1,721,049 research outputs found
Effectiveness of numerical simulation in avoiding defects in hot extrusion forging products
No full textApplication of a decision making method to improve an industrial hot extrusion forging process
No full textWavelets image analysis for Friction Stir Processed TiNi functional behavior characterization
No full textA 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 preserve the shape memory properties and retain, furthermore, the cyclic stability of SME. The basic objective of this study was to investigate the feasibility of friction stir welding process to join TiNi shape memory alloy sheets flat memorized, preserving the TiNi shape memory behaviour. This aim has been pursued determining the influence of the thermomechanical modifications induced by Friction Stir Processing of TiNi sheets on the functional properties of material. Optical microscopic investigations of Friction Stir Processed material cross sections have been used to highlight the modified microstructure of processed zone. A proper image processing procedure has been performed in order to quantify the amount of martensitic phase and to detect its morphology modification along the processed region. Particularly each micrographic image at first has been denoised using the 2D Wavelet transform technique and successively a texture segmentation procedure allows evaluating the amount of the martensite and austenite phases and classifying the morphological changes of martensitic regions. The austenitic and martensitic transformation temperatures of material were investigated using a stress applied characterization method suitably set up to perform the whole stress-temperature material characterization
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
