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Showing 1 to 20 of 55 for “"Hydrogen concentration"”.
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Hydrogen concentration and temperature affect the 1/f resistance noise in niobium films
… 60 K to 400 K. The resistance noise came from hydrogen ions and other defects placed in the films during sputtering. Hydrogen ions cause three types of 1/f noise at different temperatures. The noise is related to internal friction phenomena such as the Gorsky effect and the Snoek effect. Near …
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Hydrogen concentration and temperature affect the 1/f resistance noise in Nb films
… 60 K to 400 K. The resistance noise came from hydrogen ions and other defects placed in the films during sputtering. Hydrogen ions cause three types of 1/f noise at different temperatures. The noise is related to internal friction phenomena such as the Gorsky effect and the Snoek effect. Near …
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Investigation of the effects of pressure and hydrogen concentration on ammonia synthesis under neutron irradiation
… to determine the effects of mild pressures and hydrogen concentrations on the formation of ammonia by slow neutron irradiation of gaseous hydrogen-nitrogen systems. A secondary purpose of this investigation was to determine the effects of neutron irradiation on ammonia synthesis. Apparatus …
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ΜΕΛΕΤΗ ΤΟΥ ΟΡΙΑΚΟΥ ΣΤΡΩΜΑΤΟΣ ΣΥΜΠΙΕΣΤΟΥ ΡΕΥΣΤΟΥ ΜΕ ΕΦΑΡΜΟΓΗ ΜΑΓΝΗΤΙΚΟΥ ΠΕΔΙΟΥ ΚΑΙ ΕΓΧΥΣΗ ΞΕΝΟΥ ΡΕΥΣΤΟΥ
… FIELD AND INJECTION OF A LIGHT FOREIGNGAS (HYDROGEN) IN THE HYPERSONIC LAMINAR BOUNDARY LAYER OF RAREFIED AIR OVER AFLAT PLATE ARE STUDIED. THE VARIABILITY OF THE MIXTURE PROPERTIES WITH TEMPERATURE AND HYDROGEN CONCENTRATION IS TAKEN INTO ACCOUNT. SLIP BOUNDARY CONDITIONSARE PROVIDED TO …
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Hydrogen in Austenite: What Changes after Martensitic Transformation?
Diffusible hydrogen in steels can cause embrittlement. Hydrogen has much lower diffusivity in austenite than in ferrite. Therefore, austenite is relatively immune to embrittlement. However, the poor stability of austenite can lead to martensitic transformation. And martensite cannot dissolve all …
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Weldability and hydrogen relationships in super duplex stainless steel.
… 50% ferrite, the response of these two phases to hydrogen is of interest to the users of these materials. A study has been made of the hydrogen cracking behaviour in welded super duplex stainless steel using the GTA welding process. The aim of this work was to determine the effects of diffusible …
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Hydrogen in thin film niobium
"An experimental study of hydrogen dissolved in thin films of niobium is presented. The chief techniques used were x-ray diffraction and ion-beam hydrogen profiling. Niobium was grown on sapphire substrates by molecular beam epitaxy, resulting in high quality films. It has previously been shown …
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Hydrogen purity assessment using laser absorption Spectroscopy
Hydrogen purity assessment is a critical concern in energy applications, especially in fields involving hydrogen injection into natural gas pipelines and fuel cell research. This study addresses the limitations of current hydrogen measurement techniques by developing a novel hydrogen spectrometer …
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Electrochemical Hydrogen Absorption by Zr-Cu-Al-Ni Metallic Glasses
Effect of electrochemical absorption of hydrogen has been studied on the Zr-based amorphous alloys. The influence of hydrogen absorption on the stability of the amorphous phase and its crystallisation was investigated. Additionally, the cathodic hydrogen reaction mechanism on the surface of the …
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Interaction of Trapped Hydrogen With Dislocations at Low-Temperature in Deformed Palladium
Given such low hydrogen concentration in the heavily deformed Pd, this behavior is representative of hydrogen trapped at dislocations at low temperature. Correlating the spatial and the vibrational characterization of the Cottrell atmosphere demonstrated the phase behavior of the trapped solute …
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Embrittlement of Austenitic Stainless Steels by Solute Hydrogen
… steel were determined as a function of solute hydrogen concentration. Twenty micron thick foils of types 310s and 304 stainless steel were cathodically precharged to saturation and tested in tension at room temperature. X-ray diffraction experiments were performed to measure the lattice strains …
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Predicting the Influence of Hydrogen on Zirconium
… the CANDU® reactors results in the production of hydrogen or deuterium. Some of this hydrogen enters the alloy and causes a gradual increase in the total hydrogen concentration from the initial average hydrogen concentration during fabrication. In addition to the gradients in temperature and …
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Experimental investigations of isotopologue fractionation during microbial methanogenesis
… methods to test the following hypothesis: hydrogen concentration and redox potential are important controlling factors of carbon (¹³C/¹²C) and hydrogen (D/H) isotope ratios as well as the abundance of methane clumped isotopologues ([delta]¹³CH₃D) during microbial methanogenesis. Chapter 2 …
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Atomistic studies on irradiation damage in iron
… are compared for pure iron and iron with a small hydrogen concentration. Second, the inter- action energy between point defects and line dislocations has been calculated for a number of configurations, using both molecular statics methods and calculations based on linear elastic continuum theory …
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The effects of hydrogen on the deformation and fracture behavior of the metastable beta-titanium alloy, TIMETAL(RTM) 21S
… a sharp ductile-to-brittle transition when the hydrogen concentration is increased slightly above H/M $=$ 0.22. To understand this sharp transition, a series of experiments was devised to test for the possible hydrogen embrittlement mechanisms. In situ straining experiments in an environmental …
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Electrical and mechanical properties of molecular junctions and nano surfaces
… in terms of stiffness and work function as the hydrogen concentration intercalating the interface and the number of graphene sheets on top of the silicon-carbide substrate varies. As a result of this study I have found that the effect of increasing the number of penetrating hydrogen atoms is to …
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Etching of Gallium Arsenide with atomic hydrogen
… (100) GaAs surface during exposure to a known concentration of thermalised hydrogen atoms downstream from an H₂ plasma. Etch rates between 3 and 9 nm/min are followed at constant temperature within the range 229 - 360 °C. Increasing substrate temperature leads to increased rates of reaction. A …
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ΜΕΛΕΤΗ ΤΗΣ ΚΑΤΑΝΟΜΗΣ ΥΔΡΟΓΟΝΟΥ ΣΕ ΛΕΠΤΑ ΥΜΕΝΙΑ ΔΥΟ ΣΤΡΩΜΑΤΩΝ ΔΙΑΦΟΡΕΤΙΚΩΝ ΜΕΤΑΛΛΩΝ
… HAS BEEN EMPLOYED FOR THE DETERMINATION OF THE HYDROGEN DEPTH DISTRIBUTION IN SOME THIN FILMS OF METAL-HYDROGEN SYSTEMS ONTO A STAINLESS STEEL SUBSTRATE. THE INVESTIGATED FILMS WERE: THE SINGLE LAYER FILMS V-H AND TI-H AND THE THIN FILMS SANDWICHES (FILMS CONSISTING OF TWO THIN LAYERS OF …
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Studies of the low temperature anomaly in palladium hydride
… been made to determine the effects of varying hydrogen concentration. The temperature of the resistive peak was seen to increase with H(D)/Pd for ratios above .63. In the second experiment samples of Pd-H and Pd-D with high (T > 70 K) anomaly temperatures have been held below T for extended …
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Hydrogen Distribution in Metal Hydrides and its Effect on Reactor Physics Calculations
… is zirconium hydride which, despite its variable hydrogen concentration, is commonly described using a phonon distribution that corresponds to a single temperature and a single hydrogen concentration. Approximating a range of different hydrogen concentrations and temperatures by a single …
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