Thesis (doctoral)--Rijksuniversiteit te Utrecht, 1946. / Includes bibliographical references.

A sensitive, wide or narrow band, solid state spectrometer operating at a wavelength of 0.85 cm has been built which is described in detail. The spectrometer is of the crystal detector reflection-cavity-in-magic-Tee-bridge type and can operate from room down to liquid helium temperatures. The cavity Is excited In the TE₁₁₁ mode and the magnetic field modulated at 140 cps. Both large and small field modulations are incorporated for scope presentation of line width varying from about 0.5 to 500 gauss. Signals from single crystals of copper sulphate pentahydrate and polycrystalline 1-1-diphenyl-2-picryl hydrazyl (DPPH) have been obtained. From the latter, a sensitivity limit of about 10⁻⁸ gram is obtained at room temperature for a bandwidth of 1 cps indicating a sensitivity of the order of 10⁻¹¹ gram at 4.2° K. Various methods of improvement were discussed in order to reach the ultimate sensitivity. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A light-scattering method has been utilized to determine the seasonal and geographical variation of optical turbidity in the waters of the major inlets of the southern British Columbia coast. (The optical turbidity is here defined as the fractional decrease in light intensity per meter due to the presence of suspended material in the water.) The major contribution to the turbidity in the inlets is the minerogenic material brought into the inlet by rivers at or near the head. The inlets whose rivers are primarily glacier-fed possess the highest turbidity values and exhibit the most marked seasonal variation of turbidity. The net outflow of water in the shallow layers-which is a prominent feature of the circulation in the inlets-is the basic mechanism by which the material introduced by rivers is distributed throughout the length of the inlet. The surface values of turbidity range from about 0.5 to over 30 meters⁻¹ (m⁻¹) in the summer and from about 0.1 to 1 m⁻¹ in the winter. The values decrease from head to mouth, the effect being especially marked in the summer. The main body of water in the inlets usually possesses uniform turbidity at any time of the year, values ranging from 0.1 to 0.7 m⁻¹. A marked increase in turbidity occurs, in the bottom layers of water, in all inlets. In the shallower inlets, this increase appears to be due primarily to tidal scouring of bottom material. In the deep inlets, it is presumably due to two causes: intermittent intrusion of deep water from outside the inlet, and, to a more prominent degree, turbidity currents originating at the inlet head. Evidence suggests that these currents are slow and possess a frequency of occurrence of the order of weeks. The contribution of material of biological origin to the turbidity is confined primarily to the inlets with small runoff. Little or no dissolved coloured matter is present in inlet waters. Size analysis by microscope indicates that the suspended material averages somewhat below 10μ in the major portion of an inlet; average sizes of up to 17μ occur near the head of inlets during large runoff. There is little material below 1μ in size. Light-scattering measurements indicate that the suspended material is preponderantly anisotropic in nature. The concentration of material varies from less than 1 to over 100 parts per million by volume. By means of the turbidity and concentration values obtained, it has been estimated that the rate of sedimentation in the inlets ranges from about 35 cms to about 650 cms per 100 years, the value increasing from mouth to head of the inlet. The following relation between the Secchi disc reading D and the average turbidity T over the distance D has been found: T = 1.8/D(1.2) / Science, Faculty of / Physics and Astronomy, Department of / Graduate

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Approved for public release; distribution is unlimited / The significance of the Radar Cross Section (RCS) in the outcome of military engagements makes its prediction an important problem in modern Electronic Warfare. The POFACETS program, previously developed at the Naval Postgraduate School (NPS), uses the Physical Optics method to predict the RCS of complex targets, which are modeled with the use of triangular facets. The program has minimum computer resource requirements and provides convenient run-times. This thesis upgraded, enhanced and expanded the functionalities and capabilities of the POFACETS program. The new functionalities were implemented by upgrading the Graphical User Interface and model database, allowing the creation of models with an unlimited number of facets, providing capabilities for the automatic creation of models with standard geometric shapes, allowing the combination of existing target models, providing capabilities for sharing target models with commercial CAD programs, and creating new display formats for RCS results. The new computational capabilities include the development of a user- updateable database of materials and coatings that can be applied to models in one or multiple layers, and the computation of their effects on the models' RCS. Also implemented are the computations of the ground's effect on the RCS, and the exploitation of symmetry planes in models, in order to decrease run-time for RCS prediction. / Major, Hellenic Air Force

Thesis (M.S. in Systems Engineering and M.S. in Electrical Engineering)--Naval Postgraduate School, Sept. 2004. / Thesis advisor(s): David C. Jenn, D. Curtis Schleher. Includes bibliographical references (p. 125). Also available online.

Thesis (Ph. D.)--University of Iowa, 1923. / Reprinted from the Journal of the Optical society of America and review of scientific instruments, v. 10, no. 6, June, 1925.

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