• 동력기계공학회지
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• 제13권2호
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• pp.36-41
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• 2009

An experimental investigation was conducted to examine the fluid flow resistance in the rectangular channel with two inclined wire screen baffles. Two different types of wire screens; dutch weave and plain weave, were used as baffle devices in this experiment. Three kinds of baffles with different mesh specifications were made up of dutch type and four different kinds of baffles were made up of plain weave type. The stainless steel wire screen baffles were mounted on the bottom wall with varied angle inclination. Reynolds numbers were varied from 23,000 to 57,000. Results show that the mesh number of baffles plays an important role on friction factor behaviour. It is found that the baffle with the most number of meshes (type SA) has the highest fluid flow resistance.

• 태양에너지
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• 제17권1호
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• pp.47-58
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• 1997

본 연구는 2차원 충돌공기분류계의 포텐셜코어 영역에서 열전달증진을 목적으로 노즐출구와 전열면사이에 메쉬를 설치한후 노즐출구 속도, 메쉬와 전열면사이의 간극, 노즐출구와 전열면사이의 거리를 변화시킬 때의 열전달특성을 메쉬를 설치하지 않은 경우와 비교 검토한 것으로 메쉬를 설치했을 때에는 분류가 전열면에 충돌하면서 소분류로 분할되어 발생하는 난류에 의해 충돌영역에서 열전달성능이 좋아지며, 또한 벽면분류영역으로 진행하면서 홀과 홀사이의 밑부분에서 일어나는 가속으로 인해 열전달성능이 향상된다. 특히 메쉬와 전열면사이의 간극을 변화시켰을 경우 정체점부근에서는 간극이 클수록, 벽면분류영역에서는 간극이 작을수록 전달성능은 향상되며 U=18m/s, H/B=2, C=1인 경우에는 메쉬를 설치하지 않은 평판보다 평균 약 44%의 열전달증진 효과과 있었다. 그리고 본 실험결과를 기존의 난류촉진체를 이용한 연구결과와도 비교 검토하였다.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.817-834
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• 2014

An experimental program was designed in the current work to examine the structural behavior of ferrocement beams reinforced with composite materials under three point loadings up to failure. The experimental program comprised casting and testing of twelve ferrocement beams having the dimensions of 120 mm width, 200 mm depth and 1600 mm length. The twelve beams were different in the type of reinforcements; steel bars, traditional wire meshes (welded and expanded wire meshes) and composite materials (fiberglass wire meshes and polypropylene wire meshes). The flexural performances of the all tested beams in terms of strength, ductility, cracking behavior and energy absorption were investigated. Also all the tested beams were simulated using ANSYS program. The results of the experimental tests concluded that the beam with fiber glass meshes gives the lowest first crack load and ultimate load. The ferrocement beam reinforced with four layers of welded wire meshes has better structural behavior than those beams reinforced with other types of wire meshes. Also the beams reinforced with metal wire meshes give smaller cracks width in comparing with those reinforced with non-metal wire meshes. Also the Finite Element (FE) simulations gave good results comparing with the experimental results.

• Tribology and Lubricants
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• 제23권4호
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• pp.149-155
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• 2007

The CAD model of a elliptical gear for wire cutting has been developed. The rolling contact of pitch ellipses whose rotation axes coincide with their focus has been analyzed, and the perimeter of the pitch ellipse has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. The elliptical gear has been designed by imposing the master tooth on the divided points of the pitch ellipse, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of an elliptical gear is a composite curve of arcs only, and consequently NC codes for wire cutting can be easily generated. Furthermore, a computer simulation program is developed to verify the mesh of the elliptical gear.

• 센서학회지
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• 제22권2호
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• pp.100-104
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• 2013

A superhydrophobic mesh is a unique structure that blocks water, while allowing gases, sound waves, and energy to pass through the holes in the mesh. This mesh is used in various devices, such as gas- and energy-permeable waterproof membranes for underwater sensors and electronic devices. However, it is difficult to fabricate micro- and nano-structures on three-dimensional surfaces, such as the cylindrical surface of a wire mesh. In this research, we successfully produced a superhydrophobic water-repellent mesh with a high contact angle (> $150^{\circ}$) for nanofibrous structures. Conducting polymer (CP) composite nanofibers were evenly coated on a stainless steel mesh surface, to create a superhydrophobic mesh with a pore size of $100{\mu}m$. The nanofiber structure could be controlled by the deposition time. As the deposition time increased, a high-density, hierarchical nanofiber structure was deposited on the mesh. The mesh surface was then coated with Teflon, to reduce the surface energy. The fabricated mesh had a static water contact angle of $163^{\circ}$, and a water-pressure resistance of 1.92 kPa.

• 태양에너지
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• 제12권3호
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• pp.37-46
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• 1992

상변화 물질로 Paraffin wax를 사용한 잠열축열 시스템의 축열성능을 실험을 통하여 조사하였다. 가열유체로는 ethylene glycol을 사용하였고 왁스로의 전열을 위해 열싸이폰을 사용하였다. 왁스의 유효열전도율을 높이기 위해 여러장의 구리망을 왁스에 넣었고 실험은 체적비 2%, 3%, 4%에 대해 유량을 변화시키며 수행하였으며 몇가지 주요결과는 다음과 같다. (1) 구리망은 열전도를 촉진시켜 왁스의 온도를 균일화 하는 역할을 한다. (2) 구리망수의 증가는 열전도를 향상시키는 반면 응해된 왁스의 대류작용을 억제한다. (3) 축열시스템에 최적인 구리망의 수가 존재하며 이 연구에서는 체적비로 나타낼 때 $3{\sim}4%$인 것으로 나타났다.

• 태양에너지
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• 제12권3호
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• pp.28-36
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• 1992

상변화물질로의 열전달기구로써 열싸이폰을 사용하는 잠열 축열 시스템의 축열성능을 실험을 통해 조사하였다. 상변화 물질로는 파라핀 왁스(Sunoco P-116)를 사용하였고 왁스의 유효열전도계수를 높이기 위해 여러겹의 구리망을 왁스에 넣었으며 이 구리망은 열싸이폰의 fin의 역할도 하게했다. 열주입율을 변화시켜 실험을 수행하였으며 주요 결론은 다음과 같다. (1) 구리망 사이의 공간은 용해된 왁스의 대류유동을 허용하여 왁스내의 온도를 비교적 균일하게 해 준다. (2) 구리망의 수가 증가하면 전도열전달은 향상하나 대류작용은 억제된다. (3) 구리망의 수가 증가하면 열싸이폰의 열관류계수와 전 열관류계수는 증가하나 열싸이폰의 응축부와 왁스사이의 열전달계수는 감소한다.

• 한국포장학회지
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• 제29권3호
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• pp.195-201
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• 2023

Garlic (Allium sativum)is a major crop in most Asian countries, and its consumption in Asia-Pacific countries exceeds 90% of the global consumption. It contains beneficial ingredients and numerous essential nutrients, such as manganese, vitamin B6, and vitamin B1. Garlic demand is rising not only in Asian countries but also around the world. Particularly, garlic demand has been steadily increasing in European countries, such as Spain, France, Italy, and the American continent. In South Korea, 331,671 tons and 387,671 tons of garlic was produced in 2018 and 2019, respectively, making the country the fifth ranking garlic producer in the world, and the production has been increasing every year. In this study, the study on temperature distribution in cold storage of Korean garlic in folding wire mesh pallet container using CFD (Computational Fluid Dynamics) analysis was performed and Computations were based a commercial simulation software (ANSYS Workbenh Ver. 18.0). Considering the respiration heat of garlic, the decreasing rate of temperature in the area in contact with the cold air was fast due to the inflow of cold air inside, while the decreasing rate of temperature in the center of the pallet was very low. In order to maintain a uniform temperature distribution inside the agricultural product storage pallet in a low-temperature warehouse, it is considered desirable to install an air passageway to allow low-temperature air to flow into the wire mesh pallet.

• Earthquakes and Structures
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• 제10권2호
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• pp.313-328
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• 2016

Beam-column joints are recognized as one of the most critical and vulnerable zones of a Reinforced Concrete (RC) moment resisting structure subjected to seismic loads. The performance of the deficient beam-column joints can be improved by retrofitting these joints by jacketing them with varied materials like concrete, steel, FRP and ferrocement. In the present study strength behavior of RCC exterior beam-column joints, initially loaded to a prefixed percentage of the ultimate load, and retrofitted using ferrocement jacketing using two different wrapping schemes has been studied and presented. In retrofitting scheme, RS-I, wire mesh is provided in L shape at top and at bottom of the beam-column joint, whereas, in scheme RS-II along with wire mesh in L shape at top and bottom wire mesh is also provided diagonally to the joint. The results of these retrofitted beam-column joints have been compared with those of the controlled joint specimens. The results show an improvement in the ultimate load carrying capacity and yield load of the retrofitted specimens. However, no improvement in the ductility and energy absorption has been observed.

• 대한기계학회논문집
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• 제15권1호
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• pp.274-284
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• 1991

본 연구에서는 몇가지 단순한 스크린의 형상에 대하여 후류의 난류 특성치들 을 계측하여, 실제 현상을 파악하고 자료를 확보하여 앞으로의 연구에 활용하고자 하 였다.본 논문에서는 원형 스크린과 타원형 스크린을 기본 형상으로 택하여, 저항 계수를 변화시키면서, 후류유동장에서 평균속도 분포, 난류 운동에너지, 난류 전단응 력을 열선 풍속계로 계측하였다. 원형 스크린의 경우에는 주로 스크린의 모서리에서 발달하는 전단층의 확산과정을 연구하였고, 타원형 스크린의 경우에는 평균속도 분포 가 하류로 가면서 원형 후류로 발전되어가는 과정을 연구하였다.