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Three-dimensional Objects (three-dimensional + object)
Selected AbstractsTechnical note: Morphometric maps of long bone shafts and dental roots for imaging topographic thickness variationAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Luca Bondioli Abstract Qualitative and quantitative characterization through functional imaging of mineralized tissues is of potential value in the study of the odontoskeletal remains. This technique, widely developed in the medical field, allows the bi-dimensional, planar representation of some local morphometric properties, i.e., topographic thickness variation, of a three-dimensional object, such as a long bone shaft. Nonetheless, the use of morphometric maps is still limited in (paleo)anthropology, and their feasibility has not been adequately tested on fossil specimens. Using high-resolution microtomographic images, here we apply bi-dimensional virtual "unrolling" and synthetic thickness mapping techniques to compare cortical bone topographic variation across the shaft in a modern and a fossil human adult femur (the Magdalenian from Chancelade). We also test, for the first time, the possibility to virtually unroll and assess for dentine thickness variation in modern and fossil (the Neanderthal child from Roc de Marsal) human deciduous tooth roots. The analyses demonstrate the feasibility of using two-dimensional morphometric maps for the synthetic functional imaging and comparative biomechanical interpretation of cortical bone thickness variation in extant and fossil specimens and show the interest of using this technique also for the subtle characterization of root architecture and dentine topography. More specifically, our preliminary results support the use of virtual cartography as a tool for assessing to what extent internal root morphology is capable of responding to loading and directional stresses and strains in a predictable way. Am J Phys Anthropol, 2010. © 2010 Wiley-Liss, Inc. [source] Sweep-based Freeform DeformationsCOMPUTER GRAPHICS FORUM, Issue 3 2006Seung-Hyun Yoon We propose a sweep-based approach to the freeform deformation of three-dimensional objects. Instead of using a volume enclosing the whole object, we approximate only its deformable parts using sweep surfaces. The vertices on the object boundary are bound to the sweep surfaces and follow their deformation. Several sweep surfaces can be organized into a hierarchy so that they interact with each other in a controlled manner. Thus we can support intuitively plausible shape deformation of objects of arbitrary topology with multiple control handles. A sweep-based approach also provides important advantages such as volume preservation. We demonstrate the effectiveness of our technique in several examples. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computational Geometry and Object Modeling]: Curve, surface, solid, and object representations [source] New role for majors in Atta leafcutter antsECOLOGICAL ENTOMOLOGY, Issue 5 2007SOPHIE E. F. EVISON Abstract 1.,Atta (Hymenoptera: Formicidae) leafcutter ants display the most polymorphic worker caste system in ants, with different sizes specialising in different tasks. The largest workers (majors) have large, powerful mandibles and are mainly associated with colony defence. 2.,Majors were observed cutting fallen fruit and this phenomenon was investigated in the field by placing mango fruit near natural Atta laevigata and Atta sexdens colonies in São Paulo State, Brazil. 3.,Ants cutting the fruit were significantly heavier (mean = 49.1 mg, SD = 11.1 mg, n= 90) than the ants carrying the fruit back to the nest (mean = 20.9 mg, SD = 9.2 mg, n= 90). 4.,Fruit pieces cut by majors were small (mean = 15.9 mg), approximately half the weight of leaf pieces (mean = 28.5 mg) cut and carried by media foragers. It is hypothesised that it is more difficult to cut large pieces from three-dimensional objects, like fruit, compared to two-dimensional objects, like leaves, and that majors, with their longer mandibles, can cut fruit into larger pieces than medias. 5.,The study shows both a new role for Atta majors in foraging and a new example of task partitioning in the organisation of foraging. [source] Visualization of material stiffness in geomechanics analysisINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2006Donald C. Wotring Abstract This paper presents novel visualization techniques to simplify representation of the fourth-order material stiffness tensor as a set of three-dimensional geometric objects. Stiffness visualization aids in understanding the complex stiffness characteristics of highly non-linear constitutive models including modelled material anisotropy and loading path dependent stiffness variation. Stiffness visualization is relevant for understanding the relationship of material stiffness to global behaviour in the analysis of a boundary value problem. The spherical pulse stiffness visualization method, developed in the acoustics field, is extended to visualize stiffness of geomaterials using three three-dimensional objects. This method is limited to relatively simple constitutive models with symmetric stiffness matrices insensitive to loading magnitude and direction. A strain dependent stiffness visualization method is developed that allows the examination of material stiffness for a range of loading directions and is suitable for highly non-linear and path dependent material models. The proposed stiffness visualization can be represented as 3-D, 2-D and 1-D objects. The visualization technique is used to represent material stiffness and its evolution during simulated soil laboratory tests and deep excavation construction. Copyright © 2005 John Wiley & Sons, Ltd. [source] Imaging pharmaceutical tablets with optical coherence tomographyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2010Jakob M.A. Mauritz Abstract Optical coherence tomography (OCT) is a recently developed optical technique that produces depth profiles of three-dimensional objects. It is a nondestructive interferometric method responding to refractive index variation in the sample under study and can reach a penetration depth of a few millimetres. OCT employs near-infrared (NIR) light and therefore provides a link between NIR spectroscopy and Terahertz (THz) measurements that are often used to characterise tablets. In this article we assess the potential of OCT as a reliable and practical tool in the analysis of pharmaceutical tablets and coatings. A variety of tablets were tested with different shapes, formulations and coatings. We consider the origins of contrast in the obtained images and demonstrate that it correlates strongly with the expected tablet structure. The influence of absorption and scattering are considered for the wavelength ranges used. The results show that OCT is a promising diagnostic tool with an important role to play in the tablet and coating technologies. The high measurement speed of OCT and its relative ease of implementation make it also an attractive candidate technology for in-line quality control during manufacturing. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:385,391, 2010 [source] The power of thiol-ene chemistryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2010Matthew J. Kade Abstract As a tribute to Professor Charlie Hoyle, we take the opportunity to review the impact of thiol-ene chemistry on polymer and materials science over the past 5 years. During this time, a renaissance in thiol-ene chemistry has occurred with recent progress demonstrating its unique advantages when compared with traditional coupling and functionalization strategies. Additionally, the robust nature of thiol-ene chemistry allows for the preparation of well-defined materials with few structural limitations and synthetic requirements. To illustrate these features, the utility of thiol-ene reactions for network formation, polymer functionalization, dendrimer synthesis, and the decoration of three-dimensional objects is discussed. Also, the development of the closely related thiol-yne chemistry is described. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 743,750, 2010 [source] Assessing the affective feelings of two- and three-dimensional objectsCOLOR RESEARCH & APPLICATION, Issue 1 2009Wen-Yuan Lee Abstract The aim of this study is to investigate the impact of physical appearance attributes (in terms of color and shape) on our affective feelings of 2D and 3D objects. Twelve colors were studied, each consisting of 12 two-dimensional and 12 three-dimensional shapes. This resulted in 144 2D and 144 3D color-shape combinations. Each color-shape combination was assessed using 20 emotion scales in a viewing cabinet by a panel of observers with normal color vision. The results show that there are five underlying factors of these 20 scales, i.e., "activity," "weight," "heat," "softness," and "complexity". The first three factors were mainly related to color and the other two were linked with shape. © 2008 Wiley Periodicals, Inc. Col Res Appl, 34, 75,83, 2009. [source] | |||||||||||||