1,720,970 research outputs found
Tensile strength of Nitinol flanges fabricated by laser rod end melting and immediate flange processing
No full textNitinol is a shape memory alloy used for actuator applications. However, the connection between Nitinol wire and mechanical system via adhesive bonding or crimping could be weakened due to the exposure of joint in aggressive environments and temperature changes. Therefore, a process chain called laser rod end melting with immediate flange processing has been put forward and proven to fabricate all-in-one Nitinol flanges. According to previous work, there is a partially solidified preform connecting to the wire as the shaft, where the connection factures under tensile tests. In the present study, the effect of size of partially solidified preform on the tensile behavior was investigated on the cylindrical flanges with different flange heights. The results show that the partial preform volume increases with the flange heights, while the tensile strength becomes smaller when the flange height is too small. This suggests that it is important to maintain the mechanical strength of Nitinol flange by choosing the appropriate flange height.Deutsche Forschungsgemeinschaft DFG, German Research Foundation182
Influence of electrolyte concentration on laser chemical machining
No full textTo meet the increasing trend of miniaturization, new (non-conventional) manufacturing processes are constantly being developed. The laser chemical process describes one of these non-conventional removal process in the microscale, based on the thermochemical dissolution of metals. To determine the influence of electrolyte concentrations, linear cavities were created in Titanium Grade 1 using phosphoric acid and sulfuric acid with different concentrations. The experimental results show that as the electrolyte concentration increases, the process window is reduced. One possibility for this is, as the electrolyte concentration increases, the viscosity increases, as well. With increasing viscosity, the electrolyte boiling process, which causes the shielding effect of the gas bubbles becomes more significant. Due to the increasing conductivity of the electrolyte at higher concentrations, the laser chemical removal rate increases within the process window at constant laser power. The maximum removal rate is observed at the maximum conductivity of the electrolyte.Deutsche Forschungsgemeinschaft DFG323
On the combination of plasma nitrided surfaces and LIPSS
No full textLIPSS are subjected to excessive wear when exposed to direct contact in tribological applications. Therefore, precautions must be taken to increase LIPSS’ hardness and wear resistance while simultaneously preserving their properties like superhydrophilicity. This work shows that a firstly plasma nitrided and subsequently structured surface results in LIPSS of high nano-hardness (14.88 GPa ± 1.05 GPa) who show a super hydrophilic wetting behavior (contact angle of 7°). The results indicate that a previous nitriding could bring LIPSS into tribological applications.Deutsche Forschungsgemeinschaft DFG232
Macro-pore free sub-surface PBF-LB/M components through laser polishing
No full textDespite notable improvements in the laser-based powder bed fusion of metals (PBF-LB/M) in recent years, residual porosity is still an issue. Near surface pores can affect the functional properties of PBF components, such as their fatigue life, yield strength, or corrosion behavior. To help address the challenge, this work shows that laser polishing decreases the surface roughness while also creating a highly dense sub-surface region of PBF parts with only microscale pores remaining.Deutsche Forschungsgemeinschaft DFG, U.S. National Science Foundation374
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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