Leather and Footwear Journal

Volume 21, no 2

Contents
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LIFE CYCLE ASSESSMENT OF PROCESSING FOR CHROME TANNED COWHIDE UPPER LEATHER
- Pages 75-86
  Heng YANG¹, Dexin AN¹, Carmen GAIDAU², Jinwei ZHANG¹, Jin ZHOU¹*
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P.R. China; 1518449567@qq.com, 1946828368@qq.com, scutanner@163.com, zj_scu@scu.edu.cn
  - ²Leather Research Department, INCDTP – Division: Leather and Footwear Research Institute, Bucharest 031215, Romania; carmen_gaidau@hotmail.com
  ABSTRACT. Pollution has become a serious problem in leather industry, however, current method to evaluate its environmental effect usually used data from literature review, those data generated while leather manufacturing were rarely collected and analyzed. Thereby, the aim of this study was to evaluate the environmental effect of manufacturing process of chrome tanned cowhide upper leather by applying the Life Cycle Assessment protocols. Following the guidance of ISO 14010, we first combined data obtained from field study and empirical review; and then these data were input into eFootprint for calculation. Results, including four environmental indicators (global warming potential [GWP], primary energy demand [PED], water utility [WU] and acidification [AP]), show that producing 1 kg of cowhide upper leather releases 7.040 kg of CO₂ eq, consumes 106.793 MJ of energy and 89.144 kg of water and emits 0.058 kg of SO₂ eq. Sensitivity analysis of inventory data demonstrated that chrome tanning and retanning processes accounted for more than 40% of PED, AP and GWP, whereas the beamhouse was more than 78% of WU. Therefore, we could optimise the tanning process by using alternative materials or technologies in the critical sections to achieve cleaner production and sustainable leather manufacturing.
  
  KEY WORDS: life cycle assessment, leather processing, leather cleaner production, carbon footprint
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BIOMECHANICAL PARAMETERS CHARACTERISING THE FOOT DURING NORMAL GAIT
- Pages 78-104
  Arina SEUL, Aura MIHAI*, Antonela CURTEZA, Mariana COSTEA, Bogdan SÂRGHIE
  - "Gheorghe Asachi" Technical University of Iasi, Doctoral School, Faculty of Industrial Design and Business Management, 28 Mangeron, 700050, Iasi, Romania
  ABSTRACT. The biomechanical analysis allows to understand the normal and pathological gait, the mechanics of neuromuscular control, and last but not least, allows the visualisation of the effects of footwear on human gait or feet. Biomechanical analyses are very important for the footwear development process, as they can identify the incorrect loading of the foot or the incorrect gait pattern, thus avoiding the occurrence of deformations. This paper aims to create an average representative model of barefoot loading based on an extended group of participants by applying an optimal procedure for measuring biomechanical parameters. The variation of four basic biomechanical parameters, namely force, pressure, contact time and contact area, was measured using a pressure platform and a specialised software system. The data was collected from 32 healthy females, without particularities regarding foot health and the practice of performance sports, aged between 18 and 30 years, divided into three size groups – 36, 37 and 38. The T-Student test was applied to verify if there are significant differences between the left and right foot. Statistical indicators for each parameter were calculated, in order to characterize and establish the degree of variation of the obtained values, as follows: mean, standard deviation, minimum and maximum values, the amplitude of variation and coefficient of variation (CV). The study results confirm that the obtained mean values can be used as input data to load the foot and perform virtual simulations of footwear products.
  
  KEY WORDS: foot, biomechanics, normal gait
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ENZYMATIC ACTIVITY OF ALKALINE PROTEASE FROM Bacillus cereus TD5B AND ITS APPLICATION AS SHEEP SKIN DEHAIRING AGENT
- Pages 105-118
  Nanung Agus FITRIYANTO¹, MUSTHOFIYAH¹, MUHLISIN², Ambar PERTIWININGRUM¹, Novita KURNIAWATI¹, Ragil Adi PRASETYO¹, Aldyon Restu AZKARAHMAN¹, Yuny ERWANTO¹
  - ¹Department of Animal Products Technology, Faculty of Animal Science, Universitas Gadjah Mada, Indonesia; nanungagusfitriyanto@ugm.ac.id (N.A.F); musthofiyah@mail.ugm.ac.id (M); artiwi@mail.ugm.ac.id (A.P.); novita@ugm.ac.id (N.K.); ragiladip27@mail.ugm.ac.id (R.A.P); aldyon.restu.a@mail.ugm.ac.id (A.R.A); yunyer@ugm.ac.id (Y.E)
  - ²Department of Animal Nutrition and Feed Science, Faculty of Animal Science, Universitas Gadjah Mada, Indonesia; muhlisin.fapet@ugm.ac.id
  ABSTRACT. This study aims to determine the enzymatic activity of extracellular alkaline protease from Bacillus cereus TD5B and its potential application as a sheep skin dehairing agent. The B. cereus TD5B was screened for extracellular alkaline protease production on skim milk agar media, while its alkaline protease activity and the application were measured at 1%, 1.5%, and 2%. The application of alkaline protease from B. cereus TD5B as a sheep skin dehairing agent was observed through histological examination and physical properties measurement after chrome-tanning with lime and Na₂S as control. The study was conducted in a completely randomized design, and the quantitative data were analyzed using Duncan’s Multiple Range Test. The results showed that a clear zone was seen surrounding B. cereus, indicating the bacteria’s proteolytic activity. The protease activity measurement showed that 2% of alkaline protease had the highest enzymatic activity at 144.75 U/mL/min. The highest tensile strength of sheep leather was obtained after dehairing at 1% alkaline protease concentration (350.26 kg/cm²), even though the highest elongation was obtained at 2% (34.92%). In contrast, different concentrations showed similar shrinkage temperatures at 90°C. This study concludes that the optimum alkaline protease concentration from Bacillus cereus TD5B as a sheep dehairing agent was 2%.
  
  KEY WORDS: Bacillus cereus TD5B, dehairing, alkaline protease, sheep skin
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EFFECT OF BADMINTON SHOE SOLE ON THE LUNGE SKILL PERFORMANCE: IN THE VIEWPOINT OF COORDINATION
- Pages 119-126
  Guanchun LIU¹, Yuqi LI², Quting HUANG², Jin ZHOU^{1, 2}*, Wing-Kai LAM³
  - ¹College of Electronics and Information, Sichuan University, Intelligent Control Institute, Chengdu 610065, China, 552750014@qq.com
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, China, zj_scu@scu.edu.cn
  - ³Li Ning Sports Science Research Center, Li Ning (China) Sports Goods Company, Beijing 101111, China, gilbertlam@li-ning.com.cn
  ABSTRACT. Badminton lunge requires rapid coordination between the knee and ankle joints and it is accompanied by fast contact between the shoe’s sole and the floor. Phase angle analysis is a protocol with high resolution and relating to the coordination, but how the shoe’s sole would affect the lunge performance was not clear in terms of coordination. Thereby, the aim of this study was to applied phase angle analysis to insight the lunge process, then to disclose the effect of badminton shoe’s sole on the lunge skill performance. Eleven elite badminton players performed five left-forward maximum lunge trials with wearing Rounded Heel Shoe (RHS), Flattened Heel Shoe (FHS), and Standard Heel Shoes (SHS). The motion capturing system was used to measure the knee and ankle kinematics information. The Phase Angle (PA), continuous relative phase (CRP) and variability of continuous relative phase (VCRP) between the knee and ankle joints were then calculated for both forward lunge phase and recovery phase in each of the three shoes. Current findings indicated that players wearing RHS had certain advantages on better movement coordination than other shoes, as indicated by better PA and CRP. The findings of this study would be helpful to understand the coordination of badminton lunges and explain the synergy between the lower extremity ankle and knee joint to minimize the possibility of injury in badminton. Furthermore, the coordination between the knee and ankle joints was greatly affected by the structure of the shoe heel design.
  
  KEY WORDS: phase angle, kinematics, coupling angle, lunging, footwear, badminton shoe
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