1,721,138 research outputs found
Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model
No full textIn the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the dependency on time, temperature and particle-deposit composition explicitly. Indeed, such a model lies in the field of the rheology of visco-elastic solids which the author of this dissertation refers to in the following chapters. Particle adhesion is calculated by imposing an energy balance between kinetic energy, energy loss and the work of adhesion at the impact while the hard sphere approach is applied to model particle to particle collision. These calculations eventually return as result the particle tangential and normal to impact surface (energy) restitution coefficients. Particular attention was given to the implementation of the solution algorithms and the development of a computational strategy to investigate in detail both particle trajectories, properties and deposit locations. The development of the solution algorithms is twofold, to investigate both particle deposition and the deposit growth applying different computational strategies and algorithms which are usually employed separately (competitor algorithm solution). In the "integrated" approach proposed here, these strategies are coupled (staged partner algorithm solution) according to a sequential use (staged procedure), to provide detailed and time dependent result data. A novel computer program for Lagrangian particle tracking on unstructured meshes, was developed to investigate particle deposition in Computational Fluid Dynamics (CFD) data post-processing. Developing a particle tracker program as a separate and CFD independent computer code has overcome several limitations in particle modelling which are present in commercial CFD code (i.e. non-open source) even though, on the other hand, it required to develop a robust in-cell particle location algorithm as well as an accurate and efficient particle interpolation and integration time scheme. All these characteristics and requirements have driven the author in the development of the Particle Post-Processor software, nicknamed P³, which is capable of calculating particle trajectories and deposition, deposit growth and particle-particle interaction (hard spheres model). A specific particle in-cell detection algorithm, to locate the cell hosting the particle, was developed to upload and elaborate results from commercial CFD codes for hybrid-unstructured meshes. Three commercial CFD codes have been tested. Particle tracking on both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) results was successfully performed and compared. Numerical results are substantially in good agreement with the experimentals.Process and EnergyMechanical, Maritime and Materials Engineerin
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
Morphological and histochemical features of the luminal epithelium of caudal region of the equine oviduct
No full textThe caudal region of the mammalian oviduct includes the isthmus and utero-tubal junction segments. In equine oviduct a few studies have been performed on the isthmus by means of scanning electron microscopy (SEM) and lectin histochemistry, whereas studies on the interstitial segment of isthmus (ISI) (corresponding to the cow and pig utero-tubal junction) are lacking. These two segments of mare oviducts were processed for SEM and electron transmission microscopy as well as for lectin histochemistry. The ISI showed a narrower lumen and a taller epithelium than isthmus. The epithelium of the both regions contained electron-lucent ciliated cells and two sub-types of non-ciliated (secretory) cell. Most secretory cells in the ISI showed granules characterized by a dense core surrounded by less electron-dense material, whereas a few cells showed an electron-dense cytoplasm containing small electron-dense granules. In the isthmus non-ciliated cells were moderately electron-dense and the two sub-types differed in the number and the electron-density of the granules. Lectin histochemistry showed Galβ1,3GalNAc and sialic acid-Galβ1,3GalNAc in the ISI and Neu5Acα2,6Gal/GalNAc in both segments. These results suggest that during their passage through the ISI and the isthmus spermatozoa move in two different intraluminal milieu which contribute to ensuring the effective condition of the sperm when ovulation occurs
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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