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Geometrical Considerations (geometrical + consideration)
Selected AbstractsAnalysis of fundamental light receiving characteristics of spherical solar cellsELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 6 2008Hiroki Ishikawa Abstract Spherical solar cells are claimed to have some advantageous characteristics superior to those of ordinary planar solar cells. The most significant one is that the spherical solar cells have no directivity to light. This paper examines the characteristics based on geometrical considerations. The authors prove that a single spherical cell has no directivity as a whole. In practical use, many cells are used in an array configuration, where an individual cell receives the shadows cast by other cells around it. The adjacent shadows, so named in this paper, cause directivity. Their effects are evaluated geometrically and the theoretical considerations are verified through experiments. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(6): 34,46, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10119 [source] Flow Kinetics in Porous Ceramics: Understanding with Non-Uniform Capillary ModelsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2007Debdutt Patro The present work describes the development of a two-parameter non-uniform capillary model to describe kinetics of flow in porous solids with complex tortuous varying paths. Experimentally, the rate of fluid flow in such a non-uniform capillary is found to be orders of magnitude slower compared with a corresponding average uniform capillary. This slow rate is explained in terms of an extremely small ,effective' hydrodynamic radius. The origin of such an ,unphysical' radius is rationalized based on geometrical considerations and effective driving forces for flow through a stepped capillary. Infiltration rate parameters are derived from the geometry of the porous medium for both wetting and non-wetting conditions. [source] On symmetry classes of crystal structuresACTA CRYSTALLOGRAPHICA SECTION A, Issue 6 2009Hans Burzlaff An open-ended classification scheme for crystal structures based on Wyckoff sets and affine normalizer groups is proposed. It is free of metrical and geometrical considerations. All structures of one structure type belong to the same symmetry class. An application is given for the Inorganic Crystal Structure Database (version 2, 2007). [source] Double resonance ejection in a micro ion trap mass spectrometerRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2002Jeremy Moxom Ion ejection from a cylindrical micro ion trap by resonance excitation of the secular motion is observed to be strongly dependent on the frequency of the secular motion at resonance. Both the intensity of the ion signal and the mass resolution of the resulting mass spectrum are increased when the ion secular frequency is approximately that of a nonlinear resonance of the trap. The resonances are attributed to electrical as well as geometrical considerations. Copyright © 2002 John Wiley & Sons, Ltd. [source] Identification and removal of above-ground spurious signals in GPR archaeological prospecting,ARCHAEOLOGICAL PROSPECTION, Issue 2 2005Luigia Nuzzo Abstract Ground-penetrating radar (GPR) is a shallow geophysical method increasingly used in archaeological prospecting to detect buried remains and to map the stratigraphy of the uppermost earth layers embodying the archaeological features. The GPR sections, however, can be contaminated by spurious correlated signals caused by above-ground obstacles (buildings, trees, fences, power lines) placed either in-line or off-line with respect to the profile (surface scattering). In the case study presented this problem is analysed for a 35,MHz GPR survey carried out for stratigraphical purposes in the archaeological site of the Roman Ships near Pisa (Italy). The investigation inside the archaeological excavation, when the level was about 5,m below the ground surface, produced a severe surface scattering problem caused by the iron sheet-piling protecting the excavation walls and bordering some of the partly excavated boats. An attempt to interpret the profiles was carried out in a zone where the relatively simple geometry of the metallic enclosure allowed understanding of the possible origin of spurious events, also thanks to the high density of profiles acquired along two orthogonal directions. Migration at the air velocity and geometrical considerations helped the identification of hyperbolic and slightly slanted features as surface scattering phenomena from different sides of the iron sheet-piling. A simple but original subtraction procedure was successful for the attenuation of some of the spurious reflections. After this partial removal, other spurious signals could be recognized more easily as well as two weak subhorizontal reflections of probable stratigraphical meaning. Subsequently, filtering procedures based on f-k and Radon transform methods were tried to further reduce the spurious signals, thus enhancing the visibility of the interesting reflections. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||