Showing papers on "Inert gas published in 1970"

Field Adsorption of Inert-Gas Atoms on Field Ion Emitter Surfaces

Abstract: Theories of field ionization assume an atomically clean surface. Atom-probe experiments surprisingly revealed that the inert imaging gases are adsorbed at the field ion emitter. It is shown that this adsorption is due to a short-range field-induced dipole-dipole interaction. Adsorption at the apex of the protruding surface atom has considerable consequences for the mechanism of field ionization and field evaporation.

The Design and Some Emission Characteristics of an Economical dc Arc Plasmajet Excitation Source for Solution Analysis

Abstract: DC plasma arc jet excitation and emission characteristics for solution analysis with economical inert gas flow rates

A kinetic theory of steady condensation

Abstract: This paper pertains to the steady condensation on to, or evaporation from, a liquid droplet suspended in a mixture of its vapour and an inert gas. The treatment is from a kinetic theory viewpoint. The Maxwell moment method is used with Lees' two stream Maxwellian representations for the distribution functions, to obtain a closed form result valid through the whole range from free molecule to continuum. In the diffusion control limit the formula reduces to approximate results obtained by Maxwell, Fuchs and others. In the limit where no inert gas is present the formula reduces to a result obtained earlier by the author. The formulae presented here for the mass and energy flux can now be used to calculate the growth rate of very small droplets, under a wide range of conditions.

High pressure mercury vapor discharge lamp with metal halide additives

Abstract: A high pressure mercury vapor discharge lamp having a quartz glass discharge tube and refractory metal electrodes in an envelope containing metal halides and an inert gas as the additive fill. The discharge tube contains halides of at least three elements which have essentially similar median excitation energy which comprises dysprosium and at least two other rare earth metals. The dysprosium and the at least two other rare earth metals are present in a total amount of from 0.3 to 1.2 mg/cm of arc length which during operation of the lamp provides a saturated vapor pressure and a wall loading of between 8 and 20 W/cm2.

Water cooling method and apparatus employing liquid nitrogen

Abstract: Water is cooled by the direct injection thereinto of liquid nitrogen. Preferably, heat is applied in the vicinity of the injection zone and preferably the injection of the liquid nitrogen is intermittent with inert gas being injected when liquid nitrogen is not injected. The application of the heat and the injection of the gas eliminates the tendency of the injector to be plugged by ice formation.

Collision‐Induced Singlet→Triplet Intersystem Crossing of Methylene and Methylene‐d2

Abstract: The photolysis of ketene or ketene‐d2 in the presence of propane, oxygen, and inert gas was studied at 300°K at each of the four wavelengths 2600, 3130, 3340, and 3500 A. Inert gases used were He, Ar, Xe, N2, and CF4. The inert gases cause the transition of methylene from the first singlet state to the triplet ground state to occur. The observed kinetics of the intersystem crossing process, being first order in methylene and first order in inert gas, are second order. The second‐order rate constants, relative to the rate constant for reaction of singlet methylene with propane, are independent of wavelength, and increase in the order He

Surface modification of carbon fibers

Abstract: A PROCESS IS PROVIDED FOR MODIFYING THE SURFACE CHARACTERISTICS OF A CARBONACEOUS FIBROUS MATERIAL (I.E. EITHER AMORPHOUS CARBON OR GRAPHITIC CARBON) AND TO THEREBY FACILITATE ENHANCED ADHESION BETWEEN THE FIBROUS MATERIAL AND A MATRIX MATERIAL. THE CARBONACEOUS FIBROUS MATERIAL IS CONTACTED FOR RELATIVELY BRIEF RESIDENCE TIME WITH AN EXCITED GAS SPECIES AT A MODERATE TEMPERATURE OF ABOUT 20 TO 325*C. GENERATED BY APPLYING HIGH FREQUENCY ELECTRICAL ENERGY IN PULSED FROM TO A GASEOUS MIXTURE COMPRISING ING AN INERT GAS AND A SURFACE MODIFICATION GAS. COMPOSITE ARTICLES OF ENHANCED INTERLAMINAR SHEAR STRENGTH MAY BE FORMED BY INCORPORATING THE FIBERS MODIFIED IN ACCORDANCE WITH THE PRESENT PROCESS IN A RESINOUS MATRIX MATERIAL.

Production of Levoglucosan by Pyrolysis of Carbohydrates. Pyrolysis in Hot Inert Gas Stream

Abstract: Starch pyrolysis was carried out in a hot gas stream to establish optimum conditions for the production of levoglucosan. Helium, nitrogen, and steam were used. Steam was most effective and convenient because of its high heat capacity and because it is easily condensed. Yields of levoglucosan increased as pressures decreased. The effect of temperature, feed weight, gas flow rate, reduced air pressure, and catalyst on the yield of levoglucosan is reported. Optimum operating conditions for the acid-catalyzed process were established. A maximum yield of 44.5% levoglucosan was obtained from cornstarch.

Ion bombardment induced phase transformations and inert gas mobility in the semiconductors Ge, Si, and GaAs

Abstract: The present study contributes some new aspects to the general understanding of the ion implantation behaviour of 3 common semiconductor materials, and of diffusion processes in these materials. Single crystals of Si, Ge, and GaAs were bombarded with Kr- or Xe-ions at energies of 40 or 500 keV and doses between 1011 and 2 × 1016 ions/cm2. Gas release measurements and Rutherford scattering of 1 MeV He+-ions combined with channeling were used to study bombardment damage (amorphization) and inert gas diffusion. At low bombardment doses (1011 ions/cm2) and energy (40 keV), no damage was observed and the gas release was compatible with volume diffusion resembling Group I and VIII behaviour. Hence, the pre-exponential terms, D 0, were low (range 10-5±1 cm2 sec−1) and the activation enthalpies, Δ H, were much lower than those of self-diffusion or of diffusion of Group III and V elements. The Δ H's for gas diffusion followed the relation Δ H = (1.05±0.1) × 10−3 Tm eV with the melting point, Tm , in °K. Th...

Transversely Spark‐Initiated Chemical Laser with High Pulse Energies

Abstract: Peak powers exceeding 1 kW of 5.0‐μ radiation have been obtained from a pulsed chemical laser. Reactions of CS2/O2/inert gas mixtures were initiated by means of a transverse spark discharge. A maximum pulse energy of 26 mJ was obtained. The pumping reaction was believed to be O+CS=CO+S. Laser action was observed on 79 P‐branch transitions in the 13→12 to 2→1 transitions of ground state CO.

Manganese zinc ferrite core with high initial permeability

Abstract: A FERROMAGNETIC STRUCTURAL ELEMENT HAVING INITIAL PERMEABILITY HIGHER THAN 4000 IN THE OPERATING TEMPERATURE RANGE OF -50*C. TO +120*C. COMPOSED OF 54 TO 58 MOL PERCENT OF FE2O3 10 TO 24 MOL PERCENT OF MNO AND 18 TO 36 MOL PERCENT OF ZNO AND CONTAINING LESS THAN 0.05% BY WEIGHT OF IMPURITIES AND A METHOD OF MANUFACTURING THE SAME. THE METHOD INCLUDES MIXING THE ABOVE COMPONENTS AND SINTERING THEM AT 1270*C. TO 1300*C. FOR 4 TO 20 HOURS, WITH AT LEAST THE LAST HALF OF THE SINTERING TAKING PLACE IN AN INERT ATMOSPHERE HAVING LESS THAN 0.2% BY VOLUME OF OXYGEN AND COOLING THE SINTERED FERRITE TO ABOUT 300*C. IN THE SAME INERT ATMOSPHERE.

Device for improving reactions between two components of a metallurgical melt

Abstract: A method of improving the reaction between two components of different specific gravity or for homogenizing mixtures of components of different specific weight at least one of which is a fluid such as between a metallurgical melt and a slag layer, comprises producing a flow in the reaction zone between the two liquids of different specific gravities or specific weight and simultaneously introducing gaseous medium into the area of the reaction zone between the surfaces of the two layers. For this purpose, an inert gas may be used or a gas such as oxygen or hydrogen which will react with at least one phase or component of the mixture. It is also desirable in some instances to introduce a gas having a desulfurizing effect. An apparatus for carrying out the method including a rotating pump element disposed to draw the heavier liquid upwardly and discharge it adjacent the surface of the lighter liquid and which includes means for discharging a gas in the vicinity of the surface of the lighter liquid or upwardly and through the pump.

Hot-gas machine comprising a heat transfer device

Abstract: A hot-gas engine including a heater and a source of heat in combination with a switching device for conveying heat from the heat source to heater, the device including a pair of spaced heat pipes with third intermediate heat pipe and means for introducing inert gas into said third heat pipe and removing said gas to vary the vaporization point therein and the rate of heat transfer therethrough.

Thermal Effects Accompanying Spontaneous Ignitions in Gases. I. An Investigation of the Heating Effects Which Accompany the Rapid Admission of Inert Gas to an Evacuated Vessel

Abstract: In experiments on spontaneous ignition of gases, transient temperature changes normally accompany the entry of gases to evacuated vessels. They may invalidate much quantitative experimental work and give rise to spurious observations. In the present investigation, temperature–time histories accompanying gas entry have been mapped with a fine (13 μ m) thermocouple for many positions in a spherical vessel. It is found that although transient (characteristically, 0.1 s), the temperature rises can be large—perhaps 200 °C—and are appreciable even for gases at low pressures. They arise from adiabatic heating of the entering gas. Experiments with 18 different gases show that heating is greatest for monatomic molecules (large γ ; low C v ) and least for complex molecules (small γ ; large C v ). The effects are mitigated by conductive heat losses; such losses are greatest at low pressures, in small vessels, and for gases of high thermal diffusivity. The effects of convection are apparent at higher pressures. The implications of the results are various. Not only do they concern many laboratory measurements on spontaneous ignition, but they are also important for the large-scale handling of potentially reactive gases or gas mixtures, especially involving simple small molecules (as in mixtures with air, halogens or oxygen).

Production of improved polymeric materials using electrical gas discharges

Abstract: A METHOD OF INCREASING THE SOLVENT RESISTANCE OF THE SURFACE OF A POLYMERIC MATERIAL BY EXPOSING THE SAME TO THE ACTIVE SPECIES FORMED BY AN ELECTRIC DISCHARGE IN A GASEOUS MIXTURE AT A PRESSURE OF AT LEAST 100 MM. OF MERCURY WITH THE GASEOUS MIXTURE MADE UP MAINLY OF AN INERT GAS SUCH AS ARGON AND A MINOR PROPORTION OF ANOTHER GAS SUCH AS OXYGEN WHICH MODIFIES THE ACTIVE SPECIES IN THE DISCHARGE PLASMA.

Ozone Ultraviolet Photolysis. II. Quantum Yield at Low Ozone Concentration

Abstract: The relative ultraviolet quantum yield was measured at low ozone concentration (∼ 0.2 torr) in order to identify contributing processes under conditions where the Norrish chain mechanism is not expected. The quantum yield in pure O3 and in O3–He mixtures exceeds that in O3–N2 mixtures by a component φx ≈ 2 which is attributed to the products of the O(1D) + O3 reaction. These products decompose ozone with a rate constant k ≤ 107liter/mole·sec and are not affected by a large excess of inert gas. This result tends to rule out O2(3Σu+) as the reactive product.

Device for sealing gap between electrode and lining of electric arc furnace

Abstract: A sealing device for the gap between an electrode and a lining of an electric furnace comprises a chamber through which the electrode passes. This chamber is supplied with an inert gas under pressure from the holes of at least two curved headers which form a ring around the electrode. Installed between the headers and the part of the chamber through which the electrode passes are vanes which form identical acute angles with a respective radius drawn from the center of the chamber to the base of each vane, for creating a circular flow of the inert gas around the electrode. As a result, a gas flow is created near the electrode, preventing escape of gases from the furnace into the atmosphere.

Production of Levoglucosan by Pyrolysis of Carbohydrates. Pyrolysis in Hot Inert Gas Stream

Abstract: Starch pyrolysis was carried out in a hot gas stream to establish optimum conditions for the production of levoglucosan. Helium, nitrogen, and steam were used. Steam was most effective and convenient because of its high heat capacity and because it is easily condensed. Yields of levoglucosan increased as pressures decreased. The effect of temperature, feed weight, gas flow rate, reduced air pressure, and catalyst on the yield of levoglucosan is reported. Optimum operating conditions for the acid-catalyzed process were established. A maximum yield of 44.5% levoglucosan was obtained from cornstarch.

Method of assemblying compound body

Abstract: An outer cylindrical hody composed of a fiber reinforced thermal setting synthetic resin and a cylindrical inner metal body are separately immersed in a bath of cyrogenic liquefied inert gas. The metal body shrinks and is then inserted in the outer body. Upon being removed from the bath and heated, the metal body expands and becomes firmly bonded to the outer body to form the compound body.

Method of making a permanent-magnetisable body of compressed fine particles of a compound of m and r

Abstract: A method of manufacturing a permanent magnet from compressed M5R powder (M is, for example, Co, R is a rare earth or Th) The powder is obtained by grinding castings in oxygen- and water-free environments in an inert gas or an inert liquid The resultant magnet exhibits a small ageing effect, while in addition magnets of higher density can be obtained

Emanation and Surface Gas Labeling Methods of Studying the Solid‐State Reaction of ZnO and Fe2O3

Abstract: The solid-state reaction of ZnO and Fe2O3 was studied by emanation and surface gas labeling methods based on measurement of radioactive inert gas release. These methods, especially in combination, supplement information on the formation of zinc ferrite. The methods are especially sensitive to initial changes in the material during thermal reaction. Measurement of the release of radon and xenon from the sample, DTA, and dilatometry can be accomplished simultaneously with the apparatus.

Glow discharge polymerization coating of toners for electrophotography

Abstract: The triboelectric properties and minimum caking temperature of particulate toner material can be altered by glow discharge treatment in the presence of an inert gas, air or a gaseous polymerizable material.

Method for the boration of titanium and titanium alloys

Abstract: Metals, especially titanium and titanium alloys, are borated with a borating agent prepared by annealing amorphous boron at a temperature between 850*C and 1,300*C in an inert gas, especially a noble gas. The boration is best accomplished by packing the metal into the borating agent and heating it to a temperature between 900*C and 1,400*C while passing a noble gas through the borating agent. Activators and inert substances can be added to the borating agents.