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Various Shapes (various + shape)
Selected AbstractsMeasuring Similarity Among Various Shapes Based on Geometric MatchingGEOGRAPHICAL ANALYSIS, Issue 4 2005Zuoquan Zhao The purpose of this article is to examine how to measure the degree of similarity among various shapes, including for the first time those that are fragmented and perforated, by the overlap-based elongation index. It is argued that complete removal of the effects of position, size, and orientation on shape, which is essential for the calibration of shape similarity, can be achieved by a shape similarity index that varies continuously with changes in shape. After examining the characteristics of shape change, it is demonstrated that the elongation index is sensitive to changes in the shape of two spatial objects only when the centroids of the two objects are coincident. Two related rules of shape similarity are then presented. The applicability of the elongation index is evaluated by comparing several simple and complex shapes. The principal contribution of this article is that for the first time similarity among various shapes, fragmented or perforated, can be identified using the elongation index. [source] Hierarchical Structure Recovery of Point-Sampled SurfacesCOMPUTER GRAPHICS FORUM, Issue 6 2010Marco Attene I.3 COMPUTER GRAPHICS; I.3.5 Computational Geometry and Object Modeling,Object hierarchies Abstract We focus on the class of ,regular' models defined by Várady et al. for reverse engineering purposes. Given a 3D surface,,represented through a dense set of points, we present a novel algorithm that converts,,to a hierarchical representation,. In,, the surface is encoded through patches of various shape and size, which form a hierarchical atlas. If,,belongs to the class of regular models, then,,captures the most significant features of,,at all the levels of detail. In this case, we show that,,can be exploited to interactively select regions of interest on,,and intuitively re-design the model. Furthermore,,,intrinsically encodes a hierarchy of useful ,segmentations' of,. We present a simple though efficient approach to extract and optimize such segmentations, and we show how they can be used to approximate the input point sets through idealized manifold meshes. [source] On singularities in the solution of three-dimensional Stokes flow and incompressible elasticity problems with cornersINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2004A. Dimitrov Abstract In this paper, a numerical procedure is presented for the computation of corner singularities in the solution of three-dimensional Stokes flow and incompressible elasticity problems near corners of various shape. For obtaining the order and mode of singularity, a neighbourhood of the singular point is considered with only local boundary conditions. The weak formulation of this problem is approximated using a mixed u, p Galerkin,Petrov finite element method. Additionally, a separation of variables is used to reduce the dimension of the original problem. As a result, the quadratic eigenvalue problem (P+,Q+,2R)d=0 is obtained, where the saddle-point-type matrices P, Q, R are defined explicitly. For a numerical solution of the algebraic eigenvalue problem an iterative technique based on the Arnoldi method in combination with an Uzawa-like scheme is used. This technique needs only one direct matrix factorization as well as few matrix,vector products for finding all eigenvalues in the interval ,,(,) , (,0.5, 1.0), as well as the corresponding eigenvectors. Some benchmark tests show that this technique is robust and very accurate. Problems from practical importance are also analysed, for instance the surface-breaking crack in an incompressible elastic material and the three-dimensional viscous flow of a Newtonian fluid past a trihedral corner. Copyright © 2004 John Wiley & Sons, Ltd. [source] Structural properties of (Ga,Mn)Sb thin films on GaAs(111)A substratePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2009J. Bak-Misiuk Abstract GaSb/GaAs(111)A layers with embedded Mn(Ga)Sb clusters have been grown by molecular beam epitaxy method at the substrate temperature of 450 °C. The results of structural characterization of (Ga,Mn)Sb with Mn concentration up to 8% are presented. Almost all Mn atoms introduced into the GaSb layers form hexagonal Mn(Ga)Sb clusters. Large hexagonal clusters with various shape and dimensions were detected by scanning electron microscopy. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Measuring Similarity Among Various Shapes Based on Geometric MatchingGEOGRAPHICAL ANALYSIS, Issue 4 2005Zuoquan Zhao The purpose of this article is to examine how to measure the degree of similarity among various shapes, including for the first time those that are fragmented and perforated, by the overlap-based elongation index. It is argued that complete removal of the effects of position, size, and orientation on shape, which is essential for the calibration of shape similarity, can be achieved by a shape similarity index that varies continuously with changes in shape. After examining the characteristics of shape change, it is demonstrated that the elongation index is sensitive to changes in the shape of two spatial objects only when the centroids of the two objects are coincident. Two related rules of shape similarity are then presented. The applicability of the elongation index is evaluated by comparing several simple and complex shapes. The principal contribution of this article is that for the first time similarity among various shapes, fragmented or perforated, can be identified using the elongation index. [source] Shape of "True" transition boiling curve and two-mode boilingHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2003Duu-Jong Lee Abstract Two-mode boiling could occur on the same heating element, which provided information on the criterion separating the stable and metastable boiling regimes. The "equal-area" criterion based on the complete boiling curve interpreted the criterion of coexistence of the two boiling modes. However, the transition boiling curve could not be constructed by the pool boiling tests. Literature works adopted various correlations of transition boiling curves for analysis, but failed to recognize the possible errors incorporated in such an approximation. This paper demonstrated the relative errors embedded in calculating the equal-area criterion by assuming various shapes of the transition boiling curve. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 593,601, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10113 [source] Sloshing analysis of a liquid storage container using level set X-FEMINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 4 2009Toshio Nagashima Abstract The extended finite element method (X-FEM), in conjunction with the level set method, is applied to sloshing analysis of a rigid container filled with liquid. The governing equations for liquid with a free surface based on the potential flow theory are discretized using the framework of level set X-FEM. Once the space domain of a container is modeled by tetrahedral elements, sloshing analysis for arbitrary liquid levels and configurations can be performed without remeshing. Natural frequencies of free surface sloshing motion in rigid containers of various shapes were computed by the proposed method and the results were compared with those obtained by theoretical solutions and experiments. The proposed method was demonstrated to perform sloshing analysis efficiently for rigid containers with various liquid levels and configurations. Copyright © 2008 John Wiley & Sons, Ltd. [source] On the discretization of problems involving periodic planar tilingsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 8 2001André Bénard Abstract Features related to the discretization of problems characterized by simple periodic tilings using cells of various shapes are discussed. Various cell geometries that tile the plane periodically are considered. Equivalent problems are identified, where the discretization can take place on a parallelogram, regardless of the shape of the original cell. These equivalent problems also suggest a numbering of the equations that results in matrices with interesting and useful properties. Copyright © 2001 John Wiley & Sons, Ltd. [source] Vibrations of skewed cantilevered triangular, trapezoidal and parallelogram Mindlin plates with considering corner stress singularitiesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 13 2005C. S. Huang Abstract Based on the Mindlin shear deformation plate theory, a method is presented for determining natural frequencies of skewed cantilevered triangular, trapezoidal and parallelogram plates using the Ritz method, considering the effects of stress singularities at the clamped re-entrant corner. The admissible displacement functions include polynomials and corner functions. The admissible polynomials form a mathematically complete set and guarantee the solution convergent to the exact frequencies when sufficient terms are used. The corner functions properly account for the singularities of moments and shear forces at the re-entrant corner and accelerate the convergence of the solution. Detailed convergence studies are carried out for plates of various shapes to elucidate the positive effects of corner functions on the accuracy of the solution. The results obtained herein are compared with those obtained by other investigators to demonstrate the validity and accuracy of the solution. Copyright © 2005 John Wiley & Sons, Ltd. [source] Growth Direction and Cross-Sectional Study of Silicon Nanowires,ADVANCED MATERIALS, Issue 7-8 2003C.-P. Li Cross-sectional samples of silicon nanowires (SiNWs) are examined using transmission electron microscopy. The cross-sections are bounded by well-defined low-index crystallographic facets of various shapes (e.g., the square section in the Figure, 50 nm edge) and characterized by shape-dependent growth directions, with ,112, and ,110, predominating. Both shape and growth direction are consistent with surface energy considerations and growth mechanisms. [source] Modeling UHMWPE wear debris generationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007H. Baudriller Abstract It is widely recognized that polyethylene wear debris is one of the main causes of long-term prosthesis loosening. The noxious bioreactivity associated with this debris is determined by its size, shape, and quantity. The aim of this study was to develop a numerical tool that can be used to investigate the primary polyethylene wear mechanisms involved. This model illustrates the formation of varying flow of polyethylene debris with various shapes and sizes caused by elementary mechanical processes. Instead of using the classical continuum mechanics formulation for this purpose, we used a divided materials approach to simulate debris production and release. This approach involves complex nonlinear bulk behaviors, frictional adhesive contact, and characterizes material damage as a loss of adhesion. All the associated models were validated with various benchmark tests. The examples given show the ability of the numerical model to generate debris of various shapes and sizes such as those observed in implant retrieval studies. Most of wear mechanisms such as abrasion, adhesion, and the shearing off of micro-asperities can be described using this approach. Furthermore, it could be applied to study the effects of friction couples, macroscopic geometries, and material processing (e.g. irradiation) on wear. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Micropattern formation of apatite by combination of a biomimetic process and transcription of resist patternJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 4 2002Naoshi Ozawa Abstract Two kinds of methods combining a biomimetic process and transcription of resist pattern were conducted to form an apatite micropattern. For method 1, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO-SiO2 -based glass in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. Next, apatite was grown from the nuclei by soaking the substrate in an aqueous solution with ion concentrations 1.5 times those of SBF (1.5 SBF). Then, the resist material was dissolved off by organic solvent with the apatite just formed on it. Apatite micropattern transcribing the resist pattern was obtained. For method 2, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO-SiO2 -based glass in SBF. Next, the resist material was dissolved off with the apatite nuclei just formed on it. Then, the substrate was soaked in 1.5 SBF to grow the remaining nuclei and an apatite micropattern transcribing the resist pattern was obtained. For both methods, minute apatite patterns with various shapes as straight lines, bending lines, and blocks were clearly formed. The minimum line width of the obtained pattern was 2 ,m. These methods are promising for producing multifunctional materials with bioaffinity. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 579,586, 2002 [source] Form and environment of Gryphaea arcuataLETHAIA, Issue 2 2003LAETITIA NORI Gryphaea arcuata is one of the most studied fossils, but its detailed palaeoecology has been largely neglected. Specimens were collected within a short stratigraphic range (three ammonite zones) in the ,Calcaire à gryphées' of Xeuilley (Lorraine, France) dated Hettangian to Lower Sinemurian. As far as possible, they were sampled from each marly bed of the section. A biometric study and an isotopic analysis are compared in regard to organic matter measurements and palynological data, the results demonstrating a clear relationship between the shape of G. arcuata and environmental parameters. Factors responsible for the various shapes are temperature, oxygen levels on the sea floor and nutrient levels. Two main morphotypes can be related to two kinds of environment. In the first, controlled by a relatively hot and humid climate and tending towards eutrophication, the growth rate of Gryphaea was low, and the shells small, wide and thin. In the second environment, cooler than the first one and closer to the optimal living conditions of G. arcuata, the shell was large, thick and narrow, and exhibited a high growth rate. [source] A differential medium for lactic acid-producing bacteria in a mixed cultureLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008H.M. Lee Abstract Aims:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue (mMRS-BPB) was tested as a medium for counting and differentiation of each lactic acid-producing bacterium (LAB), especially in a mixed culture. Methods and Results:, Type strains of 10 LAB species (Lactobacillus acidophilus, L. brevis, L. bulgaricus, L. gasseri, L. paracasei, L. plantarum, L. reuteri, Weissella confusa, Bifidobacterium bifidum and B. infantis) and five commercial yogurts were inoculated on plate count agar with bromocresol purple, mMRS, and mMRS-BPB. Each type strain showed more clearly formed colonies on the three media under anaerobic conditions than under aerobic conditions. Especially each type strain produced colonies with specific characteristics of each species on mMRS-BPB. Commercial yogurts produced the largest number of colonies with various shapes and colours on mMRS-BPB. Conclusions:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue under anaerobic conditions is appropriate for counting and differentiating each LAB in a mixed culture. Significance and Impact of the Study:, Modified deMan-Rogosa Sharpe agar containing bromophenol blue will be useful in isolation and enumeration of each LAB from fermented foods as well as intestinal microflora. [source] The power of national symbols: the credibility of a dragon's efficacyNATIONS AND NATIONALISM, Issue 3 2002Margaret Sleeboom It is only when symbols gain meaning as effective triggers of associated sentiments in many linked contexts, including that of daily life, that they become powerful. It is what is perceived as the proved ability of the state to correct disobedience to its rule and violation to its sovereignty that commands commitment and loyalty, necessary for state symbols to become effective. As long as the link between symbol and effect can be made credible as a natural connection of cause and effect, by rational or irrational means, by folk narrative or academic theory, triggering the national symbol works in the mind of its believers. In this article I discuss the role of academics in the creation of national symbolism. Using some examples of historical and anthropological interpretations of the notion of the dragon, I argue that the cognitive aspect of nationalism is of crucial importance to the efficacy of national symbols. Thus arguments on the dragon' various shapes, origins and merits as totem, embryo and sea snake attach and support different symbolic and political meanings of the Chinese nation. [source] Selective area heteroepitaxy of low dimensional a -plane and c -plane InGaN nanostructures using pulsed MOCVDPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008V. Jindal Abstract High density a -plane and c -plane InGaN nanostructures have been developed by nanoscale selective area epitaxial growth using pulsed MOCVD. SiO2 was used as a mask with nanopatterning through an anodic aluminum oxide template. The lateral dimensions of the pattern were controlled and varied from 30 nm to 180 nm by changing the anodization voltage and the electrolyte. Different substrates such as a -plane GaN on r -plane sapphire, r -plane sapphire and c -plane sapphire were used to develop InGaN nanostructures in a - and c - crystallographic directions respectively. Under identical growth conditions, InGaN nanostructures of various shapes were obtained on different substrates with differences in emission wavelength. The shape of the nanostructures on different substrates is discussed with respect to the stability and growth rates of various planes. However, the difference in emission wavelength is attributed to the In incorporation in the nanostructures. The optical properties of the nanostructures were studied by photoluminescence (PL) spectroscopy. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Control Charts for Monitoring Field Failure DataQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 7 2006Robert G. Batson Abstract One responsibility of the reliability engineer is to monitor failure trends for fielded units to confirm that pre-production life testing results remain valid. This research suggests an approach that is computationally simple and can be used with a small number of failures per observation period. The approach is based on converting failure time data from fielded units to normal distribution data, using simple logarithmic or power transformations. Appropriate normalizing transformations for the classic life distributions (exponential, lognormal, and Weibull) are identified from the literature. Samples of size 500 field failure times are generated for seven different lifetime distributions (normal, lognormal, exponential, and four Weibulls of various shapes). Various control charts are then tested under three sampling schemes (individual, fixed, and random) and three system reliability degradations (large step, small step, and linear decrease in mean time between failures (MTBF)). The results of these tests are converted to performance measures of time to first out-of-control signal and persistence of signal after out-of-control status begins. Three of the well-known Western Electric sensitizing rules are used to recognize the assignable cause signals. Based on this testing, the ,X -chart with fixed sample size is the best overall for field failure monitoring, although the individual chart was better for the transformed exponential and another highly-skewed Weibull. As expected, the linear decrease in MTBF is the most difficult change for any of the charts to detect. Copyright © 2005 John Wiley & Sons, Ltd. [source] Positron Emission Tomography Applied to Fluidization EngineeringTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2005Chutima Dechsiri Abstract The movement of particles in a laboratory fluidized bed has been studied using Positron Emission Tomography (PET). With this non-invasive technique both pulses of various shapes and single tracer particles were followed in 3-D. The equipment and materials used made it possible to label actual bed particles as tracer. This paper briefly describes the data analysis, some of the results and compares them with a stochastic model. The results confirm the basic assumptions of the model qualitatively but not quantitatively. Further analysis of the results indicates that the system exhibits gulf-streaming, a feature which is not yet accounted for in the model, but is common in fluidized beds in practice. On a étudié le mouvement des particules dans un lit fluidisé de laboratoire par la tomographie à émission de positrons (PET). Cette technique non intrusive a permis de suivre en 3-D des impulsions de formes diverses aussi bien que des particules traçantes uniques en 3-D. L'équipement et les matériaux utilisés ont permis d'employer des particules de lit réelles comme traceurs. On décrit brièvement dans cet article l'analyse des données et certains des résultats, puis une comparaison est effectuée avec un modèle stochastique. Les résultats confirment les hypothèses de base du modèle de façon qualitative mais non quantitative. Une analyse plus approfondie des résultats indique que le système montre un phénomène de « gulf-streaming », une caractéristique pas encore prise en compte dans le modèle mais qui est courante dans les lits fluidisés réels. [source] Complete mapping of glomeruli based on sensory nerve branching pattern in the primary olfactory center of the cockroach Periplaneta americanaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 19 2010Hidehiro Watanabe Abstract Glomeruli are structural and functional units in the primary olfactory center in vertebrates and insects. In the cockroach Periplaneta americana, axons of different types of sensory neurons housed in sensilla on antennae form dorsal and ventral antennal nerves and then project to a number of glomeruli. In this study, we identified all antennal lobe (AL) glomeruli based on detailed innervation patterns of sensory tracts in addition to the shape, size, and locations in the cockroach. The number of glomeruli is ,205, and no sex-specific difference is observed. Anterograde dye injections into the antennal nerves revealed that axons supplying the AL are divided into 10 sensory tracts (T1,T10). Each of T1,T3 innervates small, oval glomeruli in the anteroventral region of the AL, with sensory afferents invading each glomerulus from multiple directions, whereas each of T4,T10 innervates large glomeruli with various shapes in the posterodorsal region, with a bundle of sensory afferents invading each glomerulus from one direction. The topographic branching patterns of all these tracts are conserved among individuals. Sensory afferents in a sub-tract of T10 had axon terminals in the dorsal margin of the AL and the protocerebrum, where they form numerous small glomerular structures. Sensory nerve branching pattern should reflect developmental processes to determine spatial arrangement of glomeruli, and thus the complete map of glomeruli based on sensory nerve branching pattern should provide a basis for studying the functional significance of spatial arrangement of glomeruli and its developmental basis. J. Comp. Neurol. 518:3907,3930, 2010. © 2010 Wiley-Liss, Inc. [source] Basic Types and Structural Characteristics of Uplifts: An Overview of Sedimentary Basins in ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Dengfa HE Abstract: The uplift is a positive structural unit of the crust It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19,3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types , the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can be subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones (belts) with multiple productive formations and various types of oil and gas reservoirs. [source] | ||||||||||||||||||||||