Leather and Footwear Journal

Volume 18, no 4

Contents
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On the relationship between foot pressure distribution and sole hardness during long-time standing
- Pages 249-258
  Xintao XIE
  - Physical Education College of Xi'an Technological University, Xi'an 710032, China, xxtyy2004@163.com
  ABSTRACT. For people like soldiers, doctors and traffic police who need to stand for a very long time at work, their feet are under long-time pressure; thus, their foot health affects their work and life. Based on the foot pressure sensing system Footscan. This paper studies the foot pressure distribution during long-time standing. According to the subjects' subjective assessment and experimental results, the author carries out statistical analysis on how different sole hardness can relieve the foot pressure during long-time standing. The conclusions are of great guiding significance to help people who need to stand for a long time at work scientifically relieve their foot pressure and select suitable footwear.
  
  KEY WORDS: long-time standing, Footscan, sole hardness, subjective assessment, experiment
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High bloom gelatin strength from white leather shavings
- Pages 259-274
  Hamed M. ELSAYED^1*, Rasha Z. ATTIA¹, Ola A. MOHAMED¹, Nabil H. EL-SAYED¹, Saber A. IBRAHIM^2*
  - ¹Chemistry of Tanning Materials and Leather Technology Department, National Research Centre, Dokki, Cairo 12622, Egypt
  - ²Packaging Materials Department, National Research Centre, Dokki, Cairo 12622, Egypt
  ABSTRACT. Leather making process is recognized as one of the highly polluting extensive industries which generate huge amounts of solids and liquid tannery wastes. These wastes effect in severely way on the surrounding environment and human health if these polluting not well treated. The aim of this article is to obtain high bloom gelatin from white leather shavings (untanned hide shavings, WLS) via alkaline hydrolysis for improved utilization of leather waste. This research introduces a system of reusing technologies for WLS wastes including preparing gelatin, isolating collagen protein by extracting method then characterization of extracted gelatin. This article recognized to determine efficiency of the thermal and chemical treatments on the white leather waste in recovering the largest amount of gelatin with high bloom strength and a smallest amount of residue. Chemical treatments of white solid wastes by partial hydrolysis of wastes using different factors affecting on hydrolysis such as alkalis concentration, temperature and contact time were discussed. The method verified that the leather wastes can be successfully processed to the powder like leather gelatin products. It was found that the optimum conditions to obtain high bloom gelatin strength from white shaving leather wastes around 150 bloom are 4 % w/v NaOH, 4 hours contact time, 250 rpm at 500°C.
  
  KEY WORDS: alkaline hydrolysis, gelatin, high bloom strength, SEM, white leather shavings
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The effect of backpack load on motion coordination of school children
- Pages 275-282
  Nan ZHOU^1,2, Wuyong CHEN^1*, Jin ZHOU¹, Luming YANG¹
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu, 610065, China
  - ²Guangzhou Shiling Leather & leather products investigation center, No.6 Yangguang Road Shiling Town, Huadu district, Guangzhou city, Guangdong province, 510850, China
  ABSTRACT. The aim of this study was to explore the influence of the load of a backpack on the coordination of motion of healthy children aged 7 to 12. 100 healthy schoolchildren were recruited and they were quantified with the normal BMI, no foot deformities or injuries, no abnormal gait patterns. Coda Motion System was used to record the angle of walking with backpack loads of 0%, 5%, 10%, 15%, 20% and 25% of their body weight (BW) randomly. Vector angles between angle of head, body, knee and ankle were first calculated and then the phase angle (PA) and continuous relative phase (CRP) including their standard deviations (SD) were figured out. Distinctions within six load condition were evaluated by covariance univariance with significance level of 0.05 and a confidence interval of 95%. Our results show that significant effect loading on the CRP of head and body was found (p=0.005<0.01), where 0%BW (p=0.002<0.05), 5%BW (p=0.001<0.05) and 10%BW (p=0.008<0.05) were recorded with smaller CRP values than those of 20%BW. However, no significant distinctions were found between 20%BW and 25%BW. Although significant differences were not found for all PA variables, their decreased simultaneously with the weight of backpack increasing, particularly in the body and ankle. Overall, coordination in motion of schoolchildren was partially influenced by an increasing load of the backpack, as significant body tilt was performed by the children to overcome the backwards drag, while other body parts were not affected.
  
  KEY WORDS: backpack loading, continuous relative phase, phase angle, coordination of motion
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Effect of crusting operations on the mechanical properties of leather
- Pages 283-294
  Kallen Mulilo NALYANYA¹, Ronald K. ROP¹, Arthur ONYUKA², Zephania BIRECH³, Alvin SASIA²
  - ¹Department of Physics, Faculty of Science, Egerton University, Nakuru, Kenya, kallenmulilo@ymail.com
  - ²Kenya Industrial Research and Development Institute, Nairobi, Kenya
  - ³Department of Physics, School of Biological and Physical Sciences, University of Nairobi, Kenya
  ABSTRACT. Physical properties of leather form vital quality parameters that determine the performance characteristics in their areas of applications. However, the transformational processing of hide to leather involves a series of both chemical and physical/mechanical changes that affect these mechanical properties. Many researches have been published regarding the effect of processing on the mechanical properties of leather. However, the effect of entire crusting operations (post tanning) on the mechanical properties is not documented. This study reports the findings of the effect of crusting operations (retanning, dyeing and fatliquoring) on the mechanical properties of the final leather. Results have shown that retanning process improves tear and tensile strengths, distensions at crack and burst, and shrinkage temperature. An improvement in the organoleptic properties such as fullness was recorded in retanned crust leather. However, the uniformity coefficient and percentage elongation significantly decreased after retanning. Dyeing raises the elongation at break, distensions at crack and burst, shrinkage temperature and uniformity coefficient whereas both tensile and tear strengths decreased after dyeing. Similarly, fatliquored samples recorded higher elongation at break values, and distension values. Conversely, tensile and tear strengths, shrinkage temperature and uniformity coefficient decreased as a result of fatliquoring process. All the samples tested at tanning, retanning, dyeing and fatliquoring processes indicated no damage at 50,000 flexes. The study discussed these effects using transmission of fracture and damage mechanics in leather, structural implication of the resulting leather and existing models of materials.
  
  KEY WORDS: physical properties, crusting operations, leather anisotropy and uniformity, fracture and damage mechanics, micromechanical deformation, stress concentration
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Integrating anthropometry approach and Kansei engineering in the design of children shoe
- Pages 295-306
  Annisa Dwi NOVIANI, Ari WIDYANTI
  - Department of Industrial Engineering, Bandung Institute of Technology (ITB), Indonesia, Labtek 3 Ganesa 10 Bandung 40132 Indonesia, email: widyanti@mail.ti.itb.ac.id
  ABSTRACT. Shoes play an important role in human life. For children in particular, shoes also support the development of their feet. This study is aimed to integrate anthropometric approach with Kansei Engineering in designing shoes for Indonesian children. Eighteen dimensions of foot anthropometry for 331 Indonesian Sundanese children ages 6-10 were measured and presented, a shoe size chart for Indonesian children is proposed as well. Moreover, Kansei Engineering was applied to capture consumers' 'emotion' toward children's shoe design and was evaluated both for Indonesian parents and children. The result shows that emotion related to children's shoe design are comfort and appearance. The implication of the results is further discussed.
  
  KEY WORDS: Indonesian, children, shoe, anthropometry, Kansei, engineering
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Bindings of rare books from the collections of the Romanian Academy Library - a multidisciplinary study
- Pages 307-320
  Cristina CARSOTE¹, Luminita KOVARI², Carmen ALBU², Emanuel HADIMBU³, Elena BADEA^3,4*, Lucretia MIU³, Gabriela DUMITRESCU²
  - ¹The National History Museum of Romania, 12 Calea Victoriei Street, 030026 Bucharest, Romania
  - ²Department of Manuscripts and Rare Books, Romanian Academy Library, 125 Calea Victoriei Street, 010071 Bucharest, Romania
  - ³INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu Street, 031215 Bucharest, Romania
  - ⁴Department of Chemistry, Faculty of Sciences, University of Craiova, 107 I Calea Bucuresti Street, 200512 Craiova, Romania
  ABSTRACT. This paper presents an overview of the conservation state of the tawed white leather, parchment and reused parchment bookbindings from the Rare Book Collection of the Romanian Academy Library. The transdisciplinary study was jointly conducted by the researchers of INCDTP-ICPI and Manuscripts and Rare Book Department of the Romanian Academy Library. Over 50 bindings in alum-tawed (white) leather, parchment and reused parchment were analyzed in situ using specific non-invasive or micro-invasive analysis methods such as visual and microscopic analyses, thermal microscopy (imageMHT method), attenuated total reflection (ATR), Fourier transform infrared spectroscopy (FTIR), and X-ray Fluorescence Spectrometry (XRF). Based on these results, conservation sheets have been drawn up including damage status, threats and conservation recommendations for each investigated bookbinding. Two conservation sheets are illustrated for alum-tawed and re-used parchment bindings. This is the first Romanian study dedicated both to the artistic and material aspects of rare book bindings so far.
  
  KEY WORDS: bookbinding, alum-tawed leather, parchment, damage status, conservation reccommendations
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Leather as a potential liner for the prosthetic leg users
- Pages 321-326
  Arife Candas ADIGUZEL ZENGIN*, Nilay ORK, Umitcan YIGIT, Behzat Oral BITLISLI
  - Ege University, Engineering Faculty, Leather Engineering Department, 35100, Bornova, Izmir, Turkey, candas.adiguzel@ege.edu.tr
  ABSTRACT. Wear comfort and hygiene is responsible for the significant improvement in the life quality of many amputees and in this regard liners have an important role for the prosthetic leg users. They are protective materials used as covers and worn over the residual limb before the socket to prevent the discomfort occurred during the movements of the patients. Liners are made of different synthetic flexible materials and designed with specific features for different suspension systems. Selecting a correct liner depends on the activity level and needs of the users in addition to the suspension system of the prosthetic leg. Although liners ensure wearing comfort to the users, feeling uncomfortable occurs due to perspiration and lack of evaporation. In this context, leather has advantages due to its triple helix collagen fibers and seems to be a perfect alternative natural material to synthetic liners. For this purpose, the production of a leather liner as an alternative to synthetic liners was aimed to perform for the prosthetic leg users. Chromium free leathers were manufactured based on the properties of the synthetic liners found in the market and the physical, mechanical and comfort properties of the liners in terms of water vapor permeability, static water absorption, tensile strength, elongation at break, tear strength, rubbing fastness and thickness were determined. The results revealed that leather could be used as an alternative natural liner for the use of prosthetic legs and has become prominent due to its wear comfort, hygiene and mechanical properties.
  
  KEY WORDS: leather, prosthesis, liner
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Bio-composites with leather fibers and cement - physicomechanical and structural characterization
- Pages 327-336
  Gabriel ZAINESCU¹, Viorica DESELNICU^1*, Roxana CONSTANTINESCU¹, Claudiu CIULACU²
  - ¹National R&D Institute for Textiles and Leather - Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., 031215, Bucharest, Romania, e-mail: icpi@icpi.ro
  - ²S.C. PROCEMA - Cercetare SRL, 6R Preciziei st., sector 6 Bucharest, Romania, e-mail: office@procema-cercetare.ro
  ABSTRACT. Circular economy systems keep the added value in products for as long as possible and eliminate waste. Resources are kept within the economy when a product has reached the end of its life, so that they can be productively used again and again and hence create further value. In this context, the specialists from leather and footwear sector look for innovative solutions for utilization of leather wastes for obtaining of new bio-composites with application in construction industry. This paper presents utilization of leather wastes for obtaining construction materials for pedestrian walkways (paving blocks) containing leather fibers obtained from leather waste and their physicalmechanical and structural characterization.
  
  KEY WORDS: leather waste, leather fibers, concrete, bio-composite
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