Room-Temperature Pressure-Induced Optically-Actuated Fabry-Perot Nanomechanical Resonator with Multilayer Graphene Diaphragm in Air.

PubMed

Li, Cheng; Lan, Tian; Yu, Xiyu; Bo, Nan; Dong, Jingyu; Fan, Shangchun

2017-11-04

We demonstrated a miniature and in situ ~13-layer graphene nanomechanical resonator by utilizing a simple optical fiber Fabry-Perot (F-P) interferometric excitation and detection scheme. The graphene film was transferred onto the endface of a ferrule with a 125-μm inner diameter. In contrast to the pre-tension induced in membrane that increased quality ( Q ) factor to ~18.5 from ~3.23 at room temperature and normal pressure, the limited effects of air damping on resonance behaviors at 10 -2 and 10⁵ Pa were demonstrated by characterizing graphene F-P resonators with open and micro-air-gap cavities. Then in terms of optomechanical behaviors of the resonator with an air micro-cavity configuration using a polished ferrule substrate, measured resonance frequencies were increased to the range of 509-542 kHz from several kHz with a maximum Q factor of 16.6 despite the lower Knudsen number ranging from 0.0002 to 0.0006 in damping air over a relative pressure range of 0-199 kPa. However, there was the little dependence of Q on resonance frequency. Note that compared with the inferior F-P cavity length response to applied pressures due to interfacial air leakage, the developed F-P resonator exhibited a consistent fitted pressure sensitivity of 1.18 × 10⁵ kHz³/kPa with a good linearity error of 5.16% in the tested range. These measurements shed light on the pre-stress-dominated pressure-sensitive mechanisms behind air damping in in situ F-P resonant sensors using graphene or other 2D nanomaterials.

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure.

PubMed

Ran, Zengling; Liu, Shan; Liu, Qin; Huang, Ya; Bao, Haihong; Wang, Yanjun; Luo, Shucheng; Yang, Huiqin; Rao, Yunjiang

2014-08-07

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

Association between blood pressure changes during self-paced outdoor walking and air temperature.

PubMed

Otsuki, Takeshi; Ishii, Nanako

2017-03-01

Exaggerated elevation of systolic blood pressure (SBP) during exercise is a risk factor for future cardiovascular disease. Although there are differences between the outdoor exercise and exercise tests in the laboratory setting, there is little information regarding SBP changes during practical outdoor exercise. We investigated SBP changes during self-paced outdoor walking and the relationship to air temperature. Subjects (n = 109, 47-83 years) walked outdoors at their own pace wearing a blood pressure monitor on their wrist. SBP increased during walking compared to rest, but was higher at the 1 km mark than both the 2 and 3 km marks (rest, 124 ± 14 mmHg; 1 km, 140 ± 16 mmHg; 2 km, 136 ± 18 mmHg; 3 km, 135 ± 18 mmHg). SBP at rest, air temperature, body mass index (BMI) and walking intensity during the first 1 km were identified as predictors of SBP at the 1 km mark in the stepwise regression analysis, independent of other confounders (R 2  = 0·606). SBP at the 1 km mark was higher in the lower temperature group (11·6-14·3°C, 145 ± 14 mmHg) than in the intermediate (15·1-16·7°C, 140 ± 18 mmHg) and higher (17·0-19·6°C, 136 ± 16 mmHg) temperature groups, independent of SBP at rest, BMI and walking intensity. These results suggest that increases in SBP are higher on lower temperature days and are greater at 1 km than at 2 and 3 km. It is therefore recommended that measures are taken against the cold on lower temperature days to attenuate the SBP response during onset of walking. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

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

Yu, Shuang; Wang, Kaile; Zuo, Shasha

A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solutionmore » with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.« less

Investigation of X24C-2 10-Stage Axial-Flow Compressor. 2; Effect of Inlet-Air Pressure and Temperature of Performance

NASA Technical Reports Server (NTRS)

Finger, Harold B.; Schum, Harold J.; Buckner, Howard Jr.

1947-01-01

Effect of inlet-air pressure and temperature on the performance of the X24-2 10-Stage Axial-Flow Compressor from the X24C-2 turbojet engine was evaluated. Speeds of 80, 89, and 100 percent of equivalent design speed with inlet-air pressures of 6 and 12 inches of mercury absolute and inlet-air temperaures of approximately 538 degrees, 459 degrees,and 419 degrees R ( 79 degrees, 0 degrees, and minus 40 degrees F). Results were compared with prior investigations.

Effect of inlet-air humidity, temperature, pressure, and reference Mach number on the formation of oxides of nitrogen in a gas turbine combustor

NASA Technical Reports Server (NTRS)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

Tests were conducted to determine the effect of inlet air humidity on the formation of oxides of nitrogen (NOx) from a gas turbine combustor. Combustor inlet air temperature ranged from 506 K (450 F) to 838 K (1050 F). The tests were primarily run at a constant pressure of 6 atmospheres and reference Mach number of 0.065. The NOx emission index was found to decrease with increasing inlet air humidity at a constant exponential rate: NOx = NOx0e-19H (where H is the humidity and the subscript 0 denotes the value at zero humidity). the emission index increased exponentially with increasing normalized inlet air temperature to the 1.14 power. Additional tests made to determine the effect of pressure and reference Mach number on NOx showed that the NOx emission index varies directly with pressure to the 0.5 power and inversely with reference Mach number.

High-pressure combustor exhaust emissions with improved air-atomizing and conventional pressure-atomizing fuel nozzles

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1973-01-01

A high-pressure combustor segment 0.456 meter (18 in.) long with a maximum cross section of 0.153 by 0.305 meter (6 by 12 in.) was tested with specially designed air-atomizing and conventional pressure-atomizing fuel nozzles at inlet-air temperatures of 340 to 755 k (610 deg to 1360 R), reference velocities of 12.4 to 26.1 meters per second (41 to 86 ft/sec), and fuel-air ratios of 0.008 to 0.020. Increasing inlet-air pressure from 4 to 20 atmospheres generally increased smoke number and nitric oxide, but decreased carbon monoxide and unburned hydrocarbon concentrations with air-atomizing and pressure-atomizing nozzles. Emission indexes for carbon monoxide and unburned hydrocarbons were lower at 4, 10, and 20 atmospheres, and nitric oxide emission indexes were lower at 10 and 20 atmospheres with air-atomizing than with pressure-atomizing nozzles.

Comparison of Calculated and Experimental Temperatures and Coolant Pressure Losses for a Cascade of Small Air-Cooled Turbine Rotor Blades

NASA Technical Reports Server (NTRS)

Stepka, Francis S

1958-01-01

Average spanwise blade temperatures and cooling-air pressure losses through a small (1.4-in, span, 0.7-in, chord) air-cooled turbine blade were calculated and are compared with experimental nonrotating cascade data. Two methods of calculating the blade spanwise metal temperature distributions are presented. The method which considered the effect of the length-to-diameter ratio of the coolant passage on the blade-to-coolant heat-transfer coefficient and assumed constant coolant properties based on the coolant bulk temperature gave the best agreement with experimental data. The agreement obtained was within 3 percent at the midspan and tip regions of the blade. At the root region of the blade, the agreement was within 3 percent for coolant flows within the turbulent flow regime and within 10 percent for coolant flows in the laminar regime. The calculated and measured cooling-air pressure losses through the blade agreed within 5 percent. Calculated spanwise blade temperatures for assumed turboprop engine operating conditions of 2000 F turbine-inlet gas temperature and flight conditions of 300 knots at a 30,000-foot altitude agreed well with those obtained by the extrapolation of correlated experimental data of a static cascade investigation of these blades.

Influence of fuel temperature on atomization performance of pressure-swirl atomizers

NASA Astrophysics Data System (ADS)

Wang, X. F.; Lefebvre, A. H.

The influence of fuel temperature on mean drop size and drop-size distribution is examined for aviation gasoline and diesel oil, using three pressure-swirl simplex nozzles. Spray characteristics are measured over wide ranges of fuel injection pressure and ambient air pressure using a Malvern spray analyzer. Fuel temperatures are varied from -20 C to +50 C. Over this range of temperature, the overall effect of an increase in fuel temperature is to reduce the mean drop size and broaden the distribution of drop sizes in the spray. Generally, it is found that the influence of fuel temperature on mean drop size is far more pronounced for diesel oil than for gasoline. For both fuels the beneficial effect of higher fuel temperatures on atomization quality is sensibly independent of ambient air pressure.

Apparatus and method for maintaining an article at a temperature that is less than the temperature of the ambient air

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

Klett, James; Klett, Lynn

An apparatus for maintaining the temperature of an article at a temperature that is below the ambient air temperature includes an enclosure having an outer wall that defines an interior chamber for holding a volume of sealed air. An insert is disposed inside of the chamber and has a body that is made of a porous graphite foam material. A vacuum pump penetrates the outer wall and fluidly connects the sealed air in the interior chamber with the ambient air outside of the enclosure. The temperatures of the insert and article is maintained at temperatures that are below the ambientmore » air temperature when a volume of a liquid is wicked into the pores of the porous insert and the vacuum pump is activated to reduce the pressure of a volume of sealed air within the interior chamber to a pressure that is below the vapor pressure of the liquid.« less

Do sudden air temperature and pressure changes affect cardiovascular morbidity and mortality?

NASA Astrophysics Data System (ADS)

Plavcová, E.; Davídkovová, H.; Kyselý, J.

2012-04-01

Previous studies have shown that sudden changes in weather (usually represented by air temperature and/or pressure) are associated with increases in daily mortality. Little is understood about physiological mechanisms responsible for the impacts of weather changes on mortality, and whether similar patterns appear for morbidity as well. Relatively little is known also about differences in the magnitude of the mortality response in provincial regions and in cities, where the impacts may be exacerbated by air pollution effects and/or heat island. The present study examines the effects of sudden air temperature and pressure changes on morbidity (represented by hospital admissions) and mortality due to cardiovascular diseases in the population of the Czech Republic (approx. 10 million inhabitants) and separately in the city of Prague (1.2 million inhabitants). The events are selected from data covering 1994-2009 using the methodology introduced by Plavcová and Kyselý (2010), and they are compared with the datasets on hospital admissions and daily mortality (both standardized to account for long-term changes and the seasonal and weekly cycles). Relative deviations of morbidity/mortality from the baseline were averaged over the selected events for days D-2 (2 days before a change) up to D+7 (7 days after), and their statistical significance was tested by means of the Monte Carlo method. The study aims at (i) identifying those weather changes associated with increased cardiovascular morbidity/mortality, separately in summer and winter, (ii) comparing the effects of weather changes on morbidity and mortality, (iii) identifying whether urban population of Prague is more/less vulnerable in comparison to the population of the whole Czech Republic, (iv) comparing the effects for different cardiovascular diseases (ischaemic heart diseases, ICD-10 codes I20-I25; cerebrovascular diseases, I60-I69; hypertension, I10; atherosclerosis, I70) and individual population groups (by age

The role of photoionization in negative corona discharge: The influences of temperature, humidity, and air pressure on a corona

NASA Astrophysics Data System (ADS)

Sun, H. Y.; Lu, B. X.; Wang, M.; Guo, Q. F.; Feng, Q. K.

2017-10-01

The swarm parameters of the negative corona discharge are improved to calculate the discharge model under different environmental conditions. The effects of temperature, humidity, and air pressure are studied using a conventional needle-to-plane configuration in air. The electron density, electric field, electron generation rate, and photoelectron generation rate are discussed in this paper. The role of photoionization under these conditions is also studied by numerical simulation. The photoelectrons generated in weak ionization region are proved to be dominant.

Liquid Jets in Crossflow at Elevated Temperatures and Pressures

NASA Astrophysics Data System (ADS)

Amighi, Amirreza

An experimental study on the characterization of liquid jets injected into subsonic air crossflows is conducted. The aim of the study is to relate the droplet size and other attributes of the spray, such as breakup length, position, plume width, and time to flow parameters, including jet and air velocities, pressure and temperature as well as non-dimensional variables. Furthermore, multiple expressions are defined that would summarize the general behavior of the spray. For this purpose, an experimental setup is developed, which could withstand high temperatures and pressures to simulate conditions close to those experienced inside gas turbine engines. Images are captured using a laser based shadowgraphy system similar to a 2D PIV system. Image processing is extensively used to measure droplet size and boundaries of the spray. In total 209 different conditions are tested and over 72,000 images are captured and processed. The crossflow air temperatures are 25°C, 200°C, and 300°C; absolute crossflow air pressures are 2.1, 3.8, and 5.2 bars. Various liquid and gas velocities are tested for each given temperature and pressure in order to study the breakup mechanisms and regimes. Effects of dimensional and non-dimensional variables on droplet size are presented in detail. Several correlations for the mean droplet size, which are generated in this process, are presented. In addition, the influence of non-dimensional variables on the breakup length, time, plume area, angle, width and mean jet surface thickness are discussed and individual correlations are provided for each parameter. The influence of each individual parameter on the droplet sizes is discussed for a better understanding of the fragmentation process. Finally, new correlations for the centerline, windward and leeward trajectories are presented and compared to the previously reported correlations.

Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

1939-01-01

Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

Air Circulation and Heat Exchange under Reduced Pressures

NASA Astrophysics Data System (ADS)

Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

Low pressure atmospheres were suggested for Space Greenhouses (SG) design to minimize sys-tem construction and re-supply materials, as well as system manufacturing and deployment costs. But rarified atmospheres modify heat exchange mechanisms what finally leads to alter-ations in thermal control for low pressure closed environments. Under low atmospheric pressures (e.g., lower than 25 kPa compare to 101.3 kPa for normal Earth atmosphere), convection is becoming replaced by diffusion and rate of heat exchange reduces significantly. During a period from 2001 to 2009, a series of hypobaric experiments were conducted at Space Life Sciences Lab (SLSLab) NASA's Kennedy Space Center and the Department of Space Studies, University of North Dakota. Findings from these experiments showed: -air circulation rate decreases non-linearly with lowering of total atmospheric pressure; -heat exchange slows down with pressure decrease creating risk of thermal stress (elevated leaf tem-peratures) for plants in closed environments; -low pressure-induced thermal stress could be reduced by either lowering system temperature set point or increasing forced convection rates (circulation fan power) within certain limits; Air circulation is an important constituent of controlled environments and plays crucial role in material and heat exchange. Theoretical schematics and mathematical models are developed from a series of observations. These models can be used to establish optimal control algorithms for low pressure environments, such as a space greenhouse, as well as assist in fundamental design concept developments for these or similar habitable structures.

Investigation of the spatial variability and possible origins of wind-induced air pressure fluctuations responsible for pressure pumping

NASA Astrophysics Data System (ADS)

Mohr, Manuel; Laemmel, Thomas; Maier, Martin; Zeeman, Matthias; Longdoz, Bernard; Schindler, Dirk

2017-04-01

The exchange of greenhouse gases between the soil and the atmosphere is highly relevant for the climate of the Earth. Recent research suggests that wind-induced air pressure fluctuations can alter the soil gas transport and therefore soil gas efflux significantly. Using a newly developed method, we measured soil gas transport in situ in a well aerated forest soil. Results from these measurements showed that the commonly used soil gas diffusion coefficient is enhanced up to 30% during periods of strong wind-induced air pressure fluctuations. The air pressure fluctuations above the forest floor are only induced at high above-canopy wind speeds (> 5 m s-1) and lie in the frequency range 0.01-0.1 Hz. Moreover, the amplitudes of air pressure fluctuations in this frequency range show a clear quadratic dependence on mean above-canopy wind speed. However, the origin of these wind-induced pressure fluctuations is still unclear. Airflow measurements and high-precision air pressure measurements were conducted at three different vegetation-covered sites (conifer forest, deciduous forest, grassland) to investigate the spatial variability of dominant air pressure fluctuations, their origin and vegetation-dependent characteristics. At the conifer forest site, a vertical profile of air pressure fluctuations was measured and an array consisting of five pressure sensors were installed at the forest floor. At the grassland site, the air pressure measurements were compared with wind observations made by ground-based LIDAR and spatial temperature observations from a fibre-optic sensing network (ScaleX Campaign 2016). Preliminary results show that at all sites the amplitudes of relevant air pressure fluctuations increase with increasing wind speed. Data from the array measurements reveal that there are no time lags between the air pressure signals of different heights, but a time lag existed between the air pressure signals of the sensors distributed laterally on the forest floor

Air-braked cycle ergometers: validity of the correction factor for barometric pressure.

PubMed

Finn, J P; Maxwell, B F; Withers, R T

2000-10-01

Barometric pressure exerts by far the greatest influence of the three environmental factors (barometric pressure, temperature and humidity) on power outputs from air-braked ergometers. The barometric pressure correction factor for power outputs from air-braked ergometers is in widespread use but apparently has never been empirically validated. Our experiment validated this correction factor by calibrating two air-braked cycle ergometers in a hypobaric chamber using a dynamic calibration rig. The results showed that if the power output correction for changes in air resistance at barometric pressures corresponding to altitudes of 38, 600, 1,200 and 1,800 m above mean sea level were applied, then the coefficients of variation were 0.8-1.9% over the range of 160-1,597 W. The overall mean error was 3.0 % but this included up to 0.73 % for the propagated error that was associated with errors in the measurement of: a) temperature b) relative humidity c) barometric pressure d) force, distance and angular velocity by the dynamic calibration rig. The overall mean error therefore approximated the +/- 2.0% of true load that was specified by the Laboratory Standards Assistance Scheme of the Australian Sports Commission. The validity of the correction factor for barometric pressure on power output was therefore demonstrated over the altitude range of 38-1,800 m.

Complete temperature profiles in ultra-high-pressure liquid chromatography columns.

PubMed

Gritti, Fabrice; Guiochon, Georges

2008-07-01

The temperature profiles were calculated along and across seven packed columns (lengths 30, 50, 100, and 150 mm, i.d., 1 and 2.1 mm, all packed with Acquity UPLC, BEH-C 18 particles, average d(p) approximately 1.7 microm) and their stainless steel tubes (o.d. 4.53 and 6.35 mm). These columns were kept horizontal and sheltered from forced air convection (i.e., under still air conditions), at room temperature. They were all percolated with pure acetonitrile, either under the maximum pressure drop (1034 bar) or at the maximum flow rate (2 mL/min) permitted by the chromatograph. The heat balance equation of chromatographic columns was discretized and solved numerically with minimum approximation. Both the compressibility and the thermal expansion of the eluent were taken into account. The boundary conditions were determined from the experimental measurements of the column inlet pressure and of the temperature profile along the column wall, which were made with a precision better than +/-0.1 K. These calculation results provide the 3-D temperature profiles along and across the columns. The axial and radial temperature gradients are discussed in relationship with the experimental conditions used. The temperature map obtained permits a prediction of the chromatographic data obtained under a very high pressure gradient.

Inverse Association between Air Pressure and Rheumatoid Arthritis Synovitis

PubMed Central

Furu, Moritoshi; Nakabo, Shuichiro; Ohmura, Koichiro; Nakashima, Ran; Imura, Yoshitaka; Yukawa, Naoichiro; Yoshifuji, Hajime; Matsuda, Fumihiko; Ito, Hiromu; Fujii, Takao; Mimori, Tsuneyo

2014-01-01

Rheumatoid arthritis (RA) is a bone destructive autoimmune disease. Many patients with RA recognize fluctuations of their joint synovitis according to changes of air pressure, but the correlations between them have never been addressed in large-scale association studies. To address this point we recruited large-scale assessments of RA activity in a Japanese population, and performed an association analysis. Here, a total of 23,064 assessments of RA activity from 2,131 patients were obtained from the KURAMA (Kyoto University Rheumatoid Arthritis Management Alliance) database. Detailed correlations between air pressure and joint swelling or tenderness were analyzed separately for each of the 326 patients with more than 20 assessments to regulate intra-patient correlations. Association studies were also performed for seven consecutive days to identify the strongest correlations. Standardized multiple linear regression analysis was performed to evaluate independent influences from other meteorological factors. As a result, components of composite measures for RA disease activity revealed suggestive negative associations with air pressure. The 326 patients displayed significant negative mean correlations between air pressure and swellings or the sum of swellings and tenderness (p = 0.00068 and 0.00011, respectively). Among the seven consecutive days, the most significant mean negative correlations were observed for air pressure three days before evaluations of RA synovitis (p = 1.7×10−7, 0.00027, and 8.3×10−8, for swellings, tenderness and the sum of them, respectively). Standardized multiple linear regression analysis revealed these associations were independent from humidity and temperature. Our findings suggest that air pressure is inversely associated with synovitis in patients with RA. PMID:24454853

The association of air temperature with cardiac arrhythmias

NASA Astrophysics Data System (ADS)

Čulić, Viktor

2017-11-01

The body response to meteorological influences may activate pathophysiological mechanisms facilitating the occurrence of cardiac arrhythmias in susceptible patients. Putative underlying mechanisms include changes in systemic vascular resistance and blood pressure, as well as a network of proinflammatory and procoagulant processes. Such a chain reaction probably occurs within the time window of several hours, so use of daily average values of meteorological elements do not seem appropriate for investigation in this area. In addition, overall synoptic situation, and season-specific combinations of meteorological elements and air pollutant levels probably cause the overall effect rather than a single atmospheric element. Particularly strong interrelations have been described among wind speed, air pressure and temperature, relative air humidity, and suspended particulate matter. This may be the main reason why studies examining the association between temperature and ventricular arrhythmias have found linear positive, negative, J-shaped or no association. Further understanding of the pathophysiological adaptation to atmospheric environment may help in providing recommendations for protective measures during "bad" weather conditions in patients with cardiac arrhythmias.

Effects of open-air temperature on air temperature inside biological safety cabinet.

PubMed

Umemura, Masayuki; Shigeno, Katsuro; Yamamura, Keiko; Osada, Takashi; Soda, Midori; Yamada, Kiyofumi; Ando, Yuichi; Wakiya, Yoshifumi

2011-02-14

In Japan, biological safety cabinets (BSCs) are normally used by medical staff while handling antineoplastic agents. We have also set up a class II B2 BSC at the Division of Chemotherapy for Outpatients. The air temperature inside this BSC, however, decreases in winter. We assumed that this decrease is caused by the intake of open-air. Therefore, we investigated the effects of low open-air temperature on the BSC temperature and the time of admixtures of antineoplastic agents. The studies were conducted from January 1 to March 31, 2008. The outdoor air temperature was measured in the shade near the intake nozzle of the BSC and was compared with the BSC temperature. The correlation between the outdoor air temperature and the BSC temperature, the dissolution time of cyclophosphamide (CPA) and gemcitabine (GEM), and accurate weight measurement of epirubicin (EPI) solution were investigated for low and normal BSC temperatures. The BSC temperature was correlated with the open-air temperature for open-air temperatures of 5-20°C (p < 0.0001). The dissolution of CPA and GEM at these temperatures was significantly delayed as compared to that at 25°C (p < 0.01 and p < 0.0001, respectively). The weight measurement of EPI solution using a syringe method lacks accuracy because of its high coefficient of viscosity at low temperatures (p < 0.01). These results suggest that the BSC temperature decreases below room temperature in winter when air is drawn from outdoors. We showed that the BSC temperature affects the dissolution rate of antineoplastic agents. Further, we suggested that the BSC temperature drop might delay the affair of the admixtures of antineoplastic agents and increase the waiting time of outpatients for chemotherapy.

Alterations in MAST suit pressure with changes in ambient temperature.

PubMed

Sanders, A B; Meislin, H W; Daub, E

1983-01-01

A study was undertaken to test the hypothesis that change in ambient air temperature has an effect on MAST suit pressure according to the ideal gas law. Two different MAST suits were tested on Resusci-Annie dummies. The MAST suits were applied in a cold room at 4.4 degrees C and warmed to 44 degrees C. Positive linear correlations were found in nine trials, but the two suits differed in their rate of increase in pressure. Three trials using humans were conducted showing increased pressure with temperature but at a lesser rate than with dummies. A correlation of 0.5 to 1.0 mm Hg increase in MAST suit pressure for each 1.0 degrees C increase in ambient temperature was found. Implications are discussed for the use of the MAST suit in environmental conditions where the temperature changes.

Temperature dependence of Lorentz air-broadening and pressure-shift coefficients of (12)CH4 lines in the 2.3-micron spectral region

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Rinsland, C. P.

1994-01-01

High-resolution (0.01/cm) absorption spectra of lean mixtures of CH4 in dry air were recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak at various temperatures between 24 and -61 C. The spectra have been analyzed to determine the values at room temperature of pressure-broadened widths and pressure-induced shifts of more than 740 transitions. The temperature dependence of air-broadened widths and pressure-induced shifts was deduced for approx. 370 transitions in the nu(sub 1) + nu(sub 4), nu(sub 3) + nu(sub 4), and nu(sub 2) + nu(sub 3) bands of (12)CH4 located between 4118 and 4615/cm. These results were obtained by analyzing a total of 29 spectra simultaneously using a multi-spectral non-linear least-squares fitting technique. This new technique allowed the determination of correlated spectral line parameters (e.g. intensity and broadening coefficient) better than the procedure of averaging values obtained by fitting the spectra individually. This method also provided a direct determination of the uncertainties in the retrieved parameters due to random errors. For each band analysed in this study the dependence of the various spectral line parameters upon the tetrahedral symmetry species and the rotational quantum numbers of the transitions is also presented.

Synthesis of ammonia directly from air and water at ambient temperature and pressure

NASA Astrophysics Data System (ADS)

Lan, Rong; Irvine, John T. S.; Tao, Shanwen

2013-01-01

The N≡N bond (225 kcal mol-1) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N2 separation and H2 production stages. A maximum ammonia production rate of 1.14 × 10-5 mol m-2 s-1 has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

Synthesis of ammonia directly from air and water at ambient temperature and pressure

PubMed Central

Lan, Rong; Irvine, John T. S.; Tao, Shanwen

2013-01-01

The N≡N bond (225 kcal mol−1) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N2 separation and H2 production stages. A maximum ammonia production rate of 1.14 × 10−5 mol m−2 s−1 has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future. PMID:23362454

Synthesis of ammonia directly from air and water at ambient temperature and pressure.

PubMed

Lan, Rong; Irvine, John T S; Tao, Shanwen

2013-01-01

The N≡N bond (225 kcal mol⁻¹) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N₂ separation and H₂ production stages. A maximum ammonia production rate of 1.14 × 10⁻⁵ mol m⁻² s⁻¹ has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

Differential absorption lidar measurements of atmospheric temperature and pressure profiles

NASA Technical Reports Server (NTRS)

Korb, C. L.

1981-01-01

The theory and methodology of using differential absorption lidar techniques for the remote measurement of atmospheric pressure profiles, surface pressure, and temperature profiles from ground, air, and space-based platforms are presented. Pressure measurements are effected by means of high resolution measurement of absorption at the edges of the oxygen A band lines where absorption is pressure dependent due to collisional line broadening. Temperature is assessed using measurements of the absorption at the center of the oxygen A band line originating from a quantum state with high ground state energy. The population of the state is temperature dependent, allowing determination of the temperature through the Boltzmann term. The results of simulations of the techniques using Voigt profile and variational analysis are reported for ground-based, airborne, and Shuttle-based systems. Accuracies in the 0.5-1.0 K and 0.1-0.3% range are projected.

Are there evidences of altitudinal effects of air temperature trends in the European Alps 1820-2013?

NASA Astrophysics Data System (ADS)

Schoener, W.; Auer, I.; Chimani, B.; Garnekind, M.; Haslinger, K.

2013-12-01

We use the HISTALP data set (www.zamg.ac.at/histalp) in order to assess the elevation dependency of air temperature trends within the European Alps. The evidence of altitudinal effects of the climate warming (with higher sensitivity of high mountain regions to warming) is a key statement, or at least key hypothesis, in many studies. The high relevance of such statement resp. hypothesis is obvious if one consider the impacts resulting from such fact, such as snow- and glacier melting and related effects for mountain hydrology. The HISTALP data set stands out with respect to its series lengths and its high level of homogenisation. Interestingly, the HISTALP temperature data show no clear altitudinal dependency of warming or cooling trends within the period 1820-2013. Additionally, a rather homogenous temporal trend could be observed within the entire Greater Alpine Region (GAR). Because HISTALP include also air pressure and vapour pressure series, we could compare our measured air temperatures with mean-column air temperatures, computed by the barometric formula, which were derived from the independently measured air pressure data (using vapour pressure to account for the atmospheric water content) at low resp. high elevations. Computed mean column temperatures are in good agreement with observed temperatures, indicating generally homogenous temporal temperature trend behaviour at different elevations. Our finding contradicts several results from climate modelling attempts and also other studies investigating Alpine temperature trends. We conclude that, whereas modelling results are still limited in the assessment of altitudinal effect of temperature trends from missing atmospheric processes captured by the models, the difference of the trend behaviour compared to other analyses of instrumental air temperatures comes from the seasonal base taken as the basis for trend estimation. It appears that opposite trend in spring and autumn for the period 1980

Spectroscopic temperature measurements of air breakdown plasma using a 110 GHz megawatt gyrotron beam

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

Hummelt, J. S.; Shapiro, M. A.; Temkin, R. J.

2012-12-15

Temperature measurements are presented of a non-equilibrium air breakdown plasma using optical emission spectroscopy. A plasma is created with a focused 110 GHz 3 {mu}s pulse gyrotron beam in air that produces power fluxes exceeding 1 MW/cm{sup 2}. Rotational and vibrational temperatures are spectroscopically measured over a pressure range of 1-100 Torr as the gyrotron power is varied above threshold. The temperature dependence on microwave field as well as pressure is examined. Rotational temperature measurements of the plasma reveal gas temperatures in the range of 300-500 K and vibrational temperatures in the range of 4200-6200 K. The vibrational and rotationalmore » temperatures increase slowly with increasing applied microwave field over the range of microwave fields investigated.« less

Crowdsourcing urban air temperatures from smartphone battery temperatures

NASA Astrophysics Data System (ADS)

Overeem, Aart; Robinson, James C. R.; Leijnse, Hidde; Steeneveld, Gert-Jan; Horn, Berthold K. P.; Uijlenhoet, Remko

2014-05-01

Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. It has been shown that a straightforward heat transfer model can be employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. The methodology has been applied to Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree

Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner.

PubMed

Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

2011-01-15

Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor. Copyright © 2010 Elsevier B.V. All rights reserved.

High Temperature Ceramic Guide Vane Temperature and Pressure Distribution Calculation for Flow with Cooling Jets

NASA Technical Reports Server (NTRS)

Srivastava, Rakesh

2004-01-01

A ceramic guide vane has been designed and tested for operation under high temperature. Previous efforts have suggested that some cooling flow may be required to alleviate the high temperatures observed near the trailing edge region. The present report describes briefly a three-dimensional viscous analysis carried out to calculate the temperature and pressure distribution on the blade surface and in the flow path with a jet of cooling air exiting from the suction surface near the trailing edge region. The data for analysis was obtained from Dr. Craig Robinson. The surface temperature and pressure distribution along with a flowfield distribution is shown in the results. The surface distribution is also given in a tabular form at the end of the document.

Laser plasma at low air pressure

NASA Astrophysics Data System (ADS)

Vas'kovskii, Iu. M.; Moiseev, V. N.; Rovinskii, R. E.; Tsenina, I. S.

1993-01-01

The ambient-pressure dependences of the dynamic and optical characteristics of a laser plasma generated by CO2-laser irradiation of an obstacle are investigated experimentally. The change of the sample's surface roughness after irradiation is investigated as a function of air pressure. It is concluded that the transition from the air plasma to the erosion plasma takes place at an air pressure of about 1 mm Hg. The results confirm the existing theory of plasma formation near the surface of an obstacle under the CO2-laser pulse effect in air.

Laser-based air data system for aircraft control using Raman and elastic backscatter for the measurement of temperature, density, pressure, moisture, and particle backscatter coefficient.

PubMed

Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

2012-01-10

Flight safety in all weather conditions demands exact and reliable determination of flight-critical air parameters. Air speed, temperature, density, and pressure are essential for aircraft control. Conventional air data systems can be impacted by probe failure caused by mechanical damage from hail, volcanic ash, and icing. While optical air speed measurement methods have been discussed elsewhere, in this paper, a new concept for optically measuring the air temperature, density, pressure, moisture, and particle backscatter is presented, being independent on assumptions on the atmospheric state and eliminating the drawbacks of conventional aircraft probes by providing a different measurement principle. The concept is based on a laser emitting laser pulses into the atmosphere through a window and detecting the signals backscattered from a fixed region just outside the disturbed area of the fuselage flows. With four receiver channels, different spectral portions of the backscattered light are extracted. The measurement principle of air temperature and density is based on extracting two signals out of the rotational Raman (RR) backscatter signal of air molecules. For measuring the water vapor mixing ratio-and thus the density of the moist air-a water vapor Raman channel is included. The fourth channel serves to detect the elastic backscatter signal, which is essential for extending the measurements into clouds. This channel contributes to the detection of aerosols, which is interesting for developing a future volcanic ash warning system for aircraft. Detailed and realistic optimization and performance calculations have been performed based on the parameters of a first prototype of such a measurement system. The impact and correction of systematic error sources, such as solar background at daytime and elastic signal cross talk appearing in optically dense clouds, have been investigated. The results of the simulations show the high potential of the proposed system for

Investigation of air solubility in jet A fuel at high pressures

NASA Technical Reports Server (NTRS)

Rupprecht, S. D.; Faeth, G. M.

1981-01-01

The solubility and density properties of saturated mixtures of fuels and gases were measured. The fuels consisted of Jet A and dodecane, the gases were air and nitrogen. The test range included pressures of 1.03 to 10.34 MPa and temperatures of 298 to 373 K. The results were correlated successfully, using the Soave equation of state. Over this test range, dissolved gas concentrations were roughly proportional to pressure and increased slightly with increasing temperature. Mixture density was relatively independent of dissolved gas concentration.

High-temperature microphone system. [for measuring pressure fluctuations in gases at high temperature

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J. (Inventor)

1979-01-01

Pressure fluctuations in air or other gases in an area of elevated temperature are measured using a condenser microphone located in the area of elevated temperature and electronics for processing changes in the microphone capacitance located outside the area the area and connected to the microphone by means of high-temperature cable assembly. The microphone includes apparatus for decreasing the undesirable change in microphone sensitivity at high temperatures. The high temperature cable assembly operates as a half-wavelength transmission line in an AM carrier system and maintains a large temperature gradient between the two ends of the cable assembly. The processing electronics utilizes a voltage controlled oscillator for automatic tuning thereby increasing the sensitivity of the measuring apparatus.

Formaldehyde preparation methods for pressure and temperature dependent laser-induced fluorescence measurements

NASA Astrophysics Data System (ADS)

Burkert, A.; Müller, D.; Rieger, S.; Schmidl, G.; Triebel, W.; Paa, W.

2015-12-01

Formaldehyde is an excellent tracer for the early phase of ignition of hydrocarbon fuels and can be used, e.g., for characterization of single droplet ignition. However, due to its fast thermal decomposition at elevated temperatures and pressures, the determination of concentration fields from laser-induced fluorescence (LIF) measurements is difficult. In this paper, we address LIF measurements of this important combustion intermediate using a calibration cell. Here, formaldehyde is created from evaporation of paraformaldehyde. We discuss three setups for preparation of formaldehyde/air mixtures with respect to their usability for well-defined heating of formaldehyde/air mixtures. The "basic setup" uses a resist heater around the measurement cell for investigation of formaldehyde near vacuum conditions or formaldehyde/air samples after sequential admixing of air. The second setup, described for the first time in detail here, takes advantage of a constant flow formaldehyde/air regime which uses preheated air to reduce the necessary time for gas heating. We used the constant flow system to measure new pressure dependent LIF excitation spectra in the 343 nm spectral region (414 absorption band of formaldehyde). The third setup, based on a novel concept for fast gas heating via excitation of SF6 (chemically inert gas) using a TEA (transverse excitation at atmospheric pressure) CO2 laser, allows to further minimize both gas heating time and thermal decomposition. Here, an admixture of CO2 is served for real time temperature measurement based on Raman scattering. The applicability of the fast laser heating system has been demonstrated with gas mixtures of SF6 + air, SF6 + N2, as well as SF6 + N2 + CO2 at 1 bar total pressure.

Heat transfer and pressure drop measurements in an air/molten salt direct-contact heat exchanger

NASA Astrophysics Data System (ADS)

Bohn, Mark S.

1988-11-01

This paper presents a comparison of experimental data with a recently published model of heat exchange in irrigated packed beds. Heat transfer and pressure drop were measured in a 150 mm (ID) column with a 610 mm bed of metal Pall rings. Molten nitrate salt and preheated air were the working fluids with a salt inlet temperature of approximately 440 C and air inlet temperatures of approximately 230 C. A comparison between the experimental data and the heat transfer model is made on the basis of heat transfer from the salt. For the range of air and salt flow rates tested, 0.3 to 1.2 kg/sq m/s air flow and 6 to 18 kg/sq m/s salt flow, the data agree with the model within 22 percent standard deviation. In addition, a model for the column pressure drop was validated, agreeing with the experimental data within 18 percent standard deviation over the range of column pressure drop from 40 to 1250 Pa/m.

Particulate matter air pollution and ambient temperature: opposing effects on blood pressure in high-risk cardiac patients.

PubMed

Giorgini, Paolo; Rubenfire, Melvyn; Das, Ritabrata; Gracik, Theresa; Wang, Lu; Morishita, Masako; Bard, Robert L; Jackson, Elizabeth A; Fitzner, Craig A; Ferri, Claudio; Brook, Robert D

2015-10-01

Fine particulate matter air pollution (PM2.5) and extreme temperatures have both been associated with alterations in blood pressure (BP). However, few studies have evaluated their joint haemodynamic actions among individuals at high risk for cardiovascular events. We assessed the effects of short-term exposures during the prior week to ambient PM2.5 and outdoor temperature levels on resting seated BP among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from 2003 to 2011) using multiple linear regression analyses adjusting for age, sex, BMI, ozone and the same-day alternate environmental factor (i.e. PM2.5 or temperature). Mean PM2.5 and temperature levels were 12.6 ± 8.2 μg/m and 10.3 ± 10.4°C, respectively. Each standard deviation elevation in PM2.5 concentration during lag days 4-6 was associated with significant increases in SBP (2.1-3.5 mmHg) and DBP (1.7-1.8 mmHg). Conversely, higher temperature levels (per 10.4°C) during lag days 4-6 were associated with reductions in both SBP (-3.6 to -2.3 mmHg) and DBP (-2.5 to -1.8 mmHg). There was little evidence for consistent effect modification by other covariates (e.g. demographics, seasons, medication usage). Short-term exposures to PM2.5, even at low concentrations within current air quality standards, are associated with significant increases in BP. Contrarily, higher ambient temperatures prompt the opposite haemodynamic effect. These findings demonstrate that both ubiquitous environmental exposures have clinically meaningful effects on resting BP among high-risk cardiac patients.

Effects of Temperature and Air Density Profiles on Ozone Lidar Retrievals

NASA Astrophysics Data System (ADS)

Kirgis, G.; Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II

2017-12-01

The recent reduction in the primary U.S. National Ambient Air Quality Standard (NAAQS) for ozone (O3) from 75 to 70 parts-per-billion by volume (ppbv) adds urgency to the need for better understanding of the processes that control ground-level concentrations in the United States. While ground-based in situ sensors are capable of measuring ozone levels, they don't give any insight into upper air transport and mixing. Differential absorption lidars such as the NOAA/ESRL Tunable Optical Profiler for Aerosol and oZone (TOPAZ) measure continuous vertical ozone profiles with high spatial and temporal resolution. However, the retrieved ozone mixing ratios depend on the temperature and air density profiles used in the analysis. This study analyzes the ozone concentrations for seven field campaigns from 2013 to 2016 to evaluate the impact of the assumed pressure and temperature profiles on the ozone mixing ratio retrieval. Pressure and temperature profiles from various spatial and temporal resolution models (Modern Era Retrospective-Analysis for Research and Applications, NCEP/NCAR Reanalysis, NCEP North American Regional Reanalysis, Rapid Refresh, and High-Resolution Rapid Refresh) are compared to reference ozone profiles created with pressure and temperature profiles from ozonesondes launched close to the TOPAZ measurement site. The results show significant biases with respect to time of day and season, altitude, and location of the model-extracted profiles. Limitations and advantages of all datasets used will also be discussed.

The ignition delay times of hydrogen/silan/air mixtures at low temperatures

NASA Astrophysics Data System (ADS)

Tropin, D. A.; Bochenkov, E. S.; Fedorov, A. V.

2018-03-01

In the paper the ignition delay times of hydrogen-silane-air mixtures at low pressures from 0.4 atm to 1 atm and mixture temperatures from 300 K to 900 K using the detailed kinetic mechanisms were calculated. It was shown that dependencies of ignition delay time on temperature are non-monotonic. In these dependences a region of "negative temperature coefficient" is presented. The effect of the mixture pressure and the silane concentration in the mixture on the length of this region was revealed. It was shown that the increasing of the silane concentration in the mixture, as well as the increasing the mixture pressure, leads to increasing of the "negative temperature coefficient" region length.

Intraoral Air Pressure of Alaryngeal Speakers during a No-Air Insufflation Maneuver.

ERIC Educational Resources Information Center

Gorham, Mary M.; And Others

1996-01-01

Intraoral air pressure was recorded during the production of consonant cognate pairs by 8 esophageal speakers (mean age 67 years) under 2 experimental conditions: after the insufflation of air and without air insufflation. Results revealed that peak intraoral air pressure magnitudes were significantly greater following the insufflation of air than…

HYDROSTATIC PRESSURE AND TEMPERATURE IN RELATION TO STIMULATION AND CYCLOSIS IN NITELLA FLEXILIS

PubMed Central

Harvey, E. Newton

1942-01-01

Nitella flexilis cells are not stimulated to "shock stoppage" of cyclosis by suddenly evacuating the air over the water or on sudden readmission of air, or on suddenly striking a piston in the water-filled chamber in which they are kept with a ball whose energy is 7.6 joules, provided the Nitella cell is not moved by currents against the side of the chamber. Sudden increases in hydrostatic pressure from zero to 1000 lbs. or 0 to 5000 lbs. per square inch or 5000 to 9000 lbs. per square inch usually do not stimulate to "shock stoppage" of cyclosis, but some cells are stimulated. Sudden decreases of pressure are more likely to stimulate, again with variation depending on the cell. In the absence of stimulation, the cyclosis velocity at 23°C. slows as the pressure is increased in steps of 1000 lbs. per square inch. In some cells a regular slowing is observed, in others there is little slowing until 4000 to 6000 lbs. per square inch, when a rapid slowing appears, with only 50 per cent to 30 per cent of the original velocity at 9000 lbs. per square inch. The cyclosis does not completely stop at 10000 lbs. per square inch. The pressure effect is reversible unless the cells have been kept too long at the high pressure. At low temperatures (10°C.) and at temperatures near and above (32°–38°C.) the optimum temperature for maximum cyclosis (35–36°C.) pressures of 3000 to 6000 lbs. per square inch cause only further slowing of cyclosis, with no reversal of the temperature effect, such as has been observed in pressure-temperature studies on the luminescence of luminous bacteria. Sudden increase in temperature may cause shock stoppage of cyclosis as well as sudden decrease in temperature. PMID:19873318

Experimental Spectroscopic Studies of Carbon Monoxide (CO) Fluorescence at High Temperatures and Pressures.

PubMed

Carrivain, Olivier; Orain, Mikael; Dorval, Nelly; Morin, Celine; Legros, Guillaume

2017-10-01

Two-photon excitation laser-induced fluorescence of carbon monoxide (CO-LIF) is investigated experimentally in order to determine the applicability of this technique for imaging CO concentration in aeronautical combustors. Experiments are carried out in a high temperature, high-pressure test cell, and in a laminar premixed CH 4 /air flame. Influence of temperature and pressure on CO-LIF spectra intensity and shape is reported. The experimental results show that as pressure increases, the CO-LIF excitation spectrum becomes asymmetric. Additionally, the spectrum strongly shifts to the red with a quadratic dependence of the collisional shift upon pressure, which is different from the classical behavior where the collisional shift is proportional to pressure. Moreover, pressure line broadening cannot be reproduced by a Lorenztian profile in the temperature range investigated here (300-1750 K) and, therefore, an alternative line shape is suggested.

Crowdsourcing urban air temperatures from smartphone battery temperatures

NASA Astrophysics Data System (ADS)

Overeem, A.; Robinson, J. C. R.; Leijnse, H.; Steeneveld, G. J.; Horn, B. K. P.; Uijlenhoet, R.

2013-08-01

Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. A straightforward heat transfer model is employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas.

Influence of air temperature on electric consumption in Moscow

NASA Astrophysics Data System (ADS)

Lokoshchenko, Mikhail A.; Nikolayeva, Nataliya A.

2017-04-01

' contribution). A relation of energy consumption with the relative humidity is absent whereas a relation of energy consumption with the water vapor pressure e indirectly reflects a dependence of this parameter on the air temperature. Use of multiple and partial correlation between E, T and e confirmed an absence of direct relation between energy consumption and water vapor pressure. Authors are much grateful to System Operator of Unified Energy System of Russia for given data about electric power consumption in Moscow region.

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

Noncontact Monitoring of Respiration by Dynamic Air-Pressure Sensor.

PubMed

Takarada, Tohru; Asada, Tetsunosuke; Sumi, Yoshihisa; Higuchi, Yoshinori

2015-01-01

We have previously reported that a dynamic air-pressure sensor system allows respiratory status to be visually monitored for patients in minimally clothed condition. The dynamic air-pressure sensor measures vital information using changes in air pressure. To utilize this device in the field, we must clarify the influence of clothing conditions on measurement. The present study evaluated use of the dynamic air-pressure sensor system as a respiratory monitor that can reliably detect change in breathing patterns irrespective of clothing. Twelve healthy volunteers reclined on a dental chair positioned horizontally with the sensor pad for measuring air-pressure signals corresponding to respiration placed on the seat back of the dental chair in the central lumbar region. Respiratory measurements were taken under 2 conditions: (a) thinly clothed (subject lying directly on the sensor pad); and (b) thickly clothed (subject lying on the sensor pad covered with a pressure-reducing sheet). Air-pressure signals were recorded and time integration values for air pressure during each expiration were calculated. This information was compared with expiratory tidal volume measured simultaneously by a respirometer connected to the subject via face mask. The dynamic air-pressure sensor was able to receive the signal corresponding to respiration regardless of clothing conditions. A strong correlation was identified between expiratory tidal volume and time integration values for air pressure during each expiration for all subjects under both clothing conditions (0.840-0.988 for the thinly clothed condition and 0.867-0.992 for the thickly clothed condition). These results show that the dynamic air-pressure sensor is useful for monitoring respiratory physiology irrespective of clothing.

Dual-pump CARS of Air in a Heated Pressure Vessel up to 55 Bar and 1300 K

NASA Technical Reports Server (NTRS)

Cantu, Luca; Gallo, Emanuela; Cutler, Andrew D.; Danehy, Paul M.

2014-01-01

Dual-pump Coherent anti-Stokes Raman scattering (CARS) measurements have been performed in a heated pressure vessel at NASA Langley Research Center. Each measurement, consisting of 500 single shot spectra, was recorded at a fixed location in dry air at various pressures and temperatures, in a range of 0.03-55×10(exp 5) Pa and 300-1373 K, where the temperature was varied using an electric heater. The maximum output power of the electric heater limited the combinations of pressures and temperatures that could be obtained. Charts of CARS signal versus temperature (at constant pressure) and signal versus pressure (at constant temperature) are presented and fit with an empirical model to validate the range of capability of the dual-pump CARS technique; averaged spectra at different conditions of pressure and temperature are also shown.

Microfluidic pressure sensing using trapped air compression.

PubMed

Srivastava, Nimisha; Burns, Mark A

2007-05-01

We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid-air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d approximately 50 microm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700-100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions.

Microfluidic pressure sensing using trapped air compression

PubMed Central

Srivastava, Nimisha; Burns, Mark A.

2010-01-01

We have developed a microfluidic method for measuring the fluid pressure head experienced at any location inside a microchannel. The principal component is a microfabricated sealed chamber with a single inlet and no exit; the entrance to the single inlet is positioned at the location where pressure is to be measured. The pressure measurement is then based on monitoring the movement of a liquid–air interface as it compresses air trapped inside the microfabricated sealed chamber and calculating the pressure using the ideal gas law. The method has been used to measure the pressure of the air stream and continuous liquid flow inside microfluidic channels (d ~ 50 μm). Further, a pressure drop has also been measured using multiple microfabricated sealed chambers. For air pressure, a resolution of 700 Pa within a full-scale range of 700–100 kPa was obtained. For liquids, pressure drops as low as 70 Pa were obtained in an operating range from 70 Pa to 10 kPa. Since the method primarily uses a microfluidic sealed chamber, it does not require additional fabrication steps and may easily be incorporated in several lab-on-a-chip fluidic applications for laminar as well as turbulent flow conditions. PMID:17476384

Association between lower air pressure and the onset of ischemic colitis: a case-control study.

PubMed

Kimura, Takefumi; Shinji, Akihiro; Tanaka, Naoki; Koinuma, Masayoshi; Yamaura, Maki; Nagaya, Tadanobu; Joshita, Satoru; Komatsu, Michiharu; Umemura, Takeji; Horiuchi, Akira; Wada, Shuichi; Tanaka, Eiji

2017-09-01

Ischemic colitis (IC) often affects the elderly. Proarteriosclerotic factors, such as hypertension and smoking, and cardiovascular disease are considered major contributors to IC. Although a possible link between certain cerebrocardiovascular disorders and meteorological phenomena has been reported, the relationship between IC onset and weather changes remains uninvestigated. This study examined whether specific meteorological factors were associated with the occurrence of IC. We retrospectively enrolled 303 patients who had been diagnosed with IC between January 2003 and June 2010 at Suwa Red Cross Hospital in Nagano Prefecture, Japan. The meteorological data of the days on which IC patients visited the hospital (IC+ days) were compared with those of the days on which IC patients did not (IC- days). Univariate analysis indicated that IC+ days had significantly lower air pressure (P<0.001), depressed air pressure from the previous day (P<0.001), and fewer daylight hours (P<0.001), as well as higher air temperature (P=0.017), air humidity (P=0.004), wind velocity (P<0.001), and rainfall (P=0.012) compared with IC- days. Multivariate logistic regression analysis of the meteorological data showed that air pressure (odds ratio: 0.935, P<0.001) and change in air pressure from the previous day (odds ratio: 0.934, P<0.001) were related to onset of IC. Lower air pressure and decrease in air pressure from the previous day are possible novel factors associated with the development of IC.

The relationships between air exposure, negative pressure, and hemolysis.

PubMed

Pohlmann, Joshua R; Toomasian, John M; Hampton, Claire E; Cook, Keith E; Annich, Gail M; Bartlett, Robert H

2009-01-01

The purpose of this study was to describe the hemolytic effects of both negative pressure and an air-blood interface independently and in combination in an in vitro static blood model. Samples of fresh ovine or human blood (5 ml) were subjected to a bubbling air interface (0-100 ml/min) or negative pressure (0-600 mm Hg) separately, or in combination, for controlled periods of time and analyzed for hemolysis. Neither negative pressure nor an air interface alone increased hemolysis. However, when air and negative pressure were combined, hemolysis increased as a function of negative pressure, the air interface, and time. Moreover, when blood samples were exposed to air before initiating the test, hemolysis was four to five times greater than samples not preexposed to air. When these experiments were repeated using freshly drawn human blood, the same phenomena were observed, but the hemolysis was significantly higher than that observed in sheep blood. In this model, hemolysis is caused by combined air and negative pressure and is unrelated to either factor alone.

The Relationships between Air Exposure, Negative Pressure and Hemolysis

PubMed Central

Pohlmann, Joshua R.; Toomasian, John M.; Hampton, Claire E.; Cook, Keith E.; Annich, Gail M.; Bartlett, Robert H.

2013-01-01

The purpose of this study was to describe the hemolytic effects of both negative pressure and an air-blood interface independently and in combination in an in-vitro static blood model. Samples of fresh ovine or human blood (5 mL) were subjected to a bubbling air interface (0–100 mL/min) or negative pressure (0–600 mmHg) separately, or in combination, for controlled periods of time, and analyzed for hemolysis. Neither negative pressure nor an air interface alone increased hemolysis. However, when air and negative pressure were combined, hemolysis increased as a function of negative pressure, the air interface, and time. Moreover, when blood samples were exposed to air prior to initiating the test, hemolysis was 4–5 times greater than samples not pre-exposed to air. When these experiments were repeated using freshly drawn human blood the same phenomena were observed, but the hemolysis was significantly higher than that observed in sheep blood. In this model, hemolysis is caused by combined air and negative pressure and is unrelated to either factor alone. PMID:19730004

The effect of compressed air massage on skin blood flow and temperature.

PubMed

Mars, Maurice; Maharaj, Sunil S; Tufts, Mark

2005-01-01

Compressed air massage is a new treatment modality that uses air under pressure to massage skin and muscle. It is claimed to improve skin blood flow but this has not been verified. Several pilot studies were undertaken to determine the effects of compressed air massage on skin blood flow and temperature. Skin blood flow (SBF), measured using laser Doppler fluxmetry and skin temperature was recorded under several different situations: (i) treatment, at 1 Bar pressure using a single-hole (5-mm) applicator head, for 1 min at each of several sites on the right and left lower legs, with SBF measured on the dorsum of the left foot; (ii) at the same treatment pressure, SBF was measured over the left tibialis anterior when treatment was performed at different distances from the probe; (iii) SBF and skin temperature of the lower leg were measured with treatment at 0 or 1 Bar for 45 min, using two different applicator heads; (iv) SBF was measured on the dorsum of the foot of 10 subjects with treatment for 1 min at 0, 0.5, 1, 1.5 and 2 Bar using three different applicator heads. (i) SBF of the left foot was not altered by treatment of the right leg or chest, but was significantly increased during treatment of the left sole and first web, p < 0.0001. (ii) SBF over the tibialis anterior was increased when treatment was 5 cm from the probe, p < 0.0001, but not when 10 cm away. iii) SBF was significantly elevated throughout the 45-min treatments at 1 Bar and returned to normal within 1 min of stopping treatment. Skin temperature fell by 6.8 degrees C and 4.3 degrees C after 45-min treatments at 1 Bar, and slight rewarming occurred within 15 min. At 0 Bar, no change in SBF or temperature was noted. (iv) A near-linear increase in SBF was noted with increasing treatment pressure for two of the three applicator heads. Compressed air massage causes an immediate increase in SBF, and an immediate fall in SBF when treatment is stopped. The effect appears to be locally and not centrally

Cold atmospheric pressure air plasma jet for medical applications

NASA Astrophysics Data System (ADS)

Kolb, J. F.; Mohamed, A.-A. H.; Price, R. O.; Swanson, R. J.; Bowman, A.; Chiavarini, R. L.; Stacey, M.; Schoenbach, K. H.

2008-06-01

By flowing atmospheric pressure air through a direct current powered microhollow cathode discharge, we were able to generate a 2cm long plasma jet. With increasing flow rate, the flow becomes turbulent and temperatures of the jet are reduced to values close to room temperature. Utilizing the jet, yeast grown on agar can be eradicated with a treatment of only a few seconds. Conversely, animal studies show no skin damage even with exposures ten times longer than needed for pathogen extermination. This cold plasma jet provides an effective mode of treatment for yeast infections of the skin.

High temperature pressure gauge

DOEpatents

Echtler, J. Paul; Scandrol, Roy O.

1981-01-01

A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

A Comparative Study of Sound Speed in Air at Room Temperature between a Pressure Sensor and a Sound Sensor

ERIC Educational Resources Information Center

Amrani, D.

2013-01-01

This paper deals with the comparison of sound speed measurements in air using two types of sensor that are widely employed in physics and engineering education, namely a pressure sensor and a sound sensor. A computer-based laboratory with pressure and sound sensors was used to carry out measurements of air through a 60 ml syringe. The fast Fourier…

Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

PubMed

Nelson, Jacob A; Bugbee, Bruce

2015-01-01

The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes

PubMed Central

Nelson, Jacob A.; Bugbee, Bruce

2015-01-01

The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies. PMID:26448613

Ignition of lean fuel-air mixtures in a premixing-prevaporizing duct at temperatures up to 1000 K

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1980-01-01

Conditions were determined in a premixing prevaporizing fuel preparation duct at which ignition occurred. An air blast type fuel injector with nineteen fuel injection points was used to provide a uniform spatial fuel air mixture. The range of inlet conditions where ignition occurred were: inlet air temperatures of 600 to 1000 K air pressures of 180 to 660 kPa, equivalence ratios (fuel air ratio divided by stoichiometric fuel air ratio) from 0.12 to 1.05, and velocities from 3.5 to 30 m/s. The duct was insulated and the diameter was 12 cm. Mixing lengths were varied from 16.5 to 47.6 and residence times ranged from 4.6 to 107 ms. The fuel was no. 2 diesel. Results show a strong effect of equivalence ratio, pressure and temperature on the conditions where ignition occurred. The data did not fit the most commonly used model of auto-ignition. A correlation of the conditions where ignition would occur which apply to this test apparatus over the conditions tested is (p/V) phi to the 1.3 power = 0.62 e to the 2804/T power where p is the pressure in kPa, V is the velocity in m/e, phi is the equivalence ratio, and T is the temperature in K. The data scatter was considerable, varying by a maximum value of 5 at a given temperature and equivalence ratio. There was wide spread in the autoignition data contained in the references.

High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

2004-01-01

The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

Generation of low-temperature air plasma for food processing

NASA Astrophysics Data System (ADS)

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

2015-11-01

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

[Aerodynamics study on pressure changes inside pressure-type whole-body plethysmograph produced by flowing air].

PubMed

Xu, Wei-Hua; Shen, Hua-Hao

2010-02-25

When using pressure-type plethysmography to test lung function of rodents, calculation of lung volume is always based on Boyle's law. The precondition of Boyle's law is that perfect air is static. However, air in the chamber is flowing continuously when a rodent breathes inside the chamber. Therefore, Boyle's law, a principle of air statics, may not be appropriate for measuring pressure changes of flowing air. In this study, we deduced equations for pressure changes inside pressure-type plethysmograph and then designed three experiments to testify the theoretic deduction. The results of theoretic deduction indicated that increased pressure was generated from two sources: one was based on Boyle's law, and the other was based on the law of conservation of momentum. In the first experiment, after injecting 0.1 mL, 0.2 mL, 0.4 mL of air into the plethysmograph, the pressure inside the chamber increased sharply to a peak value, then promptly decreased to horizontal pressure. Peak values were significantly higher than the horizontal values (P<0.001). This observation revealed that flowing air made an extra effect on air pressure in the plethysmograph. In the second experiment, the same volume of air was injected into the plethysmograph at different frequencies (0, 0.5, 1, 2, 3 Hz) and pressure changes inside were measured. The results showed that, with increasing frequencies, the pressure changes in the chamber became significantly higher (P<0.001). In the third experiment, small animal ventilator and pipette were used to make two types of airflow with different functions of time. The pressure changes produced by the ventilator were significantly greater than those produced by the pipette (P<0.001). Based on the data obtained, we draw the conclusion that, the flow of air plays a role in pressure changes inside the plethysmograph, and the faster the airflow is, the higher the pressure changes reach. Furthermore, the type of airflow also influences the pressure changes.

Simultaneous Luminescence Pressure and Temperature Mapping

NASA Technical Reports Server (NTRS)

Buck, Gregory M. (Inventor)

1998-01-01

A simultaneous luminescence pressure and temperature mapping system is developed including improved dye application techniques for surface temperature and pressure measurements from 5 torr to 1000 torr with possible upgrade to from 0.5 torr to several atmospheres with improved camera resolution. Adsorbed perylene dye on slip-cast silica is pressure (oxygen) sensitive and reusable to relatively high temperatures (-150 C). Adsorbed luminescence has an approximately linear color shift with temperature, which can be used for independent temperature mapping and brightness pressure calibration with temperature.

Characterization of air temperature in modern ion chambers due to phantom geometry and ambient temperature changes.

PubMed

Saenz, Daniel L; Kirby, Neil; Gutiérrez, Alonso N

2016-07-01

Temperature and pressure corrections are necessary to account for the varying mass of air in the sensitive volume of a vented ionization chamber (IC) when performing absolute dose measurements. Locations commonly used to measure the presumed IC air temperature may not accurately represent the chamber cavity air temperature, and phantoms undergoing temperature changes further compound the problem. Prior studies have characterized thermal equilibrium in separate phantoms for Farmer chambers alone. However, the purpose of this study was to characterize the cavity air temperature dependence on changes in the ambient temperature and phantom geometry configuration for a wider and more modern variety of chambers to determine if previously published wait times apply to these chambers as well. Thermal conduction properties were experimentally investigated by modifying a PTW 0.3 cm(3) Semiflex IC with a thermocouple replacing the central electrode. Air cavity temperature versus time was recorded in three phantom geometries characteristic of common absolute dose measurements. The phantoms were (15 ± 1) °C before measurement with an IC at the treatment vault temperature of (21 ± 1) °C. Simulations were conducted to provide a theoretical basis for the measurements and to simulate temperature response of a PTW PinPoint® and Farmer chamber. The simulation methods were first validated by comparison with measured Semiflex chamber thermal response curves before extension to the other chambers. Two thermal equilibria curves were recorded on different time scales. IC temperature initially dropped to the colder phantom temperature but subsequently increased as the phantom itself equilibrated with the warmer room temperature. In a large phantom of dimensions (25.5 × 25.5 × 23.4) cm(3), 3 min was required before the IC temperature reached within 0.5 °C of its equilibrium within the phantom. Similarly, wait times of 2 min were needed for 7.5 and 2 cm slab phantoms. Recording

Measuring Ancient Air Pressure Using Fossilized Cyanobacteria

NASA Astrophysics Data System (ADS)

Silverman, S. N.; Som, S. M.; Gordon, R.; Bebout, B.

2016-12-01

The evolution of Earth's atmosphere has been governed by biological evolution. The dominant air component, nitrogen, has undergone substantial variation over geological time. Today, the partial pressure of nitrogen is 0.79 bar, but this value could have been much higher during early Earth1. The nitrogen partial pressure is postulated to have dropped to a maximum of 0.5 bar before the Great Oxidation Event 2.4 billion years ago, and subsequently recovered to the 0.8 bar value of our modern atmosphere over the next 330 million years2. We are placing constraints on the trajectory of this recovery by investigating how nitrogen partial pressure influences the morphology of a certain species of filamentous cyanobacteria that has been found fossilized in 2 billion year old rocks. These filamentous cyanobacteria convert nitrogen from its dissolved gaseous state (N2) to a biologically useful state (i.e. NH3) when the latter is present at growth-limiting concentrations in their aquatic environment. Such cyanobacteria develop heterocysts (specialized, visually distinct cells), which fix the nitrogen and laterally distribute it to neighboring cells along the one-dimensional filament. We suggest that the distance between heterocysts reflects the nitrogen partial pressure dissolved in water, which is related to atmospheric pN2 by Henry's law. In the laboratory, we are quantifying the relationship between heterocyst distance, variance and covariance to atmospheric pN2 by subjecting cyanobacteria (in media devoid of nitrate) to different partial pressures of N2 at a constant temperature and lighting for the representative species Anabaena variabilis. As far as we know, such experiments have not been previously conducted. This new geobarometer will complement existing methods of quantifying ancient nitrogen partial pressure. 1Goldblatt, Colin, et al. "Nitrogen-enhanced greenhouse warming on early Earth." Nature Geoscience 2 (2009): 891-896. 2Som, S., et al. "Earth's air pressure 2

Validation of a dew-point generator for pressures up to 6 MPa using nitrogen and air

NASA Astrophysics Data System (ADS)

Bosma, R.; Mutter, D.; Peruzzi, A.

2012-08-01

A new primary humidity standard was developed at VSL that, in addition to ordinary operation with air and nitrogen at atmospheric pressure, can be operated with other carrier gases such as natural gas at pressures up to 6 MPa and SF6 at pressures up to 1 MPa. The temperature range of the standard is from -80 °C to +20 °C. In this paper, we report the validation of the new primary dew-point generator in the temperature range -41 °C to +5 °C and the pressure range 0.1 MPa to 6 MPa using nitrogen and air. For the validation the flow through the dew-point generator was varied up to 10 l min-1 (at 23 °C and 1013 hPa) and the dew point of the gas entering the generator was varied up to 15 °C above the dew point exiting the generator. The validation results showed that the new generator, over the tested temperature and pressure range, can be used with a standard uncertainty of 0.02 °C frost/dew point. The measurements used for the validation at -41 °C and -20 °C with nitrogen and at +5 °C with air were also used to calculate the enhancement factor at pressures up to 6 MPa. For +5 °C the differences between the measured and literature values were compatible with the respective uncertainties. For -41 °C and -20 °C they were compatible only up to 3 MPa. At 6 MPa a discrepancy was observed.

Air temperature recordings in infant incubators.

PubMed Central

Aynsley-Green, A; Roberton, N R; Rolfe, P

1975-01-01

Air temperatures were continuously recorded inside four incubators with proportional heating control and six incubators with on/off heating cycles, during routine use. The air temperatures in the former were constant throughout, with a gradient between the roof and above-mattress air temperature not exceeding 1 degree C. In contrast, the recordings from the latter models showed a regular cyclical oscillation, the duration of the cycle varying from 14 to 44 minutes. Each incubator had a characteristic profile. The roof air temperature could vary by as much as 7-1 degrees C and the above-mattress air temperature by as much as 2-6 degrees C during the cycle. The oscillation persisted in the air temperatures recorded inside an open-ended hemicylindrical heat shield when used inside these incubators, but was markedly reduced inside a closed-ended heat shield, Carbon dioxide concentration did not increase significantly inside the latter. Images FIG. 1 FIG. 2 PMID:1147654

Air Bag Applies Uniform Bonding Pressure

NASA Technical Reports Server (NTRS)

Gillespie, C. A.

1982-01-01

Air-bag box applies constant uniform pressure to tiles and other objects undergoing adhesive bonding. Box is basically a compliant clamp with adjustable force and position. Can be used on irregular surfaces as well as on flat ones. Pressurized air is fed to bag through a tube so that it expands, filling the box and pressing against work. Bag adopts a contour that accommodates surface under open side of box.

"Deflategate": Time, Temperature, and Moisture Effects on Football Pressure

NASA Astrophysics Data System (ADS)

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

2016-09-01

In a recent paper in TPT, DiLisi and Rarick used the National Football League "Deflategate" controversy to introduce to physics students the physics of a bouncing ball. In this paper, we measure and analyze the environmental effects of time, ambient temperature, and moisture on the internal pressure of an NFL football. We focus on the rate of pressure recovery that occurs when a cold football (either wet or dry) is returned to the warm locker room environment where the pressure was initially measured. Both studies stem from the so-called NFL "Deflategate" controversy in which footballs that initially met a minimum internal pressure requirement were rechecked at halftime of the AFC Championship game, and in some cases were reported to have fallen below the minimum pressure requirement. The question is whether the pressure changes were due to environmental exposure or rather to some air being released from the balls, or both.

The effect of temperature on pulsed positive streamer discharges in air over the range 292 K–1438 K

NASA Astrophysics Data System (ADS)

Ono, Ryo; Ishikawa, Yuta

2018-05-01

The effect of temperature on pulsed positive streamer discharges in air is measured by comparing atmospheric-pressure, high-temperature discharges with low-pressure, room-temperature discharges at the same air densities n and discharge voltages. Both discharges have the same reduced electric field E/n, so the differences between the two discharges only depend on the temperature, which is varied from 292 K to 1438 K. Temperature affects the discharge pulse energy most significantly; at 1438 K, the energy of an atmospheric-pressure discharge pulse is approximately 30 times larger than that of the corresponding 20.5 kPa, room-temperature discharge. Temperature also affects the shapes of the streamers when K, but no significant effect is observed for K. There is also no significant temperature effect on the spatially integrated intensity of N2(C–B) emission. However, temperature strongly affects the ratio of the integrated emission intensity to the discharge energy. No effect of the temperature is observed on the propagation velocity of the primary streamer or on the length of the secondary streamer.

Influence of ambient air pressure on effervescent atomization

NASA Technical Reports Server (NTRS)

Chen, S. K.; Lefebvre, A. H.; Rollbuhler, J.

1993-01-01

The influence of ambient air pressure on the drop-size distributions produced in effervescent atomization is examined in this article. Also investigated are the effects on spray characteristics of variations in air/liquid mass ratio, liquid-injection pressure, and atomizer discharge-orifice diameter at different levels of ambient air pressure. It is found that continuous increase in air pressure above the normal atmospheric value causes the mean drop-size to first increase up to a maximum value and then decline. An explanation for this characteristic is provided in terms of the various contributing factors to the overall atomization process. It is also observed that changes in atomizer geometry and operating conditions have little effect on the distribution of drop-sizes in the spray.

Multispectrum Analysis of 12CH4 in the v4 Band: I. Air-Broadened Half Widths, Pressure-Induced Shifts, Temperature Dependences and Line Mixing

NASA Technical Reports Server (NTRS)

Smith, MaryAnn H.; Benner, D. Chris; Predoi-Cross, Adriana; Venkataraman, Malathy Devi

2009-01-01

Lorentz air-broadened half widths, pressure-induced shifts and their temperature dependences have been measured for over 430 transitions (allowed and forbidden) in the v4 band of (CH4)-12 over the temperature range 210 to 314 K. A multispectrum non linear least squares fitting technique was used to simultaneously fit a large number of high-resolution (0.006 to 0.01/cm) absorption spectra of pure methane and mixtures of methane diluted with dry air. Line mixing was detected for pairs of A-, E-, and F-species transitions in the P- and R-branch manifolds and quantified using the off-diagonal relaxation matrix elements formalism. The measured parameters are compared to air- and N2-broadened values reported in the literature for the v4 and other bands. The dependence of the various spectral line parameters upon the tetrahedral symmetry species and rotational quantum numbers of the transitions is discussed. All data used in the present work were recorded using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak.

Simultaneous velocity and pressure quantification using pressure-sensitive flow tracers in air

NASA Astrophysics Data System (ADS)

Zhang, Peng; Peterson, Sean; Porfiri, Maurizio

2017-11-01

Particle-based measurement techniques for assessing the velocity field of a fluid have advanced rapidly over the past two decades. Full-field pressure measurement techniques have remained elusive, however. In this work, we aim to demonstrate the possibility of direct simultaneous planar velocity and pressure measurement of a high speed aerodynamic flow by employing novel pressure-sensitive tracer particles for particle image velocimetry (PIV). Specifically, the velocity and pressure variations of an airflow through a converging-diverging channel are studied. Polystyrene microparticles embedded with a pressure-sensitive phosphorescent dye-platinum octaethylporphyrin (PtOEP)-are used as seeding particles. Due to the oxygen quenching effect, the emission lifetime of PtOEP is highly sensitive to the oxygen concentration, that is, the partial pressure of oxygen, in the air. Since the partial pressure of oxygen is linearly proportional to the air pressure, we can determine the air pressure through the phosphorescence emission lifetime of the dye. The velocity field is instead obtained using traditional PIV methods. The particles have a pressure resolution on the order of 1 kPa, which may be improved by optimizing the particle size and dye concentration to suit specific flow scenarios. This work was supported by the National Science Foundation under Grant Number CBET-1332204.

Experimental research on the indoor temperature and humidity fields in radiant ceiling air-conditioning system under natural ventilation

NASA Astrophysics Data System (ADS)

Huang, Tao; Xiang, Yutong; Wang, Yonghong

2017-05-01

In this paper, the indoor temperature and humidity fields of the air in a metal ceiling radiant panel air conditioning system with fresh air under natural ventilation were researched. The temperature and humidity distributions at different height and different position were compared. Through the computation analysis of partial pressure of water vapor, the self-recovery characteristics of humidity after the natural ventilation was discussed.

Drop impact on a solid surface at reduced air pressure

NASA Astrophysics Data System (ADS)

Langley, Kenneth; Li, E. Q.; Tian, Y. S.; Hicks, P. D.; Thoroddsen, S. T.

2017-11-01

When a drop approaches a solid surface at atmospheric pressure, the lubrication pressure within the air forms a dimple in the bottom of the drop resulting in the entrainment of an air disc upon impact. Reducing the ambient air pressure below atmospheric has been shown to suppress splashing and the compression of the intervening air could be significant on the air disc formation; however, to date there have been no experimental studies showing how the entrainment of the air disc is affected by reducing the ambient pressure. Using ultra-high-speed interferometry, at up to 5 Mfps, we investigate droplet impacts onto dry solid surfaces in reduced ambient air pressures with particular interest in what happens as rarified gas effects become important, i.e. when the thickness of the air layer is of the same magnitude as the mean free path of the air molecules. Experimental data will be presented showing novel phenomena and comparisons will be drawn with theoretical models from the literature.

Planar Imaging of Hydroxyl in a High Temperature, High Pressure Combustion Facility

NASA Technical Reports Server (NTRS)

Hicks, Yolanda R.; Locke, Randy J.; Anderson, Robert C.; Ockunzzi, Kelly A.

1995-01-01

An optically accessible flame tube combustor is described which has high temperature, pressure, and air flow capabilities. The windows in the combustor measure 3.8 cm axially by 5.1 cm radially, providing 67 percent optical access to the square cross section flow chamber. The instrumentation allows one to examine combusting flows and combustor subcomponents, such as fuel injectors and air swirlers. These internal combustor subcomponents have previously been studied only with physical probes, such as temperature and species rakes. Planar laser-induced fluorescence (PLIF) images of OH have been obtained from this lean burning combustor burning Jet-A fuel. These images were obtained using various laser excitation lines of the OH A yields X (1,0) band for two fuel injector configurations with pressures ranging from 1013 kPa (10 atm) to 1419 kPa (14 atm), and equivalence ratios from 0.41 to 0. 59. Non-uniformities in the combusting flow, attributed to differences in fuel injector configuration, are revealed by these images.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-11-15

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

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-12-13

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

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N; Geohegan, David Bruce

2013-10-29

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

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-10-25

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

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2017-09-12

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

Data Assimilation Experiments Using Quality Controlled AIRS Version 5 Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel

2009-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains a number of significant improvements over Version 4. Two very significant improvements are described briefly below. 1) The AIRS Science Team Radiative Transfer Algorithm (RTA) has now been upgraded to accurately account for effects of non-local thermodynamic equilibrium on the AIRS observations. This allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval algorithm during both day and night. Following theoretical considerations, tropospheric temperature profile information is obtained almost exclusively from clear column radiances in the 4.3 micron CO2 band in the AIRS Version 5 temperature profile retrieval step. These clear column radiances are a derived product that are indicative of radiances AIRS channels would have seen if the field of view were completely clear. Clear column radiances for all channels are determined using tropospheric sounding 15 micron CO2 observations. This approach allows for the generation of accurate values of clear column radiances and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel clear column radiances. These error estimates are used for quality control of the retrieved products. Based on error estimate thresholds, each temperature profiles is assigned a characteristic pressure, pg, down to which the profile is characterized as good for use for data assimilation purposes. We have conducted forecast impact experiments assimilating AIRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the

Pressure ulcer incidence and progression in critically ill subjects: influence of low air loss mattress versus a powered air pressure redistribution mattress.

PubMed

Black, Joyce; Berke, Christine; Urzendowski, Gail

2012-01-01

The primary objective of this study was to compare facility-acquired pressure ulcer incidence and progression of pressure ulcers present on admission in critically ill patients, using 2 different support surfaces. We completed a comparison cohort study in a surgical intensive care unit (ICU). The study setting was a 12-bed cardiovascular ICU in a university-based hospital in the Midwestern United States. The sample comprised 52 critically ill patients; 31 were placed on low air loss weight-based pressure redistribution-microclimate management system beds and 21 were placed on integrated powered air pressure redistribution beds. Prior to the start of the study, 5 low airloss beds were placed in open rooms in the cardiovascular surgical ICU. Inclusion criteria were anticipated ICU stay of 3 days, and patients did not receive a speciality bed for pulmonary or wound issues. Initial assessment of the patients included risk assessment and prior events that would increase risk for pressure ulcer development such as extended time in operating room, along with skin assessment for existing pressure ulcers. Subjects in both groups had ongoing skin assessment every 3 to 4 days and a subjective evaluation of heel elevation and turning or repositioning by the researcher. Data were collected until the subjects were dismissed from the ICU. Patients admitted to the unit were assigned to open rooms following the usual protocols. The mean length of stay was 7.0 days, with an 8.1-day length of stay for subjects on "low air loss with microclimate management" beds (LAL-MCM) and 6.6 days on the integrated power pressure air redistribution (IP-AR) beds (P = NS). The incidence of pressure ulcers on the buttocks, sacrum, or coccyx was 0% (0/31) on the low air loss bed and 18% (4/21) on the IP-AR bed (P = .046). Five subjects had 6 pressure ulcers on admission. Two pressure ulcers on 2 patients worsened on the integrated power air redistribution beds, which required specialty bed rental

Laser-based measurements of OH in high pressure CH4/air flames

NASA Technical Reports Server (NTRS)

Battles, B. E.; Hanson, R. K.

1991-01-01

Narrow-linewidth laser absorption measurements are reported from which mole fraction and temperature of OH are determined in high-pressure (1-10 atm), lean CH4/air flames. These measurements were made in a new high pressure combustion facility which incorporates a traversable flat flame burner, providing spatially and temporally uniform combustion gases at pressures up to 10 am. A commercially avialable CW ring dye laser was used with an intracavity doubling crystal to provide near-UV single mode output at approximately 306 nm. The UV beam was rapidly scanned over 120 GHz (0.1 sec scan duration) to resolve the absorption lineshape of the A-X (0,0) R1(7)/R1(11) doublet of the OH radical. From the doublet's absorption lineshape, the temperature was determined; and from peak absorption, Beer's Law was employed to find the mole fraction of OH. These data were obtained as a function of height above the flame at various pressures.

Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

NASA Astrophysics Data System (ADS)

Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

2013-04-01

Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

A Balanced-pressure Sliding Seal for Transfer of Pressurized Air Between Stationary and Rotating Parts

NASA Technical Reports Server (NTRS)

Curren, Arthur N; Cochran, Reeves P

1957-01-01

A combination sliding-ring and pressure-balancing seal capable of transferring pressurize air from stationary to rotating parts was developed and experimentally investigated at sliding velocities and cooling-air pressures up to 10,000 feet per minute and 38.3 pounds per square inch absolute, respectively. Leakage of cooling air was completely eliminated with an expenditure of balance air less than one-fourth the leakage loss of air from labyrinth seals under the same conditions. Additional cooling of the carbon-base seal rings was required, and the maximum wear rate on the rings was about 0.0005 inch per hour.

Experimental investigation of air pressure affecting filtration performance of fibrous filter sheet.

PubMed

Xu, Bin; Yu, Xiao; Wu, Ya; Lin, Zhongping

2017-03-01

Understanding the effect of air pressure on their filtration performance is important for assessing the effectiveness of fibrous filters under different practical circumstances. The effectiveness of three classes of air filter sheets were investigated in laboratory-based measurements at a wide range of air pressures (60-130 KPa). The filtration efficiency was found most sensitive to the air pressure change at smaller particle sizes. As the air pressure increased from 60 to 130 KPa, significant decrease in filtration efficiency (up to 15%) and increase in pressure drop (up to 90 Pa) were observed. The filtration efficiency of the filter sheet with largest fiber diameter and smallest solid volume fraction was affected most, while the pressure drop of the filter sheet with smallest fiber diameter and largest solid volume fraction was affected most. The effect of air pressure on the filtration efficiency was slightly larger at greater filter face air velocity. However, the effect of air pressure on the pressure drop was negligible. The filtration efficiency and pressure drop were explicitly expressed as functions of the air pressure. Two coefficients were empirically derived and successfully accounted for the effects of air pressure on filtration efficiency and pressure drop.

MEMS Fabry-Perot sensor interrogated by optical system-on-a-chip for simultaneous pressure and temperature sensing.

PubMed

Pang, Cheng; Bae, Hyungdae; Gupta, Ashwani; Bryden, Kenneth; Yu, Miao

2013-09-23

We present a micro-electro-mechanical systems (MEMS) based Fabry-Perot (FP) sensor along with an optical system-on-a-chip (SOC) interrogator for simultaneous pressure and temperature sensing. The sensor employs a simple structure with an air-backed silicon membrane cross-axially bonded to a 45° polished optical fiber. This structure renders two cascaded FP cavities, enabling simultaneous pressure and temperature sensing in close proximity along the optical axis. The optical SOC consists of a broadband source, a MEMS FP tunable filter, a photodetector, and the supporting circuitry, serving as a miniature spectrometer for retrieving the two FP cavity lengths. Within the measured pressure and temperature ranges, experimental results demonstrate that the sensor exhibits a good linear response to external pressure and temperature changes.

Spectral Line Parameters Including Temperature Dependences of Self- and Air-Broadening in the 2 (left arrow) 0 Band of CO at 2.3 micrometers

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Mantz, A. W.; Sung, K.; Brown, L. R.; Predoi-Cross, A.

2012-01-01

Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2<--0 band of C-12 O-16 from analyzing high-resolution and high signal-to-noise spectra recorded with two different Fourier transform spectrometers. A total of 28 spectra, 16 self-broadened and 12 air-broadened, recorded using high- purity (greater than or equal to 99.5% C-12-enriched) CO samples and CO diluted with dry air(research grade) at different temperatures and pressures, were analyzed simultaneously to maximize the accuracy of the retrieved parameters. The sample temperatures ranged from 150 to 298K and the total pressures varied between 5 and 700 Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters (including Herman-Wallis coefficients), rather than determining individual line positions and intensities. Self-and air-broadened Lorentz half-width coefficients, their temperature dependence exponents, self- and air-pressure-induced shift coefficients, their temperature dependences, self- and air-line mixing coefficients, their temperature dependences and speed dependence have been retrieved from the analysis. Speed-dependent line shapes with line mixing employing off-diagonal relaxation matrix element formalism were needed to minimize the fit residuals. This study presents a precise and complete set of spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions.

Emission spectroscopy of an atmospheric pressure plasma jet operated with air at low frequency

NASA Astrophysics Data System (ADS)

Giuliani, L.; Gallego, J. L.; Minotti, F.; Kelly, H.; Grondona, D.

2015-03-01

Low-temperature, high-pressure plasma jets have an extensive use in plasma biology and plasma medicine, such as pathogen deactivation, wound disinfection, stopping of bleeding without damage of healthy tissue, acceleration of wound healing, control of bio-film proliferation, etc. In this work, a spectroscopic characterization of a typical plasma jet, operated in air at atmospheric pressure, is reported. Within the spectrum of wavelengths from 200 to 450 nm all remarkable emissions of N2 were monitored. Spectra of the N2 2nd positive system (C3Πu-B3Πg) emitted in air are the most convenient for plasma diagnostics, since they enable to determine electronic Te, rotational Tr and vibrational Tv temperatures by fitting the experimental spectra with the simulated ones. We used SPECAIR software for spectral simulation and obtained the best fit with all these temperatures about 3500K. The conclusion that all temperatures are equal, and its relatively high value, is consistent with the results of a previous work, where it was found that the experimentally determined electrical characteristic was consistent with the model of a thermal arc discharge, together with a highly collisional cathode sheet.

Effects of Barometric Pressure and Temperature on Acute Ischemic Stroke Hospitalization in Augusta, GA.

PubMed

Guan, Weihua; Clay, Sandra J; Sloan, Gloria J; Pretlow, Lester G

2018-06-24

Several studies worldwide have demonstrated significant relationships between meteorological parameters and stroke events. However, authors often reported discordant effects of both barometric pressure and air temperature on stroke occurrence. The present study investigated whether there was an association between weather parameters (barometric pressure and temperature) and ischemic stroke hospitalization. The aim of the study was to find out whether daily barometric pressure may be used as a prognostic variable to evaluate the workload change of a neurological intensive care unit. We conducted a retrospective review study in which we collected the independent (barometric pressure and temperature) and dependent variables (stroke hospitalization) every 24 h for the periods 10/1/2016-4/30/2017 at Augusta University Medical Center of Augusta, GA. We analyzed the data with zero-inflated Poisson model to assess the relationship between the barometric pressure, temperature, and daily stroke hospitalization. The results showed that there was a significantly correlation between daily barometric pressure variation and daily stroke hospitalization, especially on elder male patients (≥ 65). Stroke events were more likely to occur in the patients with risk factors than in those without risk factors when exposed to barometric pressure and temperature changes. Decreased barometric pressure and increased temperature were associated with increased daily stroke hospitalization. Furthermore, there was a potential delayed effect of increased stroke events after cold temperature exposure. Barometric pressure and temperature changes over the preceding 24 h are associated with daily stroke hospitalization. These findings may enhance our understanding of relationship between stroke and weather and maybe used in the development of public health strategies to minimize the weather-related stroke risk.

Pressurized liquid extraction of diesel and air particulate standard reference materials: effect of extraction temperature and pressure.

PubMed

Schantz, Michele M; McGaw, Elizabeth; Wise, Stephen A

2012-10-02

Four particulate matter Standard Reference Materials (SRMs) available from the National Institute of Standards and Technology (NIST) were used to evaluate the effect of solvent, number of static cycles and static times, pressure, and temperature when using pressurized liquid extraction (PLE) for the extraction of polycyclic aromatic hydrocarbons (PAHs) and nitrated-PAHs. The four materials used in the study were SRM 1648a Urban Particulate Matter, SRM 1649b Urban Dust, SRM 1650b Diesel Particulate Matter, and SRM 2975 Diesel Particulate Matter (Industrial Forklift). The results from the study indicate that the choice of solvent, dichloromethane compared to toluene and toluene/methanol mixtures, had little effect on the extraction efficiency. With three to five extraction cycles, increasing the extraction time for each cycle from 5 to 30 min had no significant effect on the extraction efficiency. The differences in extraction efficiency were not significant (with over 95% of the differences being <10%) when the pressure was increased from 13.8 to 20.7 MPa. The largest increase in extraction efficiency occurred for selected PAHs when the temperature of extraction was increased from 100 to 200 °C. At 200 °C naphthalene, biphenyl, fluorene, dibenzothiophene, and anthracene show substantially higher mass fractions (>30%) than when extracted at 100 °C in all the SRMs studied. For SRM 2975, large increases (>100%) are also observed for some other PAHs including benz[a]anthracene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, benzo[ghi]perylene, and benzo[b]chrysene when extracted at the higher temperatures; however, similar trends were not observed for the other diesel particulate sample, SRM 1650b. The results are discussed in relation to the use of the SRMs for evaluating analytical methods.

Assimilation of Quality Controlled AIRS Temperature Profiles using the NCEP GFS

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste; Iredell, Lena; Rosenberg, Robert

2013-01-01

We have previously conducted a number of data assimilation experiments using AIRS Version-5 quality controlled temperature profiles as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The data assimilation and forecast system we used was the Goddard Earth Observing System Model , Version-5 (GEOS-5) Data Assimilation System (DAS), which represents a combination of the NASA GEOS-5 forecast model with the National Centers for Environmental Prediction (NCEP) operational Grid Point Statistical Interpolation (GSI) global analysis scheme. All analyses and forecasts were run at a 0.5deg x 0.625deg spatial resolution. Data assimilation experiments were conducted in four different seasons, each in a different year. Three different sets of data assimilation experiments were run during each time period: Control; AIRS T(p); and AIRS Radiance. In the "Control" analysis, all the data used operationally by NCEP was assimilated, but no AIRS data was assimilated. Radiances from the Aqua AMSU-A instrument were also assimilated operationally by NCEP and are included in the "Control". The AIRS Radiance assimilation adds AIRS observed radiance observations for a select set of channels to the data set being assimilated, as done operationally by NCEP. In the AIRS T(p) assimilation, all information used in the Control was assimilated as well as Quality Controlled AIRS Version-5 temperature profiles, i.e., AIRS T(p) information was substituted for AIRS radiance information. The AIRS Version-5 temperature profiles were presented to the GSI analysis as rawinsonde profiles, assimilated down to a case-by-case appropriate pressure level p(sub best) determined using the Quality Control procedure. Version-5 also determines case-by-case, level-by-level error estimates of the temperature profiles, which were used as the uncertainty of each temperature measurement. These experiments using GEOS-5 have shown that forecasts

Simultaneous Luminescence Pressure and Temperature Mapping System

NASA Technical Reports Server (NTRS)

Buck, Gregory M. (Inventor)

1995-01-01

A simultaneous luminescence pressure and temperature mapping system is developed including improved dye application techniques for surface temperature and pressure measurements from 5 torr to 1000 torr with possible upgrade to from 0.5 torr to several atmospheres with improved camera resolution. Adsorbed perylene dye on slip-cast silica is pressure (oxygen) sensitive and reusable to relatively high temperatures (approximately 150 C). Adsorbed luminescence has an approximately linear color shift with temperature, which can be used for independent temperature mapping and brightness pressure calibration with temperature.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

PubMed

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-07-22

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor

PubMed Central

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-01-01

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations. PMID:27455271

21 CFR 880.5550 - Alternating pressure air flotation mattress.

Code of Federal Regulations, 2013 CFR

2013-04-01

... body pressure. The device is used to prevent and treat decubitus ulcers (bed sores). (b) Classification... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices § 880.5550 Alternating pressure air flotation mattress. (a) Identification...

21 CFR 880.5550 - Alternating pressure air flotation mattress.

Code of Federal Regulations, 2010 CFR

2010-04-01

... body pressure. The device is used to prevent and treat decubitus ulcers (bed sores). (b) Classification... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices § 880.5550 Alternating pressure air flotation mattress. (a) Identification...

21 CFR 880.5550 - Alternating pressure air flotation mattress.

Code of Federal Regulations, 2014 CFR

2014-04-01

... body pressure. The device is used to prevent and treat decubitus ulcers (bed sores). (b) Classification... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices § 880.5550 Alternating pressure air flotation mattress. (a) Identification...

21 CFR 880.5550 - Alternating pressure air flotation mattress.

Code of Federal Regulations, 2011 CFR

2011-04-01

... body pressure. The device is used to prevent and treat decubitus ulcers (bed sores). (b) Classification... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices § 880.5550 Alternating pressure air flotation mattress. (a) Identification...

21 CFR 880.5550 - Alternating pressure air flotation mattress.

Code of Federal Regulations, 2012 CFR

2012-04-01

... body pressure. The device is used to prevent and treat decubitus ulcers (bed sores). (b) Classification... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices § 880.5550 Alternating pressure air flotation mattress. (a) Identification...

Measurements of KrF laser-induced O2 fluorescence in high-temperature atmospheric air

NASA Technical Reports Server (NTRS)

Grinstead, Jay H.; Laufer, Gabriel; Mcdaniel, James C., Jr.

1993-01-01

Conditions for obtaining laser-induced O2 fluorescence using a tunable KrF laser has been determined theoretically and experimentally. With this laser source, O2 rotational temperature measurement is possible even in the absence of vibrational equilibrium. Temperature measurement using a two-line excitation scheme has been demonstrated in a high-temperature atmospheric-air furnace. A measurement uncertainty of 10.7 percent for the temperature range 1325-1725 K was realized. At atmospheric pressure, O2 LIF measurements are possible for air temperatures above 1250 K. Interference from OH fluorescence in reacting flows can be avoided by the proper selection of O2 transitions. Depletion of the ground state population by the incident laser is negligible for intensities below 7.5 x 10 to the 6th W/sq cm/per cm.

Effects of air temperature and discharge on Upper Mississippi River summer water temperatures

USGS Publications Warehouse

Gray, Brian R.; Robertson, Dale M.; Rogala, James T.

2018-01-01

Recent interest in the potential effects of climate change has prompted studies of air temperature and precipitation associations with water temperatures in rivers and streams. We examined associations between summer surface water temperatures and both air temperature and discharge for 5 reaches of the Upper Mississippi River during 1994–2011. Water–air temperature associations at a given reach approximated 1:1 when estimated under an assumption of reach independence but declined to approximately 1:2 when water temperatures were permitted to covary among reaches and were also adjusted for upstream air temperatures. Estimated water temperature–discharge associations were weak. An apparently novel feature of this study is that of addressing changes in associations between water and air temperatures when both are correlated among reaches.

Conventional freezing plus high pressure-low temperature treatment: Physical properties, microbial quality and storage stability of beef meat.

PubMed

Fernández, Pedro P; Sanz, Pedro D; Molina-García, Antonio D; Otero, Laura; Guignon, Bérengère; Vaudagna, Sergio R

2007-12-01

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20°C) pressurisation (650MPa/10min) and air blast freezing (-30°C) are compared to air blast freezing plus high pressure at subzero temperature (-35°C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650MPa/20°C/10min) increased significantly expressible moisture while it decreased in pressurised (650MPa/-35°C/10min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20°C or -35°C) was very effective reducing aerobic total (2-log(10) cycles) and lactic acid bacteria counts (2.4-log(10) cycles), in fresh and salt-added samples. Frozen+pressurised beef stored at -18°C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.

Global Validation of MODIS Atmospheric Profile-Derived Near-Surface Air Temperature and Dew Point Estimates

NASA Astrophysics Data System (ADS)

Famiglietti, C.; Fisher, J.; Halverson, G. H.

2017-12-01

This study validates a method of remote sensing near-surface meteorology that vertically interpolates MODIS atmospheric profiles to surface pressure level. The extraction of air temperature and dew point observations at a two-meter reference height from 2001 to 2014 yields global moderate- to fine-resolution near-surface temperature distributions that are compared to geographically and temporally corresponding measurements from 114 ground meteorological stations distributed worldwide. This analysis is the first robust, large-scale validation of the MODIS-derived near-surface air temperature and dew point estimates, both of which serve as key inputs in models of energy, water, and carbon exchange between the land surface and the atmosphere. Results show strong linear correlations between remotely sensed and in-situ near-surface air temperature measurements (R2 = 0.89), as well as between dew point observations (R2 = 0.77). Performance is relatively uniform across climate zones. The extension of mean climate-wise percent errors to the entire remote sensing dataset allows for the determination of MODIS air temperature and dew point uncertainties on a global scale.

Correlation Between Endotracheal Tube Cuff Pressure and Tracheal Wall Pressure Using Air and Saline Filled Cuffs

DTIC Science & Technology

2017-01-31

AFRL-SA-WP-SR-2017-0004 Correlation Between Endotracheal Tube Cuff Pressure and Tracheal Wall Pressure Using Air- and Saline -Filled...Correlation Between Endotracheal Tube Cuff Pressure and Tracheal Wall Pressure Using Air- and Saline -Filled Cuffs 5a. CONTRACT NUMBER FA8650-14...descending from altitude. When using saline in the ETT cuff, TW pressure differences with the 7.5 high-volume, low-pressure cuff and 8.0 TaperGuard

A Liquid Density Standard Over Wide Ranges of Temperature and Pressure Based on Toluene

PubMed Central

McLinden, Mark O.; Splett, Jolene D.

2008-01-01

The density of liquid toluene has been measured over the temperature range −60 °C to 200 °C with pressures up to 35 MPa. A two-sinker hydrostatic-balance densimeter utilizing a magnetic suspension coupling provided an absolute determination of the density with low uncertainties. These data are the basis of NIST Standard Reference Material® 211d for liquid density over the temperature range −50 °C to 150 °C and pressure range 0.1 MPa to 30 MPa. A thorough uncertainty analysis is presented; this includes effects resulting from the experimental density determination, possible degradation of the sample due to time and exposure to high temperatures, dissolved air, uncertainties in the empirical density model, and the sample-to-sample variations in the SRM vials. Also considered is the effect of uncertainty in the temperature and pressure measurements. This SRM is intended for the calibration of industrial densimeters. PMID:27096111

Drier Air, Lower Temperatures, and Triggering of Paroxysmal Atrial Fibrillation

PubMed Central

Nguyen, Jennifer L.; Link, Mark S.; Luttmann-Gibson, Heike; Laden, Francine; Schwartz, Joel; Wessler, Benjamin S.; Mittleman, Murray A.; Gold, Diane R.; Dockery, Douglas W.

2015-01-01

Background The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes. Methods Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity). Results Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m3 decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker. Conclusions Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes. PMID:25756220

Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

PubMed

Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

2017-01-05

The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

Pressurized solid oxide fuel cell integral air accumular containment

DOEpatents

Gillett, James E.; Zafred, Paolo R.; Basel, Richard A.

2004-02-10

A fuel cell generator apparatus contains at least one fuel cell subassembly module in a module housing, where the housing is surrounded by a pressure vessel such that there is an air accumulator space, where the apparatus is associated with an air compressor of a turbine/generator/air compressor system, where pressurized air from the compressor passes into the space and occupies the space and then flows to the fuel cells in the subassembly module, where the air accumulation space provides an accumulator to control any unreacted fuel gas that might flow from the module.

Measurement of the refractive index of air in a low-pressure regime and the applicability of traditional empirical formulae

NASA Astrophysics Data System (ADS)

Schödel, René; Walkov, Alexander; Voigt, Michael; Bartl, Guido

2018-06-01

The refractive index of air is a major limiting factor in length measurements by interferometry, which are mostly performed under atmospheric conditions. Therefore, especially in the last century, measurement and description of the air refractive index was a key point in order to achieve accuracy in the realisation of the length by interferometry. Nevertheless, interferometric length measurements performed in vacuum are much more accurate since the wavelength of the light is not affected by the air refractive index. However, compared with thermal conditions in air, in high vacuum heat conduction is missing. In such a situation, dependent on the radiative thermal equilibrium, a temperature distribution can be very inhomogeneous. Using a so-called contact gas instead of high vacuum is a very effective way to enable heat conduction on nearly the same level as under atmospheric pressure conditions whereby keeping the effect of the air refractive index on a small level. As physics predicts, and as we have demonstrated previously, helium seems like the optimal contact gas because of its large heat conduction and its refractive index that can be calculated from precisely known parameters. On the other hand, helium gas situated in a vacuum chamber could easily be contaminated, e.g. by air leakage from outside. Above the boiling point of oxygen (‑183 °C) it is therefore beneficial to use dry air as a contact gas. In such an approach, the air refractive index could be calculated based on measured quantities for pressure and temperature. However, existing formulas for the air refractive index are not valid in the low-pressure regime. Although it seems reasonable that the refractivity (n  ‑  1) of dry air simply downscales with the pressure, to our knowledge there is no experimental evidence for the applicability of any empirical formula. This evidence is given in the present paper which reports on highly accurate measurements of the air refractive index for the

Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

NASA Astrophysics Data System (ADS)

Feddema, Rick

Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

Air temperature gradient in large industrial hall

NASA Astrophysics Data System (ADS)

Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia

2017-11-01

In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

Underground storage systems for high-pressure air and gases

NASA Technical Reports Server (NTRS)

Beam, B. H.; Giovannetti, A.

1975-01-01

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

Air-broadened Lorentz halfwidths and pressure-induced line shifts in the nu(4) band of C-13H4

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Rinsland, Curtis P.; Smith, Mary Ann H.

1988-01-01

Air-broadened halfwidths and pressure-induced line shifts in the nu(4) fundamental of C-13H4 were determined from spectra recorded at room temperature and at 0.01/cm resolution using a Fourier transform spectrometer. Halfwidths and pressure shifts were determined for over 180 transitions belonging to J-double prime values of less than or = to 16. Comparisons of air-broadened halfwidths and pressure-induced line shifts made for identical transitions in the nu(4) bands of C-12H4 and C-13H4 have shown that C-13H4 air-broadened halfwidths are about 5 percent smaller than the corresponding C-12H4 halfwidths, and the pressure shifts for C-13H4 lines are about 5-15 percent larger than those for C-12H4.

Fracture Sustainability Pressure, Temperature, Differential Pressure, and Aperture Closure Data

DOE Data Explorer

Tim Kneafsey

2016-09-30

In these data sets, the experiment time, actual date and time, room temperature, sample temperature, upstream and downstream pressures (measured independently), corrected differential pressure (measured independently and corrected for offset and room temperature) indication of aperture closure by linear variable differential transformer are presented. An indication of the sample is in the file name and in the first line of data.

A temperature and pressure controlled calibration system for pressure sensors

NASA Technical Reports Server (NTRS)

Chapman, John J.; Kahng, Seun K.

1989-01-01

A data acquisition and experiment control system capable of simulating temperatures from -184 to +220 C and pressures either absolute or differential from 0 to 344.74 kPa is developed to characterize silicon pressure sensor response to temperature and pressure. System software is described that includes sensor data acquisition, algorithms for numerically derived thermal offset and sensitivity correction, and operation of the environmental chamber and pressure standard. This system is shown to be capable of computer interfaced cryogenic testing to within 1 C and 34.47 Pa of single channel or multiplexed arrays of silicon pressure sensors.

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry

PubMed Central

Holloway, Paul H.; Pritchard, David G.

2017-01-01

Abstract The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. PMID

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

Pressurized air cathodes for enhanced stability and power generation by microbial fuel cells

NASA Astrophysics Data System (ADS)

He, Weihua; Yang, Wulin; Tian, Yushi; Zhu, Xiuping; Liu, Jia; Feng, Yujie; Logan, Bruce E.

2016-11-01

Large differences between the water and air pressure in microbial fuel cells (MFCs) can deform and damage cathodes. To avoid deformation, the cathode air pressure was controlled to balance pressure differences between the air and water. Raising the air pressures from 0 to 10 kPa at a set cathode potential of -0.3 V (versus Ag/AgCl) enhanced cathode performance by 17%, but pressures ≥25 kPa decreased current and resulted in air leakage into the solution. Matching the air pressure with the water pressure avoided cathode deformation and improved performance. The maximum power density increased by 15%, from 1070 ± 20 to 1230 ± 70 mW m-2, with balanced air and water pressures of 10-25 kPa. Oxygen partial pressures ≥12.5 kPa in the cathode compartment maintained the oxygen reduction rate to be within 92 ± 1% of that in ambient air. The use of pressurized air flow through the cathode compartments can enable closer spacing of the cathodes compared to passive gas transfer systems, which could make the reactor design more compact. The energy cost of pressurizing the cathodes was estimated to be smaller than the increase in power that resulted from the use of pressurized cathodes.

A new retrieval algorithm for tropospheric temperature, humidity and pressure profiling based on GNSS radio occultation data

NASA Astrophysics Data System (ADS)

Kirchengast, Gottfried; Li, Ying; Scherllin-Pirscher, Barbara; Schwärz, Marc; Schwarz, Jakob; Nielsen, Johannes K.

2017-04-01

The GNSS radio occultation (RO) technique is an important remote sensing technique for obtaining thermodynamic profiles of temperature, humidity, and pressure in the Earth's troposphere. However, due to refraction effects of both dry ambient air and water vapor in the troposphere, retrieval of accurate thermodynamic profiles at these lower altitudes is challenging and requires suitable background information in addition to the RO refractivity information. Here we introduce a new moist air retrieval algorithm aiming to improve the quality and robustness of retrieving temperature, humidity and pressure profiles in moist air tropospheric conditions. The new algorithm consists of four steps: (1) use of prescribed specific humidity and its uncertainty to retrieve temperature and its associated uncertainty; (2) use of prescribed temperature and its uncertainty to retrieve specific humidity and its associated uncertainty; (3) use of the previous results to estimate final temperature and specific humidity profiles through optimal estimation; (4) determination of air pressure and density profiles from the results obtained before. The new algorithm does not require elaborated matrix inversions which are otherwise widely used in 1D-Var retrieval algorithms, and it allows a transparent uncertainty propagation, whereby the uncertainties of prescribed variables are dynamically estimated accounting for their spatial and temporal variations. Estimated random uncertainties are calculated by constructing error covariance matrices from co-located ECMWF short-range forecast and corresponding analysis profiles. Systematic uncertainties are estimated by empirical modeling. The influence of regarding or disregarding vertical error correlations is quantified. The new scheme is implemented with static input uncertainty profiles in WEGC's current OPSv5.6 processing system and with full scope in WEGC's next-generation system, the Reference Occultation Processing System (rOPS). Results from

Effects of oxygen partial pressure on Li-air battery performance

NASA Astrophysics Data System (ADS)

Kwon, Hyuk Jae; Lee, Heung Chan; Ko, Jeongsik; Jung, In Sun; Lee, Hyun Chul; Lee, Hyunpyo; Kim, Mokwon; Lee, Dong Joon; Kim, Hyunjin; Kim, Tae Young; Im, Dongmin

2017-10-01

For application in electric vehicles (EVs), the Li-air battery system needs an air intake system to supply dry oxygen at controlled concentration and feeding rate as the cathode active material. To facilitate the design of such air intake systems, we have investigated the effects of oxygen partial pressure (≤1 atm) on the performance of the Li-air cell, which has not been systematically examined. The amounts of consumed O2 and evolved CO2 from the Li-air cell are measured with a custom in situ differential electrochemical gas chromatography-mass spectrometry (DEGC-MS). The amounts of consumed O2 suggest that the oxygen partial pressure does not affect the reaction mechanism during discharge, and the two-electron reaction occurs under all test conditions. On the other hand, the charging behavior varies by the oxygen partial pressure. The highest O2 evolution ratio is attained under 70% O2, along with the lowest CO2 evolution. The cell cycle life also peaks at 70% O2 condition. Overall, an oxygen partial pressure of about 0.5-0.7 atm maximizes the Li-air cell capacity and stability at 1 atm condition. The findings here indicate that the appropriate oxygen partial pressure can be a key factor when developing practical Li-air battery systems.

Calibration of Relative Humidity Devices in Low-pressure, Low-temperature CO2 Environment

NASA Astrophysics Data System (ADS)

Genzer, Maria; Polkko, Jouni; Nikkanen, Timo; Hieta, Maria; Harri, Ari-Matti

2017-04-01

Calibration of relative humidity devices requires in minimum two humidity points - dry (0%RH) and (near)saturation (95-100%RH) - over the expected operational temperature and pressure range of the device. In terrestrial applications these are relatively easy to achieve using for example N2 gas as dry medium, and water vapor saturation chambers for producing saturation and intermediate humidity points. But for example in applications intended for meteorological measurements on Mars there is a need to achieve at least dry and saturation points in low-temperature, low-pressure CO2 environment. We have developed a custom-made, small, relatively low-cost calibration chamber able to produce both dry points and saturation points in Martian range pressure CO2, in temperatures down to -70°C. The system utilizes a commercially available temperature chamber for temperature control, vacuum vessels and pumps. The main pressure vessel with the devices under test inside is placed inside the temperature chamber, and the pressure inside is controlled by pumps and manual valves and monitored with a commercial pressure reference with calibration traceable to national standards. Air, CO2, or if needed another gas like N2, is used for filling the vessel until the desired pressure is achieved. Another pressure vessel with a dedicated pressure pump is used as the saturation chamber. This vessel is placed in the room outside the temperature chamber, partly filled with water and used for achieving saturated water vapor in room-temperature low-pressure environment. The saturation chamber is connected to the main pressure vessel via valves. In this system dry point, low-pressure CO2 environment is achieved by filling the main pressure vessel with dry CO2 gas until the desired pressure is achieved. A constant flow of gas is maintained with the pump and valves and monitored with the pressure reference. The saturation point is then achieved by adding some water vapor from the saturation

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

Vapor pressures of acetylene at low temperatures

NASA Technical Reports Server (NTRS)

Masterson, C. M.; Allen, John E., Jr.; Kraus, G. F.; Khanna, R. K.

1990-01-01

The atmospheres of many of the outer planets and their satellites contain a large number of hydrocarbon species. In particular, acetylene (C2H2) has been identified at Jupiter, Saturn and its satellite Titan, Uranus and Neptune. In the lower atmospheres of these planets, where colder temperatures prevail, the condensation and/or freezing of acetylene is probable. In order to obtain accurate models of the acetylene in these atmospheres, it is necessary to have a complete understanding of its vapor pressures at low temperatures. Vapor pressures at low temperatures for acetylene are being determined. The vapor pressures are measured with two different techniques in order to cover a wide range of temperatures and pressures. In the first, the acetylene is placed in a sample tube which is immersed in a low temperature solvent/liquid nitrogen slush bath whose temperature is measured with a thermocouple. The vapor pressure is then measured directly with a capacitance manometer. For lower pressures, a second technique which was called the thin-film infrared method (TFIR) was developed. It involves measuring the disappearance rate of a thin film of acetylene at a particular temperature. The spectra are then analyzed using previously determined extinction coefficient values, to determine the disappearance rate R (where R = delta n/delta t, the number of molecules that disappear per unit time). This can be related to the vapor pressure directly. This technique facilitates measurement of the lower temperatures and pressures. Both techniques have been calibrated using CO2, and have shown good agreement with the existing literature data.

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Powerplant Controls and Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

Air pressures in wood frame walls

Treesearch

Anton TenWolde; Charles G. Carll; Vyto Malinauskas

1998-01-01

Wind pressures can play an important role in the wetting of exterior walls (driving rain). In response, the rain screen concept, including compartmentalization and air spaces, has been developed to provide pressure equalization and limit water entry into the wall. However, conventional construction such as wood lap siding has not been evaluated as to its ability to...

Superconducting critical temperature under pressure

NASA Astrophysics Data System (ADS)

González-Pedreros, G. I.; Baquero, R.

2018-05-01

The present record on the critical temperature of a superconductor is held by sulfur hydride (approx. 200 K) under very high pressure (approx. 56 GPa.). As a consequence, the dependence of the superconducting critical temperature on pressure became a subject of great interest and a high number of papers on of different aspects of this subject have been published in the scientific literature since. In this paper, we calculate the superconducting critical temperature as a function of pressure, Tc(P), by a simple method. Our method is based on the functional derivative of the critical temperature with the Eliashberg function, δTc(P)/δα2F(ω). We obtain the needed coulomb electron-electron repulsion parameter, μ*(P) at each pressure in a consistent way by fitting it to the corresponding Tc using the linearized Migdal-Eliashberg equation. This method requires as input the knowledge of Tc at the starting pressure only. It applies to superconductors for which the Migdal-Eliashberg equations hold. We study Al and β - Sn two weak-coupling low-Tc superconductors and Nb, the strong coupling element with the highest critical temperature. For Al, our results for Tc(P) show an excellent agreement with the calculations of Profeta et al. which are known to agree well with experiment. For β - Sn and Nb, we found a good agreement with the experimental measurements reported in several works. This method has also been applied successfully to PdH elsewhere. Our method is simple, computationally light and gives very accurate results.

Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

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

Lee, Eun J.; Oh, Sang Youp; Kim, Ho Y.

2010-11-15

Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel's high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynoldsmore » numbers (Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A. (author)« less

Air-Cooled Heat Exchanger for High-Temperature Power Electronics: Preprint

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

Waye, S. K.; Lustbader, J.; Musselman, M.

2015-05-06

This work demonstrates a direct air-cooled heat exchanger strategy for high-temperature power electronic devices with an application specific to automotive traction drive inverters. We present experimental heat dissipation and system pressure curves versus flow rate for baseline and optimized sub-module assemblies containing two ceramic resistance heaters that provide device heat fluxes. The maximum allowable junction temperature was set to 175 deg.C. Results were extrapolated to the inverter scale and combined with balance-of-inverter components to estimate inverter power density and specific power. The results exceeded the goal of 12 kW/L and 12 kW/kg for power density and specific power, respectively.

Atomic oxygen recombination on the ODS PM 1000 at high temperature under air plasma

NASA Astrophysics Data System (ADS)

Balat-Pichelin, M.; Bêche, E.

2010-06-01

High temperature materials are necessary for the design of primary heat shields for future reusable space vehicles re-entering atmospheric planet at hypersonic velocity. During the re-entry phase on earth, one of the most important phenomena occurring on the heat shield is the recombination of atomic oxygen and this phenomenon is more or less catalyzed by the material of the heat shield. PM 1000 is planned to be use on the EXPERT capsule to study in real conditions its catalycity. Before the flight, it is necessary to perform measurements on ground test facility. Experimental data of the recombination coefficient of atomic oxygen under air plasma flow were obtained in the diffusion reactor MESOX on pre-oxidized PM 1000, for two total pressures 300 and 1000 Pa in the temperature range (850-1650 K) using actinometry and optical emission spectroscopy. In this investigation, the evolution of the recombination coefficient is dependent of temperature, pressure level and also of the chemical composition of the surface leading to one order of magnitude for a given temperature. The recombination coefficient is increasing with temperature and also dependent on the static pressure. The surface change due to the plasma exposure is inspected with SEM, XRD and XPS. As chromium oxide is the main part of the oxide layer formed during the oxidation in air plasma conditions, a sintered Cr 2O 3 sample was elaborated from powders to compare the data of the recombination coefficient obtained on PM 1000. Pre- and post-test analyses on the several materials were carried out using SEM, WDS, XRD and XPS.

Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

PubMed

Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

2017-08-25

The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

Seasonal emanation of radon at Ghuttu, northwest Himalaya: Differentiation of atmospheric temperature and pressure influences.

PubMed

Kamra, Leena

2015-11-01

Continuous monitoring of radon along with meteorological parameters has been carried out in a seismically active area of Garhwal region, northwest Himalaya, within the frame work of earthquake precursory research. Radon measurements are carried out by using a gamma ray detector installed in the air column at a depth of 10m in a 68m deep borehole. The analysis of long time series for 2006-2012 shows strong seasonal variability masked by diurnal and multi-day variations. Isolation of a seasonal cycle by minimising short-time by 31 day running average shows a strong seasonal variation with unambiguous dependence on atmospheric temperature and pressure. The seasonal characteristics of radon concentrations are positively correlated to atmospheric temperature (R=0.95) and negatively correlated to atmospheric pressure (R=-0.82). The temperature and pressure variation in their annual progressions are negatively correlated. The calculations of partial correlation coefficient permit us to conclude that atmospheric temperature plays a dominant role in controlling the variability of radon in borehole, 71% of the variability in radon arises from the variation in atmospheric temperature and about 6% of the variability is contributed by atmospheric pressure. The influence of pressure variations in an annual cycle appears to be a pseudo-effect, resulting from the negative correlation between temperature and pressure variations. Incorporation of these results explains the varying and even contradictory claims regarding the influence of the pressure variability on radon changes in the published literature. Temperature dependence, facilitated by the temperature gradient in the borehole, controls the transportation of radon from the deep interior to the surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

Air Pressure Responses to Sudden Vocal Tract Pressure Bleeds During Production of Stop Consonants: New Evidence of Aeromechanical Regulation

PubMed Central

Zajac, David J.; Weissler, Mark C.

2011-01-01

Two studies were conducted to evaluate short-latency vocal tract air pressure responses to sudden pressure bleeds during production of voiceless bilabial stop consonants. It was hypothesized that the occurrence of respiratory reflexes would be indicated by distinct patterns of responses as a function of bleed magnitude. In Study 1, 19 adults produced syllable trains of /pΛ/ using a mouthpiece coupled to a computer-controlled perturbator. The device randomly created bleed apertures that ranged from 0 to 40 mm2 during production of the 2nd or 4th syllable of an utterance. Although peak oral air pressure dropped in a linear manner across bleed apertures, it averaged 2 to 3 cm H2O at the largest bleed. While slope of oral pressure also decreased in a linear trend, duration of the oral pressure pulse remained relatively constant. The patterns suggest that respiratory reflexes, if present, have little effect on oral air pressure levels. In Study 2, both oral and subglottal air pressure responses were monitored in 2 adults while bleed apertures of 20 and 40 mm2 were randomly created. For 1 participant, peak oral air pressure dropped across bleed apertures, as in Study 1. Subglottal air pressure and slope, however, remained relatively stable. These patterns provide some support for the occurrence of respiratory reflexes to regulate subglottal air pressure. Overall, the studies indicate that the inherent physiologic processes of the respiratory system, which may involve reflexes, and passive aeromechanical resistance of the upper airway are capable of developing oral air pressure in the face of substantial pressure bleeds. Implications for understanding speech production and the characteristics of individuals with velopharyngeal dysfunction are discussed. PMID:15324286

Method and Apparatus for Measuring Surface Air Pressure

NASA Technical Reports Server (NTRS)

Lin, Bing (Inventor); Hu, Yongxiang (Inventor)

2014-01-01

The present invention is directed to an apparatus and method for remotely measuring surface air pressure. In one embodiment, the method of the present invention utilizes the steps of transmitting a signal having multiple frequencies into the atmosphere, measuring the transmitted/reflected signal to determine the relative received power level of each frequency and then determining the surface air pressure based upon the attenuation of the transmitted frequencies.

Direct current plasma jet at atmospheric pressure operating in nitrogen and air

NASA Astrophysics Data System (ADS)

Deng, X. L.; Nikiforov, A. Yu.; Vanraes, P.; Leys, Ch.

2013-01-01

An atmospheric pressure direct current (DC) plasma jet is investigated in N2 and dry air in terms of plasma properties and generation of active species in the active zone and the afterglow. The influence of working gases and the discharge current on plasma parameters and afterglow properties are studied. The electrical diagnostics show that discharge can be sustained in two different operating modes, depending on the current range: a self-pulsing regime at low current and a glow regime at high current. The gas temperature and the N2 vibrational temperature in the active zone of the jet and in the afterglow are determined by means of emission spectroscopy, based on fitting spectra of N2 second positive system (C3Π-B3Π) and the Boltzmann plot method, respectively. The spectra and temperature differences between the N2 and the air plasma jet are presented and analyzed. Space-resolved ozone and nitric oxide density measurements are carried out in the afterglow of the jet. The density of ozone, which is formed in the afterglow of nitrogen plasma jet, is quantitatively detected by an ozone monitor. The density of nitric oxide, which is generated only in the air plasma jet, is determined by means of mass-spectroscopy techniques.

[The effects of work in an air-conditioned cabin and stay in a resting chamber on blood pressure and heart rate of operators employed in deep copper mines].

PubMed

Borodulin-Nadzieja, L; Janocha, A; Pietraszkiewicz, T; Salomon, E; Stańda, M

2001-01-01

This paper is part of a wider comparative study of the heart rate, blood pressure, external and core temperature in operators of self-propelled mining machines with and without air-conditioning cabins. Two groups, each of ten operators, characterised by the similar age and duration of employment, stayed for 20 min a specially prepared resting chamber with much more advantageous microclimatic conditions. The results of our examinations (Holter heart rate and continuous blood pressure recordings, external and core temperature measurements) revealed that during the work (particularly during the increased work-load) all parameters recorded were significantly lower in air-conditioning cabins as compared with the group working without air-condition. In both groups, a complete restitution of the heart rate and blood pressure was observed after a 20-min stay in the resting chamber. During the work, a statistically significant increase in the external temperature was found in both groups of operators, whereas the increase in the core temperature was observed only in operators working without air-condition. After a 20-min stay in the resting chamber, a complete return to the normal temperature was noted only in operators working in air-conditioned cabins.

[Effect of subglottic air insufflation on subglottic pressure during swallowing].

PubMed

Clarett, M; Andreu, M F; Salvati, I G; Donnianni, M C; Montes, G S; Rodríguez, M G

2014-04-01

To determine whether there are differences between subglottic pressure during swallowing with and without air insufflation via a subglottic catheter in tracheostomized patients. A prospective, randomized cross-over study was made. Adult Intensive Care Units. Patients requiring mechanical ventilation and tracheostomy with a subglottic catheter, and with tolerance to deflation of the balloon and a speaking valve placed over the opening of the tracheostomy tube. Subglottic pressure was measured during swallowing of a thickened solution with and without the delivery of airflow through the subglottic catheter. Subglottic pressure during swallowing. Twelve out of 14 patients showed higher subglottic pressure values during swallowing with air insufflation. Two patients showed no differences between both conditions. Median (Med) values of subglottic pressure for the first, second and third swallow were 5, 4 and 4.5 cmH2O (Med 4.5 cmH2O) without air insufflation, and 8, 5.5 and 7.5 cmH2O (Med 5.5 cmH2O) with air insufflation, respectively (Wilcoxon, Z=-3.078; p=.002). In a group of tracheostomized patients, air insufflation via a subglottic catheter increased subglottic pressure levels measured during swallowing. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Heat transfer and pressure drop for air flow through enhanced passages

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

Obot, N.T.; Esen, E.B.

1992-06-01

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effectmore » depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.« less

A Lithium-Air Battery Stably Working at High Temperature with High Rate Performance.

PubMed

Pan, Jian; Li, Houpu; Sun, Hao; Zhang, Ye; Wang, Lie; Liao, Meng; Sun, Xuemei; Peng, Huisheng

2018-02-01

Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium-air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium-air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium-air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium-air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium-air battery can work stably at 140 °C with a high specific current of 10 A g -1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high-performance energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hospital-acquired pressure ulcer prevalence--evaluating low-air-loss beds.

PubMed

Johnson, Jane; Peterson, Darcie; Campbell, Betty; Richardson, Regina; Rutledge, Dana

2011-01-01

Higher-category pressure redistribution mattresses are considered a critical component of a pressure ulcer prevention program, but few studies have quantified the impact of specific preventive measures on the incidence or prevalence of hospital-acquired pressure ulcers (HAPUs). Therefore, this study was undertaken to determine the impact of low-air-loss beds on HAPU prevalence. This prospective, comparative cohort study monitored the prevalence of HAPU at our hospital and compared rates of matched medical-surgical units with and without low-air-loss beds. Units without low-air-loss beds used a variety of alternative pressure redistribution devices for patients deemed at risk for pressure ulceration. The prevalence of HAPU was operationally defined as the number of patients with HAPUs divided by numbers of patients observed. The prevalence of HAPU over 3 quarters in 2008 ranged from 1.0% to 3.3% (overall rate 2.4%). Eighty-three percent of patients with HAPUs were cared for on low-air-loss beds. Of 12 patients with 16 HAPUs during this time, 75% were aged 70 years or older and 25% were managed in critical care units. Over half of patients who developed HAPUs had been hospitalized for 20 days or more. Half of the patients with HAPUs were scored as no-low risk on the Braden Scale.On the paired medical-surgical units, no statistically significant differences were found when patients with low-air-loss beds were compared to standard hospital mattresses supplemented by a variety of pressure redistribution devices. Seven of 11 HAPUs (63%) occurred in patients placed on low-air-loss beds. The prevalence of HAPU in patients placed on low-air-loss beds was no different from patients placed on standard hospital mattresses supplemented by a variety of pressure redistribution devices. Further research is needed to determine the impact of specific strategies on prevention of HAPU.

Ambient air pollution exposure and blood pressure changes during pregnancy

PubMed Central

Lee, Pei-Chen; Talbott, Evelyn O.; Roberts, James M.; Catov, Janet M.; Bilonick, Richard A.; Stone, Roslyn A.; Sharma, Ravi K.; Ritz, Beate

2013-01-01

Background Maternal exposure to ambient air pollution has been associated with adverse birth outcomes such as preterm delivery. However, only one study to date has linked air pollution to blood pressure changes during pregnancy, a period of dramatic cardiovascular function changes. Objectives We examined whether maternal exposures to criteria air pollutants, including particles of less than 10 µm (PM10) or 2.5 µm diameter (PM2.5), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3), in each trimester of pregnancy are associated with magnitude of rise of blood pressure between the first 20 weeks of gestation and late pregnancy in a prospectively followed cohort of 1684 pregnant women in Allegheny County, PA. Methods Air pollution measures for maternal ZIP code areas were derived using Kriging interpolation. Using logistic regression analysis, we evaluated the associations between air pollution exposures and blood pressure changes between the first 20 weeks of gestation and late pregnancy. Results First trimester PM10 and ozone exposures were associated with blood pressure changes between the first 20 weeks of gestation and late pregnancy, most strongly in non-smokers. Per interquartile increases in first trimester PM10 and O3 concentrations were associated with mean increases in systolic blood pressure of 1.88 mmHg (95% CI = 0.84 to 2.93) and 1.84 (95% CI = 1.05 to 4.63), respectively, and in diastolic blood pressure of 0.63 mmHg (95% CI= −0.50 to 1.76) and 1.13 (95% CI= −0.46 to 2.71) in non-smokers. Conclusions Our novel finding suggests that first trimester PM10 and O3 air pollution exposures increase blood pressure in the later stages of pregnancy. These changes may play a role in mediating the relationships between air pollution and adverse birth outcomes. PMID:22835955

Low-temperature forced-air drying of Appalachian hardwoods

Treesearch

Donald G. Cuppett; E. Paul Craft

1975-01-01

Low-temperature forced-air drying involves drying green lumber in heated buildings with forced-air circulation and partial control of temperature and humidity conditions. The lumber is dried to about 20 percent moisture content at dry-bulb temperatures of 70º to 110ºF and with air velocities of 300 to 600 feet per minute. Equipment, methods, and...

The Influence of Shaping Air Pressure of Pneumatic Spray Gun

NASA Astrophysics Data System (ADS)

Chen, Wenzhuo; Chen, Yan; Pan, Haiwei; Zhang, Weiming; Li, Bo

2018-02-01

The shaping air pressure is a very important parameter in the application of pneumatic spray gun, and studying its influence on spray flow field and film thickness distribution has practical values. In this paper, Euler-Lagrangian method is adopted to describe the two-phase spray flow of pneumatic painting process, and the air flow fields, spray patterns and dynamic film thickness distributions were obtained with the help of the computational fluid dynamics code—ANSYS Fluent. Results show that with the increase of the shaping air pressure, the air phase flow field spreads in the plane perpendicular to the shaping air hole plane, the spray pattern becomes narrower and flatter, and the width of the dynamic film increases with the reduced maximum value of the film thickness. But the film thickness distribution seems to change little with the shaping air pressure decreasing from 0.6bar to 0.9bar.

Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

NASA Technical Reports Server (NTRS)

Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

2014-01-01

The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

Ultrahigh Temperature Capacitive Pressure Sensor

NASA Technical Reports Server (NTRS)

Harsh, Kevin

2014-01-01

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

Pure rotational CARS thermometry studies of low-temperature oxidation kinetics in air and ethene-air nanosecond pulse discharge plasmas

NASA Astrophysics Data System (ADS)

Zuzeek, Yvette; Choi, Inchul; Uddi, Mruthunjaya; Adamovich, Igor V.; Lempert, Walter R.

2010-03-01

Pure rotational CARS thermometry is used to study low-temperature plasma assisted fuel oxidation kinetics in a repetitive nanosecond pulse discharge in ethene-air at stoichiometric and fuel lean conditions at 40 Torr pressure. Air and fuel-air mixtures are excited by a burst of high-voltage nanosecond pulses (peak voltage, 20 kV; pulse duration, ~ 25 ns) at a 40 kHz pulse repetition rate and a burst repetition rate of 10 Hz. The number of pulses in the burst is varied from a few pulses to a few hundred pulses. The results are compared with the previously developed hydrocarbon-air plasma chemistry model, modified to incorporate non-empirical scaling of the nanosecond discharge pulse energy coupled to the plasma with number density, as well as one-dimensional conduction heat transfer. Experimental time-resolved temperature, determined as a function of the number of pulses in the burst, is found to agree well with the model predictions. The results demonstrate that the heating rate in fuel-air plasmas is much faster compared with air plasmas, primarily due to energy release in exothermic reactions of fuel with O atoms generated by the plasma. It is found that the initial heating rate in fuel-air plasmas is controlled by the rate of radical (primarily O atoms) generation and is nearly independent of the equivalence ratio. At long burst durations, the heating rate in lean fuel air-mixtures is significantly reduced when all fuel is oxidized.

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.

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry.

PubMed

Holloway, Paul H; Pritchard, David G

2017-08-01

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. © The Author 2017

Compressed air injection technique to standardize block injection pressures.

PubMed

Tsui, Ban C H; Li, Lisa X Y; Pillay, Jennifer J

2006-11-01

Presently, no standardized technique exists to monitor injection pressures during peripheral nerve blocks. Our objective was to determine if a compressed air injection technique, using an in vitro model based on Boyle's law and typical regional anesthesia equipment, could consistently maintain injection pressures below a 1293 mmHg level associated with clinically significant nerve injury. Injection pressures for 20 and 30 mL syringes with various needle sizes (18G, 20G, 21G, 22G, and 24G) were measured in a closed system. A set volume of air was aspirated into a saline-filled syringe and then compressed and maintained at various percentages while pressure was measured. The needle was inserted into the injection port of a pressure sensor, which had attached extension tubing with an injection plug clamped "off". Using linear regression with all data points, the pressure value and 99% confidence interval (CI) at 50% air compression was estimated. The linearity of Boyle's law was demonstrated with a high correlation, r = 0.99, and a slope of 0.984 (99% CI: 0.967-1.001). The net pressure generated at 50% compression was estimated as 744.8 mmHg, with the 99% CI between 729.6 and 760.0 mmHg. The various syringe/needle combinations had similar results. By creating and maintaining syringe air compression at 50% or less, injection pressures will be substantially below the 1293 mmHg threshold considered to be an associated risk factor for clinically significant nerve injury. This technique may allow simple, real-time and objective monitoring during local anesthetic injections while inherently reducing injection speed.

Tongue-Palate Contact Pressure, Oral Air Pressure, and Acoustics of Clear Speech

ERIC Educational Resources Information Center

Searl, Jeff; Evitts, Paul M.

2013-01-01

Purpose: The authors compared articulatory contact pressure (ACP), oral air pressure (Po), and speech acoustics for conversational versus clear speech. They also assessed the relationship of these measures to listener perception. Method: Twelve adults with normal speech produced monosyllables in a phrase using conversational and clear speech.…

An alternating pressure sequence proposal for an air-cell cushion for preventing pressure ulcers.

PubMed

Arias, Sandra; Cardiel, Eladio; Rogeli, Pablo; Mori, Taketoshi; Nakagami, Gojiro; Noguchi, Hiroshi; Sanada, Hiromi

2014-01-01

The distribution and release of pressure on ischial regions are two important parameters for evaluating the effectiveness of a cushion; especially the release of pressure over time on ischial tuberosities, which is significant for preventing pressure ulcers. The aim of this work is to evaluate the effect on interface pressure through the application of a proposed alternating pressure sequence for an air-cell cushion. Six healthy volunteers were asked to sit on the air cell cushion, in static and alternating modes, as well as on a typical foam cushion for 12 minutes. Interface pressure was monitored with a matrix sensor system. Interface pressure values on ischial tuberosities, user contact area and pressure distribution were analyzed. Results showed that IP on IT tends to increase in both foam and static cushions, while in alternating cushion IP on IT tends to decrease. User contact area was significantly larger in alternating cushion than in static or foam cushions. Moreover, there is a better pressure re-distribution with alternating cushion than with the other cushions. The goal of the alternating sequence is to redistribute pressure and stimulate the ischial regions in order to promote blood flow and prevent pressure occurring in wheelchair users.

Use of Quality Controlled AIRS Temperature Soundings to Improve Forecast Skill

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste; Iredell, Lena

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. Also included are the clear column radiances used to derive these products which are representative of the radiances AIRS would have seen if there were no clouds in the field of view. All products also have error estimates. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1K, and layer precipitable water with an rms error of 20 percent, in cases with up to 90 percent effective cloud cover. The products are designed for data assimilation purposes for the improvement of numerical weather prediction, as well as for the study of climate and meteorological processes. With regard to data assimilation, one can use either the products themselves or the clear column radiances from which the products were derived. The AIRS Version 5 retrieval algorithm is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates for retrieved quantities and clear column radiances, and the use of these error estimates for Quality Control. The temperature profile error estimates are used to determine a case-by-case characteristic pressure pbest, down to which the profile is considered acceptable for data assimilation purposes. The characteristic pressure p(sub best) is determined by comparing the case dependent error estimate (delta)T(p) to the threshold values (Delta)T(p). The AIRS Version 5 data set provides error estimates of T(p) at all levels, and also profile dependent values of pbest based

Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

NASA Technical Reports Server (NTRS)

Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

2010-01-01

Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

Development and evaluation of a self-regulating alternating pressure air cushion.

PubMed

Nakagami, Gojiro; Sanada, Hiromi; Sugama, Junko

2015-03-01

To investigate the effect of alternating air cells of a newly developed dynamic cushion on interface pressure and tissue oxygenation levels. This cross-over experimental study included 19 healthy volunteers. The dynamic cushion used has an automatic self-regulating alternating pressure air-cell system with 35 small and four large air cells for maintaining posture while seated. This cushion also has 17 bottoming-out detectors that automatically inflate the air cells to release a high interface pressure. To assess the effect of this alternating system, participants sat on the new cushion with an alternating system or static system for 30 min and then performed push-ups. The interface pressure was monitored by pressure-sensitive and conductive ink film sensors and tissue oxygenation levels were monitored by near-infrared spectroscopy. A reactive hyperaemia indicator was calculated using tissue oxygenation levels as an outcome measure. The peak interface pressure was not significantly different between the groups. The reactive hyperaemia indicator was significantly higher in the static group than in the alternating group. An alternating system has beneficial effects on blood oxygenation levels without increasing interface pressure. Therefore, our new cushion is promising for preventing pressure ulcers with patients with limited ability to perform push-ups. Implications for Rehabilitation A dynamic cushion was developed, which consists of a uniquely-designed air-cell layout, detectors for bottoming out, and an alternating system with multiple air-cell lines. The alternating system did not increase interface pressure and it significantly reduced reactive hyperaemia after 30 min of sitting in healthy volunteers. This cushion is a new option for individuals who require stable posture but have limitations in performing scheduled push-ups for prevention of pressure ulcers.

AIRS Retrieved Temperature Isotherms over Southern Europe

NASA Image and Video Library

2002-09-08

AIRS Retrieved Temperature Isotherms over Southern Europe viewed from the west, September 8, 2002. The isotherms in this map made from AIRS onboard NASA Aqua satellite data show regions of the same temperature in the atmosphere. http://photojournal.jpl.nasa.gov/catalog/PIA00513

Oxygen-Rich Lithium Oxide Phases Formed at High Pressure for Potential Lithium-Air Battery Electrode.

PubMed

Yang, Wenge; Kim, Duck Young; Yang, Liuxiang; Li, Nana; Tang, Lingyun; Amine, Khalil; Mao, Ho-Kwang

2017-09-01

The lithium-air battery has great potential of achieving specific energy density comparable to that of gasoline. Several lithium oxide phases involved in the charge-discharge process greatly affect the overall performance of lithium-air batteries. One of the key issues is linked to the environmental oxygen-rich conditions during battery cycling. Here, the theoretical prediction and experimental confirmation of new stable oxygen-rich lithium oxides under high pressure conditions are reported. Three new high pressure oxide phases that form at high temperature and pressure are identified: Li 2 O 3 , LiO 2 , and LiO 4 . The LiO 2 and LiO 4 consist of a lithium layer sandwiched by an oxygen ring structure inherited from high pressure ε-O 8 phase, while Li 2 O 3 inherits the local arrangements from ambient LiO 2 and Li 2 O 2 phases. These novel lithium oxides beyond the ambient Li 2 O, Li 2 O 2 , and LiO 2 phases show great potential in improving battery design and performance in large battery applications under extreme conditions.

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

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Portable air receivers and other unfired pressure vessels... SHIPYARD EMPLOYMENT Portable, Unfired Pressure Vessels, Drums and Containers, Other Than Ship's Equipment § 1915.172 Portable air receivers and other unfired pressure vessels. (a) Portable, unfired pressure...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Portable air receivers and other unfired pressure vessels... SHIPYARD EMPLOYMENT Portable, Unfired Pressure Vessels, Drums and Containers, Other Than Ship's Equipment § 1915.172 Portable air receivers and other unfired pressure vessels. (a) Portable, unfired pressure...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Portable air receivers and other unfired pressure vessels... SHIPYARD EMPLOYMENT Portable, Unfired Pressure Vessels, Drums and Containers, Other Than Ship's Equipment § 1915.172 Portable air receivers and other unfired pressure vessels. (a) Portable, unfired pressure...

Fuel Cells Utilizing Oxygen From Air at Low Pressures

NASA Technical Reports Server (NTRS)

Cisar, Alan; Boyer, Chris; Greenwald, Charles

2006-01-01

A fuel cell stack has been developed to supply power for a high-altitude aircraft with a minimum of air handling. The fuel cell is capable of utilizing oxygen from ambient air at low pressure with no need for compression. For such an application, it is advantageous to take oxygen from the air (in contradistinction to carrying a supply of oxygen onboard), but it is a challenging problem to design a fuel-cell stack of reasonable weight that can generate sufficient power while operating at reduced pressures. The present fuel-cell design is a response to this challenge. The design features a novel bipolar plate structure in combination with a gas-diffusion structure based on a conductive metal core and a carbon gas-diffusion matrix. This combination makes it possible for the flow fields in the stack to have a large open fraction (ratio between open volume and total volume) to permit large volumes of air to flow through with exceptionally low backpressure. Operations at reduced pressure require a corresponding increase in the volume of air that must be handled to deliver the same number of moles of oxygen to the anodes. Moreover, the increase in the open fraction, relative to that of a comparable prior fuel-cell design, reduces the mass of the stack. The fuel cell has been demonstrated to operate at a power density as high as 105 W/cm2 at an air pressure as low as 2 psia (absolute pressure 14 kPa), which is the atmospheric pressure at an altitude of about 50,000 ft ( 15.2 km). The improvements in the design of this fuel cell could be incorporated into designs of other fuel cells to make them lighter in weight and effective at altitudes higher than those of prior designs. Potential commercial applications for these improvements include most applications now under consideration for fuel cells.

Thermoelectric Control Of Temperatures Of Pressure Sensors

NASA Technical Reports Server (NTRS)

Burkett, Cecil G., Jr.; West, James W.; Hutchinson, Mark A.; Lawrence, Robert M.; Crum, James R.

1995-01-01

Prototype controlled-temperature enclosure containing thermoelectric devices developed to house electronically scanned array of pressure sensors. Enclosure needed because (1) temperatures of transducers in sensors must be maintained at specified set point to ensure proper operation and calibration and (2) sensors sometimes used to measure pressure in hostile environments (wind tunnels in original application) that are hotter or colder than set point. Thus, depending on temperature of pressure-measurement environment, thermoelectric devices in enclosure used to heat or cool transducers to keep them at set point.

Combustion efficiency determined from wall pressure and temperature measurement in a Mach 2 combustor

NASA Technical Reports Server (NTRS)

Segal, Corin; Mcdaniel, James C.; Whitehurst, Robert B.; Krauss, Roland H.

1991-01-01

A study of transverse hydrogen injection behind a rearward facing step in a Mach 2 airflow was conducted to determine the combustion efficiency and the combustor/inlet interactions at the low temperature lean-mixture operational end of a scramjet combustor model. The fuel was injected at sonic conditions into the electrically heated airstream, which was maintained at 850 K or below. The static pressure delivered at the entrance of the combustor ranged between 0.25 to 0.5 atm. Injector configurations included single and staged injectors placed at 3 or 3-and-7 step-heights downstream of the step, respectively, with injector diameters of 1, 1.5, and 2 mm. Ignition was achieved by initially unstarting the test section. The constant area combustor and the low initial temperatures caused thermal choking and upstream interaction to occur at very low equivalence ratios. Typically, most of the fuel was burned in the recirculation region behind the step and around the jets. The effects of initial conditions (temperature and pressure), fuel-to-air dynamic pressure ratio, and boundaries (thermal vs adiabatic) are presented.

Degradation of cationic red GTL by catalytic wet air oxidation over Mo-Zn-Al-O catalyst under room temperature and atmospheric pressure.

PubMed

Xu, Yin; Li, Xiaoyi; Cheng, Xiang; Sun, Dezhi; Wang, Xueye

2012-03-06

To overcome the drawback of catalytic wet air oxidation (CWAO) with high temperature and high pressure, the catalytic activity of Mo-Zn-Al-O catalyst for degradation of cationic red GTL under room temperature and atmospheric pressure was investigated. Mo-Zn-Al-O catalyst was prepared by coprecipitation and impregnation. XRD, TG-DTG, and XPS were used to characterize the resulting sample. Central composition design using response surface methodology was employed to optimize correlation of factors on the decolorization of cationic red GTL. The results show that the optimal conditions of pH value, initial concentration of dye and catalyst dosage were found to be 4.0, 85 mg/L and 2.72 g/L, respectively, for maximum decolorization of 80.1% and TOC removal of 50.9%. Furthermore, the reaction on the Mo-Zn-Al-O catalyst and degradation mechanism of cationic red GTL was studied by Electron spin resonance (ESR) and GC-MS technique. The possible reaction mechanism was that the Mo-Zn-Al-O catalyst can efficiently react with adsorbed oxygen/H(2)O to produce ·OH and (1)O(2) and finally induce the degradation of cationic red GTL. GC-MS analysis of the degradation products indicates that cationic red GTL was initiated by the cleavage of -N ═ N- and the intermediates were further oxidized by ·OH or (1)O(2).

Design and preliminary results of a semitranspiration cooled (Lamilloy) liner for a high-pressure high-temperature combustor

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jones, R. E.

1978-01-01

A Lamilloy combustor liner was designed, fabricated and tested in a combustor at pressures up to 8 atmospheres. The liner was fabricated of a three layer Lamilloy structure and designed to replace a conventional step louver liner. The liner is to be used in a combustor that provides hot gases to a turbine cooling test facility at pressures up to 40 atmospheres. The Lamilloy liner was tested extensively at lower pressures and demonstrated lower metal temperatures than the conventional liner, while at the same time requiring about 40 percent less cooling air flow. Tests conducted at combustor exit temperatures in excess of 2200 K have not indicated any cooling or durability problems with the Lamilloy linear.

Isolating Gas Sensor From Pressure And Temperature Effects

NASA Technical Reports Server (NTRS)

Sprinkle, Danny R.; Chen, Tony T. D.; Chaturvedi, Sushi K.

1994-01-01

Two-stage flow system enables oxygen sensor in system to measure oxygen content of low-pressure, possibly-high-temperature atmosphere in test environment while protecting sensor against possibly high temperature and fluctuations in pressure of atmosphere. Sensor for which flow system designed is zirconium oxide oxygen sensor sampling atmospheres in high-temperature wind tunnels. Also adapted to other gas-analysis instruments that must be isolated from pressure and temperature effects of test environments.

40 CFR 89.325 - Engine intake air temperature measurement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made either...

40 CFR 89.325 - Engine intake air temperature measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made either...

40 CFR 89.325 - Engine intake air temperature measurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made either...

40 CFR 89.325 - Engine intake air temperature measurement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made either...

Elasticity of Unquenchable High-Pressure Clinopyroxene at High Pressures and Temperatures

NASA Astrophysics Data System (ADS)

Kung, J.; Li, B.; Uchida, T.; Wang, Y.

2003-12-01

A phase transformation in (Mg,Fe)SiO3, one of the common constituent of the Earth's crust and upper mantle, from orthorhombic (OEN) to monoclinic symmetry is likely to occur in the deeper portions of the upper mantle (Pacalo and Gasparik, 1990; Kanzaki, 1991). Angel et al. (1992) confirmed that the clinoenstatite phase above 8 GPa is an unquenchable high pressure monoclinic phase (HP-CEN), space group C2/c. Due to its unquenchable nature, this high pressure clinoenstatite has to be synthesized within its stability field in order to study its elasticity. The elasticity measurements were carried out using the ultrasonic technique in the large volume apparatus in conjunction with in-situ X-radiation techniques (X-ray diffraction and X-radiography). The experimental setup has made possible to monitor the length change of sample during experiment, as well as the measurements of travel times and density of the sample simultaneously. The starting material for the acoustic experiment was a well-sintered OEN polycrystalline specimen, which was hot-pressed at conditions of 5 GPa, 1000 degree C for an hour prior the experiment. After the OEN fully transformed to the HP-CEN at pressure of 13 GPa, 1000 degree C during the acoustic experiment, elasticity and X-ray data have been collected along a series of heating/cooling cycles at different pressures during the decompression. The data collection was stopped at 6.5 GPa because of the phase transition from HP-CEN to LP-CEN at lower pressure. The resulting bulk and shear moduli at different P-T conditions were treated as linear functions of both pressure and temperature with adjustable parameters: moduli at 6.5 GPa, room temperature, the pressure derivatives at constant temperatures, and the temperature derivatives at constant pressures. Compared with OEN (Flesch et al., 1998), our results show that the pressure derivatives of the bulk and shear moduli of HP-CEN are similar to those of OEN when the conditions of 6.5 GPa, room

Computer program for obtaining thermodynamic and transport properties of air and products of combustion of ASTM-A-1 fuel and air

NASA Technical Reports Server (NTRS)

Hippensteele, S. A.; Colladay, R. S.

1978-01-01

A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (or enthalpy), molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, isentropic exponent (equal to the specific heat ratio at conditions where gases do not react), Prandtl number, and entropy for air and a combustion gas mixture of ASTM-A-1 fuel and air over fuel-air ratios from zero to stoichiometric, pressures from 1 to 40 atm, and temperatures from 250 to 2800 K.

40 CFR 89.325 - Engine intake air temperature measurement.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature measurement. 89.325 Section 89.325 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air...

Temperature compensated high-temperature/high-pressure Merrill--Bassett diamond anvil cell

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

Schiferl, D.

1987-07-01

A Merrill--Bassett diamond anvil cell for high-temperature/high-pressure studies up to 5 GPa at 1000 K and 13 GPa at 725 K is described. To maintain uniform, well-characterized temperatures, and to protect the diamond anvils from oxidation and graphitization, the entire cell is heated in a vacuum oven. The materials are chosen so that the pressure remains constant to within +-10% over the entire temperature range.

On the Experimental and Theoretical Investigations of Lean Partially Premixed Combustion, Burning Speed, Flame Instability and Plasma Formation of Alternative Fuels at High Temperatures and Pressures

NASA Astrophysics Data System (ADS)

Askari, Omid

This dissertation investigates the combustion and injection fundamental characteristics of different alternative fuels both experimentally and theoretically. The subjects such as lean partially premixed combustion of methane/hydrogen/air/diluent, methane high pressure direct-injection, thermal plasma formation, thermodynamic properties of hydrocarbon/air mixtures at high temperatures, laminar flames and flame morphology of synthetic gas (syngas) and Gas-to-Liquid (GTL) fuels were extensively studied in this work. These subjects will be summarized in three following paragraphs. The fundamentals of spray and partially premixed combustion characteristics of directly injected methane in a constant volume combustion chamber have been experimentally studied. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a Compressed Natural Gas (CNG) Direct-Injection (DI) engines. The effect of different characteristics parameters such as spark delay time, stratification ratio, turbulence intensity, fuel injection pressure, chamber pressure, chamber temperature, Exhaust Gas recirculation (EGR) addition, hydrogen addition and equivalence ratio on flame propagation and emission concentrations were analyzed. As a part of this work and for the purpose of control and calibration of high pressure injector, spray development and characteristics including spray tip penetration, spray cone angle and overall equivalence ratio were evaluated under a wide range of fuel injection pressures of 30 to 90 atm and different chamber pressures of 1 to 5 atm. Thermodynamic properties of hydrocarbon/air plasma mixtures at ultra-high temperatures must be precisely calculated due to important influence on the flame kernel formation and propagation in combusting flows and spark discharge applications. A new algorithm based on the statistical thermodynamics was developed to calculate the ultra-high temperature plasma

The effect of nozzle diameter, injection pressure and ambient temperature on spray characteristics in diesel engine

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Multi-hole pressure probes to air data system for subsonic small-scale air vehicles

NASA Astrophysics Data System (ADS)

Shevchenko, A. M.; Berezin, D. R.; Puzirev, L. N.; Tarasov, A. Z.; Kharitonov, A. M.; Shmakov, A. S.

2016-10-01

A brief review of research performed to develop multi-hole probes to measure of aerodynamic angles, dynamic head, and static pressure of a flying vehicle. The basis of these works is the application a well-known classical multi-hole pressure probe technique of measuring of a 3D flow to use in the air data system. Two multi-hole pressure probes with spherical and hemispherical head to air-data system for subsonic small-scale vehicles have been developed. A simple analytical probe model with separation of variables is proposed. The probes were calibrated in the wind tunnel, one of them is in-flight tested.

Estimating past leaf-to-air vapour pressure deficit from terrestrial plant 13C

NASA Astrophysics Data System (ADS)

Turney, Chris S. M.; Barringer, James; Hunt, John E.; McGlone, Matt S.

1999-08-01

13C was determined in lignin extracted from present-day cladodes of Phyllocladus alpinus (a small coniferous tree) from seven well-lit sites across New Zealand. The 13C values ranged from -30.9 to -23.6 and were compared with monthly means of temperature, precipitation, relative humidity and vapour pressure deficit from the nearest recording stations. Of these parameters, the leaf-to-air vapour pressure deficit of the first month of cladode growth and expansion proved to be the most significantly correlated with lignin 13C, over a range of 0.3 to 0.8 kPa, confirming the importance of atmospheric moisture content on stomatal conductance. The carbon isotopic signature of lignin from fossilised cladodes preserved under the Kawakawa Tephra (22.6 k 14C yr BP) on the North Island is identical to that of the whole tissue, suggesting that for this species at least, fossil material can be used to approximate the lignin 13C. The 13C of species- and organ-specific fossil terrestrial plant material therefore provides an excellent method to quantify past changes in leaf-to-air vapour pressure deficit.

Temperature measurements behind reflected shock waves in air. [radiometric measurement of gas temperature in self-absorbing gas flow

NASA Technical Reports Server (NTRS)

Bader, J. B.; Nerem, R. M.; Dann, J. B.; Culp, M. A.

1972-01-01

A radiometric method for the measurement of gas temperature in self-absorbing gases has been applied in the study of shock tube generated flows. This method involves making two absolute intensity measurements at identical wavelengths, but for two different pathlengths in the same gas sample. Experimental results are presented for reflected shock waves in air at conditions corresponding to incident shock velocities from 7 to 10 km/s and an initial driven tube pressure of 1 torr. These results indicate that, with this technique, temperature measurements with an accuracy of + or - 5 percent can be carried out. The results also suggest certain facility related problems.

Pressure and temperature interactions on cellular respiration: a review.

PubMed

Sebert, P; Theron, M; Vettier, A

2004-06-01

Thermodynamic equations show that pressure and temperature can, theoretically, act in synergy or in opposite directions depending on their respective variations. Hence, they interact to establish rates of biological processes (pressure/temperature interactions, PTI). For such studies, it is interesting to use aquatic ectotherms, in particular fish, because it is easy to submit them to temperature and/or pressure changes. This review focuses on the effects of temperature and pressure changes on the energy metabolism of fish, mitochondrial oxygen consumption and functioning, showing that the observed effects do not always match the predictions made by equations or models. Unpublished results concerning the mitochondrial function of eels acclimatised at two temperatures and two pressures show that the mitochondrial targets of pressure and temperature are probably not the same. The possible mechanisms and consequences of PTI are discussed.

Pressure, temperature and density drops along supercritical fluid chromatography columns in different thermal environments. III. Mixtures of carbon dioxide and methanol as the mobile phase.

PubMed

Poe, Donald P; Veit, Devon; Ranger, Megan; Kaczmarski, Krzysztof; Tarafder, Abhijit; Guiochon, Georges

2014-01-03

The pressure, temperature and density drops along SFC columns eluted with a CO2/methanol mobile phase were measured and compared with theoretical values. For columns packed with 3- and 5-μm particles the pressure and temperature drops were measured using a mobile phase of 95% CO2 and 5% methanol at a flow rate of 5mL/min, at temperatures from 20 to 100°C, and outlet pressures from 80 to 300bar. The density drop was calculated based on the temperature and pressure at the column inlet and outlet. The columns were suspended in a circulating air bath, either bare or covered with foam insulation. The experimental measurements were compared to theoretical results obtained by numerical simulation. For the convective air condition at outlet pressures above 100bar the average difference between the experimental and calculated temperature drops and pressure drops were 0.1°C and 0.7% for the bare 3-μm column, respectively, and were 0.6°C and 4.1% for the insulated column. The observed temperature drops for the insulated columns are consistent with those predicted by the Joule-Thomson coefficients for isenthalpic expansion. The dependence of the temperature and the pressure drops on the Joule-Thomson coefficient and kinematic viscosity are described for carbon dioxide mobile phases containing up to 20% methanol. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

NASA Astrophysics Data System (ADS)

Gladden, H. J.; Liebert, C. H.

1980-02-01

The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

NASA Technical Reports Server (NTRS)

Gladden, H. J.; Liebert, C. H.

1980-01-01

The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

PTV analysis of the entrained air into the diesel spray at high-pressure injection

NASA Astrophysics Data System (ADS)

Toda, Naoki; Yamashita, Hayato; Mashida, Makoto

2014-08-01

In order to clarify the effect of high-pressure injection on soot reduction in terms of the air entrainment into spray, the air flow surrounding the spray and set-off length indicating the distance from the nozzle tip to the flame region in diffusion diesel combustion were investigated using 300MPa injection of a multi-hole injector. The measurement of the air entrainment flow was carried out at non-evaporating condition using consecutive PTV (particle tracking velocimetry) method with a high-speed camera and a high-frequency pulse YAG laser. The set-off length was measured at highpressure and high-temperature using the combustion bomb of constant volume and optical system of shadow graph method. And the amount of air entrainment into spray until reaching set-off length in diffusion combustion was studied as a factor of soot formation.

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2010 CFR

2010-07-01

... measurement. 91.309 Section 91.309 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 100 cm of the air-intake of the engine. The measurement location must be either in...

Risk for intracranial pressure increase related to enclosed air in post-craniotomy patients during air ambulance transport: a retrospective cohort study with simulation.

PubMed

Brändström, Helge; Sundelin, Anna; Hoseason, Daniela; Sundström, Nina; Birgander, Richard; Johansson, Göran; Winsö, Ola; Koskinen, Lars-Owe; Haney, Michael

2017-05-12

Post-craniotomy intracranial air can be present in patients scheduled for air ambulance transport to their home hospital. We aimed to assess risk for in-flight intracranial pressure (ICP) increases related to observed intracranial air volumes, hypothetical sea level pre-transport ICP, and different potential flight levels and cabin pressures. A cohort of consecutive subdural hematoma evacuation patients from one University Medical Centre was assessed with post-operative intracranial air volume measurements by computed tomography. Intracranial pressure changes related to estimated intracranial air volume effects of changing atmospheric pressure (simulating flight and cabin pressure changes up to 8000 ft) were simulated using an established model for intracranial pressure and volume relations. Approximately one third of the cohort had post-operative intracranial air. Of these, approximately one third had intracranial air volumes less than 11 ml. The simulation estimated that the expected changes in intracranial pressure during 'flight' would not result in intracranial hypertension. For intracranial air volumes above 11 ml, the simulation suggested that it was possible that intracranial hypertension could develop 'inflight' related to cabin pressure drop. Depending on the pre-flight intracranial pressure and air volume, this could occur quite early during the assent phase in the flight profile. DISCUSSION: These findings support the idea that there should be radiographic verification of the presence or absence of intracranial air after craniotomy for patients planned for long distance air transport. Very small amounts of air are clinically inconsequential. Otherwise, air transport with maintained ground-level cabin pressure should be a priority for these patients.

Define and Quantify the Physics of Air Flow, Pressure Drop and Aerosol Collection in Nuclear Grade HEPA Filters

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

Moore, Murray E.

Objective: Develop a set of peer-review and verified analytical methods to adjust HEPA filter performance to different flow rates, temperatures and altitudes. Experimental testing will measure HEPA filter flow rate, pressure drop and efficiency to verify the analytical approach. Nuclear facilities utilize HEPA (High Efficiency Particulate Air) filters to purify air flow for workspace ventilation. However, the ASME AG-1 technical standard (Code on Nuclear Air and Gas Treatment) does not adequately describe air flow measurement units for HEPA filter systems. Specifically, the AG-1 standard does not differentiate between volumetric air flow in ACFM (actual cubic feet per minute)compared to massmore » flow measured in SCFM (standard cubic feet per minute). More importantly, the AG-1 standard has an overall deficiency for using HEPA filter devices at different air flow rates, temperatures, and altitudes. Technical Approach: The collection efficiency and pressure drops of 18 different HEPA filters will be measured over a range of flow rates, temperatures and altitudes. The experimental results will be compared to analytical scoping calculations. Three manufacturers have allocated six HEPA filters each for this effort. The 18 filters will be tested at two different flow rates, two different temperatures and two different altitudes. The 36 total tests will be conducted at two different facilities: the ATI Test facilities (Baltimore MD) and the Los Alamos National Laboratory (Los Alamos NM). The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally designed to evaluate small air samplers. In 2010, modifications were started to convert the wind tunnel for HEPA filter testing. (Extensive changes were necessary for the required aerosol generators, HEPA test fixtures, temperature control devices and measurement capabilities.) To this date, none of these modification activities have been funded through a specific DOE or NNSA program

Preliminary tests of an advanced high-temperature combustion system

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

1983-01-01

A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

The impact of draught related to air velocity, air temperature and workload.

PubMed

Griefahn, B; Künemund, C; Gehring, U

2001-08-01

This experimental study was designed to test the hypotheses that the effects of draught increase with higher air velocity, with lower air temperature, and with lower workload. Thirty healthy young males were exposed to horizontal draught during 55 min while they operated an arm ergometer in a standing posture. Air velocity, air temperature, and workload were varied in 3 steps each, between 11 and 23 degrees C, 0.1 and 0.3 m/s, and 104 to 156 W/m2, respectively. The 27 combinations were distributed over subjects in a fractional factorial 3(3)-design. The participants were clothed for thermal neutrality. Workload was measured at the end of the sessions by respirometry. Draught-induced annoyance was determined every 5 min, separately for 10 body sites. Corresponding skin temperature was also recorded. The hypotheses were verified for the influence of air velocity and air temperature. Regarding workload, local heat production is probably decisive, meaning that draft-induced local annoyance is inversely related to workload in active but independent from workload in non-active body areas. To improve the situation for the workers concerned it is suggested to apply protective gloves that cover an as great area of the forearms as possible and to limit airflows to mean velocities of less than 0.2 m/s (with turbulence intensities of 50%).

Comparison of MODIS-derived land surface temperature with air temperature measurements

NASA Astrophysics Data System (ADS)

Georgiou, Andreas; Akçit, Nuhcan

2017-09-01

Air surface temperature is an important parameter for a wide range of applications such as agriculture, hydrology and climate change studies. Air temperature data is usually obtained from measurements made in meteorological stations, providing only limited information about spatial patterns over wide areas. The use of remote sensing data can help overcome this problem, particularly in areas with low station density, having the potential to improve the estimation of air surface temperature at both regional and global scales. Land Surface (skin) Temperatures (LST) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra and Aqua satellite platforms provide spatial estimates of near-surface temperature values. In this study, LST values from MODIS are compared to groundbased near surface air (Tair) measurements obtained from 14 observational stations during 2011 to 2015, covering coastal, mountainous and urban areas over Cyprus. Combining Terra and Aqua LST-8 Day and Night acquisitions into a mean monthly value, provide a large number of LST observations and a better overall agreement with Tair. Comparison between mean monthly LSTs and mean monthly Tair for all sites and all seasons pooled together yields a very high correlation and biases. In addition, the presented high standard deviation can be explained by the influence of surface heterogeneity within MODIS 1km2 grid cells, the presence of undetected clouds and the inherent difference between LST and Tair. However, MODIS LST data proved to be a reliable proxy for surface temperature and mostly for studies requiring temperature reconstruction in areas with lack of observational stations.

Preliminary Investigation on the Behavior of Pore Air Pressure During Rainfall Infiltration

NASA Astrophysics Data System (ADS)

Ashraf Mohamad Ismail, Mohd; Min, Ng Soon; Hasliza Hamzah, Nur; Hazreek Zainal Abidin, Mohd; Madun, Aziman; Tajudin, Saiful Azhar Ahmad

2018-04-01

This paper focused on the preliminary investigation of pore air pressure behaviour during rainfall infiltration in order to substantiate the mechanism of rainfall induced slope failure. The actual behaviour or pore air pressure during infiltration is yet to be clearly understood as it is regularly assumed as atmospheric. Numerical modelling of one dimensional (1D) soil column was utilized in this study to provide a preliminary insight of this highlighted uncertainty. Parametric study was performed by using rainfall intensities of 1.85 x 10-3m/s and 1.16 x 10-4m/s applied on glass beads to simulate intense and modest rainfall conditions. Analysis results show that the high rainfall intensity causes more development of pore air pressure compared to low rainfall intensity. This is because at high rainfall intensity, the rainwater cannot replace the pore air smoothly thus confining the pore air. Therefore, the effect of pore air pressure has to be taken into consideration particularly during heavy rainfall.

Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

PubMed

Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

2015-07-03

The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

High Temperature Heat Exchanger Design and Fabrication for Systems with Large Pressure Differentials

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

Chordia, Lalit; Portnoff, Marc A.; Green, Ed

The project’s main purpose was to design, build and test a compact heat exchanger for supercritical carbon dioxide (sCO 2) power cycle recuperators. The compact recuperator is required to operate at high temperature and high pressure differentials, 169 bar (~2,500 psi), between streams of sCO 2. Additional project tasks included building a hot air-to-sCO 2 Heater heat exchanger (HX) and design, build and operate a test loop to characterize the recuperator and heater heat exchangers. A novel counter-current microtube recuperator was built to meet the high temperature high differential pressure criteria and tested. The compact HX design also incorporated amore » number of features that optimize material use, improved reliability and reduced cost. The air-to-sCO 2 Heater HX utilized a cross flow, counter-current, micro-tubular design. This compact HX design was incorporated into the test loop and exceeded design expectations. The test loop design to characterize the prototype Brayton power cycle HXs was assembled, commissioned and operated during the program. Both the prototype recuperator and Heater HXs were characterized. Measured results for the recuperator confirmed the predictions of the heat transfer models developed during the project. Heater HX data analysis is ongoing.« less

Explosion bomb measurements of ethanol-air laminar gaseous flame characteristics at pressures up to 1.4 MPa

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

Bradley, D.; Lawes, M.; Mansour, M.S.

2009-07-15

The principal burning characteristics of a laminar flame comprise the fuel vapour pressure, the laminar burning velocity, ignition delay times, Markstein numbers for strain rate and curvature, the stretch rates for the onset of flame instabilities and of flame extinction for different mixtures. With the exception of ignition delay times, measurements of these are reported and discussed for ethanol-air mixtures. The measurements were in a spherical explosion bomb, with central ignition, in the regime of a developed stable, flame between that of an under or over-driven ignition and that of an unstable flame. Pressures ranged from 0.1 to 1.4 MPa,more » temperatures from 300 to 393 K, and equivalence ratios were between 0.7 and 1.5. It was important to ensure the relatively large volume of ethanol in rich mixtures at high pressures was fully evaporated. The maximum pressure for the measurements was the highest compatible with the maximum safe working pressure of the bomb. Many of the flames soon became unstable, due to Darrieus-Landau and thermo-diffusive instabilities. This effect increased with pressure and the flame wrinkling arising from the instabilities enhanced the flame speed. Both the critical Peclet number and the, more rational, associated critical Karlovitz stretch factor were evaluated at the onset of the instability. With increasing pressure, the onset of flame instability occurred earlier. The measured values of burning velocity are expressed in terms of their variations with temperature and pressure, and these are compared with those obtained by other researchers. Some comparisons are made with the corresponding properties for iso-octane-air mixtures. (author)« less

A high-temperature wideband pressure transducer

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J.

1975-01-01

Progress in the development of a pressure transducer for measurement of the pressure fluctuations in the high temperature environment of a jet exhaust is reported. A condenser microphone carrier system was adapted to meet the specifications. A theoretical analysis is presented which describes the operation of the condenser microphone in terms of geometry, materials, and other physical properties. The analysis was used as the basis for design of a prototype high temperature microphone. The feasibility of connecting the microphone to a converter over a high temperature cable operating as a half-wavelength transmission line was also examined.

Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment

NASA Astrophysics Data System (ADS)

Liaw, P. K.; Logsdon, W. A.; Begley, J. A.

1989-10-01

The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure vessel steels and submerged arc weldments were generally conservative, compared with the approrpriate American Society of Mechanical Engineers (ASME) Section XI water environmental reference curve. The growth rate of fatigue cracks in the base materials, however, was considerably faster in the HPW environment than in a corresponding 288°C (550°F) base line air environment. The growth rate of fatigue cracks in the two submerged are weldments was also accelerated in the HPW environment but to a significantly lesser degree than that demonstrated by the corresponding base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials, as compared with the weldments, was attributed to a different sulfide composition and morphology.

The influence of intraocular pressure and air jet pressure on corneal contactless tonometry tests.

PubMed

Simonini, Irene; Pandolfi, Anna

2016-05-01

The air puff is a dynamic contactless tonometer test used in ophthalmology clinical practice to assess the biomechanical properties of the human cornea and the intraocular pressure due to the filling fluids of the eye. The test is controversial, since the dynamic response of the cornea is governed by the interaction of several factors which cannot be discerned within a single measurement. In this study we describe a numerical model of the air puff tests, and perform a parametric analysis on the major action parameters (jet pressure and intraocular pressure) to assess their relevance on the mechanical response of a patient-specific cornea. The particular cornea considered here has been treated with laser reprofiling to correct myopia, and the parametric study has been conducted on both the preoperative and postoperative geometries. The material properties of the cornea have been obtained by means of an identification procedure that compares the static biomechanical response of preoperative and postoperative corneas under the physiological IOP. The parametric study on the intraocular pressure suggests that the displacement of the cornea׳s apex can be a reliable indicator for tonometry, and the one on the air jet pressure predicts the outcomes of two or more distinct measurements on the same cornea, which can be used in inverse procedures to estimate the material properties of the tissue. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco.

PubMed

Makan, Abdelhadi; Assobhei, Omar; Mountadar, Mohammed

2013-01-03

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco

PubMed Central

2013-01-01

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts. For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times. This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications. PMID:23369502

Can air temperatures be used to project influences of climate change on stream temperatures?

NASA Astrophysics Data System (ADS)

Arismendi, I.; Safeeq, M.; Dunham, J.; Johnson, S. L.

2013-12-01

The lack of available in situ stream temperature records at broad spatiotemporal scales have been recognized as a major limiting factor in the understanding of thermal behavior of stream and river systems. This has motivated the promotion of a wide variety of models that use surrogates for stream temperatures including a regression approach that uses air temperature as the predictor variable. We investigate the long-term performance of widely used linear and non-linear regression models between air and stream temperatures to project the latter in future climate scenarios. Specifically, we examine the temporal variability of the parameters that define each of these models in long-term stream and air temperature datasets representing relatively natural and highly human-influenced streams. We selected 25 sites with long-term records that monitored year-round daily measurements of stream temperature (daily mean) in the western United States (California, Oregon, Idaho, Washington, and Alaska). Surface air temperature data from each site was not available. Therefore, we calculated daily mean surface air temperature for each site in contiguous US from a 1/16-degree resolution gridded surface temperature data. Our findings highlight several limitations that are endemic to linear or nonlinear regressions that have been applied in many recent attempts to project future stream temperatures based on air temperature. Our results also show that applications over longer time periods, as well as extrapolation of model predictions to project future stream temperatures are unlikely to be reliable. Although we did not analyze a broad range of stream types at a continental or global extent, our analysis of stream temperatures within the set of streams considered herein was more than sufficient to illustrate a number of specific limitations associated with statistical projections of stream temperature based on air temperature. Radar plots of Nash-Sutcliffe efficiency (NSE) values for

Method and apparatus for monitoring oxygen partial pressure in air masks

NASA Technical Reports Server (NTRS)

Kelly, Mark E. (Inventor); Pettit, Donald R. (Inventor)

2006-01-01

Method and apparatus are disclosed for monitoring an oxygen partial pressure in an air mask and providing a tactile warning to the user. The oxygen partial pressure in the air mask is detected using an electrochemical sensor, the output signal from which is provided to a comparator. The comparator compares the output signal with a preset reference value or range of values representing acceptable oxygen partial pressures. If the output signal is different than the reference value or outside the range of values, the air mask is vibrated by a vibrating motor to alert the user to a potentially hypoxic condition.

Prosthetics socket that incorporates an air splint system focusing on dynamic interface pressure.

PubMed

Razak, Nasrul Anuar Abd; Osman, Noor Azuan Abu; Gholizadeh, Hossein; Ali, Sadeeq

2014-08-01

The interface pressure between the residual limb and prosthetic socket has a significant effect on an amputee's satisfaction and comfort. This paper presents the design and performance of a new prosthetic socket that uses an air splint system. The air splint prosthetic socket system was implemented by combining the air splint with a pressure sensor that the transhumeral user controls through the use of a microcontroller. The modular construction of the system developed allows the FSR pressure sensors that are placed inside the air splint socket to determine the required size and fitting for the socket used. Fifteen transhumeral amputees participated in the study. The subject's dynamic pressure on the socket that's applied while wearing the air splint systems was recorded using F-socket transducers and microcontroller analysis. The values collected by the F-socket sensor for the air splint prosthetic socket system were determined accordingly by comparing the dynamic pressure applied using statically socket. The pressure volume of the air splint fluctuated and was recorded at an average of 38 kPa (2.5) to 41 kPa (1.3) over three hours. The air splint socket might reduce the pressure within the interface of residual limb. This is particularly important during the daily life activities and may reduce the pain and discomfort at the residual limb in comparison to the static socket. The potential development of an auto-adjusted socket that uses an air splint system as the prosthetic socket will be of interest to researchers involved in rehabilitation engineering, prosthetics and orthotics.

Experimental Heat Transfer and Bulk Air Temperature Measurements for a Multipass Internal Cooling Model with Ribs and Bleed

NASA Technical Reports Server (NTRS)

Thurman, Douglas; Poinsatte, Philip

2001-01-01

An experimental study was made to obtain heat transfer and air temperature data for a simple three-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady-state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discrete locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model.

Experimental Heat Transfer and Bulk Air Temperature Measurements for a Multipass Internal Cooling Model with Ribs and Bleed

NASA Technical Reports Server (NTRS)

Thurman, Douglas; Poinsatte, Philip

2000-01-01

An experimental study was made to obtain heat transfer and air temperature data for a simple 3-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discreet locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model.

Soil and air temperatures for different habitats in Mount Rainier National Park.

Treesearch

Sarah E. Greene; Mark Klopsch

1985-01-01

This paper reports air and soil temperature data from 10 sites in Mount Rainier National Park in Washington State for 2- to 5-year periods. Data provided are monthly summaries for day and night mean air temperatures, mean minimum and maximum air temperatures, absolute minimum and maximum air temperatures, range of air temperatures, mean soil temperature, and absolute...

Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

NASA Technical Reports Server (NTRS)

Dugger, Gordon L

1952-01-01

Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

Crowdsourcing urban air temperatures through smartphone battery temperatures in São Paulo, Brazil

NASA Astrophysics Data System (ADS)

Droste, Arjan; Pape, Jan-Jaap; Overeem, Aart; Leijnse, Hidde; Steeneveld, Gert-Jan; Van Delden, Aarnout; Uijlenhoet, Remko

2017-04-01

Crowdsourcing as a method to obtain and apply vast datasets is rapidly becoming prominent in meteorology, especially for urban areas where traditional measurements are scarce. Earlier studies showed that smartphone battery temperature readings allow for estimating the daily and city-wide air temperature via a straightforward heat transfer model. This study advances these model estimations by studying spatially and temporally smaller scales. The accuracy of temperature retrievals as a function of the number of battery readings is also studied. An extensive dataset of over 10 million battery temperature readings is available for São Paulo (Brazil), for estimating hourly and daily air temperatures. The air temperature estimates are validated with air temperature measurements from a WMO station, an Urban Fluxnet site, and crowdsourced data from 7 hobby meteorologists' private weather stations. On a daily basis temperature estimates are good, and we show they improve by optimizing model parameters for neighbourhood scales as categorized in Local Climate Zones. Temperature differences between Local Climate Zones can be distinguished from smartphone battery temperatures. When validating the model for hourly temperature estimates, initial results are poor, but are vastly improved by using a diurnally varying parameter function in the heat transfer model rather than one fixed value for the entire day. The obtained results show the potential of large crowdsourced datasets in meteorological studies, and the value of smartphones as a measuring platform when routine observations are lacking.

How strong is the impact of the Indo-ocean dipole on the surface air temperature/sea level pressure anomalies in the Mediterranean region?

NASA Astrophysics Data System (ADS)

Polonsky, Alexander B.; Basharin, Dmitry V.

2017-04-01

The aim of this paper is to study the interannual climate variability over the Mediterranean region related to the Indo-ocean dipole (IOD) using the data of re-analyses, archival data and specialized numerical experiments. It is shown that the IOD does not impact essentially the anomalies of surface air temperature (SAT) and sea level pressure (SLP) in the Mediterranean region. On average, the IOD-induced share of the SAT/SLP variance in the total variance of these fields in the Mediterranean region is smaller than 10% even in summer when it is at a maximum. However, the statistically significant IOD-induced SAT/SLP anomalies in the Mediterranean region are detectable. For definite IOD events the associated Mediterranean SAT anomalies can reach about 1 °C.

A Proposed Dynamic Pressure and Temperature Primary Standard

PubMed Central

Rosasco, Gregory J.; Bean, Vern E.; Hurst, Wilbur S.

1990-01-01

Diatomic gas molecules have a fundamental vibrational motion whose frequency is affected by pressure in a simple way. In addition, these molecules have well defined rotational energy levels whose populations provide a reliable measure of the thermodynamic temperature. Since information concerning the frequency of vibration and the relative populations can be determined by laser spectroscopy, the gas molecules themselves can serve as sensors of pressure and temperature. Through measurements under static conditions, the pressure and temperature dependence of the spectra of selected molecules is now understood. As the time required for the spectroscopic measurement can be reduced to nanoseconds, the diatomic gas molecule is an excellent candidate for a dynamic pressure/temperature primary standard. The temporal response in this case will be limited by the equilibration time for the molecules to respond to changes in local thermodynamic variables. Preliminary feasibility studies suggest that by using coherent anti-Stokes Raman spectroscopy we will be able to measure dynamic pressure up to 108 Pa and dynamic temperature up to 1500 K with an uncertainty of 5%. PMID:28179756

40 CFR 90.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature measurement. 90.309 Section 90.309 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...

Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

Weather and climate needs for Lidar observations from space and concepts for their realization. [wind, temperature, moisture, and pressure data needs

NASA Technical Reports Server (NTRS)

Atlas, D.; Korb, C. L.

1980-01-01

The spectrum of weather and climate needs for Lidar observations from space is discussed with emphasis on the requirements for wind, temperature, moisture, and pressure data. It is shown that winds are required to realistically depict all atmospheric scales in the tropics and the smaller scales at higher latitudes, where both temperature and wind profiles are necessary. The need for means to estimate air-sea exchanges of sensible and latent heat also is noted. A concept for achieving this through a combination of Lidar cloud top heights and IR cloud top temperatures of cloud streets formed during cold air outbreaks over the warmer ocean is outlined. Recent theoretical feasibility studies concerning the profiling of temperatures, pressure, and humidity by differential absorption Lidar (DIAL) from space and expected accuracies are reviewed. An alternative approach to Doppler Lidar wind measurements also is presented. The concept involves the measurement of the displacement of the aerosol backscatter pattern, at constant heights, between two successive scans of the same area, one ahead of the spacecraft and the other behind it a few minutes later. Finally, an integrated space Lidar system capable of measuring temperature, pressure, humidity, and winds which combines the DIAL methods with the aerosol pattern displacement concept is described.

Low temperature air with high IAQ for dry climates

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

Scofield, C.M.; Des Champs, N.H.

1995-01-01

This article describes how low temperature supply air and air-to-air heat exchangers can furnish 100% outdoor air with reduced peak energy demands. The use of low temperature supply air systems in arid climates greatly simplifies the air-conditioning design. Risks associated with moisture migration and sweating of duct and terminal equipment are reduced. Insulation and vapor barrier design requirements are not nearly as critical as they are in the humid, ambient conditions that exist in the eastern United States. The introduction of outdoor air to meet ASHRAE Standard 62-1989 becomes far less taxing on the mechanical cooling equipment because of themore » lower enthalpy levels of the dry western climate. Energy costs to assure indoor air quality (IAQ) are lower than for more tropical climates. In arid regions, maintaining acceptable indoor relative humidity (RH) levels becomes a major IAQ concern. For the western United States, coupling an air-to-air heat exchanger to direct (adiabatic) evaporative coolers can greatly reduce low temperature supply air refrigeration energy requirements and winter humidification costs while ensuring proper ventilation.« less

Influence of snow temperature on avalanche impact pressure

NASA Astrophysics Data System (ADS)

Sovilla, Betty; Koehler, Anselm; Steinkogler, Walter; Fischer, Jan-Thomas

2015-04-01

The properties of the snow entrained by an avalanche during its motion (density, temperature) significantly affect flow dynamics and can determine whether the flowing material forms granules or maintains its original fine-grained structure. In general, a cold and light snow cover typically fluidizes, while warmer and more cohesive snow may form a granular denser layer in a flowing avalanche. This structural difference has a fundamental influence not only in the mobility of the flow but also on the impact pressure of avalanches. Using measurements of impact pressure, velocity, density and snow temperature performed at the Swiss Vallée de la Sionne full-scale test site, we show that, impact pressure fundamentally changes with snow temperature. A transition threshold of about -2°C is determined, the same temperature at which snow granulation starts. On the one hand warm avalanches, characterized by temperatures larger than -2°C, move as a plug and exert impact pressures linearly proportional to the avalanche depth. For Froude numbers larger than 1, an additional square-velocity dependent contribution cannot be neglected. On the other hand cold avalanches, characterized by a temperature smaller than -2°C, move as dense sheared flows, or completely dilute powder clouds and exert impact pressures, which are mainly proportional to the square of the flow velocity. For these avalanches the impact pressures strongly depend on density variations within the flow. We suggest that the proposed temperature threshold can be used as a criterion to define the transition between the impact pressures exerted by warm and cold avalanches, thus offering a new way to elude the notorious difficulties in defining the differences between wet and dry flow, respectively.

Heat transfer and pressure drop for air flow through enhanced passages. Final report

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

Obot, N.T.; Esen, E.B.

1992-06-01

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effectmore » depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.« less

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

Prosthetics socket that incorporates an air splint system focusing on dynamic interface pressure

PubMed Central

2014-01-01

Background The interface pressure between the residual limb and prosthetic socket has a significant effect on an amputee’s satisfaction and comfort. This paper presents the design and performance of a new prosthetic socket that uses an air splint system. Methods The air splint prosthetic socket system was implemented by combining the air splint with a pressure sensor that the transhumeral user controls through the use of a microcontroller. The modular construction of the system developed allows the FSR pressure sensors that are placed inside the air splint socket to determine the required size and fitting for the socket used. Fifteen transhumeral amputees participated in the study. Results The subject’s dynamic pressure on the socket that’s applied while wearing the air splint systems was recorded using F-socket transducers and microcontroller analysis. The values collected by the F-socket sensor for the air splint prosthetic socket system were determined accordingly by comparing the dynamic pressure applied using statically socket. The pressure volume of the air splint fluctuated and was recorded at an average of 38 kPa (2.5) to 41 kPa (1.3) over three hours. Conclusion The air splint socket might reduce the pressure within the interface of residual limb. This is particularly important during the daily life activities and may reduce the pain and discomfort at the residual limb in comparison to the static socket. The potential development of an auto-adjusted socket that uses an air splint system as the prosthetic socket will be of interest to researchers involved in rehabilitation engineering, prosthetics and orthotics. PMID:25085005

Experimental investigation on pressurization performance of cryogenic tank during high-temperature helium pressurization process

NASA Astrophysics Data System (ADS)

Lei, Wang; Yanzhong, Li; Yonghua, Jin; Yuan, Ma

2015-03-01

Sufficient knowledge of thermal performance and pressurization behaviors in cryogenic tanks during rocket launching period is of importance to the design and optimization of a pressurization system. In this paper, ground experiments with liquid oxygen (LO2) as the cryogenic propellant, high-temperature helium exceeding 600 K as the pressurant gas, and radial diffuser and anti-cone diffuser respectively at the tank inlet were performed. The pressurant gas requirements, axial and radial temperature distributions, and energy distributions inside the propellant tank were obtained and analyzed to evaluate the comprehensive performance of the pressurization system. It was found that the pressurization system with high-temperature helium as the pressurant gas could work well that the tank pressure was controlled within a specified range and a stable discharging liquid rate was achieved. For the radial diffuser case, the injected gas had a direct impact on the tank inner wall. The severe gas-wall heat transfer resulted in about 59% of the total input energy absorbed by the tank wall. For the pressurization case with anti-cone diffuser, the direct impact of high-temperature gas flowing toward the liquid surface resulted in a greater deal of energy transferred to the liquid propellant, and the percentage even reached up to 38%. Moreover, both of the two cases showed that the proportion of energy left in ullage to the total input energy was quite small, and the percentage was only about 22-24%. This may indicate that a more efficient diffuser should be developed to improve the pressurization effect. Generally, the present experimental results are beneficial to the design and optimization of the pressurization system with high-temperature gas supplying the pressurization effect.

40 CFR 90.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C. ...

40 CFR 90.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C. ...

40 CFR 90.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C. ...

40 CFR 90.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C. ...

Emission measurements for a lean premixed propane/air system at pressures up to 30 atmospheres

NASA Technical Reports Server (NTRS)

Roffe, G.; Venkataramani, K. S.

1978-01-01

The emissions of a lean premixed system of propane/air were measured in a flametube apparatus. Tests were conducted at inlet temperatures of 600K and 800K and pressures of 10 atm and 30 atm over a range of equivalence ratios. The data obtained were combined with previous data taken in the same apparatus to correlate nitrogen oxide emissions with operating conditions. Sampling probe design was found to have a pronounced effect on measured CO levels but did not influence measurements. The most effective probe tested was one which combined thermal and pressure quenching of the gas sample.

Optical Pressure-Temperature Sensor for a Combustion Chamber

NASA Technical Reports Server (NTRS)

Wiley, John; Korman, Valentin; Gregory, Don

2008-01-01

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

49 CFR 393.51 - Warning signals, air pressure and vacuum gauges.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Warning signals, air pressure and vacuum gauges... REGULATIONS PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION Brakes § 393.51 Warning signals, air pressure... paragraphs (b), (c), (d) or (e) of this section. (b) Hydraulic brakes. Vehicles manufactured on or after...

49 CFR 393.51 - Warning signals, air pressure and vacuum gauges.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Warning signals, air pressure and vacuum gauges... REGULATIONS PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION Brakes § 393.51 Warning signals, air pressure... paragraphs (b), (c), (d) or (e) of this section. (b) Hydraulic brakes. Vehicles manufactured on or after...

High pressure and high temperature apparatus

DOEpatents

Voronov, Oleg A.

2005-09-13

A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

The relation of cool flames and auto-ignition phenomena to process safety at elevated pressure and temperature.

PubMed

Pekalski, A A; Zevenbergen, J F; Pasman, H J; Lemkowitz, S M; Dahoe, A E; Scarlett, B

2002-07-01

The cool-flame phenomenon can occur in fuel-oxygen (air) mixtures within the flammable range and outside the flammable range, at fuel-rich compositions, at temperatures below the auto-ignition temperature (AIT). It is caused by chemical reactions occurring spontaneously at relatively low temperatures and is favoured by elevated pressure. The hazards that cool flames generate are described. These vary from spoiling a product specification through contamination and explosive decomposition of condensed peroxides to the appearance of unexpected normal (hot) flame (two-stage ignition).

Simple Experiments for Teaching Air Pressure

ERIC Educational Resources Information Center

Shamsipour, Gholamreza

2006-01-01

Everyone who teaches physics knows very well that sometimes a simple device or experiment can help to make a concept clear. In this paper, inspired by "The Jumping Pencil" by Martin Gardner, I will discuss a simple demonstration device that can be used to start the study of air pressure.

The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger

NASA Astrophysics Data System (ADS)

Borcuch, Marcin; Musiał, Michał; Sztekler, Karol; Kalawa, Wojciech; Gumuła, Stanisław; Stefański, Sebastian

2018-06-01

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.

Possible Economies in Air-Conditioning by Accepting Temperature Swings.

ERIC Educational Resources Information Center

Loudon, A. G.; Petherbridge, P.

Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

49 CFR 393.51 - Warning signals, air pressure and vacuum gauges.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Warning signals, air pressure and vacuum gauges... REGULATIONS PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION Brakes § 393.51 Warning signals, air pressure... paragraph (f), must be equipped with a signal that provides a warning to the driver when a failure occurs in...

49 CFR 393.51 - Warning signals, air pressure and vacuum gauges.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 5 2012-10-01 2012-10-01 false Warning signals, air pressure and vacuum gauges... REGULATIONS PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION Brakes § 393.51 Warning signals, air pressure... paragraph (f), must be equipped with a signal that provides a warning to the driver when a failure occurs in...

Simulation and Experiment Research on Fatigue Life of High Pressure Air Pipeline Joint

NASA Astrophysics Data System (ADS)

Shang, Jin; Xie, Jianghui; Yu, Jian; Zhang, Deman

2017-12-01

High pressure air pipeline joint is important part of high pressure air system, whose reliability is related to the safety and stability of the system. This thesis developed a new type-high pressure air pipeline joint, carried out dynamics research on CB316-1995 and new type-high pressure air pipeline joint with finite element method, deeply analysed the join forms of different design schemes and effect of materials on stress, tightening torque and fatigue life of joint. Research team set up vibration/pulse test bench, carried out joint fatigue life contrast test. The result shows: the maximum stress of the joint is inverted in the inner side of the outer sleeve nut, which is consistent with the failure mode of the crack on the outer sleeve nut in practice. Simulation and experiment of fatigue life and tightening torque of new type-high pressure air pipeline joint are better than CB316-1995 joint.

Air breathing in the Arctic: influence of temperature, hypoxia, activity and restricted air access on respiratory physiology of the Alaska blackfish Dallia pectoralis

PubMed Central

Lefevre, Sjannie; Damsgaard, Christian; Pascale, Desirae R.; Nilsson, Göran E.; Stecyk, Jonathan A. W.

2014-01-01

The Alaska blackfish (Dallia pectoralis) is an air-breathing fish native to Alaska and the Bering Sea islands, where it inhabits lakes that are ice-covered in the winter, but enters warm and hypoxic waters in the summer to forage and reproduce. To understand the respiratory physiology of this species under these conditions and the selective pressures that maintain the ability to breathe air, we acclimated fish to 5°C and 15°C and used respirometry to measure: standard oxygen uptake () in normoxia (19.8 kPa PO2) and hypoxia (2.5 kPa), with and without access to air; partitioning of standard in normoxia and hypoxia; maximum and partitioning after exercise; and critical oxygen tension (Pcrit). Additionally, the effects of temperature acclimation on haematocrit, haemoglobin oxygen affinity and gill morphology were assessed. Standard was higher, but air breathing was not increased, at 15°C or after exercise at both temperatures. Fish acclimated to 5°C or 15°C increased air breathing to compensate and fully maintain standard in hypoxia. Fish were able to maintain through aquatic respiration when air was denied in normoxia, but when air was denied in hypoxia, standard was reduced by ∼30–50%. Pcrit was relatively high (5 kPa) and there were no differences in Pcrit, gill morphology, haematocrit or haemoglobin oxygen affinity at the two temperatures. Therefore, Alaska blackfish depends on air breathing in hypoxia and additional mechanisms must thus be utilised to survive hypoxic submergence during the winter, such as hypoxia-induced enhancement in the capacities for carrying and binding blood oxygen, behavioural avoidance of hypoxia and suppression of metabolic rate. PMID:25394628

Decomposition of silicon carbide at high pressures and temperatures

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

Daviau, Kierstin; Lee, Kanani K. M.

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

Measurement Corner: Volume, Temperature and Pressure

ERIC Educational Resources Information Center

Teates, Thomas G.

1977-01-01

Boyle's Law and basic relationships between volume and pressure of a gas at constant temperature are presented. Suggests two laboratory activities for demonstrating the effect of temperature on the volume of a gas or liquid. (CS)

HIGH-TEMPERATURE AND HIGH-PRESSURE PARTICULATE CONTROL REQUIREMENTS

EPA Science Inventory

The report reviews and evaluates high-temperature and high-pressure particulate cleanup requirements of existing and proposed energy processes. The study's aims are to define specific high-temperature and high-pressure particle removal problems, to indicate potential solutions, a...

Auto-ignitions of a methane/air mixture at high and intermediate temperatures

NASA Astrophysics Data System (ADS)

Leschevich, V. V.; Martynenko, V. V.; Penyazkov, O. G.; Sevrouk, K. L.; Shabunya, S. I.

2016-09-01

A rapid compression machine (RCM) and a shock tube (ST) have been employed to study ignition delay times of homogeneous methane/air mixtures at intermediate-to-high temperatures. Both facilities allow measurements to be made at temperatures of 900-2000 K, at pressures of 0.38-2.23 MPa, and at equivalence ratios of 0.5, 1.0, and 2.0. In ST experiments, nitrogen served as a diluent gas, whereas in RCM runs the diluent gas composition ranged from pure nitrogen to pure argon. Recording pressure, UV, and visible emissions identified the evolution of chemical reactions. Correlations of ignition delay time were generated from the data for each facility. At temperatures below 1300 K, a significant reduction of average activation energy from 53 to 15.3 kcal/mol was obtained. Moreover, the RCM data showed significant scatter that dramatically increased with decreasing temperature. An explanation for the abnormal scatter in the data was proposed based on the high-speed visualization of auto-ignition phenomena and experiments performed with oxygen-free and fuel-free mixtures. It is proposed that the main reason for such a significant reduction of average activation energy is attributable to the premature ignition of ultrafine particles in the reactive mixture.

Pressure-Temperature Simulation at Brady Hot Springs

DOE Data Explorer

Feigl, Kurt (ORCID:0000000220596708)

2017-07-11

These files contain the output of a model calculation to simulate the pressure and temperature of fluid at Brady Hot Springs, Nevada, USA. The calculation couples the hydrologic flow (Darcy's Law) with simple thermodynamics. The epoch of validity is 24 March 2015. Coordinates are UTM Easting, Northing, and Elevation in meters. Temperature is specified in degrees Celsius. Pressure is specified in Pascal.

Compressed-air work is entering the field of high pressures.

PubMed

Le Péchon, J Cl; Gourdon, G

2010-01-01

Since 1850, compressed-air work has been used to prevent shafts or tunnels under construction from flooding. Until the 1980s, workers were digging in compressed-air environments. Since the introduction of tunnel boring machines (TBMs), very little digging under pressure is needed. However, the wearing out of cutter-head tools requires inspection and repair. Compressed-air workers enter the pressurized working chamber only occasionally to perform such repairs. Pressures between 3.5 and 4.5 bar, that stand outside a reasonable range for air breathing, were reached by 2002. Offshore deep diving technology had to be adapted to TBM work. Several sites have used mixed gases: in Japan for deep shaft sinking (4.8 bar), in The Netherlands at Western Scheldt Tunnels (6.9 bar), in Russia for St. Petersburg Metro (5.8 bar) and in the United States at Seattle (5.8 bar). Several tunnel projects are in progress that may involve higher pressures: Hallandsås (Sweden) interventions in heliox saturation up to 13 bar, and Lake Mead (U.S.) interventions to about 12 bar (2010). Research on TBMs and grouting technologies tries to reduce the requirements for hyperbaric works. Adapted international rules, expertise and services for saturation work, shuttles and trained personnel matching industrial requirements are the challenges.

Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios

PubMed Central

Shen, Rui; Suuberg, Eric M.

2016-01-01

There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures. PMID:28090133

Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios.

PubMed

Shen, Rui; Suuberg, Eric M

2016-02-01

There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures.

Sea surface temperature measurements with AIRS

NASA Technical Reports Server (NTRS)

Aumann, H.

2003-01-01

The comparison of global sea surface skin temperature derived from cloud-free AIRS super window channel at 2616 cm-1 (sst2616) with the Real-Time Global Sea Surface Temperature for September 2002 shows surprisingly small standard deviation of 0.44K.

Plasma-assisted combustion in lean, high-pressure, preheated air-methane mixtures

NASA Astrophysics Data System (ADS)

Sommerer, Timothy; Herbon, John; Saddoughi, Seyed; Deminsky, Maxim; Potapkin, Boris

2013-09-01

We combine a simplified physical model with a detailed plasma-chemical reaction mechanism to analyze the use of plasmas to improve flame stability in a gas turbine used for electric power generation. For this application the combustion occurs in a lean mixture of air and methane at high pressure (18.6 atm) and at ``preheat'' temperature 700 K, and the flame zone is both recirculating and turbulent. The system is modeled as a sequence of reactors: a pulsed uniform plasma (Boltzmann), an afterglow region (plug-flow), a flame region (perfectly-stirred), and a downstream region (plug-flow). The plasma-chemical reaction mechanism includes electron-impact on the feedstock species, relaxation in the afterglow to neutral molecules and radicals, and methane combustion chemistry (GRI-Mech 3.0), with extensions to properly describe low-temperature combustion 700-1000 K [M Deminsky et al., Chem Phys 32, 1 (2013)]. We find that plasma treatment of the incoming air-fuel mixture can improve the stability of lean flames, expressed as a reduction in the adiabatic flame temperature at lean blow-out, but that the plasma also generates oxides of nitrogen at the preheat temperature through the reactions e + N2 --> N + N and N + O2 --> NO + O. We find that flame stability is improved with less undesirable NOx formation when the plasma reduced-electric-field E/ N is smaller. A portion of this work was supported by the US Dept of Energy under Award Number DE-FC26-08NT05868.

Fiber optic photoelastic pressure sensor for high temperature gases

NASA Technical Reports Server (NTRS)

Wesson, Laurence N.; Redner, Alex S.; Baumbick, Robert J.

1990-01-01

A novel fiber optic pressure sensor based on the photoelastic effects has been developed for extremely high temperature gases. At temperatures varying from 25 to 650 C, the sensor experiences no change in the peak pressure of the transfer function and only a 10 percent drop in dynamic range. Refinement of the sensor has resulted in an optoelectronic interface and processor software which can calculate pressure values within 1 percent of full scale at any temperature within the full calibrated temperature range.

Computer modeling of the sensitivity of a laser water vapor sensor to variations in temperature and air speed

NASA Technical Reports Server (NTRS)

Tucker, George F.

1994-01-01

Currently, there is disagreement among existing methods of determining atmospheric water vapor concentration at dew-points below -40 C. A major source of error is wall effects which result from the necessity of bringing samples into the instruments. All of these instruments also have response times on the order of seconds. NASA Langley is developing a water vapor sensor which utilizes the absorption of the infrared radiation produced by a diode laser to estimate water vapor concentration. The laser beam is directed through an aircraft window to a retroreflector located on an engine. The reflected beam is detected by an infrared detector located near the laser. To maximize signal to noise, derivative signals are analyzed. By measuring the 2f/DC signal and correcting for ambient temperature, atmospheric pressure and air speed (which results in a Doppler shifting of the laser beam), the water vapor concentration can be retrieved. Since this is an in situ measurement there are no wall effects and measurements can be made at a rate of more than 20 per second. This allows small spatial variations of water vapor to be studied. In order to study the sensitivity of the instrument to variations in temperature and air speed, a computer program which generated the 2f, 3f, 4f, DC and 2f/DC signals of the instrument as a function of temperature, pressure and air speed was written. This model was used to determine the effect of errors in measurement of the temperature and air speed on the measured water vapor concentration. Future studies will quantify the effect of pressure measurement errors, which are expected to be very small. As a result of these studied, a retrieval algorithm has been formulated, and will be applied to data taken during the PEM-West atmospheric science field mission. Spectroscopic studies of the water vapor line used by the instrument will be used to refine this algorithm. To prepare for these studies, several lasers have been studied to determine their

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Inspection of compressed-air receivers and...-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13015 Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Inspection of compressed-air receivers and... METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13015 Inspection of compressed-air receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels...

Tables for pressure of air on coming to rest from various speeds

NASA Technical Reports Server (NTRS)

Zahm, A F; Louden, F A

1930-01-01

In Technical Report no. 247 of the National Advisory Committee for Aeronautics theoretical formulas are given from which was computed a table for the pressure of air on coming to rest from various speeds, such as those of aircraft and propeller blades. In that report, the table gave incompressible and adiabatic stop pressures of air for even-speed intervals in miles per hour and for some even-speed intervals in knots per hour. Table II of the present report extends the above-mentioned table by including the stop pressures of air for even-speed intervals in miles per hour, feet per-second, knots per hour, kilometers per hour, and meters per second. The pressure values in table II are also more exact than values given in the previous table. To furnish the aeronautical engineer with ready numerical formulas for finding the pressure of air on coming to rest, table I has been derived for the standard values specified below it. This table first presents the theoretical pressure-speed formulas and their working forms in C. G. S. Units as given in NACA Technical Report No. 247, then furnishes additional working formulas for several special units of speed. (author)

Temperature dependence of thermal pressure for NaCl

NASA Astrophysics Data System (ADS)

Singh, Chandra K.; Pande, Brijesh K.; Pandey, Anjani K.

2018-05-01

Engineering applications of the materials can be explored upto the desired limit of accuracy with the better knowledge of its mechanical and thermal properties such as ductility, brittleness and Thermal Pressure. For the resistance to fracture (K) and plastic deformation (G) the ratio K/G is treated as an indication of ductile or brittle character of solids. In the present work we have tested the condition of ductility and brittleness with the calculated values of K/G for the NaCl. It is concluded that the nature of NaCl can be predicted upto high temperature simply with the knowledge of its elastic stiffness constant only. Thermoelastic properties of materials at high temperature is directly related to thermal pressure and volume expansion of the materials. An expression for the temperature dependence of thermal pressure is formulated using basic thermodynamic identities. It is observed that thermal pressure ΔPth calculated for NaCl by using Kushwah formulation is in good agreement with the experimental values also the thermal pressure increases with the increase in temperature.

Sensitivity of Great Lakes Ice Cover to Air Temperature

NASA Astrophysics Data System (ADS)

Austin, J. A.; Titze, D.

2016-12-01

Ice cover is shown to exhibit a strong linear sensitivity to air temperature. Upwards of 70% of ice cover variability on all of the Great Lakes can be explained in terms of air temperature, alone, and nearly 90% of ice cover variability can be explained in some lakes. Ice cover sensitivity to air temperature is high, and a difference in seasonally-averaged (Dec-May) air temperature on the order of 1°C to 2°C can be the difference between a low-ice year and a moderate- to high- ice year. The total amount of seasonal ice cover is most influenced by air temperatures during the meteorological winter, contemporaneous with the time of ice formation. Air temperature conditions during the pre-winter conditioning period and during the spring melting period were found to have less of an impact on seasonal ice cover. This is likely due to the fact that there is a negative feedback mechanism when heat loss goes toward cooling the lake, but a positive feedback mechanism when heat loss goes toward ice formation. Ice cover sensitivity relationships were compared between shallow coastal regions of the Great Lakes and similarly shallow smaller, inland lakes. It was found that the sensitivity to air temperature is similar between these coastal regions and smaller lakes, but that the absolute amount of ice that forms varies significantly between small lakes and the Great Lakes, and amongst the Great Lakes themselves. The Lake Superior application of the ROMS three-dimensional hydrodynamic numerical model verifies a deterministic linear relationship between air temperature and ice cover, which is also strongest around the period of ice formation. When the Lake Superior bathymetry is experimentally adjusted by a constant vertical multiplier, average lake depth is shown to have a nonlinear relationship with seasonal ice cover, and this nonlinearity may be associated with a nonlinear increase in the lake-wide volume of the surface mixed layer.

On the importance of high-frequency air-temperature fluctuations for spectroscopic corrections of open-path carbon dioxide flux measurements

NASA Astrophysics Data System (ADS)

Bogoev, Ivan; Helbig, Manuel; Sonnentag, Oliver

2015-04-01

A growing number of studies report systematic differences in CO2 flux estimates obtained with the two main types of gas analyzers: compared to eddy-covariance systems based on closed-path (CP) gas analyzers, systems with open-path (OP) gas analyzers systematically overestimate CO2 uptake during daytime periods with high positive sensible heat fluxes, while patterns for differences in nighttime CO2 exchange are less obvious. These biases have been shown to correlate with the sign and the magnitude of the sensible heat flux and to introduce large uncertainties when calculating annual CO2 budgets. In general, CP and OP gas analyzers commonly used to measure the CO2 density in the atmosphere operate on the principle of infrared light absorption approximated by Beer-Lambert's law. Non-dispersive interference-based optical filter elements are used to select spectral bands with strong attenuation of light transmission, characteristic to the gas of interest. The intensity of the light passing through the optical sensing path depends primarily on the amount of absorber gas in the measurement volume. Besides the density of the gas, barometric pressure and air temperature are additional factors affecting the strength and the half-width of the absorption lines. These so-called spectroscopic effects are accounted for by measuring barometric pressure and air temperature in the sensing path and scaling the light-intensity measurements before applying the calibration equation. This approach works well for CP gas analyzers with an intake tube that acts as a low-pass filter on fast air-temperature fluctuations. Low-frequency response temperature sensors in the measurement cell are therefore sufficient to account for spectroscopic temperature effects. In contrast, OP gas analyzers are exposed to high-frequency air-temperature fluctuations associated with the atmospheric surface-layer turbulent heat exchange. If not corrected adequately, these fast air-temperature variations can cause

Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment

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

Liaw, P.K.; Logsdon, W.A.; Begley, J.A.

1989-10-01

The fatigue crack growth rate (FCGR) properties of SA508 Cl 2a and SA533 Gr A Cl 2 pressure vessel steels and the corresponding automatic submerged arc weldments were developed in a high-temperature pressurized water (HPW) environment at 288{degrees} C (550{degrees} F) and 7.2 MPa (1044 psi) at load ratios of 0.20 and 0.50. The properties were generally conservative compared to American Society of Mechanical Engineers Section XI water environment reference curve. The growth rate of fatigue cracks in the base materials, however, was faster in the HPW environment than in a 288{degrees} C (550{degrees} F) base line air environment. Themore » growth rate of fatigue cracks in the two submerged arc weldments was also accelerated in the HPW environment but to a lesser degree than that demonstrated by the base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials compared the weldments attributed to a different sulfide composition and morphology.« less

Variation of Azeotropic Composition and Temperature with Pressure

ERIC Educational Resources Information Center

Gibbard, H. Frank; Emptage, Michael R.

1975-01-01

Describes an undergraduate physical chemistry experiment in which an azeotropic mixture is studied using the vapor pressures of the components as functions of temperature and the azeotropic composition and temperature at one pressure. Discusses in detail the mathematical treatment of obtained thermodynamic data. (MLH)

Air- and N2-Broadening Coefficients and Pressure-Shift Coefficients in the C-12(O2-16) Laser Bands

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Smith, Mary Ann H.; Rinsland, Curtis P.

1998-01-01

In this paper we report the pressure broadening and the pressure-induced line shift coefficients for 46 individual rovibrational lines in both the (12)C(16)O2, 00(sup 0)1-(10(sup 0)0-02(sup 0)0)I, and 00(sup 0)1-(10(sup 0)0-02(sup 0)0)II, laser bands (laser band I centered at 960.959/cm and laser band II centered at 1063.735/cm) determined from spectra recorded with the McMath-Pierce Fourier transform spectrometer. The results were obtained from analysis of 10 long-path laboratory absorption spectra recorded at room temperature using a multispectrum nonlinear least-squares technique. Pressure effects caused by both air and nitrogen have been investigated. The air-broadening coefficients determined in this study agree well with the values in the 1996 HITRAN database; ratios and standard deviations of the ratios of the present air-broadening measurements to the 1996 HITRAN values for the two laser bands are: 1.005(15) for laser band I and 1.005(14) for laser band II. Broadening by nitrogen is 3 to 4% larger than that of air. The pressure-induced line shift coefficients are found to be transition dependent and different for the P- and R-branch lines with same J" value. No noticeable differences in the shift coefficients caused by air and nitrogen were found. The results obtained are compared with available values previously reported in the literature.

46 CFR 154.701 - Cargo pressure and temperature control: General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo pressure and temperature control: General. 154.701... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control: General...

46 CFR 154.701 - Cargo pressure and temperature control: General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Cargo pressure and temperature control: General. 154.701... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control: General...

46 CFR 154.701 - Cargo pressure and temperature control: General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Cargo pressure and temperature control: General. 154.701... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control: General...

46 CFR 154.701 - Cargo pressure and temperature control: General.

Code of Federal Regulations, 2010 CFR

2010-10-01

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

46 CFR 154.701 - Cargo pressure and temperature control: General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Cargo pressure and temperature control: General. 154.701... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control: General...

High Pressure Composite Overwrapped Pressure Vessel (COPV) Development Tests at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Ray, David M.; Greene, Nathanael J.; Revilock, Duane; Sneddon, Kirk; Anselmo, Estelle

2008-01-01

Development tests were conducted to evaluate the performance of 2 COPV designs at cryogenic temperatures. This allows for risk reductions for critical components for a Gaseous Helium (GHe) Pressurization Subsystem for an Advanced Propulsion System (APS) which is being proposed for NASA s Constellation project and future exploration missions. It is considered an advanced system since it uses Liquid Methane (LCH4) as the fuel and Liquid Oxygen (LO2) as the oxidizer for the propellant combination mixture. To avoid heating of the propellants to prevent boil-off, the GHe will be stored at subcooled temperatures equivalent to the LO2 temperature. Another advantage of storing GHe at cryogenic temperatures is that more mass of the pressurized GHe can be charged in to a vessel with a smaller volume, hence a smaller COPV, and this creates a significant weight savings versus gases at ambient temperatures. The major challenge of this test plan is to verify that a COPV can safely be used for spacecraft applications to store GHe at a Maximum Operating Pressure (MOP) of 4,500 psig at 140R to 160R (-320 F to -300 F). The COPVs for these tests were provided by ARDE , Inc. who developed a resin system to use at cryogenic conditions and has the capabilities to perform high pressure testing with LN2.

Characteristics of a DC-Driven Atmospheric Pressure Air Microplasma Jet

NASA Astrophysics Data System (ADS)

Choi, Jaegu; Matsuo, Keita; Yoshida, Hidekazu; Namihira, Takao; Katsuki, Sunao; Akiyama, Hidenori

2008-08-01

A dc-driven atmospheric pressure air plasma jet has been investigated for some applications, such as local dental treatment, the inner surface treatment of capillaries, stimuli for microorganisms, and the local cleaning of semiconductor devices. The main experimental results are as follows. The discharge in the pulsed mode occurs repetitively despite of the dc input, and the pulsed mode transfers to the continuous mode as the current exceeds a threshold. The measured emission spectrum from the arc column of the air discharge reveals that most energy of activated electrons is used for the excitation of N2 (second positive system bands) and part of the energy for the dissociation of O2. The length of the plasma torch depends on the tube length, inner gap distance, and flow rate. The maximum torch length of about 40 mm is obtained under certain conditions. The spatial distributions of plasma gas temperature are measured and confirmed by the visualization of the gas flow using Schlieren images. Furthermore, surface treatment and decolorization using the generated plasma torch are carried out, focusing on industrial applications.

Experimental validation of Critical Temperature-Pressure theory of scuffing

NASA Astrophysics Data System (ADS)

Lee, Si C.; Chen, Huanliang

1995-07-01

A series of experiments was conducted for validating a newly developed theory of scuffing. The Critical temperature-Pressure (CTP) theory is based on the physisorption behavior of lubricants and is capable of predicting the onset of scuffing failures over a wide range of operating conditions, including the contacts operating in the boundary lubrication and in the partial elastohydrodynamic lubrication (EHL) regimes. According to the CTP theory, failures occur when the contact temperature exceeds a certain critical value which is a function of the lubricant pressure generated by the hydrodynamic action of the EHL contact. A special device capable of simulating the ambient conditions of the partial EHL conjunctions (of contact temperature, pressure, and the lubricant pressure) was constructed. A ball-on-flat type wear tester was put inside a pressure vessel, completely immersed in a highly pressurized bath of mineral oil. The temperature on the flat specimen was gradually increased while the ball was slowly traversed. At a certain critical temmperature, the friction force abruptly jumped indicating the incipiency of the lubrication breakdown. This experiment was repeated for several levels of hydrostatic pressure and the corresponding critical temperatures were obtained. The test results showed an excellent correlation with the newly developed CTP theory.

Dual pressure-dual temperature isotope exchange process

DOEpatents

Babcock, D.F.

1974-02-12

A liquid and a gas stream, each containing a desired isotope, flow countercurrently through two liquid-gas contacting towers maintained at different temperatures and pressures. The liquid is enriched in the isotope in one tower while the gas is enriched within the other and a portion of at least one of the enriched streams is withdrawn from the system for use or further enrichment. The tower operated at the lower temperature is also maintained at the lower pressure to prevent formation of solid solvates. Gas flow between the towers passes through an expander-compressor apparatas to recover work from the expansion of gas to the lower pressure and thereby compress the gas returning to the tower of higher pressure. (Official Gazette)

Variability of Winter Air Temperature in Mid-Latitude Europe

NASA Technical Reports Server (NTRS)

Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

2002-01-01

The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

Pressure and Temperature Sensitive Paint Field System

NASA Technical Reports Server (NTRS)

Sprinkle, Danny R.; Obara, Clifford J.; Amer, Tahani R.; Faulcon, Nettie D.; Carmine, Michael T.; Burkett, Cecil G.; Pritchard, Daniel W.; Oglesby, Donald M.

2004-01-01

This report documents the Pressure and Temperature Sensitive Paint Field System that is used to provide global surface pressure and temperature measurements on models tested in Langley wind tunnels. The system was developed and is maintained by Global Surface Measurements Team personnel of the Data Acquisition and Information Management Branch in the Research Facilities Services Competency. Descriptions of the system hardware and software are presented and operational procedures are detailed.

Subsonic tests of an all-flush-pressure-orifice air data system

NASA Technical Reports Server (NTRS)

Larson, T. J.; Siemers, P. M., III

1981-01-01

The use of an all-flush-pressure-orifice array as a subsonic air data system was evaluated in flight and wind tunnel tests. Two orifice configurations were investigated. Both used orifices arranged in a cruciform pattern on the airplane nose. One configuration also used orifices on the sides of the fuselage for a source of static pressure. The all-nose-orifice configuration was similar to the shuttle entry air data system (SEADS). The flight data were obtained with a KC-135A airplane. The wind tunnel data were acquired with a 0.035-scale model of the KC-135A airplane. With proper calibration, several orifices on the vertical centerline of the vehicle's nose were found to be satisfactory for the determination of total pressure and angle of attack. Angle of sideslip could be accurately determined from pressure measurements made on the horizontal centerline of the aircraft. Orifice pairs were also found that provided pressure ratio relationships suitable for the determination of Mach number. The accuracy that can be expected for the air data determined with SEADS during subsonic orbiter flight is indicated.

Air breathing in the Arctic: influence of temperature, hypoxia, activity and restricted air access on respiratory physiology of the Alaska blackfish Dallia pectoralis.

PubMed

Lefevre, Sjannie; Damsgaard, Christian; Pascale, Desirae R; Nilsson, Göran E; Stecyk, Jonathan A W

2014-12-15

The Alaska blackfish (Dallia pectoralis) is an air-breathing fish native to Alaska and the Bering Sea islands, where it inhabits lakes that are ice-covered in the winter, but enters warm and hypoxic waters in the summer to forage and reproduce. To understand the respiratory physiology of this species under these conditions and the selective pressures that maintain the ability to breathe air, we acclimated fish to 5°C and 15°C and used respirometry to measure: standard oxygen uptake (Ṁ(O₂)) in normoxia (19.8 kPa P(O₂)) and hypoxia (2.5 kPa), with and without access to air; partitioning of standard Ṁ(O₂) in normoxia and hypoxia; maximum Ṁ(O₂) and partitioning after exercise; and critical oxygen tension (P(crit)). Additionally, the effects of temperature acclimation on haematocrit, haemoglobin oxygen affinity and gill morphology were assessed. Standard Ṁ(O₂) was higher, but air breathing was not increased, at 15°C or after exercise at both temperatures. Fish acclimated to 5°C or 15°C increased air breathing to compensate and fully maintain standard Ṁ(O₂) in hypoxia. Fish were able to maintain Ṁ(O₂) through aquatic respiration when air was denied in normoxia, but when air was denied in hypoxia, standard Ṁ(O₂) was reduced by ∼30-50%. P(crit) was relatively high (5 kPa) and there were no differences in P(crit), gill morphology, haematocrit or haemoglobin oxygen affinity at the two temperatures. Therefore, Alaska blackfish depends on air breathing in hypoxia and additional mechanisms must thus be utilised to survive hypoxic submergence during the winter, such as hypoxia-induced enhancement in the capacities for carrying and binding blood oxygen, behavioural avoidance of hypoxia and suppression of metabolic rate. © 2014. Published by The Company of Biologists Ltd.

Aerodynamic effect of combustor inlet-air pressure on fuel jet atomization

NASA Technical Reports Server (NTRS)

Ingebo, R. D.

1984-01-01

Mean drop diameters were measured with a recently developed scanning radiometer in a study of the atomization of liquid jets injected cross stream in high velocity and high pressure airflows. At constant inlet air pressure, reciprocal mean drop diameter, was correlated with airflow mass velocity. Over a combustor inlet-air pressure range of 1 to 21 atmospheres, the ratio of orifice to mean drop diameter, D(O)/D(M), was correlated with the product of Weber and Reynolds number, WeRe, and with the molecular scale momentum transfer ratio of gravitational to inertial forces.

Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

NASA Astrophysics Data System (ADS)

Wang, K.; Li, Y.; Wang, X.; Yuan, M.

2013-12-01

Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

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

Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong

2015-07-15

Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at framemore » rates up to ∼10{sup 5} frames/second (fps) in air and up to ∼10{sup 4} fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.« less

X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press.

PubMed

Kono, Yoshio; Kenney-Benson, Curtis; Shibazaki, Yuki; Park, Changyong; Wang, Yanbin; Shen, Guoyin

2015-07-01

Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼10(5) frames/second (fps) in air and up to ∼10(4) fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.

WETAIR: A computer code for calculating thermodynamic and transport properties of air-water mixtures

NASA Technical Reports Server (NTRS)

Fessler, T. E.

1979-01-01

A computer program subroutine, WETAIR, was developed to calculate the thermodynamic and transport properties of air water mixtures. It determines the thermodynamic state from assigned values of temperature and density, pressure and density, temperature and pressure, pressure and entropy, or pressure and enthalpy. The WETAIR calculates the properties of dry air and water (steam) by interpolating to obtain values from property tables. Then it uses simple mixing laws to calculate the properties of air water mixtures. Properties of mixtures with water contents below 40 percent (by mass) can be calculated at temperatures from 273.2 to 1497 K and pressures to 450 MN/sq m. Dry air properties can be calculated at temperatures as low as 150 K. Water properties can be calculated at temperatures to 1747 K and pressures to 100 MN/sq m. The WETAIR is available in both SFTRAN and FORTRAN.

High-pressure high-temperature phase diagram of organic crystal paracetamol

DOE PAGES

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

2016-01-06

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

High-pressure high-temperature phase diagram of organic crystal paracetamol

NASA Astrophysics Data System (ADS)

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

2016-01-01

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

Pressure in isochoric systems containing aqueous solutions at subzero Centigrade temperatures.

PubMed

Ukpai, Gideon; Năstase, Gabriel; Șerban, Alexandru; Rubinsky, Boris

2017-01-01

Preservation of biological materials at subzero Centigrade temperatures, cryopreservation, is important for the field of tissue engineering and organ transplantation. Our group is studying the use of isochoric (constant volume) systems of aqueous solution for cryopreservation. Previous studies measured the pressure-temperature relations in aqueous isochoric systems in the temperature range from 0°C to - 20°C. The goal of this study is to expand the pressure-temperature measurement beyond the range reported in previous publications. To expand the pressure-temperature measurements beyond the previous range, we have developed a new isochoric device capable of withstanding liquid nitrogen temperatures and pressures of up to 413 MPa. The device is instrumented with a pressure transducer than can monitor and record the pressures in the isochoric chamber in real time. Measurements were made in a temperature range from - 5°C to liquid nitrogen temperatures for various solutions of pure water and Me2SO (a chemical additive used for protection of biological materials in a frozen state and for vitrification (glass formation) of biological matter). Undissolved gaseous are is carefully removed from the system. Temperature-pressure data from - 5°C to liquid nitrogen temperature for pure water and other solutions are presented in this study. Following are examples of some, temperature-pressure values, that were measured in an isochoric system containing pure water: (- 20°C, 187 MPa); (-25°C, 216 MPa); (- 30°C, 242.3 MPa); (-180°C, 124 MPa). The data is consistent with the literature, which reports that the pressure and temperature at the triple point, between ice I, ice III and water is, - 21.993°C and 209.9 MPa, respectively. It was surprising to find that the pressure in the isochoric system increases at temperatures below the triple point and remains high to liquid nitrogen temperatures. Measurements of pressure-temperature relations in solutions of pure water and Me2

Pressure in isochoric systems containing aqueous solutions at subzero Centigrade temperatures

PubMed Central

Șerban, Alexandru; Rubinsky, Boris

2017-01-01

Objective Preservation of biological materials at subzero Centigrade temperatures, cryopreservation, is important for the field of tissue engineering and organ transplantation. Our group is studying the use of isochoric (constant volume) systems of aqueous solution for cryopreservation. Previous studies measured the pressure-temperature relations in aqueous isochoric systems in the temperature range from 0°C to – 20°C. The goal of this study is to expand the pressure-temperature measurement beyond the range reported in previous publications. Materials and methods To expand the pressure-temperature measurements beyond the previous range, we have developed a new isochoric device capable of withstanding liquid nitrogen temperatures and pressures of up to 413 MPa. The device is instrumented with a pressure transducer than can monitor and record the pressures in the isochoric chamber in real time. Measurements were made in a temperature range from – 5°C to liquid nitrogen temperatures for various solutions of pure water and Me2SO (a chemical additive used for protection of biological materials in a frozen state and for vitrification (glass formation) of biological matter). Undissolved gaseous are is carefully removed from the system. Results Temperature-pressure data from – 5°C to liquid nitrogen temperature for pure water and other solutions are presented in this study. Following are examples of some, temperature-pressure values, that were measured in an isochoric system containing pure water: (- 20°C, 187 MPa); (-25°C, 216 MPa); (- 30°C, 242.3 MPa); (-180°C, 124 MPa). The data is consistent with the literature, which reports that the pressure and temperature at the triple point, between ice I, ice III and water is, - 21.993°C and 209.9 MPa, respectively. It was surprising to find that the pressure in the isochoric system increases at temperatures below the triple point and remains high to liquid nitrogen temperatures. Measurements of pressure-temperature

O and temperature in high-pressure and -temperature gases

NASA Astrophysics Data System (ADS)

Goldenstein, C. S.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

2014-09-01

The design and validation of a tunable diode laser (TDL) sensor for temperature and H2O in high-pressure and -temperature gases are presented. High-fidelity measurements are enabled through the use of: (1) strong H2O fundamental-band absorption near 2.5 μm, (2) calibration-free first-harmonic-normalized wavelength-modulation spectroscopy with second-harmonic detection (WMS-2 f/1 f), (3) an experimentally derived and validated spectroscopic database, and (4) a new approach to selecting the optimal wavelength and modulation depth of each laser. This sensor uses two TDLs near 2,474 and 2,482 nm that were fiber coupled in free space and frequency multiplexed to enable measurements along a single line-of-sight. The lasers were modulated at 35 and 45.5 kHz, respectively, to achieve a sensor bandwidth of 4.5 kHz. This sensor was validated in a shock tube at temperatures and pressures ranging from 1,000 to 2,700 K and 8 to 50 bar. There the sensor resolved transients and recovered the known steady-state temperature and H2O mole fraction with a precision of 3.2 and 2.6 % RMS, respectively.

Amorphization of Serpentine at High Pressure and High Temperature

PubMed

Irifune; Kuroda; Funamori; Uchida; Yagi; Inoue; Miyajima

1996-06-07

Pressure-induced amorphization of serpentine was observed at temperatures of 200° to 300°C and pressures of 14 to 27 gigapascals with a combination of a multianvil apparatus and synchrotron radiation. High-pressure phases then crystallized rapidly when the temperature was increased to 400°C. These results suggest that amorphization of serpentine is an unlikely mechanism for generating deep-focus earthquakes, as the temperatures of subducting slabs are significantly higher than those of the rapid crystallization regime.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2017-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-2018, https://www.eustaceproject.eu) we have developed an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. This includes developing new "Big Data" analysis methods as the data volumes involved are considerable. We will present recent progress along this road in the EUSTACE project, i.e.: • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

Can air temperature be used to project influences of climate change on stream temperature?

USGS Publications Warehouse

Arismendi, Ivan; Safeeq, Mohammad; Dunham, Jason B.; Johnson, Sherri L.

2014-01-01

Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability of model parameters in a suite of regulated and unregulated streams with 11–44 years of stream temperature data. Although such models may have validity when predicting stream temperatures within the span of time that corresponds to the data used to develop them, model predictions did not transfer well to other time periods. Validation of model predictions of most recent stream temperatures, based on air temperature–stream temperature relationships from previous time periods often showed poor performance when compared with observed stream temperatures. Overall, model predictions were less robust in regulated streams and they frequently failed in detecting the coldest and warmest temperatures within all sites. In many cases, the magnitude of errors in these predictions falls within a range that equals or exceeds the magnitude of future projections of climate-related changes in stream temperatures reported for the region we studied (between 0.5 and 3.0 °C by 2080). The limited ability of regression-based statistical models to accurately project stream temperatures over time likely stems from the fact that underlying processes at play, namely the heat budgets of air and water, are distinctive in each medium and vary among localities and through time.

Respiratory and Laryngeal Responses to an Oral Air Pressure Bleed during Speech

ERIC Educational Resources Information Center

Huber, Jessica E.; Stathopoulos, Elaine T.

2003-01-01

Researchers have hypothesized that the respiratory and laryngeal speech subsystems would respond to an air pressure bleed, but these responses have not been empirically studied. The present study examined the nature of the responses of the respiratory and laryngeal subsystems to an air pressure bleed in order to provide information relevant to the…

Effects of Ambient Temperature and Forced-air Warming on Intraoperative Core Temperature: A Factorial Randomized Trial.

PubMed

Pei, Lijian; Huang, Yuguang; Xu, Yiyao; Zheng, Yongchang; Sang, Xinting; Zhou, Xiaoyun; Li, Shanqing; Mao, Guangmei; Mascha, Edward J; Sessler, Daniel I

2018-05-01

The effect of ambient temperature, with and without active warming, on intraoperative core temperature remains poorly characterized. The authors determined the effect of ambient temperature on core temperature changes with and without forced-air warming. In this unblinded three-by-two factorial trial, 292 adults were randomized to ambient temperatures 19°, 21°, or 23°C, and to passive insulation or forced-air warming. The primary outcome was core temperature change between 1 and 3 h after induction. Linear mixed-effects models assessed the effects of ambient temperature, warming method, and their interaction. A 1°C increase in ambient temperature attenuated the negative slope of core temperature change 1 to 3 h after anesthesia induction by 0.03 (98.3% CI, 0.01 to 0.06) °Ccore/(h°Cambient) (P < 0.001), for patients who received passive insulation, but not for those warmed with forced-air (-0.01 [98.3% CI, -0.03 to 0.01] °Ccore/[h°Cambient]; P = 0.40). Final core temperature at the end of surgery increased 0.13°C (98.3% CI, 0.07 to 0.20; P < 0.01) per degree increase in ambient temperature with passive insulation, but was unaffected by ambient temperature during forced-air warming (0.02 [98.3% CI, -0.04 to 0.09] °Ccore/°Cambient; P = 0.40). After an average of 3.4 h of surgery, core temperature was 36.3° ± 0.5°C in each of the forced-air groups, and ranged from 35.6° to 36.1°C in passively insulated patients. Ambient intraoperative temperature has a negligible effect on core temperature when patients are warmed with forced air. The effect is larger when patients are passively insulated, but the magnitude remains small. Ambient temperature can thus be set to comfortable levels for staff in patients who are actively warmed.

High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

NASA Technical Reports Server (NTRS)

Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

2014-01-01

Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Rayner, Nick

2017-04-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project: 1. providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; 2. identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; 3. estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; 4. using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2016-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project, i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection.

PubMed

Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K

2015-10-15

A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

Temperature-(208-318 K) and pressure-(18-696 Torr) dependent rate coefficients for the reaction between OH and HNO3

NASA Astrophysics Data System (ADS)

Dulitz, Katrin; Amedro, Damien; Dillon, Terry J.; Pozzer, Andrea; Crowley, John N.

2018-02-01

Rate coefficients (k5) for the title reaction were obtained using pulsed laser photolytic generation of OH coupled to its detection by laser-induced fluorescence (PLP-LIF). More than 80 determinations of k5 were carried out in nitrogen or air bath gas at various temperatures and pressures. The accuracy of the rate coefficients obtained was enhanced by in situ measurement of the concentrations of both HNO3 reactant and NO2 impurity. The rate coefficients show both temperature and pressure dependence with a rapid increase in k5 at low temperatures. The pressure dependence was weak at room temperature but increased significantly at low temperatures. The entire data set was combined with selected literature values of k5 and parameterised using a combination of pressure-dependent and -independent terms to give an expression that covers the relevant pressure and temperature range for the atmosphere. A global model, using the new parameterisation for k5 rather than those presently accepted, indicated small but significant latitude- and altitude-dependent changes in the HNO3 / NOx ratio of between -6 and +6 %. Effective HNO3 absorption cross sections (184.95 and 213.86 nm, units of cm2 molecule-1) were obtained as part of this work: σ213.86 = 4.52-0.12+0.23 × 10-19 and σ184.95 = 1.61-0.04+0.08 × 10-17.

N Vibrational Temperatures and OH Number Density Measurements in a NS Pulse Discharge Hydrogen-Air Plasmas

NASA Astrophysics Data System (ADS)

Hung, Yichen; Winters, Caroline; Jans, Elijah R.; Frederickson, Kraig; Adamovich, Igor V.

2017-06-01

This work presents time-resolved measurements of nitrogen vibrational temperature, translational-rotational temperature, and absolute OH number density in lean hydrogen-air mixtures excited in a diffuse filament nanosecond pulse discharge, at a pressure of 100 Torr and high specific energy loading. The main objective of these measurements is to study a possible effect of nitrogen vibrational excitation on low-temperature kinetics of HO2 and OH radicals. N2 vibrational temperature and gas temperature in the discharge and the afterglow are measured by ns broadband Coherent Anti-Stokes Scattering (CARS). Hydroxyl radical number density is measured by Laser Induced Fluorescence (LIF) calibrated by Rayleigh scattering. The results show that the discharge generates strong vibrational nonequilibrium in air and H2-air mixtures for delay times after the discharge pulse of up to 1 ms, with peak vibrational temperature of Tv ≈ 2000 K at T ≈ 500 K. Nitrogen vibrational temperature peaks ≈ 200 μs after the discharge pulse, before decreasing due to vibrational-translational relaxation by O atoms (on the time scale of a few hundred μs) and diffusion (on ms time scale). OH number density increases gradually after the discharge pulse, peaking at t 100-300 μs and decaying on a longer time scale, until t 1 ms. Both OH rise time and decay time decrease as H2 fraction in the mixture is increased from 1% to 5%. OH number density in a 1% H2-air mixture peaks at approximately the same time as vibrational temperature in air, suggesting that OH kinetics may be affected by N2 vibrational excitation. However, preliminary kinetic modeling calculations demonstrate that OH number density overshoot is controlled by known reactions of H and O radicals generated in the plasma, rather than by dissociation by HO2 radical in collisions with vibrationally excited N2 molecules, as has been suggested earlier. Additional measurements at higher specific energy loadings and kinetic modeling

Aerodynamic effect of combustor inlet-air pressure on fuel jet atomization

NASA Technical Reports Server (NTRS)

Ingebo, R. D.

1984-01-01

Mean drop diameters were measured with a recently developed scanning radiometer in a study of the atomization of liquid jets injected cross stream in high velocity and high pressure airflows. At constant inlet air pressure, reciprocal mean drop diameter was correlated with airflow mass velocity. Over a combustor inlet-air pressure range of 1 to 21 atmospheres, the ratio of orifice to mean drop diameter, D(O)/D(M), was correlated with the product of Weber and Reynolds number, WeRe, and with the molecular scale momentum transfer ratio of gravitational to inertial forces. Previously announced in STAR as N84-22910

Sensitivity of New England Stream Temperatures to Air Temperature and Precipitation Under Projected Climate

NASA Astrophysics Data System (ADS)

Huang, T.; Samal, N. R.; Wollheim, W. M.; Stewart, R. J.; Zuidema, S.; Prousevitch, A.; Glidden, S.

2015-12-01

The thermal response of streams and rivers to changing climate will influence aquatic habitat. This study examines the impact that changing climate has on stream temperatures in the Merrimack River, NH/MA USA using the Framework for Aquatic Modeling in the Earth System (FrAMES), a spatially distributed river network model driven by air temperature, air humidity, wind speed, precipitation, and solar radiation. Streamflow and water temperatures are simulated at a 45-second (latitude x longitude) river grid resolution for 135 years under historical and projected climate variability. Contemporary streamflow (Nash-Sutcliffe Coefficient = 0.77) and river temperatures (Nash-Sutcliffe Coefficient = 0.89) matched at downstream USGS gauge data well. A suite of model runs were made in combination with uniformly increased daily summer air temperatures by 2oC, 4 oC and 6 oC as well as adjusted precipitation by -40%, -30%, -20%, -10% and +10% as a sensitivity analysis to explore a broad range of potential future climates. We analyzed the summer stream temperatures and the percent of river length unsuitable for cold to warm water fish habitats. Impacts are greatest in large rivers due to the accumulation of river temperature warming throughout the entire river network. Cold water fish (i.e. brook trout) are most strongly affected while, warm water fish (i.e. largemouth bass) aren't expected to be impacted. The changes in stream temperatures under various potential climate scenarios will provide a better understanding of the specific impact that air temperature and precipitation have on aquatic thermal regimes and habitat.

Effect of water temperature and air stream velocity on performance of direct evaporative air cooler for thermal comfort

NASA Astrophysics Data System (ADS)

Aziz, Azridjal; Mainil, Rahmat Iman; Mainil, Afdhal Kurniawan; Listiono, Hendra

2017-01-01

The aim of this work was to determine the effects of water temperature and air stream velocity on the performance of direct evaporative air cooler (DEAC) for thermal comfort. DEAC system requires the lower cost than using vapor compression refrigeration system (VCRS), because VCRS use a compressor to circulate refrigerant while DEAC uses a pump for circulating water in the cooling process to achieve thermal comfort. The study was conducted by varying the water temperature (10°C, 20°C, 30°C, 40°C, and 50°C) at different air stream velocity (2,93 m/s, 3.9 m/s and 4,57 m/s). The results show that the relative humidity (RH) in test room tends to increase with the increasing of water temperature, while on the variation of air stream velocity, RH remains constant at the same water temperature, because the amount of water that evaporates increase with the increasing water temperature. The cooling effectiveness (CE) increase with the increasing of air stream velocity where the higher CE was obtained at lower water temperature (10°C) with high air velocity (4,57m/s). The lower room temperature (26°C) was achieved at water temperature 10°C and air stream velocity 4.57 m/s with the relative humidity 85,87%. DEAC can be successfully used in rooms that have smoothly air circulation to fulfill the indoor thermal comfort.

Multi-stage versus single-stage inflation and deflation cycle for alternating low pressure air mattresses to prevent pressure ulcers in hospitalised patients: a randomised-controlled clinical trial.

PubMed

Demarré, L; Beeckman, D; Vanderwee, K; Defloor, T; Grypdonck, M; Verhaeghe, S

2012-04-01

The duration and the amount of pressure and shear must be reduced in order to minimize the risk of pressure ulcer development. Alternating low pressure air mattresses with multi-stage inflation and deflation cycle of the air cells have been developed to relieve pressure by sequentially inflating and deflating the air cells. Evidence about the effectiveness of this type of mattress in clinical practice is lacking. This study aimed to compare the effectiveness of an alternating low pressure air mattress that has a standard single-stage inflation and deflation cycle of the air cells with an alternating low pressure air mattress with multi-stage inflation and deflation cycle of the air cells. A randomised controlled trial was performed in a convenience sample of 25 wards in five hospitals in Belgium. In total, 610 patients were included and randomly assigned to the experimental group (n=298) or the control group (n=312). In the experimental group, patients were allocated to an alternating low pressure air mattress with multi-stage inflation and deflation cycle of the air cells. In the control group, patients were allocated to an alternating low pressure air mattress with a standard single-stage inflation and deflation cycle of the air cells. The outcome was defined as cumulative pressure ulcer incidence (Grade II-IV). An intention-to-treat analysis was performed. There was no significant difference in cumulative pressure ulcer incidence (Grade II-IV) between both groups (Exp.=5.7%, Contr.=5.8%, p=0.97). When patients developed a pressure ulcer, the median time was 5.0 days in the experimental group (IQR=3.0-8.5) and 8.0 days in the control group (IQR=3.0-8.5) (Mann-Whitney U-test=113, p=0.182). The probability to remain pressure ulcer free during the observation period in this trial did not differ significantly between the experimental group and the control group (log-rank χ(2)=0.013, df=1, p=0.911). An alternating low pressure air mattress with multi-stage inflation