Leather and Footwear Journal

Volume 15, no 1

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Investigation of Children's Plantar Pressure Distribution with Varied Angle of Hallux
- Pages 3-14
  Jin ZHOU, Ting LI, Bo XU, Wuyong CHEN*
  - National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University; Chengdu P. R. China; rufuszhou.scu@gmail.com , wuyong.chen@163.com
  ABSTRACT. Fashion shoes with narrow and tight toe are widely designed for children and their influence was rarely considered. Therefore, the aim of this study is to investigate children's plantar pressure distribution with varied angle of hallux (AoH), so as to simulate the effect of the tight shoes on the children's feet. Totally, 892 healthy children aged between two and 11 were recruited and those with the foot deformities were excluded by an experienced clinical expert. Both the dynamic AoH and plantar pressure distribution were measured by a pressure plate, with the two-steps protocol and self-selected walking speed. Regions of Hallux, medial forefoot (MFF), central forefoot (CFF), lateral forefoot (LFF), mid foot (MF) and Heel were considered and peak pressure (PP) (N/cm2), relative pressure time integral (PTIrel) (%) and relative contact area (CArel) (%) at each region were calculated. All the subjects were classified into nine groups according to the AoH with the 5° interval and within groups variations for each plantar pressure parameters were examined by the One Way ANOVA. Our results show that within group differences of PP, PTIrel and CArel existed at the Hallux, MFF and MF and phenomenon of hallux off-load and MFF and MF over-load was observed. Overall, lateral shift of the hallux changed the pressure pattern at MFF and MF and the pressure rising at those two areas could hamper the normal development of the foot arch in both longitudinal and transverse. Therefore, straight and wider footwear should be recommended to children's parents.
  
  KEY WORDS: fashion shoes, children, hallux valgus, plantar pressure
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The Foot-Footwear Interaction in the Analysis of Foot Comfort and Footwear Quality
- Pages 15-24
  Alina IOVAN-DRAGOMIR*
  - Gheoghe Asachi Technical University of Iasi, Faculty of Textile, Leather and Industrial Management, 29 D. Mangeron Bd., Iasi, Romania, adragomir@tex.tuiasi.ro
  ABSTRACT. The aim of the study is to analyse the foot-footwear interaction. It has two different parts. The first part includes a foot health evaluation, using ESP questionnaire, a visual identification of the foot disorders and anomalies and the taking of the footprint and subsequent gait analysis. In order to exemplify this relation, a subject with foot anomalies was considered. The ESP score determined for the subject indicates a very good health status with minor health problems. Obviously, this score must be correlated with the age of the subject. The result of the ESP questionnaire justifies a deeper research because, in this case, the subject is young. The footprint analysis highlights a semi high arch foot and the gait analysis emphasizes two important abnormal aspects. The second part includes the analysis of a pair of shoes and the calculation of the shoe quality index. The calculation was carried out for a comfortable shoe with a lower degree of wear. The index can be calculated with or without input information from the subject. The results can be different and highlight the most important footwear requirements for the subject.
  
  KEY WORDS: foot, ESP questionnaire, gait analysis, quality index, footwear
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Performances of a Polysilicon Byproduct - Silicon Tetrachloride - on Swelling and Tanning Process
- Pages 25-38
  Bo TENG¹, Xiaoyun JIAN¹, Jinwei ZHANG¹, Wuyong CHEN^1,2*, Yinghong WANG³
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, 610065, Chengdu, China
  - ²Key Laboratory for Leather Chemistry and Engineering of the Education Ministry, 610065, Chengdu, China
  - ³College of Chemistry, Leshan Normal University, 614000, Leshan, China
  ABSTRACT. Sodium silicate was prepared with a polysilicon byproduct-silicon tetrachloride. The swelling property of the sodium silicate was then investigated including proteoglycan removing ability, silicon absorptivity, relative weight and thickness increase. Meanwhile, a new process for cleaner wet blue preparation was carried out. Properties of the wet blue such as mechanical properties, thermal stability and surface color were tested following the standard method. Chrome distribution of the wet blue was investigated with an inductively coupled plasma (ICP). A scanning electron microscope (SEM) and a atomic force microscope (AFM) were also used to illustrate the histological features of the wet blue. Finally, environmental impact of both swelling and tanning process were studied through COD, chrome contention, total solids and turbidity test. The results showed that the swelling ability of these silicate agents was distinctly related with their modulus. The lower the modulus, the better the swelling ability was shown, in terms of a higher relative weight and thickness increase, a better proteoglycan removing and a better silicon absorptivity. The SEM analysis indicated fiber bundles were fully opened with this silicate agent. For the wet blue prepared by new method, an equally quality data was shown compared with control, meanwhile, a lighter surface color, less and equally distributed Cr(III) were detected. More compact fiber bundles were shown on the SEM images. No obvious damage was detected in tropocollagen fiber structures through AFM analysis. Furthermore, compared with the traditional process, COD, total solids and turbidity data of both swelling and tanning effluent provided a lower value. The results could provide a feasible way for silicon tetrachloride recycling, also provide valuable references for clean production of leather industry.
  
  KEY WORDS: Silicon tetrachloride, Sodium silicate, Swelling, Tanning, Leather
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