In this work, the dependence of the vacuum arc spot velocity on physical and electrical properties of different graphite cathode materials is investigated in the presence of a variable magnetic field. A pulsed arc system is used to perform preliminary experiments on the arc mobility for the different types of graphite for the selection of proper material morphology and the design of a continuous vacuum arc system. The characteristics of arc mobility, erosion rate, and carbon ion flux emitted from the continuous carbon source are then evaluated in view of particle-free diamond-like protective coatings. Results show that the arc spot velocity on graphite cathodes is larger on cathodes having larger grain size, lower electrical resistivity and higher apparent density. The spot velocity is also lower for cathodes having larger pore sizes and total porosity. The arc spot velocity is also found to be increased by increasing the magnetic field intensity over the surface of any graphite type. Reduced residence time of the spot on a given site of the cathode resulting from arc velocity increase should lead to a reduction in the heat load input in the cathode spot. This correlates with results on the number of emitted particles, the film thickness and roughness, and the erosion rate that are found to decrease, while the ion flux emission is increased. Diamond-like carbon (DLC) films free of particles are produced in a continuous arc ion plating (AIP) system. The ion energy in the continuous AIP system is found to vary with the graphite surface properties and the intensity of a plasma confining magnetic field in front of the cathode. The ion energies measured vary between 39.8 eV to 62.6 eV.

No description available.

We develop a coarse grained methodology to study solvent mediated interactions between two or more hydrophobic spheres. The free energy of a configuration of two hydrophobic hard spheres is calculated as a function of their separation to understand the thermodynamic force between them mediated by water. The range of the hydrophobic interaction is found to be of the order of the equilibrium correlation length of water; beyond this range the hydrophobicity induced force is negligible. We also examine the free energy landscape corresponding to the two interacting hydrophobic spheres, and find a new intermediate state between the two states of separate and non-interacting spheres and a weakly bound cluster. The nature of this intermediate state changes depending on the size of the spherical particles, and even disappears beyond a minimum critical radius. Our results are relevant to the understanding of hydrophobic mediated interactions in coarse grained models of protein folding and protein protein interactions which, to date, have only accounted for hydrophobicity in an empirical way.

Two methods for the estimation of non-esterified fatty acids in plasma were evaluated. An attempt was made to obtain a reliable micro-technique to estimate these acids in blood fractions. The titrimetric method of Trout et al. was satisfactory in the analyses of pure fatty acids and fatty acids added to serum. In the analyses of palmitic and stearic acid solutions, the mean values ranged from 95 to 115 percent of actual values. The mean recovery of palmitic acid added to a serum was 110 percent. The reproductibility of the method was fair in replicate analyses of three standard sera on two to four different days. The mean values determined for Serum A were 645, 653, 641, and 605; for Serum B, 587 and 587; and for Serum C, 565, 571 and 533 μEq per liter of serum. The colorimetric micro-method of Mendelsohn was also satisfactory in the analyses of pure fatty acids, fatty acids added to a serum, and a fatty acid as a component of standard lipid mixtures. In the analyses of palmitic, stearic, and oleic acid solutions, the mean values ranged from 97 to 118 percent of actual values. The recoveries of palmitic and oleic acids added to a serum ranged from 81 to 111 percent in four different experiments. In the determination of oleic acid from mixtures of several lipids, the recovery ranged from 95 to 107 percent. The reproductibility of the method was also fair in replicate analyses of a standard serum on 11 different days. The individual determinations ranged from 768 to 1046 μEq per liter of serum with a mean of 917. The mean values of 11 different experiments ranged from 830 to 1013 μEq per liter of serum. A comparison of methods was made by analyzing four standard sera in replicate by both methods. The values of the non-esterified fatty acids by the method of Mendelsohn were approximately twice those by the method of Trout et al. The difference was attributed to the degrees of extraction of non-esterified fatty acids and/or other acids from the serum by the two methods. The concentrations of the non-esterified fatty acids in the sera and the erythrocytes of 16 subjects of both sexes, ranging in age from 23 to 66 years, were determined by an adaptation of the colorimetric method of Mendelsohn. The concentrations in the sera ranged from 380 to 1057 μEq per liter with a mean of 800. The concentrations in the erythrocytes were consistently higher than those in the serum for all the subjects and ranged from 552 to 1919 μEq per liter with a mean of 1362. / Graduation date: 1965

Frankfurt (Main), University, Diss., 2007.

Universiẗat, Diss., 2006--Frankfurt (Main). / Zsfassung in dt. und engl. Sprache.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaf 131-).

Thesis (M.S.)--Ohio University, November, 1981. / Title from PDF t.p.

Thesis (doctoral)--Helsinki University of Technology, 2007. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph.D) University of Adelaide, Dept. of Mathematical Physics, 1967. / Typescript.