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Auteur Timothy D. Stilwell |
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Assessment of vegetable tannin extracts by colorimetry / Timothy D. Stilwell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 6 (06/2001)
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Titre : Assessment of vegetable tannin extracts by colorimetry Type de document : texte imprimé Auteurs : Timothy D. Stilwell, Auteur ; Bruce W. Buehrig, Auteur ; Robert J. Harvey, Auteur ; L. Shepley Hermann, Auteur ; Jean J. Tancous, Auteur Année de publication : 2001 Article en page(s) : p. 192-204 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Spray-dried, untreated wattle and treated quebracho extracts were tested for color by four laboratories equipped with Lovibond Tintometers. A comparison of color readings was conducted at the U.S.H.S.L.A. Laboratory where more reasonably priced meters, a Jenway Colorimeter and a Milton-Roy Spectrophotometer, were used. Time for testing was shortened considerably because preliminary tannin analyses were not done and the meters were simpler to operate. Samples of extracts were weighed, dissolved in distilled water, heated to 82oC, cooled and read immediately. A ratio, constructed by dividing yellow readings by red readings, was found to be a valuable method for understanding factors that influence color such as pH and addition of reagents. En ligne : https://drive.google.com/file/d/149LW5NP9yrPYRBQMilRHVQ4FIsZpsm8H/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4371
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 6 (06/2001) . - p. 192-204[article]Réservation
Réserver ce documentEvaluation of modifications to the alca standard method for tannin analysis in tannery liquors / Robert J. Harvey in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 4 (04/2003)
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Titre : Evaluation of modifications to the alca standard method for tannin analysis in tannery liquors Type de document : texte imprimé Auteurs : Robert J. Harvey, Auteur ; Bruce W. Buehrig, Auteur ; Timothy D. Stilwell, Auteur ; L. Shepley Hermann, Auteur Année de publication : 2003 Article en page(s) : p. 147-152 Note générale : Biliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The American Leather Chemists Association (ALCA) Standard Method for tannin analysis was developed to provide tanners with a way to monitor the relative strength of tan liquors in their process. Although it took full advantage of existing technology in the early 1900's, that method is very restrictive, laborious and time consuming. Advances in filtering technology allow modern researchers to process materials much more efficiently than in the past. Several filtration methodologies were incorporated into existing ALCA methods, and modifications were evaluated for time efficiency, effectiveness, and comparability to the Standard Methods. Direct determination of solids on undiluted tan liquor was evaluated against the Standard Method procedures. En ligne : https://drive.google.com/file/d/1cvdwHw345S9jYb8pXl0tTH9-JDzA_-Vb/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4117
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 4 (04/2003) . - p. 147-152[article]Réservation
Réserver ce documentPratical evaluation of ethylenediaminetetra-acetic acid for controlling iron stains on vegetable tanned leather / Timothy D. Stilwell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 12 (12/2001)
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Titre : Pratical evaluation of ethylenediaminetetra-acetic acid for controlling iron stains on vegetable tanned leather Type de document : texte imprimé Auteurs : Timothy D. Stilwell, Auteur ; Mark W. Armstrong, Auteur ; Jean J. Tancous, Auteur ; L. Shepley Hermann, Auteur ; W. Buehrig, Auteur Année de publication : 2001 Article en page(s) : p. 481-490 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanners of vegetable tanned leather have observed that when iron contacts moist or wet leather it causes gray to black stains. For years, the chelating agent, ethylenediaminetetraacetic acid (EDTA), has been added to dry tannin extracts and to tanning liquors to prevent iron stains. This study was conducted to find out how much iron is present in tannins and in tan liquors and to find out how much iron, in the absence of EDTA, would be needed to cause iron stains. Analytical analyses and color determinations, using sheepskin skivers and colorimetry, showed that EDTA, an expensive chemical, did not need to be added during tanning and retanning of vegetable tanned leather. En ligne : https://drive.google.com/file/d/1Zchpl1gke9tqq6d_aIsFmVsiVU6Zxp7U/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4347
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 12 (12/2001) . - p. 481-490[article]Réservation
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