Hasil untuk "Textile bleaching, dyeing, printing, etc."

Hiroki Maru, Takumi Yuasa, Hiroyuki Kanai

Heat exposure in summer increases the risk of heat strain during work and rest, highlighting the need for effective cooling strategies. This study evaluated the cooling effectiveness of a fan-cooling jacket (FC) and a thermoelectric neck cooler (NC) under resting conditions in a hot and humid environment. Six healthy males completed three trials (no cooling, FC, and NC) in an environmental chamber (35 °C, 70% RH). Thermophysiological responses (mean skin temperature, armpit temperature, sweat volume) and psychological ratings (thermal comfort, wetness sensation) were simultaneously assessed. FC significantly reduced mean skin temperature, attenuated the rise in axillary temperature, and decreased sweat volume while also improving thermal comfort and wetness sensation. In contrast, NC provided only transient improvements in comfort and did not suppress the rise in axillary temperature; wetness sensation deteriorated over time, likely due to its localized and limited cooling area. These findings indicate that, under low-activity conditions, broad-area forced convection cooling is more effective for mitigating heat stress than localized neck cooling. The results highlight the practical utility of fan-cooling garments for rest periods and other low-intensity scenarios.

Miljković Milena, Trajković Dušan, Nikodijević Milena et al.

In this study, the dyeing of polyester knitted fabric in one-component - red dye, two-component - red + yellow dye and three-component dyeing system - red + yellow + blue dye was investigated. Polyester is one of the most commonly used synthetic fibers. It has a hydrophobic nature and excellent mechanical properties such as tensile strength and excellent wear resistance. These fibers are usually dyed with disperse dyes that are poorly soluble in water and it is necessary to add auxiliary agents for better solubility. In the experimental part, 100% polyester knitted fabric was used, which was dyed with one, a mixture of two and a mixture of three disperse dyes with the addition of acetic acid and a dispersing agent. The dyeing time was 60 min, while the dyeing temperature was 135 °C. The bath ratio was 1:20. The dye concentrations were 1 and 4%. The dyeing efficiency was analyzed through the K/S values and CIELab parameters. Based on the obtained results, sample dyed with 4% dye in the three-component dyeing system has the highest K/S value.

Md Atiqur Rahman, Mamadou Ndiaye, Bartosz Weclawski et al.

This study explores the impact of alkali treatment on the physical, thermal, flexural, and thermo-mechanical properties of Borassus flabellifer husk fiber-reinforced epoxy composites in accordance with standards. Using the hand layup method, composites were fabricated with 10% (wt.) untreated and alkali-treated fibers (0.25–2 hours). SEM analysis confirmed improved fiber-matrix adhesion, leading to enhanced properties. Treated fiber composites exhibited reduced moisture regain (0.57−1.28%) and water absorption (0.59−1.55%), indicating superior moisture resistance. Thermal stability increased with alkali treatment, with integral process decomposition temperature (IPDT) reaching 547°C for 2-hr treated fibers. The glass transition temperature (Tg) peaked at 94.5°C for the 0.5-hr treated Borassus fiber-reinforced epoxy (0.5TBHFE). Flexural modulus (up to 3.2 GPa) and strength (up to 108.7 MPa) exceeded many conventional bio-fibers-reinforced composites, making them rational for structural applications. Dynamic mechanical analysis showed enhanced damping properties (tan δ up to 1.21), improving energy dissipation and impact resistance. Overall, 0.5TBHFE offered an optimum balance between stiffness and damping, making it suitable for aerospace and automotive applications. This study highlights the potential of Borassus husk fibers as a sustainable reinforcement alternative, though further optimization and industrial processing are needed for broader application.

Radmila Žižková, Baturalp Yalcinkaya, Eva Filová et al.

Electrospinning has advanced from a lab technique to an industrial method, enabling modern filters that are high-performing, sustainable, recyclable, and non-toxic. This study produced recycled PA6 nanofibers using green solvents and incorporated non-toxic CuO nanoparticles via industrial free-surface electrospinning. Polymer solutions with concentrations of 12.5, 15.0 and 17.5 (<i>w</i>/<i>v</i>)% were electrospun directly onto recyclable polypropylene spunbond/meltblown nonwoven substrates to produce nanofibers with average fiber sizes of 80–250 nm. Electrospinning parameter optimization revealed that the 12.5 wt.% PA6 solution and the 2–3 mm·s⁻¹ winding speed had the optimal performance, attaining 98.06% filtering efficiency and a 142 Pa pressure drop. The addition of 5 wt.% CuO nanoparticles increased the membrane density and reduced the pressure drop to 162 Pa, thereby improving the filtration efficiency to 98.23%. Bacterial and viral filtration studies have demonstrated pathogen retention above 99%. Moreover, antibacterial and antiviral testing has demonstrated that membranes trap and inactivate microorganisms, resulting in a 2.0 log (≈approximately 99%) reduction in viral titer. This study shows that recycled PA6 can be converted into high-performance membranes using green, industrial electrospinning, introducing innovations such as non-toxic CuO functionalization and ultra-fine fibers on recyclable substrates, yielding sustainable filters with strong antimicrobial and filtration performance, which are suitable for personal protective equipment and medical filtration.

G. Rameshkannan, S. Ramesh Babu, P. Senthamaraikannan et al.

Natural fibers have gained popularity in composites because they are inexpensive, lightweight, and biodegradable. However, challenges such as poor bonding and high moisture absorption persist. This study addressed these issues by treating aerial roots of Ficus amplissima fibers (ARFAFs) with a 5% NaOH solution at various fiber weight percentages (5%, 10%, 15%, 20%, and 25%). The study found that alkali treatment improved the bond between the polymer matrix and the fibers, resulting in increased tensile, flexural, and impact strength, which improved from 44.76 to 46.71 MPa (4.36% improvement), from 59.38 to 63.12 MPa (6.29% improvement), from 85.66 to 92.22 J/m (7.66% improvement), respectively. Additionally, water absorption was reduced compared to untreated fibers. The tribological behavior of ARFAF composites was investigated using a pin-on-disc machine. The experiments were designed using the Taguchi method, and analysis of variance was conducted utilizing Minitab 19 software. Four factors were considered: fiber weight percentage, load, sliding speed, and sliding distance, each at three levels. Results revealed that the applied load was the most significant variable, contributing 41.72% to the sliding wear of the composites. Furthermore, a higher fiber weight percentage improved the wear resistance, resulting in a less mass loss.

Pavel Surynek, Vojtěch Bubník, Lukáš Matěna et al.

We address the problem of object arrangement and scheduling for sequential 3D printing. Unlike the standard 3D printing, where all objects are printed slice by slice at once, in sequential 3D printing, objects are completed one after other. In the sequential case, it is necessary to ensure that the moving parts of the printer do not collide with previously printed objects. We look at the sequential printing problem from the perspective of combinatorial optimization. We propose to express the problem as a linear arithmetic formula, which is then solved using a solver for satisfiability modulo theories (SMT). However, we do not solve the formula expressing the problem of object arrangement and scheduling directly, but we have proposed a technique inspired by counterexample guided abstraction refinement (CEGAR), which turned out to be a key innovation to efficiency.

Gizie Abeje, Alemayehu Zewodu

Flax is a versatile crop grown for its fiber and seed oil. Despite extensive conservation efforts in Ethiopia, the genetic potential of flax accessions conserved in the gene bank remains largely underexplored for fiber and seed yield. Here, we aimed to assess the genetic variability and association of morpho-agronomic traits and identify potential accessions for fiber and seed yield among 150 flax accessions. The study was conducted at Holeta Agricultural Research Center during 2022/23 growing season using an augmented design. Data were collected on flowering and maturity dates, plant and technical height, basal and secondary branch, boll and seed numbers, 1000-seed weight, and yield. Results revealed significant variation both between blocks and within treatments, with flowering time, maturity, plant height, boll number, seed weight, and yield contributing for the highest variability (58.7%). Cluster analysis revealed nine distinct genetic groups, each exhibiting specific trait patterns. Seed yield had strong associations with maturity, plant height, and boll number. High broad-sense heritability for days to flowering, plant height, and yield traits suggests selection could be effective based on phenotypic expressions. The study highlights the potential of Ethiopian flax genetic diversity for enhancing fiber and seed yield, suggesting effective selection based on key traits.

Megan Wolfe, Huantian Cao

This research developed shoe soles using a biodegradable and renewable composite made of King Oyster mushroom mycelium. An exploratory approach was used to develop biodegradable shoe prototypes using the mushroom mycelium composite as the midsoles. An online survey was conducted to evaluate the consumer acceptance of the shoe prototypes and a wear test with undergraduate college students was conducted to evaluate the consumer acceptance, wearability, and comfort of the shoe prototype. The survey results indicated that consumers liked the new sustainable footwear and were likely to purchase it. Indian consumers liked the new shoes more and would be more willing to purchase the new shoes than the U.S. consumers. The young age group would be more willing to buy this sustainable shoe prototype than the old age group. The consumers who were frequent consumers of sustainable products, willing to pay more for an environmentally friendly product, and cared about the environment were more likely to purchase this sustainable shoe prototype. The wear test with a small sample of four college students had split opinions on the comfort and wearability of the shoes. Still, all of them liked the concept of shoe materials and biodegradable shoes made from renewable materials.

Kaidong Song, Guoyue Xu, A. N. M. Tanvir et al.

Thermoelectric energy conversion is an attractive technology for generating electricity from waste heat and using electricity for solid-state cooling. However, conventional manufacturing processes for thermoelectric devices are costly and limited to simple device geometries. This work reports an extrusion printing method to fabricate high-performance thermoelectric materials with complex 3D architectures. By integrating high-throughput experimentation and Bayesian optimization (BO), our approach significantly accelerates the simultaneous search for the optimal ink formulation and printing parameters that deliver high thermoelectric performances while maintaining desired shape fidelity. A Gaussian process regression (GPR)-based machine learning model is employed to expeditiously predict thermoelectric power factor as a function of ink formulation and printing parameters. The printed bismuth antimony telluride (BiSbTe)-based thermoelectric materials under the optimized conditions exhibit an ultrahigh room temperature zT of 1.3, which is by far the highest in the printed thermoelectric materials. The machine learning-guided ink-based printing strategy can be highly generalizable to a wide range of functional materials and devices for broad technological applications.

Tomas Schuller, Maziyar Jalaal, Paola Fanzio et al.

The optimal design seeks the best possible solution(s) for a mechanical structure, device, or system, satisfying a series of requirements and leading to the best performance. In this work, optimized nozzle shapes have been designed for a wide range of polymer melts to be used in extrusion-based additive manufacturing, which aims to minimize pressure drop and allow greater flow control at large extrusion velocities. This is achieved with a twofold approach, combining a global optimization algorithm with computational fluid dynamics for optimizing a contraction geometry for viscoelastic fluids and validating these geometries experimentally. In the optimization process, variable coordinates for the nozzle's contraction section are defined, the objective function is selected, and the optimization algorithm is guided within manufacturing constraints. Comparisons of flow-type and streamline plots reveal that the nozzle shape significantly influences flow patterns. Depending on the rheological properties, the optimized solution either promotes shear or extensional flow, enhancing the material flow rate. Finally, experimental validation of the nozzle performance assessed the actual printing flow, the extrusion force and the overall print control. It is shown that optimizing the nozzle can significantly reduce backflow-related pressure drop, positively impacting total pressure drop (up to 41%) and reducing backflow effects. This work has real-world implications for the additive manufacturing industry, offering opportunities for increased printing speeds, enhanced productivity, and improved printing quality and reliability. Our research contributes to advancing extrusion-based printing processes technology, addressing industry demands and enhancing the field of additive manufacturing.

Nikolai Vogler, Kartik Goyal, Samuel V. Lemley et al.

We propose a novel computational approach to automatically analyze the physical process behind printing of early modern letterpress books via clustering the running titles found at the top of their pages. Specifically, we design and compare custom neural and feature-based kernels for computing pairwise visual similarity of a scanned document's running titles and cluster the titles in order to track any deviations from the expected pattern of a book's printing. Unlike body text which must be reset for every page, the running titles are one of the static type elements in a skeleton forme i.e. the frame used to print each side of a sheet of paper, and were often re-used during a book's printing. To evaluate the effectiveness of our approach, we manually annotate the running title clusters on about 1600 pages across 8 early modern books of varying size and formats. Our method can detect potential deviation from the expected patterns of such skeleton formes, which helps bibliographers understand the phenomena associated with a text's transmission, such as censorship. We also validate our results against a manual bibliographic analysis of a counterfeit early edition of Thomas Hobbes' Leviathan (1651).

Chandrasekaran P., Saminathan Ratnapandian

Increasing eco-consciousness among consumers is creating an expanding niche market for textiles coloured using natural dyes. Natural dyes are derived from different parts of plants, animals (insects and invertebrates) and minerals. Although plant sources are common, a growing global population makes them compete with food crops. Hence, there is a need to investigate alternate avenues for procuring natural dyes. This research examined the feasibility of utilizing extractions of sawdust, a waste product of the wood furniture industry, as a natural colorant. Sawdust is an inevitable waste generated during the conversion of wood into consumer products such as furniture (tables, chairs, etc.), doors and windows. Sawdust, generated in significant amounts by timber mills, may be used in chipboard manufacture. However, the furniture industry disposes of sawdust as fuel or sometimes as communal waste. In this study, segregated sawdust of the most common woods was collected from Ethiopian furniture houses in Addis Ababa and Bahir Dar. Dyeing was attempted on cotton and wool fabrics using individual aqueous extractions. Different shades were obtained only on wool by simultaneous mordanting with mordants, such as copper sulphate, ferrous sulphate and potassium dichromate, using the exhaust dyeing method. Acceptable fastness to light, perspiration, rubbing and washing, as evaluated according to the relevant ISO standards, was obtained. It may be concluded that sawdust is a viable secondary source of natural dyes for textile coloration in Ethiopia and elsewhere.

Gourab Ghosh, Sudeshna Saha, Sundipan Bhowmick

Crotalaria juncea bast fibers a novel cellulose rich material is valorized by producing cellulose nanocrystals (CNCs) which gained much attention due to its unique properties. CNCs obtained during this study consisted of two steps: pretreatment of C. juncea fibers to obtain chemically purified cellulose followed by sulfuric acid hydrolysis. Efficacy of two different pretreatment methods chlor-alkali method (pre-treatment-I) and ultra sound assisted chlorine free alkaline peroxide (pre-treatment-II) methods was examined for CNC preparation. Pre-treatment-I was found to be more effective yielding higher crystallinity and higher surface sulfate ester groups containing CNCs compared to CNCs obtained using pre-treatment-II. Moreover the cellulose structure was altered with more pure cellulose-I structure obtained from pre-treatment-I. The process conditions of pre-treatment – I was optimized for CNC preparation. The acid concentration of 80%(w/v) was found to be optimized to produce CNCs with~43% yield, 80.9% crystallinity index having a rod-like structure (Length −120 ± 26 nm and diameter − 25 ± 5.5 nm). The surface charge density of the optimized CNC was found to be 0.34 meqv/g and a zeta potential −27.7 mV was recorded emphasizing stable dispersion.

Leonid Losev, Vladimir Pazyuk, Alexey Gladyshev et al.

Gas-filled hollow-core fibers are a convenient tool for laser pulse compression down to a few-cycle duration. The development of compact, efficient and high quality compression schemes for laser pulses of relatively low μJ-level energies is of particular interest. In this work, temporal pulse compression based on nonlinear spectral broadening in a xenon-filled revolver fiber followed by a chirped mirror system is investigated. A 250 fs pulse at a central wavelength of 1.03 μm is compressed to 13.3 fs when the xenon pressure was tuned to provide zero group velocity dispersion near 1.03 μm. The energies of input and compressed pulses are 3.8 and 2.7 μJ, respectively. The compression quality factor of 1.8 is achieved.

Samantha Mora, Nicola M. Pugno, Diego Misseroni

High-precision 3D printing technology opens to almost endless opportunities to design complex shapes present in tailored architected materials. The scope of this work is to review the latest studies regarding 3D printed lattice structures that involve the use of photopolymers fabricated by Material Jetting (MJ), with a focus on the widely used Polyjet and MultiJet techniques. The main aspects governing this printing process are introduced to determine their influence during the fabrication of 3D printed lattices. Performed experimental studies, considered assumptions, and constitutive models for the respective numerical simulations are analyzed. Furthermore, an overview of the latest extensively studied 3D printed architected lattice materials is exposed by emphasizing their achieved mechanical performances through the use of Ashby plots. Then, we highlight the advantages, limitations, and challenges of the material jetting technology to manufacture tunable architected materials for innovative devices, oriented to several engineering applications. Finally, possible approaches for future works and gaps to be covered by further research are indicated, including cost and environmental-related issues.

Pratikhya Badanayak, Jyoti V. Vastrad, Seiko Jose

An attempt was made in this reported work to develop a protective kit for the cotton harvesters. With the assistance of a questionnaire, the health problems faced by the harvesters have been identified. Based on the survey, harvesters have been shown to suffer from frequent headaches, heat sensation, nose blockage, asthma, back pain, cracks in fingers, and heels. On this background information, a suitable functional protective kit/equipment (PPE) was developed, consisting of an apron with attached headgear, mask, glove, and goggles. The cotton harvesters were directed to use this kit regularly for a period of two months following the primary hygienic strategy. The post-use health issues were assessed using the same scheduled questionnaire. It is observed that the protective kit significantly reduced the everyday difficulties and enhanced the working efficiency of the harvesters.

Belgacem Keraani, Mahjoub Jabli, Mohamed Hamdaoui et al.

The comprehension of capillarity phenomenon is important in chemical, printing, and textile dyeing. The current paper provides an insight into the diffusion of direct dyes into cellulosic materials with regard to the change of fabric characteristics, dye structure, and bath composition. First, an experimental device was developed and series of experiments were carried out using cotton as textile fabric model and direct dyes (Direct Orange 39, Direct Red 79, and Direct Red 80) as wicking liquids. Data were analyzed based on the evolution of diffusion rate [D (cm2/s)] versus C/C0. Results exhibited that the capillary ascension of dyes depends on weft count, weave structure, yarn type, angle contact, wet agent, dye structure, and dye concentration. The D (cm2/s) values were much higher than for twisted yarn. The tortuosity lowered the diffusion of the dye along with fabrics. The rate of water transport increased with weft count and it became more important when the structure of fabric is more tightened. Both inter-yarn space and vertical position of the fabric limited the ascension of the liquid. In brief, along this study, we demonstrated that the proposed apparatus could provide a potential evaluation of wicking phenomenon along with textile materials.

Ali Sadeghianmaryan, Dara Zarbaf, Majid Montazer et al.

This study proposes a green and easy route for synthesizing clay/silver nanocomposite on denim fabric which can instantaneously discolor the garment and produce antibacterial effects during a one-step process with minimal toxicity to humans. Synthesis of organo-Montmorillonite/silver nanocomposite was carried out by reducing silver nitrate to nanosilver in the presence of a reducing agent and its attachment to opened layers of clay particles throughout a one-step process. Colorimetric properties were examined using L*a*b* values to understand the changes in denim color after the action of organo-montmorillonite (O-MMt) and nanosilver, which confirmed the dye removal action of clay/silver nanocomposite. UV-visible data proved the successful synthesis of nanosilver in addition to the indigo dye removal from the remaining effluent by exhibiting no peaks at 406 nm and 601.2 nm. SEM and TEM images depicted the shape and position of opened O-MMt layers, silver nanoparticles, and O-MMt/silver nanocomposites, verified by EDX, XRD, and FTIR data. Antibacterial examination showed noticeable results with maximum effectiveness of 100% against the growth of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria with acceptable cell viability of 94% with no detectable changes in cell shape and size.

Jayaprakash Sridhar, Ravindran Gobinath, Mehmet Serkan Kırgız

Synthetic fibers are normally used as reinforcing material to strengthen the concrete. Natural fibers have been considered as the most sustainable alternative for synthetic fibers in both cost and sustainability point of view. In this study, mechanical characteristics of pre-treated bamboo and jute fiber-reinforced concrete (FRC) composites have been evaluated. The performance of treated natural fibers in the enhancement of strength of concrete has been examined. Fibers were added in the percentage proportions of 0.5, 1, 1.5, 2, and 2.5 by the weight of cement in the concrete matrix. The compressive and flexural strength of fiber-reinforced concrete has been experimentally verified. The test results show that maximum compressive strength was obtained as 26.4 MPa and 26.1 MPa for concrete with 1.5% bamboo and 2% jute fibers, respectively, at 28 days of curing. Similarly, maximum flexural strength was obtained as 6.36 MPa and 6.1 MPa for concrete with 1.5% bamboo and 2% jute fibers, respectively, at 28 days of curing. Based on the maximum compressive strength and flexural strength, optimum dosage of treated bamboo and jute fiber has been identified as 1.5% and 2%, respectively. SEM analysis reveals that there is a good bonding between fibers and concrete matrix, and breaking of fibers is due to pulling load and debonding.

Ibtissem Ounifi, Youssef Guesmi, Claudia Ursino et al.

The present study highlights the influence of support and monomer properties on the performance of thin-film composite (TFC) membranes. For this purpose, a series of polyamide-cellulose acetate thin-film composite nanofiltration (TFC-NF) membranes were prepared by interfacial polymerization technique using cellulose acetate (CA) membrane as support and the monomer of cyclohexane-1,3,5 tricarbonylchloride (HTC) as an organic phase. The effect of the cellulose acetate concentration on the pore size of the membrane support was investigated using 15%, 16.5%, 18%, 19.5%, and 21.5% of cellulose acetate. m-phenylenediamine (MPD), piperazidine (PIP), and 1,3- cyclohexanebis (methylamine) (CHMA) were studied as monomers. Results displayed that PIP/HTC membrane is more hydrophilic and has more intense granular and convex structure with rougher surface compared to the other prepared membranes. The water flow and the porosity depended on the cellulose acetate concentration. The decrease in porosity complied well with permeability, contact angle, and SEM analysis. The membrane performances were evaluated for the retention of NaCl, CaCl2, and Na2SO4 retention. Comparing the Na2SO4 rejection with CaCl2 and NaCl, the former is higher than the latter.