Survey, analysis and evaluation test on high voltage/current pulse transmission cables

A survey, analysis, and testing of available cable connector configurations were carried out in connection with transmission of high voltage/current to an exploding wire bridge. Transmission was desired at high efficiency with maximum cable flexibility, at minimum weight and size of the cable connector, with maximum cable length while maintaining applicable voltage/current pulse characteristics, and with due consideration to environmental parameters

Policy evaluation with temporal differences: a survey and comparison

Policy evaluation is an essential step in most reinforcement learning approaches. It yields a value function, the quality assessment of states for a given policy, which can be used in a policy improvement step. Since the late 1980s, this research area has been dominated by temporal-difference (TD) methods due to their data-efficiency. However, core issues such as stability guarantees in the off-policy scenario, improved sample efficiency and probabilistic treatment of the uncertainty in the estimates have only been tackled recently, which has led to a large number of new approaches. This paper aims at making these new developments accessible in a concise overview, with foci on underlying cost functions, the off-policy scenario as well as on regularization in high dimensional feature spaces. By presenting the first extensive, systematic comparative evaluations comparing TD, LSTD, LSPE, FPKF, the residual- gradient algorithm, Bellman residual minimization, GTD, GTD2 and TDC, we shed light on the strengths and weaknesses of the methods. Moreover, we present alternative versions of LSTD and LSPE with drastically improved off-policy performance

Crossing the date-line: Perspectives of Canadian students studying education in an Australian university

The research reported here aims to develop understandings around the expectations and perceptions of Canadian students entering a Graduate Diploma of Education program in an Australian university. The study align well with the theme of "crossing borders", as the study focuses on international students "crossing borders" to achieve their accreditation goals in another country. The particular context of this research is a sizeable cohort (90-100 annually) of Canadian students who attend an Australian regional university to gain a teaching qualification. Based on the theoretical perspective of interpretivism, the study employed qualitative methods to understand the expectations and perspectives of the students early in, and during their progress through the program. Data were collected using semi-structured interviews: researchers conducted three interviews with each participant across the first six months of the students" year long stay. The "moments" of each interview were: (i) prior to attending their first week of lectures; (ii) after they had completed the first lecture series of four courses; and (iii) after participants completed their first block of practical experience in an Australian school. The data was then analysed using constant interrogation and context theory. This report is based on the initial findings of these interviews and identifies the themes and understandings expressed by the Canadian students who have "crossed the date line". The findings will be presented in four main themes that have emerged from the data: personal growth; cultural experiences; development of teacher identity; and the implications for university programs. Collectively the data highlight the concepts of global perspectives, the internationalization of university programs, and the issues of teacher identity. As the participants developed their ideas and understandings about themselves within the program, further confirmation was gained to suggest that participants entered the program with this perspective. Participants also demonstrated an intention to develop a clearly independent personal and professional identity for themselves and saw the year of study abroad as an opportunity to explore their own personal strengths and weaknesses. This corresponds with Geijsel and Meijers (2005) definition of identity and the implications of the development of identity seen through the data. Finally the initial findings indicate that universities accepting international students into their programs have a broad range of professional and ethical responsibilities in the development of global teachers with a global perspective. With regard to the case study university, the findings suggest that Australian universities which invite international students tend to rely on individual students developing a global perspective rather than adding to or enhancing this perspective

Sandia National Laboratories results for the 2010 criticality accident dosimetry exercise, at the CALIBAN reactor, CEA Valduc France.

This document describes the personal nuclear accident dosimeter (PNAD) used by Sandia National Laboratories (SNL) and presents PNAD dosimetry results obtained during the Nuclear Accident Dosimeter Intercomparison Study held 20-23 September, 2010, at CEA Valduc, France. SNL PNADs were exposed in two separate irradiations from the CALIBAN reactor. Biases for reported neutron doses ranged from -15% to +0.4% with an average bias of -7.7%. PNADs were also exposed on the back side of phantoms to assess orientation effects

Synthesis and characterization of La_0.8Sr_1.2Co_0.5M_0.5O_4-? (M=Fe, Mn)

The M4+-containing K2NiF4-type phases La0.8Sr1.2Co0.5Fe0.5O4 and La0.8Sr1.2Co0.5Mn0.5O4 have been synthesized by a sol-gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and Mössbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M4+ to M3+ and of Co3+ to Co2+. The vacancies are confined to the equatorial planes of the K2NiF4-type structure. A partial reduction of Mn3+ to Mn2+ also occurs to achieve the oxygen stoichiometry in La0.8Sr1.2Co0.5Mn0.5O3.6. La0.8Sr1.2Co0.5Fe0.5O3.65 contains Co2+ and Fe3+ ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La0.8Sr1.2Co0.5Fe0.5O4, La0.8Sr1.2Co0.5Mn0.5O4 and La0.8Sr1.2Co0.5Mn0.5O3.6 induce spin glass properties in these phases

A subduction origin for komatites and cratonic lithospheric mantle

We present a model in which the generation of komatiites in Archaean subduction zones produced depleted mantle residues that eventually formed the highly depleted portions of the Kaapvaal lithospheric mantle. The envisioned melting process is similar to that which has formed boninites in Phanerozoic subduction zones such as the Izu-Bonin-Mariana arc. The primary differences between the Archaean and Phanerozoic melting regimes are higher mean melting temperatures (1450 versus 1350 °C) and higher mean melting pressures (2.5 versus 1.5 GPa) for the komatiites. The komatiites from the Komati Formation in the Barberton greenstone belt are mafic enough to have produced the depletion seen in most Kaapvaal granular peridotite xenoliths. However, the most highly depleted Kaapvaal xenoliths require an even more Mg-rich magma than the Komati komatiites (Kk). Samples of boninite mantle residues from the fore-arc of the Marianas subduction zone are nearly as depleted as the Kaapvaal cratonic mantle, indicating that buoyant, craton-like mantle is being produced today. We speculate that production rates of cratonic mantle were greater in the Archaean due to the greater depth of melting for komatiites (relative to boninites) and greater worldwide arc length. The high production rates and high buoyancy of the komatiite mantle residues gave rise to the rapid growth and stabilization of the Kaapvaal craton in the Archaean