1,720,962 research outputs found
Elaboración y caracterización de aleaciones ferrosas con memoria de forma para uso industrial: un proceso de producción de acoples sin costura
Full text linkEl primer objetivo de esta tesis fue evaluar el efecto memoria de forma (EMF) en dos aleaciones inoxidables Fe-Mn-Si-Cr-Ni, analizando cómo afecta la composición química y el procesamiento termomecánico. Colamos dos aleaciones de composiciones Fe-16,9Mn-6,2Si-9,3Cr-5,0Ni (17Mn), y Fe21,2Mn-3,7Si-9,4Cr-4,4Ni (21Mn), y las procesamos por laminado a 650, 800 y 1000 °C; luego aplicamos recocidos de 30 minutos a diferentes temperaturas entre 500 y 1000 °C para modificar la estructura de defectos. Encontramos que el mejor comportamiento de MF en ambas aleaciones se logra con un recocido a 700 °C en las chapas laminadas a 1000 °C. La aleación 17Mn muestra un EMF claramente superior a la 21Mn, con GRF de 88 y 78% medidos en ensayo de flexión y tracción respectivamente, y una tensión de retransformación de 490 MPa.
El segundo objetivo fue diseñar un método que combina características del punzonado
y la extrusión directa, para el conformado de tubos sin costura de aleación 17Mn.Fil: Esquivel, Isidro G. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura. Rosario; Argentina
Design, manufacturing and performance OF Fe–Mn–Si–Ni–Cr shape memory seamless couplings
Full text linkThe Fe–Mn–Si shape memory (SM) alloys have attracted a great deal of interest due to their good technological characteristics and mechanical properties, combined with the SM effect. They are especially useful for applications like shaft and pipe couplings. In this work, we present the development and evaluation of a procedure to manufacture SM seamless couplings. After analysing industrial forming methods, we designed and fabricated a prototype of a punch-extrusion (PE) die and obtained seamless tubes of satisfactory quality and length for manufacturing couplings. Finally, we measured the performance and SM properties of the PE couplings and compared these characteristics to those of couplings machined from a cast ingot. We concluded that a multi-step processing is an efficient solution that mitigated problems resulting from billet cooling during punching because it allows the alloy to be reheated. The PE couplings that were diametrically expanded 4% and annealed at 700 °C exhibited 75% shape recovery, while the control samples showed 20% less recovery. The union of 21 mm diameter shafts by means of PE couplings annealed at 700 °C showed 40 N-m/cm2 normalized torque transmission, which was 25% greater than that found for the cast ingot couplings. We also analyzed the advantages of the PE couplings compared to a traditional shrink-fit connection.Fil: Esquivel, Isidro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Malarria, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Druker, Ana Velia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentin
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
A manufacturing process for shaft and pipe couplings of Fe-Mn-Si-Ni-Cr shape memory alloys
Full text linkIt has been shown that rolling an Fe–15Mn–5Si–9Cr–5Ni (wt.%) alloy at 800 °C followed by annealing at 650 °C gives a structure – a high density of stacking faults and enough austenite hardness – that promotes the stress induced martensitic transformation instead of plastic deformation. After this thermo-mechanical processing, the material recovers around 95% of a 3% permanent deformation excursion. This work addresses the formability and weldability of sheets processed in that manner and how welding affects the mechanical and shape memory properties. Here, the designs and verification are presented for a new method for manufacturing couplings by forming and welding, and finally, the degree of shape recovery in couplings manufactured by this new method are evaluated. The results show that these couplings recover 83% of their diametrical expansion, which make them suitable for many industrial applications.Fil: Druker, Ana Velia. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingenieria y Agrimensura. Escuela de Ingenieria Mecanica; ArgentinaFil: Perotti, A.. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingenieria y Agrimensura. Escuela de Ingenieria Mecanica; ArgentinaFil: Esquivel, Isidro Gabriel. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingenieria y Agrimensura. Escuela de Ingenieria Mecanica; ArgentinaFil: Malarria, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentin
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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