• 한국정밀공학회지
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• 제17권5호
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• pp.63-69
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• 2000

The main target of this research is investigating the relations between mechanical properties and injection conditions, like injection pressure, packing pressure and packing time for various contents ratio of glass fiber and resin. In general idea, high injection pressure produces high strength of molded parts as a monotonic function. but it was revealed that high pressure does not make high strength directly through various experiments of injection molding. In this experiments, PA66 was selected as resin and Glass Fiber was selected as reinforcing fiber Fiber reinforcement was controlled, as 14%, 25%, 33%, 44% of total volume and packing pressure was divided 55%, 65%, 75%, 85% of reference pressure, i.e. 100% equal to 1400kgf/$\textrm{cm}^2$. Finally, tensile testing was executed for injected test specimen. Optimum results based on authors' experiments have been obtained under conditions of 25% and 33% of glass fiber contents. Tensile strength rather depends on the packing pressure and packing time than injection pressure. Especially almost equal value of tensile strength was obtained for various percentage of packing and injection pressure as 65%, 75% and 85% of reference pressure.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1284-1296
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• 2004

In order to investigate effects of anisotropic fiber packing on stresses in composites, a Volume Integral Equation Method is applied to calculate the elastostatic field in an unbounded isotropic elastic medium containing multiple orthotropic inclusions subject to remote loading, and a Mixed Volume and Boundary Integral Equation Method is introduced for the solution of elastostatic problems in unbounded isotropic materials containing multiple anisotropic inclusions as well as one void under uniform remote loading. A detailed analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out for square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively. Also, an analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out, when it is assumed that a void is replaced with one inclusion adjacent to the central inclusion of square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively, due to manufacturing and/or service induced defects. The effects of random orthotropic fiber packing on stresses at the interface between the isotropic matrix and the central orthotropic inclusion are compared with the influences of square and hexagonal orthotropic fiber packing on stresses. Through the analysis of plane elastostatic problems in unbounded isotropic matrix with multiple orthotropic inclusions and one void, it will be established that these new methods are very accurate and effective for investigating effects of general anisotropic fiber packing on stresses in composites.

• 한국세라믹학회지
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• 제50권6호
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• pp.528-532
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• 2013

Well-dispersed slurries of submicron-sized alumina powders were pressure-infiltrated in 3D preforms of mullite fibers and the effects of the particle size and infiltration pressure on the particle packing characteristics were investigated. Infiltration without pressure showed that the packing density increased as the particle size decreased due to the reduction of the friction between the particles and the fibers. The infiltrated preforms contained large pores in the large voids between the fiber tows and small pores in the narrow voids between the individual fibers. Pressure infiltration resulted in a packing density of 77% regardless of the particle size or the infiltration pressure(210 ~ 620 kPa). Pressure infiltration shortened the infiltration time and eliminated the large pores in preforms infiltrated with the slurries of smaller particles. The slurry pressure-infiltration process is thus an efficient method for the packing of matrix materials in various preforms.

• 한국미생물·생명공학회지
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• 제13권3호
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• pp.209-212
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• 1985

산소 투과율이 좋은 silicone tube안쪽에 nutrient 공급을 위한 3개의 isotropic polypropylene hollow fiber 3개를 넣어 제작된 이중 실관 반응기에서 E. coli cell을 immobilization 하여 cell density와 packing characteristics를 조사해 보았다. E. coli cell들은 거의 100% Packing되어 동물조직에서 처럼 층을 이루면서 자랐고 ceil density를 측정해 본 결과 약 550g/$\ell$고농도 세포배양이 가능하였다.

• 대한환경공학회지
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• 제28권2호
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• pp.216-222
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• 2006

본 연구에서는 국내에서 개발되어진 섬유사 필터의 충진밀도와 여과속도가 처리 효율에 미치는 영향에 대한 연구결과를 나타내었다. 0.93 mm의 직경을 가진 폴리아마이드 섬유사가 충진된 직경 40 cm, 높이 2 m의 pilot-scale 규모의 반응기에서 수행되었다. 충진밀도가 섬유사 여과기의 처리효율에 미치는 영향을 살펴보기 위해 여과속도를 325 m/hr로 고정하고 충진밀도를 $70kg/m^3$에서 $100kg/m^3$의 범위에서 운전하였으며, 이와 반대로 여과 속도가 섬유사 여과기의 처리효율에 미치는 영향을 연구하기 위해서 충진밀도를 $70kg/m^3$으로 고정시킨 뒤 여과속도를 65 m/hr에서 400 m/hr의 범위로 운전하였다. 충진밀도가 증가할수록 여과 압력은 기하급수적으로 증가하였다. 탁도 및 SS 제거효율은 $80kg/m^3$까지는 30% 이내의 낮은 제거효율을 나타내었으며, $100kg/m^3$에서도 50% 이하의 낮은 제거효율을 나타내었다. 여과속도에 따른 섬유사 여과기의 여과압력은 여과 속도와 비례적으로 증가하였다. 여과속도가 낮을수록 탁도와 SS의 제거효율도 증가하였으며 65 m/hr에서 73%의 제거 효율을 나타내었다. 전체적으로, 섬유사 여과기를 이용한 입자상 물질의 제거 효율을 개선하기 위해서는 충진 밀도 보다 여과속도를 유입수 특성에 따라 적절히 조절하는 것이 효과적인 것으로 나타났다.

• 한국염색가공학회지
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• 제22권3호
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• pp.257-263
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• 2010

Oil-absorbable nonwovens were produced by meltblown processing of polypropylene chips. In this study, experimental array and variance analysis of the design of experiment were used to increase the field repeatability and universality. Oil absorbency was decreased, as oil absorbable nonwovens of packing density and gearpump speed were increased. Oil absorption rate was increased, as packing density was increased. Also the oil absorption rate increased with increasing gear-pump speed.

• Design & Manufacturing
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• 제2권4호
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• pp.54-61
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• 2008

Warpage, which is one of the molding trouble, acts as possible factor which results in defect in assembly. In this study, a mold was designed to produce specimens with rib parallel to flow direction, specimens with rib perpendicular to flow direction and specimens without rib. This work researched change of warpage according to injection molding condition such as injection pressure, packing pressure, packing time, resin temperature, mold temperature in non-crystalline resins(PC, ABS), crystalline resins(PP, PA66), and 30% glass fiber reinforced-resins(PC, ABS, PP, PA66).Specimens with rib and Crystalline resins show more warpage than specimens without rib and non-crystalline resins, respectively. Glass fiber reinforced-resins and specimens with rib parallel to flow direction show smaller warpage than conventional resins and specimens with rib perpendicular to flow, respectively. Specimens with rib and specimens without rib show reduced warpage as packing time increases. In addition, warpage increase as resin temperature increases. It is found that CAE shows similar tendency with experiment as packing time, resin temperature. when the rib is caused, warpage will reduce and prevent the transformation. product of a irregular form occurs warpage. In the study It'll be basic data that product occurs warpage, preferablity.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.350-351
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• 2003

Polyurethane은 물리적, 화학적 성질이 매우 다른 두 segment(hard/soft)로 이루어진 block copolymer로서 hard segment의 화학적 구조가 hard segment의 packing정도에 영향을 미쳐, PU의 미세상분리 현상을 결정하며 결과적으로 PU의 물리적 성질에 큰 영향을 미치게 된다$^1$. 본 연구에서는 hard segment의 packing을 향상시켜 PU은 열적 기계적 특성을 향상시키기 위하여 방향족환으로 구성되어 있어 aromatic diol의 일종인 hydroxyquinone-di-(beta-hydroxyl)ether(HQEE)를 chain extender로 사용하여 PU를 합성하였다. (중략)

• 한국가구학회지
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• 제14권1호
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• pp.1-9
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• 2003

This research was carried out for packing materials and building materials to examine thylene gas adsorption and effect of keeping fruit fresh of wet formed charcoal-fiber mposite made from defibrated fiber of Pinus densiflora Sieb. et Zucc. and white charcoal from uercus variabilis Bl.(wood fiber: charcoal=8:2, 6:4, 4:6, 2:8), with/without phenol formaldehyde resin(PF, Non volatile content:$52\%$, resin content $1,3,5\%$). The results are summarized as follows: 1. The higher the charcoal content, the more the ethylene gas adsorption. At the same mixing ratio of fiber to charcoal, $\#100-200$ of charcoal particle size gave the better reslts than $\#60-100$. 2. Adding PF into the charcoal fiber composite decreased the capacity of ethylene gas adsorption but there was no significant difference until $5\%$ adding amount of PF. 3. For keeping fruit fresh for a long time, Charcoal fiber composite was $66\%$ longer than control. The higher the white charcoal content, the longer fresh time.

• Fibers and Polymers
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• 제6권1호
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• pp.72-78
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• 2005

The impact of fiber friction, yarn twist, and splicing air pressure on mechanical and structural properties of spliced portion have been reported in the present paper. The mechanical properties include the tensile and bending related properties and, in the structural properties, the diameter and packing density of the splices are studied. A three variable three level facto­rial design approach proposed by Box and Behnken has been used to design the experiment. The results indicate that there is a strong correlation between retained spliced strength (RSS) and retained splice elongation (RSE) with all the experimental variables. It has been observed that RSS increases with the increase in splice air pressure and after certain level it drops, whereas it consistently increases with the increase in yarn twist. The RSE increases with the increase in both fiber friction and yarn twist. It has also been observed that the yarn twist and splicing air pressure have significant influence on splice diameter, percent increase in diameter and retained packing coefficient, but the fiber friction has negligible influence on these parame­ters. Yarn twist and splicing air pressure has a strong correlation with splice flexural rigidity, where as poor correlation with retained flexural rigidity.