probability by more than one order of magnitude for the cool-down transient.

  4. Pressure dependent low temperature kinetics for CN + CH3CN: competition between chemical reaction and van der Waals complex formation. (United States)

    Sleiman, Chantal; González, Sergio; Klippenstein, Stephen J; Talbi, Dahbia; El Dib, Gisèle; Canosa, André


    The gas phase reaction between the CN radical and acetonitrile CH3CN was investigated experimentally, at low temperatures, with the CRESU apparatus and a slow flow reactor to explore the temperature dependence of its rate coefficient from 354 K down to 23 K. Whereas a standard Arrhenius behavior was found at T > 200 K, indicating the presence of an activation barrier, a dramatic increase in the rate coefficient by a factor of 130 was observed when the temperature was decreased from 168 to 123 K. The reaction was found to be pressure independent at 297 K unlike the experiments carried out at 52 and 132 K. The work was complemented by ab initio transition state theory based master equation calculations using reaction pathways investigated with highly accurate thermochemical protocols. The role of collisional stabilization of a CNCH3CN van der Waals complex and of tunneling induced H atom abstractions were also considered. The experimental pressure dependence at 52 and 132 K is well reproduced by the theoretical calculations provided that an anharmonic state density is considered for the van der Waals complex CH3CNCN and its Lennard-Jones radius is adjusted. Furthermore, these calculations indicate that the experimental observations correspond to the fall-off regime and that tunneling remains small in the low-pressure regime. Hence, the studied reaction is essentially an association process at very low temperature. Implications for the chemistry of interstellar clouds and Titan are discussed.

  5. Liquid Oxygen Liquid Acquisition Device Bubble Point Tests with High Pressure LOX at Elevated Temperatures (United States)

    Jurns, John M.; Hartwig, Jason W.


    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. The present work reports on testing with liquid oxygen (LOX) at elevated pressures (and thus temperatures) (maximum pressure 1724 kPa and maximum temperature 122K) as part of NASA s continuing cryogenic LAD development program. These tests evaluate LAD performance for LOX stored in higher pressure vessels that may be used in propellant systems using pressure fed engines. Test data shows a significant drop in LAD bubble point values at higher liquid temperatures, consistent with lower liquid surface tension at those temperatures. Test data also indicates that there are no first order effects of helium solubility in LOX on LAD bubble point prediction. Test results here extend the range of data for LOX fluid conditions, and provide insight into factors affecting predicting LAD bubble point pressures.

  6. Magnetic and Structural Phase Transitions in Thulium under High Pressures and Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, Yogesh K.; Tsoi, Georgiy M.; Samudrala, Gopi K. [UAB


    The nature of 4f electrons in many rare earth metals and compounds may be broadly characterized as being either "localized" or "itinerant", and is held responsible for a wide range of physical and chemical properties. The pressure variable has a very dramatic effect on the electronic structure of rare earth metals which in turn drives a sequence of structural and magnetic transitions. We have carried out four-probe electrical resistance measurements on rare earth metal Thulium (Tm) under high pressures to 33 GPa and low temperatures to 10 K to monitor the magnetic ordering transition. These studies are complemented by angle dispersive x-ray diffraction studies to monitor crystallographic phase transitions at high pressures and low temperatures. We observe an abrupt increase in magnetic ordering temperature in Tm at a pressure of 17 GPa on phase transition from ambient pressure hcp-phase to α-Sm phase transition. In addition, measured equation of state (EOS) at low temperatures show anomalously low thermal expansion coefficients likely linked to magnetic transitions.

  7. Magnetic and Structural Phase Transitions in Thulium under High Pressures and Low Temperatures (United States)

    Vohra, Yogesh K.; Tsoi, Georgiy M.; Samudrala, Gopi K.


    The nature of 4f electrons in many rare earth metals and compounds may be broadly characterized as being either “localized” or “itinerant”, and is held responsible for a wide range of physical and chemical properties. The pressure variable has a very dramatic effect on the electronic structure of rare earth metals which in turn drives a sequence of structural and magnetic transitions. We have carried out four-probe electrical resistance measurements on rare earth metal Thulium (Tm) under high pressures to 33 GPa and low temperatures to 10 K to monitor the magnetic ordering transition. These studies are complemented by angle dispersive x-ray diffraction studies to monitor crystallographic phase transitions at high pressures and low temperatures. We observe an abrupt increase in magnetic ordering temperature in Tm at a pressure of 17 GPa on phase transition from ambient pressure hcp-phase to α-Sm phase transition. In addition, measured equation of state (EOS) at low temperatures show anomalously low thermal expansion coefficients likely linked to magnetic transitions.

  8. Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection. (United States)

    Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K


    A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Dureja, A.K., E-mail: [Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Sinha, S.K.; Srivastava, Ankit; Sinha, R.K. [Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Chakravartty, J.K. [Materials' Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Seshu, P.; Pawaskar, D.N. [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 76 (India)


    Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 deg. C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce's correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.

  10. Probing the local, electronic and magnetic structure of matter under extreme conditions of temperature and pressure

    DEFF Research Database (Denmark)

    Torchio, R.; Boccato, S.; Cerantola, V.


    In this paper we present recent achievements in the field of investigation of the local, electronic and magnetic structure of the matter under extreme conditions of pressure and temperature. These results were obtained thanks to the coupling of a compact laser heating system to the energy......-dispersive XAS technique available on the ID24 beamline at the ESRF synchrotron. The examples chosen concern the melting and the liquid structure of 3d metals and alloys under high pressures (HPs) and the observation of temperature-induced spin crossover in FeCO3 at HP....



    Flouquet, J.; Haen, P.; HOLTZBERG, F; Lapierre, F.; Mignot, Jean; Ribault, M.; Tournier, R.


    Resistivity measurements of a nearly stoichiometric sample up to 6 kbar and down to 25 mK are reported. For 6 kbar, the resistivity ρ rises up to 120 mΩ.cm at 30 mK whereas just above the ordering temperature TN at 4.2 K its value is 1.65 mΩ.cm. The increase of ρ is exponential with the pressure at very low temperature and linear in the vicinity of TN. Comparisons are made with the pressure dependence of the sublattice magnetization measured by neutron diffraction and with resistivity of othe...

  12. High pressure and temperature deformation experiments on San Carlos olivine and implications for upper mantle anisotropy (United States)

    Shekhar, Sushant; Frost, Daniel J.; Walte, Nicolas; Miyajima, Nobuyoshi; Heidelbach, Florian


    through slip of the [001] slip on the {0hk} plane. These observations can be interpreted as resulting from the progressive hardening of [100] slip with respect to [001] slip with increasing pressure. TEM observations have been made on several of the recovered samples in order to correlate the developed CPO with the action of specific dislocations. Samples deformed at 8 GPa and 1200° C show straight edge dislocations in the plane normal to the diffraction vector, g: 004. Whereas, experiments performed at 1400° C and 8 GPa resulted in very few visible subgrains in the SEM orientation contrast image and only very weak CPO could be observed. TEM study on this sample shows that [001] & [100] edge dislocations were co-activated in climb-configuration which resulted in no perceptible CPO. These results lead us to believe that the transition that occurs between a-slip to c-slip with increasing pressure is rather a gradual process. On the other hand our results imply that at depths over 250 km in the upper mantle, temperatures may be high enough to reinitiate [100] slip. Co-activation of both a-slip and c-slip will not lead to any CPO and the mantle will become seismically isotropic in this scenario. This might be the reason for isotropic behavior of mantle below 250 km depth.



    Miriam Solgajová; Helena Frančáková; Štefan Dráb; Žigmund Tóth


    Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wo...

  14. Process for Forming a High Temperature Single Crystal Canted Spring (United States)

    DeMange, Jeffrey J (Inventor); Ritzert, Frank J (Inventor); Nathal, Michael V (Inventor); Dunlap, Patrick H (Inventor); Steinetz, Bruce M (Inventor)


    A process for forming a high temperature single crystal canted spring is provided. In one embodiment, the process includes fabricating configurations of a rapid prototype spring to fabricate a sacrificial mold pattern to create a ceramic mold and casting a canted coiled spring to form at least one canted coil spring configuration based on the ceramic mold. The high temperature single crystal canted spring is formed from a nickel-based alloy containing rhenium using the at least one coil spring configuration.

  15. Precise electrical transport measurements by using Bridgman type pressure cell at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, Takayuki [Division of Civil and Enviromental Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Ohashi, Masashi [Faculty of Environmental Design, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan)


    We report a technique for the precise measurement of the electrical resisivity under high pressure at low temperature by using Bridgman anvils made of tungsten carbide. Quasi-hydrostatic pressure is generated up to {approx}15 GPa in the relatively large working space which allows the use of large specimens and simple experimental procedures rather than using a standard diamond anvil cell. The application is demonstrated by the measurements of the electrical resistivity of lead in order to describe the effect of pressure on the superconducting transition.

  16. The topological pressure-temperature phase diagram of fluoxetine nitrate: monotropy unexpectedly turning into enantiotropy (United States)

    Céolin, René; Rietveld, Ivo B.


    The phase behavior of pharmaceuticals is important for regulatory requirements and dosage form development. Racemic fluoxetine nitrate possesses two crystalline forms for which initial measurements indicated that they have a monotropic relationship with form I the only stable form. By constructing the topological pressure-temperature phase diagram, it has been shown that unexpectedly form II has a stable domain in the phase diagram and can be easily obtained by heating and grinding. The pressure necessary to obtain form II is only 11 MPa, which is much lower than most pressure used for tableting in the pharmaceutical industry.

  17. Thermoelectric properties of PbTe prepared at high pressure and high temperature

    CERN Document Server

    Zhu, P W; Jia, X; Ma, H A; Ren, G Z; Guo, W L; Zhang, W; Zou Guang Tian


    Lead telluride (PbTe) with rock-salt structure was successfully obtained by a high-pressure and high-temperature (HPHT) method. The orientation of the PbTe samples varies with pressure increase. The results - a decrease in the Seebeck coefficient, resistivity and thermal conductivity of PbTe with pressure but an increase in the thermoelectric power figure sigma S sup 2 - indicate that the figure of merit Z of PbTe samples can be improved several times over by using HPHT.

  18. Pressure drop and temperature rise in He II flow in round tubes, Venturi flowmeters and valves (United States)

    Walstrom, P. L.; Maddocks, J. R.


    Pressure drops in highly turbulent He II flow were measured in round tubes, valves, and Venturi flowmeters. Results are in good agreement with single-phase flow correlations for classical fluids. The temperature rise in flow in a round tube was measured, and found to agree well with predictions for isenthalpic expansion. Cavitation was observed in the venturis under conditions of low back pressure and high flow rate. Metastable superheating of the helium at the venturi throat was observed before the helium made a transition to saturation pressure.

  19. Tensile and Fatigue Behavior of ASS304 for Cold Stretching Pressure Vessels at Cryogenic Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon Seok [The 5th R and D Institute, Agency for Defense Development, Daejeon (Korea, Republic of); Kim, Jae Hoon; Na, Seong Hyun [Chungnam National Univ., Daejon (Korea, Republic of); Lee, Youn Hyung [Korean Gas Safety Corporation, Chungju (Korea, Republic of); Kim, Sung Hun [Daechang Solution Co. Ltd, Busan (Korea, Republic of); Kim, Young Kyun; Kim, Ki Dong [Korean Gas Corporation, R and D Division, Ansan (Korea, Republic of)


    Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress σk. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM)

  20. Time-resolved detection of temperature, concentration, and pressure in a shock tube by intracavity absorption spectroscopy (United States)

    Fjodorow, Peter; Fikri, Mustapha; Schulz, Christof; Hellmig, Ortwin; Baev, Valery M.


    In this paper, we demonstrate the first application of intracavity absorption spectroscopy (ICAS) for monitoring species concentration, total pressure, and temperature in shock-tube experiments. ICAS with a broadband Er3+-doped fiber laser is applied to time-resolved measurements of absorption spectra of shock-heated C2H2. The measurements are performed in a spectral range between 6512 and 6542 cm-1, including many absorption lines of C2H2, with a time resolution of 100 µs and an effective absorption path length of 15 m. Up to 18-times increase of the total pressure and a temperature rise of up to 1200 K have been monitored. Due to the ability of simultaneously recording many absorption lines in a broad spectral range, the presented technique can also be applied to multi-component analysis of transient single-shot processes in reactive gas mixtures in shock tubes, pulse detonation engines, or explosions.

  1. Acetone photophysics at 282 nm excitation at elevated pressure and temperature. II: Fluorescence modeling (United States)

    Hartwig, Jason; Raju, Mandhapati; Sung, Chih-Jen


    This is the second in a series of two papers that presents an updated fluorescence model and compares with the new experimental data reported in the first paper, as well as the available literature data, to extend the range of acetone photophysics to elevated pressure and temperature conditions. This work elucidates the complete acetone photophysical model in terms of each and every competing radiative and non-radiative rate. The acetone fluorescence model is then thoroughly examined and optimized based on disparity with recently conducted elevated pressure and temperature photophysical calibration experiments. The current work offers insight into the competition between non-radiative and vibrational energy decay rates at elevated temperature and pressure and proposes a global optimization of model parameters from the photophysical model developed by Thurber (Acetone Laser-Induced Fluorescence for Temperature and Multiparameter Imaging in Gaseous Flows. PhD thesis, Stanford University Mechanical Engineering Department, 1999). The collisional constants of proportionality, which govern vibrational relaxation, are shown to be temperature dependent at elevated pressures. A new oxygen quenching rate is proposed which takes into account collisions with oxygen as well as the oxygen-assisted intersystem crossing component. Additionally, global trends in ketone photophysics are presented and discussed.

  2. Optimization and Control of Pressure Swing Adsorption Processes Under Uncertainty

    KAUST Repository

    Khajuria, Harish


    The real-time periodic performance of a pressure swing adsorption (PSA) system strongly depends on the choice of key decision variables and operational considerations such as processing steps and column pressure temporal profiles, making its design and operation a challenging task. This work presents a detailed optimization-based approach for simultaneously incorporating PSA design, operational, and control aspects under the effect of time variant and invariant disturbances. It is applied to a two-bed, six-step PSA system represented by a rigorous mathematical model, where the key optimization objective is to maximize the expected H2 recovery while achieving a closed loop product H2 purity of 99.99%, for separating 70% H2, 30% CH4 feed. The benefits over sequential design and control approach are shown in terms of closed-loop recovery improvement of more than 3%, while the incorporation of explicit/multiparametric model predictive controllers improves the closed loop performance. © 2012 American Institute of Chemical Engineers (AIChE).

  3. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

    Directory of Open Access Journals (Sweden)

    Peng Wang


    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  4. The Global Historical Climatology Network: Long-term monthly temperature, precipitation, sea level pressure, and station pressure data

    Energy Technology Data Exchange (ETDEWEB)

    Vose, R.S. [Tennessee Univ., Knoxville, TN (United States). Energy, Environment and Resources Center; Schmoyer, R.L. [Oak Ridge National Lab., TN (United States); Steurer, P.M.; Peterson, T.C.; Heim, R.; Karl, T.R. [National Climatic Data Center, Asheville, NC (United States); Eischeid, J.K. [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences


    Interest in global climate change has risen dramatically during the last several years. In a similar fashion, the number of data sets available to study global change has also increased. Unfortunately, these data sets have been compiled by many different organizations/researchers, making it confusing and time consuming for individual researchers to acquire the ``best`` data. In response to this rapid growth in the number of global data sets, the Carbon Dioxide Information Analysis Center (CDIAC) and the National Climatic Data Center (NCDC) commenced the Global Historical Climatology Network (GHCN) project. The purpose of this project is to compile an improved global base-line data set of long-term monthly mean temperature, precipitation, sea level pressure, and station pressure for a dense network. of worldwide meteorological stations. Specifically, the GHCN project seeks to consolidate the numerous preexisting national-, regional-, and global-scale data sets into a single global climate data base that can be updated, enhanced, and distributed at regular intervals. The first version of the GHCN data base was completed during the summer of 1992. It contains 6039 temperature, 7533 precipitation, 1883 sea level pressure, and 1873 station pressure stations. All stations have at least 10 years of data, 40% have more than 50 years of data, and 10% have more than 100 years of data. Spatial coverage is good over most of the globe, particularly for the United States and central Europe. In comparison to other major global data sets, dramatic improvements are evident over South America, Africa, and Asia. The GHCN data base is available as a Numeric Data Package (NDP) from CDIAC. The NDP consists of this document and two magnetic tapes that contain machine-readable data files and accompanying retrieval codes. This document describes, in detail, both the GHCN data base and the contents of the magnetic tap

  5. The Global Historical Climatology Network: Long-term monthly temperature, precipitation, sea level pressure, and station pressure data

    Energy Technology Data Exchange (ETDEWEB)

    Vose, R.S. (Tennessee Univ., Knoxville, TN (United States). Energy, Environment and Resources Center); Schmoyer, R.L. (Oak Ridge National Lab., TN (United States)); Steurer, P.M.; Peterson, T.C.; Heim, R.; Karl, T.R. (National Climatic Data Center, Asheville, NC (United States)); Eischeid, J.K. (Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences)


    Interest in global climate change has risen dramatically during the last several years. In a similar fashion, the number of data sets available to study global change has also increased. Unfortunately, these data sets have been compiled by many different organizations/researchers, making it confusing and time consuming for individual researchers to acquire the best'' data. In response to this rapid growth in the number of global data sets, the Carbon Dioxide Information Analysis Center (CDIAC) and the National Climatic Data Center (NCDC) commenced the Global Historical Climatology Network (GHCN) project. The purpose of this project is to compile an improved global base-line data set of long-term monthly mean temperature, precipitation, sea level pressure, and station pressure for a dense network. of worldwide meteorological stations. Specifically, the GHCN project seeks to consolidate the numerous preexisting national-, regional-, and global-scale data sets into a single global climate data base that can be updated, enhanced, and distributed at regular intervals. The first version of the GHCN data base was completed during the summer of 1992. It contains 6039 temperature, 7533 precipitation, 1883 sea level pressure, and 1873 station pressure stations. All stations have at least 10 years of data, 40% have more than 50 years of data, and 10% have more than 100 years of data. Spatial coverage is good over most of the globe, particularly for the United States and central Europe. In comparison to other major global data sets, dramatic improvements are evident over South America, Africa, and Asia. The GHCN data base is available as a Numeric Data Package (NDP) from CDIAC. The NDP consists of this document and two magnetic tapes that contain machine-readable data files and accompanying retrieval codes. This document describes, in detail, both the GHCN data base and the contents of the magnetic tap

  6. Pressure-concentration-temperature characterization of St909 getter alloy with hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ghezzi, F. [Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica del Plasma; Boffito, C. [SAES Getters S.p.A., Milan (Italy)


    One of the major issues related to the next generation of fusion reactors is tritium recovery and recycling from tritiated water. Among the various approaches proposed, chemical dissociation of tritiated water over active beds based on reactive alloys appears to be a promising solution. It enables, in fact, safe recovery of tritium by exploiting the relatively high equilibrium pressures, even at low concentrations and operating temperature, of selected alloys. This paper presents the results of pressure-temperature-composition measurements carried out on a Zr-Mn-Fe alloy, named St909, candidate for such an application. Equilibrium isotherms have been determined between room temperature and 400{sup o}C for low hydrogen concentrations, and at room temperature for higher concentrations, exploring the bi-phasic region. Sieverts` law appears to be obeyed in the low concentration range, at H/A ratios of less than 0.03. (Author).

  7. Record high magnetic ordering temperature in a lanthanide at extreme pressure (United States)

    Lim, J.; Fabbris, G.; Haskel, D.; Schilling, J. S.


    Today’s best permanent magnet materials, SmCo5 and Nd2Fe14B, could likely be made significantly more powerful were it not necessary to dilute the strong magnetism of the rare earth ions (Sm, Nd) with the 3d transition elements (Fe, Co). Since the rare-earth metals order magnetically at relatively low temperatures T o ≤ 292 K, transition elements must be added to bring T o to temperatures well above ambient. Under pressure T o (P) for the neighboring lanthanides Gd, Tb, and Dy follows a notably nonmonotonic, but nearly identical, dependence to ∼60 GPa. At higher pressures, however, Tb and Dy exhibit highly anomalous behavior, T o for Dy soaring to temperatures well above ambient. We suggest that this anomalously high magnetic ordering temperature is an heretofore unrecognized feature of the Kondo lattice state.

  8. ANSYS-based birefringence property analysis of side-hole fiber induced by pressure and temperature (United States)

    Zhou, Xinbang; Gong, Zhenfeng


    In this paper, we theoretically investigate the influences of pressure and temperature on the birefringence property of side-hole fibers with different shapes of holes using the finite element analysis method. A physical mechanism of the birefringence of the side-hole fiber is discussed with the presence of different external pressures and temperatures. The strain field distribution and birefringence values of circular-core, rectangular-core, and triangular-core side-hole fibers are presented. Our analysis shows the triangular-core side-hole fiber has low temperature sensitivity which weakens the cross sensitivity of temperature and strain. Additionally, an optimized structure design of the side-hole fiber is presented which can be used for the sensing application.

  9. Effects of gas temperature, pressure, and discharge power on nucleation time of nano-particles in low pressure C2H2/Ar RF plasmas (United States)

    Lin, Jiashu; Orazbayev, Sagi; Hénault, Marie; Lecas, Thomas; Takahashi, Kazuo; Boufendi, Laïfa


    The formation of dust particles in low-pressure plasmas is a 3-step process. The first one corresponds to nucleation and growth of nanoparticles by chain reactions between ions and gas molecules, the second one is agglomeration of the nanoparticles to form larger particles, and finally, the particles grow by radical deposition on their surfaces. In this work, the nucleation time for carbon dust particles was studied in low pressure acetylene/argon radio frequency (RF) plasmas. Since the self-bias voltage on a powered electrode was drastically affected by the transition from the nucleation to the agglomeration phases, the nucleation time was measured by observing the self-bias voltage time evolution. The nucleation time increases with the gas temperature and decreases when the gas pressure and the RF power are increased. A kinetic model, involving balance between diffusion and charging times of the nanoparticles as well as the chain reactions, is used to explain the exponential dependence of the nucleation time on the gas temperature. The balance between the times was especially indispensable to get good agreement between the model and the experimental results.

  10. Extreme temperature robust optical sensor designs and fault-tolerant signal processing (United States)

    Riza, Nabeel Agha [Oviedo, FL; Perez, Frank [Tujunga, CA


    Silicon Carbide (SiC) probe designs for extreme temperature and pressure sensing uses a single crystal SiC optical chip encased in a sintered SiC material probe. The SiC chip may be protected for high temperature only use or exposed for both temperature and pressure sensing. Hybrid signal processing techniques allow fault-tolerant extreme temperature sensing. Wavelength peak-to-peak (or null-to-null) collective spectrum spread measurement to detect wavelength peak/null shift measurement forms a coarse-fine temperature measurement using broadband spectrum monitoring. The SiC probe frontend acts as a stable emissivity Black-body radiator and monitoring the shift in radiation spectrum enables a pyrometer. This application combines all-SiC pyrometry with thick SiC etalon laser interferometry within a free-spectral range to form a coarse-fine temperature measurement sensor. RF notch filtering techniques improve the sensitivity of the temperature measurement where fine spectral shift or spectrum measurements are needed to deduce temperature.

  11. Oral bacterial inactivation using a novel low-temperature atmospheric-pressure plasma device

    Directory of Open Access Journals (Sweden)

    Ya-Ting Chang


    Conclusion: The novel low-temperature atmospheric-pressure device was capable of achieving effective sterilization of E. faecalis within a 2-minute interval. Further studies are needed to validate complete inactivation, refine the laboratory-made low-temperature plasma device, and develop a new plasma-jet device, which will be superior to traditional sterilization methods and can be used in root canal environment. This novel sterilization method can also be used as a clinical reference tool.

  12. Reusable pressure seal for low temperature use requiring a small annular space (United States)

    Clark, J. C.; Chilson, P. B.; Ihas, G. G.


    A reusable, low-temperature, super leaktight joint sealed with epoxy is presented which increases the available working area over that provided by a coventional bolted O-ring system. The seal is usable at arbitrarily low temperatures and was tested with a pressure of 70 bar with no apparent deterioration in performance. The simple method of assembly and disassembly is described and the results of various tests are discussed.

  13. Space Station Freedom pressurized element interior design process (United States)

    Hopson, George D.; Aaron, John; Grant, Richard L.


    The process used to develop the on-orbit working and living environment of the Space Station Freedom has some very unique constraints and conditions to satisfy. The goal is to provide maximum efficiency and utilization of the available space, in on-orbit, zero G conditions that establishes a comfortable, productive, and safe working environment for the crew. The Space Station Freedom on-orbit living and working space can be divided into support for three major functions: (1) operations, maintenance, and management of the station; (2) conduct of experiments, both directly in the laboratories and remotely for experiments outside the pressurized environment; and (3) crew related functions for food preparation, housekeeping, storage, personal hygiene, health maintenance, zero G environment conditioning, and individual privacy, and rest. The process used to implement these functions, the major requirements driving the design, unique considerations and constraints that influence the design, and summaries of the analysis performed to establish the current configurations are described. Sketches and pictures showing the layout and internal arrangement of the Nodes, U.S. Laboratory and Habitation modules identify the current design relationships of the common and unique station housekeeping subsystems. The crew facilities, work stations, food preparation and eating areas (galley and wardroom), and exercise/health maintenance configurations, waste management and personal hygiene area configuration are shown. U.S. Laboratory experiment facilities and maintenance work areas planned to support the wide variety and mixtures of life science and materials processing payloads are described.

  14. Survey of industrial coal conversion equipment capabilities: high-temperature, high-pressure gas purification

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, J. P.; Edwards, M. S.


    In order to ensure optimum operating efficiencies for combined-cycle electric generating systems, it is necessary to provide gas treatment equipment capable of operating at high temperatures (>1000/sup 0/F) and high pressure (>10 atmospheres absolute). This equipment, when assembled in a process train, will be required to condition the inlet stream to a gas turbine to suitable levels of gas purity (removal of particulate matter, sulfur, nitrogen, and alkali metal compounds) so that it will be compatible with both environmental and machine constraints. In this work, a survey of the available and developmental equipment for the removal of particulate matter and sulfur compounds has been conducted. In addition, an analysis has been performed to evaluate the performance of a number of alternative process configurations in light of overall system needs. Results from this study indicate that commercially available, reliable, and economically competitive hot-gas cleanup equipment capable of conditioning raw product gas to the levels required for high-temperatue turbine operation will not be available for some time.

  15. Critical Assessment of Temperature Distribution in Submerged Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Vineet Negi


    Full Text Available Temperature distribution during any welding process holds the key for understanding and predicting several important welding attributes like heat affected zone, microstructure of the weld, residual stress, and distortion during welding. The accuracy of the analytical approaches for modeling temperature distribution during welding has been constrained by oversimplified assumptions regarding boundary conditions and material properties. In this paper, an attempt has been made to model the temperature distribution during submerged arc welding process using finite element modeling technique implemented in ANSYS v12. In the present analysis, heat source is assumed to be double-ellipsoidal with Gaussian volumetric heat generation. Furthermore, variation of material properties with temperature and both convective and radiant heat loss boundary condition have been considered. The predicted temperature distribution is then validated against the experimental results obtained by thermal imaging of the welded plate, and they are found to be in a good agreement.

  16. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control. (United States)


    ... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

  17. Effects of temperature and pressure on the performance of a solid oxide fuel cell running on steam reformate of kerosene

    Energy Technology Data Exchange (ETDEWEB)

    Chick, Lawrence A.; Marina, Olga A.; Coyle, Christopher A.; Thomsen, Edwin C.


    A button solid oxide fuel cell with a La0.6Sr0.4Co0.2Fe0.8O3 cathode and a nickel-YSZ anode was tested over a range of temperatures from 650 to 800°C and a range of pressures from 101 to 724 kPa. The fuel was simulated steam-reformed kerosene and the oxidant was air. The observed increases in open circuit voltages (OCV) were accurately predicted by the Nernst equation. Kinetics also increased, although the power boost due to kinetics was about two thirds as large as the boost due to OCV. The total power boost in going from 101 to 724 kPa at 750°C and 0.8 volts was 66%. Impedance spectroscopy demonstrated a significant decrease in electrodic losses at elevated pressures. Complex impedance spectra were dominated by a combination of low frequency processes that decreased markedly with increasing pressure. A composite of high-frequency processes also decreased with pressure, but to a lesser extent. An empirical algorithm that accurately predicts the increased fuel cell performance at elevated pressures was developed for our results and was also suitable for some, but not all, data reported in the literature.

  18. The predictable influence of soil temperature and barometric pressure changes on vapor intrusion (United States)

    Barnes, David L.; McRae, Mary F.


    Intrusion of volatile organic compounds in the gas phase has impacted many buildings in many different locations. Various building and environmental factors such as buoyancy of heated air and changes in barometric pressure can influence indoor air concentrations due to vapor intrusion in these buildings resulting in seasonal and daily variability. One environmental factor that previous research has not adequately addressed is soil temperature. In this study we present two northern region study sites where the seasonal trends in indoor air VOC concentrations positively correlate with soil temperature, and short-term (days) variations are associated with barometric pressure changes. We present simple and multivariate linear relationships of indoor air concentrations as a function of soil temperature and barometric pressure. Results from this study show that small changes in soil temperature can result in relatively large changes in indoor air VOC concentrations where the gas phase VOCs are sourced from non-aqueous phase liquids contained in the soil. We use the results from this study to show that a five degree Celsius increase in soil temperature, a variation in soil temperature that is possible in many climatic regions, results in a two-fold increase in indoor air VOC concentrations. Additionally, analysis provides insight into how building ventilation, diffusion, and the relative rate of soil-gas flow across the slab both from the subsurface into the building and from the building into the subsurface impact short term variations in concentrations. With these results we are able to provide monitoring recommendations for practitioners.

  19. ``Multi-temperature'' method for high-pressure sorption measurements on moist shales (United States)

    Gasparik, Matus; Ghanizadeh, Amin; Gensterblum, Yves; Krooss, Bernhard M.


    A simple and effective experimental approach has been developed and tested to study the temperature dependence of high-pressure methane sorption in moist organic-rich shales. This method, denoted as "multi-temperature" (short "multi-T") method, enables measuring multiple isotherms at varying temperatures in a single run. The measurement of individual sorption isotherms at different temperatures takes place in a closed system ensuring that the moisture content remains constant. The multi-T method was successfully tested for methane sorption on an organic-rich shale sample. Excess sorption isotherms for methane were measured at pressures of up to 25 MPa and at temperatures of 318.1 K, 338.1 K, and 348.1 K on dry and moisture-equilibrated samples. The measured isotherms were parameterized with a 3-parameter Langmuir-based excess sorption function, from which thermodynamic sorption parameters (enthalpy and entropy of adsorption) were obtained. Using these, we show that by taking explicitly into account water vapor as molecular species in the gas phase with temperature-dependent water vapor pressure during the experiment, more meaningful results are obtained with respect to thermodynamical considerations. The proposed method can be applied to any adsorbent system (coals, shales, industrial adsorbents) and any supercritical gas (e.g., CH4, CO2) and is particularly suitable for sorption measurements using the manometric (volumetric) method.

  20. Removal of dust from flue gas at elevated temperatures and pressures. Roeggasrensning for stoev ved hoej temperatur og hoejt tryk

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, D.V.; Rasmussen, J.


    Several new coal-based power generation systems are now ready for commercial application. Especially Integrated coal Gasification with combined Cycle (IGCC) and pressurized Fluidized Bed Combustion possess the potential for reducing emissions of SOx, NOx and particulates compared to conventional technology. In addition to this a decrease in heat-rate is possible. However, the decrease in heat-rate is dependant on the temperature of which the removal of particulated and gaseous pollutants takes place. Using state-of-the-art technology this temperature is 25-40 deg. C, but the efficiency improvement will only be substantial if the temperature can be raised to 400-500 deg. C or more. The coal gasification, which is the heart of an IGCC-system, can be caried out in a number of ways. Since the hot gas clean-up equipment (HGCU) to some extent is dependant on the gasification technology used, a description of the leading coal gasification systems is given. It is concluded that special interest should be given to gasifiers of the entrained flow type. The aim is to develope a HGCU-system for the removal of gaseous pollutants as well as particulate matter. The operating principles and stage of development of the competing technologies for dust removal at high temperature and pressure are described. Special attention is paid to the electrostatic precipitator, and possible solutions to problems related ot this technology are given. (AB) 165 refs.

  1. Temperature and high pressure effects on the structural features of catalytic nanocomposites oxides by Raman spectroscopy. (United States)

    da Silva, Antonio N; Pinto, Raffael C F; Freire, Paulo T C; Junior, Jose Alves L; Oliveira, Alcineia C; Filho, Josué M


    Structural characterizations of nanostructured oxides were studied by X-ray diffraction (XRD), Raman and infrared spectroscopy. The oxides catalysts namely, SnO2, ZrO2, CeO2, MnOx, Al2O3 and TiO2 were prepared by a nanocasting route and the effect of the temperature and pressure on the stability of the solids was evaluated. Raman spectra showed that ZrO2 and TiO2 exhibited phase transitions at moderate temperatures whereas CeO2, SnO2 and MnOx had an effective creation of defects in their structures upon annealing at elevated temperatures. The results suggested also that the effect of the temperature on the particles growth is related to the type of oxide. In this regard, phase transition by up to 600°C accelerated the sintering of ZrO2 and CeO2 grains compared to TiO2, SnO2 and MnOx counterparts. Under hydrostatic pressures lower than 10GPa, rutile TiO2 and tetragonal ZrO2 exhibited pressure induced phase transition whereas CeO2 and SnO2 were stable at pressures close to 15GPa. The experiments revealed that the nanostructured SnO2 oxide exhibited stable performance at relatively high temperatures without phase transition or sintering, being suitable to be used as catalysts in the range of temperature and pressure studied. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 46 CFR 154.650 - Cargo tank and process pressure vessel welding. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank and process pressure vessel welding. 154.650... Equipment Construction § 154.650 Cargo tank and process pressure vessel welding. (a) Cargo tank and process pressure vessel welding must meet Subpart 54.05 and Part 57 of this chapter. (b) Welding consumables used...

  3. Phase Interrogation Used for a Wireless Passive Pressure Sensor in an 800 °C High-Temperature Environment

    Directory of Open Access Journals (Sweden)

    Huixin Zhang


    Full Text Available A wireless passive pressure measurement system for an 800 °C high-temperature environment is proposed and the impedance variation caused by the mutual coupling between a read antenna and a LC resonant sensor is analyzed. The system consists of a ceramic-based LC resonant sensor, a readout device for impedance phase interrogation, heat insulating material, and a composite temperature-pressure test platform. Performances of the pressure sensor are measured by the measurement system sufficiently, including pressure sensitivity at room temperature, zero drift from room temperature to 800 °C, and the pressure sensitivity under the 800 °C high temperature environment. The results show that the linearity of sensor is 0.93%, the repeatability is 6.6%, the hysteretic error is 1.67%, and the sensor sensitivity is 374 KHz/bar. The proposed measurement system, with high engineering value, demonstrates good pressure sensing performance in a high temperature environment.

  4. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials. (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; Di, Chong-an; Zhu, Daoben


    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  5. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; di, Chong-An; Zhu, Daoben


    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  6. Picosecond ballistic imaging of diesel injection in high-temperature and high-pressure air (United States)

    Duran, Sean P.; Porter, Jason M.; Parker, Terence E.


    The first successful demonstration of picosecond ballistic imaging using a 15-ps-pulse-duration laser in diesel sprays at temperature and pressure is reported. This technique uses an optical Kerr effect shutter constructed from a CS2 liquid cell and a 15-ps pulse at 532 nm. The optical shutter can be adjusted to produce effective imaging pulses between 7 and 16 ps. This technique is used to image the near-orifice region (first 3 mm) of diesel sprays from a high-pressure single-hole fuel injector. Ballistic imaging of dodecane and methyl oleate sprays injected into ambient air and diesel injection at preignition engine-like conditions are reported. Dodecane was injected into air heated to 600 °C and pressurized to 20 atm. The resulting images of the near-orifice region at these conditions reveal dramatic shedding of the liquid near the nozzle, an effect that has been predicted, but to our knowledge never before imaged. These shedding structures have an approximate spatial frequency of 10 mm-1 with lengths from 50 to 200 μm. Several parameters are explored including injection pressure, liquid fuel temperature, air temperature and pressure, and fuel type. Resulting trends are summarized with accompanying images.

  7. Thermodynamic properties of standard seawater: extensions to high temperatures and pressures

    Directory of Open Access Journals (Sweden)

    J. Safarov


    Full Text Available Measurements of (p, ρ, T properties of standard seawater with practical salinity S≈35, temperature T=(273.14 to 468.06 K and pressures, p, up to 140 MPa are reported with the reproducibility of the density measurements observed to be in the average percent deviation range Δρ/ρ=±(0.01 to 0.03%. The measurements are made with a newly constructed vibration-tube densimeter which is calibrated using double-distilled water, methanol and aqueous NaCl solutions. Based on these and previous measurements, an empirical expression for the density of standard seawater has been developed as a function of pressure and temperature. This equation is used to calculate other volumetric properties including isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, the thermal pressure coefficient, internal pressure and the secant bulk modulus. The results can be used to extend the present equation of state of seawater to higher temperatures for pressure up to 140 MPa.

  8. Thermal Insulation Performance of Textile Structures for Spacesuit Applications at Martian Pressure and Temperature (United States)

    Orndoff, Evelyne; Trevino, Luis A.


    Protection of astronauts from the extreme temperatures in the space environment has been provided in the past using multi-layer insulation in ultra-high vacuum environments of low earth orbit and the lunar surface. For planetary environments with residual gas atmospheres such as Mars with ambient pressures between 8 to 14 hPa (8 to 14 mbar), new protection techniques are required because of the dominating effect of the ambient gas on heat loss through the insulation. At Mars ambient pressure levels, the heat loss can be excessive at expected suit external temperatures of 172 K with state-of-the-art suit insulation, requiring an active heat source and its accompanying weight and volume penalties. Micro-fibers have been identified as one potential structure to reduce the heat losses, but existing fundamental data on fiber heat transfer at low pressure is lacking for integrated fabric structures. This baseline study presents insulation performance test data at different pressures and fabric loads for selected polyesters and aramids as a function of fiber density, fiber diameter, fabric density, and fabric construction. A set of trend data of thermal conductivity versus ambient pressure is presented for each fiber and fabric construction design to identify the design effects on thermal conductivity at various ambient pressures, and to select a fiber and fabric design for further development as a suit insulation. The trend data also shows the pressure level at which thermal conductivity approaches a minimum, below which no further improvement is possible for a given fiber and fabric design. The pressure levels and resulting thermal conductivities from the trend data can then be compared to the ambient pressure at a planetary surface, Mars for example, to determine if a particular fiber and fabric design has potential as a suit insulation.

  9. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes. (United States)

    Nelson, Jacob A; Bugbee, Bruce


    The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  10. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

    Directory of Open Access Journals (Sweden)

    Jacob A Nelson

    Full Text Available The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  11. Investigation of temperature- and pressure effects on drilling fluid properties and related downhole torque and drag calculations


    Tveiterå, Martin


    Master's thesis in Petroleum engineering Increasing temperature and pressure with depth, affects the properties of drilling fluid. The effect of temperature and pressure on the density and viscosity of drilling fluid is of great importance. This is because, among several reasons, it affects the calculation of downhole pressure and the buoyancy factor for the well. Correct pressure estimation, could pose a great concern regarding well integrity. The buoyancy factor would affect the effectiv...

  12. Effects of temperature and CO2 pressure on the emission of N,N ...

    Indian Academy of Sciences (India)

    Effects of temperature and CO2 pressure on the emission of. N,N -dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important? KIZHMURI P DIVYAa,b, MICHAEL J BERTOCCHIa and RICHARD G WEISSa,∗. aDepartment of Chemistry, Georgetown University, Washington ...

  13. 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.

  14. Correlation between the season, temperature and atmospheric pressure with incidence and pathogenesis of acute appendicitis

    Directory of Open Access Journals (Sweden)

    Karanikolić Aleksandar


    Full Text Available Introduction. There is very little literature data on the correlation between the seasons, temperature and atmospheric pressure, and pathogenesis of acute appendicitis (AA. Objective. The aim of this research is to investigate the association between the seasons, changes in atmospheric temperature and pressure, and patients’ age and severity of the clinical form of AA in the city of Niš. Methods. This study included 395 patients diagnosed with AA, who, during the two-year period, from July 1st 2011 to June 30th 2013, were hospitalized and operated on at the Department of General Surgery, Clinical Center in Niš, Serbia. Results. The increased average daily values of barometric pressure by 1 millibar on the day when the event took place was associated (p < 0.05 with the decrease of total risk of the occurrence of appendicitis by 2.2% (0.2-4.1%. In all observed patients, each increase of the mean daily temperature by 1°C three days before the event took place (Lag 3 was associated (p < 0.05 with the increase of total risk of the occurrence of appendicitis by 1.3% (0.1-2.5%. Conclusion. According to the results of this research, we can conclude that patients’ sex, age and severity of the clinical form of AA are not in connection with the seasons, while there are certain connections between appendicitis occurrence and atmospheric temperature and pressure.

  15. On the pressure velocity and temperature factors and the effect of ...

    African Journals Online (AJOL)

    In this paper, we examine the effects of viscosity on the blood pressure, velocity and temperature distributions in the arterial blood flow in the absence of outflows. The governing continuity, momentum and energy equations are solved analytically by method of characteristics. Using the wavefront expansions, an equation of ...

  16. HoB4 at high pressure and low temperature: an experimental and theoretical study

    DEFF Research Database (Denmark)

    Olsen, J. Staun; Waśkowska, A.; Gerward, Leif


    Single crystals of HoB4 have been grown and used for synchrotron X-ray diffraction studies at pressures up to 23GPa and temperatures down to 100K. The experimental bulk modulus 195 ± 6GPa is in good agreement with 188.4 and 198.2GPa values calculated in the LSDA and LSDA+U approximations, indicat...

  17. Effects of elevated CO2 partial pressure and temperature on the coccolithophore Syracosphaera pulchra

    NARCIS (Netherlands)

    Fiorini, S.; Middelburg, J.J.; Gattuso, J.P.


    The effects of elevated partial pressure of CO2 (pCO2) and temperature on the cocco - lithophore Syracosphaera pulchra were investigated in isolation and in combination. Both the diploid and the haploid life stages were studied. Batch cultures were grown under 4 conditions: 400 μatm and 19°C; 400

  18. On the Pressure and Temperature Dependence of the Absorption Coefficient of NH3

    Directory of Open Access Journals (Sweden)

    F. Aousgi


    Full Text Available The effects of pressure and temperature on the absorption coefficient of ammonia (NH3 gas self-perturbed and perturbed by nitrogen (N2 gas have been measured. We varied the gas pressure from 10 to 160 Torr and the temperature from 235 to 296 K in order to study the absorption coefficient at the center and the wings of lines in the ν4 band of NH3. These measurements were made using a high resolution (0.0038 cm-1 Bruker Fourier-transform spectrometer. These spectra have been analyzed using the method of multipressure technique permitting to succeed to an evolution of the absorption coefficient with the pressure and the quantum numbers J and K of the NH3 molecule. The results show that the absorption coefficient varies as a quadratic function of the pressure at the center of a given line. However, it has a linear evolution in the wings of the line. Moreover, the absorption coefficients are inversely proportional to temperature in the wings when NH3 lines are broadened by N2. The retrieved values of these coefficients were used to derive the temperature dependence of N2 broadening NH3 lines. The absorption coefficients were shown to fit closely the well-known exponential law.

  19. Nuclear ordering in lithium and an upper limit on its ambient pressure superconducting transition temperature. (United States)

    Juntunen, K I; Tuoriniemi, J T


    We have discovered spontaneous ordering of nuclear spins in lithium metal by NMR measurements at very low temperatures. In low magnetic fields, Blithium at normal pressure down to T(e) approximately 100 microK (B<10 nT).

  20. Thermal equation of state of synthetic orthoferrosilite at lunar pressures and temperatures

    NARCIS (Netherlands)

    de Vries, J.; Jacobs, J.M.G.; van den Berg, A.P.; Wehber, M.; Lathe, C.; McCammon, C.A.; van Westrenen, W.


    Iron-rich orthopyroxene plays an important role in models of the thermal and magmatic evolution of the Moon, but its density at high pressure and high temperature is not well-constrained. We present in situ measurements of the unit-cell volume of a synthetic polycrystalline end-member

  1. Pressure-Driven Commensurate-Incommensurate Transition Low-Temperature Submonolayer Krypton on Graphite

    DEFF Research Database (Denmark)

    Nielsen, Mourits; Als-Nielsen, Jens Aage; Bohr, Jakob


    By using D2 gas as a source of two-dimensional spreading pressure, we have studied the commensurate-incommensurate (C-I) transition in submonolayer Kr on ZYX graphite at temperatures near 40 K. High-resolution synchrotron x-ray diffraction results show both hysteresis and C-I phase coexistence, c...

  2. 40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors. (United States)


    ... sensors, and dewpoint sensors. 1065.215 Section 1065.215 Protection of Environment ENVIRONMENTAL... Measurement of Engine Parameters and Ambient Conditions § 1065.215 Pressure transducers, temperature sensors, and dewpoint sensors. (a) Application. Use instruments as specified in this section to measure...

  3. Alkaline electrolysis cell at high temperature and pressure of 250 °C and 42 bar

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg


    A new type of alkaline electrolysis cells with nickel foam based gas diffusion electrodes and KOH (aq) immobilized in mesoporous SrTiO3 has been developed and tested at temperatures and pressures up to 250 °C and 42 bar, respectively. Current densities of 1.0 A cm−2 have been measured at a cell...

  4. Temperature stratification and insect pest populations in stored wheat with suction versus pressure aeration (United States)

    A three-year study was conducted to compare temperature profiles in the headspace and in the bulk mass of wheat aerated through pressure aeration and suction aeration. Insect pitfall traps were used to measure naturally-occurring populations of stored product insects. Results show uniform distributi...

  5. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures

    NARCIS (Netherlands)

    Gu, Z.; Witschas, B.; van der Water, W.; Ubachs, W.M.G.


    Rayleigh-Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The

  6. High-pressure high-temperature equation of state of graphite from Monte Carlo simulations

    NARCIS (Netherlands)

    Colonna, F.; Fasolino, A.; Meijer, E.J.


    The thermoelastic behavior of graphite is experimentally accessible in a limited range of pressures and temperatures. Here we perform Monte Carlo simulations based on the accurate long range carbon bond-order potential (LCBOPII) in order to study graphite in a wider range of thermodynamic

  7. Standard guide for corrosion tests in high temperature or high pressure environment, or both

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This guide covers procedures, specimens, and equipment for conducting laboratory corrosion tests on metallic materials under conditions of high pressure (HP) or the combination of high temperature and high pressure (HTHP). See for definitions of high pressure and temperature. 1.2 Tests conducted under HP or HTHP by their nature have special requirements. This guide establishes the basic considerations that are necessary when these conditions must be incorporated into laboratory corrosion tests. 1.3 The procedures and methods in this guide are applicable for conducting mass loss corrosion, localized corrosion, and electrochemical tests as well as for use in environmentally induced cracking tests that need to be conducted under HP or HTHP conditions. 1.4 The primary purpose for this guide is to promote consistency of corrosion test results. Furthermore, this guide will aid in the comparison of corrosion data between laboratories or testing organizations that utilize different equipment. 1.5 The values s...

  8. Raman and IR studies of polymorphism in n-hexanol at high pressure and low temperature (United States)

    Ren, Yufen; Cheng, Xuerui; Zhu, Xiang; Yang, Kun; Wang, Yongqiang; Yuan, Chaosheng


    As one important organic molecule, the structure stability and polymorphism of n-hexanol (C6H14O) have been investigated at low temperature and high pressure using in situ Raman and infrared spectroscopy. The existence of three polymorphs is observed for n-hexanol in this work. The liquid n-hexanol converts to the monoclinic γ-phase structure at 203 K and 0.8 GPa respectively. Additional changes are observed in spectra at 3.0 and 7.3 GPa, because of two additional phase transitions to monoclinic β-phase structures. In addition, conformational change between trans and gauche is also observed accompanied by the phase transitions. Moreover, hydrogen-bond formation and its response to the external pressure are confirmed from infrared spectra. Finally, the phase transitions under high pressure and low temperature are reversible. These results are helpful for understanding of structure transition under external condition for n-alcohols and other organic molecules.

  9. The Role of Temperature in Shear Instability and Bifurcation of Internally Pressurized Deep Boreholes (United States)

    Hu, Manman; Veveakis, Manolis; Poulet, Thomas; Regenauer-Lieb, Klaus


    This paper investigates localized shear deformation around a borehole due to internal pressure in the well such as by fluid injection. Using an elasto-visco-plastic formulation combined with damage mechanics for the effect of shear cracking, we first benchmark the model against analytical solutions and then provide bifurcation criteria for the onset of localized cracking at different temperature conditions. We report that at increased temperatures of the rock formation, hot fluid injection promotes shear stimulation, while cold fluid suppresses it. This counter-intuitive result can offer new pathways of effective stimulation in high-temperature environments, like those encountered in enhanced geothermal systems.

  10. Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment (United States)

    Liaw, P. K.; Logsdon, W. A.; Begley, J. A.


    The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure vessel steels and submerged arc weldments were generally conservative, compared with the approrpriate American Society of Mechanical Engineers (ASME) Section XI water environmental reference curve. The growth rate of fatigue cracks in the base materials, however, was considerably faster in the HPW environment than in a corresponding 288°C (550°F) base line air environment. The growth rate of fatigue cracks in the two submerged are weldments was also accelerated in the HPW environment but to a significantly lesser degree than that demonstrated by the corresponding base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials, as compared with the weldments, was attributed to a different sulfide composition and morphology.

  11. Evidence of a pressure-induced metallization process in monoclinic VO2. (United States)

    Arcangeletti, E; Baldassarre, L; Di Castro, D; Lupi, S; Malavasi, L; Marini, C; Perucchi, A; Postorino, P


    Raman and combined infrared transmission and reflectivity measurements were carried out at room temperature (RT) on monoclinic VO2 over the 0-19 GPa and 0-14 GPa pressure ranges. Both lattice dynamics and optical gap show a remarkable stability up to P* approximately 10 GPa whereas subtle modifications of V ion arrangements within the monoclinic lattice, together with the onset of a metallization process via band gap filling, are observed for P >P*. Differently from P=0, where the VO2 metallic phase is found only in conjunction with the rutile structure above 340 K, a new RT metallic phase within a monoclinic structure appears accessible in the high pressure regime.

  12. Thermal diffusivity of Swedish meatballs, pork meat pate and tomato puree during high pressure processing (United States)

    Landfeld, Ales; Strohalm, Jan; Stancl, Jaromir; Houska, Milan


    Our study is directed at the effects of high pressure on the thermal diffusivity of selected food samples - a fresh meat formulation for Swedish meatballs, pork meat pate and tomato puree. Preheated food samples were placed in a copper cell and tested at nominal pressures of 400 and 500 MPa in a high pressure chamber. The thermal diffusivity was estimated from the recorded time course of temperatures (at the center of the food sample, at the wall of the copper cell, and 7.5 mm from the wall) during the high pressure holding time. Measured time-temperature profiles were compared with predictions using the finite-element model to solve the problem of uneven heat conduction in an infinite, solid, linear cylinder using the linear temperature dependence of apparent thermal conductivity. Optimal parameters of the linear temperature dependence of apparent thermal conductivity were evaluated by comparing measured temperatures and temperatures calculated from the model. To minimize differences between measured and calculated temperatures, at the center of the sample, the Marquardt-Levenberg optimization method was used. The thermal diffusivity values of all food samples were linearly correlated with temperature for two levels of pressure. Thermal diffusivity values increased with increased pressure and temperature. † This paper was presented at the XLVIIIth European High Pressure Research Group (EHPRG 48) Meeting at Uppsala (Sweden), 25-29 July 2010.

  13. Application and possible benefits of high hydrostatic pressure or high-pressure homogenization on beer processing: A review. (United States)

    Santos, Lígia Mr; Oliveira, Fabiano A; Ferreira, Elisa Hr; Rosenthal, Amauri


    Beer is the most consumed beverage in the world, especially in countries such as USA, China and Brazil.It is an alcoholic beverage made from malted cereals, and the barley malt is the main ingredient, added with water, hops and yeast. High-pressure processing is a non-traditional method to preserve food and beverages. This technology has become more interesting compared to heat pasteurization, due to the minimal changes it brings to the original nutritional and sensory characteristics of the product, and it comprises two processes: high hydrostatic pressure, which is the most industrially used process, and high-pressure homogenization. The use of high pressure almost does not affect the molecules that are responsible for the aroma and taste, pigments and vitamins compared to the conventional thermal processes. Thus, the products processed by high-pressure processing have similar characteristics compared to fresh products, including beer. The aim of this paper was to review what has been investigated about beer processing using this technology regarding the effects on physicochemical, microbiology and sensory characteristics and related issues. It is organized by processing steps, since high pressure can be applied to malting, mashing, boiling, filtration and pasteurization. Therefore, the beer processed with high-pressure processing may have an extended shelf-life because this process can inactivate beer spoilage microorganisms and result in a superior sensory quality related to freshness and preservation of flavors as it does to juices that are already commercialized. However, beyond this application, high-pressure processing can modify protein structures, such as enzymes that are present in the malt, like α- and β-amylases. This process can activate enzymes to promote, for example, saccharification, or instead inactivate at the end of mashing, depending on the pressure the product is submitted, besides being capable of isomerizing hops to raise beer bitterness

  14. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste-Gómez


    Full Text Available An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa and temperature (2 °C to 90 °C. The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing. More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception.

  15. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature. (United States)

    Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar


    An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception.

  16. High-sensitivity Cryogenic Temperature Sensors using Pressurized Fiber Bragg Gratings (United States)

    Wu, Meng-Chou; DeHaven, Stanton L.


    Cryogenic temperature sensing was studied using a pressurized fiber Bragg grating (PFBG). The PFBG was obtained by simply applying a small diametric load to a regular fiber Bragg grating (FBG), which was coated with polyimide of a thickness of 11 micrometers. The Bragg wavelength of the PFBG was measured at temperatures from 295 to 4.2 K. A pressure-induced transition occurred at 200 K during the cooling cycle. As a result the temperature sensitivity of the PFBG was found to be nonlinear but reach 24 pm/K below 200 K, more than three times the regular FBG. For the temperature change from 80 K to 10 K, the PFBG has a total Bragg wavelength shift of about 470 pm, 10 times more than the regular FBG. From room temperature to liquid helium temperature the PFBG gives a total wavelength shift of 3.78 nm, compared to the FBG of 1.51 nm. The effect of the coating thickness on the temperature sensitivity of the gratings is also discussed.

  17. High Temperature Capacitive Pressure Sensor Employing a SiC Based Ring Oscillator (United States)

    Meredith, Roger D.; Neudeck, Philip G.; Ponchak, George E.; Beheim, Glenn M.; Scardelletti, Maximilian; Jordan, Jennifer L.; Chen, Liang-Yu; Spry, David J.; Krawowski, Michael J.; Hunter, Gary W.


    In an effort to develop harsh environment electronic and sensor technologies for aircraft engine safety and monitoring, we have used capacitive-based pressure sensors to shift the frequency of a SiC-electronics-based oscillator to produce a pressure-indicating signal that can be readily transmitted, e.g. wirelessly, to a receiver located in a more benign environment. Our efforts target 500 C, a temperature well above normal operating conditions of commercial circuits but within areas of interest in aerospace engines, deep mining applications and for future missions to the Venus atmosphere. This paper reports for the first time a ring oscillator circuit integrated with a capacitive pressure sensor, both operating at 500 C. This demonstration represents a significant step towards a wireless pressure sensor that can operate at 500 C and confirms the viability of 500 C electronic sensor systems.

  18. Probabilistic Structural Integrity Analysis of Boiling Water Reactor Pressure Vessel under Low Temperature Overpressure Event

    Directory of Open Access Journals (Sweden)

    Hsoung-Wei Chou


    Full Text Available The probabilistic structural integrity of a Taiwan domestic boiling water reactor pressure vessel has been evaluated by the probabilistic fracture mechanics analysis. First, the analysis model was built for the beltline region of the reactor pressure vessel considering the plant specific data. Meanwhile, the flaw models which comprehensively simulate all kinds of preexisting flaws along the vessel wall were employed here. The low temperature overpressure transient which has been concluded to be the severest accident for a boiling water reactor pressure vessel was considered as the loading condition. It is indicated that the fracture mostly happens near the fusion-line area of axial welds but with negligible failure risk. The calculated results indicate that the domestic reactor pressure vessel has sufficient structural integrity until doubling of the present end-of-license operation.

  19. Structural stability and phase transition of Bi 2 Te 3 under high pressure and low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. L.; Zhang, S. J.; Zhu, J. L.; Liu, Q. Q.; Wang, X. C.; Jin, C. Q.; Yu, J. C.


    Structural stability and phase transition of topological insulator Bi2Te3 were studied via angle-dispersive synchrotron radiation X-ray diffraction under high pressure and low temperature condition. The results manifest that the R-3m phase (phase I) is stable at 8 K over the pressure range up to 10 GPa and phase transition occurs between 8 K and 45 K at 8 GPa. According to the Birch-Murnaghan equation of state, the bulk modulus at ambient pressure B0 was estimated to be 45 ± 3 GPa with the assumption of B0' = 4. The structural robustness of phase I at 8 K suggests that the superconductivity below 10 GPa is related to phase I. Topological properties of superconducting Bi2Te3 phase under pressure were discussed.

  20. Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

    Directory of Open Access Journals (Sweden)



    Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

  1. Establishing a comprehensive networkwide pressure ulcer identification process. (United States)

    Vose, Courtney; Murphy, Robert X; Burmeister, David B; Buckenmyer, Charlotte; Davidson, Carolyn L; Meltsch, Tami J; Holko, Ginger; Karoly, Elizabeth; Porter, Bernadette Glenn


    Pressure ulcers (PUs) are a critical concern, endangering patients and requiring significant resources for treatment in Stage II/IV. The Centers for Medicare & Medicaid Services (CMS) denies reimbursement in cases where a more complex diagnosis-related group (DRG) is assigned as a result of hospital-acquired conditions such as a PU that could have been reasonably prevented. An interdisciplinary PU present-on-admission (POA) team developed an algorithm to support the early identification of PUs for units participating in the process. This approach standardized work, resulting in consistent (1) skin assessment, (2) physician notification, (3) reporting of findings in the patient safety reporting system, and (4) communication to receiving units. Computer-entry tools were developed and completed for six months by the patient care services unit-based process improvement councils; these councils made possible immediate "loop closure" for either positive feedback or needed reeducation with the nursing staff. The total number of PUs recognized and reported after implementation of the process improvement initiative--from April 1, 2008, to March 31, 2009--increased to 1,103--an increase of 36.3% in PU reporting when compared with the same period the year before. This initiative has yielded 100% effectiveness in identifying Stage III/IV PUs POA and in preventing hospital-acquired Stage III/IV PUs. The success of the project has helped to ensure high-quality patient care and protection of precious fiscal resources. The data suggest that the identification of all PUs that are present at time of admission is clinically feasible.

  2. Solubility of crude oil in methane as a function of pressure and temperature (United States)

    Price, L.C.; Wenger, L.M.; Ging, T.; Blount, C.W.


    The solubility of a 44?? API (0.806 sp. gr.) whole crude oil has been measured in methane with water present at temperatures of 50 to 250??C and pressures of 740 to 14,852 psi, as have the solubilities of two high molecular weight petroleum distillation fractions at temperatures of 50 to 250??C and pressures of 4482 to 25,266 psi. Both increases in pressure and temperature increase the solubility of crude oil and petroleum distillation fractions in methane, the effect of pressure being greater than that of temperature. Unexpectedly high solubility levels (0.5-1.5 grams of oil per liter of methane-at laboratory temperature and pressure) were measured at moderate conditions (50-200??C and 5076-14504 psi). Similar results were found for the petroleum distillation fractions, one of which was the highest molecular weight material of petroleum (material boiling above 266??C at 6 microns pressure). Unexpectedly mild conditions (100??C and 15,200 psi; 200??C and 7513 psi) resulted in cosolubility of crude oil and methane. Under these conditions, samples of the gas-rich phase gave solubility values of 4 to 5 g/l, or greater. Qualitative analyses of the crude-oil solute samples showed that at low pressure and temperature equilibration conditions, the solute condensate would be enriched in C5-C15 range hydrocarbons and in saturated hydrocarbons in the C15+ fraction. With increases in temperature and especially pressure, these tendencies were reversed, and the solute condensate became identical to the starting crude oil. The data of this study, compared to that of previous studies, shows that methane, with water present, has a much greater carrying capacity for crude oil than in dry systems. The presence of water also drastically lowers the temperature and pressure conditions required for cosolubility. The data of this and/or previous studies demonstrate that the addition of carbon dioxide, ethane, propane, or butane to methane also has a strong positive effect on crude oil

  3. Processing of pharmaceutical materials by electrospraying under reduced pressure. (United States)

    Nyström, Maija; Murtomaa, Matti; Roine, Jorma; Sandler, Niklas; Salonen, Jarno


    Electrospraying was used in drug particle production. The aim of the research was to evaluate the possibilities to produce drug particles with desired pharmaceutical properties by electrospraying. In particular, the effect of drying pressure on particle properties was studied. A poorly water soluble model drug (budesonide) was dissolved in chloroform, and the solution was atomized by electrospraying. Following this, the charged droplets were neutralized and dried in a drying chamber. The pressure in the drying chamber was varied. The dried particles were collected and analyzed. The pressure reduction had a slight impact on particle size distribution. The particles produced in reduced pressure turned out to be notably more porous than the particles produced in atmospheric pressure. The pressure reduction also affects the degree of crystallinity of the product. The dissolution of the particles produced in reduced pressures was faster to a certain extent than that of the particles produced in atmospheric pressure. A setup for electrospraying materials in a reduced pressure was presented. The pressure reduction had a notable impact on particle morphology. The possibilities to tailor the particle properties during electrospraying were studied.

  4. The Effect of High Pressure and Subzero Temperature on Gelation of Washed Cod and Salmon Meat. (United States)

    Malinowska-Pańczyk, Edyta; Kołodziejska, Ilona


    The objective of the present work is to examine the influence of pressure up to 193 MPa at subzero temperature (without freezing of water) on myofibrillar proteins of salmon and cod meat and on the properties of gels obtained from washed mince of these fish. The solubility of proteins from myofibrils of cod and salmon meat suspended in 100 mM KCl solution increased after treating the samples with pressure above 60 MPa. The results of SDS- -PAGE analysis showed that under these conditions two myosin light chains, tropomyosin and troponin T were released from myofibrils. The solubility of proteins in 0.9 M NaCl solution of washed fish meat after pressure treatment at 60 MPa and -5 °C decreased to about 80-90% and at 193 MPa and -20 °C to 60%. Pressurization of cod meat decreased only slightly the solubility of proteins in SDS and urea solution and the solubility of salmon meat was similar to that in the unpressurized sample. There were no differences in the electrophoretic pattern of proteins from untreated and pressurized cod and salmon meat in the range of 60 to 193 MPa and -5 to -20 °C. The pressure treatment of washed salmon and cod meat at a temperature below 0 °C induced gelation; on the other hand, hardness of gels was lower by 28 and 26%, respectively, than that of gels formed by heating. The salmon and cod gels pressurized at 193 MPa and -20 °C and then heated were much harder than only pressurized or heated gels.

  5. The effect of pressure and temperature on aluminium hydrolysis: Implications to trace metal scavenging in natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    Removal of aluminium through precipitation/scavenging in natural waters was evaluated based on its hydrolysis at different temperatures and pressures. In general, pH for the occurrence of cation hydrolysis was lowered with hike in temperature which...

  6. The use of β-glucan as a partial salt replacer in high pressure processed chicken breast meat. (United States)

    Omana, Dileep A; Plastow, Graham; Betti, Mirko


    The effect of various ingredients such as sodium chloride (NaCl), sodium tripolyphosphate (STPP) and β-glucan (BG) on the biochemical properties of chicken breast proteins during temperature assisted high pressure processing was studied. Total protein solubility revealed that 600MPa pressure and 40(o)C are critical for the denaturation of proteins in STPP samples. Increase in reactive sulfhydryl groups with pressure indicate the exposure of buried sulfhydryl groups. Hydrophobicity and sulfhydryl contents revealed that hydrophobic interaction and disulphide bond formation are responsible for gel formation. The study revealed that 40(o)C and 400/600MPa pressure is optimum for high pressure processing of chicken breast meat. Addition of β-glucan with reduced NaCl and in the absence of sodium tripolyphosphate could produce gels with similar properties to those with 2.5% NaCl addition. Hence it is proposed that β-glucan can be used to reduce NaCl content of chicken products produced by temperature assisted high pressure processing. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Stable Isolation of Phycocyanin from Spirulina platensis Associated with High-Pressure Extraction Process (United States)

    Seo, Yong Chang; Choi, Woo Seok; Park, Jong Ho; Park, Jin Oh; Jung, Kyung-Hwan; Lee, Hyeon Yong


    A method for stably purifying a functional dye, phycocyanin from Spirulina platensis was developed by a hexane extraction process combined with high pressure. This was necessary because this dye is known to be very unstable during normal extraction processes. The purification yield of this method was estimated as 10.2%, whose value is 3%–5% higher than is the case from another conventional separation method using phosphate buffer. The isolated phycocyanin from this process also showed the highest purity of 0.909 based on absorbance of 2.104 at 280 nm and 1.912 at 620 nm. Two subunits of phycocyanin namely α-phycocyanin (18.4 kDa) and β-phycocyanin (21.3 kDa) were found to remain from the original mixtures after being extracted, based on SDS-PAGE analysis, clearly demonstrating that this process can stably extract phycocyanin and is not affected by extraction solvent, temperature, etc. The stability of the extracted phycocyanin was also confirmed by comparing its DPPH (α,α-diphenyl-β-picrylhydrazyl) scavenging activity, showing 83% removal of oxygen free radicals. This activity was about 15% higher than that of commercially available standard phycocyanin, which implies that the combined extraction method can yield relatively intact chromoprotein through absence of degradation. The results were achieved because the low temperature and high pressure extraction effectively disrupted the cell membrane of Spirulina platensis and degraded less the polypeptide subunits of phycocyanin (which is a temperature/pH-sensitive chromoprotein) as well as increasing the extraction yield. PMID:23325046

  8. Stable isolation of phycocyanin from Spirulina platensis associated with high-pressure extraction process. (United States)

    Seo, Yong Chang; Choi, Woo Seok; Park, Jong Ho; Park, Jin Oh; Jung, Kyung-Hwan; Lee, Hyeon Yong


    A method for stably purifying a functional dye, phycocyanin from Spirulina platensis was developed by a hexane extraction process combined with high pressure. This was necessary because this dye is known to be very unstable during normal extraction processes. The purification yield of this method was estimated as 10.2%, whose value is 3%-5% higher than is the case from another conventional separation method using phosphate buffer. The isolated phycocyanin from this process also showed the highest purity of 0.909 based on absorbance of 2.104 at 280 nm and 1.912 at 620 nm. Two subunits of phycocyanin namely α-phycocyanin (18.4 kDa) and β-phycocyanin (21.3 kDa) were found to remain from the original mixtures after being extracted, based on SDS-PAGE analysis, clearly demonstrating that this process can stably extract phycocyanin and is not affected by extraction solvent, temperature, etc. The stability of the extracted phycocyanin was also confirmed by comparing its DPPH (α,α-diphenyl-β-picrylhydrazyl) scavenging activity, showing 83% removal of oxygen free radicals. This activity was about 15% higher than that of commercially available standard phycocyanin, which implies that the combined extraction method can yield relatively intact chromoprotein through absence of degradation. The results were achieved because the low temperature and high pressure extraction effectively disrupted the cell membrane of Spirulina platensis and degraded less the polypeptide subunits of phycocyanin (which is a temperature/pH-sensitive chromoprotein) as well as increasing the extraction yield.

  9. Stable Isolation of Phycocyanin from Spirulina platensis Associated with High-Pressure Extraction Process

    Directory of Open Access Journals (Sweden)

    Kyung-Hwan Jung


    Full Text Available A method for stably purifying a functional dye, phycocyanin from Spirulina platensis was developed by a hexane extraction process combined with high pressure. This was necessary because this dye is known to be very unstable during normal extraction processes. The purification yield of this method was estimated as 10.2%, whose value is 3%–5% higher than is the case from another conventional separation method using phosphate buffer. The isolated phycocyanin from this process also showed the highest purity of 0.909 based on absorbance of 2.104 at 280 nm and 1.912 at 620 nm. Two subunits of phycocyanin namely α-phycocyanin (18.4 kDa and β-phycocyanin (21.3 kDa were found to remain from the original mixtures after being extracted, based on SDS-PAGE analysis, clearly demonstrating that this process can stably extract phycocyanin and is not affected by extraction solvent, temperature, etc. The stability of the extracted phycocyanin was also confirmed by comparing its DPPH (α,α-diphenyl-β-picrylhydrazyl scavenging activity, showing 83% removal of oxygen free radicals. This activity was about 15% higher than that of commercially available standard phycocyanin, which implies that the combined extraction method can yield relatively intact chromoprotein through absence of degradation. The results were achieved because the low temperature and high pressure extraction effectively disrupted the cell membrane of Spirulina platensis and degraded less the polypeptide subunits of phycocyanin (which is a temperature/pH-sensitive chromoprotein as well as increasing the extraction yield.

  10. Driving force for indentation cracking in glass: composition, pressure and temperature dependence (United States)

    Rouxel, Tanguy


    The occurrence of damage at the surface of glass parts caused by sharp contact loading is a major issue for glass makers, suppliers and end-users. Yet, it is still a poorly understood problem from the viewpoints both of glass science and solid mechanics. Different microcracking patterns are observed at indentation sites depending on the glass composition and indentation cracks may form during both the loading and the unloading stages. Besides, we do not know much about the fracture toughness of glass and its composition dependence, so that setting a criterion for crack initiation and predicting the extent of the damage yet remain out of reach. In this study, by comparison of the behaviour of glasses from very different chemical systems and by identifying experimentally the individual contributions of the different rheological processes leading to the formation of the imprint—namely elasticity, densification and shear flow—we obtain a fairly straightforward prediction of the type and extent of the microcracks which will most likely form, depending on the physical properties of the glass. Finally, some guidelines to reduce the driving force for microcracking are proposed in the light of the effects of composition, temperature and pressure, and the areas for further research are briefly discussed. PMID:25713446

  11. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.


    The need for highly accurate thermal property data for a broad range of new application fluids is well documented. To facilitate expansion of the current thermophysical database, an automated flow calorimeter was developed for the measurement of highly accurate isobaric heat capacities and enthalpies of fluids at elevated temperatures and pressures. The experimental technique utilizes traditional electrical power input, adiabatic flow calorimetry with a precision metering pump that eliminates the need for on-line flow rate monitoring. In addition, a complete automation system, greatly simplifies the operation of the apparatus and increases the rapidity of the measurement process. The range over which the instrument was tested, was 300--600 K and 0--12 Mpa, although the calorimeter should perform up to the original design goals of 700 K and 30 MPa. The new flow calorimeter was evaluated by measuring the mean, isobaric, specific heat capacities of liquid water and n-pentane. These experiments yielded an average deviation from the standard literature data of +0.02% and a total variation of 0.05%. Additional data analysis indicated that the overall measurement uncertainty was conservatively estimated as 0.2% with an anticipated precision of 0.1--0.15% at all operating conditions. 44 refs., 27 figs., 2 tabs.

  12. Silicon Carbide Temperature Monitor Processing Improvements. Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Unruh, Troy Casey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daw, Joshua Earl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Al Rashdan, Ahamad [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Silicon carbide (SiC) temperature monitors are used as temperature sensors in Advanced Test Reactor (ATR) irradiations at the Idaho National Laboratory (INL). Although thermocouples are typically used to provide real-time temperature indication in instrumented lead tests, other indicators, such as melt wires, are also often included in such tests as an independent technique of detecting peak temperatures incurred during irradiation. In addition, less expensive static capsule tests, which have no leads attached for real-time data transmission, often rely on melt wires as a post-irradiation technique for peak temperature indication. Melt wires are limited in that they can only detect whether a single temperature is or is not exceeded. SiC monitors are advantageous because a single monitor can be used to detect for a range of temperatures that occurred during irradiation. As part of the process initiated to make SiC temperature monitors available at the ATR, post-irradiation evaluations of these monitors have been previously completed at the High Temperature Test Laboratory (HTTL). INL selected the resistance measurement approach for determining irradiation temperature from SiC temperature monitors because it is considered to be the most accurate measurement. The current process involves the repeated annealing of the SiC monitors at incrementally increasing temperature, with resistivity measurements made between annealing steps. The process is time consuming and requires the nearly constant attention of a trained staff member. In addition to the expensive and lengthy post analysis required, the current process adds many potential sources of error in the measurement, as the sensor must be repeatedly moved from furnace to test fixture. This time-consuming post irradiation analysis is a significant portion of the total cost of using these otherwise inexpensive sensors. An additional consideration of this research is that, if the SiC post processing can be automated, it

  13. Seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese studied by home measurements. (United States)

    Kimura, Toshiaki; Senda, Shoichi; Masugata, Hisashi; Yamagami, Ayumu; Okuyama, Hiroyuki; Kohno, Takeaki; Hirao, Tomohiro; Fukunaga, Megumu; Okada, Hiroki; Goda, Fuminori


    The purpose of the present study was to examine seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese, as studied by home measurements. Fifteen healthy elderly Japanese (79.3 +/- 5.9 yrs) measured their blood pressure at home each morning for more than 25 times per month for 3 years. Monthly mean outdoor temperatures were obtained from the Takamatsu meteorological Observatory. The highest levels of systolic and diastolic blood pressure measured at home were observed in February (129 +/- 14 and 81 +/- 13 mmHg). The lowest levels of systolic and diastolic blood pressure measured at home were observed in August (117 +/- 11 and 73 +/- 10 mmHg). Likewise, the lowest and highest means of outdoor temperature were observed in February (5.0 degrees C) and August (29.2 degrees C), respectively. Hence, both systolic and diastolic blood pressure demonstrated a close inverse correlation with the means of outdoor temperature (r = -0.973, p blood pressure (SBP) and 0.29 mmHg in diastolic blood pressure (DBP). Seasonal variations in home blood pressure and outdoor temperature showed complete correspondence in healthy elderly Japanese, with the blood pressures being inversely related to the ambient temperature. These seasonal home blood pressure variations should be kept in mind when controlling blood pressure in elderly patients.

  14. Influence of cell integrity on textural properties of raw, high pressure, and thermally processed onions. (United States)

    Gonzalez, M E; Jernstedt, J A; Slaughter, D C; Barrett, D M


    The integrity of onion cells and its impact on tissue texture after high pressure and thermal processing was studied. The contribution of cell membranes and the pectic component of cell walls on the texture properties of onion tissue were analyzed. Neutral red (NR) staining of onion parenchyma cell vacuoles was used for the evaluation of cell membrane integrity and microscopic image analysis was used for its quantification. The content of methanol in tissue as a result of pectin methylesterase activity was used to evaluate the pectin component of the middle lamella and cell walls and the hardening effect on the tissue after processing. High pressure treatments consisted of 5-min holding times at 50, 100, 200, 300, or 600 MPa. Thermal treatments consisted of 30-min water bath exposure to 40, 50, 60, 70, or 90 °C. In the high pressure treatments, loss of membrane integrity commenced at 200 MPa and total loss of membrane integrity occurred at 300 MPa and above. In the thermal treatments, membrane integrity was lost between 50 and 60 °C. The texture of onions was influenced by the state of the membranes and texture profiles were abruptly modified once membrane integrity was lost. Hardening of the tissue corresponded with pressure and temperature PME activation and occurred after membrane integrity loss. The texture of vegetables is an important quality attribute that affects consumer preference. Loss of textural integrity also indicates that other biochemical reactions that affect color, flavor, and nutrient content may occur more rapidly. In this study, we analyzed changes in the texture of onions after preservation with heat and high pressure.

  15. Thermal conductivity and diffusivity of climax stock quartz monzonite at high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B.; Abey, A.E.


    Measurements of thermal conductivity and thermal diffusivity have been made on two samples of Climax Stock quartz monzonite at pressures between 3 and 50 MPa and temperatures between 300 and 523{sup 0}K. Following those measurements the apparatus was calibrated with respect to the thermal conductivity measurement using a reference standard of fused silica. Corrected thermal conductivity of the rock indicates a value at room temperature of 2.60 +- 0.25 W/mK at 3 MPa increasing linearly to 2.75 +- 0.25 W/mK at 50 MPa. These values are unchanged (+- 0.07 W/mK) by heating under 50-MPa pressure to as high as 473{sup 0}K. The conductivity under 50-MPa confining pressure falls smoothly from 2.75 +- 0.25 W/mK at 313{sup 0}K to 2.15 +- 0.25 W/mK at 473{sup 0}K. Thermal diffusivity at 300{sup 0}K was found to be 1.2 +- 0.4 X 10{sup -6} m{sup 2}/s and shows approximately the same pressure and temperature dependencies as the thermal conductivity.

  16. 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.

  17. Referenced dual pressure- and temperature-sensitive paint for digital color camera read out. (United States)

    Fischer, Lorenz H; Karakus, Cüneyt; Meier, Robert J; Risch, Nikolaus; Wolfbeis, Otto S; Holder, Elisabeth; Schäferling, Michael


    The first fluorescent material for the referenced simultaneous RGB (red green blue) imaging of barometric pressure (oxygen partial pressure) and temperature is presented. This sensitive coating consists of two platinum(II) complexes as indicators and a reference dye, each of which is incorporated in appropriate polymer nanoparticles. These particles are dispersed in a polyurethane hydrogel and spread onto a solid support. The emission of the (oxygen) pressure indicator, PtTFPP, matches the red channel of a RGB color camera, whilst the emission of the temperature indicator [Pt(II) (Br-thq)(acac)] matches the green channel. The reference dye, 9,10-diphenylanthracene, emits in the blue channel. In contrast to other dual-sensitive materials, this new coating allows for the simultaneous imaging of both indicator signals, as well as the reference signal, in one RGB color picture without having to separate the signals with additional optical filters. All of these dyes are excitable with a 405 nm light-emitting diode (LED). With this new composite material, barometric pressure can be determined with a resolution of 22 mbar; the temperature can be determined with a resolution of 4.3 °C. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. First-principles calculations of high-pressure and -temperature properties of stishovite (United States)

    Yang, R.; Wu, Z.


    Quartz is one of the main gradient of the crust and is transformed into coesite and then stishovite under pressure. Stishovite is stable at 9~50GPa [1,2]. It is estimated that stishovite makes up more than 20% of the subducted oceanic crust in the mantle transition zone and lower mantle [3,4,5]. Therefore, the properties of stishovite under high-pressure and -temperature are very critical for us to understand the mantle convection. We investigated themodynamic properties of stishovite by combing first-principles calculations with quasi-hamonic approximation. We also calculated the elastic constants of stishovite at high-temperature and -pressure using the new method developed by Wu and Wentzcovitch [6]. The calculated results are in consistence with the experimental data. Both temperature and pressure significantly affect the anistropy of the stishovite. 1, Zhang, J., Li, B., Utsumi, W., Liebermann, R. C., Phys. Chem. Miner., 23, 1-10 (1996) 2, Kingma, K. J., R. E. Cohen, R. J. Hemley, and H. K. Mao, Nature, 374, 243-245 (1995). 3. Kesson, S. E., Fitz Gerald, J. D. Shelley, J. M. G., Nature, 372,767-769 (1994) 4, Ono, S., Ito, E., Katsura, T., Earth Planet. Sci. Lett., 190, 57-63 (2001) 5, Irifue, T., Ringwood, A. E., Earth Planet. Sci. Lett., 117, 101-110 (1993) 6, Wu, Z., Wentzcovitch, R. M., Phys. Rev. B 83, 184115 (2011)

  19. Density of phonon states in superconducting FeSe as a function of temperature and pressure (United States)

    Ksenofontov, V.; Wortmann, G.; Chumakov, A. I.; Gasi, T.; Medvedev, S.; McQueen, T. M.; Cava, R. J.; Felser, C.


    The temperature and pressure dependence of the partial density of phonon states (phonon-DOS) of iron atoms in superconducting Fe1.01Se was studied by F57e nuclear inelastic scattering. The high-energy resolution allows for a detailed observation of spectral properties. A sharpening of the optical phonon modes and shift of all spectral features toward higher energies by ˜4% with decreasing temperature from 296 to 10 K was found. However, no detectable change at the tetragonal-orthorhombic phase transition around 100 K was observed. Application of a pressure of 6.7 GPa, connected with an increase in the superconducting temperature from 8 to 34 K, results in an increase in the optical phonon mode energies at 296 K by ˜12% , and an even more pronounced increase for the lowest-lying transversal acoustic mode. Despite these strong pressure-induced modifications of the phonon-DOS we conclude that the pronounced increase in Tc in Fe1.01Se with pressure cannot be described in the framework of classical electron-phonon coupling. This result suggests the importance of spin fluctuations to the observed superconductivity.

  20. Temperature sensitivity of organic compound destruction in SCWO process. (United States)

    Tan, Yaqin; Shen, Zhemin; Guo, Weimin; Ouyang, Chuang; Jia, Jinping; Jiang, Weili; Zhou, Haiyun


    To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process (SCWO), oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve (imax) was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds (imax > 0.25) can be completely oxidized when the reactor temperature reaches 500°C. However, some compounds (imax > 0.25) need a higher temperature for complete oxidation, up to 560°C. To analyze the correlation coefficients between imax and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  1. Partitioning of siderophile elements between metallic liquids and silicate liquids under high-pressure and temperature (United States)

    Nakatsuka, A.; Urakawa, S.


    High-pressure metal-silicate element partitioning studies have shown the possibility that the mantle abundance of siderophile elements is consistent with core-mantle equilibration at high pressures and high temperatures. Equilibrium conditions are, however, still under debates partly due to the uncertainty of partition coefficients, which vary not only with pressure, temperature and oxygen fugacity but also with composition. We have carried out partitioning experiments of siderophile elements between liquid metal and ultramafic silicate liquid at high pressure to evaluate the effects of composition on the partition coefficients. Partitioning experiments were conducted by KAWAI-type high pressure apparatus. We used natural peridotite and Fe alloy as starting materials and they were contained in graphite capsule. The quenched samples were examined by electron microprobe. Quenched textures indicate that metallic melts coexisted with silicate melts during experiment. The metallic melt contained 7-9 wt% of C. Oxygen fugacity varied from IW-3 to IW-1 in associated with the composition of the starting material. At the reduced condition, silicate melt was enriched in SiO2 compared to peridotite because of the oxidation of Si in metallic melts. When oxygen fugacity is close to IW buffur, silicate melt was enriched in FeO due to the oxidation of metallic Fe and it had high NBO/T = 3.5-4. The partition coefficients D for Co, Ni and Fe were dependent on oxygen fugacity as well as the chemical compositions.


    Directory of Open Access Journals (Sweden)

    R. Hamidova


    Full Text Available Abstract Pressure-density-temperature (p, ρ ,T data of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide [BMIM][NTF2] at T = (273.15 to 413.15 K and pressures up to p =140 MPa are reported with an estimated experimental relative combined standard uncertainty of Δ ρ / ρ = ±(0.01 to 0.08% in density. The measurements were carried out with a newly constructed Anton-Paar DMA HPM vibration-tube densimeter. The system was calibrated using double-distilled water, aqueous NaCl solution, methanol, toluene and acetone. An empirical equation of state for fitting the (p, ρ ,T data of [BMIM][NTF2] has been developed as a function of pressure and temperature. This equation is used for the calculation of the thermophysical properties of the ionic liquid, such as isothermal compressibility, isobaric thermal expansibility, thermal pressure coefficient, internal pressure, isobaric and isochoric heat capacities, speed of sound and isentropic expansibility.

  3. Temperature-Compensated Force/Pressure Sensor Based on Multi-Walled Carbon Nanotube Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Nghia Trong Dinh


    Full Text Available In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.

  4. [Measurements of CO2 concentration at high temperature and pressure environments using tunable diode laser absorption spectroscopy]. (United States)

    Cai, Ting-Dong; Gao, Guang-Zhen; Wang, Min-Rui; Wang, Gui-Shi; Gao, Xiao-Ming


    The present research was planned to develop a method for species concentration measurements under high temperature and pressure environments. The characteristics of CO2 spectrum at high temperature and pressure were studied at first. Based on the research above, tunable diode-laser absorption of CO2 near 2.0 microm incorporating fixed-wavelength modulation spectroscopy with second-harmonic detection was used to provide a method for sensitive and accurate measurements of gas temperature and CO2 concentration at high temperature and pressure. Measurements were performed in a well-controlled high temperature and pressure static cell. The results show that the average error of the CO2 concentration measurements at 5 atm, 500 K and 10 atm, 1000 K is 4. 49%. All measurements show the accuracy and potential utility of the method for high temperature and pressure diagnostics.

  5. Grain size and microhardness evolution during annealing of a magnesium alloy processed by high-pressure torsion

    Directory of Open Access Journals (Sweden)

    Livia Raquel C. Malheiros


    Full Text Available High-pressure torsion (HPT was used to impose severe plastic deformation on a magnesium alloy AZ31. The material was processed for 0.5, 1, 2, 3, 5 and 7 turns at room temperature under a pressure of 6.0 GPa. Samples were annealed for 1800 s at temperatures of 373 K, 423 K, 473 K, 573 K and 673 K. Microhardness tests and metallography were used to determine the evolution of strength and grain size as a function of the annealing temperature. The results show that recrystallization takes place at temperatures higher than 423 K. The annealing behavior is independent of the number of turns in HPT.

  6. A new retrieval algorithm for tropospheric temperature, humidity and pressure profiling based on GNSS radio occultation data (United States)

    Kirchengast, Gottfried; Li, Ying; Scherllin-Pirscher, Barbara; Schwärz, Marc; Schwarz, Jakob; Nielsen, Johannes K.


    The GNSS radio occultation (RO) technique is an important remote sensing technique for obtaining thermodynamic profiles of temperature, humidity, and pressure in the Earth's troposphere. However, due to refraction effects of both dry ambient air and water vapor in the troposphere, retrieval of accurate thermodynamic profiles at these lower altitudes is challenging and requires suitable background information in addition to the RO refractivity information. Here we introduce a new moist air retrieval algorithm aiming to improve the quality and robustness of retrieving temperature, humidity and pressure profiles in moist air tropospheric conditions. The new algorithm consists of four steps: (1) use of prescribed specific humidity and its uncertainty to retrieve temperature and its associated uncertainty; (2) use of prescribed temperature and its uncertainty to retrieve specific humidity and its associated uncertainty; (3) use of the previous results to estimate final temperature and specific humidity profiles through optimal estimation; (4) determination of air pressure and density profiles from the results obtained before. The new algorithm does not require elaborated matrix inversions which are otherwise widely used in 1D-Var retrieval algorithms, and it allows a transparent uncertainty propagation, whereby the uncertainties of prescribed variables are dynamically estimated accounting for their spatial and temporal variations. Estimated random uncertainties are calculated by constructing error covariance matrices from co-located ECMWF short-range forecast and corresponding analysis profiles. Systematic uncertainties are estimated by empirical modeling. The influence of regarding or disregarding vertical error correlations is quantified. The new scheme is implemented with static input uncertainty profiles in WEGC's current OPSv5.6 processing system and with full scope in WEGC's next-generation system, the Reference Occultation Processing System (rOPS). Results from

  7. Study on copper kinetics in processing sulphide ore mixed with copper and zinc with sulfuric acid leaching under pressure (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN


    Sulphide ore mixed with copper and zinc is processed with pressure acid leaching. Research is conducted on the copper kinetic. The stirring rate is set at 600 rpm which could eliminate the influence of external diffusions. Research is conducted on the factors affecting the copper leaching kinetic are temperature, pressure, concentration of sulfuric acid, particle size. The result shows that the apparent activity energy is 50.7 KJ/mol. We could determine that the copper leaching process is shrinking core model of chemical reaction control and work out the leaching equation.

  8. Analyzing the temperature control of steam purging of 660mw ultra-supercritical once-through boiler with pressure-reducing method (United States)

    Wu, Ying; Zhong, Yong-lu; Liu, Fa-sheng; Chen, Wen; Gui, Liang-ming; Xia, Yong-jun; Wan, Zhong-hai; Yan, Tao


    This paper generally introduced the process of steam purging of the ultra-supercritical once-through boiler of Jiangxi Xinchang 2×660MW Power Plant with the pressure-reducing method. In this paper, the key-points of steam temperature control was importantly analyzed and summarized. The success experience can provide the reference for preventing steam overtemp of the similar ultra-supercritical once-through boilers with pressure-reducing method.

  9. The preparation of calcium superoxide at subambient temperatures and pressures. [oxygen source for breathing apparatus (United States)

    Ballou, E. V.; Wood, P. C.; Spitze, L. A.; Wydeven, T.; Stein, R.


    The effects of disproportionations at lower temperatures and also of a range of reaction chamber pressures on the preparation of calcium superoxide, Ca(O2)2, from calcium peroxide diperoxyhydrate were studied. About 60% purity of product was obtained by a disproportionation procedure. The significance of features of this procedure for a prospective scale-up of the mass prepared in a single experiment is considered. The optimum pressure for product purity was determined, and the use of a molecular sieve desiccant is described.

  10. Piezoresistive pressure sensors in CVD diamond for high-temperature applications (United States)

    Otterbach, Ralf; Hilleringmann, Ulrich


    The fabrication of piezo-resistive pressure sensors for high temperature applications by the selective removal of CVD-diamond is limited due to the jutting physical properties of this material, which result in insufficient etching rates. A novel technique with distinctly increased etching rates due to a modified sample arrangement inside of a commercially available reactive ion etching (RIE) reactor overcomes this limitation by a restricted plasma volume. Rates up to 334 nm/min imply an increase of more than one order of magnitude in comparison with additional measurements utilizing a standard etching technique. Furthermore, the electrical response of a fabricated sensor on pressure is demonstrated.

  11. Heat transfer resistances in the measurements of cold helium vapour temperature in a subatmospheric process line (United States)

    Adamczyk, A.; Pietrowicz, S.; Fydrych, J.


    The superfluid helium technology, which is essentially used in particle accelerators, requires complex cryogenic systems that include long lines transferring cold helium vapours at a subathmospheric pressure below 50 mbar. Usually in large systems the subatmospheric pressure is generated by a set of warm and cold compressors. In consequence, the heat loads to the line and especially the helium temperature in the inlet to the cold compressors are crucial parameters. In order to measure the helium temperature the temperature sensors are usually fixed to the external surface of the process lines. However, this technique can lead to unwanted measurement errors and affect the temperature measurement dynamics mainly due to low thermal conductivity of the pipe wall material, large pipe diameters and low helium density. Assembling a temperature sensor in a well (cold finger) reaching the centerline of the flowing helium is a technique that can improve the measurement quality and dynamics (response time). The paper presents the numerical simulations of heat transfers occurring in the both measurement techniques and discusses the impacts of the heat transfer resistances on the temperature measurement dynamics.

  12. Effects of pressure and temperature on the carrier transports in organic crystal: A first-principles study (United States)

    Wang, L. J.; Li, Q. K.; Shuai, Z.


    By employing density-functional theory coupled with Holstein-Peierls model, we investigate the pressure and temperature dependence of the hole and electron mobilities in naphthalene single crystal from atmospheric pressure up to 2.1GPa (at room temperature) and from 5to296K (at ambient pressure). It is found that the pressure reduces the electron-phonon coupling strength and enhances the mobilities. Importantly, we point out that only when temperature-dependent structure modifications are taken into account can one better describe the temperature-dependent transport behavior. Especially, the band to hopping crossover transition temperature for the electron transport in the c'-axis is calculated to be around 153K, which is close to the experimental result of between 100 and 150K. If this temperature-dependent structure modifications were neglected, the transition temperature would be only about 23K, as previously obtained [L. J. Wang et al., J. Chem. Phys. 127, 044506 (2007)].

  13. Atmospheric Pressure Plasma-Electrospin Hybrid Process for Protective Applications (United States)

    Vitchuli Gangadharan, Narendiran


    -level aerosol chemical and biological threats. Polymer solution concentration, electrospinning voltage, and deposition areal density were varied to establish the relationship of processing-structure-filtration efficiency for electrospun fiber mats. A high barrier efficiency of greater than 99.5% was achieved on electrospun fiber mats without sacrificing air permeability and pressure drop. ii) Fabrication and Characterization of Multifunctional ZnO/Nylon 6 nanofibers ZnO/Nylon 6 nanofiber mats were prepared by an electrospinning-electrospraying hybrid process, The electrospinning of polymer solution and electrospraying of ZnO particles were carried out simultaneously such that the ZnO nanoparticles were dispersed on the surface of Nylon 6 nanofibers. The prepared ZnO/Nylon 6 nanofiber mats were tested for detoxifying characteristics against simulants of C-B agents. The results showed that ZnO/Nylon 6 functional nanofiber mats exhibited good detoxification action against paraoxon and have antibacterial efficiency over 99.99% against both the gram-negative E. coli and gram positive B. cereus bacteria. iii) Improving adhesion of electrospun nanofiber mat onto woven fabric by plasma pretreatment of substrate fabric and plasma-electrospinning hybrid process Electrospun nanofibers were deposited onto plasma-pretreated woven fabric to improve the adhesion. In addition, the plasma-electrospinning hybrid process was developed and used in which the nanofibers were subjected to in-situ plasma treatment during electrospinning. The effects of plasma treatement on substrate fabric and electrospun fibers were characterized by water contact angle test, XPS analyses. The improvement of nanofiber adhesive properties on fabric substrate was evaluated by peel test, flex resistance test and abrasion resistance test. The test results showed that the plasma treatment caused introduction of active chemical groups on substrate fabric and electrospun nanofibers. These active chemical assisted in possible

  14. High Temperature Epoxy Foam: Optimization of Process Parameters

    Directory of Open Access Journals (Sweden)

    Samira El Gazzani


    Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

  15. Central inhibitory effect of α-methyldopa on blood pressure, heart rate and body temperature of renal hypertensive rats

    NARCIS (Netherlands)

    Nijkamp, F.P.; Ezer, Joseph; Jong, Wybren de

    The central inhibitory effect of α-methyldopa on blood pressure, heart rate and body temperature was studied in conscious renal hypertensive rats. Systemic administration of α-methyldopa decreased mean arterial blood pressure and body temperature and caused a short lasting increase in heart rate

  16. A Simple Mercury-Free Laboratory Apparatus to Study the Relationship between Pressure, Volume, and Temperature in a Gas (United States)

    McGregor, Donna; Sweeney, William V.; Mills, Pamela


    A simple and inexpensive mercury-free apparatus to measure the change in volume of a gas as a function of pressure at different temperatures is described. The apparatus is simpler than many found in the literature and can be used to study variations in pressure, volume, and temperature. (Contains 1 table and 7 figures.)

  17. Spectroscopy for Industrial Applications: High-Temperature Processes

    DEFF Research Database (Denmark)

    Fateev, Alexander; Grosch, Helge; Clausen, Sønnik

    The continuous development of the spectroscopic databases brings new perspectives in the environmental and industrial on-line process control, monitoring and stimulates further optical sensor developments. This is because no calibration gases are needed and, in general, temperature-dependent spec...

  18. RF transconductor linearization robust to process, voltage and temperature variations

    NARCIS (Netherlands)

    Kundur Subramaniyan, H.; Klumperink, Eric A.M.; Srinivasan, Venkatesh; Kiaei, Ali; Nauta, Bram


    Software-defined radio receivers increasingly exploit linear RF V-I conversion, instead of RF voltage gain, to improve interference robustness. Unfortunately, the linearity of CMOS inverters, which are often used to implement V-I conversion, is highly sensitive to Process, Voltage and Temperature

  19. A seeded ambient temperature ferrite process for treatment of AMD ...

    African Journals Online (AJOL)

    Abstract. An ambient temperature ferrite process has been developed for the removal of iron and non-ferrous metals from AMD waters. ... It was found that in order to attain the required high Fe2+:Ca2+ ratio, the solid ferrous-hydroxy species concentration in the oxidation reactor should be maintained at above 1 200 mg Fe/l.

  20. Analysis of an Intelligent Temperature Transmitter for Process Control

    African Journals Online (AJOL)

    It also identifies low power microprocessor and analog to digital converters working with the basic sensor circuit as the key propellants in the advancement of transmitter technology. Despite several sensors available in the process control industry, the authors focus on temperature sensors and analyze a typical Rosemount ...

  1. Adsorption of Molecular Gases on Silver/Carbon Nanotube Composites at Low Temperatures and Low Pressures

    Directory of Open Access Journals (Sweden)

    M. Barberio


    Full Text Available We present an experimental study adsorption of molecular gases (N2, H2, O2, CH4, C2H4, and C2H6 on multiwalled carbon nanotubes (MWCNTs and MWCNT doped with Ag at low temperatures (35 K and pressures (10−6 Torr using the temperature programmed desorption technique. Our results show that the desorption kinetics is of the first order; furthermore comparative measurements indicate that Ag/MWCNTs have an adsorption capacity higher than that of a pure sample suggesting that these composites are good candidates as gas cryosorbers for applications in cryopumps or sensor of latest generation.

  2. Laser-Doppler vibrating tube densimeter for measurements at high temperatures and pressures. (United States)

    Aida, Tsutomu; Yamazaki, Ai; Akutsu, Makoto; Ono, Takumi; Kanno, Akihiro; Hoshina, Taka-aki; Ota, Masaki; Watanabe, Masaru; Sato, Yoshiyuki; Smith, Richard L; Inomata, Hiroshi


    A laser-Doppler vibrometer was used to measure the vibration of a vibrating tube densimeter for measuring P-V-T data at high temperatures and pressures. The apparatus developed allowed the control of the residence time of the sample so that decomposition at high temperatures could be minimized. A function generator and piezoelectric crystal was used to excite the U-shaped tube in one of its normal modes of vibration. Densities of methanol-water mixtures are reported for at 673 K and 40 MPa with an uncertainty of 0.009 g/cm3.

  3. Patterns in new dimensionless quantities containing melting temperature, and their dependence on pressure

    Directory of Open Access Journals (Sweden)



    Full Text Available The relationships existing between melting temperature and other
    macroscopic physical quantities are investigated. A new dimensionless
    quantity Q(1 not containing the Grtineisen parameter proves to be suited for serving in future studies as a tool for the determination of the melting temperature in the outer core of the Earth. The pressure dependence of more general dimensionless quantities Q„ is determined analytically and, for the chemical elements, numerically, too. The patterns of various interesting dimensionless quantities are shown in the Periodic Table and compared.

  4. Integrated LTCC pressure/flow/temperature multisensor for compressed air diagnostics. (United States)

    Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter


    We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  5. Simulation of changes in temperature and pressure fields during high speed projectiles forming by explosion

    National Research Council Canada - National Science Library

    Marković Miloš D; Milinović Momčilo P; Jeremić Olivera M; Jaramaz Slobodan S


    The Research in this paper considered the temperatures fields as the consequently influenced effects appeared by plastic deformation, in the explosively forming process aimed to design Explosively Formed Projectiles (henceforth EFP...

  6. Prediction of Pressure and Temperature Gradients in the Tokamak Plasma Edge (United States)

    Stacey, W. M.


    An extended plasma fluid theory that takes into account kinetic ion orbit loss and electromagnetic forces in the continuity, momentum and energy balances, as well as atomic physics and radiation, has been used to reveal the explicit dependence of the temperature and pressure gradients in the tokamak edge plasma on these various factors. Combining the ion radial momentum balance and the Ohm's Law expression for Er reveals the dependence of the radial ion pressure gradient on VxB forces driven by radial particle fluxes, which depend on ion orbit loss, and other factors. The strong temperature gradients measured in the H-mode edge pedestal could certainly be associated with radiative and atomic physics edge cooling effects and the strong reduction in ion and energy fluxes due to ion orbit loss, as well as to the possible reductions in thermal diffusivities that is usually assumed to be the cause. Work supported by USDOE under DE-FC02-04ER54698.

  7. Design and analysis of a high pressure and high temperature sulfuric acid experimental system

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung-Deok, E-mail: [Korea Atomic Energy Research Institute, Yuseong-Gu, Daejeon 305-600 (Korea, Republic of); Kim, Chan-Soo; Kim, Yong-Wan [Korea Atomic Energy Research Institute, Yuseong-Gu, Daejeon 305-600 (Korea, Republic of); Seo, Dong-Un; Park, Goon-Cherl [Seoul National University, San56-1, Sillim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of)


    We discuss the design and analysis of a small scale sulfuric acid experimental system that can simulate a part of the hydrogen production module. Because nuclear hydrogen coupled components such as a SO{sub 3} decomposer and a sulfuric acid evaporator should be tested under high pressure and high temperature operating conditions, we developed the sulfuric acid loop to satisfy design specifications of 900 Degree-Sign C in temperature and 1.0 MPa in pressure. The components for the sulfuric acid loop were specially designed using a combination of materials with good corrosion resistance; a ceramic and Hastelloy-C276. The design feature of the loop was tested for performance in a 10 h sulfuric acid experiment and optimized using Aspen+ code simulation.

  8. The influence of temperature, pressure, salinity and capillary force on the formation of methane hydrate

    Directory of Open Access Journals (Sweden)

    Zhenhao Duan


    Full Text Available We present here a thermodynamic model for predicting multi-phase equilibrium of methane hydrate liquid and vapor phases under conditions of different temperature, pressure, salinity and pore sizes. The model is based on the 1959 van der Waals–Platteeuw model, angle-dependent ab initio intermolecular potentials, the DMW-92 equation of state and Pitzer theory. Comparison with all available experimental data shows that this model can accurately predict the effects of temperature, pressure, salinity and capillary radius on the formation and dissociation of methane hydrate. Online calculations of the p–T conditions for the formation of methane hydrate at given salinities and pore sizes of sediments are available on:

  9. Origin of the critical temperature discontinuity in superconducting sulfur under high pressure (United States)

    Monni, M.; Bernardini, F.; Sanna, A.; Profeta, G.; Massidda, S.


    Elemental sulfur shows a superconducting phase at high pressure (above 100 GPa), with critical temperatures that rise up to 20 K [Phys. Rev. B 65, 064504 (2002), 10.1103/PhysRevB.65.064504; Nature (London) 525, 73 (2015), 10.1038/nature14964] and presenting a jump at about 160 GPa, close to a structural phase transition to the β -Po phase. In this work we present a theoretical and fully ab initio characterization of sulfur based on superconducting density functional theory (SCDFT), focusing in the pressure range from 100 to 200 GPa. Calculations result in very good agreement with available experiments and point out that the origin of the critical temperature discontinuity is not related to the structural phase transition but induced by an electronic Lifshitz transition. This brings a strongly (interband) coupled electron pocket available for the superconducting condensation.

  10. Refractive-index and absorption fluctuations in the infrared caused by temperature, humidity, and pressure fluctuations (United States)

    Hill, R. J.; Clifford, S. F.; Lawrence, R. S.


    The dependence of fluctuations in atmospheric absorption and refraction upon fluctuations in temperature, humidity, and pressure is found for infrared frequencies. This dependence has contributions from line and continuum absorption and from anomalous refraction by water vapor. The functions that relate these fluctuations are necessary for evaluating degradation of electromagnetic radiation by turbulence. They are computed for a given choice of mean atmospheric conditions and graphed as functions of frequency in the wavelength range 5.7 microns to radio waves. It is found that turbulent fluctuations in total pressure give a negligible contribution to absorption and refraction fluctuations. Humidity fluctuations dominate absorption fluctuations, but contributions by temperature and humidity affect refraction fluctuations. Sufficiently strong humidity fluctuations can dominate the refraction fluctuations for some infrared frequencies but not for visible frequencies. The variance of log amplitude is examined for scintillation of infrared light to determine whether absorption or refraction fluctuations dominate under several conditions.

  11. Optical windows for a flow cell to contain aqueous solutions at high pressure and temperature (United States)

    Bowers, W. J., Jr.; Bean, V. E.; Hurst, W. S.


    A flow cell to contain aqueous solutions at pressures up to 40 MPa and temperatures up to 600 °C that is equipped with sapphire windows for the transmission of visible light is described. There are four windows, two for the entrance and exit of a laser beam, and two located at 90° that feature f/1 (53° included angle) collection apertures with a 9 mm diameter unobstructed view for Raman spectroscopy, absorption measurements, or studies using full-field back illumination. The window-to-metal seals are gold o-rings; the metal-to-metal seals are gaskets prepared by pressing a gold o-ring onto a gold foil washer. This cell has been used for two years for Raman studies of aqueous solutions at high pressures and temperatures both below and above the supercritical point of water.

  12. Pressure- and Temperature-Sensitive Paint at 0.3-m Transonic Cryogenic Tunnel (United States)

    Watkins, A. Neal; Leighty, Bradley D.; Lipford, William E.; Goodman, Kyle Z.


    Recently both Pressure- and Temperature-Sensitive Paint experiments were conducted at cryogenic conditions in the 0.3-m Transonic Cryogenic Tunnel at NASA Langley Research Center. This represented a re-introduction of the techniques to the facility after more than a decade, and provided a means to upgrade the measurements using newer technology as well as demonstrate that the techniques were still viable in the facility. Temperature-Sensitive Paint was employed on a laminar airfoil for transition detection and Pressure-Sensitive Paint was employed on a supercritical airfoil. This report will detail the techniques and their unique challenges that need to be overcome in cryogenic environments. In addition, several optimization strategies will also be discussed.

  13. High-pressure, ambient temperature hydrogen storage in metal-organic frameworks and porous carbon (United States)

    Beckner, Matthew; Dailly, Anne


    We investigated hydrogen storage in micro-porous adsorbents at ambient temperature and pressures up to 320 bar. We measured three benchmark adsorbents: two metal-organic frameworks, Cu3(1,3,5-benzenetricarboxylate)2 [Cu3(btc)2; HKUST-1] and Zn4O(1,3,5-benzenetribenzoate)2 [Zn4O(btb)2; MOF-177], and the activated carbon MSC-30. In this talk, we focus on adsorption enthalpy calculations using a single adsorption isotherm. We use the differential form of the Claussius-Clapeyron equation applied to the Dubinin-Astakhov adsorption model to calculate adsorption enthalpies. Calculation of the adsorption enthalpy in this way gives a temperature independent enthalpy of 5-7 kJ/mol at the lowest coverage for the three materials investigated. Additionally, we discuss the assumptions and corrections that must be made when calculating adsorption isotherms at high-pressure and adsorption enthalpies.

  14. An Explosive Range Model Based on the Gas Composition, Temperature, and Pressure during Air Drilling

    Directory of Open Access Journals (Sweden)

    Xiangyu Fan


    Full Text Available Air drilling is low cost and effectively improves the penetration rate and causes minimal damage to liquid-sensitive pay zones. However, there is a potential downhole explosion when combustible gas mixed with drilling fluid reaches the combustible condition. In this paper, based on the underground combustion mechanism, an explosive range calculation model is established. This model couples the state equation and the empirical formula method, which considers the inert gas content, pressure, mixed gas component, and temperature. The result shows that increase of the inert gas content narrows the explosive range, while increase of the gas temperature and pressure improves the explosive range. A case in Chongqing, China, is used to validate the explosive range calculation model.

  15. The influence of temperature, pH, and water immersion on the high hydrostatic pressure inactivation of GI.1 and GII.4 human noroviruses. (United States)

    Li, Xinhui; Chen, Haiqiang; Kingsley, David H


    Detection of human norovirus (HuNoV) usually relies on molecular biology techniques, such as qRT-PCR. Since histo-blood group antigens (HBGAs) are the functional receptors for HuNoV, HuNoV can bind to porcine gastric mucin (PGM), which contains HBGA-like antigens. In this study, PGM-conjugated magnetic beads were used to collect and quantify potentially infectious HuNoV strains GI.1 and GII.4 treated by high hydrostatic pressure (HHP). Both GI.1 and GII.4 strains used in this study showed increasing pressure sensitivity as judged by loss of PGM binding with decreasing temperature over a range of 1 to 35 °C. Both GI.1 and GII.4 were more resistant to pressure at pH4 than at neutral pH. Because GI.1 was significantly more resistant to pressure than GII.4, it was used to evaluate HuNoV pressure inactivation in blueberries. GI.1 on dry blueberries was very resistant to pressure while immersion of blueberries in water during pressure treatments substantially enhanced the inactivation. For example, a 2 min-600 MPa treatment of dry blueberries at 1 and 21 °C resulted in pressure processing parameters (pressure, temperature, and time) and product formulations (such as pH) to inactivate HuNoV in high-risk foods such as berries. © 2013.

  16. Mantle dynamics with pressure- and temperature-dependent thermal expansivity and conductivity (United States)

    Tosi, Nicola; Yuen, David A.; de Koker, Nico; Wentzcovitch, Renata M.


    In numerical simulations of mantle convection it is commonly assumed that the coefficients of thermal expansion α and thermal conduction k are either constant or pressure-dependent. Pressure changes are generally computed using parametrizations that rely on extrapolations of low-pressure data for a single upper-mantle phase. Here we collect data for both the pressure and temperature dependence of α from a database of first-principles calculations, and of k from recent experimental studies. We use these data-sets to construct analytical parametrizations of α and k for the major upper- and lower-mantle phases that can be easily incorporated into exisiting convection codes. We then analyze the impact of such parametrizations on Earth's mantle dynamics by employing two-dimensional numerical models of thermal convection. When α is the only variable parameter, both its temperature and pressure dependence enhance hot plumes and tend to inhibit the descent of cold downwellings. Taking into account a variable k leads to a strong increase of the bulk mantle temperature, which reduces the buoyancy available to amplify bottom boundary layer instabilities and causes mantle flow to be driven primarily by the instability of cold plates whose surface velocity also tends to rise. When both parameters are considered together, we observe an increased propensity to local layering which favors slab stagnation in the transition zone and subsequent thickening in the lower mantle. Furthermore, the values of k near the core-mantle boundary ultimately control the effect of this physical property on convection, which stresses the importance of determining the thermal conductivity of the post-perovskite phase.

  17. Development of Aerosol Measurement, Sampling and Generation Experimental Facilities under High Temperature and High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Yong [FNC TECH., Yongin (Korea, Republic of)


    The pressure is key factor determining Knudsen number and it affects aerosol dynamics. Hence, it is important to design experimental facilities to simulate the aerosols transport phenomena and removal mechanisms in the high temperature and high pressure (HT/HP). In case of Nuclear Power Plant, during the Light Water Reactor (LWR) severe accident, core degradation results in the release of both vapors and aerosol particles which differ in composition depending on their source terms. Vapor and aerosols generated under severe accident enter the containment atmosphere and are distributed in the containment by atmospheric flow. Temperature and pressure in the containment increase until containment spray system, fan cooler system or FCVS initiates to extract heat and avoid pressurization. The main purpose of the experimental facility is to develop not only multi-purpose test loops applying for aerosol industry but also to evaluation performance of engineered safety system including containment filtered venting system. The main experiment will be carried out in this loop and provide representative behavior of the aerosols under HT/HP conditions. The aim of the research is to be able to 1) develop the aerosol generation, mixing, sampling and measurement system and conduct tests based on various aerosol concentration, thermal-hydraulic conditions including high temperature and pressure and type of carrier gases (air, nitrogen and steam), applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant, and 2) investigate aerosol behaviors and removal mechanisms under these conditions. The tests with the main carrier gas of air will be performed on PHASEⅠ, steam will be conducted on PHASEⅡ.


    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, E A; Tan, N; Koerner, J; Lorenz, K T; Maienschein, J L


    The pressure dependent deflagration rates of LLM-105 and TATB based formulations were measured in the LLNL high pressure strand burner. The role of binder amount, explosive type, and thermal damage and their effects on the deflagration rate will be discussed. Two different formulations of LLM-105 and three formulations of TATB were studied and results indicate that binder amount and type play a minor role in the deflagration behavior. This is in sharp contrast to the HMX based formulations which strongly depend on binder amount and type. The effect of preheating these samples was considerably more dramatic. In the case of LLM-105, preheating the sample appears to have little effect on the deflagration rate. In contrast, preheating TATB formulations causes the deflagration rate to accelerate and become erratic. The thermal and mechanical properties of these formulations will be discussed in the context of their pressure and temperature dependent deflagration rates.

  19. Electrical resistance measurement in lithium under high pressure and low temperature

    CERN Document Server

    Shimizu, K; Amaya, K


    Lithium is known as a 'simple metal' and the lightest alkaline metal in the periodic table. At ambient pressure lithium forms a body-centred-cubic structure and the conduction electrons are considered to be almost free from interaction with the atomic core. However, Neaton and Ashcroft (Neaton J B and Ashcroft N W 1999 Nature 400 141) predicted that dense lithium at around 100 GPa will be found to transform to a low-symmetry phase and show a semi-metallic behaviour, in their calculation. Recently Hanfland et al (Hanfland M, Syassen K, Christensen N E and Novikov D L 2000 Nature 408 174) reported the experimental behaviour of the existence of new high-pressure phase of lithium above 40 GPa which tends towards symmetry-breaking transitions. Here we report electrical resistance measurements on lithium performed at pressures up to 35 GPa at the temperature of 80 K.

  20. Electrical resistance measurement in lithium under high pressure and low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, K [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Ishikawa, H [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Amaya, K [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)


    Lithium is known as a 'simple metal' and the lightest alkaline metal in the periodic table. At ambient pressure lithium forms a body-centred-cubic structure and the conduction electrons are considered to be almost free from interaction with the atomic core. However, Neaton and Ashcroft (Neaton J B and Ashcroft N W 1999 Nature 400 141) predicted that dense lithium at around 100 GPa will be found to transform to a low-symmetry phase and show a semi-metallic behaviour, in their calculation. Recently Hanfland et al (Hanfland M, Syassen K, Christensen N E and Novikov D L 2000 Nature 408 174) reported the experimental behaviour of the existence of new high-pressure phase of lithium above 40 GPa which tends towards symmetry-breaking transitions. Here we report electrical resistance measurements on lithium performed at pressures up to 35 GPa at the temperature of 80 K.