Showing papers on "Total pressure published in 1974"
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TL;DR: In this paper, the authors used published σ-depth profiles and assuming olivine as the major phase in the earth's upper mantle with ƒ o 2 = 10 −6 −10 −3 bar, temperatures of the upper mantle were calculated as a function of depth.
Abstract: Electrical conductivity σ in the [100] direction has been determined for the Red Sea olivine (Fo 91) to 1440°C and 8 kbar in argon. No systematic variation of σ with pressure was observed. The effect of an 8-kbar variation in pressure over the 1270°–1440°C range is equivalent to a temperature uncertainty of ±5°C. We have also determined σ on the same sample up to 1660°C with controlled oxygen fugacity ƒo2 at 1 bar of total pressure. By using published σ-depth profiles and assuming olivine as the major phase in the earth's upper mantle with ƒ o 2 = 10 −6 -10 −3 bar, temperatures of the upper mantle are calculated as a function of depth. The temperature uncertainty due to possible pressure effects is 2–5 times smaller than that resulting from the ambiguity in published σ-depth profiles.
163 citations
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TL;DR: In this paper, a movable bellows-cup mechanism was used to encase the catalysts in a small volume for high pressure experiments and the cyclopropane hydrogenolysis was investigated at 1 atm on a platinum stepped single crystal (Pt(s)-(6(111) x (100)).
102 citations
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TL;DR: In this paper, a pulsed chemical laser operating on the reaction between hydrogen and fluorine at pressures above the second explosion limit is described, which corresponds to a chemical efficiency of 4% and an over-all electrical efficiency of 1.3% for the particular photolysis geometry employed.
Abstract: Experiments are described on a pulsed chemical laser operating on the reaction between hydrogen and fluorine at pressures above the second explosion limit. A laser energy density of 80 J/liter‐atm is obtained for a mixture of 0.1 F2/0.1 H2/0.8 He mole fraction at 1.1 atm total pressure. This performance corresponds to a chemical efficiency of 4% and an over‐all electrical efficiency of 1.3% for the particular photolysis geometry employed. Various diagnostic experiments are developed to measure the initial fraction of F2 dissociated by the photolysis, the temporal extent of the over‐all reaction, and measurements of medium homogeneity. These data together with measurements of over‐all laser performance are compared with calculations from a comprehensive theoretical model which includes the photolysis process, chemical kinetic reactions, vibrational energy transfer processes, and stimulated emission. The major features of this laser appear to be understood and described by the existing kinetic rate data. Ho...
40 citations
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TL;DR: In this paper, a number of models were tested at subsonic Mach numbers through a range of unseparated, partially separated, and totally separated flow, and static pressure taps were used to determine the surface pressure distribution in the separated region.
Abstract: Separated flow data for axisymmetric afterbodies are presented. A number of models were tested at subsonic Mach numbers through a range of unseparated, partially separated, and totally separated flow. The separation and reattachment locations on the afterbody were determined by oil flow visualization techniques, and static pressure taps were used to determine the surface pressure distribution in the separated region. The data systematically show the effect of shape, Mach number, total pressure and approach boundary-layer thickness upon the onset and extent of flow separation over afterbody models. Existing separation criteria are compared to the data; and an engineering model is proposed for use in predicting the effects of the separated region upon afterbody pressure distribution.
21 citations
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TL;DR: In this article, the authors obtained a maximum pulse energy of 50 J with peak output power of 50 MW and an electrical efficiency of 6% with a 4195 cm3 active volume, a total pressure of 240 Torr, and gas component ratios SF6:H2:F2 of 1.33:1.0.
Abstract: Pulsed HF and DF chemical lasing has been observed in SF6:F2:H2 and SF6:F2:D2 mixtures, respectively, using an electron beam to initiate the laser reactions. Maximum pulse energies of 50 J with peak output power of 50 MW and an electrical efficiency of 6% were obtained with a 4195‐cm3 active volume, a total pressure of 240 Torr, and gas component ratios SF6:H2:F2 of 1.33:1.0:1.0. For an active volume of 236 cm3, a total pressure of 420 Torr, and SF6:H2:F2 equal to 1.5:1.0:1.0, 11 J energy was obtained corresponding to an energy density of 80 J/l atm. For DF lasing from mixtures of SF6, D2, and F2, the output energy is a factor of 2–3 smaller than for HF lasing from mixtures of SF6, H2, and F2 with the same initial conditions.
17 citations
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01 May 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: The high temperature oxidation of tungsten wires in free convection was measured in water vapor-argon atmospheres in the temperature range between 2450 and 3000°K and in the H2O partial pressure range between 339 × 10-5 and 182 × 10 -4 atm at 0789 atm total pressure as discussed by the authors.
Abstract: The high temperature oxidation of tungsten wires in free convection was measured in water vapor-argon atmospheres in the temperature range between 2450 and 3000°K and in the H2O partial pressure range between 339 × 10-5 and 182 × 10-4 atm at 0789 atm total pressure The rate of the reaction generally decreases with increasing temperature at constant bulk water vapor pressure This dependence is similar to that previously measured in O2-argon and CO2-argon atmosphere The overall oxidation reaction is gas transport controlled as demonstrated by supplemental measurements at 0395 atm total pressure A volatile oxide counter diffusion model, which has been previously proposed to explain the oxidation in O2-and CO2-argon, is in good agreement with H2O-argon experiments A comparison of the present results with the previous experiments shows that the model is in agreement with the relative magnitude of the oxidation rates measured in the three oxidizing atmospheres
16 citations
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TL;DR: In this article, additional inhibitors for the conversion of NO to NO2 in C3H6-NO-02 irradiated mixtures have been tested at 25°C, and the NO2 pressure was monitored photometrically.
Abstract: Additional inhibitors for the conversion of NO to NO2 in C3H6—NO—02 irradiated mixtures have been tested at 25°C. These mixtures initially contained 16 mTorr C3H6, 8 mTorr NO, 0.012 mTorr NO2, additive, and enough O2 to bring the total pressure to 100 Torr. The NO2 pressure was monitored photometrically. In the absence of additive, the NO2 pressure first increases with irradiation time reaching a maximum conversion at about 15 minutes. As the irradiation time increases beyond 15 min, the NO2 pressure drops. Before adding the inhibitors, runs were done with 10 Torr of CO added, and in these runs the conversion was speeded so that the maximum in NO2 pressure occurred at 10 min. This enhancement in conversion rate is considered to be diagnostic for the presence of HO radicals. Next 10-min irradiations were done with various amounts of hexafluorobenzene (C6F6), nitrobenzene (C6H5NO2), or naphtha lene (C10H8) added. The NO2 pressure was reduced to one-half its value in the absence of inhibitor with 270 mTorr C...
16 citations
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TL;DR: Oxygen partial pressures in atmospheric-pressure quench furnaces were found to vary by as much as 0·5 in log fo2 when changes were made in gas flow rate and direction suggesting that careful analysis of the gas mixture supplied to a furnace is not a guarantee of the oxygen pressure that a sample in the furnace will attain this paper.
Abstract: Oxygen partial pressures in atmospheric-pressure quench furnaces were found to vary by as much as 0·5 in log fo2 when changes were made in gas flow rate and direction suggesting that careful analysis of the gas mixture supplied to a furnace is not a guarantee of the oxygen pressure that a sample in the furnace will attain. The use of magnesiowustite compositions, with variable oxygen contents, as indicators of oxygen pressure is described.
15 citations
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TL;DR: In this article, the lifetime of Hg(63P0) in a gaseous mixture of Ar and N2 with quenching molecules (Q) was measured by monitoring the decay of the Hg (63P 0) concentration following the excitation by pulsed 253.7 nm radiation, which can be attributed to the deactivation by impurities involved in the gas and that by collision on the wall of the reaction cell.
Abstract: The lifetime of Hg(63P0) in a gaseous mixture of Ar and N2 with quenching molecules (Q) was measured by monitoring the decay of the Hg(63P0) concentration following the excitation of Hg by pulsed 253.7 nm radiation. The lifetime in the absence of Q was reduced with the increase in the N2 pressure, being inversely proportional to the total pressure. This can be attributed to the deactivation by impurities involved in the gas and that by collision on the wall of the reaction cell. Deactivation due to impurities is dominant at a total pressure higher than 50 Torr. With quenchers in the mixture, the lifetime measurement gave the quenching cross-section of Hg(63P0). In addition, the measurement of the stationary concentration of Hg(63P0) made it possible to determine the rate for each of the processes 63P1→63P0 and 63P1→61S0. Based on the observed ratio, α=σ2(63P1→61S0)/σ2(63P1→61S0), quenching molecules are classified into three groups. The first group consists of N2O, O2, C2H4, C3H6, and C2H2 with α1.2 These...
13 citations
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TL;DR: In this paper, the authors used the method proposed by Alpert and Buritz, with a slight modification, for estimates of the tungsten evaporation limit; i.e., a second filament served as an auxiliary source of evaporated tungstein atoms, and three gauges were tested, one gauge with a buried collector and two modulated Bayard-Alpert gauges.
Abstract: Comparative measurements of pressures in the low 10−12-Torr range with hot-filament total and partial pressure gauges have shown discrepancies which can be partly explained by the influence of tungsten vapor from the hot filament on the total pressure gauge readings (tungsten evaporation limit). The method proposed by Alpert and Buritz, with a slight modification, was used for estimates of the tungsten evaporation limit; i.e., a second filament served as an auxiliary source of evaporated tungsten atoms. Three gauges were tested, one gauge with a buried collector and two modulated Bayard-Alpert gauges. The experiments showed that the tungsten evaporation limits of all three gauges fell in the range (1–2)×10−12 Torr (nitrogen equivalent pressure) with an electron emission of 10 mA. Provided the variation of the gauge sensitivity with the emission is known, it is recommended to operate at reduced emission (e.g., 4 mA), at which level the tungsten limit is substantially lower. Low-work-function emitters, as a...
12 citations
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06 Sep 1974
TL;DR: In this paper, the authors propose a flexible and rigid tube for reading the static pressure and a flexible tube for measuring the velocity and pressure changes in a walk-in duct, respectively, without drilling or cutting access holes in the duct wall.
Abstract: For use in measuring air velocity and pressure changes in a duct, a gauging system comprising a gauge including a vertically extending transparent tube within which a ball moves to a position corresponding to the pressure in the tube above and below the ball, a velocity scale and a pressure scale extending alongside the tube and increasing from their lower end to their upper end, a vertically extending transparent shell enclosing the tube, and one or more rigid tubes for connecting the lower end of the gauge tube to the interior of the duct to read total pressure or static pressure and a flexible tube for connecting the upper end of the shell to the interior of the duct to read static pressure. The rigid tube or tubes provide a distal end portion with an open end arranged to be pointed upstream or opposite to the direction of flow of air through the duct to read total pressure including velocity pressure and static pressure while the flexible tube provides a distal end portion with an open end and arranged to read the static pressure. The static pressure, therefore, pushes downwardly upon the ball while the total pressure pushes upwardly on the ball such that the static pressure is subtracted from the total pressure leaving velocity pressure which corresponds to velocity. The gauging system can simply be carried into a walk-in duct to read the air velocity therein without drilling or cutting access holes in the duct wall. The gauging system can be used to read pressure drop or increase across an item such as a coil or fan in a duct.
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TL;DR: In this paper, a 1.1 W output was achieved from a compact (14 cm discharge length, 2mm bore diameter tube) sealed-off CO waveguide laser operating in the HE11 mode.
Abstract: cw output of 1.1 W was attained from a compact (14‐cm discharge length, 2‐mm bore diameter tube) sealed‐off CO waveguide laser operating in the HE11 mode. The BeO laser tube, cooled to 210 °K, was operated at the 1‐W level for more than 4 h without output degradation and with a 5.7% efficiency. A mixture of CO:He:Xe:N2 in the ratio of 1:8:1:1, at a total pressure of 80 Torr, was found to be optimum, confirming the scaling or similarity rule of the product of optimum pressure and tube diameter for CO at this temperature. The output spectrum consisted of about 10 lines, between 5.20 and 5.65 μ. Laser operation without N2 (1:8:1:0) was also observed. Black particles found in the tube were x‐ray identified as Ni plus NiO, indicating sputtering from the Ni cathode.
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18 Mar 1974
TL;DR: In this paper, the authors proposed a method for determining the total pressure in the afterburner of an afterburning jet engine without using an immersed probe downstream of the after-burner.
Abstract: Apparatus is known for determining the total pressure in the nozzle of an afterburning jet engine without using an immersed probe downstream of the afterburner. This known apparatus uses tailpipe pressures as the only variables used to determine nozzle total pressure, however it is based on an engine having a cylindrical afterburner tailpipe, having no cooling air introduced upstream of the nozzle entrance, and it neglects frictional factors in the working fluid. The present invention takes into account in the determination of nozzle total pressure, the following factors: the tailpipe liner need not be cylindrical, cooling air may be added, and frictional effects are considered. The apparatus determines nozzle total pressure in an afterburning engine whether or not the afterburner is operating and without requiring an input to show whether or not the afterburner is operating. A further embodiment determines the engine gross thrust using nozzle total pressure as one parameter in the determination.
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IBM1
TL;DR: In this article, a method for the production and deposition of epitaxial films from volatile compounds of gallium, boron and aluminum, and mixtures thereof, and the compounds of phosphorous and arsenic, is disclosed comprising controlling the total vapor pressure of the gaseous arsenic and phosphorous reactants between limits to produce an ultimate light emitting diode having improved external quantum efficiency.
Abstract: In the method for the production and deposition of epitaxial films from volatile compounds of gallium, boron and aluminum, and mixtures thereof, and the compounds of phosphorous and arsenic, the improvement is disclosed comprising controlling the total vapor pressure of the gaseous arsenic and phosphorous reactants between limits to produce an ultimate light emitting diode having improved external quantum efficiency. The ratio of the partial pressures of the group V hydrides to each other, for example, the ratio of the arsine partial pressure to the phosphine is fixed, or determined by the composition desired in the solid, while the ratio of the group III halide partial pressure to the total group V hydride pressure can be varied without changing, or modifying, the composition of the final solid. The prior art teaches that variations in this ratio lead to variations in the quality of the resulting material. Applicants have discovered that the quality of the resulting semiconductor material, as measured by the quantum efficiency of a light emitting diode made from it is more sensitive to the total pressure of the reacting gasses (PHCl + PAsH + PPH ) than it is to the ratio (PHCl/ (PAsH + PPH ), the ratio between the group III halides vapor pressure to the group V hydride vapor pressure.
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01 Jan 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the authors investigated the oxidation kinetics of tungsten wires in natural convection in CO2-argon mixtures in the temperature range between 2450 and 3000K and the CO2 partial pressure range between 2.13 × 10-5 to 1.789 atm total pressure.
Abstract: The oxidation kinetics of tungsten wires in natural convection has been investigated in CO2-argon mixtures in the temperature range between 2450 and 3000K and the CO2 partial pressure range between 2.13 × 10-5 to 1.28 × 10-4 atm at 0.789 atm total pressure. The rate generally decreases with increasing temperature at constant bulk CO2 pressure with a magnitude ranging between 0.5 to 5 × 10-6 g/cm2 s. The oxidation reaction is gas transport controlled as demonstrated by supplemental measurements at 0.395 atm total pressure. A volatile oxide counter diffusion model, which has been previously proposed to explain the oxidation kinetics of tungsten wires in O2-argon mixtures, is in reasonable agreement with the data.
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TL;DR: In this paper, it was shown that pyrolysis of ACl to A + Cl is important, but thermal decomposition of the deactivated ACl radical is not.
Abstract: Propane has been photochlorinated in competition with cis- and trans-dichloroethylene (c-DCE and t-DCE), 1,1-dichloroethylene (1,1-DCE), trichloroethylene (TrCE) and tetrachloroethylene (TCE) at temperatures between 300 and 350 K and pressures up to 200 Torr (1 Torr = 1.33 × 102 N m–2).The balance of decomposition to collisional stabilisation of excited chloroalkyl radicals, ACl* formed in reaction (2), A + Cl [graphic ommitted] ACl*, is important in the chlorination of c–DCE, t-DCE and TrCE, but thermal decomposition of the deactivated ACl radical is not. With TCE the opposite occurs, pyrolysis of ACl to A + Cl is important but decomposition of ACl* before deactivation is not.At 350 K, k2 for c-DCE and t-DCE are identical at 3.5 × 1010 dm3 mol–1 s–1. The fraction of C2H2Cl* decomposing to c–DCE, determined using radiochlorine, is 0.67 and is also independent of the precursor. Assuming unit collision efficiency for deactivation of ACl* the following high pressure values for ka are obtained, ka(c-DCE)= 1.6 × 109 s–1; ka(t-DCE)= 3.0 × 109 s–1. Both values are pressure dependent falling with total pressure in good agreement with predictions from RRKM theory.Attempts to study 1,1-DCE were unsuccessful due to a rapid heterogeneous reaction which was apparently initiated photochemically.For TrCE, ka was determined using radiochlorine to be 4 × 108 s–1 and k2 to be 3 × 1010 dm3 mol–1 s–1. Pressure dependence of ka over a limited pressure range agreed with RRKM theory.The rate of chlorination of TCE relative to propane was independent of total pressure when varied by adding inert gas (SF6) but was strongly dependent upon chlorine pressure especially at higher temperatures. We deduce that ka < 2 × 107 s–1 and k2= 2 × 1010 dm3 mol–1 s–1. The rate constant k4 for pyrolysis of C2Cl5 was obtained from the chlorine dependence as, log10(k4/s–1)=(13.47 ± 0.50)–(15 500 ± 700)K/4.576T, in reasonable agreement with previous work.
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TL;DR: In this article, up to 5 pulses/sec repetitive operation with an electron-beam-initiated SF6-H2 chemical laser was achieved with an active volume of 244 m1 and a total pressure of 600 Torr.
Abstract: Up to 5 pulses/sec repetitive operation has been achieved with an electron‐beam‐initiated SF6–H2 chemical laser. Maximum laser energies of 250 mJ/pulse have been obtained from an active volume of 244 m1 and a total pressure of 600 Torr. Lasing was also observed from SF6–D2 mixtures with peak energies one‐half of those from SF6–H2.
01 Feb 1974
TL;DR: In this article, the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions was evaluated using a series of tests.
Abstract: Tests were conducted to determine the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions. The test gas simulates air in that it duplicates the total temperature, total pressure, and the volume fraction of oxygen of air at flight conditions. The main objective of the tests was to determine the performance of the burner as a function of the effective exhaust port area. The conclusions were: (1) pressure oscillations of the chugging type were reduced in amplitude to plus or minus 2 percent of the mean pressure level by proper sizing of hydrogen, oxygen, and air injector flow areas; (2) combustion efficiency remained essentially constant as the exhaust port area was increased by a factor of 3.4; (3) the mean total temperature determined from integrating the exit radial gas property profiles was within plus or minus 5 percent of the theoretical bulk total temperature; (4) the measured exit total temperature profile had a local peak temperature more than 30 percent greater than the theoretical bulk total temperature; and (5) measured heat transfer to the burner liner was 75 percent of that predicted by theory based on a flat radial temperature profile.
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TL;DR: In this article, a viscous interaction study was performed to investigate the separation phenomena which occur ahead of two-dimensional steps and slot jets in a half-nozzle boundary-layer channel.
Abstract: The objective of this viscous interaction study was to investigate the separation phenomena which occur ahead of two-dimensional steps and slot jets. This investigation was restricted to the case where the height, /?, of the step or jet was less than the boundary-layer thickness, <5. The boundary layer, itself, was turbulent and adiabatic. The independent test variables selected were Red and h/6. The tests were performed in a two-dimensional, Mach 4.9 half-nozzle boundary-layer channel. Two glass-ported side pla\es were used to split off the thick sidewall boundary layers. The significance of two parameters, i.e., the Reynolds number and h/d, was revealed in the study; the degree of influence of either parameter decreased as its value increased. Three useful geometric scaling parameters were defined with the first scaling the initial steep pressure rise region and the second scaling the separation region of the total pressure profile. Use of these two distances permitted the development of a universal pressure profile. The third distance scaled the physical system by defining the standoff position of the separation shock in the freestream.
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TL;DR: In this article, the vibrational contribution to the total pressure, the volume variation of the Gruneisen parameter, and the temperature variation of second order elastic constants are calculated making the approximation of replacing the normal mode frequency by the square root of the second moment mu 2.
Abstract: The equations are calculated using the model pseudopotential of Wallace. In calculating the vibrational contribution to the total pressure, the volume variation of the Gruneisen parameter is taken into account. The calculated isotherms at 300K and 100K are compared with the experimental measurements of other researchers. The agreement between theory and experiment at 300K is extremely good up to a pressure of 45 kilobars. The agreement at 100K is fairly good up to a pressure of 20 kbar. Using the same potential the temperature variation of the second order elastic constants are calculated making the approximation of replacing the normal mode frequency by the square root of the second moment mu 2. The calculated results indicate that in the case of C11 and C12 the temperature dependence has the right behaviour, whereas C44 almost comes out independent of temperature as against the experiment which shows a rapid decrease.
01 Apr 1974
TL;DR: In this paper, the effect of incidence angle on the aerodynamic performance of an uncooled core turbine rotor blade was investigated experimentally in a two-dimensional cascade, and the results of the investigation include blade-surface velocity distribution and overall performance in terms of weight flow and loss for the range of incidence angles and exit velocity ratios investigated.
Abstract: The effect of incidence angle on the aerodynamic performance of an uncooled core turbine rotor blade was investigated experimentally in a two-dimensional cascade. The cascade test covered a range of incidence angles from minus 15 deg to 15 deg in 5-degree increments and a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95. The principal measurements were blade-surface static pressures and cross-channel surveys of exit total pressure, static pressure, and flow angle. The results of the investigation include blade-surface velocity distribution and overall performance in terms of weight flow and loss for the range of incidence angles and exit velocity ratios investigated. The measured losses are also compared with two common methods of predicting incidence loss.
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TL;DR: In this article, the dependence of the output power of a CO laser on the composition of the working gas mixture cooled by running water was investigated, and it was shown that the most efficient mixture was one of the composition CO:N2:He:O2:Xe = 1:5:24:0.04:1 kept at a total pressure of 20 mm Hg and excited with a current i = 20 mA.
Abstract: An investigation was made of the dependence of the output power of a CO laser on the composition of the working gas mixture cooled by running water. It was established that the most efficient mixture was one of the composition CO:N2:He:O2:Xe = 1:5:24:0.04:1 kept at a total pressure of 20 mm Hg and excited with a current i =20 mA.
01 Jan 1974
TL;DR: The measured effects of a circumferential distortion in inlet total pressure on the fan, low, and high compressor of an afterburning turbofan engine are presented and discussed in this paper.
Abstract: The measured effects of a circumferential distortion in inlet total pressure on the fan, low, and high compressor of an afterburning turbofan engine are presented and discussed. Extensive inner-stage instrumentation, combined with a unique test technique offered an accurate means of measuring the shifts in flow, performance, and stall mechanisms within the compressor. These effects are compared at one speed to the corresponding effects measured with undistorted inlet flow. The results show the rate at which the distorted flow areas were attenuated and rotated, as well as the change in flow velocities that occurred at various points in the compressor. High response pressure traces indicated the location of stalls including the sequence of dynamic events from the onset and propagation of various stall-recovery events, to compressor surge, to the resulting hammershock.
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TL;DR: In this paper, the authors used a manostat to measure the overall rate of reaction over a wide range of reactant pressures and showed that the reaction is zero order for nitrogen and hydrogen at low pressure with a transition at 10−1 torr, as expected for a surface saturated with δ-nitrogen, WsN, at low pressures and formation of η-species, WS2N3H, above 10− 1 torr.
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TL;DR: In this paper, a mixture of CH4, N2, and He gases is used as the flowing gas with a mixing ratio of 1:1:2 by volume, total pressure of 1.6 Torr and gas flowrate of 6∼8 liter Torr/min.
Abstract: Techniques are described which have been found adequate for operating a HCN laser with stable cw action at wavelengths of 337 and 311 μ; the fluctuation of output power is about ±2% without intentional stabilization by retuning for over 10 h. The main features of the design are: (i) a mixture of CH4, N2, and He gases is used as the flowing gas with a mixing ratio of 1:1:2 by volume; total pressure of 1.6 Torr and gas flowrate of 6∼8 liter Torr/min; (ii) the fluctuation of gas pressure is kept within 0.01 Torr; (iii) the cathode is not grounded but negatively charged about 10% of the dc source voltage. Some of these techniques are applicable to other HCN lasers.
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14 Aug 1974
TL;DR: In this paper, the use of variable diaphragm as the sensitive element of a low level pressure sensor as in an aircraft airspeed indicator is described, based on the shape and angle of attack of the aircraft.
Abstract: An angle of attack indicator for use as a cockpit instrument including movable variable-area diaphragms which respond to the differences in pressure at selected points on the aircraft. The pressure points may include the total pressure sensed by the aircraft pitot tube and two other pressures at least one of which varies strongly with the angle of attack. The mechanism divides the difference between total pressure and one of the other two pressures by the difference between the total pressure and the other of the other two pressures obtaining a pressure coefficient which depends only on the shape and angle of attack of the aircraft. The use of the variable diaphragm as the sensitive element of a low level pressure sensor as in an aircraft airspeed indicator is described.
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13 May 1974
TL;DR: In this paper, a magnesium oxide porous target having a high heat resistance, uniform glanularity of background and as good or better performances than potassium chloride porous targets is produced by burning metallic magnesium in a mixed gas of oxygen and an inert gas, to form magnesium oxide smoke and depositing the resulting magnesium oxides smoke on a supporting film, the total pressure of the mixed gas and the partial pressure of oxygen being specifically defined.
Abstract: A magnesium oxide porous target having a high heat resistance, a uniform glanularity of background and as good or better performances than potassium chloride porous targets is produced by burning metallic magnesium in a mixed gas of oxygen and an inert gas, to form magnesium oxide smoke and depositing the resulting magnesium oxide smoke on a supporting film, the total pressure of the mixed gas and the partial pressure of oxygen being specifically defined.
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TL;DR: In this paper, a new method of deriving vapour liquid equilibrium data at constant pressure from isothermal vapour-liquid equilibria was presented and the calculated values using this method were found to be in good agreement with the literature values.
Abstract: Isothermal vapour-liquid equilibrium data was obtained by the total pressure method for the binary system acetone-water at , and , respectively. Barker's approximation method was employed for the calculations of the vapour composition and Wilson parameters. A new method of deriving vapour-liquid equilibrium data at constant pressure from isothermal vapour-liquid equilibria was presented and the calculated values using this method were found to be in good agreement with the literature values.
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01 Jun 1974
TL;DR: In this paper, the effect of interaction between conical diffusers and conical flow in the entry pipe has been investigated, with the most significant gains being with the lowest angle diffuser.
Abstract: Experimental results are presented for the variation of the static pressure rise coefficient Cp, the transformation efficiency η the total pressure loss coefficient CL and the outlet kinetic energy coefficient ɛ2 with the Mach number and the effective throat length for subsonic conical diffusers with total expansion angles of 5°, 12° and 20° and an overall area ratio of 10:1. The junction between the parallel entry pipe and the diffuser cone is sharp and the diffuser inlet conditions are evaluated from measurements on a plane 1°5 diameters upstream of the diffuser's sharp transition. The shock Mach number was varied from 1°05 to 1°25 whilst the diffuser inlet Reynolds number varied between 9°0 × 105 and 1°22 × 106. A comparison of the results with those of diffusers preceded by wholly subsonic flow in the entry pipe shows the beneficial effect of interaction, the most significant gains being with the lowest angle diffuser.
01 Jan 1974
TL;DR: In this article, a supersonic axial-compressor stage was designed for a tip speed of 1600 ft/sec, a stage total pressure ratio of 3.0 and an inlet hub/tip radius ratio of 0.75.
Abstract: : Complete experimental results are presented from tests of a supersonic axial-compressor stage designed for a tip speed of 1600 ft/sec, a stage total pressure ratio of 3.0 and an inlet hub/tip radius ratio of 0.75. At design speed, the compressor passed 70 percent of design flow, achieved a stage total pressure ratio of 2.25, and achieved isentropic efficiencies of 0.74 for the rotor and 0.61 for the stage. This poor performance was attributed to an excessive increase of rotor deviation angle as rotor incidence increased at part speed. A proposed solution to this problem is described.