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Ethiopian Ankelba : an attempt to modernize the cultural leather artifact / Elena Teka Genet in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 12 (12/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 12 (12/2020) . - p. 435-443 Titre : Ethiopian Ankelba : an attempt to modernize the cultural leather artifact Type de document : texte imprimé Auteurs : Elena Teka Genet, Auteur ; Jima Demisie Wegene, Auteur ; Gebrekidan Asfaha Gebrehiwot, Auteur ; Palanisamy Thanikaivelan, Auteur Année de publication : 2020 Article en page(s) : p. 435-443 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse des données Ankelba -- Conception et construction Caractérisation Cuirs et peaux Echantillonnage Ergonomie Objets usuels Production Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Ethiopia has many cultural artifacts made of traditionally processed leathers. Ankelba is one of them and utilized in most part of Ethiopia to carry baby. Here, we report salient features of ankelba and its value in Ethiopia region, demerits of the product and strategies to enhance the design feature of cultural ankelba while maintaining its cultural value. Data were collected through interview guided questionaries' to analyze the causes for the reduced usage of the product. We identified that the traditionally processed cow leathers are heavy with poor color fastness. Further, we recognized that cultural ankelba has flawed design features such as fixed size, improperly placed zagols (sea shell) and uncomfortable strap construction to hold the baby. Here, we present an efficiently designed ankelba overcoming the key deficiencies while preserving the cultural value of local people. This study would pave way for restoration of several cultural artifacts available across the globe. Note de contenu : - MATERIALS AND METHODS : Methods - Data collection and sampling - Geographical domain for the research - Data analysis - Characterization - RESULTS AND DISCUSSION : Traditional leather processing in Ethiopia - Traditional Ankelba production - Major causes for the declined use of traditional Ankelba - Problems associated with the use of traditional leathers for Ankelba production - Problems associated with the traditional design features of Ankelba - Strategy for improving the materials and design of Ankelba - Physical and bulk properties of leathers processed using traditional and modern techniques - Dry and wet rub color fastness of traditionally tanned and modern tanned leathers - Table 1 : Area of data collection and number of participants for data collection - Table 2 : Ankelba size measurements - Table 3 : Leather related problems and their ranking in cultural ankelba - Table 4 : Design related problems and their ranking in cultural ankelba - Fig. 1 : Traditional leather processing in Ethiopia, a) Hide soaking in damped river, b) fleshing, c) cow hides preparation for unhairing, d) oiling and inset, e) oil used for softening leather - Fig. 2 : Ankelba leather preparation steps, a) Leather cutting and dyeing, b) leather strap making, c) button attaching, d) zagol inserting and, f) strap stitching. inset in e) show zagols - Fig. 3 : Major causes for the declined use of traditional ankelba - Fig. 4 : Drawbacks of Ethiopian cultural ankelba, a) inaproppriate size and many zagols and b) un-comfortable neck construction and many buttons DOI : https://doi.org/10.34314/jalca.v115i12.4199 En ligne : https://drive.google.com/file/d/11bhv8vJ2YNLxEDXk6vMvIxuCHtYgRpJZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34996 [article]

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Enzymatic bating technology for wet blue : II. The basic properties and application effectiveness of typical acidic proteases / Xu Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 12 (12/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 12 (12/2020) . - p. 444-453 Titre : Enzymatic bating technology for wet blue : II. The basic properties and application effectiveness of typical acidic proteases Type de document : texte imprimé Auteurs : Xu Zhang, Auteur ; Zhong Xiang, Auteur ; Mengchu Gao, Auteur ; Biyu Peng, Auteur ; Chunxiao Zhang, Auteur Année de publication : 2020 Article en page(s) : p. 444-453 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Peptidases Poids moléculaires Point isoélectrique En biochimie, le point isoélectrique (pI) ou potentiel hydrogène isoélectrique (pHI) est le pH auquel une molécule est sous forme d'ion mixte ou, en physico-chimie, le pH d'une solution aqueuse dans laquelle un solide existe sous un potentiel électrique neutre. En physico-chimie : Selon Bolger, le caractère acide ou basique d'une surface s'exprime par son point isoélectrique " Is ou IEPS (Iso Electric point for the surface) " ou point de charge nulle " PCN ou PZC (Point of Zero Charge) ", défini comme étant le pH de la solution aqueuse dans laquelle le solide existe sous un potentiel électrique neutre. Si le pH de la solution est basique, la surface est acide, et inversement. La différence entre le PZC et l'IEPS est basée sur le phénomène d'adsorption spécifique. On peut considérer que si la grandeur mesurée ne dépend pas de la solution utilisée pour la mesurer (pH, concentration, nature des ions), alors on a affaire à un PZC. Dans le cas contraire, c'est un IEPS que l'on mesure. Par exemple, quand la mesure de goutte sessile à deux liquides est utilisée, on considère en général qu'il n'y a pas adsorption des ions de cette goutte et que la goutte déplace complètement l'alcane qui sert de deuxième liquide: on est alors en présence d’un PZC. Au contraire, dans les mesures de potentiel d'écoulement (streaming potential), la solution joue un rôle important et c'est un IEPS que l'on mesure. Enfin, la charge nette se définit grâce au pH de la solution aqueuse dans laquelle la surface métallique existe, dans un état électriquement neutre (c’est-à-dire [M-OH2+ surf]=[M-O- surf]) et au PZC. - Si pH < PZC alors la charge nette est positive - Si pH > PZC alors la charge nette est négative. Il existe plusieurs méthodes expérimentales permettant de décrire l’état acido-basique de la surface : la mesure du potentiel d’écoulement, la photoélectrochimie, la mesure de l’angle de contact, et la spectroscopie XPS. Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Most of the reported bating technologies for wet blue are based on the usage of acidic protease, which takes a long time and needs large enzyme dosage. A thorough understanding of the basic characteristics of typical acidic proteases and the interaction between enzyme proteins and wet blue fibers will help to improve bating technology for wet blue by selecting the suitable proteases. In this paper, the enzymatic characteristics, molecular weight (Mr) and isoelectric point (pI) of several proteases and their bating effectiveness were investigated. The results indicated that there are two main factors which may affect the wet blue bating effectiveness of acidic proteases. First, the common acidic proteases exhibited low activity towards chrome-tanned collagen fiber which lead to inefficient bating effect through normal dosage. Nonetheless, when the dosages of chrome-tanned collagen fiber activity reached up to 50 U/mL, these acidic proteases also can achieve a good bating effect, the caseinolytic activity has been reached up to 1000 U/mL-4000 U/mL. Second, because of the large molecular weight and the charge repulsion between enzyme proteins and wet blue fibers, the enzymatic hydrolysis process, the penetration and distribution of acidic protease proteins, into wet blue is very difficult. Additionally, neutral proteases have more prospects in wet blue bating process due to the higher chrome-tanned collagen fiber activity and less charge repulsion than acidic proteases. Note de contenu : - MATERIALS AND METHODS : Materials - Thermal stability of proteases - Assay of proteolytic activity on casein substrate - Assay of proteolytic activity on chrome tanned collagen fiber substrate - Determination the molecular weight and isoelectric point of acidic proteases - Bating wet blue with typical protease preparations - Determination of the concentration of soluble protein in the reaction liquor - Determination of the concentration of hypro in the reaction liquor - Histological analysis of collagen fiber - Test of softness and physical properties of crust leather - Characteristics of typical proteases - Effects of activities of acidic proteases on wet blue bating - Comparison of the bating effectiveness of acidic and neutral proteases - Table 1 : Selected wet blue bating protease preparations - Table 2 : Enzymatic characteristics of proteases - Table 3 : Amounts of proteases, soluble protein and hydroxyproline in wet blue bating liquor treated by same dosage of caseinolytic activity - Table 4 : Softness and physical properties of crust leather treated by same dosage of caseinolytic activity - Table 5 : Amounts of proteases, soluble protein and hydroxyproline in wet blue bating liquor treated by same dosage of chrome-tanned collagen fiber activity - Table 6 : Softness and physical properties of crust leather treated by same dosages of chrome-tanned collagen fiber activity - Table 7 : Amounts of proteases, soluble protein and hydroxyproline in wet blue bating liquor - Table 8 : Softness and physical properties of crust leather - Fig. 1 : Thermal stability of proteases - Fig. 2 : SDS-PAGE and IEF-PAGE electrophoresis diagrams of acidic proteases - Fig. 3 : Staining results of collagen fiber in wet blue treated by same dosage of caseinolytic activity - Fig. 4 : Staining results of collagen fiber in wet blue treated by same dosage of chrome-tanned collagen fiber activity - Fig. 5 : Staining results of collagen fiber in wet blue treated by acidic (YNU-A) or neutral (EW01) protease DOI : https://doi.org/10.34314/jalca.v115i12.4202 En ligne : https://drive.google.com/file/d/1a1xhfXBA5gEOf7Ziz0T3ZgVFUWgOzY2u/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34997 [article]

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Development of sustainable strategies for leather waste management through bacterial remediation / A. Sindhuja in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 12 (12/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 12 (12/2020) . - p. 454-458 Titre : Development of sustainable strategies for leather waste management through bacterial remediation Type de document : texte imprimé Auteurs : A. Sindhuja, Auteur ; C. Kurinjimalar, Auteur ; Gladstone Christopher Jayakumar, Auteur ; Arjunan Yasothai, Auteur ; Swarna Vinodh Kanth, Auteur Année de publication : 2020 Article en page(s) : p. 454-458 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries Biodégradation Caractérisation Cuir -- Déchets Cuirs et peaux -- Détérioration Enzymes microbiennes Hydroxyproline Peptidases Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A new Bacillus species has been isolated and used for treating chrome leather wastes. The activity of Bacillus species is evaluated for the degradability of the Chrome Leather Waste (CLW). An initial CLW substrate concentration at 0.5 and 1%, along with the bacterial strain is studied against the control sample without bacterial strain. The higher proteolytic enzyme production and hydroxyproline release in the CLW containing medium confirms the degradation process, whereas it is significantly less in control samples. The degradation profile of CLW shows higher in 1% CLW as compared to 0.5% CLW. In 1% CLW, the protease activity of the isolated strain has been increased from 1.615 to 5.625 U/mL. In addition to protease activity, the isolated strain also expressed chromate reductase activity. Furthermore, FTIR, TGA, and SEM studies confirm the degradation of leather wastes. Note de contenu : - EXPERIMENTAL : Characterization of bacterial species - Evaluation of bacterial strain on chrome leather wases - ATR-FTIR of the chrome shavings - TGA of the chrome shavings - Microscope evaluation - Results and discussion - Fig. 1 : Phylogenetic tree of strain MG995009 - Fig. 2 : FT-IR spectra for treated and untreated samples, magnified image of chances in wave numbers of treated and untreated samples - Fig. 3 : Thermogravimetric analysis of treated and untreated CLW - Fig. 4 : SEM images of treated and untreated CLW of control and 0,5% - Table 1 : Release of protease during the degradation process of CLW - Table 2 : Release of hydroxyproline during the degradation process of CLW DOI : https://doi.org/10.34314/jalca.v115i12.4204 En ligne : https://drive.google.com/file/d/1ZyKTaiUdWrV-bpvWHu6TqCKAsLXwDUbR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34998 [article]

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Thermal sensitive agents for making stimuli responsive leathers / Jaya Prakash Alla in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 12 (12/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 12 (12/2020) . - p. 459-469 Titre : Thermal sensitive agents for making stimuli responsive leathers Type de document : texte imprimé Auteurs : Jaya Prakash Alla, Auteur ; Nishad Fathima Nishter, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2020 Article en page(s) : p. 459-469 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse spectrale Caractérisation Colorimétrie Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés physiques Eaux usées -- Analyse Granulométrie Matériaux intelligents Matériaux sensibles aux stimulis Polyacryliques Syntans Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Herein, we report the synthesis and application of a smart polymeric acrylic syntan (synthetic tanning material), which can respond to temperature and pH. Behavior of polymer at different pH (1-10) at room temperature (28°C) was studied. Also interactions with collagen were ascertained in order to understand the polymers’ response towards secondary structures of collagen. Leather made using the experimental syntan demonstrated higher temperature resistance of 3±0.5°C compared to control syntan treated leathers (1±0.5°C) when exposed to heat under artificial simulation. Experimental leathers exhibited better strength and organoleptic properties. These smart leathers find its application in extreme climatic conditions of heat or cold. Note de contenu : - EXPERIMENTAL SECTION : Materials - Preparation of thermoresponsive acrylic syntan - Collagen polymer interaction studies - Characterization of thermoresponsive syntan - Leather processing and syntan application - Scanning Electron Microscopy (SEM) study of polymer treated leathers - Thermal analysis - Physical strength and organoleptic properties of leather - Effluent parameters - RESULTS AND DISCUSSION : Characterization of thermoresponsive syntan - Clouding behaviour of thermoresponsive polymer - Polymer interaction with collagen - Application of syntan in leather making - Infrared thermal imaging of syntan treated leathers - Scanning electron microscopy of leathers - Physical testing of leather - Porosity analysis of leather - Color measurement of leather - Organoleptic properties - Wastewater analysis - Fig. 1 : Particle size distribution of control and experiment (MTP02) - Fig. 2 : Clouding behaviour of polymer at room temperature - Fig. 3 : Fourier transform infrated spectroscopy analysis of collagen and collagen-polymer (CP) samples - Fig. 4 : Circular dichroism spectra for understanding stability of collagen-polymer interactions - Fig. 5 : Digital images of a) control, c) experimenta, infra-red images of b), control d) experimental syntan treated leather - Fig. 6 : Scanning electron microscopy images showing grain surface of a) control, b) experimental leathers at 50X, cross section images of c) control and d) experiment at 150x magnification - Table 1 : Clouding behaviour of the polymer at different pH - Table 2 : Temperature difference exhibited by control and experimental leathers - Table 3 : Physical strength properties of control and experimental syntan treated leather - Table 4 : Color values of control and experimental leathers - Table 5 : Analysis of waste water DOI : https://doi.org/10.34314/jalca.v115i12.4203 En ligne : https://drive.google.com/file/d/1a7TMFMOQXQr-7hriJSccnrihBn-0sjL_/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34999 [article]

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