Search results for "Planetary Science"
showing 10 items of 4367 documents
On the Use of a GPU-Accelerated Mobile Device Processor for Sound Source Localization
2017
Abstract The growing interest to incorporate new features into mobile devices has increased the number of signal processing applications running over processors designed for mobile computing. A challenging signal processing field is acoustic source localization, which is attractive for applications such as automatic camera steering systems, human-machine interfaces, video gaming or audio surveillance. In this context, the emergence of systems-on-chip (SoC) that contain a small graphics accelerator (or GPU), contributes a notable increment of the computational capacity while partially retaining the appealing low-power consumption of embedded systems. This is the case, for example, of the Sam…
Hpdm : A Hybrid Pseudonym Distribution Method for Vehicular Ad-Hoc Networks
2016
Abstract Protecting the location privacy of drivers is still one of the main challenges in Vehicular Ad-hoc Networks (VANETs). The changing of pseudonym is commonly accepted as a solution to this problem. The pseudonyms represent fake vehicle identifiers. Roadside Units (RSUs) play a central role in the existing pseudonyms distribution solutions. Indeed, the VANET area should totally be covered by RSUs in order to satisfy the demand of vehicles in terms of pseudonyms. However, the total coverage is costly and hard to be achieved, especially in the first phase of VANETs deployment. In addition, RSUs could be overloaded due to the large number of pseudonyms requests that could be received fro…
Análisis para la Implementación del Sistema de Gestión de Calidad y del Sistema de Gestión Ambiental para el Laboratorio de Análisis Instrumental de …
2019
El Laboratorio de Análisis Instrumental ubicado en el 5to piso del Edificio No. 17 de la Escuela Politécnica Nacional brinda servicios de análisis de gases de pozo, biogás, biocidas, solventes, vidrios laminados y templados, entre otros; no obstante, no cuenta con un sistema integrado de Gestión que incluya la ISO 9001:2015 ni ISO 14001:2015, los cuales deberían ser una base fundamental a fin de permitir una dirección basada en la optimización de procesos con una disminución de los impactos ambientales que puede generar cualquier empresa. Con estos antecedentes, el presente trabajo tiene por objetivo desarrollar un mecanismo para implementación de un SIG y que vaya acorde a la normativa ISO…
Using the Analytic Hierarchy Process (AHP) and fuzzy logic to evaluate the possibility of introducing single point incremental forming on industrial …
2018
Abstract Single point incremental forming (SPIF) is a promising forming process, yet not entirely accepted and implemented on industrial scale, due to several reasons, presented in the paper. The approach presented here develops an evaluation method for the degree of its industrial implementation. Several factors which will favor the industrial implementation of ASPIF are identified and their weights are hierarchized by means of AHP. To assess the robustness of the AHP, a sensitivity analysis was also presented. Furthermore, a fuzzy inference system was built, having as output the degree of industrial implementation of SPIF.
Using the Analytic Hierarchy Process (AHP) in Evaluating the Decision of Moving to a Manufacturing Process Based Upon Continuous 5 Axes CNC Machine-t…
2016
Abstract This paper represents the second part of the work described in the paper with the title “Decision-making tool for moving from 3-axes to 5-axes CNC machine-tool”. The problem of using either 3 axes CNC machine-tools or 5 axes CNC machine tools was presented in the first part, together with a fuzzy logic based decision support tool. This time, an AHP approach is used in order to evaluate the decision of moving to a manufacturing process based upon 5 axes machine tools. Three variants were taken into consideration and analysed. The consistency of the proposed approach was evaluated and a sensitivity analysis was also introduced.
On the impact of recycling strategies on energy demand and CO2 emissions when manufacturing Al-based components
2016
Abstract The industrial world is facing the challenge of reducing emissions by means of energy- and resource-efficient manufacturing strategies. In some cases, the exerted emissions and the energy demands related to conventional manufacturing processes are not as intensive as those required to extract and produce the raw materials of which the workpieces are made. Therefore, the consciousness of the impact of material usage and the eco-informed choice of the end-of-life scenarios are both needed in view of sustainable development. Aim of this paper is to offer a contribution to a better understanding of the environmental impact of forming and machining processes, for the production of Al-ba…
Microstructure and mechanical properties of dissimilar Ti/Nb/Cu/steel laser joints
2020
Abstract The absence of intermetallic phases in Fe/Cu, Cu/Nb and Nb/Ti binary systems opens the possibility to obtain reliable joints between titanium alloys and steels by using a multimaterial copper/niobium insert. Continuous Yb:YAG laser welding of 1 mm thick titanium and 316L stainless steel plates through niobium/copper multimaterial insert was performed. The use of a 100 µm laser beam allowed producing isolated molten zones and thus completely avoiding the formation of brittle intermetallic phases, according to SEM and XRD analysis. The effect of energy per unit length applied to the niobium/copper welds on the mixing process and mechanical properties of the joints was investigated. A…
On the optimization of the cutting conditions for an improved corrosion resistance of OFHC copper
2018
International audience; Machining has a particular impact on the surface integrity and on corrosion resistance of components. In fact, material removal induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface that alter the electrochemical behavior of the material, and so the aging process. In this study, oxygen free high conductivity copper (OFHC) has machined under orthogonal cutting conditions using uncoated cemented carbide tools. Then, the corrosion resistance in 0.1 M NaCl salt fog atmosphere of the machined samples is analyzed. Finally, the optimal cutting conditions, including the tool geometry, for an improved corrosion resistance a…
Direct laser welding of pure titanium to austenitic stainless steel
2018
Abstract Direct butt joining of pure titanium to 316L stainless steel with continuous Yb:YAG laser was performed with variation of the beam offset from joint line. Mechanical properties of samples were evaluated by tensile tests and three-point flexural tests. The fractured surfaces and cross sections of welds were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Tensile properties of welds were strongly determined by the beam offset from joint line and are well described by Weibull statistics. Ultimate tensile strength of 174 ± 69 MPa and ultimate flexural strength of 297 ± 48 MPa were obtained. Brittle fracture took place in…
Laser-assisted narrow gap arc welding of an 18MND5 steel thick plate
2020
Abstract Narrow gap arc welding is a common solution for the welding of thick structures. In this study, a defocused laser beam is used to pre-melt the narrow gap walls in front of an arc-welding bath. Such a welding configuration can be referred to a hybrid welding configuration. In the present work, a particular attention is given to evaluation of the interaction between an arc plasma and a defocused laser beam. High-speed imaging of the metal transfer through arc plasma is achieved thanks to a diode laser illumination system. Electrical arc parameters are logged, synchronously, in order to perform a correlation analysis and to make a diagnosis of the interaction level between laser beam …