Volume 20, no 1

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    STUDY ON COMFORT EVALUATION METHODS OF DIFFERENT WOMEN’S HIGH-HEELED SHOES BASED ON ELECTROENCEPHALOGRAPH (EEG) TECHNOLOGY
    • Pages 5-14
      Xiangdong LUO1, Sun YUN1, Chaohua XUE1, Zongmin YUE2, Huijun REN2
      • 1College of Art & Design, Shaanxi University of Science and Technology, Xi’an, Shaanxi, P. R. China 710021
      • 2College of Arts & Sciences, Shaanxi University of Science and Technology, Xi’an, Shaanxi, P. R. China 710021

      ABSTRACT. The 24-27-year-old women with 230-235 mm feet with the similar level of education were selected for the study. During the test, those subjects were tested by SD semantic differential measurement method and BP EEG signal acquisition system. The brain electrical rhythm characteristics and the subjective comfort feelings in the states of static standing and uniform natural walking were tested. The experimental results show that the heel mechanical changes caused by the heel height and the motion states are negatively correlated with the α wave intensity of the brain while the subjective comfort evaluation is negatively correlated with the α wave intensity in the parietal and occipital regions. The research results reveal that EEG technology is used to evaluate the comfort of wearing high-heeled shoes, which can not only make up for the lack of the subjective evaluation method, but also improve the comfort evaluation system of wearing shoes and boots. All these have the important theoretical and practical significance for the footwear comfort evaluation.

      KEY WORDS: high-heeled shoe, comfort, plantar pressure, electroencephalograph (EEG)
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    OPTIMIZATION OF ALKALINE HYDROLYSIS OF CHROME SHAVINGS TO RECOVER COLLAGEN HYDROLYSATE AND CHROMIUM HYDROXIDE
    • Pages 15-28
      Julio BARRA HINOJOSA*, Liliana MARRUFO SALDAÑA
      • Productive Innovation and Technological Transfer Center of Leather, Footwear and related industries (CITEccal Lima), Technological Institute of Production (ITP), Caquetá Ave. 1300, Rímac, 15094, Lima, Perú, lmarrufo@itp.gob.pe, julio.barra.h@uni.pe

      ABSTRACT. The tanning industry uses skins and hides from cattle, sheep, among others, which are a byproduct of the meat industry. In their production process, they generate wastewater and solid wastes in significant quantities, that require alternatives for their adequate treatment. The present research was developed to optimize the alkaline hydrolysis process of chrome leather shavings to recover collagen hydrolysate and chromium salts, and to identify the relation between the response variables and hydrolysis conditions. For this purpose, a preliminary study was carried out, where alkaline hydrolysis conditions were adjusted, then these were optimized through a factorial design and scaled up the process to a pilot level. The preliminary study of alkaline hydrolysis of the sample was performed, where reaction time and sodium hydroxide concentration were established as factors to adjust the process. The optimization of this method was developed through a factorial design with two response variables: percentage of recovered collagen protein (PRCP) and percentage of residual chromium (PRC) present in the collagen hydrolysate. Thus, the optimum alkaline hydrolysis conditions were obtained: 70°C, 0.47 M NaOH and 90 minutes for the reaction, and the relation between the response variables. Finally, the process was carried out in a pilot scale in which 45 L of collagen hydrolysate was recovered, with 87.16% of recovered collagen protein and 1.17% of residual chromium.

      KEY WORDS: waste valorization, chrome shavings, alkaline hydrolysis, tanning process
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    RESEARCH ON THE USE OF TANNED LEATHER FIBRES AS AGGREGATE IN OBTAINING ASPHALT MIXTURES
    • Pages 29-36
      Gabriel ZĂINESCU1, Rodica Roxana CONSTANTINESCU1, Carmen RĂCĂNEL2, Dana DESELNICU3
      • 1INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu Str., 031215, Bucharest, Romania
      • 2Faculty of Railways, Roads and Bridges, Technical University of Civil Engineering of Bucharest, carmen.racanel@utcb.ro
      • 3Politehnica University of Bucharest

      ABSTRACT. The current tendency of road builders and managers is to make asphalt mixtures with improved performance in terms of aging and fatigue resistance, better traffic behavior both in summer and in winter, as well as increased values for dynamic properties: elasticity, tracking, etc. In this sense, there is a permanent concern to find new materials and technologies for the preparation and implementation of asphalt mixtures that convey the desired properties to the layers. In this sense, the addition of microfibres and fibres, with dimensions ranging from 0.01-10 mm when preparing asphalt mixtures, transforms the bituminous binder used into a “composite material”, in which the matrix is the bitumen, and fibres are the dispersed phase, leading to the stabilization of the bitumen inside the mix, as well as to the reinforcement of the asphalt mixtures, giving them special properties. The paper presents laboratory experiments for obtaining smart biocomposites (leather fibres-asphalt mixtures) with applications in the field of road infrastructure. The resulting biocomposites were characterized by chemical, physical-mechanical and structural analyses.

      KEY WORDS: asphalt mixture, tanned leather fibres, biocomposites, leather waste
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    STUDY ON THE CREEP BEHAVIOUR OF NAPPA UPPER PIG LEATHER
    • Pages 37-42
      Keyong TANG1*, Weilin LI1, Fang WANG1, Jie LIU1, Mădălina G. ALBU2
      • 1College of Materials Science and Engineering, Zhengzhou University, Henan 450001, P. R. China, keyongtangzzu@yahoo.com
      • 2INCDTP – Division: Leather and Footwear Research Institute, Collagen Department, 93 Ion Minulescu St., 031215, Bucharest, Romania

      ABSTRACT. From viewpoint of creep behavior, the visco-elasticity of nappa upper pig leathers is studied. A series model with three Kelvin models is proposed and has been used to imitate and describe their creep behavior successfully. The Kelvin model is a parallel connection model with a spring model and a dashpot model. The interrelated indexes of the imitation are favorable. It means that the imitation is reliable.

      KEY WORDS: nappa upper pig leathers, visco-elasticity, creep behaviour, Kelvin model
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    EFFECT OF MICROWAVE IRRADIATION ON THE SOLUTION OF AMINO ACID CHROMIUM COMPLEXES
    • Pages 43-50
      Sujun WANG1, Wuyong CHEN1, 2, Luming YANG **1, 2, Jinwei ZHANG1, 2*
      • 1Key Laboratory of Leather Chemistry and Engineering of the Ministry of Education, Sichuan University, Chengdu, 610065, P. R. China
      • 2National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P. R. China

      ABSTRACT. In recent years, microwave technology has been applied more and more in tanning, however there is still a lack of research on the effect of microwave irradiation on the interaction between chromium complex and amino acids. In the study, the influences of microwave irradiation on the reactions were studied by selecting four kinds of characteristic amino acids in collagen, aspartic acid, hydroxyproline, lysine and glycine, to provide new knowledge on tanning process. The solution of chromium complex reacted with amino acid was heated by microwave as a sample and by water bath heating under the same conditions as a control. During the process, the pH variation and UV-Visible absorption spectrum were used to determine the influence of microwave on the reaction between amino acids and chromium complex. The results demonstrated that both microwave irradiation and water bath could accelerate the reaction rate and promote the stability of the amino acid chromium complex. However, the microwave irradiation had much more obvious effects on these changes than the water bath, indicating that microwave irradiation could promote the reaction between amino acid and chromium complex further and make the formed amino acid chromium complex more stable. In addition, microwave had stronger effect on improving the reaction when the polarity of amino acid was larger. In short, this study would provide some hints for understanding how microwave affects chrome tanning and might be useful to apply microwave in tanning in future.

      KEY WORDS: microwave, amino acid, chromium complex, complex stability
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    FASHION REVOLUTION AS PROMOTER OF SOCIAL INNOVATION AND SUSTAINABILITY IN FASHION
    • Pages 51-58
      Solange FERNANDES1*, Isabela Dias HONÓRIO2, Alexandra CRUCHINHO2, Maria José MADEIRA1, José LUCAS1
      • 1University of Beira Interior, Covilhã-Portugal
      • 2State University of Londrina, Londrina, PR-Brasil
      • 3Polytechnic Institute of Castelo Branco-Portugal

      ABSTRACT. Fashion Revolution is a global collaborative movement that seeks to increase transparency across industry’s production chain and counteract misunderstanding. The movement calls university students around the world to become ambassadors and to become activist designers. Also, students, teachers, businesses, professionals and the community to discuss consumption, sustainable development of fashion and getting millions of people demanding fashion transparency, through brand questioning: #whomademyclothes. This article aims a fashion week revolution, promoting knowledge as social innovation for sustainability when launching a concept as a business value proposition. Authors present a CANVAS and Pestle business model to support future implementation of this conceptual idea. One concludes that design of product-service systems, allied to fashion revolution movement, helps foster social innovation, stimulates circularity, induces behavioural consumption changes, promotes dematerialization of energy consumption, redistribution of idle products, available resources management with social and environmental benefits, through online platform and app.

      KEY WORDS: activism design, systems design, social innovation, 2P2 platform
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    PRODUCTION OF MULTIFUNCTIONAL FOOTWEAR FOR PRISON POLICE OFFICERS
    • Pages 59-64
      Mirela PANTAZI-BĂJENARU*, Traian FOIAŞI, Dana GURĂU
      • INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, 031215 Bucharest, Romania, pantazimirela@yahoo.com

      ABSTRACT. There is a close connection between the comfort in wearing footwear and the quality of this product. When we refer to the quality of footwear, we must start from the analysis of materials used to make the upper and lower shoe assembly, the analysis of how the joints between the different elements of the assembly behave and finally we must consider the behavior of the shoes as a whole. The footwear must create a climate where temperature, humidity, air circulation and their action on the foot, and on the whole body are correlated. Even at a rapid change of internal or external influences, the wearer must feel good. The so-called triple physiological agreement - temperature, humidity and air circulation - must be adaptable to various requirements during a working day such as: rest, movement, physical effort and climatic conditions. The design of a product is not only related to the aesthetic, artistic aspect, but more to its functionality and engineering (from the correct choice of materials, construction and technological concept, to prototyping). A good example in this regard is the design of multifunctional footwear, for soldiers and police officers. Therefore, designing the right footwear is a big challenge not only for designers, but also for engineers. The paper presents the way in which footwear as a component of the work uniform of prison police officers was made.

      KEY WORDS: multifunctional footwear, materials, specifications
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    AGE-RELATED INFLUENCE OF OBESITY ON PLANTAR PRESSURE IN CHILDREN AGED 7-14
    • Pages 65-72
      Yihong ZHAO1, 2, Hao LIU1, Shiyang YAN1, 2, Ruoyi LI1, 2, Luming YANG1, 2*
      • 1National Engineering Laboratory for Clean Technology of Leather Manufacture, Chengdu, 610065, China
      • 2Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Chengdu, 610065, China

      ABSTRACT. Obesity is an important factor influencing foot geometry and function, especially for children whose musculoskeletal system are experiencing growth and maturation. The objective of this study was to examine the development of plantar pressure for the obese and normal-weight children aged 7-14 years, and the difference between the two groups in this developing duration. Totally 288 children (138 normal-weight and 150 obese) were included into the data analysis. Plantar pressure measurements were performed during barefoot walking in a self-selected speed. Contact areas, pressure-time integrals (PTI) and force-time integrals in ten plantar regions were obtained to calculate the arch index (AI) and the relative force-time integral (relFTI). Results showed that: the AI and PTI were evidently higher for obese children compared to the normal-weight group. The AI seemed to be even with age for both groups. PTI values of both groups elevated with increasing age and significance appeared from the age of 11. RelFTI values were significantly higher in lateral forefoot (M3-5) and midfoot (MF) for obese children. And the age-related changes of relFTI were different in obese children compared with normal weight ones. Obesity would obstruct normal age-related development of plantar pressure distribution.

      KEY WORDS: obesity, children, footwear design
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    MODIFICATION OF WATERBORNE PU FINISHING AGENT WITH HYDROXYL SILICONE
    • Pages 73-82
      Keyong TANG1**, Weilin LI1, Fang WANG1, Mădălina G. ALBU2
      • 1College of Materials Science and Engineering, Zhengzhou University, Henan 450001, P. R. China, keyongtangzzu@yahoo.com
      • 2INCDTP – Division: Leather and Footwear Research Institute, Collagen Department, 93 Ion Minulescu St., 031215, Bucharest, Romania

      ABSTRACT. In the present paper, a waterborne polyurethane (PU) finishing agent was synthesized with isophorone diisocyanate (IPDI), polytetrahydrofuran (PTMG), dimethylol propionic acid (DMPA) and n-butylamine, in which hydroxyl-terminated polydimethylsiloxane (OHterminated PDMS) was added in three different ways, i.e., one-step, two-step and as a chain-extension agent. The PU was characterized using FT-IR and DSC and the water resistance and dry/wet rubbing resistance of the PU films were studied and compared. It was found that the chain segments by the reaction with OH-terminated PDMS and IPDI act as hard segments, and the elongation at break and water resistance of PU with OH-terminated PDMS as chain-extension agents are better than those with OH-terminated PDMS in both ways of one-step and two-step. The elongation at break could reach 1300% with the water absorption of only 1/4 of the latter PU films, when the same amount of OH-terminated PDMS is added in the system. It is better that OH-terminated PDMS is added in the top layer than added in the middle layer. The dry rubbing resistance could reach grade 5 with the wet rubbing resistance of grade 4.5.

      KEY WORDS: waterborne polyurethane, polyurethane (PU), finishing agent, hydroxyl-terminated polydimethylsiloxane (Hydroxyl silicone)
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