Pressure Drop Across Woven Screens Under Uniform and Nonuniform Flow Conditions

Tests were conducted to determine the experimental pressure drop and velocity data for water flowing through woven screens. The types of materials used are dutch twill and square weave fabrics. Pressure drop measures were made at four locations in a rectangular channel. The data are presented as change in pressure compared with the average entry velocity and the numerical relationship is determined by dividing the volumetric flow rate by the screen area open to flow. The equations of continuity and momentum are presented. A computer program listing an extension of a theoretical model and data from that computer program are included

Comparison of the Methods for the Background Reduction of Thick Targets in Routine PIXE Analysis

開始ページ、終了ページ: 冊子体のページ付

Chemical Effects of L X-Ray Intensity Ratios in Niobium and Molybdenum Compounds by Elecron and Proton Bombardments

開始ページ、終了ページ: 冊子体のページ付

Electron (positron) beam polarization by Compton scattering on circularly polarized laser photons

In a number of papers an attractive method of laser polarization of electrons (positrons) at storage rings or linear colliders has been proposed. We show that these suggestions are incorrect and based on errors in simulation of multiple Compton scattering and in calculation of the Compton spin-flip cross sections. We argue that the equilibrium polarization in this method is zero.Comment: 11 pages, LaTeX, talk at 9-th Intern. Workshop on Linear Colliders (LC02), Feb. 4-8, 2002, SLAC, Stanford, US

Photon generation by laser-Compton scattering at the KEK-ATF

We performed a photon generation experiment by laser-Compton scattering at the KEK-ATF, aiming to develop a Compton based polarized positron source for linear colliders. In the experiment, laser pulses with a 357 MHz repetition rate were accumulated and their power was enhanced by up to 250 times in the Fabry-Perot optical resonant cavity. We succeeded in synchronizing the laser pulses and colliding them with the 1.3 GeV electron beam in the ATF ring while maintaining the laser pulse accumulation in the cavity. As a result, we observed 26.0 +/- 0.1 photons per electron-laser pulse crossing, which corresponds to a yield of 10^8 photons in a second.Comment: 3 pages, 5 figures, Preprint submitted to TIPP09 Proceedings in NIM

Understanding the Dynamics of Fluorescence Emission During Zeolite Detemplation Using Time Resolved Photoluminescence Spectroscopy

Time-resolved photoluminescence spectroscopy (TRPS) shows potential as a sensitive, non-destructive, high throughput, label-free laser-based spectroscopy technique capable of analysing low concentrations of organic species adsorbed on and within zeolite pores. Here we report the results from a study that uses TRPS to characterise photoluminescence (PL) arising from synthesised chabazite framework zeolites at three different stages of the detemplation process (from an uncalcined, partially calcined, and calcined zeolite). Temporal resolution was used to demonstrate the steric confinement effects of OSDA within a zeolite framework and therefore to establish a signature region for determining the presence of the template. Gated spectra comparisons between an uncalcined and a partially calcined zeolite demonstrated the presence of template alongside the proliferation of template-derived combustion products. An analysis of lifetime values demonstrated the ability for TRPS to track depletion of OSDA and establish a characteristic PL spectrum for a clean zeolite

Networks of Recurrent Events, a Theory of Records, and an Application to Finding Causal Signatures in Seismicity

We propose a method to search for signs of causal structure in spatiotemporal data making minimal a priori assumptions about the underlying dynamics. To this end, we generalize the elementary concept of recurrence for a point process in time to recurrent events in space and time. An event is defined to be a recurrence of any previous event if it is closer to it in space than all the intervening events. As such, each sequence of recurrences for a given event is a record breaking process. This definition provides a strictly data driven technique to search for structure. Defining events to be nodes, and linking each event to its recurrences, generates a network of recurrent events. Significant deviations in properties of that network compared to networks arising from random processes allows one to infer attributes of the causal dynamics that generate observable correlations in the patterns. We derive analytically a number of properties for the network of recurrent events composed by a random process. We extend the theory of records to treat not only the variable where records happen, but also time as continuous. In this way, we construct a fully symmetric theory of records leading to a number of new results. Those analytic results are compared to the properties of a network synthesized from earthquakes in Southern California. Significant disparities from the ensemble of acausal networks that can be plausibly attributed to the causal structure of seismicity are: (1) Invariance of network statistics with the time span of the events considered, (2) Appearance of a fundamental length scale for recurrences, independent of the time span of the catalog, which is consistent with observations of the ``rupture length'', (3) Hierarchy in the distances and times of subsequent recurrences.Comment: 19 pages, 13 figure