On the medial surface approximations of extrusions

Generating the medial surface for a general boundary representation model raises several difficulties. Problems might emerge from the complexity of the resulting equations, singularities caused by unforeseen relative boundary element positions and orientations, etc. The majority of the current algorithms are based on the topology of the boundary representation model and produce wireframes composed of straight lines regardless of the real medial surfaces. Many of the solids used in engineering can be represented by extrusions, delimited by a cross-section and an extrusion distance. This paper develops a fast and efficient method for creating the facetted approximations of the medial surfaces of extrusions generated by sweeping along the normal direction to the generating cross-sectio

advanced sensor signal feature extraction and pattern recognition for wire edm process monitoring

Wire electrical discharge machining (WEDM) is investigated in the perspective of zero-defect manufacturing with the scope to detect anomalous process conditions leading to typical defects generated during WEDM, i.e. the occurrence of lines and marks on the resulting workpiece surface. A multiple sensor monitoring system is employed to acquire high sampling rate sensorial data relative to signals of voltage and current in the gap between workpiece and wire electrode. An advanced signal processing methodology is implemented to extract and select the most relevant features useful to identify the undesired process conditions through a cognitive pattern recognition paradigm. (C) 2016 The Authors. Published by Elsevier B.V

An evaluation of H13 tool steel deformation in hot forging condition

Plastic deformation is one of the causes of failure of hot forging tools, where the tool deforms to such an extent that parts formed are no longer within dimensional tolerance. Therefore, deformation of H13 tool steel that leads to transformation of the microstructure after forging Inconel 718 at high temperature and load was investigated. For this investigation nonlinear continuum mechanics 3D FE simulation Deform software, Scanning Electron Microscope (SEM), Electron Backscatter Diffraction (EBSD) and Microhardness tests were used. The result of 3D Deform simulation shows high localised stress and high strain of 0.38 on the sharp edge of the tool. This is one of the main reasons behind tool failure as accumulation of strain during deformation at high temperature causes changes in microstructure. SEM results confirm the severe deformation and highlight three different zones of deformation, recrystallization, martensitic and transition between each zone within the microstructure. EBSD results show low angle boundaries of 1~15° which represents mainly the deformation zone and it is associated with different dislocation substructures caused by slip. Furthermore, misorientation angles 28-32° corresponds to special boundaries ∑39a which are believed were created during martensitic lattice transformation when some of the boundaries are not perfectly match the rest. These special boundaries transform to low angle boundaries. The high angle boundaries 58-60° corresponds to twin boundaries and their parent matrix

Methods to detect spatial biases in tracking studies caused by differential representativeness of individuals, populations and time

Este artículo contiene 20 páginas, 6 figuras, 4 tablas.Aim: Over the last decades, the study of movement through tracking data has grown exceeding the expectations of movement ecologists. This has posed new challenges, specifically when using individual tracking data to infer higher- level distributions (e.g. population and species). Sources of variability such as individual site fidelity (ISF), en-vironmental stochasticity over time, and space-use variability across species ranges must be considered, and their effects identified and corrected, to produce accurate estimates of spatial distribution using tracking data. Innovation: We developed R functions to detect the effect of these sources of vari-ability in the distribution of animal groups when inferred from individual tracking data. These procedures can be adapted for their use in most tracking datasets and tracking techniques. We demonstrated our procedures with simulated datasets and showed their applicability on a real-world dataset containing 1346 year- round migratory trips from 805 individuals of three closely related seabird species breeding in 34 colonies in the Mediterranean Sea and the Atlantic Ocean, spanning 10 years. We detected an effect of ISF in one of the colonies, but no effect of the environmental stochasticity on the distribution of birds for any of the species. We also identified among-colony variability in nonbreeding space use for one species, with significant effects of popu-lation size and longitude. Main conclusions: This work provides a useful, much- needed tool for researchers using animal tracking data to model species distributions or establish conservation measures. This methodology may be applied in studies using individual tracking data to accurately infer the distribution of a population or species and support the deline-ation of important areas for conservation based on tracking data. This step, designed to precede any analysis, has become increasingly relevant with the proliferation of studies using large tracking datasets that has accompanied the globalization process in science driving collaborations and tracking data sharing initiatives.We thank the following institutions for funding: EU H2020 pro-gramme through grant 634495; Seventh Framework Programme (Research Executive Agency) through Marie Curie Career Integration Grant 618841 (FP7-PEOPLE-2013- CIG); ESFRI LifeWatch Project; LIFE programme of the European Commission through projects LIFE10 NAT/MT090 and LIFE11 NAT/IT/000093; Ministerio de Ciencia e Innovación/Ministerio de Economia y Competitividad (Spain) through projects CGL2009- 11278/BOS, CGL2013-42585-P, C G L 2 0 1 3 - 4 2 2 0 3 - R , C G L 2 0 16 - 7 8 5 3 0 - R a n d C G L 2 0 17- 8 52 10 - P ; Organismo Autónomo de Parques Nacionales (Spain) through pro-ject 1248/2014; Fundação para a Ciência e a Tecnologia (MCTES, Portugal) through projects MARE-UID/MAR/04292/2019; IF/00502/2013/CP1186/CT0003, PTDC/BIA-ANM/3743/2014, PTDC/MAR-PRO/0929/2014, UID/AMB/50017/2019 and UIDP/50017/2020 + UIDB/50017/2020 (to CESAM); Office Français de la Biodiversité (France), through the Programme PACOMM, Natura2000 en mer; Hellenic Bird Ringing Centre; MSDEC (Malta). VMP was supported by pre-doctoral contract BES-2014- 068025 of the Spanish Ministerio de Industria, Economía y Competitividad; MM by grant SFRH/BPD/47047/2008 from the Portuguese Foundation for Science and Technology; JMRG by Ph.D. grant AP2009-2163 from the Spanish Ministerio de Educación; GDO and MMü by Ornis italica and by the Regione Siciliana and Assessorato Risorse Agricole e Alimentari thoriugh a grant to the Ringing Unit of Palermo; VHP by grant SFRH/BPD/85024/2012 from the Portuguese Foundation for Science and Technology; VN by grant SFRH/BPD/88914/2012 from the Portuguese Foundation for Science and Technology; and JN by the Spanish National Programme Ramón y Cajal (RYC-2015- 17809); GK and SX were partially funded by the Operational Program “Environment and Sustainable Development” (EPPERAA) of the National Strategic Reference Framework (NSRF) 2007-2013, co- financed by the ERDF and Greek EDP; FdF by a Ph.D. grant from the Coordination for the Improvement of Higher Education Personnel (CAPES—Brazilian government agency; Bex Process 1307/13-4); ZZ by a PhD grant from the University of Barcelona (APIF/2012); MCF by a PhD grant from the University of Barcelona; and RR by post-doctoral contracts of the PLEAMAR programme from MINECO and Fundación Biodiversidad (2017/2349), and Ministerio de Ciencia, in-novación y Universidades (RYC-2017- 22055). This publication is part of the project I+D+i/PID2020-117155GB-I00, funded by MCIN/ AEI/10.13039/501100011033.Peer reviewe