Showing papers on "Inert gas published in 1982"

Method and means for converting graphite to diamond

Abstract: A host liquid, such as a liquid metal, which is "seeded" with small bubbles of an inert gas, is maintained in a sealed chamber at an ambient temperature of about 100° K. above the melting point of the host liquid, and at a static pressure ranging from 1 to 100 bars. A substance (for example carbon) which is capable of being allotropically transformed from a first form thereof (for example graphite) to a second form (for example diamond), is placed in the host liquid, which is then subjected to a time-varying acoustical pressure applied, for example, by a plurality of solid acoustical horns, which cause at least certain of the bubbles of inert gas to expand and then suddenly to collapse in a cavitation zone located substantially centrally of the chamber. By maintaining the host liquid at a pressure and temperature sufficient to cause the Hugonoit curve of the liquid to intersect a predetermined area of the phase diagram of the substance, the shock waves produced by the collapsing bubbles can be caused to envelop particles of graphite and to instantaneously transform them into diamond particles. The host liquid can be selected from a group consisting of aluminum, tin, gallium, thallium and indium, and alloys thereof; and the substance to be transformed may be selected from the group consisting of carbon, boron nitride and zinc sulphide.

Fluid dynamics of vertical submerged gas jets in liquid metal processing systems

Abstract: High speed cinematography and a pressure trace technique have been used to investigate the fluid dynamics of inert gas jets injected vertically upward into water, molten tin, lead-tin alloy, and iron. Two flow regimes of jet behavior were observed: one in which unstable bubbles were produced at the jet nozzle, and one in which a steady cone of gas emerged from the nozzle and broke up continuously into small bubbles. The transition between bubbling and continuous jet flow was controlled by the mass flow of gas per unit area of the jet and occurred at a flow rate of approximately 40 g/cm2 s in all of the systems studied.

Detection means for the selective detection of gases, based on optical spectroscopy

Abstract: An optical detection system for selectively detecting gases comprises a light source emitting light thermally or mechanically modulated and supplied to a measuring cell. The light source includes an emitter enclosed in an ellipsoid reflector. The ellipsoid reflector can receive measuring gas directly, or is evacuated or filled with an inert gas which does not absorb in the measuring gas absorption range. With measuring gas supplied directly to the reflector, the light emanating from the reflector is supplied to a wide-band detector, combined with a monochromator, e.g. an optical narrow-band filter. With an evacuated or inert gas filled reflector, after traversing a monochromator, the light is irradiated into a photoacoustic detection cell containing the measuring gas. The photoacoustic cell is completely or approximately closed during measurement. Devices, providing the acoustic decoupling in the photoacoustic cell during the measurement and gas exchanges, can include capillaries in the cell wall, liquid cutout devices, mechanical valves or diaphragm pump-valve combinations. Microphone signals processed by a lock-in amplifier operating in a digital off-line manner and controlled by a microprocessor can control the system. The gas scavenging and signal processing of several gas detector units can take place with a single processor unit.

Patterns of interaction of effects of light metabolically inert gases with those of hydrostatic pressure as such--a review.

Abstract: This review of available literature attempts to interpret net effects of metabolically inert light gases (He, H2, and Ne) as the resultant of hydrostatic pressure and intrinsic pharmacological effects associated with exposure to these gases, and to assess the relative importance of each component with respect to a number of biological responses. A common pattern is recognizable for pressure reversal of anesthesia, high pressure convulsions, high pressure bradycardia, and certain characteristics of liposome model systems. Using the method of analysis proposed, these lightest gases can be shown to conform to the pattern of relation of potency to physical properties characteristic of more potent gaseous anesthetics, including N2, N2O, and Xe. The relations between effect produced and partial pressure of the acting gas are approximately linear to total pressures of 100 ATA for anesthesia or pressure reversal of anesthesia and (or to a much smaller extent) for the liposome model systems, but not for high pressure convulsions. As a result of these general factors no single gas can be expected to neutralize the effects of hydrostatic pressure with regard to all of the biological responses tested over any significant pressure range. A series of experiments with single cells and tissue cultures have revealed interactions between high pressure and inert gas that do not conform to the pattern set by the responses mentioned so far. These responses cannot yet be shown to constitute a homogeneous group and may represent at least two subgroups. Responses falling into this second heterogeneous category include cell motility, development of cell abnormalities and lysis, and cell and perhaps virus replication or multiplication. The implication of these results for the formulation of biophysical hypotheses to explain interactions between inert gas and high pressure, for considerations of high pressure effects as a safety hazard, and for the problem of experimental approaches to the study of pressure acclimation are discussed briefly.

Inert gas condensation of metal microclusters

Abstract: Metal microclusters of lead, indium, bismuth and antimony in the size range between 2 to 500 atoms per cluster are generated by inert gas condensation, extracted into vacuum and detected by mass spectrometry. Resolved clusterpeaks are observed up to Pb110, In50, Bi70 and Sb240. Condensation conditions, beam intensities and limitations of the cluster source are discussed.

Pulmonary gas exchange during high-frequency ventilation.

Abstract: Gas exchange was investigated in normal anesthetized dogs during high-frequency, low-tidal volume ventilation (HFV) using the multiple inert gas elimination method. The pattern of inert gas elimination was initially normal during conventional mechanical ventilation. During HFV there was an increase in the difference between the excretion values of acetone and its less soluble neighboring gases, enflurane and ether, but elimination was independent of molecular weight. This pattern was consistent with a major degree of parallel ventilation-perfusion inequality with 49.4 +/- 1.7% of alveolar ventilation being distributed to lung units with VA/Q ratios greater than 20. Additional experiments, however, showed insufficient change in pulmonary blood flow distribution during HFV to account for these apparently poorly perfused lung units. Instead, it was found that the flux from the lung of the most soluble gas, acetone, per unit concentration difference along the airways was approximately twice that for other gases. Experiments using a simple airway model suggested that this enhanced transport of high-solubility gases during HFV is dependent on the wet luminal surface of conducting airways. A reciprocating exchange of gas between the lumen and airway lining layer is proposed as the most likely explanation for these results.

Operation of the J-series thruster using inert gas

Abstract: Electron bombardment ion thrusters using inert gases are candidates for large space systems. The J-Series 30 cm diameter thruster, designed for operation up to 3 k-W with mercury, is at a state of technology readiness. The characteristics of operation with xenon, krypton, and argon propellants in a J-Series thruster with that obtained with mercury are compared. The performance of the discharge chamber, ion optics, and neutralizer and the overall efficiency as functions of input power and specific impulse and thruster lifetime were evaluated. As expected, the discharge chamber performance with inert gases decreased with decreasing atomic mass. Aspects of the J-Series thruster design which would require modification to provide operation at high power with insert gases were identified.

Production of high-molecular weight polylactide

Abstract: PURPOSE: To produce a high-MW (MW≥4,000) polylactide without employing any catalyst, by directly condensing lactic acid by dehydration under a specified condition. CONSTITUTION: Lactic acid (any of L-, D- and racemate) is condensed by dehydration in the absence of any catalyst in an inert gas atmosphere. Lactic acid is placed in a reaction vessel and heated slowly to effect the condensation under a stream of an inert gas (e.g., N 2 ). Then, the reaction temperature is raised slowly and the pressure is lowered slowly and the reaction is brought to completion under a final condition including a temperature of 220W260°C and a pressure of below 10mmHg to obtain a polylactide of a MW≥4,000. This polylactide is useful for use in medical materials. COPYRIGHT: (C)1984,JPO&Japio

Improved ion containment using a ring-cusp ion thruster

Abstract: A 30-centimeter diameter ring-cusp ion thruster is described which operates at inert gas ion beam currents up to about 7 ampere, with significant improvements in discharge chamber performance over conventional divergent-field thrusters. The thruster has strong boundary ring-cusp magnetic fields, a diverging field on the cathode region, and a nearly field-free volume upstream of the ion extraction system. Minimum ion beam production costs of 90 to 100 watts per beam ampere (W/A) were obtained for argon, krypton and xenon. Propellant efficiencies in excess of 0.90 were achieved at 100 to 120 W/A for the three inert gases. The ion beam charge-state was documented with a collimating mass spectrometer probe to allow evaluation of overall thruster efficiencies.

Chemiluminescent sulfur detection apparatus and method

Abstract: In the illustrated and preferred embodiment of this disclosure, a chemiluminescent sulfur detector, both method and apparatus, for detecting bonded sulfur in compounds is disclosed The illustrated and preferred embodiment, being provided with a discrete sample, passes the sample through a first furnace in the presence of a carrier of inert gas and is exposed to a suitable granulated metal oxide, such as copper oxide or vanadium pentoxide, resulting in oxidation of the sulfur compound The sample is then passed through a second furnace comingled with elemental hydrogen, there being a conversion of sulfur oxides to hydrogen sulfide The output of the second furnace is dried The hydrogen sulfide, along with the inert carrier gas, is introduced into a reaction chamber and is mixed with ozone A chemiluminescent reaction occurs in the chamber, and the resulting light emission is measured photoelectrically by either a photomultiplier tube or photodiode The output from the photomultiplier tube is connected to a summing circuit, and the summation represents the measure of sulfur in the specimen The reaction chamber is evacuated through an outlet system so that continuous processing of samples can be achieved

Influence of condensation parameters on the size distribution of metal clusters

Abstract: Microclusters of Pb and Bi, prepared by inert gas condensation, were studied by time of flight mass spectrometry. Cluster size distributions are presented for various metal and gas temperatures inside the condensation chamber. Increasing metal temperature as well as decreasing gas temperature result in a larger mean cluster size. Microparticles can be grown in a helium atmosphere whereas in other gases like Ar, Ne, Kr, N2 and H2 the particles become too large to be detected by the mass spectrometer. The cluster spectra show characteristic distributions, typical for each metal and independent of condensation conditions.

New catalyst components for the polymerization of ethylene and of mixtures thereof with olefins and catalysts obtained therefrom

Abstract: An emulsion or dispersion of a catalyst component in an inert liquid medium or an inert gas phase of a dispersion liquid phase, wherein the catalyst component is: (a) a compound of a transition metal from groups IV to VI which, in the liquid state, is immiscible with an aliphatic hydrocarbon, (b) a composi-tion comprising a compound as defined in (a) which, in the liquid state, is immiscible with an aliphatic hydro-carbon, or (c) a transformation product of a precursor of a compound as defined in (a) and a composition as defined in (b) which, in the liquid state, is immiscible with an aliphatic hydrocarbon. The emulsion or dis-persion is directly useable for the preparation of a coordination catalyst having a controlled morphology and/or a controlled particle size. The coordination catalyst polymerizes ethylene or a mixture thereof with another olefin to a polymer having controlled morphology and/or controlled particle size.

Wafer support system

Abstract: A system for supporting wafers (18) on a gas cushion within the vacuum chamber (12) of a plasma etcher (10). An etchant gas is introduced into the vacuum chamber, and a second gas at a volume flow rate much lower than the volume flow rate of the etchant gas is directed to orifices formed in a wafer-receiving surface of an electrode (16) to define the gas cushion. In accordance with one aspect of the invention, the second gas is an inert gas, and in accordance with another aspect of the invention, the second gas is a reactant gas which is also directed into the vacuum chamber to serve as a reactant gas in conjunction with the first reactant gas.

Process and apparatus for recovering hydrocarbons from inert gas-hydrocarbon vapor mixtures

Abstract: A process and apparatus for recovering hydrocarbons from inert gas-hydrocarbon vapor mixtures wherein the mixture is caused to flow through a bed ( 1 2) of solid adsorbent whereby the hydrocarbons are removed from the mixture and a residue gas stream comprised of substantially hydrocarbon-free inert gas is produced (at 46). A second bed (14) of solid adsorbent having hydrocarbons previously adsorbed thereon is regenerated by evacuating the bed, and the inert gas-hydrocarbon vapor mixture produced by the evacuation is concacted with a liquid absorbent (at 90) whereby a major portion of the hydrocarbons is absorbed therefrom and recovered. The evacuation of the beds (12, 14) is accomplished using a vacuum pump (80) with an integral cooling jacket for cooling the pump as well as the fluids pumped thereby. A cooling medium such as the rich liquid absorbent produced in the process is caused to flow through the vacuum pump cooling jacket thereby cooling the pump (80) and the inert gas-hydrocarbon mixture pumped thereby.

Respiratory and inert gas exchange during high-frequency ventilation.

Abstract: Pulmonary gas exchange during high-frequency low-tidal volume ventilation (HFV) (10 Hz, 4.8 ml/kg) was compared with conventional ventilation (CV) and an identical inspired fresh gas flow in pentob...

Catalytic curing of coatings

Abstract: A method of curing a wet catalyst-curable resin on a substrate in which the substrate is passed through a treating zone provided by a sealed vapor-curing chamber connected to sealed entrance and exit ante chambers at respective ends. The ante chambers are each separated from the vapor-curing chamber by a wall provided with a passage having height-adjustable means to limit passage of gas. The substrate is passed in turn through the entrance chamber where the boundary layer of air is substantially replaced by inert gas, through the entrance chamber into the vapor-curing chamber where it is exposed to the catalyst vapor, and then through the exit chamber where the curing vapor is removed. When a web provides the substrate, a jet of curing vapor is impinged on the web surface as it enters the vapor-curing chamber at an angle and at a velocity effective substantially to remove the barrier layer of gas and permeate the coating. In starting up, the entrance and exit chambers and vapor-curing chamber are purged with inert gas thereby to remove air and on termination of the curing operations the vapor-curing chamber is purged with inert gas to remove curing vapor. Apparatus is disclosed for carrying out the method, featuring height-adjustable doors between the vapor-curing chamber and the entrance and exit chambers. Other features are labyrinth seals and turning vanes adjacent to the passage from one chamber to the other to minimize escape of gas.

Process for drying water-wet membranes

Abstract: An improved process for drying water-wet, cellulose ester membranes is described. It has been found that by contacting one side of the membrane with a liquid mixture of a water-miscible, volatile C1 to C6 hydrocarbon and a water-immiscible organic compound, while an inert gas stream or vacuum is maintained on the other surface of the membrane, water can be displaced from the membrane economically, rapidly and without adversely affecting the structure of the membrane. A 1 to 1 volume mixture of isopropanol and isooctane is particularly preferred in this step. The essentially water-free membrane is then dried by applying reduced pressure or an inert gas stream to produce a membrane having exceptional separation characteristics.

Manufacture of aqueous formaldehyde

Abstract: Formaldehyde manufacture by oxidative-dehydrogenation of methanol over a silver or copper catalyst. Aqueous formaldehyde solution is obtained from the reaction and is stripped of methanol and water by a low energy process at relatively low temperature by means of recycled inert gas in a stripping column comprising at least about 1.5 theoretical transfer units for stripping methanol.

Heating silica gel in inert atmosphere before activation

Abstract: A silica hydrogel is contacted with a hydroxy-containing organic compound which is not completely miscible with water but which is sufficiently miscible with water so as to remove water, and thereafter the organic compound is removed by heating in an inert atmosphere prior to activation by heating in air. The heating in the inert atmosphere allows utilizing preferred organic compounds such as C 5 and C 6 alcohols which are desirable from a commercial standpoint because of the easy separation for recycle. In a preferred embodiment, the hydrogel is aged at a pH of 7 to 9 by means of either adding a base or by utilizing a chromium component containing bound nitrogen.

Process for removing light oil from solids

Abstract: Process and apparatus for removing light oil from solids. The invention is particularly applicable to the removal of residual light oil from solids obtained in a process where aqueous solids are mixed with a light fluidizing oil and subjected to dehydration by heat evaporation. Aqueous solids are mixed with a low viscosity, relatively volatile, water-immiscible light fluidizing oil to obtain a mixture which will remain fluid and pumpable after removal of essentially its entire water content. The mixture of solids, water and fluidizing oil is subjected to a dehydration step by heat evaporation whereby substantially all of the water and at least part of the light oil are evaporated and subsequently recovered. The light fluidizing oil is then largely separated from the solids. The solids carrying residual light fluidizing oil are then brought into direct contact with a hot, inert gas, referred to herein as "blowing gas." The hot, inert blowing gas effects the removal of the residual light oil from the solids. Light oil vapor removed from these solids is separated from effluent blowing gas by condensation and recovered. Effluent blowing gas, free of light oil vapor, may be recycled.

High Temperature Postirradiation Materials Performance of Spent Pressurized Water Reactor Fuel Rods under Dry Storage Conditions

Abstract: Postirradiation studies on failure mechanisms of well-characterized pressurized water reactor rods were conducted for up to a year at 482, 510, and 571°C in limited air and inert gas atmospheres. N...

Low pressure inert gas discharge device

Abstract: A lamp primarily containing neon gas is supplied with alternating electrical power at a frequency of not less than 5 kHz The discharge current is determined on the basis of the gas pressure such that no striations occur If necessary, getter means including a metal element belonging to the second, third, fourth or fifth periodic group are provided near each electrode, oriented so as not to interfere with any electron emissions from the lamp electrodes

Method for determining borehole or cavity configuration through inert gas interface

Abstract: A method for determining the erosion of a borehole or cavity by providing a source of liquid inert gas, preferably nitrogen, placing the inert gas in a storage tank, and suspending the storage tank so that one may determine the actual weight of the nitrogen as it is withdrawn from the tank in liquid state. There is further provided hydraulic means for lifting or lowering the storage tanks suspended from a weight cell as a tank is placed into use or non-use. Further, the liquid nitrogen is pumped from the storage tank with the use of a reciprocating pump, and converted into gaseous nitrogen (in the state of 100° F.,) and is injected into a borehole or the like. The nitrogen gas is then allowed to flow under a certain pressure down the borehole, and due to the properties of nitrogen gas, the nitrogen interfaces at a horizontal plane as it moves down the borehole.

An experimental study on the opening of laminar diffusion flame tips

Abstract: Using an enclosed cylindrical burner, the possible opening of laminar diffusion flame tips was experimentally investigated for various kinds of fuel/inert gas mixtures. The results show that for the ternary mixture of hydrogen, propane, and the inert gas(nitrogen, argon or carbon dioxide), in which the molecular weight of the inert gas is much greater than that of hydrogen, tip opening is indeed possible when the mixture is considerably diluted with the inert gas, whereas for the ternary mixture of hydrogen, propane, and helium, the flame temperature (the maximum temperature in the reaction zone) increases towards the tip of the flame, burning is intensified at the tip, and hence tip opening is not possible. In addition, it is found in hydrogen/carbon dioxide mixtures that tip opening occurs at a constant hydrogen concentration independent of the inner mixture velocity and the outer air velocity. This tip behavior of diffusion flames is in qualitative agreement with the diffusional stratificationmechanism and is also similar to that of premixed flames, suggesting the interesting possibility of the dominance of the diffusional stratification mechanisms in the opening of both premixed bunsen flame tips and laminar diffusion flame tips.