Search results for " STIR"

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…

Influence of Joint Geometry on Micro and Macro Mechanical Properties of Friction Stir Spot Welded Joints

2014

AbstractSpot welding can be considered a very common joining technique in automotive and transportation industries as it permits to obtain effective lap-joints with short process times and what is more it is easily developed through robots and automated systems. Recently, Friction Stir Spot Welding (FSSW) has been proposed as a natural evolution of the already known Friction Stir Welding (FSW) process, allowing to obtain sound spot joints that do not suffer from the insurgence of typical welding defects due to the melting of the base material. Similarly to FSW, both geometrical and technological parameters must be considered as they affect the material flow and the heat flux generated durin…

Shear models of Rc-encased steel joist beams in MRFs

2019

This study presents the application of different analytical and finite element (FE) models aimed at predicting the shear resistance of reinforced concrete (RC) and reinforced concrete-encased steel joist (HRCESJ) beams with inclined transversal reinforcement in moment resisting frames (MRFs). In particular, four analytical models are taken into account, two of them specifically conceived for HRCESJ beams in seismic area. The analytical models considered are Eurocode-2 model for the shear strength of RC beams; a variable-inclination stress-field approach; a strut-and-tie additive model and, finally, an analytical formulation in which the shear capacity depends on the number of pairs of incli…

Wavelets Image Analysis for Friction Stir Processed TiNi Functional Behavior Characterization

2015

Abstract A key topic regarding Ti Ni Shape Memory materials concerns the possibility to attain welded junctions that preserves the shape memory properties of material. Other research topic for SMAs regards the retention of the shape memory effect cyclic stability; in fact, good shape memory properties frequently decrease during SME cycling of material. A method able to improve the cyclic stability of TiNi shape memory effect is the grain refinement. Considering these above mentioned research topics, a solid state welding process, as the Friction Stir Welding, is thus attractive for SMA joining and it exhibits potentials for achieving welded joints affected by microstructural changes that pr…

CFD simulation of solid-liquid suspension startup in a stirred tank

2008

Top-covered unbaffled stirred tanks: experiments and numerical simulations

2015

In this work computational fluid dynamics was employed to predict the flow field of an unbaffled stirred tank from steady to turbulent conditions

On the Simulation of Solid Particle Distribution in Multiple Impeller Agitated Tanks via Computational Fluid Dynamics

1998

Properties Augmentation of Cast Hypereutectic Al–Si Alloy Through Friction Stir Processing

2022

AbstractThe present endeavour is to augment mechanical attributes via friction stir processing (FSP) in hypereutectic aluminium–silicon castings by the means of microstructural modifications and defects reduction. Wherein, the study proceeds with mainly two approaches namely, alteration in tool revolution (TR) and the number of FSP passes. The prepared specimens were evaluated investigating volume fraction of porosities, microstructural characterizations and microhardness. Therefrom, the specimen with highest number of passes delivered most uniform properties resulting from the reduction in casting porosities and refined silicon particle uniform distribution throughout friction stir process…

Modeling of continuous Ph-stat stirred tank reactor withLactococcus lactisssp.lactisbv.diacetylactisimmobilized in calcium alginate gel beads

1995

A dynamic diffusion-reaction-growth model is proposed for the study of lactic fermentation, the bioconversion of citric acid, and cell release in an immobilized cell reactor [pH-stat continuous stirred tank-reactor (CSTR)]. The model correctly simulates the onset of fermentation and colonization of the gel, followed by the steady state. External diffusion is nonlimiting and internal diffusion is limited by high cell densities at the periphery of the gel beads. Lactose-citrate cometabolism in the gel is related to the distribution of active included biomass within the gel and to gradients of substrates (lactose, citrate) and products (lactate, pH) in the beads. The utilization of lactose is …

Experimental and fluid dynamic study of continuous supercritical water gasification of glucose

2016

Abstract The supercritical water gasification (SCWG) of glucose as a model compound for H 2 production is studied in term of process development at 25 MPa and 650 °C. Gasification has been investigated using a laboratory scale continuous plant comprising a continuous down flow reactor with a volume of 200 cm 3 , a heat recovery section and pre-heat of the biomass to simulate more closely an industrial design. Feed streams (pure water and glucose solution) are introduced at the top of the vessel and products are extracted from the bottom. The reactor is equipped with various inlet points that allow to modify the inlet position of reacting streams in order to study the effect of stream mixing…