Search results for "Tecnologie"
showing 10 items of 1379 documents
On the material flow in fsw of T-joints: influence of geometrical and tecnological parameters
2008
Friction stir welding (FSW) now definitively reached a large interest in the scientific community and what is more in the industrial environment, due to the advantages of such solid state welding process with respect to the classic ones. The latter aspects are relevant also with reference to joints characterized by a complex geometry. What is more, advanced FEM tools permit to develop effective engineering of the processes; quantitative results can be acquired from numerical simulations once basic information, as the process mechanics and the material flow, are certain. Material flow plays a fundamental role in FSW since it determines the effectiveness of the joints or, in turn, the insurge…
Friction stir welding of tailored joints for industrial applications
2009
Friction stir welding (FSW) is an energy efficient and environmentally "friendly" (no fumes, noise, or sparks) welding process, during which the workpieces are welded together in a solid-state joining process at a temperature below the melting point of the workpiece material under a combination of extruding and forging. Since its invention in 1991 by TWI, such process has been reaching a continuously increasing popularity among aerospace, automotive and shipbuilding industries due its capability to weld unweldable or difficult-to-weld light alloys in different joint morphologies. In this paper a wide experimental campaign is carried out in order to obtain T and lap joints characterized by d…
Shape and dimensional accuracy in Single Point Incremental Forming: State of the art and future trends
2007
Abstract The paper is aimed to discuss some relevant issues concerning an innovative sheet metal forming technology, namely Single Point Incremental Forming. The advantages of this technology are addressed, including its capability to provide effective answers to some impellent industrial requirements: process flexibility, strong customer orientation, production of highly differentiated goods at low industrial costs. As well some relevant drawbacks are highlighted, mainly as concerns the level of accuracy permitted by the process. A wide recognition of the research efforts in this field is presented, taking into account some general considerations on the difference sources of shape and dime…
On the FSW of AA2024-T4 and AA7075-T6 T-joints: an industrial case study
2009
In this paper, the authors present the results of a wide experimental campaign on aeronautical T-shaped parts of industrial interest characterized by dissimilar materials for the skin and stringer. The friction stir welding process engineering was developed with the aim to determine the specific process parameters determining the soundness on the obtained T-parts both from the metallurgical and mechanical point of view. Furthermore, the performance of the obtained T-joints was investigated.
Distributed intelligent control of exceptions in reconfigurable manufacturing systems
2003
In order to react to the continuous and unpredictable changes in product demand, in product variety, and in process technologies, reconfigurable manufacturing systems allow quick adjustment of production capacity and functionality by rearranging or changing their modular components. In this kind of system, operation management issues, such as exception handling policies, become more complex since correct reconfiguration strategies have to be selected. This paper explores the potential of the reconfigurability feature to be a basis for the development of new strategies to handle out-of-the-ordinary events in the production process; in particular, maintaining production flow when machine brea…
A comprehensive analysis of electric energy consumption of single point incremental forming processes
2014
Abstract Production processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental impact. The present paper proposes a comprehensive energetic analysis of Single Point Incremental Forming Processes (SPIF). The three most commonly used machine tool architectures able to perform SPIF operations have been taken into account: a CNC milling machine, a six-axes robot as well as the dedicated AMINO machine tool were analyzed from an electrical energy consumption point of view. For all the setups, a working cycle time study and power study were performed. Moreover the cont…
A new approach to study material bonding in extrusion porthole dies
2009
Abstract Porthole die extrusion processes are widely spread even for most recent industrial applications. In turn knowledge base is often linked to make best expertise rather than to scientific fundaments. In the last years several FE models were developed but actual material bonding was not taken into account. In the paper a new approach is presented determining the critical value of the bonding criterion from flat rolling experiments and modelling the actual welding occurring in extrusion of complex profiles. The criterion was tested considering an industrial porthole die extrusion process and experimental parts were analysed to validate the proposed approach.
Freshness Indexes of Anchovies and Sardines of Mediterranean Sea
2012
Anchovy (Engraulis Encrasicholus) and sardine (Sardina Pilchardus) are blue fishes linked to our alimentary tradition of Mediterranean. In our work, particularly, we tested for the first time physical and enzymatic methods to verify the freshness of species of blue fish, anchovy and sardine of Mediterranean. In connection with to the lowering of the pH after post-mortem stage we assisted to a increase in proteolytic activity of calpaine and catpsine. Already after 2 h in post- mortem there was a considerable increase.
Biological effects and photodegradation by TiO(2) of terpenes present in industrial wastewater.
2010
Abstract The aim of this work was to study the biological effects of four monoterpenes, i.e. α-pinene, β-pinene, 3-carene and d -limonene present in the wastewater of a citrus transformation factory. The study was carried out by exposing V79 Chinese hamster cells to single terpene or to the mixture of four terpenes at concentrations corresponding to those in the wastewater evaluated by head space solid phase micro extraction and gas chromatography (HS-SPME-GC) analyses. Treatments with single or combined terpenes similarly affected cell vitality, but only the combined treatments induced the 6-thioguanine resistant mutants. Moreover the photocatalytic degradation of the four terpenes was suc…
A survey of photocatalytic materials for environmental remediation
2012
Abstract Heterogeneous photocatalysis is an advanced oxidation process which has been the subject of a huge amount of studies related to air cleaning and water purification. All these processes have been carried out mainly by using TiO 2 -based materials as the photocatalysts and ca. 75% of the articles published in the last 3 years is related to them. This review illustrates the efforts in the search of alternative photocatalysts that are not based on TiO 2 , with some exceptions concerning particularly innovative modifications as nanoassembled TiO 2 or TiO 2 composites with active carbon, graphite and fullerene. Papers reporting preparation, characterization and testing of binary, ternary…