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Reflections on research / A. W. Landmann in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 47-48 Titre : Reflections on research Type de document : texte imprimé Auteurs : A. W. Landmann, Auteur Année de publication : 2003 Article en page(s) : p. 47-48 Langues : Anglais (eng) Catégories : Recherche Recherche industrielle Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Research includes development and is the activity which generates new ideas which are to the benefit either the individual organisation or the industry as a whole. There is a cost and it is important that the activity is carried out to achieve the maximum benefit from the expenditure of time and effort. An essential requisite is to establish the objective of the exercise and to ensure that there are testable criteria by which success or failure can be established. Note de contenu : - The problem - The objectives - Testables objectives - The experimental plan En ligne : https://drive.google.com/file/d/1b6uLQ0DhNvcEkf1px8XTyXA-ywSkw7GD/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39798 [article]

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Porosity measurement as a means of determining the degree of determining the degree of processing of lamb pelt / T. F. Allsop in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 49-54 Titre : Porosity measurement as a means of determining the degree of determining the degree of processing of lamb pelt Type de document : texte imprimé Auteurs : T. F. Allsop, Auteur ; A. Passman, Auteur Année de publication : 2003 Article en page(s) : p. 49-54 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux d'agneaux Mesure Porosité Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Removal of non-collagenous skin substances during the early stages of lambskin processing can be monitored by measuring the increasing porosity of the pelts. An experimental technique has been developed to measure skin porosity as a function of the maximum pressure required to drive air through the pelt from the flesh to the grain surface using a simple apparatus. Readings should be taken at the OSP of skins directly from processing. The technique can be used to monitor the progress of enzyme processing or the effects of different levels of application of enzyme treatments. Note de contenu : - MATERIALS AND METHODS : - Apparatus and technique for measuring skin porosity - Intrinsic variability in skin porosity - Processing effects on skin porosity - RESULTS : - Measurement conditions - Within and between skin variability in porosity - Effect of process stage on porosity - Effect of duration of bating on porosity - Effect of concentration of bate on porosity - Table 1 : Variation in porosity pressure at various locations on lambskins - Table 2 : The effect of processing stage on the porosity of lamb pelts En ligne : https://drive.google.com/file/d/1wWwqSEwmFBIOH9VZW8En1FoK7LPe8Kn3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39799 [article]

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Modifying products of enzymatic breakdown of chrome-tanned leather wastes with glutaraldehyde / F. Langmaier in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 55-61 Titre : Modifying products of enzymatic breakdown of chrome-tanned leather wastes with glutaraldehyde Type de document : texte imprimé Auteurs : F. Langmaier, Auteur ; Karel Kolomaznik, Auteur ; Milan Mladek, Auteur Année de publication : 2003 Article en page(s) : p. 55-61 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) Colloides Cuir -- Déchets Glutaraldéhyde Hydrolysat de collagène Matériaux -- Modifications chimiques Tannage au chrome Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Hydrolysates of chrome-tanned leather waste from tanning manufacture react with glutaraldehyde to produce thermo-reversible or thermo-irreversible gels. The rigidity of the thermo-reversible gels is limited to values around 100g-1 (o Bloom) (as determined by the standard procedure). The conditions for the formation of such gels were optimised. Gels attaining higher rigidity lose the property of thermo-reversibility, however they continue to swell infinitely in water even though their swelling is slower. Thermo-reversible gels can be employed as glues, thermo-irreversible gels are applicable in currently widespread encapsulation techniques. Expanding the possibilities for industrial applications of such products may improve the economic balance of disposal of solid chrome-tanned leather wastes from tanning in an environmentally feasible manner, which is a serious problem when introducing “clean” leather-manufacturing technology into current practice. Note de contenu : - Starting Material - UV spectrophotometry of the reaction of collagen hydrolysate with glutaraldehyde - Formation of gels in reaction of hydolysate with glutaraldehyde - Table 1 : Characteristics of of chrome-tanned leather waste hydrolysate - Table 2 : Time dependence of extinction at wavelengths λ = 265, 300 and 325 nm in reaction of collagen hydrolysate solution with glutaraldehyde - Table 3 : Factorial experiment 23 for studying suitability of extinction measurements in UV region for observing reaction course of chrome-tanned waste hydrolysate with glutaraldehyde - Table 4 : Analysis of variance of factorial experiment from Table III - Table 5 : Scheme of factorial experiment: Influence of reaction conditions on characteristics of collagen hydrolysate with glutaraldehyde - Table 6 : Scheme of factorial experiment : Influence of reaction conditions on characteristics of formed through reaction of collagen hydrolysate with glutaraldehyde - Table 7 : Analysis of variance in factorial test 23 from Table VI En ligne : https://drive.google.com/file/d/1EVHTT1lqBTilFh9DpFfDk5ELgQ8atDtU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39800 [article]

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Influence of a synthesized condensed polymer as a pre and retanning agent on the properties of buffalo leather / El-Shahat H. A. Nashy in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 62-68 Titre : Influence of a synthesized condensed polymer as a pre and retanning agent on the properties of buffalo leather Type de document : texte imprimé Auteurs : El-Shahat H. A. Nashy, Auteur Année de publication : 2003 Article en page(s) : p. 62-68 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents de tannage Caractérisation Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux de buffles Polymères -- Synthèse Prétannage Retannage Tannage synthétique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Asynthetic sulphited polymer based on a urea - paraformaldehyde condensate has been prepared to be used as pre and retanning agent. The influence of the prepared polymer on buffalo leather was investigated and compared with the most commonly applied products, chrome tan with vegetable extract retannage. The properties of the treated leather, namely tensile strength, elongation at break, tear strength, deformability, scanning electron microscope examination, thermal stability and appearance were studied. These parameters were used to evaluate the polymer’s applicability as an efficient environment friendly tanning agent. Note de contenu : - MATERIALS AND METHODS - RESULTS AND DISCUSSION : - A - Polymer synthesis - B - Characterization of the treated leather - Table 1 : Strength properties - Effect of different tanning agents and procedures - Table 2 : TGA for buffalo tanned leather by Chrome process and polymer with chrome - Table 3 : Visual and handle evaluation of buffalo tanned leather - Table 4 : Physico-chemical valuation of the leather produced by the two processes En ligne : https://drive.google.com/file/d/1GKgRW7UGr6a4cGSzGjTMZLHdip6fmWIe/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39801 [article]

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Hair saving unhairing process. Part 5 characterisation of enzymatic preparations applied in soaking and unhairing processes / Carlos S. Cantera in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 69-77 Titre : Hair saving unhairing process. Part 5 characterisation of enzymatic preparations applied in soaking and unhairing processes Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; L. Goya, Auteur ; Betina Galarza, Auteur ; Maria Laura Garro, Auteur ; Laura M. I. Lopez, Auteur Année de publication : 2003 Article en page(s) : p. 69-77 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Epilage enzymatique Peaux brutes -- Trempe Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Considering the importance that is attached to the characterisation of proteolytic enzymatic preparations employed in leather making, especially in the development of enzyme unhairing, our studies are aimed to develop a protocol of analysis that allows us to determine the behaviour of the enzymes on diverse protein skin substrates. In the protocol presented here it is important to highlight the incorporation of the so-called ‘epidermis substrate’, comprising the epidermis layer, hair and the root sheaths, as well as the procedure to assess enzymatic action on the proteoglycans. On two of the substrates, “epidermis” and Hide Powder Azure, studies on activation/inhibition of the enzyme activity using components usually added in the soaking and unhairing processes was also carried out. The protocol was applied to two commercial enzymatic preparations commonly used in leather processing, and to an extract of vegetable proteases that CITEC, jointly with LIPROVE, is applying in its investigation on enzyme unhairing. The protocol developed is a useful tool to assist us in the design of ideal enzyme unhairing: that in which the enzymatic activity is orientated towards the components of the epidermis system, when their action on fibrous proteins – particularly collagen - is minimised or avoided and when the leathers developed have the desired properties. Note de contenu : - INTRODUCTION : Chromogenic substrates - The epidermis layer, hair and root sheaths : the ‘epidermis substrate’ - Activity on proteoglycans (PGs) and hide powder substrate - OBJECTIVES - MATERIALS AND METHODS : 1) Assessment of protein content - 2) Assessment of activities on different substrates : Non – keratin based substrates - Activity upon proteoglycans (PGs). Hide powder substrate - Keratin-based substrates - 3) Inhibition and activation tests - 4) Protein Profile. Electrophoresis in SDS/polyacrylamide gel (PAGE) - 5) Isoelectric Focusing (IEF) - Zymogram - EXPERIMENTAL RESULTS - PROTEOLYTIC ACTIVITY AGAINST DIFFERENT SUBSTRATES AND ACTIVATION AND INHIBITION ASSAYS - ANALYSIS OF THE RESULTS : Activation and Inhibition Tests - Table 1 : Proteolytic activity of the enzymatic preparations against different substrates - Table 2 : Ranges of pH corresponding to 90% of the maximum activity for each one of the enzymatic preparations (maximum activity pH value is shown in brackets) - Table 3 : Changes in the activity of Alcamax and Pellvit against the chromogenic substrates hide powder azure and ‘epidermis’ adding components used in soaking and unhairing processes (*) En ligne : https://drive.google.com/file/d/1lrLmDHNIHN7pji0LbISFfwO_LGJtTNU1/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39802 [article]

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Stimulation of the chrome tannage process by vacuum / V. Tricys in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 78-81 Titre : Stimulation of the chrome tannage process by vacuum Type de document : texte imprimé Auteurs : V. Tricys, Auteur ; Kestutis Beleska, Auteur ; Virgilijus Valeika, Auteur Année de publication : 2003 Article en page(s) : p. 78-81 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Tannage au chrome Tannage sous vide Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This paper presents the results of an investigation into the promotion of leather manufacturing by vacuum. The chromium tannage process was chosen as a model and influence of the factors such as thickness of pelt, temperature, concentration of Cr2O3 in the chroming solution and additionally, the use of pressure on the rate of solution penetration and qualitative indexes of leather was investigated. It was established that the use of 0.01 MPa vacuum reduces the duration of chroming to 3-20 minutes depending on the pelt thickness. An increase of temperature does not noticeably shorten the time of chroming but it has a positive influence on the shrinkage temperature of the leather. An increase in concentration of the chromium compounds in the chroming solution does not result in a large increase of amount of Cr2O3 in the leather. Comparing the acceleration of the process by either pressure or vacuum proved the use of vacuum to be more effective than the use of pressure. Note de contenu : - Influence of pressure difference on duration of chromium tannage - Influence of pelt thickness on duration of the chromium tannage - Influence of temperature on the chroming process - Table 1 : Chrome content and shrinkage temperature of samples after chroming 'with solution' A – penetration through flesh side first ; B – through grain side first En ligne : https://drive.google.com/file/d/18H12t5EvsVbsQweaCvbmIWY_JNG0dTuk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39803 [article]

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