Search results for "Computer-aided design"
showing 10 items of 312 documents
A spline-based non-linear diffeomorphism for multimodal prostate registration.
2012
This paper presents a novel method for non-rigid registration of transrectal ultrasound and magnetic resonance prostate images based on a non-linear regularized framework of point correspondences obtained from a statistical measure of shape-contexts. The segmented prostate shapes are represented by shape-contexts and the Bhattacharyya distance between the shape representations is used to find the point correspondences between the 2D fixed and moving images. The registration method involves parametric estimation of the non-linear diffeomorphism between the multimodal images and has its basis in solving a set of non-linear equations of thin-plate splines. The solution is obtained as the least…
Evaluation of prostate segmentation algorithms for MRI: The PROMISE12 challenge
2014
Contains fulltext : 137969.pdf (Publisher’s version ) (Open Access) Prostate MRI image segmentation has been an area of intense research due to the increased use of MRI as a modality for the clinical workup of prostate cancer. Segmentation is useful for various tasks, e.g. to accurately localize prostate boundaries for radiotherapy or to initialize multi-modal registration algorithms. In the past, it has been difficult for research groups to evaluate prostate segmentation algorithms on multi-center, multi-vendor and multi-protocol data. Especially because we are dealing with MR images, image appearance, resolution and the presence of artifacts are affected by differences in scanners and/or …
Zirconia Removable Telescopic Dentures Retained on Teeth or Implants for Maxilla Rehabilitation. Three-Year Observation of Three Cases
2010
Abstract This report addresses maxillary restoration with removable telescopic crown-retained palatal free dentures. One patient with 7 natural teeth (PERIO), a second patient with 6 dental implants (IMPL), and a third patient with 2 natural teeth and 4 dental implants (IMPL-PERIO) were treated. Zirconia copings for natural teeth and individual zirconia implant abutments were fabricated in CAD/CAM and used as primary crowns. Electroformed gold copings were used as secondary telescopes. All maxilla supraconstructions were fabricated with zirconia and CAD/CAM. Patients were monitored during a 3-year period; all teeth and implants survived, and no biological or mechanical complications occurre…
A Theoretical Approach to the Shift Mechanics of Rubber Belt Variators
2008
This paper proposes a theoretical description of the mechanical behavior of rubber belt variators during the speed ratio shift. Comparing with the steady operation, the mass conservation of the belt is completely reformulated considering an elementary dihedral control volume between two planes through the pulley axis and balancing the inside mass variation with the total mass flux through the control surface. On the other hand, the belt equilibrium conditions are similar to the steady case, as the inertia forces due to the shifting motion are negligible with respect to the other forces. Assuming a one-dimensional belt model, it is shown that adhesive regions may appear inside the arc of con…
Features of randomized electric-field assisted domain inversion in lithium tantalate
2011
We report on bulk and guided-wave second-harmonic generation via random Quasi-Phase-Matching in Lithium Tantalate. By acquiring the far-field profiles at several wavelengths, we extract statistical information on the distribution of the quadratic nonlinearity as well as its average period, both at the surface and in the bulk of the sample. By investigating the distribution in the two regions we demonstrate a non-invasive approach to the study of poling dynamics.
Octave-spanning ultraflat supercontinuum with soft-glass photonic crystal fibers
2009
We theoretically identify some photonic-crystal-fiber structures, made up of soft glass, that generate ultrawide (over an octave) and very smooth supercontinuum spectra when illuminated with femtosecond pulsed light. The design of the fiber geometry in order to reach a nearly ultraflattened normal dispersion behavior is crucial to accomplish the above goal. Our numerical simulations reveal that these supercontinuum sources show high stability and no significant changes are detected even for fairly large variations of the incident pulse. Ministerio de Ciencia e Innovación (TEC2008-05490) and Generalitat Valenciana (GV/2007/043).
Study of the glow curves of TLD exposed to thermal neutrons.
2007
The glow curves of thermoluminescent dosimeters (TLD600, TLD700 and MCP), exposed to a mixed field of thermal neutrons and gamma photons are analysed. The fluence values of thermal neutrons used, comparable with those used in radiotherapy, allow one to define the reliability of the TLDs, in particular the most sensitive MCP, in this radiation field and to get information on the dose absorbed values. The glow curves obtained have been deconvoluted using general order kinetics and the observed differences for the different LET components have been analysed. In particular, the ratio of the n(0) parameter of two different peaks seems to allow to discriminate the different contributions of neutr…
The development of nature-inspired gripping system of a flat CFRP strip for stress-ribbon structural layout
2021
Abstract The elegant stress-ribbon systems are efficient in pedestrian bridges and long-span roofs. Numerous studies defined corrosion of the steel ribbons as the main drawback of these structures. Unidirectional carbon fiber-reinforced polymer (CFRP) is a promising alternative to steel because of lightweight, high strength, and excellent corrosion and fatigue resistance. However, the application of CFRP materials faced severe problems due to the construction of the anchorage joints, which must resist tremendous axial forces acting in the stress-ribbons. Conventional techniques, suitable for the typical design of the strips made from anisotropic material such as steel, are not useful for СF…
Dynamic doping in bright and stable light emitting electrochemical cells.
2013
By using fast current density and luminance versus voltage (JL-V) analysis the device operation of sandwiched light emitting electrochemical cells (LECs) during their normal voltage driving operation mode is studied. In LECs the application of a voltage results in the movement of ions changing the state of the device, as a result the JL-V scans need to be performed fast and meet certain conditions to be meaningful. Space-charge limited current behavior is observed once the injection barriers are overcome. The increase of the current density after this point imply that the effective thickness of the devices is reduced which indicates the formation of more conductive regions adjacent to the e…
Numerical Procedure For Residual Stresses Prediction In Friction Stir Welding
2011
The prediction of residual stresses is a relevant and, under many points of view, still open issue for a proper welding process design. In the present paper a 3D FE model, with general validity for different joint configurations, was used to simulate the Friction Stir Welding (FSW) process of butt joints through a single block approach. The model is able to predict the residual stresses by considering thermal actions only, thanks to a new time efficient approach. A good agreement between calculated and experimentally measured data was found; the effectiveness of the presented numerical procedure was evaluated by comparing the calculation times of the proposed method with the ones of already…