1,720,968 research outputs found
MG-Bases alloys as sensing materials for a continuous fiber optic hydrogen sensor
No full textProyecto confidencial (Riunet)Victoria García, M. (2013). MG-Bases alloys as sensing materials for a continuous fiber optic hydrogen sensor. https://riunet.upv.es/handle/10251/33448.Archivo delegad
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
Variations on the Author
Full text link“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
Full text linkWe 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
Electrolytic Plasma Cleaning of Advanced High Strength Steels
No full textThe most commonly used material in the automotive industry is steel. Steel used in making Body-In-White (BIW) for cars are broadly classified as Advanced High Strength Steels (AHSS). These AHSS are produced by a well-defined alloying and specific annealing procedure. However, external oxidation of the constituent alloying elements from the steel is observed the annealing step . This selective oxidation of alloying elements on the steel surface affects the adhesion of the Zinc to the steel which is essential for corrosion protection. The main goals of this research work were to define the optimal parametric windows for the Electrolytic Plasma Cleaning technique to form a plasma capable of cleaning a steel surface by removing external oxides formed during the annealing process. Electrolytic Plasma Cleaning uses the traditional electrochemical cell that consists of an anode, a cathode, an external potential and an electrolyte but at higher input potentials. An experimental setup was developed with the aim of finding the ideal working parameters, establishing the groundwork for future large-scale experimentation.Mechanical Engineering | Vehicle Engineerin
Acid etching as a surface pre-treatment step for PVD coatings on high strength steels
No full textCoating deposition by Physical Vapour Deposition (PVD) on high strength steels is an important research project at TATA Steel - IJmuiden. The research is aimed at replacing the conventional hot-dip galvanisation process to obtain a defect-free coating without affecting their well-engineered properties. However, the annealing treatment of the steel, performed to obtain these properties, affects the coating adhesion properties. This is a result of the selective oxidation process, which forms external oxides of alloying elements at the surface. Therefore, a pre-treatment process is required to remove these surface oxides from the steel strips before they are coated. Plasma sputtering is currently beingused for the pre-treatment to remove any contaminants and surface oxides from the steel. To obtain a good coating adhesion, a relatively large amount of surface oxides needs to be removed by sputtering. Also, the removed material is known to contaminate the vacuum chamber in the PVD deposition line, for which frequent maintenance of the chamber might be necessary. Thus, an additionalsurface pre-treatment step was investigated in this study to reduce the sputtering process inside the vacuum as much as possible. In the present work, the effect of both direct current electrolytic alkaline cleaning and sulphuric acid etching on the surface of DP800 steel was investigated. Two different baths were considered for this purpose; a 27 g/L NaOH bath with some additive at 60°C and a 50 g/L H2SO4 bath at 25°C and 50°C. A current density of 1.5 A/dm2 was applied during the electrolytic cleaning for which both cathodic and anodic polarisation methods were investigated. Also, a range of acid etching times (10s to 120s) was investigated for the given concentration and temperatures of the acid bath to study its effect on the surface. The effect of adding a corrosion inhibitor into the acid bath on the rest of the coating deposition process was also investigated. Various surface characterisation techniques and wettability tests were performed to study the changes in morphology and composition of the surface and their effect on the coating adhesion properties of the treated samples. Finally, coating adhesion tests were performed after zinc deposition to investigate the adhesion performance of the steel after the pre-treatment steps. Initial surface analysis during electrolytic alkaline cleaning showed that the anodic polarisation was more effective than cathodic polarisation of the sample, as the latter tends to reduce the surface wettability by additional deposits of iron fines over the surface. A subsequent acid etching provided a reduction in the minimum required sputter intensity to obtain a good adhesion from 2300 kJ/m2 to about 800 kJ/m2. A further reduction was achieved to a sputter intensity of only 214 kJ/m2 after retarding the effects of surface reoxidation by vacuum sealing the samples. Acid etching at 25°C provided bad coating adhesion at lower etching times, attributed to the partial dissolution of surface oxides and absence of an initial grain roughening. Good coating adhesion was either obtained at higher etching times or by increasing the temperature of the acid bath to 50°C. Addition of a corrosion inhibitor was considered impractical as high sputter intensities (> 321 kJ/m2) was required to remove the adsorbed inhibitor molecules from the surface. Thus, a reduction in the required sputter intensity was achieved by more than a factor of 10 after acid etching, only if the effects of surface reoxidation during the transfer time between acid etching and entering the PVD installation can be minimized.Surface pre-treatment for PVD coatings of HSS | TATA Steel R&DMechanical Engineering | Vehicle EngineeringMaterials Science and Engineerin
Acid etching steel substrate pre-treatment for the physical vapor coating deposition process
No full textIn recent years, Tata Steel Europe has increased their focus on Physical Vapor Deposition (PVD) for the zinc coating application of their steel substrates, as an alternative to Hot Dip Galvanizing (HDG). PVD offers some benefits over HDG like multilayer structures and lower heat impact on the steel. To achieve sufficient coating adhesion strength of the zinc coating, before deposition the steel substrate is normally cleaned and activated by a plasma sputter unit. As this sputtering takes place in the vacuum chamber, like the deposition, it is prone to precipitation of sputtered material in the vacuum chamber. If the PVD process is scaled up to an industrial coating line, the volumes of sputtered material and precipitated material will become problematic for the service reliability. Therefore it has been investigated whether an acid etching surface pre-treatment step before the vacuum chamber could reduce the needed plasma intensity, and thereby decrease the sputtered volume in the vacuum chamber. A range of acid etching times and plasma sputtering times were tested, to obtain the range in which the coating adhesion was sufficient. To test the coating adhesion, two (automotive) tests were used. It was found that by pickling, the plasma sputter intensity could not be reduced. So the coating adhesion strength seemed not directly related to the pickling time, for the particular steel used in this project. After the limits of good adhesion were determined, the characterization started to identify what in the elemental composition or the surface morphology could determine whether there was good adhesion or not. It was found that (even very short) pickling completely removes the surface enrichment of the first 50 nm, while plasma sputtering only lowers the surface enrichments. It was found that plasma sputtering does not influence the morphology, while pickling smoothens the surface out, with increasing pickling. As the oxygen concentration profile did not change significantly as function of pickling time, but its enrichment thickness was about equal to the minimum plasma sputter depth, it is thought that the oxygen concentration is the major influence on good and bad adhesion. Mechanical Engineerin
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
- …
