• 대한조선학회논문집
• /
• 제45권6호
• /
• pp.735-749
• /
• 2008

For the development of the original technique of structural safety assessment of Cargo Containment System(CCS) in membrane type LNG carriers, it is necessary to understand the characteristics of dynamic response behavior of CCS structure under sloshing impact pressure. In the previous study, the wet drop impact response analyses of CCS structure in membrane Mark III type LNG carriers were carried out by using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code, and were also validated through a series of wet drop experiments for the enhancement of more accurate shock response analysis technique. In this study, the characteristics of structural shock response behaviors of CCS structure were sufficiently figured out by careful examinations of the effects of specimen weight, drop height, incident angle, corrugation and stiffness of inner hull on its shock response behaviors. The shock response analysis of upward shooting fluid to inner hull was performed, and the reason of faster strain response than shock pressure one was also figured out.

• 한국식품저장유통학회지
• /
• 제10권2호
• /
• pp.187-191
• /
• 2003

검은버섯분말 3, 5, 7%를 첨가하여 국수를 제조한 후 품질을 분석해 련 결과 최고점도와 최종점도 및 노화도는 무처리보다 버섯첨가구에서 모두 낮은 값을 나타내었으며 첨가량이 증가할수록 낮아지는 경향을 나타내었다. 버섯분말첨가량이 증가함에 따라 수분흡수율은 약간 증가하였다. 색도는 버섯분말의 첨가량이 증가함에 따라 분말, 반죽, 국수등 모든 처리구에서 명도는 낮아졌으며, 적색도와 황색도는 증가하는 것으로 나타났다. 버섯국수 조리후 중량과 부피는 버섯분말 첨가량이 증가할수록 감소하였으며 국물의 탁도는 감소하였다. 조리면의 물성 측정 결과 버섯분말 첨가량이 증가함에 따라 경도와 부착성은 감소하였으며 응집성은 감소하였다. 조리한 국수의 관능검사 결과, 버섯분말 3∼5%첨가국수에서 높은 값을 나타내어 무첨가 국수보다 우수하였다.

• Environmental Analysis Health and Toxicology
• /
• 제25권3호
• /
• pp.229-240
• /
• 2010

During the last decade, perfluorinated compounds (PFCs) have gained more attention due to their toxicity and global distribution. The aim of this study was to examine the distribution and bioaccumulation of perfluorinated compounds (PFCs) in aquatic wildlife effected from a sewage treatment plant. The concentrations of 12 PFCs were determined in water, sediment and fish samples. PFOS were predominantly detected in both ambient environment and fish. In fish, the concentration of PFCs in blood was the highest (i.e., 112.47 ng/mL wet-wt. PFOS) in comparison to other tissues. However, PFOA and PFHpS were highly detected in gonad as 3.87 and 4.58 ng/g wet-wt., respectively. The bioconcentration factor (BCF) of PFCs was greatest in the blood > liver${\cong}$gonad > kidney > gill, and lowest in the muscle tissue. The BCFs of PFUnDA (39,000), PFDA (2,700) and PFOS (1,100) were rated as high values based on wet weight concentration. BCFs increased with increasing the length of the perfluoralkyl chain.

• 한국염색가공학회지
• /
• 제33권4호
• /
• pp.302-308
• /
• 2021

Air filters are being used in countless places from industrial sites to everyday life. The spread of the COVID-19 virus, which started in 2019, is disrupting people's daily lives, and the importance of air filters as a basic means to prevent the spread of these diseases is further highlighted. In this study, the purpose was to develop another type of air filter media with excellent barrier properties that can replace PP meltblown nonwoven fabrics widely used commercially due to its excellent electrostatic properties, differential pressure and filtration efficiency. Therefore, wet-laid nonwoven for air filters were manufactured using plexi-filaments formed through flash spinning and having various fiber diameter from hundreds of nanometers to tens of micrometers, and its applicability as an air-filter media was investigated compared to the meltblown nonwoven. As a result of the performance evaluation, it was found that the filtration efficiency and barrier performance at 0.3㎛ was superior to that of the meltblown nonwoven of the same weight, although the differential pressure was high due to morphological properties of the plexi-filament.

• 한국수소및신에너지학회논문집
• /
• 제28권2호
• /
• pp.129-136
• /
• 2017

Characteristics of $ZrO_2$ felt supported Cu/Zn catalysts have been investigated for the production of hydrogen via methanol steam reforming. Cu and Zn in different weight percent were loaded using wet impregnation over $ZrO_2$ felt support. The catalysts were characterized with BET and FE-SEM. The performance of these synthesized catalysts were investigated at SCR=1.5, $GHSV=2000h^{-1}$, temperature=$300{\sim}400^{\circ}C$, and pressure=2.5~19.5 barA. The results showed that the $Cu^{32.5}Zn^{7.5}ZrO_2$ catalyst was most active in terms of methanol conversion and hydrogen production. The methanol conversion in steam reforming of methanol was 84.6% at 19.5 barA and furnace $400^{\circ}C$ over $Cu^{32.5}Zn^{7.5}ZrO_2$ catalyst. The catalysts prepared using $ZrO_2$ felt show higher reactor temperature than the pellet type catalyst at same furnace temperature.

• 펄프종이기술
• /
• 제38권1호통권113호
• /
• pp.54-61
• /
• 2006

Basically corrugated board is composed of three layers of different basis weight and stock composition. Warp is well-known for one of the most important problems of corrugated board production. Warp is caused by difference of hygro-expansibility of linears between top and bottom. This research was performed to evaluate the effect of paper properties on the warp of corrugated board. To evaluate warp, dynamic expansion properties of paper was tested using DPM(dynamic penetration measuring system). The effects of sizing, stock composition and wet-pressing on dynamic expansion properties were also evaluated. Commercial base papers showed different dynamic expansion property depending on stock composition and papermaking operation. Sizing treatment decreased and wet-pressing increased the amount of dynamic expansion. To reduce warp of corrugated board, management of dynamic expansion of base papers should be controlled by manipulating moisture, heat and tension, using a variety of adjustments available on the corrugator.

• 한국농공학회논문집
• /
• 제52권4호
• /
• pp.93-101
• /
• 2010

The purpose of this study is to provide basic data for utilization in environment-friendly and economically outstanding CSG construction method by physical and mechanical properties of CSG materials including characteristics of uniaxial compressive strength, microscopic structure and freezing and thawing resistance in accordance with the cement content and curing time of the cement, and size of specimen. In this study, specimens with cement content of 4, 6, 8 and 10% of the total weight were, and, in order to examine the characteristics of the sizes of specimen, specimens with ${\Phi}50{\times}100mm$, ${\Phi}100{\times}200mm$ and ${\Phi}150{\times}300mm$ were manufactured to assess the features including compressive strength, microscopic structure, freezing and thawing, and degree of wet-dry. As results, it was found that with greater size specimen or contents of cement in the specimen, compressive strength, freezing and thawing resistance, and wet-dry resistance increase. Moreover, reactive products for each size of specimen were examined and it was possible to verify that some typical needle structured ettringite was generated due to blending of cement through microscopic structure analysis such as SEM and EDS analysis.

• Journal of the Korean Wood Science and Technology
• /
• 제33권5호통권133호
• /
• pp.66-75
• /
• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1989년도 춘계학술대회
• /
• pp.7-8
• /
• 1989

The graft copolymer of chitosan with amino acid, L-lysine was synthesized by heterogeneous copolymerization and was evaluated as an artificial skin. The mechanical properties under dry and wet state, water content, water vapor transmittance rate and biodegradability were measured. The tensile strength and elongation under wet state ranged $0.3-0.5\;kg/mm^2$, 10-13%, respectively. Water vapor transmittance rate ranged $450-500\;g/m^2{\cdot}day$ like that of the normal skin. The weight loss of prepared membrane by protease IV was measured for the degree of biodegradation. The degree of biodegradation was around 15% and after 4 days it was slow. Biocompatibility was evaluated by studying the attachment of human fibroblast on the prepared membrane surface.

• 펄프종이기술
• /
• 제34권5호
• /
• pp.56-62
• /
• 2002

Alternative way of shaping fibers suitable for papermaking was introduced. Impact refining, which was done simply by hitting wet fibers with a metal weight vertically, was intended to keep the fibers from shortening and to cause mostly internal fibrillation. Virgin chemical pulp, its recycled one and OCC were used in the experiment. It was noticed from the experiment that impact refining on virgin chemical pulp kept the fiber length and increased bonding properties greatly. However, in the recycled fibers from the chemical pulp, fiber length and bonding properties were decreased. In OCC, which seems to contain fractions of semi-chemical pulp and mechanical pulp (GP), and which is recycled pulp from corrugated boxes, fiber length and bonding properties were decreased disastrously. We believe recycled cellulosic fibers (recycled chemical pulp and OCC in this case), which went through hornification, were less resistant to the mechanical impact than virgin chemical pulp. For virgin chemical pulp, impact refining allowed no significant fiber length shortening, high WRV, and high mechanical strength.