1,721,066 research outputs found
Laboratory-Scale Procedure for Evaluating the Flux Efficiency on Melt Cleanliness and Tensile Properties of Recycled Aluminum Alloys
No full textThe present study aims to develop a laboratory-scale procedure to evaluate the efficiency of melt-cleaning and drossing fluxes during aluminum alloy recycling, focusing on their effects on melt cleanliness and tensile properties of an AlSi9Cu3(Fe) alloy. X-ray fluorescence and diffraction, as well as differential scanning calorimetry, are used to characterize two different commercial fluxes. The molten metal is treated at 720 and 760 degrees C. Reference melts without flux treatment are also collected. The melt sampling procedure involves H2 concentration monitoring, reduced pressure test (RPT), and casting of tensile specimens. The composition of the generated dross is analyzed too. Differences are encountered in the chemical composition of the analyzed fluxes, while they exhibit similar melting temperatures. The RPT emphasizes the advantages of flux treatment on melt cleanliness. The tensile plastic properties, including ultimate tensile strength and ductility, are influenced by the flux treatment, while the elastic properties, such as yield strength, remain unaffected. The Weibull analysis allows us to discriminate the efficiency between the different processing conditions. Additionally, the three-parameter Weibull statistics highlights the significance of flux treatment and temperature monitoring to increase the threshold value. The dross analysis highlights the importance of flux treatment to minimize metal losses
Explicit and implicit attitudes toward gay and lesbian scenarios and traditional gender roles: sexual orientation, sexual stigma and perceived masculinity/femininity
Full text linkThe main purpose of the current doctoral dissertation was to contribute to the literature about negative attitudes toward gay and lesbian individuals, within the sexual minorities themselves.Considering how strong the traditional gender roles is related to sexual stigma and internalized sexual stigma in heterosexual and sexual minorities respectively, we wanted to deepen their interaction role on peoples’ negative attitudes toward gay and lesbian individuals, who are not conform to stereotypical gender roles.The first study of this dissertation will investigate the role of participants’ sexual orientation and perceived masculinity on negative attitudes toward two gay man scenarios. Specifically, we will compare explicit negative affect toward stereotypical feminine and masculine gay man scenarios in an Italian sample of heterosexual and gay men. This research will extend previous literature, exploring gay men’s attitudes to feminine and masculine gay scenarios, also focusing on the impact of their internalized sexual stigma.
The main purpose of the second study of this doctoral thesis will be to extend the investigation on negative attitudes both in lesbian participants and toward stereotypical masculine and feminine lesbian scenarios. This research will examine the differences between Italian gay men and lesbian participants in their negative attitudes toward either gay or lesbian scenarios, described with either stereotypical masculine or feminine characteristics.
The third study will focus exclusively on Italian lesbian participants. This is the first study to explore negative attitude toward gay and lesbian scenarios, by investigating lesbian participants’ internalized sexual stigma and their adherence or violation of traditional feminine role. The scenarios will be the same of the second study and represent either a gay man or a lesbian woman conforming to either masculine or feminine traditional gender roles.
The last study of this doctoral dissertation will describe the effects of heterosexual and gay men’s manipulation of masculinity threat, their sexual stigma and their adherence to traditional masculinity on the implicit attitudes toward feminine and masculine gay men. First of all, the description of the several construction phases of this instrument and the two pilot studies will be illustrated. Afterwards, the description of the main study will follow
Effect of NaCl, KCl e Na3AlF6 on the refining process of aluminium alloys
No full textTo maximize the efficiency of the fluxes during the refining of the aluminium alloy scrap, a proper balance of the salts is required. This study preliminarily investigates the influence of different concentrations of NaCl, KCl and Na3AlF6 on the chemical and physical properties of the fluxes used during the refining process of the aluminium alloys. The melting temperature and the viscosity of the flux at different concentrations of NaCl, KCl and Na3AlF6 were analysed, as well as the ability to dissolve the aluminium oxide. Furthermore, the dissolution of the flux in water was investigated. The results showed how the melting temperature of the flux decreases, while the viscosity increases as the cryolite content increases. The attitude of dissolving the Al oxide is favoured by the addition of Na3AlF6, even at low concentrations and reduced time of treatment. The dissolution of the oxide allows the liquid aluminium entrapped in the scrap to be released and to return into the molten bath, thus increasing the yield of the refining process. On the contrary, the dissolution of the flux in water is reduced after the addition of cryolite
Scatter Bands Summarising the Fatigue Strength of Aluminium Alloy Bolted Joints
No full textA large number of geometrical, technological and environmental factors theoretically influence the fatigue behaviour and the failure modes of the bolted joints. In order to make clear the influence of some of such variables, in this work over one hundred aluminium symmetric double butt joints were tested, subdivided into eight series, with the purpose to compare their fatigue properties and display failure mechanisms. All tests have been carried out under load control, taking into account plates in 7020-T6 and 6061-T6 light alloys connected by means of A2-70 stainless bolts or 8.8 high strength bolts, in such a way that failure modes were different.
The new results, together with those already presented by one of the authors in a recent contribution (Atzori et al. 'Proceedings of the Sixth International Conference on Aluminium Weldments', Cleveland, OH, 1995, pp. 243-254), in which 2024-T4 aluminium alloy and 10.9 high strength bolts had also been considered, allow both a comparison among the series and their synthesis in a very reduced number of scatter bands which seem to depend, for the three alloys taken into account, mainly on the nominal load ratio R, as soon as different definitions of the nominal stress amplitudes are chosen for friction or bearing-type joints
Solid Salt Fluxes for Molten Aluminum Processing—A Review
Full text linkAluminum recycling is a promising solution to environmental and economic issues. Secondary aluminum production will rise in the near future; however, the process is not without challenges. Some of the major concerns during remelting of aluminum are the metal losses due to the oxidation of the molten metal and the removal of impurities from the metal bath. The current study summarizes the latest progress in the use of solid salt fluxes for secondary aluminum production and the treatment of molten metal. The chemistry of solid fluxes has been reviewed, with a correlation to their main chemical and physical characteristics, such as density, fluidity, wettability, and reactivity. An overview of the main types of solid fluxes is also provided, with a particular focus on their functions and applications. The efficiency of solid fluxes relies on several factors, including but not limited to the fluxes’ chemical composition and physical properties, flux amount, processing temperature, and flux morphology. The effect of salt fluxes in delivering satisfactory metal cleanliness and sufficient metal recovery has been summarized according to the main flux’s properties
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
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
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