Search results for "STIR"
showing 10 items of 426 documents
Friction Based Solid State Welding Processes
2012
In the last decade the industrial use of solid state welding processes based on frictional forces work decaying into heat is continuously increasing due to their strong advantages with respect to traditional fusion techniques. Several advances have been proposed by the scientific community regarding process mechanics, material flow and also the computer aided engineering of the operation with the aim to maximize the mechanical performances of the welded joints. In the paper Friction Stir Welding (FSW) and Linear Friction Welding (LFW) operations are considered and a review of the most relevant research issues and results is provided.
Outlining the Limits of Friction Stir Consolidation as Used as an Aluminum Alloys Recycling Approach
2021
Friction stir consolidation (FSC) is a solid-state process that recycles metal scraps economically and eco-friendly compared to the conventional melting method. The process parameters especially processing time and rotational speed, have a crucial role in achieving a sound disc during FSC. The current study answers the research question of how far these process parameters can be effective when the mass of chips to be recycled increases. In specific, an experimental setup was analyzed that was previously identified as challenging for recycling 20 g chips of aluminum alloy AA 2024-O. Rotational speed was set doubled, and processing time was increased up to 1.5 times of their initial values. T…
Experiments and predictions of the transition of the flow pattern with impeller clearance in stirred tanks
2001
In the present work, the double- to single-loop flow pattern transition in a stirred vessel equipped with a Rushton turbine is investigated by Laser Doppler anemometry (LDA). In particular, the clearance at which such transition occurs is assessed by comparing axial velocity profiles underneath the impeller. Computational fluid dynamics (CFD) simulations of the same system are carried out, by employing the 'inner-outer' fully predictive computation strategy. The comparison of predicted results with the experimental data collected shows that the transition is well reproduced by simulations. A good agreement on the mean velocities is also observed but for the impeller discharge stream angle t…
Solid–Liquid Suspensions in Top-Covered Unbaffled Vessels: Influence of Particle Size, Liquid Viscosity, Impeller Size, and Clearance
2014
Particle suspension in liquids is a unit operation commonly encountered in the process industry. Although it is usually carried out in baffled stirred tanks, there are some specific applications where the presence of baffles may be undesirable. In the present work solid-liquid suspensions are investigated in a radially stirred unbaffled tank provided with a top cover. The minimum impeller speed at which all solid particles get suspended (Njs) and the relevant power requirements (Pjs) are assessed. The dependence of these two parameters on physical properties (liquid viscosity, particle concentration, and size) and system geometrical configurations (impeller diameter and clearance) is invest…
Käsityksiä terveysviestinnän luotettavuudesta ja ristiriitaisuudesta internetissä
2016
Tässä pro gradu -tutkielmassa tutkittiin X- ja Y-mediasukupolvien käsityksiä terveysviestinnän luotettavuudesta ja ristiriitaisuudesta internetissä. Tutkimuksen tutkimuskysymykset olivat: 1. Mistä asioista kokemus terveysviestinnän luotettavuudesta syntyy? Sekä 2. Miten ristiriitaiseen terveysviestintään suhtaudutaan? Tutkimuskysymyksiä tutkittiin vertailevasti X- ja Y-mediasukupolvien välillä. Lisäksi tarkoituksena oli selvittää, eroavatko terveysviestintään kohdistuvat käsitykset kahden mediasukupolven välillä. Tutkimus toteutettiin sähköisenä kyselytutkimuksena, missä vastaajajoukko koostui 109 henkilöstä (N=109). Vuonna 1964 - 1979 syntyneitä (X-mediasukupolvi) oli aineistossa 43 prosen…
Effect of broadband noise on adiabatic passage in superconducting nanocircuits
2010
With the rapid technological progress in quantum-state engineering in superconducting devices there is an increasing demand for techniques of quantum control. Stimulated Raman adiabatic passage (STIRAP) is a powerful method in quantum optics which has remained largely unknown to solid-state physicists. It is used to achieve highly efficient and controlled population transfer in (discrete) multilevel quantum systems[1]. Apart from other potential applications in solid-state physics, adiabatic passage offers interesting possibilities to manipulate qubit circuits, in particular for the generation of nonclassical states in nanomechanical or electromagnetic resonators[2]. In this contribution, w…
The pure descent statistic on permutations
2017
International audience; We introduce a new statistic based on permutation descents which has a distribution given by the Stirling numbers of the first kind, i.e., with the same distribution as for the number of cycles in permutations. We study this statistic on the sets of permutations avoiding one pattern of length three by giving bivariate generating functions. As a consequence, new classes of permutations enumerated by the Motzkin numbers are obtained. Finally, we deduce results about the popularity of the pure descents in all these restricted sets. (C) 2017 Elsevier B.V. All rights reserved.
A comparative high-pressure jet-stirred reactor study on the oxidation of pentanol isomers: 1-, 2- and 3- pentanol
2018
International audience
An experimental and modelling study of the oxidation of 3-pentanol at high pressure
2018
International audience; High pressure oxidation of 3-pentanol is investigated in a jet-stirred reactor and in a shock tube. Experiments in the reactor were carried out at 10 atm, between 730 and 1180 K, for equivalence ratios of 0.35, 0.5, 1, 2, 4 and 1000 ppm fuel, at a constant residence time of 0.7 s. Reactant, product and intermediate species mole fractions were recorded using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). Ignition delay times were measured for 3-pentanol/O2 mixtures in argon in a shock tube at 20 and 40 bar, in a temperature range of 1000–1470 K and for equivalence ratios of 0.5, 1 and 2. The fuel did not show any low-temperature reactivity…
Characterization of the aromatic potential of grape berry
2022
IntroductionProbe is a research infrastructure gathering 4 analytical platforms of INRAE and allowing multi-approach and multi-complementarity to be explored and exploited. As a proof of concept, a common study was conducted around the structure and the evolution of the skin of the grape berry and the diffusion of compounds of interest during the winemaking process.Materials and methodsIn this context, the aromatic potential on two Vitis vinifera grape varieties (Carignan and Grenache,) were studied. Berries were harvested at an average potential alcohol of 12% vol. in the vineyard of the Pech Rouge experimental unit (INRAE, Gruissan, France) and separated according to their natural heterog…