• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.39-45
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• 2014

Various approaches have been tried to reduce the emission of carbon dioxide in paper industry. One of important approaches is to use PCC manufactured from emission gas as a filler. However, it was recognized that PCC is inferior to other fillers in the paper strength properties of view. Therefore, pretreatment of PCC with pulp powder was tried to mitigate the strength reduction of paper. Pretreatment of PCC with pulp powder improved the bulk(7.4~12.9%) and air permeability(24.8~42.98%), but there is no significant change in opacity. Tensile index, burst index and stiffness were decreased by the use of pretreated PCC with pulp powder. Anionic and cationic PAM were used as a additive for PCC pretreatment in order to improve strength properties. There was no significant change in bulk in all kinds of PAM used in this study. Most strength properties were improved by the pretreatment of PCC with the anionic and cationic PAM and pulp powder, although the opacity and stiffness were more or less decreased.

• Membrane Journal
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• v.17 no.2
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• pp.140-145
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• 2007

In this study, 3-(trihydroxysilyl)-1-propanesulfonic acid (THS-PSA) was added to poly(vinyl alcohol) (PVA) membranes crosslinked with poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA) to improve the separation characteristics toward water vapors in the air. The prepared membranes varying both PSSA_MA and THS-PSA amounts were also synthesized at different cross linking temperatures. Then, in order to investigate the separation characteristics of the resulting membranes, the dynamic vapor sorption (DVS) and vapor permeation experiments were carried out. The increase of cross-linking temperature showed longer time to reach the equilibrium sorption state from the dynamic vapor sorption experiments. PVA/PSSA_MA (3%)/THA-PSA(7%) prepared at $120^{\circ}C$ gave the highest permeability of 480 barrer at $35^{\circ}C$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.2
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• pp.47-54
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• 1998

Refining is one of the most important processes of fiber treatment that provides optical and physical properties of final paper products. The evaluation method of refining progress is usually freeness (CSF) or wetness (SR) test because of its rapidity and convenience. However, there are some deficiencies in using freeness or wetness test to evaluate pulp fibers accurately because its results are more influenced by fines contents than extent of fibers treatment. The objective of this study is to show the deficiency of wetness in evaluating the refining process. For this, beating is done by varying the beating load. Handsheets are made after beating until 25 and $32^{\circ}C$ SR, and then paper properties are measured. Refined fibers are analyzed by fiber length, fines contents, curl, kink, WRV, and zero-span tensile strength. The results show that longer beating time is required to reach the same wetness at lower beating load. There are differences in the average fiber length, distribution curve of fiber length, fines contents, curl, kink, WRV of long fiber fraction, drainage time, and zero-span tensile strength of rewetted sample at different beating load. At the low beating load in the same wetness, apparent density, breaking length, burst strength, and tear strength are higher, while opacity and air permeability are lower than those of the high beating load. Using Page s equation, which shows the relationship among tensile strength, intrinsic fiber strength, and interfiber bonding strength, interfiber bonding strength is calculated and analyzed to explain final paper properties. At $25^{\circ}C$ SR, interfiber bonding strength is only slightly higher at 2.5kgf beating load, while the intrinsic fiber strength is substantially higher. At $32^{\circ}C$ SR, intrinsic fiber strength is a little bit higher at 2.5kgf beating load, and interfiber bonding strength is remarkably higher than those of 5.6kgf beating load. These results can be used to explain the different properties of the final paper at selected beating loads.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.461-467
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• 1998

Two hundred grams of fresh jujubes at whitish green maturity was packaged in the film bags of different gas permeabilities and stored at 0 and $5^{\circ}C$. Through the storage package atmosphere and jujube quality were monitored. Package of $30\;{\mu}m\;CPP$ film resulted in anaerobic conditions of $O_2$ content below 1% and $CO_2$ content above 15%, and caused off-flavor at both temperatures within 4 weeks. Package of $60\;{\mu}m\;LDPE$ film also showed potential risk of anaerobic condition development within 5 weeks, because of high $CO_2$ and/or low $O_2$ concentration at 0 and $5^{\circ}C$. Microperforated film packages could preserve quality of jujubes for 10 and 7 weeks at 0 and $5^{\circ}C$, respectively, which were significantly longer than shelf lives for perforated air pack and hermetically sealed packages.

• Journal of the Korea Furniture Society
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• v.22 no.1
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• pp.63-71
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• 2011

Hanji has known for its high qualities for more than thousand years. Hanji is stronger, and has better durability, air permeability, flexibility, thermal insulation, soundproofs and UV absorbability. Therefore, developing industrial interior finishing materials using Hanji is replaced with the PVC (Poly-Vinyl Chloride) materials instead, it will be a new environment-friendly material and positively represents Korean brand marketing. The industrial inter-construction material is discomposed by heat or light because of material characteristics. As a result, it emits a lot of noxious substances. Hanji is essentially a neutral paper since it does not rely on any acidic chemicals of artificial bleaching methods. Hanji is also known as the living paper because of its close relation to nature. Therefore, I would like to suggest that Hanji made from alternative material as a chicken fiber. It will be a non-polluting interior finishing materials by making use of Hanji to a taste of Korean culture in the green industry around the world. Rather than PVC used commonly in construction material, kitchen and office furniture, interior materials in the subway, trains, or other vessels, credit cards, and ID cards, I created an interior construction material by using patented Hanji. This will be increased the value of usefulness in the environment-friendly green industry instead of PVC.

• Polymer(Korea)
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• v.34 no.6
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• pp.517-521
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• 2010

Microprous polyethylene (PE) membranes are widely used as lithium-ion battery separators. A separator having higher meltdown temperature than PE separator is still required for useful safety feature at a high temperature. To enhance meltdown temperature of PE separator, it was coated with polymers synthesized from bis-GMA derivatives by radical polymerization. Polymer was not formed when bis-GMA monomer having a high viscosity was used, while polymers were formed when bis-GMA derivatives having a low viscosity were used. When the separator was coated with polymer synthesized from reaction mixture containing proper amount of bis-GMA derivative, its meltdown temperature were increased up to $160^{\circ}C$ without reduction in the air permeability.

• Fashion & Textile Research Journal
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• v.20 no.2
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• pp.202-209
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• 2018

This study examined thermo-physiological responses according to the design change of construction site working clothes (control (C) working clothes; prototype (P) working clothes). We measured rectal temperature, skin temperature, micro-climate within the clothes and sweat rate. In the evaluation of physiological functionality, based on pattern improvement in working clothes, P working clothes showed significantly lower rectal temperatures, trunk and thigh skin temperatures than C working clothes. It is preferable that rectal temperature should be kept low during work that is not favorable to an increase in body temperature. P working clothes were more physiologically functional than C working clothes. In addition, P working clothes showed significantly lower temperatures in the trunk and thigh parts in a micro climate temperature. We could explain that the side seam zipper on the pants and the gusset on armpit parts create an air permeability effect of lowering the temperature of micro-climate. Aggressive ventilation through the slit of the garment is an important factor for the restoration of the physiological function of the worker at rest between work. Sweat rate showed a higher level in C working clothes than P working clothes. When working in a hot environment, workwear needs to be designed so that the worker is not exposed to thermal stress. Therefore, it was evaluated that the P work clothes used in this study alleviated the physiological burdens of heat.

• Journal of Fashion Business
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• v.21 no.4
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• pp.144-158
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• 2017

Fur garment has long been the conventional symbol for luxury, or conspicuous consumption. However, as fashion items began to diversify as part of overall fashion trend, fur items are now more about individual taste and style than just lavishness. Synthetic fur is especially emerging as a new promising fashion material, with a touch almost like natural fur at an affordable price. Along with the emergence of 'Vegan Fashion' trend, synthetic fur is establishing itself as a popular fashion textile. This study is an attempt to investigate subjective evaluation and physical properties of natural and synthetic furs, whose results will further serve as basic data in developing synthetic fur materials. Sensory and emotional evaluations are carried out on natural and artificial furs. For analysis, factors such as weight, thickness, air permeability, gloss and compressibility were surveyed to observe how they influence the physical properties. According to the subjective evaluation, natural and artificial fur samples do not differ in conspicuous ways in appearance. Experiments on physical properties, specifically warm/cool touch experiment, show that natural fur has a slightly higher warm sensation than artificial fur. Luster analysis by using a microscope revealed that there are subtle qualitative differences between natural and artificial fur. During the subjective evaluation, subjects found it hard to state distinct quantitative differences in luster. A survey as a means of assessing qualitative differences in gloss seems to be necessary to complement the evaluation. Results from this study will potentially serve as resources for diversification of fashion product designs using synthetic fur.

• Advances in concrete construction
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• v.2 no.2
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• pp.109-123
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• 2014

This paper presents chloride induced corrosion durability of reinforcing steel in geopolymer concretes containing different contents of sodium silicate ($Na_2SiO_3$) and molarities of NaOH solutions. Seven series of mixes are considered in this study. The first series is ordinary Portland cement (OPC) concrete and is considered as the control mix. The rest six series are geopolymer concretes containing 14 and 16 molar NaOH and $Na_2SiO_3$ to NaOH ratios of 2.5, 3.0 and 3.5. In each series three lollypop specimens of 100 mm in diameter and 200 mm in length, each having one 12 mm diameter steel bar are considered for chloride induced corrosion study. The specimens are subjected to cyclic wetting and drying regime for two months. In wet cycle the specimens are immersed in water containing 3.5% (by wt.) NaCl salt for 4 days, while in dry cycle the specimens are placed in open air for three days. The corrosion activity is monitored by measuring the copper/copper sulphate ($Cu/CuSO_4$) half-cell potential according to ASTM C-876. The chloride penetration depth and sorptivity of all seven concretes are also measured. Results show that the geopolymer concretes exhibited better corrosion resistance than OPC concrete. The higher the amount of $Na_2SiO_3$ and higher the concentration of NaOH solutions the better the corrosion resistance of geopolymer concrete is. Similar behaviour is also observed in sorptivity and chloride penetration depth measurements. Generally, the geopolymer concretes exhibited lower sorptivity and chloride penetration depth than that of OPC concrete. Correlation between the sorptivity and the chloride penetration of geopolymer concretes is established. Correlations are also established between 28 days compressive strength and sorptivity and between 28 days compressive strength and chloride penetration of geopolymer concretes.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.1-11
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• 2015

PURPOSES : This study set out to investigate the fundamental properties of alkali-activated concrete (AAC) using modified slag as the pavement maintenance material. METHODS: The material properties of modified slag based alkali-activated concrete (MSAAC) were analyzed and evaluated against those of alkali-activated slag concrete (AASC). Several mix formulations were considered, including one MSACC and four AASCs. The main variables considered in the study were slump, air content, compressive strength, rapid chloride permeability test, scaling resistance, freeze-thaw test, XRD, SEM, and EDS. RESULTS: MSAAC exhibits a compressive strength in excess of 21 MPa six hours after curing. Also, the charge passed of the MSACC was found to be less than 2000 coulombs after seven days and about 1000 coulombs after 28 days. The weight loss determined from a scaling test did not exceed $1kg/cm^2$ in the case of the MSACC, but that of the AASCs had already exceeded $1kg/cm^2$ at the 10th cycle. Based on the results of the freeze-thaw test, the relative dynamic modulus of every mix was found to be in excess of 90%. An energy dispersive spectroscopy(EDS) analysis found that the weight rate percentage of the calcium and aluminum in the MSAAC mix is twice that of the AASC mixes. CONCLUSIONS : It was found that the MSAAC mix exhibits significantly better performance than AASC mixes, based on various fundamental properties.