Leather Pieces Research Articles

Characterization of Historical and Modern Leathers Using FTIR, XRD, SEM-EDX, and Thermal Techniques

Abstract A comprehensive study was conducted on four aged leather pieces of British origin that were utilized in book binding, dating back to the period between 1832 and 1860. The objective of this study was to characterize the thermal, structural, and deterioration properties of these historical leather fragments. Additionally, this study included two newly acquired leather samples of Indian provenance, proposed as potential replacements for this historical leather. The investigative process employed Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). Through the FTIR analysis, distinct spectral shifts were identified in the amide A band, indicating a disruption of hydrogen bonding within the aged leather. XRD diffractograms revealed the presence of amorphous phases in the aged leather specimens, signifying the deterioration of their triple helical structure. Notably, DSC analysis provided insight into the denaturation of the collagen-tannin matrix inherent to the historical leather, underlining the transformative effects of time on this intricate material composition. Under SEM analysis, cracks, fibre deterioration, and a general weakening in structural integrity were observed in the aged leather fragments. The EDX data identified one of the new leather samples as chrome-tanned, while the remaining samples exhibited characteristics consistent with vegetable-tanned leather.

EXAMPLES OF BAG DESIGN FROM WASTE LEATHER PARTS AS MATERIAL WITHIN THE SCOPE OF SUSTAINABILITY

Problems such as ineffective use of limited natural resources, pollution of natural water resources, global warming, pollution of soil and air necessitate the research of renewable, sustainable and usable alternative resources and techniques. Leather is a healthy, long-lasting, timeless material used in clothing, shoes, accessories and lifestyle products. Undesirable environmental wastes emerge due to the fact that leather businesses have liquid, gas and solid wastes, and the excessive use of chemicals and resources such as energy and water while transforming rawhides into leather products. Environmental wastes have increased the effective use of resources and the need for usable alternatives of waste materials in industrial areas in terms of sustainability. In the study in which the qualitative research method was used, an action research was conducted. Within the scope of the study, 8 bags were designed and produced from waste leather pieces. During the planning stage of the designs, the sketches of the bag forms were drawn at first. In the development of the designs, the general forms of the bags, the sizes, types and colors of the leather pieces were taken into consideration, and the patterns for creating the surface were studied. Colored waste Nappa leathers sized between 1.5 mm and 2 mm were used for bags. The tessellation method, one of the zero-waste design techniques, was used to obtain products from leather pieces in the study. The study aimed to contribute to both the environmental and economic aspects of sustainability with bag designs made with waste leather.

An improved automatic defect identification system on natural leather via generative adversarial network

ABSTRACT The past decade has witnessed an impetus in the rise of artificial intelligence techniques in a diverse range of computer vision-relevant applications. Specifically, automated optical inspection technology has been garnered substantial research attention due to its advantages of enabling amelioration in the manufacturing process and improving the efficiency of industrial production. To date, the studies and evaluations into the defects on the raw leather pieces involving observational analysis tend to rely heavily on domain experts who have undergone intensive training. Herein, an automatic inspection system is introduced to distinguish whether a leather patch contains any defective areas. In particular, the dataset involved in this experiment comprises a total of 375 images that are made up of three classes, viz, black line defect, wrinkle defect and non-defective. Notably, owing to the data scarcity issue, the Generative Adversarial Network (GAN) is adopted to discover the feature regularities to produce plausible additional training samples. The proposed algorithm is systematically analysed, and compelling performance is yielded when compared to previous works. Succinctly, with a relatively small amount of readily captured training data, the classification performance is capable of achieving 100% accuracy. As such, the proposed system may be served an appealing strategy, especially in dealing with leather defect recognition tasks.

Leather Defect Detection Using Semantic Segmentation: A Hardware platform and software prototype

Leather is a textile material made from the animal skins created through a process of tanning of hides. It is a durable material, and the price is higher compared to other types of textiles. The leather is highly sensitive to its quality and surface defect condition as it is expensive. The manual defect inspection process is tedious, labor intensive, time consuming, and often prone to human error. The aim of this research is to replace the manual process of leather inspection using fully automatic defect detection based on cutting-as machine vision techniques. The laboratorial platform consists of some mechanical components (conveyer or camera moving system), camera, lighting system, computing device (computer), and display system. In the proposed laboratorial platform, a conveyor system is used which is a fast and efficient mechanical handling apparatus for automatically transporting leather pieces during inspection. A camera is fitted above the surface of conveyor so that it can detect leather and capture and send to the computing devices. Then, a series of image processing will be carried out to detect defect detection which consist image pre-processing, training the deep learning models, and testing. The proposed semantic segmentation deep learning model was experimented using MVTEC leather dataset. We obtain 94% of Intersection of Union (IOU) in the experiments.

Scrap leather valorization through composite fabrication using mustard oil resin and N-vinyl-2-pyrrolidone

Composites derived from petroleum sources like epoxy, unsaturated polyester and phenolics have limitations due to non-biodegradability toxicity which have harmful effects on the environment; hence, there is a necessity to replace them with green composites. Presently, the synthesis of edible oil for resin formation and the use of scrap leather as reinforcement for composite fabrication are still not carried out. In this work, we have synthesized acrylate epoxidized mustard oil (AEMO) and blended it with crosslinker N-vinyl-2-pyrrolidone (NVP) using scrap leather pieces as reinforcement for composite fabrication. Characterization of mustard oil (MO), epoxidized mustard oil (EMO) and acrylate epoxidized mustard oil was carried out using iodine value, oxirane content, acid value, FTIR, NMR and viscosity. A ratio of 50:50 for AEMO:NVP and leather loading of 15%, 30% and 60% were used to make the composites. Increased leather loading showed improvement in mechanical properties in terms of higher tensile strength, Young’s modulus, flexural strength, flexural modulus and Izod impact values of 20.43, 1575.63, 48.14 and 3330 MPa and 0.22 kJ, respectively, at 60% loading. Biodegradability test indicated weight loss for all the composites with time recording a weight loss of 2.95%, 4.00%, 4.25%, 5.00% for 0% (neat), 15%, 30% and 60% loadings. TGA, DTA and DSC analysis proved excellent thermal stability at higher loading. Excellent bonding at lower loadings was observed by morphological analysis. An increase in storage and loss modulus and a decrease in tan δ with broadening of the peak for higher loadings were noted. Chemical resistance test gave no deterioration of the samples except with acids.

Leather-Promoted Transformation of Glucose into 5-Hydroxymethylfurfural and Levoglucosenone.

The search for efficient catalysts frequently leads to new homogeneous and heterogeneous catalysts of increasing complexity, and sometimes common, natural, or hybrid natural/synthetic materials that could be used in catalysis are overlooked. For example, the leather industry has produced robust Cr-containing materials for centuries by chemical treatment of animal hides with chromium salts. Herein, the use of chromium-tanned leather as a heterogeneous catalyst for glucose dehydration to 5-hydroxymethylfurfural (5-HMF) and levoglucosenone (LGO) is reported. Four pieces of waste leather were obtained from shoe soles and a belt, characterized by a range of techniques including FTIR spectroscopy, SEM, BET surface area measurements, XRD, and X-ray photoelectron spectroscopy, and their catalytic activity was evaluated. The activity of the scrap leather pieces compares favorably to those of many recently reported catalysts for the preparation of 5-HMF, but additionally results in significant quantities of LGO. Overall, the results demonstrate that waste leather is an outstanding material for use in catalysis.

A Study on the Design of Accessories through the Concept of Reincarnation

This study aims to explore the unethical issues in leather processing and to develop designs of leather products based on the concept of reincarnation by ecosystem circulation. The method used in this research include the review of previous literature and the design process for development fashion accessories using waste leather. The design process comprises collecting waste leather, classifying waste leather by type, color, and size, and developing leather products according to line carnation method. For this research, the material was limited to waste cowhide leather collected from leather workshops and leather product factories. The leather pieces were divided into typical and atypical types and developed leather accessories based on the leather piece’s color and size. A twill brooch, four-string bracelet, a brooch using the four-stringed leather strap and mini handbag designs were developed using regular type waste leather. An armband of abstract patterns and a cellphone case with graffiti pattern using irregular type over-splitting waste leather. The environmental issues in design are observed as part of understanding the significance of this study. Development of waste leather accessory can expand the usability of the waste leather as well as increase the product value by creating limited-line editions. By understanding the role and benefits of sustainable upcycling, this research suggests an efficient way to use waste materials in fashion to coexist with the natural environment.

PRÁCTICAS MORTUORIAS DE CAZADORES-RECOLECTORES TARDÍOS DE LOS DESIERTOS DE ALTURA DEL NOROESTE ARGENTINO: EL FARDO FUNERARIO DE QUEBRADA SECA 3

Se presentan el análisis bioarqueológico y las características de un fardo funerario recuperado en el abrigo rocoso Quebrada Seca 3 (Antofagasta de la Sierra, Catamarca, Argentina), con fechados entre 4900 y 4400 años AP, correspondiente a cazadores-recolectores en tránsito a la producción de alimentos. Los objetivos son abordar las características bioarqueológicas del individuo, describir el fardo y su contenido y establecer el tipo de depósito funerario.
 El fardo es descripto y graficado mediante fotos y dibujos y se incluyen observaciones tafonómicas. Los restos humanos contenidos en el fardo se analizaron para establecer el número mínimo de individuos (NMI), medidas de abundancia taxonómica y relativa, estimación de edad y posible causa de muerte. Para definir el tipo de depósito funerario se contrastaron datos de campo y características del fardo con bibliografía especializada. El fardo funerario consiste en dos cueros de camélido, uno usado como cobertura externa y otro como envoltorio de los restos óseos humanos. Ambos cueros conforman un “paquete” atado con dos cordeles y rodeado y cubierto por haces de gramíneas. Los restos humanos hallados dentro del fardo arrojaron un NMI de 1, menos del 65% de representación ósea y una edad estimada de 28semanas de gestación. La posible causa de muerte de este feto habría sido su inviabilidad por parto prematuro. El depósito funerario es de tipo secundario en el que la manipulación antrópica está referida únicamente a la desarticulación del esqueleto al ser colocado en el fardo.

Computational Fluid Dynamic Analysis of Swirl Vane Gripperd

The swirl vane gripper is a recently developed robotic handling device that generates swirling air flow to create upward lifting force. The lifting force is used to pick up and hold a workpiece without any contact with the gripper face. It is useful in semiconductor manufacturing industry and food processing industry because of its ability to handle the products without any damage. In present work the Computational Fluid Dynamics (CFD) analysis is carried out in the Ansys software to study the negative pressure that creates the lifting force. In this study the negative pressure distributions are estimated for the various speed of swirl vanes by using Ansys software. And also the lifting forces are established for various gap clearance between the workpiece and the swirl gripper using CFD. The swirl vane gripper is fabricated and an experimental study has been made in a six-axis robot to check the amount of lifting force developed for holding the leather pieces.

KAJIAN PENGARUH KONSENTRASI Rhizopus sp. SEBAGAI AGEN PENGIKIS PROTEIN TERHADAP MUTU KULIT IKAN GURAMI TERSAMAK

The study aimed to assess the effect of protease activity of Rhizopus sp. as a bating agent on the tanned carp leather quality, and their use for commercial leather products. The study was designed with a completely randomized design with four treatment, namely: the concentration of protease from Rhizopus sp. 0.5% (a1), 1.0% (a2), 1.5% (a3) and palkobat 1.0% (a4/control) with 3 replications. Parameters were observed that is (1) protease activity of Rhizopus sp and palcobat; (2) Thickness (mm), tensile strength (N/cm2), tear strength (N/cm), elongation (%), enervation (mm), shrinkage temperature (ºC), fat/oil content (%) of tanned leather; and (3) level of consumer acceptance (%) and added valuead of comercial leather product. The data of tanned leather quality is then compared with SNI 06-4586-1998 concenring freshwater snake skin leather and chrome Burk’s Bay (1996) on the raw material quality leather products. The test results of protease activity of Rhizopus sp. = 7.97 mg/50mg/ jam and palkobat = 13.62 mg/50 mg/hour. The results of the analysis of tanned leather carp qulity sample from each treatment and comparison with the SNI as follows: (1) Thickness: 0.41 (a1), 0.38 (a2), 0.43 (a3), 0.41mm (a4) and ≥ 0.22 (SNI 06-4586-1998). Tensile strength: 1682.67; 1818.17; 1195.57; 1670.55 and 1,000N/cm2 (SNI). Tear strength: 314.87; 310.95; 332.06; 462.22, and 150.00 N/cm (SNI). Elongation: 93.33; 62.67; 56.67; 97.33, and <30.00% (SNI). Enervation: 1.87; 2.20; 1.63, 2.49, and ≥ 2.0 mm (Burk’s Bay, 1996). Shrinkage temperature: 74.00; 95.33; 96.33; 97.33, and ≥ 70.33ºC (SNI). The fat/oil content: 7.84; 8.17; 5.25; 8.49, and 2.00 to 6.00% (SNI). All treatments were tested has met the SNI quality, except elongation and fat/oil content. The level of consumer acceptance of the Oval HP Cover that is (1) aspects of the display (76.67% like and 23.33% dislike), (2) the use of convenience (66.67% like and 33.33% dislike ), and (3) price (63.33% accepted and 23.67 reject). The level of consumer acceptance of the Box Cover HP models that is (1) aspects of the display (80.00% like and 20.00% dislike), (2) convenience of use (86.67% like and 13.33% dislike), and (3) price (66.67% accepted and 33.33% reject). The economic value of tanned carp leather as big as Rp 160.000/20 leather pieces and leather products as big as Rp 420,000 per 15 pieces of product.

The Ethiopian lyre Bagana. An ethno-acoustical study

The Ethiopian lyre bagana is usually finger-plucked and monodic, with a skin soundboard and ten gut strings tuned to low-frequency pitches (ca 50-150 Hz). Its most important sonorous characteristic is its buzzing sounds, produced thanks to leather pieces placed between each string and the wide bridge. This study is based on a corpus of sounds produced by eight different instruments played by a virtuoso master and recorded in situ with and without the leather pieces. The sounds have been analyzed through calculation of several timbre descriptors based on time-domain, sinusoidal harmonic model and short-time Fourier transform representations. These results have been compared with ethnomusicological analyses of the repertoire and the socio-cultural aspects of the bagana, in order to understand how the sound qualities are dealt with by the players. These joint analyses show that the very distinctive buzzing quality of the bagana sounds can be linked with auditory roughness and inharmonicity descriptors (indicating that it is not due to noise but rather to quasi-harmonic components) while the significant timbre variation between sounds is mostly due to differences in string quality, location of the leather pieces on the bridge and musicians' need to produce the longest possible duration.

Triadic and collaborative play by gorillas in social games with objects

Interaction with others over objects has until recently been thought lacking in the social play of non-human great apes, in contrast to that of children; even now, only bonobos have been observed to engage in social play involving objects. Human children's triadic interactions with objects involve joint attention, showing and giving, communication that maintains interaction, and sharing of emotions and experiences. We question assertions that chimpanzees, and non-human great apes in general, lack the key characteristics of children's collaborative play. Here, we show that zoo gorillas play games that are both triadic and collaborative. These games were videotaped at the San Francisco Zoo in five different years and involved five different pairings of gorillas. The context was in most cases playfully competitive, involving objects such as balls, bags and leather pieces as foci of joint attention; the ostensible goal in most games was to gain or keep possession of a particular object. In some episodes, roles as possessor or pursuer of an object were exchanged many times; in others, one gorilla retained possession of an object but encouraged pursuit from a partner. Through gaze and gesture, gorillas invited others to: share interest in and attention to objects; share patterns of play; and re-engage after breaks in play. Sometimes, gorillas would assist others in their efforts to engage in collaborative play: older gorillas encouraged younger partners by 'self-handicapping' their own actions. Collaborative games may occur later in the ontogeny of gorillas than in humans, and depend on the challenges and artifacts available in a particular group's habitat.

Proposal of wet blue leather remainder and synthetic fabrics reuse

This work presents the development of a leather remainder reuse process which consists of joining leather pieces into layers through the use of the hot melt technology. By using this process, it is possible to obtain some material which preserves the leather flexibility and strength properties. This innovative and incremental process aims at the remainder reuse which would normally be discarded. The great benefits of the hot melt applied to the leather remainders are as follows: skipping the barb cutting step, reducing time in the sewing process, and minimizing the impact on the environment.

Small-scale field trial of a sensing device for detecting peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in northwestern Argentina.

Two prototypes of sensing devices for detecting peridomestic populations of Triatoma infestans Klug were tested in paired trials with bamboo canes in Amamá and nearby rural villages under triatomine surveillance. In infested peridomestic structures housing domestic animals, 1-2 pairs of numbered devices were placed per test site, left for 3-9 nights, and inspected for evidence of infestation. Prototype A was a black plastic cylinder 19 cm high and 10 cm diameter, with a screw cap on the top, 2 openings in the bottom, and a removable central structure made of resistant plastic coated with leather. Prototype B had square leather pieces rolled into cylinders instead of the central structure. Prototype A was significantly more sensitive than the bamboo cane with pleated paper inside in 13 test sites in which 20 pairs were tried. In a smaller series involving 7 pairs, prototype B also detected infestations more frequently than the cane. Triatomine feces were the signs most frequently recorded by both prototypes, whereas the bamboo canes recorded no feces. Ten T. infestans and 1 Triatoma guasayana Wygodzinsky & Avalos were collected from the prototypes placed on the ground or walls, not beneath the thatched roofs of the animal shelters, whereas only 3 T. infestans were collected from the canes. This study describes an effective sensing device for detecting T. infestans populations in outdoor animal shelters and provides quantitative field data on its performance.

亜硫酸パルプ廃液鞣剤化の研究

For the investigation of tannin sorption by wet cationic chrome leather. the authors used horse leather which had been tanned with chrome alum and soda ash and which possessed 4.69% combined Cr2O3 on collagen basis, shrinking temperature (Ts) 100°C, and about 70% water. One hundred and fifty grams of the above-mentioned leather pieces were retanned by the rotating machine for 4 hrs with 200cc of 10% tannin containing blended tan liquor of equal tannin proportion at the natural and the adjusted values of pH. After vegetable retanning, we analyzed the exhausted tan liquors, determined the gallic-acid value (G-A. V.) or ethyl-acetate value and calculated the amount of component tannin in the liquors. The following results were obtained:1. Chestnut-Wattle blend. There was a preferential sorption of chestnut at the natural pH of 3.6-4.5, but both components were equally consumed at the adjusted pH of 5.0-5.1.2. Chestnut-Soluble Quebracho blend. It was observed that soluble quebracho was sorbed preferentially at the natural pH of 3. 5-4. 5, but not at the adjusted pH of 5.1-5.2.3. Chestnut-Mangrove blend. There was a slight preferential sorption of chestnut at the natural pH of 2.9-4.5 but a much more sorption at the adjusted pH of 4.9-5.1.4. Chestnut-TOTANIN blend. Both components were equally consumed at the natural pH of 2.9-4.6, whereas chestnut was preferentially sorbed at the adjusted pH of 5.2-5.2.5. Wattle-Soluble Quebracho blend. Vigorous consumption of wattle was observed at the adjusted pH of 3.8-4.0 and the naturel pH of 5.3-4.9.6. Wattle-Mangrove blend. Wattle was preferentially sorbed at the adjusted., pH of 3.6-3.4 and also at the natural pH of 4.4-4.4.7. Wattle-TOTANIN blend. A preferential consumption of wattle was much more at the natural pH of 3.6-4.3 than at the adjusted pH of 5.1-5.3.8. Soluble Quebracho-Mangrove blend. A preferential sorption of soluble quebracho was vigorous at the adjusted pH of 3.7-3.9 as well as at the natural pH of 5.0-4.8.9. Soluble Quebracho TOTANIN blend. Both components were consumed equally at the natural pH of 3.6-4.6 and the adjusted pH of 5.0-5.0.