Leather and Footwear Journal

Volume 14, no 2

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Evaluation of Sheepskin Sitting Pad in Pressure Relieving
- Pages 75-84
  Jin ZHOU^1,2, Bo XU¹, Carmen GAIDĂU³, Wuyong CHEN¹*
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University Chengdu 610065, P. R. China, email: zj_scu@qq.com, wuyong.chen@163.com
  - ²Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, Sichuan University, Chengdu 610065, P. R. China
  - ³INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, Bucharest 031215, Romania
  ABSTRACT. This study aimed at quantitatively evaluating the effectiveness of sheepskin sitting pad (SSP) in pressure relief in the wheelchair. Eighteen students were recruited from the university and those subjects with Body Mass Index (BMI) over 24.5 and with a history of back pain were excluded. Participants were guided to sit in a wheelchair, where contact pressure with and without SSP was measured by sitting pad pressure measurement. Four masks model was developed (total region, left, right and central buttock) and under each region peak pressure (mmHg) (PP), mean pressure (MP) and contact area (cm2) (CA) were calculated. Wilcoxon Signed Ranks and reliability analysis were used for statistical analysis with a significant level of 0.05. Our results show that, with the assistance of SSP, CA at each area was improved, but those findings were not significantly recorded; further, mean MP was significantly reduced by 15.8 mmHg and the decrease of PP was less significant than that of MP. Most of our outcomes were approved to be reliable and repeatable. Overall, sheepskin sitting pad could significantly increase the contact area and reduce the intensity of pressure concentration; further, most of our outcomes were reliable and repeatable. Hence, sheepskin sitting pad is a useful pressure relieving product.
  
  KEY WORDS: contact pressure; sheepskin sitting pad; ulcer prevention; pressure ulceration
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A Finite Element Analysis Study of Footwear Lower Ensemble Influence on the Plantar Pressure Distribution
- Pages 85-92
  Răzvan MOCANU*, Ioan CIOARĂ
  - Gheorghe Asachi Technical University of Iasi, Faculty of Textiles & Leather Engineering and Industrial Management, email: razvan_mocanu@yahoo.com
  ABSTRACT. The plantar pressure distribution has a complex influence on the kinetics and kinematics of the lower limbs. The foot bedoutsole ensemble must provide the correct support of the foot and add corrections if necessary, in order to adjust the pressure distribution on the foot plantar surface. A poorly designed outsole, a feeble midsole or the incorrect care and use of the footwear product will lead to the deterioration of the foot bed functionality. The degree of the foot bed deterioration can be determined using in-shoe plantar pressure measuring devices. This loss of functionality must be prevented as much as possible in the design stage. Footwear prototyping and wearing tests are very expensive and time consuming and do not represent a viable method in economic terms. The fastest and less expensive testing method suitable for footwear production in design stages is the Finite Element Analysis. To use this method we developed a 3D CAD model of the human foot using as model a real 3D scanned foot. The scanned foot was processed in various 3D CAD systems in order to obtain a FEA usable 3D part. The developed model was used to determine how the ensemble of a specific sole design and a midsole with wear characteristics modify the plantar pressure distribution.
  
  KEY WORDS: footwear, outsole, CAD, FEA
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Evaluation of the Relationship between Bacterial Population and Associated Gas Generation in Soaking Float of Sheep Skin Using a Sensor Array System
- Pages 93-106
  Ünal KIZIL¹, Ali Nail YAPICI²*, Binnur Meriçli YAPICI³, Sadi Turgut BILGI⁴, Melis INALPULAT¹
  - ¹Agricultural Sensor and Remote Sensing Laboratory, Faculty of Agriculture, Department of Agricultural Structures and Irrigation, Çanakkale Onsekiz Mart University, 17020, Çanakkale/Turkey, e-mail: unal@comu.edu.tr, melissacan@comu.edu.tr
  - ²Department of Textile, Clothing, Shoes, and Leather, Çanakkale Vocational School of Technical Sciences, Çanakkale Onsekiz Mart University, 17020, Çanakkale/Turkey, e-mail: yapicin@comu.edu.tr
  - ³Department of Biology, Faculty of Arts and Sciences, Çanakkale Onsekiz Mart University, 17020, Çanakkale/Turkey, e-mail: byapici@comu.edu.tr
  - ⁴Department of Midwifery, School of Health, Canakkale Onsekiz Mart University, 17020, Çanakkale/Turkey, e-mail: stbilgi@comu.edu.tr
  ABSTRACT. In this study it was aimed to design a metal oxide gas sensor array to determine the bacterial load in soaking float of wet-salted domestic sheep skin for garment leather production. The results showed that an array of 4 metal oxide gas sensors employed with Artificial Neural Networks (ANNs) can predict the bacterial population in soaking float of leather manufacturing. The relationship between predicted and observed bacterial populations yielded a R2 value of 0.95 in model testing. Design procedures, gas sensors and other materials and techniques were explained in this paper.
  
  KEY WORDS: leather, bacteria, gas sensors, odor, artificial neural networks
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Comparative Study Regarding the Resistance of Wet-White and Wet-Blue Leather to the Growth of Fungi
- Pages 107-120
  Corina CHIRILĂ*, Viorica DESELNICU, Marian CRUDU
  - INCDTP - Division: Leather and Footwear Research Institute Bucharest, 93 Ion Minulescu st., sector 3, RO-031215 Bucharest, e-mail: corina.chirila@icpi.ro
  ABSTRACT. Both tanned and finished leather may be damaged by fungi from Aspergillus flavus and Aspergillus niger, Trichoderma viride, Penicillium glaucom and Penicillium cyclopium, and Paecilomyces variotii species which irreversibly damage leather through the enzymes (collagenases, lipases and proteases) they produce. Fungi grow quickly under high humidity conditions and temperatures ranging between 25 and 30°C. This paper presents a comparative study regarding the fungal resistance of wet-blue (chromium-tanned) leather, wet-white leather tanned with titanium-aluminium-based compounds and wet-white leather tanned with resorcinol-oxazolidine. The study was performed according to ASTM Standard D 4576 - 08(2013) - Test Method for Mold Growth Resistance of Wet Blue. Conclusions of this study about mould growth resistance are drawn from the results obtained for a period of 28 days. It has been concluded by this study that no leather type is completely resistant to fungal attack. Wet-blue leather is highly susceptible to fungal attack of Aspergillus niger and Aspergillus flavus; Trichoderma viride and Mucor pusillus species do not grow on chromium-tanned wet-blue leather. Wet-white leather tanned with Ti-Al is attacked by all types of fungi studied. Wet-white leather tanned with resorcinol-oxazolidine is attacked by Aspergillus niger and Mucor pusillus, but inhibit the growth of moulds from the Aspergillus oryzae and Trichoderma viride species. This type of leather may also be damaged by moulds from the Penicillium genus.
  
  KEY WORDS: wet blue, wet white, fungi resistance
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