• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.7
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• pp.952-961
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• 2013

This study optimizes a suitable dyeing method for polylactic acid (PLA) fabrics using disperse dyes. For this, disperse red 60 (DR 60), disperse blue 56 (DB 56), and disperse yellow 54 (DY 54) were used and dyed on PLA fabrics dependent of dyeing temperature and time. The fastness of PLA fabrics dyed with three disperse dyes were evaluated; in addition, dye exhaustion, color strength (K/S value), and colorimetric properties of PLA fabrics were compared with PET fabrics. The experiments indicated optimum dyeability of PLA fabrics with disperse dyes. The dyeing temperature was $90^{\circ}C$ for every dye and the dyeing time were 20 min, 60 min, and 40 min for DR 60, DB 56, DY 54, respectively. PLA fabrics had good color fastness to washing, dry cleaning fastness, hot pressing fastness, rub fastness, and perspiration fastness by DR 60, DB 56, and DY 54. The dye exhaustion of PLA fabrics were lower than PET fabrics; however, K/S values were higher than PET fabrics.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.446-451
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• 2002

Zirconia/alumina mixture powder was spray-dried various degree of dispersion, type of dispersants and powder content in the slurry. The quality of the granule was determined by observation of the granule shapes after spray drying and fracture of intergranular boundaries during pressing. Defect-free granules were obtained from the powders that formed weak flocs in the slurry. The granules, spray-dried from the slurry containing 32.5 vol% powder mixture and PVP as binder, were fractured completely during shaping and the sintered specimens showed a density of 99.7% and a flexural strength of 850 MPa.

• Journal of the Korean Ceramic Society
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• v.38 no.5
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• pp.418-423
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• 2001

16 mole%의 CeO$_2$가 고용된 Ce-TZP 소결체 사이에 140~240$mu extrm{m}$ 두께의 Ce-TZP-5~30 vol% $Al_2$O$_3$중간층이 삽입된 층상복합체를 분말건식가압성형법에 의해 제조하였다. 소결온도는 $Al_2$O$_3$가 5~30 vol.% 첨가될 때 90% 이상의 소결밀도를 얻을 수 있도록 1$600^{\circ}C$로 정하였다. 이러한 3층 복합체에서 바깥의 Ce-TZP 지역에서의 파괴 형태는 입내파괴를 보여주었지만 $Al_2$O$_3$가 함유된 중간층에서는 입계파괴가 전이되면서 인성증가를 보여주었다. 이러한 층상 복합체의 경우 중간 층에 들어가는 Ce-TZP 중의 $Al_2$O$_3$함량이 30 vol.% 정도에 이르면 층간의 서로 다른 소결밀도 및 수축율, 열팽창계수 때문에 층간 소결 결함이 생겨 층간에서 균열의 전파가 큰 영향을 받음을 알 수 있었다. 반면 중간층의 $Al_2$O$_3$함량이 적을 경우 층간 결함이 생기지 않아 층간에서 균열의 전파가 별 영향을 받지 않음을 알 수 있었다.

• Journal of Powder Materials
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• v.25 no.6
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• pp.501-506
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• 2018

With the recent remarkable improvements in the average speeds of contemporary trains, a necessity has arisen for the development of new friction modifiers to improve adhesion characteristics at the wheel-rail interface. The friction modifier must be designed to reduce slippage or sliding of the trains' wheels on the rails under conditions of rapid acceleration or braking without excessive rolling contact wear. In this study, a novel composite material consisting of metal, ceramic, and polymer is proposed as a friction modifier to improve adhesion between wheels and rails. A blend of Al-6Cu-0.5Mg metallic powder, $Al_2O_3$ ceramic powder, and Bakelite-based polymer in various weight-fractions is hot-pressed at $150^{\circ}C$ to form a bulk composite material. Variation in the adhesion coefficient is evaluated using a high-speed wheel-rail friction tester, with and without application of the composite friction modifier, under both dry and wet conditions. The effect of varying the weighting fractions of metal and ceramic friction powders is detailed in the paper.

• Journal of the Korean Wood Science and Technology
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• v.16 no.4
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• pp.48-53
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• 1988

This study was carried out to investigate the effects of pressing time and spreading amount, moisture content, gap-distance with butt to butt joint and adhesives on bonding strength in manufacturing the laminated wood with Pitch pine (Pinus rigida). The results obtained were as follows: 1) The pressing time of 12 hours, 10 kilogram per square centimeter of pressure and 200 gram per square meter of spreading amount were required to reach over 50 kilogram per square centimeter (block shear strength) in manufacturing the laminated wood by aqueous vinyl urethane adhesive. 2) The bonding strength decreased with the increase of moisture content of wood. The block shear strength, however, showed over 100 kilogram per square centimeter when the strength test was carried out after air-drying the laminated wood in high moisture content (30-70%). 3) Regardless of direction of load, every flexural property decreased with the increase of gap-distance with butt to butt joint. However, little of every flexural property was changed at 0.5 millimeter of joint-gap distance. The flexural property of vertically laminated wood (perpendicular to glue line to load direction: 1) showed more than that of horizontally laminated wood (parallel to glue line to load direction: //). 4) Among five adhesives used at this experiment, the bonding strength of aqueous vinyl urethane adhesive was the highest in dry bond and wet tests.

• Journal of the Korean Ceramic Society
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• v.25 no.3
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• pp.225-230
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• 1988

The strength and thermal shock resistance of $Al_2O_3-ZrO_2$ composites have been studied. The tetragonal $ZrO_2$ powder containing 1 mol.% $Y_2O_3$ and monoclinic $ZrO_2$ powder were prepared by coprecipitation method and subsequently mixed with $Al_2O_3$ powder and granulated by sieving. Duplex composites were prepared by dry mixing matrix agglomerate with 15 to 30 vol.% of dispersion agglomerate, followed by pressing and sintering at 1$600^{\circ}C$ for1 hr. These $Al_2O_3-ZrO_2$ 2 composites having heterogeneous structure showed improved thermal shock behaviors because of the microcracking and pores in dispersed granules, and compressive stresses around dispersed granules resulting from $ZrO_2$ transformation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.4
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• pp.34-42
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• 2008

Generally, paper multilayering was performed before wet pressing process. However, sheets whose characteristics are different could be put together at the dry state by adhesives for the specialty paper products. In this paper, potential adhesives such as PVAc, oxidised starch, latex, and PVA were chosen and multilayering of several sheets was performed in laboratory scale. The effects of base paper properties and the composition of adhesives on the physical properties of multilayering paper were investigated. Physical properties such as bonding strength and stiffness were measured. For the practical reasons, mill trial was also executed. According to the result of laboratory tests and mill trial test, the physical properties of multilayered paper were greatly affected by the composition of adhesives and it was found that PVAc showed the best performance in all its aspects among four adhesives. Oxidised starch had an advantage of high stiffness and PVA gave high bonding strength to the multilayered paper. And it was also found that the properties of base paper showed the great influences not only on multilayering process, but also on the physical properties of the multilayered paper.

• Korean Journal of Food Science and Technology
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• v.9 no.3
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• pp.220-224
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• 1977

To dry the sweet potato efficiently, the fresh sweet potato was soaked in hot water of $60{\sim}65^{\circ}C$ for $1{\sim}1.5hrs.$ and cut into 0.5cm thick slices, followed by pressing at $40kg/cm^2$. This predehydrated cake contained $43{\sim}55%$ moisture and can be dried further either by sundrying or hot air drying. Using the dried sweet potato, ethanol was produced (ethanol production; 433l/M/T) by the conventional alcohol fermentation. The extracts as a by-product ($340{\sim}450ml$ per Kg of fresh potato) contained 5% total sugar and may be used directly for alcohol fermentation without further concentration.

• Design & Manufacturing
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• v.14 no.3
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• pp.50-56
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• 2020

Ceramic tile is widely used as a floor or interior decoration of buildings. The main processes are raw material blending, molding, drying, firing, etc., and since dimensional and quality stability are very important, they are generally molded by a dry press method. In ceramic tile molds, there is a liner that can be easily replaced in case of wear. The liner is constantly abrasion due to a continuous pressing process during tile forming, and it is required to be replaced every certain period. Even in the liner, use a wear-resistant fitting material only in areas where wear is concentrated. However, there was a risk that the fitting material was applied to large-sized tile molding due to problems such as damage to the molding machine and decrease in productivity when detached during the actual tile molding process due to weak fitting strength with the liner. Therefore, in this study, thermal-structural analysis for fitting tolerance analysis and structural analysis for fitting force analysis were performed for the shrink fit process of the fitting material.

• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.253-264
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• 2019

This study characterized the chemical compounds in tannin from mangium (Acacia mangium) bark extract and determined the physical-mechanical properties of glued laminated timber (glulam) made from sengon (Falcataria moluccana), jabon (Anthocephalus cadamba), and mangium wood. The adhesives used to prepare the glulam were based on mangium tannin and phenol resorcinol formaldehyde resin. Five-layer glulam beams measuring $5cm{\times}6cm{\times}120cm$ in thickness, width, and length, respectively, were made with a glue spread of $280g/m^2$ for each glue line, cold pressing at $10.5kgf/cm^2$ for 4 h and clamping for 20 h. Condensed mangium tannin consisted of 49.08% phenolic compounds with an average molecular weight of 4745. The degree of crystallinity was 14.8%. The Stiasny number was 47.22%. The density and the moisture content of the glulams differed from those of the corresponding solid woods with mangium having the lowest moisture content (9.58%) and the highest density ($0.66g/cm^3$). The modulus of rupture for all glulam beams met the JAS 234-2003 standard but the modulus of elasticity and the shear strength values did not. Glulam beams made with tannin had high delamination under dry and wet conditions, but glulam made from sengon and jabon wood met the standard's requirements. All glulam beams had low formaldehyde emissions and were classified as $F^{****}$ for formaldehyde emissions according to the JAS 234 (2003) standard.