Seismic Response of the Pile Foundation of Ohba-Ohashi Bridge

The paper outlines the recorded response to numerous earthquakes of the pile foundation, the supporting soil, and the superstructure of the main pier of a road bridge. The records include free-field accelerograms at the ground surface and the base of the alluvial deposit, accelerograms on the footing and the superstructure, and the bending and axial strain histories at several depths along two of the sixty-four piles. Recently developed methods of seismic analysis are used in interpreting the recorded data. Extensive comparisons are made between theory and measurements. Successes and failures of the theory are discussed. Emphasis is given to the distribution of seismic bending strains along the pile; the theoretically-anticipated concentration of such strains at an interface between two layers with sharply-differing soil stiffnesses is fully confirmed

Determination of the Major Impurity Radiators in the Reheat Mode Discharges in the Compact Helical System

Radiation brightness and impurity behaviors have been studied for reheat mode discharges in the Compact Helical System (CHS) by three different types of impurity diagnostics. Total radiation power measured by a pyroelectric detector significantly reduces after entering the reheat mode, whereas the line-averaged radiation brightness measured by an absolute extreme ultraviolet (AXUV) photodiode array increases especially for a center viewing chord due to the impurity accumulation in the plasma core. One possible reason for this opposite behavior between the two bolometric detectors is the reduced sensitivity of the AXUV photodiode for lower energy photons in vacuum ultraviolet (VUV) region. This speculation is supported by temporal evolutions of VUV spectra measured by a grazing incidence spectrometer. These results demonstrate that the comparison of three impurity diagnostics would be beneficial to the determination of the major impurity radiators and a comprehensive understanding of impurity behaviors in the reheat mode discharges

The LTE simulation on decaying arc plasmas in various arc quenching gases in a model circuit breaker

The present report describes numerical thermofluid simulation results of various gas arcs in a nozzle space at atmospheric pressure on the assumption of local thermodynamic equilibrium condition. It is crucial to investigate fundamentals on arc extinction phenomena by numerical simulation approach as well as experimental approach. The SF6, Ar, CO2 and N2 arcs in our experimental setup were treated for the present calculation because we can accurately control the voltage and arc current in our experimtants and we can perform accurate electron density measurements for fundamental investigation and comparison. Two-dimensional temperature distributions in various gas-blast arcs were calculated in a steady state at a direct current of 50 A. Furthermore, transient temperature distributions in these arcs were computed under free recovery condition. Then, we calculated transient responses under free recovery condition by using calculated results in the steady state. The calculated arc voltage in the steady state and the transition of electron density under free recovery condition were compared with those obtained by laser Thomson scattering method in our experiments. © 2015 IEEE

Evaluation on current interruption ability of CO2 and SF6 using current and voltage application highly controlled by power semiconductors

This paper reports a new simple test technique to evaluate current interruption ability of arc quenching gases. In the test, current and voltage applied to the arc was controlled using a insulated gate bipolar transistor (IGBT). Switching the IGBT enables us to produce free recovery conditions for a fundamental arc decay in nozzles. In addition to this, a voltage was intentionally applied to the free recovery arcs between the electrodes by switching-off IGBT again at the specified delay time td. This applied voltage is called quasi transient recovery voltage (quasi-TRV). We can evaluate successful interruption or interruption failure by measuring the current between the electrodes after quasi-TRV application. We compared the interruption ability of SF6 and CO2 through this developed technique. The experimental results show that a residual arc in SF6 gas flow decays four times more rapidly than that in CO2 gas flow. Influence of observation holes in the nozzles used in the experiments was also investigated, showing less influence of observation on the arc behavior. © 2015 IEEE

Nonlinear Excitation of Subcritical Instabilities in a Toroidal Plasma

In a collisionless plasma, it is known that linearly stable modes can be destabilized (subcritically) by the presence of structures in phase space. However, nonlinear growth requires the presence of a seed structure with a relatively large threshold in amplitude. We demonstrate that, in the presence of another, linearly unstable (supercritical) mode, wave-wave coupling can provide a seed, which is significantly below the threshold, but can still grow by (and only by) the collaboration of fluid and kinetic nonlinearities. By modeling the subcritical mode kinetically, and the impact of the supercritical mode by simple wave-wave coupling equations, it is shown that this new kind of subcritical instability can be triggered, even when the frequency of the supercritical mode is rapidly sweeping. The model is applied to the bursty onset of geodesic acoustic modes in a LHD experiment. The model recovers several key features such as relative amplitude, time scales, and phase relations. It suggests that the strongest bursts are subcritical instabilities, driven by this mechanism of combined fluid and kinetic nonlinearities

Characterization of the novel mutant A78T-HERG from a long QT syndrome type 2 patient: Instability of the mutant protein and stabilization by heat shock factor 1

Background:The human ether-a-go-go-related gene (HERG) encodes the α-subunit of rapidly activating delayed-rectifier potassium channels. Mutations in this gene cause long QT syndrome type 2 (LQT2). In most cases, mutations reduce the stability of the channel protein, which can be restored by heat shock (HS). Methods: We identified the novel mutant A78T-HERG in a patient with LQT2. The purpose of the current study was to characterize this mutant protein and test whether HS and heat shock factors (HSFs) could stabilize the mutant protein. A78T-HERG and wild-type HERG (WT-HERG) were expressed in HEK293 cells and analyzed by immunoblotting, immunoprecipitation, immunofluorescence, and whole-cell patch clamping. Results: When expressed in HEK293 cells, WT-HERG gave rise to immature and mature forms of the protein at 135 and 155 kDa, respectively. A78T-HERG gave rise only to the immature form, which was heavily ubiquitinated. The proteasome inhibitor MG132 increased the expression of immature A78T-HERG and increased both the immature and mature forms of WT-HERG. WT-HERG, but not A78T-HERG, was expressed on the plasma membrane. In whole-cell patch clamping experiments, depolarizing pulses evoked E4031-sensitive HERG channel currents in cells transfected with WT-HERG, but not in cells transfected with A78T-HERG. The A78V mutant, but not A78G mutant, remained in the immature form similarly to A78T. Maturation of the A78T-HERG protein was facilitated by HS, expression of HSF-1, or exposure to geranyl geranyl acetone. Conclusions: A78T-HERG was characterized by protein instability and reduced expression on the plasma membrane. The stability of the mutant was partially restored by HSF-1, indicating that HSF-1 is a target for the treatment for LQT2 caused by the A78T mutation in HERG

Response of plasma toroidal flow to the transition between nested and stochastic magnetic field in LHD

Response of the plasma toroidal flow to the forward and backward transition between the nested and the stochastic magnetic field is studied using the charge exchange spectroscopy in the large helical device (LHD). Abrupt damping of toroidal flow associated with a transition from nested magnetic flux surface to a stochastic magnetic field is observed when the magnetic shear at the rational surface decreases to 0.5 after the exchange of the neutral beam injection (NBI) direction from co- to counter-direction in LHD. The stochastization of magnetic field occurs only in a narrow range of magnetic shear near 0.5 and spontaneousback-transition from stochastic to nested magnetic field (healing) is observed in the steady-state phase of magnetic shear. When the NBI direction is changed from counter- to co-direction, the healing of magnetic field occurs associated with the increase of magnetic shear