1,721,149 research outputs found
Mixing Due to Natural Convection in a Hydrothermal Reactor: A CFD Study
No full textThe successful design of biomass hydrothermal reactors could be substantially enhanced by computational fluid dynamics (CFD) simulations. However, their performance is still limited by the complexity of the involved physicochemical phenomena and the scarcity of experimental data. This study employs such simulations to analyze the thermo-fluid dynamics of an unstirred batch hydrothermal reactor. By assessing the reactor’s response to a lateral heat source, we show that correctly including various phenomena, such as phase transfers and temperature-dependent properties, enables accurate reproduction of natural convection, providing a more solid base for CFD studies on hydrothermal units. The results provide valuable insights into the reactor’s inner mixing, which for pure water appears adequate despite the absence of stirring. Additionally, we explore two approaches to include a biomass fixed bed or a non-Newtonian sludge. Discussing future efforts needed to make the simulation of such media more established, we show that their presence may indeed hinder mixing, with implications for the products’ quality and safety and for hydrothermal processing control and design
The growing problem of waste bioplastics disposal, and a way to tackle it
No full textBiodegradable plastics will grow significantly in the coming years thanks to their potential for renewability and circularity, particularly in certain European countries. Despite being a niche, their disposal is already emerging as a challenge. Insufficient public awareness is a partial cause, with people being unaware or confused on how to deal with them. Other problems are inherent to the way organic waste treatment plants work. There is indeed a stark contrast between standard biodegradability tests and actual conditions at treatment facilities, often dismissed or ascribed to the negligence of plant operators. If bioplastics are really to be deployed on a large scale, a joint technological effort is essential to properly manage their end-of-life. This contribution briefly summarises the scenario of bioplastic use in the world, the European legislation on the matter (or lack thereof), and the difficulties that waste management plants face with these materials, with a focus on a reference case - Italy - and with an international perspective. Finally, we explore how hydrothermal treatments are emerging in the scientific literature as a possible solution to some of these problems, as they can solubilise most bioplastics and facilitate their treatment in the most updated organic waste treatment plants, which couple anaerobic digestion and composting
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
Dynamic surface tension measurements on molten metal-oxygen systems: model validation on molten tin
No full textpost filter thromboembolic prophylaxis in vena cava filter carriers
No full textpost filter thromboembolic prophylaxis in vena cava filter carrier
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
Ruptured cerebral aneurysms operated on with only MRA. Reports of two cases.
No full textTwo cases of ruptured aneurysms of anterior communicating artery were reported. The aneuryms were showed only by means of MR angiography and operated on without conventional angiography, since patients' allergy to drugs and medium contrast. The MRA showed precisely the sites of the aneurysm and the directions of the sac, but underestimated the size of the sac. In spite of the lack of angiograms induced a great caution during the dissection of the aneurysm and made necessary a larger operative field, anyway clipping of the aneurysm's neck was performed without great difficulties
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
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