Search results for "STIR"
showing 10 items of 426 documents
The waterfront project for the historic centres: the case of the redevelopment of the historic port of Cala di Palermo
2012
The Paper aims to contribute to reflection on the peculiarities of the cases of functional and morphological regeneration of the waterfront historic European cities. Since the identification of a range of issues common to these types of projects, some interventions are analyzed and characterized by approaches different outcomes. We analyze in detail the case of redevelopment of the waterfront's historic city of Palermo, whose degradation is similar to that of many other big cities of the Mediterranean and whose dynamics retraining, are believed to be a useful contribution for debate on the issue of redevelopment of the waterfront of the historic centers. Today the city of Palermo is "denied…
MODELLING, OPTIMIZATION, AND 3E-ANALYSIS OF DISH-STIRLING CONCENTRATING SOLAR POWER SYSTEMS
2022
raggiungimento degli obiettivi del precedente Accordo di Parigi, tutti i Paesi sono stati invitati a impegnarsi a garantire l'azzeramento globale entro la metà del secolo e a mantenere l'aumento della temperatura media globale significativamente al di sotto dei 2 °C, rispetto ai livelli preindustriali, entro il 2050, e più precisamente entro il limite superiore di 1,5 °C. Tutti i Paesi stanno concentrando le loro politiche su una transizione energetica globale che consiste nell'aumento dell'uso di fonti rinnovabili per la generazione di elettricità e nell'uso diretto di calore e biomassa rinnovabili, nell'uso diretto di elettricità pulita nei trasporti e nelle applicazioni termiche, nel mig…
In-process tool force and rotation variation to control sheet thickness change in friction stir welding of magnesium alloys
2016
Two different in-process control strategies, developed in order to produce sound joints in AZ31 magnesium alloy by Friction Stir Welding on sheet blanks with a non-uniform thickness, are presented and compared. To this purpose, sheets with dip or hump were machined and welded by either changing the rotational speed or the tool plunging in order to keep constant the vertical force occurring during welding. The mechanical strength of the joints was measured in the zones where the sheets before welding were characterised by different thicknesses. The sheets welded by the two different strategies are characterized by very similar ultimate tensile strength values. Finally, the results showed tha…
On the friction stir welding of titanium alloys: Experimental measurements and FEM model fine tuning
2012
Friction Stir Welding (FSW) is a solid state welding process patented in 1991 by TWI; initially adopted to weld aluminum alloys, is now being successfully used also for magnesium alloys, copper and steels. Recently, research is focusing on titanium alloys thanks to the high interest that such materials are getting from the industry as welding of titanium alloys by traditional fusion welding techniques presents several difficulties due to high material reactivity resulting in bonding with oxygen, hydrogen, and nitrogen with consequent embrittlement of the joint. In this way FSW represents a cost effective and high quality solution. The study of the temperatures reached at the varying of the …
Particle Suspension in Vortexing Unbaffled Stirred Tanks
2016
Three-phase processes in which particle suspension has to be achieved in conjunction with gas dispersion are traditionally carried out in sparged, baffled stirred tanks. The operation of such tanks can suffer, however, from particles tending to block the sparger holes. A viable alternative might be provided by uncovered unbaffled stirred tanks (UUSTs), where gas self-injection can occur when the free-surface vortex reaches the impeller blades and gas bubbles begin to be ingested by the liquid. In this work, the particle suspension and liquid aeration performances in three-phase UUSTs were experimentally investigated and compared with relevant literature correlations concerning baffled syste…
CFD prediction of solid particle distribution in baffled stirred vessels under partial to complete suspension conditions
2013
Solid-liquid mixing within tanks agitated by stirrers can be easily encountered in many industrial processes. It is common to find an industrial tank operating at an impeller speed N lower than the minimum agitation speed for the suspension of solid particles: under such conditions the distribution of solid-particles is very far from being homogeneous and very significant concentration gradients exist. The present work evaluates the capability of a Computational Fluid Dynamics (CFD) model to reliably predict the particle distribution throughout the tank under either partial or complete suspension conditions. A flat bottomed baffled tank stirred by a Rushton turbine was investigated. Both tr…
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.
Life Cycle Assessment of aluminum alloys chips recycling through single and multi-step Friction Stir Consolidation processes
2023
Manufacturing scientists have to find new processes enabling energy and resource efficient circular economy strategies. Solid state recycling processes have proved to be environmentally friendly alternatives to recycle aluminum alloys process scraps like chips. In this paper the environmental characterization of a solid state recycling process named Friction Stir Consolidation (FSC) is presented. A full Life Cycle Assessment (LCA) comparative analysis is developed: the environmental performance of new and different variants of FSC processes and remelting based routes are quantified and compared to one another. Also, different scenarios are analysed to provide guidelines for the correct impl…
Tekijänoikeuslaki eduskunnan käsittelyssä : digitaalisten oikeuksien hallinnan teknologiat päätöksenteon kohteena
2007
Tässä tutkielmassa tarkastellaan digitaalisten oikeuksien hallinnan teknologioita eduskunnan päätöksenteon kohteena. Tutkimusongelmina selvitän ensiksi kuluttajan ja tuottajan intressejä digitaalisten oikeuksien hallinnan teknologioilla (engl. digital rights management, DRM) suojattuun aineistoon. Toisena tutkimusongelmana selvitän miten ja mitkä kuluttajien ja tuottajien intressit politisoituvat kansanedustajien argumentaatiossa, sekä kolmanneksi tarkastelen miten kansanedustajat politikoivat, toimivat poliittisesti säätäessään tekijänoikeuslain. Ensimmäisen tutkimuskysymyksen aineistona ovat tieteelliset artikkelit, toisen ja kolmannen tutkimuskysymyksen aineistona ovat tekijänoikeuslakik…