Physical Sciences and Mathematics Commons^™

Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt, Scott Whittenburg

Chemistry Faculty Publications

The effects of the applied field, cell size, and cutting area on the ‘‘seed’’ induced magnetic reversal of a cobalt element array have been studied by a stochastic dynamic micromagnetics code using the Laudau–Lifshitz–Gilbert equation. Three magnetic reversal mechanisms under different magnitudes of the applied field have been investigated by examining the energy profiles. To minimize the effect of the thermal fluctuations on the switching time, an applied field with magnitude around 0.7 or 0.8 T and an element array with cutting area less than 10 nm310 nm are required. By using the smaller cellsize, the switching time and the …

Ubitour: A 3g/Wlan Architecture To Support E-Tourism, Vivek Chinta

University of New Orleans Theses and Dissertations

Electronic tourism is a new type of application that provides information, often location-based, to tourists. The information includes route guidance, listings of nearby points of interest, guided tours with multimedia presentations and experiences shared by visitors. E-tourism applications can also include storing sound and images recorded by visitors. An architecture to support e-tourism called 'UbiTour' is presented in this dissertation. UbiTour provides different services to visitors such as location-based information, route-guidance, announcements and visitor collaboration.

UbiTour aims at using 3G for ubiquitous connectivity and WLAN for high-speed, local information, running on a PDA. WLAN, specifically 802.11, provides a high-bandwidth, broadcast-based …

Thickness Dependence Of Magnetic Blocking In Granular Thin Films, Scott Whittenburg

Chemistry Faculty Publications

Interparticle interaction among single domain nanosize magnetic particles embedded in nonmagnetic matrix was studied. Attention was paid to concentrated Cu–Co granular thin films with a fixed magnetic volume fraction 20%. By analyzing theoretical models and comparing with experimental results, a dimensional constraint on the magnetic properties was found. As the film thickness reduces toward the thin limit the interparticle interaction plays important roles in modifying the magnetic behavior. The dipolar interaction energy was calculated among magnetic particles including far-neighbor interaction for films with different thickness values. When magnetization variation is included in the calculation, the resulting calculated interaction energy versus …

Dielectric Constant And Proton Order And Disorder In Ice Ih: Monte Carlo Computer Simulations, Steven W. Rick

Chemistry Faculty Publications

The dielectric properties of ice Ih are studied using a Monte Carlo algorithm for sampling over proton configurations. The algorithm makes possible the calculation of the dielectric constant and other properties of the proton-disordered crystal. Results are presented for three classical models of water, two commonly used nonpolarizable models (SPC/E and TIP4P) and a polarizable model
(TIP4P-FQ).

Optimal Beam Splitters For The Division-Of-Amplitude Photopolarimeter, R. M.A. Azzam, A. De

Electrical Engineering Faculty Publications

Optimal optical parameters of the beam splitter that is used in the division-of-amplitude photopolarimeter are determined. These are (1) 50%–50% split ratio of the all-dielectric beam splitter, (2) differential phase shifts in reflection and transmission Δ_r and Δ_t that differ by ±π/2, and (3) ellipsometric parameters (ψ_r, ψ_t)= (27.368°, 62.632°) or (62.632°, 27.368°). It is also shown that for any nonabsorbing beam splitter that splits incident unpolarized light equally, the relationship ψ_r+ψ_t=π/2 is always satisfied.

Finite Element Solutions Of Heat Transfer In Molten Polymer Flow In Tubes With Viscous Dissipation, Dongming Wei, Haibiao Luo

Mathematics Faculty Publications

This paper presents the results of finite element analysis of a heat transfer problem of flowing polymer melts in a tube with constant ambient temperature. The rheological behavior of the melt is described by a temperature dependent power-law model. Aviscous dissipation term is included in the energy equation. Temperature profiles are obtained for different tube lengths and different entrance temperatures. The results are compared with some similar results in the literature.

Ultrafine Nife2o4 Powder Fabricated From Reverse Microemulsion Process, Jiye Fang, Narayan Shama, Le Duc Tung, Eun Young Shin, Charles J. O'Connor, Kevin L. Stokes, Gabriel Caruntu, John B. Wiley, Leonard Spinu, Jinke Tang

Physics Faculty Publications

NiFe2O4 ultrafine powder with high crystallinity has been prepared through a reverse microemulsion route. The composition in starting solution was optimized, and the resulting NiFe2O4 was formed at temperature of around 550–600 °C, which is much lower than that observed from the solid-state reaction. Magnetic investigation indicates that samples are soft-magnetic materials with low coercivity and with the saturation magnetization close to the bulk value of Ni ferrite.

Self-Assembly Of Fept Nanoparticles Into Nanorings, Weilie L. Zhou, Jibao He, Jiye Fang, Tuyet-Anh Huynh, Trevor J. Kennedy, Kevin L. Stokes, Charles J. O'Connor

Physics Faculty Publications

The application of nanoparticles as quantum dots in nanoelectronics demands their arrangement in ordered arrays. Shape controlled self-assembly is a challenge due to the difficulties of obtaining proper self-assembling parameters, such as solvent concentration, organic ligands, and nanoparticle size. In this article, hard magnetic FePt nanoparticles were synthesized using a combination approach of reduction and thermal decomposition. The nanoparticles are about 4.5 nm and appeared as truncated octahedral enclosed by the

{100} and {111}

crystal facets of fcc structure. The nanoparticles are of hexagonal close packing and orient randomly in the self-assembly nanoarrays. By diluting the solution for large-area self-assembly, …

Mim And Nonlinear Least-Squares Inversions Of Aem Data In Barataria Basin, Louisiana, Melissa Whitten Bryan, Kenneth W. Holladay, Clyde J. Bergeron Jr., Juliette W. Ioup, George E. Ioup

Physics Faculty Publications

An airborne electromagnetic survey was performed over the marsh and estuarine waters of the Barataria basin of Louisiana. Two inversion methods were applied to the measured data to calculate layer thicknesses and conductivities: the modified image method (MIM) and a nonlinear least-squares method of inversion using two two-layer forward models and one three-layer forward model, with results generally in good agreement. Uniform horizontal water layers in the near-shore Gulf of Mexico with the fresher (less saline, less conductive) water above the saltier (more saline, more conductive) water can be seen clearly. More complex near-surface layering showing decreasing salinity/conductivity with depth …

Kerr-Resonance-Condition-Coupled Enhancement In Magneto-Optic Media, A. De, A. Puri

Physics Faculty Publications

We derive an expression for cyclotron frequency ω_c, which sets Re[ϵ₊ϵ₋]=1 in a magneto-optic (MO) substrate, at any incident photon energy. Thereby, at any desired part of the optical spectrum, large Kerr effects can be obtained, which are generally known to occur either at the free-charge-carrier-plasma-resonance frequency ω_p, or at frequencies where active electronic transitions take place. Under these conditions, ω_p is seen to play a very different role; it is seen that for any ω, the magnitude of the Kerr resonance in a single MO (InSb here) substrate increases …