Transmission of power by belts

Thesis (BS)--University of Illinois, 1887MsBound with 10 other University of Illinois theses IU-

Characteristics of relativistic microburst intensity from SAMPEX observations

Relativistic electron microbursts are an important electron loss process from the radiation belts into the atmosphere. These precipitation events have been shown to significantly impact the radiation belt fluxes and atmospheric chemistry. In this study we address a lack of knowledge about the relativistic microburst intensity using measurements of 21,746 microbursts from the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX). We find that the relativistic microburst intensity increases as we move inward in L, with a higher proportion of low‐intensity microbursts (2,250 [MeV cm2 sr s]−1) in the 03–11 magnetic local time region increases as geomagnetic activity increases, consistent with changes in the whistler mode chorus wave activity. Comparisons between relativistic microburst properties and trapped fluxes suggest that the microburst intensities are not limited by the trapped flux present alongside the scattering processes. However, microburst activity appears to correspond to the changing trapped flux; more microbursts occur when the trapped fluxes are enhancing, suggesting that microbursts are linked to processes causing the increased trapped fluxes. Finally, modeling of the impact of a published microburst spectra on a flux tube shows that microbursts are capable of depleting <500‐keV electrons within 1 hr and depleting higher‐energy electrons in 1–23 hr

Thermoelectric properties of co-doped (Bi0.98In0.02)2Te2.7Se0.3 / reduced graphene oxide composites prepared by solid-state reaction

The thermoelectric properties of co-doped (Bi0.98In0.02)2Te2.7Se0.3/reduced graphene oxide composites between 10 - 325 K are presented. X-ray diffraction confirms that the composites adopt a rhombohedral structure with space group R3¯m. Field emission scanning electron microscopy reveals an interface structure of reduced graphene oxide (rGO). N-type conducting behaviour is observed for all the samples, as ascertained by Hall effect and Seebeck coefficient measurements, with a carrier concentration of 1025/m3. The thermal conductivity and electrical resistivity of (Bi0.98In0.02)2Te2.7Se0.3/0.02 wt% reduced graphene oxide composite is found to decrease by 1.6 and 10 times respectively in comparison with that of (Bi0.98In0.02)2Te2.7Se0.3. The power factor is enhanced by 7 times for (Bi0.98In0.02)2Te2.7Se0.3/0.01 wt% rGO compared to that of (Bi0.98In0.02)2Te2.7Se0.3

Generic flow profiles induced by a beating cilium

We describe a multipole expansion for the low Reynolds number fluid flows generated by a localized source embedded in a plane with a no-slip boundary condition. It contains 3 independent terms that fall quadratically with the distance and 6 terms that fall with the third power. Within this framework we discuss the flows induced by a beating cilium described in different ways: a small particle circling on an elliptical trajectory, a thin rod and a general ciliary beating pattern. We identify the flow modes present based on the symmetry properties of the ciliary beat.Comment: 12 pages, 6 figures, to appear in EPJ

Modeling of complex oxide materials from the first principles: systematic applications to vanadates RVO3 with distorted perovskite structure

"Realistic modeling" is a new direction of electronic structure calculations, where the main emphasis is made on the construction of some effective low-energy model entirely within a first-principle framework. Ideally, it is a model in form, but with all the parameters derived rigorously, on the basis of first-principles electronic structure calculations. The method is especially suit for transition-metal oxides and other strongly correlated systems, whose electronic and magnetic properties are predetermined by the behavior of some limited number of states located near the Fermi level. After reviewing general ideas of realistic modeling, we will illustrate abilities of this approach on the wide series of vanadates RVO3 (R= La, Ce, Pr, Nd, Sm, Gd, Tb, Yb, and Y) with distorted perovskite structure. Particular attention will be paid to computational tools, which can be used for microscopic analysis of different spin and orbital states in the partially filled t2g-band. We will explicitly show how the lifting of the orbital degeneracy by the monoclinic distortion stabilizes C-type antiferromagnetic (AFM) state, which can be further transformed to the G-type AFM state by changing the crystal distortion from monoclinic to orthorhombic one. Two microscopic mechanisms of such a stabilization, associated with the one-electron crystal field and electron correlation interactions, are discussed. The flexibility of the orbital degrees of freedom is analyzed in terms of the magnetic-state dependence of interatomic magnetic interactions.Comment: 23 pages, 13 figure

Slot Coating Minimum Film Thickness in Air and in Rarefied Helium

YesThis study assesses experimentally the role of gas viscosity in controlling the minimum film thickness in slot coating in both the slot over roll and tensioned web modes. The minimum film thickness here is defined with respect to the onset of air entrainment rather than rivulets, the reason being that rivulets are an extreme form of instabilities occurring at much higher speeds. The gas viscosity effects are simulated experimentally by encasing the coaters in a sealed gas chamber in which various gases can be admitted. An appropriate choice of two gases was used to compare performances: air at atmospheric pressure and helium at sub-ambient pressure (25mbar), which we establish has a significantly lower “thin film” viscosity than atmospheric air. A capacitance sensor was used to continuously measure the film thickness on the web, which was ramped up in speed at a fixed acceleration whilst visualizations of the film stability were recorded through a viewing port in the chamber. The data collected show clearly that by coating in rarefied helium rather that atmospheric air we can reduce the minimum film thickness or air/gas entrainment low-flow limit. We attribute this widening of the stable coating window to the enhancement of dynamic wetting that results when the thin film gas viscosity is reduced. These results have evident practical significance for slot coating, the coating method of choice in many new technological applications, but it is their fundamental merit which is new and one that should be followed with further data and theoretical underpinning

Population Modeling Highlights Drug Disposition Differences Between Tenofovir Alafenamide and Tenofovir Disoproxil Fumarate in the Blood and Semen

Understanding antiretroviral disposition in the male genital tract, a distinct viral compartment, can provide insight for the eradication of HIV. Population pharmacokinetic modeling was conducted to investigate the disposition of tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF), and emtricitabine and their metabolites in blood and semen. Blood plasma and seminal plasma (SP) concentrations of tenofovir and emtricitabine were measured, as were tenofovir-diphosphate and emtricitabine-triphosphate concentrations in peripheral blood mononuclear cells (PBMCs) and seminal mononuclear cells. Sequential compartmental modeling described drug disposition in blood and semen. Our modeling suggests slower elimination of apparent tenofovir-diphosphate PBMC and faster elimination of tenofovir SP after administration of TAF compared with TDF, likely reflecting flip-flop kinetics. Additionally, TAF metabolism to tenofovir appeared slower in semen compared with blood; however, SP elimination of TAF-derived tenofovir appeared faster than its blood plasma elimination. These findings provide valuable insight for further mechanistic study of cellular entry and drug metabolism in the male genital tract