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Influence of seawater immersion in low energy impact behavior of a novel colombian fique fiber reinforced bio-resin laminate
Get PDFThis experimental work is aimed at the influence of seawater immersion in low impact energy behavior of a novel Colombian fique fiber reinforced bio-resin laminate. Such material was manufactured by vacuum infusion. The specimens were immersed in seawater during a bioactivity period of six months. Low energy impact tests were performed in order to obtain the penetration and perforation threshold according to energy profiles. The damage extent was characterized by means of Ultrasonics. Tensile stress tests were also performed and the breaking surfaces were analyzed by Scanning Electron Microscopy. The results revealed that the new biocomposite, after seawater immersion, has higher penetration and perforation thresholds than the biocomposite without immersion. Tensile test results show stiffness lost and increase of elongation at break. This behavior of the immersed biocomposite is due to a plasticization process of the material
Finite Element Prediction of the Tool Wear Influence in Ti6Al4V Machining
Get PDFTi6Al4 V is a titanium alloy widely used in the aeronautical industry and machining is often adopted to manufacture it. These parts must satisfy requirements specified by the customer. A crucial characteristic of aircraft machined parts is their reliability and, therefore, their fatigue life has to be mastered. In this context, the corresponding requirement concerns the surface integrity. This should be achieved by selecting adequate cutting parameters, which is actually not an immediate operation. The geometry of the tool will afterwards change during its life, what is more as Ti6Al4 V is known to be a hard-to-machine material. In this context, a finite element model is developed to highlight the influence of tool wear on fundamental variables like forces, temperatures, stresses,... and surface integrity (through plastic strains). The results should help to decide when it is time to replace the tool before altering the part and therefore not meet the specifications anymore
Analytical model to calculate radial forces in permanent-magnet synchronous machines
Get PDFIn permanent-magnet synchronous machines (PMSMs) electromagnetic forces are identified as the principal source of vibrations and noises. In this article, first of all the sources of magnetic forces in PMSMs are analyzed. Then, an analytical method for the calculation of radial forces on the base of the stator tooth created by electromagnetic sources in PMSMs is presented. Finally finite element method (FEM) is used to corroborate analytical results
Determination of the molecular diffusion coefficients in ternary mixtures by the sliding symmetric tubes technique
Get PDFA new analytical methodology has been developed to determine the diagonal and cross-diagonal molecular diffusion coefficients in ternary mixtures by the Sliding Symmetric Tubes technique. The analytical solution is tested in binary mixtures obtaining good agreement with the results of the literature. Results are presented for the ternary mixture formed by tetralin, isobutylbenzene, and dodecane with an equal mass fraction for all the components (1–1–1) which is held at 25 °C. Diagonal and cross-diagonal coefficients are determined for the three possible orders of components, in order to compare the results with those available in the literature. A comparison with published results shows a good agreement for the eigenvalues of the diffusion matrix, and a reasonable agreement for the diagonal molecular diffusion coefficients
On the support of multi-perspective process models variability for smart environments
Get PDFCloud service-based applications are to be adapted to serve multiple platforms and stakeholders. Atop of such services, Smart Green Buildings are fostering a plethora of processes within their sustainability life-cycle. This introduces a number of challenges, as how to support multiple perspectives of domain-specific variability and how to deal with large collections of related process variants. To tackle this, there is a need to handle multiperspective variability for processes. This paper introduces an approach to manage multi-perspective process variability by means of a meta-model and a modeling methodology, representing separately people and things variability perspectives in smart environments. Initial experimental results are also described, which indicate encouraging results for managing highly complex variability models
Numerical study of the heat transfer in wound woven wire matrix of a Stirling regenerator
Get PDFNusselt number correlation equations are numerically derived by characterizing the heat transfer phenomena through porous medium of both stacked and wound woven wire matrices of a Stirling engine regenerator over a specified range of Reynolds number, diameter and porosity. A finite volume method (FVM) based numerical approach is proposed and validated against well known experimentally obtained empirical correlations for a random stacking woven wire matrix, the most widely used due to fabrication issues, for Reynolds number up to 400. The results show that the numerically derived correlation equation corresponds well with the experimentally obtained correlations with less than 6% deviation with the exception of low Reynolds numbers. Once the numerical approach is validated, the study is further extended to characterize the heat transfer in a wound woven wire matrix model for a diameter range from 0.08 to 0.11 mm and a porosity range from 0.60 to 0.68 within the same Reynolds number range. Thus, the new correlation equations are numerically derived for different flow configurations of the Stirling engine regenerator. It is believed that the developed correlations can be applied with confidence as a cost effective solution to characterize and hence to optimize stacked and wound woven wire Stirling regenerator in the above specified ranges
Transevol - A Tool to Evolve Legacy Model Transformations by Example
Get PDFThe use of Model Driven Development (MDD) approach is increasing in industry. MDD approach raises the level of abstraction using models as main artefacts of software engineering processes. The development of model transformations is a critical step in MDD. Tasks for defining, specifying and maintaining model transformation rules can be complex in MDD. Model Transformation By Example (MTBE) approaches have been proposed to ease the development process of transformation rules. MTBE uses pair of input/output models to define the model transformation. Starting from pairs of example models the transformation rules are derived semi-automatically. The aim of our approach is to derive the adaptation operations that must be implemented in a legacy model transformation to fulfil a new transformation requirement. An MTBE approach and a tool to develop and evolve ATL transformation rules have been developed. Our approach derives the transformations operations automatically using execution traceability data and models differences. The developed MTBE approach can be applied to evolve legacy model transformations. A real case study is introduced to demonstrate the usefulness of the tool
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Get PDFMass effect on the soret coefficient in n-alkane mixtures
Get PDFWe have determined the Soret coefficient of different equimolar and non equimolar n-alkane mixtures from measurements of the molecular diffusion and thermal diffusion coefficients. It is shown that equimolar mixtures behave as isotopic-like mixtures in which only the mass effect contributes to the Soret effect. In non equimolar mixtures, a small linear dependence with the molar fraction is observed. Finally, we have obtained a new correlation, which allows the determination of the Soret coefficient of n-alkane mixtures using the data of viscosity, the thermal expansion coefficient of the pure components, and the density of the equimolar mixture