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Sample records for pressure range micro pa

  1. New apparatus for calibrations in the range of 2 kPa absolute pressure

    NASA Astrophysics Data System (ADS)

    Woo, S. Y.; Choi, I. M.

    2005-12-01

    Capacitance diaphragm gauges (CDGs) are precise electromechanical pressure sensors in which the displacement of a stretched thin metal diaphragm is detected by the measurement of a capacitance. These are very accurate gauges, and are frequently used as transfer gauges. To calibrate such accurate low-pressure gauges, precise mercury manometers have been used. However, complexity, concern about mercury vapour, and cost of mercury manometers have made it difficult to use these manometers in many industrial calibration laboratories. As a substitute, gas-operated piston gauges can be used for the calibration of such low-pressure gauges. However, the minimum pressure that is necessary to balance the tare weight, which generally corresponds to a pressure of several kilopascals, is a major obstacle. To reduce this minimum operating pressure, we adopted a variable bell-jar pressure method. To realize this method effectively, we developed a new mass-handling device that makes it possible to add or remove weights up to 200 g easily, with a resolution of 10 g, without breaking the vacuum during the calibration. This calibration system can be used to measure pressures from 100 Pa to 2 kPa in the absolute mode. In this paper, we also present the calibration results for two types of CDGs with full-scale ranges of 1330 Pa and 1000 Pa, respectively.

  2. EURAMET.M.P-S9: comparison in the negative gauge pressure range -950 to 0 hPa

    NASA Astrophysics Data System (ADS)

    Saxholm, S.; Otal, P.; AltintaS, A.; Bermanec, L. G.; Durgut, Y.; Hanrahan, R.; Kocas, I.; Lefkopoulos, A.; Pražák, D.; Sandu, I.; Åetina, J.; Spohr, I.; Steindl, D.; Tammik, K.; Testa, N.

    2016-01-01

    A comparison in the negative gauge pressure range was arranged in the period 2011 - 2012. A total of 14 laboratories participated in this comparison: BEV (Austria), CMI (Czech Republic), DANIAmet-FORCE (Denmark), EIM (Greece), HMI/FSB-LPM (Croatia), INM (Romania), IPQ (Portugal), LNE (France), MCCAA (Malta), METROSERT (Estonia), MIKES (Finland), MIRS/IMT/LMT (Slovenia), NSAI (Ireland) and UME (Turkey). The project was divided into two loops: Loop1, piloted by MIKES, and Loop2, piloted by LNE. The results of the two loops are reported separately: Loop1 results are presented in this paper. The transfer standard was Beamex MC5 no. 25516865 with internal pressure module INT1C, resolution 0.01 hPa. The nominal pressure range of the INT1C is -1000 hPa to +1000 hPa. The nominal pressure points for the comparison were 0 hPa, -200 hPa, -400 hPa, -600 hPa, -800 hPa and -950 hPa. The reference values and their uncertainties as well as the difference uncertainty between the laboratory results and the reference values were determined from the measurement data by Monte Carlo simulations. Stability uncertainty of the transfer standard was included in the final difference uncertainty. Degrees of equivalences and mutual equivalences between the laboratories were calculated. Each laboratory reported results for all twelve measurement points, which means that there were 168 reported values in total. Some 163 of the 168 values (97 %) agree with the reference values within the expanded uncertainties, with a coverage factor k = 2. Among the laboratories, four different methods were used to determine negative gauge pressure. It is concluded that special attention must be paid to the measurements and methods when measuring negative gauge pressures. There might be a need for a technical guide or a workshop that provides information about details and practices related to the measurements of negative gauge pressure, as well as differences between the different methods. The comparison is

  3. Final report on EURAMET.M.P-S12 — Bilateral supplementary comparison of the national pressure standards of CMI and INRIM in the range 300 Pa to 15 kPa of negative gauge pressure

    NASA Astrophysics Data System (ADS)

    Krajícek, Zdenek; Bergoglio, Mercede; Pražák, Dominik; Pasqualin, Stefano

    2014-01-01

    This report describes a EURAMET bilateral supplementary comparison between Czech CMI and Italian INRIM in low negative gauge pressure in gas (nitrogen), denoted as EURAMET.M.P-S12. The digital non-rotating pressure balance FPG8601 manufactured by Fluke/DH-Instruments, USA is normally used for gauge and absolute pressures in the range from 1 Pa to 15 kPa, but with some modifications it can be used also for the negative gauge pressures in the same range. During the preparation of the visit of INRIM at CMI for the last comparison within the framework of EURAMET.M.P-K4.2010, it was agreed to also perform an additional comparison in the range from 300 Pa to 15 kPa of negative gauge pressure. The measurements were performed in October 2012. Both institutes successfully proved their equivalence in all the tested points in the range from 300 Pa to 15 kPa of negative gauge pressure in a comparison that had, so far, been unique. . Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  4. Intercomparison of Primary Manometers in the Range 30 kPa to 110 kPa: Pressure Balance at the LNE and Mercury Manometer at the VNIIFTRI

    NASA Astrophysics Data System (ADS)

    Astrov, D. N.; Guillemot, J.; Legras, J. C.; Zakharov, A. A.

    1994-01-01

    An intercomparison between the primary pressure balance of the LNE and a mercury manometer developed at the All-Russian Research Institute for Physical, Technical and Radio-Technical Measurements (VNIIFTRI) for purposes of temperature measurement was undertaken in 1990. A short description of the two standards is given. The transfer standard was a pressure balance equipped with a piston-cylinder assembly that has the same characteristics as the standard of the Laboratoire National d'Essais (LNE). The results obtained from 30 kPa to 110 kPa showed a systematic relative difference of 12 parts in 106 between the two standards. This difference is significant, as the combined relative uncertainty at 1 σ level is estimated to be 4,2 parts in 106. These results are analysed in this paper.

  5. Partial discharges and breakdown in SF6 in the pressure range 25-150 kPa in non-uniform background fields

    NASA Astrophysics Data System (ADS)

    Seeger, M.; Clemen, M.

    2014-01-01

    The partial discharge (PD) and electric breakdown mechanisms in SF6 at a plug contact in the pressure range 25-150 kPa were investigated at ambient temperature in a plug-plate arrangement. This parameter range has similar particle number densities as in the previous investigation of the dielectric recovery in a high-voltage circuit breaker (Seeger et al 2012 J. Phys. D: Appl. Phys. 45 395204), where optical access was limited and the relevant parameters of pressure and temperature could only be determined indirectly by computational fluid dynamic simulations. The present investigation did not have these limitations, since the pressure and temperature were well defined. Optical observation by an image intensified high speed camera in combination with a photo multiplier tube allowed an understanding of the various mechanisms for the PDs and breakdown to be gained. The breakdown fields and PD parameters could be well described by a simple leader model in the pressure range 75-150 kPa for negative polarity and above 25 kPa for positive polarity. Discrepancies with the model are observed below 75 kPa for negative polarity and at 25 kPa for positive polarity. This could be explained by a slow, repetitive heating mechanism which has not been reported so far.

  6. Final report on EURAMET.M.P-K4.2010: Key and supplementary comparison of national pressure standards in the range 1 Pa to 15 kPa of absolute and gauge pressure

    NASA Astrophysics Data System (ADS)

    Krajíček, Zdeněk; Bergoglio, Mercede; Jousten, Karl; Otal, Pierre; Sabuga, Wladimir; Saxholm, Sari; Pražák, Dominik; Vičar, Martin

    2014-01-01

    This report describes a EURAMET comparison of five European National Metrology Institutes in low gauge and absolute pressure in gas (nitrogen), denoted as EURAMET.M.P-K4.2010. Its main intention is to state equivalence of the pressure standards, in particular those based on the technology of force-balanced piston gauges such as e.g. FRS by Furness Controls, UK and FPG8601 by DHI-Fluke, USA. It covers the range from 1 Pa to 15 kPa, both gauge and absolute. The comparison in absolute mode serves as a EURAMET Key Comparison which can be linked to CCM.P-K4 and CCM.P-K2 via PTB. The comparison in gauge mode is a supplementary comparison. The comparison was carried out from September 2008 till October 2012. The participating laboratories were the following: CMI, INRIM, LNE, MIKES, PTB-Berlin (absolute pressure 1 kPa and below) and PTB-Braunschweig (absolute pressure 1 kPa and above and gauge pressure). CMI was the pilot laboratory and provided a transfer standard for the comparison. This transfer standard was also the laboratory standard of CMI at the same time, which resulted in a unique and logistically difficult star comparison. Both in gauge and absolute pressures all the participating institutes successfully proved their equivalence with respect to the reference value and all also proved mutual bilateral equivalences in all the points. All the participating laboratories are also equivalent with the reference values of CCM.P-K4 and CCM.P-K2 in the relevant points. The comparison also proved the ability of FPG8601 to serve as a transfer standard. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  7. EURAMET.M.P-S9 / EURAMET 1170, LOOP2. Comparison in the negative gauge pressure range -950 to 0 hPa

    NASA Astrophysics Data System (ADS)

    Otal, P.; Boineau, F.; Medina, N.; Pražák, D.; Wüthrich, C.; Saxholm, S.; Sabuga, W.; Kocas, I.; Durgut, Y.

    2017-01-01

    This report gives the results of a comparison of pressure standards of seven European National Metrology institutes in the range of negative gauge pressure from -950 hPa to 0 hPa. This comparison was piloted by LNE and was carried out from January 2011 to March 2012. This work is a part of the EURAMET project 1170 and is registered as a supplementary comparison EURAMET.M.P-S9. The transfer standard used was a pressure monitor RPM4 A160Ks manufactured by DH Instruments Inc., with a resolution of 0.1 Pa. The reference values have been determined from the weighted mean of the deviations reported by the participants for each specified pressure. Seventy-three of the seventy-seven values (96%) reported by the laboratories agree with the reference values within the expanded uncertainties with a coverage factor k = 2. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  8. Final report on APMP.M.P-S4: Results of the bilateral supplementary comparison on pressure measurements in the range (60 to 350) kPa of gauge pressure in gas media

    NASA Astrophysics Data System (ADS)

    Priruenrom, T.; Sabuga, W.; Konczak, T.

    2013-01-01

    The bilateral supplementary comparison APMP.M.P-S4 on pressure measurements in the range (60 to 350) kPa of gauge pressure in gas media was organized by National Institute of Metrology of Thailand, NIMT, as the pilot laboratory, comparing with Physikalisch-Technische Bundesanstalt of Germany, PTB. The objective of this comparison is to check equivalence of gas pressure standards between NIMT and PTB. The period of measurement covered November to December 2012. NIMT provided a transfer standard, which was a WC-WC piston-cylinder assembly (PCA) with a nominal effective area of 10 cm2 manufactured by Fluke Corporation, DHI. The measurements were performed at pressures (60, 100, 150, 200, 250, 300 and 350) kPa. The NIMT laboratory standard used was a pressure balance with a PCA of 10 cm2 manufactured by DHI and identified by serial number 0693. The PTB laboratory standard used was a pressure balance with a PCA of 10 cm2 manufactured by Desgranges et Huot (DH) and identified by serial number 288. The results of this comparison show that the relative difference of the effective area values obtained by NIMT and PTB is not larger than 4.3 ppm, which corresponds to En = 0.26. Therefore, it confirms that the gas pressure standards maintained by the two institutes, NIMT and PTB, in the pressure range (60 to 350) kPa in gauge mode are equivalent under their uncertainties claimed. The result of this comparison is essential to support the calibration and measurement capabilities (CMC) of NIMT in this pressure range. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the APMP, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  9. Final report on the key comparison, CCM.P-K15 in the pressure range from 1.0 × 10(-4) Pa to 1.0 Pa.

    PubMed

    Wuethrich, Christian; Arai, Kenta; Bergoglio, Mercede; Fedchak, James A; Jousten, Karl; Hong, Seung Soo; Guzman, Jorge Torres

    2017-01-01

    The comparison CCM.P-K15 is a key comparison in pressure involving six laboratories in three regional metrological organizations (RMO). The measurand of the comparison is the accommodation coefficient of two spinning rotating gauge characterized in nitrogen from 0.1 mPa up to 1.0 Pa. The two transfer standards were circulated from November 2009 until March 2011. The circulation consisted of three loops, one for each RMO, and a new calibration by the pilot between each loop. The stability of one of the transfer standards was poor and was worse than expected based on the previous history of the transfer standard while the other transfer standard demonstrated good stability while circulated in Europe and America and a fair stability while circulated in Asia. All the participants demonstrated equivalence to the definition of pressure in their respective primary standards.

  10. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 105 Pa

    PubMed Central

    Berg, Robert F.

    2016-01-01

    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 105 Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures are presented for naphthalene, ferrocene, diethyl phthalate, and TEMAH (tetrakisethylmethylaminohafnium). Also presented are data for the temperature-dependent decomposition rate of TEMAH. PMID:27274567

  11. Final report on the key comparison, CCM.P-K15 in the pressure range from 1.0 × 10-4 Pa to 1.0 Pa

    NASA Astrophysics Data System (ADS)

    Wuethrich, Christian; Arai, Kenta; Bergoglio, Mercede; Fedchak, James A.; Jousten, Karl; Hong, Seung Soo; Torres Guzman, Jorge

    2017-01-01

    The comparison CCM.P-K15 is a key comparison in pressure involving six laboratories in three regional metrological organizations (RMO). The measurand of the comparison is the accommodation coefficient of two spinning rotating gauge characterized in nitrogen from 0.1 mPa up to 1.0 Pa. The two transfer standards were circulated from November 2009 until March 2011. The circulation consisted of three loops, one for each RMO, and a new calibration by the pilot be-tween each loop. The stability of one of the transfer standards was poor and was worse than expected based on the previous history of the transfer standard while the other transfer standard demonstrated good stability while circulated in Europe and America and a fair stability while circulated in Asia. All the participants demonstrated equivalence to the definition of pressure in their respective primary standards. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Final report on the supplementary comparison, EURAMET.M.P-S7 (EURAMET project 1040) in the pressure range from 1.10-4 Pa to 0.9 Pa

    NASA Astrophysics Data System (ADS)

    Wüthrich, C.; Alisic, S.; Bergoglio, M.; Saxholm, S.; Lefkopoulos, A.; Pražák, D.; Setina, J.

    2016-01-01

    Many laboratories within EURAMET started a calibration service in medium and high vacuum recently and did not have the opportunity to take part to a comparison before. In order to assess the uncertainty budget and the quality of the measurement of these laboratories, an intercomparison, EURAMET 1040 registered as EURAMET.M.P-S7, from 0.1 mPa to 0.9 Pa has been organised. The participants are the CMI (Czech republic), EIM (Greece), IMT (Slovenia), INRIM (Italy), IMBIH (Bosnia Herzegovinia) and MIKES (Finland) while METAS (Switzerland) is pilot laboratory. Three laboratories (INRIM, CMI and METAS) involved in this work have a primary definition of the pressure. Two spinning rotor gauges and a control electronic are used as transfer standard. The circulation of the transfer standard is organised as a succession of loops with a measurement by the pilot between each participant. A reference value has been determined based on a weighted mean of the results of the primary laboratories. All the participants have demonstrated their equivalence in the definition of the pressure. This comparison has been used as pilot comparison for the CCM.P-K14 project which covers the same scope with similar transfer standards. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  13. Wide-pressure-range coplanar dielectric barrier discharge: Operational characterisation of a versatile plasma source

    NASA Astrophysics Data System (ADS)

    Čech, J.; Bonaventura, Z.; SÅ¥ahel, P.; Zemánek, M.; Dvořáková, H.; Černák, M.

    2017-01-01

    Many plasma applications could benefit from the versatile plasma source operable at a wide-pressure-range, e.g., from the fraction of Pa to the super-atmospheric conditions. In this paper, the basic characteristics of wide-pressure-range plasma source based on the coplanar dielectric barrier discharge is given. The operational characteristics of this plasma source were measured in nitrogen at pressures ranging from 101 Pa (resp. 10-4 Pa) to 105 Pa. Measurements of the plasma geometry, breakdown voltage, and micro-discharges' behaviour revealed three operational regimes of this plasma source: "high pressure," "transitional" and "low-pressure" with vague boundaries at the pressures of approx. 10 kPa and 1 kPa. It was found that the plasma layer of coplanar dielectric barrier discharge could be expanded up to several centimetres to the half-space above the planar dielectric barrier when the gas pressure is reduced below 1 kPa, which provides an outstanding space to tailor the source for the specific applications. The proposed model of an effective gap distance in the Paschen breakdown criterion enabled us to explain the discharge behaviour fitting the experimental breakdown voltage data in the whole studied pressure range. Under the filament-forming conditions, i.e., at the pressure range from approx. 1-100 kPa, the active plasma volume could be varied through the micro-discharges' lateral thickness scaling with the inverse of the square-root of the gas pressure.

  14. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 10(5) Pa.

    PubMed

    Berg, Robert F

    2015-11-01

    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 10(5) Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures are presented for naphthalene, ferrocene, diethyl phthalate, and TEMAH (tetrakisethylmethylaminohafnium). Also presented are data for the temperature-dependent decomposition rate of TEMAH.

  15. Range and railgun development results at LS and PA ``Soyuz``

    SciTech Connect

    Babakov, Y.P.; Plekhanov, A.V.; Zheleznyi, V.B.

    1995-01-01

    A rail electromagnetic accelerator is one of the most reliable and simple devices for accelerating macroparticles up to high velocity. These accelerators allow scientists to carry out fundamental and applied investigations to study both equation-of-state of materials at high pressure due to high velocity encounters, and creation of conditions for shock thermonuclear fusion. In the department ``Energophyzika`` LS and PA ``Soyuz`` range was created. It was equipped with an inductor with storage capacity up to 12.5 MJ energized by a solid propellant MHD generator and a capacitor bank (energy capacity up to 6 MJ). These systems deliver currents of 1 MA and 2 MA, respectively. Diagnostic, recording, and autocalculation systems allow use of as many as 120 data channels with acquisition frequency up to 10 MHz. Recent technical successes in railgun construction, using special methods to compact plasma armature and produce high velocity trailing contact, creation of hybrid armatures, and optimizing acceleration made possible to gain velocities in the range of 6.2 to 6.8 km/s (masses of 3.8 to 10 g) and velocities 2.7 to 3.8 km/s (masses of 50 to 100 g) on railguns with length 2 to 4 m.

  16. Aqueous solubility (in the range between 298.15 and 338.15 K), vapor pressures (in the range between 10(-5) and 80 Pa) and Henry's law constant of 1,2,3,4-dibenzanthracene and 1,2,5,6-dibenzanthracene.

    PubMed

    Abou-Naccoul, Ramy; Mokbel, Ilham; Bassil, Georgio; Saab, Joseph; Stephan, Khaled; Jose, Jacques

    2014-01-01

    Aqueous solubility and vapor pressures of 1,2,3,4-dibenzanthracene and 1,2,5,6-dibenzanthracene were determined using dynamic saturation methods. For the two isomers, aqueous solubility is in the range between 10(-10) and 10(-2) in molar fraction corresponding to temperature between 298.15 and 338.15K. Vapor pressures of the pure solutes range from 10(-5) to 80 Pa. Prior to the study of the two dibenzanthracenes and in order to check the experimental procedures, solubility of fluoranthene (between 298 and 338 K) and vapor pressures of phenanthrene and fluoranthene (between 300 and 470 K) were measured. From aqueous solubility data coupled with the vapor pressures of the pure solutes, partition coefficient air-water, KAW, and Henry's constant, KH, of environmental relevance were calculated.

  17. Micro-Laser Range Finder Development: Using the Monolithic Approach

    DTIC Science & Technology

    1999-02-01

    Approved for public release; distribution is unlimited. Micro- Laser Range Finder Development: Using the Monolithic Approach February 1999 John... Nettleton , Dallas Barr, Brad Schilling & Jonathan Lei US ARMY CECOM RDEC NVESD Fort Belvoir, VA Samuel M. Goldwasser Engineering Consultant Bala-Cynwyd, PA...ABSTRACT Laser range finders are a vital component of high precision targeting engagements. The precise and accurate range-to-target information is

  18. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    NASA Astrophysics Data System (ADS)

    Xiong, Liu; Yan, Yao; Jiahao, Ma; Yanhang, Zhang; Qian, Wang; Zhaohua, Zhang; Tianling, Ren

    2015-06-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm2. It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm2. In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm2. Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10-2 mV/kPa. Project supported by the National Natural Science Foundation of China (Nos. 61025021, 61434001), and the ‘Thousands Talents’ Program for Pioneer Researchers and Its Innovation Team, China.

  19. High range resolution micro-Doppler analysis

    NASA Astrophysics Data System (ADS)

    Cammenga, Zachary A.; Smith, Graeme E.; Baker, Christopher J.

    2015-05-01

    This paper addresses use of the micro-Doppler effect and the use of high range-resolution profiles to observe complex targets in complex target scenes. The combination of micro-Doppler and high range-resolution provides the ability to separate the motion of complex targets from one another. This ability leads to the differentiation of targets based on their micro-Doppler signatures. Without the high-range resolution, this would not be possible because the individual signatures would not be separable. This paper also addresses the use of the micro-Doppler information and high range-resolution profiles to generate an approximation of the scattering properties of a complex target. This approximation gives insight into the structure of the complex target and, critically, is created without using a pre-determined target model.

  20. Bilateral key comparison CCM.P-K3.1 for absolute pressure measurements from 3 × 10-6 Pa to 9 × 10-4 Pa

    NASA Astrophysics Data System (ADS)

    Fedchak, J. A.; Bock, Th; Jousten, K.

    2014-01-01

    This report describes the bilateral key comparison CCM.P-K3.1 between the National Institute of Standards and Technology (NIST) and Physikalisch-Technische Bundesanstalt (PTB) for absolute pressure in the range from 3 × 10-6 Pa to 9 × 10-4 Pa. This comparison was a follow-up to the comparison CCM.P-K3. Two ionization gauges and two spinning rotor gauges (SRGs) were used as the transfer standards for the comparison. The SRGs were used to compare the standards at a pressure of 9 × 10-4 Pa and to normalize the ionization gauge readings. The two ionization gauges were used to compare the standards in the pressure range of from 3 × 10-6 Pa to 3 × 10-4 Pa. Both laboratories used dynamic expansion chambers as standards in the comparison. The two labs showed excellent agreement with each other and with the CCM.P-K3 key comparison reference value (KCRV) over the entire range. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  1. Micro-range micro-doppler for dismount classification

    NASA Astrophysics Data System (ADS)

    Tahmoush, Dave

    2013-05-01

    This paper presents a processing technique that can be used to detect and classify pedestrians group based on the micro- Doppler signature gathered with a millimeter wave radar. The evaluation of the number of pedestrians moving in a group can be a difficult task using a traditional micro-Doppler spectrogram because of a tendency for people to partially synchronize their steps when walking together. The new approach, based on multi-range variation as well as the micro-Doppler variations, provides promising results. The range-spectrogram processing technique was developed and tested using a database composed of hundreds of pedestrian and vehicle signatures gathered in an urban test site over a two year period in a variety of weather conditions. We associate image detections with radar detections through motion extracted from both radar and imagery. We also explain how radar and video together can produce an inexpensive alternative to 3-D imaging.

  2. Comparison in gas media (absolute and gauge mode)in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

    NASA Astrophysics Data System (ADS)

    Wuethrich, C.; Alisic, S.; Altintas, A.; van Andel, I.; C, In­Mook; Eltawil, A. A.; Farár, P.; Hetherington, P.; Koçaş, I.; Lefkopoulos, A.; Otal, P.; Prazak, D.; Sabuga, W.; Salustiano, R.; Sandu, I.; Sardi, M.; Saxholm, S.; Setina, J.; Spohr, I.; Steindl, D.; Testa, N.; Vámossy, C.; Grgec Bermanec, L.

    2016-01-01

    It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow a link to the CCM.P-K6 and CCM.P-K2 comparisons to be established. This project interested a lot of laboratories from the beginning with 23 participants, 22 of which have submitted results. The circulation of the transfer standard began in July 2009 and lasted until January 2012. No major problems occurred during the transport. The measurand of the comparison is the effective area of a piston-cylinder determined in gauge and absolute pressure from 25 kPa to 200 kPa with pressure steps of 25 kPa. The transfer standard is a gas lubricated tungsten carbide piston-cylinder with an effective area of ~9.8 cm2, fabricated by DH Instruments and compatible with a PG-7601 pressure balance. Some participants used their own pressure balance while a pressure balance with a reference vacuum sensor has been circulated for the participants not equipped with this system. One participant (SMU, Slovakia) has never provided the measurement results and another participant (FORCE Technology, Denmark) submitted a revised set of measurement results after the pilot laboratory mentioned that the equivalence was not met. After the determination of the reference value, all the 22 participants who delivered the results in gauge pressure demonstrated equivalence respective to the reference value on most of the range. In absolute pressure the equivalence is demonstrated, for all nominal pressures, by all 17 participants who submitted results. The comparison is linked to the CCM.P-K6 for gauge pressure and to CCM.P-K2 for absolute pressure. The link does not strongly affect the equivalence of the results and an excellent degree of equivalence is achieved in gauge and absolute pressure. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb

  3. Posterior-anterior(PA) pressure Puffin for measuring and treating spinal stiffness: Mechanism and repeatability.

    PubMed

    Björnsdóttir, Sigrún Vala; Guðmundsson, Geir; Auðunsson, Guðjón Atli; Matthíasson, Jón; Ragnarsdóttir, María

    2016-04-01

    Posterior-anterior (PA) pressure technique is widely used for assessing and treating spinal segments. PA pressure is manually applied and stiffness is subjectively assessed. The method has been deemed unreliable and is associated with occupational strain. To introduce a new ergonomically designed hand-held device measuring spinal stiffness, and to assess its repeatability. Quasi experimental study. A convenience sample of 30 university students, 20-30 years old was used. The participants were tested two consecutive days by two physical therapy students using the new device; the PA pressure Puffin. The spinal segments under study were L1, Th12, Th7 and Th6 which all were tested three times with 9 kg force by both testers, both days. Intra-class correlation coefficients (ICC3,k) were used to assess intra- and inter-tester repeatability and analysis of variance with alpha-level at 0.05 was used to assess differences in joint mobility at the four segments measured. Linear regression analyses were used to assess repeatability. Inter-tester and intra-tester coefficients (ICCs) ranged from 0.88 to 0.97 and from 0.83 to 0.97, respectively. There was no significant difference in displacement between Th6 and Th7 but all other joints were significantly different from each other. Displacement was always significantly greater the second day compared with day one (p < 0.05). This close to final prototype of the PA pressure Puffin measures segmental spinal stiffness and its ergonomically designed handle provides a promising tool for physical therapists applying PA pressure. Further research is needed for validation and reliability assessments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Development of Pressure Sensitive Molecular Film as a Measurement Technique for Micro-Flows

    NASA Astrophysics Data System (ADS)

    Matsuda, Y.; Mori, H.; Sakazaki, Y.; Uchida, T.; Suzuki, S.; Yamaguchi, H.; Niimi, T.

    2008-12-01

    The pressure-sensitive paint (PSP) has potential as a diagnostic tool for pressure measurement in the high Knudsen number regime because it works as a so-called "molecular sensor." However, there are few reports concerning application of the PSP to micro devices, because the conventional PSP is too thick owing to the use of polymer binder. In our previous work, we have adopted Langmuir-Blodgett (LB) technique to fabricate pressure sensitive molecular films (PSMFs) using Pd(II) Mesoporphyrin IX (PdMP). The PSMF based on PdMP has pressure sensitivity only at low pressure range (below 3 kPa). In this study, we have constructed PSMF composed of Pt(II) Mesoporphyrin IX (PtMP) to be applied to pressure measurement near atmospheric pressure. The pressure sensitivity of PSMF based on PtMP has been tested, and it is clarified that the PSMF of PtMP has equivalent pressure sensitivity of polymer PSP. Moreover, we have applied PSMF to measurement of pressure distribution of micro-channel gas flow, showing its usefulness.

  5. FOREWORD: The 4th CCM International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa)

    NASA Astrophysics Data System (ADS)

    Legras, Jean-Claude; Jousten, Karl; Severn, Ian

    2005-12-01

    The fourth CCM (Consultative Committee for Mass and related quantities) International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa) was held at the Institute of Physics in London from 19-21 April 2005. The event, which was organized by the Low, Medium and High Pressure working groups of the CCM, was attended by in excess of one hundred participants with representatives from five continents and every regional metrology organization. The purpose of this conference is to review all the work that is devoted to the highest quality of pressure measurement by primary standards as well as the dissemination of the pressure scale. A total of 52 papers were presented orally, and 26 as posters, in sessions that covered the following topics: Latest scientific advances in pressure and vacuum metrology Innovative transfer standards, advanced sensors and new instrument development Primary (top-level) measurement standards International and regional key comparisons New approaches to calibration It is interesting the note that since the third conference in 1999 the pressure range covered has increased by two orders of magnitude to 109 Pa, to take into account more exacting scientific and industrial demands for traceable vacuum measurement. A further feature of the conference was the increased range of instrumentation and techniques used in the realization and potential realization of pressure standards. Seton Bennett, Director of International Metrology at the National Physical Laboratory, opened the conference and Andrew Wallard, Director of the Bureau International des Poids et Mesures (BIPM), gave the keynote address which described the implementation of the mutual recognition arrangement and the resulting removal of metrological barriers to international trade. Many experts have contributed significant amounts of their time to organize the event and to review the submitted papers. Thanks are due to all of these people

  6. A Graphene-Based Resistive Pressure Sensor with Record-High Sensitivity in a Wide Pressure Range

    NASA Astrophysics Data System (ADS)

    Tian, He; Shu, Yi; Wang, Xue-Feng; Mohammad, Mohammad Ali; Bie, Zhi; Xie, Qian-Yi; Li, Cheng; Mi, Wen-Tian; Yang, Yi; Ren, Tian-Ling

    2015-02-01

    Pressure sensors are a key component in electronic skin (e-skin) sensing systems. Most reported resistive pressure sensors have a high sensitivity at low pressures (<5 kPa) to enable ultra-sensitive detection. However, the sensitivity drops significantly at high pressures (>5 kPa), which is inadequate for practical applications. For example, actions like a gentle touch and object manipulation have pressures below 10 kPa, and 10-100 kPa, respectively. Maintaining a high sensitivity in a wide pressure range is in great demand. Here, a flexible, wide range and ultra-sensitive resistive pressure sensor with a foam-like structure based on laser-scribed graphene (LSG) is demonstrated. Benefitting from the large spacing between graphene layers and the unique v-shaped microstructure of the LSG, the sensitivity of the pressure sensor is as high as 0.96 kPa-1 in a wide pressure range (0 ~ 50 kPa). Considering both sensitivity and pressure sensing range, the pressure sensor developed in this work is the best among all reported pressure sensors to date. A model of the LSG pressure sensor is also established, which agrees well with the experimental results. This work indicates that laser scribed flexible graphene pressure sensors could be widely used for artificial e-skin, medical-sensing, bio-sensing and many other areas.

  7. In Vitro and in vivo characterization of wireless and passive micro system enabling gastrointestinal pressure monitoring.

    PubMed

    Shi, Qiang; Wang, Junbo; Chen, Deyong; Chen, Jian; Li, Jing; Bao, Kaikai

    2014-12-01

    This paper presents a wireless and passive micro pressure system based on the LC mutual inductance detection mechanism for gastrointestinal (GI) pressure monitoring. The micro pressure system is composed of a sensor capsule (a pressure sensitive micro capacitive sensor in series with an induction coil to form an LC tank) and a detection unit (a detection coil connected with a network analyzer). The pressure variations under measurement lead to changes in the capacitance of the pressure sensor and therefore a shift in the LC tank resonant frequency, quantified by the impedance measurement of the detection coil. The pressure sensor was fabricated using microfabrication processes with key parameters optimized. The in vitro characterization of the micro pressure system recorded a sensitivity of 0.2491 kHz/kPa (-10 kPa to 30 kPa). One-month rabbit stomach pressure monitoring was conducted based on the developed micro pressure system as a confirmation of device long term in vivo stability. Furthermore, rabbit stomach pressure variations before and after food feeding was recorded and compared where three distinctive contraction patterns (random contraction with low amplitude, irregular strong contractions and regular contraction in a cyclic manner) following food feeding were located. Compared to previous reported GI pressure sensors, this LC tank is featured with simple device structure without batteries and electrical components for energy transfer. Both in vitro and in vivo characterization confirm the functionality of the system, which may enable the gastrointestinal motility study in the near future.

  8. Incorporation of beams into bossed diaphragm for a high sensitivity and overload micro pressure sensor.

    PubMed

    Yu, Zhongliang; Zhao, Yulong; Sun, Lu; Tian, Bian; Jiang, Zhuangde

    2013-01-01

    The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 μV/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa.

  9. A Graphene-Based Resistive Pressure Sensor with Record-High Sensitivity in a Wide Pressure Range

    PubMed Central

    Tian, He; Shu, Yi; Wang, Xue-Feng; Mohammad, Mohammad Ali; Bie, Zhi; Xie, Qian-Yi; Li, Cheng; Mi, Wen-Tian; Yang, Yi; Ren, Tian-Ling

    2015-01-01

    Pressure sensors are a key component in electronic skin (e-skin) sensing systems. Most reported resistive pressure sensors have a high sensitivity at low pressures (<5 kPa) to enable ultra-sensitive detection. However, the sensitivity drops significantly at high pressures (>5 kPa), which is inadequate for practical applications. For example, actions like a gentle touch and object manipulation have pressures below 10 kPa, and 10–100 kPa, respectively. Maintaining a high sensitivity in a wide pressure range is in great demand. Here, a flexible, wide range and ultra-sensitive resistive pressure sensor with a foam-like structure based on laser-scribed graphene (LSG) is demonstrated. Benefitting from the large spacing between graphene layers and the unique v-shaped microstructure of the LSG, the sensitivity of the pressure sensor is as high as 0.96 kPa−1 in a wide pressure range (0 ~ 50 kPa). Considering both sensitivity and pressure sensing range, the pressure sensor developed in this work is the best among all reported pressure sensors to date. A model of the LSG pressure sensor is also established, which agrees well with the experimental results. This work indicates that laser scribed flexible graphene pressure sensors could be widely used for artificial e-skin, medical-sensing, bio-sensing and many other areas. PMID:25721159

  10. The nanogap Pirani—a pressure sensor with superior linearity in an atmospheric pressure range

    NASA Astrophysics Data System (ADS)

    Khosraviani, Kourosh; Leung, Albert M.

    2009-04-01

    We have designed and fabricated a surface micromachined Pirani pressure sensor with an extremely narrow gap between its heater and heatsink (substrate) with superior output linearity in the atmospheric pressure range. The gap size of the device has been reduced to 50 nm by using a layer of PECVD amorphous silicon as a sacrificial layer and a xenon difluoride (XeF2) gas phase etching technique. Such a narrow gap pushes the transition from molecular to continuum heat conduction to pressures beyond 200 kPa. The higher transition pressure increases the measurement range and sensitivity of the gauge in atmospheric pressures. The gas phase etching of the sacrificial layer eliminates stiction problems related to a wet etching process. The active area of the sensor is only a 6 × 50 µm2 microbridge anchored to the substrate at both ends. An innovative fabrication technique was developed which resulted in a virtually flat microbridge with improved mechanical robustness. This process enabled us to have a very well-controlled gap between the microbridge and the substrate. The device was tested in a constant heater temperature mode with pressure ranges from 0.1 to 720 kPa. The heater power was only 3 mW at 101 kPa (atmospheric pressure), which increased to about 8 mW at 720 kPa. The output sensitivity and nonlinearity of the device were 0.55% per kPa at 101 kPa and ±13% of the output full scale, respectively.

  11. Final Report on the Key Comparison CCM.P-K4.2012 in Absolute Pressure from 1 Pa to 10 kPa.

    PubMed

    Ricker, Jacob; Hendricks, Jay; Bock, Thomas; Dominik, Pražák; Kobata, Tokihiko; Torres, Jorge; Sadkovskaya, Irina

    2017-01-01

    The report summarizes the Consultative Committee for Mass (CCM) key comparison CCM.P-K4.2012 for absolute pressure spanning the range of 1 Pa to 10 000 Pa. The comparison was carried out at six National Metrology Institutes (NMIs), including National Institute of Standards and Technology (NIST), Physikalisch-Technische Bundesanstalt (PTB), Czech Metrology Institute (CMI), National Metrology Institute of Japan (NMIJ), Centro Nacional de Metrología (CENAM), and DI Mendeleyev Institute for Metrology (VNIIM). The comparison was made via a calibrated transfer standard measured at each of the NMIs facilities using their laboratory standard during the period May 2012 to September 2013. The transfer package constructed for this comparison preformed as designed and provided a stable artifact to compare laboratory standards. Overall the participants were found to be statistically equivalent to the key comparison reference value.

  12. Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges

    NASA Astrophysics Data System (ADS)

    Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

    2017-03-01

    Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ~3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.

  13. Pressure-induced phase transitions in Pa metal from first-principles theory

    SciTech Connect

    Soederlind, P.; Eriksson, O.

    1997-11-01

    Protactinium metal is shown to undergo a phase transition to the {alpha}-U orthorhombic structure below 1 Mbar pressure. At higher pressures, the bct phase reenters in the phase diagram and at the highest pressures, an ideal hcp structure becomes stable. Hence, Pa undergoes a sequence of transitions; bct{r_arrow}{alpha}-U{r_arrow}bct{r_arrow}hcp, with the first transition taking place at 0.25 Mbar and the subsequent ones above 1 Mbar. The bct{r_arrow}{alpha}-U transition is triggered by the pressure-induced promotion of the spd valence states to 5f states. In this regard, Pa approaches uranium which at ambient conditions has one more 5f electron than Pa at similar conditions. At higher compression of Pa, the 5f band broadens and electrostatic interactions in combination with Born-Mayer repulsion become increasingly important and this drives Pa to gradually more close-packed structures. At ultrahigh pressures, the balance between electrostatic energy, Born-Mayer repulsion, and one-electron band energy stabilizes the hcp (ideal packing) structure. The electrostatic energy and Born-Mayer repulsion rule out open crystal structures under these conditions in Pa and between the close-packed structures, the hcp structure is shown to be stabilized by filling of the 5f band. {copyright} {ital 1997} {ital The American Physical Society}

  14. Pressure-induced phase transitions in Pa metal from first-principles theory

    NASA Astrophysics Data System (ADS)

    Söderlind, Per; Eriksson, Olle

    1997-11-01

    Protactinium metal is shown to undergo a phase transition to the α-U orthorhombic structure below 1 Mbar pressure. At higher pressures, the bct phase reenters in the phase diagram and at the highest pressures, an ideal hcp structure becomes stable. Hence, Pa undergoes a sequence of transitions; bct-->α-U-->bct-->hcp, with the first transition taking place at 0.25 Mbar and the subsequent ones above 1 Mbar. The bct-->α-U transition is triggered by the pressure-induced promotion of the spd valence states to 5f states. In this regard, Pa approaches uranium which at ambient conditions has one more 5f electron than Pa at similar conditions. At higher compression of Pa, the 5f band broadens and electrostatic interactions in combination with Born-Mayer repulsion become increasingly important and this drives Pa to gradually more close-packed structures. At ultrahigh pressures, the balance between electrostatic energy, Born-Mayer repulsion, and one-electron band energy stabilizes the hcp (ideal packing) structure. The electrostatic energy and Born-Mayer repulsion rule out open crystal structures under these conditions in Pa and between the close-packed structures, the hcp structure is shown to be stabilized by filling of the 5f band.

  15. FOREWORD: CCM Second International Seminar: Pressure Metrology from 1 kPa to 1 GPa

    NASA Astrophysics Data System (ADS)

    Molinar, G. F.

    1994-01-01

    The Comité Consultatif pour la Masse et les Grandeurs Apparentées (CCM), through its High Pressure and Medium Pressure Working Groups, organized this Second International Seminar on Pressure Metrology from 1 kPa to 1 GPa, which was held at the Laboratoire National d'Essais (LNE), Paris, France, from 2 to 4 June 1993. The scope of the seminar was to review the state of the art of pressure measurements in the 1 kPa to I GPa pressure range and to present innovative contributions by standards laboratories, universities and industry. The seminar was organized in six sessions: liquid-column manometers; piston gauge pressure standards; properties of liquids and gases relevant to pressure metrology; pressure transducers and transfer standards; pressure standard comparison (methods and results); dynamic pressure measurements. Each session opened with the presentation of a review paper on major requirements in that field and, at the end of the seminar, a general discussion was organized on the actual limits of accuracy of static and dynamic pressure measurements in fluid media, and the fundamental problems in pressure metrology between 1 kPa and 1 GPa. The seminar was attended by sixty scientists from twenty-four countries, all working in the field of pressure measurements. Forty-nine papers were presented. The participation of scientists from so many countries indicates the importance of pressure metrology from the scientific and industrial points of view. Most papers were presented by scientists from national standards laboratories, with eight papers from universities and four from industry. Eleven papers reported the results of cooperative work involving metrological institutions dealing with high pressure, generally national standards laboratories, an indication that scientific links are already well established at this level. Links are also strengthening between industry and standards laboratories. Although industrial participation at the seminar was relatively small

  16. Effect of oxygen breathing on micro oxygen bubbles in nitrogen-depleted rat adipose tissue at sea level and 25 kPa altitude exposures.

    PubMed

    Randsoe, Thomas; Hyldegaard, Ole

    2012-08-01

    The standard treatment of altitude decompression sickness (aDCS) caused by nitrogen bubble formation is oxygen breathing and recompression. However, micro air bubbles (containing 79% nitrogen), injected into adipose tissue, grow and stabilize at 25 kPa regardless of continued oxygen breathing and the tissue nitrogen pressure. To quantify the contribution of oxygen to bubble growth at altitude, micro oxygen bubbles (containing 0% nitrogen) were injected into the adipose tissue of rats depleted from nitrogen by means of preoxygenation (fraction of inspired oxygen = 1.0; 100%) and the bubbles studied at 101.3 kPa (sea level) or at 25 kPa altitude exposures during continued oxygen breathing. In keeping with previous observations and bubble kinetic models, we hypothesize that oxygen breathing may contribute to oxygen bubble growth at altitude. Anesthetized rats were exposed to 3 h of oxygen prebreathing at 101.3 kPa (sea level). Micro oxygen bubbles of 500-800 nl were then injected into the exposed abdominal adipose tissue. The oxygen bubbles were studied for up to 3.5 h during continued oxygen breathing at either 101.3 or 25 kPa ambient pressures. At 101.3 kPa, all bubbles shrank consistently until they disappeared from view at a net disappearance rate (0.02 mm(2) × min(-1)) significantly faster than for similar bubbles at 25 kPa altitude (0.01 mm(2) × min(-1)). At 25 kPa, most bubbles initially grew for 2-40 min, after which they shrank and disappeared. Four bubbles did not disappear while at 25 kPa. The results support bubble kinetic models based on Fick's first law of diffusion, Boyles law, and the oxygen window effect, predicting that oxygen contributes more to bubble volume and growth during hypobaric conditions. As the effect of oxygen increases, the lower the ambient pressure. The results indicate that recompression is instrumental in the treatment of aDCS.

  17. PaCO2 in surfactant, positive pressure, and oxygenation randomised trial (SUPPORT).

    PubMed

    Ambalavanan, Namasivayam; Carlo, Waldemar A; Wrage, Lisa A; Das, Abhik; Laughon, Matthew; Cotten, C Michael; Kennedy, Kathleen A; Laptook, Abbot R; Shankaran, Seetha; Walsh, Michele C; Higgins, Rosemary D

    2015-03-01

    To determine the association of arterial partial pressure of carbon dioxide PaCO2 with severe intraventricular haemorrhage (sIVH), bronchopulmonary dysplasia (BPD), and neurodevelopmental impairment (NDI) at 18-22 months in premature infants. Secondary exploratory data analysis of Surfactant, Positive Pressure, and Oxygenation Randomised Trial (SUPPORT). Multiple referral neonatal intensive care units. 1316 infants 24 0/7 to 27 6/7 weeks gestation randomised to different oxygenation (SpO2 target 85-89% vs 91-95%) and ventilation strategies. Blood gases from postnatal day 0 to day14 were analysed. Five PaCO2 variables were defined: minimum (Min), maximum (Max), SD, average (time-weighted), and a four level categorical variable (hypercapnic (highest quartile of Max PaCO2), hypocapnic (lowest quartile of Min PaCO2), fluctuators (hypercapnia and hypocapnia), and normocapnic (middle two quartiles of Max and Min PaCO2)). PaCO2 variables were compared for infants with and without sIVH, BPD and NDI (±death). Multivariable logistic regression models were developed for adjusted results. sIVH, BPD and NDI (±death) were associated with hypercapnic infants and fluctuators. Association of Max PaCO2 and outcomes persisted after adjustment (per 10 mm Hg increase: sIVH/death: OR 1.27 (1.13 to 1.41); BPD/death: OR 1.27 (1.12 to 1.44); NDI/death: OR 1.23 (1.10 to 1.38), death: OR 1.27 (1.12 to 1.44), all p<0.001). No interaction was found between PaCO2 category and SpO2 treatment group for sIVH/death, NDI/death or death. Max PaCO2 was positively correlated with maximum FiO2 (rs0.55, p<0.0001) and ventilator days (rs0.61, p<0.0001). Higher PaCO2 was an independent predictor of sIVH/death, BPD/death and NDI/death. Further trials are needed to evaluate optimal PaCO2 targets for high-risk infants. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. Wide Pressure Range Measurement due to the Exchange of Heater Driving of the Temperature Difference Sensor

    NASA Astrophysics Data System (ADS)

    Takashima, Noriaki; Kimura, Mitsuteru

    We have extended measurable pressure range of the thin film Pirani vacuum sensor that is still sensitive above 1×105 Pa (1 atmosphere). In our thin film Pirani vacuum sensor, our proposed temperature difference sensor of the short circuit Seebeck-current detection type thermocouple is used in order to get extremely high sensitivity, especially both in very low pressure range and in higher pressure range than 1×104 Pa. In our new pressure sensor the cantilever type sensing region, in which a microheater and two thermocouples are formed to measure the temperature difference, is adopted. Therefore, we can use the null method to measure very small pressure accurately in the high vacuum range (low pressure range). On the other hand in the higher pressure than 1×104 Pa., we could expand the pressure range by adoption of the vibration of the sensing cantilever based on the sudden heating due to the exchange of heater driving. We have achieved much wider measurable pressure range over 8 digits by use of our new simple thin film Pirani vacuum sensor than that of the traditional one.

  19. Final report on the key comparison CCM.P-K4.2012 in absolute pressure from 1 Pa to 10 kPa

    NASA Astrophysics Data System (ADS)

    Ricker, Jacob; Hendricks, Jay; Bock, Thomas; Dominik, Pražák; Kobata, Tokihiko; Torres, Jorge; Sadkovskaya, Irina

    2017-01-01

    The report summarizes the Consultative Committee for Mass (CCM) key comparison CCM.P-K4.2012 for absolute pressure spanning the range of 1 Pa to 10 000 Pa. The comparison was carried out at six National Metrology Institutes (NMIs), including National Institute of Standards and Technology (NIST), Physikalisch-Technische Bundesanstalt (PTB), Czech Metrology Institute (CMI), National Metrology Institute of Japan (NMIJ), Centro Nacional de Metrología (CENAM), and DI Mendeleyev Institute for Metrology (VNIIM). The comparison was made via a calibrated transfer standard measured at each of the NMIs facilities using their laboratory standard during the period May 2012 to September 2013. The transfer package constructed for this comparison preformed as designed and provided a stable artifact to compare laboratory standards. Overall the participants were found to be statistically equivalent to the key comparison reference value. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  20. Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

    2017-03-01

    In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

  1. IMI long-range surface plasmon Bragg micro-cavity

    NASA Astrophysics Data System (ADS)

    Tong, Kai; Wang, Jun; Zhou, Chunliang; Wang, Meiting

    2016-10-01

    The defect layer is introduced to the insulator-metal-insulator (IMI) Bragg waveguide structure. The micro-cavity structure of long-range surface plasma is proposed based on the defect mode. The liquid crystal is the defect layer in the structure of Bragg. The energy band characteristics of the long-range surface plasmon Bragg micro-cavity structure are analyzed by using the finite difference time domain method. The influence of the period number and the length of the micro-cavity on the quality factor Q and the volume V of the Bragg grating are discussed. The results show that the photonic energy can be confined very well in the micro-cavity by the structure of the micro-cavity. By controlling the birefringence of liquid crystal, the resonance wavelength of the micro-cavity appears with redshift phenomenon. The tuning range is 42 nm. The tuning of the working window of the long-range surface plasmon filter is realized. The photonic energy is the strongest in the insulating layer and the metal interface. The increase of cycles number has certain limitation on the improvement of the quality factor Q of the cavity. The influence of the defect-cavity length on the resonant wavelength, the quality factor Q and the mode volume V is obvious. The performance of the micro-cavity can be improved by adjusting the number of the micro-cavity and the length of the defect-cavity, and the ratio of Q/V can reach 43,750 in the communication band. The nano micro-cavity provides a new design idea and basis for the fabrication of tunable long-range surface plasmon wave filter in this paper.

  2. Low current performance of the Bern medical cyclotron down to the pA range

    NASA Astrophysics Data System (ADS)

    Auger, M.; Braccini, S.; Ereditato, A.; Nesteruk, K. P.; Scampoli, P.

    2015-09-01

    A medical cyclotron accelerating H- ions to 18 MeV is in operation at the Bern University Hospital (Inselspital). It is the commercial IBA 18/18 cyclotron equipped with a specifically conceived 6 m long external beam line ending in a separate bunker. This feature is unique for a hospital-based facility and makes it possible to conduct routine radioisotope production for PET diagnostics in parallel with multidisciplinary research activities, among which are novel particle detectors, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. Several of these activities, such as radiobiology experiments for example, require low current beams down to the pA range, while medical cyclotrons are designed for high current operation above 10 μA. In this paper, we present the first results on the low current performance of a PET medical cyclotron obtained by ion source, radio-frequency and main coil tuning. With this method, stable beam currents down to (1.5+/- 0.5 ) pA were obtained and measured with a high-sensitivity Faraday cup located at the end of the beam transport line.

  3. Langmuir probe study of a magnetically enhanced RF plasma source at pressures below 0.1 Pa

    NASA Astrophysics Data System (ADS)

    Kousal, Jaroslav; Tichý, Milan; Šebek, Ondřej; Čechvala, Juraj; Biederman, Hynek

    2011-08-01

    The majority of plasma polymerization sources operate at pressures higher than 1 Pa. At these pressures most common deposition methods do not show significant directionality. One way of enhancing the directional effects is to decrease the working pressure to increase the mean free path of the reactive molecules. The plasma source used in this work was designed to study the plasma polymerization process at pressures below 0.1 Pa. The source consists of the classical radio frequency (RF) (13.56 MHz, capacitive coupled) tubular reactor enhanced by an external magnetic circuit. The working gas is introduced into the discharge by a capillary. This forms a relatively localized zone of higher pressure where the monomer is activated. Due to the magnetic field, the plasma is constricted near the axis of the reactor with nearly collisionless gas flow. The plasma parameters were obtained using a double Langmuir probe. Plasma density in the range ni = 1013-1016 m-3 was obtained in various parts of the discharge under typical conditions. The presence of the magnetic field led to the presence of relatively strong electric fields (103 V m-1) and relatively high electron energies up to several tens of eV in the plasma.

  4. Effectiveness of Micro-Blowing Technique in Adverse Pressure Gradients

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.; Larosiliere, Louis M.; Hwang, Danny P.; Wood, Jerry R.

    2001-01-01

    The impact of the micro-blowing technique (MBT) on the skin friction and total drag of a strut in a turbulent, strong adverse-pressure-gradient flow is assessed experimentally over a range of subsonic Mach numbers (0.3 less than M less than 0.7) and reduced blowing fractions (0 less than or equal to 2F/C (sub f,o) less than or equal to 1.75). The MBT-treated strut is situated along the centerline of a symmetric 2-D diffuser with a static pressure rise coefficient of 0.6. In agreement with presented theory and earlier experiments in zero-pressure-gradient flows, the effusion of blowing air reduces skin friction significantly (e.g., by 60% at reduced blowing fractions near 1.75). The total drag of the treated strut with blowing is significantly lower than that of the treated strut in the limit of zero-blowing; further, the total drag is reduced below that of the baseline (solid-plate) strut, provided that the reduced blowing fractions are sufficiently high. The micro-blowing air is, however, deficient in streamwise momentum and the blowing leads to increased boundary-layer and wake thicknesses and shape factors. Diffuser performance metrics and wake surveys are used to discuss the impact of various levels of micro-blowing on the aerodynamic blockage and loss.

  5. Hydrostatic pressure sensor based on micro-cavities developed by the catastrophic fuse effect

    NASA Astrophysics Data System (ADS)

    Domingues, M. F.; Paixão, T.; Mesquita, E.; Alberto, N.; Antunes, P.; Varum, H.; André, P. S.

    2015-09-01

    In this work, an optical fiber hydrostatic pressure sensor based in Fabry-Perot micro-cavities is presented. These micro structures were generated by the recycling of optical fiber previously damaged by the fiber fuse effect, resulting in a cost effective solution when compared with the traditional methods used to produce similar micro-cavities. The developed sensor was tested for pressures ranging from 20.0 to 190.0 cmH2O and a sensitivity of 53.7 +/- 2.6 pm/cmH2O for hydrostatic pressures below to 100 cmH2O was achieved.

  6. Extended range of the Lockheed Martin coax Micro cryocooler

    NASA Astrophysics Data System (ADS)

    Frank, D.; Champagne, P.; Will, E.; Kaldas, G.; Sanders, L.; Roth, E.; Olson, J. R.

    2016-03-01

    This paper describes the higher cooling capability of the Lockheed Martin coax Micro cryocooler thermal mechanical unit. The design of the previously qualified TRL6 Micro (Nast et al., 2014) [1] was modified to accommodate over twice the input power, greatly increasing the cooling capability. These Micro units are in a split configuration with the cold head separated from the compressor. This unit was optimized for cooling at 105 K and provides cooling over a wide range of temperatures. With a weight below 450 g, this small unit is ideal for compact instruments. Load lines were obtained over a range of powers, cold tip temperatures and rejection temperatures. This testing raised the Technology Readiness Level to six.

  7. Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges

    PubMed Central

    Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

    2017-01-01

    Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics. PMID:28361867

  8. A dynamic pressure view cell for acoustic stimulation of fluids—Micro-bubble generation and fluid movement in porous media

    NASA Astrophysics Data System (ADS)

    Stewart, Robert A.; Shaw, J. M.

    2015-09-01

    The development and baseline operation of an acoustic view cell for observing fluids, and fluid-fluid and fluid-solid interfaces in porous media over the frequency range of 10-5000 Hz is described. This range includes the industrially relevant frequency range 500-5000 Hz that is not covered by existing devices. Pressure waveforms of arbitrary shape are generated in a 17.46 mm ID by 200 mm and 690.5 mm long glass tubes at flow rates up to 200 ml/min using a syringe pump. Peak-to-peak amplitudes exceeding 80 kPa are readily realized at frequencies from 10 to 5000 Hz in bubble free fluids when actuated with 20 Vpp as exemplified using castor oil. At resonant frequencies, peak-to-peak pressure amplitudes exceeding 500 kPa were obtained (castor oil at 2100 Hz when actuated with 20 Vpp). Impacts of vibration on macroscopic liquid-liquid and liquid-vapour interfaces and interface movement are illustrated. Pressure wave transmission and attenuation in a fluid saturated porous medium, randomly packed 250-330 μm spherical silica beads, is also demonstrated. Attenuation differences and frequency shifts in resonant peaks are used to detect the presence and generation of dispersed micro-bubbles (<180 μm diameter), and bubbles within porous media that are not readily visualized. Envisioned applications include assessment of the impacts of vibration on reaction, mass transfer, and flow/flow pattern outcomes. This knowledge will inform laboratory and pilot scale process studies, where nuisance vibrations may affect the interpretation of process outcomes, and large scale or in situ processes in aquifers or hydrocarbon reservoirs where imposed vibration may be deployed to improve aspects of process performance. Future work will include miscible interface observation and quantitative measurements in the bulk and in porous media where the roles of micro-bubbles comprise subjects of special interest.

  9. A dynamic pressure view cell for acoustic stimulation of fluids--Micro-bubble generation and fluid movement in porous media.

    PubMed

    Stewart, Robert A; Shaw, J M

    2015-09-01

    The development and baseline operation of an acoustic view cell for observing fluids, and fluid-fluid and fluid-solid interfaces in porous media over the frequency range of 10-5000 Hz is described. This range includes the industrially relevant frequency range 500-5000 Hz that is not covered by existing devices. Pressure waveforms of arbitrary shape are generated in a 17.46 mm ID by 200 mm and 690.5 mm long glass tubes at flow rates up to 200 ml/min using a syringe pump. Peak-to-peak amplitudes exceeding 80 kPa are readily realized at frequencies from 10 to 5000 Hz in bubble free fluids when actuated with 20 Vpp as exemplified using castor oil. At resonant frequencies, peak-to-peak pressure amplitudes exceeding 500 kPa were obtained (castor oil at 2100 Hz when actuated with 20 Vpp). Impacts of vibration on macroscopic liquid-liquid and liquid-vapour interfaces and interface movement are illustrated. Pressure wave transmission and attenuation in a fluid saturated porous medium, randomly packed 250-330 μm spherical silica beads, is also demonstrated. Attenuation differences and frequency shifts in resonant peaks are used to detect the presence and generation of dispersed micro-bubbles (<180 μm diameter), and bubbles within porous media that are not readily visualized. Envisioned applications include assessment of the impacts of vibration on reaction, mass transfer, and flow/flow pattern outcomes. This knowledge will inform laboratory and pilot scale process studies, where nuisance vibrations may affect the interpretation of process outcomes, and large scale or in situ processes in aquifers or hydrocarbon reservoirs where imposed vibration may be deployed to improve aspects of process performance. Future work will include miscible interface observation and quantitative measurements in the bulk and in porous media where the roles of micro-bubbles comprise subjects of special interest.

  10. Blood lactate changes in men during graded workloads at normal atmospheric pressure (100 kPa) and under simulated caisson conditions (400 kPa).

    PubMed

    Neubauer, B; Tetzlaff, K; Buslaps, C; Schwarzkopf, J; Bettinghausen, E; Rieckert, H

    1999-05-01

    A hyperbaric environment may influence lactate metabolism due to hyperoxia affecting biochemical pathways. The purpose of our study was to determine the blood lactate levels occurring at high workloads in a sample of professional divers under simulated caisson conditions. The ambient air pressure was equivalent to a diving depth of 30 m of seawater (400 kPa). A total of 23 healthy male subjects performed graded bicycle exercise in a dry hyperbaric chamber up to a maximum of 3.5 W kg(-1) body weight at normal (100 kPa) and elevated ambient air pressure (400 kPa). The blood lactate level and the heart rate were measured. In comparison with control conditions, the heart rate and the peripheral blood lactate level were significantly lower at depth for all workloads. The differences between the normobaric and hyperbaric lactate values may be explained by an overall improvement in lactate metabolism at elevated ambient pressure, especially in the working muscles and the organs responsible for the lactate reduction, i.e., the liver. The reduced heart rate may be an effect of the improved tissue oxygen supply at depth.

  11. Micro-Pressure Sensors for Future Mars Missions

    NASA Technical Reports Server (NTRS)

    Catling, David C.

    1996-01-01

    The joint research interchange effort was directed at the following principal areas: u further development of NASA-Ames' Mars Micro-meteorology mission concept as a viable NASA space mission especially with regard to the science and instrument specifications u interaction with the flight team from NASA's New Millennium 'Deep-Space 2' (DS-2) mission with regard to selection and design of micro-pressure sensors for Mars u further development of micro-pressure sensors suitable for Mars The research work undertaken in the course of the Joint Research Interchange should be placed in the context of an ongoing planetary exploration objective to characterize the climate system on Mars. In particular, a network of small probes globally-distributed on the surface of the planet has often been cited as the only way to address this particular science goal. A team from NASA Ames has proposed such a mission called the Micrometeorology mission, or 'Micro-met' for short. Surface pressure data are all that are required, in principle, to calculate the Martian atmospheric circulation, provided that simultaneous orbital measurements of the atmosphere are also obtained. Consequently, in the proposed Micro-met mission a large number of landers would measure barometric pressure at various locations around Mars, each equipped with a micro-pressure sensor. Much of the time on the JRI was therefore spent working with the engineers and scientists concerned with Micro-met to develop this particular mission concept into a more realistic proposition.

  12. Dynamic impact and pressure analysis of the insensitive munitions container PA103 with modified design features

    SciTech Connect

    Handy, K.D.

    1993-06-01

    This report presents analytical analyses of the insensitive munitions container PA103, with modified design features for a static internal pressure of 500 psi and for a dynamic impact resulting from a 7-ft free fall onto a rigid surface. The modified design features addressed by the analyses were the inclusion of a score pattern on the container cylindrical body and a plastic plate (fuse) sandwiched between metal flanges on the container end. The objectives of both the pressure and impact analyses were to determine if the induced stresses at the score patterns in the cylindrical body of the container were sufficient to induce failure. Analytical responses of the container to the imposed loads were obtained with finite element analysis methodology. The computer codes ABAQUS and VEC/DYNA3D were used to obtain the results. Results of the pressure analysis indicate that failure of the container body would be expected to occur at the score pattern for a static internal pressure of 500 psi. Also, results from three impact orientations for a 7-ft drop indicate that membrane stresses in the vicinity of the score pattern are above critical crack growth stress magnitudes, especially at low ([minus]60[degrees]F) temperatures.

  13. Dynamic impact and pressure analysis of the insensitive munitions container PA103 with modified design features

    SciTech Connect

    Handy, K.D.

    1993-06-01

    This report presents analytical analyses of the insensitive munitions container PA103, with modified design features for a static internal pressure of 500 psi and for a dynamic impact resulting from a 7-ft free fall onto a rigid surface. The modified design features addressed by the analyses were the inclusion of a score pattern on the container cylindrical body and a plastic plate (fuse) sandwiched between metal flanges on the container end. The objectives of both the pressure and impact analyses were to determine if the induced stresses at the score patterns in the cylindrical body of the container were sufficient to induce failure. Analytical responses of the container to the imposed loads were obtained with finite element analysis methodology. The computer codes ABAQUS and VEC/DYNA3D were used to obtain the results. Results of the pressure analysis indicate that failure of the container body would be expected to occur at the score pattern for a static internal pressure of 500 psi. Also, results from three impact orientations for a 7-ft drop indicate that membrane stresses in the vicinity of the score pattern are above critical crack growth stress magnitudes, especially at low ({minus}60{degrees}F) temperatures.

  14. Range 7 Scanner Integration with PaR Robot Scanning System

    NASA Technical Reports Server (NTRS)

    Schuler, Jason; Burns, Bradley; Carlson, Jeffrey; Minich, Mark

    2011-01-01

    An interface bracket and coordinate transformation matrices were designed to allow the Range 7 scanner to be mounted on the PaR Robot detector arm for scanning the heat shield or other object placed in the test cell. A process was designed for using Rapid Form XOR to stitch data from multiple scans together to provide an accurate 3D model of the object scanned. An accurate model was required for the design and verification of an existing heat shield. The large physical size and complex shape of the heat shield does not allow for direct measurement of certain features in relation to other features. Any imaging devices capable of imaging the entire heat shield in its entirety suffers a reduced resolution and cannot image sections that are blocked from view. Prior methods involved tools such as commercial measurement arms, taking images with cameras, then performing manual measurements. These prior methods were tedious and could not provide a 3D model of the object being scanned, and were typically limited to a few tens of measurement points at prominent locations. Integration of the scanner with the robot allows for large complex objects to be scanned at high resolution, and for 3D Computer Aided Design (CAD) models to be generated for verification of items to the original design, and to generate models of previously undocumented items. The main components are the mounting bracket for the scanner to the robot and the coordinate transformation matrices used for stitching the scanner data into a 3D model. The steps involve mounting the interface bracket to the robot's detector arm, mounting the scanner to the bracket, and then scanning sections of the object and recording the location of the tool tip (in this case the center of the scanner's focal point). A novel feature is the ability to stitch images together by coordinates instead of requiring each scan data set to have overlapping identifiable features. This setup allows models of complex objects to be developed

  15. Thermal and Pressure-Assisted Thermal Destruction Kinetics for Spores of Type A Clostridium botulinum and Clostridium sporogenes PA3679.

    PubMed

    Reddy, N Rukma; Patazca, Eduardo; Morrissey, Travis R; Skinner, Guy E; Loeza, Viviana; Schill, Kristin M; Larkin, John W

    2016-02-01

    The purpose of this study was to determine the inactivation kinetics of the spores of the most resistant proteolytic Clostridium botulinum strains (Giorgio-A and 69-A, as determined from an earlier screening study) and of Clostridium sporogenes PA3679 and to compare the thermal and pressure-assisted thermal resistance of these spores. Spores of these strains were prepared using a biphasic medium method. C. sporogenes PA3679 spores were heat treated before spore preparation. Using laboratory-scale and pilot-scale pressure test systems, spores of Giorgio-A, 69-A, and PA3679 suspended in ACES [N-(2-acetamido)-2-aminoethanesulfonic acid] buffer (pH 7.0) were exposed to various combinations of temperature (93 to 121°C) and pressure (0.1 to 750 MPa) to determine their resistance. More than a 5-log reduction occurred after 3 min at 113°C for spores of Giorgio-A and 69-A and after 5 min at 117°C for spores of PA3679. A combination of high temperatures (93 to 121°C) and pressures yielded greater log reductions of spores of Giorgio-A, 69-A, and PA3679 compared with reduction obtained with high temperatures alone. No survivors from initial levels (>5.0 log CFU) of Giorgio-A and 69-A were detected when processed at a combination of high temperature (117 and 121°C) and high pressure (600 and 750 MPa) for <1 min in a pilot-scale pressure test system. Increasing pressure from 600 to 750 MPa at 117°C decreased the time from 2.7 to 1 min for a >4.5-log reduction of PA3679 spores. Thermal D-values of Giorgio-A, 69-A, and PA3679 spores decreased (i.e., 29.1 to 0.33 min for Giorgio-A, 40.5 to 0.27 min for 69-A, and 335.2 to 2.16 min for PA3679) as the temperature increased from 97 to 117°C. Pressure-assisted thermal D-values of Giorgio-A, 69-A, and PA3679 also decreased as temperature increased from 97 to 121°C at both pressures (600 and 750 MPa) (i.e., 17.19 to 0.15 min for Giorgio-A, 9.58 to 0.15 min for 69-A, and 12.93 to 0.33 min for PA3679 at 600 MPa). At higher

  16. First-principles investigations of equation of states and phase transitions in PaN under pressure

    NASA Astrophysics Data System (ADS)

    Modak, P.; Verma, Ashok K.

    2013-02-01

    We have studied equation of states (EOS) and pressure induced structural transitions of PaN using first principles electronic structure and total energy calculations. We have predicted that PaN undergoes a structural transition from NaCl to R-3m structure at around 55 GPa pressure. We have also calculated the enthalpy as a function of rhombohedral angle at constant pressures for the Buerger pathway of B1-B2 transition where R-3m is the intermediate state. We have showed that NaCl structure becomes mechanically unstable and f electrons of Pa plays crucial role to stabilize R-3m structure instead of CsCl at high pressure.

  17. Final report on SIM.M.P-S6: Differential pressure comparison from 50 Pa to 500 Pa with a liquid column manometer between CENAM (Mexico) and INTI-Fisica y Metrologia (Argentina)

    NASA Astrophysics Data System (ADS)

    Torres-Guzman, Jorge; Forastieri, Juan; Zúñiga, Sinuhé

    2011-01-01

    A differential pressure comparison was performed between CENAM (Mexico) and INTI (Argentina) by means of a liquid column manometer. The measuring range was 50 Pa to 500 Pa. CENAM calibrated the transfer standard at the beginning and at the end of the comparison. The transfer standard used was a Dwyer liquid column manometer model Microtector with an accuracy class of 0.013% of the reading. The compared pressure points were (50, 75, 125, 200, 250, 300, 350, 400, 450, 500) Pa. The uncertainty sources to be evaluated included at least the following: (a) uncertainty due to the standard used by the laboratory; (b) uncertainty due to repeatability; (c) uncertainty due to resolution; (d) uncertainty due to hysteresis; (e) uncertainty due to zero drift. The criteria used to compare the results obtained were the normalized error equation (En). The results obtained by the laboratories were compatible according to the criteria |En| <= 1. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  18. Ultra-low-pressure sputtering to improve exchange bias and tune linear ranges in spin valves

    NASA Astrophysics Data System (ADS)

    Tang, XiaoLi; Yu, You; Liu, Ru; Su, Hua; Zhang, HuaiWu; Zhong, ZhiYong; Jing, YuLan

    2017-05-01

    A series of CoFe/IrMn exchange bilayers was grown by DC-sputtering at different ultra-low argon pressures ranging from 0.008 to 0.1 Pa. This pressure range was one to two orders lower than the normal sputtering pressure. Results revealed that the exchange bias increased from 140 to 250 Oe in CoFe(10 nm)/IrMn (15 nm) bilayers of fixed thickness because of the improved crystalline structure and morphological uniformity of films. Since ferromagnetic /antiferromagnetic (FM/AF) bilayers are always used in linear magnetic sensors as detection layers, the varying exchange bias can successfully achieve tunable linear range in a crossed pinning spin valve. The linear range could be adjustable from -80 Oe - +80 Oe to -150 Oe - +150 Oe on the basis of giant magnetoresistance responses. Therefore, this method provides a simple method to tune the operating range of magnetic field sensors.

  19. Micro Electro-Mechanical System (MEMS) Pressure Sensor for Footwear

    DOEpatents

    Kholwadwala, Deepesh K.; Rohrer, Brandon R.; Spletzer, Barry L.; Galambos, Paul C.; Wheeler, Jason W.; Hobart, Clinton G.; Givler, Richard C.

    2008-09-23

    Footwear comprises a sole and a plurality of sealed cavities contained within the sole. The sealed cavities can be incorporated as deformable containers within an elastic medium, comprising the sole. A plurality of micro electro-mechanical system (MEMS) pressure sensors are respectively contained within the sealed cavity plurality, and can be adapted to measure static and dynamic pressure within each of the sealed cavities. The pressure measurements can provide information relating to the contact pressure distribution between the sole of the footwear and the wearer's environment.

  20. Modeling High Pressure Micro Hollow Cathode Discharges

    DTIC Science & Technology

    2007-11-02

    calculations in glow discharge in argon and neon . A Monte Carlo simulation of the ions and Grant 033083 – Final report 7 the fast neutrals generated...in high pressure xenon or in rare gas mixtures containing xenon are of interest in the context of UV and VUV generation. Numerical experiments on...The shape of the calculated characteristic is similar to those measured by Schoenbach et al1 in argon and by Moselhy and Schoenbach9 in xenon . There

  1. High-Pressure Range Shock Wave Data for Syntactic Foams

    NASA Astrophysics Data System (ADS)

    Ribeiro, J.; Mendes, R.; Plaksin, I.; Campos, J.; Capela, C.

    2009-12-01

    Syntactic foams [SF] are a porous composite material resulting from the mixture of Hollow Glass Micro Spheres [HGMS] with a polymeric binder. Beyond a set of technological advantages over the polymer considered alone, SF present as an essential feature the possibility to control in wide limits the amount, the shape and the size of the pores and for that reason are being used for benchmarking in the area of shock wave [SW] behavior of porous materials. In this paper, SW loading experiments of SF samples were performed in order to assess the high-pressure range Hugoniot equation of state as a function of the SF initial density. Hugoniot data were assessed coupling the SW velocity within the SF samples with the SW velocity in a reference material or with manganin gauge results. The results obtained present a significant variation with the initial specific mass and can be described with appreciable precision by the Thouvenin/Hofmann Plate Gap model, while the concordance between the experimental results and the Grüneisen model seems to be very dependent on the Grüneisen coefficient values.

  2. A Micro Pressure Sensor with SU-8 Polymer

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaohong; Yin, Yonghua; Zheng, Xiaohu

    This paper investigated novel wireless RF pressure sensor fabricated with SU-8 polymer. To achieve highly simplified fabrication processes and designs for high-reliable operation, a passive wireless sensors were researched. SU-8 polymer-based micro pressure sensor was fabricated by micro-electro-mechenical system (MEMS) based batch process. The sensor consists of an inductor (L) interconnected with pressure-variable capacitor (C) to form a LC resonant circuit. Fabricated devices measure 4 × 3 mm2 in size and houses 9 turns of Cu electro-plated 100 nH coil. In this system, RF signal was transmitted from external antenna to the fabricated LC resonator. By detecting this abrupt resonant frequency shift of the fabricated device, the pressure change of the device can be measured by wireless method.

  3. Compressible fiber optic micro-Fabry-Pérot cavity with ultra-high pressure sensitivity.

    PubMed

    Wang, Ying; Wang, D N; Wang, Chao; Hu, Tianyi

    2013-06-17

    We propose and demonstrate a pressure sensor based on a micro air bubble at the end facet of a single mode fiber fusion spliced with a silica tube. When immersed into the liquid such as water, the air bubble essentially acts as a Fabry-Pérot interferometer cavity. Such a cavity can be compressed by the environmental pressure and the sensitivity obtained is >1000 nm/kPa, at least one order of magnitude higher than that of the diaphragm-based fiber-tip sensors reported so far. The compressible Fabry-Pérot interferometer cavity developed is expected to have potential applications in highly sensitive pressure and/or acoustic sensing.

  4. New Functionalities of PA6,6 Fabric Modified by Atmospheric Pressure Plasma and Grafted Glycidyl Methacrylate Derivatives

    USDA-ARS?s Scientific Manuscript database

    Oxidative atmospheric pressure plasma was utilized to activate surface of PA 6,6 fabrics followed by graft copolymerization of glycidyl methacrylate (GMA) and further reacted with triethylene tetramine (TETA), quaternary ammonium chitosan (HTCC) or cyclodextrin (CD). The inner CD cavity was complexe...

  5. Regulation of pressure anisotropy in the solar wind: processes within inertial range of turbulence

    NASA Astrophysics Data System (ADS)

    Strumik, M.; Schekochihin, A. A.; Squire, J.; Bale, S. D.

    2016-12-01

    Dynamics of weakly collisional plasmas may lead to thermal pressure anisotropies that are driven by velocity shear, plasma expansion/compression or temperature gradients. The pressure anisotropies can provide free energy for the growth of micro-scale instabilities, like the mirror of firehose instabilities, that are commonly believed to constrain the pressure anisotropy in the solar wind if appropriate thresholds are exceeded. We discuss possible alternative mechanisms of regulation of the pressure anisotropy in the inertial range of solar wind turbulence that provide β-dependent constraints on the amplitude of fluctuations of pressure components and other quantities. In particular it is shown that double-adiabatic (CGL) closure for magnetohydrodynamic regime leads to 1/β scaling of the amplitude of the pressure component fluctuations and the pressure anisotropy. Both freely decaying and forced turbulence are discussed based on results of 3D numerical simulations and analytical theoretical predictions. The theoretical results are contrasted with WIND spacecraft measurements.

  6. Pulmonary Oxygen Toxicity When Partial Pressure Is 2 atm (200 kPa)

    DTIC Science & Technology

    2013-04-01

    fsw for 80 minutes three times in a day, or, in principle, to 35 fsw for 25 minutes nine times. A diver repeating exposures to that extent could be...45.4 ATA, or 980 to 1470 fsw ) (16). Helium at 3100 kPa has similar density to air at 400 kPa, or about twice the density encountered in these

  7. Report of pilot study CCM.P-P1 for international comparison of absolute pressure measurements in gas from 3 × 10-9 Pa to 9 × 10-4 Pa

    NASA Astrophysics Data System (ADS)

    Yoshida, Hajime; Arai, Kenta; Komatsu, Eiichi; Fujii, Kenichi; Bock, Thomas; Jousten, Karl

    2015-01-01

    A bilateral comparison of absolute gas pressure measurements from 3 × 10-9 Pa to 9 × 10-4 Pa was performed between the National Metrology Institute of Japan (NMIJ) and Physikalisch-Technische Bundesanstalt (PTB). It is a pilot study CCM.P-P1 for the next international comparison in this pressure range to test the stability of ultrahigh vacuum gauges (UHV gauges) as transfer standards. Two spinning rotor gauges (SRGs), an axial-symmetric transmission gauge (ATG), and an extractor gauge (EXG) were used as transfer standards. The calibration ratio of one SRG was sufficiently stable, but the other was not. This result indicates that improvements in the transport mechanism for SRG are needed. The two ionization gauges ATG and EXG, on the other hand, were sufficiently stable. Provisional equivalence of the pressures realized by the primary standards at NMIJ and PTB was found. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by CCM-WGS.

  8. microRNAs in Essential Hypertension and Blood Pressure Regulation.

    PubMed

    Marques, Francine Z; Charchar, Fadi J

    2015-01-01

    Unravelling the complete genetic predisposition to high blood pressure (BP) has proven to be challenging. This puzzle and the fact that coding regions of the genome account for less than 2 % of the entire human DNA support the hypothesis that mechanisms besides coding genes are likely to contribute to BP regulation. Non-coding RNAs, especially microRNAs, are emerging as key players of transcription regulation in both health and disease states. They control basic functions in virtually all cell types relevant to the cardiovascular system and, thus, a direct involvement with BP regulation is highly probable. Here we review the literature about microRNAs associated with regulation of BP and hypertension, highlighting investigations, methodology and difficulties arising in the field. These molecules are being studied for exploitation in diagnostics, prognostics and therapeutics in many diseases. There have been some studies that examined biological fluid microRNAs as biomarkers for hypertension, but most remain inconclusive due to the small sample sizes and differences in methodological standardisation. Fewer studies have analysed tissue microRNA levels in vascular smooth muscle cells and the kidney. Others focused on the interaction between single nucleotide polymorphisms and microRNA binding sites. Studies in animals have shown that angiotensin II, high-salt diet and exercise change microRNA levels in hypertension. Treatment of spontaneously hypertensive rats with a miR-22 inhibitor and treatment of hypertensive Schlager BPH/2J mice with a miR-181a mimic decreased their BP. This supports the use of microRNAs as therapeutic targets in hypertension, and future studies should test the use of other microRNAs found in human association studies. In conclusion, there is a clear need of increased pace of human, animal and functional studies to help us understand the multifaceted roles of microRNAs as critical regulators of the development and physiology of BP.

  9. MicroScale - Atmospheric Pressure Plasmas

    SciTech Connect

    Sankaran, Mohan

    2012-01-25

    Low-temperature plasmas play an essential role in the manufacturing of integrated circuits which are ubiquitous in modern society. In recent years, these top-down approaches to materials processing have reached a physical limit. As a result, alternative approaches to materials processing are being developed that will allow the fabrication of nanoscale materials from the bottom up. The aim of our research is to develop a new class of plasmas, termed “microplasmas” for nanomaterials synthesis. Microplasmas are a special class of plasmas formed in geometries where at least one dimension is less than 1 mm. Plasma confinement leads to several unique properties including high-pressure stability and non-equilibrium that make microplasams suitable for nanomaterials synthesis. Vapor-phase precursors can be dissociated to homogeneously nucleate nanometer-sized metal and alloyed nanoparticles. Alternatively, metal salts dispersed in liquids or polymer films can be electrochemically reduced to form metal nanoparticles. In this talk, I will discuss these topics in detail, highlighting the advantages of microplasma-based systems for the synthesis of well-defined nanomaterials.

  10. Pressure effects on icosahedral short range order in undercooled copper

    NASA Astrophysics Data System (ADS)

    Celino, Massimo; Coppari, Federica; Di Cicco, Andrea

    2010-02-01

    There is not a wide consensus on the role played by the icosahedral short range order on the stability of undercooled simple metals. The scenario is even less clear for undercooled metals under external pressure. Classical molecular dynamics simulations are performed to explain experimental results recently obtained on liquid and undercooled liquid copper under pressure. The atomic configurations are characterized by a common neighbor analysis to reveal the icosahedral short range order and its relation with external pressure. External pressure increases the probability to find atomic bonds with icosahedral symmetry both in the liquid and in the undercooled copper.

  11. PaCO2 in Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT)

    PubMed Central

    Ambalavanan, Namasivayam; Carlo, Waldemar A.; Wrage, Lisa A.; Das, Abhik; Laughon, Matthew; Cotten, C. Michael; Kennedy, Kathleen A.; Laptook, Abbot R.; Shankaran, Seetha; Walsh, Michele C.; Higgins, Rosemary D.

    2015-01-01

    Objective To determine the association of PaCO2 with severe intraventricular hemorrhage (sIVH), bronchopulmonary dysplasia (BPD), and neurodevelopmental impairment (NDI) at 18–22 months in premature infants. Design Secondary exploratory data analysis of SUPPORT. Setting Multiple referral NICUs. Patients 1316 infants 24 0/7 to 27 6/7 weeks gestation randomized to different oxygenation (SpO2 target 85–89% vs 91–95%) and ventilation strategies. Main Outcome Measures Blood gases from postnatal days 0–14 were analyzed. Five PaCO2 variables were defined: minimum [Min], maximum [Max], standard deviation, average (time-weighted), and a 4 level categorical variable (hypercapnic [highest quartile of Max PaCO2], hypocapnic [lowest quartile of Min PaCO2], fluctuators [both hypercapnia and hypocapnia], and normocapnic [middle two quartiles of Max and Min PaCO2]). PaCO2 variables were compared for infants with and without sIVH, BPD, and NDI (+/− death). Multivariable logistic regression models were developed for adjusted results. Results sIVH, BPD, and NDI (+/− death) were associated with hypercapnic infants and fluctuators. Association of Max PaCO2 and outcomes persisted after adjustment (Per 10 mmHg increase: sIVH/death: OR 1.27 [1.13–1.41]; BPD/death: OR 1.27 [1.12–1.44]; NDI/death: OR 1.23 [1.10–1.38], Death: OR 1.27 [1.12–1.44], all p <0.001). No interaction was found between PaCO2 category and SpO2 treatment group for sIVH/death, NDI/death, or death. Max PaCO2 was positively correlated with maximum FiO2 (rs0.55, p<0.0001) & ventilator days (rs0.61, p<0.0001). Conclusions Higher PaCO2 was an independent predictor of sIVH/death, BPD/death, and NDI/death. Further trials are needed to evaluate optimal PaCO2 targets for high risk infants. PMID:25425651

  12. Integrated coaxial-hollow micro dielectric-barrier-discharges for a large-area plasma source operating at around atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Sakai, Osamu; Kishimoto, Yutaka; Tachibana, Kunihide

    2005-02-01

    An integrated structure of coaxial-hollow micro dielectric-barrier-discharges has been developed by stacking two metal meshes covered with insulating material. The test panel has an effective area of 50 mm diameter in which hundreds of hollow structures are assembled with a unit hollow area of 0.2 × 1.7 mm2. He or N2 was used as the discharge gas in the pressure range from 20 to 100 kPa and the firing voltage was less than 2 kV, even at the maximum pressure. The intensity of each microdischarge was observed to be uniform over the whole area throughout the pressure range, and its time evolution during one discharge pulse was analysed through two-dimensional microscopic observation with a gated CCD camera. In a gas flow regime through the coaxial hollow structures, several significant changes of the discharge properties were observed, such as impurity reduction, decrease in discharge voltage and cooling of the neutral gas. The fundamental plasma parameters were measured using a single probe in the downstream region of microdischarges using an auxiliary flat electrode set apart from the mesh electrode plane. The occurrence of an extended glow with a length of some millimetres was observed in He but not in N2. The electron density derived by the probe data in He at 100 kPa was ~3 × 1011 cm-3, suggesting a value of more than 1012 cm-3 in the active microdischarge region.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  14. Peak Pressures and PaO2/FiO2 Ratios Are Associated With Adverse Outcomes in Patients on Mechanical Ventilators.

    PubMed

    Whiting, Jeremy; Edriss, Hawa; Yang, Shengping; Nugent, Kenneth

    2016-06-01

    Patients requiring mechanical ventilation can have complications related to their underlying diseases and hospital-related events. It is possible that easily obtained information early in the course of mechanical ventilation can provide information about important outcomes. Medical records from 281 episodes of mechanical ventilation in the medical intensive care unit were reviewed to collect information on patient demographics, admitting diagnoses, laboratory tests, duration of mechanical ventilation, the development of ventilator-associated events and mortality. Ventilator pressures from day 2 were analyzed for this study. Most patients (72.7%) were ≥50 years, 53.8% were men and 66.3% had a body mass index (BMI) ≥ 25kg/m(2).The mean Acute Physiology and Chronic Healthy Evaluation II score was 13.6 ± 5.9. The median initial PaO2/FiO2 was 240 with interquartile range of 177-414. The median duration of ventilation was 4 days (interquartile range: 2-9 days). A PaO2/FiO2 ratio < 100 was associated with increased mortality compared with PaO2/FiO2 ratio > 500, and a BMI > 30kg/m(2) was associated with decreased mortality compared with normal BMIs. A PaO2/FiO2 ratio < 100 and BMIs <18.5kg/m(2) or >30kg/m(2) were all associated with having a ventilator-associated event. There was a positive correlation between peak pressure (day 2) and the duration of ventilation (r = 0.263, P = 0.007). Easily available information collected on day 2 of mechanical ventilation can help identify patients at risk for poor outcomes, including the duration of mechanical ventilation, the development of ventilator-associated complications and mortality. Prospective studies measuring peak pressures are needed to evaluate the utility of this simple measurement in the management of patients requiring mechanical ventilation. Published by Elsevier Inc.

  15. Determination of Phonation Instability Pressure and Phonation Pressure Range in Excised Larynges

    ERIC Educational Resources Information Center

    Zhang, Yu; Reynders, William J.; Jiang, Jack J.; Tateya, Ichiro

    2007-01-01

    Purpose: The present study was a methodological study designed to reveal the dynamic mechanisms of phonation instability pressure (PIP) using bifurcation analysis. Phonation pressure range (PPR) was also proposed for assessing the pressure range of normal vocal fold vibrations. Method: The authors first introduced the concept of bifurcation on the…

  16. Determination of Phonation Instability Pressure and Phonation Pressure Range in Excised Larynges

    ERIC Educational Resources Information Center

    Zhang, Yu; Reynders, William J.; Jiang, Jack J.; Tateya, Ichiro

    2007-01-01

    Purpose: The present study was a methodological study designed to reveal the dynamic mechanisms of phonation instability pressure (PIP) using bifurcation analysis. Phonation pressure range (PPR) was also proposed for assessing the pressure range of normal vocal fold vibrations. Method: The authors first introduced the concept of bifurcation on the…

  17. Cell Membranes Under Hydrostatic Pressure Subjected to Micro-Injection

    NASA Astrophysics Data System (ADS)

    Vassilev, Vassil M.; Kostadinov, Kostadin G.; Mladenov, Ivaïlo M.; Shulev, Assen A.; Stoilov, Georgi I.; Djondjorov, Peter A.

    2011-04-01

    The work is concerned with the determination of the mechanical behaviour of cell membranes under uniform hydrostatic pressure subject to micro-injections. For that purpose, assuming that the shape of the deformed cell membrane is axisymmetric a variational statement of the problem is developed on the ground of the so-called spontaneous curvature model. In this setting, the cell membrane is regarded as an axisymmetric surface in the three-dimensional Euclidean space providing a stationary value of the shape energy functional under the constraint of fixed total area and fixed enclosed volume. The corresponding Euler-Lagrange equations and natural boundary conditions are derived, analyzed and used to express the forces and moments in the membrane. Several examples of such surfaces representing possible shapes of cell membranes under pressure subjected to micro injection are determined numerically.

  18. Pressure activated interconnection of micro transfer printed components

    NASA Astrophysics Data System (ADS)

    Prevatte, Carl; Guven, Ibrahim; Ghosal, Kanchan; Gomez, David; Moore, Tanya; Bonafede, Salvatore; Raymond, Brook; Trindade, António Jose; Fecioru, Alin; Kneeburg, David; Meitl, Matthew A.; Bower, Christopher A.

    2016-05-01

    Micro transfer printing and other forms of micro assembly deterministically produce heterogeneously integrated systems of miniaturized components on non-native substrates. Most micro assembled systems include electrical interconnections to the miniaturized components, typically accomplished by metal wires formed on the non-native substrate after the assembly operation. An alternative scheme establishing interconnections during the assembly operation is a cost-effective manufacturing method for producing heterogeneous microsystems, and facilitates the repair of integrated microsystems, such as displays, by ex post facto addition of components to correct defects after system-level tests. This letter describes pressure-concentrating conductor structures formed on silicon (1 0 0) wafers to establish connections to preexisting conductive traces on glass and plastic substrates during micro transfer printing with an elastomer stamp. The pressure concentrators penetrate a polymer layer to form the connection, and reflow of the polymer layer bonds the components securely to the target substrate. The experimental yield of series-connected test systems with >1000 electrical connections demonstrates the suitability of the process for manufacturing, and robustness of the test systems against exposure to thermal shock, damp heat, and mechanical flexure shows reliability of the resulting bonds.

  19. Ozone formation in pulsed SDBD in a wide pressure range

    NASA Astrophysics Data System (ADS)

    Starikovskiy, Andrey; Nudnova, Maryia; mipt Team

    2011-10-01

    Ozone concentration in surface anode-directed DBD for wide pressure range (150 - 1300 torr) was experimentally measured. Voltage and pressure effect were investigated. Reduced electric field was measured for anode-directed and cathode-directed SDBD. E/n values in cathode-directed SDBD is higher than in cathode-directed on 50 percent at atmospheric pressure. E/n value increase leads to decrease the rate of oxygen dissociation and Ozone formation at lower pressures. Radiating region thickness of sliding discharge was measured. Typical thickness of radiating zone is 0.4-1.0 mm within pressure range 220-740 torr. It was shown that high-voltage pulsed nanosecond discharge due to high E/n value produces less Ozone with compare to other discharges. Kinetic model was proposed to describe Ozone formation in the pulsed nanosecond SDBD.

  20. Pulsed electron beam propagation in gases under pressure of 6.6 kPa in drift tube

    NASA Astrophysics Data System (ADS)

    Kholodnaya, G. E.; Sazonov, R. V.; Ponomarev, D. V.; Remnev, G. E.; Poloskov, A. V.

    2017-02-01

    This paper presents the results of an investigation of pulsed electron beam transport propagated in a drift tube filled with different gases (He, H2, N2, Ar, SF6, and CO2). The total pressure in the drift tube was 6.6 kPa. The experiments were carried out using a TEA-500 pulsed electron accelerator. The electron beam was propagated in the drift tube composed of two sections equipped with reverse current shunts. Under a pressure of 6.6 kPa, the maximum value of the electron beam charge closed on the walls of the drift tube was recorded when the beam was propagated in hydrogen and carbon dioxide. The minimum value of the electron beam charge closed on the walls of the drift tube was recorded for sulfur hexafluoride. The visualization of the pulsed electron beam energy losses onto the walls of the drift chamber was carried out using radiation-sensitive film.

  1. CONFERENCE NOTE: Comité Consultatif pour la Masse et les grandeurs apparentées (CCM), High Pressure and Medium Pressure Working Groups, Second International Seminar on Pressure Metrology from 1 kPa to 1 GPa

    NASA Astrophysics Data System (ADS)

    1992-01-01

    The seminar will be held from 2 to 4 June 1993, preceding the next meeting of the CCM, at the Laboratoire National d'Essais (LNE), 1 rue Gaston Boissier, 75015 Paris, France. Scope of the Seminar The purpose of the seminar is to review the state of the art of pressure measurements in the 1 kPa to 1 GPa range and to present original and innovative contributions from standards laboratories and industry. Main Topics The seminar will be organized in six sessions as follows: Liquid-column manometers Piston gauge pressure standards Properties of liquids and gases relevant to pressure metrology Pressure transducers and transfer standards Pressure standard comparison (methods and results) Dynamic pressure measurements. Each topic will be introduced by a review paper presented by a session chairman. A final session, coordinated by Dr G F Molinar (IMGC), Chairman of the CCM High Pressure Working Group, and Dr P Stuart (NPL), Chairman of the CCM Medium Pressure Working Group, will deal with: Actual limits of accuracy of static pressure measurements in fluid media Fundamental problems in pressure metrology between I kPa and 1 GPa. Call for Papers Papers should be prepared for oral presentation and will be refereed by the session chairmen. The Proceedings will be published as a special issue of Metrologia. Papers should be written according to the instructions for authors printed on the inside back cover of this journal. A one-page abstract should be sent to Dr Molinar at the IMGC, to arrive before 31 January 1993. A participation fee of 900 FFr (175 US) will be charged. This will cover general expenses and a copy of the Proceedings. Hotel reservations, meals and transport are not included. Organizers For further information please contact: 1993 CCM Pressure Seminar, Dr G F Molinar, Istituto di Metrologia "G Colonnetti", Strada delle Cacce 73, 1-10135 Torino, Italy telephone (39) 11 39771; telex 212209 IMGCTO-I; fax (39) 11 346761. Contact at the LNE: J C Legras, telephone (33

  2. Peristaltic pump-based low range pressure sensor calibration system

    SciTech Connect

    Vinayakumar, K. B.; Naveen Kumar, G.; Rajanna, K. E-mail: krajanna2011@gmail.com; Nayak, M. M.; Dinesh, N. S.

    2015-11-15

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  3. Peristaltic pump-based low range pressure sensor calibration system

    NASA Astrophysics Data System (ADS)

    Vinayakumar, K. B.; Naveen Kumar, G.; Nayak, M. M.; Dinesh, N. S.; Rajanna, K.

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  4. Peristaltic pump-based low range pressure sensor calibration system.

    PubMed

    Vinayakumar, K B; Naveen Kumar, G; Nayak, M M; Dinesh, N S; Rajanna, K

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  5. Effects of respiratory rate, plateau pressure, and positive end-expiratory pressure on PaO2 oscillations after saline lavage.

    PubMed

    Baumgardner, James E; Markstaller, Klaus; Pfeiffer, Birgit; Doebrich, Marcus; Otto, Cynthia M

    2002-12-15

    One of the proposed mechanisms of ventilator-associated lung injury is cyclic recruitment of atelectasis. Collapse of dependent lung regions with every breath should lead to large oscillations in PaO2 as shunt varies throughout the respiratory cycle. We placed a fluorescence-quenching PO2 probe in the brachiocephalic artery of six anesthetized rabbits after saline lavage. Using pressure-controlled ventilation with oxygen, ventilator settings were varied in random order over three levels of positive end-expiratory pressure (PEEP), respiratory rate (RR), and plateau pressure minus PEEP (Delta). Dependence of the amplitude of PaO2 oscillations on PEEP, RR, and Delta was modeled by multiple linear regression. Before lavage, arterial PO2 oscillations varied from 3 to 22 mm Hg. After lavage, arterial PO2 oscillations varied from 5 to 439 mm Hg. Response surfaces showed markedly nonlinear dependence of amplitude on PEEP, RR, and Delta. The large PaO2 oscillations observed provide evidence for cyclic recruitment in this model of lung injury. The important effect of RR on the magnitude of PaO2 oscillations suggests that the static behavior of atelectasis cannot be accurately extrapolated to predict dynamic behavior at realistic breathing frequencies.

  6. FEA of CMUTs Suitable for Wide Gas Pressure Range Applications.

    PubMed

    Ho, Min-Chieh; Kupnik, Mario; Khuri-Yakub, Butrus T

    2010-10-11

    The ability of ultrasound transducers to operate over a wide and varying pressure range is essential in applications such as ultrasonic flow metering (UFM) of flare gas. We propose a new operational mode for capacitive micromachined ultrasonic transducers (CMUTs), in which the plate is in permanent contact with the bottom of the cavity, even at zero DC bias and 1 atm pressure. Finite element analysis (FEA) software was used to investigate the performance of these CMUTs within the pressure range of 1 to 20 atm. First, we performed a static analysis to determine the plate deflection and, thus, the gap height. Further, from the static analysis, we obtained the static and free capacitances for calculating the coupling efficiency, and a modal analysis identified possible design geometries for frequencies lower than ~ 300 kHz. Our calculations show that conventionally operated CMUTs have huge changes in static operational point at different pressures, while our proposed mode exhibits an acceptable frequency range (73 - 340 kHz) over 1 - 20 atm pressure and an improved coupling efficiency at lower dc bias voltages. A donut shape partial electrode further allows us to tune the coupling efficiency, which translates into a better performance, especially at the higher pressure range. FEA shows that our proposed operation mode is a promising solution for flare gas metering applications.

  7. Quantitative Micro-Raman Spectroscopy for Partial Pressure Measurement in Small Volumes.

    PubMed

    Karlen, Sylvain; Gobet, Jean; Overstolz, Thomas; Haesler, Jacques; Lecomte, Steve

    2017-01-01

    We demonstrate the quantitative capabilities of Raman confocal microscopy as a nondestructive method to measure the partial pressure of molecular gases in mm(3) range sealed volume having an optical access. Thanks to a calibration procedure, we apply this technique for the characterization of the absolute nitrogen partial pressure inside buffered micro electromechanical system (MEMS) atomic vapor cells developed for atomic clocks. Our results are compared with measurements obtained by rubidium hyperfine frequency spectroscopy and a good agreement is demonstrated between the two methods, with a three-sigma detection limit below 10 mbar for a 1 h integration time, using a 33 mW 532 nm excitation laser. These results prove the potential of confocal micro-Raman spectroscopy as a simple and nondestructive method for small-scale pressure measurements.

  8. Critical heat flux on micro-structured zircaloy surfaces for flow boiling of water at low pressures

    SciTech Connect

    Haas, C.; Miassoedov, A.; Schulenberg, T.; Wetzel, T.

    2012-07-01

    The influence of surface structure on critical heat flux for flow boiling of water was investigated for Zircaloy tubes in a vertical annular test section. The objectives were to find suitable surface modification processes for Zircaloy tubes and to test their critical heat flux performance in comparison to the smooth tube. Surface structures with micro-channels, porous layer, oxidized layer, and elevations in micro- and nano-scale were produced on a section of a Zircaloy cladding tube. These modified tubes were tested in an internally heated vertical annulus with a heated length of 326 mm and an inner and outer diameter of 9.5 and 18 mm. The experiments were performed with mass fluxes of 250 and 400 kg/(m{sup 2}s), outlet pressures between 120 and 300 kPa, and constant inlet subcooling enthalpy of 167 kJ/kg. Only a small influence of modified surface structures on critical heat flux was observed for the pressure of 120 kPa in the present test section geometry. However, with increasing pressure the critical heat flux could increase up to 29% using the surface structured tubes with micro-channels, porous and oxidized layers. Capillary effects and increased nucleation site density are assumed to improve the critical heat flux performance. (authors)

  9. Host range of the potential biopesticide Pea Albumin 1b (PA1b) is limited to insects.

    PubMed

    Rahioui, Isabelle; Eyraud, Vanessa; Karaki, Lamis; Sasse, Florenz; Carre-Pierrat, Maïté; Qin, An; Zheng, Ming H; Toepfer, Stefan; Sivignon, Catherine; Royer, Corinne; Da Silva, Pedro; Gressent, Frédéric

    2014-10-01

    The Pea Albumin 1 subunit b (PA1b) peptide is an entomotoxin extracted from legume seeds with lethal activity towards several insect pests. Its toxic activity occurs after the perception of PA1b by a plasmalemmic proton pump (V-ATPase) in the insects. Assays revealed that PA1b showed no activity towards mammalian cells displaying high V-ATPase activity. Similarly, PA1b displayed no binding activity and no biological activity towards other non-insect organisms. We demonstrate here that binding to labelled PA1b was found in all the insect families tested, regardless of the sensitivity or insensitivity of the individual species. The coleopteran Bruchidae, which are mainly legume seed pests, were found to be fully resistant. A number of insect species were seen to be insensitive to the toxin although they exhibited binding activity for the labelled PA1b. The fruit fly, Drosophila melanogaster (Diptera), was generally insensitive when maintained on an agar diet, but the fly appeared to be sensitive to PA1b in bioassays using a different diet. In conclusion, the PA1b toxin provides legumes with a major source of resistance to insects, and insects feeding on legume seeds need to overcome this plant resistance by disrupting the PA1b - V-ATPase interaction.

  10. Wide vacuum pressure range monitoring by Pirani SAW sensor.

    PubMed

    Nicolay, Pascal; Elmazria, Omar; Sarry, Frederic; Bouvot, Laurent; Kambara, Hisanori; Singh, Kanwar J; Alnot, Patrick

    2010-03-01

    A new kind of surface acoustic wave (SAW) sensor has been developed to measure sub-atmospheric pressure below 100 mtorr with accuracy better than 0.1 mtorr. It provides an efficient measuring solution in the pressure range inaccessible in past by conventional diaphragm-based SAW sensors. Indeed, because of the small bending force in lower pressure and limited sensitivity, diaphragm-based SAW sensors are only suited to monitor relatively high pressure with a precision hardly better than 0.5 torr. To reach precision level better than 1 mtorr at sub-atmospheric pressure for vacuum technology applications, a radically different SAW-based solution is necessary. Our device aims to measure sub-atmospheric pressure less than 100 mtorr with a threshold resolution better than 0.1 mtorr. The concept is similar to the one used by Pirani pressure gauges. However, it is claimed that a heated and suspended SAW device should have better sensitivity. A theoretical model based on the basic concepts of gas kinetic theory and thermodynamics is presented. The validity of the model is checked by comparison between theoretical and experimental results.

  11. [Blood pressure findings in Spanish dyslipidemic primary-care patients. LIPICAP-PA Study].

    PubMed

    Rodríguez-Roca, Gustavo C; Alonso-Moreno, Francisco J; Barrios, Vivencio; Llisterri, José L; Lou, Salvador; Matalí, Arantxa; Banegas, José R

    2007-08-01

    Despite the well-known significant relationship between blood pressure and cardiovascular mortality, few data are available on the blood pressure characteristics of dyslipidemic patients. The aims of this study were to determine the blood pressure characteristics of dyslipidemic patients being treated in primary care, and to identify factors associated with poor blood pressure control. This multicentre cross-sectional study involved patients of both sexes aged > or =18 years who were diagnosed with dyslipidemia (i.e., hypercholesterolemia, hypertriglyceridemia, mixed dyslipidemia, or a low high-density lipoprotein cholesterol level) in the 17 Spanish autonomous regions. Blood pressure was measured according to standard procedures, and was considered well-controlled if it was <140/90 mm Hg (or <130/80 mm Hg in patients with diabetes, nephropathy or cardiovascular disease). In total, 7054 patients were studied (mean age 61.3 [11.2] years, 50.8% male). Mean systolic and diastolic blood pressures were 134.6 [14.2]/79.8 [8.9] mm Hg, with significant differences (P< .001) between hypertensives (140.8 [14.6]/82.8 [9.0] mmHg) and normotensives (128.5 [10.7]/76.9 [7.7] mm Hg). Good blood pressure control was observed in 47.4% (95% confidence interval, 46.3-48.5%) of subjects overall, in 29.3% of hypertensives, and in 12.8% of hypertensive diabetics. Poor control was associated with an increased cardiovascular disease risk (hazard ratio [HR]=2.89), poor control of low-density lipoprotein cholesterol (HR=1.43), a higher body mass index (HR=1.06), and older age (HR=1.02). Fewer than half of dyslipidemic primary-care patients in Spain had good blood pressure control. Poor control was associated, in particular, with increased cardiovascular risk and poor control of the low-density lipoprotein cholesterol level.

  12. Measurement of interlayer pressure in micro-clearance based on photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Yi, Zhang; Zhi, Zhuang; Minghai, Li; Shaoquan, Hu; Rong, Zhang; Yang, Minghong

    2017-06-01

    A novel measurement method for interlayer pressure in micro-clearance based on photonic crystal fiber is proposed and experimentally demonstrated. A sensor with a height of only 230 µm was fabricated using polarization-maintaining photonic crystal fiber with higher birefringence. Experimental results show that the linearity and repeatability of the proposed sensor are 1.61%FS and 0.55%FS respectively. The sensor covered by a flimsy cushion material exhibits a large bearing pressure capability of 18.2 MPa, and the work range extends to 5 MPa. Such measurement technology could be very promising for mechanical characterization in narrow space.

  13. Aerial ultrasonic micro Doppler sonar detection range in outdoor environments.

    PubMed

    Bradley, Marshall; Sabatier, James M

    2012-03-01

    Current research demonstrates that micro Doppler sonar has the capability to uniquely identify the presence of a moving human, making it an attractive component in surveillance systems for border security applications. Primary environmental factors that limit sonar performance are two-way spreading losses, ultrasonic absorption, and backscattered energy from the ground that appears at zero Doppler shift in the sonar signal processor. Spectral leakage from the backscatter component has a significant effect on sonar performance for slow moving targets. Sonar performance is shown to rapidly decay as the sensor is moved closer to the ground due to increasing surface backscatter levels.

  14. Pressure drop characteristics of cryogenic mixed refrigerant at macro and micro channel heat exchangers

    NASA Astrophysics Data System (ADS)

    Baek, Seungwhan; Jeong, Sangkwon; Hwang, Gyuwan

    2012-12-01

    Mixed Refrigerant-Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. The temperature glide effect is one of the major features of using mixed refrigerants since a recuperative heat exchanger in a MR-JT refrigerator is utilized for mostly two-phase flow. Although a pressure drop estimation for a multi-phase and multi-component fluid in the cryogenic temperature range is necessarily required in MR-JT refrigerator heat exchanger designs, it has been rarely discussed so far. In this paper, macro heat exchangers and micro heat exchangers are compared in order to investigate the pressure drop characteristics in the experimental MR-JT refrigerator operation. The tube in tube heat exchanger (TTHE) is a well-known macro-channel heat exchanger in MR-JT refrigeration. Printed Circuit Heat Exchangers (PCHEs) have been developed as a compact heat exchanger with micro size channels. Several two-phase pressure drop correlations are examined to discuss the experimental pressure measurement results. The result of this paper shows that cryogenic mixed refrigerant pressure drop can be estimated with conventional two-phase pressure drop correlations if an appropriate flow pattern is identified.

  15. Quantification of the Effect of Pressure Wire Drift on the Diagnostic Performance of Fractional Flow Reserve, Instantaneous Wave-Free Ratio, and Whole-Cycle Pd/Pa

    PubMed Central

    Ahmad, Yousif; Shun-Shin, Matthew J.; Nijjer, Sukhjinder; Petraco, Ricardo; Al-Lamee, Rasha; Mayet, Jamil; Francis, Darrel P.; Sen, Sayan; Davies, Justin E.

    2016-01-01

    Background— Small drifts in intracoronary pressure measurements (±2 mm Hg) can affect stenosis categorization using pressure indices. This has not previously been assessed for fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), and whole-cycle distal pressure/proximal pressure (Pd/Pa) indices. Methods and Results—Four hundred forty-seven stenoses were assessed with FFR, iFR, and whole-cycle Pd/Pa. Cut point values for significance were predefined as ≤0.8, <0.90, and <0.93, respectively. Pressure wire drift was simulated by offsetting the distal coronary pressure trace by ±2 mm Hg. FFR, iFR, and whole-cycle Pd/Pa indices were recalculated and stenosis misclassification quantified. Median (±median absolute deviation) values for FFR, iFR, and whole-cycle Pd/Pa were 0.81 (±0.11), 0.90 (±0.07), and 0.93 (±0.06), respectively. For the cut point of FFR, iFR, and whole-cycle Pd/Pa, 34.6% (155), 50.1% (224), and 62.2% (278) of values, respectively, lay within ±0.05 U. With ±2 mm Hg pressure wire drift, 21% (94), 25% (110), and 33% (148) of the study population were misclassified with FFR, iFR, and whole-cycle Pd/Pa, respectively. Both FFR and iFR had significantly lower misclassification than whole-cycle Pd/Pa (P<0.001). There was no statistically significant difference between the diagnostic performance of FFR and iFR (P=0.125). Conclusions— In a substantial proportion of cases, small amounts of pressure wire drift are enough to cause stenoses to change classification. Whole-cycle Pd/Pa is more vulnerable to such reclassification than FFR and iFR. PMID:27076571

  16. Fiber Bragg grating sensors written by femtosecond laser pulses in micro-structured fiber for downhole pressure monitoring

    NASA Astrophysics Data System (ADS)

    Huang, J.-Y.; Van Roosbroeck, J.; Bueno Martinez, A.; Geernaert, T.; Berghmans, F.; Caucheteur, C.; Van Hoe, B.; Lindner, E.; Vlekken, J.

    2017-04-01

    In this paper, we demonstrate that femtosecond laser pulse written fiber Bragg gratings (FBGs) fabricated in specialty highly birefringent micro-structured optical fiber (MSF) can be used for high pressure and high temperature monitoring in downhole applications. The design of the micro-structure allows encoding the pressure information into the spectral separation between the two Bragg peaks reflected by the obtained MS-FBG. We obtained a differential pressure sensitivity of 3.30 pm/bar over a pressure range from atmospheric up to 1400 bar and at temperatures between 40 °C and 290 °C. Owing to the negligible differential pressure-temperature cross-sensitivity of 6.06E-3 bar/°C, the proposed MSFBG sensor is an ideal candidate for pressure monitoring in the presence of high temperature transients.

  17. Ultra-low sensitivity to temperature low-cost optical fiber Fabry-Perot micro pressure sensor with a chitosan diaphragm

    NASA Astrophysics Data System (ADS)

    Wang, Wenhua; Li, Sidong; Wen, Lili

    2013-11-01

    In this paper, a low-cost CDEFPI (chitosan diaphragm-based extrinsic Fabry-Perot interferometer) micro pressure sensor with high sensitivity and ultra-low temperature dependence is proposed. The chitosan diaphragm is achieved through crosslinking method via glutaraldehyde which reduces extremely the water swelling property of chitosan and improves greatly the performance of sensor. A vent hole leaving during laser heating fusion bonding process guarantees the ultra-low temperature sensitivity of the sensor. The CDEFPI pressure sensor with a sensitivity of 25.65 nm/kPa (176.86 nm/psi), a resolution of 7.8 Pa (0.001 psi), temperature sensitivity of 0.015 nm/°C, and a thermal induced pressure measurement error limited within 0.0005 kPa/°C (0.00007 psi/°C) has been demonstrated.

  18. Initiation of delayed hydride cracking in zirconium-niobium micro pressure tubes

    NASA Astrophysics Data System (ADS)

    Sundaramoorthy, Ravi Kumar

    Pressure tubes pick up hydrogen while they are in service within CANDU reactors. Sufficiently high hydrogen concentration can lead to hydride precipitation during reactor shutdown/repair at flaws, resulting in the potential for eventual rupture of the pressure tubes by a process called Delayed Hydride Cracking (DHC). The threshold stress intensity factor (KIH) below which the cracks will not grow by delayed hydride cracking of Zr-2.5Nb micro pressure tubes (MPTs) has been determined using a load increasing mode (LIM) method at different temperatures. MPTs have been used to allow easy study of the impact of properties like texture and grain size on DHC. Previous studies on MPTs have focused on creep and effects of stress on hydride orientation; here the use of MPTs for DHC studies is confirmed for the first time. Micro pressure tube samples were hydrided to a target hydrogen content of 100 ppm using an electrolytic method. For DHC testing, 3 mm thick half ring samples were cut out from the tubes using Electrical Discharge Machining (EDM) with a notch at the center. A sharp notch with a root radius of 15 microm was introduced by broaching to facilitate crack initiation. The direct current potential drop method was used to monitor crack growth during the DHC tests. For the temperature range tested the threshold stress intensity factors for the micro pressure tube used were found to be 6.5--10.5 MPa.m 1/2 with the value increasing with increasing temperature. The average DHC velocities obtained for the three different test temperatures 180, 230 and 250°C were 2.64, 10.87 and 8.45 x 10-8 m/s, respectively. The DHC data obtained from the MPTs are comparable to the data published in the literature for full sized CANDU pressure tubes.

  19. Dietary phosphorus and blood pressure: international study of macro- and micro-nutrients and blood pressure.

    PubMed

    Elliott, Paul; Kesteloot, Hugo; Appel, Lawrence J; Dyer, Alan R; Ueshima, Hirotsugu; Chan, Queenie; Brown, Ian J; Zhao, Liancheng; Stamler, Jeremiah

    2008-03-01

    Raised blood pressure is a leading cause of morbidity and mortality worldwide; improved nutritional approaches to population-wide prevention are required. Few data are available on dietary phosphorus and blood pressure and none are available on possible combined effects of phosphorus, magnesium, and calcium on blood pressure. The International Study of Macro- and Micro-Nutrients and Blood Pressure is a cross-sectional epidemiologic study of 4680 men and women ages 40 to 59 from 17 population samples in Japan, China, United Kingdom, and United States. Blood pressure was measured 8 times at 4 visits. Dietary intakes were obtained from four 24-hour recalls plus data on supplement use. Dietary phosphorus was inversely associated with blood pressure in a series of predefined multiple regression models, with the successive addition of potential confounders, both nondietary and dietary. Estimated blood pressure differences per 232 mg/1000 kcal (2 SD) of higher dietary phosphorus were -1.1 to -2.3 mm Hg systolic/-0.6 to -1.5 mm Hg diastolic (n=4680) and -1.6 to -3.5 mm Hg systolic/-0.8 to -1.8 mm Hg diastolic for 2238 "nonintervened" individuals, ie, those without special diet/nutritional supplements or diagnosis/treatment for cardiovascular disease or diabetes. Dietary calcium and magnesium, correlated with phosphorus (partial r=0.71 and r=0.68), were inversely associated with blood pressure. Blood pressures were lower by 1.9 to 4.2 mm Hg systolic/1.2 to 2.4 mm Hg diastolic for people with intakes above versus below country-specific medians for all 3 of the minerals. These results indicate the potential for increased phosphorus/mineral intake to lower blood pressure as part of the recommendations for healthier eating patterns for the prevention and control of prehypertension and hypertension.

  20. Enhanced dynamic range fringe projection for micro-structure characterization

    NASA Astrophysics Data System (ADS)

    Samara, Ayman Mohammad

    We present a solution for one of the main limitations in classical interferometry and fringe projection, which is the dynamic range limitation. The technique is based on real time inverse fringe projection to enhance the dynamic range and increase the vertical resolution without the need of prior information about the test object or the system parameters. The object's form optical path difference map is first measured, and then used to generate inverse fringes to optically filter the low spatial frequency form. The surface finish can then be measured without the impact of the form. A stereo microscope-based fringe projection system was designed, constructed, and used to illustrate the technique. The system was also used to characterize solder bumps with an uncertainty of approximately 10%. Individual solder bumps were also characterized using Zygo's NewView(TM) scanning white light interferometer (SWLI), and the results were compared to measurements on Intel's bump metrology tool. The results show that the SWLI has the lowest uncertainty and maximum repeatability but the lowest measurement speed. Intel's tool has a repeatability of approximately 1% and a measurement speed of about 10 minutes per 100,000 bumps, making it suitable for high volume process control.

  1. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Gauges and vapor return for cargo vapor pressures... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia). When table 1 references...

  2. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Gauges and vapor return for cargo vapor pressures... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia). When table 1 references...

  3. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Gauges and vapor return for cargo vapor pressures... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia). When table 1 references...

  4. Fabrication and Structural Design of Micro Pressure Sensors for Tire Pressure Measurement Systems (TPMS).

    PubMed

    Tian, Bian; Zhao, Yulong; Jiang, Zhuangde; Zhang, Ling; Liao, Nansheng; Liu, Yuanhao; Meng, Chao

    2009-01-01

    In this paper we describe the design and testing of a micro piezoresistive pressure sensor for a Tire Pressure Measurement System (TPMS) which has the advantages of a minimized structure, high sensitivity, linearity and accuracy. Through analysis of the stress distribution of the diaphragm using the ANSYS software, a model of the structure was established. The fabrication on a single silicon substrate utilizes the technologies of anisotropic chemical etching and packaging through glass anodic bonding. The performance of this type of piezoresistive sensor, including size, sensitivity, and long-term stability, were investigated. The results indicate that the accuracy is 0.5% FS, therefore this design meets the requirements for a TPMS, and not only has a smaller size and simplicity of preparation, but also has high sensitivity and accuracy.

  5. Fabrication and Structural Design of Micro Pressure Sensors for Tire Pressure Measurement Systems (TPMS)

    PubMed Central

    Tian, Bian; Zhao, Yulong; Jiang, Zhuangde; Zhang, Ling; Liao, Nansheng; Liu, Yuanhao; Meng, Chao

    2009-01-01

    In this paper we describe the design and testing of a micro piezoresistive pressure sensor for a Tire Pressure Measurement System (TPMS) which has the advantages of a minimized structure, high sensitivity, linearity and accuracy. Through analysis of the stress distribution of the diaphragm using the ANSYS software, a model of the structure was established. The fabrication on a single silicon substrate utilizes the technologies of anisotropic chemical etching and packaging through glass anodic bonding. The performance of this type of piezoresistive sensor, including size, sensitivity, and long-term stability, were investigated. The results indicate that the accuracy is 0.5% FS, therefore this design meets the requirements for a TPMS, and not only has a smaller size and simplicity of preparation, but also has high sensitivity and accuracy. PMID:22573960

  6. Long-range scaling behaviours of human colonic pressure activities

    NASA Astrophysics Data System (ADS)

    Yan, Rongguo; Yan, Guozheng; Zhang, Wenqiang; Wang, Long

    2008-11-01

    The long-range scaling behaviours of human colonic pressure activities under normal physiological conditions are studied by using the method of detrended fluctuation analysis (DFA). The DFA is an effective period representation with a single quantitative scaling exponent α to accurately quantify long-range correlations naturally presented in a complex non-stationary time series. The method shows that the colonic activities of the healthy subjects exhibit long-range power-law correlations; however such correlations either will be destroyed if we randomly shuffle the original data or will cease to be of a power-law form if we chop some high-amplitude spikes off. These facts indicate that the colonic tissue or enteric nervous system (ENS) with a good functional motility has a good memory to its past behaviours and generates well-organized colonic spikes; however such good memory becomes too long to be remembered for the colonic activity of the slow transit constipation (STC) patient and colonic dysmotility occurs.

  7. A high performance micro-pressure sensor based on a double-ended quartz tuning fork and silicon diaphragm in atmospheric packaging

    NASA Astrophysics Data System (ADS)

    Cheng, Rongjun; Li, Cun; Zhao, Yulong; Li, Bo; Tian, Bian

    2015-06-01

    A resonant micro-pressure sensor based on a double-ended quartz tuning fork (DEQTF) and bossed silicon diaphragm in atmospheric packaging is presented. To achieve vacuum-free packaging with a high quality factor, the DEQTF is designed to resonate in an anti-phase vibration mode in a plane that is under the effect of slide-film damping. The feasibility is demonstrated by theoretical analysis and a finite element simulation. The dimensions of the DEQTF and diaphragm are optimized in accordance with the principles of improving sensitivity and minimizing energy dissipation. The sensor chip is fabricated using quartz and silicon micromachining technologies, and simply packaged in a stainless steel shell with standard atmosphere. The experimental setup is established for the calibration, where an additional sensor prototype without a pressure port is introduced as a frequency reference. By detecting the frequency difference of the tested sensor and reference sensor, the influences of environmental factors such as temperature and shocks on measuring accuracy are eliminated effectively. Under the action of a self-excitation circuit, static performance is obtained. The sensitivity of the sensor is 299 kHz kPa-1 in the operating range of 0-10 kPa at room temperature. Testing results shows a nonlinearity of 0.0278%FS, a hysteresis of 0.0207%FS and a repeatability of 0.0375%FS. The results indicate that the proposed sensor has favorable features, which provides a cost-effective and high-performance approach for low pressure measurement.

  8. Outcomes of Patients Requiring Blood Pressure Control Before Thrombolysis with tPA for Acute Ischemic Stroke

    PubMed Central

    Darger, Bryan; Gonzales, Nicole; Banuelos, Rosa C.; Peng, Hui; Radecki, Ryan P.; Doshi, Pratik B.

    2015-01-01

    Introduction The purpose of this study was to assess safety and efficacy of thrombolysis in the setting of aggressive blood pressure (BP) control as it compares to standard BP control or no BP control prior to thrombolysis. Methods We performed a retrospective review of patients treated with tissue plasminogen activator (tPA) for acute ischemic stroke (AIS) between 2004–2011. We compared the outcomes of patients treated with tPA for AIS who required aggressive BP control prior to thrombolysis to those requiring standard or no BP control prior to thrombolysis. The primary outcome of interest was safety, defined by all grades of hemorrhagic transformation and neurologic deterioration. The secondary outcome was efficacy, determined by functional status at discharge, and in-hospital deaths. Results Of 427 patients included in the analysis, 89 received aggressive BP control prior to thrombolysis, 65 received standard BP control, and 273 required no BP control prior to thrombolysis. Patients requiring BP control had more severe strokes, with median arrival National Institutes of Health Stroke Scale of 10 (IQR [6–17]) in patients not requiring BP control versus 11 (IQR [5–16]) and 13 (IQR [7–20]) in patients requiring standard and aggressive BP lowering therapies, respectively (p=0.048). In a multiple logistic regression model adjusting for baseline differences, there were no statistically significant differences in adverse events between the three groups (P>0.10). Conclusion We observed no association between BP control and adverse outcomes in ischemic stroke patients undergoing thrombolysis. However, additional study is necessary to confirm or refute the safety of aggressive BP control prior to thrombolysis. PMID:26759644

  9. Geometry optimization for micro-pressure sensor considering dynamic interference

    SciTech Connect

    Yu, Zhongliang; Zhao, Yulong Li, Lili; Tian, Bian; Li, Cun

    2014-09-15

    Presented is the geometry optimization for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. Optimization by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and dynamic conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz{sup 1/4}. The favorable overall performances enable the sensor more suitable for altimetry.

  10. High sensitive/wide dynamic range, field emission pressure sensor based on fully embedded CNTs

    NASA Astrophysics Data System (ADS)

    Taak, S.; Rajabali, S.; Darbari, S.; Mohajerzadeh, S.

    2014-01-01

    The formation of high sensitivity-wide dynamic range field emission pressure sensors based on carbon nanotubes (CNTs) is reported. In this work, CNTs are grown inside an array of micromachined holes in order to ensure a high sensitivity and a wide dynamic range by allowing anode-cathode proximity while preventing anode-cathode direct contact simultaneously. External pressure is applied to a Si-based flexible anode, which results in consequent variations in emission current, due to electric field changes. Microcavities in this structure have been formed by a Si deep vertical etching process, while the CNTs have been grown by direct current plasma-enhanced chemical vapour deposition. Also, it is demonstrated that a similar fabrication process can be applied to implement a device with an electrically controllable emission current. A high sensitivity of 1.5-13.7 µA kPa-1 (with Vanode/cathode < 100 V) within a dynamic range from around 0.1 to 1 GPa, is measured in this experiment.

  11. Loss or Inhibition of uPA or MMP-9 Attenuates LV Remodeling and Dysfunction after Acute Pressure Overload in Mice

    PubMed Central

    Heymans, Stephane; Lupu, Florea; Terclavers, Sven; Vanwetswinkel, Bjorn; Herbert, Jean-Marc; Baker, Andrew; Collen, Desire; Carmeliet, Peter; Moons, Lieve

    2005-01-01

    Left ventricular (LV) hypertrophy is a natural response of the heart to increased pressure loading, but accompanying fibrosis and dilatation may result in irreversible life-threatening heart failure. Matrix metalloproteinases (MMPs) have been invoked in various cardiac diseases, however, direct genetic evidence for a role of the plasminogen activator (PA) and MMP systems in pressure overload-induced LV hypertrophy and in heart failure is lacking. Therefore, the consequences of transverse aortic banding (TAB) were analyzed in mice lacking tissue-type PA (t-PA−/−), urokinase-type PA (u-PA−/−), or gelatinase-B (MMP-9−/−), and in wild-type (WT) mice after adenoviral gene transfer of the PA-inhibitor PAI-1 or the MMP-inhibitor TIMP-1. TAB elevated LV pressure comparably in all genotypes. In WT and t-PA−/− mice, cardiomyocyte hypertrophy was associated with myocardial fibrosis, LV dilatation and dysfunction, and pump failure after 7 weeks. In contrast, in u-PA−/− mice or in WT mice after PAI-1- and TIMP-1-gene transfer, cardiomyocyte hypertrophy was moderate and only minimally associated with cardiac fibrosis and LV dilatation, resulting in better preservation of pump function. Deficiency of MMP-9 had an intermediate effect. These findings suggest that the use of u-PA- or MMP-inhibitors might preserve cardiac pump function in LV pressure overloading. PMID:15631996

  12. Noninvasive Measurement of the Pressure Distribution in a Deformable Micro-Channel

    NASA Astrophysics Data System (ADS)

    Ozsun, Ozgur; Yakhot, Victor; Ekinci, Kamil L.

    2013-11-01

    Direct and noninvasive measurement of the pressure drop in test sections of a rigid micro-channel is a challenging task. In a micro-channel with compliant walls, however, it is possible to determine the pressure field under flow from the local deflection of the channel walls. Here, we present a robust analytical approach for determining the pressure distribution in a deformable micro-channel under flow. In this method, we first measure the channel deflection profile as a function of applied hydrostatic pressure; this initial measurement provides the constitutive curves for the deformable channel. We then match the deflection profile under flow to the constitutive curves, obtaining the hydrodynamic pressure distribution. We have tested and validated the developed mapping on planar micro-fluidic channels. This method remains accurate in a broad parameter space, and can find possible applications in microfluidics and for characterizing biological flows. We acknowledge generous support from the US NSF through Grant No. CMMI-0970071.

  13. Introducing bio- and micro-technology into undergraduate thermal-fluids courses: investigating pipe pressure loss via atomic force microscopy.

    PubMed

    Müller, Marcus; Traum, Matthew J

    2012-01-01

    To introduce bio- and micro-technologies into general undergraduate thermal-fluids classes, a hands-on interdisciplinary in-class demonstration is described that juxtaposes classical pressure loss pipe flow experiments against a modern micro-characterization technique, AFM profilometry. Both approaches measure surface roughness and can segue into classroom discussions related to material selection and design of bio-medical devices to handle biological fluids such as blood. Appealing to the range of engineering students populating a general thermal-fluids course, a variety of pipe/hose/tube materials representing a spectrum of disciplines can be tested using both techniques. This in-class demonstration relies on technical content already available in standard thermal-fluids textbooks, provides experimental juxtaposition between classical and micro-technology-enabled approaches to the same experiment, and can be taught by personnel with no specialized micro- or bio-technology expertise.

  14. Note: A micro-perfusion system for use during real-time physiological studies under high pressure.

    PubMed

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  15. Note: A micro-perfusion system for use during real-time physiological studies under high pressure

    NASA Astrophysics Data System (ADS)

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  16. SUPPLEMENTARY COMPARISON: Final report on supplementary comparison APMP.M.P-S2 (bilateral comparison) at a nominal pressure of 0.05 Pa

    NASA Astrophysics Data System (ADS)

    Mohan, Pardeep; Abbott, Patrick J.

    2008-01-01

    A supplementary bilateral comparison was carried out to compare two different pressure standards at a nominal pressure of 0.05 Pa. The two standards used different principles for generating the nominal pressure; one based on the static expansion method (NPL, India), and the other based on the orifice flow or dynamic expansion method (NIST, USA). The transfer standard consisted of a pair of spinning rotor gauges whose accommodation coefficients were measured at a nominal pressure of 0.05 Pa at the two laboratories. The nominal pressure value for the comparison was chosen because (i) it can be easily generated by the respective standards with high accuracy and (ii) it had not been covered in the earlier two key comparisons, namely, CCM.P-K3 and CCM.P-K4, which the two NMIs had participated in. NPLI served as the pilot lab, and provided the stainless steel rotors; each lab used its own thimbles and electronics. The rotors were hand-carried from NPLI to NIST at atmospheric pressure in small, insulation-packed glass vials to prevent the rotors from moving during transit; otherwise no special transit precautions were taken. The pressure value of 0.05 Pa generated by the NPLI and NIST showed good agreement within their combined uncertainties, proving thereby that the two standards were equivalent to each other for the pressure of 0.05 Pa. Main text. To reach the main text of this Paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the APMP, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  17. Capacitance variation measurement method with a continuously variable measuring range for a micro-capacitance sensor

    NASA Astrophysics Data System (ADS)

    Lü, Xiaozhou; Xie, Kai; Xue, Dongfeng; Zhang, Feng; Qi, Liang; Tao, Yebo; Li, Teng; Bao, Weimin; Wang, Songlin; Li, Xiaoping; Chen, Renjie

    2017-10-01

    Micro-capacitance sensors are widely applied in industrial applications for the measurement of mechanical variations. The measurement accuracy of micro-capacitance sensors is highly dependent on the capacitance measurement circuit. To overcome the inability of commonly used methods to directly measure capacitance variation and deal with the conflict between the measurement range and accuracy, this paper presents a capacitance variation measurement method which is able to measure the output capacitance variation (relative value) of the micro-capacitance sensor with a continuously variable measuring range. We present the principles and analyze the non-ideal factors affecting this method. To implement the method, we developed a capacitance variation measurement circuit and carried out experiments to test the circuit. The result shows that the circuit is able to measure a capacitance variation range of 0–700 pF linearly with a maximum relative accuracy of 0.05% and a capacitance range of 0–2 nF (with a baseline capacitance of 1 nF) with a constant resolution of 0.03%. The circuit is proposed as a new method to measure capacitance and is expected to have applications in micro-capacitance sensors for measuring capacitance variation with a continuously variable measuring range.

  18. PA28gamma emerges as a novel functional target of tumour suppressor microRNA-7 in non-small-cell lung cancer

    PubMed Central

    Xiong, S; Zheng, Y; Jiang, P; Liu, R; Liu, X; Qian, J; Gu, J; Chang, L; Ge, D; Chu, Y

    2014-01-01

    Background: MicroRNA-7 (miR-7) has been reported to be a tumour suppressor gene. However, whether it has a role in the growth of non-small-cell lung cancer (NSCLC) and what is its target involved in the tumour growth is still under investigation. Methods: NSCLC tissue sample, NSCLC cell lines and tissue microarray were investigated in this study. Total RNA, miRNA and protein were used for RT-PCR and western blot analysis. Immunohistochemistry was performed in tissues microarray. Cell culture and intervention experiments were performed in vitro and in vivo. Bioinformatics prediction, western blot and luciferase assay were identified the target of miR-7. Results: In this study, we found that the expression of miR-7 was significantly downregulated not only in NSCLC cell lines, but also in human NSCLC tissues compared with the matched adjacent tissues. Restoration of its expression through miR-7 mimics in A549 and H1299 NSCLC cells inhibited cell proliferation, colony formation, and cell-cycle progression in vitro. More importantly, the tumorigenicity in nude mice was reduced after administration of miR-7 in vivo. In advance, through bioinformatic analysis, luciferase assay and western blot, we identified a novel target of miR-7, PA28gamma (a proteasome activator) to be enrolled in the regulation with tumour. PA28gamma mRNA and protein levels are markedly upregulated in NSCLC cell lines and tumour samples, exhibiting a strong inverse relation with that of miR-7. In addition, knockdown of PA28gamma induced similar effects as overexpression of miR-7 in NSCLC cells. Furthermore, miR-7 overexpression or silencing of PA28gamma reduced the cyclinD1 expression at mRNA and protein level in NSCLC cell lines. Conclusion: All these findings strongly imply that the overexpression of PA28gamma resulted from miR-7 downexpression in NSCLC has an important role in promoting cancer cell progress and consequently results in NSCLC growth. Thus, strategies targeting PA28gamma and/or miR-7

  19. The electron spectro-microscopy beamline at National Synchrotron Light Source II: A wide photon energy range, micro-focusing beamlinefor photoelectron spectro-microscopies

    SciTech Connect

    Reininger R.; Hulbert L.; Johnson P.D.; Sadowski, J.T.; Starr, D.E.; Chubar, O.; Valla, T.; Vescovo, E.

    2012-02-13

    A comprehensive optical design for a high-resolution, high-flux, wide-energy range, micro-focused beamline working in the vacuum ultraviolet and soft x-ray photon energy range is proposed. The beamline is to provide monochromatic radiation to three photoelectron microscopes: a full-field x-ray photoelectron emission microscope and two scanning instruments, one dedicated to angle resolved photoemission spectroscopy ({micro}-ARPES) and one for ambient pressure x-ray photoelectron spectroscopy and scanning photoelectron microscopy (AP-XPS/SPEM). Microfocusing is achieved with state of the art elliptical cylinders, obtaining a spot size of 1 {micro}m for ARPES and 0.5 {micro}m for AP-XPS/SPEM. A detailed ray tracing analysis quantitatively evaluates the overall beamline performances.

  20. Experimental study of PDMS mechanical properties for the optimization of polymer based flexible pressure micro-sensors

    NASA Astrophysics Data System (ADS)

    Dinh, T. H. N.; Martincic, E.; Dufour-Gergam, E.; Joubert, P.-Y.

    2016-10-01

    This paper reports on the optimization of flexible PDMS-based normal pressure capacitive micro-sensors dedicated to wearable applications. The deformation under a normal force of PDMS thin films of thicknesses ranging from 40 μm to 10 mm is firstly experimentally studied. This study points out that for capacitive micro-sensors using bulky PDMS thin films as deformable dielectric material, the sensitivity to an applied normal load can be optimized thanks to an adequate choice of the so-called form ratio of the involved PDMS thin film. Indeed, for capacitive micro-sensors exhibiting 9 mm2 electrodes, the capacitance change under a 6 N load can be adjusted from a few percent up to over 35% according to the choice of the load-free thickness of the used PDMS film. These results have been validated thanks to electromechanical characterizations carried out on two flexible PDMS based capacitive normal pressure micro-sensor samples fabricated with two different thicknesses. The obtained results open the way to the enhanced design of PDMS based pressure sensors dedicated to wearable and medical applications. Further works will extend this study to a wider range of sensor dimensions, and using numerical modelling.

  1. Improved modified pressure imaging and software for egg micro-crack detection and egg quality grading

    USDA-ARS?s Scientific Manuscript database

    Cracks in the egg shell increase a food safety risk. Especially, eggs with very fine, hairline cracks (micro-cracks) are often undetected during the grading process because they are almost impossible to detect visually. A modified pressure imaging system was developed to detect eggs with micro-crack...

  2. UWB micro-doppler radar for human gait analysis using joint range-time-frequency representation

    NASA Astrophysics Data System (ADS)

    Wang, Yazhou; Fathy, Aly E.

    2013-05-01

    In this paper, we present a novel, standalone ultra wideband (UWB) micro-Doppler radar sensor that goes beyond simple range or micro-Doppler detection to combined range-time-Doppler frequency analysis. Moreover, it can monitor more than one human object in both line-of-sight (LOS) and through wall scenarios, thus have full human objects tracking capabilities. The unique radar design is based on narrow pulse transceiver, high speed data acquisition module, and wideband antenna array. For advanced radar post-data processing, joint range-time-frequency representation has been performed. Characteristics of human walking activity have been analyzed using the radar sensor by precisely tracking the radar object and acquiring range-time-Doppler information simultaneously. The UWB micro-Doppler radar prototype is capable of detecting Doppler frequency range from -180 Hz to +180 Hz, which allows a maximum target velocity of 9 m/s. The developed radar sensor can also be extended for many other applications, such as respiration and heartbeat detection of trapped survivors under building debris.

  3. Pneumatic Micro Dispenser Chip for Portable Micro Analysis Devices

    NASA Astrophysics Data System (ADS)

    Hasegawa, Tadahiro; Tsuji, Toshiyuki; Ikuta, Koji

    The prototype of the pneumatic micro dispenser chip for portable micro analysis devices was developed successfully. This micro dispenser succeeded to divide liquid into 1µL without any dead volume by decompressing and the compressing air in only one micro pump. The dispensing operation is achieved by the original micro liquid detecting method and four hat-shaped check valves. The detecting method utilized the refraction of the infrared rays LED. Not only passage of the fluid into the channel but also its existence can be detected as TTL level signal. The hat-shaped silicone rubber valve which functions itself as a unidirectional passive valve was proposed. The check valve with low opening pressure (3kPa) and high inverse pressure (over 300kPa) was developed successfully. This micro dispenser chip is useful for portable micro analysis devices.

  4. Quartz technology allows for wider downhole pressure testing range

    SciTech Connect

    Dennis, J.R. ); Zeller, V.P. )

    1991-03-01

    This paper presents a quartz-thickness shear-mode transducer for use in a borehole environment. The pressure sensor is a direct-conversion device that uses a noncylindrical shell to convert and to transmit forces to the quartz-crystal resonator. A brief conceptual description of the transducer is given. Laboratory and field examples illustrate the exceptional performance of the quartz-thickness shear-mode transducer.

  5. OH radical production in an atmospheric pressure surface micro-discharge array

    NASA Astrophysics Data System (ADS)

    Li, D.; Nikiforov, A.; Britun, N.; Snyders, R.; Kong, M. G.; Leys, C.

    2016-11-01

    The generation of OH radicals from an array of surface micro-discharges working in atmospheric pressure He/Ar/H2O mixtures is investigated. The absolute OH density and its temporal-and-spatial dynamics are detected by UV broadband absorption spectroscopy (UV-BAS) and laser-induced fluorescence (LIF) spectroscopy. The measured absolute density of OH(X) state is about 1021 m-3 in Ar/H2O mixture reaching a peak at 0.05% of H2O. In the case of He/H2O mixtures however, the peaking at ~1019 m-3 is approximately two orders of magnitude lower and decreases monotonously with increasing H2O content. From a control standpoint, the ratio of the Ar/He mixture may be adjusted to tune the OH density over two orders of magnitude and to modulate the H2O content dependence of the OH density. The capability of modulating the OH radical production over a large density range is of practical interest for many applications such as atmospheric chemistry and biochemistry. With the array of atmospheric micro-discharges sustained over a large electrode area, a uniform distribution of its OH density can be achieved in a plane parallel to the electrodes thus enabling spatially controlled surface treatment of large samples.

  6. Pressure Generation from Micro-Bubble Collapse at Shock Wave Loading

    NASA Astrophysics Data System (ADS)

    Abe, Akihisa; Ohtani, Kiyonobu; Takayama, Kazuyoshi; Nishio, Shigeru; Mimura, Haruo; Takeda, Minoru

    This paper reports the result of a primary experimental and analytical study used to explore a reliable technology that is potentially applicable to the inactivation of micro-creatures contained in ship ballast water. A shock wave generated by the micro-explosion of a 10mg silver azide pellet in a 10mm wide parallel test section was used to interact with a bubble cloud consisting of bubbles with average diameter 10µm produced by a swirling flow type micro-bubble generator. Observations were carried out with a high-speed camera, IMACON200, and the corresponding rebound pressures of the collapsing bubbles were measured with a fiber optic probe pressure transducer that provides high spatial and temporal resolutions. We found that micro-bubbles collapse in several hundred nanoseconds after the shock exposure and the resulting peak pressure pulses that repeatedly occurred exceeded well over 200MPa measured at the 20mm distance from the explosion center. These continued for well over 20µs. The experimental pressure responses were explained by solving the one-dimensional bubble Rayleigh-Plesset equation. Such high peak pressures could be used effectively for the inactivation of micro-creatures contained in ship ballast water.

  7. Using a laser range finder mounted on a MicroVision robot to estimate environmental parameters

    NASA Astrophysics Data System (ADS)

    Fehr, Duc; Papanikolopoulos, Nikos

    2009-05-01

    In this article we will present a new robot (MicroVision) that has been designed at the University of Minnesota (UMN), Center for Distributed Robotics. Its design reminds of the designs of previous robots built at the UMN such as the COTS Scouts or the eROSIs. It is composed of a body with two wheels and a tail just like the two aforementioned robots. However, the MicroVision has more powerful processing and sensing capabilities and we utilized these to compute areas in the surrounding environment by using a convex hull approach. We are trying to estimate the projected area of an object onto the ground. This is done by the computation of convex hulls that are based on the data received from the MicroVision's laser range finder. Although localization of the robot is an important feature in being able to compute these convex hulls, localization and mapping techniques are only used as a tool and are not an end in this work. The main idea of this work is to demonstrate the ability of the laser carrying MicroVision robot to move around an object in order to get a scan from each side. From these scans, the convex hull of the shape is deduced and its projected area onto the ground is estimated.

  8. Review of the STM range of pressure distribution products.

    PubMed

    Moody, M

    STM Healthcare is a division of the Recticel Group which has been actively involved in the production and use of polyurethane foams for the past 40 years, and is now one of Europe's leading manufacturers of polyurethane foam for insulation, packaging, filtration, aerospace, the automotive and furniture industries, domestic and specialist bedding and seating products. STM Healthcare is able to draw upon the wealth of experience and expertise of the manufacturing facilities, enabling products to be developed using the latest environmentally friendly specification foams best suited to the requirements of pressure-reduction technology. All STM Healthcare mattresses, cushions and Linknurse mattresses are manufactured with Safeguard combustion modified high resilience foams. (Linknurse is a licensed product name; products are manufactured by Recticel and distributed by STM).

  9. Validation of a new micro-manometer pressure sensor for cardiovascular measurements in mice.

    PubMed

    Trevino, Rodolfo J; Jones, Douglas L; Escobedo, Daniel; Porterfield, John; Larson, Erik; Chisholm, Gary B; Barton, Amanda; Feldman, Marc D

    2010-01-01

    Abstract The Scisense (London, ON, Canada) micro-manometer pressure sensor is currently being used by investigators to evaluate cardiovascular physiology in mice, but has not been validated to date. The purpose of the current study is to compare the 1.2 F Scisense pressure sensor to the current gold standard produced by Millar Instruments (Houston, TX) (1.4 F). In vitro comparisons were preformed including temperature drift, frequency response analysis up to 250 Hz, and damping coefficient and natural frequency determined via a pop test. The authors also performed in vivo comparisons including pressure drift, dose-response studies to IV isoproterenol, maximum adrenergic stimulation with IV dobutamine, and simultaneous placement of both micro-manometer pressure sensors in the same intact murine hearts. The authors conclude that both sensors are equivalent, and that the Scisense pressure sensor represents an alternative to the current gold standard, the Millar micro-manometer pressure sensor for in vivo pressure measurements in the mouse.

  10. Phenomenological modeling of long range noncontact friction in micro- and nanoresonators

    SciTech Connect

    Gusso, Andre

    2011-09-15

    Motivated by the results of an experiment using atomic force microscopy performed by Gotsmann and Fuchs [Phys. Rev. Lett. 86, 2597 (2001)], where a strong energy loss due to the tip-sample interaction was measured, we investigate the potential implications of this energy loss channel to the quality factor of suspended micro- and nanoresonators. Because the observed tip-sample dissipation remains without a satisfactory theoretical explanation, two phenomenological models are proposed to generalize the experimental observations. In the minimal phenomenological model the range of validity of the power law found experimentally for the damping coefficient is assumed to be valid for larger separations. A more elaborate phenomenological model assumes that the noncontact friction is a consequence of the Casimir force acting between the closely spaced surfaces. Both models provide quantitative results for the noncontact friction between any two objects which are then used to estimate the energy loss for suspended bar micro- and nanoresonators. It is concluded that the energy loss due to the unknown mechanism has the potential to seriously restrict the quality factor of both micro- and nanoresonators.

  11. High Resolution and Large Dynamic Range Resonant Pressure Sensor Based on Q-Factor Measurement

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C. (Inventor); Stell, Christopher B. (Inventor); Tang, Tony K. (Inventor); Vorperian, Vatche (Inventor); Wilcox, Jaroslava (Inventor); Shcheglov, Kirill (Inventor); Kaiser, William J. (Inventor)

    2000-01-01

    A pressure sensor has a high degree of accuracy over a wide range of pressures. Using a pressure sensor relying upon resonant oscillations to determine pressure, a driving circuit drives such a pressure sensor at resonance and tracks resonant frequency and amplitude shifts with changes in pressure. Pressure changes affect the Q-factor of the resonating portion of the pressure sensor. Such Q-factor changes are detected by the driving/sensing circuit which in turn tracks the changes in resonant frequency to maintain the pressure sensor at resonance. Changes in the Q-factor are reflected in changes of amplitude of the resonating pressure sensor. In response, upon sensing the changes in the amplitude, the driving circuit changes the force or strength of the electrostatic driving signal to maintain the resonator at constant amplitude. The amplitude of the driving signals become a direct measure of the changes in pressure as the operating characteristics of the resonator give rise to a linear response curve for the amplitude of the driving signal. Pressure change resolution is on the order of 10(exp -6) torr over a range spanning from 7,600 torr to 10(exp -6) torr. No temperature compensation for the pressure sensor of the present invention is foreseen. Power requirements for the pressure sensor are generally minimal due to the low-loss mechanical design of the resonating pressure sensor and the simple control electronics.

  12. Laboratory investigation of high pressure survival in Shewanella oneidensis MR-1 into the gigapascal pressure range

    PubMed Central

    Hazael, Rachael; Foglia, Fabrizia; Kardzhaliyska, Liya; Daniel, Isabelle; Meersman, Filip; McMillan, Paul

    2014-01-01

    The survival of Shewanella oneidensis MR-1 at up to 1500 MPa was investigated by laboratory studies involving exposure to high pressure followed by evaluation of survivors as the number (N) of colony forming units (CFU) that could be cultured following recovery to ambient conditions. Exposing the wild type (WT) bacteria to 250 MPa resulted in only a minor (0.7 log N units) drop in survival compared with the initial concentration of 108 cells/ml. Raising the pressure to above 500 MPa caused a large reduction in the number of viable cells observed following recovery to ambient pressure. Additional pressure increase caused a further decrease in survivability, with approximately 102 CFU/ml recorded following exposure to 1000 MPa (1 GPa) and 1.5 GPa. Pressurizing samples from colonies resuscitated from survivors that had been previously exposed to high pressure resulted in substantially greater survivor counts. Experiments were carried out to examine potential interactions between pressure and temperature variables in determining bacterial survival. One generation of survivors previously exposed to 1 GPa was compared with WT samples to investigate survival between 37 and 8°C. The results did not reveal any coupling between acquired high pressure resistance and temperature effects on growth. PMID:25452750

  13. Effects of air-sea interaction on extended-range prediction of geopotential height at 500 hPa over the northern extratropical region

    NASA Astrophysics Data System (ADS)

    Wang, Xujia; Zheng, Zhihai; Feng, Guolin

    2017-02-01

    The contribution of air-sea interaction on the extended-range prediction of geopotential height at 500 hPa in the northern extratropical region has been analyzed with a coupled model form Beijing Climate Center and its atmospheric components. Under the assumption of the perfect model, the extended-range prediction skill was evaluated by anomaly correlation coefficient (ACC), root mean square error (RMSE), and signal-to-noise ratio (SNR). The coupled model has a better prediction skill than its atmospheric model, especially, the air-sea interaction in July made a greater contribution for the improvement of prediction skill than other months. The prediction skill of the extratropical region in the coupled model reaches 16-18 days in all months, while the atmospheric model reaches 10-11 days in January, April, and July and only 7-8 days in October, indicating that the air-sea interaction can extend the prediction skill of the atmospheric model by about 1 week. The errors of both the coupled model and the atmospheric model reach saturation in about 20 days, suggesting that the predictable range is less than 3 weeks.

  14. Analysis of Mach-Zehnder interferometric micro-opto-electro-mechanical (MOEM) pressure sensor

    NASA Astrophysics Data System (ADS)

    Srinivas, Talabuttala; Pattnaik, Prasant K.; Narayana, T. Badri; Selvarajan, Ananth

    1999-11-01

    Combination of Integrated Optics and micro-machining technologies offer immense potential for sensor applications. Small mechanical deformations can often produce considerable changes in optical properties of devices resulting in drastically improved sensitivities. Here we prose and analyze a novel pressure sensor consisting of integrated optic Mach-Zehnder interferometer whose sensing arm is fabricated on a silicon micro-machined diaphragm. The analysis consists of determining the changes in optical output corresponding to the diaphragm deflections due to impressed pressure. Dynamical equations of motion are solved and resulting displacement fields are related to refractive index and optical path length changes of the Mach-Zehnder interferometer. Results can be used to obtain the change in sensitivity due to change sin path length and refractive index variations. The analysis can easily be applied to other MOEM sensor devices like those consisting of micro-machined vibrating cantilevers and bridges controlling optical waveguides, directional couplers or multi-mode-multi-waveguide structures.

  15. A normally-closed piezoelectric micro-valve with flexible stopper

    NASA Astrophysics Data System (ADS)

    Chen, Song; Lu, Song; Liu, Yong; Wang, Jiantao; Tian, Xiaochao; Liu, Guojun; Yang, Zhigang

    2016-04-01

    In the field of controlled drug delivery system, there are still many problems on those reported micro-valves, such as the small opening height, unsatisfactory particle tolerance and high cost. To solve the above problems, a novel normally-closed piezoelectric micro-valve is presented in this paper. The micro-valve was driven by circular unimorph piezoelectric vibrator and natural rubber membrane with high elasticity was used as the valve stopper. The small axial displacement of piezoelectric vibrator can be converted into a large stroke of valve stopper based on hydraulic amplification mechanism. The experiment indicates that maximum hydraulic amplification ratio is up to 14, and the cut-off pressure of the micro-valve is 39kPa in the case of no working voltage. The presented micro valve has a large flow control range (ranging from 0 to 8.75mL/min).

  16. Low pressure micro-Joule picosecond laser-induced breakdown spectroscopy and its prospective applications to minimally destructive and high resolution analysis

    NASA Astrophysics Data System (ADS)

    Nur Abdulmadjid, Syahrun; Jobiliong, Eric; Margaretha Suliyanti, Maria; Pardede, Marincan; Suyanto, Hery; Hendrik Kurniawan, Koo; Jie Lie, Tjung; Hedwig, Rinda; Sukra Lie, Zener; Karnadi, Indra; Wihardjo, Erning; Tjia, May On; Kagawa, Kiichiro

    2017-09-01

    A time-resolved spectroscopic study is performed by using 125-500 micro-Joule (µJ) ps laser focused directly without the aid of microscope on a Cu plate sample in a variety of low-pressure ambient gases including air, helium and argon. It is shown that the ultrashort µJ laser-induced low-pressure plasma in Ar ambient gas exhibits the typical characteristics of shock wave plasma responsible for the thermal excitation and sharp emission of the analyte atoms. It is found that the highest signal to background (S/B) ratio of about 100 is achieved in 1.3 kPa argon ambient gas and detected with optical multichannel analyzer (OMA) gate delay of 1 ns and gate width of 50 µs. The emission spectra obtained from pure Zn sample show the effective suppression of the ionic emission with ablation energy around and below 500 µJ. The experimental setup is successfully applied to Cr analysis with low detection limit in steel. In particular, its application to C analysis in steel is demonstrated to resolve the long standing problem of overlapping contributions from the neutral and ionic Fe emission. It is further found that an element of high excitation energy such as fluorine (F) can be clearly detected from a non metal teflon sample. Further, its application to alluminum sample containing various concentrations of Mg, Ca, Fe, and Si impurity elements clearly displays the existence of linear calibration lines promising for quantitative analyses in certain dynamical ranges. Finally, in view of the tiny crater sizes of less than 10 µm diameter created by the very low ps laser energy, this technique is promising for micrometer resolution mapping of elemental distribution on the sample surface and its depth profiling.

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

    SciTech Connect

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

    2015-06-10

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

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

    DOE PAGES

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

    2015-06-10

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

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

    PubMed Central

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

    2012-01-01

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

  20. Full Dynamic-Range Pressure Sensor Matrix Based on Optical and Electrical Dual-Mode Sensing.

    PubMed

    Wang, Xiandi; Que, Miaoling; Chen, Mengxiao; Han, Xun; Li, Xiaoyi; Pan, Caofeng; Wang, Zhong Lin

    2017-04-01

    A pressure-sensor matrix (PSM) with full dynamic range can accurately detect and spatially map pressure profiles. A 100 × 100 large-scale PSM gives both electrical and optical signals by itself without applying an external power source. The device represents a major step toward digital imaging, and the visible display of the pressure distribution covers a large dynamic range. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. KEY COMPARISON: Final report of APMP pressure key comparison (APMP.M.P-K6) in gas media and gauge mode from 20 kPa to 105 kPa

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, A. K.; Woo, Sam Yong; Fitzgerald, Mark; Man, John; Ooiwa, Akira; Jescheck, M.; Jian, Wu; Fatt, Chen Soo; Chan, T. K.; Moore, Ken

    2008-01-01

    This report summarizes the results of a regional key comparison (APMP-IC-2-97) under the aegis of Asia Pacific Metrology Program (APMP) for pressure measurements in gas media and in gauge mode from 20 kPa to 105 kPa. The transfer standard was a pressure-balance with a piston-cylinder assembly with nominal effective area 335.7 mm2 (TL-391) and was supplied by the National Metrology Institute of Japan [NMIJ]. Nine standards laboratories from the APMP region with one specially invited laboratory from the EUROMET region, namely Physikalisch-Technische Bundesanstalt (PTB), Germany, participated in this comparison. The comparison started in October 1998 and was completed in May 2001. The pilot laboratory prepared the calibration procedure as per the guidelines of APMP and International Bureau of Weights and Measures (BIPM) [1-4]. Detailed instructions for performing this key comparison were provided in the calibration protocol and the required data were described in: (1) Annex 3 - characteristics of the laboratory standards, (2) Annex 4 - the effective area (A'p'/mm2) (where the prime indicates values based on measured quantities) at 23 °C of the travelling standard as a function of nominal pressure (p'/kPa) (five cycles both increasing and decreasing pressures at five predetermined pressure points) and (3) Annex 5 - the average effective area at 23 °C (A'p'/mm2) obtained for each pressure p'/kPa with all uncertainty statements. The pilot laboratory processed the information and the data provided by the participants for these three annexes, starting with the information about the standards as provided in Annex 3. Based on this information, the participating laboratories are classified into two categories: (I) laboratories that are maintaining primary standards, and (II) laboratories that are maintaining standards loosely classified as secondary standards with a clear traceability from other established national metrology institutes (NMI) as per norm of the BIPM. It is

  2. Micro X-ray CT Imaging of Sediments under Confining Pressure

    NASA Astrophysics Data System (ADS)

    Schindler, M.; Prasad, M.

    2016-12-01

    We developed a pressure and temperature control system for use inside the micro X-ray CT scanner Xradia 400. We succeeded in building a pressure vessel that can be pressurized to 34.5 MPa (5000 psi) while being transparent to X-rays. The setup can currently be cooled to -5 C and heated to 40 C. We were able to observe grain damage and porosity reduction due to applied confining pressure in clean quartz sand samples and quartz sand and bentonite samples. By comparing micro CT images at atmospheric pressure and 13.8 MPa (2000 psi) confining pressure, we observed compaction of the samples resulting in grain damage and fracturing of sediment grains (Figure 1). When the confining pressure was decreased some grains experienced further fracturing. The grain damage appears irreversible. Further fracturing of grains in pre-compacted sediment was observed upon repeated confining pressure cycling. We are currently working on feed-throughs for fluid lines and electric wiring to use ultrasonic transducers and pressure control in combination. Further we plan to include pore pressure in addition to confining pressure into the system. The pressure control system in combination with ultrasonic transducers will allow us to visually observe pore scale changes in rock samples while simultaneously identifying their influence on ultrasonic velocities. Such pore-scale changes are usually not taken into account by rock physics models and could help to identify why laboratory data diverges from theoretical models. Further, it is possible to compute compressibility from mCT images at different stress states by image correlation

  3. Mass flow rate and pressure distribution of gas through three-dimensional micro-channels

    SciTech Connect

    Jiang, Jianzheng; Fan, Jing

    2014-12-09

    An effective method to predict the mass flow rate and pressure distribution of gas through three dimensional micro-channels with different cross-section shapes has been proposed. For rectangular cross sections often employed in experiment, the present solutions versus measured data of Zohar et al. (2002) show that the side walls significantly affect the mass flow rates as the aspect ratio is smaller than 10, whereas the non-dimensional pressure distributions, mainly determined by the inlet-to-outlet pressure ratio, are insensitive to the aspect ratio.

  4. [An implantable micro-device using wireless power transmission for measuring aortic aneurysm sac pressure].

    PubMed

    Guo, Xudong; Ge, Bin; Wang, Wenxing

    2013-08-01

    In order to detect endoleaks after endovascular aneurysm repair (EVAR), we developed an implantable micro-device based on wireless power transmission to measure aortic aneurysm sac pressure. The implantable micro-device is composed of a miniature wireless pressure sensor, an energy transmitting coil, a data recorder and a data processing platform. Power transmission without interconnecting wires is performed by a transmitting coil and a receiving coil. The coupling efficiency of wireless power transmission depends on the coupling coefficient between the transmitting coil and the receiving coil. With theoretical analysis and experimental study, we optimized the geometry of the receiving coil to increase the coupling coefficient. In order to keep efficiency balance and satisfy the maximizing conditions, we designed a closed loop power transmission circuit, including a receiving voltage feedback module based on wireless communication. The closed loop improved the stability and reliability of transmission energy. The prototype of the micro-device has been developed and the experiment has been performed. The experiments showed that the micro-device was feasible and valid. For normal operation, the distance between the transmitting coil and the receiving coil is smaller than 8cm. Besides, the distance between the micro-device and the data recorder is within 50cm.

  5. Carbon nanotubes on polymer-based pressure micro-sensor for manometric catheters

    NASA Astrophysics Data System (ADS)

    Teng, M. F.; Hariz, A.; Hsu, H. Y.; Omari, T.

    2008-12-01

    In this paper we investigate the fabrication process of a novel polymer based pressure micro-sensor for use in manometric measurements in medical diagnostics. Review and analysis of polymer materials properties and polymer based sensors has been carried out and has been reported by us elsewhere [1]. The interest in developing a novel polymer based flexible pressure micro-sensor was motivated by the numerous problems inherent in the currently available manometric catheters used in the hospitals. The most critical issue regarding existing catheters was the running and maintenance costs [2]. Thus expensive operation costs lead to reuse of the catheters, which increase the risk for disease transmission. The novel flexible polymer based pressure micro-sensor was build using SU-8, which is a special kind of negative photoresist. Single-walled carbon nanotubes (SWCNTs) and aluminum are used as the sensing material and contacting electrodes respectively. The pressure sensor diaphragm was first patterned on top of an oxidized silicon wafer using SU-8, followed by aluminum deposition to define the electrodes. The carbon nanotube is then deposited using dielectrophoresis (DEP) process. Once the carbon nanotubes are aligned in between these electrodes, the remaining of the sensor structure is formed using SU-8. Patterning of SU-8 and release from the substrate make the device ready for further testing of sensing ability. This research not only investigates the use of polymeric materials to build pressure sensors, but also explores the feasibility of full utilization of polymeric materials to replace conventional silicon materials in micro-sensors fabrication for use in medical environments. The completed sensor is expected to form an integral part of a large versatile sensing system. For example, the biocompatible artificial skin, is predicted to be capable of sensing force, pressure, temperature, and humidity, and may be used in such applications as medical and robotic system.

  6. Micro-controller based air pressure monitoring instrumentation system using optical fibers as sensor

    NASA Astrophysics Data System (ADS)

    Hazarika, D.; Pegu, D. S.

    2013-03-01

    This paper describes a micro-controller based instrumentation system to monitor air pressure using optical fiber sensors. The principle of macrobending is used to develop the sensor system. The instrumentation system consists of a laser source, a beam splitter, two multi mode optical fibers, two Light Dependent Resistance (LDR) based timer circuits and a AT89S8252 micro-controller. The beam splitter is used to divide the laser beam into two parts and then these two beams are launched into two multi mode fibers. One of the multi mode fibers is used as the sensor fiber and the other one is used as the reference fiber. The use of the reference fiber is to eliminate the environmental effects while measuring the air pressure magnitude. The laser beams from the sensor and reference fibers are applied to two identical LDR based timer circuits. The LDR based timer circuits are interfaced to a micro-controller through its counter pins. The micro-controller samples the frequencies of the timer circuits using its counter-0 and counter-1 and the counter values are then processed to provide the measure of air pressure magnitude.

  7. Large Area One-Step Facile Processing of Microstructured Elastomeric Dielectric Film for High Sensitivity and Durable Sensing over Wide Pressure Range.

    PubMed

    Chen, Sujie; Zhuo, Bengang; Guo, Xiaojun

    2016-08-10

    Once the requirement of sensitivity has been met, to enable a flexible pressure sensor technology to be widely adopted as an economic and convenient way for sensing diverse human body motions, critical factors need to be considered including low manufacturing cost, a large pressure detection range, and low power consumption. In this work, a facile approach is developed for one-step processing of a large area microstructured elastomer film with high density microfeatures of air voids, which can be seamlessly integrated into the process flow for fabricating flexible capacitive sensors. The fabricated sensors exhibit fast response and high sensitivity in the low pressure range to be able to detect very weak pressure down to 1 Pa and perform reliable wrist pulse monitoring. Compared to previous work, more advantageous features of this sensor are relatively high sensitivity being maintained in a wide pressure range up to 250 kPa and excellent durability under heavy load larger than 1 MPa, attributed to the formed dense air voids inside the film. A smart insole made with the sensor can accurately monitor the real-time walking or running behaviors and even a small weight change less than 1 kg under a heavy load of a 70 kg adult. For both application examples of wrist pulse monitoring and smart insole, the sensors are operated in a 3.3 V electronic system powered by a Li-ion battery, showing the potential for power-constrained wearable applications.

  8. Airway pressure release ventilation reduces conducting airway micro-strain in lung injury.

    PubMed

    Kollisch-Singule, Michaela; Emr, Bryanna; Smith, Bradford; Ruiz, Cynthia; Roy, Shreyas; Meng, Qinghe; Jain, Sumeet; Satalin, Joshua; Snyder, Kathy; Ghosh, Auyon; Marx, William H; Andrews, Penny; Habashi, Nader; Nieman, Gary F; Gatto, Louis A

    2014-11-01

    Improper mechanical ventilation can exacerbate acute lung damage, causing a secondary ventilator-induced lung injury (VILI). We hypothesized that VILI can be reduced by modifying specific components of the ventilation waveform (mechanical breath), and we studied the impact of airway pressure release ventilation (APRV) and controlled mandatory ventilation (CMV) on the lung micro-anatomy (alveoli and conducting airways). The distribution of gas during inspiration and expiration and the strain generated during mechanical ventilation in the micro-anatomy (micro-strain) were calculated. Rats were anesthetized, surgically prepared, and randomized into 1 uninjured control group (n = 2) and 4 groups with lung injury: APRV 75% (n = 2), time at expiration (TLow) set to terminate appropriately at 75% of peak expiratory flow rate (PEFR); APRV 10% (n = 2), TLow set to terminate inappropriately at 10% of PEFR; CMV with PEEP 5 cm H2O (PEEP 5; n = 2); or PEEP 16 cm H2O (PEEP 16; n = 2). Lung injury was induced in the experimental groups by Tween lavage and ventilated with their respective settings. Lungs were fixed at peak inspiration and end expiration for standard histology. Conducting airway and alveolar air space areas were quantified and conducting airway micro-strain was calculated. All lung injury groups redistributed inspired gas away from alveoli into the conducting airways. The APRV 75% minimized gas redistribution and micro-strain in the conducting airways and provided the alveolar air space occupancy most similar to control at both inspiration and expiration. In an injured lung, APRV 75% maintained micro-anatomic gas distribution similar to that of the normal lung. The lung protection demonstrated in previous studies using APRV 75% may be due to a more homogeneous distribution of gas at the micro-anatomic level as well as a reduction in conducting airway micro-strain. Copyright © 2014 American College of Surgeons. All rights reserved.

  9. Feature extraction of micro-motion frequency and the maximum wobble angle in a small range of missile warhead based on micro-Doppler effect

    NASA Astrophysics Data System (ADS)

    Li, M.; Jiang, Y. S.

    2014-11-01

    Micro-Doppler effect is induced by the micro-motion dynamics of the radar target itself or any structure on the target. In this paper, a simplified cone-shaped model for ballistic missile warhead with micro-nutation is established, followed by the theoretical formula of micro-nutation is derived. It is confirmed that the theoretical results are identical to simulation results by using short-time Fourier transform. Then we propose a new method for nutation period extraction via signature maximum energy fitting based on empirical mode decomposition and short-time Fourier transform. The maximum wobble angle is also extracted by distance approximate approach in a small range of wobble angle, which is combined with the maximum likelihood estimation. By the simulation studies, it is shown that these two feature extraction methods are both valid even with low signal-to-noise ratio.

  10. Quantitative analysis of terahertz spectra for illicit drugs using adaptive-range micro-genetic algorithm

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Ma, Yong; Lu, Zheng; Peng, Bei; Chen, Qin

    2011-08-01

    In the field of anti-illicit drug applications, many suspicious mixture samples might consist of various drug components—for example, a mixture of methamphetamine, heroin, and amoxicillin—which makes spectral identification very difficult. A terahertz spectroscopic quantitative analysis method using an adaptive range micro-genetic algorithm with a variable internal population (ARVIPɛμGA) has been proposed. Five mixture cases are discussed using ARVIPɛμGA driven quantitative terahertz spectroscopic analysis in this paper. The devised simulation results show agreement with the previous experimental results, which suggested that the proposed technique has potential applications for terahertz spectral identifications of drug mixture components. The results show agreement with the results obtained using other experimental and numerical techniques.

  11. PA171 Containers on a Wood Pallet with Metal Top Adapter, Air Pressure Tests During MIL-STD-1660 Tests

    DTIC Science & Technology

    2004-12-01

    DECK BOARDS WIS-6d NAILS AND CLINCH4. SPECIAL 40"r X 44r PALLET . PALLET TO PROVIDE ADDITIONAL SUPPORT FOR STEEL NEED NOT HAVE CHAMFERS OR STRAPPING, THE...1" XS" STRINGER PALLET DUNNAGE LOCATION BOARDS MAYBE POSITIONEDAS SHOWN. BUFFER PIECE, OAK, 1-Xe- X 44". 8-115" BIDE BUFFER 2 REQD. DUNNAGE DETAILS PAGE 3 ...FINAL REPORT December 2004 REPORT NO. 04-22 PAI71 CONTAINERS ON A WOOD PALLET WITH METAL TOP ADAPTER, AIR PRESSURE TESTS DURING MIL-STD-1660 TESTS

  12. Plasma-polymerized methyl methacrylate via intense and highly energetic atmospheric pressure micro-plasma for bio-medical applications

    NASA Astrophysics Data System (ADS)

    Park, Choon-Sang; Ballato, John; Kim, Sung-O.; Clemson University Team

    2013-09-01

    Poly (methyl methacrylate), PMMA, has been widely used as a biocompatible material in bone cement, dental fillings, and many other bio-related applications. Vacuum plasmas and radio frequency (RF) atmospheric plasmas are the most common methods for depositing plasma-derived thin films and nanoparticles. However, the necessary equipment is difficult to operate and maintain as well as being large and expensive. Here, we report the use of a novel intense and highly energetic atmospheric pressure plasma jet array using direct plasma jet-to-jet coupling effects to deposit high quality plasma-polymerized MMA (PPMMA) for bio-medical applications. The newly proposed atmospheric pressure micro-plasma jet array device can generate the intense plasma mode with a strong plasma emission and high plasma particle energy. PPMMA was successfully deposited on a variety of substrates and characterized by SEM, AFM, and FT-IR. The micro-plasma jet is obtained at a sinusoidal voltage with a peak value of 30 kV and frequency of 35 kHz. Argon gas was employed as the discharge gas for plasma generation and its flow rate was in the range of 2230 sccm, Methyl methacrylate (MMA) monomer was vaporized by means of a glass bubbler which was supplied by argon gas with flow rates in the range of 268 sccm from room temperature to 400°C. The deposited PPMMA thin films were flexible, transparent, thin, and strong on metal substrates.

  13. Highly Sensitive, Flexible MEMS Based Pressure Sensor with Photoresist Insulation Layer.

    PubMed

    Liang, Binghao; Chen, Wenjun; He, Zhongfu; Yang, Rongliang; Lin, Zhiqiang; Du, Huiwei; Shang, Yuanyuan; Cao, Anyuan; Tang, Zikang; Gui, Xuchun

    2017-09-29

    Pressure sensing is a crucial function for flexible and wearable electronics, such as artificial skin and health monitoring. Recent progress in material and device structure of pressure sensors has brought breakthroughs in flexibility, self-healing, and sensitivity. However, the fabrication process of many pressure sensors is too complicated and difficult to integrate with traditional silicon-based Micro-Electro-Mechanical System(MEMS). Here, this study demonstrates a scalable and integratable contact resistance-based pressure sensor based on a carbon nanotube conductive network and a photoresist insulation layer. The pressure sensors have high sensitivity (95.5 kPa(-1) ), low sensing threshold (16 Pa), fast response speed (<16 ms), and zero power consumption when without loading pressure. The sensitivity, sensing threshold, and dynamic range are all tunable by conveniently modifying the hole diameter and thickness of insulation layer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Piezoresistive pressure sensor with high sensitivity for medical application using peninsula-island structure

    NASA Astrophysics Data System (ADS)

    Xu, Tingzhong; Wang, Hongyan; Xia, Yong; Zhao, Zhiming; Huang, Mimi; Wang, Jiuhong; Zhao, Libo; Zhao, Yulong; Jiang, Zhuangde

    2017-07-01

    A novel micro-electromechanical systems piezoresistive pressure sensor with a diagonally positioned peninsula-island structure has high sensitivity for ultralow- pressure measurement. The pressure sensor was designed with a working range of 0-500 Pa and had a high sensitivity of 0.06 mV·V-1·Pa-1. The trade-off between high sensitivity and linearity was alleviated. Moreover, the influence of the installation angle on the sensing chip output was analyzed, and an application experiment of the sensor was conducted using the built pipettor test platform. Findings indicated that the proposed pressure sensor had sufficient resolution ability and accuracy to detect the pressure variation in the pipettor chamber. Therefore, the proposed pressure sensor has strong potential for medical equipment application.

  15. [Investigation on the electron density of a micro-plasma jet operated at atmospheric pressure].

    PubMed

    Li, Xue-chen; Zhao, Na; Liu, Wei-yuan; Liu, Zhi-qiang

    2010-07-01

    In the present paper, a micro-hollow cathode discharge setup was used to generate micro-plasma jet in flowing mixture of Ar and N2 at atmospheric pressure. The characteristics of the micro-plasma jet were investigated by means of optical method and electrical one. It has been found that breakdown occurs in the gas between the two electrodes when the input power of electric source is increased to a certain value. Plasma appears along the gas flow direction when the mixed gas flows from the aperture of the micro-hollow cathode, and the length of plasma reaches 4 mm. The discharge current is quasi-continuous, and the duration of discharge pulse is about 0.1 micros. Electron density was studied by using Einstein equation and Stark broadening of spectral lines from the emission spectrum respectively. It was found that the results of electron density calculated by the two methods are consistent with the order of 10(15) x cm(-3). It was also found that the electron density is almost independent of power. A qualitative explanation to the phenomenon is given based on the gas discharge theory.

  16. Effects of granular soil micro-mechanics on the pressure-sinkage relationship

    NASA Astrophysics Data System (ADS)

    Cui, Liang; Avramidis, Savvas

    2013-06-01

    The pressure-sinkage relationship is a common and important issue in terrain mechanics to explore the soil-vehicle interaction for the off-road vehicles. There are a number of empirical pressure-sinkage relationships available, which were established by curve fitting to experimental data. However, not much research has been performed to establish the link between the micro-mechanics of soil and the pressure-sinkage relationship, e.g. the effect of soil density, inter-particle friction, particle rolling resistance, and different gravity. In this paper, the effects of micro-mechanical parameters of soil on the pressure-sinkage relationship were investigated using the Discrete Element Method (DEM). The pressure-sinkage relationship from the DEM simulations matched the result from the experimental tests on coarse sand. It has been found that the sinkage is quite sensitive to the inter-particle friction (particle surface roughness), but is not particularly sensitive to the soil-vehicle friction, which indicates that the sinkage of vehicle is mainly controlled by the soil strength. It is also found that the sinkage was influenced significantly by the particle rolling resistance, which is related to irregular particle geometry. Gravity also has a big effect on the sinkage, which means that the experiment test results obtained on the Earth should be scaled properly to be used in the design of martian rover or lunar rover.

  17. Evaluation of an Intervention to Maintain Endotracheal Tube Cuff Pressure Within Therapeutic Range

    PubMed Central

    Sole, Mary Lou; Su, Xiaogang; Talbert, Steve; Penoyer, Daleen Aragon; Kalita, Samar; Jimenez, Edgar; Ludy, Jeffery E.; Bennett, Melody

    2012-01-01

    Background Endotracheal tube cuff pressure must be kept within an optimal range that ensures ventilation and prevents aspiration while maintaining tracheal perfusion. Objectives To test the effect of an intervention (adding or removing air) on the proportion of time that cuff pressure was between 20 and 30 cm H2O and to evaluate changes in cuff pressure over time. Methods A repeated-measure crossover design was used to study 32 orally intubated patients receiving mechanical ventilation for two 12-hour shifts (randomized control and intervention conditions). Continuous cuff pressure monitoring was initiated, and the pressure was adjusted to a minimum of 22 cm H2O. Caregivers were blinded to cuff pressure data, and usual care was provided during the control condition. During the intervention condition, cuff pressure alarm or clinical triggers guided the intervention. Results Most patients were men (mean age, 61.6 years). During the control condition, 51.7% of cuff pressure values were out of range compared with 11.1% during the intervention condition (P < .001). During the intervention, a mean of 8 adjustments were required, mostly to add air to the endotracheal tube cuff (mean 0.28 [SD, 0.13] mL). During the control condition, cuff pressure decreased over time (P < .001). Conclusions The intervention was effective in maintaining cuff pressure within an optimal range, and cuff pressure decreased over time without intervention. The effect of the intervention on outcomes such as ventilator-associated pneumonia and tracheal damage requires further study. PMID:21362715

  18. Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

    PubMed Central

    Wang, Bing-Yu; Hsieh, Fan-Chun; Lin, Che-Yu; Chen, Shao-En; Chen, Fong-Zhi; Wu, Chia-Che

    2014-01-01

    In this study, we develop a clamped–clamped beam-type piezoelectric vacuum pressure sensing element. The clamped–clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10−6 to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage. PMID:25421736

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

    SciTech Connect

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

    2015-03-15

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

  20. Investigation of holder pressure and size effects in micro deep drawing of rectangular work pieces driven by piezoelectric actuator.

    PubMed

    Aminzahed, Iman; Mashhadi, Mahmoud Mosavi; Sereshk, Mohammad Reza Vaziri

    2017-02-01

    Micro forming is a manufacturing process to fabricate micro parts with high quality and a cost effective manner. Deep drawing could be a favorable method for production of complicated parts in macro and micro sizes. In this paper piezoelectric actuator is used as a novel approach in the field of micro manufacturing. Also, in current work, investigations are conducted with four rectangular punches and blanks with various thicknesses. Blank holder pressure effects on thickness distributions, punch force, and springback are studied. According to the results of this work, increasing of blank holder pressure in scaled deep drawing, in contrast to thickness of drawn part, leads to decrease in the punch forces and springback. Furthermore, it is shown that in micro deep drawing, the effects of holder pressure on mentioned parameters can be ignored.

  1. Age, PaO2/FIO2, and Plateau Pressure Score: A Proposal for a Simple Outcome Score in Patients With the Acute Respiratory Distress Syndrome.

    PubMed

    Villar, Jesús; Ambrós, Alfonso; Soler, Juan Alfonso; Martínez, Domingo; Ferrando, Carlos; Solano, Rosario; Mosteiro, Fernando; Blanco, Jesús; Martín-Rodríguez, Carmen; Fernández, María Del Mar; López, Julia; Díaz-Domínguez, Francisco J; Andaluz-Ojeda, David; Merayo, Eleuterio; Pérez-Méndez, Lina; Fernández, Rosa Lidia; Kacmarek, Robert M

    2016-07-01

    Although there is general agreement on the characteristic features of the acute respiratory distress syndrome, we lack a scoring system that predicts acute respiratory distress syndrome outcome with high probability. Our objective was to develop an outcome score that clinicians could easily calculate at the bedside to predict the risk of death of acute respiratory distress syndrome patients 24 hours after diagnosis. A prospective, multicenter, observational, descriptive, and validation study. A network of multidisciplinary ICUs. Six-hundred patients meeting Berlin criteria for moderate and severe acute respiratory distress syndrome enrolled in two independent cohorts treated with lung-protective ventilation. None. Using individual demographic, pulmonary, and systemic data at 24 hours after acute respiratory distress syndrome diagnosis, we derived our prediction score in 300 acute respiratory distress syndrome patients based on stratification of variable values into tertiles, and validated in an independent cohort of 300 acute respiratory distress syndrome patients. Primary outcome was in-hospital mortality. We found that a 9-point score based on patient's age, PaO2/FIO2 ratio, and plateau pressure at 24 hours after acute respiratory distress syndrome diagnosis was associated with death. Patients with a score greater than 7 had a mortality of 83.3% (relative risk, 5.7; 95% CI, 3.0-11.0), whereas patients with scores less than 5 had a mortality of 14.5% (p < 0.0000001). We confirmed the predictive validity of the score in a validation cohort. A simple 9-point score based on the values of age, PaO2/FIO2 ratio, and plateau pressure calculated at 24 hours on protective ventilation after acute respiratory distress syndrome diagnosis could be used in real time for rating prognosis of acute respiratory distress syndrome patients with high probability.

  2. Impact of early blood pressure variability on stroke outcomes after thrombolysis: the SAMURAI rt-PA Registry.

    PubMed

    Endo, Kaoru; Kario, Kazuomi; Koga, Masatoshi; Nakagawara, Jyoji; Shiokawa, Yoshiaki; Yamagami, Hiroshi; Furui, Eisuke; Kimura, Kazumi; Hasegawa, Yasuhiro; Okada, Yasushi; Okuda, Satoshi; Namekawa, Michito; Miyagi, Tetsuya; Osaki, Masato; Minematsu, Kazuo; Toyoda, Kazunori

    2013-03-01

    The present study determines associations between early blood pressure (BP) variability and stroke outcomes after intravenous thrombolysis. In 527 stroke patients receiving intravenous alteplase (0.6 mg/kg), BP was measured 8 times within the first 25 hours. BP variability was determined as ΔBP (maximum-minimum), standard deviation (SD), coefficient of variation, and successive variation. The systolic BP course was lower among patients with modified Rankin Scale (mRS) 0 to 1 than those without (P<0.001). Most of systolic BP variability profiles were significantly associated with outcomes. Adjusted odds ratios (95% confidence interval) per 10 mm Hg (or 10% for coefficient of variation) on symptomatic intracerebral hemorrhage were as follows: ΔBP, 1.33 (1.08-1.66); SD, 2.52 (1.26-5.12); coefficient of variation, 3.15 (1.12-8.84); and successive variation, 1.82 (1.04-3.10). The respective values were 0.88 (0.77-0.99), 0.73 (0.48-1.09), 0.77 (0.43-1.34), and 0.76 (0.56-1.03) for 3-month mRS 0 to 1; and 1.40 (1.14-1.75), 2.85 (1.47-5.65), 4.67 (1.78-12.6), and 1.99 (1.20-3.25) for death. Initial BP values before thrombolysis were not associated with any outcomes. Early systolic BP variability was positively associated with symptomatic intracerebral hemorrhage and death after intravenous thrombolysis.

  3. A peristaltic micro pump driven by a rotating motor with magnetically attracted steel balls.

    PubMed

    Du, Min; Ye, Xiongying; Wu, Kang; Zhou, Zhaoying

    2009-01-01

    In this paper, we present a membrane peristaltic micro pump driven by a rotating motor with magnetically attracted steel balls for lab-on-a-chip applications. The fabrication process is based on standard soft lithography technology and bonding of a PDMS layer with a PMMA substrate. A linear flow rate range ∼490 μL/min was obtained by simply varying the rotation speed of a DC motor, and a maximum back pressure of 592 Pa was achieved at a rotation speed of 43 rpm. The flow rate of the pump can also be adjusted by using steel balls with different diameters or changing the number of balls. Nevertheless, the micro pump can also work in high speed mode. A high back pressure up to 10 kPa was achieved at 500 rpm using a high speed DC motor, and an utmost flow rate up to 5 mL/min was reached.

  4. A Peristaltic Micro Pump Driven by a Rotating Motor with Magnetically Attracted Steel Balls

    PubMed Central

    Du, Min; Ye, Xiongying; Wu, Kang; Zhou, Zhaoying

    2009-01-01

    In this paper, we present a membrane peristaltic micro pump driven by a rotating motor with magnetically attracted steel balls for lab-on-a-chip applications. The fabrication process is based on standard soft lithography technology and bonding of a PDMS layer with a PMMA substrate. A linear flow rate range ∼490 μL/min was obtained by simply varying the rotation speed of a DC motor, and a maximum back pressure of 592 Pa was achieved at a rotation speed of 43 rpm. The flow rate of the pump can also be adjusted by using steel balls with different diameters or changing the number of balls. Nevertheless, the micro pump can also work in high speed mode. A high back pressure up to 10 kPa was achieved at 500 rpm using a high speed DC motor, and an utmost flow rate up to 5 mL/min was reached. PMID:22574035

  5. Measurement of capillary pressure in fuel cell diffusion media, micro-porous layers, catalyst layers, and interfaces

    NASA Astrophysics Data System (ADS)

    LaManna, Jacob M.; Bothe, James V.; Zhang, Feng Yuan; Mench, Matthew M.

    2014-12-01

    In this work, semi-empirical Leverett J-Function relationships relating capillary pressure and water saturation are experimentally derived for commercial and experimental polymer electrolyte fuel cell materials developed for automotive applications. Relationships were derived for Mitsubishi Rayon Corp. (MRC) U105 and General Motors (GM) experimental high tortuosity diffusion media (DM), the micro-porous layer (MPL), and the catalyst layer (CL). The standard Leverett J-Function under-predicted drainage curves for the DM at high saturation levels and significantly under-predicted the capillary pressure requirements for the MPL and CL across the entire saturation range. Composite structures were tested to understand interfacial effects for DM|MPL and MPL|CL. Each additional layer was found to superimpose its effects on capillary pressure onto the previous layers. The MPL formulation tested increased in porosity from a 136 nm peak average to a 153 nm peak average with increased surface porosity of the substrate. Additionally, small voids and pockets that accumulate liquid water were found to exist in the MPL|CL interface. The results of this work are useful for computational modelers seeking to enhance the resolution of their macroscopic multi-phase flow models which underestimate capillary pressure using the standard Leverett J-Function.

  6. Long-range nanopositioning and nanomeasuring machine for application to micro- and nanotechnology

    NASA Astrophysics Data System (ADS)

    Jäger, Gerd; Hausotte, Tino; Büchner, Hans-Joachim; Manske, Eberhard; Schmidt, Ingomar; Mastylo, Rostyslav

    2006-03-01

    The paper describes the operation of a high-precision long range three-dimensional nanopositioning and nanomeasuring machine (NPM-Machine). The NPM-Machine has been developed by the Institute of Process Measurement and Sensor Technology of the Technische Universität Ilmenau. The machine was successfully tested and continually improved in the last few years. The machines are operating successfully in several German and foreign research institutes including the Physikalisch-Technische Bundesanstalt (PTB). Three plane mirror miniature interferometers are installed into the NPM-machine having a resolution of less than 0,1 nm over the entire positioning and measuring range of 25 mm x 25 mm x 5 mm. An Abbe offset-free design of the three miniature plane mirror interferometers and applying a new concept for compensating systematic errors resulting from mechanical guide systems provide extraordinary accuracy with an expanded uncertainty of only 5 - 10 nm. The integration of several, optical and tactile probe systems and nanotools makes the NPM-Machine suitable for various tasks, such as large-area scanning probe microscopy, mask and wafer inspection, nanostructuring, biotechnology and genetic engineering as well as measuring mechanical precision workpieces, precision treatment and for engineering new material. Various developed probe systems have been integrated into the NPM-Machine. The measurement results of a focus sensor, metrological AFM, white light sensor, tactile stylus probe and of a 3D-micro-touch-probe are presented. Single beam-, double beam- and triple beam interferometers built in the NPM-Machine for six degrees of freedom measurements are described.

  7. Atmospheric pressure fluctuations in the far infrasound range and emergency transport events coded as circulatory system diseases

    NASA Astrophysics Data System (ADS)

    Didyk, L. A.; Gorgo, Yu. P.; Dirckx, J. J. J.; Bogdanov, V. B.; Buytaert, J. A. N.; Lysenko, V. A.; Didyk, N. P.; Vershygora, A. V.; Erygina, V. T.

    2008-09-01

    This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72 11.07 Pa, n = 87) compared to the low DHA (0.7 3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21 1.64, n = 229) compared to the high Rdn (1.65 7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.

  8. EUROMET Intercomparison in the Pressure Range 100 MPa to 700 (1000) MPa

    NASA Astrophysics Data System (ADS)

    Legras, J. C.; Jäger, J.; Molinar, G. F.; Palomino, S.; Quintas, J.; White, M. R.

    1994-01-01

    As part of the intercomparison decided upon by the CCM High Pressure Working Group in the pressure range 100 MPa to 700 MPa, an intercomparison has been carried out in the Western European countries. This paper gives the general results of the work. The standards intercompared were piston pressure balances of different types or pressure multipliers. The claimed relative uncertainties at the 1 standard deviation level were between 11 × 10-6 and 93 × 10-6 at 100 MPa, and between 27 × 10-6 and 216 × 10-6 at 700 MPa. Demonstrating a very good agreement, the observed relative differences of the measured pressures were inside +/- 50 × 10-6 at 100 MPa and +/- 170 × 10-6 at 700 MPa.

  9. High-pressure Fourier transform micro-Raman spectroscopic investigation of diiodine-heterocyclic thioamide adducts.

    PubMed

    dos Santos, João Henrique Z; Butler, Ian S; Daga, Vasiliki; Hadjikakou, Sotiris; Hadjiliadis, Nick

    2002-10-01

    The pressure dependences of the Fourier transform micro-Raman spectra of four heterocyclic thioamides [[(bztzdtH)I2] x I2] (1) (bztzdtH = benzothiazole-2-thione), [(bztzdtH)I2] (2), [[(tzdtH)2I+] x I3- x 2I2] (3) (tzdtH = thiazoline-2-thione), and [[(bzimtH)I2]2 x I2 x 2H2O] (4) (bzimtH = benzimidazole-2-thione) have been studied between ambient pressure and 50 kbar. For 1, generation of I3- ions through disproportionation reactions is evident as the pressure is increased. There are empirical linear correlations between the frequency and (I-I) bond length and the applied pressure. The iodine adduct of thioamide 2 is more sensitive to pressure when compared to the 1 or 4 iodine adducts. This difference in behavior may be attributed to differences in crystal structures or to a lower I-I bond order. Monitoring of other vibrational transitions of the thiomide structure reveals several less important pressure dependences.

  10. Human pressures predict species' geographic range size better than biological traits.

    PubMed

    Di Marco, Moreno; Santini, Luca

    2015-06-01

    Geographic range size is the manifestation of complex interactions between intrinsic species traits and extrinsic environmental conditions. It is also a fundamental ecological attribute of species and a key extinction risk correlate. Past research has primarily focused on the role of biological and environmental predictors of range size, but macroecological patterns can also be distorted by human activities. Here, we analyse the role of extrinsic (biogeography, habitat state, climate, human pressure) and intrinsic (biology) variables in predicting range size of the world's terrestrial mammals. In particular, our aim is to compare the predictive ability of human pressure vs. species biology. We evaluated the ability of 19 intrinsic and extrinsic variables in predicting range size for 4867 terrestrial mammals. We repeated the analyses after excluding restricted-range species and performed separate analyses for species in different biogeographic realms and taxonomic groups. Our model had high predictive ability and showed that climatic variables and human pressures are the most influential predictors of range size. Interestingly, human pressures predict current geographic range size better than biological traits. These findings were confirmed when repeating the analyses on large-ranged species, individual biogeographic regions and individual taxonomic groups. Climatic and human impacts have determined the extinction of mammal species in the past and are the main factors shaping the present distribution of mammals. These factors also affect other vertebrate groups globally, and their influence on range size may be similar as well. Measuring climatic and human variables can allow to obtain approximate range size estimations for data-deficient and newly discovered species (e.g. hundreds of mammal species worldwide). Our results support the need for a more careful consideration of the role of climate change and human impact - as opposed to species biological

  11. Experimental study of single-phase pressure drop and heat transfer in a micro-fin tube

    SciTech Connect

    Li, Xiao-Wei; Meng, Ji-An; Li, Zhi-Xin

    2007-11-15

    The single-phase pressure drop and heat transfer in a micro-fin tube were measured using oil and water as the working fluids. The Prandtl number varied from 3.2 to 220 and the Reynolds number ranged from 2500 to 90,000. The results show that there is a critical Reynolds number, Re{sub cr}, for heat transfer enhancement. For Remicro-fin tube is the same as that in a smooth tube, but for Reynolds numbers higher than Re{sub cr}, the heat transfer in the micro-fin tube is gradually enhanced compared with a smooth tube. It reaches more than twice that in a smooth tube for Reynolds numbers greater than 30,000 with water as the working fluid. The Nusselt number is proportional to Pr {sup 0.56} in the enhanced region and is proportional to Pr {sup 0.3} in the non-enhanced region. For the high Prandtl number working fluid (oil, 80< Pr <220), the critical Reynolds number for heat transfer enhancement is about 6000, while for the low Prandtl number working fluid (water, 3.2< Pr <5.8), the critical Reynolds number for heat transfer enhancement is about 10,000. The friction factors in the micro-fin tube are almost the same as for a smooth tube for Reynolds numbers below 10,000. For Reynolds numbers higher than 30,000, the friction factor is about 40-50% higher than for a smooth tube. (author)

  12. Controlled growth of copper oxide nanostructures by atmospheric pressure micro-afterglow

    NASA Astrophysics Data System (ADS)

    Altaweel, A.; Filipič, G.; Gries, T.; Belmonte, T.

    2014-12-01

    A large variety of copper oxide nanostructures encompassing nanodots, nanowires and nanowalls, sometimes organized in "cabbage-like" architectures, are grown locally by direct oxidation of copper thin films using the micro-afterglow of an Ar-O2 microwave plasma operating at atmospheric pressure. Morphology, structure and composition of the oxidized copper thin films are characterized by X-ray diffraction, secondary ion mass spectrometry and scanning electron microscopy. The concentric areas where each kind of nanostructures is found are defined by both their radial position with respect to the afterglow centre and by experimental conditions. A growth mechanism is proposed, based on stress-induced outward migration of copper ions. The development of stress gradients is caused by the formation of a copper oxide scale layer. If copper oxide nanowires can be grown as in thermal oxidation processes, micro-afterglow conditions offer novel nanostructures and nano-architectures.

  13. An atmospheric-pressure, high-aspect-ratio, cold micro-plasma

    PubMed Central

    Lu, X.; Wu, S.; Gou, J.; Pan, Y.

    2014-01-01

    An atmospheric pressure nonequilibrium Ar micro-plasma generated inside a micro-tube with plasma radius of 3 μm and length of 2.7 cm is reported. The electron density of the plasma plume estimated from the broadening of the Ar emission line reaches as high as 3 × 1016 cm−3. The electron temperature obtained from CR model is 1.5 ev while the gas temperature of the plasma estimated from the N2 rotational spectrum is close to room temperature. The sheath thickness of the plasma could be close to the radius of the plasma. The ignition voltages of the plasma increase one order when the radius of the dielectric tube is decreased from 1 mm to 3 μm. PMID:25502006

  14. Steady-State heat transfer through micro-channels in pressurized He II

    NASA Astrophysics Data System (ADS)

    Granieri, Pier Paolo; Baudouy, Bertrand; Four, Aurelian; Lentijo, F.; Mapelli, Alessandro; Petagna, P.; Tommasini, Davide

    2012-06-01

    The operation of the Large Hadron Collider superconducting magnets for current and high luminosity future applications relies on the cooling provided by helium-permeable cable insulations. These insulations take advantage of a He II micro-channels network constituting an extremely efficient path for heat extraction. In order to provide a fundamental understanding of the underlying thermal mechanisms, an experimental setup was built to investigate heat transport through single He II channels typical of the superconducting cable insulation network, where deviation from the macro-scale theory can appear. Micro-fabrication techniques were exploited to etch the channels down to a depth of ~ 16 ìm. The heat transport properties were measured in static pressurized He II and analyzed in terms of the laminar and turbulent He II laws, as well as in terms of the critical heat flux between the two regions.

  15. An atmospheric-pressure, high-aspect-ratio, cold micro-plasma

    NASA Astrophysics Data System (ADS)

    Lu, X.; Wu, S.; Gou, J.; Pan, Y.

    2014-12-01

    An atmospheric pressure nonequilibrium Ar micro-plasma generated inside a micro-tube with plasma radius of 3 μm and length of 2.7 cm is reported. The electron density of the plasma plume estimated from the broadening of the Ar emission line reaches as high as 3 × 1016 cm-3. The electron temperature obtained from CR model is 1.5 ev while the gas temperature of the plasma estimated from the N2 rotational spectrum is close to room temperature. The sheath thickness of the plasma could be close to the radius of the plasma. The ignition voltages of the plasma increase one order when the radius of the dielectric tube is decreased from 1 mm to 3 μm.

  16. Rate of the reaction of atomic hydrogen with propyne over an extended pressure and temperature range

    NASA Technical Reports Server (NTRS)

    Whytock, D. A.; Payne, W. A.; Stief, L. J.

    1976-01-01

    The technique of flash photolysis coupled with time resolved detection of H via resonance fluorescence has been used to obtain rate constants for the reaction of atomic hydrogen with propyne at temperatures from 215 to 460 K and at pressures in the range 5-600 torr. The rate constants are strongly pressure dependent and the high pressure limiting values give rise to the Arrhenius expression K = approximately 6 x 10 to the minus 11th exp(-2450T) cu cm per molecule per sec. The results are discussed and compared with those of previous studies

  17. Micro-Viscometer for Measuring Shear-Varying Blood Viscosity over a Wide-Ranging Shear Rate

    PubMed Central

    Kim, Byung Jun; Lee, Seung Yeob; Jee, Solkeun; Atajanov, Arslan; Yang, Sung

    2017-01-01

    In this study, a micro-viscometer is developed for measuring shear-varying blood viscosity over a wide-ranging shear rate. The micro-viscometer consists of 10 microfluidic channel arrays, each of which has a different micro-channel width. The proposed design enables the retrieval of 10 different shear rates from a single flow rate, thereby enabling the measurement of shear-varying blood viscosity with a fixed flow rate condition. For this purpose, an optimal design that guarantees accurate viscosity measurement is selected from a parametric study. The functionality of the micro-viscometer is verified by both numerical and experimental studies. The proposed micro-viscometer shows 6.8% (numerical) and 5.3% (experimental) in relative error when compared to the result from a standard rotational viscometer. Moreover, a reliability test is performed by repeated measurement (N = 7), and the result shows 2.69 ± 2.19% for the mean relative error. Accurate viscosity measurements are performed on blood samples with variations in the hematocrit (35%, 45%, and 55%), which significantly influences blood viscosity. Since the blood viscosity correlated with various physical parameters of the blood, the micro-viscometer is anticipated to be a significant advancement for realization of blood on a chip. PMID:28632151

  18. Micro-Viscometer for Measuring Shear-Varying Blood Viscosity over a Wide-Ranging Shear Rate.

    PubMed

    Kim, Byung Jun; Lee, Seung Yeob; Jee, Solkeun; Atajanov, Arslan; Yang, Sung

    2017-06-20

    In this study, a micro-viscometer is developed for measuring shear-varying blood viscosity over a wide-ranging shear rate. The micro-viscometer consists of 10 microfluidic channel arrays, each of which has a different micro-channel width. The proposed design enables the retrieval of 10 different shear rates from a single flow rate, thereby enabling the measurement of shear-varying blood viscosity with a fixed flow rate condition. For this purpose, an optimal design that guarantees accurate viscosity measurement is selected from a parametric study. The functionality of the micro-viscometer is verified by both numerical and experimental studies. The proposed micro-viscometer shows 6.8% (numerical) and 5.3% (experimental) in relative error when compared to the result from a standard rotational viscometer. Moreover, a reliability test is performed by repeated measurement (N = 7), and the result shows 2.69 ± 2.19% for the mean relative error. Accurate viscosity measurements are performed on blood samples with variations in the hematocrit (35%, 45%, and 55%), which significantly influences blood viscosity. Since the blood viscosity correlated with various physical parameters of the blood, the micro-viscometer is anticipated to be a significant advancement for realization of blood on a chip.

  19. Microfluidic analysis of pressure drop and flow behavior in hypertensive micro vessels.

    PubMed

    Hu, Ruiqing; Li, Fen; Lv, Jiaqi; He, Ying; Lu, Detang; Yamada, Takashi; Ono, Naoki

    2015-01-01

    The retinal arterial network is the only source of the highly nutrient-consumptive retina, thus any insult on the arteries can impair the retinal oxygen and nutrient supply and affect its normal function. The aim of this work is to study the influences of vascular structure variation on the flow and pressure characteristics via microfluidic devices. Two sets of micro-channel were designed to mimic the stenosed microvessels and dichotomous branching structure in the retinal arteries. Three working fluids including red blood cell (RBC) suspension were employed to investigate the pressure drop in the stenosed channel. The flow behaviors of RBC suspensions inside the micro channels were observed using high speed camera system. Pressure drop of different working fluids and RBC velocity profiles in the stenosed channel were obtained. Moreover, hematocrit levels of RBC suspensions inside the bifurcated channels were analyzed from the sequential images of RBC flow. The results of the flow in the stenosed channel show that RBCs drift from the center of the channels, and RBC velocity is influenced not only by the inlet flow rate but also the interaction between RBCs. The measured pressure drops in the stenosed channel increase notably with the increase of fluid viscosity. Furthermore, the dimensionless pressure drop due to the stenosis decreases with Reynolds number. On the other hand, the results of flow through the bifurcated channels show that as the ratio of the daughter-branch width to the mother-channel width increases, the ratio of hematocrit in two connected branches (Ht/Hd) decreases, which is in favorable agreement with the available analysis results.

  20. Energy harvesting from arterial blood pressure for powering embedded micro sensors in human brain

    NASA Astrophysics Data System (ADS)

    Nanda, Aditya; Karami, M. Amin

    2017-03-01

    This manuscript investigates energy harvesting from arterial blood pressure via the piezoelectric effect for the purpose of powering embedded micro-sensors in the human brain. One of the major hurdles in recording and measuring electrical data in the human nervous system is the lack of implantable and long term interfaces that record neural activity for extended periods of time. Recently, some authors have proposed micro sensors implanted deep in the brain that measure local electrical and physiological data which are then communicated to an external interrogator. This paper proposes a way of powering such interfaces. The geometry of the proposed harvester consists of a piezoelectric, circular, curved bimorph that fits into the blood vessel (specifically, the Carotid artery) and undergoes bending motion because of blood pressure variation. In addition, the harvester thickness is constrained such that it does not modify arterial wall dynamics. This transforms the problem into a known strain problem and the integral form of Gauss's law is used to obtain an equation relating arterial wall motion to the induced voltage. The theoretical model is validated by means of a Multiphysics 3D-FEA simulation comparing the harvested power at different load resistances. The peak harvested power achieved for the Carotid artery (proximal to Brain), with PZT-5H, was 11.7 μW. The peak power for the Aorta was 203.4 μW. Further, the variation of harvested power with variation in the harvester width and thickness, arterial contractility, and pulse rate is investigated. Moreover, potential application of the harvester as a chronic, implantable and real-time Blood pressure sensor is considered. Energy harvested via this mechanism will also have applications in long-term, implantable Brain Micro-stimulation.

  1. A study on the inactivation of micro-organisms and enzymes by high pressure CO2.

    PubMed

    Bertoloni, Giulio; Bertucco, Alberto; De Cian, Veronica; Parton, Tiziana

    2006-09-05

    This study addresses some microbial inactivation phenomena induced by high pressure CO2 over micro-organisms and enzymes. The activity of four selected enzymes was measured before and after treatment with CO2 under pressure in both buffer solutions and natural cellular environment (E. coli cells and tomato paste). Results are reported for acid phosphatase, alkaline phosphatase, ATPase, and pectinase at different conditions of temperature, CO2 pressure, and treatment time (32-40 degrees C, 85-150 bar, 30-70 min). The results obtained show that the high pressure CO2 treatment induces an inactivation of cellular enzymatic activity higher than the one caused on the same enzymes in solution. However, the measured activity difference is not caused by a damage at the enzymes molecular level but is a consequence of the permeabilization of the cellular envelopes which leads to a release of unmodified enzymes from the cells with simultaneous drop of enzymatic cellular activity. The reported data suggest that the bacterial cell death is probably due not to a selective effect of high pressure CO2 treatment but to simultaneous detrimental action of CO2 on cellular membrane and cell wall.

  2. Short range micro-power impulse radar with high resolution swept range gate with damped transmit and receive cavities

    DOEpatents

    McEwan, T.E.

    1998-06-30

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with atypical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. 20 figs.

  3. Short range micro-power impulse radar with high resolution swept range gate with damped transmit and receive cavities

    DOEpatents

    McEwan, Thomas E.

    1998-01-01

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with atypical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings.

  4. A pressurized ion chamber monitoring system for environmental radiation measurements utilizing a wide-range temperature-compensated electrometer

    SciTech Connect

    Stevenick, W. Van . Environmental Measurements Lab.)

    1994-08-01

    The performance of a complete pressurized ion chamber (PIC) radiation monitoring system is described. The design incorporates an improved temperature-compensated electrometer which is stable to [+-]3 [center dot] 10[sup [minus]16] A over the environmental range of temperature ([minus]40 to +40 C). Using a single 10[sup 11] [Omega] feed-back resistor, the electrometer accurately measures currents over a range from 3 [center dot] 10[sup [minus]15] A to 3 [center dot] 10[sup [minus]11] A. While retaining the sensitivity of the original PIC system (the instrument responds readily to small background fluctuations on the order of 0.1 [mu]R h[sup [minus]1]), the new system measures radiation levels up to the point where the collection efficiency of the ion chamber begins to drop off, typically [approximately]27 pA at 1 mR h[sup [minus]1]. A data recorder and system controller was designed using the Tattletale[trademark] Model 4A computer. Digital data is stored on removable solid-state, credit-card style memory cards.

  5. [Effect of dynamic high-pressure micro-fluidization on the structure of maize amylose].

    PubMed

    Tu, Zong-Cai; Yin, Yue-Bin; Zhang, Qiu; Wang, Hui

    2013-05-01

    The effect of dynamic high-pressure micro-fluidization (DHPM) at 80, 120, 160, and 200 MPa on the structure of maize amylose was investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), Xray diffraction, and FT-IR spectroscopy. SEM analysis showed that the surface appearances of maize amylose were altered and the starch granules were partially congregated together after DHPM treatment. AFM images showed that the treated starch molecules are cross-linked to each other and arranged in a close mesh structure. Xray diffraction spectra and IR spectra indicated that relative crystallinity declined gradually with the pressure increasing. The results provide a theoretical basis for starch modification of DHPM.

  6. An approach to improving transporting velocity in the long-range ultrasonic transportation of micro-particles

    SciTech Connect

    Meng, Jianxin; Mei, Deqing Yang, Keji; Fan, Zongwei

    2014-08-14

    In existing ultrasonic transportation methods, the long-range transportation of micro-particles is always realized in step-by-step way. Due to the substantial decrease of the driving force in each step, the transportation is lower-speed and stair-stepping. To improve the transporting velocity, a non-stepping ultrasonic transportation approach is proposed. By quantitatively analyzing the acoustic potential well, an optimal region is defined as the position, where the largest driving force is provided under the condition that the driving force is simultaneously the major component of an acoustic radiation force. To keep the micro-particle trapped in the optimal region during the whole transportation process, an approach of optimizing the phase-shifting velocity and phase-shifting step is adopted. Due to the stable and large driving force, the displacement of the micro-particle is an approximately linear function of time, instead of a stair-stepping function of time as in the existing step-by-step methods. An experimental setup is also developed to validate this approach. Long-range ultrasonic transportations of zirconium beads with high transporting velocity were realized. The experimental results demonstrated that this approach is an effective way to improve transporting velocity in the long-range ultrasonic transportation of micro-particles.

  7. Evaluation of micro tip pressure transducers for the measurement of intracerebral pressure transients induced by fluid percussion.

    PubMed

    Walter, B; Bauer, R; Fritz, H; Jochum, T; Wunder, L; Zwiener, U

    1999-02-01

    We describe the application of MIKRO TIP miniature pressure transducers (MPT) for the in vivo measurement of intracerebral stresses induced by traumatic brain injury (TBI). In order to test the linearity of these transducers pressure pulses of different amplitudes (duration approximately 10ms) were generated in a closed calibration chamber. A piezoelectric pressure transducer (PPT) served as the reference measure. A linear correlation was found within the pressure range between 0.57 and 5.09 bar (R2 = 0.998). The frequency transmission characteristics of the MPTs are comparable to the PPT. In three juvenile swines (6 weeks of age) pressures within the brain tissue were induced by fluid percussion (FP) and were measured in the anterior, middle, and posterior cranial cavity as well as in the extracranial part of the medulla oblongata. The data obtained in our experiments agree with the basic biomechanics of FP known from studies in cats and rabbits. Due to their small size, MPTs can be applied in living animals. Stereotaxic positioning of these catheters at any site of the brain and spinal cord requires only minimal surgery. Therefore, MPTs are useful in evaluating animal models of brain injury and in generating input data for computational models of head injury as well as to validate the mathematical results of such models with experimental data.

  8. An investigation into the potential hypoalgesic effects of different amplitudes of PA mobilisations on the lumbar spine as measured by pressure pain thresholds (PPT).

    PubMed

    Krouwel, Oliver; Hebron, Clair; Willett, Elaine

    2010-02-01

    Mobilisation of the spine is a common technique used in clinical practice. Studies have shown that mobilisation to the spine can decrease pain. The optimum treatment dose for achieving this has not so far been investigated. Previous studies that demonstrate the pain relieving effects of mobilisations have used large amplitude of oscillations. The importance of amplitude on pain relief has not been established. The current study aims to: a) Investigate the importance of amplitude as part of the treatment dose. b) To explore the extent of any pain reliving effects seen following mobilisations. The study employed a randomised, single blind, within-subjects repeated measure design. Thirty asymptomatic subjects participated. The subjects completed three experimental conditions on three separate occasions. The conditions were: large amplitude of oscillations (forces between 50 and 200N), small amplitude of oscillations (150N-200N) and quasi-static (maintained at 200N). Each condition involved a 3x1minute central PA mobilisation at a frequency of 1.5Hz on the lumbar spine. Pressure pain thresholds (PPT) were measured immediately before and after each intervention at 4 different sites. The sites were chosen to determine the extent of the hypoalgesic response. Results demonstrated a significant increase in PPT following lumbar mobilisations (p=0.013) at all measured sites. However, no significant difference was found between amplitude conditions (p=0.864). This study suggests that in asymptomatic subjects a systemic hypoalgesic response is caused by lumbar mobilisation regardless of amplitude.

  9. Effect of Knudsen thermal force on the performance of low-pressure micro gas sensor

    NASA Astrophysics Data System (ADS)

    Barzegar Gerdroodbary, M.; Ganji, D. D.; Taeibi-Rahni, M.; Vakilipour, Shidvash

    2017-07-01

    In this paper, Direct Simulation Monte Carlo (DSMC) simulations were applied to investigate the mechanism of the force generation inside a low-pressure gas sensor. The flow feature and force generation mechanism inside a rectangular enclosure with heat and cold arms as the non-isothermal walls are comprehensively explained. In addition, extensive parametric studies are done to study the effects of physical parameters on the performance and characteristics of this device in different operating conditions. In this research, the Knudsen number is varied from 0.1 to 4.5 (0.5 to 11torr) to reveal all the characteristics of the thermally driven force inside the MEMS sensor. In order to simulate a rarefied gas inside the micro gas detector, Boltzmann equations are applied to obtain high-precision results. The effects of ambient pressure and temperature difference of arms are comprehensively investigated. Our findings show that maximum force increases more than 7 times when the temperature difference of the cold and hot arms is increased from 10 to 100K. In addition, the results demonstrate that the thermal gradient at rarefied pressure induces complex structure, and the mechanism of force generation highly varies at different pressure conditions.

  10. Effect of Chamber Pressure on the Vibrational Properties of Micro- and Nano-Cantilevers

    NASA Astrophysics Data System (ADS)

    Keskar, Gayatri; Gaillard, Jay; Taylor, Jonathan; Skove, Malcolm; Rao, Apparao

    2007-03-01

    We have studied the nonlinear dynamics of micro- and nano-cantilevers under varying ambient conditions using the Harmonic Detection of Resonance technique (HDR)^1. In our studies, a cantilever is either microstructure shaped like a diving board, or a cantilevered MWNT. In this work, we report the dependence of the amplitude and Q of a silicon microcantilever (300 μm long, 35 μm wide, 2 μm thick) on ambient pressure. An environment of air at a pressure of 10-3 Torr gives a high quality factor of ˜7000. The response of higher harmonics of the ac voltage that drives the cantilever is also observed with varying chamber pressure. An investigation of the influence of ac and dc voltages on sensitivity shows very good agreement with a model calculation. The shift in the resonant frequency of cantilevers under different environments such as helium, air and argon at different pressures will be discussed. References: 1. J. Gaillard, M. J. Skove, R. Ciocan, and A. M. Rao, Rev. Sci. Instrum. 77, 073907 (2006). Contact Info: arao@clemson.edu

  11. Diagnosis of oscillating pressure-driven flow in a microdiffuser using micro-PIV

    NASA Astrophysics Data System (ADS)

    Sun, Chen-Li; Lee, Hung-Chien; Kao, Ran-Xing

    2012-01-01

    In this study, the characteristics of oscillating pressure-driven flow in a microdiffuser are examined by μPIV (micro Particle Image Velocimetry) diagnostics. Utilizing a cam-follower system, a dynamic pressure generator is built in-house to provide a time-varying sinusoidal pressure source. Three parameters are examined experimentally: the excitation frequency, the cam size, and the half-angle of the microdiffuser. Driven by oscillating pressure, we find that there exists an optimal half-angle such that maximum net flow is attained in the expansion direction. Contrarily to the prediction of hydraulics theory which only considers steady flow, flow in the microdiffuser of the optimal half-angle does not necessarily remain attached. Rather, maximum net flow can also occur in microdiffusers where vortices retain a slender shape. When vortex bubbles are slender, the μPIV results reveal that the core flow accelerates to a higher forward velocity during the first half of the cycle and flow rectification is actually enhanced. Due to the three-dimensional flow structure, fluid is drawn out of the vortices near the reattachment point to join the core flow and consequently magnifies the forward flow. As the half-angle increases, vortices become rounder and the core flow is drastically narrowed to reduce flow rectification.

  12. The electron spectro-microscopy beamline at National Synchrotron Light Source II: A wide photon energy range, micro-focusing beamline for photoelectron spectro-microscopies

    SciTech Connect

    Reininger, R.; Hulbert, S. L.; Chubar, O.; Vescovo, E.; Johnson, P. D.; Valla, T.; Sadowski, J. T.; Starr, D. E.

    2012-02-15

    A comprehensive optical design for a high-resolution, high-flux, wide-energy range, micro-focused beamline working in the vacuum ultraviolet and soft x-ray photon energy range is proposed. The beamline is to provide monochromatic radiation to three photoelectron microscopes: a full-field x-ray photoelectron emission microscope and two scanning instruments, one dedicated to angle resolved photoemission spectroscopy ({mu}-ARPES) and one for ambient pressure x-ray photoelectron spectroscopy and scanning photoelectron microscopy (AP-XPS/SPEM). Microfocusing is achieved with state of the art elliptical cylinders, obtaining a spot size of 1 {mu}m for ARPES and 0.5 {mu}m for AP-XPS/SPEM. A detailed ray tracing analysis quantitatively evaluates the overall beamline performances.

  13. Scale of the equilibration volume in eclogites: insights from a new micro-mapping approach - Example of Atbashi range, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Loury, Chloé; Lanari, Pierre; Rolland, Yann; Guillot, Stéphane; Ganino, Clément

    2014-05-01

    Understanding geodynamic processes in subduction zones and mountains belts relies on the reconstruction of precise pressure-temperature paths (P-T paths) from metamorphic rocks. Most P-T paths are obtained using quantitative thermobarometry such as forward thermodynamics models. The question of the scale of the equilibration volume is of prime importance because its chemistry is used as input for the calculation of P-T sections. In chemically homogeneous rocks the bulk rock may be obtained either by ICP-MS or XRF analysis on whole rocks. For chemically heterogeneous rocks, containing different mineral assemblages and/or a high proportion of zoned minerals, the concept of local effective bulk (LEB) is essential. In the last 10 years, X-ray micro-mapping methods have been developed in this aim. Here we show how standardized X-ray maps can be used to estimate the equilibration volume at the pressure peak in an eclogite sample. The study area lies in the Atbashi range, in Kyrgyzstan, along the South-Tianshan carboniferous suture of the Central Asian Orogenic Belt with the Tarim block. We use the micro-mapping approach to unravel the P-T path of a mafic eclogite containing mm-scale garnet porphyroblasts. Quantitative compositional maps of a garnet and its surrounding matrix are obtained from standardized X-ray maps processed with the XMapTools program (Lanari et al, 2014). By using these maps we measured the LEB corresponding to the different stages of garnet growth. The equilibration volume is then modeled using the local compositions (extrapolated in 3D) combined with Gibbs free energy minimization. Our model suggests that equilibrium conditions are attained for chemistry made of 90% of garnet and 10% of matrix. P-T sections are calculated from the core of the garnet to the rim taking into account the fractionation at each stage of garnet growth by changing the bulk composition. We obtained the following P-T path: (1) garnet core crystallization during prograde stage

  14. Nanotopographic characterization of spotted micro arrays on polyvinyl alcohol films by high-resolution long-range nanoprofiling.

    PubMed

    Thete, Aniket R; Gross, G Alexander; Hausotte, Tino; Jäger, Gerd; Dorozhovets, Nataliya; Köhler, J Michael

    2009-01-01

    The nanopositioning and nanomeasuring machine was applied for the nanotopographic characterization of polymer micro spot arrays of fluorimetric chemochips. Chemochips are arrays of fluorescence dyes in a hydrogel matrix with different response behaviors of chemical components determination of chemical and physico-chemical properties of analytes by a pattern recognition approach. For the characterization and quality control of the spots, a nanometer resolution is needed over a scan range of several millimeters. This challenge could be met by use of a scanning probe sensor in connection with a laser interferometer controlled high-precision positioning and measuring device. This way, topographic scans with the resolution of atomic force microscope could be achieved over these demandingly large ranges. The technique was used in order to determine the quality of thin film micro spots made from fluorescence dye solutions on preformed polymer films and also tested for characterization of monomolecular films in the form of micro spots. The nanotopographic measurements reflect the strong influence of solvent/matrix interaction, wetting, swelling and material transport during the application of picoliter droplets in the spotting process. The measurement clarifies the reason for the formation of roughness in the nanometer range by nano-crystal formation in the upper part of polymer film and the rim formation of micro spots during solvent evaporation. The studies show the effect of application of different numbers of droplets in a dispensing series for spot formation and prove the high importance of polymer/solvent interaction for the quality of formed micro spots as well as for spot arrays of monomolecular films. Copyright (c) 2009 Wiley Periodicals, Inc.

  15. A low-power tool for measuring acceleration, pressure, and temperature (APT) with wide dynamic range and bandwidth

    NASA Astrophysics Data System (ADS)

    Heesemann, Martin; Davis, Earl E.; Paros, Jerome; Johnson, Greg; Meldrum, Robert; Scherwath, Martin; Mihaly, Steven

    2017-04-01

    We present a new tool that facilitates the study of inter-related geodetic, geodynamic, seismic, and oceanographic phenomena. It incorporates a temperature compensated tri-axial accelerometer developed by Quartz Seismic Sensors, Inc., a pressure sensor built by Paroscientific Inc., and a low-power, high-precision frequency counter developed by Bennest Enterprises Ltd. and built by RBR, Ltd. The sensors are housed in a 7 cm o.d. titanium pressure case designed for use to full ocean depths (withstands more than 20 km of water pressure). Sampling intervals are programmable from 0.08 s to 1 hr; standard memory can store up to 130 million samples; total power consumption is roughly 115 mW when operating continuously and proportionately lower when operating intermittently (e.g., 2 mW average at 1 sample per min). Serial and USB communications protocols allow a variety of autonomous and cable-connection options. Measurement precision of the order of 10-8 of full scale (e.g., pressure equivalent to 4000 m water depth, acceleration = +/- 3 g) allows observations of pressure and acceleration variations of 0.4 Pa and 0.3 μm s-2. Long-term variations in vertical acceleration are sensitive to displacement through the gravity gradient down to a level of roughly 2 cm, and variations in horizontal acceleration are sensitive to tilt down to a level of 0.03 μrad. With the large dynamic ranges, high sensitivities and broad bandwidth (6 Hz to DC), ground motion associated with microseisms, strong and weak seismic ground motion, tidal loading, and slow and rapid geodynamic deformation - all normally studied using disparate instruments - can be observed with a single tool. Installation in the marine environment is accomplished by pushing the tool roughly 1 m vertically below the seafloor with a submersible or remotely operated vehicle, with no profile remaining above the seafloor to cause current-induced noise. The weight of the tool is designed to match the sediment it displaces to

  16. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors

    PubMed Central

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

    2015-01-01

    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 nmkPa and a resolution of better than ΔP = 10 Pa (0.1 cm H2O). A static pressure test in 38 cmH2O 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 pmK, 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. PMID:26184331

  17. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors.

    PubMed

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

    2015-07-13

    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.

  18. Pressure gradient sensors for bearing determination in shallow water tracking ranges

    NASA Astrophysics Data System (ADS)

    Stein, Peter J.; Euerle, Steven E.; Menoche, Richard K.; Janiesch, Robert E.

    1996-04-01

    Underwater acoustic tracking has traditionally used only the arrival time of tracking pings to localize targets. This implies that the ping transmitted from a target must be received at a minimum of three separate nodes (receiver locations) in order to determine the position. For deep water ranges this was acceptable. In shallow water, where propagation ranges are limited, this requires a large number of nodes. This makes shallow water ranges very costly. An effort is underway to use pressure gradient hydrophones as receivers and measure the bearing of the ping arrival along with arrival time, thereby locating the target using only one tracking node. This allows for increased node spacing and greatly reduced cost. However, the accuracy required for training ranges is on the order of 1 degree. Further, the directional receiver must be housed so as to withstand impacts from fishing operations. Research including design, fabrication, and testing of conventional and unconventional pressure gradient hydrophones, the housing, and signal processing methods are discussed. Extensive testing has already been conducted using a 1″ diameter by 5″ long multimode hydrophone. A shallow water tracking test was conducted at the NUWC Lake Seneca test facility. The results demonstrate the feasibility of tracking using a single pressure gradient hydrophone with an accuracy of 50 yds out to 2 kyds. The effects of multiple paths and scattering are also discussed.

  19. Creep- and fatigue-resistant, rapid piezoresistive responses of elastomeric graphene-coated carbon nanotube aerogels over a wide pressure range.

    PubMed

    Tsui, Michelle N; Islam, Mohammad F

    2017-01-19

    Lightweight, flexible piezoresistive materials with wide operational pressure ranges are in demand for applications such as human physical activity and health monitoring, robotics, and for functional interfacing between living systems and wearable electronics. Piezoresistivity of many elastomeric foams of polymers and carbon allotropes satisfies much of the required characteristics for these applications except creep and fatigue resistance due to their viscoelasticity, critically limiting the reliability and lifetime of integrated devices. We report the piezoresistive responses from aerogels of graphene-coated single-walled carbon nanotubes (SWCNTs), made using a facile and versatile sol-gel method. Graphene crosslinks the junctions of the underlying random network of SWCNTs, generating lightweight elastomeric aerogels with a mass density of ≈11 mg mL(-1) (volume fraction ≈7.7 × 10(-3)) and a Young's modulus of ≈0.4 MPa. The piezoresistivity of these aerogels spans wide compressive pressures up to at least 120 kPa with sensitivity that exhibit ultrafast temporal responses of <27 ms and <3% delay ratio over 10(4) compressive loading-unloading cycles at rates between 0.1-10 Hz. Most importantly, the piezoresistive responses do not show any creep at least for 1 hour and 80 kPa of compressive static loading. We suggest that the fatigue- and creep-resistant, ultrafast piezoresistive responses of these elastomeric aerogels are highly attractive for use in dynamic and static lightweight, pressure sensing applications such as human activity monitoring and soft robotics.

  20. Temperature dependence of the anisotropic deformation of Zr-2.5%Nb pressure tube material during micro-indentation

    NASA Astrophysics Data System (ADS)

    Bose, B.; Klassen, R. J.

    2011-12-01

    The effect of temperature on the anisotropic plastic deformation of textured Zr-2.5%Nb pressure tube material was studied using micro-indentation tests performed in the axial, radial, and transverse directions of the tube over the temperature range from 25 to 400 °C. The ratio of the indentation stress in the transverse direction relative to that in the radial and axial directions was 1.29:1 and 1.26:1 at 25 °C but decreased to 1.22:1 and 1.05:1 at 400 °C. The average activation energy of the obstacles that limit the rate of indentation creep increases, from 0.72 to 1.33 eV, with increasing temperature from 25 to 300 °C and is independent of indentation direction. At temperature between 300 °C and 400 °C the measured activation energy is considerably reduced for indentation creep in the transverse direction relative to that of either the axial or radial directions. We conclude that, over this temperature range, the strength of the obstacles that limit the time-dependent dislocation glide on the pyramidal slip system changes relative to that on the prismatic slip system. These findings provide new data on the temperature dependence of the yield stress and creep rate, particularly in the radial direction, of Zr-2.5%Nb pressure tubes and shed new light on the effect of temperature on the operation of dislocation glide on the prismatic and pyramidal slip systems which ultimately determines the degree of mechanical anisotropy in the highly textured Zr-2.5Nb pressure tube material used in CANDU nuclear reactors.

  1. Micro structure of gas-hydrate sediment: in situ sub-sampling from pressured sedimental samples

    NASA Astrophysics Data System (ADS)

    Jin, Y.; Konno, Y.; Yoneda, J.; Egawa, K.; Kida, M.; Ito, T.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

    2013-12-01

    Porosity of gas-hydrate bearing sediment is a key of gas production efficient from natural gas-hydrate reservoir. Developable natural gas-hydrates by conventional gas/oil production apparatus almost exist in unconsolidated sedimental layer. Because in situ evaluation of porosity with hydrate in pores is difficult, porosity values were discussed from hydrate bearing sediment quenched by liquid nitrogen. In the case of quenched sample, sand matrix in GH sediments could have been changed by freezing water in pores. Therefore, porosity data in previous reports may be over estimated comparing with nature of sediments at in situ condition. We developed in situ sub-sampling system for pressured natural gas-hydrate sediments. A small sedimental piece can be sampled from pressured gas hydrate sediments without pressure-release to atmosphere by using the our developed apparatus. In this presentation, we demonstrated sub-sampling from an artificial gas-hydrate sediment and measured micro-scale structure of the sub-sampled gas-hydrate sedimental piece. This work was supported by funding from the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) planned by the Ministry of Economy, Trade and Industry (METI), Japan.

  2. Modified quadrupole mass analyzer RGA-100 for beam plasma research in forevacuum pressure range

    SciTech Connect

    Zolotukhin, D. B.; Tyunkov, A. V.; Yushkov, Yu. G.; Oks, E. M.

    2015-12-15

    The industrial quadrupole RGA-100 residual gas analyzer was modified for the research of electron beam-generated plasma at forevacuum pressure range. The standard ionizer of the RGA-100 was replaced by three electrode extracting unit. We made the optimization of operation parameters in order to provide the maximum values of measured currents of any ion species. The modified analyzer was successfully tested with beam plasma of argon, nitrogen, oxygen, and hydrocarbons.

  3. Isentropic expansion of copper plasma in Mbar pressure range at "Luch" laser facility

    NASA Astrophysics Data System (ADS)

    Bel'kov, S. A.; Derkach, V. N.; Garanin, S. G.; Mitrofanov, E. I.; Voronich, I. N.; Fortov, V. E.; Levashov, P. R.; Minakov, D. V.

    2014-01-01

    We present experimental results on thermodynamic properties of dense copper plasma in Mbar pressure range. The laser facility "Luch" with laser intensity 1014 W/cm2 is used to compress copper up to ˜8 Mbar by a strong shock wave; subsequent expansion of copper plasma into Al, Ti, Sn allows us to obtain release isentropes of copper by the impedance-matching method. A theoretical analysis and quantum simulations show that in our experiments strongly coupled quantum plasma is generated.

  4. Transformations in the Medium-Range Order of Fused Silica under High Pressure

    NASA Astrophysics Data System (ADS)

    Dávila, Lílian P.; Caturla, Maria-José; Kubota, Alison; Sadigh, Babak; Díaz de La Rubia, Tomás; Shackelford, James F.; Risbud, Subhash H.; Garofalini, Stephen H.

    2003-11-01

    Molecular dynamics simulations of fused silica at shock pressures reproduce the experimental equation of state of this material and explain its characteristic shape. We demonstrate that shock waves modify the medium-range order of this amorphous system, producing changes that are only clearly revealed by its ring size distribution. The ring size distribution remains practically unchanged during elastic compression but varies continuously after the transition to the plastic regime.

  5. Time evolution of diameter of micro-bubbles generated by a pressurized dissolution method

    NASA Astrophysics Data System (ADS)

    Ishii, Kazuya; Fujimoto, Shudai; Hosokawa, Shigeo; Tomiyama, Akio; Ito, Yoshihiro; Maeda, Yasunari

    2014-04-01

    Size distributions of micro-bubbles and concentrations of dissolved oxygen in water in a square duct downstream of the decompression nozzle were measured to investigate the time evolution of bubble diameter and the mass transfer of dissolved gas between bubbles and water after bubble generation in a pressurized dissolution method. A numerical simulation based on the Rayleigh-Plesset equation was also carried out to predict time evolutions of bubble diameter and concentration of dissolves gas. The validity of the prediction was discussed through the comparison between the predictions and the experiments. As a result, the following conclusions were obtained: (1) When cavitation does not occur in the decompression nozzle, few micro-bubbles are generated at the nozzle and the mass transfer rate between bubbles and water in the downstream region of the nozzle is low due to a low interface area concentration. The mass transfer due to bubble nucleation is negligibly small in the downstream region of the decompression nozzle in spite of the supersaturated concentration of the dissolved gas. (2) When cavitation occurs in the nozzle, a lot of micro-bubbles are generated at the nozzle and therefore, the mass transfer rate between the phases becomes high. Hence, the bubble diameter and the void fraction increase and the concentration of dissolved gas in water decreases with the time elapsed after the bubble generation. (3) The proposed numerical method can reasonably predict time evolution of bubble size distributions, void fractions and concentrations of dissolved gas, provided that a reliable initial condition is available. Since the numerical simulation assumes that no bubble nucleation occurs in the downstream region of the nozzle, the agreement between the prediction and the experiments proves low influence of the bubble nucleation on the mass transfer between the phases.

  6. Two-phase pressure drop across a hydrofoil-based micro pin device using R-123

    SciTech Connect

    Kosar, Ali

    2008-05-15

    The two-phase pressure drop in a hydrofoil-based micro pin fin heat sink has been investigated using R-123 as the working fluid. Two-phase frictional multipliers have been obtained over mass fluxes from 976 to 2349 kg/m{sup 2} s and liquid and gas superficial velocities from 0.38 to 1.89 m/s and from 0.19 to 24 m/s, respectively. It has been found that the two-phase frictional multiplier is strongly dependent on flow pattern. The theoretical prediction using Martinelli parameter based on the laminar fluid and laminar gas flow represented the experimental data fairly well for the spray-annular flow. For the bubbly and wavy-intermittent flow, however, large deviations from the experimental data were recorded. The Martinelli parameter was successfully used to determine the flow patterns, which were bubbly, wavy-intermittent, and spray-annular flow in the current study. (author)

  7. Quantitative measurements of ground state atomic oxygen in atmospheric pressure surface micro-discharge array

    NASA Astrophysics Data System (ADS)

    Li, D.; Kong, M. G.; Britun, N.; Snyders, R.; Leys, C.; Nikiforov, A.

    2017-06-01

    The generation of atomic oxygen in an array of surface micro-discharge, working in atmospheric pressure He/O2 or Ar/O2 mixtures, is investigated. The absolute atomic oxygen density and its temporal and spatial dynamics are studied by means of two-photon absorption laser-induced fluorescence. A high density of atomic oxygen is detected in the He/O2 mixture with up to 10% O2 content in the feed gas, whereas the atomic oxygen concentration in the Ar/O2 mixture stays below the detection limit of 1013 cm-3. The measured O density near the electrode under the optimal conditions in He/1.75% O2 gas is 4.26  ×  1015 cm-3. The existence of the ground state O (2p 4 3 P) species has been proven in the discharge at a distance up to 12 mm away from the electrodes. Dissociative reactions of the singlet O2 with O3 and deep vacuum ultraviolet radiation, including the radiation of excimer \\text{He}2\\ast , are proposed to be responsible for O (2p 4 3 P) production in the far afterglow. A capability of the surface micro-discharge array delivering atomic oxygen to long distances over a large area is considered very interesting for various biomedical applications.

  8. Probe measurements of electron energy spectrum in Helium/air micro-plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.; Hensley, A. L.; Tolson, B. A.

    2016-09-01

    It is experimentally demonstrated that a wall probe may be a useful instrument for interpretation of electron energy spectrum in a micro-plasma with a nonlocal electron distribution function at atmospheric pressure. Two micro-plasma devices were fabricated with three layers of molybdenum metal foils with thickness of 0.1 mm separated by two sheets of mica insulation with thickness of 0.11 mm. In one device a hole with the diameter of 0.2 mm formed a cylindrical discharge cavity that passed through the entire five layers. In the second device the hole has the diameter of 0.065 mm. In both devices the inner molybdenum layer formed a wall probe, while the outer layers of molybdenum served as the hollow cathode and anode. The discharge was open into air with flow of helium gas. It is found that the wall probe I-V trace is sensitive to the presence of helium metastable atoms. The first derivative of the probe current with respect to the probe potential shows peaks revealing fast electrons at specific energies arising due to plasma chemical reactions. The devices may be applicable for developing analytical sensors for extreme environments, including high radiation and vibration levels and high temperatures. This work was performed while VID held a NRC Research Associateship Award at AFRL.

  9. Tuning the sensing range of silicon pressure sensor by trench etching technology

    NASA Astrophysics Data System (ADS)

    Chou, Yu-Tuan; Lin, Hung-Yi; Hu, Hsin-Hua

    2006-01-01

    The silicon pressure sensor has been developed for over thirty years and widely used in automobiles, medical instruments, commercial electronics, etc. There are many different specifications of silicon pressure sensors that cover a very large sensing range, from less than 1 psi to as high as 1000 psi. The key elements of the silicon pressure sensor are a square membrane and the piezoresistive strain gages near the boundary of the membrane. The dimensions of the membrane determine the full sensing range and the sensitivity of the silicon sensor, including thickness and in-plane length. Unfortunately, in order to change the sensing range, the manufacturers need to order a customized epi wafer to get the desired thickness. All masks (usually six) have to be re-laid and re-fabricated for different membrane sizes. The existing technology requires at least three months to deliver the prototype for specific customer requests or the new application market. This research proposes a new approach to dramatically reduce the prototyping time from three months to one week. The concept is to tune the rigidity of the sensing membrane by modifying the boundary conditions without changing the plenary size. An extra mask is utilized to define the geometry and location of deep-RIE trenches and all other masks remain the same. Membranes with different depths and different patterns of trenches are designed for different full sensing ranges. The simulation results show that for a 17um thick and 750um wide membrane, the adjustable range by tuning trench depth is about 45% (from 5um to 10um), and can go to as high as 100% by tuning both the pattern and depth of the trenches. Based on an actual test in a product fabrication line, we verified that the total delivery time can be minimized to one week to make the prototyping very effective and cost-efficient.

  10. Micro-texture and Structure of High-pressure Quenched Graphite and Related Carbon Materials

    NASA Astrophysics Data System (ADS)

    Ohfuji, H.; Aibara, K.; Sumiya, H.; Irifune, T.

    2007-12-01

    There have been extensive studies in room-temperature compression of graphite and related carbon materials such as nanotubes and fullerene. Some reports claimed that the transformation of carbon hybridized state from sp2 to sp3 takes place under high pressure at room temperature, and the hardness of the quench products may be comparable to that of cubic diamond. Here, we investigated the micro-texture and structure involved in such high-pressure quenched carbon materials using high-resolution electron microscopy. High- pressure experiments were conducted on a variety of carbon materials including graphite (synthetic, highly- oriented sheet), single/multi-walled carbon nanotubes, amorphous carbons in a diamond anvil cell (DAC, with 250 μm culet non-beveled anvils) at room temperature. Pelletized sample was loaded into a 70 μm hall, drilled in a preindented Re gasket, without a pressure medium. The sample was compressed up to 70 ~ 90 GPa at room temperature, kept at the highest pressure at least overnight, and then decompressed. The pressure dependence of graphite E2g( G) Raman band at ~1580cm-1 was measured on compression and decompression. A1g( D) band, so called defect band at ~1350 cm-1, was also collected for the recovered products. The quenched materials were examined by high-resolution (HR) field emission (FE-) SEM and (HR)TEM. A focused ion beam (FIB) was employed to fabricate thin cross-sections of the samples. The most notable change in texture upon compression was observed in multi-walled carbon nanotube (MWNT); the elongated tubes were fragmented into short rods (ca. 100 - 300 nm in length and 80 - 100 nm in width, almost two times wider than that of the original MWNT). TEM observations showed that the short rod- shaped particles consist of piles of graphene shells (stacked walls of MWNT, characterized by (002) lattice fringes) which were significantly bent and fragmented. Some of those rod-shaped particles showed lattice fringes with an interlayer

  11. Fabrication and characterization of 3C-silicon carbide micro sensor for wireless blood pressure measurements

    NASA Astrophysics Data System (ADS)

    Basak, Nupur

    A potentially implantable single crystal 3C-SiC pressure sensor for blood pressure measurement was designed, simulated, fabricated, characterized and optimized. This research uses a single crystal 3C-SiC, for the first time, to demonstrate its application as a blood pressure measurement sensor. The sensor, which uses the epitaxial grown 3C-SiC membrane to measure changes in pressure, is designed to be wireless, biocompatible and linear. The SiC material was chosen for its superior physical, chemical and mechanical properties; the capacitive sensor uses a 3C-SiC membrane as one of the electrodes; and, the sensor system is wireless for comfort and to allow for convenient reading of real-time pressure data (wireless communication is enabled by connecting the sensor parallel to a planar inductor). Together, the variable capacitive sensor and planar inductor create a pressure sensitive resonant circuit. The sensor system described above allows for implantation into a human patient's body, after which the planar inductor can be coupled with an external inductor to receive data for real-time blood pressure measurement. Electroplating, thick photo-resist characterization, RIE etching, oxidation, CVD, chemical mechanical polishing and wafer bonding were optimized during the process of fabricating the sensor system and, in addition to detailing the sensor system simulation and characterization; the optimized processes are detailed in the dissertation. This absolute pressure sensor is designed to function optimally within the human blood pressure range of 50-350mmHg. The layout and modeling of the sensor uses finite element analysis (FEA) software. The simulations for membrane deflection, stress analysis and electro-mechanical analysis are performed for 100 μm2 and 400μm2sensors. The membrane deflection-pressure, capacitance-pressure and resonant frequency-pressure graphs were obtained, and detailed in the dissertation, along with the planar inductor simulation for

  12. APT: An Autonomous Tool for Measuring Acceleration, Pressure, and Temperature with Large Dynamic Range and Bandwidth

    NASA Astrophysics Data System (ADS)

    Heesemann, M.; Davis, E. E.

    2015-12-01

    We describe a new tool developed to facilitate the study of inter-related geodetic, geodynamic, seismic, and oceanographic phenomena. It incorporates a novel tri-axial accelerometer developed by Quartz Seismic Sensors, Inc, a pressure sensor developed by Paroscientific Inc., and a low-power, high-precision frequency counter and data logger built by RBR, Ltd. The sensors, counters, and loggers are housed in a 7 cm o.d., 70 cm long pressure case designed for use in up to 12 km of water. Sampling intervals are programmable from 0.1 s to 1 hr; standard memory can store up to 30 million samples; total power consumption is roughly 115 mW when operating continuously (1 s.p.s. or higher) and proportionately lower when operating intermittently (e.g., 2 mW at 1 sample per min.). Serial and USB communications protocols allow a variety of download and cable-connection options. Measurement precision of the order of 10-8 of full scale (e.g., 4000 m water depth, 1 g) allows observations of pressure and acceleration variations of 0.4 Pa and 0.1 μm s-2. Long-term variations in vertical acceleration are sensitive to displacement through the gravity gradient at a level of roughly 2 cm; long-term variations in horizontal acceleration are sensitive to tilt at a level of 0.01 μRad. With these sensitivities and the broad bandwidth (5 Hz to DC), ground motion associated with microseisms and seismic waves, tidal loading, and slow and rapid geodynamic deformation normally studied by disparate instruments can be observed with a single tool. The first c. 1-year deployment with the instrument connected to the Ocean Networks Canada NEPTUNE observatory cable is underway to study interseismic deformation of the Cascadia subduction zone. It will then be deployed at the Hikurangi subduction zone to study episodic slow slip. Deployment of the tool for the initial test was accomplished by pushing the tool vertically below the seafloor with the remotely operated vehicle Jason, with no profile

  13. Application of PSP to Surface Pressure Measurement in High Knudsen Number Flows

    NASA Astrophysics Data System (ADS)

    Mori, Hideo; Niimi, Tomohide; Hirako, Madoka; Oshima, Yusuke

    2005-05-01

    The pressure sensitive paint (PSP) technique has the capability to be applied to high Knudsen number flows, such as low density gas flows, micro-flows, and so on. In this study, to inspect the feasibility of PSP for measurement of pressure on a solid surface in the high Knudsen number flows, fundamental properties of three types of PSP [PdTFPP, PdOEP and PtTFPP bound by poly(TMSP)] are examined especially in the range of pressure below 130 Pa (about 1 Torr). The pressure sensitivity against nitrogen monoxide is also examined for the above PSPs, to develop a technique for the composite measurement of the flow field structure and the surface pressure, using NO-LIF and PSP, respectively. As an application of PSP to low density gas flows, we measure the pressure distribution on a jet-impinging solid surface using PdOEP/poly(TMSP) with very high pressure sensitivity.

  14. Marvin: MARtian Vehicular INvestigator A Proposal for a Long-Range Pressurized Rover

    NASA Astrophysics Data System (ADS)

    1999-01-01

    NASA is planning manned missions to Mars in the near future. In order to fully exploit the available time on the surface for exploration, a roving vehicle is necessary. A nine-member student design team from the Wichita State University Department of Aerospace Engineering developed the MARtian Vehicular INvestigator (MARVIN) a manned, pressurized, long distance rover. In order to meet the unique requirements for successful operation in the harsh Martian environment a four wheeled, rover was designed with a composite pressure vessel six meters long and 2.5 meters in diameter. The rover is powered by twin proton exchange membrane fuel cells which provide electricity to the drive motors and onboard systems. The MARVIN concept is expected to have a 1500 km range with a maximum speed of 25 km/hr and a 14-day endurance.

  15. MEMS fiber-optic Fabry-Perot pressure sensor for high temperature application

    NASA Astrophysics Data System (ADS)

    Fang, G. C.; Jia, P. G.; Cao, Q.; Xiong, J. J.

    2016-10-01

    We design and demonstrate a fiber-optic Fabry-Perot pressure sensor (FOFPPS) for high-temperature sensing by employing micro-electro-mechanical system (MEMS) technology. The FOFPPS is fabricated by anodically bonding the silicon wafer and the Pyrex glass together and fixing the facet of the optical fiber in parallel with the silicon surface by glass frit and organic adhesive. The silicon wafer can be reduced through dry etching technology to construct the sensitive diaphragm. The length of the cavity changes with the deformation of the diaphragm due to the loaded pressure, which leads to a wavelength shift of the interference spectrum. The pressure can be gauged by measuring the wavelength shift. The pressure experimental results show that the sensor has linear pressure sensitivities ranging from 0 kPa to 600 kPa at temperature range between 20°C to 300°C. The pressure sensitivity at 300°C is approximately 27.63 pm/kPa. The pressure sensitivities gradually decrease with increasing the temperature. The sensor also has a linear thermal drift when temperature changes from 20°C - 300°C.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  17. Isentropic expansion of copper plasma in Mbar pressure range at “Luch” laser facility

    SciTech Connect

    Bel'kov, S. A.; Derkach, V. N.; Garanin, S. G.; Mitrofanov, E. I.; Voronich, I. N.; Fortov, V. E.; Levashov, P. R.; Minakov, D. V.

    2014-01-21

    We present experimental results on thermodynamic properties of dense copper plasma in Mbar pressure range. The laser facility “Luch” with laser intensity 10{sup 14} W/cm{sup 2} is used to compress copper up to ∼8 Mbar by a strong shock wave; subsequent expansion of copper plasma into Al, Ti, Sn allows us to obtain release isentropes of copper by the impedance–matching method. A theoretical analysis and quantum simulations show that in our experiments strongly coupled quantum plasma is generated.

  18. Melting temperatures of MgO under high pressure determined by micro-texture observation

    NASA Astrophysics Data System (ADS)

    Kimura, T.; Ohfuji, H.; Nishi, M.; Irifune, T.

    2016-12-01

    Periclase (MgO) is the second abundant mineral after bridgmanite in the Earth's lower mantle, and its melting temperature (Tm) under pressure is important to constrain the chemical composition of ultra-deep magma formed near the mantle-core boundary. However, the melting behavior is highly controversial among previous studies: a laser-heated diamond anvil cell (LHDAC) study reported a melting curve with a dTm/dP of 30 K/GPa at zero pressure [1], while several theoretical computations gave substantially higher dTm/dP of 90 100 K/GPa [2,3]. We performed a series of LHDAC experiments for measurements of Tm of MgO under high pressure, using single crystal MgO as the starting material. The melting was detected by using micro-texture observations of the quenched samples. We found that the laser-heated area of the sample quenched from the Tm in previous LHDAC experiments [1] showed randomly aggregated granular crystals, which was not caused by melting, but by plastic deformation of the sample. This suggests that the Tms of their study were substantially underestimated. On the other hand, the sample recovered from the temperature higher by 1500-1700 K than the Tms in previous LHDAC experiments showed a characteristic internal texture comparable to the solidification texture typically shown in metal casting. We determined the Tms based on the observation of this texture up to 32 GPa. Fitting our Tms to the Simon equation yields dTm/dP of 82 K/GPa at zero pressure, which is consistent with those of the theoretical predictions (90 100 K/GPa) [2,3]. Extrapolation of the present melting curve of MgO to the pressure of the CMB (135 GPa) gives a melting temperature of 8900 K. The present steep melting slope offers the eutectic composition close to peridotite (in terms of Mg/Si ratio) throughout the lower mantle conditions. According to the model for sink/float relationship between the solid mantle and the magma [4], a considerable amount of iron (Fe/(Mg+Fe) > 0.24) is expected

  19. Polynomial approximations of thermodynamic properties of arbitrary gas mixtures over wide pressure and density ranges

    NASA Technical Reports Server (NTRS)

    Allison, D. O.

    1972-01-01

    Computer programs for flow fields around planetary entry vehicles require real-gas equilibrium thermodynamic properties in a simple form which can be evaluated quickly. To fill this need, polynomial approximations were found for thermodynamic properties of air and model planetary atmospheres. A coefficient-averaging technique was used for curve fitting in lieu of the usual least-squares method. The polynomials consist of terms up to the ninth degree in each of two variables (essentially pressure and density) including all cross terms. Four of these polynomials can be joined to cover, for example, a range of about 1000 to 11000 K and 0.00001 to 1 atmosphere (1 atm = 1.0133 x 100,000 N/m sq) for a given thermodynamic property. Relative errors of less than 1 percent are found over most of the applicable range.

  20. Thermodynamic and Transport Properties of Real Air Plasma in Wide Range of Temperature and Pressure

    NASA Astrophysics Data System (ADS)

    Wang, Chunlin; Wu, Yi; Chen, Zhexin; Yang, Fei; Feng, Ying; Rong, Mingzhe; Zhang, Hantian

    2016-07-01

    Air plasma has been widely applied in industrial manufacture. In this paper, both dry and humid air plasmas' thermodynamic and transport properties are calculated in temperature 300-100000 K and pressure 0.1-100 atm. To build a more precise model of real air plasma, over 70 species are considered for composition. Two different methods, the Gibbs free energy minimization method and the mass action law method, are used to determinate the composition of the air plasma in a different temperature range. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto has been applied using the most recent collision integrals. It is found that the presence of CO2 has almost no effect on the properties of air plasma. The influence of H2O can be ignored except in low pressure air plasma, in which the saturated vapor pressure is relatively high. The results will serve as credible inputs for computational simulation of air plasma. supported by the National Key Basic Research Program of China (973 Program)(No. 2015CB251002), National Natural Science Foundation of China (Nos. 51521065, 51577145), the Science and Technology Project Funds of the Grid State Corporation (SGTYHT/13-JS-177), the Fundamental Research Funds for the Central Universities, and State Grid Corporation Project (GY71-14-004)

  1. Kinetics of the NCN + NO reaction over a broad temperature and pressure range.

    PubMed

    Welz, Oliver; Olzmann, Matthias

    2012-07-12

    Rate coefficients for the reaction (3)NCN + NO → products (R3) were measured in the temperature range 251-487 K at pressures from 10 mbar up to 50 bar with helium as the bath gas. The experiments were carried out in slow-flow reactors by using pulsed excimer laser photolysis of NCN(3) at 193 or 248 nm for the production of NCN. Pseudo-first-order conditions ([NCN](0) ≪ NO) were applied, and NCN was detected time-resolved by resonant laser-induced fluorescence excited near 329 nm. The measurements at the highest pressures yielded values of k(3) ∼ 8 × 10(-12) cm(3) s(-1) virtually independent of temperature and pressure, which indicates a substantially smaller high-pressure limiting value of k(3) than predicted in earlier works. Our experiments at pressures below 1 bar confirm the negative temperature and positive pressure dependence of the rate coefficient k(3) found in previous investigations. The falloff behavior of k(3) was rationalized by a master equation analysis based on a barrierless association step (3)NCN + NO ↔ NCNNO((2)A″) followed by a fast internal conversion NCNNO((2)A″) ↔ NCNNO((2)A'). From 251-487 K and above 30 mbar, the rate coefficient k(3) is well represented by a Troe parametrization for a recombination/dissociation reaction, k(3)(T,P) = k(4)(∞)k(4)(0)[M]F(k(4)(0)[M] + k(4)(∞))(-1), where k(4) represents the rate coefficient for the recombination reaction (3)NCN + NO. The following parameters were determined (30% estimated error of the absolute value of k(3)): k(4)(0)[M=He] = 1.91 × 10(-30)(T/300 K)(-3.3) cm(6) s(-1)[He], k(4)(∞) = 1.12 × 10(-11) exp(-23 K/T) cm(3) s(-1), and F(C) = 0.28 exp(173 K/T).

  2. Pressure-tuning micro-Raman spectra of artists' pigments: α- and β-copper phthalocyanine polymorphs.

    PubMed

    Beaulieu-Houle, Guillaume; Gilson, Denis F R; Butler, Ian S

    2014-01-03

    The two polymorphs of copper phthalocyanine, α- and β-CuPc, have been examined by micro-Raman spectroscopy at pressures approaching 5.0 GPa. The metastable α-polymorph does not exhibit any structural changes, while the more thermodynamically stable β-polymorph does exhibit a reversible phase transition at 2.0 GPa. The pressure dependences (dν/dP) for a selected number of vibrational modes are reported. Two regions of the Raman spectra, 800-900 cm(-1) and 1100-1200 cm(-1), are sensitive to pressure such that they can be used as indicators of the polymorphic form.

  3. Foot posture, range of motion and plantar pressure characteristics in obese and non-obese individuals.

    PubMed

    Butterworth, Paul A; Urquhart, Donna M; Landorf, Karl B; Wluka, Anita E; Cicuttini, Flavia M; Menz, Hylton B

    2015-02-01

    Obesity is a world-wide health problem and is strongly associated with musculoskeletal disorders of the lower limb. The aim of this study was to evaluate plantar loading patterns in obese and non-obese individuals, while accounting for the contribution of foot structure, range of motion and walking speed. Sixty-eight participants (mean±SD age, 52.6±8.0 years), including 47 females (69%), underwent assessments of body mass index, foot pain and foot structure. Plantar pressures were also obtained, using a floor-mounted resistive sensor mat system. Multiple regression analysis was used to determine which variables were most strongly associated with plantar loading patterns. Obese individuals exhibited flatter feet, reduced inversion-eversion range of motion, and higher peak plantar pressures when walking. After accounting for foot structure and walking speed, bodyweight was found to be significantly associated with elevated loading of the foot, particularly the forefoot and midfoot. These findings suggest that obesity increases the stresses applied to the foot directly, via increased bodyweight, and indirectly, via alterations to foot structure, which may partly explain the link between obesity and the development of foot pain. Clinicians dealing with foot problems should consider the effect of increased bodyweight on plantar loading in obese patients.

  4. A 100 μm diameter capacitive pressure sensor with 50 MPa dynamic range

    NASA Astrophysics Data System (ADS)

    Luo, Xin; Gianchandani, Yogesh B.

    2016-04-01

    This paper presents fully sealed absolute capacitive pressure sensors for high-pressure applications in hydraulic environments. The sensors have a ø100 μm diaphragm and a nominal interelectrode gap of 3 μm. The interiors of the cavities are electrically isolated, allowing the sensors to operate at the high end of the pressure range with the center of the diaphragm in contact with the substrate beneath it. The sensors are monolithically fabricated using a combination of surface micromachining and through-wafer isolated bulk-silicon lead transfer for backside contacts. This structure allows the device footprints to be reduced to about 150  ×  150 μm2, and simplifies system integration. Fabricated sensors with diaphragm thicknesses of 3 μm (C100t3) and 5 μm (C100t5) are tested in an oil environment at pressures up to 20 MPa and 50 MPa, respectively. The average sensitivities are 7200 ppm MPa-1 (3.1 fF MPa-1) for C100t3, and 3400 ppm MPa-1 (1.6 fF MPa-1) for C100t5 in the non-contact mode. In the contact mode, the average sensitivities are 9900 ppm MPa-1 (5.3 fF MPa-1) for C100t3, and 3100 ppm MPa-1 (1.6 fF MPa-1) for C100t5. A multiphysics finite element analysis approach that accommodates contact mode simulations is also presented.

  5. A simple expression for pressure drops of water and other low molecular liquids in the flow through micro-orifices

    NASA Astrophysics Data System (ADS)

    Hasegawa, Tomiichi; Ushida, Akiomi; Narumi, Takatsune

    2015-12-01

    Flows are generally divided into two types: shear flows and shear-free elongational (extensional) flows. Both are necessary for a thorough understanding of the flow properties of a fluid. Shear flows are easy to achieve in practice, for example, through Poiseuille or Couette flows. Shear-free elongational flows are experimentally hard to achieve, resulting in an incomplete understanding of the flow properties of fluids in micro-devices. Nevertheless, flows through micro-orifices are useful for probing the properties of elongational flows at high elongational rates; although these flows exhibit shear and elongation, the elongation is dominant and the shear is negligible in the central region of the flows. We previously reported an anomalous reduction in pressure drops in the flows of water, a 50/50 mixture of glycerol and water, and silicone oils through micro-orifices. In the present paper, we rearrange the data presented in the previous paper and reveal a simple relationship where the pressure drop is proportional to the velocity through the micro-orifices, independent of the orifice diameter and the viscosity of the liquids tested. We explain our observations by introducing a "fluid element" model, in which fluid elements are formed on entering the orifice. The model is based on the idea that low molecular liquids, including water, generate strong elongational stress, similar to a polymer solution, in the flow through micro-orifices.

  6. Structure investigations of PP-PA blends

    NASA Astrophysics Data System (ADS)

    Janicki, Jaroslaw; Wlochowicz, Andrzej; Slusarczyk, Czeslaw

    1997-02-01

    In the paper we have used the SAXS method in order to determine the supermolecular structure parameters, including the transition layer thickness, of polypropylene/polyamide-6 (PP/PA) blends. The transition layer thickness has been obtained by means of two methods elaborated by Koberstein and co-workers and by Ruland, respectively. Both these methods assume that changes of the electron density in the transition region can be described by a Gaussian function with a standard deviation (sigma) . The parameter (sigma) have been determined graphically from the appropriate plots. Then, the thickness of the phase boundary E was estimated as (root)12(sigma) . The investigated PP/PA blends are multiphase systems and the problem of determination of the boundary width is more complicated because the meaning of Porod's law must be considered with caution. This problem is discussed based on wide range of the investigated samples prepared over various pressure and crystallization temperature conditions.

  7. Measuring Fluid Pressure on the Pore-scale

    NASA Astrophysics Data System (ADS)

    Giordano, N.; Petrovitch, C.; Pyrak-Nolte, L. J.

    2008-12-01

    The capillary pressure plays an important role in theoretical descriptions of immiscible two-phase flow in porous media. Most measurements of capillary pressure on the pore-scale are either based on external measurements of the fluid pressure of two immiscible fluids in a porous media or extracted from the analysis of interfacial curvature from digital-photomicroscopy. Experimentally, it is very difficult to measure local pressure at the interface of a two-phase flow system at the pore scale. In this study, we developed micro- capacitors for measuring local pressures in two-dimensional micro-models. Micro-models are transparent microfluidic flow cells that enable direct imaging of fluid distributions in known pore geometries. They are made using photo-projection lithography to make percolative structures that have areal dimensions of 600 µm x 600 µm with an aperture of 2.0 μ m. The size of the micro-model enables full-frame optical imaging during drainage and imbibition experiments. We have modified the micro-model fabrication process to include micro-capacitors to measure local pressure. We added two thin metal films to the opposing glass substrates prior to our normal micromodel assembly. The metal films act as a parallel plate capacitor. The capacitance depends on the dielectric material inside the plates which in our study is decane and nitrogen. As the pressure in the fluids changes, there is a corresponding change in the density of the fluid, and hence a change in the dielectric constant. The changes in dieletric constant are measured via precision measurements of the capacitance. Capacitance changes as small of 1/107 are measured which corresponds to pressure changes of 102 Pa. This pressure resolution is approximately 1% of the full range in our typical drainage/imbibition cycles. This capacitance method enables us to make measurements of small pressure changes with high spatial resolution. The spatial resolution is set by the size of the capacitor

  8. Analysis of Frequency Response and Scale-Factor of Tuning Fork Micro-Gyroscope Operating at Atmospheric Pressure

    PubMed Central

    Ding, Xukai; Li, Hongsheng; Ni, Yunfang; Sang, Pengcheng

    2015-01-01

    This paper presents a study of the frequency response and the scale-factor of a tuning fork micro-gyroscope operating at atmospheric pressure in the presence of an interference sense mode by utilizing the approximate transfer function. The optimal demodulation phase (ODP), which is always ignored in vacuum packaged micro-gyroscopes but quite important in gyroscopes operating at atmospheric pressure, is obtained through the transfer function of the sense mode, including the primary mode and the interference mode. The approximate transfer function of the micro-gyroscope is deduced in consideration of the interference mode and the ODP. Then, the equation describing the scale-factor of the gyroscope is also obtained. The impacts of the interference mode and Q-factor on the frequency response and the scale-factor of the gyroscope are analyzed through numerical simulations. The relationship between the scale-factor and the demodulation phase is also illustrated and gives an effective way to find out the ODP in practice. The simulation results predicted by the transfer functions are in close agreement with the results of the experiments. The analyses and simulations can provide constructive guidance on bandwidth and sensitivity designs of the micro-gyroscopes operating at atmospheric pressure. PMID:25621614

  9. Analysis of frequency response and scale-factor of tuning fork micro-gyroscope operating at atmospheric pressure.

    PubMed

    Ding, Xukai; Li, Hongsheng; Ni, Yunfang; Sang, Pengcheng

    2015-01-22

    This paper presents a study of the frequency response and the scale-factor of a tuning fork micro-gyroscope operating at atmospheric pressure in the presence of an interference sense mode by utilizing the approximate transfer function. The optimal demodulation phase (ODP), which is always ignored in vacuum packaged micro-gyroscopes but quite important in gyroscopes operating at atmospheric pressure, is obtained through the transfer function of the sense mode, including the primary mode and the interference mode. The approximate transfer function of the micro-gyroscope is deduced in consideration of the interference mode and the ODP. Then, the equation describing the scale-factor of the gyroscope is also obtained. The impacts of the interference mode and Q-factor on the frequency response and the scale-factor of the gyroscope are analyzed through numerical simulations. The relationship between the scale-factor and the demodulation phase is also illustrated and gives an effective way to find out the ODP in practice. The simulation results predicted by the transfer functions are in close agreement with the results of the experiments. The analyses and simulations can provide constructive guidance on bandwidth and sensitivity designs of the micro-gyroscopes operating at atmospheric pressure.

  10. Long-range AIS message analysis based on the TianTuo-3 micro satellite

    NASA Astrophysics Data System (ADS)

    Li, Shiyou; Chen, Lihu; Chen, Xiaoqian; Zhao, Yong; Bai, Yuzhu

    2017-07-01

    The "Type-27 AIS message" is the long-range AIS broadcast message, which is primarily intended for the long-range detection of AIS typically by satellite. The TT3-AIS uses a four-frequency receiver scheme which includes two frequency channels conventionally applied by the AIS system and two new frequency channels allocated to the long-range AIS broadcast message. To the end of April 2016, the TT3-AIS has already received more than 11,400 packets of Type-27 AIS messages. In this paper, a detailed analysis of the Type-27 AIS messages is performed. Firstly, an eavesdropper diagram of the space-borne AIS received from the worldwide vessels is obtained. Secondly, the analysis to the trend of the number and the ratio of the new-type vessels is performed based on the Type-27 AIS message. The detection probability of the new-type vessels is also discussed. The result would be helpful on the usage of the long-range AIS message both for data application and for the improvement in designing the next space-based AIS receiver.

  11. Catalyzed Combustion In Micro-Propulsion Devices: Project Status

    NASA Technical Reports Server (NTRS)

    Sung, C. J.; Schneider, S. J.

    2003-01-01

    the basic units, or in a rapid sequence in order to provide gradual but steady low-g acceleration. These arrays of micro-propulsion systems would offer unprecedented flexibility and redundancy for satellite propulsion and reaction control for launch vehicles. A high-pressure bi-propellant micro-rocket engine is already being developed using MEMS technology. High pressure turbopumps and valves are to be incorporated onto the rocket chip . High pressure combustion of methane and O2 in a micro-combustor has been demonstrated without catalysis, but ignition was established with a spark. This combustor has rectangular dimensions of 1.5 mm by 8 mm (hydraulic diameter 3.9 mm) and a length of 4.5 mm and was operated at 1250 kPa with plans to operate it at 12.7 MPa. These high operating pressures enable the combustion process in these devices, but these pressures are not practical for pressure fed satellite propulsion systems. Note that the use of these propellants requires an ignition system and that the use of a spark would impose a size limitation to this micro-propulsion device because the spark unit cannot be shrunk proportionately with the thruster. Results presented in this paper consist of an experimental evaluation of the minimum catalyst temperature for initiating/supporting combustion in sub-millimeter diameter tubes. The tubes are resistively heated and reactive premixed gases are passed through the tubes. Tube temperature and inlet pressure are monitored for an indication of exothermic reactions and composition changes in the gases.

  12. A proposed search for dark-matter axions in the 0.6-16 micro-eV range

    NASA Technical Reports Server (NTRS)

    Vanbibber, Karl; Sikivie, P.; Sullivan, N. S.; Tanner, D. B.; Turner, Michael S.; Moltz, D. M.

    1991-01-01

    A proposed experiment is described to search for dark matter axions in the mass range 0.6 to 16 micro-eV. The method is based on the Primakoff conversion of axions into monochromatic microwave photons inside a tunable microwave cavity in a large volume high field magnet, as described by Sikivie. This proposal capitalizes on the availability of two Axicell magnets from the decommissioned Mirror Fusion Test Facility (MFTF-B) fusion machine at LLNL. Assuming a local dark matter density in axions of rho = 0.3 GeV/cu cm, the axion would be found or ruled out at the 97 pct. c.l. in the above mass range in 48 months.

  13. Melting temperatures of MgO under high pressure by micro-texture analysis

    NASA Astrophysics Data System (ADS)

    Kimura, T.; Ohfuji, H.; Nishi, M.; Irifune, T.

    2017-06-01

    Periclase (MgO) is the second most abundant mineral after bridgmanite in the Earth's lower mantle, and its melting behaviour under pressure is important to constrain rheological properties and melting behaviours of the lower mantle materials. Significant discrepancies exist between the melting temperatures of MgO determined by laser-heated diamond anvil cell (LHDAC) and those based on dynamic compressions and theoretical predictions. Here we show the melting temperatures in earlier LHDAC experiments are underestimated due to misjudgment of melting, based on micro-texture observations of the quenched samples. The high melting temperatures of MgO suggest that the subducted cold slabs should have higher viscosities than previously thought, suggesting that the inter-connecting textural feature of MgO would not play important roles for the slab stagnation in the lower mantle. The present results also predict that the ultra-deep magmas produced in the lower mantle are peridotitic, which are stabilized near the core-mantle boundary.

  14. Melting temperatures of MgO under high pressure by micro-texture analysis

    PubMed Central

    Kimura, T.; Ohfuji, H.; Nishi, M.; Irifune, T.

    2017-01-01

    Periclase (MgO) is the second most abundant mineral after bridgmanite in the Earth's lower mantle, and its melting behaviour under pressure is important to constrain rheological properties and melting behaviours of the lower mantle materials. Significant discrepancies exist between the melting temperatures of MgO determined by laser-heated diamond anvil cell (LHDAC) and those based on dynamic compressions and theoretical predictions. Here we show the melting temperatures in earlier LHDAC experiments are underestimated due to misjudgment of melting, based on micro-texture observations of the quenched samples. The high melting temperatures of MgO suggest that the subducted cold slabs should have higher viscosities than previously thought, suggesting that the inter-connecting textural feature of MgO would not play important roles for the slab stagnation in the lower mantle. The present results also predict that the ultra-deep magmas produced in the lower mantle are peridotitic, which are stabilized near the core–mantle boundary. PMID:28580945

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

    PubMed

    Shinoda, Keiji; Noguchi, Naoki

    2008-01-01

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

  16. Acoustic model of micro-pressure wave emission from a high-speed train tunnel

    NASA Astrophysics Data System (ADS)

    Miyachi, T.

    2017-03-01

    The micro-pressure wave (MPW) radiated from a tunnel portal can, if audible, cause serious problems around tunnel portals in high-speed railways. This has created a need to develop an acoustic model that considers the topography around a radiation portal in order to predict MPWs more accurately and allow for higher speed railways in the future. An acoustic model of MPWs based on linear acoustic theory is developed in this study. First, the directivity of sound sources and the acoustical effect of topography are investigated using a train launcher facility around a portal on infinitely flat ground and with an infinite vertical baffle plate. The validity of linear acoustic theory is then discussed through a comparison of numerical results obtained using the finite difference method (FDM) and experimental results. Finally, an acoustic model is derived that considers sound sources up to the second order and Green's function to represent the directivity and effect of topography, respectively. The results predicted by this acoustic model are shown to be in good agreement with both numerical and experimental results.

  17. Design and characterization of an RF excited micro atmospheric pressure plasma jet for reference in plasma medicine

    NASA Astrophysics Data System (ADS)

    Schulz-von der Gathen, Volker

    2015-09-01

    Over the last decade a huge variety of atmospheric pressure plasma jets has been developed and applied for plasma medicine. The efficiency of these non-equilibrium plasmas for biological application is based on the generated amounts of reactive species and radiation. The gas temperatures stay within a range tolerable for temperature-sensitive tissues. The variety of different discharge geometries complicates a direct comparison. In addition, in plasma-medicine the combination of plasma with reactive components, ambient air, as well as biologic tissue - typically also incorporating fluids - results in a complex system. Thus, real progress in plasma-medicine requires a profound knowledge of species, their fluxes and processes hitting biological tissues. That will allow in particular the necessary tailoring of the discharge to fit the conditions. The complexity of the problem can only be overcome by a common effort of many groups and requires a comparison of their results. A reference device based on the already well-investigated micro-scaled atmospheric pressure plasma jet is presented. It is developed in the frame of the European COST initiative MP1101 to establish a publicly available, stable and reproducible source, where required plasma conditions can be investigated. Here we present the design and the ideas behind. The presentation discusses the requirements for the reference source and operation conditions. Biological references are also defined by the initiative. A specific part of the talk will be attributed to the reproducibility of results from various samples of the device. Funding by the DFG within the Package Project PAK816 ``Plasma Cell Interaction in Dermatology'' and the Research Unit FOR 1123 ``Physics of microplasmas'' is gratefully acknowledged.

  18. Characterization of the Distal Esophagus High-Pressure Zone with Manometry, Ultrasound and Micro-Computed Tomography

    PubMed Central

    Vegesna, Anil K.; Sloan, Joshua A.; Singh, Baltej; Phillips, Steven J; Braverman, Alan S.; Barbe, Mary F.; Ruggieri, Michael R.; Miller, Larry S.

    2012-01-01

    Background We sought to determine how the individual components of the distal esophagus and proximal stomach form the gastroesophageal junction high-pressure zone (GEJHPZ) anti-reflux barrier. Methods An endoscopic ultrasound/manometry catheter was pulled through the proximal stomach and distal esophagus in 20 normal subjects. The axial length and width of individual structures on endoscopic ultrasound were measured. The anatomic orientation of gastroesophageal junction (GEJ) components was examined in two organ donor specimens using micro-computed tomography (micro-CT). Key Results The three distinct structures identified within the GEJHPZ, from distal to proximal, were: the gastric clasp and sling muscle fiber complex, crural diaphragm, and lower esophageal circular smooth muscle fibers (LEC). The LEC was statistically significantly thicker than adjacent esophageal muscles. These structures were associated with 3 pressure peaks. The pressure peak produced by the clasp/sling fiber complex often overlapped with the pressure peak from the crural diaphragm. The most proximal peak, associated with the LEC, was significantly greater and bimodal in 9 of 20 subjects. This bimodal LEC pressure peak correlated with two areas of thickened muscle observed with ultrasound. Micro-CT of GEJ from organ donors confirmed the two areas of thickened muscle. Conclusions and inferences Three distinct anatomic structures, the clasp and sling muscle fibers, crural diaphragm, and LEC combine to form the anti-reflux barrier of the proximal stomach and distal esophagus. The clasp and sling muscle fibers combine with the crural diaphragm to form a distal pressure profile. The more proximal LEC has a bimodal pressure profile in some patients. PMID:22998376

  19. Knee arthritis pain is reduced and range of motion is increased following moderate pressure massage therapy.

    PubMed

    Field, Tiffany; Diego, Miguel; Gonzalez, Gladys; Funk, C G

    2015-11-01

    The literature on massage therapy effects on knee pain suggests that pain was reduced based on self-report, but little is known about range of motion (ROM) effects. Medical School staff and faculty who had knee arthritis pain were randomly assigned to a moderate pressure massage therapy or a waitlist control group (24 per group). Self-reports included the WOMAC (pain, stiffness and function) and the Pittsburgh Sleep Quality Index. ROM and ROM-related pain were assessed before and after the last sessions. The massage group showed an immediate post-massage increase in ROM and a decrease in ROM-associated pain. On the last versus the first day of the study, the massage group showed greater increases in ROM and decreases in ROM-related pain as well as less self-reported pain and sleep disturbances than the waitlist control group. These data highlight the effectiveness of moderate pressure massage therapy for increasing ROM and lessening ROM-related pain and long-term pain and sleep disturbances. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Ultrananocrystalline Diamond Cantilever Wide Dynamic Range Acceleration/Vibration /Pressure Sensor

    DOEpatents

    Krauss, Alan R.; Gruen, Dieter M.; Pellin, Michael J.; Auciello, Orlando

    2003-09-02

    An ultrananocrystalline diamond (UNCD) element formed in a cantilever configuration is used in a highly sensitive, ultra-small sensor for measuring acceleration, shock, vibration and static pressure over a wide dynamic range. The cantilever UNCD element may be used in combination with a single anode, with measurements made either optically or by capacitance. In another embodiment, the cantilever UNCD element is disposed between two anodes, with DC voltages applied to the two anodes. With a small AC modulated voltage applied to the UNCD cantilever element and because of the symmetry of the applied voltage and the anode-cathode gap distance in the Fowler-Nordheim equation, any change in the anode voltage ratio V1/V2 required to maintain a specified current ratio precisely matches any displacement of the UNCD cantilever element from equilibrium. By measuring changes in the anode voltage ratio required to maintain a specified current ratio, the deflection of the UNCD cantilever can be precisely determined. By appropriately modulating the voltages applied between the UNCD cantilever and the two anodes, or limit electrodes, precise independent measurements of pressure, uniaxial acceleration, vibration and shock can be made. This invention also contemplates a method for fabricating the cantilever UNCD structure for the sensor.

  1. Ultrananocrystalline diamond cantilever wide dynamic range acceleration/vibration/pressure sensor

    DOEpatents

    Krauss, Alan R.; Gruen, Dieter M.; Pellin, Michael J.; Auciello, Orlando

    2002-07-23

    An ultrananocrystalline diamond (UNCD) element formed in a cantilever configuration is used in a highly sensitive, ultra-small sensor for measuring acceleration, shock, vibration and static pressure over a wide dynamic range. The cantilever UNCD element may be used in combination with a single anode, with measurements made either optically or by capacitance. In another embodiment, the cantilever UNCD element is disposed between two anodes, with DC voltages applied to the two anodes. With a small AC modulated voltage applied to the UNCD cantilever element and because of the symmetry of the applied voltage and the anode-cathode gap distance in the Fowler-Nordheim equation, any change in the anode voltage ratio V1/N2 required to maintain a specified current ratio precisely matches any displacement of the UNCD cantilever element from equilibrium. By measuring changes in the anode voltage ratio required to maintain a specified current ratio, the deflection of the UNCD cantilever can be precisely determined. By appropriately modulating the voltages applied between the UNCD cantilever and the two anodes, or limit electrodes, precise independent measurements of pressure, uniaxial acceleration, vibration and shock can be made. This invention also contemplates a method for fabricating the cantilever UNCD structure for the sensor.

  2. A bossed diaphragm piezoresistive pressure sensor with a peninsula-island structure for the ultra-low-pressure range with high sensitivity

    NASA Astrophysics Data System (ADS)

    Zhao, Libo; Xu, Tingzhong; Hebibul, Rahman; Jiang, Zhuangde; Ding, Jianjun; Peng, Niancai; Guo, Xin; Xu, Yu; Wang, Hongyan; Zhao, Yulong

    2016-12-01

    A sensor chip with a bossed diaphragm combined with a peninsula-island structure was developed for a piezoresistive pressure sensor. By introducing a stiffness mutation above the gap position between the peninsula and island structures, the strain energy of the proposed diaphragm was mainly concentrated upon the gap position, which remarkably increased the sensitivity of the sensor chip. A beam-diaphragm coupled model and an optimization method for the novel sensor chip were also developed, which gave guidelines for optimizing the sensor chip structure. Finally, a sensor chip with the bossed diaphragm combined with peninsula-island structure was fabricated and tested. The experimental results showed that the proposed sensor chip was able to measure ultra-low pressure within 500 Pa with high sensitivity.

  3. Methane storage in nanoporous material at supercritical temperature over a wide range of pressures

    PubMed Central

    Wu, Keliu; Chen, Zhangxin; Li, Xiangfang; Dong, Xiaohu

    2016-01-01

    The methane storage behavior in nanoporous material is significantly different from that of a bulk phase, and has a fundamental role in methane extraction from shale and its storage for vehicular applications. Here we show that the behavior and mechanisms of the methane storage are mainly dominated by the ratio of the interaction between methane molecules and nanopores walls to the methane intermolecular interaction, and a geometric constraint. By linking the macroscopic properties of the methane storage to the microscopic properties of a system of methane molecules-nanopores walls, we develop an equation of state for methane at supercritical temperature over a wide range of pressures. Molecular dynamic simulation data demonstrates that this equation is able to relate very well the methane storage behavior with each of the key physical parameters, including a pore size and shape and wall chemistry and roughness. Moreover, this equation only requires one fitted parameter, and is simple, reliable and powerful in application. PMID:27628747

  4. Raman spectroscopic characterization of CH4 density over a wide range of temperature and pressure

    USGS Publications Warehouse

    Shang, Linbo; Chou, I-Ming; Burruss, Robert; Hu, Ruizhong; Bi, Xianwu

    2014-01-01

    The positions of the CH4 Raman ν1 symmetric stretching bands were measured in a wide range of temperature (from −180 °C to 350 °C) and density (up to 0.45 g/cm3) using high-pressure optical cell and fused silica capillary capsule. The results show that the Raman band shift is a function of both methane density and temperature; the band shifts to lower wavenumbers as the density increases and the temperature decreases. An equation representing the observed relationship among the CH4 ν1 band position, temperature, and density can be used to calculate the density in natural or synthetic CH4-bearing inclusions.

  5. Methane storage in nanoporous material at supercritical temperature over a wide range of pressures

    NASA Astrophysics Data System (ADS)

    Wu, Keliu; Chen, Zhangxin; Li, Xiangfang; Dong, Xiaohu

    2016-09-01

    The methane storage behavior in nanoporous material is significantly different from that of a bulk phase, and has a fundamental role in methane extraction from shale and its storage for vehicular applications. Here we show that the behavior and mechanisms of the methane storage are mainly dominated by the ratio of the interaction between methane molecules and nanopores walls to the methane intermolecular interaction, and a geometric constraint. By linking the macroscopic properties of the methane storage to the microscopic properties of a system of methane molecules-nanopores walls, we develop an equation of state for methane at supercritical temperature over a wide range of pressures. Molecular dynamic simulation data demonstrates that this equation is able to relate very well the methane storage behavior with each of the key physical parameters, including a pore size and shape and wall chemistry and roughness. Moreover, this equation only requires one fitted parameter, and is simple, reliable and powerful in application.

  6. Positron range in tissue-equivalent materials: experimental microPET studies.

    PubMed

    Alva-Sánchez, H; Quintana-Bautista, C; Martínez-Dávalos, A; Ávila-Rodríguez, M A; Rodríguez-Villafuerte, M

    2016-09-07

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with (18)F, (13)N or (68)Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  7. Positron range in tissue-equivalent materials: experimental microPET studies

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  8. Design, Fabrication and Prototype testing of a Chip Integrated Micro PEM Fuel Cell Accumulator combined On-Board Range Extender

    NASA Astrophysics Data System (ADS)

    Balakrishnan, A.; Mueller, C.; Reinecke, H.

    2014-11-01

    In this work we present the design, fabrication and prototype testing of Chip Integrated Micro PEM Fuel Cell Accumulator (CIμ-PFCA) combined On-Board Range Extender (O-BRE). CIμ-PFCA is silicon based micro-PEM fuel cell system with an integrated hydrogen storage feature (palladium metal hydride), the run time of CIμ-PFCA is dependent on the stored hydrogen, and in order to extend its run time an O-BRE is realized (catalytic hydrolysis of chemical hydride, NaBH4. Combining the CIμ-PFCA and O-BRE on a system level have few important design requirements to be considered; hydrogen regulation, gas -liquid separator between the CIμ-PFCA and the O-RE. The usage of traditional techniques to regulate hydrogen (tubes), gas-liquid phase membranes (porous membrane separators) are less desirable in the micro domain, due to its space constraint. Our approach is to use a passive hydrogen regulation and gas-liquid phase separation concept; to use palladium membrane. Palladium regulates hydrogen by concentration diffusion, and its property to selectively adsorb only hydrogen is used as a passive gas-liquid phase separator. Proof of concept is shown by realizing a prototype system. The system is an assembly of CIμ-PFCA, palladium membrane and the O-BRE. The CIμ-PFCA consist of 2 individually processed silicon chips, copper supported palladium membrane realized by electroplating followed by high temperature annealing process under inter atmosphere and the O-BRE is realized out of a polymer substrate by micromilling process with platinum coated structures, which functions as a catalyst for the hydrolysis of NaBH4. The functionality of the assembled prototype system is demonstrated by the measuring a unit cell (area 1 mm2) when driven by the catalytic hydrolysis of chemical hydride (NaBH4 and the prototype system shows run time more than 15 hours.

  9. Feasibility investigations on a novel micro-manufacturing process for fabrication of fuel cell bipolar plates: Internal pressure-assisted embossing of micro-channels with in-die mechanical bonding

    NASA Astrophysics Data System (ADS)

    Koç, Muammer; Mahabunphachai, Sasawat

    In this paper, we present the results of our studies on conceptual design and feasibility experiments towards development of a novel hybrid manufacturing process to fabricate fuel cell bipolar plates that consists of multi-array micro-channels on a large surface area. The premises of this hybrid micro-manufacturing process stem from the use of an internal pressure-assisted embossing process (cold or warm) combined with mechanical bonding of double bipolar plates in a single-die and single-step operation. Such combined use of hydraulic and mechanical forming forces and in-process bonding will (a) enable integrated forming of micro-channels on both surfaces (as anode and cathode flow fields) and at the middle (as cooling channels), (b) reduce the process steps, (c) reduce variation in dimensional tolerances and surface finish, (d) increase the product quality, (e) increase the performance of fuel cell by optimizing flow-field designs and ensuring consistent contact resistance, and (f) reduce the overall stack cost. This paper explains two experimental investigations that were performed to characterize and evaluate the feasibility of the conceptualized manufacturing process. The first investigation involved hydroforming of micro-channels using thin sheet metals of SS304 with a thickness of 51 μm. The width of the channels ranged from 0.46 to 1.33 mm and the height range was between 0.15 and 0.98 mm. Our feasibility experiments resulted in that different aspect ratios of micro-channels could be fabricated using internal pressure in a controllable manner although there is a limit to very sharp channel shapes (i.e., high aspect ratios with narrow channels). The second investigation was on the feasibility of mechanical bonding of thin sheet metal blanks. The effects of different process and material variables on the bond quality were studied. Successful bonding of various metal blanks (Ni201, Al3003, and SS304) was obtained. The experimental results from both

  10. Changes in the biomechanical properties of a single cell induced by nonthermal atmospheric pressure micro-dielectric barrier discharge plasma.

    PubMed

    Choi, Hyeongwon; Choi, Eun Ha; Kim, Kyung Sook

    2017-10-01

    Mechanical properties of a single cell are closely related to the fate and functions of the cell. Changes in mechanical properties may cause diseases or cell apoptosis. Selective cytotoxic effects of nonthermal atmospheric pressure micro-dielectric barrier discharge (DBD) plasma have been demonstrated on cancer cells. In this work, changes in the mechanical properties of a single cell induced by nonthermal atmospheric pressure micro-DBD plasma were investigated using atomic force microscopy (AFM). Two cervical cancer cell lines (HeLa and SiHa) and normal human fibroblast cells (HFBs) were exposed to micro-DBD plasma for various exposure times. The elasticity of a single cell was determined by force-distance curve measurement using AFM. Young's modulus was decreased by plasma treatment for all cells. The Young's modulus of plasma-treated HeLa cells was decreased by 75% compared to nontreated HeLa cells. In SiHa cells and HFBs, elasticity was decreased slightly. Chemical changes induced by the plasma treatment, which were observed by Raman spectroscopy, were also significant in HeLa cells compared to SiHa cells and HFBs. These results suggested that the molecular changes induced by micro-DBD plasma were related to cell mechanical changes. © 2017 Wiley Periodicals, Inc.

  11. Low-pressure micro-strip gas chamber and a search for a high-efficiency secondary-electron emitter

    SciTech Connect

    Anderson, D.F.; Kwan, S.; Sbarra, C.

    1994-11-01

    The test beam performance of a low-pressure micro-strip gas chamber with a thick CsI secondary-electron emitting surface as the source of primary ionization is presented. A study of the secondary-electron yield of CsI and KCl coated surfaces are discussed, as well as a promising new technique, CsI-treated CVD diamond films.

  12. Valveless pumping mechanics of the embryonic heart during cardiac looping: Pressure and flow through micro-PIV.

    PubMed

    Bark, D L; Johnson, B; Garrity, D; Dasi, L P

    2017-01-04

    Cardiovascular development is influenced by the flow-induced stress environment originating from cardiac biomechanics. To characterize the stress environment, it is necessary to quantify flow and pressure. Here, we quantify the flow field in a developing zebrafish heart during the looping stage through micro-particle imaging velocimetry and by analyzing spatiotemporal plots. We further build upon previous methods to noninvasively quantify the pressure field at a low Reynolds number using flow field data for the first time, while also comparing the impact of viscosity models. Through this method, we show that the atrium builds up pressure to ~0.25mmHg relative to the ventricle during atrial systole and that atrial expansion creates a pressure difference of ~0.15mmHg across the atrium, resulting in efficient cardiac pumping. With these techniques, it is possible to noninvasively fully characterize hemodynamics during heart development.

  13. The Association Between Blood Pressure and Normal Range Thyroid Function Tests in a Population Based Tehran Thyroid Study.

    PubMed

    Amouzegar, A; Heidari, M; Gharibzadeh, S; Mehran, L; Tohidi, M; Azizi, F

    2016-03-01

    Several studies have shown an association between overt hypothyroidism and diastolic hypertension. Association between subclinical hypothyroidism and hypertension is a matter of debate. The aim of this study was to examine the association of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure with serum thyroid hormones levels in euthyroid subjects.Data from 4 756 individuals of the Tehran Thyroid study (TTS) without any previously known thyroid disease were analyzed. We divided participants based on TSH tertiles. Serum TSH and free T4 (FT4) concentration, systolic blood pressure (SBP), diastolic blood pressure (BPD) body mass index (BMI) were measured in all subjects.Among 5 786 individuals participated, 4 985 were euthyroid. After implementing exclusion criteria, 4 756 individuals remained of whom 2 122 (44.6%) were male and 2 634 (55.4%) were female. Multiple linear regression analysis revealed no association between TSH levels within reference ranges and blood pressure profile. No significant relationship was observed between TSH levels and systolic or diastolic blood pressure or the mean arterial pressure or pulse pressure in each tertile of TSH. There was a negative association between pulse pressure and TSH in the second tertile (r=- 0.066, p=0.009). Regression analysis showed that FT4 was significantly associated with systolic blood pressure, diastolic blood pressure, pulse pressure and mean arterial pressure.No association was found between serum TSH and blood pressure profile in euthyroid subjects. Serum FT4 levels showed a positive association with blood pressure profiles. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Circadian rhythms in blood pressure in free-ranging three-toed sloths (Bradypus variegatus).

    PubMed

    Duarte, D P F; Silva, V L; Jaguaribe, A M; Gilmore, D P; Da Costa, C P

    2003-02-01

    Blood pressure (BP) profiles were monitored in nine free-ranging sloths (Bradypus variegatus) by coupling one common carotid artery to a BP telemetry transmitter. Animals moved freely in an isolated and temperature-controlled room (24 degrees C) with 12/12-h artificial light-dark cycles and behaviors were observed during resting, eating and moving. Systolic (SBP) and diastolic (DBP) blood pressures were sampled for 1 min every 15 min for 24 h. BP rhythm over 24 h was analyzed by the cosinor method and the mesor, amplitude, acrophase and percent rhythm were calculated. A total of 764 measurements were made in the light cycle and 721 in the dark cycle. Twenty-four-hour values (mean +/- SD) were obtained for SBP (121 +/- 22 mmHg), DBP (86 +/- 17 mmHg), mean BP (MBP, 98 +/- 18 mmHg) and heart rate (73 +/- 16 bpm). The SBP, DBP and MBP were significantly higher (unpaired Student t-test) during the light period (125 +/- 21, 88 +/- 15 and 100 +/- 17 mmHg, respectively) than during the dark period (120 +/- 21, 85 +/- 17 and 97 +/- 17 mmHg, respectively) and the acrophase occurred between 16:00 and 17:45 h. This circadian variation is similar to that observed in cats, dogs and marmosets. The BP decreased during "behavioral sleep" (MBP down from 110 +/- 19 to 90 +/- 19 mmHg at 21:00 to 8:00 h). Both feeding and moving induced an increase in MBP (96 +/- 17 to 119 +/- 17 mmHg at 17:00 h and 97 +/- 19 to 105 +/- 12 mmHg at 15:00 h, respectively). The results show that conscious sloths present biphasic circadian fluctuations in BP levels, which are higher during the light period and are mainly synchronized with feeding.

  15. COMPARISON OF VIDEO-GUIDED, LIVE INSTRUCTED, AND SELF-GUIDED FOAM ROLL INTERVENTIONS ON KNEE JOINT RANGE OF MOTION AND PRESSURE PAIN THRESHOLD: A RANDOMIZED CONTROLLED TRIAL.

    PubMed

    Cheatham, Scott W; Kolber, Morey J; Cain, Matt

    2017-04-01

    The use of foam rollers to provide tissue massage is a commonly used intervention by rehabilitation professionals for their patients and clients. Currently, there is no consensus on the optimal foam rolling treatment approach. Of particular interest are the effects of different instructional methods of foam rolling, as individuals ultimately perform these interventions independently outside of formal care. Finding the optimal instructional method may help improve the individual's understanding of the technique, allowing for a safe and effective intervention. The purpose of this study was to compare the effects of video-guided, live instructed, and self-guided foam roll interventions on knee flexion Range of Motion (ROM) and pressure pain thresholds. Forty-five healthy adults were recruited and randomly allocated to one of three intervention groups: video-guided, live-instructed, and self-guided. Each foam roll intervention lasted a total of 2 minutes. Dependent variables included knee flexion ROM and pressure pain threshold of the left quadriceps. Statistical analysis included subject demographic calculations and appropriate parametric and non-parametric tests to measure changes within and between intervention groups. Each intervention group showed significant gains in knee flexion ROM (p ≤ 0.003) and pressure pain thresholds (p < 0.001). An approximate 5 degree increase of knee flexion and a 150 kPa increase in pressure pain threshold was observed at the posttest measure for all groups. There was no significant difference (p=0.25) found between intervention groups. All three foam roll interventions showed short-term increases in knee flexion ROM and pressure pain thresholds. The two instructional methods (video and live instruction) and the self-guided method produced similar outcomes and can be used interchangeably. Individuals can benefit from various types of instruction and in cases of limited resources video may offer an alternative or adjunct to

  16. Respiratory response of the deep-sea amphipod Stephonyx biscayensis indicates bathymetric range limitation by temperature and hydrostatic pressure.

    PubMed

    Brown, Alastair; Thatje, Sven

    2011-01-01

    Depth zonation of fauna on continental margins is well documented. Whilst increasing hydrostatic pressure with depth has long been considered a factor contributing significantly to this pattern, discussion of the relative significance of decreasing temperature with depth has continued. This study investigates the physiological tolerances of fed and starved specimens of the bathyal lysianassoid amphipod Stephonyx biscayensis at varying temperature to acute pressure exposure by measuring the rate of oxygen consumption. Acclimation to atmospheric pressure is shown to have no significant interaction with temperature and/or pressure effects. Similarly, starvation is shown to have no significant effect on the interaction of temperature and pressure. Subsequently, the effect of pressure on respiration rate is revealed to be dependent on temperature: pressure equivalent to 2000 m depth was tolerated at 1 and 3°C; pressure equivalent to 2500 m depth was tolerated at 5.5°C; at 10°C pressure equivalent to 3000 m depth was tolerated. The variation in tolerance is consistent with the natural distribution range reported for this species. There are clear implications for hypotheses relating to the observed phenomenon of a biodiversity bottleneck between 2000 and 3000 metres, and for the potential for bathymetric range shifts in response to global climate change.

  17. Cost and Performance Report - Validation of the Low-Range Differential Pressure (LRDP) Leak Detection System

    NASA Astrophysics Data System (ADS)

    2002-03-01

    The Naval Facilities Engineering Service Center (NFESC) Port Hueneme, California, and its industrial partners, Vista Research, Inc., and Vista Engineering Technologies, L.L.C., have demonstrated and validated (DEM/VAL) an innovative mass-based leak detection system for bulk fuel underground storage tanks (USTs). The Low-Range Differential Pressure (LRDP) system is a computer-controlled system that can reliably detect small leaks in bulk USTs ranging in size from 50,000 gal to 12,500,000 gal. As part of this project, it has been evaluated for performance by an independent third party in a l22.5-ft diameter, 2,100,000-gal tank following EPA's standard test procedures. The LRDP meets monthly monitoring and annual precision (tightness) test regulatory compliance requirements using either a 10-h (overnight) or 24-h test. The LRDP has several significant cost advantages over the internal and external technologies. The cost advantages are realized because of the extremely high performance of the LRDP and the probability of false alarm, the on-line monitoring capability of the LRDP when pennanently installed in a tank, the capability of the system to conduct a short test (an overnight test), and the low recurring costs associated with testing. The cost of a tracer method is expensive because of the high recurring cost of testing. The cost of other mass-based methods is high because of lower performance and the inability to meet both the monthly monitoring and annual precision regulatory requirements with an online system. In addition, the LRDP has the potential to save DOD many hundreds of millions of dollars in terms of clean-up and tank replacement cost avoidance.

  18. Relationship between a range of sedentary behaviours and blood pressure during early adolescence.

    PubMed

    Gopinath, B; Baur, L A; Hardy, L L; Kifley, A; Rose, K A; Wong, T Y; Mitchell, P

    2012-06-01

    Very few studies have explored links between physical activity, sedentary behaviours and blood pressure (BP) in early adolescence. We aimed to assess the association between a range of sedentary activities (screen time, television (TV) viewing, computer usage, video game usage and time spent in homework or reading) and BP in schoolchildren. Eligible year-7 students (2353/3144, mean age 12.7 years) from a random cluster sample of 21 Sydney schools were examined during 2003-2005. Parents and children completed detailed questionnaires of activity. BP was measured using a standard protocol and high BP was defined using published guidelines. Height and weight were measured, and body mass index (BMI) calculated. After adjusting for age, sex, ethnicity, parental education, height, BMI and time spent in physical activity, each hour per day spent in screen time, watching TV and playing video games was associated with a significant increase in diastolic BP of 0.44 (P=0.0001), 0.99 (P<0.0001) and 0.64 mm Hg (P=0.04), respectively. In contrast, each hour per day spent reading was associated with a decrease of 0.91 (P=0.01) and 0.69 mm Hg (P=0.02) in systolic and diastolic BP, respectively. Our results indicate that addressing different types of sedentary activities could be a potentially important strategy to reduce the prevalence of elevated BP in children.

  19. The nature of functional variability in plantar pressure during a range of controlled walking speeds

    PubMed Central

    Pataky, Todd C.; Crompton, Robin H.; Savage, Russell; Bates, Karl T.

    2016-01-01

    During walking, variability in step parameters allows the body to adapt to changes in substrate or unexpected perturbations that may occur as the feet interface with the environment. Despite a rich literature describing biomechanical variability in step parameters, there are as yet no studies that consider variability at the body–environment interface. Here, we used pedobarographic statistical parametric mapping (pSPM) and two standard measures of variability, mean square error (m.s.e.) and the coefficient of variation (CV), to assess the magnitude and spatial variability in plantar pressure across a range of controlled walking speeds. Results by reduced major axis, and pSPM regression, revealed no consistent linear relationship between m.s.e. and speed or m.s.e. and Froude number. A positive linear relationship, however, was found between CV and walking speed and CV and Froude number. The spatial distribution of variability was highly disparate when assessed by m.s.e. and CV: relatively high variability was consistently confined to the medial and lateral forefoot when measured by m.s.e., while the forefoot and heel show high variability when measured by CV. In absolute terms, variability by CV was universally low (less than 2.5%). From these results, we determined that variability as assessed by m.s.e. is independent of speed, but dependent on speed when assessed by CV. PMID:27853618

  20. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor... section, the containment system must have a: (a) Tank pressure gauge at the point where cargo flow is...

  1. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor... section, the containment system must have a: (a) Tank pressure gauge at the point where cargo flow is...

  2. Source depth dependence of micro-tsunamis recorded with ocean-bottom pressure gauges: The January 28, 2000 Mw 6.8 earthquake off Nemuro Peninsula, Japan

    USGS Publications Warehouse

    Hirata, K.; Takahashi, H.; Geist, E.; Satake, K.; Tanioka, Y.; Sugioka, H.; Mikada, H.

    2003-01-01

    Micro-tsunami waves with a maximum amplitude of 4-6 mm were detected with the ocean-bottom pressure gauges on a cabled deep seafloor observatory south of Hokkaido, Japan, following the January 28, 2000 earthquake (Mw 6.8) in the southern Kuril subduction zone. We model the observed micro-tsunami and estimate the focal depth and other source parameters such as fault length and amount of slip using grid searching with the least-squares method. The source depth and stress drop for the January 2000 earthquake are estimated to be 50 km and 7 MPa, respectively, with possible ranges of 45-55 km and 4-13 MPa. Focal depth of typical inter-plate earthquakes in this region ranges from 10 to 20 km and stress drop of inter-plate earthquakes generally is around 3 MPa. The source depth and stress drop estimates suggest that the earthquake was an intra-slab event in the subducting Pacific plate, rather than an inter-plate event. In addition, for a prescribed fault width of 30 km, the fault length is estimated to be 15 km, with possible ranges of 10-20 km, which is the same as the previously determined aftershock distribution. The corresponding estimate for seismic moment is 2.7x1019 Nm with possible ranges of 2.3x1019-3.2x1019Nm. Standard tide gauges along the nearby coast did not record any tsunami signal. High-precision ocean-bottom pressure measurements offshore thus make it possible to determine fault parameters of moderate-sized earthquakes in subduction zones using open-ocean tsunami waveforms. Published by Elsevier Science B. V.

  3. Pyrolysis product distribution of a Victorian brown coal under high pressures

    SciTech Connect

    Sathe, C.; Li, C.Z.

    1999-07-01

    A Loy Yang brown coal sample was pyrolyzed in a wire-mesh reactor at pressures ranging from 100 kPa to 1000 kPa. Tar yield was found to be very sensitive to changes in heating rate, peak temperature, holding time and pressure. Tar yield decreased with increases in pressure at high heating rate. At low heating rate tar yield was not sensitive to changes in pressure. Char yields were found to be much less sensitive to changes in pressure and/or heating rate. UV absorption spectroscopy of the tar samples indicated that the yields of larger aromatic ring systems decreased with increasing pressure and/or decreasing heating rate. The effects of pressure are mainly due to the changes in the transportation of volatile precursors with pressure. Increases in pressure might have slowed down the bulk diffusion within meso- and macro-pores in char, which in turn have slowed down the Knudsen diffusion in the micro-pores due to the reduced concentration gradients for the Knudsen diffusion. During the extended stay within the char particle, volatile precursors were thermally cracked, leading to the retention of some larger aromatic ring systems as char and the release of other components as tar and gas.

  4. Pressure distribution on a vectored-thrust V/STOL fighter in the transition-speed range. [wind tunnel tests to measure pressure distribution on body and wing

    NASA Technical Reports Server (NTRS)

    Mineck, R. E.; Margason, R. J.

    1974-01-01

    A wind-tunnel investigation has been conducted in the Langley V/STOL tunnel with a vectored-thrust V/STOL fighter configuration to obtain detailed pressure measurements on the body and on the wing in the transition-speed range. The vectored-thrust jet exhaust induced a region of negative pressure coefficients on the lower surface of the wing and on the bottom of the fuselage. The location of the jet exhaust relative to the wing was a major factor in determining the extent of the region of negative pressure coefficients.

  5. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    ERIC Educational Resources Information Center

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  6. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    ERIC Educational Resources Information Center

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  7. High pressure single-crystal micro X-ray diffraction analysis with GSE_ADA/RSV software

    NASA Astrophysics Data System (ADS)

    Dera, Przemyslaw; Zhuravlev, Kirill; Prakapenka, Vitali; Rivers, Mark L.; Finkelstein, Gregory J.; Grubor-Urosevic, Ognjen; Tschauner, Oliver; Clark, Simon M.; Downs, Robert T.

    2013-08-01

    GSE_ADA/RSV is a free software package for custom analysis of single-crystal micro X-ray diffraction (SCμXRD) data, developed with particular emphasis on data from samples enclosed in diamond anvil cells and subject to high pressure conditions. The package has been in extensive use at the high pressure beamlines of Advanced Photon Source (APS), Argonne National Laboratory and Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. The software is optimized for processing of wide-rotation images and includes a variety of peak intensity corrections and peak filtering features, which are custom-designed to make processing of high pressure SCμXRD easier and more reliable.

  8. CePt2In7: Shubnikov-de Haas measurements on micro-structured samples under high pressures

    NASA Astrophysics Data System (ADS)

    Kanter, J.; Moll, P.; Friedemann, S.; Alireza, P.; Sutherland, M.; Goh, S.; Ronning, F.; Bauer, E. D.; Batlogg, B.

    2014-03-01

    CePt2In7 belongs to the CemMnIn3 m + 2 n heavy fermion family, but compared to the Ce MIn5 members of this group, exhibits a more two dimensional electronic structure. At zero pressure the ground state is antiferromagnetically ordered. Under pressure the antiferromagnetic order is suppressed and a superconducting phase is induced, with a maximum Tc above a quantum critical point around 31 kbar. To investigate the changes in the Fermi Surface and effective electron masses around the quantum critical point, Shubnikov-de Haas measurements were conducted under high pressures in an anvil cell. The samples were micro-structured and contacted using a Focused Ion Beam (FIB). The Focused Ion Beam enables sample contacting and structuring down to a sub-micrometer scale, making the measurement of several samples with complex shapes and multiple contacts on a single anvil feasible.

  9. Thermochemical micro imprinting of single-crystal diamond surface using a nickel mold under high-pressure conditions

    NASA Astrophysics Data System (ADS)

    Imoto, Yuji; Yan, Jiwang

    2017-05-01

    Single-crystal diamond is an important material for cutting tools, micro electro mechanical systems, optical devices, and semiconductor substrates. However, the techniques for producing microstructures on diamond surface with high efficiency and accuracy have not been established. This paper proposes a thermochemical imprinting method for transferring microstructures from a nickel (Ni) mold onto single-crystal diamond surface. The Ni mold was micro-structured by a nanoindenter and then pressed against the diamond surface under high temperature and pressure in argon atmosphere. Results show that microstructures on the Ni mold were successfully transferred onto the diamond surface, and their depth increased with both pressure and temperature. Laser micro-Raman spectroscopy, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses indicate that a graphite layer was formed over the contact area between diamond and Ni during pressing, and after washing by a mixed acid, the graphite layer could be completely removed. This study demonstrated the feasibility of a cost-efficient fabrication method for large-area microstructures on single-crystal diamond.

  10. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-05-01

    Because of the high travel speed, the complex flow dynamics around an aircraft and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realized with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 hPa to 800 hPa, and a water vapour concentration range of more than three orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements show an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2% and 5.1% during in flight operation on the HALO airplane

  11. The Design and Optimization of a Highly Sensitive and Overload-Resistant Piezoresistive Pressure Sensor.

    PubMed

    Meng, Xiawei; Zhao, Yulong

    2016-03-09

    A piezoresistive pressure sensor with a beam-membrane-dual-island structure is developed for micro-pressure monitoring in the field of aviation, which requires great sensitivity and overload resistance capacity. The design, fabrication, and test of the sensor are presented in this paper. By analyzing the stress distribution of sensitive elements using the finite element method, a novel structure incorporating sensitive beams with a traditional bossed diaphragm is built up. The proposed structure proved to be advantageous in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the sensor equations. Fabricated on an n-type single crystal silicon wafer, the sensor chips are wire-bonded to a printed circuit board (PCB) and packaged for experiments. The static and dynamic characteristics are tested and discussed. Experimental results show that the sensor has a sensitivity as high as 17.339 μV/V/Pa in the range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure. Due to the excellent performance, the sensor can be applied in measuring micro-pressure lower than 500 Pa.

  12. OMVPE growth of GaInAsSb in the 2 to 2.4 {micro}m range

    SciTech Connect

    Charache, G.W.; Wang, C.A.

    1997-12-01

    Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} epilayers were grown lattice matched to GaSb substrates by organometallic vapor phase epitaxy using all organometallic precursors, which include triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony. Layers were grown over a temperature range between 525 and 575 C, a V/III ratio range between 0.9 and 1.7, x < 0.2 and y < 0.2, and on (100) GaSb substrates with 2{degree} toward (100) or 6{degree} toward (111)B. The overall material quality of these alloys depends on growth temperature, In content, V/III ratio, and substrate misorientation. A mirror-like surface morphology and room temperature photoluminescence (PL) could be obtained for GaInAsSb layers with peak emission in the wavelength range between 2 and 2.4 {micro}m. Based on epilayer surface morphology and low temperature PL spectra, the crystal quality improves for growth temperature decreasing from 575 to 525 C, and with decreasing In content. In general, GaInAsSb layers grown on (100) GaSb substrates with a 6{degree} toward (111)B misorientation exhibited smoother surfaces and narrower full width at half-maximum values of 4 K PL spectra than layers grown on the more standard substrate 9100 2{degree} toward (110). Nominally undoped GaInAsSb layers grown at 550 C are p-type with 300 K hole concentration of {approximately} 5 {times} 10{sup 15} cm{sup {minus}3} and hole mobility of {approximately} 430 to 560 cm{sup 2}/V-s. The n- and p-type doping of GaInAsSb with diethyltellurium and dimethylzinc, respectively, are also reported.

  13. Pressure effect on the long-range order in CeB6

    NASA Astrophysics Data System (ADS)

    Sera, M.; Ikeda, S.; Iwakubo, H.; Uwatoko, Y.; Hane, S.; Kosaka, M.; Kunii, S.

    2006-08-01

    The pressure effect of CeB6 was investigated. The pressure dependence of the Néel temperature, TN and the critical field from the antiferro-magnetic phase III to antiferro-quadrupolar phase II, HcIII-II of CeB6 exhibits the unusual pressure dependence that the suppression rate of HcIII-II is much larger than that of TN. In order to explain this unusual result, we have performed the mean field calculation for the 4-sublattice model assuming that the pressure dependence of TN, the antiferro-octupolar and quadrupolar temperatures, Toct and TQ as follows; dTN/dP<0, dToct/dP>dTQ/dP>0 and could explain the unusual pressure dependence of TN and HcIII-II.

  14. Final report on the key comparison, CCM.M.P-K15.1 in the pressure range from 1.0 × 10-4 Pa to 1.0 Pa

    NASA Astrophysics Data System (ADS)

    Wuethrich, Christian; Hongyan, Yu

    2017-01-01

    At the CCM WG-LP meeting in Berlin in April 2011 the National Institute of Metrology of the people's republic of China asked for an opportunity to be linked to the CCM.M.P-K15 comparison which just ended. METAS, which had been active as pilot for the CCM.M.P-K15, agreed to make a link with NIM. The NIM introduced a new static expansion system in his laboratory. Two spinning rotor gauges and a control electronic are used as transfer standard. The circulation of the transfer standard was made in spring 2012. The drift of the accommodation coefficient of the two SRG was measured by the pilot before and after the comparison. The stability of the transfer standards was excellent and the equivalence between METAS and NIM has been demonstrated. A link to the CCM.M.P­K15 has been established using the results from METAS. It has been possible to achieve a link with a small uncertainty due to the strong correlation of the measurements of METAS in the two comparisons. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  15. High quality x-ray absorption spectroscopy measurements with long energy range at high pressure using diamond anvil cell

    SciTech Connect

    Hong, X.; Newville, M.; Prakapenka, V.B.; Rivers, M.L.; Sutton, S.R.

    2009-07-31

    We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective method to obtain accurate XAFS spectrum free from DAC induced glitches has been lacking. It was found that these glitches, whose energy positions are very sensitive to the relative orientation between DAC and incident x-ray beam, can be effectively eliminated using an iterative algorithm based on repeated measurements over a small angular range of DAC orientation, e.g., within {+-}3{sup o} relative to the x-ray beam direction. Demonstration XAFS spectra are reported for rutile-type GeO{sub 2} recorded by traditional ambient pressure and high pressure DAC methods, showing similar quality at 440 eV above the absorption edge. Accurate XAFS spectra of GeO{sub 2} glass were obtained at high pressure up to 53 GPa, providing important insight into the structural polymorphism of GeO{sub 2} glass at high pressure. This method is expected be applicable for in situ XAFS measurements using a diamond anvil cell up to ultrahigh pressures.

  16. High quality x-ray absorption spectroscopy measurements with long energy range at high pressure using diamond anvil cell

    PubMed Central

    Hong, Xinguo; Newville, Matthew; Prakapenka, Vitali B.; Rivers, Mark L.; Sutton, Stephen R.

    2009-01-01

    We describe an approach for acquiring high quality x-ray absorption fine structure (XAFS) spectroscopy spectra with wide energy range at high pressure using diamond anvil cell (DAC). Overcoming the serious interference of diamond Bragg peaks is essential for combining XAFS and DAC techniques in high pressure research, yet an effective method to obtain accurate XAFS spectrum free from DAC induced glitches has been lacking. It was found that these glitches, whose energy positions are very sensitive to the relative orientation between DAC and incident x-ray beam, can be effectively eliminated using an iterative algorithm based on repeated measurements over a small angular range of DAC orientation, e.g., within ±3° relative to the x-ray beam direction. Demonstration XAFS spectra are reported for rutile-type GeO2 recorded by traditional ambient pressure and high pressure DAC methods, showing similar quality at 440 eV above the absorption edge. Accurate XAFS spectra of GeO2 glass were obtained at high pressure up to 53 GPa, providing important insight into the structural polymorphism of GeO2 glass at high pressure. This method is expected be applicable for in situ XAFS measurements using a diamond anvil cell up to ultrahigh pressures. PMID:19655966

  17. A micro-machined piezoelectric flexural-mode hydrophone with air backing: a hydrostatic pressure-balancing mechanism for integrity preservation.

    PubMed

    Choi, Sungjoon; Lee, Haksue; Moon, Wonkyu

    2010-09-01

    Although an air-backed thin plate is an effective sound receiver structure, it is easily damaged via pressure unbalance caused by external hydrostatic pressure. To overcome this difficulty, a simple pressure-balancing module is proposed. Despite its small size and relative simplicity, with proper design and operation, micro-channel structure provides a solution to the pressure-balancing problem. If the channel size is sufficiently small, the gas-liquid interface may move back and forth without breach by the hydrostatic pressure since the surface tension can retain the interface surface continuously. One input port of the device is opened to an intermediate liquid, while the other port is connected to the air-backing chamber. As the hydrostatic pressure increases, the liquid in the micro-channel compresses the air, and the pressure in the backing chamber is then equalized to match the external hydrostatic pressure. To validate the performance of the proposed mechanism, a micro-channel prototype is designed and integrated with the piezoelectric micro-machined flexural sensor developed in our previous work. The working principle of the mechanism is experimentally verified. In addition, the effect of hydrostatic pressure on receiving sensitivity is evaluated and compared with predicted behavior.

  18. A flexible and highly pressure-sensitive graphene-polyurethane sponge based on fractured microstructure design.

    PubMed

    Yao, Hong-Bin; Ge, Jin; Wang, Chang-Feng; Wang, Xu; Hu, Wei; Zheng, Zhi-Jun; Ni, Yong; Yu, Shu-Hong

    2013-12-10

    A fractured microstructure design: A new type of piezoresistive sensor with ultra-high-pressure sensitivity (0.26 kPa(-1) ) in low pressure range (<2 kPa) and minimum detectable pressure of 9 Pa has been fabricated using a fractured microstructure design in a graphene-nanosheet-wrapped polyurethane (PU) sponge. This low-cost and easily scalable graphene-wrapped PU sponge pressure sensor has potential application in high-spatial-resolution, artificial skin without complex nanostructure design.

  19. Micro-joule pico-second range Yb3+-doped fibre laser for medical applications in acupuncture

    NASA Astrophysics Data System (ADS)

    Alvarez-Chavez, J. A.; Rivera-Manrique, S. I.; Jacques, S. L.

    2011-08-01

    The work described here is based on the optical design, simulation and on-going implementation of a pulsed (Q-switch) Yb3+-doped, 1-um diffraction-limited fibre laser with pico-second, 10 micro-Joule-range energy pulses for producing the right energy pulses which could be of benefit for patients who suffer chronic headache, photophobia, and even nausea which could is sometimes triggered by a series of factors. The specific therapeutic effect known as acupunctural analgesia is the main objective of this medium-term project. It is a simple design on which commercially available software was employed for laser cavity design. Monte Carlo technique for skin light-transport, thermal diffusion and the possible thermal de-naturalization optical study and prediction will also be included in the presentation. Full optical characterization will be included and a complete set of recent results on the laser-skin interaction and the so called moxi-bustion from the laser design will be extensively described.

  20. Green micro-resistojet research at Delft University of Technology: new options for Cubesat propulsion

    NASA Astrophysics Data System (ADS)

    Cervone, A.; Zandbergen, B.; Guerrieri, D. C.; De Athayde Costa e Silva, M.; Krusharev, I.; van Zeijl, H.

    2017-03-01

    The aerospace industry is recently expressing a growing interest in green, safe and non-toxic propellants for the propulsion systems of the new generation of space vehicles, which is especially true in the case of Cubesat micro-propulsion systems. Demanding requirements are associated to the future missions and challenges offered by this class of spacecraft, where the availability of a propulsion system might open new possibilities for a wide range of applications including orbital maintenance and transfer, formation flying and attitude control. To accomplish these requirements, Delft University of Technology is currently developing two different concepts of water-propelled micro-thrusters based on MEMS technologies: a free molecular micro-resistojet operating with sublimating solid water (ice) at low plenum gas pressure of less than 600 Pa, and a more conventional micro-resistojet operating with liquid water heated and vaporized by means of a custom designed silicon heating chamber. In this status review paper, the current design and future expected developments of the two micro-propulsion concepts is presented and discussed, together with an initial analysis of the expected performance and potential operational issues. Results of numerical simulations conducted to optimize the design of the heating and expansion slots, as well as a detailed description of the manufacturing steps for the conventional micro-resistojet concept, are presented. Some intended steps for future research activities, including options for thrust intensity and direction control, are briefly introduced.

  1. Gas and heat dynamics of a micro-scaled atmospheric pressure plasma reference jet

    NASA Astrophysics Data System (ADS)

    Kelly, Seán; Golda, Judith; Turner, Miles M.; Schulz-von der Gathen, Volker

    2015-11-01

    Gas and heat dynamics of the ‘Cooperation on Science and Technology (COST) Reference Microplasma Jet’ (COST-jet), a European lead reference device for low temperature atmospheric pressure plasma application, are investigated. Of particular interest to many biomedical application scenarios, the temperature characteristics of a surface impacted by the jet are revealed. Schlieren imaging, thermocouple measurements, infrared thermal imaging and numerical modelling are employed. Temperature spatial profiles in the gas domain reveal heating primarily of the helium fraction of the gas mixture. Thermocouple and model temporal data show a bounded exponential temperature growth described by a single characteristic time parameter to reach  ∼63% or (1-1/e) fraction of the temperature increase. Peak temperatures occurred in the gas domain where the carrier jet exits the COST-jet, with values ranging from ambient temperatures to in excess of 100 °C in ‘α-mode’ operation. In a horizontal orientation of the COST-jet a curved trajectory of the helium effluent at low gas flows results from buoyant forces. Gas mixture profiles reveal significant containment of the helium concentrations for a surface placed in close proximity to the COST-jet. Surface heating of a quartz plate follows a similar bounded exponential temporal temperature growth as device heating. Spatial profiles of surface heating are found to correlate strongly to the impacting effluent where peak temperatures occur in regions of maximum surface helium concentration.

  2. Strength, Deformability and X-ray Micro-CT Observations of Deeply Buried Marble Under Different Confining Pressures

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Ju, Yang; Gao, Feng; Gui, Yi-Lin

    2016-11-01

    In this research, a series of triaxial compression experiments and X-ray observations were conducted to explore the strength, deformability and internal damage mechanism of deeply buried marble. The results show that an increase in confining pressure results in obvious brittle-ductile transition characteristics of deeply buried marble. The Young's modulus of the marble increased nonlinearly with increasing confining pressure. The peak and residual strength of the marble exhibit a clear linear relationship with the confining pressure, which can be described by the linear Mohr-Coulomb criterion. The sensitivity of the residual strength on the confining pressure was clearly higher than that of the peak strength. After uniaxial and triaxial compression failure, marble specimens were analyzed using a three-dimensional X-ray micro-CT scanning system. Based on horizontal and vertical cross-sections, the marble specimen is mainly dominated by axial splitting tensile cracks under uniaxial compression, but under confining pressure, the marble specimen is mainly dominated by a single shear crack. To quantitatively evaluate the internal damage of the marble material, the crack area and aperture extent for each horizontal cross-section were calculated by analyzing the binarized pictures. The system of crack planes under uniaxial compression is more complicated than that under triaxial compression, which is also supported by the evolution of the crack area and aperture extent. Finally, the brittle-ductile transition mechanism of the marble is discussed and interpreted according to the proposed conceptual models.

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

    PubMed

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

    2009-04-01

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

  4. Calculation of the density of solutions (sunflower oil + n-hexane) over a wide range of temperatures and pressure

    NASA Astrophysics Data System (ADS)

    Safarov, M. M.; Abdukhamidova, Z.

    1995-09-01

    We present the results from an experimental investigation of the density of the sunflower oil system as a function of the mass concentration of n-hexane in the ranges of temperatures T=290 520 K and pressures P=0.101 98.1 MPa. A method of hydrostatic weighing was used to measure the density of the solutions under study.

  5. Control of TTIP Solution for Atmospheric Pressure Plasma Jet and Deposition of TiO2 Micro-particles

    NASA Astrophysics Data System (ADS)

    Hayakawa, Masahiro; Parajulee, Shankar; Ikezawa, Shunjiro

    TiO2 deposition-methods are versatile and are expected to be more simple and easy, however, in recent years the industrial photocatalytic products have been developed enormously. In this work, photocatalytic TiO2 micro-particles are deposited using the atmospheric pressure plasma jet device. Here, deposition-method is carried out in two steps, at first, the hydrolysis reaction time has been able to control which will resolve the TTIP coagulating trouble during the transportation, by acidifying the solution with AA (Acetic acid) and DEA (Diethanolamine). An experiment was performed to measure the hydrolysis reaction time of TTIP (Titanium tetraisopropoxide) solution by He-Ne laser. Secondly, the deposition of TiO2 micro-particles was carried out using the atmospheric pressure plasma jet with the controlled TTIP solution in reaction time. Based on SEM and water contact angle measurement, it is found that the smaller the mixing ratios of TTIP and DEA the smaller the TiO2 particle size. Also, the smaller the TiO2 particles the smaller the contact angle under the UV irradiation which suffices the photocatalytic behavior.

  6. Resonance broadening of argon lines in a micro-scaled atmospheric pressure plasma jet (argon μAPPJ)

    NASA Astrophysics Data System (ADS)

    Pipa, A. V.; Ionikh, Yu. Z.; Chekishev, V. M.; Dünnbier, M.; Reuter, S.

    2015-06-01

    Optical emission from atmospheric pressure micro-jet operating with pure argon (argon μAPPJ) flow has been detected with a moderate resolution spectrometer. Large broadening of the several argon (Ar) lines has been observed in the near infrared spectral region. This effect was attributed to resonance broadening of the s2 (Paschen notation) level in 3p54s configuration. In the present work, corresponding line profiles are suggested for plasma diagnostics. For this, a general case of resonance broadening coefficient of noble gases is discussed. As broadening reflects the Ar density, and the static gas pressure of the jet is in equilibrium with the ambient, the local gas temperature can be inferred. An estimation of gas temperature from the width of the 750 nm Ar line is in agreement with rotational temperature of OH radicals determined from the A2Σ+ → X2Π (0, 0) band. At low temperatures (300-600 K) and at partial Ar pressure near atmospheric, the resonance width of the suggested lines is very sensitive to small temperature variations. High temperature sensitivity and large width make the resonance broadened lines very attractive for diagnostics of low temperature discharges at elevated pressure, e.g., as they are used in plasma-medicine.

  7. Outstanding micro-endemism in New Caledonia: More than one out of ten animal species have a very restricted distribution range.

    PubMed

    Caesar, Maram; Grandcolas, Philippe; Pellens, Roseli

    2017-01-01

    New Caledonia is a biodiversity hotspot, with an extremely high number of endemic species with narrow distribution ranges that are at high risk of extinction due to open-cast nickel mining, invasive species and seasonal man-induced fires. Mentions of micro-endemism permeate the literature on the biota of this archipelago. However, so far there has been no research comparing distribution range in different animal groups. The aim of this study is to examine the implication of different sampling effort variables in order to distinguish micro-endemicity from data deficiency, and evaluate the distribution range, frequency, and extent to which micro-endemism is common to several groups of organisms. We compiled a dataset derived from publications in Zoologia Neocaledonica, comprising 1,149 species, of which 86% are endemic to New Caledonia. We found that the sampling effort variables that were best correlated with distribution range were the number of sampling dates and the number of collectors per species. The median value of sampling dates was used to establish a cut-off point for defining adequately sampled species. We showed that, although only 52% of species were sampled adequately enough to determine their distribution range, the number of species with a very narrow distribution range was still high. Among endemics from New Caledonia, 12% (116 species) have ranges ≤5.2km2 and 3.9% (38 species) have ranges between 23 and 100 km2. Surprisingly, a similar trend was observed in non-endemic species: 22% occurred in areas ≤ 5.2 km2, and 8% in areas 23-100 km2, suggesting that environmental dissimilarity may play an important role in the distribution of these species. Micro-endemic species were predominant in 18 out of 20 orders. These results will contribute to a re-assessment of the IUCN red list of species in this archipelago, indicating that at least 116 species are probably critically endangered.

  8. A piezoelectric micro control valve with integrated capacitive sensing for ambulant blood pressure waveform monitoring

    NASA Astrophysics Data System (ADS)

    Groen, Maarten S.; Wu, Kai; Brookhuis, Robert A.; van Houwelingen, Marc J.; Brouwer, Dannis M.; Lötters, Joost C.; Wiegerink, Remco J.

    2014-12-01

    We have designed and characterized a MEMS microvalve with built-in capacitive displacement sensing and fitted it with a miniature piezoelectric actuator to achieve active valve control. The integrated displacement sensor enables high bandwidth proportional control of the gas flow through the valve. This is an essential requirement for non-invasive blood pressure waveform monitoring based on following the arterial pressure with a counter pressure. Using the capacitive sensor, we demonstrate negligible hysteresis in the valve control characteristics. Fabrication of the valve requires only two mask steps for deep reactive ion etching (DRIE) and one release etch.

  9. Comparison of a Vibrating Foam Roller and a Non-vibrating Foam Roller Intervention on Knee Range of Motion and Pressure Pain Threshold: A Randomized Controlled Trial.

    PubMed

    Cheatham, Scott W; Stull, Kyle R; Kolber, Morey J

    2017-08-08

    The use of foam rollers to provide soft-tissue massage has become a common intervention among health and fitness professionals. Recently, manufacturers have merged the science of vibration therapy and foam rolling with the development of vibrating foam rollers. To date, no peer reviewed investigations have been published on this technology. The purpose of this study was to compare the effects of a vibrating roller and non-vibrating roller intervention on prone knee flexion passive range of motion (ROM) and pressure pain thresholds (PPT) of the quadriceps musculature. Forty-five recreationally active adults were randomly allocated to one of three groups: vibrating roller, non-vibrating roller, and control. Each roll intervention lasted a total of 2 minutes. The control group did not roll. Dependent variables included prone knee flexion ROM and PPT measures. Statistical analysis included parametric and non-parametric tests to measure changes among groups. The vibrating roller demonstrated the greatest increase in PPT (180kPa, p< 0.001), followed by the non-vibrating roller (112kPa, p< 0.001), and control (61kPa, p<0.001). For knee ROM, the vibrating roller demonstrated the greatest increase in ROM (7 degrees, p< 0.001), followed by the non-vibrating roller (5 degrees, p< 0.001), and control (2 degrees, p<0.001). Between groups, there was significant difference in PPT between the vibrating and non-vibrating roller (p=.03) and vibrating roller and control (p<.001). There was also a significant difference between the non-vibrating roller and control (p<.001). For knee ROM, there was no significant difference between the vibrating and non-vibrating roller (p=.31). A significant difference was found between the vibrating roller and control group (p<.001) and non-vibrating roller and control (p<.001). The results suggest that a vibrating roller may increase an individual's tolerance to pain greater than a non-vibrating roller. This investigation should be considered

  10. Oxidation of gas-phase protactinium ions, Pa+ and Pa2+: formation and properties of PaO2(2+)(g), protactinyl.

    PubMed

    Santos, Marta; de Matos, António Pires; Marçalo, Joaquim; Gibson, John K; Haire, Richard G; Tyagi, Rajni; Pitzer, Russell M

    2006-05-04

    Oxidation reactions of bare and ligated, monopositive, and dipositive Pa ions in the gas phase were studied by Fourier transform ion cyclotron resonance mass spectrometry. Seven oxidants were employed, ranging from the thermodynamically robust N(2)O to the relatively weak CH(2)O-all oxidized Pa(+) to PaO(+) and PaO(+) to PaO(2)(+). On the basis of experimental observations, it was established that D[Pa(+)-O] and D[OPa(+)-O] > or = 751 kJ mol(-1). Estimates for D[Pa(+)-O], D[OPa(+)-O], IE[PaO], and IE[PaO(2)] were also obtained. The seven oxidants reacted with Pa(2+) to produce PaO(2+), indicating that D[Pa(2+)-O] > or = 751 kJ mol(-1). A particularly notable finding was the oxidation of PaO(2+) by N(2)O to PaO(2)(2+), a species, which formally comprises Pa(VI). Collision-induced dissociation of PaO(2)(2+) suggested the protactinyl connectivity, {O-Pa-O}(2+). The experimentally determined IE[PaO(2)(+)] approximately 16.6 eV is in agreement with self-consistent-field and configuration interaction calculations for PaO(2)(+) and PaO(2)(2+). These calculations provide insights into the electronic structures of these ions and indicate the participation of 5f orbitals in bonding and a partial "6p hole" in the case of protactinyl. It was found that PaO(2)(2+) catalyzes the oxidation of CO by N(2)O-such O atom transport via a dipositive metal oxide ion is distinctive. It was also observed that PaO(2)(2+) is capable of activating H(2) to form the stable PaO(2)H(2+) ion.

  11. Habitat, dispersal and propagule pressure control exotic plant infilling within an invaded range

    Treesearch

    Robert J. Warren; T. Ursell; A.D. Keiser; M.A. Bradford

    2013-01-01

    Deep in the heart of a longstanding invasion, an exotic grass is still invading. Range infilling potentially has the greatest impact on native communities and ecosystem processes, but receives much less attention than range expansion. ‘Snapshot’ studies of invasive plant dispersal, habitat and propagule limitations cannot determine whether a landscape is saturated or...

  12. Phase diagram of the selenium-sulfur system in the pressure range 1 × 10-5-1 × 10-1 MPa

    NASA Astrophysics Data System (ADS)

    Volodin, V. N.; Burabaeva, N. M.; Trebukhov, S. A.; Ersaiynova, A. A.

    2016-11-01

    The partial pressures of the components in the saturated vapor of the Se-S system were determined and presented as the temperature-concentration dependences. Based on these data, the boundaries of the melt-vapor phase transition at atmospheric pressure and in vacuum (1350, 100, and 10 Pa) were calculated. A complete phase diagram was constructed, which included the vapor-liquid equilibrium fields at atmospheric and low pressures, whose boundaries allowed us to determine the behavior of sulfur and selenium during distillation separation.

  13. Do current methods for endotracheal tube cuff inflation create pressures above the recommended range? A review of the evidence.

    PubMed

    Grant, Thomas

    2013-12-01

    Inflation and measurement of endotracheal (ET) tube cuff pressure is often not seen as a critical aspect of care in surgical patients. The morbidity associated by an overinflated cuff has been regularly highlighted in literature, for example mucosal ulceration (Combes et al 2001) and vocal cord paralysis (Holley & Gildea 1971). This article will outline techniques for the methods of inflation based on the latest scientific evidence. The author will seek to examine if intraoperative cuff assessment and monitoring should become routine for the anaesthetic practitioner and if current practice for inflating cuffs creates pressures outside the safe range.

  14. Reduced state relationship for limiting electrical conductances of aqueous ions over wide ranges of temperature and pressure

    NASA Astrophysics Data System (ADS)

    Marshall, William L.

    1987-09-01

    A reduced state relationship for limiting electrical conductances of aqueous ions to high temperatures and pressures is presented in which ionic conductance is a simple function of solvent density. Walden's rule is not observed. Specific parameters for 13 ions are included that can be used to calculate ionic conductances by the relationship. From these values, limiting equivalent conductances of many single and mixed aqueous electrolyte systems may be obtained over temperature-pressure ranges of 0-800 °C and up to 400 MPa (4000 bar), with reasonable estimates to 1000 °C and 1000 MPa.

  15. Influence of cavity loss on an extrinsic Fabry-Perot cavity intensity-based pressure sensor.

    PubMed

    Lű, Tao

    2015-09-01

    We present an extrinsic Fabry-Perot cavity intensity-based pressure sensor that mainly comprises a single-mode fiber end and an elastic monocrystalline silicon layer bonded to a silicon diaphragm. We investigated the influence of cavity loss on the performance indexes (PIS) of the intensity-based extrinsic Fabry-Perot cavity optical fiber pressure sensor. A buffer unit made of three incompressible oil cavities attenuated outside pressure and transformed pressure information into cavity length microchange information. Experimental results indicated that, under center quadrature-points within the linear regions of adjacent fringes, for an applied 40 kPa external pressure, cavity length was modulated by pressures of 69.9 kPa-109.9 kPa, 150.1 kPa-190 kPa, 220.1 kPa-259.9 kPa, and 279.9 kPa-319.9 kPa, output intensity ranges increased as 1 μW, 1.02 μW, 1.03 μW, and 1.05 μW, sensitivity increased as 0.01909 μW/kPa, 0.01986 μW/kPa, 0.02127 μW/kPa, and 0.02387 μW/kPa, but linearity degraded, as indicated by the standard deviation of linear fits of 0.02607, 0.02664, 0.02935, and 0.04879 due to cavity loss. Furthermore, the pressure ranges within the same quarter period decreased as 40 kPa, 37.45 kPa, 32.4 kPa, and 30.15 kPa. Consequently, the same lengths of linear regions within adjacent fringes of an approximately sinusoidal curve corresponded to different measurement ranges, linearities, and sensitivities. Initial cavity length must be chosen to optimize both signal strength and the PIS studied here in manufacturing this type sensor.

  16. Influence of cavity loss on an extrinsic Fabry-Perot cavity intensity-based pressure sensor

    NASA Astrophysics Data System (ADS)

    Lż, Tao

    2015-09-01

    We present an extrinsic Fabry-Perot cavity intensity-based pressure sensor that mainly comprises a single-mode fiber end and an elastic monocrystalline silicon layer bonded to a silicon diaphragm. We investigated the influence of cavity loss on the performance indexes (PIS) of the intensity-based extrinsic Fabry-Perot cavity optical fiber pressure sensor. A buffer unit made of three incompressible oil cavities attenuated outside pressure and transformed pressure information into cavity length microchange information. Experimental results indicated that, under center quadrature-points within the linear regions of adjacent fringes, for an applied 40 kPa external pressure, cavity length was modulated by pressures of 69.9 kPa-109.9 kPa, 150.1 kPa-190 kPa, 220.1 kPa-259.9 kPa, and 279.9 kPa-319.9 kPa, output intensity ranges increased as 1 μW, 1.02 μW, 1.03 μW, and 1.05 μW, sensitivity increased as 0.01909 μW/kPa, 0.01986 μW/kPa, 0.02127 μW/kPa, and 0.02387 μW/kPa, but linearity degraded, as indicated by the standard deviation of linear fits of 0.02607, 0.02664, 0.02935, and 0.04879 due to cavity loss. Furthermore, the pressure ranges within the same quarter period decreased as 40 kPa, 37.45 kPa, 32.4 kPa, and 30.15 kPa. Consequently, the same lengths of linear regions within adjacent fringes of an approximately sinusoidal curve corresponded to different measurement ranges, linearities, and sensitivities. Initial cavity length must be chosen to optimize both signal strength and the PIS studied here in manufacturing this type sensor.

  17. Diamond-like carbon film preparation using a high-repetition nanosecond pulsed glow discharge plasma at gas pressure of 1 kPa generated by a SiC-MOSFET inverter power supply

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yusuke; Ogura, Masataka; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2017-10-01

    A high-repetition nanosecond pulsed glow discharge plasma at a gas pressure of 1 kPa was generated using a SiC-MOSFET inverter power supply for diamond-like carbon (DLC) film preparation. At a high repetition frequency above 50 kHz, the period of the nanosecond voltage pulse became shorter than the decay time of the afterglow plasma, and many ions and radicals remained in the gap space. The deposition rate was 0.1 µm/min, which was 5 times higher than that of a conventional plasma CVD process. An increase in hardness to 13 GPa and a decrease in hydrogen content in the DLC film were confirmed by increasing the repetition frequency to 200 kHz.

  18. Thermodynamic and Structural Properties of liquid Mg2SiO4 at high temperatures and pressure in the range 0-150 GPa from Molecular Dynamics Simulation

    NASA Astrophysics Data System (ADS)

    Martin, B.; Spera, F.; Nevins, D.

    2006-12-01

    Growing interest in the dynamics of magma oceans and melting within the terrestrial planets highlights the need for developing equations of state (EOS) and transport properties of molten silicate multicomponent solutions at high temperature and pressure. We report Molecular Dynamics simulations of liquid Mg2SiO4, an important component of the upper mantle. An interatomic effective pair potential that includes Coulomb forces, Born exponential electron repulsion and van der Waals dipolar attractive forces was used with parameters from Matsui (Mineral. Mag, 58A, 571-572, 1994). 50 state points were studied in the NEV microcanonical ensemble with 8001 particles (1143 formula units) each for 50 ps (1 fs timestep). Liquid densities range from 2750 kg/m3 to 4500 kg/m3 with temperature and pressure in the range 2000- 4500 K and 0-150 GPa, respectively. Atom trajectories were post-processed to obtain a comprehensive view of nearest neighbor coordination statistics, internal energy, isochoric heat capacity, and tracer diffusivities of Mg, Si and O at all state points. Computed potential energies scale linearly in T^{3/5} along isochors facilitating EOS development by allowing robust interpolation. First nearest neighbor coordination statistics show a continuous decrease in ^{[4]}Si and increase in ^{[5]}Si and ^{[6]}Si with increasing pressure along an isotherm. In distinction, the abundance of ^{[1]}O (O with one nearest Si neighbor) is roughly constant at about 70%, with ^{[0]}O and ^{[2]}O both at about 15% as pressure increases along an isotherm. Oxygen tracer diffusivity is ~6.7x10-9 m2/s at 9.8 GPa and 3088 K. Mg and Si tracer diffusivities 1.7 and 0.8 that of oxygen, respectively. Using the Stokes-Einstein and Eyring relations between shear viscosity and oxygen tracer diffusivity, a shear viscosity of ~2.1x10-3 Pa s is estimated for molten Mg2SiO4 at 10 GPa and 3100 K. Liquid density computed by MD compares very well with liquid density inferred from experimental

  19. A film bulk acoustic resonator-based high-performance pressure sensor integrated with temperature control system

    NASA Astrophysics Data System (ADS)

    Zhang, Mengying; Zhao, Zhan; Du, Lidong; Fang, Zhen

    2017-04-01

    This paper presented a high-performance pressure sensor based on a film bulk acoustic resonator (FBAR). The support film of the FBAR chip was made of silicon nitride and the part under the resonator area was etched to enhance the sensitivity and improve the linearity of the pressure sensor. A micro resistor temperature sensor and a micro resistor heater were integrated in the chip to monitor and control the operating temperature. The sensor chip was fabricated, and packaged in an oscillator circuit for differential pressure detection. When the detected pressure ranged from  ‑100 hPa to 600 hPa, the sensitivity of the improved FBAR pressure sensor was  ‑0.967 kHz hPa‑1, namely  ‑0.69 ppm hPa‑1, which was 19% higher than that of existing sensors with a complete support film. The nonlinearity of the improved sensor was less than  ±0.35%, while that of the existing sensor was  ±5%. To eliminate measurement errors from humidity, the temperature control system integrated in the sensor chip controlled the temperature of the resonator up to 75 °C, with accuracy of  ±0.015 °C and power of 20 mW.

  20. Metabolic Acclimation to Anoxia Induced by Low (2-4 kPa Partial Pressure) Oxygen Pretreatment (Hypoxia) in Root Tips of Zea mays

    PubMed Central

    Saglio, Pierre H.; Drew, Malcolm C.; Pradet, Alain

    1988-01-01

    Young intact plants of maize (Zea mays L. cv INRA 508) were exposed to 2 to 4 kilopascals partial pressure oxygen (hypoxic pretreatment) for 18 hours before excision of the 5 millimeter root apex and treatment with strictly anaerobic conditions (anoxia). Hypoxic acclimation gave rise to larger amounts of ATP, to larger ATP/ADP and adenylate energy charge ratios, and to higher rates of ethanol production when excised root tips were subsequently made anaerobic, compared with root tips transferred directly from aerobic to anaerobic media. Improved energy metabolism following hypoxic pretreatment was associated with increased activity of alcohol dehydrogenase (ADH), and induction of ADH-2 isozymes. Roots of Adh1− mutant plants lacked constitutive ADH and only slowly produced ethanol when made anaerobic. Those that were hypoxically pretreated acclimated to anoxia with induction of ADH2 and a higher energy metabolism, and a rate of ethanol production comparable to that of nonmutants. All these responses were insensitive to the presence or absence of NO3−. Additionally, the rate of ethanol production was about 50 times greater than the rate of reduction of NO3− to NO2−. These results indicate that nitrate reductase does not compete effectively with ADH for NADH, or contribute to energy metabolism during anaerobic respiration in this tissue through nitrate reduction. Unacclimated root tips of wild type and Adhl− mutants appeared not to survive more than 8 to 9 hours in strict anoxia; when hypoxically pretreated they tolerated periods under anoxia in excess of 22 hours. Images Fig. 5 PMID:16665894

  1. Safety analysis of high pressure 3He-filled micro-channels for thermal neutron detection.

    SciTech Connect

    Ferko, Scott M.; Galambos, Paul C.; Derzon, Mark Steven; Renzi, Ronald F.

    2008-11-01

    This document is a safety analysis of a novel neutron detection technology developed by Sandia National Laboratories. This technology is comprised of devices with tiny channels containing high pressure {sup 3}He. These devices are further integrated into large scale neutron sensors. Modeling and preliminary device testing indicates that the time required to detect the presence of special nuclear materials may be reduced under optimal conditions by several orders of magnitude using this approach. Also, these devices make efficient use of our {sup 3}He supply by making individual devices more efficient and/or extending the our limited {sup 3}He supply. The safety of these high pressure devices has been a primary concern. We address these safety concerns for a flat panel configuration intended for thermal neutron detection. Ballistic impact tests using 3 g projectiles were performed on devices made from FR4, Silicon, and Parmax materials. In addition to impact testing, operational limits were determined by pressurizing the devices either to failure or until they unacceptably leaked. We found that (1) sympathetic or parasitic failure does not occur in pressurized FR4 devices (2) the Si devices exhibited benign brittle failure (sympathetic failure under pressure was not tested) and (3) the Parmax devices failed unacceptably. FR4 devices were filled to pressures up to 4000 + 100 psig, and the impacts were captured using a high speed camera. The brittle Si devices shattered, but were completely contained when wrapped in thin tape, while the ductile FR4 devices deformed only. Even at 4000 psi the energy density of the compressed gas appears to be insignificant compared to the impact caused by the incoming projectile. In conclusion, the current FR4 device design pressurized up to 4000 psi does not show evidence of sympathetic failure, and these devices are intrinsically safe.

  2. Changing the "Normal Range" for Blood Pressure from 140/90 to 130/Any Improves Risk Assessment.

    PubMed

    Fulks, Michael; Stout, Robert L; Dolan, Vera F

    2015-01-01

    Objective .- Redefine the "normal" reference range for blood pressure from <140/90 to one that more effectively identifies individuals with increased mortality risk. Method .- Data from the recently published 2014 CRL blood pressure study was used. It includes 2,472,706 life insurance applicants tested by Clinical Reference Laboratory from 1993 to 2007 with follow-up for vital status using the September 2011 Social Security Death Master File. Various upper limits of blood pressure (BP in mm Hg) were evaluated to determine if any was superior to the current, commonly used limit of 140/90 in identifying individuals with increased mortality risk. Results .- An alternative reference range using a systolic BP (SBP) <130 with any diastolic BP (DBP) included 84% of life insurance applicants. It had a lower mortality rate and narrower range of relative risk than <140/90, including 89% as many applicants but only 68% as many deaths. This pattern of lives and deaths was consistent across age and sex. Conclusion .- Switching to a "normal" reference range of SBP <130 offers superior risk assessment relative to using BP <140/90 while still including a sufficient percentage of the population.

  3. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-11-01

    Because of the high travel speed, the complex flow dynamics around an aircraft, and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore, these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realised with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 to 800 hPa, and a water vapour concentration range of more than 3 orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements shows an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2 and 5.1% during in-flight operation on the HALO airplane. Under

  4. Tin phase transition in terapascal pressure range described accurately with Quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Nazarov, Roman; Hood, Randolph; Morales, Miguel

    The accurate prediction of phase transitions is one of the most important research areas in modern materials science. The main workhorse for such calculations, Density functional theory (DFT), employs different forms of approximate exchange-correlation functionals which may lead to overstabilization of one phase compared to another, therefore, predict incorrectly phase transition pressures. A recent example of such deficiency has been demonstrated in Sn: no bcc to hcp phase transition has been observed in Sn when dynamically compressed to 1.2 TPa while DFT predicts a transition to occur at 0.16-0.2 TPa. To overcome the limitations of DFT, we have employed diffusion quantum Monte Carlo (DMC) method which treats the many body electron problem directly. In order to get highly accurate results we systematically assess the effect of controllable approximations of DMC such as fixed node approximation, finite-size effects and the use of pseudopotentials. Based on metrologically accurate DMC equation of states we construct the pressure-temperature phase diagram and demonstrate its good agreement with experiment in contrast to DFT calculations.

  5. Simulation of non-ionic surfactant micelle formation across a range of temperature and pressure

    NASA Astrophysics Data System (ADS)

    Custer, Gregory; Das, Payel; Matysiak, Silvina

    Non-ionic surfactants can, at certain concentrations and thermodynamic conditions, aggregate into micelles due to their amphiphilic nature. Our work looks at the formation and behavior of micelles at extremes of temperature and pressure. Due to the large system size and simulation time required to study micelle formation, we have developed a coarse-grained (CG) model of our system. This CG model represents each heavy atom with a single CG bead. We use the multibody Stillinger-Weber potential, which adds a three-body angular penalty to a two-body potential, to emulate hydrogen bonds in the system. We simulate the linear surfactant C12E5 , which has a nonpolar domain of 12 carbons and a polar domain of 5 ethers. Our CG model has been parameterized to match structural properties from all-atom simulations of single and dimer surfactant systems. Simulations were performed using a concentration above the experimental critical micelle concentration at 300K and 1atm. We observe an expected region of stable micelle formation at intermediate temperature, with a breakdown at high and low temperature, as well as at high pressure. The driving forces behind the destabilization of micelles and the mechanism of micelle formation at different thermodynamic conditions will be discussed.

  6. Prevalence and predictors of out-of-range cuff pressure of endotracheal and tracheostomy tubes: a prospective cohort study in mechanically ventilated patients.

    PubMed

    Alzahrani, Amer R; Al Abbasi, Shatha; Abahoussin, Othman Khalid; Al Shehri, Tariq Othman; Al-Dorzi, Hasan M; Tamim, Hani M; Sadat, Musharaf; Arabi, Yaseen M

    2015-10-15

    Maintaining the cuff pressure of endotracheal tubes (ETTs) within 20-30 cmH2O is a standard practice. The aim of the study was to evaluate the effectiveness of standard practice in maintaining cuff pressure within the target range. This was a prospective observational study conducted in a tertiary-care intensive care unit, in which respiratory therapists (RTs) measured the cuff pressure 6 hourly by a handheld manometer. In this study, a research RT checked cuff pressure 2-4 h after the clinical RT measurement. Percentages of patients with cuff pressure levels above and below the target range were calculated. We identified predictors of low-cuff pressure. We analyzed 2120 cuff-pressure measurements. The mean cuff pressure was 27 ± 2 cmH2O by the clinical RT and 21 ± 5 cmH2O by the research RT (p < 0.0001). The clinical RT documented that 98.0 % of cuff pressures were within the normal range. The research RT found the cuff pressures to be within the normal range in only 41.5 %, below the range in 53 % and above the range in 5.5 %. Low cuff pressure was found more common with lower ETT size (OR, 0.34 per 0.5 unit increase in ETT size; 95 % CI, 0.15-0.79) and with lower peak airway pressure (OR per one cm H2O increment, 0.93; 95 % CI, 0.87-0.99) on multivariate analysis. Cuff pressure is frequently not maintained within the target range with low-cuff pressure being very common approximately 3 h after routine measurements. Low cuff pressure was associated with lower ETT size and lower peak airway pressure. There is a need to redesign the process for maintaining cuff pressure within the target range.

  7. Hydro-isomerization of n-hexane on bi-functional catalyst: Effect of total and hydrogen partial pressures

    NASA Astrophysics Data System (ADS)

    Thoa, Dao Thi Kim; Loc, Luu Cam

    2017-09-01

    The effect of both total pressure and hydrogen partial pressure during n-hexane hydro-isomerization over platinum impregnated on HZSM-5 was studied. n-Hexane hydro-isomerization was conducted at atmospheric pressure and 0.7 MPa to observe the influence of total pressure. In order to see the effect of hydrogen partial pressure, the reaction was taken place at different partial pressure of hydrogen varied from 307 hPa to 718 hPa by dilution with nitrogen to keep the total pressure at 0.1 MPa. Physico-chemical characteristics of catalyst were determined by the methods of nitrogen physi-sorption BET, SEM, XRD, TEM, NH3-TPD, TPR, and Hydrogen Pulse Chemi-sorption. Activity of catalyst in the hydro-isomerization of n-hexane was studied in a micro-flow reactor in the temperature range of 225-325 °C; the molar ratio H2/ hydrocarbon: 5.92, concentration of n-hexane: 9.2 mol.%, GHSV 2698 h-1. The obtained catalyst expressed high acid density, good reducing property, high metal dispersion, and good balance between metallic and acidic sites. It is excellent contact for n-hexane hydro-isomerization. At 250 °C, n-hexane conversion and selectivity were as high as 59-76 % and 85-99 %, respectively. It was found that catalytic activity was promoted either by total pressure or hydrogen partial pressure. At total pressure of 0.7 MPa while hydrogen partial pressure of 718 hPa, catalyst produced 63 RON liquid product containing friendly environmental iso-paraffins which is superior blending stock for green gasoline. Hydrogen did not only preserve catalyst actives by depressing hydrocracking and removing coke precursors but also facilitated hydride transfer step in the bi-functional bi-molecular mechanism.

  8. Bi-stability of micro-plates: A sensitive mechanism for differential pressure measurements

    NASA Astrophysics Data System (ADS)

    Sajadi, Banafsheh; Goosen, Johannes Hans; van Keulen, Fred

    2017-09-01

    The electrostatic instability (pull-in) of a flat electrode in a parallel plate capacitor has been shown to be highly sensitive to external mechanical loads such as pressure. In this paper, we substantiate the possibility of prompting additional unstable configurations in such a system, with a remarkable sensitivity to the applied pressure. This additional instability has significant advantageous properties for sensing purposes. In addition to the high sensitivity and robustness of the pull-in voltage measurements, it can be adjusted so that after the unstable configuration is met, a snap-through to a new stable configuration occurs. As a result of this bi-stable behavior, the contact between the electrodes, which is the main drawback of pull-in phenomena, will be easily avoided. The results of this paper particularly suggest the suitability of this mechanism for two different methods of pressure measurements.

  9. Long-range correlations of microseism-band pressure fluctuations in the ocean

    NASA Astrophysics Data System (ADS)

    Ball, Justin S.; Godin, Oleg A.; Evers, Läslo G.; Lv, Cheng

    2016-08-01

    We investigate the spatial coherence of underwater ambient noise using a yearlong time-series measured off Ascension Island. Qualitative agreement with observed cross-correlations is achieved using a simple range-dependent model, constrained by earlier, active tomographic studies in the area. In particular, the model correctly predicts the existence of two weakly dispersive normal modes in the microseism frequency range, with the group speed of one of the normal modes being smaller than the sound speed in water. The agreement justifies our interpretation of the peaks of the measured cross-correlation function of ambient noise as modal arrivals, with dispersion that is sensitive to crustal velocity structure. Our observations are consistent with Scholte to Moho head wave coupled propagation, with double mode conversion occurring due to the bathymetric variations between receivers. We thus demonstrate the feasibility of interrogating crustal properties using noise interferometry of moored hydrophone data at ranges in excess of 120 km.

  10. Characteristics of a micro-gap argon barrier discharge excited by a saw-tooth voltage at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Li, Xuechen; Zhang, Qi; Jia, Pengying; Chu, Jingdi; Zhang, Panpan; Dong, Lifang

    2017-03-01

    Using two water electrodes, a micro-gap dielectric barrier discharge excited by a saw-tooth voltage is investigated in atmospheric pressure argon. Through electrical and optical measurements, it is found that, at a lower driving frequency, a stepped discharge mode is obtained per half voltage cycle. Moreover, the duration and amplitude of the current plateau increase with the increase in the applied peak voltage. With the increase in the driving frequency, the stepped discharge mode transits into a pulsed one after a multi-peak mode. During this process, a diffuse discharge at a lower frequency transits into a filamentary one at a higher frequency. Temporal evolutions of the discharges are investigated axially based on fast photography. It is found that the stepped mode is in atmospheric pressure Townsend discharge (APTD) regime. However, there is a transition from APTD to atmospheric pressure glow discharge for the pulsed mode. Spectral intensity ratio of 391.4 nm to 337.1 nm is used to determine the averaged electron energy, which decreases with increasing peak voltage or driving frequency.

  11. A comparison between micro hollow cathode discharges and atmospheric pressure plasma jets in Ar/O2 gas mixtures

    NASA Astrophysics Data System (ADS)

    Lazzaroni, C.; Chabert, P.

    2016-12-01

    Using global models, micro hollow cathode discharges (MHCDs) are compared to radiofrequency atmospheric pressure plasma jets (APPJs) in terms of reactive oxygen species (ROS) production. Ar/O2 gas mixtures are investigated, typically with a small percentage of oxygen in argon. The same chemical reaction set, involving 17 species and 128 chemical reactions in the gas phase, is used for both devices, operated in the typical geometries previously published; the APPJ is driven by a radiofrequency voltage across a 1 mm gap, at atmospheric pressure, while the MHCD is driven by a DC voltage source, at 100 Torr and in a 400 μm hole. The MHCD may be operated either in the self-pulsing or in the normal (stationary) regime, depending on the driving voltage. The comparison shows that in both regimes, the MHCD produces larger amounts of \\text{O}2\\ast , while the APPJ produces predominantly reactive oxygen ground state species, \\text{O} and {{\\text{O}}3} . These large differences in ROS composition are mostly due to the higher plasma density produced in the MHCD. The difference in operating pressure is a second order effect.

  12. Dynamic Pressure Calibration Standard

    NASA Technical Reports Server (NTRS)

    Schutte, P. C.; Cate, K. H.; Young, S. D.

    1986-01-01

    Vibrating columns of fluid used to calibrate transducers. Dynamic pressure calibration standard developed for calibrating flush diaphragm-mounted pressure transducers. Pressures up to 20 kPa (3 psi) accurately generated over frequency range of 50 to 1,800 Hz. System includes two conically shaped aluminum columns one 5 cm (2 in.) high for low pressures and another 11 cm (4.3 in.) high for higher pressures, each filled with viscous fluid. Each column mounted on armature of vibration exciter, which imparts sinusoidally varying acceleration to fluid column. Signal noise low, and waveform highly dependent on quality of drive signal in vibration exciter.

  13. Direct Numerical Simulation and Theories of Wall Turbulence with a Range of Pressure Gradients

    NASA Technical Reports Server (NTRS)

    Coleman, G. N.; Garbaruk, A.; Spalart, P. R.

    2014-01-01

    A new Direct Numerical Simulation (DNS) of Couette-Poiseuille flow at a higher Reynolds number is presented and compared with DNS of other wall-bounded flows. It is analyzed in terms of testing semi-theoretical proposals for universal behavior of the velocity, mixing length, or eddy viscosity in pressure gradients, and in terms of assessing the accuracy of two turbulence models. These models are used in two modes, the traditional one with only a dependence on the wall-normal coordinate y, and a newer one in which a lateral dependence on z is added. For pure Couette flow and the Couette-Poiseuille case considered here, this z-dependence allows some models to generate steady streamwise vortices, which generally improves the agreement with DNS and experiment. On the other hand, it complicates the comparison between DNS and models.

  14. Structure and growth kinetics of the oxidation process of Fe(001) whisker surfaces over a 10-decade pressure range

    NASA Astrophysics Data System (ADS)

    Ferrer, Salvador; Robach, Odile; Balmes, Olivier; Isern, Helena; Popa, Iona; Ackerman, Marcelo

    2010-10-01

    Fe(001) surfaces of whiskers of good crystalline quality were oxidized in a pressure range from 10 - 7 mbar to 1 bar at different temperatures. Epitaxial Fe 3O 4 and FeO thin films with negligible strain were grown depending on the oxidation temperatures. The kinetics of the oxide thickness growth was measured and compared with the predictions of the Fromhold-Cook theory for oxidation of metals. Some discrepancies were found and a possible explanation is presented.

  15. Pressure-accelerated azide-alkyne cycloaddition: micro capillary versus autoclave reactor performance.

    PubMed

    Borukhova, Svetlana; Seeger, Andreas D; Noël, Timothy; Wang, Qi; Busch, Markus; Hessel, Volker

    2015-02-01

    Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard conditions are well established. Herein, we apply novel-process-window (NPWs) principles, such as intensification of intrinsic kinetics of a reaction using high temperature, pressure, and concentration, on azide-alkyne cycloaddition towards synthesis of Rufinamide precursor. We applied three main activation methods (i.e., uncatalyzed batch, uncatalyzed flow, and catalyzed flow) on uncatalyzed and catalyzed azide-alkyne cycloaddition. We compare the performance of two reactors, a specialized autoclave batch reactor for high-pressure operation up to 1800 bar and a capillary flow reactor (up to 400 bar). A differentiated and comprehensive picture is given for the two reactors and the three methods of activation. Reaction speedup and consequent increases in space-time yields is achieved, while the process window for favorable operation to selectively produce Rufinamide precursor in good yields is widened. The best conditions thus determined are applied to several azide-alkyne cycloadditions to widen the scope of the presented methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. New Micro-Method for Prediction of Vapor Pressure of Energetic Materials

    DTIC Science & Technology

    2014-07-01

    Triaminoguanidinium-1-methyl-5-nitriminotetrazolate 171 –5.5 –5.4 27 Hydrazinebistetrazole 206 –7.5 –7.6 29 TAGDN (Triaminoguanidinium-5-dinitrate) 81 –0.2 0.5...G.R.B. Vapor Pressure Determination for Several Polychlorodioxins by Two Gas Saturation Methods, Chemosphere , Volume 15, Issues 9–12, 1986, Pages 2073

  17. Three distinct modes in a surface micro-discharge in atmospheric pressure He + N{sub 2} mixtures

    SciTech Connect

    Li, Dong; Liu, Dingxin He, Tongtong; Li, Qiaosong; Wang, Xiaohua; Kong, Michael G.

    2015-12-15

    A surface micro-discharge in atmospheric pressure He + N{sub 2} mixtures is studied in this paper with an emphasis on the discharge modes. With the N{sub 2} admixture increasing from 0.1% to 20%, the discharge evolves from a spatially diffuse mode to a filamentary mode during positive half-cycles of the applied voltage. However during the negative half-cycles, an additional patterned mode emerges between the diffuse and the filamentary modes, which has not been reported before to exist in surface micro-discharges. In the diffuse and patterned modes, the plasmas cover almost the entirety of the mesh area during one cycle after plasma ignition in all mesh elements, and the discharge power increases linearly with the applied voltage. In contrast, plasma coverage of the mesh area is only partial in the filamentary mode and the plasma is more unstable with the discharge power increasing exponentially with the applied voltage. As the surface micro-discharge evolves through the three modes, the density of excited species changes significantly, for instance, the density of N{sub 2}{sup +}(B) drops by ∼20-fold from [N{sub 2}] = 0.2% to 20%. The N{sub 2}{sup +}(B) is predicted to be generated mainly through successive processes of Penning ionization by helium metastables and electron-impact excitation of N{sub 2}{sup +}(X), the latter is most responsible for the density decrease of N{sub 2}{sup +}(B) because much more N{sub 2}{sup +}(X) is converted to N{sub 4}{sup +}(X) as the increase of N{sub 2} fraction. Also, the electron density and electron temperature decrease with the discharge mode transition.

  18. HIgh-Q Optical Micro-cavity Resonators as High Sensitive Bio-chemical and Ultrasonic Sensors

    NASA Astrophysics Data System (ADS)

    Ling, Tao

    Optical micro-cavity resonators have quickly emerged in the past few years as a new sensing platform in a wide range of applications, such as bio-chemical molecular detection, environmental monitoring, acoustic and electromagnetic waves detection. In this thesis, we will mainly focus on developing high sensitivity silica micro-tube resonator bio-chemical sensors and high sensitivity polymer micro-ring resonator acoustic sensors. In high sensitivity silica micro-tube resonator bio-chemical sensors part: We first demonstrated a prism coupled silica micro-tube bio-chemical sensing platform to overcome the reliability problem in a fiber coupled thin wall silica micro-tube sensing platform. In refractive index sensing experiment, a unique resonance mode with sensitivity around 600nm/refractive index unit (RIU) has been observed. Surface sensing experiments also have been performed in this platform to detect lipid monolayer, lipid bilayer, electrostatic self assemble layer-by-layer as well as the interaction between the lipid bilayer and proteins. Then a theoretical study on various sensing properties on the silica micro-tube based sensing platform has been realized. Furthermore, we have proposed a coupled cavity system to further enhance the device's sensitivity above 1000nm/RIU. In high sensitivity polymer micro-ring resonator acoustic sensors part: We first presented a simplified fabrication process and realized a polymer microring with a Q factor around 6000. The fabricated device has been used to detect acoustic wave with noise equivalent pressure (NEP) around 230Pa over 1-75MHz frequency rang, which is comparable to state-of-art piezoelectric transducer and the device's frequency response also have been characterized to be up to 90MHz. A new fabrication process combined with resist reflow and thermal oxidation process has been used to improve the Q factor up to 10 5 and the device's NEP has been tested to be around 88Pa over 1-75MHz range. Further improving the

  19. Flow pattern, void fraction and pressure drop of two-phase air-water flow in a horizontal circular micro-channel

    SciTech Connect

    Saisorn, Sira; Wongwises, Somchai

    2008-01-15

    Adiabatic two-phase air-water flow characteristics, including the two-phase flow pattern as well as the void fraction and two-phase frictional pressure drop, in a circular micro-channel are experimentally studied. A fused silica channel, 320 mm long, with an inside diameter of 0.53 mm is used as the test section. The test runs are done at superficial velocity of gas and liquid ranging between 0.37-16 and 0.005-3.04 m/s, respectively. The flow pattern map is developed from the observed flow patterns i.e. slug flow, throat-annular flow, churn flow and annular-rivulet flow. The flow pattern map is compared with those of other researchers obtained from different working fluids. The present single-phase experiments also show that there are no significant differences in the data from the use of air or nitrogen gas, and water or de-ionized water. The void fraction data obtained by image analysis tends to correspond with the homogeneous flow model. The two-phase pressure drops are also used to calculate the frictional multiplier. The multiplier data show a dependence on flow pattern as well as mass flux. A new correlation of two-phase frictional multiplier is also proposed for practical application. (author)

  20. High pressure apparatus for magnetization measurements

    SciTech Connect

    Uwatoko, Y.; Hotta, T.; Mori, H.

    1997-10-01

    A hydrostatic high pressure micro cell for studying heavy-fermion materials in a commercial magnetometer is developed. Experiments of pressures up to 10 kbar and temperature range 2 K {le} T {le} 300 K have been carried out. The sensitivity of measurement of under high pressure is as same as ambient pressure one within experimental error.

  1. A low-power pressure-and temperature-programmed separation system for a micro gas chromatograph.

    SciTech Connect

    Sacks, Richard D. (University of Michigan, Ann Arbor, MI); Robinson, Alex Lockwood (Advanced Sensor Technologies, Albuquerque, NM); Lambertus, Gordon R. (University of Michigan, Ann Arbor, MI); Potkay, Joseph A. (University of Michigan, Ann Arbor, MI); Wise, Kensall D. (University of Michigan, Ann Arbor, MI)

    2006-10-01

    This thesis presents the theory, design, fabrication and testing of the microvalves and columns necessary in a pressure- and temperature-programmed micro gas chromatograph ({micro}GC). Two microcolumn designs are investigated: a bonded Si-glass column having a rectangular cross section and a vapor-deposited silicon oxynitride (Sion) column having a roughly circular cross section. Both microcolumns contain integrated heaters and sensors for rapid, controlled heating. The 3.2 cm x 3.2 cm, 3 m-long silicon-glass column, coated with a non-polar polydimethylsiloxane (PDMS) stationary phase, separates 30 volatile organic compounds (VOCs) in less than 6 min. This is the most efficient micromachined column reported to date, producing greater than 4000 plates/m. The 2.7 mm x 1.4 mm Sion column eliminates the glass sealing plate and silicon substrate using deposited dielectrics and is the lowest power and fastest GC column reported to date; it requires only 11 mW to raise the column temperature by 100 C and has a response time of 11s and natural temperature ramp rate of 580 C/min. A 1 m-long PDMS-coated Sion microcolumn separates 10 VOCs in 52s. A system-based design approach was used for both columns.

  2. High pressure capillary micro-fluidic valve device and a method of fabricating same

    DOEpatents

    Crocker, Robert W.; Caton, Pamela F.; Gerhardt, Geoff C.

    2007-04-17

    A freeze-thaw valve and a method of micro-machining the freeze-thaw valve is provided and includes a valve housing, wherein the valve housing defines a housing cavity and includes a housing inlet, a housing vent, a capillary tubing inlet and a capillary tubing outlet. A valve body is provided, at least a portion of which is lithographically constructed, wherein the valve body includes a refrigerant inlet, a refrigerant outlet and an expansion chamber. The expansion chamber is disposed to communicate the refrigerant inlet with the refrigerant outlet and includes a restriction region having a flow restriction. Additionally, the valve body is disposed within the housing cavity to form an insulating channel between the valve housing and the valve body.

  3. Inertial-range kinetic turbulence in pressure-anisotropic astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Kunz, M. W.; Schekochihin, A. A.; Chen, C. H. K.; Abel, I. G.; Cowley, S. C.

    2015-10-01

    > A theoretical framework for low-frequency electromagnetic (drift-)kinetic turbulence in a collisionless, multi-species plasma is presented. The result generalises reduced magnetohydrodynamics (RMHD) and kinetic RMHD (Schekochihin et al., Astrophys. J. Suppl. Ser., vol. 182, 2009, pp. 310-377) to the case where the mean distribution function of the plasma is pressure-anisotropic and different ion species are allowed to drift with respect to each other - a situation routinely encountered in the solar wind and presumably ubiquitous in hot dilute astrophysical plasmas such as the intracluster medium. Two main objectives are achieved. First, in a non-Maxwellian plasma, the relationships between fluctuating fields (e.g. the Alfvén ratio) are order-unity modified compared to the more commonly considered Maxwellian case, and so a quantitative theory is developed to support quantitative measurements now possible in the solar wind. Beyond these order-unity corrections, the main physical feature of low-frequency plasma turbulence survives the generalisation to non-Maxwellian distributions: Alfvénic and compressive fluctuations are energetically decoupled, with the latter passively advected by the former; the Alfvénic cascade is fluid, satisfying RMHD equations (with the Alfvén speed modified by pressure anisotropy and species drifts), whereas the compressive cascade is kinetic and subject to collisionless damping (and for a bi-Maxwellian plasma splits into three independent collisionless cascades). Secondly, the organising principle of this turbulence is elucidated in the form of a conservation law for the appropriately generalised kinetic free energy. It is shown that non-Maxwellian features in the distribution function reduce the rate of phase mixing and the efficacy of magnetic stresses, and that these changes influence the partitioning of free energy amongst the various cascade channels. As the firehose or mirror instability thresholds are approached, the dynamics

  4. Inhibition of MicroRNA-146a and Overexpression of Its Target Dihydrolipoyl Succinyltransferase Protect Against Pressure Overload-Induced Cardiac Hypertrophy and Dysfunction.

    PubMed

    Heggermont, Ward A; Papageorgiou, Anna-Pia; Quaegebeur, Annelies; Deckx, Sophie; Carai, Paolo; Verhesen, Wouter; Eelen, Guy; Schoors, Sandra; van Leeuwen, Rick; Alekseev, Sergey; Elzenaar, Ies; Vinckier, Stefan; Pokreisz, Peter; Walravens, Ann-Sophie; Gijsbers, Rik; Van Den Haute, Chris; Nickel, Alexander; Schroen, Blanche; van Bilsen, Marc; Janssens, Stefan; Maack, Christoph; Pinto, Yigal; Carmeliet, Peter; Heymans, Stephane

    2017-08-22

    Cardiovascular diseases remain the predominant cause of death worldwide, with the prevalence of heart failure continuing to increase. Despite increased knowledge of the metabolic alterations that occur in heart failure, novel therapies to treat the observed metabolic disturbances are still lacking. Mice were subjected to pressure overload by means of angiotensin-II infusion or transversal aortic constriction. MicroRNA-146a was either genetically or pharmacologically knocked out or genetically overexpressed in cardiomyocytes. Furthermore, overexpression of dihydrolipoyl succinyltransferase (DLST) in the murine heart was performed by means of an adeno-associated virus. MicroRNA-146a was upregulated in whole heart tissue in multiple murine pressure overload models. Also, microRNA-146a levels were moderately increased in left ventricular biopsies of patients with aortic stenosis. Overexpression of microRNA-146a in cardiomyocytes provoked cardiac hypertrophy and left ventricular dysfunction in vivo, whereas genetic knockdown or pharmacological blockade of microRNA-146a blunted the hypertrophic response and attenuated cardiac dysfunction in vivo. Mechanistically, microRNA-146a reduced its target DLST-the E2 subcomponent of the α-ketoglutarate dehydrogenase complex, a rate-controlling tricarboxylic acid cycle enzyme. DLST protein levels significantly decreased on pressure overload in wild-type mice, paralleling a decreased oxidative metabolism, whereas DLST protein levels and hence oxidative metabolism were partially maintained in microRNA-146a knockout mice. Moreover, overexpression of DLST in wild-type mice protected against cardiac hypertrophy and dysfunction in vivo. Altogether we show that the microRNA-146a and its target DLST are important metabolic players in left ventricular dysfunction. © 2017 American Heart Association, Inc.

  5. Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

    SciTech Connect

    Xiao, Hai; Tsai, Hai-Lung; Dong, Junhang

    2014-09-30

    This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologies that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.

  6. Development and characterization of a pressure-sensitive luminescent coating based on Pt(II)-porphyrin self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    Sakamura, Y.; Suzuki, T.; Kawabata, S.

    2015-06-01

    A pressure-sensitive luminescent coating (PSLC) applicable to the visualization of pressure distributions in micro-scale flow devices was developed. Pt(II)-porphyrin was synthesized and covalently attached to the surface of indium tin oxide (ITO) glass plates by a self-assembled monolayer (SAM) process. The UV-visible absorption spectrum, pressure and temperature sensitivities and photostability of the PSLC were then measured to characterize the developed PSLC. It was found that (a) the chemisorption of the porphyrin did not greatly perturb the molecular orbitals of the porphyrin responsible for its photophysics, (b) the pressure dependency of the luminescent intensity of the PSLC obeyed a power function curve and the pressure sensitivities at 273, 293, 313 and 333 K were obtained in the pressure range from 5 to 120 kPa, (c) the luminescent intensity of the PSLC almost linearly decreased with temperature and the temperature sensitivities at 5, 40, 100 and 120 kPa evaluated in the temperature range from 273 to 333 K were -0.67, -0.72, -0.75 and -0.78%/K, respectively and (d) the decrease in the luminescent intensity of the PSLC after a 30 min exposure to an excitation light was 1.23% of its initial intensity and much smaller than that of Pt(II)-porphyrin absorbed on a TLC (thin-layer chromatography) sheet.

  7. Perfusion pressure-dependent recovery of cortical spreading depression is independent of tissue oxygenation over a wide physiologic range.

    PubMed

    Sukhotinsky, Inna; Yaseen, Mohammad A; Sakadzić, Sava; Ruvinskaya, Svetlana; Sims, John R; Boas, David A; Moskowitz, Michael A; Ayata, Cenk

    2010-06-01

    Spreading depression (SD) is a slowly propagating wave of transient neuronal and glial depolarization that develops after stroke, trauma and subarachnoid hemorrhage. In compromised tissue, repetitive SD-like injury depolarizations reduce tissue viability by worsening the mismatch between blood flow and metabolism. Although the mechanism remains unknown, SDs show delayed electrophysiological recovery within the ischemic penumbra. Here, we tested the hypothesis that the recovery rate of SD can be varied by modulating tissue perfusion pressure and oxygenation. Systemic blood pressure and arterial pO(2) were simultaneously manipulated in anesthetized rats under full physiologic monitoring. We found that arterial hypotension doubled the SD duration, whereas hypertension reduced it by a third compared with normoxic normotensive rats. Hyperoxia failed to shorten the prolonged SD durations in hypotensive rats, despite restoring tissue pO(2). Indeed, varying arterial pO(2) (40 to 400 mm Hg) alone did not significantly influence SD duration, whereas blood pressure (40 to 160 mm Hg) was inversely related to SD duration in compromised tissue. These data suggest that cerebral perfusion pressure is a critical determinant of SD duration independent of tissue oxygenation over a wide range of arterial pO(2) levels, and that hypotension may be detrimental in stroke and subarachnoid hemorrhage, where SD-like injury depolarizations have been observed.

  8. A Computational Fluid Dynamics Study of Transitional Flows in Low-Pressure Turbines under a Wide Range of Operating Conditions

    NASA Technical Reports Server (NTRS)

    Suzen, Y. B.; Huang, P. G.; Ashpis, D. E.; Volino, R. J.; Corke, T. C.; Thomas, F. O.; Huang, J.; Lake, J. P.; King, P. I.

    2007-01-01

    A transport equation for the intermittency factor is employed to predict the transitional flows in low-pressure turbines. The intermittent behavior of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, mu(sub p) with the intermittency factor, gamma. Turbulent quantities are predicted using Menter's two-equation turbulence model (SST). The intermittency factor is obtained from a transport equation model which can produce both the experimentally observed streamwise variation of intermittency and a realistic profile in the cross stream direction. The model had been previously validated against low-pressure turbine experiments with success. In this paper, the model is applied to predictions of three sets of recent low-pressure turbine experiments on the Pack B blade to further validate its predicting capabilities under various flow conditions. Comparisons of computational results with experimental data are provided. Overall, good agreement between the experimental data and computational results is obtained. The new model has been shown to have the capability of accurately predicting transitional flows under a wide range of low-pressure turbine conditions.

  9. Equation of State of Shock Compressed Gases at Megabar Pressure Range

    NASA Astrophysics Data System (ADS)

    Gryaznov, Victor; Iosilevskiy, Igor; Fortov, Vladimir

    2011-06-01

    The model for equation of state of warm dense matter is developed in frames of ``chemical picture.'' Shock compressed gas is considered as a multi-component strongly interacted mixture of atoms, molecules, ions and electrons. Coulomb interaction of charged particles, short-range repulsion and attraction of heavy particles so as partial degeneracy of free electrons are taken into account. Contribution of repulsion of atoms and molecules to thermodynamic functions is considered in frames of extended soft-sphere model and corresponds to non-empirical atom-atomic approximation. The modified pseudopotential model is used for description of interaction of charged particles.The results of calculation of principal Hugoniots of hydrogen, deuterium and nitrogen together with calculation of thermodynamics for reshock states and third-shock reverberation are presented. The calculation results are compared with gas-gun, explosive, magnetically launched flyer-plate and laser experiments so as with the results of the first principle modeling.

  10. Effect of pressure on the micro-explosion of water/oil emulsion droplets over a hot plate

    SciTech Connect

    Cho, P. ); Law, C.K. ); Mizomoto, M. )

    1991-02-01

    The purpose of the present investigation is experimentally to study the micro-explosion behavior of water/oil emulsion droplets over a hot plate in general, and the effect of pressure on this droplet/plate system in particular. The technological relevance of this study stems from the interest in direct injection high-compression-ratio engines because droplet/wall interaction is believed to be an important process within these engines, and because water/oil emulsion is most suitable for application with the heavier oils used by them. From the fundamental viewpoint it is not clear a priori that insights gained from results of freely falling droplets can be readily applied to the present system. This is because droplet gasification behavior over a hot plate (commonly known as the Leidenfrost phenomenon) is a nonmonotonic one. Specifically, for a droplet originally in contact with the plate, with increasing plate temperature the droplet lifetime will first decrease, then increase rapidly as the droplet attempts to levitate itself by its outgoing vapor, and finally decrease gradually when it is in the totally levitated mode. Furthermore, a change in pressure not only will shift the transition plate temperatures for the different gasification modes, but it can also conceivably alter the nucleation mode of the superheated water microdroplets depending on whether the emulsion droplet is in physical contact with the plate.

  11. [Applications of multi-micro-volume pressure-assisted derivatization reaction device for analysis of polar heterocyclic aromatic amines by gas chromatography-mass spectrometry].

    PubMed

    Wang, Yiru; Chen, Fangxiang; Shi, Yamei; Tan, Connieal; Chen, Xi

    2013-01-01

    A multi-micro-volume pressure-assisted derivatization reaction device has been designed and made for the silylation derivatization of polar heterocyclic aromatic amines by N-(tert-butyldimethylsilyl )-N-methyl-trifluoroacetamide (MTBSTFA) with 1% catalyst tert-butyldimethylchlorosilane (TBDMCS) at a high temperature. The tert-butyldimethylsilyl derivatives then could be automatically analyzed by gas chromatography-mass spectrometry. Using the pressure-assisted device, the silylation reaction may occur at a temperature higher than the boiling points of the reagents, and several micro-volume samples can be simultaneously pretreated in the same device to shorten the sample-preparation time and to improve the repeatability. The derivatization conditions including the headspace volume of the vial, the evaporative surface area of the reagent, derivatization temperature and time have been discussed for the use of the pressure-assisted device. The experimental results proved that the device is an effective way for the simultaneous derivatization of several micro-volume samples at a high temperature. Compared with a common device, the derivative amounts were obviously increased when using the pressure-assisted device at 90 degrees C. Quantitative derivatization can be achieved even at 150 degrees C while there was no common device could be applied at such a high temperature due to the heavy losses of reagents by evaporation. However, no obviously higher reaction speed has been observed in such a circumstance with a higher temperature and a higher pressure using the pressure-assisted device.

  12. Unified one-dimensional model of bounded plasma with nonzero ion temperature in a broad pressure range

    SciTech Connect

    Palacio Mizrahi, J. H.; Gurovich, V. Tz.; Krasik, Ya. E.

    2013-03-15

    A one-dimensional model for steady state plasmas bounded either between large parallel walls, or by a cylinder or a sphere, valid in a wide range of gas pressures, is considered. The model includes nonzero ion temperature, inertial terms in the ion momentum equations, and allows one to calculate the plasma electron temperature and ion current density reaching the wall, as well as the spatial distributions of the ion fluid velocity, plasma density, and plasma potential in the plasma bulk. In addition, the effect of electron inertia is analyzed. The model includes as particular cases several earlier models that were based on a similar set of differential equations, but that are restricted to a specific pressure regime (low, intermediate, or high). Analytical solution is found in planar geometry, and numerical solution is given in cylindrical and spherical geometry. The results obtained are compared with those of earlier models and the differences are analyzed.

  13. The shock Hugoniot of liquid hydrazine in the pressure range of 3.1 to 21.4 GPa

    SciTech Connect

    Garcia, B.O.; Persson, P-A.

    1996-10-01

    Impedance matching was used; the technique was similar to Richard Dick`s. Shock pressures were produced using a plane wave explosive driver with different explosives and different reference materials against liq. hydrazine. Velocity of shock wave in the liquid and free surface velocity of the reference material were measured using different pin contact techniques. The experimental Hugoniot appears smooth, with no indication of a phase change. The shock Hugoniot of liq. hydrazine was compared against 3 other liquid Hugoniots (liq. NH3, water, CCl4) and is closest to that for water and in between NH3 and CCl4. The hydrazine Hugoniot was also compared to the ``Universal`` Hugoniot for liquids. This universal Hugoniot is not a good approximation for the liq. hydrazine in this pressure range.

  14. Experimental Studies of Diestrol-Micro Emulsion Fuel in a Direct Injection Compression Ignition Engine under Varying Injection Pressures and Timings

    NASA Astrophysics Data System (ADS)

    Kannan, Gopal Radhakrishnan

    2017-03-01

    The research work on biodiesel becomes more attractive in the context of limited availability of petroleum fuels and rapid increase of harmful emissions from diesel engine using conventional fossil fuels. The present investigation has dealt with the influence of biodiesel-diesel-ethanol (diestrol) water micro emulsion fuel (B60D20E20M) on the performance, emission and combustion characteristics of a diesel engine under different injection pressure and timing. The results revealed that the maximum brake thermal efficiency of 32.4% was observed at an injection pressure of 260 bar and injection timing of 25.5°bTDC. In comparison with diesel, micro emulsion fuel showed reduction in carbon monoxide (CO) and total hydrocarbon (THC) by 40 and 24%, respectively. Further, micro emulsion fuel decreased nitric oxide (NO) emission and smoke emission by 7 and 20.7%, while the carbon dioxide (CO2) emission is similar to that of diesel.

  15. Fused micro-knots

    NASA Astrophysics Data System (ADS)

    Shahal, Shir; Linzon, Yoav; Fridman, Moti

    2017-02-01

    We present fusing of fiber micro-knot by CO2 laser which fixes the micro-fibers in place and stabilizing the micro-knot shape, size and orientation. This fusing enables tuning of the coupling strength, the free-spectral range and the birefringence of the fiber micro-knot. Fused micro-knots are superior over regular micro-knots and we believe that fusing of micro-knots should be a standard procedure in fabricating fiber micro-knots.

  16. Hydrostatic Pressure Regulates MicroRNA Expression Levels in Osteoarthritic Chondrocyte Cultures via the Wnt/β-Catenin Pathway

    PubMed Central

    Cheleschi, Sara; De Palma, Anna; Pecorelli, Alessandra; Pascarelli, Nicola Antonio; Valacchi, Giuseppe; Belmonte, Giuseppe; Carta, Serafino; Galeazzi, Mauro; Fioravanti, Antonella

    2017-01-01

    Mechanical loading and hydrostatic pressure (HP) regulate chondrocytes’ metabolism; however, how mechanical stimulation acts remain unclear. MicroRNAs (miRNAs) play an important role in cartilage homeostasis, mechanotransduction, and in the pathogenesis of osteoarthritis (OA). This study investigated the effects of a cyclic HP (1–5 MPa), in both normal and OA human chondrocytes, on the expression of miR-27a/b, miR-140, miR-146a/b, and miR-365, and of their target genes (MMP-13, ADAMTS-5, IGFBP-5, and HDAC-4). Furthermore, we assessed the possible involvement of Wnt/β-catenin pathway in response to HP. Chondrocytes were exposed to HP for 3h and the evaluations were performed immediately after pressurization, and following 12, 24, and 48 h. Total RNA was extracted and used for real-time PCR. β-catenin was detected by Western blotting analysis and immunofluorescence. In OA chondrocytes, HP induced a significant increase (p < 0.01) of the expression levels of miR-27a/b, miR-140, and miR-146a, and a significant reduction (p < 0.01) of miR-365 at all analyzed time points. MMP-13, ADAMTS-5, and HDAC-4 were significantly downregulated following HP, while no significant modification was found for IGFBP-5. β-catenin levels were significantly increased (p < 0.001) in OA chondrocytes at basal conditions and significantly reduced (p < 0.01) by HP. Pressurization did not cause any significant modification in normal cells. In conclusion, in OA chondrocytes, HP restores the expression levels of some miRNAs, downregulates MMP-13, ADAMTS-5, and HDAC-4, and modulates the Wnt/β-catenin pathway activation. PMID:28085114

  17. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season

    PubMed Central

    Zhang, Dalong; Zhang, Zhongdian; Li, Jianming; Chang, Yibo; Du, Qingjie; Pan, Tonghua

    2015-01-01

    The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L.) productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1) without environment control and (2) with a micro-fog system operating when the air vapor pressure deficit (VPD) of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR) of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR), and to a lesser extent caused by leaf area ratio (LAR). Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season. PMID:26221726

  18. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season.

    PubMed

    Zhang, Dalong; Zhang, Zhongdian; Li, Jianming; Chang, Yibo; Du, Qingjie; Pan, Tonghua

    2015-01-01

    The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L.) productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1) without environment control and (2) with a micro-fog system operating when the air vapor pressure deficit (VPD) of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR) of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR), and to a lesser extent caused by leaf area ratio (LAR). Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season.

  19. Body tissue activation using micro-spot atmospheric pressure plasma source

    NASA Astrophysics Data System (ADS)

    Kishimoto, Takumi; Hirata, Takamichi; Tsutsui, Chihiro; Akiya, Masahiro; Mori, Akira

    2012-10-01

    Experiments have been performed involving directly irradiating body tissues with atmospheric pressure plasma for various medical engineering applications of plasmas. Plasma irradiation was used to burn back dermis of rats. Then, healing and improvement of the scald areas were observed. Additionally, we devoted attention to the angiogenesis, which is a key component of the healing mechanism. Plasma irradiated rats and non treatment were performed an intravenous injection of fluorescein isothiocyanate (FITC) labelled tomato-lectin. The neo-vascular vessels were observed by a confocal laser scanning microscopy, and the quantities were calculated. Each quantity was the non treatment: 9.2 +/-- 0.77 and plasma irradiation: 18.4 +/-- 2.9. These data indicates that direct plasma irradiation involving ion/radical may promote angiogenesis, and it promotes living-body activation.

  20. Blood pressure and expression of microRNAs in whole blood

    PubMed Central

    Zhang, Zhou; Kresovich, Jacob K.; Zheng, Yinan; Zhong, Jia; Patel, Ruchi; Zhang, Wei; Liu, Lei; Dou, Chang; McCracken, John P.; Díaz, Anaité; Motta, Valeria; Sanchez-Guerra, Marco; Bian, Shurui; Bertazzi, Pier Alberto; Schwartz, Joel; Baccarelli, Andrea A.

    2017-01-01

    Background Blood pressure (BP) is a complex, multifactorial clinical outcome driven by genetic susceptibility, behavioral choices, and environmental factors. Many molecular mechanisms have been proposed for the pathophysiology of high BP even as its prevalence continues to grow worldwide, increasing morbidity and marking it as a major public health concern. To address this, we evaluated miRNA profiling in blood leukocytes as potential biomarkers of BP and BP-related risk factors. Methods The Beijing Truck Driver Air Pollution Study included 60 truck drivers and 60 office workers examined in 2008. On two days separated by 1–2 weeks, we examined three BP measures: systolic, diastolic, and mean arterial pressure measured at both pre- and post-work exams for blood NanoString nCounter miRNA profiles. We used covariate-adjusted linear mixed-effect models to examine associations between BP and increased miRNA expression in both pooled and risk factor-stratified analyses. Results Overall 43 miRNAs were associated with pre-work BP (FDR<0.05). In stratified analyses different but overlapping groups of miRNAs were associated with pre-work BP in truck drivers, high-BMI participants, and usual alcohol drinkers (FDR<0.05). Only four miRNAs were associated with post-work BP (FDR<0.05), in ever smokers. Conclusion Our results suggest that many miRNAs were significantly associated with BP in subgroups exposed to known hypertension risk factors. These findings shed light on the underlying molecular mechanisms of BP, and may assist with the development of a miRNA panel for early detection of hypertension. PMID:28278198

  1. Blood pressure and expression of microRNAs in whole blood.

    PubMed

    Zhang, Zhou; Joyce, Brian Thomas; Kresovich, Jacob K; Zheng, Yinan; Zhong, Jia; Patel, Ruchi; Zhang, Wei; Liu, Lei; Dou, Chang; McCracken, John P; Díaz, Anaité; Motta, Valeria; Sanchez-Guerra, Marco; Bian, Shurui; Bertazzi, Pier Alberto; Schwartz, Joel; Baccarelli, Andrea A; Wang, Sheng; Hou, Lifang

    2017-01-01

    Blood pressure (BP) is a complex, multifactorial clinical outcome driven by genetic susceptibility, behavioral choices, and environmental factors. Many molecular mechanisms have been proposed for the pathophysiology of high BP even as its prevalence continues to grow worldwide, increasing morbidity and marking it as a major public health concern. To address this, we evaluated miRNA profiling in blood leukocytes as potential biomarkers of BP and BP-related risk factors. The Beijing Truck Driver Air Pollution Study included 60 truck drivers and 60 office workers examined in 2008. On two days separated by 1-2 weeks, we examined three BP measures: systolic, diastolic, and mean arterial pressure measured at both pre- and post-work exams for blood NanoString nCounter miRNA profiles. We used covariate-adjusted linear mixed-effect models to examine associations between BP and increased miRNA expression in both pooled and risk factor-stratified analyses. Overall 43 miRNAs were associated with pre-work BP (FDR<0.05). In stratified analyses different but overlapping groups of miRNAs were associated with pre-work BP in truck drivers, high-BMI participants, and usual alcohol drinkers (FDR<0.05). Only four miRNAs were associated with post-work BP (FDR<0.05), in ever smokers. Our results suggest that many miRNAs were significantly associated with BP in subgroups exposed to known hypertension risk factors. These findings shed light on the underlying molecular mechanisms of BP, and may assist with the development of a miRNA panel for early detection of hypertension.

  2. Realization of wide size range 1D ZnO micro/nano rods for versatile micro/nano devices by controlled seed layer thickness

    NASA Astrophysics Data System (ADS)

    Sun, Jingchang; Bian, Jiming; Chen, Liansong; Wang, Yuxin; Gong, Yu; Li, Yang; Liu, Kuichao; Chang, Cheng; Li, Ming; Du, Guotong

    2013-07-01

    We report on the effect of seed layers thickness on the synthesis of one dimensional (1D) ZnO rods using chemical bath deposition method. This procedure allows us to control the length and diameter of 1D ZnO rods in a large size range by modifying the ZnO seed layer thickness. With the increase in thickness of the seed layer, the length of the 1D ZnO rods ranges from 13.1 μm to 2.1 μm, and the diameter varies from 2.4 μm to 102 nm, meanwhile the laying 1D ZnO rods standup gradually. Photoluminescence measurements indicate that the near band edge emission of the 1D ZnO rods blueshift to higher energy direction with the increasing seed layers thickness.

  3. The potential for climate-driven bathymetric range shifts: sustained temperature and pressure exposures on a marine ectotherm, Palaemonetes varians

    PubMed Central

    Morris, J. P.; Thatje, S.; Cottin, D.; Oliphant, A.; Brown, A.; Shillito, B.; Ravaux, J.; Hauton, C.

    2015-01-01

    Range shifts are of great importance as a response for species facing climate change. In the light of current ocean-surface warming, many studies have focused on the capacity of marine ectotherms to shift their ranges latitudinally. Bathymetric range shifts offer an important alternative, and may be the sole option for species already at high latitudes or those within enclosed seas; yet relevant data are scant. Hydrostatic pressure (HP) and temperature have wide ranging effects on physiology, importantly acting in synergy thermodynamically, and therefore represent key environmental constraints to bathymetric migration. We present data on transcriptional regulation in a shallow-water marine crustacean (Palaemonetes varians) at atmospheric and high HP following 168-h exposures at three temperatures across the organisms’ thermal scope, to establish the potential physiological limit to bathymetric migration by neritic fauna. We observe changes in gene expression indicative of cellular macromolecular damage, disturbances in metabolic pathways and a lack of acclimation after prolonged exposure to high HP. Importantly, these effects are ameliorated (less deleterious) at higher temperatures, and exacerbated at lower temperatures. These data, alongside previously published behavioural and heat-shock analyses, have important implications for our understanding of the potential for climate-driven bathymetric range shifts PMID:26716003

  4. The potential for climate-driven bathymetric range shifts: sustained temperature and pressure exposures on a marine ectotherm, Palaemonetes varians.

    PubMed

    Morris, J P; Thatje, S; Cottin, D; Oliphant, A; Brown, A; Shillito, B; Ravaux, J; Hauton, C

    2015-11-01

    Range shifts are of great importance as a response for species facing climate change. In the light of current ocean-surface warming, many studies have focused on the capacity of marine ectotherms to shift their ranges latitudinally. Bathymetric range shifts offer an important alternative, and may be the sole option for species already at high latitudes or those within enclosed seas; yet relevant data are scant. Hydrostatic pressure (HP) and temperature have wide ranging effects on physiology, importantly acting in synergy thermodynamically, and therefore represent key environmental constraints to bathymetric migration. We present data on transcriptional regulation in a shallow-water marine crustacean (Palaemonetes varians) at atmospheric and high HP following 168-h exposures at three temperatures across the organisms' thermal scope, to establish the potential physiological limit to bathymetric migration by neritic fauna. We observe changes in gene expression indicative of cellular macromolecular damage, disturbances in metabolic pathways and a lack of acclimation after prolonged exposure to high HP. Importantly, these effects are ameliorated (less deleterious) at higher temperatures, and exacerbated at lower temperatures. These data, alongside previously published behavioural and heat-shock analyses, have important implications for our understanding of the potential for climate-driven bathymetric range shifts.

  5. Active flow control of subsonic flow in an adverse pressure gradient using synthetic jets and passive micro flow control devices

    NASA Astrophysics Data System (ADS)

    Denn, Michael E.

    Several recent studies have shown the advantages of active and/or passive flow control devices for boundary layer flow modification. Many current and future proposed air vehicles have very short or offset diffusers in order to save vehicle weight and create more optimal vehicle/engine integration. Such short coupled diffusers generally result in boundary layer separation and loss of pressure recovery which reduces engine performance and in some cases may cause engine stall. Deployment of flow control devices can alleviate this problem to a large extent; however, almost all active flow control devices have some energy penalty associated with their inclusion. One potential low penalty approach for enhancing the diffuser performance is to combine the passive flow control elements such as micro-ramps with active flow control devices such as synthetic jets to achieve higher control authority. The goal of this dissertation is twofold. The first objective is to assess the ability of CFD with URANS turbulence models to accurately capture the effects of the synthetic jets and micro-ramps on boundary layer flow. This is accomplished by performing numerical simulations replicating several experimental test cases conducted at Georgia Institute of Technology under the NASA funded Inlet Flow Control and Prediction Technologies Program, and comparing the simulation results with experimental data. The second objective is to run an expanded CFD matrix of numerical simulations by varying various geometric and other flow control parameters of micro-ramps and synthetic jets to determine how passive and active control devices interact with each other in increasing and/or decreasing the control authority and determine their influence on modification of boundary layer flow. The boundary layer shape factor is used as a figure of merit for determining the boundary layer flow quality/modification and its tendency towards separation. It is found by a large number of numerical experiments and

  6. The study of pressure measurement techniques and devices in the range of 10(exp -1) to 10(exp -5) torr (2 millipsi to 0.2 micropsi)

    NASA Technical Reports Server (NTRS)

    Hoffman, John H.

    1990-01-01

    The atmospheric pressure range was studied in a region where conventional pressure sensing devices do not provide meaningful measurements. However, a hot filament gauge was developed and miniaturized which will measure the pressure in the 10(exp -1) to 10(exp -5) torr (2 millipsi to 0.2 micropsi) region, hence the name Micropsi gauge. Laboratory studies were made comparing the currently available devices with the newly developed miniature low power 'Micropsi' pressure sensor.

  7. Multiphase Binary Mixture Flows in Porous Media in a Wide Pressure and Temperature Range Including Critical Conditions

    NASA Astrophysics Data System (ADS)

    Afanasyev, A.

    2011-12-01

    Multiphase flows in porous media with a transition between sub- and supercritical thermodynamic conditions occur in many natural and technological processes (e.g. in deep regions of geothermal reservoirs where temperature reaches critical point of water or in gas-condensate fields where subject to critical conditions retrograde condensation occurs and even in underground carbon dioxide sequestration processes at high formation pressure). Simulation of these processes is complicated due to degeneration of conservation laws under critical conditions and requires non-classical mathematical models and methods. A new mathematical model is proposed for efficient simulation of binary mixture flows in a wide range of pressures and temperatures that includes critical conditions. The distinctive feature of the model lies in the methodology for mixture properties determination. Transport equations and Darcy law are solved together with calculation of the entropy maximum that is reached in thermodynamic equilibrium and determines mixture composition. To define and solve the problem only one function - mixture thermodynamic potential - is required. Such approach allows determination not only single-phase states and two-phase states of liquid-gas type as in classical models but also two-phase states of liquid-liquid type and three-phase states. The proposed mixture model was implemented in MUFITS (Multiphase Filtration Transport Simulator) code for hydrodynamic simulations. As opposed to classical approaches pressure, enthalpy and composition variables together with fully implicit method and cascade procedure are used. The code is capable of unstructured grids, heterogeneous porous media, relative permeability and capillary pressure dependence on temperature and pressure, multiphase diffusion, optional number of sink and sources, etc. There is an additional module for mixture properties specification. The starting point for the simulation is a cubic equation of state that is

  8. Pressure dependent stability and structure of carbon dioxide—A density functional study including long-range corrections

    NASA Astrophysics Data System (ADS)

    Gohr, Sebastian; Grimme, Stefan; Söhnel, Tilo; Paulus, Beate; Schwerdtfeger, Peter

    2013-11-01

    First-principles density functional theory (DFT) is used to study the solid-state modifications of carbon dioxide up to pressures of 60 GPa. All known molecular CO2 structures are investigated in this pressure range, as well as three non-molecular modifications. To account for long-range van der Waals interactions, the dispersion corrected DFT method developed by Grimme and co-workers (DFT-D3) is applied. We find that the DFT-D3 method substantially improves the results compared to the uncorrected DFT methods for the molecular carbon dioxide crystals. Enthalpies at 0 K and cohesive energies support only one possibility of the available experimental solutions for the structure of phase IV: the Roverline{3}c modification, proposed by Datchi and co-workers [Phys. Rev. Lett. 103, 185701 (2009)]. Furthermore, comparing bulk moduli with experimental values, we cannot reproduce the quite large—rather typical for covalent crystal structures—experimental values for the molecular phases II and III.

  9. Transient radon signals driven by fluid pressure pulse, micro-crack closure, and failure during granite deformation experiments

    NASA Astrophysics Data System (ADS)

    Girault, Frédéric; Schubnel, Alexandre; Pili, Éric

    2017-09-01

    In seismically active fault zones, various crustal fluids including gases are released at the surface. Radon-222, a radioactive gas naturally produced in rocks, is used in volcanic and tectonic contexts to illuminate crustal deformation or earthquake mechanisms. At some locations, intriguing radon signals have been recorded before, during, or after tectonic events, but such observations remain controversial, mainly because physical characterization of potential radon anomalies from the upper crust is lacking. Here we conducted several month-long deformation experiments under controlled dry upper crustal conditions with a triaxial cell to continuously monitor radon emission from crustal rocks affected by three main effects: a fluid pressure pulse, micro-crack closure, and differential stress increase to macroscopic failure. We found that these effects are systematically associated with a variety of radon signals that can be explained using a first-order advective model of radon transport. First, connection to a source of deep fluid pressure (a fluid pressure pulse) is associated with a large transient radon emission increase (factor of 3-7) compared with the background level. We reason that peak amplitude is governed by the accumulation time and the radon source term, and that peak duration is controlled by radioactive decay, permeability, and advective losses of radon. Second, increasing isostatic compression is first accompanied by an increase in radon emission followed by a decrease beyond a critical pressure representing the depth below which crack closure hampers radon emission (150-250 MPa, ca. 5.5-9.5 km depth in our experiments). Third, the increase of differential stress, and associated shear and volumetric deformation, systematically triggers significant radon peaks (ca. 25-350% above background level) before macroscopic failure, by connecting isolated cracks, which dramatically enhances permeability. The detection of transient radon signals before rupture

  10. Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications

    PubMed Central

    Su, Shujing; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

    2017-01-01

    The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa. PMID:28841168

  11. Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

    PubMed

    Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

    2017-08-25

    The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

  12. A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes

    SciTech Connect

    Eckels, S.J.; Doerr, T.M.; Pate, M.B.

    1998-10-01

    The average heat transfer coefficients and pressure drops during evaporation and condensation are reported for mixtures of R-134a and an ester lubricant in tubes of 12.7 mm (1/2 in.) outer diameter. The objective of this paper is to evaluate the performance of the R-134a-lubricant mixtures in these tubes and determine the performance benefits of the micro-fin tube. The performance benefits of the tubes with 12.7 mm (1/2 in.) outer diameter are compared to those of smaller tubes with 9.52 mm (3/8 in.) outer diameter. The lubricant used was a 169 SUS penta erythritol ester mixed-acid lubricant. The lubricant concentration was varied from 0--5.1% in the mixture. The average heat transfer coefficients in the 12.7 mm (1/2 in.) micro-fin tube were 50--150% higher than those for the 12.7 mm (1/2 in.) smooth tube, while pressure drops in the micro-fin tube were 5% to 50% higher than in the smooth tube. The addition of lubricant degraded the average heat transfer coefficients in all cases except during evaporation at low lubricant concentrations. Pressure drops were always increased with the addition of lubricant. The experimental results also indicate that tube diameter has some effect on the performance benefits of the micro-fin tube over that of the smooth tube.

  13. An analysis of experimental data and prediction methods for two-phase frictional pressure drop and flow boiling heat transfer in micro-scale channels

    SciTech Connect

    Ribatski, Gherhardt; Wojtan, Leszek; Thome, John R.

    2006-10-15

    Experimental results for two-phase frictional pressure drop and flow boiling heat transfer in micro-scale channels were obtained from the literature. The extensive pressure drop database comprises both diabatic and adiabatic results covering eight fluids, mass velocities from 23 to 6000kg/m{sup 2}s and vapor qualities up to 1. These data were carefully analyzed and compared against 12 two-phase frictional pressure drop prediction methods, including both macro- and micro-scale methods. Overall, the methods by Muller-Steinhagen and Heck and by Mishima and Hibiki, as well as the homogenous model, using the two-phase viscosity definition proposed by Cicchitti and coworkers, provide the most accurate predictions. However, they worked poorly at vapor qualities higher than 0.5 where annular, partial dryout and mist flow patterns would be expected. Similarly, a large database for micro-scale flow boiling heat transfer for eleven fluids covering mass velocities from 100 to 800kg/m{sup 2}s, reduced pressures from 0.03 to 0.77 and heat fluxes from 5 to 180kW/m{sup 2} were compared against three recently proposed micro-scale and one well-known macro-scale heat transfer prediction method. Although some heat transfer trends were captured by the methods, in general they poorly predicted the database. This is not surprising since an analysis of the trends of the experimental results revealed large discrepancies between different data sets, even at similar experimental conditions, and no present method could capture such contrasting trends. The study concludes that the 3-zone model proposed by Thome and coworkers based on the transient conduction through an evaporating liquid film seems to be the most promising approach to predict heat transfer coefficients in micro-scale channels but is still not sufficiently developed to use as a general design tool. (author)

  14. Phase-Contrast Micro-Computed Tomography Measurements of the Intraocular Pressure-Induced Deformation of the Porcine Lamina Cribrosa.

    PubMed

    Coudrillier, Baptiste; Geraldes, Diogo M; Vo, Nghia T; Atwood, Robert; Reinhard, Christina; Campbell, Ian C; Raji, Yazdan; Albon, Julie; Abel, Richard L; Ethier, C Ross

    2016-04-01

    The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, high-resolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC μCT) at IOPs between 6 and 37 mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 μm. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive devformation within the LC, with maximum tensile strains at 30 mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC μCT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.

  15. Phase-contrast Micro-computed Tomography Measurements of the Intraocular Pressure-induced Deformation of the Porcine Lamina Cribrosa.

    PubMed

    Coudrillier, Baptiste; Geraldes, Diogo; Vo, Nghia; Atwood, Robert; Reinhard, Christina; Campbell, Ian; Raji, Yazdan; Albon, Julie; Abel, Richard; Ethier, Ross

    2015-11-30

    The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, highresolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC CT) at IOPs between 6 and 37mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 m. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive deformation within the LC, with maximum tensile strains at 30mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC CT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.

  16. Long-range micro-pulse aerosol lidar at 1.5  μm with an upconversion single-photon detector.

    PubMed

    Xia, Haiyun; Shentu, Guoliang; Shangguan, Mingjia; Xia, Xiuxiu; Jia, Xiaodong; Wang, Chong; Zhang, Jun; Pelc, Jason S; Fejer, M M; Zhang, Qiang; Dou, Xiankang; Pan, Jian-Wei

    2015-04-01

    A micro-pulse lidar at eye-safe wavelength is constructed based on an upconversion single-photon detector. The ultralow-noise detector enables using integration technique to improve the signal-to-noise ratio of the atmospheric backscattering even at daytime. With pulse energy of 110 μJ, pulse repetition rate of 15 kHz, optical antenna diameter of 100 mm and integration time of 5 min, a horizontal detection range of 7 km is realized. In the demonstration experiment, atmospheric visibility over 24 h is monitored continuously, with results in accordance with the weather forecasts.

  17. Experimental investigation of the Cu/R141b nanofluids on the evaporation/boiling heat transfer characteristics for surface with capillary micro-channels

    NASA Astrophysics Data System (ADS)

    Diao, Yanhua; Liu, Yan; Wang, Rui; Zhao, Yaohua; Guo, Lei

    2014-09-01

    An experimental study was conducted to investigate the heat transfer characteristic of a vertical copper plate with rectangular micro-channels. In this research, Cu/R141b nanofluids were used as the working fluid. Three different volume concentrations—0.001, 0.01, and 0.1 %—of Cu nanoparticles with an average diameter of 20 nm dispersed in R141b were prepared. Experiments were performed to measure thermal resistance of the microchannel surface under a steady operating pressure range of 0.86 × 105 Pa to 2 × 105 Pa. Thermal resistance weakened with addition of nanoparticles into the base fluid. The maximum reduction effect of the thermal resistance was 50 %, which corresponds to 0.01 % volume concentration of nanofluid at low operating pressure. The operating pressure significantly affects thermal performance of the microchannel surface. This paper also studied heat transfer characteristics for a Cu nanoparticle-coated surface with rectangular microchannels, which were produced by heating in different volume concentrations from 0.001 to 0.1 %. Nanoparticle layer on the micro-channel surface is responsible for enhanced heat transfer of nanofluids with 0.001 and 0.01 % volume concentrations.

  18. Pressure and shear stress in trabecular bone marrow during whole bone loading.

    PubMed

    Metzger, Thomas A; Schwaner, Stephen A; LaNeve, Anthony J; Kreipke, Tyler C; Niebur, Glen L

    2015-09-18

    Skeletal adaptation to mechanical loading is controlled by mechanobiological signaling. Osteocytes are highly responsive to applied strains, and are the key mechanosensory cells in bone. However, many cells residing in the marrow also respond to mechanical cues such as hydrostatic pressure and shear stress, and hence could play a role in skeletal adaptation. Trabecular bone encapsulates marrow, forming a poroelastic solid. According to the mechanical theory, deformation of the pores induces motion in the fluid-like marrow, resulting in pressure and velocity gradients. The latter results in shear stress acting between the components of the marrow. To characterize the mechanical environment of trabecular bone marrow in situ, pore pressure within the trabecular compartment of whole porcine femurs was measured with miniature pressure transducers during stress-relaxation and cyclic loading. Pressure gradients ranging from 0.013 to 0.46 kPa/mm were measured during loading. This range was consistent with calculated pressure gradients from continuum scale poroelastic models with the same permeability. Micro-scale computational fluid dynamics models created from computed tomography images were used to calculate the micromechanical stress in the marrow using the measured pressure differentials as boundary conditions. The volume averaged shear stress in the marrow ranged from 1.67 to 24.55 Pa during cyclic loading, which exceeds the mechanostimulatory threshold for mesenchymal lineage cells. Thus, the loading of bone through activities of daily living may be an essential component of bone marrow health and mechanobiology. Additional studies of cell-level interactions during loading in healthy and disease conditions will provide further incite into marrow mechanobiology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Microfluidic pressure sensing using trapped air compression.

    PubMed

    Srivastava, Nimisha; Burns, Mark A

    2007-05-01

    We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid-air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d approximately 50 microm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700-100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions.

  20. Microfluidic pressure sensing using trapped air compression

    PubMed Central

    Srivastava, Nimisha; Burns, Mark A.

    2010-01-01

    We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid–air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d ~ 50 μm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700–100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions. PMID:17476384

  1. Factors influencing the echocardiographic estimate of right ventricular systolic pressure in normal patients and clinically relevant ranges according to age.

    PubMed

    Armstrong, David W J; Tsimiklis, Georgios; Matangi, Murray F

    2010-02-01

    Previous studies have shown that in the absence of underlying cardiac pathology, the echocardiographic estimate of right ventricular systolic pressure (RVSP) increases progressively and normally with age. There are limited data in patients older than 60 years of age. To define the ranges of RVSP according to age and to include more elderly patients than have previously been reported. All patients undergoing echocardiography since May 26, 1999, at the Kingston Heart Clinic (Kingston, Ontario) have had their data entered into a locally designed cardiology database (CARDIOfile; Registered trademark, Kingston Heart Clinic). RVSP was calculated from the peak tricuspid regurgitant jet velocity (V) using the modified Bernoulli equation (RVSP = 4V2 + RAP), with the mean right atrial pressure (RAP) estimated to be 10 mmHg. Of the 22,628 patients who had undergone echocardiography, 10,905 had RVSP measured. All abnormal echocardiograms were excluded, leaving 1559 echocardiograms for analysis. Patient age ranged from 15 to 93 years. The mean age was 49 years. RVSP increased significantly only after the age of 50 years. The mean (+/- SD) RVSP for those younger than 50 years, 50 to 75 years, and older than 75 years of age was 27.3+/-5.7 mmHg, 30.2+/-7.6 mmHg and 34.8+/-8.7 mmHg, respectively (P<0.0001 among all age groups). The normal range (95% CI) of RVSP in those younger than 50 years, 50 to 75 years, and older than 75 years of age was 16 mmHg to 39 mmHg, 15 mmHg to 45 mmHg, and 17 mmHg to 52 mmHg, respectively. Multivariate analysis indicated that age, mitral diastolic early-to-late filling velocity ratio, ejection fraction, aortic size and early mitral filling velocity/ early diastolic mitral annular velocity were the only significant independent variables. There were significant changes in diastolic function with increasing age, which may have been responsible for the changes in RVSP. RVSP remains stable in both men and women until the age of 50 years. Thereafter, RVSP

  2. Near infrared excited micro-Raman spectra of 4:1 methanol-ethanol mixture and ruby fluorescence at high pressure

    NASA Astrophysics Data System (ADS)

    Wang, X. B.; Shen, Z. X.; Tang, S. H.; Kuok, M. H.

    1999-06-01

    Near infrared (NIR) lasers, as a new excitation source for Raman spectroscopy, has shown its unique advantages and is being increasingly used for some special samples, such as those emitting strong fluorescence in the visible region. This article focuses on some issues related to high-pressure micro-Raman spectroscopy using NIR excitation source. The Raman spectra of 4:1 methanol-ethanol mixture (4:1 M-E) show a linear variation in both Raman shifts and linewidths under pressure up to 18 GPa. This result is useful in distinguishing Raman scattering of samples from that of the alcohol mixture, an extensively used pressure-transmitting medium. The R1 fluorescence in the red region induced by two-photon absorption of the NIR laser is strong enough to be used as pressure scale. The frequency and line width of the R1 lines are very sensitive to pressure change and the glass transition of the pressure medium. Our results manifest that it is reliable and convenient to use NIR induced two-photon excited fluorescence of ruby for both pressure calibration and distribution of pressure in the 4:1 M-E pressure transmitting medium.

  3. MicroRNA-328 inhibits renal tubular cell epithelial-to-mesenchymal transition by targeting the CD44 in pressure-induced renal fibrosis.

    PubMed

    Chen, Cheng-Hsien; Cheng, Chung-Yi; Chen, Yen-Cheng; Sue, Yuh-Mou; Liu, Chung-Te; Cheng, Tzu-Hurng; Hsu, Yung-Ho; Chen, Tso-Hsiao

    2014-01-01

    Epithelial-mesenchymal transition (EMT) occurs in stressed tubular epithelial cells, contributing to renal fibrosis. Initial mechanisms promoting EMT are unknown. Pressure force is an important mechanism contributing to the induction and progression of renal fibrogenesis in ureteric obstruction. In our study of cultured rat renal tubular cells (NRK-52E) under 60 mmHg of pressure, we found that the epithelial marker E-cadherin decreased and mesenchymal markers, e.g., α-smooth muscle actin, fibronectin and Snail, increased. Pressure also induced the expression of connective tissue growth factor and transforming growth factor-β. MicroRNA array assays showed that pressure reduced miR-328 at the initial stage of pressurization. We identified a potential target sequence of miR-328 in rat CD44 3'-untranslated regions. In contrast with the miR-328 expression, CD44 expression was up-regulated at the initial pressurization stage. We also found that miR-328 expression decreased and CD44 increased in ureteric obstruction kidneys in the animal study. CD44 siRNA transfection significantly increased E-cadherin expression and inhibited pressure-induced EMT. Both hyaluronan binding peptide pep-1 and osteopontin neutralizing antibody inhibited pressure-induced EMT. Our results suggest that miR-328-mediated CD44 transient upregulation is an important trigger of the pressure-induced EMT in renal fibrosis.

  4. 3D strain measurement in soft tissue: demonstration of a novel inverse finite element model algorithm on MicroCT images of a tissue phantom exposed to negative pressure wound therapy.

    PubMed

    Wilkes, R; Zhao, Y; Cunningham, K; Kieswetter, K; Haridas, B

    2009-07-01

    This study describes a novel system for acquiring the 3D strain field in soft tissue at sub-millimeter spatial resolution during negative pressure wound therapy (NPWT). Recent research in advanced wound treatment modalities theorizes that microdeformations induced by the application of sub-atmospheric (negative) pressure through V.A.C. GranuFoam Dressing, a reticulated open-cell polyurethane foam (ROCF), is instrumental in regulating the mechanobiology of granulation tissue formation [Saxena, V., Hwang, C.W., Huang, S., Eichbaum, Q., Ingber, D., Orgill, D.P., 2004. Vacuum-assisted closure: Microdeformations of wounds and cell proliferation. Plast. Reconstr. Surg. 114, 1086-1096]. While the clinical response is unequivocal, measurement of deformations at the wound-dressing interface has not been possible due to the inaccessibility of the wound tissue beneath the sealed dressing. Here we describe the development of a bench-test wound model for microcomputed tomography (microCT) imaging of deformation induced by NPWT and an algorithm set for quantifying the 3D strain field at sub-millimeter resolution. Microdeformations induced in the tissue phantom revealed average tensile strains of 18%-23% at sub-atmospheric pressures of -50 to -200 mmHg (-6.7 to -26.7 kPa). The compressive strains (22%-24%) and shear strains (20%-23%) correlate with 2D FEM studies of microdeformational wound therapy in the reference cited above. We anticipate that strain signals quantified using this system can then be used in future research aimed at correlating the effects of mechanical loading on the phenotypic expression of dermal fibroblasts in acute and chronic ulcer models. Furthermore, the method developed here can be applied to continuum deformation analysis in other contexts, such as 3D cell culture via confocal microscopy, full scale CT and MRI imaging, and in machine vision.

  5. Using Range-Wide Abundance Modeling to Identify Key Conservation Areas for the Micro-Endemic Bolson Tortoise (Gopherus flavomarginatus)

    PubMed Central

    Ureña-Aranda, Cinthya A.; Rojas-Soto, Octavio; Martínez-Meyer, Enrique; Yáñez-Arenas, Carlos; Landgrave Ramírez, Rosario; Espinosa de los Monteros, Alejandro

    2015-01-01

    A widespread biogeographic pattern in nature is that population abundance is not uniform across the geographic range of species: most occurrence sites have relatively low numbers, whereas a few places contain orders of magnitude more individuals. The Bolson tortoise Gopherus flavomarginatus is endemic to a small region of the Chihuahuan Desert in Mexico, where habitat deterioration threatens this species with extinction. In this study we combined field burrows counts and the approach for modeling species abundance based on calculating the distance to the niche centroid to obtain range-wide abundance estimates. For the Bolson tortoise, we found a robust, negative relationship between observed burrows abundance and distance to the niche centroid, with a predictive capacity of 71%. Based on these results we identified four priority areas for the conservation of this microendemic and threatened tortoise. We conclude that this approach may be a useful approximation for identifying key areas for sampling and conservation efforts in elusive and rare species. PMID:26115482

  6. Using Range-Wide Abundance Modeling to Identify Key Conservation Areas for the Micro-Endemic Bolson Tortoise (Gopherus flavomarginatus).

    PubMed

    Ureña-Aranda, Cinthya A; Rojas-Soto, Octavio; Martínez-Meyer, Enrique; Yáñez-Arenas, Carlos; Landgrave Ramírez, Rosario; Espinosa de los Monteros, Alejandro

    2015-01-01

    A widespread biogeographic pattern in nature is that population abundance is not uniform across the geographic range of species: most occurrence sites have relatively low numbers, whereas a few places contain orders of magnitude more individuals. The Bolson tortoise Gopherus flavomarginatus is endemic to a small region of the Chihuahuan Desert in Mexico, where habitat deterioration threatens this species with extinction. In this study we combined field burrows counts and the approach for modeling species abundance based on calculating the distance to the niche centroid to obtain range-wide abundance estimates. For the Bolson tortoise, we found a robust, negative relationship between observed burrows abundance and distance to the niche centroid, with a predictive capacity of 71%. Based on these results we identified four priority areas for the conservation of this microendemic and threatened tortoise. We conclude that this approach may be a useful approximation for identifying key areas for sampling and conservation efforts in elusive and rare species.

  7. Optimal frequency ranges for extracting information on cardiovascular autonomic control from the blood pressure and pulse interval spectrograms in mice.

    PubMed

    Baudrie, Véronique; Laude, Dominique; Elghozi, Jean-Luc

    2007-02-01

    The analysis of blood pressure (BP) and heart rate (HR) variability by spectral methods has proven a useful tool in many animal species for the assessment of the vagal and sympathetic contributions to oscillations of BP and HR. Continuous BP measurements obtained in mice by telemetry were used to characterize the spectral bandwidths of autonomic relevance by using an approach with no a priori. The paradigm was based on the autonomic blockades obtained with conventional drugs (atropine, prazosin, atenolol). The spectral changes were estimated in all of the combinations of spectral bandwidths. The effect of hydralazine was also tested using the same systematic analysis, to detect the zones of sympathetic activation resulting reflexly from the vasodilatory action of the drug. Two zones of interest in the study of the autonomic control of BP and HR were observed. The first zone covered the 0.15-0.60 Hz range of the systolic BP spectrum and corresponds to the low-frequency zone (or Mayer waves). This zone reflects sympathetic control since the power spectral density of this zone was significantly reduced with alpha1-adrenoceptor blockade (prazosin), while it was significantly amplified as a result of a reflex sympathetic activation (hydralazine). The second zone covered the 2.5-5.0 Hz range of the pulse interval spectrum and corresponded to the high-frequency zone (respiratory sinus arrhythmia) under vagal control (blocked by atropine). These zones are recommended for testing the autonomic control of circulation in mice.

  8. Friction force of smooth surfaces of SiO 2-SiO 2 as a function of residual pressure

    NASA Astrophysics Data System (ADS)

    Deulin, E. A.; Gatsenko, A. A.; Loginov, B. A.

    1999-08-01

    Experiments were carried out to study aspects of the dry friction of 'smooth' surfaces of silicon monocrystal wafers covered with SiO 2 over a wide range of residual pressure from 10 5 to 10 -8 Pa. The experiments show that a plot of the dynamic friction coefficient, fd, versus residual pressure, P, for smooth surfaces is more complex than the same for 'traditional' surfaces and confirm the existence of four ranges of pressure with different behavior of fd in each: (1) surface tension, (2) quasi-viscous, (3) adhesive and (4) cohesive friction. The behavior of fd in the pressure range P=10 -2-10 -9 Pa ensures the basis of the criterion of the extremely high vacuum (EHV) formulation. The friction coefficient fd decreases with pressure in the ultrahigh vacuum (UHV) range P=10 -2-10 -7 Pa and increases in the pressure range P<10 -7 Pa (UHV).

  9. USING LIGA BASED MICROFABRICATION TO IMPROVE OVERALL HEAT TRANSFER EFFICIENCY OF PRESSURIZED WATER REACTOR: I. Effects of Different Micro Pattern on Overall Heat Transfer.

    SciTech Connect

    Zhang, M.; Ibekwe, S.; Li, G.; Pang, S.S.; and Lian, K.

    2006-07-01

    The Pressurized Water Reactors (PWRs in Figure 1) were originally developed for naval propulsion purposes, and then adapted to land-based applications. It has three parts: the reactor coolant system, the steam generator and the condenser. The Steam generator (a yellow area in Figure 1) is a shell and tube heat exchanger with high-pressure primary water passing through the tube side and lower pressure secondary feed water as well as steam passing through the shell side. Therefore, a key issue in increasing the efficiency of heat exchanger is to improve the design of steam generator, which is directly translated into economic benefits. The past research works show that the presence of a pin-fin array in a channel enhances the heat transfer significantly. Hence, using microfabrication techniques, such as LIGA, micro-molding or electroplating, some special microstructures can be fabricated around the tubes in the heat exchanger to increase the heat-exchanging efficiency and reduce the overall size of the heat-exchanger for the given heat transfer rates. In this paper, micro-pin fins of different densities made of SU-8 photoresist are fabricated and studied to evaluate overall heat transfer efficiency. The results show that there is an optimized micro pin-fin configuration that has the best overall heat transfer effects.

  10. Efficacy and Safety of Continuous Micro-Pump Infusion of 3% Hypertonic Saline combined with Furosemide to Control Elevated Intracranial Pressure

    PubMed Central

    Li, Yuqian; Li, Zhihong; Li, Min; Yang, Yanlong; Wang, Bao; Gao, Li; Zhang, Xingye; Cheng, Hongyu; Fang, Wei; Zhao, Bo; Wang, Boliang; Gao, Guodong; Li, Lihong

    2015-01-01

    Background Elevated intracranial pressure is one of the most common problems in patients with diverse intracranial disorders, leading to increased morbidity and mortality. Effective management for increased intracranial pressure is based mainly on surgical and medical techniques with hyperosmolar therapy as one of the core medical treatments. The study aimed to explore the effects of continuous micro-pump infusions of 3% hypertonic saline combined with furosemide on intracranial pressure control. Material/Methods We analyzed data on 56 eligible participants with intracranial pressure >20 mmHg from March 2013 to July 2014. The target was to increase and maintain plasma sodium to a level between 145 and 155 mmol/L and osmolarity to a level of 310 to 320 mOsmol/kg. Results Plasma sodium levels significantly increased from 138±5 mmol/L at admission to 151±3 mmol/L at 24 h (P<0.01). Osmolarity increased from 282±11 mOsmol/kg at baseline to 311±8 mOsmol/kg at 24 h (P<0.01). Intracranial pressure significantly decreased from 32±7 mmHg to 15±6 mmHg at 24 h (P<0.01). There was a significant improvement in CPP (P<0.01). Moreover, central venous pressure, mean arterial pressure, and Glasgow Coma Scale slightly increased. However, these changes were not statistically significant. Conclusions Continuous infusion of 3% hypertonic saline + furosemide is effective and safe for intracranial pressure control. PMID:26082293

  11. Digital Holographic Interferometry of a Wide Spectral Range in the Systems of Nondestructive Testing of Dynamics of Micro- and Macrosystems

    NASA Astrophysics Data System (ADS)

    Alekseenko, I. V.; Gusev, M. E.

    2015-01-01

    Modern digital holographic interferometry is used to study the objects of various nature and various spatial scales. In this case, a wide spectral range of coherent electromagnetic radiation from long-wavelength infrared to deep ultraviolet is used. In this work, we present the results of studying dynamic processes in construction materials by the methods of digital holographic interferometry using radiation with a wavelength of up to 9.3 μm. The holographic method for testing of microelectromechanical structures is also considered. The method of digital holographic interferometry, which uses an automated holographic microscope, is proposed to study microscopic biological objects.

  12. Record tuning range of a 1.55 {micro}m DBR laser realized by selective area growth

    SciTech Connect

    Delprat, D.; Silvestre, L.; Ougazzaden, A.; Delorme, F.; Slempkes, S.; Ramdane, A.

    1996-12-31

    A DBR laser diode with a record 7 nm tuning range has been demonstrated using SAG. The use of MQW structures combined with a small detuning between active and tuning regions of the device have lead to an appreciable output power stability while tuning it. SAG appears as a very simple way for achieving wavelength compatibility. This demonstrates the potential of the method to realize with strained InGaAsP/InGaAsP MQW more complex components with for example three sections of different transition energy.

  13. Sound pressure level variations across the Pacific based on IMS data

    NASA Astrophysics Data System (ADS)

    Yamada, Tomoaki; Haralabus, Georgios; Zampolli, Mario; Heaney, Kevin

    2017-04-01

    Low frequency hydro-acoustic waves can be detected at great distances due to low attenuation of acoustic energy in the SOund Fixing And Ranging (SOFAR) channel. These waves contain both acoustic source and propagation medium information which is difficult to separate at the receiving end. This study examines sound pressure level variations across the pacific using 100 underwater controlled sources near a landward slope zone in Japan to minimize source uncertainty. The data were acquired at water-column hydrophones of the hydroacoustic station HA03 at Chile that is part of the International Monitoring System (IMS) of the Comprehensive Nuclear Test Ban Treaty. Acoustics waves were detected over 15,000 km across the Pacific and initial analysis indicates a maximum difference of the pressure level is 17 dB re. micro Pa.

  14. Performance analysis and design optimization of micro-jet impingement heat sink

    NASA Astrophysics Data System (ADS)

    Husain, Afzal; Kim, Sun-Min; Kim, Kwang-Yong

    2013-11-01

    This study evaluated a silicon-based micro-jet impingement heat sink for electronic cooling applications. First, the pressure-drop and thermal characteristics were investigated for steady incompressible and laminar flow by solving three-dimensional Navier-Stokes equations, and the performance enhancement was carried out through parametric and optimization studies. Several parallel and staggered micro-jet configurations consisting of a maximum of 16 jet impingements were tested. The effectiveness of the micro-jet configurations, i.e. inline 2 × 2, 3 × 3 and 4 × 4 jets, and staggered 5-jet and 13-jet arrays with nozzle diameters 50, 76, and 100 μm, were analyzed at various flow rates for the maximum temperature-rise and pressure-drop characteristics. A design with a staggered 13-jet array showed the best performance among the various configurations investigated in the present study. The design optimization based on three-dimensional numerical analysis, surrogate modeling and a multi-objective evolutionary algorithm were carried out to understand the thermal resistance and pumping power correlation of the micro-jet impingement heat sink. Two design variables, the ratio of height of the channel and nozzle diameter, and the ratio of nozzle diameter and interjet spacing, were chosen for design optimization. The global Pareto-optimal front was achieved for overall thermal resistance and required pumping power of the heat sink. The Pareto-optimal front revealed existing correlation between pumping power and thermal resistance of the heat sink. Of the range of Pareto-optimal designs available, some representative designs were selected and their functional relationships among the objective functions and design variables were examined to understand the Pareto-optimal sensitivity and optimal design space. A minimum of 66 °C of maximum-temperature-rise was obtained for a heat flux of 100 W/cm2 at a pressure drop of about 24 kPa.

  15. Graphene-Paper Pressure Sensor for Detecting Human Motions.

    PubMed

    Tao, Lu-Qi; Zhang, Kun-Ning; Tian, He; Liu, Ying; Wang, Dan-Yang; Chen, Yuan-Quan; Yang, Yi; Ren, Tian-Ling

    2017-09-26

    Pressure sensors should have an excellent sensitivity in the range of 0-20 kPa when applied in wearable applications. Traditional pressure sensors cannot achieve both a high sensitivity and a large working range simultaneously, which results in their limited applications in wearable fields. There is an urgent need to develop a pressure sensor to make a breakthrough in both sensitivity and working range. In this paper, a graphene-paper pressure sensor that shows excellent performance in the range of 0-20 kPa is proposed. Compared to most reported graphene pressure sensors, this work realizes the optimization of sensitivity and working range, which is especially suitable for wearable applications. We also demonstrate that the pressure sensor can be applied in pulse detection, respiratory detection, voice recognition, as well as various intense motion detections. This graphene-paper pressure sensor will have great potentials for smart wearable devices to achieve health monitoring and motion detection.

  16. Nanopositioning and nanomeasuring machine NPMM-200—a new powerful tool for large-range micro- and nanotechnology

    NASA Astrophysics Data System (ADS)

    Jäger, G.; Manske, E.; Hausotte, T.; Müller, A.; Balzer, F.

    2016-09-01

    High-precision metrology has emerged as an enabling technology for modern key technologies. Therefore, at the Technische Universität Ilmenau, a new nanopositioning and nanomeasuring machine NPMM-200 with a measuring range of 200 mm × 200 mm × 25 mm, and a resolution of 0.02 nm was developed. The machine represents the great improvement of the extended three-dimensional Abbe comparator principle to achieve nanometre accuracy. All six degrees of freedom of the mirror plate with the measuring object are measured by fibre-coupled laser interferometers, the signals of which are then used together with the probe system signals for a high-precision position and orientation control and surface and coordinate measurements. This paper presents the metrological concept, the realized design as well as the metrological parameters.

  17. High-pressure potato starch granule gelatinization: synchrotron radiation micro-SAXS/WAXS using a diamond anvil cell.

    PubMed

    Gebhardt, R; Hanfland, M; Mezouar, M; Riekel, C

    2007-07-01

    Potato starch granules have been examined by synchrotron radiation small- and wide-angle scattering in a diamond anvil cell (DAC) up to 750 MPa. Use of a 1 microm synchrotron radiation beam allowed the mapping of individual granules at several pressure levels. The data collected at 183 MPa show an increase in the a axis and lamellar period from the edge to the center of the granule, probably due to a gradient in water content of the crystalline and amorphous lamellae. The average granules radius increases up to the onset of gelatinization at about 500 MPa, but the a axis and the lamellar periodicity remain constant or even show a decrease, suggesting an initial hydration of amorphous growth rings. The onset of gelatinization is accompanied by (i) an increase in the average a axis and lamellar periodicity, (ii) the appearance of an equatorial SAXS streak, and (iii) additional short-range order peaks.

  18. Narrow-line external cavity diode laser micro-packaging in the NIR and MIR spectral range

    NASA Astrophysics Data System (ADS)

    Jiménez, A.; Milde, T.; Staacke, N.; Aßmann, C.; Carpintero, G.; Sacher, J.

    2017-07-01

    Narrow-linewidth tunable diode lasers are an important tool for spectroscopic instrumentation. Conventional external cavity diode lasers offer high output power and narrow linewidth. However, most external cavity diode lasers are designed as laboratory instrument and do not allow portability. In comparison, other commonly used lasers, like distributed feedback lasers (DFB) that are capable of driving a handheld device, are limited in power and show linewidths which are not sufficiently narrow for certain applications. We present new miniaturized types of tunable external cavity diode laser which overcome the drawbacks of conventional external cavity diode lasers and which preserve the advantages of this laser concept. Three different configurations are discussed in this article. The three types of miniaturized external cavity diode laser systems achieve power values of more than 50 mW within the 1.4 μm water vapor absorption band with excellent side-mode suppression and linewidth below 100 kHz. Typical features outstand with respect to other type of laser systems which are of extended use such as DFB laser diodes. The higher output power and the lower linewidth will enable a higher sensitivity and resolution for a wide range of applications.

  19. Short range shooting distance estimation using variable pressure SEM images of the surroundings of bullet holes in textiles.

    PubMed

    Hinrichs, Ruth; Frank, Paulo Ricardo Ost; Vasconcellos, M A Z

    2017-03-01

    Modifications of cotton and polyester textiles due to shots fired at short range were analyzed with a variable pressure scanning electron microscope (VP-SEM). Different mechanisms of fiber rupture as a function of fiber type and shooting distance were detected, namely fusing, melting, scorching, and mechanical breakage. To estimate the firing distance, the approximately exponential decay of GSR coverage as a function of radial distance from the entrance hole was determined from image analysis, instead of relying on chemical analysis with EDX, which is problematic in the VP-SEM. A set of backscattered electron images, with sufficient magnification to discriminate micrometer wide GSR particles, was acquired at different radial distances from the entrance hole. The atomic number contrast between the GSR particles and the organic fibers allowed to find a robust procedure to segment the micrographs into binary images, in which the white pixel count was attributed to GSR coverage. The decrease of the white pixel count followed an exponential decay, and it was found that the reciprocal of the decay constant, obtained from the least-square fitting of the coverage data, showed a linear dependence on the shooting distance.

  20. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

    SciTech Connect

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

    2015-07-15

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  1. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

    NASA Astrophysics Data System (ADS)

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

    2015-07-01

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  2. The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team.

    PubMed

    Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

    2015-07-01

    We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

  3. Pressure-driven mesofluidic platform integrating automated on-chip renewable micro-solid-phase extraction for ultrasensitive determination of waterborne inorganic mercury.

    PubMed

    Portugal, Lindomar A; Laglera, Luis M; Anthemidis, Aristidis N; Ferreira, Sérgio L C; Miró, Manuel

    2013-06-15

    A dedicated pressure-driven mesofluidic platform incorporating on-chip sample clean-up and analyte preconcentration is herein reported for expedient determination of trace level concentrations of waterborne inorganic mercury. Capitalizing upon the Lab-on-a-Valve (LOV) concept, the mesofluidic device integrates on-chip micro-solid phase extraction (μSPE) in automatic disposable mode followed by chemical vapor generation and gas-liquid separation prior to in-line atomic fluorescence spectrometric detection. In contrast to prevailing chelating sorbents for Hg(II), bare poly(divinylbenzene-N-vinylpyrrolidone) copolymer sorptive beads were resorted to efficient uptake of Hg(II) in hydrochloric acid milieu (pH=2.3) without the need for metal derivatization nor pH adjustment of prior acidified water samples for preservation to near-neutral conditions. Experimental variables influencing the sorptive uptake and retrieval of target species and the evolvement of elemental mercury within the miniaturized integrated reaction chamber/gas-liquid separator were investigated in detail. Using merely <10 mg of sorbent, the limits of detection and quantification at the 3s(blank) and 10s(blank) levels, respectively, for a sample volume of 3 mL were 12 and 42 ng L(-1) Hg(II) with a dynamic range extending up to 5.0 μg L(-1). The proposed mesofluidic platform copes with the requirements of regulatory bodies (US-EPA, WHO, EU-Commission) for drinking water quality and surface waters that endorse maximum allowed concentrations of mercury spanning from 0.07 to 6.0 μg L(-1). Demonstrated with the analysis of aqueous samples of varying matrix complexity, the LOV approach afforded reliable results with relative recoveries of 86-107% and intermediate precision down to 9% in the renewable μSPE format. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Development of a high temperature capacitive pressure transducer

    NASA Technical Reports Server (NTRS)

    Egger, R. L.

    1977-01-01

    High temperature pressure transducers capable of continuous operation while exposed to 650 C were developed and evaluated over a full-scale differential pressure range of + or - 69 kPa. The design of the pressure transducers was based on the use of a diaphragm to respond to pressure, variable capacitive elements arranged to operate as a differential capacitor to measure diaphragm response and on the use of fused silica for the diaphragm and its supporting assembly. The uncertainty associated with measuring + or - 69 kPa pressures between 20C and 650C was less than + or - 6%.

  5. Interactions Between Small Arrays of Atmospheric Pressure Micro-Plasma Jets: Gas Dynamic, Radiation and Electrostatic Interactions

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia

    2013-09-01

    Atmospheric pressure plasma jets are widely used devices for biomedical applications. A typical plasma jet consists of a tube through which noble gas or its mixture with a molecular gas flows. The noble gas creates a channel into the ambient air which is eventually dispersed by interdiffusion with the air. Plasma plumes are formed by the propagation of ionization waves (IWs) through the tubes and then through the noble gas phase channel. The IW typically propagates until the mole fraction of the ambient air in the channel increases above a critical values which requires a larger E/N to propagate the IW. By grouping several jets together to form an array of jets, one can in principle increase the area treated by the plume. If the jets are sufficiently far apart, the IWs and resulting plasma plumes are independent. As the spacing between the jets decreases, the plasma jets begin to mutually interact. In this talk, we discuss results from a computational investigation of small arrays of He/O2 micro-plasma jets propagating into ambient air. The model used in this work, nonPDPSIM, is a plasma hydrodynamics model in which continuity, momentum and energy equations are solved for charged and neutral species with solution of Poisson's equation for the electric potential. Navier-Stokes equations are solved for the gas dynamics and radiation transport is addressed using a propagator method. We found that as the spacing between the jets decreases, the He channels from the individual jets tend to merge. The IWs from each channel also merge into regions having the highest He mole fraction and so lowest E/N to sustain the IW. The proximity of the IWs enable other forms of interaction. If the IWs are of the same polarity, electrostatic forces can warp the paths of the IWs. If in sufficient proximity, the photoionization from one IW can influence its neighbors. The synchronization of the voltage pulses of adjacent IWs can also influence its neighbors. With synchronized pulses

  6. Vascular mineralocorticoid receptor regulates microRNA-155 to promote vasoconstriction and rising blood pressure with aging

    PubMed Central

    DuPont, Jennifer J.; McCurley, Amy; Davel, Ana P.; McCarthy, Joseph; Bender, Shawn B.; Hong, Kwangseok; Yang, Yan; Yoo, Jeung-Ki; Aronovitz, Mark; Baur, Wendy E.; Christou, Demetra D.; Hill, Michael A.; Jaffe, Iris Z.

    2016-01-01

    Hypertension is nearly universal yet poorly controlled in the elderly despite proven benefits of intensive treatment. Mice lacking mineralocorticoid receptors in smooth muscle cells (SMC-MR-KO) are protected from rising blood pressure (BP) with aging, despite normal renal function. Vasoconstriction is attenuated in aged SMC-MR-KO mice, thus they were used to explore vascular mechanisms that may contribute to hypertension with aging. MicroRNA (miR) profiling identified miR-155 as the most down-regulated miR with vascular aging in MR-intact but not SMC-MR-KO mice. The aging-associated decrease in miR-155 in mesenteric resistance vessels was associated with increased mRNA abundance of MR and of predicted miR-155 targets Cav1.2 (L-type calcium channel (LTCC) subunit) and angiotensin type-1 receptor (AgtR1). SMC-MR-KO mice lacked these aging-associated vascular gene expression changes. In HEK293 cells, MR repressed miR-155 promoter activity. In cultured SMCs, miR-155 decreased Cav1.2 and AgtR1 mRNA. Compared to MR-intact littermates, aged SMC-MR-KO mice had decreased systolic BP, myogenic tone, SMC LTCC current, mesenteric vessel calcium influx, LTCC-induced vasoconstriction and angiotensin II-induced vasoconstriction and oxidative stress. Restoration of miR-155 specifically in SMCs of aged MR-intact mice decreased Cav1.2 and AgtR1 mRNA and attenuated LTCC-mediated and angiotensin II-induced vasoconstriction and oxidative stress. Finally, in a trial of MR blockade in elderly humans, changes in serum miR-155 predicted the BP treatment response. Thus, SMC-MR regulation of miR-155, Cav1.2 and AgtR1 impacts vasoconstriction with aging. This novel mechanism identifies potential new treatment strategies and biomarkers to improve and individualize antihypertensive therapy in the elderly. PMID:27683672

  7. Effect of PaCO2 and PaO2 on lidocaine and articaine toxicity.

    PubMed

    Barcelos, K C; Furtado, D P; Ramacciato, J C; Cabral, A M; Haas, D A

    2010-01-01

    Alterations in arterial PaCO₂ can influence local anesthetic toxicity. The objective of this study was to evaluate the effect of stress-induced changes in PaCO₂ and PaO₂ on the seizure threshold of lidocaine and articaine. Lidocaine (2% with 1 : 100,000 epinephrine) or articaine (4% with 1 : 100,000 epinephrine) was administered intravenously under rest or stress conditions to 36 rats separated into 4 groups. Propranolol and prazosin were administered preoperatively to minimize cardiovascular effects of epinephrine. Mean arterial pressure (MAP), heart rate (HR), and arterial pH, PaCO₂, and PaO₂ were measured. Results showed no differences in MAP, HR, or pH. Stress significantly increased the latency period for the first tonic-clonic seizure induced by a toxic dose of both lidocaine and articaine (P < .05). Seizures were brought on more rapidly by articaine. No significant difference between toxic doses of lidocaine and articaine was noted. Stress raised the seizure threshold dose for both drugs and significantly (P < .01) increased arterial PaO₂ from 94.0 ± 1.90 mm Hg to 113.0 ± 2.20 mm Hg, and reduced PaCO₂ from 36.0 ± 0.77 mm Hg to 27.0 ± 0.98 mm Hg. In conclusion, reduction in PaCO₂ and/or increase in PaO₂ raised the seizure threshold of lidocaine and articaine. This study also confirmed that lidocaine and articaine have equipotent central nervous system toxicity.

  8. Effect of PaCO2 and PaO2 on Lidocaine and Articaine Toxicity

    PubMed Central

    Barcelos, K.C; Furtado, D.P; Ramacciato, J.C; Cabral, A.M; Haas, D.A

    2010-01-01

    Alterations in arterial PaCO2 can influence local anesthetic toxicity. The objective of this study was to evaluate the effect of stress-induced changes in PaCO2 and PaO2 on the seizure threshold of lidocaine and articaine. Lidocaine (2% with 1 ∶ 100,000 epinephrine) or articaine (4% with 1 ∶ 100,000 epinephrine) was administered intravenously under rest or stress conditions to 36 rats separated into 4 groups. Propranolol and prazosin were administered preoperatively to minimize cardiovascular effects of epinephrine. Mean arterial pressure (MAP), heart rate (HR), and arterial pH, PaCO2, and PaO2 were measured. Results showed no differences in MAP, HR, or pH. Stress significantly increased the latency period for the first tonic-clonic seizure induced by a toxic dose of both lidocaine and articaine (P < .05). Seizures were brought on more rapidly by articaine. No significant difference between toxic doses of lidocaine and articaine was noted. Stress raised the seizure threshold dose for both drugs and significantly (P < .01) increased arterial PaO2 from 94.0 ± 1.90 mm Hg to 113.0 ± 2.20 mm Hg, and reduced PaCO2 from 36.0 ± 0.77 mm Hg to 27.0 ± 0.98 mm Hg. In conclusion, reduction in PaCO2 and/or increase in PaO2 raised the seizure threshold of lidocaine and articaine. This study also confirmed that lidocaine and articaine have equipotent central nervous system toxicity. PMID:20843225

  9. An accuracy statement for a facility used to calibrate static pressure transducers and differential pressure transducers at high base pressure

    NASA Astrophysics Data System (ADS)

    Sindt, C. F.; Labrecque, J. F.

    1982-06-01

    A facility was developed to calibrate pressure transducers that are used in a gas mass flow facility. Both static and differential pressure transducers can be calibrated. An air dead weight tester is the standard for static transducers in the range from 3.8 to 4.5 MPa. An air dead weight tester is also the standard for the differential pressure transducers in the range of 2.5 kPa to 50 MPa; a cistern manometer. This, plus the uncertainties in the high pressure corrections to the cistern manometer and measurement of the mercury temperature, contributes plus or minus 690 ppm to the uncertainty of the differential pressure transducer calibrations.

  10. A photonic wall pressure sensor for fluid mechanics applications.

    PubMed

    Manzo, M; Ioppolo, T; Ayaz, U K; Lapenna, V; Ötügen, M V

    2012-10-01

    In this paper, we demonstrate a micro-optical wall pressure sensor concept based on the optical modes of dielectric resonators. The sensing element is a spherical micro-resonator with a diameter of a few hundred micrometers. A latex membrane that is flush mounted on the wall transmits the normal pressure to the sensing element. Changes in the wall pressure perturb the sphere's morphology, leading to a shift in the optical modes. The wall pressure is measured by monitoring the shifts in the optical modes. Prototype sensors with polydimethylsiloxane micro-spheres are tested in a steady two-dimensional channel flow and in a plane wave acoustic tube. Results indicate sensor resolutions of ∼20 mPa and bandwidth of up to 2 kHz.

  11. Dynamic behaviour of a planar micro-beam loaded by a fluid-gap: Analytical and numerical approach in a high frequency range, benchmark solutions

    NASA Astrophysics Data System (ADS)

    Novak, A.; Honzik, P.; Bruneau, M.

    2017-08-01

    Miniaturized vibrating MEMS devices, active (receivers or emitters) or passive devices, and their use for either new applications (hearing, meta-materials, consumer devices,…) or metrological purposes under non-standard conditions, are involved today in several acoustic domains. More in-depth characterisation than the classical ones available until now are needed. In this context, the paper presents analytical and numerical approaches for describing the behaviour of three kinds of planar micro-beams of rectangular shape (suspended rigid or clamped elastic planar beam) loaded by a backing cavity or a fluid-gap, surrounded by very thin slits, and excited by an incident acoustic field. The analytical approach accounts for the coupling between the vibrating structure and the acoustic field in the backing cavity, the thermal and viscous diffusion processes in the boundary layers in the slits and the cavity, the modal behaviour for the vibrating structure, and the non-uniformity of the acoustic field in the backing cavity which is modelled in using an integral formulation with a suitable Green's function. Benchmark solutions are proposed in terms of beam motion (from which the sensitivity, input impedance, and pressure transfer function can be calculated). A numerical implementation (FEM) is handled against which the analytical results are tested.

  12. Density measurements of subcooled water in the temperature range of (243 and 283) K and for pressures up to 400 MPa.

    PubMed

    Romeo, Raffaella; Giuliano Albo, P Alberto; Lorefice, Salvatore; Lago, Simona

    2016-02-21

    In this work, accurate density measurements of subcooled water (freshly double-distilled water) were performed along eight constant-mass curves in the temperature range of (243 to 283) K and in the pressure range of (140 to 400) MPa, by a pseudo-isochoric method. The experimental apparatus mainly consisted of a high pressure vessel, especially designed for this experiment, of known volume as a function of temperature and pressure, used to perform measurements in the T-p range under study. The density of subcooled water was obtained by measuring the equilibrium pressure at different temperatures, keeping the mass constant. All terms contributing to the uncertainty of subcooled water density measurements were considered; the estimated relative uncertainty, in the investigated temperature and pressure range, is about 0.07%. The experimental results were compared with the literature densities. In particular, the trend of density versus temperature for a constant mass of sample observed experimentally differs from the trend calculated by the equation provided by the International Association for Properties of Water and Steam (IAPWS-95) outside the range of validity, i.e., in the metastable region.

  13. Skin debris and micro-organisms on the periwound skin of pressure ulcers and the influence of periwound cleansing on microbial flora.

    PubMed

    Konya, Chizuko; Sanada, Hiromi; Sugama, Junko; Kitayama, Yukie; Ishikawa, Shinji; Togashi, Hiroyasu; Tamura, Shigeru

    2005-01-01

    Many clinicians use the same solution, most often normal saline, to cleanse the periwound skin and the wound bed itself. However, skin debris such as water-insoluble proteins and lipids are not efficiently removed by normal saline solutions. To analyze the skin debris and micro-organisms found on the periwound skin of pressure ulcers and to evaluate the effect of periwound cleansing on the microbial flora, a descriptive study was conducted among 17 long-term care residents with Stage III and IV pressure ulcers. Skin debris from both the periwound area and normal skin was collected from all 17 residents. In addition, micro-organisms from the wound bed, periwound, and normal skin of five residents were collected before, immediately after, and 6 hours and 24 hours after periwound cleansing using a skin cleanser. All microbial species were identified by cultivation. Cholesterol and nitrogen-containing substances were found in greater quantity on the periwound than on normal skin (P = 0.0027 and P = 0.0054, respectively) and the number of isolated micro-organisms from the periwound area was larger than that from normal skin. Protein showed the highest correlation to the microbial count present on the periwound (r = 0.71, P = 0.0014). The microbial counts of all isolated micro-organisms decreased immediately after cleansing but the number of isolates with high microbial counts increased over time. In the wound bed, the number of isolates with decreasing microbial counts was larger than the number of isolates with increasing microbial counts. Both numbers returned to pre-cleansing values after 24 hours, suggesting that periwound cleansing only (without directly cleansing the wound bed) is effective at reducing the microbial counts in the wound bed for up to 24 hours. Further research is needed to evaluate the effects of periwound cleansing on healing time.

  14. {sup 231}Pa photofission cross section

    SciTech Connect

    Soldatov, A.S.; Rudnikov, V.E.; Smirenkin, G.N.

    1995-12-01

    The measurements of the {sup 231}Pa yield and cross section photofission in the energy range 7-9 MeV are presented. These measurements are a continuation of similar measurements performed for the {gamma}-ray energy range 4.8-7 MeV. The entire collection of experimental data which combine the results obtained in the present work and in Ref. 1 was analyzed.

  15. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  16. Heteronuclear Micro-Helmholtz Coil Facilitates µm-Range Spatial and Sub-Hz Spectral Resolution NMR of nL-Volume Samples on Customisable Microfluidic Chips

    PubMed Central

    Spengler, Nils; Höfflin, Jens; Moazenzadeh, Ali; Mager, Dario; MacKinnon, Neil; Badilita, Vlad; Wallrabe, Ulrike; Korvink, Jan G.

    2016-01-01

    We present a completely revised generation of a modular micro-NMR detector, featuring an active sample volume of ∼ 100 nL, and an improvement of 87% in probe efficiency. The detector is capable of rapidly screening different samples using exchangeable, application-specific, MEMS-fabricated, microfluidic sample containers. In contrast to our previous design, the sample holder chips can be simply sealed with adhesive tape, with excellent adhesion due to the smooth surfaces surrounding the fluidic ports, and so withstand pressures of ∼2.5 bar, while simultaneously enabling high spectral resolution up to 0.62 Hz for H2O, due to its optimised geometry. We have additionally reworked the coil design and fabrication processes, replacing liquid photoresists by dry film stock, whose final thickness does not depend on accurate volume dispensing or precise levelling during curing. We further introduced mechanical alignment structures to avoid time-intensive optical alignment of the chip stacks during assembly, while we exchanged the laser-cut, PMMA spacers by diced glass spacers, which are not susceptible to melting during cutting. Doing so led to an overall simplification of the entire fabrication chain, while simultaneously increasing the yield, due to an improved uniformity of thickness of the individual layers, and in addition, due to more accurate vertical positioning of the wirebonded coils, now delimited by a post base plateau. We demonstrate the capability of the design by acquiring a 1H spectrum of ∼ 11 nmol sucrose dissolved in D2O, where we achieved a linewidth of 1.25 Hz for the TSP reference peak. Chemical shift imaging experiments were further recorded from voxel volumes of only ∼ 1.5nL, which corresponded to amounts of just 1.5 nmol per voxel for a 1 M concentration. To extend the micro-detector to other nuclei of interest, we have implemented a trap circuit, enabling heteronuclear spectroscopy, demonstrated by two 1H/13C 2D HSQC experiments. PMID

  17. Heteronuclear Micro-Helmholtz Coil Facilitates µm-Range Spatial and Sub-Hz Spectral Resolution NMR of nL-Volume Samples on Customisable Microfluidic Chips.

    PubMed

    Spengler, Nils; Höfflin, Jens; Moazenzadeh, Ali; Mager, Dario; MacKinnon, Neil; Badilita, Vlad; Wallrabe, Ulrike; Korvink, Jan G

    2016-01-01

    We present a completely revised generation of a modular micro-NMR detector, featuring an active sample volume of ∼ 100 nL, and an improvement of 87% in probe efficiency. The detector is capable of rapidly screening different samples using exchangeable, application-specific, MEMS-fabricated, microfluidic sample containers. In contrast to our previous design, the sample holder chips can be simply sealed with adhesive tape, with excellent adhesion due to the smooth surfaces surrounding the fluidic ports, and so withstand pressures of ∼2.5 bar, while simultaneously enabling high spectral resolution up to 0.62 Hz for H2O, due to its optimised geometry. We have additionally reworked the coil design and fabrication processes, replacing liquid photoresists by dry film stock, whose final thickness does not depend on accurate volume dispensing or precise levelling during curing. We further introduced mechanical alignment structures to avoid time-intensive optical alignment of the chip stacks during assembly, while we exchanged the laser-cut, PMMA spacers by diced glass spacers, which are not susceptible to melting during cutting. Doing so led to an overall simplification of the entire fabrication chain, while simultaneously increasing the yield, due to an improved uniformity of thickness of the individual layers, and in addition, due to more accurate vertical positioning of the wirebonded coils, now delimited by a post base plateau. We demonstrate the capability of the design by acquiring a 1H spectrum of ∼ 11 nmol sucrose dissolved in D2O, where we achieved a linewidth of 1.25 Hz for the TSP reference peak. Chemical shift imaging experiments were further recorded from voxel volumes of only ∼ 1.5 nL, which corresponded to amounts of just 1.5 nmol per voxel for a 1 M concentration. To extend the micro-detector to other nuclei of interest, we have implemented a trap circuit, enabling heteronuclear spectroscopy, demonstrated by two 1H/13C 2D HSQC experiments.

  18. Precise tumor size measurement under constant pressure by novel real-time micro-electro-mechanical-system hood for proper treatment (with videos).

    PubMed

    Mori, Hirohito; Takao, Hidekuni; Kobara, Hideki; Nishiyama, Noriko; Fujihara, Shintaro; Matsunaga, Tae; Ayaki, Maki; Masaki, Tsutomu

    2015-01-01

    Tumor size determination is subject to the measurement method used by endoscopists and is especially dependent on the air quantity. As the intraluminal pressure must be measured objectively to obtain an accurate tumor size measurement, insufflation can affect the results. Thus, we examined the utility of a micro-electro-mechanical-system (MEMS) pressure sensor hood. Twenty consecutive air insufflation/deflation tests were performed in vivo using a dog's stomach. Correlations between the actual pressure measured and the signal strength of the MEMS hood were measured. We marked 2 points 20 mm on the antrum and another 3 points, with insufflation corresponding to the maximum stable distance of two markings. We performed five insufflation/deflation tests to obtain the relationship between pressure and distances to accurately measure the distance under constant pressure. In the air insufflation/deflation test performed 20 consecutive times, the MEMS hood signal strength (V) and the pressure measurement sensor values (mmHg) showed good correlation. There was good correlation between intraluminal pressures of 2.5-40 mmHg and the two marking distances on the antrum (correlation coefficient 0.952) (P < 0.05). However, once the intraluminal pressure reached a certain level (40 mmHg), expansion of the two marking distances ceased. The same measurements were conducted on the greater curvatures of the lower body and middle body and on the lesser curvature of the lower body. Correct tumor size measurements using a MEMS hood enable a more accurate diagnosis, which can be used to develop suitable treatment strategies.

  19. Suprathermal electron energy spectrum and nonlocally affected plasma-wall interaction in helium/air micro-plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.

    2016-10-01

    Details of ground-state and excited-state neutral atoms and molecules in an atmospheric-pressure micro-discharge plasma may be obtained by plasma electron spectroscopy (PLES), based on a wall probe. The presence and transport of energetic (suprathermal) electrons, having a nonlocal origin, are responsible for electrostatic charging of the plasma boundary surfaces to potentials many times that associated with the ambient electron kinetic energy. The energy-flux distribution function is shown to be controllable for applications involving analysis of composition and processes taking place in a multiphase (plasma-gas-solid), chemically reactive, interaction region.

  20. Diamond-anvil cell observations of a new methane hydrate phase in the 100-MPa pressure range

    USGS Publications Warehouse

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2001-01-01

    A new high-pressure phase of methane hydrate has been identified based on its high optical relief, distinct pressure-temperature phase relations, and Raman spectra. In-situ optical observations were made in a hydrothermal diamond-anvil cell at temperatures between -40?? and 60 ??C and at pressures up to 900 MPa. Two new invariant points were located at -8.7 ??C and 99 MPa for the assemblage consisting of the new phase, structure I methane hydrate, ice Ih, and water, and at 35.3 ??C and 137 MPa for the new phase-structure I methane hydrate-water-methane vapor. Existence of the new phase is critical for understanding the phase relations among the hydrates at low to moderate pressures, and may also have important implications for understanding the hydrogen bonding in H2O and the behavior of water in the planetary bodies, such as Europa, of the outer solar system.

  1. Effect of Water Vapor Pressure on Fatigue Crack Growth in Al-Zn-Cu-Mg Alloy Over Wide-Range Stress Intensity Factor Loading

    DTIC Science & Technology

    2014-05-07

    Lee United States Air Force Academy Title: Effect of Water Vapor Pressure on Fatigue Crack Growth in Al-Zn-Cu- Mg Alloy Over Wide-range Stress...Al- li-Cu- Mg alloys in vacuum, Metall Trans A, 24 (1993) 1807-1817. [46] R.D. Carter, E.W. Lee, E.A. Starke, C.J. Beevers, The Effect of...Vapor Pressure on Fatigue Crack Growth in Al-Zn-Cu- Mg Alloy Over Wide-range Stress Intensity Factor Loading J.T. Bums1, R.W. Bush2, J. Ai1, J.L Jones1

  2. Survival of fossilised diatoms and forams in hypervelocity impacts with peak shock pressures in the 1-19 GPa range

    NASA Astrophysics Data System (ADS)

    Burchell, M. J.; Harriss, K. H.; Price, M. C.; Yolland, L.

    2017-07-01

    Previously it has been shown that diatom fossils embedded in ice could survive impacts at speeds of up to 5 km s-1 and peak shock pressures up to 12 GPa. Here we confirm these results using a different technique, with diatoms carried in liquid water suspensions at impact speeds of 2-6 km s-1. These correspond to peak shock pressures of 3.8-19.8 GPa. We also report on the results of similar experiments using forams, at impact speeds of 4.67 km s-1 (when carried in water) and 4.73 km s-1 (when carried in ice), corresponding to peak shock pressures of 11.6 and 13.1 GPa respectively. In all cases we again find survival of recognisable fragments, with mean fragment size of order 20-25 μm. We compare our results to the peak shock pressures that ejecta from giant impacts on the Earth would experience if it subsequently impacted the Moon. We find that 98% of impacts of terrestrial ejecta on the Moon would have experienced peak pressures less than 20 GPa if the ejecta were a soft rock (sandstone). This falls to 82% of meteorites if the ejecta were a hard rock (granite). This assumes impacts on a solid lunar surface. If we approximate the surface as a loose regolith, over 99% of the impacts involve peak shock pressures below 20 GPa. Either way, the results show that a significant fraction of terrestrial meteorites impacting the Moon will do so with peak shock pressures which in our experiments permit the survival of recognisable fossil fragments.

  3. On-line Analysis of Catalytic Reaction Products Using a High-Pressure Tandem Micro-reactor GC/MS.

    PubMed

    Watanabe, Atsushi; Kim, Young-Min; Hosaka, Akihiko; Watanabe, Chuichi; Teramae, Norio; Ohtani, Hajime; Kim, Seungdo; Park, Young-Kwon; Wang, Kaige; Freeman, Robert R

    2017-01-01

    When a GC/MS system is coupled with a pressurized reactor, the separation efficiency and the retention time are directly affected by the reactor pressure. To keep the GC column flow rate constant irrespective of the reaction pressure, a restrictor capillary tube and an open split interface are attached between the GC injection port and the head of a GC separation column. The capability of the attached modules is demonstrated for the on-line GC/MS analysis of catalytic reaction products of a bio-oil model sample (guaiacol), produced under a pressure of 1 to 3 MPa.

  4. Optical pressure sensor based on the combined system of a variable liquid lens and a point diffraction interferometer.

    PubMed

    García, Anmi; Gómez, Manuel; Acosta, Eva

    2012-03-01

    We propose an experimental efficient optical pressure sensor based on a variable liquid lens and a modified point diffraction interferometer. The working principle of the sensor is based on the fact that a variation in pressure induces a change in lens curvature and hence in its focal length, which can be tracked and measured with the interferometer. The pressure is then measured by recording and processing the interferometric images. The sensor in this proposal can change its dynamic range by the simple axial movement of one of the components of the optical system. In this work we show the performance of the system within three working ranges: from 0 to 1 kPa with accuracy of approximately 0.01 kPa, from 0 to 7 kPa with 0.05 kPa accuracy, and from 0 to 30 kPa with 0.3 kPa accuracy. © 2012 Optical Society of America

  5. Kinetic study on the photoabsorption process of gaseous O 2 dimol at 630 nm in a wide pressure range

    NASA Astrophysics Data System (ADS)

    Ida, Akira; Furui, Eiji; Akai, Nobuyuki; Kawai, Akio; Shibuya, Kazuhiko

    2010-03-01

    The visible light absorption of gaseous O 2 dimol at 630 nm was measured in the pressure region of 0.04-90 atm. The intensities measured at high pressures did not agree with the values extrapolated from the data obtained at low pressures. A kinetic analysis assuming the equilibrium between the dimol and free O 2 monomers was performed. All the data are well reproduced by the model using the 630 nm absorption cross-section of (5.6 ± 3.3) × 10 -24 cm 2 molecule -1 and the dissociation equilibrium constant of (6.8 ± 4.2) × 10 21 molecules cm -3. The critical distance between the O 2 molecules in the dimol is discussed on the basis of the equilibrium constant determined.

  6. Highly pressurized partially miscible liquid-liquid flow in a micro-T-junction. I. Experimental observations

    NASA Astrophysics Data System (ADS)

    Qin, Ning; Wen, John Z.; Ren, Carolyn L.

    2017-04-01

    This is the first part of a two-part study on a partially miscible liquid-liquid flow (liquid carbon dioxide and deionized water) which is highly pressurized and confined in a microfluidic T-junction. Our main focuses are to understand the flow regimes as a result of varying flow conditions and investigate the characteristics of drop flow distinct from coflow, with a capillary number, C ac , that is calculated based on the continuous liquid, ranging from 10-3 to 10-2 (10-4 for coflow). Here in part I, we present our experimental observation of drop formation cycle by tracking drop length, spacing, frequency, and after-generation speed using high-speed video and image analysis. The drop flow is chronologically composed of a stagnating and filling stage, an elongating and squeezing stage, and a truncating stage. The common "necking" time during the elongating and squeezing stage (with C ac˜10-3 ) for the truncation of the dispersed liquid stream is extended, and the truncation point is subsequently shifted downstream from the T-junction corner. This temporal postponement effect modifies the scaling function reported in the literature for droplet formation with two immiscible fluids. Our experimental measurements also demonstrate the drop speed immediately following their generations can be approximated by the mean velocity from averaging the total flow rate over the channel cross section. Further justifications of the quantitative analysis by considering the mass transfer at the interface of the two partially miscible fluids are provided in part II.

  7. A micro-liter viscosity and density sensor for the rheological characterization of DNA solutions in the kilo-hertz range.

    PubMed

    Rust, Philipp; Cereghetti, Damiano; Dual, Jurg

    2013-12-21

    When measuring the properties of fluids from biological sources, sample volumes in the micro-liter range are often desired as higher volumes may not be available or are very expensive. Miniaturized viscosity and density sensors based on a vibrating cantilever fulfill this requirement. In this paper, the possibility of measuring viscosity and density of DNA solutions at the same time using such a sensor is shown. The sensor requires a sample volume of 10 μl. By doing a titration of a solution containing 110 bp long strands of DNA in the diluted, Newtonian regime, the intrinsic viscosity can be determined to be 0.047 ml mg(-1) using the cantilever sensor. The cantilever is also tested with solutions of 10 kbp long strands with concentrations in the semi-dilute, non-Newtonian regime. The comparably small change in resonance frequency and damping observed using these solutions at 12.5 kHz is attributed to shear thinning, which is expected when extrapolating results from other groups.

  8. Blast Pressures Induced by the Impact of Kinetic Energy Penetrators on Steel Targets in an Enclosed Range.

    DTIC Science & Technology

    1981-02-01

    heat of detonation of pentolite is Sl k.J/g, so the kinetic energy of the tungsten penetrators is equal to the heat of detonation of...the heat of detonation of pentolite, 5.11 kJ/g. Then the scaled distance curves 3 can be used to predict blast pressure at the instrumented position for...kinetic and chemical energy is 11.8 MJ which equals the heat of detonation of 2.3 kg of pentolite. This would produce a reflected blast pressure of

  9. Simultaneous and in situ analysis of thermal and volumetric properties of starch gelatinization over wide pressure and temperature ranges.

    PubMed

    Randzio, Stanislaw L; Orlowska, Marta

    2005-01-01

    A method for simultaneous and in situ analysis of thermal and volumetric properties of starch gelatinization from 0.1 to 100 MPa and from 283 to 430 K is described. The temperature of a very sensitive calorimetric detector containing a starch-water emulsion at a selected pressure is programmed to rise at a slow rate; volume variations are performed automatically to keep the selected pressure constant while the heat exchange rate and the volume are recorded. The method is demonstrated with a novel investigation of pressure effects on a sequence of three phase transitions in an aqueous emulsion of wheat starch (56 wt % water). The volume changes during the main endothermic transition (M), associated with melting of the crystalline part of the starch granules and a helix-coil transformation in amylopectin, but also with an important swelling, were separated into a volume increase associated with swelling and a volume decrease associated with the transition itself. Thermodynamic parameters for this transition together with their pressure dependencies have been obtained from four independent experiments at each pressure. The data are thermodynamically consistent, but are poorly described by the Clapeyron equation. The negative volume change of the slow exothermic transition (A) appearing just after the main endothermic transition (M) is small, spread out over a wide temperature interval, and occurs at higher temperatures with increasing pressures. This transition is probably associated with reassociation of the unwound helixes of amylopectin with parts of amylopectin molecules other than their original helix duplex partner. The positive volume change of the high-temperature, endothermic transition (N) with a small enthalpy change is probably associated with a nematic-isotropic transformation ending the formation of a homogeneous SOL phase (in the sense of Flory), and is also pushed to higher temperatures with increasing pressures. Knowledge of the state of wheat starch

  10. Ozone sonde measurements aboard long-range boundary-layer pressurized balloons over the western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Gheusi, François; Barret, Brice; Verdier, Nicolas; Dulac, François; Durand, Pierre; Jambert, Corinne

    Since few years, the French space agency CNES has developed boundary-layer pressurized balloons (BLPBs) with the capability to transport scientific payloads at isopicnic level over very long distances and durations (up to several weeks in absence of navigation limits). However, the autonomy of conventional electro-chemical cell (ECC) ozone sondes, that are widely used for tropospheric and stratospheric soundings, is limited to few hours due to power consumption and electrolyte evaporation (due to air bubbling in the cathode solution). In collaboration with the French research community, CNES has developed a new ozone payload suited for long duration flights aboard BLPBs. The mechanical elements (Teflon pump and motor) and the electro-chemical cell of conventional ECC sondes have been kept but the electronic implementation is entirely new. The main feature is the possibility of programming periodic measurement sequences -- with possible remote control during the flight. To increase the ozone sonde autonomy, the strategy has been adopted of short measurement sequences (typically 3 min) regularly spaced in time (e.g. every 15 min, which is usually sufficient for air quality studies). The rest of the time, the sonde is left at rest (pump motor off). The response time of an ECC sonde to an ozone concentration step is below one minute. Therefore, the typical measurement sequence is composed of a one-minute spin-up period after the pump has been turned on, followed by a two-minute acquisition period. (Note that the time intervals given here are indicative. All can be adjusted before and during the flight.) Results of a preliminary ground-based test in spring 2012 will be first presented. The sonde provided correct ozone concentrations against a reference UV analyzer every 15 minutes during 4 days. Then, we will illustrate results from 16 BLBP flights launched in the low troposphere over the Mediterranean during the three summer field campaings of the coordinated project

  11. PaR-PaR laboratory automation platform.

    PubMed

    Linshiz, Gregory; Stawski, Nina; Poust, Sean; Bi, Changhao; Keasling, Jay D; Hillson, Nathan J

    2013-05-17

    Labor-intensive multistep biological tasks, such as the construction and cloning of DNA molecules, are prime candidates for laboratory automation. Flexible and biology-friendly operation of robotic equipment is key to its successful integration in biological laboratories, and the efforts required to operate a robot must be much smaller than the alternative manual lab work. To achieve these goals, a simple high-level biology-friendly robot programming language is needed. We have developed and experimentally validated such a language: Programming a Robot (PaR-PaR). The syntax and compiler for the language are based on computer science principles and a deep understanding of biological workflows. PaR-PaR allows researchers to use liquid-handling robots effectively, enabling experiments that would not have been considered previously. After minimal training, a biologist can independently write complicated protocols for a robot within an hour. Adoption of PaR-PaR as a standard cross-platform language would enable hand-written or software-generated robotic protocols to be shared across laboratories.

  12. PaR-PaR Laboratory Automation Platform

    SciTech Connect

    Linshiz, G; Stawski, N; Poust, S; Bi, CH; Keasling, JD; Hilson, NJ

    2013-05-01

    Labor-intensive multistep biological tasks, such as the construction and cloning of DNA molecules, are prime candidates for laboratory automation. Flexible and biology-friendly operation of robotic equipment is key to its successful integration in biological laboratories, and the efforts required to operate a robot must be much smaller than the alternative manual lab work. To achieve these goals, a simple high-level biology-friendly robot programming language is needed. We have developed and experimentally validated such a language: Programming a Robot (PaR-PaR). The syntax and compiler for the language are based on computer science principles and a deep understanding of biological workflows. PaR-PaR allows researchers to use liquid-handling robots effectively, enabling experiments that would not have been considered previously. After minimal training, a biologist can independently write complicated protocols for a robot within an hour. Adoption of PaR-PaR as a standard cross-platform language would enable hand-written or software-generated robotic protocols to be shared across laboratories.

  13. Fiber loop ring down for static ice pressure detection

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Yang, Lingzhen; Zhang, Zongwei; Yang, Jianjun; Wang, Juanfen; Zhang, Li; Deng, Xiao; Zhang, Zhaoxia

    2017-07-01

    We studied static ice pressure detection of hydraulic structures based on fiber loop ring down technology. Our detection system consists of a mode-locked laser, two 2 × 1 optical fiber couplers, a piece of single-mode fiber, the on-line micro-bend fiber sensor and a photo-detector. The static ice pressure was monitored based on measuring the change of the ring down time induced by external ice pressure on on-line micro-bend fiber sensor. We monitored the static ice pressure during ice growth and melting from -10 °C to 6 °C. The detection sensitivity is 0.00998/(μs·kPa). The proposed pressure sensing method has many advantages such as free from the fluctuation of the light power, simple structure, fast response and high sensitivity.

  14. Vapor pressures and calculated heats of vaporization of concentrated nitric acid solutions in the composition range 71 to 89 percent nitrogen dioxide, 1 to 10 percent water, and in the temperature range 10 to 60 degrees C

    NASA Technical Reports Server (NTRS)

    Mckeown, A B; Belles, Frank E

    1954-01-01

    Total vapor pressures were measured for 16 acid mixtures of the ternary system nitric acid, nitrogen dioxide, and water within the temperature range 10 degrees to 60 degrees Celsius, and with the composition range 71 to 89 weight percent nitric acid, 7 to 20 weight percent nitrogen dioxide, and 1 to 10 weight percent water. Heats of vaporization were calculated from the vapor pressure measurements for each sample for the temperatures 25, 40, and 60 degrees Celsius. The ullage of the apparatus used for the measurements was 0.46. Ternary diagrams showing isobars as a function of composition of the system were constructed from experimental and interpolated data for the temperatures 25, 40, 45, and 60 degrees C and are presented herein.

  15. A high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging.

    PubMed

    Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

    2014-12-16

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in "H" type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than -0.01% F.S/°C in the range of -40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

  16. A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging

    PubMed Central

    Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

    2014-01-01

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S. PMID:25521385

  17. Effect of dispersive long-range corrections to the pressure tensor: the vapour-liquid interfacial properties of the Lennard-Jones system revisited.

    PubMed

    Martínez-Ruiz, F J; Blas, F J; Mendiboure, B; Moreno-Ventas Bravo, A I

    2014-11-14

    We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264-6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r(c) = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r(c) = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness

  18. Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

    SciTech Connect

    Martínez-Ruiz, F. J.; Blas, F. J.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.

    2014-11-14

    We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r{sub c} = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r{sub c} = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial

  19. Design, fabrication and testing of a micro-Venturi tube for fluid manipulation in a microfluidic system

    NASA Astrophysics Data System (ADS)

    Yu, H.; Li, D.; Roberts, R. C.; Xu, K.; Tien, N. C.

    2012-03-01

    In this paper, a micro-Venturi tube fabricated with polydimethylsiloxane (PDMS) is studied for interstitial fluid (ISF) transdermal extraction and fluid manipulation in a microfluidic system toward the application of continuous glucose monitoring. The fabrication structure parameters of the PDMS Venturi tube were theoretically analyzed and experimentally validated against the output vacuum efficiency of the Venturi structure. The optimization methods of the Venturi structure were also discussed. In addition, an optimized micro-Venturi structure was proposed and fabricated. A vacuum pressure of less than 86 kPa had been achieved when an external pressure of 240 kPa was applied to this optimized Venturi tube. Both experimental and mathematical results demonstrate the potential applicability of the micro-Venturi tube in ISF transdermal extraction and fluid manipulation.

  20. Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty.

    PubMed

    Smith, Matthew E; Tysome, James R

    2017-01-01

    Objective Balloon eustachian tuboplasty (BET) has entered clinical use as a treatment for eustachian tube dysfunction. Some surgeons perform myringotomy prior to BET due to concerns that the increase in middle ear (ME) pressure caused by BET may cause otic barotrauma. We investigated the ME pressure changes occurring during BET in cadavers. Study design Human cadaver investigation of a surgical technique Setting Laboratory study at a tertiary referral center. Subjects and Methods ME pressures were recorded from fresh-frozen cadavers, and BET was performed with the Bielefeld balloon catheter inflated to 10 bar. Peak ME pressures were recorded during catheter insertion, inflation, deflation, and removal. A second pressure measurement was taken 15 seconds after each stage to assess the residual pressures. All BET procedures were repeated at least once. Where transmastoid recordings were made, BET was repeated, measuring pressure via a myringotomy to ensure equivalence. Results Data from 25 procedures in 13 ears (9 heads) were analyzed. A consistent pattern of ME pressure change was observed in all cases. Positive pressures occurred on insertion (maximum, 26 daPa) and inflation (maximum, 99 daPa) and negative pressures on deflation (maximum, -46 daPa) and removal (maximum, -42 daPa). There were no significant pressure differences between first and second procedures, except at 15 seconds after insertion ( P = .04). Conclusion In adult cadaveric specimens, BET induces ME pressures within the normal physiologic range. On this basis, routine myringotomy prior to BET in adults is not necessary.

  1. Development, Fabrication, and Characterization of Hydrogel Based Piezoresistive Pressure Sensors with Perforated Diaphragms

    PubMed Central

    Orthner, M.P.; Buetefisch, Sebastian; Magda, J.; Rieth, L.W.; Solzbacher, F.

    2010-01-01

    Hydrogels have been demonstrated to swell in response to a number of external stimuli including pH, CO2, glucose, and ionic strength making them useful for detection of metabolic analytes. To measure hydrogel swelling pressure, we have fabricated and tested novel perforated diaphragm piezoresistive pressure sensor arrays that couple the pressure sensing diaphragm with a perforated semi-permeable membrane. The 2×2 arrays measure approximately 3 × 5 mm2 and consist of four square sensing diaphragms with widths of 1.0, 1.25, and 1.5 mm used to measure full scale pressures of 50, 25, and 5 kPa, respectively. An optimized geometry of micro pores was etched in silicon diaphragm to allow analyte diffusion into the sensor cavity where the hydrogel material is located. The 14-step front side wafer process was carried out by a commercial foundry service (MSF, Frankfurt (Oder), Germany) and diaphragm pores were created using combination of potassium hydroxide (KOH) etching and deep reactive ion etching (DRIE). Sensor characterization was performed (without the use of hydrogels) using a custom bulge testing apparatus that simultaneously measured deflection, pressure, and electrical output. Test results are used to quantify the sensor sensitivity and demonstrate proof-of-concept. Simulations showed that the sensitivity was slightly improved for the perforated diaphragm designs while empirical electrical characterization showed that the perforated diaphragm sensors were slightly less sensitive than solid diaphragm sensors. This discrepancy is believed to be due to the influence of compressive stress found within passivation layers and poor etching uniformity. The new perforated diaphragm sensors were fully functional with sensitivities ranging from 23 to 252 μV/V-kPa (FSO= 5 to 80mV), and show a higher nonlinearity at elevated pressures than identical sensors with solid diaphragms. Sensors (1.5×1.5 mm2) with perforated diaphragms (pores=40 μm) have a nonlinearity of

  2. A highly sensitive pressure sensor using a double-layered graphene structure for tactile sensing.

    PubMed

    Chun, Sungwoo; Kim, Youngjun; Oh, Hyeong-Sik; Bae, Giyeol; Park, Wanjun

    2015-07-21

    In this paper, we propose a graphene sensor using two separated single-layered graphenes on a flexible substrate for use as a pressure sensor, such as for soft electronics. The working pressure corresponds to the range in which human perception recognizes surface morphologies. A specific design of the sensor structure drives the piezoresistive character due to the contact resistance between two graphene layers and the electromechanical properties of graphene itself. Accordingly, sensitivity in resistance change is given by two modes for low pressure (-0.24 kPa(-1)) and high pressure (0.039 kPa(-1)) with a crossover pressure (700 Pa). This sensor can detect infinitesimal pressure as low as 0.3 Pa with uniformly applied vertical force. With the attachment of the artificial fingerprint structure (AFPS) on the sensor, the detection ability for both the locally generated shear force and actual human touch confirms recognition of the surface morphology constructed by periodic structures.

  3. Rapid and conservative ablation and modification of enamel, dentin, and alveolar bone using a high repetition rate transverse excited atmospheric pressure CO2 laser operating at lambda=9.3 micro.

    PubMed

    Fan, Kenneth; Bell, Paul; Fried, Daniel

    2006-01-01

    Transverse excited atmospheric pressure (TEA) CO(2) lasers tuned to the strong mineral absorption of hydroxyapatite near lambda=9 microm are well suited for the efficient ablation of dental hard tissues if the laser pulse is stretched to greater than 5 to 10 micros to avoid plasma shielding phenomena. Such CO(2) lasers are capable of operating at high repetition rates for the rapid removal of dental hard tissues. The purpose of this study was to test the hypothesis that stretched lambda=9.3-microA CO(2) laser pulses can produce lateral incisions in enamel, dentin, and alveolar bone for dental restorations and implants at repetition rates as high as 400 Hz without peripheral thermal damage. The single pulse ablation rates through enamel, dentin, and bone were determined for incident fluence ranging from (1 to 160 J/m(2)) for laser pulses from 5 to 18 mus in duration. Lateral incisions were produced in hard tissue samples using a computer-controlled scanning stage and water spray, and the crater morphology and chemical composition were measured using optical microscopy and high-resolution synchrotron radiation infrared spectromicroscopy. The residual energy remaining in tooth samples was measured to be 30 to 40% for enamel and 20 to 30% for dentin without water cooling, under optimum irradiation intensities, significantly lower than for longer CO(2) laser pulses. The transmission through 2-m length 300-, 500-, 750-, and 1000-microm silica hollow waveguides was measured and 80% transmission was achieved with 40 mJ per pulse. These results suggest that high repetition rate TEA CO(2) laser systems operating at lambda=9.3 microm with pulse durations of 10 to 20 micros are well suited for dental applications.

  4. Refractive index of r-cut sapphire under shock pressure range 5 to 65 GPa

    SciTech Connect

    Cao, Xiuxia; Li, Jiabo; Li, Jun; Li, Xuhai; Xu, Liang; Wang, Yuan; Zhu, Wenjun; Meng, Chuanmin; Zhou, Xianming

    2014-09-07

    High-pressure refractive index of optical window materials not only can provide information on electronic polarizability and band-gap structure, but also is important for velocity correction in particle-velocity measurement with laser interferometers. In this work, the refractive index of r-cut sapphire window at 1550 nm wavelength was measured under shock pressures of 5–65 GPa. The refractive index (n) decreases linearly with increasing shock density (ρ) for shock stress above the Hugoniot elastic limit (HEL): n = 2.0485 (± 0.0197) − 0.0729 (± 0.0043)ρ, while n remains nearly a constant for elastic shocks. This behavior is attributed to the transition from elastic (below HEL) to heterogeneous plastic deformation (above HEL). Based on the obtained refractive index-density relationship, polarizability of the shocked sapphire was also obtained.

  5. High frequency dynamic pressure calibration technique

    NASA Technical Reports Server (NTRS)

    Davis, P. A.; Zasimowich, R. F.

    1985-01-01

    A high frequency dynamic calibration technique for pressure transducers has been developed using a siren pressure generator (SPG). The SPG is an inlet-area-modulated device generating oscillating waveforms with dynamic pressure amplitudes up to 58.6 kPa (8.5 psi) in a frequency range of 1 to 10 kHz. A description of the generator, its operating characteristics and instrumentation used for pressure amplitude and frequency measurements is given. Waveform oscillographs and spectral analysis of the pressure transducers' output signals are presented.

  6. High frequency dynamic pressure calibration technique

    NASA Astrophysics Data System (ADS)

    Davis, P. A.; Zasimowich, R. F.

    A high frequency dynamic calibration technique for pressure transducers has been developed using a siren pressure generator (SPG). The SPG is an inlet-area-modulated device generating oscillating waveforms with dynamic pressure amplitudes up to 58.6 kPa (8.5 psi) in a frequency range of 1 to 10 kHz. A description of the generator, its operating characteristics and instrumentation used for pressure amplitude and frequency measurements is given. Waveform oscillographs and spectral analysis of the pressure transducers' output signals are presented.

  7. Critical evaluation of ex vivo restoration of carious equine maxillary cheek teeth infundibulae following high-pressure gas and micro-particle abrasion.

    PubMed

    Dixon, P M; Savill, D; Horbyl, A; Reardon, R J M; Liuti, T

    2014-06-01

    Infundibular caries of the equine maxillary cheek teeth is an important disorder that can lead to dental fracture or apical infection. Treatment by removing food debris and carious dental tissue from affected infundibulae using high-pressure abrasion with aluminium hydroxide micro-particles, followed by filling the cleaned defect with endodontic restorative materials is a recommended treatment. However, although anecdotally considered a successful treatment option, there is currently no objective evidence to support this claim. Forty maxillary cheek teeth (CT) that contained 55 infundibulae with caries (mainly grade 2) were extracted post-mortem from 21 adult horses. Five of the CT were sectioned prior to treatment to facilitate visual examination of the carious infundibulae. The remaining carious infundibulae were cleaned using high-pressure abrasion with aluminium hydroxide particles and five CT were sectioned to assess the efficacy of this cleaning process. The remaining 30 CT containing 39 carious infundibulae were then filled with a composite restorative material. The efficacy of this restoration was assessed by computed tomography imaging followed by direct visual examination after sectioning the teeth. Only 46% (18/39) of restored infundibulae, all with shallow (mean 9.6 mm deep) defects, were fully cleaned of food debris and carious material, and filled with restorative material to their full depth. Of these 18, 11 had peripheral defects around the restoration, leaving just 18% (7/39) of restorations without any gross defects. The remaining 54% (21/39) of infundibulae (mean depth of infundibular caries defect, 18.3 mm) still contained food debris and/or carious material in more apical locations, with infundibulae with the deepest caries defects being the least effectively cleaned. The findings of this study indicate that high-pressure micro-particle abrasion is only effective in cleaning food debris from shallow, carious CT infundibulae and consequently

  8. On the pressure difference ranges which assure a specified gap size for semiconductor crystals grown in terrestrial dewetted Bridgman

    NASA Astrophysics Data System (ADS)

    Braescu, L.

    2010-04-01

    The complexity of the dewetting phenomenon on the ground consists mainly in the presence of the hydrostatic pressure which should be counterbalanced by a supplementary gas pressure difference ΔP=Pc-Ph between the cold and hot sides of the sample. The experiments have shown that using uncoated and coated crucibles, detached and partially detached growth can be obtained; dewetting became unsuccessful when the liquid-solid interface changed its shape—phenomenon which proved connection between the meniscus shape, pressure difference and stable dewetting. Because the interest is to grow crystals with specified gap size, the ΔP limits and the corresponding menisci shapes for which dewetting is feasible are first established, on the base of the theoretical and computational investigations. Then, for the obtained menisci, the static stability via the conjugate point criterion of the calculus of variations is studied in the cases of the classical semiconductors grown in (i) uncoated crucibles (i.e., the wetting angle θc and growth angle αe satisfy the inequality θc+αe<180∘) and (ii) coated crucibles or pollution ( θc+αe≥180∘). In this way, gap thickness limitations for which the menisci are physically realizable are obtained. Numerical results are performed for InSb crystal grown in uncoated ampoule, and for Ge crystal grown in coated ampoule.

  9. Final report on regional key comparison COOMET.M.P-K2: Hydraulic gauge pressure in the range 10 MPa to 100 MPa

    NASA Astrophysics Data System (ADS)

    Dapkeviciene, K.; Sabuga, W.; Waller, B.; Farar, P.; Kiselev, Yu; Saczuk, K.; Sandu, I.

    2011-01-01

    This report describes a COOMET key comparison of hydraulic pressure standards of seven national metrology institutes that was carried out in the period from June 2005 to July 2008 in order to determine their degrees of equivalence in the range 10 MPa to 100 MPa of the gauge pressure. The pilot laboratory was VMT/VMC. The pressure standards of the participating NMIs were pressure balances of different design, equipped with piston-cylinder assemblies. The transfer standard was a pressure balance, equipped with a 9.8 mm2 piston-cylinder assembly, manufactured by SMU. The participants reported the pressure-dependent effective areas of the transfer standard at specified pressures. The reference values were calculated as the weighted means of PTB, NPL, SMU and VNIIM, which have primary pressure standards. The results by all participants agree with the reference values and with each other within the expanded uncertainties calculated with a coverage factor (k = 2). At the level of standard uncertainties there is a full agreement between 10 MPa and 100 MPa. The results of this comparison were linked to those of key comparison CCM.P-K7. Degrees of equivalence and expanded (k = 2) uncertainties between the COOMET and laboratories having participated in other KCs: CCM.P-K7, APMP.M.P-K7, EUROMET.M.P-K4 and APM.M.P-K7.1 at measured pressure points are presented in the final report. The results of the comparison demonstrate equivalence of the laboratory standards and, for laboratories the CMCs of which are not yet presented in the KCDB, this comparison provides a basis for submission in the range from 10 MPa to 100 MPa of hydraulic gauge pressure. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  10. Change in serum TSH levels within the reference range was associated with variation of future blood pressure: a 5-year follow-up study.

    PubMed

    Jiang, F; Liu, A; Lai, Y; Yu, X; Li, C; Han, C; Zhang, Y; Wang, X; Wang, Z; Bao, S; Lv, N; Jin, M; Yang, F; Fan, Y; Jin, T; Zhao, W; Shan, Z; Teng, W

    2017-04-01

    Controversy exists on the relationship between serum thyrotropin (TSH) and blood pressure, and only a few prospective studies are available up to now. The study aimed to investigate the association between serum TSH within the reference range and blood pressure through a 5-year follow-up study. A total of 623 subjects with normal TSH were followed up for 5 years, including the measurement of demographic data, blood pressure, height, weight and serum TSH. Finally, 531 subjects were included in this prospective study. Body mass index (BMI), prevalence of hypertension, and systolic and diastolic blood pressure were all higher at follow-up than at baseline. Adjusted for age, gender, smoking status, BMI and homoeostasis model assessment of insulin resistance (HOMA-IR) at baseline, multiple linear regression analyses found no relationship between serum TSH at baseline and levels of blood pressure at follow-up, but the changes in serum TSH levels during follow-up was positively associated with the changes in systolic blood pressure (B=2.134, P<0.05), which became more significant in women but not significant in men. The change of systolic blood pressure in group of TSH increase >0.5 mIU l(-1) was significantly higher than in group of TSH decrease >0.5 mIU l(-1) within reference, after adjusting for age, gender, smoking status, BMI and HOMA-IR at baseline. This result became more significant in women, but no statistical significance was observed in men. Co-variation with serum TSH levels and blood pressure was observed during 5-year follow-up among people with normal TSH.

  11. SFE/SFHTA/AFCE consensus on primary aldosteronism, part 1: Epidemiology of PA, who should be screened for sporadic PA?

    PubMed

    Baguet, Jean-Philippe; Steichen, Olivier; Mounier-Véhier, Claire; Gosse, Philippe

    2016-07-01

    Depending on the study, the prevalence of primary aldosteronism (PA) in patients with hypertension varies from 6 to 18%. Prevalence is higher in each of the following conditions, any one of which requires screening for PA: severe hypertension (systolic blood pressure [BP]≥180mmHg and/or diastolic BP≥110mmHg); resistant hypertension (systolic BP≥140mmHg and/or diastolic BP≥90mmHg despite adherence to a tritherapy including a thiazide diuretic); hypertension associated with hypokalemia (either spontaneous or associated with a diuretic); Hypertension or hypokalemia associated with adrenal incidentaloma. It should be borne in mind that PA can induce hypertension without hypokalemia or, less frequently, hypokalemia without hypertension. Finally, as cardiovascular and renal morbidity in PA is greater than in essential hypertension of equivalent level, screening for PA is indicated when cardiovascular or renal morbidity is more severe than predicted from BP level.

  12. Isotropic Negative Area Compressibility over Large Pressure Range in Potassium Beryllium Fluoroborate and its Potential Applications in Deep Ultraviolet Region.

    PubMed

    Jiang, Xingxing; Luo, Siyang; Kang, Lei; Gong, Pifu; Yao, Wenjiao; Huang, Hongwei; Li, Wei; Huang, Rongjin; Wang, Wei; Li, Yanchun; Li, Xiaodong; Wu, Xiang; Lu, Peixiang; Li, Laifeng; Chen, Chuangtian; Lin, Zheshuai

    2015-09-02

    Isotropic negative area compressibility, which is very rare, is observed in KBBF and the related mechanism is investigated by combined high-pressure X-ray diffraction (XRD) experiments and first-principles calculations. The strong mechanical anisotropy leads to a large Poisson's ratio and high figure of merit for the acoustic-optics effect, giving KBBF potential applications as smart strain converters and deep-ultraviolet (DUV) acoustic-optic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Green's Function Approach to PIV Pressure Estimates with an Application to Micro Energy Harvesters in Turbulent and Vortical Flows

    NASA Astrophysics Data System (ADS)

    Goushcha, Oleg

    In the present work we demonstrate the feasibility to harness energy from fluid flows by using piezoelectric generators. These ac-coupled devices convert fluid kinetic energy, which otherwise would be wasted, into electrical energy. The available power density in a flowing fluid is proportional to the cube of its velocity and if it is properly harvested can be used for continuously powering very small electronic devices or can be rectified and stored for intermittent use. A key quantity in these applications which affects the performance is the forcing which the fluid exerts on the harvesters. An analytical solution is presented for the Pressure Poisson Equation (PPE) that uses Particle Image Velocimetry (PIV) field data to find the pressure in a flow domain and to calculate the pressure and therefore the force exerted by the fluid on the solid surface. The solution provides a favorable method of calculating pressure field from PIV data as it eliminates the need to compute higher order derivatives of velocity on the domain that are present in viscous terms as well as eliminates the need to integrate Navier-Stokes equations to find the pressure along the boundaries of interest. The solution is validated against a theoretical solution for a pressure distribution inside a tornado-like vortex; pressure solutions obtained by derivative momentum transform method for a vortex flow and some experimental results for the pressure distribution inside a turbulent boundary layer. Several experiments were carried out in which pressure was calculated using PPE: i) a discrete vortex passing over a simple cantilever beam harvester ii) a simple cantilever harvester placed in the boundary layer iii) a self-excited harvester placed in the free stream flow. In a discrete vortex experiment, the self-propelled vortex is passed over the cantilever beam. The pressure distribution and the net force of the beam are calculated by solving PPE as the vortex passes over the beam. In a boundary

  14. Impact of selenization pressure on the micro-structural properties of Cu2ZnSnSe4 thin films

    NASA Astrophysics Data System (ADS)

    Nagapure, Dipak Ramdas; Patil, Rhishikesh Mahadev; Chandra, G. Hema; Sunil, M. Anantha; Subbaiah, Y. P. Venkata; Gupta, Mukul; Prasada Rao, R.

    2017-10-01

    The Cu2ZnSnSe4(CZTSe) thin films were prepared by a two-step process consisting of high vacuum sequential evaporation of precursors stack (Sn/Se/ZnSe/Se/Cu/Se) in 4-folds followed by selenization at 350 °C in tubular furnace under varied argon gas pressure from 1 mbar to 600 mbar with an interval of 150 mbar. The Cu/(Zn + Sn) and Zn/Sn ratios found to vary from 1.22 to 0.93 and 1.94 to 1.08 with an increase in pressure and the stacks selenized for 600 mbar showed nearly stoichiometric composition with slight Cu-poor and Zn-rich values required for CZTSe growth. The X-ray diffraction studies revealed similar diffraction pattern with a preferred orientation along (112) plane, indicating the formation of kesterite-type CZTSe for all the selenization pressures. Raman spectra recorded using different excitation wavelength sources (785, 532 and 458 nm), revealed two main peaks at 192 and 172 cm-1 and two supplementary weak peaks at 82 and 232 cm-1 corresponding to kesterite-ordered CZTSe phase for films selenized at a pressure of 600 mbar. Appreciable changes in morphology have been noticed with increase in selenization pressure from low dense irregular rod like morphology to compact spherical grain morphology. All the samples showed high absorption coefficient (>104cm-1). A slight variation in optical band gap from 0.90 to 1.01 eV was found with increase in selenization pressure. The Hall effect measurements reveal that all the films are p-type conductive. The precursor stack films selenized at 600 mbar exhibit high mobility of 7.88 cm2(Vs)-1 with lower carrier concentration of 2.54 × 1019 cm-3 and resistivity of an order of 10-2 Ωcm, respectively.

  15. New Raman measurements for H2O ice VII in the range of 300 cm-1 to 4000 cm-1 at pressures up to 120 GPa

    NASA Astrophysics Data System (ADS)

    Zha, Chang-Sheng; Tse, John S.; Bassett, William A.

    2016-09-01

    Raman spectroscopic measurements for H2O ice VII have been conducted to 120 GPa at 300 K in the spectroscopic range of 300-4000 cm-1. Both moissanite and diamond anvils were used for the experiments. This overcomes the problems of overlapping spectra between the diamond anvil and sample, which had prevented the observation of the stretching modes at pressures higher than ˜23 GPa in all previous measurements. The new results reveal many bands which have not been reported before. The pressure dependences of the Raman modes show anomalous changes at 13-15, ˜27, ˜44, ˜60, and 90 GPa, implying possible structural changes at these pressures. The new results demonstrate that the predicted symmetric hydrogen bond phase X transition does not occur below 120 GPa.

  16. New Raman measurements for H2O ice VII in the range of 300 cm(-1) to 4000 cm(-1) at pressures up to 120 GPa.

    PubMed

    Zha, Chang-Sheng; Tse, John S; Bassett, William A

    2016-09-28

    Raman spectroscopic measurements for H2O ice VII have been conducted to 120 GPa at 300 K in the spectroscopic range of 300-4000 cm(-1). Both moissanite and diamond anvils were used for the experiments. This overcomes the problems of overlapping spectra between the diamond anvil and sample, which had prevented the observation of the stretching modes at pressures higher than ∼23 GPa in all previous measurements. The new results reveal many bands which have not been reported before. The pressure dependences of the Raman modes show anomalous changes at 13-15, ∼27, ∼44, ∼60, and 90 GPa, implying possible structural changes at these pressures. The new results demonstrate that the predicted symmetric hydrogen bond phase X transition does not occur below 120 GPa.

  17. Constraining the Depth of a Martian Magma Ocean through Metal-Silicate Partitioning Experiments: The Role of Different Datasets and the Range of Pressure and Temperature Conditions

    NASA Technical Reports Server (NTRS)

    Righter, K.; Chabot, N.L.

    2009-01-01

    Mars accretion is known to be fast compared to Earth. Basaltic samples provide a probe into the interior and allow reconstruction of siderophile element contents of the mantle. These estimates can be used to estimate conditions of core formation, as for Earth. Although many assume that Mars went through a magma ocean stage, and possibly even complete melting, the siderophile element content of Mars mantle is consistent with relatively low pressure and temperature (PT) conditions, implying only shallow melting, near 7 GPa and 2073 K. This is a pressure range where some have proposed a change in siderophile element partitioning behavior. We will examine the databases used for parameterization and split them into a low and higher pressure regime to see if the methods used to reach this conclusion agree for the two sets of data.

  18. Photogrammetric measurement of 3D freeform millimetre-sized objects with micro features: an experimental validation of the close-range camera calibration model for narrow angles of view

    NASA Astrophysics Data System (ADS)

    Percoco, Gianluca; Sánchez Salmerón, Antonio J.

    2015-09-01

    The measurement of millimetre and micro-scale features is performed by high-cost systems based on technologies with narrow working ranges to accurately control the position of the sensors. Photogrammetry would lower the costs of 3D inspection of micro-features and would be applicable to the inspection of non-removable micro parts of large objects too. Unfortunately, the behaviour of photogrammetry is not known when photogrammetry is applied to micro-features. In this paper, the authors address these issues towards the application of digital close-range photogrammetry (DCRP) to the micro-scale, taking into account that in literature there are research papers stating that an angle of view (AOV) around 10° is the lower limit to the application of the traditional pinhole close-range calibration model (CRCM), which is the basis of DCRP. At first a general calibration procedure is introduced, with the aid of an open-source software library, to calibrate narrow AOV cameras with the CRCM. Subsequently the procedure is validated using a reflex camera with a 60 mm macro lens, equipped with extension tubes (20 and 32 mm) achieving magnification of up to 2 times approximately, to verify literature findings with experimental photogrammetric 3D measurements of millimetre-sized objects with micro-features. The limitation experienced by the laser printing technology, used to produce the bi-dimensional pattern on common paper, has been overcome using an accurate pattern manufactured with a photolithographic process. The results of the experimental activity prove that the CRCM is valid for AOVs down to 3.4° and that DCRP results are comparable with the results of existing and more expensive commercial techniques.

  19. Standard thermodynamic properties of H3PO4(aq) over a wide range of temperatures and pressures.

    PubMed

    Ballerat-Busserolles, Karine; Sedlbauer, Josef; Majer, Vladimir

    2007-01-11

    The densities and heat capacities of solutions of phosphoric acid, 0.05 to 1 mol kg-1, were measured using flow vibrating tube densitometry and differential Picker-type calorimetry at temperatures up to 623 K and at pressures up to 28 MPa. The standard molar volumes and heat capacities of molecular H3PO4(aq) were obtained, via the apparent molar properties corrected for partial dissociation, by extrapolation to infinite dilution. The data on standard derivative properties were correlated simultaneously with the dissociation constants of phosphoric acid from the literature using the theoretically founded SOCW model. This made it possible to describe the standard thermodynamic properties, particularly the standard chemical potential, of both molecular and ionized phosphoric acid at temperatures up to at least 623 K and at pressures up to 200 MPa. This representation allows one to easily calculate the first-degree dissociation constant of H3PO4(aq). The performance of the SOCW model was compared with the other approaches for calculating the high-temperature dissociation constant of the phosphoric acid. Using the standard derivative properties, sensitively reflecting the interactions between the solute and the solvent, the high-temperature behavior of H3PO4(aq) is compared with that of other weak acids.

  20. An Investigation Into the Range of Sea State Conditions Necessary for the Generation of Seafloor Pressures and Secondary Microseisms in the Northeast Atlantic, West of Ireland

    NASA Astrophysics Data System (ADS)

    Donne, S. E.; Bean, C. J.; Dias, F.; Christodoulides, P.

    2016-12-01

    Ocean generated microseisms propagate mainly as Rayleigh and Love waves and are a result of the mechanical coupling between the ocean and the solid earth. There are two types of microseism, primary and secondary. Primary microseisms are generated when a travelling ocean wave enters shallow water or coastal regions and the associated pressure profile, which decays exponentially with depth, is non zero at the seafloor. Secondary microseisms on the other hand are generated by the second order non linear effect associated with a standing wave, through ocean wave- wave interactions. Secondary microseisms can therefore be generated in any water depth. The conditions required to generate secondary microseisms through wave- wave interactions are presented in Longuet-Higgins (1950) through the interaction of two travelling waves with the same wave period at an angle of 180 degrees. Equivalent surface pressure density (p2l) is modelled within the numerical ocean wave model, Wavewatch III and is the microseism source term. This work investigates the theoretical pressures associated with the interaction of two travelling waves with varying wave periods and wave amplitude at a range of incident angles. Theoretical seafloor pressures are calculated off the Southwest coast of Ireland and are compared with terrestrially recorded microseism data as well as oceanographic parameters and measured seafloor pressures. The results indicate that a broad range of sea state conditions can generate second order pressures at the seafloor which are consistent with measured seafloor measurements in the same location. While secondary microseism amplitudes may be used to infer ocean wave parameters this work has implications for doing so and these will be presented. Local seismic arrays in Ireland allow us to monitor and track the spatiotemporal evolution of these microseism source regions.

  1. Rapid prototyping of microfluidic devices with integrated wrinkled gold micro-/nano textured electrodes for electrochemical analysis.

    PubMed

    Gabardo, C M; Adams-McGavin, R C; Vanderfleet, O M; Soleymani, L

    2015-08-21

    Fully-integrated electro-fluidic systems with micro-/nano-scale features have a wide range of applications in lab-on-a-chip systems used for biosensing, biological sample processing, and environmental monitoring. Rapid prototyping of application-specific electro-fluidic systems is envisioned to facilitate the testing, validation, and market translation of several lab-on-a-chip systems. Towards this goal, we developed a rapid prototyping process for creating wrinkled micro-/nano-textured electrodes on shrink memory polymers, fabricating microfluidics using molds patterned by a craft-cutter, and bonding electrical and fluidic circuitries using a PDMS partial curing method optimized for creating void-free bonds at the side walls and surfaces of tall (>5 μm) micro-/nano-textured wrinkled electrodes. The resulting electro-fluidic devices, featuring closely spaced high topography electrodes for electrochemical analysis, can withstand flow-rates and burst pressures larger than 25 mL min(-1) and 125 kPa, respectively. In addition, the fully-integrated electrochemical flow-cell developed here demonstrates excellent electrochemical behaviour, with negligible scan to scan variation for over 100 cyclic voltammetry scans, and expected redox signatures measured under various voltage scan rates and fluidic flow rates.

  2. A dynamic pressure source for the calibration of pressure transducers

    NASA Technical Reports Server (NTRS)

    Vezzetti, C. F.; Hilten, J. S.; Mayo-Wells, J. F.; Lederer, P. S.

    1976-01-01

    A dynamic pressure source is described for producing sinusoidally varying pressures of up to 34 kPa zero to peak, over the frequency range of approximately 50 Hz to 2 kHz. The source is intended for the dynamic calibration of pressure transducers. The transducer to be calibrated is mounted near the base of the thick walled aluminum tube forming the vessel so that the pressure sensitive element is in contact with the liquid in the tube. A section of the tube is filled with small steel balls to damp the motion of the 10-St dimethyl siloxane working fluid in order to extend the useful frquency range to higher frequencies than would be provided by an undamped system. The dynamic response of six transducers provided by the sponsor was evaluated using the pressure sources; the results of these calibrations are given.

  3. Orion PA-1 Flight Test Crew Module Back at Dryden

    NASA Image and Video Library

    The boilerplate Orion crew module and separation ring that was flown in the Launch Abort system PA-1 flight test at White Sands Missile Range, N.M., May 6 were airlifted back to NASA Dryden at Edwa...

  4. Assessing the effectiveness of low-pressure ultraviolet light for inactivating Mycobacterium avium complex (MAC) micro-organisms

    EPA Science Inventory

    Aims: To assess low-pressure ultraviolet light (LP-UV) inactivation kinetics of Mycobacterium avium complex (MAC) strains in a water matrix using collimated beam apparatus. Methods and Results: Strains of M. avium (n = 3) and Mycobacterium intracellulare (n = 2) were exposed t...

  5. Assessing the effectiveness of low-pressure ultraviolet light for inactivating Mycobacterium avium complex (MAC) micro-organisms

    EPA Science Inventory

    Aims: To assess low-pressure ultraviolet light (LP-UV) inactivation kinetics of Mycobacterium avium complex (MAC) strains in a water matrix using collimated beam apparatus. Methods and Results: Strains of M. avium (n = 3) and Mycobacterium intracellulare (n = 2) were exposed t...

  6. The eutectic liquid composition in the Fe-Fe3S binary system at the core pressure range

    NASA Astrophysics Data System (ADS)

    Mori, Y.; Hirose, K.; Tateno, S.; Morard, G.; Ohishi, Y.

    2015-12-01

    Sulfur is considered to be an important component in the Earth's core because it is depleted in the crust and mantle compared to other volatile elements and often included in iron meteorites. Here we examine the liquidus phase relations in the Fe-Fe3S binary system between 38 and 138 GPa based on characterization of a sample recovered from a melting experiment at high pressure and temperature in a laser-heated diamond-anvil cell. Both Fe-8wt.%S and Fe-14wt.%S samples were employed as starting materials, which were homogeneous mixtures of fine-grain Fe and FeS (<1 μm) prepared by induction melting and rapid quenching technique [Morard et al., 2011 PCM]. We used a focused ion beam (FIB) equipped with energy dispersive X-ray spectrometry for textural and chemical characterizations of recovered samples. The samples exhibited a melting texture with quenched liquid alloy at the hottest part and solid Fe or Fe3S at its outside. In a couple of samples, the quenched liquid was in direct contact with solid Fe3S, and solid Fe was also present right next to Fe3S, suggesting that the composition of such liquid is close to a eutectic composition (~10 wt.% S at 66 GPa and ~12 wt.% S at 138 GPa). Indeed, this interpretation is consistent with the results of other experiments obtained in this study. Our data demonstrate that the eutectic liquid composition in the Fe-Fe3S binary system decreases its sulfur concentration with increasing pressure, which is in agreement with previous studies [Morard et al., 2008 EPSL; Kamada et al., 2012 EPSL]. The sulfur content in the eutectic liquid composition may be less than 10 wt.% at the inner core boundary pressure. The recent shock-wave study by Huang et al.[2013 GRL] suggested 10 wt.% S in the outer core, but the present study indicates that such liquid alloy with 10 wt.% S crystalizes the B2 phase of Fe-S alloy and thus does not support the sulfur-rich outer core.

  7. Effect of hydrostatic pressure on the conductivity of YBa2Cu3O7-δsingle crystals in a broad range of temperature and oxygen content

    NASA Astrophysics Data System (ADS)

    Vovk, R. V.; Khadzhai, G. Ya.; Dobrovolskiy, O. V.; Nazyrov, Z. F.; Kamchatnaya, S. N.

    2017-04-01

    The effect of external hydrostatic pressure on the electrical resistance of optimally doped and underdoped YBa2Cu3O7-δ single crystals is investigated in a broad temperature range, which includes the normal state and the region of superconducting fluctuations. The temperature dependences of the resistivity in the normal state are determined by scattering of charge carriers by phonons and defects. The application of pressure leads to significant changes in the electronic structure of the sample and reduces the degree of their defectiveness. This is accompanied by changeû in the lattice characteristics as the sample volume decreases. The fluctuation conductivity only exists within the range of ∼ 0.1Tc . With increasing δ the superconducting characteristics are close to the values typical for conventional low-temperature superconductors.

  8. Influence of ambient pressure on the ablation hole in femtosecond laser drilling Cu.

    PubMed

    Wang, Qinxin; Chen, Anmin; Li, Suyu; Qi, Hongxia; Qi, Ying; Hu, Zhan; Jin, Mingxing

    2015-09-20

    The holes were drilled by femtosecond laser pulse (800 nm, 100 fs) on Cu sheets at different ambient pressures. The pressure range was from 1 Pa to atmospheric pressure. The number of pulses to drill through the target, the stable photodiode signal, and the hole diameter were obtained as functions of ambient pressure. The morphology of the hole was observed by a scanning electron microscope (SEM). The result showed that the ambient pressure had significant influence on the morphology of the hole.

  9. Pressure-induced Crossover from Variable Range Hopping to Electron-Electron Interaction in the Organic Conductor (DOET)2BF4

    NASA Astrophysics Data System (ADS)

    Yasuzuka, Syuma; Murata, Keizo; Shimotori, Masahiro; Fujimoto, Tsutomu; Yamada, Jun‑ichi; Kikuchi, Koichi

    2006-02-01

    This paper reports the pressure effect on resistivity in the quasi two-dimensional (2D) organic conductor (DOET)2BF4 with orientational disorder of BF4 anions. At ambient pressure, the resistivity shows metal-insulator transition at 80 K and 2D variable range hopping (VRH) conduction below 80 K. The insulating behavior is suppressed by applying pressure and the temperature dependence of the resistivity shows the crossover from the 2D VRH to the logarithmic divergence as applied pressure increases. From the observation of the positive magnetoresistance, the logarithmic divergence of the resistivity is not attributed to the Anderson localization, but to the effect of the electron-electron interaction. This crossover is simply understood in terms of the screening effect on the random potential by increase of bandwidth due to applied pressure. It is found that a value of sheet conductance at low temperatures above 8 kbar, where the insulating state is almost suppressed, approaches to the minimum conductivity for a metallic state, σmin=e2/h=1/(25.8 kΩ), first proposed by Mott.

  10. Parallel-coupled micro-macro actuators

    SciTech Connect

    Morrell, J.B.; Salisbury, J.K.

    1998-07-01

    This paper presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the parallel-coupled micro-macro actuator, or PaCMMA. In this system, the micro-actuator is capable of high-bandwidth force control owing to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft, and increases the dynamic range of force. Performance improvement over single-actuator systems was expected in force control, impedance control, force distortion, and transient impact force reduction. Several theoretical performance limits are derived from the saturation limits of the system. A control law is presented. A prototype test bed was built and an experimental comparison was performed between this actuator concept and two single-actuator systems. A set of quantitative measures is proposed and the actuator system is evaluated against them with the following results: force bandwidth of 56 Hz, torque dynamic range of 800:1, peak torque of 1,040 mNm, and minimum torque of 1.3 mNm. Peak impact force, force distortion, and back-driven impedance of the PaCMMA system are shown to be better than either of the single-actuator configurations considered.

  11. Crystal-liquid-vapor equilibrium experiments at high temperature (less than or equal to 1800 C) and low, controlled oxygen and hydrogen pressure (10(-1) to 10(-9) PA)

    NASA Technical Reports Server (NTRS)

    Mysen, B. O.

    1987-01-01

    Evidence from carbonaceous chrondrites points to refractory oxides in the system CaO-MgO-Al2O3-TiO2-SiO2-Fe-O as being among the earliest phases to condense from the solar nebula. It is necessary to establish the equilibrium relationships between the relevant crystalline and amorphous phases before the chemical constraints can be meaningfully applied to models of solar system history. Preliminary experiments on earth show that such experiments are feasible. Earth-based experiments suffer from several unavoidable problems. These problems can be overcome by experimentation in the Space Station where the experiments can be conducted under near static pressure conditions and where total pressure equals the sum of controlled hydrogen and oxygen pressures and can be controlled for periods exceeding several hours.

  12. Sub-micro a-C:H patterning of silicon surfaces assisted by atmospheric-pressure plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Boileau, Alexis; Gries, Thomas; Noël, Cédric; Perito Cardoso, Rodrigo; Belmonte, Thierry

    2016-11-01

    Micro and nano-patterning of surfaces is an increasingly popular challenge in the field of the miniaturization of devices assembled via top-down approaches. This study demonstrates the possibility of depositing sub-micrometric localized coatings—spots, lines or even more complex shapes—made of amorphous hydrogenated carbon (a-C:H) thanks to a moving XY stage. Deposition was performed on silicon substrates using chemical vapor deposition assisted by an argon atmospheric-pressure plasma jet. Acetylene was injected into the post-discharge region as a precursor by means of a glass capillary with a sub-micrometric diameter. A parametric study was carried out to study the influence of the geometric configurations (capillary diameter and capillary-plasma distance) on the deposited coating. Thus, the patterns formed were investigated by scanning electron microscopy and atomic force microscopy. Furthermore, the chemical composition of large coated areas was investigated by Fourier transform infrared spectroscopy according to the chosen atmospheric environment. The observed chemical bonds show that reactions of the gaseous precursor in the discharge region and both chemical and morphological stability of the patterns after treatment are strongly dependent on the surrounding gas. Various sub-micrometric a-C:H shapes were successfully deposited under controlled atmospheric conditions using argon as inerting gas. Overall, this new process of micro-scale additive manufacturing by atmospheric plasma offers unusually high-resolution at low cost.

  13. Atmospheric Pressure Micro-Thermal-Plasma-Jet Crystallization of Amorphous Silicon Strips for High-Performance Thin Film Transistor Fabrication

    NASA Astrophysics Data System (ADS)

    Morisaki, Seiji; Nakatani, Taichi; Shin, Ryota; Higashi, Seiichiro

    2015-09-01

    Zone melting recrystallization (ZMR) of amorphous silicon (a-Si) strips by micro-thermal-plasma-jet (u-TPJ) irradiation is quite effective to suppress grain boundaries (GBs) except sigma 3 coincidence site lattice (CSL). Intra-grain defects in 1 μm wide strips were significantly reduced by suppressing the agglomeration of molten Si with low temperature condition around melting point of crystalline Si. Thin film transistors (TFTs), using optimized ZMR condition by scanning speed of 1500 mm/s demonstrated extremely high performance with field effect mobility (uFE) of 443 cm2/Vs and swing factor (S) of 210 mV/dec. Part of this work was supported by the Research Institute for Nanodevice and Bio Systems (RNBS), Hiroshima University.

  14. Low pressure hand made PVD system for high crystalline metal thin film preparation in micro-nanometer scale

    NASA Astrophysics Data System (ADS)

    Rosikhin, Ahmad; Hidayat, Aulia Fikri; Marimpul, Rinaldo; Syuhada, Ibnu; Winata, Toto

    2016-02-01

    High crystalline metal thin film preparation in application both for catalyst substrate or electrode in any electronic devices always to be considered in material functional material research and development. As a substrate catalyst, this metal take a role as guidance for material growth in order to resulted in proper surface structure although at the end it will be removed via etching process. Meanwhile as electrodes, it will dragging charges to be collected inside. This brief discussion will elaborate general fundamental principle of physical vapor deposition (PVD) system for metal thin film preparation in micro-nanometer scale. The influence of thermodynamic parameters and metal characteristic such as melting point and particle size will be elucidated. Physical description of deposition process in the chamber can be simplified by schematic evaporation phenomena which is supported by experimental measurement such as SEM and XRD.

  15. Low pressure hand made PVD system for high crystalline metal thin film preparation in micro-nanometer scale

    SciTech Connect

    Rosikhin, Ahmad Hidayat, Aulia Fikri; Marimpul, Rinaldo; Syuhada, Ibnu; Winata, Toto

    2016-02-08

    High crystalline metal thin film preparation in application both for catalyst substrate or electrode in any electronic devices always to be considered in material functional material research and development. As a substrate catalyst, this metal take a role as guidance for material growth in order to resulted in proper surface structure although at the end it will be removed via etching process. Meanwhile as electrodes, it will dragging charges to be collected inside. This brief discussion will elaborate general fundamental principle of physical vapor deposition (PVD) system for metal thin film preparation in micro-nanometer scale. The influence of thermodynamic parameters and metal characteristic such as melting point and particle size will be elucidated. Physical description of deposition process in the chamber can be simplified by schematic evaporation phenomena which is supported by experimental measurement such as SEM and XRD.

  16. Selective epitaxial silicon growth in the 650-1100 °C range in a reduced pressure chemical vapor deposition reactor using dichlorosilane

    NASA Astrophysics Data System (ADS)

    Regolini, J. L.; Bensahel, D.; Scheid, E.; Mercier, J.

    1989-02-01

    Selective epitaxial silicon layers have been grown in a reduced pressure (<2 Torr) reactor in the 650-1100 °C temperature range using only dichlorosilane (DCS) gas diluted in hydrogen. The growth rate plotted in Arrhenius coordinates (log G vs 1/T) shows an activation energy of 59 kcal/mol in the 650-800 °C range. A comparison is made between the DCS system and our previous results concerning the SiH4/HCl/H2 system.

  17. Performance enhancement for the triboelectric energy harvester by using interfacial micro-dome array structures

    NASA Astrophysics Data System (ADS)

    Liao, Ming-Han; Huang, Hong-Yi; Chuang, Chih-Chieh

    2017-04-01

    Interfacial micro-dome array structures are proposed to enhance the performance of triboelectric energy harvester (TEH) devices. With the designed process flow for the demonstration of the interfacial micro-dome array structures, open-circuit voltage (Voc) is found to be improved about 2 times compared with the previously reported micro-pyramid array TEH device. The modeling, simulation, visualization experiment, and electrical measurements are conducted and analyzed to clarify the impact of the different interfacial microarray structures in the TEH devices. We conclude that the proposed micro-dome array TEH device indeed can result in the best output power density, Voc, pressure sensing sensitivity, and pressure sensing range.

  18. The dependence on pressure of the plastic flow of rocksalt in the temperature range 25-250° C: implications for the rate controlling mechanism

    NASA Astrophysics Data System (ADS)

    Muhammad, Nawaz; Spiers, Chris; De Bresser, Hans; Peach, Colin

    2014-05-01

    Despite the large body of data that already exists, the question what microphysical mechanisms govern plastic flow of natural rocksalt at in situ conditions has not yet been answered to full satisfaction. In particular, the exact mechanism controlling dislocation motion at relatively low temperature is still insufficiently understood. As a result, uncertainties exist regarding the appropriate mechanism-based flow-law for low temperature, hampering reliable extrapolation of lab creep data to in situ strain rates. Such extrapolation is required for the modelling of the long term behaviour of salt for geomechanical purposes (e.g. subsidence prognosis). Several dislocation models have been proposed to control plastic flow of rocksalt, such as dislocation climb, cross-slip and (impurity-controlled) glide, but none of these have been rigorously verified. One way to test which model is appropriate is by investigating the pressure dependence of flow of rocksalt. Dislocation glide is expected to be hardly affected by pressure, cross slip (controlled by constriction of partial dislocations) will become easier with increasing pressure, and dislocation climb will become more difficult. We performed conventional axi-symmetric compression tests on synthetic polycrystalline salt samples with an average grain size of 300 μm. The samples were dry, in order to eliminate the possible influence of pressure solution creep. The experiments were carried out at temperatures in the range 25-250° C, i.e. 0.28-0.48Tm, and at pressure ranging 50-600 MPa, which is a range not previously covered for polycrystalline rocksalt. Argon gas was used as the pressure medium. With confining pressure increasing from 50 to 600 MPa, the rocksalt remained of the same strength at RT, but became about 60% stronger at 125oC and about 80% stronger at 250oC at strain rate 10-6 s-1 (at 15% strain). Using a conventional (Dorn-type) power law to describe the mechanical behaviour, stress exponents (n) were found

  19. High-Q Wafer Level Package Based on Modified Tri-Layer Anodic Bonding and High Performance Getter and Its Evaluation for Micro Resonant Pressure Sensor

    PubMed Central

    Wang, Liying; Du, Xiaohui; Wang, Lingyun; Xu, Zhanhao; Zhang, Chenying; Gu, Dandan

    2017-01-01

    In order to achieve and maintain a high quality factor (high-Q) for the micro resonant pressure sensor, this paper presents a new wafer level package by adopting cross-layer anodic bonding technique of the glass/silicon/silica (GSS) stackable structure and integrated Ti getter. A double-layer structure similar to a silicon-on-insulator (SOI) wafer is formed after the resonant layer and the pressure-sensitive layer are bonded by silicon direct bonding (SDB). In order to form good bonding quality between the pressure-sensitive layer and the glass cap layer, the cross-layer anodic bonding technique is proposed for vacuum package by sputtering Aluminum (Al) on the combination wafer of the pressure-sensitive layer and the resonant layer to achieve electrical interconnection. The model and the bonding effect of this technique are discussed. In addition, in order to enhance the performance of titanium (Ti) getter, the prepared and activation parameters of Ti getter under different sputtering conditions are optimized and discussed. Based on the optimized results, the Ti getter (thickness of 300 nm to 500 nm) is also deposited on the inside of the glass groove by magnetron sputtering to maintain stable quality factor (Q). The Q test of the built testing system shows that the number of resonators with a Q value of more than 10,000 accounts for more than 73% of the total. With an interval of 1.5 years, the Q value of the samples remains almost constant. It proves the proposed cross-layer anodic bonding and getter technique can realize high-Q resonant structure for long-term stable operation. PMID:28300752

  20. High-Q Wafer Level Package Based on Modified Tri-Layer Anodic Bonding and High Performance Getter and Its Evaluation for Micro Resonant Pressure Sensor.

    PubMed

    Wang, Liying; Du, Xiaohui; Wang, Lingyun; Xu, Zhanhao; Zhang, Chenying; Gu, Dandan

    2017-03-16

    In order to achieve and maintain a high quality factor (high-Q) for the micro resonant pressure sensor, this paper presents a new wafer level package by adopting cross-layer anodic bonding technique of the glass/silicon/silica (GSS) stackable structure and integrated Ti getter. A double-layer structure similar to a silicon-on-insulator (SOI) wafer is formed after the resonant layer and the pressure-sensitive layer are bonded by silicon direct bonding (SDB). In order to form good bonding quality between the pressure-sensitive layer and the glass cap layer, the cross-layer anodic bonding technique is proposed for vacuum package by sputtering Aluminum (Al) on the combination wafer of the pressure-sensitive layer and the resonant layer to achieve electrical interconnection. The model and the bonding effect of this technique are discussed. In addition, in order to enhance the performance of titanium (Ti) getter, the prepared and activation parameters of Ti getter under different sputtering conditions are optimized and discussed. Based on the optimized results, the Ti getter (thickness of 300 nm to 500 nm) is also deposited on the inside of the glass groove by magnetron sputtering to maintain stable quality factor (Q). The Q test of the built testing system shows that the number of resonators with a Q value of more than 10,000 accounts for more than 73% of the total. With an interval of 1.5 years, the Q value of the samples remains almost constant. It proves the proposed cross-layer anodic bonding and getter technique can realize high-Q resonant structure for long-term stable operation.

  1. Theoretical analysis and simulation of obstructed breakup of micro-droplet in T-junction under an asymmetric pressure difference

    NASA Astrophysics Data System (ADS)

    Fu, Yuhang; Bai, Lin; Jin, Yong; Cheng, Yi

    2017-03-01

    Asymmetric droplet breakup under a pressure difference at two outlets of a T-junction is investigated theoretically and numerically in this study. An accurate analysis of the evolution of droplet dynamics during the obstructed breakup process has been conducted. Meanwhile, the lattice Boltzmann method based on color gradient model is employed to simulate the system with the verification of the theoretical results. It is demonstrated that the Zou-He boundary setting at each outlet is advantageous for modifying the pressure drop of the two branches of T-junction. The results reveal that asymmetric breakup of the unequally sized droplets follows two steps, namely, the filling stage and the breakup stage. Then a universal parameter is proposed to describe the asymmetric condition of droplet breakup in T-junction, which plays a key role to characterize the temporal evolution of volume ratio and the droplet length of formed smaller droplets.

  2. The adsorption of lead(II) ions by dynamic high pressure micro-fluidization treated insoluble soybean dietary fiber.

    PubMed

    Wang, Hui; Huang, Tao; Tu, Zong-Cai; Ruan, Chuan-Ying; Lin, Derong

    2016-06-01

    Insoluble dietary fiber from soybean residue (SIDF) was treated with dynamic high-pressure microfluidization (DHPM) and used as adsorbent for Pb(II) ion. The effects of pressure on the Pb(II) adsorption capacity, primary cilia structure and surface topography of SIDF were determined using a gastrointestinal simulated model in vitro. SIDF (at pH 7.0) showed maximum binding capacity (261.42 ± 2.77 μmol/g), which was about 1.13 times higher than that of untreated sample (233.47 ± 1.84 μmol/g), when pressure reached 80 MPa. However, the net adsorption value of SIDF in a simulated small intestine (~ 9 μmol/g) was significantly lower than that in the stomach (~ 48 μmol/g), because of the competitive adsorption of Pb(2+) by pancreatin, cholate and several enzymes in the small intestine. In addition, the adsorption capacity of SIDF exhibited good linear relationship with the physicochemical properties of total negative charges, and the adsorption behavior presumably occurred on the surface area of granules fiber.

  3. Experimental study of the dehydration reactions gypsum-bassanite and bassanite-anhydrite at high pressure: Indication of anomalous behavior of H2O at high pressure in the temperature range of 50-300 °C

    NASA Astrophysics Data System (ADS)

    Mirwald, Peter W.

    2008-02-01

    The system CaSO4-H2O, characterized by the three dehydration reactions gypsum-anhydrite, gypsum-bassanite, and bassanite-anhydrite, was reexamined by in situ differential pressure analysis in the temperature range of 60-350°C up to 3.5GPa pressure. The investigation revealed a fine structure in the dehydration boundaries of gypsum-bassanite and bassanite-anhydrite, each characterized by three inflections at 0.9-1.0, 1.9-2.0, and 2.6-28GPa. In addition, the phase transition of anhydrite high pressure anhydrite (monazite structure) was established for the first time at high P-T conditions intersecting the bassanite-anhydrite dehydration boundary at 2.15GPa /250°C. Furthermore, the triple point gypsum-bassanite-anhydrite was redetermined with 235MPa/80.5°C. The evaluation of the gypsum-bassanite dehydration boundary with respect to the volume and entropy change of the reaction, ΔVreact and ΔSreact, by means of the Clausius-Clapeyron relation yields for the entropy parameter an unusually large increase over the range of the noted inflections. This is interpreted as anomalous entropy behavior of H2O related presumably to a dramatic increase in fluctuations of the hydrogen network of the liquid leading possibly into a new structural state. The effect is strongly related to the three noted pressure levels of 0.9-1.0, 1.9-2.0, and 2.6-28GPa. In a synopsis of data including also a previous high pressure study in the temperature range between 0 and 80°C, a tentative P-T diagram of H2O is proposed.

  4. Effect of Dry Needling on Spasticity, Shoulder Range of Motion, and Pressure Pain Sensitivity in Patients With Stroke: A Crossover Study.

    PubMed

    Mendigutia-Gómez, Ana; Martín-Hernández, Carolina; Salom-Moreno, Jaime; Fernández-de-Las-Peñas, César

    2016-06-01

    The purpose of this study was to determine the effects of the inclusion of deep dry needling (DDN) in spastic shoulder muscles into a rehabilitation program on spasticity, pressure pain sensitivity, and shoulder range of motion in subjects who had experienced a stroke. A controlled, repeated-measures, crossover, double-blinded, randomized trial was conducted. Twenty patients who have had a stroke were randomly assigned to receive rehabilitation alone or rehabilitation combined with DDN over the upper trapezius, infraspinatus, subscapularis, and pectoralis mayor muscles on the spastic shoulder. Subjects received both interventions separated at least 15 days apart. Each intervention was applied once per week over 3 weeks. Spasticity (Modified Ashworth Scale), pressure pain thresholds over the deltoid and infraspinatus muscles and C5-C6 zygapophyseal joint, and shoulder range of motion were collected 1 week before and 1 week after each intervention by a blinded assessor. Reduction in spasticity was similar after both conditions for the upper trapezius, pectoralis major, and subscapularis muscles. A greater number of individuals receiving DDN exhibited decreased spasticity within the infraspinatus muscle. The analysis of covariance showed that all pressure pain thresholds, shoulder abduction, and external rotation of the shoulder increased significantly more after DNN intervention (P < .05). Shoulder flexion showed similar changes after both conditions. Our results suggest that inclusion of DDN into a multimodal rehabilitation program was effective for decreasing localized pressure sensitivity and improving shoulder range of motion in individuals who had experienced stroke; however, we did not observe significant differences in muscle spasticity. Copyright © 2016. Published by Elsevier Inc.

  5. Special Equations of State for Methane, Argon, and Nitrogen for the Temperature Range from 270 to 350 K at Pressures up to 30 MPa

    NASA Astrophysics Data System (ADS)

    Wagner, W.; Span, R.

    1993-07-01

    In order to describe the thermodynamic behavior of methane, argon, and nitrogen in the so-called “natural-gas region,” namely, from 270 to 350 K at pressures up to 30 MPa as accurate as possible with equations of a very simple form, new equations of state for these three substances have been developed. These equations are in the form of a fundamental equation in the dimensionless Helmholtz energy; for calculating the pressure or the density, the corresponding equations explicit in pressure are also given. The residual parts of the Helmholtz function representing the behavior of the real gas contain 12 fitted coefficients for methane, 8 for argon, and 7 for nitrogen. The thermodynamic relations between the Helmholtz energy and the most important thermodynamic properties and the needed derivatives of the equations are explicitly given; to assist the user there is also a table with values for computer-program verification. The uncertainties when calculating the density ρ, the speed of sound w, the isobaric specific heat capacity c p, and the isochoric specific heat capacity c v are estimated as follows. For all three substances it is Δρ/ρ≤±0.02 % for p≤ 12 MPa and Δρ/ρ ≤ ±0.05% for higher pressures. For methane it is Δw/w≤±0.02% for p≤10 MPa and Δw/w≤+-0.1% for higher pressures; for argon it is Δw/w≲-0.1 % for p≤ 7 MPa, Δw/w≤±0.3 % for 7 < p≤30 MPa; and for nitrogen it is Δw/w≤±0.1% for p≤1.5 MPa and Δw/w±0.5% for higher pressures. For all three substances it is Δc p/ c p≤±1 % and ΔC v/ C v≤±1 % in the entire range.

  6. Discharge physics and influence of the modulation on helium DBD modes in the medium-frequency range at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Boisvert, Jean-Sébastien; Margot, Joëlle; Massines, Françoise

    2017-04-01

    In this paper the recently reported hybrid mode (a dielectric barrier discharge (DBD) excited by an electric field oscillating at about 1 MHz) is investigated using space and time-resolved imaging together with electrical measurements. In contrast with the helium low-frequency DBD, at 1.6 MHz the light emission is desynchronized with the discharge current. It rather depends on the enhanced rate of stepwise excitation resulting from the massive secondary emission occurring 0.15Ƭ after the discharge current maximum (Ƭ is the excitation wave period). The consequence of ion impacts on the dielectric surfaces is a higher gas and dielectric temperatures as compared to typical helium DBDs. The electrical behavior and the gas temperature of a pulsed dielectric-barrier discharge operated at 1.6 MHz are also described in this paper as a function of the repetition rate (varying from 1 Hz to 10 kHz). The gas temperature is reduced when repetition rates higher or equal to 10 Hz is used. This is related to the gas renewal rate of 8.3 Hz, i.e., gas residence time of 120 ms in our conditions. In addition, due to the memory effect in the gas, the gas gap voltage decreases as the repetition rate increases. However, beyond 100 Hz, the power decreases and the gas gap voltage increases again. As a consequence, for a given power density, the optimal repetition rate is 100 Hz which minimizes the gas temperature without reducing the power density. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  7. Novel fabric pressure sensors: design, fabrication, and characterization

    NASA Astrophysics Data System (ADS)

    Wang, Yangyong; Hua, Tao; Zhu, Bo; Li, Qiao; Yi, Weijing; Tao, Xiaoming

    2011-06-01

    Soft and pliable pressure sensors are essential elements in wearable electronics which have wide applications in modern daily lives. This paper presents a family of fabric pressure sensors made by sandwiching a piece of resistive fabric strain sensing element between two tooth-structured layers of soft elastomers. The pressure sensors are capable of measuring pressure from 0 to 2000 kPa, covering the whole range of human-machine interactions. A pressure sensitivity of up to 2.98 × 10 - 3 kPa - 1 was obtained. Theoretical modeling was conducted based on an energy method to predict the load-displacement relationship for various sensor configurations. By adjusting the Young's modulus of the two conversion layers, as well as the geometrical dimensions, the measurement ranges, and sensitivities of the sensors can be quantitatively determined. The sensors are being used for pressure measurements between the human body and garments, shoes, beds, and chairs.

  8. Chemistry of neutral species in the effluent of the micro atmospheric pressure plasma jet in water-helium admixture

    NASA Astrophysics Data System (ADS)

    Willems, Gert; Benedikt, Jan; von Keudell, Achim

    2016-09-01

    A thorough understanding and good control of produced neutral and charged species by cold atmospheric plasmas is essential for potential environmental and/or bio-medical applications. In this study we use the COST reference micro plasma jet (µ-APPJ), which is a radio-frequency capacitive coupled plasma source with 1 mm electrode distance, which has been operated in helium-water vapour mixture and has been studied as a potential source of hydroxyl radicals and hydrogen peroxide molecules. The water vapour concentration was up to 1.2%. Molecular Beam mass spectrometry is used as diagnostic tool. An absolute calibration of hydrogen peroxide was conducted using a double bubbler concept, because the ionization cross section for hydrogen peroxide is not available. Additionally the effluent chemistry was investigated by use of a 0D and 2D model. Absolute densities of hydrogen peroxide and hydroxyl radicals from atmospheric plasma will be presented. Their dependency on water vapour concentration in the carrier gas as well as distance to target have been investigated. The measured density is between 5E-13 cm-3 (2.4ppm) and 1.5E-14 cm-3 (7.2ppm) for both hydrogen peroxide molecules and hydroxyl radicals. The achieved results are in good agreement with other experiments.

  9. PaCO2 and alveolar dead space are more relevant than PaO2/FiO2 ratio in monitoring the respiratory response to prone position in ARDS patients: a physiological study

    PubMed Central

    2011-01-01

    Introduction Our aims in this study were to report changes in the ratio of alveolar dead space to tidal volume (VDalv/VT) in the prone position (PP) and to test whether changes in partial pressure of arterial CO2 (PaCO2) may be more relevant than changes in the ratio of partial pressure of arterial O2 to fraction of inspired O2 (PaO2/FiO2) in defining the respiratory response to PP. We also aimed to validate a recently proposed method of estimation of the physiological dead space (VDphysiol/VT) without measurement of expired CO2. Methods Thirteen patients with a PaO2/FiO2 ratio < 100 mmHg were included in the study. Plateau pressure (Pplat), positive end-expiratory pressure (PEEP), blood gas analysis and expiratory CO2 were recorded with patients in the supine position and after 3, 6, 9, 12 and 15 hours in the PP. Responders to PP were defined after 15 hours of PP either by an increase in PaO2/FiO2 ratio > 20 mmHg or by a decrease in PaCO2 > 2 mmHg. Estimated and measured VDphysiol/VT ratios were compared. Results PP induced a decrease in Pplat, PaCO2 and VDalv/VT ratio and increases in PaO2/FiO2 ratios and compliance of the respiratory system (Crs). Maximal changes were observed after six to nine hours. Changes in VDalv/VT were correlated with changes in Crs, but not with changes in PaO2/FiO2 ratios. When the response was defined by PaO2/FiO2 ratio, no significant differences in Pplat, PaCO2 or VDalv/VT alterations between responders (n = 7) and nonresponders (n = 6) were observed. When the response was defined by PaCO2, four patients were differently classified, and responders (n = 7) had a greater decrease in VDalv/VT ratio and in Pplat and a greater increase in PaO2/FiO2 ratio and in Crs than nonresponders (n = 6). Estimated VDphysiol/VT ratios significantly underestimated measured VDphysiol/VT ratios (concordance correlation coefficient 0.19 (interquartile ranges 0.091 to 0.28)), whereas changes during PP were more reliable (concordance correlation coefficient

  10. The Impact of Azilsartan Medoxomil Treatment (Capsule Formulation) at Doses Ranging From 10 to 80 mg: Significant, Rapid Reductions in Clinic Diastolic and Systolic Blood Pressure.

    PubMed

    Perez, Alfonso; Cao, Charlie

    2017-03-01

    In this phase 2, multicenter, parallel-group, double-blind, dose-ranging study, hypertensive adults (n=449) were randomized to receive one of five doses of a capsule formulation of azilsartan medoxomil (AZL-M; 5, 10, 20, 40, 80 mg), olmesartan medoxomil (OLM) 20 mg, or placebo once daily. The primary endpoint was change in trough clinic diastolic blood pressure (DBP) at week 8. AZL-M provided rapid statistically and clinically significant reductions in DBP and systolic blood pressure (SBP) vs placebo at all doses except 5 mg. Placebo-subtracted changes were greatest with the 40 mg dose (DBP, -5.7 mm Hg; SBP, -12.3 mm Hg). Clinic changes with AZL-M (all doses) were statistically indistinguishable vs OLM, although there were greater reductions with AZL-M 40 mg using 24-hour ambulatory blood pressure. Adverse event frequency was similar in the AZL-M and placebo groups. Based on these and other findings, subsequent trials investigated the commercial AZL-M tablet in the dose range of 20 to 80 mg/d. ©2016 Wiley Periodicals, Inc.

  11. Experimental Surface Pressure Data Obtained on 65 deg Delta Wing Across Reynolds Number and Mach Number Ranges. Vol. 4: Large-radius leading edge

    NASA Technical Reports Server (NTRS)

    Chu, Julio; Luckring, James M.

    1996-01-01

    An experimental wind tunnel test of a 65 deg delta wing model with interchangeable leading edges was conducted in the Langley National Transonic Facility (NTF). The objective was to investigate the effects of Reynolds and Mach numbers on slender-wing leading-edge vortex flows with four values of wing leading-edge bluntness. Experimentally obtained pressure data are presented without analysis in tabulated and graphical formats across a Reynolds number range of 6 x 10(exp 6) to 120 x 10(exp 6) at a Mach number of 0.85 and across a Mach number range of 0.4 to 0.9 at Reynolds numbers of 6 x 10(exp 6) and 60 x 10(exp 6). Normal-force and pitching-moment coefficient plots for these Reynolds number and Mach number ranges are also presented.

  12. Experimental Surface Pressure Data Obtained on 65 deg Delta Wing Across Reynolds Number and Mach Number Ranges. Vol. 3: Medium-radius leading edge

    NASA Technical Reports Server (NTRS)

    Chu, Julio; Luckring, James M.

    1996-01-01

    An experimental wind tunnel test of a 65 deg delta wing model with interchangeable leading edges was conducted in the Langley National Transonic Facility (NTF). The objective was to investigate the effects of Reynolds and Mach numbers on slender-wing leading-edge vortex flows with four values of wing leading-edge bluntness. Experimentally obtained pressure data are presented without analysis in tabulated and graphical formats across a Reynolds number range of 6 x 10(exp 6) to 120 x 10(exp 6) at a Mach number of 0.85 and across a Mach number range of 0.4 to 0.9 at Reynolds numbers of 6 x 10(exp 6), 60 x 10(exp 6), and 120 x 10(exp 6). Normal-force and pitching-moment coefficient plots for these Reynolds number and Mach number ranges are also presented.

  13. Experimental Surface Pressure Data Obtained on 65 deg Delta Wing Across Reynolds Number and Mach Number Ranges. Volume 2; Small-Radius Leading Edge

    NASA Technical Reports Server (NTRS)

    Chu, Julio; Luckring, James M.

    1996-01-01

    An experimental wind tunnel test of a 65 deg. delta wing model with interchangeable leading edges was conducted in the Langley National Transonic Facility (NTF). The objective was to investigate the effects of Reynolds and Mach numbers on slender-wing leading-edge vortex flows with four values of wing leading-edge bluntness. Experimentally obtained pressure data are presented without analysis in tabulated and graphical formats across a Reynolds number range of 6 x 10(exp 6) to 84 x 10(exp 6) at a Mach number of 0.85 and across a Mach number range of 0.4 to 0.9 at Reynolds numbers of 6 x 10(exp 6) and 60 x 10(exp 6). Normal-force and pitching-moment coefficient plots for these Reynolds number and Mach number ranges are also presented.

  14. Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations.

    PubMed

    Miller, Patrick J O

    2006-05-01

    Signal source intensity and detection range, which integrates source intensity with propagation loss, background noise and receiver hearing abilities, are important characteristics of communication signals. Apparent source levels were calculated for 819 pulsed calls and 24 whistles produced by free-ranging resident killer whales by triangulating the angles-of-arrival of sounds on two beamforming arrays towed in series. Levels in the 1-20 kHz band ranged from 131 to 168 dB re 1 microPa at 1 m, with differences in the means of different sound classes (whistles: 140.2+/-4.1 dB; variable calls: 146.6+/-6.6 dB; stereotyped calls: 152.6+/-5.9 dB), and among stereotyped call types. Repertoire diversity carried through to estimates of active space, with "long-range" stereotyped calls all containing overlapping, independently-modulated high-frequency components (mean estimated active space of 10-16 km in sea state zero) and "short-range" sounds (5-9 km) included all stereotyped calls without a high-frequency component, whistles, and variable calls. Short-range sounds are reported to be more common during social and resting behaviors, while long-range stereotyped calls predominate in dispersed travel and foraging behaviors. These results suggest that variability in sound pressure levels may reflect diverse social and ecological functions of the acoustic repertoire of killer whales.

  15. Micro-Mechanical Response of an Al-Mg Hybrid System Synthesized by High-Pressure Torsion.

    PubMed

    Kawasaki, Megumi; Jang, Jae-Il

    2017-05-30

    This paper summarizes recent efforts to evaluate the potential for the formation of a metal matrix nanocomposite (MMNC) by processing two commercial bulk metals of aluminum and magnesium alloy through high-pressure torsion (HPT) at room temperature. After significant evolutions in microstructures, successful fabrication of an Al-Mg hybrid system was demonstrated by observing unique microstructures consisting of a multi-layered structure and MMNC. Moreover, the evolution of small-scale mechanical properties was examined through the novel technique of nanoindentation and the improvement in plasticity was estimated by calculating the strain rate sensitivity of the Al-Mg hybrid system after HPT. The present paper demonstrates that, in addition to conventional tensile testing, the nanoindentation technique is exceptionally promising for ultrafine-grained materials processed by HPT, where the samples may have small overall dimensions and include heterogeneity in the microstructure.

  16. Micro-Mechanical Response of an Al-Mg Hybrid System Synthesized by High-Pressure Torsion

    PubMed Central

    Kawasaki, Megumi; Jang, Jae-il

    2017-01-01

    This paper summarizes recent efforts to evaluate the potential for the formation of a metal matrix nanocomposite (MMNC) by processing two commercial bulk metals of aluminum and magnesium alloy through high-pressure torsion (HPT) at room temperature. After significant evolutions in microstructures, successful fabrication of an Al-Mg hybrid system was demonstrated by observing unique microstructures consisting of a multi-layered structure and MMNC. Moreover, the evolution of small-scale mechanical properties was examined through the novel technique of nanoindentation and the improvement in plasticity was estimated by calculating the strain rate sensitivity of the Al-Mg hybrid system after HPT. The present paper demonstrates that, in addition to conventional tensile testing, the nanoindentation technique is exceptionally promising for ultrafine-grained materials processed by HPT, where the samples may have small overall dimensions and include heterogeneity in the microstructure. PMID:28772956

  17. Modeling and analysis of a novel combined peninsula-island structure diaphragm for ultra-low pressure sensing with high sensitivity

    NASA Astrophysics Data System (ADS)

    Xu, Tingzhong; Zhao, Libo; Jiang, Zhuangde; Xu, Yu; Zhao, Yulong

    2016-02-01

    A novel combined peninsula-island structure diaphragm has been developed with four pairs of peninsula and island structures as well as four gaps between them. When a pressure is applied to the diaphragm, the major strain energy of the diaphragm is locked in the position above each gap, which is called the stress concentration region (SCR). Also, minimal strain energy is wasted outside the SCR. Therefore, this novel diaphragm is favorable in obtaining high sensitivity for a micro-electromechanical system piezoresistive ultra-low pressure sensor. In order to optimize the diaphragm structure, the partial differential equation governing the diaphragm deflection has been given under pressure. The theoretical analysis solutions are obtained ba