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Showing papers on "Total pressure published in 1973"


Journal ArticleDOI
TL;DR: In this paper, a set of equations was derived which allowed the partial pressures of the different molecular species to be calculated as a function of total pressure and temperature, and real gas corrections were included, so that these equations can be used up to 1273 K and the saturation pressure of 144 atm.

145 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that metal, metal vapor pressure, inert gas flow rate, and total pressure is a function of the metal particle size, with prime factors being the transit time from the furnace to the observation region and metal vapor concentration.
Abstract: Plasma‐resonance light scattering has been observed from alkali metal particles condensed from atoms in a flowing inert gas. Lithium, sodium, potassium, rubidium, and cesium vapors were found to spontaneously form particles from 0.5 to more than 200 Torr inert gas pressure. Wavelengths of observed resonances agree with those calculated for spherical particles of 5–50 nm diameter. Using the resonance peak position as an indication of particle size, it has been possible to study the growth of the particles in situ. . Particle size was found to be a function of the metal, metal vapor pressure, inert gas, inert gas flow rate, and total pressure, with prime factors being the transit time from the furnace to the observation region and metal vapor concentration.

63 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a theory to explain the cutting action of water jets having total pressures above 1000 atm, where the surface pressure would suffice to keep the grains in place, but permeability allows the water to penetrate beneath the cutting surface and relieve the pressure across the grains.

46 citations



Journal ArticleDOI
TL;DR: In this article, a pulsed HF chemical laser utilizing the chain reaction between H2 and F2 has been operated with electric discharge initiation, and a uniform transverse discharge is made possible through the use of spark preionization.
Abstract: A pulsed HF chemical laser utilizing the chain reaction between H2 and F2 has been operated with electric discharge initiation. A uniform transverse discharge is made possible through the use of spark preionization. For the mixture 1:1:10:0.06 (F2:H2:He:O2) at 120 Torr total pressure an output energy 1.01 times the electrical input has been achieved. The corresponding chemical efficiency was ∼1.0%. A tradeoff is observed between electrical efficiency and chemical efficiency with the maximum chemical efficiency of 2% being achieved at an electrical efficiency of 25%. Even higher electrical efficiencies are expected with further device optimization.

26 citations


Journal ArticleDOI
TL;DR: In this article, a detailed comparison of four types of electrode structures for HF laser action was made and the HF was produced by transverse discharges through SF 6 /RH mixtures.
Abstract: A detailed comparison of four types of electrode structures for HF laser action was made. The HF was produced by transverse discharges through SF 6 /RH mixtures. The pulse energy, pulse duration, and spectroscopic output were measured as a function of the type of hydrogen donor, its partial pressure as well as the total pressure when He was added. The hydrogen donors used were H 2 , CH 4 , C 2 H 6 , C 3 H 8 , and commercial gasoline.

25 citations


Journal ArticleDOI
TL;DR: In this paper, an e.m.f. method for the investigation of sulphate-oxide equilibria has been applied to the sulphateoxide systems of Mg, Mn, Fe, Ni, Cu and Zn, as well as the equilibrium between the two sulphates of Fe.

25 citations


Patent
06 Dec 1973
TL;DR: In this article, a method and apparatus for removal of acidic gases from a gas stream by contacting the gas stream with an amine vapor in a reaction zone was proposed, and the preferred amines are methylamine and dimethylamine.
Abstract: A method and apparatus for removal of acidic gases from a gas stream by contacting the gas stream with an amine vapor in a reaction zone. The partial pressure of amine vapor in the reaction zone is at least 5 percent of the total pressure therein, resulting in removal of at least 99 percent of the acidic gases. When operating at ambient temperature and substantially atmospheric pressure, preferred amines are methylamine and dimethylamine.

24 citations


Journal ArticleDOI
TL;DR: The gas-dynamical structure of jets of a low-density diatomic gas beyond a sonic nozzle at large pressure drops under conditions of a transition from continuous medium processes to rarefied gas processes is examined in this paper.
Abstract: The gas-dynamical structure of jets of a low-density diatomic gas beyond a sonic nozzle at large pressure drops under conditions of a transition from continuous medium processes to rarefied gas processes is examined on the basis of experimental data obtained in low-density gas-dynamical tubes using electron-beam diagnostics and the Pitot tube method. Isomorphism is shown in the density distribution and total pressure in all cross sections of the jet with respect to pressures at a constant value of the complex RL=R*/N1/2(R* is the Reynolds number in the critical cross section of the nozzle, and N is the ratio of the Pitot pressure and the pressure in the discharge chamber). It is shown on the basis of a comparison of local Reynolds numbers for all zones of the jet that this is an analog complex. The experimental data on the variation in the jet structure are presented as a function of the number RL in the range of 5–600. For RL> 100 the flow in the jet can be considered as continuous; for RL 200 remains subsonic on the axis to a distance of several lengths of the primary cycle. A transition to supersonic velocity on the jet axis can occur with a decrease in the numbers RL owing to ejection acceleration by the supersonic ring-shaped compressed layer.

21 citations


Journal ArticleDOI
TL;DR: In this article, the authors showed that the rate of dehydration is controlled by diffusion of water, and below 478 K the activation energy is 190 kJ mol−1 and this value is not affected by the partial pressure of water vapour.
Abstract: The dehydration of CaHPO4,2H2O has been studied isothermally between 409 and 537 K and over a range of partial pressures of water vapour between 1·3 cN m–2 and 6·0 kN m–2 at a total pressure of 1 atm. The rate of dehydration is controlled by diffusion of water, and below 478 K the activation energy is 190 kJ mol–1 and this value is not affected by the partial pressure of water vapour. However, above 478 K the activation energy drops markedly and is then affected by partial pressure of water vapour. Some evidence has been obtained for the formation of a monohydrate as an intermediate and, while this is not conclusive, this postulate helps to clarify the results of previous work.

21 citations


01 Nov 1973
TL;DR: In this paper, the results from testing of a 0.3 scale model center duct inlet (S duct) for the Pratt and Whitney Aircraft JT8D-100 engines are presented.
Abstract: The results from testing of a 0.3 scale model center duct inlet (S duct) for the Pratt and Whitney Aircraft JT8D-100 engines are presented. The objective of this test was to demonstrate that the required airflow of the JT8D-100 engine (480 lb/sec as compared to 334 lb/sec for JT8D-15) can be achieved with minimum modifications to the existing 727 airplane structure at acceptable levels of total pressure recovery and distortion. Steady-state pressure recovery, steady-state pressure distortion, and dynamic pressure measurements were taken at the engine face station. Surface static pressure measurements were taken along the duct. Test results indicated that the required airflow was achieved with acceptable pressure recovery (comparable to the current 727-200 S duct). Inlet inflow angle variation within the 727 airplane operating regime (minus 5 to 5 degrees) had no effect on the inlet performance. Pressure distortion at static and forward speed at takeoff airflow conditions are within P and WA limits for the Phase II duct when equipped with vortex generators. Static crosswind operation between 10 knots and 25 knots appears feasible at full takeoff power.

Journal ArticleDOI
TL;DR: The pyrolysis of trimethylthallium has been studied in a mercury free toluene carrier flow system (452-536 °K, total pressure 6.7-39.3mm, contact time 0.9-5.1m, 5.4-90.2% decomposition) as mentioned in this paper.
Abstract: The pyrolysis of trimethylthallium has been studied in a mercury free toluene carrier flow system (452–536 °K, total pressure 6.7–39.3 mm, contact time 0.9–5.1 s, 5.4–90.2% decomposition). In a ves...

01 Jun 1973
TL;DR: A mixed compression axisymmetric inlet model with a capture diameter of 50 cm was tested at Mach numbers ranging from 0.8 to 2.65 at 0 deg angle of attack and a constant total pressure of approximately 1 atm as mentioned in this paper.
Abstract: A mixed compression axisymmetric inlet model with a capture diameter of 50 cm was tested at Mach numbers ranging from 0.8 to 2.65 at 0 deg angle of attack and a constant total pressure of approximately 1 atm. Analytical methods accounting for the effects of both viscous and inviscid flows and incorporating empirical bleed discharge coefficients were used in the procedure for designing the inlet contours and the bleed system. Experimental results are compared with analytic predictions and are also compared with results from earlier tests of an inlet with the same internal contours but with a bleed system developed by cut and try methods in the wind tunnel. With the bleed configuration predicted by the design procedure, maximum total pressure recovery at the engine face at the design Mach number of 2.65 was 93 percent, with a total pressure distortion less than 10 percent. Corresponding bleed mass flow was approximately 7.5 percent, which was about 1.3 percent less than predicted. At lower supersonic Mach numbers, pressure recovery and bleed were generally lower and distortion generally higher.

Journal ArticleDOI
TL;DR: In this paper, the authors used a shock tube in which both pure polymer and propellant specimens, mounted on the end wall, are suddenly exposed to a hot stagnant gas at about 1800 °K and 47 atm.
Abstract: Experiments were performed using a shock tube in which both pure polymer and propellant specimens, mounted on the end wall, are suddenly exposed to a hot stagnant gas at about 1800 °K and 47 atm. The test gas consists of oxygen/nitrogen mixtures in which the oxygen mole fraction is varied from 0.18 to 1.00. The resultant ignition delay is observed to increase sharply as the mole fraction of oxygen is reduced and typical ignitability limits are 0.2 ˜ 0.3 mole fraction or 10 ˜ 15 atm oxygen partial pressure. Ignition delay time is found to be sensitive to total pressure as well as partial pressure. The effect of imbedded oxidizer is found to be significant when the ambient oxygen mole fraction is below 0.5 mole fraction. The theoretical ignition delay predictions of the gas phase and heterogeneous theories are shown to be too close for the experimental data to distinguish between them. A simple flat-surface stagnant exposure (a one-dimensional model) is found to be inadequate to resolve the questio...

01 Jun 1973
TL;DR: In this paper, the aerodynamic and acoustic performance of a translating grid choked-flow inlet was determined in a low-speed wind tunnel at free-stream velocities of 24, 32, and 45 m/sec and incidence angles of 0, 10, 20, 30, 35, 40, 45, and 50 deg.
Abstract: The aerodynamic and acoustic performance of a translating grid choked-flow inlet was determined in a low-speed wind tunnel at free-stream velocities of 24, 32, and 45 m/sec and incidence angles of 0, 10, 20, 30, 35, 40, 45, and 50 deg. The inlet was sized to fit a 13.97- centimeter-diameter fan with a design weight flow of 2.49 kg/sec. Measurements were made to determine inlet total pressure recovery, flow distortion, and sound pressure level for both choked and unchoked geometries over a range of inlet weight flows. For the unchoked geometry, inlet total pressure recovery ranged from 0.983 to 0.989 at incidence angles less than 40 deg. At 40 deg incidence angle, inlet cowl separation was encountered which resulted in lower values of pressure recovery and higher levels of fan broadband noise. For the choked geometry, increasing total pressure losses occurred with increasing inlet weight flow that prevented the inlet from reaching full choked conditions with the particular fan used. These losses were attributed to the high Mach number drag rise characteristics of airfoil grid. At maximum attainable inlet weight flow, the total pressure recovery at static conditions was 0.935. The fan blade passing frequency and other fan generated pure tones were eliminated from the noise spectrum, but the broadband level was increased.

Journal ArticleDOI
TL;DR: Experimental data were taken for both nitrogenhelium and propane-helium systems counterdiffusing through a plug of pelleted Graphon as discussed by the authors, and the experimental pressure range was 1-20 atm for the nitrogen−helium, and 1-8 atm was for the propane−Helium system; the temperature range was 299-408°K.
Abstract: Experimental data were taken for both nitrogen‐helium and propane‐helium systems counterdiffusing through a plug of pelleted Graphon. The experimental pressure range was 1–20 atm for the nitrogen‐helium and 1–8 atm for the propane‐helium system; the temperature range was 299–408°K. The temperature and total pressure gradients were zero in the individual experiments (Wicke‐Kallenbach experiments). Because of the uniform nature of the Graphon surface, significant surface transport of the heavier vapor occurred in all experiments. In neither system was the helium diffusion behavior predictable by the dusty‐gas diffusion equation, as it should have been if the gas‐phase diffusion were unaffected by the moving adsorbed phase. The observed helium flux in the helium‐propane experiments also averaged about 20% lower than predicted from the fluxes in the helium‐nitrogen system. The first of these observations indicates that the presence of a mobile adsorbed phase significantly affects the diffusion behavior of the...

Journal ArticleDOI
01 Aug 1973
TL;DR: In this article, the sparking potentials of dry air, humid air and water vapour between a pair of concentric sphere-hemisphere electrodes are measured, for both voltage polarities of the inner electrode, over a wide range of gas pressures.
Abstract: The sparking potentials of dry air, humid air and water vapour between a pair of concentric sphere-hemisphere electrodes are measured, for both voltage polarities of the inner electrode, over a wide range of gas pressures. In dry air, the measurements are conducted over nearly five orders of magnitude of gas pressure. In dry air and for gas pressure >100 torr, corona is observed to precede the breakdown of the gap when the inner sphere is made negative. On the other hand, the corona inception and the breakdown of the gap occurs at the same potential for the positive polarity of the inner electrode. The total secondary ionisation coefficient in dry air is evaluated from the measured sparking potential, and found to depend on the electrode polarity. The influence of the partial-water-vapour pressure on the sparking potential of air is measured. Practical mixtures of air and partial water vapour are employed. It is observed that the addition of water vapour increases the sparking potential for both the negative and the positive voltage polarities of the inner electrode. The relative increase in the sparking voltage depends on both the partial-water-vapour pressure and the total pressure of the mixture. The sparking potential of water vapour is found to be higher than that of dry air for the same gas pressure.

31 Mar 1973
TL;DR: In this article, the effect of steady state circumferential total pressure distortion on the loss in compressor stall pressure ratio has been established by analytical techniques, and a time constant, directly related to the compressor rotor chord, was found to be significant, indicating compressor sensitivity to this type of distortion is directly dependent on the rotor chord.
Abstract: The effect of steady state circumferential total pressure distortion on the loss in compressor stall pressure ratio has been established by analytical techniques. Full scale engine and compressor/fan component test data were used to provide direct evaluation of the analysis. Specifically, since a circumferential total pressure distortion in an inlet system will result in unsteady flow in the coordinate system of the rotor blades, analysis of this type distortion must be performed from an unsteady aerodynamic point of view. By application of the fundamental aerothermodynamic laws to the inlet/compressor system, parameters important in the design of such a system for compatible operation have been identified. A time constant, directly related to the compressor rotor chord, was found to be significant, indicating compressor sensitivity to circumferential distortion is directly dependent on the rotor chord.

Journal ArticleDOI
TL;DR: In this paper, the supersaturation in a diffusion chamber is computed under various values of the temperature of the vapor source and the total pressure in the chamber, and a comparison is made between the results of the present theory and those of recent experiments.
Abstract: Thermodynamic characteristics in a diffusion chamber are investigated theoretically. A metallic gas evaporated at the center of a chamber is assumed to diffuse through an inert gas without condensation until it arrives at the walls. The supersaturation in the chamber is computed under various values of the temperature of the vapor source and the total pressure in the chamber. Under the assumption that the supersaturation determines the size of the metallic fine particles comparison is made between the results of the present theory and those of recent experiments.

Patent
03 May 1973
TL;DR: In this article, a speed sensitive device is used to control the operation of an aircraft escape system and to improve its performance at lower speed conditions, where the exterior of a bellows is exposed to atmospheric pressure and the inside of this or another bellows connected to the total pressure of the airstream.
Abstract: A speed sensitive device to control the operation of an aircraft escape system and to improve its performance at lower speed conditions. The exterior of a bellows is exposed to atmospheric pressure and the inside of this or another bellows connected thereto is exposed to the total pressure of the airstream. The firing mechanism will not release until a combination of predetermined values of atmospheric pressure and dynamic pressure is present.

Journal ArticleDOI
TL;DR: In this paper, the response characteristics of high sensitivity piezoelectric pressure transducers suitable for use in the plasma flow induced by megawatt-level electric discharges in low density (less than 1 Torr) gases are described.
Abstract: The response characteristics of high sensitivity piezoelectric pressure transducers suitable for use in the plasma flow induced by megawatt-level electric discharges in low density (less than 1 Torr) gases are described. The uniquely designed probe records the initial impingement of a large magnitude total pressure pulse, followed by the flow of primary interest with order-of-magnitude smaller signals. Effects relating to probe and support accelerations, blast shielding and probe heating are evaluated and accounted for in a probe system with a sensitivity of 40 V/atm.

Journal ArticleDOI
Abstract: The saturation solubility of O2+ CH4, O2+ N2 and N2+ CH4 mixtures in water at 25.00°C and 1 atm total pressure are reported at O2 partial pressures of 0.25, 0.5 and 0.75 atm. The solubility of oxygen at a partial pressure of 0.5 atm in the presence of 0.5 atm pressure of helium, of ethane and of krypton are also reported. In all case the saturation solubility of each gas is reduced below the expected Henry's Law value. Current theories for the solubility of gases in water are discussed.

Journal ArticleDOI
TL;DR: Optical gain was detected in the CO X1 -Sigma+ infrared transitions P_{9-8}(12) and P_{8-7} (12) in a 4.6 cm-long free-burning C 2 H 2 -O 2 flame as discussed by the authors.
Abstract: Optical gain was detected in the CO X1 \Sigma+ infrared transitions P_{9-8}(12) and P_{8-7}(12) in a 4.6-cm-long free-burning C 2 H 2 -O 2 flame. At a total pressure of 11-torr gain (or loss) on the P_{9-8}(12) , transition was measured in the preflame, visible flame, and postflame zones of fuel-lean flames.

Journal ArticleDOI
TL;DR: The transition from laminar to turbulent flow alters the relation between catheter measured kinetic energy and kinetic energy calculated by electromagnetically measured flow and results in serious consequences for calculation and interpretation of pulmonary vascular resistance and distensibility of the pulmonary vascular bed.
Abstract: In measuring pulmonary arterial pressure with special catheters in 19 dogs, anesthetized with morphine-urethane, mean pressure differences of 2.2±0.7 (\(\bar x\)±sx) mmHg (=9% of lateral pressure) were obtained between lateral pressure and total pressure at normal flow rates, and of 9.1±2.7 mmHg (=19% of lateral presure) at maximal flow rates. The transition from laminar to turbulent flow alters the relation between catheter measured kinetic energy and kinetic energy calculated by electromagnetically measured flow. There was, howver, no significant difference between lateral pressure and downstream pressure for\(\bar V\) Vk. This is incompatible withBurton's statement to the effect that downstream pressure is significantly lower than lateral pressure, and that this fact results in serious consequences for calculation and interpretation of pulmonary vascular resistance and distensibility of the pulmonary vascular bed. In experiments on models, local turbulences at the catheter opening pointing downstream could be demonstrated and are believed to cause this phenomenon.

01 Dec 1973
TL;DR: In this article, the complete expression of the interaction force between a gas and solid particles at low Reynolds number flow was obtained from both experimental data and theoretical results of the two-phase flow.
Abstract: From both experimental data and theoretical results of the two-phase flow, the complete expression of the interaction force between a gas and solid particles at low Reynolds number flow is obtained. The interaction force contains two terms: one is proportional to the difference between the velocities of the gas and the solid particle with a coefficient as a function of volume fraction Z and the other is proportional to the product of the total pressure of the mixture and the gradient of solid volume fraction. The second term is new. When Z tends to 0, the completion expression of interaction force reduces to the well-known Stokes formula.

Patent
27 Feb 1973
TL;DR: In this paper, an afterburner is used in the engine to determine the gross thrust of a jet engine by measuring various internal pressures, including measurement of total pressure at the nozzle entrance.
Abstract: Apparatus is known for determining gross thrust in jet engines by measuring various internal pressures, including measurement of total pressure at the nozzle entrance by means of an immersed probe. The immersed probe has a very short life when an afterburner is used in the engine. The apparatus for the invention is able to determine total pressure at the nozzle entrance, without an immersed probe, from the total pressure in the diffuser and the static pressure at the nozzle entrance. Another embodiment makes use of an additional static pressure in the flame-holder region. Also, the invention is for determining the gross thrust of an engine and it distinguishes between an engine with a nozzle operating in a choked condition and an unchoked condition.

Patent
27 Sep 1973
TL;DR: An air distribution system for supplying conditioned air to at least one zone to be conditioned and comprising a supply duct connected with a diffuser discharging to the conditioned zone is described in this article.
Abstract: An air distribution system for supplying conditioned air to at least one zone to be conditioned and comprising a supply duct connected with a diffuser discharging to the conditioned zone. A modulating valve is provided with a bellows actuator and a control for the actuator is of the fluidic type with power for the actuator and control supplied from a total pressure pick-up in the duct. A duct static or differential pressure signal is fed to the fluidic control together with a pressure set-point and a zone temperature signal. Zone temperature may be measured at the diffuser with a total duct pressure powered aspirator drawing air over a thermostat or a zone located thermostat may be provided. A warm up override is optional. The fluidics comprise a multistage proportional amplifier and a diaphragm amplifier controlling an orifice in a total duct pressure conduit. A venturi in the conduit has its throat section connected with the bellows actuator selectively to pressurize and draw air therefrom whereby to adjust valve position.

Journal ArticleDOI
TL;DR: In this paper, a constant lead flux of 4.5×1014 cm−2 sec−1 was used to investigate the sticking coefficient for a system with a total pressure range of 10−6−10−5, where the partial pressure of water was restricted to less than 1×10−8
Abstract: Experiments have been conducted at a total pressure of 10−9−10−5 Torr while the partial pressure of water was varied from 10−10 to 10−6 Torr. A constant lead flux of 4.5×1014 atoms cm−2 sec−1 was utilized. Results indicated that a rapid decrease in the initial sticking coefficient reached an asymptote of approximately 0.6 as the partial pressure of the residual water vapor was increased. Also, the sticking coefficient did not approach unity as deposition continued but remained essentially constant. Competitive reactions between the lead and the water molecules with the surface are proposed as an explanation of this latter phenomenon. The sticking coefficient for this system can equal unity in a total pressure range of 10−6−10−5 Torr if the partial pressure of water is restricted to less than 1×10−8 Torr.

Patent
28 Aug 1973
TL;DR: An angle of attack indictor for use as a cock pit instrument including movable elements which respond to the differences in pressure at selected points on the aircraft is described in this paper.
Abstract: An angle of attack indictor for use as a cock pit instrument including movable elements which respond to the differences in pressure at selected points on the aircraft. The pressure points include total pressure sensed by the aircraft pitot tube (po), atmospheric pressure sensed at aircraft static pressure port (p ), and pressure sensed from at least one port on wing surface (p). The difference of one pair of pressures is divided by the difference of a second pair of pressures to obtain the pressure coefficient which is a direct indication of the angle-of-attack of the aircraft.