Effect of Inert Gas Pressure and Solubility on Fused Salt Conductance. I. Argon and Helium with Sodium Nitrate1

1966 ◽  
Vol 70 (1) ◽  
pp. 181-186 ◽  
Author(s):  
James L. Copeland ◽  
Walter C. Zybko
Keyword(s):  
Gas Pressure ◽  
Inert Gas ◽  
Fused Salt

Application of In Situ 3D Computed Tomography during PVT Growth of 4H-SiC for the Study of Source Material Consumption under Varying Growth Conditions

2016 ◽  
Vol 858 ◽  
pp. 49-52 ◽  
Author(s):  
P.J. Wellmann ◽  
Lars Fahlbusch ◽  
Michael Salamon ◽  
Norman Uhlmann
Keyword(s):  
Growth Parameters ◽  
Growth Conditions ◽  
Source Material ◽  
Gas Pressure ◽  
Inert Gas ◽  
Material Surface ◽  
Growth Interface ◽  
Axial Temperature ◽  
The Stability

2D and 3D in-situ X-ray visualization was applied to study the behavior of the SiC source material during PVT growth under various growth conditions. Experiments were carried out in two growth chambers for the growth of 3 inch and 4 inch crystals. Growth parameters were varied in the gas room in terms of axial temperature and inert gas pressure. The study addresses the stability of the SiC source material surface. It is shown that a higher inert gas pressure (e.g. 25 mbar) inhibits an unintentional upward evolution of the SiC feedstock that interferes with the crystal growth interface. The latter is related to a suppression of a pronounced recrystallization inside the SiC source. For a low inert gas pressure (e.g. 10 mbar) it is concluded that the axial temperature gradient inside the source material needs to be decreased to less than ca. 10 K/cm.

scholarly journals Growth of Functional FeTi Clusters Covered with Carbon Layer

2008 ◽  
Vol 2008 ◽  
pp. 1-3
Author(s):  
Chihiro Kaito ◽  
Akihito Kumamoto ◽  
Ryoichi Ono ◽  
Yoshio Saito ◽  
Shigeru Morikawa
Keyword(s):  
Cluster Formation ◽  
Carbon Layer ◽  
Gas Pressure ◽  
Inert Gas ◽  
Graphitic Layer ◽  
Gas Atmosphere ◽  
Ar Gas

FeTi clusters with a diameter of less than 10 nm and covered with a graphitic layer have been preferentially produced in an gas atmosphere at pressures of 10 and 26.6 kPa by the simultaneous evaporation of Fe and Ti wires from a concave carbon boat. To compare this result with cluster formation in an inert gas atmosphere, the result for an Ar gas pressure of 10 kPa is also discussed. The formation of disordered FeNi clusters predominately took place in an gas atmosphere.

Cofferdam and Hyperbaric “Live” Repair of Gas Pipeline Leaks

2016 ◽  
Author(s):  
Jens P. Tronskar ◽  
Chon Gee Lee
Keyword(s):  
Power Plants ◽  
Thermal Analyses ◽  
Gas Pressure ◽  
Third Party ◽  
Inert Gas ◽  
Original Design ◽  
Relief Valve ◽  
Repair Method ◽  
Gas Leak ◽  
Water Depths

Offshore pipelines may face many threats. Apart from internal and external corrosion third party threats represent major hazards to submarine pipelines. Recent pipeline leaks caused by third party as well as construction and installation have been repaired online in a two-step process involving installation of a leak clamp followed by a permanent repair by installation of a welded stand-off sleeve. The welding has depending on the water depth been executed in a hyperbaric habitat or in shallow water using purpose built cofferdams. A concept proposed by DNV GL has been successfully applied to repair of leaking submarine pipelines. To ensure the safety of the repair crew the concepts involves using a gas containment barrier installed over a traditional mechanical leak clamp. The gas containment barrier is either purged with inert gas or nitrogen or it is maintained with a constant inert gas pressure that is monitored continuously during the repair. In the event of a sudden gas leak into the gas containment barrier a pre-set pressure relief valve will open and dump the gas leak outside the habitat. This paper describes the details of a few cases of leaking submarine gas pipelines and the immediate causes of the leak, the repair method selection, the repair method details, cofferdam or hyperbaric welding qualification and execution. The paper also describes the various steps in the process to ensure that the pipeline damage is stable and that the repairs can be safely undertaken to restore the pipelines to their original design condition without reduction of pressure or flow rate. The paper describes the method of global and local finite element analyses as well as fracture mechanics assessment by FEA to assess the stability of the flaws causing the gas leaks. The pipelines in question have all been gas transmission lines carrying gas to gas fired power plants for which gas pressure reduction or shutdown were completely unacceptable. Future development is expected to involve development of remotely controlled repairs using similar concepts at water depths where diver/welders cannot be employed due to the various country regulations or simply because the water depths are too deep for saturation divers. Methodology according to DNV RP-A203 [1] is described for qualification of new technology for underwater pipeline repairs. Further references are made to the recent updates to the DNV RP-F113 Pipeline Subsea Repair [2] with regards to requirements for “live” pipeline repairs. The DNV RP-F113 refers to the PRCI Weld Thermal analyses [3] and requirements to perform full scale mock-up tests of the repair as part of the repair method qualification based on DNV OS-F101 Submarine Pipelines [4].

The electrocatalytic hydrogenation of phenanthrene at Raney nickel electrodes: the influence of an inert gas pressure

1998 ◽  
Vol 43 (12-13) ◽  
pp. 1697-1703 ◽  
Author(s):  
Richard Menini ◽  
Anna Martel ◽  
Hugues Me ́nard ◽  
Jean Lessard ◽  
Olivier Vittori
Keyword(s):  
Raney Nickel ◽  
Gas Pressure ◽  
Inert Gas ◽  
Electrocatalytic Hydrogenation ◽  
Nickel Electrodes

scholarly journals Use of Orthogonal Arrays in Design of a Fuzzy Logic Controller to Predict the Proof Stress for the TIG Welded Al-65032

2020 ◽  
Vol 9 (7) ◽  
pp. 996-1001
Keyword(s):  
Fuzzy Logic ◽  
Data Base ◽  
Material Properties ◽  
Fuzzy Logic Controller ◽  
Gas Pressure ◽  
Tig Welding ◽  
Inert Gas ◽  
Welding Parameters ◽  
Proof Stress ◽  
Preheating Temperature

Fuzzy logic controller (FLC) is well suited where there is a considerable amount of uncertainty in the process. The material properties of a weldment in TIG welding depend on welding parameters like shielding gas pressure, current, torch angle, Electrode size, electrode projection, arc length etc. It is also influenced by the joint parameters like groove angle, land, root gap, preheating temperature. But a lot of noise parameters like variation of base material properties, variation in quality of inert gas used, variation in ambient conditions, variation in workman ship etc introduce uncertainties in the into the process. To deal with such uncertainties an FLC is designed and validated. In the current work, four parameters namely inert gas pressure, current, groove angle of the joint and preheating temperature of base metal are considered as input variables and the influence of these variables on the 0.2% proof stress is studied. Three linguistic terms are used for each parameter. To minimise the number of experiments in designing data base an L-9 orthogonal array is chosen for experimentation. TIG welding is carried and data base with 9 rules are formulated. For the input and out variables Triangular membership function is selected and FLC is designed. The FLC is validated with 5 more experiments. Mamdani approach is used to develop the Fuzzy controller.

scholarly journals Modeling of Bending Properties of Stainless Steel 304 Sheets Welded by Tungsten Inert Gas Welding Process

2019 ◽  
Vol 15 (4) ◽  
pp. 10-22
Author(s):  
Ali Hussein Alwan
Keyword(s):  
Stainless Steel ◽  
Welded Joints ◽  
Gas Pressure ◽  
Inert Gas ◽  
Welding Parameters ◽  
Tungsten Inert Gas Welding ◽  
Bending Properties ◽  
Argon Gas ◽  
Bending Force ◽  
Stainless Steel 304

In this research, the effects of both current and argon gas pressure on the bending properties of welded joints were studied. Using the possible ranges of welding gas pressures and currents, Tungsten inert gas welding (TIG) of stainless steel (304) sheet was used to obtain their influence on the maximum bending force of the (TIG) welded joints. Design of experiment (DOE) ‘version 10' was used to determine the design matrix of experiments depending on the used levels of the input factors. Response surface methodology (RSM) technique was used to obtain an empirical mathematical model for the maximum bending force as a function of welding parameters (Current and Argon gas pressure). Also, the analysis of variance (ANOVA) was used to verify the adequacy of the resulted model statistically.  

THE CHEMISTRY OF SINGLET AND TRIPLET METHYLENE

1965 ◽  
Vol 43 (6) ◽  
pp. 1631-1644 ◽  
Author(s):  
R. F. W. Bader ◽  
John I. Generosa
Keyword(s):  
Trans Isomer ◽  
Singlet State ◽  
Gas Pressure ◽  
The Other ◽  
Inert Gases ◽  
Inert Gas ◽  
Initial Decrease ◽  
Percentage Yield ◽  
Excited Molecules ◽  
Subsequent Rise

Results are reported for the photolysis of small, fixed amounts of diazomethane and cis-butene-2 in the presence of increasing pressures of the inert gases He, Ar, Xe, N2, and CF4. The variation in the percentage yield of the trans-dimethylcyclopropane as a function of the inert gas pressure indicates that two basic mechanisms, with opposite dependencies on the inert gas pressure, are responsible for its formation. An initial decrease in the percentage yield of this trans isomer with increasing pressure indicates that a source is an isomerization of energized molecules. These excited molecules result from the addition of methylene in a singlet state to cis-butene-2. A subsequent rise in the yield of the trans isomer with further increases in the pressure indicates that another mechanism, one whose rate is increased by an increase in pressure, must be present. This is attributed to a mechanism involving triplet methylene. The pressure regions for the observation of the singlet or triplet behavior of methylene are thus known and the modes of formation of the other C5 products may be determined.

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