Acoustic emission studies for leather using dual sensors / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CV, N° 4 (04/2010)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CV, N° 4 (04/2010) . - p. 109-115 Titre : Acoustic emission studies for leather using dual sensors Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Joseph Lee, Auteur Année de publication : 2010 Article en page(s) : p. 109-115 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Capteurs (technologie) Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés mécaniques Emission acoustique Rigidité (mécanique) Rupture (mécanique) Traction (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Since leather is sold by the square foot, destructive tests lessen the square footage of the material and infringe on the leather manufacturer's total profit. Therefore there is a need for developing an instrument to perform nondestructive testing of the physical properties of leather. In this investigation, experiments were designed to pass leather test samples through a pair of rotational acoustic sensors, thereby enabling the collection of acoustic emission (AE) signals from both the grain and corium and provide a more accurate assessment of the quality of leather. Observations showed a strong correlation between the mechanical properties of leather and the corresponding cumulative acoustic energy. We also used this dynamic method to characterize the grain break of leather. Results showed that the difference in grain break could be determined form the amount of acoustic hits collected from moving the AE sensors over a leather sample. Observations showed the poorer the grain break ; the more AE energy was detected. Data also demonstrated that thicker samples tended to have poorer grain break. In short, this study demonstrated that the tensile strength, stiffness, toughness ans grain break could be nondestructively determined by measuring acoustic quantities with a pair of rotational sensors. Note de contenu : - EXPERIMENTAL : Materials - AE methods and apparatus - Tensile property measurements - RESULTS AND DISCUSSION : Correlation between AE quantities and physical properties - Leather stiffness - AE evaluation of break En ligne : https://drive.google.com/file/d/1wnXpDZQhYpMFyJR0RdXJp95cXy-G6hX1/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9075 [article]

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Drying leather with vacuum and toggling sequentially / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 3 (03/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 3 (03/2011) . - p. 76-82 Titre : Drying leather with vacuum and toggling sequentially Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Joseph Lee, Auteur Année de publication : 2011 Article en page(s) : p. 76-82 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuir -- Séchage Séchage sous vide Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : We investigated a drying method that will enable leather to be dried under vacuum and stretch sequentially to improve area yield. Vacuum drying offers fast speed at a low temperature, which would be advantageous to heat-vulnerable chrome-free leather. Adding a toggle action after vacuum drying could significantly increase area yield. Using a statistical experimental design, we formulated regression models describing how drying variables affect mechanical properties and area yield of chrome-free leather tanned with glutaraldehyde. An effort was also made to estimate the effects of conditioning, staking, and drum milling on the area retention gained by toggle stretching. This study showed that the direction the stretch was applied had a significant effect on the area retention. Results also indicated that conditioning and staking have little effect on area retention, whereas the drum milling caused a significant drop in area retention. Our study also showed under an optimal drying condition, a 12% increase in area yield with good properties can be achieved. Note de contenu : - EXPERIMENTAL : Materials and procedures - Apparatus - Measurements - experimental design. - RESULTS AND DISCUSSION : Area retention - Effects of staking and drum milling - Tensile strength - Elongation - Fracture energy-toughness - Grain break. En ligne : https://drive.google.com/file/d/12Suk1mD0EZVPw2EtKDWDKV_JAi7F4UZu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11236 [article]

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A drying study for glutaraldehyde-tanned leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 1 (01/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 1 (01/2005) . - p. 8-15 Titre : A drying study for glutaraldehyde-tanned leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Joseph Lee, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2005 Article en page(s) : p. 8-15 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The environmental and health concerns over the use and disposal of chrome-tanned leather have encouraged the use of non-chrome-tanned (chrome-free) leather. The drying operation is a critical leather-making step to attainthe required physical properties for leather products. We recently conducted a drying study on non-chrome-tanned leather made with a glutaraldehyde-tanning process. Results showed that the physical properties of leather, such as area retention and softness, were affected significantly by the drying method. Data revealed that leather with inferior fracture energy often resulted in poor grainbreak. In addition, observations showed that drying methods using toggling produced higher areayield; however, it resulted in stiffer leather. Our research showed that residual water content plays an important role in controlling the softness of leather. Vacuum drying without toggling yields better toughness and softness. A dimensionless quantity "toughness index" showed a strong correlation with the resultant area retention, which agrees with our previous findings for chrome-tanned leather. En ligne : https://drive.google.com/file/d/1ZEAeRJ2nsZu84oaN6E5UKRBy3U1mcj8v/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4085 [article]

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Effects of drying methods on chrome-tanned leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 5 (05/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 5 (05/2004) . - p. 205-210 Titre : Effects of drying methods on chrome-tanned leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Joseph Lee, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2004 Article en page(s) : p. 205-210 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The drying operation is a critical leather-making step to attain the required physical properties for leather products. There are various drying methods currently being used today in leather manufacturing. To make qualityleather, it is imperative to understand the effects of different drying methods on the physical characteristics of leather. Results from our comparison study showed that the method applied in a drying operation significantly affects the physical properties of leather, particularly area retention and compliance. Observations indicated that toggle drying produces higher area yield, but may result in stiffer leather. One of the important findings from this study is that there is a direct link between grain break and stiffness of leather. Data indicated that stiffer leather often results in poor break. Our research again showed that residual water content is a key factor for softness. Vacuum drying without toggling yields better toughness and softness, but does not significantly improve area yield. We also presented a dimensionless quantity "toughness index" that showed a strong correlation with the resultant area retention and stiffness of leather. Toughness index is independent of the geometry of the leather samples. Therefore, even without knowing the thickness or shape of the samples, one can still make an effective comparison of properties. En ligne : https://drive.google.com/file/d/1EEJP60KggcBGB4Srvs8_i1uxHMx7C8pZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4194 [article]

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Glutaraldehyde-tanned leather treated with tocopherol / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 3 (03/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 3 (03/2005) . - p. 102-110 Titre : Glutaraldehyde-tanned leather treated with tocopherol Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Joseph Lee, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2005 Article en page(s) : p. 102-110 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Non-chrome-tanned (chrome-free) leather has gradually gained commercial importance, particularly for automobile upholstery applications. UV and heat resistance are very important qualities for automobile applications. We developed an environmentally friendly finishing process that will improve the UV- and heat resistance of automobile upholstery leather. Tocopherol (Vitamin E) is a potent free radical scavenger and highly protective agent for collagen fibers against UV damage. We previously reported that the application of tocopherol to the grain layer of chrome-tanned leather improved its durability. The current study focuses on non-chrome-tanned leather made with a glutaraldehyde tanning process. We applied tocopherol to the grain layer of that leather and also studied the addition of tocopherol to the fatliquoring drums. Following exposure in a Fade-Ometer, the treated samples were evaluated by colorimetry and mechanical testing for the efficacy of UV- and heat resistance. A polarizing microscope equipped with a Berek compensator was employed to determine the birefringence of the untreated and treated leather collagen fibers to determine the treatment effects on the degree of orientation. Data showed that leather coated with tocopherol exhibited significant improvement in tensile strength retention and color fading resistance against UV radiation and heat. Leather fatliquored with tocopherol, however, did not show a similar improvement. En ligne : https://drive.google.com/file/d/1Dqep6eR5_6KlwhNgqN6P1khbKZPqGh8S/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4073 [article]

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Microscopic observations of leather looseness and its effects on mechanical properties / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 7 (07/2009)  

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Treatment of low-quality hides with fillers produced from sustainable resources : effect on properties of leather / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 10 (10/2009)  

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