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In many manufacturing and service industries, a need exists for a nondestructive test to determine the presence of hydrogen in a material system. The feasibility of such a system is examined here. Acoustic emission activity resulting from a microhardness indentation is employed to detect hydrogen in A106 and 4340 steel bars following cathodic, gaseous, and chemical charging. These tests show a large increase in emission energy after charging followed by a drop to precharge levels with time. These activity levels are used to calculate hydrogen diffusivity and binding energy of hydrogen to traps in the steel. A mechanism of acoustic emission generation is proposed involving the breakaway of dislocations from Cottrell-like hydrogen atmospheres. The effects of surface roughness and microstructure are also evaluated. Testing of various surfaces indicates that limited surface preparation is necessary prior to implementing the test procedure. Low activity levels before and after charging in 4340, and in martensitic and bainitic A106 indicate possible difficulties in applying the test to harder, more dispersed structures. Despite this limitation and a large amount of scatter in the acquired data, the results indicate that acoustic emission monitoring of microhardness indentations may be of value in detecting the presence of hydrogen in metals and as a research tool in the study of hydrogen transport and embrittlement mechanisms. / M.S.

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No description available.

Torsional fatigue tests were conducted on 4370 steel oil quenched and tempered at 1000° F in (l) the uncharged state, (2) the hydrogen charged state, and (3) in a hydrogen environment. The tests were conducted on both smooth (K_t = l.l) and V-notch (K_t = 3.8) test specimens. A statistical analysis conducted at the 99% confidence limit for the smooth test specimens indicated that precharging with hydrogen increased the fatigue life of the material and also the fracture surface of the test specimens changed from a circumferential crack to a 45° diagonal crack. At a 90% confidence limit, charging with hydrogen did not affect the fatigue life of the V-notched specimens. At a 99% confidence limit for both the smooth and V-notched test specimens, testing in a hydrogen environment increased the fatigue life of the material. Bending fatigue tests were also conducted on the same material and the results indicated that charging with hydrogen decreased fatigue life of smooth test specimens (K_t = l.l) but increased the fatigue life for V-notched specimens (K_t = 2.4 and 3.8). / Ph. D.

M.S.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Subramanian Suresh. / Sc.D.

M. Tech. Hydrogen storage modeling. / In this dissertation, a 2D dynamic simulation for a portion of metal hydride based hydrogen storage tank was performed using computational software COMSOL 4.0a Multiphysics. The software is used to simulate the diffusion and heating of hydrogen in both radial and axial directions. The model consists of a system of partial differential equations (PDE) describing two dimensional heat and mass transfer of hydrogen in a porous matrix. This work provides an important insight to the fundamental understanding of multi-physics coupling phenomena during hydrogen absorption/ desorption process. The simulation results could be applied to the on-board hydrogen storage technology, in particular for the hydrogen supply of a fuel cell for powering of a hydrogen fuel cell vehicle.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016. / The Water Gas Shift (WGS) reaction describes the reaction between carbon monoxide and water vapour to produce carbon monoxide and hydrogen. This work describes the application of a Palladium-Silver (Pd-Ag)-based membrane film reactor, wherein the Pd-Ag film was supported by porous stainless steel (PSS), for the potential replacement of the current multi-stage WGS reaction. The objective of this work was to develop a better understanding of impediments which are relevant to the application of Pd-Ag membrane reactor for the WGSR. The long term behaviour (hydrogen permeability and selectivity) of Pd-Ag membrane under hydrogen exposure was studied, and the use of the Pd-Ag membrane reactor to produce hydrogen through the WGSR was also performed. A detailed literature review was conducted, based on the information gathered from literature. A Permeability and WGS reaction testing stations was designed and built. A thin (20μm) 77%wtPd-23%wtAg film was purchased from Takanaka Company in Japan. The membrane film was enclosed between two stainless steel plates to form a membrane reactor. The membrane reactor was fitted at the two different testing stations.