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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Investigation leading to a process for the synthesis of hydrogen sulphide from sulphur and certain lubricating oils derived from petroleum

Schauder, H January 1952 (has links)
The primary object of the present study was to provide a process adaptable to prevailing South African conditions, for the manufacture of hydrogen sulphide. Such a process would also be suitable for use in other countries where the gas is not obtainable naturally or from refinery operations or as a by-product from other industries. Early in the study it was found that the literature embodying prior work was very scattered in character and had to be sought in many different fields of research. It was therefore decided to make the record of prior work as comprehensive as possible so as to provide, at the same time, a starting point tor future workers on related subjects. Intro., p. 1.
62

The homogeneous catalytic activation of molecular hydrogen by cupric salts in aqueous solution

Peters, Ernest January 1956 (has links)
Hydrogen, which is relatively inert at ordinary temperatures, was found to be, activated homogeneously in aqueous solution try dissolved cupric salts, as shown by their catalytic effect on the reactions between H₂ and reducible substrates such as Cr₂O₇⁼, IO₃⁻, and Ce⁺⁺⁺⁺. From kinetic studies of the Cu(ll)-catalyzed hydrogenation of Cr₂O₇⁼, it was shown that the catalytic activity of Cu⁺⁺ is greatly influenced by complex-forming reagents. The catalytic activities of cupric complexes were found to decrease in the order: butyrate, propionate > acetate > sulphate > chloride > H₂O (i.e. the uncomplexed Cu⁺⁺ ion) > glycine, ethylene-diamine . In all systems that were studied, the reaction was.found to be second order kinetically, the rate being proportional to the concentrations of Cu(ll) and H₂. The occurrence of an H⁺ ion as a product of the initial step of the reaction was postulated to account for the perchloric acid dependence of the rate. The promoting effect of various negative ions, which follows the order of their basicities, was thus explained by assigning to them the role of stabilizing the H⁺ ion. The following mechanism was postulated to account for the observed kinetics: Cu(ll) + H₂ [symbol omitted] CuH⁺ + H⁺ CuH⁺ + substrates [symbol omitted] Cu(ll) + products CuH⁺, the activated intermediate suggested by this mechanism, also seems on energetic grounds to be the most plausible of the possible intermediates having reasonable classical structures. It is suggested that the catalytic activity of Cu⁺⁺ is related to its electron affinity. An attempt is made to extend this interpretation to other homogeneous and heterogeneous hydrogenation catalysts. / Science, Faculty of / Chemistry, Department of / Graduate
63

I. The temperature coefficient of the - band of formaldehyde. II. The nature of hydrogen-bonding.

Cohen, Abraham David January 1956 (has links)
PART ONE The long wave spectrum of formaldehyde vapour was observed at various temperatures. From this work it was shown that: 1. ) the α-band at 3703Å is a hot band probably arising from a lower state involving the coriolus coupled normal modes of vibration ν₅ = 1 and ν₆ = 1. 2. ) a series of bands designated as the B-bands originate from monomeric formaldehyde vapour and are probably due to a ³π ← n electronic transition. PART TWO The high resolution proton magnetic resonance spectra of hydroxyl hydrogen bonding systems and aldehydes were investigated. From this work it was shown that the forces responsible for hydrogen bonding are mainly electrostatic in nature and that the large magnitude of these forces is probably due to mutual polarization occurring in the molecular aggregates. / Science, Faculty of / Chemistry, Department of / Graduate
64

Atomic hydrogen on the surface of superfluid helium: the sticking probability and polaronic behavior

Zimmerman, Dan Simon January 1982 (has links)
A study is made of the interaction between hydrogen atoms and the surface elementary excitations of superfluid "He. Calculations for the sticking probability and for the energy and effective mass of a hydrogen atom bound to the surface are presented. As a first step in the calculations, we formulate the Hamiltonian describing a hydrogen atom interacting with the surface of "He in its ground state together with the interaction coupling to the surface elementary excitations (the ripplons). The derivation is based on the association of the surface ground state with a flat surface and the excited states with a sinusoidally varying height of the surface. The interaction potential is derived by summing a *He-H atom-atom pair potential over helium atoms below the surface. The atom-atom pair potential is chosen so that the derived surface potential is a Morse potential with parameters which are fitted to the effective surface potential derived by Mantz and Edwards for a hydrogen atom interacting with N-1 helium atoms. The energy and angle dependent sticking probability, S(E,θ), and the thermally averaged sticking probability, S(T), are calculated. Results are compared with the experimental value of S(T), S(T)=0.035±0.005, measured for the temperature range 0.18<T<0.27K. The possibility that a hydrogen atom bound above the surface may exhibit polaronic behaviour is investigated. The energy of the hydrogen surface "polaron" and its effective mass are calculated using perturbation theory. The hydrogen atom is found to be weakly coupled to the surface elementary excitations, and therefore the polaronic effects are weak. The contribution to these results from virtual transition to free states is emphasized. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
65

Analysing powers of hydrogen and helium-4 for protons at intermediate energies

Dubois, Richard January 1978 (has links)
An absolute calibration of the analysing powers of hydrogen and helium-4 has been performed at 24° and 15° lab, respectively, for protons between 200 and 520 MeV with a typical uncertainty of ±2%. In a double scattering experiment, the TRIUMF polarized proton beam was scattered, first at 15° on a liquid helium target, then a second time at 24° on a polyethylene target. The method combines the advantages of the very high analysing power of helium and the small difference in incident energies on both scatters. The analysing power of helium-4 was measured to be 0.964 ± .012, 0.792 ± .011 and 0.476 ± .018 at energies of 222, 325 and 518 MeV, respectively. The analysing power of hydrogen was found to be 0.294 ± 0.003, 0.354 ± 0.005 and 0.412 ± 0.013 at proton energies of 205, 308 and 499 MeV, respectively. This represents a great improvement over previous p-p data which was not known to better than ±6%, and so will permit a more accurate determination of nucleon-nucleon phase shifts. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
66

A Correction Factor for the First Born Approximation

Russell, Jerry Brent 01 1900 (has links)
This thesis looks at a Schroedinger equation and the Born approximation.
67

The surface catalysis of the ortho-para conversion in liquid hydrogen by paramagnetic oxides on alumina /

Cunningham, Clarence Marion January 1954 (has links)
No description available.
68

The surface catalysis of the ortho to para conversion in hydrogen under pressure at liquid nitrogen temperature /

Chapin, Douglas Scott January 1954 (has links)
No description available.
69

Relaxation studies of low ortho concentration solid hydrogen at very low temperatures /

Constable, James Harris January 1969 (has links)
No description available.
70

An investigation of spontaneous ignitions in flowing hydrogen air mixtures /

Neer, Michael Earnest January 1972 (has links)
No description available.

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