Empirically observed learning rates for concentrating solar power and their responses to regime change

NASA Astrophysics Data System (ADS)

Lilliestam, Johan; Labordena, Mercè; Patt, Anthony; Pfenninger, Stefan

2017-07-01

Concentrating solar power (CSP) capacity has expanded slower than other renewable technologies and its costs are still high. Until now, there have been too few CSP projects to derive robust conclusions about its cost development. Here we present an empirical study of the cost development of all operating CSP stations and those under construction, examining the roles of capacity growth, industry continuity, and policy support design. We identify distinct CSP expansion phases, each characterized by different cost pressure in the policy regime and different industry continuity. In 2008-2011, with low cost pressure and following industry discontinuity, costs increased. In the current phase, with high cost pressure and continuous industry development, costs decreased rapidly, with learning rates exceeding 20%. Data for projects under construction suggest that this trend is continuing and accelerating. If support policies and industrial structure are sustained, we see no near-term factors that would hinder further cost decreases.

Apparatus and method for batch-wire continuous pumping

DOEpatents

Fassbender, Alexander G.

1996-01-01

The apparatus of the present invention contains at least one pressure vessel having a separator defining two chambers within each pressure vessel. The separator slideably seals the two chambers. Feedstock is placed within a second chamber adjoining the first chamber via a feedstock pump operating in a high volume low head mode. A pressurizer operates in a low volume high pressure mode to pressurize the working fluid and the feedstock in the pressure vessels to a process operating pressure. A circulating pump operates in a high volume, low head mode to circulate feedstock through the process. A fourth pump is used for moving feedstock and product at a pressure below the process operating pressure.

High hydrostatic pressure induces ERK and PI3 kinase phosphorylation in human HCS-2/8 chondrosarcoma cells.

PubMed

Kopakkala-Tani, M; Elo, M A; Sironen, R K; Helminen, H J; Lammi, M J

2004-06-01

High continuous hydrostatic pressure has been shown to affect many cellular functions within the pressurised cells, for instance, accumulation of heat shock protein 70 occurs during pressurisation. Various signal transduction pathways are likely to mediate these changes, however, at the present time our knowledge of the pathways involved is rather limited. The aim of this study was to investigate whether some of the well known transduction pathways are activated by the exposure of human chondrosarcoma cells to 15-30 MPa hydrostatic pressure. The results showed an increased presence of the active, phosphorylated forms of extracellular signal-related kinase (ERK) and phosphoinositide 3-kinase (PI3K) in cells exposed to 15 and 30 MPa continuous hydrostatic pressure, while 0.5 Hz cyclic loading had weaker effects. Inhibition of ERK-pathway with UO126 did not prevent the accumulation of heat shock protein 70. No activation of c-Jun N-terminal protein kinase (JNK) or p38 could be noticed in pressurised cells. In conclusion, we could identify at least two different signal transduction pathways that are activated under high continuous hydrostatic pressure. Accumulation of heat shock protein 70 was independent of ERK-activation.

Dynamic Behavior of Microbubbles during Long Ultrasound Tone-Burst Excitation: Mechanistic Insights into Ultrasound-Microbubble Mediated Therapeutics Using High-Speed Imaging and Cavitation Detection.

PubMed

Chen, Xucai; Wang, Jianjun; Pacella, John J; Villanueva, Flordeliza S

2016-02-01

Ultrasound (US)-microbubble (MB)-mediated therapies have been found to restore perfusion and enhance drug/gene delivery. On the presumption that MBs do not persist during long US exposure under high acoustic pressures, most schemes use short US pulses when a high US pressure is employed. However, we recently observed an enhanced thrombolytic effect using long US pulses at high acoustic pressures. Therefore, we explored the fate of MBs during long tone-burst exposures (5 ms) at various acoustic pressures and MB concentrations via direct high-speed optical observation and passive cavitation detection. MBs first underwent stable or inertial cavitation depending on the acoustic pressure and then formed gas-filled clusters that continued to oscillate, break up and form new clusters. Cavitation detection confirmed continued, albeit diminishing, acoustic activity throughout the 5-ms US excitation. These data suggest that persisting cavitation activity during long tone bursts may confer additional therapeutic effects. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Small-volume, ultrahigh-vacuum-compatible high-pressure reaction cell for combined kinetic and in situ IR spectroscopic measurements on planar model catalysts

NASA Astrophysics Data System (ADS)

Zhao, Z.; Diemant, T.; Häring, T.; Rauscher, H.; Behm, R. J.

2005-12-01

We describe the design and performance of a high-pressure reaction cell for simultaneous kinetic and in situ infrared reflection (IR) spectroscopic measurements on model catalysts at elevated pressures, between 10-3 and 103mbars, which can be operated both as batch reactor and as flow reactor with defined gas flow. The cell is attached to an ultrahigh-vacuum (UHV) system, which is used for sample preparation and also contains facilities for sample characterization. Specific for this design is the combination of a small cell volume, which allows kinetic measurements with high sensitivity under batch or continuous flow conditions, the complete isolation of the cell from the UHV part during UHV measurements, continuous temperature control during both UHV and high-pressure operation, and rapid transfer between UHV and high-pressure stage. Gas dosing is performed by a designed gas-handling system, which allows operation as flow reactor with calibrated gas flows at adjustable pressures. To study the kinetics of reactions on the model catalysts, a quadrupole mass spectrometer is connected to the high-pressure cell. IR measurements are possible in situ by polarization-modulation infrared reflection-absorption spectroscopy, which also allows measurements at elevated pressures. The performance of the setup is demonstrated by test measurements on the kinetics for CO oxidation and the CO adsorption on a Au /TiO2/Ru(0001) model catalyst film at 1-50 mbar total pressure.

Nasal continuous positive airway pressure: does bubbling improve gas exchange?

PubMed

Morley, C J; Lau, R; De Paoli, A; Davis, P G

2005-07-01

In a randomised crossover trial, 26 babies, treated with Hudson prong continuous positive airway pressure (CPAP) from a bubbling bottle, received vigorous, high amplitude, or slow bubbling for 30 minutes. Pulse oximetry, transcutaneous carbon dioxide, and respiratory rate were recorded. The bubbling rates had no effect on carbon dioxide, oxygenation, or respiratory rate.

49 CFR 195.424 - Pipe movement.

Code of Federal Regulations, 2012 CFR

2012-10-01

... operating pressure. (b) No operator may move any pipeline containing highly volatile liquids where materials... pressure of the commodity. (c) No operator may move any pipeline containing highly volatile liquids where... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY...

49 CFR 195.424 - Pipe movement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... operating pressure. (b) No operator may move any pipeline containing highly volatile liquids where materials... pressure of the commodity. (c) No operator may move any pipeline containing highly volatile liquids where... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY...

49 CFR 195.424 - Pipe movement.

Code of Federal Regulations, 2013 CFR

2013-10-01

... operating pressure. (b) No operator may move any pipeline containing highly volatile liquids where materials... pressure of the commodity. (c) No operator may move any pipeline containing highly volatile liquids where... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY...

49 CFR 195.424 - Pipe movement.

Code of Federal Regulations, 2014 CFR

2014-10-01

... operating pressure. (b) No operator may move any pipeline containing highly volatile liquids where materials... pressure of the commodity. (c) No operator may move any pipeline containing highly volatile liquids where... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY...

Quantification of peripheral and central blood pressure variability using a time-frequency method.

PubMed

Kouchaki, Z; Butlin, M; Qasem, A; Avolio, A P

2016-08-01

Systolic blood pressure variability (BPV) is associated with cardiovascular events. As the beat-to-beat variation of blood pressure is due to interaction of several cardiovascular control systems operating with different response times, assessment of BPV by spectral analysis using the continuous measurement of arterial pressure in the finger is used to differentiate the contribution of these systems in regulating blood pressure. However, as baroreceptors are centrally located, this study considered applying a continuous aortic pressure signal estimated noninvasively from finger pressure for assessment of systolic BPV by a time-frequency method using Short Time Fourier Transform (STFT). The average ratio of low frequency and high frequency power band (LF PB /HF PB ) was computed by time-frequency decomposition of peripheral systolic pressure (pSBP) and derived central aortic systolic blood pressure (cSBP) in 30 healthy subjects (25-62 years) as a marker of balance between cardiovascular control systems contributing in low and high frequency blood pressure variability. The results showed that the BPV assessed from finger pressure (pBPV) overestimated the BPV values compared to that assessed from central aortic pressure (cBPV) for identical cardiac cycles (P<;0.001), with the overestimation being greater at higher power.

In situ high-pressure measurement of crystal solubility by using neutron diffraction

NASA Astrophysics Data System (ADS)

Chen, Ji; Hu, Qiwei; Fang, Leiming; He, Duanwei; Chen, Xiping; Xie, Lei; Chen, Bo; Li, Xin; Ni, Xiaolin; Fan, Cong; Liang, Akun

2018-05-01

Crystal solubility is one of the most important thermo-physical properties and plays a key role in industrial applications, fundamental science, and geoscientific research. However, high-pressure in situ measurements of crystal solubility remain very challenging. Here, we present a method involving high-pressure neutron diffraction for making high-precision in situ measurements of crystal solubility as a function of pressure over a wide range of pressures. For these experiments, we designed a piston-cylinder cell with a large chamber volume for high-pressure neutron diffraction. The solution pressures are continuously monitored in situ based on the equation of state of the sample crystal. The solubility at a high pressure can be obtained by applying a Rietveld quantitative multiphase analysis. To evaluate the proposed method, we measured the high-pressure solubility of NaCl in water up to 610 MPa. At a low pressure, the results are consistent with the previous results measured ex situ. At a higher pressure, more reliable data could be provided by using an in situ high-pressure neutron diffraction method.

Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model.

PubMed

Yoshida, Takeshi; Engelberts, Doreen; Otulakowski, Gail; Katira, Bhushan; Post, Martin; Ferguson, Niall D; Brochard, Laurent; Amato, Marcelo B P; Kavanagh, Brian P

2018-04-27

In supine patients with acute respiratory distress syndrome, the lung typically partitions into regions of dorsal atelectasis and ventral aeration ("baby lung"). Positive airway pressure is often used to recruit atelectasis, but often overinflates ventral (already aerated) regions. A novel approach to selective recruitment of dorsal atelectasis is by "continuous negative abdominal pressure." A randomized laboratory study was performed in anesthetized pigs. Lung injury was induced by surfactant lavage followed by 1 h of injurious mechanical ventilation. Randomization (five pigs in each group) was to positive end-expiratory pressure (PEEP) alone or PEEP with continuous negative abdominal pressure (-5 cm H2O via a plexiglass chamber enclosing hindlimbs, pelvis, and abdomen), followed by 4 h of injurious ventilation (high tidal volume, 20 ml/kg; low expiratory transpulmonary pressure, -3 cm H2O). The level of PEEP at the start was ≈7 (vs. ≈3) cm H2O in the PEEP (vs. PEEP plus continuous negative abdominal pressure) groups. Esophageal pressure, hemodynamics, and electrical impedance tomography were recorded, and injury determined by lung wet/dry weight ratio and interleukin-6 expression. All animals survived, but cardiac output was decreased in the PEEP group. Addition of continuous negative abdominal pressure to PEEP resulted in greater oxygenation (PaO2/fractional inspired oxygen 316 ± 134 vs. 80 ± 24 mmHg at 4 h, P = 0.005), compliance (14.2 ± 3.0 vs. 10.3 ± 2.2 ml/cm H2O, P = 0.049), and homogeneity of ventilation, with less pulmonary edema (≈10% less) and interleukin-6 expression (≈30% less). Continuous negative abdominal pressure added to PEEP reduces ventilator-induced lung injury in a pig model compared with PEEP alone, despite targeting identical expiratory transpulmonary pressure.

Planar near-nozzle velocity measurements during a single high-pressure fuel injection

NASA Astrophysics Data System (ADS)

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

2015-09-01

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

High pressure high temperature devitrification of Fe78B13Si9 metallic glass with simultaneous x-ray structural characterization

NASA Astrophysics Data System (ADS)

Stemshorn, Andrew K.; Vohra, Yogesh K.; Smith, Spencer J.

2018-06-01

Changes in bulk crystallization behavior following devitrification at high pressure are investigated for a Fe78B13Si9 composition metallic glass using in-situ energy dispersive x-ray powder diffraction. Crystallization with time was evaluated for a series of measurements to a maximum pressure of 5.63 ± 0.15 GPa for the Fe78B13Si9 glass. Pressure was found to strongly affect onset bulk crystallization temperature Tx. Crystallization at each pressure was found to progress in two stages. In the first stage, α-Fe precipitates and in the second Fe2B forms while α-Fe continues to crystallize. Complementary high pressure room temperature studies were conducted.

Modeling water partition in composite gels of BSA with gelatin following high pressure treatment.

PubMed

Semasaka, Carine; Mhaske, Pranita; Buckow, Roman; Kasapis, Stefan

2018-11-01

Changes in the structural properties of hydrogels made with gelatin and bovine serum albumin mixtures were recorded following exposure to high pressure at 300 MPa for 15 min at 10 and 80 °C. Dynamic oscillation, SEM, FTIR and blending law modelling were utilised to rationalise results. Pressurization at the low temperature end yielded continuous gelatin networks supporting discontinuous BSA inclusions, whereas an inverted dispersion was formed at the high temperature end with the continuous BSA network suspending the discontinuous gelatin inclusions. Lewis and Nielsen equations followed the mechanical properties of the composites thus arguing that solvent partition between the two phases was always in favour of the polymer forming the continuous network. As far as we are aware, this is the first attempt to elucidate the solvent partition in pressurised hydrogel composites using blending law theory. Outcomes were contrasted with earlier work where binary mixtures were subjected only to thermal treatment. Copyright © 2018. Published by Elsevier Ltd.

BreathSens: A Continuous On-Bed Respiratory Monitoring System With Torso Localization Using an Unobtrusive Pressure Sensing Array.

PubMed

Liu, Jason J; Huang, Ming-Chun; Xu, Wenyao; Zhang, Xiaoyi; Stevens, Luke; Alshurafa, Nabil; Sarrafzadeh, Majid

2015-09-01

The ability to continuously monitor respiration rates of patients in homecare or in clinics is an important goal. Past research showed that monitoring patient breathing can lower the associated mortality rates for long-term bedridden patients. Nowadays, in-bed sensors consisting of pressure sensitive arrays are unobtrusive and are suitable for deployment in a wide range of settings. Such systems aim to extract respiratory signals from time-series pressure sequences. However, variance of movements, such as unpredictable extremities activities, affect the quality of the extracted respiratory signals. BreathSens, a high-density pressure sensing system made of e-Textile, profiles the underbody pressure distribution and localizes torso area based on the high-resolution pressure images. With a robust bodyparts localization algorithm, respiratory signals extracted from the localized torso area are insensitive to arbitrary extremities movements. In a study of 12 subjects, BreathSens demonstrated its respiratory monitoring capability with variations of sleep postures, locations, and commonly tilted clinical bed conditions.

High temperature pressure coupled ultrasonic waveguide

DOEpatents

Caines, Michael J.

1983-01-01

A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

High-temperature pressure-coupled ultrasonic waveguide

DOEpatents

Caines, M.J.

1981-02-11

A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

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%.

A Continuous Culture System for Assessing Microbial Activities in the Piezosphere

PubMed Central

Pérez-Rodríguez, Ileana

2015-01-01

Continuous culture under elevated pressures is an important technique for expanding the exploration of microbial growth and survival in extreme environments associated with the deep biosphere. Here we present a benchtop stirred continuous culture bioreactor capable of withstanding temperatures ranging from 25 to 120°C and pressures as high as 69 MPa. The system is configured to allow the employment of media enriched in dissolved gases, under oxic or anoxic conditions, while permitting periodic sampling of the incubated organisms with minimal physical/chemical disturbance inside the reactor. In a pilot experiment, the fermentative growth of the thermopiezophilic bacterium Marinitoga piezophila was investigated continuously for 382 h at 65°C and at pressures ranging from 0.1 to 40 MPa while the medium flow rate was varied from 2 to 0.025 ml/min. The enhanced growth observed at 30 and 40 MPa and 0.025 ml/min supports the pressure preferences of M. piezophila when grown fermentatively. This assay successfully demonstrates the capabilities of the bioreactor for continuous culturing at a variety of dilution rates, pressures, and temperatures. We anticipate that this technology will accelerate our understanding of the physiological and metabolic status of microorganisms under temperature, pressure, and energy regimes resembling those of the Earth's piezosphere. PMID:26209666

High phosphate diet increases arterial blood pressure via a parathyroid hormone mediated increase of renin.

PubMed

Bozic, Milica; Panizo, Sara; Sevilla, Maria A; Riera, Marta; Soler, Maria J; Pascual, Julio; Lopez, Ignacio; Freixenet, Montserrat; Fernandez, Elvira; Valdivielso, Jose M

2014-09-01

There is growing evidence suggesting that phosphate intake is associated with blood pressure levels. However, data from epidemiological studies show inconsistent results. The present study was designed to evaluate the effect of high circulating phosphorus on arterial blood pressure of healthy rats and to elucidate the potential mechanism that stands behind this effect. Animals fed a high phosphate diet for 4 weeks showed an increase in blood pressure, which returned to normal values after the addition of a phosphate binder (lanthanum carbonate) to the diet. The expression of renin in the kidney was higher, alongside an increase in plasma renin activity, angiotensin II (Ang II) levels and left ventricular hypertrophy. The addition of the phosphate binder blunted the increase in renin and Ang II levels. The levels of parathyroid hormone (PTH) were also higher in animals fed a high phosphate diet, and decreased when the phosphate binder was present in the diet. However, blood P levels remained elevated. A second group of rats underwent parathyroidectomy and received a continuous infusion of physiological levels of PTH through an implanted mini-osmotic pump. Animals fed a high phosphate diet with continuous infusion of PTH did not show an increase in blood pressure, although blood P levels were elevated. Finally, unlike with verapamil, the addition of losartan to the drinking water reverted the increase in blood pressure in rats fed a high phosphate diet. The results of this study suggest that a high phosphate diet increases arterial blood pressure through an increase in renin mediated by PTH.

Initial development of a high-pressure crystal growth facility: Center director's discretionary fund

NASA Technical Reports Server (NTRS)

Szofran, F. R.; Lehoczky, S. L.; Cobb, S. D.; Gillies, D. C.

1993-01-01

A low-cost, flexible, high-pressure (600 psi) system for crystal growth and related thermophysical properties measurements was designed, assembled, and tested. The furnace system includes a magnetically coupled translation mechanism that eliminates the need for a high-pressure mechanical feedthru. The system is currently being used for continuing crystal growth experiments and thermophysical properties measurements on several material systems including Hg(1-x)Cd(x)Te, Hg(1-x)Zn(x)Te, and Hg(1-x)Zn(x)Se.

Periodontal ligament hydrostatic pressure with areas of root resorption after application of a continuous torque moment.

PubMed

Hohmann, Ansgar; Wolfram, Uwe; Geiger, Martin; Boryor, Andrew; Sander, Christian; Faltin, Rolf; Faltin, Kurt; Sander, Franz Guenter

2007-07-01

To evaluate the risk of root resorption, individual finite element models (FEMs) of extracted human maxillary first premolars were created, and the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models was simulated. A continuous lingual torque of 3 Nmm and 6 Nmm respectively was applied in vivo to the aforementioned teeth. After extraction, FEMs of these double-rooted teeth were created based on high-resolution microcomputed tomographics (micro CT, voxel size: 35 microns). This high volumetric resolution made the recognition of very small resorption lacunae possible. Scanning electron micrographs of the root surfaces were created as well. This enabled the investigation of advantages and disadvantages of the different imaging techniques from the viewpoint of the examination of root resorption. Using the FEMs, the same loading conditions as applied in vivo were simulated. The results of clinical examination and simulations were compared using the identical roots of the teeth. The regions that showed increased hydrostatic pressure (>0.0047 MPa) correlated well with the locations of root resorption for each tooth. Increased torque resulted in increased high-pressure areas and increased magnitudes of hydrostatic pressure, correlating with the experiments. If hydrostatic pressure exceeds typical human capillary blood pressure in the PDL, the risk of root resorption increases.

Portable high precision pressure transducer system

DOEpatents

Piper, Thomas C.; Morgan, John P.; Marchant, Norman J.; Bolton, Steven M.

1994-01-01

A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.

Investigation of critical burning of fuel droplets

NASA Technical Reports Server (NTRS)

Allison, C. B.; Canada, G. S.

1972-01-01

Fuel droplets were simulated by porous spheres having diameters in the range 0.63 to 1.9 cm and combustion tests were conducted at pressures up to 78 atm in a quiescent cold air environment. Measurements were made of the burning rate and liquid surface temperature during steady combustion. A high pressure flat flame burner apparatus is under development in order to allow testing of high pressure droplet burning in a combustion gas environment. Work was continued on the high pressure strand combustion characteristics of liquid fuels, with the major emphasis on hydrazine. Data was obtained on the burning rate and liquid surface temperatures at pressures in the range 7 to 500 psia. The response of a burning liquid monopropellant to imposed pressure oscillations is being investigated.

Continuous flow synthesis of ZSM-5 zeolite on the order of seconds

PubMed Central

Liu, Zhendong; Okabe, Kotatsu; Anand, Chokkalingam; Yonezawa, Yasuo; Zhu, Jie; Yamada, Hiroki; Endo, Akira; Yanaba, Yutaka; Yoshikawa, Takeshi; Ohara, Koji; Okubo, Tatsuya; Wakihara, Toru

2016-01-01

The hydrothermal synthesis of zeolites carried out in batch reactors takes a time so long (typically, on the order of days) that the crystallization of zeolites has long been believed to be very slow in nature. We herein present a synthetic process for ZSM-5, an industrially important zeolite, on the order of seconds in a continuous flow reactor using pressurized hot water as a heating medium. Direct mixing of a well-tuned precursor (90 °C) with the pressurized water preheated to extremely high temperature (370 °C) in the millimeter-sized continuous flow reactor resulted in immediate heating to high temperatures (240–300 °C); consequently, the crystallization of ZSM-5 in a seed-free system proceeded to completion within tens of or even several seconds. These results indicate that the crystallization of zeolites can complete in a period on the order of seconds. The subtle design combining a continuous flow reactor with pressurized hot water can greatly facilitate the mass production of zeolites in the future. PMID:27911823

(Ultra) High Pressure Homogenization for Continuous High Pressure Sterilization of Pumpable Foods – A Review

PubMed Central

Georget, Erika; Miller, Brittany; Callanan, Michael; Heinz, Volker; Mathys, Alexander

2014-01-01

Bacterial spores have a strong resistance to both chemical and physical hurdles and create a risk for the food industry, which has been tackled by applying high thermal intensity treatments to sterilize food. These strong thermal treatments lead to a reduction of the organoleptic and nutritional properties of food and alternatives are actively searched for. Innovative hurdles offer an alternative to inactivate bacterial spores. In particular, recent technological developments have enabled a new generation of high pressure homogenizer working at pressures up to 400 MPa and thus, opening new opportunities for high pressure sterilization of foods. In this short review, we summarize the work conducted on (ultra) high pressure homogenization (U)HPH to inactivate endospores in model and food systems. Specific attention is given to process parameters (pressure, inlet, and valve temperatures). This review gathers the current state of the art and underlines the potential of UHPH sterilization of pumpable foods while highlighting the needs for future work. PMID:25988118

High hydrostatic pressure induces pro-osteoarthritic changes in cartilage precursor cells: A transcriptome analysis.

PubMed

Montagne, Kevin; Onuma, Yasuko; Ito, Yuzuru; Aiki, Yasuhiko; Furukawa, Katsuko S; Ushida, Takashi

2017-01-01

Due to the high water content of cartilage, hydrostatic pressure is likely one of the main physical stimuli sensed by chondrocytes. Whereas, in the physiological range (0 to around 10 MPa), hydrostatic pressure exerts mostly pro-chondrogenic effects in chondrocyte models, excessive pressures have been reported to induce detrimental effects on cartilage, such as increased apoptosis and inflammation, and decreased cartilage marker expression. Though some genes modulated by high pressure have been identified, the effects of high pressure on the global gene expression pattern have still not been investigated. In this study, using microarray technology and real-time PCR validation, we analyzed the transcriptome of ATDC5 chondrocyte progenitors submitted to a continuous pressure of 25 MPa for up to 24 h. Several hundreds of genes were found to be modulated by pressure, including some not previously known to be mechano-sensitive. High pressure markedly increased the expression of stress-related genes, apoptosis-related genes and decreased that of cartilage matrix genes. Furthermore, a large set of genes involved in the progression of osteoarthritis were also induced by high pressure, suggesting that hydrostatic pressure could partly mimic in vitro some of the genetic alterations occurring in osteoarthritis.

The 8-year report on MSX thermal blanket outgassing: an inexhaustible reservoir

NASA Astrophysics Data System (ADS)

Boies, Mark T.; Green, B. David; Galica, Gary E.; Uy, O. Manuel; Benson, Richard C.; Silver, David M.; Wood, Bobby E.; Lesho, Jeffrey C.; Hall, David F.; Dyer, James S.

2004-10-01

The Midcourse Space Experiment (MSX) spacecraft has now been in orbit for over 8 years. The Total Pressure Sensor (TPS) has continually made measurements of the ambient and spacecraft induced environment since launch on April 24, 1996. The environment surrounding the satellite continues to be very dynamic. The magnitude of the solar induced pressure peaks has not decayed with time as would be expected. Even sole consideration of measured pressure versus duration of solar illumination does not illustrate long term decay. The TPS has continued to measure pressure variations of more than 2 orders of magnitude as the sun illuminates the blankets surrounding the instrument. The multi-layer thermal blankets appear to represent a large virtual source of water. The measured pressure is highly dependent upon the solar angle and the shadowing of surfaces by other structures. We will focus our attention on the results from an identical set of experiments conducted each year in July.

Adherence to Continuous Positive Airway Pressure in Existing Users: Self-Efficacy Enhances the Association between Continuous Positive Airway Pressure and Adherence

PubMed Central

Dzierzewski, Joseph M.; Wallace, Douglas M.; Wohlgemuth, William K.

2016-01-01

Study Objectives: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder associated with a myriad of sequelae. OSAHS is effectively treated with continuous positive airway pressure (CPAP) therapy. However, fewer than 50% of patients are compliant with their CPAP therapy prescriptions. The current study sought to explore an integrated, biopsychological approach to CPAP adherence among experienced CPAP users. Methods: We performed a retrospective, cross-sectional analysis of a cohort of veterans with a diagnosis of OSAHS (n = 191) who were prescribed CPAP therapy and returned for adherence download at the Miami VA Sleep Clinic. The relationships between biomedical characteristics (e.g., CPAP pressure, self-reported sleepiness, and change in sleep efficiency) and psychological factors (e.g., self-efficacy beliefs and psychological diagnoses) and objectively measured CPAP use were examined to determine whether psychological factors moderated the relationships between biomedical characteristics and CPAP adherence. Results: Hierarchical regression analyses predicting CPAP adherence (adjusting for time since CPAP prescription, age, education, prescribed CPAP pressure, daytime sleepiness, changes in sleep efficiency with CPAP, and psychiatric conditions) revealed the following: (1) CPAP self-efficacy and CPAP pressure were positively related to adherence, and (2) CPAP self-efficacy moderates the relationship between CPAP pressure and CPAP adherence. Conclusions: There was no relationship between CPAP pressure and adherence in individuals with low self-efficacy beliefs. However, for individuals with high self-efficacy beliefs, there was a significant positive relationship between CPAP pressure and adherence. Self-efficacy beliefs appear to be a prime target for focused interventions aimed at improving CPAP adherence among those individuals with higher pressure prescriptions. Citation: Dzierzewski JM, Wallace DM, Wohlgemuth WK. Adherence to continuous positive airway pressure in existing users: self-efficacy enhances the association between continuous positive airway pressure and adherence. J Clin Sleep Med 2016;12(2):169–176. PMID:26350607

Portable high precision pressure transducer system

DOEpatents

Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.

1994-04-26

A high precision pressure transducer system is described for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display. 2 figures.

Characteristics of the mach disk in the underexpanded jet in which the back pressure continuously changes with time

NASA Astrophysics Data System (ADS)

Irie, T.; Yasunobu, T.; Kashimura, H.; Setoguchi, T.

2003-05-01

When the high-pressure gas is exhausted to the vacuum chamber from the nozzle, the underexpanded supersonic jet contained with the Mach disk is generally formed. The eventual purpose of this study is to clarify the unsteady phenomenon of the underexpanded free jet when the back pressure continuously changes with time. The characteristic of the Mach disk has been clarified in consideration of the diameter and position of it by the numerical analysis in this paper. The sonic jet of the exit Mach number Me=1 is assumed and the axisymmetric conservational equation is solved by the TVD method in the numerical calculation. The diameter and position of the Mach disk differs with the results of a steady jet and the influence on the continuously changing of the back pressure is evidenced from the comparison with the case of steady supersonic jet.

High ratio recirculating gas compressor

DOEpatents

Weinbrecht, J.F.

1989-08-22

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

New developments in laser-heated diamond anvil cell with in situ synchrotron x-ray diffraction at High Pressure Collaborative Access Team

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Yue; Hrubiak, Rostislav; Rod, Eric

An overview of the in situ laser heating system at the High Pressure Collaborative Access Team, with emphasis on newly developed capabilities, is presented. Since its establishment at the beamline 16-ID-B a decade ago, laser-heated diamond anvil cell coupled with in situ synchrotron x-ray diffraction has been widely used for studying the structural properties of materials under simultaneous high pressure and high temperature conditions. Recent developments in both continuous-wave and modulated heating techniques have been focusing on resolving technical issues of the most challenging research areas. Furthermore, the new capabilities have demonstrated clear benefits and provide new opportunities in researchmore » areas including high-pressure melting, pressure-temperature-volume equations of state, chemical reaction, and time resolved studies.« less

New developments in laser-heated diamond anvil cell with in situ synchrotron x-ray diffraction at High Pressure Collaborative Access Team

DOE PAGES

Meng, Yue; Hrubiak, Rostislav; Rod, Eric; ...

2015-07-17

An overview of the in situ laser heating system at the High Pressure Collaborative Access Team, with emphasis on newly developed capabilities, is presented. Since its establishment at the beamline 16-ID-B a decade ago, laser-heated diamond anvil cell coupled with in situ synchrotron x-ray diffraction has been widely used for studying the structural properties of materials under simultaneous high pressure and high temperature conditions. Recent developments in both continuous-wave and modulated heating techniques have been focusing on resolving technical issues of the most challenging research areas. Furthermore, the new capabilities have demonstrated clear benefits and provide new opportunities in researchmore » areas including high-pressure melting, pressure-temperature-volume equations of state, chemical reaction, and time resolved studies.« less

New developments in laser-heated diamond anvil cell with in situ synchrotron x-ray diffraction at High Pressure Collaborative Access Team

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Yue; Hrubiak, Rostislav; Rod, Eric

An overview of the in situ laser heating system at the High Pressure Collaborative Access Team, with emphasis on newly developed capabilities, is presented. Since its establishment at the beamline 16-ID-B a decade ago, laser-heated diamond anvil cell coupled with in situ synchrotron x-ray diffraction has been widely used for studying the structural properties of materials under simultaneous high pressure and high temperature conditions. Recent developments in both continuous-wave and modulated heating techniques have been focusing on resolving technical issues of the most challenging research areas. The new capabilities have demonstrated clear benefits and provide new opportunities in research areasmore » including high-pressure melting, pressure-temperature-volume equations of state, chemical reaction, and time resolved studies.« less

Accuracy of continuous noninvasive arterial pressure monitoring in living-liver donors during transplantation.

PubMed

Araz, Coskun; Zeyneloglu, Pinar; Pirat, Arash; Veziroglu, Nukhet; Camkiran Firat, Aynur; Arslan, Gulnaz

2015-04-01

Hemodynamic monitoring is vital during liver transplant surgeries because distinct hemodynamic changes are expected. The continuous noninvasive arterial pressure (CNAP) monitor is a noninvasive device for continuous arterial pressure measurement by a tonometric method. This study compared continuous noninvasive arterial pressure monitoring with invasive direct arterial pressure monitoring in living-liver donors during transplant. There were 40 patients analyzed while undergoing hepatic lobectomy for liver transplant. Invasive pressure monitoring was established at the radial artery and continuous noninvasive arterial pressure monitoring using a finger sensor was recorded simultaneously from the contralateral arm. Systolic, diastolic, and mean arterial pressures from the 2 methods were compared. Correlation between the 2 methods was calculated. A total of 5433 simultaneous measurements were obtained. For systolic arterial blood pressure, 55% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.479, continuous noninvasive arterial pressure bias was -0.3 mm Hg, and limits of agreement were 32.0 mm Hg. For diastolic arterial blood pressure, 50% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.630, continuous noninvasive arterial pressure bias was -0.4 mm Hg, and limits of agreement were 21.1 mm Hg. For mean arterial blood pressure, 60% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.692, continuous noninvasive arterial pressure bias was +0.4 mm Hg, and limits of agreement were 20.8 mm Hg. The 2 monitoring techniques did not show acceptable agreement. Our results suggest that continuous noninvasive arterial pressure monitoring is not equivalent to invasive arterial pressure monitoring in donors during living-donor liver transplant.

Studies of experimental hosiery in diabetic neuropathic patients with high foot pressures.

PubMed

Veves, A; Masson, E A; Fernando, D J; Boulton, A J

1990-05-01

High plantar pressures and painless trauma are associated with the development of foot ulcers in diabetic patients. Padded hosiery has been reported to reduce plantar pressures in patients at risk of ulceration. Using the optical pedobarograph we have studied 10 patients who regularly wore experimental padded hosiery for 6 months. The hosiery continued to provide substantial and significant reduction in peak forefoot pressures at 3 months (mean reduction 15.5%, p less than 0.01) and 6 months (17.6%, p less than 0.01), although the level of reduction was less than that seen at baseline (31.3%, p less than 0.05). In addition, commercially available hosiery designed as sportswear has been tested, and compared with experimental hosiery. Although these socks (with high or medium density padding) provided significant pressure reduction versus barefoot (mean 17.4% and 10.4%, p less than 0.01), this was not as great as that seen with experimental hosiery (27%, p less than 0.05). Thus the use of socks designed to reduce pressure stress on diabetic neuropathic feet is effective, and continues to be so for a considerable period of time. Commercially available sports socks may also have a place in the management of the diabetic insensitive foot.

Means and apparatus for throttling a dry pulverized solid material pump

DOEpatents

Meyer, J. W.; Daniel, Jr, A. D.; Bonin, J. H.

1982-12-07

Method and apparatus are shown for control of continuous feeding of pulverized material to a high pressure container. A rotor is located within the high pressure container. The pulverized material is fed from a feed hopper through a stationary feed pipe to a vented spin-up zone chamber to a plurality of sprues mounted in the rotor. Control of the pressure within control nozzles downstream from the sprues adjusts the flow rate of coal through the sprues. 9 figs.

Means and apparatus for throttling a dry pulverized solid material pump

DOEpatents

Meyer, John W [Palo Alto, CA; Daniel, Jr., Arnold D.; Bonin, John H [Sunnyvale, CA

1982-01-01

Method and apparatus are shown for control of continuous feeding of pulverized material to a high pressure container. A rotor is located within the high pressure container. The pulverized material is fed from a feed hopper through a stationary feed pipe to a vented spin-up zone chamber to a plurality of sprues mounted in the rotor. Control of the pressure within control nozzles downstream from the sprues adjusts the flow rate of coal through the sprues.

Benchtop evaluation of pressure barrier insufflator and standard insufflator systems.

PubMed

Nepple, Kenneth G; Kallogjeri, Dorina; Bhayani, Sam B

2013-01-01

Previous experimental research has reported minimal differences in pressure maintenance between different versions of standard insufflators (SI). However, a recent report identified potential clinical benefits with a valveless pressure barrier insufflator (PBI). We sought to perform a benchtop objective evaluation of SI and PBI systems. A rigid box system with continuous pressure manometry was used to evaluate a PBI (Surgiquest Airseal) and two SIs (SI1 = Stryker PneumoSure High Flow Insufflator and SI2 = Storz SCB Thermoflator). Pressure maintenance of 15 mmHg was evaluated during experimental conditions of leakage from a 5 mm port site, leakage from a 12 mm port site, and continuous suction. With leakage from the 5 mm port site, the PBI maintained pressure of >13 mmHg whereas the pressures dropped moderately with the SI1 (7-13 mmHg) and SI2 insufflators (3-7 mmHg) and did not regain goal pressure until leakage was stopped. With leakage from 12 mm port site, the PBI pressure decreased to 9-11 mmHg, whereas the SI1 and SI2 lost insufflation pressures completely. The PBI maintained pressure of >11 mmHg during continuous suction while the SI1 and SI2 lost pressure entirely, and actually showed negative pressure from air suction into the rigid box system. When evaluated statistically with the mixed model repeated measures ANOVA, the SI1 and SI2 performed similarly while the PBI maintained increased pressure. In the experimental rigid box system, the PBI more successfully maintained pressure in response to leakage and suction than SIs.

Deformation twinning of a silver nanocrystal under high pressure. Supplementary materials

DOE PAGES

Huang, X. J.; Yang, W. G.; Harder, R.; ...

2015-10-20

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

Choosing an Oronasal Mask to Deliver Continuous Positive Airway Pressure May Cause More Upper Airway Obstruction or Lead to Higher Continuous Positive Airway Pressure Requirements than a Nasal Mask in Some Patients: A Case Series

PubMed Central

Ng, Justin R.; Aiyappan, Vinod; Mercer, Jeremy; Catcheside, Peter G.; Chai-Coetzer, Ching Li; McEvoy, R. Doug; Antic, Nick

2016-01-01

Study Objectives: The choice of mask interface used with continuous positive airway pressure (CPAP) therapy can affect the control of upper airway obstruction (UAO) in obstructive sleep apnea (OSA). We describe a case series of four patients with paradoxical worsening of UAO with an oronasal mask and the effect of changing to a nasal mask. Methods: We retrospectively reviewed the case histories of 4 patients and recorded patient demographics, in-laboratory and ambulatory CPAP titration data, CPAP therapy data, type of mask interface used and potential confounding factors. Results: The 4 cases (mean ± SD: age = 59 ± 16 y; BMI = 30.5 ± 4.5 kg/m2) had a high residual apnoea-hypopnea index (AHI) (43 ± 14.2 events/h) and high CPAP pressure requirements (14.9 ± 6.6 cmH2O) with an oronasal mask. Changing to a nasal mask allowed adequate control of UAO with a significant reduction in the average residual AHI (3.1 ± 1.5 events/h). In two of the four cases, it was demonstrated that control of UAO was obtained at a much lower CPAP pressure compared to the oronasal mask (Case one = 17.5 cmH2O vs 12cmH2O; Case two = 17.9 cmH2O vs 7.8 cmH2O). Other potential confounding factors were unchanged. There are various physiological observations that may explain these findings but it is uncertain which individuals are susceptible to these mechanisms. Conclusions: If patients have OSA incompletely controlled by CPAP with evidence of residual UAO and/or are requiring surprisingly high CPAP pressure to control OSA with an oronasal mask, the choice of mask should be reviewed and consideration be given to a trial of a nasal mask. Commentary: A commentary on this article appears in this issue on page 1209. Citation: Ng JR, Aiyappan V, Mercer J, Catcheside PG, Chai-Coetzer CL, McEvoy RD, Antic N. Choosing an oronasal mask to deliver continuous positive airway pressure may cause more upper airway obstruction or lead to higher continuous positive airway pressure requirements than a nasal mask in some patients: a case series. J Clin Sleep Med 2016;12(9):1227–1232. PMID:27306398

A Comparison of Approaches to Detect Deception

DTIC Science & Technology

2010-12-30

blood pressure has been demonstrated for this instrument (Fortin et al., 2006; Sackl- Pietsch , 2010). A sampling rate of 62.5 Hz is considerably...Psychophysiology, 15, 344-359. Sackl- Pietsch , E. (2010). Continuous non-invasive arterial pressure shows high accuracy in comparison to invasive intra-arterial

Mission and System Advantages of Iodine Hall Thrusters

NASA Technical Reports Server (NTRS)

Dankanich, John W.; Szabo, James; Pote, Bruce; Oleson, Steve; Kamhawi, Hani

2014-01-01

The exploration of alternative propellants for Hall thrusters continues to be of interest to the community. Investments have been made and continue for the maturation of iodine based Hall thrusters. Iodine testing has shown comparable performance to xenon. However, iodine has a higher storage density and resulting higher ?V capability for volume constrained systems. Iodine's vapor pressure is low enough to permit low-pressure storage, but high enough to minimize potential adverse spacecraft-thruster interactions. The low vapor pressure also means that iodine does not condense inside the thruster at ordinary operating temperatures. Iodine is safe, it stores at sub-atmospheric pressure, and can be stored unregulated for years on end; whether on the ground or on orbit. Iodine fills a niche for both low power (<1kW) and high power (>10kW) electric propulsion regimes. A range of missions have been evaluated for direct comparison of Iodine and Xenon options. The results show advantages of iodine Hall systems for both small and microsatellite application and for very large exploration class missions.

Spinal cord injury pressure ulcer treatment: an experience-based approach.

PubMed

Sunn, Gabriel

2014-08-01

Pressure ulcers continue to impact the lives of spinal cord injury patients severely. Pressure ulcers must be accurately staged according to National Pressure Ulcer Advisory recommendations before treatment design. The first priority in treatment of pressure ulcers is offloading. Intact skin ulcers may be treated with noncontact nonthermal low-frequency ultrasound. Superficial pressure ulcers may be treated with a combination of collagenase and foam dressings. Deeper pressure ulcers warrant negative-pressure wound therapy dressings along with biologic adjuncts to fill in wound depth. Discovery and treatment of osteomyelitis is a high priority when initially evaluating pressure ulcers. Surgical intervention must always be considered. Published by Elsevier Inc.

A Demonstration of the Continuous Phase (Second-Order) Transition of a Binary Liquid System in the Region around Its Critical Point

ERIC Educational Resources Information Center

Johnson, Michael R.

2006-01-01

In most general chemistry and introductory physical chemistry classes, critical point is defined as that temperature-pressure point on a phase diagram where the liquid-gas interface disappears, a phenomenon that generally occurs at relatively high temperatures or high pressures. Two examples are: water, with a critical point at 647 K (critical…

Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa

NASA Astrophysics Data System (ADS)

Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling

2017-12-01

We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy--a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ˜60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics.

Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa

PubMed Central

Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling

2017-01-01

We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy––a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ∼60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics. PMID:29183981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolstad, J.W.; Haarman, R.A.

The results of two transients involving the loss of a steam generator in a single-pass, steam generator, pressurized water reactor have been analyzed using a state-of-the-art, thermal-hydraulic computer code. Computed results include the formation of a steam bubble in the core while the pressurizer is solid. Calculations show that continued injection of high pressure water would have stopped the scenario. These are similar to the happenings at Three Mile Island.

Pressure-tight closure for thermoelements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1937-06-14

The thermoelements were arranged in a pressure-tight housing for measuring temperatures on the inside of high-pressure hydrogenation equipment. Should the housing ever leak due to failure of the material or the grinding action of the high sand content of the coal paste, the stall was liable to be set on fire. If, in an installation protected in this manner, an element housing should leak, the pressure tight closure at one end of the housing prevented an escape of the gas and product and the stall could continue to run without danger. The final form of this closure was discussed inmore » detail in this report. In the development of this closure, particular value was attached to a compact construction. In the sealing for a 30-mm high pressure tube, four steel and four constantan wires were insulated and arranged pressure-tight. Each of the three fillers had a different purpose. The hard-rubber insert took the surface pressure, the rubber stopper provided a seal and the cast gypsum provided protection against heat should hot gas or product reach the closure in case of a leaky housing. Two drawings were given showing the thermoelement-closure, and the final form of the closure. The report discussed methods of evacuating from the thermohousings any accumulations of condensed water, which could damage insulation, or hydrogen, which continually diffused in small amounts during operation and which could attack the iron elements of the thermocouples. The pressure-tight closures for thermoelements had been successful at preventing fires due to leakage for more than nine months of operation. 2 sketches.« less

Continuous Steelmaking Directly from Ore

NASA Astrophysics Data System (ADS)

Warner, Noel A.

2014-12-01

In-line continuous processing of high-grade hematite ore (crushed ore or fines) with a pure hydrogen reductant is assessed. An appraisal is made of the rate controlling mechanisms involved in the reduction of a pure layer of molten wustite being transported by floating on a molten carrier iron carbon-free medium at temperatures just in excess of the iron melting point. Published research clearly indicates that under these conditions the kinetics are principally controlled by molecular gaseous diffusion. Thus, the rate is essentially not influenced by total gas pressure above 1 atmosphere. Accordingly, on safety grounds it is recommended that high pressure should not be used for hydrogen steelmaking in the future, but the operation should be conducted close to atmospheric pressure with low pressure steam encapsulation of the plant items involved. Using hydrogen as the reductant means that sub-surface nucleation of CO bubbles cannot disrupt continuous processing. The operation is then no different to processing a normal liquid phase. The off-gases from the reduction zone of a melt circulation loop are super-clean and only contaminated with iron vapor. Accordingly, the best available technology becomes available for energy conservation without risk of non-fusible solids deposition. The net result is that the energy requirements are expected to be superior to other potential processes.

Hybrid Tank Technology

NASA Technical Reports Server (NTRS)

2004-01-01

Researchers have accomplished great advances in pressure vessel technology by applying high-performance composite materials as an over-wrap to metal-lined pressure vessels. These composite over-wrapped pressure vessels (COPVs) are used in many areas, from air tanks for firefighters and compressed natural gas tanks for automobiles, to pressurant tanks for aerospace launch vehicles and propellant tanks for satellites and deep-space exploration vehicles. NASA and commercial industry are continually striving to find new ways to make high-performance pressure vessels safer and more reliable. While COPVs are much lighter than all-metal pressure vessels, the composite material, typically graphite fibers with an epoxy matrix resin, is vulnerable to impact damage. Carbon fiber is most frequently used for the high-performance COPV applications because of its high strength-to-weight characteristics. Other fibers have been used, but with limitations. For example, fiberglass is inexpensive but much heavier than carbon. Aramid fibers are impact resistant but have less strength than carbon and their performance tends to deteriorate.

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

NASA Astrophysics Data System (ADS)

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

2015-09-01

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

Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

NASA Technical Reports Server (NTRS)

Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

2005-01-01

A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

Effect of high pressure on the electrical resistivity of Ge-Te-In glasses

NASA Astrophysics Data System (ADS)

Prasad, K. N. N.; Varma, G. Sreevidya; Rukmani, K.; Asokan, S.

2015-06-01

The variation in the electrical resistivity of the chalcogenide glasses Ge15Te85-xInx has been studied as a function of high pressure for pressures up to 8.5GPa. All the samples studied undergo a semi-conductor to metallic transition in a continuous manner at pressures between 1.5-2.5GPa. The transition pressure at which the samples turn metallic increases with increase in percentage of Indium. This increase is a direct consequence of the increase in network rigidity with the addition of Indium. At a constant pressure of 0.5GPa, the normalized resistivity shows some signature of the existence of the intermediate phase. Samples recovered after a pressure cycle remain amorphous suggesting that the semi-conductor to metallic transition arises from a reduction of the band gap due to pressure or the movement of the Fermi level into the conduction or valence band.

Pressure-induced superconductivity of arsenic: Evidence for a structural phase transition

NASA Astrophysics Data System (ADS)

Kawamura, H.; Wittig, J.

1985-12-01

The group VB elements P, As, Sb and Bi are normally nonsuperconductors since they are either semiconductors or semimetals at ambient pressure. Under high pressure all of them are turned into superconductors. We have investigated the pressure dependence of Tc for As up to a pressure of 28 GPa quantitatively for the first time. Employing a 3He/ 4He dilution refrigetor we have discovered that Tc increases monotonously and steeply with pressure in the A7-rhombohedral phase from below 0.05 K at 10 GPa to a pronounced maximum at approximately 24 GPa with Tc, max2.7 K. Our results are in strong disagreement with a previous publication. In addition, a faint resistance anomaly is observed in the same pressure range. It is concluded that both phenomena point to the occurence of a structural phase transition in agreement with an unpublished X-ray investigation by another group of authors. The continuous rise of Tc with pressure in the A7 phase is so far a rather rare phenomenon among the B-group elements. Interestingly enough, quite similar behavior has also recently been reported for the A7 phases of P and Sb. We suggest that this unusual feature is related to a pressure-induced phonon softening in connection with a gradual weakening of the covalent bonds. The effect is believed to stand in close connection with the continuous reduction of the rhombohedral distortion of the crystal lattice towards simple cubic with increasing pressure. An interesting prediction for the shape of the melting curve of As at very high pressure can be made.

Microbial activity at gigapascal pressures.

PubMed

Sharma, Anurag; Scott, James H; Cody, George D; Fogel, Marilyn L; Hazen, Robert M; Hemley, Russell J; Huntress, Wesley T

2002-02-22

We observed physiological and metabolic activity of Shewanella oneidensis strain MR1 and Escherichia coli strain MG1655 at pressures of 68 to 1680 megapascals (MPa) in diamond anvil cells. We measured biological formate oxidation at high pressures (68 to 1060 MPa). At pressures of 1200 to 1600 MPa, living bacteria resided in fluid inclusions in ice-VI crystals and continued to be viable upon subsequent release to ambient pressures (0.1 MPa). Evidence of microbial viability and activity at these extreme pressures expands by an order of magnitude the range of conditions representing the habitable zone in the solar system.

Kinetic extruder - a dry pulverized solid material pump

DOEpatents

Meyer, John W [Palo Alto, CA; Bonin, John H [Sunnyvale, CA; Daniel, Jr., Arnold D.

1983-01-01

Method and apparatus are shown for the continuous feeding of pulverized material to a high pressure container. A rotor is located within the high pressure container. The pulverized material is fed from a feed hopper through a stationary feed pipe to a vented spin-up chamber to a plurality of two-stage sprues mounted in the rotor. Control nozzles downstream from the sprues meter the flow of coal through the sprues.

Effects of a continuous lateral turning device on pressure relief.

PubMed

Do, Nam Ho; Kim, Deog Young; Kim, Jung-Hoon; Choi, Jong Hyun; Joo, So Young; Kang, Na Kyung; Baek, Yoon Su

2016-01-01

[Purpose] The purpose of this study was to examine the pressure-relieving effects of a continuous lateral turning device on common pressure ulcer sites. [Subjects] Twenty-four healthy adults participated. [Methods] The design of our continuous lateral turning device was motivated by the need for an adequate pressure-relieving device for immobile and/or elderly people. The procedure of manual repositioning is embodied in our continuous lateral turning device. The interface pressure and time were measured, and comfort grade was evaluated during sessions of continuous lateral turning at 0°, 15°, 30°, and 45°. We quantified the pressure-relieving effect using peak pressure, mean pressure, and pressure time integration. [Results] Participants demonstrated pressure time integration values below the pressure-time threshold at 15°, 30°, and 45° at all the common pressure ulcer sites. Moreover, the most effective angles for pressure relief at the common pressure ulcer sites were 30° at the occiput, 15° at the left scapula, 45° at the right scapula, 45° at the sacrum, 15° at the right heel, and 30° at the left heel. However, angles greater than 30° induced discomfort. [Conclusion] Continuous lateral turning with our specially designed device effectively relieved the pressure of targeted sites. Moreover, the suggested angles of continuous lateral turning can be used to relieve pressure at targeted sites.

Dietary salt loading increases nitric oxide synthesis in transgenic mice overexpressing sodium-proton exchanger.

PubMed

Kiraku, J; Nakamura, T; Sugiyama, T; Takahashi, N; Kuro-o, M; Fujii, J; Nagai, R

1999-06-01

We studied the role of nitric oxide (NO) synthesis in amelioration of blood pressure elevation during dietary salt loading in transgenic mice overexpressing sodium proton exchanger. Systolic blood pressure rose after starting salt loading only in the high-salt group of transgenic mice. However, this elevation of blood pressure was not continued. Urinary excretion of inorganic nitrite and nitrate in the high-salt group of transgenic mice was significantly higher than in the high-salt group of control mice. These results suggest that increased NO synthesis in response to salt loading is one of the anti-hypertensive mechanisms in transgenic mice overexpressing sodium proton exchanger.

Immediate effects of different schedules of somatostatin on portal pressure in patients with liver cirrhosis.

PubMed

Zhang, C; Xu, J-M; Kong, D-R; Min, X-K; Chen, R

2013-06-01

Somatostatin (SST) is used for the treatment of acute variceal bleeding based on its ability to decrease portal pressure and collateral blood flow. To date, no studies have focused on the immediate-early effects (between 1 and 30 min) of SST. The aim of this study was to compare the efficacy of different schedules of SST therapy with placebo on portal pressure in patients with portal hypertension treated with portal-azygous disconnection and to test whether an increase in bolus or infusion dose can improve the clinical efficacy of SST therapy.   Patients were treated with four different schedules: (a) standard dose (n = 11): one 250 μg bolus + a continuous infusion of 250 μg/h; (b) medium dose (n = 10): 500 μg bolus + a continuous infusion of 250 μg/h; (c) high dose (n = 10): 250 μg bolus + a continuous infusion of 500 μg/h; (d) control (n = 10): an injection of placebo (saline) followed by a placebo infusion. Following SST or placebo administration, portal pressure, central venous pressure (CVP), systemic blood pressure and heart rate (HR) were measured at 1, 3, 5, 7, 10 and 30 min.   The three schedules of SST induced a marked, rapid and highly significant decrease in portal pressure. The decline in portal pressure was moderate at 1 min (P < 0·040), achieved a peak effect at 5 min (P < 0·009) and remained decreased at 30 min. The effect of SST on portal pressure was significantly greater than placebo from 1 min after administration. There were no significant differences in portal pressure decrease between the three schedules of SST. The three schedules of SST and the placebo schedule did not induce significant changes in HR, systemic blood pressure and CVP.   This study shows that SST is effective in decreasing portal pressure within 30 min of administration in patients with liver cirrhosis. The clinical schedule used in this study was reasonable and safe. © 2013 Blackwell Publishing Ltd.

40 CFR 63.11567 - Who implements and enforces this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...). 2. A high-efficiency air filter or fiber bed filter a. Inlet gas temperature b, andb. Pressure drop...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Asphalt...

Background Pressure Effects on Krypton Hall Effect Thruster Internal Acceleration

DTIC Science & Technology

2013-08-01

This was also previously seen for xenon. Several interpretations of the continued velocity dis- tribution broadening of the high pressure case of...acceleration region into the thruster rel- ative to lower background pressures. We have at- tributed this behavior to increased electron mobility...density. While the data presented thus far does shown some changes in the breadth of the velocity Kr II dis- tributions with increasing

Effect of geometrical parameters on pressure distributions of impulse manufacturing technologies

NASA Astrophysics Data System (ADS)

Brune, Ryan Carl

Impulse manufacturing techniques constitute a growing field of methods that utilize high-intensity pressure events to conduct useful mechanical operations. As interest in applying this technology continues to grow, greater understanding must be achieved with respect to output pressure events in both magnitude and distribution. In order to address this need, a novel pressure measurement has been developed called the Profile Indentation Pressure Evaluation (PIPE) method that systematically analyzes indentation patterns created with impulse events. Correlation with quasi-static test data and use of software-assisted analysis techniques allows for colorized pressure maps to be generated for both electromagnetic and vaporizing foil actuator (VFA) impulse forming events. Development of this technique aided introduction of a design method for electromagnetic path actuator systems, where key geometrical variables are considered using a newly developed analysis method, which is called the Path Actuator Proximal Array (PAPA) pressure model. This model considers key current distribution and proximity effects and interprets generated pressure by considering the adjacent conductor surfaces as proximal arrays of individual conductors. According to PIPE output pressure analysis, the PAPA model provides a reliable prediction of generated pressure for path actuator systems as local geometry is changed. Associated mechanical calculations allow for pressure requirements to be calculated for shearing, flanging, and hemming operations, providing a design process for such cases. Additionally, geometry effect is investigated through a formability enhancement study using VFA metalworking techniques. A conical die assembly is utilized with both VFA high velocity and traditional quasi-static test methods on varied Hasek-type sample geometries to elicit strain states consistent with different locations on a forming limit diagram. Digital image correlation techniques are utilized to measure major and minor strains for each sample type to compare limit strain results. Overall testing indicated decreased formability at high velocity for 304 DDQ stainless steel and increased formability at high velocity for 3003-H14 aluminum. Microstructural and fractographic analysis helped dissect and analyze the observed differences in these cases. Overall, these studies comprehensively explore the effects of geometrical parameters on magnitude and distribution of impulse manufacturing generated pressure, establishing key guidelines and models for continued development and implementation in commercial applications.

Restoration of Pulsatile Flow Reduces Sympathetic Nerve Activity Among Individuals With Continuous-Flow Left Ventricular Assist Devices.

PubMed

Cornwell, William K; Tarumi, Takashi; Stickford, Abigail; Lawley, Justin; Roberts, Monique; Parker, Rosemary; Fitzsimmons, Catherine; Kibe, Julius; Ayers, Colby; Markham, David; Drazner, Mark H; Fu, Qi; Levine, Benjamin D

2015-12-15

Current-generation left ventricular assist devices provide circulatory support that is minimally or entirely nonpulsatile and are associated with marked increases in muscle sympathetic nerve activity (MSNA), likely through a baroreceptor-mediated pathway. We sought to determine whether the restoration of pulsatile flow through modulations in pump speed would reduce MSNA through the arterial baroreceptor reflex. Ten men and 3 women (54 ± 14 years) with Heartmate II continuous-flow left ventricular assist devices underwent hemodynamic and sympathetic neural assessment. Beat-to-beat blood pressure, carotid ultrasonography at the level of the arterial baroreceptors, and MSNA via microneurography were continuously recorded to determine steady-state responses to step changes (200-400 revolutions per minute) in continuous-flow left ventricular assist device pump speed from a maximum of 10,480 ± 315 revolutions per minute to a minimum of 8500 ± 380 revolutions per minute. Reductions in pump speed led to increases in pulse pressure (high versus low speed: 17 ± 7 versus 26 ± 12 mm Hg; P<0.01), distension of the carotid artery, and carotid arterial wall tension (P<0.05 for all measures). In addition, MSNA was reduced (high versus low speed: 41 ± 15 versus 33 ± 16 bursts per minute; P<0.01) despite a reduction in mean arterial pressure and was inversely related to pulse pressure (P=0.037). Among subjects with continuous-flow left ventricular assist devices, the restoration of pulsatile flow through modulations in pump speed leads to increased distortion of the arterial baroreceptors with a subsequent decline in MSNA. Additional study is needed to determine whether reduction of MSNA in this setting leads to improved outcomes. © 2015 American Heart Association, Inc.

High-Pressure Synthesis: A New Frontier in the Search for Next-Generation Intermetallic Compounds.

PubMed

Walsh, James P S; Freedman, Danna E

2018-06-19

The application of high pressure adds an additional dimension to chemical phase space, opening up an unexplored expanse bearing tremendous potential for discovery. Our continuing mission is to explore this new frontier, to seek out new intermetallic compounds and new solid-state bonding. Simple binary elemental systems, in particular those composed of pairs of elements that do not form compounds under ambient pressures, can yield novel crystalline phases under compression. Thus, high-pressure synthesis can provide access to solid-state compounds that cannot be formed with traditional thermodynamic methods. An emerging approach for the rapid exploration of composition-pressure-temperature phase space is the use of hand-held high-pressure devices known as diamond anvil cells (DACs). These devices were originally developed by geologists as a way to study minerals under conditions relevant to the earth's interior, but they possess a host of capabilities that make them ideal for high-pressure solid-state synthesis. Of particular importance, they offer the capability for in situ spectroscopic and diffraction measurements, thereby enabling continuous reaction monitoring-a powerful capability for solid-state synthesis. In this Account, we provide an overview of this approach in the context of research we have performed in the pursuit of new intermetallic compounds. We start with a discussion of pressure as a fundamental experimental variable that enables the formation of intermetallic compounds that cannot be isolated under ambient conditions. We then introduce the DAC apparatus and explain how it can be repurposed for use as a synthetic vessel with which to explore this phase space, going to extremes of pressure where no chemist has gone before. The remainder of the Account is devoted to discussions of recent experiments we have performed with this approach that have led to the discovery of novel intermetallic compounds in the Fe-Bi, Cu-Bi, and Ni-Bi systems, with a focus on the cutting-edge methods that made these experiments possible. We review the use of in situ laser heating at high pressure, which led to the discovery of FeBi 2 , the first binary intermetallic compound in the Fe-Bi system. Our work in the Cu-Bi system is described in the context of in situ experiments carried out in the DAC to map its high-pressure phase space, which revealed two intermetallic phases (Cu 11 Bi 7 and CuBi). Finally, we review the discovery of β-NiBi, a novel high-pressure phase in the Ni-Bi system. We hope that this Account will inspire the next generation of solid-state chemists to boldly explore high-pressure phase space.

Continuity and Change in Appalachia.

ERIC Educational Resources Information Center

Shinn, Larry D.

1999-01-01

Appalachian continuities include attachment to land and religion, high teen pregnancy, and low literacy and income. Trends in Appalachia that institutions of higher education must address are higher rates of college attendance, migration to urban areas, changes in student learning styles, and increasing pressure to educate students to workplace…

46 CFR 193.15-1 - Application.

Code of Federal Regulations, 2014 CFR

2014-10-01

... requirements of this subpart are based on a “high pressure system,” i.e., one in which the carbon dioxide is stored in liquid form at atmospheric temperature. Details for “low pressure systems,” i.e., those in which the carbon dioxide is stored in liquid form at a continuously controlled low temperature, may be...

46 CFR 193.15-1 - Application.

Code of Federal Regulations, 2013 CFR

2013-10-01

... requirements of this subpart are based on a “high pressure system,” i.e., one in which the carbon dioxide is stored in liquid form at atmospheric temperature. Details for “low pressure systems,” i.e., those in which the carbon dioxide is stored in liquid form at a continuously controlled low temperature, may be...

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

DOE PAGES

Palmer, Alexander; Silevitch, Daniel; Feng, Yejun; ...

2015-09-04

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

Kinetic extruder - a dry pulverized solid material pump

DOEpatents

Meyer, J. W.; Bonin, J. H.; Daniel, A. D. Jr.

1983-03-15

Method and apparatus are shown for the continuous feeding of pulverized material to a high pressure container. A rotor is located within the high pressure container. The pulverized material is fed from a feed hopper through a stationary feed pipe to a vented spin-up chamber to a plurality of two-stage sprues mounted in the rotor. Control nozzles downstream from the sprues meter the flow of coal through the sprues. 19 figs.

Multiple pathways in pressure-induced phase transition of coesite

NASA Astrophysics Data System (ADS)

Liu, Wei; Wu, Xuebang; Liang, Yunfeng; Liu, Changsong; Miranda, Caetano R.; Scandolo, Sandro

2017-12-01

High-pressure single-crystal X-ray diffraction method with precise control of hydrostatic conditions, typically with helium or neon as the pressure-transmitting medium, has significantly changed our view on what happens with low-density silica phases under pressure. Coesite is a prototype material for pressure-induced amorphization. However, it was found to transform into a high-pressure octahedral (HPO) phase, or coesite-II and coesite-III. Given that the pressure is believed to be hydrostatic in two recent experiments, the different transformation pathways are striking. Based on molecular dynamic simulations with an ab initio parameterized potential, we reproduced all of the above experiments in three transformation pathways, including the one leading to an HPO phase. This octahedral phase has an oxygen hcp sublattice featuring 2 × 2 zigzag octahedral edge-sharing chains, however with some broken points (i.e., point defects). It transforms into α-PbO2 phase when it is relaxed under further compression. We show that the HPO phase forms through a continuous rearrangement of the oxygen sublattice toward hcp arrangement. The high-pressure amorphous phases can be described by an fcc and hcp sublattice mixture.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xuebing; Chen, Ting; Qi, Xintong

In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al{sub 2}O{sub 3} were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in anmore » offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al{sub 2}O{sub 3} pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.« less

Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

PubMed

Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

2016-09-01

Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

Effects of high NaCl diet on arterial pressure in Sprague-Dawley rats with hepatic and sinoaortic denervation.

PubMed

Gao, Shuang; Tanaka, Kunihiko; Gotoh, Taro M; Morita, Hironobu

2005-08-01

The Na(+) receptor that exists in the hepatoportal region plays an important role in postprandial natriuresis and the regulation of Na(+) balance during NaCl load. Thus it would be considered that a dysfunction of the hepatic Na(+) receptor might result in the elevation of arterial pressure under a condition of high NaCl diet. To elucidate this hypothesis, arterial pressure was continuously measured during three weeks of high NaCl diet (8% NaCl) in four groups of rats: (i) intact rats, (ii) rats with hepatic denervation (HD), (iii) rats with sinoaortic denervation (SAD), and (iv) rats with SAD+HD. During a 1-week normal NaCl diet period, there was no difference in arterial pressure among the four groups. A high NaCl diet had no influence on arterial pressure in intact or HD rats; however, it significantly increased by 11 +/- 3 mmHg in SAD rats. The addition of HD to SAD had no synergistic effect on arterial pressure; i.e., in SAD+HD rats, mean arterial pressure increased by 13 +/- 1 mmHg. In conclusion, sinoaortic baroreceptor, but not hepatic Na(+) receptor, has a significant role in the long-term regulation of arterial pressure on a high NaCl diet.

Preventing Continuous Positive Airway Pressure Failure: Evidence-Based and Physiologically Sound Practices from Delivery Room to the Neonatal Intensive Care Unit.

PubMed

Wright, Clyde J; Sherlock, Laurie G; Sahni, Rakesh; Polin, Richard A

2018-06-01

Routine use of continuous positive airway pressure (CPAP) to support preterm infants with respiratory distress is an evidenced-based strategy to decrease incidence of bronchopulmonary dysplasia. However, rates of CPAP failure remain unacceptably high in very premature neonates, who are at high risk for developing bronchopulmonary dysplasia. Using the GRADE framework to assess the quality of available evidence, this article reviews strategies aimed at decreasing CPAP failure, starting with delivery room interventions and followed through to system-based efforts in the neonatal intensive care unit. Despite best efforts, some very premature neonates fail CPAP. Also reviewed are predictors of CPAP failure in this vulnerable population. Copyright © 2018 Elsevier Inc. All rights reserved.

Pressure induced metallization with absence of structural transition in layered molybdenum diselenide

PubMed Central

Zhao, Zhao; Zhang, Haijun; Yuan, Hongtao; Wang, Shibing; Lin, Yu; Zeng, Qiaoshi; Xu, Gang; Liu, Zhenxian; Solanki, G. K.; Patel, K. D.; Cui, Yi; Hwang, Harold Y.; Mao, Wendy L.

2015-01-01

Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures away from the pristine states. Here, we systematically investigated the pressurized behavior of MoSe2 up to ∼60 GPa using multiple experimental techniques and ab-initio calculations. MoSe2 evolves from an anisotropic two-dimensional layered network to a three-dimensional structure without a structural transition, which is a complete contrast to MoS2. The role of the chalcogenide anions in stabilizing different layered patterns is underscored by our layer sliding calculations. MoSe2 possesses highly tunable transport properties under pressure, determined by the gradual narrowing of its band-gap followed by metallization. The continuous tuning of its electronic structure and band-gap in the range of visible light to infrared suggest possible energy-variable optoelectronics applications in pressurized transition-metal dichalcogenides. PMID:26088416

Pressure induced metallization with absence of structural transition in layered molybdenum diselenide

DOE PAGES

Zhao, Zhao; Zhang, Haijun; Yuan, Hongtao; ...

2015-06-19

Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures away from the pristine states. Here, we systematically investigated the pressurized behavior of MoSe 2 up to ~60 GPa using multiple experimental techniques and ab-initio calculations. MoSe 2 evolves from an anisotropic two-dimensional layered network to a three-dimensional structure without a structural transition, which is a complete contrast to MoS 2. The role of the chalcogenide anions in stabilizing different layered patterns is underscored by our layer sliding calculations. MoSemore » 2 possesses highly tunable transport properties under pressure, determined by the gradual narrowing of its band-gap followed by metallization. The continuous tuning of its electronic structure and band-gap in the range of visible light to infrared suggest possible energy-variable optoelectronics applications in pressurized transition-metal dichalcogenides.« less

Coarctation of the aorta

MedlinePlus

... brain Early development of coronary artery disease (CAD) Endocarditis (infection in the heart) Heart failure Hoarseness Kidney ... include: Continued or repeated narrowing of the aorta Endocarditis High blood pressure

Environmental Technology Verification Coatings and Coating Equipment Program (ETV CCEP). High Transfer Efficiency Spray Equipment - Generic Verification Protocol (Revision 0)

DTIC Science & Technology

2006-09-30

High-Pressure Waterjet • CO2 Pellet/Turbine Wheel • Ultrahigh-Pressure Waterjet 5 Process Water Reuse/Recycle • Cross-Flow Microfiltration ...documented on a process or laboratory form. Corrective action will involve taking all necessary steps to restore a measuring system to proper working order...In all cases, a nonconformance will be rectified before sample processing and analysis continues. If corrective action does not restore the

The importance of clinical monitoring for compliance with Continuous Positive Airway Pressure.

PubMed

Pelosi, Lucas B; Silveira, Mariana L C; Eckeli, Alan L; Chayamiti, Emilia M P C; Almeida, Leila A; Sander, Heidi H; Küpper, Daniel S; Valera, Fabiana C P

Obstructive sleep apnea syndrome is currently a public health problem of great importance. When misdiagnosed or improperly treated, it can lead to serious consequences on patients' quality of life. The gold standard treatment for cases of obstructive sleep apnea syndrome, especially in mild to severe and symptomatic cases, is continuous positive airway pressure therapy. Compliance with continuous positive airway pressure therapy is directly dependent on the active participation of the patient, which can be influenced by several factors. The objective of this study is to describe the factors related to compliance with continuous positive airway pressure therapy, and to analyze which associated factors directly influence the efficiency of the treatment. Patients who received continuous positive airway pressure therapy through the Municipal Health Department of the city of Ribeirão Preto were recruited. A structured questionnaire was administered to the patients. Compliance with continuous positive airway pressure therapy was assessed by average hours of continuous positive airway pressure therapy usage per night. Patients with good compliance (patients using continuous positive airway pressure therapy ≥4h/night) were compared to those with poor compliance (patients using <4h/night). 138 patients were analyzed: 77 (55.8%) were considered compliant while 61 (44.2%) were non-compliant. The comparison between the two groups showed that regular monitoring by a specialist considerably improved compliance with continuous positive airway pressure therapy (odds ratio, OR=2.62). Compliance with continuous positive airway pressure therapy is related to educational components, which can be enhanced with continuous and individualized care to patients with obstructive sleep apnea syndrome. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Income inequality and high blood pressure in Colombia: a multilevel analysis.

PubMed

Lucumi, Diego I; Schulz, Amy J; Roux, Ana V Diez; Grogan-Kaylor, Andrew

2017-11-21

The objective of this research was to examine the association between income inequality and high blood pressure in Colombia. Using a nationally representative Colombian sample of adults, and data from departments and municipalities, we fit sex-stratified linear and logistic multilevel models with blood pressure as a continuous and binary variable, respectively. In adjusted models, women living in departments with the highest quintile of income inequality in 1997 had higher systolic blood pressure than their counterparts living in the lowest quintile of income inequality (mean difference 4.42mmHg; 95%CI: 1.46, 7.39). Women living in departments that were at the fourth and fifth quintile of income inequality in 1994 were more likely to have hypertension than those living in departments at the first quintile in the same year (OR: 1.56 and 1.48, respectively). For men, no associations of income inequality with either systolic blood pressure or hypertension were observed. Our findings are consistent with the hypothesis that income inequality is associated with increased risk of high blood pressure for women. Future studies to analyze pathways linking income inequality to high blood pressure in Colombia are needed.

Reappraisal of quantitative evaluation of pulmonary regurgitation and estimation of pulmonary artery pressure by continuous wave Doppler echocardiography.

PubMed

Lei, M H; Chen, J J; Ko, Y L; Cheng, J J; Kuan, P; Lien, W P

1995-01-01

This study assessed the usefulness of continuous wave Doppler echocardiography and color flow mapping in evaluating pulmonary regurgitation (PR) and estimating pulmonary artery (PA) pressure. Forty-three patients were examined, and high quality Doppler spectral recordings of PR were obtained in 32. All patients underwent cardiac catheterization, and simultaneous PA and right ventricular (RV) pressures were recorded in 17. Four Doppler regurgitant flow velocity patterns were observed: pandiastolic plateau, biphasic, peak and plateau, and early diastolic triangular types. The peak diastolic and end-diastolic PA-to-RV pressure gradients derived from the Doppler flow profiles correlated well with the catheter measurements (r = 0.95 and r = 0.95, respectively). As PA pressure increased, the PR flow velocity became higher; a linear relationship between either systolic or mean PA pressure and Doppler-derived peak diastolic pressure gradient was noted (r = 0.90 and 0.94, respectively). Based on peak diastolic gradients of < 15, 15-30 or > 30 mm Hg, patients could be separated as those with mild, moderate or severe pulmonary hypertension, respectively (p < 0.05). A correlation was also observed between PA diastolic pressure and Doppler-derived end-diastolic pressure gradient (r = 0.91). Moreover, the Doppler velocity decay slope of PR closely correlated with that derived from the catheter method (r = 0.98). The decay slope tended to be steeper with the increment in regurgitant jet area and length obtained from color flow mapping. In conclusion, continuous wave Doppler evaluation of PR is a useful means for noninvasive estimation of PA pressure, and the Doppler velocity decay slope seems to reflect the severity of PR.

Application of Formation Testing While Drilling (GeoTap) for acquiring formation pressure data from the Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic

NASA Astrophysics Data System (ADS)

Amirov, Elnur

2016-04-01

A new technology to acquire wireline quality pressure tests using a Logging While Drilling approach has been successfully implemented few years ago in Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic. The Formation Tester While Drilling tool (GeoTap) uses a testing sequence similar to wireline tools. A single probe is extended to the borehole wall and a small pretest volume withdrawn from the formation. The resulting pressure transient is then analyzed for formation pressure, formation permeability and mobility information. Up-link and down-link capabilities have been added to achieve test control and quality feedback. An efficient downlink algorithm is used downhole to analyze the data. The parameters and pressure data are transmitted to the surface in real-time for continuous monitoring of the test. More detailed pressure data is recorded and retrieved after returning to surface. Use of a quartz gauge allows excellent accuracy. Azeri, Chirag and Guneshli fields consist of layered sand reservoirs alternation with shale sequences and detailed pressure data is acquired on a high percentage of wells in order to understand lateral and vertical continuity of different flow units. The formation tester can be utilized with the 'triple combo' Logging While Drilling string which eliminates the need to rig up wireline on many wells. Wireline formation tester runs are time consuming - particularly if high deviation or high overbalance conditions are encountered requiring pipe conveyed techniques. Non-Productive Time is high when the wireline tools are stuck and fishing operations are required. The Sperry Drilling GeoTap formation pressure tester service provides real-time formation pressure measurements. It bridges the critical gap between drilling safety and optimization, by providing early and reliable measurements of key reservoir properties, while improving reservoir understanding and completion design in real time. The GeoTap tester obtains direct pore-pressure measurements as the well is being drilled, with accuracy and precision comparable to that of wireline testers. The GeoTap service can eliminate the time, risk, and cost associated with running pipe-conveyed wireline test tools. It also measures annular and bore pressure while drilling, providing accurate, continuous, real-time hydrostatic pressure, and equivalent circulating density (ECD) information. This aids in determining and maintaining optimal mud weight, reduces formation damage, increases the rate of penetration, and increases operational safety. GeoTap benefits can be improvement of formation evaluation, real-time fluid gradients and fluid mobility (permeability/viscosity indicator), identification of fluid contact points, determination of reservoir connectivity/compartmentalization and depletion, increase safety of operation, determination of optimal mud weight and manage of ECD. We can also continuously monitor wellbore stability for assessments in order to reduce formation damage which in turns will help to increase drilling effectiveness (determine precise overbalance for maximizing ROP and continuously monitor hole-cleaning effectiveness with pressure-while-drilling, while reducing formation damage due to swab/surge). Save time and money by reducing rig down time associated with wireline testing. GeoTap Tool capable of performing more than 150 pressure tests per run and optional orientation of pressure measurement is available (top, right, bottom or left). GeoTap testing has been completed with encouraging results in many wells up to circa 3000m deep. Data has been acquired successfully both in a "Drill-Test-Drill' mode and a "Post-Drill-Test" mode. GeoTap tests have spanned wide ranges of borehole temperature, pressure, mobility as well as formation permeability and overbalance conditions. GeoTap tests in Azeri, Chirag and Guneshli wells which were drilled in the Khazarian-Caspian Sea of the Azerbaijan Republic have proved that a logging while drilling approach can be successfully employed to acquire formation pressure data in open hole (which is also very useful for fluid gradient analysis, oil water and gas oil contacts delineation/identification).

Design of distributed JT (Joule-Thomson) effect heat exchanger for superfluid 2 K cooling device

NASA Astrophysics Data System (ADS)

Jeong, S.; Park, C.; Kim, K.

2018-03-01

Superfluid at 2 K or below is readily obtained from liquid helium at 4.2 K by reducing its vapour pressure. For better cooling performance, however, the cold energy of vaporized helium at 2 K chamber can be effectively utilized in a recuperator which is specially designed in this paper for accomplishing so-called the distributed Joule-Thomson (JT) expansion effect. This paper describes the design methodology of distributed JT effect heat exchanger for 2 K JT cooling device. The newly developed heat exchanger allows continuous significant pressure drop at high-pressure part of the recuperative heat exchanger by using a capillary tube. Being different from conventional recuperative heat exchangers, the efficient JT effect HX must consider the pressure drop effect as well as the heat transfer characteristic. The heat exchanger for the distributed JT effect actively utilizes continuous pressure loss at the hot stream of the heat exchanger by using an OD of 0.64 mm and an ID of 0.4 mm capillary tube. The analysis is performed by dividing the heat exchanger into the multiple sub-units of the heat exchange part and JT valve. For more accurate estimation of the pressure drop of spirally wound capillary tube, preliminary experiments are carried out to investigate the friction factor at high Reynolds number. By using the developed pressure drop correlation and the heat transfer correlation, the specification of the heat exchanger with distributed JT effect for 2 K JT refrigerator is determined.

Bubble continuous positive airway pressure in a human immunodeficiency virus-infected infant

PubMed Central

McCollum, E. D.; Smith, A.; Golitko, C. L.

2014-01-01

SUMMARY World Health Organization-classified very severe pneumonia due to Pneumocystis jirovecii infection is recognized as a life-threatening condition in human immunodeficiency virus (HIV) infected infants. We recount the use of nasal bubble continuous positive airway pressure (BCPAP) in an HIV-infected African infant with very severe pneumonia and treatment failure due to suspected infection with P. jirovecii. We also examine the potential implications of BCPAP use in resource-poor settings with a high case index of acute respiratory failure due to HIV-related pneumonia, but limited access to mechanical ventilation. PMID:21396221

High pressure liquid chromatographic gradient mixer

DOEpatents

Daughton, Christian G.; Sakaji, Richard H.

1985-01-01

A gradient mixer which effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum "band-broadening".

High-pressure liquid chromatographic gradient mixer

DOEpatents

Daughton, C.G.; Sakaji, R.H.

1982-09-08

A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

Methylation of 2-Naphthol Using Dimethyl Carbonate under Continuous-Flow Gas-Phase Conditions

ERIC Educational Resources Information Center

Tundo, Pietro; Rosamilia, Anthony E.; Arico, Fabio

2010-01-01

This experiment investigates the methylation of 2-naphthol with dimethyl carbonate. The volatility of the substrates, products, and co-products allows the reaction to be performed using a continuous-flow gas-phase setup at ambient pressure. The reaction uses catalytic quantities of base, achieves high conversion, produces little waste, and…

An Exploration of At-Risk Students' Journeys through a Continuation High School

ERIC Educational Resources Information Center

Putney, David

2010-01-01

There is a void of current research on continuation schools and the students who attend these unique and historic educational institutions (Kelly, 1993). In an era of increased pressure surrounding student performance, of tight financial constraints, and of a changing landscape of student demographics, this study attempts to explore and understand…

Smart-actuated continuous moldline technology (CMT) mini wind tunnel test

NASA Astrophysics Data System (ADS)

Pitt, Dale M.; Dunne, James P.; Kilian, Kevin J.

1999-07-01

The Smart Aircraft and Marine Propulsion System Demonstration (SAMPSON) Program will culminate in two separate demonstrations of the application of Smart Materials and Structures technology. One demonstration will be for an aircraft application and the other for marine vehicles. The aircraft portion of the program will examine the application of smart materials to aircraft engine inlets which will deform the inlet in-flight in order to regulate the airflow rate into the engine. Continuous Moldline Technology (CMT), a load-bearing reinforced elastomer, will enable the use of smart materials in this application. The capabilities of CMT to withstand high-pressure subsonic and supersonic flows were tested in a sub-scale mini wind- tunnel. The fixture, used as the wind-tunnel test section, was designed to withstand pressure up to 100 psi. The top and bottom walls were 1-inch thick aluminum and the side walls were 1-inch thick LEXAN. High-pressure flow was introduced from the Boeing St. Louis poly-sonic wind tunnel supply line. CMT walls, mounted conformal to the upper and lower surfaces, were deflected inward to obtain a converging-diverging nozzle. The CMT walls were instrumented for vibration and deflection response. Schlieren photography was used to establish shock wave motion. Static pressure taps, embedded within one of the LEXAN walls, monitored pressure variation in the mini-wind tunnel. High mass flow in the exit region. This test documented the response of CMT technology in the presence of high subsonic flow and provided data to be used in the design of the SAMPSON Smart Inlet.

Joint AIRAPT-25th and EHPRG-53rd International Conference on High Pressure Science and Technology

NASA Astrophysics Data System (ADS)

Syassen, Karl

2017-10-01

The AIRAPT arose as a scientific forum for discussions aiming to promote contacts and cooperation between scientists and organizations of different countries, to collect and disseminate of information, having the advancement of science and technology in the field of high pressure as main objective. Nowadays the field has experienced an astonishing growth in an open multidisciplinary environment that rather contributed to the creation of different interdisciplinary teams of excellence, being able to face the important challenges posed by high-pressure research. Great achievements have been possible towards higher pressures, nowadays making possible experiments in the TPa range in our laboratories, the improvement and adaptation of different characterization techniques of matter under extreme conditions of pressure and temperature or the development of efficient ab initio methods with capabilities to explain and eventually predict new physical phenomena and materials design. All decisively contributed to the advance of science and understanding of nature, with high pressure as common leitmotiv. On the 50th Anniversary of the AIRAPT, this talk will is intended to commemorate the enthusiastic and encouraging work of high-pressure pioneers and to motivate young scientists to join us and continue the challenge of exploring compressed matter as a way to unveil new phenomena and materials and a better understanding of our world.

[Long-term prognosis of idiopathic chronic adult hydrocephalus: I. The University Hospital Marqués de Valdecilla diagnostic and therapeutic protocol].

PubMed

Martín-Láez, Rubén; Vázquez-Barquero, Alfonso

Despite the existence of published guidelines for more than a decade, there is still a substantial variation in the management of idiopathic normal pressure hydrocephalus due to its diagnostic and therapeutic complexity. The diagnostic and therapeutic protocol for the management of idiopathic normal pressure hydrocephalus in use at the Department of Neurosurgery of the University Hospital Marqués de Valdecilla is presented. The diagnostic process includes neuropsychological testing, phase contrast cine MRI, urodynamic evaluation, continuous intracranial pressure monitoring, cerebrospinal fluid hydrodynamics by means of lumbar infusion testing, and intra-abdominal pressure measurement. A patient is considered a surgical candidate if any of the following criteria is met: mean intracranial pressure >15mmHg, or B-waves present in >10% of overnight recording; pressure-volume index <15ml, or resistance to cerebrospinal fluid outflow (R OUT ) >4.5mmHg/ml/min in bolus infusion test; R OUT >12mmHg/ml/min, intracranial pressure >22mmHg, or high amplitude B-waves in the steady-state of the continuous rate infusion test; or a clinical response to high-volume cerebrospinal fluid withdrawal. The implementation of a diagnostic and therapeutic protocol for idiopathic normal pressure hydrocephalus management could improve various aspects of patient care. It could reduce variability in clinical practice, optimise the use of health resources, and help in identifying scientific uncertainty areas, in order to direct research efforts in a more appropriate way. Copyright © 2016 Sociedad Española de Neurocirugía. Publicado por Elsevier España, S.L.U. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, A; Silevitch, D M; Feng, Yejun

2015-09-01

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

Gasdynamic Inlet Isolation in Rotating Detonation Engine

DTIC Science & Technology

2010-12-01

2D Total Variation Diminishing (TVD): Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Total Variation Diminishing (TVD) limiter: Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Continuous 94 Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate pressure gradient switch: Normal

High-pressure structural behavior of hydrogarnet, katoite Ca3Al2(O4H4)3

NASA Astrophysics Data System (ADS)

Kyono, A.; Kato, M.; Sano-Furukawa, A.; Machida, S. I.; Hattori, T.

2016-12-01

High-pressure structural behavior of hydrogarnet, katoite Ca3Al2(O4H4)3, was investigated using single-crystal synchrotron x-ray diffraction, Raman spectroscopic, and neutron diffraction analyses. The high-pressure single-crystal synchrotron x-ray diffraction was performed at BL10A, Photon Factory, KEK, Japan. With compression, the a lattice parameter decreased continuously from 12.565 (1) Å to 12.226 (3) Å up to 7.1 GPa. A fit to the Birch-Murnaghan equation of state (EoS) based on the P-V data gives K0 = 56.0 (6) GPa, K' = 4.3 (1), and V0 = 1984.2 (5) Å3, which were consistent with the previous study by Lager et al. (2002). Weak reflections forbidden by the systematic absence of hk0 with k, l = 2n were observed at 5.5 GPa and their intensities became stronger as increasing pressure. The pattern change of systematic absence implies phase transformation from space group Ia-3d to its non-centrosymmetric space group I-43d. High-pressure Raman spectroscopic study was performed up to 8.3 GPa at room temperature. The pressure dependence of lattice modes showed a positive pressure shifts, whereas that of OH stretching vibration mode was changed negative above 5.1 GPa. The change indicates that the strength of hydrogen bonding turns to increase above 5.1 GPa. High-pressure and high-temperature neutron diffraction study was performed with six-axis large volume press, ATSUHIME, at BL11 (PLANET), J-PARC, Japan. At a pressure of approximately 8 GPa, the a lattice parameter increased with temperature, but neither thermal decomposition nor dehydroxylation process occurred up to 1123 K. The crystal structure of katoite was determined by Rietveld method using neutron diffraction data with the space group I-43d. The volume of dodecahedral site containing Ca cations and that of octahedral site occupied by Al cations remained almost constant with temperature, but two crystallographically inequivalent tetrahedral sites which were caused by phase transformation behaved differently from each other. The volume of T2 site was continuously increased, but that of T1 site was constantly decreased, resulting from anisotropic expansion of the dodecahedral site. Consequently, these anisotropic modifications of coordination polyhedra seem to induce the thermal decomposition of katoite at 1123 K and 8 GPa.

Apparatus for fixed bed coal gasification

DOEpatents

Sadowski, Richard S.

1992-01-01

An apparatus for fixed-bed coal gasification is described in which coal such as caking coal is continuously pyrolyzed with clump formation inhibited, by combining the coal with a combustible gas and an oxidant, and then continually feeding the pyrolyzed coal under pressure and elevated temperature into the gasification region of a pressure vessel. The materials in the pressure vessel are allowed to react with the gasifying agents in order to allow the carbon contents of the pyrolyzed coal to be completely oxidized. The combustion of gas produced from the combination of coal pyrolysis and gasification involves combining a combustible gas coal and an oxidant in a pyrolysis chamber and heating the components to a temperature of at least 1600.degree. F. The products of coal pyrolysis are dispersed from the pyrolyzer directly into the high temperature gasification region of a pressure vessel. Steam and air needed for gasification are introduced in the pressure vessel and the materials exiting the pyrolyzer flow down through the pressure vessel by gravity with sufficient residence time to allow any carbon to form carbon monoxide. Gas produced from these reactions are then released from the pressure vessel and ash is disposed of.

Efficacy of a pressure-sensing mattress cover system for reducing interface pressure: study protocol for a randomized controlled trial.

PubMed

Wong, Holly; Kaufman, Jaime; Baylis, Barry; Conly, John M; Hogan, David B; Stelfox, Henry T; Southern, Danielle A; Ghali, William A; Ho, Chester H

2015-09-29

Interface pressure is a key risk factor in the development of pressure ulcers. Visual feedback of continuous interface pressure between the body and support surface could inform clinicians on repositioning strategies and play a key role in an overall strategy for the prevention and management of pressure ulcers. A parallel two-group randomized controlled clinical trial will be conducted to study the effect of continuous pressure imaging on reducing interface pressure and on the incidence of pressure ulcers in vulnerable hospital patients. A total of 678 eligible consenting inpatients at risk of pressure ulcer development in a tertiary acute care institution will be randomly allocated to either having the ForeSite PT™ system with the liquid-crystal display monitor turned on to provide visual feedback to the clinicians while also collecting continuous interface pressure data (intervention group) or to having the ForeSite PT™ system with monitor turned off (that is, not providing visual feedback) but still collecting continuous interface pressure data (control group), in a ratio of 1:1. Continuous interface pressure data will be collected in both groups for 3 days (72 h). Data collection will continue until discharge for a subset of approximately 60 patients. The primary outcome will be the differences in the two groups' interface pressure analysis. Interface pressure readings will be collected through hourly samplings of continuous interface pressure recordings. Secondary outcomes will be the differences between the two groups in pressure-related skin and soft tissue changes in areas at risk of pressure ulcer (obtained at baseline within 24 h of admission) and on the third day of the trial or at discharge and perceptions of the intervention by patients and clinicians (obtained on the third day or at discharge). This will be the first randomized controlled trial to investigate the effect of visual feedback with continuous interface pressure of vulnerable hospital patients across different care settings, and the association between interface pressure and development of pressure-related skin and soft tissue changes. The results could provide important information to guide clinical practice in the prevention and management of pressure ulcers. ClinicalTrials.gov NCT02325388 (date of registration: 24 December 2014).

Kinetics of waterborne fluoropolymers prepared by one-step semi-continuous emulsion polymerization of chlorotrifluoroethylene, vinyl acetate, butyl acrylate and Veova 10

NASA Astrophysics Data System (ADS)

Liu, H. Z.; Wang, M. H.; Wang, Z. F.; Bian, J. M.

2018-01-01

Due to using gaseous fluorine monomer with toxicity, waterborne fluoropolymers are synthesized by semi-continuous high-pressure emulsion polymerization method which differs from free-pressure emulsion polymerization. To dates, the research on preparing process and kinetics for high-pressure emulsion polymerization is reported relatively less, which hinders researchers from understanding of mechanisms for monomer-fluorinated emulsion polymerization. The paper also provides a new method by element auxiliary analysis to calculate kinetics parameters of high-pressure emulsion polymerization. Based on aforementioned consideration, waterborne fluoropolymers were prepared by copolymerization of chlorotrifluoroethylene (CTFE), vinyl acetate (VAc), butyl acrylate (BA) and vinyl ester of versatic acid (Veova 10) using potassium persulfate as initiator and mixed surfactants. The kinetics of emulsion polymerization of waterborne fluoropolymers was then investigated. Effects of emulsifier concentration, initiator concentration, and polymerization temperature on polymerization rate (Rp) were evaluated, and relationship was described as Rp∝[I]0.10 and Rp∝[E]0.12. The apparent activation energy was determined to be 33.61 kJ·mol-1. Moreover, the relative conversion rate of CTFE with the other monomers was observed, and results indicated that CTFE monomer more uniformly copolymerized with the other monomers. The resulting emulsion properties and pressure change in an autoclave were evaluated at different stirring rates. The initial reaction time, defined as the beginning time of dropwise addition, was determined by the change in solid content and particle size of emulsion.

Individual characteristics of behavior, blood pressure, and adrenal hormones in colony rats.

PubMed

Fokkema, D S; Koolhaas, J M; van der Gugten, J

1995-05-01

Previous experiments suggested that rats with an active behavioral strategy and high endocrine and blood pressure responses to social interactions would be at risk to get a high blood pressure. To test this hypothesis, a long-term study of social behavior was performed in laboratory colonies of rats. The more aggressive rats, as indicated by individual precolony resident-intruder tests, are more aggressive in the colony also. After colony aggregation, the aggressive rats appeared to have higher resting blood pressures. The dominant rat (although aggressive, too) and the nonaggressive rats have lower blood pressures. Plasma levels of catecholamines and corticosterone after colony experience do not show a relation with blood pressure but reflect the rat's original precolony aggressive characteristic. We conclude that the individual characteristic of an active social strategy is a risk factor that indeed predicts the development of high blood pressure, possibly by way of the associated higher physiological reactivity we found earlier. Chronic environmental factors that are hard to control for the animal, like involvement in social processes or possibly other continuous challenges, may stimulate the prone physiology to develop an elevation of blood pressure.

Multiple pathways in pressure-induced phase transition of coesite

PubMed Central

Liu, Wei; Wu, Xuebang; Liu, Changsong; Miranda, Caetano R.; Scandolo, Sandro

2017-01-01

High-pressure single-crystal X-ray diffraction method with precise control of hydrostatic conditions, typically with helium or neon as the pressure-transmitting medium, has significantly changed our view on what happens with low-density silica phases under pressure. Coesite is a prototype material for pressure-induced amorphization. However, it was found to transform into a high-pressure octahedral (HPO) phase, or coesite-II and coesite-III. Given that the pressure is believed to be hydrostatic in two recent experiments, the different transformation pathways are striking. Based on molecular dynamic simulations with an ab initio parameterized potential, we reproduced all of the above experiments in three transformation pathways, including the one leading to an HPO phase. This octahedral phase has an oxygen hcp sublattice featuring 2 × 2 zigzag octahedral edge-sharing chains, however with some broken points (i.e., point defects). It transforms into α-PbO2 phase when it is relaxed under further compression. We show that the HPO phase forms through a continuous rearrangement of the oxygen sublattice toward hcp arrangement. The high-pressure amorphous phases can be described by an fcc and hcp sublattice mixture. PMID:29162690

Deviatoric stress-induced phase transitions in diamantane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Fan; Lin, Yu; Dahl, Jeremy E. P.

2014-10-21

The high-pressure behavior of diamantane was investigated using angle-dispersive synchrotron x-ray diffraction (XRD) and Raman spectroscopy in diamond anvil cells. Our experiments revealed that the structural transitions in diamantane were extremely sensitive to deviatoric stress. Under non-hydrostatic conditions, diamantane underwent a cubic (space group Pa3) to a monoclinic phase transition at below 0.15 GPa, the lowest pressure we were able to measure. Upon further compression to 3.5 GPa, this monoclinic phase transformed into another high-pressure monoclinic phase which persisted to 32 GPa, the highest pressure studied in our experiments. However, under more hydrostatic conditions using silicone oil as a pressuremore » medium, the transition pressure to the first high-pressure monoclinic phase was elevated to 7–10 GPa, which coincided with the hydrostatic limit of silicone oil. In another experiment using helium as a pressure medium, no phase transitions were observed to the highest pressure we reached (13 GPa). In addition, large hysteresis and sluggish transition kinetics were observed upon decompression. Over the pressure range where phase transitions were confirmed by XRD, only continuous changes in the Raman spectra were observed. This suggests that these phase transitions are associated with unit cell distortions and modifications in molecular packing rather than the formation of new carbon-carbon bonds under pressure.« less

[Development of a continuous blood pressure monitoring and recording system].

PubMed

Zhang, Yang; Li, Yong; Gao, Shumei; Song, Yilin

2012-09-01

A small experimental system is constructed with working principle of continuous blood pressure monitoring based on the volume compensation method. The preliminary experimental results show that the system can collect blood pressure signals at the radial artery effectively. The digital PID algorithm can track the variation of blood pressure. And the accuracy of continuous blood pressure detecting achieve the level of same kind of product.

High pressure storage vessel

DOEpatents

Liu, Qiang

2013-08-27

Disclosed herein is a composite pressure vessel with a liner having a polar boss and a blind boss a shell is formed around the liner via one or more filament wrappings continuously disposed around at least a substantial portion of the liner assembly combined the liner and filament wrapping have a support profile. To reduce susceptible to rupture a locally disposed filament fiber is added.

Influence of Surface Tension and Surface Shear on Final Coat Thickness in Jet-Stripped Continuous Coating of Sheet Materials.

DTIC Science & Technology

1983-11-01

galvanising industry, this pressure distribution is created by blowing a thin high-speed air jet onto the coated steel sheet, just after it emerges from the...if that free surface possesses curvature and non-zero surface tension, the internal pressure will differ from that in the jet. In the galvanising

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.; Oshiro, J.

2014-12-01

The Pacific GPS Facility and the Field Robotics Laboratory at the University of Hawaii have developed an approach to significantly reduce costs below ship based methods of accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure. Our goal has been to reduce the primary barrier preventing us from acquiring the observations we need to understand geodetic processes, and the hazards they present, at subduction zones, submarine volcanoes, and subsea landslides. To this end, we have designed a payload package for one of the University of Hawaii Wave Gliders which incorporates an acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, meteorological sensors, processing computer, and cellular communications. The Wave Glider will interrogate high accuracy pressure sensors on the seafloor to maintain a near-continuous stream of pressure and temperature data. The seafloor geodetic monument seats a sensor capable of recording pressure, temperature, and sound velocity for a deployment duration of over 5 years with an acoustic modem for communications, and an integral acoustic release for recovery and replacement of batteries. The design of the geodetic monument allows for precise repositioning of the sensor to extend the pressure record beyond a single 5+ year deployment, and includes the capability to install a mobile pressure recorder for calibration of the linear drift of the continuous pressure sensor. We will present the design of the Wave Glider payload and seafloor geodetic monument, as well as a discussion of nearshore and offshore field tests and operational procedures. An assessment of our ability to determine cm-scale vertical seafloor motions will be made by integrating the seafloor pressure measurements recovered during field testing with independent measurements of sea surface pressure and sea surface height made by the sea surface payload.

A reaction cell for ambient pressure soft x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Castán-Guerrero, C.; Krizmancic, D.; Bonanni, V.; Edla, R.; Deluisa, A.; Salvador, F.; Rossi, G.; Panaccione, G.; Torelli, P.

2018-05-01

We present a new experimental setup for performing X-ray Absorption Spectroscopy (XAS) in the soft X-ray range at ambient pressure. The ambient pressure XAS setup is fully compatible with the ultra high vacuum environment of a synchrotron radiation spectroscopy beamline end station by means of ultrathin Si3N4 membranes acting as windows for the X-ray beam and seal of the atmospheric sample environment. The XAS detection is performed in total electron yield (TEY) mode by probing the drain current from the sample with a picoammeter. The high signal/noise ratio achievable in the TEY mode, combined with a continuous scanning of the X-ray energies, makes it possible recording XAS spectra in a few seconds. The first results show the performance of this setup to record fast XAS spectra from sample surfaces exposed at atmospheric pressure, even in the case of highly insulating samples. The use of a permanent magnet inside the reaction cell enables the measurement of X-ray magnetic circular dichroism at ambient pressure.

Rapid Catalyst Screening by a Continuous-Flow Microreactor Interfaced with Ultra High Pressure Liquid Chromatography

PubMed Central

Fang, Hui; Xiao, Qing; Wu, Fanghui; Floreancig, Paul E.; Weber, Stephen G.

2010-01-01

A high-throughput screening system for homogeneous catalyst discovery has been developed by integrating a continuous-flow capillary-based microreactor with ultra-high pressure liquid chromatography (UHPLC) for fast online analysis. Reactions are conducted in distinct and stable zones in a flow stream that allows for time and temperature regulation. UHPLC detection at high temperature allows high throughput online determination of substrate, product, and byproduct concentrations. We evaluated the efficacies of a series of soluble acid catalysts for an intramolecular Friedel-Crafts addition into an acyliminium ion intermediate within one day and with minimal material investment. The effects of catalyst loading, reaction time, and reaction temperature were also screened. This system exhibited high reproducibility for high-throughput catalyst screening and allowed several acid catalysts for the reaction to be identified. Major side products from the reactions were determined through off-line mass spectrometric detection. Er(OTf)3, the catalyst that showed optimal efficiency in the screening, was shown to be effective at promoting the cyclization reaction on a preparative scale. PMID:20666502

High pressure-temperature electrical conductivity of magnesiowustite as a function of iron oxide concentration

NASA Technical Reports Server (NTRS)

Li, Xiaoyuan; Jeanloz, Raymond

1990-01-01

The electrical conductivity of (Mg, Fe)O magnesiowustite containing 9 and 27.5 mol pct FeO has been measured at simultaneously high pressures (30-32 GPa) and temperatures using a diamond anvil cell heated with a continuous wave Nd:YAG laser and an external resistance heater. The conductivity depends strongly on the FeO concentration at both ambient and high pressures. At the pressures and temperatures of about 30 GPa and 2000 K, conditions expected in the lower mantle, the magnesiowustite containing 27.5 percent FeO is 3 orders of magnitude more conductive than that containing 9 percent FeO. The activation energy of magnesiowustite decreases with increasing iron concentration from 0.38 (+ or - 0.09) eV at 9 percent FeO to 0.29 (+ or - 0.05) eV at 27.5 percent FeO.

Design, Simulation and Characteristics Research of the Interface Circuit based on nano-polysilicon thin films pressure sensor

NASA Astrophysics Data System (ADS)

Zhao, Xiaosong; Zhao, Xiaofeng; Yin, Liang

2018-03-01

This paper presents a interface circuit for nano-polysilicon thin films pressure sensor. The interface circuit includes consist of instrument amplifier and Analog-to-Digital converter (ADC). The instrumentation amplifier with a high common mode rejection ratio (CMRR) is implemented by three stages current feedback structure. At the same time, in order to satisfy the high precision requirements of pressure sensor measure system, the 1/f noise corner of 26.5 mHz can be achieved through chopping technology at a noise density of 38.2 nV/sqrt(Hz).Ripple introduced by chopping technology adopt continuous ripple reduce circuit (RRL), which achieves the output ripple level is lower than noise. The ADC achieves 16 bits significant digit by adopting sigma-delta modulator with fourth-order single-bit structure and digital decimation filter, and finally achieves high precision integrated pressure sensor interface circuit.

Design and Analysis of a Continuous Split Typed Needle-Free Injection System for Animal Vaccination.

PubMed

Chen, Kai; Pan, Min; Liu, Tingting

2017-01-01

Liquid needle-free injection devices (NFIDs) employ a high-velocity liquid jet to deliver drugs and vaccine through transdermal injection. NFIDs for animal vaccination are more complicated than those used for human beings for their much larger and more flexible power sources, as well as rapid, repetitive and continuous injection features. In the paper, spring-powered NFID is designed for animal vaccine injection. For convenience, the device is a split into a power source and handheld injector. A mathematical model is proposed to calculate the injection pressure, taking into the account pressure loss and the strain energy loss in the bendable tube due to elastic deformation. An experimental apparatus was build to verify the calculation results. Under the same system conditions, the calculation results of the dynamic injection pressure match the experimental results. It is found that the bendable tube of the split typed NFID has significant impact on the profile of the injection pressure. The initial peak pressure is less than the initial peak pressure of NFID without bendable tube, and there is occurrence time lag of the peak pressure. The mathematical model is the first attempt to reveal the relationship between the injection pressure and the system variables of split typed NFID.

Novel blood pressure and pulse pressure estimation based on pulse transit time and stroke volume approximation.

PubMed

Lee, Joonnyong; Sohn, JangJay; Park, Jonghyun; Yang, SeungMan; Lee, Saram; Kim, Hee Chan

2018-06-18

Non-invasive continuous blood pressure monitors are of great interest to the medical community due to their value in hypertension management. Recently, studies have shown the potential of pulse pressure as a therapeutic target for hypertension, but not enough attention has been given to non-invasive continuous monitoring of pulse pressure. Although accurate pulse pressure estimation can be of direct value to hypertension management and indirectly to the estimation of systolic blood pressure, as it is the sum of pulse pressure and diastolic blood pressure, only a few inadequate methods of pulse pressure estimation have been proposed. We present a novel, non-invasive blood pressure and pulse pressure estimation method based on pulse transit time and pre-ejection period. Pre-ejection period and pulse transit time were measured non-invasively using electrocardiogram, seismocardiogram, and photoplethysmogram measured from the torso. The proposed method used the 2-element Windkessel model to model pulse pressure with the ratio of stroke volume, approximated by pre-ejection period, and arterial compliance, estimated by pulse transit time. Diastolic blood pressure was estimated using pulse transit time, and systolic blood pressure was estimated as the sum of the two estimates. The estimation method was verified in 11 subjects in two separate conditions with induced cardiovascular response and the results were compared against a reference measurement and values obtained from a previously proposed method. The proposed method yielded high agreement with the reference (pulse pressure correlation with reference R ≥ 0.927, diastolic blood pressure correlation with reference R ≥ 0.854, systolic blood pressure correlation with reference R ≥ 0.914) and high estimation accuracy in pulse pressure (mean root-mean-squared error ≤ 3.46 mmHg) and blood pressure (mean root-mean-squared error ≤ 6.31 mmHg for diastolic blood pressure and ≤ 8.41 mmHg for systolic blood pressure) over a wide range of hemodynamic changes. The proposed pulse pressure estimation method provides accurate estimates in situations with and without significant changes in stroke volume. The proposed method improves upon the currently available systolic blood pressure estimation methods by providing accurate pulse pressure estimates.

Ultrasonic level sensors for liquids under high pressure

NASA Technical Reports Server (NTRS)

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

1986-01-01

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

High-pressure insulator-to-metal transition in Sr3Ir2O7 studied by x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Donnerer, C.; Sala, M. Moretti; Pascarelli, S.; Rosa, A. D.; Andreev, S. N.; Mazurenko, V. V.; Irifune, T.; Hunter, E. C.; Perry, R. S.; McMorrow, D. F.

2018-01-01

High-pressure x-ray absorption spectroscopy was performed at the Ir L3 and L2 absorption edges of Sr3Ir2O7 . The branching ratio of white-line intensities continuously decreases with pressure, reflecting a reduction in the angular part of the expectation value of the spin-orbit coupling operator, 〈L .S 〉 . Up to the high-pressure structural transition at 53 GPa, this behavior can be explained within a single-ion model, where pressure increases the strength of the cubic crystal field, which suppresses the spin-orbit induced hybridization of Jeff=3 /2 and eg levels. We observe a further reduction of the branching ratio above the structural transition, which cannot be explained within a single-ion model of spin-orbit coupling and cubic crystal fields. This change in 〈L .S 〉 in the high-pressure, metallic phase of Sr3Ir2O7 could arise from noncubic crystal fields or a bandwidth-driven hybridization of Jeff=1 /2 ,3 /2 states and suggests that the electronic ground state significantly deviates from the Jeff=1 /2 limit.

Inactivation of Staphylococcus aureus and Salmonella enteritidis in tryptic soy broth and caviar samples by high pressure processing.

PubMed

Fioretto, F; Cruz, C; Largeteau, A; Sarli, T A; Demazeau, G; El Moueffak, A

2005-08-01

We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 10(8)-10(9) colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar.

Fifty Years of Research in ARDS. Respiratory Mechanics in Acute Respiratory Distress Syndrome.

PubMed

Henderson, William R; Chen, Lu; Amato, Marcelo B P; Brochard, Laurent J

2017-10-01

Acute respiratory distress syndrome is a multifactorial lung injury that continues to be associated with high levels of morbidity and mortality. Mechanical ventilation, although lifesaving, is associated with new iatrogenic injury. Current best practice involves the use of small Vt, low plateau and driving pressures, and high levels of positive end-expiratory pressure. Collectively, these interventions are termed "lung-protective ventilation." Recent investigations suggest that individualized measurements of pulmonary mechanical variables rather than population-based ventilation prescriptions may be used to set the ventilator with the potential to improve outcomes beyond those achieved with standard lung protective ventilation. This review outlines the measurement and application of clinically applicable pulmonary mechanical concepts, such as plateau pressures, driving pressure, transpulmonary pressures, stress index, and measurement of strain. In addition, the concept of the "baby lung" and the utility of dynamic in addition to static measures of pulmonary mechanical variables are discussed.

Pressure-assisted thermal sterilization of soup

NASA Astrophysics Data System (ADS)

Shibeshi, Kidane; Farid, Mohammed M.

2010-12-01

The overall efficiency of an existing scale-up pressure-assisted thermal sterilization (PATS) unit was investigated with regards to inactivation of Geobacillus stearothermophilus spores suspended in pumpkin soup. The PATS unit is a double pipe heat exchanger in which the soup is pumped into its inner high pressure tube and constrained by two high pressure valves, while steam is continuously passed through the annular region to heat the content. The technology is based on pressure generation by thermal expansion of the liquid in an enclosure. In this work, the addition of an air line to push the treated liquid food out of the existing PATS unit has improved the overall quality of the treated samples, as evidenced by achieving higher log reduction of the spores. Compared with thermal processing, the application of PATS shows the potential for lowering the thermal treatment temperature, offering improved food quality.

Nitromethane decomposition under high static pressure.

PubMed

Citroni, Margherita; Bini, Roberto; Pagliai, Marco; Cardini, Gianni; Schettino, Vincenzo

2010-07-29

The room-temperature pressure-induced reaction of nitromethane has been studied by means of infrared spectroscopy in conjunction with ab initio molecular dynamics simulations. The evolution of the IR spectrum during the reaction has been monitored at 32.2 and 35.5 GPa performing the measurements in a diamond anvil cell. The simulations allowed the characterization of the onset of the high-pressure reaction, showing that its mechanism has a complex bimolecular character and involves the formation of the aci-ion of nitromethane. The growth of a three-dimensional disordered polymer has been evidenced both in the experiments and in the simulations. On decompression of the sample, after the reaction, a continuous evolution of the product is observed with a decomposition into smaller molecules. This behavior has been confirmed by the simulations and represents an important novelty in the scene of the known high-pressure reactions of molecular systems. The major reaction product on decompression is N-methylformamide, the smallest molecule containing the peptide bond. The high-pressure reaction of crystalline nitromethane under irradiation at 458 nm was also experimentally studied. The reaction threshold pressure is significantly lowered by the electronic excitation through two-photon absorption, and methanol, not detected in the purely pressure-induced reaction, is formed. The presence of ammonium carbonate is also observed.

Deformation of volcanic materials by pore pressurization: analog experiments with simplified geometry

NASA Astrophysics Data System (ADS)

Hyman, David; Bursik, Marcus

2018-03-01

The pressurization of pore fluids plays a significant role in deforming volcanic materials; however, understanding of this process remains incomplete, especially scenarios accompanying phreatic eruptions. Analog experiments presented here use a simple geometry to study the mechanics of this type of deformation. Syrup was injected into the base of a sand medium, simulating the permeable flow of fluids through shallow volcanic systems. The experiments examined surface deformation over many source depths and pressures. Surface deformation was recorded using a Microsoft® Kinect™ sensor, generating high-spatiotemporal resolution lab-scale digital elevation models (DEMs). The behavior of the system is controlled by the ratio of pore pressure to lithostatic loading (λ =p/ρ g D). For λ <10, deformation was accommodated by high-angle, reversed-mechanism shearing along which fluid preferentially flowed, leading to a continuous feedback between deformation and pressurization wherein higher pressure ratios yielded larger deformations. For λ >10, fluid expulsion from the layer was much faster, vertically fracturing to the surface with larger pressure ratios yielding less deformation. The temporal behavior of deformation followed a characteristic evolution that produced an approximately exponential increase in deformation with time until complete layer penetration. This process is distinguished from magmatic sources in continuous geodetic data by its rapidity and characteristic time evolution. The time evolution of the experiments compares well with tilt records from Mt. Ontake, Japan, in the lead-up to the deadly 2014 phreatic eruption. Improved understanding of this process may guide the evolution of magmatic intrusions such as dikes, cone sheets, and cryptodomes and contribute to caldera resurgence or deformation that destabilizes volcanic flanks.

Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring

NASA Astrophysics Data System (ADS)

Schwartz, Gregor; Tee, Benjamin C.-K.; Mei, Jianguo; Appleton, Anthony L.; Kim, Do Hwan; Wang, Huiliang; Bao, Zhenan

2013-05-01

Flexible pressure sensors are essential parts of an electronic skin to allow future biomedical prostheses and robots to naturally interact with humans and the environment. Mobile biomonitoring in long-term medical diagnostics is another attractive application for these sensors. Here we report the fabrication of flexible pressure-sensitive organic thin film transistors with a maximum sensitivity of 8.4 kPa-1, a fast response time of <10 ms, high stability over >15,000 cycles and a low power consumption of <1 mW. The combination of a microstructured polydimethylsiloxane dielectric and the high-mobility semiconducting polyisoindigobithiophene-siloxane in a monolithic transistor design enabled us to operate the devices in the subthreshold regime, where the capacitance change upon compression of the dielectric is strongly amplified. We demonstrate that our sensors can be used for non-invasive, high fidelity, continuous radial artery pulse wave monitoring, which may lead to the use of flexible pressure sensors in mobile health monitoring and remote diagnostics in cardiovascular medicine.

Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring.

PubMed

Schwartz, Gregor; Tee, Benjamin C-K; Mei, Jianguo; Appleton, Anthony L; Kim, Do Hwan; Wang, Huiliang; Bao, Zhenan

2013-01-01

Flexible pressure sensors are essential parts of an electronic skin to allow future biomedical prostheses and robots to naturally interact with humans and the environment. Mobile biomonitoring in long-term medical diagnostics is another attractive application for these sensors. Here we report the fabrication of flexible pressure-sensitive organic thin film transistors with a maximum sensitivity of 8.4 kPa(-1), a fast response time of <10 ms, high stability over >15,000 cycles and a low power consumption of <1 mW. The combination of a microstructured polydimethylsiloxane dielectric and the high-mobility semiconducting polyisoindigobithiophene-siloxane in a monolithic transistor design enabled us to operate the devices in the subthreshold regime, where the capacitance change upon compression of the dielectric is strongly amplified. We demonstrate that our sensors can be used for non-invasive, high fidelity, continuous radial artery pulse wave monitoring, which may lead to the use of flexible pressure sensors in mobile health monitoring and remote diagnostics in cardiovascular medicine.

Ab initio study of properties of BaBiO3 at high pressure

NASA Astrophysics Data System (ADS)

Martoňák, Roman; Ceresoli, Davide; Kagayama, Tomoko; Tosatti, Erio

BaBiO3 is a mixed-valence perovskite which escapes metallic state by creating a Bi-O bond disproportionation or CDW pattern, resulting in a Peierls semiconductor with gap of nearly 1 eV at zero pressure. Evolution of structural and electronic properties at high pressure is, however, largely unknown. Pressure, it might be natural to expect, could reduce the bond-disproportionation and bring the system closer to metalicity or even superconductivity. We address this question by ab initio DFT methods based on GGA and hybrid functionals in combination with crystal structure prediction techniques based on genetic algorithms. We analyze the pressure evolution of bond disproportionation as well as other order parameters related to octahedra rotation for various phases in connection with corresponding evolution of the electronic structure. Results indicate that BaBiO3 continues to resist metalization also under pressure, through structural phase transitions which sustain and in fact increase the diversity of length of Bi-O bonds for neighboring Bi ions, in agreement with preliminary high pressure resistivity data. R.M. Slovak Research and Development Agency Contract APVV-15-0496, VEGA project No. 1-0904-15; E.T. ERC MODPHYSFRICT Advanced Grant No. 320796.

Choosing an Oronasal Mask to Deliver Continuous Positive Airway Pressure May Cause More Upper Airway Obstruction or Lead to Higher Continuous Positive Airway Pressure Requirements than a Nasal Mask in Some Patients: A Case Series.

PubMed

Ng, Justin R; Aiyappan, Vinod; Mercer, Jeremy; Catcheside, Peter G; Chai-Coetzer, Ching Li; McEvoy, R Doug; Antic, Nick

2016-09-15

The choice of mask interface used with continuous positive airway pressure (CPAP) therapy can affect the control of upper airway obstruction (UAO) in obstructive sleep apnea (OSA). We describe a case series of four patients with paradoxical worsening of UAO with an oronasal mask and the effect of changing to a nasal mask. We retrospectively reviewed the case histories of 4 patients and recorded patient demographics, in-laboratory and ambulatory CPAP titration data, CPAP therapy data, type of mask interface used and potential confounding factors. The 4 cases (mean ± SD: age = 59 ± 16 y; BMI = 30.5 ± 4.5 kg/m(2)) had a high residual apnoea-hypopnea index (AHI) (43 ± 14.2 events/h) and high CPAP pressure requirements (14.9 ± 6.6 cmH2O) with an oronasal mask. Changing to a nasal mask allowed adequate control of UAO with a significant reduction in the average residual AHI (3.1 ± 1.5 events/h). In two of the four cases, it was demonstrated that control of UAO was obtained at a much lower CPAP pressure compared to the oronasal mask (Case one = 17.5 cmH2O vs 12cmH2O; Case two = 17.9 cmH2O vs 7.8 cmH2O). Other potential confounding factors were unchanged. There are various physiological observations that may explain these findings but it is uncertain which individuals are susceptible to these mechanisms. If patients have OSA incompletely controlled by CPAP with evidence of residual UAO and/or are requiring surprisingly high CPAP pressure to control OSA with an oronasal mask, the choice of mask should be reviewed and consideration be given to a trial of a nasal mask. A commentary on this article appears in this issue on page 1209. © 2016 American Academy of Sleep Medicine.

Continuous flow reduction of artemisinic acid utilizing multi-injection strategies-closing the gap towards a fully continuous synthesis of antimalarial drugs.

PubMed

Pieber, Bartholomäus; Glasnov, Toma; Kappe, C Oliver

2015-03-09

One of the rare alternative reagents for the reduction of carbon-carbon double bonds is diimide (HN=NH), which can be generated in situ from hydrazine hydrate (N2H4⋅H2O) and O2. Although this selective method is extremely clean and powerful, it is rarely used, as the rate-determining oxidation of hydrazine in the absence of a catalyst is relatively slow using conventional batch protocols. A continuous high-temperature/high-pressure methodology dramatically enhances the initial oxidation step, at the same time allowing for a safe and scalable processing of the hazardous reaction mixture. Simple alkenes can be selectively reduced within 10-20 min at 100-120 °C and 20 bar O2 pressure. The development of a multi-injection reactor platform for the periodic addition of N2H4⋅H2O enables the reduction of less reactive olefins even at lower reaction temperatures. This concept was utilized for the highly selective reduction of artemisinic acid to dihydroartemisinic acid, the precursor molecule for the semisynthesis of the antimalarial drug artemisinin. The industrially relevant reduction was achieved by using four consecutive liquid feeds (of N2H4⋅H2O) and residence time units resulting in a highly selective reduction within approximately 40 min at 60 °C and 20 bar O2 pressure, providing dihydroartemisinic acid in ≥93% yield and ≥95% selectivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unexpectedly high pressure for molecular dissociation in liquid hydrogen by electronic simulation.

PubMed

Mazzola, Guglielmo; Yunoki, Seiji; Sorella, Sandro

2014-03-19

The study of the high pressure phase diagram of hydrogen has continued with renewed effort for about one century as it remains a fundamental challenge for experimental and theoretical techniques. Here we employ an efficient molecular dynamics based on the quantum Monte Carlo method, which can describe accurately the electronic correlation and treat a large number of hydrogen atoms, allowing a realistic and reliable prediction of thermodynamic properties. We find that the molecular liquid phase is unexpectedly stable, and the transition towards a fully atomic liquid phase occurs at much higher pressure than previously believed. The old standing problem of low-temperature atomization is, therefore, still far from experimental reach.

Cardiovascular Responses to Sexual Activity in Able-Bodied Individuals and Those Living with Spinal Cord Injury.

PubMed

Davidson, Ross; Elliott, Stacy; Krassioukov, Andrei

2016-12-15

Sexuality is an integral part of the human experience and persists in health and disability. The cardiovascular system is crucial to sexual function and can be affected profoundly by spinal cord injury (SCI). The effects of sexual activity on the cardiovascular system in SCI have not been summarized and compared with sexual activity in able-bodied individuals. A keyword search of Embase, PubMed, and Medline was conducted. From 471 retrieved studies for able-bodied individuals, 11 were included that met the strict criteria of medically uncomplicated participants. In the SCI literature, 117 studies were screened, with 18 meeting criteria. In able-bodied persons, sexual activity resulted in modest increases in systolic blood pressure peaking at orgasm (males of 163 mm Hg and females of 142 mm Hg) and returning to baseline shortly afterward. In persons with SCI, results varied from minimal changes to significant elevations in systolic blood pressure because of episodes of autonomic dysreflexia, especially in those with high thoracic and cervical lesions. Peak systolic blood pressure in these individuals was measured to be as high as 325 mm Hg. In the SCI population, more intense stimuli (including penile vibrostimulation and electroejaculation) tended to result in a greater increase in systolic blood pressure compared with self-stimulation. Studies that used continuous versus intermittent monitoring were more likely to report greater changes in systolic blood pressure. In able-bodied persons, sexual activity results in modest increases in blood pressure. In those with SCI, intense stimulation and higher injury levels result in a higher likelihood of autonomic dysreflexia and elevated blood pressure. Because of rapid changes in blood pressure, continuous monitoring is more advantageous than intermittent measurement, because the latter may miss peak values.

Effect of Sleep Apnea and Continuous Positive Airway Pressure on Cardiac Structure and Recurrence of Atrial Fibrillation

PubMed Central

Neilan, Tomas G.; Farhad, Hoshang; Dodson, John A.; Shah, Ravi V.; Abbasi, Siddique A.; Bakker, Jessie P.; Michaud, Gregory F.; van der Geest, Rob; Blankstein, Ron; Steigner, Michael; John, Roy M.; Jerosch‐Herold, Michael; Malhotra, Atul; Kwong, Raymond Y.

2013-01-01

Background Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI). Methods and Results A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow‐up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence. Conclusions Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI. PMID:24275628

Pressurized tundish for controlling a continuous flow of molten metal

DOEpatents

Lewis, T.W.; Hamill, P.E. Jr.; Ozgu, M.R.; Padfield, R.C.; Rego, D.N.; Brita, G.P.

1990-07-24

A pressurized tundish for controlling a continuous flow of molten metal is characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate. 1 fig.

Solar-Power System Produces High-Pressure Steam

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1985-01-01

Combination of three multistaged solar collectors produces highpressure steam for large-scale continuously operating turbines for generating mechanical or electrical energy. Superheated water vapor drives turbines, attaining an overall system efficiency about 22 percent.

Investigation of the design of a metal-lined fully wrapped composite vessel under high internal pressure

NASA Astrophysics Data System (ADS)

Kalaycıoğlu, Barış; Husnu Dirikolu, M.

2010-09-01

In this study, a Type III composite pressure vessel (ISO 11439:2000) loaded with high internal pressure is investigated in terms of the effect of the orientation of the element coordinate system while simulating the continuous variation of the fibre angle, the effect of symmetric and non-symmetric composite wall stacking sequences, and lastly, a stacking sequence evaluation for reducing the cylindrical section-end cap transition region stress concentration. The research was performed using an Ansys® model with 2.9 l volume, 6061 T6 aluminium liner/Kevlar® 49-Epoxy vessel material, and a service internal pressure loading of 22 MPa. The results show that symmetric stacking sequences give higher burst pressures by up to 15%. Stacking sequence evaluations provided a further 7% pressure-carrying capacity as well as reduced stress concentration in the transition region. Finally, the Type III vessel under consideration provides a 45% lighter construction as compared with an all metal (Type I) vessel.

Magnetic anisotropy at material interfaces

NASA Astrophysics Data System (ADS)

Greene, Peter Kevin

In this dissertation, a comprehensive set of depth dependent magnetic measurements, as well as structural characterizations, were carried out on the Co/Pd multilayer system. The first-order reversal curve (FORC) technique is applied extensively to identify reversal mechanisms and different reversal phases within the material. In particular, the extension of the FORC technique to x-ray magnetic circular dichroism (XMCD) as a surface sensitive technique that identifies reversible magnetization change was performed for the first time. Polarized neutron reflectivity (PNR) was also used to directly measure the magnetization as a function of depth. The effects of deposition pressure grading within the Co/Pd multilayers were investigated. Structures were graded with three distinct pressure regions. FORC analysis shows that not only does increasing the deposition pressure increase the coercivity and effective anisotropy within that region, but also the order in which the pressure is changed also affects the entire structure. Layers grown at high sputtering pressures tend to reverse via domain wall pinning and rotation while those grown at lower pressures reverse via rapid domain wall propagation laterally across the film. Having high pressure layers underneath low pressure layers causes disorder to vertically propagate and lessen the induced anisotropy gradient. This analysis is confirmed by depth dependent magnetization profiles obtain from PNR. Continuously pressure-graded Co/Pd multilayers were then sputtered at two incident angles onto porous aluminum oxide templates with different pore aspect ratios. The effects of pressure grading versus uniform low pressure deposition is studied, as well as the effect of the angle of the incident deposition flux. The coercivity of the pressure graded perpendicular flux sample is compared to the low pressure sample. Additionally the effect of deposition angle and pore sidewall deposition is investigated. It is shown that sidewall deposition strongly affects the reversal behavior. As another way to induce a vertical anisotropy gradient, Co/Pd multilayers were bombarded with Ar+ ions at different energies and fluences. The effects of the depth dependent structural damage as a function of irradiation conditions were investigated. It is shown that the structural damage weakens the perpendicular anisotropy of the surface layers, causing a tilting of the surface magnetic moment into the plane of the film. The surface behavior is explicitly measured and shown to have a significant tilting angle in the top 5 nm depending on irradiation energy and fluence. Continuing the study of vertical anisotropy gradients in Co/Pd multilayers, multilayers with varied Co thickness were studied. Four films with varying Co thickness profiles were created and then patterned into nanodot arrays with diameters between 700 nm and 70 nm. The different films were graded continuously, or in stacks with varying Co thicknesses. An anisotropy gradient is shown to be established in the graded samples, and the switching field is lowered as a result. Furthermore, in the continuously graded samples the magnetization reversal behavior is fundamentally different from all other samples. The thermal energy barriers are measured in the uniform and continuously graded samples, yielding similar results. Finally, the establishment of exchange anisotropy at the ferromagnet / antiferromagnet (FM/AFM) interface in the epitaxial Fe/CoO system is investigated as a function of AFM thickness. The establishment of frozen AFM moments is analyzed using the FORC technique. The FORC technique combined with vector coil measurements also shows the transition from rotatable AFM to pinned AFM moments and suggests a mechanism of winding domain walls within the bulk AFM. (Abstract shortened by UMI.).

A hybrid-drive nonisobaric-ignition scheme for inertial confinement fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, X. T., E-mail: xthe@iapcm.ac.cn; Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871; IFSA Collaborative Innovation Center of MoE, Shanghai Jiao-Tong University, Shanghai 200240

A new hybrid-drive (HD) nonisobaric ignition scheme of inertial confinement fusion (ICF) is proposed, in which a HD pressure to drive implosion dynamics increases via increasing density rather than temperature in the conventional indirect drive (ID) and direct drive (DD) approaches. In this HD (combination of ID and DD) scheme, an assembled target of a spherical hohlraum and a layered deuterium-tritium capsule inside is used. The ID lasers first drive the shock to perform a spherical symmetry implosion and produce a large-scale corona plasma. Then, the DD lasers, whose critical surface in ID corona plasma is far from the radiationmore » ablation front, drive a supersonic electron thermal wave, which slows down to a high-pressure electron compression wave, like a snowplow, piling up the corona plasma into high density and forming a HD pressurized plateau with a large width. The HD pressure is several times the conventional ID and DD ablation pressure and launches an enhanced precursor shock and a continuous compression wave, which give rise to the HD capsule implosion dynamics in a large implosion velocity. The hydrodynamic instabilities at imploding capsule interfaces are suppressed, and the continuous HD compression wave provides main pdV work large enough to hotspot, resulting in the HD nonisobaric ignition. The ignition condition and target design based on this scheme are given theoretically and by numerical simulations. It shows that the novel scheme can significantly suppress implosion asymmetry and hydrodynamic instabilities of current isobaric hotspot ignition design, and a high-gain ICF is promising.« less

Impact of construction and remodeling markets on the U.S. secondary hardwood products industry

Treesearch

Matt Bumgardner; Urs Buehlmann; Al Schuler; Karen Koenig

2011-01-01

The housing correction that started in 2007 continues to run its course. Excessive inventory levels, limited credit availability, and record foreclosure rates continue to have an impact on U.S. housing markets. With inventories high and demand for new construction low, the U.S. hardwood industry's largest markets for appearance-grade products remain under pressure...

The Learning Intention of Low-Qualified Employees: A Key for Participation in Lifelong Learning and Continuous Training

ERIC Educational Resources Information Center

Kyndt, Eva; Govaerts, Natalie; Dochy, Filip; Baert, Herman

2011-01-01

In our continuously changing society, a need for updating one's skills and knowledge puts pressure on safeguarding the labour market position of low-qualified employees. However, prior research and official statistics show that employees with a lower level of education tend to participate less in training than highly-educated individuals. This…

Characterizing the continuously acquired cardiovascular time series during hemodialysis, using median hybrid filter preprocessing noise reduction.

PubMed

Wilson, Scott; Bowyer, Andrea; Harrap, Stephen B

2015-01-01

The clinical characterization of cardiovascular dynamics during hemodialysis (HD) has important pathophysiological implications in terms of diagnostic, cardiovascular risk assessment, and treatment efficacy perspectives. Currently the diagnosis of significant intradialytic systolic blood pressure (SBP) changes among HD patients is imprecise and opportunistic, reliant upon the presence of hypotensive symptoms in conjunction with coincident but isolated noninvasive brachial cuff blood pressure (NIBP) readings. Considering hemodynamic variables as a time series makes a continuous recording approach more desirable than intermittent measures; however, in the clinical environment, the data signal is susceptible to corruption due to both impulsive and Gaussian-type noise. Signal preprocessing is an attractive solution to this problem. Prospectively collected continuous noninvasive SBP data over the short-break intradialytic period in ten patients was preprocessed using a novel median hybrid filter (MHF) algorithm and compared with 50 time-coincident pairs of intradialytic NIBP measures from routine HD practice. The median hybrid preprocessing technique for continuously acquired cardiovascular data yielded a dynamic regression without significant noise and artifact, suitable for high-level profiling of time-dependent SBP behavior. Signal accuracy is highly comparable with standard NIBP measurement, with the added clinical benefit of dynamic real-time hemodynamic information.

High-flow oxygen therapy: pressure analysis in a pediatric airway model.

PubMed

Urbano, Javier; del Castillo, Jimena; López-Herce, Jesús; Gallardo, José A; Solana, María J; Carrillo, Ángel

2012-05-01

The mechanism of high-flow oxygen therapy and the pressures reached in the airway have not been defined. We hypothesized that the flow would generate a low continuous positive pressure, and that elevated flow rates in this model could produce moderate pressures. The objective of this study was to analyze the pressure generated by a high-flow oxygen therapy system in an experimental model of the pediatric airway. An experimental in vitro study was performed. A high-flow oxygen therapy system was connected to 3 types of interface (nasal cannulae, nasal mask, and oronasal mask) and applied to 2 types of pediatric manikin (infant and neonatal). The pressures generated in the circuit, in the airway, and in the pharynx were measured at different flow rates (5, 10, 15, and 20 L/min). The experiment was conducted with and without a leak (mouth sealed and unsealed). Linear regression analyses were performed for each set of measurements. The pressures generated with the different interfaces were very similar. The maximum pressure recorded was 4 cm H(2)O with a flow of 20 L/min via nasal cannulae or nasal mask. When the mouth of the manikin was held open, the pressures reached in the airway and pharynxes were undetectable. Linear regression analyses showed a similar linear relationship between flow and pressures measured in the pharynx (pressure = -0.375 + 0.138 × flow) and in the airway (pressure = -0.375 + 0.158 × flow) with the closed mouth condition. According to our hypothesis, high-flow oxygen therapy systems produced a low-level CPAP in an experimental pediatric model, even with the use of very high flow rates. Linear regression analyses showed similar linear relationships between flow and pressures measured in the pharynx and in the airway. This finding suggests that, at least in part, the effects may be due to other mechanisms.

Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

PubMed

Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

1998-02-20

A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before. Copyright 1998 John Wiley & Sons, Inc.

Sustained Inflation and Its Role in the Delivery Room Management of Preterm Infants.

PubMed

Lista, Gianluca; La Verde, Paola Azzurra; Castoldi, Francesca

2016-01-01

A noninvasive approach in the delivery room in place of intubation and mechanical ventilation can reduce rates of bronchopulmonary dysplasia and death. Nevertheless, the rate of nasal continuous positive airway pressure failure still remains high. In order to prevent lung injury and to enhance the success of continuous positive airway pressure, sustained inflation (administration by face mask or nasopharyngeal tube of a high peak pressure of 20-25 cm H2O, maintained for 10-15 s) has been recently proposed to establish an early and efficient functional residual capacity in the delivery room. Sustained inflation is an intriguing therapy, although the results of clinical trials are controversial in terms of respiratory outcomes. A critical role in the success of sustained inflation could be the presence of open or closed glottis and the contribution of spontaneous breathing that allows air to enter the lungs during the maneuver. Recent neonatal resuscitation guidelines suggest that sustained inflation may be considered in individual clinical circumstances or research settings. © 2016 S. Karger AG, Basel.

Comparison of the effects of continuous positive airway pressure and mandibular advancement devices on sleepiness in patients with obstructive sleep apnoea: a network meta-analysis.

PubMed

Bratton, Daniel J; Gaisl, Thomas; Schlatzer, Christian; Kohler, Malcolm

2015-11-01

Excessive daytime sleepiness is the most important symptom of obstructive sleep apnoea and can affect work productivity, quality of life, and the risk of road traffic accidents. We aimed to quantify the effects of the two main treatments for obstructive sleep apnoea (continuous positive airway pressure and mandibular advancement devices) on daytime sleepiness and to establish predictors of response to continuous positive airway pressure. We searched MEDLINE and the Cochrane Library from inception to May 31, 2015, to identify randomised controlled trials comparing the effects of continuous positive airway pressure, mandibular advancement devices or an inactive control (eg, placebo or no treatment) on the Epworth Sleepiness Scale (ESS, range 0-24 points) in patients with obstructive sleep apnoea. We did a network meta-analysis using multivariate random-effects meta-regression to assess the effect of each treatment on ESS. We used meta-regression to assess the association of the reported effects of continuous positive airway pressure versus inactive controls with the characteristics of trials and their risk of bias. We included 67 studies comprising 6873 patients in the meta-analysis. Compared with an inactive control, continuous positive airway pressure was associated with a reduction in ESS score of 2·5 points (95% CI 2·0-2·9) and mandibular advancement devices of 1·7 points (1·1-2·3). We estimated that, on average, continuous positive airway pressure reduced the ESS score by a further 0·8 points compared with mandibular advancement devices (95% CI 0·1-1·4; p=0·015). However, there was a possibility of publication bias in favour of continuous positive airway pressure that might have resulted in this difference. We noted no evidence that studies reporting higher continuous positive airway pressure adherence also reported larger treatment effects (p=0·70). Continuous positive airway pressure and mandibular advancement devices are effective treatments for reducing daytime sleepiness in patients with obstructive sleep apnoea. Continuous positive airway pressure seemed to be a more effective treatment than mandibular advancement devices, and had an increasingly larger effect in more severe or sleepier obstructive sleep apnoea patients when compared with inactive controls. However, mandibular advancement devices are an effective alternative treatment should continuous positive airway pressure not be tolerated. Swiss National Science Foundation and the University of Zurich Clinical Research Priority Program Sleep and Health. Copyright © 2015 Elsevier Ltd. All rights reserved.

IN VITRO COMPARISON OF MAXIMUM PRESSURE DEVELOPED BY IRRIGATION SYSTEMS IN A KIDNEY MODEL.

PubMed

Proietti, Silvia; Dragos, Laurian; Somani, Bhaskar K; Butticè, Salvatore; Talso, Michele; Emiliani, Esteban; Baghdadi, Mohammed; Giusti, Guido; Traxer, Olivier

2017-04-05

To evaluate in vitro the maximum pressure generated in an artificial kidney model when people of different levels of strengths used various irrigation systems. Fifteen people were enrolled and divided in 3 groups based on their strengths. Individual strength was evaluated according to the maximum pressure each participant was able to achieve using an Encore™ Inflator. The irrigation systems evaluated were: T-FlowTM Dual Port, HilineTM, continuous flow single action pumping system (SAPSTM) with the system close and open, Irri-flo IITM, a simple 60-ml syringe and PeditrolTM . Each irrigation system was connected to URF-V2 ureteroscope, which was inserted into an artificial kidney model. Each participant was asked to produce the maximum pressure possible with every irrigation device. Pressure was measured with the working channel (WC) empty, with a laser fiber and a basket inside. The highest pressure was achieved with the 60 ml-syringe system and the lowest with SAPS continuous version system (with continuous irrigation open), compared to the other irrigation devices (p< 0.0001). Irrespective of the irrigation system, there was a significant difference in the pressure between the WC empty and when occupied with the laser fiber or the basket inside it (p<0.0001). The stratification between the groups showed that the most powerful group could produce the highest pressure in the kidney model with all the irrigation devices in almost any situation. The exception to this was the T-Flow system, which was the only device where no statistical differences were detected among these groups. The use of irrigation systems can often generate excessive pressure in an artificial kidney model, especially with an unoccupied WC of the ureteroscope. Depending on the strength of force applied, very high pressure can be generated by most irrigation devices irrespective of whether the scope is occupied or not.

Hyperbaric hydrothermal atomic force microscope

DOEpatents

Knauss, Kevin G.; Boro, Carl O.; Higgins, Steven R.; Eggleston, Carrick M.

2002-01-01

A hyperbaric hydrothermal atomic force microscope (AFM) is provided to image solid surfaces in fluids, either liquid or gas, at pressures greater than normal atmospheric pressure. The sample can be heated and its surface imaged in aqueous solution at temperatures greater than 100.degree. C. with less than 1 nm vertical resolution. A gas pressurized microscope base chamber houses the stepper motor and piezoelectric scanner. A chemically inert, flexible membrane separates this base chamber from the sample cell environment and constrains a high temperature, pressurized liquid or gas in the sample cell while allowing movement of the scanner. The sample cell is designed for continuous flow of liquid or gas through the sample environment.

Hyperbaric Hydrothermal Atomic Force Microscope

DOEpatents

Knauss, Kevin G.; Boro, Carl O.; Higgins, Steven R.; Eggleston, Carrick M.

2003-07-01

A hyperbaric hydrothermal atomic force microscope (AFM) is provided to image solid surfaces in fluids, either liquid or gas, at pressures greater than normal atmospheric pressure. The sample can be heated and its surface imaged in aqueous solution at temperatures greater than 100.degree. C. with less than 1 nm vertical resolution. A gas pressurized microscope base chamber houses the stepper motor and piezoelectric scanner. A chemically inert, flexible membrane separates this base chamber from the sample cell environment and constrains a high temperature, pressurized liquid or gas in the sample cell while allowing movement of the scanner. The sample cell is designed for continuous flow of liquid or gas through the sample environment.

Verifying Data Integrity of Electronically Scanned Pressure Systems at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Panek, Joseph W.

2001-01-01

The proper operation of the Electronically Scanned Pressure (ESP) System critical to accomplish the following goals: acquisition of highly accurate pressure data for the development of aerospace and commercial aviation systems and continuous confirmation of data quality to avoid costly, unplanned, repeat wind tunnel or turbine testing. Standard automated setup and checkout routines are necessary to accomplish these goals. Data verification and integrity checks occur at three distinct stages, pretest pressure tubing and system checkouts, daily system validation and in-test confirmation of critical system parameters. This paper will give an overview of the existing hardware, software and methods used to validate data integrity.

High-pressure NMR reveals close similarity between cold and alcohol protein denaturation in ubiquitin.

PubMed

Vajpai, Navratna; Nisius, Lydia; Wiktor, Maciej; Grzesiek, Stephan

2013-01-29

Proteins denature not only at high, but also at low temperature as well as high pressure. These denatured states are not easily accessible for experiment, because usually heat denaturation causes aggregation, whereas cold or pressure denaturation occurs at temperatures well below the freezing point of water or pressures above 5 kbar, respectively. Here we have obtained atomic details of the pressure-assisted, cold-denatured state of ubiquitin at 2,500 bar and 258 K by high-resolution NMR techniques. Under these conditions, a folded, native-like and a disordered state exist in slow exchange. Secondary chemical shifts show that the disordered state has structural propensities for a native-like N-terminal β-hairpin and α-helix and a nonnative C-terminal α-helix. These propensities are very similar to the previously described alcohol-denatured (A-)state. Similar to the A-state, (15)N relaxation data indicate that the secondary structure elements move as independent segments. The close similarity of pressure-assisted, cold-denatured, and alcohol-denatured states with native and nonnative secondary elements supports a hierarchical mechanism of folding and supports the notion that similar to alcohol, pressure and cold reduce the hydrophobic effect. Indeed, at nondenaturing concentrations of methanol, a complete transition from the native to the A-state can be achieved at ambient temperature by varying the pressure from 1 to 2,500 bar. The methanol-assisted pressure transition is completely reversible and can also be induced in protein G. This method should allow highly detailed studies of protein-folding transitions in a continuous and reversible manner.

Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

PubMed

Winkler, Bernd E; Muellenbach, Ralf M; Wurmb, Thomas; Struck, Manuel F; Roewer, Norbert; Kranke, Peter

2017-02-01

While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita ® V500, Medumat ® Transport, Oxylator ® EMX, Oxylog ® 2000, Oxylog ® 3000, Primus ® and Servo ® -i as well as the Wenoll ® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat ® ) to 309 ml (Wenoll ® ) and the peak airway pressures from 23 hPa (Primus ® ) to 49 hPa (Oxylog ® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

Understanding Differences in Instructional Quality between High and Lower Value-Added Schools in a Large Urban District

ERIC Educational Resources Information Center

Smith, Thomas M.; Preston, Courtney; Haynes, Katherine Taylor; Booker, Laura Neergaard

2015-01-01

Background/Context: High schools are under increasing pressure to move beyond just graduating students, and many high schools today continue to have low rates of student retention and learning, particularly for students from traditionally low-performing subgroups. Differential dropout rates, wherein low-income students, minorities, and English…

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

High-Pressure Minerals in Meteorites: Constraints on Shock Conditions and Duration

NASA Technical Reports Server (NTRS)

Sharp, Thomas G.

2004-01-01

The objective of this research was to better understand the conditions and duration of shock metamorphism in meteorites through microstructural and microanalytical characterization of high-pressure minerals. A) Continue to investigate the mineralogy and microstructures of melt-veins in a suite of chondritic samples ranging from shock grades S3 through S6 to determine how the mineral assemblages that crystallize at high-pressure and are related to shock grade. B) Investigate the chemical, mineralogical, and microstructural heterogeneities that occur across melt veins to interpret crystallization histories. C) Use static high-pressure experiments to simulate crystallization of melt veins for mineralogical and textural comparisons with the melt veins of naturally shocked samples. D) Characterize the compositions and defect microstructures of polycrystalline ringwoodite, wadsleyite, majorite, (Mg,Fe)Si03-ilmenite and (Mg,Fe)SiO3-perovskite in S6 samples to understand the mechanisms of phase transformations that occur during shock. These results will combined with kinetic data to constrain the time scales of kinetic processes. E) Investigate the transformations of metastable high-pressure minerals back to low- pressure forms to constrain post-shock temperatures and estimates of the peak shock pressure. Of these objectives, we have obtained publishable data on A, B and D. I am currently doing difficult high-pressure melting and quench experiments on an L chondrite known as Mbale. These experiments will provide additional constraints on the mineral assemblages that are produced during rapid quench of an L chondrite at pressures of 16 to 25 GPa. Results from published or nearly published research is presented below. Lists of theses, dissertations and publications are given below.

Linking Metabolism, Elemental Cycles, and Environmental Conditions in the Deep Biosphere: Growth of a Model Extremophile, Archaeoglobus fulgidus, Under High-Pressure Conditions

NASA Astrophysics Data System (ADS)

Oliver, G. C. M.; Cario, A.; Rogers, K. L.

2015-12-01

A majority of Earth's biosphere is hosted in subsurface environments where global-scale biogeochemical and energy cycles are driven by diverse microbial communities that operate on and are influenced by micro-scale environmental variables. While the subsurface hosts a variety of geochemical and geothermal conditions, elevated pressures are common to all subsurface ecosystems. Understanding how microbes adapt to and thrive in high-pressure environments is essential to linking microbial subsurface processes with global-scale cycles. Here we are using a model extremophile, Archaeoglobus fulgidus, to determine how elevated pressures affect the growth, metabolism, and physiology of subsurface microorganisms. A. fulgidus cycles carbon and sulfur via heterotrophic and autotrophic sulfate reduction in various high temperature and high-pressure niches including shallow marine vents, deep-sea hydrothermal vents, and deep oil reservoirs. Here we report the results of A. fulgidus growth experiments at optimum temperature, 83°C, and pressures up to 600 bars. Exponential growth was observed over the entire pressure range, though growth rates were diminished at 500 and 600 bars compared to ambient pressure experimental controls. At pressures up to 400 bars, cell density yields and growth rates were at least as high as ambient pressure controls. Elevated pressures and extended incubation times stimulated cell flocculation, a common stress response in this strain, and cellular morphology was affected at pressures exceeding 400 bars. These results suggest that A. fulgidus continues carbon, sulfur and energy cycling unaffected by elevated pressures up to 400 bars, representing a variety of subsurface environments. The ability of subsurface organisms to drive biogeochemical cycles at elevated pressures is a critical link between the surface and subsurface biospheres and understanding how species-scale processes operate under these conditions is a vital part of global-scale biogeochemical models.

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.

2013-12-01

The high cost of acquiring geodetic data from the sea floor has limited the observations available to help us understand and model the behavior of seafloor geodetic processes. To address this problem, the Pacific GPS Facility at the University of Hawaii is developing a cost effective approach for accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure without the requirement for costly ship time. There is a recognized need to vastly increase our underwater geodetic observing capacity. Most of the largest recorded earthquakes and most devastating tsunamis are generated at subduction zones underwater. Similarly, many volcanoes are partly (e.g. Santorini) or completely (e.g. Loihi) submerged, and are not well observed and understood. Furthermore, landslide features ring many ocean basins, and huge debris deposits surround many volcanic oceanic islands. Our approach will lower the cost of collecting sea-floor geodetic data, reducing the barriers preventing us from acquiring the information we need to observe and understand these types of structures and provide a direct societal benefit in improving hazard assessment. The capability is being developed by equipping one of the University of Hawaii Wave Gliders with an integrated acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, processing unit, and cellular communications. The Wave Glider will interrogate high accuracy pressure sensors on the sea floor to maintain a near-continuous stream of pressure and temperature data, but seafloor pressure data includes contribution from a variety of sources and on its own may not provide the accuracy required for geodetic investigations. Independent measurements of sea surface pressure and sea surface height can be used to remove these contributions from the observed sea floor pressure timeseries. We will integrate our seafloor pressure measurements with air pressure data, and precise vertical measurements of the sea surface from kinematic positioning of the Wave Glider over the bottom sensor, to determine cm-scale vertical seafloor motions. The seafloor package will consist of a simple tripod frame that seats the pressure sensor unit, and includes an attachment onto which an ROV can install a mobile pressure recorder (MPR) should ship and ROV time be available. Two visits with an MPR would allow calibration of the linear drift of the continuous sensor, further enhancing the value of the timeseries. The pressure sensor is recoverable and serviceable and using the MPR calibration will enable the seafloor monument to be re-occupied to extend the pressure record beyond a single 5+ year deployment. We are currently focused on retrieving high accuracy vertical sea floor motions, but, importantly, we have chosen a development approach that provides a simple upgrade path for incorporating the Wave Glider GPS-Acoustic (GPS/A) measurement system under development at SIO. With this upgrade, Wave Gliders could also acquire accurate horizontal motions of the sea floor sensors, and provide a cost-effective way of performing full, 3-dimensional, surveys of sea-floor motions.

High beta plasma operation in a toroidal plasma producing device

DOEpatents

Clarke, John F.

1978-01-01

A high beta plasma is produced in a plasma producing device of toroidal configuration by ohmic heating and auxiliary heating. The plasma pressure is continuously monitored and used in a control system to program the current in the poloidal field windings. Throughout the heating process, magnetic flux is conserved inside the plasma and the distortion of the flux surfaces drives a current in the plasma. As a consequence, the total current increases and the poloidal field windings are driven with an equal and opposing increasing current. The spatial distribution of the current in the poloidal field windings is determined by the plasma pressure. Plasma equilibrium is maintained thereby, and high temperature, high beta operation results.

System and method for continuous solids slurry depressurization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leininger, Thomas Frederick; Steele, Raymond Douglas; Yen, Hsien-Chin William

A continuous slag processing system includes a rotating parallel disc pump, coupled to a motor and a brake. The rotating parallel disc pump includes opposing discs coupled to a shaft, an outlet configured to continuously receive a fluid at a first pressure, and an inlet configured to continuously discharge the fluid at a second pressure less than the first pressure. The rotating parallel disc pump is configurable in a reverse-acting pump mode and a letdown turbine mode. The motor is configured to drive the opposing discs about the shaft and against a flow of the fluid to control a differencemore » between the first pressure and the second pressure in the reverse-acting pump mode. The brake is configured to resist rotation of the opposing discs about the shaft to control the difference between the first pressure and the second pressure in the letdown turbine mode.« less

Cryo-Compression System in a 3000 Ton Multi-Anvil Press

NASA Astrophysics Data System (ADS)

Secco, R. A.; Yong, W.

2016-12-01

Most large volume high pressure devices are capable of high temperature experiments that are typically achieved by using localized resistive heating of a metal foil, graphite or ceramic sleeve inside a thermally insulated sample volume in a high pressure cell. Low temperatures at high pressures are needed for physical property studies of materials that comprise planetary bodies in the outer solar system. However, low temperatures are more difficult to achieve mainly because the massive steel components of the press, which are in good thermal contact with each other under high load, act as large heat reservoirs and pathways that encumber the removal of heat from the pressure cell. We describe a new custom-designed system under development for a 3000 ton multi-anvil press to reach temperatures below 295K at high pressures. The system was designed to remove heat selectively and conductively from the sample volume through six of the eight WC cubes in direct contact with the octahedral pressure cell. Cooling fins made of Cu are sandwiched between, and in thermal contact with, neighboring anvil faces and are each connected to a dedicated Cu heat exchanger chamber through which liquid nitrogen flows. The chamber internal geometry consists of either square pillars that double the internal surface area of the rectangular parallelepiped enclosed volume or continuous walls separated by valleys. Gas from each chamber is vented to the lab through an exhaust pipe. High pressure results will be presented of several temperature monitoring points in the center of the pressure cell and on the surfaces of the WC cubes and steel wedges which recorded the time-dependent cooling progress. Temperature stability tests will also be presented.

Radial to femoral arterial blood pressure differences in septic shock patients receiving high-dose norepinephrine therapy.

PubMed

Kim, Won Young; Jun, Jong Hun; Huh, Jin Won; Hong, Sang Bum; Lim, Chae-Man; Koh, Younsuck

2013-12-01

The accuracy of arterial blood pressure (ABP) monitoring is crucial in treating septic shock patients. Clinically significant differences in central to peripheral ABP could develop into sepsis during vasopressor therapy. The aim of this study was to investigate the difference between radial (peripheral) and femoral (central) ABP in septic shock patients receiving high-dose norepinephrine (NE) therapy. This prospective observational study comparing simultaneous intra-arterial measurements of radial and femoral ABP was performed at a university-affiliated, tertiary referral center between October 2008 and March 2009. Patients with septic shock who needed continuous blood pressure monitoring and high-dose NE therapy 0.1 µg/kg per minute or greater to maintain mean arterial pressure (MAP) of 65 mmHg or greater were included. Statistical analysis was conducted using the Bland-Altman method for comparison of repeated measures. In total, 250 sets of systolic, mean, and diastolic femoral and radial ABP were recorded at baseline and after NE titration. Arterial blood pressure readings from the radial artery were underestimated compared with those from the femoral artery. Overall bias (mean difference between simultaneous measurements) between radial and femoral MAP was +4.9 mmHg; however, during high-dose NE therapy, the bias increased to +6.2 mmHg (95% limits of agreement: -6.0 to +18.3 mmHg). Clinically significant radial-femoral MAP differences (MAP ≥5 mmHg) occurred in up to 62.2% of patients with high-dose NE therapy. Radial artery pressure frequently underestimates central pressure in septic shock patients receiving high-dose NE therapy. Femoral arterial pressure monitoring may be more appropriate when high-dose NE therapy is administered.

An apparatus for altering the mechanical load of the respiratory system.

PubMed

Younes, M; Bilan, D; Jung, D; Kroker, H

1987-06-01

We describe an apparatus for altering the mechanical load against which the respiratory muscles operate in humans. A closed system incorporates a rolling seal spirometer. The spirometer piston shaft is coupled to a fast-responding linear actuator that develops force in proportion to desired command signals. The command signal may be flow (resistive loading or unloading), volume (elastic loading or unloading), constant voltage (continuous positive or negative pressure), or any external function. Combinations of loads can be applied. Logic circuits permit application of the load at specific times during the respiratory cycle, and the magnitude of the loads is continuously adjustable. Maximum pressure output is +/- 20 cmH2O. The apparatus permits loading or unloading over a range of ventilation extending from resting levels to those observed during high levels of exercise (over 100 l/min). In response to a square-wave input, pressure rises exponentially with a time constant of 20 ms.

Continuous particle separation using pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE).

PubMed

Jeon, Hyungkook; Kim, Youngkyu; Lim, Geunbae

2016-01-28

In this paper, we introduce pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE), a novel continuous separation method. In our separation system, the external flow and electric field are applied to particles, such that particle movement is affected by pressure-driven flow, electroosmosis, and electrophoresis. We then analyzed the hydrodynamic drag force and electrophoretic force applied to the particles in opposite directions. Based on this analysis, micro- and nano-sized particles were separated according to their electrophoretic mobilities with high separation efficiency. Because the separation can be achieved in a simple T-shaped microchannel, without the use of internal electrodes, it offers the advantages of low-cost, simple device fabrication and bubble-free operation, compared with conventional μ-FFE methods. Therefore, we expect the proposed separation method to have a wide range of filtering/separation applications in biochemical analysis.

Continuous particle separation using pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE)

PubMed Central

Jeon, Hyungkook; Kim, Youngkyu; Lim, Geunbae

2016-01-01

In this paper, we introduce pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE), a novel continuous separation method. In our separation system, the external flow and electric field are applied to particles, such that particle movement is affected by pressure-driven flow, electroosmosis, and electrophoresis. We then analyzed the hydrodynamic drag force and electrophoretic force applied to the particles in opposite directions. Based on this analysis, micro- and nano-sized particles were separated according to their electrophoretic mobilities with high separation efficiency. Because the separation can be achieved in a simple T-shaped microchannel, without the use of internal electrodes, it offers the advantages of low-cost, simple device fabrication and bubble-free operation, compared with conventional μ-FFE methods. Therefore, we expect the proposed separation method to have a wide range of filtering/separation applications in biochemical analysis. PMID:26819221

Pressure during decision making of continuous sedation in end-of-life situations in Dutch general practice

PubMed Central

2012-01-01

Background Little is known about pressure from patients or relatives on physician’s decision making of continuous palliative sedation. We aim to describe experienced pressure by general practitioners (GPs) in cases of continuous sedation after the introduction of the Dutch practice guideline, using a questionnaire survey. Methods A sample of 918 Dutch GPs were invited to fill out a questionnaire about their last patient under continuous sedation. Cases in which GPs experienced pressure from the patient, relatives or other persons were compared to those without pressure. Results 399 of 918 invite GPs (43%) returned the questionnaire and 250 provided detailed information about their most recent case of continuous sedation. Forty-one GPs (16%) indicated to have experienced pressure from the patient, relatives or colleagues. In GPs younger than 50, guideline knowledge was not related to experienced pressure, whereas in older GPs, 15% with and 36% without guideline knowledge reported pressure. GPs experienced pressure more often when patients had psychological symptoms (compared to physical symptoms only) and when patients had a longer estimated life expectancy. A euthanasia request of the patient coincided with a higher prevalence of pressure for GPs without, but not for GPs with previous experience with euthanasia. GPs who experienced pressure had consulted a palliative consultation team more often than GPs who did not experience pressure. Conclusion One in six GPs felt pressure from patients or relatives to start sedation. This pressure was related to guideline knowledge, especially in older GPs, longer life expectancy and the presence of a euthanasia request, especially for GPs without previous experience of euthanasia. PMID:22759834

CPAP IMPACT: a protocol for a randomised trial of bubble continuous positive airway pressure versus standard care for high-risk children with severe pneumonia using adaptive design methods

PubMed Central

Smith, Andrew G; Eckerle, Michelle; Mvalo, Tisungane; Weir, Brian; Martinson, Francis; Chalira, Alfred; Lufesi, Norman; Mofolo, Innocent; Hosseinipour, Mina

2017-01-01

Introduction Pneumonia is a leading cause of mortality among children in low-resource settings. Mortality is greatest among children with high-risk conditions including HIV infection or exposure, severe malnutrition and/or severe hypoxaemia. WHO treatment recommendations include low-flow oxygen for children with severe pneumonia. Bubble continuous positive airway pressure (bCPAP) is a non-invasive support modality that provides positive end-expiratory pressure and oxygen. bCPAP is effective in the treatment of neonates in low-resource settings; its efficacy is unknown for high-risk children with severe pneumonia in low-resource settings. Methods and analysis CPAP IMPACT is a randomised clinical trial comparing bCPAP to low-flow oxygen in the treatment of severe pneumonia among high-risk children 1–59 months of age. High-risk children are stratified into two subgroups: (1) HIV infection or exposure and/or severe malnutrition; (2) severe hypoxaemia. The trial is being conducted in a Malawi district hospital and will enrol 900 participants. The primary outcome is in-hospital mortality rate of children treated with standard care as compared with bCPAP. Ethics and dissemination CPAP IMPACT has approval from the Institutional Review Boards of all investigators. An urgent need exists to determine whether bCPAP decreases mortality among high-risk children with severe pneumonia to inform resource utilisation in low-resource settings. Trial registration number NCT02484183; Pre-results. PMID:28883928

Project DEEP STEAM

NASA Astrophysics Data System (ADS)

Aeschliman, D. P.; Clay, R. G.; Donaldson, A. B.; Eisenhawer, S. W.; Fox, R. L.; Johnson, D. R.; Mulac, A. J.

1982-01-01

The objective of Project DEEP STEAM is to develop the technology to economically produce heavy oils from deep reservoirs. The tasks included in this project are the development of thermally efficient delivery systems and downhole steam generation systems. During the period January 1-March 31, 1981, effort has continued on a low pressure combustion downhole generator (Rocketdyne), and on two high pressure designs (Foster-Miller Associates, Sandia National Laboratories). The Sandia design was prepared for deployment in the Wilmington Field at Long Beach, California. Progress continued on the Min-Stress II packer concept at L'Garde, Inc., and on the extruded metal packer at Foster-Miller. Initial bare string field data are reported on the insulated tubular test at Lloydminster, Saskatchewan, Canada.

Intermittently-fed high-pressure gasifier process

DOEpatents

Bailey, J.M.; Zadoks, A.L.

1993-11-30

An improved gasifier is described which is adapted for gasifying a predetermined charge of non-gaseous fuel into fuel gas. Each charge of non-gaseous fuel, which may have optional conditioning materials added to it, is intermittently fed to a gasifier chamber where each charge is partially burned with high-pressure air supplied thereto. High-pressure and temperature fuel gas is produced which is cleansed prior to passing out of the gasifier chamber. After gasification of the charge of fuel is ended, the gasifier chamber is vented. The residue of the burned charge in the gasifier chamber is removed, along with the contaminated or reacted conditioning materials, and replaced by a fresh charge. The subject invention provides a feasible way of continuously fueling an internal combustion engine with gasified fuel and is compact enough to be practical for even mobile applications. 3 figures.

Intermittently-fed high-pressure gasifier process

DOEpatents

Bailey, John M.; Zadoks, Abraham L.

1993-11-30

An improved gasifier adapted for gasifying a predetermined charge of non-gaseous fuel into fuel gas. Each charge of non-gaseous fuel, which may have optional conditioning materials added to it, is intermittently fed to a gasifier chamber where each charge is partially burned with high-pressure air supplied thereto. High-pressure and temperature fuel gas is produced which is cleansed prior to passing out of the gasifier chamber. After gasification of the charge of fuel is is ended, the gasifier chamber is vented. The residue of the burned charge in the gasifier chamber is removed, along with the contaminated or reacted conditioning materials, and replaced by a fresh charge. The subject invention provides a feasible way of continuously fueling an internal combustion engine with gasified fuel and is compact enough to be practical for even mobile applications.

Acoustic pressure measurement of pulsed ultrasound using acousto-optic diffraction

NASA Astrophysics Data System (ADS)

Jia, Lecheng; Chen, Shili; Xue, Bin; Wu, Hanzhong; Zhang, Kai; Yang, Xiaoxia; Zeng, Zhoumo

2018-01-01

Compared with continuous ultrasound wave, pulsed ultrasound has been widely used in ultrasound imaging. The aim of this work is to show the applicability of acousto-optic diffraction on pulsed ultrasound transducer. In this paper, acoustic pressure of two ultrasound transducers is measured based on Raman-Nath diffraction. The frequencies of transducers are 5MHz and 10MHz. The pulse-echo method and simulation data are used to evaluate the results. The results show that the proposed method is capable to measure the absolute sound pressure. We get a sectional view of acoustic pressure using a displacement platform as an auxiliary. Compared with the traditional sound pressure measurement methods, the proposed method is non-invasive with high sensitivity and spatial resolution.

Process for the deposition of high temperature stress and oxidation resistant coatings on silicon-based substrates

DOEpatents

Sarin, V.K.

1991-07-30

A process is disclosed for depositing a high temperature stress and oxidation resistant coating on a silicon nitride- or silicon carbide-based substrate body. A gas mixture is passed over the substrate at about 900--1500 C and about 1 torr to about ambient pressure. The gas mixture includes one or more halide vapors with other suitable reactant gases. The partial pressure ratios, flow rates, and process times are sufficient to deposit a continuous, fully dense, adherent coating. The halide and other reactant gases are gradually varied during deposition so that the coating is a graded coating of at least two layers. Each layer is a graded layer changing in composition from the material over which it is deposited to the material of the layer and further to the material, if any, deposited thereon, so that no clearly defined compositional interfaces exist. The gases and their partial pressures are varied according to a predetermined time schedule and the halide and other reactant gases are selected so that the layers include (a) an adherent, continuous intermediate layer about 0.5-20 microns thick of an aluminum nitride or an aluminum oxynitride material, over and chemically bonded to the substrate body, and (b) an adherent, continuous first outer layer about 0.5-900 microns thick including an oxide of aluminum or zirconium over and chemically bonded to the intermediate layer.

Process for the deposition of high temperature stress and oxidation resistant coatings on silicon-based substrates

DOEpatents

Sarin, Vinod K.

1991-01-01

A process for depositing a high temperature stress and oxidation resistant coating on a silicon nitride- or silicon carbide-based substrate body. A gas mixture is passed over the substrate at about 900.degree.-1500.degree. C. and about 1 torr to about ambient pressure. The gas mixture includes one or more halide vapors with other suitable reactant gases. The partial pressure ratios, flow rates, and process times are sufficient to deposit a continuous, fully dense, adherent coating. The halide and other reactant gases are gradually varied during deposition so that the coating is a graded coating of at least two layers. Each layer is a graded layer changing in composition from the material over which it is deposited to the material of the layer and further to the material, if any, deposited thereon, so that no clearly defined compositional interfaces exist. The gases and their partial pressures are varied according to a predetermined time schedule and the halide and other reactant gases are selected so that the layers include (a) an adherent, continuous intermediate layer about 0.5-20 microns thick of an aluminum nitride or an aluminum oxynitride material, over and chemically bonded to the substrate body, and (b) an adherent, continuous first outer layer about 0.5-900 microns thick including an oxide of aluminum or zirconium over and chemically bonded to the intermediate layer.

The phase diagram of high-pressure superionic ice

DOE PAGES

Sun, Jiming; Clark, Bryan K.; Torquato, Salvatore; ...

2015-08-28

Superionic ice is a special group of ice phases at high temperature and pressure, which may exist in ice-rich planets and exoplanets. In superionic ice liquid hydrogen coexists with a crystalline oxygen sublattice. At high pressures, the properties of superionic ice are largely unknown. Here we report evidence that from 280 GPa to 1.3 TPa, there are several competing phases within the close-packed oxygen sublattice. At even higher pressure, the close-packed structure of the oxygen sublattice becomes unstable to a new unusual superionic phase in which the oxygen sublattice takes the P2 1/c symmetry. We also discover that higher pressuremore » phases have lower transition temperatures. The diffusive hydrogen in the P2 1/c superionic phase shows strong anisotropic behaviour and forms a quasi-two-dimensional liquid. The ionic conductivity changes abruptly in the solid to close-packed superionic phase transition, but continuously in the solid to P2 1/c superionic phase transition.« less

Effects of Background Pressure on Relativistic Laser-Plasma Interaction Ion Acceleration

NASA Astrophysics Data System (ADS)

Peterson, Andrew; Orban, C.; Feister, S.; Ngirmang, G.; Smith, J. T.; Klim, A.; Frische, K.; Morrison, J.; Chowdhury, E.; Roquemore, W. M.

2016-10-01

Typically, ultra-intense laser-accelerated ion experiments are carried out under high-vacuum conditions and with a repetition rate up to several shots per day. Looking to the future there is a need to perform these experiments with a much larger repetition rate. A continuously flowing liquid target is more suitable than a solid target for this purpose. However liquids vaporize below their vapor pressure, and the experiment cannot be performed under high-vacuum conditions. The effects of this non-negligible high chamber pressure acceleration of charged particles is not yet well understood. We investigate this phenomena using Particle-in-Cell simulations, exploring the effect of the background pressure on the accelerated ion spectrum. Experiments in this regime are being performed at the Air Force Research Laboratory at Wright-Patterson Air Force Base. This research was sponsored by the Quantum and Non-Equilibrium Processes Division of the Air Force Office of Scientific Research, under the management of Dr. Enrique Parra, Program Manager and significant support from the DOD HPCMP Internship Program.

X-Ray Diffraction on NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eggert, J H; Wark, J

2012-02-15

The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics andmore » techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.« less

High sensitivity pressure transducer based on the phase characteristics of GMI magnetic sensors

NASA Astrophysics Data System (ADS)

Benavides, L. S.; Costa Silva, E.; Costa Monteiro, E.; Hall Barbosa, C. R.

2018-03-01

This paper presents a new configuration for a GMI pressure transducer based on the reading of the phase characteristics of GMI sensor, intended for biomedical applications. The development process of this new class of magnetic field transducers is discussed, beginning with the definition of the ideal conditioning of the GMI sensor elements (dc level and frequency of the excitation current and sample length) and continuing with computational simulations of the full electronic circuit performed using the experimental data obtained from measured GMI curves, and have shown that the improvement in the sensitivity of GMI magnetometers is larger when phase-based transducers are used instead of magnitude-based transducers. Parameters of interest of the developed prototype are thoroughly analyzed, such as: sensitivity, linearity and frequency response. Also, the spectral noise density of the developed pressure transducer is evaluated and its resolution in the passband is estimated. A low-cost GMI pressure transducer was developed, presenting high resolution, high sensitivity and a frequency bandwidth compatible to the desired biomedical applications.

Temperature and volume estimation of under-seafloor fluid from the logging-while-drilling data beneath an active hydrothermal field

NASA Astrophysics Data System (ADS)

Hamada, Y.; Saito, S.; Sanada, Y.; Masaki, Y.; Moe, K.; Kido, Y. N.; Kumagai, H.; Takai, K.; Suzuki, K.

2015-12-01

In July of 2014, offshore drillings on Iheya-North Knoll, Okinawa Trough, was executed as part of Next-generation technology for ocean resources survey, which is a research program in Cross-ministerial Strategic Innovation Promotion Program (SIP). In this expedition, logging-while- drilling (LWD) and measuring-while-drilling (MWD) were inserted into 6 holes (C9011 - C9016) to investigate spatial distribution of hydrothermal deposit and geothermal fluid reservoir. Both of these tools included annular pressure-while-drilling (APWD). Annular pressure and temperature were monitored by the APWD to detect possible exceedingly-high-temperature geofluid. In addition, drilling fluid was continuously circulated at sufficient flow rate to protect LWD tools against high temperature (non-stop driller system). At C9012 and C9016, the LWD tool clearly detected pressure and temperature anomaly at 234 meter below the seafloor (mbsf) and 80 mbsf, respectively. Annular pressure and temperature quickly increases at that depth and it would reflect the injection of high-temperature fluid. During the drilling, however, drilling water was continuously circulated at high flow-rate (2600L/min) and the measured temperature is not exactly in-situ temperature. To investigate the detail of the heat source, such as in-situ temperature and quantity of heat, we performed numerical analyses of thermal fluid and energy-balance assuming injection of high-temperature fluid. We combined pressure loss theory of double cylinders and temperature equation to replicate the fluid flow and its temperature between borehole wall and drilling pipe during the thermofluid injection. As the result, we estimated the temperature and the volume of injected fluid to be 115oC~ and 17.3 m3, respectively (at C9012) from the calculation. This temperature is lower than that of a hydrothermall vent which had been found near the hole (300oC).

Advanced vehicle emission reduction sensor program (FED-SAVER).

DOT National Transportation Integrated Search

2008-09-01

The FED-SAVER program refined and continued the development of an in-cylinder, high temperature pressure sensor by demonstrating that it can be successfully inserted into diesel engines for routine feedback control of each individual cylinder. There ...

77 FR 68185 - Self-Regulatory Organizations; Chicago Stock Exchange, Inc.; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-15

... importance and expense of the Exchange's regulatory efforts and competitive pricing pressures and to ensure... Exchange participates in a highly competitive market in which regulatory costs are continually increasing...

Applying short-duration pulses as a mean to enhance volatile organic compounds removal by air sparging

NASA Astrophysics Data System (ADS)

Ben Neriah, Asaf; Paster, Amir

2017-10-01

Application of short-duration pulses of high air pressure, to an air sparging system for groundwater remediation, was tested in a two-dimensional laboratory setup. It was hypothesized that this injection mode, termed boxcar, can enhance the remediation efficiency due to the larger ZOI and enhanced mixing which results from the pressure pulses. To test this hypothesis, flow and transport experiments were performed. Results confirm that cyclically applying short-duration pressure pulses may enhance contaminant cleanup. Comparing the boxcar to conventional continuous air-injection shows up to a three-fold increase in the single well radius of influence, dependent on the intensity of the short-duration pressure-pulses. The cleanup efficiency of Toluene from the water was 95% higher than that achieved under continuous injection with the same average conditions. This improvement was attributed to the larger zone of influence and higher average air permeability achieved in the boxcar mode, relative to continuous sparging. Mixing enhancement resultant from recurring pressure pulses was suggested as one of the mechanisms which enhance the contaminant cleanup. The application of a boxcar mode in an existing, multiwell, air sparging setup can be relatively straightforward: it requires the installation of an on-off valve in each of the injection-wells and a central control system. Then, turning off some of the wells, for a short-duration, result in a stepwise increase in injection pressure in the rest of the wells. It is hoped that this work will stimulate the additional required research and ultimately a field scale application of this new injection mode.

Synthesis and Raman spectroscopy of a layered SiS2 phase at high pressures

NASA Astrophysics Data System (ADS)

Wang, Yu; Jiang, Shu-Qing; Goncharov, Alexander F.; Gorelli, Federico A.; Chen, Xiao-Jia; Plašienka, Dušan; MartoÅák, Roman; Tosatti, Erio; Santoro, Mario

2018-01-01

Dichalcogenides are known to exhibit layered solid phases, at ambient and high pressures, where 2D layers of chemically bonded formula units are held together by van der Waals forces. These materials are of great interest for solid-state sciences and technology, along with other 2D systems such as graphene and phosphorene. SiS2 is an archetypal model system of the most fundamental interest within this ensemble. Recently, high pressure (GPa) phases with Si in octahedral coordination by S have been theoretically predicted and also experimentally found to occur in this compound. At variance with stishovite in SiO2, which is a 3D network of SiO6 octahedra, the phases with octahedral coordination in SiS2 are 2D layered. Very importantly, this type of semiconducting material was theoretically predicted to exhibit continuous bandgap closing with pressure to a poor metallic state at tens of GPa. We synthesized layered SiS2 with octahedral coordination in a diamond anvil cell at 7.5-9 GPa, by laser heating together elemental S and Si at 1300-1700 K. Indeed, Raman spectroscopy up to 64.4 GPa is compatible with continuous bandgap closing in this material with the onset of either weak metallicity or of a narrow bandgap semiconductor state with a large density of defect-induced, intra-gap energy levels, at about 57 GPa. Importantly, our investigation adds up to the fundamental knowledge of layered dichalcogenides.

Association of Severe Traumatic Brain Injury Patient Outcomes With Duration of Cerebrovascular Autoregulation Impairment Events.

PubMed

Preiksaitis, Aidanas; Krakauskaite, Solventa; Petkus, Vytautas; Rocka, Saulius; Chomskis, Romanas; Dagi, Teodoro Forcht; Ragauskas, Arminas

2016-07-01

Cerebrovascular autoregulation (CA) is an important hemodynamic mechanism that protects the brain against inappropriate fluctuations in cerebral blood flow in the face of changing cerebral perfusion pressure. Temporal CA failure is associated with worse outcomes in various acute neurological diseases. An integrative approach is presently used according to the existing paradigm for the association of series of temporal CA impairments with the outcomes of patients with traumatic brain injury (TBI). To explore the influence of the duration of CA impairment events on severe TBI patient outcomes. Patient age was also included in the analysis of the prospectively collected clinical data. CA monitoring included 33 prospective severe TBI patients. The pressure reactivity index [PRx(t)] was continuously monitored to collect information on the dynamics of CA status and to analyze associations between the duration of the longest CA impairment event and patient outcomes. The Glasgow outcome scale and the duration of the longest CA impairment were negatively correlated. The duration of autoregulation impairment significantly correlated with worse outcomes. Multidimensional representation of Glasgow outcome scale plots showed that better outcomes were obtained for younger patients (age < 47 years) and those whose longest CA impairment event was shorter than 40 minutes if PRx(t) was above 0.7 in the CA impairment event. Unfavorable outcomes for TBI patients are more significantly associated with the duration of the single longest CA impairment episode at a high PRx(t) value, rather than with averaged PRx(t) values or the average time of all CA impairment episodes. ABP, arterial blood pressureABP(t), continuous reference arterial blood pressureCA, cerebrovascular autoregulationCBF, cerebral blood flowCPP, cerebral perfusion pressureGOS, Glasgow outcome scaleGOSHD, Glasgow outcome scale after hospital dischargeGOS6M, Glasgow outcome scale at 6 months after dischargeICP, intracranial pressureICP(t), continuously monitored intracranial pressureLCAI, longest CA impairmentoptCPP, optimal cerebral perfusion pressurePRx(t), pressure reactivity indexTBI, traumatic brain injury.

Non-invasive continuous blood pressure measurement based on mean impact value method, BP neural network, and genetic algorithm.

PubMed

Tan, Xia; Ji, Zhong; Zhang, Yadan

2018-04-25

Non-invasive continuous blood pressure monitoring can provide an important reference and guidance for doctors wishing to analyze the physiological and pathological status of patients and to prevent and diagnose cardiovascular diseases in the clinical setting. Therefore, it is very important to explore a more accurate method of non-invasive continuous blood pressure measurement. To address the shortcomings of existing blood pressure measurement models based on pulse wave transit time or pulse wave parameters, a new method of non-invasive continuous blood pressure measurement - the GA-MIV-BP neural network model - is presented. The mean impact value (MIV) method is used to select the factors that greatly influence blood pressure from the extracted pulse wave transit time and pulse wave parameters. These factors are used as inputs, and the actual blood pressure values as outputs, to train the BP neural network model. The individual parameters are then optimized using a genetic algorithm (GA) to establish the GA-MIV-BP neural network model. Bland-Altman consistency analysis indicated that the measured and predicted blood pressure values were consistent and interchangeable. Therefore, this algorithm is of great significance to promote the clinical application of a non-invasive continuous blood pressure monitoring method.

Characterization of an induced pressure pumping force for microfluidics

NASA Astrophysics Data System (ADS)

Jiang, Hai; Fan, Na; Peng, Bei; Weng, Xuan

2017-05-01

The electro-osmotic pumping and pressure-driven manipulation of fluids are considered as the most common strategies in microfluidic devices. However, both of them exhibit major disadvantages such as hard integration and high reagent consumption, and they are destructive methods for detection and photo bleaching. In this paper, an electric field-effect flow control approach, combining the electro-osmotic pumping force and the pressure-driven pumping force, was developed to generate the induced pressure-driven flow in a T-shaped microfluidic chip. Electro-osmotic flow between the T-intersection and two reservoirs was demonstrated, and it provided a stable, continuous, and electric field-free flow in the section of the microchannel without the electrodes. The velocity of the induced pressure-driven flow was linearly proportional to the applied voltages. Both numerical and experimental investigations were conducted to prove the concept, and the experimental results showed good agreement with the numerical simulations. In comparison to other induced pressure pumping methods, this approach can induce a high and controllable pressure drop in the electric field-free segment, subsequently causing an induced pressure-driven flow for transporting particles or biological cells. In addition, the generation of bubbles and the blocking of the microchannel are avoided.

The combined effect of high pressure and nisin or lysozyme on the inactivation of Alicyclobacillus acidoterrestris spores in apple juice

NASA Astrophysics Data System (ADS)

Sokołowska, B.; Skąpska, S.; Fonberg-Broczek, M.; Niezgoda, J.; Chotkiewicz, M.; Dekowska, A.; Rzoska, S.

2012-03-01

Alicyclobacillus acidoterrestris, a thermoacidophilic and spore-forming bacterium is one of the important target micro-organisms in the quality control of acidic canned foods. High pressure pasteurization (HPP) at 50°C was used for the inactivation of A. acidoterrestris spores in apple juice. Pressure applied both in a continuous and oscillatory mode gave the best results when 200 MPa was used. Increasing the pressure to 500 MPa, as well as lowering its value to 100 MPa, had an adverse effect on the effectiveness of the process. The best results were achieved with the use of a combined treatment, involving oscillatory pressurization at 200 MPa, followed by holding the sample for 60 min at atmospheric pressure and subsequent pressurization at 500 MPa, resulting in a reduction in the spore count of 6.15 log. Nisin significantly enhanced the effect of HPP at 300 MPa. Using pressure of 200 MPa for 45 min with a nisin concentration of 250 IU/mL enabled total spore inactivation (over 6 log). No significant effect of lysozyme at a concentration of 0.05 and 0.1 mg/L at 300 MPa was observed.

Development of a sapphire optical pressure sensor for high-temperature applications

NASA Astrophysics Data System (ADS)

Mills, David A.; Alexander, Dylan; Subhash, Ghatu; Sheplak, Mark

2014-06-01

This paper presents the fabrication, packaging, and characterization of a sapphire optical pressure sensor for hightemperature applications. Currently available instrumentation poses significant limitations on the ability to achieve realtime, continuous measurements in high-temperature environments such as those encountered in industrial gas turbines and high-speed aircraft. The fiber-optic lever design utilizes the deflection of a circular platinum-coated sapphire diaphragm to modulate the light reflected back to a single send/receive sapphire optical fiber. The 7 mm diameter, 50 μm thick diaphragm is attached using a novel thermocompression bonding process based on spark plasma sintering technology. Bonds using platinum as an intermediate layer are achieved at a temperature of 1200°C with a hold time of 5 min. Initial characterization of the bond interface using a simple tensile test indicates a bond strength in excess of 12 MPa. Analysis of the buckled diaphragm after bonding is also presented. The packaged sensor enables continuous operation up to 900°C. Room-temperature characterization reveals a first resonance of 18.2 kHz, a flat-band sensitivity of -130 dB re 1 V/Pa (0.32 μV/Pa) from 4-20 kHz, a minimum detectable pressure of 3.8 Pa, and a linear response up to 169 dB at 1.9 kHz.

Fluidized Bed Membrane Reactors for Ultra Pure H₂ Production--A Step forward towards Commercialization.

PubMed

Helmi, Arash; Fernandez, Ekain; Melendez, Jon; Pacheco Tanaka, David Alfredo; Gallucci, Fausto; van Sint Annaland, Martin

2016-03-19

In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1 Nm³/h of ultra-pure H₂ was designed, built and operated over 900 h of continuous work. Firstly, the performance of the membranes were investigated at different inlet gas compositions and at different temperatures and H₂ partial pressure differences. The membranes showed very high H₂ fluxes (3.89 × 10(-6) mol·m(-2)·Pa(-1)·s(-1) at 400 °C and 1 atm pressure difference) with a H₂/N₂ ideal perm-selectivity (up to 21,000 when integrating five membranes in the module) beyond the DOE 2015 targets. Monitoring the performance of the membranes and the reactor confirmed a very stable performance of the unit for continuous high temperature water gas shift under bubbling fluidization conditions. Several experiments were carried out at different temperatures, pressures and various inlet compositions to determine the optimum operating window for the reactor. The obtained results showed high hydrogen recovery factors, and very low CO concentrations at the permeate side (in average <10 ppm), so that the produced hydrogen can be directly fed to a low temperature PEM fuel cell.

In situ densimetric measurements as a surrogate for suspended-sediment concentrations in the Rio Puerco, New Mexico

USGS Publications Warehouse

Brown, Jeb E.; Gray, John R.; Hornewer, Nancy J.

2015-01-01

Surrogate measurements of suspended-sediment concentration (SSC) are increasingly used to provide continuous, high-resolution, and demonstrably accurate data at a reasonable cost. Densimetric data, calculated from the difference between two in situ pressure measurements, exploit variations in real-time streamflow densities to infer SSCs. Unlike other suspendedsediment surrogate technologies based on bulk or digital optics, laser, or hydroacoustics, the accuracy of SSC data estimated using the pressure-difference (also referred to as densimetric) surrogate technology theoretically improves with increasing SCCs. Coupled with streamflow data, continuous suspended-sediment discharges can be calculated using SSC data estimated in real-time using the densimetric technology. The densimetric technology was evaluated at the Rio Puerco in New Mexico, a stream where SSC values regularly range from 10,000-200,000 milligrams per liter (mg/L) and have exceeded 500,000 mg/L. The constant-flow dual-orifice bubbler measures pressure using two precision pressure-transducer sensors at vertically aligned fixed locations in a water column. Water density is calculated from the temperature-compensated differential pressure and SSCs are inferred from the density data. A linear regression model comparing density values to field-measured SSC values yielded an R² of 0.74. Although the application of the densimetric surrogate is likely limited to fluvial systems with SSCs larger than about 10,000 mg/L, based on this and previous studies, the densimetric technology fills a void for monitoring streams with high SSCs.

Stress and Job Satisfaction among Secondary School Principals in Texas

ERIC Educational Resources Information Center

Romney, Angela G.

2012-01-01

The role of a secondary school principal continues to expand and increase principals' daily workload. The high stakes testing environment also places pressure on principals to ensure that students score high on standardized tests. With a heavy workload, principals find themselves faced with numerous work-related stressors that influence job…

49 CFR Appendix B to Part 195 - Risk-Based Alternative to Pressure Testing Older Hazardous Liquid and Carbon Dioxide Pipelines

Code of Federal Regulations, 2014 CFR

2014-10-01

...) (Propane, butane, Natural Gas Liquid (NGL), ammonia) Highly toxic (Benzene, high Hydrogen Sulfide content... Hazardous Liquid and Carbon Dioxide Pipelines B Appendix B to Part 195 Transportation Other Regulations... OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pt. 195...

49 CFR Appendix B to Part 195 - Risk-Based Alternative to Pressure Testing Older Hazardous Liquid and Carbon Dioxide Pipelines

Code of Federal Regulations, 2012 CFR

2012-10-01

...) (Propane, butane, Natural Gas Liquid (NGL), ammonia) Highly toxic (Benzene, high Hydrogen Sulfide content... Hazardous Liquid and Carbon Dioxide Pipelines B Appendix B to Part 195 Transportation Other Regulations... OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pt. 195...

49 CFR Appendix B to Part 195 - Risk-Based Alternative to Pressure Testing Older Hazardous Liquid and Carbon Dioxide Pipelines

Code of Federal Regulations, 2011 CFR

2011-10-01

...) (Propane, butane, Natural Gas Liquid (NGL), ammonia) Highly toxic (Benzene, high Hydrogen Sulfide content... Hazardous Liquid and Carbon Dioxide Pipelines B Appendix B to Part 195 Transportation Other Regulations... OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pt. 195...

49 CFR Appendix B to Part 195 - Risk-Based Alternative to Pressure Testing Older Hazardous Liquid and Carbon Dioxide Pipelines

Code of Federal Regulations, 2013 CFR

2013-10-01

...) (Propane, butane, Natural Gas Liquid (NGL), ammonia) Highly toxic (Benzene, high Hydrogen Sulfide content... Hazardous Liquid and Carbon Dioxide Pipelines B Appendix B to Part 195 Transportation Other Regulations... OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pt. 195...

49 CFR Appendix B to Part 195 - Risk-Based Alternative to Pressure Testing Older Hazardous Liquid and Carbon Dioxide Pipelines

Code of Federal Regulations, 2010 CFR

2010-10-01

...) (Propane, butane, Natural Gas Liquid (NGL), ammonia) Highly toxic (Benzene, high Hydrogen Sulfide content... Hazardous Liquid and Carbon Dioxide Pipelines B Appendix B to Part 195 Transportation Other Regulations... OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pt. 195...

Constructing Global Competence through Relationship Building in Mexican High Schools

ERIC Educational Resources Information Center

Petro, Lisa; Garin, Maria Jose Pineda

2017-01-01

As globalization speeds forward, there is immense pressure on school systems to keep up with the changing world. School leaders and teachers must continuously reevaluate their students' needs and consider the forces that will shape their futures. Learn how a dynamic, multi-campus high school in Mexico reimagined its approach to global competence…

Effects of different computer typing speeds on acceleration and peak contact pressure of the fingertips during computer typing.

PubMed

Yoo, Won-Gyu

2015-01-01

[Purpose] This study showed the effects of different computer typing speeds on acceleration and peak contact pressure of the fingertips during computer typing. [Subjects] Twenty-one male computer workers voluntarily consented to participate in this study. They consisted of 7 workers who could type 200-300 characteristics/minute, 7 workers who could type 300-400 characteristics/minute, and 7 workers who could type 400-500 chracteristics/minute. [Methods] This study was used to measure the acceleration and peak contact pressure of the fingertips for different typing speed groups using an accelerometer and CONFORMat system. [Results] The fingertip contact pressure was increased in the high typing speed group compared with the low and medium typing speed groups. The fingertip acceleration was increased in the high typing speed group compared with the low and medium typing speed groups. [Conclusion] The results of the present study indicate that a fast typing speed cause continuous pressure stress to be applied to the fingers, thereby creating pain in the fingers.

Study on Transfer Rules of Coal Reservoir Pressure Drop Based on Coalbed Methane Well Drainage Experiments

NASA Astrophysics Data System (ADS)

Yuhang, X.

2017-12-01

A pumping test was carried out to explore the transfer rules of pressure drop in coal reservoir during the drainage. The experiment was divided into three stages. In the first stage, the pump displacement of 3m3/h was used to reduce the bottom hole flowing pressure and stopped until the continuous gas phase was produced; Undertaking the first stage, in the second stage, when the gas phase was continuously produced, the pump was stopped immediately. As the bottom hole flowing pressure going up without gas phase, pumping started again for a week. In the third stage ,the well pumping was carried out at the bottom hole pressure drop rate of 30Kpa/d after two months' recovery. Combined with the data of regional geology and fractured well, taking the characteristics of macroscopic coal rocks, development of pore and fracture in coal and isothermal adsorption test as the background, the features of reservoir output in each stage of the experiment were analyzed and compared, and then the transfer rules of pressure drop contained in the differences of the output was studied further. In the first and third stage of the experiment, the output of liquid phase was much larger than the space volume of coal reservoir pore and fracture in the range of 100m2. In the second stage, the output of the continuous gas phase appeared around 0.7Mpa when the continuous gas phase appears below the critical desorption pressure of 0.25Mpa during the whole experiment. The results indicate that, the transfer of pressure drop in the coal reservoir of this well is mainly horizontal, and the liquid phase produced in the reservoir mainly comes from the recharge of the reservoir at the far end of the relative high pressure area; the adsorption space of coalbed methane in the coal matrix as well as the main migration channel of fluid in the reservoir doesn't belong to the same pressure system and there exists the communication barrier between them. In addition, the increasing of the effective stress has little influence on the communication between these two systems. The definition of transfer rules in coal reservoir pressure drop, also the understanding of the correlation between the rules and characteristics of the reservoir output has great guiding significance to the establishment of pressure drop system in coalbed methane well as well as the analysis of production problems.

Effects of a high-intensity interval training program versus a moderate-intensity continuous training program on maximal oxygen uptake and blood pressure in healthy adults: study protocol for a randomized controlled trial.

PubMed

Arboleda Serna, Víctor Hugo; Arango Vélez, Elkin Fernando; Gómez Arias, Rubén Darío; Feito, Yuri

2016-08-18

Participation in aerobic exercise generates increased cardiorespiratory fitness, which results in a protective factor for cardiovascular disease and all-cause mortality. High-intensity interval training might cause higher increases in cardiorespiratory fitness in comparison with moderate-intensity continuous training; nevertheless, current evidence is not conclusive. To our knowledge, this is the first study to test the effect of high-intensity interval training with total load duration of 7.5 min per session. A randomized controlled trial will be performed on two groups of healthy, sedentary male volunteers (n = 44). The study protocol will include 24 exercise sessions, three times a week, including aerobic training on a treadmill and strength training exercises. The intervention group will perform 15 bouts of 30 s, each at an intensity between 90 % and 95 % of maximal heart rate. The control group will complete 40 min of continuous exercise, ranging between 65 % and 75 % of maximal heart rate. The primary outcome measure to be evaluated will be maximal oxygen uptake (VO2max), and systolic and diastolic blood pressure will be evaluated as secondary outcome measures. Waist circumference, body mass index, and body composition will also be evaluated. Epidemiological evidence shows the link between VO2max and its association with chronic conditions that trigger CVD. Therefore, finding ways to improve VO2max and reduce blood pressure it is of vital importance to public health. NCT02288403 . Registered on 4 November 2014.

Continuous-Reading Cryogen Level Sensor

NASA Technical Reports Server (NTRS)

Barone, F. E.; Fox, E.; Macumber, S.

1984-01-01

Two pressure transducers used in system for measuring amount of cryogenic liquid in tank. System provides continuous measurements accurate within 0.03 percent. Sensors determine pressure in liquid and vapor in tank. Microprocessor uses pressure difference to compute mass of cryogenic liquid in tank. New system allows continuous sensing; unaffected by localized variations in composition and density as are capacitance-sensing schemes.

Continuous Blood Pressure Monitoring in Daily Life

NASA Astrophysics Data System (ADS)

Lopez, Guillaume; Shuzo, Masaki; Ushida, Hiroyuki; Hidaka, Keita; Yanagimoto, Shintaro; Imai, Yasushi; Kosaka, Akio; Delaunay, Jean-Jacques; Yamada, Ichiro

Continuous monitoring of blood pressure in daily life could improve early detection of cardiovascular disorders, as well as promoting healthcare. Conventional ambulatory blood pressure monitoring (ABPM) equipment can measure blood pressure at regular intervals for 24 hours, but is limited by long measuring time, low sampling rate, and constrained measuring posture. In this paper, we demonstrate a new method for continuous real-time measurement of blood pressure during daily activities. Our method is based on blood pressure estimation from pulse wave velocity (PWV) calculation, which formula we improved to take into account changes in the inner diameter of blood vessels. Blood pressure estimation results using our new method showed a greater precision of measured data during exercise, and a better accuracy than the conventional PWV method.

Miniature Piezoelectric Compressor for Joule-Thomson Cryocoolers

NASA Astrophysics Data System (ADS)

Sobol, Sergey; Tzabar, Nir; Grossman, Gershon

Joule-Thomson (JT) cryocoolers operate with a continuous flow of the working fluid that enters the cooler at a high pressure and leaves it at a lower pressure. Ideally, the temperature of the outgoing fluid equals the temperature of the entering fluid. JT cryocoolers that operate with pure refrigerants require high pressure of a few tens of MPa where the low pressure is usually around 0.1 MPa. Circulation of the working fluid in such cases requires high pressure ratio compressors that evidently have large dimensions. JT cryocoolers can operate with much lower pressure ratios by using mixed-refrigerants. Cooling from 300 K to about 80 K in a single stage cryocooler normally requires a pressure ratio of about 1:25. In the present research a miniature compressor driven by piezoelectric elements is developed in collaboration between Rafael and the Technion. This type of compressor has the advantage of improved long life compared to other mechanical compressors, very low vibrations, and silent operation. In the current case, the design goal of the intake and discharge pressures has been 0.1 and 2.5 MPa, respectively, with a flow rate of 0.06 g/s. The compressor has two compression stages; 1:5 and 5:25. Several configurations have been considered, fabricated, and tested. The performance of the last configuration approaches the desired specification and is presented in the current paper together with the design concept.

Regulated-current dc power supply for gaseous-discharge lamps

NASA Technical Reports Server (NTRS)

Freeman, W.; Huguenin, D.

1970-01-01

Controlled current source having a high output resistance feeds continuous-flow hydrogen lamps in vacuum-ultraviolet photometric equipment. The power supply, also used with low-pressure sealed lamps, has a short recovery time and smooth regulation without overshoot.

Acoustic wave propagation in high-pressure system.

PubMed

Foldyna, Josef; Sitek, Libor; Habán, Vladimír

2006-12-22

Recently, substantial attention is paid to the development of methods of generation of pulsations in high-pressure systems to produce pulsating high-speed water jets. The reason is that the introduction of pulsations into the water jets enables to increase their cutting efficiency due to the fact that the impact pressure (so-called water-hammer pressure) generated by an impact of slug of water on the target material is considerably higher than the stagnation pressure generated by corresponding continuous jet. Special method of pulsating jet generation was developed and tested extensively under the laboratory conditions at the Institute of Geonics in Ostrava. The method is based on the action of acoustic transducer on the pressure liquid and transmission of generated acoustic waves via pressure system to the nozzle. The purpose of the paper is to present results obtained during the research oriented at the determination of acoustic wave propagation in high-pressure system. The final objective of the research is to solve the problem of transmission of acoustic waves through high-pressure water to generate pulsating jet effectively even at larger distances from the acoustic source. In order to be able to simulate numerically acoustic wave propagation in the system, it is necessary among others to determine dependence of the sound speed and second kinematical viscosity on operating pressure. Method of determination of the second kinematical viscosity and speed of sound in liquid using modal analysis of response of the tube filled with liquid to the impact was developed. The response was measured by pressure sensors placed at both ends of the tube. Results obtained and presented in the paper indicate good agreement between experimental data and values of speed of sound calculated from so-called "UNESCO equation". They also show that the value of the second kinematical viscosity of water depends on the pressure.

Fuel Line Based Acoustic Flame-Out Detection System

NASA Technical Reports Server (NTRS)

Puster, Richard L. (Inventor); Franke, John M. (Inventor)

1997-01-01

An acoustic flame-out detection system that renders a large high pressure combustor safe in the event of a flame-out and possible explosive reignition. A dynamic pressure transducer is placed in the fuel and detects the stabilizing fuel pressure oscillations, caused by the combustion process. An electric circuit converts the signal from the combustion vortices, and transmitted to the fuel flow to a series of pulses. A missing pulse detector counts the pulses and continuously resets itself. If three consecutive pulses are missing, the circuit closes the fuel valve. With fuel denied the combustor is shut down or restarted under controlled conditions.

An Autonomous, Low Cost Platform for Seafloor Geodetic Observations

NASA Astrophysics Data System (ADS)

Ericksen, T.; Foster, J. H.; Bingham, B. S.; Oshiro, J.

2015-12-01

The Pacific GPS Facility and the Field Robotics Laboratory at the University of Hawaii have developed an approach to significantly reduce the costs of accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure. Traditional ship-based methods of acquiring these measurements are often prohibitively expensive. Our goal has been to reduce the primary barrier preventing us from acquiring the observations we need to understand geodetic processes, and the hazards they present, at subduction zones, submarine volcanoes, and subsea landslides. To this end, we have designed a payload package for the University of Hawaii Wave Glider which incorporates an acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, meteorological sensors, processing computer, and cellular communications. The Wave Glider is able to interrogate high accuracy pressure sensors on the seafloor to maintain a near-continuous stream of ocean bottom pressure and temperature data. The Wave Glider also functions as an integral part of the seafloor geodetic observing system, recording accurate sea surface elevations and barometric pressure; direct measurements of two of the primary sources of seafloor pressure change. The seafloor geodetic monument seats a sensor capable of recording pressure, temperature, and sound velocity for a deployment duration of over 5 years with an acoustic modem for communications, and an integral acoustic release for recovery and replacement of batteries. The design of the geodetic monument allows for precise repositioning of the sensor to extend the pressure record beyond a single 5+ year deployment, and includes the capability to install a mobile pressure recorder for calibration of the linear drift of the continuous pressure sensor. We will present the results of our field tests and an assessment of our ability to determine cm-scale vertical seafloor motions by integrating our seafloor pressure measurements with the independent Wave Glider measurements of sea surface pressure and sea surface height. An overall summary of the performance and costs of making seafloor geodetic measurement with this system will be provided.

Pressure-induced densification in GeO{sub 2} glass: A transmission x-ray microscopy study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yu, E-mail: lyforest@stanford.edu; Zeng, Qiaoshi; Yang, Wenge

2013-12-23

Nanoscale transmission x-ray microscopy measurements have been performed to determine the effect of pressure (P) on the volume (V) change in GeO{sub 2} glass up to 38.5 GPa. The P-V data show a continuous increase upon compression, indicating that the density-driven structural transformation is a gradual process. Over the pressure range studied, a transition is observed at approximately 10–13 GPa, where the material displays distinct compression behaviors. The pressure-induced densification that involves the coordination number change has been discussed. Using this newly developed high-pressure imaging technique with tens of nanometer resolution, we have provided a direct and unequivocal way for measuring densitymore » of amorphous materials to much higher pressures with accuracy rivaling x-ray diffraction of crystalline solids.« less

Lagrangian technique to calculate window interface velocity from shock velocity measurements: Application for quartz windows

DOE PAGES

McCoy, Chad A.; Knudson, Marcus D.

2017-08-24

Measurement of the window interface velocity is a common technique for investigating the dynamic response materials at high strain rates. However, these measurements are limited in pressure to the range where the window remains transparent. The most common window material for this application is lithium fluoride, which under single shock compression becomes opaque at ~200 GPa. To date, no other window material has been identified for use at higher pressures. Here, we present a Lagrangian technique to calculate the interface velocity from a continuously measured shock velocity, with application to quartz. The quartz shock front becomes reflective upon melt, atmore » ~100 GPa, enabling the use of velocity interferometry to continuously measure the shock velocity. This technique overlaps with the range of pressures accessible with LiF windows and extends the region where wave profile measurements are possible to pressures in excess of 2000 GPa. Lastly, we show through simulated data that the technique accurately reproduces the interface velocity within 20% of the initial state, and that the Lagrangian technique represents a significant improvement over a simple linear approximation.« less

Lagrangian technique to calculate window interface velocity from shock velocity measurements: Application for quartz windows

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCoy, Chad A.; Knudson, Marcus D.

Measurement of the window interface velocity is a common technique for investigating the dynamic response materials at high strain rates. However, these measurements are limited in pressure to the range where the window remains transparent. The most common window material for this application is lithium fluoride, which under single shock compression becomes opaque at ~200 GPa. To date, no other window material has been identified for use at higher pressures. Here, we present a Lagrangian technique to calculate the interface velocity from a continuously measured shock velocity, with application to quartz. The quartz shock front becomes reflective upon melt, atmore » ~100 GPa, enabling the use of velocity interferometry to continuously measure the shock velocity. This technique overlaps with the range of pressures accessible with LiF windows and extends the region where wave profile measurements are possible to pressures in excess of 2000 GPa. Lastly, we show through simulated data that the technique accurately reproduces the interface velocity within 20% of the initial state, and that the Lagrangian technique represents a significant improvement over a simple linear approximation.« less

Randomized clinical trial to compare negative-pressure wound therapy approaches with low and high pressure, silicone-coated dressing, and polyurethane foam dressing.

PubMed

Lavery, Lawrence A; La Fontaine, Javier; Thakral, Gaurav; Kim, Paul J; Bhavan, Kavita; Davis, Kathryn E

2014-03-01

This study was designed to compare two approaches to negative-pressure wound therapy: 125-mmHg pressure with a polyurethane foam dressing and 75-mmHg pressure with a silicone-coated dressing. Forty patients with diabetic foot wounds, after incision and drainage or amputation for infection, were assigned randomly to negative-pressure wound therapy with 75-mmHg continuous pressure with a silicone-covered dressing (75-mmHg group) or 125-mmHg with a polyurethane foam dressing (125-mmHg group) for up to 4 weeks or until surgical closure. There was no difference in the proportion of wounds that were closed surgically (75-mmHg group, 50 percent; 125-mmHg group, 60 percent), wounds that demonstrated 50 percent wound area reduction (75-mmHg group, 65 percent; 125-mmHg group, 80 percent), or wounds that demonstrated 50 percent wound volume reduction after 4 weeks of therapy (75-mmHg group, 95 percent; 125-mmHg group, 90 percent). The authors' results suggest that there was no difference in outcomes in wounds treated with low pressure (75 mmHg) with a silicone-coated interface and high pressure (125 mmHg) with a polyurethane foam interface. Therapeutic, II.

40 CFR 147.1803 - Existing Class I and III wells authorized by rule-maximum injection pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... authorized by rule-maximum injection pressure. 147.1803 Section 147.1803 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) STATE, TRIBAL, AND EPA-ADMINISTERED...—maximum injection pressure. The owner or operator shall limit injection pressure to the lesser of: (a) A...

System and method for slurry handling

DOEpatents

Steele, Raymond Douglas; Oppenheim, Judith Pauline

2015-12-29

A system includes a slurry depressurizing system that includes a liquid expansion system configured to continuously receive a slurry at a first pressure and continuously discharge the slurry at a second pressure. For example, the slurry depressurizing system may include an expansion turbine to expand the slurry from the first pressure to the second pressure.

High pressure as a probe of the solid state

NASA Astrophysics Data System (ADS)

Ruoff, Arthur L.

1994-07-01

It is a great pleasure and honor to receive the Percy Williams Bridgman Award. Henry Eyring, my Ph.D. advisor, instilled in me a desire to unravel the secrets of nature in the chemical and physical world. He continued what my mother had begun. From my father I learned the virtue and satisfaction of hard work. In reading Percy Bridgman's The Physics of High Pressure [1] after I came to Cornell, I became intrigued by the high-pressure variable, so I owe much to him. I received valuable assistance and encouragement from George Kennedy and Harry Drickamer (the first winner of the Bridgman Award) and later from Alvin Van Valkenburg (a co-inventor with three others of the diamond anvil cell). Most importantly, I received encouragement from my wife, Enid Seaton Ruoff, to carry out what is sometimes the arduous pursuit of science—a pursuit that involves long working hours—and I want especially to thank her.

Continuous versus intermittent endotracheal cuff pressure control for the prevention of ventilator-associated respiratory infections in Vietnam: study protocol for a randomised controlled trial.

PubMed

Dat, Vu Quoc; Geskus, Ronald B; Wolbers, Marcel; Loan, Huynh Thi; Yen, Lam Minh; Binh, Nguyen Thien; Chien, Le Thanh; Mai, Nguyen Thi Hoang; Phu, Nguyen Hoan; Lan, Nguyen Phu Huong; Hao, Nguyen Van; Long, Hoang Bao; Thuy, Tran Phuong; Kinh, Nguyen Van; Trung, Nguyen Vu; Phu, Vu Dinh; Cap, Nguyen Trung; Trinh, Dao Tuyet; Campbell, James; Kestelyn, Evelyne; Wertheim, Heiman F L; Wyncoll, Duncan; Thwaites, Guy Edward; van Doorn, H Rogier; Thwaites, C Louise; Nadjm, Behzad

2018-04-04

Ventilator-associated respiratory infection (VARI) comprises ventilator-associated pneumonia (VAP) and ventilator-associated tracheobronchitis (VAT). Although their diagnostic criteria vary, together these are the most common hospital-acquired infections in intensive care units (ICUs) worldwide, responsible for a large proportion of antibiotic use within ICUs. Evidence-based strategies for the prevention of VARI in resource-limited settings are lacking. Preventing the leakage of oropharyngeal secretions into the lung using continuous endotracheal cuff pressure control is a promising strategy. The aim of this study is to investigate the efficacy of automated, continuous endotracheal cuff pressure control in preventing the development of VARI and reducing antibiotic use in ICUs in Vietnam. This is an open-label randomised controlled multicentre trial. We will enrol 600 adult patients intubated for ≤ 24 h at the time of enrolment. Eligible patients will be stratified according to admission diagnosis (180 tetanus, 420 non-tetanus) and site and will be randomised in a 1:1 ratio to receive either (1) automated, continuous control of endotracheal cuff pressure or (2) intermittent measurement and control of endotracheal cuff pressure using a manual cuff pressure meter. The primary outcome is the occurrence of VARI, defined as either VAP or VAT during the ICU admission up to a maximum of 90 days after randomisation. Patients in both groups who are at risk for VARI will receive a standardised battery of investigations if their treating physician feels a new infection has occurred, the results of which will be used by an endpoint review committee, blinded to the allocated arm and independent of patient care, to determine the primary outcome. All enrolled patients will be followed for mortality and endotracheal tube cuff-related complications at 28 days and 90 days after randomisation. Other secondary outcomes include antibiotic use; days ventilated, in ICU and in hospital; inpatient mortality; costs of antibiotics in ICU; duration of ICU stay; and duration of hospital stay. This study will provide high-quality evidence concerning the use of continuous endotracheal cuff pressure control as a method to reduce VARI, antibiotic use and hospitalisation costs and to shorten stay. ClinicalTrials.gov, NCT02966392 . Registered on November 9, 2016. Protocol version: 2.0; issue date March 3, 2017.

Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

PubMed

Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

2016-01-01

The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

Bubbles are responsive materials interesting for nonequilibrium physics

NASA Astrophysics Data System (ADS)

Andreeva, Daria; Granick, Steve

Understanding of nature and conditions of non-equilibrium transformations of bubbles, droplets, polysomes and vesicles in a gradient filed is a breath-taking question that dissipative systems raise. We ask: how to establish a dynamic control of useful characteristics, for example dynamic control of morphology and composition modulation in soft matter. A possible answer is to develop a new generation of dynamic impactors that can trigger spatiotemporal oscillations of structures and functions. We aim to apply acoustic filed for development of temperature and pressure oscillations at a microscale area. We demonstrate amazing dynamic behavior of gas-filled bubbles in pressure gradient field using a unique technique combining optical imaging, high intensity ultrasound and high speed camera. We find that pressure oscillations trigger continuous phase transformations that are considered to be impossible in physical systems.

Autonomic Impairment in Severe Traumatic Brain Injury: A Multimodal Neuromonitoring Study.

PubMed

Sykora, Marek; Czosnyka, Marek; Liu, Xiuyun; Donnelly, Joseph; Nasr, Nathalie; Diedler, Jennifer; Okoroafor, Francois; Hutchinson, Peter; Menon, David; Smielewski, Peter

2016-06-01

Autonomic impairment after acute traumatic brain injury has been associated independently with both increased morbidity and mortality. Links between autonomic impairment and increased intracranial pressure or impaired cerebral autoregulation have been described as well. However, relationships between autonomic impairment, intracranial pressure, impaired cerebral autoregulation, and outcome remain poorly explored. Using continuous measurements of heart rate variability and baroreflex sensitivity we aimed to test whether autonomic markers are associated with functional outcome and mortality independently of intracranial variables. Further, we aimed to evaluate the relationships between autonomic functions, intracranial pressure, and cerebral autoregulation. Retrospective analysis of a prospective database. Neurocritical care unit in a university hospital. Sedated patients with severe traumatic brain injury. Waveforms of intracranial pressure and arterial blood pressure, baseline Glasgow Coma Scale and 6 months Glasgow Outcome Scale were recorded. Baroreflex sensitivity was assessed every 10 seconds using a modified cross-correlational method. Frequency domain analyses of heart rate variability were performed automatically every 10 seconds from a moving 300 seconds of the monitoring time window. Mean values of baroreflex sensitivity, heart rate variability, intracranial pressure, arterial blood pressure, cerebral perfusion pressure, and impaired cerebral autoregulation over the entire monitoring period were calculated for each patient. Two hundred and sixty-two patients with a median age of 36 years entered the analysis. The median admission Glasgow Coma Scale was 6, the median Glasgow Outcome Scale was 3, and the mortality at 6 months was 23%. Baroreflex sensitivity (adjusted odds ratio, 0.9; p = 0.02) and relative power of a high frequency band of heart rate variability (adjusted odds ratio, 1.05; p < 0.001) were individually associated with mortality, independently of age, admission Glasgow Coma Scale, intracranial pressure, pressure reactivity index, or cerebral perfusion pressure. Baroreflex sensitivity showed no correlation with intracranial pressure or cerebral perfusion pressure; the correlation with pressure reactivity index was strong in older patients (age, > 60 yr). The relative power of high frequency correlated significantly with intracranial pressure and cerebral perfusion pressure, but not with pressure reactivity index. The relative power of low frequency correlated significantly with pressure reactivity index. Autonomic impairment, as measured by heart rate variability and baroreflex sensitivity, is significantly associated with increased mortality after traumatic brain injury. These effects, though partially interlinked, seem to be independent of age, trauma severity, intracranial pressure, or autoregulatory status, and thus represent a discrete phenomenon in the pathophysiology of traumatic brain injury. Continuous measurements of heart rate variability and baroreflex sensitivity in the neuromonitoring setting of severe traumatic brain injury may carry novel pathophysiological and predictive information.

Reduced-Pressure Chemical Vapor Deposition Growth of Isolated Ge Crystals and Suspended Layers on Micrometric Si Pillars.

PubMed

Skibitzki, Oliver; Capellini, Giovanni; Yamamoto, Yuji; Zaumseil, Peter; Schubert, Markus Andreas; Schroeder, Thomas; Ballabio, Andrea; Bergamaschini, Roberto; Salvalaglio, Marco; Miglio, Leo; Montalenti, Francesco

2016-10-05

In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the peculiar low-energy plasma-enhanced chemical vapor deposition reactor, to widely available epitaxial tools. The growth process was thoroughly analyzed, from the formation of small initial seeds to the final coalescence into a continuous suspended layer, by means of scanning and transmission electron microscopy, X-ray diffraction, and μ-Raman spectroscopy. The preoxidation of the Si pillar sidewalls and the addition of hydrochloric gas in the reactants proved to be key to achieve highly selective Ge growth on the pillars top only, which, in turn, is needed to promote the formation of a continuous Ge layer. Thanks to continuum growth models, we were able to single out the different roles played by thermodynamics and kinetics in the deposition dynamics. We believe that our findings will open the way to the low-cost realization of tens of micrometers thick heteroepitaxial layer (e.g., Ge, SiC, and GaAs) on Si having high crystal quality.

Crude Oil Remote Sensing, Characterization and Cleaning with ContinuousWave and Pulsed Lasers

DTIC Science & Technology

2015-01-23

explained by strong pressure spikes during cavitation in liquid jets . These experiments were not directly tested for the pipe cleaning, but their results...analytical functions (like circular, elliptical and similar shapes). In our case of cylindrical symmetry of the oil film shape is defined by two...the high-pressure (50 – 100 atm) oil and water jets (with cavitations in narrow tubes) revealed a new potential for a more efficient cleaning of

A case of sleep apnea syndrome manifesting severe hypertension with high plasma norepinephrine levels.

PubMed

Makino, Shinya; Iwata, Masanobu; Fujiwara, Masayoshi; Ike, Shinpei; Tateyama, Hitone

2006-06-01

A 55-year-old female was admitted to our hospital with severe hypertension (274/140 mmHg). Endocrinological examination revealed that her plasma levels of norepinephrine (NE) was elevated with high levels of urinary NE, normetanephrine and vanillylmandelic acid (VMA), suggesting the presence of pheochromocytoma. However, neither computed tomography nor MIBG scintigraphy detected any catecholamine-producing tumor in or outside the adrenal glands. She was screened with full polysomnography because of heavy snoring, and the diagnosis of severe obstructive sleep apnea syndrome (OSAS) was made. She was treated with calcium channel blocker for three weeks, but severe hypertension persisted. After treatment with nasal continuous positive airway pressure (CPAP) was added, her blood pressure gradually lowered week by week. Concomitantly, the levels of plasma and urinary NE, urinary normetanephrine and urinary VMA were normalized following nasal CPAP therapy for 2 weeks. Additional treatments with alpha-adrenergic blocker further decreased her home blood pressure. After a year, she continued nasal CPAP therapy and her blood pressure was nearly below 160/100 mmHg. Urinary NE level was slightly above normal range and other catecholamines stayed within the normal range. This case shows that patients with OSAS could develop severe hypertension through elevated sympathetic tone, mimicking pheochromocytoma. Nasal CPAP therapy is recommended not only to improve hypertension and catecholamine excess but also to distinguish the condition from pheochromocytoma.

Process design and optimization of novel wheat-based continuous bioethanol production system.

PubMed

Arifeen, Najmul; Wang, Ruohang; Kookos, Ioannis K; Webb, Colin; Koutinas, Apostolis A

2007-01-01

A novel design of a wheat-based biorefinery for bioethanol production, including wheat milling, gluten extraction as byproduct, fungal submerged fermentation for enzyme production, starch hydrolysis, fungal biomass autolysis for nutrient regeneration, yeast fermentation with recycling integrated with a pervaporation membrane for ethanol concentration, and fuel-grade ethanol purification by pressure swing distillation (PSD), was optimized in continuous mode using the equation-based software General Algebraic Modelling System (GAMS). The novel wheat biorefining strategy could result in a production cost within the range of dollars 0.96-0.50 gal(-1) ethanol (dollars 0.25-0.13 L(-1) ethanol) when the production capacity of the plant is within the range of 10-33.5 million gal y(-1) (37.85-126.8 million L y(-1)). The production of value-added byproducts (e.g., bran-rich pearlings, gluten, pure yeast cells) was identified as a crucial factor for improving the economics of fuel ethanol production from wheat. Integration of yeast fermentation with pervaporation membrane could result in the concentration of ethanol in the fermentation outlet stream (up to 40 mol %). The application of a PSD system that consisted of a low-pressure and a high-pressure column and employing heat integration between the high- and low-pressure columns resulted in reduced operating cost (up to 44%) for fuel-grade ethanol production.

The predictive value of external continuous lumbar drainage, with cerebrospinal fluid outflow controlled by medium pressure valve, in normal pressure hydrocephalus.

PubMed

Panagiotopoulos, V; Konstantinou, D; Kalogeropoulos, A; Maraziotis, T

2005-09-01

Although sporadic studies have described temporary external cerebrospinal fluid (CSF) lumbar drainage as a highly accurate test for predicting the outcome after ventricular shunting in normal pressure hydrocephalus (NPH) patients, a more recent study reports that the positive predictive value of external lumbar drainage (ELD) is high but the negative predictive value is deceptively low. Therefore, we conducted a prospective study in order to evaluate the predictive value of a continuous ELD, with CSF outflow controlled by medium pressure valve, in NPH patients. Twenty-seven patients with presumed NPH were admitted to our department and CSF drainage was carried out by a temporary (ELD) with CSF outflow controlled by a medium pressure valve for five days. All patients received a ventriculoperitoneal shunt using a medium pressure valve based upon preoperative clinical and radiographic criteria of NPH, regardless of ELD outcome. Clinical evaluation of gait disturbances, urinary incontinence and mental status, and radiological evaluation with brain CT was performed prior to and after ELD test, as well as three months after shunting. Twenty-two patients were finally shunted and included in this study. In a three-month follow-up, using a previously validated score system, overall improvement after permanent shunting correlated well to improvement after ELD test (Spearman's rho = 0.462, p = 0.03). When considering any degree of improvement as a positive response, ELD test yielded high positive predictive values for all individual parameters (gait disturbances 94%, 95% CI 71%-100%, urinary incontinence 100%, 95% CI 66%-100%, and mental status 100%, 95% CI 66%-100%) but negative predictive values were low (< 50%) except for cognitive impairment (85%, 95% CI 55%-98%). This study suggests that a positive ELD-valve system test should be considered a reliable criterion for preoperative selection of shunt-responsive NPH patients. In case of a negative ELD-valve system test, further investigation of the presumed NPH patients with additional tests should be performed.

High-calorific biogas production from anaerobic digestion of food waste using a two-phase pressurized biofilm (TPPB) system.

PubMed

Li, Yeqing; Liu, Hong; Yan, Fang; Su, Dongfang; Wang, Yafei; Zhou, Hongjun

2017-01-01

To obtain high calorific biogas via anaerobic digestion without additional upgrading equipment, a two-phase pressurized biofilm system was built up, including a conventional continuously stirred tank reactor and a pressurized biofilm anaerobic reactor (PBAR). Four different pressure levels (0.3, 0.6, 1.0 and 1.7MPa) were applied to the PBAR in sequence, with the organic loading rate maintained at 3.1g-COD/L/d. Biogas production, gas composition, process stability parameters were measured. Results showed that with the pressure increasing from 0.3MPa to 1.7MPa, the pH value decreased from 7.22±0.19 to 6.98±0.05, the COD removal decreased from 93.0±0.9% to 79.7±1.2% and the methane content increased from 80.5±1.5% to 90.8±0.8%. Biogas with higher calorific value of 36.2MJ/m 3 was obtained at a pressure of 1.7MPa. Pressure showed a significant effect on biogas production and gas quality in methanogenesis reactor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nanoscale heterogeneity as remnant hexagonal-type local structures in shocked Cu-Pb and Zr

NASA Astrophysics Data System (ADS)

Tayal, Akhil; Conradson, Steven D.; Batuk, Olga N.; Fensin, Saryu; Cerreta, Ellen; Gray, George T.; Saxena, Avadh

2017-09-01

Extended X-ray absorption fine structure spectroscopy was used to determine the local structure in: (1) Zr that had undergone quasistatic elongation; (2) Zr that had undergone plastic deformation by shock at pressures above and below the ω-phase transformation; and (3) shocked Cu that contained a few percent of insoluble Pb. Below the transition pressure, Zr samples showed only general disorder as increases in the widths of the Zr-Zr pair distributions. Above this pressure, Zr that was a mixture of the original hcp and the high pressure ω-phase when measured by diffraction showed two sets of peaks in its distribution corresponding to these two phases. Some of the ones from the ω-phase were at distances substantially different from those calculated from the diffraction pattern, although they are still consistent with small domains exhibiting stacking faults associated with hexagonal-type structural components exhibiting variability in the [0001] basal plane spacing. A similar result, new pairs at just over 3 and 4 Å consistent with hexagonal-type stacking faults in addition to the original fcc structure, is found in shocked Cu despite the absence of a second diffraction pattern and peak pressures being far below those expected to induce an fcc to hcp transition. This result, therefore, demonstrates that the correlation between high strain rates and reduced stacking fault energy continues down to the length scale of atom pairs. These findings are significant as: (1) a microscopic description of the behavior of systems far from equilibrium; (2) a demonstration of the importance of strain rate at short length scales; and (3) a bridge between the abruptness of macroscopic pressure-induced phase transitions and the continuity of martensitic ones over their fluctuation region in terms of the inverse relationship between the length scale of the martensitic texture, manifested here as ordered lattice distortions and the lower pressure at which such texture first appears relative to the bulk transition pressure.

Role of pressure in angiotensin II-induced renal injury: chronic servo-control of renal perfusion pressure in rats.

PubMed

Mori, Takefumi; Cowley, Allen W

2004-04-01

Renal perfusion pressure was servo-controlled chronically in rats to quantify the relative contribution of elevated arterial pressure versus angiotensin II (Ang II) on the induction of renal injury in Ang II-induced hypertension. Sprague-Dawley rats fed a 4% salt diet were administered Ang II for 14 days (25 ng/kg per minute IV; saline only for sham rats), and the renal perfusion pressure to the left kidney was continuously servo-controlled to maintain a normal pressure in that kidney throughout the period of hypertension. An aortic occluder was implanted around the aorta between the two renal arteries and carotid and femoral arterial pressure were measured continuously throughout the experiment to determine uncontrolled and controlled renal perfusion pressure, respectively. Renal perfusion pressure of uncontrolled, controlled, and sham kidneys over the period of Ang II or saline infusion averaged 152.6+/-7.0, 117.4+/-3.5, and 110.7+/-2.2 mm Hg, respectively. The high-pressure uncontrolled kidneys exhibited tubular necrosis and interstitial fibrosis, especially prominent in the outer medullary region. Regional glomerular sclerosis and interlobular artery injury were also pronounced. Controlled kidneys were significantly protected from interlobular artery injury, juxtamedullary glomeruli injury, tubular necrosis, and interstitial fibrosis as determined by comparing the level of injury. Glomerular injury was not prevented in the outer cortex. Transforming growth factor (TGF)-beta and active NF-kappaB proteins determined by immunohistochemistry were colocalized in the uncontrolled kidney in regions of interstitial fibrosis. We conclude that the preferential juxtamedullary injury found in Ang II hypertension is largely induced by pressure and is probably mediated through the TGF-beta and NF-kappaB pathway.

Synoptic-scale fire weather conditions in Alaska

NASA Astrophysics Data System (ADS)

Hayasaka, Hiroshi; Tanaka, Hiroshi L.; Bieniek, Peter A.

2016-09-01

Recent concurrent widespread fires in Alaska are evaluated to assess their associated synoptic-scale weather conditions. Several periods of high fire activity from 2003 to 2015 were identified using Moderate Resolution Imaging Spectroradiometer (MODIS) hotspot data by considering the number of daily hotspots and their continuity. Fire weather conditions during the top six periods of high fire activity in the fire years of 2004, 2005, 2009, and 2015 were analyzed using upper level (500 hPa) and near surface level (1000 hPa) atmospheric reanalysis data. The top four fire-periods occurred under similar unique high-pressure fire weather conditions related to Rossby wave breaking (RWB). Following the ignition of wildfires, fire weather conditions related to RWB events typically result in two hotspot peaks occurring before and after high-pressure systems move from south to north across Alaska. A ridge in the Gulf of Alaska resulted in southwesterly wind during the first hotspot peak. After the high-pressure system moved north under RWB conditions, the Beaufort Sea High developed and resulted in relatively strong easterly wind in Interior Alaska and a second (largest) hotspot peak during each fire period. Low-pressure-related fire weather conditions occurring under cyclogenesis in the Arctic also resulted in high fire activity under southwesterly wind with a single large hot-spot peak.

A microarray MEMS device for biolistic delivery of vaccine and drug powders.

PubMed

Pirmoradi, Fatemeh Nazly; Pattekar, Ashish V; Linn, Felicia; Recht, Michael I; Volkel, Armin R; Wang, Qian; Anderson, Greg B; Veiseh, Mandana; Kjono, Sandra; Peeters, Eric; Uhland, Scott A; Chow, Eugene M

2015-01-01

We report a biolistic technology platform for physical delivery of particle formulations of drugs or vaccines using parallel arrays of microchannels, which generate highly collimated jets of particles with high spatial resolution. Our approach allows for effective delivery of therapeutics sequentially or concurrently (in mixture) at a specified target location or treatment area. We show this new platform enables the delivery of a broad range of particles with various densities and sizes into both in vitro and ex vivo skin models. Penetration depths of ∼1 mm have been achieved following a single ejection of 200 µg high-density gold particles, as well as 13.6 µg low-density polystyrene-based particles into gelatin-based skin simulants at 70 psi inlet gas pressure. Ejection of multiple shots at one treatment site enabled deeper penetration of ∼3 mm in vitro, and delivery of a higher dose of 1 mg gold particles at similar inlet gas pressure. We demonstrate that particle penetration depths can be optimized in vitro by adjusting the inlet pressure of the carrier gas, and dosing is controlled by drug reservoirs that hold precise quantities of the payload, which can be ejected continuously or in pulses. Future investigations include comparison between continuous versus pulsatile payload deliveries. We have successfully delivered plasmid DNA (pDNA)-coated gold particles (1.15 µm diameter) into ex vivo murine and porcine skin at low inlet pressures of ∼30 psi. Integrity analysis of these pDNA-coated gold particles confirmed the preservation of full-length pDNA after each particle preparation and jetting procedures. This technology platform provides distinct capabilities to effectively deliver a broad range of particle formulations into skin with specially designed high-speed microarray ejector nozzles.

A microarray MEMS device for biolistic delivery of vaccine and drug powders

PubMed Central

Pirmoradi, Fatemeh Nazly; Pattekar, Ashish V; Linn, Felicia; Recht, Michael I; Volkel, Armin R; Wang, Qian; Anderson, Greg B; Veiseh, Mandana; Kjono, Sandra; Peeters, Eric; Uhland, Scott A; Chow, Eugene M

2015-01-01

We report a biolistic technology platform for physical delivery of particle formulations of drugs or vaccines using parallel arrays of microchannels, which generate highly collimated jets of particles with high spatial resolution. Our approach allows for effective delivery of therapeutics sequentially or concurrently (in mixture) at a specified target location or treatment area. We show this new platform enables the delivery of a broad range of particles with various densities and sizes into both in vitro and ex vivo skin models. Penetration depths of ∼1 mm have been achieved following a single ejection of 200 µg high-density gold particles, as well as 13.6 µg low-density polystyrene-based particles into gelatin-based skin simulants at 70 psi inlet gas pressure. Ejection of multiple shots at one treatment site enabled deeper penetration of ∼3 mm in vitro, and delivery of a higher dose of 1 mg gold particles at similar inlet gas pressure. We demonstrate that particle penetration depths can be optimized in vitro by adjusting the inlet pressure of the carrier gas, and dosing is controlled by drug reservoirs that hold precise quantities of the payload, which can be ejected continuously or in pulses. Future investigations include comparison between continuous versus pulsatile payload deliveries. We have successfully delivered plasmid DNA (pDNA)-coated gold particles (1.15 µm diameter) into ex vivo murine and porcine skin at low inlet pressures of ∼30 psi. Integrity analysis of these pDNA-coated gold particles confirmed the preservation of full-length pDNA after each particle preparation and jetting procedures. This technology platform provides distinct capabilities to effectively deliver a broad range of particle formulations into skin with specially designed high-speed microarray ejector nozzles. PMID:26090875

The estimated sensitivity and specificity of compartment pressure monitoring for acute compartment syndrome.

PubMed

McQueen, Margaret M; Duckworth, Andrew D; Aitken, Stuart A; Court-Brown, Charles M

2013-04-17

The aim of our study was to document the estimated sensitivity and specificity of continuous intracompartmental pressure monitoring for the diagnosis of acute compartment syndrome. From our prospective trauma database, we identified all patients who had sustained a tibial diaphyseal fracture over a ten-year period. A retrospective analysis of 1184 patients was performed to record and analyze the documented use of continuous intracompartmental pressure monitoring and the use of fasciotomy. A diagnosis of acute compartment syndrome was made if there was escape of muscles at fasciotomy and/or color change in the muscles or muscle necrosis intraoperatively. A diagnosis of acute compartment syndrome was considered incorrect if it was possible to close the fasciotomy wounds primarily at forty-eight hours. The absence of acute compartment syndrome was confirmed by the absence of neurological abnormality or contracture at the time of the latest follow-up. Of 979 monitored patients identified, 850 fit the inclusion criteria with a mean age of thirty-eight years (range, twelve to ninety-four years), and 598 (70.4%) were male (p < 0.001). A total of 152 patients (17.9%) underwent fasciotomy for the treatment of acute compartment syndrome: 141 had acute compartment syndrome (true positives), six did not have it (false positives), and five underwent fasciotomy despite having a normal differential pressure reading, with subsequent operative findings consistent with acute compartment syndrome (false negatives). Of the 698 patients (82.1%) who did not undergo fasciotomy, 689 had no evidence of any late sequelae of acute compartment syndrome (true negatives) at a mean follow-up time of fifty-nine weeks. The estimated sensitivity of intracompartmental pressure monitoring for suspected acute compartment syndrome was 94%, with an estimated specificity of 98%, an estimated positive predictive value of 93%, and an estimated negative predictive value of 99%. The estimated sensitivity and specificity of continuous intracompartmental pressure monitoring for the diagnosis of acute compartment syndrome following tibial diaphyseal fracture are high; continuous intracompartmental pressure monitoring should be considered for patients at risk for acute compartment syndrome.

WE-G-BRF-09: Force- and Image-Adaptive Strategies for Robotised Placement of 4D Ultrasound Probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhlemann, I; Graduate School for Computing in Life Science, University of Luebeck, Luebeck; Bruder, R

2014-06-15

Purpose: To allow continuous acquisition of high quality 4D ultrasound images for non-invasive live tracking of tumours for IGRT, image- and force-adaptive strategies for robotised placement of 4D ultrasound probes are developed and evaluated. Methods: The developed robotised ultrasound system is based on a 6-axes industrial robot (adept Viper s850) carrying a 4D ultrasound transducer with a mounted force-torque sensor. The force-adaptive placement strategies include probe position control using artificial potential fields and contact pressure regulation by a PD controller strategy. The basis for live target tracking is a continuous minimum contact pressure to ensure good image quality and highmore » patient comfort. This contact pressure can be significantly disturbed by respiratory movements and has to be compensated. All measurements were performed on human subjects under realistic conditions. When performing cardiac ultrasound, rib- and lung shadows are a common source of interference and can disrupt the tracking. To ensure continuous tracking, these artefacts had to be detected to automatically realign the probe. The detection is realised by multiple algorithms based on entropy calculations as well as a determination of the image quality. Results: Through active contact pressure regulation it was possible to reduce the variance of the contact pressure by 89.79% despite respiratory motion of the chest. The results regarding the image processing clearly demonstrate the feasibility to detect image artefacts like rib shadows in real-time. Conclusion: In all cases, it was possible to stabilise the image quality by active contact pressure control and automatically detected image artefacts. This fact enables the possibility to compensate for such interferences by realigning the probe and thus continuously optimising the ultrasound images. This is a huge step towards fully automated transducer positioning and opens the possibility for stable target tracking in ultrasoundguided radiation therapy requiring contact pressure of 5–10 N. This work was supported by the Graduate School for Computing in Medicine and Life Sciences funded by Germany's Excellence Initiative [DFG GSC 235/1].« less

Left ventricular, systemic arterial, and baroreflex responses to ketamine and TEE in chronically instrumented monkeys

NASA Technical Reports Server (NTRS)

Koenig, S. C.; Ludwig, D. A.; Reister, C.; Fanton, J. W.; Ewert, D.; Convertino, V. A.

2001-01-01

Effects of prescribed doses of ketamine five minutes after application and influences of transesophageal echocardiography (TEE) on left ventricular, systemic arterial, and baroreflex responses were investigated to test the hypothesis that ketamine and/or TEE probe insertion alter cardiovascular function. Seven rhesus monkeys were tested under each of four randomly selected experimental conditions: (1) intravenous bolus dose of ketamine (0.5 ml), (2) continuous infusion of ketamine (500 mg/kg/min), (3) continuous infusion of ketamine (500 mg/kg/min) with TEE, and (4) control (no ketamine or TEE). Monkeys were chronically instrumented with a high fidelity, dual-sensor micromanometer to measure left ventricular and aortic pressure and a transit-time ultrasound probe to measure aortic flow. These measures were used to calculate left ventricular function. A 4-element Windkessel lumped-parameter model was used to estimate total peripheral resistance and systemic arterial compliance. Baroreflex response was calculated as the change in R-R interval divided by the change in mean aortic pressure measured during administration of graded concentrations of nitroprusside. The results indicated that five minutes after ketamine application heart rate and left ventricular diastolic compliance decreased while TEE increased aortic systolic and diastolic pressure. We conclude that ketamine may be administered as either a bolus or continuous infusion without affecting cardiovascular function 5 minutes after application while the insertion of a TEE probe will increase aortic pressure. The results for both ketamine and TEE illustrate the classic "Hawthorne Effect," where the observed values are partly a function of the measurement process. Measures of aortic pressure, heart rate, and left ventricular diastolic pressure should be viewed as relative, as opposed to absolute, when organisms are sedated with ketamine or instrumented with a TEE probe.

Applying short-duration pulses as a mean to enhance volatile organic compounds removal by air sparging.

PubMed

Ben Neriah, Asaf; Paster, Amir

2017-10-01

Application of short-duration pulses of high air pressure, to an air sparging system for groundwater remediation, was tested in a two-dimensional laboratory setup. It was hypothesized that this injection mode, termed boxcar, can enhance the remediation efficiency due to the larger ZOI and enhanced mixing which results from the pressure pulses. To test this hypothesis, flow and transport experiments were performed. Results confirm that cyclically applying short-duration pressure pulses may enhance contaminant cleanup. Comparing the boxcar to conventional continuous air-injection shows up to a three-fold increase in the single well radius of influence, dependent on the intensity of the short-duration pressure-pulses. The cleanup efficiency of Toluene from the water was 95% higher than that achieved under continuous injection with the same average conditions. This improvement was attributed to the larger zone of influence and higher average air permeability achieved in the boxcar mode, relative to continuous sparging. Mixing enhancement resultant from recurring pressure pulses was suggested as one of the mechanisms which enhance the contaminant cleanup. The application of a boxcar mode in an existing, multiwell, air sparging setup can be relatively straightforward: it requires the installation of an on-off valve in each of the injection-wells and a central control system. Then, turning off some of the wells, for a short-duration, result in a stepwise increase in injection pressure in the rest of the wells. It is hoped that this work will stimulate the additional required research and ultimately a field scale application of this new injection mode. Copyright © 2017 Elsevier B.V. All rights reserved.

Is increased positive end-expiratory pressure the culprit? Autoresuscitation in a 44-year-old man after prolonged cardiopulmonary resuscitation: a case report.

PubMed

Hagmann, Henning; Oelmann, Katrin; Stangl, Robert; Michels, Guido

2016-12-20

The phenomenon of autoresuscitation is rare, yet it is known to most emergency physicians. However, the pathophysiology of the delayed return of spontaneous circulation remains enigmatic. Among other causes hyperinflation of the lungs and excessively high positive end-expiratory pressure have been suggested, but reports including cardiopulmonary monitoring during cardiopulmonary resuscitation are scarce to support this hypothesis. We report a case of autoresuscitation in a 44-year-old white man after 80 minutes of advanced cardiac life support accompanied by continuous capnometry and repeated evaluation by ultrasound and echocardiography. After prolonged cardiopulmonary resuscitation, refractory electromechanical dissociation on electrocardiogram and ventricular akinesis were recorded. In addition, a precipitous drop in end-tidal partial pressure of carbon dioxide was noted and cardiopulmonary resuscitation was discontinued. Five minutes after withdrawal of all supportive measures his breathing resumed and a perfusing rhythm ensued. Understanding the underlying pathophysiology of autoresuscitation is hampered by a lack of reports including extensive cardiopulmonary monitoring during cardiopulmonary resuscitation in a preclinical setting. In this case, continuous capnometry was combined with repetitive ultrasound evaluation, which ruled out most assumed causes of autoresuscitation. Our observation of a rapid decline in end-tidal partial pressure of carbon dioxide supports the hypothesis of increased intrathoracic pressure. Continuous capnometry can be performed easily during cardiopulmonary resuscitation, also in a preclinical setting. Knowledge of the pathophysiologic mechanisms may lead to facile interventions to be incorporated into cardiopulmonary resuscitation algorithms. A drop in end-tidal partial pressure of carbon dioxide, for example, might prompt disconnection of the ventilation to allow left ventricular filling. Further reports and research on this topic are encouraged.

Meteorologic factors and subjective sleep continuity: a preliminary evaluation

NASA Astrophysics Data System (ADS)

Pandey, Juhi; Grandner, Michael; Crittenden, Crista; Smith, Michael T.; Perlis, Michael L.

2005-01-01

Little research has been undertaken to evaluate whether environmental factors other than bright light influence the individual’s ability to initiate and maintain sleep. In the present analyses, nine meteorologic variables were evaluated for their possible relationship to self-reported sleep continuity in a sample of 43 subjects over a period of 105 days. In this preliminary analysis, high barometric pressure, low precipitation, and lower temperatures were significantly correlated with good sleep continuity. Interestingly, ambient light and lunar phase were not found to be strongly associated sleep diary measures.

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure [Emergent ferromagnetism in USb 2 under pressure

DOE PAGES

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.; ...

2016-05-09

The material USb 2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX 2) series. It is antiferromagnetic with a relatively high transition temperature T N = 204K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb 2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX 2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the T N in USb 2 ismore » enhanced, moving towards that of its smaller sibling UAs 2. But, long before reaching a T N as high as UAs 2, the antiferromagnetism of USb 2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. At last with pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.« less

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure [Emergent ferromagnetism in USb 2 under pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.

The material USb 2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX 2) series. It is antiferromagnetic with a relatively high transition temperature T N = 204K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb 2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX 2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the T N in USb 2 ismore » enhanced, moving towards that of its smaller sibling UAs 2. But, long before reaching a T N as high as UAs 2, the antiferromagnetism of USb 2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. At last with pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.« less

Wear compensating seal means for rotary piston coal feeder

DOEpatents

Gencsoy, Hasan T.; Gardner, John F.

1979-01-01

The present invention is directed to a wear compensating seal arrangement for use in a rotary piston feeder utilized for feeding pulverized coal into a gasifier operating at relatively high pressures and elevated temperatures. The rotary piston feeder has a circular casing with a coal loading opening therein diametrically opposed from a coal discharge and contains a rotatable disoidal rotor having a cylinder in which a reciprocatable piston is disposed. The reciprocation of the piston within the cylinder is provided by a stationary conjugate cam whereby pulverized coal from a coal hopper at atmospheric pressure can be introduced into the cylinder and then discharged therefrom into the high pressure gasifier while maintaining minimal losses of producer gas and the expenditure of minimal energy which would detract from the efficiency of the gasification. The seal arrangement of the present invention is disposed between the rotor and the casing about the coal discharge and prevents the high pressure gases from within the gasifier from escaping between these relatively movable parts during operation of the coal feeder. The seal utilizes a primary seal in contact with the rotor and a secondary seal supporting the primary seal. The primary seal is continuously urged towards the rotor by springs and the high pressure producer gas.

Bonding Transition in SiO2 Glass at High Pressures: Applications to SiO2 Liquid in Earth's Interior

NASA Astrophysics Data System (ADS)

Yoo, C.; Lin, J.; Fukui, H.; Prendergast, D.; Okuchi, T.; Cai, Y.; Hiraoka, N.; Trave, A.; Eng, P.; Hu, M. Y.; Chow, P.

2006-12-01

SiO2 and MgSiO3 liquids are two major components in the magma deep inside the Earth. Knowledge of their electronic bonding characters at high pressures is essential to understanding the complex properties of the materials in the melts. The nature of pressure-induced bonding change in amorphous SiO2 has been an intriguing and long-standing problem that remains to be further understood. For example, previous infrared and X-ray diffraction studies suggested that a continuous transformation from the four- to six-fold coordinated silicon occurred in amorphous SiO2 at high pressures, whereas separate optical Raman studies attributed to a pressure-induced shift in the local ring statistics and a breakdown in the intermediate-range order. Here we have studied the oxygen near K-edge spectra of SiO2 glass to 51 GPa obtained using X-ray Raman scattering in a diamond-anvil cell, which directly probes the electronic bonding character of the sample. Our results provide conclusive evidence for a pressure-induced electronic bonding transition in SiO2 glass at high pressures. Although a progressive decrease in the mean Si-O-Si angle in the SiO4 tetrahedra is believed to be responsible for the irreversible densification in SiO2 glass at high pressures, our observed transition is reversible upon decompression. A similar transformation is also expected to occur in silicate glasses and melts, which will most definitely alter their physical, mechanical and transport properties in the magma chamber deep in the Earth's interior. This work was performed under the auspices of the U.S. DOE by UC/LLNL under Contract W-7405-Eng-48.

Cardiopulmonary Laboratory AFSC 904X0

DTIC Science & Technology

1990-10-01

SET UP POSITIVE END EXPIRATORY PRESSURE (PEEP) DEVICES 100 J321 SET UP CONTINUOUS POSITIVE AIRWAY PRESSURE ( CPAP ) DEVICES 100 J298 ASSIST PHYSICIAN IN...PRESSURE VENTILATORS 61 COMPUTERIZED PULMONARY FUNCTION ANALYZERS 61 TREADMILLS 59 HOLTER MONITOR EQUIPMENT 57 CPAP EQUIPMENT 54 PRESSURE REGULATORS 48...SUCTIONING PROCEDURES 95 J321 SET UP CONTINUOUS POSITIVE AIRWAY PRESSURE ( CPAP ) DEVICES 95 J332 SET UP VOLUME VENTILATORS 93 F148 PERFORM ARTERIAL PUNCTURES 93

Cuffless Blood Pressure Estimation Based on Data-Oriented Continuous Health Monitoring System

PubMed Central

Kawanaka, Haruki; Oguri, Koji

2017-01-01

Measuring blood pressure continuously helps monitor health and also prevent lifestyle related diseases to extend the expectancy of healthy life. Blood pressure, which is nowadays used for monitoring patient, is one of the most useful indexes for prevention of lifestyle related diseases such as hypertension. However, continuously monitoring the blood pressure is unrealistic because of discomfort caused by the tightening of a cuff belt. We have earlier researched the data-oriented blood pressure estimation without using a cuff. Remarkably, our blood pressure estimation method only uses a photoplethysmograph sensor. Therefore, the application is flexible for sensor locations and measuring situations. In this paper, we describe the implementation of our estimation method, the launch of a cloud system which can collect and manage blood pressure data measured by a wristwatch-type photoplethysmograph sensor, and the construction of our applications to visualize life-log data including the time-series data of blood pressure. PMID:28523074

Tissue-Informative Mechanism for Wearable Non-invasive Continuous Blood Pressure Monitoring

NASA Astrophysics Data System (ADS)

Woo, Sung Hun; Choi, Yun Young; Kim, Dae Jung; Bien, Franklin; Kim, Jae Joon

2014-10-01

Accurate continuous direct measurement of the blood pressure is currently available thru direct invasive methods via intravascular needles, and is mostly limited to use during surgical procedures or in the intensive care unit (ICU). Non-invasive methods that are mostly based on auscultation or cuff oscillometric principles do provide relatively accurate measurement of blood pressure. However, they mostly involve physical inconveniences such as pressure or stress on the human body. Here, we introduce a new non-invasive mechanism of tissue-informative measurement, where an experimental phenomenon called subcutaneous tissue pressure equilibrium is revealed and related for application in detection of absolute blood pressure. A prototype was experimentally verified to provide an absolute blood pressure measurement by wearing a watch-type measurement module that does not cause any discomfort. This work is supposed to contribute remarkably to the advancement of continuous non-invasive mobile devices for 24-7 daily-life ambulatory blood-pressure monitoring.

First-principles molecular dynamics simulations of anorthite (CaAl2Si2O8) glass at high pressure

NASA Astrophysics Data System (ADS)

Ghosh, Dipta B.; Karki, Bijaya B.

2018-06-01

We report first-principles molecular dynamics study of the equation of state, structural, and elastic properties of CaAl2Si2O8 glass at 300 K as a function of pressure up to 155 GPa. Our results for the ambient pressure glass show that: (1) as with other silicates, Si atoms remain mostly (> 95%) under tetrahedral oxygen surroundings; (2) unlike anorthite crystal, presence of high-coordination (> 4) Al atoms with 30% abundance; (3) and significant presence of both non-bridging (8%) and triply (17%) coordinated oxygen. To achieve the glass configurations at various pressures, we use two different simulation schedules: cold and hot compression. Cold compression refers to sequential compression at 300 K. Compression at 3000 K and subsequent isochoric quenching to 300 K is considered as hot compression. At the initial stages of compression (0-10 GPa), smooth increase in bond distance and coordination occurs in the hot-compressed glass. Whereas in cold compression, Si (also Al to some extent) displays mainly topological changes (without significantly affecting the average bond distance or coordination) in this pressure interval. Further increase in pressure results in gradual increases in mean coordination, with Si-O (Al-O) coordination eventually reaching and remaining 6 (6.5) at the highest compression. Similarly, the ambient pressure Ca-O coordination of 5.9 increases to 9.5 at 155 GPa. The continuous pressure-induced increase in the proportion of oxygen triclusters along with the appearance and increasing abundance of tetrahedral oxygens results in mean O-T (T = Si and Al) coordination of > 3 from a value of 2.1 at ambient pressure. Due to the absence of kinetic barrier, the hot-compressed glasses consistently produce greater densities and higher coordination numbers than the cold compression cases. Decompressed glasses show irreversible compaction along with retention of high-coordination species when decompressed from pressure ≥ 10 GPa. The different density retention amounts (12, 17, and 20% when decompressed from 12, 40, and 155 GPa, respectively) signifies that the degree of irreversibility depends on the peak pressure of decompression. The calculated compressional and shear wave velocities (5 and 3 km/s at 0 GPa) for the cold-compressed case display sluggish pressure response in the 0-10 GPa interval as opposed to smooth increase in the hot-compressed one. Shear velocity saturates rather rapidly with a value of 5 km/s, whereas compressional wave velocity displays continuous increase, reaching/exceeding 12.5 km/s at 155 GPa. These structural details suggest that the pressure response of the cold-compressed glasses is not only inherently different at the 0-10 GPa interval, the density, coordination, and wave velocity data are consistently lower than the hot-compressed glasses. Hot-compressed glasses may, therefore, be the better analog in the study of high-pressure silicate melts.

High-precision GPS autonomous platforms for sea ice dynamics and physical oceanography

NASA Astrophysics Data System (ADS)

Elosegui, P.; Wilkinson, J.; Olsson, M.; Rodwell, S.; James, A.; Hagan, B.; Hwang, B.; Forsberg, R.; Gerdes, R.; Johannessen, J.; Wadhams, P.; Nettles, M.; Padman, L.

2012-12-01

Project "Arctic Ocean sea ice and ocean circulation using satellite methods" (SATICE), is the first high-rate, high-precision, continuous GPS positioning experiment on sea ice in the Arctic Ocean. The SATICE systems collect continuous, dual-frequency carrier-phase GPS data while drifting on sea ice. Additional geophysical measurements also collected include ocean water pressure, ocean surface salinity, atmospheric pressure, snow-depth, air-ice-ocean temperature profiles, photographic imagery, and others, enabling sea ice drift, freeboard, weather, ice mass balance, and sea-level height determination. Relatively large volumes of data from each buoy are streamed over a satellite link to a central computer on the Internet in near real time, where they are processed to estimate the time-varying buoy positions. SATICE system obtains continuous GPS data at sub-minute intervals with a positioning precision of a few centimetres in all three dimensions. Although monitoring of sea ice motions goes back to the early days of satellite observations, these autonomous platforms bring out a level of spatio-temporal detail that has never been seen before, especially in the vertical axis. These high-resolution data allows us to address new polar science questions and challenge our present understanding of both sea ice dynamics and Arctic oceanography. We will describe the technology behind this new autonomous platform, which could also be adapted to other applications that require high resolution positioning information with sustained operations and observations in the polar marine environment, and present results pertaining to sea ice dynamics and physical oceanography.

The effect of pressure on the hydration structure around hydrophobic solute: A molecular dynamics simulation study

NASA Astrophysics Data System (ADS)

Sarma, Rahul; Paul, Sandip

2012-03-01

Molecular dynamics simulations are performed to study the effects of pressure on the hydrophobic interactions between neopentane molecules immersed in water. Simulations are carried out for five different pressure values ranging from 1 atm to 8000 atm. From potential of mean force calculations, we find that with enhancement of pressure, there is decrease in the well depth of contact minimum (CM) and the relative stability of solvent separated minimum over CM increases. Lower clustering of neopentane at high pressure is also observed in association constant and cluster-structure analysis. Selected site-site radial distribution functions suggest efficient packing of water molecules around neopentane molecules at elevated pressure. The orientational profile calculations of water molecules show that the orientation of water molecules in the vicinity of solute molecule is anisotropic and this distribution becomes flatter as we move away from the solute. Increasing pressure slightly changes the water distribution. Our hydrogen bond properties and dynamics calculations reveal pressure-induced formation of more and more number of water molecules with five and four hydrogen bond at the expense of breaking of two and three hydrogen bonded water molecules. We also find lowering of water-water continuous hydrogen bond lifetime on application of pressure. Implication of these results for relative dispersion of hydrophobic molecules at high pressure are discussed.

Dynamism or Disorder at High Pressures?

NASA Astrophysics Data System (ADS)

Angel, R. J.; Bismayer, U.; Marshall, W. G.

2002-12-01

Phase transitions in minerals at elevated temperatures typically involve dynamics as a natural consequence of the increase in thermal energy available to the system. Classic examples include quartz, cristobalite, and carbonates in which the high-temperature, high symmetry phase is dynamically disordered. This disorder has important thermodynamic consequences, including displacement and curvature of phase boundaries (e.g. calcite-aragonite). In other minerals such as clinopyroxenes and anorthite feldspar, the dynamic behaviour is restricted to the neighbourhood of the phase transition. The fundamental question is whether increasing pressure generally suppresses such dynamic behaviour (as in anorthite; Angel, 1988), or not. In the latter case it must be included in thermodynamic models of high-pressure phase equilibria and seismological modelling of the mantle; the potential dynamics and softening in stishovite may provide the critical observational constraint on the presence or otherwise of free silica in the lower mantle. We have continued to use the lead phosphate as a prototype ferroelastic in which to understand dynamic behaviour, simply because its dynamics and transition behaviour is far better characterised than any mineral. Furthermore, the phase transition is at a pressure where experimental difficulties do not dominate the experimental results. Our previous neutron diffraction study (Angel et al., 2001) revealed that some disorder, either dynamic or static, is retained in the high-symmetry, high-pressure phase just above the phase transition. New neutron diffraction data on the pure material now suggests that this disorder slowly decreases with increasing pressure until at twice the transition pressure it is ordered. Further data for doped material provides insights into the nature of this disorder. Angel (1988) Amer. Mineral. 73:1114. Angel et al (2001) J PhysC 13: 5353.

High-pressure metamorphism in the southern New England Orogen: Implications for long-lived accretionary orogenesis in eastern Australia

NASA Astrophysics Data System (ADS)

Phillips, G.; Offler, R.; Rubatto, D.; Phillips, D.

2015-09-01

New geochemical, metamorphic, and isotopic data are presented from high-pressure metamorphic rocks in the southern New England Orogen (eastern Australia). Conventional and optimal thermobarometry are augmented by U-Pb zircon and 40Ar/39Ar phengite dating to define pressure-temperature-time (P-T-t) histories for the rocks. The P-T-t histories are compared with competing geodynamic models for the Tasmanides, which can be summarized as (i) a retreating orogen model, the Tasmanides formed above a continuous, west dipping, and eastward retreating subduction zone, and (ii) a punctuated orogen model, the Tasmanides formed by several arc accretion, subduction flip, and/or transference events. Whereas both scenarios are potentially supported by the new data, an overlap between the timing of metamorphic recrystallization and key stages of Tasmanides evolution favors a relationship between a single, long-lived subduction zone and the formation, exhumation, and exposure of the high-pressure rocks. By comparison with the retreating orogen model, the following links with the P-T-t histories emerge: (i) exhumation and underplating of oceanic eclogite during the Delamerian Orogeny, (ii) recrystallization of underplated and exhuming high-pressure rocks at amphibolite facies conditions coeval with a period of rollback, and (iii) selective recrystallization of high-pressure rocks at blueschist facies conditions, reflecting metamorphism in a cooled subduction zone. The retreating orogen model can also account for the anomalous location of the Cambrian-Ordovician high-pressure rocks in the Devonian-Carboniferous New England Orogen, where sequential rollback cycles detached and translated parts of the leading edge of the overriding plate to the next, younger orogenic cycle.

Characterization of HMA mixtures containing high reclaimed asphalt pavement content with crumb rubber additives.

DOT National Transportation Integrated Search

2013-03-01

As the price of petroleum and material costs escalate and pressures of maintaining the sustainability of our environment, owners must continually find methods to decrease material costs and maximize their benefits. This paper presents the findings of...

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2013 CFR

2013-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Coatings, Films and Related Substances § 172.260 Oxidized polyethylene. Oxidized polyethylene may... by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total...

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2011 CFR

2011-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Coatings, Films and Related Substances § 172.260 Oxidized polyethylene. Oxidized polyethylene may... by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total...

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2012 CFR

2012-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Coatings, Films and Related Substances § 172.260 Oxidized polyethylene. Oxidized polyethylene may... by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total...

Cooling system for continuous metal casting machines

DOEpatents

Draper, Robert; Sumpman, Wayne C.; Baker, Robert J.; Williams, Robert S.

1988-01-01

A continuous metal caster cooling system is provided in which water is supplied in jets from a large number of small nozzles 19 against the inner surface of rim 13 at a temperature and with sufficient pressure that the velocity of the jets is sufficiently high that the mode of heat transfer is substantially by forced convection, the liquid being returned from the cooling chambers 30 through return pipes 25 distributed interstitially among the nozzles.

In situ synthesis of Cu-BTC (HKUST-1) in macro-/mesoporous silica monoliths for continuous flow catalysis.

PubMed

Sachse, Alexander; Ameloot, Rob; Coq, Bernard; Fajula, François; Coasne, Benoît; De Vos, Dirk; Galarneau, Anne

2012-05-16

The metal-organic framework Cu-BTC has been successfully synthesized as nanoparticles inside the mesopores of silica monoliths featuring a homogeneous macropore network enabling the use of Cu-BTC for continuous flow applications in liquid phase with low pressure drop. High productivity was reached with this catalyst for the Friedländer reaction. This journal is © The Royal Society of Chemistry 2012

Cooling system for continuous metal casting machines

DOEpatents

Draper, R.; Sumpman, W.C.; Baker, R.J.; Williams, R.S.

1988-06-07

A continuous metal caster cooling system is provided in which water is supplied in jets from a large number of small nozzles against the inner surface of rim at a temperature and with sufficient pressure that the velocity of the jets is sufficiently high that the mode of heat transfer is substantially by forced convection, the liquid being returned from the cooling chambers through return pipes distributed interstitially among the nozzles. 9 figs.

Effect of propellant deformation on ignition and combustion processes in solid propellant cracks

NASA Technical Reports Server (NTRS)

Kumar, M.; Kuo, K. K.

1980-01-01

A comprehensive theoretical model was formulated to study the development of convective burning in a solid propellant crack which continually deforms due to burning and pressure loading. In the theoretical model, the effect of interrelated structural deformation and combustion processes was taken into account by considering (1) transient, one dimensional mass, momentum, and energy conservation equations in the gas phase; (2) a transient, one dimensional heat conduction equation in the solid phase; and (3) quasi-static deformation of the two dimensional, linear viscoelastic propellant crack caused by pressure loading. Partial closures may generate substantial local pressure peaks along the crack, implying a strong coupling between chamber pressurization, crack combustion, and propellant deformation, especially when the cracks are narrow and the chamber pressurization rates high. The maximum pressure in the crack cavity is generally higher than that in the chamber. The initial flame-spreading process is not affected by propellant deformation.

Porous matrix structures for alkaline electrolyte fuel cells

NASA Technical Reports Server (NTRS)

Vine, R. W.; Narsavage, S. T.

1975-01-01

A number of advancements have been realized by a continuing research program to develop higher chemically stable porous matrix structures with high bubble pressure (crossover resistance) for use as separators in potassium hydroxide electrolyte fuel cells. More uniform, higher-bubble-pressure asbestos matrices were produced by reconstituting Johns-Manville asbestos paper; Fybex potassium titanate which was found compatible with 42% KOH at 250 F for up to 3000 hr; good agreement was found between bubble pressures predicted by an analytical study and those measured with filtered structures; Teflon-bonded Fybex matrices with bubble pressures greater than 30 psi were obtained by filtering a water slurry of the mixture directly onto fuel cell electrodes; and PBI fibers have satisfactory compatibility with 42% KOH at 250 F.

Magnetization and Hall effect under high pressure in NaV 6O 11

NASA Astrophysics Data System (ADS)

Naka, T.; Matsumoto, T.; Kanke, Y.; Murata, K.

1995-02-01

We have investigated the pressure dependences of magnetization and the Hall coefficient in the ferromagnetic vanadium oxide NaV 6O 11 up to 1.2 GPa. Structural transitions (hexagonal-hexagonal-orthorhombic) occur at TH = 245 K and TL = 35 K at ambient pressure. Meanwhile, the susceptibility obeys the Curie-Weiss law X = C/( T - θ) with antiferromagnetic correlation of θ < 0 at T > TH, with ferromagnetic correlation of θ < 0 at T < TH. The spontaneous magnetization appears below Tc = 64.2 K. With increasing pressure, Tc and magnetization M( T < Tc) decrease, while TH increases. The sign of the Hall coefficient changes continuously (negative-positive-negative) at around T ≈ 170 K and 75 K.

Study of the air-water interfacial properties of biodegradable polyesters and their block copolymers with poly(ethylene glycol).

PubMed

Park, Hae-Woong; Choi, Je; Ohn, Kimberly; Lee, Hyunsuk; Kim, Jin Woong; Won, You-Yeon

2012-08-07

It has been reported that the surface pressure-area isotherm of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) at the air-water interface exhibits several interesting features: (1) a plateau at intermediate compression levels, (2) a sharp rise in surface pressure upon further compression, and (3) marked surface pressure-area hysteresis during compression-expansion cycles. To investigate the molecular origin of this behavior, we conducted an extensive set of surface pressure and AFM imaging measurements with PLGA materials having several different molecular weights and also a poly(D,L-lactic acid-ran-glycolic acid-ran-caprolactone) (PLGACL) material in which the caprolactone monomers were incorporated as a plasticizing component. The results suggest that (i) the plateau in the surface pressure-area isotherm of PLGA (or PLGACL) occurs because of the formation (and collapse) of a continuous monolayer of the polymer under continuous compression; (ii) the PLGA monolayer becomes significantly resistant to compression at high compression because under that condition the collapsed domains become large enough to become glassy (such behavior was not observed in the nonglassy PLGACL sample); and (iii) the isotherm hysteresis is due to a coarsening of the collapsed domains that occurs under high-compression conditions. We also investigated the monolayer properties of PEG-PLGA and PEG-PLGACL diblock copolymers. The results demonstrate that the tendency of PLGA (or PLGACL) to spread on water allows the polymer to be used as an anchoring block to form a smooth biodegradable monolayer of block copolymers at the air-water interface. These diblock copolymer monolayers exhibit protein resistance.

Pressurized tundish for controlling a continuous flow of molten metal

DOEpatents

Lewis, Thomas W.; Hamill, Jr., Paul E.; Ozgu, Mustafa R.; Padfield, Ralph C.; Rego, Donovan N.; Brita, Guido P.

1990-01-01

A pressurized tundish for controlling a continous flow of molten metal characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate.

[How much pressure is applied on the eye balls during craniotomy?: Measurement with FlexiForce contact surface force sensor].

PubMed

Okada, Takeshi; Ishikawa, Tatsuya; Nishimura, Hiromi; Suzuki, Akifumi

2012-12-01

Visual loss following craniotomy is a serious postoperative complication in which elevation of ocular pressure during retraction of the skin flap may cause retinal ischemia. We reported that continuous monitoring of extraocular pressure with the FlexiForce sensor may avoid excessive skin flap retraction during craniotomy and thus prevent ocular complications. Between January 2008 and December 2011, we analyzed data from 46 consecutive patients for whom continuous monitoring of extraocular pressure with FlexiForce sensor was performed. This sensor continuously displays the compressive force, allowing surgeons to check values on the monitor at any time. An alarm sounds if 50 gf is exceeded. We analyzed the temporal course of extraocular pressure and the relationship with patient characteristics. No visual complications were encountered in this patient series. Maximum compressive force during craniotomy was 35.8±27.2 gf, with increases typically seen when surgeons used hooks or drills. However, due to the alarm, no prolonged periods of high force were noted in any patient. Effective methods for reducing force were: (1) taking off hooks on the compressive side; (2) changing the direction of hook tension; and (3) placing cushions such as gauze under the side of the skin flap. Maximum compressive force during microsurgery was 21.8±18.4 gf, and correlated with the beginning force of microsurgery. Compressive force was greatly reduced compared to the force reported previously. The etiologies of visual disability are not fully understood, but this sensor may be helpful in reducing extraocular compression.

Production of Ar and Xe metastables in rare gas mixtures in a dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Mikheyev, Pavel A.; Han, Jiande; Clark, Amanda; Sanderson, Carl; Heaven, Michael C.

2017-12-01

Optically pumped all-rare-gas lasers (OPRGL) utilize metastable atoms of the heavier rare gases as lasing species. The required number density of metastables for efficient laser operation is 1012-1013 cm-3 in He buffer gas at pressures in the 400-1000 Torr range. Such metastable densities are easily produced in a nanosecond pulsed discharge, even at pressures larger than atmospheric, but problems appear when one is trying to achieve continuous production. The reason for low production efficiency in many types of continuous discharge at atmospheric pressure is the low value of the E/N parameter (<5-6 Td). In the present work, we have examined the possibility of using a dielectric barrier discharge (DBD) to provide near continuous, high densities of Ar and Xe metastables. Experiments were performed using a 20 kHz DBD in binary Ar and Xe mixtures with He, and in ternary Ar:Xe:He mixtures at pressures up to 1 atmosphere. Concentrations were measured by means of tunable diode laser absorption spectroscopy. Time-averaged [Ar(1s5)] and [Xe(1s5)] number densities on the order of 1012 cm-3 were readily achieved. The temporal behavior of [Xe(1s5)] throughout the DBD cycle was observed. The results demonstrate the feasibility of using DBDs for OPRGL development. Spectral scans over the absorption lines were also used to examine the pressure broadening coefficients for the 912.3 nm Ar line in He and the Xe 904.5 nm line in Ne and He.

A national project to evaluate and reduce high sound pressure levels from music.

PubMed

Ryberg, Johanna Bengtsson

2009-01-01

The highest recommended sound pressure levels for leisure sounds (music) in Sweden are 100 dB LAeq and 115 dB LAFmax for adults, and 97 dB LAeq and 110 dB LAFmax where children under the age of 13 have access. For arrangements intended for children, levels should be consistently less than 90 dB LAeq. In 2005, a national project was carried out with the aim of improving environments with high sound pressure levels from music, such as concert halls, restaurants, and cinemas. The project covered both live and recorded music. Of Sweden's 290 municipalities, 134 took part in the project, and 93 of these carried out sound measurements. Four hundred and seventy one establishments were investigated, 24% of which exceeded the highest recommended sound pressure levels for leisure sounds in Sweden. Of festival and concert events, 42% exceeded the recommended levels. Those who visit music events/establishments thus run a relatively high risk of exposure to harmful sound levels. Continued supervision in this field is therefore crucial.

Highly water pressurized brown rice improves cognitive dysfunction in senescence-accelerated mouse prone 8 and reduces amyloid beta in the brain.

PubMed

Okuda, Michiaki; Fujita, Yuki; Katsube, Takuya; Tabata, Hiromasa; Yoshino, Katsumi; Hashimoto, Michio; Sugimoto, Hachiro

2018-03-27

Alzheimer's disease (AD) is the most common form of dementia and the number of AD patients continues to increase worldwide. Components of the germ layer and bran of Brown rice (BR) help maintain good health and prevent AD. Because the germ layer and bran absorb little water and are very hard and difficult to cook, they are often removed during processing. To solve these problems, in this study, we tried to use a high-pressure (HP) technique. We produced the highly water pressurized brown rice (HPBR) by pressurizing BR at 600 MPa, and then we fed it to an AD mouse model, senescence-accelerated mouse prone 8, to investigate the therapeutic effects of HPBR on cognitive dysfunction by Y-maze spatial memory test. HP treatment increased the water absorbency of BR without nutrient loss. HPBR ameliorated cognitive dysfunction and reduced the levels of amyloid-β, which is a major protein responsible for AD, in the brain. These results suggest that HPBR is effective for preventing AD.

Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

NASA Technical Reports Server (NTRS)

Kuo, Kenneth K.; Lu, Yeu-Cherng; Chiaverini, Martin J.; Harting, George C.; Johnson, David K.; Serin, Nadir

1995-01-01

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Emergent ferromagnetism and T -linear scattering in USb 2 at high pressure

NASA Astrophysics Data System (ADS)

Jeffries, Jason R.; Stillwell, Ryan L.; Weir, Samuel T.; Vohra, Yogesh K.; Butch, Nicholas P.

2016-05-01

The material USb2 is a correlated, moderately heavy-electron compound within the uranium dipnictide (UX2) series. It is antiferromagnetic with a relatively high transition temperature TN=204 K and a large U-U separation. While the uranium atoms in the lighter dipnictides are considered to be localized, those of USb2 exhibit hybridization and itineracy, promoting uncertainty as to the continuity of the magnetic order within the UX2. We have explored the evolution of the magnetic order by employing magnetotransport measurements as a function of pressure and temperature. We find that the TN in USb2 is enhanced, moving towards that of its smaller sibling UAs2. But, long before reaching a TN as high as UAs2, the antiferromagnetism of USb2 is abruptly destroyed in favor of another magnetic ground state. We identify this pressure-induced ground state as being ferromagnetic based on the appearance of a strong anomalous Hall effect in the transverse resistance in magnetic field. With pressure, this emergent ferromagnetic state is suppressed and ultimately destroyed in favor of a non-Fermi-liquid ground state.

Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

NASA Astrophysics Data System (ADS)

Kuo, Kenneth K.; Lu, Yeu-Cherng; Chiaverini, Martin J.; Harting, George C.; Johnson, David K.; Serin, Nadir

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Fast PSP measurements of wall-pressure fluctuation in low-speed flows: improvements using proper orthogonal decomposition

NASA Astrophysics Data System (ADS)

Peng, Di; Wang, Shaofei; Liu, Yingzheng

2016-04-01

Fast pressure-sensitive paint (PSP) is very useful in flow diagnostics due to its fast response and high spatial resolution, but its applications in low-speed flows are usually challenging due to limitations of paint's pressure sensitivity and the capability of high-speed imagers. The poor signal-to-noise ratio in low-speed cases makes it very difficult to extract useful information from the PSP data. In this study, unsteady PSP measurements were made on a flat plate behind a cylinder in a low-speed wind tunnel (flow speed from 10 to 17 m/s). Pressure fluctuations (Δ P) on the plate caused by vortex-plate interaction were recorded continuously by fast PSP (using a high-speed camera) and a microphone array. Power spectrum of pressure fluctuations and phase-averaged Δ P obtained from PSP and microphone were compared, showing good agreement in general. Proper orthogonal decomposition (POD) was used to reduce noise in PSP data and extract the dominant pressure features. The PSP results reconstructed from selected POD modes were then compared to the pressure data obtained simultaneously with microphone sensors. Based on the comparison of both instantaneous Δ P and root-mean-square of Δ P, it was confirmed that POD analysis could effectively remove noise while preserving the instantaneous pressure information with good fidelity, especially for flows with strong periodicity. This technique extends the application range of fast PSP and can be a powerful tool for fundamental fluid mechanics research at low speed.

Single-Molecule Analysis of the Rotation of F1-ATPase under High Hydrostatic Pressure

PubMed Central

Okuno, Daichi; Nishiyama, Masayoshi; Noji, Hiroyuki

2013-01-01

F1-ATPase is the water-soluble part of ATP synthase and is an ATP-driven rotary molecular motor that rotates the rotary shaft against the surrounding stator ring, hydrolyzing ATP. Although the mechanochemical coupling mechanism of F1-ATPase has been well studied, the molecular details of individual reaction steps remain unclear. In this study, we conducted a single-molecule rotation assay of F1 from thermophilic bacteria under various pressures from 0.1 to 140 MPa. Even at 140 MPa, F1 actively rotated with regular 120° steps in a counterclockwise direction, showing high conformational stability and retention of native properties. Rotational torque was also not affected. However, high hydrostatic pressure induced a distinct intervening pause at the ATP-binding angles during continuous rotation. The pause was observed under both ATP-limiting and ATP-saturating conditions, suggesting that F1 has two pressure-sensitive reactions, one of which is evidently ATP binding. The rotation assay using a mutant F1(βE190D) suggested that the other pressure-sensitive reaction occurs at the same angle at which ATP binding occurs. The activation volumes were determined from the pressure dependence of the rate constants to be +100 Å3 and +88 Å3 for ATP binding and the other pressure-sensitive reaction, respectively. These results are discussed in relation to recent single-molecule studies of F1 and pressure-induced protein unfolding. PMID:24094404

Abnormal cardiovascular responses induced by localized high power microwave exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, S.-T; Brown, D.O.; Johnson, C.E.

1992-05-01

A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz and 16 Hz pulsemodulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in themore » neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power but not to the lower average power microwaves. Depression of pulse pressure, an indication of a decrease in stroke volume, and increased or decreased heart rate were noted in presence of whole-body hyperthermia. The cardiac output of those animals exposed to higher average power microwaves was considered to be below normal as hypothesized. Decreased cardiac output and normal mean arterial pressure resulted in an increase in the total peripheral resistance which was contrary to the anticipated thermal response of animals.« less

Mechanistic modeling of destratification in cryogenic storage tanks using ultrasonics.

PubMed

Jagannathan, T K; Mohanan, Srijith; Nagarajan, R

2014-01-01

Stratification is one of the main causes for vaporization of cryogens and increase of tank pressure during cryogenic storage. This leads subsequent problems such as cavitation in cryo-pumps, reduced length of storage time. Hence, it is vital to prevent stratification to improve the cost efficiency of storage systems. If stratified layers exist inside the tank, they have to be removed by suitable methods without venting the vapor. Sonication is one such method capable of keeping fluid layers mixed. In the present work, a mechanistic model for ultrasonic destratification is proposed and validated with destratification experiments done in water. Then, the same model is used to predict the destratification characteristics of cryogenic liquids such as liquid nitrogen (LN₂), liquid hydrogen (LH₂) and liquid ammonia (LNH₃). The destratification parameters are analysed for different frequencies of ultrasound and storage pressures by considering continuous and pulsed modes of ultrasonic operation. From the results, it is determined that use of high frequency ultrasound (low-power/continuous; high-power/pulsing) or low frequency ultrasound (continuous operation with moderate power) can both be effective in removing stratification. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of Low-Pressure Gas-Phase Pyrolytic Reactions by Mass Spectrometric Techniques,

DTIC Science & Technology

1989-01-01

temperatures and pressures known only as a polymeric substance, is similarly obtained in high purity by heating the polymer to its melting point (105-110’ C...filaments for Curie- point pyrolysis’ J.Anal.Appl.Pyrolysis. 5 (1983) 1-7 (with Helge Egsgaard) 4) ’Heterogeneous catalysis in gas phase reactions studied...by Curie- point pyrolysis. Gas phase pyrolysis of methyl dithio- acetat’ J.Anal.Appl.Pyrolysis. 5 (1983) 257-259 (with Helge Egsgaard) 5) ’Continuous

Coordinated Research Program in Pulsed Power Physics.

DTIC Science & Technology

1984-02-27

storage element and the spark gap sectional area at the injected beam) which helps reduce elec- are both contained within the high pressure vessel of a...ns At the present time the continued research is aimed at duration of the first region corresponds closely to the FWHM answering various unresolved...10-ns e-beam has been used to trigger a spark gap pressurized to 3 atm of N2 . The gap voltage is close to self-breakdown voltage (Le., 0.95 Vb

Determining soil hydrologic characteristics on a remote forest watershed by continuous monitoring of soil water pressures, rainfall and runoff.

Treesearch

L.R. Ahuja; S. A. El-Swaify

1979-01-01

Continuous monitoring of soil-water pressures, rainfall and runoff under natural conditions was tested as a technique for determining soil hydrologic characteristics of a remote forest watershed plot. A completely battery-powered (and thus portable) pressure transducer–scanner–recorder system was assembled for monitoring of soil-water pressures in...

Continuous 24-hour measurement of middle ear pressure.

PubMed

Tideholm, B; Jönsson, S; Carlborg, B; Welinder, R; Grenner, J

1996-07-01

A new method was developed for continuous measurement of the middle ear pressure during a 24-h period. The equipment consisted of a piezo-electric pressure device and a digital memory. To allow continuous pressure recordings during normal every-day activities the equipment was made light and portable. The measurement accuracy of the equipment as well as the base-line and temperature stability were tested and found to meet to our requirements satisfactorily. In 4 volunteers with different middle ear conditions, a small perforation was made through the tympanic membrane. A rubber stopper containing a small polyethylene tube was fitted into the external ear canal. Tubal function tests were made to establish the equipment's ability to monitor fast pressure changes. The tests were well in accordance with other methods of direct pressure measurements. The equipment was carried by the volunteers for 24 h to monitor any slow or rapid dynamic pressure changes in the middle ear. Four continuous 24-h measurements are presented. The method was found to be suitable for valid measurements of dynamic pressure changes in the middle ear during normal every-day activities. It may become a useful instrument in the search for a better understanding of the development of chronic middle ear disease.

Estimation of arterial baroreflex sensitivity in relation to carotid artery stiffness.

PubMed

Lipponen, Jukka A; Tarvainen, Mika P; Laitinen, Tomi; Karjalainen, Pasi A; Vanninen, Joonas; Koponen, Timo; Lyyra-Laitinen, Tiina

2012-01-01

Arterial baroreflex has a significant role in regulating blood pressure. It is known that increased stiffness of the carotid sinus affects mecanotransduction of baroreceptors and therefore limits baroreceptors capability to detect changes in blood pressure. By using high resolution ultrasound video signal and continuous measurement of electrocardiogram (ECG) and blood pressure, it is possible to define elastic properties of artery simultaneously with baroreflex sensitivity parameters. In this paper dataset which consist 38 subjects, 11 diabetics and 27 healthy controls was analyzed. Use of diabetic and healthy test subjects gives wide scale of arteries with different elasticity properties, which provide opportunity to validate baroreflex and artery stiffness estimation methods.

Pressurized Shell Molds For Metal-Matrix Composites

NASA Technical Reports Server (NTRS)

Kashalikar, Uday K.; Lusignea, Richard N.; Cornie, James

1993-01-01

Balanced-pressure molds used to make parts in complex shapes from fiber-reinforced metal-matrix composite materials. In single step, molding process makes parts in nearly final shapes; only minor finishing needed. Because molding pressure same on inside and outside, mold does not have to be especially strong and can be made of cheap, nonstructural material like glass or graphite. Fibers do not have to be cut to conform to molds. Method produces parts with high content of continuous fibers. Parts stiff but light in weight, and coefficients of thermal expansion adjusted. Parts resistant to mechanical and thermal fatigue superior to similar parts made by prior fabrication methods.

Real-Time Smart Textile-Based System to Monitor Pressure Offloading of Diabetic Foot Ulcers.

PubMed

Raviglione, Andrea; Reif, Roberto; Macagno, Maurizio; Vigano, Davide; Schram, Justin; Armstrong, David

2017-09-01

The lifetime risk of developing a diabetic foot ulcer (DFU) is at least 25%. A DFU carries a 50% risk for infection and at least 20% of those receive some form of amputation. The most significant parameter that prevents or delays ulcer healing is high plantar pressure. To improve the patient's healing process, the DFU's plantar pressure should remain cumulatively low. Therefore, a tool that continuously measures the DFU loading, and provides real-time feedback can improve the healing outcome. We report the development of a system capable of continuously measuring the pressure, which could have applications to monitor DFU. The system contains a textile pressure sensor attached to a stretchable band, hardware that collects data and transmits them via Bluetooth to a phone, an app that gathers the data and stores them in the cloud, and a web dashboard that displays the data to the clinician. The sensor was characterized in vitro using the system, and the web-dashboard was developed and tested on simulated patient data. We demonstrate the feasibility of developing the system and characterize the pressure response of the device. As a result, we demonstrate a viable method for monitoring DFU off-loading in real time. The presented study demonstrates the feasibility to develop a simple, modular wearable system that opens up new possibilities for diabetic foot ulcer care by providing a way of monitoring the pressure under the ulcer in real time.

A systematic study of atmospheric pressure chemical vapor deposition growth of large-area monolayer graphene.

PubMed

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Chen, Yu; Lin, Yung-Chen; Qu, Yongquan; Bai, Jingwei; Ivanov, Ivan A; Liu, Gang; Huang, Yu; Duan, Xiangfeng

2012-01-28

Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical vapor deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric pressure chemical vapor deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH 4 partial pressure, while the density of domains decreases with increasing growth temperature and is independent of the CH 4 partial pressure. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm 2 V -1 s -1 at room temperature.

Comparison of Efficacy and Tolerance of Automatic Continuous Positive Airway Pressure Devices With the Optimum Continuous Positive Airway Pressure.

PubMed

Tommi, George; Aronow, Wilbert S; Sheehan, John C; McCleay, Matthew T; Meyers, Patrick G

Patients diagnosed with obstructive sleep apnea syndrome were randomly placed on automatic continuous positive airway pressure (ACPAP) for 2 hours followed by manual titration for the rest of the night. One hundred sixty-one patients entered the study, with at least 50 patients titrated with each of 3 ACPAP devices. The optimum continuous positive airway pressure (CPAP) was defined as the lowest pressure with an apnea-hypoxia index of ≤5/hr, which ranged from 4 cm to 18 cm. Success with ACPAP was approximately 60%-80% when the optimum CPAP was 4-6 cm but fell to below 30% if the optimum CPAP was ≥8 cm (P = 0.001). Average ACPAP ranged from 2 to 10 cm below the optimum level if the optimum CPAP was ≥8 cm. Patients who responded to a low CPAP but deteriorated on higher pressures failed to respond to any of the automatic devices. We recommend that CPAP titration be performed manually before initiation of ACPAP in patients with obstructive sleep apnea. The basal pressure for ACPAP should be the optimum pressure obtained by manual titration. Limits on the upper level of ACPAP may be necessary for patients who deteriorate on higher positive pressures.

Why Can't We Have It All? The Conflict between the Principalship and Motherhood

ERIC Educational Resources Information Center

Jordan, Jacqueline S.

2012-01-01

Being a principal in today's high-stakes environment is a highly demanding job. Much has been written about the stress principals now face in responding to the increased demands and pressures associated with the role. Districts nationwide continue go to great lengths to find administrators of the highest caliber capable of meeting these…

Turbine Engine Clearance Control Systems: Current Practices and Future Directions

NASA Astrophysics Data System (ADS)

Lattime, Scott B.; Steinetz, Bruce M.

2002-09-01

Improved blade tip sealing in the high pressure compressor (HPC) and high pressure turbine (HPT) can provide dramatic reductions in specific fuel consumption (SFC), time-on-wing, compressor stall margin, and engine efficiency as well as increased payload and mission range capabilities. Maintenance costs to overhaul large commercial gas turbine engines can easily exceed 1M. Engine removal from service is primarily due to spent exhaust gas temperature (EGT) margin caused mainly by the deterioration of HPT components. Increased blade tip clearance is a major factor in hot section component degradation. As engine designs continue to push the performance envelope with fewer parts and the market drives manufacturers to increase service life, the need for advanced sealing continues to grow. A review of aero gas turbine engine HPT performance degradation and the mechanisms that promote these losses are discussed. Benefits to the HPT due to improved clearance management are identified. Past and present sealing technologies are presented along with specifications for next generation engine clearance control systems.

Turbine Engine Clearance Control Systems: Current Practices and Future Directions

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.

2002-01-01

Improved blade tip sealing in the high pressure compressor (HPC) and high pressure turbine (HPT) can provide dramatic reductions in specific fuel consumption (SFC), time-on-wing, compressor stall margin, and engine efficiency as well as increased payload and mission range capabilities. Maintenance costs to overhaul large commercial gas turbine engines can easily exceed $1M. Engine removal from service is primarily due to spent exhaust gas temperature (EGT) margin caused mainly by the deterioration of HPT components. Increased blade tip clearance is a major factor in hot section component degradation. As engine designs continue to push the performance envelope with fewer parts and the market drives manufacturers to increase service life, the need for advanced sealing continues to grow. A review of aero gas turbine engine HPT performance degradation and the mechanisms that promote these losses are discussed. Benefits to the HPT due to improved clearance management are identified. Past and present sealing technologies are presented along with specifications for next generation engine clearance control systems.

A CO trace gas detection system based on continuous wave DFB-QCL

NASA Astrophysics Data System (ADS)

Dang, Jingmin; Yu, Haiye; Sun, Yujing; Wang, Yiding

2017-05-01

A compact and mobile system was demonstrated for the detection of carbon monoxide (CO) at trace level. This system adopted a high-power, continuous wave (CW), distributed feedback quantum cascade laser (DFB-QCL) operating at ∼22 °C as excitation source. Wavelength modulation spectroscopy (WMS) as well as second harmonic detection was used to isolate complex, overlapping spectral absorption features typical of ambient pressures and to achieve excellent specificity and high detection sensitivity. For the selected P(11) absorption line of CO molecule, located at 2099.083 cm-1, a limit of detection (LoD) of 26 ppb by volume (ppbv) at atmospheric pressure was achieved with a 1 s acquisition time. Allan deviation analysis was performed to investigate the long term performance of the CO detection system, and a measurement precision of 3.4 ppbv was observed with an optimal integration time of approximate 114 s, which verified the reliable and robust operation of the developed system.

Determination of solid-propellant transient regression rates using a microwave Doppler shift technique

NASA Technical Reports Server (NTRS)

Strand, L. D.; Schultz, A. L.; Reedy, G. K.

1972-01-01

A microwave Doppler shift system, with increased resolution over earlier microwave techniques, was developed for the purpose of measuring the regression rates of solid propellants during rapid pressure transients. A continuous microwave beam is transmitted to the base of a burning propellant sample cast in a metal waveguide tube. A portion of the wave is reflected from the regressing propellant-flame zone interface. The phase angle difference between the incident and reflected signals and its time differential are continuously measured using a high resolution microwave network analyzer and related instrumentation. The apparent propellant regression rate is directly proportional to this latter differential measurement. Experiments were conducted to verify the (1) spatial and time resolution of the system, (2) effect of propellant surface irregularities and compressibility on the measurements, and (3) accuracy of the system for quasi-steady-state regression rate measurements. The microwave system was also used in two different transient combustion experiments: in a rapid depressurization bomb, and in the high-frequency acoustic pressure environment of a T-burner.

49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109...

Pore closure in zeolitic imidazolate frameworks under mechanical pressure.

PubMed

Henke, Sebastian; Wharmby, Michael T; Kieslich, Gregor; Hante, Inke; Schneemann, Andreas; Wu, Yue; Daisenberger, Dominik; Cheetham, Anthony K

2018-02-14

We investigate the pressure-dependent mechanical behaviour of the zeolitic imidazolate framework ZIF-4 (M(im) 2 ; M 2+ = Co 2+ or Zn 2+ , im - = imidazolate) with high pressure, synchrotron powder X-ray diffraction and mercury intrusion measurements. A displacive phase transition from a highly compressible open pore ( op ) phase with continuous porosity (space group Pbca , bulk modulus ∼1.4 GPa) to a closed pore ( cp ) phase with inaccessible porosity (space group P 2 1 / c , bulk modulus ∼3.3-4.9 GPa) is triggered by the application of mechanical pressure. Over the course of the transitions, both ZIF-4 materials contract by about 20% in volume. However, the threshold pressure, the reversibility and the immediate repeatability of the phase transition depend on the metal cation. ZIF-4(Zn) undergoes the op-cp phase transition at a hydrostatic mechanical pressure of only 28 MPa, while ZIF-4(Co) requires about 50 MPa to initiate the transition. Interestingly, ZIF-4(Co) fully returns to the op phase after decompression, whereas ZIF-4(Zn) remains in the cp phase after pressure release and requires subsequent heating to switch back to the op phase. These variations in high pressure behaviour can be rationalised on the basis of the different electron configurations of the respective M 2+ ions (3d 10 for Zn 2+ and 3d 7 for Co 2+ ). Our results present the first examples of op-cp phase transitions ( i.e. breathing transitions) of ZIFs driven by mechanical pressure and suggest potential applications of these functional materials as shock absorbers, nanodampers, or in mechanocalorics.

Continuity of states between the cholesteric → line hexatic transition and the condensation transition in DNA solutions

DOE PAGES

Yasar, Selcuk; Podgornik, Rudolf; Valle-Orero, Jessica; ...

2014-11-05

A new method of finely temperature-tuning osmotic pressure allows one to identify the cholesteric → line hexatic transition of oriented or unoriented long-fragment DNA bundles in monovalent salt solutions as first order, with a small but finite volume discontinuity. This transition is similar to the osmotic pressure-induced expanded → condensed DNA transition in polyvalent salt solutions at small enough polyvalent salt concentrations. Therefore there exists a continuity of states between the two. This finding with the corresponding empirical equation of state, effectively relates the phase diagram of DNA solutions for monovalent salts to that for polyvalent salts and sheds somemore » light on the complicated interactions between DNA molecules at high densities.« less

Rapid gas hydrate formation processes: Will they work?

DOE PAGES

Brown, Thomas D.; Taylor, Charles E.; Bernardo, Mark P.

2010-06-07

Researchers at DOE’s National Energy Technology Laboratory (NETL) have been investigating the formation of synthetic gas hydrates, with an emphasis on rapid and continuous hydrate formation techniques. The investigations focused on unconventional methods to reduce dissolution, induction, nucleation and crystallization times associated with natural and synthetic hydrates studies conducted in the laboratory. Numerous experiments were conducted with various high-pressure cells equipped with instrumentation to study rapid and continuous hydrate formation. The cells ranged in size from 100 mL for screening studies to proof-of-concept studies with NETL’s 15-Liter Hydrate Cell. The results from this work demonstrate that the rapid and continuousmore » formation of methane hydrate is possible at predetermined temperatures and pressures within the stability zone of a Methane Hydrate Stability Curve.« less

Obstructive sleep apnea syndrome and hypertension: mechanism of the linkage and 24-h blood pressure control.

PubMed

Kario, Kazuomi

2009-07-01

Hypertensive patients with obstructive sleep apnea syndrome (OSAS) constitute a high-risk group for metabolic syndrome. OSAS directly induces negative intrathoracic pressure and decreases pulmonary stretch receptor stimulation, chemoreceptor stimulation, hypoxemia, hypercapnia and microarousal. These changes potentiate various risk factors, including the sympathetic nervous system, renin-angiotensin-aldosterone system and inflammation. Early detection and treatment of OSAS in asymptomatic hypertensive patients is essentially important to prevent hypertensive target organ damage and subsequent cardiovascular events. Continuous positive airway pressure (CPAP) therapy, a first-line treatment in hypertensive patients with moderate to severe OSAS, reduces ambulatory BP level, particularly during the sleep period, and midnight BP surge. However, individual differences in the BP-lowering effect of CPAP have been observed. OSAS hypertensive patients who do not tolerate CPAP remain at a high risk for cardiovascular disease because of negative intrathoracic pressure and need more aggressive antihypertensive treatment to achieve 24-h BP control with nocturnal BP <120/70 mm Hg.

Overview of LDX Results

NASA Astrophysics Data System (ADS)

Kesner, J.; Boxer, A. C.; Ellsworth, J. L.; Karim, I.; Garnier, D. T.; Hansen, A. K.; Mauel, M. E.; Ortiz, E. E.

2006-10-01

The levitated dipole experiment (LDX) is a new research facility that is investigating plasma confinement and stability in a dipole magnetic field configuration as a possible catalyzed DD fusion power source that would avoid the burning of tritium. We report the production of high beta plasma confined by a laboratory superconducting dipole using neutral gas fueling and electron cyclotron resonance heating (ECRH). The pressure results from a population of anisotropic energetic trapped electrons that is sustained by microwave heating provided sufficient neutral gas is supplied to the plasma. The trapped electron beta was observed to be limited by the hot electron interchange (HEI) instability, but when the neutral gas was programmed so as to maintain the deuterium gas pressure near 0.2 mPa, the fast electron pressure increased by more than a factor of ten and the resulting stable high beta plasma was maintained quasi-continuously for up to 14 seconds. Low frequency (<10 kHz) fluctuations are sometimes observed at low neutral base pressure.

Transient processes in the combustion of nitramine propellants

NASA Technical Reports Server (NTRS)

Cohen, N. S.; Strand, L. D.

1978-01-01

A transient combustion model of nitramine propellants is combined with an isentropic compression shock formation model to determine the role of nitramine propellant combustion in DDT, excluding effects associated with propellant structural properties or mechanical behavior. The model is derived to represent the closed pipe experiment that is widely used to characterize explosives, except that the combustible material is a monolithic charge rather than compressed powder. Computations reveal that the transient combustion process cannot by itself produce DDT by this model. Compressibility of the solid at high pressure is the key factor limiting pressure buildups created by the combustion. On the other hand, combustion mechanisms which promote pressure buildups are identified and related to propellant formulation variables. Additional combustion instability data for nitramine propellants are presented. Although measured combustion response continues to be low, more data are required to distinguish HMX and active binder component contributions. A design for a closed vessel apparatus for experimental studies of high pressure combustion is discussed.

49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW...

40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in...

Process and continuous apparatus for chemical conversion of materials

DOEpatents

Rugg, Barry; Stanton, Robert

1983-01-01

A process and apparatus for the acid hydrolysis of waste cellulose to glucose of the type wherein waste cellulose is continuously fed into an inlet port of a twin screw extruder, water is continuously fed into reaction zone in the extruder, downstream of the inlet port, the cellulose is continuously reacted with water in the presence of an acid catalyst at elevated temperature and pressure in the reaction zone while being continuously conveyed to an outlet port of the extruder having a given diameter and the reacted cellulose is discharged from the extruder while the elevated temperature and pressure in the reaction zone is maintained. The elevated pressure is maintained by forming a dynamic seal zone at the upstream end of the reaction and continuously discharging the reacted material downstream of the outlet port at a predetermined volume rate of flow to maintain the pressure by passing the discharge through an orifice pipe having a smaller diameter than the given diameter of the outlet port.

A High-Value, Low-Cost Bubble Continuous Positive Airway Pressure System for Low-Resource Settings: Technical Assessment and Initial Case Reports

PubMed Central

Brown, Jocelyn; Machen, Heather; Kawaza, Kondwani; Mwanza, Zondiwe; Iniguez, Suzanne; Lang, Hans; Gest, Alfred; Kennedy, Neil; Miros, Robert; Richards-Kortum, Rebecca; Molyneux, Elizabeth; Oden, Maria

2013-01-01

Acute respiratory infections are the leading cause of global child mortality. In the developing world, nasal oxygen therapy is often the only treatment option for babies who are suffering from respiratory distress. Without the added pressure of bubble Continuous Positive Airway Pressure (bCPAP) which helps maintain alveoli open, babies struggle to breathe and can suffer serious complications, and frequently death. A stand-alone bCPAP device can cost $6,000, too expensive for most developing world hospitals. Here, we describe the design and technical evaluation of a new, rugged bCPAP system that can be made in small volume for a cost-of-goods of approximately $350. Moreover, because of its simple design—consumer-grade pumps, medical tubing, and regulators—it requires only the simple replacement of a <$1 diaphragm approximately every 2 years for maintenance. The low-cost bCPAP device delivers pressure and flow equivalent to those of a reference bCPAP system used in the developed world. We describe the initial clinical cases of a child with bronchiolitis and a neonate with respiratory distress who were treated successfully with the new bCPAP device. PMID:23372661

Low-pressure pulsed focused ultrasound with microbubbles promotes an anticancer immunological response.

PubMed

Liu, Hao-Li; Hsieh, Han-Yi; Lu, Li-An; Kang, Chiao-Wen; Wu, Ming-Fang; Lin, Chun-Yen

2012-11-11

High-intensity focused-ultrasound (HIFU) has been successfully employed for thermal ablation of tumors in clinical settings. Continuous- or pulsed-mode HIFU may also induce a host antitumor immune response, mainly through expansion of antigen-presenting cells in response to increased cellular debris and through increased macrophage activation/infiltration. Here we demonstrated that another form of focused ultrasound delivery, using low-pressure, pulsed-mode exposure in the presence of microbubbles (MBs), may also trigger an antitumor immunological response and inhibit tumor growth. A total of 280 tumor-bearing animals were subjected to sonographically-guided FUS. Implanted tumors were exposed to low-pressure FUS (0.6 to 1.4 MPa) with MBs to increase the permeability of tumor microvasculature. Tumor progression was suppressed by both 0.6 and 1.4-MPa MB-enhanced FUS exposures. We observed a transient increase in infiltration of non-T regulatory (non-Treg) tumor infiltrating lymphocytes (TILs) and continual infiltration of CD8+ cytotoxic T-lymphocytes (CTL). The ratio of CD8+/Treg increased significantly and tumor growth was inhibited. Our findings suggest that low-pressure FUS exposure with MBs may constitute a useful tool for triggering an anticancer immune response, for potential cancer immunotherapy.

Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster with Anode Layer

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Markusic, T. E.; Stanojev, B. J.

2007-01-01

Two prototype bismuth propellant feed systems were constructed and operated in conjunction with a propellant vaporizer. One system provided bismuth to a vaporizer using gas pressurization but did not include a means to measure the flow rate. The second system incorporated an electromagnetic pump to provide fine control of the hydrostatic pressure and a new type of in-line flow sensor that was developed for accurate, real-time measurement of the mass flow rate. High-temperature material compatibility was a driving design requirement for the pump and flow sensor, leading to the selection of Macor for the main body of both components. Posttest inspections of both components revealed no degradation of the material. The gas pressurization system demonstrated continuous pressure control over a range from zero to 200 torr. In separate proof-of-concept experiments, the electromagnetic pump produced a linear pressure rise as a function of current that compared favorably with theoretical pump pressure predictions, producing a pressure rise of 10 kPa at 30 A. Preliminary flow sensor operation indicated a bismuth flow rate of 6 mg/s with an uncertainty of plus or minus 6%. An electronics suite containing a real-time controller was successfully used to control the entire system, simultaneously monitoring all power supplies and performing data acquisition duties.

The structure of MgO-SiO2 glasses at elevated pressure.

PubMed

Wilding, Martin; Guthrie, Malcolm; Kohara, Shinji; Bull, Craig L; Akola, Jaakko; Tucker, Matt G

2012-06-06

The magnesium silicate system is an important geophysical analogue and neutron diffraction data from glasses formed in this system may also provide an initial framework for understanding the structure-dependent properties of related liquids that are important during planetary formation. Neutron diffraction data collected in situ for a single composition (38 mol% SiO(2)) magnesium silicate glass sample shows local changes in structure as pressure is increased from ambient conditions to 8.6 GPa at ambient temperature. A method for obtaining the fully corrected, total structure factor, S(Q), has been developed that allows accurate structural characterization as this weakly scattering glass sample is compressed. The measured S(Q) data indicate changes in chemical ordering with pressure and the real-space transforms show an increase in Mg-O coordination number and a distortion of the local environment around magnesium ions. We have used reverse Monte Carlo methods to compare the high pressure and ambient pressure structures and also compare the high pressure form with a more silica-poor glass (Mg(2)SiO(4)) that represents the approach to a more dense, void-free and topologically ordered structure. The Mg-O coordination number increases with pressure and we also find that the degree of continuous connectivity of Si-O bonds increases via a collapse of interstices.

Design of a high-pressure circulating pump for viscous liquids.

PubMed

Seifried, Bernhard; Temelli, Feral

2009-07-01

The design of a reciprocating dual action piston pump capable of circulating viscous fluids at pressures of up to 34 MPa (5000 psi) and temperatures up to 80 degrees C is described. The piston of this pump is driven by a pair of solenoids energized alternatively by a 12 V direct current power supply controlled by an electronic controller facilitating continuously adjustable flow rates. The body of this seal-less pump is constructed using off-the-shelf parts eliminating the need for custom made parts. Both the electronic controller and the pump can be assembled relatively easily. Pump performance has been evaluated at room temperature (22 degrees C) and atmospheric pressure using liquids with low and moderately high viscosities, such as ethanol and corn oil, respectively. At ambient conditions, the pump delivered continuous flow of ethanol and corn oil at a flow rate of up to 170 and 17 cm3/min, respectively. For pumping viscous fluids comparable to corn oil, an optimum reciprocation frequency was ascertained to maximize flow rate. For low viscosity liquids such as ethanol, a linear relationship between the flow rate and reciprocation frequency was determined up to the maximum reciprocation frequency of the pump. Since its fabrication, the pump has been used in our laboratory for circulating triglycerides in contact with supercritical carbon dioxide at pressures of up to 25 MPa (3600 psi) and temperatures up to 70 degrees C on a daily basis for a total of more than 1500 h of operation functioning trouble free.

Continuous Flow Atmospheric Pressure Laser Desorption/Ionization Using a 6–7-µm-Band Mid-Infrared Tunable Laser for Biomolecular Mass Spectrometry

PubMed Central

Hiraguchi, Ryuji; Hazama, Hisanao; Senoo, Kenichirou; Yahata, Yukinori; Masuda, Katsuyoshi; Awazu, Kunio

2014-01-01

A continuous flow atmospheric pressure laser desorption/ionization technique using a porous stainless steel probe and a 6–7-µm-band mid-infrared tunable laser was developed. This ion source is capable of direct ionization from a continuous flow with a high temporal stability. The 6–7-µm wavelength region corresponds to the characteristic absorption bands of various molecular vibration modes, including O–H, C=O, CH3 and C–N bonds. Consequently, many organic compounds and solvents, including water, have characteristic absorption peaks in this region. This ion source requires no additional matrix, and utilizes water or acetonitrile as the solvent matrix at several absorption peak wavelengths (6.05 and 7.27 µm, respectively). The distribution of multiply-charged peptide ions is extremely sensitive to the temperature of the heated capillary, which is the inlet of the mass spectrometer. This ionization technique has potential for the interface of liquid chromatography/mass spectrometry (LC/MS). PMID:24937686

Active Temperature Compensation Using a High-Temperature, Fiber Optic, Hybrid Pressure and Temperature Sensor

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Palmer, Matthew E.; Davis, Matthew A.; Engelbrecht, Gordon P.

2006-01-01

Luna Innovations has developed a novel, fiber optic, hybrid pressure-temperature sensor system for extremely high-temperature environments that is capable of reliable operation up to 1050 °C. This system is based on the extremely high-temperature fiber optic sensors already demonstrated during previous work. The novelty of the sensors presented here lies in the fact that pressure and temperature are measured simultaneously with a single fiber and a single transducer. This hybrid approach will enable highly accurate active temperature compensation and sensor self-diagnostics not possible with other platforms. Hybrid pressure and temperature sensors were calibrated by varying both pressure and temperature. Implementing active temperature compensation resulted in a ten-fold reduction in the temperature-dependence of the pressure measurement. Sensors were tested for operability in a relatively high neutron dose environment up to 6.9×1017 n/cm2. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation. Additional development is needed, however, before these advantages can be realized. This paper will highlight recent demonstrations of fiber optic sensors in environments relevant to space nuclear applications. Successes and lessons learned will be highlighted. Additionally, development needs will be covered which will suggest a framework for a coherent plan to continue work in this area.

Implementing Inclusive Education in Primary Schools in Bangladesh: Recommended Strategies

ERIC Educational Resources Information Center

Ahmmed, Masud; Mullick, Jahirul

2014-01-01

Continued discrimination towards, and exclusion of, children with special needs, combined with the high dropout rate of students from socio-economically disadvantaged backgrounds, creates considerable pressure on the inclusive education (IE) reform initiatives of developing countries. To minimise the challenges to implementing IE reform policies…

21 CFR 177.1620 - Polyethylene, oxidized.

Code of Federal Regulations, 2013 CFR

2013-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic...,200, as determined by high temperature vapor pressure osmometry, contains a maximum of 5 percent by weight of total oxygen, and has an acid value of 9 to 19. (b) The finished food-contact article, when...

21 CFR 177.1620 - Polyethylene, oxidized.

Code of Federal Regulations, 2011 CFR

2011-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic...,200, as determined by high temperature vapor pressure osmometry, contains a maximum of 5 percent by weight of total oxygen, and has an acid value of 9 to 19. (b) The finished food-contact article, when...

21 CFR 177.1620 - Polyethylene, oxidized.

Code of Federal Regulations, 2012 CFR

2012-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic...,200, as determined by high temperature vapor pressure osmometry, contains a maximum of 5 percent by weight of total oxygen, and has an acid value of 9 to 19. (b) The finished food-contact article, when...

21 CFR 177.1620 - Polyethylene, oxidized.

Code of Federal Regulations, 2010 CFR

2010-04-01

... FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic...,200, as determined by high temperature vapor pressure osmometry, contains a maximum of 5 percent by weight of total oxygen, and has an acid value of 9 to 19. (b) The finished food-contact article, when...

A forskolin derivative, colforsin daropate hydrochloride, inhibits the decrease in cortical renal blood flow induced by noradrenaline or angiotensin II in anesthetized rats.

PubMed

Ogata, Junichi; Minami, Kouichiro; Segawa, Kayoko; Uezono, Yasuhito; Shiraishi, Munehiro; Yamamoto, Chikako; Sata, Takeyoshi; Sung-Teh, Kim; Shigematsu, Akio

2004-01-01

A forskolin derivative, colforsin daropate hydrochloride (CDH), acts directly on adenylate cyclase to increase the intracellular cyclic adenosine monophosphate levels which produce a positive inotropic effect and a lower blood pressure. However, little is known about the effects of CDH on the renal function. We used laser Doppler flowmetry to measure the cortical renal blood flow (RBF) in male Wistar rats given a continuous intravenous infusion of CDH and evaluated the effects of CDH on the noradrenaline (NA) and angiotensin II (AngII) induced increases in blood pressure and reductions in RBF. Continuous intravenous administration of CDH at 0.25 microg/kg/min did not affect the mean arterial pressure (MAP), but increased heart rate and RBF. Continuous intravenous administration of CDH at high doses (0.5-0.75 microg/kg/min) decreased the MAP, with little effect on the RBF. The administration of exogenous NA (1.7 microg/kg) increased the MAP and decreased the RBF. However, a bolus injection of NA did not decrease the RBF during continuous intravenous administration of CDH, and CDH did not affect the NA-induced increase in MAP. The administration of exogenous AngII (100 ng/kg) increased MAP and decreased RBF and heart rate, but a bolus injection of AngII did not decrease RBF during continuous intravenous administration of CDH. These results suggest that CDH plays a protective role against the pressor effects and the decrease in RBF induced by NA or AngII. Copyright 2004 S. Karger AG, Basel

Practical development of continuous supercritical fluid process using high pressure and high temperature micromixer

NASA Astrophysics Data System (ADS)

Kawasaki, Shin-Ichiro; Sue, Kiwamu; Ookawara, Ryuto; Wakashima, Yuichiro; Suzuki, Akira

2015-12-01

In the synthesis of metal oxide fine particles by continuous supercritical hydrothermal method, the particle characteristics are greatly affected by not only the reaction conditions (temperature, pressure, residence time, concentration, etc.), but also the heating rate from ambient to reaction temperature. Therefore, the heating method by direct mixing of starting solution at room temperature with supercritical water is a key technology for the particle production having smaller size and narrow distribution. In this paper, mixing engineering study through comparison between conventional T-shaped mixers and recently developed swirl mixers was carried out in the hydrothermal synthesis of NiO nanoparticles from Ni(NO3)2 aqueous solution at 400 °C and 30 MPa. Inner diameter in the mixers and total flow rates were varied. Furthermore, the heating rate was calculated by computational fluid dynamics (CFD) simulation. Relationship between the heating rate and the average particle size were discussed. It was clarified that the miniaturization of mixer inner diameter and the use of the swirl flow were effective for improving mixing performance and contributed to produce small and narrow distribution particle under same experimental condition of flow rate, temperature, pressure, residence time, and concentration of the starting materials. We have focused the mixer optimization due to a difference in fluid viscosity.

Cavitation control on a 2D hydrofoil through a continuous tangential injection of liquid: Experimental study

NASA Astrophysics Data System (ADS)

Timoshevskiy, M. V.; Zapryagaev, I. I.; Pervunin, K. S.; Markovich, D. M.

2016-10-01

In the paper, the possibility of active control of a cavitating flow over a 2D hydrofoil that replicates a scaled-down model of high-pressure hydroturbine guide vane (GV) was tested. The flow manipulation was implemented by a continuous tangential liquid injection at different flow rates through a spanwise slot in the foil surface. In experiments, the hydrofoil was placed in the test channel at the attack angle of 9°. Different cavitation conditions were reached by varying the cavitation number and injection velocity. In order to study time dynamics and spatial patterns of partial cavities, high-speed imaging was employed. A PIV method was used to measure the mean and fluctuating velocity fields over the hydrofoil. Hydroacoustic measurements were carried out by means of a pressure transducer to identify spectral characteristics of the cavitating flow. It was found that the present control technique is able to modify the partial cavity pattern (or even totally suppress cavitation) in case of stable sheet cavitation and change the amplitude of pressure pulsations at unsteady regimes. The injection technique makes it also possible to significantly influence the spatial distributions of the mean velocity and its turbulent fluctuations over the GV section for non-cavitating flow and sheet cavitation.

Application of Pressure Sensitive Paint in Hypersonic Flows

NASA Technical Reports Server (NTRS)

Jules, Kenol; Carbonaro, Mario; Zemsch, Stephan

1995-01-01

It is well known in the aerodynamic field that pressure distribution measurement over the surface of an aircraft model is a problem in experimental aerodynamics. For one thing, a continuous pressure map can not be obtained with the current experimental methods since they are discrete. Therefore, interpolation or CFD methods must be used for a more complete picture of the phenomenon under study. For this study, a new technique was investigated which would provide a continuous pressure distribution over the surface under consideration. The new method is pressure sensitive paint. When pressure sensitive paint is applied to an aerodynamic surface and placed in an operating wind-tunnel under appropriate lighting, the molecules luminesce as a function of the local pressure of oxygen over the surface of interest during aerodynamic flow. The resulting image will be brightest in the areas of low pressure (low oxygen concentration), and less intense in the areas of high pressure (where oxygen is most abundant on the surface). The objective of this investigation was to use pressure sensitive paint samples from McDonnell Douglas (MDD) for calibration purpose in order to assess the response of the paint under appropriate lighting and to use the samples over a flat plate/conical fin mounted at 75 degrees from the center of the plate in order to study the shock/boundary layer interaction at Mach 6 in the Von Karman wind-tunnel. From the result obtained it was concluded that temperature significantly affects the response of the paint and should be given the uppermost attention in the case of hypersonic flows. Also, it was found that past a certain temperature threshold, the paint intensity degradation became irreversible. The comparison between the pressure tap measurement and the pressure sensitive paint showed the right trend. However, there exists a shift when it comes to the actual value. Therefore, further investigation is under way to find the cause of the shift.

Analysis and Design of Cryogenic Pressure Vessels for Automotive Hydrogen Storage

NASA Astrophysics Data System (ADS)

Espinosa-Loza, Francisco Javier

Cryogenic pressure vessels maximize hydrogen storage density by combining the high pressure (350-700 bar) typical of today's composite pressure vessels with the cryogenic temperature (as low as 25 K) typical of low pressure liquid hydrogen vessels. Cryogenic pressure vessels comprise a high-pressure inner vessel made of carbon fiber-coated metal (similar to those used for storage of compressed gas), a vacuum space filled with numerous sheets of highly reflective metalized plastic (for high performance thermal insulation), and a metallic outer jacket. High density of hydrogen storage is key to practical hydrogen-fueled transportation by enabling (1) long-range (500+ km) transportation with high capacity vessels that fit within available spaces in the vehicle, and (2) reduced cost per kilogram of hydrogen stored through reduced need for expensive structural material (carbon fiber composite) necessary to make the vessel. Low temperature of storage also leads to reduced expansion energy (by an order of magnitude or more vs. ambient temperature compressed gas storage), potentially providing important safety advantages. All this is accomplished while simultaneously avoiding fuel venting typical of cryogenic vessels for all practical use scenarios. This dissertation describes the work necessary for developing and demonstrating successive generations of cryogenic pressure vessels demonstrated at Lawrence Livermore National Laboratory. The work included (1) conceptual design, (2) detailed system design (3) structural analysis of cryogenic pressure vessels, (4) thermal analysis of heat transfer through cryogenic supports and vacuum multilayer insulation, and (5) experimental demonstration. Aside from succeeding in demonstrating a hydrogen storage approach that has established all the world records for hydrogen storage on vehicles (longest driving range, maximum hydrogen storage density, and maximum containment of cryogenic hydrogen without venting), the work also demonstrated a methodology for computationally efficient detailed modeling of cryogenic pressure vessels. The work continues with support of the US Department of Energy to demonstrate a new generation of cryogenic vessels anticipated to improve on the hydrogen storage performance figures previously imposed in this project. The author looks forward to further contributing to a future of long-range, inexpensive, and safe zero emissions transportation.

Mechanisms of decreased left ventricular preload during continuous positive pressure ventilation in ARDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhainaut, J.F.; Devaux, J.Y.; Monsallier, J.F.

1986-07-01

Continuous positive pressure ventilation is associated with a reduction in left ventricular preload and cardiac output, but the mechanisms responsible are controversial. The decrease in left ventricular preload may result exclusively from a decreased systemic venous return due to increased pleural pressure, or from an additional effect such as decreased left ventricular compliance. To determine the mechanisms responsible, we studied the changes in cardiac output induced by continuous positive pressure ventilation in eight patients with the adult respiratory distress syndrome. We measured cardiac output by thermodilution, and biventricular ejection fraction by equilibrium gated blood pool scintigraphy. Biventricular end-diastolic volumes weremore » then calculated by dividing stroke volume by ejection fraction. As positive end-expiratory pressure increased from 0 to 20 cm H/sub 2/O, stroke volume and biventricular end-diastolic volumes fell about 25 percent, and biventricular ejection fraction remained unchanged. At 20 cm H/sub 2/O positive end-expiratory pressure, volume expansion for normalizing cardiac output restored biventricular end-diastolic volumes without markedly changing biventricular end-diastolic transmural pressures. The primary cause of the reduction in left ventricular preload with continuous positive pressure ventilation appears to be a fall in venous return and hence in right ventricular stroke volume, without evidence of change in left ventricular diastolic compliance.« less

Aging results for PRD 49 III/epoxy and Kevlar 49/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Hamstad, M. A.

1983-01-01

Kevlar 49/epoxy composite is growing in use as a structural material because of its high strength-to-weight ratio. Currently, it is used for the Trident rocket motor case and for various pressure vessels on the Space Shuttle. In 1979, the initial results for aging of filament-wound cylindrical pressure vessels which were manufactured with preproduction Kevlar 49 (Hamstad, 1979) were published. This preproduction fiber was called PRD 49 III. This report updates the continuing study to 10-year data and also presents 7.5-year data for spherical pressure vessels wound with production Kevlar 49. For completeness, this report will again describe the specimens of the original study with PRD 49 as well as specimens for the new study with Kevlar 49.

Neural control of vascular reactions: impact of emotion and attention.

PubMed

Okon-Singer, Hadas; Mehnert, Jan; Hoyer, Jana; Hellrung, Lydia; Schaare, Herma Lina; Dukart, Juergen; Villringer, Arno

2014-03-19

This study investigated the neural regions involved in blood pressure reactions to negative stimuli and their possible modulation by attention. Twenty-four healthy human subjects (11 females; age = 24.75 ± 2.49 years) participated in an affective perceptual load task that manipulated attention to negative/neutral distractor pictures. fMRI data were collected simultaneously with continuous recording of peripheral arterial blood pressure. A parametric modulation analysis examined the impact of attention and emotion on the relation between neural activation and blood pressure reactivity during the task. When attention was available for processing the distractor pictures, negative pictures resulted in behavioral interference, neural activation in brain regions previously related to emotion, a transient decrease of blood pressure, and a positive correlation between blood pressure response and activation in a network including prefrontal and parietal regions, the amygdala, caudate, and mid-brain. These effects were modulated by attention; behavioral and neural responses to highly negative distractor pictures (compared with neutral pictures) were smaller or diminished, as was the negative blood pressure response when the central task involved high perceptual load. Furthermore, comparing high and low load revealed enhanced activation in frontoparietal regions implicated in attention control. Our results fit theories emphasizing the role of attention in the control of behavioral and neural reactions to irrelevant emotional distracting information. Our findings furthermore extend the function of attention to the control of autonomous reactions associated with negative emotions by showing altered blood pressure reactions to emotional stimuli, the latter being of potential clinical relevance.

Evaluation of an active seating system for pressure relief.

PubMed

Koo, T K; Mak, A F; Lee, Y L

1995-01-01

In the first part of this study, the inflation-pressure and interface-pressure profiles of an active cushion system, the Talley active air bellows cushion, were examined continuously for one complete working cycle using the dynamic pressure monitor. The relationship between the inflation pressure and the interface pressure was explored. A well-defined relationship was found in the areas directly over the air bellows. In the second part of this study, the pressure-relieving characteristics of the active cushion were assessed quantitatively and compared to two types of passive cushions--the Roho high-profile air floatation cushion and the polyurethane (PU) foam cushion. Eight non-disabled subjects were positioned on the active cushion at two inflation-pressure levels--30 mmHg and 60 mmHg, or on the Roho or the PU foam cushions. Interface pressures were recorded using the Oxford pressure monitor. For the active cushion it was shown that the higher the inflation pressure was, the better the pressure-relieving characteristics seemed to be. In general, the pressure-relieving characteristics of the active cushion were not as good as those of the passive cushions being tested. The active cushion could alter the pressures over the ischial tuberosities cyclically but the amount of pressure alternation depended on the relative position of the ischial tuberosities and the air bellows.

Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations.

PubMed

Moortgat, Joachim; Schwartz, Franklin W; Darrah, Thomas H

2018-03-01

Horizontal drilling and hydraulic fracturing have enabled hydrocarbon recovery from unconventional reservoirs, but led to natural gas contamination of shallow groundwaters. We describe and apply numerical models of gas-phase migration associated with leaking natural gas wells. Three leakage scenarios are simulated: (1) high-pressure natural gas pulse released into a fractured aquifer; (2) continuous slow leakage into a tilted fractured formation; and (3) continuous slow leakage into an unfractured aquifer with fluvial channels, to facilitate a generalized evaluation of natural gas transport from faulty natural gas wells. High-pressure pulses of gas leakage into sparsely fractured media are needed to produce the extensive and rapid lateral spreading of free gas previously observed in field studies. Transport in fractures explains how methane can travel vastly different distances and directions laterally away from a leaking well, which leads to variable levels of methane contamination in nearby groundwater wells. Lower rates of methane leakage (≤1 Mcf/day) produce shorter length scales of gas transport than determined by the high-pressure scenario or field studies, unless aquifers have low vertical permeabilities (≤1 millidarcy) and fractures and bedding planes have sufficient tilt (∼10°) to allow a lateral buoyancy component. Similarly, in fractured rock aquifers or where permeability is controlled by channelized fluvial deposits, lateral flow is not sufficiently developed to explain fast-developing gas contamination (0-3 months) or large length scales (∼1 km) documented in field studies. Thus, current efforts to evaluate the frequency, mechanism, and impacts of natural gas leakage from faulty natural gas wells likely underestimate contributions from small-volume, low-pressure leakage events. © 2018, National Ground Water Association.

The evolution of blood pressure and the rise of mankind.

PubMed

Schulte, Kevin; Kunter, Uta; Moeller, Marcus J

2015-05-01

Why is it that only human beings continuously perform acts of heroism? Looking back at our evolutionary history can offer us some potentially useful insight. This review highlights some of the major steps in our evolution-more specifically, the evolution of high blood pressure. When we were fish, the first kidney was developed to create a standardized internal 'milieu' preserving the primordial sea within us. When we conquered land as amphibians, the evolution of the lung required a low systemic blood pressure, which explains why early land vertebrates (amphibians, reptiles) are such low performers. Gaining independence from water required the evolution of an impermeable skin and a water-retaining kidney. The latter was accomplished twice with two different solutions in the two major branches of vertebrate evolution: mammals excrete nitrogenous waste products as urea, which can be utilized by the kidney as an osmotic agent to produce more concentrated urine. Dinosaurs and birds have a distinct nitrogen metabolism and excrete nitrogen as water-insoluble uric acid-therefore, their kidneys cannot use urea to concentrate as well. Instead, some birds have developed the capability to reabsorb water from their cloacae. The convergent development of a separate small circulation of the lung in mammals and birds allowed for the evolution of 'high blood-pressure animals' with better capillarization of the peripheral tissues allowing high endurance performance. Finally, we investigate why mankind outperforms any other mammal on earth and why, to this day, we continue to perform acts of heroism on our eternal quest for personal bliss. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Tactile surface classification for limbed robots using a pressure sensitive robot skin.

PubMed

Shill, Jacob J; Collins, Emmanuel G; Coyle, Eric; Clark, Jonathan

2015-02-02

This paper describes an approach to terrain identification based on pressure images generated through direct surface contact using a robot skin constructed around a high-resolution pressure sensing array. Terrain signatures for classification are formulated from the magnitude frequency responses of the pressure images. The initial experimental results for statically obtained images show that the approach yields classification accuracies [Formula: see text]. The methodology is extended to accommodate the dynamic pressure images anticipated when a robot is walking or running. Experiments with a one-legged hopping robot yield similar identification accuracies [Formula: see text]. In addition, the accuracies are independent with respect to changing robot dynamics (i.e., when using different leg gaits). The paper further shows that the high-resolution capabilities of the sensor enables similarly textured surfaces to be distinguished. A correcting filter is developed to accommodate for failures or faults that inevitably occur within the sensing array with continued use. Experimental results show using the correcting filter can extend the effective operational lifespan of a high-resolution sensing array over 6x in the presence of sensor damage. The results presented suggest this methodology can be extended to autonomous field robots, providing a robot with crucial information about the environment that can be used to aid stable and efficient mobility over rough and varying terrains.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Portable air receivers and other unfired pressure vessels. 1915.172 Section 1915.172 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Portable, Unfired Pressure...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2014 CFR

2014-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2012 CFR

2012-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2013 CFR

2013-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

Code of Federal Regulations, 2011 CFR

2011-07-01

... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

Calcium impregnation of coal enriched in CO.sub.2 using high-pressure techniques

NASA Technical Reports Server (NTRS)

Gavalas, George R. (Inventor); Sharma, Pramod K. (Inventor); Voecks, Gerald E. (Inventor)

1990-01-01

Methods are described for impregnating coal with calcium carbonate by utilizing an aqueous phase ionic reaction between calcium acetate, calcium hydroxide, and water with CO.sub.2 contained within the coal. The coal is enriched in CO.sub.2 by contacting it with CO.sub.2 at high pressure, in either a continuous or pulsed mode. The inclusion of CO.sub.2 in the coal during the process does not involve evacuating the coal and subsequently absorbing CO.sub.2 onto the coal as in prior methods. Rather, the coal is treated with carbon dioxide at high pressure in a practical and viable approach. The impregnation of coal by calcium compounds not only reduces sulfur emissions by effectively tying up the sulfur as calcium sulfide or sulfate, but also increases the gasification or combustion rate. The invention also encompasses the use of other Group IIA elements, as well as the coal products resulting from the methods of treatment described.

High pressure as a probe of the solid state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruoff, A.L.

1994-07-10

It is a great pleasure and honor to receive the Percy Williams Bridgman Award. Henry Eyring, my Ph.D. advisor, instilled in me a desire to unravel the secrets of nature in the chemical and physical world. He continued what my mother had begun. From my father I learned the virtue and satisfaction of hard work. In reading Percy Bridgman's [ital The] [ital Physics] [ital of] [ital High] [ital Pressure] [1] after I came to Cornell, I became intrigued by the high-pressure variable, so I owe much to him. I received valuable assistance and encouragement from George Kennedy and Harry Drickamermore » (the first winner of the Bridgman Award) and later from Alvin Van Valkenburg (a co-inventor with three others of the diamond anvil cell). Most importantly, I received encouragement from my wife, Enid Seaton Ruoff, to carry out what is sometimes the arduous pursuit of science---a pursuit that involves long working hours---and I want especially to thank her. [copyright] 1994 American Institute of Physics« less

An environmentally-friendly, highly efficient, gas pressure-assisted sample introduction system for ICP-MS and its application to detection of cadmium and lead in human plasma.

PubMed

Cao, Yupin; Deng, Biyang; Yan, Lizhen; Huang, Hongli

2017-05-15

An environmentally friendly and highly efficient gas pressure-assisted sample introduction system (GPASIS) was developed for inductively-coupled plasma mass spectrometry. A GPASIS consisting of a gas-pressure control device, a customized nebulizer, and a custom-made spray chamber was fabricated. The advantages of this GPASIS derive from its high nebulization efficiencies, small sample volume requirements, low memory effects, good precision, and zero waste emission. A GPASIS can continuously, and stably, nebulize 10% NaCl solution for more than an hour without clogging. Sensitivity, detection limits, precision, long-term stability, double charge and oxide ion levels, nebulization efficiencies, and matrix effects of the sample introduction system were evaluated. Experimental results indicated that the performance of this GPASIS, was equivalent to, or better than, those obtained by conventional sample introduction systems. This GPASIS was successfully used to determine Cd and Pb by ICP-MS in human plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

Should we eat less salt?

PubMed

Delahaye, François

2013-05-01

High blood pressure is a major cardiovascular risk factor. There is overwhelming evidence that high salt consumption is a major cause of increased blood pressure. There is also a link between high salt consumption and risk of stroke, left ventricular hypertrophy, renal disease, obesity, renal stones and stomach cancer. Reducing salt consumption leads to a decrease in blood pressure and the incidence of cardiovascular disease. There are no deleterious effects associated with reducing salt consumption and it is also very cost-effective. Many organizations and state governments have issued recommendations regarding the suitable amount of salt consumption. In France, the objective is a salt consumption<8g/day in men and<6.5g/day in women and children. As 80% of consumed salt comes from manufactured products in developed countries, reduction of salt consumption requires the participation of the food industry. The other tool is consumer information and education. Salt consumption has already decreased in France in recent years, but efforts must continue. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

A Study by High-Speed Photography of Combustion and Knock in a Spark-Ignition Engine

NASA Technical Reports Server (NTRS)

Miller, Cearcy D

1942-01-01

The study of combustion in a spark-ignition engine given in Technical Report no. 704 has been continued. The investigation was made with the NACA high-speed motion-picture camera and the NACA optical engine indicator. The camera operates at the rate of 40,000 photographs a second and makes possible the study of phenomena occurring in time intervals as short as 0.000025 second. Photographs are presented of combustion without knock and with both light and heavy knocks, the end zone of combustion being within the field of view. Time-pressure records covering the same conditions as the photographs are presented and their relations to the photographs are studied. Photographs with ignition at various advance angles are compared with a view to observing any possible relationship between pressure and flame depth. A tentative explanation of knock is suggested, which is designed to agree with the indications of the high-speed photographs and the time-pressure records.

Investigations on the destruction of ultrasound contrast agents: Fragmentation thresholds, inertial cavitation, and bioeffects

NASA Astrophysics Data System (ADS)

Chen, Wen-Shiang

Ultrasound contrast agents (UCA) have shown great potential in both diagnostic and therapeutic applications recently. To fully explore the possible applications and the safety concerns of using UCA, a complete understanding of the UCA responses to various acoustic fields is necessary. Therefore, we performed a series of experiments and simulations to investigate the various acoustic properties of UCA with different gases and shells. We also investigated the mechanisms of some UCA-enhanced bioeffects including thrombolysis, hemolysis and high-intensity focused ultrasound (HIFU) tumor ablation. Two pressure thresholds were found: the fragmentation threshold and continuous inertial cavitation (IC) threshold. At the fragmentation threshold, bubbles were destroyed and the released gas dissolved in the surrounding solution at a rate which depended on the bubble's initial size and type of gas. The continuous IC threshold occurred at a higher pressure, where fragments of destroyed UCA (derivative bubbles) underwent violent inertial collapse; the period of activity depending on acoustic parameters such as frequency, pressure, pulse length, and pulse repetition frequency (PRF). Different UCA had different threshold pressures and demonstrated different magnitudes of IC activity after destruction. The amount of derivative bubbles generated by IC was determined by several acoustic parameters including pressure, pulse length and PRE For the same acoustic energy delivered, longer pulses generated more bubbles. More IC could be induced if the derivative bubbles could survive through the 'off' period of the pulsed ultrasound waves, and served as nuclei for the subsequent IC. In therapeutic applications, evidences of IC activity were recorded during the hemolysis, thrombolysis, and the lesion-formation processes with UCA. Hemolysis and thrombolysis were highly correlated to the presence of ultrasound and UCA, and correlated well with the amount of the IC activity. Finally, the 'tadpole-shaped' lesion formed during high-intensity, focused ultrasound treatment was the result of bubble formation by boiling.

Fuel system for rotary distributor fuel injection pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klopfer, K.H.; Kelly, W.W.

1993-06-01

In a fuel injection pump having a drive shaft, a pump rotor driven by the drive shaft, reciprocating pumping means with periodic intake and pumping strokes to periodically receive an intake charge of fuel and deliver fuel at high pressure for fuel injection is described; a distributor head with a plurality of angularly spaced distributor outlets, the pump rotor providing a distributor rotor with a distributor port connected to the pumping means, the distributor rotor being rotatably mounted in the distributor head for sequential registration of the distributor port with the distributor outlets for distributing said high pressure delivery ofmore » fuel thereto; a fuel system for supplying fuel to the pumping means, having an end chamber at one end of the pump rotor and a fuel supply pump driven by the drive shaft and having an inlet and outlet, the supply pump outlet being connected to the end chamber for supplying fuel thereto, and a pressure regulator for regulating the fuel pressure in the end chamber; and a control valve connected between the pumping means and the end chamber and selectively opened during the intake strokes to supply fuel to the pumping means from the end chamber and during the pumping strokes to spill fuel from the pumping means into the end chamber to terminate said high pressure delivery of fuel; the improvement wherein the fuel system comprises a fuel return passage connected in series with the end chamber downstream thereof, wherein the pressure regulator is mounted in the return passage for regulating the upstream fuel pressure, including the upstream fuel pressure within the end chamber, and is connected for conducting excess fuel for return to the supply pump inlet, and wherein the supply pump is driven by the drive shaft to supply fuel at a rate exceeding the rate of said high pressure delivery of fuel for fuel injection and to provide excess fuel flow continuously through the end chamber and return passage to the pressure regulator.« less

In-Vitro Performance of the Enlite Sensor in Various Glucose Concentrations during Hypobaric and Hyperbaric Conditions

PubMed Central

Adolfsson, Peter; Örnhagen, Hans; Eriksson, Bengt M.; Gautham, Raghavendhar; Jendle, Johan

2012-01-01

Background There is a need for reliable methods of glucose measurement in different environmental conditions. The objective of this in vitro study was to evaluate the performance of the Enlite® Sensor when connected to either the iPro™ Continuous Glucose Monitor recording device or the Guardian® REAL-Time transmitting device, in hypobaric and hyperbaric conditions. Methods Sixteen sensors connected to eight iPro devices and eight Guardian REAL-Time devices were immersed in three beakers containing separate glucose concentrations: 52, 88, and 207 mg/dl (2.9, 4.9, and 11.3 mmol/liter). Two different pressure tests were conducted: a hypobaric test, corresponding to maximum 18000 ft/5500 m height, and a hyperbaric test, corresponding to maximum 100 ft/30 m depth. The linearity of the sensor signals in the different conditions was evaluated. Results The sensors worked continuously, and the sensor signals were collected without interruption at all pressures tested. When comparing the input signals for glucose (ISIGs) and the different glucose concentrations during altered pressure, linearity (R2) of 0.98 was found. During the hypobaric test, significant differences (p < .005) were seen when comparing the ISIGs during varying pressure at two of the glucose concentrations (52 and 207 mg/dl), whereas no difference was seen at the 88 mg/dl glucose concentration. During the hyperbaric test, no differences were found. Conclusions The Enlite Sensors connected to either the iPro or the Guardian REAL-Time device provided values continuously. In hyperbaric conditions, no significant differences were seen during changes in ambient pressure; however, during hypobaric conditions, the ISIG was significantly different in the low and high glucose concentrations. PMID:23294783

In-vitro performance of the Enlite Sensor in various glucose concentrations during hypobaric and hyperbaric conditions.

PubMed

Adolfsson, Peter; Ornhagen, Hans; Eriksson, Bengt M; Gautham, Raghavendhar; Jendle, Johan

2012-11-01

There is a need for reliable methods of glucose measurement in different environmental conditions. The objective of this in vitro study was to evaluate the performance of the Enlite® Sensor when connected to either the iPro™ Continuous Glucose Monitor recording device or the Guardian® REAL-Time transmitting device, in hypobaric and hyperbaric conditions. Sixteen sensors connected to eight iPro devices and eight Guardian REAL-Time devices were immersed in three beakers containing separate glucose concentrations: 52, 88, and 207 mg/dl (2.9, 4.9, and 11.3 mmol/liter). Two different pressure tests were conducted: a hypobaric test, corresponding to maximum 18000 ft/5500 m height, and a hyperbaric test, corresponding to maximum 100 ft/30 m depth. The linearity of the sensor signals in the different conditions was evaluated. The sensors worked continuously, and the sensor signals were collected without interruption at all pressures tested. When comparing the input signals for glucose (ISIGs) and the different glucose concentrations during altered pressure, linearity (R(2)) of 0.98 was found. During the hypobaric test, significant differences (p < .005) were seen when comparing the ISIGs during varying pressure at two of the glucose concentrations (52 and 207 mg/dl), whereas no difference was seen at the 88 mg/dl glucose concentration. During the hyperbaric test, no differences were found. The Enlite Sensors connected to either the iPro or the Guardian REAL-Time device provided values continuously. In hyperbaric conditions, no significant differences were seen during changes in ambient pressure; however, during hypobaric conditions, the ISIG was significantly different in the low and high glucose concentrations. © 2012 Diabetes Technology Society.

Detection Angle Calibration of Pressure-Sensitive Paints

NASA Technical Reports Server (NTRS)

Bencic, Timothy J.

2000-01-01

Uses of the pressure-sensitive paint (PSP) techniques in areas other than external aerodynamics continue to expand. The NASA Glenn Research Center has become a leader in the application of the global technique to non-conventional aeropropulsion applications including turbomachinery testing. The use of the global PSP technique in turbomachinery applications often requires detection of the luminescent paint in confined areas. With the limited viewing usually available, highly oblique illumination and detection angles are common in the confined areas in these applications. This paper will describe the results of pressure, viewing and excitation angle dependence calibrations using three popular PSP formulations to get a better understanding of the errors associated with these non-traditional views.

Piston manometer as an absolute standard for vacuum-gage calibration in the range 2 to 500 millitorr

NASA Technical Reports Server (NTRS)

Warshawsky, I.

1972-01-01

A thin disk is suspended, with very small annular clearance, in a cylindrical opening in the base plate of a calibration chamber. A continuous flow of calibration gas passes through the chamber and annular opening to a downstream high vacuum pump. The ratio of pressures on the two faces of the disk is very large, so that the upstream pressure is substantially equal to net force on the disk divided by disk area. This force is measured with a dynamometer that is calibrated in place with dead weights. A probable error of + or - (0.2 millitorr plus 0.2 percent) is attainable when downstream pressure is known to 10 percent.

Conversion of laser energy to gas kinetic energy

NASA Technical Reports Server (NTRS)

Caledonia, G. E.

1975-01-01

Techniques for the gas phase absorption of laser radiation for conversion to gas kinetic energy are discussed. Absorption by inverse Bremsstrahlung, in which laser energy is converted at a gas kinetic rate in a spectrally continuous process, is briefly described, and absorption by molecular vibrational rotation bands is discussed at length. High pressure absorption is proposed as a means of minimizing gas bleaching and dissociation, the major disadvantages of the molecular absorption process. A band model is presented for predicting the molecular absorption spectra in the high pressure absorption region and is applied to the CO molecule. Use of a rare gas seeded with Fe(CO)5 for converting vibrational modes to translation modes is described.

Highly selective deuteration of pharmaceutically relevant nitrogen-containing heterocycles: a flow chemistry approach.

PubMed

Ötvös, Sándor B; Mándity, István M; Fülöp, Ferenc

2011-08-01

A simple and efficient flow-based technique is reported for the catalytic deuteration of several model nitrogen-containing heterocyclic compounds which are important building blocks of pharmacologically active materials. A continuous flow reactor was used in combination with on-demand pressure-controlled electrolytic D(2) production. The D(2) source was D(2)O, the consumption of which was very low. The experimental set-up allows the fine-tuning of pressure, temperature, and flow rate so as to determine the optimal conditions for the deuteration reactions. The described procedure lacks most of the drawbacks of the conventional batch deuteration techniques, and additionally is highly selective and reproducible.

Measuring edge-of-field water quality: Where we have been and the path forward

USDA-ARS?s Scientific Manuscript database

Heightened pressure to demonstrate the resource benefits of conservation practices and continued high-profile water quality impairments and concerns are increasing the need to quantify edge-of-field water quality. With this in mind, this manuscript summarizes previous developments in edge-of-field ...

Assessment of Corporate Management Practices in Public Universities in Kenya

ERIC Educational Resources Information Center

Waswa, Fuchaka; Ombuki, Charles; Migosi, Joash; Metet, Joseph

2013-01-01

In order to continue attracting and retaining high-class intellectual power and hence guarantee quality service delivery, public university management will need to change and adjust in line with increasing local democratisation and globalisation pressures. Scenarios that depict participatory decision-making and respect of divergent viewpoints will…

Evaluating variable rate fungicide applications for control of Sclerotinia

USDA-ARS?s Scientific Manuscript database

Oklahoma peanut growers continue to try to increase yields and reduce input costs. Perhaps the largest input in a peanut crop is fungicide applications. This is especially true for areas in the state that have high disease pressure from Sclerotinia. On average, a single fungicide application cost...

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2010 CFR

2010-04-01

... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION... polyethylene has a minimum number average molecular weight of 1,200, as determined by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total oxygen; and has an acid value of 9...

Formulation, Implementation and Validation of a Two-Fluid model in a Fuel Cell CFD Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Kunal; Cole, J. Vernon; Kumar, Sanjiv

2008-12-01

Water management is one of the main challenges in PEM Fuel Cells. While water is essential for membrane electrical conductivity, excess liquid water leads to flooding of catalyst layers. Despite the fact that accurate prediction of two-phase transport is key for optimal water management, understanding of the two-phase transport in fuel cells is relatively poor. Wang et. al. have studied the two-phase transport in the channel and diffusion layer separately using a multiphase mixture model. The model fails to accurately predict saturation values for high humidity inlet streams. Nguyen et. al. developed a two-dimensional, two-phase, isothermal, isobaric, steady state modelmore » of the catalyst and gas diffusion layers. The model neglects any liquid in the channel. Djilali et. al. developed a three-dimensional two-phase multicomponent model. The model is an improvement over previous models, but neglects drag between the liquid and the gas phases in the channel. In this work, we present a comprehensive two-fluid model relevant to fuel cells. Models for two-phase transport through Channel, Gas Diffusion Layer (GDL) and Channel-GDL interface, are discussed. In the channel, the gas and liquid pressures are assumed to be same. The surface tension effects in the channel are incorporated using the continuum surface force (CSF) model. The force at the surface is expressed as a volumetric body force and added as a source to the momentum equation. In the GDL, the gas and liquid are assumed to be at different pressures. The difference in the pressures (capillary pressure) is calculated using an empirical correlations. At the Channel-GDL interface, the wall adhesion affects need to be taken into account. SIMPLE-type methods recast the continuity equation into a pressure-correction equation, the solution of which then provides corrections for velocities and pressures. However, in the two-fluid model, the presence of two phasic continuity equations gives more freedom and more complications. A general approach would be to form a mixture continuity equation by linearly combining the phasic continuity equations using appropriate weighting factors. Analogous to mixture equation for pressure correction, a difference equation is used for the volume/phase fraction by taking the difference between the phasic continuity equations. The relative advantages of the above mentioned algorithmic variants for computing pressure correction and volume fractions are discussed and quantitatively assessed. Preliminary model validation is done for each component of the fuel cell. The two-phase transport in the channel is validated using empirical correlations. Transport in the GDL is validated against results obtained from LBM and VOF simulation techniques. The Channel-GDL interface transport will be validated against experiment and empirical correlation of droplet detachment at the interface.« less

Nurse Continuity and Hospital-Acquired Pressure Ulcers: A Comparative Analysis Using an Electronic Health Record "Big Data" Set.

PubMed

Stifter, Janet; Yao, Yingwei; Lodhi, Muhammad Kamran; Lopez, Karen Dunn; Khokhar, Ashfaq; Wilkie, Diana J; Keenan, Gail M

2015-01-01

Little research demonstrating the association between nurse continuity and patient outcomes exists despite an intuitive belief that continuity makes a difference in care outcomes. The aim of this study was to examine the association of nurse continuity with the prevention of hospital-acquired pressure ulcers (HAPU). A secondary use of data from the Hands on Automated Nursing Data System (HANDS) was performed for this comparative study. The HANDS is a nursing plan of care data set containing 42,403 episodes documented by 787 nurses, on nine units, in four hospitals and includes nurse staffing and patient characteristics. The HANDS data set resides in a "big data" relational database consisting of 89 tables and 747 columns of data. Via data mining, we created an analytic data set of 840 care episodes, 210 with and 630 without HAPUs, matched by nursing unit, patient age, and patient characteristics. Logistic regression analysis determined the association of nurse continuity and additional nurse-staffing variables on HAPU occurrence. Poor nurse continuity (unit mean continuity index = .21-.42 [1.0 = optimal continuity]) was noted on all nine study units. Nutrition, mobility, perfusion, hydration, and skin problems on admission, as well as patient age, were associated with HAPUs (p < .001). Controlling for patient characteristics, nurse continuity, and the interactions between nurse continuity and other nurse-staffing variables were not significantly associated with HAPU development. Patient characteristics including nutrition, mobility, and perfusion were associated with HAPUs, but nurse continuity was not. We demonstrated a high level of variation in the degree of continuity between patient episodes in the HANDS data, showing that it offers rich potential for future study of nurse continuity and its effect on patient outcomes.

High-Speed Videography Overview

NASA Astrophysics Data System (ADS)

Miller, C. E.

1989-02-01

The field of high-speed videography (HSV) has continued to mature in recent years, due to the introduction of a mixture of new technology and extensions of existing technology. Recent low frame-rate innovations have the potential to dramatically expand the areas of information gathering and motion analysis at all frame-rates. Progress at the 0 - rate is bringing the battle of film versus video to the field of still photography. The pressure to push intermediate frame rates higher continues, although the maximum achievable frame rate has remained stable for several years. Higher maximum recording rates appear technologically practical, but economic factors impose severe limitations to development. The application of diverse photographic techniques to video-based systems is under-exploited. The basics of HSV apply to other fields, such as machine vision and robotics. Present motion analysis systems continue to function mainly as an instant replay replacement for high-speed movie film cameras. The interrelationship among lighting, shuttering and spatial resolution is examined.

Measurement of high-pressure shock waves in cryogenic deuterium-tritium ice layered capsule implosions on NIF.

PubMed

Robey, H F; Moody, J D; Celliers, P M; Ross, J S; Ralph, J; Le Pape, S; Berzak Hopkins, L; Parham, T; Sater, J; Mapoles, E R; Holunga, D M; Walters, C F; Haid, B J; Kozioziemski, B J; Dylla-Spears, R J; Krauter, K G; Frieders, G; Ross, G; Bowers, M W; Strozzi, D J; Yoxall, B E; Hamza, A V; Dzenitis, B; Bhandarkar, S D; Young, B; Van Wonterghem, B M; Atherton, L J; Landen, O L; Edwards, M J; Boehly, T R

2013-08-09

The first measurements of multiple, high-pressure shock waves in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility have been performed. The strength and relative timing of these shocks must be adjusted to very high precision in order to keep the DT fuel entropy low and compressibility high. All previous measurements of shock timing in inertial confinement fusion implosions [T. R. Boehly et al., Phys. Rev. Lett. 106, 195005 (2011), H. F. Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] have been performed in surrogate targets, where the solid DT ice shell and central DT gas regions were replaced with a continuous liquid deuterium (D2) fill. This report presents the first experimental validation of the assumptions underlying this surrogate technique.

In Situ High Temperature High Pressure MAS NMR Study on the Crystallization of AlPO 4 -5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Zhenchao; Xu, Suochang; Hu, Mary Y.

2016-01-28

A damped oscillating crystallization process of AlPO4-5 at the presence of small amount of water is demonstrated by in situ high temperature high pressure multinuclear MAS NMR. Crystalline AlPO4-5 is formed from an intermediate semicrystalline phase via continuous rearrangement of the local structure of amorphous precursor gel. Activated water catalyzes the rearrangement via repeatedly hydrolysis and condensation reaction. Strong interactions between organic template and inorganic species facilitate the ordered rearrangement. During the crystallization process, excess water, phosphate, and aluminums are expelled from the precursor. The oscillating crystallization reflects mass transportation between the solid and liquid phase during the crystallization process.more » This crystallization process is also applicable to AlPO4-5 crystallized in the presence of a relatively large amount of water.« less

[A design and study of a novel electronic device for cuff-pressure monitoring].

PubMed

Wang, Shupeng; Li, Wei; Li, Wen; Song, Dejing; Chen, Desheng; Duan, Jun; Li, Chen; Li, Gang

2017-06-01

To design a novel electronic device for measuring the pressure in the cuff of the artificial airway; and to study the advantage of this device on continuous and intermittent cuff pressure monitoring. (1) a portable electronic device for cuff pressure measurement was invented, which could turn pressure signal into electrical signal through a pressure transducer. Meantime, it was possible to avoid pressure leak from the joint and the inside of the apparatus by modified Luer taper and sophisticated design. If the cuff pressure was out of the normal range, the apparatus could release a sound and light alarm. (2) Six traditional mechanical manometers were used to determine the cuff pressure in 6 tracheal tubes. The cuff pressure was maintain at 30 cmH 2 O (1 cmH 2 O = 0.098 kPa) by the manometer first, and repeated every 30 seconds for 4 times. (3) Study of continuous cuff pressure monitoring: We used a random number generator to randomize 6 tracheal tubes, 6 mechanical manometers and 6 our products by number 1-6, which has the same number of a group. Every group was further randomized into two balanced groups, one group used the mechanical manometer first, and the other used our product first. The baseline pressure was 30 cmH 2 O, measurement was performed every 4 hours for 6 times. When traditional mechanical manometer was used for cuff pressure monitoring, cuff pressure was decreased by an average of 2.9 cmH 2 O for each measurement (F = 728.2, P = 0.000). In study of continually monitoring, at each monitoring point, the pressure measured by electronic manometer was higher than the mechanical manometer. All the pressures measured by mechanical manometer were dropped below 20 cmH 2 O at 8th hour, and there was no pressure decrease below 20 cmH 2 O measured by electronic manometer in 24 hours by contrast. In study of intermittent monitoring, the same result was found. The pressure was dropped significantly with time when measured by mechanical manometer (F = 61.795, P = 0.000), the drops below 20 cmH 2 O began at 8th hour; but when measured by electronic manometer, all the value stayed unchanged around the baseline in 24 hours (F = 0.511, P = 0.796). Compared with traditional mechanical manometer, cuff pressures monitored by our novel electronic manometer were steadier in both continuous and intermittent monitoring. The device is compact and convenient, and can provide a good solution for continuously monitor of the tracheal cuff pressure.

Theoretical and Experimental Investigations of (I) Reaction Kinetics. (II) Theory of Liquids, and (III) Optical Rotation

DTIC Science & Technology

1975-02-14

The "region of indifference" to a phase change with pressure in camphor has been found to decrease markedly with purification. Mini (continued on...for High Pressure Transitions in d- Camphor (TI-III) and Phosphorus (I-II)", by A. F. Gabrysh, A. Vanhook and H. Eyring, J. Phys. Chem. Solids, 25, 129...on the transformation in d- camphor and phosphorus. The so-called "region of ind;ffer’e,-e" rennrted as approximately .38 kilobars in phosphorus, was

Unified approach for incompressible flows

NASA Astrophysics Data System (ADS)

Chang, Tyne-Hsien

1993-12-01

An unified approach for solving both compressible and incompressible flows was investigated in this study. The difference in CFD code development between incompressible and compressible flows is due to the mathematical characteristics. However, if one can modify the continuity equation for incompressible flows by introducing pseudocompressibility, the governing equations for incompressible flows would have the same mathematical characters as compressible flows. The application of a compressible flow code to solve incompressible flows becomes feasible. Among numerical algorithms developed for compressible flows, the Centered Total Variation Diminishing (CTVD) schemes possess better mathematical properties to damp out the spurious oscillations while providing high-order accuracy for high speed flows. It leads us to believe that CTVD schemes can equally well solve incompressible flows. In this study, the governing equations for incompressible flows include the continuity equation and momentum equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. Thus, the CTVD schemes can be implemented. In addition, the boundary conditions including physical and numerical boundary conditions must be properly specified to obtain accurate solution. The CFD code for this research is currently in progress. Flow past a circular cylinder will be used for numerical experiments to determine the accuracy and efficiency of the code before applying this code to more specific applications.

Applications of piezoelectric materials in oilfield services.

PubMed

Goujon, Nicolas; Hori, Hiroshi; Liang, Kenneth K; Sinha, Bikash K

2012-09-01

Piezoelectric materials are used in many applications in the oilfield services industry. Four illustrative examples are given in this paper: marine seismic survey, precision pressure measurement, sonic logging-while-drilling, and ultrasonic bore-hole imaging. In marine seismics, piezoelectric hydrophones are deployed on a massive scale in a relatively benign environment. Hence, unit cost and device reliability are major considerations. The remaining three applications take place downhole in a characteristically harsh environment with high temperature and high pressure among other factors. The number of piezoelectric devices involved is generally small but otherwise highly valued. The selection of piezoelectric materials is limited, and the devices have to be engineered to withstand the operating conditions. With the global demand for energy increasing in the foreseeable future, the search for hydrocarbon resources is reaching into deeper and hotter wells. There is, therefore, a continuing and pressing need for high-temperature and high-coupling piezoelectric materials.

THE CAFETERIA DIET INCREASES FAT MASS AND CHRONICALLY ELEVATES LUMBAR SYMPATHETIC NERVE ACTIVITY IN RATS

PubMed Central

Muntzel, Martin S.; Al-Naimi, Omar Ali S.; Barclay, Alicia; Ajasin, David

2012-01-01

Obesity causes sympathetic activation that promotes atherosclerosis, end-organ damage, and hypertension. Because high-fat induced weight gain in rats elevates plasma leptin at 1–3 days following onset of calorie dense diets, we hypothesized that diet-induced overfeeding will increase sympathetic activity within one week following onset of the regimen. To test this, we continuously measured sympathetic activity and blood pressure before and during the onset of diet-induced obesity using a high calorie cafeteria-style diet. Female Wistar rats, in which radiotelemeters had been implanted for continuous monitoring of lumbar sympathetic activity, mean arterial pressure, and heart rate, were randomly assigned to groups that received regular chow (control) or a cafeteria diet for a period of 15 days. This short-term cafeteria-feeding regimen caused modest but non-significant increases in body weight (P = 0.07) and a doubling of brown and white adipose tissue (P < 0.01). The increases in fat mass were accompanied by elevations in plasma leptin (P < 0.001) but no change in glucose. Overall heart rates and blood pressure were higher in cafeteria rats compared with controls (P < 0.05). Cafeteria diet-induced weight gain caused increases in lumbar sympathetic nerve activity that became significant by the 12th day of the diet (p < 0.001). These data show, for the first time, that the high-fat cafeteria-style diet stimulates sustained increases in lumbar sympathetic neural drive in rats. PMID:23090774

Three types of cavitation caused by air seeding.

PubMed

Shen, Fanyi; Wang, Yuansheng; Cheng, Yanxia; Zhang, Li

2012-11-01

There are different opinions of the dynamics of an air bubble entering a xylem conduit. In this paper, we present a thorough mechanical analysis and conclude that there are three types of cavitation caused by air seeding. After an air seed enters a conduit at high xylem pressure P'(1), along with the drop of the water potential, it will expand gradually to a long-shaped bubble and extend continually. This is the first type of air seeding, or the type of expanding gradually. When the xylem pressure is moderate, right after an air seed enters a conduit, it will expand first. Then, as soon as the pressure reaches a threshold the bubble will blow up to form a bubble in long shape, accompanied by acoustic (or ultra-acoustic) emission. It will extend further as xylem pressure decreases continually. This is the second type of air seeding, or the type of expanding-exploding, becoming a long-shaped bubble-lengthening by degrees. In the range of P'(1) ≤ - 3P(o) (P(o) is atmospheric pressure), soon after an air seed is sucked into a conduit it will explode immediately and the conduit will be full of the gas of the bubble instantly. This is the third type of air seeding, or the type of sudden exploding and filling conduit instantly. The third type is the frequent event in daily life of plant.

Culturable prokaryotic diversity of deep, gas hydrate sediments: first use of a continuous high-pressure, anaerobic, enrichment and isolation system for subseafloor sediments (DeepIsoBUG)

PubMed Central

Parkes, R John; Sellek, Gerard; Webster, Gordon; Martin, Derek; Anders, Erik; Weightman, Andrew J; Sass, Henrik

2009-01-01

Deep subseafloor sediments may contain depressurization-sensitive, anaerobic, piezophilic prokaryotes. To test this we developed the DeepIsoBUG system, which when coupled with the HYACINTH pressure-retaining drilling and core storage system and the PRESS core cutting and processing system, enables deep sediments to be handled without depressurization (up to 25 MPa) and anaerobic prokaryotic enrichments and isolation to be conducted up to 100 MPa. Here, we describe the system and its first use with subsurface gas hydrate sediments from the Indian Continental Shelf, Cascadia Margin and Gulf of Mexico. Generally, highest cell concentrations in enrichments occurred close to in situ pressures (14 MPa) in a variety of media, although growth continued up to at least 80 MPa. Predominant sequences in enrichments were Carnobacterium, Clostridium, Marinilactibacillus and Pseudomonas, plus Acetobacterium and Bacteroidetes in Indian samples, largely independent of media and pressures. Related 16S rRNA gene sequences for all of these Bacteria have been detected in deep, subsurface environments, although isolated strains were piezotolerant, being able to grow at atmospheric pressure. Only the Clostridium and Acetobacterium were obligate anaerobes. No Archaea were enriched. It may be that these sediment samples were not deep enough (total depth 1126–1527 m) to obtain obligate piezophiles. PMID:19694787

A new device for administration of continuous positive airway pressure in preterm infants: comparison with a standard nasal CPAP continuous positive airway pressure system.

PubMed

Trevisanuto, Daniele; Grazzina, Nicoletta; Doglioni, Nicoletta; Ferrarese, Paola; Marzari, Francesco; Zanardo, Vincenzo

2005-06-01

We compared the effectiveness of a new continuous positive airway pressure (CPAP) device (neonatal helmet CPAP) with a conventional nasal CPAP system in preterm neonates needing continuous distending pressure. Randomized, physiological, cross-over study in a tertiary referral, neonatal intensive care unit in a university teaching hospital. Twenty very low birth weight infants with a postnatal age greater than 24 h who were receiving nasal CPAP for apnea and/or mild respiratory distress were enrolled. CPAP delivered by neonatal helmet CPAP and nasal CPAP in random order for two subsequent 90-min periods. Were continuously measured the Neonatal Infant Pain Scale (NIPS) score, oxygen requirements, respiratory rate, heart rate, oxygen saturation, transcutaneous PO(2) (tcPO(2)) and PCO(2) (tcPCO(2)), blood pressure, and desaturations. NIPS scores were significantly lower when the infants were on the neonatal helmet CPAP than when they were on nasal CPAP (0.26+/-0.07 vs. 0.63+/-0.12). The other studied parameters did not differ between the two CPAP modes. The number of desaturations was reduced during the neonatal helmet CPAP treatment (18 vs. 32), although this difference was not significant. In this short-term physiological study the neonatal helmet CPAP appears to be as good as the golden standard for managing preterm infants needing continuous distending pressure, with enhanced tolerability. Further evaluation in a randomized clinical trial is needed to confirm these findings.

Pressure-tuned superconductivity and normal-state behavior in Ba (Fe0.943Co0.057)2As2 near the antiferromagnetic boundary

NASA Astrophysics Data System (ADS)

Liu, W.; Wu, Y. F.; Li, X. J.; Bud'ko, S. L.; Canfield, P. C.; Panagopoulos, C.; Li, P. G.; Mu, G.; Hu, T.; Almasan, C. C.; Xiao, H.

2018-04-01

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba (Fe1-xCox) 2As2 single crystals with x =0.057 , which is near the antiferromagnetic instability. Resistivity ρ =ρ0+A Tn was studied under applied pressure up to 7.90 GPa. The parameter n approaches a minimum value of n ≈1 at a critical pressure Pc=3.65 GPa. Near Pc, the superconducting transition temperature Tc reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. These results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum Tc.

Psycho-Circulatory Responses Caused by Listening to Music, and Exposure to Fluctuating Noise or Steady Noise

NASA Astrophysics Data System (ADS)

SAKAMOTO, H.; HAYASHI, F.; SUGIURA, S.; TSUJIKAWA, M.

2002-02-01

This study investigated the effect of steady noise, fluctuating noise and music on circulatory function. Pulse-wave and blood pressure were continuously measured in 35 healthy young females who listened to three types of music or were exposed to steady noise or fluctuating noise, synchronized with each type of music with respect to intensity variations. The pulse-wave did not change during any exposure conditions. Regarding blood pressure, several modes were observed. The critical level for a blood pressure change was estimated to be 54 LAeqduring exposure to steady noise. The frequency of high-intensity peaks in the mode of sound fluctuation was associated with elevation in blood pressure. The blood pressure change was analyzed by distinguishing the intensity variation in sound fluctuation from other attributes of music. The effects of music on blood pressure were modified not only by the melody and timbre of the music but also by emotional responses during listing.

Continuous long-term measurements of the middle ear pressure in subjects without a history of ear disease.

PubMed

Tideholm, B; Carlborg, B; Jönsson, S; Bylander-Groth, A

1998-06-01

A new method was used for continuous measurement of the middle ear (ME) pressure during a 24-h period. In 10 subjects without a history of ear disease a small perforation was made through the tympanic membrane. A tight rubber stopper containing a small polyethylene tube was fitted into the external ear canal. Conventional tubal function tests were performed. The equipment was then carried by the subjects for 24 h of normal activity to monitor any slow or rapid dynamic pressure change in the ME. Body position was found to be the most important factor affecting ME pressure variation, during the 24-h continuous pressure measurements. A significant pressure rise occurred in the recumbent position in all but one subject. Few rapid pressure equilibrations were seen during the recordings, indicating few tubal openings. This implies that the pressure changes in the ME seen in this study were mainly the result of gas exchange over the mucosa. The investigation might be a base for reference when investigating different kinds of pathologic conditions in the ear.

Stabilization of Softwood-Derived Pyrolysis Oils for Continuous Bio-oil Hydroprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olarte, Mariefel V.; Zacher, Alan H.; Padmaperuma, Asanga B.

The use of fast pyrolysis as a potential renewable liquid transportation fuel alternative to crude oil depends on successful catalytic upgrading to produce a refinery-ready product with oxygen content and qualities (i.e. specific functional group or compound content) that is compatible with the product’s proposed insertion point. Catalytic upgrading of bio-oil requires high temperature and pressure, while similar to crude oil hydrotreating, is not as straightforward for the thermally unstable pyrolysis oil. For years, a two-temperature zone, downflow trickle bed reactor was the state-of-the art for continuous operation. However, pressure excursion due to plug formation still occurred, typically at themore » high temperature transition zone, leading to a process shutdown within 140 h. Recently, a bio-oil pre-treatment process, together with a robust commercial catalyst, was found to be enabling the continuous operation of the two-zone hydroprocessing system. Here, we report the results on pre-treating bio-oil at 413 K and 8.4 MPa of flowing H2 (500 L H2/L bio-oil, 0.5 L bio-oil/L catalyst bed) and the attempts to characterize this oil product to understand the chemistry which enabled the long-term processing of bio-oil.« less

Structure of Oxide Glass and Melts at High-Pressure: A View from Inelastic X-ray Scattering and 2D Solid-State NMR

NASA Astrophysics Data System (ADS)

Lee, S.; Mysen, B. O.; Fei, Y.; Cody, G. D.; Mao, H.; Eng, P.

2006-12-01

Full understanding of the atomic arrangement of oxides glasses and melts both at ambient and high-pressure has long been one of the fundamental and yet difficult problems in earth sciences, condensed matter physics as well as glass sciences. The structures of archetypal oxide glasses (e.g. SiO2 and B2O3) as well as complex silicate glasses (ternary and quaternary aluminosilicate glasses) at high pressure are essential to elucidate origins of anomalous macroscopic properties of melts and global geophysical processes in the Earth's interior. Recent progress in inelastic x-ray scattering (IXS) with high brilliance 3rd generation synchrotron x-rays combined with DAC techniques allows us to explore pressure-induced changes in the bonding nature of archetypal amorphous oxide, illustrating a new opportunity to study amorphous oxides with IXS (Lee SK et al. Nature Materials 2005, 4, p851). 2 dimensional solid-state NMR have offered much improved resolution over conventional 1D NMR, unveiling previously unknown structural details of amorphous silicates at high pressure (Lee SK. Geochim. Cosmochim. Acta 2005, 69, p3695; J. Phys. Chem. B. 2006, 110, p16408) Here, we report the synchrotron inelastic x-ray scattering results (oxygen and boron K-edge) for divers oxide glasses at pressure up to 40 GPa, revealing the nature of pressure-induced bonding changes and the structure. Direct in-situ measurements provide evidence for a continuous transformation with multiple densification mechanisms. 2D solid-state NMR spectra for silicate and germinate glasses shows detailed information about extent of disorder among framework units at high pressure. The chemical ordering among framework units leads to the formation of ^{[5,6]}Si-O-^{[4]}Si in silicates and ^{[5,6]}Al-O-^{[4]}Si in aluminosilicates. Whereas the densification mechanism can be dependent on the chemical composition and the fraction of non-bridging oxygen, the pressure dependence of both simple and complex multi-component silicate glasses showed similar characteristics: low pressure regime was marked with topological variation without coordination transformation and inter-mediate pressure region (about 5-10 GPa) was characterized by the largest (d(^{[4]}B or ^{[5,6]}Si)/dP) value. Finally high-pressure regime (above 10 GPa) was characterized by a larger energy penalty for coordination transformation than in intermediate pressure regime. These results provide improved prospect for the bonding nature of amorphous materials at high pressure using synchrotron inelastic x-ray scattering and 2D NMR and aid in understanding the microscopic origins of the properties of melts and geological processes in the Earth's interior.

System and method for continuous solids slurry depressurization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leininger, Thomas Frederick; Steele, Raymond Douglas; Cordes, Stephen Michael

A system includes a first pump having a first outlet and a first inlet, and a controller. The first pump is configured to continuously receive a flow of a slurry into the first outlet at a first pressure and to continuously discharge the flow of the slurry from the first inlet at a second pressure less than the first pressure. The controller is configured to control a first speed of the first pump against the flow of the slurry based at least in part on the first pressure, wherein the first speed of the first pump is configured to resistmore » a backflow of the slurry from the first outlet to the first inlet.« less

Dual-modality arterial pulse monitoring system for continuous blood pressure measurement.

PubMed

Wen-Xuan Dai; Yuan-Ting Zhang; Jing Liu; Xiao-Rong Ding; Ni Zhao

2016-08-01

Accurate and ambulatory measurement of blood pressure (BP) is essential for efficient diagnosis, management and prevention of cardiovascular diseases (CVDs). However, traditional cuff-based BP measurement methods provide only intermittent BP readings and can cause discomfort with the occlusive cuff. Although pulse transit time (PTT) method is promising for cuffless and continuous BP measurement, its pervasive use is restricted by its limited accuracy and requirement of placing sensors on multiple body sites. To tackle these issues, we propose a novel dual-modality arterial pulse monitoring system for continuous blood pressure measurement, which simultaneously records the pressure and photoplethysmography (PPG) signals of radial artery. The obtained signals can be used to generate a pressure-volume curve, from which the elasticity index (EI) and viscosity index (VI) can be extracted. Experiments were carried out among 7 healthy subjects with their PPG, ECG, arterial pressure wave and reference BP collected to examine the effectiveness of the proposed indexes. The results of this study demonstrate that a linear regression model combining EI and VI has significantly higher BP tracking correlation coefficient as compared to the PTT method. This suggests that the proposed system and method can potentially be used for convenient and continuous blood pressure estimation with higher accuracy.

Use of submersible pressure transducers in water-resources investigations

USGS Publications Warehouse

Freeman, Lawrence A.; Carpenter, Michael C.; Rosenberry, Donald O.; Rousseau, Joseph P.; Unger, Randy; McLean, John S.

2004-01-01

Submersible pressure transducers, developed in the early 1960s, have made the collection of water-level and pressure data much more convenient than former methods. Submersible pressure transducers, when combined with electronic data recorders have made it possible to collect continuous or nearly continuous water-level or pressure data from wells, piezometers, soil-moisture tensiometers, and surface water gages. These more frequent measurements have led to an improved understanding of the hydraulic processes in streams, soils, and aquifers. This manual describes the operational theory behind submersible pressure transducers and provides information about their use in hydrologic investigations conducted by the U.S. Geological Survey.

Reservoir response to thermal and high-pressure well stimulation efforts at Raft River, Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plummer, Mitchell; Bradford, Jacob; Moore, Joseph

An injection stimulation test begun at the Raft River geothermal reservoir in June, 2013 has produced a wealth of data describing well and reservoir response via high-resolution temperature logging and distributed temperature sensing, seismic monitoring, periodic borehole televiewer logging, periodic stepped flow rate tests and tracer injections before and after stimulation efforts. One of the primary measures of response to the stimulation is the relationship between fluid pressure and flow rate, short-term during forced flow rate changes and the long-term change in injectivity. In this paper we examine that hydraulic response using standard pumping test analysis methods, largely because pressuremore » response to the stimulation was not detected, or measurable, in other wells. Analysis of stepped rate flow tests supports the inference from other data that a large fracture, with a radial extent of one to several meters, intersects the well in the target reservoir, suggests that the flow regime is radial to a distance of only several meters and demonstrates that the pressure build-up cone reaches an effective constant head at that distance. The well’s longer term hydraulic response demonstrated continually increasing injectivity but at a dramatically faster rate later from ~2 years out and continuing to the present. The net change in injectivity is significantly greater than observed in other longterm injectivity monitoring studies, with an approximately 150–fold increase occurring over ~2.5 years. While gradually increasing injectivity is a likely consequence of slow migration of a cooling front, and consequent dilation of fractures, the steady, ongoing, rate of increase is contrary to what would be expected in a radial or linear flow regime, where the cooling front would slow with time. As a result, occasional step-like changes in injectivity, immediately following high-flow rate tests suggest that hydro shearing during high-pressure testing altered the near-well permeability structure.« less

Revealing nanoparticle assembly under high pressure.

NASA Astrophysics Data System (ADS)

Fan, Hongyou

Precise control of structural parameters through nanoscale engineering to improve optical and electronic properties of functional nanoparticles continuously remains an outstanding challenge. Previous work on nanoparticle assembly has been conducted largely at ambient pressure. Here I will present a new Stress-Induced Fabrication method in which we applied high pressure or stress to nanoparticle arrays to induce structural phase transition and to consolidate new nanomaterials with precisely controlled structures and tunable properties. By manipulating nanoparticle coupling through external pressure, a reversible change in their assemblies and properties can be achieved and demonstrated. In addition, over a certain threshold, the external pressure will force these nanoparticles into contact, thereby allowing the formation and consolidation of one- to three-dimensional nanostructures. Through stress induced nanoparticle assembly, materials engineering and synthesis become remarkably flexible without relying on traditional crystallization process where atoms/ions are locked in a specific crystal structure. Therefore, morphology or architecture can be readily tuned to produce desirable properties for practical applications. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

The Age-Dependent Relationship between Blood Pressure and Cognitive Impairment: A Cross-Sectional Study in a Rural Area of Xi'an, China.

PubMed

Shang, Suhang; Li, Pei; Deng, Meiying; Jiang, Yu; Chen, Chen; Qu, Qiumin

2016-01-01

Hypertension is a modifiable risk factor for cognitive impairment, although the relationship between hypertension and cognitive impairment is not fully understood. The objective of this study was to investigate the effect of age on the relationship between blood pressure and cognitive impairment. Blood pressure and global cognitive function information was collected from 1799 participants (age 40-85) who lived in a village in the suburbs of Xi'an, China, during in-person interviews. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than the cutoff value. The effect of age on the relationship between blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and high blood pressure (HBP, SBP≥140 mm Hg and/or DBP≥90 mm Hg)] and cognitive impairment was analyzed by logistic regression models using interaction and stratified analysis. Blood pressure and age were regarded as both continuous and categorical data. A total of 231 participants were diagnosed as having cognitive impairment based on our criteria. Interaction analysis for the total population showed that SBP (when regarded as continuous data) was positively correlated with cognitive impairment (OR = 1.130 [95% CI, 1.028-1.242] per 10mmHg, P = 0.011); however, the age by SBP interaction term was negatively correlated with cognitive impairment (OR = 0.989 [95% CI, 0.982-0.997] per 10mmHg×year, P = 0.006), indicating that the relationship between SBP and cognitive impairment was age-dependent (OR = 1.130×0.989(age-55.5) per 10mmHg,40 ≤age≤85). When the blood pressure and age were considered as binary data, the results were similar to those obtained when they were considered as continuous variables. Stratified multivariate analysis revealed that the relationship between SBP (when regarded as continuous data) and cognitive impairment was positive for patients aged 40-49 years (OR = 1.349 [95% CI: 1.039-1.753] per 10mmHg, P = 0.025) and 50-59 years (OR = 1.185 [95% CI: 1.028-1.366] per 10mmHg, P = 0.019), whereas it tended to be negative for patients aged 60-69 years (OR = 0.878 [95% CI: 0.729-1.058] per 10mmHg, P = 0.171) and ≥70 years (OR = 0.927 [95% CI: 0.772-1.113] per 10mmHg, P = 0.416). Results similar to those for SBP were obtained for DBP, MABP and HBP as well. Subsequently, SBP, DBP and MABP were transformed into categorical data (SBP<140mmHg, 140mmHg≤SBP<160mmHg, and SBP≥160mmHg; DBP<90mmHg, 90mmHg≤DBP<100mmHg, and DBP≥100mmHg; MABP<100mmHg, 100mmHg≤MABP<110mmHg, and MABP≥110mmHg), and the stratified multivariate analysis was repeated. This analysis showed that the age-dependent association continued to exist and was especially prominent in the SBP≥160 mmHg, DBP≥90 mmHg and MABP≥110 mmHg groups. Elevated blood pressure is positively correlated with cognitive impairment in the middle-aged, but this positive association declines with increasing age. These results indicated that specific blood pressure management strategies for various age groups may be crucial for maintaining cognitive vitality.

The Age-Dependent Relationship between Blood Pressure and Cognitive Impairment: A Cross-Sectional Study in a Rural Area of Xi'an, China

PubMed Central

Shang, Suhang; Li, Pei; Deng, Meiying; Jiang, Yu; Chen, Chen; Qu, Qiumin

2016-01-01

Background Hypertension is a modifiable risk factor for cognitive impairment, although the relationship between hypertension and cognitive impairment is not fully understood. The objective of this study was to investigate the effect of age on the relationship between blood pressure and cognitive impairment. Methods Blood pressure and global cognitive function information was collected from 1799 participants (age 40–85) who lived in a village in the suburbs of Xi'an, China, during in-person interviews. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than the cutoff value. The effect of age on the relationship between blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and high blood pressure (HBP, SBP≥140 mm Hg and/or DBP≥90 mm Hg)] and cognitive impairment was analyzed by logistic regression models using interaction and stratified analysis. Blood pressure and age were regarded as both continuous and categorical data. Results A total of 231 participants were diagnosed as having cognitive impairment based on our criteria. Interaction analysis for the total population showed that SBP (when regarded as continuous data) was positively correlated with cognitive impairment (OR = 1.130 [95% CI, 1.028–1.242] per 10mmHg, P = 0.011); however, the age by SBP interaction term was negatively correlated with cognitive impairment (OR = 0.989 [95% CI, 0.982–0.997] per 10mmHg×year, P = 0.006), indicating that the relationship between SBP and cognitive impairment was age-dependent (OR = 1.130×0.989(age-55.5) per 10mmHg,40 ≤age≤85). When the blood pressure and age were considered as binary data, the results were similar to those obtained when they were considered as continuous variables. Stratified multivariate analysis revealed that the relationship between SBP (when regarded as continuous data) and cognitive impairment was positive for patients aged 40–49 years (OR = 1.349 [95% CI: 1.039–1.753] per 10mmHg, P = 0.025) and 50–59 years (OR = 1.185 [95% CI: 1.028–1.366] per 10mmHg, P = 0.019), whereas it tended to be negative for patients aged 60–69 years (OR = 0.878 [95% CI: 0.729–1.058] per 10mmHg, P = 0.171) and ≥70 years (OR = 0.927 [95% CI: 0.772–1.113] per 10mmHg, P = 0.416). Results similar to those for SBP were obtained for DBP, MABP and HBP as well. Subsequently, SBP, DBP and MABP were transformed into categorical data (SBP<140mmHg, 140mmHg≤SBP<160mmHg, and SBP≥160mmHg; DBP<90mmHg, 90mmHg≤DBP<100mmHg, and DBP≥100mmHg; MABP<100mmHg, 100mmHg≤MABP<110mmHg, and MABP≥110mmHg), and the stratified multivariate analysis was repeated. This analysis showed that the age-dependent association continued to exist and was especially prominent in the SBP≥160 mmHg, DBP≥90 mmHg and MABP≥110 mmHg groups. Conclusions Elevated blood pressure is positively correlated with cognitive impairment in the middle-aged, but this positive association declines with increasing age. These results indicated that specific blood pressure management strategies for various age groups may be crucial for maintaining cognitive vitality. PMID:27438476

High-Pressure Gaseous Burner (HPGB) Facility Completed for Quantitative Laser Diagnostics Calibration

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet

2002-01-01

A gas-fueled high-pressure combustion facility with optical access, which was developed over the last 2 years, has just been completed. The High Pressure Gaseous Burner (HPGB) rig at the NASA Glenn Research Center can operate at sustained pressures up to 60 atm with a variety of gaseous fuels and liquid jet fuel. The facility is unique as it is the only continuous-flow, hydrogen-capable, 60-atm rig in the world with optical access. It will provide researchers with new insights into flame conditions that simulate the environment inside the ultra-high-pressure-ratio combustion chambers of tomorrow's advanced aircraft engines. The facility provides optical access to the flame zone, enabling the calibration of nonintrusive optical diagnostics to measure chemical species and temperature. The data from the HPGB rig enables the validation of numerical codes that simulate gas turbine combustors, such as the National Combustor Code (NCC). The validation of such numerical codes is often best achieved with nonintrusive optical diagnostic techniques that meet these goals: information-rich (multispecies) and quantitative while providing good spatial and time resolution. Achieving these goals is a challenge for most nonintrusive optical diagnostic techniques. Raman scattering is a technique that meets these challenges. Raman scattering occurs when intense laser light interacts with molecules to radiate light at a shifted wavelength (known as the Raman shift). This shift in wavelength is unique to each chemical species and provides a "fingerprint" of the different species present. The facility will first be used to gather a comprehensive data base of laser Raman spectra at high pressures. These calibration data will then be used to quantify future laser Raman measurements of chemical species concentration and temperature in this facility and other facilities that use Raman scattering.

Development of a high power microwave thruster, with a magnetic nozzle, for space applications

NASA Technical Reports Server (NTRS)

Power, John L.; Chapman, Randall A.

1989-01-01

This paper describes the current development of a high-power microwave electrothermal thruster (MET) concept at the NASA Lewis Research Center. Such a thruster would be employed in space for applications such as orbit raining, orbit maneuvering, station change, and possibly trans-lunar or trans-planetary propulsion of spacecraft. The MET concept employs low frequency continuous wave (CW) microwave power to create and continuously pump energy into a flowing propellant gas at relative high pressure via a plasma discharge. The propellant is heated to very high bulk temperatures while passing through the plasma discharge region and then is expanded through a throat-nozzle assembly to produce thrust, as in a conventional rocket engine. Apparatus, which is described, is being assembled at NASA Lewis to test the MET concept to CW power levels of 30 kW at a frequency of 915 MHz. The microwave energy is applied in a resonant cavity applicator and is absorbed by a plasma discharge in the flowing propellant. The ignited plasma acts as a lossy load, and with optimal tuning, energy absorption efficiencies over 95 percent (based on the applied microwave power) are expected. Nitrogen, helium, and hydrogen will be tested as propellants in the MET, at discharge chamber pressures to 10 atm.

Formation of collapsed tetragonal phase in EuCo₂As₂ under high pressure.

PubMed

Bishop, Matthew; Uhoya, Walter; Tsoi, Georgiy; Vohra, Yogesh K; Sefat, Athena S; Sales, Brian C

2010-10-27

The structural properties of EuCo₂As₂ have been studied up to 35 GPa, through the use of x-ray diffraction in a diamond anvil cell at a synchrotron source. At ambient conditions, EuCo₂As₂ ) (I4/mmm) has a tetragonal lattice structure with a bulk modulus of 48 ± 4 GPa. With the application of pressure, the a axis exhibits negative compressibility with a concurrent sharp decrease in c-axis length. The anomalous compressibility of the a axis continues until 4.7 GPa, at which point the structure undergoes a second-order phase transition to a collapsed tetragonal (CT) state with a bulk modulus of 111 ± 2 GPa. We found a strong correlation between the ambient pressure volume of 122 parents of superconductors and the corresponding tetragonal to collapsed tetragonal phase transition pressures.

Monte Carlo Uncertainty Quantification for an Unattended Enrichment Monitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarman, Kenneth D.; Smith, Leon E.; Wittman, Richard S.

As a case study for uncertainty analysis, we consider a model flow monitor for measuring enrichment in gas centrifuge enrichment plants (GCEPs) that could provide continuous monitoring of all declared gas flow and provide high-accuracy gas enrichment estimates as a function of time. The monitor system could include NaI(Tl) gamma-ray spectrometers, a pressure signal-sharing device to be installed on an operator\\rq{}s pressure gauge or a dedicated inspector pressure sensor, and temperature sensors attached to the outside of the header pipe, to provide pressure, temperature, and gamma-ray spectra measurements of UFmore » $$_6$$ gas flow through unit header pipes. Our study builds on previous modeling and analysis methods development for enrichment monitor concepts and a software tool that was developed at Oak Ridge National Laboratory to generate and analyze synthetic data.« less

Development of Gradient Compression Garments for Protection Against Post Flight Orthostatic Intolerance

NASA Technical Reports Server (NTRS)

Stenger, M. B.; Lee, S. M. C.; Westby, C. M.; Platts, S. H.

2010-01-01

Orthostatic intolerance after space flight is still an issue for astronaut health. No in-flight countermeasure has been 100% effective to date. NASA currently uses an inflatable anti-gravity suit (AGS) during reentry, but this device is uncomfortable and loses effectiveness upon egress from the Shuttle. The Russian Space Agency currently uses a mechanical counter-pressure garment (Kentavr) that is difficult to adjust alone, and prolonged use may result in painful swelling at points where the garment is not continuous (feet, knees, and groin). To improve comfort, reduce upmass and stowage requirements, and control fabrication and maintenance costs, we have been evaluating a variety of gradient compression, mechanical counter-pressure garments, constructed from spandex and nylon, as a possible replacement for the current AGS. We have examined comfort and cardiovascular responses to knee-high garments in normovolemic subjects; thigh-high garments in hypovolemic subjects and in astronauts after space flight; and 1-piece, breast-high garments in hypovolemic subjects. These gradient compression garments provide 55 mmHg of compression over the ankle, decreasing linearly to 35 mmHg at the knee. In thigh-high versions the compression continues to decrease to 20 mmHg at the top of the leg, and for breast-high versions, to 15 mmHg over the abdomen. Measures of efficacy include increased tilt survival time, elevated blood pressure and stroke volume, and lower heart-rate response to orthostatic stress. Results from these studies indicate that the greater the magnitude of compression and the greater the area of coverage, the more effective the compression garment becomes. Therefore, we are currently testing a 3-piece breast-high compression garment on astronauts after short-duration flight. We chose a 3-piece garment consisting of thigh-high stockings and shorts, because it is easy to don and comfortable to wear, and should provide the same level of protection as the 1-piece breast-high garments evaluated in hypovolemic test subjects.

Pump out the volume--The effect of tracheal and subelytral pressure pulses on convective gas exchange in a dung beetle, Circellium bacchus (Fabricus).

PubMed

Duncan, Frances D; Förster, Thomas D; Hetz, Stefan K

2010-05-01

Many flightless beetles like the large apterous dung beetle Circellium bacchus, possess a subelytral cavity (SEC) providing an extra air space below the elytra which connects to the tracheal system (TS) via metathoracic and abdominal spiracles. By measuring subelytral and intratracheal pressure as well as body movements and gas exchange simultaneously in a flow-through setup, we investigated the contribution of convection on Circellium respiratory gas exchange. No constriction phase was observed. TS and SEC pressures were always around atmospheric values. During interburst phase open abdominal spiracles and a leaky SEC led to small CO(2)-peaks on a continuous CO(2) baseline, driven by intermittent positive tracheal pressure peaks in anti-phase with small negative subelytral pressure peaks caused by dorso-ventral tergite action. Spiracle opening was accompanied by two types of body movements. Higher frequency telescoping body movements at the beginning of opening resulted in high amplitude SEC and TS pressure peaks. High frequency tergite movements caused subelytral pressure peaks and led to a saw tooth like CO(2) release pattern in a burst. We propose that during the burst open mesothoracic spiracles increase the compliance of the subelytral cavity allowing big volumes of tracheal air being pulled out by convection. Copyright 2009 Elsevier Ltd. All rights reserved.

High Yield Chemical Vapor Deposition Growth of High Quality Large-Area AB Stacked Bilayer Graphene

PubMed Central

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Yu, Woo Jong; Liu, Yuan; Chen, Yu; Shaw, Jonathan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

2012-01-01

Bernal stacked (AB stacked) bilayer graphene is of significant interest for functional electronic and photonic devices due to the feasibility to continuously tune its band gap with a vertical electrical field. Mechanical exfoliation can be used to produce AB stacked bilayer graphene flakes but typically with the sizes limited to a few micrometers. Chemical vapor deposition (CVD) has been recently explored for the synthesis of bilayer graphene but usually with limited coverage and a mixture of AB and randomly stacked structures. Herein we report a rational approach to produce large-area high quality AB stacked bilayer graphene. We show that the self-limiting effect of graphene growth on Cu foil can be broken by using a high H2/CH4 ratio in a low pressure CVD process to enable the continued growth of bilayer graphene. A high temperature and low pressure nucleation step is found to be critical for the formation of bilayer graphene nuclei with high AB stacking ratio. A rational design of a two-step CVD process is developed for the growth of bilayer graphene with high AB stacking ratio (up to 90 %) and high coverage (up to 99 %). The electrical transport studies demonstrated that devices made of the as-grown bilayer graphene exhibit typical characteristics of AB stacked bilayer graphene with the highest carrier mobility exceeding 4,000 cm2/V·s at room temperature, comparable to that of the exfoliated bilayer graphene. PMID:22906199

Randomised controlled cross-over comparison of continuous positive airway pressure through the Hamilton Galileo ventilator with a Dräger CF 800 device.

PubMed

Sutton, P J; Perkins, C L; Giles, S P; McAuley, D F; Gao, F

2005-01-01

In this controlled, randomised cross-over trial on 26 intensive care patients, we compared the effects on haemodynamic and respiratory profiles of continuous positive airway pressure delivered through the Hamilton Galileo ventilator or a Drager CF 800 device. We also compared the nursing time saved using the two approaches when weaning patients from mechanical ventilation. We did not find significant differences in haemodynamics, respiratory rate, physiological dead space, oxygen saturation and carbon dioxide production between the continuous positive airway pressure generated by the Galileo and Drager machines. However, there was a 10-fold reduction in nursing time using the Galileo ventilator compared with the Drager generator. We conclude that continuous positive airway pressure delivered through the Galileo ventilator is as efficient as a Drager device but consumes less nursing time.

Automated electronic monitoring of circuit pressures during continuous renal replacement therapy: a technical report.

PubMed

Zhang, Ling; Baldwin, Ian; Zhu, Guijun; Tanaka, Aiko; Bellomo, Rinaldo

2015-03-01

Automated electronic monitoring and analysis of circuit pressures during continuous renal replacement therapy (CRRT) has the potential to predict failure and allow intervention to optimise function. Current CRRT machines can measure and store pressure readings for downloading into databases and for analysis. We developed a procedure to obtain such data at intervals of 1 minute and analyse them using the Prismaflex CRRT machine, and we present an example of such analysis. We obtained data on pressures obtained at intervals of 1 minute in a patient with acute kidney injury and sepsis treated with continuous haemofiltration at 2 L/hour of ultrafiltration and a blood flow of 200 mL/minute. Data analysis identified progressive increases in transmembrane pressure (TMP) and prefilter pressure (PFP) from time 0 until 33 hours or clotting. TMP increased from 104 mmHg to 313 mmHg and PFP increased from from 131 mmHg to 185 mmHg. Effluent pressure showed a progressive increase in the negative pressure applied to achieve ultrafiltration from 0 mmHg to -168 mmHg. The inflection point for such changes was also identified. Blood pathway pressures for access and return remained unchanged throughout. Automated electronic monitoring of circuit pressure during CRRT is possible and provides useful information on the evolution of circuit clotting.

Effect of high-pressure homogenization on droplet size distribution and rheological properties of ice cream mixes.

PubMed

Innocente, N; Biasutti, M; Venir, E; Spaziani, M; Marchesini, G

2009-05-01

The effect of different homogenization pressures (15/3 MPa and 97/3 MPa) on fat globule size and distribution as well as on structure-property relationships of ice cream mixes was investigated. Dynamic light scattering, steady shear, and dynamic rheological analyses were performed on mixes with different fat contents (5 and 8%) and different aging times (4 and 20 h). The homogenization of ice cream mixes determined a change from bimodal to monomodal particle size distributions and a reduction in the mean particle diameter. Mean fat globule diameters were reduced at higher pressure, but the homogenization effect on size reduction was less marked with the highest fat content. The rheological behavior of mixes was influenced by both the dispersed and the continuous phases. Higher fat contents caused greater viscosity and dynamic moduli. The lower homogenization pressure (15/3 MPa) mainly affected the dispersed phase and resulted in a more pronounced viscosity reduction in the higher fat content mixes. High-pressure homogenization (97/3 MPa) greatly enhanced the viscoelastic properties and the apparent viscosity. Rheological results indicated that unhomogenized and 15/3 MPa homogenized mixes behaved as weak gels. The 97/3 MPa treatment led to stronger gels, perhaps as the overall result of a network rearrangement or interpenetrating network formation, and the fat globules were found to behave as interactive fillers. High-pressure homogenization determined the apparent viscosity of 5% fat to be comparable to that of 8% fat unhomogenized mix.

Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In Vitro Model.

PubMed

Shehab, Sajad; Allida, Sabine M; Davidson, Patricia M; Newton, Phillip J; Robson, Desiree; Jansz, Paul C; Hayward, Christopher S

Right ventricular failure after left ventricular assist device (LVAD) implantation is associated with high mortality. Management remains limited to pharmacologic therapy and temporary mechanical support. Delayed right ventricular assist device (RVAD) support after LVAD implantation is associated with poorer outcomes. With the advent of miniaturized, durable, continuous flow ventricular assist device systems, chronic RVAD and biventricular assist device (BiVAD) support has been used with some success. The purpose of this study was to assess combined BiVAD and LVAD with delayed RVAD support within a four-elemental mock circulatory loop (MCL) simulating the human cardiovascular system. Our hypothesis was that delayed continuous flow RVAD (RVAD) would produce similar hemodynamic and flow parameters to those of initial BiVAD support. Using the MCL, baseline biventricular heart failure with elevated right and left filling pressures with low cardiac output was simulated. The addition of LVAD within a biventricular configuration improved cardiac output somewhat, but was associated with persistent right heart failure with elevated right-sided filling pressures. The addition of an RVAD significantly improved LVAD outputs and returned filling pressures to normal throughout the circulation. In conclusion, RVAD support successfully restored hemodynamics and flow parameters of biventricular failure supported with isolated LVAD with persistent elevated right atrial pressure.

Blood Pressure Associates with Standing Balance in Elderly Outpatients

PubMed Central

Pasma, Jantsje H.; Bijlsma, Astrid Y.; Klip, Janneke M.; Stijntjes, Marjon; Blauw, Gerard Jan; Muller, Majon; Meskers, Carel G. M.; Maier, Andrea B.

2014-01-01

Objectives Assessment of the association of blood pressure measurements in supine and standing position after a postural change, as a proxy for blood pressure regulation, with standing balance in a clinically relevant cohort of elderly, is of special interest as blood pressure may be important to identify patients at risk of having impaired standing balance in routine geriatric assessment. Materials and Methods In a cross-sectional cohort study, 197 community-dwelling elderly referred to a geriatric outpatient clinic of a middle-sized teaching hospital were included. Blood pressure was measured intermittently (n = 197) and continuously (subsample, n = 58) before and after a controlled postural change from supine to standing position. The ability to maintain standing balance was assessed during ten seconds of side-by-side, semi-tandem and tandem stance, with both eyes open and eyes closed. Self-reported impaired standing balance and history of falls were recorded by questionnaires. Logistic regression analyses were used to examine the association between blood pressure and 1) the ability to maintain standing balance; 2) self-reported impaired standing balance; and 3) history of falls, adjusted for age and sex. Results Blood pressure decrease after postural change, measured continuously, was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed and with increased self-reported impaired standing balance and falls. Presence of orthostatic hypotension was associated with reduced ability to maintain standing balance in semi-tandem stance with eyes closed for both intermittent and continuous measurements and with increased self-reported impaired standing balance for continuous measurements. Conclusion Continuous blood pressure measurements are of additional value to identify patients at risk of having impaired standing balance and may therefore be useful in routine geriatric care. PMID:25222275

Magic from Human Regenerative Technologies--Stem Cells

ERIC Educational Resources Information Center

Ritz, John M.

2012-01-01

Many people suffer from chronic diseases and problems due to injury from accidents or ailments. Some problems, such as measles and cancer, can be cured or put into remission with time, medicine, or treatments. Other ailments, such as high blood pressure, failing kidneys, and cystic fibrosis, cannot be cured and require continuous use of…

46 CFR 193.15-1 - Application.

Code of Federal Regulations, 2011 CFR

2011-10-01

... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 193.15-1 Application. (a) The provisions of this... this subpart are based on a “high pressure system,” i.e., one in which the carbon dioxide is stored in... carbon dioxide is stored in liquid form at a continuously controlled low temperature, may be specifically...

46 CFR 193.15-1 - Application.

Code of Federal Regulations, 2012 CFR

2012-10-01

... EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-1 Application. (a) The... requirements of this subpart are based on a “high pressure system,” i.e., one in which the carbon dioxide is... which the carbon dioxide is stored in liquid form at a continuously controlled low temperature, may be...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2012 CFR

2012-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2013 CFR

2013-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2014 CFR

2014-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

Special Education Professional Standards: How Important Are They in the Context of Teacher Performance Evaluation?

ERIC Educational Resources Information Center

Woolf, Sara B.

2015-01-01

Teacher performance evaluation represents a high stakes issue as evidenced by its pivotal emphasis in national and local education reform initiatives and federal policy levers. National, state, and local education leaders continue to experience unprecedented pressure to adopt standardized benchmarks to reflect and link student achievement data to…

Using Educational Technology to Help Students Get Back on Track

ERIC Educational Resources Information Center

Bertrand, Clare

2013-01-01

Increasingly, school districts, schools, and their partners are incorporating technology into strategies that help engage young people who have fallen off track to on-time graduation get back on track and move into effective educational pathways. This is especially true in light of the continuing pressure to raise high school graduation rates and…

Selection for Resistance to Imidacloprid in the House Fly (Diptera: Muscidae)

USDA-ARS?s Scientific Manuscript database

House flies, Musca domestica L., continue to be a primary pest of livestock facilities worldwide. This pest also has shown a propensity for pesticide resistance development when under high selection pressures. In this study a house fly strain, FDm was created by a 20% contribution from each of fiv...

Noninvasive intracranial pressure measurement using infrasonic emissions from the tympanic membrane.

PubMed

Stettin, Eduard; Paulat, Klaus; Schulz, Chris; Kunz, Ulrich; Mauer, Uwe Max

2011-06-01

We investigated whether ICP can be assessed by measuring infrasonic emissions from the tympanic membrane. An increase in ICP was induced in 22 patients with implanted ICP pressure sensors. ICP waveforms that were obtained invasively and continuously were compared with infrasonic emission waveforms. In addition, the noninvasive method was used in a control group of 14 healthy subjects. In a total of 83 measurements, the changes in ICP that were observed in response to different types of stimulation were detected in the waveforms obtained noninvasively as well as in those acquired invasively. Low ICP was associated with an initial high peak and further peaks with smaller amplitudes. High ICP was associated with a marked decrease in the number of peaks and in the difference between the amplitudes of the initial and last peaks. The assessment of infrasonic emissions, however, does not yet enable us to provide exact figures. It is conceivable that the assessment of infrasonic emissions will become suitable both as a screening tool and for the continuous monitoring of ICP in an intensive care environment.

Upcoming Methods and Specifications of Continuous Intraocular Pressure Monitoring Systems for Glaucoma

PubMed Central

Molaei, Amir; Karamzadeh, Vahid; Safi, Sare; Esfandiari, Hamed; Dargahi, Javad; Khosravi, Mohammad Azam

2018-01-01

Glaucoma is the leading cause of irreversible blindness and vision loss in the world. Although intraocular pressure (IOP) is no longer considered the only risk factor for glaucoma, it is still the most important one. In most cases, high IOP is secondary to trabecular meshwork dysfunction. High IOP leads to compaction of the lamina cribrosa and subsequent damage to retinal ganglion cell axons. Damage to the optic nerve head is evident on funduscopy as posterior bowing of the lamina cribrosa and increased cupping. Currently, the only documented method to slow or halt the progression of this disease is to decrease the IOP; hence, accurate IOP measurement is crucial not only for diagnosis, but also for the management. Due to the dynamic nature and fluctuation of the IOP, a single clinical measurement is not a reliable indicator of diurnal IOP; it requires 24-hour monitoring methods. Technological advances in microelectromechanical systems and microfluidics provide a promising solution for the effective measurement of IOP. This paper provides a broad overview of the upcoming technologies to be used for continuous IOP monitoring. PMID:29403593

High Pressure Electrolyzer System Evaluation

NASA Technical Reports Server (NTRS)

Prokopius, Kevin; Coloza, Anthony

2010-01-01

This report documents the continuing efforts to evaluate the operational state of a high pressure PEM based electrolyzer located at the NASA Glenn Research Center. This electrolyzer is a prototype system built by General Electric and refurbished by Hamilton Standard (now named Hamilton Sunstrand). It is capable of producing hydrogen and oxygen at an output pressure of 3000 psi. The electrolyzer has been in storage for a number of years. Evaluation and testing was performed to determine the state of the electrolyzer and provide an estimate of the cost for refurbishment. Pressure testing was performed using nitrogen gas through the oxygen ports to ascertain the status of the internal membranes and seals. It was determined that the integrity of the electrolyzer stack was good as there were no appreciable leaks in the membranes or seals within the stack. In addition to the integrity testing, an itemized list and part cost estimate was produced for the components of the electrolyzer system. An evaluation of the system s present state and an estimate of the cost to bring it back to operational status was also produced.

Deformation of Cases in High Capacitance Value Wet Tantalum Capacitors under Environmental Stresses

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2016-01-01

Internal gas pressure in hermetic wet tantalum capacitors is created by air, electrolyte vapor, and gas generated by electrochemical reactions at the electrodes. This pressure increases substantially with temperature and time of operation due to excessive leakage currents. Deformation of the case occurs when the internal pressure exceeds pressure of the environments and can raise significantly when a part operates in space. Contrary to the cylinder case wet tantalum capacitors that have external sealing by welding and internal sealing provided by the Teflon bushing and crimping of the case, no reliable internal sealing exists in the button case capacitors. Single seal design capacitors are used for high capacitance value wet tantalum capacitors manufactured per DLA L&M drawings #04003, 04005, and 10011, and require additional analysis to assure their reliable application in space systems. In this work, leakage currents and case deformation of button case capacitors were measured during different environmental test conditions. Recommendations for derating, screening and qualification testing are given. This work is a continuation of a series of NEPP reports related to quality and reliability of wet tantalum capacitors.

Electromagnetic Pumps for Conductive-Propellant Feed Systems

NASA Technical Reports Server (NTRS)

Markusic, Thomas E.; Polzin, Kurt A.; Dehoyos, Amado

2005-01-01

Prototype electromagnetic pumps for use with lithium and bismuth propellants were constructed and tested. Such pumps may be used to pressurize future electric propulsion liquid metal feed systems, with the primary advantages being the compactness and simplicity versus alternative pressurization technologies. Design details for two different pumps are described: the first was designed to withstand (highly corrosive) lithium propellant, and t he second was designed to tolerate the high temperature required to pump liquid bismuth. Both qualitative and quantitative test results are presented. Open-loop tests demonstrated the capability of each device to electromagnetically pump its design propellant (lithium or bismuth). A second set of tests accurately quantified the pump pressure developed as a function of current. These experiments, which utilized a more easily handled material (gallium), demonstrated continuously-adjustable pump pressure levels ranging from 0-100 Torr for corresponding input current levels of 0-75 A. While the analysis and testing in this study specifically targeted lithium and bismuth propellants, the underlying design principles should be useful in implementing liquid metal pumps in any conductive-propellant feed system.

Orbital dynamics of high area-to-mass ratio spacecraft with J2 and solar radiation pressure for novel Earth observation and communication services

NASA Astrophysics Data System (ADS)

Colombo, Camilla; Lücking, Charlotte; McInnes, Colin R.

2012-12-01

This paper investigates the effect of planetary oblateness and solar radiation pressure on the orbits of high area-to-mass spacecraft. A planar Hamiltonian model shows the existence of equilibrium orbits with the orbit apogee pointing towards or away from the Sun. These solutions are numerically continued to non-zero inclinations and considering the obliquity of the ecliptic plane relative to the equator. Quasi-frozen orbits are identified in eccentricity, inclination and the angle between the Sun-line and the orbit perigee. The long-term evolution of these orbits is then verified through numerical integration. A set of 'heliotropic' orbits with apogee pointing in the direction of the Sun is proposed for enhancing imaging and telecommunication on the day side of the Earth. The effects of J2 and solar radiation pressure are exploited to obtain a passive rotation of the apsides line following the Sun; moreover the effect of solar radiation pressure enables such orbits at higher eccentricities with respect to the J2 only case.

Real-time Continuous Esophageal High-resolution Manometry (HRM) During Laparoscopic Heller Myotomy and Dor Fundoplication for the Treatment of Achalasia. A Promising Novelty in Regards of Perfecting Surgical Technique: Could It Guide Surgical Technique Toward Excellent Results?

PubMed

Triantafyllou, Tania; Doulami, Georgia; Papailiou, Joanna; Mantides, Apostolos; Zografos, Georgios; Theodorou, Dimitrios

2016-12-01

High-resolution manometry (HRM) is the gold-standard diagnostic tool for achalasia of the esophagus. Laparoscopic Heller-Dor technique is the preferred surgical approach with success rate estimated 90%. The use of intraoperative HRM provides real-time estimation of intraluminal esophageal pressures and identifies the exact points of esophageal luminal pressure during laparoscopy. Ten patients with achalasia underwent surgery. All patients preoperatively completed 1 manometric study and Quality of Life questionnaires (EORTC QLQ-C30 version 3.0) with Eckardt scores. We collected intraoperative manometry data and repeated manometric studies, EORTC QLQ-C30, and Eckardt scores postoperatively. Median Eckardt score was decreased from 7.5 to 0.5, mean resting pressure decreased from 51.4 to 11.9 mm Hg, whereas mean residual pressure diminished from 45.9 to 9.5 mm Hg postoperatively. The simultaneous use of HRM during the Heller-Dor technique may lead to an individualized management of the disease.

Flexible Composite-Material Pressure Vessel

NASA Technical Reports Server (NTRS)

Brown, Glen; Haggard, Roy; Harris, Paul A.

2003-01-01

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

Wall relaxation in growing stems: comparison of four species and assessment of measurement techniques

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.

1987-01-01

This study was carried out to develop improved methods for measuring in-vivo stress relaxation of growing tissues and to compare relaxation in the stems of four different species. When water uptake by growing tissue is prevented, in-vivo stress relaxation occurs because continued wall loosening reduces wall stress and cell turgor pressure. With this procedure one may measure the yield threshold for growth (Y), the turgor pressure in excess of the yield threshold (P-Y), and the physiological wall extensibility (phi). Three relaxation techniques proved useful: "turgor-relaxation", "balance-pressure" and "pressure-block". In the turgor-relaxation method, water is withheld from growing tissue and the reduction in turgor is measured directly with the pressure probe. This technique gives absolute values for P and Y, but requires tissue excision. In the balance-pressure technique, the excised growing region is sealed in a pressure chamber, and the subsequent reduction in water potential is measured as the applied pressure needed to return xylem sap to the cut surface. This method is simple, but only measures (P-Y), not the individual values of P and Y. In the pressure-block technique, the growing tissue is sealed into a pressure chamber, growth is monitored continuously, and just sufficient pressure is applied to the chamber to block growth. The method gives high-resolution kinetics of relaxation and does not require tissue excision, but only measures (P-Y). The three methods gave similar results when applied to the growing stems of pea (Pisum sativum L.), cucumber (Cucumis sativus L.), soybean (Glycine max (L.) Merr.) and zucchini (Curcubita pepo L.) seedlings. Values for (P-Y) averaged between 1.4 and 2.7 bar, depending on species. Yield thresholds averaged between 1.3 and 3.0 bar. Compared with the other methods, relaxation by pressure-block was faster and exhibited dynamic changes in wall-yielding properties. The two pressure-chamber methods were also used to measure the internal water-potential gradient (between the xylem and the epidermis) which drives water uptake for growth. For the four species it was small, between 0.3 and 0.6 bar, and so did not limit growth substantially.

The investigation of degradation reaction of various saccharides in high temperature and high pressure water

NASA Astrophysics Data System (ADS)

Saito, T.; Noguchi, S.; Matsumoto, T.; Sasaki, M.; Goto, M.

2008-07-01

Recently, conversions of polysaccharides included in biomass resources have been studied in order to recover valuable chemicals. Degradation of polysaccharides has been attracted by many researchers, whereas by-products from secondary reactions of the materials have not been studied very well. For the purpose of understanding reaction behavior of various monosaccharides in high-temperature and high-pressure water regions, we investigated reaction pathway and kinetics through reaction experiments of degradation of saccharides in subcritical water. The experiment was conducted by using continuous flow-type micro-reactors. Glucose was used as the starting material. From the experimental results, the conversion of glucose increased with increasing the residence time. The yields of fructose and 1, 6-anhydro-β-D-glucose decreased with increasing the residence time. The yields of organic acids and some aldehydes increased with increasing the residence time.

History of Japan-U.S./High Pressure Mineral Physics Seminars: 1976 to 2012

NASA Astrophysics Data System (ADS)

Liebermann, Robert Cooper

2014-03-01

Under the auspices of the U.S.-Japan Cooperative Science Program between the U.S. National Science Foundation and the Japan Society for the Promotion of Science, the first U.S.-Japan joint seminar on High Pressure Research Applications in Geophysics was held in Honolulu, Hawaii, 5-8 July 1976 and was attended by 47 scientists. Originated as bilateral U.S.-Japan seminars on high-pressure research applications in geophysics by Murli Manghnani and Syun-iti Akimoto, this series continued at 5-year intervals under those auspices from 1976 to 1996 [1981 in Hakone, Japan 1986 in Turtle Bay, Hawaii, 1991 in Ise, Japan, and 1996 in Maui, Hawaii], with venues alternating between Hawaii and Japan. In the 21st century, as a result of growing international interest in high-pressure mineral physics, the seminar series was re-envisioned with a broader focus “more international” focus than the original U.S.-Japan bilateral series. The first of the new meetings entitled “High Pressure Mineral Physics Seminars” [HPMP-6] took place in Verbania, Italy on August 26-31, 2002. More than 84 scientists from Asia, Australia, the Americas and Europe attended. HPMPS-7 took place in Matsushima, Japan on May 8-12, 2007 and was attended by 134 scientists from throughout the world. In this paper, we review this history culminating with the HPMPS-8 at Lake Tahoe, California in July 2012, which was held jointly with the Annual Meeting of COMPRES: Consortium for Materials Properties Research in Earth Sciences.

Long-Term Reduction of High Blood Pressure by Angiotensin II DNA Vaccine in Spontaneously Hypertensive Rats.

PubMed

Koriyama, Hiroshi; Nakagami, Hironori; Nakagami, Futoshi; Osako, Mariana Kiomy; Kyutoku, Mariko; Shimamura, Munehisa; Kurinami, Hitomi; Katsuya, Tomohiro; Rakugi, Hiromi; Morishita, Ryuichi

2015-07-01

Recent research on vaccination has extended its scope from infectious diseases to chronic diseases, including Alzheimer disease, dyslipidemia, and hypertension. The aim of this study was to design DNA vaccines for high blood pressure and eventually develop human vaccine therapy to treat hypertension. Plasmid vector encoding hepatitis B core-angiotensin II (Ang II) fusion protein was injected into spontaneously hypertensive rats using needleless injection system. Anti-Ang II antibody was successfully produced in hepatitis B core-Ang II group, and antibody response against Ang II was sustained for at least 6 months. Systolic blood pressure was consistently lower in hepatitis B core-Ang II group after immunization, whereas blood pressure reduction was continued for at least 6 months. Perivascular fibrosis in heart tissue was also significantly decreased in hepatitis B core-Ang II group. Survival rate was significantly improved in hepatitis B core-Ang II group. This study demonstrated that Ang II DNA vaccine to spontaneously hypertensive rats significantly lowered high blood pressure for at least 6 months. In addition, Ang II DNA vaccines induced an adequate humoral immune response while avoiding the activation of self-reactive T cells, assessed by ELISPOT assay. Future development of DNA vaccine to treat hypertension may provide a new therapeutic option to treat hypertension. © 2015 American Heart Association, Inc.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Continuous Positive Airway Pressure Strategies with Bubble Nasal Continuous Positive Airway Pressure: Not All Bubbling Is the Same: The Seattle Positive Airway Pressure System.

PubMed

Welty, Stephen E

2016-12-01

Premature neonates are predisposed to complications, including bronchopulmonary dysplasia (BPD). BPD is associated with long-term pulmonary and neurodevelopmental consequences. Noninvasive respiratory support with nasal continuous positive airway pressure (CPAP) has been recommended strongly by the American Academy of Pediatrics. However, CPAP implementation has shown at least a 50% failure rate. Enhancing nasal CPAP effectiveness may decrease the need for mechanical ventilation and reduce the incidence of BPD. Bubble nasal CPAP is better than nasal CPAP using mechanical devices and the bubbling provides air exchange in distal respiratory units. The Seattle PAP system reduces parameters that assess work of breathing. Copyright © 2016 Elsevier Inc. All rights reserved.

Refining the Use of Nasal High-Flow Therapy as Primary Respiratory Support for Preterm Infants.

PubMed

Manley, Brett J; Roberts, Calum T; Frøisland, Dag H; Doyle, Lex W; Davis, Peter G; Owen, Louise S

2018-05-01

To identify clinical and demographic variables that predict nasal high-flow (nHF) treatment failure when used as a primary respiratory support for preterm infants. This secondary analysis used data from a multicenter, randomized, controlled trial comparing nHF with continuous positive airway pressure as primary respiratory support in preterm infants 28-36 completed weeks of gestation. Treatment success or failure with nHF was determined using treatment failure criteria within the first 72 hours after randomization. Infants in whom nHF treatment failed received continuous positive airway pressure, and were then intubated if failure criteria were again met. There were 278 preterm infants included, with a mean gestational age (GA) of 32.0 ± 2.1 weeks and a birth weight of 1737 ± 580 g; of these, nHF treatment failed in 71 infants (25.5%). Treatment failure was moderately predicted by a lower GA and higher prerandomization fraction of inspired oxygen (FiO 2 ): area under a receiver operating characteristic curve of 0.76 (95% CI, 0.70-0.83). Nasal HF treatment success was more likely in infants born at ≥30 weeks GA and with prerandomization FiO 2 <0.30. In preterm infants ≥28 weeks' GA enrolled in a randomized, controlled trial, lower GA and higher FiO 2 before randomization predicted early nHF treatment failure. Infants were more likely to be successfully treated with nHF from soon after birth if they were born at ≥30 weeks GA and had a prerandomization FiO 2 <0.30. However, even in this select population, continuous positive airway pressure remains superior to nHF as early respiratory support in preventing treatment failure. Australian New Zealand Clinical Trials Registry: ACTRN12613000303741. Copyright © 2018 Elsevier Inc. All rights reserved.

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

49 CFR 195.304 - Test pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Test pressure. 195.304 Section 195.304... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under...

Understanding the use of continuous oscillating positive airway pressure (bubble CPAP) to treat neonatal respiratory disease: an engineering approach.

PubMed

Manilal-Reddy, P I; Al-Jumaily, A M

2009-01-01

A continuous oscillatory positive airway pressure with pressure oscillations incidental to the mean airway pressure (bubble CPAP) is defined as a modified form of traditional continuous positive airway pressure (CPAP) delivery where pressure oscillations in addition to CPAP are administered to neonates with lung diseases. The mechanical effect of the pressure oscillations on lung performance is investigated by formulating mathematical models of a typical bubble CPAP device and a simple representation of a neonatal respiratory system. Preliminary results of the respiratory system's mechanical response suggest that bubble CPAP may improve lung performance by minimizing the respiratory system impedance and that the resonant frequency of the respiratory system may be a controlling factor. Additional steps in terms of clinical trials and a more complex respiratory system model are required to gain a deeper insight into the mechanical receptiveness of the respiratory system to pressure oscillations. However, the current results are promising in that they offer a deeper insight into the trends of variations that can be expected in future extended models as well as the model philosophies that need to be adopted to produce results that are compatible with experimental verification.

[Experimental model for the examination of inner pressure tolerance of telescopic anastomosis and other frequently performed anastomosis types of the esophagus].

PubMed

Szúcs, G; Tóth, I; Bráth, E; Gyáni, K; Miko, I

2001-08-01

We have good results with telescopic anastomosis technique in partial oesophagectomies and gastrectomies. As we could not find data about the healing process of telescopic anastomoses so we started experimenting. Inside pressure tolerance was examined immediately after performing anastomoses by measuring the bursting pressure using the organs of pigs slaughtered in the meat industry. Both oesophago-gastrostomies and oesophago-jejunostomies were performed with telescopic, single layer interrupted, single layer continuous, double layer interrupted and double layer continuous-interrupted technique, 9 of each anastomosis. A series of oesophago-jejunostomies were performed with EEA stapler. 99 anastomoses of 11 types were investigated. We found, that the inner pressure tolerance of telescopic oesophago-gastrostomy is better than any other single layer type variant. On the other hand the double layer type variants have much better pressure tolerance than the telescopic and other two type single layer anastomoses. The difference is statistically significant. In oesophago-jejunostomies the pressure tolerance of telescopic anastomosis is better than of the single layer interrupted type but the difference between the telescopic and single layer continuous type anastomoses is not significant. The pressure tolerance of double layer anastomosis is higher than the telescopic one but the difference is significant only in the continuous-interrupted type. The inner pressure tolerance of telescopic and EEA stapler anastomoses are equal. The investigation of additional features in anastomosis healing is in progress.

Measurements of emission-propagation phenomena in low-energy atmospheric-pressure helium plasma

NASA Astrophysics Data System (ADS)

Yamada, Hiromasa; Shimizu, Tetsuji; Fujiwara, Masanori; Kato, Susumu; Fujiwara, Yutaka; Itagaki, Hirotomo; Kiyama, Satoru; Kim, Jaeho; Ikehara, Sanae; Shimizu, Nobuyuki; Nakanishi, Hayao; Ikehara, Yuzuru; Sakakita, Hajime

2018-05-01

In a low-temperature atmospheric pressure plasma jet using helium gas, emission-propagation phenomena, such as streamers and striations were measured using a high-speed intensified charge-coupled device camera. A particular focus was placed on the study of the dependence of the phenomena on the distance between the nozzle of the plasma device and a target plate. When the distance decreased, a transition from the positive streamer to a spatially continuous emission resulted. A further distance reduction resulted in a new propagation mode in which the positive and negative streamers appeared alternately with different current waveforms over two cycles of applied voltage. This phenomenon may be related to residual charges of the preceding cycle when streamer propagation begins. Striation structures were observed in the tail of the positive streamer head and in the successive spatially continuous-emission region. These structures can be measured only within a shorter period than one voltage cycle.

Renal effects of continuous negative pressure breathing

NASA Technical Reports Server (NTRS)

Kinney, M. J.; Discala, V. A.

1975-01-01

Continuous negative pressure breathing (CNPB) was utilized to simulate the thoracic vascular distension of zero g or space, in 11 anesthetized rats. The animals underwent renal clearance and micropuncture renal nephron studies before, during, and after CNPB. Rats were pretreated with a high salt diet and I-M desoxycorticosterone (DOCA) in excess. None of these rats diuresed with CNPB. In contrast 5 of the 7 remaining rats increased the fraction of the filtered sodium excreted (C sub Na/GFR, p .05) and their urinary flow rate (V, p .05). Potassium excretion increased (U sub k V, p .05). End proximal tubular fluid specimen's TF/P inulin ratios were unchanged. Whole kidney and single nephron glomerular filtration rates fell 10%. CNPB, a mechanism for atrial distension, appears to cause, in rats, a decrease in distal tubular sodium, water and potassium reabsorption. Exogenous mineral-corticoid prevents the diuresis, saluresis, and kaluresis.

Continuous positive airway pressure (CPAP) to treat respiratory distress in newborns in low- and middle-income countries.

PubMed

Dewez, Juan Emmanuel; van den Broek, Nynke

2017-01-01

Severe respiratory distress is a serious complication common to the three major causes of neonatal mortality and morbidity (prematurity, intra-partum-related hypoxia and infections). In low- and middle-income countries (LMICs), 20% of babies presenting with severe respiratory distress die.Continuous positive airway pressure (CPAP), is an effective intervention for respiratory distress in newborns and widely used in high-income countries. Following the development of simple, safe and relatively inexpensive CPAP devices, there is potential for large-scale implementation in the developing world.In this article, we describe existing CPAP systems and present a review of the current literature examining the effectiveness of CPAP compared to standard care (oxygen) in newborns with respiratory distress. We also discuss the evidence gap which needs to be addressed prior to its integration into health systems in LMICs. © The Author(s) 2016.

Continuous positive airway pressure (CPAP) to treat respiratory distress in newborns in low- and middle-income countries

PubMed Central

van den Broek, Nynke

2016-01-01

Severe respiratory distress is a serious complication common to the three major causes of neonatal mortality and morbidity (prematurity, intra-partum-related hypoxia and infections). In low- and middle-income countries (LMICs), 20% of babies presenting with severe respiratory distress die. Continuous positive airway pressure (CPAP), is an effective intervention for respiratory distress in newborns and widely used in high-income countries. Following the development of simple, safe and relatively inexpensive CPAP devices, there is potential for large-scale implementation in the developing world. In this article, we describe existing CPAP systems and present a review of the current literature examining the effectiveness of CPAP compared to standard care (oxygen) in newborns with respiratory distress. We also discuss the evidence gap which needs to be addressed prior to its integration into health systems in LMICs. PMID:26864235

The Effect of Low Volume Interval Training on Resting Blood Pressure in Pre-hypertensive Subjects: A Preliminary Study.

PubMed

Skutnik, Benjamin C; Smith, Joshua R; Johnson, Ariel M; Kurti, Stephanie P; Harms, Craig A

2016-01-01

Clinically pre-hypertensive adults are at a greater risk of developing hypertension, stiffened arteries, and other cardiovascular risks. Endurance exercise training has been shown to improve elevated resting blood pressure and C-reactive protein (CRP) levels. However, a primary barrier preventing individuals from engaging in regular physical activity is a lack of time. The purpose of our study was to determine if a high-intensity interval training (HIIT) protocol would be as effective as continuous aerobic endurance training (ET) on resting blood pressure in pre-hypertensive participants. Additionally, this study investigated the effects of HIIT vs. ET on CRP. Twelve pre-hypertensive participants (33.3±6.1 yrs; 3M/9W) participated in 8 weeks of cycle ergometer exercise training. The ET exercised for 30 continuous min/day, 4 days/week at 40% VO2max reserve. The HIIT exercised at a 1:1 work-to-rest for 20 min/day, 3 days/week at 60% peak power. Resting mean arterial pressure and CRP were compared throughout the study. Both groups showed decreases (p<0.001) in mean arterial pressure (ET: -11.5 ± 5.9 mmHg; HIIT: -8.6 ± 4.8 mmHg) following the 8 weeks. For CRP, there was a significant decrease (p=0.014) as a main effect of time. VO2max increased (p<0.001) approximately 25% for both HIIT and ET. These preliminary data suggest HIIT and ET similarly decreased resting blood pressure and increased VO2max.

Stress-Corrosion Cracking in High Strength Steels and in Titanium and Aluminum Alloys

DTIC Science & Technology

1972-01-01

EFFECTS 01: STRESS) 155 Table 2. Mechanical, Fracture, and Stress Corrosion Properties for Plates of Several Aluminum Alloys --Continued 4f’l14...One of the most effective SCC preventives for high strength aluminum alloys is surface working by shot peening, particularl) when used in combination...Aluminaut uses aluminum alloy anodes to supplement the protection of the pressure hull offered by several layers of polyurethane coating 175). 100 A

Progress in the Production of JP-8 Based Hydrogen and Advanced Tactical Fuels for Military Applications

DTIC Science & Technology

2011-02-01

of a multi- year program to develop, optimize, and demonstrate the military viability of a technology for on-demand production of high...continuous reactor system used for kinetic rate data experiment 86 52 Schematic of a differential reactor. The catalyst bed is kept small , and...program to develop, optimize, and demonstrate the military viability of a technology for on-demand production of high-pressure hydrogen for fuel

Noninvasive continuous blood pressure monitoring by the ClearSight system during robot-assisted laparoscopic radical prostatectomy.

PubMed

Sakai, Yoko; Yasuo M, Tsutsumi; Oyama, Takuro; Murakami, Chiaki; Kakuta, Nami; Tanaka, Katsuya

2018-01-01

Robot-assisted laparoscopic radical prostatectomy (RALRP) is commonly performed in the surgical treatment of prostate cancer. However, the steep Trendelenburg position (25) and pneumoperitoneum required for this procedure can sometimes cause hemodynamic changes. Although blood pressure is traditionally monitored invasively during RALRP, the ClearSight system (BMEYE, Amsterdam, The Netherlands) enables a totally noninvasive and simple continuous blood pressure and cardiac output monitoring based on finger arterial pressure pulse contour analysis. We therefore investigated whether noninvasive continuous arterial blood pressure measurements using the ClearSight system were comparable to those obtained invasively in patients undergoing RALRP. Ten patients scheduled for RALRP with American Society of Anesthesiologists physical status I-II were included in this study. At each of the seven defined time points, noninvasive and invasive blood pressure measurements were documented and compared in each patient using Bland-Altman analysis. Although the blood pressure measured with the ClearSight system correlated with that measured invasively, a large difference between the values obtained by the two devices was noted. The ClearSight system was unable to detect blood pressure accurately during RALRP, suggesting that blood pressure monitoring using this device alone is not feasible in this small patient population. J. Med. Invest. 65:69-73, February, 2018.

An ultra-high vacuum chamber for scattering experiments featuring in-vacuum continuous in-plane variation of the angle between entrance and exit vacuum ports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Englund, Carl-Johan; Agåker, Marcus, E-mail: marcus.agaker@physics.uu.se; Fredriksson, Pierre

2015-09-15

A concept that enables in-vacuum continuous variation of the angle between two ports in one plane has been developed and implemented. The vacuum chamber allows for measuring scattering cross sections as a function of scattering angle and is intended for resonant inelastic X-ray scattering experiments. The angle between the ports can be varied in the range of 30°-150°, while the pressure change is less than 2 × 10{sup −10} mbars.

High Pressure Optical Studies of the Thallous Halides and of Charge-Transfer Complexes

NASA Astrophysics Data System (ADS)

Jurgensen, Charles Willard

High pressure was used to study the insulator -to-metal transition in sulfur and the thallous halides and to study the intermolecular interactions in charge -transfer complexes. The approach to the band overlap insulator -to-metal transition was studied in three thallous halides and sulfur by optical absorption measurements of the band gap as a function of pressure. The band gap of sulfur continuously decreases with pressure up to the insulator -to-metal transition which occurs between 450 and 485 kbars. The results on the thallous halides indicate that the indirect gap decreases more rapidly than the direct gap; the closing of the indirect gap is responsible for the observed insulator -to-metal transitions. High pressure electronic and vibrational spectroscopic measurements on the solid-state complexes of HMB-TCNE were used to study the intermolecular interactions of charge -transfer complexes. The vibrational frequency shifts indicate that the degree of charge transfer increases with pressure which is independently confirmed by an increase in the molar absorptivity of the electronic charge-transfer peak. Induction and dispersion forces contribute towards a red shift of the charge-transfer peak; however, charge-transfer resonance contributes toward a blue shift and this effect is dominant for the HMB-TCNE complexes. High pressure electronic spectra were used to study the effect of intermolecular interactions on the electronic states of TCNQ and its complexes. The red shifts with pressure of the electronic spectra of TCNQ and (TCNQ)(' -) in polymer media and of crystalline TCNQ can be understood in terms of Van der Waals interactions. None of the calculations which considered intradimer distance obtained the proper behavior for either the charge-transfer of the locally excited states of the complexes. The qualitative behavior of both states can be interpreted as the effect of increased mixing of the locally excited and charge transfer states.

Expansion of high-temperature; high-pressure data set for coal gasification: Sixth quarterly report, December 28, 1985-March 28, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.

1986-01-01

During the sixth quarter, work was completed on modifications of the high pressure reactor (HPR) system for higher pressure (600 psig) operation. A series of pyrolysis experiments was completed in the HPR using mixtures of nitrogen and oxygen at various pressures and compositions. The original intention of the O/sub 2//N/sub 2/ experiments was to examine the effects of oxygen on the pyrolysis product distribution and the char reactivity. Unfortunately, at the temperature, residence time and pressure used for most of the experiments in this series (817/sup 0/C, 0.47 s, 26 psig) nearly complete oxidation of the char and volatile productsmore » occurred. Additional CO/sub 2/ gasification experiments were done to provide a database for revising the test plan. These were done at a variety of temperatures, pressures and CO/sub 2/ concentrations. The reactor was then switched back to nitrogen and additional pyrolysis experiments were done at high pressure (300 psig). When it was observed that the material balance was falling off slightly, it was decided to repeat some of the previous pyrolysis experiments at low pressure. There appeared to be a small, but systematic, reduction in char recovery. We continued to do char reactivity and surface area measurements for chars using the new non-isothermal technique described in the Fifth Quarterly report. A comparison was made of the results for char, tar, and gas yields for 1 atm and 5 atm (60 psig) experiments in the HTR. The asymptotic yield of about 10% was similar for both sets of experiments. A comparison was also made of tar yields for the Montana Rosebud coal from experiments in the HPR and HTR. The observed tar yields were in good agreement for similar experimental conditions. A preliminary version of a particle temperature model for the HPR was completed during the past quarter. 9 refs., 2 figs., 3 tabs.« less

Do Arthroscopic Fluid Pumps Display True Surgical Site Pressure During Hip Arthroscopy?

PubMed

Ross, Jeremy A; Marland, Jennifer D; Payne, Brayden; Whiting, Daniel R; West, Hugh S

2018-01-01

To report on the accuracy of 5 commercially available arthroscopic fluid pumps to measure fluid pressure at the surgical site during hip arthroscopy. Patients undergoing hip arthroscopy for femoroacetabular impingement were block randomized to the use of 1 of 5 arthroscopic fluid pumps. A spinal needle inserted into the operative field was used to measure surgical site pressure. Displayed pump pressures and surgical site pressures were recorded at 30-second intervals for the duration of the case. Mean differences between displayed pump pressures and surgical site pressures were obtained for each pump group. Of the 5 pumps studied, 3 (Crossflow, 24K, and Continuous Wave III) reflected the operative field fluid pressure within 11 mm Hg of the pressure readout. In contrast, 2 of the 5 pumps (Double Pump RF and FMS/DUO+) showed a difference of greater than 59 mm Hg between the operative field fluid pressure and the pressure readout. Joint-calibrated pumps more closely reflect true surgical site pressure than gravity-equivalent pumps. With a basic understanding of pump design, either type of pump can be used safely and efficiently. The risk of unfamiliarity with these differences is, on one end, the possibility of pump underperformance and, on the other, potentially dangerously high operating pressures. Level II, prospective block-randomized study. Copyright © 2017. Published by Elsevier Inc.

Pulsed pressure treatment for inactivation of escherichia coli and listeria innocua in whole milk

NASA Astrophysics Data System (ADS)

Buzrul, S.; Largeteau, A.; Alpas, H.; Demazeau, G.

2008-07-01

E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min × 2 pulses, 1 min × 5 pulses and 0.5 min × 10 pulses), 10 min (5 min × 2 pulses, 2 min × 5 pulses and 1 min × 10 pulses), 15 min (5 min × 3 pulses, 3 min × 5 pulses and 1.5 min × 10 pulses) and 20 min (10 min × 2 pulses, 5 min × 4 pulses, 4 min × 5 pulses and 2 min × 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms.

Pretreatment process for forming a smooth surface diamond film on a carbon-coated substrate

DOEpatents

Feng, Zhu; Brewer, Marilee; Brown, Ian; Komvopoulos, Kyriakos

1994-01-01

A process is disclosed for the pretreatment of a carbon-coated substrate to provide a uniform high density of nucleation sites thereon for the subsequent deposition of a continuous diamond film without the application of a bias voltage to the substrate. The process comprises exposing the carbon-coated substrate, in a microwave plasma enhanced chemical vapor deposition system, to a mixture of hydrogen-methane gases, having a methane gas concentration of at least about 4% (as measured by partial pressure), while maintaining the substrate at a pressure of about 10 to about 30 Torr during the pretreatment.

Phase behavior of metastable liquid silicon at negative pressure: Ab initio molecular dynamics

NASA Astrophysics Data System (ADS)

Zhao, G.; Yu, Y. J.; Yan, J. L.; Ding, M. C.; Zhao, X. G.; Wang, H. Y.

2016-04-01

Extensive first-principle molecular dynamics simulations are performed to study the phase behavior of metastable liquid Si at negative pressure. Our results show that the high-density liquid (HDL) and HDL-vapor spinodals indeed form a continuous reentrant curve and the liquid-liquid critical point seems to just coincide with its minimum. The line of density maxima also has a strong tendency to pass through this minimum. The phase behaviour of metastable liquid Si therefore tends to be a critical-point-free scenario rather than a second-critical-point one based on SW potential.

[A case of migraine presenting with thunderclap headache associated with posterior reversible encephalopathy syndrome].

PubMed

Katoh, Hirotaka; Saito, Yu; Ohwan, Yoshiyuki; Kasai, Hideyo; Fujita, Kazuhisa; Kawamura, Mitsuru

2014-10-01

We report a 47-year-old woman who developed a thunderclap headache. Head axial, fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI) revealed high signal lesions in the left occipital and right parietal lobes. Apparent diffusion coefficient mapping showed a vasogenic edema pattern. Upon admission, the patient's blood pressure was normal and the neurological examination was unremarkable. As thunderclap headaches are associated with a repeated rise in blood pressure, we considered cerebral vasoconstriction and administered a calcium channel blocker. Thereafter, her headache with high blood pressure eased significantly and the high signal lesions on FLAIR MRI disappeared. We diagnosed the condition as posterior reversible encephalopathy syndrome (PRES). In addition, head magnetic resonance angiogram showed vasoconstriction of the right anterior cerebral artery, left middle cerebral artery, and bilateral posterior cerebral artery. Calcium channel blocker use was continued and vasoconstriction improved by day 70. In this case, the presenting symptom was thunderclap headache, which is a characteristic feature of reversible cerebral vasoconstriction syndrome (RCVS). Therefore, PRES may be caused by RCVS.

High pressure inactivation of Clostridium botulinum type E endospores in model emulsion systems

NASA Astrophysics Data System (ADS)

Schnabel, Juliane; Lenz, Christian A.; Vogel, Rudi F.

2015-01-01

Clostridium botulinum type E is a cold-tolerant, neurotoxigenic, endospore-forming organism, primarily associated with aquatic environments. High pressure thermal (HPT) processing presents a promising tool to enhance food safety and stability. The effect of fat on HPT inactivation of C. botulinum type E spores was investigated using an emulsion model system. The distribution of spores in oil-in-water (O/W) emulsions and their HPT (300-750 MPa, 45-75 °C, 10 min) inactivation was determined as a function of emulsion fat content (30-70% (v/v) soybean oil in buffer). Approximately 26% and 74% of the spores were located at the oil-buffer interface and the continuous phase, respectively. Spore inactivation in emulsion systems decreased with increasing oil contents, which suggests that the fat content of food plays an important role in the protection of C. botulinum type E endospores against HPT treatments. These results can be helpful for future safety considerations. This paper was presented at the 8th International Conference on High Pressure Bioscience & Biotechnology (HPBB 2014), in Nantes (France), 15-18 July 2014.

MONITORING OF PORE WATER PRESSURE AND WATER CONTENT AROUND A HORIZONTAL DRIFT THROUGH EXCAVATION - MEASUREMENT AT THE 140m GALLERY IN THE HORONOBE URL -

NASA Astrophysics Data System (ADS)

Yabuuchi, Satoshi; Kunimaru, Takanori; Kishi, Atsuyasu; Komatsu, Mitsuru

Japan Atomic Energy Agency has been conducting the Horonobe Underground Research Laboratory (URL) project in Horonobe, Hokkaido, as a part of the research and development program on geological disposal of high-level radioactive waste. Pore water pressure and water content around a horizontal drift in the URL have been monitored for over 18 months since before the drift excavation was started. During the drift excavation, both pore water pressure and water content were decreasing. Pore water pressure has been still positive though it continued to decrease with its gradient gradually smaller after excavation, while water content turned to increase about 6 months after the completion of the excavation. It turned to fall again about 5 months later. An unsaturated zone containing gases which were dissolved in groundwater may have been formed around the horizontal drift.

Phase diagram of two-dimensional hard ellipses.

PubMed

Bautista-Carbajal, Gustavo; Odriozola, Gerardo

2014-05-28

We report the phase diagram of two-dimensional hard ellipses as obtained from replica exchange Monte Carlo simulations. The replica exchange is implemented by expanding the isobaric ensemble in pressure. The phase diagram shows four regions: isotropic, nematic, plastic, and solid (letting aside the hexatic phase at the isotropic-plastic two-step transition [E. P. Bernard and W. Krauth, Phys. Rev. Lett. 107, 155704 (2011)]). At low anisotropies, the isotropic fluid turns into a plastic phase which in turn yields a solid for increasing pressure (area fraction). Intermediate anisotropies lead to a single first order transition (isotropic-solid). Finally, large anisotropies yield an isotropic-nematic transition at low pressures and a high-pressure nematic-solid transition. We obtain continuous isotropic-nematic transitions. For the transitions involving quasi-long-range positional ordering, i.e., isotropic-plastic, isotropic-solid, and nematic-solid, we observe bimodal probability density functions. This supports first order transition scenarios.

Diastolic blood pressure-estimated left ventricular dp/dt.

PubMed

Yilmaz, Hüseyin; Minareci, Kenan; Kabukçu, Mehmet; Sancaktar, Oktay

2002-02-01

Peak dp/dt is one of the best isovolumic phase indexes of the myocardial contractile state requiring invasive procedures or presence of mitral regurgitation severe enough to measure in clinical practice by Doppler echocardiography. In this study, we sought the correlation between two noninvasive methods of measurements for left ventricular dp/dt-diastolic blood pressure- (DBP) estimated and continuous-wave Doppler-derived dp/dt-min electrocardiographic/echocardiographic study to emphasize the clinical feasibility of the DBP-estimated method. Thirty-six randomized patients (27 male, 9 female; 58 +/- 8 years) with mild mitral regurgitation were enrolled in this study. DBP-estimated dp/dt was calculated from DBP minus the left ventricular end-diastolic pressure (LVEDP) over the isovolumetric contraction time (IVCT). LVEDP was assumed to be 10 mmHg for all patients. Doppler-determined left ventricular dp/dt was derived from the continuous-wave Doppler spectrum of mitral regurgitation jet by dividing the magnitude of the left ventricular atrial pressure gradient rise between 1 mm/sec-3 mm/sec of mitral regurgitant velocity signal by the time taken for this change. Left ventricular dp/dt by Doppler was 1122 +/- 303 mmHg/sec and blood pressure-estimated dp/dt was 1063 +/- 294 mmHg/sec. There was a high correlation (r = 0.97, P < 0.001) of dp/dt between the two techniques. DBP and IVCT can generate left ventricular dp/dt without invasive procedures, even in the absence of mitral regurgitation in clinical practice.

Pressure-induced phase transitions of β-type pyrochlore CsTaWO 6

DOE PAGES

Zhang, F. X.; Tracy, C. L.; Shamblin, J.; ...

2016-09-30

The β-type pyrochlore CsTaWO 6 was studied by synchrotron X-ray diffraction (XRD) and Raman scattering methods up to pressures of 43 GPa using a diamond anvil cell (DAC). With increasing pressure, the cubic pyrochlore in space group of Fd-3¯m with combining macron]m transforms to an orthorhombic structure (space group: Pnma) at 5.9 GPa and then to a monoclinic structure (space group: P2 1/c) at ~18 GPa. The structural evolution in CsTaWO 6 is a continuous process and experimental results suggest that the initial cubic phase has a tetragonal distortion at ambient conditions. Both XRD and Raman measurements indicate that themore » pressure-induced phase transitions in CsTaWO 6 are reversible. Lastly, these results may provide a structural explanation of previous experimental resistivity measurement results for the isostructural superconductor K(Cs)Os 2O 6 at high pressure conditions.« less

Pressure-induced phase transitions of β-type pyrochlore CsTaWO 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, F. X.; Tracy, C. L.; Shamblin, J.

The β-type pyrochlore CsTaWO 6 was studied by synchrotron X-ray diffraction (XRD) and Raman scattering methods up to pressures of 43 GPa using a diamond anvil cell (DAC). With increasing pressure, the cubic pyrochlore in space group of Fd-3¯m with combining macron]m transforms to an orthorhombic structure (space group: Pnma) at 5.9 GPa and then to a monoclinic structure (space group: P2 1/c) at ~18 GPa. The structural evolution in CsTaWO 6 is a continuous process and experimental results suggest that the initial cubic phase has a tetragonal distortion at ambient conditions. Both XRD and Raman measurements indicate that themore » pressure-induced phase transitions in CsTaWO 6 are reversible. Lastly, these results may provide a structural explanation of previous experimental resistivity measurement results for the isostructural superconductor K(Cs)Os 2O 6 at high pressure conditions.« less

Lack of ferroelectricity in PbTiO3 at high pressures

NASA Astrophysics Data System (ADS)

Cohen, R. E.; Ahart, Muhtar; Hemley, Russell J.

The classic ferroelectric PbTiO3 continues to surprise. It was believed that ferroelectrics would become paraelectric under pressure, and this was observed in Raman experiments on PbTiO3. We predicted a morphotropic phase transition under pressure and verified it experimentally. At higher pressures it become paraelectric, but DFT predicted higher pressure ferroelectricity, and this seemed confirmed by experiments. New Second Harmonic Generation (SHG) measurements on PbTiO3 to 100 GPa and down to 10 K find no evidence for ferroelectricity above 20 GPa. Our DFT computations show centrosymmetric I4mcm as most stable from 20-90 GPa; I4mcm is the ground state of SrTiO3, and the rotations quench the polar instability. We predict a polar I4cm structure above 90 GPa, but the double well depth is very small. This work has been supported by the US ONR, ERC Advanced Grant ToMCaT, EFREE, CDAC, NSF and the Carnegie Institution for Science.

Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring.

PubMed

Dagdeviren, Canan; Su, Yewang; Joe, Pauline; Yona, Raissa; Liu, Yuhao; Kim, Yun-Soung; Huang, YongAn; Damadoran, Anoop R; Xia, Jing; Martin, Lane W; Huang, Yonggang; Rogers, John A

2014-08-05

The ability to measure subtle changes in arterial pressure using devices mounted on the skin can be valuable for monitoring vital signs in emergency care, detecting the early onset of cardiovascular disease and continuously assessing health status. Conventional technologies are well suited for use in traditional clinical settings, but cannot be easily adapted for sustained use during daily activities. Here we introduce a conformal device that avoids these limitations. Ultrathin inorganic piezoelectric and semiconductor materials on elastomer substrates enable amplified, low hysteresis measurements of pressure on the skin, with high levels of sensitivity (~0.005 Pa) and fast response times (~0.1 ms). Experimental and theoretical studies reveal enhanced piezoelectric responses in lead zirconate titanate that follow from integration on soft supports as well as engineering behaviours of the associated devices. Calibrated measurements of pressure variations of blood flow in near-surface arteries demonstrate capabilities for measuring radial artery augmentation index and pulse pressure velocity.

Duration of continuous positive airway pressure in premature infants

PubMed Central

Bamat, Nicolas; Jensen, Erik A.; Kirpalani, Haresh

2016-01-01

SUMMARY Continuous positive airway pressure (CPAP) has been used for respiratory support in premature infants for more than 40 years and is now a cornerstone of modern neonatal care. Clinical research on CPAP has primarily focused on understanding which devices and pressure sources best implement this therapy. In contrast, less research has examined the optimal duration over which CPAP is administered. We review this aspect of CPAP therapy. PMID:26948885

The Timer-Logger-Communicator for Continuous, Mobile Measurement of Wheelchair Pressure Reliefs

PubMed Central

Grip, Jeffrey C.; Merbitz, Charles T.

1985-01-01

A recently developed device which provides continuous, direct monitoring of the pressure-relief performance of persons confined to wheelchairs is reported. A custom portable computer records the data, which is transferred for analysis to an Apple IIe. The mobile computer can also signal the patient to relieve pressure based on preset criteria and the patient's performance. Teaching lift-offs to prevent ischial pressure sores is the object. Data collected with the device are used clinically and for research. Examples of such data are presented. The benefits of the device are reviewed.

Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals

PubMed Central

Peng, Rong-Chao; Yan, Wen-Rong; Zhang, Ning-Ling; Lin, Wan-Hua; Zhou, Xiao-Lin; Zhang, Yuan-Ting

2015-01-01

Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services. PMID:26393591

Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals.

PubMed

Peng, Rong-Chao; Yan, Wen-Rong; Zhang, Ning-Ling; Lin, Wan-Hua; Zhou, Xiao-Lin; Zhang, Yuan-Ting

2015-09-17

Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services.

Analysis of heterogeneous hydrological properties of a mountainous hillslope using intensive water flow measurements

NASA Astrophysics Data System (ADS)

Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Mizuyama, Takahisa; Tsutsumi, Daizo

2013-04-01

Heterogeneous hydrological properties in a foot slope area of mountainous hillslopes should be assessed to understand hydrological phenomena and their effects on discharge and sediment transport. In this study, we analyzed the high-resolution and three-dimensional water movement data to clarify the hydrological process, including heterogeneous phenomena, in detail. We continuously monitored the soil matric pressure head, psi, using 111 tensiometers installed at grid intervals of approximately 1 meter within the soil mantle at the study hillslope. Under a no-rainfall condition, the existence of perennial groundwater seepage flow was detected by exfiltration flux and temporal psi waveforms, which showed delayed responses, only to heavy storm events, and gradual recession limbs. The seepage water spread in the downslope direction and supplied water constantly to the lower section of the slope. At some points in the center of the slope, a perched saturated area was detected in the middle of soil layer, while psi exhibited negative values above the bedrock surface. These phenomena could be inferred partly from the bedrock topography and the distribution of soil hydraulic conductivity assumed from the result of penetration test. At the peak of a rainfall event, on the other hand, continuous high pressure zones (i.e., psi > 50 cmH2O) were generated in the right and left sections of the slope. Both of these high pressure zones converged at the lower region, showing a sharp psi spike up to 100 cmH2O. Along the high pressure zones, flux vectors showed large values and water exfiltration, indicating the occurrence of preferential flow. Moreover, the preferential flow occurred within the area beneath the perched water, indicating the existence of a weathered bedrock layer. This layer had low permeability, which prevented the vertical infiltration of water in the upper part of the layer, but had high permeability as a result of the fractures distributed heterogeneously inside the layer. These fractures acted as a preferential flow channel and flushed the water derived from lateral flow accumulated from the upslope area during the rainfall event. These phenomena occurring at the peak of rainfall event could not be inferred from the parameters derived from the penetration test.

Hybrid photonic signal processing

NASA Astrophysics Data System (ADS)

Ghauri, Farzan Naseer

This thesis proposes research of novel hybrid photonic signal processing systems in the areas of optical communications, test and measurement, RF signal processing and extreme environment optical sensors. It will be shown that use of innovative hybrid techniques allows design of photonic signal processing systems with superior performance parameters and enhanced capabilities. These applications can be divided into domains of analog-digital hybrid signal processing applications and free-space---fiber-coupled hybrid optical sensors. The analog-digital hybrid signal processing applications include a high-performance analog-digital hybrid MEMS variable optical attenuator that can simultaneously provide high dynamic range as well as high resolution attenuation controls; an analog-digital hybrid MEMS beam profiler that allows high-power watt-level laser beam profiling and also provides both submicron-level high resolution and wide area profiling coverage; and all optical transversal RF filters that operate on the principle of broadband optical spectral control using MEMS and/or Acousto-Optic tunable Filters (AOTF) devices which can provide continuous, digital or hybrid signal time delay and weight selection. The hybrid optical sensors presented in the thesis are extreme environment pressure sensors and dual temperature-pressure sensors. The sensors employ hybrid free-space and fiber-coupled techniques for remotely monitoring a system under simultaneous extremely high temperatures and pressures.

A novel membrane-integrated fermentation reactor system: application to pyruvic acid production in continuous culture by Torulopsis glabrata.

PubMed

Sawai, Hideki; Mimitsuka, Takashi; Minegishi, Shin-Ichi; Henmi, Masahiro; Yamada, Katsushige; Shimizu, Sakayu; Yonehara, Tetsu

2011-08-01

This paper describes the performance of a novel bio-reactor system, the membrane-integrated fermentation reactor (MFR), for efficient continuous fermentation. The MFR, equipped with an autoclavable polyvinylidene difluoride membrane, has normally been used for biological wastewater treatment. The productivity of the MFR system, applied to the continuous production of pyruvic acid by the yeast Torulopsis glabrata, was remarkably high. The volumetric productivity of pyruvic acid increased up to 4.2 g/l/h, about four times higher than that of batch fermentation. Moreover, the membrane was able to filter fermentation broth for more than 300 h without fouling even though the cell density of the fermentation broth reached 600 as OD(660). Transmembrane pressure, used as an indicator of membrane fouling, remained below 5 kPa throughout the continuous fermentation. These results clearly indicate that the MFR system is a simple and highly efficient system that is applicable to the fermentative production of a range of biochemicals.

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations.

PubMed

Toh, Ren Wei; Li, Jie Sheng; Wu, Jie

2018-01-04

A new reaction screening technology for organic synthesis was recently demonstrated by combining elements from both continuous micro-flow and conventional batch reactors, coined stop-flow micro-tubing (SFMT) reactors. In SFMT, chemical reactions that require high pressure can be screened in parallel through a safer and convenient way. Cross-contamination, which is a common problem in reaction screening for continuous flow reactors, is avoided in SFMT. Moreover, the commercially available light-permeable micro-tubing can be incorporated into SFMT, serving as an excellent choice for light-mediated reactions due to a more effective uniform light exposure, compared to batch reactors. Overall, the SFMT reactor system is similar to continuous flow reactors and more superior than batch reactors for reactions that incorporate gas reagents and/or require light-illumination, which enables a simple but highly efficient reaction screening system. Furthermore, any successfully developed reaction in the SFMT reactor system can be conveniently translated to continuous-flow synthesis for large scale production.

Dynamics anomaly in high-density amorphous ice between 0.7 and 1.1 GPa

NASA Astrophysics Data System (ADS)

Handle, Philip H.; Loerting, Thomas

2016-02-01

We studied high-density amorphous ices between 0.004 and 1.6 GPa by isobaric in situ volumetry and by subsequent ex situ x-ray diffraction and differential scanning calorimetry at 1 bar. Our observations indicate two processes, namely, relaxation in the amorphous matrix and crystallization, taking place at well-separated time scales. For this reason, we are able to report rate constants of crystallization kX and glass-transition temperatures Tg in an unprecedented pressure range. Tg's agree within ±3 K with earlier work in the small pressure range where there is overlap. Both Tg and kX show a pressure anomaly between 0.7 and 1.1 GPa, namely, a kX minimum and a Tg maximum. This anomalous pressure dependence suggests a continuous phase transition from high- (HDA) to very-high-density amorphous ice (VHDA) and faster hydrogen bond dynamics in VHDA. We speculate this phenomenology can be rationalized by invoking the crossing of a Widom line between 0.7 and 1.1 GPa emanating from a low-lying HDA-VHDA critical point. Furthermore, we interpret the volumetric relaxation of the amorphous matrix to be accompanied by viscosity change to explain the findings such that the liquid state can be accessed prior to the crystallization temperature TX at <0.4 GPa and >0.8 GPa.

Anxiety and depression are improved by continuous positive airway pressure treatments in obstructive sleep apnea.

PubMed

Li, Yu-Ying; Mazarakis, Thodoris; Shen, Yu-Chih; Yang, Miao-Chun; Chang, En-Ting; Wang, Hsiu-Mei

2016-08-01

Background Obstructive sleep apnea involves repeated nocturnal desaturation and sleep fragmentation that leads to poor sleep quality, anxiety, and depression. This study aimed to investigate short- and long-term improvements in the anxiety and depression of patients with different obstructive sleep apnea treatments. Methods This is a prospective, non-randomized hospital-based study evaluated 55 patients (46 male, 9 female) with obstructive sleep apnea. The patients were divided into three groups based on different treatment: uvulopalatopharyngoplasty group, continuous positive airway pressure group, and no treatment group (by their own decision). They completed the Beck Depression Inventory II, Beck Anxiety Inventory, and Pittsburgh Sleep Quality Index before treatment and at one and six months after treatment. Results Compared to the no treatment group, the surgery and continuous positive airway pressure groups had higher body mass index, AHI, and Epworth sleepiness scale, but no difference in Pittsburgh Sleep Quality Index, Chinese Health Questionnaire-12, Beck Depression Inventory II, and Beck Anxiety Inventory. The continuous positive airway pressure and surgery groups still had no improvements in Pittsburgh Sleep Quality Index, Chinese Health Questionnaire-12, Beck Depression Inventory II, and Beck Anxiety Inventory scores one month after treatment. At six months after treatment, the continuous positive airway pressure group had significantly decreased Pittsburgh Sleep Quality Index, Chinese Health Questionnaire-12, Beck Depression Inventory II, and Beck Anxiety Inventory, whereas the surgery group had significant difference in Beck Anxiety Inventory only and the no treatment group still had no significant difference in any of the parameters. Conclusions Continuous positive airway pressure can improve the sleep quality, quality of life, depression, and anxiety of obstructive sleep apnea patients after six months of treatment. However, surgery can significantly improve anxiety only in the same period.

Strength and processing properties of wet-formed hardboards from recycled corrugated containers and commercial hardboard fibers

Treesearch

J. F. Hunt; C. B. Vick

1999-01-01

Recycled paper fiber recovered from our municipal solid waste stream could potentially be used in structural hardboard products. This study compares strength properties and processing variables of wet-formed high-density hardboard panels made from recycled old corrugated container (OCC) fibers and virgin hardboard fibers using continuous pressure during drying. The...

"The Land of Opportunity Doesn't Apply to Everyone": The Immigrant Experience, Race, and Asian American Career Choices

ERIC Educational Resources Information Center

Poon, OiYan

2014-01-01

Despite their popular portrayal as high achieving and structurally incorporated, race continues to shape the career choices of Asian American college students. As second-generation Americans, Asian Americans negotiate a constellation of factors when deciding their career choices, most notably, pressures from immigrant parents, awareness of labor…

Aim Higher: Lofty Goals and an Aligned System Keep a High Performer on Top

ERIC Educational Resources Information Center

McCommons, David P.

2014-01-01

Every school district is feeling the pressure to ensure higher academic achievement for all students. A focus on professional learning for an administrative team not only improves student learning and achievement, but also assists in developing a systemic approach for continued success. This is how the Fox Chapel Area School District in…

Return of neonatal CPAP resistance - the Medijet device family examined using in vitro flow simulations.

PubMed

Falk, Markus; Donaldsson, Snorri; Jonsson, Baldvin; Drevhammar, Thomas

2017-11-01

Medijet nasal continuous positive airway pressure (CPAP) generators are a family of devices developed from the Benveniste valve. Previous studies have shown that the in vitro performance of the Medijet disposable generator was similar to the Neopuff resistor system. We hypothesised that resistance would be the main mechanism of CPAP generation in the Medijet disposable generator. The in vitro performance of the Medijet reusable and disposable systems, the Neopuff resistor system and the Benveniste and Infant Flow nonresistor systems were investigated using static and dynamic bench tests. Large differences in performance were found between the different systems. The disposable Medijet demonstrated high resistance, low pressure stability and high imposed work of breathing. The results also showed that encapsulating the Benveniste valve changed it into a resistor system. The main mechanism of CPAP generation for the disposable Medijet generator was resistance. The Medijet device family showed increasing resistance with each design generation. The high resistance of the Medijet disposable generator could be of great value when examining the clinical importance of pressure stability. Our results suggest that this device should be used cautiously in patients where pressure-stable CPAP is believed to be clinically important. ©2017 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Wavelength modulation spectroscopy near 5 μm for carbon monoxide sensing in a high-pressure kerosene-fueled liquid rocket combustor

NASA Astrophysics Data System (ADS)

Lee, Daniel D.; Bendana, Fabio A.; Schumaker, S. Alexander; Spearrin, R. Mitchell

2018-05-01

A laser absorption sensor was developed for carbon monoxide (CO) sensing in high-pressure, fuel-rich combustion gases associated with the internal conditions of hydrocarbon-fueled liquid bipropellant rockets. An absorption feature near 4.98 μm, comprised primarily of two rovibrational lines from the P-branch of the fundamental band, was selected to minimize temperature sensitivity and spectral interference with other combustion gas species at the extreme temperatures (> 3000 K) and pressures (> 50 atm) in the combustion chamber environment. A scanned wavelength modulation spectroscopy technique (1 f-normalized 2 f detection) is utilized to infer species concentration from CO absorption, and mitigate the influence of non-absorption transmission losses and noise associated with the harsh sooting combustor environment. To implement the sensing strategy, a continuous-wave distributed-feedback (DFB) quantum cascade laser (QCL) was coupled to a hollow-core optical fiber for remote mid-infrared light delivery to the test article, with high-bandwidth light detection by a direct-mounted photovoltaic detector. The method was demonstrated to measure time-resolved CO mole fraction over a range of oxidizer-to-fuel ratios and pressures (20-70 atm) in a single-element-injector RP-2-GOx rocket combustor.

Use of Acoustic Emission and Pattern Recognition for Crack Detection of a Large Carbide Anvil

PubMed Central

Chen, Bin; Wang, Yanan; Yan, Zhaoli

2018-01-01

Large-volume cubic high-pressure apparatus is commonly used to produce synthetic diamond. Due to the high pressure, high temperature and alternative stresses in practical production, cracks often occur in the carbide anvil, thereby resulting in significant economic losses or even casualties. Conventional methods are unsuitable for crack detection of the carbide anvil. This paper is concerned with acoustic emission-based crack detection of carbide anvils, regarded as a pattern recognition problem; this is achieved using a microphone, with methods including sound pulse detection, feature extraction, feature optimization and classifier design. Through analyzing the characteristics of background noise, the cracked sound pulses are separated accurately from the originally continuous signal. Subsequently, three different kinds of features including a zero-crossing rate, sound pressure levels, and linear prediction cepstrum coefficients are presented for characterizing the cracked sound pulses. The original high-dimensional features are adaptively optimized using principal component analysis. A hybrid framework of a support vector machine with k nearest neighbors is designed to recognize the cracked sound pulses. Finally, experiments are conducted in a practical diamond workshop to validate the feasibility and efficiency of the proposed method. PMID:29382144

Use of Acoustic Emission and Pattern Recognition for Crack Detection of a Large Carbide Anvil.

PubMed

Chen, Bin; Wang, Yanan; Yan, Zhaoli

2018-01-29

Large-volume cubic high-pressure apparatus is commonly used to produce synthetic diamond. Due to the high pressure, high temperature and alternative stresses in practical production, cracks often occur in the carbide anvil, thereby resulting in significant economic losses or even casualties. Conventional methods are unsuitable for crack detection of the carbide anvil. This paper is concerned with acoustic emission-based crack detection of carbide anvils, regarded as a pattern recognition problem; this is achieved using a microphone, with methods including sound pulse detection, feature extraction, feature optimization and classifier design. Through analyzing the characteristics of background noise, the cracked sound pulses are separated accurately from the originally continuous signal. Subsequently, three different kinds of features including a zero-crossing rate, sound pressure levels, and linear prediction cepstrum coefficients are presented for characterizing the cracked sound pulses. The original high-dimensional features are adaptively optimized using principal component analysis. A hybrid framework of a support vector machine with k nearest neighbors is designed to recognize the cracked sound pulses. Finally, experiments are conducted in a practical diamond workshop to validate the feasibility and efficiency of the proposed method.

Does personality play a role in continuous positive airway pressure compliance?

PubMed Central

Maschauer, Emily L.; Fairley, Donna M.

2017-01-01

Key points Continuous positive airway pressure (CPAP) adherence is low among individuals with obstructive sleep apnoea. Type D personality and high scores on the depression and hypochondriasis scales on the Minnesota Multiphasic Personality Inventory (MMPI) have been identified as factors contributing to non-compliance with CPAP. Further research into personality type may assist in understanding why some people adhere to CPAP, while others fail. Obstructive sleep apnoea (OSA) is a condition characterised by repetitive, intermittent partial or complete collapse/obstruction of the upper airway during sleep. Continuous positive airway pressure (CPAP) is highly efficacious in treating OSA but its effectiveness is limited due to suboptimal acceptance and adherence rates, with as many as 50% of OSA patients discontinuing CPAP treatment within the first year. Until recently, research has focused on examining mechanistic and demographic factors that could explain nonadherence (e.g. age, sex, race and education level) with limited applicability in a prospective or clinical manner. More recent research has focused on personality factors or types of patients with OSA who comply and do not comply with CPAP adherence in an attempt to enhance the accuracy of predicting treatment compliance. Type D personality has been found to be prevalent in one third of patients with OSA. The presence of Type D personality increases noncompliance and poor treatment outcomes due to negative affectivity, social inhibition, unhealthy lifestyle, and a reluctance to consult and/or follow medical advice. Conversely, individuals who are more likely to adhere to CPAP treatment tend to have a high internal locus of control and high self-efficacy, self-refer for treatment, and have active coping skills. By assessing personality and coping skills, the clinician may gain insight into the likelihood of a patient’s adherence to treatment. If the patient displays potential risk factors for CPAP noncompliance, the clinician can offer the patient education, refer them to a support group, engage in behavioural/motivational therapy and undertake regular follow-up visits or phone calls incorporating troubleshooting to increase CPAP adherence, especially in individuals with Type D personality. PMID:28289449

Pressure-tuned superconductivity and normal-state behavior in Ba ( Fe 0.943 Co 0.057 ) 2 As 2 near the antiferromagnetic boundary

DOE PAGES

Liu, W.; Wu, Y. F.; Li, X. J.; ...

2018-04-23

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba (Fe 1 - xCo x) 2 As 2 single crystals with x = 0.057, which is near the antiferromagnetic instability. Resistivity ρ = ρ 0 + AT n was studied under applied pressure up to 7.90 GPa. The parameter n approaches a minimum value of n ≈ 1 at amore » critical pressure P c = 3.65 GPa. Near P c, the superconducting transition temperature T c reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. Finally, these results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum T c.« less

Pressure-tuned superconductivity and normal-state behavior in Ba ( Fe 0.943 Co 0.057 ) 2 As 2 near the antiferromagnetic boundary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, W.; Wu, Y. F.; Li, X. J.

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba (Fe 1 - xCo x) 2 As 2 single crystals with x = 0.057, which is near the antiferromagnetic instability. Resistivity ρ = ρ 0 + AT n was studied under applied pressure up to 7.90 GPa. The parameter n approaches a minimum value of n ≈ 1 at amore » critical pressure P c = 3.65 GPa. Near P c, the superconducting transition temperature T c reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. Finally, these results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum T c.« less

Plasma pressure distribution at the geocentric distances smaller than 15 Re and the structure of magnetospheric current systems

NASA Astrophysics Data System (ADS)

Kirpichev, Igor; Antonova, Elizaveta

We analyzed the characteristics of the plasma region surrounding the Earth at the geocentric distances between 6 and 15 Re using the data of THEMIS mission. To calculate plasma pressure including ion and electron contributions we have used the particle spectra measured by ESA and SST instruments. The magnetic field was obtained from the FGM magnetometer data. We take into account the daytime compression of the magnetic field lines and the shift of the minimal value of the magnetic field to higher latitudes. The obtained averaged distributions of plasma pressure, of pressure anisotropy, and of magnetic field near the equatorial plane showed the presence of a ring-shaped structure surrounding the Earth at the geocentric distances till the dayside magnetopause near noon. Plasma pressure gradients in the analyzed region have mainly earthward direction which means the existence of westward directed transverse currents. We obtain the values of such current densities and integral currents along field lines during quite geomagnetic conditions suggesting the validity of the condition of the magnetostatic equilibrium. We show that transverse currents in the high latitude magnetosphere have the ring-like structure forming the high latitude continuation of the ordinary ring current. The obtained data base is used for the creation of the model of the pressure distribution during different IMF and solar wind conditions.

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care

NASA Astrophysics Data System (ADS)

Chen, Lisa Y.; Tee, Benjamin C.-K.; Chortos, Alex L.; Schwartz, Gregor; Tse, Victor; J. Lipomi, Darren; Wong, H.-S. Philip; McConnell, Michael V.; Bao, Zhenan

2014-10-01

Continuous monitoring of internal physiological parameters is essential for critical care patients, but currently can only be practically achieved via tethered solutions. Here we report a wireless, real-time pressure monitoring system with passive, flexible, millimetre-scale sensors, scaled down to unprecedented dimensions of 1 × 1 × 0.1 cubic millimeters. This level of dimensional scaling is enabled by novel sensor design and detection schemes, which overcome the operating frequency limits of traditional strategies and exhibit insensitivity to lossy tissue environments. We demonstrate the use of this system to capture human pulse waveforms wirelessly in real time as well as to monitor in vivo intracranial pressure continuously in proof-of-concept mice studies using sensors down to 2.5 × 2.5 × 0.1 cubic millimeters. We further introduce printable wireless sensor arrays and show their use in real-time spatial pressure mapping. Looking forward, this technology has broader applications in continuous wireless monitoring of multiple physiological parameters for biomedical research and patient care.

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care.

PubMed

Chen, Lisa Y; Tee, Benjamin C-K; Chortos, Alex L; Schwartz, Gregor; Tse, Victor; Lipomi, Darren J; Wong, H-S Philip; McConnell, Michael V; Bao, Zhenan

2014-10-06

Continuous monitoring of internal physiological parameters is essential for critical care patients, but currently can only be practically achieved via tethered solutions. Here we report a wireless, real-time pressure monitoring system with passive, flexible, millimetre-scale sensors, scaled down to unprecedented dimensions of 1 × 1 × 0.1 cubic millimeters. This level of dimensional scaling is enabled by novel sensor design and detection schemes, which overcome the operating frequency limits of traditional strategies and exhibit insensitivity to lossy tissue environments. We demonstrate the use of this system to capture human pulse waveforms wirelessly in real time as well as to monitor in vivo intracranial pressure continuously in proof-of-concept mice studies using sensors down to 2.5 × 2.5 × 0.1 cubic millimeters. We further introduce printable wireless sensor arrays and show their use in real-time spatial pressure mapping. Looking forward, this technology has broader applications in continuous wireless monitoring of multiple physiological parameters for biomedical research and patient care.

Modeling of Highly Instrumented Honeywell Turbofan Engine Tested with Ice Crystal Ingestion in the NASA Propulsion System Laboratory

NASA Technical Reports Server (NTRS)

Veres, Joseph P.; Jorgenson, Philip C. E.; Jones, Scott M.

2016-01-01

The Propulsion Systems Laboratory (PSL), an altitude test facility at NASA Glenn Research Center, has been used to test a highly instrumented turbine engine at simulated altitude operating conditions. This is a continuation of the PSL testing that successfully duplicated the icing events that were experienced in a previous engine (serial LF01) during flight through ice crystal clouds, which was the first turbofan engine tested in PSL. This second model of the ALF502R-5A serial number LF11 is a highly instrumented version of the previous engine. The PSL facility provides a continuous cloud of ice crystals with controlled characteristics of size and concentration, which are ingested by the engine during operation at simulated altitudes. Several of the previous operating points tested in the LF01 engine were duplicated to confirm repeatability in LF11. The instrumentation included video cameras to visually illustrate the accretion of ice in the low pressure compressor (LPC) exit guide vane region in order to confirm the ice accretion, which was suspected during the testing of the LF01. Traditional instrumentation included static pressure taps in the low pressure compressor inner and outer flow path walls, as well as total pressure and temperature rakes in the low pressure compressor region. The test data was utilized to determine the losses and blockages due to accretion in the exit guide vane region of the LPC. Multiple data points were analyzed with the Honeywell Customer Deck. A full engine roll back point was modeled with the Numerical Propulsion System Simulation (NPSS) code. The mean line compressor flow analysis code with ice crystal modeling was utilized to estimate the parameters that indicate the risk of accretion, as well as to estimate the degree of blockage and losses caused by accretion during a full engine roll back point. The analysis provided additional validation of the icing risk parameters within the LPC, as well as the creation of models for estimating the rates of blockage growth and losses.

Influence of Exercise Modality on Cerebral-Ocular Hemodynamics and Pressures

NASA Technical Reports Server (NTRS)

Scott, J.; Martin, D.; Crowell, B.; Goetchius, E.; Seponski, C.; Gonzales, R.; Matz, T.; Ploutz-Snyder, R.; Stenger, M.; Ploutz-Snyder, L.

2016-01-01

Background: Moderate and high intensity aerobic or resistance exercise has clearly identified benefits for cardiac, muscle, and bone health. However, the impact of such exercise - either as a mitigating or an exacerbating factor - on the development of the visual impairment and intracranial pressure syndrome (VIIP) is unknown. Accordingly, our aim was to characterize the effect of an acute bout of resistance (RE), moderate-intensity continuous (CE), and high-intensity interval exercise (IE) during a cephalad fluid shift on cerebral-ocular hemodynamics and pressures. Methods: 10 male subjects (36 plus or minus 9 years) completed 4 testing days in a 15 degree head-down tilt (HDT): (1) assessment of maximum volume of O (sub 2), (2) RE session (4 sets of 12 repetition maximum leg press exercise), (3) CE session (30 minutes of cycling at 60 percent maximum volume of O (sub 2)), and (4) IE session (4 by 4-minute intervals of exercise at 85 percent maximum volume of O (sub 2) with 3-minute active rest periods). During each session, blood flow (Vivid-e, GE Healthcare) in extracranial arteries (common carotid artery, CCA; internal carotid artery, ICA; external carotid artery, ECA and vertebral artery, VA), and mean blood flow velocity in middle cerebral artery (MCA), internal jugular pressure (IJP; VeinPress), and intraocular pressure (IOP; Icare PRO) were measured at rest, at the end of each resistance or interval set, and every 5 minutes during continuous exercise. Translaminar pressure gradient (TLPG) was estimated by subtracting IJP from IOP. Results: There were no differences across days in pre-exercise resting blood flows or pressures. IOP decreased slightly from HDT rest (20.2 plus or minus 2.3 millimeters of mercury) to exercise (RE: 19.2 plus or minus 2.8 millimeters of mercury; CE: 18.9 plus or minus 3.2 millimeters of mercury; IE: 20.1 plus or minus 2.8 millimeters of mercury), while IJP decreased during CE (31.6 plus or minus 9.5 millimeters of mercury) and RE (32.0 plus or minus 8.1 millimeters of mercury), and increased during IE (35.1 plus or minus 9.5 millimeters of mercury) from HDT rest (33.3 plus or minus 6.5 millimeters of mercury). Estimated TLPG was increased during IE only. Compared to RE and CE, IE resulted in the greatest increase in MCA blood flow velocity and extracranial artery blood flow. Conclusions: These preliminary results suggest that high-intensity IE acutely increases cerebral blood flow, IJP, and TLPG. Alterations in TLPG is one mechanism that may contribute to optic nerve sheath edema in astronauts. Accordingly, acutely raising IOP and/or orbital pressure during exercise could optimize cerebral-ocular pressures during spaceflight.

Single-crystal Brillouin spectroscopy with CO{sub 2} laser heating and variable q

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jin S.; Bass, Jay D.; Zhu, Gaohua

2015-06-15

We describe a Brillouin spectroscopy system integrated with CO{sub 2} laser-heating and Raman spectroscopic capabilities. Temperature is determined by measurements of the grey-body thermal radiation emitted by the hot sample, with the system response calibrated relative to a standard tungsten ribbon lamp. High-pressure laser-heating Brillouin scattering measurements of acoustic velocities on liquid water and ice compressed in a diamond-anvil cell were performed at temperatures up to 2500 ± 150 K at high pressure. Single-crystal laser-heating Brillouin measurements were made on the (111) plane of San Carlos olivine at ∼13 GPa, 1300 ± 200 K. The pressure as measured by rubymore » fluorescence is shown to be within ±0.5 GPa of the pressure on the olivine sample during laser heating when KCl and KBr are used as pressure-transmitting media. In addition, the system is designed for continuously variable scattering angles from forward scattering (near 0° scattering angle) up to near back scattering (∼141°). This novel setup allows us to probe a wide range of wave vectors q for investigation of phonon dispersion on, for example, crystals with large unit cells (on the scale of hundreds of nm)« less

Thermally-enhanced oil recovery method and apparatus

DOEpatents

Stahl, Charles R.; Gibson, Michael A.; Knudsen, Christian W.

1987-01-01

A thermally-enhanced oil recovery method and apparatus for exploiting deep well reservoirs utilizes electric downhole steam generators to provide supplemental heat to generate high quality steam from hot pressurized water which is heated at the surface. A downhole electric heater placed within a well bore for local heating of the pressurized liquid water into steam is powered by electricity from the above-ground gas turbine-driven electric generators fueled by any clean fuel such as natural gas, distillate or some crude oils, or may come from the field being stimulated. Heat recovered from the turbine exhaust is used to provide the hot pressurized water. Electrical power may be cogenerated and sold to an electric utility to provide immediate cash flow and improved economics. During the cogeneration period (no electrical power to some or all of the downhole units), the oil field can continue to be stimulated by injecting hot pressurized water, which will flash into lower quality steam at reservoir conditions. The heater includes electrical heating elements supplied with three-phase alternating current or direct current. The injection fluid flows through the heater elements to generate high quality steam to exit at the bottom of the heater assembly into the reservoir. The injection tube is closed at the bottom and has radial orifices for expanding the injection fluid to reservoir pressure.

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

PubMed Central

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

2012-01-01

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

Continuous blood pressure recordings simultaneously with functional brain imaging: studies of the glymphatic system

NASA Astrophysics Data System (ADS)

Zienkiewicz, Aleksandra; Huotari, Niko; Raitamaa, Lauri; Raatikainen, Ville; Ferdinando, Hany; Vihriälä, Erkki; Korhonen, Vesa; Myllylä, Teemu; Kiviniemi, Vesa

2017-03-01

The lymph system is responsible for cleaning the tissues of metabolic waste products, soluble proteins and other harmful fluids etc. Lymph flow in the body is driven by body movements and muscle contractions. Moreover, it is indirectly dependent on the cardiovascular system, where the heart beat and blood pressure maintain force of pressure in lymphatic channels. Over the last few years, studies revealed that the brain contains the so-called glymphatic system, which is the counterpart of the systemic lymphatic system in the brain. Similarly, the flow in the glymphatic system is assumed to be mostly driven by physiological pulsations such as cardiovascular pulses. Thus, continuous measurement of blood pressure and heart function simultaneously with functional brain imaging is of great interest, particularly in studies of the glymphatic system. We present our MRI compatible optics based sensing system for continuous blood pressure measurement and show our current results on the effects of blood pressure variations on cerebral brain dynamics, with a focus on the glymphatic system. Blood pressure was measured simultaneously with near-infrared spectroscopy (NIRS) combined with an ultrafast functional brain imaging (fMRI) sequence magnetic resonance encephalography (MREG, 3D brain 10 Hz sampling rate).

The Supraglottic Effect of a Reduction in Expiratory Mask Pressure During Continuous Positive Airway Pressure

PubMed Central

Masdeu, Maria J.; Patel, Amit V.; Seelall, Vijay; Rapoport, David M.; Ayappa, Indu

2012-01-01

Study Objectives: Patients with obstructive sleep apnea may have difficulty exhaling against positive pressure, hence limiting their acceptance of continuous positive airway pressure (CPAP). C-Flex is designed to improve comfort by reducing pressure in the mask during expiration proportionally to expiratory airflow (3 settings correspond to increasing pressure changes). When patients use CPAP, nasal resistance determines how much higher supraglottic pressure is than mask pressure. We hypothesized that increased nasal resistance results in increased expiratory supraglottic pressure swings that could be mitigated by the effects of C-Flex on mask pressure. Design: Cohort study. Setting: Sleep center. Participants: Seventeen patients with obstructive sleep apnea/hypopnea syndrome and a mechanical model of the upper airway. Interventions: In patients on fixed CPAP, CPAP with different C-Flex levels was applied multiple times during the night. In the model, 2 different respiratory patterns and resistances were tested. Measurements and Results: Airflow, expiratory mask, and supraglottic pressures were measured on CPAP and on C-Flex. Swings in pressure during expiration were determined. On CPAP, higher nasal resistance produced greater expiratory pressure swings in the supraglottis in the patients and in the model, as expected. C-Flex 3 produced expiratory drops in mask pressure (range −0.03 to −2.49 cm H2O) but mitigated the expira-tory pressure rise in the supraglottis only during a sinusoidal respiratory pattern in the model. Conclusions: Expiratory changes in mask pressure induced by C-Flex did not uniformly transmit to the supraglottis in either patients with obstructive sleep apnea on CPAP or in a mechanical model of the upper airway with fixed resistance. Data suggest that the observed lack of expiratory drop in supraglottic pressure swings is related to dynamics of the C-Flex algorithm. Citation: Masdeu MJ; Patel AV; Seelall V; Rapoport DM; Ayappa I. The supraglottic effect of a reduction in expiratory mask pressure during continuous positive airway pressure. SLEEP 2012;35(2):263-272. PMID:22294817

Rapid compression transforms interfacial monolayers of pulmonary surfactant.

PubMed

Crane, J M; Hall, S B

2001-04-01

Films of pulmonary surfactant in the lung are metastable at surface pressures well above the equilibrium spreading pressure of 45 mN/m but commonly collapse at that pressure when compressed in vitro. The studies reported here determined the effect of compression rate on the ability of monolayers containing extracted calf surfactant at 37 degrees C to maintain very high surface pressures on the continuous interface of a captive bubble. Increasing the rate from 2 A(2)/phospholipid/min (i.e., 3% of (initial area at 40 mN/m)/min) to 23%/s produced only transient increases to 48 mN/m. Above a threshold rate of 32%/s, however, surface pressures reached > 68 mN/m. After the rapid compression, static films maintained surface pressures within +/- 1 mN/m both at these maximum values and at lower pressures following expansion at < 5%/min to > or = 45 mN/m. Experiments with dimyristoyl phosphatidylcholine at 37 degrees C produced similar results. These findings indicate that compression at rates comparable to values in the lungs can transform at least some phospholipid monolayers from a form that collapses readily at the equilibrium spreading pressure to one that is metastable for prolonged periods at higher pressures. Our results also suggest that transformation of surfactant films can occur without refinement of their composition.

Taking the pressure off the spring: the case of rebounding smoking rates when antitobacco campaigns ceased.

PubMed

Dono, Joanne; Bowden, Jacqueline; Kim, Susan; Miller, Caroline

2018-04-07

Smoking rates have been compared with a spring, requiring continuous downward pressure against protobacco forces, rather than a screw, which once driven down stays down. Quality antitobacco mass media campaigns put downward pressure on smoking rates. The suspension of a major Australian state campaign provided a natural experiment to assess effects on smoking. Furthermore, we document the positive influence of robust monitoring and mature advocacy on the political decision to reinstate funding. We also document the misuse by industry of South Australian smoking data from the period between Australia's implementation and subsequent evaluation of plain packaging. A time series analysis was used to examine monthly smoking prevalence trends at each of four intervention points: (A) commencement of high-intensity mass media campaign (August 2010); (B) introduction of plain packaging (December 2012), (C) defunding of campaign (July 2013); and (D) reinstatement of moderate-intensity campaign (July 2014). The suspension of the antitobacco campaign was disruptive to achieving smoking prevalence targets. There was an absence of a downward monthly smoking prevalence trajectory during the non-campaign period. Moreover, there was a significant decline in smoking prevalence during the period of high-intensity advertising, which continued after the introduction of plain packaging laws, and at the recommencement of campaign activity. While the observed declines in smoking prevalence are likely due to a combination of interventions and cannot be attributed exclusively to antitobacco advertising, the results reinforce the political decision to reinstate the campaign and demonstrate the need for maintained investment to keep downward pressure on smoking rates. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Beneficial cardiovascular effects of reducing exposure to particulate air pollution with a simple facemask.

PubMed

Langrish, Jeremy P; Mills, Nicholas L; Chan, Julian Kk; Leseman, Daan Lac; Aitken, Robert J; Fokkens, Paul Hb; Cassee, Flemming R; Li, Jing; Donaldson, Ken; Newby, David E; Jiang, Lixin

2009-03-13

Exposure to air pollution is an important risk factor for cardiovascular morbidity and mortality, and is associated with increased blood pressure, reduced heart rate variability, endothelial dysfunction and myocardial ischaemia. Our objectives were to assess the cardiovascular effects of reducing air pollution exposure by wearing a facemask. In an open-label cross-over randomised controlled trial, 15 healthy volunteers (median age 28 years) walked on a predefined city centre route in Beijing in the presence and absence of a highly efficient facemask. Personal exposure to ambient air pollution and exercise was assessed continuously using portable real-time monitors and global positional system tracking respectively. Cardiovascular effects were assessed by continuous 12-lead electrocardiographic and ambulatory blood pressure monitoring. Ambient exposure (PM2.5 86 +/- 61 vs 140 +/- 113 mug/m3; particle number 2.4 +/- 0.4 vs 2.3 +/- 0.4 x 104 particles/cm3), temperature (29 +/- 1 vs 28 +/- 3 degrees C) and relative humidity (63 +/- 10 vs 64 +/- 19%) were similar (P > 0.05 for all) on both study days. During the 2-hour city walk, systolic blood pressure was lower (114 +/- 10 vs 121 +/- 11 mmHg, P < 0.01) when subjects wore a facemask, although heart rate was similar (91 +/- 11 vs 88 +/- 11/min; P > 0.05). Over the 24-hour period heart rate variability increased (SDNN 65.6 +/- 11.5 vs 61.2 +/- 11.4 ms, P < 0.05; LF-power 919 +/- 352 vs 816 +/- 340 ms2, P < 0.05) when subjects wore the facemask. Wearing a facemask appears to abrogate the adverse effects of air pollution on blood pressure and heart rate variability. This simple intervention has the potential to protect susceptible individuals and prevent cardiovascular events in cities with high concentrations of ambient air pollution.

High-intensity interval training, but not continuous training, reverses right ventricular hypertrophy and dysfunction in a rat model of pulmonary hypertension.

PubMed

Brown, Mary Beth; Neves, Evandro; Long, Gary; Graber, Jeremy; Gladish, Brett; Wiseman, Andrew; Owens, Matthew; Fisher, Amanda J; Presson, Robert G; Petrache, Irina; Kline, Jeffrey; Lahm, Tim

2017-02-01

Exercise is beneficial in pulmonary arterial hypertension (PAH), although studies to date indicate little effect on the elevated pulmonary pressures or maladaptive right ventricle (RV) hypertrophy associated with the disease. For chronic left ventricle failure, high-intensity interval training (HIIT) promotes greater endothelial stimulation and superior benefit than customary continuous exercise training (CExT); however, HIIT has not been tested for PAH. Therefore, here we investigated acute and chronic responses to HIIT vs. CExT in a rat model of monocrotaline (MCT)-induced mild PAH. Six weeks of treadmill training (5 times/wk) were performed, as either 30 min HIIT or 60 min low-intensity CExT. To characterize acute hemodynamic responses to the two approaches, novel recordings of simultaneous pulmonary and systemic pressures during running were obtained at pre- and 2, 4, 6, and 8 wk post-MCT using long-term implantable telemetry. MCT-induced decrement in maximal aerobic capacity was ameliorated by both HIIT and CExT, with less pronounced pulmonary vascular remodeling and no increase in RV inflammation or apoptosis observed. Most importantly, only HIIT lowered RV systolic pressure, RV hypertrophy, and total pulmonary resistance, and prompted higher cardiac index that was complemented by a RV increase in the positive inotrope apelin and reduced fibrosis. HIIT prompted a markedly pulsatile pulmonary pressure during running and was associated with greater lung endothelial nitric oxide synthase after 6 wk. We conclude that HIIT may be superior to CExT for improving hemodynamics and maladaptive RV hypertrophy in PAH. HIIT's superior outcomes may be explained by more favorable pulmonary vascular endothelial adaptation to the pulsatile HIIT stimulus.

High-intensity interval training, but not continuous training, reverses right ventricular hypertrophy and dysfunction in a rat model of pulmonary hypertension

PubMed Central

Neves, Evandro; Long, Gary; Graber, Jeremy; Gladish, Brett; Wiseman, Andrew; Owens, Matthew; Fisher, Amanda J.; Presson, Robert G.; Petrache, Irina; Kline, Jeffrey; Lahm, Tim

2017-01-01

Exercise is beneficial in pulmonary arterial hypertension (PAH), although studies to date indicate little effect on the elevated pulmonary pressures or maladaptive right ventricle (RV) hypertrophy associated with the disease. For chronic left ventricle failure, high-intensity interval training (HIIT) promotes greater endothelial stimulation and superior benefit than customary continuous exercise training (CExT); however, HIIT has not been tested for PAH. Therefore, here we investigated acute and chronic responses to HIIT vs. CExT in a rat model of monocrotaline (MCT)-induced mild PAH. Six weeks of treadmill training (5 times/wk) were performed, as either 30 min HIIT or 60 min low-intensity CExT. To characterize acute hemodynamic responses to the two approaches, novel recordings of simultaneous pulmonary and systemic pressures during running were obtained at pre- and 2, 4, 6, and 8 wk post-MCT using long-term implantable telemetry. MCT-induced decrement in maximal aerobic capacity was ameliorated by both HIIT and CExT, with less pronounced pulmonary vascular remodeling and no increase in RV inflammation or apoptosis observed. Most importantly, only HIIT lowered RV systolic pressure, RV hypertrophy, and total pulmonary resistance, and prompted higher cardiac index that was complemented by a RV increase in the positive inotrope apelin and reduced fibrosis. HIIT prompted a markedly pulsatile pulmonary pressure during running and was associated with greater lung endothelial nitric oxide synthase after 6 wk. We conclude that HIIT may be superior to CExT for improving hemodynamics and maladaptive RV hypertrophy in PAH. HIIT’s superior outcomes may be explained by more favorable pulmonary vascular endothelial adaptation to the pulsatile HIIT stimulus. PMID:27784688

46 CFR 54.01-25 - Miscellaneous pressure components (modifies UG-11).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Miscellaneous pressure components (modifies UG-11). 54.01-25 Section 54.01-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-25 Miscellaneous pressure components (modifies UG-11). (a) Pressure components for pressure...

46 CFR 54.01-25 - Miscellaneous pressure components (modifies UG-11).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Miscellaneous pressure components (modifies UG-11). 54.01-25 Section 54.01-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-25 Miscellaneous pressure components (modifies UG-11). (a) Pressure components for pressure...

46 CFR 54.01-25 - Miscellaneous pressure components (modifies UG-11).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Miscellaneous pressure components (modifies UG-11). 54.01-25 Section 54.01-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-25 Miscellaneous pressure components (modifies UG-11). (a) Pressure components for pressure...

46 CFR 54.01-25 - Miscellaneous pressure components (modifies UG-11).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Miscellaneous pressure components (modifies UG-11). 54.01-25 Section 54.01-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-25 Miscellaneous pressure components (modifies UG-11). (a) Pressure components for pressure...

46 CFR 54.01-25 - Miscellaneous pressure components (modifies UG-11).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Miscellaneous pressure components (modifies UG-11). 54.01-25 Section 54.01-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-25 Miscellaneous pressure components (modifies UG-11). (a) Pressure components for pressure...

Seafloor Uplift in Middle Valley, Juan de Fuca Ridge: New High-Resolution Pressure Data

NASA Astrophysics Data System (ADS)

Inderbitzen, K. E.; Becker, K.; Davis, E. E.

2011-12-01

Currently, in-situ seafloor and basement pressures are continuously monitored and recorded by an ODP subseafloor hydrogeological observatory (CORK) located in Middle Valley, Juan de Fuca Ridge. Hole 857D was drilled in 1991 in thickly sedimented crust to a depth of 936 mbsf and instrumented with an original CORK that was replaced in 1996. A large hydrothermal field (Dead Dog) lies roughly 1.7 km north of the hole, and two isolated chimneys and several diffuse flow sites are located ~800 meters northeast. The borehole and the vent fields have been visited periodically by submersible/ROV since 1999. Recent results from the CORK at 857D have shown apparent seafloor uplift, supported by depth records from the submersible Alvin. A constant rate of pressure change of ~6 kPa/yr, from its initiation in 2005 to the visit in 2010, has reduced mean seafloor pressure by ~28 kPa, equivalent to nearly 3 meters of head. This uplift rate is several times the typical pre-eruption inflation rates observed at Axial Seamount further south along the Juan de Fuca Ridge. Initially, the apparent uplift at 857D did not seem to have any effect on local high-temperature hydrothermal venting, however recent operations in Middle Valley revealed distinct changes at not only the hydrothermal field to the northeast, but also a shutdown of high-temperature venting to the north of 857D. We will present new data from Middle Valley, including the first year of data collected by a high-resolution pressure data logger deployed at 857D in June, 2010.

Ambulatory blood pressure response to a bout of HIIT in metabolic syndrome patients.

PubMed

Ramirez-Jimenez, M; Morales-Palomo, F; Pallares, J G; Mora-Rodriguez, Ricardo; Ortega, J F

2017-07-01

The effectiveness of exercise to lower blood pressure may depend on the type and intensity of exercise. We study the short-term (i.e., 14-h) effects of a bout of high-intensity aerobic interval training (HIIT) on blood pressure in metabolic syndrome (MetS) patients. Nineteen MetS patients (55.2 ± 7.3 years, 6 women) entered the study. Eight of them were normotensive and eleven hypertensive according to MetS threshold (≥130 mmHg for SBP and/or ≥85 mmHg for DBP). In the morning of 3 separated days, they underwent a cycling exercise bout of HIIT (>90% of maximal heart rate, ~85% VO 2max ), or a bout of isocaloric moderate-intensity continuous training (MICT; ~70% of maximal heart rate, ~60% VO 2max ), or a control no-exercise trial (REST). After exercise, ambulatory blood pressure (ABP; 14 h) was monitored, while subjects continued their habitual daily activities wearing a wrist-band activity monitor. No ABP differences were found for normotensive subjects. In hypertensive subjects, systolic ABP was reduced by 6.1 ± 2.2 mmHg after HIIT compared to MICT and REST (130.8 ± 3.9 vs. 137.4 ± 5.1 and 136.4 ± 3.8 mmHg, respectively; p < 0.05). However, diastolic ABP was similar in all three trials (77.2 ± 2.6 vs. 78.0 ± 2.6 and 78.9 ± 2.8 mmHg, respectively). Motion analysis revealed no differences among trials during the 14-h. This study suggests that the blood pressure reducing effect of a bout of exercise is influence by the intensity of exercise. A HIIT exercise bout is superior to an equivalent bout of continuous exercise when used as a non-pharmacological aid in the treatment of hypertension in MetS.

Quality assurance programs for pressure ulcers.

PubMed

Xakellis, G C

1997-08-01

Traditional medical quality assurance programs are beginning to incorporate the principles of continuous quality improvement pioneered by Juran and Deming. Strategies for incorporating these principles into a long-term care facility are described, and two examples of successful implementation of continuous quality improvement programs for pressure ulcers are presented.

49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120...

49 CFR 179.102 - Special commodity requirements for pressure tank car tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... car tanks. 179.102 Section 179.102 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120...

Continuous Measurement of Methane Ebullition Flux from a Northern Peatland using a Fast Methane Analyzer

NASA Astrophysics Data System (ADS)

Zhongjie, Y.; Schafer, K. V.; Slater, L. D.; Varner, R. K.; Amante, J.; Comas, X.; Reeve, A. S.; Alcivar, W.; Gonzalez, D.

2012-12-01

Northern peatlands are an important source of methane (CH4) release to the atmosphere, estimated at between 20 and 50 Tg/yr. Recent work on CH4 emissions from peatlands has demonstrated that ebullition can be a more important emission pathway than previously assumed. However, accurate quantification of the atmospheric CH4 burden due to ebullition is still very limited because ebullition exhibits high spatiotemporal variability such that sudden episodic events are difficult to capture and quantify with existing experimental methods. We have initiated a novel measurement program to better quantify the spatiotemporal variability in CH4 flux in peatlands, and to examine potential effects of vegetation and environmental factors, e.g. atmospheric pressure, water table, etc on these releases. A flow-through system was designed, consisting of a closed static chamber and a fast methane analyzer (FMA) (LI-COR model 7700) that has been employed at both the field and laboratory scale. The CH4 concentration in the air flowing through the chamber is continuously measured by the analyzer and used to reconstruct continuous CH4 emission fluxes. The high sampling rate of the FMA makes it sensitive to both ebullition and diffusion of gaseous CH4, capturing short duration, episodic ebullition fluxes. Non-steady static chamber measurements were also conducted to cross-validate the continuous measurements. Results acquired during summer 2011 show that episodic ebullition occurred more frequently at the pool site where previous studies indicate extensive wood layers at depth and the vegetation was a mix of Sphagnum and wooded heath. During a 3 day period of continuous measurements captured the passage of a tropical storm Irene, where short term episodic releases of CH4, ranging from 113 mg CH4/m2/d to 202 mg CH4/m2/d, were observed at the time of lowest atmospheric pressure, providing new evidence that atmospheric pressure is an important factor to controlling CH4 ebullition from peatlands. While traditional techniques, e.g. static chamber measurement can only occasionally detect the occurrence of ebullition, the continuous measurement by using a flow-through system is able to resolve spatiotemporal complexity of episodic CH4 ebullition events. These continuous CH4 measurements provide new insights into the timing of CH4 ebullition from peatlands to the atmosphere as climate changes and the role of environmental variables in regulating these CH4 releases.

Automatic blood pressure measuring system (M092)

NASA Technical Reports Server (NTRS)

Nolte, R. W.

1977-01-01

The Blood Pressure Measuring System is described. It measures blood pressure by the noninvasive Korotkoff sound technique on a continual basis as physical stress is imposed during experiment M092, Lower Body Negative Pressure, and experiment M171, Metabolic Activity.

The effects of finite rate chemical processes on high enthalpy nozzle performance - A comparison between SPARK and SEAGULL

NASA Technical Reports Server (NTRS)

Carpenter, M. H.

1988-01-01

The generalized chemistry version of the computer code SPARK is extended to include two higher-order numerical schemes, yielding fourth-order spatial accuracy for the inviscid terms. The new and old formulations are used to study the influences of finite rate chemical processes on nozzle performance. A determination is made of the computationally optimum reaction scheme for use in high-enthalpy nozzles. Finite rate calculations are compared with the frozen and equilibrium limits to assess the validity of each formulation. In addition, the finite rate SPARK results are compared with the constant ratio of specific heats (gamma) SEAGULL code, to determine its accuracy in variable gamma flow situations. Finally, the higher-order SPARK code is used to calculate nozzle flows having species stratification. Flame quenching occurs at low nozzle pressures, while for high pressures, significant burning continues in the nozzle.

Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating

NASA Astrophysics Data System (ADS)

Shen, X. F.; Qiao, B.; Zhang, H.; Kar, S.; Zhou, C. T.; Chang, H. X.; Borghesi, M.; He, X. T.

2017-05-01

A method to achieve stable radiation pressure acceleration (RPA) of heavy ions from laser-irradiated ultrathin foils is proposed, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating heavy ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as foil deformation and electron loss induced by the Rayleigh-Taylor-like and other instabilities in RPA are significantly offset and suppressed so that stable acceleration of heavy ions are maintained. Particle-in-cell simulations show that a monoenergetic Al13 + beam with peak energy 3.8 GeV and particle number 1 010 (charge >20 nC ) can be obtained at intensity 1 022 W /cm2 .

Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

NASA Technical Reports Server (NTRS)

Somsel, James P.

1998-01-01

The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

DOEpatents

Berry, G.F.; Minkov, V.; Petrick, M.

1981-11-02

A magnetohydrodynamic (MHD) power generating system is described in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.