Search results for "STIR"
showing 10 items of 426 documents
The syndrome "basses richesses" of sugar beet in France is associated with different pathogen types and insect vectors
2007
International audience; The syndrome “basses richesses” (SBR) of sugar beet in France is associated with two phloem-restricted uncultivable bacteria: a stolbur phytoplasma and a y-3 proteobacteria. The known vector of proteobacteria is a cixiid planthopper, Pentastiridius leporinus (Hemiptera Cixiidae), formerly shown to transmit both the prokaryotes. The role of P. leporinus and of two other planthopper species, Cixius wagneri and Hyalesthes obsoletus, in spreading the two pathogens to sugar beet were compared and quantified. Because of its abundance and high infection rates with proteobacterium, P. leporinus was confirmed to be the economic vector of SBR disease. P. leporinus and C. wagne…
A Numerical Optimisation of a Stirling Engine
2011
International audience; A zero dimensional finite-time thermodynamic, three zones model of a generic Stirling engine has been developed and experimentally validated. Taking into account time-dependant heat transfers and losses, the model calculates the evolution of gas temperature, mass and pressure in each zone.
Material flow analysis in dissimilar friction stir welding of AA2024 and Ti6Al4V butt joints
2016
The complex material flow occurring during the weld of dissimilar AA2024 to Ti6Al4V butt and lap joints was highlighted through a dedicated numerical model able to take into account the effects of the different materials as well as the phase transformation of the used titanium alloy.
Modeling of the plastic characteristics of AA6082 for the friction stir welding process
2015
Focus of this paper is to model the plastic forming behavior of AA6082, in order to develop the numerical FE analysis of the friction stir welding processes and the simulation of subsequent forming processes. During the friction stir welding process, the temperatures reached can range up to 500 °C and have a fundamental role for the correct performance of the process, so the material data has to show a temperature dependency. Because of the tool rotation a strain rate sensitivity of the material has to be respected as well. In this context, the general material characteristics of AA6082 were first identified for different stress states. For the uniaxial state the standard PuD-Al used in the…
Meidän herramme ja meidän häviäjämme
2019
Luokkakonfliktin ytimessä ovat arvot. Virossa konservatiivisen kansanpuolue EKREn ja sosiaalidemokraattisen SDE:n välisessä konfliktissa kansaa jaetaan herroihin ja häviäjiin. nonPeerReviewed
Influencia de la autoliberación miofascial versus estiramientos estáticos en un programa de entrenamiento de fuerza en miembros inferiores.
2016
El uso de diferentes estrategias en el calentamiento y recuperación de los deportistas son habitualmente utilizadas en la práctica regular de cualquier actividad físico-deportiva, ya sea en un simple entrenamiento o en una prueba de competición, teniendo como fin principal el conseguir las mejores adaptaciones o resultados en cada una de ellas. Hay numerosos estudios que pretenden averiguar las combinaciones más adecuadas para lograr dichos cambios físicos entre el reposo inicial de un individuo y el trabajo físico principal que pretende desarrollar, así como desde esta situación de trabajo físico a la de reposo final, siendo la activación inicial y la recuperación posterior a través de una…
Frames and Contradictions of the Journalistic Profession
2016
In his essay The Soul of Man Under Socialism Oscar Wilde wrote: ‘In old days men had the rack. Now they have the press’. His words reflect the noticeable power the press had acquired in society already by the end of the 19th century. Journalism began to obtain characteristics of a profession, developing from craft towards an occupation demanding certain specific qualities.
Using a neural network for qualitative and quantitative predictions of weld integrity in solid bonding dominated processes
2014
Solid-state bonding occurs in several manufacturing processes, as Friction Stir Welding, Porthole Die Extrusion and Roll Bonding. Proper conditions of pressure, temperature, strain and strain rate are needed in order to get effective bonding in the final component. In the paper, a neural network is set up, trained and used to predict the bonding occurrence starting from the results of specific numerical models developed for each process. The Plata-Piwnik criterion was used in order to define a quantitative parameter taking into account the effectiveness of the bonding. Excellent predictive capability of the network is obtained for each process.
Analytical bonding criteria for joint integrity prediction in friction stir welding of aluminum alloys
2014
Abstract In this study, two bonding criteria, previously used for porthole die extrusion, are applied to FSW starting from the local value of the main field variables calculated through a specifically developed 3D numerical model of the process. Their applicability and effectiveness have been assessed through an experimental and numerical campaign carried out with the main process parameters varying in a wide range. The pressure–time–flow criterion was demonstrated to be better suited for FSW processes when large welding speed is used.
Solid State Joining of Thin Hybrid Sandwiches Made of Steel and Polymer: a Feasibility Study
2020
Abstract The growing demand for more environmentally friendly vehicles has led to an increased use of light materials in the transportation industry with the aim to reduce structural weight, fuel consumption, and gas emissions, thereby boosting cost-effectiveness and recyclable properties. Complex multi-material steel-based components would allow to improve mechanical properties and minimize weight even further. In particular, new sandwich materials made by steel outer skins and a polymeric internal layer seems very promising for obtaining mechanical performance and lightness at the same time. Unfortunately, traditional welding techniques, like arc welding, laser welding, and resistance spo…