• Journal of the Korean Wood Science and Technology
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• 제30권2호
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• pp.108-114
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• 2002

변장 14.0 cm와 16.5 cm인 소나무 정각재의 가열판진공건조와 고주파진공건조간의 건조속도, 함수율분포와 비(比)에너지를 비교하였다. 고주파진공건조는 가열판진공건조보다 건조속도 및 변장이 건조속도에 미치는 영향이 컸었다. 가열판진공건조 목재의 재장방향, 두께방향과 폭방향의 함수율분포는 볼록 형태를 나타내었고, 고주파진공건조 목재는 오목 형태를 나타내었다. 가열판진공건조 목재의 폭방향과 두께방향간의 수분경사는 유사하였으나 고주파진공건조 목재의 경우는 폭방향의 수분경사가 두께방향보다 완만하였다. 가열판진공건조와 고주파 진공건조의 비(比)에너지곡선은 함수율이 감소할수록 증가하는 경향을 나타내었고, 가열판진공건조의 비(比)는 고주파진공건조보다 컸었다.

• 한국가구학회지
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• 제10권2호
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• pp.29-36
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• 1999

During a radio-frequency/vacuum plus press drying process of some hardwood veneers for decoration we investigated the effect of a grain and thickness of a veneer sheet on drying rates, variations of final moisture content within a bundle of veneer sheets, and formation of checking, end waving, and burning mark. About thirty three hundreds sheet of veneer could be dried in sixty five hours from green to in0-use moisture content, and a final moisture content was significantly effected by initial moisture content of veneer. There were nearly variations in a final moisture content among the veneer sheets in the same bundle. A checking was never found in a edge-sliced veneer, and very slight in a flat-sliced veneer of ash and red oak. There were no end waving and no burning mark in all veneer sheets.

• 디자인학연구
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• 제18권4호
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• pp.155-164
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• 2005

가구디자인의 분야는 다른 제품디자인 분야와 다르게 순수 디자인영역과 함께 스튜디오작업을 병행하는 경우가 많다. 이러한 경우는 대량 생산하는 산업가구보다는 다품종 소량생산이나 맞춤형 주문가구, 혹은 부가가치를 극대화한 작품가구 등을 들 수 있으며, 이러한 작업은 주로 소규모의 공방에서 이루어진다. 이와 같은 소규모 가구 스튜디오에서의 디자인과 제작은 대량생산에 비해 형태와 조형성애서 비교적 자유로울 수 있으며 그에 대한 대표적 조형의 요소는 '곡선'이라고 볼 수 있다. 나무는 그 재료적 특성 상 원목의 곡선 카빙을 제외한 자유로운 곡선의 조형이 까다롭기 때문에 특별한 벤딩기법을 적용해야하는데 이를 위해서 본 연구에서는 베큠프레스의 벤딩기법의 효용성과 가능성을 연구하였다. 베큠프레스의 특징과 다양한 기능분석 및 이를 바탕으로 한 기법개발과 실험을 통해서, 특히 가구디자이너를 위한 소규모 스튜디오에서의 베큠프레스의 효율성과 생산성의 가치를 파악하고 보다 효과적인 벤딩의 작업성을 위해 적절한 충족조건 등을 찾아내고자 하였다.

• Composites Research
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• 제33권2호
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• pp.76-80
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• 2020

본 연구에서는 우수한 물성과 표면품질을 가지는 오토클레이브 성형공법의 비효율적인 공정을 개선하여 탈 오토클레이브(Out-of-autoclave, 이하 OOA) 공정으로써 활용이 가능한 진공백 핫 프레스 공정(Vacuum bag hot-press, 이하 V-HP)을 이용하여 탄소섬유 복합재료를 제작하고 오토클레이브(Autoclave, 이하 AC) 공정과 핫 프레스공정(Hot-press, 이하 HP)으로 제작된 복합재료간 물성 및 미세구조를 분석하였으며, OOA공정으로의 가능성을 확인하였다. V-HP공정을 사용한 복합재료의 인장강도는 320.6 MPa로써, AC공정을 이용한 복합재료의 인장강도 335.3 MPa에 상당히 근접한 물성을 보이는 것을 확인하였다. SEM을 이용한 복합재료 표면품질을 확인한 결과 V-HP공정의 경우, 수지내 휘발용매로 인한 기공의 제거상태가 AC공정과 비교하여 다소 낮으나 HP공정과 비교하여 상당히 우수한 표면을 가지는 것을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제6권4호
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• pp.377-389
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• 2014

The vacuum consolidation method which was proposed by Kjellman in 1952 has been studied extensively and used successfully since early 1980 throughout the world, especially in East and Southeast Asia. Despite the increased successful use, different opinions still exist, especially in connection to distribution of vacuum with depth and time in vertical drains and in soil during preloading of soft ground. Porewater pressure measurements from actual cases of field vacuum and vacuum-fill preloading as well as laboratory studies have been examined. It is concluded that (a) a vacuum magnitude equal to that in the drainage blanket remains constant with depth and time within the vertical drains, (b) as expected, vacuum does not develop at the same rate within the soil at different depths; however, under ideal conditions vacuum is expected to become constant with depth in soil after the end of primary consolidation, and (c) there exists a possibility of internal leakage in vacuum intensity at some sublayers of a soft clay and silt deposit. A case history of vacuum loading with sufficient subsurface information is analyzed using the ILLICON procedure.

• Journal of the Korean Wood Science and Technology
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• 제29권1호
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• pp.9-15
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• 2001

침엽수 4수종(소나무, 잣나무, 낙엽송, 웨스턴 햄록)의 가열판 압체식 진공건조에서 소요되는 비에너지 곡선은 함수율 감소에 따라 서서히 증가, 거의 일정, 급속 증가 등 3단계의 증가 패턴을 나타내었고, 제재두께별 계산된 비에너지는 3cm 제재 0.483, 5cm 제재 0.649, 7cm 제재 0.814, 9cm 제재 0.977 및 11cm 제재 1.138kWh/kg로서 두께가 증가함에 따라 거의 직선적으로 증가하였고, 강한 건조스케줄을 적용한 비에너지는 약한 건조스케줄의 것보다 적었으며, 가열판 진공건조의 평균 비에너지는 0.712kWh/kg으로서 다른 건조법의 것보다 적었다.

• 한국재료학회지
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• 제12권12호
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• pp.955-961
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• 2002

2.7vol%TiNi/6061 Al composites with TiNi shape memory alloy as reinforcement were fabricated by vacuum hot press. It was investigated by OM, SEM, EPMA and XRD analysis for the behavior of diffusion layer formation on various heat treatment condition. Thickness of diffusion layer was increased proportionally according to heat treatment time. The layer was formed by the mutual diffusion of TiNi and Al. The diffusion rate from TiNi fiber to Al matrix was faster than that of reverse diffusion path. The more diffused layer was formed in Al matrix. The diffusion at interface layer was consisted of $A1_3$Ti, $Al_3$Ni analyzed by EPMA, XRD results.

• Geomechanics and Engineering
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• 제19권5호
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• pp.447-462
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• 2019

The vacuum preloading method has been used in many countries for ground improvement and land reclamation works. A sand cushion is required as a horizontal drainage channel for conventional vacuum preloading. In terms of the dredged-fill foundation soil, the treatment effect of the conventional vacuum preloading method is poor, particularly in Tianjin, China, where a shortage of sand exists. To solve this problem, straight-line vacuum preloading without sand is widely adopted in engineering practice to improve the foundation soil. Based on the engineering properties of dredged fill in Lingang City, Tianjin, this paper presents field instrumentation in five sections and analyzes the effect of a prefabricated vertical drain (PVD) layout and a vacuum pumping method on the soft soil ground treatment. Through the arrangement of pore water pressure gauges, settlement marks and vane shear tests, the settlement, pore water pressure and subsoil bearing capacity are analyzed to evaluate the effect of the ground treatment. This study demonstrates that straight-line vacuum preloading without sand can be suitable for areas with a high water content. Furthermore, the consolidation settlement and consolidation degree system is developed based on the grey model to predict the consolidation settlement and consolidation degree under vacuum preloading; the validity of the system is also verified.

• Structural Engineering and Mechanics
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• 제72권3호
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• pp.305-312
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• 2019

This paper investigates the effect of utilizing vacuum bagging process to enhance the bond behavior between fiber reinforced polymer (FRP) composites and concrete substrate. Sixty specimens were prepared and tested using double-shear bond test. The effect of various parameters such as vacuum, fiber type, and FRP sheet length and width on the bond strength were investigated. The experimental results revealed that utilizing vacuum leads to improve the bond behavior between FRP composites and concrete. Both the ultimate bond forces and the maximum displacements were enhanced when applying the vacuum which leads to reduction in the amount of FRP materials needed to achieve the required bond strength compared with the un-vacuumed specimens. The efficiency of the enhancement in bond behavior due to vacuum highly depends on the fiber type; using carbon fiber showed higher enhancement in the bond strength compared to the glass fiber when vacuum was applied. On the contrary, specimens with glass fiber showed higher enhancement in the maximum slippage compared to specimens with carbon fibers. Utilizing vacuum does not affect the debonding failure modes but lead to increase in the amount of attached concrete on the surface of the debonded FRP sheet.

• Geomechanics and Engineering
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• 제6권5호
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• pp.419-436
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• 2014

Soil improvement by preloading with PVD in combination with vacuum is helpful when a considerable load is required to meet the desired rate of settlement in a relative short time. To facilitate the vacuum propagation, vertical drains are usually employed in conjunction. This ground improvement method is more and more applied in the Mekong delta of Vietnam to meet the needs of fast infrastructure development. This paper reports on a pilot test that was carried out to investigate the effect of ground improvement by vacuum and PVD on the rate of consolidation at the site of Saigon International Terminals Vietnam (SITV) in Ba Ria-Vung Tau Province, Viet Nam. Three main aspects of the test will be presented, and namely, instrumentation and field monitoring program, calculation of consolidation settlement and back-analysis of soil properties to see the difference before and after ground improvement.