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Kinetic study of the degradation of sulfamethoxazole by uv light combined with H2O2 and photo-fenton treatment
No full textSulfamethoxazol (SMX) is een sulfonamide antibioticum dat oraal wordt toegediend. Via het rioleringssysteem komt het na excretie terecht in afvalwaterzuiveringsinstallaties. De biologische zuivering van de moderne zuiveringsinstallaties verwijdert het SMX niet efficiënt door het bacteriostatisch effect van het antibioticum. Ook is het effect van langdurige blootstelling aan SMX op het aquatisch milieu en op de menselijke gezondheid niet bekend. Deze thesis beschrijft de degradatie van SMX door een degradatie schema voor te stellen en fysische en chemische parameters (kleur, troebelheid, aromaticiteit) kinetisch te modelleren.
Een 1.0 L oplossing van 50 mg L-1 SMX reageerde met 100 mM H2O2 in een fotokatalytische reactor met een 150W kwik UV lamp. De temperatuur was constant op 25°C. De pH varieerde tijdens verschillende testen tussen 2.0 en 12.0 en bleef constant tijdens de reactie door het toevoegen van 0.1 M NaOH en HCl. In verdere testen bevatte de oplossing ook Fe2+ als katalysator en het effect van de hoeveelheid katalysator, de concentratie H2O2 en pH op de kinetiek werd onderzocht. De stalen werden geanalyseerd met behulp van ionchromatografie en meting van de fysische en chemische parameters.
Het effect van pH op het degradatie schema werd toegewezen aan de ionizatie van het SMX. Om de parameters van de UV/H2O2 reactie te beschrijven werd een pseudo-eerste orde model gebruikt, terwijl voor de foto-Fenton reactie een tweede orde model werd opgesteld. Deze bevindingen zijn in lijn met de resultaten in de literatuur
Kinetic study of the degradation of sulfamethoxazole by uv light combined with H2O2 and photo-fenton treatment
No full textSulfamethoxazol (SMX) is een sulfonamide antibioticum dat oraal wordt toegediend. Via het rioleringssysteem komt het na excretie terecht in afvalwaterzuiveringsinstallaties. De biologische zuivering van de moderne zuiveringsinstallaties verwijdert het SMX niet efficiënt door het bacteriostatisch effect van het antibioticum. Ook is het effect van langdurige blootstelling aan SMX op het aquatisch milieu en op de menselijke gezondheid niet bekend. Deze thesis beschrijft de degradatie van SMX door een degradatie schema voor te stellen en fysische en chemische parameters (kleur, troebelheid, aromaticiteit) kinetisch te modelleren.
Een 1.0 L oplossing van 50 mg L-1 SMX reageerde met 100 mM H2O2 in een fotokatalytische reactor met een 150W kwik UV lamp. De temperatuur was constant op 25°C. De pH varieerde tijdens verschillende testen tussen 2.0 en 12.0 en bleef constant tijdens de reactie door het toevoegen van 0.1 M NaOH en HCl. In verdere testen bevatte de oplossing ook Fe2+ als katalysator en het effect van de hoeveelheid katalysator, de concentratie H2O2 en pH op de kinetiek werd onderzocht. De stalen werden geanalyseerd met behulp van ionchromatografie en meting van de fysische en chemische parameters.
Het effect van pH op het degradatie schema werd toegewezen aan de ionizatie van het SMX. Om de parameters van de UV/H2O2 reactie te beschrijven werd een pseudo-eerste orde model gebruikt, terwijl voor de foto-Fenton reactie een tweede orde model werd opgesteld. Deze bevindingen zijn in lijn met de resultaten in de literatuur
Kinetic modelling of colour and turbidity formation in aqueous solutions of sulphamethoxazole degraded by UV/H<sub>2</sub>O<sub>2</sub>
No full textThe oxidation of sulphamethoxazole medicine (SMX) has been studied by means of UV/H2O2 conducting at a controlled pH between 2.0 and 12.0 and oxidant ratios of 500 mol H2O2/mol SMX. It is verified that operating at pH = 2.0 the highest rates of SMX degradation (74%) and loss of aromaticity (64%) are obtained. During the process, a strong brown tint and high turbidity are generated in the water depending on the pH, as it affects the chemical speciation of the dissociable compounds. The colour intensity of the water increases from pH = 2.0 (light brown, 3.5 NTU) to a maximum value at pH = 4.0 (dark brown, 42 NTU), when the neutral SMX species is almost 100%. Under these conditions, the formation of carboxylic acids (acetic and oxalic) and nitrate ion are minor. Conducting at higher pH, hue decreases, obtaining at pH = 12.0 a light yellow water (5 NTU) when the anionic SMX predominates. Thus, the maximum formation of nitrate ion occurs under these conditions. A pseudo-first order kinetic modelling is proposed for the loss of aromaticity and colour and turbidity formation in water, where the kinetic parameters are expressed as a function of the applied pH, being the pseudo-first-order rate constants (min(-1)): karom = 0.0005 pH(2) - 0.0106 pH + 0.0707 ; k(colour) = 0.0011 pH(2) - 0.02 pH + 0.1125 and k(NTU) = 0.06 min(-1). [GRAPHICS] .This work was supported by the University of the Basque Country UPV/EHU through the Project ‘Environmental Studies and Energy Efficiency (GIU20/056)’
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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