1,721,147 research outputs found
Thermal stress analysis of PCM containers for temperature smoothing of waste gas
No full textThis article develops an analytical and numerical approach to evaluate thermal stress in a phase change material (PCM) system, used for temperature smoothing of waste gas of Electric Arc Furnace, in which the PCM is encapsulated in a cylindrical steel container. Thermal analysis shows that temperature distribution in the PCM system can be considered as uniform at any time instant according to the lumped capacitance method; the thermal behaviour of PCM system is thus simulated as a sequence of steady state analyses. Mechanical analysis adopts an axialsymmetric plane analytical model to compare elastic thermal stress distribution for different stainless steels and to identify AISI 316 as the most suitable material for the PCM container. A simple two-bars model and a stress index are also used to allow a physical understanding and a satisfactory interpretation of the PCM system response. Mechanical analysis shows that thermal stresses exceed the yield point of both stainless steels used in the container. A finite element elastic-plastic model is then developed to estimate the extension of the plastic zone. Finally, an alternative PCM system geometry based on concentric pipes is designed to keep the maximum stresses in the PCM container below the yielding point. A sensitivity analysis shows that the most relevant design parameters of the alternative geometry are the diameter of inner pipe and thickness of the external pipe
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
Endoscopic treatment of quadrigeminal cister arachnoid cysts.
No full textFive patients with arachnoid cysts of the quadrigeminal cistern
treated by endoscopic fenestration are reported and another eleven well−documented cases from the literature are reviewed.
Among the five personal cases four were children and one was adult; the cyst fenestration was performed from the lateral ventricle in three cases and from the third ventricle in two. In four patients the endoscopic treatment resulted in clinical remission, whereas a two−month−old baby later required a shunt. The lateral ventricle−cystostomy and the third ventricle−cystostomy (according to the cyst extent) are the best endoscopic procedures, whereas the cyst fenestration through a suboccipital supracerebellar approach is no longer used. The rate of cured or improved patients after endoscopic surgery (14/16 or 87.5%) was rather similar to that of a group of twenty patients treated by traditional
surgery (craniotomy and cyst excision and/or shunt) (85%).
These data confirm that endoscopic fenestration of quadrigeminal cistern cysts must be performed as the first procedure because it is less invasive and avoids shunt dependency
Combined endoscopic and microsurgical removal of a giant cystic craniopharyngioma in a six-year-old boy
No full textGiant cystic craniopharyngiomas are rare lesions whose clinical and surgical management is extremely challenging, often requiring more than one craniotomy before obtaining a satisfying removal.We report one case of a giant cystic craniopharyngioma completely excised with a two-step combined use of a minimally invasive endoscopic approach followed by a single microsurgical transcranial procedure.
A six-year-old boy presented with symptoms of increased intracranial pressure and posterior fossa involvement. Preliminary imaging revealed a large para- and suprasellar cystic tumor bulging superiorly into the third ventricle, and extending posteriorly from the retroclival region into the posterior fossa to the level of the foramen magnum.
The suprasellar cystic quota was initially approached endoscopically through a right precoronaltransventricular
approach and the cyst drained, while the remaining tumor was macroscopically totally removed one week later by a right pterional approach.
A combined technique – endoscopic drainage followed by microsurgical removal – can be a valid alternative for the removal of giant cystic craniopharyngiomas in cases in which the cystic compartment bulges within the ventricular spaces, and may avoid multiple craniotomies
Consulente del Comune di Venezia per la redazione del Piano di Assetto del Territorio: Sistema dell'accessibilità
No full textDispelling 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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