Swift Observations of X-ray supernovae

We present a result of X-ray supernovae (SNe) survey using the Swift satellite public archive. An automatic searching program was designed to search X-ray SNe among all of the Swift archival observations between November 2004 and February 2011. Using the C++ program, 24 X-ray detectable supernovae have been found in the archive and 3 of them were newly-discovered in X-rays which are SN 1986L, SN 2003lx, and SN 2007od. In addition, SN 2003lx is a Type Ia supernova which may be the second X-ray detectable Type Ia after SN 2005ke (Immler et al. 2006). Calibrated data of luminous type Ib/c supernovae was consistent to the X-ray emission model done by Chevalier & Fransson (1994). Statistics about the luminosities and hardness ratio have been done to purpose of getting the X-ray emission features of the X-ray supernovae. The results from this work help investigating the X-ray evolution of SNe and developing similar X-ray SNe surveys in various X-rays missions

Solo and solid geometry : interpreting upper primary students' representations of the three-dimensional geometrical shapes and their development of three-dimensional visualization

University of Technology, Sydney. Faculty of Arts and Social Sciences.Within the study of the three-dimensional (3D) geometry in the primary school curriculum is the development of students’ spatial visualization, the ability to visualize the 3D geometrical shapes. Both the National Council of Teachers of Mathematics in the States and the Curriculum Development Council in Hong Kong emphasis that all students should have opportunities to visualize and work with 3D shapes in order to develop spatial skills fundamental to everyday life and to many careers. This research is a study about how a sample of 297 upper primary students in Hong Kong describe in (Chinese) words about, and draw on papers, the 3D geometrical shapes. Theses shapes include cube, triangular prism, pyramid and cylinder. The focus is on the interpretation of the diversity of the responses used in students’ descriptions and on the exploration of students’ development of visualization by their drawings of the four 3D shapes. It raises issues about upper primary students’ spatial ability and the need to conceptualize 3D spatial ability within board theoretical frameworks in the literature. The theoretical models of different aspects are explored: Bishop’s IFI and VP spatial abilities be adopted to define the scopes of spatial abilities; Van Hiele’s levels of geometry learning be the basis of the macro stages of cognitive development; and the Prestructural-Unistructural-Multistructural-Relational (P-U-M-R) sequence in the SOLO model be the micro levels of cognitive development growth. Epistemologically, the view of knowledge in this study is based on Vygotsky’s socialcultural perspective. The grounded theory approach and the interpretive approach are adopted for the research methodology. A fundamental finding is that the response patterns about the descriptions and the drawings of the 3D geometrical shapes are rich and diverse. Also, the findings support the P-U-M-R levels of the SOLO model and provide a set of descriptors of students’ developmental representation patterns for the four levels both in descriptions and drawings underpinned by the theoretical framework achieved in this study. This study concludes with recommendations for explicit instructions on the 3D geometrical shapes such as the 3D geometrical vocabulary, 3D drawing conventions, the static nature of representational drawings on papers, building up the coordination views, the partial occlusion technique, hands-on activities with real objects and relating 3D objects in the real world

Possible TeV Source Candidates In The Unidentified EGRET Sources

We study the $\gamma$-ray emission from the pulsar magnetosphere based on outer gap models, and the TeV radiation from pulsar wind nebulae (PWNe) through inverse Compton scattering using a one-zone model. We showed previously that GeV radiation from the magnetosphere of mature pulsars with ages of $\sim 10^5-10^6$ years old can contribute to the high latitude unidentified EGRET sources. We carry out Monte Carlo simulations of $\gamma$-ray pulsars in the Galaxy and the Gould Belt, assuming the pulsar birth rate, initial position, proper motion velocity, period, and magnetic field distribution and evolution based on observational statistics. We select from the simulation a sample of mature pulsars in the Galactic plane ($|b|\leq 5^\circ$) and in the high latitude ($|b|> 5^\circ$) which could be detected by EGRET. The TeV flux from the pulsar wind nebulae of our simulated sample through the inverse Compton scattering by relativistic electrons on the microwave cosmic background and synchrotron seed photons are calculated. The predicted fluxes are consistent with the present observational constraints. We suggest that strong EGRET sources can be potential TeV source candidates for present and future ground-based TeV telescopes.Comment: Minor changes, MNRAS in pres

Do equal land and water rights benefit the poor?: Targeted irrigation development: The case of the Andhi Khola Irrigation Scheme in Nepal

Irrigation programs / Water rights / Poverty / Households / Surveys / Water allocation / Water distribution / Water users’ associations / Farmers / Landlessness / Land ownership

Phase resolved PLIF and chemiluminescence for measuring combustion dynamics

Transient behavior of combustion systems has long been a subject of both fundamental and practical concerns. Extreme cases of very rapid changes include the ignition of reacting mixtures and detonation. At the other extreme is a wide range of quasi-steady changes of behavior, for example adjustments of the operating point of a combustion chamber. Between the limiting cases of 'infinitely fast' and 'infinitesimally slow' lie important fundamental problems of time-dependent behavior and a wide array of practical applications. Among the latter are combustion instabilities and their active control, a primary motivation for the work reported in this paper. Owing to the complicated chemistry, chemical kinetics and flow dynamics of actual combustion systems, numerical simulations of their behavior remains in a relatively primitive state. Even as that situation continually improves, it is an essential part of the field that methods of measuring true dynamical behavior be developed to provide results having both fine spatial resolution and accuracy in time. This paper is a progress report of recent research carried out in the Jet Propulsion Center of the California Institute of Technology

Web enabled just-in-time salvaged material management for demolition projects

The demolition activities of buildings produce numerous environmental pressures as a large proportion of demolition waste materials are sent to landfill directly in many projects. Web-based waste exchange systems could provide right solutions for releasing these pressures. Because the approaches adopted in current waste exchange systems are inefficient, these systems cannot generate waste exchange, not achieving their final goal, environmental protection. The Just-in-time (JIT) philosophy has been applied in the manufacture industry for decades and it is proven to be effective to eliminate or minimise inventory during production. This research aims to adopt the JIT philosophy into a demolition project management informapon system so that the system is more efficient in handling waste exchange. The system structure, key components and Just-in-time adoption are proposed and identified. Finally, a proto typed system is demonstrated.<br /

Information technology applications for planning in deconstruction

In recent years, there has been obvious emphasis on the shift from design and construction of new facilities to maintenance, refurbishment, and demolition management of existing facilities. Demolition technology has gradually changed from conventional destruction to the recently developed deconstruction. Demolition management, particularly deconstruction management, is becoming a novel, but a fertile teaching and research discipline. This paper focuses on an important issue of deconstruction management, how to work out a deconstruction plan using information technologies.<br /

The Discovery of an X-ray/UV Stellar Flare from the Late-K/Early-M Dwarf LMC 335

We report the discovery of an X-ray/UV stellar flare from the source LMC 335, captured by XMM-Newton in the field of the Large Magellanic Cloud. The flare event was recorded continuously in X-ray for its first 10 hours from the precursor to the late decay phases. The observed fluxes increased by more than two orders of magnitude at its peak in X-ray and at least one in the UV as compared to quiescence. The peak 0.1-7.0 keV X-ray flux is derived from the two-temperature APEC model to be ~(8.4 +/- 0.6) x 10^-12 erg cm-2 s-1. Combining astrometric information from multiple X-ray observations in the quiescent and flare states, we identify the NIR counterpart of LMC 335 as the 2MASS source J05414534-6921512. The NIR color relations and spectroscopic parallax characterize the source as a Galactic K7-M4 dwarf at a foreground distance of (100 - 264) pc, implying a total energy output of the entire event of ~(0.4 - 2.9) x 10^35 erg. This report comprises detailed analyses of this late-K / early-M dwarf flare event that has the longest time coverage yet reported in the literature. The flare decay can be modeled with two exponential components with timescales of ~28 min and ~4 hours, with a single component decay firmly ruled out. The X-ray spectra during flare can be described by two components, a dominant high temperature component of ~40-60MK and a low temperature component of ~10MK, with a flare loop length of about 1.1-1.3 stellar radius.Comment: 35 pages, 6 figures, 5 tables, accepted for publication in Ap