1,720,991 research outputs found
In-situ TiB2 and Fe2Ti intermetallic assisted hard coatings by Fe-Ti-B based hardfacing electrodes
No full textThe aim of this study was to form Fe2Ti and TiB2 phases on the steel surface in-situ using ferroalloy starting materials and to investigate the changes in the surface properties such as microstructural, hardness, wear and corrosion behavior. To this end, Fe(18-X)TiXB2 (x = 3-5) based hardfacing electrodes were produced and coated on AISI 1010 steel substrate using electric arc welding method. The development of the substrate coating interface, solidification behavior and microstructural conditions of the samples were examined using a variety of characterization methods. In the coating microstructures, intermetallic phases such as TiB2 and Fe2Ti, alpha-Fe + Fe2Ti eutectic structure and trace amounts of non-equilibrium phases were detected. It has been understood that these phases formed in the microstructure have important effects on the hardness, wear and corrosion resistance of the coating. In the hardness test performed by nanoindentation method, very high hardnesses such as 3254 (+/- 26) HV in TiB2 phase and 1130.1 (+/- 13) HV in Fe2Ti phase were measured. As a result of the ball on disc reciprocal wear test performed against Al2O3 ball at different loads, it has been observed that titanium has an effect on the friction coefficient, and the wear resistance increases with the increasing amount of titanium in the electrode cover composition. In addition, according to the potentiodynamic polarization test results carried out in 3.5% NaCl solution, it has been determined that the corrosion potential increased with increasing titanium in the electrode cover composition, there was no linear change detected in the current density. (C) 2021 Elsevier B.V. All rights reserved.Authors are grateful to the financial support provided by TUBITAK (Turkey Scientific and Technological Research) with Project no. 219M192.TUBITAK (Turkey Scientific and Technological Research) [219M192
Metrik olmayan dijital kameraların iç yöneltme elemanlarının belirlenmesi üzerine bir çalışma
No full textBilgisayar teknolojisindeki gelişmelere paralel olarak fotogrametrinin de uygulama alanları artmıştır. Klasik kameraların kullanımının zor oluşu, film gibi materyallerin bulunamayışı ve banyo.gibi kartografik işlerin zahmetli oluşu, fotogrametristleri yeni arayışlara yönelmiştir. Bu çalışmanın amacı da, bu görüşler doğrultusunda amatör, metrik olmayan digital kameraların fotogrametride kullanılıp kullanılamayacağına ilişkin bir sonuca ulaşmaktır. Bu amaçla, üniversitemiz bilgisayar merkezinde bulunan Polaroid PDC- 2000/40 digital kamerasının iç yöneltme elemanlarının bu amaçla bir araştırılması yapılmıştır. Bunun için bir test alanı oluşturulmuş, çekilen resimler fotogrametri laboratuvarında PICTRAN yazılımında değerlendirilmiş ve sonuçları irdelenmiştir. Elde edilen sonuçlara göre bu kamera, yakın resim fotogrametri çalışmalarında kullanılabilir.Parallel to the improvement in the computer technology, the application areas of photogrammetry are also increased. Because of the difficulties both using and finding materials like films of conventional cameras, photogrammetrists tried to figured -out new Aim of the study, is figure out usage of non-metric digital cameras for photogram metric purposes. For this reason, imnterior orientation parameters of Polaroid PDC-2000/40 digital cameras, which is found in the Computer Central of the university were examined. A test field was formed and obtonied photographs of test field were evaluated by means of digital photogrammetric software named PICTRAN, and the results were examined. According to obtonied results; this camera con be use close range photogrammetric application
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
Corrosion Behaviour of Al/(TiB2 + -Al3Ti)-Based Functional Grade Metal Matrix Composite by Sedimentation Method
No full textThe current study examined the producibility and corrosion behaviour of functionally graded Alm/Al3Ti and TiB2 composites by sedimentation method. For this aim, the Al-Ti-B master alloy melted at 800 ℃ in the crucible and kept for 90 min to ensure the sedimentation of Al3Ti and TiB2 particles. In the samples taken from different sections of the crucible via a top-down approach, it was observed that the sedimentation method is rather suitable for obtaining of FGM composite. In the Rietveld analyses conducted across the sections for the refinement of crystal structures, it was determined that the amount of particles increased from top to bottom. Corrosion tests performed in different NaCl concentrations showed that the particle fraction did not have a direct effect on the corrosion resistance of the layers. Also, the highest corrosion resistance was obtained in the D layer without particle reinforcement, corrosion resistance decreased with particle reinforcement. Graphical Abstract: (Figure presented.)
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
Ultra-fine beta SiC nanowires Isothermally converted from high activated silica by Carbothermic Reduction and Carburization at low temperature
No full textThis work was focused primarily on the investigation of the parameters effecting the formation of beta-SiC and their crystallite diameter. Previous works revealed that the preparation of silica used as a precursor was the key factor on the resulting particle features. Therefore, the work aimed to achieve obtaining ultrafine silica precursor with superfine crystallites at relatively low temperatures. In the result, a clear difference was observed between the finally obtained SiC powders in terms of conversion and particle morphology according to the preparation process. The use of a modified high energy ball milling system resulted in a considerable reduction in the size of the starting particle's diameter (>100 nm). The FTIR transmission spectra of the yielded nanowires confirmed the SiC composition with the peak near 950 cm-1, which represents the LO stretching Si-C bond. The precursor preparation process improved the efficiency of Carbothermic Reduction and Carburization process used in the synthesis of SiC nanowires. The XRD findings indicated that all the precursors consisted of only amorphous silica, and the modified high energy ball milling system thermodynamically supported the crystal to amorphous conversion. The SEM micrographs revealed that the SiC nanowires had diameters of 50-100 nm with hundreds of microns in length. The SiC nanowire composed of ultrafine crystalline cubic SiC in beta form. As a result, the silica conversion to silicon carbide was successfully completed at a faster reduction rate and relative lower temperature (1475 degrees C for 4 h)
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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