Rigid Structure Response Analysis to Seismic and Blast Induced Ground Motions

AbstractComprehensive studies of rigid structure responses to seismic ground excitations have been reported. It was found that the rocking and sliding response of a rigid structure is highly nonlinear. The structure stability depends on the structure slenderness, as well as the ground motion amplitude, frequency and duration. Compared to an earthquake ground motion, ground shock induced by underground or surface explosion has very large amplitude, high frequency and short duration. Moreover, vertical component of a ground shock may be substantially larger than the gravitational acceleration g. This will cause the unanchored rigid structure jump or fly into air. Therefore, the responses and stability regions of a rigid structure to blast induced ground shock will be very different from those under seismic ground motions. No study of rigid structure response to ground shock of amplitude more than 1.0g can be found in the literature. As there might be many rigid structures such as computers, document shelfs, and other important equipments in a building or a military command center close to an explosion center, understanding rigid structure response to ground shock is essential for protection of such equipments. In this study, theoretical derivation and numerical prediction of rigid structure response to ground shock are carried out. Numerical results of stability regions of rigid structures to ground shock are derived. Particular attentions are paid to the case when the vertical ground shock is more than 1.0g and the rigid structure flies into the air. Results are compared to those obtained with earthquake ground motions. Discussions on the rigid structure stability to earthquake motion and ground shock are made

Negative Electron-electron Drag Between Narrow Quantum Hall Channels

Momentum transfer due to Coulomb interaction between two parallel, two-dimensional, narrow, and spatially separated layers, when a current I_{drive} is driven through one layer, is studied in the presence of a perpendicular magnetic field B. The current induced in the drag layer, I_{drag}, is evaluated self-consistently with I_{drive} as a parameter. I_{drag} can be positive or negative depending on the value of the filling factor \nu of the highest occupied bulk Landau level (LL). For a fully occupied LL, I_{drag} is negative, i.e., it flows opposite to I_{drive}, whereas it is positive for a half-filled LL. When the circuit is opened in the drag layer, a voltage \Delta V_{drag} develops in it; it is negative for a half-filled LL and positive for a fully occupied LL. This positive \Delta V_{drag}, expressing a negative Coulomb drag, results from energetically favored near-edge inter-LL transitions that occur when the highest occupied bulk LL and the LL just above it become degenerate.Comment: Text file in Latex/Revtex/preprint format, 7 separate PS figures, Physical Review B, in pres

Coulomb Drag Between Parallel Ballistic Quantum Wires

The Coulomb drag between parallel, {\it ballistic} quantum wires is studied theoretically in the presence of a perpendicular magnetic field B. The transresistance R_D shows peaks as a function of the Fermi level and splitting energy between the 1D subbands of the wires. The sharpest peaks appear when the Fermi level crosses the subband extrema so that the Fermi momenta are small. Two other kinds of peaks appear when either {\it intra}- or {\it inter}-subband transitions of electrons have maximum probability; the {\it intra}-subband transitions correspond to a small splitting energy. R_D depends on the field B in a nonmonotonic fashion: it decreases with B, as a result of the suppression of backscattering, and increases sharply when the Fermi level approaches the subband bottoms and the suppression is outbalanced by the increase of the Coulomb matrix elements and of the density of states.Comment: Text 14 pages in Latex/Revtex format, 4 Postscript figures. Phys. Rev. B,in pres

Lack of CD8+ T-cell co-localization with Kaposi’s sarcoma- associated herpesvirus infected cells in Kaposi’s sarcoma tumors

Despite the close association between Kaposi’s sarcoma (KS) and immune dysfunction, it remains unclear whether tumor infiltrating immune cells (TIIC), by their absence, presence, or dysfunction, are mechanistically correlated with KS pathogenesis. Therefore, their potential capacity to serve as prognostic biomarkers of KS disease progression or control is unclear. Because epidemic-KS (EpKS) occurs with HIV-1 co-infection, it is particularly important to compare TIIC between EpKS and HIV-negative African endemic-KS (EnKS) to dissect the roles of HIV-1 and Kaposi Sarcoma-associated herpesvirus (KSHV) in KS pathogenesis. This cross-sectional study of 13 advanced KS (4 EnKS, 9 EpKS) patients and 3 healthy controls utilized single-color immunohistochemistry and dual-color immunofluorescence assays to characterize and quantify KSHV infected cells in relation to various TIIC in KS biopsies. Analysis of variance (ANOVA) and Mann-Whitney tests were used to assess differences between groups where P-values \u3c 0.05 were considered significant. The abundance of KSHV infected cells was heterogeneous in KS biopsies. Despite the presence of T-cell chemoattractant chemokine CxCL-9 in biopsies, CD8+ T-cells were sparsely distributed in regions with evident KSHV infected cells but were readily detectable in regions devoid of KSHV infected cells (P \u3c 0.0001). CD68+ (M1) macrophages were evenly and diffusely distributed in KS biopsies, whereas, the majority of CD163+ (M2) macrophages were localized in regions devoid of KSHV infected cells (P \u3c 0.0001). Overall, the poor immune cell infiltration or co-localization in KS biopsies independent of HIV-1 co-infection suggests a fundamental tumor immune evasion mechanism that warrants further investigation

Analysis of pultrusion processing for long fiber reinforced thermoplastic composite system

Pultrusion is one of the composite processing technology, commonly recognized as a simple and cost-effective means for the manufacturing of fiber-reinforced, resin matrix composite parts with different regular geometries. Previously, because the majority of the pultruded composite parts were made of thermosetting resin matrix, emphasis of the analysis on the process has been on the conservation of energy from various sources, such as heat conduction and the curing kinetics of the resin system. Analysis on the flow aspect of the process was almost absent in the literature for thermosetting process. With the increasing uses of thermoplastic materials, it is desirable to obtain the detailed velocity and pressure profiles inside the pultrusion die. Using a modified Darcy's law for flow through porous media, closed form analytical solutions for the velocity and pressure distributions inside the pultrusion die are obtained for the first time. This enables us to estimate the magnitude of viscous dissipation and it's effects on the pultruded parts. Pulling forces refined in the pultrusion processing are also analyzed. The analytical model derived in this study can be used to advance our knowledge and control of the pultrusion process for fiber reinforced thermoplastic composite parts

Software fault-tolerance by design diversity DEDIX: A tool for experiments

The use of multiple versions of a computer program, independently designed from a common specification, to reduce the effects of an error is discussed. If these versions are designed by independent programming teams, it is expected that a fault in one version will not have the same behavior as any fault in the other versions. Since the errors in the output of the versions are different and uncorrelated, it is possible to run the versions concurrently, cross-check their results at prespecified points, and mask errors. A DEsign DIversity eXperiments (DEDIX) testbed was implemented to study the influence of common mode errors which can result in a failure of the entire system. The layered design of DEDIX and its decision algorithm are described

The relative importance of head, flux, and prior information in hydraulic tomography analysis

Using cross-correlation analysis, we demonstrate that flux measurements at observation locations during hydraulic tomography (HT) surveys carry nonredundant information about heterogeneity that are complementary to head measurements at the same locations. We then hypothesize that a joint interpretation of head and flux data, even when the same observation network as head has been used, can enhance the resolution of HT estimates. Subsequently, we use numerical experiments to test this hypothesis and investigate the impact of flux conditioning and prior information (such as correlation lengths and initial mean models (i.e., uniform mean or distributed means)) on the HT estimates of a nonstationary, layered medium. We find that the addition of flux conditioning to HT analysis improves the estimates in all of the prior models tested. While prior information on geologic structures could be useful, its influence on the estimates reduces as more nonredundant data (i.e., flux) are used in the HT analysis. Lastly, recommendations for conducting HT surveys and analysis are presented

Economical (k,m)-threshold controlled quantum teleportation

We study a (k,m)-threshold controlling scheme for controlled quantum teleportation. A standard polynomial coding over GF(p) with prime p > m-1 needs to distribute a d-dimensional qudit with d >= p to each controller for this purpose. We propose a scheme using m qubits (two-dimensional qudits) for the controllers' portion, following a discussion on the benefit of a quantum control in comparison to a classical control of a quantum teleportation.Comment: 11 pages, 2 figures, v2: minor revision, discussions improved, an equation corrected in procedure (A) of section 4.3, v3: major revision, protocols extended, citations added, v4: minor grammatical revision, v5: minor revision, discussions extende

The Quantum Hall Effect in Drag: Inter-layer Friction in Strong Magnetic Fields

We study the Coulomb drag between two spatially separated electron systems in a strong magnetic field, one of which exhibits the quantum Hall effect. At a fixed temperature, the drag mimics the behavior of $\sigma_{xx}$ in the quantum Hall system, in that it is sharply peaked near the transitions between neighboring plateaux. We assess the impact of critical fluctuations near the transitions, and find that the low temperature behavior of the drag measures an exponent $\eta$ that characterizes anomalous low frequency dissipation; the latter is believed to be present following the work of Chalker.Comment: 13 pages, Revtex 2.0, 1 figure upon request, P-93-11-09