Using Superconducting Magnet to Reproduce Quick Variations of Gravity in Liquid Oxygen

A ground based facility (OLGA), providing magnetic compensation of gravity in oxygen, has been developed. A 2-T superconducting magnetic solenoid is used to create the required magnetic field. A novel electrical supply permits to quickly vary the magnetic field, leading to rapid variation of the acceleration forces applied to oxygen. These variations can be made from overcompensation of gravity (−0.5g) to zero gravity or from zero gravity to reduced gravity (0.4g) with a time constant of 340 ms. This time is typical of the cutoff or reignition of spacecraft engines. Preliminary results on the transient flows induced by these acceleration variations in a reservoir filled with liquid and gaseous oxygen are presented.     

An empirical investigation of individual differences in time to learn.

Studied the magnitude and stability of individual differences in the amount of time required to achieve a criterion level of performance (time-to-criterion). Time-to-criterion was defined by (a) the amount of elapsed time and (b) the amount of on-task time required to attain the criterion. 90 8th graders were randomly assigned either to a mastery learning class in which all Ss were helped to attain an 85% mastery standard or to 1 of 2 nonmastery classes. Ss learned a 3-unit sequence of programmed material in matrix arithmetic. Results from the 82 Ss who completed the study indicate that time-to-criterion (defined in both manners) was an alterable human characteristic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A numerical Maxwell-Schrödinger model for intense laser-matter interaction and propagation

We present in this paper an original ab initio Maxwell-Schrödinger model and a methodology to simulate intense ultrashort laser pulses interacting with a 3D H⁺₂-gas in the nonlinear nonperturbative regime under and beyond Born-Oppenheimer approximation. The model we present is the first one to our knowledge (excepted in [E. Lorin, S. Chelkowski, A. Bandrauk, A Maxwell-Schrödinger model for non-perturbative laser-molecule interaction and some methods of numerical computation, Proceeding CRM, vol. 41, American Mathematics Society, 2007], where a one-dimensional version is presented) to be totally nonperturbative, vectorial and multidimensional, taking into account ionization, and high order nonlinearities going far beyond classical nonlinear Maxwell or Schrödinger models. After a presentation of the model and a short mathematical study, we examine some numerical approximations for its computation. In particular, we focus on the polarization computation allowing an efficient coupling between the Maxwell and time dependent Schrödinger equations (TDSE), and on an efficient parallelization. Examples of numerical computations of high order harmonic generation and of electric field propagation are presented for one molecule and up to 512, thus highlighting cooperative effects in harmonic generation at high order.     

The ASC-Alliance Projects: A Case Study of Large-Scale Parallel Scientific Code Development

Computational scientists face many challenges when developing software that runs on large-scale parallel machines. However, software-engineering researchers haven't studied their software development processes in much detail. To better understand the nature of software development in this context, the authors examined five large-scale computational science software projects operated at the five ASC-Alliance centers.     

History of geothermal exploration in Indonesia from 1970 to 2000

Reconnaissance surveys undertaken since the 1960s show that more than 200 geothermal prospects with significant active surface manifestations occur throughout Indonesia. Some 70 of these were identified by the mid-1980s as potential high-temperature systems using geochemical criteria of discharged thermal fluids. Between 1970 and 1995, about 40 of these were explored using geological mapping, geochemical and detailed geophysical surveys. Almost half of the surveyed prospects were tested by deep (0.5–3 km) exploratory drilling, which led to the discovery of 15 productive high-temperature reservoirs. Several types of reservoirs were encountered: liquid-dominated, vapour-dominated, and a vapour layer/liquid-saturated substratum type. All three may be modified by upflows (plumes) containing magmatic fluid components (volcanic geothermal systems). Large, concealed outflows are a common feature of liquid-dominated systems in mountainous terrain. All explored prospects are hosted by Quaternary volcanic rocks, associated with arc volcanism, and half occur beneath the slopes of active or dormant stratovolcanoes. By 1995, five fields had been developed by drilling of production wells; three of them supplied steam to plants with a total installed capacity of 305 MW_e. By 2000, with input from foreign investors, the installed capacity had reached 800 MWe in six fields, but geothermal developments had stalled because of the 1997–1998 financial crisis.     

Beitrag zur Frage des Verhaltens von Turbinen- und Generatorwellen im Warmrundlaufversuch

Analyse des Eigenspannungszustandes zylindrischer Körper. Einfluß unterschiedlicher Abkühlungsbedingungen nach dem Anlassen, nach dem Spannungsarmglühen und während des Warmrundlaufversuches sowie des Verzuges während des Anlassens und einer einseitigen mechanischen Bearbeitung auf das Verhalten im Warmrundlaufversuch. Einfluß der Prüftemperatur auf die mechanischen Eigenschaften. Empfehlungen für neue Prüfrichtlinien.     

Fusion of the craniocervical transition with "CerviFix" after survived atlanto-occipital dislocation

The mechanism by which particular MHC class II alleles mediate susceptibility to a given autoimmune disease is unknown. During the past year, reports have indicated that the effects of MHC class II alleles which protect against type I diabetes in the nonobese diabetic mouse strain may, in some cases, be due to negative selection of diabetogenic T cell receptors and, in other cases, to positive selection of other T cells with a suppressive action on the diabetic process. Progress towards understanding the mechanisms of susceptibility continues to lag.     

Application of a new processing procedure for the further improvement of nuclear grade structural VCD steels

The enhancement of the quality of NiCrMoV-steels for turbine rotors and generator shafts by use of the vacuum carbon deoxidation (VCD) method is well known and established.So far the application of the VCD method has been limited to those steels which were not required to be made as fine grained steels and which consequently could be produced without the addition of aluminium.Klöckner Works have developed a method which allows the use of VCD — i.e. deoxidation of the steel by gaseous CO-reaction — with subsequent addition of Al for grain refinement. This new steel making process combines the advantages of a VCD steel with those of a fine grained steel.Seven production ingots of the steel 20 MnMoNi 5 5 have been produced by this process. The properties of the forgings made of these ingots are compared with forgings of Si/Al-deoxidized ingots. The VCD method has a beneficial influence of A-segregations. Sulphur prints show practically no segregation streaks. An improvement of impact properties and a greater isotropy of properties is gained by the VCD method.The excellent weldability of this steel could be demonstrated by weld simulation tests. There was be no susceptibility to cold cracking which was observed with SA 508 C1.3 forgings when the austenitic overlay cladding was welded on areas with A-segregations.In general the application of the VCD process to SA 508 C1.3 results in a remarkable improvement of material properties such as toughness and weldability and therefore renders components of higher reliability.     

The contribution of the solar aureole to the measurements of pyrheliometers

The fraction of the intensity measured by a currently manufactured Eppley Normal Incidence Pyrheliometer (N.I.P.), within three annular regions of the solar aureole, has been determined during 8 days. This fraction was determined by measuring the adjusted voltage difference between the N.I.P. and a modified N.I.P., divided by a corrected output voltage of the N.I.P. The fraction of intensity within the aureole was generally found to have little effect on the intensity measured by the N.I.P., even on hazy day. The data taken indicates a linear relationship between the fraction of the direct beam intensity scattered into the aureole and the total extinction coefficient of the atmosphere.     

On the nature of doping effect of methane in ZnO thin films deposited by RF-magnetron sputtering

Journal of Materials Science: Materials in Electronics - A comparative study of the effects of methane and hydrogen as reactive agents on the structural, optical, and electrical properties of ZnO...