• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.78-85
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• 2006

In textile industries, waste effluent containing zinc is generated during the manufacture of rayon yarn from the wood pulp or cotton linters. Due to the strict environmental regulations and the presence of toxic metallic and other constituents, the discharge of industrial effluents in the sewage or disposal of solid sludge as landfill is restricted. Before recycling of zinc as zinc sulphate solution to the spinning-bath of the rayon manufacturing plant the zinc sulphate solution must be free from calcium, which is deleterious to the process as gypsum precipitates with the increase in concentration and forms scale in the bath. In the present work an attempt has been made to develop a process following solvent extraction technique using thiophosphinic extractants, Cyanex 272 and 302 modified with isodecanol and diluted in kerosene to recover zinc from rayon effluent. Various process parameters viz. extraction of zinc from different concentration of solution, distribution ratio, selective extraction, O/A ratio on extraction and stripping from the loaded organic, complex formation in the organic phase etc. have been studied to see the feasibility of the process. The extractant Cyanex 302 has been found selective for the recovery of 99.99% of zinc from the effluent above equilibrium pH 3.4 maintaining the O/A ratio of 1/30 leaving all the calcium in the raffinate. It selectively extracted zinc in the form of complex $[R_{2}Zn.3RH]_{org}$ and retained all the calcium in the aqueous raffinate. The zinc from the loaded Cyanex 302 can be stripped with 10% sulphuric acid at even O/A ratio of 10 without affecting the stripping efficiency. The stripped solution thus obtained could be recycled in the spinning bath of the rayon plant. The raffinate obtained after the recovery of zinc could be disposed safely without affacting environment.

• Composites Research
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• v.29 no.4
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• pp.145-150
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• 2016

Polyvinylidene fluoride (PVDF) as a representative polymer with the piezoelectric property has been studied since the 1960s. Crystalline structure of poly(vinylidene fluoride) polymer is composed of five different crystal structure of the polymer as a semi-crystalline. Among the various crystal structures, ${\beta}-type$ crystal exhibits a piezoelectricity because the permanent dipoles are aligned in one direction. Generally ${\beta}-form$ crystal structure can be obtained through the transformation of the ${\alpha}-form$ crystal structure by the stretching and it can increase the amount through the after treatment as poling process after stretching. ${\beta}-form$ crystal structure the PVDF fibers produced by wet spinning is formed through a diffusion mechanism of a polar solvent in the coagulation bath. However, it has a disadvantage that the diffusion path of the solvent remains as pores in the fiber because the fiber solidification occurs simultaneously with the diffusion of the polar solvent. These pores play a role in reducing effect of poling process owing to effect of disturbances acting on the polarization by the electric field. In this work, the drying method using the microwave was introduced to remove more effectively the residual solvent and the pore within PVDF fibers produced through wet-spinning process and piezoelectric PVDF fibers was produced by transformation of the remaining ${\alpha}$ form crystal structure into ${\beta}-crystal$ structure through the stretching process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.943-948
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• 1996

In this paper. we will discuss in making large size cylindrical shells with multithickness wall sections such as straight, stepped, tapered sides. These shells are constructed of type 6061 O temper aluminum starting with a blanking size of 877 mm plate. Its diameter to length ratio of 1 to 2.78 and a 36.7％ wall reduction is achieved by our continuous deep drawing process. This process required no in-process annealing. But after cold working, these shells is performed heat treatment to T6 condition. These shells are used for the making of seamless LPG pressure vessels after the spinning process. This process is composed of deep drawing, reverse redrawing, drawing-ironing and several ironing processes. In the verification of forming process design, we used DEFORM code.

• Textile Coloration and Finishing
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• v.32 no.2
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• pp.111-120
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• 2020

In this study, lignin/chlorinated poly(vinyl chloride)(CPVC) blended fibers have been produced for the development of low-cost carbon fiber. Carbon fiber manufacturing was accomplished through stabilization and carbonization process. The lignin/CPVC blended fibers were prepared by wet spinning method. Dimethylacetamid e(DMAc) and cychlohexanone in a ratio of 5:1(wt%) was employed as co-solvent. The ratio of lignin/CPVC was prepared at 0/10, 1/9, 2/8, 3/7, 4/6, and 5/5(wt%). The spinning solution was extruded at a rate of 0.1 to 0.4ml/min according to the blending ratio. The speed of the rollers was the same for all ratios(draw ratio=1). Analysis of fiber cross-section by scanning eletron microscopy(SEM) showed that as the lignin ratio increased in the same coagulation bath and distilled water, the pore size of the spinning fiber decreased. Therefore, the highest tensile strength of the blending fibers was 6.3±1.2MPa at the 5/5 ratio. The carbon fiber also showed the best tensile strength of 120.78±2.43MPa at 5/5 ratio.

• Membrane and Water Treatment
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• v.1 no.3
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• pp.215-230
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• 2010

Poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP, hollow fiber membranes were prepared by the dry/wet spinning technique using different polyethylene glycol (PEG) concentrations as non-solvent additive in the dope solution. Two different PEG concentrations (3 and 5 wt.%). The morphology and structural characteristics of the hollow fiber membranes were studied by means of optical microscopy, scanning electron microscopy, atomic force microscopy (AFM) and void volume fraction. The experimental permeate flux and the salt (NaCl) rejection factor were determined using direct contact membrane distillation (DCMD) process. An increase of the PEG content in the spinning solution resulted in a faster coagulation of the PVDF-HFP copolymer and a transition of the cross-section internal layer structure from a sponge-type structure to a finger-type structure. Pore size, nodule size and roughness parameters of both the internal and external hollow fiber surfaces were determined by AFM. It was observed that both the pore size and roughness of the internal surface of the hollow fibers enhanced with increasing the PEG concentration, whereas no change was observed at the outer surface. The void volume fraction increased with the increase of the PEG content in the spinning solution resulting in a higher DCMD flux and a smaller salt rejection factor.

• Fibers and Polymers
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• v.7 no.3
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• pp.317-322
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• 2006

Reduction of yam hairiness by nozzles in ring spinning and winding is a new approach. Simulation of the airflow pattern inside the nozzles provides useful information about actual mechanism of hairiness reduction. The swirling air current inside the nozzles is capable of wrapping the protruding hairs around the yam body, thereby reducing yam hairiness. Since production rate of winding is very high and the process itself increases yarn hairiness any method to reduce the hairiness of yarns at this stage is a novel approach. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern inside the nozzles using Fluent 6.1 software. In this study, both S- and Z-type nozzles having an axial angle of 500 and diameter of 2.2 mm were used for simulation studies. To create a swirling effect, four air holes of 0.4 mm diameter are made tangential to the inner walls of the nozzles. S- and Z-twisted yams of 30 tex were spun with and without nozzles and were tested for hairiness, tensile and evenness properties. The total number of hairs equal to or exceeding 3 mm (i.e. the S3 values) for yam spun with nozzle is nearly 49-51 % less than that of ring yams in case of nozzle-ring spinning, and 15 % less in case of nozzle-winding, while both the yarn types show little difference in evenness and tensile properties. Upward airflow gives best results in terms of hairiness reduction for nozzle-ring and nozzle wound yams compared to ring yarns. Yarn passing through the centre of the nozzle shows maximum reduction in S3 values.

• The Research Journal of the Costume Culture
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• v.24 no.4
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• pp.471-482
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• 2016

This study investigated the characteristics of cotton production of Damyang-gun & Hwasun-gun, Yeongsan River compared with that of Gurye-gun, Seomjingang River in modern times. To do this, research method was both literature and fieldwork research, results were as follows. First, as for cotton fiber cultivation in Damyang-gun & Hwasun-gun, Chinese cotton (在來綿) has been cultivated during Japanese Colonial era unlike Gurye-gun. Especially, Yellow cotton (黃綿) has been cultivated in Hwasungun. Second, as for spinning in Damyang-gun, Hwasun-gun and Gurye-gun, some of cotton spinning process have been gradually changed to mechanization by market shop equipped with mechanized cotton gin and cotton whipping tool since Japanese colonial era. Third, the loom types also, like spinning tools, have been changed from the traditional Korean back-strap loom to the treadle loom in Damyang-gun, Hwasungun and Gurye-gun. Chemical dyeing with chemical dyestuff also has been done since Japanese Colonial era. Fourth, since the 1970s, the outputs of cotton production have been reduced in both Damyang-gun & Hwasun-gun. For Damyang-gun, this has been connected with bamboo craft since the Joseon Dynasty period. So, Damyang-gun has more concentrated on bamboo craft than cotton production. For Hwasun-gun, since Japanese Colonial era, sericulture has been very important. So, Hwasun-gun also has more concentrated on sericulture than cotton production. The main reason to discontinue cotton production in Damyang-gun, Hwasun-gun and Gurye-gun was related to the local choice like economic added value.

• Macromolecular Research
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• v.17 no.6
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• pp.378-387
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• 2009

This research compared three methods for producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency. The three methods used to mix antimicrobial agents based on silver nano particles with PP were as follows: 1) mixing of PP powder and inorganic nanocomposite filler with the appropriate concentration using a twin-screw extruder and preparing granules, 2) method 1 with a singlerather than twin-screw extruder, and 3) producing the masterbatch by a twin-screw extruder and blending it with PP in the melt spinning process. All pure polypropylene samples and other combined samples had an acceptable spinnability at the spinning temperature of $240^{\circ}C$ and take-up speed of 2,000 m/min. After producing as-spun filament yarns by a pilot plant, melt spinning machine, the samples were drawn, textured and finally weft knitted. The physical and structural properties (e.g., linear density, tenacity, breaking elongation, initial modulus, rupture work, shrinkage and crystallinity) of the as-spun and drawn yarns with constant and variable draw ratios (the variable draw ratio was used to gain a constant breaking elongation of 50%) were investigated and compared, while DSC, SEM and FTIR techniques were used to characterize the samples. Finally, the antibacterial efficiency of the knitted samples was evaluated. The experimental results revealed that the crystallinity reduction of the as-spun yarn obtained from method 1 (5%) was more than that of method 2 (3%), while the crystallinity of the modified as-spun yarns obtained with method 3 remained unchanged compared to pure yarn. However, the drawing procedure compensated for this difference. By applying methods 2 and 3, the drawing generally improved the tenacity and modulus of the modified fibers, whereas method 1 degraded the constant draw ratio. Although the biostatic efficiency of the nanocomposite yarns was excellent with all three methods, the modified fabrics obtained from methods 1 and 2 showed a higher bioactivity.

• Fashion & Textile Research Journal
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• v.10 no.6
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• pp.1058-1063
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• 2008

The use of clothes dryers is increasing in Korea and throughout Asia, because of preference for the drum type washer dryer. Clothes dryers consume more energy than almost any other home appliance. This paper suggests efficient ways for drying laundry with condensing clothes drier. We dried cotton fabrics with the condensing clothes dryers and observed the energy input, temperature and RH of the dryer during the drying process. In the early stages of drying process, the air temperature inside the clothes dryer decreased and the RH and the drying time increased as the weight of fabrics increased. We found that it was important to consider the total weight of the fabrics that included heat-sensitive fibers. It took more than half the drying time and the energy input for a 2.5 kg load that it did for a 5 kg load. Therefore, drying larger one load was more efficient than divided smaller loads, because increasing the weight of the fabrics reduced the energy input per kg of drying clothes. The lower the initial moisture regains of the fabrics were, the lower the energy input and the drying time were. The energy input for spinning after washing was much less than that for drying in the dryer. Consequently, it is more efficient to reduce the moisture content of the clothes by lengthening the spinning time of the washer to reduce the energy consumption and the drying time. During the drying process opening the door twice for 30 seconds each time lowered the air temperature and the RH of the dryer, but did not affect the moisture regain of the fabrics, the drying time, and the energy input.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.133-139
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• 2022

This study deals with the formation of Jongyeonbangjeok's Gwangju Factory in the 1930's to 80's, and the findings are shown below: In the period of formation, the factory was rectangular-shaped from north to south, and the structure was located at the center of the site, and in the east of it, there was a dormitory connected from south to north. The building was arranged with an open area on the south. In the east of the site where company houses were located, same-sized structures were arranged along the axis.In the period of change, the factory was restored about the damage from the Korean War, and it went through the process of division into two companies. As a result, the factory in the center of the site was divided into left and right ones, and the dormitory and the group of company houses were, too, divided into two, so division was made largely into southern and northern parts. In the period of stabilization, along with factory extension in each of the companies, welfare for factory workers was expanded by building more houses or opening sport facilities. After the 1980's, too, the existing factories were either extended or remodeled according to the induction of equipment, and some showed changes in their functions due to a fire or such.