• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.242-248
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• 2017

This study was conducted to develop a cylindrical paperpot manufacturing equipment which is capable of continuously producing paperpots with a constant size. The equipment consists of the soil supply part, the paper supply part, the pot manufacturing part, the paperpot cutting part and its process for manufacturing paperpot from the soil supply to the paperpot cutting is continuously performed. As a result of the performance test using this equipment, we suggest that the optimal moisture content and injection pressure to supply soil are 50%~60%, and 0.5 Mpa respectively. Moreover the appropriate temperature for adhesive strength is $150{\sim}160^{\circ}C$ taking into account the performance of device and adhesion time. Also, considering the cutting speed and safety, it is appropriate to adopt a straight blade having a clean plan at a minimum angle of $30^{\circ}$. In addition, the manufacturing capacity of the developed equipment was 3300 pots per hour.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.47-51
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• 2016

It has made a special study of bending behavior of F.R.P. sandwich beams with bonded 2nd-reinforced plies. Specimen's faces were made of chopped mat 300-450, roving clothes 570, core is urethane foam, resin is 713bp unsaturated polyester for ship construction and the mixture weight ratio of resin versus fiber was 55:45 for bending analysis. The purpose of this paper is to study the exact bending behavior of bonded area's deflection and stiffness depends upon various bonded F.R.P. (2nd reinforced ply) length and thickness on which covered joints and to find the optimum design for the sandwich structures. All results and suggestions are based on experiment and using thick face calculation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.11
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• pp.1265-1272
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• 2014

This study performed the progressive failure analysis of adhesive joints of a composite pressure vessel with a separated dome by using a cohesive zone model. In order to determine the input parameters of a cohesive element for numerical analysis, the interlaminar fracture toughness values in modes I and II and in the mixed mode for the adhesive joints of the composite pressure vessel were obtained by a material test. All specimens were manufactured by the filament winding method. A mechanical test was performed on adhesively bonded double-lap joints to determine the shear strength of the adhesive joints and verify the reliability of the cohesive zone model for progressive failure analysis. The test results showed that the shear strength of the adhesive joints was 32MPa; the experiment and analysis results had an error of about 4.4%, indicating their relatively good agreement. The progressive failure analysis of a composite pressure vessel with an adhesively bonded dome performed using the cohesive zone model showed that only 5.8% of the total adhesive length was debonded and this debonded length did not affect the structural integrity of the vessel.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.266-269
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• 1998

세 번수 단사로 제직된 모직물은 그 사용도가 높아지고 있으나 의복의 형태안정성이 문제되고 있다. 형태안정성 중에서 특히 공기중 수분의 흡수, 발산에 따른 수분율의 차이로 발생하는 습윤팽창은 시임 퍼커링, 의복의 뒤틀림, 의복 사이즈의 불량, 접착심지의 이탈등의 다양한 의복 외관상의 문제점을 야기시킬수 있다$^{1-4)}$ . 이러한 모직물의 습윤팽창은 직물의 길이와 두께를 변화시켜서 기공도에 영향을 미치고 나아가 의복의 쾌적감에도 영향을 미치게 된다.(중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.349-354
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• 2002

쌀 소비량은 생활 수준 향상과 외식 및 식품 산업의 발달로 감소하고, 고품질 쌀을 요구하는 성향이 높아지고 있다. 현재, 고품질 쌀을 생산할 수 있는 기술과 제반 요건은 구비되어 있으나, 수확 후 건조·저장 중에 쌀의 품질이 저하된다. 특히 건조 중 품질 저하는 고온건조에 의한 동할 발생 및 과건조가 주요 원인이다. 이를 해결하기 위해 원적외선 건조 시스템에 관한 연구가 진행 중이다. 본 연구에서는 방사율이 높고, 접착성 및 내열성 등이 강한 곡물 건조기용 방사체 코팅원료를 개발하고, 이 원료를 원적외선 방사체에 코팅한 후 방사체의 형태와 크기에 따라 표면 온도 분포 및 연료 소비량 등을 측정 분석하여 방사체의 특성과 적정 조건을 규명하고자 하였다. 연구 결과를 요약하면 다음과 같다. (1) 세라믹 코팅 원료의 배합비는 세라믹분말 40%와 결합재 60%가 접착력과 가열경화 후 표면이 양호한 것으로 나타났다. (2) 노즐의 유량 및 분무각에 따른 버너의 화염길이 및 폭은 노즐유량이 증가함에 따라 증가하는 경향을 나타내었다. (3) 방사체 위치별 표면온도편차는 방사체 길이가 1350mm인 것이 작은 것으로 나타났고, 열풍유동관 직경이 Rounding type의 경우 76.3mm, Right angle type의 경우 89.1mm일 때 표면 온도편차가 적었다. (4) 연료소비량은 열 풍유동관 직경이 클수록, 방사체 길이가 길수록 증가하는 경향을 나타내었고, Right angle type이 Rounding type에 비하여 연료소비량이 약간 높은 것으로 나타났다.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.715-718
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• 1998

In this work, bisphenol type vinyl ester was impregnated into the three-dimensional glass fabrics fabricated from different thickness changes. Their mechanical properties of the specimens have been investigated by three-point bending and flatwise compression tests. Also, interlaminar shear strength (ILSS) has been determined through short-beam test for the evaluation of interfacial adhesion at interfaces between fibers and matrix of the composites. The effect of thickness changes in three-dimensional glass fabric-reinforced composites have been described in this work.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.559-571
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• 2017

This study was conducted to determine the adhesive performances of plywoods affected by layering direction and the amounts of thermoplastic films. The face and back layers of veneer were hardwood species (Mixed light hardwood) and core layer veneer was radiata pine (Pinus radiata D. Don). Thermoplastic film used as adhesive were polypropylene (PP) film and polyethylene (PE) film. Thermal analysis and tensile strength were investigated on each films. As a result, the melting temperature of PP and PE films were $163.4^{\circ}C$ and $109.7^{\circ}C$, respectively, and the crystallization temperature were $98.9^{\circ}C$ and $93.6^{\circ}C$, respectively. Tensile strength and elongation of each films appeared higher on the width direction than length direction. Considering the characteristics of the thermoplastic films, the test for the amount of film used was carried out by layering film to the target thickness on veneer. The effecting of layering direction of film on plywood manufacturing was conducted by laminating in the length and width directions of the film according to the grain direction of veneer. Tensile-shear strength of plywood in wet condition was satisfied with the quality standard (0.7 MPa) of KS F 3101 when the film was used over 0.05 mm of PP film and over 0.10 mm of PE film. Tensile-shear strength of plywood after cyclic boiling exceeded the KS standard when PP film was used 0.20 mm thickness. Furthermore, higher bonding strength was observed on a plywood made with width direction of film according to grain direction of veneer than that of length direction of film. Based on microscopic analysis of the surface and bonding line of plywood, interlocking between veneers by penetration of a thermoplastic film into inner and cracks were observed.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.113-120
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• 2014

This study will evaluate the effectiveness of various pretreatments when fiber-reinforced composite (FRC) post is bonded to endodontically treated tooth with resin cement. Materials and methods: Canal shaping of FRC post (DT Light post, Size 3, Bisco Inc., Schaumburg, IL, USA) was performed on endodontically treated premolars at 1.5 cm from CEJ. Samples were divided into 6 groups of surface treatment after conventional washing and drying to the canal. Total of 24 FRC posts were randomly divided into 6 groups of surface treatment as follows: Group C: control - no surface treatment, Group A: airborne-particle abrasion (Cojet sand, 3M ESPE), Group S: silanization (Bis-silane, Bisco Inc.), Group M: universal primer (Monobond-plus primer, Ivoclar Vivadent Inc.), Group AS: silanization after airborne-particle abrasion, Group AM: universal primer treatment after airborne-particle abrasion. Pretreated fiber posts were cemented with resin-based luting material and photo-polymerized and cut to the thickness of 1 mm. Push-out test using a universal testing machine was performed. Bonding failure strength of post dislodgement was measured and the type of bonding failure was classified. Data were analyzed with Kruskal-Wallis test and multiple comparison groups were performed using Tukey HSD value of rank test (${\alpha}=0.05$). Results: Group AS showed significantly highest bonding strength. Group S, group AM, group A, and group M showed lower bonding strength in order. The control group showed the lowest bonding strength. Conclusion: Surface treatment with silane showed to be the most effective of the surface pretreatment methods for cementation of FRC post. Surface treatment with universal primer showed no significant difference compared with no surface treatment group as for bonding strength.

• Composites Research
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• v.36 no.4
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• pp.246-252
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• 2023

A secondary barrier made of glass fiber reinforced composites has been installed infinitely using automatic bonding machine(ABM) in membrane type LNG cargo containment system (CCS). At the same time, significant thermal stress due to cryogenic heat shrinkage has occurred in the composite on the non-bonding area between the adhesive fixation at both ends. There have been studies from the perspective of structural safety evaluation taking this into account, but none that have analyzed mechanical property taking an prolonged length into account. In this study, 2-parameter Weibull distribution statistical analysis was used to standardize reliable mechanical property for actual length, taking into account the composite's brittle fracture of ceramic material with wide fracture strength dispersion. Related experimental data were obtained by performing uniaxial tensile tests at specific temperatures below cryogenic condition considering LNG environment. As a result, the mechanical strength increased about 1.5 times compared to -20℃ at -70℃ and initial non-linear behavior of fiber stretched was suppressed. As the temperature decreased until the cryogenic, the mechanical strength continued to increase due to cold brittleness. The suggested mechanical property in this study would be employed to secure reliable analysis support material property when assessing the safety of secondary barrier's structures.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.370-376
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• 2001

When an adhesive joint is exposed to high environmental temperature, the tensile load capability of the adhesive joint decreases because the elastic modulus and failure strength of structural adhesive decrease. The thermo-mechanical properties of structural adhesive can be improved by addition of fillers to the adhesive. In this paper, the elastic modulus and failure strength of adhesives as well as the tensile load capability of tubular single lap adhesive joints were experimentally and theoretically investigated with respect to the volume fraction of filler (alumina) and the environmental temperature. Also the tensile modulus of the fille containing epoxy adhesive was predicted using a new equation which considers filler shape, filler content and environmental temperature. The tensile load capability of the adhesive joint was predicted by using the effective strain obtained from the finite element analysis and a new failure model, from which the relation between the bonding length and the crack length was developed with respect to the volume fraction of filler.