1,720,974 research outputs found
Combined Production of Hydrogen and Power from Heavy Oil Gasification: Pinch Analysis, Thermodynamic and Economic Evaluations
No full textIntegrated Gasification Combined Cycle (IGCC) represents a commercially proven technology available for the combined production of hydrogen and electricity power from coal and heavy residue oils. When associated with CO2 capture and sequestration facilities, the IGCC plant gives an answer to the search for a clean and environmentally compatible use of high sulphur and heavy metal contents fuels, the possibility of installing large size plants for competitive electric power and hydrogen production, and a low cost of CO2 avoidance.
The paper describes two new and realistic configurations of IGCC plant fed by refinery heavy residues and including a CO2 capture section, which are proposed on the basis of the experience gained in the construction of similar plants. They are based on oxygen blown entrained bed gasification and sized to produce a large amount of hydrogen and to feed one or two gas turbines of the combined cycle unit. The main thermodynamic and technological characteristics of the total plants are evaluated focusing on the heat integration between syngas cooling and combined cycle sections.
Moreover, the overall performance characteristics and investment cost are estimated to supply a reliable estimate for the cost of electricity, given a value for the hydrogen selling price
Peculiar karstic features in the Upper Triassic sulphate evaporites from the Secchia Valley (Northern Apennines, Italy).
No full textIn the Secchia Valley spectacular sulphate outcrops (Burano Fm., Upper Triassic) are composed mostly of gypsum, anhydrite is a minor constituent.The apparent relative dissolution rates of gypsum and anhydrite rocks are variable and result in peculiar karstic features, which have not been reported in other evaporite deposits. Such differential solution phenomenon can be observed both on the fine scale, along outcrop surfaces, and also at the large scale, controlling drainage patterns of rock masses. These peculiar solution features are the gypsum and anhydrite protrusions and the hypogean bends (“anse ipogee”).Gypsum and anhydrite protrusions. Although anhydrite is less soluble than gypsum, anhydrite-bearing rocks show variable behaviours and may be affected by dissolution to a greater extent than the gypsum rocks. Fine-grained anhydrite layers and lenses, enclosed in gypsum rocks, protrude from the surrounding gypsum, whereas the coarse-grained anhydrite rocks are more depressed. This effect is due to the presence of gypsified rims on the coarse-grained anhydrite crystals. When running water flushes the rocks, gypsum in the rims dissolves faster than anhydrite. The partially gypsified coarse-grained anhydrite is more deeply attacked because the anhydrite crystals fall away from the rock surface or are carried away by the water as gypsum rims are removed. In layers where gypsification of the anhydrite crystals is negligible, and this is the case for the fine-grained variety, the anhydrite rocks are less attacked and form protrusions relative to the gypsum layers.Hypogean bends (“anse ipogee”). The karstic systems run only at a short distance from the surface, where gypsum is dominant. The expected presence of a larger amount of less soluble anhydrite in the core of the outcrops seems to prevent the development of karstic systems cutting across the sulphate masses. The karstic drainage is concentrated along joints parallel to the valley incisions, following release fractures developed as a consequence of the dramatic drop in internal rock pressure due to rapid valley-floor deepening. Because the Secchia Valley is characterized by small streams, almost orthogonally-oriented with respect to the main valley, the karstic systems may seem to flow uphill where they intercept the joints running parallel to the Secchia valley. This peculiar effect is related to the presence of alluvial and mud-slide deposits, which act as barriers and do not allow the direct down slope resurgence of the karstic waters
The mechanics of anoikis resistance in cancer
No full textMetastatic cancer cells display a remarkable ability to resist the mechanical and biochemical challenges associated with detaching from the extracellular matrix and metastasize. A key adaptive mechanism in this process is resistance to anoikis. In this review, we explore the molecular and biophysical mechanisms that enable cancer cells to resist anoikis, with a focus on mechanotransduction. We discuss the roles of integrin signaling, the YAP/ TAZ pathway, the mechanosensitive ion channels, and actomyosin contractility in sustaining survival under mechanical stress conditions. Furthermore, we highlight the emerging contribution of soluble mediators, particularly the myokine irisin, which acts as mechanical mimetics by activating survival pathways typically triggered by matrix engagement. We also examined how mechanical heterogeneity across tumor types and metastatic routes shapes context-specific adaptation strategies. By bridging physical forces and cell survival signaling, this review underscores mechanostransduction as fundamental driver of metastatic competence and a promising target for therapeutic intervention
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
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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