Showing papers on "Atmospheric pressure published in 1982"
TL;DR: Calculations with a numerical model of the atmosphere show that the global fields of rainfall, temperature, and motion strongly depend on the land- surface evapotranspiration.
Abstract: Land-surface evapotranspiration is shown to strongly influence global fields of rainfall, temperature and motion by calculations using a numerical model of the atmosphere, confirming the general belief in the importance of evapotranspiration-producing surface vegetation for the earth's climate. The current version of the Goddard Laboratory atmospheric general circulation model is used in the present experiment, in which conservation equations for mass, momentum, moisture and energy are expressed in finite-difference form for a spherical grid to calculate (1) surface pressure field evolution, and (2) the wind, temperature, and water vapor fields at nine levels between the surface and a 20 km height.
1,100 citations
TL;DR: High-sensitivity measurements of infrared absorptions due to isolated lines broadened by air at atmospheric pressure are reported, and techniques for further increasing sensitivity are discussed.
Abstract: High-sensitivity measurements of infrared absorptions due to isolated lines broadened by air at atmospheric pressure are reported. Tunable diode lasers and harmonic techniques were employed to detect absorptions as small as 0.01% over path lengths up to 250 m through the open air. The limiting noise source is caused by a base line signal which varies with the optical alignment. The reported sensitivity is not a fundamental limit. Techniques for further increasing sensitivity are discussed.
225 citations
TL;DR: In this paper, an experimental situation is briefly described and an estimate is made of the best values at 298.15 K and atmospheric pressure, which is used to judge the results of work on the temperature and pressure dependence of D.
Abstract: Results on tracer and self-diffusion coefficients D of the various isotopic species of water as reported in the literature vary widely. The experimental situation is briefly described and an estimate is made of the best values at 298.15 K and atmospheric pressure. The conclusions are used to judge the results of work on the temperature and pressure dependence of D. A brief account on isotopic effects on tracer and self diffusion in water is given.
161 citations
TL;DR: In this paper, the authors extended the theory of wobble excitation for a non-rigid earth to include the effects of the earth's fluid core and of the rotationally induced pole tide in the ocean.
Abstract: Summary The theory of wobble excitation for a non-rigid earth is extended to include the effects of the earth's fluid core and of the rotationally induced pole tide in the ocean. The response of the solid earth and oceans to atmospheric loading is also considered. The oceans are shown to be affected by changes in the gravitational potential which accompany atmospheric pressure disturbances and by the load-induced deformation of the solid earth. These various improvements affect the excitation equations by about 10 per cent. Atmospheric and oceanic excitation can be computed using either an angular momentum or a torque approach. We use the dynamical equations for a thin fluid to relate these two methods and to develop a more general, combined approach. Finally, geostrophic winds and currents are shown to be potentially important sources of wobble excitation, in contrast to what is generally believed.
155 citations
TL;DR: In this paper, it was shown that thin film single crystal layers of ZnS, ZnSe and ZnSE x Se 1-x can be grown on a variety of substrates by direct reaction at atmospheric pressure, of dimethyl zinc, hydrogen sulphide and/or hydrogen selenide, using hydrogen as the carrier gas.
151 citations
TL;DR: In this paper, the authors measured explosion cell dimensions at an initial pressure of ∼10 5 Pa (1 atm) for stoichiometric mixtures with air for hydrogen, acetylene, ethylene, and ethane in a rectangular detonation tube of dimensions 76 mm × 38 mm using the sooted plated technique.
124 citations
01 Jan 1982
TL;DR: In this article, the hypervelocity impact (1.25-6 km/s) of projectiles into water overlying unconsolidated strata is reported for a variety of water depths.
Abstract: The hypervelocity impact (1.25-6 km/s) of projectiles into water overlying unconsolidated strata is reported for a variety of water depths. Variation of the background atmospheric pressure is found to be an important additional parameter. The relation of these exploratory experiments to pelagic impact of asteroidal-sized objects is discussed from the standpoint of atmospheric injection of sea water, the modification of bottom (benthic) topography, and the generation of a field of mega-amplitude sea waves and their propagation away from the source.
110 citations
TL;DR: In this paper, the rotational transfer rate constant for NO is estimated to be ⩾4×109−1 in the flame, corresponding to a cross section of ∼70 A2.
Abstract: Molecular multiphoton ionization experiments are reported for the first time in a flame environment. The resonantly enhanced two‐photon photoionization spectrum of NO from 270 to 317 nm in an atmospheric pressure H2/air/N2O flame is essentially identical with respect to both line position and intensity to that which is predicted for the one‐photon absorption to the intermediate A state. A model is developed here which accounts for this result by including rates for collisional repopulation of the laser depleted state. Based on this model, the rotational transfer rate constant for NO is estimated to be ⩾4×109 s−1 in the flame, corresponding to a cross section of ∼70 A2. It is found that the photoionization spectra obtained in this work have far better signal‐to‐noise and resolution than those reported for NO in flames using laser‐induced fluorescence methods and that the estimated detection limit for NO is 1 ppm.
108 citations
TL;DR: In this article, the influence of temperature, partial pressure of oxygen and quenching speed on the decomposition rate of magnetite (Fe3O4) is presented, and it is shown that at atmospheric pressure, high yields are obtained from the condensed vapours in the temperature range 900-1500°C.
106 citations
TL;DR: In this article, an exponential dependence of particle flux with height above the surface was found independent of windspeed and particle size, which was verified by a theoretical force ration balance of spin to drag force.
96 citations
TL;DR: In this paper, an experimental study of the critical heat flux has been carried out for natural convective boiling at atmospheric pressure in vertical rectangular channels, in which four kinds of test liquids (water, ethanol, freon 113, and benzene) have been made for the ratio l/s less than 120.
Abstract: An experimental study of the critical heat flux has been carried out for natural convective boiling at atmospheric pressure in vertical rectangular channels. Experiments in four kinds of test liquids (water, ethanol, freon 113, and benzene) have been made for the ratio l/s less than 120, in which l is the length of the heated surface and s is the width of the channels. A generalized correlation for the critical heat-flux data in the four test liquids is evolved.
TL;DR: The crystal growth of black phosphorus (B.P.) and its electrical properties have been studied at high pressures and high temperatures as discussed by the authors, where a wedge type cubic anvil high pressure apparatus was used in the present experiments.
Abstract: The crystal growth of black phosphorus(B.P.) and its electrical properties have been studied at high pressures and high temperatures. A wedge type cubic anvil high pressure apparatus was used in the present experiments. From the measurement of the electrical resistance the melting points of B.P. have determined at high pressures. When B.P. is melted in the carbon furnace and slowly cools at 2.3 GPa, the large single crystals have often been grown. The size of the largest one is 4 mm in diameter and 5 mm in length. The anisotropic resistivity within the layers(ac-plane) has been observed. The resistivities along the a-, c- and b(perpendicular to the layer)-axes were about 0.1, ∼1 and 102∼103 Ωcm, respectively at atmospheric pressure. The resistivity along the a-axis was insensitive to pressure; on the other hand, the resistivities along the c- and b- axes decreased rapidly with increasing pressure at room temperature. The resistivity along the b-axis was about two orders of magnitudes larger than ...
Abstract: A newly developed model to predict chemical compatibilities in waterflood operations is described. The model calculates the coprecipitation of BaSO/sub 4/, SrSO/sub 4/, and CaSO/sub 4/ at various locations in field operations as mixtures of injection and reservoir waters flow through injection wells, reservoir, and production wells into surface facilities. As its data base, the model uses comprehensive data of actually measured solubilities in fairly complex oilfield and geothermal brines at various temperatures and at saturation or atmospheric pressure. The solubilities at high pressures are calculated using thermodynamic parameters. The application of the model is illustrated by examples involving two reservoir and two injection waters. 19 refs.
TL;DR: In this paper, a model is developed to describe the effects of local and global atmospheric pressure fluctuations on local gravity and techniques for the removal of random pressure variations from gravity records are described.
Abstract: Summary. A model is developed to describe the effects of local and global atmospheric pressure fluctuations on local gravity. The calculated admittance of gravity to the pressure tides S1-S4 at Pinon Flat, California is compared to those measured using the superconducting gravimeter. The theoretical and measured admittances are in good agreement for the S3 and S4 tides. The difference between theory and observation at S2 can probably be explained by the ocean tide at that frequency while the discrepancy at S1 remains unexplained. Techniques for the removal of random pressure variations from gravity records are described. Using statistics derived from spherical harmonic decompositions of the Earth's pressure field, it is shown that more than 80 per cent of the pressure induced gravity variations should be removed from a gravity record by employing a single barometer and least-squares procedure. It is further shown that adding a ring of barometers should increase the effectiveness to about 90 per cent. The amount of barometric pressure ‘noise’ which remains after subtracting the simultaneous record of two gravimeters is calculated as a function of their separation and indicates that significantly less noise is present in the difference than in the individual records for separations of up to 17° of arc.
TL;DR: In this article, the concentration of lhe OH radical in a stoichiometric methane-air flat flame at atmospheric pressure was measured with both laser-absorption spectroscopy and molecular-beam mass spectrometry (MBMS).
Abstract: The concentration of lhe OH radical in a stoichiometric methane-air flat flame at atmospheric pressure was measured with both laser-absorption spectroscopy and molecular-beam mass spectrometry (MBMS). The nonequilibrium peak OH concentrations and the OH decay rate measured from the two techniques were in good agreement. The OH profile from the MBMS measurements, however, was shifted downstream from the absorption measurements by the MBMS sampling process. A comparison of temperature profiles from thermocouple measurements and from a molecular-beam time-of-flight technique exhibited a similar downstream shift. The MBMS measurements effectively sampled the gas properties approximately five orifice diameters ahead of the sampling-probe tip. Perturbation of the OH concentration profile using various sampling probes indicate the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling.
TL;DR: In this paper, the value of exospheric temperature in the equatorial region to be 800 (+150, -120) K at an altitude of 1540 km above the 1-bar atmospheric pressure level; the H2-density at 15 40 km is determined to be 5 (+3.6, -1.8) x 10 to the 9th per cu cm.
Abstract: Occultation of the star Delta-Scorpii by Saturn as recorded by the Voyager Ultraviolet Spectrometer yields the value of the exospheric temperature in the equatorial region to be 800 (+150, -120) K at an altitude of 1540 km above the 1-bar atmospheric pressure level; the H2-density at 1540 km is determined to be 5 (+3.6, -1.8) x 10 to the 9th per cu cm. Temperature gradient in the thermosphere is found to be 1.25 (+0.05, -0.07) K/km. Methane volume mixing ratio at 965 km above the 1-bar pressure level is determined to be 0.00015.
TL;DR: In this paper, the cavitation zone of a submerged journal bearing was investigated at speeds of 1840 and 3000 rpm, and at each speed, four different levels of the ambient supply pressure were applied, ranging from 13.6 KPa to 54.4 KPa.
Abstract: Visual observations and pressure measurements in the cavitation zone of a submerged journal bearing are described. Tests are run at speeds of 1840 and 3000 rpm, and at each speed, four different levels of the ambient supply pressure are applied, ranging from 13.6 KPa to 54.4 KPa. A strong reverse flow is detected inside the cavitation area adjacent to its downstream end, and significant pressure variations on the order of 50 KPa are found inside the cavitation region at the downstream portion of its circumferential extent. Results indicate that the assumption of a constant cavitation pressure is incorrect in the case of enclosed cavitations, and it is postulated that oil which is saturated with air under atmospheric pressure becomes oversaturated in the subcavity pressure loop.
TL;DR: A model for the Mars atmosphere up to 100 km altitude and between the 60 deg latitudes is presented in this paper, where seasonal variations are considered as induced by variations in surface temperature, using data supplied by the Viking lander and Mars 6 probe.
01 Jan 1982
TL;DR: In this paper, it was shown that combustion occurs only in the bubble phase and not to any significant extent in the particulate phase and that a bubble of fuel and air has to reach a critical size (about 30 mm, depending on bed conditions) before it ignites.
Abstract: Mixtures of propane and air have been used to fluidise a bed of silica sand at atmospheric pressure. Both the ignition and combustion of these gas mixtures have been studied in this situation. It is noteworthy that high temperatures (ca. 800°C) have to be reached before bubbles of propane and air ignite within the bed. The indications are that combustion occurs only in the bubble phase and not to any significant extent in the particulate phase. Moreover, it appears that a bubble of fuel and air has to reach a critical size (about 30 mm, depending on bed conditions) before it ignites. This is because ignition is controlled by a balance between near-isothermal chain branching and rapid removal of radicals from a bubble by gas circulating to the surrounding sand particles where radical recombination occurs. Analysis of the size of bubbles igniting at various temperatures indicates an activation energy for the chain branching step of around 254 kJ/mol. In addition, a correlation due to Darton appears preferable to an alternative one for predicting the sizes of gas bubbles in hot fluidised beds.
TL;DR: In this paper, the concentration profiles of NH and OH were measured in an atmospheric pressure, premixed, laminar CH4/N2O flame over a porous-plug, flat flame burner.
TL;DR: A new microwave plasma at atmospheric pressure is described in this paper, which is supported by a surface wave excitation structure called SURFRON, and both argon and helium can be used to sustain the plasma.
Patent•
20 Sep 1982TL;DR: In this article, a novel apparatus for the production of a sustained inductively coupled non-argon plasma discharge in flowing gas in a 13-25 mm containment tube at atmospheric pressure is presented.
Abstract: Disclosed is a novel apparatus for the production of a sustained inductively coupled non-argon plasma discharge in flowing gas in a 13-25 mm (analytical size) containment tube at atmospheric pressure. The apparatus is developed for elemental analysis of injected aerosol or powdered samples, and particularly for air monitoring applications.
TL;DR: In this article, a high pressure differential thermal analysis of the γ form nylon 6 obtained by iodine treatment was performed by means of a wide angle X-ray diffraction measurement.
Abstract: Thermal behavior under high pressure of the γ form nylon 6 obtained by iodine treatment was investigated by means of a high pressure differential thermal analysis. The crystalline structures which resulted in the endo- and exo-thermic peaks in the thermogram were examined with the wide angle X-ray diffraction measurement. Under relatively low pressure (170—2000 kg cm−2), two endothermic peaks were found. With increasing pressure, the lower temperature side endotherm due to the melting of the γ form crystal became small, while the higher one due to the melting of the converted a form crystal became large. Under high pressure (above 2000 kg cm−2) an endotherm due to the melting of the converted α form crystal and an exotherm were observed. This exotherm is attributed to the γ to α form transformation. In this case, the transformation occurred without melting the γ form crystal, in contrast to the situation at atmospheric pressure. The pressure dependences of the melting peak temperatures of the α form and the γ form were almost the same and equal to 18°C per 1000 kg cm−2.
TL;DR: In this paper, a continuous recording accumulator method was employed to study the effect of natural pressure cycles such as due to the passage of cyclonic weather systems on the time-averaged flux of 222Rn from the soil.
Abstract: A continuous recording accumulator method has been employed to study the effect of natural pressure cycles such as due to the passage of cyclonic weather systems on the time-averaged flux of 222Rn from the soil. Results indicate a modest net enhancement of flux (∼10%) for pressure variation with standard deviations on the order of 0.2 in Hg.
TL;DR: In this paper, a review of the literature on vacuum-arc phenomena and the effect of low-pressure gaseous ambients on electrode phenomena in the transition to atmospheric pressure arcs is presented.
Abstract: This paper reviews vacuum-arc phenomena, and the effect of low-pressure gaseous ambients on electrode phenomena in the transition to atmospheric pressure arcs. The 5 main areas addressed are cathode-spot phenomena, anode-spot phenomena, the properties of the interelectrode plasma for both diffuse arcs and columnar arcs, the interaction of vacuum arcs with axial and transverse magnetic fields, and finally, the transition to atmospheric pressure arcs. The current levels range from 50 A to 50 kA. For each of these 5 main areas, features of the vacuum arc which can be reasonably established from the literature are filrst described, followed by a discussion of parameters requiring additional experimental and theoretical study. For example, the current densities, microstructure, and theoretical description of the cathode spot remain the subject of much debate. There is also a need for additional experimental observations of the anode ion flux and ion energies in order to clarify the overall anode-spot mechanism. With respect to high-current columnar arcs, here there is uncertainty concerning the pressure in the arc column and the mechanism of the grossly evaporating cathode spot. It is firmly established that these high-current columnar arcs can be avoided by applying an axial magnetic field parallel to the arcing axis, but a detailed understanding of the magnetic field/arc interaction remains to be established. The review concludes with a discussion of experimental investigations of electrode phenomena in the presence of low ambient gas pressures.
TL;DR: In this paper, the authors presented two phase pressure loss data for angles from vertical upward to vertical downward for co-current air-water flow in a 4.55 cm diameter pipe operating at about atmospheric pressure.
TL;DR: In this paper, high-speed cine photography was used for recording the qualitative aspects of boiling intensity and for obtaining some basic bubble growth data which have not been previously reported, and a qualitative theory for growth of the two-phase droplet was based on assuming that heat for vaporizing the volatile liquid was transferred across a thin thermal boundary layer surrounding the vapor bubble.
Abstract: A study of high-pressure bubble growth within liquid droplets heated to their limits of superheat is reported. Droplets of an organic liquid (n-octane) were heated in an immiscible nonvolatile field liquid (glycerine) until they began to boil. High-speed cine photography was used for recording the qualitative aspects of boiling intensity and for obtaining some basic bubble growth data which have not been previously reported. The intensity of droplet boiling was found to be strongly dependent on ambient pressure. At atmospheric pressure the droplets boiled in a comparatively violent manner. At higher pressures photographic evidence revealed a two-phase droplet configuration consisting of an expanding vapor bubble beneath which was suspended a pool of the vaporizing liquid. A qualitative theory for growth of the two-phase droplet was based on assuming that heat for vaporizing the volatile liquid was transferred across a thin thermal boundary layer surrounding the vapor bubble. Measured droplet radii were found to be in relatively good agreement with predicted radii.
TL;DR: In this paper, an experimental and theoretical study of the difference between the electron temperature Te and the gas temperature Tg in a stationary cylindrical argon plasma was conducted, based on the measurement of a line coefficient, during the first microseconds of plasma decay, which presents a jump due to the equalisation of temperatures.
Abstract: Deals with an experimental and theoretical study of the difference between the electron temperature Te and the gas temperature Tg in a stationary cylindrical argon plasma. The experimental method is based on the measurement of a line coefficient, during the first microseconds of plasma decay, which presents a jump due to the equalisation of temperatures. A theoretical model with rate equations and the electron energy balance has been developed. The comparison between experimental and theoretical values of the difference (Te-Tg) has been carried out for several current intensities and radial positions. The agreement is good for an arc with a 6 mm diameter. For a 4 mm diameter the computed values are less precise than the experimental ones because of the inaccuracy of diffusion terms which play an important part in the computation of (Te-Tg).
TL;DR: In this article, Na2O 3SiO2 glasses with high water content were prepared under high pressure, hydrothermal conditions and their chemical durabilities in water were measured at atmospheric pressure and 30°C.
Abstract: Na2O 3SiO2 glasses with high water content were prepared under high-pressure, hydrothermal conditions and their chemical durabilities in water were measured at atmospheric pressure and 30°C. Chemical durability decreases with increasing water content, which is probably due to a positive dependence of H+ (or H3O+) diffusivity on water content.