Search results for "mechanical engineering"
showing 10 items of 4245 documents
Synchrotron x-ray transmission measurements and modeling of filters investigated for Athena
2020
International audience; Advanced Telescope for High-Energy Astrophysics is a large-class astrophysics space mission selected by the European Space Agency to study the theme "Hot and Energetic Universe." The mission essentially consists of a large effective area x-ray telescope and two detectors: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). Both instruments require filters to shield from out-of-band radiation while providing high transparency to x-rays. The mission is presently in phase B; thus, to consolidate the preliminary design, investigated filter materials need to be properly characterized by experimental test campaigns. We report results from high-resolution…
Heavy-Ion-Induced Defects in Degraded SiC Power MOSFETs
2023
Cathodoluminescence spectroscopy is used to investigate the formation of point- and extended defects in SiC power MOSFETs exposed to heavy-ions. Devices showing single event leakage current (SELC) effects are analysed and compared to pristine samples. Common luminescence peaks of defect centers localized in the thermal-SiO2 are identified, together with peaks at the characteristic wavelength of extended defects.
Operator Revenue Analysis for Device-to-Device Communications Overlaying Cellular Network
2018
Device-to-device (D2D) communications has recently gathered significant research interest due to its efficient utilization of already depleting wireless spectrum. In this article, we considered a scenario where D2D users communicate in the presence of cellular users in an overlay network setup. In order to analyze the revenue of service providers in monetary terms, the paper provides exact expressions of operator profit for both D2D and cellular users. More specifically, we take into account different network parameters including user density, transmit power and channel variations to understand their impact on the total revenue of the operator. Finally, we derive the balancing value of freq…
Multicriteria evaluation of alternatives for remote monitoring systems of municipal buildings
2014
Abstract Conservation of natural resources drives municipalities to monitor their heat, power and water consumption more accurately. The objective of this study was to evaluate different implementation possibilities for remote monitoring systems for the municipal buildings of two medium-sized municipalities, Hollola and Nastola in Southern Finland. Four different alternatives were considered: (1) a system by an external service provider, (2) a system provided by the local energy distribution company, (3) a system built by the municipalities themselves, and (4) using the current manual system but with more frequent data collection. The alternatives were evaluated in terms of multiple functio…
Contributions to risk injury evaluation of human skin contact caused by welding technology in mechanical engineering a company
2017
Assembly by welding is a very important pollutant technological process, mainly of the atmosphere and soil. The formation of gas in welding process is the result of electrodes, fluxes burning, formation of fused bath and welded seam. A large number of human operators feels different adverse effects on health. Most problems appears in respiratory system and include bronchitis, respiratory irritation, fever caused by smoke, changes in lung function, decreased immunity to infection and a possible increase of lung cancer risk. Very little information are available about effects on the organism and skin after exposure to fumes from welding, therefore. In this order, this paper do a risk assessme…
The thermal performances of historic masonry: In-situ measurements of thermal conductance on calcarenite stone walls in Palermo
2018
Abstract Rich literature explores materials and construction techniques of historic buildings, but limited information is available about the thermal and hygrometric features of their envelope. Nevertheless, accurate hygrothermal data are essential for identifying effective energy upgrade measures, which must be compatible with the conservation of the architectural heritage. In order to fill this gap, it is necessary to refer to local contexts, where the variety of historic buildings is limited and their material and construction features are comparable. This paper focuses on historic masonry walls and discusses the results of twenty in-situ measurements of thermal conductance, performed al…
Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future.
2020
As the need for green and effective utilization of energy continues to grow, the advancements in the energy and power electronics industry are constantly driven by this need, as both industries are intertwined for obvious reasons. The developments in the power electronics industry has over the years hinged on the progress of the semiconductor device industry. The semiconductor device industry could be said to be on the edge of a turn into a new era, a paradigm shift from the conventional silicon devices to the wide band gap semiconductor technologies. While a lot of work is being done in research and manufacturing sectors, it is important to look back at the past, evaluate the current progr…
Optimisation through offshore – between reality and legality
2021
The study highlights the complete image of the characteristics regarding offshore areas, by taking into account the perspective to deploy new measures of fiscal transparency. The importance of such areas stems from the fact that world economies lose important sums of money, every year by default of taxes. This happens as a consequence of corporative international abuse of fiscal evasion and the relocation of the profit made by big companies. The sums resulted from erosion of national taxation bases, from fiscal evasion and fraud and other infringements connected with fiscal evasion (are often being transferred to offshore companies so that their illegal characteristics gets lost and after t…
Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes
2021
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of th…
The mechanically based non-local elasticity: an overview of main results and future challenges
2013
The mechanically based non-local elasticity has been used, recently, in wider and wider engineering applications involving small-size devices and/or materials with marked microstructures. The key feature of the model involves the presence of non-local effects as additional body forces acting on material masses and depending on their relative displacements. An overview of the main results of the theory is reported in this paper.