[en] This thesis describes experiments studying nuclear spin transport in spin polarized hydrogen gas at temperatures between 150 mK and 700 mK, and number densities between 1 x 10¹⁵ cm^-3 and 9 x 10¹⁶ cm^-3. Pulsed Fourier transform and CW NMR were used for this purpose. The surfaces were coated with ⁴He for all the experiments. The observed NMR spectrum showed sharp resonances superimposed on a broader background. The background was attributed to the NMR image of the NMR sample volume. The sharp resonances were attributed to standing spin waves modes in this volume. As recombination of the sample induced a large nuclear polarization, the spin wave resonances became narrower, more numerous, and more intense, as predicted by theory. The magnetic field gradient confined the observed spin wave modes to one side of the sample volume. The ordinary diffusion coefficient D₀ was measured by observing the recovery of the longitudinal polarization in the NMR sample volume after a large tipping angle pulse due to diffusion of spins from outside the sample volume. By calculating the theoretical spectrum and comparing it with the observed spectrum, the dimensionless parameter μ was measured. This parameter determines the quality factor Q of the spin wave modes

[en] This patent describes a method of preparing an oriented superconductive ceramic oxide. It comprises directing a stream of essentially pure ozone at the surface of a heated substrate while evaporating the metallic components of the super conductive ceramic oxide onto the surface so that a layer of the superconductive ceramic oxide is formed thereon without need of further annealing

No abstract available

[en] Growth rates for the denitrifying bacteria Pseudomonas Stutzeri were studied to minimize the time necessary to start up a bacterial denitrification reactor. Batch experiments were performed in nine 250-ml Erlenmeyer flasks, a 7-liter fermentor, and a 67-liter fermentor. All reactors maintained an anaerobic environment. Initial microorganism inoculum concentration was varied over four orders of magnitude. Initial nitrate and substrate carbon concentrations were varied from 200 to 6000 ppm and from 56 to 1596 ppm, respectively, with a carbon-to-nitrogen weight ratio of 1.18. In all experiments, except those with the highest initial substrate-to-bacteria ratio, no growth was observed due to substrate depletion during the lag period. In those experiments which did exhibit an increase in bacterial population, growth also stopped due to substrate depletion. A model simulating microbe growth during the induction period was developed, but insufficient data were available to properly adjust the model constants. Because of this, the model does not accurately predict microbe growth. The metabolism of Pseudomonas Stutzeri was studied in detail. This resulted in a prediction of the denitrification stoichiometry during steady state reactor operation. Iron was found to be an important component for bacterial anabolism

No abstract available

[en] This report investigates one- and two-dimensional rational approximants as a convenient systematic means for analytical representation of numerical data for molecular potential energy surfaces. Discussed in this paper are the linearized least-square equations for determination of Pade approximants and the iterative method for the elimination of zeros as demonstrated for the cases of Li₂ and two-mode HCN

[en] True UHV, in situ preparation of thin films of the YBa/sub 2/Cu/sub 3/O/sub 7-x/ oxide has been accomplished for the first time using a pure jet of ozone applied during the evaporation of the metal constituents. The new process has yielded films that are superconducting at 82K with a transition onset at 87K. The new method has significant potential for improving film quality. It also creates new opportunities for the in-situ measurement of superconducting properties of thin film surfaces, and for the fabrication of superconducting devices

[en] Cross sections for the vibrational excitation of H₂O in collision with O(³P) are calculated for relative collision energies of 0.5 to 3.0 eV by the vibrational close-coupling rotational infinite order sudden method using an accurate potential energy surface. The excitation cross sections obtained by this quantum mechanical calculation are compared to results of a recently published quasiclassical trajectory study which used the same potential surface. Very large differences between the quantum mechanical and classical trajectory results are found

[en] High-temperature superconducting microbolometer silicon microstructure infrared arrays offer the potential of lowest possible production cost combined with high performance for use in infrared imaging systems. Linear arrays employing thin films of yttrium barium copper oxide have been prepared. Small two-dimensional arrays are under development. A 240 x 336 array of 50 μm x 50 μm pixels operating at 85 K at 30 frames per second with f/1 optics has a theoretical noise equivalent temperature difference of 2.0 x 10^-3 deg K

[en] 'Dimensionally Stable Anodes'(DSA) have gained wide acceptance in electrochemical production of chlorine and caustic soda. The materials for DSA formulation include the precious metals iridium, ruthenium and rhodium, the non-precious metals tin, antimony and manganese, and the valve metals titanium and tantalum. The present paper describes the determination of ruthenium and tin by energy-dispersive X-ray fluorescence. (U.K.)