1,721,030 research outputs found
Integrated air stripping for remediation of soils contaminated by organic compounds
No full textThis paper presents the results of a laboratory scale investigation on the remediation of a soil contaminated by a mixture of organic compounds using a two-step process consisting of stripping and biofiltration. The biofilter was packed with the soil under examination in order to use autochthonous microorganisms. To assess the effects of both temperature and superficial velocity of the air stream on process performance different sets of experimental tests were carried out at two air temperatures (50 and 80 degrees C), and at two superficial air velocities (41.0 and 82.0 m h(-1)), corresponding to apparent air residence times in the biofilter column of 38 and 19s respectively. The stripping rate proves to be inversely correlated with the soil-water partitioning coefficient, while no evident correlation was found with the Henry coefficient. It can therefore be concluded that soil-water partitioning is limited by mass transfer while air-water partitioning reaches equilibrium. Temperature influences both stripping rate in the stripping column and degradation capacity in the biofilter. A stripping temperature of 80 degrees C combined with a biofiltration temperature of WC provides the best process performance. (c) 2007 Society of Chemical Industry
Mathematical modelling and simulation of phenol degradation in biofilters
No full textA mathematical model consisting of mass balance equations and accounting for reaction, mass transfer and axial dispersion is presented to describe the steady-state degradation of phenol in a biofilter. The reliability of model simulations was tested using experimental data from a laboratory-scale biofilter bed column, packed with a mixture of peat and glass beads and inoculated with a pure strain of Pseudomonas putida. Comparison of model estimates with experimental concentration profiles of the pollutant along the biofilter height proves that the model is appropriate to interpret the experimental results and simulate the process. The model can therefore be used as a design tool to predict the effect of varying operating conditions (e.g. inlet pollutant concentration, gas velocity) on reactor performance (e.g. degradation capacity and efficiency). Sensitivity analysis of the model shows that parameters such as dispersion coefficient and maximum specific growth rate have to be accurately estimated for the correct prediction of reactor performance. (C) 2004 Elsevier B.V. All rights reserved
Generalizations of Unifications
No full textWe define a general notion of (syntactic) unification, whose special cases are matching, unification, semi-unification, and weak-unification. We settle all the implications between the various cases of unification leading to a classification and a decidability result. We show that some distinctions holding for finite terms collapse for infinite terms. We give some positive results on the existence of most general weak-unifiers
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
STIPSI DA DEFECAZIONE OSTRUITA: CAUSA ORGANICA O ALTERAZIONE FUNZIONALE? ATTUALI ORIENTAMENTI TERAPEUTICI E RIABILITATIVI
No full textVariations 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
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