Electricité / Paris : Nathan (1997)

Titre : Electricité : Courant continu, courant alternatif Type de document : texte imprimé Editeur : Paris : Nathan Année de publication : 1997 Collection : Etapes Sous-collection : Mémento num. 50 Importance : 127 p. Présentation : ill. Format : 22 cm. ISBN/ISSN/EAN : 2-09-177981-4 Note générale : Exercices résolus Langues : Français (fre) Catégories : Courants alternatifs Courants continus Electricité Index. décimale : 621.3 Electrotechnique, électronique, télécommunications Résumé : Cet ouvrage s'adresse aux professionnels de l'électricité ; il est également destiné à tous ceux qui souhaitent se familiariser avec l'électricité. Parce qu'il regroupe les résultats essentiels de l'électricité élémentaire, cet ouvrage peut aussi constituer un aide-mémoire très utile aux étudiants et aux auditeurs de la formation permanente. Les auteurs ont choisi de privilégier l'observation et l'exploitation d'expériences plutôt que l'exposé de théories et le recours aux mathématiques. Ces connaissances peuvent suffire pour acquérir une bonne maîtrise de nombreux équipements électriques, la complexité des systèmes électriques excluant de plus en plus la possibilité d'acquérir les capacités nécessaires pour le dépannage et même parfois la maintenance. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=70

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Examination of haloversatile bacteria on salted goatskin and inactivation of haloversatile bacteria via direct electric current / S. Kose in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIX, N° 4 (04/2024)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIX, N° 4 (04/2024) . - p. 184-197 Titre : Examination of haloversatile bacteria on salted goatskin and inactivation of haloversatile bacteria via direct electric current Type de document : texte imprimé Auteurs : S. Kose, Auteur ; P. Yilmaz, Auteur ; Meral Birbir, Auteur ; Yasar Birbir, Auteur Année de publication : 2024 Article en page(s) : p. 184-197 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries -- Comptage Bactéries -- Identification Bactéries haloversatiles Caractérisation Courants continus Cuirs et peaux -- Analyse Cuirs et peaux -- Détérioration Cuirs et peaux de chèvres Enzymes microbiennes Peaux salées Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Haloversatile bacteria are among the commonly found microorganisms that have the potential to damage hides and skins in the leather industry. Therefore, the objective of this study was to investigate the presence of haloversatile bacteria on salted goatskins, to characterize these microorganisms through the use of molecular and conventional test methods, to detect their impact on the skins, and finally find an effective solution to inactivate these microorganisms. Haloversatile bacteria were common inhabitants at salted goatskin samples obtained from the Tuzla Organized Leather Industry Zone in Türkiye. Total numbers of haloversatile bacteria, proteolytic haloversatile bacteria, and lipolytic haloversatile bacteria on ten salted goatskin samples ranged from 7×104 to 2.7×105 CFU/g, 1×104 to 8×104 CFU/g, and 1×104 to 1.3×105 CFU/g, respectively. In the present study, 88% of the isolates were protease-positive, 69% were lipase-positive, 8% were xylanase-positive, 27% were caseinase-positive, 23% were amylase-positive, 8% were DNase-positive, 31% were cellulasepositive, 54% were urease-positive, 100% were catalase-positive, and 54% were oxidase-positive. The bacterial isolates showed positive reactions for the utilization of different amino acids such as glycine, L-cysteine, L-proline, and L-threonine, having the highest rates of 88%, 80%, 80%, and 80%, respectively. However, L-histidine had a lower positive reaction rate of 31%. The halophilic bacterial isolates exhibited positive reactions for the utilization and acid production from different types of sugar, with glucose having the highest positive reaction rate of 81%, followed by maltose at 73%, xylose at 58%, galactose at 46%, and lactose at 42%. Haloversatile enzymeproducing bacteria were identified using biochemical and molecular methods, resulting in the identification of 17 different species. Micrographs obtained from the scanning electron microscope revealed the damage inflicted on the fresh goatskin structure by haloversatile bacteria. A direct electric current of 2.2 A was applied to the mixed culture of haloversatile bacteria for 25 minutes to find an effective inactivation method. The total count of the mixed culture of haloversatile bacteria decreased from 7.3×106 CFU/mL to 4 CFU/mL within 16 minutes. All seventeen haloversatile bacteria in the mixed culture were killed within 19 minutes. Note de contenu : - Collection of salted goatskin samples from tanneries and measurement of pH values - Determination of the total numbers of haloversatile bacteria, proteolytic, and lipolytic haloversatile bacteria on the salted goatskin samples - Isolation of haloversatile bacteria - Haloversatile bacterial identification - Determination of optimal growth conditions for haloversatile bacteria - Investigation of enzymatic properties of haloversatile bacteria - Utilization of different amino acids and carbon sources by haloversatile bacteria - Examination of the damage caused by enzyme-producing haloversatile bacteria on the goatskin sample using scanning electron microscope - Destruction of haloversatile bacteria using electric current - Examination of haloversatile bacterial cells before and after treatment with direct electric current using scanning electron microscopy - Table 1 : The salted skin sample codes, ph of salted skin samples, total haloversatile, total proteolytic haloversatile, total lipolytic haloversatile bacterial counts on salted goatskin samples (CFU/g) - Table 2 : The isolate codes, phylogenetically similar species, length (bp), similarity (%), accession number of haloversatile isolates obtained from salted goatskin samples - Table 3 : The effects of pH, NaCl contents and temperature values on the growth of haloversatile bacterial isolates - Table 4 : Enzymatic characteristics of haloversatile isolates obtained from salted goatskin samples - Table 5 : Utilization of different sugars and amino acids by haloversatile isolates - Table 6 : The pH values, temperature, voltage and the total counts (CFU/mL) of enzyme producing haloversatile bacteria in the direct electric current treatment En ligne : https://drive.google.com/file/d/1WN-TWYW9l8-TRlCWsX0w8KSiISJyWWKx/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40826 [article]

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Extracellular protease activities of extremely halophilic archaea and their control via direct electric current / Meral Birbir in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 2 (03-04/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 2 (03-04/2008) . - p. 53-58 Titre : Extracellular protease activities of extremely halophilic archaea and their control via direct electric current Type de document : texte imprimé Auteurs : Meral Birbir, Auteur ; Z. B. Ozdogru, Auteur ; Yasar Birbir, Auteur ; Ayse Ogan, Auteur Année de publication : 2008 Article en page(s) : p. 53-58 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bactéries halophiles Bain de saumure Courants continus Cuirs et peaux -- Conservation Enzymes protéolytiques Une enzyme protéolytique est une enzyme capable de couper une protéine en plusieurs fragments ou peptides. La trypsine, la papaïne, la pepsine, la chymotrypsine, la plasmine, la subtilisine... sont capables de couper une protéine, chaque enzyme étant spécifique de certains sites particuliers de cette protéine. C'est ainsi, par exemple, qu'une immunoglobuline G est découpée par la papaïne en un fragment Fc et deux fragments Fab, comme l'a montré Porter en 1959. Microbiologie Peptidases Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Proteolytic enzymes which are produced by extremely halophilic Archaea present in salt may cause serious damage on salted hides and may result in significant economic losses in the leather industry. Hence, protease activities of 24 protease producing extremely halophilic archaeal strains isolated from Tuz Lake, Kaldırım and Kayacık salterns and Tuzköy salt mine were determined in this study. The protease activities of Tuz Lake, Kaldırım saltern, Kayacık saltern and Tuzköy salt mine strains were found as between 80.0 and 83.3, 81.1 and 83.8, 83.3 and 83.4, 82.0 and 83.4 Units, respectively. To prevent proteolytic haloarchaeal damage on brine cured hides, the protease producing strains were treated with 0.5A direct electric current for 20min. Although proteolytic strains of Tuz Lake and Tuzköy salt mine in the liquid gelatin media were killed by 0.5A direct electric current within 15min, 10min direct electric current treatment were enough to kill all proteolytic strains of Kaldırım and Kayacık salterns. Also, the effect of 0.5A direct electric current on protease activities of the test strains was examined during 20min treatment in this study. It was found that 0.5A direct electric current caused a slight decrease on protease activities of the test strains. Therefore, it is necessary to kill protease producing strains in brine solution with direct electric current before the excretion of their protease into the brine solution. Note de contenu : - Extremely halophilic strain - Protease activities of the extremely halophilic strains - Inactivation of the test strains with 0.5A direct electric current - Table 1 : Protease activities of extremely halophilic Archaea isolated from Tuz Lake, Kaldırım and Kayacık Salterns and Tuzköy Salt Mine - Table 2 : Voltage, temperature and rf values of 4 mixed proteolytic halophilic Archaea inactivated in the liquid gelatin media by 0.5A direct electric current within 20 minutes - Table 3 : The effect of 0.5A direct electric current on protease activities of some of the test strains during 20 minutes treatment En ligne : https://drive.google.com/file/d/1gBbMoBdjmpLA6cnCaGdQjxhmAhOnxKZz/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38930 [article]

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Inactivation of moderately halophilic soak liquor / Pinar Yilmaz in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 108, N° 4 (07-08/2024)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 108, N° 4 (07-08/2024) . - p. 203-209 Titre : Inactivation of moderately halophilic soak liquor Type de document : texte imprimé Auteurs : Pinar Yilmaz, Auteur ; Meral Birbir, Auteur ; Yasar Birbir, Auteur Année de publication : 2024 Article en page(s) : p. 203-209 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bactéries -- Inactivation Bactéries halophiles Courants continus Courants électriques Cuirs et peaux -- Conservation Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Salted animal skins and preservation salt may contain various microorganisms in the leather industry. Microbial activities on the raw and preserved hides and skins may cause adverse effects during salting process, storage period, and soaking process on leather. Antimicrobial applications have a critical importance to prevent damage of microorganisms during these applications. Hence, the aim of the present study was to inactivate moderately halophilic isolates by 2A direct electric current treatment which cause skin degradation. Each moderately halophilic bacterial species (Terribacillus halophilus SLMHB10, Vibrio alginolyticus SLMHB12, Vibrio parahaemolyticus SLMHB13), which were previously isolated from soak liquor samples, and their mixed culture were separately treated with 2A DC in test media containing 25% NaCl solution, 10% NaCl solution, both 4% NaCl and organic substance. Although Terribacillus halophilus SLMHB10, Vibrio alginolyticus SLMHB12, and the mixed culture of three species were completely killed in 18 min, Vibrio parahaemolyticus SLMHB13 were completely killed in 12 min. As a conclusion, 2A direct electric current application were found fairly effective to kill moderately halophilic isolates recovered from soaking liquors in the leather industry. Note de contenu : - Test bacteria - Application of direct electric current on test isolates - Table 1 : Bacterial counts of the each isolate and mixed culture of moderately halophilic bacteria treated with 2 A direct electric current in 25 % NaCl saline solution - Table 2 : Bacterial counts of the each isolate and mixed culture of moderately halophilic bacteria treated with 2 a direct electric current in 10% nacl saline solution - Table 3 : Bacterial counts of the each isolate and mixed culture of moderately halophilic bacteria treated with 2 a direct electric current in 4% nacl + organic substance En ligne : https://drive.google.com/file/d/1MkQ7UjELSuHUtBwgly1H5I5axsfvbDnX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=41407 [article]

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Negative effects of haloversatile bacteria in salt on skins and their control with direct electric current in the leather industry / Haider Sabah Abdulhusein in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 107, N° 6 (11-12/2023)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 107, N° 6 (11-12/2023) . - p. 207-214 Titre : Negative effects of haloversatile bacteria in salt on skins and their control with direct electric current in the leather industry Type de document : texte imprimé Auteurs : Haider Sabah Abdulhusein, Auteur ; Pinar Caglayan, Auteur ; Meral Birbir, Auteur ; Yasar Birbir, Auteur Année de publication : 2023 Article en page(s) : p. 207-214 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bactéries haloversatiles Courants continus Cuirs et peaux -- Conservation Cuirs et peaux de chèvres Cuirs et peaux de moutons Microbiologie Sels de sodium Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The salt preservation method has been used for a long time in the leather industries with salt applied to raw skins and hides in order to control bacterial activity and to remove the moisture found in the skin structure. It is known that the salt used in curing process contains many halophilic bacterial species. During the salting process, skins and hides might be contaminated with these micro-organisms. The goal of this research was to determine factors including the pH of salt samples, total count of haloversatile bacteria, proteolytic haloversatile bacteria, and lipolytic haloversatile bacteria found in these samples and to isolate, and identify haloversatile bacteria from the salt samples, to test their ability to use various amino acid and sugar sources, to characterise their enzymatic properties, to investigate their adverse effects on sheepskinand goatskin samples using a scanning electron microscopy. In addition, 2.5A direct electric current was applied against mixed culture of enzyme-producing haloversatile bacteria in 15% NaCl solution to search for an alternative environmentally friendly preservation method for skin/hide curing. The pH values of salt samples were found to be between 7.60 and 8.04. The total counts of haloversatile bacteria, proteolytic haloversatile bacteria and lipolytic haloversatile bacteria were found to be 6 × 103CFU/g to 1.3 × 105CFU/g; 1×103-7×103CFU/g and 1.4 × 103-3.1 × 104CFU/g, respectively. 35 haloversatile bacteria belonging to ten different genera (Staphylococcus, Corynebacterium, Peribacillus, Lysinibacillus, Kocuria, Paenibacillus, Bhargavaea, Bacillus, Pseudomonas and Micrococcus) were isolated and identified from the salt samples. The ability of haloversatile bacteria to use sugars and amino acids varied from one genus to another genus. While catalase, esterase, urease, protease, caseinase, lipase, xylanase, cellulase, amylase, DNase and oxidase enzymes were produced among the isolates, pullulanase enzyme was not produced. The scanning electron microscope micrographs showed that enzyme-producing haloversatile bacteria had significant effects on goatskin and sheepskin. The total number of the mixed culture was reduced from 3.6 × 106CFU/mL to 4×101CFU/mL within 17 minutes, and all cells were completely killed within 21 minutes. The scanning electron micrographs showed that the structure and the organoleptic characterictics of bacteria treated sheepskin and goatskin samples were negatively changed at the end of 40-days storage. Note de contenu : - Salt sample collection and measuring pH value of salt samples - Determination of the total numbers of haloversatile bacteria in the salt samples - Determination of the total numbers of proteolytic and lipolytic haloversatile bacteria in salt samples - Isolation of haloversatile bacteria - Identification of haloversatile isolates according to 16S rRNA gene sequence analyses - Nucleotide accession number - Effects of different NaCl concentrations, pH values and temperature on haloversatile bacterial growth - Investigation of enzymatic properties of haloversatile bacteria - Utilisation of different amino acids and different carbon sources by haloversatile bacteria - Investigation the effects of the mixed culture of enzyme producing haloversatile isolates on sheepskin and goatskin - Extermination of haloversatile bacteria by direct electric current - Investigation of the bacterial cells before and after the treatment with direct electric current by scanning electron microscopy - Table 1 : The pH values, total counts of haloversatile bacteria, proteolytic haloversatile bacteria and lipolytic haloversatile bacteria in the salt samples - Table 2 : The effects of pH, NaCl contents and temperature values on bacterial growth - Table 3 : Enzymatic properties of haloversatile bacterial isolates - Table 4 : Utilization of different amino acids by haloversatile isolates - Table 5 : Utilisation of different sugars by haloversatile isolates - Table 6 : The pH values, temperature and the total counts (CFU/mL) of enzyme producing haloversatile bacteria in the direct electric current treatment En ligne : https://drive.google.com/file/d/1qRfWv_CwzI3WQkn8QhrK0n0Rq2zPAjwb/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40239 [article]

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