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Oblique Angles (oblique + angle)
Selected AbstractsCompton scattering of Fe K, lines in magnetic cataclysmic variablesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2008A. L. McNamara ABSTRACT Compton scattering of X-rays in the bulk flow of the accretion column in magnetic cataclysmic variables (mCVs) can significantly shift photon energies. We present Monte Carlo simulations based on a non-linear algorithm demonstrating the effects of Compton scattering on the H-, He-like and neutral Fe K, lines produced in the post-shock region of the accretion column. The peak line emissivities of the photons in the post-shock flow are taken into consideration and frequency shifts due to Doppler effects are also included. We find that line profiles are most distorted by Compton scattering effects in strongly magnetized mCVs with a low white dwarf mass and high mass accretion rate and which are viewed at an oblique angle with respect to the accretion column. The resulting line profiles are most sensitive to the inclination angle. We have also explored the effects of modifying the accretion column width and using a realistic emissivity profile. We find that these do not have a significant overall effect on the resulting line profiles. A comparison of our simulated line spectra with high-resolution Chandra/HETGS observations of the mCV GK Per indicates that a wing feature redward of the 6.4-keV line may result from Compton recoil near the base of the accretion column. [source] An astronomical pattern-matching algorithm for computer-aided identification of whale sharks Rhincodon typusJOURNAL OF APPLIED ECOLOGY, Issue 6 2005Z. ARZOUMANIAN Summary 1The formulation of conservation policy relies heavily on demographic, biological and ecological knowledge that is often elusive for threatened species. Essential estimates of abundance, survival and life-history parameters are accessible through mark and recapture studies given a sufficiently large sample. Photographic identification of individuals is an established mark and recapture technique, but its full potential has rarely been exploited because of the unmanageable task of making visual identifications in large data sets. 2We describe a novel technique for identifying individual whale sharks Rhincodon typus through numerical pattern matching of their natural surface ,spot' colourations. Together with scarring and other markers, spot patterns captured in photographs of whale shark flanks have been used, in the past, to make identifications by eye. We have automated this process by adapting a computer algorithm originally developed in astronomy for the comparison of star patterns in images of the night sky. 3In tests using a set of previously identified shark images, our method correctly matched pairs exhibiting the same pattern in more than 90% of cases. From a larger library of previously unidentified images, it has to date produced more than 100 new matches. Our technique is robust in that the incidence of false positives is low, while failure to match images of the same shark is predominantly attributable to foreshortening in photographs obtained at oblique angles of more than 30°. 4We describe our implementation of the pattern-matching algorithm, estimates of its efficacy, its incorporation into the new ECOCEAN Whale Shark Photo-identification Library, and prospects for its further refinement. We also comment on the biological and conservation implications of the capability of identifying individual sharks across wide geographical and temporal spans. 5Synthesis and applications. An automated photo-identification technique has been developed that allows for efficient ,virtual tagging' of spotted animals. The pattern-matching software has been implemented within a Web-based library created for the management of generic encounter photographs and derived data. The combined capabilities have demonstrated the reliability of whale shark spot patterns for long-term identifications, and promise new ecological insights. Extension of the technique to other species is anticipated, with attendant benefits to management and conservation through improved understanding of life histories, population trends and migration routes, as well as ecological factors such as exploitation impact and the effectiveness of wildlife reserves. [source] Macroscopic Characteristics of Screwdriver TraumaJOURNAL OF FORENSIC SCIENCES, Issue 6 2007Alexandra M. Croft M.Sc. Abstract:, The main objective of the study was to determine the type of macroscopic trauma created by a flat-tipped and a cross-tipped screwdriver. The second objective was to determine if the trauma inflicted by the two screwdrivers could be macroscopically differentiated. Three tests were conducted, each by a male volunteer. Each test consisted of 12 samples of fleshed pig ribs; six were stabbed with a flat-tipped screwdriver and the remaining six with a cross-tipped screwdriver (Phillips®). Each sample received 15 stab wounds during the process. The stabbings were conducted at perpendicular and oblique angles, with fabric variables being utilized. Results illustrate two main categories of macroscopic skeletal trauma, fractures, and puncture wounds. By studying the macroscopic appearance in tandem with differing trauma frequencies, these two screwdriver types can be differentiated. [source] Compact angularly stable frequency selective surface using hexagonal fractal configurationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009Wentao T. Wang Abstract A compact bandstop frequency selective surface (FSS) using fractal structure is proposed. This flexuous design elongates the cell perimeter of the ring-shaped FSS, which means the cell size gets smaller at the same resonance frequency. Furthermore, the unit cells adopt regular hexagon and the array employs equilateral triangle form. Because of its symmetric configuration, good frequency stability has been achieved for both horizontal and vertical polarizations at different oblique angles. For the stable bandstop character, this FSS can be used for protecting the staff of S-band radars against electromagnetic radiation, while the 900/1800/1900 MHz mobile bands and the 5.2/5.8 GHz wireless local area network signals are not affected. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2541,2544, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24676 [source] Conductive nanodots on the surface of irradiated CaF2PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 5 2008Tino Roll Abstract CaF2(111) single crystal surfaces have been irradiated with fast heavy ions under oblique angles resulting in chains of nanosized hillocks. In order to characterize these nanodots with respect to their conductivity we have applied non-contact atomic force microscopy using a magnetic tip. Measurements in ultra high vacuum as well as under ambient conditions reveal a clearly enhanced electromagnetic interaction between the magnetic tip and the nanodots. The dissipated energy per cycle is comparable to the value found for metals, indicating that the interaction of the ion with the target material leads to the creation of metallic Ca nanodots on the surface. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||