A study of the realistic strength of leather : true stress / Bahri Basaran in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 10 (10/2012)

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVII, N° 10 (10/2012) . - p. 342-347 Titre : A study of the realistic strength of leather : true stress Type de document : texte imprimé Auteurs : Bahri Basaran, Auteur ; Sevgi Nalbat, Auteur Année de publication : 2012 Article en page(s) : p. 342-347 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Contraintes (mécanique) Cuirs et peaux -- Propriétés mécaniques Duncan, Test de Durée de vie (Ingénierie) Essais dynamiques Maroquinerie Traction (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Strength deals with the durability of materials during usage and therefore is an important criterion for performance evaluation. Leather goods, which continue to be preferred by many over artificial substitutes, need to exhibit durable material performance. Strength testing, as related to an understanding of the endurance against force, is an important component of overall material behavior. Therefore, tensile testing should be well developed so as to analyze the properties of finished leathers and acquire realistic practical data. This study deals, in detail, with the evaluation of tensile properties considering the differences between engineering stress and true stress. In this examination of tensile behaviors three groups of garment leathers with different finishes (aniline, semi-aniline, and full pigmented finishes) were used. The samples were evaluated comparing engineering stress and true stress. In a Completely Randomized Design study, the statistical differences were calculated by the Duncan test in the level of P≤0.05. Thereby, statistically significant differences between engineering stress and true stress between each of the three groups was verified. Note de contenu : - Table I : Tensile strength properties of finished leathers - Table II : The results of the statistical analyses obtained from the Duncan test with a significance level of P≤0.05 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15936 [article]

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UV protection against photoageing of garment leathers by ZnO nanoparticles : application of nano ZnO in finishing process as photocatalyst / Bekir Yilmaz in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 6 (11-12/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 6 (11-12/2016) . - p. 321-326 Titre : UV protection against photoageing of garment leathers by ZnO nanoparticles : application of nano ZnO in finishing process as photocatalyst Type de document : texte imprimé Auteurs : Bekir Yilmaz, Auteur ; Ersin Onem, Auteur ; Ali Yorgancioglu, Auteur ; Eser Eke Bayramoglu, Auteur Année de publication : 2016 Article en page(s) : p. 321-326 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse de variance En statistique, l'analyse de la variance (terme souvent abrégé par le terme anglais ANOVA : ANalysis Of VAriance) est un ensemble de modèles statistiques utilisés pour vérifier si les moyennes des groupes proviennent d'une même population. Les groupes correspondent aux modalités d'une variable qualitative (p. ex. variable : traitement; modalités : programme d'entrainement sportif, suppléments alimentaires ; placebo) et les moyennes sont calculés à partir d'une variable continue (p. ex. gain musculaire). Ce test s'applique lorsque l'on mesure une ou plusieurs variables explicatives catégorielles (appelées alors facteurs de variabilité, leurs différentes modalités étant parfois appelées "niveaux") qui ont de l'influence sur la loi d'une variable continue à expliquer. On parle d'analyse à un facteur lorsque l'analyse porte sur un modèle décrit par un seul facteur de variabilité, d'analyse à deux facteurs ou d'analyse multifactorielle sinon. (Wikipedia) Cuir -- Teneur en chrome hexavalent Cuirs et peaux -- Analyse Cuirs et peaux -- Finition Duncan, Test de Essais accélérés (technologie) Nanoparticules Oxyde de zinc Photocatalyse Spectrophotométrie Statistique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this study, zinc oxide nano-particles, known to have photocatalytic and high UV protection properties, were used in the finishing process to prevent chromium(VI) formation as a result of photoageing in the garment leather products. The researches were carried out on the chrome-tanned garment leather. Nano zinc oxide at the proportions of 0.25%, 0.5% and 1% on nitrocellulose (N/C) emulsion amount were used in the finishing process of leathers. The finished garment leathers were exposed to an artificially accelerated ageing process at 80°C for 24 hours and 80°C/UV for 24 hours. Cr(VI) amounts in each leather sample were evaluated in compliance with ISO/FDIS 17075 standard test method based on the reaction of chromium(VI) with diphenylcarbazide and subsequent colorimetric determination at 540nm by using a double beam Shimadzu 1601 UV visible region spectrophotometer. The leathers finished using nano ZnO were compared to control samples and the way in which ZnO nanoparticles affect Cr(VI) formation was statistically examined by the analysis of variance (ANOVA) and Duncan test. According to research results, it was determined that Cr(Vl) amounts arising in the garment leathers after photoageing were rather high and that the use of nano zinc oxide in finishing process substantially eliminated Cr(VI) formation statistically by providing high UV protection. 18,31 ± 2.46ppm of Cr(Vl) occured under 80°C/UV for 24 hours was decreased to less than 3ppm by 1% of nano ZnO. Using 0.25% and 0.5% of nano ZnO on the amount of N/C emulsion applied also reduced the levels of Cr(VI) to under 3ppm. Note de contenu : - Materials - Finishing process - Accelerated ageing treatment - Chromium(VI) analysis in leather samples - Statistical analysis En ligne : https://drive.google.com/file/d/1qbW5iXWrsAc8w1-UC2R8g8eRvnV1dGRe/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27668 [article]

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