Surface reconstruction using multiple light sources and perspective projection

This paper presents a method to recover 3D geometry of Lambertian surfaces by using multiple images taken from the same view point and with the scene illuminated from different positions. This approach differs from Stereo Photometry in that it considers the light source at a finite distance from the object and the perspective projection in image formation. The proposed model allows local solution and recovery of 3D coordinates, in addition to surface orientation. A procedure to calibrate the light sources is also presented. Results of the application of the algorithm to synthetic images are shown.

Structure, characterization and near-infrared emission of a novel 6-connected uninodal 3D network of Nd(III) containing 2,5-thiophenedicarboxylate anion

The novel coordination polymer with the formula {[Nd2(2,5-tdc)3(dmf)2(H2O)2].dmf.H2O}n (2,5-tdc2-=2,5-thiophedicarboxylate anion and dmf=dimethylformamide) has been synthesized and characterized by thermal analysis (TG/DTA), vibrational spectroscopy (FTIR) and single crystal X-ray diffraction analysis (XRD). Structure analysis reveals that Nd(III) ions show dicapped trigonal prism coordination geometry. The 2,5-tdc2- ligands connect four Nd(III) centers, adopting (κ1 - κ1) - (κ1 - κ1) - μ4 coordination mode, generating an interesting 6-connected uninodal 3D network. Photophysical properties were studied using diffuse reflectance spectroscopy (DR) and excitation/emission spectra. The photoluminescence data show the near infrared emission (NIR) with the characteristic 4F3/2→4IJ (J=9/2, 11/2 and 13/2) transitions of Nd(III) ion, indicating that 2,5-tdc2- is able to act as a sensitizer for emission in NIR region. © 2013 Elsevier B.V.

Representação e armazenamento de dados cadastrais 3D em banco de dados geográficos

Pós-graduação em Ciências Cartográficas - FCT

Automatic Orientation of Multi-Scale Terrestrial Images for 3D Reconstruction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modelo petrofísico 3D do Arenito Namorado no Campo de Namorado - Bacia de Campos, RJ

The Namorado Oil Field represents the beginning of the oil exploration in Brazil, in the 70s, and it is still a subject of researches because the importance of this turbidite sandstone in the brazilian oil production. The Namorado’s production level was denominated “Namorado sandstone”, it is composed by turbidite sandstone deposited during the Albian-Cenomanian. In order to define the structural geometry of the main reservoir, geological and geophysical tools like RECON and Geographix (Prizm – Seisvision) softwares were used, and its application was focused on geological facies analysis, for that propose well logs, seismic interpretation and petrophysical calculations were applied. Along this work 15 vertical wells were used and the facies reservoirs were mapped of along the oil field; it is important to mentioned that the all the facies were calibrated by the correlation rock vs log profile, and 12 reservoir-levels (NA-1, NA-2, NA-3, NA-4, NA-5, NA-6, NA-7, NA-8, NA-9, NA-10, NA-11 e NA-12) were recognized and interpreted. Stratigraphic sections (NE-SW and NW-SE) were also built based on stratigraphic well correlation of each interpreted level, and seismic interpretation (pseudo-3D seismic data) on the southeastern portion of the oil field. As results it was interpreted on two- and three-dimensional maps that the deposition reservoir’s levels are hight controlled by normal faults systems. This research also shows attribute maps interpretation and its relationship with the selection of the reservoir attribute represented on it. Finally the data integration of stratigraphic, geophysical and petrophysical calculations lets us the possibility of obtain a detail geological/petrophysical 3D model of the main reservoir levels of “Namorado sandstone” inside the oil/gás field

Finite element analysis of the influence of geometry and design of zirconia crowns on stress distribution

Purpose: To evaluate the influence of the geometry and design of prosthetic crown preparations on stress distribution in compression tests, using finite element analysis (FEA). Materials and Methods: Six combinations of 3D drawings of all-ceramic crowns (yttria-stabilized zirconia framework and porcelain veneer) were evaluated: F, flat preparation and simplified crown; FC, flat preparation and crown with contact point; FCM, flat preparation and modified crown; A, anatomical preparation and simplified anatomical crown framework; AC, anatomical preparation and crown with contact point; and ACM, anatomical preparation and modified crown. Bonded contact types at all interfaces with the mesh were assigned, and the material properties used were according to the literature. A 200 N vertical load was applied at the center of each model. The maximum principal stresses were quantitatively and qualitatively analyzed. Results: The highest values of tensile stress were observed at the interface between the ceramics in the region under the load application for the simplified models (F and A). Reductions in stress values were observed for the model with the anatomical preparation and modified infrastructure (ACM). The stress distribution in the flat models was similar to that of their respective anatomical models. Conclusions: The modified design of the zirconia coping reduces the stress concentration at the interface with the veneer ceramic, and the simplified preparation can exert a stress distribution similar to that of the anatomical preparation at and near the load point, when load is applied to the center of the crown.

Superconducting properties of a parallelepiped mesoscopic superconductor: a comparative study between the 2D and 3D Ginzburg-Landau models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A visualização no ensino de geometria com o Geogebra 3D

This research presents an investigation about the relevance of visualization in teaching geometry. Our interest turns to analyzing the use of technology in teaching geometry, seeking to highlight their contribution to learning. The students of today - second decade of the 21st century - require that, each time more, the school move towards the integration of technologies for teaching since tablets, smartphone, netbook, notebook are items present on daily life of most students. Thereby, we investigate, taking the phenomenological orientation, the potential of educational software, especially the Geogebra 3D, directed at teaching math and favoring the work with the geometry viewing. At work we bring some theoretical considerations about the importance of viewing for the geometric learning and the use of technologies. We build an intervention proposal for the classroom of the 7th year of elementary school with tasks aimed at visual exploration and allow the teacher to work the concept of volume of geometric solids

A low-cost 3D reconstruction system using a single-shot projection of a pattern matrix

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of a bounded high order upwind scheme for 3D incompressible free surface flow computations

fit the context of normalized variable formulation (NVF) of Leonard and total variation diminishing (TVD) constraints of Harten. this paper presents an extension of it previous work by the authors for solving unsteady incompressible flow problems. The main contributions of the paper are threefold. First, it presents the results of the development and implementation of a bounded high order upwind adaptative QUICKEST scheme in the 3D robust code (Freeflow), for the numerical solution of the full incompressible Navier-Stokes equations. Second, it reports numerical simulation results for 1D hock tube problem, 2D impinging jet and 2D/3D broken clam flows. Furthermore, these results are compared with existing analytical and experimental data. and third, it presents the application of the numerical method for solving 3D free surface flow problems. (C) 2007 IMACS. Published by Elsevier B.V. All rights reserved,

Case study: a 3D resistivity and induced polarization imaging from downstream a waste disposal site in Brazil

A contaminated site from a downstream municipal solid waste disposal site in Brazil was investigated by using a 3D resistivity and induced polarization (IP) imaging technique. This investigation purpose was to detect and delineate contamination plume produced by wastes. The area was selected based on previous geophysical investigations, and chemical analyses carried out in the site, indicating the presence of a contamination plume in the area. Resistivity model has successfully imaged waste presence (rho < 20 Omega m), water table depth, and groundwater flow direction. A conductive anomaly (rho < 20 Omega m) outside wastes placement was interpreted as a contamination plume. Chargeability model was also able to imaging waste presence (m > 31 mV/V), water table depth, and groundwater flow direction. A higher chargeability zone (m > 31 mV/V) outside wastes placement and following conductive anomaly was interpreted as a contamination plume. Normalized chargeability (MN = m/rho) confirmed polarizable zone, which could be an effect of a salinity increase (contamination plume), and the clay presence in the environment.

Investigation of Plasma Immersion Ion Implantation Process in Magnetic Mirror Geometry

Plasma immersion ion implantation (PIII) with low external magnetic field has been investigated both numerically and experimentally. The static magnetic field considered is essentially nonuniform and is generated by two magnetic coils installed outside the vacuum chamber. Experiments have been conducted to investigate the effect of two of the most important PIII parameters: target voltage and gas pressure. In that context, it was found that the current density increased when the external parameters were varied. Later, the PIII process was analyzed numerically using the 2.5-D computer code KARAT. The numerical results show that the system of crossed E x B fields enhances the PIII process. The simulation showed an increase of the plasma density around the target under the operating and design conditions considered. Consequently, an increase of the ion current density on the target was observed. All these results are explained through the mechanism of gas ionization by collisions with electrons drifting in crossed E x B fields.

Boundary identification criteria and geometry analysis of Al 7050 stretch zone from elevation profiles

This article describes the development of a method for analysis of the shape of the stretch zone surface based on parallax measurement theory and using digital image processing techniques. Accurate criteria for the definition of the boundaries of the stretch zone are established from profiles of fracture surfaces obtained from crack tip opening displacement tests on Al-7050 alloy samples. The elevation profiles behavior analysis is based on stretch zone width and height parameters. It is concluded that the geometry of the stretch zone profiles under plane strain conditions can be described by a semi-parabolic relationship. (C) Elsevier B.V., 1999. All rights reserved.

Differential geometry of intersection curves in R(4) of three implicit surfaces

We present algorithms for computing the differential geometry properties of intersection Curves of three implicit surfaces in R(4), using the implicit function theorem and generalizing the method of X. Ye and T. Maekawa for 4-dimension. We derive t, n, b(1), b(2) vectors and curvatures (k(1), k(2), k(3)) for transversal intersections of the intersection problem. (C) 2008 Elsevier B.V. All rights reserved.