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Etude d'une huile biodégradable à base de Jatropha curcas comme matériau isolant pour transformateurs de puissance
No full textCe travail porte sur la caractérisation physico-chimique de l'huile de Jatropha Curcas et sa capacité à remplacer l'huile minérale dans les transformateurs de puissance. Ce produit présente plusieurs avantages sur les autres huiles végétales comme l'huile de palme ou l'huile de colza, qui recommandent sa production et son utilisation. En effet, la plante de Jatropha Curcas peut être cultivée sur des sols pauvres à faibles précipitations, évitant ainsi d'utiliser des sols plus fertiles pour sa culture permettant ainsi aux petits exploitants de réserver leurs terres aux cultures de base. Cette plante peut pousser facilement dans des zones où les niveaux de précipitations annuelles sont nettement inférieures à celles requises par d'autres espèces telles que le colza, le tournesol, le soja, le maïs, le palmier à huile et d'autres. Elle peut être cultivée sur tous les types de sol en Indonésie, même sur des terres arides, dans de nombreuses régions de l'Indonésie orientale, inexploitées en raison des difficultés à planter d'autres cultures. En outre, l'huile de Jatropha Curcas est un produit non alimentaire. En faisant subir à l’huile de Jatropha Curcas brute une estérification à base alcaline avec de l'hydroxyde de potassium (KOH), on obtient de l’huile de méthylester de Jatropha Curcas (JMEO) dont la viscosité et l’acidité sont acceptables pour les équipements à haute tension en particulier pour les transformateurs de puissance. Les propriétés physico-chimiques et électriques de JMEO ont été mesurées ainsi que celles de l'huile minérale (MO) pour la comparaison. Pour les propriétés physico-chimiques, il s’agit de la densité relative, la teneur en eau, la viscosité, l'acidité, l'indice d'iode, la corrosivité, le point d'éclair, le point d'écoulement, la couleur, l'examen visuel, et la teneur en ester méthylique. Quant aux propriétés électriques, elles concernent la rigidité diélectrique sous différentes formes de tension (alternative, continu et choc de foudre), les phénomènes de pré-claquage et de claquage sous choc de foudre, les décharges glissantes sur les surfaces de carton comprimé, immergé dans JMEO et MO. Les résultats obtenus montrent que les tensions de claquage moyennes en continu et en choc de foudre des huiles JMEO et MO sont très proches ; la tension de claquage moyenne de JMEO est même plus élevée que celle de l'huile minérale (de type naphténique). La mesure des tensions de claquage des mélanges d'huiles «80% JMEO + 20% MO» et «50% JMEO et 50% MO» montrent que la tension de claquage du mélange «80% JMEO + 20% MO» est toujours supérieure à celle de l'huile minérale sous tensions alternative et continue. Cela indique que le mélange d'huile minérale et de JMEO avec un rapport de 20:80 ne dégrade pas ses performances. Le mélange d'huiles peut se produire lors du remplacement de l'huile minérale par JMEO dans les transformateurs installés et en exploitation. L'analyse des caractéristiques des streamers (la forme, le temps d'arrêt, le courant associé et la charge électrique) se développant dans les huiles JMEO et MO sous tension impulsionnelle de foudre, montre une grande similitude. Aussi, la longueur finale (Lf) et la densité des branches des décharges surfaciques se propageant sur le carton comprimé immergé dans l'huile de Jatropha Curcas de méthylester (JMEO) et de l'huile minérale (MO), sous tensions de choc de foudre positif et négatif (1,2/50 μs), pour deux configurations d'électrodes divergentes (électrode pointe haute tension perpendiculaire et tangente au carton, respectivement), sont fortement influencées par l'épaisseur du carton comprimé. Pour une épaisseur donnée, Lf augmente avec la tension et décroît lorsque l'épaisseur augmente. Lf est plus long lorsque la pointe est positive que lorsque la pointe est négative. Pour une tension et une épaisseur du carton comprimé donnée, les valeurs de Lf dans l’huile minérale et l’huile JMEO sont très proches. [...]This work is aimed at the investigation of the physicochemical characterization of Jatropha Curcas seeds oil and its capacity to be an alternative option to replace mineral oil in power transformers. This product presents several advantages that recommend both its production and usage over those of other vegetable oils as crude palm oil and rapeseeds oil. Indeed, it may be grown on marginal or degraded soils avoiding thus the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops; and it will readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as palm oil, rape-seeds oil, sunflower oil, soybeans oil, corn oil and others. For instance, these plants can grow on all soil types in Indonesia, even on barren soil. The barren soil types can be found in many parts of eastern Indonesia that remain untapped because of the difficulty planted with other crops. Moreover, jatropha curcas oil is nonfood crops. Jatropha Curcas oil was processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce Jatropha Curcas methyl ester oil (JMEO) has a viscosity and a acidity that are acceptable for high voltage equipment especially in power transformer. The physicochemical and electrical properties of JMEO were measured as well as those of mineral oil (MO) for comparison. The physicochemical properties cover relative density, water content, viscosity, acidity, iodine number, corrosivity, flash point, pour point, color, visual examination, and methyl ester content. Meanwhile the electrical properties cover dielectric strength under AC, DC and lightning impulse voltages, pre-breakdown / streamers under lightning impulse voltage, creeping discharge over pressboard immersed in JMEO and MO. The obtained results show that the average DC and lightning impulse breakdown voltages of JMEO and MO are too close, even the average AC breakdown voltage of JMEO are higher than that of mineral oil (napthenic type). The measurement of breakdown voltages of two oil mixtures namely “80% JMEO + 20% MO” and “50% JMEO and 50% MO” shows that the breakdown voltage of the first mixture (i.e., “80%JMEO+20%MO”) is always higher than that of mineral oil under both AC and DC voltages. This indicates that mixing 20:80 mineral oil to JMEO ratio does not degrade its performance. The mixing of oils can occur when replacing mineral oil by JMEO in installed transformers. The analysis of the streamers characteristics (namely; shape, stopping length, associated current and electrical charge) developing in JMEO and MO under lightning impulse voltages, shows that these are too close (similar). It is also shown that the stopping (final) length Lf and the density of branches of creeping discharges propagating over pressboard immersed in Jatropha Curcas methyl ester oil (JMEO) and mineral oil (MO), under positive and negative lightning impulse voltages (1.2/50 μs), using two divergent electrode configurations (electrode point perpendicular and tangential to pressboard), are significantly influenced by the thickness of pressboard. For a given thickness, Lf increases with the voltage and decreases when the thickness increases. Lf is longer when the point is positive than with a negative point. For a given voltage and thickness of pressboard, the values of Lf in mineral oil and JMEO are very close. It appears from this work that JMEO could constitute a potential substitute for mineral oil for electrical insulation and especially in high voltage power transformers
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Effect of Low Flow Rate of Air Injection on Remazol Red Degradation in Contact Glow Discharge Electrolysis Reactor
Get PDFBackground and Objective: The plasma electrolysis requires a high amount of energy at the beginning of the process. The purpose of the study was to examine how air injection could reduce the energy of plasma formation. Furthermore, the effect of the flow rate of injected air on hydroxyl radical production and Remazol Red degradation were also studied. Materials and Methods: In this research, the air was injected directly through the glass sheath at the anode in Contact Glow Discharge Electrolysis reactor. Material used were Remazol Red RB-133 200 ppm as synthetic dye waste, Fe2+ 20 ppm as catalyst and Na2SO4 0.02 M as electrolyte solution. Result: For the same energy input, the higher the flow rate of air injection, the radical hydroxyl concentration increased to an optimum point at a certain flow rate. Moreover, the rate of airflow at optimum condition increased with increasing voltage. An airflow rate of 0.05 L/min and a voltage of 600 Volts was the optimum condition. The concentration of hydroxyl radical at this condition produced 19.0849 mmol/L after 30 minutes. Conclusion: This was an increase of 48.43% in comparison with the amount of •OH where air injection was not used. The presence of air injection also increased the degradation of Remazol Red. Within 5 minutes, Remazol Red degradation had reached 86.37% at an airflow rate of 0.05 L/min. This indicated a 53.59% increase compared to the degradation process without air injection
The Application of Catalytic Ozonation Technique using UV and Granular Activated Carbon (GAC) for Eliminating in Waste Phenol, COD, and 1,1,2,2-Tetrachloroethane
Get PDFProcess eliminating compounds of phenol, Chemical Oxygen Demand (COD), and 1,1,2,2-tetrachloroethane using catalytic ozonation technique with catalyst Granular Activated Carbon (GAC) combination with Ultra Violet (UV) light emission performed in this study. This study aimed to obtain the effectiveness of applications catalytic ozonation technique using system configuration Ozone/GAC and Ozone/UV/GAC to eliminate waste phenol 1,1,2,2-tetrachloroethane COD with circulation time (0, 15, 30, 45, 60, and 120 minutes). The wastewater was derived from the wastewater Laboratory of Polyester Industrial in Bogor. The results were analyzed, comprised of COD with Ferrous Ammonium Sulphate (FAS) method, phenol using aminoantipirin method, and 1,1,2,2-tetrachloroethane with Gas Chromatography-Flame Ionization Detector (GC-FID) method. The result of study shown that the configuration of the Ozone/ UV/GAC with an initial concentration of phenol 58,00 mg/L, COD 72,00 mg/L and 1,1,2,2-tetrachloroethane 32,96 mg/L resulted in the percentage of eliminating phenol 57,76%, COD 66,67% and 1,1,2,2-tetrachloroethane 98,74% while the configuration of Ozone/GAC with an initial concentration of phenol 55,00 mg/L, COD 72,00 mg/L and 1,1,2,2-tetrachloroethane 37,70 mg/L resulted in percentage of eliminating phenol 50,91%, COD 55,56% and 1,1,2,2-tetrachloroethane 100%ABSTRAKProses penyisihan senyawa fenol, Chemical Oxygen Demand (COD) dan 1,1,2,2-tetrakloroetana menggunakan teknik ozonasi katalitik dengan katalis Granular Activated Carbon (GAC) yang dikombinasikan dengan emisi sinar Ultra Violet (UV) dilakukan dalam penelitian ini. Tujuan dari penelitian ini untuk memperoleh efektivitas aplikasi teknik ozonasi katalitik menggunakan sistem konfigurasi, yaitu: Ozon/GAC dan Ozon/UV/GAC dalam penyisihan limbah fenol, COD dan 1,1,2,2-tetrakloroetana dengan waktu sirkulasi (0, 15, 30, 45, 60, dan 120 menit). Limbah cair yang digunakan berasal dari limbah cair Laboratorium Industri Polyester di daerah Bogor. Analisis yang dilakukan meliputi analisis COD dengan metode Ferro Ammonium Sulfat (FAS), analisis Fenol dengan menggunakan metode aminoantipirin dan analisis 1,1,2,2-tetrakloroetana dengan metode Gas Chromatography-Flame Ionization Detector (GC-FID). Setelah dilakukan penelitian, diketahui bahwa konfigurasi Ozon/UV/GAC dengan konsentrasi awal fenol 58,00 mg/L, COD 72,00 mg/L dan 1,1,2,2-tetrakloroetana 32,96 mg/L menghasilkan persentase penyisihan senyawa fenol 57,76%, COD 66,67% dan 1,1,2,2-tetrakloroetana 98,74% sedangkan konfigurasi Ozon/GAC dengan konsentrasi awal fenol 55,00 mg/L, COD 72,00 mg/L dan 1,1,2,2-tetrakloroetana 37,70 mg/L menghasilkan persentase penyisihan senyawa fenol 50,91%, COD 55,56% dan 1,1,2,2-tetrakloroetana 100%
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