| Titre : |
Investigation into the controlled drying of sheepskins : II. Effect of drying conditions on various properties of the skins |
| Type de document : |
texte imprimé |
| Auteurs : |
J. R. Yates, Auteur |
| Année de publication : |
1966 |
| Article en page(s) : |
p. 235-256 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| 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)
Centrifugation
Cuirs et peaux -- Séchage
Cuirs et peaux de moutons
Peau -- Histologie
Peaux brutes -- Teneur en eau
|
| Index. décimale : |
675 Technologie du cuir et de la fourrure |
| Résumé : |
The equilibrium water content (e.w.c.) of sheepskins has been estab-lished over a humidity range of 20-90 percent at 20°C., 35°C. and 50°C. Increase of temperature gives a slight decrease in e.w.c. for a given relative humidity. There is a well defined hysteresis effect as indicated by the e.w.c. values obtained in absorption and desorption. There are differences in the e.w.c. values obtained with samples from similar positions on different skins, and even between different sampling positions within a skin, for equilibration under a given set of conditions. Up to 70 percent of the water held in a sheepskin can be removed by centrifugation, indicating that this water is not very tightly bound. Sheepskins were dried in air currents at room temperature at 30°C., 40°C. and 50°C., by freeze drying, vacuum drying at 1°C., and by acetone dehydration. The skins dried by the latter three methods give, after re-soaking, a skin which most closely resembles a green skin, as judged by water uptake and histological appearance. None of the drying methods tested affects the time taken for wool loosening to occur in the "Sweating" process. |
| Note de contenu : |
- MATERIALS
- METHODS : Effect of controlled humidity on the equilibrium water content (E.W.C.) of the skin - Determination of the water expressible from sheepskins by centrifugation - Drying - Histological examination of sheepskins dried in different ways - Effect of method of drying on the rate of "sweating" (wool loosening)
- RESULTS AND DISCUSSION : Effect of drying and equilibrating at conditions of controlled relative humidity - Determination of the expressible water from sheepskins - Histological investigation of skins dried in the various ways - Effect of method of drying on water uptake properties - Effect of method of drying on water uptake
- Table 1 : Equilibrium water contents (% D.W.B.) of sheepskin
- Table 2 : E.W.C. values (% D.W.B.) for P2 and P5 for saturation humidities
- Table 3 : E.W.C. values for P1-P5 on a particular skin
- Table 4 : Range and mean of E.W.C. values for skin samples
- Table 5 : E.W.C. values after repeated re-equilibrium in the conditioning chamber at 100°F
- Table 6 : Analysis of variance and treatment means for the thickness treatment means for the thickness measurements on the skin after soaking
- Table 7 : Drying X temperature interaction means for water uptake (MG) per standard sample
- Table 8 : Drying X treatment interaction means for water uptake (MG) per standard sample over the complete uptake period 0-3 days
- Table 9 : Drying X solutioninteractionmeans for water uptake (MG) per standard sample
- Table 10 : Swelling means for the drying W soaking treatment
- Table 11 : Means for dry thickness for the skin sample (in. X 10-4)
- Table 12 : Analyis of variance and drying X soaking interaction means |
| En ligne : |
https://drive.google.com/file/d/1kxxnpWKQs1P19-ve5-zvMKmbFeHXLrrc/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37942 |
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXI (Année 1966) . - p. 235-256
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Investigation into the controlled drying of sheepskins in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXI (Année 1966)
