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2000

Articles 1 - 11 of 11

Full-Text Articles in Physics

Thermal Lattice Boltzmann Simulation For Multispecies Fluid Equilibration, Linda L. Vahala, Darren Wah, George Vahala, Jonathan Carter, Pavol Pavlo Jul 2000

Thermal Lattice Boltzmann Simulation For Multispecies Fluid Equilibration, Linda L. Vahala, Darren Wah, George Vahala, Jonathan Carter, Pavol Pavlo

Electrical & Computer Engineering Faculty Publications

The equilibration rate for multispecies fluids is examined using thermal lattice Boltzmann simulations. Two-dimensional free-decay simulations are performed for effects of velocity shear layer turbulence on sharp temperature profiles. In particular, parameters are so chosen that the lighter species is turbulent while the heavier species is laminar-and so its vorticity layers would simply decay and diffuse in time. With species coupling, however, there is velocity equilibration followed by the final relaxation to one large co- and one large counter-rotating vortex. The temperature equilibration proceeds on a slower time scale and is in good agreement with the theoretical order of magnitude …

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Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell May 2000

Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell

Electrical and Computer Engineering Faculty Publications

The ring synthetic discriminant function (RSDF) filter for rotation-invariant response is discussed for pattern recognition. This method uses one half of a slice of the Fourier transform of the object to generate the transfer function of the filter. This is accomplished by rotating the one half of a slice in the Fourier domain through 2π rad about the zero-frequency point of the Fourier plane. This filter has the advantage of always matching at least one half of a slice of the Fourier transform of any rotation of the image. An analytical discussion of the filter construction and correlation results are …

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A High Energy X-Ray And Neutron Scattering Study Of Iron Phosphate Glasses Containing Uranium, Mevlüt Karabulut, G. K. Marasinghe, C. S. Ray, Y. S. Badyal, M.-L. Saboungi, S. Shastri, D. Haeffner, George Daniel Waddill, D. E. Day Mar 2000

A High Energy X-Ray And Neutron Scattering Study Of Iron Phosphate Glasses Containing Uranium, Mevlüt Karabulut, G. K. Marasinghe, C. S. Ray, Y. S. Badyal, M.-L. Saboungi, S. Shastri, D. Haeffner, George Daniel Waddill, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

The atomic structure of iron phosphate glasses containing uranium has been studied by complementary neutron and x-ray scattering techniques. by combining x-ray and neutron structure factors, detailed information about different pair interactions has been obtained. Most of the basic structural features such as coordination numbers and O-O and P-O distances in uranium containing glasses are the same as those in the base glass of batch composition 40Fe2O3-60P2O5 (mol %). However, the Fe-O distances change slightly with the addition of uranium. The observed structural parameters support a structural model in which the waste elements occupy voids in the Fe-O-P network, hence, …

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Nonlinear Self-Organization In Photorefractive Materials, Partha P. Banerjee, Nickolai Kukhtarev, John O. Dimmock Jan 2000

Nonlinear Self-Organization In Photorefractive Materials, Partha P. Banerjee, Nickolai Kukhtarev, John O. Dimmock

Electrical and Computer Engineering Faculty Publications

This chapter discusses self-organization and its effects in optics. One of the most exciting and potentially useful areas of current research in optics involves the understanding and exploitation of self-organization in nonlinear optical systems. This self-organization may sometimes lead to the evolution of complex spatial patterns that can be regarded as the nonlinear eigenmodes of the system. Generation of these patterns is characteristically marked by the presence of intensity thresholds. In a nonlinear system with complicated temporal dynamics, it turns out that one cannot retain purity in spatial dimensionality. It is therefore equally important to investigate the dynamics of the …

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Series Operation Of Direct Current Xenon Chloride Excimer Sources, Ahmed El-Habachi, Wenhui Shi, Mohamed Moselhy, Robert H. Stark, Karl H. Schoenbach Jan 2000

Series Operation Of Direct Current Xenon Chloride Excimer Sources, Ahmed El-Habachi, Wenhui Shi, Mohamed Moselhy, Robert H. Stark, Karl H. Schoenbach

Bioelectrics Publications

Stable, direct current microhollow cathode discharges in mixtures of hydrochloric acid, hydrogen, xenon, and neon have been generated in a pressure range of 200–1150 Torr. The cathode hole diameter was 250 μm. Sustaining voltages range from 180 to 250 V at current levels of up to 5 mA. The discharges are strong sources of xenon chloride excimer emission at a wavelength of 308 nm. Internal efficiencies of approximately 3% have been reached at a pressure of 1050 Torr. The spectral radiant power at this pressure was measured as 5 mW/nm at 308 nm for a 3 mA discharge. By using …

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Quantitative Analysis Of Ultra-Fine Goethite In Rust Layer On Steel Using Mossbauer And X-Ray Diffraction Spectroscopy, Masato Yamashita, Toshihei Misawa, H. E. Townsend, D. C. Cook Jan 2000

Quantitative Analysis Of Ultra-Fine Goethite In Rust Layer On Steel Using Mossbauer And X-Ray Diffraction Spectroscopy, Masato Yamashita, Toshihei Misawa, H. E. Townsend, D. C. Cook

Physics Faculty Publications

We have proposed determination procedure of the relative amounts of rust constituents of steel. Mossbauer spectroscopy provides the relative amounts of crystalline rust constituents including ultra-fine crystals. A quantitative analysis of ultra-fine crystals is possible with the resolution of several percent by comparing the Mossbauer results with the relative amounts of rust constituents determined by X-ray diffraction spectroscopy.

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Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt Jan 2000

Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt

Articles

The three-dimensional Row in a corner of fixed angle α induced by the rotation in its plane of one of the boundaries is considered. A local similarity solution valid in a neighbourhood of the centre of rotation is obtained and the streamlines are shown to be closed curves. The effects of inertia are considered and are shown to be significant in a small neighbourhood of the plane of symmetry of the flow. A simple experiment confirms that the streamlines are indeed nearly closed; their projections on planes normal to the line of intersection of the boundaries are precisely the 'Taylor' …

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Local Environment Of Iron And Uranium Ions In Vitrified Iron Phosphate Glasses Studied By Fe K And Uliii-Edge X-Ray Absorption Fine Structure Spectroscopy, Mevlüt Karabulut, G. K. Marasinghe, C. S. Ray, D. E. Day, George Daniel Waddill, P. G. Allen, C. H. Booth, J. J. Bucher, D. L. Caulder, D. K. Shuh, M. Grimsditch, M.-L. Saboungi Jan 2000

Local Environment Of Iron And Uranium Ions In Vitrified Iron Phosphate Glasses Studied By Fe K And Uliii-Edge X-Ray Absorption Fine Structure Spectroscopy, Mevlüt Karabulut, G. K. Marasinghe, C. S. Ray, D. E. Day, George Daniel Waddill, P. G. Allen, C. H. Booth, J. J. Bucher, D. L. Caulder, D. K. Shuh, M. Grimsditch, M.-L. Saboungi

Materials Science and Engineering Faculty Research & Creative Works

The local structure of iron and uranium ions in a series of iron phosphate glasses with the general composition (40 - x)Fe2O3-xUO2-60P2O5 and (1-x-y)(40Fe2O3-60P2O5)-xUO2-y(Na2O or CaO) was investigated using Fe K-edge and U LIII-edge x-ray absorption fine structure spectroscopy. Replacing Fe2O3 by UO2 in the glass caused more distortion in the coordination environment of Fe(III) ions. Extended x-ray absorption fine structure fits revealed that the Fe-P bonds observed in the base glass also …

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New Free-Space Multistage Optical Interconnection Network And Its Matrix Theory, Fengguang Luo, Mingcui Cao, Anjun Wan, Jun Xu, Xinjun Zhou, Cong Deng Jan 2000

New Free-Space Multistage Optical Interconnection Network And Its Matrix Theory, Fengguang Luo, Mingcui Cao, Anjun Wan, Jun Xu, Xinjun Zhou, Cong Deng

Electro-Optics and Photonics Faculty Publications

A new free-space multistage optical interconnection network which is called the Comega interconnection network is presented. It has the same topological construction for the cascade stages of the Comega interconnection. The concept of the left Comega and the right Comega interconnection networks are given to describe the whole Comega interconnection network. The matrix theory for the Comega interconnection network is presented. The route controlling of the Comega interconnection network is decided based on the matrix analysis. The node switching states in cascade stages of the 8 by 8 Comega interconnection network for the route selection are given. The data communications …

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Textured Mos 2 Thin Films Obtained On Tungsten: Electrical Properties Of The W/Mos 2 Contact, E. Gourmelon, J. C. Bernède, J. Pouzet, S. Marsillac Jan 2000

Textured Mos 2 Thin Films Obtained On Tungsten: Electrical Properties Of The W/Mos 2 Contact, E. Gourmelon, J. C. Bernède, J. Pouzet, S. Marsillac

Electrical & Computer Engineering Faculty Publications

Textured films of molybdenum disulfide have been obtained by solid state reaction between the constituents in thin films form when a (200) oriented tungsten sheet is used as substrate. The crystallites have their c axis perpendicular to the plane of the substrate. The annealing conditions are T=1073K and t=30 min. The films are stoichoimetric and p type. Such highly textured films are achieved without foreign atom addition (Ni, Co...). It appears, as shown by x-ray photoelectron spectroscopy, that a thin WS2 layer is present at the interface W/MoS2. The crystallization process is discussed by a …

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Characterization Of Poly-Si Thin Films Deposited By Magnetron Sputtering Onto Ni Prelayers, Elena A. Guliants, Wayne A. Anderson Jan 2000

Characterization Of Poly-Si Thin Films Deposited By Magnetron Sputtering Onto Ni Prelayers, Elena A. Guliants, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

A method of producing a polycrystalline silicon thin film on a foreign substrate without subsequent annealing has been developed. Thermally evaporated 5–100 nm thick Nifilms served as prelayers for magnetron sputtered Si thin films. A continuous film was obtained as a result of metal induced growth of polysilicon during low temperature (below 600 °C) deposition. The film uniformity is promising for large area device applications. The influence of the Ni prelayer thickness on the grain size of thus obtained films was investigated. Atomic force microscopy and cross-sectional scanning electron microscopy studies revealed features in the 150–600 nm size range while …

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